2017-04-22 10:15:23

by Malcolm Priestley

Subject: [PATCH 1/2] staging: vt6656: use off stack for out buffer USB transfers.

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 <[email protected]>
Cc: <[email protected]> # v4.9+
---
drivers/staging/vt6656/usbpipe.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/vt6656/usbpipe.c b/drivers/staging/vt6656/usbpipe.c
index 9ad8503d2589..ea5a7c65ad1b 100644
--- a/drivers/staging/vt6656/usbpipe.c
+++ b/drivers/staging/vt6656/usbpipe.c
@@ -47,15 +47,25 @@ int vnt_control_out(struct vnt_private *priv, u8 request, u16 value,
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);

--
2.11.0

2017-04-28 10:02:05

by Greg Kroah-Hartman

Subject: Re: [PATCH 1/2] staging: vt6656: use off stack for out buffer USB transfers.

On Sat, Apr 22, 2017 at 11:14:57AM +0100, Malcolm Priestley wrote:
> Since 4.9 mandated USB buffers be heap allocated this causes the driver
> to fail.

It's really been a requirement since the 2.2 days, it's just that not
many people ran USB drivers on the platforms that required it :)

thanks,

greg k-h

2017-04-22 10:15:24

by Malcolm Priestley

Subject: [PATCH 2/2] 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 <[email protected]>
Cc: <[email protected]> # v4.9+
---
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);

--
2.11.0