| /* ==================================================================== |
| 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.agile; |
| |
| import static org.apache.poi.poifs.crypt.CryptoFunctions.generateIv; |
| import static org.apache.poi.poifs.crypt.CryptoFunctions.generateKey; |
| import static org.apache.poi.poifs.crypt.CryptoFunctions.getBlock0; |
| import static org.apache.poi.poifs.crypt.CryptoFunctions.getCipher; |
| import static org.apache.poi.poifs.crypt.CryptoFunctions.getMessageDigest; |
| import static org.apache.poi.poifs.crypt.CryptoFunctions.hashPassword; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.nio.ByteBuffer; |
| import java.security.GeneralSecurityException; |
| import java.security.MessageDigest; |
| import java.security.spec.AlgorithmParameterSpec; |
| import java.util.Arrays; |
| |
| import javax.crypto.Cipher; |
| import javax.crypto.SecretKey; |
| import javax.crypto.spec.IvParameterSpec; |
| import javax.crypto.spec.RC2ParameterSpec; |
| import javax.crypto.spec.SecretKeySpec; |
| |
| import org.apache.poi.EncryptedDocumentException; |
| import org.apache.poi.poifs.crypt.ChainingMode; |
| import org.apache.poi.poifs.crypt.ChunkedCipherInputStream; |
| import org.apache.poi.poifs.crypt.CipherAlgorithm; |
| 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.HashAlgorithm; |
| import org.apache.poi.poifs.filesystem.DirectoryNode; |
| import org.apache.poi.poifs.filesystem.DocumentInputStream; |
| import org.apache.poi.util.LittleEndian; |
| |
| /** |
| * Decryptor implementation for Agile Encryption |
| */ |
| public class AgileDecryptor extends Decryptor { |
| static final byte[] kVerifierInputBlock = longToBytes(0xfea7d2763b4b9e79L); |
| static final byte[] kHashedVerifierBlock = longToBytes(0xd7aa0f6d3061344eL); |
| static final byte[] kCryptoKeyBlock = longToBytes(0x146e0be7abacd0d6L); |
| static final byte[] kIntegrityKeyBlock = longToBytes(0x5fb2ad010cb9e1f6L); |
| static final byte[] kIntegrityValueBlock = longToBytes(0xa0677f02b22c8433L); |
| |
| private long _length = -1; |
| |
| protected AgileDecryptor() { |
| } |
| |
| protected AgileDecryptor(AgileDecryptor other) { |
| super(other); |
| _length = other._length; |
| } |
| |
| private static byte[] longToBytes(long l) { |
| return ByteBuffer.allocate(Long.BYTES).putLong(l).array(); |
| } |
| |
| /** |
| * set decryption password |
| */ |
| @Override |
| public boolean verifyPassword(String password) throws GeneralSecurityException { |
| AgileEncryptionVerifier ver = (AgileEncryptionVerifier)getEncryptionInfo().getVerifier(); |
| AgileEncryptionHeader header = (AgileEncryptionHeader)getEncryptionInfo().getHeader(); |
| |
| int blockSize = header.getBlockSize(); |
| |
| byte[] pwHash = hashPassword(password, ver.getHashAlgorithm(), ver.getSalt(), ver.getSpinCount()); |
| |
| /* |
| * encryptedVerifierHashInput: This attribute MUST be generated by using the following steps: |
| * 1. Generate a random array of bytes with the number of bytes used specified by the saltSize |
| * attribute. |
| * 2. Generate an encryption key as specified in section 2.3.4.11 by using the user-supplied password, |
| * the binary byte array used to create the saltValue attribute, and a blockKey byte array |
| * consisting of the following bytes: 0xfe, 0xa7, 0xd2, 0x76, 0x3b, 0x4b, 0x9e, and 0x79. |
| * 3. Encrypt the random array of bytes generated in step 1 by using the binary form of the saltValue |
| * attribute as an initialization vector as specified in section 2.3.4.12. If the array of bytes is not an |
| * integral multiple of blockSize bytes, pad the array with 0x00 to the next integral multiple of |
| * blockSize bytes. |
| * 4. Use base64 to encode the result of step 3. |
| */ |
| byte[] verfierInputEnc = hashInput(ver, pwHash, kVerifierInputBlock, ver.getEncryptedVerifier(), Cipher.DECRYPT_MODE); |
| setVerifier(verfierInputEnc); |
| MessageDigest hashMD = getMessageDigest(ver.getHashAlgorithm()); |
| byte[] verifierHash = hashMD.digest(verfierInputEnc); |
| |
| /* |
| * encryptedVerifierHashValue: This attribute MUST be generated by using the following steps: |
| * 1. Obtain the hash value of the random array of bytes generated in step 1 of the steps for |
| * encryptedVerifierHashInput. |
| * 2. Generate an encryption key as specified in section 2.3.4.11 by using the user-supplied password, |
| * the binary byte array used to create the saltValue attribute, and a blockKey byte array |
