Git - SAML2 Metadata Management

Metadata documents may also be stored in and fetched from Git repositories. This may specially be used to avoid copying metadata files across CAS nodes in a cluster, particularly where one needs to deal with more than a few bilateral SAML integrations. Metadata documents are stored as XML files, and their signing certificate, optionally, is expected to be found in a .pem file by the same name in the repository. (i.e. SP.xml’s certificate can be found in SP.pem).

Support is enabled by including the following module in the overlay:

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<dependency>
    <groupId>org.apereo.cas</groupId>
    <artifactId>cas-server-support-saml-idp-metadata-git</artifactId>
    <version>${cas.version}</version>
</dependency>
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implementation "org.apereo.cas:cas-server-support-saml-idp-metadata-git:${project.'cas.version'}"
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dependencyManagement {
    imports {
        mavenBom "org.apereo.cas:cas-server-support-bom:${project.'cas.version'}"
    }
}

dependencies {
    implementation "org.apereo.cas:cas-server-support-saml-idp-metadata-git"
}
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dependencies {
    /*
    The following platform references should be included automatically and are listed here 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-idp-metadata-git"
}

SAML service definitions must then be designed as follows to allow CAS to fetch metadata documents from Git repositories:

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{
  "@class" : "org.apereo.cas.support.saml.services.SamlRegisteredService",
  "serviceId" : "the-entity-id-of-the-sp",
  "name" : "SAMLService",
  "id" : 1,
  "description" : "A Git-based metadata resolver",
  "metadataLocation" : "git://"
}

Give the above definition, the expectation is that the git repository contains a SAMLService.xml file which may optionally also be accompanied by a SAMLService.pem file.

:information_source: Metadata Location

The metadata location in the registration record above needs to be specified as git:// to signal to CAS that SAML metadata for registered service provider must be fetched from Git repositories defined in CAS configuration.

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

The configuration settings listed below are tagged as Required in the CAS configuration metadata. This flag indicates that the presence of the setting may be needed to activate or affect the behavior of the CAS feature and generally should be reviewed, possibly owned and adjusted. If the setting is assigned a default value, you do not need to strictly put the setting in your copy of the configuration, but should review it nonetheless to make sure it matches your deployment expectations.

  • cas.authn.saml-idp.metadata.git.clone-directory.location=
  • The location of the resource. Resources can be URLs, or files found either on the classpath or outside somewhere in the file system.

    In the event the configured resource is a Groovy script, specially if the script set to reload on changes, you may need to adjust the total number of inotify instances. On Linux, you may need to add the following line to /etc/sysctl.conf: fs.inotify.max_user_instances = 256.

    You can check the current value via cat /proc/sys/fs/inotify/max_user_instances.

    In situations and scenarios where CAS is able to automatically watch the underlying resource for changes and detect updates and modifications dynamically, you may be able to specify the following setting as either an environment variable or system property with a value of false to disable the resource watcher: org.apereo.cas.util.io.PathWatcherService.

    org.apereo.cas.configuration.model.SpringResourceProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.crypto.encryption.key=
  • The encryption key is a JWT whose length is defined by the encryption key size setting.

    This setting supports the Spring Expression Language.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtCryptoProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.crypto.signing.key=
  • The signing key is a JWT whose length is defined by the signing key size setting.

    This setting supports the Spring Expression Language.

    org.apereo.cas.configuration.model.core.util.SigningJwtCryptoProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.private-key.location=
  • The location of the resource. Resources can be URLs, or files found either on the classpath or outside somewhere in the file system.

    In the event the configured resource is a Groovy script, specially if the script set to reload on changes, you may need to adjust the total number of inotify instances. On Linux, you may need to add the following line to /etc/sysctl.conf: fs.inotify.max_user_instances = 256.

    You can check the current value via cat /proc/sys/fs/inotify/max_user_instances.

