DynamoDb - SAML2 Metadata Management

Metadata documents may also be stored in and fetched from an Amazon DynamoDb 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-dynamodb</artifactId>
    <version>${cas.version}</version>
</dependency>
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implementation "org.apereo.cas:cas-server-support-saml-idp-metadata-dynamodb:${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-dynamodb"
}
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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-idp-metadata-dynamodb"
}

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

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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 DynamoDb metadata resolver",
  "metadataLocation" : "dynamodb://"
}

CAS records the service provider entity identifier in the entityId attribute and queries it through the entityIdIndex global secondary index. Deployments that manage the table outside CAS must define both.

:information_source: Metadata Location

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

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

cas.authn.saml-idp.metadata.dynamo-db.credential-access-keyUse access-key provided by AWS to authenticate.
no default
RequiredSpEL

Use access-key provided by AWS to authenticate.

Type
String
Default
none
Defined by
DynamoDbSamlMetadataProperties
Supports
Spring Expression Language
cas.authn.saml-idp.metadata.dynamo-db.credential-secret-keyUse secret key provided by AWS to authenticate.
no default
RequiredSpEL

Use secret key provided by AWS to authenticate.

Type
String
Default
none
Defined by
DynamoDbSamlMetadataProperties
Supports
Spring Expression Language
cas.authn.saml-idp.metadata.dynamo-db.crypto.encryption.keyThe encryption key is a string whose length is defined by the encryption key size setting.
no default
RequiredSpEL

The encryption key is a string whose length is defined by the encryption key size setting.

Type
String
Default
none
Defined by
EncryptionJwtCryptoProperties
Supports
Spring Expression Language
cas.authn.saml-idp.metadata.dynamo-db.crypto.signing.keyThe signing key is a string whose length is defined by the signing key size setting.
no default
RequiredSpEL

The signing key is a string whose length is defined by the signing key size setting.

Type
String
Default
none
Defined by
SigningJwtCryptoProperties
Supports
Spring Expression Language
cas.authn.saml-idp.metadata.dynamo-db.dax.urlCluster url.
no default
Required

Cluster url. For example, dax://my-cluster.l6fzcv.dax-clusters.us-east-1.amazonaws.com.

Type
String
Default
none
Defined by
DynamoDbDaxProperties
cas.authn.saml-idp.metadata.dynamo-db.endpointAWS custom endpoint.
no default
Required

AWS custom endpoint.

Type
String
Default
none
Defined by
DynamoDbSamlMetadataProperties
cas.authn.saml-idp.metadata.dynamo-db.regionAWS region used.
no default
Required

AWS region used.

Type
String
Default
none
Defined by
DynamoDbSamlMetadataProperties
cas.authn.saml-idp.metadata.dynamo-db.billing-modeBilling mode specifies how you are charged for read and write throughput and how you manage capacity.
PROVISIONED
Billing mode specifies how you are charged for read and write throughput and how you manage capacity. Available values are as follows:
  • PROVISIONED: Provisioned mode means that you specify the number of reads and writes per second that you expect your application to use. Provisioned mode is a good option if any of the following are true:
    • You have predictable application traffic.
    • You run applications whose traffic is consistent or ramps gradually.
    • You can forecast capacity requirements to control costs.
    You can use auto scaling to automatically adjust capacity based on the specified utilization rate to ensure application performance while reducing costs.
  • PAY_PER_REQUEST: Pay-per-request or on-demand billing means that you're charged for only the read/write requests that you use. On-demand mode is a good option if any of the following are true:
    • You create new tables with unknown workloads.
    • You have unpredictable application traffic.
    • You prefer the ease of paying for only what you use.
    • Tables using on-demand mode support all DynamoDB features (such as encryption at rest, point-in-time recovery, global tables, and so on) with the exception of auto scaling, which is not applicable with this mode.
      Type
      AbstractDynamoDbProperties.BillingMode
      Default
      PROVISIONED
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.client-execution-timeoutClient execution timeout.
      10000
      Duration

      Client execution timeout.

