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> 124 125 #include "internal.h" 126 #include "../crypto/internal.h" 127 128 129 static int ssl_check_clienthello_tlsext(SSL_HANDSHAKE *hs); 130 131 static int compare_uint16_t(const void *p1, const void *p2) { 132 uint16_t u1 = *((const uint16_t *)p1); 133 uint16_t u2 = *((const uint16_t *)p2); 134 if (u1 < u2) { 135 return -1; 136 } else if (u1 > u2) { 137 return 1; 138 } else { 139 return 0; 140 } 141 } 142 143 /* Per http://tools.ietf.org/html/rfc5246#section-7.4.1.4, there may not be 144 * more than one extension of the same type in a ClientHello or ServerHello. 145 * This function does an initial scan over the extensions block to filter those 146 * out. */ 147 static int tls1_check_duplicate_extensions(const CBS *cbs) { 148 CBS extensions = *cbs; 149 size_t num_extensions = 0, i = 0; 150 uint16_t *extension_types = NULL; 151 int ret = 0; 152 153 /* First pass: count the extensions. */ 154 while (CBS_len(&extensions) > 0) { 155 uint16_t type; 156 CBS extension; 157 158 if (!CBS_get_u16(&extensions, &type) || 159 !CBS_get_u16_length_prefixed(&extensions, &extension)) { 160 goto done; 161 } 162 163 num_extensions++; 164 } 165 166 if (num_extensions == 0) { 167 return 1; 168 } 169 170 extension_types = 171 (uint16_t *)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 = (uint16_t *)OPENSSL_malloc(ncurves * sizeof(uint16_t)); 366 if (group_ids == NULL) { 367 return 0; 368 } 369 370 for (size_t i = 0; i < ncurves; i++) { 371 if (!ssl_nid_to_group_id(&group_ids[i], curves[i])) { 372 OPENSSL_free(group_ids); 373 return 0; 374 } 375 } 376 377 OPENSSL_free(*out_group_ids); 378 *out_group_ids = group_ids; 379 *out_group_ids_len = ncurves; 380 381 return 1; 382 } 383 384 int tls1_set_curves_list(uint16_t **out_group_ids, size_t *out_group_ids_len, 385 const char *curves) { 386 uint16_t *group_ids = NULL; 387 size_t ncurves = 0; 388 389 const char *col; 390 const char *ptr = curves; 391 392 do { 393 col = strchr(ptr, ':'); 394 395 uint16_t group_id; 396 if (!ssl_name_to_group_id(&group_id, ptr, 397 col ? (size_t)(col - ptr) : strlen(ptr))) { 398 goto err; 399 } 400 401 uint16_t *new_group_ids = (uint16_t *)OPENSSL_realloc( 402 group_ids, (ncurves + 1) * sizeof(uint16_t)); 403 if (new_group_ids == NULL) { 404 goto err; 405 } 406 group_ids = new_group_ids; 407 408 group_ids[ncurves] = group_id; 409 ncurves++; 410 411 if (col) { 412 ptr = col + 1; 413 } 414 } while (col); 415 416 OPENSSL_free(*out_group_ids); 417 *out_group_ids = group_ids; 418 *out_group_ids_len = ncurves; 419 420 return 1; 421 422 err: 423 OPENSSL_free(group_ids); 424 return 0; 425 } 426 427 int tls1_check_group_id(SSL *ssl, uint16_t group_id) { 428 const uint16_t *groups; 429 size_t groups_len; 430 tls1_get_grouplist(ssl, &groups, &groups_len); 431 for (size_t i = 0; i < groups_len; i++) { 432 if (groups[i] == group_id) { 433 return 1; 434 } 435 } 436 437 return 0; 438 } 439 440 /* kVerifySignatureAlgorithms is the default list of accepted signature 441 * algorithms for verifying. 442 * 443 * For now, RSA-PSS signature algorithms are not enabled on Android's system 444 * BoringSSL. Once the change in Chrome has stuck and the values are finalized, 445 * restore them. */ 446 static const uint16_t kVerifySignatureAlgorithms[] = { 447 /* List our preferred algorithms first. */ 448 SSL_SIGN_ED25519, 449 SSL_SIGN_ECDSA_SECP256R1_SHA256, 450 #if !defined(BORINGSSL_ANDROID_SYSTEM) 451 SSL_SIGN_RSA_PSS_SHA256, 452 #endif 453 SSL_SIGN_RSA_PKCS1_SHA256, 454 455 /* Larger hashes are acceptable. */ 456 SSL_SIGN_ECDSA_SECP384R1_SHA384, 457 #if !defined(BORINGSSL_ANDROID_SYSTEM) 458 SSL_SIGN_RSA_PSS_SHA384, 459 #endif 460 SSL_SIGN_RSA_PKCS1_SHA384, 461 462 /* TODO(davidben): Remove this. */ 463 #if defined(BORINGSSL_ANDROID_SYSTEM) 464 SSL_SIGN_ECDSA_SECP521R1_SHA512, 465 #endif 466 #if !defined(BORINGSSL_ANDROID_SYSTEM) 467 SSL_SIGN_RSA_PSS_SHA512, 468 #endif 469 SSL_SIGN_RSA_PKCS1_SHA512, 470 471 /* For now, SHA-1 is still accepted but least preferable. */ 472 SSL_SIGN_RSA_PKCS1_SHA1, 473 474 }; 475 476 /* kSignSignatureAlgorithms is the default list of supported signature 477 * algorithms for signing. 478 * 479 * For now, RSA-PSS signature algorithms are not enabled on Android's system 480 * BoringSSL. Once the change in Chrome has stuck and the values are finalized, 481 * restore them. */ 482 static const uint16_t kSignSignatureAlgorithms[] = { 483 /* List our preferred algorithms first. */ 484 SSL_SIGN_ED25519, 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 void SSL_CTX_set_ed25519_enabled(SSL_CTX *ctx, int enabled) { 512 ctx->ed25519_enabled = !!enabled; 513 } 514 515 int tls12_add_verify_sigalgs(const SSL *ssl, CBB *out) { 516 const uint16_t *sigalgs = kVerifySignatureAlgorithms; 517 size_t num_sigalgs = OPENSSL_ARRAY_SIZE(kVerifySignatureAlgorithms); 518 if (ssl->ctx->num_verify_sigalgs != 0) { 519 sigalgs = ssl->ctx->verify_sigalgs; 520 num_sigalgs = ssl->ctx->num_verify_sigalgs; 521 } 522 523 for (size_t i = 0; i < num_sigalgs; i++) { 524 if (sigalgs == kVerifySignatureAlgorithms && 525 sigalgs[i] == SSL_SIGN_ED25519 && 526 !ssl->ctx->ed25519_enabled) { 527 continue; 528 } 529 if (!CBB_add_u16(out, sigalgs[i])) { 530 return 0; 531 } 532 } 533 534 return 1; 535 } 536 537 int tls12_check_peer_sigalg(SSL *ssl, uint8_t *out_alert, uint16_t sigalg) { 538 const uint16_t *sigalgs = kVerifySignatureAlgorithms; 539 size_t num_sigalgs = OPENSSL_ARRAY_SIZE(kVerifySignatureAlgorithms); 540 if (ssl->ctx->num_verify_sigalgs != 0) { 541 sigalgs = ssl->ctx->verify_sigalgs; 542 num_sigalgs = ssl->ctx->num_verify_sigalgs; 543 } 544 545 for (size_t i = 0; i < num_sigalgs; i++) { 546 if (sigalgs == kVerifySignatureAlgorithms && 547 sigalgs[i] == SSL_SIGN_ED25519 && 548 !ssl->ctx->ed25519_enabled) { 549 continue; 550 } 551 if (sigalg == sigalgs[i]) { 552 return 1; 553 } 554 } 555 556 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SIGNATURE_TYPE); 557 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 558 return 0; 559 } 560 561 /* tls_extension represents a TLS extension that is handled internally. The 562 * |init| function is called for each handshake, before any other functions of 563 * the extension. Then the add and parse callbacks are called as needed. 564 * 565 * The parse callbacks receive a |CBS| that contains the contents of the 566 * extension (i.e. not including the type and length bytes). If an extension is 567 * not received then the parse callbacks will be called with a NULL CBS so that 568 * they can do any processing needed to handle the absence of an extension. 569 * 570 * The add callbacks receive a |CBB| to which the extension can be appended but 571 * the function is responsible for appending the type and length bytes too. 572 * 573 * All callbacks return one for success and zero for error. If a parse function 574 * returns zero then a fatal alert with value |*out_alert| will be sent. If 575 * |*out_alert| isn't set, then a |decode_error| alert will be sent. */ 576 struct tls_extension { 577 uint16_t value; 578 void (*init)(SSL_HANDSHAKE *hs); 579 580 int (*add_clienthello)(SSL_HANDSHAKE *hs, CBB *out); 581 int (*parse_serverhello)(SSL_HANDSHAKE *hs, uint8_t *out_alert, 582 CBS *contents); 583 584 int (*parse_clienthello)(SSL_HANDSHAKE *hs, uint8_t *out_alert, 585 CBS *contents); 586 int (*add_serverhello)(SSL_HANDSHAKE *hs, CBB *out); 587 }; 588 589 static int forbid_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 590 CBS *contents) { 591 if (contents != NULL) { 592 /* Servers MUST NOT send this extension. */ 593 *out_alert = SSL_AD_UNSUPPORTED_EXTENSION; 594 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION); 595 return 0; 596 } 597 598 return 1; 599 } 600 601 static int ignore_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 602 CBS *contents) { 603 /* This extension from the client is handled elsewhere. */ 604 return 1; 605 } 606 607 static int dont_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 608 return 1; 609 } 610 611 /* Server name indication (SNI). 612 * 613 * https://tools.ietf.org/html/rfc6066#section-3. */ 614 615 static int ext_sni_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 616 SSL *const ssl = hs->ssl; 617 if (ssl->tlsext_hostname == NULL) { 618 return 1; 619 } 620 621 CBB contents, server_name_list, name; 622 if (!CBB_add_u16(out, TLSEXT_TYPE_server_name) || 623 !CBB_add_u16_length_prefixed(out, &contents) || 624 !CBB_add_u16_length_prefixed(&contents, &server_name_list) || 625 !CBB_add_u8(&server_name_list, TLSEXT_NAMETYPE_host_name) || 626 !CBB_add_u16_length_prefixed(&server_name_list, &name) || 627 !CBB_add_bytes(&name, (const uint8_t *)ssl->tlsext_hostname, 628 strlen(ssl->tlsext_hostname)) || 629 !CBB_flush(out)) { 630 return 0; 631 } 632 633 return 1; 634 } 635 636 static int ext_sni_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 637 CBS *contents) { 638 SSL *const ssl = hs->ssl; 639 if (contents == NULL) { 640 return 1; 641 } 642 643 if (CBS_len(contents) != 0) { 644 return 0; 645 } 646 647 assert(ssl->tlsext_hostname != NULL); 648 649 if (ssl->session == NULL) { 650 OPENSSL_free(hs->new_session->tlsext_hostname); 651 hs->new_session->tlsext_hostname = BUF_strdup(ssl->tlsext_hostname); 652 if (!hs->new_session->tlsext_hostname) { 653 *out_alert = SSL_AD_INTERNAL_ERROR; 654 return 0; 655 } 656 } 657 658 return 1; 659 } 660 661 static int ext_sni_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 662 CBS *contents) { 663 if (contents == NULL) { 664 return 1; 665 } 666 667 CBS server_name_list, host_name; 668 uint8_t name_type; 669 if (!CBS_get_u16_length_prefixed(contents, &server_name_list) || 670 !CBS_get_u8(&server_name_list, &name_type) || 671 /* Although the server_name extension was intended to be extensible to 672 * new name types and multiple names, OpenSSL 1.0.x had a bug which meant 673 * different name types will cause an error. Further, RFC 4366 originally 674 * defined syntax inextensibly. RFC 6066 corrected this mistake, but 675 * adding new name types is no longer feasible. 676 * 677 * Act as if the extensibility does not exist to simplify parsing. */ 678 !CBS_get_u16_length_prefixed(&server_name_list, &host_name) || 679 CBS_len(&server_name_list) != 0 || 680 CBS_len(contents) != 0) { 681 return 0; 682 } 683 684 if (name_type != TLSEXT_NAMETYPE_host_name || 685 CBS_len(&host_name) == 0 || 686 CBS_len(&host_name) > TLSEXT_MAXLEN_host_name || 687 CBS_contains_zero_byte(&host_name)) { 688 *out_alert = SSL_AD_UNRECOGNIZED_NAME; 689 return 0; 690 } 691 692 /* Copy the hostname as a string. */ 693 if (!CBS_strdup(&host_name, &hs->hostname)) { 694 *out_alert = SSL_AD_INTERNAL_ERROR; 695 return 0; 696 } 697 698 hs->should_ack_sni = 1; 699 return 1; 700 } 701 702 static int ext_sni_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 703 if (hs->ssl->s3->session_reused || 704 !hs->should_ack_sni) { 705 return 1; 706 } 707 708 if (!CBB_add_u16(out, TLSEXT_TYPE_server_name) || 709 !CBB_add_u16(out, 0 /* length */)) { 710 return 0; 711 } 712 713 return 1; 714 } 715 716 717 /* Renegotiation indication. 