1 /* 2 * Copyright (C) 2015 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.statementservice; 18 19 import android.content.BroadcastReceiver; 20 import android.content.Context; 21 import android.content.Intent; 22 import android.content.pm.PackageManager; 23 import android.content.pm.PackageManager.NameNotFoundException; 24 import android.os.Bundle; 25 import android.os.Handler; 26 import android.os.ResultReceiver; 27 import android.util.Log; 28 import android.util.Patterns; 29 30 import com.android.statementservice.retriever.Utils; 31 32 import java.net.MalformedURLException; 33 import java.net.URL; 34 import java.util.ArrayList; 35 import java.util.Collections; 36 import java.util.List; 37 import java.util.regex.Pattern; 38 39 /** 40 * Receives {@link Intent#ACTION_INTENT_FILTER_NEEDS_VERIFICATION} broadcast and calls 41 * {@link DirectStatementService} to verify the request. Calls 42 * {@link PackageManager#verifyIntentFilter} to notify {@link PackageManager} the result of the 43 * verification. 44 * 45 * This implementation of the API will send a HTTP request for each host specified in the query. 46 * To avoid overwhelming the network at app install time, {@code MAX_HOSTS_PER_REQUEST} limits 47 * the maximum number of hosts in a query. If a query contains more than 48 * {@code MAX_HOSTS_PER_REQUEST} hosts, it will fail immediately without making any HTTP request 49 * and call {@link PackageManager#verifyIntentFilter} with 50 * {@link PackageManager#INTENT_FILTER_VERIFICATION_FAILURE}. 51 */ 52 public final class IntentFilterVerificationReceiver extends BroadcastReceiver { 53 private static final String TAG = IntentFilterVerificationReceiver.class.getSimpleName(); 54 55 private static final Integer MAX_HOSTS_PER_REQUEST = 10; 56 57 private static final String HANDLE_ALL_URLS_RELATION 58 = "delegate_permission/common.handle_all_urls"; 59 60 private static final String ANDROID_ASSET_FORMAT = "{\"namespace\": \"android_app\", " 61 + "\"package_name\": \"%s\", \"sha256_cert_fingerprints\": [\"%s\"]}"; 62 private static final String WEB_ASSET_FORMAT = "{\"namespace\": \"web\", \"site\": \"%s\"}"; 63 private static final Pattern ANDROID_PACKAGE_NAME_PATTERN = 64 Pattern.compile("^[a-zA-Z_][a-zA-Z0-9_]*(\\.[a-zA-Z_][a-zA-Z0-9_]*)*$"); 65 private static final String TOO_MANY_HOSTS_FORMAT = 66 "Request contains %d hosts which is more than the allowed %d."; 67 68 private static void sendErrorToPackageManager(PackageManager packageManager, 69 int verificationId) { 70 packageManager.verifyIntentFilter(verificationId, 71 PackageManager.INTENT_FILTER_VERIFICATION_FAILURE, 72 Collections.<String>emptyList()); 73 } 74 75 @Override 76 public void onReceive(Context context, Intent intent) { 77 final String action = intent.getAction(); 78 if (Intent.ACTION_INTENT_FILTER_NEEDS_VERIFICATION.equals(action)) { 79 Bundle inputExtras = intent.getExtras(); 80 if (inputExtras != null) { 81 Intent serviceIntent = new Intent(context, DirectStatementService.class); 82 serviceIntent.setAction(DirectStatementService.CHECK_ALL_ACTION); 83 84 int verificationId = inputExtras.getInt( 85 PackageManager.EXTRA_INTENT_FILTER_VERIFICATION_ID); 86 String scheme = inputExtras.getString( 87 PackageManager.EXTRA_INTENT_FILTER_VERIFICATION_URI_SCHEME); 88 String hosts = inputExtras.getString( 89 PackageManager.EXTRA_INTENT_FILTER_VERIFICATION_HOSTS); 90 String packageName = inputExtras.getString( 91 PackageManager.EXTRA_INTENT_FILTER_VERIFICATION_PACKAGE_NAME); 92 93 Log.i(TAG, "Verify IntentFilter for " + hosts); 94 95 Bundle extras = new Bundle(); 96 extras.putString(DirectStatementService.EXTRA_RELATION, HANDLE_ALL_URLS_RELATION); 97 