[PATCH] net: pasemi: fix an use-after-free in pasemi_mac_phy_init()

[PATCH] net: pasemi: fix an use-after-free in pasemi_mac_phy_init()

[Wen Yang]

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
---
 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 bf5a7bc..be66601 100644
--- a/drivers/net/ethernet/pasemi/pasemi_mac.c
+++ b/drivers/net/ethernet/pasemi/pasemi_mac.c
@@ -1042,7 +1042,6 @@ 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;
@@ -1051,6 +1050,7 @@ 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;
-- 
2.9.5

Re: [PATCH] net: pasemi: fix an use-after-free in pasemi_mac_phy_init()

[David Miller]

From: Wen Yang <wen.yang99@zte.com.cn>
Date: Sat, 6 Jul 2019 12:23:41 +0800

> 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>

Applied.