Network Working Group K. Zeilenga
Request for Comments: 3062 OpenLDAP Foundation
Category: Standards Track February 2001
LDAP PassWord Modify Extended Operation
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 (2001). All Rights Reserved.
Abstract
The integration of the Lightweight Directory Access Protocol (LDAP)
and external authentication services has introdUCed non-DN
authentication identities and allowed for non-directory storage of
passwords. As such, mechanisms which update the directory (e.g.,
Modify) cannot be used to change a user's password. This document
describes an LDAP extended operation to allow modification of user
passwords which is not dependent upon the form of the authentication
identity nor the password storage mechanism used.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", and "MAY" in this document are
to be interpreted as described in RFC2119.
1. Background and Intent of Use
Lightweight Directory Access Protocol (LDAP) [RFC2251] is designed to
support an number of authentication mechanisms including simple user
name/password pairs. Traditionally, LDAP users where identified by
the Distinguished Name [RFC2253] of a directory entry and this entry
contained a userPassword [RFC2256] attribute containing one or more
passwords.
The protocol does not mandate that passwords associated with a user
be stored in the directory server. The server may use any attribute
suitable for password storage (e.g., userPassword), or use non-
directory storage.
The integration [RFC2829] of application neutral SASL [RFC2222]
services which support simple username/password mechanisms (such as
DIGEST-MD5) has introduced non-LDAP DN authentication identity forms
and made storage of passwords the responsibility of the SASL service
provider.
LDAP update operations are designed to act upon attributes of an
entry within the directory. LDAP update operations cannot be used to
modify a user's password when the user is not represented by a DN,
does not have a entry, or when that password used by the server is
not stored as an attribute of an entry. An alternative mechanism is
needed.
This document describes an LDAP Extended Operation intended to allow
directory clients to update user passwords. The user may or may not
be associated with a directory entry. The user may or may not be
represented as an LDAP DN. The user's password may or may not be
stored in the directory.
The operation SHOULD NOT be used without adequate security protection
as the operation affords no privacy or integrity protect itself.
This operation SHALL NOT be used anonymously.
2. Password Modify Request and Response
The Password Modify operation is an LDAPv3 Extended Operation
[RFC2251, Section 4.12] and is identified by the OBJECT IDENTIFIER
passwdModifyOID. This section details the syntax of the protocol
request and response.
passwdModifyOID OBJECT IDENTIFIER ::= 1.3.6.1.4.1.4203.1.11.1
PasswdModifyRequestValue ::= SEQUENCE {
userIdentity [0] OCTET STRING OPTIONAL
oldPasswd [1] OCTET STRING OPTIONAL
newPasswd [2] OCTET STRING OPTIONAL }
PasswdModifyResponseValue ::= SEQUENCE {
genPasswd [0] OCTET STRING OPTIONAL }
2.1. Password Modify Request
A Password Modify request is an ExtendedRequest with the requestName
field containing passwdModifyOID OID and optionally provides a
requestValue field. If the requestValue field is provided, it SHALL
contain a PasswdModifyRequestValue with one or more fields present.
The userIdentity field, if present, SHALL contain an octet string
representation of the user associated with the request. This string
may or may not be an LDAPDN [RFC2253]. If no userIdentity field is
present, the request acts up upon the password of the user currently
associated with the LDAP session.
The oldPasswd field, if present, SHALL contain the user's current
password.
The newPasswd field, if present, SHALL contain the desired password
for this user.
2.2. Password Modify Response
A Password Modify response is an ExtendedResponse where the
responseName field is absent and the response field is optional. The
response field, if present, SHALL contain a PasswdModifyResponseValue
with genPasswd field present.
The genPasswd field, if present, SHALL contain a generated password
for the user.
If an resultCode other than success (0) is indicated in the response,
the response field MUST be absent.
3. Operation Requirements
Clients SHOULD NOT submit a Password Modification request without
ensuring adequate security safeguards are in place. Servers SHOULD
return a non-success resultCode if sufficient security protection are
not in place.
Servers SHOULD indicate their support for this extended operation by
providing PasswdModifyOID as a value of the supportedExtension
attribute type in their root DSE. A server MAY choose to advertise
this extension only when the client is authorized and/or has
established the necessary security protections to use this operation.
Clients SHOULD verify the server implements this extended operation
prior to attempting the operation by asserting the supportedExtension
attribute contains a value of PasswdModifyOID.
The server SHALL only return success upon successfully changing the
user's password. The server SHALL leave the password unmodified and
return a non-success resultCode otherwise.
If the server does not recognize provided fields or does not support
the combination of fields provided, it SHALL NOT change the user
password.
If oldPasswd is present and the provided value cannot be verified or
is incorrect, the server SHALL NOT change the user password. If
oldPasswd is not present, the server MAY use other policy to
determine whether or not to change the password.
The server SHALL NOT generate a password on behalf of the client if
the client has provided a newPasswd. In absence of a client provided
newPasswd, the server SHALL either generate a password on behalf of
the client or return a non-success result code. The server MUST
provide the generated password upon success as the value of the
genPasswd field.
The server MAY return adminLimitExceeded, busy,
confidentialityRequired, operationsError, unavailable,
unwillingToPerform, or other non-success resultCode as appropriate to
indicate that it was unable to successfully complete the operation.
Servers MAY implement administrative policies which restrict this
operation.
4. Security Considerations
This operation is used to modify user passwords. The operation
itself does not provide any security protection to ensure integrity
and/or confidentiality of the information. Use of this operation is
strongly discouraged when privacy protections are not in place to
guarantee confidentiality and may result in the disclosure of the
password to unauthorized parties. This extension MUST be used with
confidentiality protection, such as Start TLS [RFC2830]. The NULL
cipher suite MUST NOT be used.
5. Bibliography
[RFC2219] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC2119, March 1997.
[RFC2222] Myers, J., "Simple Authentication and Security Layer
(SASL)", RFC2222, October 1997.
[RFC2251] Wahl, M., Howes, T. and S. Kille, "Lightweight Directory
Access Protocol (v3)", RFC2251, December 1997.
[RFC2252] Wahl, M., Coulbeck, A., Howes, T. and S. Kille,
"Lightweight Directory Access Protocol (v3): Attribute
Syntax Definitions", RFC2252, December 1997.
[RFC2253] Wahl, M., Kille,S. and T. Howes, "Lightweight Directory
Access Protocol (v3): UTF-8 String Representation of
Distinguished Names", RFC2253, December 1997.
[RFC2256] Wahl, M., "A Summary of the X.500(96) User Schema for use
with LDAPv3", RFC2256, December 1997.
[RFC2829] Wahl, M., Alvestrand, H., Hodges, J. and R. Morgan,
"Authentication Methods for LDAP", RFC2829, May 2000.
[RFC2830] Hodges, J., Morgan, R. and M. Wahl, "Lightweight Directory
Access Protocol (v3): Extension for Transport Layer
Security", RFC2830, May 2000.
6. Acknowledgment
This document borrows from a number of IETF documents and is based
upon input from the IETF LDAPext working group.
7. Author's Address
Kurt D. Zeilenga
OpenLDAP Foundation
EMail: Kurt@OpenLDAP.org
8. Full Copyright Statement
Copyright (C) The Internet Society (2001). All Rights Reserved.
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