[OAUTH-WG] Fwd: [EXTERNAL] Re: JWT Secured Authorization Request (JAR) vs OIDC request object

John Bradley <ve7jtb@ve7jtb.com> Thu, 23 January 2020 21:55 UTC

Return-Path: <ve7jtb@ve7jtb.com>
X-Original-To: oauth@ietfa.amsl.com
Delivered-To: oauth@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 5263512011D for <oauth@ietfa.amsl.com>; Thu, 23 Jan 2020 13:55:21 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.898
X-Spam-Level:
X-Spam-Status: No, score=-1.898 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=ve7jtb-com.20150623.gappssmtp.com
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id pNqIcVz5JVa4 for <oauth@ietfa.amsl.com>; Thu, 23 Jan 2020 13:55:17 -0800 (PST)
Received: from mail-wm1-x331.google.com (mail-wm1-x331.google.com [IPv6:2a00:1450:4864:20::331]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id DDA9912011C for <oauth@ietf.org>; Thu, 23 Jan 2020 13:55:16 -0800 (PST)
Received: by mail-wm1-x331.google.com with SMTP id t14so4186170wmi.5 for <oauth@ietf.org>; Thu, 23 Jan 2020 13:55:16 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ve7jtb-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=YAbB1jEVg8rVUC5QpSgmk/hHzlIaWXrx4XDTx7NG9NA=; b=xqmReFq/M461I+yAwUcAhZiiqI8m7dF7EGkuAaQw+6s1UEFZJrpu44hl6uio0FvSrt Pug9f8DqgwFw5njTvqDhzvXwpuroylVmRh8KFQ02A7GlLOq0ZfzvN5UAfcFz8ubXkmjq F7o7hBFoiaOCVaiW2gwBIgYzCDjIJ+UKPTS+0nMhGsLnFVCvczLGFuNA+80FBc9ZPFXC 915JjwIVjySfPB1Ylzh4bJQAij0e8x6CWAjXeL5ErdrFsjmpWZzcXZe9du2Ndb/D2vB8 wNdSXa+sem8waP9xOohFlgB2o401LuhjSZL189SKJqk/JnPKM4PdSTfOP+rjod0oUrvU kyiQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=YAbB1jEVg8rVUC5QpSgmk/hHzlIaWXrx4XDTx7NG9NA=; b=LCZnQwxeYtGnLvfWscA2ekruUnr7OKnKSpaXi4ruVhidFIpm7TR4b4oLxpj1MTsk2G BguHtrbJ4bt5dS2x2BscBLx8hAzqFKXYcS8VRM9solKbzcoXFo/0vsJ4OJVbxkuHwQA1 5h972UimHg5QhChNTQ26uELwD/lzNHoJ2wPx9P78xFdBfRM+ZHBSd9ql1ObTHdeCNIzK ztMRhF4Lq1lPzPHPXaFO/SbKKgBEiRHbFfXnuKl6sVBYtFWxy8ULgHFQ+J083y0IIncP EH/h3q0f8xFpGHumfSOFoTg78g1sstT3Rvjwq6G0HPsTOaTMD+478BbV3DDXOW8wOSqt vhKg==
X-Gm-Message-State: APjAAAVKmHiO2KX/mvNZw4C9P3vNdpHfba+ZTCjlw9ttCRlW1bvp2t0k 5Ivsged8yjvrF+jSr45/aZrhl3BtE1arJh2I8Oc+zilh9Ks=
X-Google-Smtp-Source: APXvYqyqZ2wd34VFMteVHHLHFLbAUHYzvfRxL25eeKjjZLCbkw9mt1opukFPxJPmKH1oqAUwYM0qn6PjjRW6aJh7iRk=
X-Received: by 2002:a1c:4c5:: with SMTP id 188mr65866wme.82.1579816514644; Thu, 23 Jan 2020 13:55:14 -0800 (PST)
MIME-Version: 1.0
References: <CAANoGhJB4mYSFiWKt3T=cObH7uCW0s3Zpv2m92+YaAY2Oy4mqw@mail.gmail.com> <2aca5c38-bb20-497e-14ed-f4a9245a9439@connect2id.com> <7baae999-47c1-f749-6c51-f45022ab1a3d@ve7jtb.com> <3d9ffc74-6c9c-48a1-0c98-65a7465e8dbc@connect2id.com> <CAHdPCmNHeUyDjrc32oQPZ5g3oars-XY3vq2p3qt2LzzkZMTw5w@mail.gmail.com> <89345e9b-8191-f01d-71a6-453ec197796f@connect2id.com> <20200116045302.GG80030@kduck.mit.edu> <837c8db5-5200-29c6-5914-167b77bdc071@ve7jtb.com> <9DAC4E16-2A60-4B86-B1FA-B59B097E8F78@authlete.com> <D6837D1F-01B6-4B46-8DF7-41969BE96112@mit.edu> <20200118025320.GV80030@kduck.mit.edu> <CAANoGhKtgqob_7AmFJ-OfROSx7QopehFdKAx8qmR8rUdzLNWPA@mail.gmail.com>
In-Reply-To: <CAANoGhKtgqob_7AmFJ-OfROSx7QopehFdKAx8qmR8rUdzLNWPA@mail.gmail.com>
From: John Bradley <ve7jtb@ve7jtb.com>
Date: Thu, 23 Jan 2020 18:55:04 -0300
Message-ID: <CAANoGhJgz6QC8rTwXH4Fik9bRydFDuAJB3Kpvoj3j1MCX2CZOw@mail.gmail.com>
To: oauth@ietf.org
Content-Type: multipart/alternative; boundary="0000000000002a85f1059cd5b285"
Archived-At: <https://mailarchive.ietf.org/arch/msg/oauth/YDL8XvIb7jtJfWs73vRiE-W3zUo>
Subject: [OAUTH-WG] Fwd: [EXTERNAL] Re: JWT Secured Authorization Request (JAR) vs OIDC request object
X-BeenThere: oauth@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: OAUTH WG <oauth.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/oauth>, <mailto:oauth-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/oauth/>
List-Post: <mailto:oauth@ietf.org>
List-Help: <mailto:oauth-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/oauth>, <mailto:oauth-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 23 Jan 2020 21:55:22 -0000

---------- Forwarded message ---------
From: John Bradley <ve7jtb@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 <kaduk@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 <kaduk@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 <joseph@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 <ve7jtb@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
>