vlan/macvlan: fix NULL pointer dereferences in ethtool handlers

Check whether the underlying device provides a set of ethtool ops before
checking for individual handlers to avoid NULL pointer dereferences.

Reported-by: Art van Breemen <ard@telegraafnet.nl>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index 1b34135cf990..6b0921364014 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -668,7 +668,8 @@ static int vlan_ethtool_get_settings(struct net_device *dev,
         const struct vlan_dev_info *vlan = vlan_dev_info(dev);
         struct net_device *real_dev = vlan->real_dev;
 
-        if (!real_dev->ethtool_ops->get_settings)
+        if (!real_dev->ethtool_ops ||
+            !real_dev->ethtool_ops->get_settings)
                 return -EOPNOTSUPP;
 
         return real_dev->ethtool_ops->get_settings(real_dev, cmd);