Network Working Group K. Zeilenga

Network Working Group K. Zeilenga
Request for Comments: 4530 OpenLDAP Foundation
Category: Standards Track June 2006

Lightweight Directory Access Protocol (LDAP)
entryUUID Operational Attribute

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 (2006).

Abstract

This document describes the LDAP/X.500 'entryUUID' operational
attribute and associated matching rules and syntax. The attribute
holds a server-assigned Universally Unique Identifier (UUID) for the
object. Directory clients may use this attribute to distinguish
objects identified by a distinguished name or to locate an object
after renaming.

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RFC 4530 LDAP entryUUID June 2006

Table of Contents

1. Background and Intended Use .....................................2
2. UUID Schema Elements ............................................3
2.1. UUID Syntax ................................................3
2.2. 'uuidMatch' Matching Rule ..................................3
2.3. 'uuidOrderingMatch' Matching Rule ..........................3
2.4. 'entryUUID' Attribute ......................................4
3. Security Considerations .........................................4
4. IANA Considerations .............................................5
4.1. Object Identifier Registration .............................5
4.2. UUID Syntax Registration ...................................5
4.3. 'uuidMatch' Descriptor Registration ........................5
4.4. 'uuidOrderingMatch' Descriptor Registration ................5
4.5. 'entryUUID' Descriptor Registration ........................6
5. Acknowledgements ................................................6
6. References ......................................................6
6.1. Normative References .......................................6
6.2. Informative References .....................................7

1. Background and Intended Use

In X.500 Directory Services [X.501], such as those accessible using
the Lightweight Directory Access Protocol (LDAP) [RFC4510], an object
is identified by its distinguished name (DN). However, DNs are not
stable identifiers. That is, a new object may be identified by a DN
that previously identified another (now renamed or deleted) object.

A Universally Unique Identifier (UUID) is "an identifier unique
across both space and time, with respect to the space of all UUIDs"
[RFC4122]. UUIDs are used in a wide range of systems.

This document describes the 'entryUUID' operational attribute, which
holds the UUID assigned to the object by the server. Clients may use
this attribute to distinguish objects identified by a particular
distinguished name or to locate a particular object after renaming.

This document defines the UUID syntax, the 'uuidMatch' and
'uuidOrderingMatch' matching rules, and the 'entryUUID' attribute
type.

Schema definitions are provided using LDAP description formats
[RFC4512]. Definitions provided here are formatted (line wrapped)
for readability.

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RFC 4530 LDAP entryUUID June 2006

In this document, the key words "MUST", "MUST NOT", "REQUIRED",
"SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
and "OPTIONAL" are to be interpreted as described in BCP 14
[RFC2119].

2. UUID Schema Elements

2.1. UUID Syntax

A Universally Unique Identifier (UUID) [RFC4122] is a 16-octet (128-
bit) value that identifies an object. The ASN.1 [X.680] type UUID is
defined to represent UUIDs as follows:

UUID ::= OCTET STRING (SIZE(16))
-- constrained to an UUID [RFC4122]

In LDAP, UUID values are encoded using the [ASCII] character string
representation described in [RFC4122]. For example,
"597ae2f6-16a6-1027-98f4-d28b5365dc14".

The following is an LDAP syntax description suitable for publication
in subschema subentries.

( 1.3.6.1.1.16.1 DESC 'UUID' )

2.2. 'uuidMatch' Matching Rule

The 'uuidMatch' matching rule compares an asserted UUID with a stored
UUID for equality. Its semantics are the same as the
'octetStringMatch' [X.520][RFC4517] matching rule. The rule differs
from 'octetStringMatch' in that the assertion value is encoded using
the UUID string representation instead of the normal OCTET STRING
string representation.

The following is an LDAP matching rule description suitable for
publication in subschema subentries.

( 1.3.6.1.1.16.2 NAME 'uuidMatch'
SYNTAX 1.3.6.1.1.16.1 )

2.3. 'uuidOrderingMatch' Matching Rule

The 'uuidOrderingMatch' matching rule compares an asserted UUID with
a stored UUID for ordering. Its semantics are the same as the
'octetStringOrderingMatch' [X.520][RFC4517] matching rule. The rule
differs from 'octetStringOrderingMatch' in that the assertion value
is encoded using the UUID string representation instead of the normal
OCTET STRING string representation.

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RFC 4530 LDAP entryUUID June 2006

The following is an LDAP matching rule description suitable for
publication in subschema subentries.

( 1.3.6.1.1.16.3 NAME 'uuidOrderingMatch'
SYNTAX 1.3.6.1.1.16.1 )

Note that not all UUID variants have a defined ordering; and even
where it does, servers are not obligated to assign UUIDs in any
particular order. This matching rule is provided for completeness.

2.4. 'entryUUID' Attribute

The 'entryUUID' operational attribute provides the Universally Unique
Identifier (UUID) assigned to the entry.

The following is an LDAP attribute type description suitable for
publication in subschema subentries.

