Route EncryptedLocalTransport KV backup/restore through encryption code

Bug: 142227548
Test: Verify the device boots successfully
      Verify EncryptedLocalTransport APK is present
      Verify manual backup/restore using bmgr for LocalTransport and EncryptedLocalTransport
      For LocalTransport (unencrypted) and EncryptedLocalTransport:
        atest CtsBackupTestCases
        atest CtsBackupHostTestCases
        atest GtsBackupTestCases
        atest GtsBackupHostTestCases


Change-Id: Iac3a8a50d7f761442a4b784cfba3a980e900dd7f

packages/EncryptedLocalTransport/Android.bp

@@ -0,0 +1,27 @@
+//
+// Copyright (C) 2019 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.
+//
+
+android_app {
+    name: "EncryptedLocalTransport",
+    srcs: ["src/**/*.java"],
+    optimize: {
+        proguard_flags_files: ["proguard.flags"],
+    },
+    static_libs: ["LocalTransport"],
+    platform_apis: true,
+    certificate: "platform",
+    privileged: true,
+}

packages/EncryptedLocalTransport/AndroidManifest.xml

@@ -0,0 +1,36 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+/*
+ * Copyright (c) 2019 Google Inc.
+ *
+ * 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.
+ */
+-->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+      package="com.android.encryptedlocaltransport"
+      android:sharedUserId="android.uid.system" >
+
+
+    <application android:allowBackup="false" >
+        <!-- This service does not need to be exported because it shares uid with the system server
+        which is the only client. -->
+        <service android:name=".EncryptedLocalTransportService"
+                 android:permission="android.permission.CONFIRM_FULL_BACKUP"
+                 android:exported="false">
+            <intent-filter>
+                <action android:name="android.backup.TRANSPORT_HOST" />
+            </intent-filter>
+        </service>
+
+    </application>
+</manifest>

packages/EncryptedLocalTransport/proguard.flags

@@ -0,0 +1,2 @@
+-keep class com.android.localTransport.EncryptedLocalTransport
+-keep class com.android.localTransport.EncryptedLocalTransportService

packages/EncryptedLocalTransport/src/com/android/encryptedlocaltransport/EncryptedLocalTransport.java

@@ -0,0 +1,109 @@
+/*
+ * Copyright (C) 2019 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 com.android.encryptedlocaltransport;
+
+import android.app.backup.BackupTransport;
+import android.app.backup.RestoreDescription;
+import android.content.Context;
+import android.content.pm.PackageInfo;
+import android.os.ParcelFileDescriptor;
+import android.system.ErrnoException;
+import android.system.Os;
+import android.system.StructStat;
+import android.util.Log;
+
+import com.android.localtransport.LocalTransport;
+import com.android.localtransport.LocalTransportParameters;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.nio.file.Files;
+import java.nio.file.StandardCopyOption;
+
+public class EncryptedLocalTransport extends LocalTransport {
+    private static final String TAG = "EncryptedLocalTransport";
+    private static final int BACKUP_BUFFER_SIZE = 32 * 1024; // 32 KB.
+
+    public EncryptedLocalTransport(Context context,
+            LocalTransportParameters parameters) {
+        super(context, parameters);
+    }
+
+    @Override
+    public int performBackup(
+            PackageInfo packageInfo, ParcelFileDescriptor data, int flags) {
+        File packageFile;
+        try {
+            StructStat stat = Os.fstat(data.getFileDescriptor());
+            if (stat.st_size > KEY_VALUE_BACKUP_SIZE_QUOTA) {
+                Log.w(TAG, "New datastore size " + stat.st_size
+                        + " exceeds quota " + KEY_VALUE_BACKUP_SIZE_QUOTA);
+                return TRANSPORT_QUOTA_EXCEEDED;
+            }
+        } catch (ErrnoException e) {
+            Log.w(TAG, "Failed to stat the backup input file: ", e);
+            return BackupTransport.TRANSPORT_ERROR;
+        }
+
+        clearBackupData(packageInfo);
+
+        try (InputStream in = new FileInputStream(data.getFileDescriptor())) {
+            packageFile = new File(mCurrentSetIncrementalDir, packageInfo.packageName);
+            Files.copy(in, packageFile.toPath(), StandardCopyOption.REPLACE_EXISTING);
+        } catch (IOException e) {
+            Log.w(TAG, "Failed to save backup data to file: ", e);
+            return BackupTransport.TRANSPORT_ERROR;
+        }
+
+        return TRANSPORT_OK;
+    }
+
+    @Override
+    public int getRestoreData(ParcelFileDescriptor outFd) {
+        if (mRestorePackages == null) {
+            throw new IllegalStateException("startRestore not called");
+        }
+        if (mRestorePackage < 0) {
+            throw new IllegalStateException("nextRestorePackage not called");
+        }
+        if (mRestoreType != RestoreDescription.TYPE_KEY_VALUE) {
+            throw new IllegalStateException("getRestoreData(fd) for non-key/value dataset");
+        }
+
+        try(OutputStream out = new FileOutputStream(outFd.getFileDescriptor())) {
+            File packageFile = new File(mRestoreSetIncrementalDir,
+                    mRestorePackages[mRestorePackage].packageName);
+            Files.copy(packageFile.toPath(), out);
+        } catch (IOException e) {
+            Log.d(TAG, "Failed to transfer restore data: " + e);
+            return BackupTransport.TRANSPORT_ERROR;
+        }
+
+        return BackupTransport.TRANSPORT_OK;
+    }
+
+    @Override
+    protected boolean hasRestoreDataForPackage(String packageName) {
+        File contents = (new File(mRestoreSetIncrementalDir, packageName));
+        return contents.exists() && contents.length() != 0;
+
+    }
+}

packages/EncryptedLocalTransport/src/com/android/encryptedlocaltransport/EncryptedLocalTransportService.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2019 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 com.android.encryptedlocaltransport;
+
+import android.app.Service;
+import android.content.Intent;
+import android.os.IBinder;
+
+import com.android.localtransport.LocalTransportParameters;
+
+public class EncryptedLocalTransportService extends Service {
+    private static EncryptedLocalTransport sTransport = null;
+
+    @Override
+    public void onCreate() {
+        if (sTransport == null) {
+            LocalTransportParameters parameters =
+                    new LocalTransportParameters(getMainThreadHandler(), getContentResolver());
+            sTransport = new EncryptedLocalTransport(this, parameters);
+        }
+        sTransport.getParameters().start();
+    }
+
+    @Override
+    public void onDestroy() {
+        sTransport.getParameters().stop();
+    }
+
+    @Override
+    public IBinder onBind(Intent intent) {
+        return sTransport.getBinder();
+    }
+}