1 /*
2 * Copyright 2015-2022 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 <openssl/rand.h>
19 #include "../ssl_local.h"
20 #include "statem_local.h"
21 #include <assert.h>
22
23 /*
24 * This file implements the SSL/TLS/DTLS state machines.
25 *
26 * There are two primary state machines:
27 *
28 * 1) Message flow state machine
29 * 2) Handshake state machine
30 *
31 * The Message flow state machine controls the reading and sending of messages
32 * including handling of non-blocking IO events, flushing of the underlying
33 * write BIO, handling unexpected messages, etc. It is itself broken into two
34 * separate sub-state machines which control reading and writing respectively.
35 *
36 * The Handshake state machine keeps track of the current SSL/TLS handshake
37 * state. Transitions of the handshake state are the result of events that
38 * occur within the Message flow state machine.
39 *
40 * Overall it looks like this:
41 *
42 * --------------------------------------------- -------------------
43 * | | | |
44 * | Message flow state machine | | |
45 * | | | |
46 * | -------------------- -------------------- | Transition | Handshake state |
47 * | | MSG_FLOW_READING | | MSG_FLOW_WRITING | | Event | machine |
48 * | | sub-state | | sub-state | |----------->| |
49 * | | machine for | | machine for | | | |
50 * | | reading messages | | writing messages | | | |
51 * | -------------------- -------------------- | | |
52 * | | | |
53 * --------------------------------------------- -------------------
54 *
55 */
56
57 /* Sub state machine return values */
58 typedef enum {
59 /* Something bad happened or NBIO */
60 SUB_STATE_ERROR,
61 /* Sub state finished go to the next sub state */
62 SUB_STATE_FINISHED,
63 /* Sub state finished and handshake was completed */
64 SUB_STATE_END_HANDSHAKE
65 } SUB_STATE_RETURN;
66
67 static int state_machine(SSL_CONNECTION *s, int server);
68 static void init_read_state_machine(SSL_CONNECTION *s);
69 static SUB_STATE_RETURN read_state_machine(SSL_CONNECTION *s);
70 static void init_write_state_machine(SSL_CONNECTION *s);
71 static SUB_STATE_RETURN write_state_machine(SSL_CONNECTION *s);
72
SSL_get_state(const SSL * ssl)73 OSSL_HANDSHAKE_STATE SSL_get_state(const SSL *ssl)
74 {
75 const SSL_CONNECTION *sc = SSL_CONNECTION_FROM_CONST_SSL(ssl);
76
77 if (sc == NULL)
78 return TLS_ST_BEFORE;
79
80 return sc->statem.hand_state;
81 }
82
SSL_in_init(const SSL * s)83 int SSL_in_init(const SSL *s)
84 {
85 const SSL_CONNECTION *sc = SSL_CONNECTION_FROM_CONST_SSL(s);
86
87 if (sc == NULL)
88 return 0;
89
90 return sc->statem.in_init;
91 }
92
SSL_is_init_finished(const SSL * s)93 int SSL_is_init_finished(const SSL *s)
94 {
95 const SSL_CONNECTION *sc = SSL_CONNECTION_FROM_CONST_SSL(s);
96
97 if (sc == NULL)
98 return 0;
99
100 return !(sc->statem.in_init) && (sc->statem.hand_state == TLS_ST_OK);
101 }
102
SSL_in_before(const SSL * s)103 int SSL_in_before(const SSL *s)
104 {
105 const SSL_CONNECTION *sc = SSL_CONNECTION_FROM_CONST_SSL(s);
106
107 if (sc == NULL)
108 return 0;
109
110 /*
111 * Historically being "in before" meant before anything had happened. In the
112 * current code though we remain in the "before" state for a while after we
113 * have started the handshake process (e.g. as a server waiting for the
114 * first message to arrive). There "in before" is taken to mean "in before"
115 * and not started any handshake process yet.
