1. Changing GNOME System Menu
Change the gdm's config file
# vim /etc/X11/gdm/gdm.conf
Find a line in the gdm.conf
# SystemMenu = false
2. To Prevent users from opening a termina and running "poweroff" or "reboot"
Delete or move these files:
/etc/security/console.apps/poweroff
/etc/security/console.apps/reboot
3. Prevent shutdown using Alt-Ctrl-Del
# vim inittab
# Trap CTRL-ALT-DELETE
ca::ctrlaltdel:/sbin/shutdown -t3 -r now
And change it to read:
# Disallow CTRL-ALT-DELETE
ca::ctrlaltdel:/bin/echo "ctrl-alt-delete has been disabled"
Modify the ownership
#sudo chgrp root /sbin/halt /sbin/shutdown
#sudo chmod 550 /sbin/halt /sbin/shutdown
Articles:
- Disable Shutdown For Normal Users (Ubuntu Blog)
- Disable shutdown/reboot in GNOME logout menu (Fedora Mailing List)