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

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/.

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This Internet-Draft will expire on September 15, 2011.

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Table of Contents

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:

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 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].

     POST /revoke HTTP/1.1
     Host: server.example.com
     Content-Type: application/x-www-form-urlencoded

     token=45ghiukldjahdnhzdauz&
     client_id=s6BhdRkqt3&client_secret=gX1fBat3bV
				    

For example, a client may request the revocation of a refresh token with the following request (line breaks are for display purposes only):

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 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 Stübner, 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. References

[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.
[I-D.ietf-oauth-v2] Hammer-Lahav, E, Recordon, D and D Hardt, "The OAuth 2.0 Authorization Protocol", Internet-Draft draft-ietf-oauth-v2-22, September 2011.

Authors' Addresses

Dr.-Ing. Torsten Lodderstedt editor Deutsche Telekom AG EMail: torsten@lodderstedt.net
Stefanie Dronia SYRACOM Consulting AG EMail: sdronia@gmx.de