Chapter 4. Red Hat build of OpenJDK features

The latest Red Hat build of OpenJDK 21 release might include new features. Additionally, the latest release might enhance, deprecate, or remove features that originated from earlier Red Hat build of OpenJDK 21 releases.

Red Hat build of OpenJDK enhancements

Red Hat build of OpenJDK 21 provides enhancements to features originally created in earlier releases of Red Hat build of OpenJDK.

Warnings from jarsigner tool about removed file entries

In earlier Red Hat build of OpenJDK releases, when a file was removed from a signed JAR file but the file signature was still present, the jarsigner tool did not detect this situation.

In Red Hat build of OpenJDK 21.0.7, you can use the jarsigner ‑verify command to check that every signature has a matching file entry. If any mismatch exists, this command prints a warning. To display the names of any mismatched entries, add the ‑verbose option to the command.

See JDK-8309841 (JDK Bug System).

Distrust of TLS server certificates issued after 15 April 2025 and anchored by Camerfirma root CAs

In accordance with similar plans that Google, Mozilla, Apple, and Microsoft recently announced, Red Hat build of OpenJDK 21.0.7 distrusts TLS certificates that are issued after 15 April 2025 and anchored by Camerfirma root certificates.

Red Hat build of OpenJDK will continue to trust certificates that are issued on or before 15 April 2025 until these certificates expire.

If a server’s certificate chain is anchored by an affected certificate, any attempts to negotiate a TLS session now fail with an exception to indicate that the trust anchor is not trusted. For example:

TLS server certificate issued after 2025-04-15 and anchored by a distrusted legacy Camerfirma root CA: CN=Chambers of Commerce Root -
2008, O=AC Camerfirma S.A., SERIALNUMBER=A82743287, L=Madrid (see current address at www.camerfirma.com/address), C=EU

TLS server certificate issued after 2025-04-15 and anchored by a distrusted legacy Camerfirma root CA: CN=Chambers of Commerce Root -
2008, O=AC Camerfirma S.A., SERIALNUMBER=A82743287, L=Madrid (see current address at www.camerfirma.com/address), C=EU

You can check whether this change affects a certificate in a JDK keystore by using the following keytool command:

keytool -v -list -alias <your_server_alias> -keystore <your_keystore_filename>

If this change affects any certificate in the chain, update this certificate or contact the organisation that is responsible for managing the certificate.

If you want to continue using TLS server certificates that are anchored by Camerfirma root certificates, you can remove CAMERFIRMA_TLS from the jdk.security.caDistrustPolicies security property either by modifying the java.security configuration file or by using the java.security.properties system property.

These restrictions apply to the following Camerfirma root certificates that Red Hat build of OpenJDK includes:

See JDK-8346587 (JDK Bug System).

Fix for problematic SunPKCS11 provider checks on PKCS11 mechanism

In OpenJDK 14, the SunPKCS11 provider introduced the concept of legacy mechanisms. If a mechanism is using a weak algorithm, the provider determines that this mechanism is legacy and subsequently disables it.

In earlier releases, this behavior was inflexible. For example, you could not override the legacy determination to enable a disabled mechanism. Also, even if encryption was not being used, a mechanism that was being used for signing could be considered legacy and therefore disabled if it had a weak encryption algorithm. Similarly, a weak signing algorithm prevented use of the mechanism as a cipher for encryption or decryption.

Red Hat build of OpenJDK 21.0.7 resolves these issues by introducing the allowLegacy configuration property for the SunPKCS11 provider. You can override the legacy determination by setting the allowLegacy property to true. This property is set to false by default.

From this release onward, the provider also considers the service type when determining legacy status. The provider now checks encryption algorithms only for ciphers and checks signature algorithms only for signatures.

See JDK-8293345 (JDK Bug System).