feat: fix objectClass filter will return empty response (#4011)

ldap/server.go

@@ -149,10 +149,6 @@ func handleSearch(w ldap.ResponseWriter, m *ldap.Message) {
 	}
 
 	r := m.GetSearchRequest()
-	if r.FilterString() == "(objectClass=*)" {
-		w.Write(res)
-		return
-	}
 
 	// Handle Stop Signal (server stop / client disconnected / Abandoned request....)
 	select {

ldap/util.go

@@ -200,6 +200,9 @@ func buildUserFilterCondition(filter interface{}) (builder.Cond, error) {
 		}
 		return builder.Eq{field: string(f.AssertionValue())}, nil
 	case message.FilterPresent:
+		if strings.EqualFold(string(f), "objectclass") {
+			return builder.Expr("1 = 1"), nil
+		}
 		field, err := getUserFieldFromAttribute(string(f))
 		if err != nil {
 			return nil, err