java - SSLServerSocket 和证书设置

Question

我使用 ServerSocket 和 Socket 对象编写了一个客户端/服务器 Java 程序。然后，我修改了代码以使用 SSLServerSocket 和“SSLSocket”，但是我抛出了不同的异常，包括:

javax.net.ssl.SSLHandshakeException:没有共同的密码套件

我希望尽可能多地以编程方式进行。我也可以使用自签名证书。

我遵循的一个教程建议使用 keytool java 应用程序创建一个证书，然后将该文件移动到您的 java 项目中。我已使用终端命令 keytool -genkey -alias zastore -keyalg RSA -keystore za.store 完成此操作。我将密码指定为 password。

然后我调用函数 System.setProperty 希望 SSLSockets 工作，但它仍然没有。

这是我的服务器代码

public class Server implements Runnable
{
    private SSLServerSocket serverSocket;
    private int portNumber;
    private Thread acceptThread;

    private LinkedList<Connection> connections;

    private ConnectionListener connectionListener;

    public Server(int port, ConnectionListener connectionListener)
    {
        this.connectionListener = connectionListener;
        portNumber = port;
        connections = new LinkedList<Connection>();
        try 
        {
            System.setProperty("javax.net.ssl.trustStore", "za.store");
            System.setProperty("javax.net.ssl.keyStorePassword", "password");
            SSLServerSocketFactory sslssf = (SSLServerSocketFactory) SSLServerSocketFactory.getDefault();

            serverSocket = (SSLServerSocket) sslssf.createServerSocket(portNumber,15);

        } 
        catch (IOException e) 
        {
            e.printStackTrace();
        }
    }

    public void startListening()
    {
        acceptThread = new Thread(this);
        acceptThread.start();
    }
    public void stopListening()
    {

        for(Connection c:connections)
        {
            c.stopListeningAndDisconnect();
        }

        try 
        {   
            serverSocket.close();
        } 
        catch (IOException e) 
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    @Override
    public void run() 
    {
        try 
        {
            while(true)
            {
                SSLSocket s = (SSLSocket) serverSocket.accept();
                Connection c = new Connection(s,connectionListener);
                connections.add(c);
                System.out.println("New Connection Established From"+s.getInetAddress().toString());
            }
        } 
        catch(java.net.SocketException e)
        {
            System.out.println("Listening thread terminated with exception.");
        }
        catch(IOException e) 
        {

            e.printStackTrace();
        }
    }

    public void removeConnection(Connection c)
    {
        connections.remove(c);
    }

    public void printConnections()
    {
        System.out.println("Number of connections "+connections.toString());

        for(int i=0; i<connections.size(); i++)
        {
            System.out.println(connections.toString());
        }
    }

}

然后是按下按钮时连接的客户端代码片段:

@Override
    public void actionPerformed(ActionEvent e) 
    {
        if(e.getSource() == connect)
        {
            try 
            {
                System.setProperty("javax.net.ssl.trustStore", "za.store");
                System.setProperty("javax.net.ssl.keyStorePassword", "password");



                SSLSocketFactory sslsf = (SSLSocketFactory)SSLSocketFactory.getDefault();

                SSLSocket s = (SSLSocket)sslsf.createSocket(ipBox.getText(), Integer.parseInt(portBox.getText()));
                Connection c = new Connection(s,parent);
                parent.connectionSuccessful(c);
            } 
            catch (NumberFormatException e1) 
            {
                JOptionPane.showMessageDialog(this, "Error! Port number must be a number", "Error", JOptionPane.ERROR_MESSAGE);             
            } 
            catch (UnknownHostException e1) 
            {
                JOptionPane.showMessageDialog(this, "Error! Unable to find that host", "Error", JOptionPane.ERROR_MESSAGE);
            } 
            catch (IOException e1) 
            {


e1.printStackTrace();
        }   
    }
}

一篇 Stackoverflow 文章建议我的服务器“没有证书”。我不知道那是什么意思，也不知道如何获得一个并将其放置在正确的位置。

Answer 1

由于各种原因可能会出现以下错误:

javax.net.ssl.SSLHandshakeException: no cipher suites in common

调试时要检查的要点:

1. keystore 和信任库已正确加载并用于创建套接字连接
2. 证书与启用的密码套件兼容
3. 客户端和服务器至少应该启用一个通用密码套件，并且该密码套件也应该与证书兼容

例如在以下示例中，我使用带有默认密码套件集的 Java 8。我生成的证书使用 ECDSA 和 SHA384，因此当服务器和客户端之间建立 TLS 连接时，我可以通过启用调试 ( System.setProperty("javax.net.debug", "ssl");).

