| /* |
| * Copyright (C) 2017 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package android.security.keystore.recovery; |
| |
| import android.annotation.NonNull; |
| import android.annotation.Nullable; |
| import android.annotation.RequiresPermission; |
| import android.annotation.SystemApi; |
| import android.app.KeyguardManager; |
| import android.app.PendingIntent; |
| import android.content.Context; |
| import android.os.RemoteException; |
| import android.os.ServiceManager; |
| import android.os.ServiceSpecificException; |
| import android.security.KeyStore; |
| import android.security.keystore.AndroidKeyStoreProvider; |
| import android.security.keystore.KeyPermanentlyInvalidatedException; |
| |
| import com.android.internal.widget.ILockSettings; |
| |
| import java.security.Key; |
| import java.security.UnrecoverableKeyException; |
| import java.security.cert.CertPath; |
| import java.security.cert.CertificateException; |
| import java.security.cert.X509Certificate; |
| import java.util.ArrayList; |
| import java.util.List; |
| import java.util.Map; |
| |
| /** |
| * Backs up cryptographic keys to remote secure hardware, encrypted with the user's lock screen. |
| * |
| * <p>A system app with the {@code android.permission.RECOVER_KEYSTORE} permission may generate or |
| * import recoverable keys using this class. To generate a key, the app must call |
| * {@link #generateKey(String)} with the desired alias for the key. This returns an AndroidKeyStore |
| * reference to a 256-bit {@link javax.crypto.SecretKey}, which can be used for AES/GCM/NoPadding. |
| * In order to get the same key again at a later time, the app can call {@link #getKey(String)} with |
| * the same alias. If a key is generated in this way the key's raw material is never directly |
| * exposed to the calling app. The system app may also import key material using |
| * {@link #importKey(String, byte[])}. The app may only generate and import keys for its own |
| * {@code uid}. |
| * |
| * <p>The same system app must also register a Recovery Agent to manage syncing recoverable keys to |
| * remote secure hardware. The Recovery Agent is a service that registers itself with the controller |
| * as follows: |
| * |
| * <ul> |
| * <li>Invokes {@link #initRecoveryService(String, byte[], byte[])} |
| * <ul> |
| * <li>The first argument is the alias of the root certificate used to verify trusted |
| * hardware modules. Each trusted hardware module must have a public key signed with this |
| * root of trust. Roots of trust must be shipped with the framework. The app can list all |
| * valid roots of trust by calling {@link #getRootCertificates()}. |
| * <li>The second argument is the UTF-8 bytes of the XML listing file. It lists the X509 |
| * certificates containing the public keys of all available remote trusted hardware modules. |
| * Each of the X509 certificates can be validated against the chosen root of trust. |
| * <li>The third argument is the UTF-8 bytes of the XML signing file. The file contains a |
| * signature of the XML listing file. The signature can be validated against the chosen root |
| * of trust. |
| * </ul> |
| * <p>This will cause the controller to choose a random public key from the list. From then |
| * on the controller will attempt to sync the key chain with the trusted hardware module to whom |
| * that key belongs. |
| * <li>Invokes {@link #setServerParams(byte[])} with a byte string that identifies the device |
| * to a remote server. This server may act as the front-end to the trusted hardware modules. It |
| * is up to the Recovery Agent to decide how best to identify devices, but this could be, e.g., |
| * based on the <a href="https://developers.google.com/instance-id/">Instance ID</a> of the |
| * system app. |
| * <li>Invokes {@link #setRecoverySecretTypes(int[])} with a list of types of secret used to |
| * secure the recoverable key chain. For now only |
| * {@link KeyChainProtectionParams#TYPE_LOCKSCREEN} is supported. |
| * <li>Invokes {@link #setSnapshotCreatedPendingIntent(PendingIntent)} with a |
| * {@link PendingIntent} that is to be invoked whenever a new snapshot is created. Although the |
