Independent Submission                                        R. Sinnema
Request for Comments: 7061                                      E. Wilde
Category: Informational                                  EMC Corporation
ISSN: 2070-1721                                            November 2013


    eXtensible Access Control Markup Language (XACML) XML Media Type

Abstract

   This specification registers an XML-based media type for the
   eXtensible Access Control Markup Language (XACML).

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This is a contribution to the RFC Series, independently of any other
   RFC stream.  The RFC Editor has chosen to publish this document at
   its discretion and makes no statement about its value for
   implementation or deployment.  Documents approved for publication by
   the RFC Editor are not a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7061.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 2
   2.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 2
     2.1.  XACML Media Type application/xacml+xml  . . . . . . . . . . 2
   3.  Security Considerations . . . . . . . . . . . . . . . . . . . . 5
   4.  Normative References  . . . . . . . . . . . . . . . . . . . . . 5
   Appendix A.  Acknowledgements . . . . . . . . . . . . . . . . . . . 6

1.  Introduction

   The eXtensible Access Control Markup Language (XACML) [XACML-3]
   defines an architecture and a language for access control
   (authorization).  The language consists of requests, responses, and
   policies.  Clients send a request to a server to query whether a
   given action should be allowed.  The server evaluates the request
   against the available policies and returns a response.  The policies
   implement the organization's access control requirements.

2.  IANA Considerations

   This specification details the registry of an XML-based media type
   for the eXtensible Access Control Markup Language (XACML) that has
   been registered with the Internet Assigned Numbers Authority (IANA)
   following the "Media Type Specifications and Registration Procedures"
   [RFC6838].  The XACML media type represents an XACML request,
   response, or policy in the XML-based format defined by the core XACML
   specification [XACML-3].

2.1.  XACML Media Type application/xacml+xml

   This specification details the registration of an XML-based media
   type for the eXtensible Access Control Markup Language (XACML).

   Media Type Name: application

   Subtype Name: xacml+xml

   Required Parameters: none

   Optional Parameters:

      charset: The charset parameter is the same as the charset
      parameter of application/xml [RFC3023], including the same default
      (see Section 3.2 of RFC 3023).

      version: The version parameter indicates the version of the XACML
      specification.  It can be used for content negotiation when
      dealing with clients and servers that support multiple XACML
      versions.  Its range is the range of published XACML versions.  As
      of this writing, that is 1.0 [XACML-1], 1.1 [XACML-1.1], 2.0
      [XACML-2], and 3.0 [XACML-3].  These and future version
      identifiers must follow the Organization for the Advancement of
      Structured Information Standards (OASIS) patterns for versions
      [OASIS-Version].  If this parameter is not specified by the
      client, the server is free to return any version it deems fit.  If
      a client cannot or does not want to deal with that, it should
      explicitly specify a version.

   Encoding Considerations: Same as for application/xml [RFC3023].

   Security Considerations:

      Per their specification, objects of type application/xacml+xml do
      not contain executable content.  However, these objects are XML-
      based, and thus they have all of the general security
      considerations presented in Section 10 of RFC 3023 [RFC3023].

      XACML [XACML-3] contains information about whose integrity and
      authenticity is important -- identity provider and service
      provider public keys and endpoint addresses, for example.
      Sections 9.2.1 "Authentication" and 9.2.4 "Policy Integrity" in
      XACML [XACML-3] describe requirements and considerations for such
      authentication and integrity protection.

      To counter potential issues, the publisher may sign objects of
      type application/xacml+xml.  Any such signature should be verified
      -- both as a valid signature and as being the signature of the
      publisher -- by the recipient of the data.  The XACML v3.0 XML
      Digital Signature Profile [XACML-3-DSig] describes how to use XML-
      based digital signatures with XACML.

      Additionally, various possible publication protocols, for example,
      HTTPS, offer means for ensuring the authenticity of the publishing
      party and for protecting the policy in transit.

      Interoperability Considerations: Different versions of XACML use
      different XML namespace URIs:

      *  1.0 and 1.1 use the urn:oasis:names:tc:xacml:1.0:policy XML
         namespace URI for policies and the
         urn:oasis:names:tc:xacml:1.0:context XML namespace URI for
         requests and responses

      *  2.0 uses the urn:oasis:names:tc:xacml:2.0:policy XML namespace
         URI for policies and the urn:oasis:names:tc:xacml:2.0:context
         XML namespace URI for requests and responses

      *  3.0 uses the urn:oasis:names:tc:xacml:3.0:core:schema:wd-17 XML
         namespace URI for policies, requests, and responses

      Signed XACML has a wrapping Security Assertion Markup Language
      (SAML) 2.0 assertion [SAML-2], which uses the
      urn:oasis:names:tc:SAML:2.0:assertion namespace URI.
      Interoperability with SAML is defined by the SAML 2.0 Profile of
      XACML [XACML-3-SAML] for all versions of XACML.

   Applications That Use This Media Type:

      Potentially, any application implementing or using XACML, as well
      as those applications implementing or using specifications based
      on XACML.  In particular, applications using the Representational
      State Transfer (REST) Profile [XACML-REST] can benefit from this
      media type.

   Magic Number(s):

      In general, this is the same as for application/xml [RFC3023].  In
      particular, the XML document element of the returned object will
      be one of xacml:Policy, xacml:PolicySet, context:Request, or
      context:Response.  The xacml and context namespace prefixes bind
      to the respective namespace URIs for the various versions of XACML
      as follows:

      *  1.0 and 1.1: The xacml prefix maps to
         urn:oasis:names:tc:xacml:1.0:policy; the context prefix maps to
         urn:oasis:names:tc:xacml:1.0:context

      *  2.0: The xacml prefix maps to
         urn:oasis:names:tc:xacml:2.0:policy; the context prefix maps to
         urn:oasis:names:tc:xacml:2.0:context

      *  3.0: Both the xacml and context prefixes map to the namespace
         URI urn:oasis:names:tc:xacml:3.0:core:schema:wd-17

      For signed XACML [XACML-3-DSig], the XML document element is saml:
      Assertion, where the saml prefix maps to the SAML 2.0 namespace
      URI urn:oasis:names:tc:SAML:2.0:assertion [SAML-2].

