/usr/kde/3/share/config/kdm/Xreset (from kde 3.0.5a, in case you don't have any kde 3.0.x anymore)

Xreset (text/plain), 281 bytes, created by Daniel Mettler on 2003-01-09 22:19:26 UTC

#! /bin/sh
# Xreset - run as root after session exits

# Reassign ownership of the console to root, this should disallow
# assignment of console output to any random users's xterm. See Xstartup.
#
#chown root /dev/console
#chmod 622 /dev/console

exec sessreg -d -l $DISPLAY $USER