From 9edff4ab1f8d82675277a04e359d0ed8bf14a7b7 Mon Sep 17 00:00:00 2001 From: Manfred Spraul Date: Tue, 29 Apr 2008 01:00:57 -0700 Subject: 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 Signed-off-by: Serge E. Hallyn Acked-by: "Eric W. Biederman" Cc: Pavel Emelyanov Cc: Michael Kerrisk Cc: Pierre Peiffer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- ipc/sem.c | 1 + 1 file changed, 1 insertion(+) (limited to 'ipc/sem.c') diff --git a/ipc/sem.c b/ipc/sem.c index d56d3ab6bb8a..e9418df5ff3e 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) return; + tsk->sysvsem.undo_list = NULL; if (!atomic_dec_and_test(&undo_list->refcnt)) return; -- cgit v1.2.3-58-ga151