/* * 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_CRYPTGENRANDOM #include <windows.h> #include <wincrypt.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) { uint8_t tmp[120]; struct AVSHA *sha = (void*)tmp; clock_t last_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 == t) { buffer[i & 511]++; } else { buffer[++i & 511] += (t - last_t) % 3294638521U; if (last_i && i - last_i > 4 || i - last_i > 64 || TEST && i - last_i > 8) break; } last_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_CRYPTGENRANDOM HCRYPTPROV provider; if (CryptAcquireContext(&provider, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT | CRYPT_SILENT)) { BOOL ret = CryptGenRandom(provider, sizeof(seed), (PBYTE) &seed); CryptReleaseContext(provider, 0); if (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(); } #if TEST #undef printf #define N 256 #include <stdio.h> int main(void) { int i, j, retry; uint32_t seeds[N]; for (retry=0; retry<3; retry++){ for (i=0; i<N; i++){ seeds[i] = av_get_random_seed(); for (j=0; j<i; j++) if (seeds[j] == seeds[i]) goto retry; } printf("seeds OK\n"); return 0; retry:; } printf("FAIL at %d with %X\n", j, seeds[j]); return 1; } #endif