2023-03-09 09:43:34

by Zheng Wang

[permalink] [raw]
Subject: [PATCH net] net: ethernet: fix use after free bug in ns83820_remove_one due to race condition

In ns83820_init_one, dev->tq_refill was bound with queue_refill.

If irq happens, it will call ns83820_irq->ns83820_do_isr.
Then it invokes tasklet_schedule(&dev->rx_tasklet) to start
rx_action function. And rx_action will call ns83820_rx_kick
and finally start queue_refill function.

If we remove the driver without finishing the work, there
may be a race condition between ndev, which may cause UAF
bug.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Zheng Wang <[email protected]>
---
drivers/net/ethernet/natsemi/ns83820.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/natsemi/ns83820.c b/drivers/net/ethernet/natsemi/ns83820.c
index 998586872599..285fe0fa33eb 100644
--- a/drivers/net/ethernet/natsemi/ns83820.c
+++ b/drivers/net/ethernet/natsemi/ns83820.c
@@ -2206,6 +2206,7 @@ static void ns83820_remove_one(struct pci_dev *pci_dev)
if (!ndev) /* paranoia */
return;

+ cancel_work_sync(&dev->tq_refill);
ns83820_disable_interrupts(dev); /* paranoia */

unregister_netdev(ndev);
--
2.25.1



2023-03-13 23:26:36

by Jakub Kicinski

[permalink] [raw]
Subject: Re: [PATCH net] net: ethernet: fix use after free bug in ns83820_remove_one due to race condition

On Thu, 9 Mar 2023 17:42:31 +0800 Zheng Wang wrote:
> + cancel_work_sync(&dev->tq_refill);
> ns83820_disable_interrupts(dev); /* paranoia */
>
> unregister_netdev(ndev);

Canceling the work before unregister can't work.
Please take a closer look, the work to refill a ring should be
canceled when the ring itself is dismantled.

2023-03-14 02:00:13

by Zheng Hacker

[permalink] [raw]
Subject: Re: [PATCH net] net: ethernet: fix use after free bug in ns83820_remove_one due to race condition

Jakub Kicinski <[email protected]> 于2023年3月14日周二 07:26写道:
>
> On Thu, 9 Mar 2023 17:42:31 +0800 Zheng Wang wrote:
> > + cancel_work_sync(&dev->tq_refill);
> > ns83820_disable_interrupts(dev); /* paranoia */
> >
> > unregister_netdev(ndev);
>
> Canceling the work before unregister can't work.
> Please take a closer look, the work to refill a ring should be
> canceled when the ring itself is dismantled.

Hi Jakub,

Thanks for your review! After seeing code again, I found when handling
IRQ request, it will finally call ns83820_irq->ns83820_do_isr->
ns83820_rx_kick->schedule_work to start work. So I think we should
move the code after free_irq. What do you think?

Best regards,
Zheng

2023-03-15 04:10:37

by Jakub Kicinski

[permalink] [raw]
Subject: Re: [PATCH net] net: ethernet: fix use after free bug in ns83820_remove_one due to race condition

On Tue, 14 Mar 2023 09:59:09 +0800 Zheng Hacker wrote:
> Jakub Kicinski <[email protected]> 于2023年3月14日周二 07:26写道:
> > On Thu, 9 Mar 2023 17:42:31 +0800 Zheng Wang wrote:
> > > + cancel_work_sync(&dev->tq_refill);
> > > ns83820_disable_interrupts(dev); /* paranoia */
> > >
> > > unregister_netdev(ndev);
> >
> > Canceling the work before unregister can't work.
> > Please take a closer look, the work to refill a ring should be
> > canceled when the ring itself is dismantled.
>
> Hi Jakub,
>
> Thanks for your review! After seeing code again, I found when handling
> IRQ request, it will finally call ns83820_irq->ns83820_do_isr->
> ns83820_rx_kick->schedule_work to start work. So I think we should
> move the code after free_irq. What do you think?

Sorry, we have over 300 patches which need reviews. I don't have
the time to help you. Perhaps someone else will.

Please make sure you work on a single networking fix at a time.
All the patches you posted had the same issues.

2023-03-15 08:59:03

by Zheng Hacker

[permalink] [raw]
Subject: Re: [PATCH net] net: ethernet: fix use after free bug in ns83820_remove_one due to race condition

Jakub Kicinski <[email protected]> 于2023年3月15日周三 12:10写道:
>
> On Tue, 14 Mar 2023 09:59:09 +0800 Zheng Hacker wrote:
> > Jakub Kicinski <[email protected]> 于2023年3月14日周二 07:26写道:
> > > On Thu, 9 Mar 2023 17:42:31 +0800 Zheng Wang wrote:
> > > > + cancel_work_sync(&dev->tq_refill);
> > > > ns83820_disable_interrupts(dev); /* paranoia */
> > > >
> > > > unregister_netdev(ndev);
> > >
> > > Canceling the work before unregister can't work.
> > > Please take a closer look, the work to refill a ring should be
> > > canceled when the ring itself is dismantled.
> >
> > Hi Jakub,
> >
> > Thanks for your review! After seeing code again, I found when handling
> > IRQ request, it will finally call ns83820_irq->ns83820_do_isr->
> > ns83820_rx_kick->schedule_work to start work. So I think we should
> > move the code after free_irq. What do you think?
>
> Sorry, we have over 300 patches which need reviews. I don't have
> the time to help you. Perhaps someone else will.
>

Hi Jakub,

Thanks for your precious and kind reminder. I'll think about it again
and write the next version of patch.

> Please make sure you work on a single networking fix at a time.
> All the patches you posted had the same issues.

Yes, I'll keep that in mind.

Best regards,
Zheng