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| author | Manfred Spraul <manfred@colorfullife.com> | 2008-04-29 01:00:59 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-29 08:06:14 -0700 |
| commit | 6013f67fc1a4c7fa5bcab2d39c1eaa3e260c7ac1 (patch) | |
| tree | 33f61a88048e659359864ec10104e304d8a97a73 /kernel/fork.c | |
| parent | 9edff4ab1f8d82675277a04e359d0ed8bf14a7b7 (diff) | |
| download | linux-6013f67fc1a4c7fa5bcab2d39c1eaa3e260c7ac1.tar.bz2 | |
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>
Diffstat (limited to 'kernel/fork.c')
| -rw-r--r-- | kernel/fork.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index 01666979beac..de5c16c6b6ec 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1696,7 +1696,12 @@ asmlinkage long sys_unshare(unsigned long unshare_flags) CLONE_NEWNET)) goto bad_unshare_out; - if (unshare_flags & CLONE_SYSVSEM) + /* + * CLONE_NEWIPC must also detach from the undolist: after switching + * to a new ipc namespace, the semaphore arrays from the old + * namespace are unreachable. + */ + if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM)) do_sysvsem = 1; if ((err = unshare_thread(unshare_flags))) goto bad_unshare_out; |