From 60a6583adfdb50df1643e0df2dc37096f977a483 Mon Sep 17 00:00:00 2001
From: Linus Tufvesson <lus@google.com>
Date: Tue, 4 Feb 2020 16:41:06 +0000
Subject: [PATCH] RESTRICT AUTOMERGE Block TYPE_PRESENTATION windows on default
 display

... and any other display that isn't considered a public presentation
display, as per Display.isPublicPresentation()

Bug: 141745510
Test: cts-tradefed run cts -m CtsWindowManagerDeviceTestCases -t android.server.wm.PresentationTest
Change-Id: I2aaab1903dee54190338f7b6e49888aa51437108
---
 core/java/android/app/Presentation.java          | 16 +++++++++-------
 .../android/server/wm/WindowManagerService.java  |  8 ++++++++
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/core/java/android/app/Presentation.java b/core/java/android/app/Presentation.java
index cb72d4d5dc2cf..b3a39f5025c7e 100644
--- a/core/java/android/app/Presentation.java
+++ b/core/java/android/app/Presentation.java
@@ -26,18 +26,18 @@ import android.content.res.Resources;
 import android.hardware.display.DisplayManager;
 import android.hardware.display.DisplayManager.DisplayListener;
 import android.os.Binder;
+import android.os.Handler;
 import android.os.IBinder;
+import android.os.Message;
+import android.util.DisplayMetrics;
+import android.util.Log;
+import android.util.TypedValue;
 import android.view.ContextThemeWrapper;
 import android.view.Display;
 import android.view.Gravity;
 import android.view.Window;
 import android.view.WindowManager;
 import android.view.WindowManagerImpl;
-import android.os.Handler;
-import android.os.Message;
-import android.util.DisplayMetrics;
-import android.util.Log;
-import android.util.TypedValue;
 
 /**
  * Base class for presentations.
@@ -116,7 +116,9 @@ import android.util.TypedValue;
  * The display manager keeps track of all displays in the system.  However, not all
  * displays are appropriate for showing presentations.  For example, if an activity
  * attempted to show a presentation on the main display it might obscure its own content
- * (it's like opening a dialog on top of your activity).
+ * (it's like opening a dialog on top of your activity).  Creating a presentation on the main
+ * display will result in {@link android.view.WindowManager.InvalidDisplayException} being thrown
+ * when invoking {@link #show()}.
  * </p><p>
  * Here's how to identify suitable displays for showing presentations using
  * {@link DisplayManager#getDisplays(String)} and the
@@ -243,7 +245,7 @@ public class Presentation extends Dialog {
     /**
      * Inherited from {@link Dialog#show}. Will throw
      * {@link android.view.WindowManager.InvalidDisplayException} if the specified secondary
-     * {@link Display} can't be found.
+     * {@link Display} can't be found or if it does not have {@link Display#FLAG_PRESENTATION} set.
      */
     @Override
     public void show() {
diff --git a/services/core/java/com/android/server/wm/WindowManagerService.java b/services/core/java/com/android/server/wm/WindowManagerService.java
index 436a5c729b86d..2de8ae155f817 100644
--- a/services/core/java/com/android/server/wm/WindowManagerService.java
+++ b/services/core/java/com/android/server/wm/WindowManagerService.java
@@ -60,6 +60,7 @@ import static android.view.WindowManager.LayoutParams.TYPE_DREAM;
 import static android.view.WindowManager.LayoutParams.TYPE_INPUT_METHOD;
 import static android.view.WindowManager.LayoutParams.TYPE_INPUT_METHOD_DIALOG;
 import static android.view.WindowManager.LayoutParams.TYPE_NAVIGATION_BAR;
+import static android.view.WindowManager.LayoutParams.TYPE_PRESENTATION;
 import static android.view.WindowManager.LayoutParams.TYPE_PRIVATE_PRESENTATION;
 import static android.view.WindowManager.LayoutParams.TYPE_QS_DIALOG;
 import static android.view.WindowManager.LayoutParams.TYPE_STATUS_BAR;
@@ -1276,6 +1277,13 @@ public class WindowManagerService extends IWindowManager.Stub
                 return WindowManagerGlobal.ADD_PERMISSION_DENIED;
             }
 
+            if (type == TYPE_PRESENTATION && !displayContent.getDisplay().isPublicPresentation()) {
+                Slog.w(TAG_WM,
+                        "Attempted to add presentation window to a non-suitable display.  "
+                                + "Aborting.");
+                return WindowManagerGlobal.ADD_INVALID_DISPLAY;
+            }
+
             AppWindowToken atoken = null;
             final boolean hasParent = parentWindow != null;
             // Use existing parent window token for child windows since they go in the same token