2 * Copyright 2015-2017 The OpenSSL Project Authors. All Rights Reserved.
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
10 #include "internal/cryptlib.h"
11 #include <openssl/rand.h>
12 #include "../ssl_locl.h"
13 #include "statem_locl.h"
16 * This file implements the SSL/TLS/DTLS state machines.
18 * There are two primary state machines:
20 * 1) Message flow state machine
21 * 2) Handshake state machine
23 * The Message flow state machine controls the reading and sending of messages
24 * including handling of non-blocking IO events, flushing of the underlying
25 * write BIO, handling unexpected messages, etc. It is itself broken into two
26 * separate sub-state machines which control reading and writing respectively.
28 * The Handshake state machine keeps track of the current SSL/TLS handshake
29 * state. Transitions of the handshake state are the result of events that
30 * occur within the Message flow state machine.
32 * Overall it looks like this:
34 * --------------------------------------------- -------------------
36 * | Message flow state machine | | |
38 * | -------------------- -------------------- | Transition | Handshake state |
39 * | | MSG_FLOW_READING | | MSG_FLOW_WRITING | | Event | machine |
40 * | | sub-state | | sub-state | |----------->| |
41 * | | machine for | | machine for | | | |
42 * | | reading messages | | writing messages | | | |
43 * | -------------------- -------------------- | | |
45 * --------------------------------------------- -------------------
49 /* Sub state machine return values */
51 /* Something bad happened or NBIO */
53 /* Sub state finished go to the next sub state */
55 /* Sub state finished and handshake was completed */
56 SUB_STATE_END_HANDSHAKE
59 static int state_machine(SSL *s, int server);
60 static void init_read_state_machine(SSL *s);
61 static SUB_STATE_RETURN read_state_machine(SSL *s);
62 static void init_write_state_machine(SSL *s);
63 static SUB_STATE_RETURN write_state_machine(SSL *s);
65 OSSL_HANDSHAKE_STATE SSL_get_state(const SSL *ssl)
67 return ssl->statem.hand_state;
70 int SSL_in_init(SSL *s)
72 return s->statem.in_init;
75 int SSL_is_init_finished(SSL *s)
77 return !(s->statem.in_init) && (s->statem.hand_state == TLS_ST_OK);
80 int SSL_in_before(SSL *s)
83 * Historically being "in before" meant before anything had happened. In the
84 * current code though we remain in the "before" state for a while after we
85 * have started the handshake process (e.g. as a server waiting for the
86 * first message to arrive). There "in before" is taken to mean "in before"
87 * and not started any handshake process yet.
89 return (s->statem.hand_state == TLS_ST_BEFORE)
90 && (s->statem.state == MSG_FLOW_UNINITED);
94 * Clear the state machine state and reset back to MSG_FLOW_UNINITED
96 void ossl_statem_clear(SSL *s)
98 s->statem.state = MSG_FLOW_UNINITED;
99 s->statem.hand_state = TLS_ST_BEFORE;
100 s->statem.in_init = 1;
101 s->statem.no_cert_verify = 0;
105 * Set the state machine up ready for a renegotiation handshake
107 void ossl_statem_set_renegotiate(SSL *s)
109 s->statem.in_init = 1;
110 s->statem.request_state = TLS_ST_SW_HELLO_REQ;
114 * Put the state machine into an error state and send an alert if appropriate.
115 * This is a permanent error for the current connection.
117 void ossl_statem_fatal(SSL *s, int al, int func, int reason, const char *file,
120 s->statem.in_init = 1;
121 s->statem.state = MSG_FLOW_ERROR;
122 ERR_put_error(ERR_LIB_SSL, func, reason, file, line);
123 if (al != SSL_AD_NO_ALERT)
124 ssl3_send_alert(s, SSL3_AL_FATAL, al);
128 * This macro should only be called if we are already expecting to be in
129 * a fatal error state. We verify that we are, and set it if not (this would
132 #define check_fatal(s, f) \
134 if (!ossl_assert((s)->statem.in_init \
135 || (s)->statem.state != MSG_FLOW_ERROR)) \
136 SSLfatal(s, SSL_AD_INTERNAL_ERROR, (f), \
137 SSL_R_MISSING_FATAL); \
141 * Discover whether the current connection is in the error state.
