Network Working Group M. Wahl INTERNET-DRAFT ISODE Consortium Obsoletes: RFC 1777, RFC 1798 T. Howes University of Michigan S. Kille ISODE Consortium Expires in six months from 23 February 1996 Intended Category: Standards Track Lightweight Directory Access Protocol (v3) 1. Status of this Memo This document is an Internet-Draft. 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." To learn the current status of any Internet-Draft, please check the "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow Directories on ds.internic.net (US East Coast), nic.nordu.net (Europe), ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific Rim). 2. Abstract The protocol described in this document is designed to provide access to X.500 Directories while not incurring the resource requirements of the Directory Access Protocol (DAP). This protocol is specifically targeted at management applications and browser applications that provide read/write interactive access to the X.500 Directory, and is intended to be a complement to the DAP itself. Key aspects of this version of LDAP are: - All protocol elements of LDAP (RFC 1777) and CLDAP (RFC 1798) are supported. - Protocol elements are carried directly over TCP or other transport, bypassing much of the session/presentation overhead. Connectionless transport (UDP) is also supported for efficient lookup operations. - If desired, many protocol data elements can be encoded as ordinary strings (e.g., Distinguished Names). - Important parameters of X.500(1993) DAP can be used. INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 - Referrals to other servers may be returned. - The protocol may be extended to support bilaterally-defined operations. - Several of the service controls may be requested by the client. 3. Models Interest in X.500 [1] technology in the Internet has lead to efforts to reduce the high "cost of entry" associated with use of the technology. This document continues the efforts to define Directory protocol alternatives: it builds heavily on the LDAP [2] protocol specification, and allows support for additional X.500(1993) features. 3.1. Protocol Model The general model adopted by this protocol is one of clients performing protocol operations against servers. In this model, this is accomplished by a client transmitting a protocol request describing the operation to be performed to a server, which is then responsible for performing the necessary operations on the Directory. Upon completion of the necessary operations, the server returns a response containing any results or errors to the requesting client. In keeping with the goal of easing the costs associated with use of the Directory, it is an objective of this protocol to minimize the complexity of clients so as to facilitate widespread deployment of applications capable of utilizing the Directory. Note that, although servers are required to return responses whenever such responses are defined in the protocol, there is no requirement for synchronous behavior on the part of either client or server implementations: requests and responses for multiple operations may be exchanged by client and servers in any order, as long as clients eventually receive a response for every request that requires one. In LDAP versions 1 and 2, no provision was made for protocol servers returning referrals to clients. However, for improved performance and distribution this version of the protocol permits servers to return to clients referrals to other servers if requested. Clients may also request that no referrals be returned, in which case the server must ensure that the operation is performed against the Directory, or else return an error. Note that this protocol can be mapped to a strict subset of the directory abstract service, so it can be cleanly provided by the DAP. However there is not a one-to-one mapping between LDAP protocol operations and DAP operations: some server implementations may need to make multiple DAP requests to perform extended operations. 3.2. Data Model This section provides a brief introduction to the X.500 data model, as used by LDAP. Schema rules and other features are not described here. INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 The LDAP protocol assumes there is one or more servers which jointly provide access to a Directory Information Tree. The tree is made up of entries. Entries have names: one or more values from the entry itself form its relative distinguished name, which must be unique among all its siblings. The concatenation of the relative distinguished names of entries, starting from the immediate subordinate of the unnamed root of the tree and continuing to a specific entry form's that entry's Distinguished Name, which is unique in the tree. An example of a Distinguished Name is Entries consist of a set of attributes. An attribute is a type with one or more values associated with that type. The attribute type is an OID (object identifier) which governs the maximum number of values permissible for that type in an entry, and the syntax to which the values must conform. An example of an attribute type is "rfc822Mailbox": the values of this attribute must be IA5 strings. All the attributes of an entry are mastered together in a single server. Shadow or cached copies of entries may be held in other servers, but these cannot be updated directly by users. 3.3. Relationship to X.500 This document defines LDAP in terms of X.500 as an X.500 access mechanism. An LDAP server should act in accordance with the X.500(1993) series of ITU Recommendations when providing the service. However, it is not required that an LDAP server make use of any X.500 protocols in providing this service: e.g. LDAP can be mapped onto any other Directory system so long as the X.500 data and service model is supported in the LDAP interface. 3.4. Additional server data requirements An LDAP server must provide a number of attributes in the root DSE, that which is named with the zero-length LDAPDN. These attributes should be retrievable if a client performs a base object search of the root. They should not be included if the client performs a subtree search starting from the root. The server need not allow the client to modify these attributes. The attributes are as follows: - administratorAddress This attribute's value is a string containing the RFC 822 address of the LDAP server's human administrator. This information may be of use when tracking down problems in a distributed directory. INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 - currentTime This attribute's value is a string containing a UTCTime character value. This attribute need only be present if the server supports strong or protected simple authentication. Otherwise if the server does not know the current time this attribute should not be present. The client may wish to use this field to detect whether a strong or protected bind would fail because the client and server clocks are not sufficiently synchronized. Clients should not use this time field for setting their own system clock. - binaryName This attribute's value is the binary ASN.1 encoding of the server's Distinguished Name. If the server does not have a Distinguished Name it will not be able to accept strong authentication, and this attribute should be absent. - path This attribute contains a binary encoding of the AF.CertificationPath data type, with the certificate path for the server. If the server does not have a certificate path this attribute should be absent. - context The values of this attribute are the string representations of Distinguished Names. Each value corresponds to a naming context which this server masters or shadows. If the server does not master any information (e.g. it is an LDAP gateway to a public X.500 Directory) this attribute should be absent. If the server believes it contains the entire Directory, the attribute should have a single value, and that value should be the empty string (indicating the null DN of the root). - altLdapServer The values of this attribute are URLs of other LDAP servers which may be contacted when this server becomes unavailable. If the server does not know of any other LDAP servers which could be used this attribute