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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Dan Carpenter <dan.carpenter@oracle.com>,
        Amey Narkhede <ameynarkhede03@gmail.com>
Subject: [PATCH 4.19 210/247] staging: gdm724x: Fix DMA from stack
Date:   Mon,  1 Mar 2021 17:13:50 +0100
Message-Id: <20210301161041.958899544@linuxfoundation.org>
In-Reply-To: <20210301161031.684018251@linuxfoundation.org>
References: <20210301161031.684018251@linuxfoundation.org>
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From: Amey Narkhede <ameynarkhede03@gmail.com>

commit 7c3a0635cd008eaca9a734dc802709ee0b81cac5 upstream.

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

Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>
Link: https://lore.kernel.org/r/20210211053819.34858-1-ameynarkhede03@gmail.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/staging/gdm724x/gdm_usb.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

--- 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;
 }