[AMQ-4986] tightEncoding=false + failover triggers Broker memory exhaust

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Cannot Reproduce
• Affects Version/s: 5.6.0, 5.7.0, 5.8.0, 5.9.0
• Component/s: Broker

Environment

java 1.7
Client library 5.5.1

• Assignee: Unassigned
• Reporter: Felix Ehm
• Created: 22/Jan/14 11:34
• Updated: 21/Apr/16 19:34
• Resolved: 21/Apr/16 19:34

Description

We experience this problem in combination with 5.5.1 client and the wireformat.tightEncodingEnabled=false+ failover:

Scenario:
1. start standard broker
2. start Client (with e.g. a MessageListener) with failover protocol: e.g. failover:(tcp://123.123.123.123:61616?wireformat.tightEncodingEnabled=false)
3. wait around 30sec (default for inactivity check)

Result:
The client closes the connection and re-tries to the broker which in turn throws the following exception:

2014-01-21 20:12:49,568 [ActiveMQ Transport: tcp:///123.123.123.123:60156@61616] DEBUG Transport  Transport Connection to: tcp://124.124.124.124:60156 failed: java.io.IOException: Unexpected error occured: java.lang.OutOfMemoryError: Java heap space
java.io.IOException: Unexpected error occured: java.lang.OutOfMemoryError: Java heap space
	at org.apache.activemq.transport.tcp.TcpTransport.run(TcpTransport.java:203)
	at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.OutOfMemoryError: Java heap space
	at org.apache.activemq.openwire.v8.BaseDataStreamMarshaller.looseUnmarshalByteSequence(BaseDataStreamMarshaller.java:638)
	at org.apache.activemq.openwire.v8.WireFormatInfoMarshaller.looseUnmarshal(WireFormatInfoMarshaller.java:132)
	at org.apache.activemq.openwire.OpenWireFormat.doUnmarshal(OpenWireFormat.java:373)
	at org.apache.activemq.openwire.OpenWireFormat.unmarshal(OpenWireFormat.java:285)
	at org.apache.activemq.transport.tcp.TcpTransport.readCommand(TcpTransport.java:221)
	at org.apache.activemq.transport.tcp.TcpTransport.doRun(TcpTransport.java:213)
	at org.apache.activemq.transport.tcp.TcpTransport.run(TcpTransport.java:196)
	... 1 more

The problem here is that the BaseDataStreamMarshaller reads an int from the buffer and re-uses it immediately to allocate a byte array:

protected byte[] looseUnmarshalByteArray(DataInput dataIn) throws IOException {
        byte rc[] = null;
        if (dataIn.readBoolean()) {
            int size = dataIn.readInt();
            rc = new byte[size];   // PROBLEM! What happens if size has been read and interpreted wrongly ? 
            dataIn.readFully(rc);
        }
        return rc;
    }

In our case the dadaIn.readInt() read an int number of 785.477.224 which triggers the broker to allocate blindly this amount of mem.

We do not know yet what triggers the wrong byte sequence from the client, but on the brokers side, there should be a protection against this case.