draft-zeilenga-ldap-readentry-xx.txt [plain text]
INTERNET-DRAFT Kurt D. Zeilenga
Intended Category: Standard Track OpenLDAP Foundation
Expires in six months 26 October 2003
LDAP Read Entry Controls
<draft-zeilenga-ldap-readentry-01.txt>
1. 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 Extensions mailing list
<ldapext@ietf.org>. Please send editorial comments directly to the
author <Kurt@OpenLDAP.org>.
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Copyright (C) The Internet Society (2003). All Rights Reserved.
Please see the Full Copyright section near the end of this document
for more information.
Abstract
This specification describes controls which can be attached to a
Lightweight Directory Access Protocol (LDAP) update request to obtain
copies of the target entry before and/or after the requested update is
applied.
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1. Background and Intent of Use
This specification describes controls [RFC2251] which can be attached
to Lightweight Directory Access Protocol (LDAP) [RFC3377] update
requests to request and return copies of the target entry. One
request control, called the Pre-Read request control, indicates that a
copy of the entry before application of update is to be returned.
Another control, called the Post-Read request control, indicates that
a copy of the entry after application of the update is to be returned.
Each request control has a corresponding response control used to
return the entry.
The functionality offered by these controls is based upon similar
functionality in the X.500 Directory Access Protocol (DAP) [X.511].
The Pre-Read controls may be used to obtain replaced or deleted values
of modified attributes or a copy of the entry being deleted.
The Post-Read controls may be used to obtain values of operational
attributes, such as the 'entryUUID' [EntryUUID] and 'modifytimestamp'
[RFC2252] attributes, updated by the server as part of the update
operation.
2. Terminology
Protocol elements are described using ASN.1 [X.680] with implicit
tags. The term "BER-encoded" means the element is to be encoded using
the Basic Encoding Rules [X.690] under the restrictions detailed in
Section 5.1 of [RFC2251].
DN stands for Distinguished Name.
DSA stands for Directory System Agent (i.e., a directory server).
DSE stands for DSA-specific Entry.
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].
3. Read Entry Controls
3.1. The Pre-Read Controls
The Pre-Read request and response controls are identified by the
IANA-ASSIGNED-OID.1 object identifier. Servers implementing these
controls SHOULD publish IANA-ASSIGNED-OID.1 as a value of the
'supportedControl' [RFC2252] in their root DSE.
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The Pre-Read request control is an LDAP Control [RFC2251] whose
controlType is IANA-ASSIGNED-OID.1 and controlValue is a BER-encoded
AttributeDescriptionList [RFC2251]. The criticality may be TRUE or
FALSE. This control is appropriate for the modifyRequest, delRequest,
and modDNRequest LDAP messages.
The corresponding response control is a LDAP Control whose controlType
is IANA-ASSIGNED-OID.1 and the controlValue, an OCTET STRING, contains
a BER-encoded SearchResultEntry. The criticality may be TRUE or
FALSE. This control is appropriate for the modifyResponse,
delResponse, and modDNResponse LDAP messages with a resultCode of
success (0).
When the request control is attached to an appropriate update LDAP
request, the control requests the return of a copy of target entry
prior to the application of the update. The AttributeDescriptionList
indicates which attributes are requested to appear in the copy. There
are two special AttributeDescriptions which may be included in the
list, "*" and "+". "*" requests all user attributes. "+" requests
all operational attributes. If the list is empty, all user attributes
are requested. If the list contains an unrecognized attribute type,
that type is simply ignored. If all attribute types are unrecognized,
no attributes are to be returned. The server is to return a
SearchResultEntry containing, subject to access controls and other
constraints, values of the requested attributes.
The normal processing of the update operation and the processing of
this control MUST be performed as one atomic action isolated from
other update operations.
If the update operation fails, no response control is provided.
3.2. The Post-Read Controls
The Post-Read request and response controls are identified by the
IANA-ASSIGNED-OID.2 object identifier. Servers implementing these
controls SHOULD publish IANA-ASSIGNED-OID.2 as a value of the
'supportedControl' [RFC2252] in their root DSE.
The Post-Read request control is an LDAP Control [RFC2251] whose
controlType is IANA-ASSIGNED-OID.2 and controlValue, an OCTET STRING,
contains a BER-encoded AttributeDescriptionList [RFC2251]. The
criticality may be TRUE or FALSE. This control is appropriate for the
addRequest, modifyRequest, and modDNRequest LDAP messages.
The corresponding response control is a LDAP Control whose controlType
is IANA-ASSIGNED-OID.2 and controlValue is a BER-encoded
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SearchResultEntry. The criticality may be TRUE or FALSE. This
control is appropriate for the addResponse, modifyResponse, and
modDNResponse LDAP messages with a resultCode of success (0).
