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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Rasmus Villemoes <rasmus.villemoes@prevas.dk>,
        Jakub Kicinski <kuba@kernel.org>
Subject: [PATCH 5.4 15/92] ethernet: ucc_geth: fix use-after-free in ucc_geth_remove()
Date:   Mon, 11 Jan 2021 14:01:19 +0100
Message-Id: <20210111130039.895843678@linuxfoundation.org>
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From: Rasmus Villemoes <rasmus.villemoes@prevas.dk>

[ Upstream commit e925e0cd2a705aaacb0b907bb3691fcac3a973a4 ]

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: 80a9fad8e89a ("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 |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/ethernet/freescale/ucc_geth.c
+++ b/drivers/net/ethernet/freescale/ucc_geth.c
@@ -3935,12 +3935,12 @@ static int ucc_geth_remove(struct platfo
 	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;
 }