linux-kernel - Re: [PATCH v2] staging: gdm724x: Fix DMA from stack

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 10 Feb 2021 09:06:56 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Amey Narkhede <ameynarkhede03@...il.com>
Cc:     dan.carpenter@...cle.com, devel@...verdev.osuosl.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] staging: gdm724x: Fix DMA from stack

On Wed, Feb 10, 2021 at 01:31:34PM +0530, Amey Narkhede wrote:
> Stack allocated buffers cannot be used for DMA
> on all architectures so allocate hci_packet buffer
> using kzalloc().
> 
> Signed-off-by: Amey Narkhede <ameynarkhede03@...il.com>
> ---
> Changes in v2:
> 	- Fixed build warning
> 	- Fixed memory leak using kfree
> 
>  drivers/staging/gdm724x/gdm_usb.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/staging/gdm724x/gdm_usb.c b/drivers/staging/gdm724x/gdm_usb.c
> index dc4da66c3..c4a9b90c5 100644
> --- a/drivers/staging/gdm724x/gdm_usb.c
> +++ b/drivers/staging/gdm724x/gdm_usb.c
> @@ -56,11 +56,15 @@ 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;
> +	u8 *buf;
> +	struct hci_packet *hci;
>  	struct usb_device *usbdev = udev->usbdev;
>  	int actual;
>  	int ret = -1;
> +	buf = kzalloc(16, GFP_KERNEL);

checkpatch did not complain about this?

And why do you need 'buf' anymore now?  Why not just allocate hci and
pass that to the request instead?  Saves you an extra cast and an extra
pointer.

thanks,

greg k-h