From f0c26bafb5b307df520eb5c971eb4ef0475fce06 Mon Sep 17 00:00:00 2001
From: Alex Jbanca <47811206+alexjba@users.noreply.github.com>
Date: Wed, 10 May 2023 12:22:14 +0300
Subject: [PATCH] chore(cherry-pick): Cherry-picking commit 5d5c005: Fix
 burn_stack performance issue

performance(sqlcipher): Fix burn_stack performance issue
---
 burn_stack.c | 23 ++++++++++++++++-------
 zeromem.c    | 10 ++++++----
 2 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/burn_stack.c b/burn_stack.c
index 5d276a4..9cc9826 100644
--- a/burn_stack.c
+++ b/burn_stack.c
@@ -1,6 +1,14 @@
-/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
-/* SPDX-License-Identifier: Unlicense */
-#include "tomcrypt_private.h"
+/* LibTomCrypt, modular cryptographic library -- Tom St Denis
+ *
+ * LibTomCrypt is a library that provides various cryptographic
+ * algorithms in a highly modular and flexible manner.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
+ */
+#include "tomcrypt.h"
 
 /**
    @file burn_stack.c
@@ -13,11 +21,12 @@
 */
 void burn_stack(unsigned long len)
 {
-   unsigned char buf[32];
+   unsigned char buf[len];
    zeromem(buf, sizeof(buf));
-   if (len > (unsigned long)sizeof(buf)) {
-      burn_stack(len - sizeof(buf));
-   }
 }
 
 
+
+/* $Source$ */
+/* $Revision$ */
+/* $Date$ */
diff --git a/zeromem.c b/zeromem.c
index 7d14994..b2ae036 100644
--- a/zeromem.c
+++ b/zeromem.c
@@ -1,6 +1,7 @@
 /* LibTomCrypt, modular cryptographic library -- Tom St Denis */
 /* SPDX-License-Identifier: Unlicense */
 #include "tomcrypt_private.h"
+#include <string.h>
 
 /**
    @file zeromem.c
@@ -14,9 +15,10 @@
 */
 void zeromem(volatile void *out, size_t outlen)
 {
-   volatile char *mem = out;
    LTC_ARGCHKVD(out != NULL);
-   while (outlen-- > 0) {
-      *mem++ = '\0';
-   }
+   memset((void *)out, 0, outlen);
 }
+
+/* $Source$ */
+/* $Revision$ */
+/* $Date$ */