[PATCH 4.9 11/80] staging: vt6656: use off stack for out buffer USB transfers.

From: Greg Kroah-Hartman
Date: Thu May 18 2017 - 06:58:20 EST


4.9-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
@@ -47,15 +47,25 @@ 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);