SAML2 Attribute Release

Attribute filtering and release policies are defined per SAML service. See this guide for more info.

Attribute Definitions

Attribute definitions that specifically apply to the release of attributes as part of SAML response can be defined using the SamlIdPAttributeDefinition. Defining an attribute with this definition does not prevent it from being released by other protocols.

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{
  "@class": "java.util.TreeMap",
  "eduPersonPrincipalName": {
    "@class": "org.apereo.cas.support.saml.web.idp.profile.builders.attr.SamlIdPAttributeDefinition",
    "key": "eduPersonPrincipalName",
    "name": "eduPersonPrincipalName",
    "urn": "urn:oid:1.3.6.1.4.1.5923.1.1.1.6",
    "scoped": true,
    "encrypted": false,
    "attribute": "uid",
    "friendlyName": "eduPersonPrincipalName"
  }
}

The following additional settings can be specified for a Saml IdP attribute definition:

Name Description
friendlyName (Optional) Friendly name of the attribute shared with the target application during attribute release.
urn (Optional) Defined Universal Resource name for an attribute (i.e. urn:oid:1.3.6.1.4.1.5923.1.1.1.6).

To learn more about attribute definitions, please see this guide.

Attribute Value Types

By default, attribute value blocks that are created in the final SAML2 response do not carry any type information in the encoded XML. You can, if necessary, enforce a particular type for an attribute value per the requirements of the SAML2 service provider, if any. An example of an attribute that is encoded with specific type information would be:

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<saml2:Attribute FriendlyName="givenName" Name="givenName" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri">
    <saml2:AttributeValue xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="xsd:string">HelloWorld</saml2:AttributeValue>
</saml2:Attribute>

The following attribute value types are supported:

Type Description
XSString Mark the attribute value type as string.
XSURI Mark the attribute value type as uri.
XSBoolean Mark the attribute value type as boolean.
XSInteger Mark the attribute value type as integer.
XSDateTime Mark the attribute value type as datetime .
XSBase64Binary Mark the attribute value type as base64Binary.
XSObject Skip the attribute value type and serialize the value as a complex XML object/POJO.

…where the types for each attribute would be defined as such:

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{
  "@class": "org.apereo.cas.support.saml.services.SamlRegisteredService",
  "serviceId" : "the-entity-id-of-the-sp",
  "name": "SAML Service",
  "metadataLocation" : "../../sp-metadata.xml",
  "id": 1,
  "attributeValueTypes": {
    "@class": "java.util.HashMap",
    "<attribute-name>": "<attribute-value-type>"
  }
}

Attribute Name Formats

Attribute name formats can be specified per relying party in the service registry.

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{
  "@class": "org.apereo.cas.support.saml.services.SamlRegisteredService",
  "serviceId" : "the-entity-id-of-the-sp",
  "name": "SAML Service",
  "metadataLocation" : "../../sp-metadata.xml",
  "id": 100001,
  "attributeNameFormats": {
    "@class": "java.util.HashMap",
    "attributeName": "basic|uri|unspecified|custom-format-etc"
  }
}

Name formats for an individual attribute can be mapped to a number of pre-defined formats, or a custom format of your own choosing. A given attribute that is to be encoded in the final SAML response may contain any of the following name formats:

Type Description
basic Map the attribute to urn:oasis:names:tc:SAML:2.0:attrname-format:basic.
uri Map the attribute to urn:oasis:names:tc:SAML:2.0:attrname-format:uri.
unspecified Map the attribute to urn:oasis:names:tc:SAML:2.0:attrname-format:basic.
urn:my:own:format Map the attribute to urn:my:own:format.

You may also have the option to define attributes and their relevant name format globally via CAS properties.

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. You should only include this field in your configuration if you need to modify the default value.

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.

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. The validation process is on by default and can be skipped on startup using a special system property SKIP_CONFIG_VALIDATION that should be set to true. 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.

Attribute Friendly Names

Attribute friendly names can be specified per relying party in the service registry, as well as globally via CAS settings. If there is no friendly name defined for the attribute, the attribute name will be used instead in its place. Note that the name of the attribute is one that is designed to be released to the service provider, specially if the original attribute is mapped to a different name.