718 * 719 * https://tools.ietf.org/html/rfc5746 */ 720 721 static int ext_ri_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 722 SSL *const ssl = hs->ssl; 723 /* Renegotiation indication is not necessary in TLS 1.3. */ 724 if (hs->min_version >= TLS1_3_VERSION) { 725 return 1; 726 } 727 728 assert(ssl->s3->initial_handshake_complete == 729 (ssl->s3->previous_client_finished_len != 0)); 730 731 CBB contents, prev_finished; 732 if (!CBB_add_u16(out, TLSEXT_TYPE_renegotiate) || 733 !CBB_add_u16_length_prefixed(out, &contents) || 734 !CBB_add_u8_length_prefixed(&contents, &prev_finished) || 735 !CBB_add_bytes(&prev_finished, ssl->s3->previous_client_finished, 736 ssl->s3->previous_client_finished_len) || 737 !CBB_flush(out)) { 738 return 0; 739 } 740 741 return 1; 742 } 743 744 static int ext_ri_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 745 CBS *contents) { 746 SSL *const ssl = hs->ssl; 747 if (contents != NULL && ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 748 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 749 return 0; 750 } 751 752 /* Servers may not switch between omitting the extension and supporting it. 753 * See RFC 5746, sections 3.5 and 4.2. */ 754 if (ssl->s3->initial_handshake_complete && 755 (contents != NULL) != ssl->s3->send_connection_binding) { 756 *out_alert = SSL_AD_HANDSHAKE_FAILURE; 757 OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH); 758 return 0; 759 } 760 761 if (contents == NULL) { 762 /* Strictly speaking, if we want to avoid an attack we should *always* see 763 * RI even on initial ServerHello because the client doesn't see any 764 * renegotiation during an attack. However this would mean we could not 765 * connect to any server which doesn't support RI. 766 * 767 * OpenSSL has |SSL_OP_LEGACY_SERVER_CONNECT| to control this, but in 768 * practical terms every client sets it so it's just assumed here. */ 769 return 1; 770 } 771 772 const size_t expected_len = ssl->s3->previous_client_finished_len + 773 ssl->s3->previous_server_finished_len; 774 775 /* Check for logic errors */ 776 assert(!expected_len || ssl->s3->previous_client_finished_len); 777 assert(!expected_len || ssl->s3->previous_server_finished_len); 778 assert(ssl->s3->initial_handshake_complete == 779 (ssl->s3->previous_client_finished_len != 0)); 780 assert(ssl->s3->initial_handshake_complete == 781 (ssl->s3->previous_server_finished_len != 0)); 782 783 /* Parse out the extension contents. */ 784 CBS renegotiated_connection; 785 if (!CBS_get_u8_length_prefixed(contents, &renegotiated_connection) || 786 CBS_len(contents) != 0) { 787 OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_ENCODING_ERR); 788 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 789 return 0; 790 } 791 792 /* Check that the extension matches. */ 793 if (CBS_len(&renegotiated_connection) != expected_len) { 794 OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH); 795 *out_alert = SSL_AD_HANDSHAKE_FAILURE; 796 return 0; 797 } 798 799 const uint8_t *d = CBS_data(&renegotiated_connection); 800 int ok = CRYPTO_memcmp(d, ssl->s3->previous_client_finished, 801 ssl->s3->previous_client_finished_len) == 0; 802 #if defined(BORINGSSL_UNSAFE_FUZZER_MODE) 803 ok = 1; 804 #endif 805 if (!ok) { 806 OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH); 807 *out_alert = SSL_AD_HANDSHAKE_FAILURE; 808 return 0; 809 } 810 d += ssl->s3->previous_client_finished_len; 811 812 ok = CRYPTO_memcmp(d, ssl->s3->previous_server_finished, 813 ssl->s3->previous_server_finished_len) == 0; 814 #if defined(BORINGSSL_UNSAFE_FUZZER_MODE) 815 ok = 1; 816 #endif 817 if (!ok) { 818 OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH); 819 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 820 return 0; 821 } 822 ssl->s3->send_connection_binding = 1; 823 824 return 1; 825 } 826 827 static int ext_ri_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 828 CBS *contents) { 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 (contents == NULL) { 839 return 1; 840 } 841 842 CBS renegotiated_connection; 843 if (!CBS_get_u8_length_prefixed(contents, &renegotiated_connection) || 844 CBS_len(contents) != 0) { 845 OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_ENCODING_ERR); 846 return 0; 847 } 848 849 /* Check that the extension matches. We do not support renegotiation as a 850 * server, so this must be empty. */ 851 if (CBS_len(&renegotiated_connection) != 0) { 852 OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH); 853 *out_alert = SSL_AD_HANDSHAKE_FAILURE; 854 return 0; 855 } 856 857 ssl->s3->send_connection_binding = 1; 858 859 return 1; 860 } 861 862 static int ext_ri_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 863 SSL *const ssl = hs->ssl; 864 /* Renegotiation isn't supported as a server so this function should never be 865 * called after the initial handshake. */ 866 assert(!ssl->s3->initial_handshake_complete); 867 868 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 869 return 1; 870 } 871 872 if (!CBB_add_u16(out, TLSEXT_TYPE_renegotiate) || 873 !CBB_add_u16(out, 1 /* length */) || 874 !CBB_add_u8(out, 0 /* empty renegotiation info */)) { 875 return 0; 876 } 877 878 return 1; 879 } 880 881 882 /* Extended Master Secret. 883 * 884 * https://tools.ietf.org/html/rfc7627 */ 885 886 static int ext_ems_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 887 /* Extended master secret is not necessary in TLS 1.3. */ 888 if (hs->min_version >= TLS1_3_VERSION || hs->max_version <= SSL3_VERSION) { 889 return 1; 890 } 891 892 if (!CBB_add_u16(out, TLSEXT_TYPE_extended_master_secret) || 893 !CBB_add_u16(out, 0 /* length */)) { 894 return 0; 895 } 896 897 return 1; 898 } 899 900 static int ext_ems_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 901 CBS *contents) { 902 SSL *const ssl = hs->ssl; 903 904 if (contents != NULL) { 905 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION || 906 ssl->version == SSL3_VERSION || 907 CBS_len(contents) != 0) { 908 return 0; 909 } 910 911 hs->extended_master_secret = 1; 912 } 913 914 /* Whether EMS is negotiated may not change on renegotiation. */ 915 if (ssl->s3->established_session != NULL && 916 hs->extended_master_secret != 917 ssl->s3->established_session->extended_master_secret) { 918 OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_EMS_MISMATCH); 919 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 920 return 0; 921 } 922 923 return 1; 924 } 925 926 static int ext_ems_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 927 CBS *contents) { 928 uint16_t version = ssl3_protocol_version(hs->ssl); 929 if (version >= TLS1_3_VERSION || 930 version == SSL3_VERSION) { 931 return 1; 932 } 933 934 if (contents == NULL) { 935 return 1; 936 } 937 938 if (CBS_len(contents) != 0) { 939 return 0; 940 } 941 942 hs->extended_master_secret = 1; 943 return 1; 944 } 945 946 static int ext_ems_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 947 if (!hs->extended_master_secret) { 948 return 1; 949 } 950 951 if (!CBB_add_u16(out, TLSEXT_TYPE_extended_master_secret) || 952 !CBB_add_u16(out, 0 /* length */)) { 953 return 0; 954 } 955 956 return 1; 957 } 958 959 960 /* Session tickets. 961 * 962 * https://tools.ietf.org/html/rfc5077 */ 963 964 static int ext_ticket_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 965 SSL *const ssl = hs->ssl; 966 /* TLS 1.3 uses a different ticket extension. */ 967 if (hs->min_version >= TLS1_3_VERSION || 968 SSL_get_options(ssl) & SSL_OP_NO_TICKET) { 969 return 1; 970 } 971 972 const uint8_t *ticket_data = NULL; 973 int ticket_len = 0; 974 975 /* Renegotiation does not participate in session resumption. However, still 976 * advertise the extension to avoid potentially breaking servers which carry 977 * over the state from the previous handshake, such as OpenSSL servers 978 * without upstream's 3c3f0259238594d77264a78944d409f2127642c4. */ 979 if (!ssl->s3->initial_handshake_complete && 980 ssl->session != NULL && 981 ssl->session->tlsext_tick != NULL && 982 /* Don't send TLS 1.3 session tickets in the ticket extension. */ 983 SSL_SESSION_protocol_version(ssl->session) < TLS1_3_VERSION) { 984 ticket_data = ssl->session->tlsext_tick; 985 ticket_len = ssl->session->tlsext_ticklen; 986 } 987 988 CBB ticket; 989 if (!CBB_add_u16(out, TLSEXT_TYPE_session_ticket) || 990 !CBB_add_u16_length_prefixed(out, &ticket) || 991 !CBB_add_bytes(&ticket, ticket_data, ticket_len) || 992 !CBB_flush(out)) { 993 return 0; 994 } 995 996 return 1; 997 } 998 999 static int ext_ticket_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1000 CBS *contents) { 1001 SSL *const ssl = hs->ssl; 1002 if (contents == NULL) { 1003 return 1; 1004 } 1005 1006 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 1007 return 0; 1008 } 1009 1010 /* If |SSL_OP_NO_TICKET| is set then no extension will have been sent and 1011 * this function should never be called, even if the server tries to send the 1012 * extension. */ 1013 assert((SSL_get_options(ssl) & SSL_OP_NO_TICKET) == 0); 1014 1015 if (CBS_len(contents) != 0) { 1016 return 0; 1017 } 1018 1019 hs->ticket_expected = 1; 1020 return 1; 1021 } 1022 1023 static int ext_ticket_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 1024 if (!hs->ticket_expected) { 1025 return 1; 1026 } 1027 1028 /* If |SSL_OP_NO_TICKET| is set, |ticket_expected| should never be true. */ 1029 assert((SSL_get_options(hs->ssl) & SSL_OP_NO_TICKET) == 0); 1030 1031 if (!CBB_add_u16(out, TLSEXT_TYPE_session_ticket) || 1032 !CBB_add_u16(out, 0 /* length */)) { 1033 return 0; 1034 } 1035 1036 return 1; 1037 } 1038 1039 1040 /* Signature Algorithms. 1041 * 1042 * https://tools.ietf.org/html/rfc5246#section-7.4.1.4.1 */ 1043 1044 static int ext_sigalgs_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 1045 SSL *const ssl = hs->ssl; 1046 if (hs->max_version < TLS1_2_VERSION) { 1047 return 1; 1048 } 1049 1050 CBB contents, sigalgs_cbb; 1051 if (!CBB_add_u16(out, TLSEXT_TYPE_signature_algorithms) || 1052 !CBB_add_u16_length_prefixed(out, &contents) || 1053 !CBB_add_u16_length_prefixed(&contents, &sigalgs_cbb) || 1054 !tls12_add_verify_sigalgs(ssl, &sigalgs_cbb) || 1055 !CBB_flush(out)) { 1056 return 0; 1057 } 1058 1059 return 1; 1060 } 1061 1062 static int ext_sigalgs_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1063 CBS *contents) { 1064 OPENSSL_free(hs->peer_sigalgs); 1065 hs->peer_sigalgs = NULL; 1066 hs->num_peer_sigalgs = 0; 1067 1068 if (contents == NULL) { 1069 return 1; 1070 } 1071 1072 CBS supported_signature_algorithms; 1073 if (!CBS_get_u16_length_prefixed(contents, &supported_signature_algorithms) || 1074 CBS_len(contents) != 0 || 1075 CBS_len(&supported_signature_algorithms) == 0 || 1076 !tls1_parse_peer_sigalgs(hs, &supported_signature_algorithms)) { 1077 return 0; 1078 } 1079 1080 return 1; 1081 } 1082 1083 1084 /* OCSP Stapling. 1085 * 1086 * https://tools.ietf.org/html/rfc6066#section-8 */ 1087 1088 static int ext_ocsp_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 1089 SSL *const ssl = hs->ssl; 1090 if (!ssl->ocsp_stapling_enabled) { 1091 return 1; 1092 } 1093 1094 CBB contents; 1095 if (!CBB_add_u16(out, TLSEXT_TYPE_status_request) || 1096 !CBB_add_u16_length_prefixed(out, &contents) || 1097 !CBB_add_u8(&contents, TLSEXT_STATUSTYPE_ocsp) || 1098 !CBB_add_u16(&contents, 0 /* empty responder ID list */) || 1099 !CBB_add_u16(&contents, 0 /* empty request extensions */) || 1100 !CBB_flush(out)) { 1101 return 0; 1102 } 1103 1104 return 1; 1105 } 1106 1107 static int ext_ocsp_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1108 CBS *contents) { 1109 SSL *const ssl = hs->ssl; 1110 if (contents == NULL) { 1111 return 1; 1112 } 1113 1114 /* TLS 1.3 OCSP responses are included in the Certificate extensions. */ 1115 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 1116 return 0; 1117 } 1118 1119 /* OCSP stapling is forbidden on non-certificate ciphers. */ 1120 if (CBS_len(contents) != 0 || 1121 !ssl_cipher_uses_certificate_auth(hs->new_cipher)) { 1122 return 0; 1123 } 1124 1125 /* Note this does not check for resumption in TLS 1.2. Sending 1126 * status_request here does not make sense, but OpenSSL does so and the 1127 * specification does not say anything. Tolerate it but ignore it. */ 1128 1129 hs->certificate_status_expected = 1; 1130 return 1; 1131 } 1132 1133 static int ext_ocsp_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1134 CBS *contents) { 1135 if (contents == NULL) { 1136 return 1; 1137 } 1138 1139 uint8_t status_type; 1140 if (!CBS_get_u8(contents, &status_type)) { 1141 return 0; 1142 } 1143 1144 /* We cannot decide whether OCSP stapling will occur yet because the correct 1145 * SSL_CTX might not have been selected. */ 1146 hs->ocsp_stapling_requested = status_type == TLSEXT_STATUSTYPE_ocsp; 1147 1148 return 1; 1149 } 1150 1151 static int ext_ocsp_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 1152 SSL *const ssl = hs->ssl; 1153 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION || 1154 !hs->ocsp_stapling_requested || 1155 ssl->cert->ocsp_response == NULL || 1156 ssl->s3->session_reused || 1157 !ssl_cipher_uses_certificate_auth(hs->new_cipher)) { 1158 return 1; 1159 } 1160 1161 hs->certificate_status_expected = 1; 1162 1163 return CBB_add_u16(out, TLSEXT_TYPE_status_request) && 1164 CBB_add_u16(out, 0 /* length */); 1165 } 1166 1167 1168 /* Next protocol negotiation. 