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

[Zheng Wang]

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 <zyytlz.wz@xxxxxxx>
---
 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