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Reject MQTT5 PUBLISH with Topic Alias 0 #326

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Merged
popduke merged 2 commits into from
Nov 5, 2026
Merged

Reject MQTT5 PUBLISH with Topic Alias 0 #326

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911315a
Reject MQTT5 PUBLISH with Topic Alias 0
RaphaelFakhri Nov 3, 2026
70303ce
Merge branch 'main' into fix/mqtt5-reject-topic-alias-zero
popduke Nov 5, 2026
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5 changes: 5 additions & 0 deletions ...omq-mqtt-server/src/main/java/org/apache/bifromq/mqtt/handler/v5/MQTT5ProtocolHelper.java
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Original file line number Diff line number Diff line change
Expand Up @@ -662,6 +662,11 @@ public ProtocolResponse validatePubMessage(MqttPublishMessage message) {
MQTT5MessageBuilders.disconnect().reasonCode(MQTT5DisconnectReasonCode.TopicAliasInvalid).build(),
getLocal(ProtocolViolation.class).statement("MQTT5-3.2.2-17").clientInfo(clientInfo));
}
if (topicAlias.isPresent() && topicAlias.get() == 0) {
return farewell(
MQTT5MessageBuilders.disconnect().reasonCode(MQTT5DisconnectReasonCode.TopicAliasInvalid).build(),
getLocal(ProtocolViolation.class).statement("MQTT5-3.3.2-8").clientInfo(clientInfo));
}
// create or update alias
if (topic.isEmpty()) {
if (topicAlias.isPresent()) {
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18 changes: 18 additions & 0 deletions ...-server/src/test/java/org/apache/bifromq/mqtt/handler/v5/TransientSessionHandlerTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -515,6 +515,24 @@ public void c2sPubAlias() {
assertEquals(((MqttMessageIdVariableHeader) ackMessage.variableHeader()).messageId(), 124);
}

@Test
public void c2sPubWithZeroTopicAlias() {
mockCheckPermission(true);
mockDistDist(true);
assertTrue(channel.isOpen());
channel.writeInbound(MQTTMessageUtils.publishMQTT5QoS1Message(topic, 123, 0));
channel.advanceTimeBy(6, TimeUnit.SECONDS);
channel.runPendingTasks();
channel.flushOutbound();
MqttMessage disconnMessage = channel.readOutbound();
assertEquals(disconnMessage.fixedHeader().messageType(), DISCONNECT);
assertEquals(((MqttReasonCodeAndPropertiesVariableHeader) disconnMessage.variableHeader()).reasonCode(),
MQTT5DisconnectReasonCode.TopicAliasInvalid.value());
assertFalse(channel.isActive());
verify(distClient, never()).pub(anyLong(), anyString(), any(Message.class), any(ClientInfo.class));
verifyEvent(MQTT_SESSION_START, PROTOCOL_VIOLATION, MQTT_SESSION_STOP);
}

@Test
public void handleQoS0Pub() {
mockCheckPermission(true);
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