--- 1/draft-ietf-ldapbis-protocol-28.txt 2006-02-05 00:12:33.000000000 +0100 +++ 2/draft-ietf-ldapbis-protocol-29.txt 2006-02-05 00:12:33.000000000 +0100 @@ -1,13 +1,14 @@ + Internet-Draft Editor: J. Sermersheim Intended Category: Standard Track Novell, Inc -Document: draft-ietf-ldapbis-protocol-28.txt Nov 2004 +Document: draft-ietf-ldapbis-protocol-29.txt Feb 2005 Obsoletes: RFCs 2251, 2830, 3771 LDAP: The Protocol Status of this Memo This document is an Internet-Draft and is subject to all provisions of section 3 of RFC 3667. By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of @@ -47,70 +48,69 @@ (LDAP). LDAP provides access to distributed directory services that act in accordance with X.500 data and service models. These protocol elements are based on those described in the X.500 Directory Access Protocol (DAP). Lightweight Directory Access Protocol Version 3 Table of Contents 1. Introduction....................................................3 - 1.1. Relationship to Obsolete Specifications.......................3 + 1.1. Relationship to Other LDAP Specifications.....................3 2. Conventions.....................................................3 3. Protocol Model..................................................4 - 3.1 Operation and LDAP Exchange Relationship.......................4 + 3.1 Operation and LDAP Message Layer Relationship..................4 4. Elements of Protocol............................................5 4.1. Common Elements...............................................5 4.1.1. Message Envelope............................................5 4.1.2. String Types................................................7 4.1.3. Distinguished Name and Relative Distinguished Name..........7 4.1.4. Attribute Descriptions......................................8 4.1.5. Attribute Value.............................................8 4.1.6. Attribute Value Assertion...................................8 4.1.7. Attribute and PartialAttribute..............................9 4.1.8. Matching Rule Identifier....................................9 4.1.9. Result Message..............................................9 4.1.10. Referral..................................................11 4.1.11. Controls..................................................12 4.2. Bind Operation...............................................14 4.3. Unbind Operation.............................................17 4.4. Unsolicited Notification.....................................17 - 4.5. Search Operation.............................................18 4.6. Modify Operation.............................................28 4.7. Add Operation................................................29 4.8. Delete Operation.............................................30 4.9. Modify DN Operation..........................................31 4.10. Compare Operation...........................................32 4.11. Abandon Operation...........................................33 4.12. Extended Operation..........................................34 4.13. IntermediateResponse Message................................35 4.13.1. Usage with LDAP ExtendedRequest and ExtendedResponse......36 4.13.2. Usage with LDAP Request Controls..........................36 4.14. StartTLS Operation..........................................36 5. Protocol Encoding, Connection, and Transfer....................38 - 5.2. Protocol Encoding............................................39 - 5.3. Transmission Control Protocol (TCP)..........................39 + 5.1. Protocol Encoding............................................38 + 5.2. Transmission Control Protocol (TCP)..........................39 + 5.3. Termination of the LDAP session..............................39 6. Security Considerations........................................39 7. Acknowledgements...............................................41 8. Normative References...........................................41 9. Informative References.........................................43 10. IANA Considerations...........................................43 11. Editor's Address..............................................43 - Appendix A - LDAP Result Codes....................................44 - A.1 Non-Error Result Codes........................................44 - A.2 Result Codes..................................................44 - Appendix B - Complete ASN.1 Definition............................49 - Appendix C - Changes..............................................55 - C.1 Changes made to RFC 2251:.....................................55 - C.2 Changes made to RFC 2830:.....................................60 - C.3 Changes made to RFC 3771:.....................................61 - + Appendix A - LDAP Result Codes....................................45 + A.1 Non-Error Result Codes........................................45 + A.2 Result Codes..................................................45 + Appendix B - Complete ASN.1 Definition............................50 + Appendix C - Changes..............................................56 + C.1 Changes made to RFC 2251:.....................................56 + C.2 Changes made to RFC 2830:.....................................61 + C.3 Changes made to RFC 3771:.....................................62 Lightweight Directory Access Protocol Version 3 1. Introduction The Directory is "a collection of open systems cooperating to provide directory services" [X.500]. A directory user, which may be a human or other entity, accesses the Directory through a client (or Directory User Agent (DUA)). The client, on behalf of the directory user, interacts with one or more servers (or Directory System Agents (DSA)). Clients interact with servers using a directory access @@ -296,25 +294,26 @@ The function of the LDAPMessage is to provide an envelope containing common fields required in all protocol exchanges. At this time the only common fields are the messageID and the controls. If the server receives a PDU from the client in which the LDAPMessage SEQUENCE tag cannot be recognized, the messageID cannot be parsed, the tag of the protocolOp is not recognized as a request, or the encoding structures or lengths of data fields are found to be incorrect, then the server SHOULD return the Notice of Disconnection described in Section 4.4.1, with the resultCode set to protocolError, - and MUST immediately close the transport connection. + and MUST immediately terminate the LDAP session as described in + Section 5.3. In other cases where the client or server cannot parse a PDU, it - SHOULD abruptly close the transport connection where further - communication (including providing notice) would be + SHOULD abruptly terminate the LDAP session (Section 5.3) where + further communication (including providing notice) would be pernicious. Otherwise, server implementations MUST return an appropriate response to the request, with the resultCode set to protocolError. 4.1.1.1. Message ID All LDAPMessage envelopes encapsulating responses contain the messageID value of the corresponding request LDAPMessage. The message ID of a request MUST have a non-zero value different from @@ -473,26 +469,25 @@ request. LDAPResult ::= SEQUENCE { resultCode ENUMERATED { success (0), operationsError (1), protocolError (2), timeLimitExceeded (3), sizeLimitExceeded (4), compareFalse (5), - Lightweight Directory Access Protocol Version 3 compareTrue (6), authMethodNotSupported (7), - strongAuthRequired (8), + strongerAuthRequired (8), -- 9 reserved -- referral (10), adminLimitExceeded (11), unavailableCriticalExtension (12), confidentialityRequired (13), saslBindInProgress (14), noSuchAttribute (16), undefinedAttributeType (17), inappropriateMatching (18), constraintViolation (19), @@ -584,38 +578,36 @@ Referral ::= SEQUENCE SIZE (1..MAX) OF uri URI URI ::= LDAPString -- limited to characters permitted in -- URIs If the client wishes to progress the operation, it contacts one of the supported services found in the referral. If multiple URIs are present, the client assumes that any supported URI may be used to progress the operation. - Protocol peers that follow referrals MUST ensure that they do not - loop between servers. They MUST NOT repeatedly contact the same - + Clients that follow referrals MUST ensure that they do not loop + between