      Type
      String
      Default
      10000
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.connection-timeoutConnection timeout.
      5000
      Duration

      Connection timeout.

      Type
      String
      Default
      5000
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.crypto.algThe signing/encryption algorithm to use.
      no default

      The signing/encryption algorithm to use.

      Type
      String
      Default
      none
      Defined by
      EncryptionJwtSigningJwtCryptographyProperties
      cas.authn.saml-idp.metadata.dynamo-db.crypto.enabledWhether crypto operations are enabled.
      true

      Whether crypto operations are enabled.

      Type
      Boolean
      Default
      true
      Defined by
      EncryptionJwtSigningJwtCryptographyProperties
      cas.authn.saml-idp.metadata.dynamo-db.crypto.encryption.key-sizeThe encryption key size.
      512

      The encryption key size.

      Type
      Integer
      Default
      512
      Defined by
      EncryptionJwtCryptoProperties
      cas.authn.saml-idp.metadata.dynamo-db.crypto.signing.key-sizeThe signing key size.
      512

      The signing key size.

      Type
      Integer
      Default
      512
      Defined by
      SigningJwtCryptoProperties
      cas.authn.saml-idp.metadata.dynamo-db.crypto.strategy-typeControl the cipher sequence of operations.
      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.
      Type
      String
      Default
      ENCRYPT_AND_SIGN
      Defined by
      EncryptionJwtSigningJwtCryptographyProperties
      cas.authn.saml-idp.metadata.dynamo-db.dax.connect-timeoutConnection timeout, calculated in milliseconds.
      PT5S
      Duration

      Connection timeout, calculated in milliseconds.

      Type
      String
      Default
      PT5S
      Defined by
      DynamoDbDaxProperties
      cas.authn.saml-idp.metadata.dynamo-db.dax.connection-ttlHow long should connections be kept alive, calculated in milliseconds.
      PT0S
      Duration

      How long should connections be kept alive, calculated in milliseconds.

      Type
      String
      Default
      PT0S
      Defined by
      DynamoDbDaxProperties
      cas.authn.saml-idp.metadata.dynamo-db.dax.idle-timeoutConnection idle timeout, calculated in milliseconds.
      PT15S
      Duration

      Connection idle timeout, calculated in milliseconds.

      Type
      String
      Default
      PT15S
      Defined by
      DynamoDbDaxProperties
      cas.authn.saml-idp.metadata.dynamo-db.dax.max-concurrencyDetermines the maximum number of concurrent requests that can be made to the DAX cluster.
      1000

      Determines the maximum number of concurrent requests that can be made to the DAX cluster.

      Type
      Integer
      Default
      1000
      Defined by
      DynamoDbDaxProperties
      cas.authn.saml-idp.metadata.dynamo-db.dax.read-retriesNumber of read retry attempts.
      2

      Number of read retry attempts.

      Type
      Integer
      Default
      2
      Defined by
      DynamoDbDaxProperties
      cas.authn.saml-idp.metadata.dynamo-db.dax.request-timeoutRequest execution timeout, calculated in milliseconds.
      PT5S
      Duration

      Request execution timeout, calculated in milliseconds.

      Type
      String
      Default
      PT5S
      Defined by
      DynamoDbDaxProperties
      cas.authn.saml-idp.metadata.dynamo-db.dax.write-retriesNumber of write retry attempts.
      2

      Number of write retry attempts.

      Type
      Integer
      Default
      2
      Defined by
      DynamoDbDaxProperties
      cas.authn.saml-idp.metadata.dynamo-db.drop-tables-on-startupFlag that indicates whether to drop tables on start up.
      false

      Flag that indicates whether to drop tables on start up.

