| /* |
| * 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 "config.h" |
| #include "rtmpdh.h" |
| #include "libavutil/random_seed.h" |
| |
| #define P1024 \ |
| "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1" \ |
| "29024E088A67CC74020BBEA63B139B22514A08798E3404DD" \ |
| "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245" \ |
| "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED" \ |
| "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381" \ |
| "FFFFFFFFFFFFFFFF" |
| |
| #define Q1024 \ |
| "7FFFFFFFFFFFFFFFE487ED5110B4611A62633145C06E0E68" \ |
| "948127044533E63A0105DF531D89CD9128A5043CC71A026E" \ |
| "F7CA8CD9E69D218D98158536F92F8A1BA7F09AB6B6A8E122" \ |
| "F242DABB312F3F637A262174D31BF6B585FFAE5B7A035BF6" \ |
| "F71C35FDAD44CFD2D74F9208BE258FF324943328F67329C0" \ |
| "FFFFFFFFFFFFFFFF" |
| |
| #if CONFIG_GMP || CONFIG_GCRYPT |
| #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_modexp(bn, y, q, p) mpz_powm(bn, y, q, p) |
| #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) |
| #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_modexp(bn, y, q, p) gcry_mpi_powm(bn, y, q, p) |
| #define bn_random(bn, num_bits) gcry_mpi_randomize(bn, num_bits, GCRY_WEAK_RANDOM) |
| #endif |
| |
| #define MAX_BYTES 18000 |
| |
| #define dh_new() av_malloc(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; |
| } |
| |
| bn_modexp(dh->pub_key, dh->g, dh->priv_key, dh->p); |
| |
| 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; |
| |
| bn_new(k); |
| if (!k) |
| return -1; |
| |
| bn_modexp(k, pub_key_bn, dh->priv_key, dh->p); |
| 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); |
| } |
| #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_modexp(bn, y, q, p) \ |
| do { \ |
| 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); \ |
| } while (0) |
| |
| #define dh_new() DH_new() |
| #define dh_generate_key(dh) DH_generate_key(dh) |
| |
| static int dh_compute_key(FF_DH *dh, FFBigNum pub_key_bn, |
| uint32_t secret_key_len, uint8_t *secret_key) |
| { |
| if (secret_key_len < DH_size(dh)) |
| return AVERROR(EINVAL); |
| return DH_compute_key(secret_key, pub_key_bn, dh); |
| } |
| |
| void ff_dh_free(FF_DH *dh) |
| { |
| if (!dh) |
| return; |
| DH_free(dh); |
| } |
| #endif |
| |
| 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 */ |
| bn_modexp(bn, y, q, p); |
| |
| 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; |
| } |
| |
| #ifdef TEST |
| static int test_random_shared_secret(void) |
| { |
| FF_DH *peer1 = NULL, *peer2 = NULL; |
| int ret; |
| uint8_t pubkey1[128], pubkey2[128]; |
| uint8_t sharedkey1[128], sharedkey2[128]; |
| |
| peer1 = ff_dh_init(1024); |
| peer2 = ff_dh_init(1024); |
| if (!peer1 || !peer2) { |
| ret = AVERROR(ENOMEM); |
| goto fail; |
| } |
| if ((ret = ff_dh_generate_public_key(peer1)) < 0) |
| goto fail; |
| if ((ret = ff_dh_generate_public_key(peer2)) < 0) |
| goto fail; |
| if ((ret = ff_dh_write_public_key(peer1, pubkey1, sizeof(pubkey1))) < 0) |
| goto fail; |
| if ((ret = ff_dh_write_public_key(peer2, pubkey2, sizeof(pubkey2))) < 0) |
| goto fail; |
| if ((ret = ff_dh_compute_shared_secret_key(peer1, pubkey2, sizeof(pubkey2), |
| sharedkey1, sizeof(sharedkey1))) < 0) |
| goto fail; |
| if ((ret = ff_dh_compute_shared_secret_key(peer2, pubkey1, sizeof(pubkey1), |
| sharedkey2, sizeof(sharedkey2))) < 0) |
| goto fail; |
| if (memcmp(sharedkey1, sharedkey2, sizeof(sharedkey1))) { |
| printf("Mismatched generated shared key\n"); |
| ret = AVERROR_INVALIDDATA; |
| } else { |
| printf("Generated shared key ok\n"); |
| } |
| fail: |
| ff_dh_free(peer1); |
| ff_dh_free(peer2); |
| return ret; |
| } |
| |
| static const char *private_key = |
| "976C18FCADC255B456564F74F3EEDA59D28AF6B744D743F2357BFD2404797EF896EF1A" |
| "7C1CBEAAA3AB60AF3192D189CFF3F991C9CBBFD78119FCA2181384B94011943B6D6F28" |
| "9E1B708E2D1A0C7771169293F03DA27E561F15F16F0AC9BC858C77A80FA98FD088A232" |
| "19D08BE6F165DE0B02034B18705829FAD0ACB26A5B75EF"; |
| static const char *public_key = |
| "F272ECF8362257C5D2C3CC2229CF9C0A03225BC109B1DBC76A68C394F256ACA3EF5F64" |
| "FC270C26382BF315C19E97A76104A716FC998A651E8610A3AE6CF65D8FAE5D3F32EEA0" |
| "0B32CB9609B494116A825D7142D17B88E3D20EDD98743DE29CF37A23A9F6A58B960591" |
| "3157D5965FCB46DDA73A1F08DD897BAE88DFE6FC937CBA"; |
| static const uint8_t public_key_bin[] = { |
| 0xf2, 0x72, 0xec, 0xf8, 0x36, 0x22, 0x57, 0xc5, 0xd2, 0xc3, 0xcc, 0x22, |
| 0x29, 0xcf, 0x9c, 0x0a, 0x03, 0x22, 0x5b, 0xc1, 0x09, 0xb1, 0xdb, 0xc7, |
| 0x6a, 0x68, 0xc3, 0x94, 0xf2, 0x56, 0xac, 0xa3, 0xef, 0x5f, 0x64, 0xfc, |
| 0x27, 0x0c, 0x26, 0x38, 0x2b, 0xf3, 0x15, 0xc1, 0x9e, 0x97, 0xa7, 0x61, |
| 0x04, 0xa7, 0x16, 0xfc, 0x99, 0x8a, 0x65, 0x1e, 0x86, 0x10, 0xa3, 0xae, |
| 0x6c, 0xf6, 0x5d, 0x8f, 0xae, 0x5d, 0x3f, 0x32, 0xee, 0xa0, 0x0b, 0x32, |
| 0xcb, 0x96, 0x09, 0xb4, 0x94, 0x11, 0x6a, 0x82, 0x5d, 0x71, 0x42, 0xd1, |
| 0x7b, 0x88, 0xe3, 0xd2, 0x0e, 0xdd, 0x98, 0x74, 0x3d, 0xe2, 0x9c, 0xf3, |
| 0x7a, 0x23, 0xa9, 0xf6, 0xa5, 0x8b, 0x96, 0x05, 0x91, 0x31, 0x57, 0xd5, |
| 0x96, 0x5f, 0xcb, 0x46, 0xdd, 0xa7, 0x3a, 0x1f, 0x08, 0xdd, 0x89, 0x7b, |
| 0xae, 0x88, 0xdf, 0xe6, 0xfc, 0x93, 0x7c, 0xba |
| }; |
| static const uint8_t peer_public_key[] = { |
| 0x58, 0x66, 0x05, 0x49, 0x94, 0x23, 0x2b, 0x66, 0x52, 0x13, 0xff, 0x46, |
| 0xf2, 0xb3, 0x79, 0xa9, 0xee, 0xae, 0x1a, 0x13, 0xf0, 0x71, 0x52, 0xfb, |
| 0x93, 0x4e, 0xee, 0x97, 0x05, 0x73, 0x50, 0x7d, 0xaf, 0x02, 0x07, 0x72, |
| 0xac, 0xdc, 0xa3, 0x95, 0x78, 0xee, 0x9a, 0x19, 0x71, 0x7e, 0x99, 0x9f, |
| 0x2a, 0xd4, 0xb3, 0xe2, 0x0c, 0x1d, 0x1a, 0x78, 0x4c, 0xde, 0xf1, 0xad, |
| 0xb4, 0x60, 0xa8, 0x51, 0xac, 0x71, 0xec, 0x86, 0x70, 0xa2, 0x63, 0x36, |
| 0x92, 0x7c, 0xe3, 0x87, 0xee, 0xe4, 0xf1, 0x62, 0x24, 0x74, 0xb4, 0x04, |
| 0xfa, 0x5c, 0xdf, 0xba, 0xfa, 0xa3, 0xc2, 0xbb, 0x62, 0x27, 0xd0, 0xf4, |
| 0xe4, 0x43, 0xda, 0x8a, 0x88, 0x69, 0x60, 0xe2, 0xdb, 0x75, 0x2a, 0x98, |
| 0x9d, 0xb5, 0x50, 0xe3, 0x99, 0xda, 0xe0, 0xa6, 0x14, 0xc9, 0x80, 0x12, |
| 0xf9, 0x3c, 0xac, 0x06, 0x02, 0x7a, 0xde, 0x74 |
| }; |
| static const uint8_t shared_secret[] = { |
| 0xb2, 0xeb, 0xcb, 0x71, 0xf3, 0x61, 0xfb, 0x5b, 0x4e, 0x5c, 0x4c, 0xcf, |
| 0x5c, 0x08, 0x5f, 0x96, 0x26, 0x77, 0x1d, 0x31, 0xf1, 0xe1, 0xf7, 0x4b, |
| 0x92, 0xac, 0x82, 0x2a, 0x88, 0xc7, 0x83, 0xe1, 0xc7, 0xf3, 0xd3, 0x1a, |
| 0x7d, 0xc8, 0x31, 0xe3, 0x97, 0xe4, 0xec, 0x31, 0x0e, 0x8f, 0x73, 0x1a, |
| 0xe4, 0xf6, 0xd8, 0xc8, 0x94, 0xff, 0xa0, 0x03, 0x84, 0x03, 0x0f, 0xa5, |
| 0x30, 0x5d, 0x67, 0xe0, 0x7a, 0x3b, 0x5f, 0xed, 0x4c, 0xf5, 0xbc, 0x18, |
| 0xea, 0xd4, 0x77, 0xa9, 0x07, 0xb3, 0x54, 0x0b, 0x02, 0xd9, 0xc6, 0xb8, |
| 0x66, 0x5e, 0xec, 0xa4, 0xcd, 0x47, 0xed, 0xc9, 0x38, 0xc6, 0x91, 0x08, |
| 0xf3, 0x85, 0x9b, 0x69, 0x16, 0x78, 0x0d, 0xb7, 0x74, 0x51, 0xaa, 0x5b, |
| 0x4d, 0x74, 0xe4, 0x29, 0x2e, 0x9e, 0x8e, 0xf7, 0xe5, 0x42, 0x83, 0xb0, |
| 0x65, 0xb0, 0xce, 0xc6, 0xb2, 0x8f, 0x5b, 0xb0 |
| }; |
| |
| static int test_ref_data(void) |
| { |
| FF_DH *dh; |
| int ret = AVERROR(ENOMEM); |
| uint8_t pubkey_test[128]; |
| uint8_t sharedkey_test[128]; |
| |
| dh = ff_dh_init(1024); |
| if (!dh) |
| goto fail; |
| bn_hex2bn(dh->priv_key, private_key, ret); |
| if (!ret) |
| goto fail; |
| bn_hex2bn(dh->pub_key, public_key, ret); |
| if (!ret) |
| goto fail; |
| if ((ret = ff_dh_write_public_key(dh, pubkey_test, sizeof(pubkey_test))) < 0) |
| goto fail; |
| if (memcmp(pubkey_test, public_key_bin, sizeof(pubkey_test))) { |
| printf("Mismatched generated public key\n"); |
| ret = AVERROR_INVALIDDATA; |
| goto fail; |
| } else { |
| printf("Generated public key ok\n"); |
| } |
| if ((ret = ff_dh_compute_shared_secret_key(dh, peer_public_key, sizeof(peer_public_key), |
| sharedkey_test, sizeof(sharedkey_test))) < 0) |
| goto fail; |
| if (memcmp(shared_secret, sharedkey_test, sizeof(sharedkey_test))) { |
| printf("Mismatched generated shared key\n"); |
| ret = AVERROR_INVALIDDATA; |
| } else { |
| printf("Generated shared key ok\n"); |
| } |
| fail: |
| ff_dh_free(dh); |
| return ret; |
| } |
| |
| int main(void) |
| { |
| if (test_random_shared_secret() < 0) |
| return 1; |
| if (test_ref_data() < 0) |
| return 1; |
| return 0; |
| } |
| #endif |
