Re: Possible flaw in XFree?

From: Vanja Hrustic (
Date: 06/28/02

Date: Fri, 28 Jun 2002 23:24:45 +0700
From: Vanja Hrustic <>
To: "William N. Zanatta" <>

On Thu, 27 Jun 2002 16:06:55 -0300
"William N. Zanatta" <> wrote:

> Hi folks,
> Talking about some bad experiences with my friend, I discovered (he
> told me) it is possible to abort a X session even when the screen is
> locked by some kind of application like 'xlock'.
> I have made the following test:
> 1. Logged into the system as 'william' (a normal non-privileged
> user). 2. startx
> 3. Run xlock
> ... the screen is now locked...
> 4. Tried a hit on some keys. The password screen appears.
> 5. Then, 'ctrl-alt-backspace' and voila... X is down and my console
> is there, opened for me.

This is very old issue.

You don't even need to kill the X session. Just use CTRL+ALT+F[1-6] (at
least on Linux) to switch back to the console. If you get back to the
console from which X was started, just kill it with CTRL+C.

Never start X from your shell with 'startx' only. Use XDM/KDM/GSM or some
other display manager.

If you have to use startx, do something like:

"startx & exit"

Now, if X is killed with CTRL+ALT+BACKSPACE (or user switched back to
console) , it'll welcome you with the login prompt.


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 tunnel, go out and buy more tunnel. - John Quinton