X privileges

[towsonu2003]

Correct me if any of these assumptions are wrong here..

We run X with root privileges, right? as in
$ sudo /etc/init.d/gdm start

but we can also run X with user privileges by shutting down gdm and starting X with
$ startx
from a tty

Gnome launched like this will not even give you permission to shut down or restart the pc -only to log off. Gnome launched with sudo /etc/init.d/gdm start lets you shutdown or restart, hinting that it has more privileges that can be used.

am I right so far? if yes, my question is: are there risks associated with running X with root privileges?

PS. I'm not gonna say "let's change ubuntu". Just curious.

[LordHunter317]

Correct me if any of these assumptions are wrong here..

We run X with root privileges, right? as in
$ sudo /etc/init.d/gdm startNo, that runs the script /etc/init.d/gdm start. That doesn't mean any services it starts will stay as root, as they could drop privilege after startup (e.g., SSHD).


but we can also run X with user privileges by shutting down gdm and starting X with
$ startx
from a ttyNope. I think you'll find your X Server is setuid root and runs as root all the time.

Gnome launched like this will not even give you permission to shut down or restart the pc -only to log off.That's a design decision because it presumes it's not in total control.

Gnome launched with sudo /etc/init.d/gdm start lets you shutdown or restart, hinting that it has more privileges that can be used. GDM does sure, but I'm not sure what gnome-session does. At any rate, your actual applications don't run as root in either situation. X certainly does.

BTW, this can be trivally verified by do 'ps axu' on the console.

if yes, my question is: are there risks associated with running X with root privileges? There are plenty, but fixing it isn't easy without a large rewrite of xorg internals. OpenBSD has done some work in this area, but it's probably not portable to Linux without giving up some features.

[towsonu2003]

this was most informative, thanks :)