When the request control is attached to an appropriate update LDAP
request, the control requests the return of a copy of target entry
after the application of the update. The AttributeDescriptionList
indicates which attributes are requested to appear in the copy. There
are two special AttributeDescriptions which may be included in the
list, "*" and "+". "*" requests all user attributes. "+" requests
all operational attributes. If the list is empty, all user attributes
are requested. If the list contains an unrecognized attribute type,
that type is simply ignored. If all attribute types are unrecognized,
no attributes are to be returned. The server is to return a
SearchResultEntry containing, subject to access controls and other
constraints, values of the requested attributes.
The normal processing of the update operation and the processing of
this control MUST be performed as one atomic action isolated from
other update operations.
If the update operation fails, no response control is provided.
4. Interaction with other controls
The Pre- and Post-Read controls may be combined with each other and/or
with a variety of other controls. When combined with the assertion
control [ASSERT], the manageDsaIT control [RFC3296], and/or the proxy
authorization control [PROXYAUTH], the semantics of each control
included in the combination apply. The Pre- and Post-Read controls
may be combined with other controls as detailed in other technical
specifications.
5. Security Considerations
The controls defined in this document extend update operations to
support read capabilities. Servers MUST ensure that the client is
authorized both for reading of the information provided in this
control in addition to ensuring the client is authorized to perform
the requested directory update.
Implementors of this (or any) LDAP extension should be familiar with
general LDAP security considerations [RFC3377].
6. IANA Considerations
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Registration of the following protocol values [RFC3383] is requested.
6.1. Object Identifier
It is requested that IANA register an LDAP Object Identifier to
identify LDAP protocol elements defined in this document.
Subject: Request for LDAP Object Identifier Registration
Person & email address to contact for further information:
Kurt Zeilenga <kurt@OpenLDAP.org>
Specification: RFC XXXX
Author/Change Controller: IESG
Comments:
Identifies the LDAP Read Entry Controls
6.2. LDAP Protocol Mechanisms
It is requested that IANA register the LDAP Protocol Mechanism
described in this document.
Subject: Request for LDAP Protocol Mechanism Registration
Object Identifier: IANA-ASSIGNED-OID.1
Description: LDAP Pre-read Control
Person & email address to contact for further information:
Kurt Zeilenga <kurt@openldap.org>
Usage: Control
Specification: RFC XXXX
Author/Change Controller: IESG
Comments: none
in 2
Subject: Request for LDAP Protocol Mechanism Registration
Object Identifier: IANA-ASSIGNED-OID.2
Description: LDAP Post-read Control
Person & email address to contact for further information:
Kurt Zeilenga <kurt@openldap.org>
Usage: Control
Specification: RFC XXXX
Author/Change Controller: IESG
Comments: none
in 2
7. Acknowledgment
The LDAP Pre- and Post-Read controls are modeled after similar
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capabilities offered in the DAP [X.511].
8. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14 (also RFC 2119), March 1997.
[RFC2251] Wahl, M., T. Howes and S. Kille, "Lightweight Directory
Access Protocol (v3)", RFC 2251, December 1997.
[RFC2252] Wahl, M., A. Coulbeck, T. Howes, and S. Kille,
"Lightweight Directory Access Protocol (v3): Attribute
Syntax Definitions", RFC 2252, December 1997.
[RFC2830] Hodges, J., R. Morgan, and M. Wahl, "Lightweight
Directory Access Protocol (v3): Extension for Transport
Layer Security", RFC 2830, May 2000.
[RFC3296] Zeilenga, K., "Named Subordinate References in
Lightweight Directory Access Protocol (LDAP)
Directories", RFC 3296, July 2002.
[RFC3377] Hodges, J. and R. Morgan, "Lightweight Directory Access
Protocol (v3): Technical Specification", RFC 3377,
September 2002.
[X.680] International Telecommunication Union -
Telecommunication Standardization Sector, "Abstract
Syntax Notation One (ASN.1) - Specification of Basic
Notation", X.680(1997) (also ISO/IEC 8824-1:1998).
[X.690] International Telecommunication Union -
Telecommunication Standardization Sector, "Specification
of ASN.1 encoding rules: Basic Encoding Rules (BER),
Canonical Encoding Rules (CER), and Distinguished
Encoding Rules (DER)", X.690(1997) (also ISO/IEC
8825-1:1998).
[PROXYAUTH] Weltman, R., "LDAP Proxy Authentication Control", draft-
weltman-ldapv3-proxy-xx.txt, a work in progress.
[ASSERT] Zeilenga, K., "LDAP Assertion Control",
draft-zeilenga-ldap-assert-xx.txt, a work in progress.
9. Informative References
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[RFC3383] Zeilenga, K., "IANA Considerations for LDAP", BCP 64
(also RFC 3383), September 2002.
[X.511] International Telecommunication Union -
Telecommunication Standardization Sector, "The
Directory: Abstract Service Definition", X.511(1993).
[EntryUUID] Zeilenga, K., "The LDAP EntryUUID Operational
Attribute", draft-zeilenga-ldap-uuid-xx.txt, a work in
progress.
10. Author's Address
Kurt D. Zeilenga
OpenLDAP Foundation
<Kurt@OpenLDAP.org>
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Copyright (C) The Internet Society (2003). All Rights Reserved.
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