undefect. CWE-407 — 63 sites patched across 27 ecosystems

Authors: russell@unturf.com · brackishbert@gmail.com · foxhop.net · TimeHexOn.com

Patches, unit tests, benchmarks, whitepaper, and outreach briefs.
Public domain — no copyright claimed. Use freely.

test/jdk/java/net/SocketImpl/SocketImplCombinations.java

@@ -0,0 +1,864 @@
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8220493
+ * @modules java.base/java.net:+open java.base/sun.nio.ch:+open
+ * @run testng/othervm SocketImplCombinations
+ * @summary Test Socket and ServerSocket with combinations of SocketImpls
+ */
+
+import java.io.FileDescriptor;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.lang.reflect.Field;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.Proxy;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.net.SocketAddress;
+import java.net.SocketImpl;
+import java.net.SocketImplFactory;
+import java.nio.channels.ServerSocketChannel;
+import java.nio.channels.SocketChannel;
+import java.util.function.BiConsumer;
+
+import org.testng.annotations.Test;
+import static org.testng.Assert.*;
+
+@Test
+public class SocketImplCombinations {
+
+    /**
+     * Test creating an unconnected Socket, it should be created with a platform SocketImpl.
+     */
+    public void testNewSocket1() throws IOException {
+        try (Socket s = new Socket()) {
+            SocketImpl si = getSocketImpl(s);
+            assertTrue(isSocksSocketImpl(si));
+            SocketImpl delegate = getDelegate(si);
+            assertTrue(isPlatformSocketImpl(delegate));
+        }
+    }
+
+    /**
+     * Test creating a connected Socket, it should be created with a platform SocketImpl.
+     */
+    public void testNewSocket2() throws IOException {
+        try (ServerSocket ss = boundServerSocket()) {
+            try (Socket s = new Socket(ss.getInetAddress(), ss.getLocalPort())) {
+                SocketImpl si = getSocketImpl(s);
+                assertTrue(isSocksSocketImpl(si));
+                SocketImpl delegate = getDelegate(si);
+                assertTrue(isPlatformSocketImpl(delegate));
+            }
+        }
+    }
+
+    /**
+     * Test creating a Socket for a DIRECT connection, it should be created with a
+     * platform SocketImpl.
+     */
+    public void testNewSocket3() throws IOException {
+        try (Socket s = new Socket(Proxy.NO_PROXY)) {
+            SocketImpl si = getSocketImpl(s);
+            assertTrue(isPlatformSocketImpl(si));
+        }
+    }
+
+    /**
+     * Test creating a Socket for a SOCKS connection, it should be created with a
+     * SOCKS SocketImpl.
+     */
+    public void testNewSocket4() throws IOException {
+        var address = new InetSocketAddress("127.0.0.1", 1080);
+        var socksProxy = new Proxy(Proxy.Type.SOCKS, address);
+        try (Socket s = new Socket(socksProxy)) {
+            SocketImpl si = getSocketImpl(s);
+            assertTrue(isSocksSocketImpl(si));
+            SocketImpl delegate = getDelegate(si);
+            assertTrue(isPlatformSocketImpl(delegate));
+        }
+    }
+
+    /**
+     * Test creating a Socket for a HTTP proxy connection, it should be created with
+     * a HTTP proxy SocketImpl.
+     */
+    public void testNewSocket5() throws IOException {
+        var address = new InetSocketAddress("127.0.0.1", 8080);
+        var httpProxy = new Proxy(Proxy.Type.HTTP, address);
+        try (Socket s = new Socket(httpProxy)) {
+            SocketImpl si = getSocketImpl(s);
+            assertTrue(isHttpConnectSocketImpl(si));
+            SocketImpl delegate = getDelegate(si);
+            assertTrue(isPlatformSocketImpl(delegate));
+        }
+    }
+
+    /**
+     * Test creating a Socket no SocketImpl. A platform SocketImpl should be
+     * created lazily.
