random.c revision 1.1.1.1 
1/*
2 * Copyright (c) 2018 Yubico AB. All rights reserved.
3 * Use of this source code is governed by a BSD-style
4 * license that can be found in the LICENSE file.
5 */
6
7#include <sys/types.h>
8#include <sys/stat.h>
9#ifdef HAVE_SYS_RANDOM_H
10#include <sys/random.h>
11#endif
12
13#include <fcntl.h>
14#ifdef HAVE_UNISTD_H
15#include <unistd.h>
16#endif
17
18#include "fido.h"
19
20#if defined(_WIN32)
21#include <windows.h>
22
23#include <winternl.h>
24#include <winerror.h>
25#include <stdio.h>
26#include <bcrypt.h>
27#include <sal.h>
28
29int
30fido_get_random(void *buf, size_t len)
31{
32	NTSTATUS status;
33
34	status = BCryptGenRandom(NULL, buf, (ULONG)len,
35	    BCRYPT_USE_SYSTEM_PREFERRED_RNG);
36
37	if (!NT_SUCCESS(status))
38		return (-1);
39
40	return (0);
41}
42#elif defined(HAVE_ARC4RANDOM_BUF)
43int
44fido_get_random(void *buf, size_t len)
45{
46	arc4random_buf(buf, len);
47	return (0);
48}
49#elif defined(HAVE_GETRANDOM)
50int
51fido_get_random(void *buf, size_t len)
52{
53	ssize_t	r;
54
55	if ((r = getrandom(buf, len, 0)) < 0 || (size_t)r != len)
56		return (-1);
57
58	return (0);
59}
60#elif defined(HAVE_DEV_URANDOM)
61int
62fido_get_random(void *buf, size_t len)
63{
64	int	fd = -1;
65	int	ok = -1;
66	ssize_t	r;
67
68	if ((fd = open(FIDO_RANDOM_DEV, O_RDONLY)) < 0)
69		goto fail;
70	if ((r = read(fd, buf, len)) < 0 || (size_t)r != len)
71		goto fail;
72
73	ok = 0;
74fail:
75	if (fd != -1)
76		close(fd);
77
78	return (ok);
79}
80#else
81#error "please provide an implementation of fido_get_random() for your platform"
82#endif /* _WIN32 */
83