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 20 void 21 explicit_bzero(void *p, size_t n) 22 { 23 (void)memset_s(p, n, 0, n); 24 } 25 26 #else /* HAVE_MEMSET_S */ 27 28 #if defined(ANDROID) && defined(bzero) 29 /* On some Android versions bzero is a macro */ 30 static void wrapped_bzero(void* dest, size_t sz) { 31 memset(dest, 0, sz); 32 } 33 34 /* 35 * Indirect bzero through a volatile pointer to hopefully avoid 36 * dead-store optimisation eliminating the call. 37 */ 38 static void (* volatile ssh_bzero)(void *, size_t) = wrapped_bzero; 39 #else 40 /* 41 * Indirect bzero through a volatile pointer to hopefully avoid 42 * dead-store optimisation eliminating the call. 43 */ 44 static void (* volatile ssh_bzero)(void *, size_t) = bzero; 45 #endif 46 47 void 48 explicit_bzero(void *p, size_t n) 49 { 50 /* 51 * clang -fsanitize=memory needs to intercept memset-like functions 52 * to correctly detect memory initialisation. Make sure one is called 53 * directly since our indirection trick above sucessfully confuses it. 54 */ 55 #if defined(__has_feature) 56 # if __has_feature(memory_sanitizer) 57 memset(p, 0, n); 58 # endif 59 #endif 60 61 ssh_bzero(p, n); 62 } 63 64 #endif /* HAVE_MEMSET_S */ 65 66 #endif /* HAVE_EXPLICIT_BZERO */ 67
