Messages in this thread | | | Date | Thu, 13 Apr 2023 12:01:28 +0200 | From | Horatiu Vultur <> | Subject | Re: [PATCH net v2] net: ethernet: fix use after free bug in ns83820_remove_one due to race condition |
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The 04/13/2023 15:14, Zheng Wang wrote:
Hi Zheng,
> > 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. > > CPU0 CPU1 > > |queue_refill > ns83820_remove_one | > free_netdev | > put_device | > free ndev | > |rx_refill > |//use ndev
Will you not have the same issue if you remove the driver after you schedule rx_tasklet? Because rx_action will use also ndev.
> > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") > Signed-off-by: Zheng Wang <zyytlz.wz@163.com> > --- > v2: > - cancel the work after unregister_netdev to make sure there > is no more request suggested by Jakub Kicinski > --- > drivers/net/ethernet/natsemi/ns83820.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/net/ethernet/natsemi/ns83820.c b/drivers/net/ethernet/natsemi/ns83820.c > index 998586872599..2e84b9fcd8e9 100644 > --- a/drivers/net/ethernet/natsemi/ns83820.c > +++ b/drivers/net/ethernet/natsemi/ns83820.c > @@ -2208,8 +2208,13 @@ static void ns83820_remove_one(struct pci_dev *pci_dev) > > ns83820_disable_interrupts(dev); /* paranoia */ > > + netif_carrier_off(ndev); > + netif_tx_disable(ndev); > + > unregister_netdev(ndev); > free_irq(dev->pci_dev->irq, ndev); > + cancel_work_sync(&dev->tq_refill); > + > iounmap(dev->base); > dma_free_coherent(&dev->pci_dev->dev, 4 * DESC_SIZE * NR_TX_DESC, > dev->tx_descs, dev->tx_phy_descs); > -- > 2.25.1 >
-- /Horatiu
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