dolphin/Source/Core/Core/HW/WiiSaveCrypted.cpp

// Copyright 2010 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

// Based off of tachtig/twintig http://git.infradead.org/?p=users/segher/wii.git
// Copyright 2007,2008  Segher Boessenkool  <segher@kernel.crashing.org>
// Licensed under the terms of the GNU GPL, version 2
// http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt

#include <cinttypes>
#include <cstddef>
#include <cstdio>
#include <cstring>
#include <memory>
#include <string>
#include <vector>
#include <mbedtls/aes.h>
#include <mbedtls/md5.h>
#include <mbedtls/sha1.h>

#include "Common/CommonFuncs.h"
#include "Common/CommonTypes.h"
#include "Common/FileUtil.h"
#include "Common/MathUtil.h"
#include "Common/MsgHandler.h"
#include "Common/NandPaths.h"
#include "Common/StringUtil.h"
#include "Common/Crypto/ec.h"
#include "Common/Logging/Log.h"

#include "Core/HW/WiiSaveCrypted.h"

static Common::replace_v replacements;

const u8 CWiiSaveCrypted::s_sd_key[16] = {
	0xAB, 0x01, 0xB9, 0xD8, 0xE1, 0x62, 0x2B, 0x08,
	0xAF, 0xBA, 0xD8, 0x4D, 0xBF, 0xC2, 0xA5, 0x5D
};
const u8 CWiiSaveCrypted::s_md5_blanker[16] = {
	0x0E, 0x65, 0x37, 0x81, 0x99, 0xBE, 0x45, 0x17,
	0xAB, 0x06, 0xEC, 0x22, 0x45, 0x1A, 0x57, 0x93
};
const u32 CWiiSaveCrypted::s_ng_id = 0x0403AC68;

bool CWiiSaveCrypted::ImportWiiSave(const std::string& filename)
{
	CWiiSaveCrypted save_file(filename);
	return save_file.m_valid;
}

bool CWiiSaveCrypted::ExportWiiSave(u64 title_id)
{
	CWiiSaveCrypted export_save("", title_id);
	if (export_save.m_valid)
	{
		SuccessAlertT("Successfully exported file to %s",
			export_save.m_encrypted_save_path.c_str());
	}
	else
	{
		PanicAlertT("Export failed");
	}
	return export_save.m_valid;
}

void CWiiSaveCrypted::ExportAllSaves()
{
	std::string title_folder = File::GetUserPath(D_WIIROOT_IDX) + "/title";
	std::vector<u64> titles;
	const u32 path_mask = 0x00010000;
	for (int i = 0; i < 8; ++i)
	{
		std::string folder = StringFromFormat("%s/%08x/", title_folder.c_str(), path_mask | i);
		File::FSTEntry fst_tmp = File::ScanDirectoryTree(folder, false);

		for (const File::FSTEntry& entry : fst_tmp.children)
		{
			if (entry.isDirectory)
			{
				u32 game_id;
				if (AsciiToHex(entry.virtualName, game_id))
				{
					std::string banner_path =
						StringFromFormat("%s%08x/data/banner.bin", folder.c_str(), game_id);
					if (File::Exists(banner_path))
					{
						u64 title_id = (((u64)path_mask | i) << 32) | game_id;
						titles.push_back(title_id);
					}
				}
			}
		}
	}
	SuccessAlertT("Found %zu save files", titles.size());
	u32 success = 0;
	for (const u64& title : titles)
	{
		CWiiSaveCrypted* export_save = new CWiiSaveCrypted("", title);
		if (export_save->m_valid)
			success++;
		delete export_save;
	}
	SuccessAlertT("Successfully exported %u saves to %s", success,
		(File::GetUserPath(D_USER_IDX) + "private/wii/title/").c_str());
}

