Robert Berry | 25f5135 | 2018-03-28 20:26:57 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2018 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.server.locksettings.recoverablekeystore.serialization; |
| 18 | |
| 19 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.CERTIFICATE_FACTORY_TYPE; |
| 20 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.NAMESPACE; |
| 21 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.OUTPUT_ENCODING; |
| 22 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.TAG_ALGORITHM; |
| 23 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.TAG_ALIAS; |
| 24 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.TAG_APPLICATION_KEY; |
| 25 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.TAG_APPLICATION_KEYS; |
Robert Berry | 5658837 | 2018-03-29 12:07:17 +0100 | [diff] [blame] | 26 | |
| 27 | import static com.android.server.locksettings.recoverablekeystore.serialization |
| 28 | .KeyChainSnapshotSchema.TAG_BACKEND_PUBLIC_KEY; |
Robert Berry | 25f5135 | 2018-03-28 20:26:57 +0100 | [diff] [blame] | 29 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.TAG_COUNTER_ID; |
| 30 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.TAG_RECOVERY_KEY_MATERIAL; |
| 31 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.TAG_KEY_CHAIN_PROTECTION_PARAMS; |
| 32 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.TAG_KEY_CHAIN_PROTECTION_PARAMS_LIST; |
| 33 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.TAG_KEY_CHAIN_SNAPSHOT; |
| 34 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.TAG_KEY_DERIVATION_PARAMS; |
| 35 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.TAG_KEY_MATERIAL; |
| 36 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.TAG_LOCK_SCREEN_UI_TYPE; |
| 37 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.TAG_MAX_ATTEMPTS; |
| 38 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.TAG_MEMORY_DIFFICULTY; |
| 39 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.TAG_SALT; |
| 40 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.TAG_SERVER_PARAMS; |
| 41 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.TAG_SNAPSHOT_VERSION; |
| 42 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.TAG_TRUSTED_HARDWARE_CERT_PATH; |
| 43 | import static com.android.server.locksettings.recoverablekeystore.serialization.KeyChainSnapshotSchema.TAG_USER_SECRET_TYPE; |
| 44 | |
| 45 | import android.security.keystore.recovery.KeyChainProtectionParams; |
| 46 | import android.security.keystore.recovery.KeyChainSnapshot; |
| 47 | import android.security.keystore.recovery.KeyDerivationParams; |
| 48 | import android.security.keystore.recovery.WrappedApplicationKey; |
| 49 | import android.util.Base64; |
| 50 | import android.util.Xml; |
| 51 | |
| 52 | import java.io.ByteArrayInputStream; |
| 53 | import java.io.IOException; |
| 54 | import java.io.InputStream; |
| 55 | import java.security.cert.CertPath; |
| 56 | import java.security.cert.CertificateException; |
| 57 | import java.security.cert.CertificateFactory; |
| 58 | import java.util.ArrayList; |
| 59 | import java.util.List; |
| 60 | import java.util.Locale; |
| 61 | |
| 62 | import org.xmlpull.v1.XmlPullParser; |
| 63 | import org.xmlpull.v1.XmlPullParserException; |
| 64 | |
| 65 | /** |
| 66 | * Deserializes a {@link android.security.keystore.recovery.KeyChainSnapshot} instance from XML. |
| 67 | */ |
