NCA decryption (#99)

* NCA decryption
* Remove unnecessary new lines
* Remove loader error dialog
* Always show ROMs
* Address CRs
* Add subtitle padding in grid mode

app/CMakeLists.txt

@@ -12,7 +12,7 @@ set(source_DIR ${CMAKE_SOURCE_DIR}/src/main/cpp)
 set(CMAKE_CXX_FLAGS_RELEASE "-Ofast -flto=full -Wno-unused-command-line-argument")
 if (uppercase_CMAKE_BUILD_TYPE STREQUAL "RELEASE")
     add_compile_definitions(NDEBUG)
-endif()
+endif ()
 
 set(CMAKE_POLICY_DEFAULT_CMP0048 OLD)
 add_subdirectory("libraries/tinyxml2")
@@ -24,6 +24,8 @@ include_directories("libraries/oboe/include")
 include_directories("libraries/vkhpp/include")
 set(CMAKE_POLICY_DEFAULT_CMP0048 NEW)
 
+find_package(mbedtls REQUIRED CONFIG)
+
 include_directories(${source_DIR}/skyline)
 
 add_library(skyline SHARED
@@ -38,6 +40,8 @@ add_library(skyline SHARED
         ${source_DIR}/skyline/audio/track.cpp
         ${source_DIR}/skyline/audio/resampler.cpp
         ${source_DIR}/skyline/audio/adpcm_decoder.cpp
+        ${source_DIR}/skyline/crypto/aes_cipher.cpp
+        ${source_DIR}/skyline/crypto/key_store.cpp
         ${source_DIR}/skyline/gpu.cpp
         ${source_DIR}/skyline/gpu/macro_interpreter.cpp
         ${source_DIR}/skyline/gpu/memory_manager.cpp
@@ -144,12 +148,13 @@ add_library(skyline SHARED
         ${source_DIR}/skyline/services/prepo/IPrepoService.cpp
         ${source_DIR}/skyline/vfs/os_filesystem.cpp
         ${source_DIR}/skyline/vfs/partition_filesystem.cpp
+        ${source_DIR}/skyline/vfs/ctr_encrypted_backing.cpp
         ${source_DIR}/skyline/vfs/rom_filesystem.cpp
         ${source_DIR}/skyline/vfs/os_backing.cpp
         ${source_DIR}/skyline/vfs/nacp.cpp
         ${source_DIR}/skyline/vfs/nca.cpp
         )
 
-target_link_libraries(skyline vulkan android fmt tinyxml2 oboe lz4_static)
+target_link_libraries(skyline vulkan android fmt tinyxml2 oboe lz4_static mbedtls::mbedcrypto)
 set(CMAKE_CXX17_EXTENSION_COMPILE_OPTION "-std=c++2a")
 target_compile_options(skyline PRIVATE -Wno-c++17-extensions -Wall -Wno-reorder -Wno-missing-braces -Wno-unused-variable -Wno-unused-private-field)

app/build.gradle

@@ -40,6 +40,9 @@ android {
             shrinkResources false
         }
     }
+    androidExtensions {
+        experimental = true
+    }
     externalNativeBuild {
         cmake {
             version "3.10.2+"
@@ -63,7 +66,11 @@ dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
     implementation 'androidx.documentfile:documentfile:1.0.1'
     implementation 'info.debatty:java-string-similarity:1.2.1'
+    implementation(name: 'mbedtls', ext: 'aar')
 }
 repositories {
     mavenCentral()
+    flatDir {
+        dirs 'libraries'
+    }
 }

app/proguard-rules.pro

@@ -1,9 +1,3 @@
 # Skyline Proguard Rules
 # For more details, see
 #   http://developer.android.com/guide/developing/tools/proguard.html
-
--keep class emu.skyline.loader.AppEntry {
-    void writeObject(java.io.ObjectOutputStream);
-    void readObject(java.io.ObjectInputStream);
-}
--keep class emu.skyline.GameActivity { *; }

app/src/main/AndroidManifest.xml

@@ -3,7 +3,6 @@
         xmlns:tools="http://schemas.android.com/tools"
         package="emu.skyline">
 
-    <uses-permission android:name="android.permission.READ_INTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.INTERNET" />
 
     <uses-feature
@@ -47,6 +46,11 @@
                     android:name="android.support.PARENT_ACTIVITY"
                     android:value="emu.skyline.SettingsActivity" />
         </activity>
+        <activity android:name="emu.skyline.preference.FileActivity">
+            <meta-data
+                    android:name="android.support.PARENT_ACTIVITY"
+                    android:value="emu.skyline.SettingsActivity" />
+        </activity>
         <activity
                 android:name="emu.skyline.input.ControllerActivity"
                 android:exported="true">

app/src/main/cpp/loader_jni.cpp

@@ -1,6 +1,8 @@
 // SPDX-License-Identifier: MPL-2.0
 // Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)
 
+#include "skyline/crypto/key_store.h"
+#include "skyline/vfs/nca.h"
 #include "skyline/vfs/os_backing.h"
 #include "skyline/loader/nro.h"
 #include "skyline/loader/nso.h"
@@ -8,54 +10,53 @@
 #include "skyline/loader/nsp.h"
 #include "skyline/jvm.h"
 
-extern "C" JNIEXPORT jlong JNICALL Java_emu_skyline_loader_RomFile_initialize(JNIEnv *env, jobject thiz, jint jformat, jint fd) {
+extern "C" JNIEXPORT jint JNICALL Java_emu_skyline_loader_RomFile_populate(JNIEnv *env, jobject thiz, jint jformat, jint fd, jstring appFilesPathJstring) {
-    skyline::loader::RomFormat format = static_cast<skyline::loader::RomFormat>(jformat);
+    skyline::loader::RomFormat format{static_cast<skyline::loader::RomFormat>(jformat)};
 
+    auto appFilesPath{env->GetStringUTFChars(appFilesPathJstring, nullptr)};
+    auto keyStore{std::make_shared<skyline::crypto::KeyStore>(appFilesPath)};
+    env->ReleaseStringUTFChars(appFilesPathJstring, appFilesPath);
+
+    std::unique_ptr<skyline::loader::Loader> loader;
     try {
-        auto backing = std::make_shared<skyline::vfs::OsBacking>(fd);
+        auto backing{std::make_shared<skyline::vfs::OsBacking>(fd)};
 
         switch (format) {
             case skyline::loader::RomFormat::NRO:
-                return reinterpret_cast<jlong>(new skyline::loader::NroLoader(backing));
+                loader = std::make_unique<skyline::loader::NroLoader>(backing);
+                break;
             case skyline::loader::RomFormat::NSO:
-                return reinterpret_cast<jlong>(new skyline::loader::NsoLoader(backing));
+                loader = std::make_unique<skyline::loader::NsoLoader>(backing);
+                break;
             case skyline::loader::RomFormat::NCA:
-                return reinterpret_cast<jlong>(new skyline::loader::NcaLoader(backing));
+                loader = std::make_unique<skyline::loader::NcaLoader>(backing, keyStore);
+                break;
             case skyline::loader::RomFormat::NSP:
-                return reinterpret_cast<jlong>(new skyline::loader::NspLoader(backing));
+                loader = std::make_unique<skyline::loader::NspLoader>(backing, keyStore);
+                break;
             default:
-                return 0;
+                return static_cast<jint>(skyline::loader::LoaderResult::ParsingError);
         }
+    } catch (const skyline::loader::loader_exception &e) {
+        return static_cast<jint>(e.error);
     } catch (const std::exception &e) {
-        return 0;
+        return static_cast<jint>(skyline::loader::LoaderResult::ParsingError);
     }
-}
+
-
+    jclass clazz{env->GetObjectClass(thiz)};
-extern "C" JNIEXPORT jboolean JNICALL Java_emu_skyline_loader_RomFile_hasAssets(JNIEnv *env, jobject thiz, jlong instance) {
+    jfieldID applicationNameField{env->GetFieldID(clazz, "applicationName", "Ljava/lang/String;")};
-    return reinterpret_cast<skyline::loader::Loader *>(instance)->nacp != nullptr;
+    jfieldID applicationAuthorField{env->GetFieldID(clazz, "applicationAuthor", "Ljava/lang/String;")};
-}
+    jfieldID rawIconField{env->GetFieldID(clazz, "rawIcon", "[B")};
-
+
-extern "C" JNIEXPORT jbyteArray JNICALL Java_emu_skyline_loader_RomFile_getIcon(JNIEnv *env, jobject thiz, jlong instance) {
+    if (loader->nacp) {
-    std::vector<skyline::u8> buffer = reinterpret_cast<skyline::loader::Loader *>(instance)->GetIcon();
+        env->SetObjectField(thiz, applicationNameField, env->NewStringUTF(loader->nacp->applicationName.c_str()));
-
+        env->SetObjectField(thiz, applicationAuthorField, env->NewStringUTF(loader->nacp->applicationPublisher.c_str()));
-    jbyteArray result = env->NewByteArray(buffer.size());
+
-    env->SetByteArrayRegion(result, 0, buffer.size(), reinterpret_cast<const jbyte *>(buffer.data()));
+        auto icon{loader->GetIcon()};
-
+        jbyteArray iconByteArray{env->NewByteArray(icon.size())};
-    return result;
+        env->SetByteArrayRegion(iconByteArray, 0, icon.size(), reinterpret_cast<const jbyte *>(icon.data()));
-}
+        env->SetObjectField(thiz, rawIconField, iconByteArray);
-
+    }
-extern "C" JNIEXPORT jstring JNICALL Java_emu_skyline_loader_RomFile_getApplicationName(JNIEnv *env, jobject thiz, jlong instance) {
+
-    std::string applicationName = reinterpret_cast<skyline::loader::Loader *>(instance)->nacp->applicationName;
+    return static_cast<jint>(skyline::loader::LoaderResult::Success);
-
-    return env->NewStringUTF(applicationName.c_str());
-}
-
-extern "C" JNIEXPORT jstring JNICALL Java_emu_skyline_loader_RomFile_getApplicationPublisher(JNIEnv *env, jobject thiz, jlong instance) {
-    std::string applicationPublisher = reinterpret_cast<skyline::loader::Loader *>(instance)->nacp->applicationPublisher;
-
-    return env->NewStringUTF(applicationPublisher.c_str());
-}
-
-extern "C" JNIEXPORT void JNICALL Java_emu_skyline_loader_RomFile_destroy(JNIEnv *env, jobject thiz, jlong instance) {
-    delete reinterpret_cast<skyline::loader::NroLoader *>(instance);
 }

app/src/main/cpp/skyline/common.h

@@ -62,6 +62,19 @@ namespace skyline {
         constexpr u16 DockedResolutionH = 1080; //!< The height component of the docked resolution
         // Time
         constexpr u64 NsInSecond = 1000000000; //!< This is the amount of nanoseconds in a second
+    }
+
+    /**
+     * @brief This is a std::runtime_error with libfmt formatting
+     */
+    class exception : public std::runtime_error {
+      public:
+        /**
+         * @param formatStr The exception string to be written, with libfmt formatting
+         * @param args The arguments based on format_str
+         */
+        template<typename S, typename... Args>
+        inline exception(const S &formatStr, Args &&... args) : runtime_error(fmt::format(formatStr, args...)) {}
     };
 
     namespace util {
@@ -159,6 +172,28 @@ namespace skyline {
 
             return object;
         }
+
+        constexpr u8 HexDigitToByte(char digit) {
+            if (digit >= '0' && digit <= '9')
+                return digit - '0';
+            else if (digit >= 'a' && digit <= 'f')
+                return digit - 'a' + 10;
+            else if (digit >= 'A' && digit <= 'F')
+                return digit - 'A' + 10;
+            throw exception(fmt::format("Invalid hex char {}", digit));
+        }
+
+        template<size_t Size>
+        constexpr std::array<u8, Size> HexStringToArray(const std::string_view &hexString) {
+            if (hexString.size() != Size * 2)
+                throw exception("Invalid size");
+            std::array<u8, Size> result;
+            for (size_t i{}; i < Size; ++i) {
+                size_t hexStrIndex{i * 2};
+                result[i] = (HexDigitToByte(hexString[hexStrIndex]) << 4) | HexDigitToByte(hexString[hexStrIndex + 1]);
+            }
+            return result;
+        }
     }
 
