net: convert sock.sk_wmem_alloc 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.
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>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/atm/signaling.c b/net/atm/signaling.c
index f640a99..983c3a2 100644
--- a/net/atm/signaling.c
+++ b/net/atm/signaling.c
@@ -67,7 +67,7 @@ static int sigd_send(struct atm_vcc *vcc, struct sk_buff *skb)
struct sock *sk;
msg = (struct atmsvc_msg *) skb->data;
- atomic_sub(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
+ WARN_ON(refcount_sub_and_test(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc));
vcc = *(struct atm_vcc **) &msg->vcc;
pr_debug("%d (0x%lx)\n", (int)msg->type, (unsigned long)vcc);
sk = sk_atm(vcc);