usb: misc: iowarrior: fix information leak to userland

Structure iowarrior_info is copied to userland with padding byted
between "serial" and "revision" fields uninitialized.  It leads to
leaking of contents of kernel stack memory.
Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
Cc: stable <stable@kernel.org>
Acked-by: Kees Cook <kees.cook@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/misc/iowarrior.c

@@ -553,6 +553,7 @@ static long iowarrior_ioctl(struct file *file, unsigned int cmd,
 			/* needed for power consumption */
 			struct usb_config_descriptor *cfg_descriptor = &dev->udev->actconfig->desc;
 
+			memset(&info, 0, sizeof(info));
 			/* directly from the descriptor */
 			info.vendor = le16_to_cpu(dev->udev->descriptor.idVendor);
 			info.product = dev->product_id;