      Type
      Boolean
      Default
      false
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.idp-metadata-table-nameThe table name used and created by CAS to hold saml idp metadata in DynamoDb.
      no default

      The table name used and created by CAS to hold saml idp metadata in DynamoDb. By default, leaving this setting blank will prevent CAS from storing or loading SAML idp metadata from DynamoDb. Example: DynamoDbCasSamlIdPMetadata

      Type
      String
      Default
      none
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.local-addressLocal address.
      no default

      Local address.

      Type
      String
      Default
      none
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.local-instanceIndicates that the database instance is local to the deployment that does not require or use any credentials or other configuration other than host and region.
      false

      Indicates that the database instance is local to the deployment that does not require or use any credentials or other configuration other than host and region. This is mostly used during development and testing.

      Type
      Boolean
      Default
      false
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.max-connectionsMaximum connections setting.
      10

      Maximum connections setting.

      Type
      Integer
      Default
      10
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.prevent-table-creation-on-startupFlag that indicates whether to prevent CAS from creating tables.
      false

      Flag that indicates whether to prevent CAS from creating tables.

      Type
      Boolean
      Default
      false
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.profile-nameProfile name to use.
      no default

      Profile name to use.

      Type
      String
      Default
      none
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.profile-pathProfile path.
      no default

      Profile path.

      Type
      String
      Default
      none
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.proxy-hostOptionally specifies the proxy host to connect through.
      no default

      Optionally specifies the proxy host to connect through.

      Type
      String
      Default
      none
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.proxy-passwordOptionally specifies the proxy password to connect through.
      no default

      Optionally specifies the proxy password to connect through.

      Type
      String
      Default
      none
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.proxy-usernameOptionally specifies the proxy username to connect through.
      no default

      Optionally specifies the proxy username to connect through.

      Type
      String
      Default
      none
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.read-capacityRead capacity.
      10

      Read capacity.

      Type
      Long
      Default
      10
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.retry-modeOutline the requested retry mode.
      STANDARD

      Outline the requested retry mode. Accepted values are STANDARD, LEGACY.

      Type
      String
      Default
      STANDARD
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.socket-timeoutSocket timeout.
      5000
      Duration

      Socket timeout.

      Type
      String
      Default
      5000
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.table-nameThe table name used and created by CAS to hold SAML service provider metadata in DynamoDb.
      DynamoDbCasSamlMetadata

      The table name used and created by CAS to hold SAML service provider metadata in DynamoDb.

      Type
      String
      Default
      DynamoDbCasSamlMetadata
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.time-offsetTime offset.
      0

      Time offset.

      Type
      Integer
      Default
      0
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.use-reaperFlag that indicates whether to use reaper.
      false

      Flag that indicates whether to use reaper.

      Type
      Boolean
      Default
      false
      Defined by
      DynamoDbSamlMetadataProperties
      cas.authn.saml-idp.metadata.dynamo-db.write-capacityWrite capacity.
      10

      Write capacity.

      Type
      Long
      Default
      10
      Defined by
      DynamoDbSamlMetadataProperties

      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.

      Signing & encryption

      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.


      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.

      :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, 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.

      Actuator Endpoints

      The following endpoints are provided by CAS:

      samlIdPRegisteredServiceMetadata
      CAS endpoint4 operationsNot exposed by default
      1

      Turn the endpoint on and expose it over the web. One entry covers every operation. By default only info, health and status are exposed.

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      management.endpoint.samlIdPRegisteredServiceMetadata.access=UNRESTRICTED
      management.endpoints.web.exposure.include=samlIdPRegisteredServiceMetadata
      

      Endpoints may be mapped to other paths. For example, to serve health at healthcheck:

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      management.endpoints.web.path-mapping.health=healthcheck
      

      Identity Provider Metadata

      Metadata artifacts that belong to CAS as a SAML2 identity provider may also be managed and stored via Amazon DynamoDb. Artifacts such as the metadata, signing and encryption keys, etc are kept inside a bucket that carries a JSON document with the following fields:

      Field Description
      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).
      metadata The metadata document.

      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.