INTERNET-DRAFT Rob Weltman Intended Category: Standards Track Mark Smith Netscape Communications Corp. Mark Wahl Sun Microsystems, Inc. November, 2001 LDAP Authentication Response Control draft-weltman-ldapv3-auth-response-05.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet 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. Abstract This document defines support for the Authentication Request Control and the Authentication Response Control. Controls are an LDAP protocol version 3 extension, to allow passing arbitrary control information along with a standard request to a server, and to receive arbitrary information back with a standard result. The Authentication Request Control may be submitted by a client in a bind request if authenticating with version 3 of the LDAP protocol. In the LDAP server's bind response, it may then include an Authentication Response Control. The response control contains the identity assumed by the client. This is useful when there is a mapping step or other indirection during the bind, so that the client can be told what LDAP identity was granted. Client authentication with certificates is the primary situation where this applies. Also, some SASL authentication mechanisms may not involve the client explicitly providing a DN, or may result in an authorization identity which is different from the authentication identity provided by the client [AUTH]. Expires May 2002 [Page 1] AUTHENTICATION RESPONSE CONTROL November, 2001 1. Introduction Version 3 of the LDAP protocol provides a means of supplying arbitrary additional information along with a request to an LDAP server, and receiving arbitrary additional response information. The Control protocol extension is described in [LDAPv3], section 4.1.12. This document defines a way for a server to return the identity assumed by a client on binding using the Control mechanism. The key words "MUST", "SHOULD", and "MAY" used in this document are to be interpreted as described in [RFCKeyWords]. 2. Publishing support for the Authentication Request Control and the Authentication Response Control Support for the Authentication Request Control and the Authentication Response Control is indicated by the presence of the OIDs 2.16.840.1.113730.3.4.16 and 2.16.840.1.113730.3.4.15, respectively, in the supportedControl attribute of a server's root DSE. 3. Authentication Request Control This control MAY be included in any bind request which specifies protocol version 3, as part of the controls field of the LDAPMessage as defined in [LDAPv3]. In a multi-step bind operation, the server SHOULD ignore occurrences of the control in bind requests other than the initial one. The controlType is "2.16.840.1.113730.3.4.16" and the controlValue is absent. 4. Authentication Response Control This control may be included in any final bind response where the first bind request of the bind operation included an Authentication Request Control as part of the controls field of the LDAPMessage as defined in [LDAPv3]. The controlType is "2.16.840.1.113730.3.4.15". If the bind request succeeded and resulted in an identity (not anonymous), the controlValue contains the authorization identity (authzId), as defined in [AUTH] section 9, granted to the requestor. If the bind request resulted in anonymous authentication, the controlValue field is a string of zero length. If the bind request failed, the control is not included in the bind response. Expires May 2002 [Page 2 AUTHENTICATION RESPONSE CONTROL November, 2001 During client authentication with certificates [AUTH], a client may possess more than one certificate and not be able to determine which one was ultimately selected for authentication to the server. The subject DN field in the selected certificate may not correspond exactly to a DN in the directory, but rather have gone through a mapping process controlled by the server. On completing the certificate-based authentication, the client may issue a SASL [SASL] bind request, specifying the EXTERNAL mechanism and including an Authentication Request Control. The bind response MAY include an Authentication Response Control indicating the DN in the server's DIT which the certificate was mapped to. 5. Security Considerations The Authentication Response Control is subject to standard LDAP security considerations. The control may be passed over a secure as well as over an insecure channel. It is not protected by security layers negotiated by the bind operation. The control allows for an additional authorization identity to be passed. In some deployments, these identities may contain confidential information which require privacy protection. In such deployments, a security layer should be established prior to issuing a bind request with an Authentication Request Control. 6. Copyright Copyright (C) The Internet Society (2000). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION Expires May 2002 [Page 3 AUTHENTICATION RESPONSE CONTROL November, 2001 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 7. Bibliography [LDAPv3] M. Wahl, T. Howes, S. Kille, "Lightweight Directory Access Protocol (v3)", RFC 2251, December 1997. [RFCKeyWords] Bradner, Scott, "Key Words for use in RFCs to Indicate Requirement Levels", draft-bradner-key-words-03.txt, January, 1997. [AUTH] M. Wahl, H. Alvestrand, J. Hodges, RL "Bob" Morgan, "Authentication Methods for LDAP", RFC 2829, May, 2000. [SASL] J. Myers, "Simple Authentication and Security Layer (SASL", RFC 2222, October, 1997. [ASN.1] X.680 : ITU-T Recommendation X.680 (1997) | ISO/IEC 8824- 1:1998, Information Technology - Abstract Syntax Notation One (ASN.1): Specification of Basic Notation 8. Author's Addresses Rob Weltman Netscape Communications Corp. 466 Ellis Street Mountain View, CA 94043 USA +1 650 937-3194 rweltman@netscape.com Mark Smith Netscape Communications Corp. 466 Ellis Street Mountain View, CA 94043 USA +1 650 937-3477 mcs@netscape.com Mark Wahl Sun Microsystems, Inc. 911 Capital of Texas Hwy, Suite 4140 Austin, TX 78759 USA +1 512 231 7224 Mark.Wahl@sun.com Expires May 2002 [Page 4 AUTHENTICATION RESPONSE CONTROL November, 2001 9. Revision history 9.1 Changes from draft-weltman-ldapv3-auth-response-04.txt Authentication Request Control Removed clause saying that the control may not be marked critical. Added sentence stating that the server should ignore authentication request controls other than on the first bind request in a multi-step bind operation. Authentication Response Control Added "(authzId)" to "authorization identity". Security Considerations Added a sentence recommending that a security layer be negotiated before issuing a bind request with the authentication request control in deployments where the authorization identity requires privacy protection. 9.2 No Changes from draft-weltman-ldapv3-auth-response-03.txt No changes 9.3 Changes from draft-weltman-ldapv3-auth-response-02.txt Publishing support The controls are published in supportedControl, not supportedExtension. Authentication Response Control The value of an Authentication Response Control is an authorization identity, not necessarily a DN. Security Considerations Added a short discussion of the fact that an identity is exposed in the response control. Expires May 2002 [Page 5 AUTHENTICATION RESPONSE CONTROL November, 2001 Miscellaneous Eliminated BNF for control contents. 9.4 Changes from draft-weltman-ldapv3-auth-response-01.txt Authentication Request Control An Authentication Response Control is now only returned if the client requested one by submitting an Authentication Request Control. Contents of Authentication Response Control Rather than returning both the authentication DN and the authentication mechanism, the control only returns the authentication DN. 9.5 Changes from draft-weltman-ldapv3-auth-response-00.txt Capitalization of ASN.1 macros AuthResponseControl and AuthResponseValue are capitalized. Clarifications Added sentence on behavior for anonymous binds. Expires May 2002 [Page 6