Preventing users from shuting down the system

[hinsen dirac cnrs-orleans fr]

With a recent update to RedHat Linux 6.1, I also installed GNOME
and I am generally very pleased with it. However, there is one
severe security problem that would force me to uninstall GNOME
if there is no way to solve it. With the GNOME display manager,
any user can shut down or reboot the system, supplying nothing but
his own password. This is even listed as a "feature" in the
(scarce) description of gdmlogin!  On a multiuser system, it should
be impossible to shut down the machine without supplying the
root password.

I couldn't find any documentation on this topic, so I scanned the
configuration files and found the commands that are executed for
halting and rebooting. Setting them to nothing at least prevents the
worst, but users can still try to do a shutdown and thereby terminate
X, and then they panic and come to my office for help.

I can't believe that there is no way to turn all this off (i.e. make
the menu entries and radio buttons for halt and reboot disappear),
but how???
-- 
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Konrad Hinsen                            | E-Mail: hinsen@cnrs-orleans.fr
Centre de Biophysique Moleculaire (CNRS) | Tel.: +33-2.38.25.55.69
Rue Charles Sadron                       | Fax:  +33-2.38.63.15.17
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