ssl_tlsext.c revision 1.53
1/* $OpenBSD: ssl_tlsext.c,v 1.53 2020/01/22 10:36:57 tb Exp $ */ 2/* 3 * Copyright (c) 2016, 2017, 2019 Joel Sing <jsing@openbsd.org> 4 * Copyright (c) 2017 Doug Hogan <doug@openbsd.org> 5 * Copyright (c) 2018-2019 Bob Beck <beck@openbsd.org> 6 * 7 * Permission to use, copy, modify, and distribute this software for any 8 * purpose with or without fee is hereby granted, provided that the above 9 * copyright notice and this permission notice appear in all copies. 10 * 11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 18 */ 19#include <openssl/curve25519.h> 20#include <openssl/ocsp.h> 21 22#include "ssl_locl.h" 23 24#include "bytestring.h" 25#include "ssl_sigalgs.h" 26#include "ssl_tlsext.h" 27 28/* 29 * Supported Application-Layer Protocol Negotiation - RFC 7301 30 */ 31 32int 33tlsext_alpn_client_needs(SSL *s) 34{ 35 /* ALPN protos have been specified and this is the initial handshake */ 36 return s->internal->alpn_client_proto_list != NULL && 37 S3I(s)->tmp.finish_md_len == 0; 38} 39 40int 41tlsext_alpn_client_build(SSL *s, CBB *cbb) 42{ 43 CBB protolist; 44 45 if (!CBB_add_u16_length_prefixed(cbb, &protolist)) 46 return 0; 47 48 if (!CBB_add_bytes(&protolist, s->internal->alpn_client_proto_list, 49 s->internal->alpn_client_proto_list_len)) 50 return 0; 51 52 if (!CBB_flush(cbb)) 53 return 0; 54 55 return 1; 56} 57 58int 59tlsext_alpn_server_parse(SSL *s, CBS *cbs, int *alert) 60{ 61 CBS proto_name_list, alpn; 62 const unsigned char *selected; 63 unsigned char selected_len; 64 int r; 65 66 if (!CBS_get_u16_length_prefixed(cbs, &alpn)) 67 goto err; 68 if (CBS_len(&alpn) < 2) 69 goto err; 70 if (CBS_len(cbs) != 0) 71 goto err; 72 73 CBS_dup(&alpn, &proto_name_list); 74 while (CBS_len(&proto_name_list) > 0) { 75 CBS proto_name; 76 77 if (!CBS_get_u8_length_prefixed(&proto_name_list, &proto_name)) 78 goto err; 79 if (CBS_len(&proto_name) == 0) 80 goto err; 81 } 82 83 if (s->ctx->internal->alpn_select_cb == NULL) 84 return 1; 85 86 r = s->ctx->internal->alpn_select_cb(s, &selected, &selected_len, 87 CBS_data(&alpn), CBS_len(&alpn), 88 s->ctx->internal->alpn_select_cb_arg); 89 if (r == SSL_TLSEXT_ERR_OK) { 90 free(S3I(s)->alpn_selected); 91 if ((S3I(s)->alpn_selected = malloc(selected_len)) == NULL) { 92 *alert = SSL_AD_INTERNAL_ERROR; 93 return 0; 94 } 95 memcpy(S3I(s)->alpn_selected, selected, selected_len); 96 S3I(s)->alpn_selected_len = selected_len; 97 } 98 99 return 1; 100 101 err: 102 *alert = SSL_AD_DECODE_ERROR; 103 return 0; 104} 105 106int 107tlsext_alpn_server_needs(SSL *s) 108{ 109 return S3I(s)->alpn_selected != NULL; 110} 111 112int 113tlsext_alpn_server_build(SSL *s, CBB *cbb) 114{ 115 CBB list, selected; 116 117 if (!CBB_add_u16_length_prefixed(cbb, &list)) 118 return 0; 119 120 if (!CBB_add_u8_length_prefixed(&list, &selected)) 121 return 0; 122 123 if (!CBB_add_bytes(&selected, S3I(s)->alpn_selected, 124 S3I(s)->alpn_selected_len)) 125 return 0; 126 127 if (!CBB_flush(cbb)) 128 return 0; 129 130 return 1; 131} 132 133int 134tlsext_alpn_client_parse(SSL *s, CBS *cbs, int *alert) 135{ 136 CBS list, proto; 137 138 if (s->internal->alpn_client_proto_list == NULL) { 139 *alert = TLS1_AD_UNSUPPORTED_EXTENSION; 140 return 0; 141 } 142 143 if (!CBS_get_u16_length_prefixed(cbs, &list)) 144 goto err; 145 if (CBS_len(cbs) != 0) 146 goto err; 147 148 if (!CBS_get_u8_length_prefixed(&list, &proto)) 149 goto err; 150 151 if (CBS_len(&list) != 0) 152 goto err; 153 if (CBS_len(&proto) == 0) 154 goto err; 155 156 if (!CBS_stow(&proto, &(S3I(s)->alpn_selected), 157 &(S3I(s)->alpn_selected_len))) 158 goto err; 159 160 return 1; 161 162 err: 163 *alert = TLS1_AD_DECODE_ERROR; 164 return 0; 165} 166 167/* 168 * Supported Groups - RFC 7919 section 2 169 */ 170int 171tlsext_supportedgroups_client_needs(SSL *s) 172{ 173 return ssl_has_ecc_ciphers(s) || 174 (S3I(s)->hs_tls13.max_version >= TLS1_3_VERSION); 175} 176 177int 178tlsext_supportedgroups_client_build(SSL *s, CBB *cbb) 179{ 180 const uint16_t *groups; 181 size_t groups_len; 182 CBB grouplist; 183 int i; 184 185 tls1_get_group_list(s, 0, &groups, &groups_len); 186 if (groups_len == 0) { 187 SSLerror(s, ERR_R_INTERNAL_ERROR); 188 return 0; 189 } 190 191 if (!CBB_add_u16_length_prefixed(cbb, &grouplist)) 192 return 0; 193 194 for (i = 0; i < groups_len; i++) { 195 if (!CBB_add_u16(&grouplist, groups[i])) 196 return 0; 197 } 198 199 if (!CBB_flush(cbb)) 200 return 0; 201 202 return 1; 203} 204 205int 206tlsext_supportedgroups_server_parse(SSL *s, CBS *cbs, int *alert) 207{ 208 CBS grouplist; 209 size_t groups_len; 210 211 if (!CBS_get_u16_length_prefixed(cbs, &grouplist)) 212 goto err; 213 if (CBS_len(cbs) != 0) 214 goto err; 215 216 groups_len = CBS_len(&grouplist); 217 if (groups_len == 0 || groups_len % 2 != 0) 218 goto err; 219 groups_len /= 2; 220 221 if (!s->internal->hit) { 222 uint16_t *groups; 223 int i; 224 225 if (SSI(s)->tlsext_supportedgroups != NULL) 226 goto err; 227 228 if ((groups = reallocarray(NULL, groups_len, 229 sizeof(uint16_t))) == NULL) { 230 *alert = TLS1_AD_INTERNAL_ERROR; 231 return 0; 232 } 233 234 for (i = 0; i < groups_len; i++) { 235 if (!CBS_get_u16(&grouplist, &groups[i])) { 236 free(groups); 237 goto err; 238 } 239 } 240 241 if (CBS_len(&grouplist) != 0) { 242 free(groups); 243 goto err; 244 } 245 246 SSI(s)->tlsext_supportedgroups = groups; 247 SSI(s)->tlsext_supportedgroups_length = groups_len; 248 } 249 250 return 1; 251 252 err: 253 *alert = TLS1_AD_DECODE_ERROR; 254 return 0; 255} 256 257/* This extension is never used by the server. */ 258int 259tlsext_supportedgroups_server_needs(SSL *s) 260{ 261 return 0; 262} 263 264int 265tlsext_supportedgroups_server_build(SSL *s, CBB *cbb) 266{ 267 return 0; 268} 269 270int 271tlsext_supportedgroups_client_parse(SSL *s, CBS *cbs, int *alert) 272{ 273 /* 274 * Servers should not send this extension per the RFC. 275 * 276 * However, certain F5 BIG-IP systems incorrectly send it. This bug is 277 * from at least 2014 but as of 2017, there are still large sites with 278 * this unpatched in production. As a result, we need to currently skip 279 * over the extension and ignore its content: 280 * 281 * https://support.f5.com/csp/article/K37345003 282 */ 283 if (!CBS_skip(cbs, CBS_len(cbs))) { 284 *alert = TLS1_AD_INTERNAL_ERROR; 285 return 0; 286 } 287 288 return 1; 289} 290 291/* 292 * Supported Point Formats Extension - RFC 4492 section 5.1.2 293 */ 294static int 295tlsext_ecpf_build(SSL *s, CBB *cbb) 296{ 297 CBB ecpf; 298 size_t formats_len; 299 const uint8_t *formats; 300 301 tls1_get_formatlist(s, 0, &formats, &formats_len); 302 303 if (formats_len == 0) { 304 SSLerror(s, ERR_R_INTERNAL_ERROR); 305 return 0; 306 } 307 308 if (!CBB_add_u8_length_prefixed(cbb, &ecpf)) 309 return 0; 310 if (!CBB_add_bytes(&ecpf, formats, formats_len)) 311 return 0; 312 if (!CBB_flush(cbb)) 313 return 0; 314 315 return 1; 316} 317 318static int 319tlsext_ecpf_parse(SSL *s, CBS *cbs, int *alert) 320{ 321 CBS ecpf; 322 323 if (!CBS_get_u8_length_prefixed(cbs, &ecpf)) 324 goto err; 325 if (CBS_len(&ecpf) == 0) 326 goto err; 327 if (CBS_len(cbs) != 0) 328 goto err; 329 330 /* Must contain uncompressed (0) */ 331 if (!CBS_contains_zero_byte(&ecpf)) { 332 SSLerror(s, SSL_R_TLS_INVALID_ECPOINTFORMAT_LIST); 333 goto err; 334 } 335 336 if (!s->internal->hit) { 337 if (!CBS_stow(&ecpf, &(SSI(s)->tlsext_ecpointformatlist), 338 &(SSI(s)->tlsext_ecpointformatlist_length))) { 339 *alert = TLS1_AD_INTERNAL_ERROR; 340 return 0; 341 } 342 } 343 344 return 1; 345 346 err: 347 *alert = SSL_AD_DECODE_ERROR; 348 return 0; 349} 350 351int 352tlsext_ecpf_client_needs(SSL *s) 353{ 354 return ssl_has_ecc_ciphers(s); 355} 356 357int 358tlsext_ecpf_client_build(SSL *s, CBB *cbb) 359{ 360 return tlsext_ecpf_build(s, cbb); 361} 362 363int 364tlsext_ecpf_server_parse(SSL *s, CBS *cbs, int *alert) 365{ 366 return tlsext_ecpf_parse(s, cbs, alert); 367} 368 369int 370tlsext_ecpf_server_needs(SSL *s) 371{ 372 if (s->version == DTLS1_VERSION) 373 return 0; 374 375 return ssl_using_ecc_cipher(s); 376} 377 378int 379tlsext_ecpf_server_build(SSL *s, CBB *cbb) 380{ 381 return tlsext_ecpf_build(s, cbb); 382} 383 384int 385tlsext_ecpf_client_parse(SSL *s, CBS *cbs, int *alert) 386{ 387 return tlsext_ecpf_parse(s, cbs, alert); 388} 389 390/* 391 * Renegotiation Indication - RFC 5746. 392 */ 393int 394tlsext_ri_client_needs(SSL *s) 395{ 396 return (s->internal->renegotiate); 397} 398 399int 400tlsext_ri_client_build(SSL *s, CBB *cbb) 401{ 402 CBB reneg; 403 404 if (!CBB_add_u8_length_prefixed(cbb, &reneg)) 405 return 0; 406 if (!CBB_add_bytes(&reneg, S3I(s)->previous_client_finished, 407 S3I(s)->previous_client_finished_len)) 408 return 0; 409 if (!CBB_flush(cbb)) 410 return 0; 411 412 return 1; 413} 414 415int 416tlsext_ri_server_parse(SSL *s, CBS *cbs, int *alert) 417{ 418 CBS reneg; 419 420 if (!CBS_get_u8_length_prefixed(cbs, &reneg)) 421 goto err; 422 if (CBS_len(cbs) != 0) 423 goto err; 424 425 if (!CBS_mem_equal(&reneg, S3I(s)->previous_client_finished, 426 S3I(s)->previous_client_finished_len)) { 427 SSLerror(s, SSL_R_RENEGOTIATION_MISMATCH); 428 *alert = SSL_AD_HANDSHAKE_FAILURE; 429 return 0; 430 } 431 432 S3I(s)->renegotiate_seen = 1; 433 S3I(s)->send_connection_binding = 1; 434 435 return 1; 436 437 err: 438 SSLerror(s, SSL_R_RENEGOTIATION_ENCODING_ERR); 439 *alert = SSL_AD_DECODE_ERROR; 440 return 0; 441} 442 443int 444tlsext_ri_server_needs(SSL *s) 445{ 446 return (S3I(s)->send_connection_binding); 447} 448 449int 450tlsext_ri_server_build(SSL *s, CBB *cbb) 451{ 452 CBB reneg; 453 454 if (!CBB_add_u8_length_prefixed(cbb, &reneg)) 455 return 0; 456 if (!CBB_add_bytes(&reneg, S3I(s)->previous_client_finished, 457 S3I(s)->previous_client_finished_len)) 458 return 0; 459 if (!CBB_add_bytes(&reneg, S3I(s)->previous_server_finished, 460 S3I(s)->previous_server_finished_len)) 461 return 0; 462 if (!CBB_flush(cbb)) 463 return 0; 464 465 return 1; 466} 467 468int 469tlsext_ri_client_parse(SSL *s, CBS *cbs, int *alert) 470{ 471 CBS reneg, prev_client, prev_server; 472 473 /* 474 * Ensure that the previous client and server values are both not 475 * present, or that they are both present. 476 */ 477 if ((S3I(s)->previous_client_finished_len == 0 && 478 S3I(s)->previous_server_finished_len != 0) || 479 (S3I(s)->previous_client_finished_len != 0 && 480 S3I(s)->previous_server_finished_len == 0)) { 481 *alert = TLS1_AD_INTERNAL_ERROR; 482 return 0; 483 } 484 485 if (!CBS_get_u8_length_prefixed(cbs, &reneg)) 486 goto err; 487 if (!CBS_get_bytes(&reneg, &prev_client, 488 S3I(s)->previous_client_finished_len)) 489 goto err; 490 if (!CBS_get_bytes(&reneg, &prev_server, 491 S3I(s)->previous_server_finished_len)) 492 goto err; 493 if (CBS_len(&reneg) != 0) 494 goto err; 495 if (CBS_len(cbs) != 0) 496 goto err; 497 498 if (!CBS_mem_equal(&prev_client, S3I(s)->previous_client_finished, 499 S3I(s)->previous_client_finished_len)) { 500 SSLerror(s, SSL_R_RENEGOTIATION_MISMATCH); 501 *alert = SSL_AD_HANDSHAKE_FAILURE; 502 return 0; 503 } 504 if (!CBS_mem_equal(&prev_server, S3I(s)->previous_server_finished, 505 S3I(s)->previous_server_finished_len)) { 506 SSLerror(s, SSL_R_RENEGOTIATION_MISMATCH); 507 *alert = SSL_AD_HANDSHAKE_FAILURE; 508 return 0; 509 } 510 511 S3I(s)->renegotiate_seen = 1; 512 S3I(s)->send_connection_binding = 1; 513 514 return 1; 515 516 err: 517 SSLerror(s, SSL_R_RENEGOTIATION_ENCODING_ERR); 518 *alert = SSL_AD_DECODE_ERROR; 519 return 0; 520} 521 522/* 523 * Signature Algorithms - RFC 5246 section 7.4.1.4.1. 524 */ 525int 526tlsext_sigalgs_client_needs(SSL *s) 527{ 528 return (TLS1_get_client_version(s) >= TLS1_2_VERSION); 529} 530 531int 532tlsext_sigalgs_client_build(SSL *s, CBB *cbb) 533{ 534 uint16_t *tls_sigalgs = tls12_sigalgs; 535 size_t tls_sigalgs_len = tls12_sigalgs_len; 536 CBB sigalgs; 537 538 if (TLS1_get_client_version(s) >= TLS1_3_VERSION && 539 S3I(s)->hs_tls13.min_version >= TLS1_3_VERSION) { 540 tls_sigalgs = tls13_sigalgs; 541 tls_sigalgs_len = tls13_sigalgs_len; 542 } 543 544 if (!CBB_add_u16_length_prefixed(cbb, &sigalgs)) 545 return 0; 546 547 if (!ssl_sigalgs_build(&sigalgs, tls_sigalgs, tls_sigalgs_len)) 548 return 0; 549 550 if (!CBB_flush(cbb)) 551 return 0; 552 553 return 1; 554} 555 556int 557tlsext_sigalgs_server_parse(SSL *s, CBS *cbs, int *alert) 558{ 559 CBS sigalgs; 560 561 if (!CBS_get_u16_length_prefixed(cbs, &sigalgs)) 562 return 0; 563 if (CBS_len(&sigalgs) % 2 != 0 || CBS_len(&sigalgs) > 64) 564 return 0; 565 if (!CBS_stow(&sigalgs, &S3I(s)->hs.sigalgs, &S3I(s)->hs.sigalgs_len)) 566 return 0; 567 568 return 1; 569} 570 571int 572tlsext_sigalgs_server_needs(SSL *s) 573{ 574 return 0; 575} 576 577int 578tlsext_sigalgs_server_build(SSL *s, CBB *cbb) 579{ 580 return 0; 581} 582 583int 584tlsext_sigalgs_client_parse(SSL *s, CBS *cbs, int *alert) 585{ 586 /* As per the RFC, servers must not send this extension. */ 587 return 0; 588} 589 590/* 591 * Server Name Indication - RFC 6066, section 3. 