1 /*
2 * Copyright 2015-2025 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (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/e_os.h"
11
12 #if defined(__TANDEM) && defined(_SPT_MODEL_)
13 #include <spthread.h>
14 #include <spt_extensions.h> /* timeval */
15 #endif
16
17 #include "internal/cryptlib.h"
18 #include "internal/ssl_unwrap.h"
19 #include <openssl/rand.h>
20 #include "../ssl_local.h"
21 #include "statem_local.h"
22 #include <assert.h>
23
24 /*
25 * This file implements the SSL/TLS/DTLS state machines.
26 *
27 * There are two primary state machines:
28 *
29 * 1) Message flow state machine
30 * 2) Handshake state machine
31 *
32 * The Message flow state machine controls the reading and sending of messages
33 * including handling of non-blocking IO events, flushing of the underlying
34 * write BIO, handling unexpected messages, etc. It is itself broken into two
35 * separate sub-state machines which control reading and writing respectively.
36 *
37 * The Handshake state machine keeps track of the current SSL/TLS handshake
38 * state. Transitions of the handshake state are the result of events that
39 * occur within the Message flow state machine.
40 *
41 * Overall it looks like this:
42 *
43 * --------------------------------------------- -------------------
44 * | | | |
45 * | Message flow state machine | | |
46 * | | | |
47 * | -------------------- -------------------- | Transition | Handshake state |
48 * | | MSG_FLOW_READING | | MSG_FLOW_WRITING | | Event | machine |
49 * | | sub-state | | sub-state | |----------->| |
50 * | | machine for | | machine for | | | |
51 * | | reading messages | | writing messages | | | |
52 * | -------------------- -------------------- | | |
53 * | | | |
54 * --------------------------------------------- -------------------
55 *
56 */
57
58 /* Sub state machine return values */
59 typedef enum {
60 /* Something bad happened or NBIO */
61 SUB_STATE_ERROR,
62 /* Sub state finished go to the next sub state */
63 SUB_STATE_FINISHED,
64 /* Sub state finished and handshake was completed */
65 SUB_STATE_END_HANDSHAKE
66 } SUB_STATE_RETURN;
67
68 static int state_machine(SSL_CONNECTION *s, int server);
69 static void init_read_state_machine(SSL_CONNECTION *s);
70 static SUB_STATE_RETURN read_state_machine(SSL_CONNECTION *s);
71 static void init_write_state_machine(SSL_CONNECTION *s);
72 static SUB_STATE_RETURN write_state_machine(SSL_CONNECTION *s);
73
SSL_get_state(const SSL * ssl)74 OSSL_HANDSHAKE_STATE SSL_get_state(const SSL *ssl)
75 {
76 const SSL_CONNECTION *sc = SSL_CONNECTION_FROM_CONST_SSL(ssl);
77
78 if (sc == NULL)
79 return TLS_ST_BEFORE;
80
81 return sc->statem.hand_state;
82 }
83
SSL_in_init(const SSL * s)84 int SSL_in_init(const SSL *s)
85 {
86 const SSL_CONNECTION *sc = SSL_CONNECTION_FROM_CONST_SSL(s);
87
88 if (sc == NULL)
89 return 0;
90
91 return sc->statem.in_init;
92 }
93
SSL_is_init_finished(const SSL * s)94 int SSL_is_init_finished(const SSL *s)
95 {
96 const SSL_CONNECTION *sc = SSL_CONNECTION_FROM_CONST_SSL(s);
97
98 if (sc == NULL)
99 return 0;
100
101 return !(sc->statem.in_init) && (sc->statem.hand_state == TLS_ST_OK);
102 }
103
SSL_in_before(const SSL * s)104 int SSL_in_before(const SSL *s)
105 {
106 const SSL_CONNECTION *sc = SSL_CONNECTION_FROM_CONST_SSL(s);
107
108 if (sc == NULL)
109 return 0;
110
111 /*
112 * Historically being "in before" meant before anything had happened. In the
113 * current code though we remain in the "before" state for a while after we
114 * have started the handshake process (e.g. as a server waiting for the
115 * first message to arrive). There "in before" is taken to mean "in before"
116 * and not started any handshake process yet.
