Apache MINA sshd client: proxy support

This is not about the ssh config ProxyCommand but about programmatic
support for HTTP and SOCKS5 proxies. Eclipse allows the user to
specify such proxies, and JSch at least contains code to connect
through proxies. So our Apache MINA sshd client also should be able
to do this.

Add interfaces and provide two implementations for HTTP and SOCKS5
proxies. Adapt the core code to be able to deal with proxy connections
at all. The built-in client-side support for this in sshd 2.0.0 is
woefully inadequate.

Tested manually by running proxies and then fetching various real-
world repositories via these proxies from different servers. Proxies
tested: ssh -D (SOCKS, anonymous), tinyproxy (HTTP, anonymous), and
3proxy (SOCKS & HTTP, username-password authentication). The GSS-API
authentication is untested since I have no Kerberos setup.

Bug: 520927
Change-Id: I1a5c34687d439b3ef8373c5d58e24004f93e63ae
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

2 files changed, 148 insertions, 1 deletions

diff --git a/org.eclipse.jgit.ssh.apache.test/tst/org/eclipse/jgit/internal/transport/sshd/proxy/HttpParserTest.java b/org.eclipse.jgit.ssh.apache.test/tst/org/eclipse/jgit/internal/transport/sshd/proxy/HttpParserTest.java
new file mode 100644
index 0000000000..b8e85493aa
--- /dev/null
+++ b/org.eclipse.jgit.ssh.apache.test/tst/org/eclipse/jgit/internal/transport/sshd/proxy/HttpParserTest.java
@@ -0,0 +1,146 @@
+/*
+ * Copyright (C) 2018, Thomas Wolf <thomas.wolf@paranor.ch>
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package org.eclipse.jgit.internal.transport.sshd.proxy;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.junit.Test;
+
+public class HttpParserTest {
+
+	private static final String STATUS_LINE = "HTTP/1.1. 407 Authentication required";
+
+	@Test
+	public void testEmpty() throws Exception {
+		String[] lines = { STATUS_LINE };
+		List<AuthenticationChallenge> challenges = HttpParser
+				.getAuthenticationHeaders(Arrays.asList(lines),
+						"WWW-Authenticate:");
+		assertTrue("No challenges expected", challenges.isEmpty());
+	}
+
+	@Test
+	public void testRFC7235Example() throws Exception {
+		// The example from RFC 7235, sec. 4.1, slightly modified ("kind"
+		// argument with whitespace around '=')
+		String[] lines = { STATUS_LINE,
+				"WWW-Authenticate: Newauth realm=\"apps\", type=1  , kind = \t2 ",
+				"   \t  title=\"Login to \\\"apps\\\"\", Basic realm=\"simple\"" };
+		List<AuthenticationChallenge> challenges = HttpParser
+				.getAuthenticationHeaders(Arrays.asList(lines),
+						"WWW-Authenticate:");
+		assertEquals("Unexpected number of challenges", 2, challenges.size());
+		assertNull("No token expected", challenges.get(0).getToken());
+		assertNull("No token expected", challenges.get(1).getToken());
+		assertEquals("Unexpected mechanism", "Newauth",
+				challenges.get(0).getMechanism());
+		assertEquals("Unexpected mechanism", "Basic",
+				challenges.get(1).getMechanism());
+		Map<String, String> expectedArguments = new LinkedHashMap<>();
+		expectedArguments.put("realm", "apps");
+		expectedArguments.put("type", "1");
+		expectedArguments.put("kind", "2");
+		expectedArguments.put("title", "Login to \"apps\"");
+		assertEquals("Unexpected arguments", expectedArguments,
+				challenges.get(0).getArguments());
+		expectedArguments.clear();
+		expectedArguments.put("realm", "simple");
+		assertEquals("Unexpected arguments", expectedArguments,
+				challenges.get(1).getArguments());
+	}
+
+	@Test
+	public void testMultipleHeaders() {
+		String[] lines = { STATUS_LINE,
+				"Server: Apache",
+				"WWW-Authenticate: Newauth realm=\"apps\", type=1  , kind = \t2 ",
+				"   \t  title=\"Login to \\\"apps\\\"\", Basic realm=\"simple\"",
+				"Content-Type: text/plain",
+				"WWW-Authenticate: Other 0123456789===  , YetAnother, ",
+				"WWW-Authenticate: Negotiate   ",
+				"WWW-Authenticate: Negotiate a87421000492aa874209af8bc028" };
+		List<AuthenticationChallenge> challenges = HttpParser
+				.getAuthenticationHeaders(Arrays.asList(lines),
+						"WWW-Authenticate:");
+		assertEquals("Unexpected number of challenges", 6, challenges.size());
+		assertEquals("Mismatched challenge", "Other",
+				challenges.get(2).getMechanism());
+		assertEquals("Token expected", "0123456789===",
+				challenges.get(2).getToken());
+		assertEquals("Mismatched challenge", "YetAnother",
+				challenges.get(3).getMechanism());
+		assertNull("No token expected", challenges.get(3).getToken());
+		assertTrue("No arguments expected",
+				challenges.get(3).getArguments().isEmpty());
+		assertEquals("Mismatched challenge", "Negotiate",
+				challenges.get(4).getMechanism());
+		assertNull("No token expected", challenges.get(4).getToken());
+		assertEquals("Mismatched challenge", "Negotiate",
+				challenges.get(5).getMechanism());
+		assertEquals("Token expected", "a87421000492aa874209af8bc028",
+				challenges.get(5).getToken());
+	}
+
+	@Test
+	public void testStopOnEmptyLine() {
+		String[] lines = { STATUS_LINE, "Server: Apache",
+				"WWW-Authenticate: Newauth realm=\"apps\", type=1  , kind = \t2 ",
+				"   \t  title=\"Login to \\\"apps\\\"\", Basic realm=\"simple\"",
+				"Content-Type: text/plain",
+				"WWW-Authenticate: Other 0123456789===", "",
+				// Not headers anymore; this would be the body
+				"WWW-Authenticate: Negotiate   ",
+				"WWW-Authenticate: Negotiate a87421000492aa874209af8bc028" };
+		List<AuthenticationChallenge> challenges = HttpParser
+				.getAuthenticationHeaders(Arrays.asList(lines),
+						"WWW-Authenticate:");
+		assertEquals("Unexpected number of challenges", 3, challenges.size());
+	}
+}
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 cbbc6386f0..69a9165aa7 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
@@ -61,7 +61,8 @@ public class ApacheSshTest extends SshTestBase {
 
 	@Override
 	protected SshSessionFactory createSessionFactory() {
-		SshdSessionFactory result = new SshdSessionFactory(new JGitKeyCache());
+		SshdSessionFactory result = new SshdSessionFactory(new JGitKeyCache(),
+				null);
 		// The home directory is mocked at this point!
 		result.setHomeDirectory(FS.DETECTED.userHome());
 		result.setSshDirectory(sshDir);