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/*==LICENSE==*
CyanWorlds.com Engine - MMOG client, server and tools
Copyright (C) 2011 Cyan Worlds, Inc.
This program 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.
This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
You can contact Cyan Worlds, Inc. by email legal@cyan.com
or by snail mail at:
Cyan Worlds, Inc.
14617 N Newport Hwy
Mead, WA 99021
*==LICENSE==*/
#include "plEncryptedStream.h"
#include "hsUtils.h"
#include "plFileUtils.h"
#include "hsSTLStream.h"
#include <time.h>
static const UInt32 kDefaultKey[4] = { 0x6c0a5452, 0x3827d0f, 0x3a170b92, 0x16db7fc2 };
static const int kEncryptChunkSize = 8;
static const char* kOldMagicString = "BriceIsSmart";
static const char* kMagicString = "whatdoyousee";
static const int kMagicStringLen = 12;
static const int kFileStartOffset = kMagicStringLen + sizeof(UInt32);
static const int kMaxBufferedFileSize = 10*1024;
plEncryptedStream::plEncryptedStream(UInt32* key) :
fRef(nil),
fActualFileSize(0),
fBufferedStream(false),
fRAMStream(nil),
fWriteFileName(nil),
fOpenMode(kOpenFail)
{
if (key)
memcpy(&fKey, key, sizeof(kDefaultKey));
else
memcpy(&fKey, &kDefaultKey, sizeof(kDefaultKey));
}
plEncryptedStream::~plEncryptedStream()
{
}
//
// Tiny Encryption Algorithm
// http://vader.brad.ac.uk/tea/tea.shtml
//
// A potential weakness in this implementation is the fact that a known value
// (length of the original file) is written at the start of the encrypted file. -Colin
//
// Oh, and also there's some kind of potential weakness in TEA that they fixed with XTEA,
// but frankly, who cares. No one is going to break the encryption, they'll just get the
// key out of the exe or memory.
//
void plEncryptedStream::IEncipher(UInt32* const v)
{
register unsigned long y=v[0], z=v[1], sum=0, delta=0x9E3779B9, n=32;
while (n-- > 0)
{
y += (z << 4 ^ z >> 5) + z ^ sum + fKey[sum&3];
sum += delta;
z += (y << 4 ^ y >> 5) + y ^ sum + fKey[sum>>11 & 3];
}
v[0]=y; v[1]=z;
}
void plEncryptedStream::IDecipher(UInt32* const v)
{
register unsigned long y=v[0], z=v[1], sum=0xC6EF3720, delta=0x9E3779B9, n=32;
// sum = delta<<5, in general sum = delta * n
while (n-- > 0)
{
z -= (y << 4 ^ y >> 5) + y ^ sum + fKey[sum>>11 & 3];
sum -= delta;
y -= (z << 4 ^ z >> 5) + z ^ sum + fKey[sum&3];
}
v[0]=y; v[1]=z;
}
hsBool plEncryptedStream::Open(const char* name, const char* mode)
{
wchar* wName = hsStringToWString(name);
wchar* wMode = hsStringToWString(mode);
hsBool ret = Open(wName, wMode);
delete [] wName;
delete [] wMode;
return ret;
}
hsBool plEncryptedStream::Open(const wchar* name, const wchar* mode)
{
if (wcscmp(mode, L"rb") == 0)
{
fRef = _wfopen(name, mode);
fPosition = 0;
if (!fRef)
return false;
// Make sure our special magic string is there
if (!ICheckMagicString(fRef))
{
fclose(fRef);
return false;
}
fread(&fActualFileSize, sizeof(UInt32), 1, fRef);
// The encrypted stream is inefficient if you do reads smaller than
// 8 bytes. Since we do a lot of those, any file under a size threshold
// is buffered in memory
if (fActualFileSize <= kMaxBufferedFileSize)
IBufferFile();
fOpenMode = kOpenRead;
return true;
}
else if (wcscmp(mode, L"wb") == 0)
