From a76310b53fbb117e620f2c37350b68dd267f1088 Mon Sep 17 00:00:00 2001
From: Milan Broz <gmazyland@gmail.com>
Date: Mon, 20 Sep 2021 17:42:20 +0200
Subject: [PATCH] Do not try to set compiler optimization flag if wipe is
 implemented in libc.

If zeroing memory is implemented through libc call (like memset_bzero),
compiler should never remove such call. It is not needed to set O0
optimization flag explicitly.

Various checkers like annocheck causes problems with these flags,
just remove it where it makes no sense.

(Moreover, we use the same pattern without compiler magic
in crypt_backend_memzero() already.)
---
 lib/crypto_backend/argon2/core.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/lib/crypto_backend/argon2/core.c b/lib/crypto_backend/argon2/core.c
index b204ba98..db9a7741 100644
--- a/lib/crypto_backend/argon2/core.c
+++ b/lib/crypto_backend/argon2/core.c
@@ -120,18 +120,24 @@ void free_memory(const argon2_context *context, uint8_t *memory,
     }
 }
 
-void NOT_OPTIMIZED secure_wipe_memory(void *v, size_t n) {
 #if defined(_MSC_VER) && VC_GE_2005(_MSC_VER)
+void secure_wipe_memory(void *v, size_t n) {
     SecureZeroMemory(v, n);
+}
 #elif defined memset_s
+void secure_wipe_memory(void *v, size_t n) {
     memset_s(v, n, 0, n);
+}
 #elif defined(HAVE_EXPLICIT_BZERO)
+void secure_wipe_memory(void *v, size_t n) {
     explicit_bzero(v, n);
+}
 #else
+void NOT_OPTIMIZED secure_wipe_memory(void *v, size_t n) {
     static void *(*const volatile memset_sec)(void *, int, size_t) = &memset;
     memset_sec(v, 0, n);
-#endif
 }
+#endif
 
 /* Memory clear flag defaults to true. */
 int FLAG_clear_internal_memory = 1;
-- 
2.27.0