Re: Client-Cert Header draft

[Kazuho Oku <[e-mail]>]

+1 to what Mike said.

As a side note, per my understanding, the PROXY Protocol [1] supported by
some TLS terminators has the capability of forwarding client certificates.
I think using that would be generally preferable to using HTTP header
fields, because that entire protocol (and therefore existing deployment
requirements of that protocol) is based on the assumption that it would be
used only between a trusted TLS terminator and backend servers.

[1] https://www.haproxy.org/download/1.8/doc/proxy-protocol.txt

2020年4月18日(土) 4:23 Mike Bishop <[e-mail]>:

> Despite the distaste for client certificates from some quarters, they are
> still both used and useful.  I’m certainly interested in seeing this
> progress.
>
>
>
> In today’s situation, the intermediary checks that the cert matches the
> rules it has been given to authenticate clients, and only forwards the
> requests from valid clients.  Arguably, the origin is offloading less trust
> in this draft’s model – the intermediary is responsible for validating that
> the client possesses the claimed certificate, but might leave the origin to
> decide what scope of access the certificate actually grants.  That allows
> finer-grained access control, but also allows greater ability to send
> requests back to the origin.  It also opens the door for intermediaries
> which don’t support this header to accidentally forward requests containing
> it.  Requiring intermediaries to drop it doesn’t get you much, since only
> those intermediaries aware of the spec will comply by dropping the header.
> To help address these, I’d like to see this mix in something that the
> intermediary holds and the client doesn’t, such as an exporter from its TLS
> connection to the server.
>
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>
> But all that is refinement – the core concept here is beneficial, and I’d
> like to see more engagement here.
>
>
>
> *From:* Brian Campbell <[e-mail]>
> *Sent:* Wednesday, April 15, 2020 5:01 PM
> *To:* HTTP Working Group <[e-mail]>
> *Subject:* Client-Cert Header draft
>
>
>
> Hello HTTP Working Group,
>
>
>
> I've somewhat inadvertently found myself working on this draft
> https://datatracker.ietf.org/doc/draft-bdc-something-something-certificate/,
> which aspires to define a "Client-Cert" HTTP header field that allows a TLS
> terminating reverse proxy to convey information about the client
> certificate of a mutually-authenticated TLS connection to an origin server
> in a common and predictable manner.
>
>
>
> I presented the concept
> <https://datatracker.ietf.org/meeting/107/materials/slides-107-secdispatch-client-cert-http-header-00>
> at the recent virtual IETF 107 secdispatch meeting
> <https://datatracker.ietf.org/meeting/107/materials/minutes-107-secdispatch-00>
> and the outcome from that was basically that there seems to be some
> interest in pursuing the work and the suggestion that the conversation be
> taken to the HTTPbis WG (and also keep TLS WG involved - presumably if the
> work progresses). And that's what brings me here. I also hope to get a
> little bit of time at one of the upcoming virtual interims to
> present/discuss the draft.
>
>
>
> Thanks,
>
> Brian
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-- 
Kazuho Oku