netfilter: nf_tables: destroy basechain and rules on netdevice removal

If the netdevice is destroyed, the resources that are attached should
be released too as they belong to the device that is now gone.

Suggested-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/net/netfilter/nf_tables.h

@@ -821,10 +821,7 @@ static inline struct nft_base_chain *nft_base_chain(const struct nft_chain *chai
 	return container_of(chain, struct nft_base_chain, chain);
 }
 
-int nft_register_basechain(struct nft_base_chain *basechain,
-			   unsigned int hook_nops);
-void nft_unregister_basechain(struct nft_base_chain *basechain,
-			      unsigned int hook_nops);
+int __nft_release_basechain(struct nft_ctx *ctx);
 
 unsigned int nft_do_chain(struct nft_pktinfo *pkt, void *priv);
 

net/netfilter/nf_tables_api.c

@@ -131,8 +131,8 @@ static void nft_trans_destroy(struct nft_trans *trans)
 	kfree(trans);
 }
 
-int nft_register_basechain(struct nft_base_chain *basechain,
-			   unsigned int hook_nops)
+static int nft_register_basechain(struct nft_base_chain *basechain,
+				  unsigned int hook_nops)
 {
 	struct net *net = read_pnet(&basechain->pnet);
 
@@ -141,10 +141,9 @@ int nft_register_basechain(struct nft_base_chain *basechain,
 
 	return nf_register_net_hooks(net, basechain->ops, hook_nops);
 }
-EXPORT_SYMBOL_GPL(nft_register_basechain);
 
-void nft_unregister_basechain(struct nft_base_chain *basechain,
-			      unsigned int hook_nops)
+static void nft_unregister_basechain(struct nft_base_chain *basechain,
+				     unsigned int hook_nops)
 {
 	struct net *net = read_pnet(&basechain->pnet);
 
@@ -153,7 +152,6 @@ void nft_unregister_basechain(struct nft_base_chain *basechain,
 
 	nf_unregister_net_hooks(net, basechain->ops, hook_nops);
 }
-EXPORT_SYMBOL_GPL(nft_unregister_basechain);
 
 static int nf_tables_register_hooks(const struct nft_table *table,
 				    struct nft_chain *chain,
@@ -4590,6 +4588,27 @@ static int __net_init nf_tables_init_net(struct net *net)
 	return 0;
 }
 
+int __nft_release_basechain(struct nft_ctx *ctx)
+{
+	struct nft_rule *rule, *nr;
+
+	BUG_ON(!(ctx->chain->flags & NFT_BASE_CHAIN));
+
+	nf_tables_unregister_hooks(ctx->chain->table, ctx->chain,
+				   ctx->afi->nops);
+	list_for_each_entry_safe(rule, nr, &ctx->chain->rules, list) {
+		list_del(&rule->list);
+		ctx->chain->use--;
+		nf_tables_rule_destroy(ctx, rule);
+	}
+	list_del(&ctx->chain->list);
+	ctx->table->use--;
+	nf_tables_chain_destroy(ctx->chain);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__nft_release_basechain);
+
 /* Called by nft_unregister_afinfo() from __net_exit path, nfnl_lock is held. */
 static void __nft_release_afinfo(struct net *net, struct nft_af_info *afi)
 {

net/netfilter/nf_tables_netdev.c

@@ -156,35 +156,17 @@ static const struct nf_chain_type nft_filter_chain_netdev = {
 	.hook_mask	= (1 << NF_NETDEV_INGRESS),
 };
 
-static void nft_netdev_event(unsigned long event, struct nft_af_info *afi,
-			     struct net_device *dev, struct nft_table *table,
-			     struct nft_base_chain *basechain)
+static void nft_netdev_event(unsigned long event, struct net_device *dev,
+			     struct nft_ctx *ctx)
 {
-	switch (event) {
-	case NETDEV_REGISTER:
-		if (strcmp(basechain->dev_name, dev->name) != 0)
-			return;
+	struct nft_base_chain *basechain = nft_base_chain(ctx->chain);
 
-		BUG_ON(!(basechain->flags & NFT_BASECHAIN_DISABLED));
-
-		dev_hold(dev);
-		basechain->ops[0].dev = dev;
-		basechain->flags &= ~NFT_BASECHAIN_DISABLED;
-		if (!(table->flags & NFT_TABLE_F_DORMANT))
-			nft_register_basechain(basechain, afi->nops);
-		break;
+	switch (event) {
 	case NETDEV_UNREGISTER:
 		if (strcmp(basechain->dev_name, dev->name) != 0)
 			return;
 
-		BUG_ON(basechain->flags & NFT_BASECHAIN_DISABLED);
-
-		if (!(table->flags & NFT_TABLE_F_DORMANT))
-			nft_unregister_basechain(basechain, afi->nops);
-
-		dev_put(basechain->ops[0].dev);
-		basechain->ops[0].dev = NULL;
-		basechain->flags |= NFT_BASECHAIN_DISABLED;
+		__nft_release_basechain(ctx);
 		break;
 	case NETDEV_CHANGENAME:
 		if (dev->ifindex != basechain->ops[0].dev->ifindex)
@@ -201,20 +183,29 @@ static int nf_tables_netdev_event(struct notifier_block *this,
 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 	struct nft_af_info *afi;
 	struct nft_table *table;
-	struct nft_chain *chain;
+	struct nft_chain *chain, *nr;
+	struct nft_ctx ctx = {
+		.net	= dev_net(dev),
+	};
+
+	if (event != NETDEV_UNREGISTER &&
+	    event != NETDEV_CHANGENAME)
+		return NOTIFY_DONE;
 
 	nfnl_lock(NFNL_SUBSYS_NFTABLES);
 	list_for_each_entry(afi, &dev_net(dev)->nft.af_info, list) {
+		ctx.afi = afi;
 		if (afi->family != NFPROTO_NETDEV)
 			continue;
 
 		list_for_each_entry(table, &afi->tables, list) {
-			list_for_each_entry(chain, &table->chains, list) {
+			ctx.table = table;
+			list_for_each_entry_safe(chain, nr, &table->chains, list) {
 				if (!(chain->flags & NFT_BASE_CHAIN))
 					continue;
 
-				nft_netdev_event(event, afi, dev, table,
-						 nft_base_chain(chain));
+				ctx.chain = chain;
+				nft_netdev_event(event, dev, &ctx);
 			}
 		}
 	}