Commit d54725cd authored by Pablo Neira Ayuso's avatar Pablo Neira Ayuso
Browse files

netfilter: nf_tables: support for multiple devices per netdev hook



This patch allows you to register one netdev basechain to multiple
devices. This adds a new NFTA_HOOK_DEVS netlink attribute to specify
the list of netdevices. Basechains store a list of hooks.

Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent bbaef955
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+2 −2
Original line number Diff line number Diff line
@@ -973,21 +973,21 @@ struct nft_hook {
 *	struct nft_base_chain - nf_tables base chain
 *
 *	@ops: netfilter hook ops
 *	@hook_list: list of netfilter hooks (for NFPROTO_NETDEV family)
 *	@type: chain type
 *	@policy: default policy
 *	@stats: per-cpu chain stats
 *	@chain: the chain
 *	@dev_name: device name that this base chain is attached to (if any)
 *	@flow_block: flow block (for hardware offload)
 */
struct nft_base_chain {
	struct nf_hook_ops		ops;
	struct list_head		hook_list;
	const struct nft_chain_type	*type;
	u8				policy;
	u8				flags;
	struct nft_stats __percpu	*stats;
	struct nft_chain		chain;
	char 				dev_name[IFNAMSIZ];
	struct flow_block		flow_block;
};

+2 −0
Original line number Diff line number Diff line
@@ -144,12 +144,14 @@ enum nft_list_attributes {
 * @NFTA_HOOK_HOOKNUM: netfilter hook number (NLA_U32)
 * @NFTA_HOOK_PRIORITY: netfilter hook priority (NLA_U32)
 * @NFTA_HOOK_DEV: netdevice name (NLA_STRING)
 * @NFTA_HOOK_DEVS: list of netdevices (NLA_NESTED)
 */
enum nft_hook_attributes {
	NFTA_HOOK_UNSPEC,
	NFTA_HOOK_HOOKNUM,
	NFTA_HOOK_PRIORITY,
	NFTA_HOOK_DEV,
	NFTA_HOOK_DEVS,
	__NFTA_HOOK_MAX
};
#define NFTA_HOOK_MAX		(__NFTA_HOOK_MAX - 1)
+232 −64
Original line number Diff line number Diff line
@@ -151,11 +151,64 @@ static void nft_set_trans_bind(const struct nft_ctx *ctx, struct nft_set *set)
	}
}

static int nft_netdev_register_hooks(struct net *net,
				     struct list_head *hook_list)
{
	struct nft_hook *hook;
	int err, j;

	j = 0;
	list_for_each_entry(hook, hook_list, list) {
		err = nf_register_net_hook(net, &hook->ops);
		if (err < 0)
			goto err_register;

		j++;
	}
	return 0;

err_register:
	list_for_each_entry(hook, hook_list, list) {
		if (j-- <= 0)
			break;

		nf_unregister_net_hook(net, &hook->ops);
	}
	return err;
}

static void nft_netdev_unregister_hooks(struct net *net,
					struct list_head *hook_list)
{
	struct nft_hook *hook;

	list_for_each_entry(hook, hook_list, list)
		nf_unregister_net_hook(net, &hook->ops);
}

static int nft_register_basechain_hooks(struct net *net, int family,
					struct nft_base_chain *basechain)
{
	if (family == NFPROTO_NETDEV)
		return nft_netdev_register_hooks(net, &basechain->hook_list);

	return nf_register_net_hook(net, &basechain->ops);
}

static void nft_unregister_basechain_hooks(struct net *net, int family,
					   struct nft_base_chain *basechain)
{
	if (family == NFPROTO_NETDEV)
		nft_netdev_unregister_hooks(net, &basechain->hook_list);
	else
		nf_unregister_net_hook(net, &basechain->ops);
}

static int nf_tables_register_hook(struct net *net,
				   const struct nft_table *table,
				   struct nft_chain *chain)
{
	const struct nft_base_chain *basechain;
	struct nft_base_chain *basechain;
	const struct nf_hook_ops *ops;

	if (table->flags & NFT_TABLE_F_DORMANT ||
@@ -168,14 +221,14 @@ static int nf_tables_register_hook(struct net *net,
	if (basechain->type->ops_register)
		return basechain->type->ops_register(net, ops);

	return nf_register_net_hook(net, ops);
	return nft_register_basechain_hooks(net, table->family, basechain);
}

