From 0429d6d89f97ebff4f17f13f5b5069c66bde8138 Mon Sep 17 00:00:00 2001

From: Tong Zhang <ztong0001@gmail.com>

Date: Sun, 28 Feb 2021 21:45:11 -0500

Subject: [PATCH] can: c_can_pci: c_can_pci_remove(): fix use-after-free

Git-commit: 0429d6d89f97ebff4f17f13f5b5069c66bde8138

Patch-mainline: v5.12-rc5

References: git-fixes

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>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 drivers/net/can/c_can/c_can_pci.c | 3 ++-

 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/c_can/c_can_pci.c b/drivers/net/can/c_can/c_can_pci.c

index 406b4847e5dc..7efb60b50876 100644

--- 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);

-- 

2.26.2