    In situations and scenarios where CAS is able to automatically watch the underlying resource for changes and detect updates and modifications dynamically, you may be able to specify the following setting as either an environment variable or system property with a value of false to disable the resource watcher: org.apereo.cas.util.io.PathWatcherService.

    org.apereo.cas.configuration.model.SpringResourceProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.active-branch=master
  • The branch to checkout and activate, defaults to master.

    This setting supports the Spring Expression Language.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.GitSamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.branches-to-clone=*
  • If the repository is to be cloned, this will allow a select list of branches to be fetched. List the branch names separated by commas or use * to clone all branches. Defaults to all branches.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.GitSamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.repository-url=
  • The address of the git repository. Could be a URL or a file-system path.

    This setting supports the Spring Expression Language.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.GitSamlMetadataProperties.

    How can I configure this property?

    The configuration settings listed below are tagged as Optional in the CAS configuration metadata. This flag indicates that the presence of the setting is not immediately necessary in the end-user CAS configuration, because a default value is assigned or the activation of the feature is not conditionally controlled by the setting value. In other words, you should only include this field in your configuration if you need to modify the default value or if you need to turn on the feature controlled by the setting.

  • cas.authn.saml-idp.metadata.git.crypto.alg=
  • The signing/encryption algorithm to use.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtSigningJwtCryptographyProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.crypto.enabled=true
  • Whether crypto operations are enabled.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtSigningJwtCryptographyProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.crypto.encryption.key-size=512
  • The encryption key size.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtCryptoProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.crypto.signing.key-size=512
  • The signing key size.

    org.apereo.cas.configuration.model.core.util.SigningJwtCryptoProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.crypto.strategy-type=ENCRYPT_AND_SIGN
  • Control the cipher sequence of operations. The accepted values are:

    • ENCRYPT_AND_SIGN: Encrypt the value first, and then sign.
    • SIGN_AND_ENCRYPT: Sign the value first, and then encrypt.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtSigningJwtCryptographyProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.clear-existing-identities=false
  • When establishing an ssh session, determine if default identities loaded on the machine should be excluded/removed and identity should only be limited to those loaded from given keys.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.GitSamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.http-client-type=JDK
  • Implementation of HTTP client to use when doing git operations via http/https. The jgit library sets the connection factory statically (globally) so this property should be set to the same value for all git repositories (services, saml, etc). Not doing so might result in one connection factory being used for clone and another for subsequent fetches. Available values are as follows:

    • JDK: Built-in JDK http/https client.
    • HTTP_CLIENT: Apache HTTP Client http/https client.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.GitSamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.idp-metadata-enabled=false
  • Whether identity provider metadata artifacts are expected to be found in the database.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.GitSamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.password=
  • Password used to access or push to the repository.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.GitSamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.private-key-passphrase=
  • Password for the SSH private key.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.GitSamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.push-changes=false
  • Decide whether changes should be pushed back into the remote repository.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.GitSamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.rebase=false
  • Whether to rebase on pulls.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.GitSamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.sign-commits=false
  • Whether commits should be signed.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.GitSamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.ssh-session-password=
  • As with using SSH with public keys, an SSH session with ssh://user@example.com/repo.git must be specified to use password-secured SSH connections.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.GitSamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.strict-host-key-checking=true
  • Whether on not to turn on strict host key checking. true will be "yes", false will be "no", "ask" not supported.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.GitSamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.timeout=PT10S
  • Timeout for git operations such as push and pull in seconds.

    This settings supports the java.time.Duration syntax [?].

    org.apereo.cas.configuration.model.support.saml.idp.metadata.GitSamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.username=
  • Username used to access or push to the repository.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.GitSamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.crypto.encryption.key=
  • The encryption key is a JWT whose length is defined by the encryption key size setting.

    This setting supports the Spring Expression Language.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtCryptoProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.crypto.signing.key=
  • The signing key is a JWT whose length is defined by the signing key size setting.

