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Commit 508f8ccd authored by Pablo Neira Ayuso's avatar Pablo Neira Ayuso
Browse files

netfilter: nf_tables: introduce nft_chain_parse_hook() 



Introduce a new function to wrap the code that parses the chain hook
configuration so we can reuse this code to validate chain updates.

Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent b43f9569

net/netfilter/nf_tables_api.c

+89 −63
Original line number Diff line number Diff line
@@ -1196,6 +1196,83 @@ static void nf_tables_chain_destroy(struct nft_chain *chain) 
	}

}



struct nft_chain_hook {

	u32				num;

	u32				priority;

	const struct nf_chain_type	*type;

	struct net_device		*dev;

};



static int nft_chain_parse_hook(struct net *net,

				const struct nlattr * const nla[],

				struct nft_af_info *afi,

				struct nft_chain_hook *hook, bool create)

{

	struct nlattr *ha[NFTA_HOOK_MAX + 1];

	const struct nf_chain_type *type;

	struct net_device *dev;

	int err;



	err = nla_parse_nested(ha, NFTA_HOOK_MAX, nla[NFTA_CHAIN_HOOK],

			       nft_hook_policy);

	if (err < 0)

		return err;



	if (ha[NFTA_HOOK_HOOKNUM] == NULL ||

	    ha[NFTA_HOOK_PRIORITY] == NULL)

		return -EINVAL;



	hook->num = ntohl(nla_get_be32(ha[NFTA_HOOK_HOOKNUM]));

	if (hook->num >= afi->nhooks)

		return -EINVAL;



	hook->priority = ntohl(nla_get_be32(ha[NFTA_HOOK_PRIORITY]));



	type = chain_type[afi->family][NFT_CHAIN_T_DEFAULT];

	if (nla[NFTA_CHAIN_TYPE]) {

		type = nf_tables_chain_type_lookup(afi, nla[NFTA_CHAIN_TYPE],

						   create);

		if (IS_ERR(type))

			return PTR_ERR(type);

	}

	if (!(type->hook_mask & (1 << hook->num)))

		return -EOPNOTSUPP;

	if (!try_module_get(type->owner))

		return -ENOENT;



	hook->type = type;



	hook->dev = NULL;

	if (afi->flags & NFT_AF_NEEDS_DEV) {

		char ifname[IFNAMSIZ];



		if (!ha[NFTA_HOOK_DEV]) {

			module_put(type->owner);

			return -EOPNOTSUPP;

		}



		nla_strlcpy(ifname, ha[NFTA_HOOK_DEV], IFNAMSIZ);

		dev = dev_get_by_name(net, ifname);

		if (!dev) {

			module_put(type->owner);

			return -ENOENT;

		}

		hook->dev = dev;

	} else if (ha[NFTA_HOOK_DEV]) {

		module_put(type->owner);

		return -EOPNOTSUPP;

	}



	return 0;

}



static void nft_chain_release_hook(struct nft_chain_hook *hook)

{

	module_put(hook->type->owner);

	if (hook->dev != NULL)

		dev_put(hook->dev);

}



static int nf_tables_newchain(struct net *net, struct sock *nlsk,

			      struct sk_buff *skb, const struct nlmsghdr *nlh,

			      const struct nlattr * const nla[])
@@ -1206,10 +1283,8 @@ static int nf_tables_newchain(struct net *net, struct sock *nlsk, 
	struct nft_table *table;

	struct nft_chain *chain;

	struct nft_base_chain *basechain = NULL;

	struct nlattr *ha[NFTA_HOOK_MAX + 1];

	u8 genmask = nft_genmask_next(net);

	int family = nfmsg->nfgen_family;

	struct net_device *dev = NULL;

	u8 policy = NF_ACCEPT;

	u64 handle = 0;

	unsigned int i;
@@ -1320,102 +1395,53 @@ static int nf_tables_newchain(struct net *net, struct sock *nlsk, 
		return -EOVERFLOW;



	if (nla[NFTA_CHAIN_HOOK]) {

		const struct nf_chain_type *type;

		struct nft_chain_hook hook;

		struct nf_hook_ops *ops;

		nf_hookfn *hookfn;

		u32 hooknum, priority;



		type = chain_type[family][NFT_CHAIN_T_DEFAULT];

		if (nla[NFTA_CHAIN_TYPE]) {

			type = nf_tables_chain_type_lookup(afi,

							   nla[NFTA_CHAIN_TYPE],

							   create);

			if (IS_ERR(type))

				return PTR_ERR(type);

