RecoveryController.java revision b95c90ce2d10a93c680b2ddbdf7ad61feb3abf5a
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 */ 306 @Deprecated 307 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 308 public void initRecoveryService( 309 @NonNull String rootCertificateAlias, @NonNull byte[] signedPublicKeyList) 310 throws CertificateException, InternalRecoveryServiceException { 311 try { 312 mBinder.initRecoveryService(rootCertificateAlias, signedPublicKeyList); 313 } catch (RemoteException e) { 314 throw e.rethrowFromSystemServer(); 315 } catch (ServiceSpecificException e) { 316 if (e.errorCode == ERROR_BAD_CERTIFICATE_FORMAT 317 || e.errorCode == ERROR_INVALID_CERTIFICATE) { 318 throw new CertificateException("Invalid certificate for recovery service", e); 319 } 320 throw wrapUnexpectedServiceSpecificException(e); 321 } 322 } 323 324 /** 325 * Initializes the recovery service for the calling application. The detailed steps should be: 326 * <ol> 327 * <li>Parse {@code signatureFile} to get relevant information. 328 * <li>Validate the signer's X509 certificate, contained in {@code signatureFile}, against 329 * the root certificate pre-installed in the OS and chosen by {@code 330 * rootCertificateAlias}. 331 * <li>Verify the public-key signature, contained in {@code signatureFile}, and verify it 332 * against the entire {@code certificateFile}. 333 * <li>Parse {@code certificateFile} to get relevant information. 334 * <li>Check the serial number, contained in {@code certificateFile}, and skip the following 335 * steps if the serial number is not larger than the one previously stored. 336 * <li>Randomly choose a X509 certificate from the endpoint X509 certificates, contained in 337 * {@code certificateFile}, and validate it against the root certificate pre-installed 338 * in the OS and chosen by {@code rootCertificateAlias}. 339 * <li>Store the chosen X509 certificate and the serial in local database for later use. 340 * </ol> 341 * 342 * @param rootCertificateAlias the alias of a root certificate pre-installed in the OS 343 * @param certificateFile the binary content of the XML file containing a list of recovery 344 * service X509 certificates, and other metadata including the serial number 345 * @param signatureFile the binary content of the XML file containing the public-key signature 346 * of the entire certificate file, and a signer's X509 certificate 347 * @throws CertificateException if the given certificate files cannot be parsed or validated 348 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 349 * service. 350 */ 351 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 352 public void initRecoveryService( 353 @NonNull String rootCertificateAlias, @NonNull byte[] certificateFile, 354 @NonNull byte[] signatureFile) 355 throws CertificateException, InternalRecoveryServiceException { 356 try { 357 mBinder.initRecoveryServiceWithSigFile( 358 rootCertificateAlias, certificateFile, signatureFile); 359 } catch (RemoteException e) { 360 throw e.rethrowFromSystemServer(); 361 } catch (ServiceSpecificException e) { 362 if (e.errorCode == ERROR_BAD_CERTIFICATE_FORMAT 363 || e.errorCode == ERROR_INVALID_CERTIFICATE) { 364 throw new CertificateException("Invalid certificate for recovery service", e); 365 } 366 if (e.errorCode == ERROR_DOWNGRADE_CERTIFICATE) { 367 throw new CertificateException( 368 "Downgrading certificate serial version isn't supported.", e); 369 } 370 throw wrapUnexpectedServiceSpecificException(e); 371 } 372 } 373 374 /** 375 * @deprecated Use {@link #getKeyChainSnapshot()} 376 */ 377 @Deprecated 378 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 379 public @Nullable KeyChainSnapshot getRecoveryData() throws InternalRecoveryServiceException { 380 return getKeyChainSnapshot(); 381 } 382 383 /** 384 * Returns data necessary to store all recoverable keys. Key material is 385 * encrypted with user secret and recovery public key. 386 * 387 * @return Data necessary to recover keystore or {@code null} if snapshot is not available. 388 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 389 * service. 