1/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) 2 * All rights reserved. 3 * 4 * This package is an SSL implementation written 5 * by Eric Young (eay@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@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@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@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@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@cryptsoft.com). This product includes software written by Tim 107 * Hudson (tjh@cryptsoft.com). 108 * 109 */ 110/* ==================================================================== 111 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED. 112 * 113 * Portions of the attached software ("Contribution") are developed by 114 * SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project. 115 * 116 * The Contribution is licensed pursuant to the OpenSSL open source 117 * license provided above. 118 * 119 * ECC cipher suite support in OpenSSL originally written by 120 * Vipul Gupta and Sumit Gupta of Sun Microsystems Laboratories. 121 * 122 */ 123/* ==================================================================== 124 * Copyright 2005 Nokia. All rights reserved. 125 * 126 * The portions of the attached software ("Contribution") is developed by 127 * Nokia Corporation and is licensed pursuant to the OpenSSL open source 128 * license. 129 * 130 * The Contribution, originally written by Mika Kousa and Pasi Eronen of 131 * Nokia Corporation, consists of the "PSK" (Pre-Shared Key) ciphersuites 132 * support (see RFC 4279) to OpenSSL. 133 * 134 * No patent licenses or other rights except those expressly stated in 135 * the OpenSSL open source license shall be deemed granted or received 136 * expressly, by implication, estoppel, or otherwise. 137 * 138 * No assurances are provided by Nokia that the Contribution does not 139 * infringe the patent or other intellectual property rights of any third 140 * party or that the license provides you with all the necessary rights 141 * to make use of the Contribution. 142 * 143 * THE SOFTWARE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. IN 144 * ADDITION TO THE DISCLAIMERS INCLUDED IN THE LICENSE, NOKIA 145 * SPECIFICALLY DISCLAIMS ANY LIABILITY FOR CLAIMS BROUGHT BY YOU OR ANY 146 * OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OR 147 * OTHERWISE. */ 148 149#include <openssl/ssl.h> 150 151#include <assert.h> 152#include <string.h> 153 154#include <openssl/bn.h> 155#include <openssl/buf.h> 156#include <openssl/bytestring.h> 157#include <openssl/cipher.h> 158#include <openssl/ec.h> 159#include <openssl/ecdsa.h> 160#include <openssl/err.h> 161#include <openssl/evp.h> 162#include <openssl/hmac.h> 163#include <openssl/md5.h> 164#include <openssl/mem.h> 165#include <openssl/nid.h> 166#include <openssl/rand.h> 167#include <openssl/x509.h> 168 169#include "internal.h" 170#include "../crypto/internal.h" 171 172 173namespace bssl { 174 175enum ssl_server_hs_state_t { 176 state_start_accept = 0, 177 state_read_client_hello, 178 state_select_certificate, 179 state_tls13, 180 state_select_parameters, 181 state_send_server_hello, 182 state_send_server_certificate, 183 state_send_server_key_exchange, 184 state_send_server_hello_done, 185 state_read_client_certificate, 186 state_verify_client_certificate, 187 state_read_client_key_exchange, 188 state_read_client_certificate_verify, 189 state_read_change_cipher_spec, 190 state_process_change_cipher_spec, 191 state_read_next_proto, 192 state_read_channel_id, 193 state_read_client_finished, 194 state_send_server_finished, 195 state_finish_server_handshake, 196 state_done, 197}; 198 199int ssl_client_cipher_list_contains_cipher(const SSL_CLIENT_HELLO *client_hello, 200 uint16_t id) { 201 CBS cipher_suites; 202 CBS_init(&cipher_suites, client_hello->cipher_suites, 203 client_hello->cipher_suites_len); 204 205 while (CBS_len(&cipher_suites) > 0) { 206 uint16_t got_id; 207 if (!CBS_get_u16(&cipher_suites, &got_id)) { 208 return 0; 209 } 210 211 if (got_id == id) { 212 return 1; 213 } 214 } 215 216 return 0; 217} 218 219static int negotiate_version(SSL_HANDSHAKE *hs, uint8_t *out_alert, 220 const SSL_CLIENT_HELLO *client_hello) { 221 SSL *const ssl = hs->ssl; 222 assert(!ssl->s3->have_version); 223 CBS supported_versions, versions; 224 if (ssl_client_hello_get_extension(client_hello, &supported_versions, 225 TLSEXT_TYPE_supported_versions)) { 226 if (!CBS_get_u8_length_prefixed(&supported_versions, &versions) || 227 CBS_len(&supported_versions) != 0 || 228 CBS_len(&versions) == 0) { 229 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 230 *out_alert = SSL_AD_DECODE_ERROR; 231 return 0; 232 } 233 } else { 234 // Convert the ClientHello version to an equivalent supported_versions 235 // extension. 236 static const uint8_t kTLSVersions[] = { 237 0x03, 0x03, // TLS 1.2 238 0x03, 0x02, // TLS 1.1 239 0x03, 0x01, // TLS 1 240 0x03, 0x00, // SSL 3 241 }; 242 243 static const uint8_t kDTLSVersions[] = { 244 0xfe, 0xfd, // DTLS 1.2 245 0xfe, 0xff, // DTLS 1.0 246 }; 247 248 size_t versions_len = 0; 249 if (SSL_is_dtls(ssl)) { 250 if (client_hello->version <= DTLS1_2_VERSION) { 251 versions_len = 4; 252 } else if (client_hello->version <= DTLS1_VERSION) { 253 versions_len = 2; 254 } 255 CBS_init(&versions, kDTLSVersions + sizeof(kDTLSVersions) - versions_len, 256 versions_len); 257 } else { 258 if (client_hello->version >= TLS1_2_VERSION) { 259 versions_len = 8; 260 } else if (client_hello->version >= TLS1_1_VERSION) { 261 versions_len = 6; 262 } else if (client_hello->version >= TLS1_VERSION) { 263 versions_len = 4; 264 } else if (client_hello->version >= SSL3_VERSION) { 265 versions_len = 2; 266 } 267 CBS_init(&versions, kTLSVersions + sizeof(kTLSVersions) - versions_len, 268 versions_len); 269 } 270 } 271 272 if (!ssl_negotiate_version(hs, out_alert, &ssl->version, &versions)) { 273 return 0; 274 } 275 276 // At this point, the connection's version is known and |ssl->version| is 277 // fixed. Begin enforcing the record-layer version. 