RFC2849: The LDAP Data Interchange Format (LDIF) - Technical Specification
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Related keywords:
(data interchange format)
(file)
(LDAP)
(LDIF)
(lightweight directory access protocol)
Network Working Group G. Good
Request for Comments: 2849 iPlanet e-commerce Solutions
Category: Standards Track June 2000
The LDAP Data Interchange Format (LDIF) - Technical Specification
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2000). All Rights Reserved.
Abstract
This document describes a file format suitable for describing
directory information or modifications made to directory information.
The file format, known as LDIF, for LDAP Data Interchange Format, is
typically used to import and export directory information between
LDAP-based directory servers, or to describe a set of changes which
are to be applied to a directory.
Background and Intended Usage
There are a number of situations where a common interchange format is
desirable. For example, one might wish to export a copy of the
contents of a directory server to a file, move that file to a
different machine, and import the contents into a second directory
server.
Additionally, by using a well-defined interchange format, development
of data import tools from legacy systems is facilitated. A fairly
simple set of tools written in awk or perl can, for example, convert
a database of personnel information into an LDIF file. This file can
then be imported into a directory server, regardless of the internal
database representation the target directory server uses.
The LDIF format was originally developed and used in the University
of Michigan LDAP implementation. The first use of LDIF was in
describing directory entries. Later, the format was expanded to
allow representation of changes to directory entries.
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RFC 2849 LDAP Data Interchange Format June 2000
Relationship to the application/directory MIME content-type:
The application/directory MIME content-type [1] is a general
framework and format for conveying directory information, and is
independent of any particular directory service. The LDIF format is
a simpler format which is perhaps easier to create, and may also be
used, as noted, to describe a set of changes to be applied to a
directory.
The key words "MUST", "MUST NOT", "MAY", "SHOULD", and "SHOULD NOT"
used in this document are to be interpreted as described in [7].
Definition of the LDAP Data Interchange Format
The LDIF format is used to convey directory information, or a
description of a set of changes made to directory entries. An LDIF
file consists of a series of records separated by line separators. A
record consists of a sequence of lines describing a directory entry,
or a sequence of lines describing a set of changes to a directory
entry. An LDIF file specifies a set of directory entries, or a set
of changes to be applied to directory entries, but not both.
There is a one-to-one correlation between LDAP operations that modify
the directory (add, delete, modify, and modrdn), and the types of
changerecords described below ("add", "delete", "modify", and
"modrdn" or "moddn"). This correspondence is intentional, and
permits a straightforward translation from LDIF changerecords to
protocol operations.
Formal Syntax Definition of LDIF
The following definition uses the augmented Backus-Naur Form
specified in RFC 2234 [2].
ldif-file = ldif-content / ldif-changes
ldif-content = version-spec 1*(1*SEP ldif-attrval-record)
ldif-changes = version-spec 1*(1*SEP ldif-change-record)
ldif-attrval-record = dn-spec SEP 1*attrval-spec
ldif-change-record = dn-spec SEP *control changerecord
version-spec = "version:" FILL version-number
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RFC 2849 LDAP Data Interchange Format June 2000
version-number = 1*DIGIT
; version-number MUST be "1" for the
; LDIF format described in this document.
