1/* 2 * Copyright 2017 Timothy Arceri 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice (including the next 12 * paragraph) shall be included in all copies or substantial portions of the 13 * Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 20 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 21 * SOFTWARE. 22 * 23 */ 24 25#include "detect_os.h" 26 27#if !DETECT_OS_WINDOWS 28#if defined(HAVE_GETRANDOM) 29#include <sys/random.h> 30#endif 31#include <unistd.h> 32#include <fcntl.h> 33#endif 34 35#include <time.h> 36 37#include "rand_xor.h" 38 39/* Super fast random number generator. 40 * 41 * This rand_xorshift128plus function by Sebastiano Vigna belongs 42 * to the public domain. 43 */ 44uint64_t 45rand_xorshift128plus(uint64_t seed[2]) 46{ 47 uint64_t *s = seed; 48 49 uint64_t s1 = s[0]; 50 const uint64_t s0 = s[1]; 51 s[0] = s0; 52 s1 ^= s1 << 23; 53 s[1] = s1 ^ s0 ^ (s1 >> 18) ^ (s0 >> 5); 54 55 return s[1] + s0; 56} 57 58void 59s_rand_xorshift128plus(uint64_t seed[2], bool randomised_seed) 60{ 61 if (!randomised_seed) { 62 /* Use a fixed seed */ 63 seed[0] = 0x3bffb83978e24f88; 64 seed[1] = 0x9238d5d56c71cd35; 65 return; 66 } 67 68#if !DETECT_OS_WINDOWS 69 size_t seed_size = sizeof(uint64_t) * 2; 70 71#if defined(HAVE_GETRANDOM) 72 ssize_t ret = getrandom(seed, seed_size, GRND_NONBLOCK); 73 if (ret == seed_size) 74 return; 75#endif 76 77 int fd = open("/dev/urandom", O_RDONLY); 78 if (fd >= 0) { 79 if (read(fd, seed, seed_size) == seed_size) { 80 close(fd); 81 return; 82 } 83 close(fd); 84 } 85#endif 86 87 seed[0] = 0x3bffb83978e24f88; 88 seed[1] = time(NULL); 89} 90