path: root/ipc/sem.c
diff options
authorManfred Spraul <manfred@colorfullife.com>2008-04-29 01:00:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-29 08:06:14 -0700
commit9edff4ab1f8d82675277a04e359d0ed8bf14a7b7 (patch)
tree05e67ca13f78b0eff666a4424e03dd6d0fa964c7 /ipc/sem.c
parent44f564a4bf6ac70f2a84806203045cf515bc9367 (diff)
ipc: sysvsem: implement sys_unshare(CLONE_SYSVSEM)
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 1: add support for sys_unshare(CLONE_SYSVSEM) The original reason to not support it was the potential (inevitable?) confusion due to the fact that sys_unshare(CLONE_SYSVSEM) has the inverse meaning of clone(CLONE_SYSVSEM). Our two most reasonable options then appear to be (1) fully support CLONE_SYSVSEM, or (2) continue to refuse explicit CLONE_SYSVSEM, but always do it anyway on unshare(CLONE_SYSVSEM). This patch does (1). Changelog: Apr 16: SEH: switch to Manfred's alternative patch which removes the unshare_semundo() function which always refused CLONE_SYSVSEM. 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 'ipc/sem.c')
1 files changed, 1 insertions, 0 deletions
diff --git a/ipc/sem.c b/ipc/sem.c
index d56d3ab6bb8..e9418df5ff3 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -1250,6 +1250,7 @@ void exit_sem(struct task_struct *tsk)
undo_list = tsk->sysvsem.undo_list;
if (!undo_list)
+ tsk->sysvsem.undo_list = NULL;
if (!atomic_dec_and_test(&undo_list->refcnt))