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; } }
147 static unsigned char bitmask_start_values[] =
148 { 0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80 };
149 static unsigned char bitmask_end_values[] =
150 { 0xff, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f };
152 /* XDTLS: figure out the right values */
153 static const unsigned int g_probable_mtu[] = { 1500, 512, 256 };
155 static void dtls1_fix_message_header(SSL *s, unsigned long frag_off,
156 unsigned long frag_len);
157 static unsigned char *dtls1_write_message_header(SSL *s, unsigned char *p);
158 static void dtls1_set_message_header_int(SSL *s, unsigned char mt,
160 unsigned short seq_num,
161 unsigned long frag_off,
162 unsigned long frag_len);
163 static long dtls1_get_message_fragment(SSL *s, int st1, int stn, int mt,
165 static int dtls_get_reassembled_message(SSL *s, long *len);
167 static hm_fragment *dtls1_hm_fragment_new(unsigned long frag_len,
170 hm_fragment *frag = NULL;
171 unsigned char *buf = NULL;
172 unsigned char *bitmask = NULL;
174 frag = OPENSSL_malloc(sizeof(*frag));
179 buf = OPENSSL_malloc(frag_len);
186 /* zero length fragment gets zero frag->fragment */
187 frag->fragment = buf;
189 /* Initialize reassembly bitmask if necessary */
191 bitmask = OPENSSL_zalloc(RSMBLY_BITMASK_SIZE(frag_len));
192 if (bitmask == NULL) {
199 frag->reassembly = bitmask;
204 void dtls1_hm_fragment_free(hm_fragment *frag)
208 if (frag->msg_header.is_ccs) {
209 EVP_CIPHER_CTX_free(frag->msg_header.
210 saved_retransmit_state.enc_write_ctx);
211 EVP_MD_CTX_destroy(frag->msg_header.
212 saved_retransmit_state.write_hash);
214 OPENSSL_free(frag->fragment);
215 OPENSSL_free(frag->reassembly);
219 static int dtls1_query_mtu(SSL *s)
221 if (s->d1->link_mtu) {
223 s->d1->link_mtu - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
227 /* AHA! Figure out the MTU, and stick to the right size */
228 if (s->d1->mtu < dtls1_min_mtu(s)) {
229 if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
231 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
234 * I've seen the kernel return bogus numbers when it doesn't know
235 * (initial write), so just make sure we have a reasonable number
237 if (s->d1->mtu < dtls1_min_mtu(s)) {
239 s->d1->mtu = dtls1_min_mtu(s);
240 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
250 * send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or
251 * SSL3_RT_CHANGE_CIPHER_SPEC)
253 int dtls1_do_write(SSL *s, int type)
256 unsigned int curr_mtu;
258 unsigned int len, frag_off, mac_size, blocksize, used_len;
260 if (!dtls1_query_mtu(s))
263 OPENSSL_assert(s->d1->mtu >= dtls1_min_mtu(s)); /* should have something
266 if (s->init_off == 0 && type == SSL3_RT_HANDSHAKE)
267 OPENSSL_assert(s->init_num ==
268 (int)s->d1->w_msg_hdr.msg_len +
269 DTLS1_HM_HEADER_LENGTH);
273 && ((EVP_CIPHER_CTX_mode(s->enc_write_ctx) == EVP_CIPH_GCM_MODE) ||
274 (EVP_CIPHER_CTX_mode(s->enc_write_ctx) == EVP_CIPH_CCM_MODE)))
277 mac_size = EVP_MD_CTX_size(s->write_hash);
281 if (s->enc_write_ctx &&
282 (EVP_CIPHER_CTX_mode(s->enc_write_ctx) == EVP_CIPH_CBC_MODE))
283 blocksize = 2 * EVP_CIPHER_block_size(s->enc_write_ctx->cipher);
288 /* s->init_num shouldn't ever be < 0...but just in case */
289 while (s->init_num > 0) {
290 used_len = BIO_wpending(SSL_get_wbio(s)) + DTLS1_RT_HEADER_LENGTH
291 + mac_size + blocksize;
292 if (s->d1->mtu > used_len)
293 curr_mtu = s->d1->mtu - used_len;
297 if (curr_mtu <= DTLS1_HM_HEADER_LENGTH) {