390 */ 391 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 392 public @Nullable KeyChainSnapshot getKeyChainSnapshot() 393 throws InternalRecoveryServiceException { 394 try { 395 return mBinder.getKeyChainSnapshot(); 396 } catch (RemoteException e) { 397 throw e.rethrowFromSystemServer(); 398 } catch (ServiceSpecificException e) { 399 if (e.errorCode == ERROR_NO_SNAPSHOT_PENDING) { 400 return null; 401 } 402 throw wrapUnexpectedServiceSpecificException(e); 403 } 404 } 405 406 /** 407 * Sets a listener which notifies recovery agent that new recovery snapshot is available. {@link 408 * #getKeyChainSnapshot} can be used to get the snapshot. Note that every recovery agent can 409 * have at most one registered listener at any time. 410 * 411 * @param intent triggered when new snapshot is available. Unregisters listener if the value is 412 * {@code null}. 413 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 414 * service. 415 */ 416 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 417 public void setSnapshotCreatedPendingIntent(@Nullable PendingIntent intent) 418 throws InternalRecoveryServiceException { 419 try { 420 mBinder.setSnapshotCreatedPendingIntent(intent); 421 } catch (RemoteException e) { 422 throw e.rethrowFromSystemServer(); 423 } catch (ServiceSpecificException e) { 424 throw wrapUnexpectedServiceSpecificException(e); 425 } 426 } 427 428 /** 429 * Server parameters used to generate new recovery key blobs. This value will be included in 430 * {@code KeyChainSnapshot.getEncryptedRecoveryKeyBlob()}. The same value must be included 431 * in vaultParams {@link RecoverySession#start(CertPath, byte[], byte[], List)}. 432 * 433 * @param serverParams included in recovery key blob. 434 * @see #getKeyChainSnapshot 435 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 436 * service. 437 */ 438 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 439 public void setServerParams(@NonNull byte[] serverParams) 440 throws InternalRecoveryServiceException { 441 try { 442 mBinder.setServerParams(serverParams); 443 } catch (RemoteException e) { 444 throw e.rethrowFromSystemServer(); 445 } catch (ServiceSpecificException e) { 446 throw wrapUnexpectedServiceSpecificException(e); 447 } 448 } 449 450 /** 451 * @deprecated Use {@link #getAliases()}. 452 */ 453 @Deprecated 454 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 455 public List<String> getAliases(@Nullable String packageName) 456 throws InternalRecoveryServiceException { 457 return getAliases(); 458 } 459 460 /** 461 * Returns a list of aliases of keys belonging to the application. 462 */ 463 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 464 public @NonNull List<String> getAliases() throws InternalRecoveryServiceException { 465 try { 466 Map<String, Integer> allStatuses = mBinder.getRecoveryStatus(); 467 return new ArrayList<>(allStatuses.keySet()); 468 } catch (RemoteException e) { 469 throw e.rethrowFromSystemServer(); 470 } catch (ServiceSpecificException e) { 471 throw wrapUnexpectedServiceSpecificException(e); 472 } 473 } 474 475 /** 476 * @deprecated Use {@link #setRecoveryStatus(String, int)} 477 */ 478 @Deprecated 479 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 480 public void setRecoveryStatus( 481 @NonNull String packageName, String alias, int status) 482 throws NameNotFoundException, InternalRecoveryServiceException { 483 setRecoveryStatus(alias, status); 484 } 485 486 /** 487 * Sets the recovery status for given key. It is used to notify the keystore that the key was 488 * successfully stored on the server or that there was an error. An application can check this 489 * value using {@link #getRecoveryStatus(String, String)}. 490 * 491 * @param alias The alias of the key whose status to set. 492 * @param status The status of the key. One of {@link #RECOVERY_STATUS_SYNCED}, 493 * {@link #RECOVERY_STATUS_SYNC_IN_PROGRESS} or {@link #RECOVERY_STATUS_PERMANENT_FAILURE}. 494 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 495 * service. 496 */ 497 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 498 public void setRecoveryStatus(@NonNull String alias, int status) 499 throws InternalRecoveryServiceException { 500 try { 501 mBinder.setRecoveryStatus(alias, status); 502 } catch (RemoteException e) { 503 throw e.rethrowFromSystemServer(); 504 } catch (ServiceSpecificException e) { 505 throw wrapUnexpectedServiceSpecificException(e); 506 } 507 } 508 509 /** 510 * @deprecated Use {@link #getRecoveryStatus(String)}. 511 */ 512 @Deprecated 513 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 514 public int getRecoveryStatus(String packageName, String alias) 515 throws InternalRecoveryServiceException { 516 return getRecoveryStatus(alias); 517 } 518 519 /** 520 * Returns the recovery status for the key with the given {@code alias}. 