| 68 | public class KeyChainSnapshotDeserializer { |
| 69 | |
| 70 | /** |
| 71 | * Deserializes a {@link KeyChainSnapshot} instance from the XML in the {@code inputStream}. |
| 72 | * |
| 73 | * @throws IOException if there is an IO error reading from the stream. |
| 74 | * @throws KeyChainSnapshotParserException if the XML does not conform to the expected XML for |
| 75 | * a snapshot. |
| 76 | */ |
| 77 | public static KeyChainSnapshot deserialize(InputStream inputStream) |
| 78 | throws KeyChainSnapshotParserException, IOException { |
| 79 | try { |
| 80 | return deserializeInternal(inputStream); |
| 81 | } catch (XmlPullParserException e) { |
| 82 | throw new KeyChainSnapshotParserException("Malformed KeyChainSnapshot XML", e); |
| 83 | } |
| 84 | } |
| 85 | |
| 86 | private static KeyChainSnapshot deserializeInternal(InputStream inputStream) throws IOException, |
| 87 | XmlPullParserException, KeyChainSnapshotParserException { |
| 88 | XmlPullParser parser = Xml.newPullParser(); |
| 89 | parser.setInput(inputStream, OUTPUT_ENCODING); |
| 90 | |
| 91 | parser.nextTag(); |
| 92 | parser.require(XmlPullParser.START_TAG, NAMESPACE, TAG_KEY_CHAIN_SNAPSHOT); |
| 93 | |
| 94 | KeyChainSnapshot.Builder builder = new KeyChainSnapshot.Builder(); |
| 95 | while (parser.next() != XmlPullParser.END_TAG) { |
| 96 | if (parser.getEventType() != XmlPullParser.START_TAG) { |
| 97 | continue; |
| 98 | } |
| 99 | |
| 100 | String name = parser.getName(); |
| 101 | |
| 102 | switch (name) { |
| 103 | case TAG_SNAPSHOT_VERSION: |
| 104 | builder.setSnapshotVersion(readIntTag(parser, TAG_SNAPSHOT_VERSION)); |
| 105 | break; |
| 106 | |
| 107 | case TAG_RECOVERY_KEY_MATERIAL: |
| 108 | builder.setEncryptedRecoveryKeyBlob( |
| 109 | readBlobTag(parser, TAG_RECOVERY_KEY_MATERIAL)); |
| 110 | break; |
| 111 | |
| 112 | case TAG_COUNTER_ID: |
| 113 | builder.setCounterId(readLongTag(parser, TAG_COUNTER_ID)); |
| 114 | break; |
| 115 | |
| 116 | case TAG_SERVER_PARAMS: |
| 117 | builder.setServerParams(readBlobTag(parser, TAG_SERVER_PARAMS)); |
| 118 | break; |
| 119 | |
| 120 | case TAG_MAX_ATTEMPTS: |
| 121 | builder.setMaxAttempts(readIntTag(parser, TAG_MAX_ATTEMPTS)); |
| 122 | break; |
| 123 | |
| 124 | case TAG_TRUSTED_HARDWARE_CERT_PATH: |
| 125 | try { |
| 126 | builder.setTrustedHardwareCertPath( |
| 127 | readCertPathTag(parser, TAG_TRUSTED_HARDWARE_CERT_PATH)); |
| 128 | } catch (CertificateException e) { |
| 129 | throw new KeyChainSnapshotParserException( |
| 130 | "Could not set trustedHardwareCertPath", e); |
| 131 | } |
| 132 | break; |
| 133 | |
Robert Berry | 5658837 | 2018-03-29 12:07:17 +0100 | [diff] [blame] | 134 | case TAG_BACKEND_PUBLIC_KEY: |
| 135 | builder.setTrustedHardwarePublicKey( |
| 136 | readBlobTag(parser, TAG_BACKEND_PUBLIC_KEY)); |
| 137 | break; |
| 138 | |
Robert Berry | 25f5135 | 2018-03-28 20:26:57 +0100 | [diff] [blame] | 139 | case TAG_KEY_CHAIN_PROTECTION_PARAMS_LIST: |
| 140 | builder.setKeyChainProtectionParams(readKeyChainProtectionParamsList(parser)); |
| 141 | break; |
| 142 | |
| 143 | case TAG_APPLICATION_KEYS: |
| 144 | builder.setWrappedApplicationKeys(readWrappedApplicationKeys(parser)); |
| 145 | break; |
| 146 | |
| 147 | default: |
| 148 | throw new KeyChainSnapshotParserException(String.format( |
| 149 | Locale.US, "Unexpected tag %s in keyChainSnapshot", name)); |
| 150 | } |
| 151 | } |
| 152 | |