CWiiSaveCrypted::CWiiSaveCrypted(const std::string& filename, u64 title_id)
	: m_encrypted_save_path(filename), m_title_id(title_id)
{
	Common::ReadReplacements(replacements);
	memcpy(m_sd_iv, "\x21\x67\x12\xE6\xAA\x1F\x68\x9F\x95\xC5\xA2\x23\x24\xDC\x6A\x98", 0x10);

	if (!title_id) // Import
	{
		mbedtls_aes_setkey_dec(&m_aes_ctx, s_sd_key, 128);
		m_valid = true;
		ReadHDR();
		ReadBKHDR();
		ImportWiiSaveFiles();
		// TODO: check_sig()
		if (m_valid)
		{
			SuccessAlertT("Successfully imported save files");
		}
		else
		{
			PanicAlertT("Import failed");
		}
	}
	else
	{
		mbedtls_aes_setkey_enc(&m_aes_ctx, s_sd_key, 128);

		if (getPaths(true))
		{
			m_valid = true;
			WriteHDR();
			WriteBKHDR();
			ExportWiiSaveFiles();
			do_sig();
		}
	}
}

void CWiiSaveCrypted::ReadHDR()
{
	File::IOFile data_file(m_encrypted_save_path, "rb");
	if (!data_file)
	{
		ERROR_LOG(CONSOLE, "Cannot open %s", m_encrypted_save_path.c_str());
		m_valid = false;
		return;
	}
	if (!data_file.ReadBytes(&m_encrypted_header, HEADER_SZ))
	{
		ERROR_LOG(CONSOLE, "Failed to read header");
		m_valid = false;
		return;
	}
	data_file.Close();

	mbedtls_aes_crypt_cbc(&m_aes_ctx, MBEDTLS_AES_DECRYPT, HEADER_SZ, m_sd_iv, (const u8*)&m_encrypted_header,
		(u8*)&m_header);
	u32 banner_size = Common::swap32(m_header.hdr.BannerSize);
	if ((banner_size < FULL_BNR_MIN) || (banner_size > FULL_BNR_MAX) ||
		(((banner_size - BNR_SZ) % ICON_SZ) != 0))
	{
		ERROR_LOG(CONSOLE, "Not a Wii save or read failure for file header size %x", banner_size);
		m_valid = false;
		return;
	}
	m_title_id = Common::swap64(m_header.hdr.SaveGameTitle);


	u8 md5_file[16];
	u8 md5_calc[16];
	memcpy(md5_file, m_header.hdr.Md5, 0x10);
	memcpy(m_header.hdr.Md5, s_md5_blanker, 0x10);
	mbedtls_md5((u8*)&m_header, HEADER_SZ, md5_calc);
	if (memcmp(md5_file, md5_calc, 0x10))
	{
		ERROR_LOG(CONSOLE, "MD5 mismatch\n %016" PRIx64 "%016" PRIx64 " != %016" PRIx64 "%016" PRIx64,
			Common::swap64(md5_file),Common::swap64(md5_file + 8), Common::swap64(md5_calc),
			Common::swap64(md5_calc + 8));
		m_valid= false;
	}

	if (!getPaths())
	{
		m_valid = false;
		return;
	}
	std::string banner_file_path = m_wii_title_path + "banner.bin";
	if (!File::Exists(banner_file_path) ||
		AskYesNoT("%s already exists, overwrite?", banner_file_path.c_str()))
	{
		INFO_LOG(CONSOLE, "Creating file %s", banner_file_path.c_str());
		File::IOFile banner_file(banner_file_path, "wb");
		banner_file.WriteBytes(m_header.BNR, banner_size);
	}
}

void CWiiSaveCrypted::WriteHDR()
{
	if (!m_valid) return;
	memset(&m_header, 0, HEADER_SZ);

	std::string banner_file_path = m_wii_title_path + "banner.bin";
	u32 banner_size = static_cast<u32>(File::GetSize(banner_file_path));
	m_header.hdr.BannerSize = Common::swap32(banner_size);

	m_header.hdr.SaveGameTitle = Common::swap64(m_title_id);
	memcpy(m_header.hdr.Md5, s_md5_blanker, 0x10);
	m_header.hdr.Permissions = 0x3C;

	File::IOFile banner_file(banner_file_path, "rb");
	if (!banner_file.ReadBytes(m_header.BNR, banner_size))
	{
		ERROR_LOG(CONSOLE, "Failed to read banner.bin");
		m_valid = false;
		return;
	}
	// remove nocopy flag
	m_header.BNR[7] &= ~1;

	u8 md5_calc[16];
	mbedtls_md5((u8*)&m_header, HEADER_SZ, md5_calc);
	memcpy(m_header.hdr.Md5, md5_calc, 0x10);

	mbedtls_aes_crypt_cbc(&m_aes_ctx, MBEDTLS_AES_ENCRYPT, HEADER_SZ, m_sd_iv, (const u8*)&m_header,
		(u8*)&m_encrypted_header);

