1 /*
2 * Copyright 2005-2022 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 #include <stdio.h>
12 #include <openssl/objects.h>
13 #include <openssl/rand.h>
14 #include "ssl_local.h"
15 #include "internal/time.h"
16
17 static void get_current_time(struct timeval *t);
18 static int dtls1_handshake_write(SSL_CONNECTION *s);
19 static size_t dtls1_link_min_mtu(void);
20
21 /* XDTLS: figure out the right values */
22 static const size_t g_probable_mtu[] = { 1500, 512, 256 };
23
24 const SSL3_ENC_METHOD DTLSv1_enc_data = {
25 tls1_enc,
26 tls1_mac_old,
27 tls1_setup_key_block,
28 tls1_generate_master_secret,
29 tls1_change_cipher_state,
30 tls1_final_finish_mac,
31 TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
32 TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
33 tls1_alert_code,
34 tls1_export_keying_material,
35 SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV,
36 dtls1_set_handshake_header,
37 dtls1_close_construct_packet,
38 dtls1_handshake_write
39 };
40
41 const SSL3_ENC_METHOD DTLSv1_2_enc_data = {
42 tls1_enc,
43 tls1_mac_old,
44 tls1_setup_key_block,
45 tls1_generate_master_secret,
46 tls1_change_cipher_state,
47 tls1_final_finish_mac,
48 TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
49 TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
50 tls1_alert_code,
51 tls1_export_keying_material,
52 SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV | SSL_ENC_FLAG_SIGALGS
53 | SSL_ENC_FLAG_SHA256_PRF | SSL_ENC_FLAG_TLS1_2_CIPHERS,
54 dtls1_set_handshake_header,
55 dtls1_close_construct_packet,
56 dtls1_handshake_write
57 };
58
dtls1_default_timeout(void)59 long dtls1_default_timeout(void)
60 {
61 /*
62 * 2 hours, the 24 hours mentioned in the DTLSv1 spec is way too long for
63 * http, the cache would over fill
64 */
65 return (60 * 60 * 2);
66 }
67
dtls1_new(SSL * ssl)68 int dtls1_new(SSL *ssl)
69 {
70 DTLS1_STATE *d1;
71 SSL_CONNECTION *s = SSL_CONNECTION_FROM_SSL_ONLY(ssl);
72
73 if (s == NULL)
74 return 0;
75
76 if (!DTLS_RECORD_LAYER_new(&s->rlayer)) {
77 return 0;
78 }
79
80 if (!ssl3_new(ssl))
81 return 0;
82 if ((d1 = OPENSSL_zalloc(sizeof(*d1))) == NULL) {
83 ssl3_free(ssl);
84 return 0;
85 }
86
87 d1->buffered_messages = pqueue_new();
88 d1->sent_messages = pqueue_new();
89
90 if (s->server) {
91 d1->cookie_len = sizeof(s->d1->cookie);
92 }
93
94 d1->link_mtu = 0;
95 d1->mtu = 0;
96
97 if (d1->buffered_messages == NULL || d1->sent_messages == NULL) {
98 pqueue_free(d1->buffered_messages);
99 pqueue_free(d1->sent_messages);
100 OPENSSL_free(d1);
101 ssl3_free(ssl);
102 return 0;
103 }
104
105 s->d1 = d1;
106
107 if (!ssl->method->ssl_clear(ssl))
108 return 0;
109
110 return 1;
111 }
112
dtls1_clear_queues(SSL_CONNECTION * s)113 static void dtls1_clear_queues(SSL_CONNECTION *s)
114 {
115 dtls1_clear_received_buffer(s);
116 dtls1_clear_sent_buffer(s);
117 }
118
dtls1_clear_received_buffer(SSL_CONNECTION * s)119 void dtls1_clear_received_buffer(SSL_CONNECTION *s)
120 {
121 pitem *item = NULL;
122 hm_fragment *frag = NULL;
123
124 while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) {
125 frag = (hm_fragment *)item->data;
126 dtls1_hm_fragment_free(frag);
127 pitem_free(item);
128 }
129 }
130
dtls1_clear_sent_buffer(SSL_CONNECTION * s)131 void dtls1_clear_sent_buffer(SSL_CONNECTION *s)
132 {
133 pitem *item = NULL;
134 hm_fragment *frag = NULL;
135
136 while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) {
