Commit c22921df authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Pablo Neira Ayuso
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netfilter: iptables: Fix potential null-ptr-deref in ip6table_nat_table_init(). 



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: fdacd57c ("netfilter: x_tables: never register tables by default")
Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 5830aa86

net/ipv6/netfilter/ip6table_nat.c

+9 −5
Original line number Diff line number Diff line
@@ -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);