	File::IOFile data_file(m_encrypted_save_path, "wb");
	if (!data_file.WriteBytes(&m_encrypted_header, HEADER_SZ))
	{
		ERROR_LOG(CONSOLE, "Failed to write header for %s", m_encrypted_save_path.c_str());
		m_valid = false;
	}
}



void CWiiSaveCrypted::ReadBKHDR()
{
	if (!m_valid) return;

	File::IOFile fpData_bin(m_encrypted_save_path, "rb");
	if (!fpData_bin)
	{
		ERROR_LOG(CONSOLE, "Cannot open %s", m_encrypted_save_path.c_str());
		m_valid = false;
		return;
	}
	fpData_bin.Seek(HEADER_SZ, SEEK_SET);
	if (!fpData_bin.ReadBytes(&m_bk_hdr, BK_SZ))
	{
		ERROR_LOG(CONSOLE, "Failed to read bk header");
		m_valid = false;
		return;
	}
	fpData_bin.Close();

	if (m_bk_hdr.size  != Common::swap32(BK_LISTED_SZ) ||
		m_bk_hdr.magic != Common::swap32(BK_HDR_MAGIC))
	{
		ERROR_LOG(CONSOLE, "Invalid Size(%x) or Magic word (%x)", m_bk_hdr.size, m_bk_hdr.magic);
		m_valid = false;
		return;
	}

	m_files_list_size = Common::swap32(m_bk_hdr.numberOfFiles);
	m_size_of_files = Common::swap32(m_bk_hdr.sizeOfFiles);
	m_total_size = Common::swap32(m_bk_hdr.totalSize);

	if (m_size_of_files + FULL_CERT_SZ != m_total_size)
	{
		WARN_LOG(CONSOLE, "Size(%x) + cert(%x) does not equal totalsize(%x)", m_size_of_files,
			FULL_CERT_SZ, m_total_size);
	}
	if (m_title_id != Common::swap64(m_bk_hdr.SaveGameTitle))
	{
		WARN_LOG(CONSOLE, "Encrypted title (%" PRIx64 ") does not match unencrypted title (%" PRIx64 ")",
			m_title_id, Common::swap64(m_bk_hdr.SaveGameTitle));
	}
}

void CWiiSaveCrypted::WriteBKHDR()
{
	if (!m_valid) return;
	m_files_list_size = 0;
	m_size_of_files = 0;

	ScanForFiles(m_wii_title_path, m_files_list, &m_files_list_size, &m_size_of_files);
	memset(&m_bk_hdr, 0, BK_SZ);
	m_bk_hdr.size = Common::swap32(BK_LISTED_SZ);
	m_bk_hdr.magic = Common::swap32(BK_HDR_MAGIC);
	m_bk_hdr.NGid = s_ng_id;
	m_bk_hdr.numberOfFiles = Common::swap32(m_files_list_size);
	m_bk_hdr.sizeOfFiles = Common::swap32(m_size_of_files);
	m_bk_hdr.totalSize = Common::swap32(m_size_of_files + FULL_CERT_SZ);
	m_bk_hdr.SaveGameTitle = Common::swap64(m_title_id);

	File::IOFile data_file(m_encrypted_save_path, "ab");
	if (!data_file.WriteBytes(&m_bk_hdr, BK_SZ))
	{
		ERROR_LOG(CONSOLE, "Failed to write bkhdr");
		m_valid = false;
	}
}

void CWiiSaveCrypted::ImportWiiSaveFiles()
{
	if (!m_valid) return;

	File::IOFile data_file(m_encrypted_save_path, "rb");
	if (!data_file)
	{
		ERROR_LOG(CONSOLE, "Cannot open %s", m_encrypted_save_path.c_str());
		m_valid = false;
		return;
	}

	data_file.Seek(HEADER_SZ + BK_SZ, SEEK_SET);