dn-spec = "dn:" (FILL distinguishedName /
":" FILL base64-distinguishedName)
distinguishedName = SAFE-STRING
; a distinguished name, as defined in [3]
base64-distinguishedName = BASE64-UTF8-STRING
; a distinguishedName which has been base64
; encoded (see note 10, below)
rdn = SAFE-STRING
; a relative distinguished name, defined as
; <name-component> in [3]
base64-rdn = BASE64-UTF8-STRING
; an rdn which has been base64 encoded (see
; note 10, below)
control = "control:" FILL ldap-oid ; controlType
0*1(1*SPACE ("true" / "false")) ; criticality
0*1(value-spec) ; controlValue
SEP
; (See note 9, below)
ldap-oid = 1*DIGIT 0*1("." 1*DIGIT)
; An LDAPOID, as defined in [4]
attrval-spec = AttributeDescription value-spec SEP
value-spec = ":" ( FILL 0*1(SAFE-STRING) /
":" FILL (BASE64-STRING) /
"<" FILL url)
; See notes 7 and 8, below
url = <a Uniform Resource Locator,
as defined in [6]>
; (See Note 6, below)
AttributeDescription = AttributeType [";" options]
; Definition taken from [4]
AttributeType = ldap-oid / (ALPHA *(attr-type-chars))
options = option / (option ";" options)
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RFC 2849 LDAP Data Interchange Format June 2000
option = 1*opt-char
attr-type-chars = ALPHA / DIGIT / "-"
opt-char = attr-type-chars
changerecord = "changetype:" FILL
(change-add / change-delete /
change-modify / change-moddn)
change-add = "add" SEP 1*attrval-spec
change-delete = "delete" SEP
change-moddn = ("modrdn" / "moddn") SEP
"newrdn:" ( FILL rdn /
":" FILL base64-rdn) SEP
"deleteoldrdn:" FILL ("0" / "1") SEP
0*1("newsuperior:"
( FILL distinguishedName /
":" FILL base64-distinguishedName) SEP)
change-modify = "modify" SEP *mod-spec
mod-spec = ("add:" / "delete:" / "replace:")
FILL AttributeDescription SEP
*attrval-spec
"-" SEP
SPACE = %x20
; ASCII SP, space
FILL = *SPACE
SEP = (CR LF / LF)
CR = %x0D
; ASCII CR, carriage return
LF = %x0A
; ASCII LF, line feed
ALPHA = %x41-5A / %x61-7A
; A-Z / a-z
DIGIT = %x30-39
; 0-9
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RFC 2849 LDAP Data Interchange Format June 2000
UTF8-1 = %x80-BF
UTF8-2 = %xC0-DF UTF8-1
UTF8-3 = %xE0-EF 2UTF8-1
UTF8-4 = %xF0-F7 3UTF8-1
UTF8-5 = %xF8-FB 4UTF8-1
UTF8-6 = %xFC-FD 5UTF8-1
SAFE-CHAR = %x01-09 / %x0B-0C / %x0E-7F
; any value <= 127 decimal except NUL, LF,
; and CR
SAFE-INIT-CHAR = %x01-09 / %x0B-0C / %x0E-1F /
%x21-39 / %x3B / %x3D-7F
; any value <= 127 except NUL, LF, CR,
; SPACE, colon (":", ASCII 58 decimal)
; and less-than ("<" , ASCII 60 decimal)
SAFE-STRING = [SAFE-INIT-CHAR *SAFE-CHAR]
UTF8-CHAR = SAFE-CHAR / UTF8-2 / UTF8-3 /
UTF8-4 / UTF8-5 / UTF8-6
UTF8-STRING = *UTF8-CHAR
BASE64-UTF8-STRING = BASE64-STRING
; MUST be the base64 encoding of a
; UTF8-STRING
BASE64-CHAR = %x2B / %x2F / %x30-39 / %x3D / %x41-5A /
%x61-7A
; +, /, 0-9, =, A-Z, and a-z
; as specified in [5]
BASE64-STRING = [*(BASE64-CHAR)]
Notes on LDIF Syntax
1) For the LDIF format described in this document, the version
number MUST be "1". If the version number is absent,
implementations MAY choose to interpret the contents as an
older LDIF file format, supported by the University of
Michigan ldap-3.3 implementation [8].
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RFC 2849 LDAP Data Interchange Format June 2000
2) Any non-empty line, including comment lines, in an LDIF file
MAY be folded by inserting a line separator (SEP) and a SPACE.
Folding MUST NOT occur before the first character of the line.
In other words, folding a line into two lines, the first of
which is empty, is not permitted. Any line that begins with a
single space MUST be treated as a continuation of the previous
(non-empty) line. When joining folded lines, exactly one space
character at the beginning of each continued line must be
discarded. Implementations SHOULD NOT fold lines in the middle
of a multi-byte UTF-8 character.
3) Any line that begins with a pound-sign ("#", ASCII 35) is a
comment line, and MUST be ignored when parsing an LDIF file.
4) Any dn or rdn that contains characters other than those
defined as "SAFE-UTF8-CHAR", or begins with a character other
than those defined as "SAFE-INIT-UTF8-CHAR", above, MUST be
base-64 encoded. Other values MAY be base-64 encoded. Any
value that contains characters other than those defined as
"SAFE-CHAR", or begins with a character other than those
defined as "SAFE-INIT-CHAR", above, MUST be base-64 encoded.
