來自 google 的接口 X509TrustManager 的不安全實現

Question

我在 Google Play 中有一個應用程序，我收到了一封來自 Google 的郵件，內容是：

您在本電子郵件末尾列出的應用程序使用了接口 X509TrustManager 的不安全實現。 具體來說，該實現在與遠程主機建立 HTTPS 連接時會忽略所有 SSL 證書驗證錯誤，從而使您的應用容易受到中間人攻擊。

要正確處理 SSL 證書驗證，請更改自定義 X509TrustManager 接口的 checkServerTrusted 方法中的代碼，以在服務器提供的證書不符合您的期望時引發 CertificateException 或 IllegalArgumentException。

我的應用程序使用“https”，我的checkServerTrusted()如下：

 TrustManager tm = new X509TrustManager() {
        public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
        }

        public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {

        }

        public X509Certificate[] getAcceptedIssuers() {
            return null;
        }
    };

然后我修改這個函數：

 TrustManager tm = new X509TrustManager() {
        public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
        }

        public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
            if (chain == null) {
                throw new IllegalArgumentException("checkServerTrusted: X509Certificate array is null");
            }

            if (!(chain.length > 0)) {
                throw new IllegalArgumentException("checkServerTrusted: X509Certificate is empty");
            }

            if (!(null != authType && authType.equalsIgnoreCase("RSA"))) {

                throw new CertificateException("checkServerTrusted: AuthType is not RSA");
            }
        }

        public X509Certificate[] getAcceptedIssuers() {
            return null;
        }

自定義 SSLSocketFactory：

public class MySSLSocketFactory extends SSLSocketFactory {
SSLContext sslContext = SSLContext.getInstance("TLS");

public MySSLSocketFactory(KeyStore ctx) throws NoSuchAlgorithmException, KeyManagementException, KeyStoreException, UnrecoverableKeyException {
    super(ctx);

    TrustManager tm = new X509TrustManager() {
        public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
        }

        public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
        }

        public X509Certificate[] getAcceptedIssuers() {
            return null;
        }
    };

    sslContext.init(null, new TrustManager[]{tm}, null);
}

@Override
public Socket createSocket(Socket socket, String host, int port, boolean autoClose) throws IOException, UnknownHostException {
    return sslContext.getSocketFactory().createSocket(socket, host, port, autoClose);
}

@Override
public Socket createSocket() throws IOException {
    return sslContext.getSocketFactory().createSocket();
}

}

HttpClient 函數：

private static HttpClient getHttpClient(int timeout) {
    if (null == mHttpClient) {

        try {
            KeyStore trustStore = KeyStore.getInstance(KeyStore
                    .getDefaultType());
            trustStore.load(null, null);
            SSLSocketFactory sf = new MySSLSocketFactory(trustStore);
            sf.setHostnameVerifier(SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER); 

            HttpParams params = new BasicHttpParams();

            HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
            HttpProtocolParams.setContentCharset(params,
                    HTTP.DEFAULT_CONTENT_CHARSET);
            HttpProtocolParams.setUseExpectContinue(params, true);


            ConnManagerParams.setTimeout(params, timeout);

            HttpConnectionParams.setConnectionTimeout(params, timeout);

            HttpConnectionParams.setSoTimeout(params, timeout);


            SchemeRegistry schReg = new SchemeRegistry();
            schReg.register(new Scheme("http", PlainSocketFactory
                    .getSocketFactory(), 80));
            schReg.register(new Scheme("https", sf, 443));

            ClientConnectionManager conManager = new ThreadSafeClientConnManager(
                    params, schReg);

            mHttpClient = new DefaultHttpClient(conManager, params);
        } catch (Exception e) {
            e.printStackTrace();
            return new DefaultHttpClient();
        }
    }
    return mHttpClient;
}

但是我對此不太了解，我只是根據電子郵件所說的內容修改了我的代碼，我想我沒有解決這個問題。這個警告​​是關於什么的？ 如何解決？

Answer 1

我找到了這個解決方案，效果很好！

X509信任管理器：

public class EasyX509TrustManager
    implements X509TrustManager {

private X509TrustManager standardTrustManager = null;

/**
 * Constructor for EasyX509TrustManager.
 */
public EasyX509TrustManager(KeyStore keystore)
        throws NoSuchAlgorithmException, KeyStoreException {
    super();
    TrustManagerFactory factory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
    factory.init(keystore);
    TrustManager[] trustmanagers = factory.getTrustManagers();
    if (trustmanagers.length == 0) {
        throw new NoSuchAlgorithmException("no trust manager found");
    }
    this.standardTrustManager = (X509TrustManager) trustmanagers[0];
}

