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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, Pavel Skripkin <paskripkin@gmail.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.19 043/120] net: qcom/emac: fix UAF in emac_remove
Date:   Mon, 26 Jul 2021 17:38:15 +0200
Message-Id: <20210726153833.776321471@linuxfoundation.org>
In-Reply-To: <20210726153832.339431936@linuxfoundation.org>
References: <20210726153832.339431936@linuxfoundation.org>
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From: Pavel Skripkin <paskripkin@gmail.com>

commit ad297cd2db8953e2202970e9504cab247b6c7cb4 upstream.

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@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/qualcomm/emac/emac.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/qualcomm/emac/emac.c
+++ b/drivers/net/ethernet/qualcomm/emac/emac.c
@@ -759,12 +759,13 @@ static int emac_remove(struct platform_d
 
 	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;
 }