// Copyright 2018 yuzu emulator team
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <algorithm>
#include <utility>
#include <boost/optional.hpp>
#include "common/logging/log.h"
#include "core/crypto/aes_util.h"
#include "core/crypto/ctr_encryption_layer.h"
#include "core/file_sys/content_archive.h"
#include "core/file_sys/romfs.h"
#include "core/file_sys/vfs_offset.h"
#include "core/loader/loader.h"
namespace FileSys {
// Media offsets in headers are stored divided by 512. Mult. by this to get real offset.
constexpr u64 MEDIA_OFFSET_MULTIPLIER = 0x200;
constexpr u64 SECTION_HEADER_SIZE = 0x200;
constexpr u64 SECTION_HEADER_OFFSET = 0x400;
constexpr u32 IVFC_MAX_LEVEL = 6;
enum class NCASectionFilesystemType : u8 {
PFS0 = 0x2,
ROMFS = 0x3,
};
struct NCASectionHeaderBlock {
INSERT_PADDING_BYTES(3);
NCASectionFilesystemType filesystem_type;
NCASectionCryptoType crypto_type;
INSERT_PADDING_BYTES(3);
};
static_assert(sizeof(NCASectionHeaderBlock) == 0x8, "NCASectionHeaderBlock has incorrect size.");
struct NCASectionRaw {
NCASectionHeaderBlock header;
std::array<u8, 0x138> block_data;
std::array<u8, 0x8> section_ctr;
INSERT_PADDING_BYTES(0xB8);
};
static_assert(sizeof(NCASectionRaw) == 0x200, "NCASectionRaw has incorrect size.");
struct PFS0Superblock {
NCASectionHeaderBlock header_block;
std::array<u8, 0x20> hash;
u32_le size;
INSERT_PADDING_BYTES(4);
u64_le hash_table_offset;
u64_le hash_table_size;
u64_le pfs0_header_offset;
u64_le pfs0_size;
INSERT_PADDING_BYTES(0x1B0);
};
static_assert(sizeof(PFS0Superblock) == 0x200, "PFS0Superblock has incorrect size.");
struct RomFSSuperblock {
NCASectionHeaderBlock header_block;
IVFCHeader ivfc;
INSERT_PADDING_BYTES(0x118);
};
static_assert(sizeof(RomFSSuperblock) == 0x200, "RomFSSuperblock has incorrect size.");
union NCASectionHeader {
NCASectionRaw raw;
PFS0Superblock pfs0;
RomFSSuperblock romfs;
};
static_assert(sizeof(NCASectionHeader) == 0x200, "NCASectionHeader has incorrect size.");
bool IsValidNCA(const NCAHeader& header) {
// TODO(DarkLordZach): Add NCA2/NCA0 support.
return header.magic == Common::MakeMagic('N', 'C', 'A', '3');
}
boost::optional<Core::Crypto::Key128> NCA::GetKeyAreaKey(NCASectionCryptoType type) const {
u8 master_key_id = header.crypto_type;
if (header.crypto_type_2 > master_key_id)
master_key_id = header.crypto_type_2;
if (master_key_id > 0)
--master_key_id;
if (!keys.HasKey(Core::Crypto::S128KeyType::KeyArea, master_key_id, header.key_index))
return boost::none;
std::vector<u8> key_area(header.key_area.begin(), header.key_area.end());
Core::Crypto::AESCipher<Core::Crypto::Key128> cipher(
keys.GetKey(Core::Crypto::S128KeyType::KeyArea, master_key_id, header.key_index),
Core::Crypto::Mode::ECB);
cipher.Transcode(key_area.data(), key_area.size(), key_area.data(), Core::Crypto::Op::Decrypt);
Core::Crypto::Key128 out;
if (type == NCASectionCryptoType::XTS)
std::copy(key_area.begin(), key_area.begin() + 0x10, out.begin());
else if (type == NCASectionCryptoType::CTR)
std::copy(key_area.begin() + 0x20, key_area.begin() + 0x30, out.begin());
else
LOG_CRITICAL(Crypto, "Called GetKeyAreaKey on invalid NCASectionCryptoType type={:02X}",
static_cast<u8>(type));
u128 out_128{};
memcpy(out_128.data(), out.data(), 16);
LOG_DEBUG(Crypto, "called with crypto_rev={:02X}, kak_index={:02X}, key={:016X}{:016X}",
master_key_id, header.key_index, out_128[1], out_128[0]);
return out;
}
VirtualFile NCA::Decrypt(NCASectionHeader header, VirtualFile in, u64 starting_offset) const {
if (!encrypted)
return in;
switch (header.raw.header.crypto_type) {
case NCASectionCryptoType::NONE:
LOG_DEBUG(Crypto, "called with mode=NONE");
return in;
case NCASectionCryptoType::CTR:
LOG_DEBUG(Crypto, "called with mode=CTR, starting_offset={:016X}", starting_offset);
{
const auto key = GetKeyAreaKey(NCASectionCryptoType::CTR);
if (key == boost::none)
return nullptr;
auto out = std::make_shared<Core::Crypto::CTREncryptionLayer>(
std::move(in), key.value(), starting_offset);
std::vector<u8> iv(16);
for (u8 i = 0; i < 8; ++i)
iv[i] = header.raw.section_ctr[0x8 - i - 1];
out->SetIV(iv);
return std::static_pointer_cast<VfsFile>(out);
}
case NCASectionCryptoType::XTS:
// TODO(DarkLordZach): Implement XTSEncryptionLayer and title key encryption.
