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From: Colin King <colin.king@canonical.com>
To: Oliver Hartkopp <socketcan@hartkopp.net>,
	Marc Kleine-Budde <mkl@pengutronix.de>,
	"David S . Miller" <davem@davemloft.net>,
	linux-can@vger.kernel.org, netdev@vger.kernel.org
Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] can: check for null sk before deferencing it via the call to sock_net
Date: Fri,  8 Sep 2017 16:02:35 +0100	[thread overview]
Message-ID: <20170908150235.2931-1-colin.king@canonical.com> (raw)

From: Colin Ian King <colin.king@canonical.com>

The assignment of net via call sock_net will dereference sk. This
is performed before a sanity null check on sk, so there could be
a potential null dereference on the sock_net call if sk is null.
Fix this by assigning net after the sk null check. Also replace
the sk == NULL with the more usual !sk idiom.

Detected by CoverityScan CID#1431862 ("Dereference before null check")

Fixes: 384317ef4187 ("can: network namespace support for CAN_BCM protocol")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 net/can/bcm.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/can/bcm.c b/net/can/bcm.c
index 47a8748d953a..a3791674b8ce 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -1493,13 +1493,14 @@ static int bcm_init(struct sock *sk)
 static int bcm_release(struct socket *sock)
 {
 	struct sock *sk = sock->sk;
-	struct net *net = sock_net(sk);
+	struct net *net;
 	struct bcm_sock *bo;
 	struct bcm_op *op, *next;
 
-	if (sk == NULL)
+	if (!sk)
 		return 0;
 
+	net = sock_net(sk);
 	bo = bcm_sk(sk);
 
 	/* remove bcm_ops, timer, rx_unregister(), etc. */
-- 
2.14.1

WARNING: multiple messages have this Message-ID (diff)
From: Colin King <colin.king@canonical.com>
To: Oliver Hartkopp <socketcan@hartkopp.net>,
	Marc Kleine-Budde <mkl@pengutronix.de>,
	"David S . Miller" <davem@davemloft.net>,
	linux-can@vger.kernel.org, netdev@vger.kernel.org
Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] can: check for null sk before deferencing it via the call to sock_net
Date: Fri, 08 Sep 2017 15:02:35 +0000	[thread overview]
Message-ID: <20170908150235.2931-1-colin.king@canonical.com> (raw)

From: Colin Ian King <colin.king@canonical.com>

The assignment of net via call sock_net will dereference sk. This
is performed before a sanity null check on sk, so there could be
a potential null dereference on the sock_net call if sk is null.
Fix this by assigning net after the sk null check. Also replace
the sk = NULL with the more usual !sk idiom.

Detected by CoverityScan CID#1431862 ("Dereference before null check")

Fixes: 384317ef4187 ("can: network namespace support for CAN_BCM protocol")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 net/can/bcm.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/can/bcm.c b/net/can/bcm.c
index 47a8748d953a..a3791674b8ce 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -1493,13 +1493,14 @@ static int bcm_init(struct sock *sk)
 static int bcm_release(struct socket *sock)
 {
 	struct sock *sk = sock->sk;
-	struct net *net = sock_net(sk);
+	struct net *net;
 	struct bcm_sock *bo;
 	struct bcm_op *op, *next;
 
-	if (sk = NULL)
+	if (!sk)
 		return 0;
 
+	net = sock_net(sk);
 	bo = bcm_sk(sk);
 
 	/* remove bcm_ops, timer, rx_unregister(), etc. */
-- 
2.14.1


             reply	other threads:[~2017-09-08 15:02 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-08 15:02 Colin King [this message]
2017-09-08 15:02 ` [PATCH] can: check for null sk before deferencing it via the call to sock_net Colin King
2017-09-08 17:46 ` Oliver Hartkopp
2017-09-08 17:46   ` Oliver Hartkopp
     [not found]   ` <CABATaM548q4dghmPgrh9qd7+q9Nq1UgA+ESXOrW+45gBWxdq3w@mail.gmail.com>
2017-10-11 10:35     ` Oliver Hartkopp
2017-10-16 16:37   ` Josh Boyer
2017-10-16 16:37     ` Josh Boyer
2017-10-16 17:32     ` Oliver Hartkopp
2017-10-16 17:32       ` Oliver Hartkopp
2017-10-17  5:49 ` Marc Kleine-Budde
2017-10-17  5:49   ` Marc Kleine-Budde

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