| * controller can create snapshots without the Recovery Agent registering this intent, it is a |
| * good idea to register the intent so that the Recovery Agent is able to sync this snapshot to |
| * the trusted hardware module as soon as it is available. |
| * </ul> |
| * |
| * <p>The trusted hardware module's public key MUST be generated on secure hardware with protections |
| * equivalent to those described in the |
| * <a href="https://developer.android.com/preview/features/security/ckv-whitepaper.html">Google |
| * Cloud Key Vault Service whitepaper</a>. The trusted hardware module itself must protect the key |
| * chain from brute-forcing using the methods also described in the whitepaper: i.e., it should |
| * limit the number of allowed attempts to enter the lock screen. If the number of attempts is |
| * exceeded the key material must no longer be recoverable. |
| * |
| * <p>A recoverable key chain snapshot is considered pending if any of the following conditions |
| * are met: |
| * |
| * <ul> |
| * <li>The system app mutates the key chain. i.e., generates, imports, or removes a key. |
| * <li>The user changes their lock screen. |
| * </ul> |
| * |
| * <p>Whenever the user unlocks their device, if a snapshot is pending, the Recovery Controller |
| * generates a new snapshot. It follows these steps to do so: |
| * |
| * <ul> |
| * <li>Generates a 256-bit AES key using {@link java.security.SecureRandom}. This is the |
| * Recovery Key. |
| * <li>Wraps the key material of all keys in the recoverable key chain with the Recovery Key. |
| * <li>Encrypts the Recovery Key with both the public key of the trusted hardware module and a |
| * symmetric key derived from the user's lock screen. |
| * </ul> |
| * |
| * <p>The controller then writes this snapshot to disk, and uses the {@link PendingIntent} that was |
| * set by the Recovery Agent during initialization to inform it that a new snapshot is available. |
| * The snapshot only contains keys for that Recovery Agent's {@code uid} - i.e., keys the agent's |
| * app itself generated. If multiple Recovery Agents exist on the device, each will be notified of |
| * their new snapshots, and each snapshots' keys will be only those belonging to the same |
| * {@code uid}. |
| * |
| * <p>The Recovery Agent retrieves its most recent snapshot by calling |
| * {@link #getKeyChainSnapshot()}. It syncs the snapshot to the remote server. The snapshot contains |
| * the public key used for encryption, which the server uses to forward the encrypted recovery key |
| * to the correct trusted hardware module. The snapshot also contains the server params, which are |
| * used to identify this device to the server. |
| * |
| * <p>The client uses the server params to identify a device whose key chain it wishes to restore. |
| * This may be on a different device to the device that originally synced the key chain. The client |
| * sends the server params identifying the previous device to the server. The server returns the |
| * X509 certificate identifying the trusted hardware module in which the encrypted Recovery Key is |
| * stored. It also returns some vault parameters identifying that particular Recovery Key to the |
| * trusted hardware module. And it also returns a vault challenge, which is used as part of the |
| * vault opening protocol to ensure the recovery claim is fresh. See the whitepaper for more |
| * details. |
| * |
| * <p>The key chain is recovered via a {@link RecoverySession}. A Recovery Agent creates one by |
| * invoking {@link #createRecoverySession()}. It then invokes |
| * {@link RecoverySession#start(String, CertPath, byte[], byte[], List)} with these arguments: |
| * |
| * <ul> |
| * <li>The alias of the root of trust used to verify the trusted hardware module. |
| * <li>The X509 certificate of the trusted hardware module. |
| * <li>The vault parameters used to identify the Recovery Key to the trusted hardware module. |
| * <li>The vault challenge, as issued by the trusted hardware module. |
| * <li>A list of secrets, corresponding to the secrets used to protect the key chain. At the |
