3 * DTLS implementation written by Nagendra Modadugu
4 * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
6 /* ====================================================================
7 * Copyright (c) 1998-2005 The OpenSSL Project. All rights reserved.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in
18 * the documentation and/or other materials provided with the
21 * 3. All advertising materials mentioning features or use of this
22 * software must display the following acknowledgment:
23 * "This product includes software developed by the OpenSSL Project
24 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
26 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
27 * endorse or promote products derived from this software without
28 * prior written permission. For written permission, please contact
29 * openssl-core@openssl.org.
31 * 5. Products derived from this software may not be called "OpenSSL"
32 * nor may "OpenSSL" appear in their names without prior written
33 * permission of the OpenSSL Project.
35 * 6. Redistributions of any form whatsoever must retain the following
37 * "This product includes software developed by the OpenSSL Project
38 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
40 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
41 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
43 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
44 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
45 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
46 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
47 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
49 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
50 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
51 * OF THE POSSIBILITY OF SUCH DAMAGE.
52 * ====================================================================
54 * This product includes cryptographic software written by Eric Young
55 * (eay@cryptsoft.com). This product includes software written by Tim
56 * Hudson (tjh@cryptsoft.com).
59 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
60 * All rights reserved.
62 * This package is an SSL implementation written
63 * by Eric Young (eay@cryptsoft.com).
64 * The implementation was written so as to conform with Netscapes SSL.
66 * This library is free for commercial and non-commercial use as long as
67 * the following conditions are aheared to. The following conditions
68 * apply to all code found in this distribution, be it the RC4, RSA,
69 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
70 * included with this distribution is covered by the same copyright terms
71 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
73 * Copyright remains Eric Young's, and as such any Copyright notices in
74 * the code are not to be removed.
75 * If this package is used in a product, Eric Young should be given attribution
76 * as the author of the parts of the library used.
77 * This can be in the form of a textual message at program startup or
78 * in documentation (online or textual) provided with the package.
80 * Redistribution and use in source and binary forms, with or without
81 * modification, are permitted provided that the following conditions
83 * 1. Redistributions of source code must retain the copyright
84 * notice, this list of conditions and the following disclaimer.
85 * 2. Redistributions in binary form must reproduce the above copyright
86 * notice, this list of conditions and the following disclaimer in the
87 * documentation and/or other materials provided with the distribution.
88 * 3. All advertising materials mentioning features or use of this software
89 * must display the following acknowledgement:
90 * "This product includes cryptographic software written by
91 * Eric Young (eay@cryptsoft.com)"
92 * The word 'cryptographic' can be left out if the rouines from the library
93 * being used are not cryptographic related :-).
94 * 4. If you include any Windows specific code (or a derivative thereof) from
95 * the apps directory (application code) you must include an acknowledgement:
96 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
98 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
99 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
100 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
101 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
102 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
103 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
104 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
105 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
106 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
107 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
110 * The licence and distribution terms for any publically available version or
111 * derivative of this code cannot be changed. i.e. this code cannot simply be
112 * copied and put under another distribution licence
113 * [including the GNU Public Licence.]
119 #include "ssl_locl.h"
120 #include <openssl/buffer.h>
121 #include <openssl/rand.h>
122 #include <openssl/objects.h>
123 #include <openssl/evp.h>
124 #include <openssl/x509.h>
126 #define RSMBLY_BITMASK_SIZE(msg_len) (((msg_len) + 7) / 8)
128 #define RSMBLY_BITMASK_MARK(bitmask, start, end) { \
129 if ((end) - (start) <= 8) { \
131 for (ii = (start); ii < (end); ii++) bitmask[((ii) >> 3)] |= (1 << ((ii) & 7)); \
134 bitmask[((start) >> 3)] |= bitmask_start_values[((start) & 7)]; \
135 for (ii = (((start) >> 3) + 1); ii < ((((end) - 1)) >> 3); ii++) bitmask[ii] = 0xff; \
136 bitmask[(((end) - 1) >> 3)] |= bitmask_end_values[((end) & 7)]; \
139 #define RSMBLY_BITMASK_IS_COMPLETE(bitmask, msg_len, is_complete) { \
141 OPENSSL_assert((msg_len) > 0); \
143 if (bitmask[(((msg_len) - 1) >> 3)] != bitmask_end_values[((msg_len) & 7)]) is_complete = 0; \
144 if (is_complete) for (ii = (((msg_len) - 1) >> 3) - 1; ii >= 0 ; ii--) \
145 if (bitmask[ii] != 0xff) { is_complete = 0; break; } }
148 # define RSMBLY_BITMASK_PRINT(bitmask, msg_len) { \
150 printf("bitmask: "); for (ii = 0; ii < (msg_len); ii++) \
151 printf("%d ", (bitmask[ii >> 3] & (1 << (ii & 7))) >> (ii & 7)); \
155 static unsigned char bitmask_start_values[] =
156 { 0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80 };
157 static unsigned char bitmask_end_values[] =
158 { 0xff, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f };
160 /* XDTLS: figure out the right values */
161 static const unsigned int g_probable_mtu[] = { 1500, 512, 256 };
163 static void dtls1_fix_message_header(SSL *s, unsigned long frag_off,
164 unsigned long frag_len);
165 static unsigned char *dtls1_write_message_header(SSL *s, unsigned char *p);
166 static void dtls1_set_message_header_int(SSL *s, unsigned char mt,
168 unsigned short seq_num,
169 unsigned long frag_off,
170 unsigned long frag_len);
171 static long dtls1_get_message_fragment(SSL *s, int st1, int stn, long max,
174 static hm_fragment *dtls1_hm_fragment_new(unsigned long frag_len,
177 hm_fragment *frag = NULL;
178 unsigned char *buf = NULL;
179 unsigned char *bitmask = NULL;
181 frag = (hm_fragment *)OPENSSL_malloc(sizeof(hm_fragment));
186 buf = (unsigned char *)OPENSSL_malloc(frag_len);
193 /* zero length fragment gets zero frag->fragment */
194 frag->fragment = buf;
196 /* Initialize reassembly bitmask if necessary */
199 (unsigned char *)OPENSSL_malloc(RSMBLY_BITMASK_SIZE(frag_len));
200 if (bitmask == NULL) {
206 memset(bitmask, 0, RSMBLY_BITMASK_SIZE(frag_len));
209 frag->reassembly = bitmask;
214 void dtls1_hm_fragment_free(hm_fragment *frag)
