INTERNET-DRAFT Kurt D. Zeilenga Intended Category: Standard Track OpenLDAP Foundation Expires in six months 10 February 2005 The LDAP Assertion Control Status of this Memo This document is intended to be, after appropriate review and revision, submitted to the IESG for consideration 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 . Please send editorial comments directly to the author . By submitting this Internet-Draft, I accept the provisions of Section 4 of RFC 3667. By submitting this Internet-Draft, I certify that any applicable patent or other IPR claims of which I am aware have been disclosed, or will be disclosed, and any of which I become aware will be disclosed, in accordance with RFC 3668. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. 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Zeilenga LDAP Assertion Control [Page 1] INTERNET-DRAFT draft-zeilenga-ldap-assert-05 10 February 2005 Abstract This document defines the Lightweight Directory Access Protocol (LDAP) Assertion Control which allows a client to specify that a directory operation should only be processed if an assertion applied to the target entry of the operation is true. It can be used to construct "test and set" and "test and clear" and other conditional operations. 1. Overview This document defines the Lightweight Directory Access Protocol (LDAP) [Roadmap] assertion control. The assertion control allows the client to specify a condition which must be true for the operation to be processed normally. Otherwise the operation fails. For instance, the control can be used with the Modify operation [Protocol] to perform atomic "test and set" and "test and clear" operations. The control may be attached to any update operation to support conditional addition, deletion, modification, and renaming of the target object. The asserted condition is evaluated as an integral part the operation. The control may also be used with the search operation. Here the assertion is applied to the base object of the search before searching for objects matching the search scope and filter. The control may also be used with the compare operation. Here it extends the compare operation to allow a more complex assertion. 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 5.2 of [Protocol]. DSA stands for Directory System Agent (or 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. The Assertion Control Zeilenga LDAP Assertion Control [Page 2] INTERNET-DRAFT draft-zeilenga-ldap-assert-05 10 February 2005 The assertion control is an LDAP Control [Protocol] whose controlType is IANA-ASSIGNED-OID and controlValue is a BER-encoded Filter [Protocol, Section 4.5.1]. The criticality may be TRUE or FALSE. There is no corresponding response control. The control is appropriate for both LDAP interrogation and update operations [Protocol] including Add, Compare, Delete, Modify, ModifyDN (rename), and Search. It is inappropriate for Abandon, Bind nor Unbind, and Start TLS operations. When the control is attached to an LDAP request, the processing of the request is conditional on the evaluation of the Filter as applied against the target of the operation. If the Filter evaluates to TRUE, then the request is processed normally. If the Filter evaluates to FALSE or Undefined, then assertionFailed (IANA-ASSIGNED-CODE) resultCode is returned and no further processing is performed. For Add, Compare, and ModifyDN the target is indicated by the entry field in the request. For Modify, the target is indicated by the object field. For Delete, the target is indicated by the DelRequest type. For the Compare operation and all update operations, the evaluation of the assertion MUST be performed as an integral part of the operation. That is, the evaluation of the assertion and the normal processing of the operation SHALL be done as one atomic action. For search operation, the target is indicated by the baseObject field and the evaluation is done after "finding" but before "searching" [Protocol]. Hence, no entries or continuations references are returned if the assertion fails. Servers implementing this technical specification SHOULD publish the object identifier IANA-ASSIGNED-OID as a value of the 'supportedControl' attribute [Models] in their root DSE. A server MAY choose to advertise this extension only when the client is authorized to use it. Other documents may specify how this control applies to other LDAP operations. In doing so, they must state how the target entry is determined. 4. Security Considerations The filter may, like other components of the request, contain sensitive information. When so, this information should be appropriately protected. As with any general assertion mechanism, the mechanism can be used to Zeilenga LDAP Assertion Control [Page 3] INTERNET-DRAFT draft-zeilenga-ldap-assert-05 10 February 2005 determine directory content. Hence, this mechanism SHOULD be subject to appropriate access controls. Some assertions may be very complex, requiring significant time and resources to evaluate. Hence, this mechanism SHOULD be subject to appropriate administrative controls. Security considerations for the base operations [Protocol] extended by this control, as well as general LDAP security considerations [Roadmap], generally apply to implementation and use of this extension. 5. IANA Considerations 5.1. Object Identifier It is requested that IANA assign upon Standards Action an LDAP Object Identifier [BCP64bis] to identify the LDAP Assertion Control defined in this document. Subject: Request for LDAP Object Identifier Registration Person & email address to contact for further information: Kurt Zeilenga Specification: RFC XXXX Author/Change Controller: IESG Comments: Identifies the LDAP Assertion Control 5.2 LDAP Protocol Mechanism Registration of this protocol mechanism [BCP64bis] is requested. Subject: Request for LDAP Protocol Mechanism Registration Object Identifier: IANA-ASSIGNED-OID Description: Assertion Control Person & email address to contact for further information: Kurt Zeilenga Usage: Control Specification: RFC XXXX Author/Change Controller: IESG Comments: none 5.3 LDAP Result Code Assignment of an LDAP Result Code [BCP64bis] called 'assertionFailed' is requested. Zeilenga LDAP Assertion Control [Page 4] INTERNET-DRAFT draft-zeilenga-ldap-assert-05 10 February 2005 Subject: LDAP Result Code Registration Person & email address to contact for further information: Kurt Zeilenga Result Code Name: assertionFailed Specification: RFC XXXX Author/Change Controller: IESG Comments: none 6. Acknowledgments The assertion control concept is attributed to Morteza Ansari. 7. Author's Address Kurt D. Zeilenga OpenLDAP Foundation Email: Kurt@OpenLDAP.org 8. References [[Note to the RFC Editor: please replace the citation tags used in referencing Internet-Drafts with tags of the form RFCnnnn where possible.]] 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14 (also RFC 2119), March 1997. [Roadmap] Zeilenga, K. (editor), "LDAP: Technical Specification Road Map", draft-ietf-ldapbis-roadmap-xx.txt, a work in progress. [Protocol] Sermersheim, J. (editor), "LDAP: The Protocol", draft-ietf-ldapbis-protocol-xx.txt, a work in progress. [Models] Zeilenga, K. (editor), "LDAP: Directory Information Models", draft-ietf-ldapbis-models-xx.txt, a work in progress. 8.2. Informative References Zeilenga LDAP Assertion Control [Page 5] INTERNET-DRAFT draft-zeilenga-ldap-assert-05 10 February 2005 [BCP64bis] Zeilenga, K., "IANA Considerations for LDAP", draft-ietf-ldapbis-bcp64-xx.txt, a work in progress. 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