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	Load keys from new3DS native firm
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					 2 changed files with 170 additions and 11 deletions
				
			
		|  | @ -51,3 +51,4 @@ | |||
| #define SHARED_FONT "shared_font.bin" | ||||
| #define AES_KEYS "aes_keys.txt" | ||||
| #define BOOTROM9 "boot9.bin" | ||||
| #define SECRET_SECTOR "sector0x96.bin" | ||||
|  |  | |||
|  | @ -6,6 +6,8 @@ | |||
| #include <exception> | ||||
| #include <optional> | ||||
| #include <sstream> | ||||
| #include <cryptopp/aes.h> | ||||
| #include <cryptopp/modes.h> | ||||
| #include <fmt/format.h> | ||||
| #include "common/common_paths.h" | ||||
| #include "common/file_util.h" | ||||
|  | @ -37,6 +39,19 @@ struct KeyDesc { | |||
|     bool same_as_before; | ||||
| }; | ||||
| 
 | ||||
| AESKey HexToKey(const std::string& hex) { | ||||
|     if (hex.size() < 32) { | ||||
|         throw std::invalid_argument("hex string is too short"); | ||||
|     } | ||||
| 
 | ||||
|     AESKey key; | ||||
|     for (std::size_t i = 0; i < key.size(); ++i) { | ||||
|         key[i] = static_cast<u8>(std::stoi(hex.substr(i * 2, 2), 0, 16)); | ||||
|     } | ||||
| 
 | ||||
|     return key; | ||||
| } | ||||
| 
 | ||||
| struct KeySlot { | ||||
|     std::optional<AESKey> x; | ||||
|     std::optional<AESKey> y; | ||||
|  | @ -74,18 +89,39 @@ struct KeySlot { | |||
| std::array<KeySlot, KeySlotID::MaxKeySlotID> key_slots; | ||||
| std::array<std::optional<AESKey>, 6> common_key_y_slots; | ||||
| 
 | ||||
| AESKey HexToKey(const std::string& hex) { | ||||
|     if (hex.size() < 32) { | ||||
|         throw std::invalid_argument("hex string is too short"); | ||||
|     } | ||||
| enum class FirmwareType : u32 { | ||||
|     ARM9 = 0,  // uses NDMA
 | ||||
|     ARM11 = 1, // uses XDMA
 | ||||
| }; | ||||
| 
 | ||||
|     AESKey key; | ||||
|     for (std::size_t i = 0; i < key.size(); ++i) { | ||||
|         key[i] = static_cast<u8>(std::stoi(hex.substr(i * 2, 2), 0, 16)); | ||||
|     } | ||||
| struct FirmwareSectionHeader { | ||||
|     u32_le offset; | ||||
|     u32_le phys_address; | ||||
|     u32_le size; | ||||
|     enum_le<FirmwareType> firmware_type; | ||||
|     std::array<u8, 0x20> hash; // SHA-256 hash
 | ||||
| }; | ||||
| 
 | ||||
|     return key; | ||||
| } | ||||
| struct FIRM_Header { | ||||
|     u32_le magic;         // FIRM
 | ||||
|     u32_le boot_priority; // Usually 0
 | ||||
|     u32_le arm11_entrypoint; | ||||
|     u32_le arm9_entrypoint; | ||||
|     INSERT_PADDING_BYTES(0x30);                           // Reserved
 | ||||
|     std::array<FirmwareSectionHeader, 4> section_headers; // 1st ARM11?, 3rd ARM9
 | ||||
|     std::array<u8, 0x100> signature; // RSA-2048 signature of the FIRM header's hash
 | ||||
| }; | ||||
| 
 | ||||
| struct ARM9_HEADER { | ||||
|     AESKey enc_key_x; | ||||
|     AESKey key_y; | ||||
|     AESKey CTR; | ||||
|     std::array<u8, 8> size;  // in ASCII
 | ||||
|     INSERT_PADDING_BYTES(8); // Unknown
 | ||||
|     std::array<u8, 16> control_block; | ||||
|     std::array<u8, 16> hardware_debug_info; | ||||
|     std::array<u8, 16> enc_key_x_slot_16; | ||||
| }; | ||||
| 
 | ||||
| std::string KeyToString(AESKey& key) { | ||||
|     std::string s; | ||||
|  | @ -170,8 +206,11 @@ void LoadBootromKeys() { | |||
| void LoadNativeFirmKeysOld3DS() { | ||||
|     // Use the save mode native firm instead of the normal mode since there are only 2 version of it
 | ||||
|     // and thus we can use fixed offsets
 | ||||
| 
