diff options
Diffstat (limited to 'openbsd-compat/explicit_bzero.c')
| -rw-r--r-- | openbsd-compat/explicit_bzero.c | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/openbsd-compat/explicit_bzero.c b/openbsd-compat/explicit_bzero.c new file mode 100644 index 0000000..ac64e69 --- /dev/null +++ b/openbsd-compat/explicit_bzero.c @@ -0,0 +1,57 @@ +/* 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 "openbsd-compat.h" + +#if !defined(HAVE_EXPLICIT_BZERO) && !defined(_WIN32) + +#include <string.h> + +/* + * explicit_bzero - don't let the compiler optimize away bzero + */ + +#ifdef 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 /* !defined(HAVE_EXPLICIT_BZERO) && !defined(_WIN32) */ |