diff options
| author | Manfred Spraul <manfred@colorfullife.com> | 2017-07-12 14:35:19 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-12 16:26:02 -0700 |
| commit | 51c23b7b7db52493d4fc869cec8c3e8fe27bfcd3 (patch) | |
| tree | 087792a59b22078d3e88f70ad413ed5401403d6e | |
| parent | a2642f8770993a1598500bb6a8082b7c32faff8b (diff) | |
| download | lwn-51c23b7b7db52493d4fc869cec8c3e8fe27bfcd3.tar.gz lwn-51c23b7b7db52493d4fc869cec8c3e8fe27bfcd3.zip | |
ipc/msg.c: avoid ipc_rcu_putref for failed ipc_addid()
Loosely based on a patch from Kees Cook <keescook@chromium.org>:
- id and retval can be merged
- if ipc_addid() fails, then use call_rcu() directly.
The difference is that call_rcu is used for failed ipc_addid() calls, to
continue to guaranteed an rcu delay for security_msg_queue_free().
Link: http://lkml.kernel.org/r/20170525185107.12869-16-manfred@colorfullife.com
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | ipc/msg.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/ipc/msg.c b/ipc/msg.c index 10094a731b8e..cd90bfde89a4 100644 --- a/ipc/msg.c +++ b/ipc/msg.c @@ -132,7 +132,7 @@ static struct msg_queue *msg_alloc(void) static int newque(struct ipc_namespace *ns, struct ipc_params *params) { struct msg_queue *msq; - int id, retval; + int retval; key_t key = params->key; int msgflg = params->flg; @@ -160,10 +160,10 @@ static int newque(struct ipc_namespace *ns, struct ipc_params *params) INIT_LIST_HEAD(&msq->q_senders); /* ipc_addid() locks msq upon success. */ - id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni); - if (id < 0) { - ipc_rcu_putref(&msq->q_perm, msg_rcu_free); - return id; + retval = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni); + if (retval < 0) { + call_rcu(&msq->q_perm.rcu, msg_rcu_free); + return retval; } ipc_unlock_object(&msq->q_perm); |