netdev - [PATCH] net: qcom/emac: fix UAF in emac

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Message-Id: <20210709142418.453-1-paskripkin@gmail.com>
Date:   Fri,  9 Jul 2021 17:24:18 +0300
From:   Pavel Skripkin <paskripkin@...il.com>
To:     timur@...nel.org, davem@...emloft.net, kuba@...nel.org
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Pavel Skripkin <paskripkin@...il.com>
Subject: [PATCH] net: qcom/emac: fix UAF in emac_remove

adpt is netdev private data and it cannot be
used after free_netdev() call. Using adpt after free_netdev()
can cause UAF bug. Fix it by moving free_netdev() at the end of the
function.

Fixes: 54e19bc74f33 ("net: qcom/emac: do not use devm on internal phy pdev")
Signed-off-by: Pavel Skripkin <paskripkin@...il.com>
---
 drivers/net/ethernet/qualcomm/emac/emac.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/qualcomm/emac/emac.c b/drivers/net/ethernet/qualcomm/emac/emac.c
index 8543bf3c3484..ad655f0a4965 100644
--- a/drivers/net/ethernet/qualcomm/emac/emac.c
+++ b/drivers/net/ethernet/qualcomm/emac/emac.c
@@ -735,12 +735,13 @@ static int emac_remove(struct platform_device *pdev)
 
 	put_device(&adpt->phydev->mdio.dev);
 	mdiobus_unregister(adpt->mii_bus);
-	free_netdev(netdev);
 
 	if (adpt->phy.digital)
 		iounmap(adpt->phy.digital);
 	iounmap(adpt->phy.base);
 
+	free_netdev(netdev);
+
 	return 0;
 }
 
-- 
2.32.0