1 /* 2 * Copyright 2015-2019 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the OpenSSL license (the "License"). You may not use 5 * this file except in compliance with the License. You can obtain a copy 6 * in the file LICENSE in the source distribution or at 7 * https://www.openssl.org/source/license.html 8 */ 9 10 #include "internal/cryptlib.h" 11 #include <openssl/rand.h> 12 #include "../ssl_local.h" 13 #include "statem_local.h" 14 #include <assert.h> 15 16 /* 17 * This file implements the SSL/TLS/DTLS state machines. 18 * 19 * There are two primary state machines: 20 * 21 * 1) Message flow state machine 22 * 2) Handshake state machine 23 * 24 * The Message flow state machine controls the reading and sending of messages 25 * including handling of non-blocking IO events, flushing of the underlying 26 * write BIO, handling unexpected messages, etc. It is itself broken into two 27 * separate sub-state machines which control reading and writing respectively. 28 * 29 * The Handshake state machine keeps track of the current SSL/TLS handshake 30 * state. Transitions of the handshake state are the result of events that 31 * occur within the Message flow state machine. 32 * 33 * Overall it looks like this: 34 * 35 * --------------------------------------------- ------------------- 36 * | | | | 37 * | Message flow state machine | | | 38 * | | | | 39 * | -------------------- -------------------- | Transition | Handshake state | 40 * | | MSG_FLOW_READING | | MSG_FLOW_WRITING | | Event | machine | 41 * | | sub-state | | sub-state | |----------->| | 42 * | | machine for | | machine for | | | | 43 * | | reading messages | | writing messages | | | | 44 * | -------------------- -------------------- | | | 45 * | | | | 46 * --------------------------------------------- ------------------- 47 * 48 */ 49 50 /* Sub state machine return values */ 51 typedef enum { 52 /* Something bad happened or NBIO */ 53 SUB_STATE_ERROR, 54 /* Sub state finished go to the next sub state */ 55 SUB_STATE_FINISHED, 56 /* Sub state finished and handshake was completed */ 57 SUB_STATE_END_HANDSHAKE 58 } SUB_STATE_RETURN; 59 60 static int state_machine(SSL *s, int server); 61 static void init_read_state_machine(SSL *s); 62 static SUB_STATE_RETURN read_state_machine(SSL *s); 63 static void init_write_state_machine(SSL *s); 64 static SUB_STATE_RETURN write_state_machine(SSL *s); 65 66 OSSL_HANDSHAKE_STATE SSL_get_state(const SSL *ssl) 67 { 68 return ssl->statem.hand_state; 69 } 70 71 int SSL_in_init(const SSL *s) 72 { 73 return s->statem.in_init; 74 } 75 76 int SSL_is_init_finished(const SSL *s) 77 { 78 return !(s->statem.in_init) && (s->statem.hand_state == TLS_ST_OK); 79 } 80 81 int SSL_in_before(const SSL *s) 82 { 83 /* 84 * Historically being "in before" meant before anything had happened. In the 85 * current code though we remain in the "before" state for a while after we 86 * have started the handshake process (e.g. as a server waiting for the 87 * first message to arrive). There "in before" is taken to mean "in before" 88 * and not started any handshake process yet. 89 */ 90 return (s->statem.hand_state == TLS_ST_BEFORE) 91 && (s->statem.state == MSG_FLOW_UNINITED); 92 } 93 94 /* 95 * Clear the state machine state and reset back to MSG_FLOW_UNINITED 96 */ 97 void ossl_statem_clear(SSL *s) 98 { 99 s->statem.state = MSG_FLOW_UNINITED; 100 s->statem.hand_state = TLS_ST_BEFORE; 101 s->statem.in_init = 1; 102 s->statem.no_cert_verify = 0; 103 } 104 105 /* 106 * Set the state machine up ready for a renegotiation handshake 107 */ 108 void ossl_statem_set_renegotiate(SSL *s) 109 { 110 s->statem.in_init = 1; 111 s->statem.request_state = TLS_ST_SW_HELLO_REQ; 112 } 113 114 /* 115 * Put the state machine into an error state and send an alert if appropriate. 