1/* OPENBSD ORIGINAL: lib/libc/string/explicit_bzero.c */ 2/* $OpenBSD: explicit_bzero.c,v 1.1 2014/01/22 21:06:45 tedu Exp $ */ 3/* 4 * Public domain. 5 * Written by Ted Unangst 6 */ 7 8#include "includes.h" 9 10#include <string.h> 11 12/* 13 * explicit_bzero - don't let the compiler optimize away bzero 14 */ 15 16#ifndef HAVE_EXPLICIT_BZERO 17 18#ifdef HAVE_MEMSET_S 19 20void 21explicit_bzero(void *p, size_t n) 22{ 23 if (n == 0) 24 return; 25 (void)memset_s(p, n, 0, n); 26} 27 28#else /* HAVE_MEMSET_S */ 29 30/* 31 * Indirect bzero through a volatile pointer to hopefully avoid 32 * dead-store optimisation eliminating the call. 33 */ 34static void (* volatile ssh_bzero)(void *, size_t) = bzero; 35 36void 37explicit_bzero(void *p, size_t n) 38{ 39 if (n == 0) 40 return; 41 /* 42 * clang -fsanitize=memory needs to intercept memset-like functions 43 * to correctly detect memory initialisation. Make sure one is called 44 * directly since our indirection trick above successfully confuses it. 45 */ 46#if defined(__has_feature) 47# if __has_feature(memory_sanitizer) 48 memset(p, 0, n); 49# endif 50#endif 51 52 ssh_bzero(p, n); 53} 54 55#endif /* HAVE_MEMSET_S */ 56 57#endif /* HAVE_EXPLICIT_BZERO */ 58