patch "staging: vt6656: use off stack for in buffer USB transfers." added to staging-testing

patch "staging: vt6656: use off stack for in buffer USB transfers." added to staging-testing

[gregkh]

This is a note to let you know that I've just added the patch titled

    staging: vt6656: use off stack for in buffer USB transfers.

to my staging git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-testing branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will be merged to the staging-next branch sometime soon,
after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.


>From 05c0cf88bec588a7cb34de569acd871ceef26760 Mon Sep 17 00:00:00 2001
From: Malcolm Priestley <tvboxspy@gmail.com>
Date: Sat, 22 Apr 2017 11:14:58 +0100
Subject: staging: vt6656: use off stack for in buffer USB transfers.

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@gmail.com>
Cc: <stable@vger.kernel.org> # v4.9+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/staging/vt6656/usbpipe.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/vt6656/usbpipe.c b/drivers/staging/vt6656/usbpipe.c
index ea5a7c65ad1b..dc11a05be8c4 100644
--- a/drivers/staging/vt6656/usbpipe.c
+++ b/drivers/staging/vt6656/usbpipe.c
@@ -85,15 +85,28 @@ int vnt_control_in(struct vnt_private *priv, u8 request, u16 value,
 		    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);
 
-- 
2.12.2