     /**
@@ -350,19 +385,6 @@ namespace skyline {
         void List(const std::shared_ptr<Logger> &logger);
     };
 
-    /**
-     * @brief This is a std::runtime_error with libfmt formatting
-     */
-    class exception : public std::runtime_error {
-      public:
-        /**
-         * @param formatStr The exception string to be written, with libfmt formatting
-         * @param args The arguments based on format_str
-         */
-        template<typename S, typename... Args>
-        inline exception(const S &formatStr, Args &&... args) : runtime_error(fmt::format(formatStr, args...)) {}
-    };
-
     class NCE;
     class JvmManager;
     namespace gpu {

app/src/main/cpp/skyline/crypto/aes_cipher.cpp

@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: MPL-2.0
+// Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)
+
+#include "aes_cipher.h"
+
+namespace skyline::crypto {
+    AesCipher::AesCipher(std::span<u8> key, mbedtls_cipher_type_t type) {
+        mbedtls_cipher_init(&decryptContext);
+        if (mbedtls_cipher_setup(&decryptContext, mbedtls_cipher_info_from_type(type)) != 0)
+            throw exception("Failed to setup decryption context");
+
+        if (mbedtls_cipher_setkey(&decryptContext, key.data(), key.size() * 8, MBEDTLS_DECRYPT) != 0)
+            throw exception("Failed to set key for decryption context");
+    }
+
+    AesCipher::~AesCipher() {
+        mbedtls_cipher_free(&decryptContext);
+    }
+
+    void AesCipher::SetIV(const std::array<u8, 0x10> &iv) {
+        if (mbedtls_cipher_set_iv(&decryptContext, iv.data(), iv.size()) != 0)
+            throw exception("Failed to set IV for decryption context");
+    }
+
+    void AesCipher::Decrypt(u8 *destination, u8 *source, size_t size) {
+        std::optional<std::vector<u8>> buf{};
+
+        u8 *targetDestination = [&]() {
+            if (destination == source) {
+                if (size > maxBufferSize) {
+                    buf.emplace(size);
+                    return buf->data();
+                } else {
+                    if (size > buffer.size())
+                        buffer.resize(size);
+                    return buffer.data();
+                }
+            }
+            return destination;
+        }();
+
+        mbedtls_cipher_reset(&decryptContext);
+
+        size_t outputSize{};
+        if (mbedtls_cipher_get_cipher_mode(&decryptContext) == MBEDTLS_MODE_XTS) {
+            mbedtls_cipher_update(&decryptContext, source, size, targetDestination, &outputSize);
+        } else {
+            u32 blockSize{mbedtls_cipher_get_block_size(&decryptContext)};
+
+            for (size_t offset{}; offset < size; offset += blockSize) {
+                size_t length{size - offset > blockSize ? blockSize : size - offset};
+                mbedtls_cipher_update(&decryptContext, source + offset, length, targetDestination + offset, &outputSize);
+            }
+        }
+
+        if (buf)
+            std::memcpy(destination, buf->data(), size);
+        else if (source == destination)
+            std::memcpy(destination, buffer.data(), size);
+    }
+
+    void AesCipher::XtsDecrypt(u8 *destination, u8 *source, size_t size, size_t sector, size_t sectorSize) {
+        if (size % sectorSize)
+            throw exception("Size must be multiple of sector size");
+
+        for (size_t i{}; i < size; i += sectorSize) {
+            SetIV(GetTweak(sector++));
+            Decrypt(destination + i, source + i, sectorSize);
+        }
+    }
+}

app/src/main/cpp/skyline/crypto/aes_cipher.h

@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: MPL-2.0
+// Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)
+
+#pragma once
+
+#include <array>
+#include <span>
+#include <mbedtls/cipher.h>
+#include <common.h>
+
+namespace skyline::crypto {
+    /**
+     * @brief Wrapper for mbedtls for AES decryption using a cipher
+     */
+    class AesCipher {
+      private:
+        mbedtls_cipher_context_t decryptContext;
+
+        /**
+         * @brief Buffer should grow bigger than 1 MiB
+         */
+        static constexpr size_t maxBufferSize = 1024 * 1024;
+
+        /**
+         * @brief Buffer declared as class variable to avoid constant memory allocation
+         */
+        std::vector<u8> buffer;
+
+        /**
+         * @brief Calculates IV for XTS, basically just big to little endian conversion.
+         */
+        inline static std::array<u8, 0x10> GetTweak(size_t sector) {
+            std::array<u8, 0x10> tweak{};
+            size_t le{__builtin_bswap64(sector)};
+            std::memcpy(tweak.data() + 8, &le, 8);
+            return tweak;
+        }
+
+      public:
+        AesCipher(std::span<u8> key, mbedtls_cipher_type_t type);
+
+        ~AesCipher();
+
+        /**
+         * @brief Sets initilization vector
+         */
+        void SetIV(const std::array<u8, 0x10> &iv);
+
+        /**
+         * @note destination and source can be the same
+         */
+        void Decrypt(u8 *destination, u8 *source, size_t size);
+
+        /**
+         * @brief Decrypts data and writes back to it
+         */
+        inline void Decrypt(std::span<u8> data) {
+            Decrypt(data.data(), data.data(), data.size());
+        }
+
+        /**
+         * @brief Decrypts data with XTS. IV will get calculated with the given sector
+         */
+        void XtsDecrypt(u8 *destination, u8 *source, size_t size, size_t sector, size_t sectorSize);
+
+        /**
+         * @brief Decrypts data with XTS and writes back to it
+         */
+        inline void XtsDecrypt(std::span<u8> data, size_t sector, size_t sectorSize) {
+            XtsDecrypt(data.data(), data.data(), data.size(), sector, sectorSize);
+        }
+    };
+}

app/src/main/cpp/skyline/crypto/key_store.cpp

@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: MPL-2.0
+// Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)
+
+#include <functional>
+#include <vfs/os_filesystem.h>
+#include "key_store.h"
+
+namespace skyline::crypto {
+    KeyStore::KeyStore(const std::string &rootPath) {
+        vfs::OsFileSystem root(rootPath);
+        if (root.FileExists("title.keys"))
+            ReadPairs(root.OpenFile("title.keys"), &KeyStore::PopulateTitleKeys);
+        if (root.FileExists("prod.keys"))
+            ReadPairs(root.OpenFile("prod.keys"), &KeyStore::PopulateKeys);
+    }
+
+    void KeyStore::ReadPairs(const std::shared_ptr<vfs::Backing> &backing, ReadPairsCallback callback) {
+        std::vector<char> fileContent(backing->size);
+        backing->Read(fileContent.data(), 0, fileContent.size());
+
+        auto lineStart{fileContent.begin()};
+        std::vector<char>::iterator lineEnd;
+        while ((lineEnd = std::find(lineStart, fileContent.end(), '\n')) != fileContent.end()) {
+            auto keyEnd{std::find(lineStart, lineEnd, '=')};
+            if (keyEnd == lineEnd) {
+                throw exception("Invalid key file");
+            }
+
+            std::string_view key(&*lineStart, keyEnd - lineStart);
+            std::string_view value(&*(keyEnd + 1), lineEnd - keyEnd - 1);
+            (this->*callback)(key, value);
+
+            lineStart = lineEnd + 1;
+        }
+    }
+
+    void KeyStore::PopulateTitleKeys(std::string_view keyName, std::string_view value) {
+        Key128 key{util::HexStringToArray<16>(keyName)};
+        Key128 valueArray{util::HexStringToArray<16>(value)};
+        titleKeys.insert({std::move(key), std::move(valueArray)});
+    }
+
+    void KeyStore::PopulateKeys(std::string_view keyName, std::string_view value) {
+        {
+            auto it{key256Names.find(keyName)};
+            if (it != key256Names.end()) {
+                it->second = headerKey = util::HexStringToArray<32>(value);
+                return;
+            }
+        }
+
+        if (keyName.size() > 2) {
+            auto it = indexedKey128Names.find(keyName.substr(0, keyName.size() - 2));
+            if (it != indexedKey128Names.end()) {
+                size_t index{std::stoul(std::string(keyName.substr(it->first.size())), nullptr, 16)};
+                it->second[index] = util::HexStringToArray<16>(value);
+            }
+        }
+    }
+}

app/src/main/cpp/skyline/crypto/key_store.h

@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: MPL-2.0
+// Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)
+
+#pragma once
+
+#include <array>
+#include <vfs/backing.h>
+#include "common.h"
+
+namespace skyline::crypto {
+    /**
+     * @brief The KeyStore class looks for title.keys and prod.keys files in rootPath
+     * @note Both files are created on kotlin side, prod.keys contains keys that are used to decrypt ROMs and title key, decrypted title keys are used for ctr backing.
+     */
+    class KeyStore {
+      public:
+        KeyStore(const std::string &rootPath);
+
+        using Key128 = std::array<u8, 16>;
+        using Key256 = std::array<u8, 32>;
+        using IndexedKeys128 = std::array<std::optional<Key128>, 20>;
+
+        std::optional<Key256> headerKey;
+
+        IndexedKeys128 titleKek;
+        IndexedKeys128 areaKeyApplication;
+        IndexedKeys128 areaKeyOcean;
+        IndexedKeys128 areaKeySystem;
+      private:
+        std::map<Key128, Key128> titleKeys;
+
+        std::unordered_map<std::string_view, std::optional<Key256> &> key256Names{
+            {"header_key", headerKey}
+        };
+
+        std::unordered_map<std::string_view, IndexedKeys128 &> indexedKey128Names{
+            {"titlekek_", titleKek},
+            {"key_area_key_application_", areaKeyApplication},
+            {"key_area_key_ocean_", areaKeyOcean},
+            {"key_area_key_system_", areaKeySystem}
+        };
+
+        using ReadPairsCallback = void (skyline::crypto::KeyStore::*)(std::string_view, std::string_view);
+
+        void ReadPairs(const std::shared_ptr<vfs::Backing> &backing, ReadPairsCallback callback);
+
+        void PopulateTitleKeys(std::string_view keyName, std::string_view value);
+
+        void PopulateKeys(std::string_view keyName, std::string_view value);
+
+      public:
+        inline std::optional<Key128> GetTitleKey(const Key128 &title) {
+            auto it{titleKeys.find(title)};
+            if (it == titleKeys.end())
+                return std::nullopt;
+            return it->second;
+        }
+    };
+}

app/src/main/cpp/skyline/loader/loader.h

@@ -20,6 +20,29 @@ namespace skyline::loader {
         NSP, //!< The NSP format from "nspwn" exploit: https://switchbrew.org/wiki/Switch_System_Flaws
     };
 
+    /**
+     * @brief This enumerates all possible results when parsing ROM files
+     * @note This needs to be synchronized with emu.skyline.loader.LoaderResult
+     */
+    enum class LoaderResult : int8_t {
+        Success,
+        ParsingError,
+        MissingHeaderKey,
+        MissingTitleKey,
+        MissingTitleKek,
+        MissingKeyArea
+    };
+
+    /**
+     * @brief An exception used specifically for errors related to loaders, it's used to communicate errors to the Kotlin-side of the loader
+     */
+    class loader_exception : public exception {
+      public:
+        const LoaderResult error;
+
+        loader_exception(LoaderResult error, const std::string &message = "No message") : exception("Loader exception {}: {}", error, message), error(error) {}
+    };
+
     /**
      * @brief The Loader class provides an abstract interface for ROM loaders
      */

app/src/main/cpp/skyline/loader/nca.cpp

@@ -8,7 +8,7 @@
 #include "nca.h"
 
 namespace skyline::loader {
-    NcaLoader::NcaLoader(const std::shared_ptr<vfs::Backing> &backing) : nca(backing) {
+    NcaLoader::NcaLoader(const std::shared_ptr<vfs::Backing> &backing, const std::shared_ptr<crypto::KeyStore> &keyStore) : nca(backing, keyStore) {
         if (nca.exeFs == nullptr)
             throw exception("Only NCAs with an ExeFS can be loaded directly");
     }

app/src/main/cpp/skyline/loader/nca.h

@@ -5,6 +5,7 @@
 
 #include <common.h>
 #include <vfs/nca.h>
+#include <crypto/key_store.h>
 #include "loader.h"
 
 namespace skyline::loader {
@@ -16,7 +17,7 @@ namespace skyline::loader {
         vfs::NCA nca; //!< The backing NCA of the loader
 
       public:
-        NcaLoader(const std::shared_ptr<vfs::Backing> &backing);
+        NcaLoader(const std::shared_ptr<vfs::Backing> &backing, const std::shared_ptr<crypto::KeyStore> &keyStore);
 