		}



		err = nla_parse_nested(ha, NFTA_HOOK_MAX, nla[NFTA_CHAIN_HOOK],

				       nft_hook_policy);

		err = nft_chain_parse_hook(net, nla, afi, &hook, create);

		if (err < 0)

			return err;

		if (ha[NFTA_HOOK_HOOKNUM] == NULL ||

		    ha[NFTA_HOOK_PRIORITY] == NULL)

			return -EINVAL;



		hooknum = ntohl(nla_get_be32(ha[NFTA_HOOK_HOOKNUM]));

		if (hooknum >= afi->nhooks)

			return -EINVAL;

		priority = ntohl(nla_get_be32(ha[NFTA_HOOK_PRIORITY]));



		if (!(type->hook_mask & (1 << hooknum)))

			return -EOPNOTSUPP;

		if (!try_module_get(type->owner))

			return -ENOENT;

		hookfn = type->hooks[hooknum];



		if (afi->flags & NFT_AF_NEEDS_DEV) {

			char ifname[IFNAMSIZ];



			if (!ha[NFTA_HOOK_DEV]) {

				module_put(type->owner);

				return -EOPNOTSUPP;

			}



			nla_strlcpy(ifname, ha[NFTA_HOOK_DEV], IFNAMSIZ);

			dev = dev_get_by_name(net, ifname);

			if (!dev) {

				module_put(type->owner);

				return -ENOENT;

			}

		} else if (ha[NFTA_HOOK_DEV]) {

			module_put(type->owner);

			return -EOPNOTSUPP;

		}



		basechain = kzalloc(sizeof(*basechain), GFP_KERNEL);

		if (basechain == NULL) {

			module_put(type->owner);

			if (dev != NULL)

				dev_put(dev);

			nft_chain_release_hook(&hook);

			return -ENOMEM;

		}



		if (dev != NULL)

			strncpy(basechain->dev_name, dev->name, IFNAMSIZ);

		if (hook.dev != NULL)

			strncpy(basechain->dev_name, hook.dev->name, IFNAMSIZ);



		if (nla[NFTA_CHAIN_COUNTERS]) {

			stats = nft_stats_alloc(nla[NFTA_CHAIN_COUNTERS]);

			if (IS_ERR(stats)) {

				module_put(type->owner);

				nft_chain_release_hook(&hook);

				kfree(basechain);

				if (dev != NULL)

					dev_put(dev);

				return PTR_ERR(stats);

			}

			basechain->stats = stats;

		} else {

			stats = netdev_alloc_pcpu_stats(struct nft_stats);

			if (stats == NULL) {

				module_put(type->owner);

				nft_chain_release_hook(&hook);

				kfree(basechain);

				if (dev != NULL)

					dev_put(dev);

				return -ENOMEM;

			}

			rcu_assign_pointer(basechain->stats, stats);

		}



		basechain->type = type;

		hookfn = hook.type->hooks[hook.num];

		basechain->type = hook.type;

		chain = &basechain->chain;



		for (i = 0; i < afi->nops; i++) {

			ops = &basechain->ops[i];

			ops->pf		= family;

			ops->hooknum	= hooknum;

			ops->priority	= priority;

			ops->hooknum	= hook.num;

			ops->priority	= hook.priority;

			ops->priv	= chain;

			ops->hook	= afi->hooks[ops->hooknum];

			ops->dev	= dev;

			ops->dev	= hook.dev;

			if (hookfn)

				ops->hook = hookfn;

			if (afi->hook_ops_init)