netfilter: nf_tables: hold mutex on netns pre_exit path

Origin: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit?id=8b7454dd984a75d0eaa6a02940c65cd3671fcddc

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>
Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name netfilter-nf_tables-hold-mutex-on-netns-pre_exit-pat.patch

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 8958dda69a6de3173f1667140a5ac115d628e077..9ee9cba61380c83989bbe9bda291eb5b856f1ebb 100644 (file)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -8987,7 +8987,9 @@ 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)