    This setting supports the Spring Expression Language.

    org.apereo.cas.configuration.model.core.util.SigningJwtCryptoProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.crypto.alg=
  • The signing/encryption algorithm to use.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtSigningJwtCryptographyProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.crypto.enabled=true
  • Whether crypto operations are enabled.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtSigningJwtCryptographyProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.crypto.encryption.key-size=512
  • The encryption key size.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtCryptoProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.crypto.signing.key-size=512
  • The signing key size.

    org.apereo.cas.configuration.model.core.util.SigningJwtCryptoProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.crypto.strategy-type=ENCRYPT_AND_SIGN
  • Control the cipher sequence of operations. The accepted values are:

    • ENCRYPT_AND_SIGN: Encrypt the value first, and then sign.
    • SIGN_AND_ENCRYPT: Sign the value first, and then encrypt.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtSigningJwtCryptographyProperties.

    How can I configure this property?

    This CAS feature is able to accept signing and encryption crypto keys. In most scenarios if keys are not provided, CAS will auto-generate them. The following instructions apply if you wish to manually and beforehand create the signing and encryption keys.

    Note that if you are asked to create a JWK of a certain size for the key, you are to use the following set of commands to generate the token:

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    wget https://raw.githubusercontent.com/apereo/cas/master/etc/jwk-gen.jar
    java -jar jwk-gen.jar -t oct -s [size]
    

    The outcome would be similar to:

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    {
      "kty": "oct",
      "kid": "...",
      "k": "..."
    }
    

    The generated value for k needs to be assigned to the relevant CAS settings. Note that keys generated via the above algorithm are processed by CAS using the Advanced Encryption Standard (AES) algorithm which is a specification for the encryption of electronic data established by the U.S. National Institute of Standards and Technology.


    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.

    :information_source: 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, specially 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.

    Reloading Service Provider Metadata

    By default, SAML2 service provider metadata is pulled from git repositories when there is a need to resolve and fetch metadata. You could also configure CAS to activate and turn on a background job to pull metadata periodically using a background scheduler.

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

    The configuration settings listed below are tagged as Required in the CAS configuration metadata. This flag indicates that the presence of the setting may be needed to activate or affect the behavior of the CAS feature and generally should be reviewed, possibly owned and adjusted. If the setting is assigned a default value, you do not need to strictly put the setting in your copy of the configuration, but should review it nonetheless to make sure it matches your deployment expectations.

    The configuration settings listed below are tagged as Optional in the CAS configuration metadata. This flag indicates that the presence of the setting is not immediately necessary in the end-user CAS configuration, because a default value is assigned or the activation of the feature is not conditionally controlled by the setting value. In other words, you should only include this field in your configuration if you need to modify the default value or if you need to turn on the feature controlled by the setting.

  • cas.authn.saml-idp.metadata.git.schedule.enabled=true
  • Whether scheduler should be enabled to schedule the job to run.

    org.apereo.cas.configuration.model.support.quartz.SchedulingProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.schedule.enabled-on-host=.*
  • 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.

    This settings supports regular expression patterns. [?].

    org.apereo.cas.configuration.model.support.quartz.SchedulingProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.schedule.repeat-interval=PT2M
  • String representation of a repeat interval of re-loading data for a data store implementation. This is the timeout between consecutive job’s executions.

    This settings supports the java.time.Duration syntax [?].

    org.apereo.cas.configuration.model.support.quartz.SchedulingProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.git.schedule.start-delay=PT15S
  • 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

    This settings supports the java.time.Duration syntax [?].

    org.apereo.cas.configuration.model.support.quartz.SchedulingProperties.

    How can I configure this property?

    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.

    :information_source: 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, specially 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.

    Identity Provider Metadata

    Metadata artifacts that belong to CAS as a SAML2 identity provider may also be managed and stored via Git. Artifacts such as the metadata, signing and encryption keys, etc are kept on the file-system in distinct directory locations inside the repository and data is pushed to or pulled from git repositories on demand.

    Per Service

    Identity provider metadata, certificates and keys can also be defined on a per-service basis to override the global defaults. Metadata documents that would be applicable to a service definition need to adjust the appliesTo field in the metadata document, which is used to construct the directory path to metadata artifacts.