116 * This is a permanent error for the current connection. 117 */ 118 void ossl_statem_fatal(SSL *s, int al, int func, int reason, const char *file, 119 int line) 120 { 121 ERR_put_error(ERR_LIB_SSL, func, reason, file, line); 122 /* We shouldn't call SSLfatal() twice. Once is enough */ 123 if (s->statem.in_init && s->statem.state == MSG_FLOW_ERROR) 124 return; 125 s->statem.in_init = 1; 126 s->statem.state = MSG_FLOW_ERROR; 127 if (al != SSL_AD_NO_ALERT 128 && s->statem.enc_write_state != ENC_WRITE_STATE_INVALID) 129 ssl3_send_alert(s, SSL3_AL_FATAL, al); 130 } 131 132 /* 133 * This macro should only be called if we are already expecting to be in 134 * a fatal error state. We verify that we are, and set it if not (this would 135 * indicate a bug). 136 */ 137 #define check_fatal(s, f) \ 138 do { \ 139 if (!ossl_assert((s)->statem.in_init \ 140 && (s)->statem.state == MSG_FLOW_ERROR)) \ 141 SSLfatal(s, SSL_AD_INTERNAL_ERROR, (f), \ 142 SSL_R_MISSING_FATAL); \ 143 } while (0) 144 145 /* 146 * Discover whether the current connection is in the error state. 147 * 148 * Valid return values are: 149 * 1: Yes 150 * 0: No 151 */ 152 int ossl_statem_in_error(const SSL *s) 153 { 154 if (s->statem.state == MSG_FLOW_ERROR) 155 return 1; 156 157 return 0; 158 } 159 160 void ossl_statem_set_in_init(SSL *s, int init) 161 { 162 s->statem.in_init = init; 163 } 164 165 int ossl_statem_get_in_handshake(SSL *s) 166 { 167 return s->statem.in_handshake; 168 } 169 170 void ossl_statem_set_in_handshake(SSL *s, int inhand) 171 { 172 if (inhand) 173 s->statem.in_handshake++; 174 else 175 s->statem.in_handshake--; 176 } 177 178 /* Are we in a sensible state to skip over unreadable early data? */ 179 int ossl_statem_skip_early_data(SSL *s) 180 { 181 if (s->ext.early_data != SSL_EARLY_DATA_REJECTED) 182 return 0; 183 184 if (!s->server 185 || s->statem.hand_state != TLS_ST_EARLY_DATA 186 || s->hello_retry_request == SSL_HRR_COMPLETE) 187 return 0; 188 189 return 1; 190 } 191 192 /* 193 * Called when we are in SSL_read*(), SSL_write*(), or SSL_accept() 194 * /SSL_connect()/SSL_do_handshake(). Used to test whether we are in an early 195 * data state and whether we should attempt to move the handshake on if so. 196 * |sending| is 1 if we are attempting to send data (SSL_write*()), 0 if we are 197 * attempting to read data (SSL_read*()), or -1 if we are in SSL_do_handshake() 198 * or similar. 199 */ 200 void ossl_statem_check_finish_init(SSL *s, int sending) 201 { 202 if (sending == -1) { 203 if (s->statem.hand_state == TLS_ST_PENDING_EARLY_DATA_END 204 || s->statem.hand_state == TLS_ST_EARLY_DATA) { 205 ossl_statem_set_in_init(s, 1); 206 if (s->early_data_state == SSL_EARLY_DATA_WRITE_RETRY) { 207 /* 208 * SSL_connect() or SSL_do_handshake() has been called directly. 