117 */
118 return (sc->statem.hand_state == TLS_ST_BEFORE)
119 && (sc->statem.state == MSG_FLOW_UNINITED);
120 }
121
ossl_statem_get_state(SSL_CONNECTION * s)122 OSSL_HANDSHAKE_STATE ossl_statem_get_state(SSL_CONNECTION *s)
123 {
124 return s != NULL ? s->statem.hand_state : TLS_ST_BEFORE;
125 }
126
127 /*
128 * Clear the state machine state and reset back to MSG_FLOW_UNINITED
129 */
ossl_statem_clear(SSL_CONNECTION * s)130 void ossl_statem_clear(SSL_CONNECTION *s)
131 {
132 s->statem.state = MSG_FLOW_UNINITED;
133 s->statem.hand_state = TLS_ST_BEFORE;
134 ossl_statem_set_in_init(s, 1);
135 s->statem.no_cert_verify = 0;
136 }
137
138 /*
139 * Set the state machine up ready for a renegotiation handshake
140 */
ossl_statem_set_renegotiate(SSL_CONNECTION * s)141 void ossl_statem_set_renegotiate(SSL_CONNECTION *s)
142 {
143 ossl_statem_set_in_init(s, 1);
144 s->statem.request_state = TLS_ST_SW_HELLO_REQ;
145 }
146
ossl_statem_send_fatal(SSL_CONNECTION * s,int al)147 void ossl_statem_send_fatal(SSL_CONNECTION *s, int al)
148 {
149 /* We shouldn't call SSLfatal() twice. Once is enough */
150 if (s->statem.in_init && s->statem.state == MSG_FLOW_ERROR)
151 return;
152 ossl_statem_set_in_init(s, 1);
153 s->statem.state = MSG_FLOW_ERROR;
154 if (al != SSL_AD_NO_ALERT)
155 ssl3_send_alert(s, SSL3_AL_FATAL, al);
156 }
157
158 /*
159 * Error reporting building block that's used instead of ERR_set_error().
160 * In addition to what ERR_set_error() does, this puts the state machine
161 * into an error state and sends an alert if appropriate.
162 * This is a permanent error for the current connection.
163 */
ossl_statem_fatal(SSL_CONNECTION * s,int al,int reason,const char * fmt,...)164 void ossl_statem_fatal(SSL_CONNECTION *s, int al, int reason,
165 const char *fmt, ...)
166 {
167 va_list args;
168
169 va_start(args, fmt);
170 ERR_vset_error(ERR_LIB_SSL, reason, fmt, args);
171 va_end(args);
172
173 ossl_statem_send_fatal(s, al);
174 }
175
176 /*
177 * This macro should only be called if we are already expecting to be in
178 * a fatal error state. We verify that we are, and set it if not (this would
179 * indicate a bug).
180 */
181 #define check_fatal(s) \
182 do { \
183 if (!ossl_assert((s)->statem.in_init \
184 && (s)->statem.state == MSG_FLOW_ERROR)) \
185 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_R_MISSING_FATAL); \
186 } while (0)
187
188 /*
189 * Discover whether the current connection is in the error state.
190 *
191 * Valid return values are:
192 * 1: Yes
193 * 0: No
194 */
ossl_statem_in_error(const SSL_CONNECTION * s)195 int ossl_statem_in_error(const SSL_CONNECTION *s)
196 {
197 if (s->statem.state == MSG_FLOW_ERROR)
198 return 1;
199
200 return 0;
201 }
202
ossl_statem_set_in_init(SSL_CONNECTION * s,int init)203 void ossl_statem_set_in_init(SSL_CONNECTION *s, int init)
204 {
205 s->statem.in_init = init;
206 if (s->rlayer.rrlmethod != NULL && s->rlayer.rrlmethod->set_in_init != NULL)
207 s->rlayer.rrlmethod->set_in_init(s->rlayer.rrl, init);
208 }
209
ossl_statem_get_in_handshake(SSL_CONNECTION * s)210 int ossl_statem_get_in_handshake(SSL_CONNECTION *s)
211 {
212 return s->statem.in_handshake;
213 }
214
ossl_statem_set_in_handshake(SSL_CONNECTION * s,int inhand)215 void ossl_statem_set_in_handshake(SSL_CONNECTION *s, int inhand)
216 {
217 if (inhand)
218 s->statem.in_handshake++;
219 else
220 s->statem.in_handshake--;
221 }
222
223 /* Are we in a sensible state to skip over unreadable early data? */
ossl_statem_skip_early_data(SSL_CONNECTION * s)224 int ossl_statem_skip_early_data(SSL_CONNECTION *s)
225 {
226 if (s->ext.early_data != SSL_EARLY_DATA_REJECTED)
227 return 0;
228
229 if (!s->server
230 || s->statem.hand_state != TLS_ST_EARLY_DATA
231 || s->hello_retry_request == SSL_HRR_COMPLETE)
232 return 0;
233
234 return 1;
235 }
236
237 /*
238 * Called when we are in SSL_read*(), SSL_write*(), or SSL_accept()
239 * /SSL_connect()/SSL_do_handshake(). Used to test whether we are in an early
240 * data state and whether we should attempt to move the handshake on if so.
241 * |sending| is 1 if we are attempting to send data (SSL_write*()), 0 if we are
242 * attempting to read data (SSL_read*()), or -1 if we are in SSL_do_handshake()
243 * or similar.
