From 2bb619a508ecb3df24be709345fae7ef0dbd434d Mon Sep 17 00:00:00 2001
From: Minty-Meeo <45425365+Minty-Meeo@users.noreply.github.com>
Date: Thu, 23 Mar 2023 10:42:37 -0500
Subject: [PATCH] Resolve [-Wstringop-overflow=]

---
 Source/Core/Common/Crypto/bn.cpp | 27 +++++++++++++++------------
 Source/Core/Common/Crypto/bn.h   | 14 ++++++++------
 2 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/Source/Core/Common/Crypto/bn.cpp b/Source/Core/Common/Crypto/bn.cpp
index 3dc8c75280..28bd216824 100644
--- a/Source/Core/Common/Crypto/bn.cpp
+++ b/Source/Core/Common/Crypto/bn.cpp
@@ -3,42 +3,45 @@
 
 #include "Common/Crypto/bn.h"
 
+#include <cstddef>
 #include <cstdio>
 #include <cstring>
 
 #include "Common/CommonTypes.h"
 
-static void bn_zero(u8* d, int n)
+static void bn_zero(u8* d, const size_t n)
 {
   std::memset(d, 0, n);
 }
 
-static void bn_copy(u8* d, const u8* a, int n)
+static void bn_copy(u8* d, const u8* a, const size_t n)
 {
   std::memcpy(d, a, n);
 }
 
-int bn_compare(const u8* a, const u8* b, int n)
+int bn_compare(const u8* a, const u8* b, const size_t n)
 {
   return std::memcmp(a, b, n);
 }
 
-void bn_sub_modulus(u8* a, const u8* N, int n)
+void bn_sub_modulus(u8* a, const u8* N, const size_t n)
 {
   u8 c = 0;
-  for (int i = n - 1; i >= 0; --i)
+  for (size_t i = n; i > 0;)
   {
+    --i;
     u32 dig = N[i] + c;
     c = (a[i] < dig);
     a[i] -= dig;
   }
 }
 
-void bn_add(u8* d, const u8* a, const u8* b, const u8* N, int n)
+void bn_add(u8* d, const u8* a, const u8* b, const u8* N, const size_t n)
 {
   u8 c = 0;
-  for (int i = n - 1; i >= 0; --i)
+  for (size_t i = n; i > 0;)
   {
+    --i;
     u32 dig = a[i] + b[i] + c;
     c = (dig >= 0x100);
     d[i] = dig;
@@ -51,11 +54,11 @@ void bn_add(u8* d, const u8* a, const u8* b, const u8* N, int n)
     bn_sub_modulus(d, N, n);
 }
 
-void bn_mul(u8* d, const u8* a, const u8* b, const u8* N, int n)
+void bn_mul(u8* d, const u8* a, const u8* b, const u8* N, const size_t n)
 {
   bn_zero(d, n);
 
-  for (int i = 0; i < n; i++)
+  for (size_t i = 0; i < n; i++)
   {
     for (u8 mask = 0x80; mask != 0; mask >>= 1)
     {
@@ -66,13 +69,13 @@ void bn_mul(u8* d, const u8* a, const u8* b, const u8* N, int n)
   }
 }
 
-void bn_exp(u8* d, const u8* a, const u8* N, int n, const u8* e, int en)
+void bn_exp(u8* d, const u8* a, const u8* N, const size_t n, const u8* e, const size_t en)
 {
   u8 t[512];
 
   bn_zero(d, n);
   d[n - 1] = 1;
-  for (int i = 0; i < en; i++)
+  for (size_t i = 0; i < en; i++)
   {
     for (u8 mask = 0x80; mask != 0; mask >>= 1)
     {
@@ -86,7 +89,7 @@ void bn_exp(u8* d, const u8* a, const u8* N, int n, const u8* e, int en)
 }
 
 // only for prime N -- stupid but lazy, see if I care
-void bn_inv(u8* d, const u8* a, const u8* N, int n)
+void bn_inv(u8* d, const u8* a, const u8* N, const size_t n)
 {
   u8 t[512], s[512];
 
diff --git a/Source/Core/Common/Crypto/bn.h b/Source/Core/Common/Crypto/bn.h
index 4070fd5f00..2dcc8c864b 100644
--- a/Source/Core/Common/Crypto/bn.h
+++ b/Source/Core/Common/Crypto/bn.h
@@ -3,13 +3,15 @@
 
 #pragma once
 
+#include <cstddef>
+
 #include "Common/CommonTypes.h"
 
 // bignum arithmetic
 
-int bn_compare(const u8* a, const u8* b, int n);
-void bn_sub_modulus(u8* a, const u8* N, int n);
-void bn_add(u8* d, const u8* a, const u8* b, const u8* N, int n);
-void bn_mul(u8* d, const u8* a, const u8* b, const u8* N, int n);
-void bn_inv(u8* d, const u8* a, const u8* N, int n);  // only for prime N
-void bn_exp(u8* d, const u8* a, const u8* N, int n, const u8* e, int en);
+int bn_compare(const u8* a, const u8* b, size_t n);
+void bn_sub_modulus(u8* a, const u8* N, size_t n);
+void bn_add(u8* d, const u8* a, const u8* b, const u8* N, size_t n);
+void bn_mul(u8* d, const u8* a, const u8* b, const u8* N, size_t n);
+void bn_inv(u8* d, const u8* a, const u8* N, size_t n);  // only for prime N
+void bn_exp(u8* d, const u8* a, const u8* N, size_t n, const u8* e, size_t en);