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

[Bodo Moeller <[e-mail]>]

On Nov 15, 2009, at 12:38 PM, Marsh Ray wrote:

> Bodo Moeller wrote:
>>
>> How would they do that?  Everything is supposed to be encrypted then.
>
> They will notice handshake messages after the initial handshake. The
> record content type field is never encrypted.

Oh, so you meant *potentially* unsafe renegotiations.

>
>> I don't think the protocol should too much be designed around making
>> monitoring systems happy.  You can't do this for all interesting  
>> issues
>> that client or server implementations might have anyway.  Here we  
>> have a
>> vulnerability that's easy to fix in such a way that monitoring  
>> systems
>> can see some fix deployment information, so why not.  Adding extra  
>> flags
>> just for monitoring's sake, I'm not so sure.
>
> Many, many sites will configure their stateful firewalls to shoot down
> any potentially-unsafe renegotiations. Without plaintext indicators,
> that will mean all renegotiations.

Not sending the extension when you don't intend to abort if the server  
doesn't echo it back and don't intend to renegotiate seems right then.

Bodo