servers. They MUST NOT repeatedly contact the same server for Lightweight Directory Access Protocol Version 3 - server for the same request with the same parameters. Some - implementations use a counter that is incremented each time referral - handling occurs for an operation, and these kinds of implementations - MUST be able to handle at least ten nested referrals between the root - and a leaf entry. + the same request with the same parameters. Some clients use a counter + that is incremented each time referral handling occurs for an + operation, and these kinds of clients MUST be able to handle at least + ten nested referrals while progressing the operation. A URI for a server implementing LDAP and accessible via [TCP]/[IP] (v4 or v6) is written as an LDAP URL according to [LDAPURL]. Referral values which are LDAP URLs follow these rules: - - If an alias was dereferenced, the part of the URL MUST be - present, with the new target object name. + - If an alias was dereferenced, the part of the LDAP URL MUST + be present, with the new target object name. - It is RECOMMENDED that the part be present to avoid ambiguity. - If the part is present, the client uses this name in its next request to progress the operation, and if it is not present the client uses the same name as in the original request. - Some servers (e.g. participating in distributed indexing) may provide a different filter in a URL of a referral for a Search @@ -633,22 +625,23 @@ is used by the client to progress the operation. - Other aspects of the new request may be the same as or different from the request which generated the referral. Other kinds of URIs may be returned. The syntax and semantics of such URIs is left to future specifications. Clients may ignore URIs that they do not support. UTF-8 encoded characters appearing in the string representation of a - DN, search filter, or other fields may not be legal for URLs (e.g. - spaces) and MUST be escaped using the % method in [URI]. + DN, search filter, or other fields of the referral value may not be + legal for URIs (e.g. spaces) and MUST be escaped using the % method + in [URI]. 4.1.11. Controls Controls provide a mechanism whereby the semantics and arguments of existing LDAP operations may be extended. One or more controls may be attached to a single LDAP message. A control only affects the semantics of the message it is attached to. Lightweight Directory Access Protocol Version 3 @@ -806,22 +798,21 @@ BindResponse to indicate the status of authentication. After sending a BindRequest, clients MUST NOT send further LDAP PDUs until receiving the BindResponse. Similarly, servers SHOULD NOT process or respond to requests received while processing a BindRequest. If the client did not bind before sending a request and receives an operationsError to that request, it may then send a BindRequest. If this also fails or the client chooses not to bind on the existing - LDAP session, it may close the transport connection, reopen it and - + LDAP session, it may terminate the LDAP session, re-establish it and Lightweight Directory Access Protocol Version 3 begin again by first sending a PDU with a BindRequest. This will aid in interoperating with servers implementing other versions of LDAP. Clients may send multiple Bind requests to change the authentication and/or security associations or to complete a multi-stage Bind process. Authentication from earlier binds is subsequently ignored. For some SASL authentication mechanisms, it may be necessary for the @@ -855,28 +846,27 @@ set in the BindResponse. For BindResponse, the protocolError result code may be used to indicate that the version number supplied by the client is unsupported. If the client receives a BindResponse where the resultCode is set to protocolError, it is to assume that the server does not support this version of LDAP. While the client may be able proceed with another version of this protocol (this may or may not require closing and re- establishing the transport connection), how to proceed with another version of this protocol is beyond the scope of this document. - Clients which are unable or unwilling to proceed SHOULD close the - transport connection. + Clients which are unable or unwilling to proceed SHOULD terminate the + LDAP session. The serverSaslCreds field is used as part of a SASL-defined bind mechanism to allow the client to authenticate the server to which it is communicating, or to perform "challenge-response" authentication. If the client bound with the simple choice, or the SASL mechanism - Lightweight Directory Access Protocol Version 3 does not require the server to return information to the client, then this field SHALL NOT be included in the BindResponse. 4.3. Unbind Operation The function of the Unbind operation is to terminate an LDAP session. The Unbind operation is not the antithesis of the Bind operation as the name implies. The naming of these operations are historical. The @@ -880,29 +870,24 @@ The function of the Unbind operation is to terminate an LDAP session. The Unbind operation is not the antithesis of the Bind operation as the name implies. The naming of these operations are historical. The Unbind operation should be thought of as the "quit" operation. The Unbind operation is defined as follows: UnbindRequest ::= [APPLICATION 2] NULL The client, upon transmission of the UnbindRequest, and the server, - upon receipt of the UnbindRequest are to close the LDAP session as - follows: - - - cease exchanges at the LDAP message layer, - - close the SASL layer (if installed), - - close the TLS layer (if installed), and - - close the transport connection. + upon receipt of the UnbindRequest are to gracefully terminate the + LDAP session as described in Section 5.3. - Uncompleted operations are handled as specified in Section 5.1. + Uncompleted operations are handled as specified in Section 3.1. 4.4. Unsolicited Notification An unsolicited notification is an LDAPMessage sent from the server to the client which is not in response to any LDAPMessage received by the server. It is used to signal an extraordinary condition in the server or in the LDAP session between the client and the server. The notification is of an advisory nature, and the server will not expect any response to be returned from the client. @@ -917,44 +902,42 @@ consists of: - the OBJECT IDENTIFIER assigned to the notification (to be specified in the responseName, - the format of the contents of the responseValue (if any), - the circumstances which will cause the notification to be sent, and - Lightweight Directory Access Protocol Version 3 - - the semantics of the message. 4.4.1. Notice of Disconnection + Lightweight Directory Access Protocol Version 3 This notification may be used by the server to advise the client that - the server is about to close the transport connection on its own + the server is about to terminate the LDAP session on its own initiative. This notification is intended to assist clients in distinguishing between an exceptional server condition and a transient network failure. Note that this notification is not a response to an Unbind requested by the client. Uncompleted operations - are handled as specified in Section 5.1. + are handled as specified in Section 3.1. The responseName is 1.3.6.1.4.1.1466.20036, the responseValue field is absent, and the resultCode is used to indicate the reason for the - disconnection. When the strongAuthRequired resultCode is returned + disconnection. When the strongerAuthRequired resultCode is returned with this message, it indicates that the server has detected that an established security association between the client and server has unexpectedly failed or been compromised. - Upon transmission of the Notice of Disconnection, the server MUST - cease transmission of messages to the client, and MUST close the - transport connection. + Upon transmission of the Notice of Disconnection, the server + gracefully terminates the LDAP session as described in Section 5.3. 4.5. Search Operation The Search operation is used to request a server to return, subject to access controls and other restrictions, a set of entries matching a complex search criterion. This can be used to read attributes from a single entry, from entries immediately subordinate to a particular entry, or a whole subtree of entries. 