can: c_can_pci: c_can_pci_remove(): fix use-after-free

There is a UAF in c_can_pci_remove(). dev is released by
free_c_can_dev() and is used by pci_iounmap(pdev, priv->base) later.
To fix this issue, save the mmio address before releasing dev.

Fixes: 5b92da0443c2 ("c_can_pci: generic module for C_CAN/D_CAN on PCI")
Link: https://lore.kernel.org/r/20210301024512.539039-1-ztong0001@gmail.com
Signed-off-by: Tong Zhang <ztong0001@gmail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/c_can/c_can_pci.c b/drivers/net/can/c_can/c_can_pci.c
index 406b4847e5dc323c35d444a7cfabda4119404c70..7efb60b50876288bc33d6e7449663fd2e821497a 100644 (file)
--- a/drivers/net/can/c_can/c_can_pci.c
+++ b/drivers/net/can/c_can/c_can_pci.c
@@ -239,12 +239,13 @@ static void c_can_pci_remove(struct pci_dev *pdev)
 {
        struct net_device *dev = pci_get_drvdata(pdev);
        struct c_can_priv *priv = netdev_priv(dev);
+       void __iomem *addr = priv->base;
 
        unregister_c_can_dev(dev);
 
        free_c_can_dev(dev);
 
-       pci_iounmap(pdev, priv->base);
+       pci_iounmap(pdev, addr);
        pci_disable_msi(pdev);
        pci_clear_master(pdev);
        pci_release_regions(pdev);