Commit 9b66997e authored by Kurt Zeilenga's avatar Kurt Zeilenga
Browse files

relevant I-Ds

parent cb6364f6
This diff is collapsed.
Internet Draft J. Sermersheim
Personal Submission R. Harrison
Intended Category: Standard Track Novell, Inc
Document: draft-sermersheim-ldap-chaining-02.txt Feb 2004
LDAP Control to Specify Chaining Behavior
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
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.
Distribution of this memo is unlimited. Technical discussion of this
document will take place on the IETF LDAP Extensions Working Group
mailing list <ldapext@ietf.org>. Editorial comments may be sent to
the author <jimse@novell.com>.
Abstract
This document describes a Lightweight Directory Access Protocol
(LDAP) request control that allows specification of chaining behavior
for LDAP operations. By using the control with various LDAP
operations, a directory client (DUA), or directory server (DSA)
specifies whether or not a DSA or secondary DSA chains operations to
other DSAs or returns referrals and/or search result references to
the client.
1. Introduction
Many directory servers have the ability through the use of various
mechanisms to participate in a distributed directory model. A
distributed directory is one where the DIT is distributed over
multiple DSAs. One operation completion mechanism used by DSAs in a
distributed directory is chaining. Chaining is defined in [X.518],
and is the act of one DSA communicating a directory operation that
Sermersheim, Harrison Internet-Draft - Exp. Aug 2004 Page 1
LDAP Control to Specify Chaining Behavior
originated from a DUA to another DSA in a distributed directory.
Contrast this with the act of passing referrals (4.1.11 of [RFC2251])
and SearchResultReferences (4.5.2 of [RFC2251]) back to the client.
Chaining may happen during the name resolution part of an operation
or during other parts of operations like search which apply to a
number of entries in a subtree.
This document does not attempt to define the distributed directory
model, nor does it attempt to define the manner in which DSAs chain
requests. This document defines a request control that the client can
use to specify whether parts of an operation should or should not be
chained.
2. Conventions
The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY"
used in this document carry the meanings described in [RFC2119].
The term chaining may apply to uni-chaining as well as multi-chaining
(see [X.518]) depending on the capabilities and configuration of the
DSAs.
3. The Control
Support for the control is advertised by the presence of its
controlType in the supportedControl attribute of a server's root DSE.
This control MAY be included in any LDAP request operation except
abandon, unbind, and StartTLS as part of the controls field of the
LDAPMessage, as defined in Section 4.1.12 of [RFC2251]:
The controlType is set to <IANA-ASSIGNED-OID.1>. The criticality MAY
be set to either TRUE or FALSE. The controlValue is an OCTET STRING,
whose value is the following ChainingBehavior type, BER encoded
following the rules in Section 5.1 of [RFC2251]:
ChainingBehavior ::= SEQUENCE {
resolveBehavior Behavior OPTIONAL,
continuationBehavior Behavior OPTIONAL }
Behavior :: = ENUMERATED {
chainingPreferred (0),
chainingRequired (1),
referralsPreferred (2),
referralsRequired (3) }
resolveBehavior instructs the DSA what to do when a referral is
encountered during the local name resolution part of an operation. If
this field is not specified, other policy dictates the DSA's
behavior.
Sermersheim, Harrison Internet-Draft - Exp. Aug 2004 Page 2
LDAP Control to Specify Chaining Behavior
continuationBehavior instructs the DSA what to do when a referral is
encountered after the name resolution part of an operation has
completed. This scenario occurs during search operations, and may
occur during yet to be defined future operations. If this field is
not specified, other policy dictates the DSA's behavior.
Behavior specifies whether the DSA should chain the operation or
return referrals when a target object is held by a remote service.
chainingPreferred indicates that the preference is that
chaining, rather than referrals, be used to provide the service.
When this value is set, the server attempts to chain the request
but if it can't it returns referrals.
chainingRequired indicates that chaining is to be used rather
than referrals to service the request. When this value is set,
the server MUST NOT return referrals. It either chains the
request or fails.
referralsPreferred indicates that the client wishes to receive
referrals rather than allow the server to chain the operation.
When this value is set, the server return referrals and search
references when possible, but may chain the operation otherwise.
referralsRequired indicates that chaining is prohibited. When
this value is set, the server MUST NOT chain the request to
other DSAs. Instead it returns referrals as necessary, or fails.
The following list assigns meanings to some of the result codes that
may occur due to this control being present:
- chainingRequired (IANA-ASSIGNED-1) Unable to process without
chaining.
- cannotChain (IANA-ASSIGNED-2) Unable to chain the request.
4. Notes to Implementors
<todo: add some>
4.1 Unbind and Abandon
Clients MUST NOT include the ChainingBehavior control with an Abandon
operation or an Unbind operation. Servers MUST ignore any chaining
control on the abandon and unbind requests. Servers that chain
operation are responsible to keep track of where an operation was
chained to for the purposes of unbind and abandon.
4.2 StartTLS
This operation cannot be chained because the TLS handshake protocol
does not allow man-in-the-middle attacks.
Sermersheim, Harrison Internet-Draft - Exp. Aug 2004 Page 3
LDAP Control to Specify Chaining Behavior
5. Relationship with other Extensions
This control MAY be used with other controls or with extended
operations. When it is used with other controls or with extended
operations not listed here, server behavior is undefined unless
otherwise specified.
