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Date: Wed, 4 Dec 2013 21:16:35 +0000 (UTC)
From: "Oleg Kalnichevski (JIRA)" <jira@apache.org>
To: dev@hc.apache.org
Message-ID: <JIRA.12681290.1385484020643.73021.1386191795839@arcas>
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References: <JIRA.12681290.1385484020643@arcas>
Subject: [jira] [Resolved] (HTTPCORE-366) Infinite loop when using HTTPS
 server + NIO
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     [ https://issues.apache.org/jira/browse/HTTPCORE-366?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Oleg Kalnichevski resolved HTTPCORE-366.
----------------------------------------

    Resolution: Fixed

> Usually the reason of the timeout should be a dead connection, in which case there's no point in closing the SSL session.

Not quite. It perfectly normal for persistent connections to time out due to inactivity. Such connections should be closed gracefully. We ought not get too liberal with protocol compliance without a convincing reason. 

Here's the patch I ended up committing. Please review.

http://svn.apache.org/r1547915

Oleg

> Infinite loop when using HTTPS server + NIO
> -------------------------------------------
>
>                 Key: HTTPCORE-366
>                 URL: https://issues.apache.org/jira/browse/HTTPCORE-366
>             Project: HttpComponents HttpCore
>          Issue Type: Bug
>          Components: HttpCore NIO
>    Affects Versions: 4.2.5
>            Reporter: Isaac Cruz Ballesteros
>             Fix For: 4.3.1
>
>         Attachments: HTTPCORE-366.2.patch, HTTPCORE-366.patch
>
>
> This affects 4.2.5 but probably the newer versions as well.
> So I'm setting a HTTPS server using NIO to receive uploads from clients. Clients are using libcurl to upload.
> I've detected that sometimes (one every 2-4 days) the java process takes 100% cpu, and it's the "I/O dispatcher" thread which is in a infinite loop, with stack traces such as:
> "I/O dispatcher 1" prio=10 tid=0x00007f3e2400b000 nid=0x11c9 runnable [0x00007f3e3995e000]
>    java.lang.Thread.State: RUNNABLE
>         at org.apache.http.impl.nio.reactor.IOSessionImpl.getEventMask(IOSessionImpl.java:139)
>         - locked <0x00000000e09f5a70> (a org.apache.http.impl.nio.reactor.IOSessionImpl)
>         at org.apache.http.nio.reactor.ssl.SSLIOSession.updateEventMask(SSLIOSession.java:306)
>         at org.apache.http.nio.reactor.ssl.SSLIOSession.inboundTransport(SSLIOSession.java:411)
>         - locked <0x00000000e09f6938> (a org.apache.http.nio.reactor.ssl.SSLIOSession)
>         at org.apache.http.impl.nio.reactor.AbstractIODispatch.inputReady(AbstractIODispatch.java:121)
>         at org.apache.http.impl.nio.reactor.BaseIOReactor.validate(BaseIOReactor.java:220)
>         at org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:284)
>         at org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:106)
>         at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:613)
>         at java.lang.Thread.run(Thread.java:662)
> "I/O dispatcher 1" prio=10 tid=0x00007f01a000b000 nid=0x1f78 runnable [0x00007f01d1cf6000]
>    java.lang.Thread.State: RUNNABLE
>         at org.apache.http.nio.reactor.ssl.SSLIOSession.doHandshake(SSLIOSession.java:276)
>         at org.apache.http.nio.reactor.ssl.SSLIOSession.isAppInputReady(SSLIOSession.java:381)
>         - locked <0x00000000e08b5178> (a org.apache.http.nio.reactor.ssl.SSLIOSession)
>         at org.apache.http.impl.nio.reactor.AbstractIODispatch.inputReady(AbstractIODispatch.java:118)
>         at org.apache.http.impl.nio.reactor.BaseIOReactor.readable(BaseIOReactor.java:160)
>         at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvent(AbstractIOReactor.java:342)
>         at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvents(AbstractIOReactor.java:320)
>         at org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:280)
>         at org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:106)
>         at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:613)
>         at java.lang.Thread.run(Thread.java:662)
> The socket in the server side is in CLOSE_WAIT state, so the client closed the connection but not the server.
