1 /***
2 This file is part of PulseAudio.
3
4 Copyright 2004-2006 Lennart Poettering
5 Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
6
7 PulseAudio is free software; you can redistribute it and/or modify
8 it under the terms of the GNU Lesser General Public License as
9 published by the Free Software Foundation; either version 2.1 of the
10 License, or (at your option) any later version.
11
12 PulseAudio is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
16
17 You should have received a copy of the GNU Lesser General Public
18 License along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
19 ***/
20
21 #ifdef HAVE_CONFIG_H
22 #include <config.h>
23 #endif
24
25 #include <fcntl.h>
26 #include <unistd.h>
27 #include <errno.h>
28 #include <stdlib.h>
29 #include <time.h>
30
31 #ifdef HAVE_WINDOWS_H
32 #include <windows.h>
33 #include <wincrypt.h>
34 #endif
35
36 #include <pulsecore/core-util.h>
37 #include <pulsecore/log.h>
38 #include <pulsecore/macro.h>
39
40 #include "random.h"
41
42 static bool has_whined = false;
43
44 static const char * const devices[] = { "/dev/urandom", "/dev/random", NULL };
45
random_proper(void * ret_data,size_t length)46 static int random_proper(void *ret_data, size_t length) {
47 #ifdef OS_IS_WIN32
48 int ret = -1;
49
50 HCRYPTPROV hCryptProv = 0;
51
52 pa_assert(ret_data);
53 pa_assert(length > 0);
54
55 if (CryptAcquireContext(&hCryptProv, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT | CRYPT_SILENT)) {
56 if (CryptGenRandom(hCryptProv, length, ret_data))
57 ret = 0;
58 CryptReleaseContext(hCryptProv, 0);
59 }
60
61 return ret;
62
63 #else /* OS_IS_WIN32 */
64
65 int fd, ret = -1;
66 ssize_t r = 0;
67 const char *const * device;
68
69 pa_assert(ret_data);
70 pa_assert(length > 0);
71
72 device = devices;
73
74 while (*device) {
75 ret = 0;
76
77 if ((fd = pa_open_cloexec(*device, O_RDONLY, 0)) >= 0) {
78
79 if ((r = pa_loop_read(fd, ret_data, length, NULL)) < 0 || (size_t) r != length)
80 ret = -1;
81
82 pa_close(fd);
83 } else
84 ret = -1;
85
86 if (ret == 0)
87 break;
88
89 device++;
90 }
91
92 return ret;
93 #endif /* OS_IS_WIN32 */
94 }
95
pa_random_seed(void)96 void pa_random_seed(void) {
97 unsigned int seed;
98
99 if (random_proper(&seed, sizeof(unsigned int)) < 0) {
100
101 if (!has_whined) {
102 pa_log_warn("Failed to get proper entropy. Falling back to seeding with current time.");
103 has_whined = true;
104 }
105
106 seed = (unsigned int) time(NULL);
107 }
108
109 srand(seed);
110 }
111
pa_random(void * ret_data,size_t length)112 void pa_random(void *ret_data, size_t length) {
113 uint8_t *p;
114 size_t l;
115
116 pa_assert(ret_data);
117 pa_assert(length > 0);
118
119 if (random_proper(ret_data, length) >= 0)
120 return;
121
122 if (!has_whined) {
123 pa_log_warn("Failed to get proper entropy. Falling back to unsecure pseudo RNG.");
124 has_whined = true;
125 }
126
127 for (p = ret_data, l = length; l > 0; p++, l--)
128 *p = (uint8_t) rand();
129 }
130