1 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com) 2 * All rights reserved. 3 * 4 * This package is an SSL implementation written 5 * by Eric Young (eay (at) cryptsoft.com). 6 * The implementation was written so as to conform with Netscapes SSL. 7 * 8 * This library is free for commercial and non-commercial use as long as 9 * the following conditions are aheared to. The following conditions 10 * apply to all code found in this distribution, be it the RC4, RSA, 11 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 12 * included with this distribution is covered by the same copyright terms 13 * except that the holder is Tim Hudson (tjh (at) cryptsoft.com). 14 * 15 * Copyright remains Eric Young's, and as such any Copyright notices in 16 * the code are not to be removed. 17 * If this package is used in a product, Eric Young should be given attribution 18 * as the author of the parts of the library used. 19 * This can be in the form of a textual message at program startup or 20 * in documentation (online or textual) provided with the package. 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that the following conditions 24 * are met: 25 * 1. Redistributions of source code must retain the copyright 26 * notice, this list of conditions and the following disclaimer. 27 * 2. Redistributions in binary form must reproduce the above copyright 28 * notice, this list of conditions and the following disclaimer in the 29 * documentation and/or other materials provided with the distribution. 30 * 3. All advertising materials mentioning features or use of this software 31 * must display the following acknowledgement: 32 * "This product includes cryptographic software written by 33 * Eric Young (eay (at) cryptsoft.com)" 34 * The word 'cryptographic' can be left out if the rouines from the library 35 * being used are not cryptographic related :-). 36 * 4. If you include any Windows specific code (or a derivative thereof) from 37 * the apps directory (application code) you must include an acknowledgement: 38 * "This product includes software written by Tim Hudson (tjh (at) cryptsoft.com)" 39 * 40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 43 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 50 * SUCH DAMAGE. 51 * 52 * The licence and distribution terms for any publically available version or 53 * derivative of this code cannot be changed. i.e. this code cannot simply be 54 * copied and put under another distribution licence 55 * [including the GNU Public Licence.] 56 */ 57 /* ==================================================================== 58 * Copyright (c) 1998-2007 The OpenSSL Project. All rights reserved. 59 * 60 * Redistribution and use in source and binary forms, with or without 61 * modification, are permitted provided that the following conditions 62 * are met: 63 * 64 * 1. Redistributions of source code must retain the above copyright 65 * notice, this list of conditions and the following disclaimer. 66 * 67 * 2. Redistributions in binary form must reproduce the above copyright 68 * notice, this list of conditions and the following disclaimer in 69 * the documentation and/or other materials provided with the 70 * distribution. 71 * 72 * 3. All advertising materials mentioning features or use of this 73 * software must display the following acknowledgment: 74 * "This product includes software developed by the OpenSSL Project 75 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" 76 * 77 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 78 * endorse or promote products derived from this software without 79 * prior written permission. For written permission, please contact 80 * openssl-core (at) openssl.org. 81 * 82 * 5. Products derived from this software may not be called "OpenSSL" 83 * nor may "OpenSSL" appear in their names without prior written 84 * permission of the OpenSSL Project. 85 * 86 * 6. Redistributions of any form whatsoever must retain the following 87 * acknowledgment: 88 * "This product includes software developed by the OpenSSL Project 89 * for use in the OpenSSL Toolkit (http://www.openssl.org/)" 90 * 91 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 92 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 93 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 94 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 95 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 96 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 97 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 98 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 99 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 100 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 101 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 102 * OF THE POSSIBILITY OF SUCH DAMAGE. 103 * ==================================================================== 104 * 105 * This product includes cryptographic software written by Eric Young 106 * (eay (at) cryptsoft.com). This product includes software written by Tim 107 * Hudson (tjh (at) cryptsoft.com). */ 108 109 #include <openssl/ssl.h> 110 111 #include <assert.h> 112 #include <limits.h> 113 #include <stdlib.h> 114 #include <string.h> 115 116 #include <openssl/bytestring.h> 117 #include <openssl/digest.h> 118 #include <openssl/err.h> 119 #include <openssl/evp.h> 120 #include <openssl/hmac.h> 121 #include <openssl/mem.h> 122 #include <openssl/nid.h> 123 #include <openssl/rand.h> 124 #include <openssl/type_check.h> 125 126 #include "internal.h" 127 #include "../crypto/internal.h" 128 129 130 static int ssl_check_clienthello_tlsext(SSL_HANDSHAKE *hs); 131 132 static int compare_uint16_t(const void *p1, const void *p2) { 133 uint16_t u1 = *((const uint16_t *)p1); 134 uint16_t u2 = *((const uint16_t *)p2); 135 if (u1 < u2) { 136 return -1; 137 } else if (u1 > u2) { 138 return 1; 139 } else { 140 return 0; 141 } 142 } 143 144 /* Per http://tools.ietf.org/html/rfc5246#section-7.4.1.4, there may not be 145 * more than one extension of the same type in a ClientHello or ServerHello. 146 * This function does an initial scan over the extensions block to filter those 147 * out. */ 148 static int tls1_check_duplicate_extensions(const CBS *cbs) { 149 CBS extensions = *cbs; 150 size_t num_extensions = 0, i = 0; 151 uint16_t *extension_types = NULL; 152 int ret = 0; 153 154 /* First pass: count the extensions. */ 155 while (CBS_len(&extensions) > 0) { 156 uint16_t type; 157 CBS extension; 158 159 if (!CBS_get_u16(&extensions, &type) || 160 !CBS_get_u16_length_prefixed(&extensions, &extension)) { 161 goto done; 162 } 163 164 num_extensions++; 165 } 166 167 if (num_extensions == 0) { 168 return 1; 169 } 170 171 extension_types = OPENSSL_malloc(sizeof(uint16_t) * num_extensions); 172 if (extension_types == NULL) { 173 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); 174 goto done; 175 } 176 177 /* Second pass: gather the extension types. */ 178 extensions = *cbs; 179 for (i = 0; i < num_extensions; i++) { 180 CBS extension; 181 182 if (!CBS_get_u16(&extensions, &extension_types[i]) || 183 !CBS_get_u16_length_prefixed(&extensions, &extension)) { 184 /* This should not happen. */ 185 goto done; 186 } 187 } 188 assert(CBS_len(&extensions) == 0); 189 190 /* Sort the extensions and make sure there are no duplicates. */ 191 qsort(extension_types, num_extensions, sizeof(uint16_t), compare_uint16_t); 192 for (i = 1; i < num_extensions; i++) { 193 if (extension_types[i - 1] == extension_types[i]) { 194 goto done; 195 } 196 } 197 198 ret = 1; 199 200 done: 201 OPENSSL_free(extension_types); 202 return ret; 203 } 204 205 int ssl_client_hello_init(SSL *ssl, SSL_CLIENT_HELLO *out, const uint8_t *in, 206 size_t in_len) { 207 OPENSSL_memset(out, 0, sizeof(*out)); 208 out->ssl = ssl; 209 out->client_hello = in; 210 out->client_hello_len = in_len; 211 212 CBS client_hello, random, session_id; 213 CBS_init(&client_hello, out->client_hello, out->client_hello_len); 214 if (!CBS_get_u16(&client_hello, &out->version) || 215 !CBS_get_bytes(&client_hello, &random, SSL3_RANDOM_SIZE) || 216 !CBS_get_u8_length_prefixed(&client_hello, &session_id) || 217 CBS_len(&session_id) > SSL_MAX_SSL_SESSION_ID_LENGTH) { 218 return 0; 219 } 220 221 out->random = CBS_data(&random); 222 out->random_len = CBS_len(&random); 223 out->session_id = CBS_data(&session_id); 224 out->session_id_len = CBS_len(&session_id); 225 226 /* Skip past DTLS cookie */ 227 if (SSL_is_dtls(out->ssl)) { 228 CBS cookie; 229 if (!CBS_get_u8_length_prefixed(&client_hello, &cookie) || 230 CBS_len(&cookie) > DTLS1_COOKIE_LENGTH) { 231 return 0; 232 } 233 } 234 235 CBS cipher_suites, compression_methods; 236 if (!CBS_get_u16_length_prefixed(&client_hello, &cipher_suites) || 237 CBS_len(&cipher_suites) < 2 || (CBS_len(&cipher_suites) & 1) != 0 || 238 !CBS_get_u8_length_prefixed(&client_hello, &compression_methods) || 239 CBS_len(&compression_methods) < 1) { 240 return 0; 241 } 242 243 out->cipher_suites = CBS_data(&cipher_suites); 244 out->cipher_suites_len = CBS_len(&cipher_suites); 245 out->compression_methods = CBS_data(&compression_methods); 246 out->compression_methods_len = CBS_len(&compression_methods); 247 248 /* If the ClientHello ends here then it's valid, but doesn't have any 249 * extensions. (E.g. SSLv3.) */ 250 if (CBS_len(&client_hello) == 0) { 251 out->extensions = NULL; 252 out->extensions_len = 0; 253 return 1; 254 } 255 256 /* Extract extensions and check it is valid. */ 257 CBS extensions; 258 if (!CBS_get_u16_length_prefixed(&client_hello, &extensions) || 259 !tls1_check_duplicate_extensions(&extensions) || 260 CBS_len(&client_hello) != 0) { 261 return 0; 262 } 263 264 out->extensions = CBS_data(&extensions); 265 out->extensions_len = CBS_len(&extensions); 266 267 return 1; 268 } 269 270 int ssl_client_hello_get_extension(const SSL_CLIENT_HELLO *client_hello, 271 CBS *out, uint16_t extension_type) { 272 CBS extensions; 273 CBS_init(&extensions, client_hello->extensions, client_hello->extensions_len); 274 while (CBS_len(&extensions) != 0) { 275 /* Decode the next extension. */ 276 uint16_t type; 277 CBS extension; 278 if (!CBS_get_u16(&extensions, &type) || 279 !CBS_get_u16_length_prefixed(&extensions, &extension)) { 280 return 0; 281 } 282 283 if (type == extension_type) { 284 *out = extension; 285 return 1; 286 } 287 } 288 289 return 0; 290 } 291 292 int SSL_early_callback_ctx_extension_get(const SSL_CLIENT_HELLO *client_hello, 293 uint16_t extension_type, 294 const uint8_t **out_data, 295 size_t *out_len) { 296 CBS cbs; 297 if (!ssl_client_hello_get_extension(client_hello, &cbs, extension_type)) { 298 return 0; 299 } 300 301 *out_data = CBS_data(&cbs); 302 *out_len = CBS_len(&cbs); 303 return 1; 304 } 305 306 static const uint16_t kDefaultGroups[] = { 307 SSL_CURVE_X25519, 308 SSL_CURVE_SECP256R1, 309 SSL_CURVE_SECP384R1, 310 }; 311 312 void tls1_get_grouplist(SSL *ssl, const uint16_t **out_group_ids, 313 size_t *out_group_ids_len) { 314 *out_group_ids = ssl->supported_group_list; 315 *out_group_ids_len = ssl->supported_group_list_len; 316 if (!*out_group_ids) { 317 *out_group_ids = kDefaultGroups; 318 *out_group_ids_len = OPENSSL_ARRAY_SIZE(kDefaultGroups); 319 } 320 } 321 322 int tls1_get_shared_group(SSL_HANDSHAKE *hs, uint16_t *out_group_id) { 323 SSL *const ssl = hs->ssl; 324 assert(ssl->server); 325 326 const uint16_t *groups, *pref, *supp; 327 size_t groups_len, pref_len, supp_len; 328 tls1_get_grouplist(ssl, &groups, &groups_len); 329 330 /* Clients are not required to send a supported_groups extension. In this 331 * case, the server is free to pick any group it likes. See RFC 4492, 332 * section 4, paragraph 3. 333 * 334 * However, in the interests of compatibility, we will skip ECDH if the 335 * client didn't send an extension because we can't be sure that they'll 336 * support our favoured group. Thus we do not special-case an emtpy 337 * |peer_supported_group_list|. */ 338 339 if (ssl->options & SSL_OP_CIPHER_SERVER_PREFERENCE) { 340 pref = groups; 341 pref_len = groups_len; 342 supp = hs->peer_supported_group_list; 343 supp_len = hs->peer_supported_group_list_len; 344 } else { 345 pref = hs->peer_supported_group_list; 346 pref_len = hs->peer_supported_group_list_len; 347 supp = groups; 348 supp_len = groups_len; 349 } 350 351 for (size_t i = 0; i < pref_len; i++) { 352 for (size_t j = 0; j < supp_len; j++) { 353 if (pref[i] == supp[j]) { 354 *out_group_id = pref[i]; 355 return 1; 356 } 357 } 358 } 359 360 return 0; 361 } 362 363 int tls1_set_curves(uint16_t **out_group_ids, size_t *out_group_ids_len, 364 const int *curves, size_t ncurves) { 365 uint16_t *group_ids; 366 367 group_ids = OPENSSL_malloc(ncurves * sizeof(uint16_t)); 368 if (group_ids == NULL) { 369 return 0; 370 } 371 372 for (size_t i = 0; i < ncurves; i++) { 373 if (!ssl_nid_to_group_id(&group_ids[i], curves[i])) { 374 OPENSSL_free(group_ids); 375 return 0; 376 } 377 } 378 379 OPENSSL_free(*out_group_ids); 380 *out_group_ids = group_ids; 381 *out_group_ids_len = ncurves; 382 383 return 1; 384 } 385 386 int tls1_set_curves_list(uint16_t **out_group_ids, size_t *out_group_ids_len, 387 const char *curves) { 388 uint16_t *group_ids = NULL; 389 size_t ncurves = 0; 390 391 const char *col; 392 const char *ptr = curves; 393 394 do { 395 col = strchr(ptr, ':'); 396 397 uint16_t group_id; 398 if (!ssl_name_to_group_id(&group_id, ptr, 399 col ? (size_t)(col - ptr) : strlen(ptr))) { 400 goto err; 401 } 402 403 uint16_t *new_group_ids = OPENSSL_realloc(group_ids, 404 (ncurves + 1) * sizeof(uint16_t)); 405 if (new_group_ids == NULL) { 406 goto err; 407 } 408 group_ids = new_group_ids; 409 410 group_ids[ncurves] = group_id; 411 ncurves++; 412 413 if (col) { 414 ptr = col + 1; 415 } 416 } while (col); 417 418 OPENSSL_free(*out_group_ids); 419 *out_group_ids = group_ids; 420 *out_group_ids_len = ncurves; 421 422 return 1; 423 424 err: 425 OPENSSL_free(group_ids); 426 return 0; 427 } 428 429 int tls1_check_group_id(SSL *ssl, uint16_t group_id) { 430 const uint16_t *groups; 431 size_t groups_len; 432 tls1_get_grouplist(ssl, &groups, &groups_len); 433 for (size_t i = 0; i < groups_len; i++) { 434 if (groups[i] == group_id) { 435 return 1; 436 } 437 } 438 439 return 0; 440 } 441 442 /* kVerifySignatureAlgorithms is the default list of accepted signature 443 * algorithms for verifying. 