org.apache.poi.poifs.crypt.ChunkedCipherOutputStream Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of poi Show documentation
Show all versions of poi Show documentation
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;
import static org.apache.poi.poifs.crypt.Decryptor.DEFAULT_POIFS_ENTRY;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.security.GeneralSecurityException;
import javax.crypto.Cipher;
import com.zaxxer.sparsebits.SparseBitSet;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.poi.EncryptedDocumentException;
import org.apache.poi.poifs.filesystem.DirectoryNode;
import org.apache.poi.poifs.filesystem.POIFSWriterEvent;
import org.apache.poi.util.IOUtils;
import org.apache.poi.util.Internal;
import org.apache.poi.util.LittleEndian;
import org.apache.poi.util.LittleEndianConsts;
import org.apache.poi.util.TempFile;
@Internal
public abstract class ChunkedCipherOutputStream extends FilterOutputStream {
private static final Logger LOG = LogManager.getLogger(ChunkedCipherOutputStream.class);
private static final int STREAMING = -1;
private final int chunkSize;
private final int chunkBits;
private final byte[] chunk;
private final SparseBitSet plainByteFlags;
private final File fileOut;
private final DirectoryNode dir;
private long pos;
private long totalPos;
private long written;
// the cipher can't be final, because for the last chunk we change the padding
// and therefore need to change the cipher too
private Cipher cipher;
private boolean isClosed;
public ChunkedCipherOutputStream(DirectoryNode dir, int chunkSize) throws IOException, GeneralSecurityException {
super(null);
this.chunkSize = chunkSize;
int cs = chunkSize == STREAMING ? 4096 : chunkSize;
this.chunk = IOUtils.safelyAllocate(cs, CryptoFunctions.MAX_RECORD_LENGTH);
this.plainByteFlags = new SparseBitSet(cs);
this.chunkBits = Integer.bitCount(cs-1);
this.fileOut = TempFile.createTempFile("encrypted_package", "crypt");
this.out = new FileOutputStream(fileOut);
this.dir = dir;
this.cipher = initCipherForBlock(null, 0, false);
}
public ChunkedCipherOutputStream(OutputStream stream, int chunkSize) throws IOException, GeneralSecurityException {
super(stream);
this.chunkSize = chunkSize;
int cs = chunkSize == STREAMING ? 4096 : chunkSize;
this.chunk = IOUtils.safelyAllocate(cs, CryptoFunctions.MAX_RECORD_LENGTH);
this.plainByteFlags = new SparseBitSet(cs);
this.chunkBits = Integer.bitCount(cs-1);
this.fileOut = null;
this.dir = null;
this.cipher = initCipherForBlock(null, 0, false);
}
public final Cipher initCipherForBlock(int block, boolean lastChunk) throws IOException, GeneralSecurityException {
return initCipherForBlock(cipher, block, lastChunk);
}
// helper method to break a recursion loop introduced because of an IBMJCE bug, i.e. not resetting on Cipher.doFinal()
@Internal
protected Cipher initCipherForBlockNoFlush(Cipher existing, int block, boolean lastChunk)
throws IOException, GeneralSecurityException {
return initCipherForBlock(cipher, block, lastChunk);
}
protected abstract Cipher initCipherForBlock(Cipher existing, int block, boolean lastChunk)
throws IOException, GeneralSecurityException;
protected abstract void calculateChecksum(File fileOut, int oleStreamSize)
throws GeneralSecurityException, IOException;
protected abstract void createEncryptionInfoEntry(DirectoryNode dir, File tmpFile)
throws IOException, GeneralSecurityException;
@Override
public void write(int b) throws IOException {
write(new byte[]{(byte)b});
}
@Override
public void write(byte[] b) throws IOException {
write(b, 0, b.length);
}
@Override
public void write(byte[] b, int off, int len) throws IOException {
write(b, off, len, false);
}
public void writePlain(byte[] b, int off, int len) throws IOException {
write(b, off, len, true);
}
protected void write(byte[] b, int off, int len, boolean writePlain) throws IOException {
if (len == 0) {
return;
}
if (len < 0 || b.length < off+len) {
throw new IOException("not enough bytes in your input buffer");
}
final int chunkMask = getChunkMask();
while (len > 0) {
int posInChunk = (int)(pos & chunkMask);
int nextLen = Math.min(chunk.length-posInChunk, len);
System.arraycopy(b, off, chunk, posInChunk, nextLen);
if (writePlain) {
