epic100: fix use after free on rmmod

epic_close() calls epic_rx() and uses dma buffer, but in epic_remove_one()
we already freed the dma buffer. To fix this issue, reorder function calls
like in the .probe function.

BUG: KASAN: use-after-free in epic_rx+0xa6/0x7e0 [epic100]
Call Trace:
 epic_rx+0xa6/0x7e0 [epic100]
 epic_close+0xec/0x2f0 [epic100]
 unregister_netdev+0x18/0x20
 epic_remove_one+0xaa/0xf0 [epic100]

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: Yilun Wu <yiluwu@cs.stonybrook.edu>
Signed-off-by: Tong Zhang <ztong0001@gmail.com>
Reviewed-by: Francois Romieu <romieu@fr.zoreil.com>
Link: https://lore.kernel.org/r/20220627043351.25615-1-ztong0001@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/smsc/epic100.c b/drivers/net/ethernet/smsc/epic100.c
index a0654e8..0329caf 100644 (file)
--- a/drivers/net/ethernet/smsc/epic100.c
+++ b/drivers/net/ethernet/smsc/epic100.c
@@ -1515,14 +1515,14 @@ static void epic_remove_one(struct pci_dev *pdev)
        struct net_device *dev = pci_get_drvdata(pdev);
        struct epic_private *ep = netdev_priv(dev);
 
+       unregister_netdev(dev);
        dma_free_coherent(&pdev->dev, TX_TOTAL_SIZE, ep->tx_ring,
                          ep->tx_ring_dma);
        dma_free_coherent(&pdev->dev, RX_TOTAL_SIZE, ep->rx_ring,
                          ep->rx_ring_dma);
-       unregister_netdev(dev);
        pci_iounmap(pdev, ep->ioaddr);
-       pci_release_regions(pdev);
        free_netdev(dev);
+       pci_release_regions(pdev);
        pci_disable_device(pdev);
        /* pci_power_off(pdev, -1); */
 }