217 if (frag->msg_header.is_ccs) {
218 EVP_CIPHER_CTX_free(frag->msg_header.
219 saved_retransmit_state.enc_write_ctx);
220 EVP_MD_CTX_destroy(frag->msg_header.
221 saved_retransmit_state.write_hash);
224 OPENSSL_free(frag->fragment);
225 if (frag->reassembly)
226 OPENSSL_free(frag->reassembly);
230 static int dtls1_query_mtu(SSL *s)
232 if (s->d1->link_mtu) {
234 s->d1->link_mtu - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
238 /* AHA! Figure out the MTU, and stick to the right size */
239 if (s->d1->mtu < dtls1_min_mtu(s)) {
240 if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
242 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
245 * I've seen the kernel return bogus numbers when it doesn't know
246 * (initial write), so just make sure we have a reasonable number
248 if (s->d1->mtu < dtls1_min_mtu(s)) {
250 s->d1->mtu = dtls1_min_mtu(s);
251 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
261 * send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or
262 * SSL3_RT_CHANGE_CIPHER_SPEC)
264 int dtls1_do_write(SSL *s, int type)
267 unsigned int curr_mtu;
269 unsigned int len, frag_off, mac_size, blocksize, used_len;
271 if (!dtls1_query_mtu(s))
274 OPENSSL_assert(s->d1->mtu >= dtls1_min_mtu(s)); /* should have something
277 if (s->init_off == 0 && type == SSL3_RT_HANDSHAKE)
278 OPENSSL_assert(s->init_num ==
279 (int)s->d1->w_msg_hdr.msg_len +
280 DTLS1_HM_HEADER_LENGTH);
283 mac_size = EVP_MD_CTX_size(s->write_hash);
287 if (s->enc_write_ctx &&
288 (EVP_CIPHER_mode(s->enc_write_ctx->cipher) & EVP_CIPH_CBC_MODE))
289 blocksize = 2 * EVP_CIPHER_block_size(s->enc_write_ctx->cipher);
294 /* s->init_num shouldn't ever be < 0...but just in case */
295 while (s->init_num > 0) {
296 used_len = BIO_wpending(SSL_get_wbio(s)) + DTLS1_RT_HEADER_LENGTH
297 + mac_size + blocksize;
298 if (s->d1->mtu > used_len)
299 curr_mtu = s->d1->mtu - used_len;
303 if (curr_mtu <= DTLS1_HM_HEADER_LENGTH) {
305 * grr.. we could get an error if MTU picked was wrong
307 ret = BIO_flush(SSL_get_wbio(s));
310 used_len = DTLS1_RT_HEADER_LENGTH + mac_size + blocksize;
311 if (s->d1->mtu > used_len + DTLS1_HM_HEADER_LENGTH) {
312 curr_mtu = s->d1->mtu - used_len;
314 /* Shouldn't happen */
320 * We just checked that s->init_num > 0 so this cast should be safe
322 if (((unsigned int)s->init_num) > curr_mtu)
327 /* Shouldn't ever happen */
332 * XDTLS: this function is too long. split out the CCS part
334 if (type == SSL3_RT_HANDSHAKE) {
335 if (s->init_off != 0) {
336 OPENSSL_assert(s->init_off > DTLS1_HM_HEADER_LENGTH);
337 s->init_off -= DTLS1_HM_HEADER_LENGTH;
338 s->init_num += DTLS1_HM_HEADER_LENGTH;
341 * We just checked that s->init_num > 0 so this cast should
344 if (((unsigned int)s->init_num) > curr_mtu)
350 /* Shouldn't ever happen */
354 if (len < DTLS1_HM_HEADER_LENGTH) {
356 * len is so small that we really can't do anything sensible
361 dtls1_fix_message_header(s, frag_off,
362 len - DTLS1_HM_HEADER_LENGTH);
364 dtls1_write_message_header(s,
365 (unsigned char *)&s->init_buf->
369 ret = dtls1_write_bytes(s, type, &s->init_buf->data[s->init_off],
373 * might need to update MTU here, but we don't know which
374 * previous packet caused the failure -- so can't really
375 * retransmit anything. continue as if everything is fine and
376 * wait for an alert to handle the retransmit
378 if (retry && BIO_ctrl(SSL_get_wbio(s),
379 BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0) {
380 if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
381 if (!dtls1_query_mtu(s))
383 /* Have one more go */
393 * bad if this assert fails, only part of the handshake message
394 * got sent. but why would this happen?