+     */
+    public void testNewSocket6() throws IOException {
+        Socket s = new Socket((SocketImpl) null) { };
+        try (s) {
+            assertTrue(getSocketImpl(s) == null);
+            s.bind(loopbackSocketAddress());   // force SocketImpl to be created
+            SocketImpl si = getSocketImpl(s);
+            assertTrue(isSocksSocketImpl(si));
+            SocketImpl delegate = getDelegate(si);
+            assertTrue(isPlatformSocketImpl(delegate));
+        }
+    }
+
+    /**
+     * Test creating a Socket with a custom SocketImpl.
+     */
+    public void testNewSocket7() throws IOException {
+        Socket s = new Socket(new CustomSocketImpl(false)) { };
+        try (s) {
+            SocketImpl si = getSocketImpl(s);
+            assertTrue(si instanceof CustomSocketImpl);
+        }
+    }
+
+    /**
+     * Test creating a Socket when there is a SocketImplFactory set.
+     */
+    public void testNewSocket8() throws IOException {
+        setSocketSocketImplFactory(() -> new CustomSocketImpl(false));
+        try (Socket s = new Socket()) {
+            SocketImpl si = getSocketImpl(s);
+            assertTrue(si instanceof CustomSocketImpl);
+        } finally {
+            setSocketSocketImplFactory(null);
+        }
+    }
+
+    /**
+     * Test creating a Socket for a DIRECT connection when there is a
+     * SocketImplFactory set.
+     */
+    public void testNewSocket9() throws IOException {
+        setSocketSocketImplFactory(() -> new CustomSocketImpl(false));
+        try (Socket s = new Socket(Proxy.NO_PROXY)) {
+            SocketImpl si = getSocketImpl(s);
+            assertTrue(si instanceof CustomSocketImpl);
+        } finally {
+            setSocketSocketImplFactory(null);
+        }
+    }
+
+    /**
+     * Test creating a Socket for a SOCKS connection when there is a
+     * SocketImplFactory set.
+     */
+    public void testNewSocket10() throws IOException {
+        var address = new InetSocketAddress("127.0.0.1", 1080);
+        var socksProxy = new Proxy(Proxy.Type.SOCKS, address);
+        setSocketSocketImplFactory(() -> new CustomSocketImpl(false));
+        try (Socket s = new Socket(socksProxy)) {
+            SocketImpl si = getSocketImpl(s);
+            assertTrue(isSocksSocketImpl(si));
+            SocketImpl delegate = getDelegate(si);
+            assertTrue(isPlatformSocketImpl(delegate));
+        } finally {
+            setSocketSocketImplFactory(null);
+        }
+    }
+
+    /**
+     * Test creating a Socket for a HTTP proxy connection when there is a
+     * SocketImplFactory set.
+     */
+    public void testNewSocket11() throws IOException {
+        var address = new InetSocketAddress("127.0.0.1", 8080);
+        var httpProxy = new Proxy(Proxy.Type.HTTP, address);
+        setSocketSocketImplFactory(() -> new CustomSocketImpl(false));
+        try (Socket s = new Socket(httpProxy)) {
+            SocketImpl si = getSocketImpl(s);
+            assertTrue(isHttpConnectSocketImpl(si));
+            SocketImpl delegate = getDelegate(si);
+            assertTrue(isPlatformSocketImpl(delegate));
+        } finally {
+            setSocketSocketImplFactory(null);
+        }
+    }
+
+    /**
+     * Test creating a Socket no SocketImpl when there is a SocketImplFactory set.
+     */
+    public void testNewSocket12() throws IOException {
+        setSocketSocketImplFactory(() -> new CustomSocketImpl(false));
+        try {
+            Socket s = new Socket((SocketImpl) null) { };
+            try (s) {
+                assertTrue(getSocketImpl(s) == null);
+                s.bind(loopbackSocketAddress());   // force SocketImpl to be created
+                assertTrue(getSocketImpl(s) instanceof CustomSocketImpl);
+            }
+        } finally {
+            setSocketSocketImplFactory(null);
+        }
+    }
+
+    /**
+     * Test creating an unbound ServerSocket, it should be created with a platform
+     * SocketImpl.
+     */
+    public void testNewServerSocket1() throws IOException {
+        try (ServerSocket ss = new ServerSocket()) {
+            SocketImpl si = getSocketImpl(ss);
+            assertTrue(isPlatformSocketImpl(si));
+        }
+    }
+
+    /**
+     * Test creating a bound ServerSocket, it should be created with a platform
+     * SocketImpl.
