From ac61259087693b21e6cfdb76a4beabed70542db1 Mon Sep 17 00:00:00 2001

From: Pavel Skripkin <paskripkin@gmail.com>

Date: Fri, 18 Jun 2021 16:49:02 +0300

Subject: [PATCH 12/16] net: ethernet: fix potential use-after-free in

 ec_bhf_remove

Git-commit: 9cca0c2d70149160407bda9a9446ce0c29b6e6c6

Patch-mainline: v5.13-rc7

References: git-fixes

static void ec_bhf_remove(struct pci_dev *dev)

{

...

	struct ec_bhf_priv *priv = netdev_priv(net_dev);

	unregister_netdev(net_dev);

	free_netdev(net_dev);

	pci_iounmap(dev, priv->dma_io);

	pci_iounmap(dev, priv->io);

...

}

priv is netdev private data, but it is used

after free_netdev(). It can cause use-after-free when accessing priv

pointer. So, fix it by moving free_netdev() after pci_iounmap()

calls.

Fixes: 6af55ff52b02 ("Driver for Beckhoff CX5020 EtherCAT master module.")

Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>

Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>

---

 drivers/net/ethernet/ec_bhf.c | 4 +++-

 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/ec_bhf.c b/drivers/net/ethernet/ec_bhf.c

index b513c99d003b..8f2bc372ed89 100644

--- a/drivers/net/ethernet/ec_bhf.c

+++ b/drivers/net/ethernet/ec_bhf.c

@@ -585,10 +585,12 @@ static void ec_bhf_remove(struct pci_dev *dev)

 	struct ec_bhf_priv *priv = netdev_priv(net_dev);

 	unregister_netdev(net_dev);

-	free_netdev(net_dev);

 	pci_iounmap(dev, priv->dma_io);

 	pci_iounmap(dev, priv->io);

+

+	free_netdev(net_dev);

+

 	pci_release_regions(dev);

 	pci_clear_master(dev);

 	pci_disable_device(dev);

-- 

2.16.4