4.5.1. Search Request @@ -970,28 +953,26 @@ ... }, derefAliases ENUMERATED { neverDerefAliases (0), derefInSearching (1), derefFindingBaseObj (2), derefAlways (3) }, sizeLimit INTEGER (0 .. maxInt), timeLimit INTEGER (0 .. maxInt), typesOnly BOOLEAN, filter Filter, - - Lightweight Directory Access Protocol Version 3 - attributes AttributeSelection } AttributeSelection ::= SEQUENCE OF selector LDAPString -- The LDAPString is constrained to - -- below + -- in Section 4.5.1.7 + Lightweight Directory Access Protocol Version 3 Filter ::= CHOICE { and [0] SET SIZE (1..MAX) OF filter Filter, or [1] SET SIZE (1..MAX) OF filter Filter, not [2] Filter, equalityMatch [3] AttributeValueAssertion, substrings [4] SubstringFilter, greaterOrEqual [5] AttributeValueAssertion, lessOrEqual [6] AttributeValueAssertion, present [7] AttributeDescription, @@ -1023,81 +1004,84 @@ semantics as the X.500 Search operation. 4.5.1.1 SearchRequest.baseObject The name of the base object entry (or possibly the root) relative to which the Search is to be performed. 4.5.1.2 SearchRequest.scope Specifies the scope of the Search to be performed. The semantics (as - described in [X.511]) of the possible values of this field are: - - Lightweight Directory Access Protocol Version 3 + described in [X.511]) of the defined values of this field are: baseObject: The scope is constrained to the entry named by baseObject. singleLevel: The scope is constrained to the immediate subordinates of the entry named by baseObject. + Lightweight Directory Access Protocol Version 3 + wholeSubtree: the scope is constrained to the entry named by the baseObject, and all its subordinates. 4.5.1.3 SearchRequest.derefAliases - An indicator as to how alias entries (as defined in [Models]) are to - be handled in searching. The semantics of the defined values of this - field are: + An indicator as to whether or not alias entries (as defined in + [Models]) are to be dereferenced during stages of the Search + operation. + + The act of dereferencing an alias includes recursively dereferencing + aliases which refer to aliases. + + Servers MUST detect looping while dereferencing aliases in order to + prevent denial of service attacks of this nature. + + The semantics of the defined values of this field are: neverDerefAliases: Do not dereference aliases in searching or in locating the base object of the Search. derefInSearching: While searching subordinates of the base object, - dereference any alias within the search scope (the act of - dereferencing an alias includes recursively dereferencing aliases - which refer to aliases). Dereferenced objects become the vertices - of further search scopes where the Search operation continues. If - the search scope is wholeSubtree, the Search continues in the - subtree(s) of any dereferenced object. If the search scope is - singleLevel, the search is applied to any dereferenced objects, - and is not applied to their subordinates. Servers SHOULD eliminate - duplicate entries that arise due to alias dereferencing while - searching. + dereference any alias within the search scope. Dereferenced + objects become the vertices of further search scopes where the + Search operation is also applied. If the search scope is + wholeSubtree, the Search continues in the subtree(s) of any + dereferenced object. If the search scope is singleLevel, the + search is applied to any dereferenced objects, and is not applied + to their subordinates. Servers SHOULD eliminate duplicate entries + that arise due to alias dereferencing while searching. derefFindingBaseObj: Dereference aliases in locating the base object of the Search, but not when searching subordinates of the base object. derefAlways: Dereference aliases both in searching and in locating the base object of the Search. - Servers MUST detect looping while dereferencing aliases in order to - prevent denial of service attacks of this nature. - 4.5.1.4 SearchRequest.sizeLimit A size limit that restricts the maximum number of entries to be returned as a result of the Search. A value of zero in this field indicates that no client-requested size limit restrictions are in effect for the Search. Servers may also enforce a maximum number of entries to return. 4.5.1.5 SearchRequest.timeLimit - Lightweight Directory Access Protocol Version 3 - A time limit that restricts the maximum time (in seconds) allowed for a Search. A value of zero in this field indicates that no client- requested time limit restrictions are in effect for the Search. Servers may also enforce a maximum time limit for the Search. + Lightweight Directory Access Protocol Version 3 + 4.5.1.6 SearchRequest.typesOnly An indicator as to whether Search results are to contain both attribute descriptions and values, or just attribute descriptions. Setting this field to TRUE causes only attribute descriptions (no values) to be returned. Setting this field to FALSE causes both attribute descriptions and values to be returned. 4.5.1.7 SearchRequest.filter @@ -1131,27 +1115,27 @@ able to determine whether the assertion value matches an entry. Examples include: - An attribute description in an equalityMatch, substrings, greaterOrEqual, lessOrEqual, approxMatch or extensibleMatch filter is not recognized by the server. - The attribute type does not define the appropriate matching rule. - Lightweight Directory Access Protocol Version 3 - - A MatchingRuleId in the extensibleMatch is not recognized by the server or is not valid for the attribute type. - The type of filtering requested is not implemented. + Lightweight Directory Access Protocol Version 3 + - The assertion value is invalid. For example, if a server did not recognize the attribute type shoeSize, a filter of (shoeSize=*) would evaluate to FALSE, and the filters (shoeSize=12), (shoeSize>=12) and (shoeSize<=12) would each evaluate to Undefined. Servers MUST NOT return errors if attribute descriptions or matching rule ids are not recognized, assertion values are invalid, or the assertion syntax is not supported. More details of filter processing @@ -1183,24 +1167,24 @@ The matching rule for the greaterOrEqual filter item is defined by the ORDERING and EQUALITY matching rules for the attribute type. 4.5.1.7.4 SearchRequest.filter.lessOrEqual The matching rule for the lessOrEqual filter item is defined by the ORDERING matching rule for the attribute type. 4.5.1.7.5 SearchRequest.filter.present - Lightweight Directory Access Protocol Version 3 - The present match evaluates to TRUE where there is an attribute or subtype of the specified attribute description present in an entry, + Lightweight Directory Access Protocol Version 3 + and FALSE otherwise (including a presence test with an unrecognized attribute description). 4.5.1.7.6 SearchRequest.filter.approxMatch An approxMatch filter item evaluates to TRUE when there is a value of the attribute or subtype for which some locally-defined approximate matching algorithm (e.g. spelling variations, phonetic match, etc.) returns TRUE. If an item matches for equality, it also satisfies an approximate match. If approximate matching is not supported for the @@ -1234,27 +1218,27 @@ The matchingRule used for evaluation determines the syntax for the assertion value. Once the matchingRule and attribute(s) have been determined, the filter item evaluates to TRUE if it matches with at least one attribute in the entry, FALSE if it does not match any attribute in the entry, and Undefined if the matchingRule is not recognized, the matchingRule is unsuitable for use with the specified type, or the assertionValue is invalid. 4.5.1.7 SearchRequest.attributes - Lightweight Directory Access Protocol Version 3 - A selection list of the attributes to be returned from each entry which matches the search filter. LDAPString values of this field are constrained to the following Augmented Backus-Naur Form ([ABNF]): - attributeSelector = attributedescription / selectorpecial + Lightweight Directory Access Protocol Version 3 + + attributeSelector = attributedescription / selectorspecial selectorspecial = noattrs / alluserattrs noattrs = %x31.2E.31 ; "1.1" alluserattrs = %x2A ; asterisk ("*") The production is defined in Section 2.5 of [Models]. @@ -1287,146 +1271,150 @@ listed by name. Operational attributes are described in [Models]. Attributes are returned at most once in an entry. If an attribute description is named more than once in the list, the subsequent names are ignored. If an attribute description in the list is not recognized, it is ignored by the server. 