From 4e9abd41c0680cef72b034d942f5f9f11e947382 Mon Sep 17 00:00:00 2001
From: Jan Eggers <jan.eggers.ferag@hotmail.com>
Date: Mon, 25 Jun 2018 12:31:19 +0200
Subject: [PATCH] improve error messages

---
 Source/MQTTnet/Serializer/MqttPacketBodyReader.cs | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/Source/MQTTnet/Serializer/MqttPacketBodyReader.cs b/Source/MQTTnet/Serializer/MqttPacketBodyReader.cs
index d751c688..2cf37dd4 100644
--- a/Source/MQTTnet/Serializer/MqttPacketBodyReader.cs
+++ b/Source/MQTTnet/Serializer/MqttPacketBodyReader.cs
@@ -20,6 +20,7 @@ namespace MQTTnet.Serializer
 
         public byte ReadByte()
         {
+            ValidateReceiveBuffer(1);
             return _buffer[_offset++];
         }
 
@@ -30,6 +31,8 @@ namespace MQTTnet.Serializer
 
         public ushort ReadUInt16()
         {
+            ValidateReceiveBuffer(2);
+
             var msb = _buffer[_offset++];
             var lsb = _buffer[_offset++];
             
@@ -40,12 +43,22 @@ namespace MQTTnet.Serializer
         {
             var length = ReadUInt16();
 
+            ValidateReceiveBuffer(length);
+
             var result = new ArraySegment<byte>(_buffer, _offset, length);
             _offset += length;
 
             return result;
         }
 
+        private void ValidateReceiveBuffer(ushort length)
+        {
+            if (_buffer.Length < _offset + length)
+            {
+                throw new ArgumentOutOfRangeException(nameof(_buffer), $"expected at least {_offset + length} bytes but there are only {_buffer.Length} bytes");
+            }
+        }
+
         public string ReadStringWithLengthPrefix()
         {
             var buffer = ReadWithLengthPrefix();