xref: /freebsd/crypto/openssh/openbsd-compat/explicit_bzero.c (revision 1f4bcc459a76b7aa664f3fd557684cd0ba6da352)
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 /*
11  * explicit_bzero - don't let the compiler optimize away bzero
12  */
13 
14 #ifndef HAVE_EXPLICIT_BZERO
15 
16 #ifdef HAVE_MEMSET_S
17 
18 void
19 explicit_bzero(void *p, size_t n)
20 {
21 	(void)memset_s(p, n, 0, n);
22 }
23 
24 #else /* HAVE_MEMSET_S */
25 
26 /*
27  * Indirect bzero through a volatile pointer to hopefully avoid
28  * dead-store optimisation eliminating the call.
29  */
30 static void (* volatile ssh_bzero)(void *, size_t) = bzero;
31 
32 void
33 explicit_bzero(void *p, size_t n)
34 {
35 	ssh_bzero(p, n);
36 }
37 
38 #endif /* HAVE_MEMSET_S */
39 
40 #endif /* HAVE_EXPLICIT_BZERO */
41