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netfilter: nf_dup_netdev: add and use recursion counter
Now that the egress function can be called from egress hook, we need
to avoid recursive calls into the nf_tables traverser, else crash.
Fixes: f87b9464d1
("netfilter: nft_fwd_netdev: Support egress hook")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
parent
574a5b85dc
commit
fcd53c51d0
@ -13,20 +13,31 @@
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#include <net/netfilter/nf_tables_offload.h>
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#include <net/netfilter/nf_dup_netdev.h>
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#define NF_RECURSION_LIMIT 2
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static DEFINE_PER_CPU(u8, nf_dup_skb_recursion);
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static void nf_do_netdev_egress(struct sk_buff *skb, struct net_device *dev,
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enum nf_dev_hooks hook)
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{
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if (__this_cpu_read(nf_dup_skb_recursion) > NF_RECURSION_LIMIT)
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goto err;
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if (hook == NF_NETDEV_INGRESS && skb_mac_header_was_set(skb)) {
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if (skb_cow_head(skb, skb->mac_len)) {
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kfree_skb(skb);
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return;
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}
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if (skb_cow_head(skb, skb->mac_len))
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goto err;
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skb_push(skb, skb->mac_len);
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}
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skb->dev = dev;
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skb_clear_tstamp(skb);
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__this_cpu_inc(nf_dup_skb_recursion);
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dev_queue_xmit(skb);
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__this_cpu_dec(nf_dup_skb_recursion);
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return;
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err:
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kfree_skb(skb);
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}
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void nf_fwd_netdev_egress(const struct nft_pktinfo *pkt, int oif)
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