1. I see the value of client discovery for registered clients as well as for registering clients. For example, the client may be registered at a number of ASes, and a discovery document lets the client update its information once at its discovery endpoint rather than having to manually update the information at each AS. A key example of this (pun intended) is client key rotation. => I'd suggest updating the introduction to not be focussed on registration, but as a way for the AS to learn about a client.
2. I'm strongly opposed to JSON-LD as an optional format. Extra complexity for an AS to support with no added value since JSON is already being supported so would not be able to take advantage of any JSON-LD features. 3. I agree with using .well-known for discovery. It has become pretty common now, and that pattern helps prevent there being a conflict with any existing content / routes that are at the client endpoint. 4. This proposal presumes the client provides the same redirect_urs to each AS. In the clients that I have deployed, I have unique redirect URIs for each AS to assist in knowing which AS has sent back the redirect. For example, I append an AS specific slug to the redirect URI. How would that be handled in this proposal? One path would be for me to provide an AS specific URI for the client to each AS. 5. In HellÅ -- we offer developers the option to include a logo to be used for dark themed experiences in addition to the standard light themed experience. 6. I did not see URIs for the standard terms (ToS) of service and privacy policy (PP) URIs 7. on the ToS and PP topics, we could include version info so that it is easier for the AS to detect if the ToS and PP have been updated since the last time the user provided consent 8. I prefer the other proposal I saw where 'client_uri` was used to signal that client info was at a URI rather than using 'client_id', and client_id and client_uri would be mutually exclusive. Doing this for both the authorization and token endpoints would be what I would propose. Note that we are deprecating the redirect_uri to be in the token request in OAuth 2.1. 9. With client discovery, we can more easily move to the client authenticating with a signed request rather than a client secret, so a jwks_uri would be a great addition 10. The string comparison in section (6) is confusing. My understanding is that we have gone with byte comparisons with no transformations. What am I missing? /Dick 10. On Wed, Dec 14, 2022 at 5:14 AM Dmitry Telegin <dmitryt= 40backbase....@dmarc.ietf.org> wrote: > Hi Tobias, > > On Wed, Dec 14, 2022 at 2:49 AM Tobias Looker <tobias.looker= > 40mattr.glo...@dmarc.ietf.org> wrote: > >> >> There are certainly things we could explore here, one such option could >> be to continue to only return application/json but for the document to >> include an element like "@context" in the response if its desired that the >> metadata be processable as a JSON-LD document. >> > > I'd generally agree; my only concern about the Content-type is that it > could be set by the web server rather than the developer, and developers > might have no control over the web server configuration. If, for example, > the metadata is deployed as a static JSON-LD file, and the web server uses > MIME DB, then it will serve the resource as application/ld+json rather than > application/json (unless reconfigured to do so). > > >> >> Yes I've had similar thoughts about this, I think RFC 9111 could be a >> good basis. What remains a little unclear to me is what normative >> requirements we might impose on implementers in regards to caching, for >> instance I think