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file_sys: Add BKTR patching mechanism

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This commit is contained in:
Zach Hilman
2018-08-25 19:03:03 -04:00
parent 1efe5a76b1
commit 54e7ddb93a
2 changed files with 352 additions and 0 deletions
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208
src/core/file_sys/nca_patch.cpp Normal file
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// Copyright 2018 yuzu emulator team
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include "common/assert.h"
#include "core/crypto/aes_util.h"
#include "core/file_sys/nca_patch.h"
namespace FileSys {
BKTR::BKTR(VirtualFile base_romfs_, VirtualFile bktr_romfs_, RelocationBlock relocation_,
std::vector<RelocationBucket> relocation_buckets_, SubsectionBlock subsection_,
std::vector<SubsectionBucket> subsection_buckets_, bool is_encrypted_,
Core::Crypto::Key128 key_, u64 base_offset_, u64 ivfc_offset_,
std::array<u8, 8> section_ctr_)
: base_romfs(std::move(base_romfs_)), bktr_romfs(std::move(bktr_romfs_)),
relocation(relocation_), relocation_buckets(std::move(relocation_buckets_)),
subsection(subsection_), subsection_buckets(std::move(subsection_buckets_)),
encrypted(is_encrypted_), key(key_), base_offset(base_offset_), ivfc_offset(ivfc_offset_),
section_ctr(std::move(section_ctr_)) {
for (size_t i = 0; i < relocation.number_buckets - 1; ++i) {
relocation_buckets[i].entries.push_back({relocation.base_offsets[i + 1], 0, 0});
}
for (size_t i = 0; i < subsection.number_buckets - 1; ++i) {
subsection_buckets[i].entries.push_back({subsection_buckets[i + 1].entries[0].address_patch,
{0},
subsection_buckets[i + 1].entries[0].ctr});
}
relocation_buckets.back().entries.push_back({relocation.size, 0, 0});
}
size_t BKTR::Read(u8* data, size_t length, size_t offset) const {
// Read out of bounds.
if (offset >= relocation.size)
return 0;
const auto relocation = GetRelocationEntry(offset);
const auto section_offset = offset - relocation.address_patch + relocation.address_source;
const auto bktr_read = relocation.from_patch;
const auto next_relocation = GetNextRelocationEntry(offset);
if (offset + length <= next_relocation.address_patch) {
if (bktr_read) {
if (!encrypted) {
return bktr_romfs->Read(data, length, section_offset);
}
const auto subsection = GetSubsectionEntry(section_offset);
Core::Crypto::AESCipher<Core::Crypto::Key128> cipher(key, Core::Crypto::Mode::CTR);
// Calculate AES IV
std::vector<u8> iv(16);
auto subsection_ctr = subsection.ctr;
auto offset_iv = section_offset + base_offset;
for (u8 i = 0; i < 8; ++i)
iv[i] = section_ctr[0x8 - i - 1];
offset_iv >>= 4;
for (size_t i = 0; i < 8; ++i) {
iv[0xF - i] = static_cast<u8>(offset_iv & 0xFF);
offset_iv >>= 8;
}
for (size_t i = 0; i < 4; ++i) {
iv[0x7 - i] = static_cast<u8>(subsection_ctr & 0xFF);
subsection_ctr >>= 8;
}
cipher.SetIV(iv);
const auto next_subsection = GetNextSubsectionEntry(section_offset);
if (section_offset + length <= next_subsection.address_patch) {
const auto block_offset = section_offset & 0xF;
if (block_offset != 0) {
auto block = bktr_romfs->ReadBytes(0x10, section_offset & ~0xF);
cipher.Transcode(block.data(), block.size(), block.data(),
Core::Crypto::Op::Decrypt);
if (length + block_offset < 0x10) {
std::memcpy(data, block.data() + block_offset,
std::min(length, block.size()));
return std::min(length, block.size());
}
const auto read = 0x10 - block_offset;
std::memcpy(data, block.data() + block_offset, read);
return read + Read(data + read, length - read, offset + read);
}
const auto raw_read = bktr_romfs->Read(data, length, section_offset);
cipher.Transcode(data, raw_read, data, Core::Crypto::Op::Decrypt);
return raw_read;
} else {
