INTERNET-DRAFT S. Legg draft-legg-ldap-binary-01.txt Adacel Technologies Intended Category: Standards Track 16 June 2004 Updates: RFC 2251bis Lightweight Directory Access Protocol (LDAP): The Binary Encoding Option Copyright (C) The Internet Society (2004). 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 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. This document is intended to be, after appropriate review and revision, submitted to the RFC Editor as a Standard Track document. Distribution of this document is unlimited. Technical discussion of this document should take place on the IETF LDAP Revision Working Group (LDAPbis) mailing list <ietf-ldapbis@openldap.org>. Please send editorial comments directly to the editor <steven.legg@adacel.com.au>. This Internet-Draft expires on 16 December 2004. Abstract Each attribute stored in a Lightweight Directory Access Protocol (LDAP) directory has a defined syntax (i.e., data type). A syntax Legg Expires 16 December 2004 [Page 1]
INTERNET-DRAFT LDAP: The Binary Encoding Option June 16, 2004 definition specifies how attribute values conforming to the syntax are normally represented when transferred in LDAP operations. This representation is referred to as the LDAP-specific encoding to distinguish it from other methods of encoding attribute values. This document defines an attribute option, the binary option, which can be used to specify that the associated attribute values are instead encoded according to the Basic Encoding Rules (BER) used by X.500 directories. Legg Expires 16 December 2004 [Page 2]
INTERNET-DRAFT LDAP: The Binary Encoding Option June 16, 2004 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions. . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. The binary Option. . . . . . . . . . . . . . . . . . . . . . . 4 4. Syntaxes Requiring Binary Transfer . . . . . . . . . . . . . . 4 5. Attributes Returned in a Search. . . . . . . . . . . . . . . . 5 6. All User Attributes. . . . . . . . . . . . . . . . . . . . . . 5 7. Conflicting Requests . . . . . . . . . . . . . . . . . . . . . 6 8. Security Considerations. . . . . . . . . . . . . . . . . . . . 6 9. IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 6 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 10.1. Normative References. . . . . . . . . . . . . . . . . . 6 10.2. Informative References. . . . . . . . . . . . . . . . . 7 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 7 Full Copyright Statement . . . . . . . . . . . . . . . . . . . . . 8 1. Introduction Each attribute stored in a Lightweight Directory Access Protocol (LDAP) directory [ROADMAP] has a defined syntax (i.e., data type) which constrains the structure and format of its values. The description of each syntax [SYNTAX] specifies how attribute or assertion values [MODELS] conforming to the syntax are normally represented when transferred in LDAP operations [PROT]. This representation is referred to as the LDAP-specific encoding to distinguish it from other methods of encoding attribute values. This document defines an attribute option, the binary option, which can be used in an attribute description [MODELS] in an LDAP operation to specify that the associated attribute values or assertion value are, or are requested to be, encoded according to the Basic Encoding Rules (BER) [BER] as used by X.500 [X500] directories, instead of the usual LDAP-specific encoding. The binary option was originally defined in RFC 2251 [RFC2251]. The LDAP technical specification [ROADMAP] has obsoleted the previously defined LDAP technical specification [RFC3377], which included RFC 2251. However the binary option was not included in the newer LDAP technical specification due to a lack of consistency in its implementation. This document reintroduces the binary option. However, except for the case of certain attribute syntaxes whose values are required to BER encoded, no attempt is made here to eliminate the known consistency problems. Rather the focus is on capturing current behaviours. A more thorough solution is left for a future specification. Legg Expires 16 December 2004 [Page 3]
INTERNET-DRAFT LDAP: The Binary Encoding Option June 16, 2004 2. Conventions 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, RFC 2119 [KEYWORD]. 3. The binary Option The binary option is indicated with the attribute option string "binary" in an attribute description. Note that, like all attribute options, the string representing the binary option is case insensitive. In terms of the protocol [PROT], the binary option specifies that the contents octets of the associated AttributeValue or AssertionValue OCTET STRING are a complete BER encoding of the relevant value. Where the binary option is present in an attribute description the associated attribute values or assertion value MUST be BER encoded. Note that it is possible for a syntax to be defined such that its LDAP-specific encoding is exactly the same as its BER encoding. The binary option is not a tagging option [MODELS] so the presence of the binary option does not specify an attribute subtype. An attribute description containing the binary option references exactly the same attribute as the same attribute description without the binary option. The supertype/subtype relationships of attributes with tagging options are not altered in any way by the presence or absence of the binary option. An attribute description SHALL be treated as unrecognized if it contains the binary option and the syntax of the attribute does not have an associated ASN.1 type [SYNTAX], or the BER encoding of that type is not supported. The presence or absence of the binary option only affects the transfer of attribute and assertion values in protocol; servers store any particular attribute value in a single format of their choosing. 4. Syntaxes Requiring Binary Transfer Certain syntaxes are required to be transferred in the BER encoded form. These syntaxes are said to have a binary transfer requirement. The Certificate, Certificate List, Certificate Pair and Supported Algorithm syntaxes [PKI] are examples of syntaxes with a binary transfer requirement. These syntaxes also have an additional requirement that the exact BER encoding must be preserved. Note that Legg Expires 16 December 2004 [Page 4]
