netdev - [PATCH net-next 20/26] netfilter: nf_tables: Respect NETDEV

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Message-Id: <20250522165238.378456-21-pablo@netfilter.org>
Date: Thu, 22 May 2025 18:52:32 +0200
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net,
	netdev@...r.kernel.org,
	kuba@...nel.org,
	pabeni@...hat.com,
	edumazet@...gle.com,
	fw@...len.de,
	horms@...nel.org
Subject: [PATCH net-next 20/26] netfilter: nf_tables: Respect NETDEV_REGISTER events

From: Phil Sutter <phil@....cc>

Hook into new devices if their name matches the hook spec.

Signed-off-by: Phil Sutter <phil@....cc>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
 net/netfilter/nf_tables_api.c    | 37 +++++++++++++++++++++++++++-----
 net/netfilter/nft_chain_filter.c | 32 +++++++++++++++++++++++----
 2 files changed, 60 insertions(+), 9 deletions(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 95b43499f551..f0f40aeccc0c 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -9689,8 +9689,8 @@ struct nf_hook_ops *nft_hook_find_ops_rcu(const struct nft_hook *hook,
 }
 EXPORT_SYMBOL_GPL(nft_hook_find_ops_rcu);
 
-static void nft_flowtable_event(unsigned long event, struct net_device *dev,
-				struct nft_flowtable *flowtable)
+static int nft_flowtable_event(unsigned long event, struct net_device *dev,
+			       struct nft_flowtable *flowtable)
 {
 	struct nf_hook_ops *ops;
 	struct nft_hook *hook;
@@ -9708,9 +9708,32 @@ static void nft_flowtable_event(unsigned long event, struct net_device *dev,
 			list_del_rcu(&ops->list);
 			kfree_rcu(ops, rcu);
 			break;
+		case NETDEV_REGISTER:
+			if (strcmp(hook->ifname, dev->name))
+				continue;
+
+			ops = kzalloc(sizeof(struct nf_hook_ops),
+				      GFP_KERNEL_ACCOUNT);
+			if (!ops)
+				return 1;
+
+			ops->pf		= NFPROTO_NETDEV;
+			ops->hooknum	= flowtable->hooknum;
+			ops->priority	= flowtable->data.priority;
+			ops->priv	= &flowtable->data;
+			ops->hook	= flowtable->data.type->hook;
+			ops->dev	= dev;
+			if (nft_register_flowtable_ops(dev_net(dev),
+						       flowtable, ops)) {
+				kfree(ops);
+				return 1;
+			}
+			list_add_tail_rcu(&ops->list, &hook->ops_list);
+			break;
 		}
 		break;
 	}
+	return 0;
 }
 
 static int nf_tables_flowtable_event(struct notifier_block *this,
@@ -9722,15 +9745,19 @@ static int nf_tables_flowtable_event(struct notifier_block *this,
 	struct nft_table *table;
 	struct net *net;
 
-	if (event != NETDEV_UNREGISTER)
-		return 0;
+	if (event != NETDEV_REGISTER &&
+	    event != NETDEV_UNREGISTER)
+		return NOTIFY_DONE;
 
 	net = dev_net(dev);
 	nft_net = nft_pernet(net);
 	mutex_lock(&nft_net->commit_mutex);
 	list_for_each_entry(table, &nft_net->tables, list) {
 		list_for_each_entry(flowtable, &table->flowtables, list) {
-			nft_flowtable_event(event, dev, flowtable);
+			if (nft_flowtable_event(event, dev, flowtable)) {
+				mutex_unlock(&nft_net->commit_mutex);
+				return NOTIFY_BAD;
+			}
 		}
 	}
 	mutex_unlock(&nft_net->commit_mutex);
diff --git a/net/netfilter/nft_chain_filter.c b/net/netfilter/nft_chain_filter.c
index 2eee78b58123..58000b3893eb 100644
--- a/net/netfilter/nft_chain_filter.c
+++ b/net/netfilter/nft_chain_filter.c
@@ -318,8 +318,8 @@ static const struct nft_chain_type nft_chain_filter_netdev = {
 	},
 };
 
-static void nft_netdev_event(unsigned long event, struct net_device *dev,
-			     struct nft_base_chain *basechain)
+static int nft_netdev_event(unsigned long event, struct net_device *dev,
+			    struct nft_base_chain *basechain)
 {
 	struct nft_table *table = basechain->chain.table;
 	struct nf_hook_ops *ops;
@@ -338,9 +338,29 @@ static void nft_netdev_event(unsigned long event, struct net_device *dev,
 			list_del_rcu(&ops->list);
 			kfree_rcu(ops, rcu);
 			break;
+		case NETDEV_REGISTER:
+			if (strcmp(hook->ifname, dev->name))
+				continue;
+
+			ops = kmemdup(&basechain->ops,
+				      sizeof(struct nf_hook_ops),
+				      GFP_KERNEL_ACCOUNT);
+			if (!ops)
+				return 1;
+
+			ops->dev = dev;
+
+			if (!(table->flags & NFT_TABLE_F_DORMANT) &&
+			    nf_register_net_hook(dev_net(dev), ops)) {
+				kfree(ops);
+				return 1;
+			}
+			list_add_tail_rcu(&ops->list, &hook->ops_list);
+			break;
 		}
 		break;
 	}
+	return 0;
 }
 
 static int nf_tables_netdev_event(struct notifier_block *this,
@@ -352,7 +372,8 @@ static int nf_tables_netdev_event(struct notifier_block *this,
 	struct nft_chain *chain;
 	struct nft_table *table;
 
-	if (event != NETDEV_UNREGISTER)
+	if (event != NETDEV_REGISTER &&
+	    event != NETDEV_UNREGISTER)
 		return NOTIFY_DONE;
 
 	nft_net = nft_pernet(dev_net(dev));
@@ -371,7 +392,10 @@ static int nf_tables_netdev_event(struct notifier_block *this,
 			    basechain->ops.hooknum != NF_INET_INGRESS)
 				continue;
 
-			nft_netdev_event(event, dev, basechain);
+			if (nft_netdev_event(event, dev, basechain)) {
+				mutex_unlock(&nft_net->commit_mutex);
+				return NOTIFY_BAD;
+			}
 		}
 	}
 	mutex_unlock(&nft_net->commit_mutex);
-- 
2.30.2