netfilter: nf_tables: hold mutex on netns pre_exit path

[ 3923b1e4406680d57da7e873da77b1683035d83f ]

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: Sasha Levin <sashal@kernel.org>

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index e4eef4947cc7570f6a86e53506b81d948bce4965..909076ef157e8ee826f7e04486a388b3648342c8 100644 (file)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -7866,7 +7866,9 @@ static int __net_init nf_tables_init_net(struct net *net)
 
 static void __net_exit nf_tables_pre_exit_net(struct net *net)
 {
+       mutex_lock(&net->nft.commit_mutex);
        __nft_release_hooks(net);
+       mutex_unlock(&net->nft.commit_mutex);
 }
 
 static void __net_exit nf_tables_exit_net(struct net *net)