Network Working Group                                        Rob Weltman 
INTERNET-DRAFT                                                Mark Smith 
Intended Category: Standards Track         Netscape Communications Corp. 
                                                               Mark Wahl 
                                                  Sun Microsystems, Inc. 
                                                          November, 2000 
 
    
                  LDAP Authentication Response Control 
               draft-weltman-ldapv3-auth-response-03.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 
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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]. 
    
    

  
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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 supportedExtension 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]. 
    
   The controlType is "2.16.840.1.113730.3.4.16", the criticality field 
   is FALSE or absent, and the controlValue is absent. 
    
    
4. Authentication Response Control 
    
   This control may be included in any final bind response where the 
   bind request 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, 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. 
 
   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 
  
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   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. 
    
    
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 
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF 
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 
    
    
7. Bibliography 
    

  
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   [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 
   +1 650 461 1708 
   robw@worldspot.com 
    
   Mark Smith 
   Netscape Communications Corp. 
   Mailstop USCA17-201 
   4170 Network Circle 
   Santa Clara, CA 95054 
   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 
    
 
    
9. Changes from draft-weltman-ldapv3-auth-response-02.txt 
    
   Authentication Response Control 
    
   The value of an Authentication Response Control is an authorization 
   identity, not necessarily a DN. 
    
    
   Security Considerations 
    
  
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   Added a short discussion of the fact that an identity is exposed in 
   the response control. 
    
    
   Miscellaneous 
    
   Eliminated BNF for control contents. 
    
    
10. 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. 
    
    
11. 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. 
 


















  
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