From b9d9d7adeb5b6bdf1b95d9d3e27af38f5ae2757b Mon Sep 17 00:00:00 2001
From: Linus Tufvesson <lus@google.com>
Date: Fri, 6 May 2022 16:28:26 +0200
Subject: [PATCH] Allow some cross activity touches

Resolve app compatibility issues caused by ActivityRecordInputSink
agressivly blocking all touches. This change makes
ActivityRecordInputSink more conservable and it now only blocks touches
if the touches would otherwise:
1. Cross a task boundry
2. Go to an activity with a different uid AND that activity hasn't
   explicilty launched an activity with the same uid as this activity

Bug: 231701903
Bug: 194480991
Test: atest CtsWindowManagerDeviceTestCases:ActivityRecordInputSinkTests
Test: atest CtsWindowManagerDeviceTestCases:CrossAppDragAndDropTests
Test: atest CtsWindowManagerDeviceTestCases:PinnedStackTests
Test: atest CtsWindowManagerDeviceTestCases:WindowUntrustedTouchTest
Change-Id: Icd1668f465ba01b330c056d9ea95aed6104fc6a9
Merged-In: Icd1668f465ba01b330c056d9ea95aed6104fc6a9
---
 .../com/android/server/wm/ActivityRecord.java   |  7 ++++++-
 .../server/wm/ActivityRecordInputSink.java      | 17 +++++++++++++----
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/services/core/java/com/android/server/wm/ActivityRecord.java b/services/core/java/com/android/server/wm/ActivityRecord.java
index abbcd28575cdb..2ab1a5fd3e94f 100644
--- a/services/core/java/com/android/server/wm/ActivityRecord.java
+++ b/services/core/java/com/android/server/wm/ActivityRecord.java
@@ -926,6 +926,11 @@ final class ActivityRecord extends WindowToken implements WindowManagerService.A
 
     private final ActivityRecordInputSink mActivityRecordInputSink;
 
+    // Activities with this uid are allowed to not create an input sink while being in the same
+    // task and directly above this ActivityRecord. This field is updated whenever a new activity
+    // is launched from this ActivityRecord. Touches are always allowed within the same uid.
+    int mAllowedTouchUid;
+
     private final Runnable mPauseTimeoutRunnable = new Runnable() {
         @Override
         public void run() {
@@ -2099,7 +2104,7 @@ final class ActivityRecord extends WindowToken implements WindowManagerService.A
         }
         mAtmService.mPackageConfigPersister.updateConfigIfNeeded(this, mUserId, packageName);
 
-        mActivityRecordInputSink = new ActivityRecordInputSink(this);
+        mActivityRecordInputSink = new ActivityRecordInputSink(this, sourceRecord);
 
         updateEnterpriseThumbnailDrawable(mAtmService.mUiContext);
     }
diff --git a/services/core/java/com/android/server/wm/ActivityRecordInputSink.java b/services/core/java/com/android/server/wm/ActivityRecordInputSink.java
index 23a832496cc9c..fc22e2decbef0 100644
--- a/services/core/java/com/android/server/wm/ActivityRecordInputSink.java
+++ b/services/core/java/com/android/server/wm/ActivityRecordInputSink.java
@@ -42,14 +42,16 @@ class ActivityRecordInputSink {
 
     private InputWindowHandleWrapper mInputWindowHandleWrapper;
     private SurfaceControl mSurfaceControl;
-    private boolean mDisabled = false;
 
-    ActivityRecordInputSink(ActivityRecord activityRecord) {
+    ActivityRecordInputSink(ActivityRecord activityRecord, ActivityRecord sourceRecord) {
         mActivityRecord = activityRecord;
         mIsCompatEnabled = CompatChanges.isChangeEnabled(ENABLE_TOUCH_OPAQUE_ACTIVITIES,
                 mActivityRecord.getUid());
         mName = Integer.toHexString(System.identityHashCode(this)) + " ActivityRecordInputSink "
                 + mActivityRecord.mActivityComponent.flattenToShortString();
+        if (sourceRecord != null) {
+            sourceRecord.mAllowedTouchUid = mActivityRecord.getUid();
+        }
     }
 
     public void applyChangesToSurfaceIfChanged(SurfaceControl.Transaction transaction) {
@@ -77,8 +79,15 @@ class ActivityRecordInputSink {
         if (mInputWindowHandleWrapper == null) {
             mInputWindowHandleWrapper = new InputWindowHandleWrapper(createInputWindowHandle());
         }
-        if (mDisabled || !mIsCompatEnabled || mActivityRecord.isInTransition()) {
-            // TODO(b/208662670): Investigate if we can have feature active during animations.
+        // Don't block touches from passing through to an activity below us in the same task, if
+        // that activity is either from the same uid or if that activity has launched an activity
+        // in our uid.
+        final ActivityRecord activityBelowInTask =
+                mActivityRecord.getTask().getActivityBelow(mActivityRecord);
+        final boolean allowPassthrough = activityBelowInTask != null && (
+                activityBelowInTask.mAllowedTouchUid == mActivityRecord.getUid()
+                        || activityBelowInTask.isUid(mActivityRecord.getUid()));
+        if (allowPassthrough || !mIsCompatEnabled || mActivityRecord.isInTransition()) {
             mInputWindowHandleWrapper.setInputConfigMasked(InputConfig.NOT_TOUCHABLE,
                     InputConfig.NOT_TOUCHABLE);
         } else {