should be absent. Clients should cache this information in case their preferred LDAP server later becomes unavailable. - altX500Server The values of this attribute are encoded with the AccessPoint93 syntax. They are the access points of X.500 DSAs which could be contacted when this server becomes unavailable. If this server does not know of any X.500 DSAs this attribute should be absent. Clients which support DAP should cache this information in case their preferred LDAP server later becomes unavailable. - supportedExtension The values of this attribute are the string representations of OBJECT IDENTIFIERs, in the dotted decimal form. Each value is the name of an extended request which this server supports (see section 4.11). If the server does not support any extended operations this attribute should be absent. The ASN.1 type DistinguishedName is defined in [6], and the type CertificationPath is defined in [12]. They are included in Appendix B for reference. INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 4. Elements of Protocol The LDAP protocol is described using Abstract Syntax Notation 1 [3]. It is typically transferred using a subset of the Basic Encoding Rules. In order to support future extensions to this protocol, clients and servers should ignore elements of SEQUENCEs whose tags they do not recognize. 4.1. Common Elements This section describes the LDAPMessage envelope PDU format, as well as data type definitions which are used in the protocol operations. 4.1.1. Message Envelope For the purposes of protocol exchanges, all protocol operations are encapsulated in a common envelope, the LDAPMessage, which is defined as follows: LDAPMessage ::= SEQUENCE { messageID MessageID, cldapUserName LDAPDN OPTIONAL, protocolOp CHOICE { bindRequest BindRequest, bindRespBasic BindResponseBasic, bindRespExtd BindResponseExtended, unbindRequest UnbindRequest, searchRequest SearchRequest, searchResEntry SearchResultEntry, searchResDone SearchResultDone, searchResRef SearchResultReference, searchResFull SearchResultFull, modifyRequest ModifyRequest, modifyResponse ModifyResponse, addRequest AddRequest, addResponse AddResponse, delRequest DelRequest, delResponse DelResponse, modDNRequest ModifyDNRequest, modDNResponse ModifyDNResponse, compareRequest CompareRequest, compareResponse CompareResponse, abandonRequest AbandonRequest, extendedReq ExtendedRequest, extendedResp ExtendedResponse } } MessageID ::= INTEGER (0 .. maxInt ) maxInt INTEGER ::= 2147483647 -- (2^^31 - 1) -- -- later may be extended to 9223372036854775807 (2^^63 - 1) -- 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 message ID and cldapUserName. INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 The message ID is required to have a value different from the values of any other requests outstanding in the LDAP session of which this message is a part. Typically a client may increment a counter for each request. The message ID value must be echoed in all LDAPMessage envelopes encapsulating responses corresponding to the request contained in the LDAPMessage in which the message ID value was originally used. The cldapUserName identifies the requesting user for this message. It is only present if this LDAPMessage is carried in a connectionless transport protocol, such as UDP. This is described in section 5.1.3. When the LDAP session is carried in a connection-oriented transport protocol this field must be absent. 4.1.2. String The LDAPString is a notational convenience to indicate that, although strings of LDAPString type encode as OCTET STRING types, the legal character set in such strings is limited to the IA5 character set. LDAPString ::= OCTET STRING 4.1.3. Distinguished Name and Relative Distinguished Name An LDAPDN and a RelativeLDAPDN are respectively defined to be the representation of a Distinguished Name and a Relative Distinguished Name after encoding according to the specification in [4], such that ::= ::= where and are as defined in [4]. LDAPDN ::= LDAPString RelativeLDAPDN ::= LDAPString 4.1.4. Attribute Type An AttributeType takes on as its value the textual string associated with that AttributeType in its specification. If this string is not known, the AttributeType should take the ASCII representation of its OBJECT IDENTIFIER, as decimal digits with components separated by periods, e.g. "2.5.4.10". The attribute type strings which must be supported are described in section [5]. AttributeType ::= LDAPString This data type describes a list of 0 or more attribute types. Clients and servers should be prepared to accept a list of many hundreds of attribute types. AttributeTypeList ::= SEQUENCE SIZE (0..maxInt) OF AttributeType INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 4.1.5. Attribute Value A field of type AttributeValue takes on as its value an octet string encoding of a Directory AttributeValue type. The definition of these string encodings for different Directory AttributeValue types may be found in companions to this document that define the encodings of various attribute syntaxes such as [5]. AttributeValue ::= OCTET STRING Note that there is no defined limit on the size of this encoding; thus PDUs including multi-megabyte photograph attributes may be returned. If the client has limited memory or storage capabilities it may wish to set the attrSizeLimit field when invoking a search operation. 4.1.6. Attribute Value Assertion The AttributeValueAssertion type definition is similar to the one in the X.500 Directory standards. It contains an attribute type and a equality matching assertion suitable for that type. AttributeValueAssertion ::= SEQUENCE { attributeType AttributeType, assertionValue AssertionValue } AssertionValue ::= OCTET STRING For all the standard attributes, the assertion value syntax is the same as the value syntax. 4.1.7. Attribute An attribute consists of a type and one or more values of that type. Attribute ::= SEQUENCE { type AttributeType, vals SET SIZE (1..maxInt) OF AttributeValue } Clients and servers should be prepared to accept attributes with many hundreds of values. 4.1.8. Matching Rule Identifier An X.501(1993) Matching Rule is identified in the LDAP protocol by the ASCII representation of its OBJECT IDENTIFIER, as decimal digits with components separated by periods, e.g. "1.3.6.1.4.1.453.33.33". MatchingRuleId ::= LDAPString 4.1.9. Result Message The LDAPResult is the construct used in this protocol to return success or failure indications from servers to clients. In response to various requests, servers will return responses containing fields of type LDAPResult to indicate the final status of a protocol operation request. INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 LDAPResult ::= SEQUENCE { resultCode ENUMERATED { success (0), operationsError (1), protocolError (2), timeLimitExceeded (3), sizeLimitExceeded (4), compareFalse (5), compareTrue (6), authMethodNotSupported (7), strongAuthRequired (8), -- 9 reserved -- referral (10), -- new adminLimitExceeded (11), -- new unavailableCriticalExtension (12), -- new -- 14-15 unused -- noSuchAttribute (16), undefinedAttributeType (17), inappropriateMatching (18), constraintViolation (19), attributeOrValueExists (20), invalidAttributeSyntax (21), -- 22-31 unused -- noSuchObject (32), aliasProblem (33), invalidDNSyntax (34), isLeaf (35), aliasDereferencingProblem (36), -- 37-47 unused -- inappropriateAuthentication (48), invalidCredentials (49), insufficientAccessRights (50), busy (51), unavailable (52), unwillingToPerform (53), loopDetect (54), -- 55-63 unused -- namingViolation (64), objectClassViolation (65), notAllowedOnNonLeaf (66), notAllowedOnRDN (67), entryAlreadyExists (68), objectClassModsProhibited (69), resultsTooLarge (70), -- cl only affectsMultipleDSAs (71), -- new -- 72-79 unused -- other (80) }, matchedDN LDAPDN, errorMessage LDAPString (SIZE (0..maxInt)), referral [3] Referral OPTIONAL, matchedSubtype [4] AttributeType OPTIONAL } INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 The errorMessage field of this construct may, at the servers option, be used to return an ASCII string containing a textual, human-readable error diagnostic. As this error diagnostic is not standardized, implementations should not rely on the values returned. If the server chooses not to return a textual diagnostic, the errorMessage field of the LDAPResult type should contain a zero length string. For resultCodes of noSuchObject, aliasProblem, invalidDNSyntax, isLeaf, and aliasDereferencingProblem, the matchedDN field is set to the name of the lowest entry (object or alias) in the DIT that was matched and is a truncated form of the name provided or, if an alias has been dereferenced, of the resulting name in a Search or Compare result. The matchedDN field should be set to a NULL DN (a zero length string) in all other cases. When the resultCode is compareTrue or compareFalse the matchedSubtype field will contain the type name of the attribute whose value matched the ava in the Compare operation. 