2023-03-11 17:09:37

by Zheng Wang

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

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 <[email protected]>
---
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");

--
2.25.1

2023-03-14 00:15:09

by Jakub Kicinski

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

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 <[email protected]>
> ---
> 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.

2023-03-14 02:12:30

by Zheng Hacker

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

Jakub Kicinski <[email protected]> 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 <[email protected]>
> > ---
> > 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