From bcb74e132a76ce0502bb33d5b65533a4ed72d159 Mon Sep 17 00:00:00 2001
From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Date: Thu, 24 Mar 2022 16:22:10 -0300
Subject: [PATCH] net/sched: act_ct: fix ref leak when switching zones
Git-commit: bcb74e132a76ce0502bb33d5b65533a4ed72d159
Patch-mainline: v5.18-rc1
References: bsc#1207361

When switching zones or network namespaces without doing a ct clear in
between, it is now leaking a reference to the old ct entry. That's
because tcf_ct_skb_nfct_cached() returns false and
tcf_ct_flow_table_lookup() may simply overwrite it.

The fix is to, as the ct entry is not reusable, free it already at
tcf_ct_skb_nfct_cached().

Reported-by: Florian Westphal <fw@strlen.de>
Fixes: 2f131de361f6 ("net/sched: act_ct: Fix flow table lookup after ct clear or switching zones")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Wiesner <jwiesner@suse.de>
---
 net/sched/act_ct.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c
index 6a34f7b80a6d..b1f502fce595 100644
--- a/net/sched/act_ct.c
+++ b/net/sched/act_ct.c
@@ -583,22 +583,25 @@ static bool tcf_ct_skb_nfct_cached(struct net *net, struct sk_buff *skb,
 	if (!ct)
 		return false;
 	if (!net_eq(net, read_pnet(&ct->ct_net)))
-		return false;
+		goto drop_ct;
 	if (nf_ct_zone(ct)->id != zone_id)
-		return false;
+		goto drop_ct;
 
 	/* Force conntrack entry direction. */
 	if (force && CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL) {
 		if (nf_ct_is_confirmed(ct))
 			nf_ct_kill(ct);
 
-		nf_conntrack_put(&ct->ct_general);
-		nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
-
-		return false;
+		goto drop_ct;
 	}
 
 	return true;
+
+drop_ct:
+	nf_conntrack_put(&ct->ct_general);
+	nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
+
+	return false;
 }
 
 /* Trim the skb to the length specified by the IP/IPv6 header,
-- 
2.35.3