sshd: work around a race condition in Apache MINA sshd 2.4.0/2.5.x

When exceptions occur very early in the SSH connection setup, it's
possible that an exception gets lost. A subsequent authentication
attempt may then never be notified of the failure, and then wait
indefinitely or until its timeout expires.

This is caused by race conditions in sshd. The issue has been reported
upstream as SSHD-1050,[1] but will be fixed at the earliest in sshd
2.6.0.

[1] https://issues.apache.org/jira/projects/SSHD/issues/SSHD-1050

Bug: 565394
Change-Id: If9b62839db38f9e59a5e1137c2257039ba82de98
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

1 files changed, 12 insertions, 6 deletions

diff --git a/org.eclipse.jgit.ssh.apache.test/tst/org/eclipse/jgit/transport/sshd/ApacheSshTest.java b/org.eclipse.jgit.ssh.apache.test/tst/org/eclipse/jgit/transport/sshd/ApacheSshTest.java
index f27af6e196..651ae7dec1 100644
--- a/org.eclipse.jgit.ssh.apache.test/tst/org/eclipse/jgit/transport/sshd/ApacheSshTest.java
+++ b/org.eclipse.jgit.ssh.apache.test/tst/org/eclipse/jgit/transport/sshd/ApacheSshTest.java
@@ -11,6 +11,7 @@ package org.eclipse.jgit.transport.sshd;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 
 import java.io.File;
@@ -159,7 +160,7 @@ public class ApacheSshTest extends SshTestBase {
 				"IdentityFile " + privateKey1.getAbsolutePath());
 	}
 
-	@Test (expected = TransportException.class)
+	@Test
 	public void testHugePreamble() throws Exception {
 		// Test that the connection fails when the preamble is longer than 64k.
 		StringBuilder b = new StringBuilder();
@@ -172,11 +173,16 @@ public class ApacheSshTest extends SshTestBase {
 			lines[i] = line;
 		}
 		server.setPreamble(lines);
-		cloneWith(
-				"ssh://" + TEST_USER + "@localhost:" + testPort
-						+ "/doesntmatter",
-				defaultCloneDir, null,
-				"IdentityFile " + privateKey1.getAbsolutePath());
+		TransportException e = assertThrows(TransportException.class,
+				() -> cloneWith(
+						"ssh://" + TEST_USER + "@localhost:" + testPort
+								+ "/doesntmatter",
+						defaultCloneDir, null,
+						"IdentityFile " + privateKey1.getAbsolutePath()));
+		// The assertions test that we don't run into bug 565394 / SSHD-1050
+		assertFalse(e.getMessage().contains("timeout"));
+		assertTrue(e.getMessage().contains("65536")
+				|| e.getMessage().contains("closed"));
 	}
 
 	/**