From: Manfred Spraul <manfred@colorfullife.com>
Date: Tue, 29 Apr 2008 08:00:59 +0000 (-0700)
Subject: ipc: sysvsem: force unshare(CLONE_SYSVSEM) when CLONE_NEWIPC
X-Git-Tag: v2.6.26-rc1~531
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6013f67fc1a4c7fa5bcab2d39c1eaa3e260c7ac1;p=pandora-kernel.git

ipc: sysvsem: force unshare(CLONE_SYSVSEM) when CLONE_NEWIPC

sys_unshare(CLONE_NEWIPC) doesn't handle the undo lists properly, this can
cause a kernel memory corruption.  CLONE_NEWIPC must detach from the existing
undo lists.

Fix, part 2: perform an implicit CLONE_SYSVSEM in CLONE_NEWIPC.  CLONE_NEWIPC
creates a new IPC namespace, the task cannot access the existing semaphore
arrays after the unshare syscall.  Thus the task can/must detach from the
existing undo list entries, too.

This fixes the kernel corruption, because it makes it impossible that
undo records from two different namespaces are in sysvsem.undo_list.

Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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