cx231xx-cards: fix NULL-deref on missing association descriptor

commit 6c3b047fa2d2286d5e438bcb470c7b1a49f415f6 upstream.

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")

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>
[bwh: Backported to 3.2: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/media/video/cx231xx/cx231xx-cards.c b/drivers/media/video/cx231xx/cx231xx-cards.c
index 21f23b6..10b8b85 100644 (file)
--- a/drivers/media/video/cx231xx/cx231xx-cards.c
+++ b/drivers/media/video/cx231xx/cx231xx-cards.c
@@ -1127,7 +1127,7 @@ 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;