[PATCH] [media] cx231xx-cards: fix NULL-deref on missing association descriptor

[Paolo Pisati]

From: Johan Hovold <johan at kernel.org>

Make sure to check that we actually have an Interface Association
Descriptor before dereferencing it during probe to avoid dereferencing a
NULL-pointer.

Fixes: e0d3bafd0258 ("V4L/DVB (10954): Add cx231xx USB driver")

Cc: stable <stable at vger.kernel.org>     # 2.6.30
Reported-by: Andrey Konovalov <andreyknvl at google.com>
Signed-off-by: Johan Hovold <johan at kernel.org>
Tested-by: Andrey Konovalov <andreyknvl at google.com>
Signed-off-by: Hans Verkuil <hans.verkuil at cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab at osg.samsung.com>
(cherry picked from commit 6c3b047fa2d2286d5e438bcb470c7b1a49f415f6)
Signed-off-by: Paolo Pisati <paolo.pisati at canonical.com>
---
 drivers/media/usb/cx231xx/cx231xx-cards.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/usb/cx231xx/cx231xx-cards.c b/drivers/media/usb/cx231xx/cx231xx-cards.c
index 528cce9..09d4fb6 100644
--- a/drivers/media/usb/cx231xx/cx231xx-cards.c
+++ b/drivers/media/usb/cx231xx/cx231xx-cards.c
@@ -1224,7 +1224,7 @@ static int cx231xx_usb_probe(struct usb_interface *interface,
 	nr = dev->devno;
 
 	assoc_desc = udev->actconfig->intf_assoc[0];
-	if (assoc_desc->bFirstInterface != ifnum) {
+	if (!assoc_desc || assoc_desc->bFirstInterface != ifnum) {
 		cx231xx_err(DRIVER_NAME ": Not found "
 			    "matching IAD interface\n");
 		retval = -ENODEV;
-- 
2.7.4