OK. I think we have as much consensus as we’re likely to get. I’ve updated the patch branch and PR to reflect this.
Yoav > On 22 Jan 2021, at 7:45, Martin Thomson <m...@lowentropy.net> wrote: > > On Fri, Jan 22, 2021, at 16:16, Yoav Nir wrote: >> See this PR: https://github.com/tlswg/tls-flags/pull/5 > > It looks like there is lots of disagreement there. I'm going to disagree > with others too. > >> All except the first are Server-side. > > Certificate is client-side too. > >> The controversy is about unsolicited flags. An unsolicited flag is a >> flag that is set in a Flags extension in a server-side message without >> having been first declared in the ClientHello extension. > > So I think that you need to separate requests from responses. Because > Certificate contains response to ClientHello or CertificateRequest, my view > is that CertificateRequest can contain any flag (provided that the definition > of that flag permits it or you don't know whether it does) and Certificate > can only contain flags that CertificateRequest did. > > This is part of what Ekr seems to have objected to, and I agree with him > there. A server should be able to use any flag in NewSessionTicket or > CertificateRequest because those are the messages that initiate an exchange > (NST doesn't generate any response, so it's an exchange with one flight, but > that's immaterial). > > To review: > ClientHello is answered by HelloRetryRequest, ServerHello, > EncryptedExtensions, and (server) Certificate. > CertificateRequest is answered by (client) Certificate. > NewSessionTicket is not answered (which is totally fine). > > Those three first messages above can include new flags. They can contain the > extension or not at the discretion of the entity that sends the message. > Those messages that are in response can only contain the extension if the > initiating message contained the extension. Furthermore, the extension can > only contain a specific flag if the initiating message contained that flag. > > In other words, each flag is treated just like an empty extension: you can > initiate an exchange with it, but you can only answer with it if it was > initiated with it. > > This differs a little from Chris who suggests that only NewSessionTicket can > include a flag that was previously not indicated. > > _______________________________________________ > TLS mailing list > TLS@ietf.org > https://www.ietf.org/mailman/listinfo/tls _______________________________________________ TLS mailing list TLS@ietf.org https://www.ietf.org/mailman/listinfo/tls
