Block screen recording during registration by applying FLAG_SECURE.

Co-authored-by: Greyson Parrelli <greyson@signal.org>

app/src/main/java/org/thoughtcrime/securesms/backup/v2/ui/subscription/EnterKeyScreen.kt

@@ -43,6 +43,7 @@ import org.signal.core.models.AccountEntropyPool
 import org.signal.core.ui.compose.Buttons
 import org.signal.core.ui.compose.horizontalGutters
 import org.thoughtcrime.securesms.R
+import org.thoughtcrime.securesms.components.TemporaryScreenshotSecurity
 import org.thoughtcrime.securesms.fonts.MonoTypeface
 import org.thoughtcrime.securesms.registration.ui.restore.BackupKeyVisualTransformation
 import org.thoughtcrime.securesms.registration.ui.restore.attachBackupKeyAutoFillHelper
@@ -59,6 +60,8 @@ fun EnterKeyScreen(
   captionContent: @Composable () -> Unit,
   seeKeyButton: @Composable () -> Unit
 ) {
+  TemporaryScreenshotSecurity.bind()
+
   Column(
     verticalArrangement = Arrangement.SpaceBetween,
     modifier = Modifier

app/src/main/java/org/thoughtcrime/securesms/backup/v2/ui/subscription/MessageBackupsKeyRecordScreen.kt

@@ -59,6 +59,7 @@ import org.signal.core.ui.compose.horizontalGutters
 import org.signal.core.ui.compose.theme.SignalTheme
 import org.signal.core.util.Util
 import org.thoughtcrime.securesms.R
+import org.thoughtcrime.securesms.components.TemporaryScreenshotSecurity
 import org.thoughtcrime.securesms.components.settings.app.backups.remote.BackupKeyCredentialManagerHandler
 import org.thoughtcrime.securesms.components.settings.app.backups.remote.BackupKeySaveState
 import org.thoughtcrime.securesms.fonts.MonoTypeface
@@ -133,6 +134,8 @@ fun MessageBackupsKeyRecordScreen(
   mode: MessageBackupsKeyRecordMode = MessageBackupsKeyRecordMode.Next(onNextClick = {}),
   notifyKeyIsSameAsOnDeviceBackupKey: Boolean = false
 ) {
+  TemporaryScreenshotSecurity.bind()
+
   val snackbarHostState = remember { SnackbarHostState() }
   val backupKeyString = remember(backupKey) {
     backupKey.chunked(4).joinToString("  ")

app/src/main/java/org/thoughtcrime/securesms/components/TemporaryScreenshotSecurity.kt

@@ -5,18 +5,41 @@
 
 package org.thoughtcrime.securesms.components
 
+import android.view.Window
 import android.view.WindowManager
 import androidx.activity.ComponentActivity
+import androidx.activity.compose.LocalActivity
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
 import androidx.fragment.app.Fragment
 import androidx.lifecycle.DefaultLifecycleObserver
 import androidx.lifecycle.LifecycleOwner
 import org.thoughtcrime.securesms.util.TextSecurePreferences
+import java.util.WeakHashMap
 
 /**
  * Applies temporary screenshot security for the given component lifecycle.
+ *
+ * Multiple callers can request security on the same window concurrently; the
+ * flag is only cleared once every caller has released its hold.
  */
 object TemporaryScreenshotSecurity {
 
+  private val activeHolds = WeakHashMap<Window, Int>()
+
+  @Composable
+  fun bind() {
+    val activity = LocalActivity.current as? ComponentActivity ?: return
+
+    DisposableEffect(activity) {
+      acquire(activity)
+
+      onDispose {
+        release(activity)
+      }
+    }
+  }
+
   @JvmStatic
   fun bindToViewLifecycleOwner(fragment: Fragment) {
     val observer = LifecycleObserver { fragment.requireActivity() }
@@ -31,21 +54,37 @@ object TemporaryScreenshotSecurity {
     activity.lifecycle.addObserver(observer)
   }
 
