[Mageia-dev] forkbomb protection
David W. Hodgins
davidwhodgins at gmail.com
Wed Nov 28 20:23:45 CET 2012
On Wed, 28 Nov 2012 13:00:05 -0500, Johnny A. Solbu <cooker at solbu.net> wrote:
> On Wednesday 28. November 2012 17.53, David Walser wrote:
>> Their pam package has a /etc/security/limits.d/90-nproc.conf file that has:
>> * soft nproc 1024
>> As the last comment on the bug says, it's a bit confusing that it's in limits.d/ and not the limits.conf file itself,
> His point is that any limits set in «/etc/security/limits.d/» overrides the «limits.conf» file.
>> and in fact I'm not sure what is responsible for processing limits.d/* as limits.conf says nothing about it (Fedora's is the exact same as ours).
> We should add some comments in «/etc/security/limits.conf» about it.
>> Anyway, one way or another it would be nice to have this limit set by default on Mageia, IMHO. WDYT?
> I think we should have this.
This is also being discussed in the usenet newsgroup alt.os.linux.mageia.
I've confirmed the forkbomb will kill my Mageia 2 x86-64 system, with
the default value for nprocs of 127910. Interestingly, it doesn't kill
the system if I run the forkbomb right after rebooting, only if it's been
in use for a while. This is a quad core with 16GB of ram.
I've added a line to /etc/security/limits.conf on my system, with
* hard nproc 10000
The forkbomb no longer has impact, except for the need to kill all
of the user's bash processes.
# ps -A|wc -l
I think 10000 should be more than adequate, yet low enough to stop the
bomb from killing the system.
Regards, Dave Hodgins
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