Re: [OAUTH-WG] draft-ietf-oauth-revocation-04 Review

[Torsten Lodderstedt <[e-mail]>]

Hi Tony,

thanks for your review comments.

*** @Justin: thanks for jumping in. ***

I would like to recap the results of the discussion so far and propose 
some changes.

Am 24.01.2013 00:54, schrieb Anthony Nadalin:
>
> Review:
>
> 1.Since not stated I assume that the Revocation Endpoint can exist on 
> a different server from the Authorization server (or is it assumed 
> that they are 1), if so how is the Revocation Endpoint found?
>

Having read your arguments I realize the current text is a bit specific 
about the means to obtain the endpoint location (as it does not mention 
other means).

current text:

The location of
    the token revocation endpoint can be found in the authorization
    server's documentation.  The token endpoint URI MAY include a query
    component.


proposal:

The means to obtain the location of the revocation endpoint is out of scope of this specification.

There is a range of options. The client could, for example,
automatically discover this information (along with other server
andpoints and properties). Alternatively, the client developer could
also get to know the endpoint location from the server's documentation.

Note: As this endpoint is handling security sensible credentials, such information must be obtained from a trustworthy resource.


> 2.Any token type that is supported can be revoked, including refresh 
> token ?
>

The draft currently explicitly states support for access and refresh 
tokens. Do you want the draft to be weaker at this point and to allow 
for the revocation of any token?

> 3.Why does one have to send the token, can't this just be an auth_code ?
>

The draft is intended to support token revocation. I agree with Justin. 
Authz codes are short duration and one time use. I don't see a need to 
revoke them. I also don't see the need to use them to revoke the 
respective access token indirectly.

> 4.Says CORS SHOULD be supported, I think a MAY be better here since a 
> site may have issues supporting CORS
>

I'm fine with MAY since I tend to see CORS as an optional feature. What 
do others think?

> 5.Does not say but is the revocation to be immediate upon the return 
> of the request ?
>

The client must assume the revocation is immediate upon the return of 
the request. I could explicitly express this in the text

current text

In the next step, the authorization server invalidates the token.
    The client MUST NOT use this token again after revocation.


Proposal

   In the next step, the authorization server invalidates the token. The
client must assume the revocation is immediate upon the return of the
request. The client MUST NOT use the token again after the revocation.


> 6.Does the revocation of the access token also revoke the refresh 
> token (if it was provided) ? Or is this a revocation policy decision ?
>

As described by Justin, there are two use cases:

- if the token passed to the request is a refresh token and the server 
supports access token revocation, the server SHOULD also revoke them.
- if the token passed to the request is an access token, the server may 
decide to revoke the respective refresh token as well.

I think every client must be prepared to cope with "sudden" invalidation 
of any token type. So having different server policies with respect to 
related tokens shouldn't create interop problems.

What changes would you expect?

> 7.Section 2 says "the client MUST NOT use this token again", well that 
> seems odd, not sure this should be here as the client could try to use 
> it gain, there is no need to put support in client to prevent this.
>

The client should discard the token immediately after revocation.

regards.
Torsten.
>
>
>
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