下面是一个工作示例:

第一步，需要创建 key 对和证书。出于测试目的，让我们创建一个自签名证书，并为服务器和客户端使用相同的证书:

keytool -genkeypair -alias server -keyalg EC \
-sigalg SHA384withECDSA -keysize 256 -keystore servercert.p12 \
-storetype pkcs12 -v -storepass abc123 -validity 10000 -ext san=ip:127.0.0.1

现在让我们创建服务器:

package com.sapbasu.javastudy;

import java.io.InputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.security.KeyStore;
import java.security.SecureRandom;
import java.util.Objects;

import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLServerSocket;
import javax.net.ssl.SSLServerSocketFactory;
import javax.net.ssl.TrustManagerFactory;

/*
 * keytool -genkeypair -alias server -keyalg EC \
 * -sigalg SHA384withECDSA -keysize 256 -keystore servercert.p12 \
 * -storetype pkcs12 -v -storepass abc123 -validity 10000 -ext san=ip:127.0.0.1
 */

public class TLSServer {
  public void serve(int port, String tlsVersion, String trustStoreName,
      char[] trustStorePassword, String keyStoreName, char[] keyStorePassword)
      throws Exception {

    Objects.requireNonNull(tlsVersion, "TLS version is mandatory");

    if (port <= 0) {
      throw new IllegalArgumentException(
          "Port number cannot be less than or equal to 0");
    }

    KeyStore trustStore = KeyStore.getInstance(KeyStore.getDefaultType());
    InputStream tstore = TLSServer.class
        .getResourceAsStream("/" + trustStoreName);
    trustStore.load(tstore, trustStorePassword);
    tstore.close();
    TrustManagerFactory tmf = TrustManagerFactory
        .getInstance(TrustManagerFactory.getDefaultAlgorithm());
    tmf.init(trustStore);

    KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
    InputStream kstore = TLSServer.class
        .getResourceAsStream("/" + keyStoreName);
    keyStore.load(kstore, keyStorePassword);
    KeyManagerFactory kmf = KeyManagerFactory
        .getInstance(KeyManagerFactory.getDefaultAlgorithm());
    kmf.init(keyStore, keyStorePassword);
    SSLContext ctx = SSLContext.getInstance("TLS");
    ctx.init(kmf.getKeyManagers(), tmf.getTrustManagers(),
        SecureRandom.getInstanceStrong());

    SSLServerSocketFactory factory = ctx.getServerSocketFactory();
    try (ServerSocket listener = factory.createServerSocket(port)) {
      SSLServerSocket sslListener = (SSLServerSocket) listener;

      sslListener.setNeedClientAuth(true);
      sslListener.setEnabledProtocols(new String[] {tlsVersion});
      // NIO to be implemented
      while (true) {
        try (Socket socket = sslListener.accept()) {
          PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
          out.println("Hello World!");
        } catch (Exception e) {
          e.printStackTrace();
        }
      }
    }
  }
}

现在创建客户端:

package com.sapbasu.javastudy;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.InetAddress;
import java.net.Socket;
import java.security.KeyStore;
import java.security.SecureRandom;
import java.util.Objects;

import javax.net.SocketFactory;
import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLParameters;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.TrustManagerFactory;

public class TLSClient {
  public String request(InetAddress serverHost, int serverPort,
      String tlsVersion, String trustStoreName, char[] trustStorePassword,
      String keyStoreName, char[] keyStorePassword) throws Exception {

    Objects.requireNonNull(tlsVersion, "TLS version is mandatory");

    Objects.requireNonNull(serverHost, "Server host cannot be null");

    if (serverPort <= 0) {
      throw new IllegalArgumentException(
          "Server port cannot be lesss than or equal to 0");
    }

    KeyStore trustStore = KeyStore.getInstance(KeyStore.getDefaultType());
    InputStream tstore = TLSClient.class
        .getResourceAsStream("/" + trustStoreName);
    trustStore.load(tstore, trustStorePassword);
    tstore.close();
    TrustManagerFactory tmf = TrustManagerFactory
        .getInstance(TrustManagerFactory.getDefaultAlgorithm());
    tmf.init(trustStore);

    KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
    InputStream kstore = TLSClient.class
        .getResourceAsStream("/" + keyStoreName);
    keyStore.load(kstore, keyStorePassword);
    KeyManagerFactory kmf = KeyManagerFactory
        .getInstance(KeyManagerFactory.getDefaultAlgorithm());
    kmf.init(keyStore, keyStorePassword);
    SSLContext ctx = SSLContext.getInstance("TLS");
    ctx.init(kmf.getKeyManagers(), tmf.getTrustManagers(),
        SecureRandom.getInstanceStrong());

