draft-lodderstedt-oauth-revocation.txt

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.

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

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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-v2-20 (work
              in progress), July 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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