1/* 2 * TLS 1.3 server-side functions 3 * 4 * Copyright The Mbed TLS Contributors 5 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later 6 */ 7 8#include "common.h" 9 10#if defined(MBEDTLS_SSL_SRV_C) && defined(MBEDTLS_SSL_PROTO_TLS1_3) 11 12#include "debug_internal.h" 13#include "mbedtls/error.h" 14#include "mbedtls/platform.h" 15#include "mbedtls/constant_time.h" 16#include "mbedtls/oid.h" 17#include "mbedtls/psa_util.h" 18 19#include "ssl_misc.h" 20#include "ssl_tls13_keys.h" 21#include "ssl_debug_helpers.h" 22 23 24static const mbedtls_ssl_ciphersuite_t *ssl_tls13_validate_peer_ciphersuite( 25 mbedtls_ssl_context *ssl, 26 unsigned int cipher_suite) 27{ 28 const mbedtls_ssl_ciphersuite_t *ciphersuite_info; 29 if (!mbedtls_ssl_tls13_cipher_suite_is_offered(ssl, cipher_suite)) { 30 return NULL; 31 } 32 33 ciphersuite_info = mbedtls_ssl_ciphersuite_from_id(cipher_suite); 34 if ((mbedtls_ssl_validate_ciphersuite(ssl, ciphersuite_info, 35 ssl->tls_version, 36 ssl->tls_version) != 0)) { 37 return NULL; 38 } 39 return ciphersuite_info; 40} 41 42static void ssl_tls13_select_ciphersuite( 43 mbedtls_ssl_context *ssl, 44 const unsigned char *cipher_suites, 45 const unsigned char *cipher_suites_end, 46 int psk_ciphersuite_id, 47 psa_algorithm_t psk_hash_alg, 48 const mbedtls_ssl_ciphersuite_t **selected_ciphersuite_info) 49{ 50 *selected_ciphersuite_info = NULL; 51 52 /* 53 * In a compliant ClientHello the byte-length of the list of ciphersuites 54 * is even and this function relies on this fact. This should have been 55 * checked in the main ClientHello parsing function. Double check here. 56 */ 57 if ((cipher_suites_end - cipher_suites) & 1) { 58 return; 59 } 60 61 for (const unsigned char *p = cipher_suites; 62 p < cipher_suites_end; p += 2) { 63 /* 64 * "cipher_suites_end - p is even" is an invariant of the loop. As 65 * cipher_suites_end - p > 0, we have cipher_suites_end - p >= 2 and it 66 * is thus safe to read two bytes. 67 */ 68 uint16_t id = MBEDTLS_GET_UINT16_BE(p, 0); 69 70 const mbedtls_ssl_ciphersuite_t *info = 71 ssl_tls13_validate_peer_ciphersuite(ssl, id); 72 if (info == NULL) { 73 continue; 74 } 75 76 /* 77 * If a valid PSK ciphersuite identifier has been passed in, we want 78 * an exact match. 79 */ 80 if (psk_ciphersuite_id != 0) { 81 if (id != psk_ciphersuite_id) { 82 continue; 83 } 84 } else if (psk_hash_alg != PSA_ALG_NONE) { 85 if (mbedtls_md_psa_alg_from_type((mbedtls_md_type_t) info->mac) != 86 psk_hash_alg) { 87 continue; 88 } 89 } 90 91 *selected_ciphersuite_info = info; 92 return; 93 } 94 95 MBEDTLS_SSL_DEBUG_MSG(2, ("No matched ciphersuite, psk_ciphersuite_id=%x, psk_hash_alg=%x", 96 (unsigned) psk_ciphersuite_id, psk_hash_alg)); 97} 98 99#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) 100/* From RFC 8446: 101 * 102 * enum { psk_ke(0), psk_dhe_ke(1), (255) } PskKeyExchangeMode; 103 * struct { 104 * PskKeyExchangeMode ke_modes<1..255>; 105 * } PskKeyExchangeModes; 106 */ 107MBEDTLS_CHECK_RETURN_CRITICAL 108static int ssl_tls13_parse_key_exchange_modes_ext(mbedtls_ssl_context *ssl, 109 const unsigned char *buf, 110 const unsigned char *end) 111{ 112 const unsigned char *p = buf; 113 size_t ke_modes_len; 114 int ke_modes = 0; 115 116 /* Read ke_modes length (1 Byte) */ 117 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 1); 118 ke_modes_len = *p++; 119 /* Currently, there are only two PSK modes, so even without looking 120 * at the content, something's wrong if the list has more than 2 items. */ 121 if (ke_modes_len > 2) { 122 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER, 123 MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER); 124 return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE; 125 } 126 127 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, ke_modes_len); 128 129 while (ke_modes_len-- != 0) { 130 switch (*p++) { 131 case MBEDTLS_SSL_TLS1_3_PSK_MODE_PURE: 132 ke_modes |= MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK; 133 MBEDTLS_SSL_DEBUG_MSG(3, ("Found PSK KEX MODE")); 134 break; 135 case MBEDTLS_SSL_TLS1_3_PSK_MODE_ECDHE: 136 ke_modes |= MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL; 137 MBEDTLS_SSL_DEBUG_MSG(3, ("Found PSK_EPHEMERAL KEX MODE")); 138 break; 139 default: 140 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER, 141 MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER); 142 return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER; 143 } 144 } 145 146 ssl->handshake->tls13_kex_modes = ke_modes; 147 return 0; 148} 149 150/* 151 * Non-error return values of 152 * ssl_tls13_offered_psks_check_identity_match_ticket() and 153 * ssl_tls13_offered_psks_check_identity_match(). They are positive to 154 * not collide with error codes that are negative. Zero 155 * (SSL_TLS1_3_PSK_IDENTITY_MATCH) in case of success as it may be propagated 156 * up by the callers of this function as a generic success condition. 157 * 158 * The return value SSL_TLS1_3_PSK_IDENTITY_MATCH_BUT_PSK_NOT_USABLE means 159 * that the pre-shared-key identity matches that of a ticket or an externally- 160 * provisioned pre-shared-key. We have thus been able to retrieve the 161 * attributes of the pre-shared-key but at least one of them does not meet 162 * some criteria and the pre-shared-key cannot be used. For example, a ticket 163 * is expired or its version is not TLS 1.3. Note eventually that the return 164 * value SSL_TLS1_3_PSK_IDENTITY_MATCH_BUT_PSK_NOT_USABLE does not have 165 * anything to do with binder check. A binder check is done only when a 166 * suitable pre-shared-key has been selected and only for that selected 167 * pre-shared-key: if the binder check fails, we fail the handshake and we do 168 * not try to find another pre-shared-key for which the binder check would 169 * succeed as recommended by the specification. 170 */ 171#define SSL_TLS1_3_PSK_IDENTITY_DOES_NOT_MATCH 2 172#define SSL_TLS1_3_PSK_IDENTITY_MATCH_BUT_PSK_NOT_USABLE 1 173#define SSL_TLS1_3_PSK_IDENTITY_MATCH 0 174 175#if defined(MBEDTLS_SSL_SESSION_TICKETS) 176MBEDTLS_CHECK_RETURN_CRITICAL 177static int ssl_tls13_key_exchange_is_psk_available(mbedtls_ssl_context *ssl); 178MBEDTLS_CHECK_RETURN_CRITICAL 179static int ssl_tls13_key_exchange_is_psk_ephemeral_available(mbedtls_ssl_context *ssl); 180 181MBEDTLS_CHECK_RETURN_CRITICAL 182static int ssl_tls13_offered_psks_check_identity_match_ticket( 183 mbedtls_ssl_context *ssl, 184 const unsigned char *identity, 185 size_t identity_len, 186 uint32_t obfuscated_ticket_age, 187 mbedtls_ssl_session *session) 188{ 189 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 190 unsigned char *ticket_buffer; 191#if defined(MBEDTLS_HAVE_TIME) 192 mbedtls_ms_time_t now; 193 mbedtls_ms_time_t server_age; 194 uint32_t client_age; 195 mbedtls_ms_time_t age_diff; 196#endif 197 198 ((void) obfuscated_ticket_age); 199 200 MBEDTLS_SSL_DEBUG_MSG(2, ("=> check_identity_match_ticket")); 201 202 /* Ticket parser is not configured, Skip */ 203 if (ssl->conf->f_ticket_parse == NULL || identity_len == 0) { 204 return SSL_TLS1_3_PSK_IDENTITY_DOES_NOT_MATCH; 205 } 206 207 /* We create a copy of the encrypted ticket since the ticket parsing 208 * function is allowed to use its input buffer as an output buffer 209 * (in-place decryption). We do, however, need the original buffer for 210 * computing the PSK binder value. 211 */ 212 ticket_buffer = mbedtls_calloc(1, identity_len); 213 if (ticket_buffer == NULL) { 214 return MBEDTLS_ERR_SSL_ALLOC_FAILED; 215 } 216 memcpy(ticket_buffer, identity, identity_len); 217 218 ret = ssl->conf->f_ticket_parse(ssl->conf->p_ticket, 219 session, 220 ticket_buffer, identity_len); 221 switch (ret) { 222 case 0: 223 ret = SSL_TLS1_3_PSK_IDENTITY_MATCH; 224 break; 225 226 case MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED: 227 MBEDTLS_SSL_DEBUG_MSG(3, ("ticket is expired")); 228 ret = SSL_TLS1_3_PSK_IDENTITY_MATCH_BUT_PSK_NOT_USABLE; 229 break; 230 231 case MBEDTLS_ERR_SSL_INVALID_MAC: 232 MBEDTLS_SSL_DEBUG_MSG(3, ("ticket is not authentic")); 233 ret = SSL_TLS1_3_PSK_IDENTITY_DOES_NOT_MATCH; 234 break; 235 236 default: 237 MBEDTLS_SSL_DEBUG_RET(1, "ticket_parse", ret); 238 ret = SSL_TLS1_3_PSK_IDENTITY_DOES_NOT_MATCH; 239 } 240 241 /* We delete the temporary buffer */ 242 mbedtls_free(ticket_buffer); 243 244 if (ret != SSL_TLS1_3_PSK_IDENTITY_MATCH) { 245 goto exit; 246 } 247 248 /* 249 * The identity matches that of a ticket. Now check that it has suitable 250 * attributes and bet it will not be the case. 251 */ 252 ret = SSL_TLS1_3_PSK_IDENTITY_MATCH_BUT_PSK_NOT_USABLE; 253 254 if (session->tls_version != MBEDTLS_SSL_VERSION_TLS1_3) { 255 MBEDTLS_SSL_DEBUG_MSG(3, ("Ticket TLS version is not 1.3.")); 256 goto exit; 257 } 258 259#if defined(MBEDTLS_HAVE_TIME) 260 now = mbedtls_ms_time(); 261 262 if (now < session->ticket_creation_time) { 263 MBEDTLS_SSL_DEBUG_MSG( 264 3, ("Invalid ticket creation time ( now = %" MBEDTLS_PRINTF_MS_TIME 265 ", creation_time = %" MBEDTLS_PRINTF_MS_TIME " )", 266 now, session->ticket_creation_time)); 267 goto exit; 268 } 269 270 server_age = now - session->ticket_creation_time; 271 272 /* RFC 8446 section 4.6.1 273 * 274 * Servers MUST NOT use any value greater than 604800 seconds (7 days). 275 * 276 * RFC 8446 section 4.2.11.1 277 * 278 * Clients MUST NOT attempt to use tickets which have ages greater than 279 * the "ticket_lifetime" value which was provided with the ticket. 280 * 281 */ 282 if (server_age > MBEDTLS_SSL_TLS1_3_MAX_ALLOWED_TICKET_LIFETIME * 1000) { 283 MBEDTLS_SSL_DEBUG_MSG( 284 3, ("Ticket age exceeds limitation ticket_age = %" MBEDTLS_PRINTF_MS_TIME, 285 server_age)); 286 goto exit; 287 } 288 289 /* RFC 8446 section 4.2.10 290 * 291 * For PSKs provisioned via NewSessionTicket, a server MUST validate that 292 * the ticket age for the selected PSK identity (computed by subtracting 293 * ticket_age_add from PskIdentity.obfuscated_ticket_age modulo 2^32) is 294 * within a small tolerance of the time since the ticket was issued. 295 * 296 * NOTE: The typical accuracy of an RTC crystal is ��100 to ��20 parts per 297 * million (360 to 72 milliseconds per hour). Default tolerance 298 * window is 6s, thus in the worst case clients and servers must 299 * sync up their system time every 6000/360/2~=8 hours. 300 */ 301 client_age = obfuscated_ticket_age - session->ticket_age_add; 302 age_diff = server_age - (mbedtls_ms_time_t) client_age; 303 if (age_diff < -MBEDTLS_SSL_TLS1_3_TICKET_AGE_TOLERANCE || 304 age_diff > MBEDTLS_SSL_TLS1_3_TICKET_AGE_TOLERANCE) { 305 MBEDTLS_SSL_DEBUG_MSG( 306 3, ("Ticket age outside tolerance window ( diff = %" 307 MBEDTLS_PRINTF_MS_TIME ")", 308 age_diff)); 309 goto exit; 310 } 311#endif /* MBEDTLS_HAVE_TIME */ 312 313 /* 314 * All good, we have found a suitable ticket. 315 */ 316 ret = SSL_TLS1_3_PSK_IDENTITY_MATCH; 317 318exit: 319 if (ret != SSL_TLS1_3_PSK_IDENTITY_MATCH) { 320 mbedtls_ssl_session_free(session); 321 } 322 323 MBEDTLS_SSL_DEBUG_MSG(2, ("<= check_identity_match_ticket")); 324 return ret; 325} 326#endif /* MBEDTLS_SSL_SESSION_TICKETS */ 327 328MBEDTLS_CHECK_RETURN_CRITICAL 329static int ssl_tls13_offered_psks_check_identity_match( 330 mbedtls_ssl_context *ssl, 331 const unsigned char *identity, 332 size_t identity_len, 333 uint32_t obfuscated_ticket_age, 334 int *psk_type, 335 mbedtls_ssl_session *session) 336{ 337 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 338 339 ((void) session); 340 ((void) obfuscated_ticket_age); 341 *psk_type = MBEDTLS_SSL_TLS1_3_PSK_EXTERNAL; 342 343 MBEDTLS_SSL_DEBUG_BUF(4, "identity", identity, identity_len); 344 345#if defined(MBEDTLS_SSL_SESSION_TICKETS) 346 ret = ssl_tls13_offered_psks_check_identity_match_ticket( 347 ssl, identity, identity_len, obfuscated_ticket_age, session); 348 if (ret == SSL_TLS1_3_PSK_IDENTITY_MATCH) { 349 *psk_type = MBEDTLS_SSL_TLS1_3_PSK_RESUMPTION; 350 ret = mbedtls_ssl_set_hs_psk(ssl, 351 session->resumption_key, 352 session->resumption_key_len); 353 if (ret != 0) { 354 MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_set_hs_psk", ret); 355 return ret; 356 } 357 358 MBEDTLS_SSL_DEBUG_BUF(4, "Ticket-resumed PSK:", 359 session->resumption_key, 360 session->resumption_key_len); 361 MBEDTLS_SSL_DEBUG_MSG(4, ("ticket: obfuscated_ticket_age: %u", 362 (unsigned) obfuscated_ticket_age)); 363 return SSL_TLS1_3_PSK_IDENTITY_MATCH; 364 } else if (ret == SSL_TLS1_3_PSK_IDENTITY_MATCH_BUT_PSK_NOT_USABLE) { 365 return SSL_TLS1_3_PSK_IDENTITY_MATCH_BUT_PSK_NOT_USABLE; 366 } 367#endif /* MBEDTLS_SSL_SESSION_TICKETS */ 368 369 /* Check identity with external configured function */ 370 if (ssl->conf->f_psk != NULL) { 371 if (ssl->conf->f_psk( 372 ssl->conf->p_psk, ssl, identity, identity_len) == 0) { 373 return SSL_TLS1_3_PSK_IDENTITY_MATCH; 374 } 375 return SSL_TLS1_3_PSK_IDENTITY_DOES_NOT_MATCH; 376 } 377 378 MBEDTLS_SSL_DEBUG_BUF(5, "identity", identity, identity_len); 379 /* Check identity with pre-configured psk */ 380 if (ssl->conf->psk_identity != NULL && 381 identity_len == ssl->conf->psk_identity_len && 382 mbedtls_ct_memcmp(ssl->conf->psk_identity, 383 identity, identity_len) == 0) { 384 ret = mbedtls_ssl_set_hs_psk(ssl, ssl->conf->psk, ssl->conf->psk_len); 385 if (ret != 0) { 386 MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_set_hs_psk", ret); 387 return ret; 388 } 389 return SSL_TLS1_3_PSK_IDENTITY_MATCH; 390 } 391 392 return SSL_TLS1_3_PSK_IDENTITY_DOES_NOT_MATCH; 393} 394 395/* 396 * Non-error return values of ssl_tls13_offered_psks_check_binder_match(). 397 * They are positive to not collide with error codes that are negative. Zero 398 * (SSL_TLS1_3_BINDER_MATCH) in case of success as it may be propagated up 399 * by the callers of this function as a generic success condition. 400 */ 401#define SSL_TLS1_3_BINDER_DOES_NOT_MATCH 1 402#define SSL_TLS1_3_BINDER_MATCH 0 403MBEDTLS_CHECK_RETURN_CRITICAL 404static int ssl_tls13_offered_psks_check_binder_match( 405 mbedtls_ssl_context *ssl, 406 const unsigned char *binder, size_t binder_len, 407 int psk_type, psa_algorithm_t psk_hash_alg) 408{ 409 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 410 411 unsigned char transcript[PSA_HASH_MAX_SIZE]; 412 size_t transcript_len; 413 unsigned char *psk; 414 size_t psk_len; 415 unsigned char server_computed_binder[PSA_HASH_MAX_SIZE]; 416 417 if (binder_len != PSA_HASH_LENGTH(psk_hash_alg)) { 418 return SSL_TLS1_3_BINDER_DOES_NOT_MATCH; 419 } 420 421 /* Get current state of handshake transcript. */ 422 ret = mbedtls_ssl_get_handshake_transcript( 423 ssl, mbedtls_md_type_from_psa_alg(psk_hash_alg), 424 transcript, sizeof(transcript), &transcript_len); 425 if (ret != 0) { 426 return ret; 427 } 428 429 ret = mbedtls_ssl_tls13_export_handshake_psk(ssl, &psk, &psk_len); 430 if (ret != 0) { 431 return ret; 432 } 433 434 ret = mbedtls_ssl_tls13_create_psk_binder(ssl, psk_hash_alg, 435 psk, psk_len, psk_type, 436 transcript, 437 server_computed_binder); 438#if defined(MBEDTLS_USE_PSA_CRYPTO) 439 mbedtls_free((void *) psk); 440#endif 441 if (ret != 0) { 442 MBEDTLS_SSL_DEBUG_MSG(1, ("PSK binder calculation failed.")); 443 return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE; 444 } 445 446 MBEDTLS_SSL_DEBUG_BUF(3, "psk binder ( computed ): ", 447 server_computed_binder, transcript_len); 448 MBEDTLS_SSL_DEBUG_BUF(3, "psk binder ( received ): ", binder, binder_len); 449 450 if (mbedtls_ct_memcmp(server_computed_binder, 451 binder, 452 PSA_HASH_LENGTH(psk_hash_alg)) == 0) { 453 return SSL_TLS1_3_BINDER_MATCH; 454 } 455 456 mbedtls_platform_zeroize(server_computed_binder, 457 sizeof(server_computed_binder)); 458 return SSL_TLS1_3_BINDER_DOES_NOT_MATCH; 459} 460 461#if defined(MBEDTLS_SSL_SESSION_TICKETS) 462MBEDTLS_CHECK_RETURN_CRITICAL 463static int ssl_tls13_session_copy_ticket(mbedtls_ssl_session *dst, 464 const mbedtls_ssl_session *src) 465{ 466 dst->ticket_age_add = src->ticket_age_add; 467 dst->ticket_flags = src->ticket_flags; 468 dst->resumption_key_len = src->resumption_key_len; 469 if (src->resumption_key_len == 0) { 470 return MBEDTLS_ERR_SSL_INTERNAL_ERROR; 471 } 472 memcpy(dst->resumption_key, src->resumption_key, src->resumption_key_len); 473 474#if defined(MBEDTLS_SSL_EARLY_DATA) 475 dst->max_early_data_size = src->max_early_data_size; 476 477#if defined(MBEDTLS_SSL_ALPN) 478 int ret = mbedtls_ssl_session_set_ticket_alpn(dst, src->ticket_alpn); 479 if (ret != 0) { 480 return ret; 481 } 482#endif /* MBEDTLS_SSL_ALPN */ 483#endif /* MBEDTLS_SSL_EARLY_DATA*/ 484 485 return 0; 486} 487#endif /* MBEDTLS_SSL_SESSION_TICKETS */ 488 489struct psk_attributes { 490 int type; 491 int key_exchange_mode; 492 const mbedtls_ssl_ciphersuite_t *ciphersuite_info; 493}; 494#define PSK_ATTRIBUTES_INIT { 0, 0, NULL } 495 496/* Parser for pre_shared_key extension in client hello 497 * struct { 498 * opaque identity<1..2^16-1>; 499 * uint32 obfuscated_ticket_age; 500 * } PskIdentity; 501 * 502 * opaque PskBinderEntry<32..255>; 503 * 504 * struct { 505 * PskIdentity identities<7..2^16-1>; 506 * PskBinderEntry binders<33..2^16-1>; 507 * } OfferedPsks; 508 * 509 * struct { 510 * select (Handshake.msg_type) { 511 * case client_hello: OfferedPsks; 512 * .... 513 * }; 514 * } PreSharedKeyExtension; 515 */ 516MBEDTLS_CHECK_RETURN_CRITICAL 517static int ssl_tls13_parse_pre_shared_key_ext( 518 mbedtls_ssl_context *ssl, 519 const unsigned char *pre_shared_key_ext, 520 const unsigned char *pre_shared_key_ext_end, 521 const unsigned char *ciphersuites, 522 const unsigned char *ciphersuites_end, 523 struct psk_attributes *psk) 524{ 525 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 526 const unsigned char *identities = pre_shared_key_ext; 527 const unsigned char *p_identity_len; 528 size_t identities_len; 529 const unsigned char *identities_end; 530 const unsigned char *binders; 531 const unsigned char *p_binder_len; 532 size_t binders_len; 533 const unsigned char *binders_end; 534 int matched_identity = -1; 535 int identity_id = -1; 536 537 MBEDTLS_SSL_DEBUG_BUF(3, "pre_shared_key extension", 538 pre_shared_key_ext, 539 pre_shared_key_ext_end - pre_shared_key_ext); 540 541 /* identities_len 2 bytes 542 * identities_data >= 7 bytes 543 */ 544 MBEDTLS_SSL_CHK_BUF_READ_PTR(identities, pre_shared_key_ext_end, 7 + 2); 545 identities_len = MBEDTLS_GET_UINT16_BE(identities, 0); 546 p_identity_len = identities + 2; 547 MBEDTLS_SSL_CHK_BUF_READ_PTR(p_identity_len, pre_shared_key_ext_end, 548 identities_len); 549 identities_end = p_identity_len + identities_len; 550 551 /* binders_len 2 bytes 552 * binders >= 33 bytes 553 */ 554 binders = identities_end; 555 MBEDTLS_SSL_CHK_BUF_READ_PTR(binders, pre_shared_key_ext_end, 33 + 2); 556 binders_len = MBEDTLS_GET_UINT16_BE(binders, 0); 557 p_binder_len = binders + 2; 558 MBEDTLS_SSL_CHK_BUF_READ_PTR(p_binder_len, pre_shared_key_ext_end, binders_len); 559 binders_end = p_binder_len + binders_len; 560 561 ret = ssl->handshake->update_checksum(ssl, pre_shared_key_ext, 562 identities_end - pre_shared_key_ext); 563 if (0 != ret) { 564 MBEDTLS_SSL_DEBUG_RET(1, ("update_checksum"), ret); 565 return ret; 566 } 567 568 while (p_identity_len < identities_end && p_binder_len < binders_end) { 569 const unsigned char *identity; 570 size_t identity_len; 571 uint32_t obfuscated_ticket_age; 572 const unsigned char *binder; 573 size_t binder_len; 574 int psk_ciphersuite_id; 575 psa_algorithm_t psk_hash_alg; 576 int allowed_key_exchange_modes; 577 578#if defined(MBEDTLS_SSL_SESSION_TICKETS) 579 mbedtls_ssl_session session; 580 mbedtls_ssl_session_init(&session); 581#endif 582 583 MBEDTLS_SSL_CHK_BUF_READ_PTR(p_identity_len, identities_end, 2 + 1 + 4); 584 identity_len = MBEDTLS_GET_UINT16_BE(p_identity_len, 0); 585 identity = p_identity_len + 2; 586 MBEDTLS_SSL_CHK_BUF_READ_PTR(identity, identities_end, identity_len + 4); 587 obfuscated_ticket_age = MBEDTLS_GET_UINT32_BE(identity, identity_len); 588 p_identity_len += identity_len + 6; 589 590 MBEDTLS_SSL_CHK_BUF_READ_PTR(p_binder_len, binders_end, 1 + 32); 591 binder_len = *p_binder_len; 592 binder = p_binder_len + 1; 593 MBEDTLS_SSL_CHK_BUF_READ_PTR(binder, binders_end, binder_len); 594 p_binder_len += binder_len + 1; 595 596 identity_id++; 597 if (matched_identity != -1) { 598 continue; 599 } 600 601 ret = ssl_tls13_offered_psks_check_identity_match( 602 ssl, identity, identity_len, obfuscated_ticket_age, 603 &psk->type, &session); 604 if (ret != SSL_TLS1_3_PSK_IDENTITY_MATCH) { 605 continue; 606 } 607 608 MBEDTLS_SSL_DEBUG_MSG(4, ("found matched identity")); 609 610 switch (psk->type) { 611 case MBEDTLS_SSL_TLS1_3_PSK_EXTERNAL: 612 psk_ciphersuite_id = 0; 613 psk_hash_alg = PSA_ALG_SHA_256; 614 allowed_key_exchange_modes = 615 MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ALL; 616 break; 617#if defined(MBEDTLS_SSL_SESSION_TICKETS) 618 case MBEDTLS_SSL_TLS1_3_PSK_RESUMPTION: 619 psk_ciphersuite_id = session.ciphersuite; 620 psk_hash_alg = PSA_ALG_NONE; 621 ssl->session_negotiate->ticket_flags = session.ticket_flags; 622 allowed_key_exchange_modes = 623 session.ticket_flags & 624 MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ALL; 625 break; 626#endif 627 default: 628 return MBEDTLS_ERR_SSL_INTERNAL_ERROR; 629 } 630 631 psk->key_exchange_mode = MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_NONE; 632 633 if ((allowed_key_exchange_modes & 634 MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL) && 635 ssl_tls13_key_exchange_is_psk_ephemeral_available(ssl)) { 636 psk->key_exchange_mode = MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL; 637 } else if ((allowed_key_exchange_modes & 638 MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK) && 639 ssl_tls13_key_exchange_is_psk_available(ssl)) { 640 psk->key_exchange_mode = MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK; 641 } 642 643 if (psk->key_exchange_mode == MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_NONE) { 644 MBEDTLS_SSL_DEBUG_MSG(3, ("No suitable PSK key exchange mode")); 645 continue; 646 } 647 648 ssl_tls13_select_ciphersuite(ssl, ciphersuites, ciphersuites_end, 649 psk_ciphersuite_id, psk_hash_alg, 650 &psk->ciphersuite_info); 651 652 if (psk->ciphersuite_info == NULL) { 653#if defined(MBEDTLS_SSL_SESSION_TICKETS) 654 mbedtls_ssl_session_free(&session); 655#endif 656 /* 657 * We consider finding a ciphersuite suitable for the PSK as part 658 * of the validation of its binder. Thus if we do not find one, we 659 * abort the handshake with a decrypt_error alert. 660 */ 661 MBEDTLS_SSL_PEND_FATAL_ALERT( 662 MBEDTLS_SSL_ALERT_MSG_DECRYPT_ERROR, 663 MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE); 664 return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE; 665 } 666 667 ret = ssl_tls13_offered_psks_check_binder_match( 668 ssl, binder, binder_len, psk->type, 669 mbedtls_md_psa_alg_from_type((mbedtls_md_type_t) psk->ciphersuite_info->mac)); 670 if (ret != SSL_TLS1_3_BINDER_MATCH) { 671 /* For security reasons, the handshake should be aborted when we 672 * fail to validate a binder value. See RFC 8446 section 4.2.11.2 673 * and appendix E.6. */ 674#if defined(MBEDTLS_SSL_SESSION_TICKETS) 675 mbedtls_ssl_session_free(&session); 676#endif 677 MBEDTLS_SSL_DEBUG_MSG(3, ("Invalid binder.")); 678 MBEDTLS_SSL_DEBUG_RET( 679 1, "ssl_tls13_offered_psks_check_binder_match", ret); 680 MBEDTLS_SSL_PEND_FATAL_ALERT( 681 MBEDTLS_SSL_ALERT_MSG_DECRYPT_ERROR, 682 MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE); 683 return ret; 684 } 685 686 matched_identity = identity_id; 687 688#if defined(MBEDTLS_SSL_SESSION_TICKETS) 689 if (psk->type == MBEDTLS_SSL_TLS1_3_PSK_RESUMPTION) { 690 ret = ssl_tls13_session_copy_ticket(ssl->session_negotiate, 691 &session); 692 mbedtls_ssl_session_free(&session); 693 if (ret != 0) { 694 return ret; 695 } 696 } 697#endif /* MBEDTLS_SSL_SESSION_TICKETS */ 698 } 699 700 if (p_identity_len != identities_end || p_binder_len != binders_end) { 701 MBEDTLS_SSL_DEBUG_MSG(3, ("pre_shared_key extension decode error")); 702 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR, 703 MBEDTLS_ERR_SSL_DECODE_ERROR); 704 return MBEDTLS_ERR_SSL_DECODE_ERROR; 705 } 706 707 /* Update the handshake transcript with the binder list. */ 708 ret = ssl->handshake->update_checksum( 709 ssl, identities_end, (size_t) (binders_end - identities_end)); 710 if (0 != ret) { 711 MBEDTLS_SSL_DEBUG_RET(1, ("update_checksum"), ret); 712 return ret; 713 } 714 if (matched_identity == -1) { 715 MBEDTLS_SSL_DEBUG_MSG(3, ("No usable PSK or ticket.")); 716 return MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY; 717 } 718 719 ssl->handshake->selected_identity = (uint16_t) matched_identity; 720 MBEDTLS_SSL_DEBUG_MSG(3, ("Pre shared key found")); 721 722 return 0; 723} 724 725/* 726 * struct { 727 * select ( Handshake.msg_type ) { 728 * .... 729 * case server_hello: 730 * uint16 selected_identity; 731 * } 732 * } PreSharedKeyExtension; 733 */ 734static int ssl_tls13_write_server_pre_shared_key_ext(mbedtls_ssl_context *ssl, 735 unsigned char *buf, 736 unsigned char *end, 737 size_t *olen) 738{ 739 unsigned char *p = (unsigned char *) buf; 740 741 *olen = 0; 742 743 int not_using_psk = 0; 744#if defined(MBEDTLS_USE_PSA_CRYPTO) 745 not_using_psk = (mbedtls_svc_key_id_is_null(ssl->handshake->psk_opaque)); 746#else 747 not_using_psk = (ssl->handshake->psk == NULL); 748#endif 749 if (not_using_psk) { 750 /* We shouldn't have called this extension writer unless we've 751 * chosen to use a PSK. */ 752 return MBEDTLS_ERR_SSL_INTERNAL_ERROR; 753 } 754 755 MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, adding pre_shared_key extension")); 756 MBEDTLS_SSL_CHK_BUF_PTR(p, end, 6); 757 758 MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_PRE_SHARED_KEY, p, 0); 759 MBEDTLS_PUT_UINT16_BE(2, p, 2); 760 761 MBEDTLS_PUT_UINT16_BE(ssl->handshake->selected_identity, p, 4); 762 763 *olen = 6; 764 765 MBEDTLS_SSL_DEBUG_MSG(4, ("sent selected_identity: %u", 766 ssl->handshake->selected_identity)); 767 768 mbedtls_ssl_tls13_set_hs_sent_ext_mask(ssl, MBEDTLS_TLS_EXT_PRE_SHARED_KEY); 769 770 return 0; 771} 772 773#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED */ 774 775/* From RFC 8446: 776 * struct { 777 * ProtocolVersion versions<2..254>; 778 * } SupportedVersions; 779 */ 780MBEDTLS_CHECK_RETURN_CRITICAL 781static int ssl_tls13_parse_supported_versions_ext(mbedtls_ssl_context *ssl, 782 const unsigned char *buf, 783 const unsigned char *end) 784{ 785 const unsigned char *p = buf; 786 size_t versions_len; 787 const unsigned char *versions_end; 788 uint16_t tls_version; 789 int found_supported_version = 0; 790 791 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 1); 792 versions_len = p[0]; 793 p += 1; 794 795 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, versions_len); 796 versions_end = p + versions_len; 797 while (p < versions_end) { 798 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, versions_end, 2); 799 tls_version = mbedtls_ssl_read_version(p, ssl->conf->transport); 800 p += 2; 801 802 if (MBEDTLS_SSL_VERSION_TLS1_3 == tls_version) { 803 found_supported_version = 1; 804 break; 805 } 806 807 if ((MBEDTLS_SSL_VERSION_TLS1_2 == tls_version) && 808 mbedtls_ssl_conf_is_tls12_enabled(ssl->conf)) { 809 found_supported_version = 1; 810 break; 811 } 812 } 813 814 if (!found_supported_version) { 815 MBEDTLS_SSL_DEBUG_MSG(1, ("No supported version found.")); 816 817 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION, 818 MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION); 819 return MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION; 820 } 821 822 MBEDTLS_SSL_DEBUG_MSG(1, ("Negotiated version: [%04x]", 823 (unsigned int) tls_version)); 824 825 return (int) tls_version; 826} 827 828#if defined(PSA_WANT_ALG_ECDH) || defined(PSA_WANT_ALG_FFDH) 829/* 830 * 831 * From RFC 8446: 832 * enum { 833 * ... (0xFFFF) 834 * } NamedGroup; 835 * struct { 836 * NamedGroup named_group_list<2..2^16-1>; 837 * } NamedGroupList; 838 */ 839MBEDTLS_CHECK_RETURN_CRITICAL 840static int ssl_tls13_parse_supported_groups_ext(mbedtls_ssl_context *ssl, 841 const unsigned char *buf, 842 const unsigned char *end) 843{ 844 const unsigned char *p = buf; 845 size_t named_group_list_len; 846 const unsigned char *named_group_list_end; 847 848 MBEDTLS_SSL_DEBUG_BUF(3, "supported_groups extension", p, end - buf); 849 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 2); 850 named_group_list_len = MBEDTLS_GET_UINT16_BE(p, 0); 851 p += 2; 852 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, named_group_list_len); 853 named_group_list_end = p + named_group_list_len; 854 ssl->handshake->hrr_selected_group = 0; 855 856 while (p < named_group_list_end) { 857 uint16_t named_group; 858 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, named_group_list_end, 2); 859 named_group = MBEDTLS_GET_UINT16_BE(p, 0); 860 p += 2; 861 862 MBEDTLS_SSL_DEBUG_MSG(2, 863 ("got named group: %s(%04x)", 864 mbedtls_ssl_named_group_to_str(named_group), 865 named_group)); 866 867 if (!mbedtls_ssl_named_group_is_offered(ssl, named_group) || 868 !mbedtls_ssl_named_group_is_supported(named_group) || 869 ssl->handshake->hrr_selected_group != 0) { 870 continue; 871 } 872 873 MBEDTLS_SSL_DEBUG_MSG(2, 874 ("add named group %s(%04x) into received list.", 875 mbedtls_ssl_named_group_to_str(named_group), 876 named_group)); 877 878 ssl->handshake->hrr_selected_group = named_group; 879 } 880 881 return 0; 882 883} 884#endif /* PSA_WANT_ALG_ECDH || PSA_WANT_ALG_FFDH */ 885 886#define SSL_TLS1_3_PARSE_KEY_SHARES_EXT_NO_MATCH 1 887 888#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED) 889/* 890 * ssl_tls13_parse_key_shares_ext() verifies whether the information in the 891 * extension is correct and stores the first acceptable key share and its 892 * associated group. 