2 * DTLS implementation written by Nagendra Modadugu
3 * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
5 /* ====================================================================
6 * Copyright (c) 1999-2005 The OpenSSL Project. All rights reserved.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
20 * 3. All advertising materials mentioning features or use of this
21 * software must display the following acknowledgment:
22 * "This product includes software developed by the OpenSSL Project
23 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
25 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26 * endorse or promote products derived from this software without
27 * prior written permission. For written permission, please contact
28 * openssl-core@OpenSSL.org.
30 * 5. Products derived from this software may not be called "OpenSSL"
31 * nor may "OpenSSL" appear in their names without prior written
32 * permission of the OpenSSL Project.
34 * 6. Redistributions of any form whatsoever must retain the following
36 * "This product includes software developed by the OpenSSL Project
37 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
39 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
43 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50 * OF THE POSSIBILITY OF SUCH DAMAGE.
51 * ====================================================================
53 * This product includes cryptographic software written by Eric Young
54 * (eay@cryptsoft.com). This product includes software written by Tim
55 * Hudson (tjh@cryptsoft.com).
61 #include <openssl/objects.h>
62 #include <openssl/rand.h>
65 #if defined(OPENSSL_SYS_VMS)
66 # include <sys/timeb.h>
67 #elif defined(OPENSSL_SYS_NETWARE) && !defined(_WINSOCK2API_)
68 # include <sys/timeval.h>
69 #elif defined(OPENSSL_SYS_VXWORKS)
70 # include <sys/times.h>
71 #elif !defined(OPENSSL_SYS_WIN32)
72 # include <sys/time.h>
75 static void get_current_time(struct timeval *t);
76 static int dtls1_set_handshake_header(SSL *s, int type, unsigned long len);
77 static int dtls1_handshake_write(SSL *s);
78 static unsigned int dtls1_link_min_mtu(void);
80 /* XDTLS: figure out the right values */
81 static const unsigned int g_probable_mtu[] = { 1500, 512, 256 };
83 const SSL3_ENC_METHOD DTLSv1_enc_data = {
87 tls1_generate_master_secret,
88 tls1_change_cipher_state,
89 tls1_final_finish_mac,
90 TLS1_FINISH_MAC_LENGTH,
91 TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
92 TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
94 tls1_export_keying_material,
95 SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV,
96 DTLS1_HM_HEADER_LENGTH,
97 dtls1_set_handshake_header,
101 const SSL3_ENC_METHOD DTLSv1_2_enc_data = {
104 tls1_setup_key_block,
105 tls1_generate_master_secret,
106 tls1_change_cipher_state,
107 tls1_final_finish_mac,
108 TLS1_FINISH_MAC_LENGTH,
109 TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
110 TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
112 tls1_export_keying_material,
113 SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV | SSL_ENC_FLAG_SIGALGS
114 | SSL_ENC_FLAG_SHA256_PRF | SSL_ENC_FLAG_TLS1_2_CIPHERS,
115 DTLS1_HM_HEADER_LENGTH,
116 dtls1_set_handshake_header,
117 dtls1_handshake_write
120 long dtls1_default_timeout(void)
123 * 2 hours, the 24 hours mentioned in the DTLSv1 spec is way too long for
124 * http, the cache would over fill
126 return (60 * 60 * 2);
129 int dtls1_new(SSL *s)
133 if (!DTLS_RECORD_LAYER_new(&s->rlayer)) {
139 if ((d1 = OPENSSL_zalloc(sizeof(*d1))) == NULL) {
144 d1->buffered_messages = pqueue_new();
145 d1->sent_messages = pqueue_new();
148 d1->cookie_len = sizeof(s->d1->cookie);
154 if (d1->buffered_messages == NULL || d1->sent_messages == NULL) {
155 pqueue_free(d1->buffered_messages);
156 pqueue_free(d1->sent_messages);
163 s->method->ssl_clear(s);
167 static void dtls1_clear_queues(SSL *s)
170 hm_fragment *frag = NULL;
172 while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) {
173 frag = (hm_fragment *)item->data;
174 dtls1_hm_fragment_free(frag);
178 while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) {
179 frag = (hm_fragment *)item->data;
180 dtls1_hm_fragment_free(frag);
185 void dtls1_free(SSL *s)
187 DTLS_RECORD_LAYER_free(&s->rlayer);
191 dtls1_clear_queues(s);
193 pqueue_free(s->d1->buffered_messages);
194 pqueue_free(s->d1->sent_messages);
200 void dtls1_clear(SSL *s)
202 pqueue *buffered_messages;
203 pqueue *sent_messages;
205 unsigned int link_mtu;
207 DTLS_RECORD_LAYER_clear(&s->rlayer);
210 buffered_messages = s->d1->buffered_messages;
211 sent_messages = s->d1->sent_messages;
213 link_mtu = s->d1->link_mtu;
215 dtls1_clear_queues(s);
217 memset(s->d1, 0, sizeof(*s->d1));
220 s->d1->cookie_len = sizeof(s->d1->cookie);
223 if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) {
225 s->d1->link_mtu = link_mtu;
228 s->d1->buffered_messages = buffered_messages;
229 s->d1->sent_messages = sent_messages;
233 if (s->options & SSL_OP_CISCO_ANYCONNECT)
234 s->client_version = s->version = DTLS1_BAD_VER;
235 else if (s->method->version == DTLS_ANY_VERSION)
236 s->version = DTLS_MAX_VERSION;
238 s->version = s->method->version;
241 long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
246 case DTLS_CTRL_GET_TIMEOUT:
247 if (dtls1_get_timeout(s, (struct timeval *)parg) != NULL) {
251 case DTLS_CTRL_HANDLE_TIMEOUT:
252 ret = dtls1_handle_timeout(s);
254 case DTLS_CTRL_SET_LINK_MTU:
255 if (larg < (long)dtls1_link_min_mtu())
257 s->d1->link_mtu = larg;
259 case DTLS_CTRL_GET_LINK_MIN_MTU:
260 return (long)dtls1_link_min_mtu();
261 case SSL_CTRL_SET_MTU:
263 * We may not have a BIO set yet so can't call dtls1_min_mtu()
264 * We'll have to make do with dtls1_link_min_mtu() and max overhead
266 if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD)
271 ret = ssl3_ctrl(s, cmd, larg, parg);
278 * As it's impossible to use stream ciphers in "datagram" mode, this
279 * simple filter is designed to disengage them in DTLS. Unfortunately
280 * there is no universal way to identify stream SSL_CIPHER, so we have
281 * to explicitly list their SSL_* codes. Currently RC4 is the only one
282 * available, but if new ones emerge, they will have to be added...
284 const SSL_CIPHER *dtls1_get_cipher(unsigned int u)
286 const SSL_CIPHER *ciph = ssl3_get_cipher(u);
289 if (ciph->algorithm_enc == SSL_RC4)
296 void dtls1_start_timer(SSL *s)
298 #ifndef OPENSSL_NO_SCTP
299 /* Disable timer for SCTP */
300 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
301 memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
306 /* If timer is not set, initialize duration with 1 second */
307 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
308 s->d1->timeout_duration = 1;
311 /* Set timeout to current time */
312 get_current_time(&(s->d1->next_timeout));
314 /* Add duration to current time */
315 s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
316 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
317 &(s->d1->next_timeout));
320 struct timeval *dtls1_get_timeout(SSL *s, struct timeval *timeleft)
322 struct timeval timenow;
324 /* If no timeout is set, just return NULL */
325 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
329 /* Get current time */
330 get_current_time(&timenow);
332 /* If timer already expired, set remaining time to 0 */
333 if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
334 (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
335 s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
336 memset(timeleft, 0, sizeof(*timeleft));
340 /* Calculate time left until timer expires */
341 memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
342 timeleft->tv_sec -= timenow.tv_sec;
343 timeleft->tv_usec -= timenow.tv_usec;
344 if (timeleft->tv_usec < 0) {
346 timeleft->tv_usec += 1000000;
350 * If remaining time is less than 15 ms, set it to 0 to prevent issues
351 * because of small devergences with socket timeouts.
