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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, Wen Yang <wen.yang99@zte.com.cn>,
        "David S. Miller" <davem@davemloft.net>,
        Thomas Gleixner <tglx@linutronix.de>,
        Luis Chamberlain <mcgrof@kernel.org>,
        Michael Ellerman <mpe@ellerman.id.au>, netdev@vger.kernel.org,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.4 110/183] net: pasemi: fix an use-after-free in pasemi_mac_phy_init()
Date:   Tue, 28 Jan 2020 15:05:29 +0100
Message-Id: <20200128135840.905748645@linuxfoundation.org>
In-Reply-To: <20200128135829.486060649@linuxfoundation.org>
References: <20200128135829.486060649@linuxfoundation.org>
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From: Wen Yang <wen.yang99@zte.com.cn>

[ Upstream commit faf5577f2498cea23011b5c785ef853ded22700b ]

The phy_dn variable is still being used in of_phy_connect() after the
of_node_put() call, which may result in use-after-free.

Fixes: 1dd2d06c0459 ("net: Rework pasemi_mac driver to use of_mdio infrastructure")
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/pasemi/pasemi_mac.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/pasemi/pasemi_mac.c b/drivers/net/ethernet/pasemi/pasemi_mac.c
index 57a6e6cd74fc3..48106953cf64b 100644
--- a/drivers/net/ethernet/pasemi/pasemi_mac.c
+++ b/drivers/net/ethernet/pasemi/pasemi_mac.c
@@ -1091,7 +1091,6 @@ static int pasemi_mac_phy_init(struct net_device *dev)
 
 	dn = pci_device_to_OF_node(mac->pdev);
 	phy_dn = of_parse_phandle(dn, "phy-handle", 0);
-	of_node_put(phy_dn);
 
 	mac->link = 0;
 	mac->speed = 0;
@@ -1100,6 +1099,7 @@ static int pasemi_mac_phy_init(struct net_device *dev)
 	phydev = of_phy_connect(dev, phy_dn, &pasemi_adjust_link, 0,
 				PHY_INTERFACE_MODE_SGMII);
 
+	of_node_put(phy_dn);
 	if (!phydev) {
 		printk(KERN_ERR "%s: Could not attach to phy\n", dev->name);
 		return -ENODEV;
-- 
2.20.1