From 0a4f661ec6a18a0ddc47b6d9280a10b8d16c9457 Mon Sep 17 00:00:00 2001
From: Jeff Chang <chengjeff@google.com>
Date: Tue, 25 Jan 2022 10:37:29 +0800
Subject: [PATCH] [RESTRICT AUTOMERGE] Do not resume activity if behind a
 translucent task

The top-focusable activity resides in the RESUMED state while the app
process is newly created and attached. The behavior may enable UI
hijacking attacks against apps implementing authentication.

This CL disallows the system to resume the activity for the case if it
is not visible or is occluded by other translucent tasks.

Bug: 211481342
Test: atest CtsWindowManagerDeviceTestCases:ActivityLifecycleTests
Change-Id: I7903494cf928b5b5613700262b7c5fff10f3c5a0
---
 .../com/android/server/wm/EnsureActivitiesVisibleHelper.java   | 2 +-
 .../core/java/com/android/server/wm/RootWindowContainer.java   | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/services/core/java/com/android/server/wm/EnsureActivitiesVisibleHelper.java b/services/core/java/com/android/server/wm/EnsureActivitiesVisibleHelper.java
index badb1f5a0a12d..4708d00269310 100644
--- a/services/core/java/com/android/server/wm/EnsureActivitiesVisibleHelper.java
+++ b/services/core/java/com/android/server/wm/EnsureActivitiesVisibleHelper.java
@@ -97,7 +97,7 @@ class EnsureActivitiesVisibleHelper {
         // activities are actually behind other fullscreen activities, but still required
         // to be visible (such as performing Recents animation).
         final boolean resumeTopActivity = mTop != null && !mTop.mLaunchTaskBehind
-                && mTaskFragment.isTopActivityFocusable()
+                && mTaskFragment.canBeResumed(starting)
                 && (starting == null || !starting.isDescendantOf(mTaskFragment));
 
         ArrayList<TaskFragment> adjacentTaskFragments = null;
diff --git a/services/core/java/com/android/server/wm/RootWindowContainer.java b/services/core/java/com/android/server/wm/RootWindowContainer.java
index fbc8f73b53b00..628e124877e9b 100644
--- a/services/core/java/com/android/server/wm/RootWindowContainer.java
+++ b/services/core/java/com/android/server/wm/RootWindowContainer.java
@@ -1979,7 +1979,8 @@ class RootWindowContainer extends WindowContainer<DisplayContent>
 
         try {
             if (mTaskSupervisor.realStartActivityLocked(r, app,
-                    top == r && r.isFocusable() /*andResume*/, true /*checkConfig*/)) {
+                    top == r && r.getTask().canBeResumed(r) /*andResume*/,
+                    true /*checkConfig*/)) {
                 mTmpBoolean = true;
             }
         } catch (RemoteException e) {