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Versions: 00 01 02 03 04 05 06 07 08 09 10 RFC 4532

INTERNET-DRAFT                                      Kurt D. Zeilenga
Intended Category: Standard Track                OpenLDAP Foundation
Expires in six months                                   1 March 2002



                        LDAP "Who am I?" Operation
                   <draft-zeilenga-ldap-authzid-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.

  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 <ietf-ldapext@netscape.com>.  Please send editorial
  comments directly to the author <Kurt@OpenLDAP.org>.

  Internet-Drafts are working documents of the Internet Engineering Task
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  Internet-Drafts are draft documents valid for a maximum of six months
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  material or to cite them other than as ``work in progress.''

  The list of current Internet-Drafts can be accessed at
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  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.



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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 LDAP [RFC2251] extended operation which
  clients can use to obtain the authorization identity which the server
  has associated with the user or application entity.

  This specification offers an alternative approach to [AUTHCTL] which
  uses Bind request and response controls to request and return an
  authzId.  However, Bind controls are not protected by the security
  layers established by the Bind operation which they are transferred as
  part of.  An extended operation sent after a Bind operation is
  protected by the security layers established by the Bind operation.

  There are also cases where it is desirable to request the authzId
  which server associated with the client separately from the Bind
  operation.  For example, the "Who am I?" operation can be augmented
  with a proxy authorization control [PROXYCTL] to determine the authzid
  to which the server associates with the identity asserted in the proxy
  control.  The "Who am I?" operation can also be used to determine the
  authorization identity associated with a proxy group [PROXYGRP].  The
  "Who am I?" operation can also be used prior to the Bind operation.

  The LDAP "Who am I?" operation is named after the UNIX whoami(1)
  command.  The whoami(1) command displays the effective user id.


2. The "Who am I?" Operation

  The "Who am I?" operation is defined as a LDAP Extended Operation
  [RFC2251, Section 4.12] identified by the whoamiOID Object Identifier
  (OID).  This section details the syntax of the operation's whoami
  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 whoamiOID OID and a requestValue field is absent.




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2.2. The whoami Response

  The whoami response is an ExtendedResponse where the responseName is
  absent and, if present, the response field is empty or an authzId
  [RFC2829].


3. Operational Semantics

  The function of the "Who am I?" operation is to request that the
  server return the authorization identity it currently associates with
  the client.

  The client requests this authorization identity by issuing a whoami
  Request.  The server responds to this request with an whoami Response.

  If the server is willing and able to provide the authorization
  identity it associates with the client, the server returns whoami
  Response with a success resultCode.  If the server is treating the
  client as an anonymous entity, the server response field SHALL be
  empty.  Otherwise the server SHALL provide 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 an
  whoami Response with a non-success resultCode and an absent response
  field.


4. Extending the "Who am I?" operation with controls

  Future specifications may extend the "Who am I?" operation using the
  control mechanism.  When extended by control, the "Who am I?"
  operation returns the authorization identity associated to the client
  in a particular context indicated by the control.


4.1. Proxy Control Who am I?

  The Proxy Control [PROXYCTL] is used by clients to request that the
  operation it is attached to operate under the authorization of an
  assumed identity.  The client provides the identity to assume in the
  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 requested authzid to another identity



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  [RFC2829], it is desirable to request the server provide the authzid
  it associates with the assumed identity.

  The Proxy Control MAY be attached to the "Who Am I?" operation to
  request and return the authzid the associates with the assumed
  identity.


4.2. Proxy Group Who am I?

  The Proxy Group [PROXYGRP] mechanism provides an alternative method
  for LDAP operations to be executed under the authorization of an
  assumed identity.  The Proxy Group mechanism consists of a create
  group operation, a set of operations executed under the authorization
  of the assume identity, and an end group operation.  A Proxy Group
  Control is attached to each operations to be executed under the
  authorization of the assumed identity.

  The Proxy Group Control MAY be attached to the "Who Am I?" operation
  to request and return the authzid the associates with the assumed
  identity.


5. Security Considerations

  Identities associated with users may be sensitive information.  When
  so, security layers [RFC2829][RFC2830] SHOULD be established to
  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 considerations
  apply.  These are detailed in [RFC2251], [RFC2829], and [RFC2830].


6. Acknowledgment

  This document borrows from prior work in this area including
  "Authentication Response Control" [AUTHCTL] by Rob Weltman, Mark Smith
  and Mark Wahl.


7. Author's Address

  Kurt D. Zeilenga



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  OpenLDAP Foundation
  <Kurt@OpenLDAP.org>


8. 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.

  [PROXYCTL] R. Weltman, "LDAP Proxied Authentication Control", draft-
             weltman-ldapv3-proxy-xx.txt (a work in progress).

  [PROXYGRP] K. Zeilenga, "LDAP Proxy Group", draft-zeilenga-ldap-
             proxygrp-xx.txt (a work in progress).


9. Informative References

  [AUTHCTL]  R. Weltman, M. Smith, M. Wahl, "LDAP Authentication
             Response Control", draft-weltman-ldapv3-auth-response-
             xx.txt (a work in progress).


Copyright 2002, The Internet Society.  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.




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  The limited permissions granted above are perpetual and will not be
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