98 String[] hostList = hosts.split(" "); 99 if (hostList.length > MAX_HOSTS_PER_REQUEST) { 100 Log.w(TAG, String.format(TOO_MANY_HOSTS_FORMAT, 101 hostList.length, MAX_HOSTS_PER_REQUEST)); 102 sendErrorToPackageManager(context.getPackageManager(), verificationId); 103 return; 104 } 105 106 try { 107 ArrayList<String> sourceAssets = new ArrayList<String>(); 108 for (String host : hostList) { 109 sourceAssets.add(createWebAssetString(scheme, host)); 110 } 111 extras.putStringArrayList(DirectStatementService.EXTRA_SOURCE_ASSET_DESCRIPTORS, 112 sourceAssets); 113 } catch (MalformedURLException e) { 114 Log.w(TAG, "Error when processing input host: " + e.getMessage()); 115 sendErrorToPackageManager(context.getPackageManager(), verificationId); 116 return; 117 } 118 try { 119 extras.putString(DirectStatementService.EXTRA_TARGET_ASSET_DESCRIPTOR, 120 createAndroidAssetString(context, packageName)); 121 } catch (NameNotFoundException e) { 122 Log.w(TAG, "Error when processing input Android package: " + e.getMessage()); 123 sendErrorToPackageManager(context.getPackageManager(), verificationId); 124 return; 125 } 126 extras.putParcelable(DirectStatementService.EXTRA_RESULT_RECEIVER, 127 new IsAssociatedResultReceiver( 128 new Handler(), context.getPackageManager(), verificationId)); 129 130 serviceIntent.putExtras(extras); 131 context.startService(serviceIntent); 132 } 133 } else { 134 Log.w(TAG, "Intent action not supported: " + action); 135 } 136 } 137 138 private String createAndroidAssetString(Context context, String packageName) 139 throws NameNotFoundException { 140 if (!ANDROID_PACKAGE_NAME_PATTERN.matcher(packageName).matches()) { 141 throw new NameNotFoundException("Input package name is not valid."); 142 } 143 144 List<String> certFingerprints = 145 Utils.getCertFingerprintsFromPackageManager(packageName, context); 146 147 return String.format(ANDROID_ASSET_FORMAT, packageName, 148 Utils.joinStrings("\", \"", certFingerprints)); 149 } 150 151 private String createWebAssetString(String scheme, String host) throws MalformedURLException { 152 if (!Patterns.DOMAIN_NAME.matcher(host).matches()) { 153 throw new MalformedURLException("Input host is not valid."); 154 } 155 if (!scheme.equals("http") && !scheme.equals("https")) { 156 throw new MalformedURLException("Input scheme is not valid."); 157 } 158 159 return String.format(WEB_ASSET_FORMAT, new URL(scheme, host, "").toString()); 160 } 161 162 /** 163 * Receives the result of {@code StatementService.CHECK_ACTION} from 164 * {@link DirectStatementService} and passes it back to {@link PackageManager}. 165 */ 166 private static class IsAssociatedResultReceiver extends ResultReceiver { 167 168 private final int mVerificationId; 169 private final PackageManager mPackageManager; 170 171 public IsAssociatedResultReceiver(Handler handler, PackageManager packageManager, 172 int verificationId) { 173 super(handler); 174 mVerificationId = verificationId; 175 mPackageManager = packageManager; 176 } 177 178 @Override 179 protected void onReceiveResult(int resultCode, Bundle resultData) { 180 if (resultCode == DirectStatementService.RESULT_SUCCESS) { 181 if (resultData.getBoolean(DirectStatementService.IS_ASSOCIATED)) { 182 mPackageManager.verifyIntentFilter(mVerificationId, 183 PackageManager.INTENT_FILTER_VERIFICATION_SUCCESS, 184 Collections.<String>emptyList()); 185 } else { 186 mPackageManager.verifyIntentFilter(mVerificationId, 187 PackageManager.INTENT_FILTER_VERIFICATION_FAILURE, 188 resultData.getStringArrayList(DirectStatementService.FAILED_SOURCES)); 189 } 190 } else { 191 sendErrorToPackageManager(mPackageManager, mVerificationId); 192 } 193 } 194 } 195 } 196