4.1.10. Referral The referral field is present in an LDAPResult if the LDAPResult.resultCode field value is referral. It contains a reference to another server (or set of servers) which may be accessed via LDAP or other protocols. Referral ::= SEQUENCE { servers [0] SET SIZE (1..maxInt) OF LDAPURL } The servers field contains a list of URLs of servers, and each must be capable of processing the operation and presenting a consistent view to clients. URLs for servers implementing the LDAP protocol are written according to [9]. LDAPURL ::= LDAPString The ASN.1 type Exclusions is defined in [10], and is included in Appendix B for reference. The server should place its own URL in the referringServer field, as this information may be useful for tracing referral loops and inconsistencies. 4.2. Bind Operation The function of the Bind Operation is to initiate a protocol session between a client and a server, and to allow the authentication of the client to the server. The Bind Request is defined as follows: INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 BindRequest ::= [APPLICATION 0] SEQUENCE { version INTEGER (1 .. 127), name LDAPDN, authentication AuthenticationChoice, serviceControls [7] Controls OPTIONAL } AuthenticationChoice ::= CHOICE { simple [1] OCTET STRING, krbv42LDAP [2] OCTET STRING, krbv42DSA [3] OCTET STRING, protected [4] ProtectedPassword, strong [5] StrongCredentials, nonstandard [6] NonstandardCredentials } ProtectedPassword ::= SEQUENCE { time1 [0] UTCTime OPTIONAL, time2 [1] UTCTime OPTIONAL, random1 [2] BIT STRING OPTIONAL, random2 [3] BIT STRING OPTIONAL, protected [4] OCTET STRING } StrongCredentials ::= SEQUENCE { certification-path [0] AF.CertificationPath OPTIONAL, bind-token [1] DAS.Token } NonstandardCredentials ::= SEQUENCE { authMechanism [0] LDAPString, authToken [1] OCTET STRING } Controls ::= SEQUENCE SIZE (1..maxInt) OF SEQUENCE { criticality [0] BOOLEAN DEFAULT FALSE, control ServiceControl } ServiceControl ::= CHOICE { referringServer [0] LDAPURL, chainingProhibited [1] BOOLEAN, scopeOfReferral [2] ENUMERATED { any(-1), dmd(0), country(1) }, referToLDAPServers [3] BOOLEAN, referToDAPServers [4] BOOLEAN, preferredSyntax [5] SyntaxEncoding, extendedControl [6] ExtendedControl } SyntaxEncoding ::= SEQUENCE { attributeType [0] AttributeType, encodingPreference [1] SyntaxName } SyntaxName ::= LDAPString ExtendedControl ::= SEQUENCE { controlName [0] LDAPString, controlValue [1] OCTET STRING } INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 Parameters of the Bind Request are: - version: A version number indicating the version of the protocol to be used in this protocol session. This document describes version 3 of the LDAP protocol. Note that there is no version negotiation, and the client should just set this parameter to the version it desires. The client may request version 2, in which case the server should implement only the protocol as described in [2], by NOT returning: - BindResponseExtended in response to this request, - result codes referral, adminLimitExceeded, unavailableCriticalExtension, resultsTooLarge or affectsMultipleDSAs, - referral or matchedSubtype in LDAPResult, - fromEntry in SearchResultEntry, - SearchResultReference in response to searches. - name: The name of the Directory object that the client wishes to bind as. This field may take on a null value (a zero length string) for the purposes of anonymous binds. - authentication: information used to authenticate the name, if any, provided in the Bind Request. - serviceControls: additional requests the client may make about the protocol. Upon receipt of a Bind Request, a protocol server will authenticate the requesting client if necessary, and attempt to set up a protocol session with that client. The server will then return a Bind Response to the client indicating the status of the session setup request. Unlike LDAP v2, the client need not send a Bind Request in the first PDU of the connection. The client may request any operations and the server should treat these as unauthenticated. If the server requires that the client bind first, the server should reject any request other that binding or unbinding with the "operationsError" result. If the client did not bind before sending a request and receives an operationsError, it should close the connection, reopen it and begin again by first sending a PDU with a Bind Request. This will aid in interoperating with LDAPv2 servers. Clients should not send more than one Bind Request on a connection. 4.2.1 Authentication The "simple" authentication option provides minimal authentication facilities, with the contents of the authentication field consisting only of a cleartext password. This option should also be used when unauthenticated or anonymous binds are to be performed, with the field containing a zero length string in such cases. INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 Kerberos version 4 [14] authentication to the LDAP server and the DSA is accomplished by using the krbv42LDAP and krbv42DSA authentication options, respectively. Note that though they are referred to as separate entities here, there is no requirement these two entities be distinct (i.e., a DSA could speak LDAP directly). Two separate authentication options are provided to support all implementations. Each octet string should contain the kerberos ticket (e.g., as returned by krb_mk_req()) for the appropriate service. The suggested service name for authentication to the LDAP server is "ldapserver". The suggested service name for authentication to the DSA is "x500dsa". In both cases, the suggested instance name for the service is the name of the host on which the service is running. Of course, the actual service names and instances will depend on what is entered in the local kerberos principle database. The ProtectedPassword authentication option allows a hash of the password, combined optionally with the current time and a random number, to be sent to the DSA. The protected field contains the hash value. Strong authentication to the Directory can be accomplished using the strong credentials option. The ASN.1 type "CertificationPath" is defined in [12], and the ASN.1 type "Token" is defined in [13]. They are included in Appendix B for Reference. Nonstandard authentication to the Directory can be performed using the nonstandard credentials option. The authMechanism must be the dotted-decimal printable representation of an OBJECT IDENTIFIER of that authentication mechanism: for interoperability the full decimal format must be used. The authToken is arbitrary information of a form defined by that authentication mechanism, encoded in an OCTET STRING. 