Planning, Installation, and Deployment Guide

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Red Hat Certificate System 9

Updated for Red Hat Certificate System 9.7

Florian Delehaye

Red Hat Customer Content Services

fdelehay@redhat.com

Marc Muehlfeld

Red Hat Customer Content Services

Petr Bokoč

Red Hat Customer Content Services

Filip Hanzelka

Red Hat Customer Content Services

Tomáš Čapek

Red Hat Customer Content Services

Aneta Petrová

Red Hat Customer Content Services

Ella Deon Ballard

Red Hat Customer Content Services

Legal Notice

Abstract

This guide covers the major PKI (Public Key Infrastructure) concepts and decision areas for planning a PKI infrastructure.

Part I. Planning How to Deploy Red Hat Certificate System

This section provides an overview of Certificate System, including general PKI principles and specific features of Certificate System and its subsystems. Planning a deployment is vital to designing a PKI infrastructure that adequately meets the needs of your organization.

Chapter 1. Introduction to Public-Key Cryptography

Public-key cryptography and related standards underlie the security features of many products such as signed and encrypted email, single sign-on, and Transport Layer Security/Secure Sockets Layer (SSL/TLS) communications. This chapter covers the basic concepts of public-key cryptography.

Internet traffic, which passes information through intermediate computers, can be intercepted by a third party:

Eavesdropping

Information remains intact, but its privacy is compromised. For example, someone could gather credit card numbers, record a sensitive conversation, or intercept classified information.

Tampering

Information in transit is changed or replaced and then sent to the recipient. For example, someone could alter an order for goods or change a person's resume.

Impersonation

Information passes to a person who poses as the intended recipient. Impersonation can take two forms:

Spoofing. A person can pretend to be someone else. For example, a person can pretend to have the email address jdoe@example.net or a computer can falsely identify itself as a site called www.example.net.
Misrepresentation. A person or organization can misrepresent itself. For example, a site called www.example.net can purport to be an on-line furniture store when it really receives credit-card payments but never sends any goods.

Public-key cryptography provides protection against Internet-based attacks through:

Encryption and decryption: Encryption and decryption allow two communicating parties to disguise information they send to each other. The sender encrypts, or scrambles, information before sending it. The receiver decrypts, or unscrambles, the information after receiving it. While in transit, the encrypted information is unintelligible to an intruder.
Tamper detection: Tamper detection allows the recipient of information to verify that it has not been modified in transit. Any attempts to modify or substitute data are detected.
Authentication: Authentication allows the recipient of information to determine its origin by confirming the sender's identity.
Nonrepudiation: Nonrepudiation prevents the sender of information from claiming at a later date that the information was never sent.

1.1. Encryption and Decryption

Encryption is the process of transforming information so it is unintelligible to anyone but the intended recipient. Decryption is the process of decoding encrypted information. A cryptographic algorithm, also called a cipher, is a mathematical function used for encryption or decryption. Usually, two related functions are used, one for encryption and the other for decryption.

With most modern cryptography, the ability to keep encrypted information secret is based not on the cryptographic algorithm, which is widely known, but on a number called a key that must be used with the algorithm to produce an encrypted result or to decrypt previously encrypted information. Decryption with the correct key is simple. Decryption without the correct key is very difficult, if not impossible.

1.1.1. Symmetric-Key Encryption

With symmetric-key encryption, the encryption key can be calculated from the decryption key and vice versa. With most symmetric algorithms, the same key is used for both encryption and decryption, as shown in Figure 1.1, “Symmetric-Key Encryption”.

Figure 1.1. Symmetric-Key Encryption

Implementations of symmetric-key encryption can be highly efficient, so that users do not experience any significant time delay as a result of the encryption and decryption.

Symmetric-key encryption is effective only if the symmetric key is kept secret by the two parties involved. If anyone else discovers the key, it affects both confidentiality and authentication. A person with an unauthorized symmetric key not only can decrypt messages sent with that key, but can encrypt new messages and send them as if they came from one of the legitimate parties using the key.

Symmetric-key encryption plays an important role in SSL/TLS communication, which is widely used for authentication, tamper detection, and encryption over TCP/IP networks. SSL/TLS also uses techniques of public-key encryption, which is described in the next section.

1.1.2. Public-Key Encryption

Public-key encryption (also called asymmetric encryption) involves a pair of keys, a public key and a private key, associated with an entity. Each public key is published, and the corresponding private key is kept secret. (For more information about the way public keys are published, see Section 1.3, “Certificates and Authentication”.) Data encrypted with a public key can be decrypted only with the corresponding private key. Figure 1.2, “Public-Key Encryption” shows a simplified view of the way public-key encryption works.

Figure 1.2. Public-Key Encryption

The scheme shown in Figure 1.2, “Public-Key Encryption” allows public keys to be freely distributed, while only authorized people are able to read data encrypted using this key. In general, to send encrypted data, the data is encrypted with that person's public key, and the person receiving the encrypted data decrypts it with the corresponding private key.

Compared with symmetric-key encryption, public-key encryption requires more processing and may not be feasible for encrypting and decrypting large amounts of data. However, it is possible to use public-key encryption to send a symmetric key, which can then be used to encrypt additional data. This is the approach used by the SSL/TLS protocols.

The reverse of the scheme shown in Figure 1.2, “Public-Key Encryption” also works: data encrypted with a private key can be decrypted only with the corresponding public key. This is not a recommended practice to encrypt sensitive data, however, because it means that anyone with the public key, which is by definition published, could decrypt the data. Nevertheless, private-key encryption is useful because it means the private key can be used to sign data with a digital signature, an important requirement for electronic commerce and other commercial applications of cryptography. Client software such as Mozilla Firefox can then use the public key to confirm that the message was signed with the appropriate private key and that it has not been tampered with since being signed. Section 1.2, “Digital Signatures” illustrates how this confirmation process works.

1.1.3. Key Length and Encryption Strength

Breaking an encryption algorithm is finding the key to the access the encrypted data in plain text. For symmetric algorithms, breaking the algorithm usually means trying to determine the key used to encrypt the text. For a public key algorithm, breaking the algorithm usually means acquiring the shared secret information between two recipients.

One method of breaking a symmetric algorithm is to simply try every key within the full algorithm until the right key is found. For public key algorithms, since half of the key pair is publicly known, the other half (private key) can be derived using published, though complex, mathematical calculations. Manually finding the key to break an algorithm is called a brute force attack.

Breaking an algorithm introduces the risk of intercepting, or even impersonating and fraudulently verifying, private information.

The key strength of an algorithm is determined by finding the fastest method to break the algorithm and comparing it to a brute force attack.

For symmetric keys, encryption strength is often described in terms of the size or length of the keys used to perform the encryption: longer keys generally provide stronger encryption. Key length is measured in bits.

An encryption key is considered full strength if the best known attack to break the key is no faster than a brute force attempt to test every key possibility.

Different types of algorithms — particularly public key algorithms — may require different key lengths to achieve the same level of encryption strength as a symmetric-key cipher. The RSA cipher can use only a subset of all possible values for a key of a given length, due to the nature of the mathematical problem on which it is based. Other ciphers, such as those used for symmetric-key encryption, can use all possible values for a key of a given length. More possible matching options means more security.

Because it is relatively trivial to break an RSA key, an RSA public-key encryption cipher must have a very long key — at least 2048 bits — to be considered cryptographically strong. On the other hand, symmetric-key ciphers are reckoned to be equivalently strong using a much shorter key length, as little as 80 bits for most algorithms. Similarly, public-key ciphers based on the elliptic curve cryptography (ECC), such as the Elliptic Curve Digital Signature Algorithm (ECDSA) ciphers, also require less bits than RSA ciphers.

1.2. Digital Signatures

Tamper detection relies on a mathematical function called a one-way hash (also called a message digest). A one-way hash is a number of fixed length with the following characteristics:

The value of the hash is unique for the hashed data. Any change in the data, even deleting or altering a single character, results in a different value.
The content of the hashed data cannot be deduced from the hash.

As mentioned in Section 1.1.2, “Public-Key Encryption”, it is possible to use a private key for encryption and the corresponding public key for decryption. Although not recommended when encrypting sensitive information, it is a crucial part of digitally signing any data. Instead of encrypting the data itself, the signing software creates a one-way hash of the data, then uses the private key to encrypt the hash. The encrypted hash, along with other information such as the hashing algorithm, is known as a digital signature.

Figure 1.3, “Using a Digital Signature to Validate Data Integrity” illustrates the way a digital signature can be used to validate the integrity of signed data.

Figure 1.3. Using a Digital Signature to Validate Data Integrity

Figure 1.3, “Using a Digital Signature to Validate Data Integrity” shows two items transferred to the recipient of some signed data: the original data and the digital signature, which is a one-way hash of the original data encrypted with the signer's private key. To validate the integrity of the data, the receiving software first uses the public key to decrypt the hash. It then uses the same hashing algorithm that generated the original hash to generate a new one-way hash of the same data. (Information about the hashing algorithm used is sent with the digital signature.) Finally, the receiving software compares the new hash against the original hash. If the two hashes match, the data has not changed since it was signed. If they do not match, the data may have been tampered with since it was signed, or the signature may have been created with a private key that does not correspond to the public key presented by the signer.

If the two hashes match, the recipient can be certain that the public key used to decrypt the digital signature corresponds to the private key used to create the digital signature. Confirming the identity of the signer also requires some way of confirming that the public key belongs to a particular entity. For more information on authenticating users, see Section 1.3, “Certificates and Authentication”.

A digital signature is similar to a handwritten signature. Once data have been signed, it is difficult to deny doing so later, assuming the private key has not been compromised. This quality of digital signatures provides a high degree of nonrepudiation; digital signatures make it difficult for the signer to deny having signed the data. In some situations, a digital signature is as legally binding as a handwritten signature.

1.3. Certificates and Authentication

1.3.1. A Certificate Identifies Someone or Something

A certificate is an electronic document used to identify an individual, a server, a company, or other entity and to associate that identity with a public key. Like a driver's license or passport, a certificate provides generally recognized proof of a person's identity. Public-key cryptography uses certificates to address the problem of impersonation.

To get personal ID such as a driver's license, a person has to present some other form of identification which confirms that the person is who he claims to be. Certificates work much the same way. Certificate authorities (CAs) validate identities and issue certificates. CAs can be either independent third parties or organizations running their own certificate-issuing server software, such as Certificate System. The methods used to validate an identity vary depending on the policies of a given CA for the type of certificate being requested. Before issuing a certificate, a CA must confirm the user's identity with its standard verification procedures.

The certificate issued by the CA binds a particular public key to the name of the entity the certificate identifies, such as the name of an employee or a server. Certificates help prevent the use of fake public keys for impersonation. Only the public key certified by the certificate will work with the corresponding private key possessed by the entity identified by the certificate.

In addition to a public key, a certificate always includes the name of the entity it identifies, an expiration date, the name of the CA that issued the certificate, and a serial number. Most importantly, a certificate always includes the digital signature of the issuing CA. The CA's digital signature allows the certificate to serve as a valid credential for users who know and trust the CA but do not know the entity identified by the certificate.

For more information about the role of CAs, see Section 1.3.6, “How CA Certificates Establish Trust”.

1.3.2. Authentication Confirms an Identity

Authentication is the process of confirming an identity. For network interactions, authentication involves the identification of one party by another party. There are many ways to use authentication over networks. Certificates are one of those way.

Network interactions typically take place between a client, such as a web browser, and a server. Client authentication refers to the identification of a client (the person assumed to be using the software) by a server. Server authentication refers to the identification of a server (the organization assumed to be running the server at the network address) by a client.

Client and server authentication are not the only forms of authentication that certificates support. For example, the digital signature on an email message, combined with the certificate that identifies the sender, can authenticate the sender of the message. Similarly, a digital signature on an HTML form, combined with a certificate that identifies the signer, can provide evidence that the person identified by that certificate agreed to the contents of the form. In addition to authentication, the digital signature in both cases ensures a degree of nonrepudiation; a digital signature makes it difficult for the signer to claim later not to have sent the email or the form.

Client authentication is an essential element of network security within most intranets or extranets. There are two main forms of client authentication:

Password-based authentication: Almost all server software permits client authentication by requiring a recognized name and password before granting access to the server.
Certificate-based authentication: Client authentication based on certificates is part of the SSL/TLS protocol. The client digitally signs a randomly generated piece of data and sends both the certificate and the signed data across the network. The server validates the signature and confirms the validity of the certificate.

1.3.2.1. Password-Based Authentication

Figure 1.4, “Using a Password to Authenticate a Client to a Server” shows the process of authenticating a user using a user name and password. This example assumes the following:

The user has already trusted the server, either without authentication or on the basis of server authentication over SSL/TLS.
The user has requested a resource controlled by the server.
The server requires client authentication before permitting access to the requested resource.

Figure 1.4. Using a Password to Authenticate a Client to a Server

These are the steps in this authentication process:

When the server requests authentication from the client, the client displays a dialog box requesting the user name and password for that server.
The client sends the name and password across the network, either in plain text or over an encrypted SSL/TLS connection.
The server looks up the name and password in its local password database and, if they match, accepts them as evidence authenticating the user's identity.
The server determines whether the identified user is permitted to access the requested resource and, if so, allows the client to access it.

With this arrangement, the user must supply a new password for each server accessed, and the administrator must keep track of the name and password for each user.

1.3.2.2. Certificate-Based Authentication

One of the advantages of certificate-based authentication is that it can be used to replace the first three steps in authentication with a mechanism that allows the user to supply one password, which is not sent across the network, and allows the administrator to control user authentication centrally. This is called single sign-on.

Figure 1.5, “Using a Certificate to Authenticate a Client to a Server” shows how client authentication works using certificates and SSL/TLS. To authenticate a user to a server, a client digitally signs a randomly generated piece of data and sends both the certificate and the signed data across the network. The server authenticates the user's identity based on the data in the certificate and signed data.

Like Figure 1.4, “Using a Password to Authenticate a Client to a Server”, Figure 1.5, “Using a Certificate to Authenticate a Client to a Server” assumes that the user has already trusted the server and requested a resource and that the server has requested client authentication before granting access to the requested resource.

Figure 1.5. Using a Certificate to Authenticate a Client to a Server

Unlike the authentication process in Figure 1.4, “Using a Password to Authenticate a Client to a Server”, the authentication process in Figure 1.5, “Using a Certificate to Authenticate a Client to a Server” requires SSL/TLS. Figure 1.5, “Using a Certificate to Authenticate a Client to a Server” also assumes that the client has a valid certificate that can be used to identify the client to the server. Certificate-based authentication is preferred to password-based authentication because it is based on the user both possessing the private key and knowing the password. However, these two assumptions are true only if unauthorized personnel have not gained access to the user's machine or password, the password for the client software's private key database has been set, and the software is set up to request the password at reasonably frequent intervals.

Note

Neither password-based authentication nor certificate-based authentication address security issues related to physical access to individual machines or passwords. Public-key cryptography can only verify that a private key used to sign some data corresponds to the public key in a certificate. It is the user's responsibility to protect a machine's physical security and to keep the private-key password secret.

These are the authentication steps shown in Figure 1.5, “Using a Certificate to Authenticate a Client to a Server”:

The client software maintains a database of the private keys that correspond to the public keys published in any certificates issued for that client. The client asks for the password to this database the first time the client needs to access it during a given session, such as the first time the user attempts to access an SSL/TLS-enabled server that requires certificate-based client authentication.
After entering this password once, the user does not need to enter it again for the rest of the session, even when accessing other SSL/TLS-enabled servers.
The client unlocks the private-key database, retrieves the private key for the user's certificate, and uses that private key to sign data randomly-generated from input from both the client and the server. This data and the digital signature are evidence of the private key's validity. The digital signature can be created only with that private key and can be validated with the corresponding public key against the signed data, which is unique to the SSL/TLS session.
The client sends both the user's certificate and the randomly-generated data across the network.
The server uses the certificate and the signed data to authenticate the user's identity.
The server may perform other authentication tasks, such as checking that the certificate presented by the client is stored in the user's entry in an LDAP directory. The server then evaluates whether the identified user is permitted to access the requested resource. This evaluation process can employ a variety of standard authorization mechanisms, potentially using additional information in an LDAP directory or company databases. If the result of the evaluation is positive, the server allows the client to access the requested resource.

Certificates replace the authentication portion of the interaction between the client and the server. Instead of requiring a user to send passwords across the network continually, single sign-on requires the user to enter the private-key database password once, without sending it across the network. For the rest of the session, the client presents the user's certificate to authenticate the user to each new server it encounters. Existing authorization mechanisms based on the authenticated user identity are not affected.

1.3.3. Uses for Certificates

The purpose of certificates is to establish trust. Their usage varies depending on the kind of trust they are used to ensure. Some kinds of certificates are used to verify the identity of the presenter; others are used to verify that an object or item has not been tampered with.

1.3.3.1. SSL/TLS

The Transport Layer Security/Secure Sockets Layer (SSL/TLS) protocol governs server authentication, client authentication, and encrypted communication between servers and clients. SSL/TLS is widely used on the Internet, especially for interactions that involve exchanging confidential information such as credit card numbers.

SSL/TLS requires an SSL/TLS server certificate. As part of the initial SSL/TLS handshake, the server presents its certificate to the client to authenticate the server's identity. The authentication uses public-key encryption and digital signatures to confirm that the server is the server it claims to be. Once the server has been authenticated, the client and server use symmetric-key encryption, which is very fast, to encrypt all the information exchanged for the remainder of the session and to detect any tampering.

Servers may be configured to require client authentication as well as server authentication. In this case, after server authentication is successfully completed, the client must also present its certificate to the server to authenticate the client's identity before the encrypted SSL/TLS session can be established.

For an overview of client authentication over SSL/TLS and how it differs from password-based authentication, see Section 1.3.2, “Authentication Confirms an Identity”.

1.3.3.2. Signed and Encrypted Email

Some email programs support digitally signed and encrypted email using a widely accepted protocol known as Secure Multipurpose Internet Mail Extension (S/MIME). Using S/MIME to sign or encrypt email messages requires the sender of the message to have an S/MIME certificate.

An email message that includes a digital signature provides some assurance that it was sent by the person whose name appears in the message header, thus authenticating the sender. If the digital signature cannot be validated by the email software, the user is alerted.

The digital signature is unique to the message it accompanies. If the message received differs in any way from the message that was sent, even by adding or deleting a single character, the digital signature cannot be validated. Therefore, signed email also provides assurance that the email has not been tampered with. This kind of assurance is known as nonrepudiation, which makes it difficult for the sender to deny having sent the message. This is important for business communication. For information about the way digital signatures work, see Section 1.2, “Digital Signatures”.

S/MIME also makes it possible to encrypt email messages, which is important for some business users. However, using encryption for email requires careful planning. If the recipient of encrypted email messages loses the private key and does not have access to a backup copy of the key, the encrypted messages can never be decrypted.

1.3.3.3. Single Sign-on

Network users are frequently required to remember multiple passwords for the various services they use. For example, a user might have to type a different password to log into the network, collect email, use directory services, use the corporate calendar program, and access various servers. Multiple passwords are an ongoing headache for both users and system administrators. Users have difficulty keeping track of different passwords, tend to choose poor ones, and tend to write them down in obvious places. Administrators must keep track of a separate password database on each server and deal with potential security problems related to the fact that passwords are sent over the network routinely and frequently.

Solving this problem requires some way for a user to log in once, using a single password, and get authenticated access to all network resources that user is authorized to use-without sending any passwords over the network. This capability is known as single sign-on.

Both client SSL/TLS certificates and S/MIME certificates can play a significant role in a comprehensive single sign-on solution. For example, one form of single sign-on supported by Red Hat products relies on SSL/TLS client authentication. A user can log in once, using a single password to the local client's private-key database, and get authenticated access to all SSL/TLS-enabled servers that user is authorized to use-without sending any passwords over the network. This approach simplifies access for users, because they do not need to enter passwords for each new server. It also simplifies network management, since administrators can control access by controlling lists of certificate authorities (CAs) rather than much longer lists of users and passwords.

In addition to using certificates, a complete single-sign on solution must address the need to interoperate with enterprise systems, such as the underlying operating system, that rely on passwords or other forms of authentication.

1.3.3.4. Object Signing

Many software technologies support a set of tools called object signing. Object signing uses standard techniques of public-key cryptography to let users get reliable information about code they download in much the same way they can get reliable information about shrink-wrapped software.

Most important, object signing helps users and network administrators implement decisions about software distributed over intranets or the Internet-for example, whether to allow Java applets signed by a given entity to use specific computer capabilities on specific users' machines.

The objects signed with object signing technology can be applets or other Java code, JavaScript scripts, plug-ins, or any kind of file. The signature is a digital signature. Signed objects and their signatures are typically stored in a special file called a JAR file.

Software developers and others who wish to sign files using object-signing technology must first obtain an object-signing certificate.

1.3.4. Types of Certificates

The Certificate System is capable of generating different types of certificates for different uses and in different formats. Planning which certificates are required and planning how to manage them, including determining what formats are needed and how to plan for renewal, are important to manage both the PKI and the Certificate System instances.

This list is not exhaustive; there are certificate enrollment forms for dual-use certificates for LDAP directories, file-signing certificates, and other subsystem certificates. These forms are available through the Certificate Manager's end-entities page, at https://server.example.com:8443/ca/ee/ca.

When the different Certificate System subsystems are installed, the basic required certificates and keys are generated; for example, configuring the Certificate Manager generates the CA signing certificate for the self-signed root CA and the internal OCSP signing, audit signing, SSL/TLS server, and agent user certificates. During the KRA configuration, the Certificate Manager generates the storage, transport, audit signing, and agent certificates. Additional certificates can be created and installed separately.

Table 1.1. Common Certificates
Certificate Type	Use	Example
Client SSL/TLS certificates	Used for client authentication to servers over SSL/TLS. Typically, the identity of the client is assumed to be the same as the identity of a person, such as an employee. See Section 1.3.2.2, “Certificate-Based Authentication” for a description of the way SSL/TLS client certificates are used for client authentication. Client SSL/TLS certificates can also be used as part of single sign-on.	A bank gives a customer an SSL/TLS client certificate that allows the bank's servers to identify that customer and authorize access to the customer's accounts. A company gives a new employee an SSL/TLS client certificate that allows the company's servers to identify that employee and authorize access to the company's servers.
Server SSL/TLS certificates	Used for server authentication to clients over SSL/TLS. Server authentication may be used without client authentication. Server authentication is required for an encrypted SSL/TLS session. For more information, see Section 1.3.3.1, “SSL/TLS”.	Internet sites that engage in electronic commerce usually support certificate-based server authentication to establish an encrypted SSL/TLS session and to assure customers that they are dealing with the web site identified with the company. The encrypted SSL/TLS session ensures that personal information sent over the network, such as credit card numbers, cannot easily be intercepted.
S/MIME certificates	Used for signed and encrypted email. As with SSL/TLS client certificates, the identity of the client is assumed to be the same as the identity of a person, such as an employee. A single certificate may be used as both an S/MIME certificate and an SSL/TLS certificate; see Section 1.3.3.2, “Signed and Encrypted Email”. S/MIME certificates can also be used as part of single sign-on.	A company deploys combined S/MIME and SSL/TLS certificates solely to authenticate employee identities, thus permitting signed email and SSL/TLS client authentication but not encrypted email. Another company issues S/MIME certificates solely to sign and encrypt email that deals with sensitive financial or legal matters.
CA certificates	Used to identify CAs. Client and server software use CA certificates to determine what other certificates can be trusted. For more information, see Section 1.3.6, “How CA Certificates Establish Trust”.	The CA certificates stored in Mozilla Firefox determine what other certificates can be authenticated. An administrator can implement corporate security policies by controlling the CA certificates stored in each user's copy of Firefox.
Object-signing certificates	Used to identify signers of Java code, JavaScript scripts, or other signed files.	Software companies frequently sign software distributed over the Internet to provide users with some assurance that the software is a legitimate product of that company. Using certificates and digital signatures can also make it possible for users to identify and control the kind of access downloaded software has to their computers.

1.3.4.1. CA Signing Certificates

Every Certificate Manager has a CA signing certificate with a public/private key pair it uses to sign the certificates and certificate revocation lists (CRLs) it issues. This certificate is created and installed when the Certificate Manager is installed.

Note

For more information about CRLs, see Section 2.4.4, “Revoking Certificates and Checking Status”.

The Certificate Manager's status as a root or subordinate CA is determined by whether its CA signing certificate is self-signed or is signed by another CA. Self-signed root CAs set the policies they use to issue certificates, such as the subject names, types of certificates that can be issued, and to whom certificates can be issued. A subordinate CA has a CA signing certificate signed by another CA, usually the one that is a level above in the CA hierarchy (which may or may not be a root CA). If the Certificate Manager is a subordinate CA in a CA hierarchy, the root CA's signing certificate must be imported into individual clients and servers before the Certificate Manager can be used to issue certificates to them.

The CA certificate must be installed in a client if a server or user certificate issued by that CA is installed on that client. The CA certificate confirms that the server certificate can be trusted. Ideally, the certificate chain is installed.

1.3.4.2. Other Signing Certificates

Other services, such as the Online Certificate Status Protocol (OCSP) responder service and CRL publishing, can use signing certificates other than the CA certificate. For example, a separate CRL signing certificate can be used to sign the revocation lists that are published by a CA instead of using the CA signing certificate.

Note

For more information about OCSP, see Section 2.4.4, “Revoking Certificates and Checking Status”.

1.3.4.3. SSL/TLS Server and Client Certificates

Server certificates are used for secure communications, such as SSL/TLS, and other secure functions. Server certificates are used to authenticate themselves during operations and to encrypt data; client certificates authenticate the client to the server.

Note

CAs which have a signing certificate issued by a third-party may not be able to issue server certificates. The third-party CA may have rules in place which prohibit its subordinates from issuing server certificates.

1.3.4.4. User Certificates

End user certificates are a subset of client certificates that are used to identify users to a server or system. Users can be assigned certificates to use for secure communications, such as SSL/TLS, and other functions such as encrypting email or for single sign-on. Special users, such as Certificate System agents, can be given client certificates to access special services.

1.3.4.5. Dual-Key Pairs

Dual-key pairs are a set of two private and public keys, where one set is used for signing and one for encryption. These dual keys are used to create dual certificates. The dual certificate enrollment form is one of the standard forms listed in the end-entities page of the Certificate Manager.

When generating dual-key pairs, set the certificate profiles to work correctly when generating separate certificates for signing and encryption.

1.3.4.6. Cross-Pair Certificates

The Certificate System can issue, import, and publish cross-pair CA certificates. With cross-pair certificates, one CA signs and issues a cross-pair certificate to a second CA, and the second CA signs and issues a cross-pair certificate to the first CA. Both CAs then store or publish both certificates as a crossCertificatePair entry.

Bridging certificates can be done to honor certificates issued by a CA that is not chained to the root CA. By establishing a trust between the Certificate System CA and another CA through a cross-pair CA certificate, the cross-pair certificate can be downloaded and used to trust the certificates issued by the other CA.

1.3.5. Contents of a Certificate

The contents of certificates are organized according to the X.509 v3 certificate specification, which has been recommended by the International Telecommunications Union (ITU), an international standards body.

Users do not usually need to be concerned about the exact contents of a certificate. However, system administrators working with certificates may need some familiarity with the information contained in them.

1.3.5.1. Certificate Data Formats

Certificate requests and certificates can be created, stored, and installed in several different formats. All of these formats conform to X.509 standards.

1.3.5.1.1. Binary

The following binary formats are recognized:

DER-encoded certificate. This is a single binary DER-encoded certificate.
PKCS #7 certificate chain. This is a PKCS #7 SignedData object. The only significant field in the SignedData object is the certificates; the signature and the contents, for example, are ignored. The PKCS #7 format allows multiple certificates to be downloaded at a single time.
Netscape Certificate Sequence. This is a simpler format for downloading certificate chains in a PKCS #7 ContentInfo structure, wrapping a sequence of certificates. The value of the contentType field should be netscape-cert-sequence, while the content field has the following structure:
```
	CertificateSequence ::= SEQUENCE OF Certificate
```
This format allows multiple certificates to be downloaded at the same time.

1.3.5.1.2. Text

Any of the binary formats can be imported in text form. The text form begins with the following line:

-----BEGIN CERTIFICATE-----

Following this line is the certificate data, which can be in any of the binary formats described. This data should be base-64 encoded, as described by RFC 1113. The certificate information is followed by this line:

-----END CERTIFICATE-----

1.3.5.2. Distinguished Names

An X.509 v3 certificate binds a distinguished name (DN) to a public key. A DN is a series of name-value pairs, such as uid=doe, that uniquely identify an entity. This is also called the certificate subject name.

This is an example DN of an employee for Example Corp.:

uid=doe, cn=John Doe,o=Example Corp.,c=US

In this DN, uid is the user name, cn is the user's common name, o is the organization or company name, and c is the country.

DNs may include a variety of other name-value pairs. They are used to identify both certificate subjects and entries in directories that support the Lightweight Directory Access Protocol (LDAP).

The rules governing the construction of DNs can be complex; for comprehensive information about DNs, see A String Representation of Distinguished Names at http://www.ietf.org/rfc/rfc4514.txt.

1.3.5.3. A Typical Certificate

Every X.509 certificate consists of two sections:

The data section

This section includes the following information:

The version number of the X.509 standard supported by the certificate.
The certificate's serial number. Every certificate issued by a CA has a serial number that is unique among the certificates issued by that CA.
Information about the user's public key, including the algorithm used and a representation of the key itself.
The DN of the CA that issued the certificate.
The period during which the certificate is valid; for example, between 1:00 p.m. on November 15, 2004, and 1:00 p.m. November 15, 2020.
The DN of the certificate subject, which is also called the subject name; for example, in an SSL/TLS client certificate, this is the user's DN.
Optional certificate extensions, which may provide additional data used by the client or server. For example:
- the Netscape Certificate Type extension indicates the type of certificate, such as an SSL/TLS client certificate, an SSL/TLS server certificate, or a certificate for signing email
- the Subject Alternative Name (SAN) extension links a certificate to one or more host names
Certificate extensions can also be used for other purposes.

The signature section

This section includes the following information:

The cryptographic algorithm, or cipher, used by the issuing CA to create its own digital signature.
The CA's digital signature, obtained by hashing all of the data in the certificate together and encrypting it with the CA's private key.

Here are the data and signature sections of a certificate shown in the readable pretty-print format:

Certificate:
Data:
   Version: v3 (0x2)
   Serial Number: 3 (0x3)
   Signature Algorithm: PKCS #1 MD5 With RSA Encryption
   Issuer: OU=Example Certificate Authority, O=Example Corp, C=US
   Validity:
    Not Before: Fri Oct 17 18:36:25 1997
    Not  After: Sun Oct 17 18:36:25 1999
   Subject: CN=Jane Doe, OU=Finance, O=Example Corp, C=US
   Subject Public Key Info:
    Algorithm: PKCS #1 RSA Encryption
    Public Key:
       Modulus:
          00:ca:fa:79:98:8f:19:f8:d7:de:e4:49:80:48:e6:2a:2a:86:
          ed:27:40:4d:86:b3:05:c0:01:bb:50:15:c9:de:dc:85:19:22:
          43:7d:45:6d:71:4e:17:3d:f0:36:4b:5b:7f:a8:51:a3:a1:00:
          98:ce:7f:47:50:2c:93:36:7c:01:6e:cb:89:06:41:72:b5:e9:
          73:49:38:76:ef:b6:8f:ac:49:bb:63:0f:9b:ff:16:2a:e3:0e:
          9d:3b:af:ce:9a:3e:48:65:de:96:61:d5:0a:11:2a:a2:80:b0:
          7d:d8:99:cb:0c:99:34:c9:ab:25:06:a8:31:ad:8c:4b:aa:54:
          91:f4:15
       Public Exponent: 65537 (0x10001)
   Extensions:
    Identifier: Certificate Type
      Critical: no
      Certified Usage:
      TLS Client
    Identifier: Authority Key Identifier
      Critical: no
      Key Identifier:
        f2:f2:06:59:90:18:47:51:f5:89:33:5a:31:7a:e6:5c:fb:36:
        26:c9
   Signature:
    Algorithm: PKCS #1 MD5 With RSA Encryption
   Signature:
 6d:23:af:f3:d3:b6:7a:df:90:df:cd:7e:18:6c:01:69:8e:54:65:fc:06:
 30:43:34:d1:63:1f:06:7d:c3:40:a8:2a:82:c1:a4:83:2a:fb:2e:8f:fb:
 f0:6d:ff:75:a3:78:f7:52:47:46:62:97:1d:d9:c6:11:0a:02:a2:e0:cc:
 2a:75:6c:8b:b6:9b:87:00:7d:7c:84:76:79:ba:f8:b4:d2:62:58:c3:c5:
 b6:c1:43:ac:63:44:42:fd:af:c8:0f:2f:38:85:6d:d6:59:e8:41:42:a5:
 4a:e5:26:38:ff:32:78:a1:38:f1:ed:dc:0d:31:d1:b0:6d:67:e9:46:a8:
 d:c4

Here is the same certificate in the base-64 encoded format:

1.3.6. How CA Certificates Establish Trust

CAs validate identities and issue certificates. They can be either independent third parties or organizations running their own certificate-issuing server software, such as the Certificate System.

Any client or server software that supports certificates maintains a collection of trusted CA certificates. These CA certificates determine which issuers of certificates the software can trust, or validate. In the simplest case, the software can validate only certificates issued by one of the CAs for which it has a certificate. It is also possible for a trusted CA certificate to be part of a chain of CA certificates, each issued by the CA above it in a certificate hierarchy.

The sections that follow explains how certificate hierarchies and certificate chains determine what certificates software can trust.

1.3.6.1. CA Hierarchies

In large organizations, responsibility for issuing certificates can be delegated to several different CAs. For example, the number of certificates required may be too large for a single CA to maintain; different organizational units may have different policy requirements; or a CA may need to be physically located in the same geographic area as the people to whom it is issuing certificates.

These certificate-issuing responsibilities can be divided among subordinate CAs. The X.509 standard includes a model for setting up a hierarchy of CAs, shown in Figure 1.6, “Example of a Hierarchy of Certificate Authorities”.

Figure 1.6. Example of a Hierarchy of Certificate Authorities

The root CA is at the top of the hierarchy. The root CA's certificate is a self-signed certificate; that is, the certificate is digitally signed by the same entity that the certificate identifies. The CAs that are directly subordinate to the root CA have CA certificates signed by the root CA. CAs under the subordinate CAs in the hierarchy have their CA certificates signed by the higher-level subordinate CAs.

Organizations have a great deal of flexibility in how CA hierarchies are set up; Figure 1.6, “Example of a Hierarchy of Certificate Authorities” shows just one example.

1.3.6.2. Certificate Chains

CA hierarchies are reflected in certificate chains. A certificate chain is series of certificates issued by successive CAs. Figure 1.7, “Example of a Certificate Chain” shows a certificate chain leading from a certificate that identifies an entity through two subordinate CA certificates to the CA certificate for the root CA, based on the CA hierarchy shown in Figure 1.6, “Example of a Hierarchy of Certificate Authorities”.

Figure 1.7. Example of a Certificate Chain

A certificate chain traces a path of certificates from a branch in the hierarchy to the root of the hierarchy. In a certificate chain, the following occur:

Each certificate is followed by the certificate of its issuer.
Each certificate contains the name (DN) of that certificate's issuer, which is the same as the subject name of the next certificate in the chain.
In Figure 1.7, “Example of a Certificate Chain”, the Engineering CA certificate contains the DN of the CA, USA CA, that issued that certificate. USA CA's DN is also the subject name of the next certificate in the chain.
Each certificate is signed with the private key of its issuer. The signature can be verified with the public key in the issuer's certificate, which is the next certificate in the chain.
In Figure 1.7, “Example of a Certificate Chain”, the public key in the certificate for the USA CA can be used to verify the USA CA's digital signature on the certificate for the Engineering CA.

1.3.6.3. Verifying a Certificate Chain

Certificate chain verification makes sure a given certificate chain is well-formed, valid, properly signed, and trustworthy. The following description of the process covers the most important steps of forming and verifying a certificate chain, starting with the certificate being presented for authentication:

The certificate validity period is checked against the current time provided by the verifier's system clock.
The issuer's certificate is located. The source can be either the verifier's local certificate database on that client or server or the certificate chain provided by the subject, as with an SSL/TLS connection.
The certificate signature is verified using the public key in the issuer's certificate.
The host name of the service is compared against the Subject Alternative Name (SAN) extension. If the certificate has no such extension, the host name is compared against the subject's CN.
The system verifies the Basic Constraint requirements for the certificate, that is, whether the certificate is a CA and how many subsidiaries it is allowed to sign.
If the issuer's certificate is trusted by the verifier in the verifier's certificate database, verification stops successfully here. Otherwise, the issuer's certificate is checked to make sure it contains the appropriate subordinate CA indication in the certificate type extension, and chain verification starts over with this new certificate. Figure 1.8, “Verifying a Certificate Chain to the Root CA” presents an example of this process.

Figure 1.8. Verifying a Certificate Chain to the Root CA

Figure 1.8, “Verifying a Certificate Chain to the Root CA” illustrates what happens when only the root CA is included in the verifier's local database. If a certificate for one of the intermediate CAs, such as Engineering CA, is found in the verifier's local database, verification stops with that certificate, as shown in Figure 1.9, “Verifying a Certificate Chain to an Intermediate CA”.

Figure 1.9. Verifying a Certificate Chain to an Intermediate CA

Expired validity dates, an invalid signature, or the absence of a certificate for the issuing CA at any point in the certificate chain causes authentication to fail. Figure 1.10, “A Certificate Chain That Cannot Be Verified” shows how verification fails if neither the root CA certificate nor any of the intermediate CA certificates are included in the verifier's local database.

Figure 1.10. A Certificate Chain That Cannot Be Verified

1.3.7. Certificate Status

For more information on Certificate Revocation List (CRL), see Section 2.4.4.2.1, “CRLs”

For more information on Online Certificate Status Protocol (OCSP), see Section 2.4.4.2.2, “OCSP Services”

1.4. Certificate Life Cycle

Certificates are used in many applications, from encrypting email to accessing websites. There are two major stages in the lifecycle of the certificate: the point when it is issued (issuance and enrollment) and the period when the certificates are no longer valid (renewal or revocation). There are also ways to manage the certificate during its cycle. Making information about the certificate available to other applications is publishing the certificate and then backing up the key pairs so that the certificate can be recovered if it is lost.

1.4.1. Certificate Issuance

The process for issuing a certificate depends on the CA that issues it and the purpose for which it will be used. Issuing non-digital forms of identification varies in similar ways. The requirements to get a library card are different than the ones to get a driver's license. Similarly, different CAs have different procedures for issuing different kinds of certificates. Requirements for receiving a certificate can be as simple as an email address or user name and password to notarized documents, a background check, and a personal interview.

Depending on an organization's policies, the process of issuing certificates can range from being completely transparent for the user to requiring significant user participation and complex procedures. In general, processes for issuing certificates should be flexible, so organizations can tailor them to their changing needs.

