Wireshark-dev: Re: [Wireshark-dev] SSL decryption breaks after retransmission
From: Stephen Fisher <[email protected]>
Date: Tue, 6 May 2008 15:41:39 -0600
On Tue, May 06, 2008 at 10:17:54PM +0200, Sake Blok wrote:

> Today I noticed that SSL decryption breaks when there is a tcp 
> retransmission.

We never run out of things to fix, do we? :)

> To solve this issue, I can think of several options:
> 
> - Make the TCP dissector not forward retransmitted segments to higher 
> layer protocols, just like the normal TCP stack will do on the 
> receiving host. This will have a major impact on the way retransmitted 
> frames are displayed. Then again, the fully dissected segment is 
> already available.

Something about this just doesn't feel right.

> - Have a "retransmitted_data" flag in the frame-data structure which 
> can be set by a dissector to warn the called dissector that the data 
> is is receiving is actually a copy of earlier received data so that it 
> can take proper action in dissecting it.

I like this idea.  The next protocol can then use it if necessary or 
ignore it.

> Since the flag only has meaning between the calling and the called 
> dissector, I'm not so happy with it's presence in the frame-data 
> structure.

The packet info struct is probably a better place for it based on what 
is already in epan/packet_info.h's declaration of packet_info.

> - Accept that retransmitted frames will break SSL decryption and let 
> the user delete the retransmitted frames themselves with editcap.

Too much work for the user :).


Steve