893 * 894 * Possible return values are: 895 * - 0: Successful processing of the client provided key share extension. 896 * - SSL_TLS1_3_PARSE_KEY_SHARES_EXT_NO_MATCH: The key shares provided by 897 * the client does not match a group supported by the server. A 898 * HelloRetryRequest will be needed. 899 * - A negative value for fatal errors. 900 */ 901MBEDTLS_CHECK_RETURN_CRITICAL 902static int ssl_tls13_parse_key_shares_ext(mbedtls_ssl_context *ssl, 903 const unsigned char *buf, 904 const unsigned char *end) 905{ 906 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 907 unsigned char const *p = buf; 908 unsigned char const *client_shares_end; 909 size_t client_shares_len; 910 911 /* From RFC 8446: 912 * 913 * struct { 914 * KeyShareEntry client_shares<0..2^16-1>; 915 * } KeyShareClientHello; 916 * 917 */ 918 919 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 2); 920 client_shares_len = MBEDTLS_GET_UINT16_BE(p, 0); 921 p += 2; 922 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, client_shares_len); 923 924 ssl->handshake->offered_group_id = 0; 925 client_shares_end = p + client_shares_len; 926 927 /* We try to find a suitable key share entry and copy it to the 928 * handshake context. Later, we have to find out whether we can do 929 * something with the provided key share or whether we have to 930 * dismiss it and send a HelloRetryRequest message. 931 */ 932 933 while (p < client_shares_end) { 934 uint16_t group; 935 size_t key_exchange_len; 936 const unsigned char *key_exchange; 937 938 /* 939 * struct { 940 * NamedGroup group; 941 * opaque key_exchange<1..2^16-1>; 942 * } KeyShareEntry; 943 */ 944 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, client_shares_end, 4); 945 group = MBEDTLS_GET_UINT16_BE(p, 0); 946 key_exchange_len = MBEDTLS_GET_UINT16_BE(p, 2); 947 p += 4; 948 key_exchange = p; 949 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, client_shares_end, key_exchange_len); 950 p += key_exchange_len; 951 952 /* Continue parsing even if we have already found a match, 953 * for input validation purposes. 954 */ 955 if (!mbedtls_ssl_named_group_is_offered(ssl, group) || 956 !mbedtls_ssl_named_group_is_supported(group) || 957 ssl->handshake->offered_group_id != 0) { 958 continue; 959 } 960 961 /* 962 * ECDHE and FFDHE groups are supported 963 */ 964 if (mbedtls_ssl_tls13_named_group_is_ecdhe(group) || 965 mbedtls_ssl_tls13_named_group_is_ffdh(group)) { 966 MBEDTLS_SSL_DEBUG_MSG(2, ("ECDH/FFDH group: %s (%04x)", 967 mbedtls_ssl_named_group_to_str(group), 968 group)); 969 ret = mbedtls_ssl_tls13_read_public_xxdhe_share( 970 ssl, key_exchange - 2, key_exchange_len + 2); 971 if (ret != 0) { 972 return ret; 973 } 974 975 } else { 976 MBEDTLS_SSL_DEBUG_MSG(4, ("Unrecognized NamedGroup %u", 977 (unsigned) group)); 978 continue; 979 } 980 981 ssl->handshake->offered_group_id = group; 982 } 983 984 985 if (ssl->handshake->offered_group_id == 0) { 986 MBEDTLS_SSL_DEBUG_MSG(1, ("no matching key share")); 987 return SSL_TLS1_3_PARSE_KEY_SHARES_EXT_NO_MATCH; 988 } 989 return 0; 990} 991#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED */ 992 993MBEDTLS_CHECK_RETURN_CRITICAL 994static int ssl_tls13_client_hello_has_exts(mbedtls_ssl_context *ssl, 995 int exts_mask) 996{ 997 int masked = ssl->handshake->received_extensions & exts_mask; 998 return masked == exts_mask; 999} 1000 1001#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED) 1002MBEDTLS_CHECK_RETURN_CRITICAL 1003static int ssl_tls13_client_hello_has_exts_for_ephemeral_key_exchange( 1004 mbedtls_ssl_context *ssl) 1005{ 1006 return ssl_tls13_client_hello_has_exts( 1007 ssl, 1008 MBEDTLS_SSL_EXT_MASK(SUPPORTED_GROUPS) | 1009 MBEDTLS_SSL_EXT_MASK(KEY_SHARE) | 1010 MBEDTLS_SSL_EXT_MASK(SIG_ALG)); 1011} 1012#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */ 1013 1014#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ENABLED) 1015MBEDTLS_CHECK_RETURN_CRITICAL 1016static int ssl_tls13_client_hello_has_exts_for_psk_key_exchange( 1017 mbedtls_ssl_context *ssl) 1018{ 1019 return ssl_tls13_client_hello_has_exts( 1020 ssl, 1021 MBEDTLS_SSL_EXT_MASK(PRE_SHARED_KEY) | 1022 MBEDTLS_SSL_EXT_MASK(PSK_KEY_EXCHANGE_MODES)); 1023} 1024#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ENABLED */ 1025 1026#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL_ENABLED) 1027MBEDTLS_CHECK_RETURN_CRITICAL 1028static int ssl_tls13_client_hello_has_exts_for_psk_ephemeral_key_exchange( 1029 mbedtls_ssl_context *ssl) 1030{ 1031 return ssl_tls13_client_hello_has_exts( 1032 ssl, 1033 MBEDTLS_SSL_EXT_MASK(SUPPORTED_GROUPS) | 1034 MBEDTLS_SSL_EXT_MASK(KEY_SHARE) | 1035 MBEDTLS_SSL_EXT_MASK(PRE_SHARED_KEY) | 1036 MBEDTLS_SSL_EXT_MASK(PSK_KEY_EXCHANGE_MODES)); 1037} 1038#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL_ENABLED */ 1039 1040#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) 1041MBEDTLS_CHECK_RETURN_CRITICAL 1042static int ssl_tls13_key_exchange_is_psk_available(mbedtls_ssl_context *ssl) 1043{ 1044#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ENABLED) 1045 return mbedtls_ssl_conf_tls13_is_psk_enabled(ssl) && 1046 mbedtls_ssl_tls13_is_psk_supported(ssl) && 1047 ssl_tls13_client_hello_has_exts_for_psk_key_exchange(ssl); 1048#else 1049 ((void) ssl); 1050 return 0; 1051#endif 1052} 1053 1054MBEDTLS_CHECK_RETURN_CRITICAL 1055static int ssl_tls13_key_exchange_is_psk_ephemeral_available(mbedtls_ssl_context *ssl) 1056{ 1057#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL_ENABLED) 1058 return mbedtls_ssl_conf_tls13_is_psk_ephemeral_enabled(ssl) && 1059 mbedtls_ssl_tls13_is_psk_ephemeral_supported(ssl) && 1060 ssl_tls13_client_hello_has_exts_for_psk_ephemeral_key_exchange(ssl); 1061#else 1062 ((void) ssl); 1063 return 0; 1064#endif 1065} 1066#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED */ 1067 1068MBEDTLS_CHECK_RETURN_CRITICAL 1069static int ssl_tls13_key_exchange_is_ephemeral_available(mbedtls_ssl_context *ssl) 1070{ 1071#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED) 1072 return mbedtls_ssl_conf_tls13_is_ephemeral_enabled(ssl) && 1073 ssl_tls13_client_hello_has_exts_for_ephemeral_key_exchange(ssl); 1074#else 1075 ((void) ssl); 1076 return 0; 1077#endif 1078} 1079 1080#if defined(MBEDTLS_X509_CRT_PARSE_C) && \ 1081 defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED) 1082 1083#if defined(MBEDTLS_USE_PSA_CRYPTO) 1084static psa_algorithm_t ssl_tls13_iana_sig_alg_to_psa_alg(uint16_t sig_alg) 1085{ 1086 switch (sig_alg) { 1087 case MBEDTLS_TLS1_3_SIG_ECDSA_SECP256R1_SHA256: 1088 return PSA_ALG_ECDSA(PSA_ALG_SHA_256); 1089 case MBEDTLS_TLS1_3_SIG_ECDSA_SECP384R1_SHA384: 1090 return PSA_ALG_ECDSA(PSA_ALG_SHA_384); 1091 case MBEDTLS_TLS1_3_SIG_ECDSA_SECP521R1_SHA512: 1092 return PSA_ALG_ECDSA(PSA_ALG_SHA_512); 1093 case MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA256: 1094 return PSA_ALG_RSA_PSS(PSA_ALG_SHA_256); 1095 case MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA384: 1096 return PSA_ALG_RSA_PSS(PSA_ALG_SHA_384); 1097 case MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA512: 1098 return PSA_ALG_RSA_PSS(PSA_ALG_SHA_512); 1099 case MBEDTLS_TLS1_3_SIG_RSA_PKCS1_SHA256: 1100 return PSA_ALG_RSA_PKCS1V15_SIGN(PSA_ALG_SHA_256); 1101 case MBEDTLS_TLS1_3_SIG_RSA_PKCS1_SHA384: 1102 return PSA_ALG_RSA_PKCS1V15_SIGN(PSA_ALG_SHA_384); 1103 case MBEDTLS_TLS1_3_SIG_RSA_PKCS1_SHA512: 1104 return PSA_ALG_RSA_PKCS1V15_SIGN(PSA_ALG_SHA_512); 1105 default: 1106 return PSA_ALG_NONE; 1107 } 1108} 1109#endif /* MBEDTLS_USE_PSA_CRYPTO */ 1110 1111/* 1112 * Pick best ( private key, certificate chain ) pair based on the signature 1113 * algorithms supported by the client. 1114 */ 1115MBEDTLS_CHECK_RETURN_CRITICAL 1116static int ssl_tls13_pick_key_cert(mbedtls_ssl_context *ssl) 1117{ 1118 mbedtls_ssl_key_cert *key_cert, *key_cert_list; 1119 const uint16_t *sig_alg = ssl->handshake->received_sig_algs; 1120 1121#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) 1122 if (ssl->handshake->sni_key_cert != NULL) { 1123 key_cert_list = ssl->handshake->sni_key_cert; 1124 } else 1125#endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */ 1126 key_cert_list = ssl->conf->key_cert; 1127 1128 if (key_cert_list == NULL) { 1129 MBEDTLS_SSL_DEBUG_MSG(3, ("server has no certificate")); 1130 return -1; 1131 } 1132 1133 for (; *sig_alg != MBEDTLS_TLS1_3_SIG_NONE; sig_alg++) { 1134 if (!mbedtls_ssl_sig_alg_is_offered(ssl, *sig_alg)) { 1135 continue; 1136 } 1137 1138 if (!mbedtls_ssl_tls13_sig_alg_for_cert_verify_is_supported(*sig_alg)) { 1139 continue; 1140 } 1141 1142 for (key_cert = key_cert_list; key_cert != NULL; 1143 key_cert = key_cert->next) { 1144#if defined(MBEDTLS_USE_PSA_CRYPTO) 1145 psa_algorithm_t psa_alg = PSA_ALG_NONE; 1146#endif /* MBEDTLS_USE_PSA_CRYPTO */ 1147 1148 MBEDTLS_SSL_DEBUG_CRT(3, "certificate (chain) candidate", 1149 key_cert->cert); 1150 1151 /* 1152 * This avoids sending the client a cert it'll reject based on 1153 * keyUsage or other extensions. 1154 */ 1155 if (mbedtls_x509_crt_check_key_usage( 1156 key_cert->cert, MBEDTLS_X509_KU_DIGITAL_SIGNATURE) != 0 || 1157 mbedtls_x509_crt_check_extended_key_usage( 1158 key_cert->cert, MBEDTLS_OID_SERVER_AUTH, 1159 MBEDTLS_OID_SIZE(MBEDTLS_OID_SERVER_AUTH)) != 0) { 1160 MBEDTLS_SSL_DEBUG_MSG(3, ("certificate mismatch: " 1161 "(extended) key usage extension")); 1162 continue; 1163 } 1164 1165 MBEDTLS_SSL_DEBUG_MSG(3, 1166 ("ssl_tls13_pick_key_cert:" 1167 "check signature algorithm %s [%04x]", 1168 mbedtls_ssl_sig_alg_to_str(*sig_alg), 1169 *sig_alg)); 1170#if defined(MBEDTLS_USE_PSA_CRYPTO) 1171 psa_alg = ssl_tls13_iana_sig_alg_to_psa_alg(*sig_alg); 1172#endif /* MBEDTLS_USE_PSA_CRYPTO */ 1173 1174 if (mbedtls_ssl_tls13_check_sig_alg_cert_key_match( 1175 *sig_alg, &key_cert->cert->pk) 1176#if defined(MBEDTLS_USE_PSA_CRYPTO) 1177 && psa_alg != PSA_ALG_NONE && 1178 mbedtls_pk_can_do_ext(&key_cert->cert->pk, psa_alg, 1179 PSA_KEY_USAGE_SIGN_HASH) == 1 1180#endif /* MBEDTLS_USE_PSA_CRYPTO */ 1181 ) { 1182 ssl->handshake->key_cert = key_cert; 1183 MBEDTLS_SSL_DEBUG_MSG(3, 1184 ("ssl_tls13_pick_key_cert:" 1185 "selected signature algorithm" 1186 " %s [%04x]", 1187 mbedtls_ssl_sig_alg_to_str(*sig_alg), 1188 *sig_alg)); 1189 MBEDTLS_SSL_DEBUG_CRT( 1190 3, "selected certificate (chain)", 1191 ssl->handshake->key_cert->cert); 1192 return 0; 1193 } 1194 } 1195 } 1196 1197 MBEDTLS_SSL_DEBUG_MSG(2, ("ssl_tls13_pick_key_cert:" 1198 "no suitable certificate found")); 1199 return -1; 1200} 1201#endif /* MBEDTLS_X509_CRT_PARSE_C && 1202 MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */ 1203 1204/* 1205 * 1206 * STATE HANDLING: ClientHello 1207 * 1208 * There are three possible classes of outcomes when parsing the ClientHello: 1209 * 1210 * 1) The ClientHello was well-formed and matched the server's configuration. 1211 * 1212 * In this case, the server progresses to sending its ServerHello. 1213 * 1214 * 2) The ClientHello was well-formed but didn't match the server's 1215 * configuration. 1216 * 1217 * For example, the client might not have offered a key share which 1218 * the server supports, or the server might require a cookie. 1219 * 1220 * In this case, the server sends a HelloRetryRequest. 1221 * 1222 * 3) The ClientHello was ill-formed 1223 * 1224 * In this case, we abort the handshake. 1225 * 1226 */ 1227 1228/* 1229 * Structure of this message: 1230 * 1231 * uint16 ProtocolVersion; 1232 * opaque Random[32]; 1233 * uint8 CipherSuite[2]; // Cryptographic suite selector 1234 * 1235 * struct { 1236 * ProtocolVersion legacy_version = 0x0303; // TLS v1.2 1237 * Random random; 1238 * opaque legacy_session_id<0..32>; 1239 * CipherSuite cipher_suites<2..2^16-2>; 1240 * opaque legacy_compression_methods<1..2^8-1>; 1241 * Extension extensions<8..2^16-1>; 1242 * } ClientHello; 1243 */ 1244 1245#define SSL_CLIENT_HELLO_OK 0 1246#define SSL_CLIENT_HELLO_HRR_REQUIRED 1 1247#define SSL_CLIENT_HELLO_TLS1_2 2 1248 1249MBEDTLS_CHECK_RETURN_CRITICAL 1250static int ssl_tls13_parse_client_hello(mbedtls_ssl_context *ssl, 1251 const unsigned char *buf, 1252 const unsigned char *end) 1253{ 1254 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 1255 const unsigned char *p = buf; 1256 const unsigned char *random; 1257 size_t legacy_session_id_len; 1258 const unsigned char *legacy_session_id; 1259 size_t cipher_suites_len; 1260 const unsigned char *cipher_suites; 1261 const unsigned char *cipher_suites_end; 1262 size_t extensions_len; 1263 const unsigned char *extensions_end; 1264 const unsigned char *supported_versions_data; 1265 const unsigned char *supported_versions_data_end; 1266 mbedtls_ssl_handshake_params *handshake = ssl->handshake; 1267 int hrr_required = 0; 1268 int no_usable_share_for_key_agreement = 0; 1269 1270#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) 1271 int got_psk = 0; 1272 struct psk_attributes psk = PSK_ATTRIBUTES_INIT; 1273 const unsigned char *pre_shared_key_ext = NULL; 1274 const unsigned char *pre_shared_key_ext_end = NULL; 1275#endif 1276 1277 /* 1278 * ClientHello layout: 1279 * 0 . 1 protocol version 1280 * 2 . 33 random bytes 1281 * 34 . 34 session id length ( 1 byte ) 1282 * 35 . 34+x session id 1283 * .. . .. ciphersuite list length ( 2 bytes ) 1284 * .. . .. ciphersuite list 1285 * .. . .. compression alg. list length ( 1 byte ) 1286 * .. . .. compression alg. list 1287 * .. . .. extensions length ( 2 bytes, optional ) 1288 * .. . .. extensions ( optional ) 1289 */ 1290 1291 /* 1292 * Minimal length ( with everything empty and extensions omitted ) is 1293 * 2 + 32 + 1 + 2 + 1 = 38 bytes. Check that first, so that we can 1294 * read at least up to session id length without worrying. 1295 */ 1296 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 38); 1297 1298 /* ... 1299 * ProtocolVersion legacy_version = 0x0303; // TLS 1.2 1300 * ... 1301 * with ProtocolVersion defined as: 1302 * uint16 ProtocolVersion; 1303 */ 1304 if (mbedtls_ssl_read_version(p, ssl->conf->transport) != 1305 MBEDTLS_SSL_VERSION_TLS1_2) { 1306 MBEDTLS_SSL_DEBUG_MSG(1, ("Unsupported version of TLS.")); 1307 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION, 1308 MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION); 1309 return MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION; 1310 } 1311 p += 2; 1312 1313 /* ... 1314 * Random random; 1315 * ... 1316 * with Random defined as: 1317 * opaque Random[32]; 1318 */ 1319 random = p; 1320 p += MBEDTLS_CLIENT_HELLO_RANDOM_LEN; 1321 1322 /* ... 