396 OPENSSL_assert(len == (unsigned int)ret);
398 if (type == SSL3_RT_HANDSHAKE && !s->d1->retransmitting) {
400 * should not be done for 'Hello Request's, but in that case
401 * we'll ignore the result anyway
404 (unsigned char *)&s->init_buf->data[s->init_off];
405 const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
408 if (frag_off == 0 && s->version != DTLS1_BAD_VER) {
410 * reconstruct message header is if it is being sent in
413 *p++ = msg_hdr->type;
414 l2n3(msg_hdr->msg_len, p);
415 s2n(msg_hdr->seq, p);
417 l2n3(msg_hdr->msg_len, p);
418 p -= DTLS1_HM_HEADER_LENGTH;
421 p += DTLS1_HM_HEADER_LENGTH;
422 xlen = ret - DTLS1_HM_HEADER_LENGTH;
425 ssl3_finish_mac(s, p, xlen);
428 if (ret == s->init_num) {
430 s->msg_callback(1, s->version, type, s->init_buf->data,
431 (size_t)(s->init_off + s->init_num), s,
432 s->msg_callback_arg);
434 s->init_off = 0; /* done writing this message */
441 frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
448 * Obtain handshake message of message type 'mt' (any if mt == -1), maximum
449 * acceptable body length 'max'. Read an entire handshake message. Handshake
450 * messages arrive in fragments.
452 long dtls1_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
455 struct hm_header_st *msg_hdr;
457 unsigned long msg_len;
460 * s3->tmp is used to store messages that are unexpected, caused by the
461 * absence of an optional handshake message
463 if (s->s3->tmp.reuse_message) {
464 s->s3->tmp.reuse_message = 0;
465 if ((mt >= 0) && (s->s3->tmp.message_type != mt)) {
466 al = SSL_AD_UNEXPECTED_MESSAGE;
467 SSLerr(SSL_F_DTLS1_GET_MESSAGE, SSL_R_UNEXPECTED_MESSAGE);
471 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
472 s->init_num = (int)s->s3->tmp.message_size;
476 msg_hdr = &s->d1->r_msg_hdr;
477 memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
480 i = dtls1_get_message_fragment(s, st1, stn, max, ok);
481 if (i == DTLS1_HM_BAD_FRAGMENT || i == DTLS1_HM_FRAGMENT_RETRY) {
482 /* bad fragment received */
484 } else if (i <= 0 && !*ok) {
488 if (mt >= 0 && s->s3->tmp.message_type != mt) {
489 al = SSL_AD_UNEXPECTED_MESSAGE;
490 SSLerr(SSL_F_DTLS1_GET_MESSAGE, SSL_R_UNEXPECTED_MESSAGE);
494 p = (unsigned char *)s->init_buf->data;
495 msg_len = msg_hdr->msg_len;
497 /* reconstruct message header */
498 *(p++) = msg_hdr->type;
500 s2n(msg_hdr->seq, p);
503 if (s->version != DTLS1_BAD_VER) {
504 p -= DTLS1_HM_HEADER_LENGTH;
505 msg_len += DTLS1_HM_HEADER_LENGTH;
508 ssl3_finish_mac(s, p, msg_len);
510 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
511 p, msg_len, s, s->msg_callback_arg);
513 memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
515 /* Don't change sequence numbers while listening */
517 s->d1->handshake_read_seq++;
519 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
523 ssl3_send_alert(s, SSL3_AL_FATAL, al);
528 static int dtls1_preprocess_fragment(SSL *s, struct hm_header_st *msg_hdr,
531 size_t frag_off, frag_len, msg_len;
533 msg_len = msg_hdr->msg_len;
534 frag_off = msg_hdr->frag_off;
535 frag_len = msg_hdr->frag_len;
537 /* sanity checking */
538 if ((frag_off + frag_len) > msg_len) {
539 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT, SSL_R_EXCESSIVE_MESSAGE_SIZE);
540 return SSL_AD_ILLEGAL_PARAMETER;
543 if ((frag_off + frag_len) > (unsigned long)max) {
544 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT, SSL_R_EXCESSIVE_MESSAGE_SIZE);
545 return SSL_AD_ILLEGAL_PARAMETER;
548 if (s->d1->r_msg_hdr.frag_off == 0) { /* first fragment */
550 * msg_len is limited to 2^24, but is effectively checked against max
553 if (!BUF_MEM_grow_clean
554 (s->init_buf, msg_len + DTLS1_HM_HEADER_LENGTH)) {
555 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT, ERR_R_BUF_LIB);
556 return SSL_AD_INTERNAL_ERROR;
559 s->s3->tmp.message_size = msg_len;
560 s->d1->r_msg_hdr.msg_len = msg_len;
561 s->s3->tmp.message_type = msg_hdr->type;
562 s->d1->r_msg_hdr.type = msg_hdr->type;
563 s->d1->r_msg_hdr.seq = msg_hdr->seq;
564 } else if (msg_len != s->d1->r_msg_hdr.msg_len) {
566 * They must be playing with us! BTW, failure to enforce upper limit
567 * would open possibility for buffer overrun.
569 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT, SSL_R_EXCESSIVE_MESSAGE_SIZE);
570 return SSL_AD_ILLEGAL_PARAMETER;
573 return 0; /* no error */
576 static int dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok)
579 * (0) check whether the desired fragment is available
581 * (1) copy over the fragment to s->init_buf->data[]
582 * (2) update s->init_num
590 item = pqueue_peek(s->d1->buffered_messages);
594 frag = (hm_fragment *)item->data;
596 if (frag->msg_header.seq < s->d1->handshake_read_seq) {
597 /* This is a stale message that has been buffered so clear it */
598 pqueue_pop(s->d1->buffered_messages);
599 dtls1_hm_fragment_free(frag);
604 } while (item == NULL);
607 /* Don't return if reassembly still in progress */
608 if (frag->reassembly != NULL)
611 if (s->d1->handshake_read_seq == frag->msg_header.seq) {
612 unsigned long frag_len = frag->msg_header.frag_len;
613 pqueue_pop(s->d1->buffered_messages);
615 al = dtls1_preprocess_fragment(s, &frag->msg_header, max);
617 if (al == 0) { /* no alert */
619 (unsigned char *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
620 memcpy(&p[frag->msg_header.frag_off], frag->fragment,
621 frag->msg_header.frag_len);
624 dtls1_hm_fragment_free(frag);
632 ssl3_send_alert(s, SSL3_AL_FATAL, al);
641 * dtls1_max_handshake_message_len returns the maximum number of bytes
642 * permitted in a DTLS handshake message for |s|. The minimum is 16KB, but
643 * may be greater if the maximum certificate list size requires it.
