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SubjectRe: [RFC] ext2 and ext3 block reservations can be bypassed
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}...............:
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