1323 * opaque legacy_session_id<0..32>; 1324 * ... 1325 */ 1326 legacy_session_id_len = *(p++); 1327 legacy_session_id = p; 1328 1329 /* 1330 * Check we have enough data for the legacy session identifier 1331 * and the ciphersuite list length. 1332 */ 1333 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, legacy_session_id_len + 2); 1334 p += legacy_session_id_len; 1335 1336 /* ... 1337 * CipherSuite cipher_suites<2..2^16-2>; 1338 * ... 1339 * with CipherSuite defined as: 1340 * uint8 CipherSuite[2]; 1341 */ 1342 cipher_suites_len = MBEDTLS_GET_UINT16_BE(p, 0); 1343 p += 2; 1344 cipher_suites = p; 1345 1346 /* 1347 * The length of the ciphersuite list has to be even. 1348 */ 1349 if (cipher_suites_len & 1) { 1350 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR, 1351 MBEDTLS_ERR_SSL_DECODE_ERROR); 1352 return MBEDTLS_ERR_SSL_DECODE_ERROR; 1353 } 1354 1355 /* Check we have enough data for the ciphersuite list, the legacy 1356 * compression methods and the length of the extensions. 1357 * 1358 * cipher_suites cipher_suites_len bytes 1359 * legacy_compression_methods 2 bytes 1360 * extensions_len 2 bytes 1361 */ 1362 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, cipher_suites_len + 2 + 2); 1363 p += cipher_suites_len; 1364 cipher_suites_end = p; 1365 1366 /* 1367 * Search for the supported versions extension and parse it to determine 1368 * if the client supports TLS 1.3. 1369 */ 1370 ret = mbedtls_ssl_tls13_is_supported_versions_ext_present_in_exts( 1371 ssl, p + 2, end, 1372 &supported_versions_data, &supported_versions_data_end); 1373 if (ret < 0) { 1374 MBEDTLS_SSL_DEBUG_RET(1, 1375 ("mbedtls_ssl_tls13_is_supported_versions_ext_present_in_exts"), ret); 1376 return ret; 1377 } 1378 1379 if (ret == 0) { 1380 return SSL_CLIENT_HELLO_TLS1_2; 1381 } 1382 1383 if (ret == 1) { 1384 ret = ssl_tls13_parse_supported_versions_ext(ssl, 1385 supported_versions_data, 1386 supported_versions_data_end); 1387 if (ret < 0) { 1388 MBEDTLS_SSL_DEBUG_RET(1, 1389 ("ssl_tls13_parse_supported_versions_ext"), ret); 1390 return ret; 1391 } 1392 1393 /* 1394 * The supported versions extension was parsed successfully as the 1395 * value returned by ssl_tls13_parse_supported_versions_ext() is 1396 * positive. The return value is then equal to 1397 * MBEDTLS_SSL_VERSION_TLS1_2 or MBEDTLS_SSL_VERSION_TLS1_3, defining 1398 * the TLS version to negotiate. 1399 */ 1400 if (MBEDTLS_SSL_VERSION_TLS1_2 == ret) { 1401 return SSL_CLIENT_HELLO_TLS1_2; 1402 } 1403 } 1404 1405 /* 1406 * We negotiate TLS 1.3. 1407 */ 1408 ssl->tls_version = MBEDTLS_SSL_VERSION_TLS1_3; 1409 ssl->session_negotiate->tls_version = MBEDTLS_SSL_VERSION_TLS1_3; 1410 ssl->session_negotiate->endpoint = ssl->conf->endpoint; 1411 1412 /* 1413 * We are negotiating the version 1.3 of the protocol. Do what we have 1414 * postponed: copy of the client random bytes, copy of the legacy session 1415 * identifier and selection of the TLS 1.3 cipher suite. 1416 */ 1417 MBEDTLS_SSL_DEBUG_BUF(3, "client hello, random bytes", 1418 random, MBEDTLS_CLIENT_HELLO_RANDOM_LEN); 1419 memcpy(&handshake->randbytes[0], random, MBEDTLS_CLIENT_HELLO_RANDOM_LEN); 1420 1421 if (legacy_session_id_len > sizeof(ssl->session_negotiate->id)) { 1422 MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); 1423 return MBEDTLS_ERR_SSL_DECODE_ERROR; 1424 } 1425 ssl->session_negotiate->id_len = legacy_session_id_len; 1426 MBEDTLS_SSL_DEBUG_BUF(3, "client hello, session id", 1427 legacy_session_id, legacy_session_id_len); 1428 memcpy(&ssl->session_negotiate->id[0], 1429 legacy_session_id, legacy_session_id_len); 1430 1431 /* 1432 * Search for a matching ciphersuite 1433 */ 1434 MBEDTLS_SSL_DEBUG_BUF(3, "client hello, list of cipher suites", 1435 cipher_suites, cipher_suites_len); 1436 1437 ssl_tls13_select_ciphersuite(ssl, cipher_suites, cipher_suites_end, 1438 0, PSA_ALG_NONE, &handshake->ciphersuite_info); 1439 1440 if (handshake->ciphersuite_info == NULL) { 1441 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE, 1442 MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE); 1443 return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE; 1444 } 1445 ssl->session_negotiate->ciphersuite = handshake->ciphersuite_info->id; 1446 1447 MBEDTLS_SSL_DEBUG_MSG(2, ("selected ciphersuite: %04x - %s", 1448 ((unsigned) handshake->ciphersuite_info->id), 1449 handshake->ciphersuite_info->name)); 1450 1451 /* ... 1452 * opaque legacy_compression_methods<1..2^8-1>; 1453 * ... 1454 */ 1455 if (p[0] != 1 || p[1] != MBEDTLS_SSL_COMPRESS_NULL) { 1456 MBEDTLS_SSL_DEBUG_MSG(1, ("bad legacy compression method")); 1457 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER, 1458 MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER); 1459 return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER; 1460 } 1461 p += 2; 1462 1463 /* ... 1464 * Extension extensions<8..2^16-1>; 1465 * ... 1466 * with Extension defined as: 1467 * struct { 1468 * ExtensionType extension_type; 1469 * opaque extension_data<0..2^16-1>; 1470 * } Extension; 1471 */ 1472 extensions_len = MBEDTLS_GET_UINT16_BE(p, 0); 1473 p += 2; 1474 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, extensions_len); 1475 extensions_end = p + extensions_len; 1476 1477 MBEDTLS_SSL_DEBUG_BUF(3, "client hello extensions", p, extensions_len); 1478 handshake->received_extensions = MBEDTLS_SSL_EXT_MASK_NONE; 1479 1480 while (p < extensions_end) { 1481 unsigned int extension_type; 1482 size_t extension_data_len; 1483 const unsigned char *extension_data_end; 1484 uint32_t allowed_exts = MBEDTLS_SSL_TLS1_3_ALLOWED_EXTS_OF_CH; 1485 1486 if (ssl->handshake->hello_retry_request_flag) { 1487 /* Do not accept early data extension in 2nd ClientHello */ 1488 allowed_exts &= ~MBEDTLS_SSL_EXT_MASK(EARLY_DATA); 1489 } 1490 1491 /* RFC 8446, section 4.2.11 1492 * 1493 * The "pre_shared_key" extension MUST be the last extension in the 1494 * ClientHello (this facilitates implementation as described below). 1495 * Servers MUST check that it is the last extension and otherwise fail 1496 * the handshake with an "illegal_parameter" alert. 1497 */ 1498 if (handshake->received_extensions & MBEDTLS_SSL_EXT_MASK(PRE_SHARED_KEY)) { 1499 MBEDTLS_SSL_DEBUG_MSG( 1500 3, ("pre_shared_key is not last extension.")); 1501 MBEDTLS_SSL_PEND_FATAL_ALERT( 1502 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER, 1503 MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER); 1504 return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER; 1505 } 1506 1507 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, extensions_end, 4); 1508 extension_type = MBEDTLS_GET_UINT16_BE(p, 0); 1509 extension_data_len = MBEDTLS_GET_UINT16_BE(p, 2); 1510 p += 4; 1511 1512 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, extensions_end, extension_data_len); 1513 extension_data_end = p + extension_data_len; 1514 1515 ret = mbedtls_ssl_tls13_check_received_extension( 1516 ssl, MBEDTLS_SSL_HS_CLIENT_HELLO, extension_type, 1517 allowed_exts); 1518 if (ret != 0) { 1519 return ret; 1520 } 1521 1522 switch (extension_type) { 1523#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) 1524 case MBEDTLS_TLS_EXT_SERVERNAME: 1525 MBEDTLS_SSL_DEBUG_MSG(3, ("found ServerName extension")); 1526 ret = mbedtls_ssl_parse_server_name_ext(ssl, p, 1527 extension_data_end); 1528 if (ret != 0) { 1529 MBEDTLS_SSL_DEBUG_RET( 1530 1, "mbedtls_ssl_parse_servername_ext", ret); 1531 return ret; 1532 } 1533 break; 1534#endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */ 1535 1536#if defined(PSA_WANT_ALG_ECDH) || defined(PSA_WANT_ALG_FFDH) 1537 case MBEDTLS_TLS_EXT_SUPPORTED_GROUPS: 1538 MBEDTLS_SSL_DEBUG_MSG(3, ("found supported group extension")); 1539 1540 /* Supported Groups Extension 1541 * 1542 * When sent by the client, the "supported_groups" extension 1543 * indicates the named groups which the client supports, 1544 * ordered from most preferred to least preferred. 1545 */ 1546 ret = ssl_tls13_parse_supported_groups_ext( 1547 ssl, p, extension_data_end); 1548 if (ret != 0) { 1549 MBEDTLS_SSL_DEBUG_RET( 1550 1, "ssl_tls13_parse_supported_groups_ext", ret); 1551 return ret; 1552 } 1553 1554 break; 1555#endif /* PSA_WANT_ALG_ECDH || PSA_WANT_ALG_FFDH*/ 1556 1557#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED) 1558 case MBEDTLS_TLS_EXT_KEY_SHARE: 1559 MBEDTLS_SSL_DEBUG_MSG(3, ("found key share extension")); 1560 1561 /* 1562 * Key Share Extension 1563 * 1564 * When sent by the client, the "key_share" extension 1565 * contains the endpoint's cryptographic parameters for 1566 * ECDHE/DHE key establishment methods. 1567 */ 1568 ret = ssl_tls13_parse_key_shares_ext( 1569 ssl, p, extension_data_end); 1570 if (ret == SSL_TLS1_3_PARSE_KEY_SHARES_EXT_NO_MATCH) { 1571 MBEDTLS_SSL_DEBUG_MSG(2, ("No usable share for key agreement.")); 1572 no_usable_share_for_key_agreement = 1; 1573 } 1574 1575 if (ret < 0) { 1576 MBEDTLS_SSL_DEBUG_RET( 1577 1, "ssl_tls13_parse_key_shares_ext", ret); 1578 return ret; 1579 } 1580 1581 break; 1582#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED */ 1583 1584 case MBEDTLS_TLS_EXT_SUPPORTED_VERSIONS: 1585 /* Already parsed */ 1586 break; 1587 1588#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) 1589 case MBEDTLS_TLS_EXT_PSK_KEY_EXCHANGE_MODES: 1590 MBEDTLS_SSL_DEBUG_MSG( 1591 3, ("found psk key exchange modes extension")); 1592 1593 ret = ssl_tls13_parse_key_exchange_modes_ext( 1594 ssl, p, extension_data_end); 1595 if (ret != 0) { 1596 MBEDTLS_SSL_DEBUG_RET( 1597 1, "ssl_tls13_parse_key_exchange_modes_ext", ret); 1598 return ret; 1599 } 1600 1601 break; 1602#endif 1603 1604 case MBEDTLS_TLS_EXT_PRE_SHARED_KEY: 1605 MBEDTLS_SSL_DEBUG_MSG(3, ("found pre_shared_key extension")); 1606 if ((handshake->received_extensions & 1607 MBEDTLS_SSL_EXT_MASK(PSK_KEY_EXCHANGE_MODES)) == 0) { 1608 MBEDTLS_SSL_PEND_FATAL_ALERT( 1609 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER, 1610 MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER); 1611 return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER; 1612 } 1613#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) 1614 /* Delay processing of the PSK identity once we have 1615 * found out which algorithms to use. We keep a pointer 1616 * to the buffer and the size for later processing. 1617 */ 1618 pre_shared_key_ext = p; 1619 pre_shared_key_ext_end = extension_data_end; 1620#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED */ 1621 break; 1622 1623#if defined(MBEDTLS_SSL_ALPN) 1624 case MBEDTLS_TLS_EXT_ALPN: 1625 MBEDTLS_SSL_DEBUG_MSG(3, ("found alpn extension")); 1626 1627 ret = mbedtls_ssl_parse_alpn_ext(ssl, p, extension_data_end); 1628 if (ret != 0) { 1629 MBEDTLS_SSL_DEBUG_RET( 1630 1, ("mbedtls_ssl_parse_alpn_ext"), ret); 1631 return ret; 1632 } 1633 break; 1634#endif /* MBEDTLS_SSL_ALPN */ 1635 1636#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED) 1637 case MBEDTLS_TLS_EXT_SIG_ALG: 1638 MBEDTLS_SSL_DEBUG_MSG(3, ("found signature_algorithms extension")); 1639 1640 ret = mbedtls_ssl_parse_sig_alg_ext( 1641 ssl, p, extension_data_end); 1642 if (ret != 0) { 1643 MBEDTLS_SSL_DEBUG_RET( 1644 1, "mbedtls_ssl_parse_sig_alg_ext", ret); 1645 return ret; 1646 } 1647 break; 1648#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */ 1649 1650#if defined(MBEDTLS_SSL_RECORD_SIZE_LIMIT) 1651 case MBEDTLS_TLS_EXT_RECORD_SIZE_LIMIT: 1652 MBEDTLS_SSL_DEBUG_MSG(3, ("found record_size_limit extension")); 1653 1654 ret = mbedtls_ssl_tls13_parse_record_size_limit_ext( 1655 ssl, p, extension_data_end); 1656 if (ret != 0) { 1657 MBEDTLS_SSL_DEBUG_RET( 1658 1, ("mbedtls_ssl_tls13_parse_record_size_limit_ext"), ret); 1659 return ret; 1660 } 1661 break; 1662#endif /* MBEDTLS_SSL_RECORD_SIZE_LIMIT */ 1663 1664 default: 1665 MBEDTLS_SSL_PRINT_EXT( 1666 3, MBEDTLS_SSL_HS_CLIENT_HELLO, 1667 extension_type, "( ignored )"); 1668 break; 1669 } 1670 1671 p += extension_data_len; 1672 } 1673 1674 MBEDTLS_SSL_PRINT_EXTS(3, MBEDTLS_SSL_HS_CLIENT_HELLO, 1675 handshake->received_extensions); 1676 1677 ret = mbedtls_ssl_add_hs_hdr_to_checksum(ssl, 1678 MBEDTLS_SSL_HS_CLIENT_HELLO, 1679 p - buf); 1680 if (0 != ret) { 1681 MBEDTLS_SSL_DEBUG_RET(1, ("mbedtls_ssl_add_hs_hdr_to_checksum"), ret); 1682 return ret; 1683 } 1684 1685#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) 1686 /* Update checksum with either 1687 * - The entire content of the CH message, if no PSK extension is present 1688 * - The content up to but excluding the PSK extension, if present. 1689 * Always parse the pre-shared-key extension when present in the 1690 * ClientHello even if some pre-requisites for PSK key exchange modes are 1691 * not met. That way we always validate the syntax of the extension. 