static void nf_tables_unregister_hook(struct net *net,
				      const struct nft_table *table,
				      struct nft_chain *chain)
{
	const struct nft_base_chain *basechain;
	struct nft_base_chain *basechain;
	const struct nf_hook_ops *ops;

	if (table->flags & NFT_TABLE_F_DORMANT ||
@@ -187,7 +240,7 @@ static void nf_tables_unregister_hook(struct net *net,
	if (basechain->type->ops_unregister)
		return basechain->type->ops_unregister(net, ops);

	nf_unregister_net_hook(net, ops);
	nft_unregister_basechain_hooks(net, table->family, basechain);
}

static int nft_trans_table_add(struct nft_ctx *ctx, int msg_type)
@@ -742,7 +795,8 @@ static void nft_table_disable(struct net *net, struct nft_table *table, u32 cnt)
		if (cnt && i++ == cnt)
			break;

		nf_unregister_net_hook(net, &nft_base_chain(chain)->ops);
		nft_unregister_basechain_hooks(net, table->family,
					       nft_base_chain(chain));
	}
}

@@ -757,14 +811,16 @@ static int nf_tables_table_enable(struct net *net, struct nft_table *table)
		if (!nft_is_base_chain(chain))
			continue;

		err = nf_register_net_hook(net, &nft_base_chain(chain)->ops);
		err = nft_register_basechain_hooks(net, table->family,
						   nft_base_chain(chain));
		if (err < 0)
			goto err;
			goto err_register_hooks;

		i++;
	}
	return 0;
err:

err_register_hooks:
	if (i)
		nft_table_disable(net, table, i);
	return err;
@@ -1225,6 +1281,46 @@ nla_put_failure:
	return -ENOSPC;
}

static int nft_dump_basechain_hook(struct sk_buff *skb, int family,
				   const struct nft_base_chain *basechain)
{
	const struct nf_hook_ops *ops = &basechain->ops;
	struct nft_hook *hook, *first = NULL;
	struct nlattr *nest, *nest_devs;
	int n = 0;

	nest = nla_nest_start_noflag(skb, NFTA_CHAIN_HOOK);
	if (nest == NULL)
		goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_HOOK_HOOKNUM, htonl(ops->hooknum)))
		goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_HOOK_PRIORITY, htonl(ops->priority)))
		goto nla_put_failure;

	if (family == NFPROTO_NETDEV) {
		nest_devs = nla_nest_start_noflag(skb, NFTA_HOOK_DEVS);
		list_for_each_entry(hook, &basechain->hook_list, list) {
			if (!first)
				first = hook;

			if (nla_put_string(skb, NFTA_DEVICE_NAME,
					   hook->ops.dev->name))
				goto nla_put_failure;
			n++;
		}
		nla_nest_end(skb, nest_devs);

		if (n == 1 &&
		    nla_put_string(skb, NFTA_HOOK_DEV, first->ops.dev->name))
			goto nla_put_failure;
	}
	nla_nest_end(skb, nest);

	return 0;
nla_put_failure:
	return -1;
}

static int nf_tables_fill_chain_info(struct sk_buff *skb, struct net *net,
				     u32 portid, u32 seq, int event, u32 flags,
				     int family, const struct nft_table *table,
@@ -1253,21 +1349,10 @@ static int nf_tables_fill_chain_info(struct sk_buff *skb, struct net *net,

	if (nft_is_base_chain(chain)) {
		const struct nft_base_chain *basechain = nft_base_chain(chain);
		const struct nf_hook_ops *ops = &basechain->ops;
		struct nft_stats __percpu *stats;
		struct nlattr *nest;

		nest = nla_nest_start_noflag(skb, NFTA_CHAIN_HOOK);
		if (nest == NULL)
		if (nft_dump_basechain_hook(skb, family, basechain))
			goto nla_put_failure;
		if (nla_put_be32(skb, NFTA_HOOK_HOOKNUM, htonl(ops->hooknum)))
			goto nla_put_failure;
		if (nla_put_be32(skb, NFTA_HOOK_PRIORITY, htonl(ops->priority)))
			goto nla_put_failure;
		if (basechain->dev_name[0] &&
		    nla_put_string(skb, NFTA_HOOK_DEV, basechain->dev_name))
			goto nla_put_failure;
		nla_nest_end(skb, nest);

