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net: Potential null skb->dev dereference

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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>
This commit is contained in:
Eric Dumazet
2010-03-18 21:16:45 -07:00
committed by David S. Miller
parent 54d259d474
commit 0641e4fbf2
3 changed files with 11 additions and 9 deletions
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8
net/core/dev.c
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@@ -2483,6 +2483,7 @@ int netif_receive_skb(struct sk_buff *skb)
{
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 @@ int netif_receive_skb(struct sk_buff *skb)
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++;