One document matched: draft-ietf-asid-ldapv3-protocol-00.txt
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)
<draft-ietf-asid-ldapv3-protocol-00.txt>
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.
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- 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.
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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
<CN=Mark Wahl, O=ISODE Consortium, C=GB>
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.
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- 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.
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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.
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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
<distinguished-name> ::= <name>
<relative-distinguished-name> ::= <name-component>
where <name> and <name-component> 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
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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.
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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 }
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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:
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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 }
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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.
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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.
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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:
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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),
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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:
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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", <draft-ietf-asid-ldapv3-attributes-00.txt>,
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,
<draft-ietf-asid-ldap-format-03.txt>
[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),
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-- 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 } }
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