[TLS] Need for S->C signaling

[Stefan Santesson <stefan at aaa-sec.com>]

Title: Need for S->C signaling

Just a question to make sure we have accurately exhausted this aspect.

Is it really necessary for the Server to signal that is is patched other than using a modified finished calculation if it is patched/upgraded.

One scenario could be:

1) Client use the magic cipher suite to signal that it is patched/upgraded.
2) Client sends a normal finished message.
3a) Un-patched server replies with normal finished message.
3b) Patched server replies with upgraded finished message.

This way the client could determine whether the server is patched or not and act accordingly and get the security context of renegotiate from the patched server.

There are probably reasons why this is not a good idea. I’m just not really sure what they are.

/Stefan