645 static unsigned long dtls1_max_handshake_message_len(const SSL *s)
647 unsigned long max_len =
648 DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
649 if (max_len < (unsigned long)s->max_cert_list)
650 return s->max_cert_list;
655 dtls1_reassemble_fragment(SSL *s, const struct hm_header_st *msg_hdr, int *ok)
657 hm_fragment *frag = NULL;
659 int i = -1, is_complete;
660 unsigned char seq64be[8];
661 unsigned long frag_len = msg_hdr->frag_len;
663 if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len ||
664 msg_hdr->msg_len > dtls1_max_handshake_message_len(s))
668 return DTLS1_HM_FRAGMENT_RETRY;
670 /* Try to find item in queue */
671 memset(seq64be, 0, sizeof(seq64be));
672 seq64be[6] = (unsigned char)(msg_hdr->seq >> 8);
673 seq64be[7] = (unsigned char)msg_hdr->seq;
674 item = pqueue_find(s->d1->buffered_messages, seq64be);
677 frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1);
680 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
681 frag->msg_header.frag_len = frag->msg_header.msg_len;
682 frag->msg_header.frag_off = 0;
684 frag = (hm_fragment *)item->data;
685 if (frag->msg_header.msg_len != msg_hdr->msg_len) {
693 * If message is already reassembled, this must be a retransmit and can
694 * be dropped. In this case item != NULL and so frag does not need to be
697 if (frag->reassembly == NULL) {
698 unsigned char devnull[256];
701 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
704 sizeof(devnull) ? sizeof(devnull) :
710 return DTLS1_HM_FRAGMENT_RETRY;
713 /* read the body of the fragment (header has already been read */
714 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
715 frag->fragment + msg_hdr->frag_off,
717 if ((unsigned long)i != frag_len)
722 RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off,
723 (long)(msg_hdr->frag_off + frag_len));
725 RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len,
729 OPENSSL_free(frag->reassembly);
730 frag->reassembly = NULL;
734 item = pitem_new(seq64be, frag);
740 item = pqueue_insert(s->d1->buffered_messages, item);
742 * pqueue_insert fails iff a duplicate item is inserted. However,
743 * |item| cannot be a duplicate. If it were, |pqueue_find|, above,
744 * would have returned it and control would never have reached this
747 OPENSSL_assert(item != NULL);
750 return DTLS1_HM_FRAGMENT_RETRY;
753 if (frag != NULL && item == NULL)
754 dtls1_hm_fragment_free(frag);
760 dtls1_process_out_of_seq_message(SSL *s, const struct hm_header_st *msg_hdr,
764 hm_fragment *frag = NULL;
766 unsigned char seq64be[8];
767 unsigned long frag_len = msg_hdr->frag_len;
769 if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len)
772 /* Try to find item in queue, to prevent duplicate entries */
773 memset(seq64be, 0, sizeof(seq64be));
774 seq64be[6] = (unsigned char)(msg_hdr->seq >> 8);
775 seq64be[7] = (unsigned char)msg_hdr->seq;
776 item = pqueue_find(s->d1->buffered_messages, seq64be);
779 * If we already have an entry and this one is a fragment, don't discard
780 * it and rather try to reassemble it.
782 if (item != NULL && frag_len != msg_hdr->msg_len)
786 * Discard the message if sequence number was already there, is too far
787 * in the future, already in the queue or if we received a FINISHED
788 * before the SERVER_HELLO, which then must be a stale retransmit.
790 if (msg_hdr->seq <= s->d1->handshake_read_seq ||
791 msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL ||
792 (s->d1->handshake_read_seq == 0 && msg_hdr->type == SSL3_MT_FINISHED))
794 unsigned char devnull[256];
797 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
800 sizeof(devnull) ? sizeof(devnull) :
807 if (frag_len != msg_hdr->msg_len)
808 return dtls1_reassemble_fragment(s, msg_hdr, ok);
810 if (frag_len > dtls1_max_handshake_message_len(s))
813 frag = dtls1_hm_fragment_new(frag_len, 0);
817 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
821 * read the body of the fragment (header has already been read
823 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
824 frag->fragment, frag_len, 0);
825 if ((unsigned long)i != frag_len)
831 item = pitem_new(seq64be, frag);
835 item = pqueue_insert(s->d1->buffered_messages, item);
837 * pqueue_insert fails iff a duplicate item is inserted. However,
838 * |item| cannot be a duplicate. If it were, |pqueue_find|, above,
839 * would have returned it. Then, either |frag_len| !=
840 * |msg_hdr->msg_len| in which case |item| is set to NULL and it will
841 * have been processed with |dtls1_reassemble_fragment|, above, or
842 * the record will have been discarded.
