draft-legg-ldap-acm-admin-xx.txt [plain text]
INTERNET-DRAFT S. Legg
draft-legg-ldap-acm-admin-01.txt Adacel Technologies
Intended Category: Standards Track September 18, 2002
Access Control Administration in LDAP
Copyright (C) The Internet Society (2002). All Rights Reserved.
Status of this Memo
This document is an Internet-Draft and is in full conformance with
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1. Abstract
This document adapts the X.500 directory administrative model, as it
pertains to access control administration, for use by the Lightweight
Directory Access Protocol. The administrative model partitions the
Directory Information Tree for various aspects of directory data
administration, e.g. subschema, access control and collective
attributes. This document provides the particular definitions that
support access control administration, but does not define a
particular access control scheme.
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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 RFC 2119 [RFC2119].
2. Table of Contents
1. Abstract .................................................... 1
2. Table of Contents ........................................... 2
3. Introduction ................................................ 2
4. Access Control Administrative Areas ......................... 3
5. Access Control Scheme Indication ............................ 3
6. Access Control Information .................................. 4
7. Access Control Subentries ................................... 4
8. Applicable Access Control Information ....................... 5
9. Security Considerations ..................................... 5
10. Acknowledgements ........................................... 6
11. Normative References ....................................... 6
12. Informative References ..................................... 6
13. Copyright Notice ........................................... 7
14. Author's Address ........................................... 7
3. Introduction
This document adapts the X.500 directory administrative model [X501],
as it pertains to access control administration, for use by the
Lightweight Directory Access Protocol (LDAP) [RFC2251].
The administrative model [ADMIN] partitions the Directory Information
Tree (DIT) for various aspects of directory data administration, e.g.
subschema, access control and collective attributes. The parts of
the administrative model that apply to every aspect of directory data
administration are described in [ADMIN]. This document describes the
administrative framework for access control.
An access control scheme describes the means by which access to
directory information, and potentially to access rights themselves,
may be controlled. This document describes the framework for
employing access control schemes but does not define a particular
access control scheme. Two access control schemes known as Basic
Access Control and Simplified Access Control are defined by [BAC].
Other access control schemes MAY be defined by other documents.
Schema definitions are provided using LDAP description formats
[RFC2252]. Note that the LDAP descriptions have been rendered with
additional white-space and line breaks for the sake of readability.
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This document is derived from, and duplicates substantial portions
of, Sections 4 and 8 of [X501].
4. Access Control Administrative Areas
The specific administrative area [ADMIN] for access control is termed
an Access Control Specific Area (ACSA). The root of the ACSA is
termed an Access Control Specific Point (ACSP) and is represented in
the DIT by an administrative entry [ADMIN] which includes
accessControlSpecificArea as a value of its administrativeRole
operational attribute [SUBENTRY].
An ACSA MAY be partitioned into subtrees termed inner administrative
areas [ADMIN]. Each such inner area is termed an Access Control
Inner Area (ACIA). The root of the ACIA is termed an Access Control
Inner Point (ACIP) and is represented in the DIT by an administrative
entry which includes accessControlInnerArea as a value of its
administrativeRole operational attribute.
An administrative entry can never be both an ACSP and an ACIP. The
corresponding values can therefore never be present simultaneously in
the administrativeRole attribute.
Each entry necessarily falls within one and only one ACSA. Each such
entry may also fall within one or more ACIAs nested inside the ACSA
containing the entry.
An ACSP or ACIP has zero, one or more subentries that contain Access
Control Information (ACI).
5. Access Control Scheme Indication
The access control scheme (e.g. Basic Access Control [BAC]) in force
in an ACSA is indicated by the accessControlScheme operational
attribute contained in the administrative entry for the relevant
ACSP.
The LDAP description [RFC2252] for the accessControlScheme
operational attribute is:
( 2.5.24.1 NAME 'accessControlScheme'
EQUALITY objectIdentifierMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.38
SINGLE-VALUE USAGE directoryOperation )
An access control scheme conforming to the access control framework
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described in this document MUST define a distinct OBJECT IDENTIFIER
value to identify it through the accessControlScheme attribute.
Only administrative entries for ACSPs are permitted to contain an
accessControlScheme attribute. If the accessControlScheme attribute
is absent from a given ACSP, the access control scheme in force in
the corresponding ACSA, and its effect on operations, results and
errors, is implementation defined.
Any entry or subentry in an ACSA is permitted to contain ACI if and
only if such ACI is permitted by, and consistent with, the access
control scheme identified by the value of the accessControlScheme
attribute of the ACSP.
6. Access Control Information
There are three categories of Access Control Information (ACI):
entry, subentry and prescriptive.
