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Implement random access for non-hashed files

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This commit is contained in:
Maschell 2019-04-07 00:10:36 +02:00
parent 57611173b4
commit 48f8629744
2 changed files with 71 additions and 10 deletions
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24
src/de/mas/wiiu/jnus/DecryptionService.java
View File

@ -220,7 +220,19 @@ public final class DecryptionService {
nusdecryption.decryptFileStreamHashed(inputStream, outputStream, size, offset, (short) contentIndex, h3);
} else {
nusdecryption.decryptFileStream(inputStream, outputStream, size, (short) contentIndex, content.getSHA2Hash(), encryptedFileSize);
try {
byte[] h3Hash = content.getSHA2Hash();
// We want to check if we read the whole file or just a part of it.
// There should be only one actual file inside a non-hashed content.
// But it could also contain a directory, so we need to filter.
long fstFileSize = content.getEntries().stream().filter(f -> !f.isDir()).findFirst().map(f -> f.getFileSize()).orElse(0L);
if (size > 0 && size < fstFileSize) {
h3Hash = null;
}
nusdecryption.decryptFileStream(inputStream, outputStream, size, offset, (short) contentIndex, h3Hash, encryptedFileSize);
} catch (Exception e) {
e.printStackTrace();
}
}
} else {
StreamUtils.saveInputStreamToOutputStreamWithHash(inputStream, outputStream, size, content.getSHA2Hash(), encryptedFileSize);
@ -285,9 +297,6 @@ public final class DecryptionService {
}
public byte[] getChunkFromFile(FSTEntry entry, long offset, long size) throws IOException, CheckSumWrongException {
if(!entry.getContent().isHashed()) {
throw new IOException("Only files from hashed contents are currently supported");
}
ByteArrayOutputStream out = new ByteArrayOutputStream();
long fileOffset = entry.getFileOffset() + offset;
@ -295,10 +304,15 @@ public final class DecryptionService {
if (entry.getContent().isHashed()) {
fileOffsetBlock = (fileOffset / 0xFC00) * 0x10000;
} else {
fileOffsetBlock = (fileOffset / 0x8000) * 0x8000;
// We need the previous IV if we don't start at the first block.
if (fileOffset >= 0x8000 && fileOffset % 0x8000 == 0) {
fileOffsetBlock -= 16;
}
}
decryptFSTEntryToStream(entry, out, size, fileOffset, fileOffsetBlock);
return out.toByteArray();
}

55
src/de/mas/wiiu/jnus/utils/cryptography/NUSDecryption.java
View File

@ -54,10 +54,11 @@ public class NUSDecryption extends AESDecryption {
return decrypt(blockBuffer, offset, BLOCKSIZE);
}
public void decryptFileStream(InputStream inputStream, OutputStream outputStream, long filesize, short contentIndex, byte[] h3hash,
public void decryptFileStream(InputStream inputStream, OutputStream outputStream, long filesize, long fileOffset, short contentIndex, byte[] h3hash,
long expectedSizeForHash) throws IOException, CheckSumWrongException {
MessageDigest sha1 = null;
MessageDigest sha1fallback = null;
if (h3hash != null) {
try {
sha1 = MessageDigest.getInstance("SHA1");
@ -84,21 +85,64 @@ public class NUSDecryption extends AESDecryption {
long written = 0;
long writtenFallback = 0;
int skipoffset = (int) (fileOffset % 0x8000);
// If we are at the beginning of a block, but it's not the first one,
// we need to get the IV from the last 16 bytes of the previous block.
// while beeing paranoid to exactly read 16 bytes but not more. Reading more
// would destroy our input stream.
// The input stream has been prepared to start 16 bytes earlier on this case.
if (fileOffset >= 0x8000 && fileOffset % 0x8000 == 0) {
int toRead = 16;
byte[] data = new byte[toRead];
int readTotal = 0;
while (readTotal < toRead) {
int res = inputStream.read(data, readTotal, toRead - readTotal);
if (res < 0) {
throw new IOException();
}
readTotal += res;
}
IV = Arrays.copyOfRange(data, 0, toRead);
}
ByteArrayBuffer overflow = new ByteArrayBuffer(BLOCKSIZE);
// We can only decrypt multiples of 16. So we need to align it.
long toRead = Utils.align(filesize + 15, 16);
do {
inBlockBuffer = StreamUtils.getChunkFromStream(inputStream, blockBuffer, overflow, BLOCKSIZE);
// In case we start on the middle of a block we need to consume the "garbage" and save the
// current IV.
if (skipoffset > 0) {
int skippedBytes = StreamUtils.getChunkFromStream(inputStream, blockBuffer, overflow, skipoffset);
if (skippedBytes > 16) {
IV = Arrays.copyOfRange(blockBuffer, skippedBytes - 16, skippedBytes);
}
skipoffset = 0;
}
int curReadSize = BLOCKSIZE;
if (toRead < BLOCKSIZE) {
curReadSize = (int) toRead;
}
inBlockBuffer = StreamUtils.getChunkFromStream(inputStream, blockBuffer, overflow, curReadSize);
byte[] output = decryptFileChunk(blockBuffer, (int) Utils.align(inBlockBuffer, 16), IV);
if (inBlockBuffer == BLOCKSIZE) {
IV = Arrays.copyOfRange(blockBuffer, BLOCKSIZE - 16, BLOCKSIZE);
}
int toWrite = inBlockBuffer;
if ((written + inBlockBuffer) > filesize) {
toWrite = (int) (filesize - written);
}
written += toWrite;
toRead -= toWrite;
outputStream.write(output, 0, toWrite);
@ -114,6 +158,9 @@ public class NUSDecryption extends AESDecryption {
sha1fallback.update(output, 0, (int) toFallback);
writtenFallback += toFallback;
}
if (written >= filesize && h3hash == null) {
break;
}
} while (inBlockBuffer == BLOCKSIZE);
if (sha1 != null && sha1fallback != null) {
@ -127,8 +174,8 @@ public class NUSDecryption extends AESDecryption {
byte[] calculated_hash2 = sha1fallback.digest();
byte[] expected_hash = h3hash;
if (!Arrays.equals(calculated_hash1, expected_hash) && !Arrays.equals(calculated_hash2, expected_hash)) {
outputStream.close();
inputStream.close();
outputStream.close();
throw new CheckSumWrongException("hash checksum failed", calculated_hash1, expected_hash);
} else {
@ -136,8 +183,8 @@ public class NUSDecryption extends AESDecryption {
}
}
outputStream.close();
inputStream.close();
outputStream.close();
}
public void decryptFileStreamHashed(InputStream inputStream, OutputStream outputStream, long filesize, long fileoffset, short contentIndex, byte[] h3Hash)