RecoveryController.java revision 3990ee1c9fcd8f801220edec94e6bef3009809b5
1/* 2 * Copyright (C) 2017 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 17package android.security.keystore.recovery; 18 19import android.annotation.NonNull; 20import android.annotation.Nullable; 21import android.annotation.RequiresPermission; 22import android.annotation.SystemApi; 23import android.app.KeyguardManager; 24import android.app.PendingIntent; 25import android.content.Context; 26import android.content.pm.PackageManager.NameNotFoundException; 27import android.os.RemoteException; 28import android.os.ServiceManager; 29import android.os.ServiceSpecificException; 30import android.security.KeyStore; 31import android.security.keystore.AndroidKeyStoreProvider; 32 33import com.android.internal.widget.ILockSettings; 34 35import java.security.Key; 36import java.security.UnrecoverableKeyException; 37import java.security.cert.CertPath; 38import java.security.cert.CertificateException; 39import java.security.cert.X509Certificate; 40import java.util.ArrayList; 41import java.util.List; 42import java.util.Map; 43 44/** 45 * Backs up cryptographic keys to remote secure hardware, encrypted with the user's lock screen. 46 * 47 * <p>A system app with the {@code android.permission.RECOVER_KEYSTORE} permission may generate or 48 * import recoverable keys using this class. To generate a key, the app must call 49 * {@link #generateKey(String)} with the desired alias for the key. This returns an AndroidKeyStore 50 * reference to a 256-bit {@link javax.crypto.SecretKey}, which can be used for AES/GCM/NoPadding. 51 * In order to get the same key again at a later time, the app can call {@link #getKey(String)} with 52 * the same alias. If a key is generated in this way the key's raw material is never directly 53 * exposed to the calling app. The system app may also import key material using 54 * {@link #importKey(String, byte[])}. The app may only generate and import keys for its own 55 * {@code uid}. 56 * 57 * <p>The same system app must also register a Recovery Agent to manage syncing recoverable keys to 58 * remote secure hardware. The Recovery Agent is a service that registers itself with the controller 59 * as follows: 60 * 61 * <ul> 62 * <li>Invokes {@link #initRecoveryService(String, byte[], byte[])} 63 * <ul> 64 * <li>The first argument is the alias of the root certificate used to verify trusted 65 * hardware modules. Each trusted hardware module must have a public key signed with this 66 * root of trust. Roots of trust must be shipped with the framework. The app can list all 67 * valid roots of trust by calling {@link #getRootCertificates()}. 68 * <li>The second argument is the UTF-8 bytes of the XML listing file. It lists the X509 69 * certificates containing the public keys of all available remote trusted hardware modules. 70 * Each of the X509 certificates can be validated against the chosen root of trust. 71 * <li>The third argument is the UTF-8 bytes of the XML signing file. The file contains a 72 * signature of the XML listing file. The signature can be validated against the chosen root 73 * of trust. 74 * </ul> 75 * <p>This will cause the controller to choose a random public key from the list. From then 76 * on the controller will attempt to sync the key chain with the trusted hardware module to whom 77 * that key belongs. 78 * <li>Invokes {@link #setServerParams(byte[])} with a byte string that identifies the device 79 * to a remote server. This server may act as the front-end to the trusted hardware modules. It 80 * is up to the Recovery Agent to decide how best to identify devices, but this could be, e.g., 81 * based on the <a href="https://developers.google.com/instance-id/">Instance ID</a> of the 82 * system app. 83 * <li>Invokes {@link #setRecoverySecretTypes(int[])} with a list of types of secret used to 84 * secure the recoverable key chain. For now only 85 * {@link KeyChainProtectionParams#TYPE_LOCKSCREEN} is supported. 