211 lines
7.6 KiB
C++
211 lines
7.6 KiB
C++
// Copyright 2018 yuzu emulator team
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// Licensed under GPLv2 or any later version
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// Refer to the license.txt file included.
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#include <algorithm>
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#include <cstddef>
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#include <cstring>
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#include "common/assert.h"
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#include "core/crypto/aes_util.h"
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#include "core/file_sys/nca_patch.h"
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namespace FileSys {
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BKTR::BKTR(VirtualFile base_romfs_, VirtualFile bktr_romfs_, RelocationBlock relocation_,
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std::vector<RelocationBucket> relocation_buckets_, SubsectionBlock subsection_,
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std::vector<SubsectionBucket> subsection_buckets_, bool is_encrypted_,
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Core::Crypto::Key128 key_, u64 base_offset_, u64 ivfc_offset_,
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std::array<u8, 8> section_ctr_)
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: relocation(relocation_), relocation_buckets(std::move(relocation_buckets_)),
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subsection(subsection_), subsection_buckets(std::move(subsection_buckets_)),
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base_romfs(std::move(base_romfs_)), bktr_romfs(std::move(bktr_romfs_)),
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encrypted(is_encrypted_), key(key_), base_offset(base_offset_), ivfc_offset(ivfc_offset_),
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section_ctr(section_ctr_) {
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for (std::size_t i = 0; i < relocation.number_buckets - 1; ++i) {
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relocation_buckets[i].entries.push_back({relocation.base_offsets[i + 1], 0, 0});
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}
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for (std::size_t i = 0; i < subsection.number_buckets - 1; ++i) {
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subsection_buckets[i].entries.push_back({subsection_buckets[i + 1].entries[0].address_patch,
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{0},
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subsection_buckets[i + 1].entries[0].ctr});
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}
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relocation_buckets.back().entries.push_back({relocation.size, 0, 0});
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}
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BKTR::~BKTR() = default;
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std::size_t BKTR::Read(u8* data, std::size_t length, std::size_t offset) const {
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// Read out of bounds.
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if (offset >= relocation.size)
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return 0;
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const auto relocation = GetRelocationEntry(offset);
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const auto section_offset = offset - relocation.address_patch + relocation.address_source;
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const auto bktr_read = relocation.from_patch;
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const auto next_relocation = GetNextRelocationEntry(offset);
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if (offset + length > next_relocation.address_patch) {
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const u64 partition = next_relocation.address_patch - offset;
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return Read(data, partition, offset) +
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Read(data + partition, length - partition, offset + partition);
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}
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if (!bktr_read) {
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ASSERT_MSG(section_offset >= ivfc_offset, "Offset calculation negative.");
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return base_romfs->Read(data, length, section_offset - ivfc_offset);
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}
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if (!encrypted) {
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return bktr_romfs->Read(data, length, section_offset);
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}
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const auto subsection = GetSubsectionEntry(section_offset);
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Core::Crypto::AESCipher<Core::Crypto::Key128> cipher(key, Core::Crypto::Mode::CTR);
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// Calculate AES IV
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std::vector<u8> iv(16);
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auto subsection_ctr = subsection.ctr;
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auto offset_iv = section_offset + base_offset;
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for (std::size_t i = 0; i < section_ctr.size(); ++i)
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iv[i] = section_ctr[0x8 - i - 1];
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offset_iv >>= 4;
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for (std::size_t i = 0; i < sizeof(u64); ++i) {
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iv[0xF - i] = static_cast<u8>(offset_iv & 0xFF);
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offset_iv >>= 8;
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}
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for (std::size_t i = 0; i < sizeof(u32); ++i) {
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iv[0x7 - i] = static_cast<u8>(subsection_ctr & 0xFF);
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subsection_ctr >>= 8;
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}
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cipher.SetIV(iv);
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const auto next_subsection = GetNextSubsectionEntry(section_offset);
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if (section_offset + length > next_subsection.address_patch) {
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const u64 partition = next_subsection.address_patch - section_offset;
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return Read(data, partition, offset) +
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Read(data + partition, length - partition, offset + partition);
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}
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const auto block_offset = section_offset & 0xF;
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if (block_offset != 0) {
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auto block = bktr_romfs->ReadBytes(0x10, section_offset & ~0xF);
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cipher.Transcode(block.data(), block.size(), block.data(), Core::Crypto::Op::Decrypt);
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if (length + block_offset < 0x10) {
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std::memcpy(data, block.data() + block_offset, std::min(length, block.size()));
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return std::min(length, block.size());