1169 * 1170 * https://htmlpreview.github.io/?https://github.com/agl/technotes/blob/master/nextprotoneg.html */ 1171 1172 static int ext_npn_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 1173 SSL *const ssl = hs->ssl; 1174 if (ssl->s3->initial_handshake_complete || 1175 ssl->ctx->next_proto_select_cb == NULL || 1176 SSL_is_dtls(ssl)) { 1177 return 1; 1178 } 1179 1180 if (!CBB_add_u16(out, TLSEXT_TYPE_next_proto_neg) || 1181 !CBB_add_u16(out, 0 /* length */)) { 1182 return 0; 1183 } 1184 1185 return 1; 1186 } 1187 1188 static int ext_npn_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1189 CBS *contents) { 1190 SSL *const ssl = hs->ssl; 1191 if (contents == NULL) { 1192 return 1; 1193 } 1194 1195 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 1196 return 0; 1197 } 1198 1199 /* If any of these are false then we should never have sent the NPN 1200 * extension in the ClientHello and thus this function should never have been 1201 * called. */ 1202 assert(!ssl->s3->initial_handshake_complete); 1203 assert(!SSL_is_dtls(ssl)); 1204 assert(ssl->ctx->next_proto_select_cb != NULL); 1205 1206 if (ssl->s3->alpn_selected != NULL) { 1207 /* NPN and ALPN may not be negotiated in the same connection. */ 1208 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 1209 OPENSSL_PUT_ERROR(SSL, SSL_R_NEGOTIATED_BOTH_NPN_AND_ALPN); 1210 return 0; 1211 } 1212 1213 const uint8_t *const orig_contents = CBS_data(contents); 1214 const size_t orig_len = CBS_len(contents); 1215 1216 while (CBS_len(contents) != 0) { 1217 CBS proto; 1218 if (!CBS_get_u8_length_prefixed(contents, &proto) || 1219 CBS_len(&proto) == 0) { 1220 return 0; 1221 } 1222 } 1223 1224 uint8_t *selected; 1225 uint8_t selected_len; 1226 if (ssl->ctx->next_proto_select_cb( 1227 ssl, &selected, &selected_len, orig_contents, orig_len, 1228 ssl->ctx->next_proto_select_cb_arg) != SSL_TLSEXT_ERR_OK) { 1229 *out_alert = SSL_AD_INTERNAL_ERROR; 1230 return 0; 1231 } 1232 1233 OPENSSL_free(ssl->s3->next_proto_negotiated); 1234 ssl->s3->next_proto_negotiated = 1235 (uint8_t *)BUF_memdup(selected, selected_len); 1236 if (ssl->s3->next_proto_negotiated == NULL) { 1237 *out_alert = SSL_AD_INTERNAL_ERROR; 1238 return 0; 1239 } 1240 1241 ssl->s3->next_proto_negotiated_len = selected_len; 1242 hs->next_proto_neg_seen = 1; 1243 1244 return 1; 1245 } 1246 1247 static int ext_npn_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1248 CBS *contents) { 1249 SSL *const ssl = hs->ssl; 1250 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 1251 return 1; 1252 } 1253 1254 if (contents != NULL && CBS_len(contents) != 0) { 1255 return 0; 1256 } 1257 1258 if (contents == NULL || 1259 ssl->s3->initial_handshake_complete || 1260 ssl->ctx->next_protos_advertised_cb == NULL || 1261 SSL_is_dtls(ssl)) { 1262 return 1; 1263 } 1264 1265 hs->next_proto_neg_seen = 1; 1266 return 1; 1267 } 1268 1269 static int ext_npn_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 1270 SSL *const ssl = hs->ssl; 1271 /* |next_proto_neg_seen| might have been cleared when an ALPN extension was 1272 * parsed. */ 1273 if (!hs->next_proto_neg_seen) { 1274 return 1; 1275 } 1276 1277 const uint8_t *npa; 1278 unsigned npa_len; 1279 1280 if (ssl->ctx->next_protos_advertised_cb( 1281 ssl, &npa, &npa_len, ssl->ctx->next_protos_advertised_cb_arg) != 1282 SSL_TLSEXT_ERR_OK) { 1283 hs->next_proto_neg_seen = 0; 1284 return 1; 1285 } 1286 1287 CBB contents; 1288 if (!CBB_add_u16(out, TLSEXT_TYPE_next_proto_neg) || 1289 !CBB_add_u16_length_prefixed(out, &contents) || 1290 !CBB_add_bytes(&contents, npa, npa_len) || 1291 !CBB_flush(out)) { 1292 return 0; 1293 } 1294 1295 return 1; 1296 } 1297 1298 1299 /* Signed certificate timestamps. 1300 * 1301 * https://tools.ietf.org/html/rfc6962#section-3.3.1 */ 1302 1303 static int ext_sct_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 1304 SSL *const ssl = hs->ssl; 1305 if (!ssl->signed_cert_timestamps_enabled) { 1306 return 1; 1307 } 1308 1309 if (!CBB_add_u16(out, TLSEXT_TYPE_certificate_timestamp) || 1310 !CBB_add_u16(out, 0 /* length */)) { 1311 return 0; 1312 } 1313 1314 return 1; 1315 } 1316 1317 static int ext_sct_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1318 CBS *contents) { 1319 SSL *const ssl = hs->ssl; 1320 if (contents == NULL) { 1321 return 1; 1322 } 1323 1324 /* TLS 1.3 SCTs are included in the Certificate extensions. */ 1325 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 1326 *out_alert = SSL_AD_DECODE_ERROR; 1327 return 0; 1328 } 1329 1330 /* If this is false then we should never have sent the SCT extension in the 1331 * ClientHello and thus this function should never have been called. */ 1332 assert(ssl->signed_cert_timestamps_enabled); 1333 1334 if (!ssl_is_sct_list_valid(contents)) { 1335 *out_alert = SSL_AD_DECODE_ERROR; 1336 return 0; 1337 } 1338 1339 /* Session resumption uses the original session information. The extension 1340 * should not be sent on resumption, but RFC 6962 did not make it a 1341 * requirement, so tolerate this. 1342 * 1343 * TODO(davidben): Enforce this anyway. */ 1344 if (!ssl->s3->session_reused && 1345 !CBS_stow(contents, &hs->new_session->tlsext_signed_cert_timestamp_list, 1346 &hs->new_session->tlsext_signed_cert_timestamp_list_length)) { 1347 *out_alert = SSL_AD_INTERNAL_ERROR; 1348 return 0; 1349 } 1350 1351 return 1; 1352 } 1353 1354 static int ext_sct_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1355 CBS *contents) { 1356 if (contents == NULL) { 1357 return 1; 1358 } 1359 1360 if (CBS_len(contents) != 0) { 1361 return 0; 1362 } 1363 1364 hs->scts_requested = 1; 1365 return 1; 1366 } 1367 1368 static int ext_sct_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 1369 SSL *const ssl = hs->ssl; 1370 /* The extension shouldn't be sent when resuming sessions. */ 1371 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION || 1372 ssl->s3->session_reused || 1373 ssl->cert->signed_cert_timestamp_list == NULL) { 1374 return 1; 1375 } 1376 1377 CBB contents; 1378 return CBB_add_u16(out, TLSEXT_TYPE_certificate_timestamp) && 1379 CBB_add_u16_length_prefixed(out, &contents) && 1380 CBB_add_bytes( 1381 &contents, 1382 CRYPTO_BUFFER_data(ssl->cert->signed_cert_timestamp_list), 1383 CRYPTO_BUFFER_len(ssl->cert->signed_cert_timestamp_list)) && 1384 CBB_flush(out); 1385 } 1386 1387 1388 /* Application-level Protocol Negotiation. 1389 * 1390 * https://tools.ietf.org/html/rfc7301 */ 1391 1392 static int ext_alpn_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 1393 SSL *const ssl = hs->ssl; 1394 if (ssl->alpn_client_proto_list == NULL || 1395 ssl->s3->initial_handshake_complete) { 1396 return 1; 1397 } 1398 1399 CBB contents, proto_list; 1400 if (!CBB_add_u16(out, TLSEXT_TYPE_application_layer_protocol_negotiation) || 1401 !CBB_add_u16_length_prefixed(out, &contents) || 1402 !CBB_add_u16_length_prefixed(&contents, &proto_list) || 1403 !CBB_add_bytes(&proto_list, ssl->alpn_client_proto_list, 1404 ssl->alpn_client_proto_list_len) || 1405 !CBB_flush(out)) { 1406 return 0; 1407 } 1408 1409 return 1; 1410 } 1411 1412 static int ext_alpn_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1413 CBS *contents) { 1414 SSL *const ssl = hs->ssl; 1415 if (contents == NULL) { 1416 return 1; 1417 } 1418 1419 assert(!ssl->s3->initial_handshake_complete); 1420 assert(ssl->alpn_client_proto_list != NULL); 1421 1422 if (hs->next_proto_neg_seen) { 1423 /* NPN and ALPN may not be negotiated in the same connection. */ 1424 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 1425 OPENSSL_PUT_ERROR(SSL, SSL_R_NEGOTIATED_BOTH_NPN_AND_ALPN); 1426 return 0; 1427 } 1428 1429 /* The extension data consists of a ProtocolNameList which must have 1430 * exactly one ProtocolName. Each of these is length-prefixed. */ 1431 CBS protocol_name_list, protocol_name; 1432 if (!CBS_get_u16_length_prefixed(contents, &protocol_name_list) || 1433 CBS_len(contents) != 0 || 1434 !CBS_get_u8_length_prefixed(&protocol_name_list, &protocol_name) || 1435 /* Empty protocol names are forbidden. */ 1436 CBS_len(&protocol_name) == 0 || 1437 CBS_len(&protocol_name_list) != 0) { 1438 return 0; 1439 } 1440 1441 if (!ssl->ctx->allow_unknown_alpn_protos) { 1442 /* Check that the protocol name is one of the ones we advertised. */ 1443 int protocol_ok = 0; 1444 CBS client_protocol_name_list, client_protocol_name; 1445 CBS_init(&client_protocol_name_list, ssl->alpn_client_proto_list, 1446 ssl->alpn_client_proto_list_len); 1447 while (CBS_len(&client_protocol_name_list) > 0) { 1448 if (!CBS_get_u8_length_prefixed(&client_protocol_name_list, 1449 &client_protocol_name)) { 1450 *out_alert = SSL_AD_INTERNAL_ERROR; 1451 return 0; 1452 } 1453 1454 if (CBS_len(&client_protocol_name) == CBS_len(&protocol_name) && 1455 OPENSSL_memcmp(CBS_data(&client_protocol_name), 1456 CBS_data(&protocol_name), 1457 CBS_len(&protocol_name)) == 0) { 1458 protocol_ok = 1; 1459 break; 1460 } 1461 } 1462 1463 if (!protocol_ok) { 1464 OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_ALPN_PROTOCOL); 1465 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 1466 return 0; 1467 } 1468 } 1469 1470 if (!CBS_stow(&protocol_name, &ssl->s3->alpn_selected, 1471 &ssl->s3->alpn_selected_len)) { 1472 *out_alert = SSL_AD_INTERNAL_ERROR; 1473 return 0; 1474 } 1475 1476 return 1; 1477 } 1478 1479 int ssl_negotiate_alpn(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1480 const SSL_CLIENT_HELLO *client_hello) { 1481 SSL *const ssl = hs->ssl; 1482 CBS contents; 1483 if (ssl->ctx->alpn_select_cb == NULL || 1484 !ssl_client_hello_get_extension( 1485 client_hello, &contents, 1486 TLSEXT_TYPE_application_layer_protocol_negotiation)) { 1487 /* Ignore ALPN if not configured or no extension was supplied. */ 1488 return 1; 1489 } 1490 1491 /* ALPN takes precedence over NPN. */ 1492 hs->next_proto_neg_seen = 0; 1493 1494 CBS protocol_name_list; 1495 if (!CBS_get_u16_length_prefixed(&contents, &protocol_name_list) || 1496 CBS_len(&contents) != 0 || 1497 CBS_len(&protocol_name_list) < 2) { 1498 OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT); 1499 *out_alert = SSL_AD_DECODE_ERROR; 1500 return 0; 1501 } 1502 1503 /* Validate the protocol list. */ 1504 CBS protocol_name_list_copy = protocol_name_list; 1505 while (CBS_len(&protocol_name_list_copy) > 0) { 1506 CBS protocol_name; 1507 1508 if (!CBS_get_u8_length_prefixed(&protocol_name_list_copy, &protocol_name) || 1509 /* Empty protocol names are forbidden. */ 1510 CBS_len(&protocol_name) == 0) { 1511 OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT); 1512 *out_alert = SSL_AD_DECODE_ERROR; 1513 return 0; 1514 } 1515 } 1516 1517 const uint8_t *selected; 1518 uint8_t selected_len; 1519 if (ssl->ctx->alpn_select_cb( 1520 ssl, &selected, &selected_len, CBS_data(&protocol_name_list), 1521 CBS_len(&protocol_name_list), 1522 ssl->ctx->alpn_select_cb_arg) == SSL_TLSEXT_ERR_OK) { 1523 OPENSSL_free(ssl->s3->alpn_selected); 1524 ssl->s3->alpn_selected = (uint8_t *)BUF_memdup(selected, selected_len); 1525 if (ssl->s3->alpn_selected == NULL) { 1526 *out_alert = SSL_AD_INTERNAL_ERROR; 1527 return 0; 1528 } 1529 ssl->s3->alpn_selected_len = selected_len; 1530 } 1531 1532 return 1; 1533 } 1534 1535 static int ext_alpn_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 1536 SSL *const ssl = hs->ssl; 1537 if (ssl->s3->alpn_selected == NULL) { 1538 return 1; 1539 } 1540 1541 CBB contents, proto_list, proto; 1542 if (!CBB_add_u16(out, TLSEXT_TYPE_application_layer_protocol_negotiation) || 1543 !CBB_add_u16_length_prefixed(out, &contents) || 1544 !CBB_add_u16_length_prefixed(&contents, &proto_list) || 1545 !CBB_add_u8_length_prefixed(&proto_list, &proto) || 1546 !CBB_add_bytes(&proto, ssl->s3->alpn_selected, 1547 ssl->s3->alpn_selected_len) || 1548 !CBB_flush(out)) { 1549 return 0; 1550 } 1551 1552 return 1; 1553 } 1554 1555 1556 /* Channel ID. 1557 * 1558 * https://tools.ietf.org/html/draft-balfanz-tls-channelid-01 */ 1559 1560 static void ext_channel_id_init(SSL_HANDSHAKE *hs) { 1561 hs->ssl->s3->tlsext_channel_id_valid = 0; 1562 } 1563 1564 static int ext_channel_id_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 1565 SSL *const ssl = hs->ssl; 1566 if (!ssl->tlsext_channel_id_enabled || 1567 SSL_is_dtls(ssl)) { 1568 return 1; 1569 } 1570 1571 if (!CBB_add_u16(out, TLSEXT_TYPE_channel_id) || 1572 !CBB_add_u16(out, 0 /* length */)) { 1573 return 0; 1574 } 1575 1576 return 1; 1577 } 1578 1579 static int ext_channel_id_parse_serverhello(SSL_HANDSHAKE *hs, 1580 uint8_t *out_alert, CBS *contents) { 1581 SSL *const ssl = hs->ssl; 1582 if (contents == NULL) { 1583 return 1; 1584 } 1585 1586 assert(!SSL_is_dtls(ssl)); 1587 assert(ssl->tlsext_channel_id_enabled); 1588 1589 if (CBS_len(contents) != 0) { 1590 return 0; 1591 } 1592 1593 ssl->s3->tlsext_channel_id_valid = 1; 1594 return 1; 1595 } 1596 1597 static int ext_channel_id_parse_clienthello(SSL_HANDSHAKE *hs, 1598 uint8_t *out_alert, CBS *contents) { 1599 SSL *const ssl = hs->ssl; 1600 if (contents == NULL || 1601 !ssl->tlsext_channel_id_enabled || 1602 SSL_is_dtls(ssl)) { 1603 return 1; 1604 } 1605 1606 if (CBS_len(contents) != 0) { 1607 return 0; 1608 } 1609 1610 ssl->s3->tlsext_channel_id_valid = 1; 1611 return 1; 1612 } 1613 1614 static int ext_channel_id_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 1615 SSL *const ssl = hs->ssl; 1616 if (!ssl->s3->tlsext_channel_id_valid) { 1617 return 1; 1618 } 1619 1620 if (!CBB_add_u16(out, TLSEXT_TYPE_channel_id) || 1621 !CBB_add_u16(out, 0 /* length */)) { 1622 return 0; 1623 } 1624 1625 return 1; 1626 } 1627 1628 1629 /* Secure Real-time Transport Protocol (SRTP) extension. 