Messages in this thread Patch in this message | | | From | Manfred Spraul <> | Subject | [PATCH 13/20] ipc/sem.c: Avoid ipc_rcu_putref for failed ipc_addid() | Date | Thu, 25 May 2017 20:51:00 +0200 |
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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().
Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Kees Cook <keescook@chromium.org> --- ipc/sem.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/ipc/sem.c b/ipc/sem.c index 445a5b5..2b2ed56 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; -- 2.9.3
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