[PATCH 3.16.y-ckt 001/129] [media] usbvision fix overflow of interfaces array

From: Luis Henriques
Date: Fri Feb 26 2016 - 05:22:03 EST


3.16.7-ckt25 -stable review patch. If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Oliver Neukum <oneukum@xxxxxxxx>

commit 588afcc1c0e45358159090d95bf7b246fb67565f upstream.

This fixes the crash reported in:
http://seclists.org/bugtraq/2015/Oct/35
The interface number needs a sanity check.

Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx>
Cc: Vladis Dronov <vdronov@xxxxxxxxxx>
Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxx>
Cc: Moritz Muehlenhoff <jmm@xxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
drivers/media/usb/usbvision/usbvision-video.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/media/usb/usbvision/usbvision-video.c b/drivers/media/usb/usbvision/usbvision-video.c
index 68bc9615660e..01d0dd99bb24 100644
--- a/drivers/media/usb/usbvision/usbvision-video.c
+++ b/drivers/media/usb/usbvision/usbvision-video.c
@@ -1536,6 +1536,13 @@ static int usbvision_probe(struct usb_interface *intf,
printk(KERN_INFO "%s: %s found\n", __func__,
usbvision_device_data[model].model_string);

+ /*
+ * this is a security check.
+ * an exploit using an incorrect bInterfaceNumber is known
+ */
+ if (ifnum >= USB_MAXINTERFACES || !dev->actconfig->interface[ifnum])
+ return -ENODEV;
+
if (usbvision_device_data[model].interface >= 0)
interface = &dev->actconfig->interface[usbvision_device_data[model].interface]->altsetting[0];
else