Re: [RFC] ext2 and ext3 block reservations can be bypassed

["Jakob Østergaard" <jakob@unthought.net>]

On Sun, May 12, 2002 at 06:23:21PM +0200, Kasper Dupont wrote:
> Usually the last 5% of the diskspace on ext2 and ext3
> filesystems are reserved for root. But I just realized
> that they can be bypassed by redirecting the output
> from a suid root program to a file.
> 
> This command will keep writing beyond the 95% limit:
> while true ; do mount ; done >filename

Hej Kasper,

Sure you were not running the shell as root ?  :)

The redirection is handled by your shell, mount doesn't have anything to do
with the '>filename' part.

Actually, the more fun test is to
  mount > /etc/passwd
or
  mount > /dev/hda

But this won't work either, unless your shell (and therefore you as a user,
suid programs or not) have the permissions as required.

In short: I don't think you are seeing what you think you are seeing  ;)

-- 
................................................................
:   jakob@unthought.net   : And I see the elder races,         :
:.........................: putrid forms of man                :
:   Jakob Østergaard      : See him rise and claim the earth,  :
:        OZ9ABN           : his downfall is at hand.           :
:.........................:............{Konkhra}...............: