[PATCH v4] staging: gdm724x: Fix DMA from stack

* [PATCH v4] staging: gdm724x: Fix DMA from stack
@ 2021-02-11  5:38 Amey Narkhede
  2021-02-11  7:15 ` Dan Carpenter
  2021-02-11 13:28 ` David Laight
  0 siblings, 2 replies; 4+ messages in thread
From: Amey Narkhede @ 2021-02-11  5:38 UTC (permalink / raw)
  To: gregkh, dan.carpenter; +Cc: devel, Amey Narkhede, linux-kernel

Stack allocated buffers cannot be used for DMA
on all architectures so allocate hci_packet buffer
using kmalloc.

Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>
---
Changes in v4:
	- Use struct_size to allocate memory for hci_packet
	- Fix memory corruption

 drivers/staging/gdm724x/gdm_usb.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/gdm724x/gdm_usb.c b/drivers/staging/gdm724x/gdm_usb.c
index dc4da66c3..54bdb64f5 100644
--- a/drivers/staging/gdm724x/gdm_usb.c
+++ b/drivers/staging/gdm724x/gdm_usb.c
@@ -56,20 +56,24 @@ static int gdm_usb_recv(void *priv_dev,

 static int request_mac_address(struct lte_udev *udev)
 {
-	u8 buf[16] = {0,};
-	struct hci_packet *hci = (struct hci_packet *)buf;
+	struct hci_packet *hci;
 	struct usb_device *usbdev = udev->usbdev;
 	int actual;
 	int ret = -1;

+	hci = kmalloc(struct_size(hci, data, 1), GFP_KERNEL);
+	if (!hci)
+		return -ENOMEM;
+
 	hci->cmd_evt = gdm_cpu_to_dev16(udev->gdm_ed, LTE_GET_INFORMATION);
 	hci->len = gdm_cpu_to_dev16(udev->gdm_ed, 1);
 	hci->data[0] = MAC_ADDRESS;

-	ret = usb_bulk_msg(usbdev, usb_sndbulkpipe(usbdev, 2), buf, 5,
+	ret = usb_bulk_msg(usbdev, usb_sndbulkpipe(usbdev, 2), hci, 5,
 			   &actual, 1000);

 	udev->request_mac_addr = 1;
+	kfree(hci);

 	return ret;
 }
--
2.30.1
_______________________________________________
devel mailing list
devel@linuxdriverproject.org
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel

^ permalink raw reply related	[flat|nested] 4+ messages in thread