Add in-app screenshot preventing (#606)

In-app screenshot preventing fixes

client/amnezia_application.cpp

@@ -24,6 +24,7 @@
 
 #if defined(Q_OS_IOS)
     #include "platforms/ios/ios_controller.h"
+    #include <AmneziaVPN-Swift.h>
 #endif
 
 #if defined(Q_OS_ANDROID) || defined(Q_OS_IOS)
@@ -98,6 +99,10 @@ void AmneziaApplication::init()
     connect(m_settings.get(), &Settings::saveLogsChanged,
             AndroidController::instance(), &AndroidController::setSaveLogs);
 
+    AndroidController::instance()->setScreenshotsEnabled(m_settings->isScreenshotsEnabled());
+    connect(m_settings.get(), &Settings::screenshotsEnabledChanged,
+            AndroidController::instance(), &AndroidController::setScreenshotsEnabled);
+
     connect(m_settings.get(), &Settings::serverRemoved,
             AndroidController::instance(), &AndroidController::resetLastServer);
 
@@ -134,6 +139,11 @@ void AmneziaApplication::init()
         m_pageController->goToPageSettingsBackup();
         m_settingsController->importBackupFromOutside(filePath);
     });
+
+    AmneziaVPN::toggleScreenshots(m_settings->isScreenshotsEnabled());
+    connect(m_settings.get(), &Settings::screenshotsEnabledChanged, [](bool enabled) {
+        AmneziaVPN::toggleScreenshots(enabled);
+    });
 #endif
 
     m_notificationHandler.reset(NotificationHandler::create(nullptr));

client/android/src/org/amnezia/vpn/AmneziaActivity.kt

@@ -14,6 +14,7 @@ import android.os.IBinder
 import android.os.Looper
 import android.os.Message
 import android.os.Messenger
+import android.view.WindowManager.LayoutParams
 import android.webkit.MimeTypeMap
 import android.widget.Toast
 import androidx.annotation.MainThread
@@ -453,4 +454,13 @@ class AmneziaActivity : QtActivity() {
         Log.v(TAG, "Clear logs")
         Log.clearLogs()
     }
+
+    @Suppress("unused")
+    fun setScreenshotsEnabled(enabled: Boolean) {
+        Log.v(TAG, "Set screenshots enabled: $enabled")
+        mainScope.launch {
+            val flag = if (enabled) 0 else LayoutParams.FLAG_SECURE
+            window.setFlags(flag, LayoutParams.FLAG_SECURE)
+        }
+    }
 }

client/cmake/ios.cmake

@@ -107,6 +107,7 @@ target_sources(${PROJECT} PRIVATE
     ${CLIENT_ROOT_DIR}/platforms/ios/LogController.swift
     ${CLIENT_ROOT_DIR}/platforms/ios/Log.swift
     ${CLIENT_ROOT_DIR}/platforms/ios/LogRecord.swift
+    ${CLIENT_ROOT_DIR}/platforms/ios/ScreenProtection.swift
 )
 
 target_sources(${PROJECT} PRIVATE

client/platforms/android/android_controller.cpp

@@ -204,6 +204,11 @@ void AndroidController::clearLogs()
     callActivityMethod("clearLogs", "()V");
 }
 
+void AndroidController::setScreenshotsEnabled(bool enabled)
+{
+    callActivityMethod("setScreenshotsEnabled", "(Z)V", enabled);
+}
+
 // Moving log processing to the Android side
 jclass AndroidController::log;
 jmethodID AndroidController::logDebug;

client/platforms/android/android_controller.h

@@ -39,6 +39,7 @@ public:
     void setSaveLogs(bool enabled);
     void exportLogsFile(const QString &fileName);
     void clearLogs();
+    void setScreenshotsEnabled(bool enabled);
 
     static bool initLogging();
     static void messageHandler(QtMsgType type, const QMessageLogContext &context, const QString &message);

client/platforms/ios/QtAppDelegate.mm

@@ -3,7 +3,6 @@
 
 #include <QFile>
 
-UIView *_screen;
 
 @implementation QIOSApplicationDelegate (AmneziaVPNDelegate)
 
@@ -15,19 +14,6 @@ UIView *_screen;
     return YES;
 }
 
-- (void)applicationWillResignActive:(UIApplication *)application
-{
-    // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
-    // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
-    _screen = [UIScreen.mainScreen snapshotViewAfterScreenUpdates: false];
-    UIBlurEffect *blurEffect = [UIBlurEffect effectWithStyle: UIBlurEffectStyleDark];
-    UIVisualEffectView *blurBackground = [[UIVisualEffectView alloc] initWithEffect: blurEffect];
-    [_screen addSubview: blurBackground];
-    blurBackground.frame = _screen.frame;
-    UIWindow *_window = UIApplication.sharedApplication.keyWindow;
-    [_window addSubview: _screen];
-}
-
 - (void)applicationDidEnterBackground:(UIApplication *)application
 {
     // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
@@ -41,17 +27,6 @@ UIView *_screen;
     NSLog(@"In the foreground");
 }
 
