1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
|
// Copyright 2018 yuzu emulator team
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <algorithm>
#include <array>
#include <cstring>
#include <regex>
#include <string>
#include <mbedtls/md.h>
#include <mbedtls/sha256.h>
#include "common/assert.h"
#include "common/file_util.h"
#include "common/hex_util.h"
#include "common/logging/log.h"
#include "core/crypto/aes_util.h"
#include "core/crypto/xts_encryption_layer.h"
#include "core/file_sys/partition_filesystem.h"
#include "core/file_sys/vfs_offset.h"
#include "core/file_sys/xts_archive.h"
#include "core/loader/loader.h"
namespace FileSys {
constexpr u64 NAX_HEADER_PADDING_SIZE = 0x4000;
template <typename SourceData, typename SourceKey, typename Destination>
static bool CalculateHMAC256(Destination* out, const SourceKey* key, std::size_t key_length,
const SourceData* data, std::size_t data_length) {
mbedtls_md_context_t context;
mbedtls_md_init(&context);
const auto key_f = reinterpret_cast<const u8*>(key);
const std::vector<u8> key_v(key_f, key_f + key_length);
if (mbedtls_md_setup(&context, mbedtls_md_info_from_type(MBEDTLS_MD_SHA256), 1) ||
mbedtls_md_hmac_starts(&context, reinterpret_cast<const u8*>(key), key_length) ||
mbedtls_md_hmac_update(&context, reinterpret_cast<const u8*>(data), data_length) ||
mbedtls_md_hmac_finish(&context, reinterpret_cast<u8*>(out))) {
mbedtls_md_free(&context);
return false;
}
mbedtls_md_free(&context);
return true;
}
NAX::NAX(VirtualFile file_) : file(std::move(file_)), header(std::make_unique<NAXHeader>()) {
std::string path = FileUtil::SanitizePath(file->GetFullPath());
static const std::regex nax_path_regex("/registered/(000000[0-9A-F]{2})/([0-9A-F]{32})\\.nca",
std::regex_constants::ECMAScript |
std::regex_constants::icase);
std::smatch match;
if (!std::regex_search(path, match, nax_path_regex)) {
status = Loader::ResultStatus::ErrorBadNAXFilePath;
return;
}
std::string two_dir = match[1];
std::string nca_id = match[2];
std::transform(two_dir.begin(), two_dir.end(), two_dir.begin(), ::toupper);
std::transform(nca_id.begin(), nca_id.end(), nca_id.begin(), ::tolower);
status = Parse(fmt::format("/registered/{}/{}.nca", two_dir, nca_id));
}
NAX::NAX(VirtualFile file_, std::array<u8, 0x10> nca_id)
: file(std::move(file_)), header(std::make_unique<NAXHeader>()) {
Core::Crypto::SHA256Hash hash{};
mbedtls_sha256(nca_id.data(), nca_id.size(), hash.data(), 0);
status = Parse(fmt::format("/registered/000000{:02X}/{}.nca", hash[0],
Common::HexArrayToString(nca_id, false)));
}
NAX::~NAX() = default;
Loader::ResultStatus NAX::Parse(std::string_view path) {
if (file->ReadObject(header.get()) != sizeof(NAXHeader))
return Loader::ResultStatus::ErrorBadNAXHeader;
if (header->magic != Common::MakeMagic('N', 'A', 'X', '0'))
return Loader::ResultStatus::ErrorBadNAXHeader;
if (file->GetSize() < NAX_HEADER_PADDING_SIZE + header->file_size)
return Loader::ResultStatus::ErrorIncorrectNAXFileSize;
keys.DeriveSDSeedLazy();
std::array<Core::Crypto::Key256, 2> sd_keys{};
const auto sd_keys_res = Core::Crypto::DeriveSDKeys(sd_keys, keys);
if (sd_keys_res != Loader::ResultStatus::Success) {
return sd_keys_res;
}
const auto enc_keys = header->key_area;
std::size_t i = 0;
for (; i < sd_keys.size(); ++i) {
std::array<Core::Crypto::Key128, 2> nax_keys{};
if (!CalculateHMAC256(nax_keys.data(), sd_keys[i].data(), 0x10, std::string(path).c_str(),
path.size())) {
return Loader::ResultStatus::ErrorNAXKeyHMACFailed;
}
for (std::size_t j = 0; j < nax_keys.size(); ++j) {
Core::Crypto::AESCipher<Core::Crypto::Key128> cipher(nax_keys[j],
Core::Crypto::Mode::ECB);
cipher.Transcode(enc_keys[j].data(), 0x10, header->key_area[j].data(),
Core::Crypto::Op::Decrypt);
}
Core::Crypto::SHA256Hash validation{};
if (!CalculateHMAC256(validation.data(), &header->magic, 0x60, sd_keys[i].data() + 0x10,
0x10)) {
return Loader::ResultStatus::ErrorNAXValidationHMACFailed;
}
if (header->hmac == validation)
break;
}
if (i == 2) {
return Loader::ResultStatus::ErrorNAXKeyDerivationFailed;
}
type = static_cast<NAXContentType>(i);
Core::Crypto::Key256 final_key{};
std::memcpy(final_key.data(), &header->key_area, final_key.size());
const auto enc_file =
std::make_shared<OffsetVfsFile>(file, header->file_size, NAX_HEADER_PADDING_SIZE);
dec_file = std::make_shared<Core::Crypto::XTSEncryptionLayer>(enc_file, final_key);
return Loader::ResultStatus::Success;
}
Loader::ResultStatus NAX::GetStatus() const {
return status;
}
VirtualFile NAX::GetDecrypted() const {
return dec_file;
}
std::shared_ptr<NCA> NAX::AsNCA() const {
if (type == NAXContentType::NCA)
return std::make_shared<NCA>(GetDecrypted());
return nullptr;
}
NAXContentType NAX::GetContentType() const {
return type;
}
std::vector<std::shared_ptr<VfsFile>> NAX::GetFiles() const {
return {dec_file};
}
std::vector<std::shared_ptr<VfsDirectory>> NAX::GetSubdirectories() const {
return {};
}
std::string NAX::GetName() const {
return file->GetName();
}
std::shared_ptr<VfsDirectory> NAX::GetParentDirectory() const {
return file->GetContainingDirectory();
}
bool NAX::ReplaceFileWithSubdirectory(VirtualFile file, VirtualDir dir) {
return false;
}
} // namespace FileSys
|
