ipoib: validate struct ipoib_cb size

edumazet · davem330 · commit b49fe36208b4 · 2014-09-22T14:29:55.000-04:00
To catch future errors sooner.

Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
diff --git a/drivers/infiniband/ulp/ipoib/ipoib.h b/drivers/infiniband/ulp/ipoib/ipoib.h
@@ -131,6 +131,12 @@ struct ipoib_cb {
 	u8			hwaddr[INFINIBAND_ALEN];
 };
 
+static inline struct ipoib_cb *ipoib_skb_cb(const struct sk_buff *skb)
+{
+	BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct ipoib_cb));
+	return (struct ipoib_cb *)skb->cb;
+}
+
 /* Used for all multicast joins (broadcast, IPv4 mcast and IPv6 mcast) */
 struct ipoib_mcast {
 	struct ib_sa_mcmember_rec mcmember;
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -716,7 +716,7 @@ static int ipoib_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct ipoib_dev_priv *priv = netdev_priv(dev);
 	struct ipoib_neigh *neigh;
-	struct ipoib_cb *cb = (struct ipoib_cb *) skb->cb;
+	struct ipoib_cb *cb = ipoib_skb_cb(skb);
 	struct ipoib_header *header;
 	unsigned long flags;
 
@@ -813,7 +813,7 @@ static int ipoib_hard_header(struct sk_buff *skb,
 			     const void *daddr, const void *saddr, unsigned len)
 {
 	struct ipoib_header *header;
-	struct ipoib_cb *cb = (struct ipoib_cb *) skb->cb;
+	struct ipoib_cb *cb = ipoib_skb_cb(skb);
 
 	header = (struct ipoib_header *) skb_push(skb, sizeof *header);
 

Original file line number	Diff line number	Diff line change
`@@ -716,7 +716,7 @@ static int ipoib_start_xmit(struct sk_buff skb, struct net_device dev)`
`716`	`716`	`{`
`717`	`717`	`struct ipoib_dev_priv *priv = netdev_priv(dev);`
`718`	`718`	`struct ipoib_neigh *neigh;`
`719`		`- struct ipoib_cb cb = (struct ipoib_cb ) skb->cb;`
	`719`	`+ struct ipoib_cb *cb = ipoib_skb_cb(skb);`
`720`	`720`	`struct ipoib_header *header;`
`721`	`721`	`unsigned long flags;`
`722`	`722`
`@@ -813,7 +813,7 @@ static int ipoib_hard_header(struct sk_buff *skb,`
`813`	`813`	`const void daddr, const void saddr, unsigned len)`
`814`	`814`	`{`
`815`	`815`	`struct ipoib_header *header;`
`816`		`- struct ipoib_cb cb = (struct ipoib_cb ) skb->cb;`
	`816`	`+ struct ipoib_cb *cb = ipoib_skb_cb(skb);`
`817`	`817`
`818`	`818`	`header = (struct ipoib_header ) skb_push(skb, sizeof header);`
`819`	`819`