592 */ 593int 594tlsext_sni_client_needs(SSL *s) 595{ 596 return (s->tlsext_hostname != NULL); 597} 598 599int 600tlsext_sni_client_build(SSL *s, CBB *cbb) 601{ 602 CBB server_name_list, host_name; 603 604 if (!CBB_add_u16_length_prefixed(cbb, &server_name_list)) 605 return 0; 606 if (!CBB_add_u8(&server_name_list, TLSEXT_NAMETYPE_host_name)) 607 return 0; 608 if (!CBB_add_u16_length_prefixed(&server_name_list, &host_name)) 609 return 0; 610 if (!CBB_add_bytes(&host_name, (const uint8_t *)s->tlsext_hostname, 611 strlen(s->tlsext_hostname))) 612 return 0; 613 if (!CBB_flush(cbb)) 614 return 0; 615 616 return 1; 617} 618 619int 620tlsext_sni_server_parse(SSL *s, CBS *cbs, int *alert) 621{ 622 CBS server_name_list, host_name; 623 uint8_t name_type; 624 625 if (!CBS_get_u16_length_prefixed(cbs, &server_name_list)) 626 goto err; 627 628 /* 629 * RFC 6066 section 3 forbids multiple host names with the same type. 630 * Additionally, only one type (host_name) is specified. 631 */ 632 if (!CBS_get_u8(&server_name_list, &name_type)) 633 goto err; 634 if (name_type != TLSEXT_NAMETYPE_host_name) 635 goto err; 636 637 if (!CBS_get_u16_length_prefixed(&server_name_list, &host_name)) 638 goto err; 639 if (CBS_len(&host_name) == 0 || 640 CBS_len(&host_name) > TLSEXT_MAXLEN_host_name || 641 CBS_contains_zero_byte(&host_name)) { 642 *alert = TLS1_AD_UNRECOGNIZED_NAME; 643 return 0; 644 } 645 646 if (s->internal->hit) { 647 if (s->session->tlsext_hostname == NULL) { 648 *alert = TLS1_AD_UNRECOGNIZED_NAME; 649 return 0; 650 } 651 if (!CBS_mem_equal(&host_name, s->session->tlsext_hostname, 652 strlen(s->session->tlsext_hostname))) { 653 *alert = TLS1_AD_UNRECOGNIZED_NAME; 654 return 0; 655 } 656 } else { 657 if (s->session->tlsext_hostname != NULL) 658 goto err; 659 if (!CBS_strdup(&host_name, &s->session->tlsext_hostname)) { 660 *alert = TLS1_AD_INTERNAL_ERROR; 661 return 0; 662 } 663 } 664 665 if (CBS_len(&server_name_list) != 0) 666 goto err; 667 if (CBS_len(cbs) != 0) 668 goto err; 669 670 return 1; 671 672 err: 673 *alert = SSL_AD_DECODE_ERROR; 674 return 0; 675} 676 677int 678tlsext_sni_server_needs(SSL *s) 679{ 680 if (s->internal->hit) 681 return 0; 682 683 return (s->session->tlsext_hostname != NULL); 684} 685 686int 687tlsext_sni_server_build(SSL *s, CBB *cbb) 688{ 689 return 1; 690} 691 692int 693tlsext_sni_client_parse(SSL *s, CBS *cbs, int *alert) 694{ 695 if (s->tlsext_hostname == NULL || CBS_len(cbs) != 0) { 696 *alert = TLS1_AD_UNRECOGNIZED_NAME; 697 return 0; 698 } 699 700 if (s->internal->hit) { 701 if (s->session->tlsext_hostname == NULL) { 702 *alert = TLS1_AD_UNRECOGNIZED_NAME; 703 return 0; 704 } 705 if (strcmp(s->tlsext_hostname, 706 s->session->tlsext_hostname) != 0) { 707 *alert = TLS1_AD_UNRECOGNIZED_NAME; 708 return 0; 709 } 710 } else { 711 if (s->session->tlsext_hostname != NULL) { 712 *alert = SSL_AD_DECODE_ERROR; 713 return 0; 714 } 715 if ((s->session->tlsext_hostname = 716 strdup(s->tlsext_hostname)) == NULL) { 717 *alert = TLS1_AD_INTERNAL_ERROR; 718 return 0; 719 } 720 } 721 722 return 1; 723} 724 725 726/* 727 *Certificate Status Request - RFC 6066 section 8. 728 */ 729 730int 731tlsext_ocsp_client_needs(SSL *s) 732{ 733 return (s->tlsext_status_type == TLSEXT_STATUSTYPE_ocsp && 734 s->version != DTLS1_VERSION); 735} 736 737int 738tlsext_ocsp_client_build(SSL *s, CBB *cbb) 739{ 740 CBB respid_list, respid, exts; 741 unsigned char *ext_data; 742 size_t ext_len; 743 int i; 744 745 if (!CBB_add_u8(cbb, TLSEXT_STATUSTYPE_ocsp)) 746 return 0; 747 if (!CBB_add_u16_length_prefixed(cbb, &respid_list)) 748 return 0; 749 for (i = 0; i < sk_OCSP_RESPID_num(s->internal->tlsext_ocsp_ids); i++) { 750 unsigned char *respid_data; 751 OCSP_RESPID *id; 752 size_t id_len; 753 754 if ((id = sk_OCSP_RESPID_value(s->internal->tlsext_ocsp_ids, 755 i)) == NULL) 756 return 0; 757 if ((id_len = i2d_OCSP_RESPID(id, NULL)) == -1) 758 return 0; 759 if (!CBB_add_u16_length_prefixed(&respid_list, &respid)) 760 return 0; 761 if (!CBB_add_space(&respid, &respid_data, id_len)) 762 return 0; 763 if ((i2d_OCSP_RESPID(id, &respid_data)) != id_len) 764 return 0; 765 } 766 if (!CBB_add_u16_length_prefixed(cbb, &exts)) 767 return 0; 768 if ((ext_len = i2d_X509_EXTENSIONS(s->internal->tlsext_ocsp_exts, 769 NULL)) == -1) 770 return 0; 771 if (!CBB_add_space(&exts, &ext_data, ext_len)) 772 return 0; 773 if ((i2d_X509_EXTENSIONS(s->internal->tlsext_ocsp_exts, &ext_data) != 774 ext_len)) 775 return 0; 776 if (!CBB_flush(cbb)) 777 return 0; 778 return 1; 779} 780 781int 782tlsext_ocsp_server_parse(SSL *s, CBS *cbs, int *alert) 783{ 784 int failure = SSL_AD_DECODE_ERROR; 785 CBS respid_list, respid, exts; 786 const unsigned char *p; 787 uint8_t status_type; 788 int ret = 0; 789 790 if (!CBS_get_u8(cbs, &status_type)) 791 goto err; 792 if (status_type != TLSEXT_STATUSTYPE_ocsp) { 793 /* ignore unknown status types */ 794 s->tlsext_status_type = -1; 795 796 if (!CBS_skip(cbs, CBS_len(cbs))) { 797 *alert = TLS1_AD_INTERNAL_ERROR; 798 return 0; 799 } 800 return 1; 801 } 802 s->tlsext_status_type = status_type; 803 if (!CBS_get_u16_length_prefixed(cbs, &respid_list)) 804 goto err; 805 806 /* XXX */ 807 sk_OCSP_RESPID_pop_free(s->internal->tlsext_ocsp_ids, OCSP_RESPID_free); 808 s->internal->tlsext_ocsp_ids = NULL; 809 if (CBS_len(&respid_list) > 0) { 810 s->internal->tlsext_ocsp_ids = sk_OCSP_RESPID_new_null(); 811 if (s->internal->tlsext_ocsp_ids == NULL) { 812 failure = SSL_AD_INTERNAL_ERROR; 813 goto err; 814 } 815 } 816 817 while (CBS_len(&respid_list) > 0) { 818 