+  private fun acquire(activity: ComponentActivity) {
+    val window = activity.window
+    val previous = activeHolds[window] ?: 0
+    activeHolds[window] = previous + 1
+    if (previous == 0 && !TextSecurePreferences.isScreenSecurityEnabled(activity)) {
+      window.addFlags(WindowManager.LayoutParams.FLAG_SECURE)
+    }
+  }
+
+  private fun release(activity: ComponentActivity) {
+    val window = activity.window
+    val next = ((activeHolds[window] ?: 0) - 1).coerceAtLeast(0)
+    if (next == 0) {
+      activeHolds.remove(window)
+      if (!TextSecurePreferences.isScreenSecurityEnabled(activity)) {
+        window.clearFlags(WindowManager.LayoutParams.FLAG_SECURE)
+      }
+    } else {
+      activeHolds[window] = next
+    }
+  }
+
   private class LifecycleObserver(
     private val activityProvider: () -> ComponentActivity
   ) : DefaultLifecycleObserver {
     override fun onResume(owner: LifecycleOwner) {
-      val activity = activityProvider()
-      if (!TextSecurePreferences.isScreenSecurityEnabled(activity)) {
-        activity.window.addFlags(WindowManager.LayoutParams.FLAG_SECURE)
-      }
+      acquire(activityProvider())
     }
 
     override fun onPause(owner: LifecycleOwner) {
-      val activity = activityProvider()
-      if (!TextSecurePreferences.isScreenSecurityEnabled(activity)) {
-        activity.window.clearFlags(WindowManager.LayoutParams.FLAG_SECURE)
-      }
+      release(activityProvider())
     }
   }
 }

app/src/main/java/org/thoughtcrime/securesms/registration/ui/RegistrationActivity.kt

@@ -12,7 +12,6 @@ import androidx.activity.viewModels
 import androidx.lifecycle.DefaultLifecycleObserver
 import androidx.lifecycle.LifecycleOwner
 import androidx.navigation.ActivityNavigator
-import org.signal.core.util.logging.Log
 import org.thoughtcrime.securesms.BaseActivity
 import org.thoughtcrime.securesms.MainActivity
 import org.thoughtcrime.securesms.R
@@ -26,8 +25,6 @@ import org.thoughtcrime.securesms.util.DynamicNoActionBarTheme
  */
 class RegistrationActivity : BaseActivity() {
 
-  private val TAG = Log.tag(RegistrationActivity::class.java)
-
   private val dynamicTheme = DynamicNoActionBarTheme()
   val sharedViewModel: RegistrationViewModel by viewModels()
 

app/src/main/java/org/thoughtcrime/securesms/registration/ui/restore/EnterBackupKeyScreen.kt

@@ -57,6 +57,7 @@ import org.signal.core.ui.compose.Previews
 import org.signal.core.ui.compose.horizontalGutters
 import org.thoughtcrime.securesms.R
 import org.thoughtcrime.securesms.backup.v2.ui.BackupsIconColors
+import org.thoughtcrime.securesms.components.TemporaryScreenshotSecurity
 import org.thoughtcrime.securesms.fonts.MonoTypeface
 import org.thoughtcrime.securesms.registration.ui.shared.RegistrationScreen
 
@@ -78,6 +79,8 @@ fun EnterBackupKeyScreen(
   onSkip: () -> Unit = {},
   dialogContent: @Composable () -> Unit
 ) {
+  TemporaryScreenshotSecurity.bind()
+
   val coroutineScope = rememberCoroutineScope()
   val sheetState = rememberModalBottomSheetState(
     skipPartiallyExpanded = true

app/src/main/java/org/thoughtcrime/securesms/registration/ui/restore/local/EnterLocalBackupKeyScreen.kt

@@ -36,6 +36,7 @@ import org.signal.core.ui.compose.CircularProgressWrapper
 import org.signal.core.ui.compose.DayNightPreviews
 import org.signal.core.ui.compose.Previews
 import org.thoughtcrime.securesms.R
+import org.thoughtcrime.securesms.components.TemporaryScreenshotSecurity
 import org.thoughtcrime.securesms.fonts.MonoTypeface
 import org.thoughtcrime.securesms.registration.data.network.RegisterAccountResult
 import org.thoughtcrime.securesms.registration.ui.restore.AccountEntropyPoolVerification
@@ -59,6 +60,8 @@ fun EnterLocalBackupKeyScreen(
   onRegistrationErrorDismiss: () -> Unit = {},
   onBackupKeyHelp: () -> Unit = {}
 ) {
+  TemporaryScreenshotSecurity.bind()
+
   val visualTransform = remember { BackupKeyVisualTransformation(chunkSize = 4) }
   val keyboardController = LocalSoftwareKeyboardController.current
   val focusRequester = remember { FocusRequester() }