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authorEric Dumazet <edumazet@google.com>2017-08-31 16:48:22 -0700
committerDavid S. Miller <davem@davemloft.net>2017-09-01 20:22:03 -0700
commitc1d1b437816f0afa99202be3cb650c9d174667bc (patch)
tree14ee9ec0f2e759bb237b2a010aa56989874cc054 /net
parentdb5bce32fbe19f0c7482fb5a40a33178bbe7b11b (diff)
downloadlinux-c1d1b437816f0afa99202be3cb650c9d174667bc.tar.gz
net: convert (struct ubuf_info)->refcnt 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.

v2: added the change in drivers/vhost/net.c as spotted
by Willem.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/skbuff.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index a003f953a0a6..68065d7d383f 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -963,7 +963,7 @@ struct ubuf_info *sock_zerocopy_alloc(struct sock *sk, size_t size)
 	uarg->len = 1;
 	uarg->bytelen = size;
 	uarg->zerocopy = 1;
-	atomic_set(&uarg->refcnt, 1);
+	refcount_set(&uarg->refcnt, 1);
 	sock_hold(sk);
 
 	return uarg;
@@ -1086,7 +1086,7 @@ EXPORT_SYMBOL_GPL(sock_zerocopy_callback);
 
 void sock_zerocopy_put(struct ubuf_info *uarg)
 {
-	if (uarg && atomic_dec_and_test(&uarg->refcnt)) {
+	if (uarg && refcount_dec_and_test(&uarg->refcnt)) {
 		if (uarg->callback)
 			uarg->callback(uarg, uarg->zerocopy);
 		else
@@ -1483,7 +1483,7 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
 		if (skb_orphan_frags(skb, gfp_mask))
 			goto nofrags;
 		if (skb_zcopy(skb))
-			atomic_inc(&skb_uarg(skb)->refcnt);
+			refcount_inc(&skb_uarg(skb)->refcnt);
 		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
 			skb_frag_ref(skb, i);