         /**
          * @brief This loads an ExeFS into memory

app/src/main/cpp/skyline/loader/nsp.cpp

@@ -5,20 +5,22 @@
 #include "nsp.h"
 
 namespace skyline::loader {
-    NspLoader::NspLoader(const std::shared_ptr<vfs::Backing> &backing) : nsp(std::make_shared<vfs::PartitionFileSystem>(backing)) {
+    NspLoader::NspLoader(const std::shared_ptr<vfs::Backing> &backing, const std::shared_ptr<crypto::KeyStore> &keyStore) : nsp(std::make_shared<vfs::PartitionFileSystem>(backing)) {
-        auto root = nsp->OpenDirectory("", {false, true});
+        auto root{nsp->OpenDirectory("", {false, true})};
 
         for (const auto &entry : root->Read()) {
             if (entry.name.substr(entry.name.find_last_of(".") + 1) != "nca")
                 continue;
 
             try {
-                auto nca = vfs::NCA(nsp->OpenFile(entry.name));
+                auto nca{vfs::NCA(nsp->OpenFile(entry.name), keyStore)};
 
                 if (nca.contentType == vfs::NcaContentType::Program && nca.romFs != nullptr && nca.exeFs != nullptr)
                     programNca = std::move(nca);
                 else if (nca.contentType == vfs::NcaContentType::Control && nca.romFs != nullptr)
                     controlNca = std::move(nca);
+            } catch (const loader_exception &e) {
+                throw loader_exception(e.error);
             } catch (const std::exception &e) {
                 continue;
             }
@@ -40,7 +42,7 @@ namespace skyline::loader {
         if (romFs == nullptr)
             return std::vector<u8>();
 
-        auto root = controlRomFs->OpenDirectory("", {false, true});
+        auto root{controlRomFs->OpenDirectory("", {false, true})};
         std::shared_ptr<vfs::Backing> icon;
 
         // Use the first icon file available

app/src/main/cpp/skyline/loader/nsp.h

@@ -7,6 +7,7 @@
 #include <vfs/nca.h>
 #include <vfs/rom_filesystem.h>
 #include <vfs/partition_filesystem.h>
+#include <crypto/key_store.h>
 #include "loader.h"
 
 namespace skyline::loader {
@@ -21,7 +22,7 @@ namespace skyline::loader {
         std::optional<vfs::NCA> controlNca; //!< The main control NCA within the NSP
 
       public:
-        NspLoader(const std::shared_ptr<vfs::Backing> &backing);
+        NspLoader(const std::shared_ptr<vfs::Backing> &backing, const std::shared_ptr<crypto::KeyStore> &keyStore);
 
         std::vector<u8> GetIcon();
 

app/src/main/cpp/skyline/os.cpp

@@ -13,16 +13,17 @@ namespace skyline::kernel {
     OS::OS(std::shared_ptr<JvmManager> &jvmManager, std::shared_ptr<Logger> &logger, std::shared_ptr<Settings> &settings, const std::string &appFilesPath) : state(this, process, jvmManager, settings, logger), memory(state), serviceManager(state), appFilesPath(appFilesPath) {}
 
     void OS::Execute(int romFd, loader::RomFormat romType) {
-        auto romFile = std::make_shared<vfs::OsBacking>(romFd);
+        auto romFile{std::make_shared<vfs::OsBacking>(romFd)};
+        auto keyStore{std::make_shared<crypto::KeyStore>(appFilesPath)};
 
         if (romType == loader::RomFormat::NRO) {
             state.loader = std::make_shared<loader::NroLoader>(romFile);
         } else if (romType == loader::RomFormat::NSO) {
             state.loader = std::make_shared<loader::NsoLoader>(romFile);
         } else if (romType == loader::RomFormat::NCA) {
-            state.loader = std::make_shared<loader::NcaLoader>(romFile);
+            state.loader = std::make_shared<loader::NcaLoader>(romFile, keyStore);
         } else if (romType == loader::RomFormat::NSP) {
-            state.loader = std::make_shared<loader::NspLoader>(romFile);
+            state.loader = std::make_shared<loader::NspLoader>(romFile, keyStore);
         } else {
             throw exception("Unsupported ROM extension.");
         }
@@ -36,16 +37,16 @@ namespace skyline::kernel {
     }
 
     std::shared_ptr<type::KProcess> OS::CreateProcess(u64 entry, u64 argument, size_t stackSize) {
-        auto stack = std::make_shared<type::KSharedMemory>(state, memory.stack.address, stackSize, memory::Permission{true, true, false}, memory::states::Stack, MAP_NORESERVE | MAP_STACK, true);
+        auto stack{std::make_shared<type::KSharedMemory>(state, memory.stack.address, stackSize, memory::Permission{true, true, false}, memory::states::Stack, MAP_NORESERVE | MAP_STACK, true)};
         stack->guest = stack->kernel;
 
         if (mprotect(reinterpret_cast<void *>(stack->guest.address), PAGE_SIZE, PROT_NONE))
             throw exception("Failed to create guard pages");
 
-        auto tlsMem = std::make_shared<type::KSharedMemory>(state, 0, (sizeof(ThreadContext) + (PAGE_SIZE - 1)) & ~(PAGE_SIZE - 1), memory::Permission{true, true, false}, memory::states::Reserved);
+        auto tlsMem{std::make_shared<type::KSharedMemory>(state, 0, (sizeof(ThreadContext) + (PAGE_SIZE - 1)) & ~(PAGE_SIZE - 1), memory::Permission{true, true, false}, memory::states::Reserved)};
         tlsMem->guest = tlsMem->kernel;
 
-        auto pid = clone(reinterpret_cast<int (*)(void *)>(&guest::GuestEntry), reinterpret_cast<void *>(stack->guest.address + stackSize), CLONE_FILES | CLONE_FS | CLONE_SETTLS | SIGCHLD, reinterpret_cast<void *>(entry), nullptr, reinterpret_cast<void *>(tlsMem->guest.address));
+        auto pid{clone(reinterpret_cast<int (*)(void *)>(&guest::GuestEntry), reinterpret_cast<void *>(stack->guest.address + stackSize), CLONE_FILES | CLONE_FS | CLONE_SETTLS | SIGCHLD, reinterpret_cast<void *>(entry), nullptr, reinterpret_cast<void *>(tlsMem->guest.address))};
         if (pid == -1)
             throw exception("Call to clone() has failed: {}", strerror(errno));
 

app/src/main/cpp/skyline/vfs/ctr_encrypted_backing.cpp

@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: MPL-2.0
+// Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)
+
+#include "ctr_encrypted_backing.h"
+
+namespace skyline::vfs {
+    constexpr size_t SectorSize = 0x10;
+
+    CtrEncryptedBacking::CtrEncryptedBacking(crypto::KeyStore::Key128 &ctr, crypto::KeyStore::Key128 &key, const std::shared_ptr<Backing> &backing, size_t baseOffset) : Backing({true, false, false}), ctr(ctr), cipher(key, MBEDTLS_CIPHER_AES_128_CTR), backing(backing), baseOffset(baseOffset) {}
+
+    void CtrEncryptedBacking::UpdateCtr(u64 offset) {
+        offset >>= 4;
+        size_t le{__builtin_bswap64(offset)};
+        std::memcpy(ctr.data() + 8, &le, 8);
+        cipher.SetIV(ctr);
+    }
+
+    size_t CtrEncryptedBacking::Read(u8 *output, size_t offset, size_t size) {
+        if (size == 0)
+            return 0;
+
+        size_t sectorOffset{offset % SectorSize};
+        if (sectorOffset == 0) {
+            UpdateCtr(baseOffset + offset);
+            size_t read{backing->Read(output, offset, size)};
+            if (read != size)
+                return 0;
+            cipher.Decrypt({output, size});
+            return size;
+        }
+
+        size_t sectorStart{offset - sectorOffset};
+        std::vector<u8> blockBuf(SectorSize);
+        size_t read{backing->Read(blockBuf.data(), sectorStart, SectorSize)};
+        if (read != SectorSize)
+            return 0;
+        UpdateCtr(baseOffset + sectorStart);
+        cipher.Decrypt(blockBuf);
+        if (size + sectorOffset < SectorSize) {
+            std::memcpy(output, blockBuf.data() + sectorOffset, size);
+            return size;
+        }
+
+        size_t readInBlock{SectorSize - sectorOffset};
+        std::memcpy(output, blockBuf.data() + sectorOffset, readInBlock);
+        return readInBlock + Read(output + readInBlock, offset + readInBlock, size - readInBlock);
+    }
+}

app/src/main/cpp/skyline/vfs/ctr_encrypted_backing.h

@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: MPL-2.0
+// Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)
+
+#pragma once
+
+#include <crypto/aes_cipher.h>
+#include <crypto/key_store.h>
+#include "backing.h"
+
+namespace skyline::vfs {
+    /**
+     * @brief This backing is used to decrypt AES-CTR data
+     */
+    class CtrEncryptedBacking : public Backing {
+      private:
+        crypto::KeyStore::Key128 ctr;
+
+        crypto::AesCipher cipher;
+
+        std::shared_ptr<Backing> backing;
+
+        /**
+         * @brief Offset of file is used to calculate the IV
+         */
+        size_t baseOffset;
+
+        /**
+         * @brief Calculates IV based on the offset
+         */
+        void UpdateCtr(u64 offset);
+
+      public:
+        CtrEncryptedBacking(crypto::KeyStore::Key128 &ctr, crypto::KeyStore::Key128 &key, const std::shared_ptr<Backing> &backing, size_t baseOffset);
+
+        size_t Read(u8 *output, size_t offset, size_t size) override;
+    };
+}

app/src/main/cpp/skyline/vfs/nca.cpp

@@ -1,6 +1,9 @@
 // SPDX-License-Identifier: MPL-2.0
 // Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)
 
+#include <crypto/aes_cipher.h>
+#include <loader/loader.h>
+#include "ctr_encrypted_backing.h"
 #include "region_backing.h"
 #include "partition_filesystem.h"
 #include "nca.h"
@@ -8,17 +11,31 @@
 #include "directory.h"
 
 namespace skyline::vfs {
-    NCA::NCA(const std::shared_ptr<vfs::Backing> &backing) : backing(backing) {
+    using namespace loader;
+
+    NCA::NCA(const std::shared_ptr<vfs::Backing> &backing, const std::shared_ptr<crypto::KeyStore> &keyStore) : backing(backing), keyStore(keyStore) {
         backing->Read(&header);
 
-        if (header.magic != util::MakeMagic<u32>("NCA3"))
+        if (header.magic != util::MakeMagic<u32>("NCA3")) {
-            throw exception("Attempting to load an encrypted or invalid NCA");
+            if (!keyStore->headerKey)
+                throw loader_exception(LoaderResult::MissingHeaderKey);
+
+            crypto::AesCipher cipher(*keyStore->headerKey, MBEDTLS_CIPHER_AES_128_XTS);
+
+            cipher.XtsDecrypt({reinterpret_cast<u8 *>(&header), sizeof(NcaHeader)}, 0, 0x200);
+
+            // Check if decryption was successful
+            if (header.magic != util::MakeMagic<u32>("NCA3"))
+                throw loader_exception(LoaderResult::ParsingError);
+            encrypted = true;
+        }
 
         contentType = header.contentType;
+        rightsIdEmpty = header.rightsId == crypto::KeyStore::Key128{};
 
