From b7ac0ad3c76c16f95289176bbb6bbd608bfb7573 Mon Sep 17 00:00:00 2001
From: Jan Tomljanovic <jtomljanovic@google.com>
Date: Fri, 12 Mar 2021 16:17:21 +0000
Subject: [PATCH] Add permission for avoiding toast rate limiting.

I've decided to use a new permission since it needs to be added to
the settings app, which doesn't have INTERNAL_SYSTEM_WINDOW permission,
so I didn't want to add it as it may enable it to do some other things
it's not supposed to do.

Bug: 182448615
Test: atest android.widget.cts.ToastTest as regression test
Test: atest NotificationManagerServiceTest
Change-Id: I6adc84856f1fe9c33e0ad8470e7248a20587a1e9
---
 core/res/AndroidManifest.xml                  |  8 +++
 packages/Shell/AndroidManifest.xml            |  3 +
 .../NotificationManagerService.java           | 18 ++++-
 .../NotificationManagerServiceTest.java       | 70 ++++++++++++++++++-
 4 files changed, 95 insertions(+), 4 deletions(-)

diff --git a/core/res/AndroidManifest.xml b/core/res/AndroidManifest.xml
index 29d5e7bbfcd13..692a3d25b0431 100644
--- a/core/res/AndroidManifest.xml
+++ b/core/res/AndroidManifest.xml
@@ -3447,6 +3447,14 @@
     <permission android:name="android.permission.INTERNAL_SYSTEM_WINDOW"
         android:protectionLevel="signature" />
 
+    <!-- Allows an application to avoid all toast rate limiting restrictions.
+         <p>Not for use by third-party applications.
+         @hide
+    -->
+    <permission android:name="android.permission.UNLIMITED_TOASTS"
+                android:protectionLevel="signature" />
+    <uses-permission android:name="android.permission.UNLIMITED_TOASTS" />
+
     <!-- @SystemApi Allows an application to use
          {@link android.view.WindowManager.LayoutsParams#SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS}
          to hide non-system-overlay windows.
diff --git a/packages/Shell/AndroidManifest.xml b/packages/Shell/AndroidManifest.xml
index b86ae6d199d72..c7627f273babc 100644
--- a/packages/Shell/AndroidManifest.xml
+++ b/packages/Shell/AndroidManifest.xml
@@ -438,6 +438,9 @@
     <!-- Permission required for CTS test - ResourceObserverNativeTest -->
     <uses-permission android:name="android.permission.REGISTER_MEDIA_RESOURCE_OBSERVER" />
 
+    <!-- Permission required for CTS test - android.widget.cts.ToastTest -->
+    <uses-permission android:name="android.permission.UNLIMITED_TOASTS" />
+
     <application android:label="@string/app_label"
                 android:theme="@android:style/Theme.DeviceDefault.DayNight"
                 android:defaultToDeviceProtectedStorage="true"
diff --git a/services/core/java/com/android/server/notification/NotificationManagerService.java b/services/core/java/com/android/server/notification/NotificationManagerService.java
index 68fc14c131439..08dbd77708a4a 100755
--- a/services/core/java/com/android/server/notification/NotificationManagerService.java
+++ b/services/core/java/com/android/server/notification/NotificationManagerService.java
@@ -7490,9 +7490,11 @@ public class NotificationManagerService extends SystemService {
             boolean rateLimitingEnabled =
                     !mToastRateLimitingDisabledUids.contains(record.uid);
             boolean isWithinQuota =
-                    mToastRateLimiter.isWithinQuota(userId, record.pkg, TOAST_QUOTA_TAG);
+                    mToastRateLimiter.isWithinQuota(userId, record.pkg, TOAST_QUOTA_TAG)
+                            || isExemptFromRateLimiting(record.pkg, userId);
 
-            if (tryShowToast(record, rateLimitingEnabled, isWithinQuota)) {
+            if (tryShowToast(
+                    record, rateLimitingEnabled, isWithinQuota)) {
                 scheduleDurationReachedLocked(record, lastToastWasTextRecord);
                 mIsCurrentToastShown = true;
                 if (rateLimitingEnabled) {
@@ -7526,6 +7528,18 @@ public class NotificationManagerService extends SystemService {
         return record.show();
     }
 
