fix #537

irc/channelmanager.go

@@ -65,10 +65,17 @@ func (cm *ChannelManager) Join(client *Client, name string, key string, isSajoin
 		return errNoSuchChannel
 	}
 
+	channel := func() *Channel {
 		cm.Lock()
+		defer cm.Unlock()
+
 		entry := cm.chans[casefoldedName]
 		if entry == nil {
 			registered := cm.registeredChannels[casefoldedName]
+			// enforce OpOnlyCreation
+			if !registered && server.Config().Channels.OpOnlyCreation && !client.HasRoleCapabs("chanreg") {
+				return nil
+			}
 			entry = &channelManagerEntry{
 				channel:      NewChannel(server, name, registered),
 				pendingJoins: 0,
@@ -76,8 +83,12 @@ func (cm *ChannelManager) Join(client *Client, name string, key string, isSajoin
 			cm.chans[casefoldedName] = entry
 		}
 		entry.pendingJoins += 1
-	channel := entry.channel
-	cm.Unlock()
+		return entry.channel
+	}()
+
+	if channel == nil {
+		return errNoSuchChannel
+	}
 
 	channel.EnsureLoaded()
 	channel.Join(client, key, isSajoin, rb)

irc/config.go

@@ -321,6 +321,7 @@ type Config struct {
 		DefaultModes         *string `yaml:"default-modes"`
 		defaultModes         modes.Modes
 		MaxChannelsPerClient int  `yaml:"max-channels-per-client"`
+		OpOnlyCreation       bool `yaml:"operator-only-creation"`
 		Registration         ChannelRegistrationConfig
 	}
 

oragono.yaml

@@ -368,6 +368,10 @@ channels:
     # how many channels can a client be in at once?
     max-channels-per-client: 100
 
+    # if this is true, new channels can only be created by operators with the
+    # `chanreg` operator capability
+    operator-only-creation: false
+
     # channel registration - requires an account
     registration:
         # can users register new channels?