| * moment this is a single {@link KeyChainProtectionParams} containing the lock screen of the |
| * device whose key chain is to be recovered. |
| * </ul> |
| * |
| * <p>This method returns a byte array containing the Recovery Claim, which can be issued to the |
| * remote trusted hardware module. It is encrypted with the trusted hardware module's public key |
| * (which has itself been certified with the root of trust). It also contains an ephemeral symmetric |
| * key generated for this recovery session, which the remote trusted hardware module uses to encrypt |
| * its responses. This is the Session Key. |
| * |
| * <p>If the lock screen provided is correct, the remote trusted hardware module decrypts one of the |
| * layers of lock-screen encryption from the Recovery Key. It then returns this key, encrypted with |
| * the Session Key to the Recovery Agent. As the Recovery Agent does not know the Session Key, it |
| * must then invoke {@link RecoverySession#recoverKeyChainSnapshot(byte[], List)} with the encrypted |
| * Recovery Key and the list of wrapped application keys. The controller then decrypts the layer of |
| * encryption provided by the Session Key, and uses the lock screen to decrypt the final layer of |
| * encryption. It then uses the Recovery Key to decrypt all of the wrapped application keys, and |
| * imports them into its own KeyStore. The Recovery Agent's app may then access these keys by |
| * calling {@link #getKey(String)}. Only this app's {@code uid} may access the keys that have been |
| * recovered. |
| * |
| * @hide |
| */ |
| @SystemApi |
| public class RecoveryController { |
| private static final String TAG = "RecoveryController"; |
| |
| /** Key has been successfully synced. */ |
| public static final int RECOVERY_STATUS_SYNCED = 0; |
| /** Waiting for recovery agent to sync the key. */ |
| public static final int RECOVERY_STATUS_SYNC_IN_PROGRESS = 1; |
| /** Key cannot be synced. */ |
| public static final int RECOVERY_STATUS_PERMANENT_FAILURE = 3; |
| |
| /** |
| * Failed because no snapshot is yet pending to be synced for the user. |
| * |
| * @hide |
| */ |
| public static final int ERROR_NO_SNAPSHOT_PENDING = 21; |
| |
| /** |
| * Failed due to an error internal to the recovery service. This is unexpected and indicates |
| * either a problem with the logic in the service, or a problem with a dependency of the |
| * service (such as AndroidKeyStore). |
| * |
| * @hide |
| */ |
| public static final int ERROR_SERVICE_INTERNAL_ERROR = 22; |
| |
| /** |
| * Failed because the user does not have a lock screen set. |
| * |
| * @hide |
| */ |
| public static final int ERROR_INSECURE_USER = 23; |
| |
| /** |
| * Error thrown when attempting to use a recovery session that has since been closed. |
| * |
| * @hide |
| */ |
| public static final int ERROR_SESSION_EXPIRED = 24; |
| |
| /** |
| * Failed because the format of the provided certificate is incorrect, e.g., cannot be decoded |
| * properly or misses necessary fields. |
| * |
| * <p>Note that this is different from {@link #ERROR_INVALID_CERTIFICATE}, which implies the |
| * certificate has a correct format but cannot be validated. |
| * |
| * @hide |
| */ |
| public static final int ERROR_BAD_CERTIFICATE_FORMAT = 25; |
| |
| /** |
| * Error thrown if decryption failed. This might be because the tag is wrong, the key is wrong, |
| * the data has become corrupted, the data has been tampered with, etc. |
| * |
| * @hide |
| */ |
| public static final int ERROR_DECRYPTION_FAILED = 26; |
| |
| /** |
| * Error thrown if the format of a given key is invalid. This might be because the key has a |
| * wrong length, invalid content, etc. |
| * |
| * @hide |
| */ |
| public static final int ERROR_INVALID_KEY_FORMAT = 27; |
| |
| /** |
| * Failed because the provided certificate cannot be validated, e.g., is expired or has invalid |
| * signatures. |
| * |
| * <p>Note that this is different from {@link #ERROR_BAD_CERTIFICATE_FORMAT}, which denotes |
| * incorrect certificate formats, e.g., due to wrong encoding or structure. |
| * |
| * @hide |
| */ |
| public static final int ERROR_INVALID_CERTIFICATE = 28; |
| |
| |
| /** |
