| /* ==================================================================== |
| Licensed to the Apache Software Foundation (ASF) under one or more |
| contributor license agreements. See the NOTICE file distributed with |
| this work for additional information regarding copyright ownership. |
| The ASF licenses this file to You 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 org.apache.poi.poifs.crypt.binaryrc4; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.security.GeneralSecurityException; |
| import java.security.MessageDigest; |
| import java.util.Arrays; |
| |
| import javax.crypto.Cipher; |
| import javax.crypto.SecretKey; |
| import javax.crypto.spec.SecretKeySpec; |
| |
| import org.apache.poi.EncryptedDocumentException; |
| import org.apache.poi.poifs.crypt.ChunkedCipherInputStream; |
| import org.apache.poi.poifs.crypt.CryptoFunctions; |
| import org.apache.poi.poifs.crypt.Decryptor; |
| import org.apache.poi.poifs.crypt.EncryptionHeader; |
| import org.apache.poi.poifs.crypt.EncryptionInfo; |
| import org.apache.poi.poifs.crypt.EncryptionVerifier; |
| import org.apache.poi.poifs.crypt.HashAlgorithm; |
| import org.apache.poi.poifs.filesystem.DirectoryNode; |
| import org.apache.poi.poifs.filesystem.DocumentInputStream; |
| import org.apache.poi.util.LittleEndian; |
| import org.apache.poi.util.StringUtil; |
| |
| public class BinaryRC4Decryptor extends Decryptor { |
| private long length = -1L; |
| private int chunkSize = 512; |
| |
| private class BinaryRC4CipherInputStream extends ChunkedCipherInputStream { |
| |
| @Override |
| protected Cipher initCipherForBlock(Cipher existing, int block) |
| throws GeneralSecurityException { |
| return BinaryRC4Decryptor.this.initCipherForBlock(existing, block); |
| } |
| |
| public BinaryRC4CipherInputStream(DocumentInputStream stream, long size) |
| throws GeneralSecurityException { |
| super(stream, size, chunkSize); |
| } |
| |
| public BinaryRC4CipherInputStream(InputStream stream, int size, int initialPos) |
| throws GeneralSecurityException { |
| super(stream, size, chunkSize, initialPos); |
| } |
| } |
| |
| protected BinaryRC4Decryptor() { |
| } |
| |
| protected BinaryRC4Decryptor(BinaryRC4Decryptor other) { |
| super(other); |
| length = other.length; |
| chunkSize = other.chunkSize; |
| } |
| |
| @Override |
| public boolean verifyPassword(String password) { |
| EncryptionVerifier ver = getEncryptionInfo().getVerifier(); |
| SecretKey skey = generateSecretKey(password, ver); |
| try { |
| Cipher cipher = initCipherForBlock(null, 0, getEncryptionInfo(), skey, Cipher.DECRYPT_MODE); |
| byte[] encryptedVerifier = ver.getEncryptedVerifier(); |
| byte[] verifier = new byte[encryptedVerifier.length]; |
| cipher.update(encryptedVerifier, 0, encryptedVerifier.length, verifier); |
| setVerifier(verifier); |
| byte[] encryptedVerifierHash = ver.getEncryptedVerifierHash(); |
| byte[] verifierHash = cipher.doFinal(encryptedVerifierHash); |
| HashAlgorithm hashAlgo = ver.getHashAlgorithm(); |
| MessageDigest hashAlg = CryptoFunctions.getMessageDigest(hashAlgo); |
| byte[] calcVerifierHash = hashAlg.digest(verifier); |
| if (Arrays.equals(calcVerifierHash, verifierHash)) { |
| setSecretKey(skey); |
| return true; |
| } |
| } catch (GeneralSecurityException e) { |
| throw new EncryptedDocumentException(e); |
| } |
| return false; |
| } |
| |
| @Override |
| public Cipher initCipherForBlock(Cipher cipher, int block) |
| throws GeneralSecurityException { |
| return initCipherForBlock(cipher, block, getEncryptionInfo(), getSecretKey(), Cipher.DECRYPT_MODE); |
| } |
| |
| protected static Cipher initCipherForBlock(Cipher cipher, int block, |
| EncryptionInfo encryptionInfo, SecretKey skey, int encryptMode) |
| throws GeneralSecurityException { |
| EncryptionVerifier ver = encryptionInfo.getVerifier(); |
| HashAlgorithm hashAlgo = ver.getHashAlgorithm(); |
| byte[] blockKey = new byte[4]; |
| LittleEndian.putUInt(blockKey, 0, block); |
| byte[] encKey = CryptoFunctions.generateKey(skey.getEncoded(), hashAlgo, blockKey, 16); |
| SecretKey key = new SecretKeySpec(encKey, skey.getAlgorithm()); |
| if (cipher == null) { |
| EncryptionHeader em = encryptionInfo.getHeader(); |
| cipher = CryptoFunctions.getCipher(key, em.getCipherAlgorithm(), null, null, encryptMode); |
| } else { |
| cipher.init(encryptMode, key); |
| } |
| return cipher; |
| } |
| |
| protected static SecretKey generateSecretKey(String password, EncryptionVerifier ver) { |
| if (password.length() > 255) { |
| password = password.substring(0, 255); |
| } |
| HashAlgorithm hashAlgo = ver.getHashAlgorithm(); |
| MessageDigest hashAlg = CryptoFunctions.getMessageDigest(hashAlgo); |
| byte[] hash = hashAlg.digest(StringUtil.getToUnicodeLE(password)); |
| byte[] salt = ver.getSalt(); |
| hashAlg.reset(); |
| for (int i = 0; i < 16; i++) { |
| hashAlg.update(hash, 0, 5); |
| hashAlg.update(salt); |
| } |
| |
| hash = Arrays.copyOf(hashAlg.digest(), 5); |
| return new SecretKeySpec(hash, ver.getCipherAlgorithm().jceId); |
| } |
| |
| @Override |
| @SuppressWarnings({"java:S2095","resource"}) |
| public ChunkedCipherInputStream getDataStream(DirectoryNode dir) throws IOException, |
| GeneralSecurityException { |
| DocumentInputStream dis = dir.createDocumentInputStream(DEFAULT_POIFS_ENTRY); |
| length = dis.readLong(); |
| return new BinaryRC4CipherInputStream(dis, length); |
| } |
| |
| @Override |
| public InputStream getDataStream(InputStream stream, int size, int initialPos) |
| throws IOException, GeneralSecurityException { |
| return new BinaryRC4CipherInputStream(stream, size, initialPos); |
| } |
| |
| |
| @Override |
| public long getLength() { |
| if (length == -1L) { |
| throw new IllegalStateException("Decryptor.getDataStream() was not called"); |
| } |
| |
| return length; |
| } |
| |
| @Override |
| public void setChunkSize(int chunkSize) { |
| this.chunkSize = chunkSize; |
| } |
| |
| @Override |
| public BinaryRC4Decryptor copy() { |
| return new BinaryRC4Decryptor(this); |
| } |
| } |