[PATCH 4.19 142/421] net: ethernet: aeroflex: fix UAF in greth_of_remove

[Greg Kroah-Hartman]

From: Pavel Skripkin <paskripkin@xxxxxxxxx>

[ Upstream commit e3a5de6d81d8b2199935c7eb3f7d17a50a7075b7 ]

static int greth_of_remove(struct platform_device *of_dev)
{
...
	struct greth_private *greth = netdev_priv(ndev);
...
	unregister_netdev(ndev);
	free_netdev(ndev);

	of_iounmap(&of_dev->resource[0], greth->regs, resource_size(&of_dev->resource[0]));
...
}

greth is netdev private data, but it is used
after free_netdev(). It can cause use-after-free when accessing greth
pointer. So, fix it by moving free_netdev() after of_iounmap()
call.

Fixes: d4c41139df6e ("net: Add Aeroflex Gaisler 10/100/1G Ethernet MAC driver")
Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/net/ethernet/aeroflex/greth.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/aeroflex/greth.c b/drivers/net/ethernet/aeroflex/greth.c
index 4309be3724ad..a20e95b39cf7 100644
--- a/drivers/net/ethernet/aeroflex/greth.c
+++ b/drivers/net/ethernet/aeroflex/greth.c
@@ -1546,10 +1546,11 @@ static int greth_of_remove(struct platform_device *of_dev)
 	mdiobus_unregister(greth->mdio);
 
 	unregister_netdev(ndev);
-	free_netdev(ndev);
 
 	of_iounmap(&of_dev->resource[0], greth->regs, resource_size(&of_dev->resource[0]));
 
+	free_netdev(ndev);
+
 	return 0;
 }
 
-- 
2.30.2