OCSP_RESPID *id; 819 820 if (!CBS_get_u16_length_prefixed(&respid_list, &respid)) 821 goto err; 822 p = CBS_data(&respid); 823 if ((id = d2i_OCSP_RESPID(NULL, &p, CBS_len(&respid))) == NULL) 824 goto err; 825 if (!sk_OCSP_RESPID_push(s->internal->tlsext_ocsp_ids, id)) { 826 failure = SSL_AD_INTERNAL_ERROR; 827 OCSP_RESPID_free(id); 828 goto err; 829 } 830 } 831 832 /* Read in request_extensions */ 833 if (!CBS_get_u16_length_prefixed(cbs, &exts)) 834 goto err; 835 if (CBS_len(&exts) > 0) { 836 sk_X509_EXTENSION_pop_free(s->internal->tlsext_ocsp_exts, 837 X509_EXTENSION_free); 838 p = CBS_data(&exts); 839 if ((s->internal->tlsext_ocsp_exts = d2i_X509_EXTENSIONS(NULL, 840 &p, CBS_len(&exts))) == NULL) 841 goto err; 842 } 843 844 /* should be nothing left */ 845 if (CBS_len(cbs) > 0) 846 goto err; 847 848 ret = 1; 849 err: 850 if (ret == 0) 851 *alert = failure; 852 return ret; 853} 854 855int 856tlsext_ocsp_server_needs(SSL *s) 857{ 858 return s->internal->tlsext_status_expected; 859} 860 861int 862tlsext_ocsp_server_build(SSL *s, CBB *cbb) 863{ 864 return 1; 865} 866 867int 868tlsext_ocsp_client_parse(SSL *s, CBS *cbs, int *alert) 869{ 870 if (s->tlsext_status_type == -1) { 871 *alert = TLS1_AD_UNSUPPORTED_EXTENSION; 872 return 0; 873 } 874 /* Set flag to expect CertificateStatus message */ 875 s->internal->tlsext_status_expected = 1; 876 return 1; 877} 878 879/* 880 * SessionTicket extension - RFC 5077 section 3.2 881 */ 882int 883tlsext_sessionticket_client_needs(SSL *s) 884{ 885 /* 886 * Send session ticket extension when enabled and not overridden. 887 * 888 * When renegotiating, send an empty session ticket to indicate support. 889 */ 890 if ((SSL_get_options(s) & SSL_OP_NO_TICKET) != 0) 891 return 0; 892 893 if (s->internal->new_session) 894 return 1; 895 896 if (s->internal->tlsext_session_ticket != NULL && 897 s->internal->tlsext_session_ticket->data == NULL) 898 return 0; 899 900 return 1; 901} 902 903int 904tlsext_sessionticket_client_build(SSL *s, CBB *cbb) 905{ 906 /* 907 * Signal that we support session tickets by sending an empty 908 * extension when renegotiating or no session found. 909 */ 910 if (s->internal->new_session || s->session == NULL) 911 return 1; 912 913 if (s->session->tlsext_tick != NULL) { 914 /* Attempt to resume with an existing session ticket */ 915 if (!CBB_add_bytes(cbb, s->session->tlsext_tick, 916 s->session->tlsext_ticklen)) 917 return 0; 918 919 } else if (s->internal->tlsext_session_ticket != NULL) { 920 /* 921 * Attempt to resume with a custom provided session ticket set 922 * by SSL_set_session_ticket_ext(). 923 */ 924 if (s->internal->tlsext_session_ticket->length > 0) { 925 size_t ticklen = s->internal->tlsext_session_ticket->length; 926 927 if ((s->session->tlsext_tick = malloc(ticklen)) == NULL) 928 return 0; 929 memcpy(s->session->tlsext_tick, 930 s->internal->tlsext_session_ticket->data, 931 ticklen); 932 s->session->tlsext_ticklen = ticklen; 933 934 if (!CBB_add_bytes(cbb, s->session->tlsext_tick, 935 s->session->tlsext_ticklen)) 936 return 0; 937 } 938 } 939 940 if (!CBB_flush(cbb)) 941 return 0; 942 943 return 1; 944} 945 946int 947tlsext_sessionticket_server_parse(SSL *s, CBS *cbs, int *alert) 948{ 949 if (s->internal->tls_session_ticket_ext_cb) { 950 if (!s->internal->tls_session_ticket_ext_cb(s, CBS_data(cbs), 951 (int)CBS_len(cbs), 952 s->internal->tls_session_ticket_ext_cb_arg)) { 953 *alert = TLS1_AD_INTERNAL_ERROR; 954 return 0; 955 } 956 } 957 958 /* We need to signal that this was processed fully */ 959 if (!CBS_skip(cbs, CBS_len(cbs))) { 960 *alert = TLS1_AD_INTERNAL_ERROR; 961 return 0; 962 } 963 964 return 1; 965} 966 967int 968tlsext_sessionticket_server_needs(SSL *s) 969{ 970 return (s->internal->tlsext_ticket_expected && 971 !(SSL_get_options(s) & SSL_OP_NO_TICKET)); 972} 973 974int 975tlsext_sessionticket_server_build(SSL *s, CBB *cbb) 976{ 977 /* Empty ticket */ 978 return 1; 979} 980 981int 982tlsext_sessionticket_client_parse(SSL *s, CBS *cbs, int *alert) 983{ 984 if (s->internal->tls_session_ticket_ext_cb) { 985 if (!s->internal->tls_session_ticket_ext_cb(s, CBS_data(cbs), 986 (int)CBS_len(cbs), 987 s->internal->tls_session_ticket_ext_cb_arg)) { 988 *alert = TLS1_AD_INTERNAL_ERROR; 989 return 0; 990 } 991 } 992 993 if ((SSL_get_options(s) & SSL_OP_NO_TICKET) != 0 || CBS_len(cbs) > 0) { 994 *alert = TLS1_AD_UNSUPPORTED_EXTENSION; 995 return 0; 996 } 997 998 s->internal->tlsext_ticket_expected = 1; 999 1000 return 1; 1001} 1002 1003/* 1004 * DTLS extension for SRTP key establishment - RFC 5764 1005 */ 1006 1007#ifndef OPENSSL_NO_SRTP 1008 1009int 1010tlsext_srtp_client_needs(SSL *s) 1011{ 1012 return SSL_IS_DTLS(s) && SSL_get_srtp_profiles(s) != NULL; 1013} 1014 1015int 1016tlsext_srtp_client_build(SSL *s, CBB *cbb) 1017{ 1018 CBB profiles, mki; 1019 int ct, i; 1020 STACK_OF(SRTP_PROTECTION_PROFILE) *clnt = NULL; 1021 SRTP_PROTECTION_PROFILE *prof; 1022 1023 if ((clnt = SSL_get_srtp_profiles(s)) == NULL) { 1024 SSLerror(s, SSL_R_EMPTY_SRTP_PROTECTION_PROFILE_LIST); 1025 return 0; 1026 } 1027 1028 if ((ct = sk_SRTP_PROTECTION_PROFILE_num(clnt)) < 1) { 1029 SSLerror(s, SSL_R_EMPTY_SRTP_PROTECTION_PROFILE_LIST); 1030 return 0; 1031 } 1032 1033 if (!CBB_add_u16_length_prefixed(cbb, &profiles)) 1034 return 0; 1035 1036 for (i = 0; i < ct; i++) { 1037 if ((prof = sk_SRTP_PROTECTION_PROFILE_value(clnt, i)) == NULL) 1038 return 0; 1039 if (!CBB_add_u16(&profiles, prof->id)) 1040 return 0; 1041 } 1042 1043 if (!CBB_add_u8_length_prefixed(cbb, &mki)) 1044 return 0; 1045 1046 if (!CBB_flush(cbb)) 1047 return 0; 1048 1049 return 1; 1050} 1051 1052int 1053tlsext_srtp_server_parse(SSL *s, CBS *cbs, int *alert) 1054{ 1055 SRTP_PROTECTION_PROFILE *cprof, *sprof; 1056 STACK_OF(SRTP_PROTECTION_PROFILE) *clnt = NULL, *srvr; 1057 int i, j; 1058 int ret; 1059 uint16_t id; 1060 CBS profiles, mki; 1061 1062 ret = 0; 1063 1064 if (!CBS_get_u16_length_prefixed(cbs, &profiles)) 1065 goto err; 1066 if (CBS_len(&profiles) == 0 || CBS_len(&profiles) % 2 != 0) 1067 goto err; 1068 1069 if ((clnt = sk_SRTP_PROTECTION_PROFILE_new_null()) == NULL) 1070 goto err; 1071 1072 while (CBS_len(&profiles) > 0) { 1073 if (!CBS_get_u16(&profiles, &id)) 1074 goto err; 1075 1076 if (!srtp_find_profile_by_num(id, &cprof)) { 1077 if (!sk_SRTP_PROTECTION_PROFILE_push(clnt, cprof)) 1078 goto err; 1079 } 1080 } 1081 1082 if (!CBS_get_u8_length_prefixed(cbs, &mki) || CBS_len(&mki) != 0) { 1083 SSLerror(s, SSL_R_BAD_SRTP_MKI_VALUE); 1084 *alert = SSL_AD_DECODE_ERROR; 1085 goto done; 1086 } 1087 if (CBS_len(cbs) != 0) 1088 goto err; 1089 1090 /* 1091 * Per RFC 5764 section 4.1.1 1092 * 1093 * Find the server preferred profile using the client's list. 1094 * 1095 * The server MUST send a profile if it sends the use_srtp 1096 * extension. If one is not found, it should fall back to the 1097 * negotiated DTLS cipher suite or return a DTLS alert. 