> I added some logs to the httpcore-nio library to try to know some details of when this issue happens, specifically in AbstractIODispatch.inputReady() and in several places in SSLIOSession, to print the SSLEngineResult after doWrap and doUnwrap in doHandshake() and decryptData() method, and also in isAppInputReady() to print bytesRead, inEncrypted buffer state, and HandshakeStatus.
> I'm going to explain what I found, if you want I can attach the complete generated logs.
> So after handshake and some data exchange, we start receiving data from client, and we keep getting a BUFFER_UNDERFLOW until the inEncrypted buffer is complete:
> 2013-11-26 02:59:37,914 [I/O dispatcher 1] ssl.SSLIOSession: bytesRead from socket: 1346, inEncrypted: java.nio.HeapByteBuffer[pos=16665 lim=16665 cap=16665]
> 2013-11-26 02:59:37,915 [I/O dispatcher 1] ssl.SSLIOSession: result from unwrap: Status = OK HandshakeStatus = NOT_HANDSHAKING
> bytesConsumed = 16421 bytesProduced = 16384
> We produce 16384 bytes of user data, and from here we start receiving more data:
> 2013-11-26 02:59:37,915 [I/O dispatcher 1] ssl.SSLIOSession: bytesRead from socket: 34, inEncrypted: java.nio.HeapByteBuffer[pos=278 lim=16665 cap=16665]
> 2013-11-26 02:59:37,948 [I/O dispatcher 1] ssl.SSLIOSession: bytesRead from socket: 1380, inEncrypted: java.nio.HeapByteBuffer[pos=1658 lim=16665 cap=16665]
> 2013-11-26 02:59:37,982 [I/O dispatcher 1] ssl.SSLIOSession: bytesRead from socket: 1380, inEncrypted: java.nio.HeapByteBuffer[pos=3038 lim=16665 cap=16665]
> 2013-11-26 02:59:38,017 [I/O dispatcher 1] ssl.SSLIOSession: bytesRead from socket: 1380, inEncrypted: java.nio.HeapByteBuffer[pos=4418 lim=16665 cap=16665]
> 2013-11-26 02:59:38,051 [I/O dispatcher 1] ssl.SSLIOSession: bytesRead from socket: 1380, inEncrypted: java.nio.HeapByteBuffer[pos=5798 lim=16665 cap=16665]
> 2013-11-26 02:59:38,391 [I/O dispatcher 1] ssl.SSLIOSession: bytesRead from socket: 4140, inEncrypted: java.nio.HeapByteBuffer[pos=9938 lim=16665 cap=16665]
> 2013-11-26 02:59:38,440 [I/O dispatcher 1] ssl.SSLIOSession: bytesRead from socket: 5520, inEncrypted: java.nio.HeapByteBuffer[pos=15458 lim=16665 cap=16665]
> Between all these recvs we always get a BUFFER_UNDERFLOW from unwrap()
> From that time (note that the inEncrypted buffer is still not full) we stop receiving any data. For some reason there's a call to isAppInputReady() every second, which always do the same: bytesRead = 0, buffer_underflow. I don't know why this is called even though this channel hasn't been "selected" by select(), I think it comes from the validate() call in AbstractIOReactor line 284:
>                 // Validate active channels
>                 validate(this.selector.keys());
> But anyway, this isn't very important.
> The point is after 30 seconds from last packet sent, the client closes connection. This is probably a timeout, not sure, and I also don't understand why the server thinks it needs more data to decrypt, and why the client does not send more data if that's true.... In any case, after 30 seconds this is what happens:
> 2013-11-26 03:00:07,481 [I/O dispatcher 1] nio.DefaultHttpServerIODispatch: inputReady on 192.168.100.40:9443<->75.37.10.219:40186[ACTIVE][r:r]
> 2013-11-26 03:00:07,481 [I/O dispatcher 1] ssl.SSLIOSession: bytesRead from socket: 0, inEncrypted: java.nio.HeapByteBuffer[pos=15458 lim=16665 cap=16665]
> 2013-11-26 03:00:07,481 [I/O dispatcher 1] ssl.SSLIOSession: handshake status: NOT_HANDSHAKING
> 2013-11-26 03:00:07,481 [I/O dispatcher 1] ssl.SSLIOSession: result from unwrap: Status = BUFFER_UNDERFLOW HandshakeStatus = NOT_HANDSHAKING
> 2013-11-26 03:00:08,483 [I/O dispatcher 1] nio.DefaultHttpServerIODispatch: inputReady on 192.168.100.40:9443<->75.37.10.219:40186[ACTIVE][rw:r]
> 2013-11-26 03:00:08,483 [I/O dispatcher 1] ssl.SSLIOSession: bytesRead from socket: 0, inEncrypted: java.nio.HeapByteBuffer[pos=15458 lim=16665 cap=16665]
> 2013-11-26 03:00:08,483 [I/O dispatcher 1] ssl.SSLIOSession: result from wrap: Status = CLOSED HandshakeStatus = NEED_UNWRAP
> bytesConsumed = 0 bytesProduced = 37
> 2013-11-26 03:00:08,483 [I/O dispatcher 1] ssl.SSLIOSession: handshake status: NEED_UNWRAP
> From here it starts an infinite loop: it's calling continuously the inputReady() method, but it never closes the socket, it keeps getting status = BUFFER_UNDERFLOW when calling unwrap() and handshake status = NEED_UNWRAP (as the client has closed SSL session)


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