521 * 522 * <ul> 523 * <li>{@link #RECOVERY_STATUS_SYNCED} 524 * <li>{@link #RECOVERY_STATUS_SYNC_IN_PROGRESS} 525 * <li>{@link #RECOVERY_STATUS_PERMANENT_FAILURE} 526 * </ul> 527 * 528 * @see #setRecoveryStatus(String, int) 529 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 530 * service. 531 */ 532 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 533 public int getRecoveryStatus(@NonNull String alias) throws InternalRecoveryServiceException { 534 try { 535 Map<String, Integer> allStatuses = mBinder.getRecoveryStatus(); 536 Integer status = allStatuses.get(alias); 537 if (status == null) { 538 return RecoveryController.RECOVERY_STATUS_PERMANENT_FAILURE; 539 } else { 540 return status; 541 } 542 } catch (RemoteException e) { 543 throw e.rethrowFromSystemServer(); 544 } catch (ServiceSpecificException e) { 545 throw wrapUnexpectedServiceSpecificException(e); 546 } 547 } 548 549 /** 550 * Specifies a set of secret types used for end-to-end keystore encryption. Knowing all of them 551 * is necessary to recover data. 552 * 553 * @param secretTypes {@link KeyChainProtectionParams#TYPE_LOCKSCREEN} 554 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 555 * service. 556 */ 557 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 558 public void setRecoverySecretTypes( 559 @NonNull @KeyChainProtectionParams.UserSecretType int[] secretTypes) 560 throws InternalRecoveryServiceException { 561 try { 562 mBinder.setRecoverySecretTypes(secretTypes); 563 } catch (RemoteException e) { 564 throw e.rethrowFromSystemServer(); 565 } catch (ServiceSpecificException e) { 566 throw wrapUnexpectedServiceSpecificException(e); 567 } 568 } 569 570 /** 571 * Defines a set of secret types used for end-to-end keystore encryption. Knowing all of them is 572 * necessary to generate KeyChainSnapshot. 573 * 574 * @return list of recovery secret types 575 * @see KeyChainSnapshot 576 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 577 * service. 578 */ 579 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 580 public @NonNull @KeyChainProtectionParams.UserSecretType int[] getRecoverySecretTypes() 581 throws InternalRecoveryServiceException { 582 try { 583 return mBinder.getRecoverySecretTypes(); 584 } catch (RemoteException e) { 585 throw e.rethrowFromSystemServer(); 586 } catch (ServiceSpecificException e) { 587 throw wrapUnexpectedServiceSpecificException(e); 588 } 589 } 590 591 /** 592 * Deprecated. 593 * Generates a AES256/GCM/NoPADDING key called {@code alias} and loads it into the recoverable 594 * key store. Returns the raw material of the key. 595 * 596 * @param alias The key alias. 597 * @param account The account associated with the key 598 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 599 * service. 600 * @throws LockScreenRequiredException if the user has not set a lock screen. This is required 601 * to generate recoverable keys, as the snapshots are encrypted using a key derived from the 602 * lock screen. 603 */ 604 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 605 public byte[] generateAndStoreKey(@NonNull String alias, byte[] account) 606 throws InternalRecoveryServiceException, LockScreenRequiredException { 607 throw new UnsupportedOperationException("Operation is not supported, use generateKey"); 608 } 609 610 /** 611 * @deprecated Use {@link #generateKey(String)}. 612 */ 613 @Deprecated 614 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 615 public Key generateKey(@NonNull String alias, byte[] account) 616 throws InternalRecoveryServiceException, LockScreenRequiredException { 617 return generateKey(alias); 618 } 619 620 /** 621 * Generates a recoverable key with the given {@code alias}. 622 * 623 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 624 * service. 