143 * Valid return values are:
147 int ossl_statem_in_error(const SSL *s)
149 if (s->statem.state == MSG_FLOW_ERROR)
155 void ossl_statem_set_in_init(SSL *s, int init)
157 s->statem.in_init = init;
160 int ossl_statem_get_in_handshake(SSL *s)
162 return s->statem.in_handshake;
165 void ossl_statem_set_in_handshake(SSL *s, int inhand)
168 s->statem.in_handshake++;
170 s->statem.in_handshake--;
173 /* Are we in a sensible state to skip over unreadable early data? */
174 int ossl_statem_skip_early_data(SSL *s)
176 if (s->ext.early_data != SSL_EARLY_DATA_REJECTED)
179 if (!s->server || s->statem.hand_state != TLS_ST_EARLY_DATA)
186 * Called when we are in SSL_read*(), SSL_write*(), or SSL_accept()
187 * /SSL_connect()/SSL_do_handshake(). Used to test whether we are in an early
188 * data state and whether we should attempt to move the handshake on if so.
189 * |sending| is 1 if we are attempting to send data (SSL_write*()), 0 if we are
190 * attempting to read data (SSL_read*()), or -1 if we are in SSL_do_handshake()
193 void ossl_statem_check_finish_init(SSL *s, int sending)
196 if (s->statem.hand_state == TLS_ST_PENDING_EARLY_DATA_END
197 || s->statem.hand_state == TLS_ST_EARLY_DATA) {
198 ossl_statem_set_in_init(s, 1);
199 if (s->early_data_state == SSL_EARLY_DATA_WRITE_RETRY) {
201 * SSL_connect() or SSL_do_handshake() has been called directly.
202 * We don't allow any more writing of early data.
204 s->early_data_state = SSL_EARLY_DATA_FINISHED_WRITING;
207 } else if (!s->server) {
208 if ((sending && (s->statem.hand_state == TLS_ST_PENDING_EARLY_DATA_END
209 || s->statem.hand_state == TLS_ST_EARLY_DATA)
210 && s->early_data_state != SSL_EARLY_DATA_WRITING)
211 || (!sending && s->statem.hand_state == TLS_ST_EARLY_DATA)) {
212 ossl_statem_set_in_init(s, 1);
214 * SSL_write() has been called directly. We don't allow any more
215 * writing of early data.
217 if (sending && s->early_data_state == SSL_EARLY_DATA_WRITE_RETRY)
218 s->early_data_state = SSL_EARLY_DATA_FINISHED_WRITING;
221 if (s->early_data_state == SSL_EARLY_DATA_FINISHED_READING
222 && s->statem.hand_state == TLS_ST_EARLY_DATA)
223 ossl_statem_set_in_init(s, 1);
227 void ossl_statem_set_hello_verify_done(SSL *s)
229 s->statem.state = MSG_FLOW_UNINITED;
230 s->statem.in_init = 1;
232 * This will get reset (briefly) back to TLS_ST_BEFORE when we enter
233 * state_machine() because |state| is MSG_FLOW_UNINITED, but until then any
234 * calls to SSL_in_before() will return false. Also calls to
235 * SSL_state_string() and SSL_state_string_long() will return something
238 s->statem.hand_state = TLS_ST_SR_CLNT_HELLO;
241 int ossl_statem_connect(SSL *s)
243 return state_machine(s, 0);
246 int ossl_statem_accept(SSL *s)
248 return state_machine(s, 1);
251 typedef void (*info_cb) (const SSL *, int, int);
253 static info_cb get_callback(SSL *s)
255 if (s->info_callback != NULL)
256 return s->info_callback;
257 else if (s->ctx->info_callback != NULL)
258 return s->ctx->info_callback;
264 * The main message flow state machine. We start in the MSG_FLOW_UNINITED or
265 * MSG_FLOW_FINISHED state and finish in MSG_FLOW_FINISHED. Valid states and
266 * transitions are as follows:
268 * MSG_FLOW_UNINITED MSG_FLOW_FINISHED
270 * +-----------------------+
272 * MSG_FLOW_WRITING <---> MSG_FLOW_READING
280 * We may exit at any point due to an error or NBIO event. If an NBIO event
281 * occurs then we restart at the point we left off when we are recalled.
282 * MSG_FLOW_WRITING and MSG_FLOW_READING have sub-state machines associated with them.
