From c4df7557eeb827b35965780a7ebd682a720d4a5e Mon Sep 17 00:00:00 2001
From: Wiebe Cazemier <wiebe@halfgaar.net>
Date: Sat, 9 Oct 2021 14:47:43 +0200
Subject: [PATCH] Require topics to be present in subscribe packet

---
 mqttpacket.cpp | 6 ++++++
 1 file changed, 6 insertions(+), 0 deletions(-)

diff --git a/mqttpacket.cpp b/mqttpacket.cpp
index 055b1cd..70b2192 100644
--- a/mqttpacket.cpp
+++ b/mqttpacket.cpp
@@ -468,6 +468,12 @@ void MqttPacket::handleSubscribe()
         }
     }
 
+    // MQTT-3.8.3-3
+    if (subs_reponse_codes.empty())
+    {
+        throw ProtocolError("No topics specified to subscribe to.");
+    }
+
     SubAck subAck(packet_id, subs_reponse_codes);
     MqttPacket response(subAck);
     sender->writeMqttPacket(response);
--
libgit2 0.21.4