/* * Copyright (C) 2009 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; import android.app.ActivityThread; import android.app.Application; import android.app.KeyguardManager; import android.content.Context; import android.hardware.fingerprint.FingerprintManager; import android.os.Binder; import android.os.IBinder; import android.os.Process; import android.os.RemoteException; import android.os.ServiceManager; import android.os.UserHandle; import android.security.keymaster.ExportResult; import android.security.keymaster.KeyCharacteristics; import android.security.keymaster.KeymasterArguments; import android.security.keymaster.KeymasterBlob; import android.security.keymaster.KeymasterCertificateChain; import android.security.keymaster.KeymasterDefs; import android.security.keymaster.OperationResult; import android.security.keystore.KeyExpiredException; import android.security.keystore.KeyNotYetValidException; import android.security.keystore.KeyPermanentlyInvalidatedException; import android.security.keystore.UserNotAuthenticatedException; import android.util.Log; import java.math.BigInteger; import java.security.InvalidKeyException; import java.util.List; import java.util.Locale; /** * @hide This should not be made public in its present form because it * assumes that private and secret key bytes are available and would * preclude the use of hardware crypto. */ public class KeyStore { private static final String TAG = "KeyStore"; // ResponseCodes public static final int NO_ERROR = 1; public static final int LOCKED = 2; public static final int UNINITIALIZED = 3; public static final int SYSTEM_ERROR = 4; public static final int PROTOCOL_ERROR = 5; public static final int PERMISSION_DENIED = 6; public static final int KEY_NOT_FOUND = 7; public static final int VALUE_CORRUPTED = 8; public static final int UNDEFINED_ACTION = 9; public static final int WRONG_PASSWORD = 10; /** * Per operation authentication is needed before this operation is valid. * This is returned from {@link #begin} when begin succeeds but the operation uses * per-operation authentication and must authenticate before calling {@link #update} or * {@link #finish}. */ public static final int OP_AUTH_NEEDED = 15; // Used for UID field to indicate the calling UID. public static final int UID_SELF = -1; // Flags for "put" "import" and "generate" public static final int FLAG_NONE = 0; /** * Indicates that this key (or key pair) must be encrypted at rest. This will protect the key * (or key pair) with the secure lock screen credential (e.g., password, PIN, or pattern). * *

Note that this requires that the secure lock screen (e.g., password, PIN, pattern) is set * up, otherwise key (or key pair) generation or import will fail. Moreover, this key (or key * pair) will be deleted when the secure lock screen is disabled or reset (e.g., by the user or * a Device Administrator). Finally, this key (or key pair) cannot be used until the user * unlocks the secure lock screen after boot. * * @see KeyguardManager#isDeviceSecure() */ public static final int FLAG_ENCRYPTED = 1; /** * A private flag that's only available to system server to indicate that this key is part of * device encryption flow so it receives special treatment from keystore. For example this key * will not be super encrypted, and it will be stored separately under an unique UID instead * of the caller UID i.e. SYSTEM. * * Need to be in sync with KeyStoreFlag in system/security/keystore/include/keystore/keystore.h */ public static final int FLAG_CRITICAL_TO_DEVICE_ENCRYPTION = 1 << 3; // States public enum State { UNLOCKED, LOCKED, UNINITIALIZED }; private int mError = NO_ERROR; private final IKeystoreService mBinder; private final Context mContext; private IBinder mToken; private KeyStore(IKeystoreService binder) { mBinder = binder; mContext = getApplicationContext(); } public static Context getApplicationContext() { Application application = ActivityThread.currentApplication(); if (application == null) { throw new IllegalStateException( "Failed to obtain application Context from ActivityThread"); } return application; } public static KeyStore getInstance() { IKeystoreService keystore = IKeystoreService.Stub.asInterface(ServiceManager .getService("android.security.keystore")); return new KeyStore(keystore); } private synchronized IBinder getToken() { if (mToken == null) { mToken = new Binder(); } return mToken; } public State state(int userId) { final int ret; try { ret = mBinder.getState(userId); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); throw new AssertionError(e); } switch (ret) { case NO_ERROR: return State.UNLOCKED; case LOCKED: return State.LOCKED; case UNINITIALIZED: return State.UNINITIALIZED; default: throw new AssertionError(mError); } } public State state() { return state(UserHandle.myUserId()); } public boolean isUnlocked() { return state() == State.UNLOCKED; } public byte[] get(String key, int uid) { try { return mBinder.get(key, uid); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return null; } } public byte[] get(String key) { return get(key, UID_SELF); } public boolean put(String key, byte[] value, int uid, int flags) { return insert(key, value, uid, flags) == NO_ERROR; } public int insert(String key, byte[] value, int uid, int