You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
68 lines
2.5 KiB
68 lines
2.5 KiB
// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
|
|
// SPDX-License-Identifier: GPL-3.0-or-later
|
|
|
|
// SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
|
|
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
|
|
#include <algorithm>
|
|
#include <array>
|
|
#include <cstring>
|
|
#include "core/crypto/xts_encryption_layer.h"
|
|
|
|
namespace Core::Crypto {
|
|
|
|
constexpr std::size_t XTS_SECTOR_SIZE = 0x4000;
|
|
|
|
XTSEncryptionLayer::XTSEncryptionLayer(FileSys::VirtualFile base_, Key256 key_)
|
|
: EncryptionLayer(std::move(base_)), cipher(key_, Mode::XTS) {}
|
|
|
|
std::size_t XTSEncryptionLayer::Read(u8* data, std::size_t length, std::size_t offset) const {
|
|
if (length == 0)
|
|
return 0;
|
|
|
|
constexpr std::size_t PrefetchSectors = 4;
|
|
|
|
auto* out = data;
|
|
std::size_t remaining = length;
|
|
std::size_t current_offset = offset;
|
|
std::size_t total_read = 0;
|
|
|
|
std::array<u8, XTS_SECTOR_SIZE> sector{};
|
|
|
|
while (remaining > 0) {
|
|
const std::size_t sector_index = current_offset / XTS_SECTOR_SIZE;
|
|
const std::size_t sector_offset = current_offset % XTS_SECTOR_SIZE;
|
|
|
|
const std::size_t sectors_to_read = std::min<std::size_t>(PrefetchSectors,
|
|
(remaining + sector_offset +
|
|
XTS_SECTOR_SIZE - 1) /
|
|
XTS_SECTOR_SIZE);
|
|
|
|
for (std::size_t s = 0; s < sectors_to_read && remaining > 0; ++s) {
|
|
const std::size_t index = sector_index + s;
|
|
const std::size_t read_offset = index * XTS_SECTOR_SIZE;
|
|
const std::size_t got = base->Read(sector.data(), XTS_SECTOR_SIZE, read_offset);
|
|
if (got == 0)
|
|
return total_read;
|
|
|
|
if (got < XTS_SECTOR_SIZE)
|
|
std::memset(sector.data() + got, 0, XTS_SECTOR_SIZE - got);
|
|
|
|
cipher.XTSTranscode(sector.data(), XTS_SECTOR_SIZE, sector.data(), index, XTS_SECTOR_SIZE,
|
|
Op::Decrypt);
|
|
|
|
const std::size_t local_offset = (s == 0) ? sector_offset : 0;
|
|
const std::size_t available = XTS_SECTOR_SIZE - local_offset;
|
|
const std::size_t to_copy = std::min<std::size_t>(available, remaining);
|
|
std::memcpy(out, sector.data() + local_offset, to_copy);
|
|
|
|
out += to_copy;
|
|
current_offset += to_copy;
|
|
remaining -= to_copy;
|
|
total_read += to_copy;
|
|
}
|
|
}
|
|
|
|
return total_read;
|
|
}
|
|
} // namespace Core::Crypto
|