From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Edgar Wang <edgarwang@google.com>
Date: Thu, 6 Jan 2022 20:53:48 +0800
Subject: [PATCH] Fix bypass CALL_PRIVILEGED permission in
 AppRestrictionsFragment

In onReceive of AppRestrictionsFragment.java, there is a possible way to
start a phone call without permissions due to a confused deputy.
This could lead to local escalation of privilege with no additional
execution privileges needed.

We should not allow the restrictionsIntent to startActivity simply
because it resolves to multiple activities.
Instead, we should call resolveActivity and check the result's package
name is same as current package name, then it is safe to startActivity.

Bug: 200688991
Test: manual verify
Change-Id: Iaa2d3a9497c3266babe0789961befc9776a4db7a
Merged-In: Iaa2d3a9497c3266babe0789961befc9776a4db7a
(cherry picked from commit 359512cd9553c940af3c9045b856647b7529731a)
(cherry picked from commit f57d75f127fe96e91250585208a339763f1a2253)
Merged-In:Iaa2d3a9497c3266babe0789961befc9776a4db7a
---
 .../users/AppRestrictionsFragment.java        | 24 +++++++++++++------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/src/com/android/settings/users/AppRestrictionsFragment.java b/src/com/android/settings/users/AppRestrictionsFragment.java
index f72bf9e97bf..ee2114219e7 100644
--- a/src/com/android/settings/users/AppRestrictionsFragment.java
+++ b/src/com/android/settings/users/AppRestrictionsFragment.java
@@ -17,6 +17,7 @@
 package com.android.settings.users;
 
 import android.app.Activity;
+import android.content.ActivityNotFoundException;
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
@@ -44,6 +45,7 @@ import android.support.v7.preference.Preference.OnPreferenceChangeListener;
 import android.support.v7.preference.Preference.OnPreferenceClickListener;
 import android.support.v7.preference.PreferenceGroup;
 import android.support.v7.preference.PreferenceViewHolder;
+import android.util.EventLog;
 import android.util.Log;
 import android.view.View;
 import android.view.View.OnClickListener;
@@ -634,7 +636,15 @@ public class AppRestrictionsFragment extends SettingsPreferenceFragment implemen
             } else if (restrictionsIntent != null) {
                 preference.setRestrictions(restrictions);
                 if (invokeIfCustom && AppRestrictionsFragment.this.isResumed()) {
-                    assertSafeToStartCustomActivity(restrictionsIntent);
+                    try {
+                        assertSafeToStartCustomActivity(restrictionsIntent);
+                    } catch (ActivityNotFoundException | SecurityException e) {
+                        // return without startActivity
+                        Log.e(TAG, "Cannot start restrictionsIntent " + e);
+                        EventLog.writeEvent(0x534e4554, "200688991", -1 /* UID */, "");
+                        return;
+                    }
+
                     int requestCode = generateCustomActivityRequestCode(
                             RestrictionsResultReceiver.this.preference);
                     AppRestrictionsFragment.this.startActivityForResult(
@@ -648,14 +658,14 @@ public class AppRestrictionsFragment extends SettingsPreferenceFragment implemen
             if (intent.getPackage() != null && intent.getPackage().equals(packageName)) {
                 return;
             }
-            // Activity can be started if intent resolves to multiple activities
-            List<ResolveInfo> resolveInfos = AppRestrictionsFragment.this.mPackageManager
-                    .queryIntentActivities(intent, 0 /* no flags */);
-            if (resolveInfos.size() != 1) {
-                return;
+            ResolveInfo resolveInfo = mPackageManager.resolveActivity(
+                    intent, PackageManager.MATCH_DEFAULT_ONLY);
+
+            if (resolveInfo == null) {
+                throw new ActivityNotFoundException("No result for resolving " + intent);
             }
             // Prevent potential privilege escalation
-            ActivityInfo activityInfo = resolveInfos.get(0).activityInfo;
+            ActivityInfo activityInfo = resolveInfo.activityInfo;
             if (!packageName.equals(activityInfo.packageName)) {
                 throw new SecurityException("Application " + packageName
                         + " is not allowed to start activity " + intent);