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().
BUG=b/361043348
TEST=presubmit
RELEASE_NOTE=Fixes CVE-2024-42269 in the Linux kernel
cos-patch: security-moderate
Fixes: fdacd57c79b7 ("netfilter: x_tables: never register tables by default")
Change-Id: I8b314a00e166cf0fa0b892fcf19fb9bddb0bdd7b
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Arnav Kansal <rnv@google.com>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/79225
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Oleksandr Tymoshenko <ovt@google.com>
Reviewed-by: Kevin Berry <kpberry@google.com>
diff --git a/net/ipv6/netfilter/ip6table_nat.c b/net/ipv6/netfilter/ip6table_nat.c
index bf3cb3a..52d597b 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);