    SocketFactory factory = ctx.getSocketFactory();

    try (Socket connection = factory.createSocket(serverHost, serverPort)) {
      ((SSLSocket) connection).setEnabledProtocols(new String[] {tlsVersion});
      SSLParameters sslParams = new SSLParameters();
      sslParams.setEndpointIdentificationAlgorithm("HTTPS");
      ((SSLSocket) connection).setSSLParameters(sslParams);

      BufferedReader input = new BufferedReader(
          new InputStreamReader(connection.getInputStream()));
      return input.readLine();
    }
  }
}

最后，这是一个用于测试连接的 JUnit 测试:

package com.sapbasu.javastudy;

import static org.junit.jupiter.api.Assertions.assertEquals;

import java.net.InetAddress;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import org.junit.jupiter.api.Test;

public class TLSServerClientTest {

  private static final int SERVER_PORT = 8444;
  private static final String TLS_VERSION = "TLSv1.2";
  private static final int SERVER_COUNT = 1;
  private static final String SERVER_HOST_NAME = "127.0.0.1";
  private static final String TRUST_STORE_NAME = "servercert.p12";
  private static final char[] TRUST_STORE_PWD = new char[] {'a', 'b', 'c', '1',
      '2', '3'};
  private static final String KEY_STORE_NAME = "servercert.p12";
  private static final char[] KEY_STORE_PWD = new char[] {'a', 'b', 'c', '1',
      '2', '3'};

  @Test
  public void whenClientSendsServerRequest_givenServerIsUp_returnsHelloWorld()
      throws Exception {
    TLSServer server = new TLSServer();
    TLSClient client = new TLSClient();

    System.setProperty("javax.net.debug", "ssl");

    ExecutorService serverExecutor = Executors.newFixedThreadPool(SERVER_COUNT);
    serverExecutor.submit(() -> {
      try {
        server.serve(SERVER_PORT, TLS_VERSION, TRUST_STORE_NAME,
            TRUST_STORE_PWD, KEY_STORE_NAME, KEY_STORE_PWD);
      } catch (Exception e) {
        e.printStackTrace();
      }
    });
    try {
      String returnedValue = client.request(
          InetAddress.getByName(SERVER_HOST_NAME), SERVER_PORT, TLS_VERSION,
          TRUST_STORE_NAME, TRUST_STORE_PWD, KEY_STORE_NAME, KEY_STORE_PWD);
      assertEquals("Hello World!", returnedValue);
    } catch (Exception e) {
      e.printStackTrace();
      throw e;
    }
  }
}

注意:证书(在此示例中为 servercert.p12)应位于类路径中。在本例中，我将其保存在 Maven 文件夹结构的 test/resources 文件夹中，以便 JUnit 测试可以在类路径中获取它。

---

密码套件背景

使用 TLS/SSL 时，要使用的加密算法由密码套件决定。服务器支持一组密码套件(您可以根据需要和所需的安全级别启用或禁用某些套件)。客户端还支持一组密码套件。在连接设置期间，要使用的密码套件在客户端和服务器之间协商。如果服务器支持该特定密码套件，则客户端首选项将得到尊重。

您会找到 Sun 提供程序支持的密码套件列表，最高支持 Java 8 here .

典型的密码套件名称如下所示:

TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256

这里，

ECDHE 代表椭圆曲线 Diffie Hellman Ephemeral。这是一个 key 交换算法。 Elliptic 变体(第一个 E)用于性能，而 Ephemeral 变体(最后一个 E)用于前向保密。前向保密意味着如果攻击者通过 TLS 记录所有通信并在稍后的某个时间点以某种方式获得私钥，他/她将无法解密过去记录的通信。

ECDSA 是一种用于对 key 进行签名的数字签名算法，用于验证(验证其完整性)共享 secret 。 ECDSA 比 HMAC 等其他身份验证算法更弱且更慢。然而它被用于共享 key 认证，因为它不需要验证者知道用于创建认证标签的 key 。服务器可以很好地使用它的私钥来验证消息的完整性。

AES_128_GCM - 一旦双方(通常是浏览器和网络服务器)共享了一个共同的 key ，对称 block 密码算法用于加密双方之间的消息交换。在这种特殊情况下，使用具有 128 位 key 和 GCM 身份验证模式的分组密码 AES。

SHA256 - PRF 的哈希算法