Entry ACI applies to only the entry or subentry in which it appears,
and the contents thereof. Subject to the access control scheme, any
entry or subentry MAY hold entry ACI.
Subentry ACI applies to only the subentries of the administrative
entry in which it appears. Subject to the access control scheme, any
administrative entry, for any aspect of administration, MAY hold
subentry ACI.
Prescriptive ACI applies to all the entries within a subtree or
subtree refinement of an administrative area (either an ACSA or an
ACIA), as defined by the subtreeSpecification attribute of the
subentry in which it appears. Prescriptive ACI is only permitted in
subentries of an ACSP or ACIP. Prescriptive ACI in the subentries of
a particular administrative point never applies to the same or any
other subentry of that administrative point, but does apply to the
subentries of subordinate administrative points, where those
subentries are within the subtree or subtree refinement.
7. Access Control Subentries
Each subentry which contains prescriptive ACI MUST have
accessControlSubentry as a value of its objectClass attribute. Such
a subentry is called an access control subentry.
The LDAP description [RFC2252] for the accessControlSubentry
auxiliary object class is:
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( 2.5.17.1 NAME 'accessControlSubentry' AUXILIARY )
A subentry of this object class MUST contain at least one
prescriptive ACI attribute of a type consistent with the value of the
accessControlScheme attribute of the corresponding ACSP.
The subtree or subtree refinement for an access control subentry is
termed a Directory Access Control Domain (DACD). A DACD can contain
zero entries, and can encompass entries that have not yet been added
to the DIT, but does not extend beyond the scope of the ACSA or ACIA
with which it is associated.
Since a subtreeSpecification may define a subtree refinement, DACDs
within a given ACSA may arbitrarily overlap.
8. Applicable Access Control Information
Although particular items of ACI may specify attributes or values as
the protected items, ACI is logically associated with entries.
The ACI that is considered in access control decisions regarding an
entry includes:
(1) Entry ACI from that particular entry.
(2) Prescriptive ACI from access control subentries whose DACDs
contain the entry. Each of these access control subentries is
necessarily either a subordinate of the ACSP for the ACSA
containing the entry, or a subordinate of the ACIP for an ACIA
that contains the entry.
The ACI that is considered in access control decisions regarding a
subentry includes:
(1) Entry ACI from that particular subentry.
(2) Prescriptive ACI from access control subentries whose DACDs
contain the subentry, excluding those belonging to the same
administrative point as the subentry for which the decision is
being made.
(3) Subentry ACI from the administrative point associated with the
subentry.
9. Security Considerations
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This document defines a framework for employing an access control
scheme, i.e. the means by which access to directory information and
potentially to access rights themselves may be controlled, but does
not itself define any particular access control scheme. The degree
of protection provided, and any security risks, are determined by the
provisions of the access control schemes (defined elsewhere) making
use of this framework.
Security considerations that apply to directory administration in
general [ADMIN] also apply to access control administration.
10. Acknowledgements
This document is derived from, and duplicates substantial portions
of, Sections 4 and 8 of [X501].
11. 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.
[RFC2252] Wahl, M., Coulbeck, A., Howes, T. and S. Kille,
"Lightweight Directory Access Protocol (v3): Attribute
Syntax Definitions", RFC 2252, December 1997.
[ADMIN] Legg, S., "Directory Administrative Model in LDAP",
draft-legg-ldap-admin-xx.txt, a work in progress,
September 2002.
[SUBENTRY] Zeilenga, K. and S. Legg, "Subentries in LDAP",
draft-zeilenga-ldap-subentry-xx.txt, a work in progress,
August 2002.
12. Informative References
[BAC] Legg, S., "Basic and Simplified Access Control in LDAP",
draft-legg-ldap-acm-bac-xx.txt, a work in progress,
September 2002.
[COLLECT] Zeilenga, K., "Collective Attributes in LDAP",
draft-zeilenga-ldap-collective-xx.txt, a work in progress,
August 2002.
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[X501] ITU-T Recommendation X.501 (02/2001), Information
technology - Open Systems Interconnection - The Directory:
Models
13. Copyright Notice
Copyright (C) The Internet Society (2002). 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.
14. Author's Address
Steven Legg
Adacel Technologies Ltd.
405-409 Ferntree Gully Road
Mount Waverley, Victoria 3149
AUSTRALIA
Phone: +61 3 9451 2107
Fax: +61 3 9541 2121
EMail: steven.legg@adacel.com.au
15. Appendix A - Changes From Previous Drafts
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15.1 Changes in Draft 01
Section 4 has been extracted to become a separate Internet draft,
draft-legg-ldap-admin-00.txt. The subsections of Section 5 have
become the new Sections 4 to 8. Editorial changes have been made to
accommodate this split. No technical changes have been introduced.
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