1692 */ 1693 if (handshake->received_extensions & MBEDTLS_SSL_EXT_MASK(PRE_SHARED_KEY)) { 1694 ret = handshake->update_checksum(ssl, buf, 1695 pre_shared_key_ext - buf); 1696 if (0 != ret) { 1697 MBEDTLS_SSL_DEBUG_RET(1, ("update_checksum"), ret); 1698 return ret; 1699 } 1700 ret = ssl_tls13_parse_pre_shared_key_ext(ssl, 1701 pre_shared_key_ext, 1702 pre_shared_key_ext_end, 1703 cipher_suites, 1704 cipher_suites_end, 1705 &psk); 1706 if (ret == 0) { 1707 got_psk = 1; 1708 } else if (ret != MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY) { 1709 MBEDTLS_SSL_DEBUG_RET( 1710 1, "ssl_tls13_parse_pre_shared_key_ext", ret); 1711 return ret; 1712 } 1713 } else 1714#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED */ 1715 { 1716 ret = handshake->update_checksum(ssl, buf, p - buf); 1717 if (0 != ret) { 1718 MBEDTLS_SSL_DEBUG_RET(1, ("update_checksum"), ret); 1719 return ret; 1720 } 1721 } 1722 1723 /* 1724 * Determine the key exchange algorithm to use. 1725 * There are three types of key exchanges supported in TLS 1.3: 1726 * - (EC)DH with ECDSA, 1727 * - (EC)DH with PSK, 1728 * - plain PSK. 1729 * 1730 * The PSK-based key exchanges may additionally be used with 0-RTT. 1731 * 1732 * Our built-in order of preference is 1733 * 1 ) (EC)DHE-PSK Mode ( psk_ephemeral ) 1734 * 2 ) Certificate Mode ( ephemeral ) 1735 * 3 ) Plain PSK Mode ( psk ) 1736 */ 1737#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) 1738 if (got_psk && (psk.key_exchange_mode == 1739 MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL)) { 1740 handshake->key_exchange_mode = 1741 MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL; 1742 MBEDTLS_SSL_DEBUG_MSG(2, ("key exchange mode: psk_ephemeral")); 1743 1744 } else 1745#endif 1746 if (ssl_tls13_key_exchange_is_ephemeral_available(ssl)) { 1747 handshake->key_exchange_mode = 1748 MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL; 1749 MBEDTLS_SSL_DEBUG_MSG(2, ("key exchange mode: ephemeral")); 1750 1751 } 1752#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) 1753 else if (got_psk && (psk.key_exchange_mode == 1754 MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK)) { 1755 handshake->key_exchange_mode = MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK; 1756 MBEDTLS_SSL_DEBUG_MSG(2, ("key exchange mode: psk")); 1757 } 1758#endif 1759 else { 1760 MBEDTLS_SSL_DEBUG_MSG( 1761 1, 1762 ("ClientHello message misses mandatory extensions.")); 1763 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_MISSING_EXTENSION, 1764 MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER); 1765 return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER; 1766 } 1767 1768#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) 1769 if (handshake->key_exchange_mode & 1770 MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ALL) { 1771 handshake->ciphersuite_info = psk.ciphersuite_info; 1772 ssl->session_negotiate->ciphersuite = psk.ciphersuite_info->id; 1773 1774 MBEDTLS_SSL_DEBUG_MSG(2, ("Select PSK ciphersuite: %04x - %s", 1775 ((unsigned) psk.ciphersuite_info->id), 1776 psk.ciphersuite_info->name)); 1777 1778 if (psk.type == MBEDTLS_SSL_TLS1_3_PSK_RESUMPTION) { 1779 handshake->resume = 1; 1780 } 1781 } 1782#endif 1783 1784 if (handshake->key_exchange_mode != 1785 MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK) { 1786 hrr_required = (no_usable_share_for_key_agreement != 0); 1787 } 1788 1789 mbedtls_ssl_optimize_checksum(ssl, handshake->ciphersuite_info); 1790 1791 return hrr_required ? SSL_CLIENT_HELLO_HRR_REQUIRED : SSL_CLIENT_HELLO_OK; 1792} 1793 1794#if defined(MBEDTLS_SSL_EARLY_DATA) 1795static int ssl_tls13_check_early_data_requirements(mbedtls_ssl_context *ssl) 1796{ 1797 mbedtls_ssl_handshake_params *handshake = ssl->handshake; 1798 1799 if (ssl->conf->early_data_enabled == MBEDTLS_SSL_EARLY_DATA_DISABLED) { 1800 MBEDTLS_SSL_DEBUG_MSG( 1801 1, 1802 ("EarlyData: rejected, feature disabled in server configuration.")); 1803 return -1; 1804 } 1805 1806 if (!handshake->resume) { 1807 /* We currently support early data only in the case of PSKs established 1808 via a NewSessionTicket message thus in the case of a session 1809 resumption. */ 1810 MBEDTLS_SSL_DEBUG_MSG( 1811 1, ("EarlyData: rejected, not a session resumption.")); 1812 return -1; 1813 } 1814 1815 /* RFC 8446 4.2.10 1816 * 1817 * In order to accept early data, the server MUST have accepted a PSK cipher 1818 * suite and selected the first key offered in the client's "pre_shared_key" 1819 * extension. In addition, it MUST verify that the following values are the 1820 * same as those associated with the selected PSK: 1821 * - The TLS version number 1822 * - The selected cipher suite 1823 * - The selected ALPN [RFC7301] protocol, if any 1824 * 1825 * NOTE: 1826 * - The TLS version number is checked in 1827 * ssl_tls13_offered_psks_check_identity_match_ticket(). 1828 */ 1829 1830 if (handshake->selected_identity != 0) { 1831 MBEDTLS_SSL_DEBUG_MSG( 1832 1, ("EarlyData: rejected, the selected key in " 1833 "`pre_shared_key` is not the first one.")); 1834 return -1; 1835 } 1836 1837 if (handshake->ciphersuite_info->id != 1838 ssl->session_negotiate->ciphersuite) { 1839 MBEDTLS_SSL_DEBUG_MSG( 1840 1, ("EarlyData: rejected, the selected ciphersuite is not the one " 1841 "of the selected pre-shared key.")); 1842 return -1; 1843 1844 } 1845 1846 if (!mbedtls_ssl_tls13_session_ticket_allow_early_data(ssl->session_negotiate)) { 1847 MBEDTLS_SSL_DEBUG_MSG( 1848 1, 1849 ("EarlyData: rejected, early_data not allowed in ticket " 1850 "permission bits.")); 1851 return -1; 1852 } 1853 1854#if defined(MBEDTLS_SSL_ALPN) 1855 const char *alpn = mbedtls_ssl_get_alpn_protocol(ssl); 1856 size_t alpn_len; 1857 1858 if (alpn == NULL && ssl->session_negotiate->ticket_alpn == NULL) { 1859 return 0; 1860 } 1861 1862 if (alpn != NULL) { 1863 alpn_len = strlen(alpn); 1864 } 1865 1866 if (alpn == NULL || 1867 ssl->session_negotiate->ticket_alpn == NULL || 1868 alpn_len != strlen(ssl->session_negotiate->ticket_alpn) || 1869 (memcmp(alpn, ssl->session_negotiate->ticket_alpn, alpn_len) != 0)) { 1870 MBEDTLS_SSL_DEBUG_MSG(1, ("EarlyData: rejected, the selected ALPN is different " 1871 "from the one associated with the pre-shared key.")); 1872 return -1; 1873 } 1874#endif 1875 1876 return 0; 1877} 1878#endif /* MBEDTLS_SSL_EARLY_DATA */ 1879 1880/* Update the handshake state machine */ 1881 1882MBEDTLS_CHECK_RETURN_CRITICAL 1883static int ssl_tls13_postprocess_client_hello(mbedtls_ssl_context *ssl, 1884 int hrr_required) 1885{ 1886 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 1887 1888 /* 1889 * Server certificate selection 1890 */ 1891 if (ssl->conf->f_cert_cb && (ret = ssl->conf->f_cert_cb(ssl)) != 0) { 1892 MBEDTLS_SSL_DEBUG_RET(1, "f_cert_cb", ret); 1893 return ret; 1894 } 1895#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) 1896 ssl->handshake->sni_name = NULL; 1897 ssl->handshake->sni_name_len = 0; 1898#endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */ 1899 1900 ret = mbedtls_ssl_tls13_key_schedule_stage_early(ssl); 1901 if (ret != 0) { 1902 MBEDTLS_SSL_DEBUG_RET(1, 1903 "mbedtls_ssl_tls1_3_key_schedule_stage_early", ret); 1904 return ret; 1905 } 1906 1907#if defined(MBEDTLS_SSL_EARLY_DATA) 1908 if (ssl->handshake->received_extensions & MBEDTLS_SSL_EXT_MASK(EARLY_DATA)) { 1909 ssl->handshake->early_data_accepted = 1910 (!hrr_required) && (ssl_tls13_check_early_data_requirements(ssl) == 0); 1911 1912 if (ssl->handshake->early_data_accepted) { 1913 ret = mbedtls_ssl_tls13_compute_early_transform(ssl); 1914 if (ret != 0) { 1915 MBEDTLS_SSL_DEBUG_RET( 1916 1, "mbedtls_ssl_tls13_compute_early_transform", ret); 1917 return ret; 1918 } 1919 } else { 1920 ssl->discard_early_data_record = 1921 hrr_required ? 1922 MBEDTLS_SSL_EARLY_DATA_DISCARD : 1923 MBEDTLS_SSL_EARLY_DATA_TRY_TO_DEPROTECT_AND_DISCARD; 1924 } 1925 } 1926#else 1927 ((void) hrr_required); 1928#endif /* MBEDTLS_SSL_EARLY_DATA */ 1929 1930 return 0; 1931} 1932 1933/* 1934 * Main entry point from the state machine; orchestrates the otherfunctions. 1935 */ 1936 1937MBEDTLS_CHECK_RETURN_CRITICAL 1938static int ssl_tls13_process_client_hello(mbedtls_ssl_context *ssl) 1939{ 1940 1941 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 1942 unsigned char *buf = NULL; 1943 size_t buflen = 0; 1944 int parse_client_hello_ret; 1945 1946 MBEDTLS_SSL_DEBUG_MSG(2, ("=> parse client hello")); 1947 1948 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_tls13_fetch_handshake_msg( 1949 ssl, MBEDTLS_SSL_HS_CLIENT_HELLO, 1950 &buf, &buflen)); 1951 1952 MBEDTLS_SSL_PROC_CHK_NEG(ssl_tls13_parse_client_hello(ssl, buf, 1953 buf + buflen)); 1954 parse_client_hello_ret = ret; /* Store positive return value of 1955 * parse_client_hello, 1956 * as negative error codes are handled 1957 * by MBEDTLS_SSL_PROC_CHK_NEG. */ 1958 1959 /* 1960 * Version 1.2 of the protocol has to be used for the handshake. 1961 * If TLS 1.2 is not supported, abort the handshake. Otherwise, set the 1962 * ssl->keep_current_message flag for the ClientHello to be kept and parsed 1963 * as a TLS 1.2 ClientHello. We also change ssl->tls_version to 1964 * MBEDTLS_SSL_VERSION_TLS1_2 thus from now on mbedtls_ssl_handshake_step() 1965 * will dispatch to the TLS 1.2 state machine. 1966 */ 1967 if (SSL_CLIENT_HELLO_TLS1_2 == parse_client_hello_ret) { 1968 /* Check if server supports TLS 1.2 */ 1969 if (!mbedtls_ssl_conf_is_tls12_enabled(ssl->conf)) { 1970 MBEDTLS_SSL_DEBUG_MSG( 1971 1, ("TLS 1.2 not supported.")); 1972 MBEDTLS_SSL_PEND_FATAL_ALERT( 1973 MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION, 1974 MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION); 1975 return MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION; 1976 } 1977 ssl->keep_current_message = 1; 1978 ssl->tls_version = MBEDTLS_SSL_VERSION_TLS1_2; 1979 return 0; 1980 } 1981 1982 MBEDTLS_SSL_PROC_CHK( 1983 ssl_tls13_postprocess_client_hello(ssl, parse_client_hello_ret == 1984 SSL_CLIENT_HELLO_HRR_REQUIRED)); 1985 1986 if (SSL_CLIENT_HELLO_OK == parse_client_hello_ret) { 1987 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_SERVER_HELLO); 1988 } else { 1989 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_HELLO_RETRY_REQUEST); 1990 } 1991 1992cleanup: 1993 1994 MBEDTLS_SSL_DEBUG_MSG(2, ("<= parse client hello")); 1995 return ret; 1996} 1997 1998/* 1999 * Handler for MBEDTLS_SSL_SERVER_HELLO 2000 */ 2001MBEDTLS_CHECK_RETURN_CRITICAL 2002static int ssl_tls13_prepare_server_hello(mbedtls_ssl_context *ssl) 2003{ 2004 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2005 unsigned char *server_randbytes = 2006 ssl->handshake->randbytes + MBEDTLS_CLIENT_HELLO_RANDOM_LEN; 2007 2008 if ((ret = ssl->conf->f_rng(ssl->conf->p_rng, server_randbytes, 2009 MBEDTLS_SERVER_HELLO_RANDOM_LEN)) != 0) { 2010 MBEDTLS_SSL_DEBUG_RET(1, "f_rng", ret); 2011 return ret; 2012 } 2013 2014 MBEDTLS_SSL_DEBUG_BUF(3, "server hello, random bytes", server_randbytes, 2015 MBEDTLS_SERVER_HELLO_RANDOM_LEN); 2016 2017#if defined(MBEDTLS_HAVE_TIME) 2018 ssl->session_negotiate->start = mbedtls_time(NULL); 2019#endif /* MBEDTLS_HAVE_TIME */ 2020 2021 return ret; 2022} 2023 2024/* 2025 * ssl_tls13_write_server_hello_supported_versions_ext (): 2026 * 2027 * struct { 2028 * ProtocolVersion selected_version; 2029 * } SupportedVersions; 2030 */ 2031MBEDTLS_CHECK_RETURN_CRITICAL 2032static int ssl_tls13_write_server_hello_supported_versions_ext( 2033 mbedtls_ssl_context *ssl, 2034 unsigned char *buf, 2035 unsigned char *end, 2036 size_t *out_len) 2037{ 2038 *out_len = 0; 2039 2040 MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, write selected version")); 2041 2042 /* Check if we have space to write the extension: 2043 * - extension_type (2 bytes) 2044 * - extension_data_length (2 bytes) 2045 * - selected_version (2 bytes) 2046 */ 2047 MBEDTLS_SSL_CHK_BUF_PTR(buf, end, 6); 2048 2049 MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_SUPPORTED_VERSIONS, buf, 0); 2050 2051 MBEDTLS_PUT_UINT16_BE(2, buf, 2); 2052 2053 mbedtls_ssl_write_version(buf + 4, 2054 ssl->conf->transport, 2055 ssl->tls_version); 2056 2057 MBEDTLS_SSL_DEBUG_MSG(3, ("supported version: [%04x]", 2058 ssl->tls_version)); 2059 2060 *out_len = 6; 2061 2062 mbedtls_ssl_tls13_set_hs_sent_ext_mask( 2063 ssl, MBEDTLS_TLS_EXT_SUPPORTED_VERSIONS); 2064 2065 return 0; 2066} 2067 2068 2069 2070/* Generate and export a single key share. For hybrid KEMs, this can 2071 * be called multiple times with the different components of the hybrid. */ 2072MBEDTLS_CHECK_RETURN_CRITICAL 2073static int ssl_tls13_generate_and_write_key_share(mbedtls_ssl_context *ssl, 2074 uint16_t named_group, 2075 unsigned char *buf, 2076 unsigned char *end, 2077 size_t *out_len) 2078{ 2079 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2080 2081 *out_len = 0; 2082 2083#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED) 2084 if (mbedtls_ssl_tls13_named_group_is_ecdhe(named_group) || 2085 mbedtls_ssl_tls13_named_group_is_ffdh(named_group)) { 2086 ret = mbedtls_ssl_tls13_generate_and_write_xxdh_key_exchange( 2087 ssl, named_group, buf, end, out_len); 2088 if (ret != 0) { 2089 MBEDTLS_SSL_DEBUG_RET( 2090 1, "mbedtls_ssl_tls13_generate_and_write_xxdh_key_exchange", 2091 ret); 2092 return ret; 2093 } 2094 } else 2095#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED */ 2096 if (0 /* Other kinds of KEMs */) { 2097 } else { 2098 ((void) ssl); 2099 ((void) named_group); 2100 ((void) buf); 2101 ((void) end); 2102 ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR; 2103 } 2104 2105 return ret; 2106} 2107 2108/* 2109 * ssl_tls13_write_key_share_ext 2110 * 2111 * Structure of key_share extension in ServerHello: 2112 * 2113 * struct { 2114 * NamedGroup group; 2115 * opaque key_exchange<1..2^16-1>; 2116 * } KeyShareEntry; 2117 * struct { 2118 * KeyShareEntry server_share; 2119 * } KeyShareServerHello; 2120 */ 2121MBEDTLS_CHECK_RETURN_CRITICAL 2122static int ssl_tls13_write_key_share_ext(mbedtls_ssl_context *ssl, 2123 unsigned char *buf, 2124 unsigned char *end, 2125 size_t *out_len) 2126{ 2127 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2128 unsigned char *p = buf; 2129 uint16_t group = ssl->handshake->offered_group_id; 2130 unsigned char *server_share = buf + 4; 2131 size_t key_exchange_length; 2132 2133 *out_len = 0; 2134 2135 MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, adding key share extension")); 2136 2137 MBEDTLS_SSL_DEBUG_MSG(2, ("server hello, write selected_group: %s (%04x)", 2138 mbedtls_ssl_named_group_to_str(group), 2139 group)); 2140 2141 /* Check if we have space for header and length fields: 2142 * - extension_type (2 bytes) 2143 * - extension_data_length (2 bytes) 2144 * - group (2 bytes) 2145 * - key_exchange_length (2 bytes) 2146 */ 2147 MBEDTLS_SSL_CHK_BUF_PTR(p, end, 8); 2148 MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_KEY_SHARE, p, 0); 2149 MBEDTLS_PUT_UINT16_BE(group, server_share, 0); 2150 p += 8; 2151 2152 /* When we introduce PQC-ECDHE hybrids, we'll want to call this 2153 * function multiple times. */ 2154 ret = ssl_tls13_generate_and_write_key_share( 2155 ssl, group, server_share + 4, end, &key_exchange_length); 2156 if (ret != 0) { 2157 return ret; 2158 } 2159 p += key_exchange_length; 2160 2161 MBEDTLS_PUT_UINT16_BE(key_exchange_length, server_share + 2, 0); 2162 2163 MBEDTLS_PUT_UINT16_BE(p - server_share, buf, 2); 2164 2165 *out_len = p - buf; 2166 2167 mbedtls_ssl_tls13_set_hs_sent_ext_mask(ssl, MBEDTLS_TLS_EXT_KEY_SHARE); 2168 2169 return 0; 2170} 2171 2172MBEDTLS_CHECK_RETURN_CRITICAL 2173static int ssl_tls13_write_hrr_key_share_ext(mbedtls_ssl_context *ssl, 2174 unsigned char *buf, 2175 unsigned char *end, 2176 size_t *out_len) 2177{ 2178 uint16_t selected_group = ssl->handshake->hrr_selected_group; 2179 /* key_share Extension 2180 * 2181 * struct { 2182 * select (Handshake.msg_type) { 2183 * ... 2184 * case hello_retry_request: 2185 * NamedGroup selected_group; 2186 * ... 2187 * }; 2188 * } KeyShare; 2189 */ 2190 2191 *out_len = 0; 2192 2193 /* 2194 * For a pure PSK key exchange, there is no group to agree upon. The purpose 2195 * of the HRR is then to transmit a cookie to force the client to demonstrate 2196 * reachability at their apparent network address (primarily useful for DTLS). 