较低的Android API上的SSL TrustManager设置

时间:2013-09-10 08:24:07

标签: android ssl httpsurlconnection

我有一个与HTTPS RPC通信的应用程序 HTTP服务器正在使用CAcert签名证书。

我正在使用自定义TrustManager来验证证书。

  • 因为我无法确定,CAcert包含在所有设备的可信密钥库中。
  • 因为我只想让CAcert为此连接签署证书。

但是,我正在关注Google的best practices。 我唯一改变的是:

  • 从静态字节[]而不是文件
  • 加载CAcert根证书
  • 将示例代码加载文件的最后一部分替换为HttpsURLConnection.setDefaultSSLSocketFactory(sslContext.getSocketFactory());。 UrlConnection上有一个JSONRPC2 API。

测试设备:

  • 致力于运行API18 / CM10.2的Nexus 4 / mako
  • 使用API​​18模拟器
  • 使用API​​17模拟器
  • 使用API​​14模拟器
  • 在运行API10 / CM7的HTC G2上
  • 无法正常工作。*
  • 在API8模拟器上
  • 无法正常工作

在低API设备上,它无法在SSL握手期间验证证书 尝试在API18上使用此https://google.com加载TrustManager时,它会按预期失败,因为找不到信任锚。
所以基本上,这段代码应该可行,所有方法都是API1 ...
我知道,UrlConnection在一些较低的API上被破坏了。

我该如何解决这个问题?

代码:

/**
 * Trust only CAcert's CA. CA cert is injected as byte[]. Following best practices from
 * https://developer.android.com/training/articles/security-ssl.html#UnknownCa
 */
private static void trustCAcert() {
    try {
        // Load CAs from an InputStream
        CertificateFactory cf = CertificateFactory.getInstance("X.509");

        ByteArrayInputStream is = new ByteArrayInputStream(CACERTROOTDER);

        Certificate ca;
        try {
            ca = cf.generateCertificate(is);
            Log.d(TAG, "ca=", ((X509Certificate) ca).getSubjectDN());
        } finally {
            is.close();
        }

        // Create a KeyStore containing our trusted CAs
        String keyStoreType = KeyStore.getDefaultType();
        KeyStore keyStore = KeyStore.getInstance(keyStoreType);
        keyStore.load(null, null);
        keyStore.setCertificateEntry("ca", ca);

        // Create a TrustManager that trusts the CAs in our KeyStore
        String tmfAlgorithm = TrustManagerFactory.getDefaultAlgorithm();
        TrustManagerFactory tmf = TrustManagerFactory.getInstance(tmfAlgorithm);
        tmf.init(keyStore);

        // Create an SSLContext that uses our TrustManager
        SSLContext sslContext = SSLContext.getInstance("TLS");
        sslContext.init(null, tmf.getTrustManagers(), null);

        HttpsURLConnection.setDefaultSSLSocketFactory(
            sslContext.getSocketFactory());

        // added for testing only
        URL u = new URL(
            "https://myremoteapiurlsignedwiththesamecert.com/v1/doc.html");
        HttpsURLConnection con = (HttpsURLConnection) u.openConnection();
        con.setSSLSocketFactory(sslContext.getSocketFactory());
        BufferedReader r = new BufferedReader(
            new InputStreamReader(
                con.getInputStream())); // the exception is thrown here
        // because verification fails
        String l;
        while ((l = r.readLine()) != null) {
            Log.d(TAG, "l: ", l);
        }
    } catch (IOException e) { // none of the exceptions is thrown during setup
        Log.e(TAG, "IOException", e);
    } catch (CertificateException e) {
        Log.e(TAG, "CertificateException", e);
    } catch (NoSuchAlgorithmException e) {
        Log.e(TAG, "NoSuchAlgorithmException", e);
    } catch (KeyStoreException e) {
        Log.e(TAG, "KeyStoreException", e);
    } catch (KeyManagementException e) {
        Log.e(TAG, "KeyManagementException", e);
    }
}

日志:

APIUtils  D  ca=OID.1.2.840.113549.1.9.1=#1612737570706F7274406361636572742E6F7267, CN=CA Cert Signing Authority, OU=http://www.cacert.org, O=Root CA
          E  IOException
          E  javax.net.ssl.SSLException: Not trusted server certificate
          E         at org.apache.harmony.xnet.provider.jsse.OpenSSLSocketImpl.startHandshake(OpenSSLSocketImpl.java:371)
          E         at org.apache.harmony.luni.internal.net.www.protocol.http.HttpConnection.getSecureSocket(HttpConnection.java:168)
          E         at org.apache.harmony.luni.internal.net.www.protocol.https.HttpsURLConnectionImpl$HttpsEngine.connect(HttpsURLConnectionImpl.java:399)
          E         at org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:1152)
          E         at org.apache.harmony.luni.internal.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:253)
          E         at de.terminbuddy.android.network.APIUtils.trustCAcert(APIUtils.java:294)
          E         at de.terminbuddy.android.network.APIUtils.initRpcSession(APIUtils.java:243)
          E         at de.terminbuddy.android.network.APIUtils.runRPC(APIUtils.java:323)
          E         at de.terminbuddy.android.network.AsyncJSONRPCTask.doInBackground(AsyncJSONRPCTask.java:55)
          E         at de.terminbuddy.android.network.AsyncJSONRPCTask.doInBackground(AsyncJSONRPCTask.java:17)
          E         at android.os.AsyncTask$2.call(AsyncTask.java:185)
          E         at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
          E         at java.util.concurrent.FutureTask.run(FutureTask.java:137)
          E         at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
          E         at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
          E         at java.lang.Thread.run(Thread.java:1096)
          E  Caused by: java.security.cert.CertificateException: java.security.cert.CertPathValidatorException: Could not validate certificate signature.
          E         at org.apache.harmony.xnet.provider.jsse.TrustManagerImpl.checkServerTrusted(TrustManagerImpl.java:168)
          E         at org.apache.harmony.xnet.provider.jsse.OpenSSLSocketImpl.startHandshake(OpenSSLSocketImpl.java:366)
          E         ... 15 more
          E  Caused by: java.security.cert.CertPathValidatorException: Could not validate certificate signature.
          E         at org.bouncycastle.jce.provider.PKIXCertPathValidatorSpi.engineValidate(PKIXCertPathValidatorSpi.java:342)
          E         at java.security.cert.CertPathValidator.validate(CertPathValidator.java:202)
          E         at org.apache.harmony.xnet.provider.jsse.TrustManagerImpl.checkServerTrusted(TrustManagerImpl.java:164)
          E         ... 16 more
          E  Caused by: java.security.SignatureException: Signature was not verified.
          E         at org.apache.harmony.security.provider.cert.X509CertImpl.fastVerify(X509CertImpl.java:601)
          E         at org.apache.harmony.security.provider.cert.X509CertImpl.verify(X509CertImpl.java:544)
          E         at org.bouncycastle.jce.provider.PKIXCertPathValidatorSpi.engineValidate(PKIXCertPathValidatorSpi.java:337)
          E         ... 18 more

1 个答案:

答案 0 :(得分:2)

我找到了解决这个问题的方法:

  1. 看起来CRL验证对于CAcert证书来说是某种破坏(API< 14/11)。
  2. 涉及SNI,API< 8。
  3. 不支持

    基本上我在API< 14上运行我自己的检查,其实现位于此处:Validate X509 certificates using Java APis

    private static final byte[] CACERTROOTDER = new byte[]{
            48, -126, 7, 61, 48, -126, 5, 37, -96, 3, 2, 1, 2, 2, 1, 0,
            // ...
            };
    
    /**
     * Read x509 certificated file from byte[].
     *
     * @param bytes certificate in der format
     * @return certificate
     */
    private static X509Certificate getCertificate(final byte[] bytes)
            throws IOException, CertificateException {
        CertificateFactory cf = CertificateFactory.getInstance("X.509");
        X509Certificate ca;
        ByteArrayInputStream is = new ByteArrayInputStream(bytes);
        try {
            ca = (X509Certificate) cf.generateCertificate(is);
            Log.d(TAG, "ca=", ca.getSubjectDN());
        } finally {
            is.close();
        }
        return ca;
    }
    
