[for-3.18,03/15] sh_eth: Fix ethtool operation crash when net device is down

Message ID 1501015526-32178-4-git-send-email-amit.pundir@linaro.org
State New
Headers show
Series
  • Stable candidates for 3.18.y
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Commit Message

Amit Pundir July 25, 2017, 8:45 p.m.
From: Ben Hutchings <ben.hutchings@codethink.co.uk>


commit 4f9dce230b32eec45cec8c28cae61efdfa2f7d57 upstream.

The driver connects and disconnects the PHY device whenever the
net device is brought up and down.  The ethtool get_settings,
set_settings and nway_reset operations will dereference a null
or dangling pointer if called while it is down.

I think it would be preferable to keep the PHY connected, but there
may be good reasons not to.

As an immediate fix for this bug:
- Set the phydev pointer to NULL after disconnecting the PHY
- Change those three operations to return -ENODEV while the PHY is
  not connected

Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>

Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Amit Pundir <amit.pundir@linaro.org>

---
 drivers/net/ethernet/renesas/sh_eth.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

-- 
2.7.4

Patch

diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c
index c44bae495804..f25b5b8b120f 100644
--- a/drivers/net/ethernet/renesas/sh_eth.c
+++ b/drivers/net/ethernet/renesas/sh_eth.c
@@ -1832,6 +1832,9 @@  static int sh_eth_get_settings(struct net_device *ndev,
 	unsigned long flags;
 	int ret;
 
+	if (!mdp->phydev)
+		return -ENODEV;
+
 	spin_lock_irqsave(&mdp->lock, flags);
 	ret = phy_ethtool_gset(mdp->phydev, ecmd);
 	spin_unlock_irqrestore(&mdp->lock, flags);
@@ -1846,6 +1849,9 @@  static int sh_eth_set_settings(struct net_device *ndev,
 	unsigned long flags;
 	int ret;
 
+	if (!mdp->phydev)
+		return -ENODEV;
+
 	spin_lock_irqsave(&mdp->lock, flags);
 
 	/* disable tx and rx */
@@ -1880,6 +1886,9 @@  static int sh_eth_nway_reset(struct net_device *ndev)
 	unsigned long flags;
 	int ret;
 
+	if (!mdp->phydev)
+		return -ENODEV;
+
 	spin_lock_irqsave(&mdp->lock, flags);
 	ret = phy_start_aneg(mdp->phydev);
 	spin_unlock_irqrestore(&mdp->lock, flags);
@@ -2189,6 +2198,7 @@  static int sh_eth_close(struct net_device *ndev)
 	if (mdp->phydev) {
 		phy_stop(mdp->phydev);
 		phy_disconnect(mdp->phydev);
+		mdp->phydev = NULL;
 	}
 
 	free_irq(ndev->irq, ndev);