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 * SPDX-License-Identifier: BSD-2-Clause
6 */
7
8 #include <sys/types.h>
9 #include <sys/stat.h>
10 #ifdef HAVE_SYS_RANDOM_H
11 #include <sys/random.h>
12 #endif
13
14 #include <fcntl.h>
15 #ifdef HAVE_UNISTD_H
16 #include <unistd.h>
17 #endif
18
19 #include "fido.h"
20
21 #if defined(_WIN32)
22 #include <windows.h>
23
24 #include <winternl.h>
25 #include <winerror.h>
26 #include <stdio.h>
27 #include <bcrypt.h>
28 #include <sal.h>
29
30 int
fido_get_random(void * buf,size_t len)31 fido_get_random(void *buf, size_t len)
32 {
33 NTSTATUS status;
34
35 status = BCryptGenRandom(NULL, buf, (ULONG)len,
36 BCRYPT_USE_SYSTEM_PREFERRED_RNG);
37
38 if (!NT_SUCCESS(status))
39 return (-1);
40
41 return (0);
42 }
43 #elif defined(HAVE_ARC4RANDOM_BUF)
44 int
fido_get_random(void * buf,size_t len)45 fido_get_random(void *buf, size_t len)
46 {
47 arc4random_buf(buf, len);
48 return (0);
49 }
50 #elif defined(HAVE_GETRANDOM)
51 int
fido_get_random(void * buf,size_t len)52 fido_get_random(void *buf, size_t len)
53 {
54 ssize_t r;
55
56 if ((r = getrandom(buf, len, 0)) < 0 || (size_t)r != len)
57 return (-1);
58
59 return (0);
60 }
61 #elif defined(HAVE_DEV_URANDOM)
62 int
fido_get_random(void * buf,size_t len)63 fido_get_random(void *buf, size_t len)
64 {
65 int fd = -1;
66 int ok = -1;
67 ssize_t r;
68
69 if ((fd = open(FIDO_RANDOM_DEV, O_RDONLY)) < 0)
70 goto fail;
71 if ((r = read(fd, buf, len)) < 0 || (size_t)r != len)
72 goto fail;
73
74 ok = 0;
75 fail:
76 if (fd != -1)
77 close(fd);
78
79 return (ok);
80 }
81 #else
82 #error "please provide an implementation of fido_get_random() for your platform"
83 #endif /* _WIN32 */
84