Re: [Ace] Requested review for IANA registration in draft-ietf-ace-oauth-params

[Brian Campbell <[e-mail]>]

Apologies, I forgot to reply-all at some earlier point and dropped the
mailing lists and other cc's off the thread. Added back now.

And also apologies because I think I need to recuse myself from the DE
responsibility on the JWT registry request here. I've spent more time than
I'd like to admit or really have to spare on it and am still struggling to
understand.

I appreciate you pointing out the authz-info endpoint in ACE but I still
don't follow how "rs_cnf" in an access token would really work in practice.
The client sends the token to the RS's authz-info endpoint on an insecure
connection or one that has the server auth with potentially different key
and the RS stores the access token for later use. Then on resource access
the RS looks up the access token (with respect to the cnf key in it) based
on the key the client used in establishing a new mutually authentication
connection to the RS. For the RS to choose a key for server it will use
during the handshake (and as far as I know the server key is the first in
the authn process of the handshake) based on the "rs_cnf" in the access
token, it needs to remember and associate that client and the access token
with something else (IP address?) that will be available during the
handshake. It doesn't fit together for me in a way that seems likely to
work or be interoperable but, like I said, I'm really struggling to
understand.

On Thu, Jan 16, 2020 at 12:54 AM Seitz Ludwig <[e-mail]>
wrote:

> Hi Brian,
>
>
>
> Comments inline.
>
>
>
> /Ludwig
>
>
>
> *From:* Brian Campbell <[e-mail]>
> *Sent:* den 13 januari 2020 21:22
> *To:* Seitz Ludwig <[e-mail]>
> *Subject:* Re: [Ace] Requested review for IANA registration in
> draft-ietf-ace-oauth-params
>
>
>
> Thanks for the response and updates Ludwig,
>
>
>
> Please bear with me while I try to wrap my head around some things.
>
>
>
> The JWT registration request for the "rs_cnf" claim points to Sec 3.3
> <https://tools.ietf.org/html/draft-ietf-ace-oauth-params-08#section-3.3>
> saying it is "a hint [in the access token] to the RS about which key it
> should use to authenticate towards the client".  But doesn't the client
> have to go through the DTLS/TLS handshake with the RS (which is presumably
> when it authenticates to the client) before it presents the access token?
> I'm not seeing how this would work as seems the RS won't see the hint until
> after it needs it.
>
>
>
>
>
> [LS] Not in the ACE flow. We use the access token to establish keys at the
> RS both for the client and the RS. We have therefore defined a new
> ACE-OAuth endpoint (authz-info) at the RS. The client can POST access
> tokens to this endpoint without prior authentication.
>
> At that point, the RS only validates the signature/MAC by the AS.
>
>
>
> Later at the time of access, the corresponding token is linked to the
> access request via the pop-mechanism and the client/access specific parts
> are validated (e.g. scope, subject).
>
>
>
> Hope that clarifies things a bit.
>
>
>
> On Sat, Jan 11, 2020 at 8:30 AM Seitz Ludwig <[e-mail]>
> wrote:
>
> Hello again Brian,
>
>
>
> Thank you for reviewing this! Indeed the handling of JWT/JSON interactions
> was handled sloppily here. I will soon issue a draft update that specifies
> that the JSON-based interactions should use the syntax from RFC7800 while
> the CBOR-based ones should use ID.ietf-ace-cwt-proof-of-possession.
>
>
>
> This correction goes for all the use of “cnf”, “req_cnf” and “rs_cnf”.
>
>
>
> Regards,
>
>
>
> Ludwig
>
>
>
> *From:* Ace <[e-mail]> *On Behalf Of *Brian Campbell
> *Sent:* den 10 januari 2020 22:12
> *To:* Ludwig Seitz <[e-mail]>
> *Cc:* Roman Danyliw <[e-mail]>; [e-mail]; Jim Schaad <
> [e-mail]>; The IESG <[e-mail]>; [e-mail];
> [e-mail]; Benjamin Kaduk <[e-mail]>
> *Subject:* Re: [Ace] Requested review for IANA registration in
> draft-ietf-ace-oauth-params
>
>
>
> That  "rs_cnf" claim registration request in 9.1 points to 3.3 which says
> it has 'the same syntax and semantics as defined in for the "rs_cnf"
> parameter', which I think is in 4.1. And 4.1 says that the "rs_cnf" values
> 'follow the syntax of the "cnf" claim from section 3.1 of
> [I-D.ietf-ace-cwt-proof-of-possession].' Similar to other comments I've
> made today, I don't follow what that would mean for the value of the claim
> when it's a JWT. And that seems like something that's important to
> understand for the purpose of a JWT claims registry request.
>
>
>
>
>
> On Sat, Dec 21, 2019 at 4:11 AM Ludwig Seitz <[e-mail]> wrote:
>
> Hello JWT registry reviewers,
>
> the IESG-designated experts for the JWT claims registry have asked me to
> send a review request to you about the "rs_cnf" claim registered here:
>
> https://tools.ietf.org/html/draft-ietf-ace-oauth-params-07#section-9.1
>
> Thank you in advance for you review comments.
>
> Regards,
>
> Ludwig
>
> _______________________________________________
> Ace mailing list
> [e-mail]
> https://www.ietf.org/mailman/listinfo/ace
>
>
> *CONFIDENTIALITY NOTICE: This email may contain confidential and
> privileged material for the sole use of the intended recipient(s). Any
> review, use, distribution or disclosure by others is strictly prohibited..
> If you have received this communication in error, please notify the sender
> immediately by e-mail and delete the message and any file attachments from
> your computer. Thank you.*
>
>
> *CONFIDENTIALITY NOTICE: This email may contain confidential and
> privileged material for the sole use of the intended recipient(s). Any
> review, use, distribution or disclosure by others is strictly prohibited.
> If you have received this communication in error, please notify the sender
> immediately by e-mail and delete the message and any file attachments from
> your computer. Thank you.*
>

-- 
_CONFIDENTIALITY NOTICE: This email may contain confidential and privileged 
material for the sole use of the intended recipient(s). Any review, use, 
distribution or disclosure by others is strictly prohibited.  If you have 
received this communication in error, please notify the sender immediately 
by e-mail and delete the message and any file attachments from your 
computer. Thank you._