284 * In addition to the above there is also the MSG_FLOW_ERROR state. We can move
285 * into that state at any point in the event that an irrecoverable error occurs.
287 * Valid return values are:
291 static int state_machine(SSL *s, int server)
294 void (*cb) (const SSL *ssl, int type, int val) = NULL;
295 OSSL_STATEM *st = &s->statem;
299 if (st->state == MSG_FLOW_ERROR) {
300 /* Shouldn't have been called if we're already in the error state */
307 cb = get_callback(s);
310 if (!SSL_in_init(s) || SSL_in_before(s)) {
314 #ifndef OPENSSL_NO_SCTP
315 if (SSL_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(s))) {
317 * Notify SCTP BIO socket to enter handshake mode and prevent stream
318 * identifier other than 0.
320 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
321 st->in_handshake, NULL);
325 /* Initialise state machine */
326 if (st->state == MSG_FLOW_UNINITED
327 || st->state == MSG_FLOW_FINISHED) {
328 if (st->state == MSG_FLOW_UNINITED) {
329 st->hand_state = TLS_ST_BEFORE;
330 st->request_state = TLS_ST_BEFORE;
335 cb(s, SSL_CB_HANDSHAKE_START, 1);
338 * Fatal errors in this block don't send an alert because we have
339 * failed to even initialise properly. Sending an alert is probably
343 if (SSL_IS_DTLS(s)) {
344 if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00) &&
345 (server || (s->version & 0xff00) != (DTLS1_BAD_VER & 0xff00))) {
346 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE,
347 ERR_R_INTERNAL_ERROR);
351 if ((s->version >> 8) != SSL3_VERSION_MAJOR) {
352 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE,
353 ERR_R_INTERNAL_ERROR);
358 if (!ssl_security(s, SSL_SECOP_VERSION, 0, s->version, NULL)) {
359 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE,
360 ERR_R_INTERNAL_ERROR);
364 if (s->init_buf == NULL) {
365 if ((buf = BUF_MEM_new()) == NULL) {
366 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE,
367 ERR_R_INTERNAL_ERROR);
370 if (!BUF_MEM_grow(buf, SSL3_RT_MAX_PLAIN_LENGTH)) {
371 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE,
372 ERR_R_INTERNAL_ERROR);
379 if (!ssl3_setup_buffers(s)) {
380 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE,
381 ERR_R_INTERNAL_ERROR);
387 * Should have been reset by tls_process_finished, too.
389 s->s3->change_cipher_spec = 0;
392 * Ok, we now need to push on a buffering BIO ...but not with
395 #ifndef OPENSSL_NO_SCTP
396 if (!SSL_IS_DTLS(s) || !BIO_dgram_is_sctp(SSL_get_wbio(s)))
398 if (!ssl_init_wbio_buffer(s)) {
399 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE,
400 ERR_R_INTERNAL_ERROR);
404 if ((SSL_in_before(s))
406 if (!tls_setup_handshake(s)) {
407 /* SSLfatal() already called */
411 if (SSL_IS_FIRST_HANDSHAKE(s))
412 st->read_state_first_init = 1;
415 st->state = MSG_FLOW_WRITING;
416 init_write_state_machine(s);
419 while (st->state != MSG_FLOW_FINISHED) {
420 if (st->state == MSG_FLOW_READING) {
421 ssret = read_state_machine(s);
422 if (ssret == SUB_STATE_FINISHED) {
423 st->state = MSG_FLOW_WRITING;
424 init_write_state_machine(s);
429 } else if (st->state == MSG_FLOW_WRITING) {
430 ssret = write_state_machine(s);
431 if (ssret == SUB_STATE_FINISHED) {
432 st->state = MSG_FLOW_READING;
433 init_read_state_machine(s);
434 } else if (ssret == SUB_STATE_END_HANDSHAKE) {
435 st->state = MSG_FLOW_FINISHED;
442 check_fatal(s, SSL_F_STATE_MACHINE);
443 SSLerr(SSL_F_STATE_MACHINE, ERR_R_INTERNAL_ERROR);
453 #ifndef OPENSSL_NO_SCTP
454 if (SSL_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(s))) {
456 * Notify SCTP BIO socket to leave handshake mode and allow stream
457 * identifier other than 0.
