Validate fixed header bits in MQTT (#11389)
Motivation: The MQTT spec states that the bits in the fixed header must be set to specific values depending on message type. If a client sends a message with the wrong bits, the server must treat the message as malformed. Netty did not check the value of the reserved bits in the fixed header. See: MQTT3.1.1: http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/errata01/os/mqtt-v3.1.1-errata01-os-complete.html#_Toc442180835 MQTT 5.0: https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901023 Modification: Add validation checks to MqttDecoder.java Add unit tests to MqttCodecTest.java Fixed two instances where messages were generated for other unit tests with an incorrect fixed header. Result: Fixes #11379.
This commit is contained in:
Hylke van der Schaaf
GitHub
parent
0d5774a82b
commit
2f4f7135fb
@ -153,7 +153,11 @@ public final class MqttDecoder extends ReplayingDecoder<DecoderState> {
|
||||
}
|
||||
|
||||
/**
|
||||
* Decodes the fixed header. It's one byte for the flags and then variable bytes for the remaining length.
|
||||
* Decodes the fixed header. It's one byte for the flags and then variable
|
||||
* bytes for the remaining length.
|
||||
*
|
||||
* @see
|
||||
* https://docs.oasis-open.org/mqtt/mqtt/v3.1.1/errata01/os/mqtt-v3.1.1-errata01-os-complete.html#_Toc442180841
|
||||
*
|
||||
* @param buffer the buffer to decode from
|
||||
* @return the fixed header
|
||||
@ -166,6 +170,59 @@ public final class MqttDecoder extends ReplayingDecoder<DecoderState> {
|
||||
int qosLevel = (b1 & 0x06) >> 1;
|
||||
boolean retain = (b1 & 0x01) != 0;
|
||||
|
||||
switch (messageType) {
|
||||
case PUBLISH:
|
||||
if (qosLevel == 3) {
|
||||
throw new DecoderException("Illegal QOS Level in fixed header of PUBLISH message ("
|
||||
+ qosLevel + ')');
|
||||
}
|
||||
break;
|
||||
|
||||
case PUBREL:
|
||||
case SUBSCRIBE:
|
||||
case UNSUBSCRIBE:
|
||||
if (dupFlag) {
|
||||
throw new DecoderException("Illegal BIT 3 in fixed header of " + messageType.toString()
|
||||
+ " message, must be 0, found 1");
|
||||
}
|
||||
if (qosLevel != 1) {
|
||||
throw new DecoderException("Illegal QOS Level in fixed header of " + messageType.toString()
|
||||
+ " message, must be 1, found " + qosLevel);
|
||||
}
|
||||
if (retain) {
|
||||
throw new DecoderException("Illegal BIT 0 in fixed header of " + messageType.toString()
|
||||
+ " message, must be 0, found 1");
|
||||
}
|
||||
break;
|
||||
|
||||
case AUTH:
|
||||
case CONNACK:
|
||||
case CONNECT:
|
||||
case DISCONNECT:
|
||||
case PINGREQ:
|
||||
case PINGRESP:
|
||||
case PUBACK:
|
||||
case PUBCOMP:
|
||||
case PUBREC:
|
||||
case SUBACK:
|
||||
case UNSUBACK:
|
||||
if (dupFlag) {
|
||||
throw new DecoderException("Illegal BIT 3 in fixed header of " + messageType.toString()
|
||||
+ " message, must be 0, found 1");
|
||||
}
|
||||
if (qosLevel != 0) {
|
||||
throw new DecoderException("Illegal BIT 2 or 1 in fixed header of " + messageType.toString()
|
||||
+ " message, must be 0, found " + qosLevel);
|
||||
}
|
||||
if (retain) {
|
||||
throw new DecoderException("Illegal BIT 0 in fixed header of " + messageType.toString()
|
||||
+ " message, must be 0, found 1");
|
||||
}
|
||||
break;
|
||||
default:
|
||||
throw new DecoderException("Unknown message type, do not know how to validate fixed header");
|
||||
}
|
||||
|
||||
int remainingLength = 0;
|
||||
int multiplier = 1;
|
||||
short digit;
|
||||
|
||||
@ -156,6 +156,81 @@ public class MqttCodecTest {
|
||||
assertEquals("non-zero reserved flag", cause.getMessage());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void testConnectMessageNonZeroReservedBit0Mqtt311() throws Exception {
|
||||
final MqttConnectMessage message = createConnectMessage(MqttVersion.MQTT_3_1_1);
|
||||
ByteBuf byteBuf = MqttEncoder.doEncode(ctx, message);
|
||||
byte firstByte = byteBuf.getByte(0);
|
||||
byteBuf.setByte(0, (byte) (firstByte | 1)); // set bit 0 to 1
|
||||
final List<Object> out = new LinkedList<Object>();
|
||||
mqttDecoder.decode(ctx, byteBuf, out);
|
||||
checkForSingleDecoderException(out);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void testConnectMessageNonZeroReservedBit1Mqtt311() throws Exception {
|
||||
final MqttConnectMessage message = createConnectMessage(MqttVersion.MQTT_3_1_1);