		if (nla_put_be32(skb, NFTA_CHAIN_POLICY,
				 htonl(basechain->policy)))
@@ -1485,6 +1570,7 @@ static void nf_tables_chain_free_chain_rules(struct nft_chain *chain)
static void nf_tables_chain_destroy(struct nft_ctx *ctx)
{
	struct nft_chain *chain = ctx->chain;
	struct nft_hook *hook, *next;

	if (WARN_ON(chain->use > 0))
		return;
@@ -1495,6 +1581,13 @@ static void nf_tables_chain_destroy(struct nft_ctx *ctx)
	if (nft_is_base_chain(chain)) {
		struct nft_base_chain *basechain = nft_base_chain(chain);

		if (ctx->family == NFPROTO_NETDEV) {
			list_for_each_entry_safe(hook, next,
						 &basechain->hook_list, list) {
				list_del_rcu(&hook->list);
				kfree_rcu(hook, rcu);
			}
		}
		module_put(basechain->type->owner);
		if (rcu_access_pointer(basechain->stats)) {
			static_branch_dec(&nft_counters_enabled);
@@ -1599,9 +1692,34 @@ struct nft_chain_hook {
	u32				num;
	s32				priority;
	const struct nft_chain_type	*type;
	struct net_device		*dev;
	struct list_head		list;
};

static int nft_chain_parse_netdev(struct net *net,
				  struct nlattr *tb[],
				  struct list_head *hook_list)
{
	struct nft_hook *hook;
	int err;

	if (tb[NFTA_HOOK_DEV]) {
		hook = nft_netdev_hook_alloc(net, tb[NFTA_HOOK_DEV]);
		if (IS_ERR(hook))
			return PTR_ERR(hook);

		list_add_tail(&hook->list, hook_list);
	} else if (tb[NFTA_HOOK_DEVS]) {
		err = nf_tables_parse_netdev_hooks(net, tb[NFTA_HOOK_DEVS],
						   hook_list);
		if (err < 0)
			return err;
	} else {
		return -EINVAL;
	}

	return 0;
}

static int nft_chain_parse_hook(struct net *net,
				const struct nlattr * const nla[],
				struct nft_chain_hook *hook, u8 family,
@@ -1609,7 +1727,6 @@ static int nft_chain_parse_hook(struct net *net,
{
	struct nlattr *ha[NFTA_HOOK_MAX + 1];
	const struct nft_chain_type *type;
	struct net_device *dev;
	int err;

	lockdep_assert_held(&net->nft.commit_mutex);
@@ -1647,23 +1764,14 @@ static int nft_chain_parse_hook(struct net *net,

	hook->type = type;

	hook->dev = NULL;
	INIT_LIST_HEAD(&hook->list);
	if (family == NFPROTO_NETDEV) {
		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) {
		err = nft_chain_parse_netdev(net, ha, &hook->list);
		if (err < 0) {
			module_put(type->owner);
			return -ENOENT;
			return err;
		}
		hook->dev = dev;
	} else if (ha[NFTA_HOOK_DEV]) {
	} else if (ha[NFTA_HOOK_DEV] || ha[NFTA_HOOK_DEVS]) {
		module_put(type->owner);
		return -EOPNOTSUPP;
	}
@@ -1673,6 +1781,12 @@ static int nft_chain_parse_hook(struct net *net,

static void nft_chain_release_hook(struct nft_chain_hook *hook)
{
	struct nft_hook *h, *next;

	list_for_each_entry_safe(h, next, &hook->list, list) {
		list_del(&h->list);
		kfree(h);
	}
	module_put(hook->type->owner);
}

@@ -1697,6 +1811,49 @@ static struct nft_rule **nf_tables_chain_alloc_rules(const struct nft_chain *cha
	return kvmalloc(alloc, GFP_KERNEL);
}

static void nft_basechain_hook_init(struct nf_hook_ops *ops, u8 family,
				    const struct nft_chain_hook *hook,
				    struct nft_chain *chain)
{
	ops->pf		= family;
	ops->hooknum	= hook->num;
	ops->priority	= hook->priority;
	ops->priv	= chain;
	ops->hook	= hook->type->hooks[ops->hooknum];
}

static int nft_basechain_init(struct nft_base_chain *basechain, u8 family,
			      struct nft_chain_hook *hook, u32 flags)
{
	struct nft_chain *chain;
	struct nft_hook *h;

	basechain->type = hook->type;
	INIT_LIST_HEAD(&basechain->hook_list);
	chain = &basechain->chain;