459 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
460 st->in_handshake, NULL);
467 cb(s, SSL_CB_ACCEPT_EXIT, ret);
469 cb(s, SSL_CB_CONNECT_EXIT, ret);
475 * Initialise the MSG_FLOW_READING sub-state machine
477 static void init_read_state_machine(SSL *s)
479 OSSL_STATEM *st = &s->statem;
481 st->read_state = READ_STATE_HEADER;
484 static int grow_init_buf(SSL *s, size_t size) {
486 size_t msg_offset = (char *)s->init_msg - s->init_buf->data;
488 if (!BUF_MEM_grow_clean(s->init_buf, (int)size))
491 if (size < msg_offset)
494 s->init_msg = s->init_buf->data + msg_offset;
500 * This function implements the sub-state machine when the message flow is in
501 * MSG_FLOW_READING. The valid sub-states and transitions are:
503 * READ_STATE_HEADER <--+<-------------+
506 * READ_STATE_BODY -----+-->READ_STATE_POST_PROCESS
508 * +----------------------------+
510 * [SUB_STATE_FINISHED]
512 * READ_STATE_HEADER has the responsibility for reading in the message header
513 * and transitioning the state of the handshake state machine.
515 * READ_STATE_BODY reads in the rest of the message and then subsequently
518 * READ_STATE_POST_PROCESS is an optional step that may occur if some post
519 * processing activity performed on the message may block.
521 * Any of the above states could result in an NBIO event occurring in which case
522 * control returns to the calling application. When this function is recalled we
523 * will resume in the same state where we left off.
525 static SUB_STATE_RETURN read_state_machine(SSL *s)
527 OSSL_STATEM *st = &s->statem;
530 int (*transition) (SSL *s, int mt);
532 MSG_PROCESS_RETURN(*process_message) (SSL *s, PACKET *pkt);
533 WORK_STATE(*post_process_message) (SSL *s, WORK_STATE wst);
534 size_t (*max_message_size) (SSL *s);
535 void (*cb) (const SSL *ssl, int type, int val) = NULL;
537 cb = get_callback(s);
540 transition = ossl_statem_server_read_transition;
541 process_message = ossl_statem_server_process_message;
542 max_message_size = ossl_statem_server_max_message_size;
543 post_process_message = ossl_statem_server_post_process_message;
545 transition = ossl_statem_client_read_transition;
546 process_message = ossl_statem_client_process_message;
547 max_message_size = ossl_statem_client_max_message_size;
548 post_process_message = ossl_statem_client_post_process_message;
551 if (st->read_state_first_init) {
553 st->read_state_first_init = 0;
557 switch (st->read_state) {
558 case READ_STATE_HEADER:
559 /* Get the state the peer wants to move to */
560 if (SSL_IS_DTLS(s)) {
562 * In DTLS we get the whole message in one go - header and body
564 ret = dtls_get_message(s, &mt, &len);
566 ret = tls_get_message_header(s, &mt);
570 /* Could be non-blocking IO */
571 return SUB_STATE_ERROR;
575 /* Notify callback of an impending state change */
577 cb(s, SSL_CB_ACCEPT_LOOP, 1);
579 cb(s, SSL_CB_CONNECT_LOOP, 1);
582 * Validate that we are allowed to move to the new state and move
583 * to that state if so
585 if (!transition(s, mt)) {
586 check_fatal(s, SSL_F_READ_STATE_MACHINE);
587 return SUB_STATE_ERROR;
590 if (s->s3->tmp.message_size > max_message_size(s)) {
591 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_READ_STATE_MACHINE,
592 SSL_R_EXCESSIVE_MESSAGE_SIZE);
593 return SUB_STATE_ERROR;
596 /* dtls_get_message already did this */
598 && s->s3->tmp.message_size > 0
599 && !grow_init_buf(s, s->s3->tmp.message_size
600 + SSL3_HM_HEADER_LENGTH)) {
601 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_READ_STATE_MACHINE,
603 return SUB_STATE_ERROR;
