[PATCH v1 nf 2/2] netfilter: iptables: Fix potential null-ptr-deref in ip6table_nat_table_init().
From: Kuniyuki Iwashima <hidden>
Date: 2024-07-25 19:29:27
Also in:
netfilter-devel
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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 <redacted>
---
net/ipv6/netfilter/ip6table_nat.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/net/ipv6/netfilter/ip6table_nat.c b/net/ipv6/netfilter/ip6table_nat.c
index 52cf104e3478..e119d4f090cc 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);
--
2.30.2