Don't expose raw IBinder APIs.

APIs should not expose raw IBinder objects.

Fix: 184735751
Test: builds, boots
Test: atest CtsNetTestCases:android.net.cts.ConnectivityManagerTest
Test: atest CtsNetTestCases:android.net.cts.DnsResolverTest
Change-Id: Ia0c4170def31123f0b79318fec2cfe02e4fcd3bf

core/api/system-current.txt

@@ -6092,10 +6092,6 @@ package android.metrics {
 
 package android.net {
 
-  public class DnsResolverServiceManager {
-    method @NonNull @RequiresPermission(android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK) public static android.os.IBinder getService(@NonNull android.content.Context);
-  }
-
   public class EthernetManager {
     method @NonNull @RequiresPermission(anyOf={android.Manifest.permission.NETWORK_STACK, android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK}) public android.net.EthernetManager.TetheredInterfaceRequest requestTetheredInterface(@NonNull java.util.concurrent.Executor, @NonNull android.net.EthernetManager.TetheredInterfaceCallback);
   }

core/java/android/net/DnsResolverServiceManager.java

@@ -1,63 +0,0 @@
-/*
- * Copyright (C) 2020 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package android.net;
-
-import android.annotation.NonNull;
-import android.annotation.RequiresPermission;
-import android.annotation.SystemApi;
-import android.content.Context;
-import android.os.IBinder;
-import android.os.ServiceManager;
-
-import java.util.Objects;
-
-/**
- * Provides a way to obtain the DnsResolver binder objects.
- *
- * @hide
- */
-@SystemApi
-public class DnsResolverServiceManager {
-    /**
-     * Name to retrieve a {@link android.net.IDnsResolver} IBinder.
-     */
-    private static final String DNS_RESOLVER_SERVICE = "dnsresolver";
-
-    private DnsResolverServiceManager() {}
-
-    /**
-     * Get an {@link IBinder} representing the DnsResolver stable AIDL interface
-     *
-     * @param context the context for permission check.
-     * @return {@link android.net.IDnsResolver} IBinder.
-     */
-    @NonNull
-    @RequiresPermission(NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK)
-    public static IBinder getService(@NonNull final Context context) {
-        Objects.requireNonNull(context);
-        context.enforceCallingOrSelfPermission(NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK,
-                "DnsResolverServiceManager");
-        try {
-            return ServiceManager.getServiceOrThrow(DNS_RESOLVER_SERVICE);
-        } catch (ServiceManager.ServiceNotFoundException e) {
-            // Catch ServiceManager#ServiceNotFoundException and rethrow IllegalStateException
-            // because ServiceManager#ServiceNotFoundException is @hide so that it can't be listed
-            // on the system api. Thus, rethrow IllegalStateException if dns resolver service cannot
-            // be found.
-            throw new IllegalStateException("Cannot find dns resolver service.");
-        }
-    }
-}

packages/Connectivity/framework/src/android/net/ConnectivityFrameworkInitializer.java

@@ -68,5 +68,11 @@ public final class ConnectivityFrameworkInitializer {
                     return cm.startOrGetTestNetworkManager();
                 }
         );
+
+        SystemServiceRegistry.registerContextAwareService(
+                DnsResolverServiceManager.DNS_RESOLVER_SERVICE,
+                DnsResolverServiceManager.class,
+                (context, serviceBinder) -> new DnsResolverServiceManager(serviceBinder)
+        );
     }
 }

packages/Connectivity/framework/src/android/net/DnsResolverServiceManager.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.net;
+
+import android.annotation.NonNull;
+import android.os.IBinder;
+
+/**
+ * Provides a way to obtain the DnsResolver binder objects.
+ *
+ * @hide
+ */
+public class DnsResolverServiceManager {
+    /** Service name for the DNS resolver. Keep in sync with DnsResolverService.h */
+    public static final String DNS_RESOLVER_SERVICE = "dnsresolver";
+
+    private final IBinder mResolver;
+
+    DnsResolverServiceManager(IBinder resolver) {
+        mResolver = resolver;
+    }
+
+    /**
+     * Get an {@link IBinder} representing the DnsResolver stable AIDL interface
+     *
+     * @return {@link android.net.IDnsResolver} IBinder.
+     */
+    @NonNull
+    public IBinder getService() {
+        return mResolver;
+    }
+}

services/core/java/com/android/server/ConnectivityService.java

@@ -616,7 +616,9 @@ public class ConnectivityService extends IConnectivityManager.Stub
     }
 
     private static IDnsResolver getDnsResolver(Context context) {
-        return IDnsResolver.Stub.asInterface(DnsResolverServiceManager.getService(context));
+        final DnsResolverServiceManager dsm = context.getSystemService(
+                DnsResolverServiceManager.class);
+        return IDnsResolver.Stub.asInterface(dsm.getService());
     }
 
     /** Handler thread used for all of the handlers below. */