353 if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
354 memset(timeleft, 0, sizeof(*timeleft));
360 int dtls1_is_timer_expired(SSL *s)
362 struct timeval timeleft;
364 /* Get time left until timeout, return false if no timer running */
365 if (dtls1_get_timeout(s, &timeleft) == NULL) {
369 /* Return false if timer is not expired yet */
370 if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
374 /* Timer expired, so return true */
378 void dtls1_double_timeout(SSL *s)
380 s->d1->timeout_duration *= 2;
381 if (s->d1->timeout_duration > 60)
382 s->d1->timeout_duration = 60;
383 dtls1_start_timer(s);
386 void dtls1_stop_timer(SSL *s)
388 /* Reset everything */
389 memset(&s->d1->timeout, 0, sizeof(s->d1->timeout));
390 memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
391 s->d1->timeout_duration = 1;
392 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
393 &(s->d1->next_timeout));
394 /* Clear retransmission buffer */
395 dtls1_clear_record_buffer(s);
398 int dtls1_check_timeout_num(SSL *s)
402 s->d1->timeout.num_alerts++;
404 /* Reduce MTU after 2 unsuccessful retransmissions */
405 if (s->d1->timeout.num_alerts > 2
406 && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
408 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0,
410 if (mtu < s->d1->mtu)
414 if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) {
415 /* fail the connection, enough alerts have been sent */
416 SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM, SSL_R_READ_TIMEOUT_EXPIRED);
423 int dtls1_handle_timeout(SSL *s)
425 /* if no timer is expired, don't do anything */
426 if (!dtls1_is_timer_expired(s)) {
430 dtls1_double_timeout(s);
432 if (dtls1_check_timeout_num(s) < 0)
435 s->d1->timeout.read_timeouts++;
436 if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) {
437 s->d1->timeout.read_timeouts = 1;
439 #ifndef OPENSSL_NO_HEARTBEATS
440 if (s->tlsext_hb_pending) {
441 s->tlsext_hb_pending = 0;
442 return dtls1_heartbeat(s);
446 dtls1_start_timer(s);
447 return dtls1_retransmit_buffered_messages(s);
450 static void get_current_time(struct timeval *t)
460 SystemTimeToFileTime(&st, &now.ft);
462 now.ul -= 116444736000000000ULL;
464 now.ul -= 116444736000000000UI64; /* re-bias to 1/1/1970 */
466 t->tv_sec = (long)(now.ul / 10000000);
467 t->tv_usec = ((int)(now.ul % 10000000)) / 10;
468 #elif defined(OPENSSL_SYS_VMS)
471 t->tv_sec = (long)tb.time;
472 t->tv_usec = (long)tb.millitm * 1000;
474 gettimeofday(t, NULL);
479 #define LISTEN_SUCCESS 2
480 #define LISTEN_SEND_VERIFY_REQUEST 1
483 int DTLSv1_listen(SSL *s, BIO_ADDR *client)
485 int next, n, ret = 0, clearpkt = 0;
486 unsigned char cookie[DTLS1_COOKIE_LENGTH];
487 unsigned char seq[SEQ_NUM_SIZE];
488 const unsigned char *data;
489 unsigned char *p, *buf;
490 unsigned long reclen, fragoff, fraglen, msglen;
491 unsigned int rectype, versmajor, msgseq, msgtype, clientvers, cookielen;
494 BIO_ADDR *tmpclient = NULL;
495 PACKET pkt, msgpkt, msgpayload, session, cookiepkt;
497 /* Ensure there is no state left over from a previous invocation */
503 rbio = SSL_get_rbio(s);
504 wbio = SSL_get_wbio(s);
507 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_BIO_NOT_SET);
512 * We only peek at incoming ClientHello's until we're sure we are going to
513 * to respond with a HelloVerifyRequest. If its a ClientHello with a valid
514 * cookie then we leave it in the BIO for accept to handle.
