From 15660bd8570735139d91d0165a2614747f570202 Mon Sep 17 00:00:00 2001
From: Lioncash
Date: Mon, 3 Aug 2020 14:14:39 -0400
Subject: aes_util: Allow SetIV to be non-allocating

In a few places, the data to be set as the IV is already within an array.
We shouldn't require this data to be heap-allocated if it doesn't need
to be. This allows certain callers to reduce heap churn.
---
 src/core/crypto/aes_util.cpp | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

(limited to 'src/core/crypto/aes_util.cpp')

diff --git a/src/core/crypto/aes_util.cpp b/src/core/crypto/aes_util.cpp
index 4be76bb43..330996b24 100644
--- a/src/core/crypto/aes_util.cpp
+++ b/src/core/crypto/aes_util.cpp
@@ -2,6 +2,7 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
+#include <array>
 #include <mbedtls/cipher.h>
 #include "common/assert.h"
 #include "common/logging/log.h"
@@ -10,8 +11,10 @@
 
 namespace Core::Crypto {
 namespace {
-std::vector<u8> CalculateNintendoTweak(std::size_t sector_id) {
-    std::vector<u8> out(0x10);
+using NintendoTweak = std::array<u8, 16>;
+
+NintendoTweak CalculateNintendoTweak(std::size_t sector_id) {
+    NintendoTweak out{};
     for (std::size_t i = 0xF; i <= 0xF; --i) {
         out[i] = sector_id & 0xFF;
         sector_id >>= 8;
@@ -63,13 +66,6 @@ AESCipher<Key, KeySize>::~AESCipher() {
     mbedtls_cipher_free(&ctx->decryption_context);
 }
 
-template <typename Key, std::size_t KeySize>
-void AESCipher<Key, KeySize>::SetIV(std::vector<u8> iv) {
-    ASSERT_MSG((mbedtls_cipher_set_iv(&ctx->encryption_context, iv.data(), iv.size()) ||
-                mbedtls_cipher_set_iv(&ctx->decryption_context, iv.data(), iv.size())) == 0,
-               "Failed to set IV on mbedtls ciphers.");
-}
-
 template <typename Key, std::size_t KeySize>
 void AESCipher<Key, KeySize>::Transcode(const u8* src, std::size_t size, u8* dest, Op op) const {
     auto* const context = op == Op::Encrypt ? &ctx->encryption_context : &ctx->decryption_context;
@@ -124,6 +120,13 @@ void AESCipher<Key, KeySize>::XTSTranscode(const u8* src, std::size_t size, u8*
     }
 }
 
+template <typename Key, std::size_t KeySize>
+void AESCipher<Key, KeySize>::SetIVImpl(const u8* data, std::size_t size) {
+    ASSERT_MSG((mbedtls_cipher_set_iv(&ctx->encryption_context, data, size) ||
+                mbedtls_cipher_set_iv(&ctx->decryption_context, data, size)) == 0,
+               "Failed to set IV on mbedtls ciphers.");
+}
+
 template class AESCipher<Key128>;
 template class AESCipher<Key256>;
 } // namespace Core::Crypto
-- 
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