ABFAB J. Howlett Internet-Draft JANET(UK) Intended status: Informational S. Hartman Expires: September 11, 2011 Painless Security March 10, 2011 A RADIUS Attribute for SAML Messages draft-ietf-abfab-aaa-saml-01 Abstract This document defines the SAML-Message attribute for use with the RADIUS protocol. This attribute is used for encapsulating Security Assertion Mark-up Language (SAML) messages. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on September 11, 2011. Copyright Notice Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Howlett & Hartman Expires September 11, 2011 [Page 1] Internet-Draft An AAA Attribute for SAML Messages March 2011 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. SAML Message Attribute . . . . . . . . . . . . . . . . . . . . 3 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 4 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 4 6.1. Normative References . . . . . . . . . . . . . . . . . . . 4 6.2. Informative References . . . . . . . . . . . . . . . . . . 5 Howlett & Hartman Expires September 11, 2011 [Page 2] Internet-Draft An AAA Attribute for SAML Messages March 2011 1. Introduction The SAML-Message attribute has motivated by the requirements of the ABFAB architecture [I-D.lear-abfab-arch]. In this architecture, the attribute is used to convey Security Assertion Mark-up Language (SAML) messages between a SAML requester and responder. In the SAML model, the composition of such message exchanges with an underlying transport protocol is known as a SAML binding. SAML already defines [OASIS.saml-bindings-2.0-os] a number of mainly HTTP- based bindings, principally (although by no means exclusively) for use with the SAML Web Browser Single Sign-On Profile [OASIS.saml-profiles-2.0-os]. In the ABFAB architecture, AAA-based transport protocols are used to convey SAML messages. This document defines a RADIUS attribute required for binding SAML to RADIUS [RFC2865] transport. A draft document [1] exists that describes a proposed binding, but it has not yet been submitted to the OASIS Security Services Technical Committee. This is pending conclusions on the following aspects of the ABFAB architecture: o The use of the SAML attribute query at some arbitrary time after the initial EAP authentication exchange. o The use of the SAML attribute query to obtain attributes for a principal from more than one attribute authority. o Alignment with the Diameter ABFAB application [I-D.jones-diameter-abfab]. This attribute is likely to be useful for other purposes besides ABFAB; an example of a potential application is SAML-based authorisation for network access. 2. Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. 3. SAML Message Attribute This attribute contains a SAML [OASIS.saml-core-2.0-os] message. Where multiple SAML-Message attributes are included in a RADIUS message, the Message fields of these attributes are to be concatenated to form a single SAML message. Howlett & Hartman Expires September 11, 2011 [Page 3] Internet-Draft An AAA Attribute for SAML Messages March 2011 A summary of the SAML-Message format is shown below. The fields are transmitted from left to right. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | SAML Message... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1 Type: TBD Length: >=4 Message: The Message field is one or more octets containing a SAML message. If larger than a single attribute, the SAML message data MUST be split on 253-octet boundaries over as many attributes as necessary. The SAML message is reconstructed by concatenating the contents of all SAML-Message attributes. 4. Security Considerations TODO 5. IANA Considerations Assignments of additional enumerated values for the RADIUS attributes defined in this document are to be processed as described in [RFC3575], subject to the additional requirements of a published specification. 6. References 6.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson, "Remote Authentication Dial In User Service (RADIUS)", RFC 2865, June 2000. [OASIS.saml-core-2.0-os] Cantor, S., Kemp, J., Philpott, R., and E. Maler, "Assertions and Protocol for the OASIS Security Assertion Markup Howlett & Hartman Expires September 11, 2011 [Page 4] Internet-Draft An AAA Attribute for SAML Messages March 2011 Language (SAML) V2.0", OASIS Standard saml-core-2.0-os, March 2005. [RFC3575] Aboba, B., "IANA Considerations for RADIUS (Remote Authentication Dial In User Service)", RFC 3575, July 2003. 6.2. Informative References [I-D.jones-diameter-abfab] Jones, M. and H. Tschofenig, "The Diameter 'Application Bridging for Federated Access Beyond Web (ABFAB)' Application", draft-jones-diameter-abfab-00 (work in progress), March 2011. [I-D.lear-abfab-arch] Howlett, J., Hartman, S., Tschofenig, H., and E. Lear, "Application Bridging for Federated Access Beyond Web (ABFAB) Architecture", draft-lear-abfab-arch-02 (work in progress), March 2011. [OASIS.saml-bindings-2.0-os] Cantor, S., Hirsch, F., Kemp, J., Philpott, R., and E. Maler, "Bindings for the OASIS Security Assertion Markup Language (SAML) V2.0", OASIS Standard saml-bindings-2.0-os, March 2005. [OASIS.saml-profiles-2.0-os] Hughes, J., Cantor, S., Hodges, J., Hirsch, F., Mishra, P., Philpott, R., and E. Maler, "Profiles for the OASIS Security Assertion Markup Language (SAML) V2.0", OASIS Standard OASIS.saml-profiles-2.0-os, March 2005. URIs [1] Howlett & Hartman Expires September 11, 2011 [Page 5] Internet-Draft An AAA Attribute for SAML Messages March 2011 Authors' Addresses Josh Howlett JANET(UK) Lumen House, Library Avenue, Harwell Oxford OX11 0SG UK Phone: +44 1235 822363 EMail: Josh.Howlett@ja.net Sam Hartman Painless Security Phone: EMail: hartmans-ietf@mit.edu Howlett & Hartman Expires September 11, 2011 [Page 6]