| /* |
| * Copyright 2017 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.server.net.watchlist; |
| |
| import android.annotation.Nullable; |
| import android.util.Log; |
| import android.util.proto.ProtoOutputStream; |
| |
| import com.android.internal.annotations.VisibleForTesting; |
| import com.android.internal.util.HexDump; |
| import com.android.service.NetworkWatchlistReportProto; |
| import com.android.service.NetworkWatchlistAppResultProto; |
| |
| import java.io.ByteArrayOutputStream; |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.List; |
| import java.util.Map; |
| |
| /** |
| * Helper class to encode and generate serialized DP encoded watchlist proto report. |
| */ |
| class ReportEncoder { |
| |
| private static final String TAG = "ReportEncoder"; |
| |
| // Report version number, as file format / parameters can be changed in later version, we need |
| // to have versioning on watchlist report format |
| private static final int REPORT_VERSION = 1; |
| |
| private static final int WATCHLIST_HASH_SIZE = 32; |
| |
| /** |
| * Apply DP on watchlist results, and generate a serialized watchlist report ready to store |
| * in DropBox. |
| */ |
| @Nullable |
| static byte[] encodeWatchlistReport(WatchlistConfig config, byte[] userSecret, |
| List<String> appDigestList, WatchlistReportDbHelper.AggregatedResult aggregatedResult) { |
| Map<String, Boolean> resultMap = PrivacyUtils.createDpEncodedReportMap( |
| config.isConfigSecure(), userSecret, appDigestList, aggregatedResult); |
| return serializeReport(config, resultMap); |
| } |
| |
| /** |
| * Convert DP encoded watchlist report into proto format. |
| * |
| * @param encodedReportMap DP encoded watchlist report. |
| * @return Watchlist report in proto format, which will be shared in Dropbox. Null if |
| * watchlist report cannot be generated. |
| */ |
| @Nullable |
| @VisibleForTesting |
| static byte[] serializeReport(WatchlistConfig config, |
| Map<String, Boolean> encodedReportMap) { |
| // TODO: Handle watchlist config changed case |
| final byte[] watchlistHash = config.getWatchlistConfigHash(); |
| if (watchlistHash == null) { |
| Log.e(TAG, "No watchlist hash"); |
| return null; |
| } |
| if (watchlistHash.length != WATCHLIST_HASH_SIZE) { |
| Log.e(TAG, "Unexpected hash length"); |
| return null; |
| } |
| final ByteArrayOutputStream reportOutputStream = new ByteArrayOutputStream(); |
| final ProtoOutputStream proto = new ProtoOutputStream(reportOutputStream); |
| |
| // Set report version to report |
| proto.write(NetworkWatchlistReportProto.REPORT_VERSION, REPORT_VERSION); |
| proto.write(NetworkWatchlistReportProto.WATCHLIST_CONFIG_HASH, |
| HexDump.toHexString(watchlistHash)); |
| |
| // Set app digest, encoded_isPha pair to report |
| for (Map.Entry<String, Boolean> entry : encodedReportMap.entrySet()) { |
| String key = entry.getKey(); |
| byte[] digest = HexDump.hexStringToByteArray(key); |
| boolean encodedResult = entry.getValue(); |
| long token = proto.start(NetworkWatchlistReportProto.APP_RESULT); |
| proto.write(NetworkWatchlistAppResultProto.APP_DIGEST, key); |
| proto.write(NetworkWatchlistAppResultProto.ENCODED_RESULT, encodedResult); |
| proto.end(token); |
| } |
| proto.flush(); |
| return reportOutputStream.toByteArray(); |
| } |
| } |