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xfrm: Fix potential null pointer dereference in xdst_queue_output 

The net_device might be not set on the skb when we try refcounting.
This leads to a null pointer dereference in xdst_queue_output().
It turned out that the refcount to the net_device is not needed
after all. The dst_entry has a refcount to the net_device before
we queue the skb, so it can't go away. Therefore we can remove the
refcount on queueing to fix the null pointer dereference.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
hifive-unleashed-5.1
Steffen Klassert 2013-08-28 08:47:14 +02:00
parent 9c9c9ad5fa
commit 302a50bc94
1 changed files with 1 additions and 8 deletions
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9
net/xfrm/xfrm_policy.c
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@ -320,10 +320,8 @@ static void xfrm_queue_purge(struct sk_buff_head *list)
{
struct sk_buff *skb;
while ((skb = skb_dequeue(list)) != NULL) {
dev_put(skb->dev);
while ((skb = skb_dequeue(list)) != NULL)
kfree_skb(skb);
}
}
/* Rule must be locked. Release descentant resources, announce
@ -1758,7 +1756,6 @@ static void xfrm_policy_queue_process(unsigned long arg)
struct sk_buff *skb;
struct sock *sk;
struct dst_entry *dst;
struct net_device *dev;
struct xfrm_policy *pol = (struct xfrm_policy *)arg;
struct xfrm_policy_queue *pq = &pol->polq;
struct flowi fl;
@ -1805,7 +1802,6 @@ static void xfrm_policy_queue_process(unsigned long arg)
dst = xfrm_lookup(xp_net(pol), skb_dst(skb)->path,
&fl, skb->sk, 0);
if (IS_ERR(dst)) {
dev_put(skb->dev);
kfree_skb(skb);
continue;
}
@ -1814,9 +1810,7 @@ static void xfrm_policy_queue_process(unsigned long arg)
skb_dst_drop(skb);
skb_dst_set(skb, dst);
dev = skb->dev;
err = dst_output(skb);
dev_put(dev);
}
return;
@ -1839,7 +1833,6 @@ static int xdst_queue_output(struct sk_buff *skb)
}
skb_dst_force(skb);
dev_hold(skb->dev);
spin_lock_bh(&pq->hold_queue.lock);