ipc: convert kern_ipc_perm.refcount from atomic_t to refcount_t
refcount_t type and corresponding API should be used instead of atomic_t
when the variable is used as a reference counter. This allows to avoid
accidental refcounter overflows that might lead to use-after-free
situations.
Link: http://lkml.kernel.org/r/1499417992-3238-4-git-send-email-elena.reshetova@intel.com
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: <arozansk@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/ipc/util.c b/ipc/util.c
index 1a2cb02..069bb22 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -232,7 +232,7 @@
idr_preload(GFP_KERNEL);
- atomic_set(&new->refcount, 1);
+ refcount_set(&new->refcount, 1);
spin_lock_init(&new->lock);
new->deleted = false;
rcu_read_lock();
@@ -397,13 +397,13 @@
int ipc_rcu_getref(struct kern_ipc_perm *ptr)
{
- return atomic_inc_not_zero(&ptr->refcount);
+ return refcount_inc_not_zero(&ptr->refcount);
}
void ipc_rcu_putref(struct kern_ipc_perm *ptr,
void (*func)(struct rcu_head *head))
{
- if (!atomic_dec_and_test(&ptr->refcount))
+ if (!refcount_dec_and_test(&ptr->refcount))
return;
call_rcu(&ptr->rcu, func);