Android 是否更改了 API 24 中的 SSL 配置？

Question

当我的 Android 23 项目尝试通过 HTTPS 连接到我的服务器时，一切正常。

如果我将目标 SDK 切换到 24，我会收到以下错误：

 javax.net.ssl.SSLHandshakeException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.
     at com.android.org.conscrypt.OpenSSLSocketImpl.startHandshake(OpenSSLSocketImpl.java:361)
     at android.net.SSLCertificateSocketFactory.verifyHostname(SSLCertificateSocketFactory.java:198)
     at android.net.SSLCertificateSocketFactory.createSocket(SSLCertificateSocketFactory.java:443)
     at org.apache.http.conn.ssl.SSLSocketFactory.createSocket(SSLSocketFactory.java:394)
     at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:170)
     at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:169)
     at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:124)
     at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:366)
     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:560)
     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:492)
     at com.worklight.wlclient.WLRequestSender.run(WLRequestSender.java:47)
     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
     at java.lang.Thread.run(Thread.java:761)
 Caused by: java.security.cert.CertificateException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.
     at com.android.org.conscrypt.TrustManagerImpl.verifyChain(TrustManagerImpl.java:563)
     at com.android.org.conscrypt.TrustManagerImpl.checkTrustedRecursive(TrustManagerImpl.java:444)
     at com.android.org.conscrypt.TrustManagerImpl.checkTrustedRecursive(TrustManagerImpl.java:508)
     at com.android.org.conscrypt.TrustManagerImpl.checkTrustedRecursive(TrustManagerImpl.java:508)
     at com.android.org.conscrypt.TrustManagerImpl.checkTrusted(TrustManagerImpl.java:401)
     at com.android.org.conscrypt.TrustManagerImpl.checkTrusted(TrustManagerImpl.java:375)
     at com.android.org.conscrypt.TrustManagerImpl.getTrustedChainForServer(TrustManagerImpl.java:304)
     at android.security.net.config.NetworkSecurityTrustManager.checkServerTrusted(NetworkSecurityTrustManager.java:94)
     at android.security.net.config.RootTrustManager.checkServerTrusted(RootTrustManager.java:88)
     at com.android.org.conscrypt.Platform.checkServerTrusted(Platform.java:178)
     at com.android.org.conscrypt.OpenSSLSocketImpl.verifyCertificateChain(OpenSSLSocketImpl.java:596)
     at com.android.org.conscrypt.NativeCrypto.SSL_do_handshake(Native Method)
     at com.android.org.conscrypt.OpenSSLSocketImpl.startHandshake(OpenSSLSocketImpl.java:357)
    ... 13 more
 Caused by: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.

切换回 23，它又可以工作了。
24 年关于证书的最低要求有什么变化吗？

Answer 1

如果您的targetSdkVersion 是 24+，则默认情况下不会在 Android 7.0 上合并用户通过设置应用安装的证书：

默认情况下，来自所有应用的安全（例如 TLS、HTTPS）连接都信任预安装的系统 CA，而面向 API 级别 23 (Android M) 及以下的应用也默认信任用户添加的 CA 商店。

（来自the network security configuration docs）

要解决这个问题，您需要定义一个network security configuration XML 资源：

<?xml version="1.0" encoding="utf-8"?>

<network-security-config>
    <base-config>
        <trust-anchors>
            <certificates src="system"/>
            <certificates src="user"/>
        </trust-anchors>
    </base-config>
</network-security-config>

然后，从清单中 <application> 元素中的 android:networkSecurityConfig 属性指向该 XML 资源。

---

一般来说，Android 7.0 通过网络安全配置子系统（android.security.net.config.RootTrustManager 和堆栈跟踪中的 kin）路由 HTTPS。这里可能还引入了与targetSdkVersion 相关的其他兼容性问题。因此，如果缺少用户证书不是您的问题，您可以创建一个重现问题的示例项目file an issue。由于我维护a backport of that stuff，因此我有兴趣了解任何错误。 :-)