/*

Derived from source code of TrueCrypt 7.1a, which is

Copyright (c) 2008-2012 TrueCrypt Developers Association and which is governed

by the TrueCrypt License 3.0.

Modifications and additions to the original source code (contained in this file)

and all other portions of this file are Copyright (c) 2013-2017 IDRIX

and are governed by the Apache License 2.0 the full text of which is

contained in the file License.txt included in VeraCrypt binary and source

code distribution packages.

*/

#include "Crc32.h"

#include "EncryptionModeXTS.h"

#include "Pkcs5Kdf.h"

#include "Pkcs5Kdf.h"

#include "VolumeHeader.h"

#include "VolumeException.h"

#include "Common/Crypto.h"

namespace VeraCrypt

{

VolumeHeader::VolumeHeader (uint32 size)

{

Init();

HeaderSize = size;

EncryptedHeaderDataSize = size - EncryptedHeaderDataOffset;

}

VolumeHeader::~VolumeHeader ()

{

Init();

}

void VolumeHeader::Init ()

{

VolumeKeyAreaCrc32 = 0;

VolumeCreationTime = 0;

HeaderCreationTime = 0;

mVolumeType = VolumeType::Unknown;

HiddenVolumeDataSize = 0;

VolumeDataSize = 0;

EncryptedAreaStart = 0;

EncryptedAreaLength = 0;

Flags = 0;

SectorSize = 0;

}

void VolumeHeader::Create (const BufferPtr &headerBuffer, VolumeHeaderCreationOptions &options)

{

if (options.DataKey.Size() != options.EA->GetKeySize() * 2 || options.Salt.Size() != GetSaltSize())

throw ParameterIncorrect (SRC_POS);

headerBuffer.Zero();

HeaderVersion = CurrentHeaderVersion;

RequiredMinProgramVersion = CurrentRequiredMinProgramVersion;

DataAreaKey.Zero();

DataAreaKey.CopyFrom (options.DataKey);

VolumeCreationTime = 0;

HiddenVolumeDataSize = (options.Type == VolumeType::Hidden ? options.VolumeDataSize : 0);

VolumeDataSize = options.VolumeDataSize;

EncryptedAreaStart = options.VolumeDataStart;

EncryptedAreaLength = options.VolumeDataSize;

SectorSize = options.SectorSize;

if (SectorSize < TC_MIN_VOLUME_SECTOR_SIZE

|| SectorSize > TC_MAX_VOLUME_SECTOR_SIZE

|| SectorSize % ENCRYPTION_DATA_UNIT_SIZE != 0)

{

throw ParameterIncorrect (SRC_POS);

}

EA = options.EA;

EncryptNew (headerBuffer, options.Salt, options.HeaderKey, options.Kdf);

}

bool VolumeHeader::Decrypt (const ConstBufferPtr &encryptedData, const VolumePassword &password, int pim, shared_ptr <Pkcs5Kdf> kdf, const Pkcs5KdfList &keyDerivationFunctions, const EncryptionAlgorithmList &encryptionAlgorithms, const EncryptionModeList &encryptionModes)

{

if (password.Size() < 1)

throw PasswordEmpty (SRC_POS);

ConstBufferPtr salt (encryptedData.GetRange (SaltOffset, SaltSize));

SecureBuffer header (EncryptedHeaderDataSize);

SecureBuffer headerKey (GetLargestSerializedKeySize());

foreach (shared_ptr <Pkcs5Kdf> pkcs5, keyDerivationFunctions)

{

if (kdf && (kdf->GetName() != pkcs5->GetName()))

continue;

pkcs5->DeriveKey (headerKey, password, pim, salt);

foreach (shared_ptr <EncryptionMode> mode, encryptionModes)

{

foreach (shared_ptr <EncryptionAlgorithm> ea, encryptionAlgorithms)

{

if (!ea->IsModeSupported (mode))

continue;

if (typeid (*mode) == typeid (EncryptionModeXTS))

{

mode = mode->GetNew();

mode->SetKey (headerKey.GetRange (ea->GetKeySize(), ea->GetKeySize()));

}

else

{

ea->SetKey (headerKey.GetRange (LegacyEncryptionModeKeyAreaSize, ea->GetKeySize()));

}

ea->SetMode (mode);

header.CopyFrom (encryptedData.GetRange (EncryptedHeaderDataOffset, EncryptedHeaderDataSize));

ea->Decrypt (header);

if (Deserialize (header, ea, mode))

{

EA = ea;