1630 * 1631 * https://tools.ietf.org/html/rfc5764 */ 1632 1633 1634 static void ext_srtp_init(SSL_HANDSHAKE *hs) { 1635 hs->ssl->srtp_profile = NULL; 1636 } 1637 1638 static int ext_srtp_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 1639 SSL *const ssl = hs->ssl; 1640 STACK_OF(SRTP_PROTECTION_PROFILE) *profiles = SSL_get_srtp_profiles(ssl); 1641 if (profiles == NULL) { 1642 return 1; 1643 } 1644 const size_t num_profiles = sk_SRTP_PROTECTION_PROFILE_num(profiles); 1645 if (num_profiles == 0) { 1646 return 1; 1647 } 1648 1649 CBB contents, profile_ids; 1650 if (!CBB_add_u16(out, TLSEXT_TYPE_srtp) || 1651 !CBB_add_u16_length_prefixed(out, &contents) || 1652 !CBB_add_u16_length_prefixed(&contents, &profile_ids)) { 1653 return 0; 1654 } 1655 1656 for (size_t i = 0; i < num_profiles; i++) { 1657 if (!CBB_add_u16(&profile_ids, 1658 sk_SRTP_PROTECTION_PROFILE_value(profiles, i)->id)) { 1659 return 0; 1660 } 1661 } 1662 1663 if (!CBB_add_u8(&contents, 0 /* empty use_mki value */) || 1664 !CBB_flush(out)) { 1665 return 0; 1666 } 1667 1668 return 1; 1669 } 1670 1671 static int ext_srtp_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1672 CBS *contents) { 1673 SSL *const ssl = hs->ssl; 1674 if (contents == NULL) { 1675 return 1; 1676 } 1677 1678 /* The extension consists of a u16-prefixed profile ID list containing a 1679 * single uint16_t profile ID, then followed by a u8-prefixed srtp_mki field. 1680 * 1681 * See https://tools.ietf.org/html/rfc5764#section-4.1.1 */ 1682 CBS profile_ids, srtp_mki; 1683 uint16_t profile_id; 1684 if (!CBS_get_u16_length_prefixed(contents, &profile_ids) || 1685 !CBS_get_u16(&profile_ids, &profile_id) || 1686 CBS_len(&profile_ids) != 0 || 1687 !CBS_get_u8_length_prefixed(contents, &srtp_mki) || 1688 CBS_len(contents) != 0) { 1689 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST); 1690 return 0; 1691 } 1692 1693 if (CBS_len(&srtp_mki) != 0) { 1694 /* Must be no MKI, since we never offer one. */ 1695 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_MKI_VALUE); 1696 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 1697 return 0; 1698 } 1699 1700 STACK_OF(SRTP_PROTECTION_PROFILE) *profiles = SSL_get_srtp_profiles(ssl); 1701 1702 /* Check to see if the server gave us something we support (and presumably 1703 * offered). */ 1704 for (size_t i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(profiles); i++) { 1705 const SRTP_PROTECTION_PROFILE *profile = 1706 sk_SRTP_PROTECTION_PROFILE_value(profiles, i); 1707 1708 if (profile->id == profile_id) { 1709 ssl->srtp_profile = profile; 1710 return 1; 1711 } 1712 } 1713 1714 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST); 1715 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 1716 return 0; 1717 } 1718 1719 static int ext_srtp_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1720 CBS *contents) { 1721 SSL *const ssl = hs->ssl; 1722 if (contents == NULL) { 1723 return 1; 1724 } 1725 1726 CBS profile_ids, srtp_mki; 1727 if (!CBS_get_u16_length_prefixed(contents, &profile_ids) || 1728 CBS_len(&profile_ids) < 2 || 1729 !CBS_get_u8_length_prefixed(contents, &srtp_mki) || 1730 CBS_len(contents) != 0) { 1731 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST); 1732 return 0; 1733 } 1734 /* Discard the MKI value for now. */ 1735 1736 const STACK_OF(SRTP_PROTECTION_PROFILE) *server_profiles = 1737 SSL_get_srtp_profiles(ssl); 1738 1739 /* Pick the server's most preferred profile. */ 1740 for (size_t i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(server_profiles); i++) { 1741 const SRTP_PROTECTION_PROFILE *server_profile = 1742 sk_SRTP_PROTECTION_PROFILE_value(server_profiles, i); 1743 1744 CBS profile_ids_tmp; 1745 CBS_init(&profile_ids_tmp, CBS_data(&profile_ids), CBS_len(&profile_ids)); 1746 1747 while (CBS_len(&profile_ids_tmp) > 0) { 1748 uint16_t profile_id; 1749 if (!CBS_get_u16(&profile_ids_tmp, &profile_id)) { 1750 return 0; 1751 } 1752 1753 if (server_profile->id == profile_id) { 1754 ssl->srtp_profile = server_profile; 1755 return 1; 1756 } 1757 } 1758 } 1759 1760 return 1; 1761 } 1762 1763 static int ext_srtp_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 1764 SSL *const ssl = hs->ssl; 1765 if (ssl->srtp_profile == NULL) { 1766 return 1; 1767 } 1768 1769 CBB contents, profile_ids; 1770 if (!CBB_add_u16(out, TLSEXT_TYPE_srtp) || 1771 !CBB_add_u16_length_prefixed(out, &contents) || 1772 !CBB_add_u16_length_prefixed(&contents, &profile_ids) || 1773 !CBB_add_u16(&profile_ids, ssl->srtp_profile->id) || 1774 !CBB_add_u8(&contents, 0 /* empty MKI */) || 1775 !CBB_flush(out)) { 1776 return 0; 1777 } 1778 1779 return 1; 1780 } 1781 1782 1783 /* EC point formats. 1784 * 1785 * https://tools.ietf.org/html/rfc4492#section-5.1.2 */ 1786 1787 static int ext_ec_point_add_extension(SSL_HANDSHAKE *hs, CBB *out) { 1788 CBB contents, formats; 1789 if (!CBB_add_u16(out, TLSEXT_TYPE_ec_point_formats) || 1790 !CBB_add_u16_length_prefixed(out, &contents) || 1791 !CBB_add_u8_length_prefixed(&contents, &formats) || 1792 !CBB_add_u8(&formats, TLSEXT_ECPOINTFORMAT_uncompressed) || 1793 !CBB_flush(out)) { 1794 return 0; 1795 } 1796 1797 return 1; 1798 } 1799 1800 static int ext_ec_point_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 1801 /* The point format extension is unneccessary in TLS 1.3. */ 1802 if (hs->min_version >= TLS1_3_VERSION) { 1803 return 1; 1804 } 1805 1806 return ext_ec_point_add_extension(hs, out); 1807 } 1808 1809 static int ext_ec_point_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1810 CBS *contents) { 1811 if (contents == NULL) { 1812 return 1; 1813 } 1814 1815 if (ssl3_protocol_version(hs->ssl) >= TLS1_3_VERSION) { 1816 return 0; 1817 } 1818 1819 CBS ec_point_format_list; 1820 if (!CBS_get_u8_length_prefixed(contents, &ec_point_format_list) || 1821 CBS_len(contents) != 0) { 1822 return 0; 1823 } 1824 1825 /* Per RFC 4492, section 5.1.2, implementations MUST support the uncompressed 1826 * point format. */ 1827 if (OPENSSL_memchr(CBS_data(&ec_point_format_list), 1828 TLSEXT_ECPOINTFORMAT_uncompressed, 1829 CBS_len(&ec_point_format_list)) == NULL) { 1830 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 1831 return 0; 1832 } 1833 1834 return 1; 1835 } 1836 1837 static int ext_ec_point_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert, 1838 CBS *contents) { 1839 if (ssl3_protocol_version(hs->ssl) >= TLS1_3_VERSION) { 1840 return 1; 1841 } 1842 1843 return ext_ec_point_parse_serverhello(hs, out_alert, contents); 1844 } 1845 1846 static int ext_ec_point_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 1847 SSL *const ssl = hs->ssl; 1848 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 1849 return 1; 1850 } 1851 1852 const uint32_t alg_k = hs->new_cipher->algorithm_mkey; 1853 const uint32_t alg_a = hs->new_cipher->algorithm_auth; 1854 const int using_ecc = (alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA); 1855 1856 if (!using_ecc) { 1857 return 1; 1858 } 1859 1860 return ext_ec_point_add_extension(hs, out); 1861 } 1862 1863 1864 /* Pre Shared Key 1865 * 1866 * https://tools.ietf.org/html/draft-ietf-tls-tls13-18#section-4.2.6 */ 1867 1868 static size_t ext_pre_shared_key_clienthello_length(SSL_HANDSHAKE *hs) { 1869 SSL *const ssl = hs->ssl; 1870 if (hs->max_version < TLS1_3_VERSION || ssl->session == NULL || 1871 SSL_SESSION_protocol_version(ssl->session) < TLS1_3_VERSION) { 1872 return 0; 1873 } 1874 1875 size_t binder_len = EVP_MD_size(SSL_SESSION_get_digest(ssl->session)); 1876 return 15 + ssl->session->tlsext_ticklen + binder_len; 1877 } 1878 1879 static int ext_pre_shared_key_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 1880 SSL *const ssl = hs->ssl; 1881 if (hs->max_version < TLS1_3_VERSION || ssl->session == NULL || 1882 SSL_SESSION_protocol_version(ssl->session) < TLS1_3_VERSION) { 1883 return 1; 1884 } 1885 1886 struct OPENSSL_timeval now; 1887 ssl_get_current_time(ssl, &now); 1888 uint32_t ticket_age = 1000 * (now.tv_sec - ssl->session->time); 1889 uint32_t obfuscated_ticket_age = ticket_age + ssl->session->ticket_age_add; 1890 1891 /* Fill in a placeholder zero binder of the appropriate length. It will be 1892 * computed and filled in later after length prefixes are computed. */ 1893 uint8_t zero_binder[EVP_MAX_MD_SIZE] = {0}; 1894 size_t binder_len = EVP_MD_size(SSL_SESSION_get_digest(ssl->session)); 1895 1896 CBB contents, identity, ticket, binders, binder; 1897 if (!CBB_add_u16(out, TLSEXT_TYPE_pre_shared_key) || 1898 !CBB_add_u16_length_prefixed(out, &contents) || 1899 !CBB_add_u16_length_prefixed(&contents, &identity) || 1900 !CBB_add_u16_length_prefixed(&identity, &ticket) || 1901 !CBB_add_bytes(&ticket, ssl->session->tlsext_tick, 1902 ssl->session->tlsext_ticklen) || 1903 !CBB_add_u32(&identity, obfuscated_ticket_age) || 1904 !CBB_add_u16_length_prefixed(&contents, &binders) || 1905 !CBB_add_u8_length_prefixed(&binders, &binder) || 1906 !CBB_add_bytes(&binder, zero_binder, binder_len)) { 1907 return 0; 1908 } 1909 1910 hs->needs_psk_binder = 1; 1911 return CBB_flush(out); 1912 } 1913 1914 int ssl_ext_pre_shared_key_parse_serverhello(SSL_HANDSHAKE *hs, 1915 uint8_t *out_alert, 1916 CBS *contents) { 1917 uint16_t psk_id; 1918 if (!CBS_get_u16(contents, &psk_id) || 1919 CBS_len(contents) != 0) { 1920 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 1921 *out_alert = SSL_AD_DECODE_ERROR; 1922 return 0; 1923 } 1924 1925 /* We only advertise one PSK identity, so the only legal index is zero. */ 1926 if (psk_id != 0) { 1927 OPENSSL_PUT_ERROR(SSL, SSL_R_PSK_IDENTITY_NOT_FOUND); 1928 *out_alert = SSL_AD_UNKNOWN_PSK_IDENTITY; 1929 return 0; 1930 } 1931 1932 return 1; 1933 } 1934 1935 int ssl_ext_pre_shared_key_parse_clienthello( 1936 SSL_HANDSHAKE *hs, CBS *out_ticket, CBS *out_binders, 1937 uint32_t *out_obfuscated_ticket_age, uint8_t *out_alert, CBS *contents) { 1938 /* We only process the first PSK identity since we don't support pure PSK. */ 1939 CBS identities, binders; 1940 if (!CBS_get_u16_length_prefixed(contents, &identities) || 1941 !CBS_get_u16_length_prefixed(&identities, out_ticket) || 1942 !CBS_get_u32(&identities, out_obfuscated_ticket_age) || 1943 !CBS_get_u16_length_prefixed(contents, &binders) || 1944 CBS_len(&binders) == 0 || 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 *out_binders = binders; 1952 1953 /* Check the syntax of the remaining identities, but