default:
LOG_ERROR(Crypto, "called with unhandled crypto type={:02X}",
static_cast<u8>(header.raw.header.crypto_type));
return nullptr;
}
}
NCA::NCA(VirtualFile file_) : file(std::move(file_)) {
if (sizeof(NCAHeader) != file->ReadObject(&header))
LOG_ERROR(Loader, "File reader errored out during header read.");
encrypted = false;
if (!IsValidNCA(header)) {
NCAHeader dec_header{};
Core::Crypto::AESCipher<Core::Crypto::Key256> cipher(
keys.GetKey(Core::Crypto::S256KeyType::Header), Core::Crypto::Mode::XTS);
cipher.XTSTranscode(&header, sizeof(NCAHeader), &dec_header, 0, 0x200,
Core::Crypto::Op::Decrypt);
if (IsValidNCA(dec_header)) {
header = dec_header;
encrypted = true;
} else {
if (!keys.HasKey(Core::Crypto::S256KeyType::Header))
status = Loader::ResultStatus::ErrorMissingKeys;
else
status = Loader::ResultStatus::ErrorDecrypting;
return;
}
}
const std::ptrdiff_t number_sections =
std::count_if(std::begin(header.section_tables), std::end(header.section_tables),
[](NCASectionTableEntry entry) { return entry.media_offset > 0; });
std::vector<NCASectionHeader> sections(number_sections);
const auto length_sections = SECTION_HEADER_SIZE * number_sections;
if (encrypted) {
auto raw = file->ReadBytes(length_sections, SECTION_HEADER_OFFSET);
Core::Crypto::AESCipher<Core::Crypto::Key256> cipher(
keys.GetKey(Core::Crypto::S256KeyType::Header), Core::Crypto::Mode::XTS);
cipher.XTSTranscode(raw.data(), length_sections, sections.data(), 2, SECTION_HEADER_SIZE,
Core::Crypto::Op::Decrypt);
} else {
file->ReadBytes(sections.data(), length_sections, SECTION_HEADER_OFFSET);
}
for (std::ptrdiff_t i = 0; i < number_sections; ++i) {
auto section = sections[i];
if (section.raw.header.filesystem_type == NCASectionFilesystemType::ROMFS) {
const size_t romfs_offset =
header.section_tables[i].media_offset * MEDIA_OFFSET_MULTIPLIER +
section.romfs.ivfc.levels[IVFC_MAX_LEVEL - 1].offset;
const size_t romfs_size = section.romfs.ivfc.levels[IVFC_MAX_LEVEL - 1].size;
auto dec =
Decrypt(section, std::make_shared<OffsetVfsFile>(file, romfs_size, romfs_offset),
romfs_offset);
if (dec != nullptr) {
files.push_back(std::move(dec));
romfs = files.back();
} else {
status = Loader::ResultStatus::ErrorMissingKeys;
return;
}
} else if (section.raw.header.filesystem_type == NCASectionFilesystemType::PFS0) {
u64 offset = (static_cast<u64>(header.section_tables[i].media_offset) *
MEDIA_OFFSET_MULTIPLIER) +
section.pfs0.pfs0_header_offset;
u64 size = MEDIA_OFFSET_MULTIPLIER * (header.section_tables[i].media_end_offset -
header.section_tables[i].media_offset);
auto dec =
Decrypt(section, std::make_shared<OffsetVfsFile>(file, size, offset), offset);
if (dec != nullptr) {
auto npfs = std::make_shared<PartitionFilesystem>(std::move(dec));
if (npfs->GetStatus() == Loader::ResultStatus::Success) {
dirs.push_back(std::move(npfs));
if (IsDirectoryExeFS(dirs.back()))
exefs = dirs.back();
}
} else {
status = Loader::ResultStatus::ErrorMissingKeys;
return;
}
}
}
status = Loader::ResultStatus::Success;
}
Loader::ResultStatus NCA::GetStatus() const {
return status;
}
std::vector<std::shared_ptr<VfsFile>> NCA::GetFiles() const {
if (status != Loader::ResultStatus::Success)
return {};
return files;
}
std::vector<std::shared_ptr<VfsDirectory>> NCA::GetSubdirectories() const {
if (status != Loader::ResultStatus::Success)
return {};
return dirs;
}
std::string NCA::GetName() const {
return file->GetName();
}
std::shared_ptr<VfsDirectory> NCA::GetParentDirectory() const {
return file->GetContainingDirectory();
}
NCAContentType NCA::GetType() const {
return header.content_type;
}
u64 NCA::GetTitleId() const {
if (status != Loader::ResultStatus::Success)
return {};
return header.title_id;
}
VirtualFile NCA::GetRomFS() const {
return romfs;
}
VirtualDir NCA::GetExeFS() const {
return exefs;
}
VirtualFile NCA::GetBaseFile() const {
return file;
}
bool NCA::ReplaceFileWithSubdirectory(VirtualFile file, VirtualDir dir) {
return false;
}
} // namespace FileSys
