df122f58b8
The caller assumes that < 0 means that skb was stolen (or free'd). All other return values continue skb processing. nf_hook_slow returns 3 different return value types: A) a (negative) errno value: the skb was dropped (NF_DROP, e.g. by iptables '-j DROP' rule). B) 0. The skb was stolen by the hook or queued to userspace. C) 1. all hooks returned NF_ACCEPT so the caller should invoke the okfn so packet processing can continue. nft ingress facility currently doesn't have the 'okfn' that the NF_HOOK() macros use; there is no nfqueue support either. So 1 means that nf_hook_ingress() caller should go on processing the skb. In order to allow use of NF_STOLEN from ingress we need to translate this to an errno number, else we'd crash because we continue with already-free'd (or about to be free-d) skb. The errno value isn't checked, its just important that its less than 0, so return -1. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
58 lines
1.4 KiB
C
58 lines
1.4 KiB
C
#ifndef _NETFILTER_INGRESS_H_
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#define _NETFILTER_INGRESS_H_
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#include <linux/netfilter.h>
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#include <linux/netdevice.h>
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#ifdef CONFIG_NETFILTER_INGRESS
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static inline bool nf_hook_ingress_active(const struct sk_buff *skb)
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{
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#ifdef HAVE_JUMP_LABEL
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if (!static_key_false(&nf_hooks_needed[NFPROTO_NETDEV][NF_NETDEV_INGRESS]))
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return false;
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#endif
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return rcu_access_pointer(skb->dev->nf_hooks_ingress);
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}
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/* caller must hold rcu_read_lock */
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static inline int nf_hook_ingress(struct sk_buff *skb)
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{
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struct nf_hook_entry *e = rcu_dereference(skb->dev->nf_hooks_ingress);
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struct nf_hook_state state;
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int ret;
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/* Must recheck the ingress hook head, in the event it became NULL
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* after the check in nf_hook_ingress_active evaluated to true.
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*/
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if (unlikely(!e))
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return 0;
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nf_hook_state_init(&state, NF_NETDEV_INGRESS,
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NFPROTO_NETDEV, skb->dev, NULL, NULL,
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dev_net(skb->dev), NULL);
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ret = nf_hook_slow(skb, &state, e);
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if (ret == 0)
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return -1;
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return ret;
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}
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static inline void nf_hook_ingress_init(struct net_device *dev)
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{
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RCU_INIT_POINTER(dev->nf_hooks_ingress, NULL);
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}
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#else /* CONFIG_NETFILTER_INGRESS */
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static inline int nf_hook_ingress_active(struct sk_buff *skb)
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{
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return 0;
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}
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static inline int nf_hook_ingress(struct sk_buff *skb)
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{
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return 0;
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}
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static inline void nf_hook_ingress_init(struct net_device *dev) {}
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#endif /* CONFIG_NETFILTER_INGRESS */
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#endif /* _NETFILTER_INGRESS_H_ */
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