Patch "netfilter: iptables: Fix potential null-ptr-deref in ip6table_nat_table_init()." has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    netfilter: iptables: Fix potential null-ptr-deref in ip6table_nat_table_init().

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     netfilter-iptables-fix-potential-null-ptr-deref-in-i.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit b6631a12be88c7dea2228946abab87528cc77521
Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Date:   Thu Jul 25 12:28:21 2024 -0700

    netfilter: iptables: Fix potential null-ptr-deref in ip6table_nat_table_init().
    
    [ Upstream commit c22921df777de5606f1047b1345b8d22ef1c0b34 ]
    
    ip6table_nat_table_init() accesses net->gen->ptr[ip6table_nat_net_ops.id],
    but the function is exposed to user space before the entry is allocated
    via register_pernet_subsys().
    
    Let's call register_pernet_subsys() before xt_register_template().
    
    Fixes: fdacd57c79b7 ("netfilter: x_tables: never register tables by default")
    Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
    Reviewed-by: Florian Westphal <fw@xxxxxxxxx>
    Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/ipv6/netfilter/ip6table_nat.c b/net/ipv6/netfilter/ip6table_nat.c
index bf3cb3a13600c..52d597b16b658 100644
--- a/net/ipv6/netfilter/ip6table_nat.c
+++ b/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);