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

[Johan Hovold]

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@xxxxxxxxxxxxxxx>     # 2.6.30
Cc: Sri Deevi <Srinivasa.Deevi@xxxxxxxxxxxx>
Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
 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 e0daa9b6c2a0..9b742d569fb5 100644
--- a/drivers/media/usb/cx231xx/cx231xx-cards.c
+++ b/drivers/media/usb/cx231xx/cx231xx-cards.c
@@ -1684,7 +1684,7 @@ 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) {
 		dev_err(d, "Not found matching IAD interface\n");
 		retval = -ENODEV;
 		goto err_if;
-- 
2.14.1