1 files changed, 118 insertions, 0 deletions
diff --git a/src/core/crypto/aes_util.h b/src/core/crypto/aes_util.h
new file mode 100644
index 000000000..9807b9234
--- /dev/null
+++ b/src/core/crypto/aes_util.h
@@ -0,0 +1,118 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "common/assert.h"
+#include "core/file_sys/vfs.h"
+#include "mbedtls/cipher.h"
+
+namespace Crypto {
+
+enum class Mode {
+    CTR = MBEDTLS_CIPHER_AES_128_CTR,
+    ECB = MBEDTLS_CIPHER_AES_128_ECB,
+    XTS = MBEDTLS_CIPHER_AES_128_XTS,
+};
+
+enum class Op {
+    ENCRYPT,
+    DECRYPT,
+};
+
+template <typename Key, size_t KeySize = sizeof(Key)>
+struct AESCipher {
+    static_assert(std::is_same_v<Key, std::array<u8, KeySize>>, "Key must be std::array of u8.");
+    static_assert(KeySize == 0x10 || KeySize == 0x20, "KeySize must be 128 or 256.");
+
+    AESCipher(Key key, Mode mode) {
+        mbedtls_cipher_init(&encryption_context);
+        mbedtls_cipher_init(&decryption_context);
+
+        ASSERT_MSG((mbedtls_cipher_setup(
+                        &encryption_context,
+                        mbedtls_cipher_info_from_type(static_cast<mbedtls_cipher_type_t>(mode))) ||
+                    mbedtls_cipher_setup(&decryption_context,
+                                         mbedtls_cipher_info_from_type(
+                                             static_cast<mbedtls_cipher_type_t>(mode)))) == 0,
+                   "Failed to initialize mbedtls ciphers.");
+
+        ASSERT(
+            !mbedtls_cipher_setkey(&encryption_context, key.data(), KeySize * 8, MBEDTLS_ENCRYPT));
+        ASSERT(
+            !mbedtls_cipher_setkey(&decryption_context, key.data(), KeySize * 8, MBEDTLS_DECRYPT));
+        //"Failed to set key on mbedtls ciphers.");
+    }
+
+    ~AESCipher() {
+        mbedtls_cipher_free(&encryption_context);
+        mbedtls_cipher_free(&decryption_context);
+    }
+
+    void SetIV(std::vector<u8> iv) {
+        ASSERT_MSG((mbedtls_cipher_set_iv(&encryption_context, iv.data(), iv.size()) ||
+                    mbedtls_cipher_set_iv(&decryption_context, iv.data(), iv.size())) == 0,
+                   "Failed to set IV on mbedtls ciphers.");
+    }
+
+    template <typename Source, typename Dest>
+    void Transcode(const Source* src, size_t size, Dest* dest, Op op) {
+        size_t written = 0;
+
+        const auto context = op == Op::ENCRYPT ? &encryption_context : &decryption_context;
+
+        mbedtls_cipher_reset(context);
+
+        if (mbedtls_cipher_get_cipher_mode(context) == MBEDTLS_MODE_XTS) {
+            mbedtls_cipher_update(context, reinterpret_cast<const u8*>(src), size,
+                                  reinterpret_cast<u8*>(dest), &written);
+            if (written != size)
+                LOG_WARNING(Crypto, "Not all data was decrypted requested={:016X}, actual={:016X}.",
+                            size, written);
+        } else {
+            const auto block_size = mbedtls_cipher_get_block_size(context);
+
+            for (size_t offset = 0; offset < size; offset += block_size) {
+                auto length = std::min<size_t>(block_size, size - offset);
+                mbedtls_cipher_update(context, reinterpret_cast<const u8*>(src) + offset, length,
+                                      reinterpret_cast<u8*>(dest) + offset, &written);
+                if (written != length)
+                    LOG_WARNING(Crypto,
+                                "Not all data was decrypted requested={:016X}, actual={:016X}.",
+                                length, written);
+            }
+        }
+
+        mbedtls_cipher_finish(context, nullptr, nullptr);
+    }
+
+    template <typename Source, typename Dest>
+    void XTSTranscode(const Source* src, size_t size, Dest* dest, size_t sector_id,
+                      size_t sector_size, Op op) {
+        if (size % sector_size > 0) {
+            LOG_CRITICAL(Crypto, "Data size must be a multiple of sector size.");
+            return;
+        }
+
+        for (size_t i = 0; i < size; i += sector_size) {
+            SetIV(CalculateNintendoTweak(sector_id++));
+            Transcode<u8, u8>(reinterpret_cast<const u8*>(src) + i, sector_size,
+                              reinterpret_cast<u8*>(dest) + i, op);
+        }
+    }
+
+private:
+    mbedtls_cipher_context_t encryption_context;
+    mbedtls_cipher_context_t decryption_context;
+
+    static std::vector<u8> CalculateNintendoTweak(size_t sector_id) {
+        std::vector<u8> out(0x10);
+        for (size_t i = 0xF; i <= 0xF; --i) {
+            out[i] = sector_id & 0xFF;
+            sector_id >>= 8;
+        }
+        return out;
+    }
+};
+} // namespace Crypto