844 OPENSSL_assert(item != NULL);
847 return DTLS1_HM_FRAGMENT_RETRY;
850 if (frag != NULL && item == NULL)
851 dtls1_hm_fragment_free(frag);
857 dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
859 unsigned char wire[DTLS1_HM_HEADER_LENGTH];
860 unsigned long len, frag_off, frag_len;
862 struct hm_header_st msg_hdr;
865 /* see if we have the required fragment already */
866 if ((frag_len = dtls1_retrieve_buffered_fragment(s, max, ok)) || *ok) {
868 s->init_num = frag_len;
872 /* read handshake message header */
873 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, wire,
874 DTLS1_HM_HEADER_LENGTH, 0);
875 if (i <= 0) { /* nbio, or an error */
876 s->rwstate = SSL_READING;
880 /* Handshake fails if message header is incomplete */
881 if (i != DTLS1_HM_HEADER_LENGTH) {
882 al = SSL_AD_UNEXPECTED_MESSAGE;
883 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT, SSL_R_UNEXPECTED_MESSAGE);
887 /* parse the message fragment header */
888 dtls1_get_message_header(wire, &msg_hdr);
890 len = msg_hdr.msg_len;
891 frag_off = msg_hdr.frag_off;
892 frag_len = msg_hdr.frag_len;
895 * We must have at least frag_len bytes left in the record to be read.
896 * Fragments must not span records.
898 if (frag_len > s->s3->rrec.length) {
899 al = SSL3_AD_ILLEGAL_PARAMETER;
900 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT, SSL_R_BAD_LENGTH);
905 * if this is a future (or stale) message it gets buffered
906 * (or dropped)--no further processing at this time
907 * While listening, we accept seq 1 (ClientHello with cookie)
908 * although we're still expecting seq 0 (ClientHello)
910 if (msg_hdr.seq != s->d1->handshake_read_seq
911 && !(s->d1->listen && msg_hdr.seq == 1))
912 return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
914 if (frag_len && frag_len < len)
915 return dtls1_reassemble_fragment(s, &msg_hdr, ok);
917 if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
918 wire[0] == SSL3_MT_HELLO_REQUEST) {
920 * The server may always send 'Hello Request' messages -- we are
921 * doing a handshake anyway now, so ignore them if their format is
922 * correct. Does not count for 'Finished' MAC.
924 if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0) {
926 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
927 wire, DTLS1_HM_HEADER_LENGTH, s,
928 s->msg_callback_arg);
932 } else { /* Incorrectly formated Hello request */
934 al = SSL_AD_UNEXPECTED_MESSAGE;
935 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,
936 SSL_R_UNEXPECTED_MESSAGE);
941 if ((al = dtls1_preprocess_fragment(s, &msg_hdr, max)))
946 (unsigned char *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
948 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
949 &p[frag_off], frag_len, 0);
952 * This shouldn't ever fail due to NBIO because we already checked
953 * that we have enough data in the record
956 s->rwstate = SSL_READING;
964 * XDTLS: an incorrectly formatted fragment should cause the handshake
967 if (i != (int)frag_len) {
968 al = SSL3_AD_ILLEGAL_PARAMETER;
969 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT, SSL3_AD_ILLEGAL_PARAMETER);
977 * Note that s->init_num is *not* used as current offset in
978 * s->init_buf->data, but as a counter summing up fragments' lengths: as
979 * soon as they sum up to handshake packet length, we assume we have got
982 s->init_num = frag_len;
986 ssl3_send_alert(s, SSL3_AL_FATAL, al);
993 int dtls1_send_finished(SSL *s, int a, int b, const char *sender, int slen)
995 unsigned char *p, *d;
1000 d = (unsigned char *)s->init_buf->data;
1001 p = &(d[DTLS1_HM_HEADER_LENGTH]);
1003 i = s->method->ssl3_enc->final_finish_mac(s,
1005 s->s3->tmp.finish_md);
1006 s->s3->tmp.finish_md_len = i;
1007 memcpy(p, s->s3->tmp.finish_md, i);
1012 * Copy the finished so we can use it for renegotiation checks
1014 if (s->type == SSL_ST_CONNECT) {
1015 OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
1016 memcpy(s->s3->previous_client_finished, s->s3->tmp.finish_md, i);
1017 s->s3->previous_client_finished_len = i;
1019 OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
1020 memcpy(s->s3->previous_server_finished, s->s3->tmp.finish_md, i);
1021 s->s3->previous_server_finished_len = i;
1024 #ifdef OPENSSL_SYS_WIN16
1026 * MSVC 1.5 does not clear the top bytes of the word unless I do