299 * grr.. we could get an error if MTU picked was wrong
301 ret = BIO_flush(SSL_get_wbio(s));
304 used_len = DTLS1_RT_HEADER_LENGTH + mac_size + blocksize;
305 if (s->d1->mtu > used_len + DTLS1_HM_HEADER_LENGTH) {
306 curr_mtu = s->d1->mtu - used_len;
308 /* Shouldn't happen */
314 * We just checked that s->init_num > 0 so this cast should be safe
316 if (((unsigned int)s->init_num) > curr_mtu)
321 /* Shouldn't ever happen */
326 * XDTLS: this function is too long. split out the CCS part
328 if (type == SSL3_RT_HANDSHAKE) {
329 if (s->init_off != 0) {
330 OPENSSL_assert(s->init_off > DTLS1_HM_HEADER_LENGTH);
331 s->init_off -= DTLS1_HM_HEADER_LENGTH;
332 s->init_num += DTLS1_HM_HEADER_LENGTH;
335 * We just checked that s->init_num > 0 so this cast should
338 if (((unsigned int)s->init_num) > curr_mtu)
344 /* Shouldn't ever happen */
348 if (len < DTLS1_HM_HEADER_LENGTH) {
350 * len is so small that we really can't do anything sensible
355 dtls1_fix_message_header(s, frag_off,
356 len - DTLS1_HM_HEADER_LENGTH);
358 dtls1_write_message_header(s,
359 (unsigned char *)&s->init_buf->
363 ret = dtls1_write_bytes(s, type, &s->init_buf->data[s->init_off],
367 * might need to update MTU here, but we don't know which
368 * previous packet caused the failure -- so can't really
369 * retransmit anything. continue as if everything is fine and
370 * wait for an alert to handle the retransmit
372 if (retry && BIO_ctrl(SSL_get_wbio(s),
373 BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0) {
374 if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
375 if (!dtls1_query_mtu(s))
377 /* Have one more go */
387 * bad if this assert fails, only part of the handshake message
388 * got sent. but why would this happen?
390 OPENSSL_assert(len == (unsigned int)ret);
392 if (type == SSL3_RT_HANDSHAKE && !s->d1->retransmitting) {
394 * should not be done for 'Hello Request's, but in that case
395 * we'll ignore the result anyway
398 (unsigned char *)&s->init_buf->data[s->init_off];
399 const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
402 if (frag_off == 0 && s->version != DTLS1_BAD_VER) {
404 * reconstruct message header is if it is being sent in
407 *p++ = msg_hdr->type;
408 l2n3(msg_hdr->msg_len, p);
409 s2n(msg_hdr->seq, p);
411 l2n3(msg_hdr->msg_len, p);
412 p -= DTLS1_HM_HEADER_LENGTH;
415 p += DTLS1_HM_HEADER_LENGTH;
416 xlen = ret - DTLS1_HM_HEADER_LENGTH;
419 ssl3_finish_mac(s, p, xlen);
422 if (ret == s->init_num) {
424 s->msg_callback(1, s->version, type, s->init_buf->data,
425 (size_t)(s->init_off + s->init_num), s,
426 s->msg_callback_arg);
428 s->init_off = 0; /* done writing this message */
435 frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
442 * Obtain handshake message of message type 'mt' (any if mt == -1), maximum
443 * acceptable body length 'max'. Read an entire handshake message. Handshake
444 * messages arrive in fragments.
446 long dtls1_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
449 struct hm_header_st *msg_hdr;
451 unsigned long msg_len;
454 * s3->tmp is used to store messages that are unexpected, caused by the
455 * absence of an optional handshake message
457 if (s->s3->tmp.reuse_message) {
458 if ((mt >= 0) && (s->s3->tmp.message_type != mt)) {
459 al = SSL_AD_UNEXPECTED_MESSAGE;
460 SSLerr(SSL_F_DTLS1_GET_MESSAGE, SSL_R_UNEXPECTED_MESSAGE);
467 * Messages reused from dtls1_listen also have the record header in
468 * the buffer which we need to skip over.