209 * We don't allow any more writing of early data. 210 */ 211 s->early_data_state = SSL_EARLY_DATA_FINISHED_WRITING; 212 } 213 } 214 } else if (!s->server) { 215 if ((sending && (s->statem.hand_state == TLS_ST_PENDING_EARLY_DATA_END 216 || s->statem.hand_state == TLS_ST_EARLY_DATA) 217 && s->early_data_state != SSL_EARLY_DATA_WRITING) 218 || (!sending && s->statem.hand_state == TLS_ST_EARLY_DATA)) { 219 ossl_statem_set_in_init(s, 1); 220 /* 221 * SSL_write() has been called directly. We don't allow any more 222 * writing of early data. 223 */ 224 if (sending && s->early_data_state == SSL_EARLY_DATA_WRITE_RETRY) 225 s->early_data_state = SSL_EARLY_DATA_FINISHED_WRITING; 226 } 227 } else { 228 if (s->early_data_state == SSL_EARLY_DATA_FINISHED_READING 229 && s->statem.hand_state == TLS_ST_EARLY_DATA) 230 ossl_statem_set_in_init(s, 1); 231 } 232 } 233 234 void ossl_statem_set_hello_verify_done(SSL *s) 235 { 236 s->statem.state = MSG_FLOW_UNINITED; 237 s->statem.in_init = 1; 238 /* 239 * This will get reset (briefly) back to TLS_ST_BEFORE when we enter 240 * state_machine() because |state| is MSG_FLOW_UNINITED, but until then any 241 * calls to SSL_in_before() will return false. Also calls to 242 * SSL_state_string() and SSL_state_string_long() will return something 243 * sensible. 244 */ 245 s->statem.hand_state = TLS_ST_SR_CLNT_HELLO; 246 } 247 248 int ossl_statem_connect(SSL *s) 249 { 250 return state_machine(s, 0); 251 } 252 253 int ossl_statem_accept(SSL *s) 254 { 255 return state_machine(s, 1); 256 } 257 258 typedef void (*info_cb) (const SSL *, int, int); 259 260 static info_cb get_callback(SSL *s) 261 { 262 if (s->info_callback != NULL) 263 return s->info_callback; 264 else if (s->ctx->info_callback != NULL) 265 return s->ctx->info_callback; 266 267 return NULL; 268 } 269 270 /* 271 * The main message flow state machine. We start in the MSG_FLOW_UNINITED or 272 * MSG_FLOW_FINISHED state and finish in MSG_FLOW_FINISHED. Valid states and 273 * transitions are as follows: 274 * 275 * MSG_FLOW_UNINITED MSG_FLOW_FINISHED 276 * | | 277 * +-----------------------+ 278 * v 279 * MSG_FLOW_WRITING <---> MSG_FLOW_READING 280 * | 281 * V 282 * MSG_FLOW_FINISHED 283 * | 284 * V 285 * [SUCCESS] 286 * 287 * We may exit at any point due to an error or NBIO event. If an NBIO event 288 * occurs then we restart at the point we left off when we are recalled. 289 * MSG_FLOW_WRITING and MSG_FLOW_READING have sub-state machines associated with them. 290 * 291 * In addition to the above there is also the MSG_FLOW_ERROR state. We can move 292 * into that state at any point in the event that an irrecoverable error occurs. 293 * 294 * Valid return values are: 295 * 1: Success 296 * <=0: NBIO or error 297 */ 298 static int state_machine(SSL *s, int server) 299 { 300 BUF_MEM *buf = NULL; 301 void (*cb) (const SSL *ssl, int type, int val) = NULL; 302 OSSL_STATEM *st = &s->statem; 303 int ret = -1; 304 int ssret; 305 306 if (st->state == MSG_FLOW_ERROR) { 307 /* Shouldn't have been called if we're already in the error state */ 308 return -1; 309 } 310 311 ERR_clear_error(); 312 clear_sys_error(); 313 314 cb = get_callback(s); 315 316 st->in_handshake++; 317 if (!SSL_in_init(s) || SSL_in_before(s)) { 318 /* 319 * If we are stateless then we already called SSL_clear() - don't do 320 * it again and clear the STATELESS flag itself. 321 */ 322 if ((s->s3->flags & TLS1_FLAGS_STATELESS) == 0 && !SSL_clear(s)) 323 return -1; 324 } 325 #ifndef OPENSSL_NO_SCTP 326 if (SSL_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(s))) { 327 /* 328 * Notify SCTP BIO socket to enter handshake mode and prevent stream 329 * identifier other than 0. 