137 frag = (hm_fragment *)item->data;
138 dtls1_hm_fragment_free(frag);
139 pitem_free(item);
140 }
141 }
142
143
dtls1_free(SSL * ssl)144 void dtls1_free(SSL *ssl)
145 {
146 SSL_CONNECTION *s = SSL_CONNECTION_FROM_SSL_ONLY(ssl);
147
148 if (s == NULL)
149 return;
150
151 DTLS_RECORD_LAYER_free(&s->rlayer);
152
153 ssl3_free(ssl);
154
155 if (s->d1 != NULL) {
156 dtls1_clear_queues(s);
157 pqueue_free(s->d1->buffered_messages);
158 pqueue_free(s->d1->sent_messages);
159 }
160
161 OPENSSL_free(s->d1);
162 s->d1 = NULL;
163 }
164
dtls1_clear(SSL * ssl)165 int dtls1_clear(SSL *ssl)
166 {
167 pqueue *buffered_messages;
168 pqueue *sent_messages;
169 size_t mtu;
170 size_t link_mtu;
171
172 SSL_CONNECTION *s = SSL_CONNECTION_FROM_SSL_ONLY(ssl);
173
174 if (s == NULL)
175 return 0;
176
177 DTLS_RECORD_LAYER_clear(&s->rlayer);
178
179 if (s->d1) {
180 DTLS_timer_cb timer_cb = s->d1->timer_cb;
181
182 buffered_messages = s->d1->buffered_messages;
183 sent_messages = s->d1->sent_messages;
184 mtu = s->d1->mtu;
185 link_mtu = s->d1->link_mtu;
186
187 dtls1_clear_queues(s);
188
189 memset(s->d1, 0, sizeof(*s->d1));
190
191 /* Restore the timer callback from previous state */
192 s->d1->timer_cb = timer_cb;
193
194 if (s->server) {
195 s->d1->cookie_len = sizeof(s->d1->cookie);
196 }
197
198 if (SSL_get_options(ssl) & SSL_OP_NO_QUERY_MTU) {
199 s->d1->mtu = mtu;
200 s->d1->link_mtu = link_mtu;
201 }
202
203 s->d1->buffered_messages = buffered_messages;
204 s->d1->sent_messages = sent_messages;
205 }
206
207 if (!ssl3_clear(ssl))
208 return 0;
209
210 if (ssl->method->version == DTLS_ANY_VERSION)
211 s->version = DTLS_MAX_VERSION_INTERNAL;
212 #ifndef OPENSSL_NO_DTLS1_METHOD
213 else if (s->options & SSL_OP_CISCO_ANYCONNECT)
214 s->client_version = s->version = DTLS1_BAD_VER;
215 #endif
216 else
217 s->version = ssl->method->version;
218
219 return 1;
220 }
221
dtls1_ctrl(SSL * ssl,int cmd,long larg,void * parg)222 long dtls1_ctrl(SSL *ssl, int cmd, long larg, void *parg)
223 {
224 int ret = 0;
225 SSL_CONNECTION *s = SSL_CONNECTION_FROM_SSL_ONLY(ssl);
226
227 if (s == NULL)
228 return 0;
229
230 switch (cmd) {
231 case DTLS_CTRL_GET_TIMEOUT:
232 if (dtls1_get_timeout(s, (struct timeval *)parg) != NULL) {
233 ret = 1;
234 }
235 break;
236 case DTLS_CTRL_HANDLE_TIMEOUT:
237 ret = dtls1_handle_timeout(s);
238 break;
239 case DTLS_CTRL_SET_LINK_MTU:
240 if (larg < (long)dtls1_link_min_mtu())
241 return 0;
242 s->d1->link_mtu = larg;
243 return 1;
244 case DTLS_CTRL_GET_LINK_MIN_MTU:
245 return (long)dtls1_link_min_mtu();
246 case SSL_CTRL_SET_MTU:
247 /*
248 * We may not have a BIO set yet so can't call dtls1_min_mtu()
249 * We'll have to make do with dtls1_link_min_mtu() and max overhead
250 */
251 if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD)
252 return 0;
253 s->d1->mtu = larg;
254 return larg;
255 default:
256 ret = ssl3_ctrl(ssl, cmd, larg, parg);
257 break;
258 }
259 return ret;
260 }
261
dtls1_start_timer(SSL_CONNECTION * s)262 void dtls1_start_timer(SSL_CONNECTION *s)
263 {
264 unsigned int sec, usec;
265 SSL *ssl = SSL_CONNECTION_GET_SSL(s);
266
267 #ifndef OPENSSL_NO_SCTP
268 /* Disable timer for SCTP */
269 if (BIO_dgram_is_sctp(SSL_get_wbio(ssl))) {
270 memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
271 return;
272 }
273 #endif
274
275 /*
276 * If timer is not set, initialize duration with 1 second or
277 * a user-specified value if the timer callback is installed.
