Internet-Draft Keromytis, Angelos D. Expires: April 7, 2009 Columbia University Intended Status: Informational October 7, 2009 Filename: draft-keromytis-tls-authz-keynote-03.txt Transport Layer Security (TLS) Authorization Using KeyNote Status of this Memo This Internet-Draft is submitted to the IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Copyright Notice Copyright (c) 2009 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/licenseinfo) 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 BSD License. Abstract This document specifies the use of the KeyNote trust-management system as an authorization extension in the Transport Layer Security (TLS) Handshake Protocol, according to [AUTHZ]. Extensions carried in the client and server hello messages confirm that both parties support the desired authorization data types. Then, if supported by both the client and the server, KeyNote credentials are exchanged during the supplemental data handshake message. 1. Introduction This document describes the identifiers necessary to exchange KeyNote [KEYNOTE] credential assertions inside a TLS [TLS1.0] [TLS1.1] [TLS1.2] exchange. Such credential assertions can authorize the client and/or the server to perform certain actions. In most usage scenarios, the KeyNote credential assertions will be signed by a cryptographic public key [RFC2792]. By using the X.509 key and signature encoding [X509KEY], it is possible to add KeyNote-based authorization and policy compliance support to the existing, unmodified X.509 authentication exchange in TLS. A list of KeyNote credentials (e.g., forming a delegation chain) may be sent as part of the same payload. Alternatively, a URL pointing to the location of such a list of KeyNote credentials may be provided. In most scenarios, at least one of these credentials will be issued to the public key of the transmitter of the credentials, i.e., said public key will appear in the ``Licensees'' field of at least one KeyNote credential assertion. The same public key will generally be used by the transmitter of the same credentials to authenticate as part of the TLS exchange. The authentication material (e.g., cryptographic public key) that was used by the transmitter to authenticate in the TLS exchange will be provided to the KeyNote evaluation engine as an ``Action Authorizer''. 2. KeyNote Credential Assertion Lists The KeyNote Assertion List type definition in the TLS Authorization Data Formats registry is: keynote_assertion_list(TBA) When the keynote_assertion_list value is present, the authorization data is a list of KeyNote credential assertions that conforms to the profile in RFC 2704 [KEYNOTE]. A KeyNote assertion list is transmitted inside an AuthorizationDataEntry structure as an opaque sequence of 1 - 2^16-1 bytes: opaque KeyNoteAssertionList<1..2^16-1>; When KeyNoteAssertionList is used, the field contains an ASCII- encoded list of signed KeyNote assertions, as described in RFC 2704 [KEYNOTE]. The assertions are separated by two '\n' (newline) characters. A KeyNote assertion is a structure similar to a public key certificate; the main difference is that instead of a binding between a name and a public key, KeyNote assertions bind public keys to authorization rules that are evaluated by the peer when the sender later issues specific requests. When making an authorization decision based on a list of KeyNote assertions, proper linkage between the KeyNote assertions and the public key certificate that is transferred in the TLS Certificate message is needed. Receivers of a KeyNote assertion list should initialize the ACTION_AUTHORIZER variable to be the sender's public key, which was used to authenticate the TLS exchange. If a different authentication mechanism is used, it is the responsibility of the credential issuer to issue the appropriate credentials. 3. KeyNote Credential Assertion List URL The KeyNote Assertion List URL type definition in the TLS Authorization Data Formats registry is: keynote_assertion_list_url(TBA) When the keynote_assertion_list_url value is present, the authorization data is a list of KeyNote assertions as described in Section 2; however the KeyNote assertion list is fetched with the supplies URL. A one-way hash value is provided to ensure that the intended KeyNote credential assertion is obtained. Implementations that support keynote_assertion_list_url MUST support URLs that employ the http scheme [UPGRADE]. These implementations MUST confirm that the hash value computed on the fetched authorization matches the one received in the handshake. Mismatch of the hash values SHOULD be treated as though the authorization was not provided, which will result in a bad_certificate alert [AUTHZ]. 4. IANA Considerations This document requires a new entry in the IANA-maintained TLS Authorization Data Formats registry, keynote_assertion_list(TBD). This registry is defined in [AUTHZ]. 5. Security Considerations There are no security considerations beyond those discussed in [KEYNOTE], [RFC2792], and [AUTHZ]. 6. Normative References [IANA] Narten, T., and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", RFC 3434, October 1998. [TLS1.0] Dierks, T., and C. Allen, "The TLS Protocol, Version 1.0", RFC 2246, January 1999. [TLS1.1] Dierks, T., and E. Rescorla, "The Transport Layer Security (TLS) Protocol, Version 1.1", RFC 4346, February 2006. [TLS1.2] Dierks, T., and E. Rescorla, "The Transport Layer Security (TLS) Protocol, Version 1.2", RFC 5246, August 2008. [UPGRADE] Khare, R., and S. Lawrence, "Upgrading to TLS Within HTTP/1.1", RFC 2817, May 2000. 7. Informative References [KEYNOTE] Blaze, M., Feigenbaum, J., Ioannidis, J., and A. Keromytis, "The KeyNote Trust-Management System, Version 2", RFC 2704, September 1999. [RFC2792] Blaze, M., Ioannidis, J., and A. Keromytis, "DSA and RSA Key and Signature Encoding for the KeyNote Trust Management System", RFC 2792, March 2000. [AUTHZ] Brown, M., and R. Housley, "Transport Layer Security (TLS) Authorization Extensions", September 2009 [X509KEY] A. D. Keromytis, "X.509 Key and Signature Encoding for the KeyNote Trust Management System", April 2009 Authors' Addresses Angelos D. Keromytis Department of Computer Science Columbia University Mail Code 0401 1214 Amsterdam Avenue New York, New York 1007 USA angelos cs columbia edu