plainByteFlags.set(posInChunk, posInChunk+nextLen);
}
pos += nextLen;
totalPos += nextLen;
off += nextLen;
len -= nextLen;
if ((pos & chunkMask) == 0) {
writeChunk(len > 0);
}
}
}
protected int getChunkMask() {
return chunk.length-1;
}
protected void writeChunk(boolean continued) throws IOException {
if (pos == 0 || totalPos == written) {
return;
}
int posInChunk = (int)(pos & getChunkMask());
// normally posInChunk is 0, i.e. on the next chunk (-> index-1)
// but if called on close(), posInChunk is somewhere within the chunk data
int index = (int)(pos >> chunkBits);
boolean lastChunk;
if (posInChunk==0) {
index--;
posInChunk = chunk.length;
lastChunk = false;
} else {
// pad the last chunk
lastChunk = true;
}
int ciLen;
try {
boolean doFinal = true;
long oldPos = pos;
// reset stream (not only) in case we were interrupted by plain stream parts
// this also needs to be set to prevent an endless loop
pos = 0;
if (chunkSize == STREAMING) {
if (continued) {
doFinal = false;
}
} else {
cipher = initCipherForBlock(cipher, index, lastChunk);
// restore pos - only streaming chunks will be reset
pos = oldPos;
}
ciLen = invokeCipher(posInChunk, doFinal);
} catch (GeneralSecurityException e) {
throw new IOException("can't re-/initialize cipher", e);
}
out.write(chunk, 0, ciLen);
plainByteFlags.clear();
written += ciLen;
}
/**
* Helper function for overriding the cipher invocation, i.e. XOR doesn't use a cipher
* and uses its own implementation
*/
protected int invokeCipher(int posInChunk, boolean doFinal) throws GeneralSecurityException, IOException {
byte[] plain = (plainByteFlags.isEmpty()) ? null : chunk.clone();
int ciLen = (doFinal)
? cipher.doFinal(chunk, 0, posInChunk, chunk)
: cipher.update(chunk, 0, posInChunk, chunk);
if (doFinal && "IBMJCE".equals(cipher.getProvider().getName()) && "RC4".equals(cipher.getAlgorithm())) {
// workaround for IBMs cipher not resetting on doFinal
int index = (int)(pos >> chunkBits);
boolean lastChunk;
if (posInChunk==0) {
index--;
posInChunk = chunk.length;
lastChunk = false;
} else {
// pad the last chunk
lastChunk = true;
}
cipher = initCipherForBlockNoFlush(cipher, index, lastChunk);
}
if (plain != null) {
int i = plainByteFlags.nextSetBit(0);
while (i >= 0 && i < posInChunk) {
chunk[i] = plain[i];
i = plainByteFlags.nextSetBit(i+1);
}
}
return ciLen;
}
@Override
public void close() throws IOException {
if (isClosed) {
LOG.atDebug().log("ChunkedCipherOutputStream was already closed - ignoring");
return;
}
isClosed = true;
try {
writeChunk(false);
super.close();
if (fileOut != null) {
int oleStreamSize = (int)(fileOut.length()+LittleEndianConsts.LONG_SIZE);
calculateChecksum(fileOut, (int)pos);
dir.createDocument(DEFAULT_POIFS_ENTRY, oleStreamSize, this::processPOIFSWriterEvent);
createEncryptionInfoEntry(dir, fileOut);
}
} catch (GeneralSecurityException e) {
throw new IOException(e);
} finally {
if (fileOut != null) {
if (!fileOut.delete()) {
//ignore
}
}
}
}
protected byte[] getChunk() {
return chunk;
}
protected SparseBitSet getPlainByteFlags() {
return plainByteFlags;
}
protected long getPos() {
return pos;
}
protected long getTotalPos() {
return totalPos;
}
/**
* Some ciphers (actually just XOR) are based on the record size,
* which needs to be set before encryption
*
* @param recordSize the size of the next record
* @param isPlain {@code true} if the record is unencrypted
*/
public void setNextRecordSize(int recordSize, boolean isPlain) {
}
private void processPOIFSWriterEvent(POIFSWriterEvent event) {
try {
try (OutputStream os = event.getStream();
FileInputStream fis = new FileInputStream(fileOut)) {
// StreamSize (8 bytes): An unsigned integer that specifies the number of bytes used by data
// encrypted within the EncryptedData field, not including the size of the StreamSize field.
// Note that the actual size of the \EncryptedPackage stream (1) can be larger than this
// value, depending on the block size of the chosen encryption algorithm
byte[] buf = new byte[LittleEndianConsts.LONG_SIZE];
LittleEndian.putLong(buf, 0, pos);
os.write(buf);
IOUtils.copy(fis, os);
}
if (!fileOut.delete()) {
LOG.atError().log("Can't delete temporary encryption file: {}", fileOut);
}
} catch (IOException e) {
throw new EncryptedDocumentException(e);
}
}
}