From: Oliver Hartkopp <socketcan@hartkopp.net>
Date: Tue, 21 Jun 2016 10:14:07 +0000 (+0200)
Subject: can: fix handling of unmodifiable configuration options fix
X-Git-Tag: v4.6.6~23
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=171cf1dc83ea6ba43038a86ea455c04aee908282;p=thirdparty%2Fkernel%2Fstable.git

can: fix handling of unmodifiable configuration options fix

commit bce271f255dae8335dc4d2ee2c4531e09cc67f5a upstream.

With upstream commit bb208f144cf3f59 (can: fix handling of unmodifiable
configuration options) a new can_validate() function was introduced.

When invoking 'ip link set can0 type can' without any configuration data
can_validate() tries to validate the content without taking into account that
there's totally no content. This patch adds a check for missing content.

Reported-by: ajneu <ajneu1@gmail.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
index 910c12e2638e3..348dd5001fa48 100644
--- a/drivers/net/can/dev.c
+++ b/drivers/net/can/dev.c
@@ -798,6 +798,9 @@ static int can_validate(struct nlattr *tb[], struct nlattr *data[])
 	 * - control mode with CAN_CTRLMODE_FD set
 	 */
 
+	if (!data)
+		return 0;
+
 	if (data[IFLA_CAN_CTRLMODE]) {
 		struct can_ctrlmode *cm = nla_data(data[IFLA_CAN_CTRLMODE]);