Require presence of topics in UNSUBSCRIBE

Wiebe Cazemier
1 parent c4df7557
Showing 1 changed file with 10 additions and 0 deletions
mqttpacket.cpp
@@ -494,8 +494,12 @@ void MqttPacket::handleUnsubscribe()
         throw ProtocolError("Packet ID 0 when unsubscribing is invalid."); // [MQTT-2.3.1-1]
     }
  
+    int numberOfUnsubs = 0;
+
     while (remainingAfterPos() > 0)
     {
+        numberOfUnsubs++;
+
         uint16_t topicLength = readTwoBytesToUInt16();
         std::string topic(readBytes(topicLength), topicLength);
  
@@ -506,6 +510,12 @@ void MqttPacket::handleUnsubscribe()
         logger->logf(LOG_UNSUBSCRIBE, "Client '%s' unsubscribed from '%s'", sender->repr().c_str(), topic.c_str());
     }
  
+    // MQTT-3.10.3-2
+    if (numberOfUnsubs == 0)
+    {
+        throw ProtocolError("No topics specified to unsubscribe to.");
+    }
+
     UnsubAck unsubAck(packet_id);
     MqttPacket response(unsubAck);
     sender->writeMqttPacket(response);