330 */ 331 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE, 332 st->in_handshake, NULL); 333 } 334 #endif 335 336 /* Initialise state machine */ 337 if (st->state == MSG_FLOW_UNINITED 338 || st->state == MSG_FLOW_FINISHED) { 339 if (st->state == MSG_FLOW_UNINITED) { 340 st->hand_state = TLS_ST_BEFORE; 341 st->request_state = TLS_ST_BEFORE; 342 } 343 344 s->server = server; 345 if (cb != NULL) { 346 if (SSL_IS_FIRST_HANDSHAKE(s) || !SSL_IS_TLS13(s)) 347 cb(s, SSL_CB_HANDSHAKE_START, 1); 348 } 349 350 /* 351 * Fatal errors in this block don't send an alert because we have 352 * failed to even initialise properly. Sending an alert is probably 353 * doomed to failure. 354 */ 355 356 if (SSL_IS_DTLS(s)) { 357 if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00) && 358 (server || (s->version & 0xff00) != (DTLS1_BAD_VER & 0xff00))) { 359 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE, 360 ERR_R_INTERNAL_ERROR); 361 goto end; 362 } 363 } else { 364 if ((s->version >> 8) != SSL3_VERSION_MAJOR) { 365 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE, 366 ERR_R_INTERNAL_ERROR); 367 goto end; 368 } 369 } 370 371 if (!ssl_security(s, SSL_SECOP_VERSION, 0, s->version, NULL)) { 372 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE, 373 ERR_R_INTERNAL_ERROR); 374 goto end; 375 } 376 377 if (s->init_buf == NULL) { 378 if ((buf = BUF_MEM_new()) == NULL) { 379 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE, 380 ERR_R_INTERNAL_ERROR); 381 goto end; 382 } 383 if (!BUF_MEM_grow(buf, SSL3_RT_MAX_PLAIN_LENGTH)) { 384 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE, 385 ERR_R_INTERNAL_ERROR); 386 goto end; 387 } 388 s->init_buf = buf; 389 buf = NULL; 390 } 391 392 if (!ssl3_setup_buffers(s)) { 393 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE, 394 ERR_R_INTERNAL_ERROR); 395 goto end; 396 } 397 s->init_num = 0; 398 399 /* 400 * Should have been reset by tls_process_finished, too. 401 */ 402 s->s3->change_cipher_spec = 0; 403 404 /* 405 * Ok, we now need to push on a buffering BIO ...but not with 406 * SCTP 407 */ 408 #ifndef OPENSSL_NO_SCTP 409 if (!SSL_IS_DTLS(s) || !BIO_dgram_is_sctp(SSL_get_wbio(s))) 410 #endif 411 if (!ssl_init_wbio_buffer(s)) { 412 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE, 413 ERR_R_INTERNAL_ERROR); 414 goto end; 415 } 416 417 if ((SSL_in_before(s)) 418 || s->renegotiate) { 419 if (!tls_setup_handshake(s)) { 420 /* SSLfatal() already called */ 421 goto end; 422 } 423 424 if (SSL_IS_FIRST_HANDSHAKE(s)) 425 st->read_state_first_init = 1; 426 } 427 428 st->state = MSG_FLOW_WRITING; 429 init_write_state_machine(s); 430 } 431 432 while (st->state != MSG_FLOW_FINISHED) { 433 if (st->state == MSG_FLOW_READING) { 434 ssret = read_state_machine(s); 435 if (ssret == SUB_STATE_FINISHED) { 436 st->state = MSG_FLOW_WRITING; 437 init_write_state_machine(s); 438 } else { 439 /* NBIO or error */ 440 goto end; 441 } 442 } else if (st->state == MSG_FLOW_WRITING) { 443 ssret = write_state_machine(s); 444 if (ssret == SUB_STATE_FINISHED) { 445 st->state = MSG_FLOW_READING; 446 init_read_state_machine(s); 447 } else if (ssret == SUB_STATE_END_HANDSHAKE) { 448 st->state = MSG_FLOW_FINISHED; 449 } else { 450 /* NBIO or error */ 451 goto end; 452 } 453 } else { 454 /* Error */ 455 check_fatal(s, SSL_F_STATE_MACHINE); 456 SSLerr(SSL_F_STATE_MACHINE, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); 457 goto end; 458 } 459 } 460 461 ret = 1; 462 463 end: 464 st->in_handshake--; 465 466 #ifndef OPENSSL_NO_SCTP 467 if (SSL_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(s))) { 468 /* 469 * Notify SCTP BIO socket to leave handshake mode and allow stream 470 * identifier other than 0. 