Re: [OAUTH-WG] [JAR] scope parameter outside request object of OIDC request

[Takahiko Kawasaki <[e-mail]>]

Hi Vladimir,

Just FYI. To be exact, FAPI (version 1) Part 1 (Read-Only) does not require
all request parameters be put duplicately in a request object. It is FAPI
(version 1) Part 2 (Read-Write) (Section 5.2.2
<https://openid.net/specs/openid-financial-api-part-2-ID2.html#authorization-server>
Clause 10) that has the requirement. In the context of FAPI Part 1, a
request object does not have to be used. One more note is that parameters
inside a request object and parameters outside a request object are merged
(as they are in OIDC Core 1.0) when the authorization request is being made
for FAPI Read-Only APIs (not for FAPI Read-Write APIs).

Taka


On Thu, Sep 24, 2020 at 7:14 PM Vladimir Dzhuvinov <[e-mail]>
wrote:

> Hi Taka,
>
> Speaking of the OIDC Core 1.0 conformance tests, IMO those should not
> change with the publication of JAR.
>
> Speaking of the FAPI 1.0 tests, those already require all request
> parameters to be JWT-secured, which makes the requests also JAR compliant:
> all parameters are found in the JWT, with scope (as complete scope or
> minimally required scope=openid), response_type, client_id and redirect_uri
> also having a copy outside the JWT, as query parameters. Thus the request
> is OIDC as well as JAR compliant.
>
> If I had an RP I would always construct OIDC auth requests like that, to
> make sure they comply with OIDC as well as the new JAR spec (and will not
> have issues with servers which implement both specs but are not able to
> "switch" behavior for some reason).
>
> Vladimir
> On 23/09/2020 14:58, Takahiko Kawasaki wrote:
>
> Hi Vladimir,
>
> Thank you for your reply. It sounds that your opinion is "`scope` request
> parameter must exist outside the request object even if JAR applies if the
> authorization request is an OIDC request". I'm on the fence on this topic
> and just wondered whether those who had wanted to remove `response_type`
> outside the request object (although doing it was a breaking change) would
> want to remove `scope` outside the request object too with the same
> motivation (although I don't remember well what was the motivation). JAR
> dares to drop `response_type`, so it would not be surprising to see that
> JAR dares to drop `scope` (including `openid`) too.
>
> OIDC Core 1.0 requires `response_type`, but JAR allows omission of the
> parameter if the parameter is included in the request object.
>
> If we applied the same logic, we would be able to state:
>
> OIDC Core 1.0 requires `scope` (including `openid`), but JAR allows
> omission of the parameter if the parameter is included in the request
> object.
>
> In terms of `response_type`, practically speaking, JAR has modified OIDC
> Core 1.0. Because JAR has already been allowed to go so far as that point,
> I would say it is difficult to find a convincing reason not to allow
> omission of `scope`.
>
> AFAIK, in the context of OIDC Core 1.0, parameters that are required to
> exist outside a request object even if they are included in the request
> object are `client_id`, `response_type` and `scope`. Because `client_id` is
> mandatory in JAR (it has become mandatory after long discussion),
> discussion for the parameter is not needed. Because the community has
> already reached consensus that `response_type` can be omitted, discussion
> for the parameter is not needed, either. What I've brought here is
> discussion for `scope`, hopefully the last parameter that is affected by
> JAR.
>
> Again, I'm on the fence on this topic. However, because logical conclusion
> (at least of mine) is that JAR should allow omission of `scope` (it also
> should be noted that JAR's basic rule prohibits referring to request
> parameters outside a request object), I want to see explicit consensus if
> `scope` (including `openid`) outside a request object is still required
> even after JAR is enabled.
>
> In short, my question is "Should `scope` be omitted?" I guess that the
> conclusion will affect the official conformance suite.
>
> Best Regards,
> Takahiko Kawasaki
> Authlete, Inc.
>
>
>
> On Tue, Sep 22, 2020 at 5:59 AM Vladimir Dzhuvinov <
> [e-mail]> wrote:
>
>> Hi Taka,
>> On 21/09/2020 20:12, Takahiko Kawasaki wrote:
>>
>> If we allow JAR (JWT Secured Authorization Request) to relax the
>> requirement of `response_type` request parameter (outside a request object)
>> from mandatory to optional, should we relax the following requirement of
>> `scope` request parameter stated in OIDC Core 1.0 Section 6.1, too?
>>
>> ----------
>> Even if a scope parameter is present in the Request Object value, a scope
>> parameter MUST always be passed using the OAuth 2.0 request syntax
>> containing the openid scope value to indicate to the underlying OAuth 2.0
>> logic that this is an OpenID Connect request.
>> ----------
>>
>> Otherwise, an authorization request like
>> "client_id=...&request(_uri)=..." fails if the request object represents an
>> OIDC request. An authorization request has to look like
>> "client_id=...&request(_uri)=...&scope=openid" (`scope` including `openid`
>> has to be given) even if the authorization server conforms to JAR and
>> allows omission of `response_type` request parameter.
>>
>> The bottom of section 5 has normative text which allows a JAR compliant
>> server to also comply with the OIDC spec with its own style of request /
>> request_uri parameter handling insofar as to not reject other query params
>> (such as scope, etc). The difference is that according to JAR their values
>> cannot be used or merged (as in OIDC). But what can be reasonably done is
>> to detect scope=openid as you say and then switch to OIDC style request
>> object behavior.
>>
>> https://tools.ietf.org/html/draft-ietf-oauth-jwsreq-30#section-5
>>
>>    The client MAY send the parameters included in the request object
>>    duplicated in the query parameters as well for the backward
>>    compatibility etc.  However, the authorization server supporting this
>>    specification MUST only use the parameters included in the request
>>    object.
>>
>> The confusion between the two specs clears when it's seen that the
>> request objects in OIDC and JAR have different objectives.
>>
>> In OIDC the objective is to enable securing of selected parameters.
>>
>> In JAR the objective is to secure the entire authz request.
>>
>>
>>
>> I think that implementers want to know consensus on this because it
>> affects implementations. Has this been discussed yet?
>>
>> Best Regards,
>> Takahiko Kawasaki
>> Authlete, Inc.
>>
>>
>> Vladimir
>>
>
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