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{
  "@class": "org.apereo.cas.support.saml.services.SamlRegisteredService",
  "serviceId" : "the-entity-id-of-the-sp",
  "name": "SAML Service",
  "metadataLocation" : "../../sp-metadata.xml",
  "id": 100001,
  "attributeFriendlyNames": {
    "@class": "java.util.HashMap",
    "urn:oid:2.5.4.42": "friendly-name-to-use"
  }
}

InCommon Research and Scholarship

A specific attribute release policy is available to release the attribute bundles needed for InCommon Research and Scholarship service providers using the entity attribute value http://id.incommon.org/category/research-and-scholarship:

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{
  "@class": "org.apereo.cas.support.saml.services.SamlRegisteredService",
  "serviceId": "entity-ids-allowed-via-regex",
  "name": "SAML",
  "id": 10,
  "metadataLocation": "path/to/incommon/metadata.xml",
  "attributeReleasePolicy": {
    "@class": "org.apereo.cas.services.ChainingAttributeReleasePolicy",
    "policies": [ "java.util.ArrayList",
      [
        {
          "@class": "org.apereo.cas.support.saml.services.InCommonRSAttributeReleasePolicy",
          "useUniformResourceName": false
        }
      ]
    ]
  }
}

Attributes authorized for release are set to be eduPersonPrincipalName, eduPersonTargetedID, email, displayName, givenName, surname, eduPersonScopedAffiliation.

REFEDS Research and Scholarship

A specific attribute release policy is available to release the attribute bundles needed for REFEDS Research and Scholarship service providers using the entity attribute value http://refeds.org/category/research-and-scholarship:

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{
  "@class": "org.apereo.cas.support.saml.services.SamlRegisteredService",
  "serviceId": "entity-ids-allowed-via-regex",
  "name": "SAML",
  "id": 10,
  "metadataLocation": "path/to/incommon/metadata.xml",
  "attributeReleasePolicy": {
    "@class": "org.apereo.cas.services.ChainingAttributeReleasePolicy",
    "policies": [ "java.util.ArrayList",
      [
         {"@class": "org.apereo.cas.support.saml.services.RefedsRSAttributeReleasePolicy"}
      ]
    ]
  }
}

This policy is an extension of InCommonRSAttributeReleasePolicy that operates based on different entity attribute value.

Releasing eduPersonTargetedID

If you do not have pre-calculated values for the eduPersonTargetedID attribute to fetch before release, you can let CAS calculate the eduPersonTargetedID attribute dynamically at release time using the following policy:

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{
  "@class": "org.apereo.cas.support.saml.services.SamlRegisteredService",
  "serviceId": "entity-ids-allowed-via-regex",
  "name": "SAML",
  "id": 10,
  "metadataLocation": "path/to/metadata.xml",
  "attributeReleasePolicy": {
    "@class": "org.apereo.cas.support.saml.services.EduPersonTargetedIdAttributeReleasePolicy",
    "salt": "OqmG80fEKBQt",
    "attribute": ""
  }
}

The generated id may be based off of an existing principal attribute. If left unspecified or attribute not found, the authenticated principal id is used.

Groovy Script

This policy allows a Groovy script to calculate the collection of released attributes.

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{
  "@class": "org.apereo.cas.support.saml.services.SamlRegisteredService",
  "serviceId": "entity-ids-allowed-via-regex",
  "name": "SAML",
  "id": 10,
  "metadataLocation": "path/to/incommon/metadata.xml",
  "attributeReleasePolicy": {
    "@class": "org.apereo.cas.support.saml.services.GroovySamlRegisteredServiceAttributeReleasePolicy",
    "groovyScript": "file:/etc/cas/config/script.groovy"
  }
}

The configuration of this component qualifies to use the Spring Expression Language syntax.

The outline of the script may be designed as:

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import java.util.*
import org.apereo.cas.support.saml.services.*
import org.apereo.cas.support.saml.*

Map<String, Object> run(final Object... args) {
    def attributes = args[0]
    def service = args[1]
    def resolver = args[2]
    def facade = args[3]
    def entityDescriptor = args[4]
    def applicationContext = args[5]
    def logger = args[6]
    ...
    return null;
}

The following parameters are passed to the script:

Parameter Description
attributes Map of current attributes resolved and available for release.
service The SAML service definition matched in the service registry.
resolver The metadata resolver instance of this service provider.
facade A wrapper on top of the metadata resolver that allows access to utility functions.
entityDescriptor The EntityDescriptor object matched and linked to this service provider’s metadata.
applicationContext CAS application context allowing direct access to beans, etc.
logger The object responsible for issuing log messages such as logger.info(...).

