Re: [PATCH net] net: ravb: Fix possible UAF bug in ravb_remove

[Sergey Shtylyov]

Hello!

On 3/9/23 1:02 PM, Zheng Wang wrote:

> In ravb_probe, priv->work was bound with ravb_tx_timeout_work.
> If timeout occurs, it will start the work. And if we call
> ravb_remove without finishing the work, ther may be a use
> after free bug on ndev.

   Have you actually encountered it?

> Fix it by finishing the job before cleanup in ravb_remove.
> 
> Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")

   Hm... sorry about that. :-)

> Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>

Reviewed-by: Sergey Shtylyov <s.shtylyov@xxxxxx>

[...]
> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
> index 0f54849a3823..07a08e72f440 100644
> --- a/drivers/net/ethernet/renesas/ravb_main.c
> +++ b/drivers/net/ethernet/renesas/ravb_main.c
> @@ -2892,6 +2892,7 @@ static int ravb_remove(struct platform_device *pdev)
>  	struct ravb_private *priv = netdev_priv(ndev);
>  	const struct ravb_hw_info *info = priv->info;
>  
> +	cancel_work_sync(&priv->work);

   I think we need an empty line here...

>  	/* Stop PTP Clock driver */
>  	if (info->ccc_gac)
>  		ravb_ptp_stop(ndev);

MBR, Sergey