4.2.1.1. Strong Credentials Signature Algorithm It is recommended for interoperability that if strong authentication is to be performed, then if the server's or client's certificates contain RSA public keys the PKCS md5WithRSAEncryption (1.2.840.113549.1.1.4) algorithm should be used. 4.2.2. Service Controls Service Controls are requests made by the client which affect its interaction with the server. Controls are not saved after a session unbinds or disconnects abruptly, and do not affect other sessions to this or other servers. If the server is not capable of setting one or more requested controls, it should set as many as possible. If any of the controls which the server could not set are marked as critical, it should return the unavailableCriticalExtension error. The referringServer control is non-critical. This field contains the URL of another server which referred an operation to this server. This control should only be present if the connection is being made only to process a referral. If the connection will be held open to handle referrals from other servers this control should be omitted. If the chainingProhibited field is set to TRUE, the server set the chainingProhibited service control on any DAP requests it makes. If the referToLDAPServers or returnToDAPServers fields are set to TRUE, the server should return referrals to clients. Otherwise if neither of these are set to TRUE the server should itself follow referrals. INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 If the referToLDAPServers field is set to TRUE, the server is permitted by the client to return referrals to other LDAP servers. If the referToDAPServers field is set to TRUE, the server is permitted by the client to return referrals to other X.500 servers which accept incoming DAP associations. The preferredSyntax fields control how the server should in Search Responses return values of attributes, and how it should interpret values presented in Compare, Add and Modify arguments. The attribute field is the attribute whose syntax preference is being noted, if the field is a zero length string the preference applies to all attributes. The following encodingPref values have been defined: - The zero-length empty string corresponds to the default syntax for the server. It may be binary, readable or something else for each attribute. - The string "binary" requests that the binary BER encoding be used for the selected (or all) attributes. Note that Attribute Types, as well as distinguished names transferred as protocol elements (not as attribute values) are still carried in string representations. - The string "readable" requests that printable encodings be used for the selected attributes, and that IA5 character sets be used where possible. If the attribute field is of zero length this requests the server to encode unrecognized attributes using the "Readable" default encoding. Subsequent documents may define additional encoding preference values to support internationalization. The extendedControl is used to exchange bilaterally-defined information from a client to a server. The controlName must be the dotted-decimal printable representation of an OBJECT IDENTIFIER of that control: for interoperability the full decimal format must be used. The controlValue is arbitrary information of a form defined by that control, encoded in an OCTET STRING. 4.2.3. Bind Response The Bind Response will be one of the following, either BindResponseBasic or BindResponseExtended. BindResponseBasic ::= [APPLICATION 1] LDAPResult A BindResponseBasic consists simply of an indication from the server of the status of the client's request for the initiation of a protocol session. If the bind was successful, the resultCode will be success, otherwise it will be one of: INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 operationsError protocolError authMethodNotSupported strongAuthRequired referral inappropriateAuthentication invalidCredentials unavailable If the client receives a BindResponseBasic response where the resultCode was not success, it should close the connection as the server will be unwilling to accept further operations. A BindResponseExtended will only be returned if the bind was successful and additional information is to be returned to the client. BindResponseExtended ::= [APPLICATION 17] SEQUENCE { serverURL [0] LDAPURL, serverCreds AuthenticationChoice } The serverURL contains the URL of this LDAP server. The serverCreds allows the client to authenticate the server to which it is communicating. 4.3. Unbind Operation The function of the Unbind Operation is to terminate a protocol session. The Unbind Operation is defined as follows: UnbindRequest ::= [APPLICATION 2] NULL The Unbind Operation has no response defined. Upon transmission of an UnbindRequest, a protocol client may assume that the protocol session is terminated. Upon receipt of an UnbindRequest, a protocol server may assume that the requesting client has terminated the session and that all outstanding requests may be discarded. 4.4. Search Operation The Search Operation allows a client to request that a search be performed on its behalf by a server. The Search Request is defined as follows: SearchRequest ::= [APPLICATION 3] SEQUENCE { baseObject LDAPDN, scope ENUMERATED { baseObject (0), singleLevel (1), wholeSubtree (2) }, derefAliases ENUMERATED { neverDerefAliases (0), derefInSearching (1), derefFindingBaseObj (2), derefAlways (3) }, sizeLimit INTEGER (0 .. maxInt), timeLimit INTEGER (0 .. maxInt), INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 typesOnly BOOLEAN, filter Filter, attributes AttributeTypeList, matchedOnly [0] BOOLEAN DEFAULT FALSE, sortKeys [1] SortKeyList OPTIONAL, reverseSort [2] BOOLEAN DEFAULT FALSE, modifyRightsReq [3] BOOLEAN DEFAULT FALSE, extraAttributes [4] BOOLEAN DEFAULT FALSE, attrSizeLimit [5] INTEGER OPTIONAL, subentries [6] BOOLEAN DEFAULT FALSE, dontUseCopy [7] BOOLEAN DEFAULT FALSE } SortKeyList ::= SEQUENCE SIZE (1..maxInt) OF SEQUENCE { attributeType AttributeType, orderingRule [0] MatchingRuleId OPTIONAL, startFrom [1] AssertionValue OPTIONAL, endWith [2] AssertionValue OPTIONAL } Filter ::= CHOICE { and [0] SET SIZE (1..maxInt) OF Filter, or [1] SET SIZE (1..maxInt) OF Filter, not [2] Filter, equalityMatch [3] AttributeValueAssertion, substrings [4] SubstringFilter, greaterOrEqual [5] AttributeValueAssertion, lessOrEqual [6] AttributeValueAssertion, present [7] AttributeType, approxMatch [8] AttributeValueAssertion, extensibleMatch [9] MatchingRuleAssertion } SubstringFilter ::= SEQUENCE { type AttributeType, substrings SEQUENCE SIZE (1..maxInt) OF CHOICE { initial [0] LDAPString, any [1] LDAPString, final [2] LDAPString } } MatchingRuleAssertion ::= SEQUENCE { matchingRules [1] SET SIZE (0..maxInt) OF MatchingRuleId, type [2] AttributeType, matchValue [3] AssertionValue, dnAttributes [4] BOOLEAN } Parameters of the Search Request are: - baseObject: An LDAPDN that is the base object entry relative to which the search is to be performed. - scope: An indicator of the scope of the search to be performed. The semantics of the possible values of this field are identical to the semantics of the scope field in the Directory Search Operation. - derefAliases: An indicator as to how alias objects should be handled in searching. The semantics of the possible values of this field are: INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 neverDerefAliases: do not dereference aliases in searching or in locating the base object of the search; derefInSearching: dereference aliases in subordinates of the base object in searching, but not in locating the base object of the search; derefFindingBaseObject: 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. - sizelimit: A sizelimit that restricts the maximum number of entries to be returned as a result of the search. A value of 0 in this field indicates that no sizelimit restrictions are in effect for the search. - timelimit: A timelimit that restricts the maximum time (in seconds) allowed for a search. A value of 0 in this field indicates that no timelimit restrictions are in effect for the search. - typesOnly: An indicator as to whether search results should contain both attribute types and values, or just attribute types. Setting this field to TRUE causes only attribute types (no values) to be returned. Setting this field to FALSE causes both attribute types and values to be returned. - filter: A filter that defines the conditions that must be fulfilled in order for the search to match a given entry. The and, or and not choices may be used to form boolean combinations of filters. - attributes: A list of the attributes from each entry found as a result of the search to be returned. An empty list signifies that all attributes from each entry found in the search are to be returned. - matchedOnly: If this field is set to TRUE, then in search results if there are multivalued attributes where some but not all of the values contributed