cfg80211: correctly check ad-hoc channels

Ad-hoc requires beaconing for regulatory purposes. Validate that the
channel is valid for beaconing, and not only enabled.
Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Reviewed-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/reg.c

@@ -1546,12 +1546,18 @@ static bool reg_wdev_chan_valid(struct wiphy *wiphy, struct wireless_dev *wdev)
 		if (!wdev->beacon_interval)
 			goto out;
 
+		ret = cfg80211_reg_can_beacon(wiphy,
+					      &wdev->chandef, wdev->iftype);
+		break;
+	case NL80211_IFTYPE_ADHOC:
+		if (!wdev->ssid_len)
+			goto out;
+
 		ret = cfg80211_reg_can_beacon(wiphy,
 					      &wdev->chandef, wdev->iftype);
 		break;
 	case NL80211_IFTYPE_STATION:
 	case NL80211_IFTYPE_P2P_CLIENT:
-	case NL80211_IFTYPE_ADHOC:
 		if (!wdev->current_bss ||
 		    !wdev->current_bss->pub.channel)
 			goto out;