[PATCH 3.12 07/58] [media] usbvision fix overflow of interfaces array

From: Jiri Slaby
Date: Wed Mar 16 2016 - 07:15:05 EST


From: Oliver Neukum <oneukum@xxxxxxxx>

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

===============

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>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
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 ea5ec8ed67a7..3cf12da58787 100644
--- a/drivers/media/usb/usbvision/usbvision-video.c
+++ b/drivers/media/usb/usbvision/usbvision-video.c
@@ -1538,6 +1538,13 @@ 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
--
2.7.3