278 ssl->s3->have_version = true; 279 ssl->s3->aead_write_ctx->SetVersionIfNullCipher(ssl->version); 280 281 // Handle FALLBACK_SCSV. 282 if (ssl_client_cipher_list_contains_cipher(client_hello, 283 SSL3_CK_FALLBACK_SCSV & 0xffff) && 284 ssl_protocol_version(ssl) < hs->max_version) { 285 OPENSSL_PUT_ERROR(SSL, SSL_R_INAPPROPRIATE_FALLBACK); 286 *out_alert = SSL3_AD_INAPPROPRIATE_FALLBACK; 287 return 0; 288 } 289 290 return 1; 291} 292 293static UniquePtr<STACK_OF(SSL_CIPHER)> ssl_parse_client_cipher_list( 294 const SSL_CLIENT_HELLO *client_hello) { 295 CBS cipher_suites; 296 CBS_init(&cipher_suites, client_hello->cipher_suites, 297 client_hello->cipher_suites_len); 298 299 UniquePtr<STACK_OF(SSL_CIPHER)> sk(sk_SSL_CIPHER_new_null()); 300 if (!sk) { 301 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); 302 return nullptr; 303 } 304 305 while (CBS_len(&cipher_suites) > 0) { 306 uint16_t cipher_suite; 307 308 if (!CBS_get_u16(&cipher_suites, &cipher_suite)) { 309 OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_IN_RECEIVED_CIPHER_LIST); 310 return nullptr; 311 } 312 313 const SSL_CIPHER *c = SSL_get_cipher_by_value(cipher_suite); 314 if (c != NULL && !sk_SSL_CIPHER_push(sk.get(), c)) { 315 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); 316 return nullptr; 317 } 318 } 319 320 return sk; 321} 322 323// ssl_get_compatible_server_ciphers determines the key exchange and 324// authentication cipher suite masks compatible with the server configuration 325// and current ClientHello parameters of |hs|. It sets |*out_mask_k| to the key 326// exchange mask and |*out_mask_a| to the authentication mask. 327static void ssl_get_compatible_server_ciphers(SSL_HANDSHAKE *hs, 328 uint32_t *out_mask_k, 329 uint32_t *out_mask_a) { 330 SSL *const ssl = hs->ssl; 331 uint32_t mask_k = 0; 332 uint32_t mask_a = 0; 333 334 if (ssl_has_certificate(ssl)) { 335 mask_a |= ssl_cipher_auth_mask_for_key(hs->local_pubkey.get()); 336 if (EVP_PKEY_id(hs->local_pubkey.get()) == EVP_PKEY_RSA) { 337 mask_k |= SSL_kRSA; 338 } 339 } 340 341 // Check for a shared group to consider ECDHE ciphers. 342 uint16_t unused; 343 if (tls1_get_shared_group(hs, &unused)) { 344 mask_k |= SSL_kECDHE; 345 } 346 347 // PSK requires a server callback. 348 if (ssl->psk_server_callback != NULL) { 349 mask_k |= SSL_kPSK; 350 mask_a |= SSL_aPSK; 351 } 352 353 *out_mask_k = mask_k; 354 *out_mask_a = mask_a; 355} 356 357static const SSL_CIPHER *ssl3_choose_cipher( 358 SSL_HANDSHAKE *hs, const SSL_CLIENT_HELLO *client_hello, 359 const struct ssl_cipher_preference_list_st *server_pref) { 360 SSL *const ssl = hs->ssl; 361 STACK_OF(SSL_CIPHER) *prio, *allow; 362 // in_group_flags will either be NULL, or will point to an array of bytes 363 // which indicate equal-preference groups in the |prio| stack. See the 364 // comment about |in_group_flags| in the |ssl_cipher_preference_list_st| 365 // struct. 366 const uint8_t *in_group_flags; 367 // group_min contains the minimal index so far found in a group, or -1 if no 368 // such value exists yet. 369 int group_min = -1; 370 371 UniquePtr<STACK_OF(SSL_CIPHER)> client_pref = 372 ssl_parse_client_cipher_list(client_hello); 373 if (!client_pref) { 374 return nullptr; 375 } 376 377 if (ssl->options & SSL_OP_CIPHER_SERVER_PREFERENCE) { 378 prio = server_pref->ciphers; 379 in_group_flags = server_pref->in_group_flags; 380 allow = client_pref.get(); 381 } else { 382 prio = client_pref.get(); 383 in_group_flags = NULL; 384 allow = server_pref->ciphers; 385 } 386 387 uint32_t mask_k, mask_a; 388 ssl_get_compatible_server_ciphers(hs, &mask_k, &mask_a); 389 390 for (size_t i = 0; i < sk_SSL_CIPHER_num(prio); i++) { 391 const SSL_CIPHER *c = sk_SSL_CIPHER_value(prio, i); 392 393 size_t cipher_index; 394 if (// Check if the cipher is supported for the current version. 395 SSL_CIPHER_get_min_version(c) <= ssl_protocol_version(ssl) && 396 ssl_protocol_version(ssl) <= SSL_CIPHER_get_max_version(c) && 397 // Check the cipher is supported for the server configuration. 398 (c->algorithm_mkey & mask_k) && 399 (c->algorithm_auth & mask_a) && 400 // Check the cipher is in the |allow| list. 401 sk_SSL_CIPHER_find(allow, &cipher_index, c)) { 402 if (in_group_flags != NULL && in_group_flags[i] == 1) { 403 // This element of |prio| is in a group. Update the minimum index found 404 // so far and continue looking. 405 if (group_min == -1 || (size_t)group_min > cipher_index) { 406 group_min = cipher_index; 407 } 408 } else { 409 if (group_min != -1 && (size_t)group_min < cipher_index) { 410 cipher_index = group_min; 411 } 412 return sk_SSL_CIPHER_value(allow, cipher_index); 413 } 414 } 415 416 if (in_group_flags != NULL && in_group_flags[i] == 0 && group_min != -1) { 417 // We are about to leave a group, but we found a match in it, so that's 418 // our answer. 419 return sk_SSL_CIPHER_value(allow, group_min); 420 } 421 } 422 423 return nullptr; 424} 425 426static enum ssl_hs_wait_t do_start_accept(SSL_HANDSHAKE *hs) { 427 ssl_do_info_callback(hs->ssl, SSL_CB_HANDSHAKE_START, 1); 428 hs->state = state_read_client_hello; 429 return ssl_hs_ok; 430} 431 432static enum ssl_hs_wait_t do_read_client_hello(SSL_HANDSHAKE *hs) { 433 SSL *const ssl = hs->ssl; 434 435 SSLMessage msg; 436 if (!ssl->method->get_message(ssl, &msg)) { 437 return ssl_hs_read_message; 438 } 439 440 if (!ssl_check_message_type(ssl, msg, SSL3_MT_CLIENT_HELLO)) { 441 return ssl_hs_error; 442 } 443 444 if (ssl->handoff) { 445 return ssl_hs_handoff; 446 } 447 448 SSL_CLIENT_HELLO client_hello; 449 if (!ssl_client_hello_init(ssl, &client_hello, msg)) { 450 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 451 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); 452 return ssl_hs_error; 453 } 454 455 // Run the early callback. 456 if (ssl->ctx->select_certificate_cb != NULL) { 457 switch (ssl->ctx->select_certificate_cb(&client_hello)) { 458 case ssl_select_cert_retry: 459 return ssl_hs_certificate_selection_pending; 460 461 case ssl_select_cert_error: 462 // Connection rejected. 463 OPENSSL_PUT_ERROR(SSL, SSL_R_CONNECTION_REJECTED); 464 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE); 465 return ssl_hs_error; 466 467 default: 468 /* fallthrough */; 469 } 470 } 471 472 // Freeze the version range after the early callback. 473 if (!ssl_get_version_range(ssl, &hs->min_version, &hs->max_version)) { 474 return ssl_hs_error; 475 } 476 477 uint8_t alert = SSL_AD_DECODE_ERROR; 478 if (!negotiate_version(hs, &alert, &client_hello)) { 479 ssl_send_alert(ssl, SSL3_AL_FATAL, alert); 480 return ssl_hs_error; 481 } 482 483 hs->client_version = client_hello.version; 484 if (client_hello.random_len != SSL3_RANDOM_SIZE) { 485 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 486 return ssl_hs_error; 487 } 488 OPENSSL_memcpy(ssl->s3->client_random, client_hello.random, 489 client_hello.random_len); 490 491 // Only null compression is supported. TLS 1.3 further requires the peer 492 // advertise no other compression. 493 if (OPENSSL_memchr(client_hello.compression_methods, 0, 494 client_hello.compression_methods_len) == NULL || 495 (ssl_protocol_version(ssl) >= TLS1_3_VERSION && 496 client_hello.compression_methods_len != 1)) { 497 OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_COMPRESSION_LIST); 498 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); 499 return ssl_hs_error; 500 } 501 502 // TLS extensions. 