Open Authentication Protocol T. Lodderstedt
Internet-Draft Deutsche Telekom AG
Intended status: Standards Track September 8, 2010
Expires: March 12, 2011
Token Revocation
draft-lodderstedt-oauth-revocation-00
Abstract
This draft proposes an additional endpoint for OAuth authorization
servers for revoking tokens.
Status of this Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Token Revocation . . . . . . . . . . . . . . . . . . . . . . . 3
3. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
6. Informative References . . . . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 5
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1. Introduction
The current OAuth 2.0 draft [draft-ietf-oauth-v2-10] defines several
ways for a client to obtain refresh and access tokens. This
specification supplements the draft with a mechanism to finalize the
life cycle of both types of tokens. From an end user's perspective,
this mechanism is used to realize application logout or the removal
of a persistent application's permission to access the user's
resources.
By using an additional endpoint, the token revocation endpoint,
clients can request the revocation of a particular token. Compliant
implementation must support the revocation of refresh tokens, access
token revocation is an optional feature.
2. Token Revocation
The client requests the revocation of a particular token by making an
HTTP "POST" request to the token revocation endpoint. The location
of the token revocation endpoint can be found in the authorization
servers documentation, or can be obtained by using [[OAuth Discovery
]]. The token endpoint URI MAY include a query component.
Since requests to the token revocation endpoint result in the
transmission of plain text credentials in the HTTP request, the
authorization server MUST require the use of a transport-layer
security mechanism when sending requests to the token revocation
endpoints. Authorization servers MUST support TLS 1.2 as defined in
[RFC5246], and MAY support additional transport-layer security
mechanisms.
The client authenticates with the authorization server by adding its
client credentials to the request as described in Section 2 of
[draft-ietf-oauth-v2-10].
The client constructs the request by including the following
parameters using the "application/x-www-form-urlencoded" format in
the HTTP request entity-body:
token REQUIRED. The token that the client wants to get revoked.
token_type REQUIRED. The type of the token to be revoked, either
"refresh_token" or "access_token". Information about the
supported token types can be found in the authorization
server's documentation, or can be obtained by using [[OAuth
Discovery ]].
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For example, a client may request the revocation of a refresh token
with the following request (line breaks are for display purposes
only):
POST /revoke HTTP/1.1
Host: server.example.com
Content-Type: application/x-www-form-urlencoded
token=45ghiukldjahdnhzdauz&token_type=refresh_token&
client_id=s6BhdRkqt3&client_secret=gX1fBat3bV
The authorization server first verifies whether the client is
authorized to revoke the particular token based on the client
credentials and its policy. For example, only the client the token
has been issued for might be allowed to revoke it. It is also
conceivable to allow a dedicated user self-care portal to revoke all
kinds of tokens.
In the next step, the authorization server invalidates the token.
Whether the revocation takes effect instantly or with some delay
depends on the architecture of the particular deployment. The client
shall not make any assumption about the timing and MUST NOT use the
token again.
If the processed token is a refresh token and the authorization
server supports the revocation of access tokens, then the
authorization server must also invalidate all access tokens issued
for that refresh token.
The authorization server indicates a successful processing of the
request by a HTTP status code 204. Status code 401 indicates a
failed client authentication, whereas a status code 403 is used if
the client is not authorized to revoke the particular token. For all
other error conditions, a status code 400 is used along with an error
response as defined in section 4.3. of [draft-ietf-oauth-v2-10]. The
following error codes are defined for the token revocation endpoint:
unsupported_token_type The authorization server does not support the
revocation of the presented token type. i.e. the client tried
to revoke an access token on a server not supporting this
feature.
invalid_token The presented token is invalid.
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3. Acknowledgements
I would like to thank Stefanie Dronia, Sebastian Ebling, and
Christian Stuebner for their valuable feedback.
4. IANA Considerations
This draft includes no request to IANA.
5. Security Considerations
All relevant security considerations have been given in the
functional specification.
6. Informative References
[draft-ietf-oauth-v2-10]
Hammer-Lahav, E., Ed., Recordon, D., and D. Hardt, "The
OAuth 2.0 Protocol draft-ietf-oauth-v2-10", July 2010,
<http://tools.ietf.org/html/draft-ietf-oauth-v2-10>.
Author's Address
Dr.-Ing. Torsten Lodderstedt
Deutsche Telekom AG
Email: torsten@lodderstedt.net
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