flags) { try { return mBinder.insert(key, value, uid, flags); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return SYSTEM_ERROR; } } public boolean delete(String key, int uid) { try { int ret = mBinder.del(key, uid); return (ret == NO_ERROR || ret == KEY_NOT_FOUND); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return false; } } public boolean delete(String key) { return delete(key, UID_SELF); } public boolean contains(String key, int uid) { try { return mBinder.exist(key, uid) == NO_ERROR; } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return false; } } public boolean contains(String key) { return contains(key, UID_SELF); } /** * List all entries in the keystore for {@code uid} starting with {@code prefix}. */ public String[] list(String prefix, int uid) { try { return mBinder.list(prefix, uid); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return null; } } public String[] list(String prefix) { return list(prefix, UID_SELF); } public boolean reset() { try { return mBinder.reset() == NO_ERROR; } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return false; } } /** * Attempt to lock the keystore for {@code user}. * * @param user Android user to lock. * @return whether {@code user}'s keystore was locked. */ public boolean lock(int userId) { try { return mBinder.lock(userId) == NO_ERROR; } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return false; } } public boolean lock() { return lock(UserHandle.myUserId()); } /** * Attempt to unlock the keystore for {@code user} with the password {@code password}. * This is required before keystore entries created with FLAG_ENCRYPTED can be accessed or * created. * * @param user Android user ID to operate on * @param password user's keystore password. Should be the most recent value passed to * {@link #onUserPasswordChanged} for the user. * * @return whether the keystore was unlocked. */ public boolean unlock(int userId, String password) { try { mError = mBinder.unlock(userId, password); return mError == NO_ERROR; } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return false; } } public boolean unlock(String password) { return unlock(UserHandle.getUserId(Process.myUid()), password); } /** * Check if the keystore for {@code userId} is empty. */ public boolean isEmpty(int userId) { try { return mBinder.isEmpty(userId) != 0; } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return false; } } public boolean isEmpty() { return isEmpty(UserHandle.myUserId()); } public boolean generate(String key, int uid, int keyType, int keySize, int flags, byte[][] args) { try { return mBinder.generate(key, uid, keyType, keySize, flags, new KeystoreArguments(args)) == NO_ERROR; } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return false; } } public boolean importKey(String keyName, byte[] key, int uid, int flags) { try { return mBinder.import_key(keyName, key, uid, flags) == NO_ERROR; } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return false; } } public byte[] sign(String key, byte[] data) { try { return mBinder.sign(key, data); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return null; } } public boolean verify(String key, byte[] data, byte[] signature) { try { return mBinder.verify(key, data, signature) == NO_ERROR; } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return false; } } public String grant(String key, int uid) { try { String grantAlias = mBinder.grant(key, uid); if (grantAlias == "") return null; return grantAlias; } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return null; } } public boolean ungrant(String key, int uid) { try { return mBinder.ungrant(key, uid) == NO_ERROR; } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return false; } } /** * Returns the last modification time of the key in milliseconds since the * epoch. Will return -1L if the key could not be found or other error. */ public long getmtime(String key, int uid) { try { final long millis = mBinder.getmtime(key, uid); if (millis == -1L) { return -1L; } return millis * 1000L; } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return -1L; } } public long getmtime(String key) { return getmtime(key, UID_SELF); } public boolean duplicate(String srcKey, int srcUid, String destKey, int destUid) { try { return mBinder.duplicate(srcKey, srcUid, destKey, destUid) == NO_ERROR; } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return false; } } // TODO: remove this when it's removed from Settings public boolean isHardwareBacked() { return isHardwareBacked("RSA"); } public boolean isHardwareBacked(String keyType) { try { return mBinder.is_hardware_backed(keyType.toUpperCase(Locale.US)) == NO_ERROR; } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return false; } } public boolean clearUid(int uid) { try { return mBinder.clear_uid(uid) == NO_ERROR; } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return false; } } public int getLastError() { return mError; } public boolean addRngEntropy(byte[] data) { try { return mBinder.addRngEntropy(data) == NO_ERROR; } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return false; } } public int generateKey(String alias, KeymasterArguments args, byte[] entropy, int uid, int flags, KeyCharacteristics outCharacteristics) { try { return