Allow USE_RESTRICTED_NETWORKS for registerSystemDefaultNetworkCallback

Some callers (e.g. iwlan) need to learn about system default
network but they cannot have NETWORK_SETTINGS permission.
To allow them to use this API but prevent from misuse by
unprivileged apps, enforce USE_RESTRICTED_NETWORKS for this API.

Test: atest com.android.server.ConnectivityServiceTest#testRegisterPrivilegedDefaultCallbacksRequireNetworkSettings android.net.cts.ConnectivityManagerTest#testRegisterNetworkCallback
Fix: 242456635
Change-Id: I80ab27445af874328c9c0f4814a8fbf035ae5df4

framework/api/module-lib-current.txt

@@ -15,7 +15,7 @@ package android.net {
     method @Nullable @RequiresPermission(anyOf={android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK, android.Manifest.permission.NETWORK_STACK, android.Manifest.permission.NETWORK_SETTINGS}) public android.net.LinkProperties getRedactedLinkPropertiesForPackage(@NonNull android.net.LinkProperties, int, @NonNull String);
     method @Nullable @RequiresPermission(anyOf={android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK, android.Manifest.permission.NETWORK_STACK, android.Manifest.permission.NETWORK_SETTINGS}) public android.net.NetworkCapabilities getRedactedNetworkCapabilitiesForPackage(@NonNull android.net.NetworkCapabilities, int, @NonNull String);
     method @RequiresPermission(anyOf={android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK, android.Manifest.permission.NETWORK_SETTINGS}) public void registerDefaultNetworkCallbackForUid(int, @NonNull android.net.ConnectivityManager.NetworkCallback, @NonNull android.os.Handler);
-    method @RequiresPermission(anyOf={android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK, android.Manifest.permission.NETWORK_SETTINGS}) public void registerSystemDefaultNetworkCallback(@NonNull android.net.ConnectivityManager.NetworkCallback, @NonNull android.os.Handler);
+    method @RequiresPermission(anyOf={android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK, android.Manifest.permission.NETWORK_SETTINGS, android.Manifest.permission.CONNECTIVITY_USE_RESTRICTED_NETWORKS}) public void registerSystemDefaultNetworkCallback(@NonNull android.net.ConnectivityManager.NetworkCallback, @NonNull android.os.Handler);
     method @RequiresPermission(anyOf={android.Manifest.permission.NETWORK_SETTINGS, android.Manifest.permission.NETWORK_STACK, android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK}) public void removeUidFromMeteredNetworkAllowList(int);
     method @RequiresPermission(anyOf={android.Manifest.permission.NETWORK_SETTINGS, android.Manifest.permission.NETWORK_STACK, android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK}) public void removeUidFromMeteredNetworkDenyList(int);
     method @RequiresPermission(anyOf={android.Manifest.permission.NETWORK_SETTINGS, android.Manifest.permission.NETWORK_STACK, android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK}) public void replaceFirewallChain(int, @NonNull int[]);

framework/src/android/net/ConnectivityManager.java

@@ -4786,7 +4786,8 @@ public class ConnectivityManager {
     @SuppressLint({"ExecutorRegistration", "PairedRegistration"})
     @RequiresPermission(anyOf = {
             NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK,
-            android.Manifest.permission.NETWORK_SETTINGS})
+            android.Manifest.permission.NETWORK_SETTINGS,
+            android.Manifest.permission.CONNECTIVITY_USE_RESTRICTED_NETWORKS})
     public void registerSystemDefaultNetworkCallback(@NonNull NetworkCallback networkCallback,
             @NonNull Handler handler) {
         CallbackHandler cbHandler = new CallbackHandler(handler);

service/src/com/android/server/ConnectivityService.java

@@ -2800,6 +2800,13 @@ public class ConnectivityService extends IConnectivityManager.Stub
                 NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK);
     }
 
