[PATCH 5.15 25/66] netfilter: nf_tables: hold mutex on netns pre_exit path

Greg Kroah-Hartman
2022-06-03T17:58:34Z

From: Pablo Neira Ayuso <pablo@netfilter.org>

commit 3923b1e4406680d57da7e873da77b1683035d83f upstream.

clean_net() runs in workqueue while walking over the lists, grab mutex.

Fixes: 767d1216bff8 ("netfilter: nftables: fix possible UAF over chains from packet path in netns")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/netfilter/nf_tables_api.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -9746,7 +9746,11 @@ static int __net_init nf_tables_init_net

static void __net_exit nf_tables_pre_exit_net(struct net *net)
{
+ struct nftables_pernet *nft_net = nft_pernet(net);
+
+ mutex_lock(&nft_net->commit_mutex);
__nft_release_hooks(net);
+ mutex_unlock(&nft_net->commit_mutex);
}

static void __net_exit nf_tables_exit_net(struct net *net)