{
fRAMStream = TRACKED_NEW hsVectorStream;
fWriteFileName = TRACKED_NEW wchar[wcslen(name) + 1];
wcscpy(fWriteFileName, name);
fPosition = 0;
fOpenMode = kOpenWrite;
fBufferedStream = true;
return true;
}
else
{
hsAssert(0, "Unsupported open mode");
fOpenMode = kOpenFail;
return false;
}
}
hsBool plEncryptedStream::Close()
{
int rtn = false;
if (fOpenMode == kOpenWrite)
{
fRAMStream->Rewind();
rtn = IWriteEncypted(fRAMStream, fWriteFileName);
}
if (fRef)
{
rtn = (fclose(fRef) == 0);
fRef = nil;
}
if (fRAMStream)
{
delete fRAMStream;
fRAMStream = nil;
}
if (fWriteFileName)
{
delete [] fWriteFileName;
fWriteFileName = nil;
}
fActualFileSize = 0;
fBufferedStream = false;
fOpenMode = kOpenFail;
return rtn;
}
UInt32 plEncryptedStream::IRead(UInt32 bytes, void* buffer)
{
if (!fRef)
return 0;
int numItems = (int)(::fread(buffer, 1 /*size*/, bytes /*count*/, fRef));
fBytesRead += numItems;
fPosition += numItems;
if ((unsigned)numItems < bytes) {
if (feof(fRef)) {
// EOF ocurred
char str[128];
sprintf(str, "Hit EOF on UNIX Read, only read %d out of requested %d bytes\n", numItems, bytes);
hsDebugMessage(str, 0);
}
else {
hsDebugMessage("Error on UNIX Read", ferror(fRef));
}
}
return numItems;
}
void plEncryptedStream::IBufferFile()
{
fRAMStream = TRACKED_NEW hsVectorStream;
char buf[1024];
while (!AtEnd())
{
UInt32 numRead = Read(1024, buf);
fRAMStream->Write(numRead, buf);
}
fRAMStream->Rewind();
fBufferedStream = true;
fclose(fRef);
fRef = nil;
fPosition = 0;
}
hsBool plEncryptedStream::AtEnd()
{
if (fBufferedStream)
return fRAMStream->AtEnd();
else
return (GetPosition() == fActualFileSize);
}
void plEncryptedStream::Skip(UInt32 delta)
{
if (fBufferedStream)
{
fRAMStream->Skip(delta);
fPosition = fRAMStream->GetPosition();
}
else if (fRef)
{
fBytesRead += delta;
fPosition += delta;
fseek(fRef, delta, SEEK_CUR);
}
}
void plEncryptedStream::Rewind()
{
if (fBufferedStream)
{
fRAMStream->Rewind();
fPosition = fRAMStream->GetPosition();
}
else if (fRef)
{
fBytesRead = 0;
fPosition = 0;
fseek(fRef, kFileStartOffset, SEEK_SET);
}
}
void plEncryptedStream::FastFwd()
{
if (fBufferedStream)
{
fRAMStream->FastFwd();
fPosition = fRAMStream->GetPosition();
}
else if (fRef)
{
fseek(fRef, kFileStartOffset+fActualFileSize, SEEK_SET);
fBytesRead = fPosition = ftell(fRef);
}
}
UInt32 plEncryptedStream::GetEOF()
{
return fActualFileSize;
}
UInt32 plEncryptedStream::Read(UInt32 bytes, void* buffer)
{
if (fBufferedStream)
{
UInt32 numRead = fRAMStream->Read(bytes, buffer);
fPosition = fRAMStream->GetPosition();
return numRead;
}
UInt32 startPos = fPosition;
// Offset into the first buffer (0 if we are aligned on a chunk, which means no extra block read)
UInt32 startChunkPos = startPos % kEncryptChunkSize;
// Amount of data in the partial first chunk (0 if we're aligned)
UInt32 startAmt = (startChunkPos != 0) ? hsMinimum(kEncryptChunkSize - startChunkPos, bytes) : 0;
UInt32 totalNumRead = IRead(bytes, buffer);
UInt32 numMidChunks = (totalNumRead - startAmt) / kEncryptChunkSize;
UInt32 endAmt = (totalNumRead - startAmt) % kEncryptChunkSize;
// If the start position is in the middle of a chunk we need to rewind and
// read that whole chunk in and decrypt it.