244 */
ossl_statem_check_finish_init(SSL_CONNECTION * s,int sending)245 int ossl_statem_check_finish_init(SSL_CONNECTION *s, int sending)
246 {
247 if (sending == -1) {
248 if (s->statem.hand_state == TLS_ST_PENDING_EARLY_DATA_END
249 || s->statem.hand_state == TLS_ST_EARLY_DATA) {
250 ossl_statem_set_in_init(s, 1);
251 if (s->early_data_state == SSL_EARLY_DATA_WRITE_RETRY) {
252 /*
253 * SSL_connect() or SSL_do_handshake() has been called directly.
254 * We don't allow any more writing of early data.
255 */
256 s->early_data_state = SSL_EARLY_DATA_FINISHED_WRITING;
257 }
258 }
259 } else if (!s->server) {
260 if ((sending && (s->statem.hand_state == TLS_ST_PENDING_EARLY_DATA_END || s->statem.hand_state == TLS_ST_EARLY_DATA)
261 && s->early_data_state != SSL_EARLY_DATA_WRITING)
262 || (!sending && s->statem.hand_state == TLS_ST_EARLY_DATA)) {
263 ossl_statem_set_in_init(s, 1);
264 /*
265 * SSL_write() has been called directly. We don't allow any more
266 * writing of early data.
267 */
268 if (sending && s->early_data_state == SSL_EARLY_DATA_WRITE_RETRY)
269 s->early_data_state = SSL_EARLY_DATA_FINISHED_WRITING;
270 }
271 } else {
272 if (s->early_data_state == SSL_EARLY_DATA_FINISHED_READING
273 && s->statem.hand_state == TLS_ST_EARLY_DATA)
274 ossl_statem_set_in_init(s, 1);
275 }
276 return 1;
277 }
278
ossl_statem_set_hello_verify_done(SSL_CONNECTION * s)279 void ossl_statem_set_hello_verify_done(SSL_CONNECTION *s)
280 {
281 s->statem.state = MSG_FLOW_UNINITED;
282 ossl_statem_set_in_init(s, 1);
283 /*
284 * This will get reset (briefly) back to TLS_ST_BEFORE when we enter
285 * state_machine() because |state| is MSG_FLOW_UNINITED, but until then any
286 * calls to SSL_in_before() will return false. Also calls to
287 * SSL_state_string() and SSL_state_string_long() will return something
288 * sensible.
289 */
290 s->statem.hand_state = TLS_ST_SR_CLNT_HELLO;
291 }
292
ossl_statem_connect(SSL * s)293 int ossl_statem_connect(SSL *s)
294 {
295 SSL_CONNECTION *sc = SSL_CONNECTION_FROM_SSL(s);
296
297 if (sc == NULL)
298 return -1;
299
300 return state_machine(sc, 0);
301 }
302
ossl_statem_accept(SSL * s)303 int ossl_statem_accept(SSL *s)
304 {
305 SSL_CONNECTION *sc = SSL_CONNECTION_FROM_SSL(s);
306
307 if (sc == NULL)
308 return -1;
309
310 return state_machine(sc, 1);
311 }
312
313 typedef void (*info_cb)(const SSL *, int, int);
314
get_callback(SSL_CONNECTION * s)315 static info_cb get_callback(SSL_CONNECTION *s)
316 {
317 SSL_CTX *sctx = SSL_CONNECTION_GET_CTX(s);
318
319 if (s->info_callback != NULL)
320 return s->info_callback;
321 else if (sctx->info_callback != NULL)
322 return sctx->info_callback;
323
324 return NULL;
325 }
326
327 /*
328 * The main message flow state machine. We start in the MSG_FLOW_UNINITED or
329 * MSG_FLOW_FINISHED state and finish in MSG_FLOW_FINISHED. Valid states and
330 * transitions are as follows:
331 *
332 * MSG_FLOW_UNINITED MSG_FLOW_FINISHED
333 * | |
334 * +-----------------------+
335 * v
336 * MSG_FLOW_WRITING <---> MSG_FLOW_READING
337 * |
338 * V
339 * MSG_FLOW_FINISHED
340 * |
341 * V
342 * [SUCCESS]
343 *
344 * We may exit at any point due to an error or NBIO event. If an NBIO event
345 * occurs then we restart at the point we left off when we are recalled.
346 * MSG_FLOW_WRITING and MSG_FLOW_READING have sub-state machines associated with them.
347 *
348 * In addition to the above there is also the MSG_FLOW_ERROR state. We can move
349 * into that state at any point in the event that an irrecoverable error occurs.
350 *
351 * Valid return values are:
352 * 1: Success
353 * <=0: NBIO or error
354 */
state_machine(SSL_CONNECTION * s,int server)355 static int state_machine(SSL_CONNECTION *s, int server)
356 {
357 BUF_MEM *buf = NULL;
358 void (*cb)(const SSL *ssl, int type, int val) = NULL;
359 OSSL_STATEM *st = &s->statem;
360 int ret = -1;
361 int ssret;
362 SSL *ssl = SSL_CONNECTION_GET_SSL(s);
363 SSL *ussl = SSL_CONNECTION_GET_USER_SSL(s);
364
365 if (st->state == MSG_FLOW_ERROR) {
366 /* Shouldn't have been called if we're already in the error state */
367 return -1;
368 }
369
370 ERR_clear_error();
371 clear_sys_error();
372
373 cb = get_callback(s);
374
375 st->in_handshake++;
376 if (!SSL_in_init(ssl) || SSL_in_before(ssl)) {
377 /*
378 * If we are stateless then we already called SSL_clear() - don't do
379 * it again and clear the STATELESS flag itself.