Other values MAY be base-64 encoded.
5) When a zero-length attribute value is to be included directly
in an LDIF file, it MUST be represented as
AttributeDescription ":" FILL SEP. For example, "seeAlso:"
followed by a newline represents a zero-length "seeAlso"
attribute value. It is also permissible for the value
referred to by a URL to be of zero length.
6) When a URL is specified in an attrval-spec, the following
conventions apply:
a) Implementations SHOULD support the file:// URL format. The
contents of the referenced file are to be included verbatim
in the interpreted output of the LDIF file.
b) Implementations MAY support other URL formats. The
semantics associated with each supported URL will be
documented in an associated Applicability Statement.
7) Distinguished names, relative distinguished names, and
attribute values of DirectoryString syntax MUST be valid UTF-8
strings. Implementations that read LDIF MAY interpret files
in which these entities are stored in some other character set
encoding, but implementations MUST NOT generate LDIF content
which does not contain valid UTF-8 data.
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RFC 2849 LDAP Data Interchange Format June 2000
8) Values or distinguished names that end with SPACE SHOULD be
base-64 encoded.
9) When controls are included in an LDIF file, implementations
MAY choose to ignore some or all of them. This may be
necessary if the changes described in the LDIF file are being
sent on an LDAPv2 connection (LDAPv2 does not support
controls), or the particular controls are not supported by the
remote server. If the criticality of a control is "true", then
the implementation MUST either include the control, or MUST
NOT send the operation to a remote server.
10) When an attrval-spec, distinguishedName, or rdn is base64-
encoded, the encoding rules specified in [5] are used with the
following exceptions: a) The requirement that base64 output
streams must be represented as lines of no more than 76
characters is removed. Lines in LDIF files may only be folded
according to the folding rules described in note 2, above. b)
Base64 strings in [5] may contain characters other than those
defined in BASE64-CHAR, and are ignored. LDIF does not permit
any extraneous characters, other than those used for line
folding.
Examples of LDAP Data Interchange Format
Example 1: An simple LDAP file with two entries
version: 1
dn: cn=Barbara Jensen, ou=Product Development, dc=airius, dc=com
objectclass: top
objectclass: person
objectclass: organizationalPerson
cn: Barbara Jensen
cn: Barbara J Jensen
cn: Babs Jensen
sn: Jensen
uid: bjensen
telephonenumber: +1 408 555 1212
description: A big sailing fan.
dn: cn=Bjorn Jensen, ou=Accounting, dc=airius, dc=com
objectclass: top
objectclass: person
objectclass: organizationalPerson
cn: Bjorn Jensen
sn: Jensen
telephonenumber: +1 408 555 1212
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RFC 2849 LDAP Data Interchange Format June 2000
Example 2: A file containing an entry with a folded attribute value
version: 1
dn:cn=Barbara Jensen, ou=Product Development, dc=airius, dc=com
objectclass:top
objectclass:person
objectclass:organizationalPerson
cn:Barbara Jensen
cn:Barbara J Jensen
cn:Babs Jensen
sn:Jensen
uid:bjensen
telephonenumber:+1 408 555 1212
description:Babs is a big sailing fan, and travels extensively in sea
rch of perfect sailing conditions.
title:Product Manager, Rod and Reel Division
Example 3: A file containing a base-64-encoded value
version: 1
dn: cn=Gern Jensen, ou=Product Testing, dc=airius, dc=com
objectclass: top
objectclass: person
objectclass: organizationalPerson
cn: Gern Jensen
cn: Gern O Jensen
sn: Jensen
uid: gernj
telephonenumber: +1 408 555 1212
description:: V2hhdCBhIGNhcmVmdWwgcmVhZGVyIHlvdSBhcmUhICBUaGlzIHZhbHVl
IGlzIGJhc2UtNjQtZW5jb2RlZCBiZWNhdXNlIGl0IGhhcyBhIGNvbnRyb2wgY2hhcmFjdG
VyIGluIGl0IChhIENSKS4NICBCeSB0aGUgd2F5LCB5b3Ugc2hvdWxkIHJlYWxseSBnZXQg
b3V0IG1vcmUu
Example 4: A file containing an entries with UTF-8-encoded attribute
values, including language tags. Comments indicate the contents
of UTF-8-encoded attributes and distinguished names.