const u64 partition = next_subsection.address_patch - section_offset;
return Read(data, partition, offset) +
Read(data + partition, length - partition, offset + partition);
}
} else {
ASSERT(section_offset > ivfc_offset, "Offset calculation negative.");
return base_romfs->Read(data, length, section_offset);
}
} else {
const u64 partition = next_relocation.address_patch - offset;
return Read(data, partition, offset) +
Read(data + partition, length - partition, offset + partition);
}
}
template <bool Subsection, typename BlockType, typename BucketType>
std::pair<size_t, size_t> BKTR::SearchBucketEntry(u64 offset, BlockType block,
BucketType buckets) const {
if constexpr (Subsection) {
const auto last_bucket = buckets[block.number_buckets - 1];
if (offset >= last_bucket.entries[last_bucket.number_entries].address_patch)
return {block.number_buckets - 1, last_bucket.number_entries};
} else {
ASSERT_MSG(offset <= block.size, "Offset is out of bounds in BKTR relocation block.");
}
size_t bucket_id = 0;
for (size_t i = 1; i < block.number_buckets; ++i) {
if (block.base_offsets[i] <= offset)
++bucket_id;
}
const auto bucket = buckets[bucket_id];
if (bucket.number_entries == 1)
return {bucket_id, 0};
size_t low = 0;
size_t mid = 0;
size_t high = bucket.number_entries - 1;
while (low <= high) {
mid = (low + high) / 2;
if (bucket.entries[mid].address_patch > offset) {
high = mid - 1;
} else {
if (mid == bucket.number_entries - 1 ||
bucket.entries[mid + 1].address_patch > offset) {
return {bucket_id, mid};
}
low = mid + 1;
}
}
UNREACHABLE_MSG("Offset could not be found in BKTR block.");
}
RelocationEntry BKTR::GetRelocationEntry(u64 offset) const {
const auto res = SearchBucketEntry<false>(offset, relocation, relocation_buckets);
return relocation_buckets[res.first].entries[res.second];
}
RelocationEntry BKTR::GetNextRelocationEntry(u64 offset) const {
const auto res = SearchBucketEntry<false>(offset, relocation, relocation_buckets);
const auto bucket = relocation_buckets[res.first];
if (res.second + 1 < bucket.entries.size())
return bucket.entries[res.second + 1];
return relocation_buckets[res.first + 1].entries[0];
}
SubsectionEntry BKTR::GetSubsectionEntry(u64 offset) const {
const auto res = SearchBucketEntry<true>(offset, subsection, subsection_buckets);
return subsection_buckets[res.first].entries[res.second];
}
SubsectionEntry BKTR::GetNextSubsectionEntry(u64 offset) const {
const auto res = SearchBucketEntry<true>(offset, subsection, subsection_buckets);
const auto bucket = subsection_buckets[res.first];
if (res.second + 1 < bucket.entries.size())
return bucket.entries[res.second + 1];
return subsection_buckets[res.first + 1].entries[0];
}
std::string BKTR::GetName() const {
return base_romfs->GetName();
}
size_t BKTR::GetSize() const {
return relocation.size;
}
bool BKTR::Resize(size_t new_size) {
return false;
}
std::shared_ptr<VfsDirectory> BKTR::GetContainingDirectory() const {
return base_romfs->GetContainingDirectory();
}
bool BKTR::IsWritable() const {
return false;
}
bool BKTR::IsReadable() const {
return true;
}
size_t BKTR::Write(const u8* data, size_t length, size_t offset) {
return 0;
}
bool BKTR::Rename(std::string_view name) {
return base_romfs->Rename(name);
}
} // namespace FileSys

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src/core/file_sys/nca_patch.h Normal file
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// Copyright 2018 yuzu emulator team
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#pragma once
#include "core/crypto/key_manager.h"
#include "core/file_sys/romfs.h"
#include "core/loader/loader.h"
namespace FileSys {
#pragma pack(push, 1)
struct RelocationEntry {
u64_le address_patch;
u64_le address_source;
u32 from_patch;