|
||||
ByteBuf byteBuf = MqttEncoder.doEncode(ctx, message);
|
||||
byte firstByte = byteBuf.getByte(0);
|
||||
byteBuf.setByte(0, (byte) (firstByte | 2)); // set bit 1 to 1
|
||||
final List<Object> out = new LinkedList<Object>();
|
||||
mqttDecoder.decode(ctx, byteBuf, out);
|
||||
checkForSingleDecoderException(out);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void testConnectMessageNonZeroReservedBit2Mqtt311() throws Exception {
|
||||
final MqttConnectMessage message = createConnectMessage(MqttVersion.MQTT_3_1_1);
|
||||
ByteBuf byteBuf = MqttEncoder.doEncode(ctx, message);
|
||||
byte firstByte = byteBuf.getByte(0);
|
||||
byteBuf.setByte(0, (byte) (firstByte | 4)); // set bit 2 to 1
|
||||
final List<Object> out = new LinkedList<Object>();
|
||||
mqttDecoder.decode(ctx, byteBuf, out);
|
||||
checkForSingleDecoderException(out);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void testConnectMessageNonZeroReservedBit3Mqtt311() throws Exception {
|
||||
final MqttConnectMessage message = createConnectMessage(MqttVersion.MQTT_3_1_1);
|
||||
ByteBuf byteBuf = MqttEncoder.doEncode(ctx, message);
|
||||
byte firstByte = byteBuf.getByte(0);
|
||||
byteBuf.setByte(0, (byte) (firstByte | 8)); // set bit 3 to 1
|
||||
final List<Object> out = new LinkedList<Object>();
|
||||
mqttDecoder.decode(ctx, byteBuf, out);
|
||||
checkForSingleDecoderException(out);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void testSubscribeMessageNonZeroReservedBit0Mqtt311() throws Exception {
|
||||
final MqttSubscribeMessage message = createSubscribeMessage();
|
||||
ByteBuf byteBuf = MqttEncoder.doEncode(ctx, message);
|
||||
byte firstByte = byteBuf.getByte(0);
|
||||
byteBuf.setByte(0, (byte) (firstByte | 1)); // set bit 1 to 0
|
||||
final List<Object> out = new LinkedList<Object>();
|
||||
mqttDecoder.decode(ctx, byteBuf, out);
|
||||
checkForSingleDecoderException(out);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void testSubscribeMessageZeroReservedBit1Mqtt311() throws Exception {
|
||||
final MqttSubscribeMessage message = createSubscribeMessage();
|
||||
ByteBuf byteBuf = MqttEncoder.doEncode(ctx, message);
|
||||
byte firstByte = byteBuf.getByte(0);
|
||||
byteBuf.setByte(0, (byte) (firstByte & ~2)); // set bit 1 to 0
|
||||
final List<Object> out = new LinkedList<Object>();
|
||||
mqttDecoder.decode(ctx, byteBuf, out);
|
||||
checkForSingleDecoderException(out);
|
||||
}
|
||||
|
||||
private void checkForSingleDecoderException(final List<Object> out) {
|
||||
assertEquals("Expected one object but got " + out.size(), 1, out.size());
|
||||
assertFalse("Message should not be an MqttConnectMessage",
|
||||
MqttConnectMessage.class.isAssignableFrom(out.get(0).getClass()));
|
||||
MqttMessage result = (MqttMessage) out.get(0);
|
||||
assertTrue("Decoding should have resulted in a DecoderException",
|
||||
result.decoderResult().cause() instanceof DecoderException);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void testConnectMessageNoPassword() throws Exception {
|
||||
final MqttConnectMessage message = createConnectMessage(
|
||||
@ -867,7 +942,7 @@ public class MqttCodecTest {
|
||||
|
||||
private static MqttSubscribeMessage createSubscribeMessage() {
|
||||
MqttFixedHeader mqttFixedHeader =
|
||||
new MqttFixedHeader(MqttMessageType.SUBSCRIBE, false, MqttQoS.AT_LEAST_ONCE, true, 0);
|
||||
new MqttFixedHeader(MqttMessageType.SUBSCRIBE, false, MqttQoS.AT_LEAST_ONCE, false, 0);
|
||||
MqttMessageIdVariableHeader mqttMessageIdVariableHeader = MqttMessageIdVariableHeader.from(12345);
|
||||
|
||||
List<MqttTopicSubscription> topicSubscriptions = new LinkedList<MqttTopicSubscription>();
|
||||
@ -893,7 +968,7 @@ public class MqttCodecTest {
|
||||
|
||||
private static MqttUnsubscribeMessage createUnsubscribeMessage() {
|
||||
MqttFixedHeader mqttFixedHeader =
|
||||
new MqttFixedHeader(MqttMessageType.UNSUBSCRIBE, false, MqttQoS.AT_LEAST_ONCE, true, 0);
|
||||
new MqttFixedHeader(MqttMessageType.UNSUBSCRIBE, false, MqttQoS.AT_LEAST_ONCE, false, 0);
|
||||
MqttMessageIdVariableHeader mqttMessageIdVariableHeader = MqttMessageIdVariableHeader.from(12345);
|
||||
|
||||
List<String> topics = new LinkedList<String>();
|
||||
|
||||
Loading…
Reference in New Issue
Block a user