net: Potential null skb->dev dereference
When doing "ifenslave -d bond0 eth0", there is chance to get NULL
dereference in netif_receive_skb(), because dev->master suddenly becomes
NULL after we tested it.
We should use ACCESS_ONCE() to avoid this (or rcu_dereference())
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/dev.c b/net/core/dev.c
index bcc490c..59d4394 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2483,6 +2483,7 @@
{
struct packet_type *ptype, *pt_prev;
struct net_device *orig_dev;
+ struct net_device *master;
struct net_device *null_or_orig;
struct net_device *null_or_bond;
int ret = NET_RX_DROP;
@@ -2503,11 +2504,12 @@
null_or_orig = NULL;
orig_dev = skb->dev;
- if (orig_dev->master) {
- if (skb_bond_should_drop(skb))
+ master = ACCESS_ONCE(orig_dev->master);
+ if (master) {
+ if (skb_bond_should_drop(skb, master))
null_or_orig = orig_dev; /* deliver only exact match */
else
- skb->dev = orig_dev->master;
+ skb->dev = master;
}
__get_cpu_var(netdev_rx_stat).total++;