1032 d = dtls1_set_message_header(s, d, SSL3_MT_FINISHED, l, 0, l);
1033 s->init_num = (int)l + DTLS1_HM_HEADER_LENGTH;
1036 /* buffer the message to handle re-xmits */
1037 dtls1_buffer_message(s, 0);
1042 /* SSL3_ST_SEND_xxxxxx_HELLO_B */
1043 return (dtls1_do_write(s, SSL3_RT_HANDSHAKE));
1047 * for these 2 messages, we need to
1048 * ssl->enc_read_ctx re-init
1049 * ssl->s3->read_sequence zero
1050 * ssl->s3->read_mac_secret re-init
1051 * ssl->session->read_sym_enc assign
1052 * ssl->session->read_compression assign
1053 * ssl->session->read_hash assign
1055 int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
1059 if (s->state == a) {
1060 p = (unsigned char *)s->init_buf->data;
1062 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1063 s->init_num = DTLS1_CCS_HEADER_LENGTH;
1065 if (s->version == DTLS1_BAD_VER) {
1066 s->d1->next_handshake_write_seq++;
1067 s2n(s->d1->handshake_write_seq, p);
1073 dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
1074 s->d1->handshake_write_seq, 0, 0);
1076 /* buffer the message to handle re-xmits */
1077 dtls1_buffer_message(s, 1);
1082 /* SSL3_ST_CW_CHANGE_B */
1083 return (dtls1_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC));
1086 static int dtls1_add_cert_to_buf(BUF_MEM *buf, unsigned long *l, X509 *x)
1091 n = i2d_X509(x, NULL);
1092 if (!BUF_MEM_grow_clean(buf, (int)(n + (*l) + 3))) {
1093 SSLerr(SSL_F_DTLS1_ADD_CERT_TO_BUF, ERR_R_BUF_LIB);
1096 p = (unsigned char *)&(buf->data[*l]);
1104 unsigned long dtls1_output_cert_chain(SSL *s, X509 *x)
1108 unsigned long l = 3 + DTLS1_HM_HEADER_LENGTH;
1111 /* TLSv1 sends a chain with nothing in it, instead of an alert */
1113 if (!BUF_MEM_grow_clean(buf, 10)) {
1114 SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN, ERR_R_BUF_LIB);
1118 X509_STORE_CTX xs_ctx;
1120 if (!X509_STORE_CTX_init(&xs_ctx, s->ctx->cert_store, x, NULL)) {
1121 SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN, ERR_R_X509_LIB);
1125 X509_verify_cert(&xs_ctx);
1126 /* Don't leave errors in the queue */
1128 for (i = 0; i < sk_X509_num(xs_ctx.chain); i++) {
1129 x = sk_X509_value(xs_ctx.chain, i);
1131 if (!dtls1_add_cert_to_buf(buf, &l, x)) {
1132 X509_STORE_CTX_cleanup(&xs_ctx);
1136 X509_STORE_CTX_cleanup(&xs_ctx);
1138 /* Thawte special :-) */
1139 for (i = 0; i < sk_X509_num(s->ctx->extra_certs); i++) {
1140 x = sk_X509_value(s->ctx->extra_certs, i);
1141 if (!dtls1_add_cert_to_buf(buf, &l, x))
1145 l -= (3 + DTLS1_HM_HEADER_LENGTH);
1147 p = (unsigned char *)&(buf->data[DTLS1_HM_HEADER_LENGTH]);
1150 p = (unsigned char *)&(buf->data[0]);
1151 p = dtls1_set_message_header(s, p, SSL3_MT_CERTIFICATE, l, 0, l);
1153 l += DTLS1_HM_HEADER_LENGTH;
1157 int dtls1_read_failed(SSL *s, int code)
1160 fprintf(stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
1164 if (!dtls1_is_timer_expired(s)) {
1166 * not a timeout, none of our business, let higher layers handle
1167 * this. in fact it's probably an error
1171 #ifndef OPENSSL_NO_HEARTBEATS
1172 /* done, no need to send a retransmit */
1173 if (!SSL_in_init(s) && !s->tlsext_hb_pending)
1175 /* done, no need to send a retransmit */
1176 if (!SSL_in_init(s))
1179 BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
1182 #if 0 /* for now, each alert contains only one
1184 item = pqueue_peek(state->rcvd_records);
1186 /* send an alert immediately for all the missing records */
1190 #if 0 /* no more alert sending, just retransmit the
1191 * last set of messages */
1192 if (state->timeout.read_timeouts >= DTLS1_TMO_READ_COUNT)
1193 ssl3_send_alert(s, SSL3_AL_WARNING,
1194 DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
1197 return dtls1_handle_timeout(s);
1200 int dtls1_get_queue_priority(unsigned short seq, int is_ccs)
1203 * The index of the retransmission queue actually is the message sequence
1204 * number, since the queue only contains messages of a single handshake.
1205 * However, the ChangeCipherSpec has no message sequence number and so
1206 * using only the sequence will result in the CCS and Finished having the
1207 * same index. To prevent this, the sequence number is multiplied by 2.
1208 * In case of a CCS 1 is subtracted. This does not only differ CSS and
1209 * Finished, it also maintains the order of the index (important for
1210 * priority queues) and fits in the unsigned short variable.
