suricata
util-random.c
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1 /* Copyright (C) 2007-2017 Open Information Security Foundation
2  *
3  * You can copy, redistribute or modify this Program under the terms of
4  * the GNU General Public License version 2 as published by the Free
5  * Software Foundation.
6  *
7  * This program is distributed in the hope that it will be useful,
8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10  * GNU General Public License for more details.
11  *
12  * You should have received a copy of the GNU General Public License
13  * version 2 along with this program; if not, write to the Free Software
14  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
15  * 02110-1301, USA.
16  */
17 
18 /**
19  * \file
20  *
21  * \author Victor Julien <victor@inliniac.net>
22  *
23  * Functions for getting a random value based on
24  * SEI CERT C Coding Standard MSC30-C
25  */
26 
27 #include "suricata-common.h"
28 #include "suricata.h"
29 #include "util-random.h"
30 #include "util-debug.h"
31 
32 #if !(defined(HAVE_WINCRYPT_H) && defined(OS_WIN32))
33 #if defined(HAVE_CLOCK_GETTIME)
34 
35 static long int RandomGetClock(void)
36 {
37  struct timespec ts;
38  clock_gettime(CLOCK_REALTIME, &ts);
39 
40  // coverity[dont_call : FALSE]
41  srandom(ts.tv_nsec ^ ts.tv_sec);
42  long int value = random();
43  return value;
44 }
45 
46 #else
47 
48 static long int RandomGetPosix(void)
49 {
50  struct timeval tv;
51  memset(&tv, 0, sizeof(tv));
52  gettimeofday(&tv, NULL);
53 
54  // coverity[dont_call : FALSE]
55  srandom(tv.tv_usec ^ tv.tv_sec);
56  long int value = random();
57  return value;
58 }
59 
60 #endif
61 #endif /* !(defined(HAVE_WINCRYPT_H) && defined(OS_WIN32)) */
62 
63 #if defined(HAVE_WINCRYPT_H) && defined(OS_WIN32)
64 #include <wincrypt.h>
65 
66 long int RandomGet(void)
67 {
69  return 0;
70 
71  HCRYPTPROV p;
72  if (!CryptAcquireContext(&p, NULL, NULL, PROV_RSA_FULL, 0)) {
73  DWORD err = GetLastError();
74  SCLogDebug("CryptAcquireContext error: %" PRIu32, (uint32_t)err);
75  if (err == (DWORD)NTE_BAD_KEYSET) {
76  /* The key doesn't exist yet, create it */
77  if (!CryptAcquireContext(&p, NULL, NULL, PROV_RSA_FULL,
78  CRYPT_NEWKEYSET)) {
79 
80  SCLogDebug("CryptAcquireContext error: %" PRIu32,
81  (uint32_t)err);
82  return -1;
83  }
84  } else {
85  return -1;
86  }
87  }
88 
89  long int value = 0;
90  if (!CryptGenRandom(p, sizeof(value), (BYTE *)&value)) {
91  (void)CryptReleaseContext(p, 0);
92  return -1;
93  }
94 
95  (void)CryptReleaseContext(p, 0);
96 
97  return value;
98 }
99 #elif defined(HAVE_GETRANDOM)
100 long int RandomGet(void)
101 {
103  return 0;
104 
105  long int value = 0;
106  int ret = getrandom(&value, sizeof(value), 0);
107  /* ret should be sizeof(value), but if it is > 0 and < sizeof(value)
108  * it's still better than nothing so we return what we have */
109  if (ret <= 0) {
110  if (ret == -1 && errno == ENOSYS) {
111 #if defined(HAVE_CLOCK_GETTIME)
112  return RandomGetClock();
113 #else
114  return RandomGetPosix();
115 #endif
116  }
117  return -1;
118  }
119  return value;
120 }
121 #elif defined(HAVE_CLOCK_GETTIME)
122 long int RandomGet(void)
123 {
125  return 0;
126 
127  return RandomGetClock();
128 }
129 #else
130 long int RandomGet(void)
131 {
133  return 0;
134 
135  return RandomGetPosix();
136 }
137 #endif
ts
uint64_t ts
Definition: source-erf-file.c:55
SCLogDebug
#define SCLogDebug(...)
Definition: util-debug.h:296
RandomGet
long int RandomGet(void)
Definition: util-random.c:130
util-debug.h
suricata-common.h
tv
ThreadVars * tv
Definition: fuzz_decodepcapfile.c:32
util-random.h
suricata.h
g_disable_randomness
int g_disable_randomness
Definition: suricata.c:190