if (startChunkPos != 0)
{
// Move to the start of this chunk
SetPosition(startPos-startChunkPos);
// Read in the chunk and decrypt it
char buf[kEncryptChunkSize];
UInt32 numRead = IRead(kEncryptChunkSize, &buf);
IDecipher((UInt32*)&buf);
// Copy the relevant portion to the output buffer
memcpy(buffer, &buf[startChunkPos], startAmt);
SetPosition(startPos+totalNumRead);
}
if (numMidChunks != 0)
{
UInt32* bufferPos = (UInt32*)(((char*)buffer)+startAmt);
for (int i = 0; i < numMidChunks; i++)
{
// Decrypt chunk
IDecipher(bufferPos);
bufferPos += (kEncryptChunkSize / sizeof(UInt32));
}
}
if (endAmt != 0)
{
// Read in the final chunk and decrypt it
char buf[kEncryptChunkSize];
SetPosition(startPos + startAmt + numMidChunks*kEncryptChunkSize);
UInt32 numRead = IRead(kEncryptChunkSize, &buf);
IDecipher((UInt32*)&buf);
memcpy(((char*)buffer)+totalNumRead-endAmt, &buf, endAmt);
SetPosition(startPos+totalNumRead);
}
// If we read into the padding at the end, update the total read to not include that
if (totalNumRead > 0 && startPos + totalNumRead > fActualFileSize)
{
totalNumRead -= (startPos + totalNumRead) - fActualFileSize;
SetPosition(fActualFileSize);
}
return totalNumRead;
}
UInt32 plEncryptedStream::Write(UInt32 bytes, const void* buffer)
{
if (fOpenMode != kOpenWrite)
{
hsAssert(0, "Trying to write to a read stream");
return 0;
}
return fRAMStream->Write(bytes, buffer);
}
bool plEncryptedStream::IWriteEncypted(hsStream* sourceStream, const wchar* outputFile)
{
hsUNIXStream outputStream;
if (!outputStream.Open(outputFile, L"wb"))
return false;
outputStream.Write(kMagicStringLen, kMagicString);
// Save some space to write the file size at the end
outputStream.WriteSwap32(0);
// Write out all the full size encrypted blocks we can
char buf[kEncryptChunkSize];
UInt32 amtRead;
while ((amtRead = sourceStream->Read(kEncryptChunkSize, &buf)) == kEncryptChunkSize)
{
IEncipher((UInt32*)&buf);
outputStream.Write(kEncryptChunkSize, &buf);
}
// Pad with random data and write out the final partial block, if there is one
if (amtRead > 0)
{
static bool seededRand = false;
if (!seededRand)
{
seededRand = true;
srand((unsigned int)time(nil));
}
for (int i = amtRead; i < kEncryptChunkSize; i++)
buf[i] = rand();
IEncipher((UInt32*)&buf);
outputStream.Write(kEncryptChunkSize, &buf);
}
// Write the original file size at the start
UInt32 actualSize = sourceStream->GetPosition();
outputStream.Rewind();
outputStream.Skip(kMagicStringLen);
outputStream.WriteSwap32(actualSize);
outputStream.Close();
return true;
}
bool plEncryptedStream::FileEncrypt(const char* fileName)
{
wchar* wFilename = hsStringToWString(fileName);
bool ret = FileEncrypt(wFilename);
delete [] wFilename;
return ret;
}
bool plEncryptedStream::FileEncrypt(const wchar* fileName)
{
hsUNIXStream sIn;
if (!sIn.Open(fileName))
return false;
// Don't double encrypt any files