version: 1
dn:: b3U95Za25qWt6YOoLG89QWlyaXVz
# dn:: ou=<JapaneseOU>,o=Airius
objectclass: top
objectclass: organizationalUnit
ou:: 5Za25qWt6YOo
# ou:: <JapaneseOU>
ou;lang-ja:: 5Za25qWt6YOo
# ou;lang-ja:: <JapaneseOU>
ou;lang-ja;phonetic:: 44GI44GE44GO44KH44GG44G2
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RFC 2849 LDAP Data Interchange Format June 2000
# ou;lang-ja:: <JapaneseOU_in_phonetic_representation>
ou;lang-en: Sales
description: Japanese office
dn:: dWlkPXJvZ2FzYXdhcmEsb3U95Za25qWt6YOoLG89QWlyaXVz
# dn:: uid=<uid>,ou=<JapaneseOU>,o=Airius
userpassword: {SHA}O3HSv1MusyL4kTjP+HKI5uxuNoM=
objectclass: top
objectclass: person
objectclass: organizationalPerson
objectclass: inetOrgPerson
uid: rogasawara
mail: rogasawara@airius.co.jp
givenname;lang-ja:: 44Ot44OJ44OL44O8
# givenname;lang-ja:: <JapaneseGivenname>
sn;lang-ja:: 5bCP56yg5Y6f
# sn;lang-ja:: <JapaneseSn>
cn;lang-ja:: 5bCP56yg5Y6fIOODreODieODi+ODvA==
# cn;lang-ja:: <JapaneseCn>
title;lang-ja:: 5Za25qWt6YOoIOmDqOmVtw==
# title;lang-ja:: <JapaneseTitle>
preferredlanguage: ja
givenname:: 44Ot44OJ44OL44O8
# givenname:: <JapaneseGivenname>
sn:: 5bCP56yg5Y6f
# sn:: <JapaneseSn>
cn:: 5bCP56yg5Y6fIOODreODieODi+ODvA==
# cn:: <JapaneseCn>
title:: 5Za25qWt6YOoIOmDqOmVtw==
# title:: <JapaneseTitle>
givenname;lang-ja;phonetic:: 44KN44Gp44Gr44O8
# givenname;lang-ja;phonetic::
<JapaneseGivenname_in_phonetic_representation_kana>
sn;lang-ja;phonetic:: 44GK44GM44GV44KP44KJ
# sn;lang-ja;phonetic:: <JapaneseSn_in_phonetic_representation_kana>
cn;lang-ja;phonetic:: 44GK44GM44GV44KP44KJIOOCjeOBqeOBq+ODvA==
# cn;lang-ja;phonetic:: <JapaneseCn_in_phonetic_representation_kana>
title;lang-ja;phonetic:: 44GI44GE44GO44KH44GG44G2IOOBtuOBoeOCh+OBhg==
# title;lang-ja;phonetic::
# <JapaneseTitle_in_phonetic_representation_kana>
givenname;lang-en: Rodney
sn;lang-en: Ogasawara
cn;lang-en: Rodney Ogasawara
title;lang-en: Sales, Director
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RFC 2849 LDAP Data Interchange Format June 2000
