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Apache POI - Java API To Access Microsoft Format Files
/* ====================================================================
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.cryptoapi;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.security.GeneralSecurityException;
import java.security.MessageDigest;
import java.security.SecureRandom;
import java.util.ArrayList;
import java.util.List;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import org.apache.poi.EncryptedDocumentException;
import org.apache.poi.poifs.crypt.ChunkedCipherOutputStream;
import org.apache.poi.poifs.crypt.CryptoFunctions;
import org.apache.poi.poifs.crypt.EncryptionInfo;
import org.apache.poi.poifs.crypt.Encryptor;
import org.apache.poi.poifs.crypt.HashAlgorithm;
import org.apache.poi.poifs.crypt.cryptoapi.CryptoAPIDecryptor.StreamDescriptorEntry;
import org.apache.poi.poifs.filesystem.DirectoryNode;
import org.apache.poi.poifs.filesystem.DocumentInputStream;
import org.apache.poi.poifs.filesystem.Entry;
import org.apache.poi.poifs.filesystem.POIFSFileSystem;
import org.apache.poi.util.IOUtils;
import org.apache.poi.util.LittleEndian;
import org.apache.poi.util.RandomSingleton;
import org.apache.poi.util.StringUtil;
public class CryptoAPIEncryptor extends Encryptor {
private int chunkSize = 512;
CryptoAPIEncryptor() {}
CryptoAPIEncryptor(CryptoAPIEncryptor other) {
super(other);
chunkSize = other.chunkSize;
}
@Override
public void confirmPassword(String password) {
SecureRandom r = RandomSingleton.getInstance();
byte[] salt = new byte[16];
byte[] verifier = new byte[16];
// using a java.security.SecureRandom (and avoid allocating a new SecureRandom for each random number needed).
r.nextBytes(salt);
r.nextBytes(verifier);
confirmPassword(password, null, null, verifier, salt, null);
}
@Override
public void confirmPassword(String password, byte[] keySpec,
byte[] keySalt, byte[] verifier, byte[] verifierSalt,
byte[] integritySalt) {
assert(verifier != null && verifierSalt != null);
CryptoAPIEncryptionVerifier ver = (CryptoAPIEncryptionVerifier)getEncryptionInfo().getVerifier();
ver.setSalt(verifierSalt);
SecretKey skey = CryptoAPIDecryptor.generateSecretKey(password, ver);
setSecretKey(skey);
try {
Cipher cipher = initCipherForBlock(null, 0);
byte[] encryptedVerifier = new byte[verifier.length];
cipher.update(verifier, 0, verifier.length, encryptedVerifier);
ver.setEncryptedVerifier(encryptedVerifier);
HashAlgorithm hashAlgo = ver.getHashAlgorithm();
MessageDigest hashAlg = CryptoFunctions.getMessageDigest(hashAlgo);
byte[] calcVerifierHash = hashAlg.digest(verifier);
byte[] encryptedVerifierHash = cipher.doFinal(calcVerifierHash);
ver.setEncryptedVerifierHash(encryptedVerifierHash);
} catch (GeneralSecurityException e) {
throw new EncryptedDocumentException("Password confirmation failed", e);
}
}
/**
* Initializes a cipher object for a given block index for encryption
*
* @param cipher may be null, otherwise the given instance is reset to the new block index
* @param block the block index, e.g. the persist/slide id (hslf)
* @return a new cipher object, if cipher was null, otherwise the reinitialized cipher
* @throws GeneralSecurityException when the cipher can't be initialized
*/
public Cipher initCipherForBlock(Cipher cipher, int block)
throws GeneralSecurityException {
return CryptoAPIDecryptor.initCipherForBlock(cipher, block, getEncryptionInfo(), getSecretKey(), Cipher.ENCRYPT_MODE);
}
@Override
public ChunkedCipherOutputStream getDataStream(DirectoryNode dir) throws IOException {
throw new IOException("not supported");
}
@Override
public CryptoAPICipherOutputStream getDataStream(OutputStream stream, int initialOffset)
throws IOException, GeneralSecurityException {
return new CryptoAPICipherOutputStream(stream);
}
/**
* Encrypt the Document-/SummaryInformation and other optionally streams.
