Amazon S3 - SAML2 Metadata Management

Metadata documents may also be stored in and fetched from an Amazon S3 instance. 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 in and fetched from a single pre-defined bucket that is taught to CAS via settings.

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-aws-s3</artifactId>
    <version>${cas.version}</version>
</dependency>
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implementation "org.apereo.cas:cas-server-support-saml-idp-metadata-aws-s3:${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-aws-s3"
}
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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-aws-s3"
}

SAML service definitions must then be designed as follows to allow CAS to fetch metadata documents from Amazon S3 buckets:

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{
  "@class" : "org.apereo.cas.support.saml.services.SamlRegisteredService",
  "serviceId" : "the-entity-id-of-the-sp(s)",
  "name" : "SAMLService",
  "id" : 10000003,
  "description" : "Amazon S3-based metadata resolver",
  "metadataLocation" : "awss3://"
}

The following parameters are expected for the Amazon S3 object metadata:

Parameter Description
signature The metadata signing certificate, if any.
:information_source: Metadata Location

The metadata location in the registration record above needs to be specified as awss3:// to signal to CAS that SAML metadata for registered service provider must be fetched from Amazon S3 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.amazon-s3.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.amazon-s3.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.amazon-s3.credential-access-key=
  • Use access-key provided by AWS to authenticate.

    This setting supports the Spring Expression Language.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.AmazonS3SamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.amazon-s3.credential-secret-key=
  • Use secret key provided by AWS to authenticate.

    This setting supports the Spring Expression Language.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.AmazonS3SamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.amazon-s3.endpoint=
  • AWS custom endpoint.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.AmazonS3SamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.amazon-s3.region=
  • AWS region used.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.AmazonS3SamlMetadataProperties.

    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.amazon-s3.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.amazon-s3.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.amazon-s3.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.amazon-s3.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.amazon-s3.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.amazon-s3.bucket-name=
  • S3 bucket that contains metadata files.

    This setting supports the Spring Expression Language.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.AmazonS3SamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.amazon-s3.client-execution-timeout=10000
  • Client execution timeout.

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

    org.apereo.cas.configuration.model.support.saml.idp.metadata.AmazonS3SamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.amazon-s3.connection-timeout=5000
  • Connection timeout.

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

    org.apereo.cas.configuration.model.support.saml.idp.metadata.AmazonS3SamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.amazon-s3.idp-metadata-bucket-name=
  • The collection name that is responsible to hold the identity provider metadata.

    This setting supports the Spring Expression Language.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.AmazonS3SamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.amazon-s3.local-address=
  • Local address.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.AmazonS3SamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.amazon-s3.max-connections=10
  • Maximum connections setting.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.AmazonS3SamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.amazon-s3.profile-name=
  • Profile name to use.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.AmazonS3SamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.amazon-s3.profile-path=
  • Profile path.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.AmazonS3SamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.amazon-s3.proxy-host=
  • Optionally specifies the proxy host to connect through.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.AmazonS3SamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.amazon-s3.proxy-password=
  • Optionally specifies the proxy password to connect through.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.AmazonS3SamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.amazon-s3.proxy-username=
  • Optionally specifies the proxy username to connect through.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.AmazonS3SamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.amazon-s3.retry-mode=STANDARD
  • Outline the requested retry mode. Accepted values are STANDARD, LEGACY.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.AmazonS3SamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.amazon-s3.socket-timeout=5000
  • Socket timeout.

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

    org.apereo.cas.configuration.model.support.saml.idp.metadata.AmazonS3SamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.amazon-s3.use-reaper=false
  • Flag that indicates whether to use reaper.

    org.apereo.cas.configuration.model.support.saml.idp.metadata.AmazonS3SamlMetadataProperties.

    How can I configure this property?

  • cas.authn.saml-idp.metadata.amazon-s3.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.amazon-s3.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.amazon-s3.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.amazon-s3.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.amazon-s3.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.amazon-s3.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.amazon-s3.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.

    Identity Provider Metadata

    Metadata artifacts that belong to CAS as a SAML2 identity provider may also be managed and stored via Amazon S3 buckets. Artifacts such as the metadata, signing and encryption keys, etc are kept inside a bucket with metadata that would have the following structure:

    Field Description
    id The identifier of the record.
    signingCertificate The signing certificate.
    signingKey The signing key.
    encryptionCertificate The encryption certificate.
    encryptionKey The encryption key.
    appliesTo The owner of this metadata document (i.e. CAS).

    The actual object’s content/body is expected to contain the SAML2 identity provider metadata. Note that the signing and encryption keys are expected to be encrypted and signed using CAS crypto keys.

    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 be put in a special bucket named using the [service-name][service-numeric-identifier] format.