444 * 445 * For now, RSA-PSS signature algorithms are not enabled on Android's system 446 * BoringSSL. Once the change in Chrome has stuck and the values are finalized, 447 * restore them. */ 448 static const uint16_t kVerifySignatureAlgorithms[] = { 449 /* Prefer SHA-256 algorithms. */ 450 SSL_SIGN_ECDSA_SECP256R1_SHA256, 451 #if !defined(BORINGSSL_ANDROID_SYSTEM) 452 SSL_SIGN_RSA_PSS_SHA256, 453 #endif 454 SSL_SIGN_RSA_PKCS1_SHA256, 455 456 /* Larger hashes are acceptable. */ 457 SSL_SIGN_ECDSA_SECP384R1_SHA384, 458 #if !defined(BORINGSSL_ANDROID_SYSTEM) 459 SSL_SIGN_RSA_PSS_SHA384, 460 #endif 461 SSL_SIGN_RSA_PKCS1_SHA384, 462 463 /* TODO(davidben): Remove this. */ 464 #if defined(BORINGSSL_ANDROID_SYSTEM) 465 SSL_SIGN_ECDSA_SECP521R1_SHA512, 466 #endif 467 #if !defined(BORINGSSL_ANDROID_SYSTEM) 468 SSL_SIGN_RSA_PSS_SHA512, 469 #endif 470 SSL_SIGN_RSA_PKCS1_SHA512, 471 472 /* For now, SHA-1 is still accepted but least preferable. */ 473 SSL_SIGN_RSA_PKCS1_SHA1, 474 475 }; 476 477 /* kSignSignatureAlgorithms is the default list of supported signature 478 * algorithms for signing. 479 * 480 * For now, RSA-PSS signature algorithms are not enabled on Android's system 481 * BoringSSL. Once the change in Chrome has stuck and the values are finalized, 482 * restore them. */ 483 static const uint16_t kSignSignatureAlgorithms[] = { 484 /* Prefer SHA-256 algorithms. */ 485 SSL_SIGN_ECDSA_SECP256R1_SHA256, 486 #if !defined(BORINGSSL_ANDROID_SYSTEM) 487 SSL_SIGN_RSA_PSS_SHA256, 488 #endif 489 SSL_SIGN_RSA_PKCS1_SHA256, 490 491 /* If needed, sign larger hashes. 492 * 493 * TODO(davidben): Determine which of these may be pruned. */ 494 SSL_SIGN_ECDSA_SECP384R1_SHA384, 495 #if !defined(BORINGSSL_ANDROID_SYSTEM) 496 SSL_SIGN_RSA_PSS_SHA384, 497 #endif 498 SSL_SIGN_RSA_PKCS1_SHA384, 499 500 SSL_SIGN_ECDSA_SECP521R1_SHA512, 501 #if !defined(BORINGSSL_ANDROID_SYSTEM) 502 SSL_SIGN_RSA_PSS_SHA512, 503 #endif 504 SSL_SIGN_RSA_PKCS1_SHA512, 505 506 /* If the peer supports nothing else, sign with SHA-1. */ 507 SSL_SIGN_ECDSA_SHA1, 508 SSL_SIGN_RSA_PKCS1_SHA1, 509 }; 510 511 size_t tls12_get_verify_sigalgs(const SSL *ssl, const uint16_t **out) { 512 *out = kVerifySignatureAlgorithms; 513 return OPENSSL_ARRAY_SIZE(kVerifySignatureAlgorithms); 514 } 515 516 int tls12_check_peer_sigalg(SSL *ssl, int *out_alert, uint16_t sigalg) { 517 const uint16_t *verify_sigalgs; 518 size_t num_verify_sigalgs = tls12_get_verify_sigalgs(ssl, &verify_sigalgs); 519 for (size_t i = 0; i < num_verify_sigalgs; i++) { 520 if (sigalg == verify_sigalgs[i]) { 521 return 1; 522 } 523 } 524 525 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SIGNATURE_TYPE); 526 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 527 return 0; 528 } 529 530 /* tls_extension represents a TLS extension that is handled internally. The 531 * |init| function is called for each handshake, before any other functions of 532 * the extension. Then the add and parse callbacks are called as needed. 533 * 534 * The parse callbacks receive a |CBS| that contains the contents of the 535 * extension (i.e. not including the type and length bytes). If an extension is 536 * not received then the parse callbacks will be called with a NULL CBS so that 537 * they can do any processing needed to handle the absence of an extension. 538 * 539 * The add callbacks receive a |CBB| to which the extension can be appended but 540 * the function is responsible for appending the type and length bytes too. 541 * 542 * All callbacks return one for success and zero for error. If a parse function 543 * returns zero then a fatal alert with value |*out_alert| will be sent. If 544 * |*out_alert| isn't set, then a |decode_error| alert will be sent. */ 545 struct tls_extension { 546 uint16_t value; 547 void (*init)(SSL_HANDSHAKE *hs); 548 549 int (*add_clienthello)(SSL_HANDSHAKE *hs, CBB *out); 550 int (*parse_serverhello)(SSL_HANDSHAKE *hs, uint8_t *out_alert, 551 CBS *contents); 552 553 int (*parse_clienthello)(SSL_HANDSHAKE *hs, uint8_t *out_alert, 554 CBS *contents); 555 int (*add_serverhello)(SSL_HANDSHAKE *hs, CBB *out); 556 }; 557 558 static int forbid_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 559 CBS *contents) { 560 if (contents != NULL) { 561 /* Servers MUST NOT send this extension. */ 562 *out_alert = SSL_AD_UNSUPPORTED_EXTENSION; 563 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION); 564 return 0; 565 } 566 567 return 1; 568 } 569 570 static int ignore_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 571 CBS *contents) { 572 /* This extension from the client is handled elsewhere. */ 573 return 1; 574 } 575 576 static int dont_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 577 return 1; 578 } 579 580 /* Server name indication (SNI). 581 * 582 * https://tools.ietf.org/html/rfc6066#section-3. */ 583 584 static int ext_sni_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 585 SSL *const ssl = hs->ssl; 586 if (ssl->tlsext_hostname == NULL) { 587 return 1; 588 } 589 590 CBB contents, server_name_list, name; 591 if (!CBB_add_u16(out, TLSEXT_TYPE_server_name) || 592 !CBB_add_u16_length_prefixed(out, &contents) || 593 !CBB_add_u16_length_prefixed(&contents, &server_name_list) || 594 !CBB_add_u8(&server_name_list, TLSEXT_NAMETYPE_host_name) || 595 !CBB_add_u16_length_prefixed(&server_name_list, &name) || 596 !CBB_add_bytes(&name, (const uint8_t *)ssl->tlsext_hostname, 597 strlen(ssl->tlsext_hostname)) || 598 !CBB_flush(out)) { 599 return 0; 600 } 601 602 return 1; 603 } 604 605 static int ext_sni_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 606 CBS *contents) { 607 SSL *const ssl = hs->ssl; 608 if (contents == NULL) { 609 return 1; 610 } 611 612 if (CBS_len(contents) != 0) { 613 return 0; 614 } 615 616 assert(ssl->tlsext_hostname != NULL); 617 618 if (ssl->session == NULL) { 619 OPENSSL_free(hs->new_session->tlsext_hostname); 620 hs->new_session->tlsext_hostname = BUF_strdup(ssl->tlsext_hostname); 621 if (!hs->new_session->tlsext_hostname) { 622 *out_alert = SSL_AD_INTERNAL_ERROR; 623 return 0; 624 } 625 } 626 627 return 1; 628 } 629 630 static int ext_sni_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 631 CBS *contents) { 632 if (contents == NULL) { 633 return 1; 634 } 635 636 CBS server_name_list, host_name; 637 uint8_t name_type; 638 if (!CBS_get_u16_length_prefixed(contents, &server_name_list) || 639 !CBS_get_u8(&server_name_list, &name_type) || 640 /* Although the server_name extension was intended to be extensible to 641 * new name types and multiple names, OpenSSL 1.0.x had a bug which meant 642 * different name types will cause an error. Further, RFC 4366 originally 643 * defined syntax inextensibly. RFC 6066 corrected this mistake, but 644 * adding new name types is no longer feasible. 645 * 646 * Act as if the extensibility does not exist to simplify parsing. */ 647 !CBS_get_u16_length_prefixed(&server_name_list, &host_name) || 648 CBS_len(&server_name_list) != 0 || 649 CBS_len(contents) != 0) { 650 return 0; 651 } 652 653 if (name_type != TLSEXT_NAMETYPE_host_name || 654 CBS_len(&host_name) == 0 || 655 CBS_len(&host_name) > TLSEXT_MAXLEN_host_name || 656 CBS_contains_zero_byte(&host_name)) { 657 *out_alert = SSL_AD_UNRECOGNIZED_NAME; 658 return 0; 659 } 660 661 /* Copy the hostname as a string. */ 662 if (!CBS_strdup(&host_name, &hs->hostname)) { 663 *out_alert = SSL_AD_INTERNAL_ERROR; 664 return 0; 665 } 666 667 hs->should_ack_sni = 1; 668 return 1; 669 } 670 671 static int ext_sni_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 672 if (hs->ssl->s3->session_reused || 673 !hs->should_ack_sni) { 674 return 1; 675 } 676 677 if (!CBB_add_u16(out, TLSEXT_TYPE_server_name) || 678 !CBB_add_u16(out, 0 /* length */)) { 679 return 0; 680 } 681 682 return 1; 683 } 684 685 686 /* Renegotiation indication. 687 * 688 * https://tools.ietf.org/html/rfc5746 */ 689 690 static int ext_ri_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 691 SSL *const ssl = hs->ssl; 692 uint16_t min_version, max_version; 693 if (!ssl_get_version_range(ssl, &min_version, &max_version)) { 694 return 0; 695 } 696 697 /* Renegotiation indication is not necessary in TLS 1.3. */ 698 if (min_version >= TLS1_3_VERSION) { 699 return 1; 700 } 701 702 assert(ssl->s3->initial_handshake_complete == 703 (ssl->s3->previous_client_finished_len != 0)); 704 705 CBB contents, prev_finished; 706 if (!CBB_add_u16(out, TLSEXT_TYPE_renegotiate) || 707 !CBB_add_u16_length_prefixed(out, &contents) || 708 !CBB_add_u8_length_prefixed(&contents, &prev_finished) || 709 !CBB_add_bytes(&prev_finished, ssl->s3->previous_client_finished, 710 ssl->s3->previous_client_finished_len) || 711 !CBB_flush(out)) { 712 return 0; 713 } 714 715 return 1; 716 } 717 718 static int ext_ri_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 719 CBS *contents) { 720 SSL *const ssl = hs->ssl; 721 if (contents != NULL && ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 722 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 723 return 0; 724 } 725 726 /* Servers may not switch between omitting the extension and supporting it. 727 * See RFC 5746, sections 3.5 and 4.2. */ 728 if (ssl->s3->initial_handshake_complete && 729 (contents != NULL) != ssl->s3->send_connection_binding) { 730 *out_alert = SSL_AD_HANDSHAKE_FAILURE; 731 OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH); 732 return 0; 733 } 734 735 if (contents == NULL) { 736 /* Strictly speaking, if we want to avoid an attack we should *always* see 737 * RI even on initial ServerHello because the client doesn't see any 738 * renegotiation during an attack. However this would mean we could not 739 * connect to any server which doesn't support RI. 740 * 741 * OpenSSL has |SSL_OP_LEGACY_SERVER_CONNECT| to control this, but in 742 * practical terms every client sets it so it's just assumed here. */ 743 return 1; 744 } 745 746 const size_t expected_len = ssl->s3->previous_client_finished_len + 747 ssl->s3->previous_server_finished_len; 748 749 /* Check for logic errors */ 750 assert(!expected_len || ssl->s3->previous_client_finished_len); 751 assert(!expected_len || ssl->s3->previous_server_finished_len); 752 assert(ssl->s3->initial_handshake_complete == 753 (ssl->s3->previous_client_finished_len != 0)); 754 assert(ssl->s3->initial_handshake_complete == 755 (ssl->s3->previous_server_finished_len != 0)); 756 757 /* Parse out the extension contents. */ 758 CBS renegotiated_connection; 759 if (!CBS_get_u8_length_prefixed(contents, &renegotiated_connection) || 760 CBS_len(contents) != 0) { 761 OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_ENCODING_ERR); 762 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 763 return 0; 764 } 765 766 /* Check that the extension matches. */ 767 if (CBS_len(&renegotiated_connection) != expected_len) { 768 OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH); 769 *out_alert = SSL_AD_HANDSHAKE_FAILURE; 770 return 0; 771 } 772 773 const uint8_t *d = CBS_data(&renegotiated_connection); 774 if (CRYPTO_memcmp(d, ssl->s3->previous_client_finished, 775 ssl->s3->previous_client_finished_len)) { 776 OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH); 777 *out_alert = SSL_AD_HANDSHAKE_FAILURE; 778 return 0; 779 } 780 d += ssl->s3->previous_client_finished_len; 781 782 if (CRYPTO_memcmp(d, ssl->s3->previous_server_finished, 783 ssl->s3->previous_server_finished_len)) { 784 OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH); 785 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 786 return 0; 787 } 788 ssl->s3->send_connection_binding = 1; 789 790 return 1; 791 } 792 793 static int ext_ri_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 794 CBS *contents) { 795 SSL *const ssl = hs->ssl; 796 /* Renegotiation isn't supported as a server so this function should never be 797 * called after the initial handshake. */ 798 assert(!ssl->s3->initial_handshake_complete); 799 800 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 801 return 1; 802 } 803 804 if (contents == NULL) { 805 return 1; 806 } 807 808 CBS renegotiated_connection; 809 if (!CBS_get_u8_length_prefixed(contents, &renegotiated_connection) || 810 CBS_len(contents) != 0) { 811 OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_ENCODING_ERR); 812 return 0; 813 } 814 815 /* Check that the extension matches. We do not support renegotiation as a 816 * server, so this must be empty. */ 817 if (CBS_len(&renegotiated_connection) != 0) { 818 OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH); 819 *out_alert = SSL_AD_HANDSHAKE_FAILURE; 820 return 0; 821 } 822 823 ssl->s3->send_connection_binding = 1; 824 825 return 1; 826 } 827 828 static int ext_ri_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 829 SSL *const ssl = hs->ssl; 830 /* Renegotiation isn't supported as a server so this function should never be 831 * called after the initial handshake. */ 832 assert(!ssl->s3->initial_handshake_complete); 833 834 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 835 return 1; 836 } 837 838 if (!CBB_add_u16(out, TLSEXT_TYPE_renegotiate) || 839 !CBB_add_u16(out, 1 /* length */) || 840 !CBB_add_u8(out, 0 /* empty renegotiation info */)) { 841 return 0; 842 } 843 844 return 1; 845 } 846 847 848 /* Extended Master Secret. 