[VLAN]: Fix promiscous/allmulti synchronization races

The set_multicast_list function may be called without holding the rtnl
mutex, resulting in races when changing the underlying device's promiscous
and allmulti state. Use the change_rx_mode hook, which is always invoked
under the rtnl.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 22 insertions, 18 deletions

diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
index abb9900edb3f..39bdcc25c150 100644
--- a/net/8021q/vlan.c
+++ b/net/8021q/vlan.c
@@ -373,6 +373,7 @@ void vlan_setup(struct net_device *new_dev)
         new_dev->open = vlan_dev_open;
         new_dev->stop = vlan_dev_stop;
         new_dev->set_multicast_list = vlan_dev_set_multicast_list;
+        new_dev->change_rx_flags = vlan_change_rx_flags;
         new_dev->destructor = free_netdev;
         new_dev->do_ioctl = vlan_dev_ioctl;
 
diff --git a/net/8021q/vlan.h b/net/8021q/vlan.h
index 62ce1c519aab..7df5b2935579 100644
--- a/net/8021q/vlan.h
+++ b/net/8021q/vlan.h
@@ -69,6 +69,7 @@ int vlan_dev_set_vlan_flag(const struct net_device *dev,
                            u32 flag, short flag_val);
 void vlan_dev_get_realdev_name(const struct net_device *dev, char *result);
 void vlan_dev_get_vid(const struct net_device *dev, unsigned short *result);
+void vlan_change_rx_flags(struct net_device *dev, int change);
 void vlan_dev_set_multicast_list(struct net_device *vlan_dev);
 
 int vlan_check_real_dev(struct net_device *real_dev, unsigned short vlan_id);
diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index d4a62d1b52b4..dec7e62b2e10 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -712,6 +712,11 @@ int vlan_dev_open(struct net_device *dev)
         }
         memcpy(vlan->real_dev_addr, real_dev->dev_addr, ETH_ALEN);
 
+        if (dev->flags & IFF_ALLMULTI)
+                dev_set_allmulti(real_dev, 1);
+        if (dev->flags & IFF_PROMISC)
+                dev_set_promiscuity(real_dev, 1);
+
         return 0;
 }
 
@@ -721,6 +726,11 @@ int vlan_dev_stop(struct net_device *dev)
 
         vlan_flush_mc_list(dev);
 
+        if (dev->flags & IFF_ALLMULTI)
+                dev_set_allmulti(real_dev, -1);
+        if (dev->flags & IFF_PROMISC)
+                dev_set_promiscuity(real_dev, -1);
+
         if (compare_ether_addr(dev->dev_addr, real_dev->dev_addr))
                 dev_unicast_delete(real_dev, dev->dev_addr, dev->addr_len);
 
@@ -754,34 +764,26 @@ int vlan_dev_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
         return err;
 }
 
+void vlan_change_rx_flags(struct net_device *dev, int change)
+{
+        struct net_device *real_dev = VLAN_DEV_INFO(dev)->real_dev;
+
+        if (change & IFF_ALLMULTI)
+                dev_set_allmulti(real_dev, dev->flags & IFF_ALLMULTI ? 1 : -1);
+        if (change & IFF_PROMISC)
+                dev_set_promiscuity(real_dev, dev->flags & IFF_PROMISC ? 1 : -1);
+}
+
 /** Taken from Gleb + Lennert's VLAN code, and modified... */
 void vlan_dev_set_multicast_list(struct net_device *vlan_dev)
 {
         struct dev_mc_list *dmi;
         struct net_device *real_dev;
-        int inc;
 
         if (vlan_dev && (vlan_dev->priv_flags & IFF_802_1Q_VLAN)) {
                 /* Then it's a real vlan device, as far as we can tell.. */
                 real_dev = VLAN_DEV_INFO(vlan_dev)->real_dev;
 
-                /* compare the current promiscuity to the last promisc we had.. */
-                inc = vlan_dev->promiscuity - VLAN_DEV_INFO(vlan_dev)->old_promiscuity;
-                if (inc) {
-                        printk(KERN_INFO "%s: dev_set_promiscuity(master, %d)\n",
-                               vlan_dev->name, inc);
-                        dev_set_promiscuity(real_dev, inc); /* found in dev.c */
-                        VLAN_DEV_INFO(vlan_dev)->old_promiscuity = vlan_dev->promiscuity;
-                }
-
-                inc = vlan_dev->allmulti - VLAN_DEV_INFO(vlan_dev)->old_allmulti;
-                if (inc) {
-                        printk(KERN_INFO "%s: dev_set_allmulti(master, %d)\n",
-                               vlan_dev->name, inc);
-                        dev_set_allmulti(real_dev, inc); /* dev.c */
-                        VLAN_DEV_INFO(vlan_dev)->old_allmulti = vlan_dev->allmulti;
-                }
-
                 /* looking for addresses to add to master's list */
                 for (dmi = vlan_dev->mc_list; dmi != NULL; dmi = dmi->next) {
                         if (vlan_should_add_mc(dmi, VLAN_DEV_INFO(vlan_dev)->old_mc_list)) {