503 if (!ssl_parse_clienthello_tlsext(hs, &client_hello)) { 504 OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT); 505 return ssl_hs_error; 506 } 507 508 hs->state = state_select_certificate; 509 return ssl_hs_ok; 510} 511 512static enum ssl_hs_wait_t do_select_certificate(SSL_HANDSHAKE *hs) { 513 SSL *const ssl = hs->ssl; 514 515 SSLMessage msg; 516 if (!ssl->method->get_message(ssl, &msg)) { 517 return ssl_hs_read_message; 518 } 519 520 // Call |cert_cb| to update server certificates if required. 521 if (ssl->cert->cert_cb != NULL) { 522 int rv = ssl->cert->cert_cb(ssl, ssl->cert->cert_cb_arg); 523 if (rv == 0) { 524 OPENSSL_PUT_ERROR(SSL, SSL_R_CERT_CB_ERROR); 525 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); 526 return ssl_hs_error; 527 } 528 if (rv < 0) { 529 return ssl_hs_x509_lookup; 530 } 531 } 532 533 if (!ssl_on_certificate_selected(hs)) { 534 return ssl_hs_error; 535 } 536 537 if (ssl_protocol_version(ssl) >= TLS1_3_VERSION) { 538 // Jump to the TLS 1.3 state machine. 539 hs->state = state_tls13; 540 return ssl_hs_ok; 541 } 542 543 SSL_CLIENT_HELLO client_hello; 544 if (!ssl_client_hello_init(ssl, &client_hello, msg)) { 545 return ssl_hs_error; 546 } 547 548 // Negotiate the cipher suite. This must be done after |cert_cb| so the 549 // certificate is finalized. 550 hs->new_cipher = 551 ssl3_choose_cipher(hs, &client_hello, ssl_get_cipher_preferences(ssl)); 552 if (hs->new_cipher == NULL) { 553 OPENSSL_PUT_ERROR(SSL, SSL_R_NO_SHARED_CIPHER); 554 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE); 555 return ssl_hs_error; 556 } 557 558 hs->state = state_select_parameters; 559 return ssl_hs_ok; 560} 561 562static enum ssl_hs_wait_t do_tls13(SSL_HANDSHAKE *hs) { 563 enum ssl_hs_wait_t wait = tls13_server_handshake(hs); 564 if (wait == ssl_hs_ok) { 565 hs->state = state_finish_server_handshake; 566 return ssl_hs_ok; 567 } 568 569 return wait; 570} 571 572static enum ssl_hs_wait_t do_select_parameters(SSL_HANDSHAKE *hs) { 573 SSL *const ssl = hs->ssl; 574 575 SSLMessage msg; 576 if (!ssl->method->get_message(ssl, &msg)) { 577 return ssl_hs_read_message; 578 } 579 580 SSL_CLIENT_HELLO client_hello; 581 if (!ssl_client_hello_init(ssl, &client_hello, msg)) { 582 return ssl_hs_error; 583 } 584 585 // Determine whether we are doing session resumption. 586 UniquePtr<SSL_SESSION> session; 587 bool tickets_supported = false, renew_ticket = false; 588 enum ssl_hs_wait_t wait = ssl_get_prev_session( 589 ssl, &session, &tickets_supported, &renew_ticket, &client_hello); 590 if (wait != ssl_hs_ok) { 591 return wait; 592 } 593 594 if (session) { 595 if (session->extended_master_secret && !hs->extended_master_secret) { 596 // A ClientHello without EMS that attempts to resume a session with EMS 597 // is fatal to the connection. 598 OPENSSL_PUT_ERROR(SSL, SSL_R_RESUMED_EMS_SESSION_WITHOUT_EMS_EXTENSION); 599 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE); 600 return ssl_hs_error; 601 } 602 603 if (!ssl_session_is_resumable(hs, session.get()) || 604 // If the client offers the EMS extension, but the previous session 605 // didn't use it, then negotiate a new session. 606 hs->extended_master_secret != session->extended_master_secret) { 607 session.reset(); 608 } 609 } 610 611 if (session) { 612 // Use the old session. 613 hs->ticket_expected = renew_ticket; 614 ssl->session = session.release(); 615 ssl->s3->session_reused = true; 616 } else { 617 hs->ticket_expected = tickets_supported; 618 ssl_set_session(ssl, NULL); 619 if (!ssl_get_new_session(hs, 1 /* server */)) { 620 return ssl_hs_error; 621 } 622 623 // Clear the session ID if we want the session to be single-use. 624 if (!(ssl->ctx->session_cache_mode & SSL_SESS_CACHE_SERVER)) { 625 hs->new_session->session_id_length = 0; 626 } 627 } 628 629 if (ssl->ctx->dos_protection_cb != NULL && 630 ssl->ctx->dos_protection_cb(&client_hello) == 0) { 631 // Connection rejected for DOS reasons. 632 OPENSSL_PUT_ERROR(SSL, SSL_R_CONNECTION_REJECTED); 633 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); 634 return ssl_hs_error; 635 } 636 637 if (ssl->session == NULL) { 638 hs->new_session->cipher = hs->new_cipher; 639 640 // Determine whether to request a client certificate. 641 hs->cert_request = !!(ssl->verify_mode & SSL_VERIFY_PEER); 642 // Only request a certificate if Channel ID isn't negotiated. 643 if ((ssl->verify_mode & SSL_VERIFY_PEER_IF_NO_OBC) && 644 ssl->s3->tlsext_channel_id_valid) { 645 hs->cert_request = false; 646 } 647 // CertificateRequest may only be sent in certificate-based ciphers. 648 if (!ssl_cipher_uses_certificate_auth(hs->new_cipher)) { 649 hs->cert_request = false; 650 } 651 652 if (!hs->cert_request) { 653 // OpenSSL returns X509_V_OK when no certificates are requested. This is 654 // classed by them as a bug, but it's assumed by at least NGINX. 655 hs->new_session->verify_result = X509_V_OK; 656 } 657 } 658 659 // HTTP/2 negotiation depends on the cipher suite, so ALPN negotiation was 660 // deferred. Complete it now. 661 uint8_t alert = SSL_AD_DECODE_ERROR; 662 if (!ssl_negotiate_alpn(hs, &alert, &client_hello)) { 663 ssl_send_alert(ssl, SSL3_AL_FATAL, alert); 664 return ssl_hs_error; 665 } 666 667 // Now that all parameters are known, initialize the handshake hash and hash 668 // the ClientHello. 669 if (!hs->transcript.InitHash(ssl_protocol_version(ssl), hs->new_cipher) || 670 !ssl_hash_message(hs, msg)) { 671 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); 672 return ssl_hs_error; 673 } 674 675 // Release the handshake buffer if client authentication isn't required. 676 if (!hs->cert_request) { 677 hs->transcript.FreeBuffer(); 678 } 679 680 ssl->method->next_message(ssl); 681 682 hs->state = state_send_server_hello; 683 return ssl_hs_ok; 684} 685 686static enum ssl_hs_wait_t do_send_server_hello(SSL_HANDSHAKE *hs) { 687 SSL *const ssl = hs->ssl; 688 689 // We only accept ChannelIDs on connections with ECDHE in order to avoid a 690 // known attack while we fix ChannelID itself. 691 if (ssl->s3->tlsext_channel_id_valid && 692 (hs->new_cipher->algorithm_mkey & SSL_kECDHE) == 0) { 693 ssl->s3->tlsext_channel_id_valid = false; 694 } 695 696 // If this is a resumption and the original handshake didn't support 697 // ChannelID then we didn't record the original handshake hashes in the 698 // session and so cannot resume with ChannelIDs. 