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// SPDX-License-Identifier: GPL-3.0-or-later | ||
// Copyright © 2023 Strato Team and Contributors (https://github.com/strato-emu/) | ||
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#include "bktr.h" | ||
#include "region_backing.h" | ||
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namespace skyline::vfs { | ||
template <typename BlockType, typename BucketType> | ||
std::pair<u64, u64> SearchBucketEntry(u64 offset, const BlockType &block, const BucketType &buckets, bool isSubsection) { | ||
if (isSubsection) { | ||
const auto &lastBucket{buckets[block.numberBuckets - 1]}; | ||
if (offset >= lastBucket.entries[lastBucket.numberEntries].addressPatch) { | ||
return {block.numberBuckets - 1, lastBucket.numberEntries}; | ||
} | ||
} | ||
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u64 bucketId{static_cast<u64>(std::distance(block.baseOffsets.begin(), | ||
std::upper_bound(block.baseOffsets.begin() + 1, | ||
block.baseOffsets.begin() + block.numberBuckets, offset)) - 1)}; | ||
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const auto &bucket{buckets[bucketId]}; | ||
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if (bucket.numberEntries == 1) | ||
return {bucketId, 0}; | ||
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auto entryIt{std::upper_bound(bucket.entries.begin(), bucket.entries.begin() + bucket.numberEntries, offset, [](u64 offset, const auto& entry) { | ||
return offset < entry.addressPatch; | ||
})}; | ||
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if (entryIt != bucket.entries.begin()) { | ||
u64 entryIndex{static_cast<u64>(std::distance(bucket.entries.begin(), entryIt) - 1)}; | ||
return {bucketId, entryIndex}; | ||
} | ||
Logger::Error("Offset could not be found."); | ||
return {0, 0}; | ||
} | ||
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BKTR::BKTR(std::shared_ptr<vfs::Backing> pBaseRomfs, std::shared_ptr<vfs::Backing> pBktrRomfs, RelocationBlock pRelocation, | ||
std::vector<RelocationBucket> pRelocationBuckets, SubsectionBlock pSubsection, | ||
std::vector<SubsectionBucket> pSubsectionBuckets, bool pIsEncrypted, std::array<u8, 16> pKey, | ||
u64 pBaseOffset, u64 pIvfcOffset, std::array<u8, 8> pSectionCtr) | ||
: baseRomFs(std::move(pBaseRomfs)), bktrRomFs(std::move(pBktrRomfs)), | ||
relocation(pRelocation), relocationBuckets(std::move(pRelocationBuckets)), | ||
subsection(pSubsection), subsectionBuckets(std::move(pSubsectionBuckets)), | ||
isEncrypted(pIsEncrypted), key(pKey), baseOffset(pBaseOffset), ivfcOffset(pIvfcOffset), | ||
sectionCtr(pSectionCtr) { | ||
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for (std::size_t i = 0; i < relocation.numberBuckets - 1; ++i) | ||
relocationBuckets[i].entries.push_back({relocation.baseOffsets[i + 1], 0, 0}); | ||
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for (std::size_t i = 0; i < subsection.numberBuckets - 1; ++i) | ||
subsectionBuckets[i].entries.push_back({subsectionBuckets[i + 1].entries[0].addressPatch, {0}, subsectionBuckets[i + 1].entries[0].ctr}); | ||
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relocationBuckets.back().entries.push_back({relocation.size, 0, 0}); | ||
} | ||
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size_t BKTR::ReadImpl(span<u8> output, size_t offset) { | ||
if (offset >= relocation.size) | ||
return 0; | ||
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const auto relocationEntry{GetRelocationEntry(offset)}; | ||
const auto sectionOffset{offset - relocationEntry.addressPatch + relocationEntry.addressSource}; | ||
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const auto nextRelocation{GetNextRelocationEntry(offset)}; | ||
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if (offset + output.size() > nextRelocation.addressPatch) { | ||
const u64 partition{nextRelocation.addressPatch - offset}; | ||
span<u8> data(output.data() + partition, output.size() - partition); | ||
return ReadWithPartition(data, output.size() - partition, offset + partition) + ReadWithPartition(output, partition, offset); | ||
} | ||
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if (!relocationEntry.fromPatch) { | ||
auto regionBacking{std::make_shared<RegionBacking>(baseRomFs, sectionOffset - ivfcOffset, output.size())}; | ||
return regionBacking->Read(output); | ||
} | ||
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if (!isEncrypted) | ||
return bktrRomFs->Read(output, sectionOffset); | ||
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const auto subsectionEntry{GetSubsectionEntry(sectionOffset)}; | ||
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crypto::AesCipher cipher(key, MBEDTLS_CIPHER_AES_128_CTR); | ||
cipher.SetIV(GetCipherIV(subsectionEntry, sectionOffset)); | ||