requiring clients hosting their metadata to implement HTT >> request caching would be too strict, but if they are to implement it, RFC >> 9111 is recommended and if you do here is how it must be implemented? >> > > I agree that requiring clients to implement caching (i.e. to guarantee Age > and Cache-Control headers) might be excessively strict. But in the case > where the headers are not present, I think we should recommend the ASes to > implement some opinionated defaults (e.g., default TTL for client metadata > = 1 hour etc.) > > Dmitry > > >> >> Thanks, >> >> [image: Mattr website] >> <https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fscanmail.trustwave.com%2F%3Fc%3D15517%26d%3Dw46s4eMXULV_ns1ZfAKYLbVKcqey_PHiW1WeN4boYw%26u%3Dhttps%253a%252f%252fmattr.global%252f&data=04%7C01%7CSteve.Lowes%40mbie.govt.nz%7C5a65fe33c70b41fd8ba908d976f3a2f1%7C78b2bd11e42b47eab0112e04c3af5ec1%7C0%7C0%7C637671611076709977%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=tKqCMzLUQNCeORd908YqfqZoT7tCy%2FMVwXdjpch1sDY%3D&reserved=0> >> >> >> >> *Tobias Looker* >> >> MATTR >> CTO >> >> +64 (0) 27 378 0461 >> tobias.looker@mattr.global >> >> [image: Mattr website] >> <https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fscanmail.trustwave.com%2F%3Fc%3D15517%26d%3Dw46s4eMXULV_ns1ZfAKYLbVKcqey_PHiW1WeN4boYw%26u%3Dhttps%253a%252f%252fmattr.global%252f&data=04%7C01%7CSteve.Lowes%40mbie.govt.nz%7C5a65fe33c70b41fd8ba908d976f3a2f1%7C78b2bd11e42b47eab0112e04c3af5ec1%7C0%7C0%7C637671611076709977%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=tKqCMzLUQNCeORd908YqfqZoT7tCy%2FMVwXdjpch1sDY%3D&reserved=0> >> >> [image: Mattr on LinkedIn] >> <https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fscanmail.trustwave.com%2F%3Fc%3D15517%26d%3Dw46s4eMXULV_ns1ZfAKYLbVKcqey_PHiW1SbN9fvNg%26u%3Dhttps%253a%252f%252fwww.linkedin.com%252fcompany%252fmattrglobal&data=04%7C01%7CSteve.Lowes%40mbie.govt.nz%7C5a65fe33c70b41fd8ba908d976f3a2f1%7C78b2bd11e42b47eab0112e04c3af5ec1%7C0%7C0%7C637671611076719975%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=t%2BidOI32oaKuTJf1AkcG%2B%2FirIJwbrgzXVZnjOAC52Hs%3D&reserved=0> >> >> [image: Mattr on Twitter] >> <https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fscanmail.trustwave.com%2F%3Fc%3D15517%26d%3Dw46s4eMXULV_ns1ZfAKYLbVKcqey_PHiW1WdMte6ZA%26u%3Dhttps%253a%252f%252ftwitter.com%252fmattrglobal&data=04%7C01%7CSteve.Lowes%40mbie.govt.nz%7C5a65fe33c70b41fd8ba908d976f3a2f1%7C78b2bd11e42b47eab0112e04c3af5ec1%7C0%7C0%7C637671611076729970%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=BD9WWyXEjVGlbpbCja93yW%2FzLJZpe%2Ff8lGooe8V6i7w%3D&reserved=0> >> >> [image: Mattr on Github] >> <https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fscanmail.trustwave.com%2F%3Fc%3D15517%26d%3Dw46s4eMXULV_ns1ZfAKYLbVKcqey_PHiWwGdMoDtMw%26u%3Dhttps%253a%252f%252fgithub.com%252fmattrglobal&data=04%7C01%7CSteve.Lowes%40mbie.govt.nz%7C5a65fe33c70b41fd8ba908d976f3a2f1%7C78b2bd11e42b47eab0112e04c3af5ec1%7C0%7C0%7C637671611076729970%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=4AhRuXZCnU5i3hcngo4H3UiNayYUtXpRcImV4slS1mw%3D&reserved=0> >> >> >> This communication, including any attachments, is confidential. If you >> are not the intended recipient, you should not read it - please contact me >> immediately, destroy it, and do not copy or use any part of this >> communication or disclose anything about it. Thank you. Please note that >> this communication does not designate an information system for the >> purposes of the Electronic Transactions Act 2002. >> >> ------------------------------ >> *From:* Dmitry Telegin <dmitryt=40backbase....