278 */
279 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
280
281 if (s->d1->timer_cb != NULL)
282 s->d1->timeout_duration_us = s->d1->timer_cb(ssl, 0);
283 else
284 s->d1->timeout_duration_us = 1000000;
285 }
286
287 /* Set timeout to current time */
288 get_current_time(&(s->d1->next_timeout));
289
290 /* Add duration to current time */
291
292 sec = s->d1->timeout_duration_us / 1000000;
293 usec = s->d1->timeout_duration_us - (sec * 1000000);
294
295 s->d1->next_timeout.tv_sec += sec;
296 s->d1->next_timeout.tv_usec += usec;
297
298 if (s->d1->next_timeout.tv_usec >= 1000000) {
299 s->d1->next_timeout.tv_sec++;
300 s->d1->next_timeout.tv_usec -= 1000000;
301 }
302
303 BIO_ctrl(SSL_get_rbio(ssl), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
304 &(s->d1->next_timeout));
305 }
306
dtls1_get_timeout(SSL_CONNECTION * s,struct timeval * timeleft)307 struct timeval *dtls1_get_timeout(SSL_CONNECTION *s, struct timeval *timeleft)
308 {
309 struct timeval timenow;
310
311 /* If no timeout is set, just return NULL */
312 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
313 return NULL;
314 }
315
316 /* Get current time */
317 get_current_time(&timenow);
318
319 /* If timer already expired, set remaining time to 0 */
320 if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
321 (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
322 s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
323 memset(timeleft, 0, sizeof(*timeleft));
324 return timeleft;
325 }
326
327 /* Calculate time left until timer expires */
328 memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
329 timeleft->tv_sec -= timenow.tv_sec;
330 timeleft->tv_usec -= timenow.tv_usec;
331 if (timeleft->tv_usec < 0) {
332 timeleft->tv_sec--;
333 timeleft->tv_usec += 1000000;
334 }
335
336 /*
337 * If remaining time is less than 15 ms, set it to 0 to prevent issues
338 * because of small divergences with socket timeouts.
339 */
340 if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
341 memset(timeleft, 0, sizeof(*timeleft));
342 }
343
344 return timeleft;
345 }
346
dtls1_is_timer_expired(SSL_CONNECTION * s)347 int dtls1_is_timer_expired(SSL_CONNECTION *s)
348 {
349 struct timeval timeleft;
350
351 /* Get time left until timeout, return false if no timer running */
352 if (dtls1_get_timeout(s, &timeleft) == NULL) {
353 return 0;
354 }
355
356 /* Return false if timer is not expired yet */
357 if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
358 return 0;
359 }
360
361 /* Timer expired, so return true */
362 return 1;
363 }
364
dtls1_double_timeout(SSL_CONNECTION * s)365 static void dtls1_double_timeout(SSL_CONNECTION *s)
366 {
367 s->d1->timeout_duration_us *= 2;
368 if (s->d1->timeout_duration_us > 60000000)
369 s->d1->timeout_duration_us = 60000000;
370 }
371
dtls1_stop_timer(SSL_CONNECTION * s)372 void dtls1_stop_timer(SSL_CONNECTION *s)
373 {
374 /* Reset everything */
375 s->d1->timeout_num_alerts = 0;
376 memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
377 s->d1->timeout_duration_us = 1000000;
378 BIO_ctrl(s->rbio, BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
379 &(s->d1->next_timeout));
380 /* Clear retransmission buffer */
381 dtls1_clear_sent_buffer(s);
382 }
383
dtls1_check_timeout_num(SSL_CONNECTION * s)384 int dtls1_check_timeout_num(SSL_CONNECTION *s)
385 {
386 size_t mtu;
387 SSL *ssl = SSL_CONNECTION_GET_SSL(s);
388
389 s->d1->timeout_num_alerts++;
390
391 /* Reduce MTU after 2 unsuccessful retransmissions */
392 if (s->d1->timeout_num_alerts > 2
393 && !(SSL_get_options(ssl) & SSL_OP_NO_QUERY_MTU)) {
394 mtu =
395 BIO_ctrl(SSL_get_wbio(ssl), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL);
396 if (mtu < s->d1->mtu)
397 s->d1->mtu = mtu;
398 }
399
