From: Solar Designer <solar@openwall.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Vasiliy Kulikov <segoon@openwall.com>,
kernel-hardening@lists.openwall.com,
Randy Dunlap <rdunlap@xenotime.net>,
"Eric W. Biederman" <ebiederm@xmission.com>,
"Serge E. Hallyn" <serge.hallyn@canonical.com>,
Daniel Lezcano <daniel.lezcano@free.fr>,
Oleg Nesterov <oleg@redhat.com>, Tejun Heo <tj@kernel.org>,
Ingo Molnar <mingo@elte.hu>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org
Subject: Re: [RFC] ipc: introduce shm_rmid_forced sysctl
Date: Sat, 2 Jul 2011 21:31:36 +0400 [thread overview]
Message-ID: <20110702173136.GF26232@openwall.com> (raw)
In-Reply-To: <20110629151436.9be479fb.akpm@linux-foundation.org>
On Wed, Jun 29, 2011 at 03:14:36PM -0700, Andrew Morton wrote:
> What a horrid patch. But given the POSIX (mis?)feature I don't see a
> better way, and the feature seems desirable. Sigh.
>
> What sort of users would want to turn this on, and why?
Originally, I introduced it into Linux 2.0.x-ow to allow for resource
limits to be enforced on shared servers, such as with shared web
hosting. A user is supposed to be limited by RLIMIT_AS * RLIMIT_NPROC.
(This is awfully inflexible, lacking a separate per-user memory limit,
but at least it's something.) However, with shared memory segments a
user could bypass that limit, because those segments don't have to be
tied to a process. So the patch changed that, requiring that any shm
segment be tied to a process, or be destroyed.
Alexander
next prev parent reply other threads:[~2011-07-02 17:31 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-22 15:25 [RFC] ipc: introduce shm_rmid_forced sysctl Vasiliy Kulikov
2011-06-22 16:03 ` Randy Dunlap
2011-06-29 22:14 ` Andrew Morton
2011-06-30 9:21 ` Vasiliy Kulikov
2011-06-30 13:08 ` Vasiliy Kulikov
2011-07-01 11:25 ` Ingo Molnar
2011-07-01 11:35 ` Vasiliy Kulikov
2011-07-01 12:04 ` Ingo Molnar
2011-07-01 14:18 ` Alan Cox
2011-07-03 19:38 ` Ingo Molnar
2011-07-03 21:25 ` Alan Cox
2011-07-02 16:50 ` Solar Designer
2011-07-02 17:31 ` Solar Designer [this message]
2011-07-04 15:08 ` Oleg Nesterov
2011-07-04 15:36 ` Vasiliy Kulikov
2011-07-04 15:44 ` Oleg Nesterov
2011-07-04 16:06 ` Vasiliy Kulikov
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