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>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/atm/raw.c b/net/atm/raw.c
index 2e17e97a7a8b..821c0797553d 100644
--- a/net/atm/raw.c
+++ b/net/atm/raw.c
@@ -35,7 +35,7 @@ static void atm_pop_raw(struct atm_vcc *vcc, struct sk_buff *skb)
 
         pr_debug("(%d) %d -= %d\n",
                  vcc->vci, sk_wmem_alloc_get(sk), skb->truesize);
-        atomic_sub(skb->truesize, &sk->sk_wmem_alloc);
+        WARN_ON(refcount_sub_and_test(skb->truesize, &sk->sk_wmem_alloc));
         dev_kfree_skb_any(skb);
         sk->sk_write_space(sk);
 }