netdev - [PATCH net-next] openvswitch: use after free in __ovs_ct_free

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Message-ID: <20190402065314.GA14444@kadam>
Date:   Tue, 2 Apr 2019 09:53:14 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Pravin B Shelar <pshelar@....org>,
        Yi-Hung Wei <yihung.wei@...il.com>
Cc:     "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
        dev@...nvswitch.org, kernel-janitors@...r.kernel.org
Subject: [PATCH net-next] openvswitch: use after free in
 __ovs_ct_free_action()

We free "ct_info->ct" and then use it on the next line when we pass it
to nf_ct_destroy_timeout().  This patch swaps the order to avoid the use
after free.

Fixes: 06bd2bdf19d2 ("openvswitch: Add timeout support to ct action")
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
---
 net/openvswitch/conntrack.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
index 121b01d4a3c0..0be3ab5bde26 100644
--- a/net/openvswitch/conntrack.c
+++ b/net/openvswitch/conntrack.c
@@ -1804,9 +1804,9 @@ static void __ovs_ct_free_action(struct ovs_conntrack_info *ct_info)
 	if (ct_info->helper)
 		nf_conntrack_helper_put(ct_info->helper);
 	if (ct_info->ct) {
-		nf_ct_tmpl_free(ct_info->ct);
 		if (ct_info->timeout[0])
 			nf_ct_destroy_timeout(ct_info->ct);
+		nf_ct_tmpl_free(ct_info->ct);
 	}
 }
 
-- 
2.17.1