471 */ 472 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE, 473 st->in_handshake, NULL); 474 } 475 #endif 476 477 BUF_MEM_free(buf); 478 if (cb != NULL) { 479 if (server) 480 cb(s, SSL_CB_ACCEPT_EXIT, ret); 481 else 482 cb(s, SSL_CB_CONNECT_EXIT, ret); 483 } 484 return ret; 485 } 486 487 /* 488 * Initialise the MSG_FLOW_READING sub-state machine 489 */ 490 static void init_read_state_machine(SSL *s) 491 { 492 OSSL_STATEM *st = &s->statem; 493 494 st->read_state = READ_STATE_HEADER; 495 } 496 497 static int grow_init_buf(SSL *s, size_t size) { 498 499 size_t msg_offset = (char *)s->init_msg - s->init_buf->data; 500 501 if (!BUF_MEM_grow_clean(s->init_buf, (int)size)) 502 return 0; 503 504 if (size < msg_offset) 505 return 0; 506 507 s->init_msg = s->init_buf->data + msg_offset; 508 509 return 1; 510 } 511 512 /* 513 * This function implements the sub-state machine when the message flow is in 514 * MSG_FLOW_READING. The valid sub-states and transitions are: 515 * 516 * READ_STATE_HEADER <--+<-------------+ 517 * | | | 518 * v | | 519 * READ_STATE_BODY -----+-->READ_STATE_POST_PROCESS 520 * | | 521 * +----------------------------+ 522 * v 523 * [SUB_STATE_FINISHED] 524 * 525 * READ_STATE_HEADER has the responsibility for reading in the message header 526 * and transitioning the state of the handshake state machine. 527 * 528 * READ_STATE_BODY reads in the rest of the message and then subsequently 529 * processes it. 530 * 531 * READ_STATE_POST_PROCESS is an optional step that may occur if some post 532 * processing activity performed on the message may block. 533 * 534 * Any of the above states could result in an NBIO event occurring in which case 535 * control returns to the calling application. When this function is recalled we 536 * will resume in the same state where we left off. 537 */ 538 static SUB_STATE_RETURN read_state_machine(SSL *s) 539 { 540 OSSL_STATEM *st = &s->statem; 541 int ret, mt; 542 size_t len = 0; 543 int (*transition) (SSL *s, int mt); 544 PACKET pkt; 545 MSG_PROCESS_RETURN(*process_message) (SSL *s, PACKET *pkt); 546 WORK_STATE(*post_process_message) (SSL *s, WORK_STATE wst); 547 size_t (*max_message_size) (SSL *s); 548 void (*cb) (const SSL *ssl, int type, int val) = NULL; 549 550 cb = get_callback(s); 551 552 if (s->server) { 553 transition = ossl_statem_server_read_transition; 554 process_message = ossl_statem_server_process_message; 555 max_message_size = ossl_statem_server_max_message_size; 556 post_process_message = ossl_statem_server_post_process_message; 557 } else { 558 transition = ossl_statem_client_read_transition; 559 process_message = ossl_statem_client_process_message; 560 max_message_size = ossl_statem_client_max_message_size; 561 post_process_message = ossl_statem_client_post_process_message; 562 } 563 564 if (st->read_state_first_init) { 565 s->first_packet = 1; 566 st->read_state_first_init = 0; 567 } 568 569 while (1) { 570 switch (st->read_state) { 571 case READ_STATE_HEADER: 572 /* Get the state the peer wants to move to */ 573 if (SSL_IS_DTLS(s)) { 574 /* 575 * In DTLS we get the whole message in one go - header and body 576 */ 577 ret = dtls_get_message(s, &mt, &len); 578 } else { 579 ret = tls_get_message_header(s, &mt); 580 } 581 582 if (ret == 0) { 583 /* Could be non-blocking IO */ 584 return SUB_STATE_ERROR; 585 } 586 587 if (cb != NULL) { 588 /* Notify callback of an impending state change */ 589 if (s->server) 590 