| /* |
| * Copyright (C) 2019 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 com.android.internal.net.ipsec.ike.crypto; |
| |
| |
| import com.android.internal.net.crypto.KeyGenerationUtils.ByteSigner; |
| |
| import java.nio.ByteBuffer; |
| import java.security.GeneralSecurityException; |
| import java.security.NoSuchAlgorithmException; |
| |
| import javax.crypto.Mac; |
| import javax.crypto.spec.SecretKeySpec; |
| |
| /** |
| * IkeMac is an abstract class that represents common information for all negotiated algorithms that |
| * generates Message Authentication Code (MAC), e.g. PRF and integrity algorithm. |
| */ |
| abstract class IkeMac extends IkeCrypto implements ByteSigner { |
| private final boolean mIsJceSupported; |
| private final Mac mMac; |
| |
| protected IkeMac(int algorithmId, int keyLength, String algorithmName, boolean isJceSupported) { |
| super(algorithmId, keyLength, algorithmName); |
| |
| mIsJceSupported = isJceSupported; |
| |
| try { |
| if (mIsJceSupported) { |
| mMac = Mac.getInstance(getAlgorithmName()); |
| } else { |
| // Won't use javax.crypto.Mac for algorithm that is not supported by JCE. Will |
| // compute MAC using algorithm-specific implementation (e.g. AesXCbcImpl). |
| mMac = null; |
| } |
| } catch (NoSuchAlgorithmException e) { |
| throw new IllegalArgumentException("Failed to construct " + getTypeString(), e); |
| } |
| } |
| |
| /** |
| * Signs the bytes to generate a Message Authentication Code (MAC). |
| * |
| * <p>Caller is responsible for providing valid key according to their use cases (e.g. PSK, |
| * SK_p, SK_d ...). |
| * |
| * @param keyBytes the key to sign data. |
| * @param dataToSign the data to be signed. |
| * @return the calculated MAC. |
| */ |
| @Override |
| public byte[] signBytes(byte[] keyBytes, byte[] dataToSign) { |
| try { |
| if (mIsJceSupported) { |
| SecretKeySpec secretKey = new SecretKeySpec(keyBytes, getAlgorithmName()); |
| ByteBuffer inputBuffer = ByteBuffer.wrap(dataToSign); |
| mMac.init(secretKey); |
| mMac.update(inputBuffer); |
| |
| return mMac.doFinal(); |
| } else { |
| throw new IllegalStateException("Invalid algorithm: " + getAlgorithmId()); |
| } |
| } catch (GeneralSecurityException | IllegalStateException e) { |
| throw new IllegalArgumentException("Failed to generate MAC: ", e); |
| } |
| } |
| } |