+     */
+    public void testNewServerSocket2() throws IOException {
+        try (ServerSocket ss = new ServerSocket(0)) {
+            SocketImpl si = getSocketImpl(ss);
+            assertTrue(isPlatformSocketImpl(si));
+        }
+    }
+
+    /**
+     * Test creating a ServerSocket with a custom SocketImpl.
+     */
+    public void testNewServerSocket3() throws IOException {
+        ServerSocket ss = new ServerSocket(new CustomSocketImpl(true)) { };
+        try (ss) {
+            SocketImpl si = getSocketImpl(ss);
+            assertTrue(si instanceof CustomSocketImpl);
+        }
+    }
+
+    /**
+     * Test creating an unbound ServerSocket when there is a SocketImplFactory set.
+     */
+    public void testNewServerSocket4() throws IOException {
+        setServerSocketImplFactory(() -> new CustomSocketImpl(true));
+        try (ServerSocket ss = new ServerSocket()) {
+            SocketImpl si = getSocketImpl(ss);
+            assertTrue(si instanceof CustomSocketImpl);
+        } finally {
+            setServerSocketImplFactory(null);
+        }
+    }
+
+    /**
+     * Test creating a bound ServerSocket when there is a SocketImplFactory set.
+     */
+    public void testNewServerSocket5() throws IOException {
+        setServerSocketImplFactory(() -> new CustomSocketImpl(true));
+        try (ServerSocket ss = new ServerSocket(0)) {
+            SocketImpl si = getSocketImpl(ss);
+            assertTrue(si instanceof CustomSocketImpl);
+        } finally {
+            setServerSocketImplFactory(null);
+        }
+    }
+
+    /**
+     * Test ServerSocket.accept. The ServerSocket uses a platform SocketImpl,
+     * the Socket to accept is created with no SocketImpl.
+     */
+    public void testServerSocketAccept1() throws IOException {
+        var socket = new Socket((SocketImpl) null) { };
+        assertTrue(getSocketImpl(socket) == null);
+
+        serverSocketAccept(socket, (ss, s) -> {
+            assertTrue(isPlatformSocketImpl(getSocketImpl(ss)));
+            assertTrue(s == socket);
+            SocketImpl si = getSocketImpl(s);
+            assertTrue(isPlatformSocketImpl(si));
+            checkFields(si);
+        });
+    }
+
+    /**
+     * Test ServerSocket.accept. The ServerSocket uses a platform SocketImpl,
+     * the Socket to accept is created with no SocketImpl, and there is a custom
+     * client SocketImplFactory set.
+     */
+    public void testServerSocketAccept2() throws IOException {
+        var socket = new Socket((SocketImpl) null) { };
+        assertTrue(getSocketImpl(socket) == null);
+
+        serverSocketAccept(socket, () -> new CustomSocketImpl(false), (ss, s) -> {
+            assertTrue(isPlatformSocketImpl(getSocketImpl(ss)));
+            assertTrue(s == socket);
+            SocketImpl si = getSocketImpl(s);
+            assertTrue(isPlatformSocketImpl(si));
+            checkFields(si);
+        });
+    }
+
+    /**
+     * Test ServerSocket.accept. The ServerSocket uses a platform SocketImpl,
+     * the Socket to accept is created with a SocketImpl that delegates to a
+     * platform SocketImpl.
+     */
+    public void testServerSocketAccept3() throws IOException {
+        var socket = new Socket();
+        SocketImpl si = getSocketImpl(socket);
+        assertTrue(isSocksSocketImpl(si));
+        SocketImpl delegate = getDelegate(si);
+        assertTrue(isPlatformSocketImpl(delegate));
+
+        serverSocketAccept(socket, (ss, s) -> {
+            assertTrue(isPlatformSocketImpl(getSocketImpl(ss)));
+            assertTrue(s == socket);
+            SocketImpl psi = getSocketImpl(socket);
+            assertTrue(isPlatformSocketImpl(psi));
+            checkFields(psi);
+        });
+    }
+
+    /**
+     * Test ServerSocket.accept. The ServerSocket uses a platform SocketImpl,
+     * the Socket to accept is created with a custom SocketImpl.
