Re: [OAUTH-WG] Httpdir telechat review of draft-ietf-oauth-step-up-authn-challenge-13

[Mark Nottingham <[e-mail]>]

Thanks -- that looks good.

Cheers,


> On 6 Apr 2023, at 5:31 am, Brian Campbell <[e-mail]> wrote:
> 
> And that PR is here https://github.com/oauth-wg/oauth-step-up-authn-challenge/pull/3/files 
> 
> On Wed, Apr 5, 2023 at 10:59 AM Brian Campbell <[e-mail]> wrote:
> Thank you for the review Mark. I've replied inline below with some context or explanation as best I can. And I'll put together a PR with corresponding changes/clarifications. 
> 
> On Tue, Apr 4, 2023 at 11:18 PM Mark Nottingham via Datatracker <[e-mail]> wrote:
> Reviewer: Mark Nottingham
> Review result: Not Ready
> 
> # HTTPDIR review of drat-ietf-oauth-step-up-authn-challenge-13
> 
> I am an assigned HTTP directorate reviewer for draft-ietf-masque-connect-ip.
> These comments were written primarily for the benefit of the ART Area
> Directors. Document editors and shepherd(s) should treat these comments just
> like they would treat comments from any other IETF contributors and resolve
> them along with any other Last Call comments that have been received. For more
> details on the HTTP Directorate, see
> https://datatracker.ietf.org/group/intdir/about/.
> 
> I've entered a 'not ready' position because of the first issue below; the
> remaining are relatively easy to address.
> 
> ## Comments
> 
> ### Global HTTP Authentication Parameters
> 
> This draft seems to modify the HTTP authentication mechanism globally,
> regardless of the scheme in use. For example:
> 
> "This specification introduces a new error code value for the error parameter
> of [RFC6750] or authentication schemes, such as [I-D.ietf-oauth-dpop], which
> use the error parameter"
> 
> [...]
> 
> "Furthermore, this specification defines additional WWW-Authenticate auth-param
> values to convey the authentication requirements back to the client."
> 
> [...]
> 
> "A client receiving an authorization error from the resource server carrying
> the error code insufficient_user_authentication SHOULD parse the
> WWW-Authenticate header for acr_values and max_age and use them, if present, in
> constructing an authorization request"
> 
> If that is the intent, you need to update RFC9110 (which is likely to be
> contentious); otherwise, you need to scope it in such a way that authentication
> schemes 'opt into' their use.
> 
> The intent is definitely not to globally modify the HTTP authentication mechanism. Rather the intent is to provide a new error code and two new parameters for the "Bearer" authentication scheme challenge from RFC6750 (and other OAuth schemes like "DPoP" that use the RFC6750 challenge params).
> 
> 
>   
> ### Header Definition
> 
> "This document also introduces acr_values and max_age parameters for the
> WWW-Authenticate response header defined by [RFC6750]"
> 
> RFC6750 does not define WWW-Authenticate; RFC9110 does.
> 
> Yeah, that was sloppy language. Apologies. The parameters are introduced for the Bearer authentication scheme challenge defined by [RFC6750] not the WWW-Authenticate response header in general. 
>  
> 
> ## Nits
> 
> I found the terminology in this draft confused, and confusing. E.g.,
> 
> * Use of the term 'resource server' throughout is very jarring -- on the Web,
> it's just a 'resource'. The 'server' is responsible for the resource; if you
> mean the server, say 'server'; if you mean the resource, say 'resource'. Don't
> combine them.
> 
> * Likewise, 'resource request' is redundant; every request is for a resource.
> Just say 'request'.
> 
> * Similarly, the diagram on page 4 shows a 'resource server' returning a
> 'protected resource'. Resources are never transferred over the network; they
> send representations in responses -- one of those terms should be used.
> 
> As Aaron mentioned in his reply to this thread - these terms are defined in RFC6749 and used throughout the OAuth family of specs providing useful context and disambiguation for OAuth roles and functionality etc. I agree with Aaron about adding a terminology paragraph to the draft to make it more explicit. 
>   
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--
Mark Nottingham   https://www.mnot.net/