| /* |
| * Copyright (C) 2015 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; |
| |
| import android.os.IBinder; |
| import android.security.KeyStore; |
| import android.security.KeyStoreException; |
| import android.security.keymaster.KeymasterArguments; |
| import android.security.keymaster.KeymasterDefs; |
| import android.security.keymaster.OperationResult; |
| |
| import java.security.InvalidAlgorithmParameterException; |
| import java.security.InvalidKeyException; |
| import java.security.Key; |
| import java.security.ProviderException; |
| import java.security.spec.AlgorithmParameterSpec; |
| |
| import javax.crypto.MacSpi; |
| |
| /** |
| * {@link MacSpi} which provides HMAC implementations backed by Android KeyStore. |
| * |
| * @hide |
| */ |
| public abstract class AndroidKeyStoreHmacSpi extends MacSpi implements KeyStoreCryptoOperation { |
| |
| public static class HmacSHA1 extends AndroidKeyStoreHmacSpi { |
| public HmacSHA1() { |
| super(KeymasterDefs.KM_DIGEST_SHA1); |
| } |
| } |
| |
| public static class HmacSHA224 extends AndroidKeyStoreHmacSpi { |
| public HmacSHA224() { |
| super(KeymasterDefs.KM_DIGEST_SHA_2_224); |
| } |
| } |
| |
| public static class HmacSHA256 extends AndroidKeyStoreHmacSpi { |
| public HmacSHA256() { |
| super(KeymasterDefs.KM_DIGEST_SHA_2_256); |
| } |
| } |
| |
| public static class HmacSHA384 extends AndroidKeyStoreHmacSpi { |
| public HmacSHA384() { |
| super(KeymasterDefs.KM_DIGEST_SHA_2_384); |
| } |
| } |
| |
| public static class HmacSHA512 extends AndroidKeyStoreHmacSpi { |
| public HmacSHA512() { |
| super(KeymasterDefs.KM_DIGEST_SHA_2_512); |
| } |
| } |
| |
| private final KeyStore mKeyStore = KeyStore.getInstance(); |
| private final int mKeymasterDigest; |
| private final int mMacSizeBits; |
| |
| // Fields below are populated by engineInit and should be preserved after engineDoFinal. |
| private AndroidKeyStoreSecretKey mKey; |
| |
| // Fields below are reset when engineDoFinal succeeds. |
| private KeyStoreCryptoOperationChunkedStreamer mChunkedStreamer; |
| private IBinder mOperationToken; |
| private long mOperationHandle; |
| |
| protected AndroidKeyStoreHmacSpi(int keymasterDigest) { |
| mKeymasterDigest = keymasterDigest; |
| mMacSizeBits = KeymasterUtils.getDigestOutputSizeBits(keymasterDigest); |
| } |
| |
| @Override |
| protected int engineGetMacLength() { |
| return (mMacSizeBits + 7) / 8; |
| } |
| |
| @Override |
| protected void engineInit(Key key, AlgorithmParameterSpec params) throws InvalidKeyException, |
| InvalidAlgorithmParameterException { |
| resetAll(); |
| |
| boolean success = false; |
| try { |
| init(key, params); |
| ensureKeystoreOperationInitialized(); |
| success = true; |
| } finally { |
| if (!success) { |
| resetAll(); |
| } |
| } |
| } |
| |
| private void init(Key key, AlgorithmParameterSpec params) throws InvalidKeyException, |
| InvalidAlgorithmParameterException { |
| if (key == null) { |
| throw new InvalidKeyException("key == null"); |
| } else if (!(key instanceof AndroidKeyStoreSecretKey)) { |
| throw new InvalidKeyException( |
| "Only Android KeyStore secret keys supported. Key: " + key); |
| } |
| mKey = (AndroidKeyStoreSecretKey) key; |
| |
| if (params != null) { |
| throw new InvalidAlgorithmParameterException( |
| "Unsupported algorithm parameters: " + params); |
| } |
| |
| } |
| |
| private void resetAll() { |
| mKey = null; |
| IBinder operationToken = mOperationToken; |
| if (operationToken != null) { |
| mKeyStore.abort(operationToken); |
| } |
| mOperationToken = null; |
| mOperationHandle = 0; |
| mChunkedStreamer = null; |
| } |
| |
| private void resetWhilePreservingInitState() { |
| IBinder operationToken = mOperationToken; |