849 * 850 * https://tools.ietf.org/html/rfc7627 */ 851 852 static int ext_ems_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 853 uint16_t min_version, max_version; 854 if (!ssl_get_version_range(hs->ssl, &min_version, &max_version)) { 855 return 0; 856 } 857 858 /* Extended master secret is not necessary in TLS 1.3. */ 859 if (min_version >= TLS1_3_VERSION || max_version <= SSL3_VERSION) { 860 return 1; 861 } 862 863 if (!CBB_add_u16(out, TLSEXT_TYPE_extended_master_secret) || 864 !CBB_add_u16(out, 0 /* length */)) { 865 return 0; 866 } 867 868 return 1; 869 } 870 871 static int ext_ems_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 872 CBS *contents) { 873 SSL *const ssl = hs->ssl; 874 875 if (contents != NULL) { 876 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION || 877 ssl->version == SSL3_VERSION || 878 CBS_len(contents) != 0) { 879 return 0; 880 } 881 882 hs->extended_master_secret = 1; 883 } 884 885 /* Whether EMS is negotiated may not change on renegotiation. */ 886 if (ssl->s3->established_session != NULL && 887 hs->extended_master_secret != 888 ssl->s3->established_session->extended_master_secret) { 889 OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_EMS_MISMATCH); 890 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 891 return 0; 892 } 893 894 return 1; 895 } 896 897 static int ext_ems_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 898 CBS *contents) { 899 uint16_t version = ssl3_protocol_version(hs->ssl); 900 if (version >= TLS1_3_VERSION || 901 version == SSL3_VERSION) { 902 return 1; 903 } 904 905 if (contents == NULL) { 906 return 1; 907 } 908 909 if (CBS_len(contents) != 0) { 910 return 0; 911 } 912 913 hs->extended_master_secret = 1; 914 return 1; 915 } 916 917 static int ext_ems_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 918 if (!hs->extended_master_secret) { 919 return 1; 920 } 921 922 if (!CBB_add_u16(out, TLSEXT_TYPE_extended_master_secret) || 923 !CBB_add_u16(out, 0 /* length */)) { 924 return 0; 925 } 926 927 return 1; 928 } 929 930 931 /* Session tickets. 932 * 933 * https://tools.ietf.org/html/rfc5077 */ 934 935 static int ext_ticket_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 936 SSL *const ssl = hs->ssl; 937 uint16_t min_version, max_version; 938 if (!ssl_get_version_range(ssl, &min_version, &max_version)) { 939 return 0; 940 } 941 942 /* TLS 1.3 uses a different ticket extension. */ 943 if (min_version >= TLS1_3_VERSION || 944 SSL_get_options(ssl) & SSL_OP_NO_TICKET) { 945 return 1; 946 } 947 948 const uint8_t *ticket_data = NULL; 949 int ticket_len = 0; 950 951 /* Renegotiation does not participate in session resumption. However, still 952 * advertise the extension to avoid potentially breaking servers which carry 953 * over the state from the previous handshake, such as OpenSSL servers 954 * without upstream's 3c3f0259238594d77264a78944d409f2127642c4. */ 955 uint16_t session_version; 956 if (!ssl->s3->initial_handshake_complete && 957 ssl->session != NULL && 958 ssl->session->tlsext_tick != NULL && 959 /* Don't send TLS 1.3 session tickets in the ticket extension. */ 960 ssl->method->version_from_wire(&session_version, 961 ssl->session->ssl_version) && 962 session_version < TLS1_3_VERSION) { 963 ticket_data = ssl->session->tlsext_tick; 964 ticket_len = ssl->session->tlsext_ticklen; 965 } 966 967 CBB ticket; 968 if (!CBB_add_u16(out, TLSEXT_TYPE_session_ticket) || 969 !CBB_add_u16_length_prefixed(out, &ticket) || 970 !CBB_add_bytes(&ticket, ticket_data, ticket_len) || 971 !CBB_flush(out)) { 972 return 0; 973 } 974 975 return 1; 976 } 977 978 static int ext_ticket_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 979 CBS *contents) { 980 SSL *const ssl = hs->ssl; 981 if (contents == NULL) { 982 return 1; 983 } 984 985 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 986 return 0; 987 } 988 989 /* If |SSL_OP_NO_TICKET| is set then no extension will have been sent and 990 * this function should never be called, even if the server tries to send the 991 * extension. */ 992 assert((SSL_get_options(ssl) & SSL_OP_NO_TICKET) == 0); 993 994 if (CBS_len(contents) != 0) { 995 return 0; 996 } 997 998 hs->ticket_expected = 1; 999 return 1; 1000 } 1001 1002 static int ext_ticket_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 1003 if (!hs->ticket_expected) { 1004 return 1; 1005 } 1006 1007 /* If |SSL_OP_NO_TICKET| is set, |ticket_expected| should never be true. */ 1008 assert((SSL_get_options(hs->ssl) & SSL_OP_NO_TICKET) == 0); 1009 1010 if (!CBB_add_u16(out, TLSEXT_TYPE_session_ticket) || 1011 !CBB_add_u16(out, 0 /* length */)) { 1012 return 0; 1013 } 1014 1015 return 1; 1016 } 1017 1018 1019 /* Signature Algorithms. 1020 * 1021 * https://tools.ietf.org/html/rfc5246#section-7.4.1.4.1 */ 1022 1023 static int ext_sigalgs_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 1024 SSL *const ssl = hs->ssl; 1025 uint16_t min_version, max_version; 1026 if (!ssl_get_version_range(ssl, &min_version, &max_version)) { 1027 return 0; 1028 } 1029 1030 if (max_version < TLS1_2_VERSION) { 1031 return 1; 1032 } 1033 1034 const uint16_t *sigalgs; 1035 const size_t num_sigalgs = tls12_get_verify_sigalgs(ssl, &sigalgs); 1036 1037 CBB contents, sigalgs_cbb; 1038 if (!CBB_add_u16(out, TLSEXT_TYPE_signature_algorithms) || 1039 !CBB_add_u16_length_prefixed(out, &contents) || 1040 !CBB_add_u16_length_prefixed(&contents, &sigalgs_cbb)) { 1041 return 0; 1042 } 1043 1044 for (size_t i = 0; i < num_sigalgs; i++) { 1045 if (!CBB_add_u16(&sigalgs_cbb, sigalgs[i])) { 1046 return 0; 1047 } 1048 } 1049 1050 if (!CBB_flush(out)) { 1051 return 0; 1052 } 1053 1054 return 1; 1055 } 1056 1057 static int ext_sigalgs_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1058 CBS *contents) { 1059 OPENSSL_free(hs->peer_sigalgs); 1060 hs->peer_sigalgs = NULL; 1061 hs->num_peer_sigalgs = 0; 1062 1063 if (contents == NULL) { 1064 return 1; 1065 } 1066 1067 CBS supported_signature_algorithms; 1068 if (!CBS_get_u16_length_prefixed(contents, &supported_signature_algorithms) || 1069 CBS_len(contents) != 0 || 1070 CBS_len(&supported_signature_algorithms) == 0 || 1071 !tls1_parse_peer_sigalgs(hs, &supported_signature_algorithms)) { 1072 return 0; 1073 } 1074 1075 return 1; 1076 } 1077 1078 1079 /* OCSP Stapling. 1080 * 1081 * https://tools.ietf.org/html/rfc6066#section-8 */ 1082 1083 static int ext_ocsp_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 1084 SSL *const ssl = hs->ssl; 1085 if (!ssl->ocsp_stapling_enabled) { 1086 return 1; 1087 } 1088 1089 CBB contents; 1090 if (!CBB_add_u16(out, TLSEXT_TYPE_status_request) || 1091 !CBB_add_u16_length_prefixed(out, &contents) || 1092 !CBB_add_u8(&contents, TLSEXT_STATUSTYPE_ocsp) || 1093 !CBB_add_u16(&contents, 0 /* empty responder ID list */) || 1094 !CBB_add_u16(&contents, 0 /* empty request extensions */) || 1095 !CBB_flush(out)) { 1096 return 0; 1097 } 1098 1099 return 1; 1100 } 1101 1102 static int ext_ocsp_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1103 CBS *contents) { 1104 SSL *const ssl = hs->ssl; 1105 if (contents == NULL) { 1106 return 1; 1107 } 1108 1109 /* TLS 1.3 OCSP responses are included in the Certificate extensions. */ 1110 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 1111 return 0; 1112 } 1113 1114 /* OCSP stapling is forbidden on non-certificate ciphers. */ 1115 if (CBS_len(contents) != 0 || 1116 !ssl_cipher_uses_certificate_auth(hs->new_cipher)) { 1117 return 0; 1118 } 1119 1120 /* Note this does not check for resumption in TLS 1.2. Sending 1121 * status_request here does not make sense, but OpenSSL does so and the 1122 * specification does not say anything. Tolerate it but ignore it. */ 1123 1124 hs->certificate_status_expected = 1; 1125 return 1; 1126 } 1127 1128 static int ext_ocsp_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1129 CBS *contents) { 1130 if (contents == NULL) { 1131 return 1; 1132 } 1133 1134 uint8_t status_type; 1135 if (!CBS_get_u8(contents, &status_type)) { 1136 return 0; 1137 } 1138 1139 /* We cannot decide whether OCSP stapling will occur yet because the correct 1140 * SSL_CTX might not have been selected. */ 1141 hs->ocsp_stapling_requested = status_type == TLSEXT_STATUSTYPE_ocsp; 1142 1143 return 1; 1144 } 1145 1146 static int ext_ocsp_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 1147 SSL *const ssl = hs->ssl; 1148 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION || 1149 !hs->ocsp_stapling_requested || 1150 ssl->cert->ocsp_response == NULL || 1151 ssl->s3->session_reused || 1152 !ssl_cipher_uses_certificate_auth(hs->new_cipher)) { 1153 return 1; 1154 } 1155 1156 hs->certificate_status_expected = 1; 1157 1158 return CBB_add_u16(out, TLSEXT_TYPE_status_request) && 1159 CBB_add_u16(out, 0 /* length */); 1160 } 1161 1162 1163 /* Next protocol negotiation. 1164 * 1165 * https://htmlpreview.github.io/?https://github.com/agl/technotes/blob/master/nextprotoneg.html */ 1166 1167 static int ext_npn_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 1168 SSL *const ssl = hs->ssl; 1169 if (ssl->s3->initial_handshake_complete || 1170 ssl->ctx->next_proto_select_cb == NULL || 1171 SSL_is_dtls(ssl)) { 1172 return 1; 1173 } 1174 1175 if (!CBB_add_u16(out, TLSEXT_TYPE_next_proto_neg) || 1176 !CBB_add_u16(out, 0 /* length */)) { 1177 return 0; 1178 } 1179 1180 return 1; 1181 } 1182 1183 static int ext_npn_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1184 CBS *contents) { 1185 SSL *const ssl = hs->ssl; 1186 if (contents == NULL) { 1187 return 1; 1188 } 1189 1190 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 1191 return 0; 1192 } 1193 1194 /* If any of these are false then we should never have sent the NPN 1195 * extension in the ClientHello and thus this function should never have been 1196 * called. */ 1197 assert(!ssl->s3->initial_handshake_complete); 1198 assert(!SSL_is_dtls(ssl)); 1199 assert(ssl->ctx->next_proto_select_cb != NULL); 1200 1201 if (ssl->s3->alpn_selected != NULL) { 1202 /* NPN and ALPN may not be negotiated in the same connection. */ 1203 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 1204 OPENSSL_PUT_ERROR(SSL, SSL_R_NEGOTIATED_BOTH_NPN_AND_ALPN); 1205 return 0; 1206 } 1207 1208 const uint8_t *const orig_contents = CBS_data(contents); 1209 const size_t orig_len = CBS_len(contents); 1210 1211 while (CBS_len(contents) != 0) { 1212 CBS proto; 1213 if (!CBS_get_u8_length_prefixed(contents, &proto) || 1214 CBS_len(&proto) == 0) { 1215 return 0; 1216 } 1217 } 1218 1219 uint8_t *selected; 1220 uint8_t selected_len; 1221 if (ssl->ctx->next_proto_select_cb( 1222 ssl, &selected, &selected_len, orig_contents, orig_len, 1223 ssl->ctx->next_proto_select_cb_arg) != SSL_TLSEXT_ERR_OK) { 1224 *out_alert = SSL_AD_INTERNAL_ERROR; 1225 return 0; 1226 } 1227 1228 OPENSSL_free(ssl->s3->next_proto_negotiated); 1229 ssl->s3->next_proto_negotiated = BUF_memdup(selected, selected_len); 1230 if (ssl->s3->next_proto_negotiated == NULL) { 1231 *out_alert = SSL_AD_INTERNAL_ERROR; 1232 return 0; 1233 } 1234 1235 ssl->s3->next_proto_negotiated_len = selected_len; 1236 hs->next_proto_neg_seen = 1; 1237 1238 return 1; 1239 } 1240 1241 static int ext_npn_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1242 CBS *contents) { 1243 SSL *const ssl = hs->ssl; 1244 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 1245 return 1; 1246 } 1247 1248 if (contents != NULL && CBS_len(contents) != 0) { 1249 return 0; 1250 } 1251 1252 if (contents == NULL || 1253 ssl->s3->initial_handshake_complete || 1254 ssl->ctx->next_protos_advertised_cb == NULL || 1255 SSL_is_dtls(ssl)) { 1256 return 1; 1257 } 1258 1259 hs->next_proto_neg_seen = 1; 1260 return 1; 1261 } 1262 1263 static int ext_npn_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 1264 SSL *const ssl = hs->ssl; 1265 /* |next_proto_neg_seen| might have been cleared when an ALPN extension was 1266 * parsed. */ 1267 if (!hs->next_proto_neg_seen) { 1268 return 1; 1269 } 1270 1271 const uint8_t *npa; 1272 unsigned npa_len; 1273 1274 if (ssl->ctx->next_protos_advertised_cb( 1275 ssl, &npa, &npa_len, ssl->ctx->next_protos_advertised_cb_arg) != 1276 SSL_TLSEXT_ERR_OK) { 1277 hs->next_proto_neg_seen = 0; 1278 return 1; 1279 } 1280 1281 CBB contents; 1282 if (!CBB_add_u16(out, TLSEXT_TYPE_next_proto_neg) || 1283 !CBB_add_u16_length_prefixed(out, &contents) || 1284 !CBB_add_bytes(&contents, npa, npa_len) || 1285 !CBB_flush(out)) { 1286 return 0; 1287 } 1288 1289 return 1; 1290 } 1291 1292 1293 /* Signed certificate timestamps. 