mBinder.generateKey(alias, args, entropy, uid, flags, outCharacteristics); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return SYSTEM_ERROR; } } public int generateKey(String alias, KeymasterArguments args, byte[] entropy, int flags, KeyCharacteristics outCharacteristics) { return generateKey(alias, args, entropy, UID_SELF, flags, outCharacteristics); } public int getKeyCharacteristics(String alias, KeymasterBlob clientId, KeymasterBlob appId, int uid, KeyCharacteristics outCharacteristics) { try { return mBinder.getKeyCharacteristics(alias, clientId, appId, uid, outCharacteristics); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return SYSTEM_ERROR; } } public int getKeyCharacteristics(String alias, KeymasterBlob clientId, KeymasterBlob appId, KeyCharacteristics outCharacteristics) { return getKeyCharacteristics(alias, clientId, appId, UID_SELF, outCharacteristics); } public int importKey(String alias, KeymasterArguments args, int format, byte[] keyData, int uid, int flags, KeyCharacteristics outCharacteristics) { try { return mBinder.importKey(alias, args, format, keyData, uid, flags, outCharacteristics); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return SYSTEM_ERROR; } } public int importKey(String alias, KeymasterArguments args, int format, byte[] keyData, int flags, KeyCharacteristics outCharacteristics) { return importKey(alias, args, format, keyData, UID_SELF, flags, outCharacteristics); } public ExportResult exportKey(String alias, int format, KeymasterBlob clientId, KeymasterBlob appId, int uid) { try { return mBinder.exportKey(alias, format, clientId, appId, uid); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return null; } } public ExportResult exportKey(String alias, int format, KeymasterBlob clientId, KeymasterBlob appId) { return exportKey(alias, format, clientId, appId, UID_SELF); } public OperationResult begin(String alias, int purpose, boolean pruneable, KeymasterArguments args, byte[] entropy, int uid) { try { return mBinder.begin(getToken(), alias, purpose, pruneable, args, entropy, uid); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return null; } } public OperationResult begin(String alias, int purpose, boolean pruneable, KeymasterArguments args, byte[] entropy) { return begin(alias, purpose, pruneable, args, entropy, UID_SELF); } public OperationResult update(IBinder token, KeymasterArguments arguments, byte[] input) { try { return mBinder.update(token, arguments, input); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return null; } } public OperationResult finish(IBinder token, KeymasterArguments arguments, byte[] signature, byte[] entropy) { try { return mBinder.finish(token, arguments, signature, entropy); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return null; } } public OperationResult finish(IBinder token, KeymasterArguments arguments, byte[] signature) { return finish(token, arguments, signature, null); } public int abort(IBinder token) { try { return mBinder.abort(token); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return SYSTEM_ERROR; } } /** * Check if the operation referenced by {@code token} is currently authorized. * * @param token An operation token returned by a call to * {@link #begin(String, int, boolean, KeymasterArguments, byte[], KeymasterArguments) begin}. */ public boolean isOperationAuthorized(IBinder token) { try { return mBinder.isOperationAuthorized(token); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return false; } } /** * Add an authentication record to the keystore authorization table. * * @param authToken The packed bytes of a hw_auth_token_t to be provided to keymaster. * @return {@code KeyStore.NO_ERROR} on success, otherwise an error value corresponding to * a {@code KeymasterDefs.KM_ERROR_} value or {@code KeyStore} ResponseCode. */ public int addAuthToken(byte[] authToken) { try { return mBinder.addAuthToken(authToken); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return SYSTEM_ERROR; } } /** * Notify keystore that a user's password has changed. * * @param userId the user whose password changed. * @param newPassword the new password or "" if the password was removed. */ public boolean onUserPasswordChanged(int userId, String newPassword) { // Parcel.cpp doesn't support deserializing null strings and treats them as "". Make that // explicit here. if (newPassword == null) { newPassword = ""; } try { return mBinder.onUserPasswordChanged(userId, newPassword) == NO_ERROR; } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return false; } } /** * Notify keystore that a user was added. * * @param userId the new user. * @param parentId the parent of the new user, or -1 if the user has no parent. If parentId is * specified then the new user's keystore will be intialized with the same secure lockscreen * password as the parent. */ public void onUserAdded(int userId, int parentId) { try { mBinder.onUserAdded(userId, parentId); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); } } /** * Notify keystore that a user was added. * * @param userId the new user. */ public void onUserAdded(int userId) { onUserAdded(userId, -1); } /** * Notify keystore that a user was removed. * * @param userId the removed user. */ public void onUserRemoved(int userId) { try { mBinder.onUserRemoved(userId); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); } } public boolean onUserPasswordChanged(String newPassword) { return onUserPasswordChanged(UserHandle.getUserId(Process.myUid()), newPassword); } public int attestKey( String alias, KeymasterArguments params, KeymasterCertificateChain outChain) { try { return mBinder.attestKey(alias, params, outChain); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return SYSTEM_ERROR; } } public int attestDeviceIds(KeymasterArguments params, KeymasterCertificateChain outChain) { try { return mBinder.attestDeviceIds(params, outChain); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); return SYSTEM_ERROR; } } /** * Notify keystore that the device went off-body. */ public void onDeviceOffBody() { try { mBinder.onDeviceOffBody(); } catch (RemoteException e) { Log.w(TAG, "Cannot connect to keystore", e); } } /** * Returns a {@link KeyStoreException} corresponding to the provided keystore/keymaster error * code. */ public static KeyStoreException getKeyStoreException(int errorCode) { if (errorCode > 0) { // KeyStore layer error switch (errorCode) { case NO_ERROR: return new KeyStoreException(errorCode, "OK"); case LOCKED: return new KeyStoreException(errorCode, "User authentication required"); case UNINITIALIZED: return new KeyStoreException(errorCode, "Keystore not initialized"); case SYSTEM_ERROR: return new KeyStoreException(errorCode, "System error"); case PERMISSION_DENIED: return new KeyStoreException(errorCode, "Permission denied"); case KEY_NOT_FOUND: return new KeyStoreException(errorCode, "Key not found"); case VALUE_CORRUPTED: return new KeyStoreException(errorCode, "Key blob corrupted"); case OP_AUTH_NEEDED: return new KeyStoreException(errorCode, "Operation requires authorization"); default: return new KeyStoreException(errorCode, String.valueOf(errorCode)); } } else { // Keymaster layer error switch (errorCode) { case KeymasterDefs.KM_ERROR_INVALID_AUTHORIZATION_TIMEOUT: // The name of this parameter significantly differs between Keymaster and // framework APIs. Use the framework wording to make life easier for developers. return new KeyStoreException(errorCode, "Invalid user authentication validity duration"); default: return new KeyStoreException(errorCode, KeymasterDefs.getErrorMessage(errorCode)); } } } /** * Returns an {@link InvalidKeyException} corresponding to the provided * {@link KeyStoreException}. */ public InvalidKeyException getInvalidKeyException( String keystoreKeyAlias, int uid, KeyStoreException e) { switch (e.getErrorCode()) { case LOCKED: return new UserNotAuthenticatedException(); case KeymasterDefs.KM_ERROR_KEY_EXPIRED: return new KeyExpiredException(); case KeymasterDefs.KM_ERROR_KEY_NOT_YET_VALID: return new KeyNotYetValidException(); case KeymasterDefs.KM_ERROR_KEY_USER_NOT_AUTHENTICATED: case OP_AUTH_NEEDED: { // We now need to determine whether the key/operation can become usable if user // authentication is performed, or whether it can never become usable again. // User authentication requirements are contained in the key's characteristics. We // need to check whether these requirements can be be satisfied by asking the user // to authenticate. KeyCharacteristics keyCharacteristics = new KeyCharacteristics(); int getKeyCharacteristicsErrorCode = getKeyCharacteristics(keystoreKeyAlias, null, null, uid, keyCharacteristics); if (getKeyCharacteristicsErrorCode != NO_ERROR) { return new InvalidKeyException( "Failed to obtained key characteristics", getKeyStoreException(getKeyCharacteristicsErrorCode)); } List keySids = keyCharacteristics.getUnsignedLongs(KeymasterDefs.KM_TAG_USER_SECURE_ID); if (keySids.isEmpty()) { // Key is not bound to any SIDs -- no amount of authentication will help here. return new KeyPermanentlyInvalidatedException(); } long rootSid = GateKeeper.getSecureUserId(); if ((rootSid != 0) && (keySids.contains(KeymasterArguments.toUint64(rootSid)))) { // One of the key's SIDs is the current root SID -- user can be authenticated // against that SID. return new UserNotAuthenticatedException(); } long fingerprintOnlySid = getFingerprintOnlySid(); if ((fingerprintOnlySid != 0) && (keySids.contains(KeymasterArguments.toUint64(fingerprintOnlySid)))) { // One of the key's SIDs is the current fingerprint SID -- user can be // authenticated against that SID. return new UserNotAuthenticatedException(); } // None of the key's SIDs can ever be authenticated return new KeyPermanentlyInvalidatedException(); } case UNINITIALIZED: return new KeyPermanentlyInvalidatedException(); default: return new InvalidKeyException("Keystore operation failed", e); } } private long getFingerprintOnlySid() { FingerprintManager fingerprintManager = mContext.getSystemService(FingerprintManager.class); if (fingerprintManager == null) { return 0; } // TODO: Restore USE_FINGERPRINT permission check in // FingerprintManager.getAuthenticatorId once the ID is no longer needed here. return fingerprintManager.getAuthenticatorId(); } /** * Returns an {@link InvalidKeyException} corresponding to the provided keystore/keymaster error * code. */ public InvalidKeyException getInvalidKeyException(String keystoreKeyAlias, int uid, int errorCode) { return getInvalidKeyException(keystoreKeyAlias, uid, getKeyStoreException(errorCode)); } }