86 * <li>Invokes {@link #setSnapshotCreatedPendingIntent(PendingIntent)} with a 87 * {@link PendingIntent} that is to be invoked whenever a new snapshot is created. Although the 88 * controller can create snapshots without the Recovery Agent registering this intent, it is a 89 * good idea to register the intent so that the Recovery Agent is able to sync this snapshot to 90 * the trusted hardware module as soon as it is available. 91 * </ul> 92 * 93 * <p>The trusted hardware module's public key MUST be generated on secure hardware with protections 94 * equivalent to those described in the 95 * <a href="https://developer.android.com/preview/features/security/ckv-whitepaper.html">Google 96 * Cloud Key Vault Service whitepaper</a>. The trusted hardware module itself must protect the key 97 * chain from brute-forcing using the methods also described in the whitepaper: i.e., it should 98 * limit the number of allowed attempts to enter the lock screen. If the number of attempts is 99 * exceeded the key material must no longer be recoverable. 100 * 101 * <p>A recoverable key chain snapshot is considered pending if any of the following conditions 102 * are met: 103 * 104 * <ul> 105 * <li>The system app mutates the key chain. i.e., generates, imports, or removes a key. 106 * <li>The user changes their lock screen. 107 * </ul> 108 * 109 * <p>Whenever the user unlocks their device, if a snapshot is pending, the Recovery Controller 110 * generates a new snapshot. It follows these steps to do so: 111 * 112 * <ul> 113 * <li>Generates a 256-bit AES key using {@link java.security.SecureRandom}. This is the 114 * Recovery Key. 115 * <li>Wraps the key material of all keys in the recoverable key chain with the Recovery Key. 116 * <li>Encrypts the Recovery Key with both the public key of the trusted hardware module and a 117 * symmetric key derived from the user's lock screen. 118 * </ul> 119 * 120 * <p>The controller then writes this snapshot to disk, and uses the {@link PendingIntent} that was 121 * set by the Recovery Agent during initialization to inform it that a new snapshot is available. 122 * The snapshot only contains keys for that Recovery Agent's {@code uid} - i.e., keys the agent's 123 * app itself generated. If multiple Recovery Agents exist on the device, each will be notified of 124 * their new snapshots, and each snapshots' keys will be only those belonging to the same 125 * {@code uid}. 126 * 127 * <p>The Recovery Agent retrieves its most recent snapshot by calling 128 * {@link #getKeyChainSnapshot()}. It syncs the snapshot to the remote server. The snapshot contains 129 * the public key used for encryption, which the server uses to forward the encrypted recovery key 130 * to the correct trusted hardware module. The snapshot also contains the server params, which are 131 * used to identify this device to the server. 132 * 133 * <p>The client uses the server params to identify a device whose key chain it wishes to restore. 134 * This may be on a different device to the device that originally synced the key chain. The client 135 * sends the server params identifying the previous device to the server. The server returns the 136 * X509 certificate identifying the trusted hardware module in which the encrypted Recovery Key is 137 * stored. It also returns some vault parameters identifying that particular Recovery Key to the 138 * trusted hardware module. And it also returns a vault challenge, which is used as part of the 139 * vault opening protocol to ensure the recovery claim is fresh. See the whitepaper for more 140 * details. 141 * 142 * <p>The key chain is recovered via a {@link RecoverySession}. A Recovery Agent creates one by 143 * invoking {@link #createRecoverySession()}. It then invokes 144 * {@link RecoverySession#start(String, CertPath, byte[], byte[], List)} with these arguments: 145 * 146 * <ul> 147 * <li>The alias of the root of trust used to verify the trusted hardware module. 148 * <li>The X509 certificate of the trusted hardware module. 149 * <li>The vault parameters used to identify the Recovery Key to the trusted hardware module. 150 * <li>The vault challenge, as issued by the trusted hardware module. 151 * <li>A list of secrets, corresponding to the secrets used to protect the key chain. At the 152 * moment this is a single {@link KeyChainProtectionParams} containing the lock screen of the 153 * device whose key chain is to be recovered. 154 * </ul> 155 * 156 * <p>This method returns a byte array containing the Recovery Claim, which can be issued to the 157 * remote trusted hardware module. It is encrypted with the trusted hardware module's public key 158 * (which has itself been certified with the root of trust). It also contains an ephemeral symmetric 159 * key generated for this recovery session, which the remote trusted hardware module uses to encrypt 160 * its responses. This is the Session Key. 161 * 162 * <p>If the lock screen provided is correct, the remote trusted hardware module decrypts one of the 163 * layers of lock-screen encryption from the Recovery Key. It then returns this key, encrypted with 164 * the Session Key to the Recovery Agent. As the Recovery Agent does not know the Session Key, it 165 * must then invoke {@link RecoverySession#recoverKeyChainSnapshot(byte[], List)} with the encrypted 166 * Recovery Key and the list of wrapped application keys. The controller then decrypts the layer of 167 * encryption provided by the Session Key, and uses the lock screen to decrypt the final layer of 168 * encryption. It then uses the Recovery Key to decrypt all of the wrapped application keys, and 169 * imports them into its own KeyStore. The Recovery Agent's app may then access these keys by 170 * calling {@link #getKey(String)}. Only this app's {@code uid} may access the keys that have been 171 * recovered. 172 * 173 * @hide 174 */ 175@SystemApi 176public class RecoveryController { 177 private static final String TAG = "RecoveryController"; 178 179 /** Key has been successfully synced. */ 180 public static final int RECOVERY_STATUS_SYNCED = 0; 181 /** Waiting for recovery agent to sync the key. */ 182 public static final int RECOVERY_STATUS_SYNC_IN_PROGRESS = 1; 183 /** Key cannot be synced. */ 184 public static final int RECOVERY_STATUS_PERMANENT_FAILURE = 3; 185 186 /** 187 * Failed because no snapshot is yet pending to be synced for the user. 188 * 189 * @hide 190 */ 191 public static final int ERROR_NO_SNAPSHOT_PENDING = 21; 192 193 /** 194 * Failed due to an error internal to the recovery service. This is unexpected and indicates 195 * either a problem with the logic in the service, or a problem with a dependency of the 196 * service (such as AndroidKeyStore). 197 * 198 * @hide 199 */ 200 public static final int ERROR_SERVICE_INTERNAL_ERROR = 22; 201 202 /** 203 * Failed because the user does not have a lock screen set. 204 * 205 * @hide 206 */ 207 public static final int ERROR_INSECURE_USER = 23; 208 209 /** 210 * Error thrown when attempting to use a recovery session that has since been closed. 211 * 212 * @hide 213 */ 214 public static final int ERROR_SESSION_EXPIRED = 24; 215 216 /** 217 * Failed because the format of the provided certificate is incorrect, e.g., cannot be decoded 218 * properly or misses necessary fields. 219 * 220 * <p>Note that this is different from {@link #ERROR_INVALID_CERTIFICATE}, which implies the 221 * certificate has a correct format but cannot be validated. 222 * 223 * @hide 224 */ 225 public static final int ERROR_BAD_CERTIFICATE_FORMAT = 25; 226 227 /** 228 * Error thrown if decryption failed. This might be because the tag is wrong, the key is wrong, 229 * the data has become corrupted, the data has been tampered with, etc. 230 * 231 * @hide 232 */ 233 public static final int ERROR_DECRYPTION_FAILED = 26; 234 235 /** 236 * Error thrown if the format of a given key is invalid. This might be because the key has a 237 * wrong length, invalid content, etc. 238 * 239 * @hide 240 */ 241 public static final int ERROR_INVALID_KEY_FORMAT = 27; 242 243 /** 244 * Failed because the provided certificate cannot be validated, e.g., is expired or has invalid 245 * signatures. 