The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 3923b1e4406680d57da7e873da77b1683035d83f Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso pablo@netfilter.org Date: Mon, 30 May 2022 18:24:05 +0200 Subject: [PATCH] netfilter: nf_tables: hold mutex on netns pre_exit path

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

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index dcefb5f36b3a..f77414e13de1 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -9896,7 +9896,11 @@ static int __net_init nf_tables_init_net(struct net *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)