INTERNET-DRAFT LDAP: The Binary Encoding Option June 16, 2004 this is a property of the syntaxes themselves, and not a property of the binary option. 5. Attributes Returned in a Search An LDAP search request [PROT] contains a list of the attributes (the requested attributes list) to be returned from each entry matching the search filter. An attribute description in the requested attributes list also implicitly requests all subtypes of the attribute type in the attribute description, whether through attribute subtyping or attribute tagging option subtyping [MODELS]. The requested attributes list MAY contain attribute descriptions with the binary option, but MUST NOT contain two attribute descriptions with the same attribute type and the same tagging options (even if only one of them has the binary option). The binary option in an attribute description in the requested attributes list implicitly applies to all the subtypes of the attribute type in the attribute description (however, see Section 7). Attributes of a syntax with the binary transfer requirement SHALL be returned in the binary form, i.e., with the binary option in the attribute description and the associated attribute values BER encoded, regardless of whether the binary option was present in the request (for the attribute or for one of its supertypes). Attributes of a syntax without the binary transfer requirement SHOULD be returned in the form explicitly requested. That is, if the attribute description in the requested attributes list contains the binary option then the corresponding attribute in the result SHOULD be in the binary form. If the attribute description in the request does not contain the binary option then the corresponding attribute in the result SHOULD NOT be in the binary form. A server MAY omit an attribute from the result if it does not support the requested encoding. Regardless of the encoding chosen, a particular attribute value is returned at most once. 6. All User Attributes If the list of attributes in a search request is empty, or contains the special attribute description string "*", then all user attributes are requested to be returned. Attributes of a syntax with the binary transfer requirement SHALL be returned in the binary form. Legg Expires 16 December 2004 [Page 5]
INTERNET-DRAFT LDAP: The Binary Encoding Option June 16, 2004 Attributes of a syntax without the binary transfer requirement and having a defined LDAP-specific encoding SHOULD NOT be returned in the binary form. Attributes of a syntax without the binary transfer requirement and without a defined LDAP-specific encoding may be returned in the binary form or omitted from the result. 7. Conflicting Requests A particular attribute could be explicitly requested by an attribute description and/or implicitly requested by the attribute descriptions of one or more of its supertypes, or by the special attribute description string "*". If the binary option is not present in all these attribute descriptions, nor absent in all these attribute descriptions, then the server is free to choose whether to return the attribute in the binary form. 8. Security Considerations When interpreting security-sensitive fields, and in particular fields used to grant or deny access, implementations MUST ensure that any matching rule comparisons are done on the underlying abstract value, regardless of the particular encoding used. 9. IANA Considerations The Internet Assigned Numbers Authority (IANA) is requested to update the LDAP attribute description option registry [BCP64] as indicated by the following template: Subject: Request for LDAP Attribute Description Option Registration Option Name: binary Family of Options: NO Person & email address to contact for further information: Steven Legg <steven.legg@adacel.com.au> Specification: RFC XXXX Author/Change Controller: IESG Comments: The existing registration for "binary" should be updated to refer to RFC XXXX. 10. References 10.1. Normative References [KEYWORD] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Legg Expires 16 December 2004 [Page 6]
INTERNET-DRAFT LDAP: The Binary Encoding Option June 16, 2004 [BCP64] Zeilenga, K., "Internet Assigned Numbers Authority (IANA) Considerations for the Lightweight Directory Access Protcol (LDAP)", BCP 64, RFC 3383, September 2002. [ROADMAP] Zeilenga, K., "Lightweight Directory Access Protocol (LDAP): Technical Specification Road Map", draft-ietf-ldapbis-roadmap-xx.txt, a work in progress, June 2004. [MODELS] Zeilenga, K., "LDAP: Directory Information Models", draft-ietf-ldapbis-models-xx.txt, a work in progress, June 2004. [PROT] Sermersheim, J., "LDAP: The Protocol", draft-ietf-ldapbis-protocol-xx.txt, a work in progress, May 2004. [SYNTAX] Legg, S. and K. Dally, "Lightweight Directory Access Protocol (LDAP): Syntaxes and Matching Rules", draft-ietf-ldapbis-syntaxes-xx.txt, a work in progress, May 2004. [PKI] Chadwick, D. and S. Legg, "Internet X.509 Public Key Infrastructure Additional LDAP Schema for PKIs and PMIs", draft-pkix-ldap-schema-xx.txt, a work in progress, April 2002. [BER] ITU-T Recommendation X.690 (07/02) | ISO/IEC 8825-1, Information Technology - ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER). 10.2. Informative References [RFC2251] Wahl, M., Howes, T. and S. Kille, "Lightweight Directory Access Protocol (v3)", RFC 2251, December 1997. [RFC3377] Hodges, J. and R. Morgan, "Lightweight Directory Access Protocol (v3): Technical Specification", RFC 3377, September 2002. [X500] ITU-T Recommendation X.500 (1993) | ISO/IEC 9594-1:1994, "Information Technology - Open Systems Interconnection - The Directory: Overview of concepts, models and services". Author's Address Legg Expires 16 December 2004 [Page 7]
INTERNET-DRAFT LDAP: The Binary Encoding Option June 16, 2004 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 Full Copyright Statement Copyright (C) The Internet Society (2004). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM 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. Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights 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; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat 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 implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Legg Expires 16 December 2004 [Page 8]