246 * 247 * <p>Note that this is different from {@link #ERROR_BAD_CERTIFICATE_FORMAT}, which denotes 248 * incorrect certificate formats, e.g., due to wrong encoding or structure. 249 * 250 * @hide 251 */ 252 public static final int ERROR_INVALID_CERTIFICATE = 28; 253 254 255 /** 256 * Failed because the provided certificate contained serial version which is lower that the 257 * version device is already initialized with. It is not possible to downgrade serial version of 258 * the provided certificate. 259 * 260 * @hide 261 */ 262 public static final int ERROR_DOWNGRADE_CERTIFICATE = 29; 263 264 private final ILockSettings mBinder; 265 private final KeyStore mKeyStore; 266 267 private RecoveryController(ILockSettings binder, KeyStore keystore) { 268 mBinder = binder; 269 mKeyStore = keystore; 270 } 271 272 /** 273 * Internal method used by {@code RecoverySession}. 274 * 275 * @hide 276 */ 277 ILockSettings getBinder() { 278 return mBinder; 279 } 280 281 /** 282 * Gets a new instance of the class. 283 */ 284 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 285 @NonNull public static RecoveryController getInstance(@NonNull Context context) { 286 ILockSettings lockSettings = 287 ILockSettings.Stub.asInterface(ServiceManager.getService("lock_settings")); 288 return new RecoveryController(lockSettings, KeyStore.getInstance()); 289 } 290 291 /** 292 * Checks whether the recoverable key store is currently available. 293 * 294 * <p>If it returns true, the device must currently be using a screen lock that is supported for 295 * use with the recoverable key store, i.e. AOSP PIN, pattern or password. 296 */ 297 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 298 public static boolean isRecoverableKeyStoreEnabled(@NonNull Context context) { 299 KeyguardManager keyguardManager = context.getSystemService(KeyguardManager.class); 300 return keyguardManager != null && keyguardManager.isDeviceSecure(); 301 } 302 303 /** 304 * @deprecated Use {@link #initRecoveryService(String, byte[], byte[])} instead. 305 * @removed 306 */ 307 @Deprecated 308 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 309 public void initRecoveryService( 310 @NonNull String rootCertificateAlias, @NonNull byte[] signedPublicKeyList) 311 throws CertificateException, InternalRecoveryServiceException { 312 try { 313 mBinder.initRecoveryService(rootCertificateAlias, signedPublicKeyList); 314 } catch (RemoteException e) { 315 throw e.rethrowFromSystemServer(); 316 } catch (ServiceSpecificException e) { 317 if (e.errorCode == ERROR_BAD_CERTIFICATE_FORMAT 318 || e.errorCode == ERROR_INVALID_CERTIFICATE) { 319 throw new CertificateException("Invalid certificate for recovery service", e); 320 } 321 throw wrapUnexpectedServiceSpecificException(e); 322 } 323 } 324 325 /** 326 * Initializes the recovery service for the calling application. The detailed steps should be: 327 * <ol> 328 * <li>Parse {@code signatureFile} to get relevant information. 329 * <li>Validate the signer's X509 certificate, contained in {@code signatureFile}, against 330 * the root certificate pre-installed in the OS and chosen by {@code 331 * rootCertificateAlias}. 332 * <li>Verify the public-key signature, contained in {@code signatureFile}, and verify it 333 * against the entire {@code certificateFile}. 334 * <li>Parse {@code certificateFile} to get relevant information. 335 * <li>Check the serial number, contained in {@code certificateFile}, and skip the following 336 * steps if the serial number is not larger than the one previously stored. 337 * <li>Randomly choose a X509 certificate from the endpoint X509 certificates, contained in 338 * {@code certificateFile}, and validate it against the root certificate pre-installed 339 * in the OS and chosen by {@code rootCertificateAlias}. 