4.5.2. Search Result The results of the Search operation are returned as zero or more - SearchResultEntry and/or zero or more SearchResultReference messages, - followed by a single SearchResultDone message. - - Lightweight Directory Access Protocol Version 3 + SearchResultEntry and/or SearchResultReference messages, followed by + a single SearchResultDone message. SearchResultEntry ::= [APPLICATION 4] SEQUENCE { objectName LDAPDN, attributes PartialAttributeList } + Lightweight Directory Access Protocol Version 3 PartialAttributeList ::= SEQUENCE OF partialAttribute PartialAttribute - -- Note that the PartialAttributeList may hold zero elements. - -- This may happen when none of the attributes of an entry - -- were requested, or could be returned. - -- Note also that the partialAttribute vals set may hold zero - -- elements. This may happen when typesOnly is requested, access - -- controls prevent the return of values, or other reasons. SearchResultReference ::= [APPLICATION 19] SEQUENCE SIZE (1..MAX) OF uri URI SearchResultDone ::= [APPLICATION 5] LDAPResult Each SearchResultEntry represents an entry found during the Search. Each SearchResultReference represents an area not yet explored during the Search. The SearchResultEntry and SearchResultReference PDUs may come in any order. Following all the SearchResultReference and SearchResultEntry responses, the server returns a SearchResultDone response, which contains an indication of success, or detailing any errors that have occurred. Each entry returned in a SearchResultEntry will contain all appropriate attributes as specified in the attributes field of the Search Request, subject to access control and other administrative - policy. + policy. Note that the PartialAttributeList may hold zero elements. + This may happen when none of the attributes of an entry were + requested, or could be returned. Note also that the partialAttribute + vals set may hold zero elements. This may happen when typesOnly is + requested, access controls prevent the return of values, or other + reasons. Some attributes may be constructed by the server and appear in a SearchResultEntry attribute list, although they are not stored attributes of an entry. Clients SHOULD NOT assume that all attributes can be modified, even if permitted by access control. If the server's schema defines short names [Models] for an attribute type then the server SHOULD use one of those names in attribute descriptions for that attribute type (in preference to using the [Models] format of the attribute type's object identifier). The server SHOULD NOT use the short name if that name is known by the server to be ambiguous, or otherwise likely to cause interoperability problems. 4.5.3. Continuation References in the Search Result If the server was able to locate the entry referred to by the - baseObject but was unable to search one or more non-local entries, - the server may return one or more SearchResultReference messages, - each containing a reference to another set of servers for continuing - the operation. A server MUST NOT return any SearchResultReference - messages if it has not located the baseObject and thus has not + baseObject but was unable or unwilling to search one or more non- + local entries, the server may return one or more + SearchResultReference messages, each containing a reference to + another set of servers for continuing the operation. A server MUST + NOT return any SearchResultReference messages if it has not located + the baseObject and thus has not searched any entries; in this case it + would return a SearchResultDone containing either a referral or + noSuchObject result code (depending on the server's knowledge of the + entry named in the baseObject). Lightweight Directory Access Protocol Version 3 - searched any entries; in this case it would return a SearchResultDone - containing either a referral or noSuchObject result code (depending - on the server's knowledge of the entry named in the baseObject). - If a server holds a copy or partial copy of the subordinate naming context (Section 5 of [Models]), it may use the search filter to determine whether or not to return a SearchResultReference response. Otherwise SearchResultReference responses are always returned when in scope. The SearchResultReference is of the same data type as the Referral. - A URI for a server implementing LDAP and accessible via [TCP]/[IP] - (v4 or v6) is written as an LDAP URL according to [LDAPURL]. - - In order to complete the Search, the client issues a new Search - operation for each SearchResultReference that is returned. Note that - the Abandon operation described in Section 4.11 applies only to a - particular operation sent at the LDAP message layer between a client - and server. The client must abandon subsequent Search operations it - wishes to individually. + If the client wishes to progress the Search, it issues a new Search + operation for each SearchResultReference that is returned. If + multiple URIs are present, the client assumes that any supported URI + may be used to progress the operation. Clients that follow search continuation references MUST ensure that they do not loop between servers. They MUST NOT repeatedly contact - the same server for the same request with the same target entry name, - scope and filter. Some clients use a counter that is incremented each - time search result reference handling occurs for an operation, and - these kinds of clients MUST be able to handle at least ten nested - search result references between the root and a leaf entry. + the same server for the same request with the same parameters. Some + clients use a counter that is incremented each time search result + reference handling occurs for an operation, and these kinds of + clients MUST be able to handle at least ten nested referrals while + progressing the operation. + + Note that the Abandon operation described in Section 4.11 applies + only to a particular operation sent at the LDAP message layer between + a client and server. The client must abandon subsequent Search + operations it wishes to individually. + + A URI for a server implementing LDAP and accessible via [TCP]/[IP] + (v4 or v6) is written as an LDAP URL according to [LDAPURL]. SearchResultReference values which are LDAP URLs follow these rules: - - The part of the URL MUST be present, with the new target - object name. The client MUST use this name when following the - reference. UTF-8 encoded characters appearing in the string - representation of a DN or search filter may not be legal for URLs - (e.g. spaces) and MUST be escaped using the % method in [URI]. + - The part of the LDAP URL MUST be present, with the new target + object name. The client uses this name when following the + reference. - Some servers (e.g. participating in distributed indexing) may - provide a different filter in a URL of a SearchResultReference. + provide a different filter in the LDAP URL. - - If the part of the URL is present, the client MUST use + - If the part of the LDAP URL is present, the client uses this filter in its next request to progress this Search, and if it - is not present the client MUST use the same filter as it used for - that Search. + is not present the client uses the same filter as it used for that + Search. - If the originating search scope was singleLevel, the part - of the URL will be "base". + of the LDAP URL will be "base". - It is RECOMMENDED that the part be present to avoid ambiguity. In the absence of a part, the scope of the original Search request is assumed. - Lightweight Directory Access Protocol Version 3 - - Other aspects of the new Search request may be the same as or different from the Search request which generated the SearchResultReference. + Lightweight Directory Access Protocol Version 3 + - The name of an unexplored subtree in a SearchResultReference need not be subordinate to the base object. Other kinds of URIs may be returned. The syntax and semantics of such URIs is left to future specifications. Clients may ignore URIs that they do not support. + UTF-8 encoded characters appearing