2197 */ 2198 if (!mbedtls_ssl_tls13_key_exchange_mode_with_ephemeral(ssl)) { 2199 return 0; 2200 } 2201 2202 /* We should only send the key_share extension if the client's initial 2203 * key share was not acceptable. */ 2204 if (ssl->handshake->offered_group_id != 0) { 2205 MBEDTLS_SSL_DEBUG_MSG(4, ("Skip key_share extension in HRR")); 2206 return 0; 2207 } 2208 2209 if (selected_group == 0) { 2210 MBEDTLS_SSL_DEBUG_MSG(1, ("no matching named group found")); 2211 return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE; 2212 } 2213 2214 /* Check if we have enough space: 2215 * - extension_type (2 bytes) 2216 * - extension_data_length (2 bytes) 2217 * - selected_group (2 bytes) 2218 */ 2219 MBEDTLS_SSL_CHK_BUF_PTR(buf, end, 6); 2220 2221 MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_KEY_SHARE, buf, 0); 2222 MBEDTLS_PUT_UINT16_BE(2, buf, 2); 2223 MBEDTLS_PUT_UINT16_BE(selected_group, buf, 4); 2224 2225 MBEDTLS_SSL_DEBUG_MSG(3, 2226 ("HRR selected_group: %s (%x)", 2227 mbedtls_ssl_named_group_to_str(selected_group), 2228 selected_group)); 2229 2230 *out_len = 6; 2231 2232 mbedtls_ssl_tls13_set_hs_sent_ext_mask(ssl, MBEDTLS_TLS_EXT_KEY_SHARE); 2233 2234 return 0; 2235} 2236 2237/* 2238 * Structure of ServerHello message: 2239 * 2240 * struct { 2241 * ProtocolVersion legacy_version = 0x0303; // TLS v1.2 2242 * Random random; 2243 * opaque legacy_session_id_echo<0..32>; 2244 * CipherSuite cipher_suite; 2245 * uint8 legacy_compression_method = 0; 2246 * Extension extensions<6..2^16-1>; 2247 * } ServerHello; 2248 */ 2249MBEDTLS_CHECK_RETURN_CRITICAL 2250static int ssl_tls13_write_server_hello_body(mbedtls_ssl_context *ssl, 2251 unsigned char *buf, 2252 unsigned char *end, 2253 size_t *out_len, 2254 int is_hrr) 2255{ 2256 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2257 unsigned char *p = buf; 2258 unsigned char *p_extensions_len; 2259 size_t output_len; 2260 2261 *out_len = 0; 2262 ssl->handshake->sent_extensions = MBEDTLS_SSL_EXT_MASK_NONE; 2263 2264 /* ... 2265 * ProtocolVersion legacy_version = 0x0303; // TLS 1.2 2266 * ... 2267 * with ProtocolVersion defined as: 2268 * uint16 ProtocolVersion; 2269 */ 2270 MBEDTLS_SSL_CHK_BUF_PTR(p, end, 2); 2271 MBEDTLS_PUT_UINT16_BE(0x0303, p, 0); 2272 p += 2; 2273 2274 /* ... 2275 * Random random; 2276 * ... 2277 * with Random defined as: 2278 * opaque Random[MBEDTLS_SERVER_HELLO_RANDOM_LEN]; 2279 */ 2280 MBEDTLS_SSL_CHK_BUF_PTR(p, end, MBEDTLS_SERVER_HELLO_RANDOM_LEN); 2281 if (is_hrr) { 2282 memcpy(p, mbedtls_ssl_tls13_hello_retry_request_magic, 2283 MBEDTLS_SERVER_HELLO_RANDOM_LEN); 2284 } else { 2285 memcpy(p, &ssl->handshake->randbytes[MBEDTLS_CLIENT_HELLO_RANDOM_LEN], 2286 MBEDTLS_SERVER_HELLO_RANDOM_LEN); 2287 } 2288 MBEDTLS_SSL_DEBUG_BUF(3, "server hello, random bytes", 2289 p, MBEDTLS_SERVER_HELLO_RANDOM_LEN); 2290 p += MBEDTLS_SERVER_HELLO_RANDOM_LEN; 2291 2292 /* ... 2293 * opaque legacy_session_id_echo<0..32>; 2294 * ... 2295 */ 2296 MBEDTLS_SSL_CHK_BUF_PTR(p, end, 1 + ssl->session_negotiate->id_len); 2297 *p++ = (unsigned char) ssl->session_negotiate->id_len; 2298 if (ssl->session_negotiate->id_len > 0) { 2299 memcpy(p, &ssl->session_negotiate->id[0], 2300 ssl->session_negotiate->id_len); 2301 p += ssl->session_negotiate->id_len; 2302 2303 MBEDTLS_SSL_DEBUG_BUF(3, "session id", ssl->session_negotiate->id, 2304 ssl->session_negotiate->id_len); 2305 } 2306 2307 /* ... 2308 * CipherSuite cipher_suite; 2309 * ... 2310 * with CipherSuite defined as: 2311 * uint8 CipherSuite[2]; 2312 */ 2313 MBEDTLS_SSL_CHK_BUF_PTR(p, end, 2); 2314 MBEDTLS_PUT_UINT16_BE(ssl->session_negotiate->ciphersuite, p, 0); 2315 p += 2; 2316 MBEDTLS_SSL_DEBUG_MSG(3, 2317 ("server hello, chosen ciphersuite: %s ( id=%d )", 2318 mbedtls_ssl_get_ciphersuite_name( 2319 ssl->session_negotiate->ciphersuite), 2320 ssl->session_negotiate->ciphersuite)); 2321 2322 /* ... 2323 * uint8 legacy_compression_method = 0; 2324 * ... 2325 */ 2326 MBEDTLS_SSL_CHK_BUF_PTR(p, end, 1); 2327 *p++ = MBEDTLS_SSL_COMPRESS_NULL; 2328 2329 /* ... 2330 * Extension extensions<6..2^16-1>; 2331 * ... 2332 * struct { 2333 * ExtensionType extension_type; (2 bytes) 2334 * opaque extension_data<0..2^16-1>; 2335 * } Extension; 2336 */ 2337 MBEDTLS_SSL_CHK_BUF_PTR(p, end, 2); 2338 p_extensions_len = p; 2339 p += 2; 2340 2341 if ((ret = ssl_tls13_write_server_hello_supported_versions_ext( 2342 ssl, p, end, &output_len)) != 0) { 2343 MBEDTLS_SSL_DEBUG_RET( 2344 1, "ssl_tls13_write_server_hello_supported_versions_ext", ret); 2345 return ret; 2346 } 2347 p += output_len; 2348 2349 if (mbedtls_ssl_tls13_key_exchange_mode_with_ephemeral(ssl)) { 2350 if (is_hrr) { 2351 ret = ssl_tls13_write_hrr_key_share_ext(ssl, p, end, &output_len); 2352 } else { 2353 ret = ssl_tls13_write_key_share_ext(ssl, p, end, &output_len); 2354 } 2355 if (ret != 0) { 2356 return ret; 2357 } 2358 p += output_len; 2359 } 2360 2361#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) 2362 if (!is_hrr && mbedtls_ssl_tls13_key_exchange_mode_with_psk(ssl)) { 2363 ret = ssl_tls13_write_server_pre_shared_key_ext(ssl, p, end, &output_len); 2364 if (ret != 0) { 2365 MBEDTLS_SSL_DEBUG_RET(1, "ssl_tls13_write_server_pre_shared_key_ext", 2366 ret); 2367 return ret; 2368 } 2369 p += output_len; 2370 } 2371#endif 2372 2373 MBEDTLS_PUT_UINT16_BE(p - p_extensions_len - 2, p_extensions_len, 0); 2374 2375 MBEDTLS_SSL_DEBUG_BUF(4, "server hello extensions", 2376 p_extensions_len, p - p_extensions_len); 2377 2378 *out_len = p - buf; 2379 2380 MBEDTLS_SSL_DEBUG_BUF(3, "server hello", buf, *out_len); 2381 2382 MBEDTLS_SSL_PRINT_EXTS( 2383 3, is_hrr ? MBEDTLS_SSL_TLS1_3_HS_HELLO_RETRY_REQUEST : 2384 MBEDTLS_SSL_HS_SERVER_HELLO, 2385 ssl->handshake->sent_extensions); 2386 2387 return ret; 2388} 2389 2390MBEDTLS_CHECK_RETURN_CRITICAL 2391static int ssl_tls13_finalize_server_hello(mbedtls_ssl_context *ssl) 2392{ 2393 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2394 ret = mbedtls_ssl_tls13_compute_handshake_transform(ssl); 2395 if (ret != 0) { 2396 MBEDTLS_SSL_DEBUG_RET(1, 2397 "mbedtls_ssl_tls13_compute_handshake_transform", 2398 ret); 2399 return ret; 2400 } 2401 2402 return ret; 2403} 2404 2405MBEDTLS_CHECK_RETURN_CRITICAL 2406static int ssl_tls13_write_server_hello(mbedtls_ssl_context *ssl) 2407{ 2408 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2409 unsigned char *buf; 2410 size_t buf_len, msg_len; 2411 2412 MBEDTLS_SSL_DEBUG_MSG(2, ("=> write server hello")); 2413 2414 MBEDTLS_SSL_PROC_CHK(ssl_tls13_prepare_server_hello(ssl)); 2415 2416 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_start_handshake_msg( 2417 ssl, MBEDTLS_SSL_HS_SERVER_HELLO, &buf, &buf_len)); 2418 2419 MBEDTLS_SSL_PROC_CHK(ssl_tls13_write_server_hello_body(ssl, buf, 2420 buf + buf_len, 2421 &msg_len, 2422 0)); 2423 2424 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum( 2425 ssl, MBEDTLS_SSL_HS_SERVER_HELLO, buf, msg_len)); 2426 2427 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_finish_handshake_msg( 2428 ssl, buf_len, msg_len)); 2429 2430 MBEDTLS_SSL_PROC_CHK(ssl_tls13_finalize_server_hello(ssl)); 2431 2432#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE) 2433 /* The server sends a dummy change_cipher_spec record immediately 2434 * after its first handshake message. This may either be after 2435 * a ServerHello or a HelloRetryRequest. 2436 */ 2437 mbedtls_ssl_handshake_set_state( 2438 ssl, MBEDTLS_SSL_SERVER_CCS_AFTER_SERVER_HELLO); 2439#else 2440 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_ENCRYPTED_EXTENSIONS); 2441#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */ 2442 2443cleanup: 2444 2445 MBEDTLS_SSL_DEBUG_MSG(2, ("<= write server hello")); 2446 return ret; 2447} 2448 2449 2450/* 2451 * Handler for MBEDTLS_SSL_HELLO_RETRY_REQUEST 2452 */ 2453MBEDTLS_CHECK_RETURN_CRITICAL 2454static int ssl_tls13_prepare_hello_retry_request(mbedtls_ssl_context *ssl) 2455{ 2456 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2457 if (ssl->handshake->hello_retry_request_flag) { 2458 MBEDTLS_SSL_DEBUG_MSG(1, ("Too many HRRs")); 2459 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE, 2460 MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE); 2461 return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE; 2462 } 2463 2464 /* 2465 * Create stateless transcript hash for HRR 2466 */ 2467 MBEDTLS_SSL_DEBUG_MSG(4, ("Reset transcript for HRR")); 2468 ret = mbedtls_ssl_reset_transcript_for_hrr(ssl); 2469 if (ret != 0) { 2470 MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_reset_transcript_for_hrr", ret); 2471 return ret; 2472 } 2473 mbedtls_ssl_session_reset_msg_layer(ssl, 0); 2474 2475 return 0; 2476} 2477 2478MBEDTLS_CHECK_RETURN_CRITICAL 2479static int ssl_tls13_write_hello_retry_request(mbedtls_ssl_context *ssl) 2480{ 2481 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2482 unsigned char *buf; 2483 size_t buf_len, msg_len; 2484 2485 MBEDTLS_SSL_DEBUG_MSG(2, ("=> write hello retry request")); 2486 2487 MBEDTLS_SSL_PROC_CHK(ssl_tls13_prepare_hello_retry_request(ssl)); 2488 2489 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_start_handshake_msg( 2490 ssl, MBEDTLS_SSL_HS_SERVER_HELLO, 2491 &buf, &buf_len)); 2492 2493 MBEDTLS_SSL_PROC_CHK(ssl_tls13_write_server_hello_body(ssl, buf, 2494 buf + buf_len, 2495 &msg_len, 2496 1)); 2497 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum( 2498 ssl, MBEDTLS_SSL_HS_SERVER_HELLO, buf, msg_len)); 2499 2500 2501 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_finish_handshake_msg(ssl, buf_len, 2502 msg_len)); 2503 2504 ssl->handshake->hello_retry_request_flag = 1; 2505 2506#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE) 2507 /* The server sends a dummy change_cipher_spec record immediately 2508 * after its first handshake message. This may either be after 2509 * a ServerHello or a HelloRetryRequest. 2510 */ 2511 mbedtls_ssl_handshake_set_state( 2512 ssl, MBEDTLS_SSL_SERVER_CCS_AFTER_HELLO_RETRY_REQUEST); 2513#else 2514 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_CLIENT_HELLO); 2515#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */ 2516 2517cleanup: 2518 MBEDTLS_SSL_DEBUG_MSG(2, ("<= write hello retry request")); 2519 return ret; 2520} 2521 2522/* 2523 * Handler for MBEDTLS_SSL_ENCRYPTED_EXTENSIONS 2524 */ 2525 2526/* 2527 * struct { 2528 * Extension extensions<0..2 ^ 16 - 1>; 2529 * } EncryptedExtensions; 2530 * 2531 */ 2532MBEDTLS_CHECK_RETURN_CRITICAL 2533static int ssl_tls13_write_encrypted_extensions_body(mbedtls_ssl_context *ssl, 2534 unsigned char *buf, 2535 unsigned char *end, 2536 size_t *out_len) 2537{ 2538 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2539 unsigned char *p = buf; 2540 size_t extensions_len = 0; 2541 unsigned char *p_extensions_len; 2542 size_t output_len; 2543 2544 *out_len = 0; 2545 2546 MBEDTLS_SSL_CHK_BUF_PTR(p, end, 2); 2547 p_extensions_len = p; 2548 p += 2; 2549 2550 ((void) ssl); 2551 ((void) ret); 2552 ((void) output_len); 2553 2554#if defined(MBEDTLS_SSL_ALPN) 2555 ret = mbedtls_ssl_write_alpn_ext(ssl, p, end, &output_len); 2556 if (ret != 0) { 2557 return ret; 2558 } 2559 p += output_len; 2560#endif /* MBEDTLS_SSL_ALPN */ 2561 2562#if defined(MBEDTLS_SSL_EARLY_DATA) 2563 if (ssl->handshake->early_data_accepted) { 2564 ret = mbedtls_ssl_tls13_write_early_data_ext( 2565 ssl, 0, p, end, &output_len); 2566 if (ret != 0) { 2567 return ret; 2568 } 2569 p += output_len; 2570 } 2571#endif /* MBEDTLS_SSL_EARLY_DATA */ 2572 2573#if defined(MBEDTLS_SSL_RECORD_SIZE_LIMIT) 2574 if (ssl->handshake->received_extensions & MBEDTLS_SSL_EXT_MASK(RECORD_SIZE_LIMIT)) { 2575 ret = mbedtls_ssl_tls13_write_record_size_limit_ext( 2576 ssl, p, end, &output_len); 2577 if (ret != 0) { 2578 return ret; 2579 } 2580 p += output_len; 2581 } 2582#endif 2583 2584 extensions_len = (p - p_extensions_len) - 2; 2585 MBEDTLS_PUT_UINT16_BE(extensions_len, p_extensions_len, 0); 2586 2587 *out_len = p - buf; 2588 2589 MBEDTLS_SSL_DEBUG_BUF(4, "encrypted extensions", buf, *out_len); 2590 2591 MBEDTLS_SSL_PRINT_EXTS( 2592 3, MBEDTLS_SSL_HS_ENCRYPTED_EXTENSIONS, ssl->handshake->sent_extensions); 2593 2594 return 0; 2595} 2596 2597MBEDTLS_CHECK_RETURN_CRITICAL 2598static int ssl_tls13_write_encrypted_extensions(mbedtls_ssl_context *ssl) 2599{ 2600 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2601 unsigned char *buf; 2602 size_t buf_len, msg_len; 2603 2604 mbedtls_ssl_set_outbound_transform(ssl, 2605 ssl->handshake->transform_handshake); 2606 MBEDTLS_SSL_DEBUG_MSG( 2607 3, ("switching to handshake transform for outbound data")); 2608 2609 MBEDTLS_SSL_DEBUG_MSG(2, ("=> write encrypted extensions")); 2610 2611 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_start_handshake_msg( 2612 ssl, MBEDTLS_SSL_HS_ENCRYPTED_EXTENSIONS, 2613 &buf, &buf_len)); 2614 2615 MBEDTLS_SSL_PROC_CHK(ssl_tls13_write_encrypted_extensions_body( 2616 ssl, buf, buf + buf_len, &msg_len)); 2617 2618 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum( 2619 ssl, MBEDTLS_SSL_HS_ENCRYPTED_EXTENSIONS, 2620 buf, msg_len)); 2621 2622 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_finish_handshake_msg( 2623 ssl, buf_len, msg_len)); 2624 2625#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED) 2626 if (mbedtls_ssl_tls13_key_exchange_mode_with_psk(ssl)) { 2627 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_SERVER_FINISHED); 2628 } else { 2629 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_CERTIFICATE_REQUEST); 2630 } 2631#else 2632 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_SERVER_FINISHED); 2633#endif 2634 2635cleanup: 2636 2637 MBEDTLS_SSL_DEBUG_MSG(2, ("<= write encrypted extensions")); 2638 return ret; 2639} 2640 2641#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED) 2642#define SSL_CERTIFICATE_REQUEST_SEND_REQUEST 0 2643#define SSL_CERTIFICATE_REQUEST_SKIP 1 2644/* Coordination: 2645 * Check whether a CertificateRequest message should be written. 2646 * Returns a negative code on failure, or 2647 * - SSL_CERTIFICATE_REQUEST_SEND_REQUEST 2648 * - SSL_CERTIFICATE_REQUEST_SKIP 2649 * indicating if the writing of the CertificateRequest 2650 * should be skipped or not. 2651 */ 2652MBEDTLS_CHECK_RETURN_CRITICAL 2653static int ssl_tls13_certificate_request_coordinate(mbedtls_ssl_context *ssl) 2654{ 2655 int authmode; 2656 2657#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) 2658 if (ssl->handshake->sni_authmode != MBEDTLS_SSL_VERIFY_UNSET) { 2659 authmode = ssl->handshake->sni_authmode; 2660 } else 2661#endif 2662 authmode = ssl->conf->authmode; 2663 2664 if (authmode == MBEDTLS_SSL_VERIFY_NONE) { 2665 ssl->session_negotiate->verify_result = MBEDTLS_X509_BADCERT_SKIP_VERIFY; 2666 return SSL_CERTIFICATE_REQUEST_SKIP; 2667 } 2668 2669 ssl->handshake->certificate_request_sent = 1; 2670 2671 return SSL_CERTIFICATE_REQUEST_SEND_REQUEST; 2672} 2673 2674/* 2675 * struct { 2676 * opaque certificate_request_context<0..2^8-1>; 2677 * Extension extensions<2..2^16-1>; 2678 * } CertificateRequest; 2679 * 2680 */ 2681MBEDTLS_CHECK_RETURN_CRITICAL 2682static int ssl_tls13_write_certificate_request_body(mbedtls_ssl_context *ssl, 2683 unsigned char *buf, 2684 const unsigned char *end, 2685 size_t *out_len) 2686{ 2687 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2688 unsigned char *p = buf; 2689 size_t output_len = 0; 2690 unsigned char *p_extensions_len; 2691 2692 *out_len = 0; 2693 2694 /* Check if we have enough space: 2695 * - certificate_request_context (1 byte) 2696 * - extensions length (2 bytes) 2697 */ 2698 MBEDTLS_SSL_CHK_BUF_PTR(p, end, 3); 2699 2700 /* 2701 * Write certificate_request_context 2702 */ 2703 /* 2704 * We use a zero length context for the normal handshake 2705 * messages. For post-authentication handshake messages 2706 * this request context would be set to a non-zero value. 