340 * <li>Store the chosen X509 certificate and the serial in local database for later use. 341 * </ol> 342 * 343 * @param rootCertificateAlias the alias of a root certificate pre-installed in the OS 344 * @param certificateFile the binary content of the XML file containing a list of recovery 345 * service X509 certificates, and other metadata including the serial number 346 * @param signatureFile the binary content of the XML file containing the public-key signature 347 * of the entire certificate file, and a signer's X509 certificate 348 * @throws CertificateException if the given certificate files cannot be parsed or validated 349 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 350 * service. 351 */ 352 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 353 public void initRecoveryService( 354 @NonNull String rootCertificateAlias, @NonNull byte[] certificateFile, 355 @NonNull byte[] signatureFile) 356 throws CertificateException, InternalRecoveryServiceException { 357 try { 358 mBinder.initRecoveryServiceWithSigFile( 359 rootCertificateAlias, certificateFile, signatureFile); 360 } catch (RemoteException e) { 361 throw e.rethrowFromSystemServer(); 362 } catch (ServiceSpecificException e) { 363 if (e.errorCode == ERROR_BAD_CERTIFICATE_FORMAT 364 || e.errorCode == ERROR_INVALID_CERTIFICATE) { 365 throw new CertificateException("Invalid certificate for recovery service", e); 366 } 367 if (e.errorCode == ERROR_DOWNGRADE_CERTIFICATE) { 368 throw new CertificateException( 369 "Downgrading certificate serial version isn't supported.", e); 370 } 371 throw wrapUnexpectedServiceSpecificException(e); 372 } 373 } 374 375 /** 376 * @deprecated Use {@link #getKeyChainSnapshot()} 377 * @removed 378 */ 379 @Deprecated 380 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 381 public @Nullable KeyChainSnapshot getRecoveryData() throws InternalRecoveryServiceException { 382 return getKeyChainSnapshot(); 383 } 384 385 /** 386 * Returns data necessary to store all recoverable keys. Key material is 387 * encrypted with user secret and recovery public key. 388 * 389 * @return Data necessary to recover keystore or {@code null} if snapshot is not available. 390 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 391 * service. 392 */ 393 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 394 public @Nullable KeyChainSnapshot getKeyChainSnapshot() 395 throws InternalRecoveryServiceException { 396 try { 397 return mBinder.getKeyChainSnapshot(); 398 } catch (RemoteException e) { 399 throw e.rethrowFromSystemServer(); 400 } catch (ServiceSpecificException e) { 401 if (e.errorCode == ERROR_NO_SNAPSHOT_PENDING) { 402 return null; 403 } 404 throw wrapUnexpectedServiceSpecificException(e); 405 } 406 } 407 408 /** 409 * Sets a listener which notifies recovery agent that new recovery snapshot is available. {@link 410 * #getKeyChainSnapshot} can be used to get the snapshot. Note that every recovery agent can 411 * have at most one registered listener at any time. 412 * 413 * @param intent triggered when new snapshot is available. Unregisters listener if the value is 414 * {@code null}. 415 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 416 * service. 417 */ 418 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 419 public void setSnapshotCreatedPendingIntent(@Nullable PendingIntent intent) 420 throws InternalRecoveryServiceException { 421 try { 422 mBinder.setSnapshotCreatedPendingIntent(intent); 423 } catch (RemoteException e) { 424 throw e.rethrowFromSystemServer(); 425 } catch (ServiceSpecificException e) { 426 throw wrapUnexpectedServiceSpecificException(e); 427 } 428 } 429 430 /** 431 * Server parameters used to generate new recovery key blobs. This value will be included in 432 * {@code KeyChainSnapshot.getEncryptedRecoveryKeyBlob()}. The same value must be included 433 * in vaultParams {@link RecoverySession#start(CertPath, byte[], byte[], List)}. 