1.4.2. Certificate Expiration and Renewal

Like a driver's license, a certificate specifies a period of time during which it is valid. Attempts to use a certificate for authentication before or after its validity period will fail. Managing certificate expirations and renewals are an essential part of the certificate management strategy. For example, an administrator may wish to be notified automatically when a certificate is about to expire so that an appropriate renewal process can be completed without disrupting the system operation. The renewal process may involve reusing the same public-private key pair or issuing a new one.

Additionally, it may be necessary to revoke a certificate before it has expired, such as when an employee leaves a company or moves to a new job in a different unit within the company.

Certificate revocation can be handled in several different ways:

Verify if the certificate is present in the directory: Servers can be configured so that the authentication process checks the directory for the presence of the certificate being presented. When an administrator revokes a certificate, the certificate can be automatically removed from the directory, and subsequent authentication attempts with that certificate will fail, even though the certificate remains valid in every other respect.
Certificate revocation list (CRL): A list of revoked certificates, a CRL, can be published to the directory at regular intervals. The CRL can be checked as part of the authentication process.
Real-time status checking: The issuing CA can also be checked directly each time a certificate is presented for authentication. This procedure is sometimes called real-time status checking.
Online Certificate Status Protocol: The Online Certificate Status Protocol (OCSP) service can be configured to determine the status of certificates.

For more information about renewing certificates, see Section 2.4.2, “Renewing Certificates”. For more information about revoking certificates, including CRLs and OCSP, see Section 2.4.4, “Revoking Certificates and Checking Status”.

1.5. Key Management

Before a certificate can be issued, the public key it contains and the corresponding private key must be generated. Sometimes it may be useful to issue a single person one certificate and key pair for signing operations and another certificate and key pair for encryption operations. Separate signing and encryption certificates keep the private signing key only on the local machine, providing maximum nonrepudiation. This also aids in backing up the private encryption key in some central location where it can be retrieved in case the user loses the original key or leaves the company.

Keys can be generated by client software or generated centrally by the CA and distributed to users through an LDAP directory. There are costs associated with either method. Local key generation provides maximum nonrepudiation but may involve more participation by the user in the issuing process. Flexible key management capabilities are essential for most organizations.

Key recovery , or the ability to retrieve backups of encryption keys under carefully defined conditions, can be a crucial part of certificate management, depending on how an organization uses certificates. In some PKI setups, several authorized personnel must agree before an encryption key can be recovered to ensure that the key is only recovered to the legitimate owner in authorized circumstance. It can be necessary to recover a key when information is encrypted and can only be decrypted by the lost key.

Chapter 2. Introduction to Red Hat Certificate System

Every common PKI operation, such as issuing, renewing, and revoking certificates; archiving and recovering keys; publishing CRLs and verifying certificate status, is carried out by interoperating subsystems within Red Hat Certificate System. The functions of each individual subsystem and the way that they work together to establish a robust and local PKI is described in this chapter.

2.1. A Review of Certificate System Subsystems

Red Hat Certificate System provides five different subsystems, each focusing on different aspects of a PKI deployment:

A certificate authority called Certificate Manager. The CA is the core of the PKI; it issues and revokes all certificates. The Certificate Manager is also the core of the Certificate System. By establishing a security domain of trusted subsystems, it establishes and manages relationships between the other subsystems.
A key recovery authority (KRA). Certificates are created based on a specific and unique key pair. If a private key is ever lost, then the data which that key was used to access (such as encrypted emails) is also lost because it is inaccessible. The KRA stores key pairs, so that a new, identical certificate can be generated based on recovered keys, and all of the encrypted data can be accessed even after a private key is lost or damaged.
Note
In previous versions of Certificate System, KRA was also referred to as the data recovery manager (DRM). Some code, configuration file entries, web panels, and other resources might still use the term DRM instead of KRA.
An online certificate status protocol (OCSP) responder. The OCSP verifies whether a certificate is valid and not expired. This function can also be done by the CA, which has an internal OCSP service, but using an external OCSP responder lowers the load of the issuing CA.
A token key service (TKS). The TKS derives keys based on the token CCID, private information, and a defined algorithm. These derived keys are used by the TPS to format tokens and enroll certificates on the token.
A token processing system (TPS). The TPS interacts directly with external tokens, like smart cards, and manages the keys and certificates on those tokens through a local client, the Enterprise Security Client (ESC). The ESC contacts the TPS when there is a token operation, and the TPS interacts with the CA, KRA, or TKS, as required, then send the information back to the token by way of the Enterprise Security Client.

Even with all possible subsystems installed, the core of the Certificate System is still the CA (or CAs), since they ultimately process all certificate-related requests. The other subsystems connect to the CA or CAs likes spokes in a wheel. These subsystems work together, in tandem, to create a public key infrastructure (PKI). Depending on what subsystems are installed, a PKI can function in one (or both) of two ways:

A token management system or TMS environment, which manages smart cards. This requires a CA, TKS, and TPS, with an optional KRA for server-side key generation.
A traditional non token management system or non-TMS environment, which manages certificates used in an environment other than smart cards, usually in software databases. At a minimum, a non-TMS requires only a CA, but a non-TMS environment can use OCSP responders and KRA instances as well.

2.2. Overview of Certificate System Subsystems

2.2.1. Separate versus Shared Instances

Red Hat Certificate System supports deployment of separate PKI instances for all subsystems:

Separate PKI instances run as a single Java-based Apache Tomcat instance.
Separate PKI instances contain a single PKI subsystem (CA, KRA, OCSP, TKS, or TPS).
Separate PKI instances must utilize unique ports if co-located on the same physical machine or virtual machine (VM).

Alternatively, Certificate System supports deployment of a shared PKI instance:

Shared PKI instances also run as a single Java-based Apache Tomcat instance.
Shared PKI instances that contain a single PKI subsystem are identical to a separate PKI instance.
Shared PKI instances may contain any combination of up to one of each type of PKI subsystem:
- CA only
- TKS only
- CA and KRA
- CA and OCSP
- TKS and TPS
- CA, KRA, TKS, and TPS
- CA, KRA, OCSP, TKS, and TPS
- etc.
Shared PKI instances allow all of their subsystems contained within that instance to share the same ports.
Shared PKI instances must utilize unique ports if more than one is co-located on the same physical machine or VM.

2.2.2. Instance Installation Prerequisites

2.2.2.1. Directory Server Instance Availability

Prior to installation of a Certificate System instance, a local or remote Red Hat Directory Server LDAP instance must be available. For instructions on installing Red Hat Directory Server, see Red Hat Directory Server Installation Guide.

2.2.2.2. PKI Packages

Red Hat Certificate System is composed of packages listed below:

The following base packages form the core of Certificate System, and are available in base Red Hat Enterprise Linux repositories:
- pki-core.el7
  - pki-base
  - pki-base-java
  - pki-ca
  - pki-javadoc
  - pki-kra
  - pki-server
  - pki-symkey
  - pki-tools
The packages listed below are not available in the base Red Hat Enterprise Linux subscription channel. To install these packages, you must first use Subscription Manager to attach the Red Hat Certificate System subscription pool, and enable the RHCS9 repository. See the Subscription Manager chapter of the Red Hat Enterprise Linux 7 System Administrator's Guide for instructions.
- pki-console.el7pki
  - pki-console
- pki-core.el7pki
  - pki-ocsp
  - pki-tks
  - pki-tps
- redhat-pki.el7pki
  - redhat-pki
- redhat-pki-theme.el7pki
  - redhat-pki-console-theme
  - redhat-pki-server-theme

Use a Red Hat Enterprise Linux 7 system (optionally, use one that has been configured with a supported Hardware Security Module listed in Chapter 4, Supported Platforms), and make sure that all packages are up to date before installing Red Hat Certificate System.

To install all Certificate System packages (with the exception of pki-javadoc), use use Yum to install the redhat-pki metapackage:

# yum install redhat-pki

Alternatively, install one or more of the top level PKI subsystem packages as required; see the list above for exact package names. If you use this approach, make sure to also install the redhat-pki-server-theme package, and optionally redhat-pki-console-theme and pki-console to use the PKI Console.

Finally, developers and administrators may also want to install the JSS and PKI javadocs (the jss-javadoc and pki-javadoc).

Note

The jss-javadoc package requires you to enable the Server-Optional repository in Subscription Manager.

2.2.2.3. Instance Installation and Configuration

The pkispawn command line tool is used to install and configure a new PKI instance. It eliminates the need for separate installation and configuration steps, and may be run either interactively, as a batch process, or a combination of both (batch process with prompts for passwords). The utility does not provide a way to install or configure the browser-based graphical interface.

For usage information, use the pkispawn --help command.

The pkispawn command:

Reads in its default name=value pairs from a plain text configuration file (/etc/pki/default.cfg).
Interactively or automatically overrides any pairs as specified and stores the final result as a Python dictionary.
Executes an ordered series of scriptlets to perform subsystem and instance installation.
The configuration scriptlet packages the Python dictionary as a JavaScript Object Notation (JSON) data object, which is then passed to the Java-based configuration servlet.
The configuration servlet utilizes this data to configure a new PKI subsystem, and then passes control back to the pkispawn executable, which finalizes the PKI setup. A copy of the final deployment file is stored in /var/lib/pki/instance_name/<subsystem>/registry/<subsystem>/deployment.cfg

See the pkispawn man page for additional information.

The default configuration file, /etc/pki/default.cfg, is a plain text file containing the default installation and configuration values which are read at the beginning of the process described above. It consists of name=value pairs divided into [DEFAULT], [Tomcat], [CA], [KRA], [OCSP], [TKS], and [TPS] sections.

If you use the -s option with pkispawn and specify a subsystem name, then only the section for that subsystem will be read.

The sections have a hierarchy: a name=value pair specified in a subsystem section will override the pair in the [Tomcat] section, which in turn override the pair in the [DEFAULT] section. Default pairs can further be overriden by interactive input, or by pairs in a specified PKI instance configuration file.

Note

Whenever non-interactive files are used to override default name=value pairs, they may be stored in any location and specified at any time. These files are referred to as myconfig.txt in the pkispawn man pages, but they are also often referred to as .ini files, or more generally as PKI instance configuration override files.

See the pki_default.cfg man page for more information.

The Configuration Servlet consists of Java bytecode stored in /usr/share/java/pki/pki-certsrv.jar as com/netscape/certsrv/system/ConfigurationRequest.class. The servlet processes data passed in as a JSON object from the configuration scriptlet using pkispawn, and then returns to pkispawn using Java bytecode served in the same file as com/netscape/certsrv/system/ConfigurationResponse.class.

An example of an interactive installation only involves running the pkispawn command on a command line as root:

# pkispawn

Important

Interactive installation currently only exists for very basic deployments. For example, deployments intent upon using advanced features such as cloning, Elliptic Curve Cryptography (ECC), external CA, Hardware Security Module (HSM), subordinate CA, and others, must provide the necessary override parameters in a separate configuration file.

A non-interactive installation requires a PKI instance configuration override file, and the process may look similar to the following example:

```
# mkdir -p /root/pki
```
Use a text editor such as vim to create a configuration file named /root/pki/ca.cfg with the following contents:
```
[DEFAULT]
pki_admin_password=<password>
pki_client_pkcs12_password=<password>
pki_ds_password=<password>
```
```
# pkispawn -s CA -f /root/pki/ca.cfg
```

See the pkispawn man page for various configuration examples.

2.2.2.4. Instance Removal

To remove an existing PKI instance, use the pkidestroy command. It can be run interactively or as a batch process. Use pkidestroy -h to display detailed usage inforamtion on the command line.

The pkidestroy command reads in a PKI subsystem deployment configuration file which was stored when the subsystem was created (/var/lib/pki/instance_name/<subsystem>/registry/<subsystem>/deployment.cfg), uses the read-in file in order to remove the PKI subsystem, and then removes the PKI instance if it contains no additional subsystems. See the pkidestroy man page for more information.

An interactive removal procedure using pkidestroy may look similar to the following:

# pkidestroy
Subsystem (CA/KRA/OCSP/TKS/TPS) [CA]:
Instance [pki-tomcat]:

Begin uninstallation (Yes/No/Quit)? Yes

Log file: /var/log/pki/pki-ca-destroy.20150928183547.log
Loading deployment configuration from /var/lib/pki/pki-tomcat/ca/registry/ca/deployment.cfg.
Uninstalling CA from /var/lib/pki/pki-tomcat.
rm '/etc/systemd/system/multi-user.target.wants/pki-tomcatd.target'

Uninstallation complete.

A non-interactive removal procedure may look similar to the following example:

# pkidestroy -s CA -i pki-tomcat
Log file: /var/log/pki/pki-ca-destroy.20150928183159.log
Loading deployment configuration from /var/lib/pki/pki-tomcat/ca/registry/ca/deployment.cfg.
Uninstalling CA from /var/lib/pki/pki-tomcat.
rm '/etc/systemd/system/multi-user.target.wants/pki-tomcatd.target'

Uninstallation complete.

2.2.3. Execution Management (systemctl)

2.2.3.1. Starting, Stopping, Restarting, and Obtaining Status

Red Hat Certificate System subsystem instances can be stopped and started using the systemctl execution management system tool on Red Hat Enterprise Linux 7:

# systemctl start <unit-file>@instance_name.service

# systemctl status <unit-file>@instance_name.service

# systemctl stop <unit-file>@instance_name.service

# systemctl restart <unit-file>@instance_name.service

<unit-file> has one of the following values:

pki-tomcatd 			With watchdog disabled
pki-tomcatd-nuxwdog 		With watchdog enabled

For more details on the watchdog service, refer to the Section 2.3.10, “Passwords and Watchdog (nuxwdog)” and Section 13.3.2, “Using the Certificate System Watchdog Service”.

2.2.3.2. Starting the Instance Automatically

The systemctl utility in Red Hat Enterprise Linux 7 manages the automatic startup and shutdown settings for each process on the server. This means that when a system reboots, some services can be automatically restarted. System unit files control service startup to ensure that services are started in the correct order. The systemd service and systemctl utility are described in the Red Hat Enterprise Linux System Administrator's Guide

Certificate System instances can be managed by systemctl, so this utility can set whether to restart instances automatically. After a Certificate System instance is created, it is enabled on boot. This can be changed by using systemctl:

# systemctl disable pki-tomcatd@instance_name.service

To re-enable the instance:

# systemctl enable pki-tomcatd@instance_name.service

Note

The systemctl enable and systemctl disable commands do not immediately start or stop Certificate System.

2.2.4. Process Management (pki-server and pkidaemon)

2.2.4.1. The pki-server Command Line Tool

The primary process management tool for Red Hat Certificate System is pki-server. Use the pki-server --help command and see the pki-server man page for usage information.

The pki-server command-line interface (CLI) manages local server instances (for example server configuration or system certificates). Invoke the CLI as follows:

$ pki-server [CLI options] <command> [command parameters]

The CLI uses the configuration files and NSS database of the server instance, therefore the CLI does not require any prior initialization. Since the CLI accesses the files directly, it can only be executed by the root user, and it does not require client certificate. Also, the CLI can run regardless of the status of the server; it does not require a running server.

The CLI supports a number of commands organized in a hierarchical structure. To list the top-level commands, execute the CLI without any additional commands or parameters:

$ pki-server

Some commands have subcommands. To list them, execute the CLI with the command name and no additional options. For example:

$ pki-server ca
$ pki-server ca-audit

To view command usage information, use the --help option:

$ pki-server --help
$ pki-server ca-audit-event-find --help

2.2.4.2. Enabling and Disabling an Installed Subsystem Using pki-server

To enable or disable an installed subsystem, use the pki-server utility.

# pki-server subsystem-disable -i instance_id subsystem_id

# pki-server subsystem-enable -i instance_id subsystem_id

Replace subsystem_id with a valid subsystem identifier: ca, kra, tks, ocsp, or tps.

Note

One instance can have only one of each type of subsystem.

For example, to disable the OCSP subsystem on an instance named pki-tomcat:

# pki-server subsystem-disable -i pki-tomcat ocsp

To list the installed subsystems for an instance:

# pki-server subsystem-find -i instance_id

To show the status of a particular subsystem:

# pki-server subsystem-find -i instance_id subsystem_id

2.2.4.3. The pkidaemon Command Line Tool

Another process management tool for Red Hat Certificate System is the pkidaemon tool:

pkidaemon {start|status} instance-type [instance_name]

pkidaemon status tomcat - Provides status information such as on/off, ports, URLs of each PKI subsystem of all PKI instances on the system.
pkidaemon status tomcat instance_name - Provides status information such as on/off, ports, URLs of each PKI subsystem of a specific instance.
pkidaemon start tomcat instance_name.service - Used internally using systemctl.

See the pkidaemon man page for additional information.

2.2.4.4. Finding the Subsystem Web Services URLs

The CA, KRA, OCSP, TKS, and TPS subsystems have web services pages for agents, as well as regular users and administrators, when appropriate. These web services can be accessed by opening the URL to the subsystem host over the subsystem's secure end user's port. For example, for the CA:

https://server.example.com:8443/ca/services

Note

To get a complete list of all of the interfaces, URLs, and ports for an instance, check the status of the service. For example:

pkidaemon status instance_name

The main web services page for each subsystem has a list of available services pages; these are summarized in Table 2.1, “Default Web Services Pages”. To access any service specifically, access the appropriate port and append the appropriate directory to the URL. For example, to access the CA's end entities (regular users) web services:

https://server.example.com:8443/ca/ee/ca

If DNS is not configured, then an IPv4 or IPv6 address can be used to connect to the services pages. For example:

https://192.0.2.1:8443/ca/services
https://[2001:DB8::1111]:8443/ca/services

Note

Anyone can access the end user pages for a subsystem. However, accessing agent or admin web services pages requires that an agent or administrator certificate be issued and installed in the web browser. Otherwise, authentication to the web services fails.

Table 2.1. Default Web Services Pages
Port	Used for SSL/TLS	Used for Client Authentication^[a]	Web Services	Web Service Location
Certificate Manager
8080	No		End Entities	ca/ee/ca
8443	Yes	No	End Entities	ca/ee/ca
8443	Yes	Yes	Agents	ca/agent/ca
8443	Yes	No	Services	ca/services
8443	Yes	No	Console	pkiconsole https://host:port/ca
Key Recovery Authority
8080	No		End Entities^[b]	kra/ee/kra
8443	Yes	No	End Entities^[b]	kra/ee/kra
8443	Yes	Yes	Agents	kra/agent/kra
8443	Yes	No	Services	kra/services
8443	Yes	No	Console	pkiconsole https://host:port/kra
Online Certificate Status Manager
8080	No		End Entities^[c]	ocsp/ee/ocsp
8443	Yes	No	End Entities^[c]	ocsp/ee/ocsp
8443	Yes	Yes	Agents	ocsp/agent/ocsp
8443	Yes	No	Services	ocsp/services
8443	Yes	No	Console	pkiconsole https://host:port/ocsp
Token Key Service
8080	No		End Entities^[b]	tks/ee/tks
8443	Yes	No	End Entities^[b]	tks/ee/tks
8443	Yes	Yes	Agents	tks/agent/tks
8443	Yes	No	Services	tks/services
8443	Yes	No	Console	pkiconsole https://host:port/tks
Token Processing System
8080	No		Unsecure Services	tps/tps
8443	Yes		Secure Services	tps/tps
8080	No		Enterprise Security Client Phone Home	tps/phoneHome
8443	Yes		Enterprise Security Client Phone Home	tps/phoneHome
8443	Yes	Yes	Admin, Agent, and Operator Services ^[d]	tps/ui
^[a] Services with a client authentication value of `No` can be reconfigured to require client authentication. Services which do not have either a `Yes` or `No` value cannot be configured to use client authentication. ^[b] Although this subsystem type does have end entities ports and interfaces, these end-entity services are not accessible through a web browser, as other end-entity services are. ^[c] Although the OCSP does have end entities ports and interfaces, these end-entity services are not accessible through a web browser, as other end-entity services are. End user OCSP services are accessed by a client sending an OCSP request. ^[d] The agent, admin, and operator services are all accessed through the same web services page. Each role can only access specific sections which are only visible to the members of that role.

2.2.4.5. Starting the Certificate System Console

The CA, KRA, OCSP, and TKS subsystems have a Java interface which can be accessed to perform administrative functions. For the KRA, OCSP, and TKS, this includes very basic tasks like configuring logging and managing users and groups. For the CA, this includes other configuration settings such as creating certificate profiles and configuring publishing.

The Console is opened by connecting to the subsystem instance over its SSL/TLS port using the pkiconsole utility. This utility uses the format:

pkiconsole https://server.example.com:admin_port/subsystem_type

The subsystem_type can be ca, kra, ocsp, or tks. For example, this opens the KRA console:

pkiconsole https://server.example.com:8443/kra

If DNS is not configured, then an IPv4 or IPv6 address can be used to connect to the console. For example:

https://192.0.2.1:8443/ca
https://[2001:DB8::1111]:8443/ca

2.3. Certificate System Architecture Overview

Although each provides a different service, all RHCS subsystems (CA, KRA, OCSP, TKS, TPS) share a common architecture. The following architectural diagram shows the common architecture shared by all of these subsystems.

2.3.1. Java Application Server

Java application server is a Java framework to run server applications. The Certificate System is designed to run within a Java application server. Currently the only Java application server supported is Tomcat 8. Support for other application servers may be added in the future. More information can be found at http://tomcat.apache.org/.

Each Certificate System instance is a Tomcat server instance. The Tomcat configuration is stored in server.xml. The following link provides more information about Tomcat configuration: https://tomcat.apache.org/tomcat-8.0-doc/config/.

Each Certificate System subsystem (such as CA or KRA) is deployed as a web application in Tomcat. The web application configuration is stored in a web.xml file, which is defined in Java Servlet 3.1 specification. See https://www.jcp.org/en/jsr/detail?id=340 for details.

The Certificate System configuration itself is stored in CS.cfg.

See Section 2.3.15, “Instance Layout” for the actual locations of these files.

2.3.2. Java Security Manager

Java services have the option of having a Security Manager which defines unsafe and safe operations for applications to perform. When the subsystems are installed, they have the Security Manager enabled automatically, meaning each Tomcat instance starts with the Security Manager running.

The Security Manager is disabled if the instance is created by running pkispawn and using an override configuration file which specifies the pki_security_manager=false option under its own Tomcat section.

The Security Manager can be disabled from an installed instance using the following procedure:

# systemctl stop pki-tomcatd@instance_name.service

or (if using the nuxwdog watchdog)

# systemctl stop pki-tomcatd-nuxwdog@instance_name.service

Open the /etc/sysconfig/instance_name file, and set SECURITY_MANAGER="false"

# systemctl start pki-tomcatd@instance_name.service

or (if using the nuxwdog watchdog)

# systemctl start pki-tomcatd-nuxwdog@instance_name.service

When an instance is started or restarted, a Java security policy is constructed or reconstructed by pkidaemon from the following files:

/usr/share/pki/server/conf/catalina.policy
/usr/share/tomcat/conf/catalina.policy
/var/lib/pki/$PKI_INSTANCE_NAME/conf/pki.policy
/var/lib/pki/$PKI_INSTANCE_NAME/conf/custom.policy

Then, it is saved into /var/lib/pki/instance_name/conf/catalina.policy.

2.3.3. Interfaces

2.3.3.1. Servlet Interface

Each subsystem contains interfaces allowing interaction with various portions of the subsystem. All subsystems share a common administrative interface and have an agent interface that allows for agents to perform the tasks assigned to them. A CA Subsystem has an end-entity interface that allows end-entities to enroll in the PKI. An OCSP Responder subsystem has an end-entity interface allowing end-entities and applications to check for current certificate revocation status. Finally, a TPS has an operator interface.

While the application server provides the connection entry points, Certificate System completes the interfaces by providing the servlets specific to each interface.

The servlets for each subsystem are defined in the corresponding web.xml file. The same file also defines the URL of each servlet and the security requirements to access the servlets. See Section 2.3.1, “Java Application Server” for more information.

2.3.3.2. Administrative Interface

The agent interface provides Java servlets to process HTML form submissions coming from the agent entry point. Based on the information given in each form submission, the agent servlets allow agents to perform agent tasks, such as editing and approving requests for certificate approval, certificate renewal, and certificate revocation, approving certificate profiles. The agent interfaces for a KRA subsystem, or a TKS subsystem, or an OCSP Responder are specific to the subsystems.

In the non-TMS setup, the agent interface is also used for inter-CIMC boundary communication for the CA-to-KRA trusted connection. This connection is protected by SSL client-authentication and differentiated by separate trusted roles called Trusted Managers. Like the agent role, the Trusted Managers (pseudo-users created for inter-CIMC boundary connection only) are required to be SSL client-authenticated. However, unlike the agent role, they are not offered any agent capability.

In the TMS setup, inter-CIMC boundary communication goes from TPS-to-CA, TPS-to-KRA, and TPS-to-TKS.

2.3.3.3. End-Entity Interface

For the CA subsystem, the end-entity interface provides Java servlets to process HTML form submissions coming from the end-entity entry point. Based on the information received from the form submissions, the end-entity servlets allow end-entities to enroll, renew certificates, revoke their own certificates, and pick up issued certificates. The OCSP Responder subsystem's End-Entity interface provides Java servlets to accept and process OCSP requests. The KRA, TKS, and TPS subsystems do not offer any End-Entity services.

2.3.3.4. Operator Interface

The operator interface is only found in the TPS subsystem.

2.3.4. REST Interface

Representational state transfer (REST) is a way to use HTTP to define and organize web services which will simplify interoperability with other applications. Red Hat Certificate System provides a REST interface to access various services on the server.

The REST services in Red Hat Certificate System are implemented using the RESTEasy framework. RESTEasy is actually running as a servlet in the web application, so the RESTEasy configuration can also be found in the web.xml of the corresponding subsystem. More information about RESTEasy can be found at http://resteasy.jboss.org/.

Each REST service is defined as a separate URL. For example:

CA certificate service: http://<host_name>:<port>/ca/rest/certs/
KRA key service: http://<host_name>:<port>/kra/rest/agent/keys/
TKS user service: http://<host_name>:<port>/tks/rest/admin/users/
TPS group service: http://<host_name>:<port>/tps/rest/admin/groups/

Some services can be accessed using plain HTTP connection, but some others may require HTTPS connection for security.

The REST operation is specified as HTTP method (for example, GET, PUT, POST, DELETE). For example, to get the CA users the client will send a GET /ca/rest/users request.

The REST request and response messages can be sent in XML or JSON format. For example:

{
	"id":"admin",
	"UserID":"admin",
	"FullName":"Administrator",
	"Email":"admin@example.com",
	...
}

The REST interface can be accessed using tools such as CLI, Web UI, or generic REST client. Certificate System also provides Java, Python, and JavaScript libraries to access the services programmatically.

The REST interface supports two types of authentication methods:

user name and password
client certificate

The authentication method required by each service is defined in /usr/share/pki/ca/conf/auth-method.properties.

The REST interface may require certain permissions to access the service. The permissions are defined in the ACL resources in LDAP. The REST interface are mapped to the ACL resources in the /usr/share/pki/<subsystem>/conf/acl.properties.

For more information about the REST interface, see http://www.dogtagpki.org/wiki/REST.

2.3.5. JSS

Java Security Services (JSS) provides a Java interface for cryptographic operations performed by NSS. JSS and higher levels of the Certificate System architecture are built with Java Native Interface (JNI), which provides access to native system libraries from within the Java Virtual Machine (JVM). This design allows us to use FIPS approved cryptographic providers such as NSS which are distributed as part of the system. JSS supports most of the security standards and encryption technologies supported by NSS. JSS also provides a pure Java interface for ASN.1 types and BER-DER encoding.

2.3.6. Tomcatjss

Java-based subsystems in Red Hat Certificate System use a single JAR file called tomcatjss as a bridge between the Tomcat Server HTTP engine and JSS, the Java interface for security operations performed by NSS. Tomcatjss is a Java Secure Socket Extension (JSSE) implementation using Java Security Services (JSS) for Tomcat.

Tomcatjss implements the interfaces needed to use TLS and to create TLS sockets. The socket factory, which tomcatjss implements, makes use of the various properties listed below to create a TLS server listening socket and return it to tomcat. Tomcatjss itself, makes use of our java JSS system to ultimately communicate with the native NSS cryptographic services on the machine.

Tomcatjss is loaded when the Tomcat server and the Certificate System classes are loaded. The load process is described below:

The server is started.
Tomcat gets to the point where it needs to create the listening sockets for the Certificate System installation.
The server.xml file is processed. Configuration in this file tells the system to use a socket factory implemented by Tomcatjss.
For each requested socket, Tomcajss reads and processes the included attributes when it creates the socket. The resulting socket will behave as it has been asked to by those parameters.
Once the server is running, we have the required set of listening sockets waiting for incoming connections to the Tomcat-based Certificate System.

Note that when the sockets are created at startup, Tomcatjss is the first entity in Certificate System that actually deals with the underlying JSS security services. Once the first listening socket is processed, an instance of JSS is created for use going forward.

For further details about the server.xml file, see Section 13.4, “Configuration Files for the Tomcat Engine and Web Services”.

2.3.7. PKCS #11

Public-Key Cryptography Standard (PKCS) #11 specifies an API used to communicate with devices that hold cryptographic information and perform cryptographic operations. Because it supports PKCS #11, Certificate System is compatible with a wide range of hardware and software devices.

At least one PKCS #11 module must be available to any Certificate System subsystem instance. A PKCS #11 module (also called a cryptographic module or cryptographic service provider) manages cryptographic services such as encryption and decryption. PKCS #11 modules are analogous to drivers for cryptographic devices that can be implemented in either hardware or software. Certificate System contains a built-in PKCS #11 module and can support third-party modules.

A PKCS #11 module always has one or more slots which can be implemented as physical hardware slots in a physical reader such as smart cards or as conceptual slots in software. Each slot for a PKCS #11 module can in turn contain a token, which is a hardware or software device that actually provides cryptographic services and optionally stores certificates and keys.

The Certificate System defines two types of tokens, the internal and the external. The internal token is used for storing certificate trust anchors. The external token is used for storing key pairs and certificates that belong to the Certificate System subsystems.

2.3.7.1. NSS Soft Token (internal token)

Note

Certificate System uses an NSS soft token for storing certificate trust anchors.

NSS Soft Token is also called an internal token or a software token. The software token consists of two files, which are usually called the certificate database (cert8.db) and key database (key3.db). The files are created during the Certificate System subsystem configuration. These security databases are located in the /var/lib/pki/instance_name/alias directory.

Two cryptographic modules provided by the NSS soft token are included in the Certificate System:

The default internal PKCS #11 module, which comes with two tokens:
- The internal crypto services token, which performs all cryptographic operations such as encryption, decryption, and hashing.
- The internal key storage token ("Certificate DB token"), which handles all communication with the certificate and key database files that store certificates and keys.
The FIPS 140 module. This module complies with the FIPS 140 government standard for cryptographic module implementations. The FIPS 140 module includes a single, built-in FIPS 140 certificate database token, which handles both cryptographic operations and communication with the certificate and key database files.

Specific instructions on how to import certificates onto the NSS soft token are in Chapter 14, Managing Certificate/Key Crypto Token.

For more information on the Network Security Services (NSS), see Mozilla Developer web pages of the same name.

2.3.7.2. Hardware Security Module (HSM, external token)

Note

Certificate System uses an HSM for storing key pairs and certificates that belong to the Certificate System subsystems.

Any PKCS #11 module can be used with the Certificate System. To use an external hardware token with a subsystem, load its PKCS #11 module before the subsystem is configured, and the new token is available to the subsystem.

Available PKCS #11 modules are tracked in the secmod.db database for the subsystem. The modutil utility is used to modify this file when there are changes to the system, such as installing a hardware accelerator to use for signing operations. For more information on modutil, see Network Security Services (NSS) at Mozilla Developer webpage.

PKCS #11 hardware devices also provide key backup and recovery features for the information stored on hardware tokens. Refer to the PKCS #11 vendor documentation for information on retrieving keys from the tokens.

Specific instructions on how to import certificates and to manage the HSM are in Chapter 14, Managing Certificate/Key Crypto Token.

Supported Hardware Security Modules are located in Section 4.4, “Supported Hardware Security Modules”.

2.3.8. Certificate System Serial Number Management

2.3.8.1. Serial Number Ranges

Certificate request and serial numbers are represented by Java’s big integers

By default, due to their efficiency, certificate request numbers, certificate serial numbers, and replica IDs are assigned sequentially for CA subsystems.

Serial number ranges are specifiable for requests, certificates, and replica IDs:

Current serial number management is based on assigning ranges of sequential serial numbers.
Instances request new ranges when crossing below a defined threshold.
Instances store information about a newly acquired range once it is assigned to the instance.
Instances continue using old ranges until all numbers are exhausted from it, and then it moves to the new range.
Cloned subsystems synchronize their range assignment through replication conflicts.

For new clones:

Part of the current range of the master is transferred to a new clone in the process of cloning.
New clones may request a new range if the transferred range is below the defined threshold.

All ranges are configurable at CA instance installation time by adding a [CA] section to the PKI instance override configuration file, and adding the following name=value pairs under that section as needed. Default values which already exist in /etc/pki/default.cfg are shown in the following example:

[CA]
pki_serial_number_range_start=1
pki_serial_number_range_end=10000000
pki_request_number_range_start=1
pki_request_number_range_end=10000000
pki_replica_number_range_start=1
pki_replica_number_range_end=100

2.3.8.2. Random Serial Number Management

In addition to sequential serial number management, Red Hat Certificate System provides optional random serial number management. Using random serial numbers is selectable at CA instance installation time by adding a [CA] section to the PKI instance override file and adding the following name=value pair under that section:

[CA]
pki_random_serial_numbers_enable=True

If selected, certificate request numbers and certificate serial numbers will be selected randomly within the specified ranges.

2.3.9. Security Domain

A security domain is a registry of PKI services. Services such as CAs register information about themselves in these domains so users of PKI services can find other services by inspecting the registry. The security domain service in RHCS manages both the registration of PKI services for Certificate System subsystems and a set of shared trust policies.

See Section 5.3, “Planning Security Domains” for further details.

2.3.10. Passwords and Watchdog (nuxwdog)

In the default setup, an RHCS subsystem instance needs to act as a client and authenticate to some other services, such as an LDAP internal database (unless TLS client authentication is set up, where a certificate will be used for authentication instead), the NSS token database, or sometimes an HSM with a password. The administrator is prompted to set up this password at the time of installation configuration. This password is then written to the file <instance_dir>/conf/password.conf. At the same time, an identifying string is stored in the main configuration file CS.cfg as part of the parameter cms.passwordlist.

The configuration file, CS.cfg, is protected by Red Hat Enterprise Linux, and only accessible by the PKI administrators. No passwords are stored in CS.cfg.

During installation, the installer will select and log into either the internal software token or a hardware cryptographic token. The login passphrase to these tokens is also written to password.conf.

Configuration at a later time can also place passwords into password.conf. LDAP publishing is one example where the newly configured Directory Manager password for the publishing directory is entered into password.conf.

Nuxwdog (watchdog) is a lightweight auxiliary daemon process that is used to start, stop, monitor the status of, and reconfigure server programs. It is most useful when users need to be prompted for passwords to start a server, because it caches these passwords securely in the kernel keyring, so that restarts can be done automatically in the case of a server crash.

Note

Nuxwdog is the only allowed watchdog service.

Once installation is complete, it is possible to remove the password.conf file altogether. On restart, the nuxwdog watchdog program will prompt the administrator for the required passwords, using the parameter cms.passwordlist (and cms.tokenList if an HSM is used) as a list of passwords for which to prompt. The passwords are then cached by nuxwdog in the kernel keyring to allow automated recovery from a server crash. This automated recovery (automatic subsystem restart) happens in case of uncontrolled shutdown (crash). In case of a controlled shutdown by the administrator, administrators are prompted for passwords again.

When using the watchdog service, starting and stopping an RHCS instance is done differently. For details, see Section 13.3.2, “Using the Certificate System Watchdog Service”.

For further information, see Section 13.3, “Managing System Passwords”.

2.3.11. Internal LDAP Database

Red Hat Certificate System employs Red Hat Directory Server (RHDS) as its internal database for storing information such as certificates, requests, users, roles, ACLs, as well as other miscellaneous internal information. Certificate System communicates with the internal LDAP database either with a password, or securely by means of SSL authentication.

If certificate-based authentication is required between a Certificate System instance and Directory Server, it is important to follow instruction to set up trust between these two entities. Proper pkispawn options will also be needed for installing such Certificate System instance.

For details, see Section 6.5, “Installing Red Hat Directory Server”.

2.3.12. Security-Enhanced Linux (SELinux)

SELinux is a collection of mandatory access control rules which are enforced across a system to restrict unauthorized access and tampering. SELinux is described in more detail in Red Hat Enterprise Linux 7 SELinux User's and Administrator's Guide.

Basically, SELinux identifies objects on a system, which can be files, directories, users, processes, sockets, or any other resource on a Linux host. These objects correspond to the Linux API objects. Each object is then mapped to a security context, which defines the type of object and how it is allowed to function on the Linux server.

Objects can be grouped into domains, and then each domain is assigned the proper rules. Each security context has rules which set restrictions on what operations it can perform, what resources it can access, and what permissions it has.

SELinux policies for the Certificate System are incorporated into the standard system SELinux policies. These SELinux policies apply to every subsystem and service used by Certificate System. By running Certificate System with SELinux in enforcing mode, the security of the information created and maintained by Certificate System is enhanced.

Figure 2.1. CA SELinux Port Policy

The Certificate System SELinux policies define the SELinux configuration for every subsystem instance:

Files and directories for each subsystem instance are labeled with a specific SELinux context.
The ports for each subsystem instance are labeled with a specific SELinux context.
All Certificate System processes are constrained within a subsystem-specific domain.
Each domain has specific rules that define what actions that are authorized for the domain.
Any access not specified in the SELinux policy is denied to the Certificate System instance.

For Certificate System, each subsystem is treated as an SELinux object, and each subsystem has unique rules assigned to it. The defined SELinux policies allow Certificate System objects run with SELinux set in enforcing mode.

Every time pkispawn is run to configure a Certificate System subsystem, files and ports associated with that subsystem are labeled with the required SELinux contexts. These contexts are removed when the particular subsystems are removed using pkidestroy.

The central definition in an SELinux policy is the pki_tomcat_t domain. Certificate System instances are Tomcat servers, and the pki_tomcat_t domain extends the policies for a standard tomcat_t Tomcat domain. All Certificate System instances on a server share the same domain.

When each Certificate System process is started, it initially runs in an unconfined domain (unconfined_t) and then transitions into the pki_tomcat_t domain. This process then has certain access permissions, such as write access to log files labeled pki_tomcat_log_t, read and write access to configuration files labeled pki_tomcat_etc_rw_t, or the ability to open and write to http_port_t ports.

The SELinux mode can be changed from enforcing to permissive, or even off, though this is not recommended.

