Re: [OAUTH-WG] Adam Roach's No Objection on draft-ietf-oauth-mtls-16: (with COMMENT)

[Brian Campbell <[e-mail]>]

Regarding the comment on tls_client_auth_san_ip, some other reviewers have
suggested using the using the IPv6 Address Text Representation described in
RFC 5952 rather than the one from in RFC 4291. Which I think makes sense to
do. Maybe also with a note that the comparison of the addresses should done
using binary as suggested in https://tools.ietf.org/html/rfc5952#section-8

What do you think?

On Wed, Aug 21, 2019 at 4:07 PM Brian Campbell <[e-mail]>
wrote:

> Thanks Adam, I attempt to provide not-too-terrible replies to your
> comments inline below.
>
> On Mon, Aug 19, 2019 at 8:02 PM Adam Roach via Datatracker <
> [e-mail]> wrote:
>
>> ----------------------------------------------------------------------
>> COMMENT:
>> ----------------------------------------------------------------------
>>
>>
>> Thanks for the work that everyone did on this document. I have one
>> suggestion
>> for clarification, followed by a handful of editorial nits.
>>
>>
>> ---------------------------------------------------------------------------
>>
>> §2.1.2:
>>
>> >  tls_client_auth_san_ip
>> >     A string representation of an IP address in either dotted decimal
>> >     notation (for IPv4) or colon-delimited hexadecimal (for IPv6, as
>> >     defined in [RFC4291] section 2.2) that is expected to be present
>> >     as an iPAddress SAN entry in the certificate, which the OAuth
>> >     client will use in mutual TLS authentication.
>>
>> This probably needs some text that clarifies expectations around
>> comparison
>> and/or normalization. For example, if the iPAddress value in the cert is
>> "20 01 0d b8 00 00 00 00 00 00 00 00 c0 00 02 ca" (and a mask of all
>> F's), one
>> should presume that this would match both tls_client_auth_san_ip values
>> "2001:db8:0:0:0:0:c000:2ca" and "2001:DB8::192.0.2.202", right? If no,
>> then
>> this document needs to talk about normalization of address representation.
>>
>
> Can you help me with some text here? I'm a bit out of my realm, to be
> honest. I naively just want it to say that the tls_client_auth_san_ip value
> and iPAddress value in the cert need to be the same IP address. But I do
> realize "same" isn't totally clear as your comment and others have pointed
> out. But I don't know enough to know how to write it in a way that's
> suitable for this kind of thing.
>
> Alternatively, as I mentioned in my response to Ben (down a ways in
> https://mailarchive.ietf.org/arch/msg/oauth/TMaNYXJgZ3-kz4GNsIL4O-9ncgQ),
> I've never personally been able to think of a situation where
> tls_client_auth_san_ip is actually needed.  So maybe removing it all
> together is an option as well?
>
>
>
>>
>> ---------------------------------------------------------------------------
>>
>> §1:
>>
>> >  Layering on the abstract flow above, this document standardizes
>> >  enhanced security options for OAuth 2.0 utilizing client certificate
>> >  based mutual TLS.
>>
>> Nit: "client-certificate-based"
>>
>
> Mr. Kaduk beat you to this one. Will fix.
>
>
> >  OAuth 2.0 defines a shared secret method of client authentication but
>>
>> Nit: "shared-secret"
>>
>
> Will fix.
>
>
>>
>>
>> ---------------------------------------------------------------------------
>> §1:
>>
>> >  This document describes an additional
>> >  mechanism of client authentication utilizing mutual TLS certificate-
>> >  based authentication
>>
>> Nit: "mutual-TLS"
>>
>> >  Mutual TLS certificate-bound access tokens ensure that only the party
>>
>> Nit: "Mutual-TLS"
>>
>> >  Mutual TLS certificate-bound access tokens and mutual TLS client
>>
>> Nit: "Mutual-TLS... mutual-TLS"
>>
>> >  Additional client metadata parameters are introduced by this document
>> >  in support of certificate-bound access tokens and mutual TLS client
>> >  authentication.
>>
>> Nit: "mutual-TLS"
>>
>> The remainder of the document has several other uses of the phrase "mutual
>> TLS" as an adjective; they should be similarly hyphenated. I will not call
>> them out individually. (Non-adjectival uses should not contain hyphens, so
>> this isn't a simple find-and-replace operation.)
>>
>
> Understood. In theory anyway.  I'll take a pass thought the whole document
> and endeavor to find and hyphenate all the places that "mutual TLS" is used
> as an adjective.
>
>
>
>>
>>
>> ---------------------------------------------------------------------------
>>
>> §5:
>>
>> >  Authorization servers supporting both clients using mutual TLS and
>> >  conventional clients MAY chose to isolate the server side mutual TLS
>> >  behaviour to only clients intending to do mutual TLS, thus avoiding
>>
>> Nit: "behavior" (or adjust other spellings in the document to be
>> consistently
>> British).
>>
>
>  Ugh. I'm surprised my jingoistic spellcheck didn't flag that one. Will
> fix.
>

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