From: Arvind Yadav <arvind.yadav.cs@gmail.com>
Date: Mon, 9 Oct 2017 20:14:48 +0200
Subject: media: imon: Fix null-ptr-deref in imon_probe
Origin: https://git.kernel.org/linus/58fd55e838276a0c13d1dc7c387f90f25063cbf3
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2017-16537

It seems that the return value of usb_ifnum_to_if() can be NULL and
needs to be checked.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
---
 drivers/media/rc/imon.c | 5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/media/rc/imon.c
+++ b/drivers/media/rc/imon.c
@@ -2516,6 +2516,11 @@ static int imon_probe(struct usb_interfa
 	mutex_lock(&driver_lock);
 
 	first_if = usb_ifnum_to_if(usbdev, 0);
+	if (!first_if) {
+		ret = -ENODEV;
+		goto fail;
+	}
+
 	first_if_ctx = usb_get_intfdata(first_if);
 
 	if (ifnum == 0) {