+    private void enforceSettingsOrUseRestrictedNetworksPermission() {
+        enforceAnyPermissionOf(mContext,
+                android.Manifest.permission.NETWORK_SETTINGS,
+                NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK,
+                Manifest.permission.CONNECTIVITY_USE_RESTRICTED_NETWORKS);
+    }
+
     private void enforceNetworkFactoryPermission() {
         // TODO: Check for the BLUETOOTH_STACK permission once that is in the API surface.
         if (UserHandle.getAppId(getCallingUid()) == Process.BLUETOOTH_UID) return;
@@ -6592,7 +6599,7 @@ public class ConnectivityService extends IConnectivityManager.Stub
                 enforceAccessPermission();
                 break;
             case TRACK_SYSTEM_DEFAULT:
-                enforceSettingsPermission();
+                enforceSettingsOrUseRestrictedNetworksPermission();
                 networkCapabilities = new NetworkCapabilities(defaultNc);
                 break;
             case BACKGROUND_REQUEST:

tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java

@@ -1044,12 +1044,22 @@ public class ConnectivityManagerTest {
         final TestNetworkCallback bestMatchingCallback = new TestNetworkCallback();
         final Handler h = new Handler(Looper.getMainLooper());
         if (TestUtils.shouldTestSApis()) {
+            assertThrows(SecurityException.class, () ->
+                    registerSystemDefaultNetworkCallback(systemDefaultCallback, h));
             runWithShellPermissionIdentity(() -> {
                 registerSystemDefaultNetworkCallback(systemDefaultCallback, h);
                 registerDefaultNetworkCallbackForUid(Process.myUid(), perUidCallback, h);
             }, NETWORK_SETTINGS);
             registerBestMatchingNetworkCallback(makeDefaultRequest(), bestMatchingCallback, h);
         }
+        if (TestUtils.shouldTestTApis()) {
+            // Verify registerSystemDefaultNetworkCallback can be accessed via
+            // CONNECTIVITY_USE_RESTRICTED_NETWORKS permission.
+            final TestNetworkCallback systemDefaultCallback2 = new TestNetworkCallback();
+            runWithShellPermissionIdentity(() ->
+                    registerSystemDefaultNetworkCallback(systemDefaultCallback2, h),
+                    CONNECTIVITY_USE_RESTRICTED_NETWORKS);
+        }
 
         Network wifiNetwork = null;
         mCtsNetUtils.ensureWifiConnected();

tests/unit/java/com/android/server/ConnectivityServiceTest.java

@@ -5121,9 +5121,10 @@ public class ConnectivityServiceTest {
     }
 
     @Test
-    public void testRegisterPrivilegedDefaultCallbacksRequireNetworkSettings() throws Exception {
+    public void testRegisterPrivilegedDefaultCallbacksRequirePermissions() throws Exception {
         mCellNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_CELLULAR);
         mCellNetworkAgent.connect(false /* validated */);
+        mServiceContext.setPermission(CONNECTIVITY_USE_RESTRICTED_NETWORKS, PERMISSION_DENIED);
 
         final Handler handler = new Handler(ConnectivityThread.getInstanceLooper());
         final TestNetworkCallback callback = new TestNetworkCallback();
@@ -5134,6 +5135,12 @@ public class ConnectivityServiceTest {
                 () -> mCm.registerDefaultNetworkCallbackForUid(APP1_UID, callback, handler));
         callback.assertNoCallback();
 
+        mServiceContext.setPermission(CONNECTIVITY_USE_RESTRICTED_NETWORKS, PERMISSION_GRANTED);
+        mCm.registerSystemDefaultNetworkCallback(callback, handler);
+        mServiceContext.setPermission(CONNECTIVITY_USE_RESTRICTED_NETWORKS, PERMISSION_DENIED);
+        callback.expectAvailableCallbacksUnvalidated(mCellNetworkAgent);
+        mCm.unregisterNetworkCallback(callback);
+
         mServiceContext.setPermission(NETWORK_SETTINGS, PERMISSION_GRANTED);
         mCm.registerSystemDefaultNetworkCallback(callback, handler);
         callback.expectAvailableCallbacksUnvalidated(mCellNetworkAgent);