699 if (ssl->session != NULL && 700 ssl->session->original_handshake_hash_len == 0) { 701 ssl->s3->tlsext_channel_id_valid = false; 702 } 703 704 struct OPENSSL_timeval now; 705 ssl_get_current_time(ssl, &now); 706 ssl->s3->server_random[0] = now.tv_sec >> 24; 707 ssl->s3->server_random[1] = now.tv_sec >> 16; 708 ssl->s3->server_random[2] = now.tv_sec >> 8; 709 ssl->s3->server_random[3] = now.tv_sec; 710 if (!RAND_bytes(ssl->s3->server_random + 4, SSL3_RANDOM_SIZE - 4)) { 711 return ssl_hs_error; 712 } 713 714 // Implement the TLS 1.3 anti-downgrade feature, but with a different value. 715 // 716 // For draft TLS 1.3 versions, it is not safe to deploy this feature. However, 717 // some TLS terminators are non-compliant and copy the origin server's value, 718 // so we wish to measure eventual compatibility impact. 719 if (hs->max_version >= TLS1_3_VERSION) { 720 OPENSSL_memcpy(ssl->s3->server_random + SSL3_RANDOM_SIZE - 721 sizeof(kDraftDowngradeRandom), 722 kDraftDowngradeRandom, sizeof(kDraftDowngradeRandom)); 723 } 724 725 const SSL_SESSION *session = hs->new_session.get(); 726 if (ssl->session != NULL) { 727 session = ssl->session; 728 } 729 730 ScopedCBB cbb; 731 CBB body, session_id; 732 if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_SERVER_HELLO) || 733 !CBB_add_u16(&body, ssl->version) || 734 !CBB_add_bytes(&body, ssl->s3->server_random, SSL3_RANDOM_SIZE) || 735 !CBB_add_u8_length_prefixed(&body, &session_id) || 736 !CBB_add_bytes(&session_id, session->session_id, 737 session->session_id_length) || 738 !CBB_add_u16(&body, ssl_cipher_get_value(hs->new_cipher)) || 739 !CBB_add_u8(&body, 0 /* no compression */) || 740 !ssl_add_serverhello_tlsext(hs, &body) || 741 !ssl_add_message_cbb(ssl, cbb.get())) { 742 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 743 return ssl_hs_error; 744 } 745 746 if (ssl->session != NULL) { 747 hs->state = state_send_server_finished; 748 } else { 749 hs->state = state_send_server_certificate; 750 } 751 return ssl_hs_ok; 752} 753 754static enum ssl_hs_wait_t do_send_server_certificate(SSL_HANDSHAKE *hs) { 755 SSL *const ssl = hs->ssl; 756 ScopedCBB cbb; 757 758 if (ssl_cipher_uses_certificate_auth(hs->new_cipher)) { 759 if (!ssl_has_certificate(ssl)) { 760 OPENSSL_PUT_ERROR(SSL, SSL_R_NO_CERTIFICATE_SET); 761 return ssl_hs_error; 762 } 763 764 if (!ssl_output_cert_chain(ssl)) { 765 return ssl_hs_error; 766 } 767 768 if (hs->certificate_status_expected) { 769 CBB body, ocsp_response; 770 if (!ssl->method->init_message(ssl, cbb.get(), &body, 771 SSL3_MT_CERTIFICATE_STATUS) || 772 !CBB_add_u8(&body, TLSEXT_STATUSTYPE_ocsp) || 773 !CBB_add_u24_length_prefixed(&body, &ocsp_response) || 774 !CBB_add_bytes(&ocsp_response, 775 CRYPTO_BUFFER_data(ssl->cert->ocsp_response), 776 CRYPTO_BUFFER_len(ssl->cert->ocsp_response)) || 777 !ssl_add_message_cbb(ssl, cbb.get())) { 778 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 779 return ssl_hs_error; 780 } 781 } 782 } 783 784 // Assemble ServerKeyExchange parameters if needed. 785 uint32_t alg_k = hs->new_cipher->algorithm_mkey; 786 uint32_t alg_a = hs->new_cipher->algorithm_auth; 787 if (ssl_cipher_requires_server_key_exchange(hs->new_cipher) || 788 ((alg_a & SSL_aPSK) && ssl->psk_identity_hint)) { 789 790 // Pre-allocate enough room to comfortably fit an ECDHE public key. Prepend 791 // the client and server randoms for the signing transcript. 792 CBB child; 793 if (!CBB_init(cbb.get(), SSL3_RANDOM_SIZE * 2 + 128) || 794 !CBB_add_bytes(cbb.get(), ssl->s3->client_random, SSL3_RANDOM_SIZE) || 795 !CBB_add_bytes(cbb.get(), ssl->s3->server_random, SSL3_RANDOM_SIZE)) { 796 return ssl_hs_error; 797 } 798 799 // PSK ciphers begin with an identity hint. 800 if (alg_a & SSL_aPSK) { 801 size_t len = 802 (ssl->psk_identity_hint == NULL) ? 0 : strlen(ssl->psk_identity_hint); 803 if (!CBB_add_u16_length_prefixed(cbb.get(), &child) || 804 !CBB_add_bytes(&child, (const uint8_t *)ssl->psk_identity_hint, 805 len)) { 806 return ssl_hs_error; 807 } 808 } 809 810 if (alg_k & SSL_kECDHE) { 811 // Determine the group to use. 812 uint16_t group_id; 813 if (!tls1_get_shared_group(hs, &group_id)) { 814 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 815 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE); 816 return ssl_hs_error; 817 } 818 hs->new_session->group_id = group_id; 819 820 // Set up ECDH, generate a key, and emit the public half. 821 hs->key_share = SSLKeyShare::Create(group_id); 822 if (!hs->key_share || 823 !CBB_add_u8(cbb.get(), NAMED_CURVE_TYPE) || 824 !CBB_add_u16(cbb.get(), group_id) || 825 !CBB_add_u8_length_prefixed(cbb.get(), &child) || 826 !hs->key_share->Offer(&child)) { 827 return ssl_hs_error; 828 } 829 } else { 830 assert(alg_k & SSL_kPSK); 831 } 832 833 if (!CBBFinishArray(cbb.get(), &hs->server_params)) { 834 return ssl_hs_error; 835 } 836 } 837 838 hs->state = state_send_server_key_exchange; 839 return ssl_hs_ok; 840} 841 842static enum ssl_hs_wait_t do_send_server_key_exchange(SSL_HANDSHAKE *hs) { 843 SSL *const ssl = hs->ssl; 844 845 if (hs->server_params.size() == 0) { 846 hs->state = state_send_server_hello_done; 847 return ssl_hs_ok; 848 } 849 850 ScopedCBB cbb; 851 CBB body, child; 852 if (!ssl->method->init_message(ssl, cbb.get(), &body, 853 SSL3_MT_SERVER_KEY_EXCHANGE) || 854 // |hs->server_params| contains a prefix for signing. 855 hs->server_params.size() < 2 * SSL3_RANDOM_SIZE || 856 !CBB_add_bytes(&body, hs->server_params.data() + 2 * SSL3_RANDOM_SIZE, 857 hs->server_params.size() - 2 * SSL3_RANDOM_SIZE)) { 858 return ssl_hs_error; 859 } 860 861 // Add a signature. 862 if (ssl_cipher_uses_certificate_auth(hs->new_cipher)) { 863 if (!ssl_has_private_key(ssl)) { 864 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); 865 return ssl_hs_error; 866 } 867 868 // Determine the signature algorithm. 869 uint16_t signature_algorithm; 870 if (!tls1_choose_signature_algorithm(hs, &signature_algorithm)) { 871 return ssl_hs_error; 872 } 873 if (ssl_protocol_version(ssl) >= TLS1_2_VERSION) { 874 if (!CBB_add_u16(&body, signature_algorithm)) { 875 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 876 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); 877 return ssl_hs_error; 878 } 879 } 880 881 // Add space for the signature. 