Android 让WebView完美支持https双向认证(SSL)

时间：02-05来源：作者：点击数：35

最近做一个安全级别比较高的项目，对方要求使用HTTPS双向认证来访问web网页。双向认证在android5.0以上很好解决，但是在Android5.0以下，webviewclient中没有客户端向服务器发送证书的回调接口（回调是个隐藏函数）。

网上搜索到大概有这么几种解决方法：

1.利用反射调用隐藏函数（不太现实，这个方法为回调方法）

2.自己编译完整的class.jar(试过了，没成功，成本很大)

3.重写webview（不可能，工作量巨大）

经过上面的几种想法后来在网上高人的指点下有了第四种方法。

解决方法：拦截Webview的Request的请求，然后自己实现httpconnection捞取数据,然后返回新的WebResourceResponse给Webview。重写webviewclient中的shouldInterceptRequest方法即可。

下面我来给大家具体实现方法：

step1：生成两个证书

server.cer 服务器端证书

client.p12 客户端证书（需要记住密码加入之后的java文件中）

将这两个证书放在 android assets 文件下。

step2：重写WebViewClient引入两个证书

SslPinningWebViewClient.java

package com.cloudhome.webview_https;

import android.annotation.TargetApi;
import android.content.Context;
import android.net.Uri;
import android.util.Base64;
import android.util.Log;
import android.webkit.WebResourceRequest;
import android.webkit.WebResourceResponse;
import android.webkit.WebView;
import android.webkit.WebViewClient;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.security.KeyManagementException;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.UnrecoverableKeyException;
import java.security.cert.CertPathValidatorException;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;

import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.KeyManager;
import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLHandshakeException;
import javax.net.ssl.TrustManager;
import javax.net.ssl.TrustManagerFactory;
import javax.net.ssl.X509TrustManager;

/**
 * Created by mennomorsink on 06/05/15.
 */
public class SslPinningWebViewClient extends WebViewClient {

    private LoadedListener listener;
    private SSLContext sslContext;

    public SslPinningWebViewClient(LoadedListener listener)throws IOException  {
        this.listener = listener;

        prepareSslPinning(MyApplication.mContext.getResources().getAssets().open("server.cer"));
    }

    @Override
    public WebResourceResponse shouldInterceptRequest (final WebView view, String url) {
        if(MainActivity.pinningSwitch.isChecked()) {
            return processRequest(Uri.parse(url));
        } else {
            return null;
        }
    }

    @Override
    @TargetApi(21)
    public WebResourceResponse shouldInterceptRequest (final WebView view, WebResourceRequest interceptedRequest) {
        if(MainActivity.pinningSwitch.isChecked()) {
            return processRequest(interceptedRequest.getUrl());
        } else {
            return null;
        }
    }

    private WebResourceResponse processRequest(Uri uri) {
        Log.d("SSL_PINNING_WEBVIEWS", "GET: " + uri.toString());

        try {
            // Setup connection
            URL url = new URL(uri.toString());
            HttpsURLConnection urlConnection = (HttpsURLConnection) url.openConnection();

            // Set SSL Socket Factory for this request
            urlConnection.setSSLSocketFactory(sslContext.getSocketFactory());

            // Get content, contentType and encoding
            InputStream is = urlConnection.getInputStream();
            String contentType = urlConnection.getContentType();
            String encoding = urlConnection.getContentEncoding();

            // If got a contentType header
            if(contentType != null) {

                String mimeType = contentType;

                // Parse mime type from contenttype string
                if (contentType.contains(";")) {
                    mimeType = contentType.split(";")[0].trim();
                }

                Log.d("SSL_PINNING_WEBVIEWS", "Mime: " + mimeType);

                listener.Loaded(uri.toString());

                // Return the response
                return new WebResourceResponse(mimeType, encoding, is);
            }

        } catch (SSLHandshakeException e) {
            if(isCause(CertPathValidatorException.class, e)) {
                listener.PinningPreventedLoading(uri.getHost());
            }
            Log.d("SSL_PINNING_WEBVIEWS", e.getLocalizedMessage());
        } catch (Exception e) {
            Log.d("SSL_PINNING_WEBVIEWS", e.getLocalizedMessage());
        }

        // Return empty response for this request
        return new WebResourceResponse(null, null, null);
    }

    private void prepareSslPinning(InputStream... certificates)throws IOException {

        try {



            InputStream inputStream = MyApplication.mContext.getResources().getAssets().open("client.p12");

            TrustManager[] trustManagers = prepareTrustManager(certificates);
            KeyManager[] keyManagers = prepareKeyManager(inputStream, "your client.p12 password");

            sslContext = SSLContext.getInstance("TLS");

            sslContext.init(keyManagers, new TrustManager[]{new MyTrustManager(chooseTrustManager(trustManagers))}, new SecureRandom());


        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (KeyStoreException e) {
            e.printStackTrace();
        } catch (KeyManagementException e) {
            e.printStackTrace();
        }
    }




    private static TrustManager[] prepareTrustManager(InputStream... certificates)
    {
        if (certificates == null || certificates.length <= 0) return null;
        try
        {

            CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");
            KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
            keyStore.load(null);
            int index = 0;
            for (InputStream certificate : certificates)
            {
                String certificateAlias = Integer.toString(index++);
                keyStore.setCertificateEntry(certificateAlias, certificateFactory.generateCertificate(certificate));
                try
                {
                    if (certificate != null)
                        certificate.close();
                } catch (IOException e)

                {
                }
            }
            TrustManagerFactory trustManagerFactory = null;

            trustManagerFactory = TrustManagerFactory.
                    getInstance(TrustManagerFactory.getDefaultAlgorithm());
            trustManagerFactory.init(keyStore);

            TrustManager[] trustManagers = trustManagerFactory.getTrustManagers();

            return trustManagers;
        } catch (NoSuchAlgorithmException e)
        {
            e.printStackTrace();
        } catch (CertificateException e)
        {
            e.printStackTrace();
        } catch (KeyStoreException e)
        {
            e.printStackTrace();
        } catch (Exception e)
        {
            e.printStackTrace();
        }
        return null;

    }

    private static KeyManager[] prepareKeyManager(InputStream bksFile, String password)
    {
        try
        {
            if (bksFile == null || password == null) return null;

            KeyStore clientKeyStore = KeyStore.getInstance("PKCS12");
            clientKeyStore.load(bksFile, password.toCharArray());
            KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm());
            keyManagerFactory.init(clientKeyStore, password.toCharArray());
            return keyManagerFactory.getKeyManagers();

        } catch (KeyStoreException e)
        {
            e.printStackTrace();
        } catch (NoSuchAlgorithmException e)
        {
            e.printStackTrace();
        } catch (UnrecoverableKeyException e)
        {
            e.printStackTrace();
        } catch (CertificateException e)
        {
            e.printStackTrace();
        } catch (IOException e)
        {
            e.printStackTrace();
        } catch (Exception e)
        {
            e.printStackTrace();
        }
        return null;
    }

    private static X509TrustManager chooseTrustManager(TrustManager[] trustManagers)
    {
        for (TrustManager trustManager : trustManagers)
        {
            if (trustManager instanceof X509TrustManager)
            {
                return (X509TrustManager) trustManager;
            }
        }
        return null;
    }


    private static class MyTrustManager implements X509TrustManager
    {
        private X509TrustManager defaultTrustManager;
        private X509TrustManager localTrustManager;

        public MyTrustManager(X509TrustManager localTrustManager) throws NoSuchAlgorithmException, KeyStoreException
        {
            TrustManagerFactory var4 = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
            var4.init((KeyStore) null);
            defaultTrustManager = chooseTrustManager(var4.getTrustManagers());
            this.localTrustManager = localTrustManager;
        }


        @Override
        public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException
        {

        }

        @Override
        public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException
        {
            try
            {
                defaultTrustManager.checkServerTrusted(chain, authType);
            } catch (CertificateException ce)
            {
                localTrustManager.checkServerTrusted(chain, authType);
            }
        }


        @Override
        public X509Certificate[] getAcceptedIssuers()
        {
            return new X509Certificate[0];
        }
    }

    public static boolean isCause(
            Class<? extends Throwable> expected,
            Throwable exc
    ) {
        return expected.isInstance(exc) || (
                exc != null && isCause(expected, exc.getCause())
        );
    }
}

step3：重写的WebViewClient ：SslPinningWebViewClient加入到webview中

package com.cloudhome.webview_https;

import android.content.Context;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.webkit.WebView;
import android.widget.Button;
import android.widget.Switch;
import android.widget.TextView;

import java.io.IOException;

public class MainActivity extends AppCompatActivity {

    private WebView webView;
    public static Switch pinningSwitch;
    private Button btnA;
    private Button btnB;
    public static TextView textView;

    private String url1 = "your https url";
    private String url2 = "your https url";

    public MainActivity() {
    }
    public static Context mContext;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        webView = (WebView)findViewById(R.id.webView);
        webView.getSettings().setJavaScriptEnabled(true);

        pinningSwitch = (Switch)findViewById(R.id.pinningSwitch);
        btnA = (Button)findViewById(R.id.btn1);
        btnB = (Button)findViewById(R.id.btn2);
        textView = (TextView)findViewById(R.id.textView);

        mContext=this;
        SslPinningWebViewClient webViewClient = null;
        try {
            webViewClient = new SslPinningWebViewClient(new LoadedListener() {
                @Override
                public void Loaded(final String url) {
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            textView.setText("Loaded " + url);
                        }
                    });
                }

                @Override
                public void PinningPreventedLoading(final String host) {
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            textView.setText("SSL Pinning prevented loading from " + host);
                        }
                    });
                }
            });
        } catch (IOException e) {
            e.printStackTrace();
        }
        webView.setWebViewClient(webViewClient);

        btnA.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v) {
                 webView.clearView();
                 textView.setText("");
                 webView.loadUrl(url1);
             }
         });

        btnB.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                webView.clearView();
                textView.setText("");
                webView.loadUrl(url2);
            }
        });
    }
}

step4：下载回调监听借口LoadedListener借口（根据实际情况使用）

package com.cloudhome.webview_https;

/**
 * Created by mennomorsink on 25/07/15.
 */
public interface LoadedListener {
    void Loaded(String url);
    void PinningPreventedLoading(String host);
}