1098 */ 1099 if ((srvr = SSL_get_srtp_profiles(s)) == NULL) 1100 goto err; 1101 for (i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(srvr); i++) { 1102 if ((sprof = sk_SRTP_PROTECTION_PROFILE_value(srvr, i)) 1103 == NULL) 1104 goto err; 1105 1106 for (j = 0; j < sk_SRTP_PROTECTION_PROFILE_num(clnt); j++) { 1107 if ((cprof = sk_SRTP_PROTECTION_PROFILE_value(clnt, j)) 1108 == NULL) 1109 goto err; 1110 1111 if (cprof->id == sprof->id) { 1112 s->internal->srtp_profile = sprof; 1113 ret = 1; 1114 goto done; 1115 } 1116 } 1117 } 1118 1119 /* If we didn't find anything, fall back to the negotiated */ 1120 ret = 1; 1121 goto done; 1122 1123 err: 1124 SSLerror(s, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST); 1125 *alert = SSL_AD_DECODE_ERROR; 1126 1127 done: 1128 sk_SRTP_PROTECTION_PROFILE_free(clnt); 1129 return ret; 1130} 1131 1132int 1133tlsext_srtp_server_needs(SSL *s) 1134{ 1135 return SSL_IS_DTLS(s) && SSL_get_selected_srtp_profile(s) != NULL; 1136} 1137 1138int 1139tlsext_srtp_server_build(SSL *s, CBB *cbb) 1140{ 1141 SRTP_PROTECTION_PROFILE *profile; 1142 CBB srtp, mki; 1143 1144 if (!CBB_add_u16_length_prefixed(cbb, &srtp)) 1145 return 0; 1146 1147 if ((profile = SSL_get_selected_srtp_profile(s)) == NULL) 1148 return 0; 1149 1150 if (!CBB_add_u16(&srtp, profile->id)) 1151 return 0; 1152 1153 if (!CBB_add_u8_length_prefixed(cbb, &mki)) 1154 return 0; 1155 1156 if (!CBB_flush(cbb)) 1157 return 0; 1158 1159 return 1; 1160} 1161 1162int 1163tlsext_srtp_client_parse(SSL *s, CBS *cbs, int *alert) 1164{ 1165 STACK_OF(SRTP_PROTECTION_PROFILE) *clnt; 1166 SRTP_PROTECTION_PROFILE *prof; 1167 int i; 1168 uint16_t id; 1169 CBS profile_ids, mki; 1170 1171 if (!CBS_get_u16_length_prefixed(cbs, &profile_ids)) { 1172 SSLerror(s, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST); 1173 goto err; 1174 } 1175 1176 if (!CBS_get_u16(&profile_ids, &id) || CBS_len(&profile_ids) != 0) { 1177 SSLerror(s, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST); 1178 goto err; 1179 } 1180 1181 if (!CBS_get_u8_length_prefixed(cbs, &mki) || CBS_len(&mki) != 0) { 1182 SSLerror(s, SSL_R_BAD_SRTP_MKI_VALUE); 1183 *alert = SSL_AD_ILLEGAL_PARAMETER; 1184 return 0; 1185 } 1186 1187 if ((clnt = SSL_get_srtp_profiles(s)) == NULL) { 1188 SSLerror(s, SSL_R_NO_SRTP_PROFILES); 1189 goto err; 1190 } 1191 1192 for (i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(clnt); i++) { 1193 if ((prof = sk_SRTP_PROTECTION_PROFILE_value(clnt, i)) 1194 == NULL) { 1195 SSLerror(s, SSL_R_NO_SRTP_PROFILES); 1196 goto err; 1197 } 1198 1199 if (prof->id == id) { 1200 s->internal->srtp_profile = prof; 1201 return 1; 1202 } 1203 } 1204 1205 SSLerror(s, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST); 1206 err: 1207 *alert = SSL_AD_DECODE_ERROR; 1208 return 0; 1209} 1210 1211#endif /* OPENSSL_NO_SRTP */ 1212 1213/* 1214 * TLSv1.3 Key Share - RFC 8446 section 4.2.8. 1215 */ 1216int 1217tlsext_keyshare_client_needs(SSL *s) 1218{ 1219 /* XXX once this gets initialized when we get tls13_client.c */ 1220 if (S3I(s)->hs_tls13.max_version == 0) 1221 return 0; 1222 return (!SSL_IS_DTLS(s) && S3I(s)->hs_tls13.max_version >= 1223 TLS1_3_VERSION); 1224} 1225 1226int 1227tlsext_keyshare_client_build(SSL *s, CBB *cbb) 1228{ 1229 uint8_t *public_key = NULL, *private_key = NULL; 1230 CBB client_shares, key_exchange; 1231 1232 /* Generate and provide key shares. */ 1233 if (!CBB_add_u16_length_prefixed(cbb, &client_shares)) 1234 return 0; 1235 1236 /* XXX - other groups. */ 1237 1238 /* Generate X25519 key pair. */ 1239 if ((public_key = malloc(X25519_KEY_LENGTH)) == NULL) 1240 goto err; 1241 if ((private_key = malloc(X25519_KEY_LENGTH)) == NULL) 1242 goto err; 1243 X25519_keypair(public_key, private_key); 1244 1245 /* Add the group and serialize the public key. */ 1246 if (!CBB_add_u16(&client_shares, tls1_ec_nid2curve_id(NID_X25519))) 1247 goto err; 1248 if (!CBB_add_u16_length_prefixed(&client_shares, &key_exchange)) 1249 goto err; 1250 if (!CBB_add_bytes(&key_exchange, public_key, X25519_KEY_LENGTH)) 1251 goto err; 1252 1253 if (!CBB_flush(cbb)) 1254 goto err; 1255 1256 S3I(s)->hs_tls13.x25519_public = public_key; 1257 S3I(s)->hs_tls13.x25519_private = private_key; 1258 1259 return 1; 1260 1261 err: 1262 freezero(public_key, X25519_KEY_LENGTH); 1263 freezero(private_key, X25519_KEY_LENGTH); 1264 1265 return 0; 1266} 1267 1268int 1269tlsext_keyshare_server_parse(SSL *s, CBS *cbs, int *alert) 1270{ 1271 CBS client_shares; 1272 CBS key_exchange; 1273 uint16_t group; 1274 size_t out_len; 1275 1276 if (!CBS_get_u16_length_prefixed(cbs, &client_shares)) 1277 goto err; 1278 1279 if (CBS_len(cbs) != 0) 1280 goto err; 1281 1282 while (CBS_len(&client_shares) > 0) { 1283 1284 /* Unpack client share. */ 1285 if (!CBS_get_u16(&client_shares, &group)) 1286 goto err; 1287 1288 if (!CBS_get_u16_length_prefixed(&client_shares, &key_exchange)) 1289 goto err; 1290 1291 /* 1292 * Skip this client share if not X25519 1293 * XXX support other groups later. 