So, where should we take it to? Just add back client_id as it used to be? On Fri, Jan 24, 2020 at 6:55 AM John Bradley <ve7...@ve7jtb.com> wrote:
> > ---------- Forwarded message --------- > From: John Bradley <ve7...@ve7jtb.com> > Date: Sat, Jan 18, 2020, 9:31 PM > Subject: Re: [OAUTH-WG] [EXTERNAL] Re: JWT Secured Authorization Request > (JAR) vs OIDC request object > To: Benjamin Kaduk <ka...@mit.edu> > > > If you put the iss in the JWE header it is integrity protected, as JWE > only supports AAD encryption algs. > > It is more of a problem when the client is sending a requestURI in that > case having the clientID in the GET to the Authorization endpoint is useful. > > I think there is a argument for explicitly allowing the clientID as long > as it exactly matches the clientID in the JAR. > > John B. > > On Fri, Jan 17, 2020 at 11:53 PM Benjamin Kaduk <ka...@mit.edu> wrote: > >> On Fri, Jan 17, 2020 at 08:44:18AM -0500, Justin Richer wrote: >> > I don’t agree with this stance from a security or implementation >> perspective. >> > >> > If there’s a clear order of precedence for the information, it’s not >> particularly problematic. Everything inside the request object is to be >> taken over things outside the request object. We have the exact same >> semantics and process with dynamic registration, where the software >> statement is carried alongside plain JSON claims, and the two are mixed >> with a very simple algorithm: >> > >> > - If a field is inside the signed payload, use that value and ignore >> any copy of it on the outside >> > - If a field is not inside the signed payload and is outside the >> signed payload, use the outside value >> > >> > Can someone please point out a concrete security issue with this >> algorithm? This is the extent of the “merge” semantics that we need here, >> and it would solve not only the ability to use this for use cases that call >> for a more static request object (perhaps signed by a third party and not >> the client) along side the plain parameters that can vary, but also the >> backwards compatibility issue that’s been discussed. With this algorithm in >> place, you could have OIDC clients actually be compliant with the spec, >> since OIDC requires replication of the values inside the request object on >> the outside with exact matches. An OIDC server wouldn’t be fully compliant >> with the new spec since it would reject some compliant JAR requests that >> are missing the external parameters, but that’s fairly easy logic to add on >> the OIDC side. And in that case you get a matrix of compatibility like: >> >> I agree that the merge algorithm is simple and fairly straightforward to >> implement. But, as Joseph has been alluding, it's only simple if you've >> already made the decision to use all the parameters, both from inside and >> from outside the signed payload. The security risk lies about having to >> make the trust decision twice, more than the mundane details of actually >> doing the merge. (Though there is still some latent risk, given that >> we've >> seen some really crazy quality of implementation out there.) >> >> It's certainly *possible* that things end up fine in many well-deliniated >> cases where merging can be used. But it's more complicated to reason >> about, and I don't remmber seeing much previous discussion about the >> specifics of the double trust decision. >> >> -Ben >> >> > >> > JAR Server | OIDC Server | >> > ------------+------------+--------------+ >> > JAR Client | YES | NO | >> > OIDC Client | YES | YES | >> > >> > Breaking one out of the four possible combinations in a very >> predictable way is, I think, the best way to handle backwards compatibility >> here. >> > >> > But between this issue and JAR’s problematic call for the value of a >> request_uri to always be a JWT and be fetchable by the AS (neither of which >> are true in the case of PAR) makes me think we need to pull this back and >> rework those things, in a push back to the IESG’s comments. >> > >> > — Justin >> > >> > >> > > On Jan 16, 2020, at 7:38 PM, Joseph Heenan <jos...@authlete.com> >> wrote: >> > > >> > > I agree with this, particularly the security concerns of merging. If >> we merge, we can much guarantee there will eventually be a security issue >> where an attacker is able to gain an advantage by adding a parameter to the >> url query (which the server would then happily process if that parameter >> isn’t found inside the request object). Ruling out that case makes security >> analysis (particularly when creating new OAuth2 parameters) significantly >> simpler. >> > > >> > > Putting the iss in the JWE header and having the client_id duplicated >> outside the request object seem to address all the concerns I’ve seen >> raised. >> > > >> > > (It seems like it may be unnecessary to have the client_id duplicated >> outside if the request_uri is a PAR one though.) >> > > >> > > Joseph >> > > >> > > >> > > >> > >> On 16 Jan 2020, at 22:40, John Bradley <ve7...