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

[Holger Hoffstätte]

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@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 <moritz@xxxxxxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> 
> ---
>  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