Re: [TLS] assert TLSext in renego-ServerHello instead of disable

[Martin Rex <[e-mail]>]

Marsh Ray wrote:
> 
> Bodo Moeller wrote:
> >
> > Arguably I'd rather have monitoring tell me about clients that will
> > *tolerate* a handshake with a server that doesn't support the extension
> > (not so much about clients that don't support the extension at all).  In
> > that case, I wouldn't want these clients to send the extension on the
> > initial handshake.
> 
> Good point.
> 
> These systems will probably spot unsafe renegotiations happening.
> 
> It may be that we need two bits: 'endpoint patched' and 'endpoint
> configured secure'.

Do you really need more?

If you see the client's signal in the ClientHello that it is updated
and no signal for the new behaviour in the ServerHello, then you can
distinguish configured secure (Client closes network connection with
or without sending a fatal alert) from configured insecure (handshake
continues).

If your idea is about being able to "check" client's configuration on
_any_ TLS connection, that is not something that TLS is designed
(or supposed) to provide.

-Martin