draft-zeilenga-ldap-authzid-xx.txt [plain text]
INTERNET-DRAFT Kurt D. Zeilenga
Intended Category: Standard Track OpenLDAP Foundation
Expires in six months 1 November 2002
LDAP "Who am I?" Operation
<draft-zeilenga-ldap-authzid-08.txt>
Status of this Memo
This document is an Internet-Draft and is in full conformance with all
provisions of Section 10 of RFC2026.
This document is intended to be, after appropriate review and
revision, submitted to the RFC Editor as a Standard Track document.
Distribution of this memo is unlimited. Technical discussion of this
document will take place on the IETF LDAP Extension Working Group
mailing list <ldapext@ietf.org>. Please send editorial comments
directly to the author <Kurt@OpenLDAP.org>.
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 2002, The Internet Society. All Rights Reserved.
Please see the Copyright section near the end of this document for
more information.
Abstract
This specification provides a mechanism for Lightweight Directory
Access Protocol (LDAP) clients to obtain the authorization identity
which the server has associated with the user or application entity.
This mechanism is specified as an LDAP extended operation called the
LDAP "Who am I?" operation.
Zeilenga LDAP "Who am I?" [Page 1]
INTERNET-DRAFT draft-zeilenga-ldap-authzid-08 1 November 2002
Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in BCP 14 [RFC2119].
1. Background and Intent of Use
This specification describes a Lightweight Directory Access Protocol
(LDAP) [RFC3377] operation which clients can use to obtain the primary
authorization identity in its primary form which the server has
associated with the user or application entity. The operation is
called the "Who am I?" operation.
This specification is intended to replace the existing [AUTHCTL]
mechanism which uses Bind request and response controls to request and
return the authorization identity. Bind controls are not protected by
the security layers established by the Bind operation which they are
transferred as part of. While it is possible to establish security
layers using Start TLS [RFC2830] prior to the Bind operation, it is
often desirable to use security layers established by the Bind
operation. An extended operation sent after a Bind operation is
protected by the security layers established by the Bind operation.
There are other cases where it is desirable to request the
authorization identity which the server associated with the client
separately from the Bind operation. For example, the "Who am I?"
operation can be augmented with a Proxied Authorization Control
[PROXYCTL] to determine the authorization identity which the server
associates with the identity asserted in the Proxied Authorization
Control. The "Who am I?" operation can also be used prior to the Bind
operation.
Servers often associate multiple authorization identities with the
client and each authorization identity may be represented by multiple
authzId [RFC2829] strings. This operation requests and returns the
authzId the server considers to be primary. In the specification, the
term "the authorization identity" and "the authzId" are generally to
be read as "the primary authorization identity" and the "the primary
authzId", respectively.
2. The "Who am I?" Operation
The "Who am I?" operation is defined as an LDAP Extended Operation
[RFC2251, Section 4.12] identified by the whoamiOID Object Identifier
(OID). This section details the syntax of the operation's whoami
Zeilenga LDAP "Who am I?" [Page 2]
INTERNET-DRAFT draft-zeilenga-ldap-authzid-08 1 November 2002
request and response messages.
whoamiOID ::= "1.3.6.1.4.1.4203.1.11.3"
2.1. The whoami Request
The whoami request is an ExtendedRequest with the requestName field
containing the whoamiOID OID and an absent requestValue field. For
example, a whoami request could be encoded as the sequence of octets
(in hex):
30 1e 02 01 02 77 19 80 17 31 2e 33 2e 36 2e 31
2e 34 2e 31 2e 34 32 30 33 2e 31 2e 31 31 2e 33
2.2. The whoami Response
The whoami response is an ExtendedResponse where the responseName
field is absent and the response field, if present, is empty or an
authzId [RFC2829]. For example, a whoami response returning the
authzId "u:kurt@OPENLDAP.ORG" (in response to the example request)
would be encoded as the sequence of octets (in hex):
30 21 02 01 02 78 1c 0a 01 00 04 00 04 00 8b 13
75 3a 6b 75 72 74 40 4f 50 45 4e 4c 44 41 50 2e
4f 52 47
3. Operational Semantics
The "Who am I?" operation provides a mechanism, a whoami Request, for
the client to request that the server returns the authorization
identity it currently associates with the client and provides a
mechanism, a whoami Response, for the server to respond to that
request.
If the server is willing and able to provide the authorization
identity it associates with the client, the server SHALL return a
whoami Response with a success resultCode. If the server is treating
the client as an anonymous entity, the response field is present but
empty. Otherwise the server provides the authzId [RFC2829]
representing the authorization identity it currently associates with
the client in the response field.
If the server is unwilling or unable to provide the authorization
identity it associates with the client, the server SHALL return a
whoami Response with an appropriate non-success resultCode (such as
Zeilenga LDAP "Who am I?" [Page 3]
INTERNET-DRAFT draft-zeilenga-ldap-authzid-08 1 November 2002
operationsError, protocolError, confidentialityRequired,
insufficientAccessRights, busy, unavailable, unwillingToPerform, or
other) and an absent response field.