2.3.13. Self-tests

Red Hat Certificate System provides a Self-Test framework which allows the PKI system integrity to be checked during startup or on demand or both. In the event of a non-critical self test failure, the message will be stored in the log file, while in the event of a critical self test failure, the message will be stored in the log file, while the Certificate System subsystem will properly shut down. The administrator is expected to watch the self-test log during the startup of the subsystem if they wish to see the self-test report during startup. They can also view the log after startup.

When a subsystem is shut down due to a self-test failure, it will also be automatically disabled. This is done to ensure that the subsystem does not partially run and produce misleading responses. Once the issue is resolved, the subsystem can be re-enabled by running the following command on the server:

# pki-server subsystem-enable <subsystem>

For details on how to configure self-tests, see Section 17.3.2, “Configuring Self-Tests”.

2.3.14. Logs

The Certificate System subsystems create log files that record events related to activities, such as administration, communications using any of the protocols the server supports, and various other processes employed by the subsystems. While a subsystem instance is running, it keeps a log of information and error messages on all the components it manages. Additionally, the Apache and Tomcat web servers generate error and access logs.

Each subsystem instance maintains its own log files for installation, audit, and other logged functions.

Log plug-in modules are listeners which are implemented as Java™ classes and are registered in the configuration framework.

All the log files and rotated log files, except for audit logs, are located in whatever directory was specified in pki_subsystem_log_path when the instance was created with pkispawn. Regular audit logs are located in the log directory with other types of logs, while signed audit logs are written to /var/log/pki/instance_name/subsystem_name/signedAudit. The default location for logs can be changed by modifying the configuration.

For details about log configuration during the installation and additional information, see Chapter 17, Configuring Logs.

For details about log administration after the installation, see the Configuring Subsystem Logs section in the Red Hat Certificate System Administration Guide.

2.3.14.1. Audit Log

The audit log contains records for selectable events that have been set up as recordable events. You can configure audit logs also to be signed for integrity-checking purposes.

Note

Audit records should be kept according to the audit retention rules specified in -Section 17.4, “Audit Retention”.

2.3.14.2. System Log

This log, system, records information about requests to the server (all HTTP and HTTPS requests) and the responses from the server. Information recorded in this log includes the IP address (both IPv4 and IPv6) of the client machine that accessed the server; operations performed, such as search, add, and edit; and the result of the access, such as the number of entries returned:

id_number processor - [date:time] [number_of_operations] [result] servlet: message

Example 2.1. TKS System Log

10439.http-13443-Processor25 - [19/May/2020:14:16:51 CDT] [11] [3] UGSubsystem: Get User Error User not found

This log is on by default.

2.3.14.3. Transactions Log

This log, transactions, records any kind of operation performed or submitted to the subsystem.

id_number.processor - [date:time] [number_of_operations] [result] servlet: message

These messages are specific to the certificate service, such as the CA receiving certificate requests, the KRA archiving or retrieving keys, and the TKS registering a new TPS. This log can also be used to detect any unauthorized access or activity.

Example 2.2. Transactions Log

11438.http-8443-Processor25 - [27/May/2020:07:56:18 CDT] [1] [1] archival reqID 4 fromAgent agentID: CA-server.example.com-8443 authenticated by noAuthManager is completed DN requested: UID=recoverykey,E=recoverykey@email.com,CN=recover key serial number: 0x3

This log is on by default.

2.3.14.4. Debug Logs

Debug logs, which are enabled by default, are maintained for all subsystems, with varying degrees and types of information.

Debug logs for each subsystem record much more detailed information than system, transaction, and access logs. Debug logs contain very specific information for every operation performed by the subsystem, including plug-ins and servlets which are run, connection information, and server request and response messages.

Services which are recorded to the debug log include authorization requests, processing certificate requests, certificate status checks, and archiving and recovering keys, and access to web services.

The debug logs record detailed information about the processes for the subsystem. Each log entry has the following format:

[date:time] [processor]: servlet: message

The message can be a return message from the subsystem or contain values submitted to the subsystem.

For example, the TKS records this message for connecting to an LDAP server:

[10/Jun/2020:05:14:51][main]: Established LDAP connection using basic authentication to host localhost port 389 as cn=Directory Manager

The processor is main, and the message is the message from the server about the LDAP connection, and there is no servlet.

The CA, on the other hand, records information about certificate operations as well as subsystem connections:

[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.requestowner$ value=KRA-server.example.com-8443

In this case, the processor is the HTTP protocol over the CA's agent port, while it specifies the servlet for handling profiles and contains a message giving a profile parameter (the subsystem owner of a request) and its value (that the KRA initiated the request).

Example 2.3. CA Certificate Request Log Messages

[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.profileapprovedby$ value=admin
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.cert_request$ value=MIIBozCCAZ8wggEFAgQqTfoHMIHHgAECpQ4wDDEKMAgGA1UEAxMBeKaBnzANBgkqhkiG9w0BAQEFAAOB...
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.profile$ value=true
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.cert_request_type$ value=crmf
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.requestversion$ value=1.0.0
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.req_locale$ value=en
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.requestowner$ value=KRA-server.example.com-8443
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.dbstatus$ value=NOT_UPDATED
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.subject$ value=uid=jsmith, e=jsmith@example.com
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.requeststatus$ value=begin
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.auth_token.user$ value=uid=KRA-server.example.com-8443,ou=People,dc=example,dc=com
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.req_key$ value=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDreuEsBWq9WuZ2MaBwtNYxvkLP^M
				HcN0cusY7gxLzB+XwQ/VsWEoObGldg6WwJPOcBdvLiKKfC605wFdynbEgKs0fChV^M
				k9HYDhmJ8hX6+PaquiHJSVNhsv5tOshZkCfMBbyxwrKd8yZ5G5I+2gE9PUznxJaM^M
				HTmlOqm4HwFxzy0RRQIDAQAB
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.auth_token.authmgrinstname$ value=raCertAuth
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.auth_token.uid$ value=KRA-server.example.com-8443
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.auth_token.userid$ value=KRA-server.example.com-8443
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.requestor_name$ value=
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.profileid$ value=caUserCert
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.auth_token.userdn$ value=uid=KRA-server.example.com-4747,ou=People,dc=example,dc=com
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.requestid$ value=20
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.auth_token.authtime$ value=1212782378071
				[06/Jun/2020:14:59:38][http-8443;-Processor24]: ProfileSubmitServlet: key=$request.req_x509info$ value=MIICIKADAgECAgEAMA0GCSqGSIb3DQEBBQUAMEAxHjAcBgNVBAoTFVJlZGJ1ZGNv^M
				bXB1dGVyIERvbWFpbjEeMBwGA1UEAxMVQ2VydGlmaWNhdGUgQXV0aG9yaXR5MB4X^M
				DTA4MDYwNjE5NTkzOFoXDTA4MTIwMzE5NTkzOFowOzEhMB8GCSqGSIb3DQEJARYS^M
				anNtaXRoQGV4YW1wbGUuY29tMRYwFAYKCZImiZPyLGQBARMGanNtaXRoMIGfMA0G^M
				CSqGSIb3DQEBAQUAA4GNADCBiQKBgQDreuEsBWq9WuZ2MaBwtNYxvkLPHcN0cusY^M
				7gxLzB+XwQ/VsWEoObGldg6WwJPOcBdvLiKKfC605wFdynbEgKs0fChVk9HYDhmJ^M
				8hX6+PaquiHJSVNhsv5tOshZkCfMBbyxwrKd8yZ5G5I+2gE9PUznxJaMHTmlOqm4^M
				HwFxzy0RRQIDAQABo4HFMIHCMB8GA1UdIwQYMBaAFG8gWeOJIMt+aO8VuQTMzPBU^M
				78k8MEoGCCsGAQUFBwEBBD4wPDA6BggrBgEFBQcwAYYuaHR0cDovL3Rlc3Q0LnJl^M
				ZGJ1ZGNvbXB1dGVyLmxvY2FsOjkwODAvY2Evb2NzcDAOBgNVHQ8BAf8EBAMCBeAw^M
				HQYDVR0lBBYwFAYIKwYBBQUHAwIGCCsGAQUFBwMEMCQGA1UdEQQdMBuBGSRyZXF1^M
				ZXN0LnJlcXVlc3Rvcl9lbWFpbCQ=

Likewise, the OCSP shows OCSP request information:

[07/Jul/2020:06:25:40][http-11180-Processor25]: OCSPServlet: OCSP Request:
				[07/Jul/2020:06:25:40][http-11180-Processor25]: OCSPServlet:
				MEUwQwIBADA+MDwwOjAJBgUrDgMCGgUABBSEWjCarLE6/BiSiENSsV9kHjqB3QQU

2.3.14.5. Installation Logs

All subsystems keep an install log.

Every time a subsystem is created either through the initial installation or creating additional instances with pkispawn, an installation file with the complete debug output from the installation, including any errors and, if the installation is successful, the URL and PIN to the configuration interface for the instance. The file is created in the /var/log/pki/ directory for the instance with a name in the form pki-subsystem_name-spawn.timestamp.log.

Each line in the install log follows a step in the installation process.

Example 2.4. CA Install Log

				...
				2015-07-22 20:43:13 pkispawn    : INFO     ... finalizing 'pki.server.deployment.scriptlets.finalization'
				2015-07-22 20:43:13 pkispawn    : INFO     ....... cp -p /etc/sysconfig/pki/tomcat/pki-tomcat/ca/deployment.cfg /var/log/pki/pki-tomcat/ca/archive/spawn_deployment.cfg.20150722204136
				2015-07-22 20:43:13 pkispawn    : DEBUG    ........... chmod 660 /var/log/pki/pki-tomcat/ca/archive/spawn_deployment.cfg.20150722204136
				2015-07-22 20:43:13 pkispawn    : DEBUG    ........... chown 26445:26445 /var/log/pki/pki-tomcat/ca/archive/spawn_deployment.cfg.20150722204136
				2015-07-22 20:43:13 pkispawn    : INFO     ....... generating manifest file called '/etc/sysconfig/pki/tomcat/pki-tomcat/ca/manifest'
				2015-07-22 20:43:13 pkispawn    : INFO     ....... cp -p /etc/sysconfig/pki/tomcat/pki-tomcat/ca/manifest /var/log/pki/pki-tomcat/ca/archive/spawn_manifest.20150722204136
				2015-07-22 20:43:13 pkispawn    : DEBUG    ........... chmod 660 /var/log/pki/pki-tomcat/ca/archive/spawn_manifest.20150722204136
				2015-07-22 20:43:13 pkispawn    : DEBUG    ........... chown 26445:26445 /var/log/pki/pki-tomcat/ca/archive/spawn_manifest.20150722204136
				2015-07-22 20:43:13 pkispawn    : INFO     ....... executing 'systemctl enable pki-tomcatd.target'
				2015-07-22 20:43:13 pkispawn    : INFO     ....... executing 'systemctl daemon-reload'
				2015-07-22 20:43:13 pkispawn    : INFO     ....... executing 'systemctl restart pki-tomcatd@pki-tomcat.service'
				2015-07-22 20:43:14 pkispawn    : INFO     END spawning subsystem 'CA' of instance 'pki-tomcat'
				2015-07-22 20:43:14 pkispawn    : DEBUG

2.3.14.6. Tomcat Error and Access Logs

The CA, KRA, OCSP, TKS, and TPS subsystems use a Tomcat web server instance for their agent and end-entities' interfaces.

Error and access logs are created by the Tomcat web server, which are installed with the Certificate System and provide HTTP services. The error log contains the HTTP error messages the server has encountered. The access log lists access activity through the HTTP interface.

Logs created by Tomcat:

admin.timestamp
catalina.timestamp
catalina.out
host-manager.timestamp
localhost.timestamp
localhost_access_log.timestamp
manager.timestamp

These logs are not available or configurable within the Certificate System; they are only configurable within Apache or Tomcat. See the Apache documentation for information about configuring these logs.

2.3.14.7. Self-Tests Log

The self-tests log records information obtained during the self-tests run when the server starts or when the self-tests are manually run. The tests can be viewed by opening this log. This log is not configurable through the Console. This log can only be configured by changing settings in the CS.cfg file. The information about logs in this section does not pertain to this log. See Section 2.6.5, “Self-Tests” for more information about self-tests.

2.3.14.8. `journalctl` Logs

When starting a Certificate System instance, there is a short period of time before the logging subsystem is set up and enabled. During this time, log contents are written to standard out, which is captured by systemd and exposed via the journalctl utility.

To view these logs, run the following command:

# journalctl -u pki-tomcatd@instance_name.service

If using the nuxwdog service:

# journalctl -u pki-tomcatd-nuxwdog@instance_name.service

Often it is helpful to watch these logs as the instance is starting (for example, in the event of a self-test failure on startup). To do this, run these commands in a separate console prior to starting the instance:

# journalctl -f -u pki-tomcatd@instance_name.service

If using the nuxwdog service:

# journalctl -f -u pki-tomcatd-nuxwdog@instance_name.service

2.3.15. Instance Layout

Each Certificate System instance depends on a number of files. Some of them are located in instance-specific folders, while some others are located in a common folder which is shared with other server instances.

For example, the server configuration files are stored in /etc/pki/instance_name/server.xml, which is instance-specific, but the CA servlets are defined in /usr/share/pki/ca/webapps/ca/WEB-INF/web.xml, which is shared by all server instances on the system.

2.3.15.1. File and Directory Locations for Certificate System

Certificate System servers are Tomcat instances which consist of one or more Certificate System subsystems. Certificate System subsystems are web applications that provide specific type of PKI functions. General, shared subsystem information is contained in non-relocatable, RPM-defined shared libraries, Java archive files, binaries, and templates. These are stored in a fixed location.

The directories are instance specific, tied to the instance name. In these examples, the instance name is pki-tomcat; the true value is whatever is specified at the time the subsystem is created with pkispawn.

The directories contain customized configuration files and templates, profiles, certificate databases, and other files for the subsystem.

Table 2.2. Tomcat Instance Information
Setting	Value
Main Directory	/var/lib/pki/pki-tomcat
Configuration Directory	/etc/pki/pki-tomcat
Configuration File	/etc/pki/pki-tomcat/server.xml /etc/pki/pki-tomcat/password.conf
Security Databases	/var/lib/pki/pki-tomcat/alias
Subsystem Certificates	SSL server certificate Subsystem certificate ^[a]
Log Files	/var/log/pki/pki-tomcat
Web Services Files	/usr/share/pki/server/webapps/ROOT - Main page /usr/share/pki/server/webapps/pki/admin - Admin templates /usr/share/pki/server/webapps/pki/js - JavaScript libraries
^[a] The subsystem certificate is always issued by the security domain so that domain-level operations that require client authentication are based on this subsystem certificate.

Note

The /var/lib/pki/instance_name/conf/ directory is a symbolic link to the /etc/pki/instance_name/ directory.

2.3.15.2. CA Subsystem Information

Table 2.3. CA Subsystem Information
Setting	Value
Main Directory	/var/lib/pki/pki-tomcat/ca
Configuration Directory	/etc/pki/pki-tomcat/ca
Configuration File	/etc/pki/pki-tomcat/ca/CS.cfg
Subsystem Certificates	CA signing certificate OCSP signing certificate (for the CA's internal OCSP service) Audit log signing certificate
Log Files	/var/log/pki/pki-tomcat/ca
Install Logs	/var/log/pki/pki-ca-spawn.YYYYMMDDhhmmss.log
Profile Files	/var/lib/pki/pki-tomcat/ca/profiles/ca
Email Notification Templates	/var/lib/pki/pki-tomcat/ca/emails
Web Services Files	/usr/share/pki/ca/webapps/ca/agent - Agent services /usr/share/pki/ca/webapps/ca/admin - Admin services /usr/share/pki/ca/webapps/ca/ee - End user services

2.3.15.3. KRA Subsystem Information

Table 2.4. KRA Subsystem Information
Setting	Value
Main Directory	/var/lib/pki/pki-tomcat/kra
Configuration Directory	/etc/pki/pki-tomcat/kra
Configuration File	/etc/pki/pki-tomcat/kra/CS.cfg
Subsystem Certificates	Transport certificate Storage certificate Audit log signing certificate
Log Files	/var/log/pki/pki-tomcat/kra
Install Logs	/var/log/pki/pki-kra-spawn.YYYYMMDDhhmmss.log
Web Services Files	/usr/share/pki/kra/webapps/kra/agent - Agent services /usr/share/pki/kra/webapps/kra/admin - Admin services

2.3.15.4. OCSP Subsystem Information

Table 2.5. OCSP Subsystem Information
Setting	Value
Main Directory	/var/lib/pki/pki-tomcat/ocsp
Configuration Directory	/etc/pki/pki-tomcat/ocsp
Configuration File	/etc/pki/pki-tomcat/ocsp/CS.cfg
Subsystem Certificates	OCSP signing certificate Audit log signing certificate
Log Files	/var/log/pki/pki-tomcat/ocsp
Install Logs	/var/log/pki/pki-ocsp-spawn.YYYYMMDDhhmmss.log
Web Services Files	/usr/share/pki/ocsp/webapps/ocsp/agent - Agent services /usr/share/pki/ocsp/webapps/ocsp/admin - Admin services

2.3.15.5. TKS Subsystem Information

Table 2.6. TKS Subsystem Information
Setting	Value
Main Directory	/var/lib/pki/pki-tomcat/tks
Configuration Directory	/etc/pki/pki-tomcat/tks
Configuration File	/etc/pki/pki-tomcat/tks/CS.cfg
Subsystem Certificates	Audit log signing certificate
Log Files	/var/log/pki/pki-tomcat/tks
Install Logs	/var/log/pki/pki-tomcat/pki-tks-spawn.YYYYMMDDhhmmss.log

2.3.15.6. TPS Subsystem Information

Table 2.7. TPS Subsystem Information
Setting	Value
Main Directory	/var/lib/pki/pki-tomcat/tps
Configuration Directory	/etc/pki/pki-tomcat/tps
Configuration File	/etc/pki/pki-tomcat/tps/CS.cfg
Subsystem Certificates	Audit log signing certificate
Log Files	/var/log/pki/pki-tomcat/tps
Install Logs	/var/log/pki/pki-tps-spawn.YYYYMMDDhhhmmss.log
Web Services Files	/usr/share/pki/tps/webapps/tps - TPS services

2.3.15.7. Shared Certificate System Subsystem File Locations

There are some directories used by or common to all Certificate System subsystem instances for general server operations, listed in Table 2.8, “Subsystem File Locations”.

Table 2.8. Subsystem File Locations
Directory Location	Contents
/usr/share/pki	Contains common files and templates used to create Certificate System instances. Along with shared files for all subsystems, there are subsystem-specific files in subfolders: pki/ca (CA) pki/kra (KRA) pki/ocsp (OCSP) pki/tks (TKS) pki/tps (TPS)
/usr/bin	Contains the `pkispawn` and `pkidestroy` instance configuration scripts and tools (Java, native, and security) shared by the Certificate System subsystems.
/usr/share/java/pki	Contains Java archive files shared by local Tomcat web applications and shared by the Certificate System subsystems.

2.4. PKI with Certificate System

The Certificate System is comprised of subsystems which each contribute different functions of a public key infrastructure. A PKI environment can be customized to fit individual needs by implementing different features and functions for the subsystems.

Note

A conventional PKI environment provides the basic framework to manage certificates stored in software databases. This is a non-TMS environment, since it does not manage certificates on smart cards. A TMS environment manages the certificates on smart cards.

At a minimum, a non-TMS requires only a CA, but a non-TMS environment can use OCSP responders and KRA instances as well.

2.4.1. Issuing Certificates

As stated, the Certificate Manager is the heart of the Certificate System. It manages certificates at every stage, from requests through enrollment (issuing), renewal, and revocation.

The Certificate System supports enrolling and issuing certificates and processing certificate requests from a variety of end entities, such as web browsers, servers, and virtual private network (VPN) clients. Issued certificates conform to X.509 version 3 standards.

For more information, see About Enrolling and Renewing Certificates.

2.4.1.1. The Enrollment Process

An end entity enrolls in the PKI environment by submitting an enrollment request through the end-entity interface. There can be many kinds of enrollment that use different enrollment methods or require different authentication methods. Different interfaces can also accept different types of Certificate Signing Requests (CSR).

The Certificate Manager supports different ways to submit CSRs, such as using the graphical interface and command-line tools.

2.4.1.1.1. Enrollment Using the User Interface

For each enrollment through the user interface, there is a separate enrollment page created that is specific to the type of enrollment, type of authentication, and the certificate profiles associated with the type of certificate. The forms associated with enrollment can be customized for both appearance and content. Alternatively, the enrollment process can be customized by creating certificate profiles for each enrollment type. Certificate profiles dynamically-generate forms which are customized by configuring the inputs associated with the certificate profile. Different interfaces can also accept different types of Certificate Signing Requests (CSR).

When an end entity enrolls in a PKI by requesting a certificate, the following events can occur, depending on the configuration of the PKI and the subsystems installed:

The end entity provides the information in one of the enrollment forms and submits a request.
The information gathered from the end entity is customizable in the form depending on the information collected to store in the certificate or to authenticate against the authentication method associated with the form. The form creates a request that is then submitted to the Certificate Manager.
The enrollment form triggers the creation of the public and private keys or for dual-key pairs for the request.
The end entity provides authentication credentials before submitting the request, depending on the authentication type. This can be LDAP authentication, PIN-based authentication, or certificate-based authentication.
The request is submitted either to an agent-approved enrollment process or an automated process.
- The agent-approved process, which involves no end-entity authentication, sends the request to the request queue in the agent services interface, where an agent must processes the request. An agent can then modify parts of the request, change the status of the request, reject the request, or approve the request.
  Automatic notification can be set up so an email is sent to an agent any time a request appears in the queue. Also, an automated job can be set to send a list of the contents of the queue to agents on a pre configured schedule.
- The automated process, which involves end-entity authentication, processes the certificate request as soon as the end entity successfully authenticates.
The form collects information about the end entity from an LDAP directory when the form is submitted. For certificate profile-based enrollment, the defaults for the form can be used to collect the user LDAP ID and password.
The certificate profile associated with the form determine aspects of the certificate that is issued. Depending on the certificate profile, the request is evaluated to determine if the request meets the constraints set, if the required information is provided, and the contents of the new certificate.
The form can also request that the user export the private encryption key. If the KRA subsystem is set up with this CA, the end entity's key is requested, and an archival request is sent to the KRA. This process generally requires no interaction from the end entity.
The certificate request is either rejected because it did not meet the certificate profile or authentication requirements, or a certificate is issued.
The certificate is delivered to the end entity.
- In automated enrollment, the certificate is delivered to the user immediately. Since the enrollment is normally through an HTML page, the certificate is returned as a response on another HTML page.
- In agent-approved enrollment, the certificate can be retrieved by serial number or request Id in the end-entity interface.
- If the notification feature is set up, the link where the certificate can be obtained is sent to the end user.
An automatic notice can be sent to the end entity when the certificate is issued or rejected.
The new certificate is stored in the Certificate Manager's internal database.
If publishing is set up for the Certificate Manager, the certificate is published to a file or an LDAP directory.
The internal OCSP service checks the status of certificates in the internal database when a certificate status request is received.

The end-entity interface has a search form for certificates that have been issued and for the CA certificate chain.

By default, the user interface supports CSR in the PKCS #10 and Certificate Request Message Format (CRMF).

2.4.1.1.2. Enrollment Using the Command Line

This section describes the general workflows when enrolling certificates using the command line.

2.4.1.1.2.1. Enrolling Using the `pki` Utility

For details, see:

The pki-cert(1) man page
The Command-Line Interfaces section in the Red Hat Certificate System Administration Guide.

2.4.1.1.2.2. Enrolling with CMC

To enroll a certificate with CMC, proceed as follows:

Generate a PKCS #10 or CRMF certificate signing request (CSR) using a utility, such as PKCS10Client or CRMFPopClient.
Note
If key archival is enabled in the Key Recovery Agent (KRA), use the CRMFPopClient utility with the KRA's transport certificate in Privacy Enhanced Mail (PEM) format set in the kra.transport file.
Use the CMCRequest utility to convert the CSR into a CMC request. The CMCRequest utility uses a configuration file as input. This file contains, for example, the path to the CSR and the CSR's format.
For further details and examples, see the CMCRequest(1) man page.
Use the HttpClient utility to send the CMC request to the CA. HttpClient uses a configuration file with settings, such as the path to the CMC request file and the servlet.
If the HttpClient command succeeds, the utility receives a PKCS #7 chain with CMC status controls from the CA.
For details about what parameters the utility provides, enter the HttpClient command without any parameters.
Use the CMCResponse utility to check the issuance result of the PKCS #7 file generated by HttpClient. If the request is successful, CMCResponse displays the certificate chain in a readable format.
For further details, see the CMCResponse(1) man page.
Import the new certificate into the application. For details, follow the instructions of the application to which you want to import the certificate.
Note
The certificate retrieved by HttpClient is in PKCS #7 format. If the application supports only Base64-encoded certificates, use the BtoA utility to convert the certificate.
Additionally, certain applications require a header and footer for certificates in Privacy Enhanced Mail (PEM) format. If these are required, add them manually to the PEM file after you converted the certificate.

2.4.1.1.2.2.1. CMC Enrollment without POP

In situations when Proof Of Possession (POP) is missing, the HttpClient utility receives an EncryptedPOP CMC status, which is displayed by the CMCResponse command. In this case, enter the CMCRequest command again with different parameters in the configuration file.

For details, see the The CMC Enrollment Process section in the Red Hat Certificate System Administration Guide.

2.4.1.1.2.2.2. Signed CMC Requests

CMC requests can either be signed by a user or a CA agent:

If an agent signs the request, set the authentication method in the profile to CMCAuth.
If a user signs the request, set the authentication method in the profile to CMCUserSignedAuth.

For details, see the CMC Authentication Plug-ins section in the Red Hat Certificate System Administration Guide.

2.4.1.1.2.2.3. Unsigned CMC Requests

When the CMCUserSignedAuth authentication plug-in is configured in the profile, you must use an unsigned CMC request in combination with the Shared Secret authentication mechanism.

Note

Unsigned CMC requests are also called self-signed CMC requests.

For details, see the CMC Authentication Plug-ins section in the Red Hat Certificate System Administration Guide, and Section 13.8.3, “Enabling the CMC Shared Secret Feature”.

2.4.1.1.2.2.4. The Shared Secret Workflow

Certificate System provides the Shared Secret authentication mechanism for CMC requests according to RFC 5272. In order to protect the passphrase, an issuance protection certificate must be provided when using the CMCSharedToken command. The issuance protection certificate works similar to the KRA transport certificate. For further details, see the CMCSharedToken(1) man page and Section 13.8.3, “Enabling the CMC Shared Secret Feature”.

Shared Secret Created by the End Entity User (Preferred)

The following describes the workflow, if the user generates the shared secret:

The end entity user obtains the issuance protection certificate from the CA administrator.
The end entity user uses the CMCSharedToken utility to generate a shared secret token.
Note
The -p option sets the passphrase that is shared between the CA and the user, not the password of the token.
The end entity user sends the encrypted shared token generated by the CMCSharedToken utility to the administrator.
The administrator adds the shared token into the shrTok attribute in the user's LDAP entry.
The end entity user uses the passphrase to set the witness.sharedSecret parameter in the configuration file passed to the CMCRequest utility.

Shared Secret Created by the CA Administrator

The following describes the workflow, if the CA administrator generates the shared secret for a user:

The administrator uses the CMCSharedToken utility to generate a shared secret token for the user.
Note
The -p option sets the passphrase that is shared between the CA and the user, not the password of the token.
The administrator adds the shared token into the shrTok attribute in the user's LDAP entry.
The administrator shares the passphrase with the user.
The end entity user uses the passphrase to set the witness.sharedSecret parameter in the configuration file passed to the CMCRequest utility.

2.4.1.1.2.2.5. Simple CMC Requests

Certificate System allows simple CMC requests. However, this process does not support the same level of security requirements as full CMC requests and, therefore, must only be used in a secure environment.

When using simple CMC requests, set the following in the HttpClient utility's configuration file:

servlet=/ca/ee/ca/profileSubmitCMCSimple?profileId=caECSimpleCMCUserCert

2.4.1.2. Certificate Profiles

The Certificate System uses certificate profiles to configure the content of the certificate, the constraints for issuing the certificate, the enrollment method used, and the input and output forms for that enrollment. A single certificate profile is associated with issuing a particular type of certificate.

A set of certificate profiles is included for the most common certificate types; the profile settings can be modified. Certificate profiles are configured by an administrator, and then sent to the agent services page for agent approval. Once a certificate profile is approved, it is enabled for use. In case of a UI-enrollment, a dynamically-generated HTML form for the certificate profile is used in the end-entities page for certificate enrollment, which calls on the certificate profile. In case of a command line-based enrollment, the certificate profile is called upon to perform the same processing, such as authentication, authorization, input, output, defaults, and constraints. The server verifies that the defaults and constraints set in the certificate profile are met before acting on the request and uses the certificate profile to determine the content of the issued certificate.

The Certificate Manager can issue certificates with any of the following characteristics, depending on the configuration in the profiles and the submitted certificate request:

Certificates that are X.509 version 3-compliant
Unicode support for the certificate subject name and issuer name
Support for empty certificate subject names
Support for customized subject name components
Support for customized extensions

By default, the certificate enrollment profiles are stored in <instance directory>/ca/profiles/ca with names in the format of <profile id>.cfg. LDAP-based profiles are possible with proper pkispawn configuration parameters.

2.4.1.3. Authentication for Certificate Enrollment

Certificate System provides authentication options for certificate enrollment. These include agent-approved enrollment, in which an agent processes the request, and automated enrollment, in which an authentication method is used to authenticate the end entity and then the CA automatically issues a certificate. CMC enrollment is also supported, which automatically processes a request approved by an agent.

2.4.1.4. Cross-Pair Certificates

It is possible to create a trusted relationship between two separate CAs by issuing and storing cross-signed certificates between these two CAs. By using cross-signed certificate pairs, certificates issued outside the organization's PKI can be trusted within the system.

2.4.2. Renewing Certificates

When certificates reach their expiration date, they can either be allowed to lapse, or they can be renewed.

Renewal regenerates a certificate request using the existing key pairs for that certificate, and then resubmits the request to Certificate Manager. The renewed certificate is identical to the original (since it was created from the same profile using the same key material) with one exception — it has a different, later expiration date.

Renewal can make managing certificates and relationships between users and servers much smoother, because the renewed certificate functions precisely as the old one. For user certificates, renewal allows encrypted data to be accessed without any loss.

2.4.3. Publishing Certificates and CRLs

Certificates can be published to files and an LDAP directory, and CRLs to files, an LDAP directory, and an OCSP responder. The publishing framework provides a robust set of tools to publish to all three places and to set rules to define with more detail which types of certificates or CRLs are published where.

2.4.4. Revoking Certificates and Checking Status

End entities can request that their own certificates be revoked. When an end entity makes the request, the certificate has to be presented to the CA. If the certificate and the keys are available, the request is processed and sent to the Certificate Manager, and the certificate is revoked. The Certificate Manager marks the certificate as revoked in its database and adds it to any applicable CRLs.

An agent can revoke any certificate issued by the Certificate Manager by searching for the certificate in the agent services interface and then marking it revoked. Once a certificate is revoked, it is marked revoked in the database and in the publishing directory, if the Certificate is set up for publishing.

If the internal OCSP service has been configured, the service determines the status of certificates by looking them up in the internal database.

Automated notifications can be set to send email messages to end entities when their certificates are revoked by enabling and configuring the certificate revoked notification message.

2.4.4.1. Revoking Certificates

Users can revoke their certificates using:

The end-entity pages. For details, see the Certificate Revocation Pages section in the Red Hat Certificate System Administration Guide.
The CMCRequest utility on the command line. For details, see the Performing a CMC Revocation section in the Red Hat Certificate System Administration Guide.
The pki utility on the command line. For details, see pki-cert(1) man page.

2.4.4.2. Certificate Status

2.4.4.2.1. CRLs

The Certificate System can create certificate revocation lists (CRLs) from a configurable framework which allows user-defined issuing points so a CRL can be created for each issuing point. Delta CRLs can also be created for any issuing point that is defined. CRLs can be issued for each type of certificate, for a specific subset of a type of certificate, or for certificates generated according to a profile or list of profiles. The extensions used and the frequency and intervals when CRLs are published can all be configured.

The Certificate Manager issues X.509-standard CRLs. A CRL can be automatically updated whenever a certificate is revoked or at specified intervals.

2.4.4.2.2. OCSP Services

The Certificate System CA supports the Online Certificate Status Protocol (OCSP) as defined in PKIX standard RFC 2560. The OCSP protocol enables OCSP-compliant applications to determine the state of a certificate, including the revocation status, without having to directly check a CRL published by a CA to the validation authority. The validation authority, which is also called an OCSP responder, checks for the application.

A CA is set up to issue certificates that include the Authority Information Access extension, which identifies an OCSP responder that can be queried for the status of the certificate.
The CA periodically publishes CRLs to an OCSP responder.
The OCSP responder maintains the CRL it receives from the CA.
An OCSP-compliant client sends requests containing all the information required to identify the certificate to the OCSP responder for verification. The applications determine the location of the OCSP responder from the value of the Authority Information Access extension in the certificate being validated.
The OCSP responder determines if the request contains all the information required to process it. If it does not or if it is not enabled for the requested service, a rejection notice is sent. If it does have enough information, it processes the request and sends back a report stating the status of the certificate.

2.4.4.2.2.1. OCSP Response Signing

Every response that the client receives, including a rejection notification, is digitally signed by the responder; the client is expected to verify the signature to ensure that the response came from the responder to which it submitted the request. The key the responder uses to sign the message depends on how the OCSP responder is deployed in a PKI setup. RFC 2560 recommends that the key used to sign the response belong to one of the following:

The CA that issued the certificate whose status is being checked.
A responder with a public key trusted by the client. Such a responder is called a trusted responder.
A responder that holds a specially marked certificate issued to it directly by the CA that revokes the certificates and publishes the CRL. Possession of this certificate by a responder indicates that the CA has authorized the responder to issue OCSP responses for certificates revoked by the CA. Such a responder is called a CA-designated responder or a CA-authorized responder.

The end-entities page of a Certificate Manager includes a form for manually requesting a certificate for the OCSP responder. The default enrollment form includes all the attributes that identify the certificate as an OCSP responder certificate. The required certificate extensions, such as OCSPNoCheck and Extended Key Usage, can be added to the certificate when the certificate request is submitted.

2.4.4.2.2.2. OCSP Responses

The OCSP response that the client receives indicates the current status of the certificate as determined by the OCSP responder. The response could be any of the following:

Good or Verified . Specifies a positive response to the status inquiry, meaning the certificate has not been revoked. It does not necessarily mean that the certificate was issued or that it is within the certificate's validity interval. Response extensions may be used to convey additional information on assertions made by the responder regarding the status of the certificate.
Revoked . Specifies that the certificate has been revoked, either permanently or temporarily.

Based on the status, the client decides whether to validate the certificate.

Note

The OCSP responder will never return a response of Unknown. The response will always be either Good or Revoked.

2.4.4.2.2.3. OCSP Services

There are two ways to set up OCSP services:

The OCSP built into the Certificate Manager
The Online Certificate Status Manager subsystem

In addition to the built-in OCSP service, the Certificate Manager can publish CRLs to an OCSP-compliant validation authority. CAs can be configured to publish CRLs to the Certificate System Online Certificate Status Manager. The Online Certificate Status Manager stores each Certificate Manager's CRL in its internal database and uses the appropriate CRL to verify the revocation status of a certificate when queried by an OCSP-compliant client.

The Certificate Manager can generate and publish CRLs whenever a certificate is revoked and at specified intervals. Because the purpose of an OCSP responder is to facilitate immediate verification of certificates, the Certificate Manager should publish the CRL to the Online Certificate Status Manager every time a certificate is revoked. Publishing only at intervals means that the OCSP service is checking an outdated CRL.

Note

If the CRL is large, the Certificate Manager can take a considerable amount of time to publish the CRL.

The Online Certificate Status Manager stores each Certificate Manager's CRL in its internal database and uses it as the CRL to verify certificates. The Online Certificate Status Manager can also use the CRL published to an LDAP directory, meaning the Certificate Manager does not have to update the CRLs directly to the Online Certificate Status Manager.

2.4.5. Archiving, Recovering, and Rotating Keys

In the world of PKI, private key archival allows parties the possibility to recover the encrypted data in case the private key is lost. Private keys can be lost due to various reasons such as hardware failure, forgotten passwords, lost smartcards, incapacitated password holder, et caetera. Such archival and recovery feature is offered by the Key Recovery Authority (KRA) subsystem of RHCS.

Only keys that are used exclusively for encrypting data should be archived; signing keys in particular should never be archived. Having two copies of a signing key makes it impossible to identify with certainty who used the key; a second archived copy could be used to impersonate the digital identity of the original key owner.

2.4.5.1. Archiving Keys

There are two types of key archival mechanisms provided by KRA:

Client-side key generation: With this mechanism, clients are to generate CSRs in CRMF format, and submit the requests to the CA (with proper KRA setup) for enrollment and key archival. See the Creating a CSR Using CRMFPopClient section in the Red Hat Certificate System Administration Guide.
Server-side key generation: With this mechanism, the properly equipped certificate enrollment profiles would trigger the PKI keys to be generated on KRA and thereby optionally archived along with newly issued certificates. See Generating CSRs Using Server-Side Key Generation.

The KRA automatically archives private encryption keys if archiving is configured.

The KRA stores private encryption keys in a secure key repository; each key is encrypted and stored as a key record and is given a unique key identifier.

The archived copy of the key remains wrapped with the KRA's storage key. It can be decrypted, or unwrapped, only by using the corresponding private key pair of the storage certificate. A combination of one or more key recovery (or KRA) agents' certificates authorizes the KRA to complete the key recovery to retrieve its private storage key and use it to decrypt/recover an archived private key. See Section 16.3.1, “Configuring Agent-Approved Key Recovery in the Command Line”.

The KRA indexes stored keys by key number, owner name, and a hash of the public key, allowing for highly efficient searching. The key recovery agents have the privilege to insert, delete, and search for key records.

When the key recovery agents search by the key ID, only the key that corresponds to that ID is returned.
When the agents search by username, all stored keys belonging to that owner are returned.
When the agents search by the public key in a certificate, only the corresponding private key is returned.

When a Certificate Manager receives a certificate request that contains the key archival option, it automatically forwards the request to the KRA to archive the encryption key. The private key is encrypted by the transport key, and the KRA receives the encrypted copy and stores the key in its key repository. To archive the key, the KRA uses two special key pairs:

A transport key pair and corresponding certificate.
A storage key pair.

Figure 2.2, “How the Key Archival Process Works in Client-Side Key Generation” illustrates how the key archival process occurs when an end entity requests a certificate in the case of client-side key generation.