116 */
117 return (sc->statem.hand_state == TLS_ST_BEFORE)
118 && (sc->statem.state == MSG_FLOW_UNINITED);
119 }
120
ossl_statem_get_state(SSL_CONNECTION * s)121 OSSL_HANDSHAKE_STATE ossl_statem_get_state(SSL_CONNECTION *s)
122 {
123 return s != NULL ? s->statem.hand_state : TLS_ST_BEFORE;
124 }
125
126 /*
127 * Clear the state machine state and reset back to MSG_FLOW_UNINITED
128 */
ossl_statem_clear(SSL_CONNECTION * s)129 void ossl_statem_clear(SSL_CONNECTION *s)
130 {
131 s->statem.state = MSG_FLOW_UNINITED;
132 s->statem.hand_state = TLS_ST_BEFORE;
133 ossl_statem_set_in_init(s, 1);
134 s->statem.no_cert_verify = 0;
135 }
136
137 /*
138 * Set the state machine up ready for a renegotiation handshake
139 */
ossl_statem_set_renegotiate(SSL_CONNECTION * s)140 void ossl_statem_set_renegotiate(SSL_CONNECTION *s)
141 {
142 ossl_statem_set_in_init(s, 1);
143 s->statem.request_state = TLS_ST_SW_HELLO_REQ;
144 }
145
ossl_statem_send_fatal(SSL_CONNECTION * s,int al)146 void ossl_statem_send_fatal(SSL_CONNECTION *s, int al)
147 {
148 /* We shouldn't call SSLfatal() twice. Once is enough */
149 if (s->statem.in_init && s->statem.state == MSG_FLOW_ERROR)
150 return;
151 ossl_statem_set_in_init(s, 1);
152 s->statem.state = MSG_FLOW_ERROR;
153 if (al != SSL_AD_NO_ALERT)
154 ssl3_send_alert(s, SSL3_AL_FATAL, al);
155 }
156
157 /*
158 * Error reporting building block that's used instead of ERR_set_error().
159 * In addition to what ERR_set_error() does, this puts the state machine
160 * into an error state and sends an alert if appropriate.
161 * This is a permanent error for the current connection.
162 */
ossl_statem_fatal(SSL_CONNECTION * s,int al,int reason,const char * fmt,...)163 void ossl_statem_fatal(SSL_CONNECTION *s, int al, int reason,
164 const char *fmt, ...)
165 {
166 va_list args;
167
168 va_start(args, fmt);
169 ERR_vset_error(ERR_LIB_SSL, reason, fmt, args);
170 va_end(args);
171
172 ossl_statem_send_fatal(s, al);
173 }
174
175 /*
176 * This macro should only be called if we are already expecting to be in
177 * a fatal error state. We verify that we are, and set it if not (this would
178 * indicate a bug).
179 */
180 #define check_fatal(s) \
181 do { \
182 if (!ossl_assert((s)->statem.in_init \
183 && (s)->statem.state == MSG_FLOW_ERROR)) \
184 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_R_MISSING_FATAL); \
185 } while (0)
186
187 /*
188 * Discover whether the current connection is in the error state.
189 *
190 * Valid return values are:
191 * 1: Yes
192 * 0: No
193 */
ossl_statem_in_error(const SSL_CONNECTION * s)194 int ossl_statem_in_error(const SSL_CONNECTION *s)
195 {
196 if (s->statem.state == MSG_FLOW_ERROR)
197 return 1;
198
199 return 0;
200 }
201
ossl_statem_set_in_init(SSL_CONNECTION * s,int init)202 void ossl_statem_set_in_init(SSL_CONNECTION *s, int init)
203 {
204 s->statem.in_init = init;
205 if (s->rlayer.rrlmethod != NULL && s->rlayer.rrlmethod->set_in_init != NULL)
206 s->rlayer.rrlmethod->set_in_init(s->rlayer.rrl, init);
207 }
208
ossl_statem_get_in_handshake(SSL_CONNECTION * s)209 int ossl_statem_get_in_handshake(SSL_CONNECTION *s)
210 {
211 return s->statem.in_handshake;
212 }
213
ossl_statem_set_in_handshake(SSL_CONNECTION * s,int inhand)214 void ossl_statem_set_in_handshake(SSL_CONNECTION *s, int inhand)
215 {
216 if (inhand)
217 s->statem.in_handshake++;
218 else
219 s->statem.in_handshake--;
220 }
221
222 /* Are we in a sensible state to skip over unreadable early data? */
ossl_statem_skip_early_data(SSL_CONNECTION * s)223 int ossl_statem_skip_early_data(SSL_CONNECTION *s)
224 {
225 if (s->ext.early_data != SSL_EARLY_DATA_REJECTED)
226 return 0;
227
228 if (!s->server
229 || s->statem.hand_state != TLS_ST_EARLY_DATA
230 || s->hello_retry_request == SSL_HRR_COMPLETE)
231 return 0;
232
233 return 1;
234 }
235
236 /*
237 * Called when we are in SSL_read*(), SSL_write*(), or SSL_accept()
238 * /SSL_connect()/SSL_do_handshake(). Used to test whether we are in an early
239 * data state and whether we should attempt to move the handshake on if so.
240 * |sending| is 1 if we are attempting to send data (SSL_write*()), 0 if we are
241 * attempting to read data (SSL_read*()), or -1 if we are in SSL_do_handshake()
242 * or similar.
