Hi, I just came across openssl documentation around the scenario I am testing (patched client and upatched server). My confusion is clear...
So only question I have is: How to force the client to send empty RI extension instead of the cipher in first client hello.. Thanks, Kunal On Wed, Jan 5, 2011 at 11:00 PM, kunal patel <[email protected]> wrote: > Hi, > > I am using openssl 0.9.8q and I am seeing following behavior: > > client sends SSL3_CK_SCSV for indicating the support of secure > renegotiation > server on receiving this cipher sets send_connection_binding to true > server in response sends empty renegotiation extension > client parses the extension and sets send_connection_binding to true > Both server and client perform subsequent handshake securely > > According to RFC 5746 client can also send empty renegotiation extension > (just like server). I do see the code to do it but it is never invoked > (mainly because send_connection_binding is not set when > ssl_add_clienthello_tlsext is called) when sending the first client hello. > Openssl by default sends SCSV cipher to indicate support. Now my question > is: > > --- how to disable sending cipher suite and enable sending empty extension > in the first client hello ? > > > Secondly, the current approach seems to break secure inline renegotiation > in case of unpatched server and patched client. I did testing where my > server was 0.9.8g (with no extension support) and my client was 0.9.8q. In > this case > > client sends SCSV > server ignores that cipher suite. > Since extensions are not compiled server hello doesn't include any > extension in server hello > Since client doesn't receive any extensions it doesn't set the > send_connection_binding to true > > This results in legacy renegotiation (both client and server doesn't set > the flag to true). > > It seems to me that we need to set send_connection_binding to true before > sending client hello to suggest that we support secure inline re-negotiation > irrespective of what server supports... > > Can some one please comment on this. Did I mis-read the code ? > > Thanks, > Kunal > >