   File Extension(s): none

   Macintosh File Type Code(s): none

   Person & Email Address to Contact for Further Information:

      This registration is made on behalf of the OASIS eXtensible Access
      Control Markup Language Technical Committee (XACMLTC).  Please
      refer to the XACMLTC website for current information on committee
      chairperson(s) and their contact addresses:
      http://www.oasis-open.org/committees/xacml/.  Committee members
      should submit comments and potential errors to the
      xacml@lists.oasis-open.org list.  Others should submit them by
      filling out the web form located at http://www.oasis-open.org/
      committees/comments/form.php?wg_abbrev=xacml.

      Additionally, the XACML developer community email distribution
      list, xacml-dev@lists.oasis-open.org, may be employed to discuss
      usage of the application/xacml+xml MIME media type.  The xacml-dev
      mailing list is publicly archived here:
      http://www.oasis-open.org/archives/xacml-dev/.  To post to the
      xacml-dev mailing list, one must subscribe to it.  To subscribe,
      visit the OASIS mailing list page at
      http://www.oasis-open.org/mlmanage/.

   Intended Usage: common

   Author/Change Controller:

      The XACML specification sets are a work product of the OASIS
      eXtensible Access Control Markup Language Technical Committee
      (XACMLTC).  OASIS and the XACMLTC have change control over the
      XACML specification sets.

3.  Security Considerations

   The security considerations for this specification are described in
   Section 2.1 of the media type registration.


4.  Normative References

   [OASIS-Version]
              Organization for the Advancement of Structured Information
              Standards, "OASIS Naming Directives Version 1.3",
              December 2012, <http://docs.oasis-open.org/specGuidelines/
              ndr/namingDirectives.html#Version>.

   [RFC3023]  Murata, M., St. Laurent, S., and D. Kohn, "XML Media
              Types", RFC 3023, January 2001.

   [RFC6838]  Freed, N., Klensin, J., and T. Hansen, "Media Type
              Specifications and Registration Procedures", BCP 13,
              RFC 6838, January 2013.

   [SAML-2]   Organization for the Advancement of Structured Information
              Standards, "Assertions and Protocols for the OASIS
              Security Assertion Markup Language (SAML) V2.0",
              OASIS Standard, March 2005, <http://docs.oasis-open.org/
              security/saml/v2.0/saml-core-2.0-os.pdf>.

   [XACML-1]  Organization for the Advancement of Structured Information
              Standards, "eXtensible Access Control Markup Language
              (XACML) Version 1.0", OASIS Standard, February 2003,
              <http://www.oasis-open.org/committees/download.php/2406/
              oasis-xacml-1.0.pdf>.

   [XACML-1.1]
              Organization for the Advancement of Structured Information
              Standards, "eXtensible Access Control Markup Language
              (XACML) Version 1.1", OASIS Committee Specification,
              August 2003, <http://www.oasis-open.org/committees/xacml/
              repository/cs-xacml-specification-1.1.pdf>.

   [XACML-2]  Organization for the Advancement of Structured Information
              Standards, "eXtensible Access Control Markup Language
              (XACML) Version 2.0", OASIS Standard, February 2005,
              <http://docs.oasis-open.org/xacml/2.0/
              access_control-xacml-2.0-core-spec-os.pdf>.

   [XACML-3]  Organization for the Advancement of Structured Information
              Standards, "eXtensible Access Control Markup Language
              (XACML) Version 3.0", OASIS Standard, January 2013,
              <http://docs.oasis-open.org/xacml/3.0/
              xacml-3.0-core-spec-os-en.pdf>.

   [XACML-3-DSig]
              Organization for the Advancement of Structured Information
              Standards, "XACML v3.0 XML Digital Signature Profile
              Version 1.0", OASIS Committee Specification 01,
              August 2010, <http://docs.oasis-open.org/xacml/3.0/
              xacml-3.0-dsig-v1-spec-cs-01-en.pdf>.

   [XACML-3-SAML]
              Organization for the Advancement of Structured Information
              Standards, "SAML 2.0 Profile of XACML, Version 2.0", OASIS
              Committee Specification 01, August 2010,
              <http://docs.oasis-open.org/xacml/3.0/
              xacml-profile-saml2.0-v2-spec-cs-01-en.pdf>.

   [XACML-REST]
              Organization for the Advancement of Structured Information
              Standards, "REST Profile of XACML v3.0 Version 1.0", OASIS
              Committee Specification 01, April 2013,
              <http://docs.oasis-open.org/xacml/xacml-rest/v1.0/
              xacml-rest-v1.0.pdf>.

Appendix A.  Acknowledgements

   The following individuals have participated in the creation of this
   specification and are gratefully acknowledged: Oscar Koeroo (Nikhef),
   Erik Rissanen (Axiomatics), and Jonathan Robie (EMC).

Authors' Addresses

   Remon Sinnema
   EMC Corporation

   EMail: remon.sinnema@emc.com
   URI:   http://securesoftwaredev.com/


   Erik Wilde
   EMC Corporation
   6801 Koll Center Parkway
   Pleasanton, CA 94566
   USA

   Phone: +1-925-600-6244
   EMail: erik.wilde@emc.com
   URI:   http://dret.net/netdret/