Netty SSL: пример клиента чата с пользовательским хранилищем ключей не может принимать несколько подключений

Я играл с примерами Netty (версия 4.0.24) SecureChatServer и подключил свое собственное хранилище ключей (на основе ответов, найденных в следующих двух сообщениях post 1 и post2. См. фрагменты кода ниже.

Проблема, которую я вижу, заключается в том, что все работает так, как ожидалось, когда я запускаю один экземпляр клиента, но когда я пытаюсь запустить больше экземпляров клиента, я получаю исключения как на сервере, так и на клиенте (см. текст исключения ниже) и в этот момент сервер перестает отвечать.

Я надеюсь, что кто-то здесь может пролить свет на то, что я делаю неправильно.

Это класс, который обрабатывает загрузку моего хранилища ключей и создание экземпляров SSLContext, используемых как клиентом, так и сервером (по понятным причинам я опустил значения хранилища ключей):

package com.test.securechat;

import java.io.ByteArrayInputStream;
import java.security.KeyStore;
import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManagerFactory;

import com.test.util.Key;
import com.pragmafs.util.encryption.Base64Coder;

/**
 * Creates SSLContext instances from a static (String representation) keystore
 * See http://maxrohde.com/2013/09/07/setting-up-ssl-with-netty/
 */
public class SslContextFactory {
    private static final String PROTOCOL = "TLS";
    private static final SSLContext SERVER_CONTEXT;
    private static final SSLContext CLIENT_CONTEXT;
    private static final TrustManagerFactory trustManagerFactory;

    static {

        SSLContext serverContext = null;
        SSLContext clientContext = null;

        try {

            KeyStore ks = KeyStore.getInstance("JKS");
            ks.load(new ByteArrayInputStream(Base64Coder.decode(Key.SSL.getKey())), Base64Coder.decodeString(Key.SSL.getPwd()).toCharArray());

            // Set up key manager factory to use our key store
            KeyManagerFactory kmf = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm());
            kmf.init(ks, Base64Coder.decodeString(Key.SSL.getPwd()).toCharArray());

            // truststore
            KeyStore ts = KeyStore.getInstance("JKS");
            ts.load(new ByteArrayInputStream(Base64Coder.decode(Key.SSL.getKey())), Base64Coder.decodeString(Key.SSL.getPwd()).toCharArray());

            // set up trust manager factory to use our trust store
            trustManagerFactory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
            trustManagerFactory.init(ts);

            // Initialize the SSLContext to work with our key managers.
            serverContext = SSLContext.getInstance(PROTOCOL);
            serverContext.init(kmf.getKeyManagers(), trustManagerFactory.getTrustManagers(), null);

            clientContext = SSLContext.getInstance(PROTOCOL);
            clientContext.init(null, trustManagerFactory.getTrustManagers(), null);
        } catch (Exception e) {
            throw new Error("Failed to initialize the SSLContext", e);
        }

        SERVER_CONTEXT = serverContext;
        CLIENT_CONTEXT = clientContext;
    }


    public static SSLContext getServerContext() {
        return SERVER_CONTEXT;
    }

    public static SSLContext getClientContext() {
        return CLIENT_CONTEXT;
    }

    public static TrustManagerFactory getTrustManagerFactory() {
        return trustManagerFactory;
    }

    private SslContextFactory() {
        // Unused
    }
}

Это код сервера:

package com.test.securechat;

import java.net.InetAddress;
import javax.net.ssl.SSLEngine;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.channel.group.ChannelGroup;
import io.netty.channel.group.DefaultChannelGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.DelimiterBasedFrameDecoder;
import io.netty.handler.codec.Delimiters;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.ssl.SslHandler;
import io.netty.util.concurrent.Future;
import io.netty.util.concurrent.GenericFutureListener;
import io.netty.util.concurrent.GlobalEventExecutor;


/**
 * Simple SSL chat server
 */
public final class SecureChatServer {

    static final int PORT = Integer.parseInt(System.getProperty("port", "8992"));

    public static void main(String[] args) throws Exception {

        SSLEngine sslEngine = SslContextFactory.getServerContext().createSSLEngine();
        sslEngine.setUseClientMode(false);

        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .handler(new LoggingHandler(LogLevel.INFO))
                    .childHandler(new SecureChatServerInitializer(sslEngine));

            b.bind(PORT).sync().channel().closeFuture().sync();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }

    private static class SecureChatServerInitializer extends ChannelInitializer<SocketChannel> {

        private final SSLEngine sslCtx;

        public SecureChatServerInitializer(SSLEngine sslCtx) {
            this.sslCtx = sslCtx;
        }