	FileHDR file_hdr_tmp;

	for (u32 i = 0; i < m_files_list_size; ++i)
	{
		memset(&file_hdr_tmp, 0, FILE_HDR_SZ);
		memset(m_iv, 0, 0x10);
		u32 file_size = 0;

		if (!data_file.ReadBytes(&file_hdr_tmp, FILE_HDR_SZ))
		{
			ERROR_LOG(CONSOLE, "Failed to read header for file %d", i);
			m_valid = false;
		}

		if (Common::swap32(file_hdr_tmp.magic) != FILE_HDR_MAGIC)
		{
			ERROR_LOG(CONSOLE, "Bad File Header");
			break;
		}
		else
		{
			std::string filename((char*)file_hdr_tmp.name);
			for (const Common::replace_t& replacement : replacements)
			{
				for (size_t j = 0; (j = filename.find(replacement.first, j)) != filename.npos; ++j)
					filename.replace(j, 1, replacement.second);
			}

			std::string file_path_full = m_wii_title_path + filename;
			File::CreateFullPath(file_path_full);
			if (file_hdr_tmp.type == 1)
			{
				file_size = Common::swap32(file_hdr_tmp.size);
				u32 file_size_rounded = ROUND_UP(file_size, BLOCK_SZ);
				std::vector<u8> file_data(file_size_rounded);
				std::vector<u8> file_data_enc(file_size_rounded);

				if (!data_file.ReadBytes(&file_data_enc[0], file_size_rounded))
				{
					ERROR_LOG(CONSOLE, "Failed to read data from file %d", i);
					m_valid = false;
					break;
				}

				memcpy(m_iv, file_hdr_tmp.IV, 0x10);
				mbedtls_aes_crypt_cbc(&m_aes_ctx, MBEDTLS_AES_DECRYPT, file_size_rounded, m_iv,
					(const u8*)&file_data_enc[0], &file_data[0]);

				if (!File::Exists(file_path_full) ||
					AskYesNoT("%s already exists, overwrite?", file_path_full.c_str()))
				{
					INFO_LOG(CONSOLE, "Creating file %s", file_path_full.c_str());

					File::IOFile raw_save_file(file_path_full, "wb");
					raw_save_file.WriteBytes(&file_data[0], file_size);
				}
			}
		}
	}
}

void CWiiSaveCrypted::ExportWiiSaveFiles()
{
	if (!m_valid) return;

	for (u32 i = 0; i < m_files_list_size; i++)
	{
		FileHDR file_hdr_tmp;
		std::string name;
		memset(&file_hdr_tmp, 0, FILE_HDR_SZ);

		u32 file_size = 0;
		if (File::IsDirectory(m_files_list[i]))
		{
			file_hdr_tmp.type = 2;
		}
		else
		{
			file_size = static_cast<u32>(File::GetSize(m_files_list[i]));
			file_hdr_tmp.type = 1;
		}

		u32 file_size_rounded = ROUND_UP(file_size, BLOCK_SZ);
		file_hdr_tmp.magic = Common::swap32(FILE_HDR_MAGIC);
		file_hdr_tmp.size = Common::swap32(file_size);
		file_hdr_tmp.Permissions = 0x3c;

		name = m_files_list[i].substr(m_wii_title_path.length() + 1);

		for (const Common::replace_t& repl : replacements)
		{
			for (size_t j = 0; (j = name.find(repl.second, j)) != name.npos; ++j)
			{
				name.replace(j, repl.second.length(), 1, repl.first);
			}
		}

		if (name.length() > 0x44)
		{
			ERROR_LOG(CONSOLE, "\"%s\" is too long for the filename, max length is 0x44 + \\0", name.c_str());
			m_valid = false;
			return;
		}
		strncpy((char *)file_hdr_tmp.name, name.c_str(), sizeof(file_hdr_tmp.name));