cb(s, SSL_CB_ACCEPT_LOOP, 1); 591 else 592 cb(s, SSL_CB_CONNECT_LOOP, 1); 593 } 594 /* 595 * Validate that we are allowed to move to the new state and move 596 * to that state if so 597 */ 598 if (!transition(s, mt)) 599 return SUB_STATE_ERROR; 600 601 if (s->s3->tmp.message_size > max_message_size(s)) { 602 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_READ_STATE_MACHINE, 603 SSL_R_EXCESSIVE_MESSAGE_SIZE); 604 return SUB_STATE_ERROR; 605 } 606 607 /* dtls_get_message already did this */ 608 if (!SSL_IS_DTLS(s) 609 && s->s3->tmp.message_size > 0 610 && !grow_init_buf(s, s->s3->tmp.message_size 611 + SSL3_HM_HEADER_LENGTH)) { 612 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_READ_STATE_MACHINE, 613 ERR_R_BUF_LIB); 614 return SUB_STATE_ERROR; 615 } 616 617 st->read_state = READ_STATE_BODY; 618 /* Fall through */ 619 620 case READ_STATE_BODY: 621 if (!SSL_IS_DTLS(s)) { 622 /* We already got this above for DTLS */ 623 ret = tls_get_message_body(s, &len); 624 if (ret == 0) { 625 /* Could be non-blocking IO */ 626 return SUB_STATE_ERROR; 627 } 628 } 629 630 s->first_packet = 0; 631 if (!PACKET_buf_init(&pkt, s->init_msg, len)) { 632 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_READ_STATE_MACHINE, 633 ERR_R_INTERNAL_ERROR); 634 return SUB_STATE_ERROR; 635 } 636 ret = process_message(s, &pkt); 637 638 /* Discard the packet data */ 639 s->init_num = 0; 640 641 switch (ret) { 642 case MSG_PROCESS_ERROR: 643 check_fatal(s, SSL_F_READ_STATE_MACHINE); 644 return SUB_STATE_ERROR; 645 646 case MSG_PROCESS_FINISHED_READING: 647 if (SSL_IS_DTLS(s)) { 648 dtls1_stop_timer(s); 649 } 650 return SUB_STATE_FINISHED; 651 652 case MSG_PROCESS_CONTINUE_PROCESSING: 653 st->read_state = READ_STATE_POST_PROCESS; 654 st->read_state_work = WORK_MORE_A; 655 break; 656 657 default: 658 st->read_state = READ_STATE_HEADER; 659 break; 660 } 661 break; 662 663 case READ_STATE_POST_PROCESS: 664 st->read_state_work = post_process_message(s, st->read_state_work); 665 switch (st->read_state_work) { 666 case WORK_ERROR: 667 check_fatal(s, SSL_F_READ_STATE_MACHINE); 668 /* Fall through */ 669 case WORK_MORE_A: 670 case WORK_MORE_B: 671 case WORK_MORE_C: 672 return SUB_STATE_ERROR; 673 674 case WORK_FINISHED_CONTINUE: 675 st->read_state = READ_STATE_HEADER; 676 break; 677 678 case WORK_FINISHED_STOP: 679 if (SSL_IS_DTLS(s)) { 680 dtls1_stop_timer(s); 681 } 682 return SUB_STATE_FINISHED; 683 } 684 break; 685 686 default: 687 /* Shouldn't happen */ 688 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_READ_STATE_MACHINE, 689 ERR_R_INTERNAL_ERROR); 690 return SUB_STATE_ERROR; 691 } 692 } 693 } 694 695 /* 696 * Send a previously constructed message to the peer. 697 */ 698 static int statem_do_write(SSL *s) 699 { 700 OSSL_STATEM *st = &s->statem; 701 702 if (st->hand_state == TLS_ST_CW_CHANGE 703 || st->hand_state == TLS_ST_SW_CHANGE) { 704 if (SSL_IS_DTLS(s)) 705 return dtls1_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC); 706 else 707 return ssl3_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC); 708 } else { 709 return ssl_do_write(s); 710 } 711 } 712 713 /* 714 * Initialise the MSG_FLOW_WRITING sub-state machine 715 */ 716 static void init_write_state_machine(SSL *s) 717 { 718 OSSL_STATEM *st = &s->statem; 719 720 st->write_state = WRITE_STATE_TRANSITION; 721 } 722 723 /* 724 * This function implements the sub-state machine when the message flow is in 725 * MSG_FLOW_WRITING. The valid sub-states and transitions are: 726 * 