do not process them. */ 1954 size_t num_identities = 1; 1955 while (CBS_len(&identities) != 0) { 1956 CBS unused_ticket; 1957 uint32_t unused_obfuscated_ticket_age; 1958 if (!CBS_get_u16_length_prefixed(&identities, &unused_ticket) || 1959 !CBS_get_u32(&identities, &unused_obfuscated_ticket_age)) { 1960 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 1961 *out_alert = SSL_AD_DECODE_ERROR; 1962 return 0; 1963 } 1964 1965 num_identities++; 1966 } 1967 1968 /* Check the syntax of the binders. The value will be checked later if 1969 * resuming. */ 1970 size_t num_binders = 0; 1971 while (CBS_len(&binders) != 0) { 1972 CBS binder; 1973 if (!CBS_get_u8_length_prefixed(&binders, &binder)) { 1974 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 1975 *out_alert = SSL_AD_DECODE_ERROR; 1976 return 0; 1977 } 1978 1979 num_binders++; 1980 } 1981 1982 if (num_identities != num_binders) { 1983 OPENSSL_PUT_ERROR(SSL, SSL_R_PSK_IDENTITY_BINDER_COUNT_MISMATCH); 1984 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 1985 return 0; 1986 } 1987 1988 return 1; 1989 } 1990 1991 int ssl_ext_pre_shared_key_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 1992 if (!hs->ssl->s3->session_reused) { 1993 return 1; 1994 } 1995 1996 CBB contents; 1997 if (!CBB_add_u16(out, TLSEXT_TYPE_pre_shared_key) || 1998 !CBB_add_u16_length_prefixed(out, &contents) || 1999 /* We only consider the first identity for resumption */ 2000 !CBB_add_u16(&contents, 0) || 2001 !CBB_flush(out)) { 2002 return 0; 2003 } 2004 2005 return 1; 2006 } 2007 2008 2009 /* Pre-Shared Key Exchange Modes 2010 * 2011 * https://tools.ietf.org/html/draft-ietf-tls-tls13-18#section-4.2.7 */ 2012 2013 static int ext_psk_key_exchange_modes_add_clienthello(SSL_HANDSHAKE *hs, 2014 CBB *out) { 2015 if (hs->max_version < TLS1_3_VERSION) { 2016 return 1; 2017 } 2018 2019 CBB contents, ke_modes; 2020 if (!CBB_add_u16(out, TLSEXT_TYPE_psk_key_exchange_modes) || 2021 !CBB_add_u16_length_prefixed(out, &contents) || 2022 !CBB_add_u8_length_prefixed(&contents, &ke_modes) || 2023 !CBB_add_u8(&ke_modes, SSL_PSK_DHE_KE)) { 2024 return 0; 2025 } 2026 2027 return CBB_flush(out); 2028 } 2029 2030 static int ext_psk_key_exchange_modes_parse_clienthello(SSL_HANDSHAKE *hs, 2031 uint8_t *out_alert, 2032 CBS *contents) { 2033 if (contents == NULL) { 2034 return 1; 2035 } 2036 2037 CBS ke_modes; 2038 if (!CBS_get_u8_length_prefixed(contents, &ke_modes) || 2039 CBS_len(&ke_modes) == 0 || 2040 CBS_len(contents) != 0) { 2041 *out_alert = SSL_AD_DECODE_ERROR; 2042 return 0; 2043 } 2044 2045 /* We only support tickets with PSK_DHE_KE. */ 2046 hs->accept_psk_mode = OPENSSL_memchr(CBS_data(&ke_modes), SSL_PSK_DHE_KE, 2047 CBS_len(&ke_modes)) != NULL; 2048 2049 return 1; 2050 } 2051 2052 2053 /* Early Data Indication 2054 * 2055 * https://tools.ietf.org/html/draft-ietf-tls-tls13-18#section-4.2.8 */ 2056 2057 static int ext_early_data_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 2058 SSL *const ssl = hs->ssl; 2059 if (ssl->session == NULL || 2060 SSL_SESSION_protocol_version(ssl->session) < TLS1_3_VERSION || 2061 ssl->session->ticket_max_early_data == 0 || 2062 hs->received_hello_retry_request || 2063 !ssl->cert->enable_early_data) { 2064 return 1; 2065 } 2066 2067 hs->early_data_offered = 1; 2068 2069 if (!CBB_add_u16(out, TLSEXT_TYPE_early_data) || 2070 !CBB_add_u16(out, 0) || 2071 !CBB_flush(out)) { 2072 return 0; 2073 } 2074 2075 return 1; 2076 } 2077 2078 static int ext_early_data_parse_serverhello(SSL_HANDSHAKE *hs, 2079 uint8_t *out_alert, CBS *contents) { 2080 SSL *const ssl = hs->ssl; 2081 if (contents == NULL) { 2082 return 1; 2083 } 2084 2085 if (CBS_len(contents) != 0) { 2086 *out_alert = SSL_AD_DECODE_ERROR; 2087 return 0; 2088 } 2089 2090 if (!ssl->s3->session_reused) { 2091 *out_alert = SSL_AD_UNSUPPORTED_EXTENSION; 2092 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION); 2093 return 0; 2094 } 2095 2096 ssl->early_data_accepted = 1; 2097 return 1; 2098 } 2099 2100 static int ext_early_data_parse_clienthello(SSL_HANDSHAKE *hs, 2101 uint8_t *out_alert, CBS *contents) { 2102 SSL *const ssl = hs->ssl; 2103 if (contents == NULL || 2104 ssl3_protocol_version(ssl) < TLS1_3_VERSION) { 2105 return 1; 2106 } 2107 2108 if (CBS_len(contents) != 0) { 2109 *out_alert = SSL_AD_DECODE_ERROR; 2110 return 0; 2111 } 2112 2113 hs->early_data_offered = 1; 2114 return 1; 2115 } 2116 2117 static int ext_early_data_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 2118 if (!hs->ssl->early_data_accepted) { 2119 return 1; 2120 } 2121 2122 if (!CBB_add_u16(out, TLSEXT_TYPE_early_data) || 2123 !CBB_add_u16(out, 0) || 2124 !CBB_flush(out)) { 2125 return 0; 2126 } 2127 2128 return 1; 2129 } 2130 2131 2132 /* Key Share 2133 * 2134 * https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.5 */ 2135 2136 static int ext_key_share_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 2137 SSL *const ssl = hs->ssl; 2138 if (hs->max_version < TLS1_3_VERSION) { 2139 return 1; 2140 } 2141 2142 CBB contents, kse_bytes; 2143 if (!CBB_add_u16(out, TLSEXT_TYPE_key_share) || 2144 !CBB_add_u16_length_prefixed(out, &contents) || 2145 !CBB_add_u16_length_prefixed(&contents, &kse_bytes)) { 2146 return 0; 2147 } 2148 2149 uint16_t group_id = hs->retry_group; 2150 if (hs->received_hello_retry_request) { 2151 /* We received a HelloRetryRequest without a new curve, so there is no new 2152 * share to append. Leave |ecdh_ctx| as-is. */ 2153 if (group_id == 0 && 2154 !CBB_add_bytes(&kse_bytes, hs->key_share_bytes, 2155 hs->key_share_bytes_len)) { 2156 return 0; 2157 } 2158 OPENSSL_free(hs->key_share_bytes); 2159 hs->key_share_bytes = NULL; 2160 hs->key_share_bytes_len = 0; 2161 if (group_id == 0) { 2162 return CBB_flush(out); 2163 } 2164 } else { 2165 /* Add a fake group. See draft-davidben-tls-grease-01. */ 2166 if (ssl->ctx->grease_enabled && 2167 (!CBB_add_u16(&kse_bytes, 2168 ssl_get_grease_value(ssl, ssl_grease_group)) || 2169 !CBB_add_u16(&kse_bytes, 1 /* length */) || 2170 !CBB_add_u8(&kse_bytes, 0 /* one byte key share */))) { 2171 return 0; 2172 } 2173 2174 /* Predict the most preferred group. */ 2175 const uint16_t *groups; 2176 size_t groups_len; 2177 tls1_get_grouplist(ssl, &groups, &groups_len); 2178 if (groups_len == 0) { 2179 OPENSSL_PUT_ERROR(SSL, SSL_R_NO_GROUPS_SPECIFIED); 2180 return 0; 2181 } 2182 2183 group_id = groups[0]; 2184 } 2185 2186 CBB key_exchange; 2187 if (!CBB_add_u16(&kse_bytes, group_id) || 2188 !CBB_add_u16_length_prefixed(&kse_bytes, &key_exchange) || 2189 !SSL_ECDH_CTX_init(&hs->ecdh_ctx, group_id) || 2190 !SSL_ECDH_CTX_offer(&hs->ecdh_ctx, &key_exchange) || 2191 !CBB_flush(&kse_bytes)) { 2192 return 0; 2193 } 2194 2195 if (!hs->received_hello_retry_request) { 2196 /* Save the contents of the extension to repeat it in the second 2197 * ClientHello. */ 2198 hs->key_share_bytes_len = CBB_len(&kse_bytes); 2199 hs->key_share_bytes = 2200 (uint8_t *)BUF_memdup(CBB_data(&kse_bytes), CBB_len(&kse_bytes)); 2201 if (hs->key_share_bytes == NULL) { 2202 return 0; 2203 } 2204 } 2205 2206 return CBB_flush(out); 2207 } 2208 2209 int ssl_ext_key_share_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t **out_secret, 2210 size_t *out_secret_len, 2211 uint8_t *out_alert, CBS *contents) { 2212 CBS peer_key; 2213 uint16_t group_id; 2214 if (!CBS_get_u16(contents, &group_id) || 2215 !CBS_get_u16_length_prefixed(contents, &peer_key) || 2216 CBS_len(contents) != 0) { 2217 *out_alert = SSL_AD_DECODE_ERROR; 2218 return 0; 2219 } 2220 2221 if (SSL_ECDH_CTX_get_id(&hs->ecdh_ctx) != group_id) { 2222 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 2223 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CURVE); 2224 return 0; 2225 } 2226 2227 if (!SSL_ECDH_CTX_finish(&hs->ecdh_ctx, out_secret, out_secret_len, out_alert, 2228 CBS_data(&peer_key), CBS_len(&peer_key))) { 2229 *out_alert = SSL_AD_INTERNAL_ERROR; 2230 return 0; 2231 } 2232 2233 hs->new_session->group_id = group_id; 2234 SSL_ECDH_CTX_cleanup(&hs->ecdh_ctx); 2235 return 1; 2236 } 2237 2238 int ssl_ext_key_share_parse_clienthello(SSL_HANDSHAKE *hs, int *out_found, 2239 uint8_t **out_secret, 2240 size_t *out_secret_len, 2241 uint8_t *out_alert, CBS *contents) { 2242 uint16_t group_id; 2243 CBS key_shares; 2244 if (!tls1_get_shared_group(hs, &group_id)) { 2245 OPENSSL_PUT_ERROR(SSL, SSL_R_NO_SHARED_GROUP); 2246 *out_alert = SSL_AD_HANDSHAKE_FAILURE; 2247 return 0; 2248 } 2249 2250 if (!CBS_get_u16_length_prefixed(contents, &key_shares) || 2251 CBS_len(contents) != 0) { 2252 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 2253 return 0; 2254 } 2255 2256 /* Find the corresponding key share. */ 2257 int found = 0; 2258 CBS peer_key; 2259 while (CBS_len(&key_shares) > 0) { 2260 uint16_t id; 2261 CBS peer_key_tmp; 2262 if (!CBS_get_u16(&key_shares, &id) || 2263 !CBS_get_u16_length_prefixed(&key_shares, &peer_key_tmp)) { 2264 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 2265 return 0; 2266 } 2267 2268 if (id == group_id) { 2269 if (found) { 2270 OPENSSL_PUT_ERROR(SSL, SSL_R_DUPLICATE_KEY_SHARE); 2271 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 2272 return 0; 2273 } 2274 2275 found = 1; 2276 peer_key = peer_key_tmp; 2277 /* Continue parsing the structure to keep peers honest. */ 2278 } 2279 } 2280 2281 if (!found) { 2282 *out_found = 0; 2283 *out_secret = NULL; 2284 *out_secret_len = 0; 2285 return 1; 2286 } 2287 2288 /* Compute the DH secret. */ 2289 uint8_t *secret = NULL; 2290 size_t secret_len; 2291 SSL_ECDH_CTX group; 2292 OPENSSL_memset(&group, 0, sizeof(SSL_ECDH_CTX)); 2293 CBB public_key; 2294 if (!CBB_init(&public_key, 32) || 2295 !SSL_ECDH_CTX_init(&group, group_id) || 2296 !SSL_ECDH_CTX_accept(&group, &public_key, &secret, &secret_len, out_alert, 2297 CBS_data(&peer_key), CBS_len(&peer_key)) || 2298 !CBB_finish(&public_key, &hs->ecdh_public_key, 2299 &hs->ecdh_public_key_len)) { 2300 OPENSSL_free(secret); 2301 SSL_ECDH_CTX_cleanup(&group); 2302 CBB_cleanup(&public_key); 2303 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 2304 return 0; 2305 } 2306 2307 SSL_ECDH_CTX_cleanup(&group); 2308 2309 *out_secret = secret; 2310 *out_secret_len = secret_len; 2311 *out_found = 1; 2312 return 1; 2313 } 2314 2315 int ssl_ext_key_share_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 2316 uint16_t group_id; 2317 CBB kse_bytes, public_key; 2318 if (!tls1_get_shared_group(hs, &group_id) || 2319 !CBB_add_u16(out, TLSEXT_TYPE_key_share) || 2320 !CBB_add_u16_length_prefixed(out, &kse_bytes) || 2321 !CBB_add_u16(&kse_bytes, group_id) || 2322 !CBB_add_u16_length_prefixed(&kse_bytes, &public_key) || 2323 !CBB_add_bytes(&public_key, hs->ecdh_public_key, 2324 hs->ecdh_public_key_len) || 2325 !CBB_flush(out)) { 2326 return 0; 2327 } 2328 2329 OPENSSL_free(hs->ecdh_public_key); 2330 hs->ecdh_public_key = NULL; 2331 hs->ecdh_public_key_len = 0; 2332 2333 hs->new_session->group_id = group_id; 2334 return 1; 2335 } 2336 2337 2338 /* Supported Versions 2339 * 2340 * https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.1 */ 2341 2342 static int ext_supported_versions_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 2343 SSL *const ssl = hs->ssl; 2344 if (hs->max_version <= TLS1_2_VERSION) { 2345 return 1; 2346 } 2347 2348 CBB contents, versions; 2349 if (!CBB_add_u16(out, TLSEXT_TYPE_supported_versions) || 2350 !CBB_add_u16_length_prefixed(out, &contents) || 2351 !CBB_add_u8_length_prefixed(&contents, &versions)) { 2352 return 0; 2353 } 2354 2355 /* Add a fake version. See draft-davidben-tls-grease-01. */ 2356 if (ssl->ctx->grease_enabled && 2357 !CBB_add_u16(&versions, ssl_get_grease_value(ssl, ssl_grease_version))) { 2358 return 0; 2359 } 2360 2361 if (!ssl_add_supported_versions(hs, &versions) || 2362 !CBB_flush(out)) { 2363 return 0; 2364 } 2365 2366 return 1; 2367 } 2368 2369 2370 /* Cookie 2371 * 2372 * https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.2 */ 2373 2374 static int ext_cookie_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 2375 if (hs->cookie == NULL) { 2376 return 1; 2377 } 2378 2379 CBB contents, cookie; 2380 if (!CBB_add_u16(out, TLSEXT_TYPE_cookie) || 