1 files changed, 36 insertions, 0 deletions

diff --git a/net/wireless/util.c b/net/wireless/util.c
index 5aa39f7cf9b9..59361fdcb5d0 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -658,7 +658,14 @@ int cfg80211_change_iface(struct cfg80211_registered_device *rdev,
             !(rdev->wiphy.interface_modes & (1 << ntype)))
                 return -EOPNOTSUPP;
 
+        /* if it's part of a bridge, reject changing type to station/ibss */
+        if (dev->br_port && (ntype == NL80211_IFTYPE_ADHOC ||
+                             ntype == NL80211_IFTYPE_STATION))
+                return -EBUSY;
+
         if (ntype != otype) {
+                dev->ieee80211_ptr->use_4addr = false;
+
                 switch (otype) {
                 case NL80211_IFTYPE_ADHOC:
                         cfg80211_leave_ibss(rdev, dev, false);
@@ -682,5 +689,34 @@ int cfg80211_change_iface(struct cfg80211_registered_device *rdev,
 
         WARN_ON(!err && dev->ieee80211_ptr->iftype != ntype);
 
+        if (!err && params && params->use_4addr != -1)
+                dev->ieee80211_ptr->use_4addr = params->use_4addr;
+
+        if (!err) {
+                dev->priv_flags &= ~IFF_DONT_BRIDGE;
+                switch (ntype) {
+                case NL80211_IFTYPE_STATION:
+                        if (dev->ieee80211_ptr->use_4addr)
+                                break;
+                        /* fall through */
+                case NL80211_IFTYPE_ADHOC:
+                        dev->priv_flags |= IFF_DONT_BRIDGE;
+                        break;
+                case NL80211_IFTYPE_AP:
+                case NL80211_IFTYPE_AP_VLAN:
+                case NL80211_IFTYPE_WDS:
+                case NL80211_IFTYPE_MESH_POINT:
+                        /* bridging OK */
+                        break;
+                case NL80211_IFTYPE_MONITOR:
+                        /* monitor can't bridge anyway */
+                        break;
+                case NL80211_IFTYPE_UNSPECIFIED:
+                case __NL80211_IFTYPE_AFTER_LAST:
+                        /* not happening */
+                        break;
+                }
+        }
+
         return err;
 }