in the string representation of a + DN, search filter, or other fields of the referral value may not be + legal for URIs (e.g. spaces) and MUST be escaped using the % method + in [URI]. + 4.5.3.1. Examples For example, suppose the contacted server (hosta) holds the entry and the entry . It knows that both LDAP servers (hostb) and (hostc) hold (one is the master and the other server a shadow), and that LDAP-capable server (hostd) holds the subtree . If a wholeSubtree Search of is requested to the contacted server, it may return the following: @@ -1453,25 +1441,24 @@ ldap://hostf/OU=Consultants,OU=People,DC=Example,DC=NET??sub } SearchResultDone (success) Similarly, if a singleLevel Search of is requested to the contacted server, it may return the following: SearchResultEntry for CN=Manager,DC=Example,DC=NET SearchResultReference { ldap://hostb/OU=People,DC=Example,DC=NET??base ldap://hostc/OU=People,DC=Example,DC=NET??base } - SearchResultReference { - ldap://hostd/OU=Roles,DC=Example,DC=NET??base } - Lightweight Directory Access Protocol Version 3 + SearchResultReference { + ldap://hostd/OU=Roles,DC=Example,DC=NET??base } SearchResultDone (success) If the contacted server does not hold the base object for the Search, but has knowledge of its possible location, then it may return a referral to the client. In this case, if the client requests a subtree Search of to hosta, the server returns a SearchResultDone containing a referral. SearchResultDone (referral) { ldap://hostg/DC=Example,DC=ORG??sub } @@ -1507,27 +1494,26 @@ performed MUST conform to the requirements of the directory model and controlling schema [Models]. - operation: Used to specify the type of modification being performed. Each operation type acts on the following modification. The values of this field have the following semantics respectively: add: add values listed to the modification attribute, creating the attribute if necessary; + Lightweight Directory Access Protocol Version 3 delete: delete values listed from the modification attribute. If no values are listed, or if all current values of the attribute are listed, the entire attribute is removed; - Lightweight Directory Access Protocol Version 3 - replace: replace all existing values of the modification attribute with the new values listed, creating the attribute if it did not already exist. A replace with no value will delete the entire attribute if it exists, and is ignored if the attribute does not exist. - modification: A PartialAttribute (which may have an empty SET of vals) used to hold the attribute type or attribute type and values being modified. @@ -1562,26 +1548,25 @@ Section 2.5.1 of [Models] are followed. Note that due to the simplifications made in LDAP, there is not a direct mapping of the changes in an LDAP ModifyRequest onto the changes of a DAP ModifyEntry operation, and different implementations of LDAP-DAP gateways may use different means of representing the change. If successful, the final effect of the operations on the entry MUST be identical. 4.7. Add Operation + Lightweight Directory Access Protocol Version 3 The Add operation allows a client to request the addition of an entry into the Directory. The Add Request is defined as follows: - Lightweight Directory Access Protocol Version 3 - AddRequest ::= [APPLICATION 8] SEQUENCE { entry LDAPDN, attributes AttributeList } AttributeList ::= SEQUENCE OF attribute Attribute Fields of the Add Request are: - entry: the name of the entry to be added. The server SHALL NOT dereference any aliases in locating the entry to be added. @@ -1615,27 +1600,26 @@ A response of success indicates that the new entry has been added to the Directory. 4.8. Delete Operation The Delete operation allows a client to request the removal of an entry from the Directory. The Delete Request is defined as follows: DelRequest ::= [APPLICATION 10] LDAPDN + Lightweight Directory Access Protocol Version 3 The Delete Request consists of the name of the entry to be deleted. The server SHALL NOT dereference aliases while resolving the name of the target entry to be removed. - Lightweight Directory Access Protocol Version 3 - Only leaf entries (those with no subordinate entries) can be deleted with this operation. Upon receipt of a Delete Request, a server will attempt to perform the entry removal requested and return the result in the Delete Response defined as follows: DelResponse ::= [APPLICATION 11] LDAPResult 4.9. Modify DN Operation @@ -1671,27 +1655,25 @@ existing entry. The server SHALL NOT dereference any aliases in locating the objects named in entry or newSuperior. Upon receipt of a ModifyDNRequest, a server will attempt to perform the name change and return the result in the Modify DN Response, defined as follows: ModifyDNResponse ::= [APPLICATION 13] LDAPResult + Lightweight Directory Access Protocol Version 3 For example, if the entry named in the entry field was , the newrdn field was , and the newSuperior field was absent, then this operation would attempt to - - Lightweight Directory Access Protocol Version 3 - rename the entry to be . If there was already an entry with that name, the operation would fail with the entryAlreadyExists result code. Servers MUST ensure that entries conform to user and system schema rules or other data model constraints. For attribute types which specify no equality matching, the rules in Section 2.5.1 of [Models] are followed (this pertains to newrdn and deleteoldrdn). The object named in newSuperior MUST exist. For example, if the @@ -1727,27 +1709,26 @@ - entry: the name of the entry to be compared. The server SHALL NOT dereference any aliases in locating the entry to be compared. - ava: holds the attribute value assertion to be compared. Upon receipt of a Compare Request, a server will attempt to perform the requested comparison and return the result in the Compare Response, defined as follows: + Lightweight Directory Access Protocol Version 3 + CompareResponse ::= [APPLICATION 15] LDAPResult The resultCode is set to compareTrue, compareFalse, or an appropriate error. compareTrue indicates that the assertion value in the ava - - Lightweight Directory Access Protocol Version 3 - field matches a value of the attribute or subtype according to the attribute's EQUALITY matching rule. compareFalse indicates that the assertion value in the ava field and the values of the attribute or subtype did not match. Other result codes indicate either that the result of the comparison was Undefined (Section 4.5.1), or that some error occurred. Note that some directory systems may establish access controls which permit the values of certain attributes (such as userPassword) to be compared but not interrogated by other means. @@ -1770,38 +1751,38 @@ by the MessageID. Since the client cannot tell the difference between a successfully abandoned operation and an uncompleted operation, the application of the Abandon operation is limited to uses where the client does not require an indication of its outcome. Abandon, Bind, Unbind, and StartTLS operations cannot be abandoned. In the event that a server receives an Abandon Request on a Search operation in the midst of transmitting responses to the Search, that server MUST cease transmitting entry responses to the abandoned - request immediately, and MUST NOT send the SearchResponseDone. Of + request immediately, and MUST NOT send the SearchResultDone. Of course, the server MUST ensure that only properly encoded LDAPMessage PDUs are transmitted. The ability to abandon other (particularly update) operations is at the discretion of the server. Clients should not send Abandon requests for the same operation multiple times, and MUST also be prepared to receive results from operations it has abandoned (since these may have been in transit when the Abandon was requested, or are not able to be abandoned). + Lightweight Directory Access Protocol Version 3 + Servers MUST discard Abandon requests for message IDs they do not recognize, for operations which cannot be abandoned, and for operations which have already been abandoned. - Lightweight Directory Access Protocol Version 3 - 4.12. Extended Operation The Extended operation allows additional operations to be defined for services not already available in the protocol. For example, to Add operations to install transport