Figure 2.2. How the Key Archival Process Works in Client-Side Key Generation

The client generates a CRMF request and submits it through the CA’s enrollment portal.
1. The client’s private key is wrapped within the CRMF request and can only be unwrapped by the KRA.
Detecting that it’s a CRMF request with key archival option, CA forwards the request to KRA for private key archival.
The KRA decrypts / unwraps the user private key, and after confirming that the private key corresponds to the public key, the KRA encrypts / wraps it again before storing it in its internal LDAP database.
Once the private encryption key has been successfully stored, the KRA responds to CA confirming that the key has been successfully archived.
The CA sends the request down its Enrollment Profile Framework for certificate information content creation as well as validation. When everything passes, it then issues the certificate and sends it back to the end entity in its response.

2.4.5.2. Recovering Keys

The KRA supports agent-initiated key recovery. Agent-initiated recovery is when designated recovery agents use the key recovery form on the KRA agent services portal to process and approve key recovery requests. With the approval of a specified number of agents, an organization can recover keys when the key's owner is unavailable or when keys have been lost.

Through the KRA agent services portal, key recovery agents can collectively authorize and retrieve private encryption keys and associated certificates into a PKCS #12 package, which can then be imported into the client.

In key recovery authorization, one of the key recovery agents informs all required recovery agents about an impending key recovery. All recovery agents access the KRA key recovery portal. One of the agents initiates the key recovery process. The KRA returns a notification to the agent includes a recovery authorization reference number identifying the particular key recovery request that the agent is required to authorize. Each agent uses the reference number and authorizes key recovery separately.

KRA supports Asynchronous recovery, meaning that each step of the recovery process — the initial request and each subsequent approval or rejection — is stored in the KRA's internal LDAP database, under the key entry. The status data for the recovery process can be retrieved even if the original browser session is closed or the KRA is shut down. Agents can search for the key to recover, without using a reference number.

This asynchronous recovery option is illustrated in Figure 2.3, “Asynchronous Recovery”.

Figure 2.3. Asynchronous Recovery

The KRA informs the agent who initiated the key recovery process of the status of the authorizations.

When all of the authorizations are entered, the KRA checks the information. If the information presented is correct, it retrieves the requested key and returns it along with the corresponding certificate in the form of a PKCS #12 package to the agent who initiated the key recovery process.

Warning

The PKCS #12 package contains the encrypted private key. To minimize the risk of key compromise, the recovery agent must use a secure method to deliver the PKCS #12 package and password to the key recipient. The agent should use a good password to encrypt the PKCS #12 package and set up an appropriate delivery mechanism.

The key recovery agent scheme configures the KRA to recognize to which group the key recovery agents belong and specifies how many of these recovery agents are required to authorize a key recovery request before the archived key is restored.

Important

The above information refers to using a web browser, such as Firefox. However, functionality critical to KRA usage is no longer included in Firefox version 31.6 that was released on Red Hat Enterprise Linux 7 platforms. In such cases, it is necessary to use the pki utility to replicate this behavior. For more information, see the pki(1) and pki-key(1) man pages or run CRMFPopClient --help and man CMCRequest.

Apart from storing asymmetric keys, KRA can also store symmetric keys or secrets similar to symmetric keys, such as volume encryption secrets, or even passwords and passphrases. The pki utility supports options that enable storing and retrieving these other types of secrets.

2.4.5.3. KRA Transport Key Rotation

KRA transport rotation allows for seamless transition between CA and KRA subsystem instances using a current and a new transport key. This allows KRA transport keys to be periodically rotated for enhanced security by allowing both old and new transport keys to operate during the time of the transition; individual subsystem instances take turns being configured while other clones continue to serve with no downtime.

In the KRA transport key rotation process, a new transport key pair is generated, a certificate request is submitted, and a new transport certificate is retrieved. The new transport key pair and certificate have to be included in the KRA configuration to provide support for the second transport key. Once KRA supports two transport keys, administrators can start transitioning CAs to the new transport key. KRA support for the old transport key can be removed once all CAs are moved to the new transport key.

To configure KRA transport key rotation:

Generate a new KRA transport key and certificate
Transfer the new transport key and certificate to KRA clones
Update the CA configuration with the new KRA transport certificate
Update the KRA configuration to use only the new transport key and certificate

After this, the rotation of KRA transport certificates is complete, and all the affected CAs and KRAs use the new KRA certificate only. For more information on how to perform the above steps, see the procedures below.

Generating the new KRA transport key and certificate

Request the KRA transport certificate.
1. Stop the KRA:
```
# systemctl stop pki-tomcatd@pki-kra.service
```
  OR (if using the nuxwdog watchdog)
```
# systemctl stop pki-tomcatd-nuxwdog@pki-kra.service
```
2. Go to the KRA NSS database directory:
```
# cd /etc/pki/pki-kra/alias
```
3. Create a subdirectory and save all the NSS database files into it. For example:
```
mkdir nss_db_backup
cp *.db nss_db_backup
```
4. Create a new request by using the PKCS10Client utility. For example:
```
# PKCS10Client -p password -d '.' -o 'req.txt' -n 'CN=KRA Transport 2 Certificate,O=example.com Security Domain'
```
  Alternatively, use the certutil utility. For example:
```
# certutil -d . -R -k rsa -g 2048 -s 'CN=KRA Transport 2 Certificate,O=example.com Security Domain' -f password-file -a -o transport-certificate-request-file
```
5. Submit the transport certificate request on the Manual Data Recovery Manager Transport Certificate Enrollment page of the CA End-Entity page.
6. Wait for the agent approval of the submitted request to retrieve the certificate by checking the request status on the End-Entity retrieval page.
Approve the KRA transport certificate through the CA Agent Services interface.
Retrieve the KRA transport certificate.
1. Go to the KRA NSS database directory:
```
# cd /etc/pki/pki-kra/alias
```
2. Wait for the agent approval of the submitted request to retrieve the certificate by checking the request status on the End-Entity retrieval page.
3. Once the new KRA transport certificate is available, paste its Base64-encoded value into a text file, for example a file named cert-serial_number.txt. Do not include the header (-----BEGIN CERTIFICATE-----) or the footer (-----END CERTIFICATE-----).

Import the KRA transport certificate.

Go to the KRA NSS database directory:
```
# cd /etc/pki/pki-kra/alias
```

Import the transport certificate into the KRA NSS database:

# certutil -d . -A -n 'transportCert-serial_number cert-pki-kra KRA' -t 'u,u,u' -a -i cert-serial_number.txt

Update the KRA transport certificate configuration.
1. Go to the KRA NSS database directory:
```
# cd /etc/pki/pki-kra/alias
```
2. Verify that the new KRA transport certificate is imported:
```
# certutil -d . -L
# certutil -d . -L -n 'transportCert-serial_number cert-pki-kra KRA'
```
3. Open the /var/lib/pki/pki-kra/kra/conf/CS.cfg file and add the following line:
```
kra.transportUnit.newNickName=transportCert-serial_number cert-pki-kra KRA
```

Propagating the new transport key and certificate to KRA clones

Start the KRA:

# systemctl start pki-tomcatd@pki-kra.service

or (if using the nuxwdog watchdog)

# systemctl start pki-tomcatd-nuxwdog@pki-kra.service

Extract the new transport key and certificate for propagation to clones.

Go to the KRA NSS database directory:
```
# cd /etc/pki/pki-kra/alias
```

Stop the KRA:

# systemctl stop pki-tomcatd@pki-kra.service

or (if using the nuxwdog watchdog)

# systemctl stop pki-tomcatd-nuxwdog@pki-kra.service

Verify that the new KRA transport certificate is present:

# certutil -d . -L
# certutil -d . -L -n 'transportCert-serial_number cert-pki-kra KRA'

Export the KRA new transport key and certificate:

# pk12util -o transport.p12 -d . -n 'transportCert-serial_number cert-pki-kra KRA'

Verify the exported KRA transport key and certificate:
```
# pk12util -l transport.p12
```

Perform these steps on each KRA clone:
1. Copy the transport.p12 file, including the transport key and certificate, to the KRA clone location.
2. Go to the clone NSS database directory:
```
# cd /etc/pki/pki-kra/alias
```
3. Stop the KRA clone:
```
# systemctl stop pki-tomcatd@pki-kra.service
```
  or (if using the nuxwdog watchdog)
```
# systemctl stop pki-tomcatd-nuxwdog@pki-kra.service
```
4. Check the content of the clone NSS database:
```
# certutil -d . -L
```
5. Import the new transport key and certificate of the clone:
```
# pk12util -i transport.p12 -d .
```
6. Add the following line to the /var/lib/pki/pki-kra/kra/conf/CS.cfg file on the clone:
```
kra.transportUnit.newNickName=transportCert-serial_number cert-pki-kra KRA
```
7. Start the KRA clone:
```
# systemctl start pki-tomcatd@pki-kra.service
```
  or (if using the nuxwdog watchdog)
```
# systemctl start pki-tomcatd-nuxwdog@pki-kra.service
```

Updating the CA configuration with the new KRA transport certificate

Format the new KRA transport certificate for inclusion in the CA.
1. Obtain the cert-serial_number.txt KRA transport certificate file created when retrieving the KRA transport certificate in the previous procedure.
2. Convert the Base64-encoded certificate included in cert-serial_number.txt to a single-line file:
```
# tr -d '\n' < cert-serial_number.txt > cert-one-line-serial_number.txt
```
Do the following for the CA and all its clones corresponding to the KRA above:
1. Stop the CA:
```
# systemctl stop pki-tomcatd@pki-ca.service
```
  or (if using the nuxwdog watchdog)
```
# systemctl stop pki-tomcatd-nuxwdog@pki-ca.service
```
2. In the /var/lib/pki/pki-ca/ca/conf/CS.cfg file, locate the certificate included in the following line:
```
ca.connector.KRA.transportCert=certificate
```
  Replace that certificate with the one contained in cert-one-line-serial_number.txt.
3. Start the CA:
```
# systemctl start pki-tomcatd@pki-ca.service
```
  or (if using the nuxwdog watchdog)
```
# systemctl start pki-tomcatd-nuxwdog@pki-ca.service
```

Note

While the CA and all its clones are being updated with the new KRA transport certificate, the CA instances that have completed the transition use the new KRA transport certificate, and the CA instances that have not yet been updated continue to use the old KRA transport certificate. Because the corresponding KRA and its clones have already been updated to use both transport certificates, no downtime occurs.

Updating the KRA configuration to use only the new transport key and certificate

For the KRA and each of its clones, do the following:

Go to the KRA NSS database directory:
```
# cd /etc/pki/pki-kra/alias
```

Stop the KRA:

# systemctl stop pki-tomcatd@pki-kra.service

or (if using the nuxwdog watchdog)

# systemctl stop pki-tomcatd-nuxwdog@pki-kra.service

Verify that the new KRA transport certificate is imported:

# certutil -d . -L
# certutil -d . -L -n 'transportCert-serial_number cert-pki-kra KRA'

Open the /var/lib/pki/pki-kra/kra/conf/CS.cfg file, and look for the nickName value included in the following line:
```
kra.transportUnit.nickName=transportCert cert-pki-kra KRA
```
Replace the nickName value with the newNickName value included in the following line:
```
kra.transportUnit.newNickName=transportCert-serial_number cert-pki-kra KRA
```
As a result, the CS.cfg file includes this line:
```
kra.transportUnit.nickName=transportCert-serial_number cert-pki-kra KRA
```

Remove the following line from /var/lib/pki/pki-kra/kra/conf/CS.cfg:

kra.transportUnit.newNickName=transportCert-serial_number cert-pki-kra KRA

Start the KRA:

# systemctl start pki-tomcatd@pki-kra.service

or (if using the nuxwdog watchdog)

# systemctl start pki-tomcatd-nuxwdog@pki-kra.service

2.5. Smart Card Token Management with Certificate System

A smart card is a hardware cryptographic device containing cryptographic certificates and keys. It can be employed by the user to participate in operations such as secure website access and secure mail. It can also serve as an authentication device to log in to various operating systems such as Red Hat Enterprise Linux. The management of these cards or tokens throughout their entire lifetime in service is accomplished by the Token Management System (TMS).

A TMS environment requires a Certificate Authority (CA), Token Key Service (TKS), and Token Processing System (TPS), with an optional Key Recovery Authority (KRA) for server-side key generation and key archival and recovery. Online Certificate Status Protocol (OCSP) can also be used to work with the CA to serve online certificate status requests. This chapter provides an overview of the TKS and TPS systems, which provide the smart card management functions of Red Hat Certificate System, as well as Enterprise Security Client (ESC), that works with TMS from the user end.

Figure 2.4. How the TMS Manages Smart Cards

2.5.1. Token Key Service (TKS)

The Token Key Service (TKS) is responsible for managing one or more master keys. It maintains the master keys and is the only entity within the TMS that has access to the key materials. In an operational environment, each valid smart card token contains a set of symmetric keys that are derived from both the master key and the ID that is unique to the card (CUID).

Initially, a default (unique only per manufacturer master key) set of symmetric keys is initialized on each smart card by the manufacturer. This default set should be changed at the deployment site by going through a Key Changeover operation to generate the new master key on TKS. As the sole owner to the master key, when given the CUID of a smart card, TKS is capable of deriving the set of symmetric keys residing on that particular smart card, which would then allow TKS to establish a session-based Secure Channel for secure communication between TMS and each individual smart card.

Note

Because of the sensitivity of the data that the TKS manages, the TKS should be set behind the firewall with restricted access.

2.5.1.1. Master Keys and Key Sets

The TKS supports multiple smart card key sets. Each smart card vendor creates different default (developer) static key sets for their smart card token stocks, and the TKS is equipped with the static key set (per manufacturer) to kickstart the format process of a blank token.

During the format process of a blank smart card token, a Java applet and the uniquely derived symmetric key set are injected into the token. Each master key (in some cases referred to as keySet) that the TKS supports is to have a set of entries in the TKS configuration file (CS.cfg). Each TPS profile contains a configuration to direct its enrollment to the proper TKS keySet for the matching key derivation process that would essentially be responsible for establishing the Secure Channel secured by a set of session-specific keys between TMS and the smart card token.

On TKS, master keys are defined by named keySets for references by TPS. On TPS, depending on the enrollment type (internal or external registration), The keySet is either specified in the TPS profile, or determined by the keySet Mapping Resolver.

2.5.1.2. Key Ceremony (Shared Key Transport)

A Key Ceremony is a process for transporting highly sensitive keys in a secure way from one location to another. In one scenario, in a highly secure deployment environment, the master key can be generated in a secure vault with no network to the outside. Alternatively, an organization might want to have TKS and TPS instances on different physical machines. In either case, under the assumption that no one single person is to be trusted with the key, Red Hat Certificate System TMS provides a utility called tkstool to manage the secure key transportation.

2.5.1.3. Key Update (Key Changeover)

When Global Platform-compliant smart cards are created at the factory, the manufacturer will burn a set of default symmetric keys onto the token. The TKS is initially configured to use these symmetric keys (one KeySet entry per vendor in the TKS configuration). However, since these symmetric keys are not unique to the smart cards from the same stock, and because these are well-known keys, it is strongly encouraged to replace these symmetric keys with a set that is unique per token, not shared by the manufacturer, to restrict the set of entities that can manipulate the token.

The changing over of the keys takes place with the assistance of the Token Key Service subsystem. One of the functions of the TKS is to oversee the Master Keys from which the previously discussed smart card token keys are derived. There can be more than one master key residing under the control of the TKS.

Important

When this key changeover process is done on a token, the token may become unusable in the future since it no longer has the default key set enabled. The key is essentially only as good as long as the TPS and TKS system that provisioned the token is valid. Because of this, it is essential to keep all the master keys, even if any of them are outdated.

You can disable the old master keys in TKS for better control, but do not delete them unless disabled tokens are part of your plan. There is support to revert the token keys back to the original key set, which is viable if the token is to be reused again in some sort of a testing scenario.

2.5.1.4. APDUs and Secure Channels

The Red Hat Certificate System Token Management System (TMS) supports the GlobalPlatform smart card specification, in which the Secure Channel implementation is done with the Token Key System (TKS) managing the master key and the Token Processing System (TPS) communicating with the smart card (tokens) with Application Protocol Data Units (APDUs).

There are two types of APDUs:

Command APDUs, sent by the TPS to smart cards
Response APDUs, sent by smart cards to the TPS as response to command APDUs

The initiation of the APDU commands may be triggered when clients take action and connect to the Certificate System server for requests. A secure channel begins with an InitializeUpdate APDU sent from TPS to the smart card token, and is fully established with the ExternalAuthenticate APDU. Then, both the token and TMS would have established a set of shared secrets, called session keys, which are used to encrypt and authenticate the communication. This authenticated and encrypted communication channel is called Secure Channel.

Because TKS is the only entity that has access to the master key which is capable of deriving the set of unique symmetric on-token smart card keys, the Secure Channel provides the adequately safeguarded communication between TMS and each individual token. Any disconnection of the channel will require reestablishment of new session keys for a new channel.

2.5.2. Token Processing System (TPS)

The Token Processing System (TPS) is a registration authority for smart card certificate enrollment. It acts as a conduit between the user-centered Enterprise Security Client (ESC), which interacts with client side smart card tokens, and the Certificate System back end subsystems, such as the Certificate Authority (CA) and the Key Recovery Authority (KRA).

In TMS, the TPS is required in order to manage smart cards, as it is the only TMS entity that understands the APDU commands and responses. TPS sends commands to the smart cards to help them generate and store keys and certificates for a specific entity, such as a user or device. Smart card operations go through the TPS and are forwarded to the appropriate subsystem for action, such as the CA to generate certificates or the KRA to generate, archive, or recover keys.

2.5.2.1. Coolkey Applet

Red Hat Certificate System includes the Coolkey Java applet, written specifically to run on TMS-supported smart card tokens. The Coolkey applet connects to a PKCS#11 module that handles the certificate and key related operations. During a token format operation, this applet is injected onto the smart card token using the Secure Channel protocol, and can be updated per configuration.

2.5.2.2. Token Operations

The TPS in Red Hat Certificate System is available to provision smart cards on the behalf of end users of the smart cards. The Token Processing System provides support for the following major token operations:

Token Format - The format operation is responsible for installing the proper Coolkey applet onto the token. The applet provides a platform where subsequent cryptographic keys and certificates can be later placed.
Token Enrollment - The enrollment operation results in a smart card populated with required cryptographic keys and cryptographic certificates. This material allows the user of the smart card to participate in operations such as secure web site access and secure mail. Two types of enrollments are supported, which is configured globally:
- Internal Registration - Enrollment by TPS profiles determined by the profile Mapping Resolver.
- External Registration - Enrollment by TPS profiles determined by the entries in the user’s LDAP record.
Token PIN Reset - The token PIN reset operation allows the user of the token to specify a new PIN that is used to log into the token, making it available for performing cryptographic operations.

The following other operations can be considered supplementary or inherent operations to the main ones listed above. They can be triggered per relevant configuration or by the state of the token.

Key Generation - Each PKI certificate is comprised of a public/private key pair. In Red Hat Certificate System, the generation of the keys can be done in two ways, depending on the TPS profile configuration:
- Token Side Key Generation - The PKI key pairs are generated on the smart card token. Generating the key pairs on the token side does not allow for key archival.
- Server Side Key Generation - The PKI key pairs are generated on the TMS server side. The key pairs are then sent back to the token using Secure Channel. Generating the key pairs on the server side allows for key archival.
Certificate Renewal - This operation allows a previously enrolled token to have the certificates currently on the token reissued while reusing the same keys. This is useful in situations where the old certificates are due to expire and you want to create new ones but maintain the original key material.
Certificate Revocation - Certificate revocation can be triggered based on TPS profile configuration or based on token state.
Normally, only the CA which issued a certificate can revoke it, which could mean that retiring a CA would make it impossible to revoke certain certificates. However, it is possible to route revocation requests for tokens to the retired CA while still routing all other requests such as enrollment to a new, active CA. This mechanism is called Revocation Routing.
Token Key Changeover - The key changeover operation, triggered by a format operation, results in the ability to change the internal keys of the token from the default developer key set to a new key set controlled by the deployer of the Token Processing System. This is usually done in any real deployment scenario since the developer key set is better suited to testing situations.
Applet Update - During the course of a TMS deployment, the Coolkey smart card applet can be updated or downgraded if required.

2.5.2.3. TPS Profiles

The Certificate System Token Processing System subsystem facilitates the management of smart card tokens. Tokens are provisioned by the TPS such that they are taken from a blank state to either a Formatted or Enrolled condition. A Formatted token is one that contains the CoolKey applet supported by TPS, while an Enrolled token is personalized (a process called binding) to an individual with the requisite certificates and cryptographic keys. This fully provisioned token is ready to use for crytptographic operations.

The TPS can also manage Profiles. The notion of a token Profile is related to:

The steps taken to Format or Enroll a token.
The attributes contained within the finished token after the operation has been successfully completed.

The following list contains some of the quantities that make up a unique token profile:

How does the TPS connect to the user's authentication LDAP database?
Will user authentication be required for this token operation? If so, what authentication manager will be used?
How does the TPS connect to a Certificate System CA from which it will obtain certificates?
How are the private and public keys generated on this token? Are they generated on the token side or on the server side?
What key size (in bits) is to be used when generating private and public keys?
Which certificate enrollment profile (provisioned by the CA) is to be used to generate the certificates on this token?
Note
This setting will determine the final structure of the certificates to be written to the token. Different certificates can be created for different uses, based on extensions included in the certificate. For example, one certificate can specialize in data encryption, and another one can be used for signature operations.
What version of the Coolkey applet will be required on the token?
How many certificates will be placed on this token for an enrollment operation?

These above and many others can be configured for each token type or profile. A full list of available configuration options is available in the Red Hat Certificate System Administration Guide.

Another question to consider is how a given token being provisioned by a user will be mapped to an individual token profile. There are two types of registration:

Internal Registration - In this case, the TPS profile (tokenType) is determined by the profile Mapping Resolver. This filter-based resolver can be configured to take any of the data provided by the token into account and determine the target profile.
External Registration - When using external registration, the profile (in name only - actual profiles are still defined in the TPS in the same fashion as those used by the internal registration) is specified in each user's LDAP record, which is obtained during authentication. This allows the TPS to obtain key enrollment and recovery information from an external registration Directory Server where user information is stored. This gives you the control to override the enrollment, revocation, and recovery policies that are inherent to the TPS internal registration mechanism. The user LDAP record attribute names relevant to external registration are configurable.
External registration can be useful when the concept of a "group certificate" is required. In that case, all users within a group can have a special record configured in their LDAP profiles for downloading a shared certificate and keys.

The registration to be used is configured globally per TPS instance.

2.5.2.4. Token Database

The Token Processing System makes use of the LDAP token database store, which is used to keep a list of active tokens and their respective certificates, and to keep track of the current state of each token. A brand new token is considered Uninitialized, while a fully enrolled token is Enrolled. This data store is constantly updated and consulted by the TPS when processing tokens.

2.5.2.4.1. Token States and Transitions

The Token Processing System stores states in its internal database in order to determine the current token status as well as actions which can be performed on the token.

2.5.2.4.1.1. Token States

The following table lists all possible token states:

Table 2.9. Possible Token States
Name	Code	Label
FORMATTED	0	Formatted (uninitialized)
DAMAGED	1	Physically damaged
PERM_LOST	2	Permanently lost
SUSPENDED	3	Suspended (temporarily lost)
ACTIVE	4	Active
TERMINATED	6	Terminated
UNFORMATTED	7	Unformatted

The command line interface displays token states using the Name listed above. The graphical interface uses the Label instead.

Note

The above table contains no state with code 5, which previously belonged to a state that was removed.

2.5.2.4.1.2. Token State Transitions Done Using the Graphical or Command Line Interface

Each token state has a limited amount of next states it can transition into. For example, a token can change state from FORMATTED to ACTIVE or DAMAGED, but it can never transition from FORMATTED to UNFORMATTED.

Furthermore, the list of states a token can transition into is different depending on whether the transition is triggered manually using a command line or the graphical interface, or automatically using a token operation. The list of allowed manual transitions is stored in the tokendb.allowedTransitions property, and the tps.operations.allowedTransitions property controls allowed transitions triggered by token operations.

The default configurations for both manual and token operation-based transitions are stored in the /usr/share/pki/tps/conf/CS.cfg configuration file.

2.5.2.4.1.2.1. Token State Transitions Using the Command Line or Graphical Interface

All possible transitions allowed in the command line or graphical interface are described in the TPS configuration file using the tokendb.allowedTransitions property:

tokendb.allowedTransitions=0:1,0:2,0:3,0:6,3:2,3:6,4:1,4:2,4:3,4:6,6:7

The property contains a comma-separated list of transitions. Each transition is written in the format of <current code>:<new code>. The codes are described in Table 2.9, “Possible Token States”. The default configuration is preserved in /usr/share/pki/tps/conf/CS.cfg.

The following table describes each possible transition in more detail:

Table 2.10. Possible Manual Token State Transitions
Transition	Current State	Next State	Description
0:1	FORMATTED	DAMAGED	This token has been physically damaged.
0:2	FORMATTED	PERM_LOST	This token has been permanently lost.
0:3	FORMATTED	SUSPENDED	This token has been suspended (temporarily lost).
0:6	FORMATTED	TERMINATED	This token has been terminated.
3:2	SUSPENDED	PERM_LOST	This suspended token has been permanently lost.
3:6	SUSPENDED	TERMINATED	This suspended token has been terminated.
4:1	ACTIVE	DAMAGED	This token has been physically damaged.
4:2	ACTIVE	PERM_LOST	This token has been permanently lost.
4:3	ACTIVE	SUSPENDED	This token has been suspended (temporarily lost).
4:6	ACTIVE	TERMINATED	This token has been terminated.
6:7	TERMINATED	UNFORMATTED	Reuse this token.

The following transitions are generated automatically depending on the token's original state. If a token was originally FORMATTED and then became SUSPENDED, it can only return to the FORMATTED state. If a token was originally ACTIVE and then became SUSPENDED, it can only return to the ACTIVE state.

Table 2.11. Token State Transitions Triggered Automatically
Transition	Current State	Next State	Description
3:0	SUSPENDED	FORMATTED	This suspended (temporarily lost) token has been found.
3:4	SUSPENDED	ACTIVE	This suspended (temporarily lost) token has been found.

2.5.2.4.1.3. Token State Transitions using Token Operations

All possible transitions that can be done using token operations are described in the TPS configuration file using the tokendb.allowedTransitions property:

tps.operations.allowedTransitions=0:0,0:4,4:4,4:0,7:0

The following table describes each possible transition in more detail:

Table 2.12. Possible Token State Transitions using Token Operations
Transition	Current State	Next State	Description
0:0	FORMATTED	FORMATTED	This allows reformatting a token or upgrading applet/key in a token.
0:4	FORMATTED	ACTIVE	This allows enrolling a token.
4:4	ACTIVE	ACTIVE	This allows re-enrolling an active token. May be useful for external registration.
4:0	ACTIVE	FORMATTED	This allows formatting an active token.
7:0	UNFORMATTED	FORMATTED	This allows formatting a blank or previously used token.

2.5.2.4.1.4. Token State and Transition Labels

The default labels for token states and transitions are stored in the /usr/share/pki/tps/conf/token-states.properties configuration file. By default, the file has the following contents:

# Token states
UNFORMATTED         = Unformatted
FORMATTED           = Formatted (uninitialized)
ACTIVE              = Active
SUSPENDED           = Suspended (temporarily lost)
PERM_LOST           = Permanently lost
DAMAGED             = Physically damaged
TEMP_LOST_PERM_LOST = Temporarily lost then permanently lost
TERMINATED          = Terminated

# Token state transitions
FORMATTED.DAMAGED        = This token has been physically damaged.
FORMATTED.PERM_LOST      = This token has been permanently lost.
FORMATTED.SUSPENDED      = This token has been suspended (temporarily lost).
FORMATTED.TERMINATED     = This token has been terminated.
SUSPENDED.ACTIVE         = This suspended (temporarily lost) token has been found.
SUSPENDED.PERM_LOST      = This suspended (temporarily lost) token has become permanently lost.
SUSPENDED.TERMINATED     = This suspended (temporarily lost) token has been terminated.
SUSPENDED.FORMATTED      = This suspended (temporarily lost) token has been found.
ACTIVE.DAMAGED           = This token has been physically damaged.
ACTIVE.PERM_LOST         = This token has been permanently lost.
ACTIVE.SUSPENDED         = This token has been suspended (temporarily lost).
ACTIVE.TERMINATED        = This token has been terminated.
TERMINATED.UNFORMATTED   = Reuse this token.

2.5.2.4.1.5. Customizing Allowed Token State Transitions

To customize the list of token state transition, edit the following properties in /var/lib/pki/instance_name/tps/conf/CS.cfg:

tokendb.allowedTransitions to customize the list of allowed transitions performed using the command line or graphical interface
tps.operations.allowedTransitions to customize the list of allowed transitions using token operations

Transitions can be removed from the default list if necessary, but new transitions cannot be added unless they were in the default list. The defaults are stored in /usr/share/pki/tps/conf/CS.cfg.

2.5.2.4.1.6. Customizing Token State and Transition Labels

To customize token state and transition labels, copy the default /usr/share/pki/tps/conf/token-states.properties into your instance folder (/var/lib/pki/instance_name/tps/conf/CS.cfg), and change the labels listed inside as needed.

Changes will be effective immediately, the server does not need to be restarted. The TPS user interface may require a reload.

To revert to default state and label names, delete the edited token-states.properties file from your instance folder.

2.5.2.4.1.7. Token Activity Log

Certain TPS activities are logged. Possible events in the log file are listed in the table below.

Table 2.13. TPS Activity Log Events
Activity	Description
add	A token was added.
format	A token was formatted.
enrollment	A token was enrolled.
recovery	A token was recovered.
renewal	A token was renewed.
pin_reset	A token PIN was reset.
token_status_change	A token status was changed using the command line or graphical interface.
token_modify	A token was modified.
delete	A token was deleted.
cert_revocation	A token certificate was revoked.
cert_unrevocation	A token certificate was unrevoked.

2.5.2.4.2. Token Policies

In case of internal registration, each token can be governed by a set of token policies. The default policies are:

RE_ENROLL=YES;RENEW=NO;FORCE_FORMAT=NO;PIN_RESET=NO;RESET_PIN_RESET_TO_NO=NO;RENEW_KEEP_OLD_ENC_CERTS=YES

All TPS operations under internal registration are subject to the policies specified in the token's record. If no policies are specified for a token, the TPS uses the default set of policies.

2.5.2.5. Mapping Resolver

The Mapping Resolver is an extensible mechanism used by the TPS to determine which token profile to assign to a specific token based on configurable criteria. Each mapping resolver instance can be uniquely defined in the configuration, and each operation can point to various defined mapping resolver instance.

Note

The mapping resolver framework provides a platform for writing custom plug-ins. However instructions on how to write a plug-in is outside the scope of this document.

FilterMappingResolver is the only mapping resolver implementation provided with the TPS by default. It allows you to define a set of mappings and a target result for each mapping. Each mapping contains a set of filters, where:

If the input filter parameters pass all filters within a mapping, the target value is assigned.
If the input parameters fail a filter, that mapping is skipped and the next one in order is tried.
If a filter has no specified value, it always passes.
If a filter does have a specified value, then the input parameters must match exactly.
The order in which mappings are defined is important. The first mapping which passes is considered resolved and is returned to the caller.

The input filter parameters are information received from the smart card token with or without extensions. They are run against the FilterMappingResolver according to the above rules. The following input filter parameters are supported by FilterMappingResolver:

appletMajorVersion - The major version of the Coolkey applet on the token.
appletMinorVersion - The minor version of the Coolkey applet on the token.
keySet or tokenType
- keySet - can be set as an extension in the client request. Must match the value in the filter if the extension is specified. The keySet mapping resolver is meant for determining keySet value when using external registration. The Key Set Mapping Resolver is necessary in the external registration environment when multiple key sets are supported (for example, different smart card token vendors). The keySet value is needed for identifying the master key on TKS, which is crucial for establishing Secure Channel. When a user's LDAP record is populated with a set tokenType (TPS profile), it does not know which card will end up doing the enrollment, and therefore keySet cannot be predetermined. The keySetMappingResolver helps solve the issue by allowing the keySet to be resolved before authentication.
- tokenType - okenType can be set as an extension in the client request. It must match the value in the filter if the extension is specified. tokenType (also referred to as TPS Profile) is determined at this time for the internal registration environment.
tokenATR - The token's Answer to Reset (ATR).
tokenCUID - "start" and "end" define the range the Card Unique IDs (CUID) of the token must fall in to pass this filter.

2.5.2.6. TPS Roles

The TPS supports the following roles by default:

TPS Administrator - this role is allowed to:
- Manage TPS tokens
- View TPS certificates and activities
- Manage TPS users and groups
- Change general TPS configuration
- Manage TPS authenticators and connectors
- Configure TPS profiles and profile mappings
- Configure TPS audit logging
TPS Agent - this role is allowed to:
- Configure TPS tokens
- View TPS certificates and activities
- Change the status of TPS profiles
TPS Operator - this role is allowed to:
- View TPS tokens, certificates, and activities

2.5.3. TKS/TPS Shared Secret

During TMS installation, a shared symmetric key is established between the Token Key Service and the Token Processing System. The purpose of this key is to wrap and unwrap session keys which are essential to Secure Channels.

Note

The shared secret key is currently only kept in a software cryptographical database. There are plans to support keeping the key on a Hardware Security Module (HSM) devices in a future release of Red Hat Certificate System. Once this functionality is implemented, you will be instructed to run a Key Ceremony using tkstool to transfer the key to the HSM.

2.5.4. Enterprise Security Client (ESC)

The Enterprise Security Client is an HTTP client application, similar to a web browser, that communicates with the TPS and handles smart card tokens from the client side. While an HTTPS connection is established between the ESC and the TPS, an underlying Secure Channel is also established between the token and the TMS within each TLS session.

2.6. Red Hat Certificate System Services

Certificate System has a number of different features for administrators to use which makes it easier to maintain the individual subsystems and the PKI as a whole.

2.6.1. Notifications

When a particular event occurs, such as when a certificate is issued or revoked, then a notification can be sent directly to a specified email address. The notification framework comes with default modules that can be enabled and configured.

2.6.2. Jobs

Automated jobs run at defined intervals.

2.6.3. Logging

The Certificate System and each subsystem produce extensive system and error logs that record system events so that the systems can be monitored and debugged. All log records are stored in the local file system for quick retrieval. Logs are configurable, so logs can be created for specific types of events and at the required logging level.

Certificate System allows logs to be signed digitally before archiving them or distributing them for auditing. This feature enables log files to be checked for tampering after being signed.

2.6.4. Auditing

The Certificate System maintains audit logs for all events, such as requesting, issuing and revoking certificates and publishing CRLs. These logs are then signed. This allows authorized access or activity to be detected. An outside auditor can then audit the system if required. The assigned auditor user account is the only account which can view the signed audit logs. This user's certificate is used to sign and encrypt the logs. Audit logging is configured to specify the events that are logged.

2.6.5. Self-Tests

The Certificate System provides the framework for system self-tests that are automatically run at startup and can be run on demand. A set of configurable self-tests are already included with the Certificate System.

2.6.6. Users, Authorization, and Access Controls

Certificate System users can be assigned to groups, which are also known as roles, and they then have the privileges of whichever group they are members. A user only has privileges for the instance of the subsystem in which the user is created and the privileges of the group to which the user is a member.

Authentication is the means that Certificate System subsystems use to verify the identity of clients, whether they are authenticating to a certificate profile or to one of the services interfaces. There are a number of different ways for a client to perform authentication, including simple user name/password, SSL/TLS client authentication, LDAP authentication, NIS authentication, or CMC. Authentication can be performed for any access to the subsystem; for certificate enrollments, for example, the profile defines how the requestor authenticates to the CA.

Once the client is identified and authenticated, then the subsystems perform an authorization check to determine what level of access to the subsystem that particular user is allowed.

Authorization is tied to group, or role, permissions, rather than directly to individual users. The Certificate System provides an authorization framework for creating groups and assigning access control to those groups. The default access control on preexisting groups can be modified, and access control can be assigned to individual users and IP addresses. Access points for authorization have been created for the major portions of the system, and access control rules can be set for each point.

2.6.6.1. Default Administrative Roles

Note

Red Hat Certificate System uses the words roles and groups interchangeably in the context of the permissions given to users.

The Certificate System is configured by default with three user types with different access levels to the system:

Administrators, who can perform any administrative or configuration task for a subsystem.
Agents, who perform PKI management tasks, like approving certificate requests, managing token enrollments, or recovering keys.
Auditors, who can view and configure audit logs.

Note

By default, for bootstrapping purposes, an administrative user processing both Administrator and Agent privileges is created during the Red Hat Certificate System instance creation, when running the pkispawn utility. This bootstrap administrator uses the caadmin user name by default but can be overridden by the pki_admin_uid parameter in the configuration file passed to the pkispawn command. The purpose of the bootstrap administrator is to create the first administrator and agent user. This operation requires the administrator privilege to mange user and groups, and the agent privilege to issue certificates.

2.6.6.2. Built-in Subsystem Trust Roles

Additionally, when a security domain is created, the CA subsystem which hosts the domain is automatically granted the special role of Security Domain Administrator, which gives the subsystem the ability to manage the security domain and the subsystem instances within it. Other security domain administrator roles can be created for the different subsystem instances. These special roles should not have actual users as members.

2.7. Cloning

2.7.1. About Cloning

Planning for high availability reduces unplanned outages and other problems by making one or more subsystem clones available. When a host machine goes down, the cloned subsystems can handle requests and perform services, taking over from the master (original) subsystem seamlessly and keeping uninterrupted service.

Using cloned subsystems also allows systems to be taken offline for repair, troubleshooting, or other administrative tasks without interrupting the services of the overall PKI system.

Note

All of the subsystems except the TPS can be cloned.

Cloning is one method of providing scalability to the PKI by assigning the same task, such as handling certificate requests, to separate instances on different machines. The internal databases for the master and its clones are replicated between each other, so the information about certificate requests or archived keys on one subsystem is available on all the others.

Typically, master and cloned instances are installed on different machines, and those machines are placed behind a load balancer. The load balancer accepts HTTP and HTTPS requests made to the Certificate System subsystems and directs those requests appropriately between the master and cloned instances. In the event that one machine fails, the load balancer transparently redirects all requests to the machine that is still running until the other machine is brought back online.

Figure 2.5. Cloning Example

The load balancer in front of a Certificate System subsystem is what provides the actual failover support in a high availability system. A load balancer can also provide the following advantages as part of a Certificate System subsystem:

DNS round-robin, a feature for managing network congestion that distributes load across several different servers.
Sticky SSL/TLS, which makes it possible for a user returning to the system to be routed the same host used previously.

Normally, when a system is cloned, the configuration servlet sets up the replication agreements between the internal LDAP databases. However, some users may want to establish and manage their own replication agreements. The pkispawn executable has been modified to allow this by adding a [Tomcat] section to the PKI instance override configuration file and adding the following two name=value pairs under that section:

[Tomcat]
pki_clone_setup_replication=False
pki_clone_reindex_data=False

Important

Data must be replicated before pkispawn is invoked when specifying this kind of installation.

