Re: [PATCH 4.4 63/99] [media] usbvision fix overflow of interfaces array

Holger Hoffstätte
2016-06-05T22:30:15Z

On Sun, 05 Jun 2016 14:41:36 -0700, Greg Kroah-Hartman wrote:

> 4.4-stable review patch. If anyone has any objections, please let me know.
>
> ------------------
>
> From: Oliver Neukum <oneukum@suse.com>
>
> 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@suse.com>
> Cc: Vladis Dronov <vdronov@redhat.com>
> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
> Cc: Moritz Muehlenhoff <moritz@wikimedia.org>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>
> ---
> drivers/media/usb/usbvision/usbvision-video.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> --- a/drivers/media/usb/usbvision/usbvision-video.c
> +++ b/drivers/media/usb/usbvision/usbvision-video.c
> @@ -1461,6 +1461,13 @@ static int usbvision_probe(struct usb_in
> 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 if (ifnum < dev->actconfig->desc.bNumInterfaces)

Not sure if it matters, but heads up anyway that for some reason this
patch is a duplicate and was previously applied quite some time ago:

https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/commit/?h=linux-4.4.y&id=588afcc1c0e45358159090d95bf7b246fb67565f

-h