Merge tag 'nf-24-07-31' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf

Pablo Neira Ayuso says:

====================
Netfilter fixes for net

The following patchset contains Netfilter fixes for net:

Fix a possible null-ptr-deref sometimes triggered by iptables-restore at
boot time. Register iptables {ipv4,ipv6} nat table pernet in first place
to fix this issue. Patch #1 and #2 from Kuniyuki Iwashima.

netfilter pull request 24-07-31

* tag 'nf-24-07-31' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
  netfilter: iptables: Fix potential null-ptr-deref in ip6table_nat_table_init().
  netfilter: iptables: Fix null-ptr-deref in iptable_nat_table_init().
====================

Link: https://patch.msgid.link/20240731213046.6194-1-pablo@netfilter.orgSigned-off-by: Paolo Abeni <pabeni@redhat.com>

net/ipv4/netfilter/iptable_nat.c

@@ -145,25 +145,27 @@ static struct pernet_operations iptable_nat_net_ops = {
 
 static int __init iptable_nat_init(void)
 {
-	int ret = xt_register_template(&nf_nat_ipv4_table,
-				       iptable_nat_table_init);
+	int ret;
 
+	/* net->gen->ptr[iptable_nat_net_id] must be allocated
+	 * before calling iptable_nat_table_init().
+	 */
+	ret = register_pernet_subsys(&iptable_nat_net_ops);
 	if (ret < 0)
 		return ret;
 
-	ret = register_pernet_subsys(&iptable_nat_net_ops);
-	if (ret < 0) {
-		xt_unregister_template(&nf_nat_ipv4_table);
-		return ret;
-	}
+	ret = xt_register_template(&nf_nat_ipv4_table,
+				   iptable_nat_table_init);
+	if (ret < 0)
+		unregister_pernet_subsys(&iptable_nat_net_ops);
 
 	return ret;
 }
 
 static void __exit iptable_nat_exit(void)
 {
-	unregister_pernet_subsys(&iptable_nat_net_ops);
 	xt_unregister_template(&nf_nat_ipv4_table);
+	unregister_pernet_subsys(&iptable_nat_net_ops);
 }
 
 module_init(iptable_nat_init);

net/ipv6/netfilter/ip6table_nat.c

@@ -147,23 +147,27 @@ static struct pernet_operations ip6table_nat_net_ops = {
 
 static int __init ip6table_nat_init(void)
 {
-	int ret = xt_register_template(&nf_nat_ipv6_table,
-				       ip6table_nat_table_init);
+	int ret;
 
+	/* net->gen->ptr[ip6table_nat_net_id] must be allocated
+	 * before calling ip6t_nat_register_lookups().
+	 */
+	ret = register_pernet_subsys(&ip6table_nat_net_ops);
 	if (ret < 0)
 		return ret;
 
-	ret = register_pernet_subsys(&ip6table_nat_net_ops);
+	ret = xt_register_template(&nf_nat_ipv6_table,
+				   ip6table_nat_table_init);
 	if (ret)
-		xt_unregister_template(&nf_nat_ipv6_table);
+		unregister_pernet_subsys(&ip6table_nat_net_ops);
 
 	return ret;
 }
 
 static void __exit ip6table_nat_exit(void)
 {
-	unregister_pernet_subsys(&ip6table_nat_net_ops);
 	xt_unregister_template(&nf_nat_ipv6_table);
+	unregister_pernet_subsys(&ip6table_nat_net_ops);
 }
 
 module_init(ip6table_nat_init);