net: ethernet: ezchip: fix UAF in nps_enet_remove

[ Upstream commit e4b8700 ]

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 netif_napi_del()
call.

Fixes: 0dd0770 ("NET: Add ezchip ethernet 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/ezchip/nps_enet.c

@@ -645,8 +645,8 @@ static s32 nps_enet_remove(struct platform_device *pdev)
 	struct nps_enet_priv *priv = netdev_priv(ndev);
 
 	unregister_netdev(ndev);
-	free_netdev(ndev);
 	netif_napi_del(&priv->napi);
+	free_netdev(ndev);
 
 	return 0;
 }