2707 */ 2708 *p++ = 0x0; 2709 2710 /* 2711 * Write extensions 2712 */ 2713 /* The extensions must contain the signature_algorithms. */ 2714 p_extensions_len = p; 2715 p += 2; 2716 ret = mbedtls_ssl_write_sig_alg_ext(ssl, p, end, &output_len); 2717 if (ret != 0) { 2718 return ret; 2719 } 2720 2721 p += output_len; 2722 MBEDTLS_PUT_UINT16_BE(p - p_extensions_len - 2, p_extensions_len, 0); 2723 2724 *out_len = p - buf; 2725 2726 MBEDTLS_SSL_PRINT_EXTS( 2727 3, MBEDTLS_SSL_HS_CERTIFICATE_REQUEST, ssl->handshake->sent_extensions); 2728 2729 return 0; 2730} 2731 2732MBEDTLS_CHECK_RETURN_CRITICAL 2733static int ssl_tls13_write_certificate_request(mbedtls_ssl_context *ssl) 2734{ 2735 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2736 2737 MBEDTLS_SSL_DEBUG_MSG(2, ("=> write certificate request")); 2738 2739 MBEDTLS_SSL_PROC_CHK_NEG(ssl_tls13_certificate_request_coordinate(ssl)); 2740 2741 if (ret == SSL_CERTIFICATE_REQUEST_SEND_REQUEST) { 2742 unsigned char *buf; 2743 size_t buf_len, msg_len; 2744 2745 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_start_handshake_msg( 2746 ssl, MBEDTLS_SSL_HS_CERTIFICATE_REQUEST, 2747 &buf, &buf_len)); 2748 2749 MBEDTLS_SSL_PROC_CHK(ssl_tls13_write_certificate_request_body( 2750 ssl, buf, buf + buf_len, &msg_len)); 2751 2752 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum( 2753 ssl, MBEDTLS_SSL_HS_CERTIFICATE_REQUEST, 2754 buf, msg_len)); 2755 2756 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_finish_handshake_msg( 2757 ssl, buf_len, msg_len)); 2758 } else if (ret == SSL_CERTIFICATE_REQUEST_SKIP) { 2759 MBEDTLS_SSL_DEBUG_MSG(2, ("<= skip write certificate request")); 2760 ret = 0; 2761 } else { 2762 MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen")); 2763 ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR; 2764 goto cleanup; 2765 } 2766 2767 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_SERVER_CERTIFICATE); 2768cleanup: 2769 2770 MBEDTLS_SSL_DEBUG_MSG(2, ("<= write certificate request")); 2771 return ret; 2772} 2773 2774/* 2775 * Handler for MBEDTLS_SSL_SERVER_CERTIFICATE 2776 */ 2777MBEDTLS_CHECK_RETURN_CRITICAL 2778static int ssl_tls13_write_server_certificate(mbedtls_ssl_context *ssl) 2779{ 2780 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2781 2782#if defined(MBEDTLS_X509_CRT_PARSE_C) 2783 if ((ssl_tls13_pick_key_cert(ssl) != 0) || 2784 mbedtls_ssl_own_cert(ssl) == NULL) { 2785 MBEDTLS_SSL_DEBUG_MSG(2, ("No certificate available.")); 2786 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE, 2787 MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE); 2788 return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE; 2789 } 2790#endif /* MBEDTLS_X509_CRT_PARSE_C */ 2791 2792 ret = mbedtls_ssl_tls13_write_certificate(ssl); 2793 if (ret != 0) { 2794 return ret; 2795 } 2796 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_CERTIFICATE_VERIFY); 2797 return 0; 2798} 2799 2800/* 2801 * Handler for MBEDTLS_SSL_CERTIFICATE_VERIFY 2802 */ 2803MBEDTLS_CHECK_RETURN_CRITICAL 2804static int ssl_tls13_write_certificate_verify(mbedtls_ssl_context *ssl) 2805{ 2806 int ret = mbedtls_ssl_tls13_write_certificate_verify(ssl); 2807 if (ret != 0) { 2808 return ret; 2809 } 2810 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_SERVER_FINISHED); 2811 return 0; 2812} 2813#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */ 2814 2815/* 2816 * RFC 8446 section A.2 2817 * 2818 * | Send ServerHello 2819 * | K_send = handshake 2820 * | Send EncryptedExtensions 2821 * | [Send CertificateRequest] 2822 * Can send | [Send Certificate + CertificateVerify] 2823 * app data | Send Finished 2824 * after --> | K_send = application 2825 * here +--------+--------+ 2826 * No 0-RTT | | 0-RTT 2827 * | | 2828 * K_recv = handshake | | K_recv = early data 2829 * [Skip decrypt errors] | +------> WAIT_EOED -+ 2830 * | | Recv | | Recv EndOfEarlyData 2831 * | | early data | | K_recv = handshake 2832 * | +------------+ | 2833 * | | 2834 * +> WAIT_FLIGHT2 <--------+ 2835 * | 2836 * +--------+--------+ 2837 * No auth | | Client auth 2838 * | | 2839 * | v 2840 * | WAIT_CERT 2841 * | Recv | | Recv Certificate 2842 * | empty | v 2843 * | Certificate | WAIT_CV 2844 * | | | Recv 2845 * | v | CertificateVerify 2846 * +-> WAIT_FINISHED <---+ 2847 * | Recv Finished 2848 * 2849 * 2850 * The following function handles the state changes after WAIT_FLIGHT2 in the 2851 * above diagram. We are not going to receive early data related messages 2852 * anymore, prepare to receive the first handshake message of the client 2853 * second flight. 2854 */ 2855static void ssl_tls13_prepare_for_handshake_second_flight( 2856 mbedtls_ssl_context *ssl) 2857{ 2858 if (ssl->handshake->certificate_request_sent) { 2859 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_CLIENT_CERTIFICATE); 2860 } else { 2861 MBEDTLS_SSL_DEBUG_MSG(2, ("skip parse certificate")); 2862 MBEDTLS_SSL_DEBUG_MSG(2, ("skip parse certificate verify")); 2863 2864 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_CLIENT_FINISHED); 2865 } 2866} 2867 2868/* 2869 * Handler for MBEDTLS_SSL_SERVER_FINISHED 2870 */ 2871MBEDTLS_CHECK_RETURN_CRITICAL 2872static int ssl_tls13_write_server_finished(mbedtls_ssl_context *ssl) 2873{ 2874 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2875 2876 ret = mbedtls_ssl_tls13_write_finished_message(ssl); 2877 if (ret != 0) { 2878 return ret; 2879 } 2880 2881 ret = mbedtls_ssl_tls13_compute_application_transform(ssl); 2882 if (ret != 0) { 2883 MBEDTLS_SSL_PEND_FATAL_ALERT( 2884 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE, 2885 MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE); 2886 return ret; 2887 } 2888 2889#if defined(MBEDTLS_SSL_EARLY_DATA) 2890 if (ssl->handshake->early_data_accepted) { 2891 /* See RFC 8446 section A.2 for more information */ 2892 MBEDTLS_SSL_DEBUG_MSG( 2893 1, ("Switch to early keys for inbound traffic. " 2894 "( K_recv = early data )")); 2895 mbedtls_ssl_set_inbound_transform( 2896 ssl, ssl->handshake->transform_earlydata); 2897 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_END_OF_EARLY_DATA); 2898 return 0; 2899 } 2900#endif /* MBEDTLS_SSL_EARLY_DATA */ 2901 MBEDTLS_SSL_DEBUG_MSG( 2902 1, ("Switch to handshake keys for inbound traffic " 2903 "( K_recv = handshake )")); 2904 mbedtls_ssl_set_inbound_transform(ssl, ssl->handshake->transform_handshake); 2905 2906 ssl_tls13_prepare_for_handshake_second_flight(ssl); 2907 2908 return 0; 2909} 2910 2911#if defined(MBEDTLS_SSL_EARLY_DATA) 2912/* 2913 * Handler for MBEDTLS_SSL_END_OF_EARLY_DATA 2914 */ 2915#define SSL_GOT_END_OF_EARLY_DATA 0 2916#define SSL_GOT_EARLY_DATA 1 2917/* Coordination: 2918 * Deals with the ambiguity of not knowing if the next message is an 2919 * EndOfEarlyData message or an application message containing early data. 2920 * Returns a negative code on failure, or 2921 * - SSL_GOT_END_OF_EARLY_DATA 2922 * - SSL_GOT_EARLY_DATA 2923 * indicating which message is received. 2924 */ 2925MBEDTLS_CHECK_RETURN_CRITICAL 2926static int ssl_tls13_end_of_early_data_coordinate(mbedtls_ssl_context *ssl) 2927{ 2928 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2929 2930 if ((ret = mbedtls_ssl_read_record(ssl, 0)) != 0) { 2931 MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_read_record", ret); 2932 return ret; 2933 } 2934 ssl->keep_current_message = 1; 2935 2936 if (ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE && 2937 ssl->in_msg[0] == MBEDTLS_SSL_HS_END_OF_EARLY_DATA) { 2938 MBEDTLS_SSL_DEBUG_MSG(3, ("Received an end_of_early_data message.")); 2939 return SSL_GOT_END_OF_EARLY_DATA; 2940 } 2941 2942 if (ssl->in_msgtype == MBEDTLS_SSL_MSG_APPLICATION_DATA) { 2943 if (ssl->in_offt == NULL) { 2944 MBEDTLS_SSL_DEBUG_MSG(3, ("Received early data")); 2945 /* Set the reading pointer */ 2946 ssl->in_offt = ssl->in_msg; 2947 ret = mbedtls_ssl_tls13_check_early_data_len(ssl, ssl->in_msglen); 2948 if (ret != 0) { 2949 return ret; 2950 } 2951 } 2952 return SSL_GOT_EARLY_DATA; 2953 } 2954 2955 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE, 2956 MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE); 2957 return MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE; 2958} 2959 2960MBEDTLS_CHECK_RETURN_CRITICAL 2961static int ssl_tls13_parse_end_of_early_data(mbedtls_ssl_context *ssl, 2962 const unsigned char *buf, 2963 const unsigned char *end) 2964{ 2965 /* RFC 8446 section 4.5 2966 * 2967 * struct {} EndOfEarlyData; 2968 */ 2969 if (buf != end) { 2970 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR, 2971 MBEDTLS_ERR_SSL_DECODE_ERROR); 2972 return MBEDTLS_ERR_SSL_DECODE_ERROR; 2973 } 2974 return 0; 2975} 2976 2977/* 2978 * RFC 8446 section A.2 2979 * 2980 * | Send ServerHello 2981 * | K_send = handshake 2982 * | Send EncryptedExtensions 2983 * | [Send CertificateRequest] 2984 * Can send | [Send Certificate + CertificateVerify] 2985 * app data | Send Finished 2986 * after --> | K_send = application 2987 * here +--------+--------+ 2988 * No 0-RTT | | 0-RTT 2989 * | | 2990 * K_recv = handshake | | K_recv = early data 2991 * [Skip decrypt errors] | +------> WAIT_EOED -+ 2992 * | | Recv | | Recv EndOfEarlyData 2993 * | | early data | | K_recv = handshake 2994 * | +------------+ | 2995 * | | 2996 * +> WAIT_FLIGHT2 <--------+ 2997 * | 2998 * +--------+--------+ 2999 * No auth | | Client auth 3000 * | | 3001 * | v 3002 * | WAIT_CERT 3003 * | Recv | | Recv Certificate 3004 * | empty | v 3005 * | Certificate | WAIT_CV 3006 * | | | Recv 3007 * | v | CertificateVerify 3008 * +-> WAIT_FINISHED <---+ 3009 * | Recv Finished 3010 * 3011 * The function handles actions and state changes from 0-RTT to WAIT_FLIGHT2 in 3012 * the above diagram. 3013 */ 3014MBEDTLS_CHECK_RETURN_CRITICAL 3015static int ssl_tls13_process_end_of_early_data(mbedtls_ssl_context *ssl) 3016{ 3017 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 3018 3019 MBEDTLS_SSL_DEBUG_MSG(2, ("=> ssl_tls13_process_end_of_early_data")); 3020 3021 MBEDTLS_SSL_PROC_CHK_NEG(ssl_tls13_end_of_early_data_coordinate(ssl)); 3022 3023 if (ret == SSL_GOT_END_OF_EARLY_DATA) { 3024 unsigned char *buf; 3025 size_t buf_len; 3026 3027 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_tls13_fetch_handshake_msg( 3028 ssl, MBEDTLS_SSL_HS_END_OF_EARLY_DATA, 3029 &buf, &buf_len)); 3030 3031 MBEDTLS_SSL_PROC_CHK(ssl_tls13_parse_end_of_early_data( 3032 ssl, buf, buf + buf_len)); 3033 3034 MBEDTLS_SSL_DEBUG_MSG( 3035 1, ("Switch to handshake keys for inbound traffic" 3036 "( K_recv = handshake )")); 3037 mbedtls_ssl_set_inbound_transform( 3038 ssl, ssl->handshake->transform_handshake); 3039 3040 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum( 3041 ssl, MBEDTLS_SSL_HS_END_OF_EARLY_DATA, 3042 buf, buf_len)); 3043 3044 ssl_tls13_prepare_for_handshake_second_flight(ssl); 3045 3046 } else if (ret == SSL_GOT_EARLY_DATA) { 3047 ret = MBEDTLS_ERR_SSL_RECEIVED_EARLY_DATA; 3048 goto cleanup; 3049 } else { 3050 MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen")); 3051 ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR; 3052 goto cleanup; 3053 } 3054 3055cleanup: 3056 MBEDTLS_SSL_DEBUG_MSG(2, ("<= ssl_tls13_process_end_of_early_data")); 3057 return ret; 3058} 3059#endif /* MBEDTLS_SSL_EARLY_DATA */ 3060 3061/* 3062 * Handler for MBEDTLS_SSL_CLIENT_FINISHED 3063 */ 3064MBEDTLS_CHECK_RETURN_CRITICAL 3065static int ssl_tls13_process_client_finished(mbedtls_ssl_context *ssl) 3066{ 3067 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 3068 3069 ret = mbedtls_ssl_tls13_process_finished_message(ssl); 3070 if (ret != 0) { 3071 return ret; 3072 } 3073 3074 ret = mbedtls_ssl_tls13_compute_resumption_master_secret(ssl); 3075 if (ret != 0) { 3076 MBEDTLS_SSL_DEBUG_RET( 3077 1, "mbedtls_ssl_tls13_compute_resumption_master_secret", ret); 3078 } 3079 3080 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_HANDSHAKE_WRAPUP); 3081 return 0; 3082} 3083 3084/* 3085 * Handler for MBEDTLS_SSL_HANDSHAKE_WRAPUP 3086 */ 3087MBEDTLS_CHECK_RETURN_CRITICAL 3088static int ssl_tls13_handshake_wrapup(mbedtls_ssl_context *ssl) 3089{ 3090 MBEDTLS_SSL_DEBUG_MSG(2, ("handshake: done")); 3091 3092 mbedtls_ssl_tls13_handshake_wrapup(ssl); 3093 3094#if defined(MBEDTLS_SSL_SESSION_TICKETS) && \ 3095 defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) 3096/* TODO: Remove the check of SOME_PSK_ENABLED since SESSION_TICKETS requires 3097 * SOME_PSK_ENABLED to be enabled. Here is just to make CI happy. It is 3098 * expected to be resolved with issue#6395. 