[PATCH 4.14 28/82] net: qcom/emac: fix UAF in emac_remove

Greg Kroah-Hartman
2021-07-26T16:00:04Z

From: Pavel Skripkin <paskripkin@gmail.com>

commit ad297cd2db8953e2202970e9504cab247b6c7cb4 upstream.

adpt is netdev private data and it cannot be
used after free_netdev() call. Using adpt after free_netdev()
can cause UAF bug. Fix it by moving free_netdev() at the end of the
function.

Fixes: 54e19bc74f33 ("net: qcom/emac: do not use devm on internal phy pdev")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/qualcomm/emac/emac.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/qualcomm/emac/emac.c
+++ b/drivers/net/ethernet/qualcomm/emac/emac.c
@@ -765,12 +765,13 @@ static int emac_remove(struct platform_d

put_device(&adpt->phydev->mdio.dev);
mdiobus_unregister(adpt->mii_bus);
- free_netdev(netdev);

if (adpt->phy.digital)
iounmap(adpt->phy.digital);
iounmap(adpt->phy.base);

+ free_netdev(netdev);
+
return 0;
}