layer security (see Section 4.14). The Extended operation allows clients to make requests and receive responses with predefined syntaxes and semantics. These may be defined in RFCs or be private to particular implementations. @@ -1836,29 +1817,29 @@ protocolError. The requestValue and responseValue fields contain any information associated with the operation. The format of these fields is defined by the specification of the Extended operation. Implementations MUST be prepared to handle arbitrary contents of these fields, including zero bytes. Values that are defined in terms of ASN.1 and BER encoded according to Section 5.1, also follow the extensibility rules in Section 4. + Lightweight Directory Access Protocol Version 3 + Servers list the requestName of Extended Requests they recognize in the 'supportedExtension' attribute in the root DSE (Section 5.1 of [Models]). Extended operations may be specified in other documents. The specification of an Extended operation consists of: - Lightweight Directory Access Protocol Version 3 - - the OBJECT IDENTIFIER assigned to the requestName, - the OBJECT IDENTIFIER (if any) assigned to the responseName (note that the same OBJECT IDENTIFIER my be used for both the requestName and responseName), - the format of the contents of the requestValue and responseValue (if any), and - the semantics of the operation. @@ -1891,29 +1872,28 @@ unless the client issues a request that specifically solicits their return. This document defines two forms of solicitation: Extended operation and request control. IntermediateResponse messages are specified in documents describing the manner in which they are solicited (i.e. in the Extended operation or request control specification that uses them). These specifications include: - the OBJECT IDENTIFIER (if any) assigned to the responseName, - the format of the contents of the responseValue (if any), and + Lightweight Directory Access Protocol Version 3 - the semantics associated with the IntermediateResponse message. Extensions that allow the return of multiple types of IntermediateResponse messages SHALL identify those types using unique responseName values (note that one of these may specify no value). - Lightweight Directory Access Protocol Version 3 - Sections 4.13.1 and 4.13.2 describe additional requirements on the inclusion of responseName and responseValue in IntermediateResponse messages. 4.13.1. Usage with LDAP ExtendedRequest and ExtendedResponse A single-request/multiple-response operation may be defined using a single ExtendedRequest message to solicit zero or more IntermediateResponse messages of one or more kinds followed by an ExtendedResponse message. @@ -1941,30 +1921,30 @@ The Start Transport Layer Security (StartTLS) operation's purpose is to initiate installation of a TLS layer. The StartTLS operation is defined using the Extended operation mechanism described in Section 4.12. 4.14.1. StartTLS Request A client requests TLS establishment by transmitting a StartTLS request PDU to the server. The StartTLS request is defined in terms + Lightweight Directory Access Protocol Version 3 + of an ExtendedRequest. The requestName is "1.3.6.1.4.1.1466.20037", and the requestValue field is always absent. The client MUST NOT send any PDUs at this LDAP message layer following this request until it receives a StartTLS Extended response and, in the case of a successful response, completes TLS negotiations. - Lightweight Directory Access Protocol Version 3 - Detected sequencing problems (particularly those detailed in Section 3.1.1 of [AuthMeth]) result in the resultCode being set to operationsError. If the server does not support TLS (whether by design or by current configuration), it returns with the resultCode set to protocolError as described in Section 4.12. 4.14.2. StartTLS Response @@ -1978,64 +1958,48 @@ details. If the server is otherwise unwilling or unable to perform this operation, the server is to return an appropriate result code indicating the nature of the problem. For example, if the TLS subsystem is not presently available, the server may indicate so by returning with the resultCode set to unavailable. 4.14.3. Removal of the TLS Layer - Two forms of TLS layer removal -- graceful and abrupt -- are - provided. These do not involve LDAP PDUs, but are preformed at the - underlying layers. - - If the transport connection is closed, uncompleted operations are - handled as specified in Section 5.1. - -4.14.3.1. Graceful Removal - Either the client or server MAY remove the TLS layer and leave the LDAP message layer intact by sending and receiving a TLS closure alert. The initiating protocol peer sends the TLS closure alert. If it wishes to leave the LDAP message layer intact, it then MUST cease to send further PDUs and MUST ignore any received LDAP PDUs until it receives a TLS closure alert from the other peer. Once the initiating protocol peer receives a TLS closure alert from the other peer it MAY send and receive LDAP PDUs. - Lightweight Directory Access Protocol Version 3 - When a protocol peer receives the initial TLS closure alert, it may choose to allow the LDAP message layer to remain intact. In this + Lightweight Directory Access Protocol Version 3 + case, it MUST immediately transmit a TLS closure alert. Following this, it MAY send and receive LDAP PDUs. - Protocol peers MAY close the transport connection after sending or + Protocol peers MAY terminate the LDAP session after sending or receiving a TLS closure alert. After the TLS layer has been removed, the server MUST NOT send responses to any request message received before the TLS closure alert. Thus, clients wishing to receive responses to messages sent while the TLS layer is intact MUST wait for those message responses before sending the TLS closure alert. -4.14.3.2. Abrupt Removal - - Either the client or server MAY abruptly remove the TLS layer by - closing the transport connection. In this circumstance, a server MAY - send the client a Notice of Disconnection before closing the - transport connection. - 5. Protocol Encoding, Connection, and Transfer This protocol is designed to run over connection-oriented, reliable transports, where the data stream is divided into octets (8-bit units), with each octet and each bit being significant. One underlying service, LDAP over TCP, is defined in Section 5.2. This service is generally applicable to applications providing or consuming X.500-based directory services on the Internet. This specification was generally written with the TCP mapping in mind. @@ -2052,33 +2016,32 @@ | LDAP message layer | +----------------------+ > LDAP PDUs +----------------------+ < data | SASL layer | +----------------------+ > SASL-protected data +----------------------+ < data | TLS layer | Application +----------------------+ > TLS-protected data ------------+----------------------+ < data Transport | transport connection | - - Lightweight Directory Access Protocol Version 3 - +----------------------+ 5.1. Protocol Encoding The protocol elements of LDAP SHALL be encoded for exchange using the Basic Encoding Rules [BER] of [ASN.1] with the following restrictions: - Only the definite form of length encoding is used. + Lightweight Directory Access Protocol Version 3 + - OCTET STRING values are encoded in the primitive form only. - If the value of a BOOLEAN type is true, the encoding of the value octet is set to hex "FF". - If a value of a type is its default value, it is absent. Only some BOOLEAN and INTEGER types have default values in this protocol definition. These restrictions are meant to ease the overhead of encoding and @@ -2091,36 +2054,53 @@ 5.2. Transmission Control Protocol (TCP) The encoded LDAPMessage PDUs are mapped directly onto the [TCP] bytestream using the BER-based encoding described in Section 5.1. It is recommended that server implementations running over the TCP provide a protocol listener on the Internet Assigned Numbers Authority (IANA)-assigned LDAP port, 389 [PortReg]. Servers may instead provide a listener on a different port number. Clients MUST support contacting servers on any valid TCP port. +5.3. Termination of the LDAP session + + Termination of the LDAP session is typically initiated by the client + sending an UnbindRequst (Section 4.3), or by the server sending a + Notice of Disconnection (Section 4.4.1). In these cases each protocol + peer gracefully terminates the LDAP session by ceasing exchanges at + the LDAP message layer, tearing down any SASL layer, tearing down any + TLS layer, and closing the transport connection. + + A protocol peer may determine that the continuation of any + communication would be pernicious, and in this case may abruptly + terminate the session by ceasing communication and closing the + transport connection. + + In either case, when the LDAP session is terminated, uncompleted + operations are handled as specified in Section 3.1. + 6. Security Considerations This version of the protocol provides facilities for simple authentication using a cleartext password, as well as any [SASL] mechanism. Installing SASL and/or TLS layers can provide integrity and other data security services. + Lightweight Directory Access Protocol Version 3 + It is also permitted that the server can return its credentials to the client, if it chooses to do so. Use of cleartext password is strongly discouraged where the underlying transport service cannot guarantee confidentiality and may result in disclosure of the password to unauthorized parties. - Lightweight Directory Access Protocol Version 3 - Servers are encouraged to prevent directory modifications by clients that have authenticated anonymously [AuthMeth]. Security considerations for authentication methods, SASL mechanisms, and TLS are described in [AuthMeth]. It should be noted that SASL authentication exchanges do not provide data confidentiality nor integrity protection for the version or name fields of the BindRequest nor the resultCode, diagnosticMessage, or referral fields of the BindResponse nor of any information contained @@ -2154,29 +2134,34 @@ reject referrals from the StartTLS operation. The matchedDN and diagnosticMessage fields, as well as some resultCode values (e.g., attributeOrValueExists and entryAlreadyExists), could disclose the presence or absence of specific data in the directory which is subject to access and other administrative controls. Server implementations should restrict access to protected information equally under both normal and error conditions. + Lightweight Directory Access Protocol Version 3 + Protocol peers MUST be prepared to handle invalid and arbitrary length protocol encodings. Invalid protocol encodings include: BER encoding exceptions, format string and UTF-8 encoding exceptions, overflow exceptions, integer value exceptions, and binary mode on/off flag exceptions. The LDAPv3 PROTOS [PROTOS-LDAP] test suite provides excellent examples of these exceptions and test cases used to discover flaws. - Lightweight Directory Access Protocol Version 3 + In the event that a protocol peer senses an attack which in its + nature could cause damage due to further communication at any layer + in the LDAP session, the protocol peer should abruptly terminate the + LDAP session as described in Section 5.3. 7. Acknowledgements This document is based on RFC 2251 by Mark Wahl, Tim Howes, and Steve Kille. RFC 2251 was a product of the IETF ASID Working Group. It is also based on RFC 2830 by Jeff Hodges, RL "Bob" Morgan, and Mark Wahl. RFC 2830 was a product of the IETF LDAPEXT Working Group. It is also based on RFC 3771 by Roger Harrison, and Kurt Zeilenga. @@ -2200,37 +2185,36 @@ xx.txt, (a work in progress). [BER] ITU-T Rec. X.690 (07/2002) | ISO/IEC 8825-1:2002, "Information technology - ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER)", 2002. [IP] Postel, J., "Internet Protocol", STD5 and RFC 791, September 1981 + Lightweight Directory Access Protocol Version 3 [ISO10646] Universal Multiple-Octet Coded Character Set (UCS) - Architecture and Basic Multilingual Plane, ISO/IEC 10646-1 : 1993. [Keyword] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997. [LDAPDN] Zeilenga, K., "LDAP: String Representation of Distinguished Names", draft-ietf-ldapbis-dn-xx.txt, (a work in progress). [LDAPIANA] Zeilenga, K., "IANA Considerations for LDAP", draft-ietf- ldapbis-bcp64-xx.txt, (a work in progress). - Lightweight Directory Access Protocol Version 3 - [LDAPURL] Smith, M., "LDAP: Uniform Resource Locator", draft-ietf- ldapbis-url-xx.txt, (a work in progress). [Models] Zeilenga, K., "LDAP: Directory Information Models", draft- ietf-ldapbis-models-xx.txt (a work in progress). [Roadmap] Zeilenga, K., "LDAP: Technical Specification Road Map", draft-ietf-ldapbis-roadmap-xx.txt (a work in progress). [SASL] Melnikov, A., "Simple Authentication and Security Layer", @@ -2255,37 +2239,37 @@ draft-ietf-tls-rfc2246-bis-xx.txt, a work in progress. [Unicode] The Unicode Consortium, "The Unicode Standard, Version 3.2.0" is defined by "The Unicode Standard, Version 3.0" (Reading, MA, Addison-Wesley, 2000. ISBN 0-201-61633-5), as amended by the "Unicode Standard Annex #27: Unicode 3.1" (http://www.unicode.org/reports/tr27/) and by the "Unicode Standard Annex #28: Unicode 3.2" (http://www.unicode.org/reports/tr28/). + Lightweight Directory Access Protocol Version 3 + [URI] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifiers (URI): Generic Syntax", RFC 2396, August 1998. [UTF-8] Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD63 and RFC3629, November 2003. [X.500] ITU-T Rec. X.500, "The Directory: Overview of Concepts, Models and Service", 1993. [X.501] ITU-T Rec. X.501, "The Directory: Models", 1993. [X.511] ITU-T Rec. X.511, "The Directory: Abstract Service Definition", 1993. - Lightweight Directory Access Protocol Version 3 - 9. Informative References [Glossary] The Unicode Consortium, "Unicode Glossary", . [CharModel] Whistler, K. and M. Davis, "Unicode Technical Report #17, Character Encoding Model", UTR17, , August 2000. @@ -2308,25 +2292,27 @@ definitive technical specification for the StartTLS (1.3.6.1.4.1.1466.20037) Extended operation. It is requested that the IANA update the occurrence of "RFC XXXX" in Appendix B with this RFC number at publication. 11. Editor's Address Jim Sermersheim Novell, Inc. + + Lightweight Directory Access Protocol Version 3 + 1800 South Novell Place Provo, Utah 84606, USA jimse@novell.com +1 801 861-3088 - Lightweight Directory Access Protocol Version 3 Appendix A - LDAP Result Codes This normative appendix details additional considerations regarding LDAP result codes and provides a brief, general description of each LDAP result code enumerated in Section 4.1.9. Additional result codes MAY be defined for use with extensions [LDAPIANA]. Client implementations SHALL treat any result code which @@ -2402,23 +2388,23 @@ Undefined. compareTrue (6) Indicates that the Compare operation has successfully completed and the assertion has evaluated to TRUE. authMethodNotSupported (7) Indicates that the authentication method or mechanism is not supported. - strongAuthRequired (8) - Indicates the server requires the client to authenticate - using a strong(er) mechanism. + strongerAuthRequired (8) + Indicates the server requires strong(er) authentication in + order to complete the operation. When used with the Notice of Disconnection operation, this code indicates that the server has detected that an established security association between the client and server has unexpectedly failed or been compromised. referral (10) Indicates that a referral needs to be chased to complete the operation (see Section 4.1.10). @@ -2642,21 +2626,21 @@ LDAPResult ::= SEQUENCE { resultCode ENUMERATED { success (0), operationsError (1), protocolError (2), timeLimitExceeded (3), sizeLimitExceeded (4), compareFalse (5), compareTrue (6), authMethodNotSupported (7), - strongAuthRequired (8), + strongerAuthRequired (8), -- 9 reserved -- referral (10), adminLimitExceeded (11), unavailableCriticalExtension (12), confidentialityRequired (13), saslBindInProgress (14), noSuchAttribute (16), undefinedAttributeType (17), inappropriateMatching (18), constraintViolation (19), @@ -2743,21 +2725,21 @@ derefFindingBaseObj (2), derefAlways (3) }, sizeLimit INTEGER (0 .. maxInt), timeLimit INTEGER (0 .. maxInt), typesOnly BOOLEAN, filter Filter, attributes AttributeSelection } AttributeSelection ::= SEQUENCE OF selector LDAPString -- The LDAPString is constrained to - -- in Section 4.5.1 + -- in Section 4.5.1.7 Filter ::= CHOICE { and [0] SET SIZE (1..MAX) OF filter Filter, or [1] SET SIZE (1..MAX) OF filter