400 if (s->d1->timeout_num_alerts > DTLS1_TMO_ALERT_COUNT) {
401 /* fail the connection, enough alerts have been sent */
402 SSLfatal(s, SSL_AD_NO_ALERT, SSL_R_READ_TIMEOUT_EXPIRED);
403 return -1;
404 }
405
406 return 0;
407 }
408
dtls1_handle_timeout(SSL_CONNECTION * s)409 int dtls1_handle_timeout(SSL_CONNECTION *s)
410 {
411 /* if no timer is expired, don't do anything */
412 if (!dtls1_is_timer_expired(s)) {
413 return 0;
414 }
415
416 if (s->d1->timer_cb != NULL)
417 s->d1->timeout_duration_us = s->d1->timer_cb(SSL_CONNECTION_GET_SSL(s),
418 s->d1->timeout_duration_us);
419 else
420 dtls1_double_timeout(s);
421
422 if (dtls1_check_timeout_num(s) < 0) {
423 /* SSLfatal() already called */
424 return -1;
425 }
426
427 dtls1_start_timer(s);
428 /* Calls SSLfatal() if required */
429 return dtls1_retransmit_buffered_messages(s);
430 }
431
get_current_time(struct timeval * t)432 static void get_current_time(struct timeval *t)
433 {
434 ossl_time_time_to_timeval(ossl_time_now(), t);
435 }
436
437 #define LISTEN_SUCCESS 2
438 #define LISTEN_SEND_VERIFY_REQUEST 1
439
440 #ifndef OPENSSL_NO_SOCK
DTLSv1_listen(SSL * ssl,BIO_ADDR * client)441 int DTLSv1_listen(SSL *ssl, BIO_ADDR *client)
442 {
443 int next, n, ret = 0;
444 unsigned char cookie[DTLS1_COOKIE_LENGTH];
445 unsigned char seq[SEQ_NUM_SIZE];
446 const unsigned char *data;
447 unsigned char *buf = NULL, *wbuf;
448 size_t fragoff, fraglen, msglen;
449 unsigned int rectype, versmajor, msgseq, msgtype, clientvers, cookielen;
450 BIO *rbio, *wbio;
451 BIO_ADDR *tmpclient = NULL;
452 PACKET pkt, msgpkt, msgpayload, session, cookiepkt;
453 SSL_CONNECTION *s = SSL_CONNECTION_FROM_SSL_ONLY(ssl);
454
455 if (s == NULL)
456 return -1;
457
458 if (s->handshake_func == NULL) {
459 /* Not properly initialized yet */
460 SSL_set_accept_state(ssl);
461 }
462
463 /* Ensure there is no state left over from a previous invocation */
464 if (!SSL_clear(ssl))
465 return -1;
466
467 ERR_clear_error();
468
469 rbio = SSL_get_rbio(ssl);
470 wbio = SSL_get_wbio(ssl);
471
472 if (!rbio || !wbio) {
473 ERR_raise(ERR_LIB_SSL, SSL_R_BIO_NOT_SET);
474 return -1;
475 }
476
477 /*
478 * Note: This check deliberately excludes DTLS1_BAD_VER because that version
479 * requires the MAC to be calculated *including* the first ClientHello
480 * (without the cookie). Since DTLSv1_listen is stateless that cannot be
481 * supported. DTLS1_BAD_VER must use cookies in a stateful manner (e.g. via
482 * SSL_accept)
483 */
484 if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
485 ERR_raise(ERR_LIB_SSL, SSL_R_UNSUPPORTED_SSL_VERSION);
486 return -1;
487 }
488
489 if (!ssl3_setup_buffers(s)) {
490 /* ERR_raise() already called */
491 return -1;
492 }
493 buf = OPENSSL_malloc(DTLS1_RT_HEADER_LENGTH + SSL3_RT_MAX_PLAIN_LENGTH);
494 if (buf == NULL) {
495 ERR_raise(ERR_LIB_SSL, ERR_R_MALLOC_FAILURE);
496 return -1;
497 }
498 wbuf = RECORD_LAYER_get_wbuf(&s->rlayer)[0].buf;
499
500 do {
501 /* Get a packet */
502
503 clear_sys_error();
504 n = BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH
505 + DTLS1_RT_HEADER_LENGTH);
506 if (n <= 0) {
507 if (BIO_should_retry(rbio)) {
508 /* Non-blocking IO */
509 goto end;
510 }
511 ret = -1;
512 goto end;
513 }
514
515 if (!PACKET_buf_init(&pkt, buf, n)) {
516 ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR);
517 ret = -1;
518 goto end;
519 }
520
521 /*
522 * Parse the received record. If there are any problems with it we just
523 * dump it - with no alert. RFC6347 says this "Unlike TLS, DTLS is
524 * resilient in the face of invalid records (e.g., invalid formatting,
525 * length, MAC, etc.). In general, invalid records SHOULD be silently
526 * discarded, thus preserving the association; however, an error MAY be
527 * logged for diagnostic purposes."
