Overview

CAS can be integrated with the Shibboleth federated SSO platform by a couple different strategies. It is possible to designate CAS to serve as the authentication provider for the Shibboleth IdP. With such a setup, when user is routed to the IdP, the following may take place:

If the user has already authenticated to CAS and has a valid CAS SSO session, the IdP will transparently perform the requested action, e.g. attribute release.
If the user does not have a valid CAS SSO session, the user will be redirected to CAS and must authenticate before the IdP proceeds with the requested action.

Note

Remember that this page is specifically dedicated to integration options with the Shibboleth Identity Provider. If you need CAS to act as a SAML2 identity provider on its own, you should start here instead.

SSO for Shibboleth IdP (External)

This is a Shibboleth IdP external authentication plugin that delegates the authentication to CAS. This solution has the ability to utilize a full range of native CAS protocol features such as renew and gateway.

The plugin is available for both Shibboleth Identity Provider v2 and v3 and v4.

Support is enabled by including the following dependency in the WAR overlay:

<dependency>
    <groupId>org.apereo.cas</groupId>
    <artifactId>cas-server-support-shibboleth</artifactId>
    <version>${cas.version}</version>
</dependency>

implementation "org.apereo.cas:cas-server-support-shibboleth:${project.'cas.version'}"

dependencyManagement {
    imports {
        mavenBom "org.apereo.cas:cas-server-support-bom:${project.'cas.version'}"
    }
}

dependencies {
    implementation "org.apereo.cas:cas-server-support-shibboleth"
}

dependencies {
    /*
        The following platform references are included automatically and are listed for reference only.

        implementation enforcedPlatform("org.apereo.cas:cas-server-support-bom:${project.'cas.version'}")
        implementation platform(org.springframework.boot.gradle.plugin.SpringBootPlugin.BOM_COORDINATES)
        
    */
    implementation "org.apereo.cas:cas-server-support-shibboleth"
}

The following settings and properties are available from the CAS configuration catalog:

cas.authn.shib-idp.server-urlThe server url of the shibboleth idp deployment.

localhost

The server url of the shibboleth idp deployment.

Type: String
Default: localhost
Defined by: ShibbolethIdPProperties

Required settings may be needed to activate or affect the feature; review them even when they have a default. Optional settings only need to be set to change a default or to turn on the behavior they control. Third party settings belong to libraries such as Spring Boot that CAS builds on; their own documentation may have more detail.

Notes on configuration

Configuration Metadata

The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.

Be Selective

This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.

YAGNI

Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.

Naming Convention

Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those that might be presented to the system via an external library or framework such as Spring Boot, etc.

Note

When possible, properties should be stored in lower-case kebab format, such as cas.property-name=value. The only possible exception to this rule is when naming actuator endpoints; The name of the actuator endpoints (i.e. ssoSessions) MUST remain in camelCase mode.

Settings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the way you intend.

Validation

Configuration properties are automatically validated on CAS startup to report issues with configuration binding, especially if defined CAS settings cannot be recognized or validated by the configuration schema. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.

Indexed Settings

CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be incremented by the adopter to allow for distinct multiple configuration blocks.

Relying Party EntityId

The authentication plugin is able to pass the relying party’s entity ID over to the CAS server upon authentication requests. The entity ID is passed in form of a url parameter to the CAS server as such:

https://sso.example.org/cas/login?service=<authentication-plugin-url>&entityId=<relying-party-entity-id>

You can also take advantage of the entityId parameter and treat it as a normal CAS service definition, so it can be used for multifactor authentication and authorization.

See this guide for more info.

Displaying SAML MDUI

The CAS server is able to recognize the entityId parameter and display SAML MDUI on the login page, that is provided by the metadata associated with the relying party.

Configuration

Support is enabled by including the following dependency in the WAR overlay:

<dependency>
    <groupId>org.apereo.cas</groupId>
    <artifactId>cas-server-support-saml-mdui</artifactId>
    <version>${cas.version}</version>
</dependency>

implementation "org.apereo.cas:cas-server-support-saml-mdui:${project.'cas.version'}"

dependencyManagement {
    imports {
        mavenBom "org.apereo.cas:cas-server-support-bom:${project.'cas.version'}"
    }
}

dependencies {
    implementation "org.apereo.cas:cas-server-support-saml-mdui"
}

dependencies {
    /*
        The following platform references are included automatically and are listed for reference only.

        implementation enforcedPlatform("org.apereo.cas:cas-server-support-bom:${project.'cas.version'}")
        implementation platform(org.springframework.boot.gradle.plugin.SpringBootPlugin.BOM_COORDINATES)
        
    */
    implementation "org.apereo.cas:cas-server-support-saml-mdui"
}

The following settings and properties are available from the CAS configuration catalog:

cas.saml-metadata-ui.resourcesMetadata resources to load and parse through based on the incoming entity id in order to locate MDUI.

no default

Required

Metadata resources to load and parse through based on the incoming entity id in order to locate MDUI. Resources can be classpath/file/http resources. If each metadata resource has a signing certificate, they can be added onto the resource with a :: separator. Example: classpath:/sp-metadata.xml::classpath:/pub.key.