@dmarc.ietf.org> >> *Sent:* 14 December 2022 06:30 >> *To:* Tobias Looker <tobias.looker@mattr.global> >> *Cc:* Ben Schwartz <bem...@google.com>; oauth@ietf.org <oauth@ietf.org> >> *Subject:* Re: [OAUTH-WG] OAuth2 Client Discovery >> >> EXTERNAL EMAIL: This email originated outside of our organisation. Do not >> click links or open attachments unless you recognise the sender and know >> the content is safe. >> >> Hello Tobias, thanks for the draft! In regards to prior art, I'd like to >> mention Solid Project and their OIDC flavor, Solid-OIDC: >> https://solid.github.io/solid-oidc/#clientids-document >> >> They're using a similar approach (and have been for years), though with >> some differences: >> - client_id points to a URL that must resolve to the client metadata >> document directly (no .well-known/* used); >> - the document's format is JSON-LD, a superset of JSON. >> >> In order to maintain compatibility with Solid and similar existing >> technologies, would it make sense to mention that: >> - while retrieving client metadata, AS should recognize not only >> application/json, but application/ld+json (or maybe even >> application/*+json, as per >> https://datatracker.ietf.org/doc/html/rfc6839#section-3-1)? >> - any unknown fields (like JSON-LD "@context") must be ignored? >> >> On an unrelated note, it would be nice to cover the issue of caching the >> client metadata on the AS side. Obviously, we wouldn't want to re-request >> the metadata upon every request to the authorization endpoint. Would RFC >> 9111 suffice here? If so, which subset should be guaranteed to be supported >> by the AS? >> >> Thanks, >> Dmitry >> >> On Wed, Nov 9, 2022 at 8:36 PM Tobias Looker <tobias.looker= >> 40mattr.glo...@dmarc.ietf.org> wrote: >> >> Hi Ben, >> >> See below for some thoughts. >> >> > I'm having trouble understanding the precise URL structures that are >> used here. Can client_uri include a nontrivial path? Why is it necessary >> to repeat client_uri in the response JSON? >> >> The intent here is to follow how "OAuth 2.0 authorization metadata" works >> (RFC 8414) which requires the client resolving the authorization server >> metadata to check that the issuer in the resolved document matches the >> issuer URL they started the resolution with, see below for the relevant >> extract from RFC 8414. >> >> " >> >> The "issuer" value returned MUST be identical to the authorization >> server's issuer identifier value into which the well-known URI string >> was inserted to create the URL used to retrieve the metadata. If >> these values are not identical, the data contained in the response >> MUST NOT be used. >> >> >> " >> >> So the equivalent with our draft is to require the authorization server >> to validate that the client_uri returned in the clients metadata response >> matches the URL that was used to retrieve the metadata. >> >> > The use of .well-known is a bit unusual. Why not just host the JSON >> at the client_uri? >> >> Just to clarify it is, just under a well-known path? e.g if the client >> uri is https://client.example.com then the metadata would be published >> at https://client.example.com/.well-known/oauth-client >> >> > Finally, I note that the section on Impersonation Attacks doesn't >> mention the client_name or logo_uri. If these are to be shown to the user, >> they present a very serious impersonation risk that ought to be discussed. >> (The client_name also might need to be localized, which could be done by >> fetching the JSON document with an appropriate Accept-Language request >> header.) >> >> Yes absolutely agree this is an important security consideration to >> highlight, I