-        for (size_t i = 0; i < header.sectionHeaders.size(); i++) {
+        for (size_t i{}; i < header.sectionHeaders.size(); i++) {
-            auto &sectionHeader = header.sectionHeaders.at(i);
+            auto &sectionHeader{header.sectionHeaders.at(i)};
-            auto &sectionEntry = header.fsEntries.at(i);
+            auto &sectionEntry{header.fsEntries.at(i)};
 
             if (sectionHeader.fsType == NcaSectionFsType::PFS0 && sectionHeader.hashType == NcaSectionHashType::HierarchicalSha256)
                 ReadPfs0(sectionHeader, sectionEntry);
@@ -27,11 +44,11 @@ namespace skyline::vfs {
         }
     }
 
-    void NCA::ReadPfs0(const NcaSectionHeader &header, const NcaFsEntry &entry) {
+    void NCA::ReadPfs0(const NcaSectionHeader &sectionHeader, const NcaFsEntry &entry) {
-        size_t offset = static_cast<size_t>(entry.startOffset) * constant::MediaUnitSize + header.sha256HashInfo.pfs0Offset;
+        size_t offset{static_cast<size_t>(entry.startOffset) * constant::MediaUnitSize + sectionHeader.sha256HashInfo.pfs0Offset};
-        size_t size = constant::MediaUnitSize * static_cast<size_t>(entry.endOffset - entry.startOffset);
+        size_t size{constant::MediaUnitSize * static_cast<size_t>(entry.endOffset - entry.startOffset)};
 
-        auto pfs = std::make_shared<PartitionFileSystem>(std::make_shared<RegionBacking>(backing, offset, size));
+        auto pfs{std::make_shared<PartitionFileSystem>(CreateBacking(sectionHeader, std::make_shared<RegionBacking>(backing, offset, size), offset))};
 
         if (contentType == NcaContentType::Program) {
             // An ExeFS must always contain an NPDM and a main NSO, whereas the logo section will always contain a logo and a startup movie
@@ -44,10 +61,95 @@ namespace skyline::vfs {
         }
     }
 
-    void NCA::ReadRomFs(const NcaSectionHeader &header, const NcaFsEntry &entry) {
+    void NCA::ReadRomFs(const NcaSectionHeader &sectionHeader, const NcaFsEntry &entry) {
-        size_t offset = static_cast<size_t>(entry.startOffset) * constant::MediaUnitSize + header.integrityHashInfo.levels.back().offset;
+        size_t offset{static_cast<size_t>(entry.startOffset) * constant::MediaUnitSize + sectionHeader.integrityHashInfo.levels.back().offset};
-        size_t size = header.integrityHashInfo.levels.back().size;
+        size_t size{sectionHeader.integrityHashInfo.levels.back().size};
 
-        romFs = std::make_shared<RegionBacking>(backing, offset, size);
+        romFs = CreateBacking(sectionHeader, std::make_shared<RegionBacking>(backing, offset, size), offset);
+    }
+
+    std::shared_ptr<Backing> NCA::CreateBacking(const NcaSectionHeader &sectionHeader, std::shared_ptr<Backing> rawBacking, size_t offset) {
+        if (!encrypted)
+            return rawBacking;
+
+        switch (sectionHeader.encryptionType) {
+            case NcaSectionEncryptionType::None:
+                return rawBacking;
+            case NcaSectionEncryptionType::CTR:
+            case NcaSectionEncryptionType::BKTR: {
+                auto key{!rightsIdEmpty ? GetTitleKey() : GetKeyAreaKey(sectionHeader.encryptionType)};
+
+                std::array<u8, 0x10> ctr{};
+                u32 secureValueLE{__builtin_bswap32(sectionHeader.secureValue)};
+                u32 generationLE{__builtin_bswap32(sectionHeader.generation)};
+                std::memcpy(ctr.data(), &secureValueLE, 4);
+                std::memcpy(ctr.data() + 4, &generationLE, 4);
+
+                return std::make_shared<CtrEncryptedBacking>(ctr, key, std::move(rawBacking), offset);
+            }
+            default:
+                return nullptr;
+        }
+    }
+
+    u8 NCA::GetKeyGeneration() {
+        u8 legacyGen{static_cast<u8>(header.legacyKeyGenerationType)};
+        u8 gen{static_cast<u8>(header.keyGenerationType)};
+        gen = std::max<u8>(legacyGen, gen);
+        return gen > 0 ? gen - 1 : gen;
+    }
+
+    crypto::KeyStore::Key128 NCA::GetTitleKey() {
+        u8 keyGeneration{GetKeyGeneration()};
+
+        auto titleKey{keyStore->GetTitleKey(header.rightsId)};
+        auto &titleKek{keyStore->titleKek[keyGeneration]};
+
+        if (!titleKey)
+            throw loader_exception(LoaderResult::MissingTitleKey);
+        if (!titleKek)
+            throw loader_exception(LoaderResult::MissingTitleKek);
+
+        crypto::AesCipher cipher(*titleKek, MBEDTLS_CIPHER_AES_128_ECB);
+        cipher.Decrypt(*titleKey);
+        return *titleKey;
+    }
+
+    crypto::KeyStore::Key128 NCA::GetKeyAreaKey(NCA::NcaSectionEncryptionType type) {
+        auto keyArea{[&](crypto::KeyStore::IndexedKeys128 &keys) {
+            u8 keyGeneration{GetKeyGeneration()};
+
+            auto &keyArea{keys[keyGeneration]};
+
+            if (!keyArea)
+                throw loader_exception(LoaderResult::MissingKeyArea);
+
+            size_t keyAreaIndex;
+            switch (type) {
+                case NcaSectionEncryptionType::XTS:
+                    keyAreaIndex = 0;
+                    break;
+                case NcaSectionEncryptionType::CTR:
+                case NcaSectionEncryptionType::BKTR:
+                    keyAreaIndex = 2;
+                    break;
+                default:
+                    throw exception("Unsupported NcaSectionEncryptionType");
+            }
+
+            crypto::KeyStore::Key128 decryptedKeyArea;
+            crypto::AesCipher cipher(*keyArea, MBEDTLS_CIPHER_AES_128_ECB);
+            cipher.Decrypt(decryptedKeyArea.data(), header.encryptedKeyArea[keyAreaIndex].data(), decryptedKeyArea.size());
+            return decryptedKeyArea;
+        }};
+
+        switch (header.keyAreaEncryptionKeyType) {
+            case NcaKeyAreaEncryptionKeyType::Application:
+                return keyArea(keyStore->areaKeyApplication);
+            case NcaKeyAreaEncryptionKeyType::Ocean:
+                return keyArea(keyStore->areaKeyOcean);
+            case NcaKeyAreaEncryptionKeyType::System:
+                return keyArea(keyStore->areaKeySystem);
+        }
     }
 }

app/src/main/cpp/skyline/vfs/nca.h

@@ -4,6 +4,8 @@
 #pragma once
 
 #include <array>
+#include <crypto/key_store.h>
+#include <crypto/aes_cipher.h>
 #include "filesystem.h"
 
 namespace skyline {
@@ -195,10 +197,21 @@ namespace skyline {
             static_assert(sizeof(NcaHeader) == 0xC00);
 
             std::shared_ptr<Backing> backing; //!< The backing for the NCA
+            std::shared_ptr<crypto::KeyStore> keyStore;
+            bool encrypted{false};
+            bool rightsIdEmpty;
 
-            void ReadPfs0(const NcaSectionHeader &header, const NcaFsEntry &entry);
+            void ReadPfs0(const NcaSectionHeader &sectionHeader, const NcaFsEntry &entry);
 
-            void ReadRomFs(const NcaSectionHeader &header, const NcaFsEntry &entry);
+            void ReadRomFs(const NcaSectionHeader &sectionHeader, const NcaFsEntry &entry);
+
+            std::shared_ptr<Backing> CreateBacking(const NcaSectionHeader &sectionHeader, std::shared_ptr<Backing> rawBacking, size_t offset);
+
+            u8 GetKeyGeneration();
+
+            crypto::KeyStore::Key128 GetTitleKey();
+
+            crypto::KeyStore::Key128 GetKeyAreaKey(NcaSectionEncryptionType type);
 
           public:
             std::shared_ptr<FileSystem> exeFs; //!< The PFS0 filesystem for this NCA's ExeFS section
@@ -207,7 +220,7 @@ namespace skyline {
             std::shared_ptr<Backing> romFs; //!< The backing for this NCA's RomFS section
             NcaContentType contentType; //!< The content type of the NCA
 
-            NCA(const std::shared_ptr<vfs::Backing> &backing);
+            NCA(const std::shared_ptr<vfs::Backing> &backing, const std::shared_ptr<crypto::KeyStore> &keyStore);
         };
     }
 }

app/src/main/cpp/skyline/vfs/os_filesystem.cpp

@@ -10,7 +10,7 @@
 #include "os_filesystem.h"
 
 namespace skyline::vfs {
-    OsFileSystem::OsFileSystem(const std::string &basePath) : FileSystem(), basePath(std::move(basePath)) {
+    OsFileSystem::OsFileSystem(const std::string &basePath) : FileSystem(), basePath(basePath) {
         if (!DirectoryExists(basePath))
             if (!CreateDirectory(basePath, true))
                 throw exception("Error creating the OS filesystem backing directory");

app/src/main/cpp/skyline/vfs/partition_filesystem.cpp

@@ -19,12 +19,13 @@ namespace skyline::vfs {
         size_t stringTableOffset = sizeof(FsHeader) + (header.numFiles * entrySize);
         fileDataOffset = stringTableOffset + header.stringTableSize;
 
-        std::vector<char> stringTable(header.stringTableSize);
+        std::vector<char> stringTable(header.stringTableSize + 1);
         backing->Read(stringTable.data(), stringTableOffset, header.stringTableSize);
+        stringTable[header.stringTableSize] = 0;
 
-        for (u32 i = 0; i < header.numFiles; i++) {
+        for (u32 entryOffset{sizeof(FsHeader)}; entryOffset < header.numFiles * entrySize; entryOffset += entrySize) {
-            PartitionFileEntry entry{};
+            PartitionFileEntry entry;
-            backing->Read(&entry, sizeof(FsHeader) + i * entrySize);
+            backing->Read(&entry, entryOffset);
 
             std::string name(&stringTable[entry.stringTableOffset]);
             fileMap.emplace(name, std::move(entry));

app/src/main/cpp/skyline/vfs/region_backing.h

@@ -12,7 +12,7 @@ namespace skyline::vfs {
     class RegionBacking : public Backing {
       private:
         std::shared_ptr<vfs::Backing> backing; //!< The parent backing
-        size_t offset; //!< The offset of the region in the parent backing
+        size_t baseOffset; //!< The offset of the region in the parent backing
 
       public:
         /**
@@ -20,7 +20,7 @@ namespace skyline::vfs {
          * @param offset The offset of the region start within the parent backing
          * @param size The size of the region in the parent backing
          */
-        RegionBacking(const std::shared_ptr<vfs::Backing> &backing, size_t offset, size_t size, Mode mode = {true, false, false}) : Backing(mode, size), backing(backing), offset(offset) {};
+        RegionBacking(const std::shared_ptr<vfs::Backing> &backing, size_t offset, size_t size, Mode mode = {true, false, false}) : Backing(mode, size), backing(backing), baseOffset(offset) {};
 
         inline size_t Read(u8 *output, size_t offset, size_t size) {
             if (!mode.read)
@@ -28,7 +28,7 @@ namespace skyline::vfs {
 
             size = std::min(offset + size, this->size) - offset;
 
