Re: [TLS] Renego Indication RI patch interaction with TLS major version interop

[Peter Gutmann <[e-mail]>]

"Brian Smith" <[e-mail]> writes:

>NSS has an explicit check that the first byte of every version number is
>0x03. I imagine other implementations have a similar check.

I do that too, and it's quite deliberate, we've been using 3.x for 15-odd
years and there's no sign, even with major incompatible protocol revisions,
that we're going to 4.x at any point.  Any change to 4.x is therefore going to
either never happen or will be something so major, probably a complete break
of the entire protocol, that I want to force users to upgrade to a completely
new release.

>His test would probably be much more successful if he used 0x03FF as the
>version number.

That's the other thing, if 4.x does ever appear then servers can use the SSH
2.x trick of advertising version 'next-version - 1' (in SSH it was 1.99, in
TLS it'd presumably be 3.255 or at least 3.99) to indicate a backwards and
forwards-compatible server.

Peter.