Filter, not [2] Filter, equalityMatch [3] AttributeValueAssertion, substrings [4] SubstringFilter, greaterOrEqual [5] AttributeValueAssertion, lessOrEqual [6] AttributeValueAssertion, present [7] AttributeDescription, @@ -2888,21 +2867,21 @@ - Removed the requirement that servers which implement version 3 or later MUST provide the 'supportedLDAPVersion' attribute. This statement provided no interoperability advantages. C.1.4 Section 4.1.1 (Message Envelope) - There was a mandatory requirement for the server to return a Notice of Disconnection and drop the transport connection when a PDU is malformed in a certain way. This has been updated such that the server SHOULD return the Notice of Disconnection, and MUST - drop the transport connection. + terminate the LDAP Session. C.1.5 Section 4.1.1.1 (Message ID) - Required that the messageID of requests MUST be non-zero as the zero is reserved for Notice of Disconnection. Lightweight Directory Access Protocol Version 3 - Specified when it is and isn't appropriate to return an already used message id. RFC 2251 accidentally imposed synchronous server @@ -2924,44 +2903,47 @@ - Combined the definitions of PartialAttribute and Attribute here, and defined Attribute in terms of PartialAttribute. C.1.9 Section 4.1.10 (Result Message) - Renamed "errorMessage" to "diagnosticMessage" as it is allowed to be sent for non-error results. - Moved some language into Appendix A, and refer the reader there. - Allowed matchedDN to be present for other result codes than those listed in RFC 2251. + - renamed the code "strongAuthRequired" to "strongerAuthRequired" to + clarify that this code may often be returned to indicate that a + stronger authentication is needed to perform a given operation. C.1.10 Section 4.1.11 (Referral) - Defined referrals in terms of URIs rather than URLs. - Removed the requirement that all referral URIs MUST be equally capable of progressing the operation. The statement was ambiguous and provided no instructions on how to carry it out. - Added the requirement that clients MUST NOT loop between servers. - Clarified the instructions for using LDAPURLs in referrals, and in doing so added a recommendation that the scope part be present. - Removed imperatives which required clients to use URLs in specific ways to progress an operation. These did nothing for interoperability. C.1.11 Section 4.1.12 (Controls) - Specified how control values defined in terms of ASN.1 are to be encoded. - - Noted that the criticality field is only applied to request - messages (except UnbindRequest), and must be ignored when present - on response messages and UnbindRequest. Lightweight Directory Access Protocol Version 3 + - Noted that the criticality field is only applied to request + messages (except UnbindRequest), and must be ignored when present + on response messages and UnbindRequest. - Added language regarding combinations of controls and the ordering of controls on a message. - Specified that when the semantics of the combination of controls is undefined or unknown, it results in a protocolError. - Changed "The server MUST be prepared" to "Implementations MUST be prepared" in the eighth paragraph to reflect that both client and server implementations must be able to handle this (as both parse controls). C.1.12 Section 4.2 (Bind Operation) @@ -2995,29 +2977,30 @@ - Mandated that clients not send non-Bind operations while a Bind is in progress, and suggested that servers not process them if they are received. This is needed to ensure proper sequencing of the Bind in relationship to other operations. C.1.14 Section 4.2.3 (Bind Response) - Moved most error-related text to Appendix A, and added text regarding certain errors used in conjunction with the Bind operation. - - Prohibited the server from specifying serverSaslCreds when not - appropriate. Lightweight Directory Access Protocol Version 3 + - Prohibited the server from specifying serverSaslCreds when not + appropriate. + C.1.15 Section 4.3 (Unbind Operation) - - Specified that both peers are to cease transmission and close the - transport connection for the Unbind operation. + - Specified that both peers are to cease transmission and terminate + the LDAP session for the Unbind operation. C.1.16 Section 4.4 (Unsolicited Notification) - Added instructions for future specifications of Unsolicited Notifications. C.1.17 Section 4.5.1 (Search Request) - SearchRequest attributes is now defined as an AttributeSelection type rather than AttributeDescriptionList, and an ABNF is @@ -3044,40 +3027,39 @@ - Recommended that servers not use attribute short names when it knows they are ambiguous or may cause interoperability problems. - Removed all mention of ExtendedResponse due to lack of implementation. C.1.19 Section 4.5.3 (Continuation References in the Search Result) - Made changes similar to those made to Section 4.1.11. C.1.20 Section 4.5.3.1 (Example) + Lightweight Directory Access Protocol Version 3 - Fixed examples to adhere to changes made to Section 4.5.3. C.1.21 Section 4.6 (Modify Operation) - Lightweight Directory Access Protocol Version 3 - - Replaced AttributeTypeAndValues with Attribute as they are equivalent. - - Spcified the types of modification changes which might temporarily - violate schema. Some readers were under the impression that any - temporary schema violation was allowed. + - Specified the types of modification changes which might + temporarily violate schema. Some readers were under the impression + that any temporary schema violation was allowed. C.1.22 Section 4.7 (Add Operation) - Aligned Add operation with X.511 in that the attributes of the RDN are used in conjunction with the listed attributes to create the entry. Previously, Add required that the distinguished values be present in the listed attributes. - - Removed requirement that the objectclass attribute MUST be + - Removed requirement that the objectClass attribute MUST be specified as some DSE types do not require this attribute. Instead, generic wording was added, requiring the added entry to adhere to the data model. - Removed recommendation regarding placement of objects. This is covered in the data model document. C.1.23 Section 4.9 (Modify DN Operation) - Required servers to not dereference aliases for Modify DN. This was added for consistency with other operations and to help ensure @@ -3095,26 +3077,24 @@ added for consistency with other operations and to help ensure data consistency. C.1.25 Section 4.11 (Abandon Operation) - Explained that since Abandon returns no response, clients should not use it if they need to know the outcome. - Specified that Abandon and Unbind cannot be abandoned. C.1.26 Section 4.12 (Extended Operation) + Lightweight Directory Access Protocol Version 3 - Specified how values of Extended operations defined in terms of ASN.1 are to be encoded. - - Lightweight Directory Access Protocol Version 3 - - Added instructions on what Extended operation specifications consist of. - Added a recommendation that servers advertise supported Extended operations. C.1.27 Section 5.2 (Transfer Protocols) - Moved referral-specific instructions into referral-related sections. @@ -3146,27 +3126,29 @@ to other sections. C.2.1 Section 2.3 (Response other than "success") - Removed wording indicating that referrals can be returned from StartTLS. - Removed requirement that only a narrow set of result codes can be returned. Some result codes are required in certain scenarios, but any other may be returned if appropriate. -C.2.1 Section 4 (Closing a TLS Connection) - Lightweight Directory Access Protocol Version 3 +C.2.1 Section 4 (Closing a TLS Connection) + - Reworded most of this section and added the requirement that after the TLS connection has been closed, the server MUST NOT send responses to any request message received before the TLS closure. + - Removed instructions on abrupt closure as this is covered in other + areas of the document (specifically, Section 5.3) C.3 Changes made to RFC 3771: - Rewrote to fit into this document. In general, semantics were preserved. Supporting and background language seen as redundant due to its presence in this document was omitted. - Specified that Intermediate responses to a request may be of different types, and one of the response types may be specified to have no response value.