Chapter 9. Policy enforcers

The policy enforcer configuration uses a JSON format and most of the time you don’t need to set anything if you want to automatically resolve the protected paths based on the resources available from your resource server.

If you want to manually define the resources being protected, you can use a slightly more verbose format:

{
  "enforcement-mode" : "ENFORCING",
  "paths": [
    {
      "path" : "/users/*",
      "methods" : [
        {
          "method": "GET",
          "scopes" : ["urn:app.com:scopes:view"]
        },
        {
          "method": "POST",
          "scopes" : ["urn:app.com:scopes:create"]
        }
      ]
    }
  ]
}

The following is a description of each configuration option:

A Claim Information Point (CIP) is responsible for resolving claims and pushing these claims to the Red Hat build of Keycloak server in order to provide more information about the access context to policies. They can be defined as a configuration option to the policy-enforcer in order to resolve claims from different sources, such as:

When pushing claims to the Red Hat build of Keycloak server, policies can base decisions not only on who a user is but also by taking context and contents into account, based on who, what, why, when, where, and which for a given transaction. It is all about Contextual-based Authorization and how to use runtime information in order to support fine-grained authorization decisions.

{
  "paths": [
    {
      "path": "/protected/resource",
      "claim-information-point": {
        "claims": {
          "claim-from-request-parameter": "{request.parameter['a']}",
          "claim-from-header": "{request.header['b']}",
          "claim-from-cookie": "{request.cookie['c']}",
          "claim-from-remoteAddr": "{request.remoteAddr}",
          "claim-from-method": "{request.method}",
          "claim-from-uri": "{request.uri}",
          "claim-from-relativePath": "{request.relativePath}",
          "claim-from-secure": "{request.secure}",
          "claim-from-json-body-object": "{request.body['/a/b/c']}",
          "claim-from-json-body-array": "{request.body['/d/1']}",
          "claim-from-body": "{request.body}",
          "claim-from-static-value": "static value",
          "claim-from-multiple-static-value": ["static", "value"],
          "param-replace-multiple-placeholder": "Test {keycloak.access_token['/custom_claim/0']} and {request.parameter['a']}"
        }
      }
    }
  ]
}

{
  "paths": [
    {
      "path": "/protected/resource",
      "claim-information-point": {
        "http": {
          "claims": {
            "claim-a": "/a",
            "claim-d": "/d",
            "claim-d0": "/d/0",
            "claim-d-all": [
              "/d/0",
              "/d/1"
            ]
          },
          "url": "http://mycompany/claim-provider",
          "method": "POST",
          "headers": {
            "Content-Type": "application/x-www-form-urlencoded",
            "header-b": [
              "header-b-value1",
              "header-b-value2"
            ],
            "Authorization": "Bearer {keycloak.access_token}"
          },
          "parameters": {
            "param-a": [
              "param-a-value1",
              "param-a-value2"
            ],
            "param-subject": "{keycloak.access_token['/sub']}",
            "param-user-name": "{keycloak.access_token['/preferred_username']}",
            "param-other-claims": "{keycloak.access_token['/custom_claim']}"
          }
        }
      }
    }
  ]
}

{
  "paths": [
    {
      "path": "/protected/resource",
      "claim-information-point": {
        "claims": {
          "claim-from-static-value": "static value",
          "claim-from-multiple-static-value": ["static", "value"]
        }
      }
    }
  ]
}

public class MyClaimInformationPointProviderFactory implements ClaimInformationPointProviderFactory<MyClaimInformationPointProvider> {

    @Override
    public String getName() {
        return "my-claims";
    }

    @Override
    public void init(PolicyEnforcer policyEnforcer) {

    }

    @Override
    public MyClaimInformationPointProvider create(Map<String, Object> config) {
        return new MyClaimInformationPointProvider(config);
    }
}

public class MyClaimInformationPointProvider implements ClaimInformationPointProvider {

    private final Map<String, Object> config;

    public MyClaimInformationPointProvider(Map<String, Object> config) {
        this.config = config;
    }

    @Override
    public Map<String, List<String>> resolve(HttpFacade httpFacade) {
        Map<String, List<String>> claims = new HashMap<>();

        // put whatever claim you want into the map

        return claims;
    }
}

When policy enforcement is enabled, the permissions obtained from the server are available through org.keycloak.AuthorizationContext. This class provides several methods you can use to obtain permissions and ascertain whether a permission was granted for a particular resource or scope.

