Re: [TLS] Publication has been requested for draft-ietf-tls-oldversions-deprecate-05

[Eric Rescorla <[e-mail]>]

On Sun, Oct 6, 2019 at 9:42 AM Benjamin Kaduk <[e-mail]> wrote:

> On Fri, Oct 04, 2019 at 09:57:53PM +0700, Rob Sayre wrote:
> > On Fri, Oct 4, 2019 at 9:48 PM Eric Rescorla <[e-mail]> wrote:
> >
> > >
> > >
> > > On Fri, Oct 4, 2019 at 7:43 AM Rob Sayre <[e-mail]> wrote:
> > >
> > >> On Fri, Oct 4, 2019 at 9:08 PM Cullen Jennings <[e-mail]> wrote:
> > >>
> > >>>
> > >>> I do not think you have consensus for that change to WebRTC - it was
> > >>> discussed extensively. ...
> > >>>
> > >>
> > >>  While that may be true, readers of this list might want to read a
> > >> rationale, rather than just the results of a negotiation. Is there a
> > >> rationale somewhere?
> > >>
> > >> It seems strange to put DTLS 1.0 (based on TLS 1.1) into new
> documents.
> > >>
> > >
> > > A few points.
> > >
> > > 1. It doesn't pull it in. There's no reference and there's just an
> > > informative statement.
> > >
> >
> > Shouldn't there be an informative reference?
>
> I think that's largely a question for the sponsoring AD (CC'd) and the RFC
> Editor.
>
> >
> > > 2. There is a rationale. In fact, the relevant text pretty much is all
> > > rationale.
> > >
> > >    All Implementations MUST support DTLS 1.2 with the
> > >    TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 cipher suite and the P-256
> > >    curve [FIPS186 <
> https://tools.ietf.org/html/draft-ietf-rtcweb-security-arch-20#ref-FIPS186>].
> Earlier drafts of this specification required DTLS
> > >    1.0 with the cipher suite TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, and
> > >    at the time of this writing some implementations do not support DTLS
> > >    1.2; endpoints which support only DTLS 1.2 might encounter
> > >    interoperability issues.
> > >
> > >
> > Yes, I read this section and I was wondering what the rationale was for
> the
> > text: "endpoints which support only DTLS 1.2 might encounter
> > interoperability issues." Is there some data behind this? I'm not
> > suggesting a change in the draft without more information, but I do
> wonder
> > how the WG came to agree on this text.
>
> My assumption (I was not following the work) is that it was a well-known
> fact among implementors at the time that some large implementations only
> implemented DTLS 1.0.


Yes, though I don't have data on it.


Accordingly, "might encounter interoperability
> issues" is a bland uncontroversial fact, in that context.  It's not clear
> to me that we are adding much value revisiting the rtcweb WG's decisions
> over here on the TLS WG without getting input from rtcweb about why they
> put it that way in the first place...
>

Fortunately, the WGs share a chair, so perhaps that chair could provide the
minutes, etc. :)

-Ekr


> -Ben
>