2381 !CBB_add_u16_length_prefixed(out, &contents) || 2382 !CBB_add_u16_length_prefixed(&contents, &cookie) || 2383 !CBB_add_bytes(&cookie, hs->cookie, hs->cookie_len) || 2384 !CBB_flush(out)) { 2385 return 0; 2386 } 2387 2388 /* The cookie is no longer needed in memory. */ 2389 OPENSSL_free(hs->cookie); 2390 hs->cookie = NULL; 2391 hs->cookie_len = 0; 2392 return 1; 2393 } 2394 2395 2396 /* Negotiated Groups 2397 * 2398 * https://tools.ietf.org/html/rfc4492#section-5.1.2 2399 * https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.4 */ 2400 2401 static int ext_supported_groups_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) { 2402 SSL *const ssl = hs->ssl; 2403 CBB contents, groups_bytes; 2404 if (!CBB_add_u16(out, TLSEXT_TYPE_supported_groups) || 2405 !CBB_add_u16_length_prefixed(out, &contents) || 2406 !CBB_add_u16_length_prefixed(&contents, &groups_bytes)) { 2407 return 0; 2408 } 2409 2410 /* Add a fake group. See draft-davidben-tls-grease-01. */ 2411 if (ssl->ctx->grease_enabled && 2412 !CBB_add_u16(&groups_bytes, 2413 ssl_get_grease_value(ssl, ssl_grease_group))) { 2414 return 0; 2415 } 2416 2417 const uint16_t *groups; 2418 size_t groups_len; 2419 tls1_get_grouplist(ssl, &groups, &groups_len); 2420 2421 for (size_t i = 0; i < groups_len; i++) { 2422 if (!CBB_add_u16(&groups_bytes, groups[i])) { 2423 return 0; 2424 } 2425 } 2426 2427 return CBB_flush(out); 2428 } 2429 2430 static int ext_supported_groups_parse_serverhello(SSL_HANDSHAKE *hs, 2431 uint8_t *out_alert, 2432 CBS *contents) { 2433 /* This extension is not expected to be echoed by servers in TLS 1.2, but some 2434 * BigIP servers send it nonetheless, so do not enforce this. */ 2435 return 1; 2436 } 2437 2438 static int ext_supported_groups_parse_clienthello(SSL_HANDSHAKE *hs, 2439 uint8_t *out_alert, 2440 CBS *contents) { 2441 if (contents == NULL) { 2442 return 1; 2443 } 2444 2445 CBS supported_group_list; 2446 if (!CBS_get_u16_length_prefixed(contents, &supported_group_list) || 2447 CBS_len(&supported_group_list) == 0 || 2448 (CBS_len(&supported_group_list) & 1) != 0 || 2449 CBS_len(contents) != 0) { 2450 return 0; 2451 } 2452 2453 hs->peer_supported_group_list = 2454 (uint16_t *)OPENSSL_malloc(CBS_len(&supported_group_list)); 2455 if (hs->peer_supported_group_list == NULL) { 2456 *out_alert = SSL_AD_INTERNAL_ERROR; 2457 return 0; 2458 } 2459 2460 const size_t num_groups = CBS_len(&supported_group_list) / 2; 2461 for (size_t i = 0; i < num_groups; i++) { 2462 if (!CBS_get_u16(&supported_group_list, 2463 &hs->peer_supported_group_list[i])) { 2464 goto err; 2465 } 2466 } 2467 2468 assert(CBS_len(&supported_group_list) == 0); 2469 hs->peer_supported_group_list_len = num_groups; 2470 2471 return 1; 2472 2473 err: 2474 OPENSSL_free(hs->peer_supported_group_list); 2475 hs->peer_supported_group_list = NULL; 2476 *out_alert = SSL_AD_INTERNAL_ERROR; 2477 return 0; 2478 } 2479 2480 static int ext_supported_groups_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) { 2481 /* Servers don't echo this extension. */ 2482 return 1; 2483 } 2484 2485 2486 /* kExtensions contains all the supported extensions. */ 2487 static const struct tls_extension kExtensions[] = { 2488 { 2489 TLSEXT_TYPE_renegotiate, 2490 NULL, 2491 ext_ri_add_clienthello, 2492 ext_ri_parse_serverhello, 2493 ext_ri_parse_clienthello, 2494 ext_ri_add_serverhello, 2495 }, 2496 { 2497 TLSEXT_TYPE_server_name, 2498 NULL, 2499 ext_sni_add_clienthello, 2500 ext_sni_parse_serverhello, 2501 ext_sni_parse_clienthello, 2502 ext_sni_add_serverhello, 2503 }, 2504 { 2505 TLSEXT_TYPE_extended_master_secret, 2506 NULL, 2507 ext_ems_add_clienthello, 2508 ext_ems_parse_serverhello, 2509 ext_ems_parse_clienthello, 2510 ext_ems_add_serverhello, 2511 }, 2512 { 2513 TLSEXT_TYPE_session_ticket, 2514 NULL, 2515 ext_ticket_add_clienthello, 2516 ext_ticket_parse_serverhello, 2517 /* Ticket extension client parsing is handled in ssl_session.c */ 2518 ignore_parse_clienthello, 2519 ext_ticket_add_serverhello, 2520 }, 2521 { 2522 TLSEXT_TYPE_signature_algorithms, 2523 NULL, 2524 ext_sigalgs_add_clienthello, 2525 forbid_parse_serverhello, 2526 ext_sigalgs_parse_clienthello, 2527 dont_add_serverhello, 2528 }, 2529 { 2530 TLSEXT_TYPE_status_request, 2531 NULL, 2532 ext_ocsp_add_clienthello, 2533 ext_ocsp_parse_serverhello, 2534 ext_ocsp_parse_clienthello, 2535 ext_ocsp_add_serverhello, 2536 }, 2537 { 2538 TLSEXT_TYPE_next_proto_neg, 2539 NULL, 2540 ext_npn_add_clienthello, 2541 ext_npn_parse_serverhello, 2542 ext_npn_parse_clienthello, 2543 ext_npn_add_serverhello, 2544 }, 2545 { 2546 TLSEXT_TYPE_certificate_timestamp, 2547 NULL, 2548 ext_sct_add_clienthello, 2549 ext_sct_parse_serverhello, 2550 ext_sct_parse_clienthello, 2551 ext_sct_add_serverhello, 2552 }, 2553 { 2554 TLSEXT_TYPE_application_layer_protocol_negotiation, 2555 NULL, 2556 ext_alpn_add_clienthello, 2557 ext_alpn_parse_serverhello, 2558 /* ALPN is negotiated late in |ssl_negotiate_alpn|. */ 2559 ignore_parse_clienthello, 2560 ext_alpn_add_serverhello, 2561 }, 2562 { 2563 TLSEXT_TYPE_channel_id, 2564 ext_channel_id_init, 2565 ext_channel_id_add_clienthello, 2566 ext_channel_id_parse_serverhello, 2567 ext_channel_id_parse_clienthello, 2568 ext_channel_id_add_serverhello, 2569 }, 2570 { 2571 TLSEXT_TYPE_srtp, 2572 ext_srtp_init, 2573 ext_srtp_add_clienthello, 2574 ext_srtp_parse_serverhello, 2575 ext_srtp_parse_clienthello, 2576 ext_srtp_add_serverhello, 2577 }, 2578 { 2579 TLSEXT_TYPE_ec_point_formats, 2580 NULL, 2581 ext_ec_point_add_clienthello, 2582 ext_ec_point_parse_serverhello, 2583 ext_ec_point_parse_clienthello, 2584 ext_ec_point_add_serverhello, 2585 }, 2586 { 2587 TLSEXT_TYPE_key_share, 2588 NULL, 2589 ext_key_share_add_clienthello, 2590 forbid_parse_serverhello, 2591 ignore_parse_clienthello, 2592 dont_add_serverhello, 2593 }, 2594 { 2595 TLSEXT_TYPE_psk_key_exchange_modes, 2596 NULL, 2597 ext_psk_key_exchange_modes_add_clienthello, 2598 forbid_parse_serverhello, 2599 ext_psk_key_exchange_modes_parse_clienthello, 2600 dont_add_serverhello, 2601 }, 2602 { 2603 TLSEXT_TYPE_early_data, 2604 NULL, 2605 ext_early_data_add_clienthello, 2606 ext_early_data_parse_serverhello, 2607 ext_early_data_parse_clienthello, 2608 ext_early_data_add_serverhello, 2609 }, 2610 { 2611 TLSEXT_TYPE_supported_versions, 2612 NULL, 2613 ext_supported_versions_add_clienthello, 2614 forbid_parse_serverhello, 2615 ignore_parse_clienthello, 2616 dont_add_serverhello, 2617 }, 2618 { 2619 TLSEXT_TYPE_cookie, 2620 NULL, 2621 ext_cookie_add_clienthello, 2622 forbid_parse_serverhello, 2623 ignore_parse_clienthello, 2624 dont_add_serverhello, 2625 }, 2626 /* The final extension must be non-empty. WebSphere Application Server 7.0 is 2627 * intolerant to the last extension being zero-length. See 2628 * https://crbug.com/363583. */ 2629 { 2630 TLSEXT_TYPE_supported_groups, 2631 NULL, 2632 ext_supported_groups_add_clienthello, 2633 ext_supported_groups_parse_serverhello, 2634 ext_supported_groups_parse_clienthello, 2635 ext_supported_groups_add_serverhello, 2636 }, 2637 }; 2638 2639 #define kNumExtensions (sizeof(kExtensions) / sizeof(struct tls_extension)) 2640 2641 static_assert(kNumExtensions <= 2642 sizeof(((SSL_HANDSHAKE *)NULL)->extensions.sent) * 8, 2643 "too many extensions for sent bitset"); 2644 static_assert(kNumExtensions <= 2645 sizeof(((SSL_HANDSHAKE *)NULL)->extensions.received) * 8, 2646 "too many extensions for received bitset"); 2647 2648 static const struct tls_extension *tls_extension_find(uint32_t *out_index, 2649 uint16_t value) { 2650 unsigned i; 2651 for (i = 0; i < kNumExtensions; i++) { 2652 if (kExtensions[i].value == value) { 2653 *out_index = i; 2654 return &kExtensions[i]; 2655 } 2656 } 2657 2658 return NULL; 2659 } 2660 2661 int SSL_extension_supported(unsigned extension_value) { 2662 uint32_t index; 2663 return extension_value == TLSEXT_TYPE_padding || 2664 tls_extension_find(&index, extension_value) != NULL; 2665 } 2666 2667 int ssl_add_clienthello_tlsext(SSL_HANDSHAKE *hs, CBB *out, size_t header_len) { 2668 SSL *const ssl = hs->ssl; 2669 /* Don't add extensions for SSLv3 unless doing secure renegotiation. */ 2670 if (hs->client_version == SSL3_VERSION && 2671 !ssl->s3->send_connection_binding) { 2672 return 1; 2673 } 2674 2675 CBB extensions; 2676 if (!CBB_add_u16_length_prefixed(out, &extensions)) { 2677 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 2678 return 0; 2679 } 2680 2681 hs->extensions.sent = 0; 2682 hs->custom_extensions.sent = 0; 2683 2684 for (size_t i = 0; i < kNumExtensions; i++) { 2685 if (kExtensions[i].init != NULL) { 2686 kExtensions[i].init(hs); 2687 } 2688 } 2689 2690 uint16_t grease_ext1 = 0; 2691 if (ssl->ctx->grease_enabled) { 2692 /* Add a fake empty extension. See draft-davidben-tls-grease-01. */ 2693 grease_ext1 = ssl_get_grease_value(ssl, ssl_grease_extension1); 2694 if (!CBB_add_u16(&extensions, grease_ext1) || 2695 !CBB_add_u16(&extensions, 0 /* zero length */)) { 2696 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 2697 return 0; 2698 } 2699 } 2700 2701 for (size_t i = 0; i < kNumExtensions; i++) { 2702 const size_t len_before = CBB_len(&extensions); 2703 if (!kExtensions[i].add_clienthello(hs, &extensions)) { 2704 OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_ADDING_EXTENSION); 2705 ERR_add_error_dataf("extension %u", (unsigned)kExtensions[i].value); 2706 return 0; 2707 } 2708 2709 if (CBB_len(&extensions) != len_before) { 2710 hs->extensions.sent |= (1u << i); 2711 } 2712 } 2713 2714 if (!custom_ext_add_clienthello(hs, &extensions)) { 2715 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 2716 return 0; 2717 } 2718 2719 if (ssl->ctx->grease_enabled) { 2720 /* Add a fake non-empty extension. See draft-davidben-tls-grease-01. */ 2721 uint16_t grease_ext2 = ssl_get_grease_value(ssl, ssl_grease_extension2); 2722 2723 /* The two fake extensions must not have the same value. GREASE values are 2724 * of the form 0x1a1a, 0x2a2a, 0x3a3a, etc., so XOR to generate a different 2725 * one. */ 2726 if (grease_ext1 == grease_ext2) { 2727 grease_ext2 ^= 0x1010; 2728 } 2729 2730 if (!CBB_add_u16(&extensions, grease_ext2) || 2731 !CBB_add_u16(&extensions, 1 /* one byte length */) || 2732 !CBB_add_u8(&extensions, 0 /* single zero byte as contents */)) { 2733 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 2734 return 0; 2735 } 2736 } 2737 2738 if (!SSL_is_dtls(ssl)) { 2739 size_t psk_extension_len = ext_pre_shared_key_clienthello_length(hs); 2740 header_len += 2 + CBB_len(&extensions) + psk_extension_len; 2741 if (header_len > 0xff && header_len < 0x200) { 2742 /* Add padding to workaround bugs in F5 terminators. See RFC 7685. 2743 * 2744 * NB: because this code works out the length of all existing extensions 2745 * it MUST always appear last. */ 2746 size_t padding_len = 0x200 - header_len; 2747 /* Extensions take at least four bytes to encode. Always include at least 2748 * one byte of data if including the extension. WebSphere Application 2749 * Server 7.0 is intolerant to the last extension being zero-length. See 2750 * https://crbug.com/363583. */ 2751 if (padding_len >= 4 + 1) { 2752 padding_len -= 4; 2753 } else { 2754 padding_len = 1; 2755 } 2756 2757 uint8_t *padding_bytes; 2758 if (!CBB_add_u16(&extensions, TLSEXT_TYPE_padding) || 2759 !CBB_add_u16(&extensions, padding_len) || 2760 !CBB_add_space(&extensions, &padding_bytes, padding_len)) { 2761 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 2762 return 0; 2763 } 2764 2765 OPENSSL_memset(padding_bytes, 0, padding_len); 2766 } 2767 } 2768 2769 /* The PSK extension must be last, including after the padding. */ 2770 if (!ext_pre_shared_key_add_clienthello(hs, &extensions)) { 2771 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 2772 return 0; 2773 } 2774 2775 /* Discard empty extensions blocks. */ 2776 if (CBB_len(&extensions) == 0) { 2777 CBB_discard_child(out); 2778 } 2779 2780 return CBB_flush(out); 2781 } 2782 2783 int ssl_add_serverhello_tlsext(SSL_HANDSHAKE *hs, CBB *out) { 2784 SSL *const ssl = hs->ssl; 2785 CBB extensions; 2786 if (!CBB_add_u16_length_prefixed(out, &extensions)) { 2787 goto err; 2788 } 2789 2790 for (unsigned i = 0; i < kNumExtensions; i++) { 2791 if (!