Title:   Changes to SAML Specification for XACML-Compatible Authorization
Authors: Anne Anderson, Hal Lockhart, Simon Godik
Version: 1.4, 03/04/03 (yy/mm/dd)

Approved by XACML TC on 3 April 2003 for submitting to SSTC.

Description: This document contains recommended changes to
"Assertions and Protocol for the OASIS Security Assertion Markup
Language (SAML)" (OASIS Standard, 5 November 2002) to utilize the
XACML Request and Response Context formats for authorization
decisions.  The associated changes recommended to the SAML
Assertion and Protocol schemas that are appended to this
document.

These changes are being proposed for inclusion in SAML 2.0.

In order to distinguish SAML 2.0 XACML-Compatible elements from
the corresponding SAML 1.0 elements with the same name, the
recommended SAML 2.0 names are prefixed with "XC".  The SSTC
should change these names as appropriate.

The QName "xacml-context" refers to
"urn:oasis:names:tc:xacml:1.0:context", which is associated with
the schema "cs-xacml-schema-context-01.xsd" located in the OASIS
XACML TC Repository.  See
http://www.oasis-open.org/committees/xacml for links.

2.3.2 Element <XCAssertion>

Insert after line 403:

  <saml2:XCAuthorizationDecisionStatement>
      An authorization decision statement in the SAML 2.0 format,
      containing an authorization decision in a format compatible
      with the OASIS XACML Version 1.0 Standard.

Insert after line 416:
  <element ref="saml2:XCAuthorizationDecisionStatement"/>

2.3.2.2 Element <XCAdvice>

Replace line 533 with:

  <element name="XCAdvice" type="saml2:XCAdviceType"/>

Replace line 537 with:

  <element ref="saml2:XCAssertion"/>

2.4.4 Element <XCAuthorizationDecisionStatement>

Replace lines 738-795 (entire section) with:

  The <XCAuthorizationDecisionStatement> element supplies a
  statement by the issuer that the request for access by the
  specified subject or subjects to perform the specified action
  on the specified resource has resulted in the specified
  decision.  The decision is in the form of an
  xacml-context:Response.

  The <XCAuthorizationDecisionStatement> optionally contains a
  description of the context in which the decision was made, in
  the form of an xacml-context:Request.  This context may include
  only the information used in making the authorization decision,
  or may include additional information.  This is
  implementation-dependent.

  See OASIS eXtensible Access Control Markup Language (XACML)
  Version 1.0 for a description of the elements in an
  xacml-context:Response or xacml-context:Request.

  The <XCAuthorizationDecisionStatement> element is of type
  saml2:XCAuthorizationDecisionStatementType, which extends
  StatementAbstractType with the addition of the following
  elements (in order) and attributes:

  xacml-context:Response [Required]

     The decision rendered by the issuer with respect to an
     authorization decision query.  The value is of the
     xacml-context:Response type.

  xacml-context:Request [Optional]

     The information used to make the authorization decision.

     If the XCAuthorizationDecisionRequest "ReturnContext"
     attribute is TRUE, then this element MUST be supplied and
     MUST include all XACML Attributes used in making the
     authorization decision, whether supplied in the original
     XCAuthorizationDecisionQuery or obtained from external
     sources.  The xacml-context:Request MAY include additional
     XACML Attributes that were not used in making the
     authorization decision.

     If the XCAuthorizationDecisionRequest "ReturnContext"
     attribute is FALSE, then this element MUST NOT be supplied.

  The following schema fragment defines the
  <XCAuthorizationDecisionStatement> element and its
  XCAuthorizationDecisionStatementType complex type:

        <element name="XCAuthorizationDecisionStatement" type="saml2:XCAuthorizationDecisionStatementType"/>
        <complexType name="XCAuthorizationDecisionStatementType">
                <complexContent>
                        <extension base="saml:StatementAbstractType">
                                <sequence>
                                        <element ref="xacml-context:Response" />
                                        <element ref="xacml-context:Request" minOccurs="0"/>
                                </sequence>
                        </extension>
                </complexContent>
        </complexType>

2.4.4.2 Element <XCEvidence>

Replace line 819 with:

   <saml2:XCAssertion>

Replace line 830 with:
   
   <element ref="saml2:XCAssertion>

3.2.2 Element <XCRequest>

Insert after line 991:

  <saml2p:XCAuthorizationDecisionQuery>

     Makes a query for an authorization decision using the SAML
     2.0 format.

