Re: forkbombing Linux distributions

Natanael Copa
2005-03-23T14:45:25Z

On Wed, 2005-03-23 at 15:27 +0100, Max Kellermann wrote:
> On 2005/03/23 15:23, Natanael Copa <mlists@tanael.org> wrote:
> > On Wed, 2005-03-23 at 14:53 +0100, Max Kellermann wrote:
> > > The number of processes is counted per user, but CPU time and memory
> > > consumption is counted per process.
> >
> > So limiting maximum number of processes will automatically limit CPU
> > time and memory consumption per user?
>
> No. I was talking about RLIMIT_CPU and RLIMIT_DATA, compared to
> RLIMIT_NPROC. RLIMIT_NPROC limits the number of processes for that
> user, nothing else (slightly simplified explanation).

Yes, but if
RLIMIT_NPROC is per user and RLIMIT_CPU is per proc

the theoretical CPU limit per user is RLIMIT_NPROC * RLIMIT_CPU. So if
you half the RLIMIT_NPROC you will half the theoretical maximum CPU
limit per user.

Same with memory.

I don't know if that really solves anything, but a misbehaving process
(fork bomb) would need to consume the double RAM or CPU to do the same
"damage" if RLIMIT_NPROC is halved.

--
Natanael Copa