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key_manager: Add support for KEK and SD seed derivation

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This commit is contained in:
Zach Hilman 2018-08-16 17:12:05 -04:00
parent cde665c565
commit f26fc64cb4
2 changed files with 135 additions and 5 deletions
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114
src/core/crypto/key_manager.cpp
View file

@ -12,11 +12,105 @@
#include "common/file_util.h"
#include "common/hex_util.h"
#include "common/logging/log.h"
#include "core/crypto/aes_util.h"
#include "core/crypto/key_manager.h"
#include "core/settings.h"
namespace Core::Crypto {
Key128 GenerateKeyEncryptionKey(Key128 source, Key128 master, Key128 kek_seed, Key128 key_seed) {
Key128 out{};
AESCipher<Key128> cipher1(master, Mode::ECB);
cipher1.Transcode(kek_seed.data(), kek_seed.size(), out.data(), Op::Decrypt);
AESCipher<Key128> cipher2(out, Mode::ECB);
cipher2.Transcode(source.data(), source.size(), out.data(), Op::Decrypt);
if (key_seed != Key128{}) {
AESCipher<Key128> cipher3(out, Mode::ECB);
cipher3.Transcode(key_seed.data(), key_seed.size(), out.data(), Op::Decrypt);
}
return out;
}
boost::optional<Key128> DeriveSDSeed() {
const FileUtil::IOFile save_43(FileUtil::GetUserPath(FileUtil::UserPath::NANDDir) +
"/system/save/8000000000000043",
"rb+");
if (!save_43.IsOpen())
return boost::none;
const FileUtil::IOFile sd_private(
FileUtil::GetUserPath(FileUtil::UserPath::SDMCDir) + "/Nintendo/Contents/private", "rb+");
if (!sd_private.IsOpen())
return boost::none;
sd_private.Seek(0, SEEK_SET);
std::array<u8, 0x10> private_seed{};
if (sd_private.ReadBytes(private_seed.data(), private_seed.size()) != 0x10)
return boost::none;
std::array<u8, 0x10> buffer{};
size_t offset = 0;
for (; offset + 0x10 < save_43.GetSize(); ++offset) {
save_43.Seek(offset, SEEK_SET);
save_43.ReadBytes(buffer.data(), buffer.size());
if (buffer == private_seed)
break;
}
if (offset + 0x10 >= save_43.GetSize())
return boost::none;
Key128 seed{};
save_43.Seek(offset + 0x10, SEEK_SET);
save_43.ReadBytes(seed.data(), seed.size());
return seed;
}
Loader::ResultStatus DeriveSDKeys(std::array<Key256, 2>& sd_keys, const KeyManager& keys) {
if (!keys.HasKey(S128KeyType::Source, static_cast<u64>(SourceKeyType::SDKEK)))
return Loader::ResultStatus::ErrorMissingSDKEKSource;
if (!keys.HasKey(S128KeyType::Source, static_cast<u64>(SourceKeyType::AESKEKGeneration)))
return Loader::ResultStatus::ErrorMissingAESKEKGenerationSource;
if (!keys.HasKey(S128KeyType::Source, static_cast<u64>(SourceKeyType::AESKeyGeneration)))
return Loader::ResultStatus::ErrorMissingAESKeyGenerationSource;
const auto sd_kek_source =
keys.GetKey(S128KeyType::Source, static_cast<u64>(SourceKeyType::SDKEK));
const auto aes_kek_gen =
keys.GetKey(S128KeyType::Source, static_cast<u64>(SourceKeyType::AESKEKGeneration));
const auto aes_key_gen =
keys.GetKey(S128KeyType::Source, static_cast<u64>(SourceKeyType::AESKeyGeneration));
const auto master_00 = keys.GetKey(S128KeyType::Master);
const auto sd_kek =
GenerateKeyEncryptionKey(sd_kek_source, master_00, aes_kek_gen, aes_key_gen);
if (!keys.HasKey(S128KeyType::SDSeed))
return Loader::ResultStatus::ErrorMissingSDSeed;
const auto sd_seed = keys.GetKey(S128KeyType::SDSeed);
if (!keys.HasKey(S256KeyType::SDKeySource, static_cast<u64>(SDKeyType::Save)))
return Loader::ResultStatus::ErrorMissingSDSaveKeySource;
if (!keys.HasKey(S256KeyType::SDKeySource, static_cast<u64>(SDKeyType::NCA)))
return Loader::ResultStatus::ErrorMissingSDNCAKeySource;
std::array<Key256, 2> sd_key_sources{
keys.GetKey(S256KeyType::SDKeySource, static_cast<u64>(SDKeyType::Save)),
keys.GetKey(S256KeyType::SDKeySource, static_cast<u64>(SDKeyType::NCA)),
};
AESCipher<Key128> cipher(sd_kek, Mode::ECB);
for (size_t i = 0; i < 2; ++i) {
for (size_t j = 0; j < 0x20; ++j)
sd_key_sources[i][j] ^= sd_seed[j & 0xF];
cipher.Transcode(sd_key_sources[i].data(), sd_key_sources[i].size(), sd_keys[i].data(),
Op::Decrypt);
}
return Loader::ResultStatus::Success;
}
KeyManager::KeyManager() {
// Initialize keys
const std::string hactool_keys_dir = FileUtil::GetHactoolConfigurationPath();
@ -24,12 +118,15 @@ KeyManager::KeyManager() {
if (Settings::values.use_dev_keys) {
dev_mode = true;
AttemptLoadKeyFile(yuzu_keys_dir, hactool_keys_dir, "dev.keys", false);
AttemptLoadKeyFile(yuzu_keys_dir, yuzu_keys_dir, "dev.keys_autogenerated", false);
} else {
dev_mode = false;
AttemptLoadKeyFile(yuzu_keys_dir, hactool_keys_dir, "prod.keys", false);
AttemptLoadKeyFile(yuzu_keys_dir, yuzu_keys_dir, "prod.keys_autogenerated", false);
}
AttemptLoadKeyFile(yuzu_keys_dir, hactool_keys_dir, "title.keys", true);
AttemptLoadKeyFile(yuzu_keys_dir, yuzu_keys_dir, "title.keys_autogenerated", false);
}
void KeyManager::LoadFromFile(const std::string& filename, bool is_title_keys) {
@ -126,6 +223,13 @@ bool KeyManager::KeyFileExists(bool title) {
}
void KeyManager::DeriveSDSeedLazy() {
if (!HasKey(S128KeyType::SDSeed)) {
const auto res = DeriveSDSeed();
if (res != boost::none)
SetKey(S128KeyType::SDSeed, res.get());
}
}
const boost::container::flat_map<std::string, KeyIndex<S128KeyType>> KeyManager::s128_file_id = {
{"master_key_00", {S128KeyType::Master, 0, 0}},
{"master_key_01", {S128KeyType::Master, 1, 0}},
@ -168,11 +272,17 @@ const boost::container::flat_map<std::string, KeyIndex<S128KeyType>> KeyManager:
{"key_area_key_system_02", {S128KeyType::KeyArea, 2, static_cast<u64>(KeyAreaKeyType::System)}},
{"key_area_key_system_03", {S128KeyType::KeyArea, 3, static_cast<u64>(KeyAreaKeyType::System)}},
{"key_area_key_system_04", {S128KeyType::KeyArea, 4, static_cast<u64>(KeyAreaKeyType::System)}},
{"sd_card_kek_source", {S128KeyType::Source, static_cast<u64>(SourceKeyType::SDKEK), 0}},
{"aes_kek_generation_source",
{S128KeyType::Source, static_cast<u64>(SourceKeyType::AESKEKGeneration), 0}},
{"aes_key_generation_source",
{S128KeyType::Source, static_cast<u64>(SourceKeyType::AESKeyGeneration), 0}},
{"sd_seed", {S128KeyType::SDSeed, 0, 0}},
};
const boost::container::flat_map<std::string, KeyIndex<S256KeyType>> KeyManager::s256_file_id = {
{"header_key", {S256KeyType::Header, 0, 0}},
{"sd_card_save_key", {S256KeyType::SDSave, 0, 0}},
{"sd_card_nca_key", {S256KeyType::SDNCA, 0, 0}},
{"sd_card_save_key_source", {S256KeyType::SDKeySource, static_cast<u64>(SDKeyType::Save), 0}},
{"sd_card_nca_key_source", {S256KeyType::SDKeySource, static_cast<u64>(SDKeyType::NCA), 0}},
};
} // namespace Core::Crypto

