From 48cf98cb917217b899dfc4dec43b8f6d40924038 Mon Sep 17 00:00:00 2001
From: Sandro Meier <sandromeier@google.com>
Date: Thu, 17 Nov 2022 15:30:45 +0000
Subject: [PATCH] Enforce VirtualTouchscreen dimensions are positive

Adds an IllegalArgumentException to the implementation of
createVirtualTouchscreen if the dimension has one or two non positive
components. Without this check the native layer silently fails (only a
warning is printed in the logs). The creation of the VirtualTouchscreen
looks successful because the DeviceCretionException does not get passed
past the Binder call. When the first VirtualTouchEvent is sent to the
VirtualTouchscreen the sendTouchEvent() method throws an exception
because it can't find the underlying input device descriptor.

Bug: 259554911
Test: atest FrameworksServicesTests:VirtualDeviceManagerServiceTest
Change-Id: I085b8822d0f364b49060404480795626554fc155
---
 .../companion/virtual/VirtualDeviceImpl.java  |  7 +++++
 .../VirtualDeviceManagerServiceTest.java      | 29 +++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/services/companion/java/com/android/server/companion/virtual/VirtualDeviceImpl.java b/services/companion/java/com/android/server/companion/virtual/VirtualDeviceImpl.java
index be2107529f8b4..524f13cba4d14 100644
--- a/services/companion/java/com/android/server/companion/virtual/VirtualDeviceImpl.java
+++ b/services/companion/java/com/android/server/companion/virtual/VirtualDeviceImpl.java
@@ -474,6 +474,13 @@ final class VirtualDeviceImpl extends IVirtualDevice.Stub
                                 + "this virtual device");
             }
         }
+
+        if (screenSize.x <= 0 || screenSize.y <= 0) {
+            throw new IllegalArgumentException(
+                    "Cannot create a virtual touchscreen, screen dimensions must be positive. Got: "
+                            + screenSize);
+        }
+
         final long token = Binder.clearCallingIdentity();
         try {
             mInputController.createTouchscreen(deviceName, vendorId, productId,
diff --git a/services/tests/servicestests/src/com/android/server/companion/virtual/VirtualDeviceManagerServiceTest.java b/services/tests/servicestests/src/com/android/server/companion/virtual/VirtualDeviceManagerServiceTest.java
index 5fda3d6b36ab5..5373ab591cc16 100644
--- a/services/tests/servicestests/src/com/android/server/companion/virtual/VirtualDeviceManagerServiceTest.java
+++ b/services/tests/servicestests/src/com/android/server/companion/virtual/VirtualDeviceManagerServiceTest.java
@@ -418,6 +418,35 @@ public class VirtualDeviceManagerServiceTest {
                         VENDOR_ID, PRODUCT_ID, BINDER, new Point(WIDTH, HEIGHT)));
     }
 
+    @Test
+    public void createVirtualTouchscreen_zeroDisplayDimension_failsIllegalArgumentException() {
+        mDeviceImpl.mVirtualDisplayIds.add(DISPLAY_ID);
+        Point size = new Point(0, 0);
+        assertThrows(IllegalArgumentException.class,
+                () -> mDeviceImpl.createVirtualTouchscreen(DISPLAY_ID, DEVICE_NAME, VENDOR_ID,
+                        PRODUCT_ID, BINDER, size));
+    }
+
+    @Test
+    public void createVirtualTouchscreen_negativeDisplayDimension_failsIllegalArgumentException() {
+        mDeviceImpl.mVirtualDisplayIds.add(DISPLAY_ID);
+        Point size = new Point(-100, -100);
+        assertThrows(IllegalArgumentException.class,
+                () -> mDeviceImpl.createVirtualTouchscreen(DISPLAY_ID, DEVICE_NAME, VENDOR_ID,
+                        PRODUCT_ID, BINDER, size));
+    }
+
+    @Test
+    public void createVirtualTouchscreen_positiveDisplayDimension_successful() {
+        mDeviceImpl.mVirtualDisplayIds.add(DISPLAY_ID);
+        Point size = new Point(600, 800);
+        mDeviceImpl.createVirtualTouchscreen(DISPLAY_ID, DEVICE_NAME, VENDOR_ID, PRODUCT_ID, BINDER,
+                size);
+        assertWithMessage(
+                "Virtual touchscreen should create input device descriptor on successful creation.")
+                .that(mInputController.mInputDeviceDescriptors).isNotEmpty();
+    }
+
     @Test
     public void onAudioSessionStarting_noDisplay_failsSecurityException() {
         assertThrows(SecurityException.class,