Android 使用 HTTPS 問題解決（SSLHandshakeException）

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Android 5.0以下TLS1.x SSLHandshakeException

2016-11-30 12:17:02 -0800

Android

Android

TLSv1.x

最近把App的所有請求都換成Https,在測試的時候,部分手機發現請求失敗,失敗的異常信息如下:

javax.net.ssl.SSLHandshakeException: javax.net.ssl.SSLProtocolException: SSL handshake aborted: ssl=0x783e8e70: Failure in SSL library, usually a protocol error
error:14077102:SSL routines:SSL23_GET_SERVER_HELLO:unsupported protocol (external/openssl/ssl/s23_clnt.c:714 0x71a20cf8:0x00000000)

 該異常為握手失敗,但是為什么有的手機可以成功有的手機又失敗了呢,首先查看我們服務端接口TLS支持的版本為1.x,后來發現失敗的手機都是5.x以下的版本,推測應該是和這個有關,然后查閱官方文檔,SSLSocket中有提到TLS版本和Android SDK版本的對應表,如下:

Protocol	Supported (API Levels)	Enabled by default (API Levels)
SSLv3	1+	1+
TLSv1	1+	1+
TLSv1.1	16+	20+
TLSv1.2	16+	20+

 

通過這個表看到,TLSv1.x(1.1,1.2)Android默認從API16開始支持,而從API20開始默認可用,這就可以解釋之前為什么5.x以下手機在進行請求時失敗了。

知道問題的原因,我們就要解決,當然服務端可以支持TLSv1版本,這樣我們就都可以請求成功,但是這並不是最好的解決方法,我們當然要讓我們的App支持新的TLS協議才對。

通過官方文檔發現Cipher suites有的也是API20+支持或者默認可用,所以我們如果想支持TLSv1.x版本,可能需要給低版本添加Cipher suites,所以我們需要自定義SSLSocketFactory,自定義的SSLSocketFactory如下:

public class SSL extends SSLSocketFactory {
    private SSLSocketFactory defaultFactory;
    // Android 5.0+ (API level21) provides reasonable default settings
    // but it still allows SSLv3
    // https://developer.android.com/about/versions/android-5.0-changes.html#ssl
    static String protocols[] = null, cipherSuites[] = null;

    static {
        try {
            SSLSocket socket = (SSLSocket) SSLSocketFactory.getDefault().createSocket();
            if (socket != null) {
                /* set reasonable protocol versions */
                // - enable all supported protocols (enables TLSv1.1 and TLSv1.2 on Android <5.0)
                // - remove all SSL versions (especially SSLv3) because they're insecure now
                List<String> protocols = new LinkedList<>();
                for (String protocol : socket.getSupportedProtocols())
                    if (!protocol.toUpperCase().contains("SSL"))
                        protocols.add(protocol);
                SSL.protocols = protocols.toArray(new String[protocols.size()]);
                /* set up reasonable cipher suites */
                if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
                    // choose known secure cipher suites
                    List<String> allowedCiphers = Arrays.asList(
                            // TLS 1.2
                            "TLS_RSA_WITH_AES_256_GCM_SHA384",
                            "TLS_RSA_WITH_AES_128_GCM_SHA256",
                            "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256",
                            "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256",
                            "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384",
                            "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256",
                            "TLS_ECHDE_RSA_WITH_AES_128_GCM_SHA256",
                            // maximum interoperability
                            "TLS_RSA_WITH_3DES_EDE_CBC_SHA",
                            "TLS_RSA_WITH_AES_128_CBC_SHA",
                            // additionally
                            "TLS_RSA_WITH_AES_256_CBC_SHA",
                            "TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA",
                            "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA",
                            "TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA",
                            "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA");
                    List<String> availableCiphers = Arrays.asList(socket.getSupportedCipherSuites());
                    // take all allowed ciphers that are available and put them into preferredCiphers
                    HashSet<String> preferredCiphers = new HashSet<>(allowedCiphers);
                    preferredCiphers.retainAll(availableCiphers);
                    /* For maximum security, preferredCiphers should *replace* enabled ciphers (thus disabling
                     * ciphers which are enabled by default, but have become unsecure), but I guess for
                     * the security level of DAVdroid and maximum compatibility, disabling of insecure
                     * ciphers should be a server-side task */
                    // add preferred ciphers to enabled ciphers
                    HashSet<String> enabledCiphers = preferredCiphers;
                    enabledCiphers.addAll(new HashSet<>(Arrays.asList(socket.getEnabledCipherSuites())));
                    SSL.cipherSuites = enabledCiphers.toArray(new String[enabledCiphers.size()]);
                }
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public SSL(X509TrustManager tm) {
        try {
            SSLContext sslContext = SSLContext.getInstance("TLS");
            sslContext.init(null, (tm != null) ? new X509TrustManager[]{tm} : null, null);
            defaultFactory = sslContext.getSocketFactory();
        } catch (GeneralSecurityException e) {
            throw new AssertionError(); // The system has no TLS. Just give up.
        }
    }