		{
		File::IOFile fpData_bin(m_encrypted_save_path, "ab");
		fpData_bin.WriteBytes(&file_hdr_tmp, FILE_HDR_SZ);
		}

		if (file_hdr_tmp.type == 1)
		{
			if (file_size == 0)
			{
				ERROR_LOG(CONSOLE, "%s is a 0 byte file", m_files_list[i].c_str());
				m_valid = false;
				return;
			}
			File::IOFile raw_save_file(m_files_list[i], "rb");
			if (!raw_save_file)
			{
				ERROR_LOG(CONSOLE, "%s failed to open", m_files_list[i].c_str());
				m_valid = false;
			}

			std::vector<u8> file_data(file_size_rounded);
			std::vector<u8> file_data_enc(file_size_rounded);

			if (!raw_save_file.ReadBytes(&file_data[0], file_size))
			{
				ERROR_LOG(CONSOLE, "Failed to read data from file: %s",
					m_files_list[i].c_str());
				m_valid = false;
			}

			mbedtls_aes_crypt_cbc(&m_aes_ctx, MBEDTLS_AES_ENCRYPT, file_size_rounded,
				file_hdr_tmp.IV, (const u8*)&file_data[0], &file_data_enc[0]);

			File::IOFile fpData_bin(m_encrypted_save_path, "ab");
			if (!fpData_bin.WriteBytes(&file_data_enc[0], file_size_rounded))
			{
				ERROR_LOG(CONSOLE, "Failed to write data to file: %s",
					m_encrypted_save_path.c_str());
			}
		}
	}
}

void CWiiSaveCrypted::do_sig()
{
	if (!m_valid) return;
	u8 sig[0x40];
	u8 ng_cert[0x180];
	u8 ap_cert[0x180];
	u8 hash[0x14];
	u8 ap_priv[30];
	u8 ap_sig[60];
	char signer[64];
	char name[64];
	u32 data_size;

	const u32 ng_key_id = 0x6AAB8C59;

	const u8 ng_priv[30] = {
		0, 0xAB, 0xEE, 0xC1, 0xDD, 0xB4, 0xA6, 0x16, 0x6B, 0x70, 0xFD, 0x7E, 0x56, 0x67, 0x70,
		0x57, 0x55, 0x27, 0x38, 0xA3, 0x26, 0xC5, 0x46, 0x16, 0xF7, 0x62, 0xC9, 0xED, 0x73, 0xF2
	};

	const u8 ng_sig[0x3C] = {
		0, 0xD8, 0x81, 0x63, 0xB2, 0x00, 0x6B, 0x0B, 0x54, 0x82, 0x88, 0x63, 0x81, 0x1C, 0x00,
		0x71, 0x12, 0xED, 0xB7, 0xFD, 0x21, 0xAB, 0x0E, 0x50, 0x0E, 0x1F, 0xBF, 0x78, 0xAD, 0x37,
		0x00, 0x71, 0x8D, 0x82, 0x41, 0xEE, 0x45, 0x11, 0xC7, 0x3B, 0xAC, 0x08, 0xB6, 0x83, 0xDC,
		0x05, 0xB8, 0xA8, 0x90, 0x1F, 0xA8, 0x2A, 0x0E, 0x4E, 0x76, 0xEF, 0x44, 0x72, 0x99, 0xF8
	};

	sprintf(signer, "Root-CA00000001-MS00000002");
	sprintf(name, "NG%08x", s_ng_id);
	make_ec_cert(ng_cert, ng_sig, signer, name, ng_priv, ng_key_id);


	memset(ap_priv, 0, sizeof ap_priv);
	ap_priv[10] = 1;

	memset(ap_sig, 81, sizeof ap_sig); // temp

	sprintf(signer, "Root-CA00000001-MS00000002-NG%08x", s_ng_id);
	sprintf(name, "AP%08x%08x", 1, 2);
	make_ec_cert(ap_cert, ap_sig, signer, name, ap_priv, 0);

	mbedtls_sha1(ap_cert + 0x80, 0x100, hash);
	generate_ecdsa(ap_sig, ap_sig + 30, ng_priv, hash);
	make_ec_cert(ap_cert, ap_sig, signer, name, ap_priv, 0);

	data_size = Common::swap32(m_bk_hdr.sizeOfFiles) + 0x80;

