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Date: Thu, 30 Jun 2011 14:18:16 +0400
From: Vasiliy Kulikov <segoon@...nwall.com>
To: Eugene Teo <eugene@...hat.com>
Cc: oss-security@...ts.openwall.com
Subject: Re: CVE request: kernel: taskstats local DoS

On Wed, Jun 22, 2011 at 15:23 +0800, Eugene Teo wrote:
> On 06/22/2011 03:17 PM, Vasiliy Kulikov wrote:
> > "Currently a single process may register exit handlers unlimited times.
> > It may lead to a bloated listeners chain and very slow process terminations.
> > E.g. after 10KK sent TASKSTATS_CMD_ATTR_REGISTER_CPUMASKs ~300 Mb of
> > kernel memory is stolen for the handlers chain and "time id" shows 2-7
> > seconds instead of normal 0.003.  It makes it possible to exhaust all
> > kernel memory and to eat much of CPU time by triggerring numerous exits
> > on a single CPU.
> > 
> > The patch limits the number of times a single process may register
> > itself on a single CPU to one."
> > 
> > It makes it possible for unprivileged user eat kernel memory and CPU
> > without triggering OOM killer.
> > 
> > Was introduced in f9fd8914c1acca0d98b69d831b128d5b52f03c51.
> > 
> > http://lists.openwall.net/linux-kernel/2011/06/16/605
> 
> Please use CVE-2011-2484.

The fix:

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=26c4caea9d697043cc5a458b96411b86d7f6babd


Thanks,

-- 
Vasiliy Kulikov
http://www.openwall.com - bringing security into open computing environments

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