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Implement BufferedInputStream with one AesCtr section inside to work with it as with usual BufferedInputStream.
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Dmitry Isaenko 2022-09-09 02:44:40 +03:00
parent c542a23a8c
commit 3064970220
1 changed files with 246 additions and 0 deletions
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src/main/java/libKonogonka/ctraes/AesCtrBufferedInputStream.java Normal file
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/*
Copyright 2018-2022 Dmitry Isaenko
This file is part of libKonogonka.
libKonogonka is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
libKonogonka is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with libKonogonka. If not, see <https://www.gnu.org/licenses/>.
*/
package libKonogonka.ctraes;
import libKonogonka.RainbowDump;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import java.io.*;
public class AesCtrBufferedInputStream extends BufferedInputStream {
private final static Logger log = LogManager.getLogger(AesCtrBufferedInputStream.class);
private final AesCtrDecryptSimple decryptor;
private final long mediaOffsetPositionStart;
private final long mediaOffsetPositionEnd;
public AesCtrBufferedInputStream(AesCtrDecryptSimple decryptor,
long offsetPosition,
long mediaStartOffset,
long mediaEndOffset,
InputStream inputStream){
super(inputStream);
this.decryptor = decryptor;
this.mediaOffsetPositionStart = offsetPosition + (mediaStartOffset * 0x200);
this.mediaOffsetPositionEnd = offsetPosition + (mediaEndOffset * 0x200);
log.debug("\nOffset Position "+offsetPosition+
"\nMediaOffsetPositionStart "+RainbowDump.formatDecHexString(mediaOffsetPositionStart)+
"\nMediaOffsetPositionEnd "+RainbowDump.formatDecHexString(mediaOffsetPositionEnd));
}
private byte[] decryptedBytes;
private long pseudoPos;
private int pointerInsideDecryptedSection;
@Override
public synchronized int read(byte[] b) throws IOException {
int bytesToRead = b.length;
if (isPointerInsideEncryptedSection()){
int bytesFromFirstBlock = 0x200 - pointerInsideDecryptedSection;
if (bytesFromFirstBlock > bytesToRead){
log.trace("1.2. Pointer Inside + End Position Inside (Decrypted) Encrypted Section ("+pseudoPos+"-"+(pseudoPos+b.length)+")");
System.arraycopy(decryptedBytes, pointerInsideDecryptedSection, b, 0, bytesToRead);
log.error("!Pointer Inside Decrypted Section "+pointerInsideDecryptedSection+" "+(pointerInsideDecryptedSection+bytesToRead));
pseudoPos += bytesToRead;
pointerInsideDecryptedSection += bytesToRead;
return b.length;
}
if (isEndPositionInsideEncryptedSection(b.length)) {
log.trace("1.1. Pointer Inside + End Position Inside Encrypted Section ("+pseudoPos+"-"+(pseudoPos+b.length)+")");
int middleBlocksCount = (bytesToRead - bytesFromFirstBlock) / 0x200;
int bytesFromLastBlock = (bytesToRead - bytesFromFirstBlock) % 0x200;
//1
System.arraycopy(decryptedBytes, pointerInsideDecryptedSection, b, 0, bytesFromFirstBlock);
//2
for (int i = 0; i < middleBlocksCount; i++) {
fillDecryptedCache();
System.arraycopy(decryptedBytes, 0, b, bytesFromFirstBlock+i*0x200, 0x200);
}
//3 // TODO: ONLY IF NON-NULL??
fillDecryptedCache();
System.arraycopy(decryptedBytes, 0, b, bytesFromFirstBlock+middleBlocksCount*0x200, bytesFromLastBlock);
pseudoPos += bytesToRead;
pointerInsideDecryptedSection = bytesFromLastBlock;
return b.length;
}
log.trace("1. Pointer Inside + End Position Outside Encrypted Section ("+pseudoPos+"-"+(pseudoPos+b.length)+")");
int middleBlocksCount = (int) ((mediaOffsetPositionEnd - pseudoPos) / 0x200);
int bytesFromEnd = b.length - bytesFromFirstBlock - middleBlocksCount * 0x200;
//1
System.arraycopy(decryptedBytes, pointerInsideDecryptedSection, b, 0, bytesFromFirstBlock);
//2
//System.out.println("\n"+bytesFromFirstBlock+"\n"+ middleBlocksCount+" - "+(middleBlocksCount*0x200)+"\n"+ bytesFromEnd+"\n");
for (int i = 0; i < middleBlocksCount; i++) {
fillDecryptedCache();
System.arraycopy(decryptedBytes, 0, b, bytesFromFirstBlock+i*0x200, 0x200);
}
//3 // TODO: if it's zero?
