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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