Insert after line 1006:

  <element ref="samlp2:XCAuthorizationDecisionQuery"/>

3.3.5 Element <XCAuthorizationDecisionQuery>

Replace lines 1110-1136 (entire section) with:

  The <samlp2:XCAuthorizationDecisionQuery> element is used to make
  the query "Should these actions on this resource be allowed for
  this subject or subjects?"  A successful response will be in
  the form of an assertion containing an
  XCAuthorizationDecisionStatement.  This element is of type
  XCAuthorizationDecisionQueryType, which extends QueryAbstractType
  with the addition of the following element and attributes:

  xacml-context:Request [Required]

     A description of the authorization request.  The value is of
     the xacml-context:Request type.

  InputContextOnly [Required]

     If this attribute is TRUE, the authorization decision MUST
     be made solely on the basis of information contained in the
     XCAuthorizationDecisionQuery; no external attributes are to be
     used.  If FALSE, the authorization decision MAY be made on
     the basis of external attributes not contained in the
     XCAuthorizationDecisionQuery.

  ReturnContext [Required]

     If this attribute is TRUE, the
     XCAuthorizationDecisionStatement returned MUST include the
     XACML Attributes used to make the authorization decision in
     the form of an xacml-context:Request; additional XACML
     Attributes MAY be included in the returned
     xacml-context:Request.  If this attribute is FALSE, the
     XCAuthorizationDecisionStatement returned MUST NOT include an
     xacml-context:Request.

  The following schema fragment defines the
  <XCAuthorizationDecisionQuery> element and its
  XCAuthorizationDecisionQueryType complex type:

        <element name="XCAuthorizationDecisionQuery" type="samlp2:XCAuthorizationDecisionQueryType"/>
        <complexType name="XCAuthorizationDecisionQueryType">
                <complexContent>
                        <extension base="samlp:QueryAbstractType">
                                <sequence>
                                        <element ref="xacml-context:Request" />
                                </sequence>
                                <attribute name="InputContextOnly" type="boolean" use="required"/>
                                <attribute name="ReturnContext" type="boolean" use="required"/>
                        </extension>
                </complexContent>
        </complexType>


3.4.2 Element <Response>

Replace line 1185 with:

  <saml2:XCAssertion> [Any Number] (see Section 2.3.2)

     Specifies an assertion by value.

Replace line 1194 with:

  <element ref="saml2:XCAssertion" minOccurs="0"

======================================================================================
SAML Assertion Schema Changes
======================================================================================
<?xml version="1.0" encoding="UTF-8"?>
<!-- edited with XML Spy v3.5 NT (http://www.xmlspy.com) by Phill Hallam-Baker (VeriSign Inc.) -->
<schema targetNamespace="urn:oasis:names:tc:SAML:2.0:assertion" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:saml="urn:oasis:names:tc:SAML:1.0:assertion" xmlns:saml2="urn:oasis:names:tc:SAML:2.0:assertion" xmlns:xacml-context="urn:oasis:names:tc:xacml:1.0:context" xmlns="http://www.w3.org/2001/XMLSchema" elementFormDefault="unqualified">
        <import namespace="http://www.w3.org/2000/09/xmldsig#" schemaLocation="http://www.w3.org/TR/xmldsig-core/xmldsig-core-schema.xsd"/>
        <import namespace="urn:oasis:names:tc:SAML:1.0:assertion" schemaLocation="http://www.oasis-open.org/committees/security/docs/oasis-sstc-saml-schema-assertion-1.0.xsd"/>
        <import namespace="urn:oasis:names:tc:xacml:1.0:context" schemaLocation="http://www.oasis-open.org/committees/xacml/repository/cs-xacml-schema-context-01.xsd"/>
        <annotation>
                <documentation>
                Document identifier: oasis-sstc-saml-schema-assertion-2.0
                Location: 
                </documentation>
        </annotation>
        <element name="XCAssertion" type="saml2:XCAssertionType"/>
        <complexType name="XCAssertionType">
                <sequence>
                        <element ref="saml:Conditions" minOccurs="0"/>
                        <element ref="saml2:XCAdvice" minOccurs="0"/>
                        <choice maxOccurs="unbounded">
                                <element ref="saml:Statement"/>
                                <element ref="saml:SubjectStatement"/>
                                <element ref="saml:AuthenticationStatement"/>
                                <element ref="saml:AuthorizationDecisionStatement"/>
                                <element ref="saml2:XCAuthorizationDecisionStatement"/>
                                <element ref="saml:AttributeStatement"/>
                        </choice>
                        <element ref="ds:Signature" minOccurs="0"/>
                </sequence>
                <attribute name="MajorVersion" type="integer" use="required"/>
                <attribute name="MinorVersion" type="integer" use="required"/>
                <attribute name="AssertionID" type="saml:IDType" use="required"/>
                <attribute name="Issuer" type="string" use="required"/>
                <attribute name="IssueInstant" type="dateTime" use="required"/>
        </complexType>
        <element name="XCAdvice" type="saml2:XCAdviceType"/>
        <complexType name="XCAdviceType">
                <choice minOccurs="0" maxOccurs="unbounded">
                        <element ref="saml:AssertionIDReference"/>
                        <element ref="saml2:XCAssertion"/>
                        <any namespace="##other" processContents="lax"/>
                </choice>
        </complexType>
        <element name="XCAuthorizationDecisionStatement" type="saml2:XCAuthorizationDecisionStatementType"/>
        <complexType name="XCAuthorizationDecisionStatementType">
                <complexContent>
                        <extension base="saml:StatementAbstractType">
                                <sequence>
                                        <element ref="xacml-context:Response" />
                                        <element ref="xacml-context:Request" minOccurs="0"/>
                                </sequence>
                        </extension>
                </complexContent>
        </complexType>
        <element name="XCEvidence" type="saml2:XCEvidenceType"/>
        <complexType name="XCEvidenceType">
                <choice maxOccurs="unbounded">
                        <element ref="saml:AssertionIDReference"/>
                        <element ref="saml2:XCAssertion"/>
                </choice>
        </complexType>
</schema>