An example script follows:

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import java.util.*
import org.apereo.cas.support.saml.services.*
import org.apereo.cas.support.saml.*

def Map<String, Object> run(final Object... args) {
    def attributes = args[0]
    def service = args[1]
    def resolver = args[2]
    def facade = args[3]
    def entityDescriptor = args[4]
    def applicationContext = args[5]
    def logger = args[6]

    if (entityDescriptor.entityId == "TestingSAMLApplication") {
      return [username:["something"], another:"attribute"]
    }
    return [:]
}

Pattern Matching Entity Ids

In the event that an aggregate is defined containing multiple entity ids, the below attribute release policy may be used to release a collection of allowed attributes to entity ids grouped together by a regular expression pattern:

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{
  "@class": "org.apereo.cas.support.saml.services.SamlRegisteredService",
  "serviceId": "entity-ids-allowed-via-regex",
  "name": "SAML",
  "id": 10,
  "metadataLocation": "path/to/incommon/metadata.xml",
  "attributeReleasePolicy": {
    "@class": "org.apereo.cas.support.saml.services.PatternMatchingEntityIdAttributeReleasePolicy",
    "allowedAttributes" : [ "java.util.ArrayList", [ "cn", "mail", "sn" ] ],
    "fullMatch" : "true",
    "reverseMatch" : "false",
    "entityIds" : "entityId1|entityId2|somewhere.+"
  }
}

Entity Attributes Filter

This attribute release policy authorizes the release of defined attributes, provided the accompanying metadata for the service provider contains attributes that match certain values.

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{
  "@class": "org.apereo.cas.support.saml.services.SamlRegisteredService",
  "serviceId": "entity-ids-allowed-via-regex",
  "name": "SAML",
  "id": 10,
  "metadataLocation": "path/to/metadata.xml",
  "attributeReleasePolicy": {
    "@class": "org.apereo.cas.support.saml.services.MetadataEntityAttributesAttributeReleasePolicy",
    "allowedAttributes" : [ "java.util.ArrayList", [ "cn", "mail", "sn" ] ],
    "entityAttributeValues" : [ "java.util.LinkedHashSet", [ "entity-attribute-value" ] ],
    "entityAttribute" : "http://somewhere.org/category-x",
    "entityAttributeFormat" : "urn:oasis:names:tc:SAML:2.0:attrname-format:unspecified"
  }
}

The specification of entityAttributeFormat is optional.

Metadata Requested Attributes

This attribute release policy authorizes the release of defined attributes, based on the accompanying metadata for the service provider having requested attributes as part of its AttributeConsumingService element.

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{
  "@class": "org.apereo.cas.support.saml.services.SamlRegisteredService",
  "serviceId": "entity-ids-allowed-via-regex",
  "name": "SAML",
  "id": 10,
  "metadataLocation": "path/to/metadata.xml",
  "attributeReleasePolicy": {
    "@class": "org.apereo.cas.support.saml.services.MetadataRequestedAttributesAttributeReleasePolicy",
    "useFriendlyName" : false
  }
}

The useFriendlyName allows the filter to compare the requested attribute’s friendly name with the resolved attribute.

Metadata Registration Authority

This attribute release policy authorizes the release of a subset of attributes if the registration authority specified as a metadata extension produces a successful match.

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{
  "@class": "org.apereo.cas.support.saml.services.SamlRegisteredService",
  "serviceId": "entity-ids-allowed-via-regex",
  "name": "SAML",
  "id": 10,
  "metadataLocation": "path/to/metadata.xml",
  "attributeReleasePolicy": {
    "@class": "org.apereo.cas.support.saml.services.MetadataRegistrationAuthorityAttributeReleasePolicy",
    "registrationAuthority" : "urn:example:.*",
    "allowedAttributes" : [ "java.util.ArrayList", [ "cn", "mail", "sn" ] ]
  }
}

The registrationAuthority is a regular expression that is matched against the registration authority of the RegistrationInfo element to authorize release of allowed attributes.

Authentication Request Requested Attributes Filter

This attribute release policy authorizes the release of a subset of attributes requested as extensions of the SAML2 authentication request. The intersection of requested attributes and those allowed by the attribute release policy explicitly is evaluated for the final attribute release phase:

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{
  "@class": "org.apereo.cas.support.saml.services.SamlRegisteredService",
  "serviceId": "entity-ids-allowed-via-regex",
  "name": "SAML",
  "id": 10,
  "metadataLocation": "path/to/metadata.xml",
  "attributeReleasePolicy": {
    "@class": "org.apereo.cas.support.saml.services.AuthnRequestRequestedAttributesAttributeReleasePolicy",
    "useFriendlyName" : false
  }
}

The useFriendlyName allows the filter to compare the requested attribute’s friendly name with the resolved attribute.