528 */
529
530 /* this packet contained a partial record, dump it */
531 if (n < DTLS1_RT_HEADER_LENGTH) {
532 ERR_raise(ERR_LIB_SSL, SSL_R_RECORD_TOO_SMALL);
533 goto end;
534 }
535
536 if (s->msg_callback)
537 s->msg_callback(0, 0, SSL3_RT_HEADER, buf,
538 DTLS1_RT_HEADER_LENGTH, ssl, s->msg_callback_arg);
539
540 /* Get the record header */
541 if (!PACKET_get_1(&pkt, &rectype)
542 || !PACKET_get_1(&pkt, &versmajor)) {
543 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
544 goto end;
545 }
546
547 if (rectype != SSL3_RT_HANDSHAKE) {
548 ERR_raise(ERR_LIB_SSL, SSL_R_UNEXPECTED_MESSAGE);
549 goto end;
550 }
551
552 /*
553 * Check record version number. We only check that the major version is
554 * the same.
555 */
556 if (versmajor != DTLS1_VERSION_MAJOR) {
557 ERR_raise(ERR_LIB_SSL, SSL_R_BAD_PROTOCOL_VERSION_NUMBER);
558 goto end;
559 }
560
561 if (!PACKET_forward(&pkt, 1)
562 /* Save the sequence number: 64 bits, with top 2 bytes = epoch */
563 || !PACKET_copy_bytes(&pkt, seq, SEQ_NUM_SIZE)
564 || !PACKET_get_length_prefixed_2(&pkt, &msgpkt)) {
565 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
566 goto end;
567 }
568 /*
569 * We allow data remaining at the end of the packet because there could
570 * be a second record (but we ignore it)
571 */
572
573 /* This is an initial ClientHello so the epoch has to be 0 */
574 if (seq[0] != 0 || seq[1] != 0) {
575 ERR_raise(ERR_LIB_SSL, SSL_R_UNEXPECTED_MESSAGE);
576 goto end;
577 }
578
579 /* Get a pointer to the raw message for the later callback */
580 data = PACKET_data(&msgpkt);
581
582 /* Finished processing the record header, now process the message */
583 if (!PACKET_get_1(&msgpkt, &msgtype)
584 || !PACKET_get_net_3_len(&msgpkt, &msglen)
585 || !PACKET_get_net_2(&msgpkt, &msgseq)
586 || !PACKET_get_net_3_len(&msgpkt, &fragoff)
587 || !PACKET_get_net_3_len(&msgpkt, &fraglen)
588 || !PACKET_get_sub_packet(&msgpkt, &msgpayload, fraglen)
589 || PACKET_remaining(&msgpkt) != 0) {
590 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
591 goto end;
592 }
593
594 if (msgtype != SSL3_MT_CLIENT_HELLO) {
595 ERR_raise(ERR_LIB_SSL, SSL_R_UNEXPECTED_MESSAGE);
596 goto end;
597 }
598
599 /* Message sequence number can only be 0 or 1 */
600 if (msgseq > 2) {
601 ERR_raise(ERR_LIB_SSL, SSL_R_INVALID_SEQUENCE_NUMBER);
602 goto end;
603 }
604
605 /*
606 * We don't support fragment reassembly for ClientHellos whilst
607 * listening because that would require server side state (which is
608 * against the whole point of the ClientHello/HelloVerifyRequest
609 * mechanism). Instead we only look at the first ClientHello fragment
610 * and require that the cookie must be contained within it.
611 */
612 if (fragoff != 0 || fraglen > msglen) {
613 /* Non initial ClientHello fragment (or bad fragment) */
614 ERR_raise(ERR_LIB_SSL, SSL_R_FRAGMENTED_CLIENT_HELLO);
615 goto end;
616 }
617
618 if (s->msg_callback)
619 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, data,
620 fraglen + DTLS1_HM_HEADER_LENGTH, ssl,
621 s->msg_callback_arg);
622
623 if (!PACKET_get_net_2(&msgpayload, &clientvers)) {
624 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
625 goto end;
626 }
627
628 /*
629 * Verify client version is supported
630 */
631 if (DTLS_VERSION_LT(clientvers, (unsigned int)ssl->method->version) &&
632 ssl->method->version != DTLS_ANY_VERSION) {
633 ERR_raise(ERR_LIB_SSL, SSL_R_WRONG_VERSION_NUMBER);
634 goto end;
635 }
636
637 if (!PACKET_forward(&msgpayload, SSL3_RANDOM_SIZE)
638 || !PACKET_get_length_prefixed_1(&msgpayload, &session)
639 || !PACKET_get_length_prefixed_1(&msgpayload, &cookiepkt)) {
640 /*
641 * Could be malformed or the cookie does not fit within the initial
642 * ClientHello fragment. Either way we can't handle it.