26
src/core/crypto/key_manager.h
View file

@ -23,9 +23,8 @@ static_assert(sizeof(Key128) == 16, "Key128 must be 128 bytes big.");
static_assert(sizeof(Key256) == 32, "Key128 must be 128 bytes big.");
enum class S256KeyType : u64 {
Header, //
SDSave, //
SDNCA, //
Header, //
SDKeySource, // f1=SDKeyType
};
enum class S128KeyType : u64 {
@ -37,6 +36,7 @@ enum class S128KeyType : u64 {
KeyArea, // f1=crypto revision f2=type {app, ocean, system}
SDSeed, //
Titlekey, // f1=rights id LSB f2=rights id MSB
Source, // f1=source type, f2= sub id
};
enum class KeyAreaKeyType : u8 {
@ -45,6 +45,17 @@ enum class KeyAreaKeyType : u8 {
System,
};
enum class SourceKeyType : u8 {
SDKEK,
AESKEKGeneration,
AESKeyGeneration,
};
enum class SDKeyType : u8 {
Save,
NCA,
};
template <typename KeyType>
struct KeyIndex {
KeyType type;
@ -83,6 +94,10 @@ public:
static bool KeyFileExists(bool title);
// Call before using the sd seed to attempt to derive it if it dosen't exist. Needs system save
// 8*43 and the private file to exist.
void DeriveSDSeedLazy();
private:
boost::container::flat_map<KeyIndex<S128KeyType>, Key128> s128_keys;
boost::container::flat_map<KeyIndex<S256KeyType>, Key256> s256_keys;
@ -95,4 +110,9 @@ private:
static const boost::container::flat_map<std::string, KeyIndex<S128KeyType>> s128_file_id;
static const boost::container::flat_map<std::string, KeyIndex<S256KeyType>> s256_file_id;
};
Key128 GenerateKeyEncryptionKey(Key128 source, Key128 master, Key128 kek_seed, Key128 key_seed);
boost::optional<Key128> DeriveSDSeed();
Loader::ResultStatus DeriveSDKeys(std::array<Key256, 2>& sd_keys, const KeyManager& keys);
} // namespace Core::Crypto