2.7.2. Preparing Clones

You need to export certificates to a p12 file which can then be used while installing a clone subsystem. This command does not install or setup a clone subsystem, but prepares it for installation. Here is an example how to export subsystem certificates using the pki-server SUBSYSTEM-clone-prepare command.

Example 2.5. Exporting Subsystem Certificates

[root@pki1 ~]$ pki-server ca-clone-prepare --i topology-02-CA --pkcs12-file /tmp/caclone.p12 --pkcs12-password SECret.123
-----------------------------------------------------
Added certificate "subsystemCert cert-topology-02-CA"
-----------------------------------------------------
--------------------------------------------------------
Added certificate "caSigningCert cert-topology-02-CA CA"
--------------------------------------------------------
----------------------------------------------------------
Added certificate "ocspSigningCert cert-topology-02-CA CA"
----------------------------------------------------------
-----------------------------------------------------------
Added certificate "auditSigningCert cert-topology-02-CA CA"
-----------------------------------------------------------

You can verify that the exported p12 file contains the certificates. In the following example, the output of the pki pkcs12-cert-find returns four certificates:

[root@pki1 ~]$ pki pkcs12-cert-find --pkcs12-file /tmp/caclone.p12 --pkcs12-password SECret.123
---------------
4 entries found
---------------
Certificate ID: 4649cef11b90c78d126874b91654de98ded54073
Serial Number: 0x4
Nickname: subsystemCert cert-topology-02-CA
Subject DN: CN=Subsystem Certificate,OU=topology-02-CA,O=topology-02_Foobarmaster.org
Issuer DN: CN=CA Signing Certificate,OU=topology-02-CA,O=topology-02_Foobarmaster.org
Trust Flags: u,u,u
Has Key: true

Certificate ID: a304cf107abd79fbda06d887cd279fb02cefe438
Serial Number: 0x1
Nickname: caSigningCert cert-topology-02-CA CA
Subject DN: CN=CA Signing Certificate,OU=topology-02-CA,O=topology-02_Foobarmaster.org
Issuer DN: CN=CA Signing Certificate,OU=topology-02-CA,O=topology-02_Foobarmaster.org
Trust Flags: CTu,Cu,Cu
Has Key: true

Certificate ID: 4a09e057c1edfee40f412551db1959831abe117d
Serial Number: 0x2
Nickname: ocspSigningCert cert-topology-02-CA CA
Subject DN: CN=CA OCSP Signing Certificate,OU=topology-02-CA,O=topology-02_Foobarmaster.org
Issuer DN: CN=CA Signing Certificate,OU=topology-02-CA,O=topology-02_Foobarmaster.org
Trust Flags: u,u,u
Has Key: true

Certificate ID: 3f42f88026267f90f59631d38805cc60ee4c711a
Serial Number: 0x5
Nickname: auditSigningCert cert-topology-02-CA CA
Subject DN: CN=CA Audit Signing Certificate,OU=topology-02-CA,O=topology-02_Foobarmaster.org
Issuer DN: CN=CA Signing Certificate,OU=topology-02-CA,O=topology-02_Foobarmaster.org
Trust Flags: u,u,Pu
Has Key: true

With the exported p12 file, you can now set up a clone subsystem.

2.7.3. Cloning for CAs

Cloned instances have the exact same private keys as the master, so their certificates are identical. For CAs, that means that the CA signing certificates are identical for the original master CA and its cloned CAs. From the perspectives of clients, these look like a single CA.

Every CA, both cloned and master, can issue certificates and process revocation requests.

The main issue with managing replicated CAs is how to assign serial numbers to the certificates they issue. Different replicated CAs can have different levels of traffic, using serial numbers at different rates, and it is imperative that no two replicated CAs issue certificates with the same serial number. These serial number ranges are assigned and managed dynamically by using a shared, replicated entry that defines the ranges for each CA and the next available range to reassign when one CA range runs low.

The serial number ranges with cloned CAs are fluid. All replicated CAs share a common configuration entry which defines the next available range. When one CA starts running low on available numbers, it checks this configuration entry and claims the next range. The entry is automatically updated, so that the next CA gets a new range.

The ranges are defined in begin*Number and end*Number attributes, with separate ranges defined for requests and certificate serial numbers. For example:

 dbs.beginRequestNumber=1
 dbs.beginSerialNumber=1
 dbs.enableSerialManagement=true
 dbs.endRequestNumber=9980000
 dbs.endSerialNumber=ffe0000
 dbs.replicaCloneTransferNumber=5

Only one replicated CA can generate, cache, and publish CRLs; this is the CRL CA. CRL requests submitted to other replicated CAs are immediately redirected to the CRL CA. While other replicated CAs can revoke, display, import, and download CRLs previously generated by the CRL CA, synchronization problems might occur if they generate new CRLs. For instructions on how to move CRL generation to a different replicated CA, see Section 10.7.1, “Converting CA Clones and Masters”.

Master CAs also manage the relationships and information sharing between the cloned CAs by monitoring replication changes to the internal databases.

Note

If a CA which is a security domain master is cloned, then that cloned CA is also a security domain master. In that case, both the original CA and its clone share the same security domain configuration.

Important

As covered in Section 2.7.9, “Custom Configuration and Clones”, the data within the LDAP database is replicated among a master and clones, but the configuration files for the different instances are not replicated. This means that any changes which affect the CS.cfg file — such as adding a KRA connection or creating a custom profile — are not copied into a clone's configuration if the change occurs after the clone is created.

Any changes to the CA configuration should either be made to the master before any clones are created (so the custom changes are included in the cloning process) or any configuration changes must be copied over manually to the clone instances after they are created.

2.7.4. Cloning for KRAs

With KRAs, all keys archived in one KRA are replicated to the internal databases of the other KRAs. This allows a key recovery to be initiated on any clone KRA, regardless of which KRA the key was originally archived on.

After a key recovery is processed, the record of the recovery is stored in the internal database of all of the cloned KRAs.

With synchronous key recovery, although the recovery process can be initiated on any clone, it must be completed on the same single KRA on which it was initiated. This is because a recovery operation is recorded in the replicated database only after the appropriate number of approvals have been obtained from the KRA agents. Until then, the KRA on which the recovery is initiated is the only one which knows about the recovery operation.

Important

There exists a synchronous key recovery mechanism that has been deprecated in Red Hat Certificate System 9 and is not discussed in this documentation. Red Hat recommends the use of asynchronous key recovery instead.

2.7.5. Cloning for Other Subsystems

There is no real operational difference between replicated TKSs; the information created or maintained on one is replicated along the other servers.

For OCSPs, only one replicated OCSP receives CRL updates, and then the published CRLs are replicated to the clones.

2.7.6. Cloning and Key Stores

Cloning a subsystem creates two server processes performing the same functions: another new instance of the subsystem is created and configured to use the same keys and certificates to perform its operations. Depending on where the keys are stored for the master clone, the method for the clone to access the keys is very different.

If the keys and certificates are stored in the internal software token, then they must be exported from the master subsystem when it is first configured. When configuring the master instance, it is possible to backup the system keys and certificates to a PKCS #12 file by specifying the pki_backup_keys and pki_backup_password parameters in the pkispawn configuration file. See the BACKUP PARAMETERS section in the pki_default.cfg(5) man page for more details.

If the keys were not backed up during the initial configuration, you can extract them to a PKCS #12 file using the PKCS12Export utility, as described in Section 10.1, “Backing up Subsystem Keys from a Software Database”.

Then copy the PKCS #12 file over to the clone subsystem, and define its location and password in the pkispawn configuration file using the pki_clone_pkcs12_password and pki_clone_pkcs12_path parameters For more information, see the Installing a Clone section in the pkispawn(8) man page. In particular, make sure that the PKCS#12 file is accessible by the pkiuser user and that it has the correct SELinux label.

If the keys and certificates are stored on a hardware token, then the keys and certificates must be copied using hardware token specific utilities or referenced directly in the token:

Duplicate all the required keys and certificates, except the SSL/TLS server key and certificate to the clone instance. Keep the nicknames for those certificates the same. Additionally, copy all the necessary trusted root certificates from the master instance to the clone instance, such as chains or cross-pair certificates.
If the token is network-based, then the keys and certificates simply need to be available to the token; the keys and certificates do not need to be copied.
When using a network-based hardware token, make sure the high-availability feature is enabled on the hardware token to avoid single point of failure.

2.7.7. LDAP and Port Considerations

As mentioned in Section 2.7.1, “About Cloning”, part of the behavior of cloning is to replicate information between replicated subsystems, so that they work from an identical set of data and records. This means that the LDAP servers for the replicated subsystems need to be able to communicate.

If the Directory Server instances are on different hosts, then make sure that there is appropriate firewall access to allow the Directory Server instances to connect with each other.

Note

Cloned subsystems and their masters must use separate LDAP servers while they replicate data between common suffixes.

A subsystem can connect to its internal database using either SSL/TLS over an LDAPS port or over a standard connection over an LDAP port. When a subsystem is cloned, the clone instance uses the same connection method (SSL/TLS or standard) as its master to connect to the database. With cloning, there is an additional database connection though: the master Directory Server database to the clone Directory Server database. For that connection, there are three connection options:

If the master uses SSL/TLS to connect to its database, then the clone uses SSL/TLS, and the master/clone Directory Server databases use SSL/TLS connections for replication.
If the master uses a standard connection to its database, then the clone must use a standard connection, and the Directory Server databases can use unencrypted connections for replication.
If the master uses a standard connection to its database, then the clone must use a standard connection, but there is an option to use Start TLS for the master/clone Directory Server databases for replication. Start TLS opens a secure connection over a standard port.
Note
To use Start TLS, the Directory Server must still be configured to accept SSL/TLS connections. This means that prior to configuring the clone, a server certificate and a CA certificate must be installed on the Directory Server, and SSL/TLS must be enabled.

Whatever connection method (secure or standard) used by the master must be used by the clone and must be properly configured for the Directory Server databases prior to configuring the clone.

Important

Even if the clone connects to the master over a secure connection, the standard LDAP port (389 by default) must still be open and enabled on the LDAP server while cloning is configured.

For secure environments, the standard LDAP port can be disabled on the master's Directory Server instance once the clone is configured.

2.7.8. Replica ID Numbers

Cloning is based on setting up a replication agreement between the Directory Server for the master instance and the Directory Server for the cloned instance.

Servers involved together with replication are in the same replication topology. Every time a subsystem instance is cloned, it is added to the overall topology. Directory Server discerns between different servers in the topology based on their replica ID number. This replica ID must be unique among all of the servers in the topology.

As with the serial number ranges used for requests and certificates (covered in Section 2.7.3, “Cloning for CAs”), every subsystem is assigned a range of allowed replica IDs. When the subsystem is cloned, it assigns one of the replica IDs from its range to the new clone instance.

dbs.beginReplicaNumber=1
dbs.endReplicaNumber=95

The replica ID range can be refreshed with new numbers if an instance begins to exhaust its current range.

2.7.9. Custom Configuration and Clones

After a clone is created, configuration changes are not replicated between clones or between a master and a clone. The instance configuration is in the CS.cfg file — outside the replicated database.

For example, there are two CAs, a master and a clone. A new KRA is installed which is associated, at its configuration, with the master CA. The CA-KRA connector information is stored in the master CA's CS.cfg file, but this connector information is not added to the clone CA configuration. If a certificate request that includes a key archival is submitted to the master CA, then the key archival is forwarded to the KRA using the CA-KRA connector information. If the request is submitted to the clone CA, no KRA is recognized, and the key archival request is disallowed.

Changes made to the configuration of a master server or to a clone server are not replicated to other cloned instances. Any critical settings must be added manually to clones.

Note

You can set all required, custom configuration for a master server before configuring any clones. For example, install all KRAs so that all the connector information is in the master CA configuration file, create any custom profiles, or configure all publishing points for a master OCSP responder. Note that if the LDAP profiles are stored in the Directory Server, they are replicated and kept in sync across servers.

Any custom settings in the master instance will be included in the cloned instances at the time they are cloned (but not after).

Chapter 3. Supported Standards and Protocols

Red Hat Certificate System is based on many public and standard protocols and RFCs, to ensure the best possible performance and interoperability. The major standards and protocols used or supported by Certificate System 9 are outlined in this chapter, to help administrators plan their client services effectively.

3.1. TLS, ECC, and RSA

The Transport Layer Security (TLS) protocol is an universally accepted standard for authenticated and encrypted communication between clients and servers. Both client and server authentication occur over TLS.

TLS uses a combination of public-key and symmetric-key encryption. Symmetric-key encryption is much faster than public-key encryption, but public-key encryption provides better authentication techniques. An TLS session always begins with an exchange of messages called handshake, initial communication between the server and client. The handshake allows the server to authenticate itself to the client using public-key techniques, optionally allows the client to authenticate to the server, then allows the client and the server to cooperate in the creation of symmetric keys used for rapid encryption, decryption, and integrity verification during the session that follows.

TLS supports a variety of different cryptographic algorithms, or ciphers, for operations such as authenticating the server and client, transmitting certificates, and establishing session keys. Clients and servers may support different cipher suites, or sets of ciphers. Among other functions, the handshake determines how the server and client negotiate which cipher suite is used to authenticate each other, to transmit certificates, and to establish session keys.

Key-exchange algorithms like RSA and Elliptic Curve Diffie-Hellman (ECDH) govern the way the server and client determine the symmetric keys to use during an TLS session. TLS supports ECC (Elliptic Curve Cryptography) cipher suites, as well as RSA. The Certificate System supports both RSA and ECC public-key cryptographic systems natively.

In more recent practise, key-exchange algorithms are being superseded by key-agreement protocols where each of the two or more parties can influence the outcome when establishing a common key for secure communication. Key agreement is preferrable to key exchange because it allows for Perfect Forward Secrecy (PFS) to be implemented. When PFS is used, random public keys (also called temporary cipher parameters or ephemeral keys) are generated for each session by a non-deterministic algorithm for the purposes of key agreement. As a result, there is no single secret value which could lead to the compromise of multiple messages, protecting past and future communication alike.

Note

Longer RSA keys are required to provide security as computing capabilities increase. The recommended RSA key-length is 2048 bits. Though many servers continue to use 1024-bit keys, servers should migrate to at least 2048 bits. For 64-bit machines, consider using stronger keys. All CAs should use at least 2048-bit keys, and stronger keys (such as 3072 or 4096 bits) if possible.

3.1.1. Supported Cipher Suites

Cipher and hashing algorithms are in a constant flux with regard to various vulnerabilities and security strength. As a general rule, Red Hat Certificate System 9 follows the NIST guideline and supports TLS 1.1 and TLS 1.2 cipher suites pertaining to the server keys.

3.1.1.1. Recommended TLS Cipher Suites

The Transport Layer Security (TLS) protocol is a universally accepted standard for authenticated and encrypted communication between clients and servers. Red Hat Certificate System supports TLS 1.1 and 1.2.

Red Hat Certificate System supports the following cipher suites when the server is acting either as a server or as a client:

ECC

TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384

RSA

TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
TLS_DHE_RSA_WITH_AES_128_CBC_SHA
TLS_DHE_RSA_WITH_AES_256_CBC_SHA
TLS_DHE_RSA_WITH_AES_128_CBC_SHA256
TLS_DHE_RSA_WITH_AES_256_CBC_SHA256
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384

3.2. Allowed Key Algorithms and Their Sizes

Red Hat Certificate System supports the following key algorithms and sizes if they are provided by the underlying PKCS #11 module.

Allowed RSA key sizes:
- 2048 bits or greater
Allowed EC curves or equivalent as defined in the FIPS PUB 186-4 standard:
- nistp256
- nistp384
- nistp521

3.3. Allowed Hash Functions

The following keyed hash messages authentication (HMAC) are allowed:

SHA-256
SHA-384
SHA-512

The following cryptographic hashing functions are allowed:

SHA-256
SHA-384
SHA-512

3.4. IPv4 and IPv6 Addresses

Certificate System supports both IPv4 addresses and IPv6 addresses. In a very wide variety of circumstances, Certificate System subsystems or operations reference a host name or IP address; supporting both IPv4- and IPv6-style addresses ensures forward compatibility with network protocols. The operations that support IPv6 connections include the following:

Communications between subsystems, including between the TPS, TKS, and CA and for joining security domains
Token operations between the TPS and the Enterprise Security Client
Subsystem logging
Access control instructions
Operations performed with Certificate System tools, including the pki utility, the Subject Alt Name Extension tool, HttpClient, and the Bulk Issuance Tool
Client communications, including both the pkiconsole utility and IPv6-enabled browsers for web services
Certificate request names and certificate subject names, including user, server, and router certificates
Publishing
Connecting to LDAP databases for internal databases and authentication directories

Any time a host name or URL is referenced, an IP address can be used:

An IPv4 address must be in the format n.n.n.n or n.n.n.n,m.m.m.m. For example, 128.21.39.40 or 128.21.39.40,255.255.255.00.
An IPv6 address uses a 128-bit namespace, with the IPv6 address separated by colons and the netmask separated by periods. For example, 0:0:0:0:0:0:13.1.68.3, FF01::43, or 0:0:0:0:0:0:13.1.68.3,FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:255.255.255.0.

If DNS is properly configured, then an IPv4 or IPv6 address can be used to connect to the web services pages and to the subsystem Java consoles. The most common method is to use fully-qualified domain names:

https://ipv6host.example.com:8443/ca/services
pkiconsole https://ipv6host.example.com:8443/ca

To use IPv6 numeric addresses, replace the fully-qualified domain name in the URL with the IPv6 address, enclosed in brackets ([]). For example:

https://[00:00:00:00:123:456:789:00:]:8443/ca/services
pkiconsole https://[00:00:00:00:123:456:789:00:]:8443/ca

3.5. Supported PKIX Formats and Protocols

The Certificate System supports many of the protocols and formats defined in Public-Key Infrastructure (X.509) by the IETF. In addition to the PKIX standards listed here, other PKIX-listed standards are available at the IETF Datatracker website.

Table 3.1. PKIX Standards Supported in Certificate System 9
Format or Protocol	RFC or Draft	Description
X.509 version 1 and version 3		Digital certificate formats recommended by the International Telecommunications Union (ITU).
Certificate Request Message Format (CRMF)	RFC 4211	A message format to send a certificate request to a CA.
Certificate Management Message Formats (CMMF)		Message formats to send certificate requests and revocation requests from end entities to a CA and to return information to end entities. CMMF has been subsumed by another standard, CMC.
Certificate Management Messages over CS (CMC)	RFC 5274	A general interface to public-key certification products based on CS and PKCS #10, including a certificate enrollment protocol for RSA-signed certificates with Diffie-Hellman public-keys. CMC incorporates CRMF and CMMF.
Cryptographic Message Syntax (CMS)	RFC 2630	A superset of PKCS #7 syntax used for digital signatures and encryption.
PKIX Certificate and CRL Profile	RFC 5280	A standard developed by the IETF for a public-key infrastructure for the Internet. It specifies profiles for certificates and CRLs.
Online Certificate Status Protocol (OCSP)	RFC 6960	A protocol useful in determining the current status of a digital certificate without requiring CRLs.

Chapter 4. Supported Platforms

This section describes the different server platforms, hardware, tokens, and software supported by Red Hat Certificate System 9.

4.1. General Requirements

For details, see the corresponding section in the Red Hat Certificate System 9 Release Notes.

4.2. Server Support

Running the Certificate Authority (CA), Key Recovery Authority (KRA), Online Certificate Status Protocol (OCSP), Token Key Service (TKS), and Token Processing System (TPS) subsystems of Certificate System 9.7 is supported on Red Hat Enterprise Linux 7.9 and later. The supported Directory Server version is 10.6 and later.

Note

Certificate System 9.7 is supported running on a Red Hat Enterprise Linux virtual guest on a certified hypervisor. For details, see the Which hypervisors are certified to run Red Hat Enterprise Linux? solution article.

4.3. Supported Web Browsers

Certificate System 9.7 supports the following browsers:

Table 4.1. Supported Web Browsers by Platform
Platform	Agent Services	End User Pages
Red Hat Enterprise Linux	Firefox 60 and later ^[a]	Firefox 60 and later ^[a]
Windows 7	Firefox 60 and later ^[a]	Firefox 60 and later Internet Explorer 10 ^[b]
^[a] This Firefox version no longer supports the `crypto` web object used to generate and archive keys from the browser. As a result, expect limited functionality in this area. ^[b] Internet Explorer 11 is currently not supported by Red Hat Certificate System 9 because the enrollment code for this web browser depends upon Visual Basic Script, which has been deprecated in Internet Explorer 11.

Note

The only fully-supported browser for the HTML-based instance configuration is Mozilla Firefox.

4.4. Supported Hardware Security Modules

The following table lists Hardware Security Modules (HSM) supported by Red Hat Certificate System:

HSM	Firmware	Appliance Software	Client Software
nCipher nShield Connect 6000	2.61.2	CipherTools-linux64-dev-12.30.00	CipherTools-linux64-dev-12.30.00
Gemalto SafeNet Luna SA 1700 / 7000 (limited) (Limited support )	6.24.0	6.2.0-15	libcryptoki-6.2.x86_64

Chapter 5. Planning the Certificate System

Each Red Hat Certificate System subsystem can be installed on the same server machine, installed on separate servers, or have multiple instances installed across an organization. Before installing any subsystem, it is important to plan the deployment out: what kind of PKI services do you need? What are the network requirements? What people need to access the Certificate System, what are their roles, and what are their physical locations? What kinds of certificates do you want to issue and what constraints or rules need to be set for them?

This chapter covers some basic questions for planning a Certificate System deployment. Many of these decisions are interrelated; one choice impacts another, like deciding whether to use smart cards determines whether to install the TPS and TKS subsystems.

5.1. Deciding on the Required Subsystems

The Certificate System subsystems cover different aspects of managing certificates. Planning which subsystems to install is one way of defining what PKI operations the deployment needs to perform.

Certificates, like software or equipment, have a lifecycle with defined stages. At its most basic, there are three steps:

It is requested and issued.
It is valid.
It expires.

However, this simplified scenario does not cover a lot of common issues with certificates:

What if an employee leaves the company before the certificate expires?
When a CA signing certificate expires, all of the certificates issued and signed using that certificate also expire. So will the CA signing certificate be renewed, allowing its issued certificates to remain valid, or will it be reissued?
What if an employee loses a smart card or leaves it at home. Will a replacement certificate be issued using the original certificates keys? Will the other certificates be suspended or revoked? Are temporary certificates allowed?
When a certificate expires, will a new certificate be issued or will the original certificate be renewed?

This introduces three other considerations for managing certificates: revocation, renewal, and replacements.

Other considerations are the loads on the certificate authority. Are there a lot of issuance or renewal requests? Is there a lot of traffic from clients trying to validate whether certificates are valid? How are people requesting certificates supposed to authenticate their identity, and does that process slow down the issuance process?

5.1.1. Using a Single Certificate Manager

The core of the Certificate System PKI is the Certificate Manager, a certificate authority. The CA receives certificate requests and issues all certificates.

Figure 5.1. CA Only Certificate System

All of the basic processing for requests and issuing certificates can be handled by the Certificate Manager, and it is the only required subsystem. There can be a single Certificate Manager or many Certificate Managers, arranged in many different relationships, depending on the demands of the organization.

Along with issuing certificates, a Certificate Manager can also revoke certificates. One question for administrators is how to handle certificates if they are lost, compromised, or if the person or equipment for which they are issued leaves the company. Revoking a certificate invalidates it before its expiration date, and a list of revoked certificates is compiled and published by the issuing CA so that clients can verify the certificate status.

5.1.2. Planning for Lost Keys: Key Archival and Recovery

One operation the CA cannot perform, though, is key archival and recovery. A very real scenario is that a user is going to lose his private key — for instance, the keys could be deleted from a browser database or a smart card could be left at home. Many common business operations use encrypted data, like encrypted email, and losing the keys which unlock that data means the data itself is lost. Depending on the policies in the company, there probably has to be a way to recover the keys in order to regenerate or reimport a replacement certificate, and both operations require the private key.

That requires a KRA, the subsystem which specially archives and retrieves keys.

Figure 5.2. CA and KRA

The Key Recovery Authority stores encryption keys (key archival) and can retrieve those keys so that the CA can reissue a certificate (key recovery). A KRA can store keys for any certificate generated by Certificate System, whether it is done for a regular certificate or when enrolling a smart card.

The key archival and recovery process is explained in more detail in Section 2.4.5, “Archiving, Recovering, and Rotating Keys”.

Note

The KRA is intended for archival and recovery of private encryption keys only. Therefore, end users must use a browser that supports dual-key generation to store their public-private key pairs.

5.1.3. Balancing Certificate Request Processing

Another aspect of how the subsystems work together is load balancing. If a site has high traffic, then it is possible to simply install a lot of CAs, as clones of each other or in a flat hierarchy (where each CA is independent) or in a tree hierarchy (where some CAs are subordinate to other CAs); this is covered more in Section 5.2, “Defining the Certificate Authority Hierarchy”.

5.1.4. Balancing Client OCSP Requests

If a certificate is within its validity period but needs be invalidated, it can be revoked. A Certificate Manager can publish lists of revoked certificates, so that when a client needs to verify that a certificate is still valid, it can check the list. These requests are online certificate status protocol requests, meaning that they have a specific request and response format. The Certificate Manager has a built-in OCSP responder so that it can verify OCSP requests by itself.

However, as with certificate request traffic, a site may have a significant number of client requests to verify certificate status. Example Corp. has a large web store, and each customer's browser tries to verify the validity of their SSL/TLS certificates. Again, the CA can handle issuing the number of certificates, but the high request traffic affects its performance. In this case, Example Corp. uses the external OCSP Manager subsystem to verify certificate statuses, and the Certificate Manager only has to publish updated CRLs every so often.

Figure 5.3. CA and OCSP

5.1.5. Using Smart Cards

Smart cards usually require in-person enrollment and approval processes, since they use a physical medium to store key and certificate data. That means that multiple agents need to have access to the TPS and, possibly, multiple TPS subsystems in different offices or geographic locations.

The token management system is very scalable. Multiple TPSs can be configured to work with a single CA, TKS, or KRA instance, while multiple Enterprise Security Clients can communicate with a single TPS. As additional clients are installed, they can point back to the TPS instance without having to reconfigure the TPS; likewise, as TPSs are added, they can point to the same CA, TKS, and KRA instances without having to reconfigure those subsystems.

After installation, the TPS configuration can be edited to use additional CA, KRA, and TKS instances for failover support, so if the primary subsystem is unavailable, the TPS can switch to the next available system without interrupting its token services.

5.2. Defining the Certificate Authority Hierarchy

The CA is the center of the PKI, so the relationship of CA systems, both to each other (CA hierarchy) and to other subsystems (security domain) is vital to planning a Certificate System PKI.

When there are multiple CAs in a PKI, the CAs are structured in a hierarchy or chain. The CA above another CA in a chain is called an root CA; a CA below another CA in the chain is called a subordinate CA. A CA can also be subordinate to a root outside of the Certificate System deployment; for example, a CA which functions as a root CA within the Certificate System deployment can be subordinate to a third-party CA.

A Certificate Manager (or CA) is subordinate to another CA because its CA signing certificate, the certificate that allows it to issue certificates, is issued by another CA. The CA that issued the subordinate CA signing certificate controls the CA through the contents of the CA signing certificate. The CA can constrain the subordinate CA through the kinds of certificates that it can issue, the extensions that it is allowed to include in certificates, the number of levels of subordinate CAs the subordinate CA can create, and the validity period of certificates it can issue, as well as the validity period of the subordinate CAs signing certificate.

Note

Although a subordinate CA can create certificates that violate these constraints, a client authenticating a certificate that violates those constraints will not accept that certificate.

A self-signed root CA signs its own CA signing certificate and sets its own constraints as well as setting constraints on the subordinate CA signing certificates it issues.

A Certificate Manager can be configured as either a root CA or a subordinate CA. It is easiest to make the first CA installed a self-signed root, so that it is not necessary to apply to a third party and wait for the certificate to be issued. Before deploying the full PKI, however, consider whether to have a root CA, how many to have, and where both root and subordinate CAs will be located.

5.2.1. Subordination to a Public CA

Chaining the Certificate System CA to a third-party public CA introduces the restrictions that public CAs place on the kinds of certificates the subordinate CA can issue and the nature of the certificate chain. For example, a CA that chains to a third-party CA might be restricted to issuing only Secure Multipurpose Internet Mail Extensions (S/MIME) and SSL/TLS client authentication certificates, but not SSL/TLS server certificates. There are other possible restrictions with using a public CA. This may not be acceptable for some PKI deployments.

One benefit of chaining to a public CA is that the third party is responsible for submitting the root CA certificate to a web browser or other client software. This can be a major advantage for an extranet with certificates that are accessed by different companies with browsers that cannot be controlled by the administrator. Creating a root CA in the CA hierarchy means that the local organization must get the root certificate into all the browsers which will use the certificates issued by the Certificate System. There are tools to do this within an intranet, but it can be difficult to accomplish with an extranet.

5.2.2. Subordination to a Certificate System CA

The Certificate System CA can function as a root CA, meaning that the server signs its own CA signing certificate as well as other CA signing certificates, creating an organization-specific CA hierarchy. The server can alternatively be configured as a subordinate CA, meaning the server's CA signing key is signed by another CA in an existing CA hierarchy.

Setting up a Certificate System CA as the root CA means that the Certificate System administrator has control over all subordinate CAs by setting policies that control the contents of the CA signing certificates issued. A subordinate CA issues certificates by evaluating its own authentication and certificate profile configuration, without regard for the root CA's configuration.

5.2.3. Linked CA

The Certificate System Certificate Manager can function as a linked CA, chaining up to many third-party or public CAs for validation; this provides cross-company trust, so applications can verify certificate chains outside the company certificate hierarchy. A Certificate Manager is chained to a third-party CA by requesting the Certificate Manager's CA signing certificate from the third-party CA.

Related to this, the Certificate Manager also can issue cross-pair or cross-signed certificates. Cross-pair certificates create a trusted relationship between two separate CAs by issuing and storing cross-signed certificates between these two CAs. By using cross-signed certificate pairs, certificates issued outside the organization's PKI can be trusted within the system.

These are also called bridge certificates, related to the Federal Bridge Certification Authority (FBCA) definition.

5.2.4. CA Cloning

Instead of creating a hierarchy of root and subordinate CAs, it is possible to create multiple clones of a Certificate Manager and configure each clone to issue certificates within a range of serial numbers.

A cloned Certificate Manager uses the same CA signing key and certificate as another Certificate Manager, the master Certificate Manager.

Note

If there is a chance that a subsystem will be cloned, then it is easiest to export its key pairs during the configuration process and save them to a secure location. The key pairs for the original Certificate Manager have to be available when the clone instance is configured, so that the clone can generate its certificates from the original Certificate Manager's keys.

It is also possible to export the keys from the security databases at a later time, using the pk12util or the PKCS12Export commands.

Because clone CAs and original CAs use the same CA signing key and certificate to sign the certificates they issue, the issuer name in all the certificates is the same. Clone CAs and the original Certificate Managers issue certificates as if they are a single CA. These servers can be placed on different hosts for high availability failover support.

The advantage of cloning is that it distributes the Certificate Manager's load across several processes or even several physical machines. For a CA with a high enrollment demand, the distribution gained from cloning allows more certificates to be signed and issued in a given time interval.

A cloned Certificate Manager has the same features, such as agent and end-entity gateway functions, of a regular Certificate Manager.

The serial numbers for certificates issued by clones are distributed dynamically. The databases for each clone and master are replicated, so all of the certificate requests and issued certificates, both, are also replicated. This ensures that there are no serial number conflicts while serial number ranges do not have to be manually assigned to the cloned Certificate Managers.

5.3. Planning Security Domains

A security domain is a registry of PKI services. PKI services, such as CAs, register information about themselves in these domains so users of PKI services can find other services by inspecting the registry. The security domain service in Certificate System manages both the registration of PKI services for Certificate System subsystems and a set of shared trust policies.

The registry provides a complete view of all PKI services provided by the subsystems within that domain. Each Certificate System subsystem must be either a host or a member of a security domain.

A CA subsystem is the only subsystem which can host a security domain. The security domain shares the CA internal database for privileged user and group information to determine which users can update the security domain, register new PKI services, and issue certificates.

A security domain is created during CA configuration, which automatically creates an entry in the security domain CA's LDAP directory. Each entry contains all the important information about the domain. Every subsystem within the domain, including the CA registering the security domain, is recorded under the security domain container entry.

The URL to the CA uniquely identifies the security domain. The security domain is also given a friendly name, such as Example Corp Intranet PKI. All other subsystems — KRA, TPS, TKS, OCSP, and other CAs — must become members of the security domain by supplying the security domain URL when configuring the subsystem.

Each subsystem within the security domain shares the same trust policies and trusted roots which can be retrieved from different servers and browsers. The information available in the security domain is used during configuration of a new subsystem, which makes the configuration process streamlined and automated. For example, when a TPS needs to connect to a CA, it can consult the security domain to get a list of available CAs.

Each CA has its own LDAP entry. The security domain is an organizational group underneath that CA entry:

ou=Security Domain,dc=server.example.com-pki-ca

Then there is a list of each subsystem type beneath the security domain organizational group, with a special object class (pkiSecurityGroup) to identify the group type:

cn=KRAList,ou=Security Domain,o=pki-tomcat-CA
objectClass: top
objectClass: pkiSecurityGroup
cn: KRAList

Each subsystem instance is then stored as a member of that group, with a special pkiSubsystem object class to identify the entry type:

dn: cn=kra.example.com:8443,cn=KRAList,ou=Security Domain,o=pki-tomcat-CA
objectClass: top
objectClass: pkiSubsystem
cn: kra.example.com:8443
host: server.example.com
UnSecurePort: 8080
SecurePort: 8443
SecureAdminPort: 8443
SecureAgentPort: 8443
SecureEEClientAuthPort: 8443
DomainManager: false
Clone: false
SubsystemName: KRA kra.example.com 8443

If a subsystem needs to contact another subsystem to perform an operation, it contacts the CA which hosts the security domain (by invoking a servlet which connects over the administrative port of the CA). The security domain CA then retrieves the information about the subsystem from its LDAP database, and returns that information to the requesting subsystem.

The subsystem authenticates to the security domain using a subsystem certificate.

Consider the following when planning the security domain:

The CA hosting the security domain can be signed by an external authority.
Multiple security domains can be set up within an organization. However, each subsystem can belong to only one security domain.
Subsystems within a domain can be cloned. Cloning subsystem instances distributes the system load and provides failover points.
The security domain streamlines configuration between the CA and KRA; the KRA can push its KRA connector information and transport certificates automatically to the CA instead of administrators having to manually copy the certificates over to the CA.
The Certificate System security domain allows an offline CA to be set up. In this scenario, the offline root has its own security domain. All online subordinate CAs belong to a different security domain.
The security domain streamlines configuration between the CA and OCSP. The OCSP can push its information to the CA for the CA to set up OCSP publishing and also retrieve the CA certificate chain from the CA and store it in the internal database.

5.4. Determining the Requirements for Subsystem Certificates

The CA configuration determines many of the characteristics of the certificates which it issues, regardless of the actual type of certificate being issued. Constraints on the CA's own validity period, distinguished name, and allowed encryption algorithms impact the same characteristics in their issued certificates. Additionally, the Certificate Managers have predefined profiles that set rules for different kinds of certificates that they issue, and additional profiles can be added or modified. These profile configurations also impact issued certificates.

5.4.1. Determining Which Certificates to Install

When a Certificate System subsystem is first installed and configured, the certificates necessary to access and administer it are automatically created. These include an agent's certificate, server certificate, and subsystem-specific certificates. These initial certificates are shown in Table 5.1, “Initial Subsystem Certificates”.

Table 5.1. Initial Subsystem Certificates
Subsystem	Certificates
Certificate Manager	CA signing certificate OCSP signing certificate SSL/TLS server certificate Subsystem certificate User's (agent/administrator) certificate Audit log signing certificate
OCSP	OCSP signing certificate SSL/TLS server certificate Subsystem certificate User's (agent/administrator) certificate Audit log signing certificate
KRA	Transport certificate Storage certificate SSL/TLS server certificate Subsystem certificate User's (agent/administrator) certificate Audit log signing certificate
TKS	SSL/TLS server certificate User's (agent/administrator) certificate Audit log signing certificate
TPS	SSL/TLS server certificate User's (agent/administrator) certificate Audit log signing certificate

There are some cautionary considerations about replacing existing subsystem certificates.

Generating new key pairs when creating a new self-signed CA certificate for a root CA will invalidate all certificates issued under the previous CA certificate.
This means none of the certificates issued or signed by the CA using its old key will work; subordinate Certificate Managers, KRAs, OCSPs, TKSs, and TPSs will no longer function, and agents can no longer to access agent interfaces.
This same situation occurs if a subordinate CA's CA certificate is replaced by one with a new key pair; all certificates issued by that CA are invalidated and will no longer work.
Instead of creating new certificates from new key pairs, consider renewing the existing CA signing certificate.
If the CA is configured to publish to the OCSP and it has a new CA signing certificate or a new CRL signing certificate, the CA must be identified again to the OCSP.
If a new transport certificate is created for the KRA, the KRA information must be updated in the CA's configuration file, CS.cfg. The existing transport certificate must be replaced with the new one in the ca.connector.KRA.transportCert parameter.
If a CA is cloned, then when creating a new SSL/TLS server certificate for the master Certificate Manager, the clone CAs' certificate databases all need updated with the new SSL/TLS server certificate.
If the Certificate Manager is configured to publish certificates and CRLs to an LDAP directory and uses the SSL/TLS server certificate for SSL/TLS client authentication, then the new SSL/TLS server certificate must be requested with the appropriate extensions. After installing the certificate, the publishing directory must be configured to use the new server certificate.
Any number of SSL/TLS server certificates can be issued for a subsystem instance, but it really only needs one SSL/TLS certificate. This certificate can be renewed or replaced as many times as necessary.

5.4.2. Planning the CA Distinguished Name

The core elements of a CA are a signing unit and the Certificate Manager identity. The signing unit digitally signs certificates requested by end entities. A Certificate Manager must have its own distinguished name (DN), which is listed in every certificate it issues.

Like any other certificate, a CA certificate binds a DN to a public key. A DN is a series of name-value pairs that in combination uniquely identify an entity. For example, the following DN identifies a Certificate Manager for the Engineering department of a corporation named Example Corporation:

cn=demoCA, o=Example Corporation, ou=Engineering, c=US

Many combinations of name-value pairs are possible for the Certificate Manager's DN. The DN must be unique and readily identifiable, since any end entity can examine it.

5.4.3. Setting the CA Signing Certificate Validity Period

Every certificate, including a Certificate Manager signing certificate, must have a validity period. The Certificate System does not restrict the validity period that can be specified. Set as long a validity period as possible, depending on the requirements for certificate renewal, the place of the CA in the certificate hierarchy, and the requirements of any public CAs that are included in the PKI.

