[PATCH 5.17 23/75] netfilter: nf_tables: hold mutex on netns pre_exit path

[Greg Kroah-Hartman]

From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 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
@@ -9813,7 +9813,11 @@ 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)