882 const size_t max_sig_len = EVP_PKEY_size(hs->local_pubkey.get()); 883 uint8_t *ptr; 884 if (!CBB_add_u16_length_prefixed(&body, &child) || 885 !CBB_reserve(&child, &ptr, max_sig_len)) { 886 return ssl_hs_error; 887 } 888 889 size_t sig_len; 890 switch (ssl_private_key_sign(hs, ptr, &sig_len, max_sig_len, 891 signature_algorithm, hs->server_params)) { 892 case ssl_private_key_success: 893 if (!CBB_did_write(&child, sig_len)) { 894 return ssl_hs_error; 895 } 896 break; 897 case ssl_private_key_failure: 898 return ssl_hs_error; 899 case ssl_private_key_retry: 900 return ssl_hs_private_key_operation; 901 } 902 } 903 904 if (!ssl_add_message_cbb(ssl, cbb.get())) { 905 return ssl_hs_error; 906 } 907 908 hs->server_params.Reset(); 909 910 hs->state = state_send_server_hello_done; 911 return ssl_hs_ok; 912} 913 914static enum ssl_hs_wait_t do_send_server_hello_done(SSL_HANDSHAKE *hs) { 915 SSL *const ssl = hs->ssl; 916 917 ScopedCBB cbb; 918 CBB body; 919 920 if (hs->cert_request) { 921 CBB cert_types, sigalgs_cbb; 922 if (!ssl->method->init_message(ssl, cbb.get(), &body, 923 SSL3_MT_CERTIFICATE_REQUEST) || 924 !CBB_add_u8_length_prefixed(&body, &cert_types) || 925 !CBB_add_u8(&cert_types, SSL3_CT_RSA_SIGN) || 926 (ssl_protocol_version(ssl) >= TLS1_VERSION && 927 !CBB_add_u8(&cert_types, TLS_CT_ECDSA_SIGN)) || 928 (ssl_protocol_version(ssl) >= TLS1_2_VERSION && 929 (!CBB_add_u16_length_prefixed(&body, &sigalgs_cbb) || 930 !tls12_add_verify_sigalgs(ssl, &sigalgs_cbb))) || 931 !ssl_add_client_CA_list(ssl, &body) || 932 !ssl_add_message_cbb(ssl, cbb.get())) { 933 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 934 return ssl_hs_error; 935 } 936 } 937 938 if (!ssl->method->init_message(ssl, cbb.get(), &body, 939 SSL3_MT_SERVER_HELLO_DONE) || 940 !ssl_add_message_cbb(ssl, cbb.get())) { 941 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 942 return ssl_hs_error; 943 } 944 945 hs->state = state_read_client_certificate; 946 return ssl_hs_flush; 947} 948 949static enum ssl_hs_wait_t do_read_client_certificate(SSL_HANDSHAKE *hs) { 950 SSL *const ssl = hs->ssl; 951 952 if (!hs->cert_request) { 953 hs->state = state_verify_client_certificate; 954 return ssl_hs_ok; 955 } 956 957 SSLMessage msg; 958 if (!ssl->method->get_message(ssl, &msg)) { 959 return ssl_hs_read_message; 960 } 961 962 if (msg.type != SSL3_MT_CERTIFICATE) { 963 if (ssl->version == SSL3_VERSION && 964 msg.type == SSL3_MT_CLIENT_KEY_EXCHANGE) { 965 // In SSL 3.0, the Certificate message is omitted to signal no 966 // certificate. 967 if (ssl->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT) { 968 OPENSSL_PUT_ERROR(SSL, SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE); 969 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE); 970 return ssl_hs_error; 971 } 972 973 // OpenSSL returns X509_V_OK when no certificates are received. This is 974 // classed by them as a bug, but it's assumed by at least NGINX. 975 hs->new_session->verify_result = X509_V_OK; 976 hs->state = state_verify_client_certificate; 977 return ssl_hs_ok; 978 } 979 980 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE); 981 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE); 982 return ssl_hs_error; 983 } 984 985 if (!ssl_hash_message(hs, msg)) { 986 return ssl_hs_error; 987 } 988 989 CBS certificate_msg = msg.body; 990 uint8_t alert = SSL_AD_DECODE_ERROR; 991 UniquePtr<STACK_OF(CRYPTO_BUFFER)> chain; 992 if (!ssl_parse_cert_chain(&alert, &chain, &hs->peer_pubkey, 993 ssl->retain_only_sha256_of_client_certs 994 ? hs->new_session->peer_sha256 995 : NULL, 996 &certificate_msg, ssl->ctx->pool)) { 997 ssl_send_alert(ssl, SSL3_AL_FATAL, alert); 998 return ssl_hs_error; 999 } 1000 sk_CRYPTO_BUFFER_pop_free(hs->new_session->certs, CRYPTO_BUFFER_free); 1001 hs->new_session->certs = chain.release(); 1002 1003 if (CBS_len(&certificate_msg) != 0 || 1004 !ssl->ctx->x509_method->session_cache_objects(hs->new_session.get())) { 1005 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 1006 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); 1007 return ssl_hs_error; 1008 } 1009 1010 if (sk_CRYPTO_BUFFER_num(hs->new_session->certs) == 0) { 1011 // No client certificate so the handshake buffer may be discarded. 1012 hs->transcript.FreeBuffer(); 1013 1014 // In SSL 3.0, sending no certificate is signaled by omitting the 1015 // Certificate message. 1016 if (ssl->version == SSL3_VERSION) { 1017 OPENSSL_PUT_ERROR(SSL, SSL_R_NO_CERTIFICATES_RETURNED); 1018 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE); 1019 return ssl_hs_error; 1020 } 1021 1022 if (ssl->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT) { 1023 // Fail for TLS only if we required a certificate 1024 OPENSSL_PUT_ERROR(SSL, SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE); 1025 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE); 1026 return ssl_hs_error; 1027 } 1028 1029 // OpenSSL returns X509_V_OK when no certificates are received. This is 1030 // classed by them as a bug, but it's assumed by at least NGINX. 1031 hs->new_session->verify_result = X509_V_OK; 1032 } else if (ssl->retain_only_sha256_of_client_certs) { 1033 // The hash will have been filled in. 1034 hs->new_session->peer_sha256_valid = 1; 1035 } 1036 1037 ssl->method->next_message(ssl); 1038 hs->state = state_verify_client_certificate; 1039 return ssl_hs_ok; 1040} 1041 1042static enum ssl_hs_wait_t do_verify_client_certificate(SSL_HANDSHAKE *hs) { 1043 if (sk_CRYPTO_BUFFER_num(hs->new_session->certs) > 0) { 1044 switch (ssl_verify_peer_cert(hs)) { 1045 case ssl_verify_ok: 1046 break; 1047 case ssl_verify_invalid: 1048 return ssl_hs_error; 1049 case ssl_verify_retry: 1050 return ssl_hs_certificate_verify; 1051 } 1052 } 1053 1054 hs->state = state_read_client_key_exchange; 1055 return ssl_hs_ok; 1056} 1057 1058static enum ssl_hs_wait_t do_read_client_key_exchange(SSL_HANDSHAKE *hs) { 1059 SSL *const ssl = hs->ssl; 1060 SSLMessage msg; 1061 if (!ssl->method->get_message(ssl, &msg)) { 1062 return ssl_hs_read_message; 1063 } 1064 1065 if (!ssl_check_message_type(ssl, msg, SSL3_MT_CLIENT_KEY_EXCHANGE)) { 1066 return ssl_hs_error; 1067 } 1068 1069 CBS client_key_exchange = msg.body; 1070 uint32_t alg_k = hs->new_cipher->algorithm_mkey; 1071 uint32_t alg_a = hs->new_cipher->algorithm_auth; 1072 1073 // If using a PSK key exchange, parse the PSK identity. 1074 if (alg_a & SSL_aPSK) { 1075 CBS psk_identity; 1076 1077 // If using PSK, the ClientKeyExchange contains a psk_identity. If PSK, 1078 // then this is the only field in the message. 1079 if (!CBS_get_u16_length_prefixed(&client_key_exchange, &psk_identity) || 1080 ((alg_k & SSL_kPSK) && CBS_len(&client_key_exchange) != 0)) { 1081 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 1082 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); 1083 return ssl_hs_error; 1084 } 1085 1086 if (CBS_len(&psk_identity) > PSK_MAX_IDENTITY_LEN || 1087 CBS_contains_zero_byte(&psk_identity)) { 1088 OPENSSL_PUT_ERROR(SSL, SSL_R_DATA_LENGTH_TOO_LONG); 1089 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); 1090 return ssl_hs_error; 1091 } 1092 1093 if (!CBS_strdup(&psk_identity, &hs->new_session->psk_identity)) { 1094 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); 1095 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); 1096 return ssl_hs_error; 1097 } 1098 } 1099 1100 // Depending on the key exchange method, compute |premaster_secret|. 