243 */
ossl_statem_check_finish_init(SSL_CONNECTION * s,int sending)244 void ossl_statem_check_finish_init(SSL_CONNECTION *s, int sending)
245 {
246 if (sending == -1) {
247 if (s->statem.hand_state == TLS_ST_PENDING_EARLY_DATA_END
248 || s->statem.hand_state == TLS_ST_EARLY_DATA) {
249 ossl_statem_set_in_init(s, 1);
250 if (s->early_data_state == SSL_EARLY_DATA_WRITE_RETRY) {
251 /*
252 * SSL_connect() or SSL_do_handshake() has been called directly.
253 * We don't allow any more writing of early data.
254 */
255 s->early_data_state = SSL_EARLY_DATA_FINISHED_WRITING;
256 }
257 }
258 } else if (!s->server) {
259 if ((sending && (s->statem.hand_state == TLS_ST_PENDING_EARLY_DATA_END
260 || 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 }
277
ossl_statem_set_hello_verify_done(SSL_CONNECTION * s)278 void ossl_statem_set_hello_verify_done(SSL_CONNECTION *s)
279 {
280 s->statem.state = MSG_FLOW_UNINITED;
281 ossl_statem_set_in_init(s, 1);
282 /*
283 * This will get reset (briefly) back to TLS_ST_BEFORE when we enter
284 * state_machine() because |state| is MSG_FLOW_UNINITED, but until then any
285 * calls to SSL_in_before() will return false. Also calls to
286 * SSL_state_string() and SSL_state_string_long() will return something
287 * sensible.
288 */
289 s->statem.hand_state = TLS_ST_SR_CLNT_HELLO;
290 }
291
ossl_statem_connect(SSL * s)292 int ossl_statem_connect(SSL *s)
293 {
294 SSL_CONNECTION *sc = SSL_CONNECTION_FROM_SSL(s);
295
296 if (sc == NULL)
297 return -1;
298
299 return state_machine(sc, 0);
300 }
301
ossl_statem_accept(SSL * s)302 int ossl_statem_accept(SSL *s)
303 {
304 SSL_CONNECTION *sc = SSL_CONNECTION_FROM_SSL(s);
305
306 if (sc == NULL)
307 return -1;
308
309 return state_machine(sc, 1);
310 }
311
312 typedef void (*info_cb) (const SSL *, int, int);
313
get_callback(SSL_CONNECTION * s)314 static info_cb get_callback(SSL_CONNECTION *s)
315 {
316 SSL_CTX *sctx = SSL_CONNECTION_GET_CTX(s);
317
318 if (s->info_callback != NULL)
319 return s->info_callback;
320 else if (sctx->info_callback != NULL)
321 return sctx->info_callback;
322
323 return NULL;
324 }
325
326 /*
327 * The main message flow state machine. We start in the MSG_FLOW_UNINITED or
328 * MSG_FLOW_FINISHED state and finish in MSG_FLOW_FINISHED. Valid states and
329 * transitions are as follows:
330 *
331 * MSG_FLOW_UNINITED MSG_FLOW_FINISHED
332 * | |
333 * +-----------------------+
334 * v
335 * MSG_FLOW_WRITING <---> MSG_FLOW_READING
336 * |
337 * V
338 * MSG_FLOW_FINISHED
339 * |
340 * V
341 * [SUCCESS]
342 *
343 * We may exit at any point due to an error or NBIO event. If an NBIO event
344 * occurs then we restart at the point we left off when we are recalled.
345 * MSG_FLOW_WRITING and MSG_FLOW_READING have sub-state machines associated with them.
346 *
347 * In addition to the above there is also the MSG_FLOW_ERROR state. We can move
348 * into that state at any point in the event that an irrecoverable error occurs.
349 *
350 * Valid return values are:
351 * 1: Success
352 * <=0: NBIO or error
353 */
state_machine(SSL_CONNECTION * s,int server)354 static int state_machine(SSL_CONNECTION *s, int server)
355 {
356 BUF_MEM *buf = NULL;
357 void (*cb) (const SSL *ssl, int type, int val) = NULL;
358 OSSL_STATEM *st = &s->statem;
359 int ret = -1;
360 int ssret;
361 SSL *ssl = SSL_CONNECTION_GET_SSL(s);
362
363 if (st->state == MSG_FLOW_ERROR) {
364 /* Shouldn't have been called if we're already in the error state */
365 return -1;
366 }
367
368 ERR_clear_error();
369 clear_sys_error();
370
371 cb = get_callback(s);
372
373 st->in_handshake++;
374 if (!SSL_in_init(ssl) || SSL_in_before(ssl)) {
375 /*
376 * If we are stateless then we already called SSL_clear() - don't do
377 * it again and clear the STATELESS flag itself.