1294 * 1295 * https://tools.ietf.org/html/rfc6962#section-3.3.1 */ 1296 1297 static int ext_sct_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 1298 SSL *const ssl = hs->ssl; 1299 if (!ssl->signed_cert_timestamps_enabled) { 1300 return 1; 1301 } 1302 1303 if (!CBB_add_u16(out, TLSEXT_TYPE_certificate_timestamp) || 1304 !CBB_add_u16(out, 0 /* length */)) { 1305 return 0; 1306 } 1307 1308 return 1; 1309 } 1310 1311 static int ext_sct_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1312 CBS *contents) { 1313 SSL *const ssl = hs->ssl; 1314 if (contents == NULL) { 1315 return 1; 1316 } 1317 1318 /* TLS 1.3 SCTs are included in the Certificate extensions. */ 1319 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 1320 *out_alert = SSL_AD_DECODE_ERROR; 1321 return 0; 1322 } 1323 1324 /* If this is false then we should never have sent the SCT extension in the 1325 * ClientHello and thus this function should never have been called. */ 1326 assert(ssl->signed_cert_timestamps_enabled); 1327 1328 if (!ssl_is_sct_list_valid(contents)) { 1329 *out_alert = SSL_AD_DECODE_ERROR; 1330 return 0; 1331 } 1332 1333 /* Session resumption uses the original session information. The extension 1334 * should not be sent on resumption, but RFC 6962 did not make it a 1335 * requirement, so tolerate this. 1336 * 1337 * TODO(davidben): Enforce this anyway. */ 1338 if (!ssl->s3->session_reused && 1339 !CBS_stow(contents, &hs->new_session->tlsext_signed_cert_timestamp_list, 1340 &hs->new_session->tlsext_signed_cert_timestamp_list_length)) { 1341 *out_alert = SSL_AD_INTERNAL_ERROR; 1342 return 0; 1343 } 1344 1345 return 1; 1346 } 1347 1348 static int ext_sct_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1349 CBS *contents) { 1350 if (contents == NULL) { 1351 return 1; 1352 } 1353 1354 if (CBS_len(contents) != 0) { 1355 return 0; 1356 } 1357 1358 hs->scts_requested = 1; 1359 return 1; 1360 } 1361 1362 static int ext_sct_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 1363 SSL *const ssl = hs->ssl; 1364 /* The extension shouldn't be sent when resuming sessions. */ 1365 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION || 1366 ssl->s3->session_reused || 1367 ssl->cert->signed_cert_timestamp_list == NULL) { 1368 return 1; 1369 } 1370 1371 CBB contents; 1372 return CBB_add_u16(out, TLSEXT_TYPE_certificate_timestamp) && 1373 CBB_add_u16_length_prefixed(out, &contents) && 1374 CBB_add_bytes( 1375 &contents, 1376 CRYPTO_BUFFER_data(ssl->cert->signed_cert_timestamp_list), 1377 CRYPTO_BUFFER_len(ssl->cert->signed_cert_timestamp_list)) && 1378 CBB_flush(out); 1379 } 1380 1381 1382 /* Application-level Protocol Negotiation. 1383 * 1384 * https://tools.ietf.org/html/rfc7301 */ 1385 1386 static int ext_alpn_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 1387 SSL *const ssl = hs->ssl; 1388 if (ssl->alpn_client_proto_list == NULL || 1389 ssl->s3->initial_handshake_complete) { 1390 return 1; 1391 } 1392 1393 CBB contents, proto_list; 1394 if (!CBB_add_u16(out, TLSEXT_TYPE_application_layer_protocol_negotiation) || 1395 !CBB_add_u16_length_prefixed(out, &contents) || 1396 !CBB_add_u16_length_prefixed(&contents, &proto_list) || 1397 !CBB_add_bytes(&proto_list, ssl->alpn_client_proto_list, 1398 ssl->alpn_client_proto_list_len) || 1399 !CBB_flush(out)) { 1400 return 0; 1401 } 1402 1403 return 1; 1404 } 1405 1406 static int ext_alpn_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1407 CBS *contents) { 1408 SSL *const ssl = hs->ssl; 1409 if (contents == NULL) { 1410 return 1; 1411 } 1412 1413 assert(!ssl->s3->initial_handshake_complete); 1414 assert(ssl->alpn_client_proto_list != NULL); 1415 1416 if (hs->next_proto_neg_seen) { 1417 /* NPN and ALPN may not be negotiated in the same connection. */ 1418 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 1419 OPENSSL_PUT_ERROR(SSL, SSL_R_NEGOTIATED_BOTH_NPN_AND_ALPN); 1420 return 0; 1421 } 1422 1423 /* The extension data consists of a ProtocolNameList which must have 1424 * exactly one ProtocolName. Each of these is length-prefixed. */ 1425 CBS protocol_name_list, protocol_name; 1426 if (!CBS_get_u16_length_prefixed(contents, &protocol_name_list) || 1427 CBS_len(contents) != 0 || 1428 !CBS_get_u8_length_prefixed(&protocol_name_list, &protocol_name) || 1429 /* Empty protocol names are forbidden. */ 1430 CBS_len(&protocol_name) == 0 || 1431 CBS_len(&protocol_name_list) != 0) { 1432 return 0; 1433 } 1434 1435 /* Check that the protcol name is one of the ones we advertised. */ 1436 int protocol_ok = 0; 1437 CBS client_protocol_name_list, client_protocol_name; 1438 CBS_init(&client_protocol_name_list, ssl->alpn_client_proto_list, 1439 ssl->alpn_client_proto_list_len); 1440 while (CBS_len(&client_protocol_name_list) > 0) { 1441 if (!CBS_get_u8_length_prefixed(&client_protocol_name_list, 1442 &client_protocol_name)) { 1443 *out_alert = SSL_AD_INTERNAL_ERROR; 1444 return 0; 1445 } 1446 1447 if (CBS_len(&client_protocol_name) == CBS_len(&protocol_name) && 1448 OPENSSL_memcmp(CBS_data(&client_protocol_name), 1449 CBS_data(&protocol_name), 1450 CBS_len(&protocol_name)) == 0) { 1451 protocol_ok = 1; 1452 break; 1453 } 1454 } 1455 1456 if (!protocol_ok) { 1457 OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_ALPN_PROTOCOL); 1458 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 1459 return 0; 1460 } 1461 1462 if (!CBS_stow(&protocol_name, &ssl->s3->alpn_selected, 1463 &ssl->s3->alpn_selected_len)) { 1464 *out_alert = SSL_AD_INTERNAL_ERROR; 1465 return 0; 1466 } 1467 1468 return 1; 1469 } 1470 1471 int ssl_negotiate_alpn(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1472 const SSL_CLIENT_HELLO *client_hello) { 1473 SSL *const ssl = hs->ssl; 1474 CBS contents; 1475 if (ssl->ctx->alpn_select_cb == NULL || 1476 !ssl_client_hello_get_extension( 1477 client_hello, &contents, 1478 TLSEXT_TYPE_application_layer_protocol_negotiation)) { 1479 /* Ignore ALPN if not configured or no extension was supplied. */ 1480 return 1; 1481 } 1482 1483 /* ALPN takes precedence over NPN. */ 1484 hs->next_proto_neg_seen = 0; 1485 1486 CBS protocol_name_list; 1487 if (!CBS_get_u16_length_prefixed(&contents, &protocol_name_list) || 1488 CBS_len(&contents) != 0 || 1489 CBS_len(&protocol_name_list) < 2) { 1490 OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT); 1491 *out_alert = SSL_AD_DECODE_ERROR; 1492 return 0; 1493 } 1494 1495 /* Validate the protocol list. */ 1496 CBS protocol_name_list_copy = protocol_name_list; 1497 while (CBS_len(&protocol_name_list_copy) > 0) { 1498 CBS protocol_name; 1499 1500 if (!CBS_get_u8_length_prefixed(&protocol_name_list_copy, &protocol_name) || 1501 /* Empty protocol names are forbidden. */ 1502 CBS_len(&protocol_name) == 0) { 1503 OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT); 1504 *out_alert = SSL_AD_DECODE_ERROR; 1505 return 0; 1506 } 1507 } 1508 1509 const uint8_t *selected; 1510 uint8_t selected_len; 1511 if (ssl->ctx->alpn_select_cb( 1512 ssl, &selected, &selected_len, CBS_data(&protocol_name_list), 1513 CBS_len(&protocol_name_list), 1514 ssl->ctx->alpn_select_cb_arg) == SSL_TLSEXT_ERR_OK) { 1515 OPENSSL_free(ssl->s3->alpn_selected); 1516 ssl->s3->alpn_selected = BUF_memdup(selected, selected_len); 1517 if (ssl->s3->alpn_selected == NULL) { 1518 *out_alert = SSL_AD_INTERNAL_ERROR; 1519 return 0; 1520 } 1521 ssl->s3->alpn_selected_len = selected_len; 1522 } 1523 1524 return 1; 1525 } 1526 1527 static int ext_alpn_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 1528 SSL *const ssl = hs->ssl; 1529 if (ssl->s3->alpn_selected == NULL) { 1530 return 1; 1531 } 1532 1533 CBB contents, proto_list, proto; 1534 if (!CBB_add_u16(out, TLSEXT_TYPE_application_layer_protocol_negotiation) || 1535 !CBB_add_u16_length_prefixed(out, &contents) || 1536 !CBB_add_u16_length_prefixed(&contents, &proto_list) || 1537 !CBB_add_u8_length_prefixed(&proto_list, &proto) || 1538 !CBB_add_bytes(&proto, ssl->s3->alpn_selected, 1539 ssl->s3->alpn_selected_len) || 1540 !CBB_flush(out)) { 1541 return 0; 1542 } 1543 1544 return 1; 1545 } 1546 1547 1548 /* Channel ID. 1549 * 1550 * https://tools.ietf.org/html/draft-balfanz-tls-channelid-01 */ 1551 1552 static void ext_channel_id_init(SSL_HANDSHAKE *hs) { 1553 hs->ssl->s3->tlsext_channel_id_valid = 0; 1554 } 1555 1556 static int ext_channel_id_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 1557 SSL *const ssl = hs->ssl; 1558 if (!ssl->tlsext_channel_id_enabled || 1559 SSL_is_dtls(ssl)) { 1560 return 1; 1561 } 1562 1563 if (!CBB_add_u16(out, TLSEXT_TYPE_channel_id) || 1564 !CBB_add_u16(out, 0 /* length */)) { 1565 return 0; 1566 } 1567 1568 return 1; 1569 } 1570 1571 static int ext_channel_id_parse_serverhello(SSL_HANDSHAKE *hs, 1572 uint8_t *out_alert, CBS *contents) { 1573 SSL *const ssl = hs->ssl; 1574 if (contents == NULL) { 1575 return 1; 1576 } 1577 1578 assert(!SSL_is_dtls(ssl)); 1579 assert(ssl->tlsext_channel_id_enabled); 1580 1581 if (CBS_len(contents) != 0) { 1582 return 0; 1583 } 1584 1585 ssl->s3->tlsext_channel_id_valid = 1; 1586 return 1; 1587 } 1588 1589 static int ext_channel_id_parse_clienthello(SSL_HANDSHAKE *hs, 1590 uint8_t *out_alert, CBS *contents) { 1591 SSL *const ssl = hs->ssl; 1592 if (contents == NULL || 1593 !ssl->tlsext_channel_id_enabled || 1594 SSL_is_dtls(ssl)) { 1595 return 1; 1596 } 1597 1598 if (CBS_len(contents) != 0) { 1599 return 0; 1600 } 1601 1602 ssl->s3->tlsext_channel_id_valid = 1; 1603 return 1; 1604 } 1605 1606 static int ext_channel_id_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 1607 SSL *const ssl = hs->ssl; 1608 if (!ssl->s3->tlsext_channel_id_valid) { 1609 return 1; 1610 } 1611 1612 if (!CBB_add_u16(out, TLSEXT_TYPE_channel_id) || 1613 !CBB_add_u16(out, 0 /* length */)) { 1614 return 0; 1615 } 1616 1617 return 1; 1618 } 1619 1620 1621 /* Secure Real-time Transport Protocol (SRTP) extension. 1622 * 1623 * https://tools.ietf.org/html/rfc5764 */ 1624 1625 1626 static void ext_srtp_init(SSL_HANDSHAKE *hs) { 1627 hs->ssl->srtp_profile = NULL; 1628 } 1629 1630 static int ext_srtp_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 1631 SSL *const ssl = hs->ssl; 1632 STACK_OF(SRTP_PROTECTION_PROFILE) *profiles = SSL_get_srtp_profiles(ssl); 1633 if (profiles == NULL) { 1634 return 1; 1635 } 1636 const size_t num_profiles = sk_SRTP_PROTECTION_PROFILE_num(profiles); 1637 if (num_profiles == 0) { 1638 return 1; 1639 } 1640 1641 CBB contents, profile_ids; 1642 if (!CBB_add_u16(out, TLSEXT_TYPE_srtp) || 1643 !CBB_add_u16_length_prefixed(out, &contents) || 1644 !CBB_add_u16_length_prefixed(&contents, &profile_ids)) { 1645 return 0; 1646 } 1647 1648 for (size_t i = 0; i < num_profiles; i++) { 1649 if (!CBB_add_u16(&profile_ids, 1650 sk_SRTP_PROTECTION_PROFILE_value(profiles, i)->id)) { 1651 return 0; 1652 } 1653 } 1654 1655 if (!CBB_add_u8(&contents, 0 /* empty use_mki value */) || 1656 !CBB_flush(out)) { 1657 return 0; 1658 } 1659 1660 return 1; 1661 } 1662 1663 static int ext_srtp_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1664 CBS *contents) { 1665 SSL *const ssl = hs->ssl; 1666 if (contents == NULL) { 1667 return 1; 1668 } 1669 1670 /* The extension consists of a u16-prefixed profile ID list containing a 1671 * single uint16_t profile ID, then followed by a u8-prefixed srtp_mki field. 1672 * 1673 * See https://tools.ietf.org/html/rfc5764#section-4.1.1 */ 1674 CBS profile_ids, srtp_mki; 1675 uint16_t profile_id; 1676 if (!CBS_get_u16_length_prefixed(contents, &profile_ids) || 1677 !CBS_get_u16(&profile_ids, &profile_id) || 1678 CBS_len(&profile_ids) != 0 || 1679 !CBS_get_u8_length_prefixed(contents, &srtp_mki) || 1680 CBS_len(contents) != 0) { 1681 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST); 1682 return 0; 1683 } 1684 1685 if (CBS_len(&srtp_mki) != 0) { 1686 /* Must be no MKI, since we never offer one. */ 1687 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_MKI_VALUE); 1688 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 1689 return 0; 1690 } 1691 1692 STACK_OF(SRTP_PROTECTION_PROFILE) *profiles = SSL_get_srtp_profiles(ssl); 1693 1694 /* Check to see if the server gave us something we support (and presumably 1695 * offered). */ 1696 for (size_t i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(profiles); i++) { 1697 const SRTP_PROTECTION_PROFILE *profile = 1698 sk_SRTP_PROTECTION_PROFILE_value(profiles, i); 1699 1700 if (profile->id == profile_id) { 1701 ssl->srtp_profile = profile; 1702 return 1; 1703 } 1704 } 1705 1706 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST); 1707 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 1708 return 0; 1709 } 1710 1711 static int ext_srtp_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1712 CBS *contents) { 1713 SSL *const ssl = hs->ssl; 1714 if (contents == NULL) { 1715 return 1; 1716 } 1717 1718 CBS profile_ids, srtp_mki; 1719 if (!CBS_get_u16_length_prefixed(contents, &profile_ids) || 1720 CBS_len(&profile_ids) < 2 || 1721 !CBS_get_u8_length_prefixed(contents, &srtp_mki) || 1722 CBS_len(contents) != 0) { 1723 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST); 1724 return 0; 1725 } 1726 /* Discard the MKI value for now. */ 1727 1728 const STACK_OF(SRTP_PROTECTION_PROFILE) *server_profiles = 1729 SSL_get_srtp_profiles(ssl); 1730 1731 /* Pick the server's most preferred profile. */ 1732 for (size_t i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(server_profiles); i++) { 1733 const SRTP_PROTECTION_PROFILE *server_profile = 1734 sk_SRTP_PROTECTION_PROFILE_value(server_profiles, i); 1735 1736 CBS profile_ids_tmp; 1737 CBS_init(&profile_ids_tmp, CBS_data(&profile_ids), CBS_len(&profile_ids)); 1738 1739 while (CBS_len(&profile_ids_tmp) > 0) { 1740 uint16_t profile_id; 1741 if (!CBS_get_u16(&profile_ids_tmp, &profile_id)) { 1742 return 0; 1743 } 1744 1745 if (server_profile->id == profile_id) { 1746 ssl->srtp_profile = server_profile; 1747 return 1; 1748 } 1749 } 1750 } 1751 1752 return 1; 1753 } 1754 1755 static int ext_srtp_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 1756 SSL *const ssl = hs->ssl; 1757 if (ssl->srtp_profile == NULL) { 1758 return 1; 1759 } 1760 1761 CBB contents, profile_ids; 1762 if (!CBB_add_u16(out, TLSEXT_TYPE_srtp) || 1763 !CBB_add_u16_length_prefixed(out, &contents) || 1764 !CBB_add_u16_length_prefixed(&contents, &profile_ids) || 1765 !CBB_add_u16(&profile_ids, ssl->srtp_profile->id) || 1766 !CBB_add_u8(&contents, 0 /* empty MKI */) || 1767 !CBB_flush(out)) { 1768 return 0; 1769 } 1770 1771 return 1; 1772 } 1773 1774 1775 /* EC point formats. 