will capture an issue. >> >> >> Thanks, >> >> [image: Mattr website] >> <https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fscanmail.trustwave.com%2F%3Fc%3D15517%26d%3Dw46s4eMXULV_ns1ZfAKYLbVKcqey_PHiW1WeN4boYw%26u%3Dhttps%253a%252f%252fmattr.global%252f&data=04%7C01%7CSteve.Lowes%40mbie.govt.nz%7C5a65fe33c70b41fd8ba908d976f3a2f1%7C78b2bd11e42b47eab0112e04c3af5ec1%7C0%7C0%7C637671611076709977%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=tKqCMzLUQNCeORd908YqfqZoT7tCy%2FMVwXdjpch1sDY%3D&reserved=0> >> >> >> >> *Tobias Looker* >> >> MATTR >> CTO >> >> +64 (0) 27 378 0461 >> tobias.looker@mattr.global >> >> [image: Mattr website] >> <https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fscanmail.trustwave.com%2F%3Fc%3D15517%26d%3Dw46s4eMXULV_ns1ZfAKYLbVKcqey_PHiW1WeN4boYw%26u%3Dhttps%253a%252f%252fmattr.global%252f&data=04%7C01%7CSteve.Lowes%40mbie.govt.nz%7C5a65fe33c70b41fd8ba908d976f3a2f1%7C78b2bd11e42b47eab0112e04c3af5ec1%7C0%7C0%7C637671611076709977%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=tKqCMzLUQNCeORd908YqfqZoT7tCy%2FMVwXdjpch1sDY%3D&reserved=0> >> >> [image: Mattr on LinkedIn] >> <https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fscanmail.trustwave.com%2F%3Fc%3D15517%26d%3Dw46s4eMXULV_ns1ZfAKYLbVKcqey_PHiW1SbN9fvNg%26u%3Dhttps%253a%252f%252fwww.linkedin.com%252fcompany%252fmattrglobal&data=04%7C01%7CSteve.Lowes%40mbie.govt.nz%7C5a65fe33c70b41fd8ba908d976f3a2f1%7C78b2bd11e42b47eab0112e04c3af5ec1%7C0%7C0%7C637671611076719975%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=t%2BidOI32oaKuTJf1AkcG%2B%2FirIJwbrgzXVZnjOAC52Hs%3D&reserved=0> >> >> [image: Mattr on Twitter] >> <https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fscanmail.trustwave.com%2F%3Fc%3D15517%26d%3Dw46s4eMXULV_ns1ZfAKYLbVKcqey_PHiW1WdMte6ZA%26u%3Dhttps%253a%252f%252ftwitter.com%252fmattrglobal&data=04%7C01%7CSteve.Lowes%40mbie.govt.nz%7C5a65fe33c70b41fd8ba908d976f3a2f1%7C78b2bd11e42b47eab0112e04c3af5ec1%7C0%7C0%7C637671611076729970%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=BD9WWyXEjVGlbpbCja93yW%2FzLJZpe%2Ff8lGooe8V6i7w%3D&reserved=0> >> >> [image: Mattr on Github] >> <https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fscanmail.trustwave.com%2F%3Fc%3D15517%26d%3Dw46s4eMXULV_ns1ZfAKYLbVKcqey_PHiWwGdMoDtMw%26u%3Dhttps%253a%252f%252fgithub.com%252fmattrglobal&data=04%7C01%7CSteve.Lowes%40mbie.govt.nz%7C5a65fe33c70b41fd8ba908d976f3a2f1%7C78b2bd11e42b47eab0112e04c3af5ec1%7C0%7C0%7C637671611076729970%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=4AhRuXZCnU5i3hcngo4H3UiNayYUtXpRcImV4slS1mw%3D&reserved=0> >> >> >> This communication, including any attachments, is confidential. If you >> are not the intended recipient, you should not read it - please contact me >> immediately, destroy it, and do not copy or use any part of this >> communication or disclose anything about it. Thank you. Please note that >> this communication does not designate an information system for the >> purposes of the Electronic Transactions Act 2002. >> >> ------------------------------ >> *From:* Ben Schwartz <bemasc=40google....@dmarc.ietf.org> >> *Sent:* 10 November 2022 07:04 >> *To:* Tobias Looker <tobias.looker@mattr.global> >> *Cc:* oauth@ietf.org <oauth@ietf.org> >> *Subject:* Re: [OAUTH-WG] OAuth2 Client Discovery >> >> EXTERNAL EMAIL: This email originated outside of our organisation. Do not >> click links or open attachments unless you recognise the sender and know >> the content is safe. >> >> _______________________________________________ >> 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 >
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