643 */
644 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
645 goto end;
646 }
647
648 /*
649 * Check if we have a cookie or not. If not we need to send a
650 * HelloVerifyRequest.
651 */
652 if (PACKET_remaining(&cookiepkt) == 0) {
653 next = LISTEN_SEND_VERIFY_REQUEST;
654 } else {
655 /*
656 * We have a cookie, so lets check it.
657 */
658 if (ssl->ctx->app_verify_cookie_cb == NULL) {
659 ERR_raise(ERR_LIB_SSL, SSL_R_NO_VERIFY_COOKIE_CALLBACK);
660 /* This is fatal */
661 ret = -1;
662 goto end;
663 }
664 if (ssl->ctx->app_verify_cookie_cb(ssl, PACKET_data(&cookiepkt),
665 (unsigned int)PACKET_remaining(&cookiepkt)) == 0) {
666 /*
667 * We treat invalid cookies in the same was as no cookie as
668 * per RFC6347
669 */
670 next = LISTEN_SEND_VERIFY_REQUEST;
671 } else {
672 /* Cookie verification succeeded */
673 next = LISTEN_SUCCESS;
674 }
675 }
676
677 if (next == LISTEN_SEND_VERIFY_REQUEST) {
678 WPACKET wpkt;
679 unsigned int version;
680 size_t wreclen;
681
682 /*
683 * There was no cookie in the ClientHello so we need to send a
684 * HelloVerifyRequest. If this fails we do not worry about trying
685 * to resend, we just drop it.
686 */
687
688 /* Generate the cookie */
689 if (ssl->ctx->app_gen_cookie_cb == NULL ||
690 ssl->ctx->app_gen_cookie_cb(ssl, cookie, &cookielen) == 0 ||
691 cookielen > 255) {
692 ERR_raise(ERR_LIB_SSL, SSL_R_COOKIE_GEN_CALLBACK_FAILURE);
693 /* This is fatal */
694 ret = -1;
695 goto end;
696 }
697
698 /*
699 * Special case: for hello verify request, client version 1.0 and we
700 * haven't decided which version to use yet send back using version
701 * 1.0 header: otherwise some clients will ignore it.
702 */
703 version = (ssl->method->version == DTLS_ANY_VERSION) ? DTLS1_VERSION
704 : s->version;
705
706 /* Construct the record and message headers */
707 if (!WPACKET_init_static_len(&wpkt,
708 wbuf,
709 ssl_get_max_send_fragment(s)
710 + DTLS1_RT_HEADER_LENGTH,
711 0)
712 || !WPACKET_put_bytes_u8(&wpkt, SSL3_RT_HANDSHAKE)
713 || !WPACKET_put_bytes_u16(&wpkt, version)
714 /*
715 * Record sequence number is always the same as in the
716 * received ClientHello
717 */
718 || !WPACKET_memcpy(&wpkt, seq, SEQ_NUM_SIZE)
719 /* End of record, start sub packet for message */
720 || !WPACKET_start_sub_packet_u16(&wpkt)
721 /* Message type */
722 || !WPACKET_put_bytes_u8(&wpkt,
723 DTLS1_MT_HELLO_VERIFY_REQUEST)
724 /*
725 * Message length - doesn't follow normal TLS convention:
726 * the length isn't the last thing in the message header.
727 * We'll need to fill this in later when we know the
728 * length. Set it to zero for now
729 */
730 || !WPACKET_put_bytes_u24(&wpkt, 0)
731 /*
732 * Message sequence number is always 0 for a
733 * HelloVerifyRequest
734 */
735 || !WPACKET_put_bytes_u16(&wpkt, 0)
736 /*
737 * We never fragment a HelloVerifyRequest, so fragment
738 * offset is 0
739 */
740 || !WPACKET_put_bytes_u24(&wpkt, 0)
741 /*
742 * Fragment length is the same as message length, but
743 * this *is* the last thing in the message header so we
744 * can just start a sub-packet. No need to come back
745 * later for this one.
