From 14afee4b6092fde451ee17604e5f5c89da33e71e Mon Sep 17 00:00:00 2001
From: "Reshetova, Elena" <elena.reshetova@intel.com>
Date: Fri, 30 Jun 2017 13:08:00 +0300
Subject: 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>
---
 net/atm/raw.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'net/atm/raw.c')

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);
 }
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