Hi Dave, either a type check or a lookup for client_id together with absence of sub are going to be new logic- the latter seems to be more economical in term of moving parts, without loss of expressive power. I am not really committed to one model or the other, I just want to capture the approach that gets the most consensus. Let's see if more people/products chime in with perspectives on this
On Tue, Mar 26, 2019 at 9:57 AM Dave Tonge <dave.to...@momentumft.co.uk> wrote: > Hi Vittorio > > My understanding from Rob and others is that `sub` is already used for > tokens issued via the client credentials grant (in fact looking at the > tables from your presentation, most examples used `sub` for both user > identity and client identity). Given the desire for a spec that doesn't > break existing implementations, perhaps a new claim indicating the type of > access token would allow for better interoperability. > > Dave > > On Tue, 26 Mar 2019 at 17:48, Vittorio Bertocci <Vittorio= > 40auth0....@dmarc.ietf.org> wrote: > >> thank you Steinar and everyone else for the comments on this! >> To summarize the situation so far: Dominick, Steinar, Rob, David, Nov, >> Bertrand recommend using sub only for users. Martin would like to have the >> sub for app only flows as well. Hans is neutral. >> That does sound like the sub as user has more consensus, tho before >> changing it I'd wait for the people currently at IETF104 to have more time >> to comment as well. >> Clarification. If the goal is to be able to apply the logic "if there's a >> sub, it's a user flow", we have to explicitly disallow (MUST NOT) the use >> of sub when that's not the case. Are all OK with it? >> >> Dave, the suggestion of having explicit typing for app only vs user only >> is interesting! For the purpose of putting together an interoperable >> profile, tho, I would suggest we table it for v1 in the interest of getting >> to something easy to adopt (hence with small delta vs existing >> implementations) faster. >> >> On Tue, Mar 26, 2019 at 1:40 AM Steinar Noem <stei...@udelt.no> wrote: >> >>> Hi Vittorio, we (the national federation-gateway for the health >>> services in norway - "HelseID") think his is a really valuable initiative! >>> We also agree with Dominick concerning definition of the "sub" claim. >>> >>> <mvh>Steinar</mvh> >>> >>> tir. 26. mar. 2019 kl. 07:25 skrev Dominick Baier < >>> dba...@leastprivilege.com>: >>> >>>> From an access token consumer (aka API) developer point of view, I >>>> prefer this logic >>>> >>>> "If sub is present - client acts on behalf of a user, if not - not." >>>> >>>> Anything more complicated has a potential of going wrong. >>>> >>>> >>>> On 26. March 2019 at 01:34:53, Nov Matake (mat...@gmail.com) wrote: >>>> >>>> Hi Vittorio, >>>> >>>> Yeah, I’m concerning user & client ids collision. >>>> I haven’t seen such implementations, but user-select username as sub, >>>> or incremental integer as sub & client_id will be easily collide. >>>> >>>> If you can enforce collision resistant IDs between user & client >>>> instances, it’ll works fine. I feel its overkill though. >>>> >>>> Sent from my iPhone >>>> >>>> On Mar 26, 2019, at 8:51, Vittorio Bertocci <vitto...@auth0.com> wrote: >>>> >>>> Hey Nov, Dominick, Hans- >>>> thanks for the comments. That was an area I was expecting to cause more >>>> discussion, and I am glad we are having this opportunity to clarify. >>>> The current language in the draft traces the etymology of sub to OpenID >>>> Connect core, hence Dominick observation is on point. However in the >>>> description I express something in line with 7519, which was in fact my >>>> intent. >>>> >>>> The idea was to provide an identifier of the calling subject that is >>>> guaranteed to be present in all cases- this would allow an SDK developer to >>>> use the same code for things like lookups and membership checks regardless >>>> of the nature of the caller (user in a delegated case, app in app-only >>>> grants). The information to discriminate between user and app callers is >>>> always available in the token (say, the caller is a user if sub!=client_id, >>>> where client_id is always guaranteed to be present as well) hence there's >>>> no loss in expressive power, should that difference be relevant for the >>>> resource server. >>>> >>>> Dominick, Hans- I probably missed the security issue you guys are >>>> thinking of in this case. Of course, if this would introduce a risk I >>>> completely agree it should be changed- I'd just like to understand better >>>> the problem. Could you expand it in a scenario/use case to clarify the >>>> risk? >>>> Nov- playing this back: is the concern that a user and a client might >>>> have the same identifier within an IDP? When using collision resistant IDs, >>>> as it is usually the case, that seems to be a remote possibility- did you >>>> stumble in such scenario in production? >>>> >>>> Thanks >>>> V. >>>> >>>> >>>> On Mon, Mar 25, 2019 at 7:44 AM Hans Zandbelt < >>>> hans.zandb...@zmartzone.eu> wrote: >>>> >>>>> I believe there are plenty of OAuth 2.0 only use cases out there... >>>>> but nevertheless I agree with the potential confusion and thus security >>>>> problems arising from that (though one may argue the semantics are the >>>>> same). >>>>> >>>>> Hans. >>>>> >>>>> On Mon, Mar 25, 2019 at 3:39 PM Dominick Baier < >>>>> dba...