+     */
+    public void testServerSocketAccept4a() throws IOException {
+        SocketImpl clientImpl = new CustomSocketImpl(false);
+        Socket socket = new Socket(clientImpl) { };
+        assertTrue(getSocketImpl(socket) == clientImpl);
+
+        try (ServerSocket ss = serverSocketToAccept(socket)) {
+            expectThrows(IOException.class, ss::accept);
+        } finally {
+            socket.close();
+        }
+    }
+
+    public void testServerSocketAccept4b() throws IOException {
+        SocketImpl clientImpl = new CustomSocketImpl(false);
+        Socket socket = new Socket(clientImpl) { };
+        assertTrue(getSocketImpl(socket) == clientImpl);
+
+        setSocketSocketImplFactory(() -> new CustomSocketImpl(false));
+        try (ServerSocket ss = serverSocketToAccept(socket)) {
+            expectThrows(IOException.class, ss::accept);
+        } finally {
+            setSocketSocketImplFactory(null);
+            socket.close();
+        }
+    }
+
+    /**
+     * Test ServerSocket.accept. The ServerSocket uses a custom SocketImpl,
+     * the Socket to accept is created no SocketImpl.
+     */
+    public void testServerSocketAccept5a() throws IOException {
+        SocketImpl serverImpl = new CustomSocketImpl(true);
+        try (ServerSocket ss = new ServerSocket(serverImpl) { }) {
+            ss.bind(loopbackSocketAddress());
+            expectThrows(IOException.class, ss::accept);
+        }
+    }
+
+    public void testServerSocketAccept5b() throws IOException {
+        var socket = new Socket((SocketImpl) null) { };
+        assertTrue(getSocketImpl(socket) == null);
+
+        SocketImpl serverImpl = new CustomSocketImpl(true);
+        try (ServerSocket ss = serverSocketToAccept(serverImpl, socket)) {
+            expectThrows(IOException.class, ss::accept);
+        } finally {
+            socket.close();
+        }
+    }
+
+    public void testServerSocketAccept5c() throws IOException {
+        setServerSocketImplFactory(() -> new CustomSocketImpl(true));
+        try (ServerSocket ss = new ServerSocket(0)) {
+            expectThrows(IOException.class, ss::accept);
+        } finally {
+            setServerSocketImplFactory(null);
+        }
+    }
+
+    public void testServerSocketAccept5d() throws IOException {
+        var socket = new Socket((SocketImpl) null) { };
+        assertTrue(getSocketImpl(socket) == null);
+
+        setServerSocketImplFactory(() -> new CustomSocketImpl(true));
+        try (ServerSocket ss = serverSocketToAccept(socket)) {
+            expectThrows(IOException.class, ss::accept);
+        } finally {
+            setServerSocketImplFactory(null);
+            socket.close();
+        }
+    }
+
+    /**
+     * Test ServerSocket.accept. The ServerSocket uses a custom SocketImpl,
+     * the Socket to accept is created with no SocketImpl, and there is a custom
+     * client SocketImplFactory set.
+     */
+    public void testServerSocketAccept6() throws Exception {
+        var socket = new Socket((SocketImpl) null) { };
+        assertTrue(getSocketImpl(socket) == null);
+
+        SocketImpl serverImpl = new CustomSocketImpl(true);
+        SocketImplFactory clientFactory = () -> new CustomSocketImpl(false);
+        serverSocketAccept(serverImpl, socket, clientFactory, (ss, s) -> {
+            assertTrue(getSocketImpl(ss) == serverImpl);
+            SocketImpl si = getSocketImpl(s);
+            assertTrue(si instanceof CustomSocketImpl);
+            checkFields(si);
+        });
+    }
+
+    /**
+     * Test ServerSocket.accept. The ServerSocket uses a custom SocketImpl,
+     * the Socket to accept is created with a SocketImpl that delegates to a
+     * platform SocketImpl.