625 * @throws LockScreenRequiredException if the user does not have a lock screen set. A lock 626 * screen is required to generate recoverable keys. 627 */ 628 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 629 public @NonNull Key generateKey(@NonNull String alias) throws InternalRecoveryServiceException, 630 LockScreenRequiredException { 631 try { 632 String grantAlias = mBinder.generateKey(alias); 633 if (grantAlias == null) { 634 throw new InternalRecoveryServiceException("null grant alias"); 635 } 636 return getKeyFromGrant(grantAlias); 637 } catch (RemoteException e) { 638 throw e.rethrowFromSystemServer(); 639 } catch (UnrecoverableKeyException e) { 640 throw new InternalRecoveryServiceException("Failed to get key from keystore", e); 641 } catch (ServiceSpecificException e) { 642 if (e.errorCode == ERROR_INSECURE_USER) { 643 throw new LockScreenRequiredException(e.getMessage()); 644 } 645 throw wrapUnexpectedServiceSpecificException(e); 646 } 647 } 648 649 /** 650 * Imports a 256-bit recoverable AES key with the given {@code alias} and the raw bytes {@code 651 * keyBytes}. 652 * 653 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 654 * service. 655 * @throws LockScreenRequiredException if the user does not have a lock screen set. A lock 656 * screen is required to generate recoverable keys. 657 * 658 */ 659 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 660 public @NonNull Key importKey(@NonNull String alias, @NonNull byte[] keyBytes) 661 throws InternalRecoveryServiceException, LockScreenRequiredException { 662 try { 663 String grantAlias = mBinder.importKey(alias, keyBytes); 664 if (grantAlias == null) { 665 throw new InternalRecoveryServiceException("Null grant alias"); 666 } 667 return getKeyFromGrant(grantAlias); 668 } catch (RemoteException e) { 669 throw e.rethrowFromSystemServer(); 670 } catch (UnrecoverableKeyException e) { 671 throw new InternalRecoveryServiceException("Failed to get key from keystore", e); 672 } catch (ServiceSpecificException e) { 673 if (e.errorCode == ERROR_INSECURE_USER) { 674 throw new LockScreenRequiredException(e.getMessage()); 675 } 676 throw wrapUnexpectedServiceSpecificException(e); 677 } 678 } 679 680 /** 681 * Gets a key called {@code alias} from the recoverable key store. 682 * 683 * @param alias The key alias. 684 * @return The key. 685 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 686 * service. 687 * @throws UnrecoverableKeyException if key is permanently invalidated or not found. 688 */ 689 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 690 public @Nullable Key getKey(@NonNull String alias) 691 throws InternalRecoveryServiceException, UnrecoverableKeyException { 692 try { 693 String grantAlias = mBinder.getKey(alias); 694 if (grantAlias == null || "".equals(grantAlias)) { 695 return null; 696 } 697 return getKeyFromGrant(grantAlias); 698 } catch (RemoteException e) { 699 throw e.rethrowFromSystemServer(); 700 } catch (ServiceSpecificException e) { 701 throw wrapUnexpectedServiceSpecificException(e); 702 } 703 } 704 705 /** 706 * Returns the key with the given {@code grantAlias}. 707 */ 708 @NonNull Key getKeyFromGrant(@NonNull String grantAlias) throws UnrecoverableKeyException { 709 return AndroidKeyStoreProvider.loadAndroidKeyStoreKeyFromKeystore( 710 mKeyStore, 711 grantAlias, 712 KeyStore.UID_SELF); 713 } 714 715 /** 716 * Removes a key called {@code alias} from the recoverable key store. 717 * 718 * @param alias The key alias. 719 * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery 720 * service. 721 */ 722 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 723 public void removeKey(@NonNull String alias) throws InternalRecoveryServiceException { 724 try { 725 mBinder.removeKey(alias); 726 } catch (RemoteException e) { 727 throw e.rethrowFromSystemServer(); 728 } catch (ServiceSpecificException e) { 729 throw wrapUnexpectedServiceSpecificException(e); 730 } 731 } 732 733 /** 734 * Returns a new {@link RecoverySession}. 735 * 736 * <p>A recovery session is required to restore keys from a remote store. 737 */ 738 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 739 public @NonNull RecoverySession createRecoverySession() { 740 return RecoverySession.newInstance(this); 741 } 742 743 @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) 744 public @NonNull Map<String, X509Certificate> getRootCertificates() { 745 return TrustedRootCertificates.getRootCertificates(); 746 } 747 748 InternalRecoveryServiceException wrapUnexpectedServiceSpecificException( 749 ServiceSpecificException e) { 750 if (e.errorCode == ERROR_SERVICE_INTERNAL_ERROR) { 751 return new InternalRecoveryServiceException(e.getMessage()); 752 } 753 754 // Should never happen. If it does, it's a bug, and we need to update how the method that 755 // called this throws its exceptions. 756 return new InternalRecoveryServiceException("Unexpected error code for method: " 757 + e.errorCode, e); 758 } 759} 760