	if (family == NFPROTO_NETDEV) {
		list_splice_init(&hook->list, &basechain->hook_list);
		list_for_each_entry(h, &basechain->hook_list, list)
			nft_basechain_hook_init(&h->ops, family, hook, chain);

		basechain->ops.hooknum	= hook->num;
		basechain->ops.priority	= hook->priority;
	} else {
		nft_basechain_hook_init(&basechain->ops, family, hook, chain);
	}

	chain->flags |= NFT_BASE_CHAIN | flags;
	basechain->policy = NF_ACCEPT;
	if (chain->flags & NFT_CHAIN_HW_OFFLOAD &&
	    nft_chain_offload_priority(basechain) < 0)
		return -EOPNOTSUPP;

	flow_block_init(&basechain->flow_block);

	return 0;
}

static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask,
			      u8 policy, u32 flags)
{
@@ -1715,7 +1872,6 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask,

	if (nla[NFTA_CHAIN_HOOK]) {
		struct nft_chain_hook hook;
		struct nf_hook_ops *ops;

		err = nft_chain_parse_hook(net, nla, &hook, family, true);
		if (err < 0)
@@ -1726,9 +1882,7 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask,
			nft_chain_release_hook(&hook);
			return -ENOMEM;
		}

		if (hook.dev != NULL)
			strncpy(basechain->dev_name, hook.dev->name, IFNAMSIZ);
		chain = &basechain->chain;

		if (nla[NFTA_CHAIN_COUNTERS]) {
			stats = nft_stats_alloc(nla[NFTA_CHAIN_COUNTERS]);
@@ -1741,24 +1895,12 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask,
			static_branch_inc(&nft_counters_enabled);
		}

		basechain->type = hook.type;
		chain = &basechain->chain;

		ops		= &basechain->ops;
		ops->pf		= family;
		ops->hooknum	= hook.num;
		ops->priority	= hook.priority;
		ops->priv	= chain;
		ops->hook	= hook.type->hooks[ops->hooknum];
		ops->dev	= hook.dev;

		chain->flags |= NFT_BASE_CHAIN | flags;
		basechain->policy = NF_ACCEPT;
		if (chain->flags & NFT_CHAIN_HW_OFFLOAD &&
		    nft_chain_offload_priority(basechain) < 0)
			return -EOPNOTSUPP;

		flow_block_init(&basechain->flow_block);
		err = nft_basechain_init(basechain, family, &hook, flags);
		if (err < 0) {
			nft_chain_release_hook(&hook);
			kfree(basechain);
			return err;
		}
	} else {
		chain = kzalloc(sizeof(*chain), GFP_KERNEL);
		if (chain == NULL)
@@ -1818,6 +1960,25 @@ err1:
	return err;
}

static bool nft_hook_list_equal(struct list_head *hook_list1,
				struct list_head *hook_list2)
{
	struct nft_hook *hook;
	int n = 0, m = 0;

	n = 0;
	list_for_each_entry(hook, hook_list2, list) {
		if (!nft_hook_list_find(hook_list1, hook))
			return false;

		n++;
	}
	list_for_each_entry(hook, hook_list1, list)
		m++;

	return n == m;
}

static int nf_tables_updchain(struct nft_ctx *ctx, u8 genmask, u8 policy,
			      u32 flags)
{
@@ -1849,13 +2010,20 @@ static int nf_tables_updchain(struct nft_ctx *ctx, u8 genmask, u8 policy,
			return -EBUSY;
		}

		if (ctx->family == NFPROTO_NETDEV) {
			if (!nft_hook_list_equal(&basechain->hook_list,
						 &hook.list)) {
				nft_chain_release_hook(&hook);
				return -EBUSY;
			}
		} else {
			ops = &basechain->ops;
			if (ops->hooknum != hook.num ||
		    ops->priority != hook.priority ||
		    ops->dev != hook.dev) {
			    ops->priority != hook.priority) {
				nft_chain_release_hook(&hook);
				return -EBUSY;
			}
		}
		nft_chain_release_hook(&hook);
	}