 | ||||
|     constexpr u64_le save_mode_native_firm_id_low = 0x0004013800000003; | ||||
| 
 | ||||
|     // TODO(B3N30): Add the 0x25 KeyX that gets initalized by native_firm
 | ||||
| 
 | ||||
|     FileSys::NCCHArchive archive(save_mode_native_firm_id_low, Service::FS::MediaType::NAND); | ||||
|     std::array<char, 8> exefs_filepath = {'.', 'f', 'i', 'r', 'm', 0, 0, 0}; | ||||
|     FileSys::Path file_path = FileSys::MakeNCCHFilePath( | ||||
|  | @ -213,6 +252,125 @@ void LoadNativeFirmKeysOld3DS() { | |||
|     } | ||||
| } | ||||
| 
 | ||||
| void LoadNativeFirmKeysNew3DS() { | ||||
|     // The first 0x10 bytes of the secret_sector are used as a key to decrypt a KeyX from the
 | ||||
|     // native_firm
 | ||||
|     const std::string filepath = | ||||
|         FileUtil::GetUserPath(FileUtil::UserPath::SysDataDir) + SECRET_SECTOR; | ||||
|     auto secret = FileUtil::IOFile(filepath, "rb"); | ||||
|     if (!secret) { | ||||
|         return; | ||||
|     } | ||||
|     ASSERT(secret.GetSize() > 0x10); | ||||
| 
 | ||||
|     AESKey secret_key; | ||||
|     secret.ReadArray(secret_key.data(), secret_key.size()); | ||||
| 
 | ||||
|     // Use the save mode native firm instead of the normal mode since there are only 1 version of it
 | ||||
|     // and thus we can use fixed offsets
 | ||||
|     constexpr u64_le save_mode_native_firm_id_low = 0x0004013820000003; | ||||
| 
 | ||||
|     // TODO(B3N30): Add the 0x25 KeyX that gets initalized by native_firm
 | ||||
| 
 | ||||
|     // TODO(B3N30): Add the 0x18 - 0x1F KeyX that gets initalized by native_firm. This probably
 | ||||
|     // requires the normal native firm with version > 9.6.0-X
 | ||||
| 
 | ||||
|     FileSys::NCCHArchive archive(save_mode_native_firm_id_low, Service::FS::MediaType::NAND); | ||||
|     std::array<char, 8> exefs_filepath = {'.', 'f', 'i', 'r', 'm', 0, 0, 0}; | ||||
|     FileSys::Path file_path = FileSys::MakeNCCHFilePath( | ||||
|         FileSys::NCCHFileOpenType::NCCHData, 0, FileSys::NCCHFilePathType::ExeFS, exefs_filepath); | ||||
|     FileSys::Mode open_mode = {}; | ||||
|     open_mode.read_flag.Assign(1); | ||||
|     auto file_result = archive.OpenFile(file_path, open_mode); | ||||
|     if (file_result.Failed()) | ||||
|         return; | ||||
| 
 | ||||
|     auto firm = std::move(file_result).Unwrap(); | ||||
|     std::vector<u8> firm_buffer(firm->GetSize()); | ||||
|     firm->Read(0, firm_buffer.size(), firm_buffer.data()); | ||||
|     firm->Close(); | ||||
| 
 | ||||
|     FIRM_Header header; | ||||
|     std::memcpy(&header, firm_buffer.data(), sizeof(header)); | ||||
| 
 | ||||
|     auto MakeMagic = [](char a, char b, char c, char d) -> u32 { | ||||
|         return a | b << 8 | c << 16 | d << 24; | ||||
|     }; | ||||
|     if (MakeMagic('F', 'I', 'R', 'M') != header.magic) { | ||||
|         LOG_ERROR(HW_AES, "N3DS SAVE MODE Native Firm has wrong header {}", header.magic); | ||||
|         return; | ||||
|     } | ||||
| 
 | ||||
|     u32 arm9_offset(0); | ||||
|     u32 arm9_size(0); | ||||
|     for (auto section_header : header.section_headers) { | ||||
|         if (section_header.firmware_type == FirmwareType::ARM9) { | ||||
|             arm9_offset = section_header.offset; | ||||
|             arm9_size = section_header.size; | ||||
|             break; | ||||
|         } | ||||
|     } | ||||
| 
 | ||||
|     if (arm9_offset != 0x66800) { | ||||
|         LOG_ERROR(HW_AES, "ARM9 binary at wrong offset: {}", arm9_offset); | ||||
|         return; | ||||
|     } | ||||
