net: dsa: Fix NPD checking for br_vlan_enabled()

[ Upstream not applicable ]

It is possible for the DSA slave network device not to be part of a
bridge, yet have an upper device like a VLAN device be part of a bridge.
When that VLAN device is enslaved, since it does not define any
switchdev_ops, we will recurse down to the lower/physical port device,
call switchdev_port_obj_add() with a VLAN, and here we will check
br_vlan_enabled() on a NULL dp->bridge_dev, thus causing a NULL pointer
de-reference.

This is no longer a problem upstream after commit d17d9f5e5143
("switchdev: Replace port obj add/del SDO with a notification").

Fixes: 2ea7a679ca2a ("net: dsa: Don't add vlans when vlan filtering is disabled")
Reported-by: Frank Wunderlich <frank-w@public-files.de>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/dsa/port.c b/net/dsa/port.c
index ed0595459df13e61c10bd18fe0025d61f5837d97..792a13068c50b80ef0063c4cfb4b629a330d3bb1 100644 (file)
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -255,7 +255,7 @@ int dsa_port_vlan_add(struct dsa_port *dp,
        if (netif_is_bridge_master(vlan->obj.orig_dev))
                return -EOPNOTSUPP;
 
-       if (br_vlan_enabled(dp->bridge_dev))
+       if (dp->bridge_dev && br_vlan_enabled(dp->bridge_dev))
                return dsa_port_notify(dp, DSA_NOTIFIER_VLAN_ADD, &info);
 
        return 0;
@@ -273,7 +273,7 @@ int dsa_port_vlan_del(struct dsa_port *dp,
        if (netif_is_bridge_master(vlan->obj.orig_dev))
                return -EOPNOTSUPP;
 
-       if (br_vlan_enabled(dp->bridge_dev))
+       if (dp->bridge_dev && br_vlan_enabled(dp->bridge_dev))
                return dsa_port_notify(dp, DSA_NOTIFIER_VLAN_DEL, &info);
 
        return 0;