1776 * 1777 * https://tools.ietf.org/html/rfc4492#section-5.1.2 */ 1778 1779 static int ext_ec_point_add_extension(SSL_HANDSHAKE *hs, CBB *out) { 1780 CBB contents, formats; 1781 if (!CBB_add_u16(out, TLSEXT_TYPE_ec_point_formats) || 1782 !CBB_add_u16_length_prefixed(out, &contents) || 1783 !CBB_add_u8_length_prefixed(&contents, &formats) || 1784 !CBB_add_u8(&formats, TLSEXT_ECPOINTFORMAT_uncompressed) || 1785 !CBB_flush(out)) { 1786 return 0; 1787 } 1788 1789 return 1; 1790 } 1791 1792 static int ext_ec_point_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 1793 uint16_t min_version, max_version; 1794 if (!ssl_get_version_range(hs->ssl, &min_version, &max_version)) { 1795 return 0; 1796 } 1797 1798 /* The point format extension is unneccessary in TLS 1.3. */ 1799 if (min_version >= TLS1_3_VERSION) { 1800 return 1; 1801 } 1802 1803 return ext_ec_point_add_extension(hs, out); 1804 } 1805 1806 static int ext_ec_point_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1807 CBS *contents) { 1808 if (contents == NULL) { 1809 return 1; 1810 } 1811 1812 if (ssl3_protocol_version(hs->ssl) >= TLS1_3_VERSION) { 1813 return 0; 1814 } 1815 1816 CBS ec_point_format_list; 1817 if (!CBS_get_u8_length_prefixed(contents, &ec_point_format_list) || 1818 CBS_len(contents) != 0) { 1819 return 0; 1820 } 1821 1822 /* Per RFC 4492, section 5.1.2, implementations MUST support the uncompressed 1823 * point format. */ 1824 if (OPENSSL_memchr(CBS_data(&ec_point_format_list), 1825 TLSEXT_ECPOINTFORMAT_uncompressed, 1826 CBS_len(&ec_point_format_list)) == NULL) { 1827 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 1828 return 0; 1829 } 1830 1831 return 1; 1832 } 1833 1834 static int ext_ec_point_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1835 CBS *contents) { 1836 if (ssl3_protocol_version(hs->ssl) >= TLS1_3_VERSION) { 1837 return 1; 1838 } 1839 1840 return ext_ec_point_parse_serverhello(hs, out_alert, contents); 1841 } 1842 1843 static int ext_ec_point_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 1844 SSL *const ssl = hs->ssl; 1845 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 1846 return 1; 1847 } 1848 1849 const uint32_t alg_k = hs->new_cipher->algorithm_mkey; 1850 const uint32_t alg_a = hs->new_cipher->algorithm_auth; 1851 const int using_ecc = (alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA); 1852 1853 if (!using_ecc) { 1854 return 1; 1855 } 1856 1857 return ext_ec_point_add_extension(hs, out); 1858 } 1859 1860 1861 /* Pre Shared Key 1862 * 1863 * https://tools.ietf.org/html/draft-ietf-tls-tls13-18#section-4.2.6 */ 1864 1865 static size_t ext_pre_shared_key_clienthello_length(SSL_HANDSHAKE *hs) { 1866 SSL *const ssl = hs->ssl; 1867 uint16_t min_version, max_version; 1868 if (!ssl_get_version_range(ssl, &min_version, &max_version)) { 1869 return 0; 1870 } 1871 1872 uint16_t session_version; 1873 if (max_version < TLS1_3_VERSION || ssl->session == NULL || 1874 !ssl->method->version_from_wire(&session_version, 1875 ssl->session->ssl_version) || 1876 session_version < TLS1_3_VERSION) { 1877 return 0; 1878 } 1879 1880 const EVP_MD *digest = SSL_SESSION_get_digest(ssl->session, ssl); 1881 if (digest == NULL) { 1882 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 1883 return 0; 1884 } 1885 1886 size_t binder_len = EVP_MD_size(digest); 1887 return 15 + ssl->session->tlsext_ticklen + binder_len; 1888 } 1889 1890 static int ext_pre_shared_key_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 1891 SSL *const ssl = hs->ssl; 1892 uint16_t min_version, max_version; 1893 if (!ssl_get_version_range(ssl, &min_version, &max_version)) { 1894 return 0; 1895 } 1896 1897 uint16_t session_version; 1898 if (max_version < TLS1_3_VERSION || ssl->session == NULL || 1899 !ssl->method->version_from_wire(&session_version, 1900 ssl->session->ssl_version) || 1901 session_version < TLS1_3_VERSION) { 1902 return 1; 1903 } 1904 1905 struct OPENSSL_timeval now; 1906 ssl_get_current_time(ssl, &now); 1907 uint32_t ticket_age = 1000 * (now.tv_sec - ssl->session->time); 1908 uint32_t obfuscated_ticket_age = ticket_age + ssl->session->ticket_age_add; 1909 1910 /* Fill in a placeholder zero binder of the appropriate length. It will be 1911 * computed and filled in later after length prefixes are computed. */ 1912 uint8_t zero_binder[EVP_MAX_MD_SIZE] = {0}; 1913 1914 const EVP_MD *digest = SSL_SESSION_get_digest(ssl->session, ssl); 1915 if (digest == NULL) { 1916 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 1917 return 0; 1918 } 1919 1920 size_t binder_len = EVP_MD_size(digest); 1921 1922 CBB contents, identity, ticket, binders, binder; 1923 if (!CBB_add_u16(out, TLSEXT_TYPE_pre_shared_key) || 1924 !CBB_add_u16_length_prefixed(out, &contents) || 1925 !CBB_add_u16_length_prefixed(&contents, &identity) || 1926 !CBB_add_u16_length_prefixed(&identity, &ticket) || 1927 !CBB_add_bytes(&ticket, ssl->session->tlsext_tick, 1928 ssl->session->tlsext_ticklen) || 1929 !CBB_add_u32(&identity, obfuscated_ticket_age) || 1930 !CBB_add_u16_length_prefixed(&contents, &binders) || 1931 !CBB_add_u8_length_prefixed(&binders, &binder) || 1932 !CBB_add_bytes(&binder, zero_binder, binder_len)) { 1933 return 0; 1934 } 1935 1936 hs->needs_psk_binder = 1; 1937 return CBB_flush(out); 1938 } 1939 1940 int ssl_ext_pre_shared_key_parse_serverhello(SSL_HANDSHAKE *hs, 1941 uint8_t *out_alert, 1942 CBS *contents) { 1943 uint16_t psk_id; 1944 if (!CBS_get_u16(contents, &psk_id) || 1945 CBS_len(contents) != 0) { 1946 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 1947 *out_alert = SSL_AD_DECODE_ERROR; 1948 return 0; 1949 } 1950 1951 /* We only advertise one PSK identity, so the only legal index is zero. */ 1952 if (psk_id != 0) { 1953 OPENSSL_PUT_ERROR(SSL, SSL_R_PSK_IDENTITY_NOT_FOUND); 1954 *out_alert = SSL_AD_UNKNOWN_PSK_IDENTITY; 1955 return 0; 1956 } 1957 1958 return 1; 1959 } 1960 1961 int ssl_ext_pre_shared_key_parse_clienthello( 1962 SSL_HANDSHAKE *hs, CBS *out_ticket, CBS *out_binders, 1963 uint32_t *out_obfuscated_ticket_age, uint8_t *out_alert, CBS *contents) { 1964 /* We only process the first PSK identity since we don't support pure PSK. */ 1965 CBS identities, binders; 1966 if (!CBS_get_u16_length_prefixed(contents, &identities) || 1967 !CBS_get_u16_length_prefixed(&identities, out_ticket) || 1968 !CBS_get_u32(&identities, out_obfuscated_ticket_age) || 1969 !CBS_get_u16_length_prefixed(contents, &binders) || 1970 CBS_len(&binders) == 0 || 1971 CBS_len(contents) != 0) { 1972 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 1973 *out_alert = SSL_AD_DECODE_ERROR; 1974 return 0; 1975 } 1976 1977 *out_binders = binders; 1978 1979 /* Check the syntax of the remaining identities, but do not process them. */ 1980 size_t num_identities = 1; 1981 while (CBS_len(&identities) != 0) { 1982 CBS unused_ticket; 1983 uint32_t unused_obfuscated_ticket_age; 1984 if (!CBS_get_u16_length_prefixed(&identities, &unused_ticket) || 1985 !CBS_get_u32(&identities, &unused_obfuscated_ticket_age)) { 1986 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 1987 *out_alert = SSL_AD_DECODE_ERROR; 1988 return 0; 1989 } 1990 1991 num_identities++; 1992 } 1993 1994 /* Check the syntax of the binders. The value will be checked later if 1995 * resuming. */ 1996 size_t num_binders = 0; 1997 while (CBS_len(&binders) != 0) { 1998 CBS binder; 1999 if (!CBS_get_u8_length_prefixed(&binders, &binder)) { 2000 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 2001 *out_alert = SSL_AD_DECODE_ERROR; 2002 return 0; 2003 } 2004 2005 num_binders++; 2006 } 2007 2008 if (num_identities != num_binders) { 2009 OPENSSL_PUT_ERROR(SSL, SSL_R_PSK_IDENTITY_BINDER_COUNT_MISMATCH); 2010 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 2011 return 0; 2012 } 2013 2014 return 1; 2015 } 2016 2017 int ssl_ext_pre_shared_key_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 2018 if (!hs->ssl->s3->session_reused) { 2019 return 1; 2020 } 2021 2022 CBB contents; 2023 if (!CBB_add_u16(out, TLSEXT_TYPE_pre_shared_key) || 2024 !CBB_add_u16_length_prefixed(out, &contents) || 2025 /* We only consider the first identity for resumption */ 2026 !CBB_add_u16(&contents, 0) || 2027 !CBB_flush(out)) { 2028 return 0; 2029 } 2030 2031 return 1; 2032 } 2033 2034 2035 /* Pre-Shared Key Exchange Modes 2036 * 2037 * https://tools.ietf.org/html/draft-ietf-tls-tls13-18#section-4.2.7 */ 2038 2039 static int ext_psk_key_exchange_modes_add_clienthello(SSL_HANDSHAKE *hs, 2040 CBB *out) { 2041 SSL *const ssl = hs->ssl; 2042 uint16_t min_version, max_version; 2043 if (!ssl_get_version_range(ssl, &min_version, &max_version)) { 2044 return 0; 2045 } 2046 2047 if (max_version < TLS1_3_VERSION) { 2048 return 1; 2049 } 2050 2051 CBB contents, ke_modes; 2052 if (!CBB_add_u16(out, TLSEXT_TYPE_psk_key_exchange_modes) || 2053 !CBB_add_u16_length_prefixed(out, &contents) || 2054 !CBB_add_u8_length_prefixed(&contents, &ke_modes) || 2055 !CBB_add_u8(&ke_modes, SSL_PSK_DHE_KE)) { 2056 return 0; 2057 } 2058 2059 return CBB_flush(out); 2060 } 2061 2062 static int ext_psk_key_exchange_modes_parse_clienthello(SSL_HANDSHAKE *hs, 2063 uint8_t *out_alert, 2064 CBS *contents) { 2065 if (contents == NULL) { 2066 return 1; 2067 } 2068 2069 CBS ke_modes; 2070 if (!CBS_get_u8_length_prefixed(contents, &ke_modes) || 2071 CBS_len(&ke_modes) == 0 || 2072 CBS_len(contents) != 0) { 2073 *out_alert = SSL_AD_DECODE_ERROR; 2074 return 0; 2075 } 2076 2077 /* We only support tickets with PSK_DHE_KE. */ 2078 hs->accept_psk_mode = OPENSSL_memchr(CBS_data(&ke_modes), SSL_PSK_DHE_KE, 2079 CBS_len(&ke_modes)) != NULL; 2080 2081 return 1; 2082 } 2083 2084 2085 /* Early Data Indication 2086 * 2087 * https://tools.ietf.org/html/draft-ietf-tls-tls13-18#section-4.2.8 */ 2088 2089 static int ext_early_data_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 2090 SSL *const ssl = hs->ssl; 2091 uint16_t session_version; 2092 if (ssl->session == NULL || 2093 !ssl->method->version_from_wire(&session_version, 2094 ssl->session->ssl_version) || 2095 session_version < TLS1_3_VERSION || 2096 ssl->session->ticket_max_early_data == 0 || 2097 hs->received_hello_retry_request || 2098 !ssl->ctx->enable_early_data) { 2099 return 1; 2100 } 2101 2102 hs->early_data_offered = 1; 2103 2104 if (!CBB_add_u16(out, TLSEXT_TYPE_early_data) || 2105 !CBB_add_u16(out, 0) || 2106 !CBB_flush(out)) { 2107 return 0; 2108 } 2109 2110 return 1; 2111 } 2112 2113 static int ext_early_data_parse_serverhello(SSL_HANDSHAKE *hs, 2114 uint8_t *out_alert, CBS *contents) { 2115 SSL *const ssl = hs->ssl; 2116 if (contents == NULL) { 2117 return 1; 2118 } 2119 2120 if (CBS_len(contents) != 0) { 2121 *out_alert = SSL_AD_DECODE_ERROR; 2122 return 0; 2123 } 2124 2125 if (!ssl->s3->session_reused) { 2126 *out_alert = SSL_AD_UNSUPPORTED_EXTENSION; 2127 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION); 2128 return 0; 2129 } 2130 2131 ssl->early_data_accepted = 1; 2132 return 1; 2133 } 2134 2135 static int ext_early_data_parse_clienthello(SSL_HANDSHAKE *hs, 2136 uint8_t *out_alert, CBS *contents) { 2137 SSL *const ssl = hs->ssl; 2138 if (contents == NULL || 2139 ssl3_protocol_version(ssl) < TLS1_3_VERSION) { 2140 return 1; 2141 } 2142 2143 if (CBS_len(contents) != 0) { 2144 *out_alert = SSL_AD_DECODE_ERROR; 2145 return 0; 2146 } 2147 2148 hs->early_data_offered = 1; 2149 return 1; 2150 } 2151 2152 static int ext_early_data_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 2153 if (!hs->ssl->early_data_accepted) { 2154 return 1; 2155 } 2156 2157 if (!CBB_add_u16(out, TLSEXT_TYPE_early_data) || 2158 !CBB_add_u16(out, 0) || 2159 !CBB_flush(out)) { 2160 return 0; 2161 } 2162 2163 return 1; 2164 } 2165 2166 2167 /* Key Share 2168 * 2169 * https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.5 */ 2170 2171 static int ext_key_share_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 2172 SSL *const ssl = hs->ssl; 2173 uint16_t min_version, max_version; 2174 if (!ssl_get_version_range(ssl, &min_version, &max_version)) { 2175 return 0; 2176 } 2177 2178 if (max_version < TLS1_3_VERSION) { 2179 return 1; 2180 } 2181 2182 CBB contents, kse_bytes; 2183 if (!CBB_add_u16(out, TLSEXT_TYPE_key_share) || 2184 !CBB_add_u16_length_prefixed(out, &contents) || 2185 !CBB_add_u16_length_prefixed(&contents, &kse_bytes)) { 2186 return 0; 2187 } 2188 2189 uint16_t group_id = hs->retry_group; 2190 if (hs->received_hello_retry_request) { 2191 /* We received a HelloRetryRequest without a new curve, so there is no new 2192 * share to append. Leave |ecdh_ctx| as-is. */ 2193 if (group_id == 0 && 2194 !CBB_add_bytes(&kse_bytes, hs->key_share_bytes, 2195 hs->key_share_bytes_len)) { 2196 return 0; 2197 } 2198 OPENSSL_free(hs->key_share_bytes); 2199 hs->key_share_bytes = NULL; 2200 hs->key_share_bytes_len = 0; 2201 if (group_id == 0) { 2202 return CBB_flush(out); 2203 } 2204 } else { 2205 /* Add a fake group. See draft-davidben-tls-grease-01. */ 2206 if (ssl->ctx->grease_enabled && 2207 (!CBB_add_u16(&kse_bytes, 2208 ssl_get_grease_value(ssl, ssl_grease_group)) || 2209 !CBB_add_u16(&kse_bytes, 1 /* length */) || 2210 !CBB_add_u8(&kse_bytes, 0 /* one byte key share */))) { 2211 return 0; 2212 } 2213 2214 /* Predict the most preferred group. */ 2215 const uint16_t *groups; 2216 size_t groups_len; 2217 tls1_get_grouplist(ssl, &groups, &groups_len); 2218 if (groups_len == 0) { 2219 OPENSSL_PUT_ERROR(SSL, SSL_R_NO_GROUPS_SPECIFIED); 2220 return 0; 2221 } 2222 2223 group_id = groups[0]; 2224 } 2225 2226 CBB key_exchange; 2227 if (!CBB_add_u16(&kse_bytes, group_id) || 2228 !CBB_add_u16_length_prefixed(&kse_bytes, &key_exchange) || 2229 !SSL_ECDH_CTX_init(&hs->ecdh_ctx, group_id) || 2230 !SSL_ECDH_CTX_offer(&hs->ecdh_ctx, &key_exchange) || 2231 !CBB_flush(&kse_bytes)) { 2232 return 0; 2233 } 2234 2235 if (!hs->received_hello_retry_request) { 2236 /* Save the contents of the extension to repeat it in the second 2237 * ClientHello. */ 2238 hs->key_share_bytes_len = CBB_len(&kse_bytes); 2239 hs->key_share_bytes = BUF_memdup(CBB_data(&kse_bytes), CBB_len(&kse_bytes)); 2240 if (hs->key_share_bytes == NULL) { 2241 return 0; 2242 } 2243 } 2244 2245 return CBB_flush(out); 2246 } 2247 2248 int ssl_ext_key_share_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t **out_secret, 2249 size_t *out_secret_len, 2250 uint8_t *out_alert, CBS *contents) { 2251 CBS peer_key; 2252 uint16_t group_id; 2253 if (!CBS_get_u16(contents, &group_id) || 2254 !CBS_get_u16_length_prefixed(contents, &peer_key) || 2255 CBS_len(contents) != 0) { 2256 *out_alert = SSL_AD_DECODE_ERROR; 2257 return 0; 2258 } 2259 2260 if (SSL_ECDH_CTX_get_id(&hs->ecdh_ctx) != group_id) { 2261 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 2262 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CURVE); 2263 return 0; 2264 } 2265 2266 if (!SSL_ECDH_CTX_finish(&hs->ecdh_ctx, out_secret, out_secret_len, out_alert, 2267 CBS_data(&peer_key), CBS_len(&peer_key))) { 2268 *out_alert = SSL_AD_INTERNAL_ERROR; 2269 return 0; 2270 } 2271 2272 hs->new_session->group_id = group_id; 2273 SSL_ECDH_CTX_cleanup(&hs->ecdh_ctx); 2274 return 1; 2275 } 2276 2277 int ssl_ext_key_share_parse_clienthello(SSL_HANDSHAKE *hs, int *out_found, 2278 uint8_t **out_secret, 2279 size_t *out_secret_len, 2280 uint8_t *out_alert, CBS *contents) { 2281 uint16_t group_id; 2282 CBS key_shares; 2283 if (!tls1_get_shared_group(hs, &group_id)) { 2284 OPENSSL_PUT_ERROR(SSL, SSL_R_NO_SHARED_GROUP); 2285 *out_alert = SSL_AD_HANDSHAKE_FAILURE; 2286 return 0; 2287 } 2288 2289 if (!CBS_get_u16_length_prefixed(contents, &key_shares) || 2290 CBS_len(contents) != 0) { 2291 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 2292 return 0; 2293 } 2294 2295 /* Find the corresponding key share. */ 2296 int found = 0; 2297 CBS peer_key; 2298 while (CBS_len(&key_shares) > 0) { 2299 uint16_t id; 2300 CBS peer_key_tmp; 2301 if (!CBS_get_u16(&key_shares, &id) || 2302 !CBS_get_u16_length_prefixed(&key_shares, &peer_key_tmp)) { 2303 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 2304 return 0; 2305 } 2306 2307 if (id == group_id) { 2308 if (found) { 2309 OPENSSL_PUT_ERROR(SSL, SSL_R_DUPLICATE_KEY_SHARE); 2310 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 2311 return 0; 2312 } 2313 2314 found = 1; 2315 peer_key = peer_key_tmp; 2316 /* Continue parsing the structure to keep peers honest. */ 2317 } 2318 } 2319 2320 if (!found) { 2321 *out_found = 0; 2322 *out_secret = NULL; 2323 *out_secret_len = 0; 2324 return 1; 2325 } 2326 2327 /* Compute the DH secret. */ 2328 uint8_t *secret = NULL; 2329 size_t secret_len; 2330 SSL_ECDH_CTX group; 2331 OPENSSL_memset(&group, 0, sizeof(SSL_ECDH_CTX)); 2332 CBB public_key; 2333 if (!CBB_init(&public_key, 32) || 2334 !SSL_ECDH_CTX_init(&group, group_id) || 2335 !SSL_ECDH_CTX_accept(&group, &public_key, &secret, &secret_len, out_alert, 2336 CBS_data(&peer_key), CBS_len(&peer_key)) || 2337 !CBB_finish(&public_key, &hs->public_key, &hs->public_key_len)) { 2338 OPENSSL_free(secret); 2339 SSL_ECDH_CTX_cleanup(&group); 2340 CBB_cleanup(&public_key); 2341 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 2342 return 0; 2343 } 2344 2345 SSL_ECDH_CTX_cleanup(&group); 2346 2347 *out_secret = secret; 2348 *out_secret_len = secret_len; 2349 *out_found = 1; 2350 return 1; 2351 } 2352 2353 int ssl_ext_key_share_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 2354 uint16_t group_id; 2355 CBB kse_bytes, public_key; 2356 if (!tls1_get_shared_group(hs, &group_id) || 2357 !CBB_add_u16(out, TLSEXT_TYPE_key_share) || 2358 !CBB_add_u16_length_prefixed(out, &kse_bytes) || 2359 !CBB_add_u16(&kse_bytes, group_id) || 2360 !CBB_add_u16_length_prefixed(&kse_bytes, &public_key) || 2361 !CBB_add_bytes(&public_key, hs->public_key, hs->public_key_len) || 2362 !CBB_flush(out)) { 2363 return 0; 2364 } 2365 2366 OPENSSL_free(hs->public_key); 2367 hs->public_key = NULL; 2368 hs->public_key_len = 0; 2369 2370 hs->new_session->group_id = group_id; 2371 return 1; 2372 } 2373 2374 2375 /* Supported Versions 2376 * 2377 * https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.1 */ 2378 2379 static int ext_supported_versions_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 2380 SSL *const ssl = hs->ssl; 2381 uint16_t min_version, max_version; 2382 if (!ssl_get_version_range(ssl, &min_version, &max_version)) { 2383 return 0; 2384 } 2385 2386 if (max_version <= TLS1_2_VERSION) { 2387 return 1; 2388 } 2389 2390 CBB contents, versions; 2391 if (!CBB_add_u16(out, TLSEXT_TYPE_supported_versions) || 2392 !CBB_add_u16_length_prefixed(out, &contents) || 2393 !CBB_add_u8_length_prefixed(&contents, &versions)) { 2394 return 0; 2395 } 2396 2397 /* Add a fake version. See draft-davidben-tls-grease-01. */ 2398 if (ssl->ctx->grease_enabled && 2399 !CBB_add_u16(&versions, ssl_get_grease_value(ssl, ssl_grease_version))) { 2400 return 0; 2401 } 2402 2403 for (uint16_t version = max_version; version >= min_version; version--) { 2404 if (!CBB_add_u16(&versions, ssl->method->version_to_wire(version))) { 2405 return 0; 2406 } 2407 } 2408 2409 if (!CBB_flush(out)) { 2410 return 0; 2411 } 2412 2413 return 1; 2414 } 2415 2416 2417 /* Cookie 2418 * 2419 * https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.2 */ 2420 2421 static int ext_cookie_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 2422 if (hs->cookie == NULL) { 2423 return 1; 2424 } 2425 2426 CBB contents, cookie; 2427 if (!CBB_add_u16(out, TLSEXT_TYPE_cookie) || 2428 !CBB_add_u16_length_prefixed(out, &contents) || 2429 !CBB_add_u16_length_prefixed(&contents, &cookie) || 2430 !CBB_add_bytes(&cookie, hs->cookie, hs->cookie_len) || 2431 !CBB_flush(out)) { 2432 return 0; 2433 } 2434 2435 /* The cookie is no longer needed in memory. */ 2436 OPENSSL_free(hs->cookie); 2437 hs->cookie = NULL; 2438 hs->cookie_len = 0; 2439 return 1; 2440 } 2441 2442 2443 /* Negotiated Groups 2444 * 2445 * https://tools.ietf.org/html/rfc4492#section-5.1.2 2446 * https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.4 */ 2447 2448 static int ext_supported_groups_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 2449 SSL *const ssl = hs->ssl; 2450 CBB contents, groups_bytes; 2451 if (!CBB_add_u16(out, TLSEXT_TYPE_supported_groups) || 2452 !CBB_add_u16_length_prefixed(out, &contents) || 2453 !CBB_add_u16_length_prefixed(&contents, &groups_bytes)) { 2454 return 0; 2455 } 2456 2457 /* Add a fake group. See draft-davidben-tls-grease-01. */ 2458 if (ssl->ctx->grease_enabled && 2459 !CBB_add_u16(&groups_bytes, 2460 ssl_get_grease_value(ssl, ssl_grease_group))) { 2461 return 0; 2462 } 2463 2464 const uint16_t *groups; 2465 size_t groups_len; 2466 tls1_get_grouplist(ssl, &groups, &groups_len); 2467 2468 for (size_t i = 0; i < groups_len; i++) { 2469 if (!CBB_add_u16(&groups_bytes, groups[i])) { 2470 return 0; 2471 } 2472 } 2473 2474 return CBB_flush(out); 2475 } 2476 2477 static int ext_supported_groups_parse_serverhello(SSL_HANDSHAKE *hs, 2478 uint8_t *out_alert, 2479 CBS *contents) { 2480 /* This extension is not expected to be echoed by servers in TLS 1.2, but some 2481 * BigIP servers send it nonetheless, so do not enforce this. */ 2482 return 1; 2483 } 2484 2485 static int ext_supported_groups_parse_clienthello(SSL_HANDSHAKE *hs, 2486 uint8_t *out_alert, 2487 CBS *contents) { 2488 if (contents == NULL) { 2489 return 1; 2490 } 2491 2492 CBS supported_group_list; 2493 if (!CBS_get_u16_length_prefixed(contents, &supported_group_list) || 2494 CBS_len(&supported_group_list) == 0 || 2495 (CBS_len(&supported_group_list) & 1) != 0 || 2496 CBS_len(contents) != 0) { 2497 return 0; 2498 } 2499 2500 hs->peer_supported_group_list = 2501 OPENSSL_malloc(CBS_len(&supported_group_list)); 2502 if (hs->peer_supported_group_list == NULL) { 2503 *out_alert = SSL_AD_INTERNAL_ERROR; 2504 return 0; 2505 } 2506 2507 const size_t num_groups = CBS_len(&supported_group_list) / 2; 2508 for (size_t i = 0; i < num_groups; i++) { 2509 if (!CBS_get_u16(&supported_group_list, 2510 &hs->peer_supported_group_list[i])) { 2511 goto err; 2512 } 2513 } 2514 2515 assert(CBS_len(&supported_group_list) == 0); 2516 hs->peer_supported_group_list_len = num_groups; 2517 2518 return 1; 2519 2520 err: 2521 OPENSSL_free(hs->peer_supported_group_list); 2522 hs->peer_supported_group_list = NULL; 2523 *out_alert = SSL_AD_INTERNAL_ERROR; 2524 return 0; 2525 } 2526 2527 static int ext_supported_groups_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 2528 /* Servers don't echo this extension. */ 2529 return 1; 2530 } 2531 2532 2533 /* kExtensions contains all the supported extensions. */ 2534 static const struct tls_extension kExtensions[] = { 2535 { 2536 TLSEXT_TYPE_renegotiate, 2537 NULL, 2538 ext_ri_add_clienthello, 2539 ext_ri_parse_serverhello, 2540 ext_ri_parse_clienthello, 2541 ext_ri_add_serverhello, 2542 }, 2543 { 2544 TLSEXT_TYPE_server_name, 2545 NULL, 2546 ext_sni_add_clienthello, 2547 ext_sni_parse_serverhello, 2548 ext_sni_parse_clienthello, 2549 ext_sni_add_serverhello, 2550 }, 2551 { 2552 TLSEXT_TYPE_extended_master_secret, 2553 NULL, 2554 ext_ems_add_clienthello, 2555 ext_ems_parse_serverhello, 2556 ext_ems_parse_clienthello, 2557 ext_ems_add_serverhello, 2558 }, 2559 { 2560 TLSEXT_TYPE_session_ticket, 2561 NULL, 2562 ext_ticket_add_clienthello, 2563 ext_ticket_parse_serverhello, 2564 /* Ticket extension client parsing is handled in ssl_session.c */ 2565 ignore_parse_clienthello, 2566 ext_ticket_add_serverhello, 2567 }, 2568 { 2569 TLSEXT_TYPE_signature_algorithms, 2570 NULL, 2571 ext_sigalgs_add_clienthello, 2572 forbid_parse_serverhello, 2573 ext_sigalgs_parse_clienthello, 2574 dont_add_serverhello, 2575 }, 2576 { 2577 TLSEXT_TYPE_status_request, 2578 NULL, 2579 ext_ocsp_add_clienthello, 2580 ext_ocsp_parse_serverhello, 2581 ext_ocsp_parse_clienthello, 2582 ext_ocsp_add_serverhello, 2583 }, 2584 { 2585 TLSEXT_TYPE_next_proto_neg, 2586 NULL, 2587 ext_npn_add_clienthello, 2588 ext_npn_parse_serverhello, 2589 ext_npn_parse_clienthello, 2590 ext_npn_add_serverhello, 2591 }, 2592 { 2593 TLSEXT_TYPE_certificate_timestamp, 2594 NULL, 2595 ext_sct_add_clienthello, 2596 ext_sct_parse_serverhello, 2597 ext_sct_parse_clienthello, 2598 ext_sct_add_serverhello, 2599 }, 2600 { 2601 TLSEXT_TYPE_application_layer_protocol_negotiation, 2602 NULL, 2603 ext_alpn_add_clienthello, 2604 ext_alpn_parse_serverhello, 2605 /* ALPN is negotiated late in |ssl_negotiate_alpn|. */ 2606 ignore_parse_clienthello, 2607 ext_alpn_add_serverhello, 2608 }, 2609 { 2610 TLSEXT_TYPE_channel_id, 2611 ext_channel_id_init, 2612 ext_channel_id_add_clienthello, 2613 ext_channel_id_parse_serverhello, 2614 ext_channel_id_parse_clienthello, 2615 ext_channel_id_add_serverhello, 2616 }, 2617 { 2618 TLSEXT_TYPE_srtp, 2619 ext_srtp_init, 2620 ext_srtp_add_clienthello, 2621 ext_srtp_parse_serverhello, 2622 ext_srtp_parse_clienthello, 2623 ext_srtp_add_serverhello, 2624 }, 2625 { 2626 TLSEXT_TYPE_ec_point_formats, 2627 NULL, 2628 ext_ec_point_add_clienthello, 2629 ext_ec_point_parse_serverhello, 2630 ext_ec_point_parse_clienthello, 2631 ext_ec_point_add_serverhello, 2632 }, 2633 { 2634 TLSEXT_TYPE_key_share, 2635 NULL, 2636 ext_key_share_add_clienthello, 2637 forbid_parse_serverhello, 2638 ignore_parse_clienthello, 2639 dont_add_serverhello, 2640 }, 2641 { 2642 TLSEXT_TYPE_psk_key_exchange_modes, 2643 NULL, 2644 ext_psk_key_exchange_modes_add_clienthello, 2645 forbid_parse_serverhello, 2646 ext_psk_key_exchange_modes_parse_clienthello, 2647 dont_add_serverhello, 2648 }, 2649 { 2650 TLSEXT_TYPE_early_data, 2651 NULL, 2652 ext_early_data_add_clienthello, 2653 ext_early_data_parse_serverhello, 2654 ext_early_data_parse_clienthello, 2655 ext_early_data_add_serverhello, 2656 }, 2657 { 2658 TLSEXT_TYPE_supported_versions, 2659 NULL, 2660 ext_supported_versions_add_clienthello, 2661 forbid_parse_serverhello, 2662 ignore_parse_clienthello, 2663 dont_add_serverhello, 2664 }, 2665 { 2666 TLSEXT_TYPE_cookie, 2667 NULL, 2668 ext_cookie_add_clienthello, 2669 forbid_parse_serverhello, 2670 ignore_parse_clienthello, 2671 dont_add_serverhello, 2672 }, 2673 /* The final extension must be non-empty. WebSphere Application Server 7.0 is 2674 * intolerant to the last extension being zero-length. See 2675 * https://crbug.com/363583. */ 2676 { 2677 TLSEXT_TYPE_supported_groups, 2678 NULL, 2679 ext_supported_groups_add_clienthello, 2680 ext_supported_groups_parse_serverhello, 2681 ext_supported_groups_parse_clienthello, 2682 ext_supported_groups_add_serverhello, 2683 }, 2684 }; 2685 2686 #define kNumExtensions (sizeof(kExtensions) / sizeof(struct tls_extension)) 2687 2688 OPENSSL_COMPILE_ASSERT(kNumExtensions <= 2689 sizeof(((SSL_HANDSHAKE *)NULL)->extensions.sent) * 8, 2690 too_many_extensions_for_sent_bitset); 2691 OPENSSL_COMPILE_ASSERT( 2692 kNumExtensions <= sizeof(((SSL_HANDSHAKE *)NULL)->extensions.received) * 8, 2693 too_many_extensions_for_received_bitset); 2694 2695 static const struct tls_extension *tls_extension_find(uint32_t *out_index, 2696 uint16_t value) { 2697 unsigned i; 2698 for (i = 0; i < kNumExtensions; i++) { 2699 if (kExtensions[i].value == value) { 2700 *out_index = i; 2701 return &kExtensions[i]; 2702 } 2703 } 2704 2705 return NULL; 2706 } 2707 2708 int SSL_extension_supported(unsigned extension_value) { 2709 uint32_t index; 2710 return extension_value == TLSEXT_TYPE_padding || 2711 tls_extension_find(&index, extension_value) != NULL; 2712 } 2713 2714 int ssl_add_clienthello_tlsext(SSL_HANDSHAKE *hs, CBB *out, size_t header_len) { 2715 SSL *const ssl = hs->ssl; 2716 /* Don't add extensions for SSLv3 unless doing secure renegotiation. */ 2717 if (hs->client_version == SSL3_VERSION && 2718 !ssl->s3->send_connection_binding) { 2719 return 1; 2720 } 2721 2722 CBB extensions; 2723 if (!CBB_add_u16_length_prefixed(out, &extensions)) { 2724 goto err; 2725 } 2726 2727 hs->extensions.sent = 0; 2728 hs->custom_extensions.sent = 0; 2729 2730 for (size_t i = 0; i < kNumExtensions; i++) { 2731 if (kExtensions[i].init != NULL) { 2732 kExtensions[i].init(hs); 2733 } 2734 } 2735 2736 uint16_t grease_ext1 = 0; 2737 if (ssl->ctx->grease_enabled) { 2738 /* Add a fake empty extension. See draft-davidben-tls-grease-01. */ 2739 grease_ext1 = ssl_get_grease_value(ssl, ssl_grease_extension1); 2740 if (!CBB_add_u16(&extensions, grease_ext1) || 2741 !CBB_add_u16(&extensions, 0 /* zero length */)) { 2742 goto err; 2743 } 2744 } 2745 2746 for (size_t i = 0; i < kNumExtensions; i++) { 2747 const size_t len_before = CBB_len(&extensions); 2748 if (!kExtensions[i].add_clienthello(hs, &extensions)) { 2749 OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_ADDING_EXTENSION); 2750 ERR_add_error_dataf("extension %u", (unsigned)kExtensions[i].value); 2751 goto err; 2752 } 2753 2754 if (CBB_len(&extensions) != len_before) { 2755 hs->extensions.sent |= (1u << i); 2756 } 2757 } 2758 2759 if (!custom_ext_add_clienthello(hs, &extensions)) { 2760 goto err; 2761 } 2762 2763 if (ssl->ctx->grease_enabled) { 2764 /* Add a fake non-empty extension. See draft-davidben-tls-grease-01. */ 2765 uint16_t grease_ext2 = ssl_get_grease_value(ssl, ssl_grease_extension2); 2766 2767 /* The two fake extensions must not have the same value. GREASE values are 2768 * of the form 0x1a1a, 0x2a2a, 0x3a3a, etc., so XOR to generate a different 2769 * one. */ 2770 if (grease_ext1 == grease_ext2) { 2771 grease_ext2 ^= 0x1010; 2772 } 2773 2774 if (!CBB_add_u16(&extensions, grease_ext2) || 2775 !CBB_add_u16(&extensions, 1 /* one byte length */) || 2776 !CBB_add_u8(&extensions, 0 /* single zero byte as contents */)) { 2777 goto err; 2778 } 2779 } 2780 2781 if (!SSL_is_dtls(ssl)) { 2782 size_t psk_extension_len = ext_pre_shared_key_clienthello_length(hs); 2783 header_len += 2 + CBB_len(&extensions) + psk_extension_len; 2784 if (header_len > 0xff && header_len < 0x200) { 2785 /* Add padding to workaround bugs in F5 terminators. See RFC 7685. 