Subject: Re: SSH X11 forwarding crashes clients.
To: Ben Harris <>
From: Lars-Johan Liman <>
List: current-users
Date: 12/08/2005 11:34:26
> It probably would.  As I understand it, all that ssh does is to ask the X
> server for an untrusted cookie when setting up X forwarding.  It's then the
> X server that gives the BadWindow error to the X client, in response to
> which the X client closes the X connection.  For ssh to detect this, it
> would have to parse all of the X protocol requests going past and detect
> when the X server returned an error that it wouldn't have returned if the
> cookie had been a trusted one.  It's possible it might even need to detect
> whether the X client was planning to close the connection as a result (since
> a clever client might be able to work around the problem).

Ah. I'm slowly picking it up.

I rest my case.

> Of course, my understanding could be incorrect -- the ssh manual page wasn't
> very clear last time I looked.

>> How about: "Untrusted X11 client terminated. See ssh -Y flag." in the
>> ssh client end? Yes I understand that there are problems with the fact
>> that the X application doesn't have a direct relationship with SSH,
>> but still - ssh terminates the X11 session,

> What makes you think this?

How about: "Too old knowledge about X11 (the new release X11R3 was
just out when I began the journey ... :-), and the the gut feeling
that such strange behaviour would be a straight forward consequence of
a typical Theo de Raadt opinion."?

:-) :-)

Thanks for enlightening me.