Pkcs5 = pkcs5;

return true;

}

}

}

}

return false;

}

bool VolumeHeader::Deserialize (const ConstBufferPtr &header, shared_ptr <EncryptionAlgorithm> &ea, shared_ptr <EncryptionMode> &mode)

{

if (header.Size() != EncryptedHeaderDataSize)

EncryptedAreaStart = DeserializeEntry <uint64> (header, offset);

EncryptedAreaLength = DeserializeEntry <uint64> (header, offset);

Flags = DeserializeEntry <uint32> (header, offset);

SectorSize = DeserializeEntry <uint32> (header, offset);

if (HeaderVersion < 5)

SectorSize = TC_SECTOR_SIZE_LEGACY;

if (SectorSize < TC_MIN_VOLUME_SECTOR_SIZE

|| SectorSize > TC_MAX_VOLUME_SECTOR_SIZE

|| SectorSize % ENCRYPTION_DATA_UNIT_SIZE != 0)

{

throw ParameterIncorrect (SRC_POS);

}

#if !(defined (TC_WINDOWS) || defined (TC_LINUX) || defined (TC_MACOSX))

if (SectorSize != TC_SECTOR_SIZE_LEGACY)

throw UnsupportedSectorSize (SRC_POS);

#endif

offset = DataAreaKeyOffset;

if (VolumeKeyAreaCrc32 != Crc32::ProcessBuffer (header.GetRange (offset, DataKeyAreaMaxSize)))

return false;

DataAreaKey.CopyFrom (header.GetRange (offset, DataKeyAreaMaxSize));

ea = ea->GetNew();

mode = mode->GetNew();

if (typeid (*mode) == typeid (EncryptionModeXTS))

{

mode->SetKey (header.GetRange (offset + ea->GetKeySize(), ea->GetKeySize()));

}

else

{

mode->SetKey (header.GetRange (offset, mode->GetKeySize()));

ea->SetKey (header.GetRange (offset + LegacyEncryptionModeKeyAreaSize, ea->GetKeySize()));

}

ea->SetMode (mode);

return true;

}

template <typename T>

T VolumeHeader::DeserializeEntry (const ConstBufferPtr &header, size_t &offset) const

{

offset += sizeof (T);

if (offset > header.Size())

throw ParameterIncorrect (SRC_POS);

return Endian::Big (*reinterpret_cast<const T *> (header.Get() + offset - sizeof (T)));

}

template <typename T>

T VolumeHeader::DeserializeEntryAt (const ConstBufferPtr &header, const size_t &offset) const

{

if (offset > header.Size())

throw ParameterIncorrect (SRC_POS);

return Endian::Big (*reinterpret_cast<const T *> (header.Get() + offset));

}

void VolumeHeader::EncryptNew (const BufferPtr &newHeaderBuffer, const ConstBufferPtr &newSalt, const ConstBufferPtr &newHeaderKey, shared_ptr <Pkcs5Kdf> newPkcs5Kdf)

{

if (newHeaderBuffer.Size() != HeaderSize || newSalt.Size() != SaltSize)

throw ParameterIncorrect (SRC_POS);

shared_ptr <EncryptionMode> mode = EA->GetMode()->GetNew();

shared_ptr <EncryptionAlgorithm> ea = EA->GetNew();

if (typeid (*mode) == typeid (EncryptionModeXTS))

{

}

else

{

mode->SetKey (newHeaderKey.GetRange (0, mode->GetKeySize()));

ea->SetKey (newHeaderKey.GetRange (LegacyEncryptionModeKeyAreaSize, ea->GetKeySize()));

}

ea->SetMode (mode);

newHeaderBuffer.CopyFrom (newSalt);

BufferPtr headerData = newHeaderBuffer.GetRange (EncryptedHeaderDataOffset, EncryptedHeaderDataSize);

Serialize (headerData);

ea->Encrypt (headerData);

if (newPkcs5Kdf)

Pkcs5 = newPkcs5Kdf;

}

size_t VolumeHeader::GetLargestSerializedKeySize ()

{

size_t largestKey = EncryptionAlgorithm::GetLargestKeySize (EncryptionAlgorithm::GetAvailableAlgorithms());

// XTS mode requires the same key size as the encryption algorithm.

// Legacy modes may require larger key than XTS.

if (LegacyEncryptionModeKeyAreaSize + largestKey > largestKey * 2)

return LegacyEncryptionModeKeyAreaSize + largestKey;

return largestKey * 2;

}