From cbdd39ce42530a193c56beb206a3356cb6d01016 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Thu, 3 Sep 2026 01:28:56 +0200 Subject: [PATCH] netfilter: nf_nat: unregister and release hooks on error If nf_hook_entries_insert_raw() fails, the NAT hooks get never released, resulting in a memleak. Postpone setting nat_proto_net->nat_hook_ops when the hooks are registered to simplify the error path to decide whether the nat hooks need unwinding. Fixes: 1cd472bf036c ("netfilter: nf_nat: add nat hook register functions to nf_nat") Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_nat_core.c | 46 ++++++++++++++++++++++++------------- 1 file changed, 30 insertions(+), 16 deletions(-) diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c index 8ac326e1eb5b..a4858c2b2d65 100644 --- a/net/netfilter/nf_nat_core.c +++ b/net/netfilter/nf_nat_core.c @@ -1224,31 +1224,45 @@ int nf_nat_register_fn(struct net *net, u8 pf, const struct nf_hook_ops *ops, } ret = nf_register_net_hooks(net, nat_ops, ops_count); - if (ret < 0) { - mutex_unlock(&nf_nat_proto_mutex); - for (i = 0; i < ops_count; i++) { - priv = nat_ops[i].priv; - kfree_rcu(priv, rcu_head); - } - kfree_rcu(nat_ops, rcu); - return ret; - } - - nat_proto_net->nat_hook_ops = nat_ops; + if (ret < 0) + goto err_free_hooks; + } else { + nat_ops = nat_proto_net->nat_hook_ops; } - nat_ops = nat_proto_net->nat_hook_ops; priv = nat_ops[hooknum].priv; if (WARN_ON_ONCE(!priv)) { - mutex_unlock(&nf_nat_proto_mutex); - return -EOPNOTSUPP; + ret = -EOPNOTSUPP; + goto err_unregister_hooks; } ret = nf_hook_entries_insert_raw(&priv->entries, ops); - if (ret == 0) - nat_proto_net->users++; + if (ret) + goto err_unregister_hooks; + + if (!nat_proto_net->nat_hook_ops) + nat_proto_net->nat_hook_ops = nat_ops; + + nat_proto_net->users++; mutex_unlock(&nf_nat_proto_mutex); + + return 0; + +err_unregister_hooks: + if (nat_proto_net->nat_hook_ops) { + mutex_unlock(&nf_nat_proto_mutex); + return ret; + } + nf_unregister_net_hooks(net, nat_ops, ops_count); +err_free_hooks: + mutex_unlock(&nf_nat_proto_mutex); + for (i = 0; i < ops_count; i++) { + priv = nat_ops[i].priv; + kfree_rcu(priv, rcu_head); + } + kfree_rcu(nat_ops, rcu); + return ret; }