-            return backing->Read(output, this->offset + offset, size);
+            return backing->Read(output, baseOffset + offset, size);
         }
     };
 }

app/src/main/java/emu/skyline/AppDialog.kt

@@ -20,14 +20,28 @@ import androidx.core.graphics.drawable.toBitmap
 import com.google.android.material.bottomsheet.BottomSheetBehavior
 import com.google.android.material.bottomsheet.BottomSheetDialogFragment
 import emu.skyline.data.AppItem
+import emu.skyline.loader.LoaderResult
 import kotlinx.android.synthetic.main.app_dialog.*
 
 /**
  * This dialog is used to show extra game metadata and provide extra options such as pinning the game to the home screen
- *
- * @param item This is used to hold the [AppItem] between instances
  */
-class AppDialog(val item : AppItem) : BottomSheetDialogFragment() {
+class AppDialog : BottomSheetDialogFragment() {
+    companion object {
+        /**
+         * @param item This is used to hold the [AppItem] between instances
+         */
+        fun newInstance(item : AppItem) : AppDialog {
+            val args = Bundle()
+            args.putSerializable("item", item)
+
+            val fragment = AppDialog()
+            fragment.arguments = args
+            return fragment
+        }
+    }
+
+    private lateinit var item : AppItem
 
     /**
      * This inflates the layout of the dialog after initial view creation
@@ -36,6 +50,12 @@ class AppDialog(val item : AppItem) : BottomSheetDialogFragment() {
         return requireActivity().layoutInflater.inflate(R.layout.app_dialog, container)
     }
 
+    override fun onCreate(savedInstanceState : Bundle?) {
+        super.onCreate(savedInstanceState)
+
+        item = arguments!!.getSerializable("item") as AppItem
+    }
+
     /**
      * This expands the bottom sheet so that it's fully visible and map the B button to back
      */
@@ -64,13 +84,11 @@ class AppDialog(val item : AppItem) : BottomSheetDialogFragment() {
 
         game_icon.setImageBitmap(item.icon ?: missingIcon)
         game_title.text = item.title
-        game_subtitle.text = item.subTitle ?: getString(R.string.metadata_missing)
+        game_subtitle.text = item.subTitle ?: item.loaderResultString(requireContext())
 
+        game_play.isEnabled = item.loaderResult == LoaderResult.Success
         game_play.setOnClickListener {
-            val intent = Intent(activity, EmulationActivity::class.java)
+            startActivity(Intent(activity, EmulationActivity::class.java).apply { data = item.uri })
-            intent.data = item.uri
-
-            startActivity(intent)
         }
 
         val shortcutManager = requireActivity().getSystemService(ShortcutManager::class.java)

app/src/main/java/emu/skyline/EmulationActivity.kt

@@ -21,6 +21,10 @@ import java.io.File
 import kotlin.math.abs
 
 class EmulationActivity : AppCompatActivity(), SurfaceHolder.Callback, View.OnTouchListener {
+    companion object {
+        private val Tag = EmulationActivity::class.java.name
+    }
+
     init {
         System.loadLibrary("skyline") // libskyline.so
     }
@@ -287,7 +291,7 @@ class EmulationActivity : AppCompatActivity(), SurfaceHolder.Callback, View.OnTo
      * This sets [surface] to [holder].surface and passes it into libskyline
      */
     override fun surfaceCreated(holder : SurfaceHolder) {
-        Log.d("surfaceCreated", "Holder: $holder")
+        Log.d(Tag, "surfaceCreated Holder: $holder")
         surface = holder.surface
         setSurface(surface)
         surfaceReady.open()
@@ -297,14 +301,14 @@ class EmulationActivity : AppCompatActivity(), SurfaceHolder.Callback, View.OnTo
      * This is purely used for debugging surface changes
      */
     override fun surfaceChanged(holder : SurfaceHolder, format : Int, width : Int, height : Int) {
-        Log.d("surfaceChanged", "Holder: $holder, Format: $format, Width: $width, Height: $height")
+        Log.d(Tag, "surfaceChanged Holder: $holder, Format: $format, Width: $width, Height: $height")
     }
 
     /**
      * This sets [surface] to null and passes it into libskyline
      */
     override fun surfaceDestroyed(holder : SurfaceHolder) {
-        Log.d("surfaceDestroyed", "Holder: $holder")
+        Log.d(Tag, "surfaceDestroyed Holder: $holder")
         surfaceReady.close()
         surface = null
         setSurface(surface)

app/src/main/java/emu/skyline/KeyReader.kt

@@ -0,0 +1,86 @@
+/*
+ * SPDX-License-Identifier: MPL-2.0
+ * Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)
+ */
+
+package emu.skyline
+
+import android.content.Context
+import android.net.Uri
+import android.util.Log
+import androidx.documentfile.provider.DocumentFile
+import java.io.File
+
+object KeyReader {
+    private val Tag = KeyReader::class.java.simpleName
+
+    enum class KeyType(val keyName : String, val fileName : String) {
+        Title("title_keys", "title.keys"), Prod("prod_keys", "prod.keys");
+
+        companion object {
+            fun parse(keyName : String) = values().first { it.keyName == keyName }
+        }
+    }
+
+    /**
+     * Reads keys file, trims and writes to internal app data storage, it makes sure file is properly formatted
+     */
+    fun import(context : Context, uri : Uri, keyType : KeyType) : Boolean {
+        Log.i(Tag, "Parsing ${keyType.name}")
+
+        if (!DocumentFile.isDocumentUri(context, uri))
+            return false
+
+        val fileName = DocumentFile.fromSingleUri(context, uri)!!.name
+        if ("keys" != fileName?.substringAfterLast('.')) return false
+
+        val tmpOutputFile = File("${context.filesDir.canonicalFile}/${keyType.fileName}.tmp")
+
+        val inputStream = context.contentResolver.openInputStream(uri)
+        val outputStream = tmpOutputFile.bufferedWriter()
+
+        val valid = inputStream!!.bufferedReader().useLines {
+            for (line in it) {
+                val pair = line.split("=")
+                if (pair.size != 2)
+                    return@useLines false
+
+                val key = pair[0].trim()
+                val value = pair[1].trim()
+                when (keyType) {
+                    KeyType.Title -> {
+                        if (key.length != 32 && !isHexString(key))
+                            return@useLines false
+                        if (value.length != 32 && !isHexString(value))
+                            return@useLines false
+                    }
+                    KeyType.Prod -> {
+                        if (!key.contains("_"))
+                            return@useLines false
+                        if (!isHexString(value))
+                            return@useLines false
+                    }
+                }
+
+                outputStream.append("$key=$value\n")
+            }
+            true
+        }
+
+        outputStream.flush()
+        outputStream.close()
+
+        if (valid)
+            tmpOutputFile.renameTo(File("${tmpOutputFile.parent}/${keyType.fileName}"))
+        return valid
+    }
+
+    private fun isHexString(str : String) : Boolean {
+        for (c in str) {
+            if (!(c in '0'..'9' || c in 'a'..'f' || c in 'A'..'F')) {
+                return false
+            }
+        }
+        return true
+    }
+}

app/src/main/java/emu/skyline/MainActivity.kt

@@ -30,16 +30,18 @@ import emu.skyline.adapter.AppAdapter
 import emu.skyline.adapter.GridLayoutSpan
 import emu.skyline.adapter.LayoutType
 import emu.skyline.data.AppItem
+import emu.skyline.loader.LoaderResult
 import emu.skyline.loader.RomFile
 import emu.skyline.loader.RomFormat
 import kotlinx.android.synthetic.main.main_activity.*
 import kotlinx.android.synthetic.main.titlebar.*
 import java.io.File
 import java.io.IOException
+import java.util.concurrent.atomic.AtomicBoolean
 import kotlin.concurrent.thread
 import kotlin.math.ceil
 
-class MainActivity : AppCompatActivity(), View.OnClickListener {
+class MainActivity : AppCompatActivity() {
     /**
      * This is used to get/set shared preferences
      */
@@ -50,8 +52,10 @@ class MainActivity : AppCompatActivity(), View.OnClickListener {
      */
     private lateinit var adapter : AppAdapter
 
+    private var reloading = AtomicBoolean()
+
     /**
-     * This adds all files in [directory] with [extension] as an entry in [adapter] using [loader] to load metadata
+     * This adds all files in [directory] with [extension] as an entry in [adapter] using [RomFile] to load metadata
      */
     private fun addEntries(extension : String, romFormat : RomFormat, directory : DocumentFile, found : Boolean = false) : Boolean {
         var foundCurrent = found
@@ -61,25 +65,16 @@ class MainActivity : AppCompatActivity(), View.OnClickListener {
                 foundCurrent = addEntries(extension, romFormat, file, foundCurrent)
             } else {
                 if (extension.equals(file.name?.substringAfterLast("."), ignoreCase = true)) {
-                    val romFd = contentResolver.openFileDescriptor(file.uri, "r")!!
+                    RomFile(this, romFormat, file.uri).let { romFile ->
-                    val romFile = RomFile(this, romFormat, romFd)
+                        val finalFoundCurrent = foundCurrent
+                        runOnUiThread {
+                            if (!finalFoundCurrent) adapter.addHeader(romFormat.name)
 
-                    if (romFile.valid()) {
+                            adapter.addItem(AppItem(romFile.appEntry))
-                        romFile.use {
-                            val entry = romFile.getAppEntry(file.uri)
-
-                            val finalFoundCurrent = foundCurrent
-                            runOnUiThread {
-                                if (!finalFoundCurrent) adapter.addHeader(romFormat.name)
-
-                                adapter.addItem(AppItem(entry))
-                            }
-
-                            foundCurrent = true
                         }
-                    }
 
-                    romFd.close()
+                        foundCurrent = true
+                    }
                 }
             }
         }
@@ -102,6 +97,7 @@ class MainActivity : AppCompatActivity(), View.OnClickListener {
             }
         }
 
+        if (reloading.getAndSet(true)) return
         thread(start = true) {
             val snackbar = Snackbar.make(coordinatorLayout, getString(R.string.searching_roms), Snackbar.LENGTH_INDEFINITE)
             runOnUiThread {
@@ -148,6 +144,8 @@ class MainActivity : AppCompatActivity(), View.OnClickListener {
                 snackbar.dismiss()
                 requestedOrientation = ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED
             }
+
+            reloading.set(false)
         }
     }
 
@@ -171,10 +169,18 @@ class MainActivity : AppCompatActivity(), View.OnClickListener {
             else -> AppCompatDelegate.MODE_NIGHT_UNSPECIFIED
         })
 
-        refresh_fab.setOnClickListener(this)
+        refresh_fab.setOnClickListener { refreshAdapter(false) }
-        settings_fab.setOnClickListener(this)
+
-        open_fab.setOnClickListener(this)
+        settings_fab.setOnClickListener { startActivityForResult(Intent(this, SettingsActivity::class.java), 3) }
-        log_fab.setOnClickListener(this)
+
+        open_fab.setOnClickListener { startActivity(Intent(this, LogActivity::class.java)) }
+
+        log_fab.setOnClickListener {
+            startActivityForResult(Intent(Intent.ACTION_OPEN_DOCUMENT).apply {
+                addCategory(Intent.CATEGORY_OPENABLE)
+                type = "*/*"
+            }, 2)
+        }
 
         setupAppList()
 
@@ -217,7 +223,7 @@ class MainActivity : AppCompatActivity(), View.OnClickListener {
 
         val layoutType = LayoutType.values()[sharedPreferences.getString("layout_type", "1")!!.toInt()]
 
-        adapter = AppAdapter(layoutType = layoutType, gridSpan = gridSpan, onClick = selectStartGame, onLongClick = selectShowGameDialog)
+        adapter = AppAdapter(layoutType = layoutType, onClick = ::selectStartGame, onLongClick = ::selectShowGameDialog)
         app_list.adapter = adapter
 
         app_list.layoutManager = when (layoutType) {
@@ -263,37 +269,15 @@ class MainActivity : AppCompatActivity(), View.OnClickListener {
         return super.onCreateOptionsMenu(menu)
     }
 