Example 5: A file containing a reference to an external file
version: 1
dn: cn=Horatio Jensen, ou=Product Testing, dc=airius, dc=com
objectclass: top
objectclass: person
objectclass: organizationalPerson
cn: Horatio Jensen
cn: Horatio N Jensen
sn: Jensen
uid: hjensen
telephonenumber: +1 408 555 1212
jpegphoto:< file:///usr/local/directory/photos/hjensen.jpg
Example 6: A file containing a series of change records and comments
version: 1
# Add a new entry
dn: cn=Fiona Jensen, ou=Marketing, dc=airius, dc=com
changetype: add
objectclass: top
objectclass: person
objectclass: organizationalPerson
cn: Fiona Jensen
sn: Jensen
uid: fiona
telephonenumber: +1 408 555 1212
jpegphoto:< file:///usr/local/directory/photos/fiona.jpg
# Delete an existing entry
dn: cn=Robert Jensen, ou=Marketing, dc=airius, dc=com
changetype: delete
# Modify an entry's relative distinguished name
dn: cn=Paul Jensen, ou=Product Development, dc=airius, dc=com
changetype: modrdn
newrdn: cn=Paula Jensen
deleteoldrdn: 1
# Rename an entry and move all of its children to a new location in
# the directory tree (only implemented by LDAPv3 servers).
dn: ou=PD Accountants, ou=Product Development, dc=airius, dc=com
changetype: modrdn
newrdn: ou=Product Development Accountants
deleteoldrdn: 0
newsuperior: ou=Accounting, dc=airius, dc=com
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RFC 2849 LDAP Data Interchange Format June 2000
# Modify an entry: add an additional value to the postaladdress
# attribute, completely delete the description attribute, replace
# the telephonenumber attribute with two values, and delete a specific
# value from the facsimiletelephonenumber attribute
dn: cn=Paula Jensen, ou=Product Development, dc=airius, dc=com
changetype: modify
add: postaladdress
postaladdress: 123 Anystreet $ Sunnyvale, CA $ 94086
-
delete: description
-
replace: telephonenumber
telephonenumber: +1 408 555 1234
telephonenumber: +1 408 555 5678
-
delete: facsimiletelephonenumber
facsimiletelephonenumber: +1 408 555 9876
-
# Modify an entry: replace the postaladdress attribute with an empty
# set of values (which will cause the attribute to be removed), and
# delete the entire description attribute. Note that the first will
# always succeed, while the second will only succeed if at least
# one value for the description attribute is present.
dn: cn=Ingrid Jensen, ou=Product Support, dc=airius, dc=com
changetype: modify
replace: postaladdress
-
delete: description
-
Example 7: An LDIF file containing a change record with a control
version: 1
# Delete an entry. The operation will attach the LDAPv3
# Tree Delete Control defined in [9]. The criticality
# field is "true" and the controlValue field is
# absent, as required by [9].
dn: ou=Product Development, dc=airius, dc=com
control: 1.2.840.113556.1.4.805 true
changetype: delete
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RFC 2849 LDAP Data Interchange Format June 2000
Security Considerations
Given typical directory applications, an LDIF file is likely to
contain sensitive personal data. Appropriate measures should be
taken to protect the privacy of those persons whose data is contained
in an LDIF file.
Since ":<" directives can cause external content to be included when
processing an LDIF file, one should be cautious of accepting LDIF
files from external sources. A "trojan" LDIF file could name a file
with sensitive contents and cause it to be included in a directory
entry, which a hostile entity could read via LDAP.
LDIF does not provide any method for carrying authentication
information with an LDIF file. Users of LDIF files must take care to
verify the integrity of an LDIF file received from an external
source.
Acknowledgments
The LDAP Interchange Format was developed as part of the University
of Michigan LDAP reference implementation, and was developed by Tim
Howes, Mark Smith, and Gordon Good. It is based in part upon work
supported by the National Science Foundation under Grant No. NCR-
9416667.
Members of the IETF LDAP Extensions Working group provided many
helpful suggestions. In particular, Hallvard B. Furuseth of the
University of Oslo made many significant contributions to this
document, including a thorough review and rewrite of the BNF.
References
[1] Howes, T. and M. Smith, "A MIME Content-Type for Directory
Information", RFC 2425, September 1998.
[2] Crocker, D., and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", RFC 2234, November 1997.
[3] Wahl, M., Kille, S. and T. Howes, "A String Representation of
Distinguished Names", RFC 2253, December 1997.
[4] Wahl, M., Howes, T. and S. Kille, "Lightweight Directory Access
Protocol (v3)", RFC 2251, July 1997.
[5] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message Bodies",
RFC 2045, November 1996.
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RFC 2849 LDAP Data Interchange Format June 2000
[6] Berners-Lee, T., Masinter, L. and M. McCahill, "Uniform
Resource Locators (URL)", RFC 1738, December 1994.
[7] Bradner, S., "Key Words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[8] The SLAPD and SLURPD Administrators Guide. University of
Michigan, April 1996. <URL:
http://www.umich.edu/~dirsvcs/ldap/doc/guides/slapd/toc.html>
[9] M. P. Armijo, "Tree Delete Control", Work in Progress.
Author's Address
Gordon Good
iPlanet e-commerce Solutions
150 Network Circle
Mailstop USCA17-201
Santa Clara, CA 95054, USA
Phone: +1 408 276 4351
EMail: ggood@netscape.com
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RFC 2849 LDAP Data Interchange Format June 2000
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