-- (void)applicationDidBecomeActive:(UIApplication *)application
-{
-    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
-    [_screen removeFromSuperview];
-}
-
-- (void)applicationWillTerminate:(UIApplication *)application
-{
-    // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
-}
-
 -(void)application:(UIApplication *)application performFetchWithCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler {
     // We will add content here soon.
     NSLog(@"In the completionHandler");

client/platforms/ios/ScreenProtection.swift

@@ -0,0 +1,87 @@
+import UIKit
+
+public func toggleScreenshots(_ isEnabled: Bool) {
+  let window = UIApplication.shared.keyWindows.first!
+
+  if isEnabled {
+    ScreenProtection.shared.disable(for: window.rootViewController!.view)
+  } else {
+    ScreenProtection.shared.enable(for: window.rootViewController!.view)
+  }
+}
+
+extension UIApplication {
+  var keyWindows: [UIWindow] {
+    connectedScenes
+      .compactMap {
+        if #available(iOS 15.0, *) {
+          ($0 as? UIWindowScene)?.keyWindow
+        } else {
+          ($0 as? UIWindowScene)?.windows.first { $0.isKeyWindow }
+        }
+      }
+  }
+}
+
+class ScreenProtection {
+  public static let shared = ScreenProtection()
+
+  var pairs = [ProtectionPair]()
+
+  private var blurView: UIVisualEffectView?
+  private var recordingObservation: NSKeyValueObservation?
+
+  public func enable(for view: UIView) {
+    DispatchQueue.main.asyncAfter(deadline: .now() + 1.0) {
+      view.subviews.forEach {
+        self.pairs.append(ProtectionPair(from: $0))
+      }
+    }
+  }
+
+  public func disable(for view: UIView) {
+    DispatchQueue.main.asyncAfter(deadline: .now() + 1.0) {
+      self.pairs.forEach {
+        $0.removeProtection()
+      }
+
+      self.pairs.removeAll()
+    }
+  }
+}
+
+struct ProtectionPair {
+  let textField: UITextField
+  let layer: CALayer
+
+  init(from view: UIView) {
+    let secureTextField = UITextField()
+    secureTextField.backgroundColor = .clear
+    secureTextField.translatesAutoresizingMaskIntoConstraints = false
+    secureTextField.isSecureTextEntry = true
+
+    view.insertSubview(secureTextField, at: 0)
+    secureTextField.isUserInteractionEnabled = false
+
+    view.layer.superlayer?.addSublayer(secureTextField.layer)
+    secureTextField.layer.sublayers?.last?.addSublayer(view.layer)
+
+    secureTextField.topAnchor.constraint(equalTo: view.topAnchor, constant: 0).isActive = true
+    secureTextField.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 0).isActive = true
+    secureTextField.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 0).isActive = true
+    secureTextField.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: 0).isActive = true
+
+    self.init(textField: secureTextField, layer: view.layer)
+  }
+
+  init(textField: UITextField, layer: CALayer) {
+    self.textField = textField
+    self.layer = layer
+  }
+
+  func removeProtection() {
+    textField.superview?.superview?.layer.addSublayer(layer)
+    textField.layer.removeFromSuperlayer()
+    textField.removeFromSuperview()
+  }
+}

client/settings.h

@@ -185,12 +185,14 @@ public:
     void setScreenshotsEnabled(bool enabled)
     {
         setValue("Conf/screenshotsEnabled", enabled);
+        emit screenshotsEnabledChanged(enabled);
     }
 
     void clearSettings();
 
 signals:
     void saveLogsChanged(bool enabled);
+    void screenshotsEnabledChanged(bool enabled);
     void serverRemoved(int serverIndex);
     void settingsCleared();
 

client/ui/controllers/settingsController.cpp

@@ -7,9 +7,7 @@
 #include "ui/qautostart.h"
 #include "version.h"
 #ifdef Q_OS_ANDROID
-    #include "platforms/android/android_utils.h"
     #include "platforms/android/android_controller.h"
-    #include <QJniObject>
 #endif
 
 #ifdef Q_OS_IOS
@@ -29,20 +27,6 @@ SettingsController::SettingsController(const QSharedPointer<ServersModel> &serve
       m_settings(settings)
 {
     m_appVersion = QString("%1 (%2, %3)").arg(QString(APP_VERSION), __DATE__, GIT_COMMIT_HASH);
-
-#ifdef Q_OS_ANDROID
-    if (!m_settings->isScreenshotsEnabled()) {
-        // Set security screen for Android app
-        AndroidUtils::runOnAndroidThreadSync([]() {
-            QJniObject activity = AndroidUtils::getActivity();
-            QJniObject window = activity.callObjectMethod("getWindow", "()Landroid/view/Window;");
-            if (window.isValid()) {
-                const int FLAG_SECURE = 8192;
-                window.callMethod<void>("addFlags", "(I)V", FLAG_SECURE);
-            }
-        });
-    }
-#endif
 }
 
 void SettingsController::toggleAmneziaDns(bool enable)
@@ -204,19 +188,6 @@ bool SettingsController::isScreenshotsEnabled()
 void SettingsController::toggleScreenshotsEnabled(bool enable)
 {
     m_settings->setScreenshotsEnabled(enable);
-#ifdef Q_OS_ANDROID
-    std::string command = enable ? "clearFlags" : "addFlags";
-
-    // Set security screen for Android app
-    AndroidUtils::runOnAndroidThreadSync([&command]() {
-        QJniObject activity = AndroidUtils::getActivity();
-        QJniObject window = activity.callObjectMethod("getWindow", "()Landroid/view/Window;");
-        if (window.isValid()) {
-            const int FLAG_SECURE = 8192;
-            window.callMethod<void>(command.c_str(), "(I)V", FLAG_SECURE);
-        }
-    });
-#endif
 }
 
 bool SettingsController::isCameraPresent()

client/ui/qml/Pages2/PageHome.qml

@@ -160,7 +160,6 @@ PageType {
                 Layout.alignment: Qt.AlignHCenter | Qt.AlignVCenter
                 text: ServersModel.defaultServerDescriptionCollapsed
             }
-
         }
         expandedContent: Item {
             id: serverMenuContainer