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bhnd(9): Fix a few mandoc related issues
[FreeBSD/FreeBSD.git] / crypto / openssh / openbsd-compat / explicit_bzero.c
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         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 /* HAVE_EXPLICIT_BZERO */