usbvision: fix crash on detecting device with invalid configuration

commit fa52bd506f274b7619955917abfde355e3d19ffe upstream.

The usbvision driver crashes when a specially crafted usb device with invalid
number of interfaces or endpoints is detected. This fix adds checks that the
device has proper configuration expected by the driver.

Reported-by: Ralf Spenneberg <ralf@spenneberg.net>
Signed-off-by: Vladis Dronov <vdronov@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[bwh: Backport to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/media/video/usbvision/usbvision-video.c b/drivers/media/video/usbvision/usbvision-video.c
index 20787d6..902140e 100644 (file)
--- a/drivers/media/video/usbvision/usbvision-video.c
+++ b/drivers/media/video/usbvision/usbvision-video.c
@@ -1511,9 +1511,23 @@ static int __devinit usbvision_probe(struct usb_interface *intf,
 
        if (usbvision_device_data[model].interface >= 0)
                interface = &dev->actconfig->interface[usbvision_device_data[model].interface]->altsetting[0];
-       else
+       else if (ifnum < dev->actconfig->desc.bNumInterfaces)
                interface = &dev->actconfig->interface[ifnum]->altsetting[0];
+       else {
+               dev_err(&intf->dev, "interface %d is invalid, max is %d\n",
+                   ifnum, dev->actconfig->desc.bNumInterfaces - 1);
+               ret = -ENODEV;
+               goto err_usb;
+       }
+
+       if (interface->desc.bNumEndpoints < 2) {
+               dev_err(&intf->dev, "interface %d has %d endpoints, but must"
+                   " have minimum 2\n", ifnum, interface->desc.bNumEndpoints);
+               ret = -ENODEV;
+               goto err_usb;
+       }
        endpoint = &interface->endpoint[1].desc;
+
        if (!usb_endpoint_xfer_isoc(endpoint)) {
                dev_err(&intf->dev, "%s: interface %d. has non-ISO endpoint!\n",
                    __func__, ifnum);