+    private boolean isExemptFromRateLimiting(String pkg, int userId) {
+        boolean isExemptFromRateLimiting = false;
+        try {
+            isExemptFromRateLimiting = mPackageManager.checkPermission(
+                    android.Manifest.permission.UNLIMITED_TOASTS, pkg, userId)
+                    == PackageManager.PERMISSION_GRANTED;
+        } catch (RemoteException e) {
+            Slog.e(TAG, "Failed to connect with package manager");
+        }
+        return isExemptFromRateLimiting;
+    }
+
     /** Reports rate limiting toasts compat change (used when the toast was blocked). */
     private void reportCompatRateLimitingToastsChange(int uid) {
         final long id = Binder.clearCallingIdentity();
diff --git a/services/tests/uiservicestests/src/com/android/server/notification/NotificationManagerServiceTest.java b/services/tests/uiservicestests/src/com/android/server/notification/NotificationManagerServiceTest.java
index e37b82fe7ac07..aa9feeaaf9590 100755
--- a/services/tests/uiservicestests/src/com/android/server/notification/NotificationManagerServiceTest.java
+++ b/services/tests/uiservicestests/src/com/android/server/notification/NotificationManagerServiceTest.java
@@ -4910,6 +4910,7 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
         assertEquals(0, mService.mToastQueue.size());
         mService.isSystemUid = false;
         setToastRateIsWithinQuota(true);
+        setIfPackageHasPermissionToAvoidToastRateLimiting(testPackage, false);
 
         // package is not suspended
         when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
@@ -4933,6 +4934,7 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
         assertEquals(0, mService.mToastQueue.size());
         mService.isSystemUid = false;
         setToastRateIsWithinQuota(true);
+        setIfPackageHasPermissionToAvoidToastRateLimiting(testPackage, false);
 
         // package is not suspended
         when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
@@ -4952,6 +4954,7 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
         assertEquals(0, mService.mToastQueue.size());
         mService.isSystemUid = false;
         setToastRateIsWithinQuota(true);
+        setIfPackageHasPermissionToAvoidToastRateLimiting(testPackage, false);
 
         // package is not suspended
         when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
@@ -4974,11 +4977,12 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
     }
 
     @Test
-    public void testToastRateLimiterCanPreventsShowCallForCustomToast() throws Exception {
+    public void testToastRateLimiterCanPreventShowCallForCustomToast() throws Exception {
         final String testPackage = "testPackageName";
         assertEquals(0, mService.mToastQueue.size());
         mService.isSystemUid = false;
         setToastRateIsWithinQuota(false); // rate limit reached
+        setIfPackageHasPermissionToAvoidToastRateLimiting(testPackage, false);
 
         // package is not suspended
         when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
@@ -4994,6 +4998,29 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
         verify(callback, times(0)).show(any());
     }
 
+    @Test
+    public void testCustomToastRateLimiterAllowsLimitAvoidanceWithPermission() throws Exception {
+        final String testPackage = "testPackageName";
+        assertEquals(0, mService.mToastQueue.size());
+        mService.isSystemUid = false;
+        setToastRateIsWithinQuota(false); // rate limit reached
+        // Avoids rate limiting.
+        setIfPackageHasPermissionToAvoidToastRateLimiting(testPackage, true);
+
+        // package is not suspended
+        when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
+                .thenReturn(false);
+
+        setAppInForegroundForToasts(mUid, true);
+
+        Binder token = new Binder();
+        ITransientNotification callback = mock(ITransientNotification.class);
+        INotificationManager nmService = (INotificationManager) mService.mService;
+
+        nmService.enqueueToast(testPackage, token, callback, 2000, 0);
+        verify(callback).show(any());
+    }
+
     @Test
     public void testCustomToastPostedWhileInForeground_blockedIfAppGoesToBackground()
             throws Exception {
@@ -5001,6 +5028,7 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
         assertEquals(0, mService.mToastQueue.size());
         mService.isSystemUid = false;
         setToastRateIsWithinQuota(true);
+        setIfPackageHasPermissionToAvoidToastRateLimiting(testPackage, false);
 
         // package is not suspended
         when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
@@ -5034,6 +5062,7 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
         assertEquals(0, mService.mToastQueue.size());
         mService.isSystemUid = false;
         setToastRateIsWithinQuota(true);
+        setIfPackageHasPermissionToAvoidToastRateLimiting(testPackage, false);
 
         // package is not suspended
         when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
@@ -5053,6 +5082,7 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
         assertEquals(0, mService.mToastQueue.size());
         mService.isSystemUid = false;
         setToastRateIsWithinQuota(true);
+        setIfPackageHasPermissionToAvoidToastRateLimiting(testPackage, false);
 
         // package is not suspended
         when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
@@ -5072,6 +5102,7 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
         assertEquals(0, mService.mToastQueue.size());
         mService.isSystemUid = false;
         setToastRateIsWithinQuota(true);
+        setIfPackageHasPermissionToAvoidToastRateLimiting(testPackage, false);
 
         // package is not suspended
         when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
@@ -5095,11 +5126,12 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
     }
 
