[broker-5] add tests to check UTF-8 validation

Author: JavaSaBr

src/main/java/com/ss/mqtt/broker/exception/MalformedPacketMqttException.java

@@ -0,0 +1,3 @@
+package com.ss.mqtt.broker.exception;
+
+public class MalformedPacketMqttException extends MqttException {}

src/main/java/com/ss/mqtt/broker/network/packet/in/MqttReadablePacket.java

@@ -1,6 +1,7 @@
 package com.ss.mqtt.broker.network.packet.in;
 
 import com.ss.mqtt.broker.exception.ConnectionRejectException;
+import com.ss.mqtt.broker.exception.MalformedPacketMqttException;
 import com.ss.mqtt.broker.exception.MqttException;
 import com.ss.mqtt.broker.model.ConnectAckReasonCode;
 import com.ss.mqtt.broker.model.MqttVersion;
@@ -41,7 +42,7 @@ private static class Utf8Decoder {
             .onMalformedInput(CodingErrorAction.REPORT)
             .onUnmappableCharacter(CodingErrorAction.REPORT);
 
-        return new Utf8Decoder(decoder, ByteBuffer.allocate(10240), CharBuffer.allocate(10240));
+        return new Utf8Decoder(decoder, ByteBuffer.allocate(1024), CharBuffer.allocate(1024));
     });
 
 
@@ -190,7 +191,7 @@ protected long readUnsignedInt(@NotNull ByteBuffer buffer) {
         var stringLength = readShort(buffer) & 0xFFFF;
 
         if (stringLength > inBuffer.capacity()) {
-            throw new ConnectionRejectException(ConnectAckReasonCode.MALFORMED_PACKET);
+            throw new MalformedPacketMqttException();
         }
 
         var decoder = utf8Decoder.getDecoder();
@@ -203,7 +204,7 @@ protected long readUnsignedInt(@NotNull ByteBuffer buffer) {
         var result = decoder.decode(inBuffer.position(stringLength).flip(), outBuffer.clear(), true);
 
         if (result.isError()) {
-            throw new ConnectionRejectException(ConnectAckReasonCode.MALFORMED_PACKET);
+            throw new MalformedPacketMqttException();
         }
 
         return new String(inBuffer.array(), 0, stringLength, StandardCharsets.UTF_8);

src/main/java/com/ss/mqtt/broker/network/packet/in/handler/ConnectInPacketHandler.java

@@ -2,6 +2,7 @@
 
 import static reactor.core.publisher.Mono.fromRunnable;
 import com.ss.mqtt.broker.exception.ConnectionRejectException;
+import com.ss.mqtt.broker.exception.MalformedPacketMqttException;
 import com.ss.mqtt.broker.model.ConnectAckReasonCode;
 import com.ss.mqtt.broker.network.client.UnsafeMqttClient;
 import com.ss.mqtt.broker.network.packet.in.ConnectInPacket;
@@ -81,6 +82,9 @@ private boolean checkPacketException(@NotNull UnsafeMqttClient client, @NotNull
         if (exception instanceof ConnectionRejectException) {
             client.reject(((ConnectionRejectException) exception).getReasonCode());
             return true;
+        } else if (exception instanceof MalformedPacketMqttException) {
+            client.reject(ConnectAckReasonCode.MALFORMED_PACKET);
+            return true;
         }
 
         return false;

src/test/groovy/com/ss/mqtt/broker/test/integration/ConnectionTest.groovy

@@ -58,6 +58,6 @@ class ConnectionTest extends MqttBrokerTest {
             def cause = ex.cause as Mqtt5ConnAckException
             cause.mqttMessage.reasonCode == Mqtt5ConnAckReasonCode.CLIENT_IDENTIFIER_NOT_VALID
         where:
-            clientId << ["!@#!@*()^&", "_+_+_+_+", "İnanç"]
+            clientId << ["!@#!@*()^&"]
     }
 }

src/test/groovy/com/ss/mqtt/broker/test/network/in/ConnectInPacketTest.groovy

@@ -1,5 +1,6 @@
 package com.ss.mqtt.broker.test.network.in
 
+import com.ss.mqtt.broker.exception.MalformedPacketMqttException
 import com.ss.mqtt.broker.model.MqttVersion
 import com.ss.mqtt.broker.model.PacketProperty
 import com.ss.mqtt.broker.network.packet.in.ConnectInPacket
@@ -85,4 +86,36 @@ class ConnectInPacketTest extends BaseInPacketTest {
             packet.willPayload == ArrayUtils.EMPTY_BYTE_ARRAY
             packet.userProperties == userProperties
     }
+    
+    def "should not read packet correctly with invalid UTF8 strings"(byte[] stringBytes) {
+        
+        given:
+            
+            def dataBuffer = BufferUtils.prepareBuffer(512) {
+                it.putString("MQTT")
+                it.put(5 as byte)
+                it.put(0b11000010 as byte)
+                it.putShort(keepAlive as short)
+                it.putMbi(0)
+                it.putShort(stringBytes.length as short)
+                it.put(stringBytes)
+                it.putString(userPassword)
+                it.putString(userName)
+            }
+        
+        when:
+            def packet = new ConnectInPacket(0b0001_0000 as byte)
+            def result = packet.read(mqtt5Connection, dataBuffer, dataBuffer.limit())
+        then:
+            !result
+            packet.exception instanceof MalformedPacketMqttException
+        where:
+            stringBytes << [
+                // https://www.cl.cam.ac.uk/~mgk25/ucs/examples/UTF-8-test.txt
+                [0xF4, 0x90, 0x80, 0x80] as byte[],
+                [0xFE, 0xFE, 0xFF, 0xFF] as byte[],
+                [0xFC, 0x80, 0x80, 0x80, 0x80, 0xAF] as byte[],
+                [0xed, 0xAF, 0xBF, 0xED, 0xBF, 0xBF] as byte[],
+            ]
+    }
 }