======================================================================================
SAML Protocol Schema Changes
======================================================================================
<?xml version="1.0" encoding="UTF-8"?>
<!-- edited with XML Spy v4.2 U (http://www.xmlspy.com) by Phillip Hallam-Baker (Phillip Hallam-Baker) -->
<schema targetNamespace="urn:oasis:names:tc:SAML:2.0:protocol" xmlns:saml="urn:oasis:names:tc:SAML:1.0:assertion" xmlns:saml2="urn:oasis:names:tc:SAML:2.0:assertion" xmlns:samlp="urn:oasis:names:tc:SAML:1.0:protocol" xmlns:samlp2="urn:oasis:names:tc:SAML:2.0:protocol" xmlns:xacml-context="urn:oasis:names:tc:xacml:1.0:context" xmlns="http://www.w3.org/2001/XMLSchema" elementFormDefault="unqualified">
        <import namespace="urn:oasis:names:tc:SAML:1.0:assertion" schemaLocation="http://www.oasis-open.org/committees/security/docs/oasis-sstc-saml-schema-assertion-1.0.xsd"/>
        <import namespace="urn:oasis:names:tc:SAML:2.0:assertion" schemaLocation="oasis-sstc-saml-schema-assertion-2.0.xsd"/>
        <import namespace="urn:oasis:names:tc:SAML:1.0:protocol" schemaLocation="http://www.oasis-open.org/committees/security/docs/oasis-sstc-saml-schema-protocol-1.0.xsd"/>
        <import namespace="urn:oasis:names:tc:xacml:1.0:context" schemaLocation="http://www.oasis-open.org/committees/xacml/repository/cs-xacml-schema-context-01.xsd"/>
        <annotation>
                <documentation>
                Document identifier: oasis-sstc-saml-schema-protocol-2.0
                Location: 
                </documentation>
        </annotation>
        <element name="XCRequest" type="samlp2:XCRequestType"/>
        <complexType name="XCRequestType">
                <complexContent>
                        <extension base="samlp:RequestAbstractType">
                                <choice>
                                        <element ref="samlp:Query"/>
                                        <element ref="samlp:SubjectQuery"/>
                                        <element ref="samlp:AuthenticationQuery"/>
                                        <element ref="samlp:AttributeQuery"/>
                                        <element ref="samlp:AuthorizationDecisionQuery"/>
                                        <element ref="samlp2:XCAuthorizationDecisionQuery"/>
                                        <element ref="saml:AssertionIDReference" maxOccurs="unbounded"/>
                                        <element ref="samlp:AssertionArtifact" maxOccurs="unbounded"/>
                                </choice>
                        </extension>
                </complexContent>
        </complexType>
        <element name="XCAuthorizationDecisionQuery" type="samlp2:XCAuthorizationDecisionQueryType"/>
        <complexType name="XCAuthorizationDecisionQueryType">
                <complexContent>
                        <extension base="samlp:QueryAbstractType">
                                <sequence>
                                        <element ref="xacml-context:Request" />
                                </sequence>
                                <attribute name="InputContextOnly" type="boolean" use="required"/>
                                <attribute name="ReturnContext" type="boolean" use="required"/>
                        </extension>
                </complexContent>
        </complexType>
        <element name="XCResponse" type="samlp2:XCResponseType"/>
        <complexType name="XCResponseType">
                <complexContent>
                        <extension base="samlp:ResponseAbstractType">
                                <sequence>
                                        <element ref="samlp:Status"/>
                                        <element ref="saml2:XCAssertion" minOccurs="0" maxOccurs="unbounded"/>
                                </sequence>
                        </extension>
                </complexContent>
        </complexType>
</schema>