|     if (arm9_size != 0x8BA00) { | ||||
|         LOG_ERROR(HW_AES, "ARM9 binary has wrong size: {}", arm9_size); | ||||
|         return; | ||||
|     } | ||||
| 
 | ||||
|     ARM9_HEADER arm9_header; | ||||
|     std::memcpy(&arm9_header, firm_buffer.data() + arm9_offset, sizeof(arm9_header)); | ||||
| 
 | ||||
|     AESKey keyX_slot0x15; | ||||
|     CryptoPP::ECB_Mode<CryptoPP::AES>::Decryption d; | ||||
|     d.SetKey(secret_key.data(), secret_key.size()); | ||||
|     d.ProcessData(keyX_slot0x15.data(), arm9_header.enc_key_x.data(), arm9_header.enc_key_x.size()); | ||||
| 
 | ||||
|     key_slots.at(0x15).SetKeyX(keyX_slot0x15); | ||||
|     key_slots.at(0x15).SetKeyY(arm9_header.key_y); | ||||
|     auto normal_key_slot0x15 = key_slots.at(0x15).normal; | ||||
|     if (!normal_key_slot0x15) { | ||||
|         LOG_ERROR(HW_AES, "Failed to get normal key for slot id 0x15"); | ||||
|         return; | ||||
|     } | ||||
| 
 | ||||
|     constexpr u32 ARM9_BINARY_OFFSET = 0x800; // From the beginning of the ARM9 section
 | ||||
|     std::vector<u8> enc_arm9_binary; | ||||
|     enc_arm9_binary.resize(arm9_size - ARM9_BINARY_OFFSET); | ||||
|     ASSERT(enc_arm9_binary.size() + arm9_offset + ARM9_BINARY_OFFSET < firm_buffer.size()); | ||||
|     std::memcpy(enc_arm9_binary.data(), firm_buffer.data() + arm9_offset + ARM9_BINARY_OFFSET, | ||||
|                 enc_arm9_binary.size()); | ||||
| 
 | ||||
|     std::vector<u8> arm9_binary; | ||||
|     arm9_binary.resize(enc_arm9_binary.size()); | ||||
|     CryptoPP::CTR_Mode<CryptoPP::AES>::Decryption d2; | ||||
|     d2.SetKeyWithIV(normal_key_slot0x15->data(), normal_key_slot0x15->size(), | ||||
|                     arm9_header.CTR.data(), arm9_header.CTR.size()); | ||||
|     d2.ProcessData(arm9_binary.data(), enc_arm9_binary.data(), enc_arm9_binary.size()); | ||||
| 
 | ||||
|     AESKey key; | ||||
|     constexpr std::size_t SLOT_0x31_KEY_Y_OFFSET = 517368; | ||||
|     std::memcpy(key.data(), arm9_binary.data() + SLOT_0x31_KEY_Y_OFFSET, sizeof(key)); | ||||
|     key_slots.at(0x31).SetKeyY(key); | ||||
|     LOG_DEBUG(HW_AES, "Loaded Slot0x31 KeyY: {}", KeyToString(key)); | ||||
| 
 | ||||
|     auto LoadCommonKey = [&arm9_binary](std::size_t key_slot) -> AESKey { | ||||
|         constexpr std::size_t START_OFFSET = 541065; | ||||
|         constexpr std::size_t OFFSET = 0x14; // 0x10 bytes for key + 4 bytes between keys
 | ||||
|         AESKey key; | ||||
|         std::memcpy(key.data(), arm9_binary.data() + START_OFFSET + OFFSET * key_slot, sizeof(key)); | ||||
|         return key; | ||||
|     }; | ||||
| 
 | ||||
|     for (std::size_t key_slot{0}; key_slot < 6; ++key_slot) { | ||||
|         AESKey key = LoadCommonKey(key_slot); | ||||
|         common_key_y_slots[key_slot] = key; | ||||
|         LOG_DEBUG(HW_AES, "Loaded common key{}: {}", key_slot, KeyToString(key)); | ||||
|     } | ||||
| } | ||||
| 
 | ||||
| void LoadPresetKeys() { | ||||
|     const std::string filepath = FileUtil::GetUserPath(FileUtil::UserPath::SysDataDir) + AES_KEYS; | ||||
|     FileUtil::CreateFullPath(filepath); // Create path if not already created
 | ||||
|  | @ -288,7 +446,7 @@ void InitKeys() { | |||
|         return; | ||||
|     LoadBootromKeys(); | ||||
|     LoadNativeFirmKeysOld3DS(); | ||||
|     // TODO(B3N30): Load new_3ds save_native_firm
 | ||||
|     LoadNativeFirmKeysNew3DS(); | ||||
|     LoadPresetKeys(); | ||||
|     initialized = true; | ||||
| } | ||||
|  |  | |||
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