/**
 * @see X509TrustManager#checkClientTrusted(X509Certificate[], String authType)
 */
public void checkClientTrusted(X509Certificate[] certificates, String authType)
        throws CertificateException {
    standardTrustManager.checkClientTrusted(certificates, authType);
}

/**
 * @see X509TrustManager#checkServerTrusted(X509Certificate[], String authType)
 */
public void checkServerTrusted(X509Certificate[] certificates, String authType)
        throws CertificateException {
    if ((certificates != null) && (certificates.length == 1)) {
        certificates[0].checkValidity();
    } else {
        standardTrustManager.checkServerTrusted(certificates, authType);
    }
}

/**
 * @see X509TrustManager#getAcceptedIssuers()
 */
public X509Certificate[] getAcceptedIssuers() {
    return this.standardTrustManager.getAcceptedIssuers();
}

}

SSLSocketFactory：

public class EasySSLSocketFactory implements LayeredSocketFactory {

private SSLContext sslcontext = null;

private static SSLContext createEasySSLContext() throws IOException {
    try {
        SSLContext context = SSLContext.getInstance("TLS");
        context.init(null, new TrustManager[]{new EasyX509TrustManager(
                null)}, null);
        return context;
    } catch (Exception e) {
        throw new IOException(e.getMessage());
    }
}

private SSLContext getSSLContext() throws IOException {
    if (this.sslcontext == null) {
        this.sslcontext = createEasySSLContext();
    }
    return this.sslcontext;
}

/**
 * @see org.apache.http.conn.scheme.SocketFactory#connectSocket(Socket,
 * String, int, InetAddress, int,
 * HttpParams)
 */
public Socket connectSocket(Socket sock, String host, int port,
                            InetAddress localAddress, int localPort, HttpParams params)
        throws IOException, UnknownHostException, ConnectTimeoutException {
    int connTimeout = HttpConnectionParams.getConnectionTimeout(params);
    int soTimeout = HttpConnectionParams.getSoTimeout(params);

    InetSocketAddress remoteAddress = new InetSocketAddress(host, port);
    SSLSocket sslsock = (SSLSocket) ((sock != null) ? sock : createSocket());

    if ((localAddress != null) || (localPort > 0)) {
        // we need to bind explicitly
        if (localPort < 0) {
            localPort = 0; // indicates "any"
        }
        InetSocketAddress isa = new InetSocketAddress(localAddress,
                localPort);
        sslsock.bind(isa);
    }

    sslsock.connect(remoteAddress, connTimeout);
    sslsock.setSoTimeout(soTimeout);
    return sslsock;

}

/**
 * @see org.apache.http.conn.scheme.SocketFactory#createSocket()
 */
public Socket createSocket() throws IOException {
    return getSSLContext().getSocketFactory().createSocket();
}

/**
 * @see org.apache.http.conn.scheme.SocketFactory#isSecure(Socket)
 */
public boolean isSecure(Socket socket) throws IllegalArgumentException {
    return true;
}

/**
 * @see LayeredSocketFactory#createSocket(Socket,
 * String, int, boolean)
 */
public Socket createSocket(Socket socket, String host, int port,
                           boolean autoClose) throws IOException, UnknownHostException {
    return getSSLContext().getSocketFactory().createSocket(socket, host, port, autoClose);
}

// -------------------------------------------------------------------
// javadoc in org.apache.http.conn.scheme.SocketFactory says :
// Both Object.equals() and Object.hashCode() must be overridden
// for the correct operation of some connection managers
// -------------------------------------------------------------------

public boolean equals(Object obj) {
    return ((obj != null) && obj.getClass().equals(
            EasySSLSocketFactory.class));
}

public int hashCode() {
    return EasySSLSocketFactory.class.hashCode();
}

}

然后：

SchemeRegistry schReg = new SchemeRegistry();
            schReg.register(new Scheme("http", PlainSocketFactory
                    .getSocketFactory(), 80));
            schReg.register(new Scheme("https", new EasySSLSocketFactory(), 443));

Answer 2

您提議的修改並未修復安全漏洞。 無論有效性如何，您的代碼仍將接受任何格式正確的證書。

如果您不確定如何正確驗證證書，您應該刪除自定義信任管理器。 除非你正在做一些不尋常的事情，否則你不需要一個。

Answer 3

最簡單的方法是不提供自己的自定義TrustManager 。 只需使用默認的TrustManager ，它就會為您進行公鑰（ X.509 ）驗證和驗證。

Answer 4

僅使用默認的 X509trustmanager 方法 checkServerTrusted(chain, authType) ，它們將適當地處理所有驗證。