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Validate MQTT CONNECT reserved flag in variable header

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Motivation:

According to the MQTT 3.1.1 Protocol Specification: The Server MUST validate that the reserved flag in the CONNECT Control Packet is set to zero and disconnect the Client if it is not zero. (http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc385349230)

Resolves #4182

Modifications:

Check the CONNECT reserved flag for MQTT 3.1.1. If it's not 0, throw an exception.

Result:

If the CONNECT reserved flag, a decode failure will be emitted.
This commit is contained in:
Xiaoyan Lin 2016-03-15 22:25:39 -07:00 committed by Norman Maurer
parent 6e840d8e62
commit abbdc70d8b
2 changed files with 32 additions and 0 deletions
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9
codec-mqtt/src/main/java/io/netty/handler/codec/mqtt/MqttDecoder.java
View File

@ -221,6 +221,15 @@ public class MqttDecoder extends ReplayingDecoder<DecoderState> {
final int willQos = (b1 & 0x18) >> 3;
final boolean willFlag = (b1 & 0x04) == 0x04;
final boolean cleanSession = (b1 & 0x02) == 0x02;
if (mqttVersion == MqttVersion.MQTT_3_1_1) {
final boolean zeroReservedFlag = (b1 & 0x01) == 0x0;
if (!zeroReservedFlag) {
// MQTT v3.1.1: The Server MUST validate that the reserved flag in the CONNECT Control Packet is
// set to zero and disconnect the Client if it is not zero.
// See http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc385349230
throw new DecoderException("non-zero reserved flag");
}
}
final MqttConnectVariableHeader mqttConnectVariableHeader = new MqttConnectVariableHeader(
mqttVersion.protocolName(),

23
codec-mqtt/src/test/java/io/netty/handler/codec/mqtt/MqttCodecTest.java
View File

@ -21,6 +21,7 @@ import io.netty.buffer.ByteBufAllocator;
import io.netty.buffer.UnpooledByteBufAllocator;
import io.netty.channel.Channel;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.DecoderException;
import io.netty.util.CharsetUtil;
import org.easymock.Mock;
import org.junit.Before;
@ -96,6 +97,28 @@ public class MqttCodecTest {
validateConnectPayload(message.payload(), decodedMessage.payload());
}
@Test
public void testConnectMessageWithNonZeroReservedFlagForMqtt311() throws Exception {
final MqttConnectMessage message = createConnectMessage(MqttVersion.MQTT_3_1_1);
ByteBuf byteBuf = MqttEncoder.doEncode(ALLOCATOR, message);
try {
// Set the reserved flag in the CONNECT Packet to 1
byteBuf.setByte(9, byteBuf.getByte(9) | 0x1);
final List<Object> out = new LinkedList<Object>();
mqttDecoder.decode(ctx, byteBuf, out);
assertEquals("Expected one object bout got " + out.size(), 1, out.size());
final MqttMessage decodedMessage = (MqttMessage) out.get(0);
assertTrue(decodedMessage.decoderResult().isFailure());
Throwable cause = decodedMessage.decoderResult().cause();
assertTrue(cause instanceof DecoderException);
assertEquals("non-zero reserved flag", cause.getMessage());
} finally {
byteBuf.release();
}
}
@Test
public void testConnAckMessage() throws Exception {
final MqttConnAckMessage message = createConnAckMessage();