On Thu, Apr 7, 2022 at 10:40 AM Hangyu Hua <hbh25y@xxxxxxxxx> wrote:
>
> usb_put_dev shouldn't be called when uss720_probe succeeds because of
> priv->usbdev. At the same time, priv->usbdev shouldn't be set to NULL
> before destroy_priv in uss720_disconnect because usb_put_dev is in
> destroy_priv.
>
> Fix this by moving priv->usbdev = NULL after usb_put_dev.
Hi Hangyu,
good catch as priv->usbdev is still used after the probe function.
I agree with this patch.
Reviewed-by: Dongliang Mu <mudongliangabcd@xxxxxxxxx>
>
> Fixes: dcb4b8ad6a44 ("misc/uss720: fix memory leak in uss720_probe")
> Signed-off-by: Hangyu Hua <hbh25y@xxxxxxxxx>
> ---
>
> v2: fix a stupid UAF in the previous version.
>
> drivers/usb/misc/uss720.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/usb/misc/uss720.c b/drivers/usb/misc/uss720.c
> index 748139d26263..0be8efcda15d 100644
> --- a/drivers/usb/misc/uss720.c
> +++ b/drivers/usb/misc/uss720.c
> @@ -71,6 +71,7 @@ static void destroy_priv(struct kref *kref)
>
> dev_dbg(&priv->usbdev->dev, "destroying priv datastructure\n");
> usb_put_dev(priv->usbdev);
> + priv->usbdev = NULL;
> kfree(priv);
> }
>
> @@ -736,7 +737,6 @@ static int uss720_probe(struct usb_interface *intf,
> parport_announce_port(pp);
>
> usb_set_intfdata(intf, pp);
> - usb_put_dev(usbdev);
> return 0;
>
> probe_abort:
> @@ -754,7 +754,6 @@ static void uss720_disconnect(struct usb_interface *intf)
> usb_set_intfdata(intf, NULL);
> if (pp) {
> priv = pp->private_data;
> - priv->usbdev = NULL;
> priv->pp = NULL;
> dev_dbg(&intf->dev, "parport_remove_port\n");
> parport_remove_port(pp);
> --
> 2.25.1
>