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const auto nextSubsection{GetNextSubsectionEntry(sectionOffset)}; | ||
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if (sectionOffset + output.size() > nextSubsection.addressPatch) { | ||
const u64 partition{nextSubsection.addressPatch - sectionOffset}; | ||
span<u8> data(output.data() + partition, output.size() - partition); | ||
return ReadWithPartition(data, output.size() - partition, offset + partition) + | ||
ReadWithPartition(output, partition, offset); | ||
} | ||
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const auto blockOffset{sectionOffset & 0xF}; | ||
if (blockOffset != 0) { | ||
std::vector<u8> block(0x10); | ||
auto regionBacking{std::make_shared<RegionBacking>(bktrRomFs, sectionOffset & static_cast<u32>(~0xF), 0x10)}; | ||
regionBacking->Read(block); | ||
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cipher.Decrypt(block.data(), block.data(), block.size()); | ||
if (output.size() + blockOffset < 0x10) { | ||
std::memcpy(output.data(), block.data() + blockOffset, std::min(output.size(), block.size())); | ||
return std::min(output.size(), block.size()); | ||
} | ||
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const auto read{0x10 - blockOffset}; | ||
std::memcpy(output.data(), block.data() + blockOffset, read); | ||
span<u8> data(output.data() + read, output.size() - read); | ||
return read + ReadWithPartition(data, output.size() - read, offset + read); | ||
} | ||
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auto regionBacking{std::make_shared<RegionBacking>(bktrRomFs, sectionOffset, output.size())}; | ||
auto readSize{regionBacking->Read(output)}; | ||
cipher.Decrypt(output.data(), output.data(), readSize); | ||
return readSize; | ||
} | ||
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size_t BKTR::ReadWithPartition(span<u8> output, size_t length, size_t offset) { | ||
if (offset >= relocation.size) | ||
return 0; | ||
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const auto relocationEntry{GetRelocationEntry(offset)}; | ||
const auto sectionOffset{offset - relocationEntry.addressPatch + relocationEntry.addressSource}; | ||
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const auto nextRelocation{GetNextRelocationEntry(offset)}; | ||
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if (offset + length > nextRelocation.addressPatch) { | ||
const u64 partition{nextRelocation.addressPatch - offset}; | ||
span<u8> data(output.data() + partition, length - partition); | ||
return ReadWithPartition(data, length - partition, offset + partition) + ReadWithPartition(output, partition, offset); | ||
} | ||
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if (!relocationEntry.fromPatch) { | ||
span<u8> data(output.data(), length); | ||
auto regionBacking{std::make_shared<RegionBacking>(baseRomFs, sectionOffset - ivfcOffset, length)}; | ||
return regionBacking->Read(data); | ||
} | ||
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if (!isEncrypted) | ||
return bktrRomFs->Read(output, sectionOffset); | ||
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const auto subsectionEntry{GetSubsectionEntry(sectionOffset)}; | ||
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crypto::AesCipher cipher(key, MBEDTLS_CIPHER_AES_128_CTR); | ||
cipher.SetIV(GetCipherIV(subsectionEntry, sectionOffset)); | ||
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const auto nextSubsection{GetNextSubsectionEntry(sectionOffset)}; | ||
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if (sectionOffset + length > nextSubsection.addressPatch) { | ||
const u64 partition{nextSubsection.addressPatch - sectionOffset}; | ||
span<u8> data(output.data() + partition, length - partition); | ||
return ReadWithPartition(data, length - partition, offset + partition) + | ||
ReadWithPartition(output, partition, offset); | ||
} | ||
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const auto blockOffset{sectionOffset & 0xF}; | ||
if (blockOffset != 0) { | ||
std::vector<u8> block(0x10); | ||
auto regionBacking{std::make_shared<RegionBacking>(bktrRomFs, sectionOffset & static_cast<u32>(~0xF), 0x10)}; | ||
regionBacking->Read(block); | ||
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cipher.Decrypt(block.data(), block.data(), block.size()); | ||
if (length + blockOffset < 0x10) { | ||
std::memcpy(output.data(), block.data() + blockOffset, std::min(length, block.size())); | ||
return std::min(length, block.size()); | ||
} | ||
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const auto read{0x10 - blockOffset}; | ||
std::memcpy(output.data(), block.data() + blockOffset, read); | ||
span<u8> data(output.data() + read, length - read); | ||
return read + ReadWithPartition(data, length - read, offset + read); | ||
} | ||
