Thomas Wolf created SSHD-1295:
---------------------------------
Summary: Connection attempt not canceled when a connection timeout
occurs
Key: SSHD-1295
URL: https://issues.apache.org/jira/browse/SSHD-1295
Project: MINA SSHD
Issue Type: Bug
Affects Versions: 2.9.2
Reporter: Thomas Wolf
This is not a new bug; it's also present in earlier versions.
When {{client.connect().verify(timeout)}} times out, the underlying
asynchronous connection attempt still continues _and may still succeed_. If
that happens, there is a connection and session that the user cannot use or
close. (Short of calling verify().getSession() again, but that is a pattern I
have never seen, and it also makes using a timeout rather useless.)
This means that timeouts are inherently unreliable.
Here's a simple test case illustrating this problem (for
{{org.apache.sshd.client.ClientTest}}):
{code:java}
@Test
public void testConnectTimeout() throws Exception {
client.start();
try {
ConnectFuture future = client.connect(getCurrentTestName(),
TEST_LOCALHOST, port);
try {
future.verify(1);
fail("Timeout expected");
} catch (InterruptedIOException | SshException e) {
ClientSession session = null;
try {
session = future.verify(CONNECT_TIMEOUT).getSession();
} catch (SshException e2) {
assertTrue("Expected a timeout, got " + e2,
e2.getMessage().contains("timeout"));
}
if (session != null) {
assertTrue("Session should be closed", session.isClosed() ||
session.isClosing());
}
}
} finally {
client.stop();
}
}
{code}
This test fails.
When the {{ConnectFuture}} times out (or is canceled, or waiting is
interrupted), the underlying {{IoConnectFuture}} must be canceled. If we do get
an {{IoSession}} all the same, but the {{ConnectFuture}} is already canceled or
timed out, the {{IoSession}} must be closed immediately. Preferrably before a
{{Session}} is created at all; otherwise, that SSH session must be closed, too.
Creating a {{ClientSession}} already starts the application-level protocol
(sending the SSH ident, or if a proxy is used, the proxy connect request).
The test also highlights another problem: there is no clear indication that the
failure of {{verify()}} indicates a timeout. Probably there should be a
dedicated exception for this, or at least the {{SshException}} should have a
{{TimeoutException}} as cause.
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