From 6c3b047fa2d2286d5e438bcb470c7b1a49f415f6 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Thu, 21 Sep 2017 05:40:18 -0300
Subject: [PATCH] [media] cx231xx-cards: fix NULL-deref on missing association descriptor
Git-commit: 6c3b047fa2d2286d5e438bcb470c7b1a49f415f6
Patch-mainline: v4.15-rc1
References: CVE-2017-16536 bsc#1066606

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@vger.kernel.org>     # 2.6.30
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/media/usb/cx231xx/cx231xx-cards.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/media/usb/cx231xx/cx231xx-cards.c
+++ b/drivers/media/usb/cx231xx/cx231xx-cards.c
@@ -1650,7 +1650,7 @@ static int cx231xx_usb_probe(struct usb_
 	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;