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Close connection on protocol violation

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According to the standard's section "4.8 Handling errors" the client
must close the current connection if it encounters a protocol violation.

Change-Id: I0be8fb381d42e7d90dd871d3a959fce9d478ea65
Reviewed-by: Maurice Kalinowski <maurice.kalinowski@qt.io>
This commit is contained in:
Lorenz Haas 2017-10-18 20:17:17 +02:00
parent ea0d792a44
commit dcbadaddea
3 changed files with 72 additions and 18 deletions
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1
src/mqtt/qmqttclient.h
View File

@ -65,6 +65,7 @@ public:
NotAuthorized = 5,
// Qt states
TransportInvalid = 256,
ProtocolViolation,
UnknownError
};
enum ProtocolVersion {

88
src/mqtt/qmqttconnection.cpp
View File

@ -496,6 +496,17 @@ void QMqttConnection::readBuffer(char *data, qint64 size)
m_readBuffer = m_readBuffer.mid(size);
}
void QMqttConnection::closeConnection(QMqttClient::ClientError error)
{
m_readBuffer.clear();
m_pingTimer.stop();
m_activeSubscriptions.clear();
m_internalState = BrokerDisconnected;
m_transport->disconnect();
m_transport->close();
m_clientPrivate->setStateAndError(QMqttClient::Disconnected, error);
}
QByteArray QMqttConnection::readBuffer(qint64 size)
{
QByteArray res = m_readBuffer.left(size);
@ -510,7 +521,7 @@ void QMqttConnection::finalize_connack()
readBuffer((char*)&ackFlags, 1);
if (ackFlags > 1) { // MQTT-3.2.2.1
qWarning("Unexpected CONNACK Flags set");
// ## SET SOME ERROR
closeConnection(QMqttClient::ProtocolViolation);
return;
}
bool sessionPresent = ackFlags == 1;
@ -694,8 +705,11 @@ void QMqttConnection::finalize_pingresp()
qCDebug(lcMqttConnectionVerbose) << "Finalize PINGRESP";
quint8 v;
readBuffer((char*)&v, 1);
if (v != 0)
if (v != 0) {
qWarning("Received a PINGRESP with payload!");
closeConnection(QMqttClient::ProtocolViolation);
return;
}
emit m_client->pingResponseReceived();
}
@ -726,13 +740,13 @@ void QMqttConnection::processData()
case QMqttControlPacket::PINGRESP:
finalize_pingresp();
break;
case QMqttControlPacket::PUBREL: {
case QMqttControlPacket::PUBREL:
finalize_pubrel();
break;
}
default:
qFatal("Unknown packet to finalize");
break;
qWarning("Unknown packet to finalize");
closeConnection(QMqttClient::ProtocolViolation);
return;
}
m_missingData = 0;
}
@ -754,15 +768,16 @@ void QMqttConnection::processData()
qCDebug(lcMqttConnectionVerbose) << "Received CONNACK";
if (m_internalState != BrokerWaitForConnectAck) {
qWarning("Received CONNACK at unexpected time!");
break;
closeConnection(QMqttClient::ProtocolViolation);
return;
}
quint8 payloadSize;
readBuffer((char*)&payloadSize, 1);
if (payloadSize != 2) {
qWarning("Unexpected FRAME size in CONNACK");
// ## SET SOME ERROR
break;
closeConnection(QMqttClient::ProtocolViolation);
return;
}
m_missingData = 2;
break;
@ -779,6 +794,12 @@ void QMqttConnection::processData()
m_currentPublish.dup = m_currentPacket & 0x08;
m_currentPublish.qos = (m_currentPacket & 0x06) >> 1;
m_currentPublish.retain = m_currentPacket & 0x01;
if ((m_currentPublish.qos == 0 && m_currentPublish.dup != 0)
|| m_currentPublish.qos > 2) {
closeConnection(QMqttClient::ProtocolViolation);
return;
}
// remaining length
quint32 multiplier = 1;
quint32 msgLength = 0;
@ -789,8 +810,11 @@ void QMqttConnection::processData()
msgLength += (b & 127) * multiplier;
multiplier *= 128;
iteration++;
if (iteration > 4)
qFatal("Publish message is too big to handle");
if (iteration > 4) {
qWarning("Publish message is too big to handle");
closeConnection(QMqttClient::ProtocolViolation);
return;
}
} while ((b & 128) != 0);
m_missingData = msgLength;
break;
@ -799,22 +823,50 @@ void QMqttConnection::processData()
qCDebug(lcMqttConnectionVerbose) << "Received PINGRESP";
m_missingData = 1;
break;
case QMqttControlPacket::PUBREL: {
qCDebug(lcMqttConnectionVerbose) << "Received PUBREL";
char remaining;
readBuffer(&remaining, 1);
if (remaining != 0x02) {
qWarning("Received 2 byte message with invalid remaining length");
closeConnection(QMqttClient::ProtocolViolation);
return;
}
if ((m_currentPacket & 0x0F) != 0x02) {
qWarning("Malformed fixed header for PUBREL");
closeConnection(QMqttClient::ProtocolViolation);
return;
}
m_missingData = 2;
break;
}
case QMqttControlPacket::UNSUBACK:
case QMqttControlPacket::PUBACK:
case QMqttControlPacket::PUBREC:
case QMqttControlPacket::PUBCOMP:
case QMqttControlPacket::PUBREL: {
qCDebug(lcMqttConnectionVerbose) << "Received UNSUBACK/PUBACK/PUBREC/PUBCOMP/PUBREL";
case QMqttControlPacket::PUBCOMP: {
qCDebug(lcMqttConnectionVerbose) << "Received UNSUBACK/PUBACK/PUBREC/PUBCOMP";
if ((m_currentPacket & 0x0F) != 0) {
qWarning("Malformed fixed header");
closeConnection(QMqttClient::ProtocolViolation);
return;
}
char remaining;
readBuffer(&remaining, 1); // ### TODO: verify this is 2
if (remaining != 0x02)
readBuffer(&remaining, 1);
if (remaining != 0x02) {
qWarning("Received 2 byte message with invalid remaining length");
closeConnection(QMqttClient::ProtocolViolation);
return;
}
m_missingData = 2;
break;
}
default:
qFatal("Received unknown command");
break;
qWarning("Received unknown command");
closeConnection(QMqttClient::ProtocolViolation);
return;
}
/* set current command CONNACK - PINGRESP */

1
src/mqtt/qmqttconnection_p.h
View File

@ -113,6 +113,7 @@ private:
void finalize_pingresp();
void processData();
void readBuffer(char *data, qint64 size);
void closeConnection(QMqttClient::ClientError error);
QByteArray readBuffer(qint64 size);
QByteArray m_readBuffer;
qint64 m_missingData{0};