ethernet: ucc_geth: fix use-after-free in ucc_geth_remove()

[ Upstream commit e925e0c ]

ugeth is the netdiv_priv() part of the netdevice. Accessing the memory
pointed to by ugeth (such as done by ucc_geth_memclean() and the two
of_node_puts) after free_netdev() is thus use-after-free.

Fixes: 80a9fad ("ucc_geth: fix module removal")
Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/ethernet/freescale/ucc_geth.c

@@ -3934,12 +3934,12 @@ static int ucc_geth_remove(struct platform_device* ofdev)
 	struct device_node *np = ofdev->dev.of_node;
 
 	unregister_netdev(dev);
-	free_netdev(dev);
 	ucc_geth_memclean(ugeth);
 	if (of_phy_is_fixed_link(np))
 		of_phy_deregister_fixed_link(np);
 	of_node_put(ugeth->ug_info->tbi_node);
 	of_node_put(ugeth->ug_info->phy_node);
+	free_netdev(dev);
 
 	return 0;
 }