727 * +-> WRITE_STATE_TRANSITION ------> [SUB_STATE_FINISHED] 728 * | | 729 * | v 730 * | WRITE_STATE_PRE_WORK -----> [SUB_STATE_END_HANDSHAKE] 731 * | | 732 * | v 733 * | WRITE_STATE_SEND 734 * | | 735 * | v 736 * | WRITE_STATE_POST_WORK 737 * | | 738 * +-------------+ 739 * 740 * WRITE_STATE_TRANSITION transitions the state of the handshake state machine 741 742 * WRITE_STATE_PRE_WORK performs any work necessary to prepare the later 743 * sending of the message. This could result in an NBIO event occurring in 744 * which case control returns to the calling application. When this function 745 * is recalled we will resume in the same state where we left off. 746 * 747 * WRITE_STATE_SEND sends the message and performs any work to be done after 748 * sending. 749 * 750 * WRITE_STATE_POST_WORK performs any work necessary after the sending of the 751 * message has been completed. As for WRITE_STATE_PRE_WORK this could also 752 * result in an NBIO event. 753 */ 754 static SUB_STATE_RETURN write_state_machine(SSL *s) 755 { 756 OSSL_STATEM *st = &s->statem; 757 int ret; 758 WRITE_TRAN(*transition) (SSL *s); 759 WORK_STATE(*pre_work) (SSL *s, WORK_STATE wst); 760 WORK_STATE(*post_work) (SSL *s, WORK_STATE wst); 761 int (*get_construct_message_f) (SSL *s, WPACKET *pkt, 762 int (**confunc) (SSL *s, WPACKET *pkt), 763 int *mt); 764 void (*cb) (const SSL *ssl, int type, int val) = NULL; 765 int (*confunc) (SSL *s, WPACKET *pkt); 766 int mt; 767 WPACKET pkt; 768 769 cb = get_callback(s); 770 771 if (s->server) { 772 transition = ossl_statem_server_write_transition; 773 pre_work = ossl_statem_server_pre_work; 774 post_work = ossl_statem_server_post_work; 775 get_construct_message_f = ossl_statem_server_construct_message; 776 } else { 777 transition = ossl_statem_client_write_transition; 778 pre_work = ossl_statem_client_pre_work; 779 post_work = ossl_statem_client_post_work; 780 get_construct_message_f = ossl_statem_client_construct_message; 781 } 782 783 while (1) { 784 switch (st->write_state) { 785 case WRITE_STATE_TRANSITION: 786 if (cb != NULL) { 787 /* Notify callback of an impending state change */ 788 if (s->server) 789 cb(s, SSL_CB_ACCEPT_LOOP, 1); 790 else 791 cb(s, SSL_CB_CONNECT_LOOP, 1); 792 } 793 switch (transition(s)) { 794 case WRITE_TRAN_CONTINUE: 795 st->write_state = WRITE_STATE_PRE_WORK; 796 st->write_state_work = WORK_MORE_A; 797 break; 798 799 case WRITE_TRAN_FINISHED: 800 return SUB_STATE_FINISHED; 801 break; 802 803 case WRITE_TRAN_ERROR: 804 check_fatal(s, SSL_F_WRITE_STATE_MACHINE); 805 return SUB_STATE_ERROR; 806 } 807 break; 808 809 case WRITE_STATE_PRE_WORK: 810 switch (st->write_state_work = pre_work(s, st->write_state_work)) { 811 case WORK_ERROR: 812 check_fatal(s, SSL_F_WRITE_STATE_MACHINE); 813 /* Fall through */ 814 case WORK_MORE_A: 815 case WORK_MORE_B: 816 case WORK_MORE_C: 817 return SUB_STATE_ERROR; 818 819 case WORK_FINISHED_CONTINUE: 820 st->write_state = WRITE_STATE_SEND; 821 break; 822 823 case WORK_FINISHED_STOP: 824 return SUB_STATE_END_HANDSHAKE; 825 } 826 if (!get_construct_message_f(s, &pkt, &confunc, &mt)) { 827 /* SSLfatal() already called */ 828 return SUB_STATE_ERROR; 829 } 830 if (mt == SSL3_MT_DUMMY) { 831 /* Skip construction and sending. This isn't a "real" state */ 832 st->write_state = WRITE_STATE_POST_WORK; 833 st->write_state_work = WORK_MORE_A; 834 break; 835 } 836 if (!WPACKET_init(&pkt, s->init_buf) 837 || !ssl_set_handshake_header(s, &pkt, mt)) { 838 WPACKET_cleanup(&pkt); 