516 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL);
519 * Note: This check deliberately excludes DTLS1_BAD_VER because that version
520 * requires the MAC to be calculated *including* the first ClientHello
521 * (without the cookie). Since DTLSv1_listen is stateless that cannot be
522 * supported. DTLS1_BAD_VER must use cookies in a stateful manner (e.g. via
525 if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
526 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNSUPPORTED_SSL_VERSION);
530 if (s->init_buf == NULL) {
531 if ((bufm = BUF_MEM_new()) == NULL) {
532 SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE);
536 if (!BUF_MEM_grow(bufm, SSL3_RT_MAX_PLAIN_LENGTH)) {
538 SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE);
543 buf = (unsigned char *)s->init_buf->data;
550 * Technically a ClientHello could be SSL3_RT_MAX_PLAIN_LENGTH
551 * + DTLS1_RT_HEADER_LENGTH bytes long. Normally init_buf does not store
552 * the record header as well, but we do here. We've set up init_buf to
553 * be the standard size for simplicity. In practice we shouldn't ever
554 * receive a ClientHello as long as this. If we do it will get dropped
555 * in the record length check below.
557 n = BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
560 if(BIO_should_retry(rbio)) {
561 /* Non-blocking IO */
567 /* If we hit any problems we need to clear this packet from the BIO */
570 if (!PACKET_buf_init(&pkt, buf, n)) {
571 SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_INTERNAL_ERROR);
576 * Parse the received record. If there are any problems with it we just
577 * dump it - with no alert. RFC6347 says this "Unlike TLS, DTLS is
578 * resilient in the face of invalid records (e.g., invalid formatting,
579 * length, MAC, etc.). In general, invalid records SHOULD be silently
580 * discarded, thus preserving the association; however, an error MAY be
581 * logged for diagnostic purposes."
584 /* this packet contained a partial record, dump it */
585 if (n < DTLS1_RT_HEADER_LENGTH) {
586 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_RECORD_TOO_SMALL);
591 s->msg_callback(0, 0, SSL3_RT_HEADER, buf,
592 DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
594 /* Get the record header */
595 if (!PACKET_get_1(&pkt, &rectype)
596 || !PACKET_get_1(&pkt, &versmajor)) {
597 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
601 if (rectype != SSL3_RT_HANDSHAKE) {
602 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
607 * Check record version number. We only check that the major version is
610 if (versmajor != DTLS1_VERSION_MAJOR) {
611 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_BAD_PROTOCOL_VERSION_NUMBER);
615 if (!PACKET_forward(&pkt, 1)
616 /* Save the sequence number: 64 bits, with top 2 bytes = epoch */
617 || !PACKET_copy_bytes(&pkt, seq, SEQ_NUM_SIZE)
618 || !PACKET_get_length_prefixed_2(&pkt, &msgpkt)) {
619 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
623 * We allow data remaining at the end of the packet because there could
624 * be a second record (but we ignore it)
627 /* This is an initial ClientHello so the epoch has to be 0 */
628 if (seq[0] != 0 || seq[1] != 0) {
629 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
633 /* Get a pointer to the raw message for the later callback */
634 data = PACKET_data(&msgpkt);
636 /* Finished processing the record header, now process the message */
637 if (!PACKET_get_1(&msgpkt, &msgtype)
638 || !PACKET_get_net_3(&msgpkt, &msglen)
639 || !PACKET_get_net_2(&msgpkt, &msgseq)
640 || !PACKET_get_net_3(&msgpkt, &fragoff)
641 || !PACKET_get_net_3(&msgpkt, &fraglen)
642 || !PACKET_get_sub_packet(&msgpkt, &msgpayload, fraglen)
643 || PACKET_remaining(&msgpkt) != 0) {
644 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
648 if (msgtype != SSL3_MT_CLIENT_HELLO) {
649 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
653 /* Message sequence number can only be 0 or 1 */
655 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_INVALID_SEQUENCE_NUMBER);
660 * We don't support fragment reassembly for ClientHellos whilst
661 * listening because that would require server side state (which is
662 * against the whole point of the ClientHello/HelloVerifyRequest
663 * mechanism). Instead we only look at the first ClientHello fragment
664 * and require that the cookie must be contained within it.
