USB: gadget: Read buffer overflow

Check whether index is within bounds before testing the element.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/composite.c

@@ -602,7 +602,7 @@ static int get_string(struct usb_composite_dev *cdev,
 			}
 		}
 
-		for (len = 0; s->wData[len] && len <= 126; len++)
+		for (len = 0; len <= 126 && s->wData[len]; len++)
 			continue;
 		if (!len)
 			return -EINVAL;