Re: [OAUTH-WG] JWT - scope claim missing

[Nat Sakimura <[e-mail]>]

No. I am not confusing scope with audience.

There is no standard scope. So, the scope has to be either defined by the
resource or the authorization server.
Just stating scope is too vague that you will not able to find out whose
scope it is.

That is why I wrote that the scope has to be understood in the context of
aud.
Audience is the resource. So what I wrote amounts to be that the scope
expressed in the token is what was defined by the resource and not the
authorization server.

It could be authorization server's scope, but then there would be a
complication that the resource has to be able to resolve that to its own
scope. Expressing the scope as the audience's scope will free us from this
problem.

Nat

=nat via iPhone

Mar 11, 2013 10:38、Lewis Adam-CAL022 <[e-mail]>
のメッセージ:

  I would not even want to confuse audience with scope.  Maybe in the
simplest of cases, where there is a one-to-one mapping between scope and
audience, but in reality the RS could expose multiple APIs at the same
endpoint.  Granted the RS could extract the audience field based on a fully
qualified scope, but it just seems that claims, scopes, and audiences are
each unique and should be kept that way.



adam



*From:* Phil Hunt [mailto:[e-mail] <[e-mail]>]
*Sent:* Monday, March 11, 2013 9:25 AM
*To:* Nat Sakimura
*Cc:* Lewis Adam-CAL022; [e-mail] WG
*Subject:* Re: [OAUTH-WG] JWT - scope claim missing



One thing that concerns me is that scope is very different from a claim. An
claim is an assertion provided that may have some level of dispute/quality
etc.



A scope defines what is request or what has been authorized.  It's an
absolute thing. Therefore it is not a claim. Audience...maybe.



This is why I think scope deserves special attention/discussion in
authorization assertions and in access tokens.



Phil



@independentid

www.independentid.com

[e-mail]







On 2013-03-10, at 9:17 PM, Nat Sakimura wrote:



 So, it is soooo late in the game: I have been completely underwater to
even read the OAuth mails for about a month and slowly catching up now.



Here is an I-D that I have created partly in response to the RS-AS
interaction piece that was talked about at IETF 85.

It does not have 'scope' and has 'claims' instead as it was based on OpenID
Connect, but it is easy to add, provided that the scopes are to be
understood as that of the 'aud'.



http://tools.ietf.org/id/draft-sakimura-oidc-structured-token-01.txt



Best,



Nat



2013/3/1 Lewis Adam-CAL022 <[e-mail]>

Hmmm, I’m not so sure.  It depends where we all think OAuth is on its
trajectory.  On one hand, OAuth has already seen an insanely massive amount
of deployment.  On the other hand, RESTful APIs see no sign of slowing
down.   Now I’m not going to go so far as Craig B. and say that everything
and everyone will be API enabled in the future, but it sure is going to be
a lot.  That being said, one could argue that even with all the OAuth
implementation we’ve seen, that this is just the infancy of it.  Obviously
a WG profile of a JWT-structured AT could not deprecate other forms
(unstructured, SAML, etc.) but going forward new developers may choose to
embrace this, and in fact this could even be the guidance.   I agree with
previous comments that Justin’s introspection draft might be a good place
to explore this.



adam



*From:* Brian Campbell [mailto:[e-mail]]
*Sent:* Thursday, February 28, 2013 1:36 PM
*To:* Lewis Adam-CAL022
*Cc:* John Bradley; [e-mail] WG


*Subject:* Re: [OAUTH-WG] JWT - scope claim missing





I do agree that a WG profile of a JWT-structured access token could lend
itself to interoperability and ultimately be a useful thing. But you are
right that there already are many implementations out there in the wild
(heck, I've written one myself) and that might make it difficult to
standardize on something.

Because of that, and many other reasons, I don't want to try and add that
to existing assertion drafts.



On Thu, Feb 28, 2013 at 12:13 PM, Lewis Adam-CAL022 <
[e-mail]> wrote:

Hi Brian, a few thoughts from somebody outside of the WG …



As a newcomer to OAuth last year, I was initially confused by the titles.
It was confusing because we have SAML bearer **assertions** and JWT bearer *
*tokens** … and as John just (begrudgingly) stated in this thread, the JWT
is being used as an assertion in this profile (and in OIDC).  I think it
will be difficult to find a good name for these profiles since they do two
entirely different things (e.g. define a new grant type and define a new
method of client authentication).  One could argue that as long as the WG
is at it, then why not add a third section to the JWT profile, which talks
about usage of JWT-structured bearer access tokens: it would not be any
less related than the other two focuses of the doc.  Then the document
could be called something simple like “profiles of JWT usage in OAuth” or
something like that.



On one hand, it is probably naïve to think that an access token can be
standardized in a profile given how many have already been released into
the wild, but on the other hand, a WG profile of a JWT-structured access
token could lend itself to interoperability, where AS implementations can
advertise conformance to the profile and who knows … maybe the RS’s of the
future will be good with this.



adam



*From:* [e-mail] [mailto:[e-mail]] *On Behalf
Of *Brian Campbell
*Sent:* Thursday, February 28, 2013 1:03 PM
*To:* John Bradley
*Cc:* [e-mail] WG


*Subject:* Re: [OAUTH-WG] JWT - scope claim missing



I'm not sure anyone really "picked" the titles for the bearer token
profiles. They just kind of evolved. And evolved in funny ways especially
when client authn to the AS was added.

