如何更新已创建的 Wi-Fi 配置（或“UID XXX 无权更新 [Wi-Fi] 配置错误”）？

Question

我正在开发一个管理 Wi-Fi 连接的应用程序。我的场景是这样的：假设整个建筑物都有一个名为“testing-tls”的 Wi-Fi 网络。我的应用程序应该只能连接到选定的接入点（基于 BSSID 或 MAC ID）。我们使用TLS 身份验证机制来验证用户（自定义 CA 证书）。

我能够通过应用程序建立连接，但是当我尝试连接到不同的接入点（不同的 BSSID）时失败。即使我以编程方式创建了 Wi-Fi 配置，我也无法在第一次成功连接后更新配置。我已经在奥利奥和棉花糖中测试了我的应用程序。但是，我在奥利奥遇到了问题（不确定牛轧糖）。我开始怀疑是否有可能在创建后更新配置。

这些是我遵循的步骤：

1) 创建一个 WifiConfiguration 对象

private WifiConfiguration createWifiConfiguration() {
    WifiConfiguration config = new WifiConfiguration();
    config.SSID = "\"testing-tls\"";
    config.priority = 1;
    config.status = WifiConfiguration.Status.ENABLED;
    config.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_EAP;
    config.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.IEEE8021X);
    config.enterpriseConfig.setIdentity(identityName);
    config.enterpriseConfig.setEapMethod(WifiEnterpriseConfig.Eap.TLS);

    PKCS12ParseInfo parseInfo;
    try {
        parseInfo = CertificateUtils.parsePKCS12Certificate(
                       certificateFilePath, identityPassword);
        if (parseInfo != null) {
            config.enterpriseConfig.setClientKeyEntry(parseInfo.getPrivateKey(),
                           parseInfo.getCertificate());
            return config;
        }
        return null;
    } catch (KeyStoreException | NoSuchAlgorithmException | IOException |
                   CertificateException | UnrecoverableKeyException | KeyManagementException e1) {
        Timber.e("WifiMonitorService, Fail to parse the input certificate: %s", e1.toString());
        Toast.makeText(this, "Error occurred", Toast.LENGTH_SHORT).show();
        return null;
    }
}

2）尝试建立连接

private void establishWifiConnection(String result) {
    Timber.d("WifiMonitorService, establishing WifiConnection");

    WifiConfiguration configuration = createWifiConfiguration();
    if (configuration != null) {
        // result contains a mac id - 00:45:69:c5:34:f2
        configuration.BSSID = result;

        int networkId = wifiManager.addNetwork(configuration);
        if (networkId == -1) {
            networkId = getExistingNetworkId(wifiSsid);
            // Add a new configuration to the db
            if (networkId == -1) {
                Timber.e("Couldn't add network with SSID");
                Toast.makeText(this, "Wifi configuration error", Toast.LENGTH_SHORT).show();
                return;
            }
        }
        Timber.i("WifiMonitorService, # addNetwork returned: %d", networkId);
        wifiManager.saveConfiguration();
        wifiManager.enableNetwork(networkId, true);
        wifiManager.reassociate();
    } else {
        Toast.makeText(this, "Wifi conf Error occurred", Toast.LENGTH_SHORT).show();
    }
}

3) 获取退出网络 ID（如果存在）

private int getExistingNetworkId(String ssid) {
    List<WifiConfiguration> configuredNetworks  = 
    wifiManager.getConfiguredNetworks();
    if (configuredNetworks != null) {
        for (WifiConfiguration existingConfig : configuredNetworks) {
            if (existingConfig.SSID.equals("\"testing-tls\"")) {
                return existingConfig.networkId;
            }
        }
    }
    return -1;
}

清单权限如下：

<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.VIBRATE" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WAKE_LOCK" />

<uses-permission android:name="android.permission.OVERRIDE_WIFI_CONFIG" />
<uses-permission android:name="android.permission.NETWORK_SETTINGS" />

<uses-feature android:name="android.hardware.wifi" />
<uses-feature android:name="android.hardware.camera" />

<permission
   android:name="android.permission.INTERACT_ACROSS_USERS"
   android:protectionLevel="signature" />