( 1.3.6.1.1.16.4 NAME 'entryUUID'
DESC 'UUID of the entry'
EQUALITY uuidMatch
ORDERING uuidOrderingMatch
SYNTAX 1.3.6.1.1.16.1
SINGLE-VALUE
NO-USER-MODIFICATION
USAGE directoryOperation )

Servers SHALL generate and assign a new UUID to each entry upon its
addition to the directory and provide that UUID as the value of the
'entryUUID' operational attribute. An entry's UUID is immutable.

UUID are to be generated in accordance with Section 4 of [RFC4122].
In particular, servers MUST ensure that each generated UUID is unique
in space and time.

3. Security Considerations

An entry's relative distinguish name (RDN) is composed from attribute
values of the entry, which are commonly descriptive of the object the
entry represents. Although deployers are encouraged to use naming
attributes whose values are widely disclosable [RFC4514], entries are
often named using information that cannot be disclosed to all
parties. As UUIDs do not contain any descriptive information of the
object they identify, UUIDs may be used to identify a particular
entry without disclosure of its contents.

General UUID security considerations [RFC4122] apply.

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RFC 4530 LDAP entryUUID June 2006

General LDAP security considerations [RFC4510] apply.

4. IANA Considerations

The IANA has registered the LDAP values [RFC4520] specified in this
document.

4.1. Object Identifier Registration

Subject: Request for LDAP OID Registration
Person & email address to contact for further information:
Kurt Zeilenga <[email protected]>
Specification: RFC 4530
Author/Change Controller: IESG
Comments:
Identifies the UUID schema elements

4.2. UUID Syntax Registration

Subject: Request for LDAP Syntax Registration
Object Identifier: 1.3.6.1.1.16.1
Description: UUID
Person & email address to contact for further information:
Kurt Zeilenga <[email protected]>
Specification: RFC 4530
Author/Change Controller: IESG
Comments:
Identifies the UUID syntax

4.3. 'uuidMatch' Descriptor Registration

Subject: Request for LDAP Descriptor Registration
Descriptor (short name): uuidMatch
Object Identifier: 1.3.6.1.1.16.2
Person & email address to contact for further information:
Kurt Zeilenga <[email protected]>
Usage: Matching Rule
Specification: RFC 4530
Author/Change Controller: IESG

4.4. 'uuidOrderingMatch' Descriptor Registration

Subject: Request for LDAP Descriptor Registration
Descriptor (short name): uuidOrderingMatch
Object Identifier: 1.3.6.1.1.16.3
Person & email address to contact for further information:
Kurt Zeilenga <[email protected]>
Usage: Matching Rule

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RFC 4530 LDAP entryUUID June 2006

Specification: RFC 4530
Author/Change Controller: IESG

4.5. 'entryUUID' Descriptor Registration

The IANA has registered the LDAP 'entryUUID' descriptor.

Subject: Request for LDAP Descriptor Registration
Descriptor (short name): entryUUID
Object Identifier: 1.3.6.1.1.16.4
Person & email address to contact for further information:
Kurt Zeilenga <[email protected]>
Usage: Attribute Type
Specification: RFC 4530
Author/Change Controller: IESG

5. Acknowledgements

This document is based upon discussions in the LDAP Update and
Duplication Protocols (LDUP) WG. Members of the LDAP Directorate
provided review.

6. References

6.1. Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.

[RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally
Unique IDentifier (UUID) URN Namespace", RFC 4122, July
2005.

[RFC4510] Zeilenga, K., Ed., "Lightweight Directory Access
Protocol (LDAP): Technical Specification Road Map", RFC
4510, June 2006.

[RFC4512] Zeilenga, K., "Lightweight Directory Access Protocol
(LDAP): Directory Information Models", RFC 4512, June
2006.

[RFC4517] Legg, S., Ed., "Lightweight Directory Access Protocol
(LDAP): Syntaxes and Matching Rules", RFC 4517, June
2006.

[ASCII] Coded Character Set--7-bit American Standard Code for
Information Interchange, ANSI X3.4-1986.

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RFC 4530 LDAP entryUUID June 2006

[X.501] International Telecommunication Union -
Telecommunication Standardization Sector, "The
Directory -- Models," X.501(1993) (also ISO/IEC 9594-
2:1994).

[X.520] International Telecommunication Union -
Telecommunication Standardization Sector, "The
Directory: Selected Attribute Types", X.520(1993) (also
ISO/IEC 9594-6:1994).

[X.680] International Telecommunication Union -
Telecommunication Standardization Sector, "Abstract
Syntax Notation One (ASN.1) - Specification of Basic
Notation", X.680(2002) (also ISO/IEC 8824-1:2002).

6.2. Informative References

[RFC4514] Zeilenga, K., Ed., "Lightweight Directory Access
Protocol (LDAP): String Representation of Distinguished
Names", RFC 4514, June 2006.

[RFC4520] Zeilenga, K., "Internet Assigned Numbers Authority
(IANA) Considerations for the Lightweight Directory
Access Protocol (LDAP)", BCP 64, RFC 4520, June 2006.

Author's Address

Kurt D. Zeilenga
OpenLDAP Foundation

EMail: [email protected]

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RFC 4530 LDAP entryUUID June 2006

Full Copyright Statement

Copyright (C) The Internet Society (2006).

This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
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