[PATCH 4.4 01/59] media: imon: Fix null-ptr-deref in imon_probe

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Arvind Yadav <arvind.yadav.cs@xxxxxxxxx>

commit 58fd55e838276a0c13d1dc7c387f90f25063cbf3 upstream.

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@xxxxxxxxx>
Tested-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Signed-off-by: Sean Young <sean@xxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxx>
Cc: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/media/rc/imon.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/media/rc/imon.c
+++ b/drivers/media/rc/imon.c
@@ -2419,6 +2419,11 @@ 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) {