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From:   Sasha Levin <Alexander.Levin@microsoft.com>
To:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>
CC:     linzhang <xiaolou4617@gmail.com>,
        "David S . Miller" <davem@davemloft.net>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL for 4.4 046/167] net: x25: fix one potential
 use-after-free issue
Thread-Topic: [PATCH AUTOSEL for 4.4 046/167] net: x25: fix one potential
 use-after-free issue
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Date:   Mon, 19 Mar 2018 16:06:18 +0000
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From: linzhang <xiaolou4617@gmail.com>

[ Upstream commit 64df6d525fcff1630098db9238bfd2b3e092d5c1 ]

The function x25_init is not properly unregister related resources
on error handler.It is will result in kernel oops if x25_init init
failed, so add properly unregister call on error handler.

Also, i adjust the coding style and make x25_register_sysctl properly
return failure.

Signed-off-by: linzhang <xiaolou4617@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 include/net/x25.h        |  4 ++--
 net/x25/af_x25.c         | 24 ++++++++++++++++--------
 net/x25/sysctl_net_x25.c |  5 ++++-
 3 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/include/net/x25.h b/include/net/x25.h
index c383aa4edbf0..6d30a01d281d 100644
--- a/include/net/x25.h
+++ b/include/net/x25.h
@@ -298,10 +298,10 @@ void x25_check_rbuf(struct sock *);
=20
 /* sysctl_net_x25.c */
 #ifdef CONFIG_SYSCTL
-void x25_register_sysctl(void);
+int x25_register_sysctl(void);
 void x25_unregister_sysctl(void);
 #else
-static inline void x25_register_sysctl(void) {};
+static inline int x25_register_sysctl(void) { return 0; };
 static inline void x25_unregister_sysctl(void) {};
 #endif /* CONFIG_SYSCTL */
=20
diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c
index a750f330b8dd..c6ab4da4b8e2 100644
--- a/net/x25/af_x25.c
+++ b/net/x25/af_x25.c
@@ -1794,32 +1794,40 @@ void x25_kill_by_neigh(struct x25_neigh *nb)
=20
 static int __init x25_init(void)
 {
-	int rc =3D proto_register(&x25_proto, 0);
+	int rc;
=20
-	if (rc !=3D 0)
+	rc =3D proto_register(&x25_proto, 0);
+	if (rc)
 		goto out;
=20
 	rc =3D sock_register(&x25_family_ops);
-	if (rc !=3D 0)
+	if (rc)
 		goto out_proto;
=20
 	dev_add_pack(&x25_packet_type);
=20
 	rc =3D register_netdevice_notifier(&x25_dev_notifier);
-	if (rc !=3D 0)
+	if (rc)
 		goto out_sock;
=20
-	pr_info("Linux Version 0.2\n");
+	rc =3D x25_register_sysctl();
+	if (rc)
+		goto out_dev;
=20
-	x25_register_sysctl();
 	rc =3D x25_proc_init();
-	if (rc !=3D 0)
-		goto out_dev;
+	if (rc)
+		goto out_sysctl;
+
+	pr_info("Linux Version 0.2\n");
+
 out:
 	return rc;
+out_sysctl:
+	x25_unregister_sysctl();
 out_dev:
 	unregister_netdevice_notifier(&x25_dev_notifier);
 out_sock:
+	dev_remove_pack(&x25_packet_type);
 	sock_unregister(AF_X25);
 out_proto:
 	proto_unregister(&x25_proto);
diff --git a/net/x25/sysctl_net_x25.c b/net/x25/sysctl_net_x25.c
index 43239527a205..703d46aae7a2 100644
--- a/net/x25/sysctl_net_x25.c
+++ b/net/x25/sysctl_net_x25.c
@@ -73,9 +73,12 @@ static struct ctl_table x25_table[] =3D {
 	{ 0, },
 };
=20
-void __init x25_register_sysctl(void)
+int __init x25_register_sysctl(void)
 {
 	x25_table_header =3D register_net_sysctl(&init_net, "net/x25", x25_table)=
;
+	if (!x25_table_header)
+		return -ENOMEM;
+	return 0;
 }
=20
 void x25_unregister_sysctl(void)
--=20
2.14.1