Open Authentication Protocol T. Lodderstedt, Ed.
Internet-Draft Deutsche Telekom AG
Intended status: Standards Track S. Dronia
Expires: September 15, 2011 SYRACOM Consulting AG
March 14, 2011
Token Revocation
draft-lodderstedt-oauth-revocation-02
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. Normative References . . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 5
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1. Introduction
The current OAuth 2.0 draft [I-D.ietf-oauth-v2] defines several ways
for a client to obtain refresh and access tokens. This specification
supplements the draft with a mechanism to revoke both types of tokens
and facilitates the following use cases:
o The end-user triggers revocation from within the client that sends
the appropriate revocation request to the autorization server.
From the end-user's perspective, this looks like a "logout" or
"reset" function. The request causes the removal of the client
permissions associated with the particular token to access the
end-user's protected resources. This use case makes it even more
comfortable to the end-user to revoke his access grant immediately
via the client.
o In contrast to revocation by a client, the authorization server
(or a related entity) may offer its end-users a self-care portal
to delete access grants given to clients independent of any token
storing devices. Such a portal offers the possibility to an end-
user to look at and revoke all access grants he once authorized.
In cases the token storing device is not available, e.g. it is
lost or stolen, revocation by a self-care portal is the only
possibility to limit or avoid abuse.
In the end, security, usability, and ease of use are increased by
token revocation.
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 MAY be supported.
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. 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
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mechanisms.
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.
Note: the authorization server is supposed to detect the
token type automatically.
The client also includes its authentication credentials as described
in Section 3 of [I-D.ietf-oauth-v2].
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&
client_id=s6BhdRkqt3&client_secret=gX1fBat3bV
The authorization server first validates the client credentials (if
present) and verifies whether the client is authorized to revoke the
particular token based on the client identity 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
MUST NOT make any assumptions 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 200. 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 5.2. of [I-D.ietf-oauth-v2]. The
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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.
3. Acknowledgements
We would like to thank Sebastian Ebling, Christian Stuebner, Brian
Campbell, Igor Faynberg, Lukas Rosenstock, Marius Scurtescu, and
Justin P. Richer 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. Normative References
[I-D.ietf-oauth-v2]
Hammer-Lahav, E., Recordon, D., and D. Hardt, "The OAuth
2.0 Authorization Protocol", draft-ietf-oauth-v2-13 (work
in progress), February 2011.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008.
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Authors' Addresses
Dr.-Ing. Torsten Lodderstedt (editor)
Deutsche Telekom AG
Email: torsten@lodderstedt.net
Stefanie Dronia
SYRACOM Consulting AG
Email: sdronia@gmx.de
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