5.1 Relationship with ManageDsaIT
When this control is used along with the ManageDsaIT control, the
resolveBehavior value is evaluated. If resolveBehavior is such that
chaining is allowed, the DSA is allowed to chain the operation as
necessary until the last RDN is found.
For example: DSA1 holds the naming context <dc=net> and a subordinate
reference to <dc=example,dc=net>, DSA2 holds the naming context
<dc=example,dc=net> and a subordinate reference to
<dc=hostc,dc=example,dc=net>.
A modify operation accompanied by the ManageDsaIT control alone is
sent to DSA1. The base object of the modify operation is set to
<dc=hostc,dc=example,dc=net>. Since DSA1 does not hold the
<dc=hostc,dc=example,dc=net> IT DSE, a referral is returned for
<dc=example,dc=net>.
Next, the same modify operation is accompanied by both the
ManageDsaIT and the ChainingBehavior control where the
ChainingBehavior.resolveBehavior is set to chainingPreferred. In this
case, DSA1 chains to DSA2 when it encounters <dc=example,dc=net> and
DSA2 continues the operation. Since DSA2 holds the IT DSE
<dc=hostc,dc=example,dc=net>, the resolve portion completes, and the
rest of the operation proceeds.
6. Security Considerations
Because this control directs a DSA to chain requests to other DSAs,
it may be used in a denial of service attack. Implementers should be
cognizant of this possibility.
This control may be used to allow access to hosts and portions of the
DIT not normally available to clients. Servers supporting this
control should provide sufficient policy to prevent unwanted
occurrences of this.
7. IANA Considerations
Registration of the following values is requested [RFC3383].
Sermersheim, Harrison Internet-Draft - Exp. Aug 2004 Page 4
LDAP Control to Specify Chaining Behavior
7.1. Object Identifiers
It is requested that IANA register upon Standards Action an LDAP
Object Identifier in identifying the protocol elements defined in
this technical specification. The following registration template is
suggested:
Subject: Request for LDAP OID Registration
Person & email address to contact for further information:
Jim Sermersheim
jimse@novell.com
Specification: RFCXXXX
Author/Change Controller: IESG
Comments:
One delegation will be made under the assigned OID:
IANA-ASSIGNED-OID.1 Chaining Behavior Request Control
7.2. LDAP Protocol Mechanism
It is requested that IANA register upon Standards Action the LDAP
protocol mechanism described in this document. The following
registration template is suggested:
Subject: Request for LDAP Protocol Mechanism Registration
Object Identifier: IANA-ASSIGNED-OID.1
Description: Chaining Behavior Request Control
Person & email address to contact for further information:
Jim Sermersheim
jimse@novell.com
Usage: Control
Specification: RFCXXXX
Author/Change Controller: IESG
Comments: none
7.3. LDAP Result Codes
It is requested that IANA register upon Standards Action the LDAP
result codes:
chainingRequired (IANA-ASSIGNED-1)
cannotChain (IANA-ASSIGNED-2)
The following registration template is suggested:
Subject: LDAP Result Code Registration
Person & email address to contact for further information:
Jim Sermersheim
jimse@novell.com
Result Code Name: chainingRequired
Result Code Name: cannotChain
Specification: RFCXXXX
Sermersheim, Harrison Internet-Draft - Exp. Aug 2004 Page 5
LDAP Control to Specify Chaining Behavior
Author/Change Controller: IESG
Comments: request consecutive result codes be assigned
8. Normative References
[X.518]
ITU-T Rec. X.511, "The Directory: Abstract Service Definition", 1993.
[RFC2119]
Bradner, Scott, "Key Words for use in RFCs to Indicate Requirement
Levels", Internet Draft, March 1997.
Available as RFC2119.
[RFC2251]
Wahl, M, S. Kille and T. Howes, "Lightweight Directory Access
Protocol (v3)", Internet Standard, December, 1997.
Available as RFC2251.
9. Authors' Addresses
Jim Sermersheim
Novell, Inc.
1800 South Novell Place
Provo, Utah 84606, USA
jimse@novell.com
+1 801 861-3088
Roger Harrison
Novell, Inc.
1800 South Novell Place
Provo, Utah 84606, USA
rharrison@novell.com
+1 801 861-2642
Sermersheim, Harrison Internet-Draft - Exp. Aug 2004 Page 6
LDAP Control to Specify Chaining Behavior
Intellectual Property Rights
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.
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.
Full Copyright Statement
Copyright (C) The Internet Society (2004). 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.
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 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.
Sermersheim, Harrison Internet-Draft - Exp. Aug 2004 Page 7
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>.
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 (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.
Zeilenga LDAP Read Entry Controls [Page 1]
INTERNET-DRAFT draft-zeilenga-ldap-readentry-01 26 October 2003
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.
Zeilenga LDAP Read Entry Controls [Page 2]
INTERNET-DRAFT draft-zeilenga-ldap-readentry-01 26 October 2003
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
Zeilenga LDAP Read Entry Controls [Page 3]
INTERNET-DRAFT draft-zeilenga-ldap-readentry-01 26 October 2003
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].