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Re: auth-response comments
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
"Kurt D. Zeilenga" wrote:
> 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
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
rweltman@netscape.com
Mark Smith
Netscape Communications Corp.
MV-068
501 E. Middlefield Rd.
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 1600
Mark.Wahl@innosoft.com
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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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