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| author | Serge E. Hallyn <serue@us.ibm.com> | 2008-04-29 01:01:00 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-29 08:06:14 -0700 |
| commit | 02fdb36ae7f55db7757b623acd27a62d5000d755 (patch) | |
| tree | 9d96036a7ee174a2828fbb7497a9f365f4f148a1 | |
| parent | 6013f67fc1a4c7fa5bcab2d39c1eaa3e260c7ac1 (diff) | |
| download | linux-02fdb36ae7f55db7757b623acd27a62d5000d755.tar.gz linux-02fdb36ae7f55db7757b623acd27a62d5000d755.tar.bz2 linux-02fdb36ae7f55db7757b623acd27a62d5000d755.zip | |
ipc: sysvsem: refuse clone(CLONE_SYSVSEM|CLONE_NEWIPC)
CLONE_NEWIPC|CLONE_SYSVSEM interaction isn't handled properly. This can cause
a kernel memory corruption. CLONE_NEWIPC must detach from the existing undo
lists.
Fix, part 3: refuse clone(CLONE_SYSVSEM|CLONE_NEWIPC).
With unshare, specifying CLONE_SYSVSEM means unshare the sysvsem. So it seems
reasonable that CLONE_NEWIPC without CLONE_SYSVSEM would just imply
CLONE_SYSVSEM.
However with clone, specifying CLONE_SYSVSEM means *share* the sysvsem. So
calling clone(CLONE_SYSVSEM|CLONE_NEWIPC) is explicitly asking for something
we can't allow. So return -EINVAL in that case.
[akpm@linux-foundation.org: cleanups]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Manfred Spraul <manfred@colorfullife.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>
| -rw-r--r-- | kernel/nsproxy.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c index f5d332cf8c63..adc785146a1c 100644 --- a/kernel/nsproxy.c +++ b/kernel/nsproxy.c @@ -139,6 +139,18 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk) goto out; } + /* + * CLONE_NEWIPC must detach from the undolist: after switching + * to a new ipc namespace, the semaphore arrays from the old + * namespace are unreachable. In clone parlance, CLONE_SYSVSEM + * means share undolist with parent, so we must forbid using + * it along with CLONE_NEWIPC. + */ + if ((flags & CLONE_NEWIPC) && (flags & CLONE_SYSVSEM)) { + err = -EINVAL; + goto out; + } + new_ns = create_new_namespaces(flags, tsk, tsk->fs); if (IS_ERR(new_ns)) { err = PTR_ERR(new_ns); |