-    /**
+    private fun selectStartGame(appItem : AppItem) {
-     * This handles on-click interaction with [R.id.refresh_fab], [R.id.settings_fab], [R.id.log_fab], [R.id.open_fab]
+        if (sharedPreferences.getBoolean("select_action", false))
-     */
+            AppDialog.newInstance(appItem).show(supportFragmentManager, "game")
-    override fun onClick(view : View) {
+        else if (appItem.loaderResult == LoaderResult.Success)
-        when (view.id) {
+            startActivity(Intent(this, EmulationActivity::class.java).apply { data = appItem.uri })
-            R.id.refresh_fab -> refreshAdapter(false)
-
-            R.id.settings_fab -> startActivityForResult(Intent(this, SettingsActivity::class.java), 3)
-
-            R.id.log_fab -> startActivity(Intent(this, LogActivity::class.java))
-
-            R.id.open_fab -> {
-                val intent = Intent(Intent.ACTION_OPEN_DOCUMENT)
-                intent.addCategory(Intent.CATEGORY_OPENABLE)
-                intent.type = "*/*"
-
-                startActivityForResult(intent, 2)
-            }
-        }
     }
 
-    private val selectStartGame : (appItem : AppItem) -> Unit = {
+    private fun selectShowGameDialog(appItem : AppItem) {
-        if (sharedPreferences.getBoolean("select_action", false)) {
+        AppDialog.newInstance(appItem).show(supportFragmentManager, "game")
-            AppDialog(it).show(supportFragmentManager, "game")
-        } else {
-            startActivity(Intent(this, EmulationActivity::class.java).apply { data = it.uri })
-        }
-    }
-
-    private val selectShowGameDialog : (appItem : AppItem) -> Unit = {
-        AppDialog(it).show(supportFragmentManager, "game")
     }
 
     /**
@@ -363,8 +347,8 @@ class MainActivity : AppCompatActivity(), View.OnClickListener {
 
         val gridCardMagin = resources.getDimensionPixelSize(R.dimen.app_card_margin_half)
         when (layoutType) {
-            LayoutType.List -> app_list.setPadding(0, 0, 0, 0)
+            LayoutType.List -> app_list.post { app_list.setPadding(0, 0, 0, fab_parent.height) }
-            LayoutType.Grid, LayoutType.GridCompact -> app_list.setPadding(gridCardMagin, 0, gridCardMagin, 0)
+            LayoutType.Grid, LayoutType.GridCompact -> app_list.post { app_list.setPadding(gridCardMagin, 0, gridCardMagin, fab_parent.height) }
         }
     }
 }

app/src/main/java/emu/skyline/SettingsActivity.kt

@@ -9,10 +9,13 @@ import android.content.Intent
 import android.os.Bundle
 import android.view.KeyEvent
 import androidx.appcompat.app.AppCompatActivity
-import androidx.preference.Preference
 import androidx.preference.PreferenceFragmentCompat
+import androidx.preference.PreferenceGroup
 import emu.skyline.input.InputManager
+import emu.skyline.preference.ActivityResultDelegate
 import emu.skyline.preference.ControllerPreference
+import emu.skyline.preference.DocumentActivity
+import kotlinx.android.synthetic.main.settings_activity.*
 import kotlinx.android.synthetic.main.titlebar.*
 
 class SettingsActivity : AppCompatActivity() {
@@ -26,11 +29,6 @@ class SettingsActivity : AppCompatActivity() {
      */
     lateinit var inputManager : InputManager
 
-    /**
-     * The key of the element to force a refresh when [onActivityResult] is called
-     */
-    var refreshKey : String? = null
-
     /**
      * This initializes all of the elements in the activity and displays the settings fragment
      */
@@ -51,30 +49,27 @@ class SettingsActivity : AppCompatActivity() {
     }
 
     /**
-     * This is used to refresh the preferences after [emu.skyline.preference.FolderActivity] or [emu.skyline.input.ControllerActivity] has returned
+     * This is used to refresh the preferences after [DocumentActivity] or [emu.skyline.input.ControllerActivity] has returned
      */
     public override fun onActivityResult(requestCode : Int, resultCode : Int, data : Intent?) {
         super.onActivityResult(requestCode, resultCode, data)
 
-        refreshKey?.let {
+        preferenceFragment.delegateActivityResult(requestCode, resultCode, data)
-            inputManager.syncObjects()
-            preferenceFragment.refreshPreference(refreshKey!!)
 
-            refreshKey = null
+        settings
-        }
     }
 
     /**
-     * This fragment is used to display all of the preferences and handle refreshing the preferences
+     * This fragment is used to display all of the preferences
      */
     class PreferenceFragment : PreferenceFragmentCompat() {
+        private var requestCodeCounter = 0
+
         /**
-         * This forces refreshing a certain preference by indirectly calling [Preference.notifyChanged]
+         * Delegates activity result to all preferences which implement [ActivityResultDelegate]
          */
-        fun refreshPreference(key : String) {
+        fun delegateActivityResult(requestCode : Int, resultCode : Int, data : Intent?) {
-            val preference = preferenceManager.findPreference<Preference>(key)!!
+            preferenceScreen.delegateActivityResult(requestCode, resultCode, data)
-            preference.isSelectable = !preference.isSelectable
-            preference.isSelectable = !preference.isSelectable
         }
 
         /**
@@ -82,6 +77,25 @@ class SettingsActivity : AppCompatActivity() {
          */
         override fun onCreatePreferences(savedInstanceState : Bundle?, rootKey : String?) {
             setPreferencesFromResource(R.xml.preferences, rootKey)
+            preferenceScreen.assignActivityRequestCode()
+        }
+
+        private fun PreferenceGroup.assignActivityRequestCode() {
+            for (i in 0 until preferenceCount) {
+                when (val pref = getPreference(i)) {
+                    is PreferenceGroup -> pref.assignActivityRequestCode()
+                    is ActivityResultDelegate -> pref.requestCode = requestCodeCounter++
+                }
+            }
+        }
+
+        private fun PreferenceGroup.delegateActivityResult(requestCode : Int, resultCode : Int, data : Intent?) {
+            for (i in 0 until preferenceCount) {
+                when (val pref = getPreference(i)) {
+                    is PreferenceGroup -> pref.delegateActivityResult(requestCode, resultCode, data)
+                    is ActivityResultDelegate -> pref.onActivityResult(requestCode, resultCode, data)
+                }
+            }
         }
     }
 

app/src/main/java/emu/skyline/adapter/AppAdapter.kt

@@ -36,10 +36,9 @@ private typealias InteractionFunction = (appItem : AppItem) -> Unit
 /**
  * This adapter is used to display all found applications using their metadata
  */
-internal class AppAdapter(val layoutType : LayoutType, private val gridSpan : Int, private val onClick : InteractionFunction, private val onLongClick : InteractionFunction) : HeaderAdapter<AppItem, BaseHeader, RecyclerView.ViewHolder>() {
+internal class AppAdapter(val layoutType : LayoutType, private val onClick : InteractionFunction, private val onLongClick : InteractionFunction) : HeaderAdapter<AppItem, BaseHeader, RecyclerView.ViewHolder>() {
     private lateinit var context : Context
     private val missingIcon by lazy { ContextCompat.getDrawable(context, R.drawable.default_icon)!!.toBitmap(256, 256) }
-    private val missingString by lazy { context.getString(R.string.metadata_missing) }
 
     /**
      * This adds a header to the view with the contents of [string]
@@ -105,7 +104,7 @@ internal class AppAdapter(val layoutType : LayoutType, private val gridSpan : In
 
         if (item is AppItem && holder is ItemViewHolder) {
             holder.title.text = item.title
-            holder.subtitle.text = item.subTitle ?: missingString
+            holder.subtitle.text = item.subTitle ?: item.loaderResultString(holder.subtitle.context)
 
             holder.icon.setImageBitmap(item.icon ?: missingIcon)
 

app/src/main/java/emu/skyline/data/AppItem.kt

@@ -5,9 +5,12 @@
 
 package emu.skyline.data
 
+import android.content.Context
 import android.graphics.Bitmap
 import android.net.Uri
+import emu.skyline.R
 import emu.skyline.loader.AppEntry
+import emu.skyline.loader.LoaderResult
 
 /**
  * This class is a wrapper around [AppEntry], it is used for passing around game metadata
@@ -43,6 +46,20 @@ class AppItem(val meta : AppEntry) : BaseItem() {
     private val type : String
         get() = meta.format.name
 
+    val loaderResult get() = meta.loaderResult
+
+    fun loaderResultString(context : Context) = context.getString(when (meta.loaderResult) {
+        LoaderResult.Success -> R.string.metadata_missing
+
+        LoaderResult.ParsingError -> R.string.invalid_file
+
+        LoaderResult.MissingTitleKey -> R.string.missing_title_key
+
+        LoaderResult.MissingHeaderKey,
+        LoaderResult.MissingTitleKek,
+        LoaderResult.MissingKeyArea -> R.string.incomplete_prod_keys
+    })
+
     /**
      * The name and author is used as the key
      */

app/src/main/java/emu/skyline/input/InputManager.kt

@@ -61,23 +61,19 @@ class InputManager constructor(val context : Context) {
      * This function syncs the class with data from [file]
      */
     fun syncObjects() {
-        val fileInput = FileInputStream(file)
+        ObjectInputStream(FileInputStream(file)).use {
-        val objectInput = ObjectInputStream(fileInput)
+            @Suppress("UNCHECKED_CAST")
+            controllers = it.readObject() as HashMap<Int, Controller>
 
-        @Suppress("UNCHECKED_CAST")
+            @Suppress("UNCHECKED_CAST")
-        controllers = objectInput.readObject() as HashMap<Int, Controller>
+            eventMap = it.readObject() as HashMap<HostEvent?, GuestEvent?>
-
+        }
-        @Suppress("UNCHECKED_CAST")
-        eventMap = objectInput.readObject() as HashMap<HostEvent?, GuestEvent?>
     }
 
     /**
      * This function syncs [file] with data from the class and eliminates unused value from the map
      */
     fun syncFile() {
-        val fileOutput = FileOutputStream(file)
-        val objectOutput = ObjectOutputStream(fileOutput)
-
         for (controller in controllers.values) {
             for (button in ButtonId.values()) {
                 if (button != ButtonId.Menu && !(controller.type.buttons.contains(button) || controller.type.sticks.any { it.button == button })) {
@@ -100,9 +96,11 @@ class InputManager constructor(val context : Context) {
             }
         }
 
-        objectOutput.writeObject(controllers)
+        ObjectOutputStream(FileOutputStream(file)).use {
-        objectOutput.writeObject(eventMap)
+            it.writeObject(controllers)
+            it.writeObject(eventMap)
 
-        objectOutput.flush()
+            it.flush()
+        }
     }
 }

app/src/main/java/emu/skyline/loader/RomFile.kt

@@ -10,12 +10,7 @@ import android.content.Context
 import android.graphics.Bitmap
 import android.graphics.BitmapFactory
 import android.net.Uri
-import android.os.Build
-import android.os.ParcelFileDescriptor
 import android.provider.OpenableColumns
-import java.io.IOException
-import java.io.ObjectInputStream
-import java.io.ObjectOutputStream
 import java.io.Serializable
 import java.util.*
 
@@ -46,166 +41,81 @@ fun getRomFormat(uri : Uri, contentResolver : ContentResolver) : RomFormat {
     return RomFormat.valueOf(uriStr.substring(uriStr.lastIndexOf(".") + 1).toUpperCase(Locale.ROOT))
 }
 