| 153 | parser.require(XmlPullParser.END_TAG, NAMESPACE, TAG_KEY_CHAIN_SNAPSHOT); |
| 154 | try { |
| 155 | return builder.build(); |
| 156 | } catch (NullPointerException e) { |
| 157 | throw new KeyChainSnapshotParserException("Failed to build KeyChainSnapshot", e); |
| 158 | } |
| 159 | } |
| 160 | |
| 161 | private static List<WrappedApplicationKey> readWrappedApplicationKeys(XmlPullParser parser) |
| 162 | throws IOException, XmlPullParserException, KeyChainSnapshotParserException { |
| 163 | parser.require(XmlPullParser.START_TAG, NAMESPACE, TAG_APPLICATION_KEYS); |
| 164 | ArrayList<WrappedApplicationKey> keys = new ArrayList<>(); |
| 165 | while (parser.next() != XmlPullParser.END_TAG) { |
| 166 | if (parser.getEventType() != XmlPullParser.START_TAG) { |
| 167 | continue; |
| 168 | } |
| 169 | keys.add(readWrappedApplicationKey(parser)); |
| 170 | } |
| 171 | parser.require(XmlPullParser.END_TAG, NAMESPACE, TAG_APPLICATION_KEYS); |
| 172 | return keys; |
| 173 | } |
| 174 | |
| 175 | private static WrappedApplicationKey readWrappedApplicationKey(XmlPullParser parser) |
| 176 | throws IOException, XmlPullParserException, KeyChainSnapshotParserException { |
| 177 | parser.require(XmlPullParser.START_TAG, NAMESPACE, TAG_APPLICATION_KEY); |
| 178 | WrappedApplicationKey.Builder builder = new WrappedApplicationKey.Builder(); |
| 179 | while (parser.next() != XmlPullParser.END_TAG) { |
| 180 | if (parser.getEventType() != XmlPullParser.START_TAG) { |
| 181 | continue; |
| 182 | } |
| 183 | |
| 184 | String name = parser.getName(); |
| 185 | |
| 186 | switch (name) { |
| 187 | case TAG_ALIAS: |
| 188 | builder.setAlias(readStringTag(parser, TAG_ALIAS)); |
| 189 | break; |
| 190 | |
| 191 | case TAG_KEY_MATERIAL: |
| 192 | builder.setEncryptedKeyMaterial(readBlobTag(parser, TAG_KEY_MATERIAL)); |
| 193 | break; |
| 194 | |
| 195 | default: |
| 196 | throw new KeyChainSnapshotParserException(String.format( |
| 197 | Locale.US, "Unexpected tag %s in wrappedApplicationKey", name)); |
| 198 | } |
| 199 | } |
| 200 | parser.require(XmlPullParser.END_TAG, NAMESPACE, TAG_APPLICATION_KEY); |
| 201 | |
| 202 | try { |
| 203 | return builder.build(); |
| 204 | } catch (NullPointerException e) { |
| 205 | throw new KeyChainSnapshotParserException("Failed to build WrappedApplicationKey", e); |
| 206 | } |
| 207 | } |
| 208 | |
| 209 | private static List<KeyChainProtectionParams> readKeyChainProtectionParamsList( |
| 210 | XmlPullParser parser) throws IOException, XmlPullParserException, |
| 211 | KeyChainSnapshotParserException { |
| 212 | parser.require(XmlPullParser.START_TAG, NAMESPACE, TAG_KEY_CHAIN_PROTECTION_PARAMS_LIST); |
| 213 | |
| 214 | ArrayList<KeyChainProtectionParams> keyChainProtectionParamsList = new ArrayList<>(); |
| 215 | while (parser.next() != XmlPullParser.END_TAG) { |
| 216 | if (parser.getEventType() != XmlPullParser.START_TAG) { |
| 217 | continue; |
| 218 | } |
| 219 | keyChainProtectionParamsList.add(readKeyChainProtectionParams(parser)); |
| 220 | } |
| 221 | |
| 222 | parser.require(XmlPullParser.END_TAG, NAMESPACE, TAG_KEY_CHAIN_PROTECTION_PARAMS_LIST); |
| 223 | return keyChainProtectionParamsList; |
| 224 | } |
| 225 | |
| 226 | private static KeyChainProtectionParams readKeyChainProtectionParams(XmlPullParser parser) |
| 227 | throws IOException, XmlPullParserException, KeyChainSnapshotParserException { |
| 228 | parser.require(XmlPullParser.START_TAG, NAMESPACE, TAG_KEY_CHAIN_PROTECTION_PARAMS); |