378 */
379 if ((s->s3.flags & TLS1_FLAGS_STATELESS) == 0 && !SSL_clear(ssl))
380 return -1;
381 }
382 #ifndef OPENSSL_NO_SCTP
383 if (SSL_CONNECTION_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(ssl))) {
384 /*
385 * Notify SCTP BIO socket to enter handshake mode and prevent stream
386 * identifier other than 0.
387 */
388 BIO_ctrl(SSL_get_wbio(ssl), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
389 st->in_handshake, NULL);
390 }
391 #endif
392
393 /* Initialise state machine */
394 if (st->state == MSG_FLOW_UNINITED
395 || st->state == MSG_FLOW_FINISHED) {
396 if (st->state == MSG_FLOW_UNINITED) {
397 st->hand_state = TLS_ST_BEFORE;
398 st->request_state = TLS_ST_BEFORE;
399 }
400
401 s->server = server;
402 if (cb != NULL) {
403 if (SSL_IS_FIRST_HANDSHAKE(s) || !SSL_CONNECTION_IS_TLS13(s))
404 cb(ssl, SSL_CB_HANDSHAKE_START, 1);
405 }
406
407 /*
408 * Fatal errors in this block don't send an alert because we have
409 * failed to even initialise properly. Sending an alert is probably
410 * doomed to failure.
411 */
412
413 if (SSL_CONNECTION_IS_DTLS(s)) {
414 if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00) &&
415 (server || (s->version & 0xff00) != (DTLS1_BAD_VER & 0xff00))) {
416 SSLfatal(s, SSL_AD_NO_ALERT, ERR_R_INTERNAL_ERROR);
417 goto end;
418 }
419 } else {
420 if ((s->version >> 8) != SSL3_VERSION_MAJOR) {
421 SSLfatal(s, SSL_AD_NO_ALERT, ERR_R_INTERNAL_ERROR);
422 goto end;
423 }
424 }
425
426 if (!ssl_security(s, SSL_SECOP_VERSION, 0, s->version, NULL)) {
427 SSLfatal(s, SSL_AD_NO_ALERT, ERR_R_INTERNAL_ERROR);
428 goto end;
429 }
430
431 if (s->init_buf == NULL) {
432 if ((buf = BUF_MEM_new()) == NULL) {
433 SSLfatal(s, SSL_AD_NO_ALERT, ERR_R_INTERNAL_ERROR);
434 goto end;
435 }
436 if (!BUF_MEM_grow(buf, SSL3_RT_MAX_PLAIN_LENGTH)) {
437 SSLfatal(s, SSL_AD_NO_ALERT, ERR_R_INTERNAL_ERROR);
438 goto end;
439 }
440 s->init_buf = buf;
441 buf = NULL;
442 }
443
444 s->init_num = 0;
445
446 /*
447 * Should have been reset by tls_process_finished, too.
448 */
449 s->s3.change_cipher_spec = 0;
450
451 /*
452 * Ok, we now need to push on a buffering BIO ...but not with
453 * SCTP
454 */
455 #ifndef OPENSSL_NO_SCTP
456 if (!SSL_CONNECTION_IS_DTLS(s) || !BIO_dgram_is_sctp(SSL_get_wbio(ssl)))
457 #endif
458 if (!ssl_init_wbio_buffer(s)) {
459 SSLfatal(s, SSL_AD_NO_ALERT, ERR_R_INTERNAL_ERROR);
460 goto end;
461 }
462
463 if ((SSL_in_before(ssl))
464 || s->renegotiate) {
465 if (!tls_setup_handshake(s)) {
466 /* SSLfatal() already called */
467 goto end;
468 }
469
470 if (SSL_IS_FIRST_HANDSHAKE(s))
471 st->read_state_first_init = 1;
472 }
473
474 st->state = MSG_FLOW_WRITING;
475 init_write_state_machine(s);
476 }
477
478 while (st->state != MSG_FLOW_FINISHED) {
479 if (st->state == MSG_FLOW_READING) {
480 ssret = read_state_machine(s);
481 if (ssret == SUB_STATE_FINISHED) {
482 st->state = MSG_FLOW_WRITING;
483 init_write_state_machine(s);
484 } else {
485 /* NBIO or error */
486 goto end;
487 }
488 } else if (st->state == MSG_FLOW_WRITING) {
489 ssret = write_state_machine(s);
490 if (ssret == SUB_STATE_FINISHED) {
491 st->state = MSG_FLOW_READING;
492 init_read_state_machine(s);
493 } else if (ssret == SUB_STATE_END_HANDSHAKE) {
494 st->state = MSG_FLOW_FINISHED;
495 } else {
496 /* NBIO or error */
497 goto end;
498 }
499 } else {
500 /* Error */
501 check_fatal(s);
502 ERR_raise(ERR_LIB_SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
503 goto end;
504 }
505 }
506
507 ret = 1;
508
509 end:
510 st->in_handshake--;
511
512 #ifndef OPENSSL_NO_SCTP
513 if (SSL_CONNECTION_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(ssl))) {
514 /*
515 * Notify SCTP BIO socket to leave handshake mode and allow stream
516 * identifier other than 0.
