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suricata/src/util-random.c

137 lines
3.3 KiB
C

/* Copyright (C) 2007-2017 Open Information Security Foundation
*
* You can copy, redistribute or modify this Program under the terms of
* the GNU General Public License version 2 as published by the Free
* Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* version 2 along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
/**
* \file
*
* \author Victor Julien <victor@inliniac.net>
*
* Functions for getting a random value based on
* SEI CERT C Coding Standard MSC30-C
*/
#include "suricata-common.h"
#include "util-random.h"
#if !(defined(HAVE_WINCRYPT_H) && defined(OS_WIN32))
#if defined(HAVE_CLOCK_GETTIME)
static long int RandomGetClock(void)
{
struct timespec ts;
clock_gettime(CLOCK_REALTIME, &ts);
// coverity[dont_call : FALSE]
srandom(ts.tv_nsec ^ ts.tv_sec);
long int value = random();
return value;
}
#else
static long int RandomGetPosix(void)
{
struct timeval tv;
memset(&tv, 0, sizeof(tv));
gettimeofday(&tv, NULL);
// coverity[dont_call : FALSE]
srandom(tv.tv_usec ^ tv.tv_sec);
long int value = random();
return value;
}
#endif
#endif /* !(defined(HAVE_WINCRYPT_H) && defined(OS_WIN32)) */
#if defined(HAVE_WINCRYPT_H) && defined(OS_WIN32)
#include <wincrypt.h>
long int RandomGet(void)
{
if (g_disable_randomness)
return 0;
HCRYPTPROV p;
if (!CryptAcquireContext(&p, NULL, NULL, PROV_RSA_FULL, 0)) {
DWORD err = GetLastError();
SCLogDebug("CryptAcquireContext error: %" PRIu32, (uint32_t)err);
if (err == (DWORD)NTE_BAD_KEYSET) {
/* The key doesn't exist yet, create it */
if (!CryptAcquireContext(&p, NULL, NULL, PROV_RSA_FULL,
CRYPT_NEWKEYSET)) {
SCLogDebug("CryptAcquireContext error: %" PRIu32,
(uint32_t)err);
return -1;
}
} else {
return -1;
}
}
long int value = 0;
if (!CryptGenRandom(p, sizeof(value), (BYTE *)&value)) {
(void)CryptReleaseContext(p, 0);
return -1;
}
(void)CryptReleaseContext(p, 0);
return value;
}
#elif defined(HAVE_GETRANDOM)
long int RandomGet(void)
{
if (g_disable_randomness)
return 0;
long int value = 0;
int ret = getrandom(&value, sizeof(value), 0);
/* ret should be sizeof(value), but if it is > 0 and < sizeof(value)
* it's still better than nothing so we return what we have */
if (ret <= 0) {
if (ret == -1 && errno == ENOSYS) {
#if defined(HAVE_CLOCK_GETTIME)
return RandomGetClock();
#else
return RandomGetPosix();
#endif
}
return -1;
}
return value;
}
#elif defined(HAVE_CLOCK_GETTIME)
long int RandomGet(void)
{
if (g_disable_randomness)
return 0;
return RandomGetClock();
}
#else
long int RandomGet(void)
{
if (g_disable_randomness)
return 0;
return RandomGetPosix();
}
#endif