As described in [RFC2251] and [RFC2829], an LDAP session has an
"anonymous" association until the client has been successfully
authenticated using the Bind operation. Clients MUST NOT invoke the
"Who Am I?" operation while any Bind operation is in progress,
including between two Bind requests made as part of a multi-stage Bind
operation.
4. Extending the "Who am I?" operation with controls
Future specifications may extend the "Who am I?" operation using the
control mechanism [RFC2251]. When extended by controls, the "Who am
I?" operation requests and returns the authorization identity the
server associates with the client in a particular context indicated by
the controls.
4.1. Proxied Authorization Control
The Proxied Authorization Control [PROXYCTL] is used by clients to
request that the operation it is attached to operates under the
authorization of an assumed identity. The client provides the
identity to assume in the Proxied Authorization request control. If
the client is authorized to assume the requested identity, the server
executes the operation as if the requested identity had issued the
operation.
As servers often map the asserted authzId to another identity
[RFC2829], it is desirable to request the server provide the authzId
it associates with the assumed identity.
When a Proxied Authorization Control is be attached to the "Who Am I?"
operation, the operation requests the return of the authzId the server
associates with the identity asserted in the Proxied Authorization
Control. The TBD result code is used to indicate that the server does
not allow the client to assume the asserted identity. [[Note to RFC
Editor: TBD is to be replaced with the name/code assigned by IANA for
[PROXYCTL] use.]]
5. Security Considerations
Identities associated with users may be sensitive information. When
so, security layers [RFC2829][RFC2830] should be established to
Zeilenga LDAP "Who am I?" [Page 4]
INTERNET-DRAFT draft-zeilenga-ldap-authzid-08 1 November 2002
protect this information. This mechanism is specifically designed to
allow security layers established by a Bind operation to protect the
integrity and/or confidentiality of the authorization identity.
Servers may place access control or other restrictions upon the use of
this operation.
As with any other extended operations, general LDAP security
considerations [RFC3377] apply.
6. IANA Considerations
This OID 1.3.6.1.4.1.4203.1.11.3 to identify the LDAP "Who Am I?
extended operation. This OID was assigned [ASSIGN] by OpenLDAP
Foundation, under its IANA-assigned private enterprise allocation
[PRIVATE], for use in this specification.
Registration of this protocol mechansism is requested [RFC3383].
Subject: Request for LDAP Protocol Mechansism Registration
Object Identifier: 1.3.6.1.4.1.4203.1.11.3
Description: Who am I?
Person & email address to contact for further information:
Kurt Zeilenga <kurt@openldap.org>
Usage: Extended Operation
Specification: RFCxxxx
Author/Change Controller: IESG
Comments: none
7. Acknowledgment
This document borrows from prior work in this area including
"Authentication Response Control" [AUTHCTL] by Rob Weltman, Mark Smith
and Mark Wahl.
The LDAP "Who am I?" operation takes it name from the UNIX whoami(1)
command. The whoami(1) command displays the effective user id.
Zeilenga LDAP "Who am I?" [Page 5]
INTERNET-DRAFT draft-zeilenga-ldap-authzid-08 1 November 2002
8. Author's Address
Kurt D. Zeilenga
OpenLDAP Foundation
<Kurt@OpenLDAP.org>
9. Normative References
[RFC2119] S. Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14 (also RFC 2119), March 1997.
[RFC2251] M. Wahl, T. Howes, S. Kille, "Lightweight Directory Access
Protocol (v3)", RFC 2251, December 1997.
[RFC2829] M. Wahl, H. Alvestrand, J. Hodges, RL "Bob" Morgan,
"Authentication Methods for LDAP", RFC 2829, June 2000.
[RFC2830] J. Hodges, R. Morgan, and M. Wahl, "Lightweight Directory
Access Protocol (v3): Extension for Transport Layer
Security", RFC 2830, May 2000.
[RFC3377] J. Hodges, R. Morgan, "Lightweight Directory Access
Protocol (v3): Technical Specification", RFC 3377,
September 2002.
[PROXYCTL] R. Weltman, "LDAP Proxied Authentication Control", draft-
weltman-ldapv3-proxy-xx.txt (a work in progress).
10. Informative References
[RFC3383] K. Zeilenga, "IANA Considerations for LDAP", BCP 64 (also
RFC 3383), September 2002.
[ASSIGN] OpenLDAP Foundation, "OpenLDAP OID Delegations",
http://www.openldap.org/foundation/oid-delegate.txt.
[AUTHCTL] R. Weltman, M. Smith, M. Wahl, "LDAP Authentication
Response Control", draft-weltman-ldapv3-auth-response-
xx.txt (a work in progress).
[PRIVATE] IANA, "Private Enterprise Numbers",
http://www.iana.org/assignments/enterprise-numbers.
Copyright 2002, The Internet Society. All Rights Reserved.
Zeilenga LDAP "Who am I?" [Page 6]
INTERNET-DRAFT draft-zeilenga-ldap-authzid-08 1 November 2002
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 AUTHORS, 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.
Zeilenga LDAP "Who am I?" [Page 7]