diff options
| author | Manfred Spraul <manfred@colorfullife.com> | 2017-07-12 14:35:13 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-12 16:26:02 -0700 |
| commit | 2ec55f8024db859d70f14c26e91ca044328dd50d (patch) | |
| tree | 8e37263fd21347b0f173d38697f856547ea829b7 /ipc | |
| parent | c3f6fb6fe4e638a58eae558cb209c463cd46c2fc (diff) | |
| download | lwn-2ec55f8024db859d70f14c26e91ca044328dd50d.tar.gz lwn-2ec55f8024db859d70f14c26e91ca044328dd50d.zip | |
ipc/sem.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_sem_free().
Link: http://lkml.kernel.org/r/20170525185107.12869-14-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>
Diffstat (limited to 'ipc')
| -rw-r--r-- | ipc/sem.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/ipc/sem.c b/ipc/sem.c index 445a5b5eb88f..2b2ed56e0fde 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -479,7 +479,6 @@ static struct sem_array *sem_alloc(size_t nsems) */ static int newary(struct ipc_namespace *ns, struct ipc_params *params) { - int id; int retval; struct sem_array *sma; key_t key = params->key; @@ -520,10 +519,10 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params) sma->sem_nsems = nsems; sma->sem_ctime = get_seconds(); - id = ipc_addid(&sem_ids(ns), &sma->sem_perm, ns->sc_semmni); - if (id < 0) { - ipc_rcu_putref(&sma->sem_perm, sem_rcu_free); - return id; + retval = ipc_addid(&sem_ids(ns), &sma->sem_perm, ns->sc_semmni); + if (retval < 0) { + call_rcu(&sma->sem_perm.rcu, sem_rcu_free); + return retval; } ns->used_sems += nsems; |