3099 */ 3100 /* Sent NewSessionTicket message only when client supports PSK */ 3101 if (mbedtls_ssl_tls13_is_some_psk_supported(ssl)) { 3102 mbedtls_ssl_handshake_set_state( 3103 ssl, MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET); 3104 } else 3105#endif 3106 { 3107 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_HANDSHAKE_OVER); 3108 } 3109 return 0; 3110} 3111 3112/* 3113 * Handler for MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET 3114 */ 3115#define SSL_NEW_SESSION_TICKET_SKIP 0 3116#define SSL_NEW_SESSION_TICKET_WRITE 1 3117MBEDTLS_CHECK_RETURN_CRITICAL 3118static int ssl_tls13_write_new_session_ticket_coordinate(mbedtls_ssl_context *ssl) 3119{ 3120 /* Check whether the use of session tickets is enabled */ 3121 if (ssl->conf->f_ticket_write == NULL) { 3122 MBEDTLS_SSL_DEBUG_MSG(2, ("NewSessionTicket: disabled," 3123 " callback is not set")); 3124 return SSL_NEW_SESSION_TICKET_SKIP; 3125 } 3126 if (ssl->conf->new_session_tickets_count == 0) { 3127 MBEDTLS_SSL_DEBUG_MSG(2, ("NewSessionTicket: disabled," 3128 " configured count is zero")); 3129 return SSL_NEW_SESSION_TICKET_SKIP; 3130 } 3131 3132 if (ssl->handshake->new_session_tickets_count == 0) { 3133 MBEDTLS_SSL_DEBUG_MSG(2, ("NewSessionTicket: all tickets have " 3134 "been sent.")); 3135 return SSL_NEW_SESSION_TICKET_SKIP; 3136 } 3137 3138 return SSL_NEW_SESSION_TICKET_WRITE; 3139} 3140 3141#if defined(MBEDTLS_SSL_SESSION_TICKETS) 3142MBEDTLS_CHECK_RETURN_CRITICAL 3143static int ssl_tls13_prepare_new_session_ticket(mbedtls_ssl_context *ssl, 3144 unsigned char *ticket_nonce, 3145 size_t ticket_nonce_size) 3146{ 3147 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 3148 mbedtls_ssl_session *session = ssl->session; 3149 mbedtls_ssl_ciphersuite_t *ciphersuite_info; 3150 psa_algorithm_t psa_hash_alg; 3151 int hash_length; 3152 3153 MBEDTLS_SSL_DEBUG_MSG(2, ("=> prepare NewSessionTicket msg")); 3154 3155 /* Set ticket_flags depends on the advertised psk key exchange mode */ 3156 mbedtls_ssl_tls13_session_clear_ticket_flags( 3157 session, MBEDTLS_SSL_TLS1_3_TICKET_FLAGS_MASK); 3158#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) 3159 mbedtls_ssl_tls13_session_set_ticket_flags( 3160 session, ssl->handshake->tls13_kex_modes); 3161#endif 3162 3163#if defined(MBEDTLS_SSL_EARLY_DATA) 3164 if (ssl->conf->early_data_enabled == MBEDTLS_SSL_EARLY_DATA_ENABLED && 3165 ssl->conf->max_early_data_size > 0) { 3166 mbedtls_ssl_tls13_session_set_ticket_flags( 3167 session, MBEDTLS_SSL_TLS1_3_TICKET_ALLOW_EARLY_DATA); 3168 session->max_early_data_size = ssl->conf->max_early_data_size; 3169 } 3170#endif /* MBEDTLS_SSL_EARLY_DATA */ 3171 3172 MBEDTLS_SSL_PRINT_TICKET_FLAGS(4, session->ticket_flags); 3173 3174#if defined(MBEDTLS_SSL_EARLY_DATA) && defined(MBEDTLS_SSL_ALPN) 3175 if (session->ticket_alpn == NULL) { 3176 ret = mbedtls_ssl_session_set_ticket_alpn(session, ssl->alpn_chosen); 3177 if (ret != 0) { 3178 return ret; 3179 } 3180 } 3181#endif 3182 3183 /* Generate ticket_age_add */ 3184 if ((ret = ssl->conf->f_rng(ssl->conf->p_rng, 3185 (unsigned char *) &session->ticket_age_add, 3186 sizeof(session->ticket_age_add)) != 0)) { 3187 MBEDTLS_SSL_DEBUG_RET(1, "generate_ticket_age_add", ret); 3188 return ret; 3189 } 3190 MBEDTLS_SSL_DEBUG_MSG(3, ("ticket_age_add: %u", 3191 (unsigned int) session->ticket_age_add)); 3192 3193 /* Generate ticket_nonce */ 3194 ret = ssl->conf->f_rng(ssl->conf->p_rng, ticket_nonce, ticket_nonce_size); 3195 if (ret != 0) { 3196 MBEDTLS_SSL_DEBUG_RET(1, "generate_ticket_nonce", ret); 3197 return ret; 3198 } 3199 MBEDTLS_SSL_DEBUG_BUF(3, "ticket_nonce:", 3200 ticket_nonce, ticket_nonce_size); 3201 3202 ciphersuite_info = 3203 (mbedtls_ssl_ciphersuite_t *) ssl->handshake->ciphersuite_info; 3204 psa_hash_alg = mbedtls_md_psa_alg_from_type((mbedtls_md_type_t) ciphersuite_info->mac); 3205 hash_length = PSA_HASH_LENGTH(psa_hash_alg); 3206 if (hash_length == -1 || 3207 (size_t) hash_length > sizeof(session->resumption_key)) { 3208 return MBEDTLS_ERR_SSL_INTERNAL_ERROR; 3209 } 3210 3211 /* In this code the psk key length equals the length of the hash */ 3212 session->resumption_key_len = hash_length; 3213 session->ciphersuite = ciphersuite_info->id; 3214 3215 /* Compute resumption key 3216 * 3217 * HKDF-Expand-Label( resumption_master_secret, 3218 * "resumption", ticket_nonce, Hash.length ) 3219 */ 3220 ret = mbedtls_ssl_tls13_hkdf_expand_label( 3221 psa_hash_alg, 3222 session->app_secrets.resumption_master_secret, 3223 hash_length, 3224 MBEDTLS_SSL_TLS1_3_LBL_WITH_LEN(resumption), 3225 ticket_nonce, 3226 ticket_nonce_size, 3227 session->resumption_key, 3228 hash_length); 3229 3230 if (ret != 0) { 3231 MBEDTLS_SSL_DEBUG_RET(2, 3232 "Creating the ticket-resumed PSK failed", 3233 ret); 3234 return ret; 3235 } 3236 MBEDTLS_SSL_DEBUG_BUF(3, "Ticket-resumed PSK", 3237 session->resumption_key, 3238 session->resumption_key_len); 3239 3240 MBEDTLS_SSL_DEBUG_BUF(3, "resumption_master_secret", 3241 session->app_secrets.resumption_master_secret, 3242 hash_length); 3243 3244 return 0; 3245} 3246 3247/* This function creates a NewSessionTicket message in the following format: 3248 * 3249 * struct { 3250 * uint32 ticket_lifetime; 3251 * uint32 ticket_age_add; 3252 * opaque ticket_nonce<0..255>; 3253 * opaque ticket<1..2^16-1>; 3254 * Extension extensions<0..2^16-2>; 3255 * } NewSessionTicket; 3256 * 3257 * The ticket inside the NewSessionTicket message is an encrypted container 3258 * carrying the necessary information so that the server is later able to 3259 * re-start the communication. 3260 * 3261 * The following fields are placed inside the ticket by the 3262 * f_ticket_write() function: 3263 * 3264 * - creation time (ticket_creation_time) 3265 * - flags (ticket_flags) 3266 * - age add (ticket_age_add) 3267 * - key (resumption_key) 3268 * - key length (resumption_key_len) 3269 * - ciphersuite (ciphersuite) 3270 * - max_early_data_size (max_early_data_size) 3271 */ 3272MBEDTLS_CHECK_RETURN_CRITICAL 3273static int ssl_tls13_write_new_session_ticket_body(mbedtls_ssl_context *ssl, 3274 unsigned char *buf, 3275 unsigned char *end, 3276 size_t *out_len, 3277 unsigned char *ticket_nonce, 3278 size_t ticket_nonce_size) 3279{ 3280 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 3281 unsigned char *p = buf; 3282 mbedtls_ssl_session *session = ssl->session; 3283 size_t ticket_len; 3284 uint32_t ticket_lifetime; 3285 unsigned char *p_extensions_len; 3286 3287 *out_len = 0; 3288 MBEDTLS_SSL_DEBUG_MSG(2, ("=> write NewSessionTicket msg")); 3289 3290 /* 3291 * ticket_lifetime 4 bytes 3292 * ticket_age_add 4 bytes 3293 * ticket_nonce 1 + ticket_nonce_size bytes 3294 * ticket >=2 bytes 3295 */ 3296 MBEDTLS_SSL_CHK_BUF_PTR(p, end, 4 + 4 + 1 + ticket_nonce_size + 2); 3297 3298 /* Generate ticket and ticket_lifetime */ 3299#if defined(MBEDTLS_HAVE_TIME) 3300 session->ticket_creation_time = mbedtls_ms_time(); 3301#endif 3302 ret = ssl->conf->f_ticket_write(ssl->conf->p_ticket, 3303 session, 3304 p + 9 + ticket_nonce_size + 2, 3305 end, 3306 &ticket_len, 3307 &ticket_lifetime); 3308 if (ret != 0) { 3309 MBEDTLS_SSL_DEBUG_RET(1, "write_ticket", ret); 3310 return ret; 3311 } 3312 3313 /* RFC 8446 section 4.6.1 3314 * 3315 * ticket_lifetime: Indicates the lifetime in seconds as a 32-bit 3316 * unsigned integer in network byte order from the time of ticket 3317 * issuance. Servers MUST NOT use any value greater than 3318 * 604800 seconds (7 days) ... 3319 */ 3320 if (ticket_lifetime > MBEDTLS_SSL_TLS1_3_MAX_ALLOWED_TICKET_LIFETIME) { 3321 MBEDTLS_SSL_DEBUG_MSG( 3322 1, ("Ticket lifetime (%u) is greater than 7 days.", 3323 (unsigned int) ticket_lifetime)); 3324 return MBEDTLS_ERR_SSL_BAD_INPUT_DATA; 3325 } 3326 3327 MBEDTLS_PUT_UINT32_BE(ticket_lifetime, p, 0); 3328 MBEDTLS_SSL_DEBUG_MSG(3, ("ticket_lifetime: %u", 3329 (unsigned int) ticket_lifetime)); 3330 3331 /* Write ticket_age_add */ 3332 MBEDTLS_PUT_UINT32_BE(session->ticket_age_add, p, 4); 3333 MBEDTLS_SSL_DEBUG_MSG(3, ("ticket_age_add: %u", 3334 (unsigned int) session->ticket_age_add)); 3335 3336 /* Write ticket_nonce */ 3337 p[8] = (unsigned char) ticket_nonce_size; 3338 if (ticket_nonce_size > 0) { 3339 memcpy(p + 9, ticket_nonce, ticket_nonce_size); 3340 } 3341 p += 9 + ticket_nonce_size; 3342 3343 /* Write ticket */ 3344 MBEDTLS_PUT_UINT16_BE(ticket_len, p, 0); 3345 p += 2; 3346 MBEDTLS_SSL_DEBUG_BUF(4, "ticket", p, ticket_len); 3347 p += ticket_len; 3348 3349 /* Ticket Extensions 3350 * 3351 * Extension extensions<0..2^16-2>; 3352 */ 3353 ssl->handshake->sent_extensions = MBEDTLS_SSL_EXT_MASK_NONE; 3354 3355 MBEDTLS_SSL_CHK_BUF_PTR(p, end, 2); 3356 p_extensions_len = p; 3357 p += 2; 3358 3359#if defined(MBEDTLS_SSL_EARLY_DATA) 3360 if (mbedtls_ssl_tls13_session_ticket_allow_early_data(session)) { 3361 size_t output_len; 3362 3363 if ((ret = mbedtls_ssl_tls13_write_early_data_ext( 3364 ssl, 1, p, end, &output_len)) != 0) { 3365 MBEDTLS_SSL_DEBUG_RET( 3366 1, "mbedtls_ssl_tls13_write_early_data_ext", ret); 3367 return ret; 3368 } 3369 p += output_len; 3370 } else { 3371 MBEDTLS_SSL_DEBUG_MSG( 3372 4, ("early_data not allowed, " 3373 "skip early_data extension in NewSessionTicket")); 3374 } 3375 3376#endif /* MBEDTLS_SSL_EARLY_DATA */ 3377 3378 MBEDTLS_PUT_UINT16_BE(p - p_extensions_len - 2, p_extensions_len, 0); 3379 3380 *out_len = p - buf; 3381 MBEDTLS_SSL_DEBUG_BUF(4, "ticket", buf, *out_len); 3382 MBEDTLS_SSL_DEBUG_MSG(2, ("<= write new session ticket")); 3383 3384 MBEDTLS_SSL_PRINT_EXTS( 3385 3, MBEDTLS_SSL_HS_NEW_SESSION_TICKET, ssl->handshake->sent_extensions); 3386 3387 return 0; 3388} 3389 3390/* 3391 * Handler for MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET 3392 */ 3393static int ssl_tls13_write_new_session_ticket(mbedtls_ssl_context *ssl) 3394{ 3395 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 3396 3397 MBEDTLS_SSL_PROC_CHK_NEG(ssl_tls13_write_new_session_ticket_coordinate(ssl)); 3398 3399 if (ret == SSL_NEW_SESSION_TICKET_WRITE) { 3400 unsigned char ticket_nonce[MBEDTLS_SSL_TLS1_3_TICKET_NONCE_LENGTH]; 3401 unsigned char *buf; 3402 size_t buf_len, msg_len; 3403 3404 MBEDTLS_SSL_PROC_CHK(ssl_tls13_prepare_new_session_ticket( 3405 ssl, ticket_nonce, sizeof(ticket_nonce))); 3406 3407 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_start_handshake_msg( 3408 ssl, MBEDTLS_SSL_HS_NEW_SESSION_TICKET, 3409 &buf, &buf_len)); 3410 3411 MBEDTLS_SSL_PROC_CHK(ssl_tls13_write_new_session_ticket_body( 3412 ssl, buf, buf + buf_len, &msg_len, 3413 ticket_nonce, sizeof(ticket_nonce))); 3414 3415 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_finish_handshake_msg( 3416 ssl, buf_len, msg_len)); 3417 3418 /* Limit session tickets count to one when resumption connection. 3419 * 3420 * See document of mbedtls_ssl_conf_new_session_tickets. 3421 */ 3422 if (ssl->handshake->resume == 1) { 3423 ssl->handshake->new_session_tickets_count = 0; 3424 } else { 3425 ssl->handshake->new_session_tickets_count--; 3426 } 3427 3428 mbedtls_ssl_handshake_set_state( 3429 ssl, MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET_FLUSH); 3430 } else { 3431 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_HANDSHAKE_OVER); 3432 } 3433 3434cleanup: 3435 3436 return ret; 3437} 3438#endif /* MBEDTLS_SSL_SESSION_TICKETS */ 3439 3440/* 3441 * TLS 1.3 State Machine -- server side 3442 */ 3443int mbedtls_ssl_tls13_handshake_server_step(mbedtls_ssl_context *ssl) 3444{ 3445 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 3446 3447 if (ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER || ssl->handshake == NULL) { 3448 return MBEDTLS_ERR_SSL_BAD_INPUT_DATA; 3449 } 3450 3451 MBEDTLS_SSL_DEBUG_MSG(2, ("tls13 server state: %s(%d)", 3452 mbedtls_ssl_states_str((mbedtls_ssl_states) ssl->state), 3453 ssl->state)); 3454 3455 switch (ssl->state) { 3456 /* start state */ 3457 case MBEDTLS_SSL_HELLO_REQUEST: 3458 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_CLIENT_HELLO); 3459 ret = 0; 3460 break; 3461 3462 case MBEDTLS_SSL_CLIENT_HELLO: 3463 ret = ssl_tls13_process_client_hello(ssl); 3464 if (ret != 0) { 3465 MBEDTLS_SSL_DEBUG_RET(1, "ssl_tls13_process_client_hello", ret); 3466 } 3467 break; 3468 3469 case MBEDTLS_SSL_HELLO_RETRY_REQUEST: 3470 ret = ssl_tls13_write_hello_retry_request(ssl); 3471 if (ret != 0) { 3472 MBEDTLS_SSL_DEBUG_RET(1, "ssl_tls13_write_hello_retry_request", ret); 3473 return ret; 3474 } 3475 break; 3476 3477 case MBEDTLS_SSL_SERVER_HELLO: 3478 ret = ssl_tls13_write_server_hello(ssl); 3479 break; 3480 3481 case MBEDTLS_SSL_ENCRYPTED_EXTENSIONS: 3482 ret = ssl_tls13_write_encrypted_extensions(ssl); 3483 if (ret != 0) { 3484 MBEDTLS_SSL_DEBUG_RET(1, "ssl_tls13_write_encrypted_extensions", ret); 3485 return ret; 3486 } 3487 break; 3488 3489#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED) 3490 case MBEDTLS_SSL_CERTIFICATE_REQUEST: 3491 ret = ssl_tls13_write_certificate_request(ssl); 3492 break; 3493 3494 case MBEDTLS_SSL_SERVER_CERTIFICATE: 3495 ret = ssl_tls13_write_server_certificate(ssl); 3496 break; 3497 3498 case MBEDTLS_SSL_CERTIFICATE_VERIFY: 3499 ret = ssl_tls13_write_certificate_verify(ssl); 3500 break; 3501#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */ 3502 3503 /* 3504 * Injection of dummy-CCS's for middlebox compatibility 3505 */ 3506#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE) 3507 case MBEDTLS_SSL_SERVER_CCS_AFTER_HELLO_RETRY_REQUEST: 3508 ret = mbedtls_ssl_tls13_write_change_cipher_spec(ssl); 3509 if (ret == 0) { 3510 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_CLIENT_HELLO); 3511 } 3512 break; 3513 3514 case MBEDTLS_SSL_SERVER_CCS_AFTER_SERVER_HELLO: 3515 ret = mbedtls_ssl_tls13_write_change_cipher_spec(ssl); 3516 if (ret != 0) { 3517 break; 3518 } 3519 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_ENCRYPTED_EXTENSIONS); 3520 break; 3521#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */ 3522 3523 case MBEDTLS_SSL_SERVER_FINISHED: 3524 ret = ssl_tls13_write_server_finished(ssl); 3525 break; 3526 3527#if defined(MBEDTLS_SSL_EARLY_DATA) 3528 case MBEDTLS_SSL_END_OF_EARLY_DATA: 3529 ret = ssl_tls13_process_end_of_early_data(ssl); 3530 break; 3531#endif /* MBEDTLS_SSL_EARLY_DATA */ 3532 3533 case MBEDTLS_SSL_CLIENT_FINISHED: 3534 ret = ssl_tls13_process_client_finished(ssl); 3535 break; 3536 3537 case MBEDTLS_SSL_HANDSHAKE_WRAPUP: 3538 ret = ssl_tls13_handshake_wrapup(ssl); 3539 break; 3540 3541#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED) 3542 case MBEDTLS_SSL_CLIENT_CERTIFICATE: 3543 ret = mbedtls_ssl_tls13_process_certificate(ssl); 3544 if (ret == 0) { 3545 if (ssl->session_negotiate->peer_cert != NULL) { 3546 mbedtls_ssl_handshake_set_state( 3547 ssl, MBEDTLS_SSL_CLIENT_CERTIFICATE_VERIFY); 3548 } else { 3549 MBEDTLS_SSL_DEBUG_MSG(2, ("skip parse certificate verify")); 3550 mbedtls_ssl_handshake_set_state( 3551 ssl, MBEDTLS_SSL_CLIENT_FINISHED); 3552 } 3553 } 3554 break; 3555 3556 case MBEDTLS_SSL_CLIENT_CERTIFICATE_VERIFY: 3557 ret = mbedtls_ssl_tls13_process_certificate_verify(ssl); 3558 if (ret == 0) { 3559 mbedtls_ssl_handshake_set_state( 3560 ssl, MBEDTLS_SSL_CLIENT_FINISHED); 3561 } 3562 break; 3563#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */ 3564 3565#if defined(MBEDTLS_SSL_SESSION_TICKETS) 3566 case MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET: 3567 ret = ssl_tls13_write_new_session_ticket(ssl); 3568 if (ret != 0) { 3569 MBEDTLS_SSL_DEBUG_RET(1, 3570 "ssl_tls13_write_new_session_ticket ", 3571 ret); 3572 } 3573 break; 3574 case MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET_FLUSH: 3575 /* This state is necessary to do the flush of the New Session 3576 * Ticket message written in MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET 3577 * as part of ssl_prepare_handshake_step. 3578 */ 3579 ret = 0; 3580 3581 if (ssl->handshake->new_session_tickets_count == 0) { 3582 mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_HANDSHAKE_OVER); 3583 } else { 3584 mbedtls_ssl_handshake_set_state( 3585 ssl, MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET); 3586 } 3587 break; 3588 3589#endif /* MBEDTLS_SSL_SESSION_TICKETS */ 3590 3591 default: 3592 MBEDTLS_SSL_DEBUG_MSG(1, ("invalid state %d", ssl->state)); 3593 return MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE; 3594 } 3595 3596 return ret; 3597} 3598 3599#endif /* MBEDTLS_SSL_SRV_C && MBEDTLS_SSL_PROTO_TLS1_3 */ 3600