From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Kevin Jeon <kevinjeon@google.com>
Date: Fri, 17 Feb 2023 20:17:54 +0000
Subject: [PATCH] Update Traceur to check admin user status

This change updates Traceur to check for admin user privileges wherever
a developer options check occurs. This is intended to address the case
in which developer options (a global setting not differentiated on
current user privileges) being enabled would allow guest users to open
Traceur through a 3P app and view its trace files. This would previously
be possible even when ADB debugging was disabled by the admin user.

Traceur now listens for user changes so that its document root
(containing traces) is enabled/disabled based on the new user's admin
status.

This change also includes a partial fix for a previous less-severe
security vulnerability (developer options checks; terminating ongoing
traces if the state of developer options changes). The entire fix is not
included because the full vulnerability did not exist in this branch.

Because Traceur is a platform app in R, a separate change to grant
MANAGE_USERS access in the privapp permissions allowlist is /not/
required (as in S).

Test: On a local CF build (cf_x86_64_phone-userdebug), explictly
      enable multi-user + apply aosp/1625022 and check that:
      - CtsIntentSignatureTestCases passes (b/270791503)
      - TraceurUiTests passes
      - Traceur cannot be opened through 'am start' on a guest account
      - Opening Files on a guest account no longer shows a System Traces
        folder (even if Traceur's onCreate is somehow called)
      - System tracing no longer appears in settings for guests
Bug: 262243665
Bug: 262244249
Bug: 204992293
Bug: 160155846
Ignore-AOSP-First: Internal-first security fix
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:0c0b30d30dfad851cdce35e1b9097b62fffabc5f)
Merged-In: I14ee42d18802e7869bae8cb437c4d0b65dbea999
Change-Id: I14ee42d18802e7869bae8cb437c4d0b65dbea999
---
 AndroidManifest.xml                              |  3 +++
 src/com/google/android/traceur/MainActivity.java | 16 ++++++++++++++++
 .../google/android/traceur/SearchProvider.java   |  7 +++++--
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index 42a4296..101e623 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -26,6 +26,9 @@
     <!-- Used for adding the Quick Settings tile to the status bar. -->
     <uses-permission android:name="android.permission.STATUS_BAR" />
 
+    <!-- Used to check that the current user is an admin user. -->
+    <uses-permission android:name="android.permission.MANAGE_USERS" />
+
     <!-- Declare Android TV support. -->
     <uses-feature android:name="android.software.leanback" android:required="false" />
 
diff --git a/src/com/google/android/traceur/MainActivity.java b/src/com/google/android/traceur/MainActivity.java
index a8c8a2b..ef1577e 100644
--- a/src/com/google/android/traceur/MainActivity.java
+++ b/src/com/google/android/traceur/MainActivity.java
@@ -16,7 +16,9 @@ package com.android.traceur;
  */
 
 import android.app.Activity;
+import android.provider.Settings;
 import android.os.Bundle;
+import android.os.UserManager;
 
 public class MainActivity extends Activity {
     @Override
@@ -24,4 +26,18 @@ public class MainActivity extends Activity {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity);
     }
+
+    @Override
+    protected void onStart() {
+        super.onStart();
+        boolean developerOptionsIsEnabled =
+            Settings.Global.getInt(getContentResolver(),
+                Settings.Global.DEVELOPMENT_SETTINGS_ENABLED, 0) != 0;
+        boolean isAdminUser = getApplicationContext()
+                .getSystemService(UserManager.class).isAdminUser();
+
+        if (!developerOptionsIsEnabled || !isAdminUser) {
+            finish();
+        }
+    }
 }
diff --git a/src/com/google/android/traceur/SearchProvider.java b/src/com/google/android/traceur/SearchProvider.java
index 202d2b0..9098e89 100644
--- a/src/com/google/android/traceur/SearchProvider.java
+++ b/src/com/google/android/traceur/SearchProvider.java
@@ -31,6 +31,7 @@ import android.content.Context;
 import android.content.Intent;
 import android.database.Cursor;
 import android.database.MatrixCursor;
+import android.os.UserManager;
 import android.provider.SearchIndexablesProvider;
 import android.provider.Settings;
 
@@ -69,9 +70,11 @@ public class SearchProvider extends SearchIndexablesProvider {
         boolean developerOptionsIsEnabled =
             Settings.Global.getInt(getContext().getContentResolver(),
                 Settings.Global.DEVELOPMENT_SETTINGS_ENABLED, 0) != 0;
+        boolean isAdminUser = getContext().getSystemService(UserManager.class).isAdminUser();
 
-        // If developer options is not enabled, System Tracing shouldn't be searchable.
-        if (!developerOptionsIsEnabled) {
+        // System Tracing shouldn't be searchable if developer options are not enabled or if the
+        // user is not an admin.
+        if (!developerOptionsIsEnabled || !isAdminUser) {
             MatrixCursor cursor = new MatrixCursor(NON_INDEXABLES_KEYS_COLUMNS);
             Object[] row = new Object[] {getContext().getString(R.string.system_tracing)};
             cursor.addRow(row);