Merge pull request #1094 from DarkLordZach/nax0

file_sys: Add support for NAX archives

1 files changed, 165 insertions, 7 deletions

diff --git a/src/core/crypto/key_manager.cpp b/src/core/crypto/key_manager.cpp
index db8b22c85..0b6c07de8 100644
--- a/src/core/crypto/key_manager.cpp
+++ b/src/core/crypto/key_manager.cpp
@@ -12,11 +12,112 @@
 #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)),
+    };
+
+    // Combine sources and seed
+    for (auto& source : sd_key_sources) {
+        for (size_t i = 0; i < source.size(); ++i)
+            source[i] ^= sd_seed[i & 0xF];
+    }
+
+    AESCipher<Key128> cipher(sd_kek, Mode::ECB);
+    // The transform manipulates sd_keys as part of the Transcode, so the return/output is
+    // unnecessary. This does not alter sd_keys_sources.
+    std::transform(sd_key_sources.begin(), sd_key_sources.end(), sd_keys.begin(),
+                   sd_key_sources.begin(), [&cipher](const Key256& source, Key256& out) {
+                       cipher.Transcode(source.data(), source.size(), out.data(), Op::Decrypt);
+                       return source; ///< Return unaltered source to satisfy output requirement.
+                   });
+
+    return Loader::ResultStatus::Success;
+}
+
 KeyManager::KeyManager() {
     // Initialize keys
     const std::string hactool_keys_dir = FileUtil::GetHactoolConfigurationPath();
@@ -24,12 +125,15 @@ 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", true);
 }
 
 void KeyManager::LoadFromFile(const std::string& filename, bool is_title_keys) {
@@ -56,17 +160,17 @@ void KeyManager::LoadFromFile(const std::string& filename, bool is_title_keys) {
             u128 rights_id{};
             std::memcpy(rights_id.data(), rights_id_raw.data(), rights_id_raw.size());
             Key128 key = Common::HexStringToArray<16>(out[1]);
-            SetKey(S128KeyType::Titlekey, key, rights_id[1], rights_id[0]);
+            s128_keys[{S128KeyType::Titlekey, rights_id[1], rights_id[0]}] = key;
         } else {
             std::transform(out[0].begin(), out[0].end(), out[0].begin(), ::tolower);
             if (s128_file_id.find(out[0]) != s128_file_id.end()) {
                 const auto index = s128_file_id.at(out[0]);
                 Key128 key = Common::HexStringToArray<16>(out[1]);
-                SetKey(index.type, key, index.field1, index.field2);
+                s128_keys[{index.type, index.field1, index.field2}] = key;
             } else if (s256_file_id.find(out[0]) != s256_file_id.end()) {
                 const auto index = s256_file_id.at(out[0]);
                 Key256 key = Common::HexStringToArray<32>(out[1]);
-                SetKey(index.type, key, index.field1, index.field2);
+                s256_keys[{index.type, index.field1, index.field2}] = key;
             }
         }
     }
@@ -100,11 +204,50 @@ Key256 KeyManager::GetKey(S256KeyType id, u64 field1, u64 field2) const {
     return s256_keys.at({id, field1, field2});
 }
 
+template <size_t Size>
+void KeyManager::WriteKeyToFile(bool title_key, std::string_view keyname,
+                                const std::array<u8, Size>& key) {
+    const std::string yuzu_keys_dir = FileUtil::GetUserPath(FileUtil::UserPath::KeysDir);
+    std::string filename = "title.keys_autogenerated";
+    if (!title_key)
+        filename = dev_mode ? "dev.keys_autogenerated" : "prod.keys_autogenerated";
+    const auto add_info_text = !FileUtil::Exists(yuzu_keys_dir + DIR_SEP + filename);
+    FileUtil::CreateFullPath(yuzu_keys_dir + DIR_SEP + filename);
+    std::ofstream file(yuzu_keys_dir + DIR_SEP + filename, std::ios::app);
+    if (!file.is_open())
+        return;
+    if (add_info_text) {
+        file
+            << "# This file is autogenerated by Yuzu\n"
+            << "# It serves to store keys that were automatically generated from the normal keys\n"
+            << "# If you are experiencing issues involving keys, it may help to delete this file\n";
+    }
+
+    file << fmt::format("\n{} = {}", keyname, Common::HexArrayToString(key));
+    AttemptLoadKeyFile(yuzu_keys_dir, yuzu_keys_dir, filename, title_key);
+}
+
 void KeyManager::SetKey(S128KeyType id, Key128 key, u64 field1, u64 field2) {
+    const auto iter = std::find_if(
+        s128_file_id.begin(), s128_file_id.end(),
+        [&id, &field1, &field2](const std::pair<std::string, KeyIndex<S128KeyType>> elem) {
+            return std::tie(elem.second.type, elem.second.field1, elem.second.field2) ==
+                   std::tie(id, field1, field2);
+        });
+    if (iter != s128_file_id.end())
+        WriteKeyToFile(id == S128KeyType::Titlekey, iter->first, key);
     s128_keys[{id, field1, field2}] = key;
 }
 
 void KeyManager::SetKey(S256KeyType id, Key256 key, u64 field1, u64 field2) {
+    const auto iter = std::find_if(
+        s256_file_id.begin(), s256_file_id.end(),
+        [&id, &field1, &field2](const std::pair<std::string, KeyIndex<S256KeyType>> elem) {
+            return std::tie(elem.second.type, elem.second.field1, elem.second.field2) ==
+                   std::tie(id, field1, field2);
+        });
+    if (iter != s256_file_id.end())
+        WriteKeyToFile(false, iter->first, key);
     s256_keys[{id, field1, field2}] = key;
 }
 
@@ -125,7 +268,16 @@ bool KeyManager::KeyFileExists(bool title) {
            FileUtil::Exists(yuzu_keys_dir + DIR_SEP + "prod.keys");
 }
 
-const std::unordered_map<std::string, KeyIndex<S128KeyType>> KeyManager::s128_file_id = {
+void KeyManager::DeriveSDSeedLazy() {
+    if (HasKey(S128KeyType::SDSeed))
+        return;
+
+    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}},
     {"master_key_02", {S128KeyType::Master, 2, 0}},
@@ -167,11 +319,17 @@ const std::unordered_map<std::string, KeyIndex<S128KeyType>> KeyManager::s128_fi
     {"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 std::unordered_map<std::string, KeyIndex<S256KeyType>> KeyManager::s256_file_id = {
+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