to the search filter returning TRUE via filters other than equality or present, then the values which did not contribute are not returned in the entry attribute list. - sortKeys: If this field is present, then it specifies one or more attribute types and matching rules, and the returned entries should be sorted in order based on these types. The startFrom and endWith assertion values specify a range of entries which are to be returned. If an entry matches a specified sortKey but with a value before the startFrom assertion or after the endWith assertion, that entry is not returned as a result. INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 If the server does not recognize any of the attribute types, or the ordering rule associated with an attribute type is not applicable, or none of the attributes in the search responses are of these types, then the sortKeys field is ignored and result entries are returned in random order. Support for this field is optional, and clients should expect that not all servers will implement result sorting. - reverseSort: If this field is set to TRUE and the sortKeys field is also present, then the entries will be presented in reverse sorted order. - modifyRightsReq: If this field is set to TRUE and the scope field is set to baseObject, then the client requests that the modification rights for the entry be included in the search result. Support for this field is optional, and clients should expect that not all servers will implement returning modify rights. - extraAttributes: If this field is present and set to TRUE then all operational attributes are requested to be returned as well. Note that specific operational attributes may instead be listed in the attributes field. Servers are permitted to ignore extraAttributes if returning this information is prohibited by security policy. Clients should note that many operational attributes are not modifiable. - attrSizeLimit: If this field is present, then if the size in bytes of an attribute and all its values which would be returned in a result entry exceeds this size in bytes, then the attribute is not included in the result and the incompleteEntry field is set to TRUE. - subentries: if present and set to TRUE, the server should ignore ordinary entries and only perform the search against subentries. If the server not support subentries and this field is TRUE it should not do any searching, and either return an error (protocolError) or an empty result. - dontUseCopy: if present and set to TRUE, only the server which holds the master copy of the entry is permitted to perform the filtering and attribute selection. The results of the search attempted by the server upon receipt of a Search Request are returned in Search Responses, which are LDAP messages containing either SearchResultEntry, SearchResultReference, SearchResultDone or SearchResultFull data types. SearchResultEntry ::= [APPLICATION 4] SEQUENCE { objectName LDAPDN, attributes PartialAttributeList, modifyRights [2] ModifyRights OPTIONAL, incompleteEntry [3] BOOLEAN DEFAULT FALSE, fromEntry [4] BOOLEAN DEFAULT FALSE } INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 PartialAttributeList ::= SEQUENCE SIZE (0..maxInt) OF SEQUENCE { type AttributeType, vals SET SIZE (0..maxInt) OF AttributeValue } SearchResultReference ::= [APPLICATION 18] Referral SearchResultDone ::= [APPLICATION 5] LDAPResult SearchResultFull ::= SEQUENCE SIZE (1..maxInt) OF CHOICE { entry SearchResultEntry, reference SearchResultReference, resultCode SearchResultDone } ModifyRights ::= SEQUENCE { entryRemove BOOLEAN, entryModifyDN BOOLEAN, attrRights SET SIZE (0..maxInt) OF SEQUENCE { type AttributeType, grantAdd BOOLEAN, grantRemove BOOLEAN } } Upon receipt of a Search Request, a server will perform the necessary search of the DIT. If the LDAP session is operating over a connection-oriented transport such as TCP, the server will return to the client a sequence of responses in separate LDAP messages. There may be zero or more responses containing SearchResultEntry, one for each entry found during the search. There may also be zero or more responses containing SearchResultReference, one for each area not explored by this server during the search. There must always be a final response containing the SearchResultDone, which contains an indication of success, or detailing any errors that have occurred. If the LDAP session is operating over a connectionless transport such as UDP, the server will return to the client only one response, a LDAPMessage containing a SearchResultFull data type. All if any but the last element of the SEQUENCE OF must be of the SearchResultEntry type, and the last must be of the SearchResultDone type. Each entry returned in a SearchResultEntry will contain all attributes, complete with associated values if necessary, as specified in the attributes field of the Search Request. In a SearchResultEntry, as an encoding optimisation, the value of the objectName LDAP DN may use a trailing '*' character to refer to the baseObject of the corresponding searchRequest. For example, if the baseObject is specified as "o=UofM, c=US", then the following objectName LDAPDNs in a response would have the indicated meanings objectName returned actual LDAPDN denoted ____________________________________________________ "*" "o=UofM, c=US" "cn=Babs Jensen, *" "cn=Babs Jensen, o=UofM, c=US" INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 If (and only if) the modifyRightsReq field was present in the Search Request may the server also include the ModifyRights field in the entry. This field details the operations which are expected to succeed if requested by that user later in this session. The server need not guarantee that these permissions will be granted, however it should avoid suggesting permissions that are not currently granted. If no information is available the server should not include the modifyRights field in the response. The incompleteEntry flag is set if one or more attributes are not present in the PartialAttributeList, because their size would have exceeded the attribute size limit. It is never set if typesOnly was set to TRUE. The server may set the fromEntry field in a SearchResult entry to TRUE if it is known that the search is not based upon a shadow or cached copy of the entry, but that the source of entry data has been directly contacted. If the server was able to locate the entry referred to by the baseObject but was unable to search all the entries in the scope at and under the baseObject, the server may return one or more SearchResultReference, each containing a reference to another LDAP or to an X.500 server for continuing the operation. The server should return at most one SearchResultReference for a subtree. A server must not return a SearchResultReference if it has located the baseObject and thus has not searched any entries; in this case it should return a SearchResultDone containing a referral resultCode and the continuationReference. Note that an X.500 "list" operation can be emulated by a one-level LDAP search operation with a filter checking for the existence of the objectClass attribute, and that an X.500 "read" operation can be emulated by a base object LDAP search operation with the same filter. 