    private void upgradeTLS(SSLSocket ssl) {
        // Android 5.0+ (API level21) provides reasonable default settings
        // but it still allows SSLv3
        // https://developer.android.com/about/versions/android-5.0-changes.html#ssl
        if (protocols != null) {
            ssl.setEnabledProtocols(protocols);
        }
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP && cipherSuites != null) {
            ssl.setEnabledCipherSuites(cipherSuites);
        }
    }

    @Override public String[] getDefaultCipherSuites() {
        return cipherSuites;
    }

    @Override public String[] getSupportedCipherSuites() {
        return cipherSuites;
    }

    @Override public Socket createSocket(Socket s, String host, int port, boolean autoClose) throws IOException {
        Socket ssl = defaultFactory.createSocket(s, host, port, autoClose);
        if (ssl instanceof SSLSocket)
            upgradeTLS((SSLSocket) ssl);
        return ssl;
    }

    @Override public Socket createSocket(String host, int port) throws IOException, UnknownHostException {
        Socket ssl = defaultFactory.createSocket(host, port);
        if (ssl instanceof SSLSocket)
            upgradeTLS((SSLSocket) ssl);
        return ssl;
    }

    @Override public Socket createSocket(String host, int port, InetAddress localHost, int localPort) throws IOException, UnknownHostException {
        Socket ssl = defaultFactory.createSocket(host, port, localHost, localPort);
        if (ssl instanceof SSLSocket)
            upgradeTLS((SSLSocket) ssl);
        return ssl;
    }

    @Override public Socket createSocket(InetAddress host, int port) throws IOException {
        Socket ssl = defaultFactory.createSocket(host, port);
        if (ssl instanceof SSLSocket)
            upgradeTLS((SSLSocket) ssl);
        return ssl;
    }

    @Override public Socket createSocket(InetAddress address, int port, InetAddress localAddress, int localPort) throws IOException {
        Socket ssl = defaultFactory.createSocket(address, port, localAddress, localPort);
        if (ssl instanceof SSLSocket)
            upgradeTLS((SSLSocket) ssl);
        return ssl;
    }
}

然后我們只需要給我們的請求設置這個SSLSocketFactory就可以了,我們以okhttp為例,如下:

//定義一個信任所有證書的TrustManager
final X509TrustManager trustAllCert = new X509TrustManager() {
    @Override
    public void checkClientTrusted(java.security.cert.X509Certificate[] chain, String authType) throws CertificateException {
    }

    @Override
    public void checkServerTrusted(java.security.cert.X509Certificate[] chain, String authType) throws CertificateException {
    }

    @Override
    public java.security.cert.X509Certificate[] getAcceptedIssuers() {
        return new java.security.cert.X509Certificate[]{};
    }
};
//設置OkHttpClient
OkHttpClient client = new OkHttpClient.Builder().sslSocketFactory(new SSL(trustAllCert), trustAllCert).build();

設置之后,用低版本手機測試Https,現在可以測試成功了。