@leastprivilege.com> wrote: >>>>> >>>>>> Yes I know - and I think in hindsight it was a mistake to use the >>>>>> same claim type for multiple semantics. >>>>>> >>>>>> All the “this is OIDC not OAuth” arguments are making things more >>>>>> complicated than they need to be - in my experience almost no-one (that I >>>>>> know) does OIDC only - nor OAuth only. They always combine it. >>>>>> >>>>>> In reality this leads to potential security problems - this spec has >>>>>> the potential to rectify the situation. >>>>>> >>>>>> Dominick >>>>>> >>>>>> On 25. March 2019 at 14:58:56, Hans Zandbelt ( >>>>>> hans.zandb...@zmartzone.eu) wrote: >>>>>> >>>>>> Without agreeing or disagreeing: OIDC does not apply here since it is >>>>>> not OAuth and an access token is not an id_token. >>>>>> The JWT spec says in >>>>>> https://tools.ietf.org/html/rfc7519#section-4.1.2: >>>>>> >>>>>> "The "sub" (subject) claim identifies the principal that is the >>>>>> subject of the JWT. The claims in a JWT are normally statements >>>>>> about the subject. The subject value MUST either be scoped to be >>>>>> locally unique in the context of the issuer or be globally unique.. >>>>>> The processing of this claim is generally application specific" >>>>>> >>>>>> which kind of spells "client" in case of the client credentials grant >>>>>> but I also do worry about Resource Servers thinking/acting only in terms >>>>>> of >>>>>> users >>>>>> >>>>>> Hans. >>>>>> >>>>>> On Mon, Mar 25, 2019 at 2:41 PM Dominick Baier < >>>>>> dba...@leastprivilege.com> wrote: >>>>>> >>>>>>> IMHO the sub claim should always refer to the user - and nothing >>>>>>> else. >>>>>>> >>>>>>> OIDC says: >>>>>>> >>>>>>> "Subject - Identifier for the End-User at the Issuer." >>>>>>> >>>>>>> client_id should be used to identify clients. >>>>>>> >>>>>>> cheers >>>>>>> Dominick >>>>>>> >>>>>>> On 25.. March 2019 at 05:13:03, Nov Matake (mat...@gmail.com) wrote: >>>>>>> >>>>>>> Hi Vittorio, >>>>>>> >>>>>>> Thanks for the good starting point of standardizing JWT-ized AT. >>>>>>> >>>>>>> One feedback. >>>>>>> The “sub” claim can include 2 types of identifier, end-user and >>>>>>> client, in this spec. >>>>>>> It requires those 2 types of identifiers to be unique each other in >>>>>>> the IdP context. >>>>>>> >>>>>>> I prefer omitting “sub” claim in 2-legged context, so that no such >>>>>>> constraint needed. >>>>>>> >>>>>>> thanks >>>>>>> >>>>>>> nov >>>>>>> >>>>>>> On Mar 25, 2019, at 8:29, Vittorio Bertocci < >>>>>>> vittorio.bertocci=40auth0....@dmarc.ietf.org> 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. >>>>>>> _______________________________________________ >>>>>>> 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 >>>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> hans.zandb...@zmartzone.eu >>>>>> ZmartZone IAM - www.zmartzone.eu >>>>>> >>>>>> >>>>> >>>>> -- >>>>> hans.zandb...@zmartzone.eu >>>>> ZmartZone IAM - www.zmartzone.eu >>>>> >>>> _______________________________________________ >>>> OAuth mailing list >>>> OAuth@ietf.org >>>> https://www.ietf.org/mailman/listinfo/oauth >>>> >>> >>> >>> -- >>> Vennlig hilsen >>> >>> Steinar Noem >>> Partner Udelt AS >>> Systemutvikler >>> >>> | stei...@udelt.no <stei...@udelt..no> | h...@udelt.no | +47 955 21 620 >>> | www.udelt.no | >>> >> _______________________________________________ >> OAuth mailing list >> OAuth@ietf.org >> https://www.ietf.org/mailman/listinfo/oauth >> > > > -- > Dave Tonge > CTO > [image: Moneyhub Enterprise] > <http://www.google.com/url?q=http%3A%2F%2Fmoneyhubenterprise.com%2F&sa=D&sntz=1&usg=AFQjCNGUnR5opJv5S1uZOVg8aISwPKAv3A> > Moneyhub Financial Technology, 5th Floor, 10 Temple Back, Bristol, BS1 6FL > t: +44 (0)117 280 5120 > > Moneyhub Enterprise is a trading style of Moneyhub Financial Technology > Limited which is authorised and regulated by the Financial Conduct > Authority ("FCA"). Moneyhub Financial Technology is entered on the > Financial Services Register (FRN 809360) at fca.org.uk/register. Moneyhub > Financial > Technology is registered in England & Wales, company registration number > 06909772 . > Moneyhub Financial Technology Limited 2018 © > > DISCLAIMER: This email (including any attachments) is subject to > copyright, and the information in it is confidential. Use of this email or > of any information in it other than by the addressee is unauthorised and > unlawful. Whilst reasonable efforts are made to ensure that any attachments > are virus-free, it is the recipient's sole responsibility to scan all > attachments for viruses. All calls and emails to and from this company may > be monitored and recorded for legitimate purposes relating to this > company's business. Any opinions expressed in this email (or in any > attachments) are those of the author and do not necessarily represent the > opinions of Moneyhub Financial Technology Limited or of any other group > company. >
_______________________________________________ OAuth mailing list OAuth@ietf.org https://www.ietf.org/mailman/listinfo/oauth
