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
29 int
fido_get_random(void * buf,size_t len)30 fido_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)
43 int
fido_get_random(void * buf,size_t len)44 fido_get_random(void *buf, size_t len)
45 {
46 arc4random_buf(buf, len);
47 return (0);
48 }
49 #elif defined(HAVE_GETRANDOM)
50 int
fido_get_random(void * buf,size_t len)51 fido_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)
61 int
fido_get_random(void * buf,size_t len)62 fido_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;
74 fail:
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