+     */
+    public void testServerSocketAccept7a() throws IOException {
+        var socket = new Socket();
+        SocketImpl si = getSocketImpl(socket);
+        assertTrue(isSocksSocketImpl(si));
+        SocketImpl delegate = getDelegate(si);
+        assertTrue(isPlatformSocketImpl(delegate));
+
+        SocketImpl serverImpl = new CustomSocketImpl(true);
+        try (ServerSocket ss = serverSocketToAccept(serverImpl, socket)) {
+            expectThrows(IOException.class, ss::accept);
+        } finally {
+            socket.close();
+        }
+    }
+
+    public void testServerSocketAccept7b() throws IOException {
+        var socket = new Socket();
+        SocketImpl si = getSocketImpl(socket);
+        assertTrue(isSocksSocketImpl(si));
+        SocketImpl delegate = getDelegate(si);
+        assertTrue(isPlatformSocketImpl(delegate));
+
+        setServerSocketImplFactory(() -> new CustomSocketImpl(true));
+        try (ServerSocket ss = serverSocketToAccept(socket)) {
+            expectThrows(IOException.class, ss::accept);
+        } finally {
+            setServerSocketImplFactory(null);
+            socket.close();
+        }
+    }
+
+    /**
+     * Test ServerSocket.accept. The ServerSocket uses a custom SocketImpl,
+     * the Socket to accept is created with a custom SocketImpl.
+     */
+    public void testServerSocketAccept8() throws Exception {
+        SocketImpl clientImpl = new CustomSocketImpl(false);
+        Socket socket = new Socket(clientImpl) { };
+        assertTrue(getSocketImpl(socket) == clientImpl);
+
+        SocketImpl serverImpl = new CustomSocketImpl(true);
+        SocketImplFactory clientFactory = () -> new CustomSocketImpl(false);
+        serverSocketAccept(serverImpl, socket, clientFactory, (ss, s) -> {
+            assertTrue(getSocketImpl(ss) == serverImpl);
+            assertTrue(getSocketImpl(s) == clientImpl);
+            checkFields(clientImpl);
+        });
+    }
+
+    /**
+     * Creates a ServerSocket that returns the given Socket from accept.
+     * The consumer is invoked with the server socket and the accepted socket.
+     */
+    static void serverSocketAccept(Socket socket,
+                                   BiConsumer<ServerSocket, Socket> consumer)
+        throws IOException
+    {
+        Socket s1 = null;
+        Socket s2 = null;
+        try (ServerSocket ss = serverSocketToAccept(socket)) {
+            s1 = new Socket(ss.getInetAddress(), ss.getLocalPort());
+            s2 = ss.accept();
+            consumer.accept(ss, s2);
+        } finally {
+            if (s1 != null) s1.close();
+            if (s2 != null) s2.close();
+        }
+    }
+
+    /**
+     * Creates a ServerSocket that returns the given Socket from accept. The
+     * given SocketImplFactory is set during the accept and the consumer is
+     * invoked when the server socket and the accepted socket.
+     */
+    static void serverSocketAccept(Socket socket,
+                                   SocketImplFactory factory,
+                                   BiConsumer<ServerSocket, Socket> consumer)
+        throws IOException
+    {
+        Socket s1 = null;
+        Socket s2 = null;
+        try (ServerSocket ss = serverSocketToAccept(socket)) {
+            s1 = new Socket(ss.getInetAddress(), ss.getLocalPort());
+            setSocketSocketImplFactory(factory);
+            try {
+                s2 = ss.accept();
+            } finally {
+                setSocketSocketImplFactory(null);
+            }
+            consumer.accept(ss, s2);
+        } finally {
+            if (s1 != null) s1.close();
+            if (s2 != null) s2.close();
+        }
+    }
+
+    /**
+     * Creates a ServerSocket with a SocketImpl returns the given Socket from
+     * accept. The given SocketImplFactory is set during the accept and the
+     * consumer is invoked when the server socket and the accepted socket.