666 if (fragoff != 0 || fraglen > msglen) {
667 /* Non initial ClientHello fragment (or bad fragment) */
668 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_FRAGMENTED_CLIENT_HELLO);
673 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, data,
674 fraglen + DTLS1_HM_HEADER_LENGTH, s,
675 s->msg_callback_arg);
677 if (!PACKET_get_net_2(&msgpayload, &clientvers)) {
678 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
683 * Verify client version is supported
685 if (DTLS_VERSION_LT(clientvers, (unsigned int)s->method->version) &&
686 s->method->version != DTLS_ANY_VERSION) {
687 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_WRONG_VERSION_NUMBER);
691 if (!PACKET_forward(&msgpayload, SSL3_RANDOM_SIZE)
692 || !PACKET_get_length_prefixed_1(&msgpayload, &session)
693 || !PACKET_get_length_prefixed_1(&msgpayload, &cookiepkt)) {
695 * Could be malformed or the cookie does not fit within the initial
696 * ClientHello fragment. Either way we can't handle it.
698 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
703 * Check if we have a cookie or not. If not we need to send a
704 * HelloVerifyRequest.
706 if (PACKET_remaining(&cookiepkt) == 0) {
707 next = LISTEN_SEND_VERIFY_REQUEST;
710 * We have a cookie, so lets check it.
712 if (s->ctx->app_verify_cookie_cb == NULL) {
713 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_NO_VERIFY_COOKIE_CALLBACK);
717 if (s->ctx->app_verify_cookie_cb(s, PACKET_data(&cookiepkt),
718 PACKET_remaining(&cookiepkt)) ==
721 * We treat invalid cookies in the same was as no cookie as
724 next = LISTEN_SEND_VERIFY_REQUEST;
726 /* Cookie verification succeeded */
727 next = LISTEN_SUCCESS;
731 if (next == LISTEN_SEND_VERIFY_REQUEST) {
733 * There was no cookie in the ClientHello so we need to send a
734 * HelloVerifyRequest. If this fails we do not worry about trying
735 * to resend, we just drop it.
739 * Dump the read packet, we don't need it any more. Ignore return
742 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 0, NULL);
743 BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
744 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL);
746 /* Generate the cookie */
747 if (s->ctx->app_gen_cookie_cb == NULL ||
748 s->ctx->app_gen_cookie_cb(s, cookie, &cookielen) == 0 ||
750 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_COOKIE_GEN_CALLBACK_FAILURE);
755 p = &buf[DTLS1_RT_HEADER_LENGTH];
756 msglen = dtls_raw_hello_verify_request(p + DTLS1_HM_HEADER_LENGTH,
759 *p++ = DTLS1_MT_HELLO_VERIFY_REQUEST;
764 /* Message sequence number is always 0 for a HelloVerifyRequest */
768 * We never fragment a HelloVerifyRequest, so fragment offset is 0
769 * and fragment length is message length
774 /* Set reclen equal to length of whole handshake message */
775 reclen = msglen + DTLS1_HM_HEADER_LENGTH;
777 /* Add the record header */
780 *(p++) = SSL3_RT_HANDSHAKE;
782 * Special case: for hello verify request, client version 1.0 and we
783 * haven't decided which version to use yet send back using version
784 * 1.0 header: otherwise some clients will ignore it.
