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

[Zheng Hacker]

Sergey Shtylyov <s.shtylyov@xxxxxx> 于2023年3月9日周四 23:47写道：
>
> 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?

Sorry, I haven't encountered it. All of the analysis is based on
static analysis.

>
> > 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...

Yes, will add it in the next version of patch.

Best regards,
Zheng

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