| * Failed because the provided certificate contained serial version which is lower that the |
| * version device is already initialized with. It is not possible to downgrade serial version of |
| * the provided certificate. |
| * |
| * @hide |
| */ |
| public static final int ERROR_DOWNGRADE_CERTIFICATE = 29; |
| |
| private final ILockSettings mBinder; |
| private final KeyStore mKeyStore; |
| |
| private RecoveryController(ILockSettings binder, KeyStore keystore) { |
| mBinder = binder; |
| mKeyStore = keystore; |
| } |
| |
| /** |
| * Internal method used by {@code RecoverySession}. |
| * |
| * @hide |
| */ |
| ILockSettings getBinder() { |
| return mBinder; |
| } |
| |
| /** |
| * Gets a new instance of the class. |
| */ |
| @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) |
| @NonNull public static RecoveryController getInstance(@NonNull Context context) { |
| // lockSettings may be null. |
| ILockSettings lockSettings = |
| ILockSettings.Stub.asInterface(ServiceManager.getService("lock_settings")); |
| return new RecoveryController(lockSettings, KeyStore.getInstance()); |
| } |
| |
| /** |
| * Checks whether the recoverable key store is currently available. |
| * |
| * <p>If it returns true, the device must currently be using a screen lock that is supported for |
| * use with the recoverable key store, i.e. AOSP PIN, pattern or password. |
| */ |
| @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) |
| public static boolean isRecoverableKeyStoreEnabled(@NonNull Context context) { |
| KeyguardManager keyguardManager = context.getSystemService(KeyguardManager.class); |
| return keyguardManager != null && keyguardManager.isDeviceSecure(); |
| } |
| |
| /** |
| * Initializes the recovery service for the calling application. The detailed steps should be: |
| * <ol> |
| * <li>Parse {@code signatureFile} to get relevant information. |
| * <li>Validate the signer's X509 certificate, contained in {@code signatureFile}, against |
| * the root certificate pre-installed in the OS and chosen by {@code |
| * rootCertificateAlias}. |
| * <li>Verify the public-key signature, contained in {@code signatureFile}, and verify it |
| * against the entire {@code certificateFile}. |
| * <li>Parse {@code certificateFile} to get relevant information. |
| * <li>Check the serial number, contained in {@code certificateFile}, and skip the following |
| * steps if the serial number is not larger than the one previously stored. |
| * <li>Randomly choose a X509 certificate from the endpoint X509 certificates, contained in |
| * {@code certificateFile}, and validate it against the root certificate pre-installed |
| * in the OS and chosen by {@code rootCertificateAlias}. |
| * <li>Store the chosen X509 certificate and the serial in local database for later use. |
| * </ol> |
| * |
| * @param rootCertificateAlias the alias of a root certificate pre-installed in the OS |
| * @param certificateFile the binary content of the XML file containing a list of recovery |
| * service X509 certificates, and other metadata including the serial number |
| * @param signatureFile the binary content of the XML file containing the public-key signature |
| * of the entire certificate file, and a signer's X509 certificate |
| * @throws CertificateException if the given certificate files cannot be parsed or validated |
| * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery |
| * service. |
| */ |
| @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) |
| public void initRecoveryService( |
| @NonNull String rootCertificateAlias, @NonNull byte[] certificateFile, |
| @NonNull byte[] signatureFile) |
| throws CertificateException, InternalRecoveryServiceException { |
| try { |
| mBinder.initRecoveryServiceWithSigFile( |
| rootCertificateAlias, certificateFile, signatureFile); |
| } catch (RemoteException e) { |
| throw e.rethrowFromSystemServer(); |
| } catch (ServiceSpecificException e) { |
| if (e.errorCode == ERROR_BAD_CERTIFICATE_FORMAT |
| || e.errorCode == ERROR_INVALID_CERTIFICATE) { |
| throw new CertificateException("Invalid certificate for recovery service", e); |
| } |
| if (e.errorCode == ERROR_DOWNGRADE_CERTIFICATE) { |
