[PATCH 2/2] staging: comedi: drivers: usbduxfast.c: fix for DMA buffers on stack

From: Kumar Amit Mehta
Date: Fri Feb 22 2013 - 13:07:48 EST


fix for instances of DMA buffer on stack(being passed to usb_control_msg) for
the USB-DUXfast Board driver.

Signed-off-by: Kumar Amit Mehta <gmate.amit@xxxxxxxxx>
---
drivers/staging/comedi/drivers/usbduxfast.c | 30 ++++++++++++++++-----------
1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/drivers/staging/comedi/drivers/usbduxfast.c b/drivers/staging/comedi/drivers/usbduxfast.c
index 4bf5dd0..1ba0e3d 100644
--- a/drivers/staging/comedi/drivers/usbduxfast.c
+++ b/drivers/staging/comedi/drivers/usbduxfast.c
@@ -436,10 +436,14 @@ static void usbduxfastsub_ai_Irq(struct urb *urb)
static int usbduxfastsub_start(struct usbduxfastsub_s *udfs)
{
int ret;
- unsigned char local_transfer_buffer[16];
+ unsigned char *local_transfer_buffer;
+
+ local_transfer_buffer = kmalloc(1, GFP_KERNEL);
+ if (!local_transfer_buffer)
+ return -ENOMEM;

/* 7f92 to zero */
- local_transfer_buffer[0] = 0;
+ *local_transfer_buffer = 0;
/* bRequest, "Firmware" */
ret = usb_control_msg(udfs->usbdev, usb_sndctrlpipe(udfs->usbdev, 0),
USBDUXFASTSUB_FIRMWARE,
@@ -450,22 +454,25 @@ static int usbduxfastsub_start(struct usbduxfastsub_s *udfs)
local_transfer_buffer,
1, /* Length */
EZTIMEOUT); /* Timeout */
- if (ret < 0) {
+ if (ret < 0)
dev_err(&udfs->interface->dev,
"control msg failed (start)\n");
- return ret;
- }

- return 0;
+ kfree(local_transfer_buffer);
+ return ret;
}

static int usbduxfastsub_stop(struct usbduxfastsub_s *udfs)
{
int ret;
- unsigned char local_transfer_buffer[16];
+ unsigned char *local_transfer_buffer;
+
+ local_transfer_buffer = kmalloc(1, GFP_KERNEL);
+ if (!local_transfer_buffer)
+ return -ENOMEM;

/* 7f92 to one */
- local_transfer_buffer[0] = 1;
+ *local_transfer_buffer = 1;
/* bRequest, "Firmware" */
ret = usb_control_msg(udfs->usbdev, usb_sndctrlpipe(udfs->usbdev, 0),
USBDUXFASTSUB_FIRMWARE,
@@ -474,13 +481,12 @@ static int usbduxfastsub_stop(struct usbduxfastsub_s *udfs)
0x0000, /* Index */
local_transfer_buffer, 1, /* Length */
EZTIMEOUT); /* Timeout */
- if (ret < 0) {
+ if (ret < 0)
dev_err(&udfs->interface->dev,
"control msg failed (stop)\n");
- return ret;
- }

- return 0;
+ kfree(local_transfer_buffer);
+ return ret;
}

static int usbduxfastsub_upload(struct usbduxfastsub_s *udfs,
--
1.7.9.5

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