4.5. Modify Operation The Modify Operation allows a client to request that a modification of the DIB be performed on its behalf by a server. The Modify Request is defined as follows: ModifyRequest ::= [APPLICATION 6] SEQUENCE { object LDAPDN, modification SEQUENCE SIZE (1..maxInt) OF SEQUENCE { operation ENUMERATED { add (0), delete (1), replace (2) }, modification Attribute } } Parameters of the Modify Request are: - object: The object to be modified. The value of this field should name the object to be modified. The server will not perform any alias dereferencing in determining the object to be modified. INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 - A list of modifications to be performed on the entry to be modified. The entire list of entry modifications should be performed in the order they are listed, as a single atomic operation. While individual modifications may violate the Directory schema, the resulting entry after the entire list of modifications is performed must conform to the requirements of the Directory schema. The values that may be taken on by the 'operation' field in each modification construct have the following semantics respectively: add: add values listed to the given attribute, creating the attribute if necessary; delete: delete values listed from the given attribute, removing the entire attribute if no values are listed, or if all current values of the attribute are listed for deletion; replace: replace existing values of the given attribute with the new values listed, creating the attribute if necessary. The result of the modify attempted by the server upon receipt of a Modify Request is returned in a Modify Response, defined as follows: ModifyResponse ::= [APPLICATION 7] LDAPResult Upon receipt of a Modify Request, a server will perform the necessary modifications to the DIB. The server will return to the client a single Modify Response indicating either the successful completion of the DIB modification, or the reason that the modification failed. Note that due to the requirement for atomicity in applying the list of modifications in the Modify Request, the client may expect that no modifications of the DIB have been performed if the Modify Response received indicates any sort of error, and that all requested modifications have been performed if the Modify Response indicates successful completion of the Modify Operation. 4.6. Add Operation The Add Operation allows a client to request the addition of an entry into the Directory. The Add Request is defined as follows: AddRequest ::= [APPLICATION 8] SEQUENCE { entry LDAPDN, attributes AttributeList } AttributeList ::= SEQUENCE SIZE (1..maxInt) OF SEQUENCE { type AttributeType, vals SET SIZE (1..maxInt) OF AttributeValue } INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 Parameters of the Add Request are: - entry: the Distinguished Name of the entry to be added. Note that all components of the name except for the last RDN component must exist for the add to succeed. Note also that the server will not dereference any aliases in locating the entry to be added, and that there are never any entries subordinate to an alias entry. - attributes: the list of attributes that make up the content of the entry being added. The result of the add attempted by the server upon receipt of a Add Request is returned in the Add Response, defined as follows: AddResponse ::= [APPLICATION 9] LDAPResult Upon receipt of an Add Request, a server will attempt to perform the add requested. The result of the add attempt will be returned to the client in the Add Response. 4.7. 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 The Delete Request consists of the Distinguished Name of the entry to be deleted. Note that the server will not dereference aliases while resolving the name of the target entry to be removed. The result of the delete attempted by the server upon receipt of a Delete Request is returned in the Delete Response, defined as follows: DelResponse ::= [APPLICATION 11] LDAPResult Upon receipt of a Delete Request, a server will attempt to perform the entry removal requested. The result of the delete attempt will be returned to the client in the Delete Response. Note that only leaf objects may be deleted with this operation. 4.8. Modify DN Operation The Modify DN Operation allows a client to change the last component of the name of an entry in the Directory, or to move a subtree of entries to a new location in the Directory. The Modify DN Request is defined as follows: INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 ModifyDNRequest ::= [APPLICATION 12] SEQUENCE { entry LDAPDN, newrdn RelativeLDAPDN, deleteoldrdn BOOLEAN, newSuperior [0] LDAPDN OPTIONAL } Parameters of the Modify DN Request are: - entry: the name of the entry to be changed. - newrdn: the RDN that will form the last component of the new name. - deleteoldrdn: a boolean parameter that controls whether the old RDN attribute values should be retained as attributes of the entry or deleted from the entry. - newSuperior: if present, this is the name of another entry which should be the superior of the subtree in the entry field. The result of the name change attempted by the server upon receipt of a Modify DN Request is returned in the Modify DN Response, defined as follows: ModifyDNResponse ::= [APPLICATION 13] LDAPResult Upon receipt of a Modify RDN Request, a server will attempt to perform the name change. The result of the name change attempt will be returned to the client in the Modify DN Response. The attributes that make up the old RDN are deleted from the entry, or kept, depending on the setting of the deleteoldrdn parameter. 4.9. Compare Operation The Compare Operation allows a client to compare an assertion provided with an entry in the Directory. The Compare Request is defined as follows: CompareRequest ::= [APPLICATION 14] SEQUENCE { entry LDAPDN, ava AttributeValueAssertion, timeLimit [0] INTEGER (0 .. maxInt) OPTIONAL, dontUseCopy [1] BOOLEAN DEFAULT FALSE } Parameters of the Compare Request are: - entry: the name of the entry to be compared with. - ava: the assertion with which an attribute in the entry is to be compared. INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 - timeLimit: the maximum time in seconds the server should spend in handling this operation. - dontUseCopy: if present and set to TRUE, only the server which holds the master copy of the entry is permitted to return the compareTrue or compareFalse results. The result of the compare attempted by the server upon receipt of a Compare Request is returned in the Compare Response, defined as follows: CompareResponse ::= [APPLICATION 15] LDAPResult Upon receipt of a Compare Request, a server will attempt to perform the requested comparison. The result of the comparison will be returned to the client in the Compare Response. Note that errors and the result of comparison are all returned in the same construct. This operation is defined for backwards compatability with earlier versions of LDAP. Any new clients written should not use the comparison operation, but instead should use the search operation, with scope set to baseObject and filter containing one element, an equality match. Note that different results will be returned than from the comparison operation: in search if the filter match is successful, the entry will be returned, and if the attribute value is not present, no entries will be returned. 4.10. Abandon Operation The function of the Abandon Operation is to allow a client to request that the server abandon an outstanding operation. The Abandon Request is defined as follows: AbandonRequest ::= [APPLICATION 16] MessageID The MessageID must be that of a Search or Compare operation which was requested earlier during this association. Other types of operations cannot be abandoned. There is no response defined in the Abandon Operation. Upon transmission of an Abandon Operation, a client may expect that the operation identified by the Message ID in the Abandon Request has been abandoned. In the event that a server receives an Abandon Request on a Search Operation in the midst of transmitting responses to that search, that server should cease transmitting entry responses to the abandoned search immediately. INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 4.11 Extended Operation The following operation allows clients to make requests of forms not defined in this document. The requestName is a dotted-decimal representation of the OBJECT IDENTIFIER corresponding to the request. The requestValue is information in a form defined by that request, encapsulated inside an OCTET STRING. ExtendedRequest ::= [APPLICATION 23] SEQUENCE { requestName [0] LDAPString, requestValue [1] OCTET STRING } The server will respond to this with an LDAPMessage containing the ExtendedResponse. ExtendedResponse ::= [APPLICATION 24] SEQUENCE { response [0] OCTET STRING OPTIONAL, standardResponse [1] LDAPResult } If the server does not recognize the operation name, it should return only the standardResponse, containing the protocolError result code. 5. Protocol Element Encodings and Transfer The protocol elements of LDAP are encoded for exchange