+/**
+ * An enumeration of all possible results when populating [RomFile]
+ */
+enum class LoaderResult(val value : Int) {
+    Success(0),
+    ParsingError(1),
+    MissingHeaderKey(2),
+    MissingTitleKey(3),
+    MissingTitleKek(4),
+    MissingKeyArea(5);
+
+    companion object {
+        fun get(value : Int) = values().first { value == it.value }
+    }
+}
+
 /**
  * This class is used to hold an application's metadata in a serializable way
  */
-class AppEntry : Serializable {
+class AppEntry(val name : String, val author : String?, val icon : Bitmap?, val format : RomFormat, val uri : Uri, val loaderResult : LoaderResult) : Serializable {
-    /**
+    constructor(context : Context, format : RomFormat, uri : Uri, loaderResult : LoaderResult) : this(context.contentResolver.query(uri, null, null, null, null)?.use { cursor ->
-     * The name of the application
+        val nameIndex : Int = cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME)
-     */
+        cursor.moveToFirst()
-    var name : String
+        cursor.getString(nameIndex)
-
+    }!!.dropLast(format.name.length + 1), null, null, format, uri, loaderResult)
-    /**
-     * The author of the application, if it can be extracted from the metadata
-     */
-    var author : String? = null
-
-    var icon : Bitmap? = null
-
-    /**
-     * The format of the application ROM
-     */
-    var format : RomFormat
-
-    /**
-     * The URI of the application ROM
-     */
-    var uri : Uri
-
-    constructor(name : String, author : String, format : RomFormat, uri : Uri, icon : Bitmap?) {
-        this.name = name
-        this.author = author
-        this.icon = icon
-        this.format = format
-        this.uri = uri
-    }
-
-    constructor(context : Context, format : RomFormat, uri : Uri) {
-        this.name = context.contentResolver.query(uri, null, null, null, null)?.use { cursor ->
-            val nameIndex : Int = cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME)
-            cursor.moveToFirst()
-            cursor.getString(nameIndex)
-        }!!.dropLast(format.name.length + 1)
-        this.format = format
-        this.uri = uri
-    }
-
-    /**
-     * This serializes this object into an OutputStream
-     *
-     * @param output The stream to which the object is written into
-     */
-    @Throws(IOException::class)
-    private fun writeObject(output : ObjectOutputStream) {
-        output.writeUTF(name)
-        output.writeObject(format)
-        output.writeUTF(uri.toString())
-        output.writeBoolean(author != null)
-        if (author != null)
-            output.writeUTF(author)
-        output.writeBoolean(icon != null)
-        if (icon != null) {
-            @Suppress("DEPRECATION")
-            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R)
-                icon!!.compress(Bitmap.CompressFormat.WEBP_LOSSY, 100, output)
-            else
-                icon!!.compress(Bitmap.CompressFormat.WEBP, 100, output)
-        }
-    }
-
-    /**
-     * This initializes the object from an InputStream
-     *
-     * @param input The stream from which the object data is retrieved from
-     */
-    @Throws(IOException::class, ClassNotFoundException::class)
-    private fun readObject(input : ObjectInputStream) {
-        name = input.readUTF()
-        format = input.readObject() as RomFormat
-        uri = Uri.parse(input.readUTF())
-        if (input.readBoolean())
-            author = input.readUTF()
-        if (input.readBoolean())
-            icon = BitmapFactory.decodeStream(input)
-    }
 }
 
 /**
  * This class is used as interface between libskyline and Kotlin for loaders
  */
-internal class RomFile(val context : Context, val format : RomFormat, val file : ParcelFileDescriptor) : AutoCloseable {
+internal class RomFile(context : Context, format : RomFormat, uri : Uri) {
     /**
-     * This is a pointer to the corresponding C++ Loader class
+     * @note This field is filled in by native code
      */
-    var instance : Long
+    private var applicationName : String? = null
+
+    /**
+     * @note This field is filled in by native code
+     */
+    private var applicationAuthor : String? = null
+
+    /**
+     * @note This field is filled in by native code
+     */
+    private var rawIcon : ByteArray? = null
+
+    val appEntry : AppEntry
+
+    var result = LoaderResult.Success
+
+    val valid : Boolean
+        get() = result == LoaderResult.Success
 
     init {
         System.loadLibrary("skyline")
 
-        instance = initialize(format.ordinal, file.fd)
+        context.contentResolver.openFileDescriptor(uri, "r")!!.use {
+            result = LoaderResult.get(populate(format.ordinal, it.fd, context.filesDir.canonicalPath + "/"))
+        }
+
+        appEntry = applicationName?.let { name ->
+            applicationAuthor?.let { author ->
+                rawIcon?.let { icon ->
+                    AppEntry(name, author, BitmapFactory.decodeByteArray(icon, 0, icon.size), format, uri, result)
+                }
+            }
+        } ?: AppEntry(context, format, uri, result)
     }
 
     /**
-     * This allocates and initializes a new loader object
+     * Parses ROM and writes its metadata to [applicationName], [applicationAuthor] and [rawIcon]
      * @param format The format of the ROM
      * @param romFd A file descriptor of the ROM
+     * @param appFilesPath Path to internal app data storage, needed to read imported keys
      * @return A pointer to the newly allocated object, or 0 if the ROM is invalid
      */
-    private external fun initialize(format : Int, romFd : Int) : Long
+    private external fun populate(format : Int, romFd : Int, appFilesPath : String) : Int
-
-    /**
-     * @return Whether the ROM contains assets, such as an icon or author information
-     */
-    private external fun hasAssets(instance : Long) : Boolean
-
-    /**
-     * @return A ByteArray containing the application's icon as a bitmap
-     */
-    private external fun getIcon(instance : Long) : ByteArray
-
-    /**
-     * @return A String containing the name of the application
-     */
-    private external fun getApplicationName(instance : Long) : String
-
-    /**
-     * @return A String containing the publisher of the application
-     */
-    private external fun getApplicationPublisher(instance : Long) : String
-
-    /**
-     * This destroys an existing loader object and frees it's resources
-     */
-    private external fun destroy(instance : Long)
-
-    /**
-     * This is used to get the [AppEntry] for the specified ROM
-     */
-    fun getAppEntry(uri : Uri) : AppEntry {
-        return if (hasAssets(instance)) {
-            val rawIcon = getIcon(instance)
-            val icon = if (rawIcon.isNotEmpty()) BitmapFactory.decodeByteArray(rawIcon, 0, rawIcon.size) else null
-
-            AppEntry(getApplicationName(instance), getApplicationPublisher(instance), format, uri, icon)
-        } else {
-            AppEntry(context, format, uri)
-        }
-    }
-
-    /**
-     * This checks if the currently loaded ROM is valid
-     */
-    fun valid() : Boolean {
-        return instance != 0L
-    }
-
-    /**
-     * This destroys the C++ loader object
-     */
-    override fun close() {
-        if (valid()) {
-            destroy(instance)
-            instance = 0
-        }
-    }
 }

app/src/main/java/emu/skyline/preference/ActivityResultDelegate.kt

@@ -0,0 +1,17 @@
+/*
+ * SPDX-License-Identifier: MPL-2.0
+ * Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)
+ */
+
+package emu.skyline.preference
+
+import android.content.Intent
+
+/**
+ * Some preferences need results from activities, this delegates the results to them
+ */
+interface ActivityResultDelegate {
+    var requestCode : Int
+
+    fun onActivityResult(requestCode : Int, resultCode : Int, data : Intent?)
+}

app/src/main/java/emu/skyline/preference/ControllerPreference.kt

@@ -14,17 +14,22 @@ import androidx.preference.Preference.SummaryProvider
 import emu.skyline.R
 import emu.skyline.SettingsActivity
 import emu.skyline.input.ControllerActivity
+import emu.skyline.input.InputManager
 
 /**
  * This preference is used to launch [ControllerActivity] using a preference
  */
-class ControllerPreference : Preference {
+class ControllerPreference @JvmOverloads constructor(context : Context?, attrs : AttributeSet? = null, defStyleAttr : Int = R.attr.preferenceStyle) : Preference(context, attrs, defStyleAttr), ActivityResultDelegate {
     /**
      * The index of the controller this preference manages
      */
-    private var index : Int = -1
+    private var index = -1
 
-    constructor(context : Context?, attrs : AttributeSet?, defStyleAttr : Int) : super(context, attrs, defStyleAttr) {
+    private var inputManager : InputManager? = null
+
+    override var requestCode = 0
+
+    init {
         for (i in 0 until attrs!!.attributeCount) {
             val attr = attrs.getAttributeName(i)
 
@@ -42,23 +47,23 @@ class ControllerPreference : Preference {
 
         title = "${context?.getString(R.string.config_controller)} #${index + 1}"
 
-        if (context is SettingsActivity)
+        if (context is SettingsActivity) {
-            summaryProvider = SummaryProvider<ControllerPreference> { _ -> context.inputManager.controllers[index]?.type?.stringRes?.let { context.getString(it) } }
+            inputManager = context.inputManager
+            summaryProvider = SummaryProvider<ControllerPreference> { context.inputManager.controllers[index]?.type?.stringRes?.let { context.getString(it) } }
+        }
     }
 
-    constructor(context : Context?, attrs : AttributeSet?) : this(context, attrs, R.attr.preferenceStyle)
-
-    constructor(context : Context?) : this(context, null)
-
     /**
      * This launches [ControllerActivity] on click to configure the controller
      */
     override fun onClick() {
-        if (context is SettingsActivity)
+        (context as Activity).startActivityForResult(Intent(context, ControllerActivity::class.java).apply { putExtra("index", index) }, requestCode)
-            (context as SettingsActivity).refreshKey = key
+    }
 
-        val intent = Intent(context, ControllerActivity::class.java)
+    override fun onActivityResult(requestCode : Int, resultCode : Int, data : Intent?) {
-        intent.putExtra("index", index)
+        if (this.requestCode == requestCode) {
-        (context as Activity).startActivityForResult(intent, 0)
+            inputManager?.syncObjects()
+            notifyChanged()
+        }
     }
 }

app/src/main/java/emu/skyline/preference/DocumentActivity.kt

@@ -0,0 +1,55 @@
+/*
+ * SPDX-License-Identifier: MPL-2.0
+ * Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)
+ */
+
+package emu.skyline.preference
+
+import android.app.Activity
+import android.content.Intent
+import android.os.Bundle
+import androidx.appcompat.app.AppCompatActivity
+import androidx.preference.PreferenceManager
+
+/**
+ * This activity is used to launch a document picker and saves the result to preferences
+ */
+abstract class DocumentActivity : AppCompatActivity() {
+    companion object {
+        const val KEY_NAME = "key_name"
+    }
+
+    private lateinit var keyName : String
+
+    protected abstract val actionIntent : Intent
+
+    /**
+     * This launches the [Intent.ACTION_OPEN_DOCUMENT_TREE] intent on creation
+     */
+    override fun onCreate(state : Bundle?) {
+        super.onCreate(state)
+
+        keyName = intent.getStringExtra(KEY_NAME)!!
+
+        this.startActivityForResult(actionIntent, 1)
+    }
+
+    /**
+     * This changes the search location preference if the [Intent.ACTION_OPEN_DOCUMENT_TREE] has returned and [finish]es the activity
+     */
+    public override fun onActivityResult(requestCode : Int, resultCode : Int, data : Intent?) {
+        super.onActivityResult(requestCode, resultCode, data)
+
+        if (resultCode == Activity.RESULT_OK && requestCode == 1) {
+            val uri = data!!.data!!
+
+            contentResolver.takePersistableUriPermission(uri, Intent.FLAG_GRANT_READ_URI_PERMISSION)
+
+            PreferenceManager.getDefaultSharedPreferences(this).edit()
+                    .putString(keyName, uri.toString())
+                    .putBoolean("refresh_required", true)
+                    .apply()
+        }
+        finish()
+    }
+}

app/src/main/java/emu/skyline/preference/FileActivity.kt

@@ -0,0 +1,18 @@
+/*
+ * SPDX-License-Identifier: MPL-2.0
+ * Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)
+ */
+
+package emu.skyline.preference
+
+import android.content.Intent
+
+/**
+ * Launches document picker to select one file
+ */
+class FileActivity : DocumentActivity() {
+    override val actionIntent = Intent(Intent.ACTION_OPEN_DOCUMENT).apply {
+        addCategory(Intent.CATEGORY_OPENABLE)
+        type = "*/*"
+    }
+}

app/src/main/java/emu/skyline/preference/FilePreference.kt

@@ -0,0 +1,41 @@
+/*
+ * SPDX-License-Identifier: MPL-2.0
+ * Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)
+ */
+
+package emu.skyline.preference
+
+import android.app.Activity
+import android.content.Context
+import android.content.Intent
+import android.net.Uri
+import android.util.AttributeSet
+import androidx.preference.Preference
+import androidx.preference.PreferenceManager
+import com.google.android.material.snackbar.Snackbar
+import emu.skyline.KeyReader
+import emu.skyline.R
+import emu.skyline.SettingsActivity
+import kotlinx.android.synthetic.main.settings_activity.*
+
+/**
+ * Launches [FileActivity] and process the selected file for key import
+ */
+class FilePreference @JvmOverloads constructor(context : Context?, attrs : AttributeSet? = null, defStyleAttr : Int = androidx.preference.R.attr.preferenceStyle) : Preference(context, attrs, defStyleAttr), ActivityResultDelegate {
+    override var requestCode = 0
+
+    override fun onClick() = (context as Activity).startActivityForResult(Intent(context, FileActivity::class.java).apply { putExtra(DocumentActivity.KEY_NAME, key) }, requestCode)
+
+    override fun onActivityResult(requestCode : Int, resultCode : Int, data : Intent?) {
+        if (this.requestCode == requestCode) {
+            if (key == "prod_keys" || key == "title_keys") {
+                val success = KeyReader.import(
+                        context,
+                        Uri.parse(PreferenceManager.getDefaultSharedPreferences(context).getString(key, "")),
+                        KeyReader.KeyType.parse(key)
+                )
+                Snackbar.make((context as SettingsActivity).settings, if (success) R.string.import_keys_success else R.string.import_keys_failed, Snackbar.LENGTH_LONG).show()
+            }
+        }
+    }
+}

app/src/main/java/emu/skyline/preference/FolderActivity.kt

@@ -5,45 +5,11 @@
 
 package emu.skyline.preference
 
-import android.app.Activity
 import android.content.Intent
-import android.os.Bundle
-import androidx.appcompat.app.AppCompatActivity
-import androidx.preference.PreferenceManager
 
 /**
- * This activity is used to select a new search location and set preferences to reflect that
+ * Launches document picker to select a folder
  */
-class FolderActivity : AppCompatActivity() {
+class FolderActivity : DocumentActivity() {
-    /**
+    override val actionIntent = Intent(Intent.ACTION_OPEN_DOCUMENT_TREE)
-     * This launches the [Intent.ACTION_OPEN_DOCUMENT_TREE] intent on creation
-     */
-    override fun onCreate(state : Bundle?) {
-        super.onCreate(state)
-
-        val intent = Intent(Intent.ACTION_OPEN_DOCUMENT_TREE)
-        this.startActivityForResult(intent, 1)
-    }
-
-    /**
-     * This changes the search location preference if the [Intent.ACTION_OPEN_DOCUMENT_TREE] has returned and [finish]es the activity
-     */
-    public override fun onActivityResult(requestCode : Int, resultCode : Int, data : Intent?) {
-        super.onActivityResult(requestCode, resultCode, data)
-
-        if (resultCode == Activity.RESULT_OK) {
-            if (requestCode == 1) {
-                val uri = data!!.data!!
-
-                contentResolver.takePersistableUriPermission(uri, Intent.FLAG_GRANT_READ_URI_PERMISSION)
-
-                PreferenceManager.getDefaultSharedPreferences(this).edit()
-                        .putString("search_location", uri.toString())
-                        .putBoolean("refresh_required", true)
-                        .apply()
-            }
-        }
-
-        finish()
-    }
 }

app/src/main/java/emu/skyline/preference/FolderPreference.kt

@@ -13,43 +13,27 @@ import android.util.AttributeSet
 import androidx.preference.Preference
 import androidx.preference.Preference.SummaryProvider
 import androidx.preference.R
-import emu.skyline.SettingsActivity
 
 /**
- * This preference shows the decoded URI of it's preference and launches [FolderActivity]
+ * This preference shows the decoded URI of it's preference and launches [DocumentActivity]
  */
-class FolderPreference : Preference {
+class FolderPreference @JvmOverloads constructor(context : Context?, attrs : AttributeSet? = null, defStyleAttr : Int = R.attr.preferenceStyle) : Preference(context, attrs, defStyleAttr), ActivityResultDelegate {
-    /**
+    override var requestCode = 0
-     * The directory the preference is currently set to
-     */
-    private var mDirectory : String? = null
 
-    constructor(context : Context?, attrs : AttributeSet?, defStyleAttr : Int) : super(context, attrs, defStyleAttr) {
+    init {
         summaryProvider = SummaryProvider<FolderPreference> { preference ->
-            preference.onSetInitialValue(null)
+            Uri.decode(preference.getPersistedString(""))
-            Uri.decode(preference.mDirectory) ?: ""
         }
     }
 
-    constructor(context : Context?, attrs : AttributeSet?) : this(context, attrs, R.attr.preferenceStyle)
-
-    constructor(context : Context?) : this(context, null)
-
     /**
-     * This launches [FolderActivity] on click to change the directory
+     * This launches [DocumentActivity] on click to change the directory
      */
     override fun onClick() {
-        if (context is SettingsActivity)
+        (context as Activity).startActivityForResult(Intent(context, FolderActivity::class.java).apply { putExtra(DocumentActivity.KEY_NAME, key) }, requestCode)
-            (context as SettingsActivity).refreshKey = key
-
-        val intent = Intent(context, FolderActivity::class.java)
-        (context as Activity).startActivityForResult(intent, 0)
     }
 
-    /**
+    override fun onActivityResult(requestCode : Int, resultCode : Int, data : Intent?) {
-     * This sets the initial value of [mDirectory]
+        if (requestCode == requestCode) notifyChanged()
-     */
-    override fun onSetInitialValue(defaultValue : Any?) {
-        mDirectory = getPersistedString(defaultValue as String?)
     }
 }

app/src/main/res/layout/app_dialog.xml

@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
         xmlns:app="http://schemas.android.com/apk/res-auto"
+        xmlns:tools="http://schemas.android.com/tools"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_gravity="center_horizontal"
@@ -13,7 +14,8 @@
             android:layout_height="150dp"
             android:contentDescription="@string/icon"
             android:focusable="false"
-            app:shapeAppearanceOverlay="@style/roundedAppImage" />
+            app:shapeAppearanceOverlay="@style/roundedAppImage"
+            tools:src="@drawable/default_icon" />
 
     <LinearLayout
             android:layout_width="wrap_content"
@@ -26,7 +28,8 @@
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:textAppearance="?android:attr/textAppearanceListItem"
-                android:textSize="18sp" />
+                android:textSize="18sp"
+                tools:text="Title" />
 
         <TextView
                 android:id="@+id/game_subtitle"
@@ -34,7 +37,8 @@
                 android:layout_height="wrap_content"
                 android:textAppearance="?android:attr/textAppearanceListItemSecondary"
                 android:textColor="@android:color/tertiary_text_light"
-                android:textSize="14sp" />
+                android:textSize="14sp"
+                tools:text="Subtitle" />
 
         <LinearLayout
                 android:id="@+id/linearLayout"

app/src/main/res/layout/app_item_grid.xml

@@ -51,8 +51,9 @@
                     android:layout_width="match_parent"
                     android:layout_height="wrap_content"
                     android:ellipsize="marquee"
-                    android:fadingEdge="horizontal"
                     android:marqueeRepeatLimit="marquee_forever"
+                    android:paddingStart="15dp"
+                    android:paddingEnd="15dp"
                     android:paddingBottom="15dp"
                     android:singleLine="true"
                     android:textAlignment="center"

app/src/main/res/layout/loader_error_dialog.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.recyclerview.widget.RecyclerView xmlns:android="http://schemas.android.com/apk/res/android"
+        xmlns:app="http://schemas.android.com/apk/res-auto"
+        android:id="@+id/errorRecyclerView"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:clipToPadding="false"
+        android:padding="16dp"
+        app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager" />

app/src/main/res/layout/loader_error_item.xml

@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="utf-8"?>
+<com.google.android.material.card.MaterialCardView xmlns:android="http://schemas.android.com/apk/res/android"
+        xmlns:app="http://schemas.android.com/apk/res-auto"
+        xmlns:tools="http://schemas.android.com/tools"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="vertical"
+        app:cardElevation="0dp"
+        app:cardUseCompatPadding="true"
+        app:strokeColor="?attr/colorOnSurface"
+        app:strokeWidth="1dp">
+
+    <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="vertical"
+            android:padding="16dp">
+
+        <TextView
+                android:id="@+id/errorText"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:textAllCaps="true"
+                android:textColor="#F0FF0000"
+                android:textStyle="bold"
+                tools:text="File" />
+
+        <TextView
+                android:id="@+id/fileText"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="8dp"
+                tools:text="Error" />
+    </LinearLayout>
+</com.google.android.material.card.MaterialCardView>

app/src/main/res/layout/main_activity.xml

@@ -1,5 +1,4 @@
 <?xml version="1.0" encoding="utf-8"?>
-
 <androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
         xmlns:app="http://schemas.android.com/apk/res-auto"
         xmlns:tools="http://schemas.android.com/tools"
@@ -18,6 +17,7 @@
             app:layout_behavior="@string/appbar_scrolling_view_behavior" />
 
     <emu.skyline.views.CustomLinearLayout
+            android:id="@+id/fab_parent"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_gravity="bottom|end"
@@ -30,7 +30,8 @@
                 android:focusable="true"
                 android:orientation="vertical"
                 android:translationX="72dp"
-                android:visibility="gone">
+                android:visibility="gone"
+                tools:visibility="visible">
 
             <com.google.android.material.floatingactionbutton.FloatingActionButton
                     android:id="@+id/refresh_fab"

app/src/main/res/values/strings.xml

@@ -14,6 +14,9 @@
     <string name="pin">Pin</string>
     <string name="play">Play</string>
     <string name="searching_roms">Searching for ROMs</string>
+    <string name="invalid_file">Invalid file</string>
+    <string name="missing_title_key">Missing title key</string>
+    <string name="incomplete_prod_keys">Incomplete production keys</string>
     <!-- Toolbar Logger -->
     <string name="clear">Clear</string>
     <string name="share">Share</string>
@@ -42,6 +45,11 @@
     <string name="docked_enabled">The system will emulate being in docked mode</string>
     <string name="username">Username</string>
     <string name="username_default">@string/app_name</string>
+    <string name="keys">Keys</string>
+    <string name="prod_keys">Production Keys</string>
+    <string name="title_keys">Title Keys</string>
+    <string name="import_keys_success">Successfully imported keys</string>
+    <string name="import_keys_failed">Failed to import keys</string>
     <!-- Input -->
     <string name="input">Input</string>
     <string name="show_osc">Show On-Screen Controls</string>

app/src/main/res/xml/preferences.xml

@@ -51,6 +51,18 @@
                 app:limit="31"
                 app:title="@string/username" />
     </PreferenceCategory>
+    <PreferenceCategory
+            android:key="category_keys"
+            android:title="@string/keys">
+        <emu.skyline.preference.FilePreference
+                app:key="prod_keys"
+                app:title="@string/prod_keys"
+                app:useSimpleSummaryProvider="true" />
+        <emu.skyline.preference.FilePreference
+                app:key="title_keys"
+                app:title="@string/title_keys"
+                app:useSimpleSummaryProvider="true" />
+    </PreferenceCategory>
     <PreferenceCategory
             android:key="category_system"
             android:title="@string/system">

gradle.properties

@@ -19,3 +19,7 @@ org.gradle.daemon=true
 android.useAndroidX=true
 # Automatically convert third-party libraries to use AndroidX
 android.enableJetifier=true
+
+# Enables Prefab
+android.enablePrefab=true
+android.prefabVersion=1.1.0