380 */
381 if ((s->s3.flags & TLS1_FLAGS_STATELESS) == 0 && !SSL_clear(ssl))
382 return -1;
383 }
384 #ifndef OPENSSL_NO_SCTP
385 if (SSL_CONNECTION_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(ssl))) {
386 /*
387 * Notify SCTP BIO socket to enter handshake mode and prevent stream
388 * identifier other than 0.
389 */
390 BIO_ctrl(SSL_get_wbio(ssl), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
391 st->in_handshake, NULL);
392 }
393 #endif
394
395 /* Initialise state machine */
396 if (st->state == MSG_FLOW_UNINITED
397 || st->state == MSG_FLOW_FINISHED) {
398 if (st->state == MSG_FLOW_UNINITED) {
399 st->hand_state = TLS_ST_BEFORE;
400 st->request_state = TLS_ST_BEFORE;
401 }
402
403 s->server = server;
404 if (cb != NULL) {
405 if (SSL_IS_FIRST_HANDSHAKE(s) || !SSL_CONNECTION_IS_TLS13(s))
406 cb(ussl, SSL_CB_HANDSHAKE_START, 1);
407 }
408
409 /*
410 * Fatal errors in this block don't send an alert because we have
411 * failed to even initialise properly. Sending an alert is probably
412 * doomed to failure.
413 */
414
415 if (SSL_CONNECTION_IS_DTLS(s)) {
416 if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00) && (server || (s->version & 0xff00) != (DTLS1_BAD_VER & 0xff00))) {
417 SSLfatal(s, SSL_AD_NO_ALERT, ERR_R_INTERNAL_ERROR);
418 goto end;
419 }
420 } else {
421 if ((s->version >> 8) != SSL3_VERSION_MAJOR) {
422 SSLfatal(s, SSL_AD_NO_ALERT, ERR_R_INTERNAL_ERROR);
423 goto end;
424 }
425 }
426
427 if (!ssl_security(s, SSL_SECOP_VERSION, 0, s->version, NULL)) {
428 SSLfatal(s, SSL_AD_NO_ALERT, ERR_R_INTERNAL_ERROR);
429 goto end;
430 }
431
432 if (s->init_buf == NULL) {
433 if ((buf = BUF_MEM_new()) == NULL) {
434 SSLfatal(s, SSL_AD_NO_ALERT, ERR_R_INTERNAL_ERROR);
435 goto end;
436 }
437 if (!BUF_MEM_grow(buf, SSL3_RT_MAX_PLAIN_LENGTH)) {
438 SSLfatal(s, SSL_AD_NO_ALERT, ERR_R_INTERNAL_ERROR);
439 goto end;
440 }
441 s->init_buf = buf;
442 buf = NULL;
443 }
444
445 s->init_num = 0;
446
447 /*
448 * Should have been reset by tls_process_finished, too.
449 */
450 s->s3.change_cipher_spec = 0;
451
452 /*
453 * Ok, we now need to push on a buffering BIO ...but not with
454 * SCTP
455 */
456 #ifndef OPENSSL_NO_SCTP
457 if (!SSL_CONNECTION_IS_DTLS(s) || !BIO_dgram_is_sctp(SSL_get_wbio(ssl)))
458 #endif
459 if (!ssl_init_wbio_buffer(s)) {
460 SSLfatal(s, SSL_AD_NO_ALERT, ERR_R_INTERNAL_ERROR);
461 goto end;
462 }
463
464 if ((SSL_in_before(ssl))
465 || s->renegotiate) {
466 if (!tls_setup_handshake(s)) {
467 /* SSLfatal() already called */
468 goto end;
469 }
470
471 if (SSL_IS_FIRST_HANDSHAKE(s))
472 st->read_state_first_init = 1;
473 }
474
475 st->state = MSG_FLOW_WRITING;
476 init_write_state_machine(s);
477 }
478
479 while (st->state != MSG_FLOW_FINISHED) {
480 if (st->state == MSG_FLOW_READING) {
481 ssret = read_state_machine(s);
482 if (ssret == SUB_STATE_FINISHED) {
483 st->state = MSG_FLOW_WRITING;
484 init_write_state_machine(s);
485 } else {
486 /* NBIO or error */
487 goto end;
488 }
489 } else if (st->state == MSG_FLOW_WRITING) {
490 ssret = write_state_machine(s);
491 if (ssret == SUB_STATE_FINISHED) {
492 st->state = MSG_FLOW_READING;
493 init_read_state_machine(s);
494 } else if (ssret == SUB_STATE_END_HANDSHAKE) {
495 st->state = MSG_FLOW_FINISHED;
496 } else {
497 /* NBIO or error */
498 goto end;
499 }
500 } else {
501 /* Error */
502 check_fatal(s);
503 ERR_raise(ERR_LIB_SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
504 goto end;
505 }
506 }
507
508 ret = 1;
509
510 end:
511 st->in_handshake--;
512
513 #ifndef OPENSSL_NO_SCTP
514 if (SSL_CONNECTION_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(ssl))) {
515 /*
516 * Notify SCTP BIO socket to leave handshake mode and allow stream
517 * identifier other than 0.