using the Basic Encoding Rules (BER) [11] of ASN.1 [3]. However, due to the high overhead involved in using certain elements of the BER, the following additional restrictions are placed on BER-encodings of LDAP protocol elements: (1) Only the definite form of length encoding will be used. (2) Bitstrings and octet strings and all character string types will be encoded in the primitive form only. (3) UTC Times should be encoded with the "Z" suffix, not as a local time. (4) If the value of a BOOLEAN type is true, the encoding should have its contents octets set to hex "FF". (5) The components of a SET type, currently only DO.AccessPoint, should be encoded in ascending order of tag value. (6) Unused bits in the final octet of the encoding of a BIT STRING value, if there are any, should always be set to zero. (7) If a value of a type is its default value, it should be absent. Only BOOLEAN and ENUMERATED types have default values. These restrictions do not apply to ASN.1 types encapsulated inside of OCTET STRINGs. INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 5.1. Mapping Onto Transport Services This protocol is designed to run over connection-oriented, reliable transports, with all 8 bits in an octet being significant in the data stream. For compatibility with the existing LDAP v2 and CLDAP protocols, three underlying services are defined here. However an LDAP server need not implement all three. Separate documents may define other mappings, such as to a MIME Content-type for use in messaging and WWW. 5.1.1. Transmission Control Protocol (TCP) The LDAPMessage PDUs are mapped directly onto the TCP bytestream. Server implementations running over the TCP should provide a protocol listener on port 389. 5.1.2. Connection Oriented Transport Service (COTS) The connection is established. No special use of T-Connect is made. Each LDAPMessage PDU is mapped directly onto T-Data. 5.1.3. User Datagram Protocol (UDP) The LDAPMessage PDUs are mapped directly onto UDP datagrams. Only one request may be sent in a single datagram. Only one response may be sent in a single datagram. Server implementations running over the UDP should provide a protocol listener on port 389. The only operations which the client may request are searchRequest and abandonRequest. The server may only respond with the searchResultFull. 6. Implementation Guidelines 6.1. Server Implementations The server should be capable of recognizing all the attribute type names and implement the syntaxes specified in [5]. Servers may also recognize additional attribute type names. In order to prevent confusion, the server should respond with the OID form for the "uniqueIdentifier" standard and pilot attribute. 6.2. Client Implementations As there is a conflict of names, the client must not request the "uniqueIdentifier" attribute. Instead it should use the OID form. For simple lookup applications using the connectionless transport protocol UDP, use of a retry algorithm with multiple servers similar to that commonly used in DNS stub resolver implementations is recommended. The location of a CLDAP server or servers may be better specified using IP addresses (simple or broadcast) rather than names that must first be looked up in another directory such as DNS. INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 Servers will not dereference aliases encountered when performing an Add, Delete or Modify operation. If an alias was encountered an error will be returned. The client must retry the operation with an updated target entry name. Note that multiple aliases may be encounted while resolving the entry's true name. 7. Security Considerations When used with a connection-oriented transport, this version of the protocol provides facilities for the LDAP v2 authentication mechanisms: simple authentication using a cleartext password and kerberos version 4 authentication. It also provides for two other authentication mechanisms as described in X.511: transfer of a hash of the client's password, and strong authentication based on the private key of the client. When used with the connectionless transport, no security services are available. There has been some discussion about the desirability of authentication with connectionless LDAP requests. This might take the form of a clear text password (which would go against the current IAB drive to remove such things from protocols) or some arbitrary credentials. It is felt that, in general, authentication would incur sufficient overhead to negate the advantages of the connectionless basis of CLDAP. If an application requires authenticated access to the Directory then CLDAP is not an appropriate protocol. 8. Acknowledgements This document is based heavily on RFC 1777, by Wengyik Yeong, Tim Howes, and Steve Kille. It also includes material from RFC 1798, by Alan Young. Design ideas included in this document are based on those discussed in ASID and other IETF Working Groups. 9. Bibliography [1] The Directory: Overview of Concepts, Models and Service. ITU-T Recommendation X.500, 1993. [2] W. Yeong, T. Howes, S. Kille, "Lightweight Directory Access Protocol", RFC 1777, March 1995. [3] Specification of Abstract Syntax Notation One (ASN.1). CCITT Recommendation X.208, 1988. [4] S. Kille, "A String Representation of Distinguished Names", RFC 1779, March 1995. [5] M. Wahl, A. Coulbeck, T. Howes, S. Kille, W. Yeong, C. Robbins, "Lightweight X.500 Directory Access Protocol Standard and Pilot Attribute Definitions", , February 1996. [6] The Directory: Models. ITU-T Recommendation X.501, 1993. [7] The Directory: Selected Attribute Types. ITU-T Recommendation X.520, 1993. INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 [9] T. Howes, M. Smith, An LDAP URL Format, December 1995, [10] The Directory: Procedures for Distributed Operation. ITU-T Recommendation X.518, 1993. [11] Specification of Basic Encoding Rules for Abstract Syntax Notation One (ASN.1). CCITT Recommendation X.209, 1988. [12] The Directory: Authentication Framework. ITU-T Recommendation X.509, 1993. [13] The Directory: Abstract Service Definition. ITU-T Recommendation X.511, 1993. [14] Kerberos Authentication and Authorization System. S.P. Miller, B.C. Neuman, J.I. Schiller, J.H. Saltzer; MIT Project Athena Documentation Section E.2.1, December 1987. 10. Authors' Address Mark Wahl ISODE Consortium Inc. 3925 West Braker Lane, Suite 333 Austin, TX 78759 USA Phone: +1 512-305-0280 EMail: M.Wahl@isode.com Tim Howes University of Michigan ITD Research Systems 535 W William St. Ann Arbor, MI 48103-4943 USA Phone: +1 313 747-4454 EMail: tim@umich.edu Steve Kille ISODE Consortium The Dome, The Square Richmond TW9 1DT UK Phone: +44-181-332-9091 EMail: S.Kille@isode.com INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 Appendix A - Complete ASN.1 Definition In the IMPORTS statement the "AF" module refers to X.509(1993), and the "DAS" module to X.511(1993). Lightweight-Directory-Access-Protocol-V3 DEFINITIONS IMPLICIT TAGS ::= BEGIN IMPORTS CertificationPath FROM AF Token FROM DAS; LDAPMessage ::= SEQUENCE { messageID MessageID, cldapUserName LDAPDN OPTIONAL, protocolOp CHOICE { bindRequest BindRequest, bindRespBasic BindResponseBasic, bindRespExtd BindResponseExtended, unbindRequest UnbindRequest, searchRequest SearchRequest, searchResEntry SearchResultEntry, searchResDone SearchResultDone, searchResRef SearchResultReference, searchResFull SearchResultFull, modifyRequest ModifyRequest, modifyResponse ModifyResponse, addRequest AddRequest, addResponse AddResponse, delRequest DelRequest, delResponse DelResponse, modDNRequest ModifyDNRequest, modDNResponse ModifyDNResponse, compareRequest CompareRequest, compareResponse CompareResponse, abandonRequest AbandonRequest, extendedReq ExtendedRequest, extendedResp ExtendedResponse } } INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 MessageID ::= INTEGER (0 .. maxInt ) maxInt INTEGER ::= 2147483647 -- (2^^31 - 1) -- -- later may be extended to 9223372036854775807 (2^^63 - 1) -- LDAPString ::= OCTET STRING LDAPDN ::= LDAPString RelativeLDAPDN ::= LDAPString AttributeType ::= LDAPString AttributeTypeList ::= SEQUENCE SIZE (0..maxInt) OF AttributeType AttributeValue ::= OCTET STRING AttributeValueAssertion ::= SEQUENCE { attributeType AttributeType, assertionValue AssertionValue } AssertionValue ::= OCTET STRING Attribute ::= SEQUENCE { type AttributeType, vals SET SIZE (1..maxInt) OF AttributeValue } MatchingRuleId ::= LDAPString LDAPResult ::= SEQUENCE { resultCode ENUMERATED { success (0), operationsError (1), protocolError (2), timeLimitExceeded (3), sizeLimitExceeded (4), compareFalse (5), compareTrue (6), authMethodNotSupported (7), strongAuthRequired (8), -- 9 reserved -- referral (10), -- new adminLimitExceeded (11), -- new unavailableCriticalExtension (12), -- new -- 14-15 unused -- noSuchAttribute (16), undefinedAttributeType (17), inappropriateMatching (18), constraintViolation (19), attributeOrValueExists (20), invalidAttributeSyntax (21), -- 22-31 unused -- noSuchObject (32), aliasProblem (33), invalidDNSyntax (34), isLeaf (35), aliasDereferencingProblem (36), INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 -- 37-47 unused -- inappropriateAuthentication (48), invalidCredentials (49), insufficientAccessRights (50), busy (51), unavailable (52), unwillingToPerform (53), loopDetect (54), -- 55-63 unused -- namingViolation (64), objectClassViolation (65), notAllowedOnNonLeaf (66), notAllowedOnRDN (67), entryAlreadyExists (68), objectClassModsProhibited (69), resultsTooLarge (70), -- cl only affectsMultipleDSAs (71), -- new -- 72-79 unused -- other (80) }, matchedDN LDAPDN, errorMessage LDAPString (SIZE (0..maxInt)), referral [3] Referral OPTIONAL, matchedSubtype [4] AttributeType OPTIONAL } Referral ::= SEQUENCE { servers [0] SET SIZE (1..maxInt) OF LDAPURL } LDAPURL ::= OCTET STRING BindRequest ::= [APPLICATION 0] SEQUENCE { version INTEGER (1 .. 127), name LDAPDN, authentication AuthenticationChoice, serviceControls [7] Controls OPTIONAL } AuthenticationChoice ::= CHOICE { simple [1] OCTET STRING, krbv42LDAP [2] OCTET STRING, krbv42DSA [3] OCTET STRING, protected [4] ProtectedPassword, strong [5] StrongCredentials, nonstandard [6] NonstandardCredentials } INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 ProtectedPassword ::= SEQUENCE { time1 [0] UTCTime OPTIONAL, time2 [1] UTCTime OPTIONAL, random1 [2] BIT STRING OPTIONAL, random2 [3] BIT STRING OPTIONAL, protected [4] OCTET STRING } StrongCredentials ::= SEQUENCE { certification-path [0] AF.CertificationPath OPTIONAL, bind-token [1] DAS.Token } NonstandardCredentials ::= SEQUENCE { authMechanism [0] LDAPString, authToken [1] OCTET STRING } Controls ::= SEQUENCE SIZE (1..maxInt) OF SEQUENCE { criticality [0] BOOLEAN DEFAULT FALSE, control ServiceControl } ServiceControl ::= CHOICE { referringServer [0] LDAPURL, chainingProhibited [1] BOOLEAN, scopeOfReferral [2] ENUMERATED { any(-1), dmd(0), country(1) }, referToLDAPServers [3] BOOLEAN, referToDAPServers [4] BOOLEAN, preferredSyntax [5] SyntaxEncoding, extendedControl [6] ExtendedControl } SyntaxEncoding ::= SEQUENCE { attributeType [0] AttributeType, encodingPreference [1] SyntaxName } SyntaxName ::= LDAPString ExtendedControl ::= SEQUENCE { controlName [0] LDAPString, controlValue [1] OCTET STRING } BindResponseBasic ::= [APPLICATION 1] LDAPResult BindResponseExtended ::= [APPLICATION 17] SEQUENCE { serverURL [0] LDAPURL, serverCreds AuthenticationChoice } UnbindRequest ::= [APPLICATION 2] NULL SearchRequest ::= [APPLICATION 3] SEQUENCE { baseObject LDAPDN, scope ENUMERATED { baseObject (0), singleLevel (1), wholeSubtree (2) }, INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 derefAliases ENUMERATED { neverDerefAliases (0), derefInSearching (1), derefFindingBaseObj (2), derefAlways (3) }, sizeLimit INTEGER (0 .. maxInt), timeLimit INTEGER (0 .. maxInt), typesOnly BOOLEAN, filter Filter, attributes AttributeTypeList, matchedOnly [0] BOOLEAN DEFAULT FALSE, sortKeys [1] SortKeyList OPTIONAL, reverseSort [2] BOOLEAN DEFAULT FALSE, modifyRightsReq [3] BOOLEAN DEFAULT FALSE, extraAttributes [4] BOOLEAN DEFAULT FALSE, attrSizeLimit [5] INTEGER OPTIONAL, subentries [6] BOOLEAN DEFAULT FALSE, dontUseCopy [7] BOOLEAN DEFAULT FALSE } SortKeyList ::= SEQUENCE SIZE (1..maxInt) OF SEQUENCE { attributeType AttributeType, orderingRule [0] MatchingRuleId OPTIONAL, startFrom [1] AssertionValue OPTIONAL, endWith [2] AssertionValue OPTIONAL } Filter ::= CHOICE { and [0] SET SIZE (1..maxInt) OF Filter, or [1] SET SIZE (1..maxInt) OF Filter, not [2] Filter, equalityMatch [3] AttributeValueAssertion, substrings [4] SubstringFilter, greaterOrEqual [5] AttributeValueAssertion, lessOrEqual [6] AttributeValueAssertion, present [7] AttributeType, approxMatch [8] AttributeValueAssertion, extensibleMatch [9] MatchingRuleAssertion } SubstringFilter ::= SEQUENCE { type AttributeType, substrings SEQUENCE SIZE (1..maxInt) OF CHOICE { initial [0] LDAPString, any [1] LDAPString, final [2] LDAPString } } MatchingRuleAssertion ::= SEQUENCE { matchingRules [1] SET SIZE (0..maxInt) OF MatchingRuleId, type [2] AttributeType, matchValue [3] AssertionValue, dnAttributes [4] BOOLEAN } SearchResultEntry ::= [APPLICATION 4] SEQUENCE { objectName LDAPDN, attributes PartialAttributeList, modifyRights [2] ModifyRights OPTIONAL, incompleteEntry [3] BOOLEAN DEFAULT FALSE, fromEntry [4] BOOLEAN DEFAULT FALSE } INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 PartialAttributeList ::= SEQUENCE SIZE (0..maxInt) OF SEQUENCE { type AttributeType, vals SET SIZE (0..maxInt) OF AttributeValue } SearchResultReference ::= [APPLICATION 18] Referral SearchResultDone ::= [APPLICATION 5] LDAPResult SearchResultFull ::= SEQUENCE SIZE (1..maxInt) OF CHOICE { entry SearchResultEntry, reference SearchResultReference, resultCode SearchResultDone } ModifyRights ::= SEQUENCE { entryRemove BOOLEAN, entryModifyDN BOOLEAN, attrRights SET SIZE (0..maxInt) OF SEQUENCE { type AttributeType, grantAdd BOOLEAN, grantRemove BOOLEAN } } ModifyRequest ::= [APPLICATION 6] SEQUENCE { object LDAPDN, modification SEQUENCE SIZE (1..maxInt) OF SEQUENCE { operation ENUMERATED { add (0), delete (1), replace (2) }, modification Attribute } } ModifyResponse ::= [APPLICATION 7] LDAPResult AddRequest ::= [APPLICATION 8] SEQUENCE { entry LDAPDN, attributes AttributeList } AttributeList ::= SEQUENCE SIZE (1..maxInt) OF SEQUENCE { type AttributeType, vals SET SIZE (1..maxInt) OF AttributeValue } AddResponse ::= [APPLICATION 9] LDAPResult DelRequest ::= [APPLICATION 10] LDAPDN DelResponse ::= [APPLICATION 11] LDAPResult INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 ModifyDNRequest ::= [APPLICATION 12] SEQUENCE { entry LDAPDN, newrdn RelativeLDAPDN, deleteoldrdn BOOLEAN, newSuperior [0] LDAPDN OPTIONAL } ModifyDNResponse ::= [APPLICATION 13] LDAPResult CompareRequest ::= [APPLICATION 14] SEQUENCE { entry LDAPDN, ava AttributeValueAssertion, timeLimit [0] INTEGER (0 .. maxInt) OPTIONAL, dontUseCopy [1] BOOLEAN DEFAULT FALSE } CompareResponse ::= [APPLICATION 15] LDAPResult AbandonRequest ::= [APPLICATION 16] MessageID ExtendedRequest ::= [APPLICATION 23] SEQUENCE { requestName [0] LDAPString, requestValue [1] OCTET STRING } ExtendedResponse ::= [APPLICATION 24] SEQUENCE { response [0] OCTET STRING OPTIONAL, standardResponse [1] LDAPResult } END Appendix B - Imported ASN.1 Definitions Note that the types described here are distinct from those defined in the body of this document. INTERNET-DRAFT Lightweight Directory Access Protocol 19 February 1996 B.1. Types from X.509(1993) "Authentication Framework" The type "Certificate" is defined in X.509(1993). It it strongly recommended that clients and server implementations which support certificates implement the draft addendums to X.509 which provide certificate extensions. AlgorithmIdentifier ::= SEQUENCE { algorithm OBJECT IDENTIFIER, parameters ANY OPTIONAL } CertificatePair ::= SEQUENCE { forward [0] Certificate OPTIONAL, reverse [1] Certificate OPTIONAL -- at least one of the pair shall be present -- } CertificationPath ::= SEQUENCE { userCertificate Certificate, theCACertificates SEQUENCE OF CertificatePair OPTIONAL } B.2. Types from X.511(1993) "Directory Abstract Syntax" The type "DistinguishedName" is defined in X.501(1993). It is the ASN.1 encoding, not a string encoding. Token ::= SIGNED { SEQUENCE { algorithm [0] AlgorithmIdentifier, name [1] DistinguishedName, time [2] UTCTime, random [3] BIT STRING } }