| throw new CertificateException( |
| "Downgrading certificate serial version isn't supported.", e); |
| } |
| throw wrapUnexpectedServiceSpecificException(e); |
| } |
| } |
| |
| /** |
| * Returns data necessary to store all recoverable keys. Key material is |
| * encrypted with user secret and recovery public key. |
| * |
| * @return Data necessary to recover keystore or {@code null} if snapshot is not available. |
| * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery |
| * service. |
| */ |
| @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) |
| public @Nullable KeyChainSnapshot getKeyChainSnapshot() |
| throws InternalRecoveryServiceException { |
| try { |
| return mBinder.getKeyChainSnapshot(); |
| } catch (RemoteException e) { |
| throw e.rethrowFromSystemServer(); |
| } catch (ServiceSpecificException e) { |
| if (e.errorCode == ERROR_NO_SNAPSHOT_PENDING) { |
| return null; |
| } |
| throw wrapUnexpectedServiceSpecificException(e); |
| } |
| } |
| |
| /** |
| * Sets a listener which notifies recovery agent that new recovery snapshot is available. {@link |
| * #getKeyChainSnapshot} can be used to get the snapshot. Note that every recovery agent can |
| * have at most one registered listener at any time. |
| * |
| * @param intent triggered when new snapshot is available. Unregisters listener if the value is |
| * {@code null}. |
| * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery |
| * service. |
| */ |
| @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) |
| public void setSnapshotCreatedPendingIntent(@Nullable PendingIntent intent) |
| throws InternalRecoveryServiceException { |
| try { |
| mBinder.setSnapshotCreatedPendingIntent(intent); |
| } catch (RemoteException e) { |
| throw e.rethrowFromSystemServer(); |
| } catch (ServiceSpecificException e) { |
| throw wrapUnexpectedServiceSpecificException(e); |
| } |
| } |
| |
| /** |
| * Server parameters used to generate new recovery key blobs. This value will be included in |
| * {@code KeyChainSnapshot.getEncryptedRecoveryKeyBlob()}. The same value must be included |
| * in vaultParams {@link RecoverySession#start(CertPath, byte[], byte[], List)}. |
| * |
| * @param serverParams included in recovery key blob. |
| * @see #getKeyChainSnapshot |
| * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery |
| * service. |
| */ |
| @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) |
| public void setServerParams(@NonNull byte[] serverParams) |
| throws InternalRecoveryServiceException { |
| try { |
| mBinder.setServerParams(serverParams); |
| } catch (RemoteException e) { |
| throw e.rethrowFromSystemServer(); |
| } catch (ServiceSpecificException e) { |
| throw wrapUnexpectedServiceSpecificException(e); |
| } |
| } |
| |
| /** |
| * Returns a list of aliases of keys belonging to the application. |
| */ |
| @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) |
| public @NonNull List<String> getAliases() throws InternalRecoveryServiceException { |
| try { |
| Map<String, Integer> allStatuses = mBinder.getRecoveryStatus(); |
| return new ArrayList<>(allStatuses.keySet()); |
| } catch (RemoteException e) { |
| throw e.rethrowFromSystemServer(); |
| } catch (ServiceSpecificException e) { |
| throw wrapUnexpectedServiceSpecificException(e); |
| } |
| } |
| |
| /** |
| * Sets the recovery status for given key. It is used to notify the keystore that the key was |
| * successfully stored on the server or that there was an error. An application can check this |
| * value using {@link #getRecoveryStatus(String, String)}. |
| * |
| * @param alias The alias of the key whose status to set. |
| * @param status The status of the key. One of {@link #RECOVERY_STATUS_SYNCED}, |
| * {@link #RECOVERY_STATUS_SYNC_IN_PROGRESS} or {@link #RECOVERY_STATUS_PERMANENT_FAILURE}. |
| * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery |
| * service. |
| */ |
| @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) |
| public void setRecoveryStatus(@NonNull String alias, int status) |
| throws InternalRecoveryServiceException { |
| try { |
| mBinder.setRecoveryStatus(alias, status); |
| } catch (RemoteException e) { |
