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

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commit d5485d9dd24e1d04e5509916515260186eb1455c upstream.

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: 66ba215cb513 ("neigh: fix possible DoS due to net iface start/stop loop")
Suggested-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Yang Yingliang 2022-08-22 10:53:46 +08:00 committed by Greg Kroah-Hartman
parent 25a80e7284
commit 0052348329
1 changed files with 8 additions and 2 deletions
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10
net/core/neighbour.c
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@ -282,21 +282,27 @@ static int neigh_del_timer(struct neighbour *n)
static void pneigh_queue_purge(struct sk_buff_head *list, struct net *net) static void pneigh_queue_purge(struct sk_buff_head *list, struct net *net)
{ {
struct sk_buff_head tmp;
unsigned long flags; unsigned long flags;
struct sk_buff *skb; struct sk_buff *skb;
skb_queue_head_init(&tmp);
spin_lock_irqsave(&list->lock, flags); spin_lock_irqsave(&list->lock, flags);
skb = skb_peek(list); skb = skb_peek(list);
while (skb != NULL) { while (skb != NULL) {
struct sk_buff *skb_next = skb_peek_next(skb, list); struct sk_buff *skb_next = skb_peek_next(skb, list);
if (net == NULL || net_eq(dev_net(skb->dev), net)) { if (net == NULL || net_eq(dev_net(skb->dev), net)) {
__skb_unlink(skb, list); __skb_unlink(skb, list);
dev_put(skb->dev); __skb_queue_tail(&tmp, skb);
kfree_skb(skb);
} }
skb = skb_next; skb = skb_next;
} }
spin_unlock_irqrestore(&list->lock, flags); 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, static void neigh_flush_dev(struct neigh_table *tbl, struct net_device *dev,