517 */
518 BIO_ctrl(SSL_get_wbio(ssl), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
519 st->in_handshake, NULL);
520 }
521 #endif
522
523 BUF_MEM_free(buf);
524 if (cb != NULL) {
525 if (server)
526 cb(ssl, SSL_CB_ACCEPT_EXIT, ret);
527 else
528 cb(ssl, SSL_CB_CONNECT_EXIT, ret);
529 }
530 return ret;
531 }
532
533 /*
534 * Initialise the MSG_FLOW_READING sub-state machine
535 */
init_read_state_machine(SSL_CONNECTION * s)536 static void init_read_state_machine(SSL_CONNECTION *s)
537 {
538 OSSL_STATEM *st = &s->statem;
539
540 st->read_state = READ_STATE_HEADER;
541 }
542
grow_init_buf(SSL_CONNECTION * s,size_t size)543 static int grow_init_buf(SSL_CONNECTION *s, size_t size) {
544
545 size_t msg_offset = (char *)s->init_msg - s->init_buf->data;
546
547 if (!BUF_MEM_grow_clean(s->init_buf, (int)size))
548 return 0;
549
550 if (size < msg_offset)
551 return 0;
552
553 s->init_msg = s->init_buf->data + msg_offset;
554
555 return 1;
556 }
557
558 /*
559 * This function implements the sub-state machine when the message flow is in
560 * MSG_FLOW_READING. The valid sub-states and transitions are:
561 *
562 * READ_STATE_HEADER <--+<-------------+
563 * | | |
564 * v | |
565 * READ_STATE_BODY -----+-->READ_STATE_POST_PROCESS
566 * | |
567 * +----------------------------+
568 * v
569 * [SUB_STATE_FINISHED]
570 *
571 * READ_STATE_HEADER has the responsibility for reading in the message header
572 * and transitioning the state of the handshake state machine.
573 *
574 * READ_STATE_BODY reads in the rest of the message and then subsequently
575 * processes it.
576 *
577 * READ_STATE_POST_PROCESS is an optional step that may occur if some post
578 * processing activity performed on the message may block.
579 *
580 * Any of the above states could result in an NBIO event occurring in which case
581 * control returns to the calling application. When this function is recalled we
582 * will resume in the same state where we left off.
583 */
read_state_machine(SSL_CONNECTION * s)584 static SUB_STATE_RETURN read_state_machine(SSL_CONNECTION *s)
585 {
586 OSSL_STATEM *st = &s->statem;
587 int ret, mt;
588 size_t len = 0;
589 int (*transition) (SSL_CONNECTION *s, int mt);
590 PACKET pkt;
591 MSG_PROCESS_RETURN(*process_message) (SSL_CONNECTION *s, PACKET *pkt);
592 WORK_STATE(*post_process_message) (SSL_CONNECTION *s, WORK_STATE wst);
593 size_t (*max_message_size) (SSL_CONNECTION *s);
594 void (*cb) (const SSL *ssl, int type, int val) = NULL;
595 SSL *ssl = SSL_CONNECTION_GET_SSL(s);
596
597 cb = get_callback(s);
598
599 if (s->server) {
600 transition = ossl_statem_server_read_transition;
601 process_message = ossl_statem_server_process_message;
602 max_message_size = ossl_statem_server_max_message_size;
603 post_process_message = ossl_statem_server_post_process_message;
604 } else {
605 transition = ossl_statem_client_read_transition;
606 process_message = ossl_statem_client_process_message;
607 max_message_size = ossl_statem_client_max_message_size;
608 post_process_message = ossl_statem_client_post_process_message;
609 }
610
611 if (st->read_state_first_init) {
612 s->first_packet = 1;
613 st->read_state_first_init = 0;
614 }
615
616 while (1) {
617 switch (st->read_state) {
618 case READ_STATE_HEADER:
619 /* Get the state the peer wants to move to */
620 if (SSL_CONNECTION_IS_DTLS(s)) {
621 /*
622 * In DTLS we get the whole message in one go - header and body
623 */
624 ret = dtls_get_message(s, &mt);
625 } else {
626 ret = tls_get_message_header(s, &mt);
627 }
628
629 if (ret == 0) {
630 /* Could be non-blocking IO */
631 return SUB_STATE_ERROR;
632 }
633
634 if (cb != NULL) {
635 /* Notify callback of an impending state change */
636 if (s->server)
637 cb(ssl, SSL_CB_ACCEPT_LOOP, 1);
638 else
639 cb(ssl, SSL_CB_CONNECT_LOOP, 1);
640 }
641 /*
642 * Validate that we are allowed to move to the new state and move
643 * to that state if so
644 */
645 if (!transition(s, mt))
646 return SUB_STATE_ERROR;
647
648 if (s->s3.tmp.message_size > max_message_size(s)) {
649 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
650 SSL_R_EXCESSIVE_MESSAGE_SIZE);
651 return SUB_STATE_ERROR;
652 }
653
654 /* dtls_get_message already did this */
655 if (!SSL_CONNECTION_IS_DTLS(s)
656 && s->s3.tmp.message_size > 0
657 && !grow_init_buf(s, s->s3.tmp.message_size
658 + SSL3_HM_HEADER_LENGTH)) {
659 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_BUF_LIB);
660 return SUB_STATE_ERROR;
661 }
662
663 st->read_state = READ_STATE_BODY;
664 /* Fall through */
665
666 case READ_STATE_BODY:
667 if (SSL_CONNECTION_IS_DTLS(s)) {
668 /*
669 * Actually we already have the body, but we give DTLS the
670 * opportunity to do any further processing.