+31 −13
Original line number Diff line number Diff line
@@ -317,38 +317,47 @@ static int nft_indr_block_offload_cmd(struct nft_base_chain *chain,
#define FLOW_SETUP_BLOCK TC_SETUP_BLOCK

static int nft_flow_block_chain(struct nft_base_chain *basechain,
				struct net_device *dev,
				const struct net_device *this_dev,
				enum flow_block_command cmd)
{
	struct net_device *dev;
	struct nft_hook *hook;
	int err;

	list_for_each_entry(hook, &basechain->hook_list, list) {
		dev = hook->ops.dev;
		if (this_dev && this_dev != dev)
			continue;

		if (dev->netdev_ops->ndo_setup_tc)
		return nft_block_offload_cmd(basechain, dev, cmd);
			err = nft_block_offload_cmd(basechain, dev, cmd);
		else
			err = nft_indr_block_offload_cmd(basechain, dev, cmd);

		if (err < 0)
			return err;
	}

	return nft_indr_block_offload_cmd(basechain, dev, cmd);
	return 0;
}

static int nft_flow_offload_chain(struct nft_chain *chain,
				  u8 *ppolicy,
static int nft_flow_offload_chain(struct nft_chain *chain, u8 *ppolicy,
				  enum flow_block_command cmd)
{
	struct nft_base_chain *basechain;
	struct net_device *dev;
	u8 policy;

	if (!nft_is_base_chain(chain))
		return -EOPNOTSUPP;

	basechain = nft_base_chain(chain);
	dev = basechain->ops.dev;
	if (!dev)
		return -EOPNOTSUPP;

	policy = ppolicy ? *ppolicy : basechain->policy;

	/* Only default policy to accept is supported for now. */
	if (cmd == FLOW_BLOCK_BIND && policy == NF_DROP)
		return -EOPNOTSUPP;

	return nft_flow_block_chain(basechain, dev, cmd);
	return nft_flow_block_chain(basechain, NULL, cmd);
}

int nft_flow_rule_offload_commit(struct net *net)
@@ -414,6 +423,7 @@ static struct nft_chain *__nft_offload_get_chain(struct net_device *dev)
{
	struct nft_base_chain *basechain;
	struct net *net = dev_net(dev);
	struct nft_hook *hook, *found;
	const struct nft_table *table;
	struct nft_chain *chain;

@@ -426,8 +436,16 @@ static struct nft_chain *__nft_offload_get_chain(struct net_device *dev)
			    !(chain->flags & NFT_CHAIN_HW_OFFLOAD))
				continue;

			found = NULL;
			basechain = nft_base_chain(chain);
			if (strncmp(basechain->dev_name, dev->name, IFNAMSIZ))
			list_for_each_entry(hook, &basechain->hook_list, list) {
				if (hook->ops.dev != dev)
					continue;

				found = hook;
				break;
			}
			if (!found)
				continue;

			return chain;
+26 −19
Original line number Diff line number Diff line
@@ -287,28 +287,35 @@ static void nft_netdev_event(unsigned long event, struct net_device *dev,
			     struct nft_ctx *ctx)
{
	struct nft_base_chain *basechain = nft_base_chain(ctx->chain);
	struct nft_hook *hook, *found = NULL;
	int n = 0;

	switch (event) {
	case NETDEV_UNREGISTER:
		if (strcmp(basechain->dev_name, dev->name) != 0)
	if (event != NETDEV_UNREGISTER)
		return;

		/* UNREGISTER events are also happpening on netns exit.
		 *
		 * Altough nf_tables core releases all tables/chains, only
		 * this event handler provides guarantee that
		 * basechain.ops->dev is still accessible, so we cannot
		 * skip exiting net namespaces.
		 */
		__nft_release_basechain(ctx);
		break;
	case NETDEV_CHANGENAME:
		if (dev->ifindex != basechain->ops.dev->ifindex)
	list_for_each_entry(hook, &basechain->hook_list, list) {
		if (hook->ops.dev == dev)
			found = hook;

		n++;
	}
	if (!found)
		return;

		strncpy(basechain->dev_name, dev->name, IFNAMSIZ);
		break;
	if (n > 1) {
		nf_unregister_net_hook(ctx->net, &found->ops);
		list_del_rcu(&found->list);
		kfree_rcu(found, rcu);
		return;
	}

	/* UNREGISTER events are also happening on netns exit.
	 *
	 * Although nf_tables core releases all tables/chains, only this event
	 * handler provides guarantee that hook->ops.dev is still accessible,
	 * so we cannot skip exiting net namespaces.
	 */
	__nft_release_basechain(ctx);
}

static int nf_tables_netdev_event(struct notifier_block *this,