[OAUTH-WG] Adam Roach's Discuss on draft-ietf-oauth-discovery-08: (with DISCUSS and COMMENT)

[Adam Roach <[e-mail]>]

Adam Roach has entered the following ballot position for
draft-ietf-oauth-discovery-08: Discuss

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DISCUSS:
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Thanks to everyone who worked on this specification. I think it's well-written,
clear, and useful. I fully endorse publication, and intend to ballot "yes" once
we come to an agreement on the issue I describe below.

The problem I'm running into is the URL synthesis rules described in section
3.1 for multi-tenancy engage in exactly the kind of behavior that RFC 5785 was
designed to head off: it creates URLs all over the path space of the authority,
rather than coralling all synthesized URLs to live under only one top-level
directory. One of the key aspects of the principles of the web architecture is
URI opacity <https://www.w3.org/TR/webarch/#uri-opacity>, which generally
precludes clients from synthesizing URLs. RFC 5785 was intended as a very
limited carve-out to the principle of URI opacity, and was carefully limited to
a single top-level path element. This specification oversteps that carve-out by
exploding the location that "Well-Known" synthesized URLs can appear: it
literally increases it from one location (the root) to infinite locations (at
the end of any arbitrary path).

Fortunately, this defect is trivial to fix. Rather than placing .well-known
path components *after* the path identified by an issuer identifier, you place
them *before* it, which amends this document's usage to be within the spirit
intended by RFC 5785. For example, the example in section 3.1:

     GET /issuer1/.well-known/oauth-authorization-server HTTP/1.1
     Host: example.com

Would instead become:

     GET /.well-known/oauth-authorization-server/issuer1 HTTP/1.1
     Host: example.com


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COMMENT:
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Section 1.1: [this is an editorial suggestion that I leave to the editors'
discretion] This document makes use of uncapitalized "must", "should", and
"may" in places. Please consider using the RFC 8174 boilerplate instead of the
RFC 2119 boilerplate.

Section 7.2: [this is an important procedural comment that really should be
resolved prior to publication] The addition of restrictions to registries
established by RFC 6749 would seem to require that this document formally
include "Updates: RFC6749" in its metadata, as well as a mention of such an
update in its Abstract and Introduction sections.