Re: reiserfs one user DoS?

Mike Fedyk
2003-10-06T02:03:42Z

On Mon, Oct 06, 2003 at 01:51:49AM +0200, Erik Tews wrote:
> On Sun, Oct 05, 2003 at 06:09:24PM +0200, Christian Kujau wrote:
> > Hans Reiser schrieb:
> > >>I have found such strange thing:
> > >>
> > >>pseudo@avalon at 14:04:00 ~> dd if=/dev/zero of=file bs=1 count=0
> > >>seek=1000000000000
> > >>
> > >>After that my Intel Celeron 800 MHz/384M RAM 60G/Seagate U6 under
> > >>Linux-2.4.22-grsec on reiserfs was utilized 100% for more than 2 hours.
> > >>dd process can't be killed.
> > >>
> > >>Is this my flow or real bug?
> > >>
> > >it is fixed in reiser4. linux has a lot of DOS vulerabilities to logged
> > >in users, mostly due to the ability to consume all of some resource or
> > >another. forgive me for not discussing them publicly.;-)
> >
> > perhaps "ulimit" could help here.
>
> Really? If I got a process which is unkillable, how can the kernel kill
> this process if it runs out of cpu-time?

If it is unkillable, you're either talking about kernel bugs or NFS, and
root should be able to kill a user process that has run out of ulimit
resources.