839 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_WRITE_STATE_MACHINE, 840 ERR_R_INTERNAL_ERROR); 841 return SUB_STATE_ERROR; 842 } 843 if (confunc != NULL && !confunc(s, &pkt)) { 844 WPACKET_cleanup(&pkt); 845 check_fatal(s, SSL_F_WRITE_STATE_MACHINE); 846 return SUB_STATE_ERROR; 847 } 848 if (!ssl_close_construct_packet(s, &pkt, mt) 849 || !WPACKET_finish(&pkt)) { 850 WPACKET_cleanup(&pkt); 851 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_WRITE_STATE_MACHINE, 852 ERR_R_INTERNAL_ERROR); 853 return SUB_STATE_ERROR; 854 } 855 856 /* Fall through */ 857 858 case WRITE_STATE_SEND: 859 if (SSL_IS_DTLS(s) && st->use_timer) { 860 dtls1_start_timer(s); 861 } 862 ret = statem_do_write(s); 863 if (ret <= 0) { 864 return SUB_STATE_ERROR; 865 } 866 st->write_state = WRITE_STATE_POST_WORK; 867 st->write_state_work = WORK_MORE_A; 868 /* Fall through */ 869 870 case WRITE_STATE_POST_WORK: 871 switch (st->write_state_work = post_work(s, st->write_state_work)) { 872 case WORK_ERROR: 873 check_fatal(s, SSL_F_WRITE_STATE_MACHINE); 874 /* Fall through */ 875 case WORK_MORE_A: 876 case WORK_MORE_B: 877 case WORK_MORE_C: 878 return SUB_STATE_ERROR; 879 880 case WORK_FINISHED_CONTINUE: 881 st->write_state = WRITE_STATE_TRANSITION; 882 break; 883 884 case WORK_FINISHED_STOP: 885 return SUB_STATE_END_HANDSHAKE; 886 } 887 break; 888 889 default: 890 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_WRITE_STATE_MACHINE, 891 ERR_R_INTERNAL_ERROR); 892 return SUB_STATE_ERROR; 893 } 894 } 895 } 896 897 /* 898 * Flush the write BIO 899 */ 900 int statem_flush(SSL *s) 901 { 902 s->rwstate = SSL_WRITING; 903 if (BIO_flush(s->wbio) <= 0) { 904 return 0; 905 } 906 s->rwstate = SSL_NOTHING; 907 908 return 1; 909 } 910 911 /* 912 * Called by the record layer to determine whether application data is 913 * allowed to be received in the current handshake state or not. 914 * 915 * Return values are: 916 * 1: Yes (application data allowed) 917 * 0: No (application data not allowed) 918 */ 919 int ossl_statem_app_data_allowed(SSL *s) 920 { 921 OSSL_STATEM *st = &s->statem; 922 923 if (st->state == MSG_FLOW_UNINITED) 924 return 0; 925 926 if (!s->s3->in_read_app_data || (s->s3->total_renegotiations == 0)) 927 return 0; 928 929 if (s->server) { 930 /* 931 * If we're a server and we haven't got as far as writing our 932 * ServerHello yet then we allow app data 933 */ 934 if (st->hand_state == TLS_ST_BEFORE 935 || st->hand_state == TLS_ST_SR_CLNT_HELLO) 936 return 1; 937 } else { 938 /* 939 * If we're a client and we haven't read the ServerHello yet then we 940 * allow app data 941 */ 942 if (st->hand_state == TLS_ST_CW_CLNT_HELLO) 943 return 1; 944 } 945 946 return 0; 947 } 948 949 /* 950 * This function returns 1 if TLS exporter is ready to export keying 951 * material, or 0 if otherwise. 952 */ 953 int ossl_statem_export_allowed(SSL *s) 954 { 955 return s->s3->previous_server_finished_len != 0 956 && s->statem.hand_state != TLS_ST_SW_FINISHED; 957 } 958 959 /* 960 * Return 1 if early TLS exporter is ready to export keying material, 961 * or 0 if otherwise. 962 */ 963 int ossl_statem_export_early_allowed(SSL *s) 964 { 965 /* 966 * The early exporter secret is only present on the server if we 967 * have accepted early_data. It is present on the client as long 968 * as we have sent early_data. 969 */ 970 return s->ext.early_data == SSL_EARLY_DATA_ACCEPTED 971 || (!s->server && s->ext.early_data != SSL_EARLY_DATA_NOT_SENT); 972 } 973