};
#pragma pack(pop)
static_assert(sizeof(RelocationEntry) == 0x14, "RelocationEntry has incorrect size.");
struct RelocationBucketRaw {
INSERT_PADDING_BYTES(4);
u32_le number_entries;
u64_le end_offset;
std::array<RelocationEntry, 0x332> relocation_entries;
INSERT_PADDING_BYTES(8);
};
static_assert(sizeof(RelocationBucketRaw) == 0x4000, "RelocationBucketRaw has incorrect size.");
// Vector version of RelocationBucketRaw
struct RelocationBucket {
u32 number_entries;
u64 end_offset;
std::vector<RelocationEntry> entries;
};
struct RelocationBlock {
INSERT_PADDING_BYTES(4);
u32_le number_buckets;
u64_le size;
std::array<u64, 0x7FE> base_offsets;
};
static_assert(sizeof(RelocationBlock) == 0x4000, "RelocationBlock has incorrect size.");
struct SubsectionEntry {
u64_le address_patch;
INSERT_PADDING_BYTES(0x4);
u32_le ctr;
};
static_assert(sizeof(SubsectionEntry) == 0x10, "SubsectionEntry has incorrect size.");
struct SubsectionBucketRaw {
INSERT_PADDING_BYTES(4);
u32_le number_entries;
u64_le end_offset;
std::array<SubsectionEntry, 0x3FF> subsection_entries;
};
static_assert(sizeof(SubsectionBucketRaw) == 0x4000, "SubsectionBucketRaw has incorrect size.");
// Vector version of SubsectionBucketRaw
struct SubsectionBucket {
u32 number_entries;
u64 end_offset;
std::vector<SubsectionEntry> entries;
};
struct SubsectionBlock {
INSERT_PADDING_BYTES(4);
u32_le number_buckets;
u64_le size;
std::array<u64, 0x7FE> base_offsets;
};
static_assert(sizeof(SubsectionBlock) == 0x4000, "SubsectionBlock has incorrect size.");
inline RelocationBucket ConvertRelocationBucketRaw(RelocationBucketRaw raw) {
return {raw.number_entries,
raw.end_offset,
{raw.relocation_entries.begin(), raw.relocation_entries.begin() + raw.number_entries}};
}
inline SubsectionBucket ConvertSubsectionBucketRaw(SubsectionBucketRaw raw) {
return {raw.number_entries,
raw.end_offset,
{raw.subsection_entries.begin(), raw.subsection_entries.begin() + raw.number_entries}};
}
class BKTR : public VfsFile {
public:
BKTR(VirtualFile base_romfs, VirtualFile bktr_romfs, RelocationBlock relocation,
std::vector<RelocationBucket> relocation_buckets, SubsectionBlock subsection,
std::vector<SubsectionBucket> subsection_buckets, bool is_encrypted,
Core::Crypto::Key128 key, u64 base_offset, u64 ivfc_offset, std::array<u8, 8> section_ctr);
size_t Read(u8* data, size_t length, size_t offset) const override;
std::string GetName() const override;
size_t GetSize() const override;
bool Resize(size_t new_size) override;
std::shared_ptr<VfsDirectory> GetContainingDirectory() const override;
bool IsWritable() const override;
bool IsReadable() const override;
size_t Write(const u8* data, size_t length, size_t offset) override;
bool Rename(std::string_view name) override;
private:
template <bool Subsection, typename BlockType, typename BucketType>
std::pair<size_t, size_t> SearchBucketEntry(u64 offset, BlockType block,
BucketType buckets) const;
RelocationEntry GetRelocationEntry(u64 offset) const;
RelocationEntry GetNextRelocationEntry(u64 offset) const;
SubsectionEntry GetSubsectionEntry(u64 offset) const;
SubsectionEntry GetNextSubsectionEntry(u64 offset) const;
RelocationBlock relocation;
std::vector<RelocationBucket> relocation_buckets;
SubsectionBlock subsection;
std::vector<SubsectionBucket> subsection_buckets;
// Should be the raw base romfs, decrypted.
VirtualFile base_romfs;
// Should be the raw BKTR romfs, (located at media_offset with size media_size).
VirtualFile bktr_romfs;
bool encrypted;
Core::Crypto::Key128 key;
// Base offset into NCA, used for IV calculation.
u64 base_offset;
// Distance between IVFC start and RomFS start, used for base reads
u64 ivfc_offset;
std::array<u8, 8> section_ctr;
};
} // namespace FileSys