A Certificate Manager cannot issue a certificate that has a validity period longer than the validity period of its CA signing certificate. If a request is made for a period longer than the CA certificate's validity period, the requested validity date is ignored and the CA signing certificate validity period is used.

5.4.4. Choosing the Signing Key Type and Length

A signing key is used by a subsystem to verify and "seal" something. CAs use a CA signing certificate to sign certificates or CRLs that it issues; OCSPs use signing certificates to verify their responses to certificate status requests; all subsystems use log file signing certificates to sign their audit logs.

The signing key must be cryptographically strong to provide protection and security for its signing operations. The following signing algorithms are considered secure:

SHA256withRSA
SHA512withRSA
SHA256withEC
SHA512withEC

Note

Certificate System includes native ECC support. It is also possible to load and use a third-party PKCS #11 module with ECC-enabled. This is covered in Chapter 9, Installing an Instance with ECC System Certificates.

Along with a key type, each key has a specific bit length. Longer keys are considered cryptographically stronger than shorter keys. However, longer keys require more time for signing operations.

The default RSA key length in the configuration wizard is 2048 bits; for certificates that provide access to highly sensitive data or services, consider increasing the length to 4096 bits. ECC keys are much stronger than RSA keys, so the recommended length for ECC keys is 256 bits, which is equivalent in strength to a 2048-bit RSA key.

5.4.5. Using Certificate Extensions

An X.509 v3 certificate contains an extension field that permits any number of additional fields to be added to the certificate. Certificate extensions provide a way of adding information such as alternative subject names and usage restrictions to certificates. Older Netscape servers, such as Red Hat Directory Server and Red Hat Certificate System, require Netscape-specific extensions because they were developed before PKIX part 1 standards were defined.

The X.509 v1 certificate specification was originally designed to bind public keys to names in an X.500 directory. As certificates began to be used on the Internet and extranets and directory lookups could not always be performed, problem areas emerged that were not covered by the original specification.

Trust. The X.500 specification establishes trust by means of a strict directory hierarchy. By contrast, Internet and extranet deployments frequently involve distributed trust models that do not conform to the hierarchical X.500 approach.
Certificate use. Some organizations restrict how certificates are used. For example, some certificates may be restricted to client authentication only.
Multiple certificates. It is not uncommon for certificate users to possess multiple certificates with identical subject names but different key material. In this case, it is necessary to identify which key and certificate should be used for what purpose.
Alternate names. For some purposes, it is useful to have alternative subject names that are also bound to the public key in the certificate.
Additional attributes. Some organizations store additional information in certificates, such as when it is not possible to look up information in a directory.
Relationship with CA. When certificate chaining involves intermediate CAs, it is useful to have information about the relationships among CAs embedded in their certificates.
CRL checking. Since it is not always possible to check a certificate's revocation status against a directory or with the original certificate authority, it is useful for certificates to include information about where to check CRLs.

The X.509 v3 specification addressed these issues by altering the certificate format to include additional information within a certificate by defining a general format for certificate extensions and specifying extensions that can be included in the certificate. The extensions defined for X.509 v3 certificates enable additional attributes to be associated with users or public keys and manage the certification hierarchy. The Internet X.509 Public Key Infrastructure Certificate and CRL Profile recommends a set of extensions to use for Internet certificates and standard locations for certificate or CA information. These extensions are called standard extensions.

Note

For more information on standard extensions, see RFC 2459, RFC 3280, and RFC 3279.

The X.509 v3 standard for certificates allows organizations to define custom extensions and include them in certificates. These extensions are called private, proprietary, or custom extensions, and they carry information unique to an organization or business. Applications may not able to validate certificates that contain private critical extensions, so it not recommended that these be used in wide-spread situations.

The X.500 and X.509 specifications are controlled by the International Telecommunication Union (ITU), an international organization that primarily serves large telecommunication companies, government organizations, and other entities concerned with the international telecommunications network. The Internet Engineering Task Force (IETF), which controls many of the standards that underlie the Internet, is currently developing public-key infrastructure X.509 (PKIX) standards. These proposed standards further refine the X.509 v3 approach to extensions for use on the Internet. The recommendations for certificates and CRLs have reached proposed standard status and are in a document referred to as PKIX Part 1.

Two other standards, Abstract Syntax Notation One (ASN.1) and Distinguished Encoding Rules (DER), are used with Certificate System and certificates in general. These are specified in the CCITT Recommendations X.208 and X.209. For a quick summary of ASN.1 and DER, see A Layman's Guide to a Subset of ASN.1, BER, and DER, which is available at RSA Laboratories' web site, http://www.rsa.com.

5.4.5.1. Structure of Certificate Extensions

In RFC 3280, an X.509 certificate extension is defined as follows:

Extension  ::=  SEQUENCE  {

extnID OBJECT IDENTIFIER,
critical BOOLEAN DEFAULT FALSE,
extnValue OCTET STRING  }

The means a certificate extension consists of the following:

The object identifier (OID) for the extension. This identifier uniquely identifies the extension. It also determines the ASN.1 type of value in the value field and how the value is interpreted. When an extension appears in a certificate, the OID appears as the extension ID field (extnID) and the corresponding ASN.1 encoded structure appears as the value of the octet string (extnValue).
A flag or Boolean field called critical.
The value, which can be either true or false, assigned to this field indicates whether the extension is critical or noncritical to the certificate.
- If the extension is critical and the certificate is sent to an application that does not understand the extension based on the extension's ID, the application must reject the certificate.
- If the extension is not critical and the certificate is sent to an application that does not understand the extension based on the extension's ID, the application can ignore the extension and accept the certificate.
An octet string containing the DER encoding of the value of the extension.

Typically, the application receiving the certificate checks the extension ID to determine if it can recognize the ID. If it can, it uses the extension ID to determine the type of value used.

Some of the standard extensions defined in the X.509 v3 standard include the following:

Authority Key Identifier extension, which identifies the CA's public key, the key used to sign the certificate.
Subject Key Identifier extension, which identifies the subject's public key, the key being certified.

Note

Not all applications support certificates with version 3 extensions. Applications that do support these extensions may not be able to interpret some or all of these specific extensions.

5.4.6. Using and Customizing Certificate Profiles

Certificates have different types and different applications. They can be used to establish a single sign-on environment for a corporate network, to set up VPNs, to encrypt email, or to authenticate to a website. The requirements for all of these certificates can be different, just as there may also be different requirements for the same type of certificate for different kinds of users. These certificate characteristics are set in certificate profiles. The Certificate Manager defines a set of certificate profiles that it uses as enrollment forms when users or machines request certificates.

Certificate Profiles

A certificate profile defines everything associated with issuing a particular type of certificate, including the authentication method, the certificate content (defaults), constraints for the values of the content, and the contents of the input and output for the certificate profile. Enrollment requests are submitted to a certificate profile and are then subject to the defaults and constraints set in that certificate profile. These constraints are in place whether the request is submitted through the input form associated with the certificate profile or through other means. The certificate that is issued from a certificate profile request contains the content required by the defaults with the information required by the default parameters. The constraints provide rules for what content is allowed in the certificate.

For example, a certificate profile for user certificates defines all aspects of that certificate, including the validity period of the certificate. The default validity period can be set to two years, and a constraint can be set on the profile that the validity period for certificates requested through this certificate profile cannot exceed two years. When a user requests a certificate using the input form associated with this certificate profile, the issued certificate contains the information specified in the defaults and will be valid for two years. If the user submits a pre-formatted request for a certificate with a validity period of four years, the request is rejected since the constraints allow a maximum of two years validity period for this type of certificate.

A set of certificate profiles have been predefined for the most common certificates issued. These certificate profiles define defaults and constraints, associate the authentication method, and define the needed inputs and outputs for the certificate profile.

Modifying the Certificate Profile Parameters

The parameters of the default certificate profiles can be modified; this includes the authentication method, the defaults, the constraints used in each profile, the values assigned to any of the parameters in a profile, the input, and the output. It is also possible to create new certificate profiles for other types of certificates or for creating more than one certificate profile for a certificate type. There can be multiple certificate profiles for a particular type of certificate to issue the same type of certificate with a different authentication method or different definitions for the defaults and constraints. For example, there can be two certificate profiles for enrollment of SSL/TLS server certificates where one certificate profile issues certificates with a validity period of six months and another certificate profile issues certificates with a validity period of two years.

An input sets a text field in the enrollment form and what kind of information needs gathered from the end entity; this includes setting the text area for a certificate request to be pasted, which allows a request to be created outside the input form with any of the request information required. The input values are set as values in the certificate. The default inputs are not configurable in the Certificate System.

An output specifies how the response page to a successful enrollment is presented. It usually displays the certificate in a user-readable format. The default output shows a printable version of the resultant certificate; other outputs set the type of information generated at the end of the enrollment, such as PKCS #7.

Policy sets are sets of constraints and default extensions attached to every certificate processed through the profile. The extensions define certificate content such as validity periods and subject name requirements. A profile handles one certificate request, but a single request can contain information for multiple certificates. A PKCS#10 request contains a single public key. One CRMF request can contain multiple public keys, meaning multiple certificate requests. A profile may contain multiple sets of policies, with each set specifying how to handle one certificate request within a CRMF request.

Certificate Profile Administration

An administrator sets up a certificate profile by associating an existing authentication plug-in, or method, with the certificate profile; enabling and configuring defaults and constraints; and defining inputs and outputs. The administrator can use the existing certificate profiles, modify the existing certificate profiles, create new certificate profiles, and delete any certificate profile that will not be used in this PKI.

Once a certificate profile is set up, it appears on the Manage Certificate Profiles page of the agent services page where an agent can approve, and thus enable, a certificate profile. Once the certificate profile is enabled, it appears on the Certificate Profile tab of the end-entities page where end entities can enroll for a certificate using the certificate profile.

The certificate profile enrollment page in the end-entities interface contains links to each certificate profile that has been enabled by the agents. When an end entity selects one of those links, an enrollment page appears containing an enrollment form specific to that certificate profile. The enrollment page is dynamically generated from the inputs defined for the profile. If an authentication plug-in is configured, additional fields may be added to authenticate the user.

When an end entity submits a certificate profile request that is associated with an agent-approved (manual) enrollment, an enrollment where no authentication plug-in is configured, the certificate request is queued in the agent services interface. The agent can change some aspects of the enrollment, request, validate it, cancel it, reject it, update it, or approve it. The agent is able to update the request without submitting it or validate that the request adheres to the profile's defaults and constraints. This validation procedure is only for verification and does not result in the request being submitted. The agent is bound by the constraints set; they cannot change the request in such a way that a constraint is violated. The signed approval is immediately processed, and a certificate is issued.

When a certificate profile is associated with an authentication method, the request is approved immediately and generates a certificate automatically if the user successfully authenticates, all the information required is provided, and the request does not violate any of the constraints set up for the certificate profile. There are profile policies which allow user-supplied settings like subject names or validity periods. The certificate profile framework can also preserve user-defined content set in the original certificate request in the issued certificate.

The issued certificate contains the content defined in the defaults for this certificate profile, such as the extensions and validity period for the certificate. The content of the certificate is constrained by the constraints set for each default. Multiple policies (defaults and constraints) can be set for one profile, distinguishing each set by using the same value in the policy set ID. This is particularly useful for dealing with dual keys enrollment where encryption keys and signing keys are submitted to the same profile. The server evaluates each set with each request it receives. When a single certificate is issued, one set is evaluated, and any other sets are ignored. When dual-key pairs are issued, the first set is evaluated with the first certificate request, and the second set is evaluated with the second certificate request. There is no need for more than one set for issuing a single certificate or more than two sets for issuing dual-key pairs.

Guidelines for Customizing Certificate Profiles

Tailor the profiles for the organization to the real needs and anticipated certificate types used by the organization:

Decide which certificate profiles are needed in the PKI. There should be at least one profile for each type of certificate issued. There can be more than one certificate profile for each type of certificate to set different authentication methods or different defaults and constraints for a particular type of certificate type. Any certificate profile available in the administrative interface can be approved by an agent and then used by an end entity to enroll.
Delete any certificate profiles that will not be used.
Modify the existing certificate profiles for specific characteristics for the company's certificates.
- Change the defaults set up in the certificate profile, the values of the parameters set in the defaults, or the constraints that control the certificate content.
- Change the constraints set up by changing the value of the parameters.
- Change the authentication method.
- Change the inputs by adding or deleting inputs in the certificate profile, which control the fields on the input page.
- Add or delete the output.

5.4.6.1. Adding SAN Extensions to the SSL Server Certificate

Certificate System enables adding Subject Alternative Name (SAN) extensions to the SSL server certificate during the installation of non-root CA or other Certificate System instances. To do so, follow the instructions in the /usr/share/pki/ca/profiles/ca/caInternalAuthServerCert.cfg file and add the following parameters to the configuration file supplied to the pkispawn utility:

pki_san_inject: Set the value of this parameter to True.
pki_san_for_server_cert: Provide a list of the required SAN extensions separated by commas (,).

For example:

pki_san_inject=True
pki_san_for_server_cert=intca01.example.com,intca02.example.com,intca.example.com

5.4.7. Planning Authentication Methods

As implied in Section 5.4.6, “Using and Customizing Certificate Profiles”, authentication for the certificate process means the way that a user or entity requesting a certificate proves that they are who they say they are. There are three ways that the Certificate System can authenticate an entity:

In agent-approved enrollment, end-entity requests are sent to an agent for approval. The agent approves the certificate request.
In automatic enrollment, end-entity requests are authenticated using a plug-in, and then the certificate request is processed; an agent is not involved in the enrollment process.
In CMC enrollment, a third party application can create a request that is signed by an agent and then automatically processed.

A Certificate Manager is initially configured for agent-approved enrollment and for CMC authentication. Automated enrollment is enabled by configuring one of the authentication plug-in modules. More than one authentication method can be configured in a single instance of a subsystem. The HTML registration pages contain hidden values specifying the method used. With certificate profiles, the end-entity enrollment pages are dynamically-generated for each enabled profile. The authentication method associated with this certificate profile is specified in the dynamically-generated enrollment page.

The authentication process is simple.

An end entity submits a request for enrollment. The form used to submit the request identifies the method of authentication and enrollment. All HTML forms are dynamically-generated by the profiles, which automatically associate the appropriate authentication method with the form.
If the authentication method is an agent-approved enrollment, the request is sent to the request queue of the CA agent. If the automated notification for a request in queue is set, an email is sent to the appropriate agent that a new request has been received. The agent can modify the request as allowed for that form and the profile constraints. Once approved, the request must pass the certificate profiles set for the Certificate Manager, and then the certificate is issued. When the certificate is issued, it is stored in the internal database and can be retrieved by the end entity from the end-entities page by serial number or by request ID.
If the authentication method is automated, the end entity submits the request along with required information to authenticate the user, such as an LDAP user name and password. When the user is successfully authenticated, the request is processed without being sent to an agent's queue. If the request passes the certificate profile configuration of the Certificate Manager, the certificate is issued and stored in the internal database. It is delivered to the end entity immediately through the HTML forms.

The requirements for how a certificate request is authenticated can have a direct impact on the necessary subsystems and profile settings. For example, if an agent-approved enrollment requires that an agent meet the requester in person and verify their identity through supported documentation, the authentication process can be time-intensive, as well as constrained by the physical availability of both the agent and the requester.

5.4.8. Publishing Certificates and CRLs

A CA can publish both certificates and CRLs. Certificates can be published to a plain file or to an LDAP directory; CRLs can be published to file or an LDAP directory, as well, and can also be published to an OCSP responder to handle certificate verification.

Configuring publishing is fairly straightforward and is easily adjusted. For continuity and accessibility, though, it is good to plan out where certificates and CRLs need to be published and what clients need to be able to access them.

Publishing to an LDAP directory requires special configuration in the directory for publishing to work:

If certificates are published to the directory, than every user or server to which a certificate is issued must have a corresponding entry in the LDAP directory.
If CRLs are published to the directory, than they must be published to an entry for the CA which issued them.
For SSL/TLS, the directory service has to be configured in SSL/TLS and, optionally, be configured to allow the Certificate Manager to use certificate-based authentication.
The directory administrator should configure appropriate access control rules to control DN (entry name) and password based authentication to the LDAP directory.

5.4.9. Renewing or Reissuing CA Signing Certificates

When a CA signing certificate expires, all certificates signed with the CA's corresponding signing key become invalid. End entities use information in the CA certificate to verify the certificate's authenticity. If the CA certificate itself has expired, applications cannot chain the certificate to a trusted CA.

There are two ways of resolving CA certificate expiration:

Renewing a CA certificate involves issuing a new CA certificate with the same subject name and public and private key material as the old CA certificate, but with an extended validity period. As long as the new CA certificate is distributed to all users before the old CA certificate expires, renewing the certificate allows certificates issued under the old CA certificate to continue working for the full duration of their validity periods.
Reissuing a CA certificate involves issuing a new CA certificate with a new name, public and private key material, and validity period. This avoids some problems associated with renewing a CA certificate, but it requires more work for both administrators and users to implement. All certificates issued by the old CA, including those that have not yet expired, must be renewed by the new CA.

There are problems and advantages with either renewing or reissuing a CA certificate. Begin planning the CA certificate renewal or re-issuance before installing any Certificate Managers, and consider the ramifications the planned procedures may have for extensions, policies, and other aspects of the PKI deployment.

Note

Correct use of extensions, for example the authorityKeyIdentifier extension, can affect the transition from an old CA certificate to a new one.

5.5. Planning for Network and Physical Security

When deploying any Certificate System subsystem, the physical and network security of the subsystem instance has to be considered because of the sensitivity of the data generated and stored by the subsystems.

5.5.1. Considering Firewalls

There are two considerations about using firewalls with Certificate System subsystems:

Protecting sensitive subsystems from unauthorized access
Allowing appropriate access to other subsystems and clients outside of the firewall

The CA, KRA, and TKS are always placed inside a firewall because they contain critical information that can cause devastating security consequences if they are compromised.

The TPS and OCSP can be placed outside the firewall. Likewise, other services and clients used by the Certificate System can be on a different machine outside the firewall. In that case, the local networks have to be configured to allow access between the subsystems behind the firewall and the services outside it.

The LDAP database can be on a different server, even on a different network, than the subsystem which uses it. In this case, all LDAP ports (389 for LDAP and 636 for LDAPS, by default) need to be open in the firewall to allow traffic to the directory service. Without access to the LDAP database, all subsystem operations can fail.

As part of configuring the firewalls, if iptables is enabled, then it must have configured policies to allow communication over the appropriate Certificate System ports. Configuring iptables is described in the Red Hat Security Guide.

5.5.2. Considering Physical Security and Location

Because of the sensitive data they hold, consider keeping the CA, KRA, and TKS in a secure facility with adequate physical access restrictions. Just as network access to the systems needs to be restricted, the physical access also needs to be restricted.

Along with finding a secure location, consider the proximity to the subsystem agents and administrators. Key recovery, for example, can require multiple agents to give approval; if these agents are spread out over a large geographical area, then the time differences may negatively impact the ability to retrieve keys. Plan the physical locations of the subsystems, then according to the locations of the agents and administrators who will manage the subsystem.

5.5.3. Planning Ports

Each Certificate System server uses up to four ports:

A non-secure HTTP port for end entity services that do not require authentication
A secure HTTP port for end entity services, agent services, administrative console, and admin services that require authentication
A Tomcat Server Management port
A Tomcat AJP Connector Port

All of the service pages and interfaces described in the Red Hat Certificate System User Interfaces chapter in the Red Hat Certificate System Administration Guide are connected to using the instance's URL and the corresponding port number. For example:

https://server.example.com:8443/ca/ee/ca

To access the admin console, the URL specifies the admin port:

pkiconsole https://server.example.com:8443/ca

All agent and admin functions require SSL/TLS client authentication. For requests from end entities, the Certificate System listens on both the SSL/TLS (encrypted) port and non-SSL/TLS ports.

The ports are defined in the server.xml file. If a port is not used, it can be disabled in that file. For example:

<Service name="Catalina">
    <!--Connector port="8080" ... /-->  unused standard port   
    <Connector port="8443" ... />

Whenever a new instance in installed, make sure that the new ports are unique on the host system.

To verify that a port is available for use, check the appropriate file for the operating system. Port numbers for network-accessible services are usually maintained in a file named services. On Red Hat Enterprise Linux, it is also helpful to confirm that a port is not assigned by SELinux, by running the command semanage port -l to list all ports which currently have an SELinux context.

When a new subsystem instance is created, any number between 1 and 65535 can be specified as the secure port number.

5.6. Tokens for Storing Certificate System Subsystem Keys and Certificates

A token is a hardware or software device that performs cryptographic functions and stores public-key certificates, cryptographic keys, and other data. The Certificate System defines two types of tokens, internal and external, for storing key pairs and certificates that belong to the Certificate System subsystems.

An internal (software) token is a pair of files, usually called the certificate database (cert8.db) and key database (key3.db), that the Certificate System uses to generate and store its key pairs and certificates. The Certificate System automatically generates these files in the filesystem of its host machine when first using the internal token. These files are created during the Certificate System subsystem configuration if the internal token was selected for key-pair generation.

These security databases are located in the /var/lib/pki/instance_name/alias directory.

An external token refers to an external hardware device, such as a smart card or hardware security module (HSM), that the Certificate System uses to generate and store its key pairs and certificates. The Certificate System supports any hardware tokens that are compliant with PKCS #11.

PKCS #11 is a standard set of APIs and shared libraries which isolate an application from the details of the cryptographic device. This enables the application to provide a unified interface for PKCS #11-compliant cryptographic devices.

The PKCS #11 module implemented in the Certificate System supports cryptographic devices supplied by many different manufacturers. This module allows the Certificate System to plug in shared libraries supplied by manufacturers of external encryption devices and use them for generating and storing keys and certificates for the Certificate System managers.

Consider using external tokens for generating and storing the key pairs and certificates used by Certificate System. These devices are another security measure to safeguard private keys because hardware tokens are sometimes considered more secure than software tokens.

Before using external tokens, plan how the external token is going to be used with the subsystem:

All system keys for a subsystem must be generated on the same token.
The subsystem must be installed in an empty HSM slot. If the HSM slot has previously been used to store other keys, then use the HSM vendor's utilities to delete the contents of the slot. The Certificate System has to be able to create certificates and keys on the slot with default nicknames. If not properly cleaned up, the names of these objects may collide with previous instances.

The Certificate System can also use hardware cryptographic accelerators with external tokens. Many of the accelerators provide the following security features:

Fast SSL/TLS connections. Speed is important to accommodate a high number of simultaneous enrollment or service requests.
Hardware protection of private keys. These devices behave like smart cards by not allowing private keys to be copied or removed from the hardware token. This is important as a precaution against key theft from an active attack of an online Certificate Manager.

The Certificate System supports the nCipher nShield hardware security module (HSM), by default. Certificate System-supported HSMs are automatically added to the secmod.db database with modutil during the pre-configuration stage of the installation, if the PKCS #11 library modules are in the default installation paths.

During configuration, the Security Modules panel displays the supported modules, along with the NSS internal software PKCS #11 module. All supported modules that are detected show a status of Found and is individually marked as either Logged in or Not logged in. If a token is found but not logged in, it is possible to log in using the Login under Operations. If the administrator can log into a token successfully, the password is stored in a configuration file. At the next start or restart of the Certificate System instance, the passwords in the password store are used to attempt a login for each corresponding token.

Administrators are allowed to select any of the tokens that are logged in as the default token, which is used to generate system keys.

5.7. A Checklist for Planning the PKI

Q: How many security domains will be created, and what subsystem instances will be placed in each domain?
Q: What ports should be assigned for each subsystem? Is it necessary to have a single SSL/TLS port, or is it better to have port separation for extra security?
Q: What subsystems should be placed behind firewalls? What clients or other subsystems need to access those firewall-protected subsystems and how will access be granted? Is firewall access allowed for the LDAP database?
Q: What subsystems need to be physically secured? How will access be granted, and who will be granted access?
Q: What is the physical location of all agents and administrators? What is the physical location of the subsystems? How will administrators or agents access the subsystem services in a timely-manner? Is it necessary to have subsystems in each geographical location or time zone?
Q: How many subsystems do you need to install?
Q: Will any subsystems need to be cloned and, if so, what are the methods for securely storing their key materials?
Q: Will the subsystem certificates and keys be stored on the internal software token in Certificate System or on an external hardware token?
Q: What are the requirements for the CA signing certificate? Does the Certificate System need control over attributes like the validity period? How will the CA certificates be distributed?
Q: What kinds of certificates will be issued? What characteristics do they need to have, and what profile settings are available for those characteristics? What restrictions need to be placed on the certificates?
Q: What are the requirements for approving a certificate request? How does the requester authenticate himself, and what kind of process is required to approve the request?
Q: Will many external clients need to validate certificate status? Can the internal OCSP in the Certificate Manager handle the load?
Q: Will the PKI allow replacement keys? Will it require key archival and recovery?
Q: Will the organization use smart cards? If so, will temporary smart cards be allowed if smart cards are mislaid, requiring key archival and recovery?
Q: Where will certificates and CRLs be published? What configuration needs to be done on the receiving end for publishing to work? What kinds of certificates or CRLs need to be published and how frequently?

How many security domains will be created, and what subsystem instances will be placed in each domain?

A subsystem can only communicate with another subsystem if they have a trusted relationship. Because the subsystems within a security domain have automatic trusted relationships with each other, it is important what domain a subsystem joins. Security domains can have different certificate issuing policies, different kinds of subsystems within them, or a different Directory Server database. Map out where (both on the physical machine and in relation to each other) each subsystem belongs, and assign it to the security domain accordingly.

What ports should be assigned for each subsystem? Is it necessary to have a single SSL/TLS port, or is it better to have port separation for extra security?

The most secure solution is to use separate ports for each SSL/TLS interface. However, the feasibility of implementing multiple ports may depends on your network setup, firewall rules, and other network conditions.

What subsystems should be placed behind firewalls? What clients or other subsystems need to access those firewall-protected subsystems and how will access be granted? Is firewall access allowed for the LDAP database?

The location to install a subsystem depends on the network design. The OCSP subsystem is specifically designed to operate outside a firewall for user convenience, while the CA, KRA, and TPS should all be secured behind a firewall for increased security.

When deciding the location of the subsystems, it is critical to plan what other subsystems or services that server needs to access (including the internal database, a CA, or external users) and look at firewall, subnet, and VPN configuration.

What subsystems need to be physically secured? How will access be granted, and who will be granted access?

The CA, TKS, and KRA all store extremely sensitive key and certificate information. For some deployments, it may be necessary to limit physical access to the machines these subsystems run on. In that case, both the subsystems and their host machines must be included in the larger infrastructure inventory and security design.

What is the physical location of all agents and administrators? What is the physical location of the subsystems? How will administrators or agents access the subsystem services in a timely-manner? Is it necessary to have subsystems in each geographical location or time zone?

The physical location of Certificate System users may impact things like request approval and token enrollment, as well as system performance because of network lag time. The importance of response time for processing certificate operations should be taken into account when deciding where and how many subsystems to install.

How many subsystems do you need to install?

The primary consideration is the expected load for each subsystem and then, secondarily, geographical or departmental divisions. Subsystems with fairly low loads (like the KRA or TKS) may only require a single instance for the entire PKI. Systems with high load (the CA) or which may benefit from local instances for local agents (like the TPS) may require multiple instances.

Subsystems can be cloned, meaning they essentially are clustered, operating as a single unit, which is good for load balancing and high availability. Cloning is especially good for CAs and KRAs, where the same key and certificate data may need to be accessed by larger numbers of users or to have reliable failover.

When planning for multiple subsystem instances, keep in mind how the subsystems fit within the established security domains. Security domains create trusted relationships between subsystems, allowing them to work together to find available subsystems to respond to immediate needs. Multiple security domains can be used in a single PKI, with multiple instances of any kind of subsystem, or a single security domain can be used for all subsystems.

Will any subsystems need to be cloned and, if so, what are the methods for securely storing their key materials?

Cloned subsystems work together, essentially as a single instance. This can be good for high demand systems, failover, or load balancing, but it can become difficult to maintain. For example, cloned CAs have serial number ranges for the certificates they issue, and a clone could hit the end of its range.

Will the subsystem certificates and keys be stored on the internal software token in Certificate System or on an external hardware token?

Certificate System supports two hardware security modules (HSM): nCipher nShield and Safenet LunaSA. Using a hardware token can require additional setup and configuration before installing the subsystems, but it also adds another layer of security.

What are the requirements for the CA signing certificate? Does the Certificate System need control over attributes like the validity period? How will the CA certificates be distributed?

The real question here is, will the CA bee a root CA which sets its own rules on issuing certificates or will it be a subordinate CA where another CA (another CA in your PKI or even an external CA) sets restrictions on what kind of certificates it can issue.

A Certificate Manager can be configured as either a root CA or a subordinate CA. The difference between a root CA and a subordinate CA is who signs the CA signing certificate. A root CA signs its own certificate. A subordinate CA has another CA (either internal or external) sign its certificate.

A self-signing root CA issues and signs its own CA signing certificate. This allows the CA to set its own configuration rules, like validity periods and the number of allowed subordinate CAs.

A subordinate CA has its certificates issued by a public CA or another Certificate System root CA. This CA is subordinate to the other CA's rules about its certificate settings and how the certificate can be used, such as the kinds of certificates that it can issue, the extensions that it is allowed to include in certificates, and the levels of subordinate CAs the subordinate CA can create.

One option is to have the Certificate manager subordinate to a public CA. This can be very restrictive, since it introduces the restrictions that public CAs place on the kinds of certificates the subordinate CA can issue and the nature of the certificate chain. On the other hand, one benefit of chaining to a public CA is that the third party is responsible for submitting the root CA certificate to a web browser or other client software, which is a major advantage for certificates that are accessed by different companies with browsers that cannot be controlled by the administrator.

The other option is make the CA subordinate to a Certificate System CA. Setting up a Certificate System CA as the root CA means that the Certificate System administrator has control over all subordinate CAs by setting policies that control the contents of the CA signing certificates issued.

It is easiest to make the first CA installed a self-signed root, so that it is not necessary to apply to a third party and wait for the certificate to be issued. Make sure that you determine how many root CAs to have and where both root and subordinate CAs will be located.

What kinds of certificates will be issued? What characteristics do they need to have, and what profile settings are available for those characteristics? What restrictions need to be placed on the certificates?

As touched on in Section 5.4.6, “Using and Customizing Certificate Profiles”, the profiles (the forms which configure each type of certificate issued by a CA) can be customized. This means that the subject DN, the validity period, the type of SSL/TLS client, and other elements can be defined by an administrator for a specific purpose. For security, profiles should provide only the functionality that is required by the PKI. Any unnecessary profiles should be disabled.

What are the requirements for approving a certificate request? How does the requester authenticate himself, and what kind of process is required to approve the request?

The request approval process directly impacts the security of the certificate. Automated processes are much faster but are less secure since the identity of the requester is only superficially verified. Likewise, agent-approved enrollments are more secure (since, in the most secure scenario they can require an in-person verification and supporting identification) but they can also be the most time-consuming.

First determine how secure the identity verification process needs to be, then determine what authentication (approval) mechanism is required to validate that identity.

Will many external clients need to validate certificate status? Can the internal OCSP in the Certificate Manager handle the load?

Publishing CRLs and validating certificates is critical. Determine what kinds of clients will be checking the certificate status (will it mainly be internal clients? external clients? will they be validating user certificates or server certificates?) and also try to determine how many OCSP checks will be run. The CA has an internal OCSP which can be used for internal checks or infrequent checks, but a large number of OCSP checks could slow down the CA performance. For a larger number of OCSP checks and especially for large CRLs, consider using a separate OCSP Manager to take the load off the CA.

Will the PKI allow replacement keys? Will it require key archival and recovery?

If lost certificates or tokens are simply revoked and replaced, then there does not need to be a mechanism to recover them. However, when certificates are used to sign or encrypt data such as emails, files, or harddrives, then the key must always be available so that the data can be recovered. In that case, use a KRA to archive the keys so the data can always be accessed.

Will the organization use smart cards? If so, will temporary smart cards be allowed if smart cards are mislaid, requiring key archival and recovery?

If no smart cards are used, then it is never necessary to configure the TPS or TKS, since those subsystems are only used for token management. However, if smart cards are used, then the TPS and TKS are required. If tokens can be lost and replaced, then it is also necessary to have a KRA to archive the keys so that the token's certificates can be regenerated.

Where will certificates and CRLs be published? What configuration needs to be done on the receiving end for publishing to work? What kinds of certificates or CRLs need to be published and how frequently?

The important thing to determine is what clients need to be able to access the certificate or CRL information and how that access is allowed. From there, you cna define the publishing policy.

5.8. Optional Third-party Services

5.8.1. Load Balancers

5.8.2. Backup Hardware and Software

Part II. Installing Red Hat Certificate System

This section describes the requirements and procedures for installing Red Hat Certificate System.

Chapter 6. Prerequisites and Preparation for Installation

The Red Hat Certificate System installation process requires some preparation of the environment. This chapter describes the requirements, dependencies, and other prerequisites when installing Certificate System subsystems.

6.1. Installing Red Hat Enterprise Linux

Red Hat Certificate System requires the latest version of Red Hat Enterprise Linux 7. For details about installing Red Hat Enterprise Linux, see the Red Hat Enterprise Linux Installation Guide.

To enable the Federal Information Processing Standard (FIPS) on Red Hat Enterprise Linux, see the Red Hat Security Guide.

Important

FIPS mode must be enabled before you install Certificate System. To ensure FIPS mode is enabled:

# sysctl crypto.fips_enabled

If the returned value is 1, FIPS mode is enabled.

6.2. Securing the System Using SELinux

Security-Enhanced Linux (SELinux) is an implementation of a mandatory access control mechanism in the Linux kernel, checking for allowed operations after standard discretionary access controls are checked. SELinux can enforce rules on files and processes in a Linux system, and on their actions, based on defined policies.

In most cases, no actions are required to run Certificate System with SELinux in enforcing mode. If a procedure in the Certificate System documentation requires to manually set SELinux-related settings, such as when using a Hardware Security Module (HSM), it is mentioned in the corresponding section.

For further details about SELinux, see the SELinux User's and Administrator's Guide.

6.2.1. Verifying if SELinux is Running in Enforcing Mode

By default, after installing Red Hat Enterprise Linux, SELinux is enabled and running in enforcing mode and no further actions are required.

To display the current SELinux mode, enter:

# getenforce

6.3. Firewall Configuration

The following table lists the default ports used by Certificate System subsystems:

Table 6.1. Certificate System Default Ports
Service	Port	Protocol
HTTP	8080	TCP
HTTPS	8443	TCP
Tomcat Management	8005	TCP

When you set up Certificate System using the pkispawn utility, you can customize the port numbers. If you use different ports than the defaults listed above, open them correspondingly in the firewall as described in Section 6.3.1, “Opening the Required Ports in the Firewall”. For further details about ports, see Section 5.5.3, “Planning Ports”.

For ports required to access Directory Server, see corresponding section in Opening required ports in the firewall.

6.3.1. Opening the Required Ports in the Firewall

To enable communication between the clients and Certificate System, open the required ports in your firewall:

Make sure the firewalld service is running.
```
# systemctl status firewalld
```
To start firewalld and configure it to start automatically when the system boots:
```
# systemctl start firewalld
# systemctl enable firewalld
```
Open the required ports using the firewall-cmd utility. For example, to open the Certificate System default ports in the default firewall zone:
```
# firewall-cmd --permanent --add-port={8080/tcp,8443/tcp,8009/tcp,8005/tcp}
```
For details on using firewall-cmd to open ports on a system, see the Red Hat Enterprise Linux Security Guide or the firewall-cmd(1) man page.
Reload the firewall configuration to ensure that the change takes place immediately:
```
# firewall-cmd --reload
```

6.4. Hardware Security Module

To use a Hardware Security Module (HSM), a Federal Information Processing Standard (FIPS) 140-2 validated HSM is required. See your HSM documentation for installing, configuring, and how to set up the HSM in FIPS mode.

6.4.1. Setting up SELinux for an HSM

Certain HSMs require that you manually update SELinux settings before you can install Certificate System.

The following section describes the required actions for supported HSMs:

nCipher nShield

After you installed the HSM and before you start installing Certificate System:

Reset the context of files in the /opt/nfast/ directory:
```
# restorecon -R /opt/nfast/
```

Restart the nfast software.

# /opt/nfast/sbin/init.d-ncipher restart

Gemalto Safenet LunaSA HSM

No SELinux-related actions are required before you start installing Certificate System.

For details about the supported HSMs, see Section 4.4, “Supported Hardware Security Modules”.

6.4.2. Enabling FIPS Mode on an HSM

To enable FIPS Mode on HSMs, please refer to your HSM vendor's documentation for specific instructions.

Important

nCipher HSM: On a nCipher HSM, the FIPS mode can only be enabled when generating the Security World, this cannot be changed afterwards. While there is a variety of ways to generate the Security World, the preferred method is always to use the new-world command. For guidance on how to generate a FIPS-compliant Security World, please follow the nCipher HSM vendor's documentation.
LunaSA HSM: Similarly, enabling the FIPS mode on a Luna HSM must be done during the initial configuration, since changing this policy zeroizes the HSM as a security measure. For details, please refer to the Luna HSM vendor's documentation.

6.4.3. Verifying if FIPS Mode is Enabled on an HSM

This section describes how to verify if FIPS mode is enabled for certain HSMs. For other HSMs, see the hardware manufacturer's documentation.

6.4.3.1. Verifying if FIPS Mode is Enabled on an nCipher HSM

Note

Please refer to your HSM vendor’s documentation for the complete procedure.

To verify if the FIPS mode is enabled on an nCipher HSM, enter:

# /opt/nfast/bin/nfkminfo

With older versions of the software, if the StrictFIPS140 is listed in the state flag, the FIPS mode is enabled. In newer vesions, it is however better to check the new mode line and look for fips1402level3. In all cases, there should also be an hkfips key present in the nfkminfo output.

6.4.3.2. Verifying if FIPS Mode is Enabled on a Luna SA HSM

Note

Please refer to your HSM vendor’s documentation for the complete procedure.

To verify if the FIPS mode is enabled on a Luna SA HSM:

Open the lunash management console

Use the hsm show command and verify that the output contains the text The HSM is in FIPS 140-2 approved operation mode.:

lunash:> hsm show
...
       FIPS 140-2 Operation:
       =====================
       The HSM is in FIPS 140-2 approved operation mode.
...

6.4.4. Preparing for Installing Certificate System with an HSM

In Section 7.3, “Understanding the pkispawn Utility”, you are instructed to use the following parameters in the configuration file you pass to the pkispawn utility when installing Certificate System with an HSM:

...
[DEFAULT]
##########################
# Provide HSM parameters #
##########################
pki_hsm_enable=True
pki_hsm_libfile=hsm_libfile
pki_hsm_modulename=hsm_modulename
pki_token_name=hsm_token_name
pki_token_password=pki_token_password

########################################
# Provide PKI-specific HSM token names #
########################################
pki_audit_signing_token=hsm_token_name
pki_ssl_server_token=hsm_token_name
pki_subsystem_token=hsm_token_name
...