错误：我总是吃UID 10189 does not have permission to update configuration error奥利奥

2018-12-28 12:23:44.571 1320-1847/? E/WifiConfigManager: UID 10189 does not have permission to update configuration "testing-tls"WPA_EAP
2018-12-28 12:23:44.571 1320-1847/? I/WifiStateMachine: connectToUserSelectNetwork Allowing uid 10189 with insufficient permissions to connect=1

调查

翻了翻源码，我addOrUpdateNetwork在WifiConfigManager类中找到了该方法的实现。

实施addOrUpdateNetwork中，标签android_8.0.0_r21（内部版本号OPD1.170816.010）如下：

• 首先检查我们是否已经有一个具有提供的网络 id 或 configKey 的网络
• 如果未找到现有网络，请验证配置并添加。
• 如果找到现有网络，请更新网络配置。在此之前，请检查应用程序是否具有更新网络所需的权限。

AddOrUpdateNetwork在内部调用一个名为 的函数canModifyNetwork：

/**
 * Checks if |uid| has permission to modify the provided configuration.
 *
 * @param config         WifiConfiguration object corresponding to the network to be modified.
 * @param uid            UID of the app requesting the modification.
 * @param ignoreLockdown Ignore the configuration lockdown checks for connection attempts.
 */
private boolean canModifyNetwork(WifiConfiguration config, int uid, boolean ignoreLockdown) {
    // Passpoint configurations are generated and managed by PasspointManager. They can be
    // added by either PasspointNetworkEvaluator (for auto connection) or Settings app
    // (for manual connection), and need to be removed once the connection is completed.
    // Since it is "owned" by us, so always allow us to modify them.
    if (config.isPasspoint() && uid == Process.WIFI_UID) {
        return true;
    }
    // EAP-SIM/AKA/AKA' network needs framework to update the anonymous identity provided
    // by authenticator back to the WifiConfiguration object.
    // Since it is "owned" by us, so always allow us to modify them.
    if (config.enterpriseConfig != null
            && uid == Process.WIFI_UID
            && TelephonyUtil.isSimEapMethod(config.enterpriseConfig.getEapMethod())) {
        return true;
    }
    final DevicePolicyManagerInternal dpmi = LocalServices.getService(
            DevicePolicyManagerInternal.class);
    final boolean isUidDeviceOwner = dpmi != null && dpmi.isActiveAdminWithPolicy(uid,
            DeviceAdminInfo.USES_POLICY_DEVICE_OWNER);
    // If |uid| corresponds to the device owner, allow all modifications.
    if (isUidDeviceOwner) {
        return true;
    }
    final boolean isCreator = (config.creatorUid == uid);
    // Check if the |uid| holds the |NETWORK_SETTINGS| permission if the caller asks us to
    // bypass the lockdown checks.
    if (ignoreLockdown) {
        return mWifiPermissionsUtil.checkNetworkSettingsPermission(uid);
    }
    // Check if device has DPM capability. If it has and |dpmi| is still null, then we
    // treat this case with suspicion and bail out.
    if (mContext.getPackageManager().hasSystemFeature(PackageManager.FEATURE_DEVICE_ADMIN)
            && dpmi == null) {
        Log.w(TAG, "Error retrieving DPMI service.");
        return false;
    }
    // WiFi config lockdown related logic. At this point we know uid is NOT a Device Owner.
    final boolean isConfigEligibleForLockdown = dpmi != null && dpmi.isActiveAdminWithPolicy(
            config.creatorUid, DeviceAdminInfo.USES_POLICY_DEVICE_OWNER);
    if (!isConfigEligibleForLockdown) {
        return isCreator || mWifiPermissionsUtil.checkNetworkSettingsPermission(uid);
    }
    final ContentResolver resolver = mContext.getContentResolver();
    final boolean isLockdownFeatureEnabled = Settings.Global.getInt(resolver,
            Settings.Global.WIFI_DEVICE_OWNER_CONFIGS_LOCKDOWN, 0) != 0;
    return !isLockdownFeatureEnabled
            && mWifiPermissionsUtil.checkNetworkSettingsPermission(uid);
}