        @Override
        public void initChannel(SocketChannel ch) throws Exception {
            ChannelPipeline pipeline = ch.pipeline();

            pipeline.addLast(new SslHandler(sslCtx));
            pipeline.addLast(new DelimiterBasedFrameDecoder(8192, Delimiters.lineDelimiter()));
            pipeline.addLast(new StringDecoder());
            pipeline.addLast(new StringEncoder());

            // and then business logic.
            pipeline.addLast(new SecureChatServerHandler());
        }
    }

    private static class SecureChatServerHandler extends SimpleChannelInboundHandler<String> {

        static final ChannelGroup channels = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);

        @Override
        public void channelActive(final ChannelHandlerContext ctx) {
            // Once session is secured, send a greeting and register the channel to the global channel
            // list so the channel received the messages from others.
            ctx.pipeline().get(SslHandler.class).handshakeFuture().addListener(
                    new GenericFutureListener<Future<Channel>>() {
                        @Override
                        public void operationComplete(Future<Channel> future) throws Exception {
                            ctx.writeAndFlush(
                                    "Welcome to " + InetAddress.getLocalHost().getHostName() + " secure chat service!\n");
                            ctx.writeAndFlush(
                                    "Your session is protected by " +
                                            ctx.pipeline().get(SslHandler.class).engine().getSession().getCipherSuite() +
                                            " cipher suite.\n");

                            channels.add(ctx.channel());
                        }
                    });
        }

        @Override
        public void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
            // Send the received message to all channels but the current one.
            for (Channel c : channels) {
                if (c != ctx.channel()) {
                    c.writeAndFlush("[" + ctx.channel().remoteAddress() + "] " + msg + '\n');
                } else {
                    c.writeAndFlush("[you] " + msg + '\n');
                }
            }

            // Close the connection if the client has sent 'bye'.
            if ("bye".equals(msg.toLowerCase())) {
                ctx.close();
            }
        }

        @Override
        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
            cause.printStackTrace();
            ctx.close();
        }
    }
}

Код клиента:

package com.test.securechat;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import javax.net.ssl.SSLEngine;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.DelimiterBasedFrameDecoder;
import io.netty.handler.codec.Delimiters;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import io.netty.handler.ssl.SslHandler;

/**
 * Simple SSL chat client
 */
public final class SecureChatClient {

    static final String HOST = System.getProperty("host", "127.0.0.1");
    static final int PORT = Integer.parseInt(System.getProperty("port", "8992"));

    public static void main(String[] args) throws Exception {

        SSLEngine engine = SslContextFactory.getClientContext().createSSLEngine();
        engine.setUseClientMode(true);

        EventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(group)
                    .channel(NioSocketChannel.class)
                    .handler(new SecureChatClientInitializer(engine));

            // Start the connection attempt.
            Channel ch = b.connect(HOST, PORT).sync().channel();

            // Read commands from the stdin.
            ChannelFuture lastWriteFuture = null;
            BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
            for (; ; ) {
                String line = in.readLine();
                if (line == null) {
                    break;
                }

                // Sends the received line to the server.
                lastWriteFuture = ch.writeAndFlush(line + "\r\n");

                // If user typed the 'bye' command, wait until the server closes
                // the connection.
                if ("bye".equals(line.toLowerCase())) {
                    ch.closeFuture().sync();
                    break;
                }
            }

            // Wait until all messages are flushed before closing the channel.
            if (lastWriteFuture != null) {
                lastWriteFuture.sync();
            }
        } finally {
            // The connection is closed automatically on shutdown.
            group.shutdownGracefully();
        }
    }

    private static class SecureChatClientInitializer extends ChannelInitializer<SocketChannel> {

        private final SSLEngine sslCtx;

        public SecureChatClientInitializer(SSLEngine sslCtx) {
            this.sslCtx = sslCtx;
        }

        @Override
        public void initChannel(SocketChannel ch) throws Exception {
            ChannelPipeline pipeline = ch.pipeline();

            // Add SSL handler first to encrypt and decrypt everything.
            // In this example, we use a bogus certificate in the server side
            // and accept any invalid certificates in the client side.
            // You will need something more complicated to identify both
            // and server in the real world.
            //pipeline.addLast(sslCtx.newHandler(ch.alloc(), SecureChatClient.HOST, SecureChatClient.PORT));
            pipeline.addLast(new SslHandler(sslCtx));