The values of the pki_hsm_libfile and pki_token_name parameter depend on your specific HSM installation. These values allow the pkispawn utility to set up your HSM and enable Certificate System to connect to it.
The value of the pki_token_password depends upon your particular HSM token's password. The password gives the pkispawn utility read and write permissions to create new keys on the HSM.
The value of the pki_hsm_modulename is a name used in later pkispawn operations to identify the HSM. The string is an identifier you can set as whatever you like. It allows pkispawn and Certificate System to refer to the HSM and configuration information by name in later operations.

The following section provides settings for individual HSMs. If your HSM is not listed, consult your HSM manufacturer's documentation.

6.4.4.1. nCipher HSM Parameters

For a nCipher HSM, such as a nCipher nShield Connect 6000, set the following parameters:

pki_hsm_libfile=/opt/nfast/toolkits/pkcs11/libcknfast.so
pki_hsm_modulename=nfast

Note that you can set the value of pki_hsm_modulename to any value. The above is a suggested value.

Example 6.1. Identifying the Token Name

To identify the token name, run the following command as the root user:

[root@example911 ~]# /opt/nfast/bin/nfkminfo
World
 generation  2

...~snip~...

Cardset
 name          "NHSM6000-OCS"
 k-out-of-n    1/4
 flags         NotPersistent PINRecoveryRequired(enabled) !RemoteEnabled
 timeout       none

...~snip~...

The value of the name field in the Cardset section lists the token name.

Set the token name as follows:

pki_token_name=NHSM6000-OCS

6.4.4.2. SafeNet / Luna SA HSM Parameters

For a SafeNet / Luna SA HSM, such as a SafeNet Luna Network HSM, specify the following parameters:

pki_hsm_libfile=/usr/safenet/lunaclient/lib/libCryptoki2_64.so
pki_hsm_modulename=lunasa

Note that you can set the value of pki_hsm_modulename to any value. The above is a suggested value.

Example 6.2. Identifying the Token Name

To identify the token name, run the following command as the root user:

# /usr/safenet/lunaclient/bin/vtl verify

The following Luna SA Slots/Partitions were found:

Slot    Serial #            Label
====    ================    =====
   0       1209461834772     lunasaQE

The value in the label column lists the token name.

Set the token name as follows:

pki_token_name=lunasaQE

6.4.5. Backing up Keys on Hardware Security Modules

It is not possible to export keys and certificates stored on an HSM to a .p12 file. If such an instance is to be backed-up, contact the manufacturer of your HSM for support.

6.5. Installing Red Hat Directory Server

Certificate System uses Red Hat Directory Server to store system certificates and user data. You can install both Directory Server and Certificate System on the same or any other host in the network.

6.5.1. Preparing a Directory Server Instance for Certificate System

Perform the following steps to install Red Hat Directory Server:

Make sure you have attached a subscription that provides Directory Server to the host.

Enable the Directory Server repository:

# subscription-manager repos --enable=dirsrv-10-for-rhel-7-x86_64-rpms

Install the Directory Server and openldap-clients packages:

# dnf module install redhat-ds

# dnf install openldap-clients

Set up a Directory Server instance.

Generate a DS configuration file; for example, /tmp/ds-setup.inf:
```
$ dscreate create-template /tmp/ds-setup.inf
```

Customize the DS configuration file as follows:

$ sed -i \
            -e "s/;instance_name = .*/instance_name = localhost/g" \
            -e "s/;root_password = .*/root_password = Secret.123/g" \
            -e "s/;suffix = .*/suffix = dc=example,dc=com/g" \
            -e "s/;create_suffix_entry = .*/create_suffix_entry = True/g" \
            -e "s/;self_sign_cert = .*/self_sign_cert = False/g" \
            /tmp/ds-setup.inf

Create the instance using the dscreate command with the setup configuration file:
```
# dscreate from-file /tmp/ds-setup.inf
```

For a detailed procedure, see the Red Hat Directory Server Installation Guide.

6.5.2. Preparing for Configuring Certificate System

In Section 7.3, “Understanding the pkispawn Utility”, if you chose to set up TLS between Certificate System and Directory Server, use the following parameters in the configuration file you pass to the pkispawn utility when installing Certificate System:

Note

We need to first create a basic TLS server authentication connection. At the end, during post-installation, we will return and make the connection require a client authentication certificate to be presented to Directory Server. At that time, once client authentication is set up, the pki_ds_password would no longer be relevant.

pki_ds_database=back_end_database_name
pki_ds_hostname=host_name
pki_ds_secure_connection=True
pki_ds_secure_connection_ca_pem_file=path_to_CA_or_self-signed_certificate
pki_ds_password=password
pki_ds_ldaps_port=port
pki_ds_bind_dn=cn=Directory Manager

The value of the pki_ds_database parameter is a name used by the pkispawn utility to create the corresponding subsystem database on the Directory Server instance.

The value of the pki_ds_hostname parameter depends on the install location of the Directory Server instance. This depends on the values used in Section 6.5.1, “Preparing a Directory Server Instance for Certificate System”.

When you set pki_ds_secure_connection=True, the following parameters must be set:

pki_ds_secure_connection_ca_pem_file: Sets the fully-qualified path including the file name of the file which contains an exported copy of the Directory Server's CA certificate. This file must exist prior to pkispawn being able to utilize it.
pki_ds_ldaps_port: Sets the value of the secure LDAPS port Directory Server is listening to. The default is 636.

6.5.3. Replacing the Temporary Certificate

Note

This section requires a root CA installed and running. You will be instructed to follow instruction in this section during post-installation.

This section describes the process to replace the temporary self-signed Directory Server certificate with a permanent Directory Server certificate issued by the newly-installed CA, or to replace an old Directory Server certificate with a new one.

Obtain a new Directory Server server certificate. Submit the request for the new certificate signed by the CA. To get a new Directory Server certificate using the CMC method, see the Obtaining System and Server Certificates section in the Red Hat Certificate System Administration Guide.
In the above section, follow the guidance to create a TLS server certificate. Once the certificate is created, it must be imported back into the Directory Server's certificate database.
Stop the Directory Server instance before accessing the NSS database:
```
# systemctl stop dirsrv@instance_name
```

Delete the old Directory Server certificate:

# certutil -F -d /etc/dirsrv/slapd-instance_name -f /etc/dirsrv/slapd-instance_name/password.txt -n "DS Certificate"

Import the CA certificate downloaded earlier:

# PKICertImport -d /etc/dirsrv/slapd-instance_name -f /etc/dirsrv/slapd-instance_name/password.txt -n "CA Certificate" -t "CT,C,C" -a -i ca.crt -u L

Import the new Directory Server certificate downloaded earlier:

# PKICertImport -d /etc/dirsrv/slapd-instance_name -f /etc/dirsrv/slapd-instance_name/password.txt -n "DS Certificate" -t ",," -a -i ds.crt -u V

Start the Directory Server instance:
```
# systemctl start dirsrv@instance_name
```

Remove the old Directory Server Certificate from PKI CA:

Stop the Certificate System instance:

# systemctl stop pki-tomcatd@instance_name.service

Remove the certificate:

# certutil -D -d /var/lib/pki/instance_name/alias/ -n "DS Certificate"

Start the Certificate System instance:

# systemctl start pki-tomcatd@instance_name.service

Verify that the new Directory Server certificate is signed by the CA installed in the NSS database:
1. Display the Directory Server certificate
```
$ certutil -L -d /etc/dirsrv/slapd-instance_name -n "DS Certificate"

Issuer: "CN=CA Signing Certificate,O=EXAMPLE"
Subject: "CN=server.example.com"
```
2. Verify the old Directory Server certificate no longer exists in the PKI NSS database:
```
$ certutil -L -d /var/lib/pki/instance_name/alias
```
3. Verify Certificate System can connect to Directory Server using the new certificate:
```
$ pki cert-find
```

6.5.4. Enabling TLS Client Authentication

Note

This section requires a root CA installed and running. If you used a temporary LDAP server certificate, replace it first by following Section 6.5.3, “Replacing the Temporary Certificate”. Follow instruction in this section during post-installation.

If you choose to enable TLS client authentication, once the basic TLS server authentication has been configured and running when installing the CS subsystem, we can now double back and attempt to enable client authentication from a given subsystem to the LDAP server.

There are two parts to setting up client authentication. The first part is configuring the LDAP directory to require TLS mutual authentication. This procedure is detailed in 9.8. Using Certificate-based Client Authentication in Red Hat Directory Server Administration Guide.

Note the following:

pkispawn already automatically created a pkidbuser on its internal directory server, where the CS instance's "subsystem certificate" (for example subsystemCert cert-pki-ca) that is used for outbound TLS client authentication is stored in the user entry. Therefore, there is no need to create another LDAP user or another certificate for the TLS client-authentication.

When creating content for /etc/dirsrv/slapd-instance_name/certmap.conf, use the following format:

certmap rhcs <certificate issuer DN>
rhcs:CmapLdapAttr seeAlso
rhcs:verifyCert on

For example

certmap rhcs CN=CA Signing Certificate,OU=pki-tomcat-ca,O=pki-tomcat-ca-SD
rhcs:CmapLdapAttr seeAlso
rhcs:verifyCert on

After configuring, restart the Directory Server.

The second part is adding configuration to the Red Hat Certificate System instance so that it knows which port and certificate is to be used to communicate with its internal LDAP server using TLS mutual authentication. This involves editing the RHCS instance's CS.cfg file located at <instance directory>/<subsystem type>/conf/CS.cfg. For example /var/lib/pki/instance_name/ca/conf/CS.cfg

In the CS.cfg, please add the RHCS instance's subsystem certificate nickname to internaldb.ldapauth.clientCertNickname, and remove the two unused entries:

internaldb.ldapauth.bindDN
internaldb.ldapauth.bindPWPrompt

As shown below:

internaldb._000=##
internaldb._001=## Internal Database
internaldb._002=##
internaldb.basedn=o=pki-tomcat-ca-SD
internaldb.database=pki-tomcat-ca
internaldb.maxConns=15
internaldb.minConns=3
internaldb.ldapauth.authtype=SslClientAuth
internaldb.ldapauth.clientCertNickname=HSM-A:subsystemCert pki-tomcat-ca
internaldb.ldapconn.host=example.com
internaldb.ldapconn.port=11636
internaldb.ldapconn.secureConn=true

Restart the CS instance at the end of the Post-installation step.

Note

The internaldb.basedn and internaldb.database parameters must be configured to match your specific LDAP instance.

For compliance, internaldb.ldapauth.authtype=SslClientAuth and internaldb.ldapconn.secureConn=true must be set, and the value of the internaldb.ldapauth.clientCertNickname must match the nickname of the TLS client certificate to authenticate against LDAP with in the NSS DB.

All other values can be changed as desired to reflect your environment or availability needs.

6.6. Attaching a Red Hat Subscription and Enabling the Certificate System Package Repository

Before you can install and update Certificate System using the yum utility, you must enable the corresponding repository:

Attach the Red Hat subscriptions to the system:

Skip this step, if your system is already registered or has a Certificate Server subscription attached.

# subscription-manager register --auto-attach
Username: admin@example.com
Password:
The system has been registered with id: 566629db-a4ec-43e1-aa02-9cbaa6177c3f

Installed Product Current Status:
Product Name:           Red Hat Enterprise Linux Server
Status:                 Subscribed

Use the --auto-attach option to automatically apply a subscription for the operating system.

List the available subscriptions and note the pool ID providing the Red Hat Certificate System. For example:

# subscription-manager list --available --all
...
Subscription Name:   Red Hat Enterprise Linux Developer Suite
Provides:            ...
                     Red Hat Certificate System
                     ...
Pool ID:             7aba89677a6a38fc0bba7dac673f7993
Available:           1
...

In case you have a lot of subscriptions, the output of the command can be very long. You can optionally redirect the output to a file:

# subscription-manager list --available --all > /root/subscriptions.txt

Attach the Certificate System subscription to the system using the pool ID from the previous step:

# subscription-manager attach --pool=7aba89677a6a38fc0bba7dac673f7993
Successfully attached a subscription for: Red Hat Enterprise Linux Developer Suite

Enable the Certificate Server repository:

# subscription-manager repos --enable=rhel-7-server-rhcmsys-9-rpms
Repository 'rhel-7-server-rhcmsys-9-rpms' is enabled for this system.

Installing the required packages is described in the Chapter 7, Installing and Configuring Certificate System chapter.

Note

For compliance, only enable Red Hat approved repositories. Only Red Hat approved repositories can be enabled through subscription-manager utility.

6.7. Certificate System Operating System Users and Groups

When installing Certificate System, the pkiuser account and the corresponding pkiuser group are automatically created. Certificate System uses this account and group to start services.

As part of a post-installation procedure, you will later be instructed to create an operating system user for each Certificate System administrator who should be able to start and stop or directly configure the instance on the operating system. For details, see the Section 7.10, “Post-installation Tasks”.

Chapter 7. Installing and Configuring Certificate System

Red Hat Certificate System provides different subsystems that can be installed individually. For example, you can install multiple subsystem instances on a single server or you can run them independently on different hosts. This enables you to adapt the installation to your environment to provide a higher availability, scalability, and fail-over support. This chapter describes the package installation and how to set up the individual subsystems.

The Certificate System includes the following subsystems:

Certificate Authority (CA)
Key Recovery Authority (KRA)
Online Certificate Status Protocol (OCSP) Responder
Token Key Service (TKS)
Token Processing System (TPS)

Each subsystem is installed and configured individually as a standalone Tomcat web server instance. However, Red Hat Certificate System additionally supports running a single shared Tomcat web server instance that can contain up to one of each subsystem.

7.1. Subsystem Configuration Order

The order in which the individual subsystems are set up is important because of relationships between the different subsystems:

At least one CA running as a security domain is required before any of the other public key infrastructure (PKI) subsystems can be installed.
Install the OCSP after the CA has been configured.
The KRA, and TKS subsystems can be installed in any order, after the CA and OCSP have been configured.
The TPS subsystem depends on the CA and TKS, and optionally on the KRA and OCSP subsystem.

Note

In certain situations, administrators want to install a standalone KRA or OCSP which do not require a CA running as a security domain. For details, see Section 7.9, “Setting up a Standalone KRA or OCSP”.

7.2. Certificate System Packages

When installing the Certificate System packages you can either install them for each subsystem individually or all at once.

Important

To install and update Certificate Server packages, you must enable the corresponding repository. For details, see Section 6.6, “Attaching a Red Hat Subscription and Enabling the Certificate System Package Repository”.

The following subsystem packages and components are available:

pki-ca: Provides the Certificate Authority (CA) subsystem.
pki-kra: Provides the Key Recovery Authority (KRA) subsystem.
pki-ocsp: Provides the Online Certificate Status Protocol (OCSP) responder.
pki-tks: Provides the Token Key Service (TKS).
pki-tps: Provides the Token Processing Service (TPS).
pki-console and redhat-pki-console-theme: Provides the Java-based Red Hat PKI console. Both packages must be installed.
pki-server and redhat-pki-server-theme: Provides the web-based Certificate System interface. Both packages must be installed.
This package is installed as a dependency if you install one of the following packages: pki-ca, pki-kra, pki-ocsp, pki-tks, pki-tps

Example 7.1. Installing Certificate System Packages

To install the CA subsystem and the optional web interface, enter:
```
# yum install pki-ca redhat-pki-server-theme
```
For other subsystems, replace the pki-ca package name with the one of the subsystem you want to install.

If you require the optional PKI console:

# yum install pki-console redhat-pki-console-theme

Alternatively, install all Certificate System subsystem packages and components automatically:
```
# yum install redhat-pki
```

7.2.1. Updating Certificate System Packages

To update Certificate System and operating system packages, use the following procedure:

Follow instructions in Section 7.2.2, “Determining Certificate System Product Version” to check the product version.
Execute # yum update
The command above updates the whole system including the RHCS packages.
Note
We suggest scheduling a maintenance window during which you can take the PKI infrastructure offline to install the update.
Important
Updating Certificate System requires the PKI infrastructure to be restarted.
Then check version again by following Section 7.2.2, “Determining Certificate System Product Version”.
The version number should confirm that the update was successfully installed.

To optionally download updates without installing, use the --downloadonly option in the above procedure:

yum update --downloadonly

The downloaded packages are stored in the /var/cache/yum/ directory. The yum update will later use the packages if they are the latest versions.

7.2.2. Determining Certificate System Product Version

The Red Hat Certificate System product version is stored in the /usr/share/pki/CS_SERVER_VERSION file. To display the version:

# cat /usr/share/pki/CS_SERVER_VERSION
Red Hat Certificate System 9.4 (Batch Update 3)

To find the product version of a running server, access the following URLs from your browser:

http://host_name:port_number/ca/admin/ca/getStatus
http://host_name:port_number/kra/admin/kra/getStatus
http://host_name:port_number/ocsp/admin/ocsp/getStatus
http://host_name:port_number/tks/admin/tks/getStatus
http://host_name:port_number/tps/admin/tps/getStatus

Note

Note that each component is a separate package and thus could have a separate version number. The above will show the version number for each currently running component.

7.3. Understanding the `pkispawn` Utility

In Red Hat Certificate System, you set up the individual public key infrastructure (PKI) subsystems using the pkispawn utility. During the setup, pkispawn:

Reads the default values from the /etc/pki/default.cfg file. For further details, see the pki_default.cfg(5) man page.
Important
Do not edit the /etc/pki/default.cfg file. Instead, create a configuration file and that overrides the defaults, and pass it to the pkispawn utility. For details about using a configuration file, see Section 7.7, “Two-step Installation”.
Uses the passwords and other deployment-specific information provided depending on the setup mode:
- Interactive mode: The user is asked for the individual settings during the setup. Use this mode for simple deployments.
- Batch mode: The values are read from a configuration file the user provides. Parameters not set in the configuration file use the defaults.
Performs the installation of the requested PKI subsystem.
Passes the settings to a Java servlet that performs the configuration based on the settings.

Use the pkispawn utility to install:

A root CA. For details, see Section 7.4, “Setting Up a Root Certificate Authority”.
A subordinate CA or any other subsystem. For details, see Section 7.6, “Setting up Additional Subsystems”.

Note

See Section 7.4, “Setting Up a Root Certificate Authority” on how to set up a root CA using the pkispawn utility. For a setup of a subordinate CA or non-CA subsystems, see Section 7.8, “Setting up Subsystems with an External CA”.

For further information about pkispawn and examples, see the pkispawn(8) man page.

7.4. Setting Up a Root Certificate Authority

The Certificate Authority (CA) subsystem is the prerequisite for all other Certificate System subsystems. Therefore, set up the CA before configuring other subsystems.

To set up a root CA in Certificate System, you have the following options:

Configuration file-based installation:
Use this method for high-level customization. This installation method uses a configuration file that overrides the default installation parameters.
You can install Certificate System using a configuration file in a single step or in two steps. For details and examples, see:
- The pkispawn(8) man page for the single-step installation.
- Section 7.7, “Two-step Installation” for the two-step installation.
Interactive installation:
```
# pkispawn -s CA
```
Use the interactive installer if you only want to set the minimum of required configuration options.

7.5. Post-Installation

Follow the procedures below:

Section 7.7.5.2, “Enabling Signed Audit Logging”
Section 13.4.1.1, “TLS Cipher Configuration”
Section 13.4.1.3, “Enabling Certificate Revocation Checking for Subsystems”

Once you completed the procedures above, follow Section 7.10, “Post-installation Tasks” for additional post-installation actions.

7.6. Setting up Additional Subsystems

After you have installed the root Certificate Authority (CA) as described in Section 7.4, “Setting Up a Root Certificate Authority”, you can install additional Certificate System subsystems.

Prerequisites

All additional subsystems require a root Certificate Authority (CA). If you have not installed a root Certificate System CA, see Section 7.4, “Setting Up a Root Certificate Authority”.

Installing the Subsystem

To set up an additional subsystem, you have the following options:

Configuration file-based installation:
Use this method for high-level customization. This installation method uses a configuration file that overrides the default installation parameters.
You can install Certificate System using a configuration file in a single step or in two steps. For details and examples, see:
- The pkispawn(8) man page for the single-step installation.
- Section 7.7, “Two-step Installation” for the two-step installation.
Interactive installation:
Use the interactive installer if you only want to set the minimum of required configuration options.
For example:
```
# pkispawn -s subsystem
```
Replace subsystem with one of the following subsystems: KRA, OCSP, TKS, or TPS.
The interactive installer does not support installing a subordinate CA. To install a subordinate CA, use the two-step installation. See Section 7.7, “Two-step Installation”.

7.7. Two-step Installation

To customize certain configuration parameters during installation, the installation process needs be done in two steps, with the configuration between them. For this, the pkispawn utility enables you to run the installation of a subsystem in two steps.

7.7.1. When to Use the Two-Step Installation

Use the two-step installation in scenarios such as:

Increasing security.
Customizing subsystem certificates.
Customizing the cipher list in the sslRangeCiphers parameter in the /etc/pki/instance_name/server.xml file when installing a new Certificate System instance to be connected to an existing Certificate System.
Installing CA clones, KRA, OCSP, TKS and TPS in FIPS mode.
Installing Certificate System with a Hardware Security Module (HSM) in FIPS mode.

7.7.2. The Two Major Parts of the Two-step Installation

The two-step installation consists of the following two major parts:

Installation
During this step, pkispawn copies configuration files from the /usr/share/pki/ directory to the instance-specific /etc/pki/instance_name/ directory. Additionally, pkispawn sets the settings based on values defined in the deployment configuration file.
This part of the installation contains the following substeps:
1. Section 7.7.3, “Creating the Configuration File for the First Step of the Installation”
2. Section 7.7.4, “Starting the Installation Step”
Configuration
During this step, pkispawn continues the installation based on the configuration files in the instance-specific /etc/pki/instance_name/ directory.
This part of the installation contains the following substeps:
1. Section 7.7.5, “Customizing the Configuration Between the Installation Steps”
2. Section 7.7.6, “Starting the Configuration Step”

7.7.3. Creating the Configuration File for the First Step of the Installation

Create a text file for the configuration settings, such as /root/config.txt, and fill it with the settings described below.

Important

This section describes a minimum configuration with Directory Server running on the same host as Certificate System. Depending on your environment, additional parameters may be necessary. For additional examples, see the EXAMPLES section in the pkispawn(8) man page.

For descriptions about the parameters covered in this section, see the pki_default.cfg(5) man page.

Subsystem-independent Settings

Independently of the subsystem you install, the following settings are required in the configuration file:

Set the passwords of the Certificate System admin user, the PKCS #12 file, and Directory Server:

[DEFAULT]
pki_admin_password=password
pki_client_pkcs12_password=password
pki_ds_password=password

To use an LDAPS connection to Directory Server running on the same host, add the following parameters to the [DEFAULT] section in the configuration file:
```
pki_ds_secure_connection=True
pki_ds_secure_connection_ca_pem_file=path_to_CA_or_self-signed_certificate
```
Note
For security reasons, Red Hat recommends using an encrypted connection to Directory Server.
If you use a self-signed certificate in Directory Server use the following command to export it from the Directory Server's Network Security Services (NSS) database:
```
# certutil -L -d /etc/dirsrv/slapd-instance_name/ \
     -n "server-cert" -a -o /root/ds.crt
```

Important

By default, Certificate System removes the ~/.dogtag/instance_name/subsystem/alias client database after the installation. For security reasons, Red Hat recommends not enabling the pki_client_database_purge parameter in the configuration file. If you manually set this parameter to True, Certificate System does not remove the client database after the installation.

After you created the initial configuration file, add the subsystem-specific settings to it. See:

the section called “CA Settings”
the section called “Settings for Other Subsystems”

CA Settings

In addition to the section called “Subsystem-independent Settings”, you need the following settings to install a CA:

To increase security, enable random serial numbers by adding the [CA] section with the following setting to the configuration file:
```
[CA]
pki_random_serial_numbers_enable=true
```
Optionally, set the following parameters in the [CA] section to specify the data of the admin user, which will be automatically created during the installation:
```
pki_admin_nickname=caadmin
pki_admin_name=CA administrator account
pki_admin_password=password
pki_admin_uid=caadmin
pki_admin_email=caadmin@example.com
```
Certificate System assigns administrator privileges to this account. Use this account after the installation to manage Certificate System and to create further user accounts.
To enable Certificate System to generate unique nicknames, set the following parameters in the [DEFAULT] section:
```
pki_instance_name=instance_name
pki_security_domain_name=example.com Security Domain
pki_host=server.example.com
```
Important
If you install Certificate System with a network-shared Hardware Security Module (HSM), you must use unique certificate nicknames.

Optionally, to use Elliptic Curve Cryptography (ECC) instead of RSA when generating certificates:

Add the following parameters to the [DEFAULT] section:

pki_admin_key_algorithm=SHA256withEC
pki_admin_key_size=nistp256
pki_admin_key_type=ecc
pki_sslserver_key_algorithm=SHA256withEC
pki_sslserver_key_size=nistp256
pki_sslserver_key_type=ecc
pki_subsystem_key_algorithm=SHA256withEC
pki_subsystem_key_size=nistp256
pki_subsystem_key_type=ecc

Add the following parameters to the [CA] section:

pki_ca_signing_key_algorithm=SHA256withEC
pki_ca_signing_key_size=nistp256
pki_ca_signing_key_type=ecc
pki_ca_signing_signing_algorithm=SHA256withEC
pki_ocsp_signing_key_algorithm=SHA256withEC
pki_ocsp_signing_key_size=nistp256
pki_ocsp_signing_key_type=ecc
pki_ocsp_signing_signing_algorithm=SHA256withEC

Add the following parameters to the [CA] section to override the RSA profiles with ECC profiles:

pki_source_admincert_profile=/usr/share/pki/ca/conf/eccAdminCert.profile
pki_source_servercert_profile=/usr/share/pki/ca/conf/eccServerCert.profile
pki_source_subsystemcert_profile=/usr/share/pki/ca/conf/eccSubsystemCert.profile

Settings for Other Subsystems

In addition to the section called “Subsystem-independent Settings”, you need the following settings to install a subordinate CA, KRA, OCSP, TKS, or TPS:

Add the following entry to [DEFAULT] section of your configuration file:
```
pki_client_database_password=password
```
If you are installing a TPS:
1. Add the following section with the following section:
```
[TPS]
pki_authdb_basedn=basedn_of_the_TPS_authentication_database
```
2. Optionally, to configure that the TPS use server-side key generation utilizing a KRA that has already been installed in the shared CA instance, add the following entry to the [TPS] section:
```
pki_enable_server_side_keygen=True
```

7.7.4. Starting the Installation Step

After you prepared the configuration file as described in Section 7.7.3, “Creating the Configuration File for the First Step of the Installation”, start the first step of the installation:

# pkispawn -f /root/config.txt -s subsystem --skip-configuration

Replace subsystem with one of the following subsystems: CA, KRA, OCSP, TKS, or TPS.

7.7.5. Customizing the Configuration Between the Installation Steps

After the installation step described in Section 7.7.4, “Starting the Installation Step” has finished successfully, you can manually update the instance-specific configuration files before the actual configuration begins. This section provides certain examples of what you can customize between the first and second step of the installation.

7.7.5.1. Configuring Certificate Profiles

In many cases, sites would want to customize certain certificate enrollment profiles (e.g. changing the default validity time of certificates), or to add/delete some profiles. For a complete list of options, see Chapter 15, Certificate Profiles Configuration.

7.7.5.2. Enabling Signed Audit Logging

The signed audit logging feature enables the detection of unauthorized log manipulation. For details, see Section 17.3.1, “Enabling and Configuring Signed Audit Log”.

7.7.5.3. Updating the Ciphers List

In certain situations, administrators want to update the ciphers list. For example:

To secure the Certificate System instance
To install a Certificate System instance and to add it to an existing site that supports only specific ciphers

For details on updating the cipher list, see Section 13.4.1.1.1, “Client TLS cipher Configuration”.

Default FIPS Mode Enabled Ciphers for RSA Encryption

By default, Certificate System contains the following FIPS mode enabled ciphers for RSA encryption:

TLS_DHE_RSA_WITH_AES_128_CBC_SHA
TLS_DHE_RSA_WITH_AES_128_CBC_SHA256
TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
TLS_DHE_RSA_WITH_AES_256_CBC_SHA
TLS_DHE_RSA_WITH_AES_256_CBC_SHA256
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
TLS_RSA_WITH_AES_128_CBC_SHA
TLS_RSA_WITH_AES_128_CBC_SHA256
TLS_RSA_WITH_AES_256_CBC_SHA
TLS_RSA_WITH_AES_256_CBC_SHA256

Default FIPS Mode Enabled Ciphers for ECC Encryption

By default, Certificate System contains the following FIPS mode enabled ciphers for Elliptic Curve Cryptography (ECC) encryption:

TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
TLS_RSA_WITH_AES_256_CBC_SHA
TLS_RSA_WITH_AES_256_CBC_SHA256

Required RSA Ciphers When Running an HSM on System with FIPS Mode Enabled

If you install Certificate System with either LunaSA or Hardware Security Module (HSM) on systems with FIPS mode enabled for RSA, disable the following ciphers, as they are unsupported on HSMs:

TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA

7.7.5.4. Configuring the PKI Console Timeout

For details on configuring the PKI console timeout, see the corresponding section in Section 13.4.2, “Session Timeout”.

7.7.5.5. Setting the KRA into Encryption Mode

If you are using a Hardware Security Module (HSM), it is necessary in certain situations to set the Key Recovery Authority (KRA) into encryption mode. For details, see the section called “Setting the KRA into Encryption Mode”.

7.7.5.6. Enabling OCSP

For details about enabling the Online Certificate Status Protocol (OCSP) see Section 13.4.1.3, “Enabling Certificate Revocation Checking for Subsystems”.

7.7.5.7. Configuring Ranges for Requests and Serial Numbers

For details about configuring ranges for requests and serial numbers, see Section 13.2.3.14, “Configuring Ranges for Requests and Serial Numbers”.

7.7.6. Starting the Configuration Step

After you have customized the configuration files according to Section 7.7.5, “Customizing the Configuration Between the Installation Steps”, start the second step of the installation:

# pkispawn -f /root/config.txt -s subsystem --skip-installation

Replace subsystem with one of the following subsystems: CA, KRA, OCSP, TKS, or TPS.

If the configuration step succeeds, the pkispawn utility displays an installation summary. For example:

================================================================
                       INSTALLATION SUMMARY
================================================================

  Administrator's username:             caadmin
  Administrator's PKCS #12 file:
        /root/.dogtag/instance_name/ca_admin_cert.p12

  To check the status of the subsystem:
        systemctl status pki-tomcatd@instance_name.service

  To restart the subsystem:
        systemctl restart pki-tomcatd@instance_name.service

  The URL for the subsystem is:
        https://server.example.com:8443/ca/

  PKI instances will be enabled upon system boot

================================================================

7.7.7. Post-Installation

Once you completed the procedures above, follow Section 7.10, “Post-installation Tasks” for additional post-installation actions.

7.8. Setting up Subsystems with an External CA

7.8.1. The Difference Between an Internal and External CA

In Red Hat Certificate System, when the pkispawn utility sends subsystem Certificate Signing Requests (CSR) to a previously installed Certificate System, and the resulting issued certificates are received and used by pkispawn, the CA the CSRs were sent to is called an Internal CA.

An External CA, by contrast, can be one of the following:

A non-Red Hat Certificate System CA that issues the signing certificate for a Certificate System subordinate CA.
A previously installed Red Hat Certificate System CA that does not allow direct submission of CSRs. For example, this is the case if your environment requires CSRs from a subordinate CA, KRA, OCSP, TKS, or TPS to be in other formats than PKCS #10.

7.8.2. Installing a Subsystem with an External CA

This section describes how to set up a subordinate CA or other subsystems whose certificate will be signed by an external CA.

Preparing the Configuration File for the External CA Installation

Prepare the configuration file depending on whether you want your subsystem to be integrated into Certificate System or standalone:

If you install a subsystem which is integrated into an existing Certificate System installation but which uses a certificate signed by an external CA:

Create the configuration file for the subsystem. See Section 7.7.3, “Creating the Configuration File for the First Step of the Installation”.

Add the following settings to your configuration file:

For a CA installation:

pki_external=True
pki_external_step_two=False

pki_ca_signing_csr_path=path/to/ca_signing.csr
pki_ca_signing_cert_path=path/to/ca_signing.crt

For a KRA installation:

pki_external=True
pki_external_step_two=False

pki_storage_csr_path=/home/user_name/kra_storage.csr
pki_transport_csr_path=/home/user_name/kra_transport.csr
pki_subsystem_csr_path=/home/user_name/subsystem.csr
pki_sslserver_csr_path=/home/user_name/sslserver.csr
pki_audit_signing_csr_path=/home/user_name/kra_audit_signing.csr
pki_admin_csr_path=/home/user_name/kra_admin.csr

For an OCSP installation:

pki_external=True
pki_external_step_two=False

pki_ocsp_signing_csr_path=/home/user_name/ocsp_signing.csr
pki_subsystem_csr_path=/home/user_name/subsystem.csr
pki_sslserver_csr_path=/home/user_name/sslserver.csr
pki_audit_signing_csr_path=/home/user_name/ocsp_audit_signing.csr
pki_admin_csr_path=/home/user_name/ocsp_admin.csr

If you install a standalone KRA or OCSP, which is not integrated into an existing Certificate System installation, execute the steps described in Section 7.9, “Setting up a Standalone KRA or OCSP”.

Starting the Installation of a Subsystem with an External CA

To start the installation with the configuration file:

Use the pkispawn utility to start the installation:
```
# pkispawn -f /root/config.txt -s subsystem
```
Replace subsystem with the subsystem you want to install: CA, KRA, or OCSP.
During this step, the setup stores the CSRs in the files specified in the configuration.
Submit the CSRs to the external CA. Proceed after the CA has issued the corresponding certificates.
In certain environments, if the external CA is also a Certificate System instance, the CSR in PKCS#10 format needs to be converted into CMC format before being submitted to the CA. See the Issuing Certificates Using CMC section in the Red Hat Certificate System Administration Guide for details about issuing the certificates.
Optionally, customize the installation. For details, see Section 7.7.5, “Customizing the Configuration Between the Installation Steps”.

After the external CA has issued the certificates, edit the deployment configuration file:

Set the pki_external_step_two to True:
```
pki_external_step_two=True
```

Add the following parameters, based on the subsystem you are installing:

For a CA, set the path to the certificate file. For example:
```
pki_ca_signing_cert_path=/home/user_name/ca_signing.crt
```
If the specified file does not contain the certificate including the certificate chain, additionally specify the path to the certificate chain file and its nickname. For example:
```
pki_cert_chain_path=/home/user_name/cert_chain.p7b
pki_cert_chain_nickname=CA Signing Certificate
```

For a KRA, set the paths to the certificate files. For example:

pki_storage_cert_path=/home/user_name/kra_storage.crt
pki_transport_cert_path=/home/user_name/kra_transport.crt
pki_subsystem_cert_path=/home/user_name/subsystem.crt
pki_sslserver_cert_path=/home/user_namesslserver.crt
pki_audit_signing_cert_path=/home/user_name/kra_audit_signing.crt
pki_admin_cert_path=/home/user_name/kra_admin.crt

If the specified files do not contain the certificate including the certificate chain, additionally specify the paths to the signing certificate file and the certificate chain file together with their nicknames. For example:

pki_ca_signing_nickname=CA Signing Certificate
pki_ca_signing_cert_path=/home/user_name/ca_signing.crt
pki_cert_chain_nickname=External Certificate Chain
pki_cert_chain_path=/home/user_name/cert_chain.p7b

For an OCSP, set the paths to the certificate files. For example:

pki_ocsp_signing_cert_path=/home/user_name/ocsp_signing.crt
pki_subsystem_cert_path=/home/user_name/subsystem.crt
pki_sslserver_cert_path=/home/user_name/sslserver.crt
pki_audit_signing_cert_path=/home/user_name/ocsp_audit_signing.crt
pki_admin_cert_path=/home/user_name/ocsp_admin.crt

pki_ca_signing_nickname=CA Signing Certificate
pki_ca_signing_cert_path=/home/user_name/ca_signing.crt
pki_cert_chain_nickname=External Certificate Chain
pki_cert_chain_path=/home/user_name/cert_chain.p7b

Optionally, customize the configuration files. For examples, see Section 7.7.5, “Customizing the Configuration Between the Installation Steps”.
Start the configuration step:
```
# pkispawn -f /root/config.txt -s subsystem
```
Replace subsystem with the subsystem you want to install: CA, KRA, or OCSP.

7.8.3. Post-Installation

Once you completed the procedures above, follow Section 7.10, “Post-installation Tasks” for additional post-installation actions.

7.9. Setting up a Standalone KRA or OCSP

This section describes how to install a standalone KRA and OCSP. A standalone installation provides the flexibility to use a non-Certificate System CA to issue the certificates, because the CSRs generated during the installation are not automatically submitted to the CA and imported into the subsystem. Additionally, a KRA or an OCSP installed in standalone mode is not part of the CA's security domain, and the connector in the CA for key archival will not be configured.

To install a standalone KRA or OCSP:

Create a configuration file, such as /root/config.txt, with the following content:

[DEFAULT]
pki_admin_password=password
pki_client_database_password=password
pki_client_pkcs12_password=password
pki_ds_password=password
pki_token_password=password
pki_client_database_purge=False
pki_security_domain_name=EXAMPLE

pki_standalone=True
pki_external_step_two=False

For a standalone KRA, add the following section to the configuration file:

[KRA]
pki_admin_email=kraadmin@example.com
pki_ds_base_dn=dc=kra,dc=example,dc=com
pki_ds_database=kra

pki_admin_nickname=kraadmin
pki_audit_signing_nickname=kra_audit_signing
pki_sslserver_nickname=sslserver
pki_storage_nickname=kra_storage
pki_subsystem_nickname=subsystem
pki_transport_nickname=kra_transport

pki_standalone=True

For a standalone OCSP, add the following section to the configuration file:

[OCSP]
pki_admin_email=ocspadmin@example.com
pki_ds_base_dn=dc=ocsp,dc=example,dc=com
pki_ds_database=ocsp

pki_admin_nickname=ocspadmin
pki_audit_signing_nickname=ocsp_audit_signing
pki_ocsp_signing_nickname=ocsp_signing
pki_sslserver_nickname=sslserver
pki_subsystem_nickname=subsystem

pki_standalone=True

To use an LDAPS connection to Directory Server running on the same host, add the following parameters to the DEFAULT section in the configuration file:
```
pki_ds_secure_connection=True
pki_ds_secure_connection_ca_pem_file=path_to_CA_or_self-signed_certificate
```
Note
For security reasons, Red Hat recommends using an encrypted connection to Directory Server.
If you use a self-signed certificate in Directory Server, use the following command to export it from the Directory Server's Network Security Services (NSS) database:
```
# certutil -L -d /etc/dirsrv/slapd-instance_name/ \
     -n "server-cert" -a -o /root/ds.crt
```
Proceed with the steps described in the section called “Starting the Installation of a Subsystem with an External CA”.