if (ICheckMagicString(sIn.GetFILE()))
{
sIn.Close();
return true;
}
sIn.Rewind();
plEncryptedStream sOut;
bool wroteEncrypted = sOut.IWriteEncypted(&sIn, L"crypt.dat");
sIn.Close();
sOut.Close();
if (wroteEncrypted)
{
plFileUtils::RemoveFile(fileName);
plFileUtils::FileMove(L"crypt.dat", fileName);
}
return true;
}
bool plEncryptedStream::FileDecrypt(const char* fileName)
{
wchar* wFilename = hsStringToWString(fileName);
bool ret = FileDecrypt(wFilename);
delete [] wFilename;
return ret;
}
bool plEncryptedStream::FileDecrypt(const wchar* fileName)
{
plEncryptedStream sIn;
if (!sIn.Open(fileName))
return false;
hsUNIXStream sOut;
if (!sOut.Open(L"crypt.dat", L"wb"))
{
sIn.Close();
return false;
}
char buf[1024];
while (!sIn.AtEnd())
{
UInt32 numRead = sIn.Read(sizeof(buf), buf);
sOut.Write(numRead, buf);
}
sIn.Close();
sOut.Close();
plFileUtils::RemoveFile(fileName);
plFileUtils::FileMove(L"crypt.dat", fileName);
return true;
}
bool plEncryptedStream::ICheckMagicString(FILE* fp)
{
char magicString[kMagicStringLen+1];
fread(&magicString, kMagicStringLen, 1, fp);
magicString[kMagicStringLen] = '\0';
return (hsStrEQ(magicString, kMagicString) || hsStrEQ(magicString, kOldMagicString));
}
bool plEncryptedStream::IsEncryptedFile(const char* fileName)
{
wchar* wFilename = hsStringToWString(fileName);
bool ret = IsEncryptedFile(wFilename);
delete [] wFilename;
return ret;
}
bool plEncryptedStream::IsEncryptedFile(const wchar* fileName)
{
FILE* fp = _wfopen(fileName, L"rb");
if (!fp)
return false;
bool isEncrypted = ICheckMagicString(fp);
fclose(fp);
return isEncrypted;
}
hsStream* plEncryptedStream::OpenEncryptedFile(const char* fileName, bool requireEncrypted, UInt32* cryptKey)
{
wchar* wFilename = hsStringToWString(fileName);
hsStream* ret = OpenEncryptedFile(wFilename, requireEncrypted, cryptKey);
delete [] wFilename;
return ret;
}
hsStream* plEncryptedStream::OpenEncryptedFile(const wchar* fileName, bool requireEncrypted, UInt32* cryptKey)
{
#ifndef PLASMA_EXTERNAL_RELEASE
requireEncrypted = false;
#endif
bool isEncrypted = IsEncryptedFile(fileName);
hsStream* s = nil;
if (isEncrypted)
s = TRACKED_NEW plEncryptedStream(cryptKey);
// If this isn't an external release, let them use unencrypted data
else
if (!requireEncrypted)
s = TRACKED_NEW hsUNIXStream;
if (s)
s->Open(fileName, L"rb");
return s;
}
hsStream* plEncryptedStream::OpenEncryptedFileWrite(const char* fileName, UInt32* cryptKey)
{
wchar* wFilename = hsStringToWString(fileName);
hsStream* ret = OpenEncryptedFileWrite(wFilename, cryptKey);
delete [] wFilename;
return ret;
}
hsStream* plEncryptedStream::OpenEncryptedFileWrite(const wchar* fileName, UInt32* cryptKey)
{
hsStream* s = nil;
#ifdef PLASMA_EXTERNAL_RELEASE
s = TRACKED_NEW plEncryptedStream(cryptKey);
#else
s = TRACKED_NEW hsUNIXStream;
#endif
s->Open(fileName, L"wb");
return s;
}