System.arraycopy(readChunk(bytesFromEnd), 0, b, bytesFromFirstBlock+middleBlocksCount*0x200, bytesFromEnd);
pseudoPos += bytesToRead;
pointerInsideDecryptedSection = 0;
return b.length;
}
if (isEndPositionInsideEncryptedSection(bytesToRead)) {
log.trace("2. End Position Inside Encrypted Section ("+pseudoPos+"-"+(pseudoPos+b.length)+")");
int bytesTillEncrypted = (int) (mediaOffsetPositionStart - pos);
int fullEncryptedBlocks = (bytesToRead - bytesTillEncrypted) / 0x200;
int incompleteEncryptedBytes = (bytesToRead - bytesTillEncrypted) % 0x200;
System.arraycopy(readChunk(bytesTillEncrypted), 0, b, 0, bytesTillEncrypted);
//2
for (int i = 0; i < fullEncryptedBlocks; i++) {
fillDecryptedCache();
System.arraycopy(decryptedBytes, 0, b, fullEncryptedBlocks+i*0x200, 0x200);
}
//3
fillDecryptedCache();
System.arraycopy(decryptedBytes, 0, b, bytesTillEncrypted+fullEncryptedBlocks*0x200, incompleteEncryptedBytes);
pseudoPos += bytesToRead;
pointerInsideDecryptedSection = incompleteEncryptedBytes;
return b.length;
}
log.trace("3. Not encrypted ("+pseudoPos+"-"+(pseudoPos+b.length)+")");
pseudoPos += bytesToRead;
pointerInsideDecryptedSection = 0;
return super.read(b);
}
private void fillDecryptedCache() throws IOException{
try{
decryptedBytes = decryptor.decryptNext(readChunk(0x200));
}
catch (Exception e){
throw new IOException(e);
}
}
private void resetAndSkip(long blockSum) throws IOException{
try{
decryptor.reset();
decryptor.skipNext(blockSum); // recalculate
}
catch (Exception e){
throw new IOException(e);
}
}
private byte[] readChunk(int bytes) throws IOException{
byte[] chunkBytes = new byte[bytes];
long actuallyRead = super.read(chunkBytes);
if (actuallyRead != bytes)
throw new IOException("Can't read. Need block of "+ bytes +" while only " +
actuallyRead + " bytes.");
return chunkBytes;
}
private boolean isPointerInsideEncryptedSection(){
return (pseudoPos >= mediaOffsetPositionStart) && (pseudoPos < mediaOffsetPositionEnd);
}
private boolean isEndPositionInsideEncryptedSection(long requestedBytesCount){
return ((pseudoPos + requestedBytesCount) >= mediaOffsetPositionStart) && ((pseudoPos + requestedBytesCount) < mediaOffsetPositionEnd);
}
@Override
public synchronized long skip(long n) throws IOException {
if (isPointerInsideEncryptedSection()){
long realCountOfBytesToSkip = n - (0x200 - pointerInsideDecryptedSection);
if (realCountOfBytesToSkip <= 0){
pseudoPos += n;
pointerInsideDecryptedSection += n;
return n;
}
if (isEndPositionInsideEncryptedSection(n)){ // If we need to move somewhere out of the encrypted section
log.trace("4.1. Pointer Inside + End Position Inside Encrypted Section ("+pseudoPos+"-"+(pseudoPos+n)+")");
long blocksToSkipCountingFromStart = (pseudoPos+n - mediaOffsetPositionStart) / 0x200; // always positive
resetAndSkip(blocksToSkipCountingFromStart);
long leftovers = realCountOfBytesToSkip % 0x200; // most likely will be 0; TODO: a lot of tests
long bytesToSkipTillRequiredBlock = realCountOfBytesToSkip - leftovers;
long skipped = super.skip(bytesToSkipTillRequiredBlock);
if (bytesToSkipTillRequiredBlock != skipped)
throw new IOException("Can't skip bytes. To skip: " +
bytesToSkipTillRequiredBlock +
".\nActually skipped: " + skipped +
".\nLeftovers inside encrypted section: " + leftovers);
fillDecryptedCache();
pseudoPos += n;
pointerInsideDecryptedSection = (int) leftovers;
return n;
}
log.trace("4. Pointer Inside + End Position Outside Encrypted Section ("+pseudoPos+"-"+(pseudoPos+n)+")");
long skipped = super.skip(realCountOfBytesToSkip);
if (realCountOfBytesToSkip != skipped)
throw new IOException("Can't skip bytes. To skip: " +
realCountOfBytesToSkip +
".\nActually skipped: " + skipped);
pseudoPos += n;
pointerInsideDecryptedSection = 0;
return n;
// just fast-forward to position we need and flush caches
}
if (isEndPositionInsideEncryptedSection(n)) { //pointer will be inside Encrypted Section, but now outside
log.trace("5. End Position Inside Encrypted Section ("+pseudoPos+"-"+(pseudoPos+n)+")");
//skip to start if the block we need
long bytesToSkipTillEncryptedBlock = mediaOffsetPositionStart - pseudoPos; //TODO:FIX
long blocksToSkipCountingFromStart = (n - bytesToSkipTillEncryptedBlock) / 0x200; // always positive
long bytesToSkipTillRequiredBlock = bytesToSkipTillEncryptedBlock + blocksToSkipCountingFromStart * 0x200;
long leftovers = n - bytesToSkipTillRequiredBlock; // most likely will be 0;
long skipped = super.skip(bytesToSkipTillRequiredBlock);
if (bytesToSkipTillRequiredBlock != skipped)
throw new IOException("Can't skip bytes. To skip: " +
bytesToSkipTillEncryptedBlock +
".\nActually skipped: " + skipped +
".\nLeftovers inside encrypted section: " + leftovers);
resetAndSkip(blocksToSkipCountingFromStart);
fillDecryptedCache();
pseudoPos += n;
pointerInsideDecryptedSection = (int) leftovers;
return n;
}
log.trace("6. Not encrypted ("+pseudoPos+"-"+(pseudoPos+n)+")");
long skipped = super.skip(n);
pseudoPos += n;
pointerInsideDecryptedSection = 0;
return skipped;
}
@Override
public synchronized int read() throws IOException {
byte[] b = new byte[1];
if (read(b) != -1)
return b[0];
return -1;
}
@Override
public boolean markSupported() {
return false;
}
@Override
public synchronized void mark(int readlimit) {}
@Override
public synchronized void reset() throws IOException {
throw new IOException("Not supported");
}
}