2786 * 2787 * NB: because this code works out the length of all existing extensions 2788 * it MUST always appear last. */ 2789 size_t padding_len = 0x200 - header_len; 2790 /* Extensions take at least four bytes to encode. Always include at least 2791 * one byte of data if including the extension. WebSphere Application 2792 * Server 7.0 is intolerant to the last extension being zero-length. See 2793 * https://crbug.com/363583. */ 2794 if (padding_len >= 4 + 1) { 2795 padding_len -= 4; 2796 } else { 2797 padding_len = 1; 2798 } 2799 2800 uint8_t *padding_bytes; 2801 if (!CBB_add_u16(&extensions, TLSEXT_TYPE_padding) || 2802 !CBB_add_u16(&extensions, padding_len) || 2803 !CBB_add_space(&extensions, &padding_bytes, padding_len)) { 2804 goto err; 2805 } 2806 2807 OPENSSL_memset(padding_bytes, 0, padding_len); 2808 } 2809 } 2810 2811 /* The PSK extension must be last, including after the padding. */ 2812 if (!ext_pre_shared_key_add_clienthello(hs, &extensions)) { 2813 goto err; 2814 } 2815 2816 /* Discard empty extensions blocks. */ 2817 if (CBB_len(&extensions) == 0) { 2818 CBB_discard_child(out); 2819 } 2820 2821 return CBB_flush(out); 2822 2823 err: 2824 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 2825 return 0; 2826 } 2827 2828 int ssl_add_serverhello_tlsext(SSL_HANDSHAKE *hs, CBB *out) { 2829 SSL *const ssl = hs->ssl; 2830 CBB extensions; 2831 if (!CBB_add_u16_length_prefixed(out, &extensions)) { 2832 goto err; 2833 } 2834 2835 for (unsigned i = 0; i < kNumExtensions; i++) { 2836 if (!(hs->extensions.received & (1u << i))) { 2837 /* Don't send extensions that were not received. */ 2838 continue; 2839 } 2840 2841 if (!kExtensions[i].add_serverhello(hs, &extensions)) { 2842 OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_ADDING_EXTENSION); 2843 ERR_add_error_dataf("extension %u", (unsigned)kExtensions[i].value); 2844 goto err; 2845 } 2846 } 2847 2848 if (!custom_ext_add_serverhello(hs, &extensions)) { 2849 goto err; 2850 } 2851 2852 /* Discard empty extensions blocks before TLS 1.3. */ 2853 if (ssl3_protocol_version(ssl) < TLS1_3_VERSION && 2854 CBB_len(&extensions) == 0) { 2855 CBB_discard_child(out); 2856 } 2857 2858 return CBB_flush(out); 2859 2860 err: 2861 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 2862 return 0; 2863 } 2864 2865 static int ssl_scan_clienthello_tlsext(SSL_HANDSHAKE *hs, 2866 const SSL_CLIENT_HELLO *client_hello, 2867 int *out_alert) { 2868 SSL *const ssl = hs->ssl; 2869 for (size_t i = 0; i < kNumExtensions; i++) { 2870 if (kExtensions[i].init != NULL) { 2871 kExtensions[i].init(hs); 2872 } 2873 } 2874 2875 hs->extensions.received = 0; 2876 hs->custom_extensions.received = 0; 2877 2878 CBS extensions; 2879 CBS_init(&extensions, client_hello->extensions, client_hello->extensions_len); 2880 while (CBS_len(&extensions) != 0) { 2881 uint16_t type; 2882 CBS extension; 2883 2884 /* Decode the next extension. */ 2885 if (!CBS_get_u16(&extensions, &type) || 2886 !CBS_get_u16_length_prefixed(&extensions, &extension)) { 2887 *out_alert = SSL_AD_DECODE_ERROR; 2888 return 0; 2889 } 2890 2891 /* RFC 5746 made the existence of extensions in SSL 3.0 somewhat 2892 * ambiguous. Ignore all but the renegotiation_info extension. */ 2893 if (ssl->version == SSL3_VERSION && type != TLSEXT_TYPE_renegotiate) { 2894 continue; 2895 } 2896 2897 unsigned ext_index; 2898 const struct tls_extension *const ext = 2899 tls_extension_find(&ext_index, type); 2900 2901 if (ext == NULL) { 2902 if (!custom_ext_parse_clienthello(hs, out_alert, type, &extension)) { 2903 OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_PARSING_EXTENSION); 2904 return 0; 2905 } 2906 continue; 2907 } 2908 2909 hs->extensions.received |= (1u << ext_index); 2910 uint8_t alert = SSL_AD_DECODE_ERROR; 2911 if (!ext->parse_clienthello(hs, &alert, &extension)) { 2912 *out_alert = alert; 2913 OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_PARSING_EXTENSION); 2914 ERR_add_error_dataf("extension %u", (unsigned)type); 2915 return 0; 2916 } 2917 } 2918 2919 for (size_t i = 0; i < kNumExtensions; i++) { 2920 if (hs->extensions.received & (1u << i)) { 2921 continue; 2922 } 2923 2924 CBS *contents = NULL, fake_contents; 2925 static const uint8_t kFakeRenegotiateExtension[] = {0}; 2926 if (kExtensions[i].value == TLSEXT_TYPE_renegotiate && 2927 ssl_client_cipher_list_contains_cipher(client_hello, 2928 SSL3_CK_SCSV & 0xffff)) { 2929 /* The renegotiation SCSV was received so pretend that we received a 2930 * renegotiation extension. */ 2931 CBS_init(&fake_contents, kFakeRenegotiateExtension, 2932 sizeof(kFakeRenegotiateExtension)); 2933 contents = &fake_contents; 2934 hs->extensions.received |= (1u << i); 2935 } 2936 2937 /* Extension wasn't observed so call the callback with a NULL 2938 * parameter. */ 2939 uint8_t alert = SSL_AD_DECODE_ERROR; 2940 if (!kExtensions[i].parse_clienthello(hs, &alert, contents)) { 2941 OPENSSL_PUT_ERROR(SSL, SSL_R_MISSING_EXTENSION); 2942 ERR_add_error_dataf("extension %u", (unsigned)kExtensions[i].value); 2943 *out_alert = alert; 2944 return 0; 2945 } 2946 } 2947 2948 return 1; 2949 } 2950 2951 int ssl_parse_clienthello_tlsext(SSL_HANDSHAKE *hs, 2952 const SSL_CLIENT_HELLO *client_hello) { 2953 SSL *const ssl = hs->ssl; 2954 int alert = SSL_AD_DECODE_ERROR; 2955 if (ssl_scan_clienthello_tlsext(hs, client_hello, &alert) <= 0) { 2956 ssl3_send_alert(ssl, SSL3_AL_FATAL, alert); 2957 return 0; 2958 } 2959 2960 if (ssl_check_clienthello_tlsext(hs) <= 0) { 2961 OPENSSL_PUT_ERROR(SSL, SSL_R_CLIENTHELLO_TLSEXT); 2962 return 0; 2963 } 2964 2965 return 1; 2966 } 2967 2968 static int ssl_scan_serverhello_tlsext(SSL_HANDSHAKE *hs, CBS *cbs, 2969 int *out_alert) { 2970 SSL *const ssl = hs->ssl; 2971 /* Before TLS 1.3, ServerHello extensions blocks may be omitted if empty. */ 2972 if (CBS_len(cbs) == 0 && ssl3_protocol_version(ssl) < TLS1_3_VERSION) { 2973 return 1; 2974 } 2975 2976 /* Decode the extensions block and check it is valid. */ 2977 CBS extensions; 2978 if (!CBS_get_u16_length_prefixed(cbs, &extensions) || 2979 !tls1_check_duplicate_extensions(&extensions)) { 2980 *out_alert = SSL_AD_DECODE_ERROR; 2981 return 0; 2982 } 2983 2984 uint32_t received = 0; 2985 while (CBS_len(&extensions) != 0) { 2986 uint16_t type; 2987 CBS extension; 2988 2989 /* Decode the next extension. */ 2990 if (!CBS_get_u16(&extensions, &type) || 2991 !CBS_get_u16_length_prefixed(&extensions, &extension)) { 2992 *out_alert = SSL_AD_DECODE_ERROR; 2993 return 0; 2994 } 2995 2996 unsigned ext_index; 2997 const struct tls_extension *const ext = 2998 tls_extension_find(&ext_index, type); 2999 3000 if (ext == NULL) { 3001 if (!custom_ext_parse_serverhello(hs, out_alert, type, &extension)) { 3002 return 0; 3003 } 3004 continue; 3005 } 3006 3007 OPENSSL_COMPILE_ASSERT(kNumExtensions <= sizeof(hs->extensions.sent) * 8, 3008 too_many_bits); 3009 3010 if (!(hs->extensions.sent & (1u << ext_index)) && 3011 type != TLSEXT_TYPE_renegotiate) { 3012 /* If the extension was never sent then it is illegal, except for the 3013 * renegotiation extension which, in SSL 3.0, is signaled via SCSV. */ 3014 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION); 3015 ERR_add_error_dataf("extension :%u", (unsigned)type); 3016 *out_alert = SSL_AD_UNSUPPORTED_EXTENSION; 3017 return 0; 3018 } 3019 3020 received |= (1u << ext_index); 3021 3022 uint8_t alert = SSL_AD_DECODE_ERROR; 3023 if (!ext->parse_serverhello(hs, &alert, &extension)) { 3024 OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_PARSING_EXTENSION); 3025 ERR_add_error_dataf("extension %u", (unsigned)type); 3026 *out_alert = alert; 3027 return 0; 3028 } 3029 } 3030 3031 for (size_t i = 0; i < kNumExtensions; i++) { 3032 if (!(received & (1u << i))) { 3033 /* Extension wasn't observed so call the callback with a NULL 3034 * parameter. */ 3035 uint8_t alert = SSL_AD_DECODE_ERROR; 3036 if (!kExtensions[i].parse_serverhello(hs, &alert, NULL)) { 3037 OPENSSL_PUT_ERROR(SSL, SSL_R_MISSING_EXTENSION); 3038 ERR_add_error_dataf("extension %u", (unsigned)kExtensions[i].value); 3039 *out_alert = alert; 3040 return 0; 3041 } 3042 } 3043 } 3044 3045 return 1; 3046 } 3047 3048 static int ssl_check_clienthello_tlsext(SSL_HANDSHAKE *hs) { 3049 SSL *const ssl = hs->ssl; 3050 int ret = SSL_TLSEXT_ERR_NOACK; 3051 int al = SSL_AD_UNRECOGNIZED_NAME; 3052 3053 if (ssl->ctx->tlsext_servername_callback != 0) { 3054 ret = ssl->ctx->tlsext_servername_callback(ssl, &al, 3055 ssl->ctx->tlsext_servername_arg); 3056 } else if (ssl->session_ctx->tlsext_servername_callback != 0) { 3057 ret = ssl->session_ctx->tlsext_servername_callback( 3058 ssl, &al, ssl->session_ctx->tlsext_servername_arg); 3059 } 3060 3061 switch (ret) { 3062 case SSL_TLSEXT_ERR_ALERT_FATAL: 3063 ssl3_send_alert(ssl, SSL3_AL_FATAL, al); 3064 return -1; 3065 3066 case SSL_TLSEXT_ERR_NOACK: 3067 hs->should_ack_sni = 0; 3068 return 1; 3069 3070 default: 3071 return 1; 3072 } 3073 } 3074 3075 int ssl_parse_serverhello_tlsext(SSL_HANDSHAKE *hs, CBS *cbs) { 3076 SSL *const ssl = hs->ssl; 3077 int alert = SSL_AD_DECODE_ERROR; 3078 if (ssl_scan_serverhello_tlsext(hs, cbs, &alert) <= 0) { 3079 ssl3_send_alert(ssl, SSL3_AL_FATAL, alert); 3080 return 0; 3081 } 3082 3083 return 1; 3084 } 3085 3086 static enum ssl_ticket_aead_result_t 3087 ssl_decrypt_ticket_with_cipher_ctx(SSL *ssl, uint8_t **out, size_t *out_len, 3088 int *out_renew_ticket, const uint8_t *ticket, 3089 size_t ticket_len) { 3090 enum ssl_ticket_aead_result_t ret = ssl_ticket_aead_ignore_ticket; 3091 const SSL_CTX *const ssl_ctx = ssl->session_ctx; 3092 uint8_t *plaintext = NULL; 3093 3094 HMAC_CTX hmac_ctx; 3095 HMAC_CTX_init(&hmac_ctx); 3096 EVP_CIPHER_CTX cipher_ctx; 3097 EVP_CIPHER_CTX_init(&cipher_ctx); 3098 3099 /* Ensure there is room for the key name and the largest IV 3100 * |tlsext_ticket_key_cb| may try to consume. The real limit may be lower, but 3101 * the maximum IV length should be well under the minimum size for the 3102 * session material and HMAC. */ 3103 if (ticket_len < SSL_TICKET_KEY_NAME_LEN + EVP_MAX_IV_LENGTH) { 3104 goto out; 3105 } 3106 const uint8_t *iv = ticket + SSL_TICKET_KEY_NAME_LEN; 3107 3108 if (ssl_ctx->tlsext_ticket_key_cb != NULL) { 3109 int cb_ret = ssl_ctx->tlsext_ticket_key_cb( 3110 ssl, (uint8_t *)ticket /* name */, (uint8_t *)iv, &cipher_ctx, 3111 &hmac_ctx, 0 /* decrypt */); 3112 if (cb_ret < 0) { 3113 ret = ssl_ticket_aead_error; 3114 goto out; 3115 } else if (cb_ret == 0) { 3116 goto out; 3117 } else if (cb_ret == 2) { 3118 *out_renew_ticket = 1; 3119 } 3120 } else { 3121 /* Check the key name matches. */ 3122 if (OPENSSL_memcmp(ticket, ssl_ctx->tlsext_tick_key_name, 3123 SSL_TICKET_KEY_NAME_LEN) != 0) { 3124 goto out; 3125 } 3126 if (!HMAC_Init_ex(&hmac_ctx, ssl_ctx->tlsext_tick_hmac_key, 3127 sizeof(ssl_ctx->tlsext_tick_hmac_key), tlsext_tick_md(), 3128 NULL) || 3129 !EVP_DecryptInit_ex(&cipher_ctx, EVP_aes_128_cbc(), NULL, 3130 ssl_ctx->tlsext_tick_aes_key, iv)) { 3131 ret = ssl_ticket_aead_error; 3132 goto out; 3133 } 3134 } 3135 size_t iv_len = EVP_CIPHER_CTX_iv_length(&cipher_ctx); 3136 3137 /* Check the MAC at the end of the ticket. */ 3138 uint8_t mac[EVP_MAX_MD_SIZE]; 3139 size_t mac_len = HMAC_size(&hmac_ctx); 3140 if (ticket_len < SSL_TICKET_KEY_NAME_LEN + iv_len + 1 + mac_len) { 3141 /* The ticket must be large enough for key name, IV, data, and MAC. */ 3142 goto out; 3143 } 3144 HMAC_Update(&hmac_ctx, ticket, ticket_len - mac_len); 3145 HMAC_Final(&hmac_ctx, mac, NULL); 3146 int mac_ok = 3147 CRYPTO_memcmp(mac, ticket + (ticket_len - mac_len), mac_len) == 0; 3148 #if defined(BORINGSSL_UNSAFE_FUZZER_MODE) 3149 mac_ok = 1; 3150 #endif 3151 if (!mac_ok) { 3152 goto out; 3153 } 3154 3155 /* Decrypt the session data. */ 3156 const uint8_t *ciphertext = ticket + SSL_TICKET_KEY_NAME_LEN + iv_len; 3157 size_t ciphertext_len = ticket_len - SSL_TICKET_KEY_NAME_LEN - iv_len - 3158 mac_len; 3159 plaintext = OPENSSL_malloc(ciphertext_len); 3160 if (plaintext == NULL) { 3161 ret = ssl_ticket_aead_error; 3162 goto out; 3163 } 3164 size_t plaintext_len; 3165 #if defined(BORINGSSL_UNSAFE_FUZZER_MODE) 3166 OPENSSL_memcpy(plaintext, ciphertext, ciphertext_len); 3167 plaintext_len = ciphertext_len; 3168 #else 3169 if (ciphertext_len >= INT_MAX) { 3170 goto out; 3171 } 3172 int len1, len2; 3173 if (!EVP_DecryptUpdate(&cipher_ctx, plaintext, &len1, ciphertext, 3174 (int)ciphertext_len) || 3175 !EVP_DecryptFinal_ex(&cipher_ctx, plaintext + len1, &len2)) { 3176 ERR_clear_error(); 3177 goto out; 3178 } 3179 plaintext_len = (size_t)(len1) + len2; 3180 #endif 3181 3182 *out = plaintext; 3183 plaintext = NULL; 3184 *out_len = plaintext_len; 3185 ret = ssl_ticket_aead_success; 3186 3187 out: 3188 OPENSSL_free(plaintext); 3189 HMAC_CTX_cleanup(&hmac_ctx); 3190 EVP_CIPHER_CTX_cleanup(&cipher_ctx); 3191 return ret; 3192 } 3193 3194 static enum ssl_ticket_aead_result_t ssl_decrypt_ticket_with_method( 3195 SSL *ssl, uint8_t **out, size_t *out_len, int *out_renew_ticket, 3196 const uint8_t *ticket, size_t ticket_len) { 3197 uint8_t *plaintext = OPENSSL_malloc(ticket_len); 3198 if (plaintext == NULL) { 3199 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); 3200 return ssl_ticket_aead_error; 3201 } 3202 3203 size_t plaintext_len; 3204 const enum ssl_ticket_aead_result_t result = 3205 ssl->session_ctx->ticket_aead_method->open( 3206 ssl, plaintext, &plaintext_len, ticket_len, ticket, ticket_len); 3207 3208 if (result == ssl_ticket_aead_success) { 3209 *out = plaintext; 3210 plaintext = NULL; 3211 *out_len = plaintext_len; 3212 } 3213 3214 OPENSSL_free(plaintext); 3215 return result; 3216 } 3217 3218 enum ssl_ticket_aead_result_t ssl_process_ticket( 3219 SSL *ssl, SSL_SESSION **out_session, int *out_renew_ticket, 3220 const uint8_t *ticket, size_t ticket_len, const uint8_t *session_id, 3221 size_t session_id_len) { 3222 *out_renew_ticket = 0; 3223 *out_session = NULL; 3224 3225 if ((SSL_get_options(ssl) & SSL_OP_NO_TICKET) || 3226 session_id_len > SSL_MAX_SSL_SESSION_ID_LENGTH) { 3227 return ssl_ticket_aead_ignore_ticket; 3228 } 3229 3230 uint8_t *plaintext = NULL; 3231 size_t plaintext_len; 3232 enum ssl_ticket_aead_result_t result; 3233 if (ssl->session_ctx->ticket_aead_method != NULL) { 3234 result = ssl_decrypt_ticket_with_method( 3235 ssl, &plaintext, &plaintext_len, out_renew_ticket, ticket, ticket_len); 3236 } else { 3237 result = ssl_decrypt_ticket_with_cipher_ctx( 3238 ssl, &plaintext, &plaintext_len, out_renew_ticket, ticket, ticket_len); 3239 } 3240 3241 if (result != ssl_ticket_aead_success) { 3242 return result; 3243 } 3244 3245 /* Decode the session. */ 3246 SSL_SESSION *session = 3247 SSL_SESSION_from_bytes(plaintext, plaintext_len, ssl->ctx); 3248 OPENSSL_free(plaintext); 3249 3250 if (session == NULL) { 3251 ERR_clear_error(); /* Don't leave an error on the queue. */ 3252 return ssl_ticket_aead_ignore_ticket; 3253 } 3254 3255 /* Copy the client's session ID into the new session, to denote the ticket has 3256 * been accepted. */ 3257 OPENSSL_memcpy(session->session_id, session_id, session_id_len); 3258 session->session_id_length = session_id_len; 3259 3260 *out_session = session; 3261 return ssl_ticket_aead_success; 3262 } 3263 3264 int tls1_parse_peer_sigalgs(SSL_HANDSHAKE *hs, const CBS *in_sigalgs) { 3265 /* Extension ignored for inappropriate versions */ 3266 if (ssl3_protocol_version(hs->ssl) < TLS1_2_VERSION) { 3267 return 1; 3268 } 3269 3270 OPENSSL_free(hs->peer_sigalgs); 3271 hs->peer_sigalgs = NULL; 3272 hs->num_peer_sigalgs = 0; 3273 3274 size_t num_sigalgs = CBS_len(in_sigalgs); 3275 if (num_sigalgs % 2 != 0) { 3276 return 0; 3277 } 3278 num_sigalgs /= 2; 3279 3280 /* supported_signature_algorithms in the certificate request is 3281 * allowed to be empty. */ 3282 if (num_sigalgs == 0) { 3283 return 1; 3284 } 3285 3286 /* This multiplication doesn't overflow because sizeof(uint16_t) is two 3287 * and we just divided |num_sigalgs| by two. */ 3288 hs->peer_sigalgs = OPENSSL_malloc(num_sigalgs * sizeof(uint16_t)); 3289 if (hs->peer_sigalgs == NULL) { 3290 return 0; 3291 } 3292 hs->num_peer_sigalgs = num_sigalgs; 3293 3294 CBS sigalgs; 3295 CBS_init(&sigalgs, CBS_data(in_sigalgs), CBS_len(in_sigalgs)); 3296 for (size_t i = 0; i < num_sigalgs; i++) { 3297 if (!CBS_get_u16(&sigalgs, &hs->peer_sigalgs[i])) { 3298 return 0; 3299 } 3300 } 3301 3302 return 1; 3303 } 3304 3305 int tls1_choose_signature_algorithm(SSL_HANDSHAKE *hs, uint16_t *out) { 3306 SSL *const ssl = hs->ssl; 3307 CERT *cert = ssl->cert; 3308 3309 /* Before TLS 1.2, the signature algorithm isn't negotiated as part of the 3310 * handshake. It is fixed at MD5-SHA1 for RSA and SHA1 for ECDSA. */ 3311 if (ssl3_protocol_version(ssl) < TLS1_2_VERSION) { 3312 int type = ssl_private_key_type(ssl); 3313 if (type == NID_rsaEncryption) { 3314 *out = SSL_SIGN_RSA_PKCS1_MD5_SHA1; 3315 return 1; 3316 } 3317 if (ssl_is_ecdsa_key_type(type)) { 3318 *out = SSL_SIGN_ECDSA_SHA1; 3319 return 1; 3320 } 3321 OPENSSL_PUT_ERROR(SSL, SSL_R_NO_COMMON_SIGNATURE_ALGORITHMS); 3322 return 0; 3323 } 3324 3325 const uint16_t *sigalgs = cert->sigalgs; 3326 size_t num_sigalgs = cert->num_sigalgs; 3327 if (sigalgs == NULL) { 3328 sigalgs = kSignSignatureAlgorithms; 3329 num_sigalgs = OPENSSL_ARRAY_SIZE(kSignSignatureAlgorithms); 3330 } 3331 3332 const uint16_t *peer_sigalgs = hs->peer_sigalgs; 3333 size_t num_peer_sigalgs = hs->num_peer_sigalgs; 3334 if (num_peer_sigalgs == 0 && ssl3_protocol_version(ssl) < TLS1_3_VERSION) { 3335 /* If the client didn't specify any signature_algorithms extension then 3336 * we can assume that it supports SHA1. See 3337 * http://tools.ietf.org/html/rfc5246#section-7.4.1.4.1 */ 3338 static const uint16_t kDefaultPeerAlgorithms[] = {SSL_SIGN_RSA_PKCS1_SHA1, 3339 SSL_SIGN_ECDSA_SHA1}; 3340 peer_sigalgs = kDefaultPeerAlgorithms; 3341 num_peer_sigalgs = OPENSSL_ARRAY_SIZE(kDefaultPeerAlgorithms); 3342 } 3343 3344 for (size_t i = 0; i < num_sigalgs; i++) { 3345 uint16_t sigalg = sigalgs[i]; 3346 /* SSL_SIGN_RSA_PKCS1_MD5_SHA1 is an internal value and should never be 3347 * negotiated. */ 3348 if (sigalg == SSL_SIGN_RSA_PKCS1_MD5_SHA1 || 3349 !ssl_private_key_supports_signature_algorithm(ssl, sigalgs[i])) { 3350 continue; 3351 } 3352 3353 for (size_t j = 0; j < num_peer_sigalgs; j++) { 3354 if (sigalg == peer_sigalgs[j]) { 3355 *out = sigalg; 3356 return 1; 3357 } 3358 } 3359 } 3360 3361 OPENSSL_PUT_ERROR(SSL, SSL_R_NO_COMMON_SIGNATURE_ALGORITHMS); 3362 return 0; 3363 } 3364 3365 int tls1_verify_channel_id(SSL_HANDSHAKE *hs) { 3366 SSL *const ssl = hs->ssl; 3367 int ret = 0; 3368 uint16_t extension_type; 3369 CBS extension, channel_id; 3370 3371 /* A Channel ID handshake message is structured to contain multiple 3372 * extensions, but the only one that can be present is Channel ID. */ 3373 CBS_init(&channel_id, ssl->init_msg, ssl->init_num); 3374 if (!CBS_get_u16(&channel_id, &extension_type) || 3375 !CBS_get_u16_length_prefixed(&channel_id, &extension) || 3376 CBS_len(&channel_id) != 0 || 3377 extension_type != TLSEXT_TYPE_channel_id || 3378 CBS_len(&extension) != TLSEXT_CHANNEL_ID_SIZE) { 3379 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 3380 ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); 3381 return 0; 3382 } 3383 3384 EC_GROUP *p256 = EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1); 3385 if (!p256) { 3386 OPENSSL_PUT_ERROR(SSL, SSL_R_NO_P256_SUPPORT); 3387 return 0; 3388 } 3389 3390 EC_KEY *key = NULL; 3391 EC_POINT *point = NULL; 3392 BIGNUM x, y; 3393 ECDSA_SIG sig; 3394 BN_init(&x); 3395 BN_init(&y); 3396 sig.r = BN_new(); 3397 sig.s = BN_new(); 3398 if (sig.r == NULL || sig.s == NULL) { 3399 goto err; 3400 } 3401 3402 const uint8_t *p = CBS_data(&extension); 3403 if (BN_bin2bn(p + 0, 32, &x) == NULL || 3404 BN_bin2bn(p + 32, 32, &y) == NULL || 3405 BN_bin2bn(p + 64, 32, sig.r) == NULL || 3406 BN_bin2bn(p + 96, 32, sig.s) == NULL) { 3407 goto err; 3408 } 3409 3410 point = EC_POINT_new(p256); 3411 if (point == NULL || 3412 !EC_POINT_set_affine_coordinates_GFp(p256, point, &x, &y, NULL)) { 3413 goto err; 3414 } 3415 3416 key = EC_KEY_new(); 3417 if (key == NULL || 3418 !EC_KEY_set_group(key, p256) || 3419 !EC_KEY_set_public_key(key, point)) { 3420 goto err; 3421 } 3422 3423 uint8_t digest[EVP_MAX_MD_SIZE]; 3424 size_t digest_len; 3425 if (!tls1_channel_id_hash(hs, digest, &digest_len)) { 3426 goto err; 3427 } 3428 3429 int sig_ok = ECDSA_do_verify(digest, digest_len, &sig, key); 3430 #if defined(BORINGSSL_UNSAFE_FUZZER_MODE) 3431 sig_ok = 1; 3432 #endif 3433 if (!sig_ok) { 3434 OPENSSL_PUT_ERROR(SSL, SSL_R_CHANNEL_ID_SIGNATURE_INVALID); 3435 ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR); 3436 ssl->s3->tlsext_channel_id_valid = 0; 3437 goto err; 3438 } 3439 3440 OPENSSL_memcpy(ssl->s3->tlsext_channel_id, p, 64); 3441 ret = 1; 3442 3443 err: 3444 BN_free(&x); 3445 BN_free(&y); 3446 BN_free(sig.r); 3447 BN_free(sig.s); 3448 EC_KEY_free(key); 3449 EC_POINT_free(point); 3450 EC_GROUP_free(p256); 3451 return ret; 3452 } 3453 3454 int tls1_write_channel_id(SSL_HANDSHAKE *hs, CBB *cbb) { 3455 SSL *const ssl = hs->ssl; 3456 uint8_t digest[EVP_MAX_MD_SIZE]; 3457 size_t digest_len; 3458 if (!tls1_channel_id_hash(hs, digest, &digest_len)) { 3459 return 0; 3460 } 3461 3462 EC_KEY *ec_key = EVP_PKEY_get0_EC_KEY(ssl->tlsext_channel_id_private); 3463 if (ec_key == NULL) { 3464 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 3465 return 0; 3466 } 3467 3468 int ret = 0; 3469 BIGNUM *x = BN_new(); 3470 BIGNUM *y = BN_new(); 3471 ECDSA_SIG *sig = NULL; 3472 if (x == NULL || y == NULL || 3473 !EC_POINT_get_affine_coordinates_GFp(EC_KEY_get0_group(ec_key), 3474 EC_KEY_get0_public_key(ec_key), 3475 x, y, NULL)) { 3476 goto err; 3477 } 3478 3479 sig = ECDSA_do_sign(digest, digest_len, ec_key); 3480 if (sig == NULL) { 3481 goto err; 3482 } 3483 3484 CBB child; 3485 if (!CBB_add_u16(cbb, TLSEXT_TYPE_channel_id) || 3486 !CBB_add_u16_length_prefixed(cbb, &child) || 3487 !BN_bn2cbb_padded(&child, 32, x) || 3488 !BN_bn2cbb_padded(&child, 32, y) || 3489 !BN_bn2cbb_padded(&child, 32, sig->r) || 3490 !BN_bn2cbb_padded(&child, 32, sig->s) || 3491 !CBB_flush(cbb)) { 3492 goto err; 3493 } 3494 3495 ret = 1; 3496 3497 err: 3498 BN_free(x); 3499 BN_free(y); 3500 ECDSA_SIG_free(sig); 3501 return ret; 3502 } 3503 3504 int tls1_channel_id_hash(SSL_HANDSHAKE *hs, uint8_t *out, size_t *out_len) { 3505 SSL *const ssl = hs->ssl; 3506 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 3507 uint8_t *msg; 3508 size_t msg_len; 3509 if (!tls13_get_cert_verify_signature_input(hs, &msg, &msg_len, 3510 ssl_cert_verify_channel_id)) { 3511 return 0; 3512 } 3513 SHA256(msg, msg_len, out); 3514 *out_len = SHA256_DIGEST_LENGTH; 3515 OPENSSL_free(msg); 3516 return 1; 3517 } 3518 3519 SHA256_CTX ctx; 3520 3521 SHA256_Init(&ctx); 3522 static const char kClientIDMagic[] = "TLS Channel ID signature"; 3523 SHA256_Update(&ctx, kClientIDMagic, sizeof(kClientIDMagic)); 3524 3525 if (ssl->session != NULL) { 3526 static const char kResumptionMagic[] = "Resumption"; 3527 SHA256_Update(&ctx, kResumptionMagic, sizeof(kResumptionMagic)); 3528 if (ssl->session->original_handshake_hash_len == 0) { 3529 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 3530 return 0; 3531 } 3532 SHA256_Update(&ctx, ssl->session->original_handshake_hash, 3533 ssl->session->original_handshake_hash_len); 3534 } 3535 3536 uint8_t hs_hash[EVP_MAX_MD_SIZE]; 3537 size_t hs_hash_len; 3538 if (!SSL_TRANSCRIPT_get_hash(&hs->transcript, hs_hash, &hs_hash_len)) { 3539 return 0; 3540 } 3541 SHA256_Update(&ctx, hs_hash, (size_t)hs_hash_len); 3542 SHA256_Final(out, &ctx); 3543 *out_len = SHA256_DIGEST_LENGTH; 3544 return 1; 3545 } 3546 3547 /* tls1_record_handshake_hashes_for_channel_id records the current handshake 3548 * hashes in |hs->new_session| so that Channel ID resumptions can sign that 3549 * data. */ 3550 int tls1_record_handshake_hashes_for_channel_id(SSL_HANDSHAKE *hs) { 3551 SSL *const ssl = hs->ssl; 3552 /* This function should never be called for a resumed session because the 3553 * handshake hashes that we wish to record are for the original, full 3554 * handshake. */ 3555 if (ssl->session != NULL) { 3556 return -1; 3557 } 3558 3559 OPENSSL_COMPILE_ASSERT( 3560 sizeof(hs->new_session->original_handshake_hash) == EVP_MAX_MD_SIZE, 3561 original_handshake_hash_is_too_small); 3562 3563 size_t digest_len; 3564 if (!SSL_TRANSCRIPT_get_hash(&hs->transcript, 3565 hs->new_session->original_handshake_hash, 3566 &digest_len)) { 3567 return -1; 3568 } 3569 3570 OPENSSL_COMPILE_ASSERT(EVP_MAX_MD_SIZE <= 0xff, max_md_size_is_too_large); 3571 hs->new_session->original_handshake_hash_len = (uint8_t)digest_len; 3572 3573 return 1; 3574 } 3575 3576 int ssl_do_channel_id_callback(SSL *ssl) { 3577 if (ssl->tlsext_channel_id_private != NULL || 3578 ssl->ctx->channel_id_cb == NULL) { 3579 return 1; 3580 } 3581 3582 EVP_PKEY *key = NULL; 3583 ssl->ctx->channel_id_cb(ssl, &key); 3584 if (key == NULL) { 3585 /* The caller should try again later. */ 3586 return 1; 3587 } 3588 3589 int ret = SSL_set1_tls_channel_id(ssl, key); 3590 EVP_PKEY_free(key); 3591 return ret; 3592 } 3593 3594 int ssl_is_sct_list_valid(const CBS *contents) { 3595 /* Shallow parse the SCT list for sanity. By the RFC 3596 * (https://tools.ietf.org/html/rfc6962#section-3.3) neither the list nor any 3597 * of the SCTs may be empty. */ 3598 CBS copy = *contents; 3599 CBS sct_list; 3600 if (!CBS_get_u16_length_prefixed(©, &sct_list) || 3601 CBS_len(©) != 0 || 3602 CBS_len(&sct_list) == 0) { 3603 return 0; 3604 } 3605 3606 while (CBS_len(&sct_list) > 0) { 3607 CBS sct; 3608 if (!CBS_get_u16_length_prefixed(&sct_list, &sct) || 3609 CBS_len(&sct) == 0) { 3610 return 0; 3611 } 3612 } 3613 3614 return 1; 3615 } 3616