You won't hear me argue that the titles are "good" and this is not the
first time there's been confusion about what they actually do. They define
new grant types and new client authentication methods. They *do not* define
an access token format or anything else about access tokens. JWT and SAML
could be used for that but that's not what these drafts do.

Suggestions for better title(s) would be more than welcome.



Here's what they are now:


SAML 2.0 Bearer Assertion Profiles for OAuth 2.0
draft-ietf-oauth-saml2-bearer

JSON Web Token (JWT) Bearer Token Profiles for OAuth 2.0
draft-ietf-oauth-jwt-bearer

Assertion Framework for OAuth 2.0
draft-ietf-oauth-assertions



On Thu, Feb 28, 2013 at 11:36 AM, John Bradley <[e-mail]> wrote:

Yes the title likely adds to the confusion given that the bearer tokens are
not access tokens.



Things as separate from OAuth as the Firefox browerID spec use JWS signed
JWTs.



The bearer token profiles for OAuth 2 are for OAuth2.



The JSON Web Token
(JWT)<http://tools.ietf.org/html/draft-ietf-oauth-json-web-token-06>
spec
did not start in OAuth and is not OAuth specific.



A JWT is:

JSON Web Token (JWT)  A string representing a set of claims as a JSON

      object that is encoded in a JWS or JWE, enabling the claims to be

      digitally signed or MACed and/or encrypted.



So OAuth or other profiles may define claims to go in a JWT, but the JWT
needs to itself only define the claims necessary for security processing.



John B.

PS that was a soft ball If you hadn't responded I would have been
disappointed.  I din't pick the title for the bearer token profiles.





On 2013-02-28, at 10:12 AM, Phil Hunt <[e-mail]> wrote:


 JSON Web Token (JWT) Bearer Token Profiles for OAuth 2.0


Note the title says "for OAuth2"



Sorry. Couldn't resist.



Phil



Sent from my phone.


On 2013-02-28, at 9:40, John Bradley <[e-mail]> wrote:

JWT is an assertion( I am probably going to regret using that word).



It is used in openID connect for id_tokens, it is used in OAuth for
Assertion grant types and authentication of the client to the token
endpoint.

http://tools.ietf.org/html/draft-ietf-oauth-jwt-bearer-04







JSON Web Token (JWT) Bearer Token Profiles for OAuth 2.0



Dosen't define JWT's use for access tokens for the RS.



Bottom line JWT is for more than access tokens.



John B.



On 2013-02-28, at 9:28 AM, Phil Hunt <[e-mail]> wrote:



Are you saying jwt is not an access token type?

Phil



Sent from my phone.


On 2013-02-28, at 8:58, John Bradley <[e-mail]> wrote:

Yes, defining scope in JWT is the wrong place.   JWT needs to stick to the
security claims needed to process JWT.



I also don't know how far you get requiring a specific authorization format
for JWT, some AS will wan to use a opaque reference, some might want to use
a user claim or role claim, others may use scopes,  combining scopes and
claims is also possible.



Right now it is up to a AS RS pair to agree on how to communicate
authorization.   I don't want MAC to be more restrictive than bearer when
it comes to authorization between AS and RS.



Hannes wanted to know why JWT didn't define scope.  The simple answer is
that it is out of scope for JWT itself.   It might be defined in a OAuth
access token profile for JWT but it should not be specific to MAC.



John B.

On 2013-02-28, at 8:44 AM, Brian Campbell <[e-mail]>
wrote:



I think John's point was more that scope is something rather specific to an
OAuth access token and, while JWT is can be used to represent an access
token, it's not the only application of JWT. The 'standard' claims in JWT
are those that are believed (right or wrong) to be widely applicable across
different applications of JWT. One could argue about it but scope is
probably not one of those.

It would probably make sense to try and build a profile of JWT specifically
for OAuth access tokens (though I suspect there are some turtles and
dragons in there), which might be the appropriate place to define/register
a scope claim.



On Thu, Feb 28, 2013 at 9:24 AM, Phil Hunt <[e-mail]> wrote:

Are you advocating TWO systems? That seems like a bad choice.

I would rather fix scope than go to a two system approach.

Phil

Sent from my phone.

On 2013-02-28, at 8:17, John Bradley <[e-mail]> wrote:

> While scope is one method that a AS could communicate authorization to a
RS, it is not the only or perhaps even the most likely one.
> Using scope requires a relatively tight binding between the RS and AS,
 UMA uses a different mechanism that describes finer grained operations.
> The AS may include roles, user, or other more abstract claims that the
the client may (god help them) pass on to EXCML for processing.
>
> While having a scopes claim is possible, like any other claim it is not
part of the JWT core security processing claims, and needs to be defined by
extension.
>
> John B.
> On 2013-02-28, at 2:29 AM, Hannes Tschofenig <[e-mail]>
wrote:
>
>> Hi Mike,
>>
>> when I worked on the MAC specification I noticed that the JWT does not
have a claim for the scope. I believe that this would be needed to allow
the resource server to verify whether the scope the authorization server
authorized is indeed what the client is asking for.
>>
>> Ciao
>> Hannes
>>
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-- 
Nat Sakimura (=nat)

Chairman, OpenID Foundation
http://nat.sakimura.org/
@_nat_en

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