USB: gadget: zero allocate endpoint 0 buffers

Under some conditions, USB gadget devices can show allocated buffer
contents to a host.  Fix this up by zero-allocating them so that any
extra data will all just be zeros.
Reported-by: Szymon Heidrich <szymon.heidrich@gmail.com>
Tested-by: Szymon Heidrich <szymon.heidrich@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/composite.c

@@ -2221,7 +2221,7 @@ int composite_dev_prepare(struct usb_composite_driver *composite,
 	if (!cdev->req)
 		return -ENOMEM;
 
-	cdev->req->buf = kmalloc(USB_COMP_EP0_BUFSIZ, GFP_KERNEL);
+	cdev->req->buf = kzalloc(USB_COMP_EP0_BUFSIZ, GFP_KERNEL);
 	if (!cdev->req->buf)
 		goto fail;
 

drivers/usb/gadget/legacy/dbgp.c

@@ -137,7 +137,7 @@ static int dbgp_enable_ep_req(struct usb_ep *ep)
 		goto fail_1;
 	}
 
-	req->buf = kmalloc(DBGP_REQ_LEN, GFP_KERNEL);
+	req->buf = kzalloc(DBGP_REQ_LEN, GFP_KERNEL);
 	if (!req->buf) {
 		err = -ENOMEM;
 		stp = 2;