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

[Greg KH <greg@kroah.com>]

On Sun, Jun 05, 2016 at 09:53:42PM +0000, Holger Hoffst�tte wrote:
> 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

Yes, thanks, sorry for the confusion, Debian seems confused as well as
this is in their kernel tree too...

now dropped, thanks.

greg k-h