Re: [PATCH v2] xirc2ps_cs: Fix use after free bug in xirc2ps_detach

[Zheng Hacker]

Jakub Kicinski <kuba@xxxxxxxxxx> 于2023年3月14日周二 08:15写道：
>
> On Sun, 12 Mar 2023 01:08:36 +0800 Zheng Wang wrote:
> > In xirc2ps_probe, the local->tx_timeout_task was bounded
> > with xirc2ps_tx_timeout_task. When timeout occurs,
> > it will call xirc_tx_timeout->schedule_work to start the
> > work.
> >
> > When we call xirc2ps_detach to remove the driver, there
> > may be a sequence as follows:
> >
> > Stop responding to timeout tasks and complete scheduled
> > tasks before cleanup in xirc2ps_detach, which will fix
> > the problem.
> >
> > CPU0                  CPU1
> >
> >                     |xirc2ps_tx_timeout_task
> > xirc2ps_detach      |
> >   free_netdev       |
> >     kfree(dev);     |
> >                     |
> >                     | do_reset
> >                     |   //use dev
> >
> > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> > Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>
> > ---
> > v2:
> > - fix indentation error suggested by Simon Horman,
> > and stop the timeout tasks  suggested by Yunsheng Lin
> > ---
> >  drivers/net/ethernet/xircom/xirc2ps_cs.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/drivers/net/ethernet/xircom/xirc2ps_cs.c b/drivers/net/ethernet/xircom/xirc2ps_cs.c
> > index 894e92ef415b..c77ca11d9497 100644
> > --- a/drivers/net/ethernet/xircom/xirc2ps_cs.c
> > +++ b/drivers/net/ethernet/xircom/xirc2ps_cs.c
> > @@ -503,6 +503,11 @@ static void
> >  xirc2ps_detach(struct pcmcia_device *link)
> >  {
> >      struct net_device *dev = link->priv;
> > +             struct local_info *local = netdev_priv(dev);
> > +
> > +             netif_carrier_off(dev);
> > +             netif_tx_disable(dev);
> > +             cancel_work_sync(&local->tx_timeout_task);
> >
> >      dev_dbg(&link->dev, "detach\n");
> >
>
> Please fix the formatting and make sure you CC the maintainers when you
> post v3.

Hi Jakub,

Get it!

Best regards,
Zheng