| if (operationToken != null) { |
| mKeyStore.abort(operationToken); |
| } |
| mOperationToken = null; |
| mOperationHandle = 0; |
| mChunkedStreamer = null; |
| } |
| |
| @Override |
| protected void engineReset() { |
| resetWhilePreservingInitState(); |
| } |
| |
| private void ensureKeystoreOperationInitialized() throws InvalidKeyException { |
| if (mChunkedStreamer != null) { |
| return; |
| } |
| if (mKey == null) { |
| throw new IllegalStateException("Not initialized"); |
| } |
| |
| KeymasterArguments keymasterArgs = new KeymasterArguments(); |
| keymasterArgs.addEnum(KeymasterDefs.KM_TAG_ALGORITHM, KeymasterDefs.KM_ALGORITHM_HMAC); |
| keymasterArgs.addEnum(KeymasterDefs.KM_TAG_DIGEST, mKeymasterDigest); |
| keymasterArgs.addUnsignedInt(KeymasterDefs.KM_TAG_MAC_LENGTH, mMacSizeBits); |
| |
| OperationResult opResult = mKeyStore.begin( |
| mKey.getAlias(), |
| KeymasterDefs.KM_PURPOSE_SIGN, |
| true, |
| keymasterArgs, |
| null, // no additional entropy needed for HMAC because it's deterministic |
| mKey.getUid()); |
| |
| if (opResult == null) { |
| throw new KeyStoreConnectException(); |
| } |
| |
| // Store operation token and handle regardless of the error code returned by KeyStore to |
| // ensure that the operation gets aborted immediately if the code below throws an exception. |
| mOperationToken = opResult.token; |
| mOperationHandle = opResult.operationHandle; |
| |
| // If necessary, throw an exception due to KeyStore operation having failed. |
| InvalidKeyException e = KeyStoreCryptoOperationUtils.getInvalidKeyExceptionForInit( |
| mKeyStore, mKey, opResult.resultCode); |
| if (e != null) { |
| throw e; |
| } |
| |
| if (mOperationToken == null) { |
| throw new ProviderException("Keystore returned null operation token"); |
| } |
| if (mOperationHandle == 0) { |
| throw new ProviderException("Keystore returned invalid operation handle"); |
| } |
| |
| mChunkedStreamer = new KeyStoreCryptoOperationChunkedStreamer( |
| new KeyStoreCryptoOperationChunkedStreamer.MainDataStream( |
| mKeyStore, mOperationToken)); |
| } |
| |
| @Override |
| protected void engineUpdate(byte input) { |
| engineUpdate(new byte[] {input}, 0, 1); |
| } |
| |
| @Override |
| protected void engineUpdate(byte[] input, int offset, int len) { |
| try { |
| ensureKeystoreOperationInitialized(); |
| } catch (InvalidKeyException e) { |
| throw new ProviderException("Failed to reinitialize MAC", e); |
| } |
| |
| byte[] output; |
| try { |
| output = mChunkedStreamer.update(input, offset, len); |
| } catch (KeyStoreException e) { |
| throw new ProviderException("Keystore operation failed", e); |
| } |
| if ((output != null) && (output.length != 0)) { |
| throw new ProviderException("Update operation unexpectedly produced output"); |
| } |
| } |
| |
| @Override |
| protected byte[] engineDoFinal() { |
| try { |
| ensureKeystoreOperationInitialized(); |
| } catch (InvalidKeyException e) { |
| throw new ProviderException("Failed to reinitialize MAC", e); |
| } |
| |
| byte[] result; |
| try { |
| result = mChunkedStreamer.doFinal( |
| null, 0, 0, |
| null, // no signature provided -- this invocation will generate one |
| null // no additional entropy needed -- HMAC is deterministic |
| ); |
| } catch (KeyStoreException e) { |
| throw new ProviderException("Keystore operation failed", e); |
| } |
| |
| resetWhilePreservingInitState(); |
| return result; |
| } |
| |
| @Override |
| public void finalize() throws Throwable { |
| try { |
| IBinder operationToken = mOperationToken; |
| if (operationToken != null) { |
| mKeyStore.abort(operationToken); |
| } |
| } finally { |
| super.finalize(); |
| } |
| } |
| |
| @Override |
| public long getOperationHandle() { |
| return mOperationHandle; |
| } |
| } |