Re: [OAUTH-WG] OAuth 2.0 Discovery Location

George Fletcher <> Thu, 25 February 2016 15:27 UTC

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To: Vladimir Dzhuvinov <>,
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From: George Fletcher <>
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Date: Thu, 25 Feb 2016 10:27:53 -0500
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Subject: Re: [OAUTH-WG] OAuth 2.0 Discovery Location
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That said, I'm not against the AS informing the client that the token 
can be used at the MailResource, ContactResource and MessagingResource 
to help the client know not to send the token to a BlogResource. 
However, identifying the actual endpoint seems overly complex when what 
is really trying to be protected is a token from being used where it 
shouldn't be (which is solved by Pop)


On 2/25/16 10:25 AM, George Fletcher wrote:
> Interesting... this is not at all my current experience:) If a RS goes 
> from v2 of it's API to v3 and that RS uses the current standard of 
> putting a "v2" or"v3" in it's API path... then a token issued for v2 
> of the API can not be sent to v3 of the API, because v3 wasn't wasn't 
> registered/deployed when the token was issued.
> The constant management of scopes to URI endpoints seems like a 
> complexity that will quickly get out of hand.
> Thanks,
> George
> On 2/25/16 2:22 AM, Vladimir Dzhuvinov wrote:
>> On 25/02/16 09:02, Manger, James wrote:
>>>> I'm concerned that forcing the AS to know about all RS's endpoints that will accept it's tokens creates a very brittle deployment architecture
>>> The AS is issuing temporary credentials (access_tokens) to clients but doesn’t know where those credentials will work? That’s broken.
>>> An AS should absolutely indicate where an access_token can be used. draft-sakimura-oauth-meta suggests indicating this with 1 or more “ruri” (resource URI) values in an HTTP Link header. A better approach would be including a list of web origins in the token response beside the access_token field.
>> +1
>> This will appear more consistent with the current experience, and 
>> OAuth does allow the token response JSON object to be extended with 
>> additional members (as it's done in OpenID Connect already).
>> Cheers,
>> Vladimir
>>> --
>>> James Manger
>>> From: OAuth [] On Behalf Of George Fletcher
>>> Sent: Thursday, 25 February 2016 6:17 AM
>>> To: Phil Hunt<>; Nat Sakimura<>
>>> Cc:<>  <>
>>> Subject: Re: [OAUTH-WG] OAuth 2.0 Discovery Location
>>> I'm concerned that forcing the AS to know about all RS's endpoints that will accept it's tokens creates a very brittle deployment architecture. What if a RS moves to a new endpoint? All clients would be required to get new tokens (if I understand correctly). And the RS move would have to coordinate with the AS to make sure all the timing is perfect in the switch over of endpoints.
>>> I suspect a common deployment architecture today is that each RS requires one or more scopes to access it's resources. The client then asks the user to authorize a token with a requested list of scopes. The client can then send the token to the appropriate RS endpoint. The RS will not authorize access unless the token has the required scopes.
>>> If the concern is that the client may accidentally send the token to a "bad" RS which will then replay the token, then I'd rather use a PoP mechanism because the point is that you want to ensure the correct client is presenting the token. Trying to ensure the client doesn't send the token to the wrong endpoint seems fraught with problems.
>>> Thanks,
>>> George
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