netfilter: ctnetlink: fix possible refcount leak in ctnetlink_create_conntrack()

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2189550
Upstream Status: commit ac48939

commit ac48939
Author: Hangyu Hua <hbh25y@gmail.com>
Date:   Fri Feb 10 15:17:30 2023 +0800

    netfilter: ctnetlink: fix possible refcount leak in ctnetlink_create_conntrack()

    nf_ct_put() needs to be called to put the refcount got by
    nf_conntrack_find_get() to avoid refcount leak when
    nf_conntrack_hash_check_insert() fails.

    Fixes: 7d367e0 ("netfilter: ctnetlink: fix soft lockup when netlink adds new entries (v2)")
    Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
    Acked-by: Florian Westphal <fw@strlen.de>
    Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Signed-off-by: Florian Westphal <fwestpha@redhat.com>

Author: fw-strlen

net/netfilter/nf_conntrack_netlink.c

@@ -2380,12 +2380,15 @@ ctnetlink_create_conntrack(struct net *net,
 
 	err = nf_conntrack_hash_check_insert(ct);
 	if (err < 0)
-		goto err2;
+		goto err3;
 
 	rcu_read_unlock();
 
 	return ct;
 
+err3:
+	if (ct->master)
+		nf_ct_put(ct->master);
 err2:
 	rcu_read_unlock();
 err1: