1 /* 2 * Copyright 2016-2019 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the OpenSSL license (the "License"). You may not use 5 * this file except in compliance with the License. You can obtain a copy 6 * in the file LICENSE in the source distribution or at 7 * https://www.openssl.org/source/license.html 8 */ 9 10 #include <stdlib.h> 11 #include "ssl_locl.h" 12 #include "internal/cryptlib.h" 13 #include <openssl/evp.h> 14 #include <openssl/kdf.h> 15 16 #define TLS13_MAX_LABEL_LEN 249 17 18 /* Always filled with zeros */ 19 static const unsigned char default_zeros[EVP_MAX_MD_SIZE]; 20 21 /* 22 * Given a |secret|; a |label| of length |labellen|; and |data| of length 23 * |datalen| (e.g. typically a hash of the handshake messages), derive a new 24 * secret |outlen| bytes long and store it in the location pointed to be |out|. 25 * The |data| value may be zero length. Any errors will be treated as fatal if 26 * |fatal| is set. Returns 1 on success 0 on failure. 27 */ 28 int tls13_hkdf_expand(SSL *s, const EVP_MD *md, const unsigned char *secret, 29 const unsigned char *label, size_t labellen, 30 const unsigned char *data, size_t datalen, 31 unsigned char *out, size_t outlen, int fatal) 32 { 33 static const unsigned char label_prefix[] = "tls13 "; 34 EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL); 35 int ret; 36 size_t hkdflabellen; 37 size_t hashlen; 38 /* 39 * 2 bytes for length of derived secret + 1 byte for length of combined 40 * prefix and label + bytes for the label itself + 1 byte length of hash 41 * + bytes for the hash itself 42 */ 43 unsigned char hkdflabel[sizeof(uint16_t) + sizeof(uint8_t) + 44 + (sizeof(label_prefix) - 1) + TLS13_MAX_LABEL_LEN 45 + 1 + EVP_MAX_MD_SIZE]; 46 WPACKET pkt; 47 48 if (pctx == NULL) 49 return 0; 50 51 if (labellen > TLS13_MAX_LABEL_LEN) { 52 if (fatal) { 53 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND, 54 ERR_R_INTERNAL_ERROR); 55 } else { 56 /* 57 * Probably we have been called from SSL_export_keying_material(), 58 * or SSL_export_keying_material_early(). 59 */ 60 SSLerr(SSL_F_TLS13_HKDF_EXPAND, SSL_R_TLS_ILLEGAL_EXPORTER_LABEL); 61 } 62 EVP_PKEY_CTX_free(pctx); 63 return 0; 64 } 65 66 hashlen = EVP_MD_size(md); 67 68 if (!WPACKET_init_static_len(&pkt, hkdflabel, sizeof(hkdflabel), 0) 69 || !WPACKET_put_bytes_u16(&pkt, outlen) 70 || !WPACKET_start_sub_packet_u8(&pkt) 71 || !WPACKET_memcpy(&pkt, label_prefix, sizeof(label_prefix) - 1) 72 || !WPACKET_memcpy(&pkt, label, labellen) 73 || !WPACKET_close(&pkt) 74 || !WPACKET_sub_memcpy_u8(&pkt, data, (data == NULL) ? 0 : datalen) 75 || !WPACKET_get_total_written(&pkt, &hkdflabellen) 76 || !WPACKET_finish(&pkt)) { 77 EVP_PKEY_CTX_free(pctx); 78 WPACKET_cleanup(&pkt); 79 if (fatal) 80 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND, 81 ERR_R_INTERNAL_ERROR); 82 else 83 SSLerr(SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR); 84 return 0; 85 } 86 87 ret = EVP_PKEY_derive_init(pctx) <= 0 88 || EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXPAND_ONLY) 89 <= 0 90 || EVP_PKEY_CTX_set_hkdf_md(pctx, md) <= 0 91 || EVP_PKEY_CTX_set1_hkdf_key(pctx, secret, hashlen) <= 0 92 || EVP_PKEY_CTX_add1_hkdf_info(pctx, hkdflabel, hkdflabellen) <= 0 93 || EVP_PKEY_derive(pctx, out, &outlen) <= 0; 94 95 EVP_PKEY_CTX_free(pctx); 96 97 if (ret != 0) { 98 if (fatal) 99 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND, 100 ERR_R_INTERNAL_ERROR); 101 else 102 SSLerr(SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR); 103 } 104 105 return ret == 0; 106 } 107 108 /* 109 * Given a |secret| generate a |key| of length |keylen| bytes. Returns 1 on 110 * success 0 on failure. 111 */ 112 int tls13_derive_key(SSL *s, const EVP_MD *md, const unsigned char *secret, 113 unsigned char *key, size_t keylen) 114 { 115 static const unsigned char keylabel[] = "key"; 116 117 return tls13_hkdf_expand(s, md, secret, keylabel, sizeof(keylabel) - 1, 118 NULL, 0, key, keylen, 1); 119 } 120 121 /* 122 * Given a |secret| generate an |iv| of length |ivlen| bytes. Returns 1 on 123 * success 0 on failure. 124 */ 125 int tls13_derive_iv(SSL *s, const EVP_MD *md, const unsigned char *secret, 126 unsigned char *iv, size_t ivlen) 127 { 128 static const unsigned char ivlabel[] = "iv"; 129 130 return tls13_hkdf_expand(s, md, secret, ivlabel, sizeof(ivlabel) - 1, 131 NULL, 0, iv, ivlen, 1); 132 } 133 134 int tls13_derive_finishedkey(SSL *s, const EVP_MD *md, 135 const unsigned char *secret, 136 unsigned char *fin, size_t finlen) 137 { 138 static const unsigned char finishedlabel[] = "finished"; 139 140 return tls13_hkdf_expand(s, md, secret, finishedlabel, 141 sizeof(finishedlabel) - 1, NULL, 0, fin, finlen, 1); 142 } 143 144 /* 145 * Given the previous secret |prevsecret| and a new input secret |insecret| of 146 * length |insecretlen|, generate a new secret and store it in the location 147 * pointed to by |outsecret|. Returns 1 on success 0 on failure. 148 */ 149 int tls13_generate_secret(SSL *s, const EVP_MD *md, 150 const unsigned char *prevsecret, 151 const unsigned char *insecret, 152 size_t insecretlen, 153 unsigned char *outsecret) 154 { 155 size_t mdlen, prevsecretlen; 156 int mdleni; 157 int ret; 158 EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL); 159 static const char derived_secret_label[] = "derived"; 160 unsigned char preextractsec[EVP_MAX_MD_SIZE]; 161 162 if (pctx == NULL) { 163 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET, 164 ERR_R_INTERNAL_ERROR); 165 return 0; 166 } 167 168 mdleni = EVP_MD_size(md); 169 /* Ensure cast to size_t is safe */ 170 if (!ossl_assert(mdleni >= 0)) { 171 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET, 172 ERR_R_INTERNAL_ERROR); 173 return 0; 174 } 175 mdlen = (size_t)mdleni; 176 177 if (insecret == NULL) { 178 insecret = default_zeros; 179 insecretlen = mdlen; 180 } 181 if (prevsecret == NULL) { 182 prevsecret = default_zeros; 183 prevsecretlen = 0; 184 } else { 185 EVP_MD_CTX *mctx = EVP_MD_CTX_new(); 186 unsigned char hash[EVP_MAX_MD_SIZE]; 187 188 /* The pre-extract derive step uses a hash of no messages */ 189 if (mctx == NULL 190 || EVP_DigestInit_ex(mctx, md, NULL) <= 0 191 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) { 192 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET, 193 ERR_R_INTERNAL_ERROR); 194 EVP_MD_CTX_free(mctx); 195 EVP_PKEY_CTX_free(pctx); 196 return 0; 197 } 198 EVP_MD_CTX_free(mctx); 199 200 /* Generate the pre-extract secret */ 201 if (!tls13_hkdf_expand(s, md, prevsecret, 202 (unsigned char *)derived_secret_label, 203 sizeof(derived_secret_label) - 1, hash, mdlen, 204 preextractsec, mdlen, 1)) { 205 /* SSLfatal() already called */ 206 EVP_PKEY_CTX_free(pctx); 207 return 0; 208 } 209 210 prevsecret = preextractsec; 211 prevsecretlen = mdlen; 212 } 213 214 ret = EVP_PKEY_derive_init(pctx) <= 0 215 || EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY) 216 <= 0 217 || EVP_PKEY_CTX_set_hkdf_md(pctx, md) <= 0 218 || EVP_PKEY_CTX_set1_hkdf_key(pctx, insecret, insecretlen) <= 0 219 || EVP_PKEY_CTX_set1_hkdf_salt(pctx, prevsecret, prevsecretlen) 220 <= 0 221 || EVP_PKEY_derive(pctx, outsecret, &mdlen) 222 <= 0; 223 224 if (ret != 0) 225 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET, 226 ERR_R_INTERNAL_ERROR); 227 228 EVP_PKEY_CTX_free(pctx); 229 if (prevsecret == preextractsec) 230 OPENSSL_cleanse(preextractsec, mdlen); 231 return ret == 0; 232 } 233 234 /* 235 * Given an input secret |insecret| of length |insecretlen| generate the 236 * handshake secret. This requires the early secret to already have been 237 * generated. Returns 1 on success 0 on failure. 238 */ 239 int tls13_generate_handshake_secret(SSL *s, const unsigned char *insecret, 240 size_t insecretlen) 241 { 242 /* Calls SSLfatal() if required */ 243 return tls13_generate_secret(s, ssl_handshake_md(s), s->early_secret, 244 insecret, insecretlen, 245 (unsigned char *)&s->handshake_secret); 246 } 247 248 /* 249 * Given the handshake secret |prev| of length |prevlen| generate the master 250 * secret and store its length in |*secret_size|. Returns 1 on success 0 on 251 * failure. 252 */ 253 int tls13_generate_master_secret(SSL *s, unsigned char *out, 254 unsigned char *prev, size_t prevlen, 255 size_t *secret_size) 256 { 257 const EVP_MD *md = ssl_handshake_md(s); 258 259 *secret_size = EVP_MD_size(md); 260 /* Calls SSLfatal() if required */ 261 return tls13_generate_secret(s, md, prev, NULL, 0, out); 262 } 263 264 /* 265 * Generates the mac for the Finished message. Returns the length of the MAC or 266 * 0 on error. 267 */ 268 size_t tls13_final_finish_mac(SSL *s, const char *str, size_t slen, 269 unsigned char *out) 270 { 271 const EVP_MD *md = ssl_handshake_md(s); 272 unsigned char hash[EVP_MAX_MD_SIZE]; 273 size_t hashlen, ret = 0; 274 EVP_PKEY *key = NULL; 275 EVP_MD_CTX *ctx = EVP_MD_CTX_new(); 276 277 if (!ssl_handshake_hash(s, hash, sizeof(hash), &hashlen)) { 278 /* SSLfatal() already called */ 279 goto err; 280 } 281 282 if (str == s->method->ssl3_enc->server_finished_label) { 283 key = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL, 284 s->server_finished_secret, hashlen); 285 } else if (SSL_IS_FIRST_HANDSHAKE(s)) { 286 key = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL, 287 s->client_finished_secret, hashlen); 288 } else { 289 unsigned char finsecret[EVP_MAX_MD_SIZE]; 290 291 if (!tls13_derive_finishedkey(s, ssl_handshake_md(s), 292 s->client_app_traffic_secret, 293 finsecret, hashlen)) 294 goto err; 295 296 key = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL, finsecret, 297 hashlen); 298 OPENSSL_cleanse(finsecret, sizeof(finsecret)); 299 } 300 301 if (key == NULL 302 || ctx == NULL 303 || EVP_DigestSignInit(ctx, NULL, md, NULL, key) <= 0 304 || EVP_DigestSignUpdate(ctx, hash, hashlen) <= 0 305 || EVP_DigestSignFinal(ctx, out, &hashlen) <= 0) { 306 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_FINAL_FINISH_MAC, 307 ERR_R_INTERNAL_ERROR); 308 goto err; 309 } 310 311 ret = hashlen; 312 err: 313 EVP_PKEY_free(key); 314 EVP_MD_CTX_free(ctx); 315 return ret; 316 } 317 318 /* 319 * There isn't really a key block in TLSv1.3, but we still need this function 320 * for initialising the cipher and hash. Returns 1 on success or 0 on failure. 321 */ 322 int tls13_setup_key_block(SSL *s) 323 { 324 const EVP_CIPHER *c; 325 const EVP_MD *hash; 326 327 s->session->cipher = s->s3->tmp.new_cipher; 328 if (!ssl_cipher_get_evp(s->session, &c, &hash, NULL, NULL, NULL, 0)) { 329 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_SETUP_KEY_BLOCK, 330 SSL_R_CIPHER_OR_HASH_UNAVAILABLE); 331 return 0; 332 } 333 334 s->s3->tmp.new_sym_enc = c; 335 s->s3->tmp.new_hash = hash; 336 337 return 1; 338 } 339 340 static int derive_secret_key_and_iv(SSL *s, int sending, const EVP_MD *md, 341 const EVP_CIPHER *ciph, 342 const unsigned char *insecret, 343 const unsigned char *hash, 344 const unsigned char *label, 345 size_t labellen, unsigned char *secret, 346 unsigned char *iv, EVP_CIPHER_CTX *ciph_ctx) 347 { 348 unsigned char key[EVP_MAX_KEY_LENGTH]; 349 size_t ivlen, keylen, taglen; 350 int hashleni = EVP_MD_size(md); 351 size_t hashlen; 352 353 /* Ensure cast to size_t is safe */ 354 if (!ossl_assert(hashleni >= 0)) { 355 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DERIVE_SECRET_KEY_AND_IV, 356 ERR_R_EVP_LIB); 357 goto err; 358 } 359 hashlen = (size_t)hashleni; 360 361 if (!tls13_hkdf_expand(s, md, insecret, label, labellen, hash, hashlen, 362 secret, hashlen, 1)) { 363 /* SSLfatal() already called */ 364 goto err; 365 } 366 367 /* TODO(size_t): convert me */ 368 keylen = EVP_CIPHER_key_length(ciph); 369 if (EVP_CIPHER_mode(ciph) == EVP_CIPH_CCM_MODE) { 370 uint32_t algenc; 371 372 ivlen = EVP_CCM_TLS_IV_LEN; 373 if (s->s3->tmp.new_cipher == NULL) { 374 /* We've not selected a cipher yet - we must be doing early data */ 375 algenc = s->session->cipher->algorithm_enc; 376 } else { 377 algenc = s->s3->tmp.new_cipher->algorithm_enc; 378 } 379 if (algenc & (SSL_AES128CCM8 | SSL_AES256CCM8)) 380 taglen = EVP_CCM8_TLS_TAG_LEN; 381 else 382 taglen = EVP_CCM_TLS_TAG_LEN; 383 } else { 384 ivlen = EVP_CIPHER_iv_length(ciph); 385 taglen = 0; 386 } 387 388 if (!tls13_derive_key(s, md, secret, key, keylen) 389 || !tls13_derive_iv(s, md, secret, iv, ivlen)) { 390 /* SSLfatal() already called */ 391 goto err; 392 } 393 394 if (EVP_CipherInit_ex(ciph_ctx, ciph, NULL, NULL, NULL, sending) <= 0 395 || !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL) 396 || (taglen != 0 && !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_TAG, 397 taglen, NULL)) 398 || EVP_CipherInit_ex(ciph_ctx, NULL, NULL, key, NULL, -1) <= 0) { 399 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DERIVE_SECRET_KEY_AND_IV, 400 ERR_R_EVP_LIB); 401 goto err; 402 } 403 404 return 1; 405 err: 406 OPENSSL_cleanse(key, sizeof(key)); 407 return 0; 408 } 409 410 int tls13_change_cipher_state(SSL *s, int which) 411 { 412 static const unsigned char client_early_traffic[] = "c e traffic"; 413 static const unsigned char client_handshake_traffic[] = "c hs traffic"; 414 static const unsigned char client_application_traffic[] = "c ap traffic"; 415 static const unsigned char server_handshake_traffic[] = "s hs traffic"; 416 static const unsigned char server_application_traffic[] = "s ap traffic"; 417 static const unsigned char exporter_master_secret[] = "exp master"; 418 static const unsigned char resumption_master_secret[] = "res master"; 419 static const unsigned char early_exporter_master_secret[] = "e exp master"; 420 unsigned char *iv; 421 unsigned char secret[EVP_MAX_MD_SIZE]; 422 unsigned char hashval[EVP_MAX_MD_SIZE]; 423 unsigned char *hash = hashval; 424 unsigned char *insecret; 425 unsigned char *finsecret = NULL; 426 const char *log_label = NULL; 427 EVP_CIPHER_CTX *ciph_ctx; 428 size_t finsecretlen = 0; 429 const unsigned char *label; 430 size_t labellen, hashlen = 0; 431 int ret = 0; 432 const EVP_MD *md = NULL; 433 const EVP_CIPHER *cipher = NULL; 434 435 if (which & SSL3_CC_READ) { 436 if (s->enc_read_ctx != NULL) { 437 EVP_CIPHER_CTX_reset(s->enc_read_ctx); 438 } else { 439 s->enc_read_ctx = EVP_CIPHER_CTX_new(); 440 if (s->enc_read_ctx == NULL) { 441 SSLfatal(s, SSL_AD_INTERNAL_ERROR, 442 SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE); 443 goto err; 444 } 445 } 446 ciph_ctx = s->enc_read_ctx; 447 iv = s->read_iv; 448 449 RECORD_LAYER_reset_read_sequence(&s->rlayer); 450 } else { 451 s->statem.enc_write_state = ENC_WRITE_STATE_INVALID; 452 if (s->enc_write_ctx != NULL) { 453 EVP_CIPHER_CTX_reset(s->enc_write_ctx); 454 } else { 455 s->enc_write_ctx = EVP_CIPHER_CTX_new(); 456 if (s->enc_write_ctx == NULL) { 457 SSLfatal(s, SSL_AD_INTERNAL_ERROR, 458 SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE); 459 goto err; 460 } 461 } 462 ciph_ctx = s->enc_write_ctx; 463 iv = s->write_iv; 464 465 RECORD_LAYER_reset_write_sequence(&s->rlayer); 466 } 467 468 if (((which & SSL3_CC_CLIENT) && (which & SSL3_CC_WRITE)) 469 || ((which & SSL3_CC_SERVER) && (which & SSL3_CC_READ))) { 470 if (which & SSL3_CC_EARLY) { 471 EVP_MD_CTX *mdctx = NULL; 472 long handlen; 473 void *hdata; 474 unsigned int hashlenui; 475 const SSL_CIPHER *sslcipher = SSL_SESSION_get0_cipher(s->session); 476 477 insecret = s->early_secret; 478 label = client_early_traffic; 479 labellen = sizeof(client_early_traffic) - 1; 480 log_label = CLIENT_EARLY_LABEL; 481 482 handlen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata); 483 if (handlen <= 0) { 484 SSLfatal(s, SSL_AD_INTERNAL_ERROR, 485 SSL_F_TLS13_CHANGE_CIPHER_STATE, 486 SSL_R_BAD_HANDSHAKE_LENGTH); 487 goto err; 488 } 489 490 if (s->early_data_state == SSL_EARLY_DATA_CONNECTING 491 && s->max_early_data > 0 492 && s->session->ext.max_early_data == 0) { 493 /* 494 * If we are attempting to send early data, and we've decided to 495 * actually do it but max_early_data in s->session is 0 then we 496 * must be using an external PSK. 497 */ 498 if (!ossl_assert(s->psksession != NULL 499 && s->max_early_data == 500 s->psksession->ext.max_early_data)) { 501 SSLfatal(s, SSL_AD_INTERNAL_ERROR, 502 SSL_F_TLS13_CHANGE_CIPHER_STATE, 503 ERR_R_INTERNAL_ERROR); 504 goto err; 505 } 506 sslcipher = SSL_SESSION_get0_cipher(s->psksession); 507 } 508 if (sslcipher == NULL) { 509 SSLfatal(s, SSL_AD_INTERNAL_ERROR, 510 SSL_F_TLS13_CHANGE_CIPHER_STATE, SSL_R_BAD_PSK); 511 goto err; 512 } 513 514 /* 515 * We need to calculate the handshake digest using the digest from 516 * the session. We haven't yet selected our ciphersuite so we can't 517 * use ssl_handshake_md(). 518 */ 519 mdctx = EVP_MD_CTX_new(); 520 if (mdctx == NULL) { 521 SSLfatal(s, SSL_AD_INTERNAL_ERROR, 522 SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE); 523 goto err; 524 } 525 cipher = EVP_get_cipherbynid(SSL_CIPHER_get_cipher_nid(sslcipher)); 526 md = ssl_md(sslcipher->algorithm2); 527 if (md == NULL || !EVP_DigestInit_ex(mdctx, md, NULL) 528 || !EVP_DigestUpdate(mdctx, hdata, handlen) 529 || !EVP_DigestFinal_ex(mdctx, hashval, &hashlenui)) { 530 SSLfatal(s, SSL_AD_INTERNAL_ERROR, 531 SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR); 532 EVP_MD_CTX_free(mdctx); 533 goto err; 534 } 535 hashlen = hashlenui; 536 EVP_MD_CTX_free(mdctx); 537 538 if (!tls13_hkdf_expand(s, md, insecret, 539 early_exporter_master_secret, 540 sizeof(early_exporter_master_secret) - 1, 541 hashval, hashlen, 542 s->early_exporter_master_secret, hashlen, 543 1)) { 544 SSLfatal(s, SSL_AD_INTERNAL_ERROR, 545 SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR); 546 goto err; 547 } 548 549 if (!ssl_log_secret(s, EARLY_EXPORTER_SECRET_LABEL, 550 s->early_exporter_master_secret, hashlen)) { 551 /* SSLfatal() already called */ 552 goto err; 553 } 554 } else if (which & SSL3_CC_HANDSHAKE) { 555 insecret = s->handshake_secret; 556 finsecret = s->client_finished_secret; 557 finsecretlen = EVP_MD_size(ssl_handshake_md(s)); 558 label = client_handshake_traffic; 559 labellen = sizeof(client_handshake_traffic) - 1; 560 log_label = CLIENT_HANDSHAKE_LABEL; 561 /* 562 * The handshake hash used for the server read/client write handshake 563 * traffic secret is the same as the hash for the server 564 * write/client read handshake traffic secret. However, if we 565 * processed early data then we delay changing the server 566 * read/client write cipher state until later, and the handshake 567 * hashes have moved on. Therefore we use the value saved earlier 568 * when we did the server write/client read change cipher state. 569 */ 570 hash = s->handshake_traffic_hash; 571 } else { 572 insecret = s->master_secret; 573 label = client_application_traffic; 574 labellen = sizeof(client_application_traffic) - 1; 575 log_label = CLIENT_APPLICATION_LABEL; 576 /* 577 * For this we only use the handshake hashes up until the server 578 * Finished hash. We do not include the client's Finished, which is 579 * what ssl_handshake_hash() would give us. Instead we use the 580 * previously saved value. 581 */ 582 hash = s->server_finished_hash; 583 } 584 } else { 585 /* Early data never applies to client-read/server-write */ 586 if (which & SSL3_CC_HANDSHAKE) { 587 insecret = s->handshake_secret; 588 finsecret = s->server_finished_secret; 589 finsecretlen = EVP_MD_size(ssl_handshake_md(s)); 590 label = server_handshake_traffic; 591 labellen = sizeof(server_handshake_traffic) - 1; 592 log_label = SERVER_HANDSHAKE_LABEL; 593 } else { 594 insecret = s->master_secret; 595 label = server_application_traffic; 596 labellen = sizeof(server_application_traffic) - 1; 597 log_label = SERVER_APPLICATION_LABEL; 598 } 599 } 600 601 if (!(which & SSL3_CC_EARLY)) { 602 md = ssl_handshake_md(s); 603 cipher = s->s3->tmp.new_sym_enc; 604 if (!ssl3_digest_cached_records(s, 1) 605 || !ssl_handshake_hash(s, hashval, sizeof(hashval), &hashlen)) { 606 /* SSLfatal() already called */; 607 goto err; 608 } 609 } 610 611 /* 612 * Save the hash of handshakes up to now for use when we calculate the 613 * client application traffic secret 614 */ 615 if (label == server_application_traffic) 616 memcpy(s->server_finished_hash, hashval, hashlen); 617 618 if (label == server_handshake_traffic) 619 memcpy(s->handshake_traffic_hash, hashval, hashlen); 620 621 if (label == client_application_traffic) { 622 /* 623 * We also create the resumption master secret, but this time use the 624 * hash for the whole handshake including the Client Finished 625 */ 626 if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret, 627 resumption_master_secret, 628 sizeof(resumption_master_secret) - 1, 629 hashval, hashlen, s->resumption_master_secret, 630 hashlen, 1)) { 631 /* SSLfatal() already called */ 632 goto err; 633 } 634 } 635 636 if (!derive_secret_key_and_iv(s, which & SSL3_CC_WRITE, md, cipher, 637 insecret, hash, label, labellen, secret, iv, 638 ciph_ctx)) { 639 /* SSLfatal() already called */ 640 goto err; 641 } 642 643 if (label == server_application_traffic) { 644 memcpy(s->server_app_traffic_secret, secret, hashlen); 645 /* Now we create the exporter master secret */ 646 if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret, 647 exporter_master_secret, 648 sizeof(exporter_master_secret) - 1, 649 hash, hashlen, s->exporter_master_secret, 650 hashlen, 1)) { 651 /* SSLfatal() already called */ 652 goto err; 653 } 654 655 if (!ssl_log_secret(s, EXPORTER_SECRET_LABEL, s->exporter_master_secret, 656 hashlen)) { 657 /* SSLfatal() already called */ 658 goto err; 659 } 660 } else if (label == client_application_traffic) 661 memcpy(s->client_app_traffic_secret, secret, hashlen); 662 663 if (!ssl_log_secret(s, log_label, secret, hashlen)) { 664 /* SSLfatal() already called */ 665 goto err; 666 } 667 668 if (finsecret != NULL 669 && !tls13_derive_finishedkey(s, ssl_handshake_md(s), secret, 670 finsecret, finsecretlen)) { 671 /* SSLfatal() already called */ 672 goto err; 673 } 674 675 if (!s->server && label == client_early_traffic) 676 s->statem.enc_write_state = ENC_WRITE_STATE_WRITE_PLAIN_ALERTS; 677 else 678 s->statem.enc_write_state = ENC_WRITE_STATE_VALID; 679 ret = 1; 680 err: 681 OPENSSL_cleanse(secret, sizeof(secret)); 682 return ret; 683 } 684 685 int tls13_update_key(SSL *s, int sending) 686 { 687 static const unsigned char application_traffic[] = "traffic upd"; 688 const EVP_MD *md = ssl_handshake_md(s); 689 size_t hashlen = EVP_MD_size(md); 690 unsigned char *insecret, *iv; 691 unsigned char secret[EVP_MAX_MD_SIZE]; 692 EVP_CIPHER_CTX *ciph_ctx; 693 int ret = 0; 694 695 if (s->server == sending) 696 insecret = s->server_app_traffic_secret; 697 else 698 insecret = s->client_app_traffic_secret; 699 700 if (sending) { 701 s->statem.enc_write_state = ENC_WRITE_STATE_INVALID; 702 iv = s->write_iv; 703 ciph_ctx = s->enc_write_ctx; 704 RECORD_LAYER_reset_write_sequence(&s->rlayer); 705 } else { 706 iv = s->read_iv; 707 ciph_ctx = s->enc_read_ctx; 708 RECORD_LAYER_reset_read_sequence(&s->rlayer); 709 } 710 711 if (!derive_secret_key_and_iv(s, sending, ssl_handshake_md(s), 712 s->s3->tmp.new_sym_enc, insecret, NULL, 713 application_traffic, 714 sizeof(application_traffic) - 1, secret, iv, 715 ciph_ctx)) { 716 /* SSLfatal() already called */ 717 goto err; 718 } 719 720 memcpy(insecret, secret, hashlen); 721 722 s->statem.enc_write_state = ENC_WRITE_STATE_VALID; 723 ret = 1; 724 err: 725 OPENSSL_cleanse(secret, sizeof(secret)); 726 return ret; 727 } 728 729 int tls13_alert_code(int code) 730 { 731 /* There are 2 additional alerts in TLSv1.3 compared to TLSv1.2 */ 732 if (code == SSL_AD_MISSING_EXTENSION || code == SSL_AD_CERTIFICATE_REQUIRED) 733 return code; 734 735 return tls1_alert_code(code); 736 } 737 738 int tls13_export_keying_material(SSL *s, unsigned char *out, size_t olen, 739 const char *label, size_t llen, 740 const unsigned char *context, 741 size_t contextlen, int use_context) 742 { 743 unsigned char exportsecret[EVP_MAX_MD_SIZE]; 744 static const unsigned char exporterlabel[] = "exporter"; 745 unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE]; 746 const EVP_MD *md = ssl_handshake_md(s); 747 EVP_MD_CTX *ctx = EVP_MD_CTX_new(); 748 unsigned int hashsize, datalen; 749 int ret = 0; 750 751 if (ctx == NULL || !ossl_statem_export_allowed(s)) 752 goto err; 753 754 if (!use_context) 755 contextlen = 0; 756 757 if (EVP_DigestInit_ex(ctx, md, NULL) <= 0 758 || EVP_DigestUpdate(ctx, context, contextlen) <= 0 759 || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0 760 || EVP_DigestInit_ex(ctx, md, NULL) <= 0 761 || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0 762 || !tls13_hkdf_expand(s, md, s->exporter_master_secret, 763 (const unsigned char *)label, llen, 764 data, datalen, exportsecret, hashsize, 0) 765 || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel, 766 sizeof(exporterlabel) - 1, hash, hashsize, 767 out, olen, 0)) 768 goto err; 769 770 ret = 1; 771 err: 772 EVP_MD_CTX_free(ctx); 773 return ret; 774 } 775 776 int tls13_export_keying_material_early(SSL *s, unsigned char *out, size_t olen, 777 const char *label, size_t llen, 778 const unsigned char *context, 779 size_t contextlen) 780 { 781 static const unsigned char exporterlabel[] = "exporter"; 782 unsigned char exportsecret[EVP_MAX_MD_SIZE]; 783 unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE]; 784 const EVP_MD *md; 785 EVP_MD_CTX *ctx = EVP_MD_CTX_new(); 786 unsigned int hashsize, datalen; 787 int ret = 0; 788 const SSL_CIPHER *sslcipher; 789 790 if (ctx == NULL || !ossl_statem_export_early_allowed(s)) 791 goto err; 792 793 if (!s->server && s->max_early_data > 0 794 && s->session->ext.max_early_data == 0) 795 sslcipher = SSL_SESSION_get0_cipher(s->psksession); 796 else 797 sslcipher = SSL_SESSION_get0_cipher(s->session); 798 799 md = ssl_md(sslcipher->algorithm2); 800 801 /* 802 * Calculate the hash value and store it in |data|. The reason why 803 * the empty string is used is that the definition of TLS-Exporter 804 * is like so: 805 * 806 * TLS-Exporter(label, context_value, key_length) = 807 * HKDF-Expand-Label(Derive-Secret(Secret, label, ""), 808 * "exporter", Hash(context_value), key_length) 809 * 810 * Derive-Secret(Secret, Label, Messages) = 811 * HKDF-Expand-Label(Secret, Label, 812 * Transcript-Hash(Messages), Hash.length) 813 * 814 * Here Transcript-Hash is the cipher suite hash algorithm. 815 */ 816 if (EVP_DigestInit_ex(ctx, md, NULL) <= 0 817 || EVP_DigestUpdate(ctx, context, contextlen) <= 0 818 || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0 819 || EVP_DigestInit_ex(ctx, md, NULL) <= 0 820 || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0 821 || !tls13_hkdf_expand(s, md, s->early_exporter_master_secret, 822 (const unsigned char *)label, llen, 823 data, datalen, exportsecret, hashsize, 0) 824 || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel, 825 sizeof(exporterlabel) - 1, hash, hashsize, 826 out, olen, 0)) 827 goto err; 828 829 ret = 1; 830 err: 831 EVP_MD_CTX_free(ctx); 832 return ret; 833 } 834