	File::IOFile data_file(m_encrypted_save_path, "rb");
	if (!data_file)
	{
		m_valid = false;
		return;
	}
	auto data = std::make_unique<u8[]>(data_size);

	data_file.Seek(0xf0c0, SEEK_SET);
	if (!data_file.ReadBytes(data.get(), data_size))
	{
		m_valid = false;
		return;
	}

	mbedtls_sha1(data.get(), data_size, hash);
	mbedtls_sha1(hash, 20, hash);

	data_file.Open(m_encrypted_save_path, "ab");
	if (!data_file)
	{
		m_valid = false;
		return;
	}
	generate_ecdsa(sig, sig + 30, ap_priv, hash);
	*(u32*)(sig + 60) = Common::swap32(0x2f536969);

	data_file.WriteArray(sig, sizeof(sig));
	data_file.WriteArray(ng_cert, sizeof(ng_cert));
	data_file.WriteArray(ap_cert, sizeof(ap_cert));

	m_valid = data_file.IsGood();
}

void CWiiSaveCrypted::make_ec_cert(u8 *cert, const u8 *sig, const char *signer, const char *name,
	const u8 *priv, const u32 key_id)
{
	memset(cert, 0, 0x180);
	*(u32*)cert = Common::swap32(0x10002);

	memcpy(cert + 4, sig, 60);
	strcpy((char*)cert + 0x80, signer);
	*(u32*)(cert + 0xc0) = Common::swap32(2);
	strcpy((char*)cert + 0xc4, name);
	*(u32*)(cert + 0x104) = Common::swap32(key_id);
	ec_priv_to_pub(priv, cert + 0x108);
}

bool CWiiSaveCrypted::getPaths(bool for_export)
{
	if (m_title_id)
	{
		// CONFIGURED because this whole class is only used from the GUI, not directly by games.
		m_wii_title_path = Common::GetTitleDataPath(m_title_id, Common::FROM_CONFIGURED_ROOT);
	}

	if (for_export)
	{
		char game_id[5];
		sprintf(game_id, "%c%c%c%c",
			(u8)(m_title_id >> 24) & 0xFF, (u8)(m_title_id >> 16) & 0xFF,
			(u8)(m_title_id >> 8) & 0xFF, (u8)m_title_id & 0xFF);

		if (!File::IsDirectory(m_wii_title_path))
		{
			m_valid = false;
			ERROR_LOG(CONSOLE, "No save folder found for title %s", game_id);
			return false;
		}

		if (!File::Exists(m_wii_title_path + "banner.bin"))
		{
			m_valid = false;
			ERROR_LOG(CONSOLE, "No banner file found for title  %s", game_id);
			return false;
		}
		if (m_encrypted_save_path.length() == 0)
		{
			// If no path was passed, use User folder
			m_encrypted_save_path = File::GetUserPath(D_USER_IDX);
		}
		m_encrypted_save_path += StringFromFormat("private/wii/title/%s/data.bin", game_id);
		File::CreateFullPath(m_encrypted_save_path);
	}
	else
	{
		File::CreateFullPath(m_wii_title_path);
		if (!AskYesNoT(
			"Warning! it is advised to backup all files in the folder:\n%s\nDo you wish to continue?",
			m_wii_title_path.c_str()))
		{
			return false;
		}
	}
	return true;
}

void CWiiSaveCrypted::ScanForFiles(const std::string& save_directory, std::vector<std::string>& file_list,
	u32 *num_files, u32 *size_files)
{
	std::vector<std::string> directories;
	directories.push_back(save_directory);
	u32 num = 0;
	u32 size = 0;

	for (u32 i = 0; i < directories.size(); ++i)
	{
		if (i != 0)
		{
			// add dir to fst
			file_list.push_back(directories[i]);
		}

		File::FSTEntry fst_tmp = File::ScanDirectoryTree(directories[i], false);
		for (const File::FSTEntry& elem : fst_tmp.children)
		{
			if (elem.virtualName != "banner.bin")
			{
				num++;
				size += FILE_HDR_SZ;
				if (elem.isDirectory)
				{
					if (elem.virtualName == "nocopy" || elem.virtualName == "nomove")
					{
						NOTICE_LOG(CONSOLE,
							"This save will likely require homebrew tools to copy to a real Wii.");
					}

					directories.push_back(elem.physicalName);
				}
				else
				{
					file_list.push_back(elem.physicalName);
					size += ROUND_UP(elem.size, BLOCK_SZ);
				}
			}
		}
	}

	*num_files = num;
	*size_files = size;
}

CWiiSaveCrypted::~CWiiSaveCrypted()
{
}