+     */
+    static void serverSocketAccept(SocketImpl impl,
+                                   Socket socket,
+                                   SocketImplFactory factory,
+                                   BiConsumer<ServerSocket, Socket> consumer)
+        throws IOException
+    {
+        Socket s1 = null;
+        Socket s2 = null;
+        try (ServerSocket ss = serverSocketToAccept(impl, socket)) {
+            s1 = new Socket(ss.getInetAddress(), ss.getLocalPort());
+            setSocketSocketImplFactory(factory);
+            try {
+                s2 = ss.accept();
+            } finally {
+                setSocketSocketImplFactory(null);
+            }
+            consumer.accept(ss, s2);
+        } finally {
+            if (s1 != null) s1.close();
+            if (s2 != null) s2.close();
+        }
+    }
+
+    /**
+     * Returns a new InetSocketAddress with the loopback interface
+     * and port 0.
+     */
+    static InetSocketAddress loopbackSocketAddress() {
+        InetAddress loopback = InetAddress.getLoopbackAddress();
+        return new InetSocketAddress(loopback, 0);
+    }
+
+    /**
+     * Returns a ServerSocket bound to a port on the loopback address
+     */
+    static ServerSocket boundServerSocket() throws IOException {
+        ServerSocket ss = new ServerSocket();
+        ss.bind(loopbackSocketAddress());
+        return ss;
+    }
+
+    /**
+     * Creates a ServerSocket that returns the given Socket from accept.
+     */
+    static ServerSocket serverSocketToAccept(Socket s) throws IOException {
+        ServerSocket ss = new ServerSocket() {
+            @Override
+            public Socket accept() throws IOException {
+                implAccept(s);
+                return s;
+            }
+        };
+        ss.bind(loopbackSocketAddress());
+        return ss;
+    }
+
+    /**
+     * Creates a ServerSocket with a SocketImpl that returns the given Socket
+     * from accept.
+     */
+    static ServerSocket serverSocketToAccept(SocketImpl impl, Socket s) throws IOException {
+        ServerSocket ss = new ServerSocket(impl) {
+            @Override
+            public Socket accept() throws IOException {
+                implAccept(s);
+                return s;
+            }
+        };
+        ss.bind(loopbackSocketAddress());
+        return ss;
+    }
+
+    /**
+     * Returns the socket's SocketImpl
+     */
+    static SocketImpl getSocketImpl(Socket s) {
+        try {
+            Field f = Socket.class.getDeclaredField("impl");
+            f.setAccessible(true);
+            return (SocketImpl) f.get(s);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    /**
+     * Returns the server socket's SocketImpl
+     */
+    static SocketImpl getSocketImpl(ServerSocket ss) {
+        try {
+            Field f = ServerSocket.class.getDeclaredField("impl");
+            f.setAccessible(true);
+            return (SocketImpl) f.get(ss);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    /**
+     * Returns the SocketImpl that the given SocketImpl delegates to
+     */
+    static SocketImpl getDelegate(SocketImpl si) {
+        try {
+            Class<?> clazz = Class.forName("java.net.DelegatingSocketImpl");
+            Field f = clazz.getDeclaredField("delegate");
+            f.setAccessible(true);
+            return (SocketImpl) f.get(si);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    /**
+     * Returns the value of a SocketImpl field
+     */
+    static <T> T get(SocketImpl si, String name) {
+        try {
+            Field f = SocketImpl.class.getDeclaredField(name);
+            f.setAccessible(true);
+            return (T) f.get(si);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    /**
+     * Sets the value of SocketImpl field
+     */
+    static void set(SocketImpl si, String name, Object value) {
+        try {
+            Field f = SocketImpl.class.getDeclaredField(name);
+            f.setAccessible(true);
+            f.set(si, value);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    /**
+     * Returns true if the SocketImpl is a PlatformSocketImpl
+     */
+    static boolean isPlatformSocketImpl(SocketImpl si) {
+        try {
+            Class<?> clazz = Class.forName("sun.net.PlatformSocketImpl");
+            return clazz.isInstance(si);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    /**
+     * Returns true if the SocketImpl is a SocksSocketImpl
+     */
+    static boolean isSocksSocketImpl(SocketImpl si) {
+        try {
+            Class<?> clazz = Class.forName("java.net.SocksSocketImpl");
+            return clazz.isInstance(si);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    /**
+     * Returns true if the SocketImpl is a HttpConnectSocketImpl
+     */
+    static boolean isHttpConnectSocketImpl(SocketImpl si) {
+        try {
+            Class<?> clazz = Class.forName("java.net.HttpConnectSocketImpl");
+            return clazz.isInstance(si);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    /**
+     * Socket.setSocketImplFactory(SocketImplFactory)
+     */
+    static void setSocketSocketImplFactory(SocketImplFactory factory) {
+        try {
+            Field f = Socket.class.getDeclaredField("factory");
+            f.setAccessible(true);
+            f.set(null, factory);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    /**
+     * ServerSocket.setSocketFactory(SocketImplFactory)
+     */
+    static void setServerSocketImplFactory(SocketImplFactory factory) {
+        try {
+            Field f = ServerSocket.class.getDeclaredField("factory");
+            f.setAccessible(true);
+            f.set(null, factory);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    /**
+     * Checks the 4 protected fields of a SocketImpl to make sure that they
+     * have been initialized.