@ve7jtb.com> wrote: >> > >> >> > >> I agree with the IESG reasoning that merging is problimatic. Once we >> > >> allow that given a unknown list of possible paramaters with diffrent >> > >> security properties it would be quite difficult to specify safely. >> > >> >> > >> Query paramaters can still be sent outside the JAR, but if they are >> in >> > >> the OAuth registry the AS MUST ignore them. >> > >> >> > >> Puting the iss in the JWE headder addresses the encryption issue >> without >> > >> merging. >> > >> >> > >> I understand that some existing servers have dependencys on getting >> the >> > >> clientID as a query paramater. >> > >> >> > >> Is that the only paramater that people have a issue with as oposed >> to a >> > >> nice to have? >> > >> >> > >> Would allowing the AS to not ignore the clientID as a query >> paramater as >> > >> long as it matches the one inside the JAR, basicly the same as >> Connect >> > >> request object but for just the one paramater make life easier for >> the >> > >> servers? >> > >> >> > >> I am not promising a change but gathering info before proposing >> something. >> > >> >> > >> John B. >> > >> >> > >> >> > >> On 1/16/2020 1:53 AM, Benjamin Kaduk wrote: >> > >>> On Wed, Jan 15, 2020 at 11:02:33PM +0200, Vladimir Dzhuvinov wrote: >> > >>>> On 14/01/2020 19:20, Takahiko Kawasaki wrote: >> > >>>>> Well, embedding a client_id claim in the JWE header in order to >> > >>>>> achieve "request parameters outside the request object should not >> be >> > >>>>> referred to" is like "putting the cart before the horse". Why do >> we >> > >>>>> have to avoid using the traditional client_id request parameter so >> > >>>>> stubbornly? >> > >>>>> >> > >>>>> The last paragraph of Section 3.2.1 >> > >>>>> <https://tools.ietf.org/html/rfc6749#section-3.2.1> of RFC 6749 >> says >> > >>>>> as follows. >> > >>>>> >> > >>>>> /A client MAY use the "client_id" request parameter to identify >> > >>>>> itself when sending requests to the token endpoint. In the >> > >>>>> "authorization_code" "grant_type" request to the token endpoint, >> > >>>>> *an unauthenticated client MUST send its "client_id" to prevent >> > >>>>> itself from inadvertently accepting a code intended for a client >> > >>>>> with a different "client_id".* This protects the client from >> > >>>>> substitution of the authentication code. (It provides no >> > >>>>> additional security for the protected resource.)/ >> > >>>>> >> > >>>>> >> > >>>>> If the same reasoning applies, a client_id must always be sent >> with >> > >>>>> request / request_uri because client authentication is not >> performed >> > >>>>> at the authorization endpoint. In other words, */an >> unauthenticated >> > >>>>> client (every client is unauthenticated at the authorization >> endpoint) >> > >>>>> MUST send its "client_id" to prevent itself from inadvertently >> > >>>>> accepting a request object for a client with a different >> "client_id"./* >> > >>>>> >> > >>>> Identifying the client in JAR request_uri requests can be really >> useful >> > >>>> so that an AS which requires request_uri registration to prevent >> DDoS >> > >>>> attacks and other checks can do those without having to index all >> > >>>> request_uris individually. I mentioned this before. >> > >>>> >> > >>>> I really wonder what the reasoning of the IESG reviewers was to >> insist >> > >>>> on no params outside the JAR JWT / request_uri. >> > >>>> >> > >>>> I'm beginning to realise this step of the review process isn't >> > >>>> particularly transparent to WG members. >> > >>> Could you expand on that a bit more? My understanding is that the >> IESG >> > >>> ballot mail gets copied to the WG precisely so that there is >> transparency, >> > >>> e.g., the thread starting at >> > >>> >> https://mailarchive.ietf.org/arch/msg/oauth/lkOhwiDj_hCI55BQRdiR9R0JwgI >> > >>> Which admittely is from almost three years ago, but that's the >> earliest >> > >>> that I found that could be seen as the source of this behavior. >> > >>> >> > >>> -Ben >> > >>> >> > >>> P.S. some other discussion at >> > >>> >> https://mailarchive.ietf.org/arch/msg/oauth/-tUrNY1X9eI_tQGI8T-IGx4xHy8 >> and >> > >>> >> https://mailarchive.ietf.org/arch/msg/oauth/Uke1nxRlgx62EJLevZgpWCz_UwY >> and >> > >>> so on. >> > >>> >> > >>> _______________________________________________ >> > >>> OAuth mailing list >> > >>> OAuth@ietf.org >> > >>> https://www.ietf.org/mailman/listinfo/oauth >> > >> >> > >> _______________________________________________ >> > >> OAuth mailing list >> > >> OAuth@ietf.org >> > >> https://www.ietf.org/mailman/listinfo/oauth >> > > >> > > _______________________________________________ >> > > OAuth mailing list >> > > OAuth@ietf.org >> > > https://www.ietf.org/mailman/listinfo/oauth >> > >> >> > _______________________________________________ >> > OAuth mailing list >> > OAuth@ietf.org >> > https://www.ietf.org/mailman/listinfo/oauth >> >> _______________________________________________ >> OAuth mailing list >> OAuth@ietf.org >> https://www.ietf.org/mailman/listinfo/oauth >> > _______________________________________________ > OAuth mailing list > OAuth@ietf.org > https://www.ietf.org/mailman/listinfo/oauth > -- Nat Sakimura (=nat) Chairman, OpenID Foundation http://nat.sakimura.org/ @_nat_en
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