* Opposed to other crypto modes, cryptoapi is record based and can't be used
* to stream-encrypt a whole file
*
* @see 2.3.5.4 RC4 CryptoAPI Encrypted Summary Stream
*/
public void setSummaryEntries(DirectoryNode dir, String encryptedStream, POIFSFileSystem entries)
throws IOException, GeneralSecurityException {
CryptoAPIDocumentOutputStream bos = new CryptoAPIDocumentOutputStream(this); // NOSONAR
byte[] buf = new byte[8];
bos.write(buf, 0, 8); // skip header
List descList = new ArrayList<>();
int block = 0;
for (Entry entry : entries.getRoot()) {
if (entry.isDirectoryEntry()) {
continue;
}
StreamDescriptorEntry descEntry = new StreamDescriptorEntry();
descEntry.block = block;
descEntry.streamOffset = bos.size();
descEntry.streamName = entry.getName();
descEntry.flags = StreamDescriptorEntry.flagStream.setValue(0, 1);
descEntry.reserved2 = 0;
bos.setBlock(block);
try (DocumentInputStream dis = dir.createDocumentInputStream(entry)) {
IOUtils.copy(dis, bos);
}
descEntry.streamSize = bos.size() - descEntry.streamOffset;
descList.add(descEntry);
block++;
}
int streamDescriptorArrayOffset = bos.size();
bos.setBlock(0);
LittleEndian.putUInt(buf, 0, descList.size());
bos.write(buf, 0, 4);
for (StreamDescriptorEntry sde : descList) {
LittleEndian.putUInt(buf, 0, sde.streamOffset);
bos.write(buf, 0, 4);
LittleEndian.putUInt(buf, 0, sde.streamSize);
bos.write(buf, 0, 4);
LittleEndian.putUShort(buf, 0, sde.block);
bos.write(buf, 0, 2);
LittleEndian.putUByte(buf, 0, (short)sde.streamName.length());
bos.write(buf, 0, 1);
LittleEndian.putUByte(buf, 0, (short)sde.flags);
bos.write(buf, 0, 1);
LittleEndian.putUInt(buf, 0, sde.reserved2);
bos.write(buf, 0, 4);
byte[] nameBytes = StringUtil.getToUnicodeLE(sde.streamName);
bos.write(nameBytes, 0, nameBytes.length);
LittleEndian.putShort(buf, 0, (short)0); // null-termination
bos.write(buf, 0, 2);
}
int savedSize = bos.size();
int streamDescriptorArraySize = savedSize - streamDescriptorArrayOffset;
LittleEndian.putUInt(buf, 0, streamDescriptorArrayOffset);
LittleEndian.putUInt(buf, 4, streamDescriptorArraySize);
bos.reset();
bos.setBlock(0);
bos.write(buf, 0, 8);
bos.setSize(savedSize);
dir.createDocument(encryptedStream, bos.toInputStream(savedSize));
}
// protected int getKeySizeInBytes() {
// return getEncryptionInfo().getHeader().getKeySize() / 8;
// }
@Override
public void setChunkSize(int chunkSize) {
this.chunkSize = chunkSize;
}
@Override
public CryptoAPIEncryptor copy() {
return new CryptoAPIEncryptor(this);
}
protected class CryptoAPICipherOutputStream extends ChunkedCipherOutputStream {
@Override
protected Cipher initCipherForBlock(Cipher cipher, int block, boolean lastChunk)
throws IOException, GeneralSecurityException {
flush();
return initCipherForBlockNoFlush(cipher, block, lastChunk);
}
@Override
protected Cipher initCipherForBlockNoFlush(Cipher existing, int block, boolean lastChunk)
throws GeneralSecurityException {
EncryptionInfo ei = getEncryptionInfo();
SecretKey sk = getSecretKey();
return CryptoAPIDecryptor.initCipherForBlock(existing, block, ei, sk, Cipher.ENCRYPT_MODE);
}
@Override
protected void calculateChecksum(File file, int i) {
}
@Override
protected void createEncryptionInfoEntry(DirectoryNode dir, File tmpFile) {
throw new EncryptedDocumentException("createEncryptionInfoEntry not supported");
}
CryptoAPICipherOutputStream(OutputStream stream)
throws IOException, GeneralSecurityException {
super(stream, CryptoAPIEncryptor.this.chunkSize);
}
@Override
public void flush() throws IOException {
writeChunk(false);
super.flush();
}
}
}