[PATCH xserver] check for elevated privileges not uid=0 (V2)

[Julien Cristau]

On Tue, Oct 11, 2011 at 02:00:27 +0700, Antoine Martin wrote:

> >+            /* XXX ouch, coudn't get back to original uid
> >+               what can we do ??? */
> >
> >If we get to this point, the code in the patch has failed. It should
> >apologize deeply and offer your phone number for technical support :)
> >Seriously, it should print an "internal error" message of some kind,
> >maybe including __function__. Just quitting silently and leave a
> >cryptic 127 that might or not propagate to the user does not cut it.
> Added a more helpful message. Notes:
> * most platforms I can get hold of now have "getresuid" or
> "issetugid", so this is unlikely to fire in the real world
> * when it does fire, the chances that setuid(0) does not fail but
> setuid(!=0) does is slim.
> 
> >
> >+            _exit(127);
> Changed to plain exit(127)
> 
> >Why do you use _exit() and not exit() here? This is not e.g. a forked
> >child that should escape normal clean-up?
> Are there are risks in calling the exit hooks as root? I can't see any.
> 
FatalError seems like the right thing to call here, not exit?

Cheers,
Julien