    /**
     * Trust only CAcert's CA. CA cert is injected as byte[]. Following best practices from
     * https://developer.android.com/training/articles/security-ssl.html#UnknownCa
     */
    private static void trustCAcert()
            throws KeyStoreException, IOException,
            CertificateException, NoSuchAlgorithmException,
            KeyManagementException {
        // Create a KeyStore containing our trusted CAs
        String keyStoreType = KeyStore.getDefaultType();
        final KeyStore keyStore = KeyStore.getInstance(keyStoreType);
        keyStore.load(null, null);
        keyStore.setCertificateEntry("CAcert-root", getCertificate(CACERTROOTDER));
        // if your HTTPd is not sending the full chain, add class3 cert to the key store
        // keyStore.setCertificateEntry("CAcert-class3", getCertificate(CACERTCLASS3DER));
    
        // Create a TrustManager that trusts the CAs in our KeyStore
        final TrustManagerFactory tmf = TrustManagerFactory.getInstance(
                TrustManagerFactory.getDefaultAlgorithm());
        tmf.init(keyStore);
    
        // Create an SSLContext that uses our TrustManager
        SSLContext sslContext = SSLContext.getInstance("TLS");
    
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
            // may work on HC+, but there is no AVD or device to test it
            sslContext.init(null, tmf.getTrustManagers(), null);
        } else {
            // looks like CLR is broken in lower APIs. implement out own checks here :x
            // see https://stackoverflow.com/q/18713966/2331953
            HttpsURLConnection.setDefaultHostnameVerifier(new HostnameVerifier() {
                public boolean verify(final String hostname, final SSLSession session) {
                    try {
                        // check if hostname matches DN
                        String dn = session.getPeerCertificateChain()[0].getSubjectDN().toString();
    
                        Log.d(TAG, "DN=", dn);
                        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.GINGERBREAD) {
                            return dn.equals("CN=" + hostname);
                        } else {
                            // no SNI on API<9, but I know the first vhost's hostname
                            return dn.equals("CN=" + hostname)
                                    || dn.equals("CN=" + hostname.replace("jsonrpc", "rest"));
                        }
                    } catch (Exception e) {
                        Log.e(TAG, "unexpected exception", e);
                        return false;
                    }
                }
            });
    
            // build our own trust manager
            X509TrustManager tm = new X509TrustManager() {
                public X509Certificate[] getAcceptedIssuers() {
                    // nothing to do
                    return new X509Certificate[0];
                }
    
                @Override
                public void checkClientTrusted(final X509Certificate[] chain,
                        final String authType)
                        throws CertificateException {
                    // nothing to do
                }
    
                @Override
                public void checkServerTrusted(final X509Certificate[] chain,
                        final String authType) throws CertificateException {
                    // nothing to do
                    Log.d(TAG, "checkServerTrusted(", chain, ")");
                    X509Certificate cert = chain[0];
    
                    cert.checkValidity();
    
                    CertificateFactory cf = CertificateFactory.getInstance("X.509");
                    ArrayList<X509Certificate> list = new ArrayList<X509Certificate>();
                    list.add(cert);
                    CertPath cp = cf.generateCertPath(list);
                    try {
                        PKIXParameters params = new PKIXParameters(keyStore);
                        params.setRevocationEnabled(false); // CLR is broken, remember?
                        CertPathValidator cpv = CertPathValidator
                                .getInstance(CertPathValidator.getDefaultType());
                        cpv.validate(cp, params);
                    } catch (KeyStoreException e) {
                        Log.d(TAG, "invalid key store", e);
                        throw new CertificateException(e);
                    } catch (InvalidAlgorithmParameterException e) {
                        Log.d(TAG, "invalid algorithm", e);
                        throw new CertificateException(e);
                    } catch (NoSuchAlgorithmException e) {
                        Log.d(TAG, "no such algorithm", e);
                        throw new CertificateException(e);
                    } catch (CertPathValidatorException e) {
                        Log.d(TAG, "verification failed");
                        throw new CertificateException(e);
                    }
                    Log.d(TAG, "verification successful");
                }
            };
            sslContext.init(null, new X509TrustManager[]{tm}, null);
        }
    
        HttpsURLConnection.setDefaultSSLSocketFactory(sslContext.getSocketFactory());
    }