Subject: auth-response comments

From: "Kurt D. Zeilenga" <[email-masked]>
Date: Wed, 26 Jul 2000 23:33:57 -0700

Rob/Mark,

Here are some comments, some new, some old... all provided to
ensure completeness.

First, please note my general aversion to unsolicited controls.
IMO, controls should only be sent to clients which are known to
be able to make use of the information.

2. Publishing support for the Authentication Response Control

s/supportedExtensions/supportedControl/

3. Authentication Response

>The criticality field is not used.
I would suggest "The criticality of this control SHALL be
FALSE.  Servers SHOULD not provide the criticality field."

Not also that the controlType is determined, its the value
of the field which is TBD.

You do not specify how AuthResponseValue is to be encoded.

I do not see the need for authMechanism?  The client knows
the method and, if applicable, the SASL mechanism used.  However,
what might be useful is source of credential used to in
to complete a SASL/EXTERNAL authentication.

I note you specify the return of a DN and not an authzID.
You assume that if an userzID is provided (or implied)
by the client that it must be mapped to a DN and if a
DN is provided (or implied) that it is not mapped to
a userzID.  JeffH has made arguments that authzId should
be the general form of LDAP authorization information.
In fact, LDAP ACM allows authzID as subjects.  You likely
should consider changing authDN to authzID.

4. Security Considerations

Please make specific mention that the control is not
protected by SASL integrity and privacy services
negotiated by the bind operation it is provided with.
Due to this, I suggest use of a separate (extended)
operation instead of a bind control to request/return
this information.

	Kurt

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From: [email-masked] (Rob Weltman)
Date: Thu, 27 Jul 2000 18:30:20 -0700

Darn - I wrote up a revision of the document in April, taking into account all the input from you and others, but I was waiting for the other authors to sign. Well, here it is, anyway.

Rob

> operation instead of a bind control to request/return

Network Working Group                                        Rob Weltman
INTERNET-DRAFT                             Netscape Communications Corp.
                                                              Mark Smith
                                           Netscape Communications Corp.
                                                               Mark Wahl
                                                  Sun Microsystems, Inc.
                                                             April, 2000

                  LDAP Authentication Response Control
               draft-weltman-ldapv3-auth-response-02.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.

1. Introduction

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AUTHENTICATION RESPONSE CONTROL                            April, 2000

   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 supportedExtensions 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].

   AuthRequestControl ::= SEQUENCE {
           controlType     2.16.840.1.113730.3.4.16,
           criticality     BOOLEAN DEFAULT FALSE,
           controlValue    NULL
   }

   The criticality field is false or 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].

   AuthResponseControl ::= SEQUENCE {
           controlType     2.16.840.1.113730.3.4.15,
           criticality     BOOLEAN DEFAULT FALSE,
           controlValue    AuthDN LDAPDN
   }

   If the bind request failed, the control is not included in the bind
   response. If the bind request resulted in anonymous authentication,
   the controlValue field is a string of zero length.

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AUTHENTICATION RESPONSE CONTROL                            April, 2000

   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. No additional confidential
   information is passed in the 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
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

7. Bibliography

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AUTHENTICATION RESPONSE CONTROL                            April, 2000

   [LDAPv3] M. Wahl, T. Howes, S. Kille, "Lightweight Directory Access
        Protocol (v3)", Internet Draft draft-ietf-asid-ldapv3-protocol-
        06.txt, July 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", draft-ietf-ldapext-authmeth-
        04.txt, June, 1999.

   [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.
   MV-068
   501 E. Middlefield Rd.
   Mountain View, CA 94043
   USA
   +1 650 937-3301
   [email-masked]

   Mark Smith
   Netscape Communications Corp.
   MV-068
   501 E. Middlefield Rd.
   Mountain View, CA 94043
   USA
   +1 650 937-3477
   [email-masked]

   Mark Wahl
   Sun Microsystems, Inc.
   911 Capital of Texas Hwy, Suite 4140
   Austin, TX 78759
   USA
   +1 512 231 1600
   [email-masked]

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AUTHENTICATION RESPONSE CONTROL                            April, 2000

9. Changes from draft-weltman-ldapv3-auth-response-01.txt

9.1 Authentication Request Control

   An Authentication Response Control is now only returned if the client
   requested one by submitting an Authentication Request Control.

9.2 Contents of Authentication Response Control

   Rather than returning both the authentication DN and the
   authentication mechanism, the control only returns the authentication
   DN.

10. Changes from draft-weltman-ldapv3-auth-response-00.txt

10.1 Capitalization of ASN.1 macros

   AuthResponseControl and AuthResponseValue are capitalized.

10.2 Clarifications

   Added sentence on behavior for anonymous binds.

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From: [email-masked] (Rob Weltman)
Date: Thu, 27 Jul 2000 07:08:52 -0700

Darn. I had accomodated (or at least taken into account) all of your comments and written a new draft two months ago, but I was waiting for comments from Mark Wahl before republishing it. Well, anyway, I'm attaching it now.

Rob

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From: "David Chadwick" <[email-masked]>
Date: Sun, 30 Jul 2000 13:17:00 +0100

> be able to make use of the information.

I would concurr with this. In the general case, the client initiates a 
request and might use a control. This then gives the server the 
opportunity to put related controls in the response. If the client does 
not use a control, the server should assume the client is uninformed 
about them.

David

***************************************************

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IS Institute, University of Salford, Salford M5 4WT
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From: [email-masked] (Rob Weltman)
Date: Sun, 30 Jul 2000 18:07:43 -0700

The revised version of the draft (from April, sent to the list last week) makes it a requested response.

Rob