746 */
747 || !WPACKET_start_sub_packet_u24(&wpkt)
748 /* Create the actual HelloVerifyRequest body */
749 || !dtls_raw_hello_verify_request(&wpkt, cookie, cookielen)
750 /* Close message body */
751 || !WPACKET_close(&wpkt)
752 /* Close record body */
753 || !WPACKET_close(&wpkt)
754 || !WPACKET_get_total_written(&wpkt, &wreclen)
755 || !WPACKET_finish(&wpkt)) {
756 ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR);
757 WPACKET_cleanup(&wpkt);
758 /* This is fatal */
759 ret = -1;
760 goto end;
761 }
762
763 /*
764 * Fix up the message len in the message header. Its the same as the
765 * fragment len which has been filled in by WPACKET, so just copy
766 * that. Destination for the message len is after the record header
767 * plus one byte for the message content type. The source is the
768 * last 3 bytes of the message header
769 */
770 memcpy(&wbuf[DTLS1_RT_HEADER_LENGTH + 1],
771 &wbuf[DTLS1_RT_HEADER_LENGTH + DTLS1_HM_HEADER_LENGTH - 3],
772 3);
773
774 if (s->msg_callback)
775 s->msg_callback(1, 0, SSL3_RT_HEADER, buf,
776 DTLS1_RT_HEADER_LENGTH, ssl,
777 s->msg_callback_arg);
778
779 if ((tmpclient = BIO_ADDR_new()) == NULL) {
780 ERR_raise(ERR_LIB_SSL, ERR_R_MALLOC_FAILURE);
781 goto end;
782 }
783
784 /*
785 * This is unnecessary if rbio and wbio are one and the same - but
786 * maybe they're not. We ignore errors here - some BIOs do not
787 * support this.
788 */
789 if (BIO_dgram_get_peer(rbio, tmpclient) > 0) {
790 (void)BIO_dgram_set_peer(wbio, tmpclient);
791 }
792 BIO_ADDR_free(tmpclient);
793 tmpclient = NULL;
794
795 if (BIO_write(wbio, wbuf, wreclen) < (int)wreclen) {
796 if (BIO_should_retry(wbio)) {
797 /*
798 * Non-blocking IO...but we're stateless, so we're just
799 * going to drop this packet.
800 */
801 goto end;
802 }
803 ret = -1;
804 goto end;
805 }
806
807 if (BIO_flush(wbio) <= 0) {
808 if (BIO_should_retry(wbio)) {
809 /*
810 * Non-blocking IO...but we're stateless, so we're just
811 * going to drop this packet.
812 */
813 goto end;
814 }
815 ret = -1;
816 goto end;
817 }
818 }
819 } while (next != LISTEN_SUCCESS);
820
821 /*
822 * Set expected sequence numbers to continue the handshake.
823 */
824 s->d1->handshake_read_seq = 1;
825 s->d1->handshake_write_seq = 1;
826 s->d1->next_handshake_write_seq = 1;
827 DTLS_RECORD_LAYER_set_write_sequence(&s->rlayer, seq);
828
829 /*
830 * We are doing cookie exchange, so make sure we set that option in the
831 * SSL object
832 */
833 SSL_set_options(ssl, SSL_OP_COOKIE_EXCHANGE);
834
835 /*
836 * Tell the state machine that we've done the initial hello verify
837 * exchange
838 */
839 ossl_statem_set_hello_verify_done(s);
840
841 /*
842 * Some BIOs may not support this. If we fail we clear the client address
843 */
844 if (BIO_dgram_get_peer(rbio, client) <= 0)
845 BIO_ADDR_clear(client);
846
847 /* Buffer the record for use by the record layer */
848 if (BIO_write(s->rlayer.rrlnext, buf, n) != n) {
849 ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR);
850 ret = -1;
851 goto end;
852 }
853
854 /*
855 * Reset the record layer - but this time we can use the record we just
856 * buffered in s->rlayer.rrlnext
857 */
858 if (!ssl_set_new_record_layer(s,
859 DTLS_ANY_VERSION,
860 OSSL_RECORD_DIRECTION_READ,
861 OSSL_RECORD_PROTECTION_LEVEL_NONE,
862 NULL, 0, NULL, 0, NULL, 0, NULL, 0,
863 NID_undef, NULL, NULL)) {
864 /* SSLfatal already called */
865 ret = -1;
866 goto end;
867 }
868
869 ret = 1;
870 end:
871 BIO_ADDR_free(tmpclient);
872 OPENSSL_free(buf);
873 return ret;
874 }
875 #endif
876