1101 Array<uint8_t> premaster_secret; 1102 if (alg_k & SSL_kRSA) { 1103 CBS encrypted_premaster_secret; 1104 if (ssl->version > SSL3_VERSION) { 1105 if (!CBS_get_u16_length_prefixed(&client_key_exchange, 1106 &encrypted_premaster_secret) || 1107 CBS_len(&client_key_exchange) != 0) { 1108 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 1109 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); 1110 return ssl_hs_error; 1111 } 1112 } else { 1113 encrypted_premaster_secret = client_key_exchange; 1114 } 1115 1116 // Allocate a buffer large enough for an RSA decryption. 1117 Array<uint8_t> decrypt_buf; 1118 if (!decrypt_buf.Init(EVP_PKEY_size(hs->local_pubkey.get()))) { 1119 return ssl_hs_error; 1120 } 1121 1122 // Decrypt with no padding. PKCS#1 padding will be removed as part of the 1123 // timing-sensitive code below. 1124 size_t decrypt_len; 1125 switch (ssl_private_key_decrypt(hs, decrypt_buf.data(), &decrypt_len, 1126 decrypt_buf.size(), 1127 encrypted_premaster_secret)) { 1128 case ssl_private_key_success: 1129 break; 1130 case ssl_private_key_failure: 1131 return ssl_hs_error; 1132 case ssl_private_key_retry: 1133 return ssl_hs_private_key_operation; 1134 } 1135 1136 if (decrypt_len != decrypt_buf.size()) { 1137 OPENSSL_PUT_ERROR(SSL, SSL_R_DECRYPTION_FAILED); 1138 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR); 1139 return ssl_hs_error; 1140 } 1141 1142 // Prepare a random premaster, to be used on invalid padding. See RFC 5246, 1143 // section 7.4.7.1. 1144 if (!premaster_secret.Init(SSL_MAX_MASTER_KEY_LENGTH) || 1145 !RAND_bytes(premaster_secret.data(), premaster_secret.size())) { 1146 return ssl_hs_error; 1147 } 1148 1149 // The smallest padded premaster is 11 bytes of overhead. Small keys are 1150 // publicly invalid. 1151 if (decrypt_len < 11 + premaster_secret.size()) { 1152 OPENSSL_PUT_ERROR(SSL, SSL_R_DECRYPTION_FAILED); 1153 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR); 1154 return ssl_hs_error; 1155 } 1156 1157 // Check the padding. See RFC 3447, section 7.2.2. 1158 size_t padding_len = decrypt_len - premaster_secret.size(); 1159 uint8_t good = constant_time_eq_int_8(decrypt_buf[0], 0) & 1160 constant_time_eq_int_8(decrypt_buf[1], 2); 1161 for (size_t i = 2; i < padding_len - 1; i++) { 1162 good &= ~constant_time_is_zero_8(decrypt_buf[i]); 1163 } 1164 good &= constant_time_is_zero_8(decrypt_buf[padding_len - 1]); 1165 1166 // The premaster secret must begin with |client_version|. This too must be 1167 // checked in constant time (http://eprint.iacr.org/2003/052/). 1168 good &= constant_time_eq_8(decrypt_buf[padding_len], 1169 (unsigned)(hs->client_version >> 8)); 1170 good &= constant_time_eq_8(decrypt_buf[padding_len + 1], 1171 (unsigned)(hs->client_version & 0xff)); 1172 1173 // Select, in constant time, either the decrypted premaster or the random 1174 // premaster based on |good|. 1175 for (size_t i = 0; i < premaster_secret.size(); i++) { 1176 premaster_secret[i] = constant_time_select_8( 1177 good, decrypt_buf[padding_len + i], premaster_secret[i]); 1178 } 1179 } else if (alg_k & SSL_kECDHE) { 1180 // Parse the ClientKeyExchange. 1181 CBS peer_key; 1182 if (!CBS_get_u8_length_prefixed(&client_key_exchange, &peer_key) || 1183 CBS_len(&client_key_exchange) != 0) { 1184 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 1185 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); 1186 return ssl_hs_error; 1187 } 1188 1189 // Compute the premaster. 1190 uint8_t alert = SSL_AD_DECODE_ERROR; 1191 if (!hs->key_share->Finish(&premaster_secret, &alert, peer_key)) { 1192 ssl_send_alert(ssl, SSL3_AL_FATAL, alert); 1193 return ssl_hs_error; 1194 } 1195 1196 // The key exchange state may now be discarded. 1197 hs->key_share.reset(); 1198 } else if (!(alg_k & SSL_kPSK)) { 1199 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 1200 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE); 1201 return ssl_hs_error; 1202 } 1203 1204 // For a PSK cipher suite, the actual pre-master secret is combined with the 1205 // pre-shared key. 1206 if (alg_a & SSL_aPSK) { 1207 if (ssl->psk_server_callback == NULL) { 1208 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 1209 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); 1210 return ssl_hs_error; 1211 } 1212 1213 // Look up the key for the identity. 1214 uint8_t psk[PSK_MAX_PSK_LEN]; 1215 unsigned psk_len = ssl->psk_server_callback( 1216 ssl, hs->new_session->psk_identity, psk, sizeof(psk)); 1217 if (psk_len > PSK_MAX_PSK_LEN) { 1218 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); 1219 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); 1220 return ssl_hs_error; 1221 } else if (psk_len == 0) { 1222 // PSK related to the given identity not found. 1223 OPENSSL_PUT_ERROR(SSL, SSL_R_PSK_IDENTITY_NOT_FOUND); 1224 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNKNOWN_PSK_IDENTITY); 1225 return ssl_hs_error; 1226 } 1227 1228 if (alg_k & SSL_kPSK) { 1229 // In plain PSK, other_secret is a block of 0s with the same length as the 1230 // pre-shared key. 1231 if (!premaster_secret.Init(psk_len)) { 1232 return ssl_hs_error; 1233 } 1234 OPENSSL_memset(premaster_secret.data(), 0, premaster_secret.size()); 1235 } 1236 1237 ScopedCBB new_premaster; 1238 CBB child; 1239 if (!CBB_init(new_premaster.get(), 1240 2 + psk_len + 2 + premaster_secret.size()) || 1241 !CBB_add_u16_length_prefixed(new_premaster.get(), &child) || 1242 !CBB_add_bytes(&child, premaster_secret.data(), 1243 premaster_secret.size()) || 1244 !CBB_add_u16_length_prefixed(new_premaster.get(), &child) || 1245 !CBB_add_bytes(&child, psk, psk_len) || 1246 !CBBFinishArray(new_premaster.get(), &premaster_secret)) { 1247 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); 1248 return ssl_hs_error; 1249 } 1250 } 1251 1252 if (!ssl_hash_message(hs, msg)) { 1253 return ssl_hs_error; 1254 } 1255 1256 // Compute the master secret. 1257 hs->new_session->master_key_length = tls1_generate_master_secret( 1258 hs, hs->new_session->master_key, premaster_secret); 1259 if (hs->new_session->master_key_length == 0) { 1260 return ssl_hs_error; 1261 } 1262 hs->new_session->extended_master_secret = hs->extended_master_secret; 1263 1264 ssl->method->next_message(ssl); 1265 hs->state = state_read_client_certificate_verify; 1266 return ssl_hs_ok; 1267} 1268 1269static enum ssl_hs_wait_t do_read_client_certificate_verify(SSL_HANDSHAKE *hs) { 1270 SSL *const ssl = hs->ssl; 1271 1272 // Only RSA and ECDSA client certificates are supported, so a 1273 // CertificateVerify is required if and only if there's a client certificate. 