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VolumeWiiCrypted: Store last decrypted offset instead of block number 

This makes it unnecessary to reset m_last_decrypted_offset
when changing partition.
This commit is contained in:
JosJuice 2015-04-21 11:17:39 +02:00
parent 651340826d
commit 5c46810a36
2 changed files with 15 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
Source/Core/DiscIO/VolumeWiiCrypted.cpp
View File

@ -31,7 +31,7 @@ namespace DiscIO
CVolumeWiiCrypted::CVolumeWiiCrypted(std::unique_ptr<IBlobReader> reader, u64 _VolumeOffset,
const unsigned char* _pVolumeKey)
: m_pReader(std::move(reader)), m_AES_ctx(std::make_unique<mbedtls_aes_context>()),
m_VolumeOffset(_VolumeOffset), m_dataOffset(0x20000), m_LastDecryptedBlockOffset(-1)
m_VolumeOffset(_VolumeOffset), m_dataOffset(0x20000), m_last_decrypted_block(-1)
{
_assert_(m_pReader);
@ -41,7 +41,6 @@ CVolumeWiiCrypted::CVolumeWiiCrypted(std::unique_ptr<IBlobReader> reader, u64 _V
bool CVolumeWiiCrypted::ChangePartition(u64 offset)
{
m_VolumeOffset = offset;
m_LastDecryptedBlockOffset = -1;
u8 volume_key[16];
DiscIO::VolumeKeyForPartition(*m_pReader, offset, volume_key);
@ -61,25 +60,25 @@ bool CVolumeWiiCrypted::Read(u64 _ReadOffset, u64 _Length, u8* _pBuffer, bool de
std::vector<u8> read_buffer(BLOCK_TOTAL_SIZE);
while (_Length > 0)
{
// Calculate block offset
u64 Block = _ReadOffset / BLOCK_DATA_SIZE;
u64 Offset = _ReadOffset % BLOCK_DATA_SIZE;
// Calculate offsets
u64 block_offset_on_disc =
m_VolumeOffset + m_dataOffset + _ReadOffset / BLOCK_DATA_SIZE * BLOCK_TOTAL_SIZE;
u64 data_offset_in_block = _ReadOffset % BLOCK_DATA_SIZE;
if (m_LastDecryptedBlockOffset != Block)
if (m_last_decrypted_block != block_offset_on_disc)
{
// Read the current block
if (!m_pReader->Read(m_VolumeOffset + m_dataOffset + Block * BLOCK_TOTAL_SIZE,
BLOCK_TOTAL_SIZE, read_buffer.data()))
if (!m_pReader->Read(block_offset_on_disc, BLOCK_TOTAL_SIZE, read_buffer.data()))
return false;
// Decrypt the block's data.
// 0x3D0 - 0x3DF in m_pBuffer will be overwritten,
// 0x3D0 - 0x3DF in read_buffer will be overwritten,
// but that won't affect anything, because we won't
// use the content of m_pBuffer anymore after this
// use the content of read_buffer anymore after this
mbedtls_aes_crypt_cbc(m_AES_ctx.get(), MBEDTLS_AES_DECRYPT, BLOCK_DATA_SIZE,
&read_buffer[0x3D0], &read_buffer[BLOCK_HEADER_SIZE],
m_LastDecryptedBlock);
m_LastDecryptedBlockOffset = Block;
m_last_decrypted_block_data);
m_last_decrypted_block = block_offset_on_disc;
// The only thing we currently use from the 0x000 - 0x3FF part
// of the block is the IV (at 0x3D0), but it also contains SHA-1
@ -88,9 +87,9 @@ bool CVolumeWiiCrypted::Read(u64 _ReadOffset, u64 _Length, u8* _pBuffer, bool de
}
// Copy the decrypted data
u64 MaxSizeToCopy = BLOCK_DATA_SIZE - Offset;
u64 MaxSizeToCopy = BLOCK_DATA_SIZE - data_offset_in_block;
u64 CopySize = (_Length > MaxSizeToCopy) ? MaxSizeToCopy : _Length;
memcpy(_pBuffer, &m_LastDecryptedBlock[Offset], (size_t)CopySize);
memcpy(_pBuffer, &m_last_decrypted_block_data[data_offset_in_block], (size_t)CopySize);
// Update offsets
_Length -= CopySize;

4
Source/Core/DiscIO/VolumeWiiCrypted.h
View File

@ -68,8 +68,8 @@ private:
u64 m_VolumeOffset;
u64 m_dataOffset;
mutable u64 m_LastDecryptedBlockOffset;
mutable unsigned char m_LastDecryptedBlock[BLOCK_DATA_SIZE];
mutable u64 m_last_decrypted_block;
mutable u8 m_last_decrypted_block_data[BLOCK_DATA_SIZE];
};
} // namespace