Yumin Sang created SSHD-902:
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Summary: Local port forwarding: EOF is not handled properly
Key: SSHD-902
URL: https://issues.apache.org/jira/browse/SSHD-902
Project: MINA SSHD
Issue Type: Bug
Affects Versions: 2.1.0
Environment: OS: both Windows 10 and Red Hat Enterprise Linux Server
release 7.4 (Maipo) Linux 4.1.12-124.19.2.el7uek.x86_64 x86_64
JDK: 1.8.0_201
SSHD: 2.1.0
Reporter: Yumin Sang
Attachments: AbstractServerCloseTestSupport.java,
ApacheServerApacheClientTest.java, packets.PNG
Set remote port to a real listening port but is not for DB connection. Start a
local port forwarding. Try getting a connection through the established SSH
tunnel. This operation is expected to be finished with some error, but it hangs.
Reproduce steps:
# prepare a Linux server and find a listening port, such as 2049, which is not
of DB listener.
# get attached demo code: ApacheServerApacheClientTest.java and
AbstractServerCloseTestSupport.java. They are modified from the ones in
mina-sshd-2.1.0\sshd-core\src\test\java\org\apache\sshd\common\forward. Please
replace the corresponding ones.
# download ojdbc8.jar from
[https://www.oracle.com/technetwork/database/features/jdbc/jdbc-ucp-122-3110062.html?|https://www.oracle.com/technetwork/database/features/jdbc/jdbc-ucp-122-3110062.html]
and add it to classpath.
# set up a local port forwarding tunnel by Putty or other tools. Set the
forwarded local port to 37777, remote server/port to the server/port in step 1.
# run ApacheServerApacheClientTest.java. It finishes with error like
java.io.IOException: Got minus one from a read call. This is expected behavior.
# change
org.apache.sshd.common.forward.AbstractServerCloseTestSupport#testLocalPortForwardOneBuffer:
uncomment line "int serverPort = startLocalPF();" and comment line "int
serverPort = 37777;"
# run ApacheServerApacheClientTest.java again and it hangs.
By capturing loopback packets, it can be found the interactions are same, but
SSHD make different process from what Putty does. In attached snapshot, the
"nfs" is of port 2049.
Did a bit digging up, and it seems that EOF is not handled properly. Here is a
call stack:
handleEof:873, AbstractChannel (org.apache.sshd.common.channel)
channelEof:498, AbstractConnectionService
(org.apache.sshd.common.session.helpers)
process:357, AbstractConnectionService (org.apache.sshd.common.session.helpers)
doHandleMessage:626, AbstractSession (org.apache.sshd.common.session.helpers)
handleMessage:559, AbstractSession (org.apache.sshd.common.session.helpers)
decode:1542, AbstractSession (org.apache.sshd.common.session.helpers)
messageReceived:520, AbstractSession (org.apache.sshd.common.session.helpers)
messageReceived:63, AbstractSessionIoHandler
(org.apache.sshd.common.session.helpers)
handleReadCycleCompletion:339, Nio2Session (org.apache.sshd.common.io.nio2)
onCompleted:318, Nio2Session$1 (org.apache.sshd.common.io.nio2)
onCompleted:315, Nio2Session$1 (org.apache.sshd.common.io.nio2)
lambda$completed$0:38, Nio2CompletionHandler (org.apache.sshd.common.io.nio2)
run:-1, 391147216
(org.apache.sshd.common.io.nio2.Nio2CompletionHandler$$Lambda$73)
doPrivileged:-1, AccessController (java.security)
completed:37, Nio2CompletionHandler (org.apache.sshd.common.io.nio2)
invokeUnchecked:126, Invoker (sun.nio.ch)
run:218, Invoker$2 (sun.nio.ch)
run:112, AsynchronousChannelGroupImpl$1 (sun.nio.ch)
runWorker:1149, ThreadPoolExecutor (java.util.concurrent)
run:624, ThreadPoolExecutor$Worker (java.util.concurrent)
run:748, Thread (java.lang)
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