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auto regionBacking{std::make_shared<RegionBacking>(bktrRomFs, sectionOffset, length)}; | ||
span<u8> data(output.data(), length); | ||
size_t readSize{0}; | ||
if (length) | ||
readSize = regionBacking->Read(data); | ||
cipher.Decrypt(data.data(), data.data(), readSize); | ||
return readSize; | ||
} | ||
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SubsectionEntry BKTR::GetNextSubsectionEntry(u64 offset) { | ||
const auto entry{SearchBucketEntry(offset, subsection, subsectionBuckets, true)}; | ||
const auto bucket{subsectionBuckets[entry.first]}; | ||
if (entry.second + 1 < bucket.entries.size()) | ||
return bucket.entries[entry.second + 1]; | ||
return subsectionBuckets[entry.first + 1].entries[0]; | ||
} | ||
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RelocationEntry BKTR::GetRelocationEntry(u64 offset) { | ||
const auto entry{SearchBucketEntry(offset, relocation, relocationBuckets, false)}; | ||
return relocationBuckets[entry.first].entries[entry.second]; | ||
} | ||
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SubsectionEntry BKTR::GetSubsectionEntry(u64 offset) { | ||
const auto entry{SearchBucketEntry(offset, subsection, subsectionBuckets, true)}; | ||
return subsectionBuckets[entry.first].entries[entry.second]; | ||
} | ||
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RelocationEntry BKTR::GetNextRelocationEntry(u64 offset) { | ||
const auto entry{SearchBucketEntry(offset, relocation, relocationBuckets, false)}; | ||
const auto bucket{relocationBuckets[entry.first]}; | ||
if (entry.second + 1 < bucket.entries.size()) | ||
return bucket.entries[entry.second + 1]; | ||
return relocationBuckets[entry.first + 1].entries[0]; | ||
} | ||
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std::array<u8, 16> BKTR::GetCipherIV(SubsectionEntry subsectionEntry, u64 sectionOffset) { | ||
std::array<u8, 16> iv{}; | ||
auto subsectionCtr{subsectionEntry.ctr}; | ||
auto offset_iv{sectionOffset + baseOffset}; | ||
for (std::size_t i = 0; i < sectionCtr.size(); ++i) { | ||
iv[i] = sectionCtr[0x8 - i - 1]; | ||
} | ||
offset_iv >>= 4; | ||
for (std::size_t i = 0; i < sizeof(u64); ++i) { | ||
iv[0xF - i] = static_cast<u8>(offset_iv & 0xFF); | ||
offset_iv >>= 8; | ||
} | ||
for (std::size_t i = 0; i < sizeof(u32); ++i) { | ||
iv[0x7 - i] = static_cast<u8>(subsectionCtr & 0xFF); | ||
subsectionCtr >>= 8; | ||
} | ||
return iv; | ||
} | ||
} |
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@@ -0,0 +1,49 @@ | ||
// SPDX-License-Identifier: GPL-3.0-or-later | ||
// Copyright © 2023 Strato Team and Contributors (https://github.com/strato-emu/) | ||
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#pragma once | ||
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#include "filesystem.h" | ||
#include "nca.h" | ||
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namespace skyline::vfs { | ||
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/** | ||
* @brief Allows reading patched RomFs | ||
* @url https://switchbrew.org/wiki/NCA#RomFs_Patching | ||
*/ | ||
class BKTR : public Backing { | ||
private: | ||
std::shared_ptr<vfs::Backing> baseRomFs; | ||
std::shared_ptr<vfs::Backing> bktrRomFs; | ||
RelocationBlock relocation; | ||
SubsectionBlock subsection; | ||
std::vector<RelocationBucket> relocationBuckets; | ||
std::vector<SubsectionBucket> subsectionBuckets; | ||
bool isEncrypted; | ||
u64 baseOffset; | ||
u64 ivfcOffset; | ||
std::array<u8, 8> sectionCtr; | ||
std::array<u8, 16> key; | ||
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SubsectionEntry GetNextSubsectionEntry(u64 offset); | ||
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RelocationEntry GetRelocationEntry(u64 offset); | ||
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RelocationEntry GetNextRelocationEntry(u64 offset); | ||
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SubsectionEntry GetSubsectionEntry(u64 offset); | ||
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std::array<u8, 16> GetCipherIV(SubsectionEntry subsectionEntry, u64 sectionOffset); | ||
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public: | ||
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BKTR(std::shared_ptr<vfs::Backing> pBaseRomfs, std::shared_ptr<vfs::Backing> pBktrRomfs, RelocationBlock pRelocation, | ||
std::vector<RelocationBucket> pRelocationBuckets, SubsectionBlock pSubsection, | ||
std::vector<SubsectionBucket> pSubsectionBuckets, bool pIsEncrypted, std::array<u8, 16> pKey, | ||
u64 pBaseOffset, u64 pIvfcOffset, std::array<u8, 8> pSectionCtr); | ||
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size_t ReadImpl(span<u8> output, size_t offset) override; | ||
size_t ReadWithPartition(span<u8> output, size_t length, size_t offset); | ||
}; | ||
} |