671 */
672 ret = dtls_get_message_body(s, &len);
673 } else {
674 ret = tls_get_message_body(s, &len);
675 }
676 if (ret == 0) {
677 /* Could be non-blocking IO */
678 return SUB_STATE_ERROR;
679 }
680
681 s->first_packet = 0;
682 if (!PACKET_buf_init(&pkt, s->init_msg, len)) {
683 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
684 return SUB_STATE_ERROR;
685 }
686 ret = process_message(s, &pkt);
687
688 /* Discard the packet data */
689 s->init_num = 0;
690
691 switch (ret) {
692 case MSG_PROCESS_ERROR:
693 check_fatal(s);
694 return SUB_STATE_ERROR;
695
696 case MSG_PROCESS_FINISHED_READING:
697 if (SSL_CONNECTION_IS_DTLS(s)) {
698 dtls1_stop_timer(s);
699 }
700 return SUB_STATE_FINISHED;
701
702 case MSG_PROCESS_CONTINUE_PROCESSING:
703 st->read_state = READ_STATE_POST_PROCESS;
704 st->read_state_work = WORK_MORE_A;
705 break;
706
707 default:
708 st->read_state = READ_STATE_HEADER;
709 break;
710 }
711 break;
712
713 case READ_STATE_POST_PROCESS:
714 st->read_state_work = post_process_message(s, st->read_state_work);
715 switch (st->read_state_work) {
716 case WORK_ERROR:
717 check_fatal(s);
718 /* Fall through */
719 case WORK_MORE_A:
720 case WORK_MORE_B:
721 case WORK_MORE_C:
722 return SUB_STATE_ERROR;
723
724 case WORK_FINISHED_CONTINUE:
725 st->read_state = READ_STATE_HEADER;
726 break;
727
728 case WORK_FINISHED_STOP:
729 if (SSL_CONNECTION_IS_DTLS(s)) {
730 dtls1_stop_timer(s);
731 }
732 return SUB_STATE_FINISHED;
733 }
734 break;
735
736 default:
737 /* Shouldn't happen */
738 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
739 return SUB_STATE_ERROR;
740 }
741 }
742 }
743
744 /*
745 * Send a previously constructed message to the peer.
746 */
statem_do_write(SSL_CONNECTION * s)747 static int statem_do_write(SSL_CONNECTION *s)
748 {
749 OSSL_STATEM *st = &s->statem;
750
751 if (st->hand_state == TLS_ST_CW_CHANGE
752 || st->hand_state == TLS_ST_SW_CHANGE) {
753 if (SSL_CONNECTION_IS_DTLS(s))
754 return dtls1_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC);
755 else
756 return ssl3_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC);
757 } else {
758 return ssl_do_write(s);
759 }
760 }
761
762 /*
763 * Initialise the MSG_FLOW_WRITING sub-state machine
764 */
init_write_state_machine(SSL_CONNECTION * s)765 static void init_write_state_machine(SSL_CONNECTION *s)
766 {
767 OSSL_STATEM *st = &s->statem;
768
769 st->write_state = WRITE_STATE_TRANSITION;
770 }
771
772 /*
773 * This function implements the sub-state machine when the message flow is in
774 * MSG_FLOW_WRITING. The valid sub-states and transitions are:
775 *
776 * +-> WRITE_STATE_TRANSITION ------> [SUB_STATE_FINISHED]
777 * | |
778 * | v
779 * | WRITE_STATE_PRE_WORK -----> [SUB_STATE_END_HANDSHAKE]
780 * | |
781 * | v
782 * | WRITE_STATE_SEND
783 * | |
784 * | v
785 * | WRITE_STATE_POST_WORK
786 * | |
787 * +-------------+
788 *
789 * WRITE_STATE_TRANSITION transitions the state of the handshake state machine
790
791 * WRITE_STATE_PRE_WORK performs any work necessary to prepare the later
792 * sending of the message. This could result in an NBIO event occurring in
793 * which case control returns to the calling application. When this function
794 * is recalled we will resume in the same state where we left off.