     @Test
-    public void testToastRateLimiterCanPreventsShowCallForTextToast() throws Exception {
+    public void testToastRateLimiterCanPreventShowCallForTextToast() throws Exception {
         final String testPackage = "testPackageName";
         assertEquals(0, mService.mToastQueue.size());
         mService.isSystemUid = false;
         setToastRateIsWithinQuota(false); // rate limit reached
+        setIfPackageHasPermissionToAvoidToastRateLimiting(testPackage, false);
 
         // package is not suspended
         when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
@@ -5113,6 +5145,25 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
                 .showToast(anyInt(), any(), any(), any(), any(), anyInt(), any());
     }
 
+    @Test
+    public void testTextToastRateLimiterAllowsLimitAvoidanceWithPermission() throws Exception {
+        final String testPackage = "testPackageName";
+        assertEquals(0, mService.mToastQueue.size());
+        mService.isSystemUid = false;
+        setToastRateIsWithinQuota(false); // rate limit reached
+        setIfPackageHasPermissionToAvoidToastRateLimiting(testPackage, true);
+
+        // package is not suspended
+        when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
+                .thenReturn(false);
+
+        Binder token = new Binder();
+        INotificationManager nmService = (INotificationManager) mService.mService;
+
+        nmService.enqueueTextToast(testPackage, token, "Text", 2000, 0, null);
+        verify(mStatusBar).showToast(anyInt(), any(), any(), any(), any(), anyInt(), any());
+    }
+
     @Test
     public void backgroundSystemCustomToast_callsSetProcessImportantAsForegroundForToast() throws
             Exception {
@@ -5120,6 +5171,7 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
         assertEquals(0, mService.mToastQueue.size());
         mService.isSystemUid = true;
         setToastRateIsWithinQuota(true);
+        setIfPackageHasPermissionToAvoidToastRateLimiting(testPackage, false);
 
         // package is not suspended
         when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
@@ -5145,6 +5197,7 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
         assertEquals(0, mService.mToastQueue.size());
         mService.isSystemUid = false;
         setToastRateIsWithinQuota(true);
+        setIfPackageHasPermissionToAvoidToastRateLimiting(testPackage, false);
 
         // package is not suspended
         when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
@@ -5166,6 +5219,7 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
         assertEquals(0, mService.mToastQueue.size());
         mService.isSystemUid = false;
         setToastRateIsWithinQuota(true);
+        setIfPackageHasPermissionToAvoidToastRateLimiting(testPackage, false);
 
         // package is not suspended
         when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
@@ -5186,6 +5240,7 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
         assertEquals(0, mService.mToastQueue.size());
         mService.isSystemUid = false;
         setToastRateIsWithinQuota(true);
+        setIfPackageHasPermissionToAvoidToastRateLimiting(testPackage, false);
 
         // package is not suspended
         when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
@@ -5203,6 +5258,7 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
         assertEquals(0, mService.mToastQueue.size());
         mService.isSystemUid = false;
         setToastRateIsWithinQuota(true);
+        setIfPackageHasPermissionToAvoidToastRateLimiting(testPackage, false);
 
         // package is suspended
         when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
@@ -5224,6 +5280,7 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
         assertEquals(0, mService.mToastQueue.size());
         mService.isSystemUid = false;
         setToastRateIsWithinQuota(true);
+        setIfPackageHasPermissionToAvoidToastRateLimiting(testPackage, false);
 
         // package is not suspended
         when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
@@ -5247,6 +5304,7 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
         assertEquals(0, mService.mToastQueue.size());
         mService.isSystemUid = true;
         setToastRateIsWithinQuota(true);
+        setIfPackageHasPermissionToAvoidToastRateLimiting(testPackage, false);
 
         // package is suspended
         when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
@@ -5270,6 +5328,7 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
         assertEquals(0, mService.mToastQueue.size());
         mService.isSystemUid = false;
         setToastRateIsWithinQuota(true);
+        setIfPackageHasPermissionToAvoidToastRateLimiting(testPackage, false);
 
         // package is not suspended
         when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
@@ -5305,6 +5364,13 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
                 .thenReturn(isWithinQuota);
     }
 
+    private void setIfPackageHasPermissionToAvoidToastRateLimiting(
+            String pkg, boolean hasPermission) throws Exception {
+        when(mPackageManager.checkPermission(android.Manifest.permission.UNLIMITED_TOASTS,
+                pkg, UserHandle.getUserId(mUid)))
+                .thenReturn(hasPermission ? PERMISSION_GRANTED : PERMISSION_DENIED);
+    }
+
     @Test
     public void testOnPanelRevealedAndHidden() {
         int items = 5;