1274 if (!hs->peer_pubkey) { 1275 hs->transcript.FreeBuffer(); 1276 hs->state = state_read_change_cipher_spec; 1277 return ssl_hs_ok; 1278 } 1279 1280 SSLMessage msg; 1281 if (!ssl->method->get_message(ssl, &msg)) { 1282 return ssl_hs_read_message; 1283 } 1284 1285 if (!ssl_check_message_type(ssl, msg, SSL3_MT_CERTIFICATE_VERIFY)) { 1286 return ssl_hs_error; 1287 } 1288 1289 CBS certificate_verify = msg.body, signature; 1290 1291 // Determine the signature algorithm. 1292 uint16_t signature_algorithm = 0; 1293 if (ssl_protocol_version(ssl) >= TLS1_2_VERSION) { 1294 if (!CBS_get_u16(&certificate_verify, &signature_algorithm)) { 1295 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 1296 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); 1297 return ssl_hs_error; 1298 } 1299 uint8_t alert = SSL_AD_DECODE_ERROR; 1300 if (!tls12_check_peer_sigalg(ssl, &alert, signature_algorithm)) { 1301 ssl_send_alert(ssl, SSL3_AL_FATAL, alert); 1302 return ssl_hs_error; 1303 } 1304 hs->new_session->peer_signature_algorithm = signature_algorithm; 1305 } else if (!tls1_get_legacy_signature_algorithm(&signature_algorithm, 1306 hs->peer_pubkey.get())) { 1307 OPENSSL_PUT_ERROR(SSL, SSL_R_PEER_ERROR_UNSUPPORTED_CERTIFICATE_TYPE); 1308 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNSUPPORTED_CERTIFICATE); 1309 return ssl_hs_error; 1310 } 1311 1312 // Parse and verify the signature. 1313 if (!CBS_get_u16_length_prefixed(&certificate_verify, &signature) || 1314 CBS_len(&certificate_verify) != 0) { 1315 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 1316 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); 1317 return ssl_hs_error; 1318 } 1319 1320 bool sig_ok; 1321 // The SSL3 construction for CertificateVerify does not decompose into a 1322 // single final digest and signature, and must be special-cased. 1323 if (ssl_protocol_version(ssl) == SSL3_VERSION) { 1324 uint8_t digest[EVP_MAX_MD_SIZE]; 1325 size_t digest_len; 1326 if (!hs->transcript.GetSSL3CertVerifyHash( 1327 digest, &digest_len, hs->new_session.get(), signature_algorithm)) { 1328 return ssl_hs_error; 1329 } 1330 1331 UniquePtr<EVP_PKEY_CTX> pctx( 1332 EVP_PKEY_CTX_new(hs->peer_pubkey.get(), nullptr)); 1333 sig_ok = pctx && 1334 EVP_PKEY_verify_init(pctx.get()) && 1335 EVP_PKEY_verify(pctx.get(), CBS_data(&signature), 1336 CBS_len(&signature), digest, digest_len); 1337 } else { 1338 sig_ok = 1339 ssl_public_key_verify(ssl, signature, signature_algorithm, 1340 hs->peer_pubkey.get(), hs->transcript.buffer()); 1341 } 1342 1343#if defined(BORINGSSL_UNSAFE_FUZZER_MODE) 1344 sig_ok = true; 1345 ERR_clear_error(); 1346#endif 1347 if (!sig_ok) { 1348 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SIGNATURE); 1349 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR); 1350 return ssl_hs_error; 1351 } 1352 1353 // The handshake buffer is no longer necessary, and we may hash the current 1354 // message. 1355 hs->transcript.FreeBuffer(); 1356 if (!ssl_hash_message(hs, msg)) { 1357 return ssl_hs_error; 1358 } 1359 1360 ssl->method->next_message(ssl); 1361 hs->state = state_read_change_cipher_spec; 1362 return ssl_hs_ok; 1363} 1364 1365static enum ssl_hs_wait_t do_read_change_cipher_spec(SSL_HANDSHAKE *hs) { 1366 hs->state = state_process_change_cipher_spec; 1367 return ssl_hs_read_change_cipher_spec; 1368} 1369 1370static enum ssl_hs_wait_t do_process_change_cipher_spec(SSL_HANDSHAKE *hs) { 1371 if (!tls1_change_cipher_state(hs, evp_aead_open)) { 1372 return ssl_hs_error; 1373 } 1374 1375 hs->state = state_read_next_proto; 1376 return ssl_hs_ok; 1377} 1378 1379static enum ssl_hs_wait_t do_read_next_proto(SSL_HANDSHAKE *hs) { 1380 SSL *const ssl = hs->ssl; 1381 1382 if (!hs->next_proto_neg_seen) { 1383 hs->state = state_read_channel_id; 1384 return ssl_hs_ok; 1385 } 1386 1387 SSLMessage msg; 1388 if (!ssl->method->get_message(ssl, &msg)) { 1389 return ssl_hs_read_message; 1390 } 1391 1392 if (!ssl_check_message_type(ssl, msg, SSL3_MT_NEXT_PROTO) || 1393 !ssl_hash_message(hs, msg)) { 1394 return ssl_hs_error; 1395 } 1396 1397 CBS next_protocol = msg.body, selected_protocol, padding; 1398 if (!CBS_get_u8_length_prefixed(&next_protocol, &selected_protocol) || 1399 !CBS_get_u8_length_prefixed(&next_protocol, &padding) || 1400 CBS_len(&next_protocol) != 0) { 1401 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); 1402 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); 1403 return ssl_hs_error; 1404 } 1405 1406 if (!ssl->s3->next_proto_negotiated.CopyFrom(selected_protocol)) { 1407 return ssl_hs_error; 1408 } 1409 1410 ssl->method->next_message(ssl); 1411 hs->state = state_read_channel_id; 1412 return ssl_hs_ok; 1413} 1414 1415static enum ssl_hs_wait_t do_read_channel_id(SSL_HANDSHAKE *hs) { 1416 SSL *const ssl = hs->ssl; 1417 1418 if (!ssl->s3->tlsext_channel_id_valid) { 1419 hs->state = state_read_client_finished; 1420 return ssl_hs_ok; 1421 } 1422 1423 SSLMessage msg; 1424 if (!ssl->method->get_message(ssl, &msg)) { 1425 return ssl_hs_read_message; 1426 } 1427 1428 if (!ssl_check_message_type(ssl, msg, SSL3_MT_CHANNEL_ID) || 1429 !tls1_verify_channel_id(hs, msg) || 1430 !ssl_hash_message(hs, msg)) { 1431 return ssl_hs_error; 1432 } 1433 1434 ssl->method->next_message(ssl); 1435 hs->state = state_read_client_finished; 1436 return ssl_hs_ok; 1437} 1438 1439static enum ssl_hs_wait_t do_read_client_finished(SSL_HANDSHAKE *hs) { 1440 SSL *const ssl = hs->ssl; 1441 enum ssl_hs_wait_t wait = ssl_get_finished(hs); 1442 if (wait != ssl_hs_ok) { 1443 return wait; 1444 } 1445 1446 if (ssl->session != NULL) { 1447 hs->state = state_finish_server_handshake; 1448 } else { 1449 hs->state = state_send_server_finished; 1450 } 1451 1452 // If this is a full handshake with ChannelID then record the handshake 1453 // hashes in |hs->new_session| in case we need them to verify a 1454 // ChannelID signature on a resumption of this session in the future. 1455 if (ssl->session == NULL && ssl->s3->tlsext_channel_id_valid && 1456 !tls1_record_handshake_hashes_for_channel_id(hs)) { 1457 return ssl_hs_error; 1458 } 1459 1460 return ssl_hs_ok; 1461} 1462 1463static enum ssl_hs_wait_t do_send_server_finished(SSL_HANDSHAKE *hs) { 1464 SSL *const ssl = hs->ssl; 1465 1466 if (hs->ticket_expected) { 1467 const SSL_SESSION *session; 1468 UniquePtr<SSL_SESSION> session_copy; 1469 if (ssl->session == NULL) { 1470 // Fix the timeout to measure from the ticket issuance time. 1471 ssl_session_rebase_time(ssl, hs->new_session.get()); 1472 session = hs->new_session.get(); 1473 } else { 1474 // We are renewing an existing session. Duplicate the session to adjust 1475 // the timeout. 