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/* OPENBSD ORIGINAL: lib/libc/string/explicit_bzero.c */
/* $OpenBSD: explicit_bzero.c,v 1.1 2014/01/22 21:06:45 tedu Exp $ */
/*
* Public domain.
* Written by Ted Unangst
*/
#include "includes.h"
#include <string.h>
/*
* explicit_bzero - don't let the compiler optimize away bzero
*/
#ifndef HAVE_EXPLICIT_BZERO
#ifdef HAVE_EXPLICIT_MEMSET
void
explicit_bzero(void *p, size_t n)
{
(void)explicit_memset(p, 0, n);
}
#elif defined(HAVE_MEMSET_S)
void
explicit_bzero(void *p, size_t n)
{
if (n == 0)
return;
(void)memset_s(p, n, 0, n);
}
#else /* HAVE_MEMSET_S */
/*
* Indirect bzero through a volatile pointer to hopefully avoid
* dead-store optimisation eliminating the call.
*/
static void (* volatile ssh_bzero)(void *, size_t) = bzero;
void
explicit_bzero(void *p, size_t n)
{
if (n == 0)
return;
/*
* clang -fsanitize=memory needs to intercept memset-like functions
* to correctly detect memory initialisation. Make sure one is called
* directly since our indirection trick above successfully confuses it.
*/
#if defined(__has_feature)
# if __has_feature(memory_sanitizer)
memset(p, 0, n);
# endif
#endif
ssh_bzero(p, n);
}
#endif /* HAVE_MEMSET_S */
#endif /* HAVE_EXPLICIT_BZERO */
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