| throw e.rethrowFromSystemServer(); |
| } catch (ServiceSpecificException e) { |
| throw wrapUnexpectedServiceSpecificException(e); |
| } |
| } |
| |
| /** |
| * Returns the recovery status for the key with the given {@code alias}. |
| * |
| * <ul> |
| * <li>{@link #RECOVERY_STATUS_SYNCED} |
| * <li>{@link #RECOVERY_STATUS_SYNC_IN_PROGRESS} |
| * <li>{@link #RECOVERY_STATUS_PERMANENT_FAILURE} |
| * </ul> |
| * |
| * @see #setRecoveryStatus(String, int) |
| * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery |
| * service. |
| */ |
| @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) |
| public int getRecoveryStatus(@NonNull String alias) throws InternalRecoveryServiceException { |
| try { |
| Map<String, Integer> allStatuses = mBinder.getRecoveryStatus(); |
| Integer status = allStatuses.get(alias); |
| if (status == null) { |
| return RecoveryController.RECOVERY_STATUS_PERMANENT_FAILURE; |
| } else { |
| return status; |
| } |
| } catch (RemoteException e) { |
| throw e.rethrowFromSystemServer(); |
| } catch (ServiceSpecificException e) { |
| throw wrapUnexpectedServiceSpecificException(e); |
| } |
| } |
| |
| /** |
| * Specifies a set of secret types used for end-to-end keystore encryption. Knowing all of them |
| * is necessary to recover data. |
| * |
| * @param secretTypes {@link KeyChainProtectionParams#TYPE_LOCKSCREEN} |
| * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery |
| * service. |
| */ |
| @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) |
| public void setRecoverySecretTypes( |
| @NonNull @KeyChainProtectionParams.UserSecretType int[] secretTypes) |
| throws InternalRecoveryServiceException { |
| try { |
| mBinder.setRecoverySecretTypes(secretTypes); |
| } catch (RemoteException e) { |
| throw e.rethrowFromSystemServer(); |
| } catch (ServiceSpecificException e) { |
| throw wrapUnexpectedServiceSpecificException(e); |
| } |
| } |
| |
| /** |
| * Defines a set of secret types used for end-to-end keystore encryption. Knowing all of them is |
| * necessary to generate KeyChainSnapshot. |
| * |
| * @return list of recovery secret types |
| * @see KeyChainSnapshot |
| * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery |
| * service. |
| */ |
| @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) |
| public @NonNull @KeyChainProtectionParams.UserSecretType int[] getRecoverySecretTypes() |
| throws InternalRecoveryServiceException { |
| try { |
| return mBinder.getRecoverySecretTypes(); |
| } catch (RemoteException e) { |
| throw e.rethrowFromSystemServer(); |
| } catch (ServiceSpecificException e) { |
| throw wrapUnexpectedServiceSpecificException(e); |
| } |
| } |
| |
| /** |
| * Generates a recoverable key with the given {@code alias}. |
| * |
| * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery |
| * service. |
| * @throws LockScreenRequiredException if the user does not have a lock screen set. A lock |
| * screen is required to generate recoverable keys. |
| * |
| * @deprecated Use the method {@link #generateKey(String, byte[])} instead. |
| */ |
| @Deprecated |
| @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) |
| public @NonNull Key generateKey(@NonNull String alias) throws InternalRecoveryServiceException, |
| LockScreenRequiredException { |
| try { |
| String grantAlias = mBinder.generateKey(alias); |
| if (grantAlias == null) { |
| throw new InternalRecoveryServiceException("null grant alias"); |
| } |
| return getKeyFromGrant(grantAlias); |
| } catch (RemoteException e) { |
| throw e.rethrowFromSystemServer(); |
| } catch (KeyPermanentlyInvalidatedException | UnrecoverableKeyException e) { |
| throw new InternalRecoveryServiceException("Failed to get key from keystore", e); |
| } catch (ServiceSpecificException e) { |
| if (e.errorCode == ERROR_INSECURE_USER) { |
| throw new LockScreenRequiredException(e.getMessage()); |
| } |
| throw wrapUnexpectedServiceSpecificException(e); |
| } |
| } |
| |
| /** |
| * Generates a recoverable key with the given {@code alias} and {@code metadata}. |
| * |
| * <p>The metadata should contain any data that needs to be cryptographically bound to the |
