From 9f5f1a26c184b0ad3ab87853f11b4aa346a866d5 Mon Sep 17 00:00:00 2001
From: Gavin Corkery <gavincorkery@google.com>
Date: Fri, 13 May 2022 17:36:08 +0000
Subject: [PATCH] Add DeviceConfig flag for enforcing receiver restrictions

Allows the restrictions on the SDK sandbox registering broadcast
receivers to be enabled or disabled depending on the value of a
DeviceConfig property in the Sdk Sandbox namespace.

Test: atest SdkSandboxRestrictionsHostTest
Bug: 229199225
Change-Id: Id6194b2b90bdf8eaa3b0e59cf8dff0b735d663bb
---
 .../server/am/ActivityManagerService.java     | 54 ++++++++++++++++++-
 1 file changed, 53 insertions(+), 1 deletion(-)

diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index f6e8bc826153d..aa510e7717eb6 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -1530,6 +1530,8 @@ public class ActivityManagerService extends IActivityManager.Stub
     // Encapsulates the global setting "hidden_api_blacklist_exemptions"
     final HiddenApiSettings mHiddenApiBlacklist;
 
+    final SdkSandboxSettings mSdkSandboxSettings;
+
     private final PlatformCompat mPlatformCompat;
 
     PackageManagerInternal mPackageManagerInt;
@@ -2235,6 +2237,53 @@ public class ActivityManagerService extends IActivityManager.Stub
         }
     }
 
+    /**
+     * Handles settings related to the enforcement of SDK sandbox restrictions.
+     */
+    static class SdkSandboxSettings implements DeviceConfig.OnPropertiesChangedListener {
+
+        private final Context mContext;
+        private final Object mLock = new Object();
+
+        @GuardedBy("mLock")
+        private boolean mEnforceBroadcastReceiverRestrictions;
+
+        /**
+         * Property to enforce broadcast receiver restrictions for SDK sandbox processes. If the
+         * value of this property is {@code true}, the restrictions will be enforced.
+         */
+        public static final String ENFORCE_BROADCAST_RECEIVER_RESTRICTIONS =
+                "enforce_broadcast_receiver_restrictions";
+
+        SdkSandboxSettings(Context context) {
+            mContext = context;
+        }
+
+        void registerObserver() {
+            synchronized (mLock) {
+                mEnforceBroadcastReceiverRestrictions = DeviceConfig.getBoolean(
+                        DeviceConfig.NAMESPACE_SDK_SANDBOX,
+                        ENFORCE_BROADCAST_RECEIVER_RESTRICTIONS, false);
+                DeviceConfig.addOnPropertiesChangedListener(DeviceConfig.NAMESPACE_SDK_SANDBOX,
+                        mContext.getMainExecutor(), this);
+            }
+        }
+
+        @Override
+        public void onPropertiesChanged(DeviceConfig.Properties properties) {
+            synchronized (mLock) {
+                mEnforceBroadcastReceiverRestrictions = properties.getBoolean(
+                        ENFORCE_BROADCAST_RECEIVER_RESTRICTIONS, false);
+            }
+        }
+
+        boolean isBroadcastReceiverRestrictionsEnforced() {
+            synchronized (mLock) {
+                return mEnforceBroadcastReceiverRestrictions;
+            }
+        }
+    }
+
     AppOpsManager getAppOpsManager() {
         if (mAppOpsManager == null) {
             mAppOpsManager = mContext.getSystemService(AppOpsManager.class);
@@ -2287,6 +2336,7 @@ public class ActivityManagerService extends IActivityManager.Stub
         mProcStartHandlerThread = null;
         mProcStartHandler = null;
         mHiddenApiBlacklist = null;
+        mSdkSandboxSettings = null;
         mFactoryTest = FACTORY_TEST_OFF;
         mUgmInternal = LocalServices.getService(UriGrantsManagerInternal.class);
         mInternal = new LocalService();
@@ -2406,6 +2456,7 @@ public class ActivityManagerService extends IActivityManager.Stub
         mAtmInternal = LocalServices.getService(ActivityTaskManagerInternal.class);
 
         mHiddenApiBlacklist = new HiddenApiSettings(mHandler, mContext);
+        mSdkSandboxSettings = new SdkSandboxSettings(mContext);
 
         Watchdog.getInstance().addMonitor(this);
         Watchdog.getInstance().addThread(mHandler);
@@ -7911,6 +7962,7 @@ public class ActivityManagerService extends IActivityManager.Stub
         final boolean alwaysFinishActivities =
                 Settings.Global.getInt(resolver, ALWAYS_FINISH_ACTIVITIES, 0) != 0;
         mHiddenApiBlacklist.registerObserver();
+        mSdkSandboxSettings.registerObserver();
         mPlatformCompat.registerContentObserver();
 
         mAppProfiler.retrieveSettings();
@@ -12940,7 +12992,7 @@ public class ActivityManagerService extends IActivityManager.Stub
         // Allow Sandbox process to register only unexported receivers.
         if ((flags & Context.RECEIVER_NOT_EXPORTED) != 0) {
             enforceNotIsolatedCaller("registerReceiver");
-        } else {
+        } else if (mSdkSandboxSettings.isBroadcastReceiverRestrictionsEnforced()) {
             enforceNotIsolatedOrSdkSandboxCaller("registerReceiver");
         }
         ArrayList<Intent> stickyIntents = null;