Type: List<String>
Default: none
Defined by: SamlMetadataUIProperties

cas.saml-metadata-ui.max-validityIf specified, creates a validity filter on the metadata to check for metadata freshness based on the max validity.

0

If specified, creates a validity filter on the metadata to check for metadata freshness based on the max validity. Value is specified in seconds.

Type: Long
Default: 0
Defined by: SamlMetadataUIProperties

cas.saml-metadata-ui.parameterThe parameter name that indicates the entity id of the service provider submitted to CAS.

entityId

The parameter name that indicates the entity id of the service provider submitted to CAS.

Type: String
Default: entityId
Defined by: SamlMetadataUIProperties

cas.saml-metadata-ui.require-signed-rootWhen parsing metadata, whether the root element is required to be signed.

false

When parsing metadata, whether the root element is required to be signed.

Type: Boolean
Default: false
Defined by: SamlMetadataUIProperties

cas.saml-metadata-ui.require-valid-metadataWhether valid metadata is required when parsing metadata.

true

Whether valid metadata is required when parsing metadata.

Type: Boolean
Default: true
Defined by: SamlMetadataUIProperties

cas.saml-metadata-ui.schedule.cron-expressionA cron-like expression, extending the usual UN*X definition to include triggers on the second, minute, hour, day of month, month, and day of week.

no default

A cron-like expression, extending the usual UN*X definition to include triggers on the second, minute, hour, day of month, month, and day of week. For example, 0 * * * * MON-FRI means once per minute on weekdays (at the top of the minute - the 0th second) or 0 0 0 * * * means every day at midnight. * Note that when cron expressions are defined, the start delay and repeat interval settings are must be removed and set to blank.

Type: String
Default: none
Defined by: SchedulingProperties

cas.saml-metadata-ui.schedule.cron-time-zoneA time zone for which the cron expression will be resolved.

no default

A time zone for which the cron expression will be resolved. By default, this attribute is empty (i.e. the scheduler's time zone will be used).

Type: String
Default: none
Defined by: SchedulingProperties

cas.saml-metadata-ui.schedule.enabledWhether scheduler should be enabled to schedule the job to run.

true

Whether scheduler should be enabled to schedule the job to run.

Type: Boolean
Default: true
Defined by: SchedulingProperties

cas.saml-metadata-ui.schedule.enabled-on-hostOverrides SchedulingProperties#enabled property value of true if this property does not match hostname of CAS server.

.*

Regex

Overrides SchedulingProperties#enabled property value of true if this property does not match hostname of CAS server. This can be useful if deploying CAS with an image in a statefulset where all names are predictable but where having different configurations for different servers is hard. The value can be an exact hostname or a regular expression that will be used to match the hostname.

Type: String
Default: .*
Defined by: SchedulingProperties

cas.saml-metadata-ui.schedule.repeat-intervalString representation of a repeat interval of re-loading data for a data store implementation.

PT2M

Duration

String representation of a repeat interval of re-loading data for a data store implementation. This is the timeout between consecutive job’s executions.

Type: String
Default: PT2M
Defined by: SchedulingProperties

cas.saml-metadata-ui.schedule.start-delayString representation of a start delay of loading data for a data store implementation.

PT15S

Duration

String representation of a start delay of loading data for a data store implementation. This is the delay between scheduler startup and first job’s execution

Type: String
Default: PT15S
Defined by: SchedulingProperties

Notes on configuration

Configuration Metadata

Be Selective

YAGNI

Naming Convention

Note

Validation

Indexed Settings

Relying Party Metadata

You may allow CAS to recognize SAML MDUI directly from metadata documents that are fed to CAS via settings. If the metadata for the relying party matches the requested entityId and contains MDUI elements, those will be passed onto the login page for decorations. If MDUI is not available in the metadata, the relevant elements from the matching service in the service registry will be used all the same.

Service Registry Metadata

You may also register the relying party in the CAS service registry as a regular service application and specify a number of MDUI-like elements in the body of the registration record. An example follows:

{
  "@class" : "org.apereo.cas.services.CasRegisteredService",
  "serviceId" : "relying-party-entity-id",
  "name" : "Test",
  "id" : 100,
  "description" : "This is the test application.",
  "evaluationOrder" : 10000,
  "logo": "images/logo.png",
  "informationUrl": "https://test.example.org/info",
  "privacyUrl": "https://test.example.org/privacy"
}