





INTERNET-DRAFT                                                   S. Legg
draft-legg-ldap-acm-admin-02.txt                     Adacel Technologies
Intended Category: Standards Track                     February 25, 2003


                 Access Control Administration in LDAP

    Copyright (C) The Internet Society (2003). All Rights Reserved.

   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
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   Distribution of this document is unlimited.  Comments should be sent
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   This Internet-Draft expires on 25 August 2003.


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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2. Table of Contents

   1. Abstract ......................................................  1
   2. Table of Contents .............................................  2
   3. Introduction ..................................................  2
   4. Conventions ...................................................  2
   5. Access Control Administrative Areas ...........................  3
   6. Access Control Scheme Indication ..............................  3
   7. Access Control Information ....................................  4
   8. Access Control Subentries .....................................  4
   9. Applicable Access Control Information .........................  5
   10. Security Considerations ......................................  6
   11. Acknowledgements .............................................  6
   12. IANA Considerations ..........................................  6
   13. Normative References .........................................  7
   14. Informative References .......................................  7
   15. Copyright Notice .............................................  7
   16. Author's Address .............................................  8


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) [RFC3377].

   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.

   This document is derived from, and duplicates substantial portions
   of, Sections 4 and 8 of [X501].

4. Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and  "OPTIONAL" in this



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   document are to be interpreted as described in RFC 2119 [RFC2119].

   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.


5. 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).


6. 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



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          SINGLE-VALUE USAGE directoryOperation )

   An access control scheme conforming to the access control framework
   described in this document MUST define a distinct OBJECT IDENTIFIER
   value to identify it through the accessControlScheme attribute.
   Object Identifier Descriptors for access control scheme identifiers
   may be registered with IANA [RFC3383].

   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.


7. 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.


8. Access Control Subentries

   Each subentry which contains prescriptive ACI MUST have



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   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:

      ( 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.


9. 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.




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   (3) Subentry ACI from the administrative point associated with the
       subentry.


10. Security Considerations

   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.


11. Acknowledgements

   This document is derived from, and duplicates substantial portions
   of, Sections 4 and 8 of [X501].


12. IANA Considerations

   The Internet Assigned Numbers Authority (IANA) is requested to update
   the LDAP descriptors registry as indicated by the following
   templates:

      Subject: Request for LDAP Descriptor Registration
      Descriptor (short name): accessControlScheme
      Object Identifier: 2.5.24.1
      Person & email address to contact for further information:
        Steven Legg <steven.legg@adacel.com.au>
      Usage: attribute type
      Specification: RFC XXXX
      Author/Change Controller: IESG

      Subject: Request for LDAP Descriptor Registration
      Descriptor (short name): accessControlSubentry
      Object Identifier: 2.5.17.1
      Person & email address to contact for further information:
        Steven Legg <steven.legg@adacel.com.au>
      Usage: object class
      Specification: RFC XXXX
      Author/Change Controller: IESG




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13. Normative References

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

   [RFC2252]  Wahl, M., Coulbeck, A., Howes, T. and S. Kille,
              "Lightweight Directory Access Protocol (v3): Attribute
              Syntax Definitions", RFC 2252, December 1997.

   [RFC3377]  Hodges, J. and R. Morgan, "Lightweight Directory Access
              Protocol (v3): Technical Specification", RFC 3377,
              September 2002.

   [RFC3383]  Zeilenga, K., "Internet Assigned Numbers Authority (IANA
              Considerations for the Lightweight Directory Access
              Protocol (LDAP)", BCP 64, RFC 3383, September 2002.

   [ADMIN]    Legg, S., "Directory Administrative Model in LDAP",
              draft-legg-ldap-admin-xx.txt, a work in progress, February
              2003.

   [SUBENTRY] Zeilenga, K. and S. Legg, "Subentries in LDAP",
              draft-zeilenga-ldap-subentry-xx.txt, a work in progress,
              August 2002.


14. Informative References

   [BAC]      Legg, S., "Basic and Simplified Access Control in LDAP",
              draft-legg-ldap-acm-bac-xx.txt, a work in progress,
              February 2003.

   [COLLECT]  Zeilenga, K., "Collective Attributes in LDAP",
              draft-zeilenga-ldap-collective-xx.txt, a work in progress,
              August 2002.

   [X501]     ITU-T Recommendation X.501 (02/2001), Information
              technology - Open Systems Interconnection - The Directory:
              Models


15. Copyright Notice

      Copyright (C) The Internet Society (2003). 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



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   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.


16. Author's Address

   Steven Legg
   Adacel Technologies Ltd.
   250 Bay Street
   Brighton, Victoria 3186
   AUSTRALIA

   Phone: +61 3 8530 7710
     Fax: +61 3 8530 7888
   EMail: steven.legg@adacel.com.au


Appendix A - Changes From Previous Drafts

A.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.

A.2 Changes in Draft 02

   RFC 3377 replaces RFC 2251 as the reference for LDAP.




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   An IANA Considerations section has been added.


















































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