[PATCH 4.4 10/56] staging: vt6656: use off stack for out buffer USB transfers.

[Greg Kroah-Hartman]

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

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

From: Malcolm Priestley <tvboxspy@xxxxxxxxx>

commit 12ecd24ef93277e4e5feaf27b0b18f2d3828bc5e upstream.

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

Since there is a wide range of buffer sizes use kmemdup to create
allocated buffer.

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

---
 drivers/staging/vt6656/usbpipe.c |   14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

--- a/drivers/staging/vt6656/usbpipe.c
+++ b/drivers/staging/vt6656/usbpipe.c
@@ -50,15 +50,25 @@ int vnt_control_out(struct vnt_private *
 		u16 index, u16 length, u8 *buffer)
 {
 	int status = 0;
+	u8 *usb_buffer;
 
 	if (test_bit(DEVICE_FLAGS_DISCONNECTED, &priv->flags))
 		return STATUS_FAILURE;
 
 	mutex_lock(&priv->usb_lock);
 
+	usb_buffer = kmemdup(buffer, length, GFP_KERNEL);
+	if (!usb_buffer) {
+		mutex_unlock(&priv->usb_lock);
+		return -ENOMEM;
+	}
+
 	status = usb_control_msg(priv->usb,
-		usb_sndctrlpipe(priv->usb, 0), request, 0x40, value,
-			index, buffer, length, USB_CTL_WAIT);
+				 usb_sndctrlpipe(priv->usb, 0),
+				 request, 0x40, value,
+				 index, usb_buffer, length, USB_CTL_WAIT);
+
+	kfree(usb_buffer);
 
 	mutex_unlock(&priv->usb_lock);