1294 * XXX enforce group can only appear once. 1295 */ 1296 if (S3I(s)->hs_tls13.x25519_peer_public != NULL || 1297 group != tls1_ec_nid2curve_id(NID_X25519)) 1298 continue; 1299 1300 if (CBS_len(&key_exchange) != X25519_KEY_LENGTH) 1301 goto err; 1302 1303 if (!CBS_stow(&key_exchange, &S3I(s)->hs_tls13.x25519_peer_public, 1304 &out_len)) 1305 goto err; 1306 } 1307 1308 return 1; 1309 1310 err: 1311 *alert = SSL_AD_DECODE_ERROR; 1312 return 0; 1313} 1314 1315int 1316tlsext_keyshare_server_needs(SSL *s) 1317{ 1318 if (SSL_IS_DTLS(s) || s->version < TLS1_3_VERSION) 1319 return 0; 1320 1321 return tlsext_extension_seen(s, TLSEXT_TYPE_key_share); 1322} 1323 1324int 1325tlsext_keyshare_server_build(SSL *s, CBB *cbb) 1326{ 1327 uint8_t *public_key = NULL, *private_key = NULL; 1328 CBB key_exchange; 1329 1330 /* XXX deduplicate with client code */ 1331 1332 /* X25519 */ 1333 if (S3I(s)->hs_tls13.x25519_peer_public == NULL) 1334 return 0; 1335 1336 /* Generate X25519 key pair. */ 1337 if ((public_key = malloc(X25519_KEY_LENGTH)) == NULL) 1338 goto err; 1339 if ((private_key = malloc(X25519_KEY_LENGTH)) == NULL) 1340 goto err; 1341 X25519_keypair(public_key, private_key); 1342 1343 /* Add the group and serialize the public key. */ 1344 if (!CBB_add_u16(cbb, tls1_ec_nid2curve_id(NID_X25519))) 1345 goto err; 1346 if (!CBB_add_u16_length_prefixed(cbb, &key_exchange)) 1347 goto err; 1348 if (!CBB_add_bytes(&key_exchange, public_key, X25519_KEY_LENGTH)) 1349 goto err; 1350 1351 if (!CBB_flush(cbb)) 1352 goto err; 1353 1354 S3I(s)->hs_tls13.x25519_public = public_key; 1355 S3I(s)->hs_tls13.x25519_private = private_key; 1356 1357 return 1; 1358 1359 err: 1360 freezero(public_key, X25519_KEY_LENGTH); 1361 freezero(private_key, X25519_KEY_LENGTH); 1362 1363 return 0; 1364} 1365 1366int 1367tlsext_keyshare_client_parse(SSL *s, CBS *cbs, int *alert) 1368{ 1369 CBS key_exchange; 1370 uint16_t group; 1371 size_t out_len; 1372 1373 /* Unpack server share. */ 1374 if (!CBS_get_u16(cbs, &group)) 1375 goto err; 1376 1377 /* Handle other groups and verify that they're valid. */ 1378 if (group != tls1_ec_nid2curve_id(NID_X25519)) 1379 goto err; 1380 1381 if (!CBS_get_u16_length_prefixed(cbs, &key_exchange)) 1382 goto err; 1383 1384 if (CBS_len(&key_exchange) != X25519_KEY_LENGTH) 1385 goto err; 1386 1387 if (!CBS_stow(&key_exchange, &S3I(s)->hs_tls13.x25519_peer_public, 1388 &out_len)) 1389 goto err; 1390 1391 return 1; 1392 1393 err: 1394 *alert = SSL_AD_DECODE_ERROR; 1395 return 0; 1396} 1397 1398/* 1399 * Supported Versions - RFC 8446 section 4.2.1. 1400 */ 1401int 1402tlsext_versions_client_needs(SSL *s) 1403{ 1404 if (SSL_IS_DTLS(s)) 1405 return 0; 1406 return (S3I(s)->hs_tls13.max_version >= TLS1_3_VERSION); 1407} 1408 1409int 1410tlsext_versions_client_build(SSL *s, CBB *cbb) 1411{ 1412 uint16_t max, min; 1413 uint16_t version; 1414 CBB versions; 1415 1416 max = S3I(s)->hs_tls13.max_version; 1417 min = S3I(s)->hs_tls13.min_version; 1418 1419 if (min < TLS1_VERSION) 1420 return 0; 1421 1422 if (!CBB_add_u8_length_prefixed(cbb, &versions)) 1423 return 0; 1424 1425 /* XXX - fix, but contiguous for now... */ 1426 for (version = max; version >= min; version--) { 1427 if (!CBB_add_u16(&versions, version)) 1428 return 0; 1429 } 1430 1431 if (!CBB_flush(cbb)) 1432 return 0; 1433 1434 return 1; 1435} 1436 1437int 1438tlsext_versions_server_parse(SSL *s, CBS *cbs, int *alert) 1439{ 1440 CBS versions; 1441 uint16_t version; 1442 uint16_t max, min; 1443 uint16_t matched_version = 0; 1444 1445 max = S3I(s)->hs_tls13.max_version; 1446 min = S3I(s)->hs_tls13.min_version; 1447 1448 if (!CBS_get_u8_length_prefixed(cbs, &versions)) 1449 goto err; 1450 1451 while (CBS_len(&versions) > 0) { 1452 if (!CBS_get_u16(&versions, &version)) 1453 goto err; 1454 /* 1455 * XXX What is below implements client preference, and 1456 * ignores any server preference entirely. 1457 */ 1458 if (matched_version == 0 && version >= min && version <= max) 1459 matched_version = version; 1460 } 1461 1462 /* 1463 * XXX if we haven't matched a version we should 1464 * fail - but we currently need to succeed to 1465 * ignore this before the server code for 1.3 1466 * is set up and initialized. 1467 */ 1468 if (max == 0) 1469 return 1; /* XXX */ 1470 1471 if (matched_version != 0) { 1472 s->version = matched_version; 1473 return 1; 1474 } 1475 1476 *alert = SSL_AD_PROTOCOL_VERSION; 1477 return 0; 1478 1479 err: 1480 *alert = SSL_AD_DECODE_ERROR; 1481 return 0; 1482} 1483 1484int 1485tlsext_versions_server_needs(SSL *s) 1486{ 1487 return (!SSL_IS_DTLS(s) && s->version >= TLS1_3_VERSION); 1488} 1489 1490int 1491tlsext_versions_server_build(SSL *s, CBB *cbb) 1492{ 1493 if (!CBB_add_u16(cbb, TLS1_3_VERSION)) 1494 return 0; 1495 /* XXX set 1.2 in legacy version? */ 1496 1497 return 1; 1498} 1499 1500int 1501tlsext_versions_client_parse(SSL *s, CBS *cbs, int *alert) 1502{ 1503 uint16_t selected_version; 1504 1505 if (!CBS_get_u16(cbs, &selected_version)) { 1506 *alert = SSL_AD_DECODE_ERROR; 1507 return 0; 1508 } 1509 1510 if (selected_version < TLS1_3_VERSION) { 1511 *alert = SSL_AD_ILLEGAL_PARAMETER; 1512 return 0; 1513 } 1514 1515 /* XXX test between min and max once initialization code goes in */ 1516 S3I(s)->hs_tls13.server_version = selected_version; 1517 1518 return 1; 1519} 1520 1521 1522/* 1523 * Cookie - RFC 8446 section 4.2.2. 1524 */ 1525 1526int 1527tlsext_cookie_client_needs(SSL *s) 1528{ 1529 if (SSL_IS_DTLS(s)) 1530 return 0; 1531 if (S3I(s)->hs_tls13.max_version < TLS1_3_VERSION) 1532 return 0; 1533 return (S3I(s)->hs_tls13.cookie_len > 0 && 1534 S3I(s)->hs_tls13.cookie != NULL); 1535} 1536 1537int 1538tlsext_cookie_client_build(SSL *s, CBB *cbb) 1539{ 1540 CBB cookie; 1541 1542 if (!CBB_add_u16_length_prefixed(cbb, &cookie)) 1543 return 0; 1544 1545 if (!CBB_add_bytes(&cookie, S3I(s)->hs_tls13.cookie, 1546 S3I(s)->hs_tls13.cookie_len)) 1547 return 0; 1548 1549 if (!CBB_flush(cbb)) 1550 return 0; 1551 1552 return 1; 1553} 1554 1555int 1556tlsext_cookie_server_parse(SSL *s, CBS *cbs, int *alert) 1557{ 1558 CBS cookie; 1559 1560 if (!CBS_get_u16_length_prefixed(cbs, &cookie)) 1561 goto err; 1562 1563 if (CBS_len(&cookie) != S3I(s)->hs_tls13.cookie_len) 1564 goto err; 1565 1566 /* 1567 * Check provided cookie value against what server previously 1568 * sent - client *MUST* send the same cookie with new CR after 1569 * a cookie is sent by the server with an HRR. 1570 */ 1571 if (!CBS_mem_equal(&cookie, S3I(s)->hs_tls13.cookie, 1572 S3I(s)->hs_tls13.cookie_len)) { 1573 /* XXX special cookie mismatch alert? */ 1574 *alert = SSL_AD_ILLEGAL_PARAMETER; 1575 return 0; 