/* * Copyright (c) 2009 Baptiste Coudurier <baptiste.coudurier@gmail.com> * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "config.h" #if HAVE_UNISTD_H #include <unistd.h> #endif #if HAVE_IO_H #include <io.h> #endif #if HAVE_BCRYPT #include <windows.h> #include <bcrypt.h> #endif #include <fcntl.h> #include <math.h> #include <time.h> #include <string.h> #include "avassert.h" #include "internal.h" #include "intreadwrite.h" #include "timer.h" #include "random_seed.h" #include "sha.h" #ifndef TEST #define TEST 0 #endif static int read_random(uint32_t *dst, const char *file) { #if HAVE_UNISTD_H int fd = avpriv_open(file, O_RDONLY); int err = -1; if (fd == -1) return -1; err = read(fd, dst, sizeof(*dst)); close(fd); return err; #else return -1; #endif } static uint32_t get_generic_seed(void) { uint64_t tmp[120/8]; struct AVSHA *sha = (void*)tmp; clock_t last_t = 0; clock_t last_td = 0; clock_t init_t = 0; static uint64_t i = 0; static uint32_t buffer[512] = { 0 }; unsigned char digest[20]; uint64_t last_i = i; av_assert0(sizeof(tmp) >= av_sha_size); if(TEST){ memset(buffer, 0, sizeof(buffer)); last_i = i = 0; }else{ #ifdef AV_READ_TIME buffer[13] ^= AV_READ_TIME(); buffer[41] ^= AV_READ_TIME()>>32; #endif } for (;;) { clock_t t = clock(); if (last_t + 2*last_td + (CLOCKS_PER_SEC > 1000) >= t) { last_td = t - last_t; buffer[i & 511] = 1664525*buffer[i & 511] + 1013904223 + (last_td % 3294638521U); } else { last_td = t - last_t; buffer[++i & 511] += last_td % 3294638521U; if ((t - init_t) >= CLOCKS_PER_SEC>>5) if (last_i && i - last_i > 4 || i - last_i > 64 || TEST && i - last_i > 8) break; } last_t = t; if (!init_t) init_t = t; } if(TEST) { buffer[0] = buffer[1] = 0; } else { #ifdef AV_READ_TIME buffer[111] += AV_READ_TIME(); #endif } av_sha_init(sha, 160); av_sha_update(sha, (const uint8_t *)buffer, sizeof(buffer)); av_sha_final(sha, digest); return AV_RB32(digest) + AV_RB32(digest + 16); } uint32_t av_get_random_seed(void) { uint32_t seed; #if HAVE_BCRYPT BCRYPT_ALG_HANDLE algo_handle; NTSTATUS ret = BCryptOpenAlgorithmProvider(&algo_handle, BCRYPT_RNG_ALGORITHM, MS_PRIMITIVE_PROVIDER, 0); if (BCRYPT_SUCCESS(ret)) { NTSTATUS ret = BCryptGenRandom(algo_handle, (UCHAR*)&seed, sizeof(seed), 0); BCryptCloseAlgorithmProvider(algo_handle, 0); if (BCRYPT_SUCCESS(ret)) return seed; } #endif #if HAVE_ARC4RANDOM return arc4random(); #endif if (read_random(&seed, "/dev/urandom") == sizeof(seed)) return seed; if (read_random(&seed, "/dev/random") == sizeof(seed)) return seed; return get_generic_seed(); }