| * generated key, but does not need to be encrypted by the key. For example, the metadata can |
| * be a byte string describing the algorithms and non-secret parameters to be used with the |
| * key. The supplied metadata can later be obtained via |
| * {@link WrappedApplicationKey#getMetadata()}. |
| * |
| * <p>During the key recovery process, the same metadata has to be supplied via |
| * {@link WrappedApplicationKey.Builder#setMetadata(byte[])}; otherwise, the recovery process |
| * will fail due to the checking of the cryptographic binding. This can help prevent |
| * potential attacks that try to swap key materials on the backup server and trick the |
| * application to use keys with different algorithms or parameters. |
| * |
| * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery |
| * service. |
| * @throws LockScreenRequiredException if the user does not have a lock screen set. A lock |
| * screen is required to generate recoverable keys. |
| */ |
| @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) |
| public @NonNull Key generateKey(@NonNull String alias, @Nullable byte[] metadata) |
| throws InternalRecoveryServiceException, LockScreenRequiredException { |
| try { |
| String grantAlias = mBinder.generateKeyWithMetadata(alias, metadata); |
| if (grantAlias == null) { |
| throw new InternalRecoveryServiceException("null grant alias"); |
| } |
| return getKeyFromGrant(grantAlias); |
| } catch (RemoteException e) { |
| throw e.rethrowFromSystemServer(); |
| } catch (KeyPermanentlyInvalidatedException | UnrecoverableKeyException e) { |
| throw new InternalRecoveryServiceException("Failed to get key from keystore", e); |
| } catch (ServiceSpecificException e) { |
| if (e.errorCode == ERROR_INSECURE_USER) { |
| throw new LockScreenRequiredException(e.getMessage()); |
| } |
| throw wrapUnexpectedServiceSpecificException(e); |
| } |
| } |
| |
| /** |
| * Imports a 256-bit recoverable AES key with the given {@code alias} and the raw bytes {@code |
| * keyBytes}. |
| * |
| * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery |
| * service. |
| * @throws LockScreenRequiredException if the user does not have a lock screen set. A lock |
| * screen is required to generate recoverable keys. |
| * |
| * @deprecated Use the method {@link #importKey(String, byte[], byte[])} instead. |
| */ |
| @Deprecated |
| @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) |
| public @NonNull Key importKey(@NonNull String alias, @NonNull byte[] keyBytes) |
| throws InternalRecoveryServiceException, LockScreenRequiredException { |
| try { |
| String grantAlias = mBinder.importKey(alias, keyBytes); |
| if (grantAlias == null) { |
| throw new InternalRecoveryServiceException("Null grant alias"); |
| } |
| return getKeyFromGrant(grantAlias); |
| } catch (RemoteException e) { |
| throw e.rethrowFromSystemServer(); |
| } catch (KeyPermanentlyInvalidatedException | UnrecoverableKeyException e) { |
| throw new InternalRecoveryServiceException("Failed to get key from keystore", e); |
| } catch (ServiceSpecificException e) { |
| if (e.errorCode == ERROR_INSECURE_USER) { |
| throw new LockScreenRequiredException(e.getMessage()); |
| } |
| throw wrapUnexpectedServiceSpecificException(e); |
| } |
| } |
| |
| /** |
| * Imports a recoverable 256-bit AES key with the given {@code alias}, the raw bytes {@code |
| * keyBytes}, and the {@code metadata}. |
| * |
| * <p>The metadata should contain any data that needs to be cryptographically bound to the |
| * imported key, but does not need to be encrypted by the key. For example, the metadata can |
| * be a byte string describing the algorithms and non-secret parameters to be used with the |
| * key. The supplied metadata can later be obtained via |
| * {@link WrappedApplicationKey#getMetadata()}. |
| * |
| * <p>During the key recovery process, the same metadata has to be supplied via |
| * {@link WrappedApplicationKey.Builder#setMetadata(byte[])}; otherwise, the recovery process |
| * will fail due to the checking of the cryptographic binding. This can help prevent |
| * potential attacks that try to swap key materials on the backup server and trick the |
| * application to use keys with different algorithms or parameters. |