1576 } 1577 1578 return 1; 1579 1580 err: 1581 *alert = SSL_AD_DECODE_ERROR; 1582 return 0; 1583} 1584 1585int 1586tlsext_cookie_server_needs(SSL *s) 1587{ 1588 1589 if (SSL_IS_DTLS(s)) 1590 return 0; 1591 if (S3I(s)->hs_tls13.max_version < TLS1_3_VERSION) 1592 return 0; 1593 /* 1594 * Server needs to set cookie value in tls13 handshake 1595 * in order to send one, should only be sent with HRR. 1596 */ 1597 return (S3I(s)->hs_tls13.cookie_len > 0 && 1598 S3I(s)->hs_tls13.cookie != NULL); 1599} 1600 1601int 1602tlsext_cookie_server_build(SSL *s, CBB *cbb) 1603{ 1604 CBB cookie; 1605 1606 /* XXX deduplicate with client code */ 1607 1608 if (!CBB_add_u16_length_prefixed(cbb, &cookie)) 1609 return 0; 1610 1611 if (!CBB_add_bytes(&cookie, S3I(s)->hs_tls13.cookie, 1612 S3I(s)->hs_tls13.cookie_len)) 1613 return 0; 1614 1615 if (!CBB_flush(cbb)) 1616 return 0; 1617 1618 return 1; 1619} 1620 1621int 1622tlsext_cookie_client_parse(SSL *s, CBS *cbs, int *alert) 1623{ 1624 CBS cookie; 1625 1626 /* 1627 * XXX This currently assumes we will not get a second 1628 * HRR from a server with a cookie to process after accepting 1629 * one from the server in the same handshake 1630 */ 1631 if (S3I(s)->hs_tls13.cookie != NULL || 1632 S3I(s)->hs_tls13.cookie_len != 0) { 1633 *alert = SSL_AD_ILLEGAL_PARAMETER; 1634 return 0; 1635 } 1636 1637 if (!CBS_get_u16_length_prefixed(cbs, &cookie)) 1638 goto err; 1639 1640 if (!CBS_stow(&cookie, &S3I(s)->hs_tls13.cookie, 1641 &S3I(s)->hs_tls13.cookie_len)) 1642 goto err; 1643 1644 return 1; 1645 1646 err: 1647 *alert = SSL_AD_DECODE_ERROR; 1648 return 0; 1649} 1650 1651struct tls_extension_funcs { 1652 int (*needs)(SSL *s); 1653 int (*build)(SSL *s, CBB *cbb); 1654 int (*parse)(SSL *s, CBS *cbs, int *alert); 1655}; 1656 1657struct tls_extension { 1658 uint16_t type; 1659 uint16_t messages; 1660 struct tls_extension_funcs client; 1661 struct tls_extension_funcs server; 1662}; 1663 1664static struct tls_extension tls_extensions[] = { 1665 { 1666 .type = TLSEXT_TYPE_supported_versions, 1667 .messages = SSL_TLSEXT_MSG_CH | SSL_TLSEXT_MSG_SH | 1668 SSL_TLSEXT_MSG_HRR, 1669 .client = { 1670 .needs = tlsext_versions_client_needs, 1671 .build = tlsext_versions_client_build, 1672 .parse = tlsext_versions_client_parse, 1673 }, 1674 .server = { 1675 .needs = tlsext_versions_server_needs, 1676 .build = tlsext_versions_server_build, 1677 .parse = tlsext_versions_server_parse, 1678 }, 1679 }, 1680 { 1681 .type = TLSEXT_TYPE_key_share, 1682 .messages = SSL_TLSEXT_MSG_CH | SSL_TLSEXT_MSG_SH | 1683 SSL_TLSEXT_MSG_HRR, 1684 .client = { 1685 .needs = tlsext_keyshare_client_needs, 1686 .build = tlsext_keyshare_client_build, 1687 .parse = tlsext_keyshare_client_parse, 1688 }, 1689 .server = { 1690 .needs = tlsext_keyshare_server_needs, 1691 .build = tlsext_keyshare_server_build, 1692 .parse = tlsext_keyshare_server_parse, 1693 }, 1694 }, 1695 { 1696 .type = TLSEXT_TYPE_server_name, 1697 .messages = SSL_TLSEXT_MSG_CH | SSL_TLSEXT_MSG_EE, 1698 .client = { 1699 .needs = tlsext_sni_client_needs, 1700 .build = tlsext_sni_client_build, 1701 .parse = tlsext_sni_client_parse, 1702 }, 1703 .server = { 1704 .needs = tlsext_sni_server_needs, 1705 .build = tlsext_sni_server_build, 1706 .parse = tlsext_sni_server_parse, 1707 }, 1708 }, 1709 { 1710 .type = TLSEXT_TYPE_renegotiate, 1711 .messages = SSL_TLSEXT_MSG_CH | SSL_TLSEXT_MSG_SH, 1712 .client = { 1713 .needs = tlsext_ri_client_needs, 1714 .build = tlsext_ri_client_build, 1715 .parse = tlsext_ri_client_parse, 1716 }, 1717 .server = { 1718 .needs = tlsext_ri_server_needs, 1719 .build = tlsext_ri_server_build, 1720 .parse = tlsext_ri_server_parse, 1721 }, 1722 }, 1723 { 1724 .type = TLSEXT_TYPE_status_request, 1725 .messages = SSL_TLSEXT_MSG_CH | SSL_TLSEXT_MSG_CR | 1726 SSL_TLSEXT_MSG_CT, 1727 .client = { 1728 .needs = tlsext_ocsp_client_needs, 1729 .build = tlsext_ocsp_client_build, 1730 .parse = tlsext_ocsp_client_parse, 1731 }, 1732 .server = { 1733 .needs = tlsext_ocsp_server_needs, 1734 .build = tlsext_ocsp_server_build, 1735 .parse = tlsext_ocsp_server_parse, 1736 }, 1737 }, 1738 { 1739 .type = TLSEXT_TYPE_ec_point_formats, 1740 .messages = SSL_TLSEXT_MSG_CH | SSL_TLSEXT_MSG_SH, 1741 .client = { 1742 .needs = tlsext_ecpf_client_needs, 1743 .build = tlsext_ecpf_client_build, 1744 .parse = tlsext_ecpf_client_parse, 1745 }, 1746 .server = { 1747 .needs = tlsext_ecpf_server_needs, 1748 .build = tlsext_ecpf_server_build, 1749 .parse = tlsext_ecpf_server_parse, 1750 }, 1751 }, 1752 { 1753 .type = TLSEXT_TYPE_supported_groups, 1754 .messages = SSL_TLSEXT_MSG_CH | SSL_TLSEXT_MSG_EE, 1755 .client = { 1756 .needs = tlsext_supportedgroups_client_needs, 1757 .build = tlsext_supportedgroups_client_build, 1758 .parse = tlsext_supportedgroups_client_parse, 1759 }, 1760 .server = { 1761 .needs = tlsext_supportedgroups_server_needs, 1762 .build = tlsext_supportedgroups_server_build, 1763 .parse = tlsext_supportedgroups_server_parse, 1764 }, 1765 }, 1766 { 1767 .type = TLSEXT_TYPE_session_ticket, 1768 .messages = SSL_TLSEXT_MSG_CH | SSL_TLSEXT_MSG_SH, 1769 .client = { 1770 .needs = tlsext_sessionticket_client_needs, 1771 .build = tlsext_sessionticket_client_build, 1772 .parse = tlsext_sessionticket_client_parse, 1773 }, 1774 .server = { 1775 .needs = tlsext_sessionticket_server_needs, 1776 .build = tlsext_sessionticket_server_build, 1777 .parse = tlsext_sessionticket_server_parse, 1778 }, 1779 }, 1780 { 1781 .type = TLSEXT_TYPE_signature_algorithms, 1782 .messages = SSL_TLSEXT_MSG_CH | SSL_TLSEXT_MSG_CR, 1783 .client = { 1784 .needs = tlsext_sigalgs_client_needs, 1785 .build = tlsext_sigalgs_client_build, 1786 .parse = tlsext_sigalgs_client_parse, 1787 }, 1788 .server = { 1789 .needs = tlsext_sigalgs_server_needs, 1790 .build = tlsext_sigalgs_server_build, 1791 .parse = tlsext_sigalgs_server_parse, 1792 }, 1793 }, 1794 { 1795 .type = TLSEXT_TYPE_application_layer_protocol_negotiation, 1796 .messages = SSL_TLSEXT_MSG_CH | SSL_TLSEXT_MSG_EE, 1797 .client = { 1798 .needs = tlsext_alpn_client_needs, 1799 .build = tlsext_alpn_client_build, 1800 .parse = tlsext_alpn_client_parse, 1801 }, 1802 .server = { 1803 .needs = tlsext_alpn_server_needs, 