            // On top of the SSL handler, add the text line codec.
            pipeline.addLast(new DelimiterBasedFrameDecoder(8192, Delimiters.lineDelimiter()));
            pipeline.addLast(new StringDecoder());
            pipeline.addLast(new StringEncoder());
            //pipeline.addLast(new LoggingHandler(LogLevel.INFO));


            // and then business logic.
            pipeline.addLast(new SecureChatClientHandler());
        }
    }

    private static class SecureChatClientHandler extends SimpleChannelInboundHandler<String> {

        @Override
        public void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
            System.err.println(msg);
        }

        @Override
        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
            cause.printStackTrace();
            ctx.close();
        }
    }
}

Исключение сервера:

INFO: [id: 0x5eb2ac7a, /0:0:0:0:0:0:0:0:8992] RECEIVED: [id: 0x7d7a7dca, /127.0.0.1:55932 => /127.0.0.1:8992]
io.netty.handler.codec.DecoderException: javax.net.ssl.SSLHandshakeException: ciphertext sanity check failed
    at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:278)
    at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:147)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319)
    at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:787)
    at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:130)
    at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:511)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:468)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:382)
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:354)
    at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116)
    at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:137)
    at java.lang.Thread.run(Thread.java:744)
Caused by: javax.net.ssl.SSLHandshakeException: ciphertext sanity check failed
    at sun.security.ssl.Alerts.getSSLException(Alerts.java:192)
    at sun.security.ssl.SSLEngineImpl.fatal(SSLEngineImpl.java:1683)
    at sun.security.ssl.SSLEngineImpl.readRecord(SSLEngineImpl.java:959)
    at sun.security.ssl.SSLEngineImpl.readNetRecord(SSLEngineImpl.java:884)
    at sun.security.ssl.SSLEngineImpl.unwrap(SSLEngineImpl.java:758)
    at javax.net.ssl.SSLEngine.unwrap(SSLEngine.java:624)
    at io.netty.handler.ssl.SslHandler.unwrap(SslHandler.java:995)
    at io.netty.handler.ssl.SslHandler.unwrap(SslHandler.java:921)
    at io.netty.handler.ssl.SslHandler.decode(SslHandler.java:867)
    at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:247)
    ... 12 more
Caused by: javax.crypto.BadPaddingException: ciphertext sanity check failed
    at sun.security.ssl.InputRecord.decrypt(InputRecord.java:147)
    at sun.security.ssl.EngineInputRecord.decrypt(EngineInputRecord.java:192)
    at sun.security.ssl.SSLEngineImpl.readRecord(SSLEngineImpl.java:953)
    ... 19 more

Исключение клиента:

io.netty.handler.codec.DecoderException: javax.net.ssl.SSLException: Received fatal alert: <UNKNOWN ALERT: 170>
    at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:278)
    at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:147)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319)
    at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:787)
    at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:130)
    at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:511)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:468)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:382)
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:354)
    at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116)
    at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:137)
    at java.lang.Thread.run(Thread.java:744)
Caused by: javax.net.ssl.SSLException: Received fatal alert: <UNKNOWN ALERT: 170>
    at sun.security.ssl.Alerts.getSSLException(Alerts.java:208)
    at sun.security.ssl.SSLEngineImpl.fatal(SSLEngineImpl.java:1619)
    at sun.security.ssl.SSLEngineImpl.fatal(SSLEngineImpl.java:1587)
    at sun.security.ssl.SSLEngineImpl.recvAlert(SSLEngineImpl.java:1756)
    at sun.security.ssl.SSLEngineImpl.readRecord(SSLEngineImpl.java:1060)
    at sun.security.ssl.SSLEngineImpl.readNetRecord(SSLEngineImpl.java:884)
    at sun.security.ssl.SSLEngineImpl.unwrap(SSLEngineImpl.java:758)
    at javax.net.ssl.SSLEngine.unwrap(SSLEngine.java:624)
    at io.netty.handler.ssl.SslHandler.unwrap(SslHandler.java:995)
    at io.netty.handler.ssl.SslHandler.unwrap(SslHandler.java:921)
    at io.netty.handler.ssl.SslHandler.decode(SslHandler.java:867)
    at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:247)
    ... 12 more