netfilter: nf_tables: GC transaction race with netns dismantle

[ Upstream commit 02c6c24402bf1c1e986899c14ba22a10b510916b ]

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>

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index dcf3ed3d5af9df44fa5fc26451c36068b4e80919..b280b151a9e98dd973abc04ccb16e374f9ff97fa 100644 (file)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -9495,9 +9495,14 @@ 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;