1476 session_copy = SSL_SESSION_dup(ssl->session, SSL_SESSION_INCLUDE_NONAUTH); 1477 if (!session_copy) { 1478 return ssl_hs_error; 1479 } 1480 1481 ssl_session_rebase_time(ssl, session_copy.get()); 1482 session = session_copy.get(); 1483 } 1484 1485 ScopedCBB cbb; 1486 CBB body, ticket; 1487 if (!ssl->method->init_message(ssl, cbb.get(), &body, 1488 SSL3_MT_NEW_SESSION_TICKET) || 1489 !CBB_add_u32(&body, session->timeout) || 1490 !CBB_add_u16_length_prefixed(&body, &ticket) || 1491 !ssl_encrypt_ticket(ssl, &ticket, session) || 1492 !ssl_add_message_cbb(ssl, cbb.get())) { 1493 return ssl_hs_error; 1494 } 1495 } 1496 1497 if (!ssl->method->add_change_cipher_spec(ssl) || 1498 !tls1_change_cipher_state(hs, evp_aead_seal) || 1499 !ssl_send_finished(hs)) { 1500 return ssl_hs_error; 1501 } 1502 1503 if (ssl->session != NULL) { 1504 hs->state = state_read_change_cipher_spec; 1505 } else { 1506 hs->state = state_finish_server_handshake; 1507 } 1508 return ssl_hs_flush; 1509} 1510 1511static enum ssl_hs_wait_t do_finish_server_handshake(SSL_HANDSHAKE *hs) { 1512 SSL *const ssl = hs->ssl; 1513 1514 ssl->method->on_handshake_complete(ssl); 1515 1516 // If we aren't retaining peer certificates then we can discard it now. 1517 if (hs->new_session != NULL && ssl->retain_only_sha256_of_client_certs) { 1518 sk_CRYPTO_BUFFER_pop_free(hs->new_session->certs, CRYPTO_BUFFER_free); 1519 hs->new_session->certs = NULL; 1520 ssl->ctx->x509_method->session_clear(hs->new_session.get()); 1521 } 1522 1523 if (ssl->session != NULL) { 1524 SSL_SESSION_up_ref(ssl->session); 1525 ssl->s3->established_session.reset(ssl->session); 1526 } else { 1527 ssl->s3->established_session = std::move(hs->new_session); 1528 ssl->s3->established_session->not_resumable = 0; 1529 } 1530 1531 hs->handshake_finalized = true; 1532 ssl->s3->initial_handshake_complete = true; 1533 ssl_update_cache(hs, SSL_SESS_CACHE_SERVER); 1534 1535 hs->state = state_done; 1536 return ssl_hs_ok; 1537} 1538 1539enum ssl_hs_wait_t ssl_server_handshake(SSL_HANDSHAKE *hs) { 1540 while (hs->state != state_done) { 1541 enum ssl_hs_wait_t ret = ssl_hs_error; 1542 enum ssl_server_hs_state_t state = 1543 static_cast<enum ssl_server_hs_state_t>(hs->state); 1544 switch (state) { 1545 case state_start_accept: 1546 ret = do_start_accept(hs); 1547 break; 1548 case state_read_client_hello: 1549 ret = do_read_client_hello(hs); 1550 break; 1551 case state_select_certificate: 1552 ret = do_select_certificate(hs); 1553 break; 1554 case state_tls13: 1555 ret = do_tls13(hs); 1556 break; 1557 case state_select_parameters: 1558 ret = do_select_parameters(hs); 1559 break; 1560 case state_send_server_hello: 1561 ret = do_send_server_hello(hs); 1562 break; 1563 case state_send_server_certificate: 1564 ret = do_send_server_certificate(hs); 1565 break; 1566 case state_send_server_key_exchange: 1567 ret = do_send_server_key_exchange(hs); 1568 break; 1569 case state_send_server_hello_done: 1570 ret = do_send_server_hello_done(hs); 1571 break; 1572 case state_read_client_certificate: 1573 ret = do_read_client_certificate(hs); 1574 break; 1575 case state_verify_client_certificate: 1576 ret = do_verify_client_certificate(hs); 1577 break; 1578 case state_read_client_key_exchange: 1579 ret = do_read_client_key_exchange(hs); 1580 break; 1581 case state_read_client_certificate_verify: 1582 ret = do_read_client_certificate_verify(hs); 1583 break; 1584 case state_read_change_cipher_spec: 1585 ret = do_read_change_cipher_spec(hs); 1586 break; 1587 case state_process_change_cipher_spec: 1588 ret = do_process_change_cipher_spec(hs); 1589 break; 1590 case state_read_next_proto: 1591 ret = do_read_next_proto(hs); 1592 break; 1593 case state_read_channel_id: 1594 ret = do_read_channel_id(hs); 1595 break; 1596 case state_read_client_finished: 1597 ret = do_read_client_finished(hs); 1598 break; 1599 case state_send_server_finished: 1600 ret = do_send_server_finished(hs); 1601 break; 1602 case state_finish_server_handshake: 1603 ret = do_finish_server_handshake(hs); 1604 break; 1605 case state_done: 1606 ret = ssl_hs_ok; 1607 break; 1608 } 1609 1610 if (hs->state != state) { 1611 ssl_do_info_callback(hs->ssl, SSL_CB_ACCEPT_LOOP, 1); 1612 } 1613 1614 if (ret != ssl_hs_ok) { 1615 return ret; 1616 } 1617 } 1618 1619 ssl_do_info_callback(hs->ssl, SSL_CB_HANDSHAKE_DONE, 1); 1620 return ssl_hs_ok; 1621} 1622 1623const char *ssl_server_handshake_state(SSL_HANDSHAKE *hs) { 1624 enum ssl_server_hs_state_t state = 1625 static_cast<enum ssl_server_hs_state_t>(hs->state); 1626 switch (state) { 1627 case state_start_accept: 1628 return "TLS server start_accept"; 1629 case state_read_client_hello: 1630 return "TLS server read_client_hello"; 1631 case state_select_certificate: 1632 return "TLS server select_certificate"; 1633 case state_tls13: 1634 return tls13_server_handshake_state(hs); 1635 case state_select_parameters: 1636 return "TLS server select_parameters"; 1637 case state_send_server_hello: 1638 return "TLS server send_server_hello"; 1639 case state_send_server_certificate: 1640 return "TLS server send_server_certificate"; 1641 case state_send_server_key_exchange: 1642 return "TLS server send_server_key_exchange"; 1643 case state_send_server_hello_done: 1644 return "TLS server send_server_hello_done"; 1645 case state_read_client_certificate: 1646 return "TLS server read_client_certificate"; 1647 case state_verify_client_certificate: 1648 return "TLS server verify_client_certificate"; 1649 case state_read_client_key_exchange: 1650 return "TLS server read_client_key_exchange"; 1651 case state_read_client_certificate_verify: 1652 return "TLS server read_client_certificate_verify"; 1653 case state_read_change_cipher_spec: 1654 return "TLS server read_change_cipher_spec"; 1655 case state_process_change_cipher_spec: 1656 return "TLS server process_change_cipher_spec"; 1657 case state_read_next_proto: 1658 return "TLS server read_next_proto"; 1659 case state_read_channel_id: 1660 return "TLS server read_channel_id"; 1661 case state_read_client_finished: 1662 return "TLS server read_client_finished"; 1663 case state_send_server_finished: 1664 return "TLS server send_server_finished"; 1665 case state_finish_server_handshake: 1666 return "TLS server finish_server_handshake"; 1667 case state_done: 1668 return "TLS server done"; 1669 } 1670 1671 return "TLS server unknown"; 1672} 1673 1674} 1675