Network Working Group K. Zeilenga
Request for Comments: 4532 OpenLDAP Foundation
Category: Standards Track June 2006
Lightweight Directory Access Protocol (LDAP)
"Who am I?" 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 (C) The Internet Society (2006).
This specification provides a mechanism for Lightweight Directory
Access Protocol (LDAP) clients to obtain the authorization identity
the server has associated with the user or application entity. This
mechanism is specified as an LDAP extended operation called the LDAP
"Who am I?" operation.
1. Background and Intent of Use
This specification describes a Lightweight Directory Access Protocol
(LDAP) [RFC4510] operation that clients can use to obtain the primary
authorization identity, in its primary form, that the server has
associated with the user or application entity. The operation is
called the "Who am I?" operation.
This specification is intended to replace the existing Authorization
Identity Controls [RFC3829] mechanism, which uses Bind request and
response controls to request and return the authorization identity.
Bind controls are not protected by security layers established by the
Bind operation that includes them. While it is possible to establish
security layers using StartTLS [RFC4511][RFC4513] prior to the Bind
operation, it is often desirable to use security layers established
by the Bind operation. An extended operation sent after a Bind
operation is protected by the security layers established by the Bind
Zeilenga Standards Track [Page 1]RFC 4532 LDAP "Who am I?" Operation June 2006
There are other cases where it is desirable to request the
authorization identity that the server associated with the client
separately from the Bind operation. For example, the "Who am I?"
operation can be augmented with a Proxied Authorization Control
[RFC4370] to determine the authorization identity that the server
associates with the identity asserted in the Proxied Authorization
Control. The "Who am I?" operation can also be used prior to the
Servers often associate multiple authorization identities with the
client, and each authorization identity may be represented by
multiple authzId [RFC4513] strings. This operation requests and
returns the authzId that the server considers primary. In the
specification, the term "the authorization identity" and "the
authzId" are generally to be read as "the primary authorization
identity" and the "the primary authzId", respectively.
1.1. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in BCP 14 [RFC2119].
2. The "Who am I?" Operation
The "Who am I?" operation is defined as an LDAP Extended Operation
[RFC4511] identified by the whoamiOID Object Identifier (OID). This
section details the syntax of the operation's whoami request and
whoamiOID ::= "126.96.36.199.4.1.4188.8.131.52"
2.1. The whoami Request
The whoami request is an ExtendedRequest with a requestName field
containing the whoamiOID OID and an absent requestValue field. For
example, a whoami request could be encoded as the sequence of octets
30 1e 02 01 02 77 19 80 17 31 2e 33 2e 36 2e 31
2e 34 2e 31 2e 34 32 30 33 2e 31 2e 31 31 2e 33
Zeilenga Standards Track [Page 2]RFC 4532 LDAP "Who am I?" Operation June 20062.2. The whoami Response
The whoami response is an ExtendedResponse where the responseName
field is absent and the response field, if present, is empty or an