1212 return seq * 2 - is_ccs;
1215 int dtls1_retransmit_buffered_messages(SSL *s)
1217 pqueue sent = s->d1->sent_messages;
1223 iter = pqueue_iterator(sent);
1225 for (item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter)) {
1226 frag = (hm_fragment *)item->data;
1227 if (dtls1_retransmit_message(s, (unsigned short)
1228 dtls1_get_queue_priority
1229 (frag->msg_header.seq,
1230 frag->msg_header.is_ccs), 0,
1231 &found) <= 0 && found) {
1232 fprintf(stderr, "dtls1_retransmit_message() failed\n");
1240 int dtls1_buffer_message(SSL *s, int is_ccs)
1244 unsigned char seq64be[8];
1247 * this function is called immediately after a message has been
1250 OPENSSL_assert(s->init_off == 0);
1252 frag = dtls1_hm_fragment_new(s->init_num, 0);
1256 memcpy(frag->fragment, s->init_buf->data, s->init_num);
1259 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1261 DTLS1_VERSION) ? DTLS1_CCS_HEADER_LENGTH : 3) ==
1262 (unsigned int)s->init_num);
1264 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1265 DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num);
1268 frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
1269 frag->msg_header.seq = s->d1->w_msg_hdr.seq;
1270 frag->msg_header.type = s->d1->w_msg_hdr.type;
1271 frag->msg_header.frag_off = 0;
1272 frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
1273 frag->msg_header.is_ccs = is_ccs;
1275 /* save current state */
1276 frag->msg_header.saved_retransmit_state.enc_write_ctx = s->enc_write_ctx;
1277 frag->msg_header.saved_retransmit_state.write_hash = s->write_hash;
1278 frag->msg_header.saved_retransmit_state.compress = s->compress;
1279 frag->msg_header.saved_retransmit_state.session = s->session;
1280 frag->msg_header.saved_retransmit_state.epoch = s->d1->w_epoch;
1282 memset(seq64be, 0, sizeof(seq64be));
1285 char)(dtls1_get_queue_priority(frag->msg_header.seq,
1286 frag->msg_header.is_ccs) >> 8);
1289 char)(dtls1_get_queue_priority(frag->msg_header.seq,
1290 frag->msg_header.is_ccs));
1292 item = pitem_new(seq64be, frag);
1294 dtls1_hm_fragment_free(frag);
1298 fprintf(stderr, "buffered messge: \ttype = %xx\n", msg_buf->type);
1299 fprintf(stderr, "\t\t\t\t\tlen = %d\n", msg_buf->len);
1300 fprintf(stderr, "\t\t\t\t\tseq_num = %d\n", msg_buf->seq_num);
1303 pqueue_insert(s->d1->sent_messages, item);
1308 dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
1312 /* XDTLS: for now assuming that read/writes are blocking */
1315 unsigned long header_length;
1316 unsigned char seq64be[8];
1317 struct dtls1_retransmit_state saved_state;
1318 unsigned char save_write_sequence[8];
1321 OPENSSL_assert(s->init_num == 0);
1322 OPENSSL_assert(s->init_off == 0);
1325 /* XDTLS: the requested message ought to be found, otherwise error */
1326 memset(seq64be, 0, sizeof(seq64be));
1327 seq64be[6] = (unsigned char)(seq >> 8);
1328 seq64be[7] = (unsigned char)seq;
1330 item = pqueue_find(s->d1->sent_messages, seq64be);
1332 fprintf(stderr, "retransmit: message %d non-existant\n", seq);
1338 frag = (hm_fragment *)item->data;
1340 if (frag->msg_header.is_ccs)
1341 header_length = DTLS1_CCS_HEADER_LENGTH;
1343 header_length = DTLS1_HM_HEADER_LENGTH;
1345 memcpy(s->init_buf->data, frag->fragment,
1346 frag->msg_header.msg_len + header_length);
1347 s->init_num = frag->msg_header.msg_len + header_length;
1349 dtls1_set_message_header_int(s, frag->msg_header.type,
1350 frag->msg_header.msg_len,
1351 frag->msg_header.seq, 0,
1352 frag->msg_header.frag_len);
1354 /* save current state */
1355 saved_state.enc_write_ctx = s->enc_write_ctx;
1356 saved_state.write_hash = s->write_hash;
1357 saved_state.compress = s->compress;
1358 saved_state.session = s->session;
1359 saved_state.epoch = s->d1->w_epoch;
1360 saved_state.epoch = s->d1->w_epoch;
1362 s->d1->retransmitting = 1;
1364 /* restore state in which the message was originally sent */
1365 s->enc_write_ctx = frag->msg_header.saved_retransmit_state.enc_write_ctx;
1366 s->write_hash = frag->msg_header.saved_retransmit_state.write_hash;
1367 s->compress = frag->msg_header.saved_retransmit_state.compress;
1368 s->session = frag->msg_header.saved_retransmit_state.session;
1369 s->d1->w_epoch = frag->msg_header.saved_retransmit_state.epoch;
1371 if (frag->msg_header.saved_retransmit_state.epoch ==
1372 saved_state.epoch - 1) {
1373 memcpy(save_write_sequence, s->s3->write_sequence,
1374 sizeof(s->s3->write_sequence));
1375 memcpy(s->s3->write_sequence, s->d1->last_write_sequence,
1376 sizeof(s->s3->write_sequence));
1379 ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1380 SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1382 /* restore current state */
1383 s->enc_write_ctx = saved_state.enc_write_ctx;
1384 s->write_hash = saved_state.write_hash;
1385 s->compress = saved_state.compress;
1386 s->session = saved_state.session;
1387 s->d1->w_epoch = saved_state.epoch;
1389 if (frag->msg_header.saved_retransmit_state.epoch ==
1390 saved_state.epoch - 1) {
1391 memcpy(s->d1->last_write_sequence, s->s3->write_sequence,
1392 sizeof(s->s3->write_sequence));
1393 memcpy(s->s3->write_sequence, save_write_sequence,
1394 sizeof(s->s3->write_sequence));
1397 s->d1->retransmitting = 0;
1399 (void)BIO_flush(SSL_get_wbio(s));
1403 unsigned char *dtls1_set_message_header(SSL *s, unsigned char *p,
1404 unsigned char mt, unsigned long len,
1405 unsigned long frag_off,
1406 unsigned long frag_len)
1408 /* Don't change sequence numbers while listening */
1409 if (frag_off == 0 && !s->d1->listen) {
1410 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1411 s->d1->next_handshake_write_seq++;
1414 dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1415 frag_off, frag_len);
1417 return p += DTLS1_HM_HEADER_LENGTH;
1420 /* don't actually do the writing, wait till the MTU has been retrieved */
