[PATCH 4.4 070/188] net: ethernet: aeroflex: fix UAF in greth_of_remove

Greg Kroah-Hartman
2021-07-19T15:00:09Z

From: Pavel Skripkin <paskripkin@gmail.com>

[ 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@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 20bf55dbd76f..e3ca8abb14f4 100644
--- a/drivers/net/ethernet/aeroflex/greth.c
+++ b/drivers/net/ethernet/aeroflex/greth.c
@@ -1579,10 +1579,11 @@ 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