Re: [TLS] supported_versions question

2016-11-15 Thread Hubert Kario
On Monday, 31 October 2016 20:19:15 CET Dave Garrett wrote: > On Monday, October 31, 2016 08:05:59 pm Matt Caswell wrote: > > On 31/10/16 23:53, Dave Garrett wrote: > > >> I came up with some alternative wording that I think captures the > > >> discussion: > > >> > > >> https://github.com/tlswg/tl

Re: [TLS] supported_versions question

2016-11-07 Thread Brian Smith
Kurt Roeckx wrote: > So I guess you're also saying that a server that implements TLS > 1.1 to TLS 1.3, but disables TLS 1.2 and TLS 1.3 support should > ignore the supported_versions even when it knows about it? > > I guess I have same questions but with only TLS 1.3 disabled, to > be sure when w

Re: [TLS] supported_versions question

2016-10-31 Thread Dave Garrett
On Monday, October 31, 2016 08:05:59 pm Matt Caswell wrote: > On 31/10/16 23:53, Dave Garrett wrote: > >> I came up with some alternative wording that I think captures the > >> discussion: > >> > >> https://github.com/tlswg/tls13-spec/pull/748 > > > > I see no reason to require servers to validate

Re: [TLS] supported_versions question

2016-10-31 Thread Matt Caswell
On 31/10/16 23:53, Dave Garrett wrote: >> I came up with some alternative wording that I think captures the discussion: >> >> https://github.com/tlswg/tls13-spec/pull/748 > > I see no reason to require servers to validate the legacy version value. > That's just excess complexity. If the extension

Re: [TLS] supported_versions question

2016-10-31 Thread Dave Garrett
On Monday, October 31, 2016 07:26:30 pm Matt Caswell wrote: > On 31 October 2016 at 23:13, David Benjamin wrote: > > On Mon, Oct 31, 2016 at 6:34 PM Kurt Roeckx wrote: > >> > >> On Mon, Oct 31, 2016 at 07:11:10PM +, David Benjamin wrote: > >> > On Mon, Oct 31, 2016 at 2:57 PM Ilari Liusvaara

Re: [TLS] supported_versions question

2016-10-31 Thread Matt Caswell
On 31 October 2016 at 23:35, Eric Rescorla wrote: > Our current implementation also processes the extension unconditionally. > > I'm not convinced that this represents an improvement, both for the reason > that Kurt > indicates and just in terms of simplicity of story. The current design is > simp

Re: [TLS] supported_versions question

2016-10-31 Thread Eric Rescorla
Our current implementation also processes the extension unconditionally. I'm not convinced that this represents an improvement, both for the reason that Kurt indicates and just in terms of simplicity of story. The current design is simply "if supported_versions is present, then use it", whereas tr

Re: [TLS] supported_versions question

2016-10-31 Thread Matt Caswell
On 31 October 2016 at 23:13, David Benjamin wrote: > On Mon, Oct 31, 2016 at 6:34 PM Kurt Roeckx wrote: >> >> On Mon, Oct 31, 2016 at 07:11:10PM +, David Benjamin wrote: >> > On Mon, Oct 31, 2016 at 2:57 PM Ilari Liusvaara >> > >> > wrote: >> > >> > > On Mon, Oct 31, 2016 at 06:43:52PM +

Re: [TLS] supported_versions question

2016-10-31 Thread David Benjamin
On Mon, Oct 31, 2016 at 6:34 PM Kurt Roeckx wrote: On Mon, Oct 31, 2016 at 07:11:10PM +, David Benjamin wrote: > On Mon, Oct 31, 2016 at 2:57 PM Ilari Liusvaara > wrote: > > > On Mon, Oct 31, 2016 at 06:43:52PM +, Matt Caswell wrote: > > > A few supported_versions questions: > > > > > >

Re: [TLS] supported_versions question

2016-10-31 Thread Kurt Roeckx
On Mon, Oct 31, 2016 at 07:11:10PM +, David Benjamin wrote: > On Mon, Oct 31, 2016 at 2:57 PM Ilari Liusvaara > wrote: > > > On Mon, Oct 31, 2016 at 06:43:52PM +, Matt Caswell wrote: > > > A few supported_versions questions: > > > > > > 1) What should a server do if supported_versions is

Re: [TLS] supported_versions question

2016-10-31 Thread Kurt Roeckx
On Mon, Oct 31, 2016 at 09:30:10PM +0200, Ilari Liusvaara wrote: > On Mon, Oct 31, 2016 at 07:11:10PM +, David Benjamin wrote: > > > > We could say the versions extension only applies to 1.2 and up. I.e. don't > > bother advertising 1.1 and 1.0 as a client and servers ignore 1.1 and 1.0 > > wh

Re: [TLS] supported_versions question

2016-10-31 Thread Brian Smith
David Benjamin wrote: > Ilari Liusvaara wrote: > >> The case where legacy_version < TLS1.2 IIRC isn't specified, but >> ignoring legacy_version is reasonable in this case too. >> > I imagine that there will be three common implementations for the case where legacy_version < 1.2 and supported_ver

Re: [TLS] supported_versions question

2016-10-31 Thread Xiaoyin Liu
I think for question 1, it should ignore legacy_version, and select a version from supported_versions, because if a client only supports TLS 1.1 and TLS 1.3, in order to connect to pre-TLS1.3 server, it has to set legacy_version to TLS 1.1. I have no idea about questions 2 or 3. Best, Xia

Re: [TLS] supported_versions question

2016-10-31 Thread Ilari Liusvaara
On Mon, Oct 31, 2016 at 07:11:10PM +, David Benjamin wrote: > > We could say the versions extension only applies to 1.2 and up. I.e. don't > bother advertising 1.1 and 1.0 as a client and servers ignore 1.1 and 1.0 > when they see them in the version list. That keeps the protocol deployable >

Re: [TLS] supported_versions question

2016-10-31 Thread Ilari Liusvaara
On Mon, Oct 31, 2016 at 06:43:52PM +, Matt Caswell wrote: > A few supported_versions questions: > > 1) What should a server do if supported_versions is received but > ClientHello.legacy_version != TLS1.2? Fail the handshake, or just > ignore legacy_version? If legacy_version > TLS1.2, the spe