434 * 435 * @param serverParams included in recovery key blob. 436 * @see #getKeyChainSnapshot 437 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 438 * service. 439 */ 440 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 441 public void setServerParams(@NonNull byte[] serverParams) 442 throws InternalRecoveryServiceException { 443 try { 444 mBinder.setServerParams(serverParams); 445 } catch (RemoteException e) { 446 throw e.rethrowFromSystemServer(); 447 } catch (ServiceSpecificException e) { 448 throw wrapUnexpectedServiceSpecificException(e); 449 } 450 } 451 452 /** 453 * @deprecated Use {@link #getAliases()}. 454 * @removed 455 */ 456 @Deprecated 457 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 458 public List<String> getAliases(@Nullable String packageName) 459 throws InternalRecoveryServiceException { 460 return getAliases(); 461 } 462 463 /** 464 * Returns a list of aliases of keys belonging to the application. 465 */ 466 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 467 public @NonNull List<String> getAliases() throws InternalRecoveryServiceException { 468 try { 469 Map<String, Integer> allStatuses = mBinder.getRecoveryStatus(); 470 return new ArrayList<>(allStatuses.keySet()); 471 } catch (RemoteException e) { 472 throw e.rethrowFromSystemServer(); 473 } catch (ServiceSpecificException e) { 474 throw wrapUnexpectedServiceSpecificException(e); 475 } 476 } 477 478 /** 479 * @deprecated Use {@link #setRecoveryStatus(String, int)} 480 * @removed 481 */ 482 @Deprecated 483 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 484 public void setRecoveryStatus( 485 @NonNull String packageName, String alias, int status) 486 throws NameNotFoundException, InternalRecoveryServiceException { 487 setRecoveryStatus(alias, status); 488 } 489 490 /** 491 * Sets the recovery status for given key. It is used to notify the keystore that the key was 492 * successfully stored on the server or that there was an error. An application can check this 493 * value using {@link #getRecoveryStatus(String, String)}. 494 * 495 * @param alias The alias of the key whose status to set. 496 * @param status The status of the key. One of {@link #RECOVERY_STATUS_SYNCED}, 497 * {@link #RECOVERY_STATUS_SYNC_IN_PROGRESS} or {@link #RECOVERY_STATUS_PERMANENT_FAILURE}. 498 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 499 * service. 500 */ 501 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 502 public void setRecoveryStatus(@NonNull String alias, int status) 503 throws InternalRecoveryServiceException { 504 try { 505 mBinder.setRecoveryStatus(alias, status); 506 } catch (RemoteException e) { 507 throw e.rethrowFromSystemServer(); 508 } catch (ServiceSpecificException e) { 509 throw wrapUnexpectedServiceSpecificException(e); 510 } 511 } 512 513 /** 514 * @deprecated Use {@link #getRecoveryStatus(String)}. 515 * @removed 516 */ 517 @Deprecated 518 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 519 public int getRecoveryStatus(String packageName, String alias) 520 throws InternalRecoveryServiceException { 521 return getRecoveryStatus(alias); 522 } 523 524 /** 525 * Returns the recovery status for the key with the given {@code alias}. 526 * 527 * <ul> 528 * <li>{@link #RECOVERY_STATUS_SYNCED} 529 * <li>{@link #RECOVERY_STATUS_SYNC_IN_PROGRESS} 530 * <li>{@link #RECOVERY_STATUS_PERMANENT_FAILURE} 531 * </ul> 532 * 533 * @see #setRecoveryStatus(String, int) 534 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 535 * service. 536 */ 537 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 538 public int getRecoveryStatus(@NonNull String alias) throws InternalRecoveryServiceException { 539 try { 540 Map<String, Integer> allStatuses = mBinder.getRecoveryStatus(); 541 Integer status = allStatuses.get(alias); 542 if (status == null) { 543 return RecoveryController.RECOVERY_STATUS_PERMANENT_FAILURE; 544 } else { 545 return status; 546 } 547 } catch (RemoteException e) { 548 throw e.rethrowFromSystemServer(); 549 } catch (ServiceSpecificException e) { 550 throw wrapUnexpectedServiceSpecificException(e); 551 } 552 } 553 554 /** 555 * Specifies a set of secret types used for end-to-end keystore encryption. Knowing all of them 556 * is necessary to recover data. 557 * 558 * @param secretTypes {@link KeyChainProtectionParams#TYPE_LOCKSCREEN} 559 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 560 * service. 