cfg80211: clear WEXT SSID when clearing IBSS

When we leave an IBSS, we should clear the SSID and not just the
BSSID, but since WEXT allows configuring while the interface is
down we must not clear it when leaving due to taking the iface
down, so some complications are needed.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/wireless/core.c

@@ -464,7 +464,7 @@ static int cfg80211_netdev_notifier_call(struct notifier_block * nb,
 			break;
 		if (!dev->ieee80211_ptr->ssid_len)
 			break;
-		cfg80211_leave_ibss(rdev, dev);
+		cfg80211_leave_ibss(rdev, dev, true);
 		break;
 	case NETDEV_UP:
 #ifdef CONFIG_WIRELESS_EXT

net/wireless/core.h

@@ -147,8 +147,8 @@ void cfg80211_bss_age(struct cfg80211_registered_device *dev,
 int cfg80211_join_ibss(struct cfg80211_registered_device *rdev,
 		       struct net_device *dev,
 		       struct cfg80211_ibss_params *params);
-void cfg80211_clear_ibss(struct net_device *dev);
+void cfg80211_clear_ibss(struct net_device *dev, bool nowext);
 int cfg80211_leave_ibss(struct cfg80211_registered_device *rdev,
-			struct net_device *dev);
+			struct net_device *dev, bool nowext);
 
 #endif /* __NET_WIRELESS_CORE_H */

net/wireless/ibss.c

@@ -76,7 +76,7 @@ int cfg80211_join_ibss(struct cfg80211_registered_device *rdev,
 	return 0;
 }
 
-void cfg80211_clear_ibss(struct net_device *dev)
+void cfg80211_clear_ibss(struct net_device *dev, bool nowext)
 {
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
 
@@ -88,10 +88,14 @@ void cfg80211_clear_ibss(struct net_device *dev)
 	wdev->current_bss = NULL;
 	wdev->ssid_len = 0;
 	memset(wdev->bssid, 0, ETH_ALEN);
+#ifdef CONFIG_WIRELESS_EXT
+	if (!nowext)
+		wdev->wext.ssid_len = 0;
+#endif
 }
 
 int cfg80211_leave_ibss(struct cfg80211_registered_device *rdev,
-			struct net_device *dev)
+			struct net_device *dev, bool nowext)
 {
 	int err;
 
@@ -100,7 +104,7 @@ int cfg80211_leave_ibss(struct cfg80211_registered_device *rdev,
 	if (err)
 		return err;
 
-	cfg80211_clear_ibss(dev);
+	cfg80211_clear_ibss(dev, nowext);
 
 	return 0;
 }
@@ -179,7 +183,8 @@ int cfg80211_ibss_wext_siwfreq(struct net_device *dev,
 		return 0;
 
 	if (wdev->ssid_len) {
-		err = cfg80211_leave_ibss(wiphy_to_dev(wdev->wiphy), dev);
+		err = cfg80211_leave_ibss(wiphy_to_dev(wdev->wiphy),
+					  dev, true);
 		if (err)
 			return err;
 	}
@@ -241,7 +246,8 @@ int cfg80211_ibss_wext_siwessid(struct net_device *dev,
 		return -EOPNOTSUPP;
 
 	if (wdev->ssid_len) {
-		err = cfg80211_leave_ibss(wiphy_to_dev(wdev->wiphy), dev);
+		err = cfg80211_leave_ibss(wiphy_to_dev(wdev->wiphy),
+					  dev, true);
 		if (err)
 			return err;
 	}
@@ -275,7 +281,7 @@ int cfg80211_ibss_wext_giwessid(struct net_device *dev,
 		data->flags = 1;
 		data->length = wdev->ssid_len;
 		memcpy(ssid, wdev->ssid, data->length);
-	} else if (wdev->wext.ssid) {
+	} else if (wdev->wext.ssid && wdev->wext.ssid_len) {
 		data->flags = 1;
 		data->length = wdev->wext.ssid_len;
 		memcpy(ssid, wdev->wext.ssid, data->length);
@@ -318,7 +324,8 @@ int cfg80211_ibss_wext_siwap(struct net_device *dev,
 		return 0;
 
 	if (wdev->ssid_len) {
-		err = cfg80211_leave_ibss(wiphy_to_dev(wdev->wiphy), dev);
+		err = cfg80211_leave_ibss(wiphy_to_dev(wdev->wiphy),
+					  dev, true);
 		if (err)
 			return err;
 	}

net/wireless/nl80211.c

@@ -833,7 +833,7 @@ static int nl80211_set_interface(struct sk_buff *skb, struct genl_info *info)
 
 	if (dev && !err && (ntype != otype)) {
 		if (otype == NL80211_IFTYPE_ADHOC)
-			cfg80211_clear_ibss(dev);
+			cfg80211_clear_ibss(dev, false);
 	}
 
  unlock:
@@ -3249,7 +3249,7 @@ static int nl80211_leave_ibss(struct sk_buff *skb, struct genl_info *info)
 		goto out;
 	}
 
-	err = cfg80211_leave_ibss(drv, dev);
+	err = cfg80211_leave_ibss(drv, dev, false);
 
 out:
 	cfg80211_put_dev(drv);