dtls1_handshake_write(SSL_CONNECTION * s)877 static int dtls1_handshake_write(SSL_CONNECTION *s)
878 {
879 return dtls1_do_write(s, SSL3_RT_HANDSHAKE);
880 }
881
dtls1_shutdown(SSL * s)882 int dtls1_shutdown(SSL *s)
883 {
884 int ret;
885 #ifndef OPENSSL_NO_SCTP
886 BIO *wbio;
887 SSL_CONNECTION *sc = SSL_CONNECTION_FROM_SSL_ONLY(s);
888
889 if (s == NULL)
890 return -1;
891
892 wbio = SSL_get_wbio(s);
893 if (wbio != NULL && BIO_dgram_is_sctp(wbio) &&
894 !(sc->shutdown & SSL_SENT_SHUTDOWN)) {
895 ret = BIO_dgram_sctp_wait_for_dry(wbio);
896 if (ret < 0)
897 return -1;
898
899 if (ret == 0)
900 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1,
901 NULL);
902 }
903 #endif
904 ret = ssl3_shutdown(s);
905 #ifndef OPENSSL_NO_SCTP
906 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
907 #endif
908 return ret;
909 }
910
dtls1_query_mtu(SSL_CONNECTION * s)911 int dtls1_query_mtu(SSL_CONNECTION *s)
912 {
913 SSL *ssl = SSL_CONNECTION_GET_SSL(s);
914
915 if (s->d1->link_mtu) {
916 s->d1->mtu =
917 s->d1->link_mtu - BIO_dgram_get_mtu_overhead(SSL_get_wbio(ssl));
918 s->d1->link_mtu = 0;
919 }
920
921 /* AHA! Figure out the MTU, and stick to the right size */
922 if (s->d1->mtu < dtls1_min_mtu(s)) {
923 if (!(SSL_get_options(ssl) & SSL_OP_NO_QUERY_MTU)) {
924 s->d1->mtu =
925 BIO_ctrl(SSL_get_wbio(ssl), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
926
927 /*
928 * I've seen the kernel return bogus numbers when it doesn't know
929 * (initial write), so just make sure we have a reasonable number
930 */
931 if (s->d1->mtu < dtls1_min_mtu(s)) {
932 /* Set to min mtu */
933 s->d1->mtu = dtls1_min_mtu(s);
934 BIO_ctrl(SSL_get_wbio(ssl), BIO_CTRL_DGRAM_SET_MTU,
935 (long)s->d1->mtu, NULL);
936 }
937 } else
938 return 0;
939 }
940 return 1;
941 }
942
dtls1_link_min_mtu(void)943 static size_t dtls1_link_min_mtu(void)
944 {
945 return (g_probable_mtu[(sizeof(g_probable_mtu) /
946 sizeof(g_probable_mtu[0])) - 1]);
947 }
948
dtls1_min_mtu(SSL_CONNECTION * s)949 size_t dtls1_min_mtu(SSL_CONNECTION *s)
950 {
951 SSL *ssl = SSL_CONNECTION_GET_SSL(s);
952
953 return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(ssl));
954 }
955
DTLS_get_data_mtu(const SSL * ssl)956 size_t DTLS_get_data_mtu(const SSL *ssl)
957 {
958 size_t mac_overhead, int_overhead, blocksize, ext_overhead;
959 const SSL_CIPHER *ciph = SSL_get_current_cipher(ssl);
960 size_t mtu;
961 const SSL_CONNECTION *s = SSL_CONNECTION_FROM_CONST_SSL_ONLY(ssl);
962
963 if (s == NULL)
964 return 0;
965
966 mtu = s->d1->mtu;
967
968 if (ciph == NULL)
969 return 0;
970
971 if (!ssl_cipher_get_overhead(ciph, &mac_overhead, &int_overhead,
972 &blocksize, &ext_overhead))
973 return 0;
974
975 if (SSL_READ_ETM(s))
976 ext_overhead += mac_overhead;
977 else
978 int_overhead += mac_overhead;
979
980 /* Subtract external overhead (e.g. IV/nonce, separate MAC) */
981 if (ext_overhead + DTLS1_RT_HEADER_LENGTH >= mtu)
982 return 0;
983 mtu -= ext_overhead + DTLS1_RT_HEADER_LENGTH;
984
985 /* Round encrypted payload down to cipher block size (for CBC etc.)
986 * No check for overflow since 'mtu % blocksize' cannot exceed mtu. */
987 if (blocksize)
988 mtu -= (mtu % blocksize);
989
990 /* Subtract internal overhead (e.g. CBC padding len byte) */
991 if (int_overhead >= mtu)
992 return 0;
993 mtu -= int_overhead;
994
995 return mtu;
996 }
997
DTLS_set_timer_cb(SSL * ssl,DTLS_timer_cb cb)998 void DTLS_set_timer_cb(SSL *ssl, DTLS_timer_cb cb)
999 {
1000 SSL_CONNECTION *s = SSL_CONNECTION_FROM_SSL_ONLY(ssl);
1001
1002 if (s == NULL)
1003 return;
1004
1005 s->d1->timer_cb = cb;
1006 }
1007
