From: Sasha Levin <sashal@kernel.org>
Date: Fri, 22 Sep 2023 17:01:10 +0000 (+0200)
Subject: netfilter: nf_tables: GC transaction race with netns dismantle
X-Git-Tag: archive/raspbian/5.10.197-1+rpi1^2~27
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=1944515f5b440827ec4915d8686616975ea787f2;p=linux.git

netfilter: nf_tables: GC transaction race with netns dismantle

commit 02c6c24402bf1c1e986899c14ba22a10b510916b upstream.

Use maybe_get_net() since GC workqueue might race with netns exit path.

Fixes: 5f68718b34a5 ("netfilter: nf_tables: GC transaction API to avoid race with control plane")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name netfilter-nf_tables-gc-transaction-race-with-netns-d.patch
---

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 43da2f0a526..78bf82f89ec 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -8089,9 +8089,14 @@ struct nft_trans_gc *nft_trans_gc_alloc(struct nft_set *set,
 	if (!trans)
 		return NULL;
 
+	trans->net = maybe_get_net(net);
+	if (!trans->net) {
+		kfree(trans);
+		return NULL;
+	}
+
 	refcount_inc(&set->refs);
 	trans->set = set;
-	trans->net = get_net(net);
 	trans->seq = gc_seq;
 
 	return trans;