disallow /SAMODE nick +o

irc/handlers.go

@@ -1602,7 +1602,7 @@ func umodeHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *Res
 		}
 
 		// apply mode changes
-		applied = ApplyUserModeChanges(target, changes, msg.Command == "SAMODE")
+		applied = ApplyUserModeChanges(target, changes, msg.Command == "SAMODE", nil)
 	}
 
 	if len(applied) > 0 {
@@ -2117,7 +2117,7 @@ func applyOper(client *Client, oper *Oper, rb *ResponseBuffer) {
 			Op:   modes.Add,
 		}
 		copy(modeChanges[1:], oper.Modes)
-		applied := ApplyUserModeChanges(client, modeChanges, true)
+		applied := ApplyUserModeChanges(client, modeChanges, true, oper)
 
 		client.server.snomasks.Send(sno.LocalOpers, fmt.Sprintf(ircfmt.Unescape("Client opered up $c[grey][$r%s$c[grey], $r%s$c[grey]]"), newDetails.nickMask, oper.Name))
 

irc/modes.go

@@ -23,7 +23,9 @@ var (
 )
 
 // ApplyUserModeChanges applies the given changes, and returns the applied changes.
-func ApplyUserModeChanges(client *Client, changes modes.ModeChanges, force bool) modes.ModeChanges {
+// `oper` is the operclass of the client gaining +o, when applicable (this is just
+// to confirm that the client actually has a valid operclass)
+func ApplyUserModeChanges(client *Client, changes modes.ModeChanges, force bool, oper *Oper) modes.ModeChanges {
 	applied := make(modes.ModeChanges, 0)
 
 	for _, change := range changes {
@@ -31,7 +33,7 @@ func ApplyUserModeChanges(client *Client, changes modes.ModeChanges, force bool)
 		case modes.Bot, modes.Invisible, modes.WallOps, modes.UserRoleplaying, modes.Operator, modes.LocalOperator, modes.RegisteredOnly:
 			switch change.Op {
 			case modes.Add:
-				if !force && (change.Mode == modes.Operator || change.Mode == modes.LocalOperator) {
+				if (change.Mode == modes.Operator || change.Mode == modes.LocalOperator) && !(force && oper != nil) {
 					continue
 				}