1422 dtls1_set_message_header_int(SSL *s, unsigned char mt,
1423 unsigned long len, unsigned short seq_num,
1424 unsigned long frag_off, unsigned long frag_len)
1426 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1429 msg_hdr->msg_len = len;
1430 msg_hdr->seq = seq_num;
1431 msg_hdr->frag_off = frag_off;
1432 msg_hdr->frag_len = frag_len;
1436 dtls1_fix_message_header(SSL *s, unsigned long frag_off,
1437 unsigned long frag_len)
1439 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1441 msg_hdr->frag_off = frag_off;
1442 msg_hdr->frag_len = frag_len;
1445 static unsigned char *dtls1_write_message_header(SSL *s, unsigned char *p)
1447 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1449 *p++ = msg_hdr->type;
1450 l2n3(msg_hdr->msg_len, p);
1452 s2n(msg_hdr->seq, p);
1453 l2n3(msg_hdr->frag_off, p);
1454 l2n3(msg_hdr->frag_len, p);
1459 unsigned int dtls1_link_min_mtu(void)
1461 return (g_probable_mtu[(sizeof(g_probable_mtu) /
1462 sizeof(g_probable_mtu[0])) - 1]);
1465 unsigned int dtls1_min_mtu(SSL *s)
1467 return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
1471 dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
1473 memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
1474 msg_hdr->type = *(data++);
1475 n2l3(data, msg_hdr->msg_len);
1477 n2s(data, msg_hdr->seq);
1478 n2l3(data, msg_hdr->frag_off);
1479 n2l3(data, msg_hdr->frag_len);
1482 void dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr)
1484 memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st));
1486 ccs_hdr->type = *(data++);
1489 int dtls1_shutdown(SSL *s)
1492 #ifndef OPENSSL_NO_SCTP
1493 if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
1494 !(s->shutdown & SSL_SENT_SHUTDOWN)) {
1495 ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
1500 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1,
1504 ret = ssl3_shutdown(s);
1505 #ifndef OPENSSL_NO_SCTP
1506 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
1511 #ifndef OPENSSL_NO_HEARTBEATS
1512 int dtls1_process_heartbeat(SSL *s)
1514 unsigned char *p = &s->s3->rrec.data[0], *pl;
1515 unsigned short hbtype;
1516 unsigned int payload;
1517 unsigned int padding = 16; /* Use minimum padding */
1519 if (s->msg_callback)
1520 s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
1521 &s->s3->rrec.data[0], s->s3->rrec.length,
1522 s, s->msg_callback_arg);
1524 /* Read type and payload length first */
1525 if (1 + 2 + 16 > s->s3->rrec.length)
1526 return 0; /* silently discard */
1527 if (s->s3->rrec.length > SSL3_RT_MAX_PLAIN_LENGTH)
1528 return 0; /* silently discard per RFC 6520 sec. 4 */
1532 if (1 + 2 + payload + 16 > s->s3->rrec.length)
1533 return 0; /* silently discard per RFC 6520 sec. 4 */
1536 if (hbtype == TLS1_HB_REQUEST) {
1537 unsigned char *buffer, *bp;
1538 unsigned int write_length = 1 /* heartbeat type */ +
1539 2 /* heartbeat length */ +
1543 if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
1547 * Allocate memory for the response, size is 1 byte message type,
1548 * plus 2 bytes payload length, plus payload, plus padding
1550 buffer = OPENSSL_malloc(write_length);
1553 /* Enter response type, length and copy payload */
1554 *bp++ = TLS1_HB_RESPONSE;
1556 memcpy(bp, pl, payload);
1558 /* Random padding */
1559 if (RAND_pseudo_bytes(bp, padding) < 0) {
1560 OPENSSL_free(buffer);
1564 r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, write_length);
1566 if (r >= 0 && s->msg_callback)
1567 s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1568 buffer, write_length, s, s->msg_callback_arg);
1570 OPENSSL_free(buffer);
1574 } else if (hbtype == TLS1_HB_RESPONSE) {
1578 * We only send sequence numbers (2 bytes unsigned int), and 16
1579 * random bytes, so we just try to read the sequence number
1583 if (payload == 18 && seq == s->tlsext_hb_seq) {
1584 dtls1_stop_timer(s);
1586 s->tlsext_hb_pending = 0;
1593 int dtls1_heartbeat(SSL *s)
1595 unsigned char *buf, *p;
1597 unsigned int payload = 18; /* Sequence number + random bytes */
1598 unsigned int padding = 16; /* Use minimum padding */
1600 /* Only send if peer supports and accepts HB requests... */
1601 if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
1602 s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS) {
1603 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
1607 /* ...and there is none in flight yet... */
1608 if (s->tlsext_hb_pending) {
1609 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PENDING);
1613 /* ...and no handshake in progress. */
1614 if (SSL_in_init(s) || s->in_handshake) {
1615 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_UNEXPECTED_MESSAGE);
1620 * Check if padding is too long, payload and padding must not exceed 2^14
1621 * - 3 = 16381 bytes in total.
1623 OPENSSL_assert(payload + padding <= 16381);
1626 * Create HeartBeat message, we just use a sequence number
1627 * as payload to distuingish different messages and add
1628 * some random stuff.
1629 * - Message Type, 1 byte
1630 * - Payload Length, 2 bytes (unsigned int)
1631 * - Payload, the sequence number (2 bytes uint)
1632 * - Payload, random bytes (16 bytes uint)
1635 buf = OPENSSL_malloc(1 + 2 + payload + padding);
1638 *p++ = TLS1_HB_REQUEST;
1639 /* Payload length (18 bytes here) */
1641 /* Sequence number */
1642 s2n(s->tlsext_hb_seq, p);
1643 /* 16 random bytes */
1644 if (RAND_pseudo_bytes(p, 16) < 0)
1647 /* Random padding */
1648 if (RAND_pseudo_bytes(p, padding) < 0)
1651 ret = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buf, 3 + payload + padding);
1653 if (s->msg_callback)
1654 s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1655 buf, 3 + payload + padding,
1656 s, s->msg_callback_arg);
1658 dtls1_start_timer(s);
1659 s->tlsext_hb_pending = 1;