(hs->extensions.received & (1u << i))) { 2792 /* Don't send extensions that were not received. */ 2793 continue; 2794 } 2795 2796 if (!kExtensions[i].add_serverhello(hs, &extensions)) { 2797 OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_ADDING_EXTENSION); 2798 ERR_add_error_dataf("extension %u", (unsigned)kExtensions[i].value); 2799 goto err; 2800 } 2801 } 2802 2803 if (!custom_ext_add_serverhello(hs, &extensions)) { 2804 goto err; 2805 } 2806 2807 /* Discard empty extensions blocks before TLS 1.3. */ 2808 if (ssl3_protocol_version(ssl) < TLS1_3_VERSION && 2809 CBB_len(&extensions) == 0) { 2810 CBB_discard_child(out); 2811 } 2812 2813 return CBB_flush(out); 2814 2815 err: 2816 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 2817 return 0; 2818 } 2819 2820 static int ssl_scan_clienthello_tlsext(SSL_HANDSHAKE *hs, 2821 const SSL_CLIENT_HELLO *client_hello, 2822 int *out_alert) { 2823 SSL *const ssl = hs->ssl; 2824 for (size_t i = 0; i < kNumExtensions; i++) { 2825 if (kExtensions[i].init != NULL) { 2826 kExtensions[i].init(hs); 2827 } 2828 } 2829 2830 hs->extensions.received = 0; 2831 hs->custom_extensions.received = 0; 2832 2833 CBS extensions; 2834 CBS_init(&extensions, client_hello->extensions, client_hello->extensions_len); 2835 while (CBS_len(&extensions) != 0) { 2836 uint16_t type; 2837 CBS extension; 2838 2839 /* Decode the next extension. */ 2840 if (!CBS_get_u16(&extensions, &type) || 2841 !CBS_get_u16_length_prefixed(&extensions, &extension)) { 2842 *out_alert = SSL_AD_DECODE_ERROR; 2843 return 0; 2844 } 2845 2846 /* RFC 5746 made the existence of extensions in SSL 3.0 somewhat 2847 * ambiguous. Ignore all but the renegotiation_info extension. */ 2848 if (ssl->version == SSL3_VERSION && type != TLSEXT_TYPE_renegotiate) { 2849 continue; 2850 } 2851 2852 unsigned ext_index; 2853 const struct tls_extension *const ext = 2854 tls_extension_find(&ext_index, type); 2855 2856 if (ext == NULL) { 2857 if (!custom_ext_parse_clienthello(hs, out_alert, type, &extension)) { 2858 OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_PARSING_EXTENSION); 2859 return 0; 2860 } 2861 continue; 2862 } 2863 2864 hs->extensions.received |= (1u << ext_index); 2865 uint8_t alert = SSL_AD_DECODE_ERROR; 2866 if (!ext->parse_clienthello(hs, &alert, &extension)) { 2867 *out_alert = alert; 2868 OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_PARSING_EXTENSION); 2869 ERR_add_error_dataf("extension %u", (unsigned)type); 2870 return 0; 2871 } 2872 } 2873 2874 for (size_t i = 0; i < kNumExtensions; i++) { 2875 if (hs->extensions.received & (1u << i)) { 2876 continue; 2877 } 2878 2879 CBS *contents = NULL, fake_contents; 2880 static const uint8_t kFakeRenegotiateExtension[] = {0}; 2881 if (kExtensions[i].value == TLSEXT_TYPE_renegotiate && 2882 ssl_client_cipher_list_contains_cipher(client_hello, 2883 SSL3_CK_SCSV & 0xffff)) { 2884 /* The renegotiation SCSV was received so pretend that we received a 2885 * renegotiation extension. */ 2886 CBS_init(&fake_contents, kFakeRenegotiateExtension, 2887 sizeof(kFakeRenegotiateExtension)); 2888 contents = &fake_contents; 2889 hs->extensions.received |= (1u << i); 2890 } 2891 2892 /* Extension wasn't observed so call the callback with a NULL 2893 * parameter. */ 2894 uint8_t alert = SSL_AD_DECODE_ERROR; 2895 if (!kExtensions[i].parse_clienthello(hs, &alert, contents)) { 2896 OPENSSL_PUT_ERROR(SSL, SSL_R_MISSING_EXTENSION); 2897 ERR_add_error_dataf("extension %u", (unsigned)kExtensions[i].value); 2898 *out_alert = alert; 2899 return 0; 2900 } 2901 } 2902 2903 return 1; 2904 } 2905 2906 int ssl_parse_clienthello_tlsext(SSL_HANDSHAKE *hs, 2907 const SSL_CLIENT_HELLO *client_hello) { 2908 SSL *const ssl = hs->ssl; 2909 int alert = SSL_AD_DECODE_ERROR; 2910 if (ssl_scan_clienthello_tlsext(hs, client_hello, &alert) <= 0) { 2911 ssl3_send_alert(ssl, SSL3_AL_FATAL, alert); 2912 return 0; 2913 } 2914 2915 if (ssl_check_clienthello_tlsext(hs) <= 0) { 2916 OPENSSL_PUT_ERROR(SSL, SSL_R_CLIENTHELLO_TLSEXT); 2917 return 0; 2918 } 2919 2920 return 1; 2921 } 2922 2923 static int ssl_scan_serverhello_tlsext(SSL_HANDSHAKE *hs, CBS *cbs, 2924 int *out_alert) { 2925 SSL *const ssl = hs->ssl; 2926 /* Before TLS 1.3, ServerHello extensions blocks may be omitted if empty. */ 2927 if (CBS_len(cbs) == 0 && ssl3_protocol_version(ssl) < TLS1_3_VERSION) { 2928 return 1; 2929 } 2930 2931 /* Decode the extensions block and check it is valid. */ 2932 CBS extensions; 2933 if (!CBS_get_u16_length_prefixed(cbs, &extensions) || 2934 !tls1_check_duplicate_extensions(&extensions)) { 2935 *out_alert = SSL_AD_DECODE_ERROR; 2936 return 0; 2937 } 2938 2939 uint32_t received = 0; 2940 while (CBS_len(&extensions) != 0) { 2941 uint16_t type; 2942 CBS extension; 2943 2944 /* Decode the next extension. */ 2945 if (!CBS_get_u16(&extensions, &type) || 2946 !CBS_get_u16_length_prefixed(&extensions, &extension)) { 2947 *out_alert = SSL_AD_DECODE_ERROR; 2948 return 0; 2949 } 2950 2951 unsigned ext_index; 2952 const struct tls_extension *const ext = 2953 tls_extension_find(&ext_index, type); 2954 2955 if (ext == NULL) { 2956 if (!custom_ext_parse_serverhello(hs, out_alert, type, &extension)) { 2957 return 0; 2958 } 2959 continue; 2960 } 2961 2962 static_assert(kNumExtensions <= sizeof(hs->extensions.sent) * 8, 2963 "too many bits"); 2964 2965 if (!(hs->extensions.sent & (1u << ext_index)) && 2966 type != TLSEXT_TYPE_renegotiate) { 2967 /* If the extension was never sent then it is illegal, except for the 2968 * renegotiation extension which, in SSL 3.0, is signaled via SCSV. */ 2969 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION); 2970 ERR_add_error_dataf("extension :%u", (unsigned)type); 2971 *out_alert = SSL_AD_UNSUPPORTED_EXTENSION; 2972 return 0; 2973 } 2974 2975 received |= (1u << ext_index); 2976 2977 uint8_t alert = SSL_AD_DECODE_ERROR; 2978 if (!ext->parse_serverhello(hs, &alert, &extension)) { 2979 OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_PARSING_EXTENSION); 2980 ERR_add_error_dataf("extension %u", (unsigned)type); 2981 *out_alert = alert; 2982 return 0; 2983 } 2984 } 2985 2986 for (size_t i = 0; i < kNumExtensions; i++) { 2987 if (!(received & (1u << i))) { 2988 /* Extension wasn't observed so call the callback with a NULL 2989 * parameter. */ 2990 uint8_t alert = SSL_AD_DECODE_ERROR; 2991 if (!kExtensions[i].parse_serverhello(hs, &alert, NULL)) { 2992 OPENSSL_PUT_ERROR(SSL, SSL_R_MISSING_EXTENSION); 2993 ERR_add_error_dataf("extension %u", (unsigned)kExtensions[i].value); 2994 *out_alert = alert; 2995 return 0; 2996 } 2997 } 2998 } 2999 3000 return 1; 3001 } 3002 3003 static int ssl_check_clienthello_tlsext(SSL_HANDSHAKE *hs) { 3004 SSL *const ssl = hs->ssl; 3005 int ret = SSL_TLSEXT_ERR_NOACK; 3006 int al = SSL_AD_UNRECOGNIZED_NAME; 3007 3008 if (ssl->ctx->tlsext_servername_callback != 0) { 3009 ret = ssl->ctx->tlsext_servername_callback(ssl, &al, 3010 ssl->ctx->tlsext_servername_arg); 3011 } else if (ssl->session_ctx->tlsext_servername_callback != 0) { 3012 ret = ssl->session_ctx->tlsext_servername_callback( 3013 ssl, &al, ssl->session_ctx->tlsext_servername_arg); 3014 } 3015 3016 switch (ret) { 3017 case SSL_TLSEXT_ERR_ALERT_FATAL: 3018 ssl3_send_alert(ssl, SSL3_AL_FATAL, al); 3019 return -1; 3020 3021 case SSL_TLSEXT_ERR_NOACK: 3022 hs->should_ack_sni = 0; 3023 return 1; 3024 3025 default: 3026 return 1; 3027 } 3028 } 3029 3030 int ssl_parse_serverhello_tlsext(SSL_HANDSHAKE *hs, CBS *cbs) { 3031 SSL *const ssl = hs->ssl; 3032 int alert = SSL_AD_DECODE_ERROR; 3033 if (ssl_scan_serverhello_tlsext(hs, cbs, &alert) <= 0) { 3034 ssl3_send_alert(ssl, SSL3_AL_FATAL, alert); 3035 return 0; 3036 } 3037 3038 return 1; 3039 } 3040 3041 static enum ssl_ticket_aead_result_t 3042 ssl_decrypt_ticket_with_cipher_ctx(SSL *ssl, uint8_t **out, size_t *out_len, 3043 int *out_renew_ticket, const uint8_t *ticket, 3044 size_t ticket_len) { 3045 const SSL_CTX *const ssl_ctx = ssl->session_ctx; 3046 3047 bssl::ScopedHMAC_CTX hmac_ctx; 3048 bssl::ScopedEVP_CIPHER_CTX cipher_ctx; 3049 3050 /* Ensure there is room for the key name and the largest IV 3051 * |tlsext_ticket_key_cb| may try to consume. The real limit may be lower, but 3052 * the maximum IV length should be well under the minimum size for the 3053 * session material and HMAC. */ 3054 if (ticket_len < SSL_TICKET_KEY_NAME_LEN + EVP_MAX_IV_LENGTH) { 3055 return ssl_ticket_aead_ignore_ticket; 3056 } 3057 const uint8_t *iv = ticket + SSL_TICKET_KEY_NAME_LEN; 3058 3059 if (ssl_ctx->tlsext_ticket_key_cb != NULL) { 3060 int cb_ret = ssl_ctx->tlsext_ticket_key_cb( 3061 ssl, (uint8_t *)ticket /* name */, (uint8_t *)iv, cipher_ctx.get(), 3062 hmac_ctx.get(), 0 /* decrypt */); 3063 if (cb_ret < 0) { 3064 return ssl_ticket_aead_error; 3065 } else if (cb_ret == 0) { 3066 return ssl_ticket_aead_ignore_ticket; 3067 } else if (cb_ret == 2) { 3068 *out_renew_ticket = 1; 3069 } 3070 } else { 3071 /* Check the key name matches. */ 3072 if (OPENSSL_memcmp(ticket, ssl_ctx->tlsext_tick_key_name, 3073 SSL_TICKET_KEY_NAME_LEN) != 0) { 3074 return ssl_ticket_aead_ignore_ticket; 3075 } 3076 if (!HMAC_Init_ex(hmac_ctx.get(), ssl_ctx->tlsext_tick_hmac_key, 3077 sizeof(ssl_ctx->tlsext_tick_hmac_key), tlsext_tick_md(), 3078 NULL) || 3079 !EVP_DecryptInit_ex(cipher_ctx.get(), EVP_aes_128_cbc(), NULL, 3080 ssl_ctx->tlsext_tick_aes_key, iv)) { 3081 return ssl_ticket_aead_error; 3082 } 3083 } 3084 size_t iv_len = EVP_CIPHER_CTX_iv_length(cipher_ctx.get()); 3085 3086 /* Check the MAC at the end of the ticket. */ 3087 uint8_t mac[EVP_MAX_MD_SIZE]; 3088 size_t mac_len = HMAC_size(hmac_ctx.get()); 3089 if (ticket_len < SSL_TICKET_KEY_NAME_LEN + iv_len + 1 + mac_len) { 3090 /* The ticket must be large enough for key name, IV, data, and MAC. */ 3091 return ssl_ticket_aead_ignore_ticket; 3092 } 3093 HMAC_Update(hmac_ctx.get(), ticket, ticket_len - mac_len); 3094 HMAC_Final(hmac_ctx.get(), mac, NULL); 3095 int mac_ok = 3096 CRYPTO_memcmp(mac, ticket + (ticket_len - mac_len), mac_len) == 0; 3097 #if defined(BORINGSSL_UNSAFE_FUZZER_MODE) 3098 mac_ok = 1; 3099 #endif 3100 if (!mac_ok) { 3101 return ssl_ticket_aead_ignore_ticket; 3102 } 3103 3104 /* Decrypt the session data. */ 3105 const uint8_t *ciphertext = ticket + SSL_TICKET_KEY_NAME_LEN + iv_len; 3106 size_t ciphertext_len = ticket_len - SSL_TICKET_KEY_NAME_LEN - iv_len - 3107 mac_len; 3108 bssl::UniquePtr<uint8_t> plaintext((uint8_t *)OPENSSL_malloc(ciphertext_len)); 3109 if (!plaintext) { 3110 return ssl_ticket_aead_error; 3111 } 3112 size_t plaintext_len; 3113 #if defined(BORINGSSL_UNSAFE_FUZZER_MODE) 3114 OPENSSL_memcpy(plaintext.get(), ciphertext, ciphertext_len); 3115 plaintext_len = ciphertext_len; 3116 #else 3117 if (ciphertext_len >= INT_MAX) { 3118 return ssl_ticket_aead_ignore_ticket; 3119 } 3120 int len1, len2; 3121 if (!EVP_DecryptUpdate(cipher_ctx.get(), plaintext.get(), &len1, ciphertext, 3122 (int)ciphertext_len) || 3123 !EVP_DecryptFinal_ex(cipher_ctx.get(), plaintext.get() + len1, &len2)) { 3124 ERR_clear_error(); 3125 return ssl_ticket_aead_ignore_ticket; 3126 } 3127 plaintext_len = (size_t)(len1) + len2; 3128 #endif 3129 3130 *out = plaintext.release(); 3131 *out_len = plaintext_len; 3132 return ssl_ticket_aead_success; 3133 } 3134 3135 static enum ssl_ticket_aead_result_t ssl_decrypt_ticket_with_method( 3136 SSL *ssl, uint8_t **out, size_t *out_len, int *out_renew_ticket, 3137 const uint8_t *ticket, size_t ticket_len) { 3138 uint8_t *plaintext = (uint8_t *)OPENSSL_malloc(ticket_len); 3139 if (plaintext == NULL) { 3140 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); 3141 return ssl_ticket_aead_error; 3142 } 3143 3144 size_t plaintext_len; 3145 const enum ssl_ticket_aead_result_t result = 3146 ssl->session_ctx->ticket_aead_method->open( 3147 ssl, plaintext, &plaintext_len, ticket_len, ticket, ticket_len); 3148 3149 if (result == ssl_ticket_aead_success) { 3150 *out = plaintext; 3151 plaintext = NULL; 3152 *out_len = plaintext_len; 3153 } 3154 3155 OPENSSL_free(plaintext); 3156 return result; 