| 229 | |
| 230 | KeyChainProtectionParams.Builder builder = new KeyChainProtectionParams.Builder(); |
| 231 | while (parser.next() != XmlPullParser.END_TAG) { |
| 232 | if (parser.getEventType() != XmlPullParser.START_TAG) { |
| 233 | continue; |
| 234 | } |
| 235 | |
| 236 | String name = parser.getName(); |
| 237 | |
| 238 | switch (name) { |
| 239 | case TAG_LOCK_SCREEN_UI_TYPE: |
| 240 | builder.setLockScreenUiFormat(readIntTag(parser, TAG_LOCK_SCREEN_UI_TYPE)); |
| 241 | break; |
| 242 | |
| 243 | case TAG_USER_SECRET_TYPE: |
| 244 | builder.setUserSecretType(readIntTag(parser, TAG_USER_SECRET_TYPE)); |
| 245 | break; |
| 246 | |
| 247 | case TAG_KEY_DERIVATION_PARAMS: |
| 248 | builder.setKeyDerivationParams(readKeyDerivationParams(parser)); |
| 249 | break; |
| 250 | |
| 251 | default: |
| 252 | throw new KeyChainSnapshotParserException(String.format( |
| 253 | Locale.US, |
| 254 | "Unexpected tag %s in keyChainProtectionParams", |
| 255 | name)); |
| 256 | |
| 257 | } |
| 258 | } |
| 259 | |
| 260 | parser.require(XmlPullParser.END_TAG, NAMESPACE, TAG_KEY_CHAIN_PROTECTION_PARAMS); |
| 261 | |
| 262 | try { |
| 263 | return builder.build(); |
| 264 | } catch (NullPointerException e) { |
| 265 | throw new KeyChainSnapshotParserException( |
| 266 | "Failed to build KeyChainProtectionParams", e); |
| 267 | } |
| 268 | } |
| 269 | |
| 270 | private static KeyDerivationParams readKeyDerivationParams(XmlPullParser parser) |
| 271 | throws XmlPullParserException, IOException, KeyChainSnapshotParserException { |
| 272 | parser.require(XmlPullParser.START_TAG, NAMESPACE, TAG_KEY_DERIVATION_PARAMS); |
| 273 | |
| 274 | int memoryDifficulty = -1; |
| 275 | int algorithm = -1; |
| 276 | byte[] salt = null; |
| 277 | |
| 278 | while (parser.next() != XmlPullParser.END_TAG) { |
| 279 | if (parser.getEventType() != XmlPullParser.START_TAG) { |
| 280 | continue; |
| 281 | } |
| 282 | |
| 283 | String name = parser.getName(); |
| 284 | |
| 285 | switch (name) { |
| 286 | case TAG_MEMORY_DIFFICULTY: |
| 287 | memoryDifficulty = readIntTag(parser, TAG_MEMORY_DIFFICULTY); |
| 288 | break; |
| 289 | |
| 290 | case TAG_ALGORITHM: |
| 291 | algorithm = readIntTag(parser, TAG_ALGORITHM); |
| 292 | break; |
| 293 | |
| 294 | case TAG_SALT: |
| 295 | salt = readBlobTag(parser, TAG_SALT); |
| 296 | break; |
| 297 | |
| 298 | default: |
| 299 | throw new KeyChainSnapshotParserException( |
| 300 | String.format( |
| 301 | Locale.US, |
| 302 | "Unexpected tag %s in keyDerivationParams", |
| 303 | name)); |
| 304 | } |
| 305 | } |
| 306 | |
| 307 | if (salt == null) { |
| 308 | throw new KeyChainSnapshotParserException("salt was not set in keyDerivationParams"); |
| 309 | } |
| 310 | |
| 311 | KeyDerivationParams keyDerivationParams = null; |
| 312 | |
| 313 | switch (algorithm) { |
| 314 | case KeyDerivationParams.ALGORITHM_SHA256: |
| 315 | keyDerivationParams = KeyDerivationParams.createSha256Params(salt); |
| 316 | break; |
| 317 | |
| 318 | case KeyDerivationParams.ALGORITHM_SCRYPT: |
| 319 | keyDerivationParams = KeyDerivationParams.createScryptParams( |
| 320 | salt, memoryDifficulty); |
| 321 | break; |
| 322 | |
| 323 | default: |
| 324 | throw new KeyChainSnapshotParserException( |
| 325 | "Unknown algorithm in keyDerivationParams"); |
| 326 | } |
| 327 | |
| 328 | parser.require(XmlPullParser.END_TAG, NAMESPACE, TAG_KEY_DERIVATION_PARAMS); |