786 if (s->method->version == DTLS_ANY_VERSION) {
787 *(p++) = DTLS1_VERSION >> 8;
788 *(p++) = DTLS1_VERSION & 0xff;
790 *(p++) = s->version >> 8;
791 *(p++) = s->version & 0xff;
795 * Record sequence number is always the same as in the received
798 memcpy(p, seq, SEQ_NUM_SIZE);
805 * Set reclen equal to length of whole record including record
808 reclen += DTLS1_RT_HEADER_LENGTH;
811 s->msg_callback(1, 0, SSL3_RT_HEADER, buf,
812 DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
815 if ((tmpclient = BIO_ADDR_new()) == NULL) {
816 SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE);
821 * This is unneccessary if rbio and wbio are one and the same - but
822 * maybe they're not. We ignore errors here - some BIOs do not
825 if(BIO_dgram_get_peer(rbio, tmpclient) > 0) {
826 (void)BIO_dgram_set_peer(wbio, tmpclient);
828 BIO_ADDR_free(tmpclient);
831 if (BIO_write(wbio, buf, reclen) < (int)reclen) {
832 if(BIO_should_retry(wbio)) {
834 * Non-blocking IO...but we're stateless, so we're just
835 * going to drop this packet.
842 if (BIO_flush(wbio) <= 0) {
843 if(BIO_should_retry(wbio)) {
845 * Non-blocking IO...but we're stateless, so we're just
846 * going to drop this packet.
853 } while (next != LISTEN_SUCCESS);
856 * Set expected sequence numbers to continue the handshake.
858 s->d1->handshake_read_seq = 1;
859 s->d1->handshake_write_seq = 1;
860 s->d1->next_handshake_write_seq = 1;
861 DTLS_RECORD_LAYER_set_write_sequence(&s->rlayer, seq);
864 * We are doing cookie exchange, so make sure we set that option in the
867 SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
870 * Tell the state machine that we've done the initial hello verify
873 ossl_statem_set_hello_verify_done(s);
875 /* Some BIOs may not support this. If we fail we clear the client address */
876 if (BIO_dgram_get_peer(rbio, client) <= 0)
877 BIO_ADDR_clear(client);
882 BIO_ADDR_free(tmpclient);
883 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 0, NULL);
885 /* Dump this packet. Ignore return value */
886 BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
891 static int dtls1_set_handshake_header(SSL *s, int htype, unsigned long len)
893 unsigned char *p = (unsigned char *)s->init_buf->data;
894 dtls1_set_message_header(s, p, htype, len, 0, len);
895 s->init_num = (int)len + DTLS1_HM_HEADER_LENGTH;
897 /* Buffer the message to handle re-xmits */
899 if (!dtls1_buffer_message(s, 0))
905 static int dtls1_handshake_write(SSL *s)
907 return dtls1_do_write(s, SSL3_RT_HANDSHAKE);
910 #ifndef OPENSSL_NO_HEARTBEATS
911 int dtls1_process_heartbeat(SSL *s, unsigned char *p, unsigned int length)
914 unsigned short hbtype;
915 unsigned int payload;
916 unsigned int padding = 16; /* Use minimum padding */
919 s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
920 p, length, s, s->msg_callback_arg);
922 /* Read type and payload length first */
923 if (1 + 2 + 16 > length)
924 return 0; /* silently discard */
925 if (length > SSL3_RT_MAX_PLAIN_LENGTH)
926 return 0; /* silently discard per RFC 6520 sec. 4 */
930 if (1 + 2 + payload + 16 > length)
931 return 0; /* silently discard per RFC 6520 sec. 4 */
934 if (hbtype == TLS1_HB_REQUEST) {
935 unsigned char *buffer, *bp;
936 unsigned int write_length = 1 /* heartbeat type */ +
937 2 /* heartbeat length */ +
941 if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
945 * Allocate memory for the response, size is 1 byte message type,
946 * plus 2 bytes payload length, plus payload, plus padding
948 buffer = OPENSSL_malloc(write_length);
953 /* Enter response type, length and copy payload */
954 *bp++ = TLS1_HB_RESPONSE;
956 memcpy(bp, pl, payload);
959 if (RAND_bytes(bp, padding) <= 0) {
960 OPENSSL_free(buffer);
964 r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, write_length);