3157 } 3158 3159 enum ssl_ticket_aead_result_t ssl_process_ticket( 3160 SSL *ssl, SSL_SESSION **out_session, int *out_renew_ticket, 3161 const uint8_t *ticket, size_t ticket_len, const uint8_t *session_id, 3162 size_t session_id_len) { 3163 *out_renew_ticket = 0; 3164 *out_session = NULL; 3165 3166 if ((SSL_get_options(ssl) & SSL_OP_NO_TICKET) || 3167 session_id_len > SSL_MAX_SSL_SESSION_ID_LENGTH) { 3168 return ssl_ticket_aead_ignore_ticket; 3169 } 3170 3171 uint8_t *plaintext = NULL; 3172 size_t plaintext_len; 3173 enum ssl_ticket_aead_result_t result; 3174 if (ssl->session_ctx->ticket_aead_method != NULL) { 3175 result = ssl_decrypt_ticket_with_method( 3176 ssl, &plaintext, &plaintext_len, out_renew_ticket, ticket, ticket_len); 3177 } else { 3178 result = ssl_decrypt_ticket_with_cipher_ctx( 3179 ssl, &plaintext, &plaintext_len, out_renew_ticket, ticket, ticket_len); 3180 } 3181 3182 if (result != ssl_ticket_aead_success) { 3183 return result; 3184 } 3185 3186 /* Decode the session. */ 3187 SSL_SESSION *session = 3188 SSL_SESSION_from_bytes(plaintext, plaintext_len, ssl->ctx); 3189 OPENSSL_free(plaintext); 3190 3191 if (session == NULL) { 3192 ERR_clear_error(); /* Don't leave an error on the queue. */ 3193 return ssl_ticket_aead_ignore_ticket; 3194 } 3195 3196 /* Copy the client's session ID into the new session, to denote the ticket has 3197 * been accepted. */ 3198 OPENSSL_memcpy(session->session_id, session_id, session_id_len); 3199 session->session_id_length = session_id_len; 3200 3201 *out_session = session; 3202 return ssl_ticket_aead_success; 3203 } 3204 3205 int tls1_parse_peer_sigalgs(SSL_HANDSHAKE *hs, const CBS *in_sigalgs) { 3206 /* Extension ignored for inappropriate versions */ 3207 if (ssl3_protocol_version(hs->ssl) < TLS1_2_VERSION) { 3208 return 1; 3209 } 3210 3211 OPENSSL_free(hs->peer_sigalgs); 3212 hs->peer_sigalgs = NULL; 3213 hs->num_peer_sigalgs = 0; 3214 3215 size_t num_sigalgs = CBS_len(in_sigalgs); 3216 if (num_sigalgs % 2 != 0) { 3217 return 0; 3218 } 3219 num_sigalgs /= 2; 3220 3221 /* supported_signature_algorithms in the certificate request is 3222 * allowed to be empty. */ 3223 if (num_sigalgs == 0) { 3224 return 1; 3225 } 3226 3227 /* This multiplication doesn't overflow because sizeof(uint16_t) is two 3228 * and we just divided |num_sigalgs| by two. */ 3229 hs->peer_sigalgs = (uint16_t *)OPENSSL_malloc(num_sigalgs * sizeof(uint16_t)); 3230 if (hs->peer_sigalgs == NULL) { 3231 return 0; 3232 } 3233 hs->num_peer_sigalgs = num_sigalgs; 3234 3235 CBS sigalgs; 3236 CBS_init(&sigalgs, CBS_data(in_sigalgs), CBS_len(in_sigalgs)); 3237 for (size_t i = 0; i < num_sigalgs; i++) { 3238 if (!CBS_get_u16(&sigalgs, &hs->peer_sigalgs[i])) { 3239 return 0; 3240 } 3241 } 3242 3243 return 1; 3244 } 3245 3246 int tls1_get_legacy_signature_algorithm(uint16_t *out, const EVP_PKEY *pkey) { 3247 switch (EVP_PKEY_id(pkey)) { 3248 case EVP_PKEY_RSA: 3249 *out = SSL_SIGN_RSA_PKCS1_MD5_SHA1; 3250 return 1; 3251 case EVP_PKEY_EC: 3252 *out = SSL_SIGN_ECDSA_SHA1; 3253 return 1; 3254 default: 3255 return 0; 3256 } 3257 } 3258 3259 int tls1_choose_signature_algorithm(SSL_HANDSHAKE *hs, uint16_t *out) { 3260 SSL *const ssl = hs->ssl; 3261 CERT *cert = ssl->cert; 3262 3263 /* Before TLS 1.2, the signature algorithm isn't negotiated as part of the 3264 * handshake. */ 3265 if (ssl3_protocol_version(ssl) < TLS1_2_VERSION) { 3266 if (!tls1_get_legacy_signature_algorithm(out, hs->local_pubkey)) { 3267 OPENSSL_PUT_ERROR(SSL, SSL_R_NO_COMMON_SIGNATURE_ALGORITHMS); 3268 return 0; 3269 } 3270 return 1; 3271 } 3272 3273 const uint16_t *sigalgs = cert->sigalgs; 3274 size_t num_sigalgs = cert->num_sigalgs; 3275 if (sigalgs == NULL) { 3276 sigalgs = kSignSignatureAlgorithms; 3277 num_sigalgs = OPENSSL_ARRAY_SIZE(kSignSignatureAlgorithms); 3278 } 3279 3280 const uint16_t *peer_sigalgs = hs->peer_sigalgs; 3281 size_t num_peer_sigalgs = hs->num_peer_sigalgs; 3282 if (num_peer_sigalgs == 0 && ssl3_protocol_version(ssl) < TLS1_3_VERSION) { 3283 /* If the client didn't specify any signature_algorithms extension then 3284 * we can assume that it supports SHA1. See 3285 * http://tools.ietf.org/html/rfc5246#section-7.4.1.4.1 */ 3286 static const uint16_t kDefaultPeerAlgorithms[] = {SSL_SIGN_RSA_PKCS1_SHA1, 3287 SSL_SIGN_ECDSA_SHA1}; 3288 peer_sigalgs = kDefaultPeerAlgorithms; 3289 num_peer_sigalgs = OPENSSL_ARRAY_SIZE(kDefaultPeerAlgorithms); 3290 } 3291 3292 for (size_t i = 0; i < num_sigalgs; i++) { 3293 uint16_t sigalg = sigalgs[i]; 3294 /* SSL_SIGN_RSA_PKCS1_MD5_SHA1 is an internal value and should never be 3295 * negotiated. */ 3296 if (sigalg == SSL_SIGN_RSA_PKCS1_MD5_SHA1 || 3297 !ssl_private_key_supports_signature_algorithm(hs, sigalgs[i])) { 3298 continue; 3299 } 3300 3301 for (size_t j = 0; j < num_peer_sigalgs; j++) { 3302 if (sigalg == peer_sigalgs[j]) { 3303 *out = sigalg; 3304 return 1; 3305 } 3306 } 3307 } 3308 3309 OPENSSL_PUT_ERROR(SSL, SSL_R_NO_COMMON_SIGNATURE_ALGORITHMS); 3310 return 0; 3311 } 3312 3313 int tls1_verify_channel_id(SSL_HANDSHAKE *hs) { 3314 SSL *const ssl = hs->ssl; 3315 uint16_t extension_type; 3316 CBS extension, channel_id; 3317 3318 /* A Channel ID handshake message is structured to contain multiple 3319 * extensions, but the only one that can be present is Channel ID. */ 3320 CBS_init(&channel_id, ssl->init_msg, ssl->init_num); 3321 if (!CBS_get_u16(&channel_id, &extension_type) || 3322 !CBS_get_u16_length_prefixed(&channel_id, &extension) || 3323 CBS_len(&channel_id) != 0 || 3324 extension_type != TLSEXT_TYPE_channel_id || 3325 CBS_len(&extension) != TLSEXT_CHANNEL_ID_SIZE) { 3326 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 3327 ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); 3328 return 0; 3329 } 3330 3331 bssl::UniquePtr<EC_GROUP> p256( 3332 EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1)); 3333 if (!p256) { 3334 OPENSSL_PUT_ERROR(SSL, SSL_R_NO_P256_SUPPORT); 3335 return 0; 3336 } 3337 3338 bssl::UniquePtr<ECDSA_SIG> sig(ECDSA_SIG_new()); 3339 bssl::UniquePtr<BIGNUM> x(BN_new()), y(BN_new()); 3340 if (!sig || !x || !y) { 3341 return 0; 3342 } 3343 3344 const uint8_t *p = CBS_data(&extension); 3345 if (BN_bin2bn(p + 0, 32, x.get()) == NULL || 3346 BN_bin2bn(p + 32, 32, y.get()) == NULL || 3347 BN_bin2bn(p + 64, 32, sig->r) == NULL || 3348 BN_bin2bn(p + 96, 32, sig->s) == NULL) { 3349 return 0; 3350 } 3351 3352 bssl::UniquePtr<EC_KEY> key(EC_KEY_new()); 3353 bssl::UniquePtr<EC_POINT> point(EC_POINT_new(p256.get())); 3354 if (!key || !point || 3355 !EC_POINT_set_affine_coordinates_GFp(p256.get(), point.get(), x.get(), 3356 y.get(), nullptr) || 3357 !EC_KEY_set_group(key.get(), p256.get()) || 3358 !EC_KEY_set_public_key(key.get(), point.get())) { 3359 return 0; 3360 } 3361 3362 uint8_t digest[EVP_MAX_MD_SIZE]; 3363 size_t digest_len; 3364 if (!tls1_channel_id_hash(hs, digest, &digest_len)) { 3365 return 0; 3366 } 3367 3368 int sig_ok = ECDSA_do_verify(digest, digest_len, sig.get(), key.get()); 3369 #if defined(BORINGSSL_UNSAFE_FUZZER_MODE) 3370 sig_ok = 1; 3371 #endif 3372 if (!sig_ok) { 3373 OPENSSL_PUT_ERROR(SSL, SSL_R_CHANNEL_ID_SIGNATURE_INVALID); 3374 ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR); 3375 ssl->s3->tlsext_channel_id_valid = 0; 3376 return 0; 3377 } 3378 3379 OPENSSL_memcpy(ssl->s3->tlsext_channel_id, p, 64); 3380 return 1; 3381 } 3382 3383 int tls1_write_channel_id(SSL_HANDSHAKE *hs, CBB *cbb) { 3384 SSL *const ssl = hs->ssl; 3385 uint8_t digest[EVP_MAX_MD_SIZE]; 3386 size_t digest_len; 3387 if (!tls1_channel_id_hash(hs, digest, &digest_len)) { 3388 return 0; 3389 } 3390 3391 EC_KEY *ec_key = EVP_PKEY_get0_EC_KEY(ssl->tlsext_channel_id_private); 3392 if (ec_key == NULL) { 3393 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 3394 return 0; 3395 } 3396 3397 int ret = 0; 3398 BIGNUM *x = BN_new(); 3399 BIGNUM *y = BN_new(); 3400 ECDSA_SIG *sig = NULL; 3401 if (x == NULL || y == NULL || 3402 !EC_POINT_get_affine_coordinates_GFp(EC_KEY_get0_group(ec_key), 3403 EC_KEY_get0_public_key(ec_key), 3404 x, y, NULL)) { 3405 goto err; 3406 } 3407 3408 sig = ECDSA_do_sign(digest, digest_len, ec_key); 3409 if (sig == NULL) { 3410 goto err; 3411 } 3412 3413 CBB child; 3414 if (!CBB_add_u16(cbb, TLSEXT_TYPE_channel_id) || 3415 !CBB_add_u16_length_prefixed(cbb, &child) || 3416 !BN_bn2cbb_padded(&child, 32, x) || 3417 !BN_bn2cbb_padded(&child, 32, y) || 3418 !BN_bn2cbb_padded(&child, 32, sig->r) || 3419 !BN_bn2cbb_padded(&child, 32, sig->s) || 3420 !CBB_flush(cbb)) { 3421 goto err; 3422 } 3423 3424 ret = 1; 3425 3426 err: 3427 BN_free(x); 3428 BN_free(y); 3429 ECDSA_SIG_free(sig); 3430 return ret; 3431 } 3432 3433 int tls1_channel_id_hash(SSL_HANDSHAKE *hs, uint8_t *out, size_t *out_len) { 3434 SSL *const ssl = hs->ssl; 3435 if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 3436 uint8_t *msg; 3437 size_t msg_len; 3438 if (!tls13_get_cert_verify_signature_input(hs, &msg, &msg_len, 3439 ssl_cert_verify_channel_id)) { 3440 return 0; 3441 } 3442 SHA256(msg, msg_len, out); 3443 *out_len = SHA256_DIGEST_LENGTH; 3444 OPENSSL_free(msg); 3445 return 1; 3446 } 3447 3448 SHA256_CTX ctx; 3449 3450 SHA256_Init(&ctx); 3451 static const char kClientIDMagic[] = "TLS Channel ID signature"; 3452 SHA256_Update(&ctx, kClientIDMagic, sizeof(kClientIDMagic)); 3453 3454 if (ssl->session != NULL) { 3455 static const char kResumptionMagic[] = "Resumption"; 3456 SHA256_Update(&ctx, kResumptionMagic, sizeof(kResumptionMagic)); 3457 if (ssl->session->original_handshake_hash_len == 0) { 3458 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 3459 return 0; 3460 } 3461 SHA256_Update(&ctx, ssl->session->original_handshake_hash, 3462 ssl->session->original_handshake_hash_len); 3463 } 3464 3465 uint8_t hs_hash[EVP_MAX_MD_SIZE]; 3466 size_t hs_hash_len; 3467 if (!SSL_TRANSCRIPT_get_hash(&hs->transcript, hs_hash, &hs_hash_len)) { 3468 return 0; 3469 } 3470 SHA256_Update(&ctx, hs_hash, (size_t)hs_hash_len); 3471 SHA256_Final(out, &ctx); 3472 *out_len = SHA256_DIGEST_LENGTH; 3473 return 1; 3474 } 3475 3476 /* tls1_record_handshake_hashes_for_channel_id records the current handshake 3477 * hashes in |hs->new_session| so that Channel ID resumptions can sign that 3478 * data. */ 3479 int tls1_record_handshake_hashes_for_channel_id(SSL_HANDSHAKE *hs) { 3480 SSL *const ssl = hs->ssl; 3481 /* This function should never be called for a resumed session because the 3482 * handshake hashes that we wish to record are for the original, full 3483 * handshake. */ 3484 if (ssl->session != NULL) { 3485 return -1; 3486 } 3487 3488 static_assert( 3489 sizeof(hs->new_session->original_handshake_hash) == EVP_MAX_MD_SIZE, 3490 "original_handshake_hash is too small"); 3491 3492 size_t digest_len; 3493 if (!SSL_TRANSCRIPT_get_hash(&hs->transcript, 3494 hs->new_session->original_handshake_hash, 3495 &digest_len)) { 3496 return -1; 3497 } 3498 3499 static_assert(EVP_MAX_MD_SIZE <= 0xff, 3500 "EVP_MAX_MD_SIZE does not fit in uint8_t"); 3501 hs->new_session->original_handshake_hash_len = (uint8_t)digest_len; 3502 3503 return 1; 3504 } 3505 3506 int ssl_do_channel_id_callback(SSL *ssl) { 3507 if (ssl->tlsext_channel_id_private != NULL || 3508 ssl->ctx->channel_id_cb == NULL) { 3509 return 1; 3510 } 3511 3512 EVP_PKEY *key = NULL; 3513 ssl->ctx->channel_id_cb(ssl, &key); 3514 if (key == NULL) { 3515 /* The caller should try again later. */ 3516 return 1; 3517 } 3518 3519 int ret = SSL_set1_tls_channel_id(ssl, key); 3520 EVP_PKEY_free(key); 3521 return ret; 3522 } 3523 3524 int ssl_is_sct_list_valid(const CBS *contents) { 3525 /* Shallow parse the SCT list for sanity. By the RFC 3526 * (https://tools.ietf.org/html/rfc6962#section-3.3) neither the list nor any 3527 * of the SCTs may be empty. */ 3528 CBS copy = *contents; 3529 CBS sct_list; 3530 if (!CBS_get_u16_length_prefixed(©, &sct_list) || 3531 CBS_len(©) != 0 || 3532 CBS_len(&sct_list) == 0) { 3533 return 0; 3534 } 3535 3536 while (CBS_len(&sct_list) > 0) { 3537 CBS sct; 3538 if (!CBS_get_u16_length_prefixed(&sct_list, &sct) || 3539 CBS_len(&sct) == 0) { 3540 return 0; 3541 } 3542 } 3543 3544 return 1; 3545 } 3546