| * consisting of the following bytes: 0xd7, 0xaa, 0x0f, 0x6d, 0x30, 0x61, 0x34, and 0x4e. |
| * 3. Encrypt the hash value obtained in step 1 by using the binary form of the saltValue attribute as |
| * an initialization vector as specified in section 2.3.4.12. If hashSize is not an integral multiple of |
| * blockSize bytes, pad the hash value with 0x00 to an integral multiple of blockSize bytes. |
| * 4. Use base64 to encode the result of step 3. |
| */ |
| byte[] verifierHashDec = hashInput(ver, pwHash, kHashedVerifierBlock, ver.getEncryptedVerifierHash(), Cipher.DECRYPT_MODE); |
| verifierHashDec = getBlock0(verifierHashDec, ver.getHashAlgorithm().hashSize); |
| |
| /* |
| * encryptedKeyValue: This attribute MUST be generated by using the following steps: |
| * 1. Generate a random array of bytes that is the same size as specified by the |
| * Encryptor.KeyData.keyBits attribute of the parent element. |
| * 2. Generate an encryption key as specified in section 2.3.4.11, using the user-supplied password, |
| * the binary byte array used to create the saltValue attribute, and a blockKey byte array |
| * consisting of the following bytes: 0x14, 0x6e, 0x0b, 0xe7, 0xab, 0xac, 0xd0, and 0xd6. |
| * 3. Encrypt the random array of bytes generated in step 1 by using the binary form of the saltValue |
| * attribute as an initialization vector as specified in section 2.3.4.12. If the array of bytes is not an |
| * integral multiple of blockSize bytes, pad the array with 0x00 to an integral multiple of |
| * blockSize bytes. |
| * 4. Use base64 to encode the result of step 3. |
| */ |
| byte[] keyspec = hashInput(ver, pwHash, kCryptoKeyBlock, ver.getEncryptedKey(), Cipher.DECRYPT_MODE); |
| keyspec = getBlock0(keyspec, header.getKeySize()/8); |
| SecretKeySpec secretKey = new SecretKeySpec(keyspec, header.getCipherAlgorithm().jceId); |
| |
| /* |
| * 1. Obtain the intermediate key by decrypting the encryptedKeyValue from a KeyEncryptor |
| * contained within the KeyEncryptors sequence. Use this key for encryption operations in the |
| * remaining steps of this section. |
| * 2. Generate a random array of bytes, known as Salt, of the same length as the value of the |
| * KeyData.hashSize attribute. |
| * 3. Encrypt the random array of bytes generated in step 2 by using the binary form of the |
| * KeyData.saltValue attribute and a blockKey byte array consisting of the following bytes: 0x5f, |
| * 0xb2, 0xad, 0x01, 0x0c, 0xb9, 0xe1, and 0xf6 used to form an initialization vector as specified in |
| * section 2.3.4.12. If the array of bytes is not an integral multiple of blockSize bytes, pad the |
| * array with 0x00 to the next integral multiple of blockSize bytes. |
| * 4. Assign the encryptedHmacKey attribute to the base64-encoded form of the result of step 3. |
| */ |
| byte[] vec = CryptoFunctions.generateIv(header.getHashAlgorithm(), header.getKeySalt(), kIntegrityKeyBlock, blockSize); |
| CipherAlgorithm cipherAlgo = header.getCipherAlgorithm(); |
| Cipher cipher = getCipher(secretKey, cipherAlgo, header.getChainingMode(), vec, Cipher.DECRYPT_MODE); |
| byte[] hmacKey = cipher.doFinal(header.getEncryptedHmacKey()); |
| hmacKey = getBlock0(hmacKey, header.getHashAlgorithm().hashSize); |
| |
| /* |
| * 5. Generate an HMAC, as specified in [RFC2104], of the encrypted form of the data (message), |
| * which the DataIntegrity element will verify by using the Salt generated in step 2 as the key. |
| * Note that the entire EncryptedPackage stream (1), including the StreamSize field, MUST be |
| * used as the message. |
| * 6. Encrypt the HMAC as in step 3 by using a blockKey byte array consisting of the following bytes: |
| * 0xa0, 0x67, 0x7f, 0x02, 0xb2, 0x2c, 0x84, and 0x33. |
| * 7. Assign the encryptedHmacValue attribute to the base64-encoded form of the result of step 6. |
| */ |
| vec = CryptoFunctions.generateIv(header.getHashAlgorithm(), header.getKeySalt(), kIntegrityValueBlock, blockSize); |
| cipher = getCipher(secretKey, cipherAlgo, ver.getChainingMode(), vec, Cipher.DECRYPT_MODE); |
| byte[] hmacValue = cipher.doFinal(header.getEncryptedHmacValue()); |
| hmacValue = getBlock0(hmacValue, header.getHashAlgorithm().hashSize); |
| |
| if (Arrays.equals(verifierHashDec, verifierHash)) { |
| setSecretKey(secretKey); |
| setIntegrityHmacKey(hmacKey); |
| setIntegrityHmacValue(hmacValue); |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| protected static int getNextBlockSize(int inputLen, int blockSize) { |