795 *
796 * WRITE_STATE_SEND sends the message and performs any work to be done after
797 * sending.
798 *
799 * WRITE_STATE_POST_WORK performs any work necessary after the sending of the
800 * message has been completed. As for WRITE_STATE_PRE_WORK this could also
801 * result in an NBIO event.
802 */
write_state_machine(SSL_CONNECTION * s)803 static SUB_STATE_RETURN write_state_machine(SSL_CONNECTION *s)
804 {
805 OSSL_STATEM *st = &s->statem;
806 int ret;
807 WRITE_TRAN(*transition) (SSL_CONNECTION *s);
808 WORK_STATE(*pre_work) (SSL_CONNECTION *s, WORK_STATE wst);
809 WORK_STATE(*post_work) (SSL_CONNECTION *s, WORK_STATE wst);
810 int (*get_construct_message_f) (SSL_CONNECTION *s,
811 CON_FUNC_RETURN (**confunc) (SSL_CONNECTION *s,
812 WPACKET *pkt),
813 int *mt);
814 void (*cb) (const SSL *ssl, int type, int val) = NULL;
815 CON_FUNC_RETURN (*confunc) (SSL_CONNECTION *s, WPACKET *pkt);
816 int mt;
817 WPACKET pkt;
818 SSL *ssl = SSL_CONNECTION_GET_SSL(s);
819
820 cb = get_callback(s);
821
822 if (s->server) {
823 transition = ossl_statem_server_write_transition;
824 pre_work = ossl_statem_server_pre_work;
825 post_work = ossl_statem_server_post_work;
826 get_construct_message_f = ossl_statem_server_construct_message;
827 } else {
828 transition = ossl_statem_client_write_transition;
829 pre_work = ossl_statem_client_pre_work;
830 post_work = ossl_statem_client_post_work;
831 get_construct_message_f = ossl_statem_client_construct_message;
832 }
833
834 while (1) {
835 switch (st->write_state) {
836 case WRITE_STATE_TRANSITION:
837 if (cb != NULL) {
838 /* Notify callback of an impending state change */
839 if (s->server)
840 cb(ssl, SSL_CB_ACCEPT_LOOP, 1);
841 else
842 cb(ssl, SSL_CB_CONNECT_LOOP, 1);
843 }
844 switch (transition(s)) {
845 case WRITE_TRAN_CONTINUE:
846 st->write_state = WRITE_STATE_PRE_WORK;
847 st->write_state_work = WORK_MORE_A;
848 break;
849
850 case WRITE_TRAN_FINISHED:
851 return SUB_STATE_FINISHED;
852 break;
853
854 case WRITE_TRAN_ERROR:
855 check_fatal(s);
856 return SUB_STATE_ERROR;
857 }
858 break;
859
860 case WRITE_STATE_PRE_WORK:
861 switch (st->write_state_work = pre_work(s, st->write_state_work)) {
862 case WORK_ERROR:
863 check_fatal(s);
864 /* Fall through */
865 case WORK_MORE_A:
866 case WORK_MORE_B:
867 case WORK_MORE_C:
868 return SUB_STATE_ERROR;
869
870 case WORK_FINISHED_CONTINUE:
871 st->write_state = WRITE_STATE_SEND;
872 break;
873
874 case WORK_FINISHED_STOP:
875 return SUB_STATE_END_HANDSHAKE;
876 }
877 if (!get_construct_message_f(s, &confunc, &mt)) {
878 /* SSLfatal() already called */
879 return SUB_STATE_ERROR;
880 }
881 if (mt == SSL3_MT_DUMMY) {
882 /* Skip construction and sending. This isn't a "real" state */
883 st->write_state = WRITE_STATE_POST_WORK;
884 st->write_state_work = WORK_MORE_A;
885 break;
886 }
887 if (!WPACKET_init(&pkt, s->init_buf)
888 || !ssl_set_handshake_header(s, &pkt, mt)) {
889 WPACKET_cleanup(&pkt);
890 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
891 return SUB_STATE_ERROR;
892 }
893 if (confunc != NULL) {
894 CON_FUNC_RETURN tmpret;
895
896 tmpret = confunc(s, &pkt);
897 if (tmpret == CON_FUNC_ERROR) {
898 WPACKET_cleanup(&pkt);
899 check_fatal(s);
900 return SUB_STATE_ERROR;
901 } else if (tmpret == CON_FUNC_DONT_SEND) {
902 /*
903 * The construction function decided not to construct the
904 * message after all and continue. Skip sending.
