[PATCH 4.9 10/80] staging: vt6656: use off stack for in buffer USB transfers.

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Malcolm Priestley <tvboxspy@xxxxxxxxx>

commit 05c0cf88bec588a7cb34de569acd871ceef26760 upstream.

Since 4.9 mandated USB buffers to be heap allocated. This causes
the driver to fail.

Create buffer for USB transfers.

Signed-off-by: Malcolm Priestley <tvboxspy@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/staging/vt6656/usbpipe.c |   17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

--- a/drivers/staging/vt6656/usbpipe.c
+++ b/drivers/staging/vt6656/usbpipe.c
@@ -75,15 +75,28 @@ int vnt_control_in(struct vnt_private *p
 		u16 index, u16 length, u8 *buffer)
 {
 	int status;
+	u8 *usb_buffer;
 
 	if (test_bit(DEVICE_FLAGS_DISCONNECTED, &priv->flags))
 		return STATUS_FAILURE;
 
 	mutex_lock(&priv->usb_lock);
 
+	usb_buffer = kmalloc(length, GFP_KERNEL);
+	if (!usb_buffer) {
+		mutex_unlock(&priv->usb_lock);
+		return -ENOMEM;
+	}
+
 	status = usb_control_msg(priv->usb,
-		usb_rcvctrlpipe(priv->usb, 0), request, 0xc0, value,
-			index, buffer, length, USB_CTL_WAIT);
+				 usb_rcvctrlpipe(priv->usb, 0),
+				 request, 0xc0, value,
+				 index, usb_buffer, length, USB_CTL_WAIT);
+
+	if (status == length)
+		memcpy(buffer, usb_buffer, length);
+
+	kfree(usb_buffer);
 
 	mutex_unlock(&priv->usb_lock);