606 st->read_state = READ_STATE_BODY;
609 case READ_STATE_BODY:
610 if (!SSL_IS_DTLS(s)) {
611 /* We already got this above for DTLS */
612 ret = tls_get_message_body(s, &len);
614 /* Could be non-blocking IO */
615 return SUB_STATE_ERROR;
620 if (!PACKET_buf_init(&pkt, s->init_msg, len)) {
621 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_READ_STATE_MACHINE,
622 ERR_R_INTERNAL_ERROR);
623 return SUB_STATE_ERROR;
625 ret = process_message(s, &pkt);
627 /* Discard the packet data */
631 case MSG_PROCESS_ERROR:
632 check_fatal(s, SSL_F_READ_STATE_MACHINE);
633 return SUB_STATE_ERROR;
635 case MSG_PROCESS_FINISHED_READING:
636 if (SSL_IS_DTLS(s)) {
639 return SUB_STATE_FINISHED;
641 case MSG_PROCESS_CONTINUE_PROCESSING:
642 st->read_state = READ_STATE_POST_PROCESS;
643 st->read_state_work = WORK_MORE_A;
647 st->read_state = READ_STATE_HEADER;
652 case READ_STATE_POST_PROCESS:
653 st->read_state_work = post_process_message(s, st->read_state_work);
654 switch (st->read_state_work) {
656 check_fatal(s, SSL_F_READ_STATE_MACHINE);
661 return SUB_STATE_ERROR;
663 case WORK_FINISHED_CONTINUE:
664 st->read_state = READ_STATE_HEADER;
667 case WORK_FINISHED_STOP:
668 if (SSL_IS_DTLS(s)) {
671 return SUB_STATE_FINISHED;
676 /* Shouldn't happen */
677 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_READ_STATE_MACHINE,
678 ERR_R_INTERNAL_ERROR);
679 return SUB_STATE_ERROR;
685 * Send a previously constructed message to the peer.
687 static int statem_do_write(SSL *s)
689 OSSL_STATEM *st = &s->statem;
691 if (st->hand_state == TLS_ST_CW_CHANGE
692 || st->hand_state == TLS_ST_SW_CHANGE) {
694 return dtls1_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC);
696 return ssl3_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC);
698 return ssl_do_write(s);
703 * Initialise the MSG_FLOW_WRITING sub-state machine
705 static void init_write_state_machine(SSL *s)
707 OSSL_STATEM *st = &s->statem;
709 st->write_state = WRITE_STATE_TRANSITION;
713 * This function implements the sub-state machine when the message flow is in
714 * MSG_FLOW_WRITING. The valid sub-states and transitions are:
716 * +-> WRITE_STATE_TRANSITION ------> [SUB_STATE_FINISHED]
719 * | WRITE_STATE_PRE_WORK -----> [SUB_STATE_END_HANDSHAKE]
725 * | WRITE_STATE_POST_WORK
729 * WRITE_STATE_TRANSITION transitions the state of the handshake state machine
731 * WRITE_STATE_PRE_WORK performs any work necessary to prepare the later
732 * sending of the message. This could result in an NBIO event occurring in
733 * which case control returns to the calling application. When this function
734 * is recalled we will resume in the same state where we left off.
736 * WRITE_STATE_SEND sends the message and performs any work to be done after
739 * WRITE_STATE_POST_WORK performs any work necessary after the sending of the
740 * message has been completed. As for WRITE_STATE_PRE_WORK this could also
741 * result in an NBIO event.
743 static SUB_STATE_RETURN write_state_machine(SSL *s)
745 OSSL_STATEM *st = &s->statem;
747 WRITE_TRAN(*transition) (SSL *s);
748 WORK_STATE(*pre_work) (SSL *s, WORK_STATE wst);
749 WORK_STATE(*post_work) (SSL *s, WORK_STATE wst);
750 int (*get_construct_message_f) (SSL *s, WPACKET *pkt,
751 int (**confunc) (SSL *s, WPACKET *pkt),
753 void (*cb) (const SSL *ssl, int type, int val) = NULL;
754 int (*confunc) (SSL *s, WPACKET *pkt);
758 cb = get_callback(s);
761 transition = ossl_statem_server_write_transition;
762 pre_work = ossl_statem_server_pre_work;
763 post_work = ossl_statem_server_post_work;
764 get_construct_message_f = ossl_statem_server_construct_message;