905 */
906 WPACKET_cleanup(&pkt);
907 st->write_state = WRITE_STATE_POST_WORK;
908 st->write_state_work = WORK_MORE_A;
909 break;
910 } /* else success */
911 }
912 if (!ssl_close_construct_packet(s, &pkt, mt)
913 || !WPACKET_finish(&pkt)) {
914 WPACKET_cleanup(&pkt);
915 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
916 return SUB_STATE_ERROR;
917 }
918
919 /* Fall through */
920
921 case WRITE_STATE_SEND:
922 if (SSL_CONNECTION_IS_DTLS(s) && st->use_timer) {
923 dtls1_start_timer(s);
924 }
925 ret = statem_do_write(s);
926 if (ret <= 0) {
927 return SUB_STATE_ERROR;
928 }
929 st->write_state = WRITE_STATE_POST_WORK;
930 st->write_state_work = WORK_MORE_A;
931 /* Fall through */
932
933 case WRITE_STATE_POST_WORK:
934 switch (st->write_state_work = post_work(s, st->write_state_work)) {
935 case WORK_ERROR:
936 check_fatal(s);
937 /* Fall through */
938 case WORK_MORE_A:
939 case WORK_MORE_B:
940 case WORK_MORE_C:
941 return SUB_STATE_ERROR;
942
943 case WORK_FINISHED_CONTINUE:
944 st->write_state = WRITE_STATE_TRANSITION;
945 break;
946
947 case WORK_FINISHED_STOP:
948 return SUB_STATE_END_HANDSHAKE;
949 }
950 break;
951
952 default:
953 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
954 return SUB_STATE_ERROR;
955 }
956 }
957 }
958
959 /*
960 * Flush the write BIO
961 */
statem_flush(SSL_CONNECTION * s)962 int statem_flush(SSL_CONNECTION *s)
963 {
964 s->rwstate = SSL_WRITING;
965 if (BIO_flush(s->wbio) <= 0) {
966 return 0;
967 }
968 s->rwstate = SSL_NOTHING;
969
970 return 1;
971 }
972
973 /*
974 * Called by the record layer to determine whether application data is
975 * allowed to be received in the current handshake state or not.
976 *
977 * Return values are:
978 * 1: Yes (application data allowed)
979 * 0: No (application data not allowed)
980 */
ossl_statem_app_data_allowed(SSL_CONNECTION * s)981 int ossl_statem_app_data_allowed(SSL_CONNECTION *s)
982 {
983 OSSL_STATEM *st = &s->statem;
984
985 if (st->state == MSG_FLOW_UNINITED)
986 return 0;
987
988 if (!s->s3.in_read_app_data || (s->s3.total_renegotiations == 0))
989 return 0;
990
991 if (s->server) {
992 /*
993 * If we're a server and we haven't got as far as writing our
994 * ServerHello yet then we allow app data
995 */
996 if (st->hand_state == TLS_ST_BEFORE
997 || st->hand_state == TLS_ST_SR_CLNT_HELLO)
998 return 1;
999 } else {
1000 /*
1001 * If we're a client and we haven't read the ServerHello yet then we
1002 * allow app data
1003 */
1004 if (st->hand_state == TLS_ST_CW_CLNT_HELLO)
1005 return 1;
1006 }
1007
1008 return 0;
1009 }
1010
1011 /*
1012 * This function returns 1 if TLS exporter is ready to export keying
1013 * material, or 0 if otherwise.
1014 */
ossl_statem_export_allowed(SSL_CONNECTION * s)1015 int ossl_statem_export_allowed(SSL_CONNECTION *s)
1016 {
1017 return s->s3.previous_server_finished_len != 0
1018 && s->statem.hand_state != TLS_ST_SW_FINISHED;
1019 }
1020
1021 /*
1022 * Return 1 if early TLS exporter is ready to export keying material,
1023 * or 0 if otherwise.
1024 */
ossl_statem_export_early_allowed(SSL_CONNECTION * s)1025 int ossl_statem_export_early_allowed(SSL_CONNECTION *s)
1026 {
1027 /*
1028 * The early exporter secret is only present on the server if we
1029 * have accepted early_data. It is present on the client as long
1030 * as we have sent early_data.
1031 */
1032 return s->ext.early_data == SSL_EARLY_DATA_ACCEPTED
1033 || (!s->server && s->ext.early_data != SSL_EARLY_DATA_NOT_SENT);
1034 }
1035