Obtaining the Authorization Context in a Servlet Container

    HttpServletRequest request = // obtain javax.servlet.http.HttpServletRequest
    AuthorizationContext authzContext = (AuthorizationContext) request.getAttribute(AuthorizationContext.class.getName());

if (authzContext.hasResourcePermission("Project Resource")) {
    // user can access the Project Resource
}

if (authzContext.hasResourcePermission("Admin Resource")) {
    // user can access administration resources
}

if (authzContext.hasScopePermission("urn:project.com:project:create")) {
    // user can create new projects
}

The AuthorizationContext represents one of the main capabilities of Red Hat build of Keycloak Authorization Services. From the examples above, you can see that the protected resource is not directly associated with the policies that govern them.

Consider some similar code using role-based access control (RBAC):

if (User.hasRole('user')) {
    // user can access the Project Resource
}

if (User.hasRole('admin')) {
    // user can access administration resources
}

if (User.hasRole('project-manager')) {
    // user can create new projects
}

Although both examples address the same requirements, they do so in different ways. In RBAC, roles only implicitly define access for their resources. With Red Hat build of Keycloak, you gain the capability to create more manageable code that focuses directly on your resources whether you are using RBAC, attribute-based access control (ABAC), or any other BAC variant. Either you have the permission for a given resource or scope, or you do not have that permission.

Now, suppose your security requirements have changed and in addition to project managers, PMOs can also create new projects.

Security requirements change, but with Red Hat build of Keycloak there is no need to change your application code to address the new requirements. Once your application is based on the resource and scope identifier, you need only change the configuration of the permissions or policies associated with a particular resource in the authorization server. In this case, the permissions and policies associated with the Project Resource and/or the scope urn:project.com:project:create would be changed.

The AuthorizationContext can also be used to obtain a reference to the Authorization Client API configured to your application:

    ClientAuthorizationContext clientContext = ClientAuthorizationContext.class.cast(authzContext);
    AuthzClient authzClient = clientContext.getClient();

In some cases, resource servers protected by the policy enforcer need to access the APIs provided by the authorization server. With an AuthzClient instance in hands, resource servers can interact with the server in order to create resources or check for specific permissions programmatically.

The Red Hat build of Keycloak Server comes with a JavaScript library you can use to interact with a resource server protected by a policy enforcer. This library is based on the Red Hat build of Keycloak JavaScript adapter, which can be integrated to allow your client to obtain permissions from a Red Hat build of Keycloak Server.

You can obtain this library from a running a Red Hat build of Keycloak Server instance by including the following script tag in your web page:

<script src="http://.../js/keycloak-authz.js"></script>

Next, you can create a KeycloakAuthorization instance as follows:

const keycloak = ... // obtain a Keycloak instance from keycloak.js library
const authorization = new KeycloakAuthorization(keycloak);

The keycloak-authz.js library provides two main features:

In both cases, the library allows you to easily interact with both resource server and Red Hat build of Keycloak Authorization Services to obtain tokens with permissions your client can use as bearer tokens to access the protected resources on a resource server.

HTTP/1.1 401 Unauthorized
WWW-Authenticate: UMA realm="${realm}",
    as_uri="https://${host}:${port}/realms/${realm}",
    ticket="016f84e8-f9b9-11e0-bd6f-0021cc6004de"

// prepare a authorization request with the permission ticket
const authorizationRequest = {};
authorizationRequest.ticket = ticket;

// send the authorization request, if successful retry the request
Identity.authorization.authorize(authorizationRequest).then(function (rpt) {
    // onGrant
}, function () {
    // onDeny
}, function () {
    // onError
});

authorization.entitlement('my-resource-server-id').then(function (rpt) {
    // onGrant callback function.
    // If authorization was successful you'll receive an RPT
    // with the necessary permissions to access the resource server
});

authorization.entitlement('my-resource-server', {
    "permissions": [
        {
            "id" : "Some Resource"
        }
    ]
}).then(function (rpt) {
    // onGrant
});

const rpt = authorization.rpt;

When the server is using HTTPS, ensure your policy enforcer is configured as follows:

{
  "truststore": "path_to_your_trust_store",
  "truststore-password": "trust_store_password"
}

The configuration above enables TLS/HTTPS to the Authorization Client, making possible to access a Red Hat build of Keycloak Server remotely using the HTTPS scheme.