1804 .build = tlsext_alpn_server_build, 1805 .parse = tlsext_alpn_server_parse, 1806 }, 1807 }, 1808 { 1809 .type = TLSEXT_TYPE_cookie, 1810 .messages = SSL_TLSEXT_MSG_CH | SSL_TLSEXT_MSG_HRR, 1811 .client = { 1812 .needs = tlsext_cookie_client_needs, 1813 .build = tlsext_cookie_client_build, 1814 .parse = tlsext_cookie_client_parse, 1815 }, 1816 .server = { 1817 .needs = tlsext_cookie_server_needs, 1818 .build = tlsext_cookie_server_build, 1819 .parse = tlsext_cookie_server_parse, 1820 }, 1821 }, 1822#ifndef OPENSSL_NO_SRTP 1823 { 1824 .type = TLSEXT_TYPE_use_srtp, 1825 .messages = SSL_TLSEXT_MSG_CH | SSL_TLSEXT_MSG_SH /* XXX */ | 1826 SSL_TLSEXT_MSG_EE, 1827 .client = { 1828 .needs = tlsext_srtp_client_needs, 1829 .build = tlsext_srtp_client_build, 1830 .parse = tlsext_srtp_client_parse, 1831 }, 1832 .server = { 1833 .needs = tlsext_srtp_server_needs, 1834 .build = tlsext_srtp_server_build, 1835 .parse = tlsext_srtp_server_parse, 1836 }, 1837 } 1838#endif /* OPENSSL_NO_SRTP */ 1839}; 1840 1841#define N_TLS_EXTENSIONS (sizeof(tls_extensions) / sizeof(*tls_extensions)) 1842 1843/* Ensure that extensions fit in a uint32_t bitmask. */ 1844CTASSERT(N_TLS_EXTENSIONS <= (sizeof(uint32_t) * 8)); 1845 1846struct tls_extension * 1847tls_extension_find(uint16_t type, size_t *tls_extensions_idx) 1848{ 1849 size_t i; 1850 1851 for (i = 0; i < N_TLS_EXTENSIONS; i++) { 1852 if (tls_extensions[i].type == type) { 1853 *tls_extensions_idx = i; 1854 return &tls_extensions[i]; 1855 } 1856 } 1857 1858 return NULL; 1859} 1860 1861int 1862tlsext_extension_seen(SSL *s, uint16_t type) 1863{ 1864 size_t idx; 1865 1866 if (tls_extension_find(type, &idx) == NULL) 1867 return 0; 1868 return ((S3I(s)->hs.extensions_seen & (1 << idx)) != 0); 1869} 1870 1871static struct tls_extension_funcs * 1872tlsext_funcs(struct tls_extension *tlsext, int is_server) 1873{ 1874 if (is_server) 1875 return &tlsext->server; 1876 1877 return &tlsext->client; 1878} 1879 1880static int 1881tlsext_build(SSL *s, CBB *cbb, int is_server, uint16_t msg_type) 1882{ 1883 struct tls_extension_funcs *ext; 1884 struct tls_extension *tlsext; 1885 CBB extensions, extension_data; 1886 int extensions_present = 0; 1887 size_t i; 1888 uint16_t version; 1889 1890 if (is_server) 1891 version = s->version; 1892 else 1893 version = TLS1_get_client_version(s); 1894 1895 if (!CBB_add_u16_length_prefixed(cbb, &extensions)) 1896 return 0; 1897 1898 for (i = 0; i < N_TLS_EXTENSIONS; i++) { 1899 tlsext = &tls_extensions[i]; 1900 ext = tlsext_funcs(tlsext, is_server); 1901 1902 /* RFC 8446 Section 4.2 */ 1903 if (version >= TLS1_3_VERSION && 1904 !(tlsext->messages & msg_type)) 1905 continue; 1906 1907 if (!ext->needs(s)) 1908 continue; 1909 1910 if (!CBB_add_u16(&extensions, tlsext->type)) 1911 return 0; 1912 if (!CBB_add_u16_length_prefixed(&extensions, &extension_data)) 1913 return 0; 1914 1915 if (!ext->build(s, &extension_data)) 1916 return 0; 1917 1918 extensions_present = 1; 1919 } 1920 1921 if (!extensions_present) 1922 CBB_discard_child(cbb); 1923 1924 if (!CBB_flush(cbb)) 1925 return 0; 1926 1927 return 1; 1928} 1929 1930static int 1931tlsext_parse(SSL *s, CBS *cbs, int *alert, int is_server, uint16_t msg_type) 1932{ 1933 struct tls_extension_funcs *ext; 1934 struct tls_extension *tlsext; 1935 CBS extensions, extension_data; 1936 uint16_t type; 1937 size_t idx; 1938 uint16_t version; 1939 int alert_desc; 1940 1941 S3I(s)->hs.extensions_seen = 0; 1942 1943 if (is_server) 1944 version = s->version; 1945 else 1946 version = TLS1_get_client_version(s); 1947 1948 /* An empty extensions block is valid. */ 1949 if (CBS_len(cbs) == 0) 1950 return 1; 1951 1952 alert_desc = SSL_AD_DECODE_ERROR; 1953 1954 if (!CBS_get_u16_length_prefixed(cbs, &extensions)) 1955 goto err; 1956 1957 while (CBS_len(&extensions) > 0) { 1958 if (!CBS_get_u16(&extensions, &type)) 1959 goto err; 1960 if (!CBS_get_u16_length_prefixed(&extensions, &extension_data)) 1961 goto err; 1962 1963 if (s->internal->tlsext_debug_cb != NULL) 1964 s->internal->tlsext_debug_cb(s, is_server, type, 1965 (unsigned char *)CBS_data(&extension_data), 1966 CBS_len(&extension_data), 1967 s->internal->tlsext_debug_arg); 1968 1969 /* Unknown extensions are ignored. */ 1970 if ((tlsext = tls_extension_find(type, &idx)) == NULL) 1971 continue; 1972 1973 /* RFC 8446 Section 4.2 */ 1974 if (version >= TLS1_3_VERSION && 1975 !(tlsext->messages & msg_type)) { 1976 alert_desc = SSL_AD_ILLEGAL_PARAMETER; 1977 goto err; 1978 } 1979 1980 /* Check for duplicate known extensions. */ 1981 if ((S3I(s)->hs.extensions_seen & (1 << idx)) != 0) 1982 goto err; 1983 S3I(s)->hs.extensions_seen |= (1 << idx); 1984 1985 ext = tlsext_funcs(tlsext, is_server); 1986 if (!ext->parse(s, &extension_data, &alert_desc)) 1987 goto err; 1988 1989 if (CBS_len(&extension_data) != 0) 1990 goto err; 1991 } 1992 1993 return 1; 1994 1995 err: 1996 *alert = alert_desc; 1997 1998 return 0; 1999} 2000 2001static void 2002tlsext_server_reset_state(SSL *s) 2003{ 2004 s->internal->servername_done = 0; 2005 s->tlsext_status_type = -1; 2006 S3I(s)->renegotiate_seen = 0; 2007 free(S3I(s)->alpn_selected); 2008 S3I(s)->alpn_selected = NULL; 2009 s->internal->srtp_profile = NULL; 2010} 2011 2012int 2013tlsext_server_build(SSL *s, CBB *cbb, uint16_t msg_type) 2014{ 2015 return tlsext_build(s, cbb, 1, msg_type); 2016} 2017 2018int 2019tlsext_server_parse(SSL *s, CBS *cbs, int *alert, uint16_t msg_type) 2020{ 2021 /* XXX - this possibly should be done by the caller... */ 2022 tlsext_server_reset_state(s); 2023 2024 return tlsext_parse(s, cbs, alert, 1, msg_type); 2025} 2026 2027static void 2028tlsext_client_reset_state(SSL *s) 2029{ 2030 S3I(s)->renegotiate_seen = 0; 2031 free(S3I(s)->alpn_selected); 2032 S3I(s)->alpn_selected = NULL; 2033} 2034 2035int 2036tlsext_client_build(SSL *s, CBB *cbb, uint16_t msg_type) 2037{ 2038 return tlsext_build(s, cbb, 0, msg_type); 2039} 2040 2041int 2042tlsext_client_parse(SSL *s, CBS *cbs, int *alert, uint16_t msg_type) 2043{ 2044 /* XXX - this possibly should be done by the caller... */ 2045 tlsext_client_reset_state(s); 2046 2047 return tlsext_parse(s, cbs, alert, 0, msg_type); 2048} 2049