+     */
+    static void checkFields(SocketImpl si) {
+        FileDescriptor fd = get(si, "fd");
+        InetAddress address = get(si, "address");
+        int port = get(si, "port");
+        int localport = get(si, "localport");
+        assertTrue(fd.valid() && address != null && port != 0 && localport != 0);
+    }
+
+    /**
+     * Custom SocketImpl that is layed on a SocketChannel or ServerSocketChannel
+     */
+    static class CustomSocketImpl extends SocketImpl {
+        private final boolean server;
+        private ServerSocketChannel ssc;
+        private SocketChannel sc;
+
+        CustomSocketImpl(boolean server) {
+            this.server = server;
+        }
+
+        @Override
+        protected void create(boolean stream) throws IOException {
+            if (server) {
+                ssc = ServerSocketChannel.open();
+            } else {
+                sc = SocketChannel.open();
+            }
+        }
+
+        @Override
+        protected void connect(String host, int port) throws IOException {
+            connect(new InetSocketAddress(host, port), 0);
+        }
+
+        @Override
+        protected void connect(InetAddress address, int port) throws IOException {
+            connect(new InetSocketAddress(address, port), 0);
+        }
+
+        @Override
+        protected void connect(SocketAddress remote, int timeout) throws IOException {
+            sc.connect(remote);
+            super.address = ((InetSocketAddress) remote).getAddress();
+            super.port = ((InetSocketAddress) remote).getPort();
+        }
+
+        @Override
+        protected void bind(InetAddress address, int port) throws IOException {
+            if (server) {
+                ssc.bind(new InetSocketAddress(address, port));
+                super.localport = ssc.socket().getLocalPort();
+            } else {
+                sc.bind(new InetSocketAddress(address, port));
+                super.localport = sc.socket().getLocalPort();
+            }
+            super.address = address;
+        }
+
+        @Override
+        protected void listen(int backlog) {
+            // do nothing
+        }
+
+        @Override
+        protected void accept(SocketImpl si) throws IOException {
+            SocketChannel peer = ssc.accept();
+            FileDescriptor fd;
+            try {
+                Class<?> clazz = Class.forName("sun.nio.ch.SocketChannelImpl");
+                Field f = clazz.getDeclaredField("fd");
+                f.setAccessible(true);
+                fd = (FileDescriptor) f.get(peer);
+            } catch (Exception e) {
+                throw new RuntimeException(e);
+            }
+            set(si, "fd", fd);
+            set(si, "address", peer.socket().getInetAddress());
+            set(si, "port", peer.socket().getPort());
+            set(si, "localport", peer.socket().getLocalPort());
+        }
+
+        @Override
+        protected InputStream getInputStream() {
+            throw new RuntimeException();
+        }
+
+        @Override
+        protected OutputStream getOutputStream() {
+            throw new RuntimeException();
+        }
+
+        @Override
+        protected int available() {
+            return 0;
+        }
+
+        @Override
+        protected void close() {
+        }
+
+        @Override
+        protected void sendUrgentData(int data) {
+            throw new RuntimeException();
+        }
+
+        @Override
+        public void setOption(int option, Object value) {
+            throw new RuntimeException();
+        }
+
+        @Override
+        public Object getOption(int option) {
+            throw new RuntimeException();
+        }
+    }
+}