| * |
| * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery |
| * service. |
| * @throws LockScreenRequiredException if the user does not have a lock screen set. A lock |
| * screen is required to generate recoverable keys. |
| */ |
| @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) |
| public @NonNull Key importKey(@NonNull String alias, @NonNull byte[] keyBytes, |
| @Nullable byte[] metadata) |
| throws InternalRecoveryServiceException, LockScreenRequiredException { |
| try { |
| String grantAlias = mBinder.importKeyWithMetadata(alias, keyBytes, metadata); |
| if (grantAlias == null) { |
| throw new InternalRecoveryServiceException("Null grant alias"); |
| } |
| return getKeyFromGrant(grantAlias); |
| } catch (RemoteException e) { |
| throw e.rethrowFromSystemServer(); |
| } catch (KeyPermanentlyInvalidatedException | UnrecoverableKeyException e) { |
| throw new InternalRecoveryServiceException("Failed to get key from keystore", e); |
| } catch (ServiceSpecificException e) { |
| if (e.errorCode == ERROR_INSECURE_USER) { |
| throw new LockScreenRequiredException(e.getMessage()); |
| } |
| throw wrapUnexpectedServiceSpecificException(e); |
| } |
| } |
| |
| /** |
| * Gets a key called {@code alias} from the recoverable key store. |
| * |
| * @param alias The key alias. |
| * @return The key. |
| * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery |
| * service. |
| * @throws UnrecoverableKeyException if key is permanently invalidated or not found. |
| */ |
| @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) |
| public @Nullable Key getKey(@NonNull String alias) |
| throws InternalRecoveryServiceException, UnrecoverableKeyException { |
| try { |
| String grantAlias = mBinder.getKey(alias); |
| if (grantAlias == null || "".equals(grantAlias)) { |
| return null; |
| } |
| return getKeyFromGrant(grantAlias); |
| } catch (RemoteException e) { |
| throw e.rethrowFromSystemServer(); |
| } catch (KeyPermanentlyInvalidatedException | UnrecoverableKeyException e) { |
| throw new UnrecoverableKeyException(e.getMessage()); |
| } catch (ServiceSpecificException e) { |
| throw wrapUnexpectedServiceSpecificException(e); |
| } |
| } |
| |
| /** |
| * Returns the key with the given {@code grantAlias}. |
| */ |
| @NonNull Key getKeyFromGrant(@NonNull String grantAlias) |
| throws UnrecoverableKeyException, KeyPermanentlyInvalidatedException { |
| return AndroidKeyStoreProvider.loadAndroidKeyStoreKeyFromKeystore( |
| mKeyStore, |
| grantAlias, |
| KeyStore.UID_SELF); |
| } |
| |
| /** |
| * Removes a key called {@code alias} from the recoverable key store. |
| * |
| * @param alias The key alias. |
| * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery |
| * service. |
| */ |
| @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) |
| public void removeKey(@NonNull String alias) throws InternalRecoveryServiceException { |
| try { |
| mBinder.removeKey(alias); |
| } catch (RemoteException e) { |
| throw e.rethrowFromSystemServer(); |
| } catch (ServiceSpecificException e) { |
| throw wrapUnexpectedServiceSpecificException(e); |
| } |
| } |
| |
| /** |
| * Returns a new {@link RecoverySession}. |
| * |
| * <p>A recovery session is required to restore keys from a remote store. |
| */ |
| @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) |
| public @NonNull RecoverySession createRecoverySession() { |
| return RecoverySession.newInstance(this); |
| } |
| |
| @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE) |
| public @NonNull Map<String, X509Certificate> getRootCertificates() { |
| return TrustedRootCertificates.getRootCertificates(); |
| } |
| |
| InternalRecoveryServiceException wrapUnexpectedServiceSpecificException( |
| ServiceSpecificException e) { |
| if (e.errorCode == ERROR_SERVICE_INTERNAL_ERROR) { |
| return new InternalRecoveryServiceException(e.getMessage()); |
| } |
| |
| // Should never happen. If it does, it's a bug, and we need to update how the method that |
| // called this throws its exceptions. |
| return new InternalRecoveryServiceException("Unexpected error code for method: " |
| + e.errorCode, e); |
| } |
| } |
