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authorManfred Spraul <manfred@colorfullife.com>2017-07-12 14:35:13 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-12 16:26:02 -0700
commit2ec55f8024db859d70f14c26e91ca044328dd50d (patch)
tree8e37263fd21347b0f173d38697f856547ea829b7 /ipc/sem.c
parentipc/util: drop ipc_rcu_alloc() (diff)
downloadlinux-dev-2ec55f8024db859d70f14c26e91ca044328dd50d.tar.xz
linux-dev-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/sem.c')
-rw-r--r--ipc/sem.c9
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;