966 if (r >= 0 && s->msg_callback)
967 s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
968 buffer, write_length, s, s->msg_callback_arg);
970 OPENSSL_free(buffer);
974 } else if (hbtype == TLS1_HB_RESPONSE) {
978 * We only send sequence numbers (2 bytes unsigned int), and 16
979 * random bytes, so we just try to read the sequence number
983 if (payload == 18 && seq == s->tlsext_hb_seq) {
986 s->tlsext_hb_pending = 0;
993 int dtls1_heartbeat(SSL *s)
995 unsigned char *buf, *p;
997 unsigned int payload = 18; /* Sequence number + random bytes */
998 unsigned int padding = 16; /* Use minimum padding */
1000 /* Only send if peer supports and accepts HB requests... */
1001 if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
1002 s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS) {
1003 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
1007 /* ...and there is none in flight yet... */
1008 if (s->tlsext_hb_pending) {
1009 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PENDING);
1013 /* ...and no handshake in progress. */
1014 if (SSL_in_init(s) || ossl_statem_get_in_handshake(s)) {
1015 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_UNEXPECTED_MESSAGE);
1020 * Create HeartBeat message, we just use a sequence number
1021 * as payload to distuingish different messages and add
1022 * some random stuff.
1023 * - Message Type, 1 byte
1024 * - Payload Length, 2 bytes (unsigned int)
1025 * - Payload, the sequence number (2 bytes uint)
1026 * - Payload, random bytes (16 bytes uint)
1029 buf = OPENSSL_malloc(1 + 2 + payload + padding);
1031 SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_MALLOC_FAILURE);
1036 *p++ = TLS1_HB_REQUEST;
1037 /* Payload length (18 bytes here) */
1039 /* Sequence number */
1040 s2n(s->tlsext_hb_seq, p);
1041 /* 16 random bytes */
1042 if (RAND_bytes(p, 16) <= 0) {
1043 SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_INTERNAL_ERROR);
1047 /* Random padding */
1048 if (RAND_bytes(p, padding) <= 0) {
1049 SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_INTERNAL_ERROR);
1053 ret = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buf, 3 + payload + padding);
1055 if (s->msg_callback)
1056 s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1057 buf, 3 + payload + padding,
1058 s, s->msg_callback_arg);
1060 dtls1_start_timer(s);
1061 s->tlsext_hb_pending = 1;
1071 int dtls1_shutdown(SSL *s)
1074 #ifndef OPENSSL_NO_SCTP
1077 wbio = SSL_get_wbio(s);
1078 if (wbio != NULL && BIO_dgram_is_sctp(wbio) &&
1079 !(s->shutdown & SSL_SENT_SHUTDOWN)) {
1080 ret = BIO_dgram_sctp_wait_for_dry(wbio);
1085 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1,
1089 ret = ssl3_shutdown(s);
1090 #ifndef OPENSSL_NO_SCTP
1091 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
1096 int dtls1_query_mtu(SSL *s)
1098 if (s->d1->link_mtu) {
1100 s->d1->link_mtu - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
1101 s->d1->link_mtu = 0;
1104 /* AHA! Figure out the MTU, and stick to the right size */
1105 if (s->d1->mtu < dtls1_min_mtu(s)) {
1106 if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
1108 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
1111 * I've seen the kernel return bogus numbers when it doesn't know
1112 * (initial write), so just make sure we have a reasonable number
1114 if (s->d1->mtu < dtls1_min_mtu(s)) {
1115 /* Set to min mtu */
1116 s->d1->mtu = dtls1_min_mtu(s);
1117 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
1126 static unsigned int dtls1_link_min_mtu(void)
1128 return (g_probable_mtu[(sizeof(g_probable_mtu) /
1129 sizeof(g_probable_mtu[0])) - 1]);
1132 unsigned int dtls1_min_mtu(SSL *s)
1134 return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));