561 */ 562 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 563 public void setRecoverySecretTypes( 564 @NonNull @KeyChainProtectionParams.UserSecretType int[] secretTypes) 565 throws InternalRecoveryServiceException { 566 try { 567 mBinder.setRecoverySecretTypes(secretTypes); 568 } catch (RemoteException e) { 569 throw e.rethrowFromSystemServer(); 570 } catch (ServiceSpecificException e) { 571 throw wrapUnexpectedServiceSpecificException(e); 572 } 573 } 574 575 /** 576 * Defines a set of secret types used for end-to-end keystore encryption. Knowing all of them is 577 * necessary to generate KeyChainSnapshot. 578 * 579 * @return list of recovery secret types 580 * @see KeyChainSnapshot 581 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 582 * service. 583 */ 584 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 585 public @NonNull @KeyChainProtectionParams.UserSecretType int[] getRecoverySecretTypes() 586 throws InternalRecoveryServiceException { 587 try { 588 return mBinder.getRecoverySecretTypes(); 589 } catch (RemoteException e) { 590 throw e.rethrowFromSystemServer(); 591 } catch (ServiceSpecificException e) { 592 throw wrapUnexpectedServiceSpecificException(e); 593 } 594 } 595 596 /** 597 * Deprecated. 598 * Generates a AES256/GCM/NoPADDING key called {@code alias} and loads it into the recoverable 599 * key store. Returns the raw material of the key. 600 * 601 * @param alias The key alias. 602 * @param account The account associated with the key 603 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 604 * service. 605 * @throws LockScreenRequiredException if the user has not set a lock screen. This is required 606 * to generate recoverable keys, as the snapshots are encrypted using a key derived from the 607 * lock screen. 608 * @deprecated Use {@link #generateKey(String)} 609 * @removed 610 */ 611 @Deprecated 612 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 613 public byte[] generateAndStoreKey(@NonNull String alias, byte[] account) 614 throws InternalRecoveryServiceException, LockScreenRequiredException { 615 throw new UnsupportedOperationException("Operation is not supported, use generateKey"); 616 } 617 618 /** 619 * @deprecated Use {@link #generateKey(String)}. 620 * @removed 621 */ 622 @Deprecated 623 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 624 public Key generateKey(@NonNull String alias, byte[] account) 625 throws InternalRecoveryServiceException, LockScreenRequiredException { 626 return generateKey(alias); 627 } 628 629 /** 630 * Generates a recoverable key with the given {@code alias}. 631 * 632 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 633 * service. 634 * @throws LockScreenRequiredException if the user does not have a lock screen set. A lock 635 * screen is required to generate recoverable keys. 636 */ 637 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 638 public @NonNull Key generateKey(@NonNull String alias) throws InternalRecoveryServiceException, 639 LockScreenRequiredException { 640 try { 641 String grantAlias = mBinder.generateKey(alias); 642 if (grantAlias == null) { 643 throw new InternalRecoveryServiceException("null grant alias"); 644 } 645 return getKeyFromGrant(grantAlias); 646 } catch (RemoteException e) { 647 throw e.rethrowFromSystemServer(); 648 } catch (UnrecoverableKeyException e) { 649 throw new InternalRecoveryServiceException("Failed to get key from keystore", e); 650 } catch (ServiceSpecificException e) { 651 if (e.errorCode == ERROR_INSECURE_USER) { 652 throw new LockScreenRequiredException(e.getMessage()); 653 } 654 throw wrapUnexpectedServiceSpecificException(e); 655 } 656 } 657 658 /** 659 * Imports a 256-bit recoverable AES key with the given {@code alias} and the raw bytes {@code 660 * keyBytes}. 