Best way to kill a user's X11 session...

[Jeff Ross]

Hi all,

Wrapping up the cybercafe project, and what a journey it has been. The
whole trip into s/key passwords turned out to be a complete wrong turn,
but I've figured out a better, simpler, and I think just as secure,
alternative. Details forthcoming soon...

I'd like to be able to remotely kill a user's X11 session without
restarting the whole box. Partly I want to do this if a user logs in
but then forgets to log out when they go up to the counter to pay, and
partly for the option to kill a user's session if they are violating
Zen's "No pornography. No exceptions." internet usage policy. If
invoked, line via a cgi script using an ssh command, I want to kill the
current session, reset everything, including the password, and bring up
the Xlogin widgit for the next login.

The man page for xdm talks about an Xreset script that can be used to
reset the X server, and that sounds just perfect. Unfortunately, if
the Xreset script is on an OpenBSD box I can't find it.

I've tried sending a -HUP to xdm itself, but that didn't work, in fact,
I couldn't see a change at all, although I thought it should according
to the man page. Killing the user's specific XSession works the first
time it is invoked, but after that it locks the box up so hard you
can't switch virtual consoles back to the console, nor can you ssh in,
forcing a power switch reboot. Unacceptable.

Anybody got a pointer in the general vicinity of the right direction?

Reply to the list, please, for the archives, or use this address to
bypass TMDA
jross-dated-***@openvistas.net

Thanks!

Jeff
--
Jeff Ross
Open Vistas Networking, Inc.
http://www.openvistas.net

[Han Boetes]

~% cat killallX
#!/bin/sh

# Put the whole thing in () so it won't kill itself before finishing.
(
for i in $(xlsclients|awk '{print $2}'); do
kill $(pgrep ${i##*/})
done
kill $(pgrep fluxbox)
)&


# Han

[David S.]

Post by Jeff Ross
I'd like to be able to remotely kill a user's X11 session without
restarting the whole box. Partly I want to do this if a user logs in
but then forgets to log out when they go up to the counter to pay, and
partly for the option to kill a user's session if they are violating
Zen's "No pornography. No exceptions." internet usage policy. If
invoked, line via a cgi script using an ssh command, I want to kill the
current session, reset everything, including the password, and bring up
the Xlogin widgit for the next login.
Anybody got a pointer in the general vicinity of the right direction?

'ports/sysutils/skill':

skill <user name>

David S.

[Jeff Ross]

Post by Jeff Ross
Hi all,
Wrapping up the cybercafe project, and what a journey it has been.
The whole trip into s/key passwords turned out to be a complete wrong
turn, but I've figured out a better, simpler, and I think just as
secure, alternative. Details forthcoming soon...
I'd like to be able to remotely kill a user's X11 session without
restarting the whole box. Partly I want to do this if a user logs in
but then forgets to log out when they go up to the counter to pay, and
partly for the option to kill a user's session if they are violating
Zen's "No pornography. No exceptions." internet usage policy. If
invoked, line via a cgi script using an ssh command, I want to kill
the current session, reset everything, including the password, and
bring up the Xlogin widgit for the next login.
The man page for xdm talks about an Xreset script that can be used to
reset the X server, and that sounds just perfect. Unfortunately, if
the Xreset script is on an OpenBSD box I can't find it.
I've tried sending a -HUP to xdm itself, but that didn't work, in
fact, I couldn't see a change at all, although I thought it should
according to the man page. Killing the user's specific XSession works
the first time it is invoked, but after that it locks the box up so
hard you can't switch virtual consoles back to the console, nor can
you ssh in, forcing a power switch reboot. Unacceptable.
Anybody got a pointer in the general vicinity of the right direction?
Reply to the list, please, for the archives, or use this address to
bypass TMDA
Thanks!
Jeff
--
Jeff Ross
Open Vistas Networking, Inc.
http://www.openvistas.net

I got three different ways to accomplish this task. In a private
e-mail, I was reminded that killing the process that has the first
connection to the Xserver will force the X server itself to exit and
restart.

That turned out to be the easiest of the three to implement, thanks
largely to OpenBSD's security. That first process is apparently the
only process run by the unprivileged user _x11. This one-liner, then,
does the job quite nicely.

sudo kill `ps -aux | grep [_]x11 | cut -c 10-15`


Thanks again. All I have left to do now is add the wireless AP, and
how hard can that be with authpf? I hope those aren't "famous last
words" :-)

Jeff
--
Jeff Ross
Open Vistas Networking, Inc.
http://www.openvistas.net