Commit d5485d9d authored by Yang Yingliang's avatar Yang Yingliang Committed by David S. Miller
Browse files

net: neigh: don't call kfree_skb() under spin_lock_irqsave() 



It is not allowed to call kfree_skb() from hardware interrupt
context or with interrupts being disabled. So add all skb to
a tmp list, then free them after spin_unlock_irqrestore() at
once.

Fixes: 66ba215c ("neigh: fix possible DoS due to net iface start/stop loop")
Suggested-by: default avatarDenis V. Lunev <den@openvz.org>
Signed-off-by: default avatarYang Yingliang <yangyingliang@huawei.com>
Reviewed-by: default avatarNikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 550e9a4d

net/core/neighbour.c

+9 −3
Original line number Diff line number Diff line
@@ -309,14 +309,17 @@ static int neigh_del_timer(struct neighbour *n) 


static void pneigh_queue_purge(struct sk_buff_head *list, struct net *net)

{

	struct sk_buff_head tmp;

	unsigned long flags;

	struct sk_buff *skb;



	skb_queue_head_init(&tmp);

	spin_lock_irqsave(&list->lock, flags);

	skb = skb_peek(list);

	while (skb != NULL) {

		struct sk_buff *skb_next = skb_peek_next(skb, list);

		struct net_device *dev = skb->dev;



		if (net == NULL || net_eq(dev_net(dev), net)) {

			struct in_device *in_dev;
@@ -326,13 +329,16 @@ static void pneigh_queue_purge(struct sk_buff_head *list, struct net *net) 
				in_dev->arp_parms->qlen--;

			rcu_read_unlock();

			__skb_unlink(skb, list);



			dev_put(dev);

			kfree_skb(skb);

			__skb_queue_tail(&tmp, skb);

		}

		skb = skb_next;

	}

	spin_unlock_irqrestore(&list->lock, flags);



	while ((skb = __skb_dequeue(&tmp))) {

		dev_put(skb->dev);

		kfree_skb(skb);

	}

}



static void neigh_flush_dev(struct neigh_table *tbl, struct net_device *dev,