Listen to permission changes in permission monitor

Bug: 369646309
Test: atest
ConnectivityCoverageTests:android.net.connectivity.com.android.server.connectivity.PermissionMonitorTest

Change-Id: I23c524baaee6b9b06a855fb811906e5189ef03fd
diff --git a/common/flags.aconfig b/common/flags.aconfig
index 60a827b..5f279fa 100644
--- a/common/flags.aconfig
+++ b/common/flags.aconfig
@@ -165,3 +165,12 @@
   bug: "372936361"
   is_fixed_read_only: true
 }
+
+flag {
+  name: "restrict_local_network"
+  is_exported: true
+  namespace: "android_core_networking"
+  description: "Flag for controlling access to the local network behind a new runtime permission. Requires ConnectivityCompatChanges.RESTRICT_LOCAL_NETWORK to enable feature."
+  bug: "365139289"
+  is_fixed_read_only: true
+}
diff --git a/service/src/com/android/server/connectivity/PermissionMonitor.java b/service/src/com/android/server/connectivity/PermissionMonitor.java
index beaa174..0d388e8 100755
--- a/service/src/com/android/server/connectivity/PermissionMonitor.java
+++ b/service/src/com/android/server/connectivity/PermissionMonitor.java
@@ -31,6 +31,7 @@
 import static android.net.INetd.PERMISSION_UNINSTALLED;
 import static android.net.INetd.PERMISSION_UPDATE_DEVICE_STATS;
 import static android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK;
+import static android.net.connectivity.ConnectivityCompatChanges.RESTRICT_LOCAL_NETWORK;
 import static android.os.Process.INVALID_UID;
 import static android.os.Process.SYSTEM_UID;
 
@@ -38,6 +39,7 @@
 
 import android.annotation.NonNull;
 import android.annotation.Nullable;
+import android.app.compat.CompatChanges;
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
@@ -70,6 +72,7 @@
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.util.IndentingPrintWriter;
 import com.android.modules.utils.build.SdkLevel;
+import com.android.net.flags.Flags;
 import com.android.net.module.util.CollectionUtils;
 import com.android.net.module.util.SharedLog;
 import com.android.networkstack.apishim.ProcessShimImpl;
@@ -279,6 +282,12 @@
         mContext = context;
         mBpfNetMaps = bpfNetMaps;
         mThread = thread;
+        if (Flags.restrictLocalNetwork()) {
+            // This listener should finish registration by the time the system has completed
+            // boot setup such that any changes to runtime permissions for local network
+            // restrictions can only occur after this registration has completed.
+            mPackageManager.addOnPermissionsChangeListener(new PermissionChangeListener());
+        }
     }
 
     private void ensureRunningOnHandlerThread() {
@@ -1311,4 +1320,19 @@
     private static void loge(String s, Throwable e) {
         Log.e(TAG, s, e);
     }
+
+    private class PermissionChangeListener implements PackageManager.OnPermissionsChangedListener {
+        @Override
+        public void onPermissionsChanged(int uid) {
+            // RESTRICT_LOCAL_NETWORK is a compat change that is enabled when developers manually
+            // opt-in to this change, or when the app's targetSdkVersion is greater than 36.
+            // The RESTRICT_LOCAL_NETWORK compat change is used here instead of the
+            // Flags.restrictLocalNetwork() is used to offer the feature to devices, but it will
+            // only be enforced when develoeprs choose to enable it.
+            // TODO(b/394567896): Update compat change checks
+            if (CompatChanges.isChangeEnabled(RESTRICT_LOCAL_NETWORK, uid)) {
+                // TODO(b/388803658): Update network permissions and record change
+            }
+        }
+    }
 }
diff --git a/tests/integration/src/com/android/server/net/integrationtests/ConnectivityServiceIntegrationTest.kt b/tests/integration/src/com/android/server/net/integrationtests/ConnectivityServiceIntegrationTest.kt
index 06bdca6..375d604 100644
--- a/tests/integration/src/com/android/server/net/integrationtests/ConnectivityServiceIntegrationTest.kt
+++ b/tests/integration/src/com/android/server/net/integrationtests/ConnectivityServiceIntegrationTest.kt
@@ -16,6 +16,7 @@
 
 package com.android.server.net.integrationtests
 
+import android.Manifest.permission
 import android.app.usage.NetworkStatsManager
 import android.content.ComponentName
 import android.content.Context
@@ -66,6 +67,7 @@
 import com.android.testutils.DeviceInfoUtils
 import com.android.testutils.RecorderCallback.CallbackEntry.LinkPropertiesChanged
 import com.android.testutils.TestableNetworkCallback
+import com.android.testutils.runAsShell
 import com.android.testutils.tryTest
 import java.util.function.BiConsumer
 import java.util.function.Consumer
@@ -208,7 +210,9 @@
         networkStackClient = TestNetworkStackClient(realContext)
         networkStackClient.start()
 
-        service = TestConnectivityService(TestDependencies())
+        service = runAsShell(permission.OBSERVE_GRANT_REVOKE_PERMISSIONS) {
+            TestConnectivityService(TestDependencies())
+        }
         cm = ConnectivityManager(context, service)
         context.addMockSystemService(Context.CONNECTIVITY_SERVICE, cm)
         context.addMockSystemService(Context.NETWORK_STATS_SERVICE, statsManager)
diff --git a/tests/unit/java/com/android/server/connectivity/PermissionMonitorTest.java b/tests/unit/java/com/android/server/connectivity/PermissionMonitorTest.java
index 5bde31a..55c68b7 100644
--- a/tests/unit/java/com/android/server/connectivity/PermissionMonitorTest.java
+++ b/tests/unit/java/com/android/server/connectivity/PermissionMonitorTest.java
@@ -22,6 +22,7 @@
 import static android.Manifest.permission.CONNECTIVITY_USE_RESTRICTED_NETWORKS;
 import static android.Manifest.permission.INTERNET;
 import static android.Manifest.permission.NETWORK_STACK;
+import static android.Manifest.permission.OBSERVE_GRANT_REVOKE_PERMISSIONS;
 import static android.Manifest.permission.UPDATE_DEVICE_STATS;
 import static android.content.pm.ApplicationInfo.PRIVATE_FLAG_OEM;
 import static android.content.pm.ApplicationInfo.PRIVATE_FLAG_PRODUCT;
@@ -41,6 +42,7 @@
 import static android.os.Process.SYSTEM_UID;
 
 import static com.android.server.connectivity.PermissionMonitor.isHigherNetworkPermission;
+import static com.android.testutils.TestPermissionUtil.runAsShell;
 
 import static junit.framework.Assert.fail;
 
@@ -1235,8 +1237,10 @@
         // Use the real context as this test must ensure the *real* system package holds the
         // necessary permission.
         final Context realContext = InstrumentationRegistry.getContext();
-        final PermissionMonitor monitor = new PermissionMonitor(
-                realContext, mNetdService, mBpfNetMaps, mHandlerThread);
+        final PermissionMonitor monitor = runAsShell(
+                OBSERVE_GRANT_REVOKE_PERMISSIONS,
+                () -> new PermissionMonitor(realContext, mNetdService, mBpfNetMaps, mHandlerThread)
+        );
         final PackageManager manager = realContext.getPackageManager();
         final PackageInfo systemInfo = manager.getPackageInfo(REAL_SYSTEM_PACKAGE_NAME,
                 GET_PERMISSIONS | MATCH_ANY_USER);