[jira] [Created] (SSHD-921) OutOfMemory Error in extreme situations

["Zhenliang Su (JIRA)" <ji...@apache.org>]

Zhenliang Su created SSHD-921:
---------------------------------

             Summary: OutOfMemory Error in extreme situations
                 Key: SSHD-921
                 URL: https://issues.apache.org/jira/browse/SSHD-921
             Project: MINA SSHD
          Issue Type: Bug
    Affects Versions: 1.7.0, 2.3.0
            Reporter: Zhenliang Su
         Attachments: Main.java, jstack.txt

The demo code run in my local machine.
 When I 'ssh root@127.0.0.1 -p 2233', my demo will use the agent forwarding feature to login 10.10.16.201.
 In most cases, it's ok. But in few cases, for example, client disconnect suddenly, it will lead to OutOfMemory Error.
 To simulate this scenario of OutOfMemory Error, I did some trick to the sshd code:
 1. In org.apache.sshd.common.future.DefaultSshFuture#setValue:
{code:java}
public void setValue(Object newValue) {
    	// to simulate race condition
    	try {
    		Thread.sleep(10);
    	} catch (Exception e) {
    		// ignore
    	}
        synchronized (lock) {
            // Allow only once.
            if (result != null) {
                return;
            }

            result = (newValue != null) ? newValue : GenericUtils.NULL;
            lock.notifyAll();
        }

        notifyListeners();
    }
{code}
2. In org.apache.sshd.agent.local.AgentForwardedChannel#doWriteData:
{code:java}
 protected void doWriteData(byte[] data, int off, long len) throws IOException {
        ValidateUtils.checkTrue(len <= Integer.MAX_VALUE, "Data length exceeds int boundaries: %d", len);

        Buffer message = null;
        synchronized (receiveBuffer) {
            receiveBuffer.putBuffer(new ByteArrayBuffer(data, off, (int) len));
            // to simulate client disconnect suddenly
            if (false && receiveBuffer.available() >= 4) {
                off = receiveBuffer.rpos();
                len = receiveBuffer.getInt();
                receiveBuffer.rpos(off);
                if (receiveBuffer.available() >= (4 + len)) {
                    message = new ByteArrayBuffer(receiveBuffer.getBytes());
                    receiveBuffer.compact();
                }
            }
        }
        if (message != null) {
            synchronized (messages) {
                messages.offer(message);
                messages.notifyAll();
            }
        }
    }
{code}
After two munites, my console displayed '[sshd-SshClient[720b3c53]-timer-thread-1] INFO org.apache.sshd.client.session.ClientSessionImpl - Disconnecting(ClientSessionImpl[root@/10.10.16.201:8022]): SSH2_DISCONNECT_PROTOCOL_ERROR - Session has timed out waiting for authentication after 120000 ms.' every second, and finally lead to OutOfMemory Error.



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