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}
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const auto read = 0x10 - block_offset;
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std::memcpy(data, block.data() + block_offset, read);
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return read + Read(data + read, length - read, offset + read);
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}
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const auto raw_read = bktr_romfs->Read(data, length, section_offset);
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cipher.Transcode(data, raw_read, data, Core::Crypto::Op::Decrypt);
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return raw_read;
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}
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template <bool Subsection, typename BlockType, typename BucketType>
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std::pair<std::size_t, std::size_t> BKTR::SearchBucketEntry(u64 offset, BlockType block,
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BucketType buckets) const {
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if constexpr (Subsection) {
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const auto last_bucket = buckets[block.number_buckets - 1];
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if (offset >= last_bucket.entries[last_bucket.number_entries].address_patch)
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return {block.number_buckets - 1, last_bucket.number_entries};
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} else {
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ASSERT_MSG(offset <= block.size, "Offset is out of bounds in BKTR relocation block.");
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}
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std::size_t bucket_id = std::count_if(
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block.base_offsets.begin() + 1, block.base_offsets.begin() + block.number_buckets,
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[&offset](u64 base_offset) { return base_offset <= offset; });
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const auto bucket = buckets[bucket_id];
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if (bucket.number_entries == 1)
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return {bucket_id, 0};
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std::size_t low = 0;
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std::size_t mid = 0;
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std::size_t high = bucket.number_entries - 1;
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while (low <= high) {
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mid = (low + high) / 2;
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if (bucket.entries[mid].address_patch > offset) {
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high = mid - 1;
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} else {
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if (mid == bucket.number_entries - 1 ||
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bucket.entries[mid + 1].address_patch > offset) {
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return {bucket_id, mid};
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}
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low = mid + 1;
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}
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}
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UNREACHABLE_MSG("Offset could not be found in BKTR block.");
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}
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RelocationEntry BKTR::GetRelocationEntry(u64 offset) const {
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const auto res = SearchBucketEntry<false>(offset, relocation, relocation_buckets);
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return relocation_buckets[res.first].entries[res.second];
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}
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RelocationEntry BKTR::GetNextRelocationEntry(u64 offset) const {
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const auto res = SearchBucketEntry<false>(offset, relocation, relocation_buckets);
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const auto bucket = relocation_buckets[res.first];
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if (res.second + 1 < bucket.entries.size())
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return bucket.entries[res.second + 1];
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return relocation_buckets[res.first + 1].entries[0];
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}
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SubsectionEntry BKTR::GetSubsectionEntry(u64 offset) const {
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const auto res = SearchBucketEntry<true>(offset, subsection, subsection_buckets);
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return subsection_buckets[res.first].entries[res.second];
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}
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SubsectionEntry BKTR::GetNextSubsectionEntry(u64 offset) const {
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const auto res = SearchBucketEntry<true>(offset, subsection, subsection_buckets);
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const auto bucket = subsection_buckets[res.first];
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if (res.second + 1 < bucket.entries.size())
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return bucket.entries[res.second + 1];
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return subsection_buckets[res.first + 1].entries[0];
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}
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std::string BKTR::GetName() const {
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return base_romfs->GetName();
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}
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std::size_t BKTR::GetSize() const {
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return relocation.size;
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}
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bool BKTR::Resize(std::size_t new_size) {
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return false;
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}
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std::shared_ptr<VfsDirectory> BKTR::GetContainingDirectory() const {
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return base_romfs->GetContainingDirectory();
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}
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bool BKTR::IsWritable() const {
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return false;
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}
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bool BKTR::IsReadable() const {
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return true;
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}
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std::size_t BKTR::Write(const u8* data, std::size_t length, std::size_t offset) {
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return 0;
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}
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bool BKTR::Rename(std::string_view name) {
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return base_romfs->Rename(name);
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}
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} // namespace FileSys
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