518 */
519 BIO_ctrl(SSL_get_wbio(ssl), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
520 st->in_handshake, NULL);
521 }
522 #endif
523
524 BUF_MEM_free(buf);
525 if (cb != NULL) {
526 if (server)
527 cb(ussl, SSL_CB_ACCEPT_EXIT, ret);
528 else
529 cb(ussl, SSL_CB_CONNECT_EXIT, ret);
530 }
531 return ret;
532 }
533
534 /*
535 * Initialise the MSG_FLOW_READING sub-state machine
536 */
init_read_state_machine(SSL_CONNECTION * s)537 static void init_read_state_machine(SSL_CONNECTION *s)
538 {
539 OSSL_STATEM *st = &s->statem;
540
541 st->read_state = READ_STATE_HEADER;
542 }
543
grow_init_buf(SSL_CONNECTION * s,size_t size)544 static int grow_init_buf(SSL_CONNECTION *s, size_t size)
545 {
546
547 size_t msg_offset = (char *)s->init_msg - s->init_buf->data;
548
549 if (!BUF_MEM_grow_clean(s->init_buf, (int)size))
550 return 0;
551
552 if (size < msg_offset)
553 return 0;
554
555 s->init_msg = s->init_buf->data + msg_offset;
556
557 return 1;
558 }
559
560 /*
561 * This function implements the sub-state machine when the message flow is in
562 * MSG_FLOW_READING. The valid sub-states and transitions are:
563 *
564 * READ_STATE_HEADER <--+<-------------+
565 * | | |
566 * v | |
567 * READ_STATE_BODY -----+-->READ_STATE_POST_PROCESS
568 * | |
569 * +----------------------------+
570 * v
571 * [SUB_STATE_FINISHED]
572 *
573 * READ_STATE_HEADER has the responsibility for reading in the message header
574 * and transitioning the state of the handshake state machine.
575 *
576 * READ_STATE_BODY reads in the rest of the message and then subsequently
577 * processes it.
578 *
579 * READ_STATE_POST_PROCESS is an optional step that may occur if some post
580 * processing activity performed on the message may block.
581 *
582 * Any of the above states could result in an NBIO event occurring in which case
583 * control returns to the calling application. When this function is recalled we
584 * will resume in the same state where we left off.
585 */
read_state_machine(SSL_CONNECTION * s)586 static SUB_STATE_RETURN read_state_machine(SSL_CONNECTION *s)
587 {
588 OSSL_STATEM *st = &s->statem;
589 int ret, mt;
590 size_t len = 0;
591 int (*transition)(SSL_CONNECTION *s, int mt);
592 PACKET pkt;
593 MSG_PROCESS_RETURN (*process_message)(SSL_CONNECTION *s, PACKET *pkt);
594 WORK_STATE (*post_process_message)(SSL_CONNECTION *s, WORK_STATE wst);
595 size_t (*max_message_size)(SSL_CONNECTION *s);
596 void (*cb)(const SSL *ssl, int type, int val) = NULL;
597 SSL *ssl = SSL_CONNECTION_GET_USER_SSL(s);
598
599 cb = get_callback(s);
600
601 if (s->server) {
602 transition = ossl_statem_server_read_transition;
603 process_message = ossl_statem_server_process_message;
604 max_message_size = ossl_statem_server_max_message_size;
605 post_process_message = ossl_statem_server_post_process_message;
606 } else {
607 transition = ossl_statem_client_read_transition;
608 process_message = ossl_statem_client_process_message;
609 max_message_size = ossl_statem_client_max_message_size;
610 post_process_message = ossl_statem_client_post_process_message;
611 }
612
613 if (st->read_state_first_init) {
614 s->first_packet = 1;
615 st->read_state_first_init = 0;
616 }
617
618 while (1) {
619 switch (st->read_state) {
620 case READ_STATE_HEADER:
621 /* Get the state the peer wants to move to */
622 if (SSL_CONNECTION_IS_DTLS(s)) {
623 /*
624 * In DTLS we get the whole message in one go - header and body
625 */
626 ret = dtls_get_message(s, &mt);
627 } else {
628 ret = tls_get_message_header(s, &mt);
629 }
630
631 if (ret == 0) {
632 /* Could be non-blocking IO */
633 return SUB_STATE_ERROR;
634 }
635
636 if (cb != NULL) {
637 /* Notify callback of an impending state change */
638 if (s->server)
639 cb(ssl, SSL_CB_ACCEPT_LOOP, 1);
640 else
641 cb(ssl, SSL_CB_CONNECT_LOOP, 1);
642 }
643 /*
644 * Validate that we are allowed to move to the new state and move
645 * to that state if so
646 */
647 if (!transition(s, mt))
648 return SUB_STATE_ERROR;
649
