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 "openbsd-compat.h" 9 10 #if !defined(HAVE_EXPLICIT_BZERO) && !defined(_WIN32) 11 12 #include <string.h> 13 14 /* 15 * explicit_bzero - don't let the compiler optimize away bzero 16 */ 17 18 #ifdef HAVE_MEMSET_S 19 20 void 21 explicit_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 */ 34 static void (* volatile ssh_bzero)(void *, size_t) = bzero; 35 36 void 37 explicit_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 /* !defined(HAVE_EXPLICIT_BZERO) && !defined(_WIN32) */ 58