Re: [OAUTH-WG] draft-bertocci-oauth-access-token-jwt-00

[Brian Campbell <[e-mail]>]

I'm not sure I understand what you mean but this document would reference
the RFC 7519 claims and, if needed, futher profile their usage for access
tokens.

On Thu, Apr 4, 2019 at 9:39 AM Hans Zandbelt <[e-mail]>
wrote:

> agreed but it (i.e. "sub") also brings us back to where we started
>
> Hans.
>
> On Thu, Apr 4, 2019 at 5:27 PM Brian Campbell <bcampbell=
> [e-mail]> wrote:
>
>> The same is true for most of the other main claims too - iss, exp, aud,
>> sub, iat, etc.. They are defined in RFC 7519 not OIDC.
>>
>> On Thu, Apr 4, 2019 at 9:21 AM Brian Campbell <[e-mail]>
>> wrote:
>>
>>> Yeah, OpenID.Core isn't the right reference for `aud`.
>>> https://tools.ietf.org/html/rfc7519#section-4.1.3 is the definition of
>>> `aud` which should be the reference and this document can provide
>>> additional specifics for the given application.
>>>
>>> On Thu, Apr 4, 2019 at 8:07 AM George Fletcher <gffletch=
>>> [e-mail]> wrote:
>>>
>>>> Another comment...
>>>>
>>>>    aud  REQUIRED - as defined in section 2 of [OpenID.Core <https://tools.ietf.org/html/draft-bertocci-oauth-access-token-jwt-00#ref-OpenID.Core>].  See
>>>>       Section 3 <https://tools.ietf.org/html/draft-bertocci-oauth-access-token-jwt-00#section-3> for indications on how an authorization server should
>>>>       determine the value of aud depending on the request.  [Note: some
>>>>       vendors seem to rely on resource aliases.  If we believe this to
>>>>       be a valuable feature, here's some proposed language: The aud
>>>>       claim MAY include a list of individual resource indicators if they
>>>>       are all aliases referring to the same requested resource known by
>>>>       the authorization server. ]
>>>>
>>>>
>>>>
>>>> I don't think OpenID.Core Section 3 is the correct reference for
>>>> determining the 'aud' value. The issue here is that the 'aud' of the
>>>> id_token is the recipient of the id_token (i.e. the client). However, for
>>>> access_tokens the 'aud' value should be the resource service that will
>>>> receive the access_token. There is no existing guidance for this and we
>>>> should provide such guidance as this is "kind of new" for OAuth2 (from an
>>>> explicit specification perspective).
>>>>
>>>> Also, there is the concept of 'azp' from the id_token which amounts to
>>>> "who's allowed to present this token" which might be interesting from the
>>>> case where one entity obtains the token, and gives it to another entity to
>>>> present. Not sure if we want to include this concept or not.
>>>>
>>>> Finally, I think we may need some best practice around how the concept
>>>> of audience and resource should be managed. For instance...
>>>>
>>>>    If the request does not include a resource parameter, the
>>>>    authorization server MUST use in the aud claim a default resource
>>>>    indicator.  If a scope parameter is present in the request, the
>>>>    authorization server SHOULD use it to infer the value of the default
>>>>    resource indicator to be used in the aud claim.
>>>>
>>>>
>>>> I think for most implementations this would amount to... define an
>>>> audience that covers all the resource services where the access token can
>>>> be returned and set that as the audience (e.g. urn:x-mydomain:apis). Which
>>>> is perfectly legal but maybe not in the spirit of the spec:) I am receiving
>>>> feedback from developers that binding access tokens narrowly to the
>>>> resource where they will be presented is concerning from a chattiness
>>>> perspective (latency issues) and general load on the deployed AS
>>>> infrastructure.
>>>>
>>>> On 3/24/19 7:29 PM, Vittorio Bertocci wrote:
>>>>
>>>> Dear all,
>>>> I just submitted a draft describing a JWT profile for OAuth 2.0 access
>>>> tokens. You can find it in
>>>> https://datatracker.ietf.org/doc/draft-bertocci-oauth-access-token-jwt/
>>>> .
>>>> I have a slot to discuss this tomorrow at IETF 104 (I'll be presenting
>>>> remotely). I look forward for your comments!
>>>>
>>>> Here's just a bit of backstory, in case you are interested in how this
>>>> doc came to be. The trajectory it followed is somewhat unusual.
>>>>
>>>>    - Despite OAuth2 not requiring any specific format for ATs, through
>>>>    the years I have come across multiple proprietary solution using JWT for
>>>>    their access token. The intent and scenarios addressed by those solutions
>>>>    are mostly the same across vendors, but the syntax and interpretations in
>>>>    the implementations are different enough to prevent developers from reusing
>>>>    code and skills when moving from product to product.
>>>>    - I asked several individuals from key products and services to
>>>>    share with me concrete examples of their JWT access tokens (THANK YOU
>>>>    Dominick Baier (IdentityServer), Brian Campbell (PingIdentity),
>>>>    Daniel Dobalian (Microsoft), Karl Guinness (Okta) for the tokens and
>>>>    explanations!).
>>>>    I studied and compared all those instances, identifying
>>>>    commonalities and differences.
>>>>    - I put together a presentation summarizing my findings and
>>>>    suggesting a rough interoperable profile (slides:
>>>>    https://sec.uni-stuttgart.de/_media/events/osw2019/slides/bertocci_-_a_jwt_profile_for_ats.pptx
>>>>    <https://sec..uni-stuttgart.de/_media/events/osw2019/slides/bertocci_-_a_jwt_profile_for_ats.pptx>
>>>>    ) - got early feedback from Filip Skokan on it. Thx Filip!
>>>>    - The presentation was followed up by 1.5 hours of unconference
>>>>    discussion, which was incredibly valuable to get tight-loop feedback and
>>>>    incorporate new ideas. John Bradley, Brian Campbell Vladimir Dzhuvinov,
>>>>    Torsten Lodderstedt, Nat Sakimura, Hannes Tschofenig were all there
>>>>    and contributed generously to the discussion. Thank you!!!
>>>>    Note: if you were at OSW2019, participated in the discussion and
>>>>    didn't get credited in the draft, my apologies: please send me a note and
>>>>    I'll make things right at the next update.
>>>>    - On my flight back I did my best to incorporate all the ideas and
>>>>    feedback in a draft, which will be discussed at IETF104 tomorrow. Rifaat,
>>>>    Hannes and above all Brian were all super helpful in negotiating the
>>>>    mysterious syntax of the RFC format and submission process.
>>>>
>>>> I was blown away by the availability, involvement and willingness to
>>>> invest time to get things right that everyone demonstrated in the process.
>>>> This is an amazing community.
>>>> V.
>>>>
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