| return (int)Math.ceil(inputLen / (double)blockSize) * blockSize; |
| } |
| |
| /* package */ static byte[] hashInput(AgileEncryptionVerifier ver, byte[] pwHash, byte[] blockKey, byte[] inputKey, int cipherMode) { |
| CipherAlgorithm cipherAlgo = ver.getCipherAlgorithm(); |
| ChainingMode chainMode = ver.getChainingMode(); |
| int keySize = ver.getKeySize()/8; |
| int blockSize = ver.getBlockSize(); |
| HashAlgorithm hashAlgo = ver.getHashAlgorithm(); |
| |
| byte[] intermedKey = generateKey(pwHash, hashAlgo, blockKey, keySize); |
| SecretKey skey = new SecretKeySpec(intermedKey, cipherAlgo.jceId); |
| byte[] iv = generateIv(hashAlgo, ver.getSalt(), null, blockSize); |
| Cipher cipher = getCipher(skey, cipherAlgo, chainMode, iv, cipherMode); |
| byte[] hashFinal; |
| |
| try { |
| inputKey = getBlock0(inputKey, getNextBlockSize(inputKey.length, blockSize)); |
| hashFinal = cipher.doFinal(inputKey); |
| return hashFinal; |
| } catch (GeneralSecurityException e) { |
| throw new EncryptedDocumentException(e); |
| } |
| } |
| |
| @SuppressWarnings({"java:S2095"}) |
| @Override |
| public InputStream getDataStream(DirectoryNode dir) throws IOException, GeneralSecurityException { |
| DocumentInputStream dis = dir.createDocumentInputStream(DEFAULT_POIFS_ENTRY); |
| _length = dis.readLong(); |
| return new AgileCipherInputStream(dis, _length); |
| } |
| |
| @Override |
| public long getLength(){ |
| if(_length == -1) { |
| throw new IllegalStateException("EcmaDecryptor.getDataStream() was not called"); |
| } |
| return _length; |
| } |
| |
| |
| protected static Cipher initCipherForBlock(Cipher existing, int block, boolean lastChunk, EncryptionInfo encryptionInfo, SecretKey skey, int encryptionMode) |
| throws GeneralSecurityException { |
| EncryptionHeader header = encryptionInfo.getHeader(); |
| String padding = (lastChunk ? "PKCS5Padding" : "NoPadding"); |
| if (existing == null || !existing.getAlgorithm().endsWith(padding)) { |
| existing = getCipher(skey, header.getCipherAlgorithm(), header.getChainingMode(), header.getKeySalt(), encryptionMode, padding); |
| } |
| |
| byte[] blockKey = new byte[4]; |
| LittleEndian.putInt(blockKey, 0, block); |
| byte[] iv = generateIv(header.getHashAlgorithm(), header.getKeySalt(), blockKey, header.getBlockSize()); |
| |
| AlgorithmParameterSpec aps; |
| if (header.getCipherAlgorithm() == CipherAlgorithm.rc2) { |
| aps = new RC2ParameterSpec(skey.getEncoded().length*8, iv); |
| } else { |
| aps = new IvParameterSpec(iv); |
| } |
| |
| existing.init(encryptionMode, skey, aps); |
| |
| return existing; |
| } |
| |
| /** |
| * 2.3.4.15 Data Encryption (Agile Encryption) |
| * |
| * The EncryptedPackage stream (1) MUST be encrypted in 4096-byte segments to facilitate nearly |
| * random access while allowing CBC modes to be used in the encryption process. |
| * The initialization vector for the encryption process MUST be obtained by using the zero-based |
| * segment number as a blockKey and the binary form of the KeyData.saltValue as specified in |
| * section 2.3.4.12. The block number MUST be represented as a 32-bit unsigned integer. |
| * Data blocks MUST then be encrypted by using the initialization vector and the intermediate key |
| * obtained by decrypting the encryptedKeyValue from a KeyEncryptor contained within the |
| * KeyEncryptors sequence as specified in section 2.3.4.10. The final data block MUST be padded to |
| * the next integral multiple of the KeyData.blockSize value. Any padding bytes can be used. Note |
| * that the StreamSize field of the EncryptedPackage field specifies the number of bytes of |
| * unencrypted data as specified in section 2.3.4.4. |
| */ |
| private class AgileCipherInputStream extends ChunkedCipherInputStream { |
| public AgileCipherInputStream(DocumentInputStream stream, long size) |
| throws GeneralSecurityException { |
| super(stream, size, 4096); |
| } |
| |
| // TODO: calculate integrity hmac while reading the stream |
| // for a post-validation of the data |
| |
| @Override |
| protected Cipher initCipherForBlock(Cipher cipher, int block) |
| throws GeneralSecurityException { |
| return AgileDecryptor.initCipherForBlock(cipher, block, false, getEncryptionInfo(), getSecretKey(), Cipher.DECRYPT_MODE); |
| } |
| } |
| |
| @Override |
| public AgileDecryptor copy() { |
| return new AgileDecryptor(this); |
| } |
| } |