| 329 | return keyDerivationParams; |
| 330 | } |
| 331 | |
| 332 | private static int readIntTag(XmlPullParser parser, String tagName) |
| 333 | throws IOException, XmlPullParserException, KeyChainSnapshotParserException { |
| 334 | parser.require(XmlPullParser.START_TAG, NAMESPACE, tagName); |
| 335 | String text = readText(parser); |
| 336 | parser.require(XmlPullParser.END_TAG, NAMESPACE, tagName); |
| 337 | try { |
| 338 | return Integer.valueOf(text); |
| 339 | } catch (NumberFormatException e) { |
| 340 | throw new KeyChainSnapshotParserException( |
| 341 | String.format( |
| 342 | Locale.US, "%s expected int but got '%s'", tagName, text), e); |
| 343 | } |
| 344 | } |
| 345 | |
| 346 | private static long readLongTag(XmlPullParser parser, String tagName) |
| 347 | throws IOException, XmlPullParserException, KeyChainSnapshotParserException { |
| 348 | parser.require(XmlPullParser.START_TAG, NAMESPACE, tagName); |
| 349 | String text = readText(parser); |
| 350 | parser.require(XmlPullParser.END_TAG, NAMESPACE, tagName); |
| 351 | try { |
| 352 | return Long.valueOf(text); |
| 353 | } catch (NumberFormatException e) { |
| 354 | throw new KeyChainSnapshotParserException( |
| 355 | String.format( |
| 356 | Locale.US, "%s expected long but got '%s'", tagName, text), e); |
| 357 | } |
| 358 | } |
| 359 | |
| 360 | private static String readStringTag(XmlPullParser parser, String tagName) |
| 361 | throws IOException, XmlPullParserException { |
| 362 | parser.require(XmlPullParser.START_TAG, NAMESPACE, tagName); |
| 363 | String text = readText(parser); |
| 364 | parser.require(XmlPullParser.END_TAG, NAMESPACE, tagName); |
| 365 | return text; |
| 366 | } |
| 367 | |
| 368 | private static byte[] readBlobTag(XmlPullParser parser, String tagName) |
| 369 | throws IOException, XmlPullParserException, KeyChainSnapshotParserException { |
| 370 | parser.require(XmlPullParser.START_TAG, NAMESPACE, tagName); |
| 371 | String text = readText(parser); |
| 372 | parser.require(XmlPullParser.END_TAG, NAMESPACE, tagName); |
| 373 | |
| 374 | try { |
| 375 | return Base64.decode(text, /*flags=*/ Base64.DEFAULT); |
| 376 | } catch (IllegalArgumentException e) { |
| 377 | throw new KeyChainSnapshotParserException( |
| 378 | String.format( |
| 379 | Locale.US, |
| 380 | "%s expected base64 encoded bytes but got '%s'", |
| 381 | tagName, text), e); |
| 382 | } |
| 383 | } |
| 384 | |
| 385 | private static CertPath readCertPathTag(XmlPullParser parser, String tagName) |
| 386 | throws IOException, XmlPullParserException, KeyChainSnapshotParserException { |
| 387 | byte[] bytes = readBlobTag(parser, tagName); |
| 388 | try { |
| 389 | return CertificateFactory.getInstance(CERTIFICATE_FACTORY_TYPE) |
| 390 | .generateCertPath(new ByteArrayInputStream(bytes)); |
| 391 | } catch (CertificateException e) { |
| 392 | throw new KeyChainSnapshotParserException("Could not parse CertPath in tag " + tagName, |
| 393 | e); |
| 394 | } |
| 395 | } |
| 396 | |
| 397 | private static String readText(XmlPullParser parser) |
| 398 | throws IOException, XmlPullParserException { |
| 399 | String result = ""; |
| 400 | if (parser.next() == XmlPullParser.TEXT) { |
| 401 | result = parser.getText(); |
| 402 | parser.nextTag(); |
| 403 | } |
| 404 | return result; |
| 405 | } |
| 406 | |
| 407 | // Statics only |
| 408 | private KeyChainSnapshotDeserializer() {} |
| 409 | } |