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