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