7.10. Post-installation Tasks

Once installation using the pkispawn utility is complete, further steps could be taken to customize the configuration, depending on the site's preferences. These are described in Part III, “Configuring Certificate System”.

This section provides a list of operations from Part III, “Configuring Certificate System” which are suggested for improving the security for the deployment.

7.10.1. Setting Date/Time for RHCS

It is important to have the time set up correctly for running RHCS; see the Setting Time and Date section in the Red Hat Certificate System Administration Guide.

7.10.2. Replacing a Temporary Self-Signed Certificate in Directory Server (CA)

If the internal LDAP server was initially created with a temporary self-signed server certificate, refer to Section 6.5.3, “Replacing the Temporary Certificate” to replace it with a new certificate issued by the CA you just installed.

7.10.3. Enabling TLS Client Authentication for the Internal LDAP Server

Red Hat Certificate System can communicate with its internal LDAP server via TLS mutual authentication. For further details, see Section 6.5.4, “Enabling TLS Client Authentication”.

7.10.4. Configuring Session Timeout

Various timeout configurations exist on the system that could affect how long a TLS session is allowed to remain idle before termination. For details, see Section 13.4.2, “Session Timeout”.

7.10.5. CRL or Certificate Publishing

CRL publishing is critical in providing OCSP service. Certificate publishing is optional but often desired by sites. For details, see the Publishing Certificates and CRLs section in the Red Hat Certificate System Administration Guide.

7.10.6. Configuring Certificate Enrollment Profiles (CA)

RHCS has a rich profile framework that allows for customization of the certificate enrollment profiles. It is very common for a site to enable/disable default profiles that come with the system, or modify existing profiles, or create their own profiles. For details, see Chapter 15, Certificate Profiles Configuration.

7.10.7. Enabling Access Banner

To enable user interface banners, refer to Section 13.7.1, “Enabling an Access Banner”.

7.10.8. Enabling the Watchdog Service

The watchdog (nuxwdog) service provides secure system password management. For details, see Section 13.3.2.1, “Enabling the Watchdog Service”.

7.10.9. Configuration for CMC Enrollment and Revocation (CA)

Certificate enrollments and revocation can be done via CMC.

For details about enabling the CMC Shared Token Feature, see Section 13.8.3, “Enabling the CMC Shared Secret Feature”.
For details about enabling the PopLinkWittness feature, see Section 13.8.2, “Enabling the PopLinkWittnessV2 Feature”.
For details about enabling CMCRevoke for the web user interface, see Section 13.8.4, “Enabling CMCRevoke for the Web User Interface”.

7.10.10. TLS client-authentication for the Java Console

To require Certificate System administrators to present a user TLS client certificate when logging into the Java console, see Section 13.2.3.15, “Setting Requirement for pkiconsole to use TLS Client Certificate Authentication”.

7.10.11. Creating a Role User

Create real role users so that you can remove the bootstrap user.

To create users and assign them to different privileged roles to manage Certificate System, see Chapter 18, Creating a Role User.

7.10.12. Removing the Bootstrap User

Once the real role users are created, the bootstrap user that was created automatically during the installation is not needed anymore. To delete this account, see Chapter 19, Deleting the Bootstrap User after making sure you created a new administrator account assigned to an individual person.

7.10.13. Disabling Multi-role Support

To disable the multi-role support once the bootstrap user is removed, see Section 19.1, “Disabling Multi-roles Support”.

7.10.14. KRA Configurations

7.10.14.1. Adding Requirement for Multiple Agent Approval for Key Recovery Authority (KRA)

To set up a requirement for multiple KRA agents to approve key recovery, see the Configuring Agent-Approved Key Recovery in the Command Line section in the Red Hat Certificate System Administration Guide.

7.10.14.2. Configuring KRA Encryption Settings

To configure key encryption/wrapping algorithms, see Section 16.2, “Encryption Of KRA Operations”.

7.10.15. Setting up Users to use User Interfaces

Before a user could use an approved user interface, initialization needs to be performed. Users (administrative roles or otherwise) are required to setup their clients for accessing the user interface. See the Client NSS Database Initialization section in the Red Hat Certificate System Administration Guide.

Chapter 8. Using Hardware Security Modules for Subsystem Security Databases

A subsystem instance generates and stores its key information in a key store, called a security module or a token. A subsystem instance can be configured for the keys to be generated and stored using the internal NSS token or on a separate cryptographic device, a hardware token.

8.1. Installing Certificate System with an HSM

Use the following parameters in the configuration file you pass to the pkispawn utility when installing Certificate System with an HSM:

[DEFAULT]
##########################
# Provide HSM parameters #
##########################
pki_hsm_enable=True
pki_hsm_libfile=hsm_libfile
pki_hsm_modulename=hsm_modulename
pki_token_name=hsm_token_name
pki_token_password=pki_token_password

########################################
# Provide PKI-specific HSM token names #
########################################
pki_audit_signing_token=hsm_token_name
pki_ssl_server_token=hsm_token_name
pki_subsystem_token=hsm_token_name

8.2. Using Hardware Security Modules with Subsystems

The Certificate System supports the nCipher nShield hardware security module (HSM) and Gemalto Safenet LunaSA HSM by default. Certificate System-supported HSMs are automatically added to the secmod.db database with the modutil command during the pre-configuration stage of the installation, if the PKCS #11 library modules are in the specified installation paths.

Important

Certain deployments require to setup their HSM to use FIPS mode.

8.2.1. Enabling the FIPS Mode on an HSM

To enable FIPS Mode on HSMs, please refer to your HSM vendor's documentation for specific instructions.

Important

nCipher HSM: On a nCipher HSM, the FIPS mode can only be enabled when generating the Security World, this cannot be changed afterwards. While there is a variety of ways to generate the Security World, the preferred method is always to use the new-world command. For guidance on how to generate a FIPS-compliant Security World, please follow the nCipher HSM vendor's documentation.
LunaSA HSM: Similarly, enabling the FIPS mode on a Luna HSM must be done during the initial configuration, since changing this policy zeroizes the HSM as a security measure. For details, please refer to the Luna HSM vendor's documentation.

8.2.2. Verifying if FIPS Mode is Enabled on an HSM

This section describes how to verify if FIPS mode is enabled for certain HSMs. For other HSMs, see the hardware manufacturer's documentation.

8.2.2.1. Verifying if FIPS Mode is Enabled on an nCipher HSM

Note

Please refer to your HSM vendor’s documentation for the complete procedure.

To verify if the FIPS mode is enabled on an nCipher HSM, enter:

# /opt/nfast/bin/nfkminfo

8.2.2.2. Verifying if FIPS Mode is Enabled on a Luna SA HSM

Note

Please refer to your HSM vendor’s documentation for the complete procedure.

To verify if the FIPS mode is enabled on a Luna SA HSM:

Open the lunash management console

Use the hsm show command and verify that the output contains the text The HSM is in FIPS 140-2 approved operation mode.:

lunash:> hsm show
...
			 FIPS 140-2 Operation:
			 =====================
			 The HSM is in FIPS 140-2 approved operation mode.
...

8.2.3. Adding or Managing the HSM Entry for a Subsystem

During installation, when an HSM is selected as the default token where appropriate HSM-specific parameters are set in the configuration file passed to the pkispawn command, the following parameter is added to the /var/lib/pki/instance_name/conf/password.conf file for the HSM password:

hardware-HSM_token_name=HSM_token_password

8.2.4. Setting up SELinux for an HSM

If you want to install Certificate System with an Hardware Security Modules (HSM) and SELinux is running in enforcing mode, certain HSMs require that you manually update SELinux settings before you can install Certificate System.

The following section describes the required actions for supported HSMs:

nCipher nShield

After you installed the HSM and before you start installing Certificate System:

Reset the context of files in the /opt/nfast/ directory:
```
# restorecon -R /opt/nfast/
```

Restart the nfast software.

# /opt/nfast/sbin/init.d-ncipher restart

Gemalto Safenet LunaSA HSM

No SELinux-related actions are required before you start installing Certificate System.

8.2.5. Installing a Subsystem Using nCipher nShield HSM

To install a subsystem instance that use nCipher nShield HSM, follow this procedure:

Prepare an override file, which corresponds to your particular deployment. The following default_hms.txt file is an example of such an override file:

Note

This file serves only as an example of an nCipher HSM override configuration file -- numerous other values can be overridden including default hashing algorithms. Also, only one of the [CA], [KRA], [OCSP], [TKS], or [TPS] sections will be utilized depending upon the subsystem invocation specified on the pkispawn command-line.

Example 8.1. An Override File Sample to Use with nCipher HSM


###############################################################################
###############################################################################
###############################################################################
##                                                                           ##
## EXAMPLE: Configuration File used to override '/etc/pki/default.cfg'       ##
##          when using an nCipher Hardware Security Module (HSM):            ##
##                                                                           ##
##                                                                           ##
##     # modutil -dbdir . -list                                              ##
##                                                                           ##
##     Listing of PKCS #11 Modules                                           ##
##     -----------------------------------------------------------           ##
##       1. NSS Internal PKCS #11 Module                                     ##
##              slots: 2 slots attached                                      ##
##             status: loaded                                                ##
##                                                                           ##
##              slot: NSS Internal Cryptographic Services                    ##
##             token: NSS Generic Crypto Services                            ##
##                                                                           ##
##              slot: NSS User Private Key and Certificate Services          ##
##             token: NSS Certificate DB                                     ##
##                                                                           ##
##      2. nfast                                                             ##
##            library name: /opt/nfast/toolkits/pkcs11/libcknfast.so         ##
##             slots: 2 slots attached                                       ##
##            status: loaded                                                 ##
##                                                                           ##
##             slot: <serial_number> Rt1                                     ##
##            token: accelerator                                             ##
##                                                                           ##
##             slot: <serial_number> Rt1 slot 0                              ##
##            token: <HSM_token_name>                                        ##
##     -----------------------------------------------------------           ##
##                                                                           ##
##                                                                           ##
##     Based on the example above, substitute all password values,           ##
##     as well as the following values:                                      ##
##                                                                           ##
##         <hsm_libfile>=/opt/nfast/toolkits/pkcs11/libcknfast.so            ##
##         <hsm_modulename>=nfast                                            ##
##         <hsm_token_name>=NHSM6000                                         ##
##                                                                           ##
###############################################################################
###############################################################################
###############################################################################

[DEFAULT]
##########################
# Provide HSM parameters #
##########################
pki_hsm_enable=True
pki_hsm_libfile=<hsm_libfile>
pki_hsm_modulename=<hsm_modulename>
pki_token_name=<hsm_token_name>
pki_token_password=<pki_token_password>

########################################
# Provide PKI-specific HSM token names #
########################################
pki_audit_signing_token=<hsm_token_name>
pki_ssl_server_token=<hsm_token_name>
pki_subsystem_token=<hsm_token_name>

##################################
# Provide PKI-specific passwords #
##################################
pki_admin_password=<pki_admin_password>
pki_client_pkcs12_password=<pki_client_pkcs12_password>
pki_ds_password=<pki_ds_password>

#####################################
# Provide non-CA-specific passwords #
#####################################
pki_client_database_password=<pki_client_database_password>

###############################################################
# ONLY required if specifying a non-default PKI instance name #
###############################################################
#pki_instance_name=<pki_instance_name>

##############################################################
# ONLY required if specifying non-default PKI instance ports #
##############################################################
#pki_http_port=<pki_http_port>
#pki_https_port=<pki_https_port>

######################################################################
# ONLY required if specifying non-default 389 Directory Server ports #
######################################################################
#pki_ds_ldap_port=<pki_ds_ldap_port>
#pki_ds_ldaps_port=<pki_ds_ldaps_port>

######################################################################
# ONLY required if PKI is using a Security Domain on a remote system #
######################################################################
#pki_ca_hostname=<pki_ca_hostname>
#pki_issuing_ca_hostname=<pki_issuing_ca_hostname>
#pki_issuing_ca_https_port=<pki_issuing_ca_https_port>
#pki_security_domain_hostname=<pki_security_domain_hostname>
#pki_security_domain_https_port=<pki_security_domain_https_port>

###########################################################
# ONLY required for PKI using an existing Security Domain #
###########################################################
# NOTE:  pki_security_domain_password == pki_admin_password
#        of CA Security Domain Instance
#pki_security_domain_password=<pki_admin_password>


[Tomcat]
##############################################################
# ONLY required if specifying non-default PKI instance ports #
##############################################################
#pki_ajp_port=<pki_ajp_port>
#pki_tomcat_server_port=<pki_tomcat_server_port>


[CA]
#######################################
# Provide CA-specific HSM token names #
#######################################
pki_ca_signing_token=<hsm_token_name>
pki_ocsp_signing_token=<hsm_token_name>

###########################################################################
# ONLY required if 389 Directory Server for CA resides on a remote system #
###########################################################################
#pki_ds_hostname=<389 hostname>


[KRA]
########################################
# Provide KRA-specific HSM token names #
########################################
pki_storage_token=<hsm_token_name>
pki_transport_token=<hsm_token_name>

############################################################################
# ONLY required if 389 Directory Server for KRA resides on a remote system #
############################################################################
#pki_ds_hostname=<389 hostname>


[OCSP]
#########################################
# Provide OCSP-specific HSM token names #
#########################################
pki_ocsp_signing_token=<hsm_token_name>

#############################################################################
# ONLY required if 389 Directory Server for OCSP resides on a remote system #
#############################################################################
#pki_ds_hostname=<389 hostname>


[TKS]
########################################
# Provide TKS-specific HSM token names #
########################################

############################################################################
# ONLY required if 389 Directory Server for TKS resides on a remote system #
############################################################################
#pki_ds_hostname=<389 hostname>


[TPS]
###################################
# Provide TPS-specific parameters #
###################################
pki_authdb_basedn=<dnsdomainname where hostname.b.c.d is dc=b,dc=c,dc=d>

########################################
# Provide TPS-specific HSM token names #
########################################

############################################################################
# ONLY required if 389 Directory Server for TPS resides on a remote system #
############################################################################
#pki_ds_hostname=<389 hostname>

##########################################################
# ONLY required if TPS requires a CA on a remote machine #
##########################################################
#pki_ca_uri=https://<pki_ca_hostname>:<pki_ca_https_port>

#######################################
# ONLY required if TPS requires a KRA #
#######################################
#pki_enable_server_side_keygen=True

###########################################################
# ONLY required if TPS requires a KRA on a remote machine #
###########################################################
#pki_kra_uri=https://<pki_kra_hostname>:<pki_kra_https_port>

###########################################################
# ONLY required if TPS requires a TKS on a remote machine #
###########################################################
#pki_tks_uri=https://<pki_tks_hostname>:<pki_tks_https_port>

Use the configuration file as described in Section 7.7, “Two-step Installation”.

# pkispawn -s CA -f ./default_hsm.txt -vvv

# pkispawn -s KRA -f ./default_hsm.txt -vvv

# pkispawn -s OCSP -f ./default_hsm.txt -vvv

# pkispawn -s TKS -f ./default_hsm.txt -vvv

# pkispawn -s TPS -f ./default_hsm.txt -vvv

8.2.6. Installing a Subsystem Using Gemalto Safenet LunaSA HSM

To install a subsystem instance that use Gemalto Safenet LunaSA HSM, follow the procedure detailed in Section 8.2.5, “Installing a Subsystem Using nCipher nShield HSM”. The override file should be similar to the sample provided in Example 8.1, “An Override File Sample to Use with nCipher HSM”, differing in values related to the particular deployment. The following example provides a sample LunaSA header that is to be substituted for the header of the nCipher override file and to be used with the [DEFAULT], [Tomcat], [CA], [KRA], [OCSP], [TKS], and [TPS] sections provided in the aforementioned nCipher example.

Example 8.2. A Sample of the LunaSA Override File Header


###############################################################################
###############################################################################
###############################################################################
##                                                                           ##
## EXAMPLE: Configuration File used to override '/etc/pki/default.cfg'       ##
##          when using a LunaSA Hardware Security Module (HSM):              ##
##                                                                           ##
##                                                                           ##
##     # modutil -dbdir . -list                                              ##
##                                                                           ##
##     Listing of PKCS #11 Modules                                           ##
##     -----------------------------------------------------------           ##
##       1. NSS Internal PKCS #11 Module                                     ##
##              slots: 2 slots attached                                      ##
##             status: loaded                                                ##
##                                                                           ##
##              slot: NSS Internal Cryptographic Services                    ##
##             token: NSS Generic Crypto Services                            ##
##                                                                           ##
##              slot: NSS User Private Key and Certificate Services          ##
##             token: NSS Certificate DB                                     ##
##                                                                           ##
##      2. lunasa                                                            ##
##            library name: /usr/safenet/lunaclient/lib/libCryptoki2_64.so   ##
##             slots: 4 slots attached                                       ##
##            status: loaded                                                 ##
##                                                                           ##
##             slot: LunaNet Slot                                            ##
##            token: dev-intca                                               ##
##                                                                           ##
##             slot: Luna UHD Slot                                           ##
##            token:                                                         ##
##                                                                           ##
##             slot: Luna UHD Slot                                           ##
##            token:                                                         ##
##                                                                           ##
##             slot: Luna UHD Slot                                           ##
##            token:                                                         ##
##     -----------------------------------------------------------           ##
##                                                                           ##
##                                                                           ##
##     Based on the example above, substitute all password values,           ##
##     as well as the following values:                                      ##
##                                                                           ##
##         <hsm_libfile>=/usr/safenet/lunaclient/lib/libCryptoki2_64.so      ##
##         <hsm_modulename>=lunasa                                           ##
##         <hsm_token_name>=dev-intca                                        ##
##                                                                           ##
###############################################################################
###############################################################################
###############################################################################

8.3. Backing up Keys on Hardware Security Modules

It is not possible to export keys and certificates stored on an HSM to a .p12 file. If such an instance is to be backed-up, contact the manufacturer of your HSM for support.

8.4. Installing a Clone Subsystem Using an HSM

Normally, clone subsystems are created using a PKCS #12 file containing the system keys of the master subsystem. This file is generated during the installation of the master subsystem by setting the pki_backup_keys to True in the configuration file you use for the installation along with the defined value for the pki_backup_password option, or by exporting the keys using the PKCS12Export tool.

You cannot generate a PKCS #12 file using this tool when using an HSM because the keys cannot be retrieved from the HSM. Instead, the clone subsystem should either be pointed to the HSM used by the master subsystem, so that it can access the same keys. Alternatively, if using a separate HSM, clone the keys to this HSM using the utilities provided by the HSM vendor. You must provide access to the master subsystem's key before running the pkispawn utility.

As Certificate System uses no PKCS #12 when installing with an HSM, you do not need to set the parameters in the configuration file for the location of a PKCS #12 file and its password. The following example lists options from the [Tomcat] section of the respective PKI configuration file that are required for generating a CA clone.

For generating a non-HSM CA clone:

pki_clone=True
pki_clone_pkcs12_password=Secret123
pki_clone_pkcs12_path=<path_to_pkcs12_file>
pki_clone_replicate_schema=True (default value)
pki_clone_uri=https://<master_ca_host_name>:<master_ca_https_port>

For generating a CA clone using an HSM:

pki_clone=True
pki_clone_replicate_schema=True (default value)
pki_clone_uri=https://<master_ca_host_name>:<master_ca_https_port>

Note

In order for the master subsystem to share the same certificates and keys with its clones, the HSM must be on a network that is in shared mode and accessible by all subsystems.

8.5. Viewing Tokens

To view a list of the tokens currently installed for a Certificate System instance, use the modutil utility.

Change to the instance alias directory. For example:
```
# cd /var/lib/pki/pki-tomcat/alias
```
Show the information about the installed PKCS #11 modules installed as well as information on the corresponding tokens using the modutil tool.
```
# modutil -dbdir . -nocertdb -list
```

8.6. Detecting Tokens

To see if a token can be detected by Certificate System, use the TokenInfo utility, pointing to the alias directory for the subsystem instance. This is a Certificate System tool which is available after the Certificate System packages are installed.

For example:

# TokenInfo /var/lib/pki/pki-tomcat/alias

This utility returns all tokens which can be detected by the Certificate System, not only tokens which are installed in the Certificate System.

8.7. Failover and Resilience

Failover means setting up multiple units, and configuring them so that if one unit fails, another one will take over and continue the service without interruption.

Resilience ensures that when the network connection to a unit is interrupted and then reconnected, the service is not interrupted within a reasonable timeframe.

Some Hardware Security Module (HSM) models offer failover or resilience of varying degrees. For detail on the exact make and models and the features that they offer, consult your HSM manual, or contact the manufacturer. The HSMs described in the following sections have been tested with Red Hat Certificate System.

8.7.1. nCipher nShield HSM

8.7.1.1. Failover

With nShield Connect 6000, failover has been tested in the scenario where there are two HSM modules, nShield1, and nShield2, both running and configured for failover.

If one of nShield units goes down, the other exhibits ability to continue the provision of cryptographic services to Certificate System with no known issues, without restarting of the RHCS instance.

When the above situation happens (one HSM unit goes down), the administrator is expected to schedule a downtime for all the connected Certificate System instances and fix the down hsm unit and bring it back up and restart the instances. This means that if one unit goes down, Certificate System is expected to continue functioning; however, if the down hsm is brought back up without restarting the instances, the newly brought up HSM unit is not expected to be part of the failover scheme as originally planned.

8.7.1.2. Resilience

With nShield Connect 6000, testing has shown that when the network cable is pulled off the HSM unit, and replugged in within up to 90 minutes, the service continues. There is no data for any time period longer than 90 minutes.

8.7.2. Gemalto Safenet LunaSA HSM

8.7.2.1. Failover

The Gemalto Safenet LunaSA Cloning model offers Failover. However, we have no data on this model.

Chapter 9. Installing an Instance with ECC System Certificates

Elliptic curve cryptography (ECC) may be preferred over RSA-style encryption in some cases, as it allows it to use much shorter key lengths and makes it faster to generate certificates. CAs which are ECC-enabled can issue both RSA and ECC certificates, using their ECC signing certificate.

Certificate System includes native support for ECC features; the support is enabled by default starting from NSS 3.16. It is also possible to load and use a third-party PKCS #11 module, such as a hardware security module (HSM). To use the ECC module, it must be loaded before the subsystem instance is configured.

Important

Third-party ECC modules must have an SELinux policy configured for them, or SELinux needs to be changed from enforcing mode to permissive mode to allow the module to function. Otherwise, any subsystem operations which require the ECC module will fail.

9.1. Loading a Third-Party ECC Module

Loading a third-party ECC module follows the same principles as loading HSMs supported by Certificate System, which is described in Chapter 8, Using Hardware Security Modules for Subsystem Security Databases. See this chapter for more information.

9.2. Using ECC with an HSM

The HSMs supported by Certificate System support their own native ECC modules. To create an instance with ECC system certificates:

Set up the HSM per manufacturer's instructions. If multiple hosts are sharing the HSM, make sure they can all access the same partition if needed and if the site policies allow it.
Define the required parameters in the pkispawn utility configuration file and run pkispawn. For example, to configure Certificate System to create an ECC CA, assuming the configuration file is ecc.inf:
1. Edit ecc.inf to specify the appropriate settings. For an example of the configuration file, see the pkispawn(8) man page.
2. Run pkispawn against ecc.inf:
```
$ script -c 'pkispawn -s CA -f /root/pki/ecc.inf -vvv'
```

Chapter 10. Cloning Subsystems

When a new subsystem instance is first configured, the Red Hat Certificate System allows subsystems to be cloned, or duplicated, for high availability of the Certificate System. The cloned instances run on different machines to avoid a single point of failure and their databases are synchronized through replication.

The master CA and its clones are functionally identical, they only differ in serial number assignments and CRL generation. Therefore, this chapter refers to master or any of its clones as replicated CAs.

10.1. Backing up Subsystem Keys from a Software Database

Ideally, the keys for the master instance are backed up when the instance is first created. If the keys were not backed up then or if the backup file is lost, then it is possible to extract the keys from the internal software database for the subsystem instance using the PKCS12Export utility. For example:

PKCS12Export -debug -d /var/lib/pki/instance_name/alias -w p12pwd.txt -p internal.txt -o master.p12

Then copy the PKCS #12 file to the clone machine to be used in the clone instance configuration. For more details, see Section 2.7.6, “Cloning and Key Stores”.

Note

Keys cannot be exported from an HSM. However, in a typical deployment, HSMs support networked access, as long as the clone instance is installed using the same HSM as the master. If both instances use the same key store, then the keys are naturally available to the clone.

If backing up keys from the HSM is required, contact the HSM manufacturer for assistance.

10.2. Cloning a CA

Configure the master CA, and back up the keys.
In the CS.cfg file for the master CA, enable the master CA to monitor replication database changes by adding the ca.listenToCloneModifications parameter:
```
ca.listenToCloneModifications=true
```
Create the clone subsystem instance.
For examples of the configuration file required by pkispawn when cloning CA subsystems, see the Installing a CA clone and Installing a CA clone on the same host sections of the pkispawn(8) man page.
Restart the Directory Server instance used by the clone.
```
# systemctl restart pki-tomcatd@kra-clone-ds-instance.service
```
Note
Restarting the Directory Server reloads the updated schema, which is required for proper performance.

Restart the clone instance.

# systemctl restart pki-tomcatd@instance_name.service

After configuring the clone, test to make sure that the master-clone relationship is functioning:

Request a certificate from the cloned CA.
Approve the request.
Download the certificate to the browser.
Revoke the certificate.
Check master CA's CRL for the revoked certificate. In the master Certificate Manager's agent services page, click Update Certificate Revocation List. Find the CRL in the list.
The CRL should show the certificate revoked by the cloned Certificate Manager. If that certificate is not listed, check logs to resolve the problem.

10.3. Updating CA-KRA Connector Information After Cloning

As covered in Section 2.7.9, “Custom Configuration and Clones”, configuration information is not updated in clone instances if it is made after the clone is created. Likewise, changes made to a clone are not copied back to the master instance.

If a new KRA is installed or cloned after a clone CA is created, then the clone CA does not have the new KRA connector information in its configuration. This means that the clone CA is not able to send any archival requests to the KRA.

Whenever a new KRA is created or cloned, copy its connector information into all of the cloned CAs in the deployment. To do this, use the pki ca-kraconnector-add command.

If it is required to do this manually, follow these steps:

On the master clone machine, open the master CA's CS.cfg file, and copy all of the ca.connector.KRA.* lines for the new KRA connector.
```
[root@master ~]# vim /var/lib/pki/instance_name/ca/conf/CS.cfg
```

Stop the clone CA instance. For example:

[root@clone-ca ~]# systemctl stop pki-tomcatd@instance_name.service

Open the clone CA's CS.cfg file.

[root@clone-ca ~]# vim /var/lib/pki/instance_name/ca/conf/CS.cfg

Copy in the connector information for the new KRA instance or clone.

ca.connector.KRA.enable=true ca.connector.KRA.host=server-kra.example.com
ca.connector.KRA.local=false ca.connector.KRA.nickName=subsystemCert cert-pki-ca
ca.connector.KRA.port=10444 ca.connector.KRA.timeout=30
ca.connector.KRA.transportCert=MIIDbD...ZR0Y2zA==
ca.connector.KRA.uri=/kra/agent/kra/connector

Start the clone CA.

[root@clone-ca ~]# systemctl start pki-tomcatd@instance_name.service

10.4. Cloning OCSP Subsystems

Configure the master OCSP, and back up the keys.
In the CS.cfg file for the master OCSP, set the OCSP.Responder.store.defStore.refreshInSec parameter to any non-zero number other than 21600; 21600 is the setting for a clone.
```
# vim /etc/instance_name/CS.cfg

OCSP.Responder.store.defStore.refreshInSec=15000
```
Create the clone subsystem instance using the pkispawn utility.
For examples of the configuration file required by pkispawn when cloning OCSP subsystems, see the pkispawn(8) man page.
Restart the Directory Server instance used by the clone.
```
# systemctl dirsrv@instance_name.service
```
Note
Restarting the Directory Server reloads the updated schema, which is required for proper performance.

Restart the clone instance.

# systemctl restart pki-tomcatd@instance_name.service

After configuring the clone, test to make sure that the master-clone relationship is functioning:

Set up OCSP publishing in the master CA so that the CRL is published to the master OCSP.
Once the CRL is successfully published, check both the master and cloned OCSP's List Certificate Authorities link in the agent pages. The list should be identical.
Use the OCSPClient tool to submit OCSP requests to the master and the cloned Online Certificate Status Manager. The tool should receive identical OCSP responses from both managers.

10.5. Cloning KRA Subsystems

Configure the master subsystem, and back up the keys.
Create the clone subsystem instance using the pkispawn utility.
For examples of the configuration file required by pkispawn when cloning KRA subsystems, see the Installing a KRA or TPS clone section of the pkispawn(8) man page.
Restart the Directory Server instance used by the clone.
```
# systemctl dirsrv@instance_name.service
```
Note
Restarting the Directory Server reloads the updated schema, which is required for proper performance.

Restart the clone instance.

# systemctl restart pki-tomcatd@instance_name.service

For the KRA clone, test to make sure that the master-clone relationship is functioning:

Go to the KRA agent's page.
Click List Requests.
Select Show all requests for the request type and status.
Click Submit.
Compare the results from the cloned KRA and the master KRA. The results ought to be identical.

10.6. Cloning TKS Subsystems

Configure the master subsystem, and back up the keys.
Create the clone subsystem instance using the pkispawn utility.
For examples of the configuration file required by pkispawn when cloning TKS subsystems, see the Installing a KRA or TKS clone section of the pkispawn(8) man page.

Restart the clone instance.

# systemctl restart pki-tomcatd@instance_name.service

For the TKS, enroll a smart card and then run an ldapsearch to make sure that the same key information is contained in both databases.

10.7. Converting Masters and Clones

Only one single active CA generating CRLs can exist within the same topology. Similarly, only one OCSP receiving CRLs can exist within the same topology. As such, there can be any number of clones, but there can only be a single configured master for CA and OCSP.

For KRAs and TKSs, there is no configuration difference between masters and clones, but CAs and OCSPs do have some configuration differences. This means that when a master is taken offline — because of a failure or for maintenance or to change the function of the subsystem in the PKI — then the existing master must be reconfigured to be a clone, and one of the clones promoted to be the master.

10.7.1. Converting CA Clones and Masters

Stop the master CA if it is still running.
Open the existing master CA configuration directory:
```
# cd /var/lib/pki/instance_name/ca/conf
```
Edit the CS.cfg file for the master, and change the CRL and maintenance thread settings so that it is set as a clone:
- Disable control of the database maintenance thread:
```
ca.certStatusUpdateInterval=0
```
- Disable monitoring database replication changes:
```
ca.listenToCloneModifications=false
```
- Disable maintenance of the CRL cache:
```
ca.crl.IssuingPointId.enableCRLCache=false
```
- Disable CRL generation:
```
ca.crl.IssuingPointId.enableCRLUpdates=false
```
- Set the CA to redirect CRL requests to the new master:
```
master.ca.agent.host=new_master_hostname
master.ca.agent.port=new_master_port
```

Stop the cloned CA server.

# systemctl stop pki-tomcatd@instance_name.service

Open the cloned CA's configuration directory.
```
# cd /etc/instance_name
```
Edit the CS.cfg file to configure the clone as the new master.
1. Delete each line which begins with the ca.crl. prefix.
2. Copy each line beginning with the ca.crl. prefix from the former master CA CS.cfg file into the cloned CA's CS.cfg file.
3. Enable control of the database maintenance thread; the default value for a master CA is 600.
```
ca.certStatusUpdateInterval=600
```
4. Enable monitoring database replication:
```
ca.listenToCloneModifications=true
```
5. Enable maintenance of the CRL cache:
```
ca.crl.IssuingPointId.enableCRLCache=true
```
6. Enable CRL generation:
```
ca.crl.IssuingPointId.enableCRLUpdates=true
```
7. Disable the redirect settings for CRL generation requests:
```
master.ca.agent.host=hostname
master.ca.agent.port=port number
```

Start the new master CA server.

# systemctl start pki-tomcatd@instance_name.service

10.7.2. Converting OCSP Clones

Stop the OCSP master, if it is still running.
Open the existing master OCSP configuration directory.
```
# cd /etc/instance_name
```
Edit the CS.cfg, and reset the OCSP.Responder.store.defStore.refreshInSec parameter to 21600:
```
OCSP.Responder.store.defStore.refreshInSec=21600
```

Stop the online cloned OCSP server.

# systemctl stop pki-tomcatd@instance_name.service

Open the cloned OCSP responder's configuration directory.
```
# cd /etc/instance_name
```
Open the CS.cfg file, and delete the OCSP.Responder.store.defStore.refreshInSec parameter or change its value to any non-zero number:
```
OCSP.Responder.store.defStore.refreshInSec=15000
```

Start the new master OCSP responder server.

# systemctl start pki-tomcatd@instance_name.service

10.8. Cloning a CA That Has Been Re-Keyed

When a certificate expires, it has to be replaced. This can either be done by renewing the certificate, which re-uses the original keypair to generate a new certificate, or it can be done by generating a new keypair and certificate. The second method is called re-keying.

When a CA is re-keyed, new keypairs are stored in its certificate database, and these are the keys references for normal operations. However, for cloning a subsystem, the cloning process checks for the CA private key IDs as stored in its CS.cfg configuration file — and those key IDs are not updated when the certificate database keys change.

If a CA has been re-keyed and then an administrator attempts to clone it, the cloned CA fails to generate any certificates for the certificates which were re-keyed, and it shows up in the error logs with this error:

CertUtil::createSelfSignedCert() - CA private key is null!

To clone a CA that has been re-keyed:

Find all of the private key IDs in the CS.cfg file.

# grep privkey.id /var/lib/pki/instance_name/ca/conf/CS.cfg
cloning.signing.privkey.id     =-4d798441aa7230910d4e1c39fa132ea228d5d1bc
cloning.ocsp_signing.privkey.id =-3e23e743e0ddd88f2a7c6f69fa9f9bcebef1a60
cloning.subsystem.privkey.id     =-c3c1b3b4e8f5dd6d2bdefd07581c0b15529536
cloning.sslserver.privkey.id    =3023d30245804a4fab42be209ebb0dc683423a8f
cloning.audit_signing.privkey.id=2fe35d9d46b373efabe9ef01b8436667a70df096

Print all of the current private key IDs stored in the NSS database and compare them to the private key IDs stored in the CS.cfg file:

# certutil -K -d alias
certutil: Checking token "NSS Certificate DB" in slot "NSS User Private Key and Certificate Services"
Enter Password or Pin for "NSS Certificate DB":
< 0> rsa      a7b0944b7b8397729a4c8c9af3a9c2b96f49c6f3   caSigningCert cert-ca4-test-master
< 1> rsa      6006094af3e5d02aaa91426594ca66cb53e73ac0   ocspSigningCert cert-ca4-test-master
< 2> rsa      d684da39bf4f2789a3fc9d42204596f4578ad2d9   subsystemCert cert-ca4-test-master
< 3> rsa      a8edd7c2b5c94f13144cacd99624578ae30b7e43   sslserverCert cert-ca4-test1
< 4> rsa      2fe35d9d46b373efabe9ef01b8436667a70df096   auditSigningCert cert-ca4-test1

In this example, only the audit signing key is the same; the others have been changed.

Take the keys returned in step 2 and convert them from unsigned values (which is what certutil returns) to signed Java BigIntegers (which is how the keys are stored in the Certificate System database).
This can be done with a calculator or by using the script in Example 10.1, “Certutil to BigInteger Conversion Program”.

Copy the new key values into the CS.cfg file.

# vim /var/lib/pki/instance_name/ca/conf/CS.cfg

cloning.signing.privkey.id     =-584f6bb4847c688d65b373650c563d4690b6390d
cloning.ocsp_signing.privkey.id =6006094af3e5d02aaa91426594ca66cb53e73ac0
cloning.subsystem.privkey.id   =-297b25c640b0d8765c0362bddfba690ba8752d27
cloning.sslserver.privkey.id   =-5712283d4a36b0ecebb3532669dba8751cf481bd
cloning.audit_signing.privkey.id=2fe35d9d46b373efabe9ef01b8436667a70df096

Clone the CA as described in Section 10.2, “Cloning a CA”.

Example 10.1. Certutil to BigInteger Conversion Program

This Java program can convert the key output from certutil to the required BigInteger format.

Save this as a .java file, such as Test.java.

import java.math.BigInteger;

public class Test
{

  public static byte[] hexStringToByteArray(String s) {
      int len = s.length();
      byte[] data = new byte[len / 2];
      for (int i = 0; i < len; i += 2) {
          data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
                               + Character.digit(s.charAt(i+1), 16));
      }
      return data;
  }

  public static void main(String[] args)
  {
      byte[] bytes = hexStringToByteArray(args[0]);
      BigInteger big = new BigInteger (bytes);
      System.out.println("Result is  ==> " + big.toString(16));
  }
}

Then, compile the file:

# javac Test.java

Chapter 11. Additional Installation Options

All Red Hat Certificate System instances created with pkispawn make certain assumptions about the instances being installed, such as the default signing algorithm to use for CA signing certificates and whether to allow IPv6 addresses for hosts.

This chapter describes additional configuration options that impact the installation and configuration for new instances, so many of these procedures occur before the instance is created.

11.1. Lightweight Sub-CAs

Using the default settings, you are able to create lightweight sub-CAs. They enable you to configure services, like virtual private network (VPN) gateways, to accept only certificates issued by one sub-CA. At the same time, you can configure other services to accept only certificates issued by a different sub-CA or the root CA.

If you revoke the intermediate certificate of a sub-CA, all certificates issued by this sub-CA are automatically invalid.

If you set up the CA subsystem in Certificate System, it is automatically the root CA. All sub-CAs you create, are subordinated to this root CA.

11.1.1. Setting up a Lightweight Sub-CA

Depending on your environment, the installation of a sub-CA differs between Internal CAs and External CAs. For more information, see Section 7.8, “Setting up Subsystems with an External CA”.

11.1.2. Disabling the Creation of Lightweight Sub-CAs

In certain situations, administrators want to disable lightweight sub-CAs. To prevent adding, modifying, or removing sub-CAs, enter the following command on the Directory Server instance used by Certificate System:

# ldapmodify -D "cn=Directory Manager" -W -x -h server.example.com

dn: cn=aclResources,o=instance_name
changetype: modify
delete: resourceACLS
resourceACLS: certServer.ca.authorities:create,modify:allow (create,modify)
  group="Administrators":Administrators may create and modify lightweight authorities
delete: resourceACLS
resourceACLS: certServer.ca.authorities:delete:allow (delete)
  group="Administrators":Administrators may delete lightweight authorities

This command removes the default Access Control Lis