650 if (s->s3.tmp.message_size > max_message_size(s)) {
651 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
652 SSL_R_EXCESSIVE_MESSAGE_SIZE);
653 return SUB_STATE_ERROR;
654 }
655
656 /* dtls_get_message already did this */
657 if (!SSL_CONNECTION_IS_DTLS(s)
658 && s->s3.tmp.message_size > 0
659 && !grow_init_buf(s, s->s3.tmp.message_size + SSL3_HM_HEADER_LENGTH)) {
660 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_BUF_LIB);
661 return SUB_STATE_ERROR;
662 }
663
664 st->read_state = READ_STATE_BODY;
665 /* Fall through */
666
667 case READ_STATE_BODY:
668 if (SSL_CONNECTION_IS_DTLS(s)) {
669 /*
670 * Actually we already have the body, but we give DTLS the
671 * opportunity to do any further processing.
672 */
673 ret = dtls_get_message_body(s, &len);
674 } else {
675 ret = tls_get_message_body(s, &len);
676 }
677 if (ret == 0) {
678 /* Could be non-blocking IO */
679 return SUB_STATE_ERROR;
680 }
681
682 s->first_packet = 0;
683 if (!PACKET_buf_init(&pkt, s->init_msg, len)) {
684 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
685 return SUB_STATE_ERROR;
686 }
687 ret = process_message(s, &pkt);
688
689 /* Discard the packet data */
690 s->init_num = 0;
691
692 switch (ret) {
693 case MSG_PROCESS_ERROR:
694 check_fatal(s);
695 return SUB_STATE_ERROR;
696
697 case MSG_PROCESS_FINISHED_READING:
698 if (SSL_CONNECTION_IS_DTLS(s)) {
699 dtls1_stop_timer(s);
700 }
701 return SUB_STATE_FINISHED;
702
703 case MSG_PROCESS_CONTINUE_PROCESSING:
704 st->read_state = READ_STATE_POST_PROCESS;
705 st->read_state_work = WORK_MORE_A;
706 break;
707
708 default:
709 st->read_state = READ_STATE_HEADER;
710 break;
711 }
712 break;
713
714 case READ_STATE_POST_PROCESS:
715 st->read_state_work = post_process_message(s, st->read_state_work);
716 switch (st->read_state_work) {
717 case WORK_ERROR:
718 check_fatal(s);
719 /* Fall through */
720 case WORK_MORE_A:
721 case WORK_MORE_B:
722 case WORK_MORE_C:
723 return SUB_STATE_ERROR;
724
725 case WORK_FINISHED_CONTINUE:
726 st->read_state = READ_STATE_HEADER;
727 break;
728
729 case WORK_FINISHED_SWAP:
730 case WORK_FINISHED_STOP:
731 if (SSL_CONNECTION_IS_DTLS(s)) {
732 dtls1_stop_timer(s);
733 }
734 return SUB_STATE_FINISHED;
735 }
736 break;
737
738 default:
739 /* Shouldn't happen */
740 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
741 return SUB_STATE_ERROR;
742 }
743 }
744 }
745
746 /*
747 * Send a previously constructed message to the peer.
748 */
statem_do_write(SSL_CONNECTION * s)749 static int statem_do_write(SSL_CONNECTION *s)
750 {
751 OSSL_STATEM *st = &s->statem;
752
753 if (st->hand_state == TLS_ST_CW_CHANGE
754 || st->hand_state == TLS_ST_SW_CHANGE) {
755 if (SSL_CONNECTION_IS_DTLS(s))
756 return dtls1_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC);
757 else
758 return ssl3_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC);
759 } else {
760 return ssl_do_write(s);
761 }
762 }
763
764 /*
765 * Initialise the MSG_FLOW_WRITING sub-state machine
766 */
init_write_state_machine(SSL_CONNECTION * s)767 static void init_write_state_machine(SSL_CONNECTION *s)
768 {
769 OSSL_STATEM *st = &s->statem;
770
771 st->write_state = WRITE_STATE_TRANSITION;
772 }
773
774 /*
775 * This function implements the sub-state machine when the message flow is in
776 * MSG_FLOW_WRITING. The valid sub-states and transitions are:
777 *
778 * +-> WRITE_STATE_TRANSITION ------> [SUB_STATE_FINISHED]
779 * | |
780 * | v
781 * | WRITE_STATE_PRE_WORK -----> [SUB_STATE_END_HANDSHAKE]
782 * | |
783 * | v
784 * | WRITE_STATE_SEND
785 * | |
786 * | v
787 * | WRITE_STATE_POST_WORK
788 * | |
789 * +-------------+
790 *
791 * WRITE_STATE_TRANSITION transitions the state of the handshake state machine
792
793 * WRITE_STATE_PRE_WORK performs any work necessary to prepare the later
794 * sending of the message. This could result in an NBIO event occurring in
795 * which case control returns to the calling application. When this function
796 * is recalled we will resume in the same state where we left off.