据我所知，只有以下 uid 可以修改网络配置。

1. 系统应用
2. 设备所有者
3. 创建者（由于某种原因失败了）

我在这两款手机中得到了相同的行为。

1. 像素 2（奥利奥 8.0.0）
2. 三星 J8（奥利奥 8.0.0）

此外，三星 J8 始终显示此警告：

CertificateException: java.security.cert.CertPathValidatorException: Trust anchor for certificate path not found

题：

• 如何以编程方式更新已创建的 Wi-Fi 配置？
  • 一旦在 Wi-Fi 的内部数据库中创建了 Wi-Fi 配置，甚至可以更新它吗？
  • 在更新或启用配置之前是否必须断开 Wi-Fi？

Answer 1

挖掘源代码后，终于得到了我的问题的答案。

问题：配置创建后是否可以更新？

答：是的，Android os 允许您更新从您的应用程序创建的配置。当我调用wifiManager.addNetwork() 时，在日志窗口中打印了以下语句。

2019-01-04 12:23:16.168 1328-3114/? I/addOrUpdateNetwork:  uid = 10190 SSID "testing-tls" nid=-1
2019-01-04 12:23:16.169 1328-1851/? V/WifiConfigManager: Adding/Updating network testing-tls
2019-01-04 12:23:16.193 1328-1851/? D/WifiConfigManager: addOrUpdateNetworkInternal: added/updated config. netId=6 configKey="testing-tls"WPA_EAP uid=10190 name=in.ac.iisc.wifimonitoring vendorAP=false hiddenSSID=false autoReconnect=1
2019-01-04 12:23:16.204 1328-1851/? D/WifiConfigStore: Writing to stores completed in 7 ms.
2019-01-04 12:23:16.205 1328-1851/? D/WifiIssueDetector: report htime=2019-01-04_12:23:16 time=1546584796205 rid=105 callBy=in.ac.iisc.wifimonitoring apiName=addOrUpdateNetwork netid=6 callUid=in.ac.iisc.wifimonitoring
2019-01-04 12:23:16.206 15873-15873/in.ac.iisc.wifimonitoring I/WifiMonitorService: WifiMonitorService, #addNetwork returned: 6

问题：Oreo 中的“UID 10189 无权更新配置错误”是什么意思？

答：更新配置后，我们必须调用wifimanager.enableNetwork()方法来建立与所需接入点的连接。EnableNetwork() 的工作流程如下。

1. WifiManager.enableNetwork() 内部调用WifiStateMachine 类的SyncEnableNetwork()方法。

WifiStateMachine是跟踪 Wifi 连接状态的核心类。所有事件处理和连接状态的所有更改都在此类中启动。

2. SyncEnableNetwork() 方法将 CMD_ENABLE_NETWORK 消息发送到ConnectModeState 类。

3. 如果 disableOthers 为 true，则调用connectToUserSelectNetwork()方法并传递 networkId、调用 UID 并强制重新连接 [always false - hardcoded value] 作为参数。

4. 如果应用程序没有更新配置的所有必要权限[使用WifiConfigManager类中的checkAndUpdateLastUid()方法- 仅对系统设置/sysui 应用程序返回 true] 或者如果启用网络失败，将打印以下语句。

2018-12-28 12:23:44.571 1320-1847/? E/WifiConfigManager: UID 10189 does not have permission to update configuration "testing-tls"WPA_EAP
2018-12-28 12:23:44.571 1320-1847/? I/WifiStateMachine: connectToUserSelectNetwork Allowing uid 10189 with insufficient permissions to connect=1

注意：在 Android Pie 中，checkAndUpdateLastUid() 方法已重命名为 updateLastConnectUid()。他们也稍微修改了它的功能。

更多信息请参考下图【我不擅长画流程图。如果需要任何更改，请多多包涵或提出建议]。

问题 3：更新或启用配置之前是否必须断开 wifi 连接？

答：操作系统在以下条件下触发连接/重新连接到网络：

1. 选择的网络 ID 必须与当前连接的网络 ID 不同。
2. 如果 forceReconnect 参数为 true，Android 准备重新连接 [True only for system settings/sysui app]。

由于开发者应用程序没有强制连接的能力，我们应该断开 wifi 连接，以便在更新配置后连接/重新连接到网络。

希望这会帮助其他人。