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cshannon pushed a commit to branch activemq-6.3.x
in repository https://gitbox.apache.org/repos/asf/activemq.git
The following commit(s) were added to refs/heads/activemq-6.3.x by this push:
new eb5bd11ab0 fix: MQTTWireFormat rejecting valid 4-byte remaining
lengths (#2517) (#2521)
eb5bd11ab0 is described below
commit eb5bd11ab0f322c689f02638fa2d55a30d1df339
Author: Christopher L. Shannon <[email protected]>
AuthorDate: Fri Sep 4 10:47:38 2026 -0400
fix: MQTTWireFormat rejecting valid 4-byte remaining lengths (#2517) (#2521)
Fix MQTTWireFormat rejecting valid 4-byte remaining lengths
(cherry picked from commit 15a182dca5eee5b9370f74a324e6220256530cb4)
Co-authored-by: Hailey <[email protected]>
---
.../activemq/transport/mqtt/MQTTWireFormat.java | 4 +-
.../activemq/transport/mqtt/MQTTCodecTest.java | 53 ++++++++++++++++++++++
2 files changed, 55 insertions(+), 2 deletions(-)
diff --git
a/activemq-mqtt/src/main/java/org/apache/activemq/transport/mqtt/MQTTWireFormat.java
b/activemq-mqtt/src/main/java/org/apache/activemq/transport/mqtt/MQTTWireFormat.java
index 9e79fd25f4..ff00c6c923 100644
---
a/activemq-mqtt/src/main/java/org/apache/activemq/transport/mqtt/MQTTWireFormat.java
+++
b/activemq-mqtt/src/main/java/org/apache/activemq/transport/mqtt/MQTTWireFormat.java
@@ -92,12 +92,12 @@ public class MQTTWireFormat implements WireFormat {
int length = 0;
do {
digit = dataIn.readByte();
- length += (digit & 0x7F) * multiplier;
- multiplier <<= 7;
// MQTT protocol limits Remaining Length to 4 bytes
if (multiplier == MAX_MULTIPLIER && (digit & 128) != 0) {
throw new IOException("Remaining length exceeds 4 bytes");
}
+ length += (digit & 0x7F) * multiplier;
+ multiplier <<= 7;
}
while ((digit & 0x80) != 0);
diff --git
a/activemq-mqtt/src/test/java/org/apache/activemq/transport/mqtt/MQTTCodecTest.java
b/activemq-mqtt/src/test/java/org/apache/activemq/transport/mqtt/MQTTCodecTest.java
index 62f367aa7b..ecee905ca1 100644
---
a/activemq-mqtt/src/test/java/org/apache/activemq/transport/mqtt/MQTTCodecTest.java
+++
b/activemq-mqtt/src/test/java/org/apache/activemq/transport/mqtt/MQTTCodecTest.java
@@ -364,4 +364,57 @@ public class MQTTCodecTest {
}
}
+ @Test
+ public void testCodecAcceptsFourByteRemainingLength() throws Exception {
+ // 2,097,152 is the smallest value that requires a 4-byte Remaining
Length.
+ // Payload size = target RL - variable header overhead (2 topic length
+ topic + 2 packet id)
+ final String topic = "TOPIC";
+ final int overhead = 2 + topic.length() + 2; // topic length field +
topic + message id (QoS 1)
+ final int payloadSize = 2_097_152 - overhead;
+
+ PUBLISH publish = new PUBLISH();
+ publish.qos(QoS.AT_LEAST_ONCE);
+ publish.messageId((short) 1);
+ publish.topicName(new UTF8Buffer(topic));
+ publish.payload(new Buffer(new byte[payloadSize]));
+
+ Buffer marshalled;
+ try (DataByteArrayOutputStream output = new
DataByteArrayOutputStream()) {
+ wireFormat.marshal(publish.encode(), output);
+ marshalled = output.toBuffer();
+ }
+
+ try (DataByteArrayInputStream input = new
DataByteArrayInputStream(marshalled)) {
+ codec.parse(input, marshalled.length());
+ }
+
+ assertEquals("Expected one frame from a valid 4-byte Remaining
Length", 1, frames.size());
+ PUBLISH decoded = new PUBLISH().decode(frames.get(0));
+ assertEquals(payloadSize, decoded.payload().length());
+ }
+
+ @Test
+ public void testUnmarshalAcceptsFourByteRemainingLength() throws Exception
{
+ final String topic = "TOPIC";
+ final int overhead = 2 + topic.length() + 2;
+ final int payloadSize = 2_097_152 - overhead;
+
+ PUBLISH publish = new PUBLISH();
+ publish.qos(QoS.AT_LEAST_ONCE);
+ publish.messageId((short) 1);
+ publish.topicName(new UTF8Buffer(topic));
+ publish.payload(new Buffer(new byte[payloadSize]));
+
+ Buffer marshalled;
+ try (DataByteArrayOutputStream output = new
DataByteArrayOutputStream()) {
+ wireFormat.marshal(publish.encode(), output);
+ marshalled = output.toBuffer();
+ }
+
+ MQTTFrame frame = (MQTTFrame) wireFormat.unmarshal(
+ new ByteSequence(marshalled.data, marshalled.offset,
marshalled.length));
+ PUBLISH decoded = new PUBLISH().decode(frame);
+ assertEquals(payloadSize, decoded.payload().length());
+ }
+
}
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