1 files changed, 38 insertions, 0 deletions

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index f5537f90dd36..93dcdc27254b 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -187,9 +187,15 @@ static int ieee80211_open(struct net_device *dev)
         u32 changed = 0;
         int res;
         bool need_hw_reconfig = 0;
+        u8 null_addr[ETH_ALEN] = {0};
 
         sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 
+        /* fail early if user set an invalid address */
+        if (compare_ether_addr(dev->dev_addr, null_addr) &&
+            !is_valid_ether_addr(dev->dev_addr))
+                return -EADDRNOTAVAIL;
+
         /* we hold the RTNL here so can safely walk the list */
         list_for_each_entry(nsdata, &local->interfaces, list) {
                 struct net_device *ndev = nsdata->dev;
@@ -270,6 +276,36 @@ static int ieee80211_open(struct net_device *dev)
                 ieee80211_led_radio(local, local->hw.conf.radio_enabled);
         }
 
+        /*
+         * Check all interfaces and copy the hopefully now-present
+         * MAC address to those that have the special null one.
+         */
+        list_for_each_entry(nsdata, &local->interfaces, list) {
+                struct net_device *ndev = nsdata->dev;
+
+                /*
+                 * No need to check netif_running since we do not allow
+                 * it to start up with this invalid address.
+                 */
+                if (compare_ether_addr(null_addr, ndev->dev_addr) == 0)
+                        memcpy(ndev->dev_addr,
+                               local->hw.wiphy->perm_addr,
+                               ETH_ALEN);
+        }
+
+        if (compare_ether_addr(null_addr, local->mdev->dev_addr) == 0)
+                memcpy(local->mdev->dev_addr, local->hw.wiphy->perm_addr,
+                       ETH_ALEN);
+
+        /*
+         * Validate the MAC address for this device.
+         */
+        if (!is_valid_ether_addr(dev->dev_addr)) {
+                if (!local->open_count && local->ops->stop)
+                        local->ops->stop(local_to_hw(local));
+                return -EADDRNOTAVAIL;
+        }
+
         switch (sdata->vif.type) {
         case IEEE80211_IF_TYPE_VLAN:
                 /* no need to tell driver */
@@ -975,6 +1011,8 @@ void ieee80211_if_setup(struct net_device *dev)
         dev->open = ieee80211_open;
         dev->stop = ieee80211_stop;
         dev->destructor = free_netdev;
+        /* we will validate the address ourselves in ->open */
+        dev->validate_addr = NULL;
 }
 
 /* everything else */