/
githubmirror
/
FFmpeg
Обзор
Документация
Войти
/
githubmirror
/
FFmpeg
Код
Запросы
0
Пакеты
0
Релизы
0
Аналитика
Безопасность
n3.4.14
libavformat/rtmpdh.c
368 строк
11 KB
Clément Bœsch
Merge commit '016387fe0fe3eff1a03ec0673bf4d2967f6cad94'
24 мар 2017, 14:43
24 мар 2017, 14:43
2c47d24
Код
Авторство
О чём код?
/* * RTMP Diffie-Hellmann utilities * Copyright (c) 2009 Andrej Stepanchuk * Copyright (c) 2009-2010 Howard Chu * Copyright (c) 2012 Samuel Pitoiset * * 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 */ /** * @file * RTMP Diffie-Hellmann utilities */ #include <stdint.h> #include <string.h> #include "config.h" #include "libavutil/attributes.h" #include "libavutil/error.h" #include "libavutil/mem.h" #include "libavutil/random_seed.h" #include "rtmpdh.h" #define P1024 \ "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1" \ "29024E088A67CC74020BBEA63B139B22514A08798E3404DD" \ "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245" \ "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED" \ "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381" \ "FFFFFFFFFFFFFFFF" #define Q1024 \ "7FFFFFFFFFFFFFFFE487ED5110B4611A62633145C06E0E68" \ "948127044533E63A0105DF531D89CD9128A5043CC71A026E" \ "F7CA8CD9E69D218D98158536F92F8A1BA7F09AB6B6A8E122" \ "F242DABB312F3F637A262174D31BF6B585FFAE5B7A035BF6" \ "F71C35FDAD44CFD2D74F9208BE258FF324943328F67329C0" \ "FFFFFFFFFFFFFFFF" #if CONFIG_GMP #define bn_new(bn) \ do { \ bn = av_malloc(sizeof(*bn)); \ if (bn) \ mpz_init2(bn, 1); \ } while (0) #define bn_free(bn) \ do { \ mpz_clear(bn); \ av_free(bn); \ } while (0) #define bn_set_word(bn, w) mpz_set_ui(bn, w) #define bn_cmp(a, b) mpz_cmp(a, b) #define bn_copy(to, from) mpz_set(to, from) #define bn_sub_word(bn, w) mpz_sub_ui(bn, bn, w) #define bn_cmp_1(bn) mpz_cmp_ui(bn, 1) #define bn_num_bytes(bn) (mpz_sizeinbase(bn, 2) + 7) / 8 #define bn_bn2bin(bn, buf, len) \ do { \ memset(buf, 0, len); \ if (bn_num_bytes(bn) <= len) \ mpz_export(buf, NULL, 1, 1, 0, 0, bn); \ } while (0) #define bn_bin2bn(bn, buf, len) \ do { \ bn_new(bn); \ if (bn) \ mpz_import(bn, len, 1, 1, 0, 0, buf); \ } while (0) #define bn_hex2bn(bn, buf, ret) \ do { \ bn_new(bn); \ if (bn) \ ret = (mpz_set_str(bn, buf, 16) == 0); \ else \ ret = 1; \ } while (0) #define bn_random(bn, num_bits) \ do { \ int bits = num_bits; \ mpz_set_ui(bn, 0); \ for (bits = num_bits; bits > 0; bits -= 32) { \ mpz_mul_2exp(bn, bn, 32); \ mpz_add_ui(bn, bn, av_get_random_seed()); \ } \ mpz_fdiv_r_2exp(bn, bn, num_bits); \ } while (0) static int bn_modexp(FFBigNum bn, FFBigNum y, FFBigNum q, FFBigNum p) { mpz_powm(bn, y, q, p); return 0; } #elif CONFIG_GCRYPT #define bn_new(bn) \ do { \ if (!gcry_control(GCRYCTL_INITIALIZATION_FINISHED_P)) { \ if (!gcry_check_version("1.5.4")) \ return AVERROR(EINVAL); \ gcry_control(GCRYCTL_DISABLE_SECMEM, 0); \ gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0); \ } \ bn = gcry_mpi_new(1); \ } while (0) #define bn_free(bn) gcry_mpi_release(bn) #define bn_set_word(bn, w) gcry_mpi_set_ui(bn, w) #define bn_cmp(a, b) gcry_mpi_cmp(a, b) #define bn_copy(to, from) gcry_mpi_set(to, from) #define bn_sub_word(bn, w) gcry_mpi_sub_ui(bn, bn, w) #define bn_cmp_1(bn) gcry_mpi_cmp_ui(bn, 1) #define bn_num_bytes(bn) (gcry_mpi_get_nbits(bn) + 7) / 8 #define bn_bn2bin(bn, buf, len) gcry_mpi_print(GCRYMPI_FMT_USG, buf, len, NULL, bn) #define bn_bin2bn(bn, buf, len) gcry_mpi_scan(&bn, GCRYMPI_FMT_USG, buf, len, NULL) #define bn_hex2bn(bn, buf, ret) ret = (gcry_mpi_scan(&bn, GCRYMPI_FMT_HEX, buf, 0, 0) == 0) #define bn_random(bn, num_bits) gcry_mpi_randomize(bn, num_bits, GCRY_WEAK_RANDOM) static int bn_modexp(FFBigNum bn, FFBigNum y, FFBigNum q, FFBigNum p) { gcry_mpi_powm(bn, y, q, p); return 0; } #elif CONFIG_OPENSSL #define bn_new(bn) bn = BN_new() #define bn_free(bn) BN_free(bn) #define bn_set_word(bn, w) BN_set_word(bn, w) #define bn_cmp(a, b) BN_cmp(a, b) #define bn_copy(to, from) BN_copy(to, from) #define bn_sub_word(bn, w) BN_sub_word(bn, w) #define bn_cmp_1(bn) BN_cmp(bn, BN_value_one()) #define bn_num_bytes(bn) BN_num_bytes(bn) #define bn_bn2bin(bn, buf, len) BN_bn2bin(bn, buf) #define bn_bin2bn(bn, buf, len) bn = BN_bin2bn(buf, len, 0) #define bn_hex2bn(bn, buf, ret) ret = BN_hex2bn(&bn, buf) #define bn_random(bn, num_bits) BN_rand(bn, num_bits, 0, 0) static int bn_modexp(FFBigNum bn, FFBigNum y, FFBigNum q, FFBigNum p) { BN_CTX *ctx = BN_CTX_new(); if (!ctx) return AVERROR(ENOMEM); if (!BN_mod_exp(bn, y, q, p, ctx)) { BN_CTX_free(ctx); return AVERROR(EINVAL); } BN_CTX_free(ctx); return 0; } #endif #define MAX_BYTES 18000 #define dh_new() av_mallocz(sizeof(FF_DH)) static FFBigNum dh_generate_key(FF_DH *dh) { int num_bytes; num_bytes = bn_num_bytes(dh->p) - 1; if (num_bytes <= 0 || num_bytes > MAX_BYTES) return NULL; bn_new(dh->priv_key); if (!dh->priv_key) return NULL; bn_random(dh->priv_key, 8 * num_bytes); bn_new(dh->pub_key); if (!dh->pub_key) { bn_free(dh->priv_key); return NULL; } if (bn_modexp(dh->pub_key, dh->g, dh->priv_key, dh->p) < 0) return NULL; return dh->pub_key; } static int dh_compute_key(FF_DH *dh, FFBigNum pub_key_bn, uint32_t secret_key_len, uint8_t *secret_key) { FFBigNum k; int ret; bn_new(k); if (!k) return -1; if ((ret = bn_modexp(k, pub_key_bn, dh->priv_key, dh->p)) < 0) { bn_free(k); return ret; } bn_bn2bin(k, secret_key, secret_key_len); bn_free(k); /* return the length of the shared secret key like DH_compute_key */ return secret_key_len; } void ff_dh_free(FF_DH *dh) { if (!dh) return; bn_free(dh->p); bn_free(dh->g); bn_free(dh->pub_key); bn_free(dh->priv_key); av_free(dh); } static int dh_is_valid_public_key(FFBigNum y, FFBigNum p, FFBigNum q) { FFBigNum bn = NULL; int ret = AVERROR(EINVAL); bn_new(bn); if (!bn) return AVERROR(ENOMEM); /* y must lie in [2, p - 1] */ bn_set_word(bn, 1); if (!bn_cmp(y, bn)) goto fail; /* bn = p - 2 */ bn_copy(bn, p); bn_sub_word(bn, 1); if (!bn_cmp(y, bn)) goto fail; /* Verify with Sophie-Germain prime * * This is a nice test to make sure the public key position is calculated * correctly. This test will fail in about 50% of the cases if applied to * random data. */ /* y must fulfill y^q mod p = 1 */ if ((ret = bn_modexp(bn, y, q, p)) < 0) goto fail; ret = AVERROR(EINVAL); if (bn_cmp_1(bn)) goto fail; ret = 0; fail: bn_free(bn); return ret; } av_cold FF_DH *ff_dh_init(int key_len) { FF_DH *dh; int ret; if (!(dh = dh_new())) return NULL; bn_new(dh->g); if (!dh->g) goto fail; bn_hex2bn(dh->p, P1024, ret); if (!ret) goto fail; bn_set_word(dh->g, 2); dh->length = key_len; return dh; fail: ff_dh_free(dh); return NULL; } int ff_dh_generate_public_key(FF_DH *dh) { int ret = 0; while (!ret) { FFBigNum q1 = NULL; if (!dh_generate_key(dh)) return AVERROR(EINVAL); bn_hex2bn(q1, Q1024, ret); if (!ret) return AVERROR(ENOMEM); ret = dh_is_valid_public_key(dh->pub_key, dh->p, q1); bn_free(q1); if (!ret) { /* the public key is valid */ break; } } return ret; } int ff_dh_write_public_key(FF_DH *dh, uint8_t *pub_key, int pub_key_len) { int len; /* compute the length of the public key */ len = bn_num_bytes(dh->pub_key); if (len <= 0 || len > pub_key_len) return AVERROR(EINVAL); /* convert the public key value into big-endian form */ memset(pub_key, 0, pub_key_len); bn_bn2bin(dh->pub_key, pub_key + pub_key_len - len, len); return 0; } int ff_dh_compute_shared_secret_key(FF_DH *dh, const uint8_t *pub_key, int pub_key_len, uint8_t *secret_key, int secret_key_len) { FFBigNum q1 = NULL, pub_key_bn = NULL; int ret; /* convert the big-endian form of the public key into a bignum */ bn_bin2bn(pub_key_bn, pub_key, pub_key_len); if (!pub_key_bn) return AVERROR(ENOMEM); /* convert the string containing a hexadecimal number into a bignum */ bn_hex2bn(q1, Q1024, ret); if (!ret) { ret = AVERROR(ENOMEM); goto fail; } /* when the public key is valid we have to compute the shared secret key */ if ((ret = dh_is_valid_public_key(pub_key_bn, dh->p, q1)) < 0) { goto fail; } else if ((ret = dh_compute_key(dh, pub_key_bn, secret_key_len, secret_key)) < 0) { ret = AVERROR(EINVAL); goto fail; } fail: bn_free(pub_key_bn); bn_free(q1); return ret; }