797 *
798 * WRITE_STATE_SEND sends the message and performs any work to be done after
799 * sending.
800 *
801 * WRITE_STATE_POST_WORK performs any work necessary after the sending of the
802 * message has been completed. As for WRITE_STATE_PRE_WORK this could also
803 * result in an NBIO event.
804 */
write_state_machine(SSL_CONNECTION * s)805 static SUB_STATE_RETURN write_state_machine(SSL_CONNECTION *s)
806 {
807 OSSL_STATEM *st = &s->statem;
808 int ret;
809 WRITE_TRAN (*transition)(SSL_CONNECTION *s);
810 WORK_STATE (*pre_work)(SSL_CONNECTION *s, WORK_STATE wst);
811 WORK_STATE (*post_work)(SSL_CONNECTION *s, WORK_STATE wst);
812 int (*get_construct_message_f)(SSL_CONNECTION *s,
813 CON_FUNC_RETURN (**confunc)(SSL_CONNECTION *s,
814 WPACKET *pkt),
815 int *mt);
816 void (*cb)(const SSL *ssl, int type, int val) = NULL;
817 CON_FUNC_RETURN (*confunc)(SSL_CONNECTION *s, WPACKET *pkt);
818 int mt;
819 WPACKET pkt;
820 SSL *ssl = SSL_CONNECTION_GET_USER_SSL(s);
821
822 cb = get_callback(s);
823
824 if (s->server) {
825 transition = ossl_statem_server_write_transition;
826 pre_work = ossl_statem_server_pre_work;
827 post_work = ossl_statem_server_post_work;
828 get_construct_message_f = ossl_statem_server_construct_message;
829 } else {
830 transition = ossl_statem_client_write_transition;
831 pre_work = ossl_statem_client_pre_work;
832 post_work = ossl_statem_client_post_work;
833 get_construct_message_f = ossl_statem_client_construct_message;
834 }
835
836 while (1) {
837 switch (st->write_state) {
838 case WRITE_STATE_TRANSITION:
839 if (cb != NULL) {
840 /* Notify callback of an impending state change */
841 if (s->server)
842 cb(ssl, SSL_CB_ACCEPT_LOOP, 1);
843 else
844 cb(ssl, SSL_CB_CONNECT_LOOP, 1);
845 }
846 switch (transition(s)) {
847 case WRITE_TRAN_CONTINUE:
848 st->write_state = WRITE_STATE_PRE_WORK;
849 st->write_state_work = WORK_MORE_A;
850 break;
851
852 case WRITE_TRAN_FINISHED:
853 return SUB_STATE_FINISHED;
854
855 case WRITE_TRAN_ERROR:
856 check_fatal(s);
857 return SUB_STATE_ERROR;
858 }
859 break;
860
861 case WRITE_STATE_PRE_WORK:
862 switch (st->write_state_work = pre_work(s, st->write_state_work)) {
863 case WORK_ERROR:
864 check_fatal(s);
865 /* Fall through */
866 case WORK_MORE_A:
867 case WORK_MORE_B:
868 case WORK_MORE_C:
869 return SUB_STATE_ERROR;
870
871 case WORK_FINISHED_CONTINUE:
872 st->write_state = WRITE_STATE_SEND;
873 break;
874
875 case WORK_FINISHED_SWAP:
876 return SUB_STATE_FINISHED;
877
878 case WORK_FINISHED_STOP:
879 return SUB_STATE_END_HANDSHAKE;
880 }
881 if (!get_construct_message_f(s, &confunc, &mt)) {
882 /* SSLfatal() already called */
883 return SUB_STATE_ERROR;
884 }
885 if (mt == SSL3_MT_DUMMY) {
886 /* Skip construction and sending. This isn't a "real" state */
887 st->write_state = WRITE_STATE_POST_WORK;
888 st->write_state_work = WORK_MORE_A;
889 break;
890 }
891 if (!WPACKET_init(&pkt, s->init_buf)
892 || !ssl_set_handshake_header(s, &pkt, mt)) {
893 WPACKET_cleanup(&pkt);
894 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
895 return SUB_STATE_ERROR;
896 }
897 if (confunc != NULL) {
898 CON_FUNC_RETURN tmpret;
899
900 tmpret = confunc(s, &pkt);
901 if (tmpret == CON_FUNC_ERROR) {
902 WPACKET_cleanup(&pkt);
903 check_fatal(s);
904 return SUB_STATE_ERROR;
905 } else if (tmpret == CON_FUNC_DONT_SEND) {
906 /*
907 * The construction function decided not to construct the
908 * message after all and continue. Skip sending.
909 */
910 WPACKET_cleanup(&pkt);
911 st->write_state = WRITE_STATE_POST_WORK;
912 st->write_state_work = WORK_MORE_A;
913 break;
914 } /* else success */
915 }
916 if (!ssl_close_construct_packet(s, &pkt, mt)
917 || !WPACKET_finish(&pkt)) {
918 WPACKET_cleanup(&pkt);
919 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
920 return SUB_STATE_ERROR;
921 }
922
923 /* Fall through */
924
925 case WRITE_STATE_SEND:
926 if (SSL_CONNECTION_IS_DTLS(s) && st->use_timer) {
927 dtls1_start_timer(s);
928 }
929 ret = statem_do_write(s);
930 if (ret <= 0) {
931 return SUB_STATE_ERROR;
932 }
933 st->write_state = WRITE_STATE_POST_WORK;
934 st->write_state_work = WORK_MORE_A;
935 /* Fall through */
936
937 case WRITE_STATE_POST_WORK:
938 switch (st->write_state_work = post_work(s, st->write_state_work)) {
939 case WORK_ERROR:
940 check_fatal(s);
941 /* Fall through */
942 case WORK_MORE_A:
943 case WORK_MORE_B:
944 case WORK_MORE_C:
945 return SUB_STATE_ERROR;
946
947 case WORK_FINISHED_CONTINUE:
948 st->write_state = WRITE_STATE_TRANSITION;
949 break;
950
951 case WORK_FINISHED_SWAP:
952 return SUB_STATE_FINISHED;
953
954 case WORK_FINISHED_STOP:
955 return SUB_STATE_END_HANDSHAKE;
956 }
957 break;
958
959 default:
960 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
961 return SUB_STATE_ERROR;
962 }
963 }
964 }
965
966 /*
967 * Flush the write BIO
968 */
statem_flush(SSL_CONNECTION * s)969 int statem_flush(SSL_CONNECTION *s)
970 {
971 s->rwstate = SSL_WRITING;
972 if (BIO_flush(s->wbio) <= 0) {
973 return 0;
974 }
975 s->rwstate = SSL_NOTHING;
976
977 return 1;
978 }
979
980 /*
981 * Called by the record layer to determine whether application data is
982 * allowed to be received in the current handshake state or not.
983 *
984 * Return values are:
985 * 1: Yes (application data allowed)
986 * 0: No (application data not allowed)
987 */
ossl_statem_app_data_allowed(SSL_CONNECTION * s)988 int ossl_statem_app_data_allowed(SSL_CONNECTION *s)
989 {
990 OSSL_STATEM *st = &s->statem;
991
992 if (st->state == MSG_FLOW_UNINITED)
993 return 0;
994
995 if (!s->s3.in_read_app_data || (s->s3.total_renegotiations == 0))
996 return 0;
997
998 if (s->server) {
999 /*
1000 * If we're a server and we haven't got as far as writing our
1001 * ServerHello yet then we allow app data
1002 */
1003 if (st->hand_state == TLS_ST_BEFORE
1004 || st->hand_state == TLS_ST_SR_CLNT_HELLO)
1005 return 1;
1006 } else {
1007 /*
1008 * If we're a client and we haven't read the ServerHello yet then we
1009 * allow app data
1010 */
1011 if (st->hand_state == TLS_ST_CW_CLNT_HELLO)
1012 return 1;
1013 }
1014
1015 return 0;
1016 }
1017
1018 /*
1019 * This function returns 1 if TLS exporter is ready to export keying
1020 * material, or 0 if otherwise.
1021 */
ossl_statem_export_allowed(SSL_CONNECTION * s)1022 int ossl_statem_export_allowed(SSL_CONNECTION *s)
1023 {
1024 return s->s3.previous_server_finished_len != 0
1025 && s->statem.hand_state != TLS_ST_SW_FINISHED;
1026 }
1027
1028 /*
1029 * Return 1 if early TLS exporter is ready to export keying material,
1030 * or 0 if otherwise.
1031 */
ossl_statem_export_early_allowed(SSL_CONNECTION * s)1032 int ossl_statem_export_early_allowed(SSL_CONNECTION *s)
1033 {
1034 /*
1035 * The early exporter secret is only present on the server if we
1036 * have accepted early_data. It is present on the client as long
1037 * as we have sent early_data.
1038 */
1039 return s->ext.early_data == SSL_EARLY_DATA_ACCEPTED
1040 || (!s->server && s->ext.early_data != SSL_EARLY_DATA_NOT_SENT);
1041 }
1042