From 17df433a3d96fb6c00dc7078fd0f8048645ace6a Mon Sep 17 00:00:00 2001
From: Louis Chang <louischang@google.com>
Date: Wed, 28 Sep 2022 06:46:29 +0000
Subject: [RESTRICT AUTOMERGE] Trim the activity info of another uid if no
 privilege

The activity info could be from another uid which is different
from the app that hosts the task. The information should be
trimmed if the caller app doesn't have the privilege.

Bug: 243130512
Test: verified locally
Test: atest RecentTasksTest
Change-Id: Ia343ac70e5bb9aeae718fca6674e1ca491a14512
(cherry picked from commit 401e782b244bf84fd5aab371f60c2e52d6226fb3)
---
 .../java/com/android/server/wm/AppTaskImpl.java     |  2 +-
 .../java/com/android/server/wm/RecentTasks.java     |  8 ++++++--
 .../java/com/android/server/wm/RunningTasks.java    |  4 ++++
 services/core/java/com/android/server/wm/Task.java  | 21 +++++++++++++++++++++
 4 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/services/core/java/com/android/server/wm/AppTaskImpl.java b/services/core/java/com/android/server/wm/AppTaskImpl.java
index dd1d55b2d54d..2fd5963d653b 100644
--- a/services/core/java/com/android/server/wm/AppTaskImpl.java
+++ b/services/core/java/com/android/server/wm/AppTaskImpl.java
@@ -84,7 +84,7 @@ class AppTaskImpl extends IAppTask.Stub {
                     throw new IllegalArgumentException("Unable to find task ID " + mTaskId);
                 }
                 return mService.getRecentTasks().createRecentTaskInfo(task,
-                        false /* stripExtras */);
+                        false /* stripExtras */, true /* getTasksAllowed */);
             } finally {
                 Binder.restoreCallingIdentity(origId);
             }
diff --git a/services/core/java/com/android/server/wm/RecentTasks.java b/services/core/java/com/android/server/wm/RecentTasks.java
index 851b533a550d..3a963e750b1c 100644
--- a/services/core/java/com/android/server/wm/RecentTasks.java
+++ b/services/core/java/com/android/server/wm/RecentTasks.java
@@ -961,7 +961,7 @@ class RecentTasks {
                 continue;
             }
 
-            res.add(createRecentTaskInfo(task, true /* stripExtras */));
+            res.add(createRecentTaskInfo(task, true /* stripExtras */, getTasksAllowed));
         }
         return res;
     }
@@ -1833,12 +1833,16 @@ class RecentTasks {
     /**
      * Creates a new RecentTaskInfo from a Task.
      */
-    ActivityManager.RecentTaskInfo createRecentTaskInfo(Task tr, boolean stripExtras) {
+    ActivityManager.RecentTaskInfo createRecentTaskInfo(Task tr, boolean stripExtras,
+            boolean getTasksAllowed) {
         ActivityManager.RecentTaskInfo rti = new ActivityManager.RecentTaskInfo();
         tr.fillTaskInfo(rti, stripExtras);
         // Fill in some deprecated values
         rti.id = rti.isRunning ? rti.taskId : INVALID_TASK_ID;
         rti.persistentId = rti.taskId;
+        if (!getTasksAllowed) {
+            Task.trimIneffectiveInfo(tr, rti);
+        }
         return rti;
     }
 
diff --git a/services/core/java/com/android/server/wm/RunningTasks.java b/services/core/java/com/android/server/wm/RunningTasks.java
index 3509ba72d058..3c7917bb05d1 100644
--- a/services/core/java/com/android/server/wm/RunningTasks.java
+++ b/services/core/java/com/android/server/wm/RunningTasks.java
@@ -129,6 +129,10 @@ class RunningTasks {
         final RunningTaskInfo rti = task.getTaskInfo();
         // Fill in some deprecated values
         rti.id = rti.taskId;
+
+        if (!mAllowed) {
+            Task.trimIneffectiveInfo(task, rti);
+        }
         return rti;
     }
 }
diff --git a/services/core/java/com/android/server/wm/Task.java b/services/core/java/com/android/server/wm/Task.java
index 4b4e936c73c1..d4c4c76c9b62 100644
--- a/services/core/java/com/android/server/wm/Task.java
+++ b/services/core/java/com/android/server/wm/Task.java
@@ -3631,6 +3631,27 @@ class Task extends WindowContainer<WindowContainer> {
                 : null;
     }
 
+    /**
+     * Removes the activity info if the activity belongs to a different uid, which is
+     * different from the app that hosts the task.
+     */
+    static void trimIneffectiveInfo(Task task, TaskInfo info) {
+        final ActivityRecord baseActivity = task.getActivity(r -> !r.finishing,
+                false /* traverseTopToBottom */);
+        final int baseActivityUid =
+                baseActivity != null ? baseActivity.getUid() : task.effectiveUid;
+
+        if (info.topActivityInfo != null
+                && task.effectiveUid != info.topActivityInfo.applicationInfo.uid) {
+            info.topActivity = null;
+            info.topActivityInfo = null;
+        }
+
+        if (task.effectiveUid != baseActivityUid) {
+            info.baseActivity = null;
+        }
+    }
+
     /**
      * Returns a {@link TaskInfo} with information from this task.
      */
-- 
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