diff options
Diffstat (limited to 'src/core/hle/service/nwm/uds_data.cpp')
-rw-r--r-- | src/core/hle/service/nwm/uds_data.cpp | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/src/core/hle/service/nwm/uds_data.cpp b/src/core/hle/service/nwm/uds_data.cpp new file mode 100644 index 000000000..7e4aec624 --- /dev/null +++ b/src/core/hle/service/nwm/uds_data.cpp @@ -0,0 +1,112 @@ +// Copyright 2017 Citra Emulator Project +// Licensed under GPLv2 or any later version +// Refer to the license.txt file included. + +#include <cstring> + +#include "core/hle/service/nwm/nwm_uds.h" +#include "core/hle/service/nwm/uds_data.h" +#include "core/hw/aes/key.h" + +#include <cryptopp/aes.h> +#include <cryptopp/md5.h> +#include <cryptopp/modes.h> + +namespace Service { +namespace NWM { + +// AES Keyslot used to generate the UDS data frame CCMP key. +constexpr size_t UDSDataCryptoAESKeySlot = 0x2D; + +/* + * Generates a SNAP-enabled 802.2 LLC header for the specified protocol. + * @returns a buffer with the bytes of the generated header. + */ +static std::vector<u8> GenerateLLCHeader(EtherType protocol) { + LLCHeader header{}; + header.protocol = static_cast<u16>(protocol); + + std::vector<u8> buffer(sizeof(header)); + memcpy(buffer.data(), &header, sizeof(header)); + + return buffer; +} + +/* + * Generates a Nintendo UDS SecureData header with the specified parameters. + * @returns a buffer with the bytes of the generated header. + */ +static std::vector<u8> GenerateSecureDataHeader(u16 data_size, u8 channel, u16 dest_node_id, + u16 src_node_id, u16 sequence_number) { + SecureDataHeader header{}; + header.protocol_size = data_size + sizeof(SecureDataHeader); + // TODO(Subv): It is likely that the first 4 bytes of this header are actually a decorator for another protocol. + header.securedata_size = data_size + sizeof(SecureDataHeader) - 4; + header.is_management = 0; // Frames sent by the emulated application are never UDS management frames + header.data_channel = channel; + header.sequence_number = sequence_number; + header.dest_node_id = dest_node_id; + header.src_node_id = src_node_id; + + std::vector<u8> buffer(sizeof(header)); + memcpy(buffer.data(), &header, sizeof(header)); + + return buffer; +} + +/* + * Calculates the CTR used for the AES-CTR process that calculates + * the CCMP crypto key for data frames. + * @returns The CTR used for data frames crypto key generation. + */ +static std::array<u8, CryptoPP::MD5::DIGESTSIZE> GetDataCryptoCTR(const NetworkInfo& network_info) { + DataFrameCryptoCTR data{}; + + data.host_mac = network_info.host_mac_address; + data.wlan_comm_id = network_info.wlan_comm_id; + data.id = network_info.id; + data.network_id = network_info.network_id; + + std::array<u8, CryptoPP::MD5::DIGESTSIZE> hash; + CryptoPP::MD5().CalculateDigest(hash.data(), reinterpret_cast<u8*>(&data), sizeof(data)); + + return hash; +} + +/* + * Generates the key used for encrypting the 802.11 data frames generated by UDS. + * @returns The key used for data frames crypto. + */ +static std::array<u8, CryptoPP::AES::BLOCKSIZE> GenerateDataCCMPKey(const std::vector<u8>& passphrase, + const NetworkInfo& network_info) { + // Calculate the MD5 hash of the input passphrase. + std::array<u8, CryptoPP::MD5::DIGESTSIZE> passphrase_hash; + CryptoPP::MD5().CalculateDigest(passphrase_hash.data(), passphrase.data(), passphrase.size()); + + std::array<u8, CryptoPP::AES::BLOCKSIZE> ccmp_key; + + // The CCMP key is the result of encrypting the MD5 hash of the passphrase with AES-CTR using keyslot 0x2D. + using CryptoPP::AES; + std::array<u8, CryptoPP::MD5::DIGESTSIZE> counter = GetDataCryptoCTR(network_info); + std::array<u8, AES::BLOCKSIZE> key = HW::AES::GetNormalKey(UDSDataCryptoAESKeySlot); + CryptoPP::CTR_Mode<AES>::Encryption aes; + aes.SetKeyWithIV(key.data(), AES::BLOCKSIZE, counter.data()); + aes.ProcessData(ccmp_key.data(), passphrase_hash.data(), passphrase_hash.size()); + + return ccmp_key; +} + +std::vector<u8> GenerateDataFrame(const std::vector<u8>& data, u8 channel, u16 dest_node, u16 src_node, u16 sequence_number) { + std::vector<u8> buffer = GenerateLLCHeader(EtherType::SecureData); + std::vector<u8> securedata_header = GenerateSecureDataHeader(data.size(), channel, dest_node, src_node, sequence_number); + + buffer.insert(buffer.end(), securedata_header.begin(), securedata_header.end()); + buffer.insert(buffer.end(), data.begin(), data.end()); + // TODO(Subv): Encrypt the frame. + // TODO(Subv): Prepend CCMP initialization vector (sequence_number). + // TODO(Subv): Encapsulate the frame in an 802.11 data frame. + return buffer; +} + +} // namespace NWM +} // namespace Service |