ipoib: validate struct ipoib_cb size

To catch future errors sooner.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 8 insertions, 2 deletions

diff --git a/drivers/infiniband/ulp/ipoib/ipoib.h b/drivers/infiniband/ulp/ipoib/ipoib.h
index 3edce617c31b..d7562beb5423 100644
--- 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
index 1310acf6bf92..13e6e0431592 100644
--- 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);