766 transition = ossl_statem_client_write_transition;
767 pre_work = ossl_statem_client_pre_work;
768 post_work = ossl_statem_client_post_work;
769 get_construct_message_f = ossl_statem_client_construct_message;
773 switch (st->write_state) {
774 case WRITE_STATE_TRANSITION:
776 /* Notify callback of an impending state change */
778 cb(s, SSL_CB_ACCEPT_LOOP, 1);
780 cb(s, SSL_CB_CONNECT_LOOP, 1);
782 switch (transition(s)) {
783 case WRITE_TRAN_CONTINUE:
784 st->write_state = WRITE_STATE_PRE_WORK;
785 st->write_state_work = WORK_MORE_A;
788 case WRITE_TRAN_FINISHED:
789 return SUB_STATE_FINISHED;
792 case WRITE_TRAN_ERROR:
793 check_fatal(s, SSL_F_WRITE_STATE_MACHINE);
794 return SUB_STATE_ERROR;
798 case WRITE_STATE_PRE_WORK:
799 switch (st->write_state_work = pre_work(s, st->write_state_work)) {
801 check_fatal(s, SSL_F_WRITE_STATE_MACHINE);
806 return SUB_STATE_ERROR;
808 case WORK_FINISHED_CONTINUE:
809 st->write_state = WRITE_STATE_SEND;
812 case WORK_FINISHED_STOP:
813 return SUB_STATE_END_HANDSHAKE;
815 if (!get_construct_message_f(s, &pkt, &confunc, &mt)) {
816 /* SSLfatal() already called */
817 return SUB_STATE_ERROR;
819 if (mt == SSL3_MT_DUMMY) {
820 /* Skip construction and sending. This isn't a "real" state */
821 st->write_state = WRITE_STATE_POST_WORK;
822 st->write_state_work = WORK_MORE_A;
825 if (!WPACKET_init(&pkt, s->init_buf)
826 || !ssl_set_handshake_header(s, &pkt, mt)) {
827 WPACKET_cleanup(&pkt);
828 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_WRITE_STATE_MACHINE,
829 ERR_R_INTERNAL_ERROR);
830 return SUB_STATE_ERROR;
832 if (confunc != NULL && !confunc(s, &pkt)) {
833 WPACKET_cleanup(&pkt);
834 check_fatal(s, SSL_F_WRITE_STATE_MACHINE);
835 return SUB_STATE_ERROR;
837 if (!ssl_close_construct_packet(s, &pkt, mt)
838 || !WPACKET_finish(&pkt)) {
839 WPACKET_cleanup(&pkt);
840 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_WRITE_STATE_MACHINE,
841 ERR_R_INTERNAL_ERROR);
842 return SUB_STATE_ERROR;
847 case WRITE_STATE_SEND:
848 if (SSL_IS_DTLS(s) && st->use_timer) {
849 dtls1_start_timer(s);
851 ret = statem_do_write(s);
853 return SUB_STATE_ERROR;
855 st->write_state = WRITE_STATE_POST_WORK;
856 st->write_state_work = WORK_MORE_A;
859 case WRITE_STATE_POST_WORK:
860 switch (st->write_state_work = post_work(s, st->write_state_work)) {
862 check_fatal(s, SSL_F_WRITE_STATE_MACHINE);
867 return SUB_STATE_ERROR;
869 case WORK_FINISHED_CONTINUE:
870 st->write_state = WRITE_STATE_TRANSITION;
873 case WORK_FINISHED_STOP:
874 return SUB_STATE_END_HANDSHAKE;
879 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_WRITE_STATE_MACHINE,
880 ERR_R_INTERNAL_ERROR);
881 return SUB_STATE_ERROR;
887 * Flush the write BIO
889 int statem_flush(SSL *s)
891 s->rwstate = SSL_WRITING;
892 if (BIO_flush(s->wbio) <= 0) {
895 s->rwstate = SSL_NOTHING;
901 * Called by the record layer to determine whether application data is
902 * allowed to be received in the current handshake state or not.
905 * 1: Yes (application data allowed)
906 * 0: No (application data not allowed)
908 int ossl_statem_app_data_allowed(SSL *s)
910 OSSL_STATEM *st = &s->statem;
912 if (st->state == MSG_FLOW_UNINITED)
915 if (!s->s3->in_read_app_data || (s->s3->total_renegotiations == 0))
920 * If we're a server and we haven't got as far as writing our
921 * ServerHello yet then we allow app data
923 if (st->hand_state == TLS_ST_BEFORE
924 || st->hand_state == TLS_ST_SR_CLNT_HELLO)
928 * If we're a client and we haven't read the ServerHello yet then we
931 if (st->hand_state == TLS_ST_CW_CLNT_HELLO)