Keywords: user mechanisms, extension
Network Working Group K. Zeilenga
Request for Comments: 3673 OpenLDAP Foundation
Category: Standards Track December 2003
Lightweight Directory Access Protocol version 3 (LDAPv3):
All Operational Attributes
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved.
Abstract
The Lightweight Directory Access Protocol (LDAP) supports a mechanism
for requesting the return of all user attributes but not all
operational attributes. This document describes an LDAP extension
which clients may use to request the return of all operational
attributes.
1. Overview
X.500 [X.500] provides a mechanism for clients to request all
operational attributes be returned with entries provided in response
to a search operation. This mechanism is often used by clients to
discover which operational attributes are present in an entry.
This documents extends the Lightweight Directory Access Protocol
(LDAP) [RFC3377] to provide a simple mechanism which clients may use
to request the return of all operational attributes. The mechanism
is designed for use with existing general purpose LDAP clients
(including web browsers which support LDAP URLs) and existing LDAP
APIs.
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].
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RFC 3673 LDAPv3: All Operational Attributes December 2003
2. All Operational Attributes
The presence of the attribute description "+" (ASCII 43) in the list
of attributes in a Search Request [RFC2251] SHALL signify a request
for the return of all operational attributes.
As with all search requests, client implementors should note that
results may not include all requested attributes due to access
controls or other restrictions. Client implementors should also note
that certain operational attributes may be returned only if requested
by name even when "+" is present. This is because some operational
attributes are very expensive to return.
Servers supporting this feature SHOULD publish the Object Identifier
1.3.6.1.4.1.4203.1.5.1 as a value of the 'supportedFeatures'
[RFC3674] attribute in the root DSE.
3. Interoperability Considerations
This mechanism is specifically designed to allow users to request all
operational attributes using existing LDAP clients. In particular,
the mechanism is designed to be compatible with existing general
purpose LDAP clients including those supporting LDAP URLs [RFC2255].
The addition of this mechanism to LDAP is not believed to cause any
significant interoperability issues (this has been confirmed through
testing). Servers which have yet to implement this specification
should ignore the "+" as an unrecognized attribute description per
[RFC2251, Section 4.5.1]. From the client's perspective, a server
which does not return all operational attributes when "+" is
requested should be viewed as having other restrictions.
It is also noted that this mechanism is believed to require no
modification of existing LDAP APIs.
4. Security Considerations
This document provides a general mechanism which clients may use to
discover operational attributes. Prior to the introduction of this
mechanism, operational attributes were only returned when requested
by name. Some might have viewed this as obscurity feature. However,
this feature offers a false sense of security as the attributes were
still transferable.
Implementations SHOULD implement appropriate access controls
mechanisms to restricts access to operational attributes.
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RFC 3673 LDAPv3: All Operational Attributes December 2003
5. IANA Considerations
This document uses the OID 1.3.6.1.4.1.4203.1.5.1 to identify the
feature described above. This OID was assigned [ASSIGN] by OpenLDAP
Foundation, under its IANA-assigned private enterprise allocation
[PRIVATE], for use in this specification.
Registration of this feature has been completed by IANA [RFC3674],
[RFC3383].
Subject: Request for LDAP Protocol Mechanism Registration
Object Identifier: 1.3.6.1.4.1.4203.1.5.1
Description: All Op Attrs
Person & email address to contact for further information:
Kurt Zeilenga <kurt@openldap.org>
Usage: Feature
Specification: RFC3673
Author/Change Controller: IESG
Comments: none
6. Acknowledgment
The "+" mechanism is believed to have been first suggested by Bruce
Greenblatt in a November 1998 post to the IETF LDAPext Working Group
mailing list.
7. Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11. Copies of
claims of rights made available for publication and any assurances of
licenses to be made available, or the result of an attempt made to
obtain a general license or permission for the use of such
proprietary rights by implementors or users of this specification can
be obtained from the IETF Secretariat.
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RFC 3673 LDAPv3: All Operational Attributes December 2003
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive
Director.
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2251] Wahl, M., Howes, T. and S. Kille, "Lightweight Directory
Access Protocol (v3)", RFC 2251, December 1997.
[RFC3377] Hodges, J. and R. Morgan, "Lightweight Directory Access
Protocol (v3): Technical Specification", RFC 3377,
September 2002.
[RFC3674] Zeilenga, K., "Feature Discovery in Lightweight Directory
Access Protocol (LDAP)", RFC 3674, December 2003.
8.2. Informative References
[RFC2255] Howes, T. and M. Smith, "The LDAP URL Format", RFC 2255,
December 1997.
[RFC3383] Zeilenga, K., "Internet Assigned Numbers Authority (IANA)
Considerations for the Lightweight Directory Access
Protocol (LDAP)", BCP 64, RFC 3383, September 2002.
[X.500] ITU-T Rec. X.500, "The Directory: Overview of Concepts,
Models and Service", 1993.
[ASSIGN] OpenLDAP Foundation, "OpenLDAP OID Delegations",
http://www.openldap.org/foundation/oid-delegate.txt.
[PRIVATE] IANA, "Private Enterprise Numbers",
http://www.iana.org/assignments/enterprise-numbers.
9. Author's Address
Kurt D. Zeilenga
OpenLDAP Foundation
EMail: Kurt@OpenLDAP.org
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RFC 3673 LDAPv3: All Operational Attributes December 2003
10. Full Copyright Statement
Copyright (C) The Internet Society (2003). All Rights Reserved.
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Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
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