661 * 662 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 663 * service. 664 * @throws LockScreenRequiredException if the user does not have a lock screen set. A lock 665 * screen is required to generate recoverable keys. 666 * 667 */ 668 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 669 public @NonNull Key importKey(@NonNull String alias, @NonNull byte[] keyBytes) 670 throws InternalRecoveryServiceException, LockScreenRequiredException { 671 try { 672 String grantAlias = mBinder.importKey(alias, keyBytes); 673 if (grantAlias == null) { 674 throw new InternalRecoveryServiceException("Null grant alias"); 675 } 676 return getKeyFromGrant(grantAlias); 677 } catch (RemoteException e) { 678 throw e.rethrowFromSystemServer(); 679 } catch (UnrecoverableKeyException e) { 680 throw new InternalRecoveryServiceException("Failed to get key from keystore", e); 681 } catch (ServiceSpecificException e) { 682 if (e.errorCode == ERROR_INSECURE_USER) { 683 throw new LockScreenRequiredException(e.getMessage()); 684 } 685 throw wrapUnexpectedServiceSpecificException(e); 686 } 687 } 688 689 /** 690 * Gets a key called {@code alias} from the recoverable key store. 691 * 692 * @param alias The key alias. 693 * @return The key. 694 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 695 * service. 696 * @throws UnrecoverableKeyException if key is permanently invalidated or not found. 697 */ 698 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 699 public @Nullable Key getKey(@NonNull String alias) 700 throws InternalRecoveryServiceException, UnrecoverableKeyException { 701 try { 702 String grantAlias = mBinder.getKey(alias); 703 if (grantAlias == null || "".equals(grantAlias)) { 704 return null; 705 } 706 return getKeyFromGrant(grantAlias); 707 } catch (RemoteException e) { 708 throw e.rethrowFromSystemServer(); 709 } catch (ServiceSpecificException e) { 710 throw wrapUnexpectedServiceSpecificException(e); 711 } 712 } 713 714 /** 715 * Returns the key with the given {@code grantAlias}. 716 */ 717 @NonNull Key getKeyFromGrant(@NonNull String grantAlias) throws UnrecoverableKeyException { 718 return AndroidKeyStoreProvider.loadAndroidKeyStoreKeyFromKeystore( 719 mKeyStore, 720 grantAlias, 721 KeyStore.UID_SELF); 722 } 723 724 /** 725 * Removes a key called {@code alias} from the recoverable key store. 726 * 727 * @param alias The key alias. 728 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 729 * service. 730 */ 731 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 732 public void removeKey(@NonNull String alias) throws InternalRecoveryServiceException { 733 try { 734 mBinder.removeKey(alias); 735 } catch (RemoteException e) { 736 throw e.rethrowFromSystemServer(); 737 } catch (ServiceSpecificException e) { 738 throw wrapUnexpectedServiceSpecificException(e); 739 } 740 } 741 742 /** 743 * Returns a new {@link RecoverySession}. 744 * 745 * <p>A recovery session is required to restore keys from a remote store. 746 */ 747 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 748 public @NonNull RecoverySession createRecoverySession() { 749 return RecoverySession.newInstance(this); 750 } 751 752 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 753 public @NonNull Map<String, X509Certificate> getRootCertificates() { 754 return TrustedRootCertificates.getRootCertificates(); 755 } 756 757 InternalRecoveryServiceException wrapUnexpectedServiceSpecificException( 758 ServiceSpecificException e) { 759 if (e.errorCode == ERROR_SERVICE_INTERNAL_ERROR) { 760 return new InternalRecoveryServiceException(e.getMessage()); 761 } 762 763 // Should never happen. If it does, it's a bug, and we need to update how the method that 764 // called this throws its exceptions. 765 return new InternalRecoveryServiceException("Unexpected error code for method: " 766 + e.errorCode, e); 767 } 768} 769