470 if (s->s3->tmp.reuse_message == DTLS1_SKIP_RECORD_HEADER) {
471 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH
472 + DTLS1_RT_HEADER_LENGTH;
474 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
476 s->init_num = (int)s->s3->tmp.message_size;
477 s->s3->tmp.reuse_message = 0;
481 msg_hdr = &s->d1->r_msg_hdr;
482 memset(msg_hdr, 0, sizeof(*msg_hdr));
485 i = dtls1_get_message_fragment(s, st1, stn, mt, ok);
486 if (i == DTLS1_HM_BAD_FRAGMENT || i == DTLS1_HM_FRAGMENT_RETRY) {
487 /* bad fragment received */
489 } else if (i <= 0 && !*ok) {
493 if (mt >= 0 && s->s3->tmp.message_type != mt) {
494 al = SSL_AD_UNEXPECTED_MESSAGE;
495 SSLerr(SSL_F_DTLS1_GET_MESSAGE, SSL_R_UNEXPECTED_MESSAGE);
499 p = (unsigned char *)s->init_buf->data;
501 if (mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
502 if (s->msg_callback) {
503 s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC,
504 p, 1, s, s->msg_callback_arg);
507 * This isn't a real handshake message so skip the processing below.
508 * dtls1_get_message_fragment() will never return a CCS if mt == -1,
509 * so we are ok to continue in that case.
514 msg_len = msg_hdr->msg_len;
516 /* reconstruct message header */
517 *(p++) = msg_hdr->type;
519 s2n(msg_hdr->seq, p);
522 if (s->version != DTLS1_BAD_VER) {
523 p -= DTLS1_HM_HEADER_LENGTH;
524 msg_len += DTLS1_HM_HEADER_LENGTH;
527 if (msg_len > (unsigned long)max) {
528 al = SSL_AD_ILLEGAL_PARAMETER;
529 SSLerr(SSL_F_DTLS1_GET_MESSAGE, SSL_R_EXCESSIVE_MESSAGE_SIZE);
533 ssl3_finish_mac(s, p, msg_len);
535 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
536 p, msg_len, s, s->msg_callback_arg);
538 memset(msg_hdr, 0, sizeof(*msg_hdr));
540 s->d1->handshake_read_seq++;
543 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
547 ssl3_send_alert(s, SSL3_AL_FATAL, al);
552 int dtls_get_message(SSL *s, int *mt, unsigned long *len)
554 struct hm_header_st *msg_hdr;
556 unsigned long msg_len;
560 msg_hdr = &s->d1->r_msg_hdr;
561 memset(msg_hdr, 0, sizeof(*msg_hdr));
564 ok = dtls_get_reassembled_message(s, &tmplen);
565 if (tmplen == DTLS1_HM_BAD_FRAGMENT
566 || tmplen == DTLS1_HM_FRAGMENT_RETRY) {
567 /* bad fragment received */
569 } else if (tmplen <= 0 && !ok) {
573 *mt = s->s3->tmp.message_type;
575 p = (unsigned char *)s->init_buf->data;
577 if (*mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
578 if (s->msg_callback) {
579 s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC,
580 p, 1, s, s->msg_callback_arg);
583 * This isn't a real handshake message so skip the processing below.
585 *len = (unsigned long)tmplen;
589 msg_len = msg_hdr->msg_len;
591 /* reconstruct message header */
592 *(p++) = msg_hdr->type;
594 s2n(msg_hdr->seq, p);
597 if (s->version != DTLS1_BAD_VER) {
598 p -= DTLS1_HM_HEADER_LENGTH;
599 msg_len += DTLS1_HM_HEADER_LENGTH;
602 ssl3_finish_mac(s, p, msg_len);
604 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
605 p, msg_len, s, s->msg_callback_arg);
607 memset(msg_hdr, 0, sizeof(*msg_hdr));
609 s->d1->handshake_read_seq++;
612 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
618 static int dtls1_preprocess_fragment(SSL *s, struct hm_header_st *msg_hdr)
620 size_t frag_off, frag_len, msg_len;
622 msg_len = msg_hdr->msg_len;
623 frag_off = msg_hdr->frag_off;
624 frag_len = msg_hdr->frag_len;
626 /* sanity checking */
627 if ((frag_off + frag_len) > msg_len) {
628 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT, SSL_R_EXCESSIVE_MESSAGE_SIZE);
629 return SSL_AD_ILLEGAL_PARAMETER;
632 if (s->d1->r_msg_hdr.frag_off == 0) { /* first fragment */
634 * msg_len is limited to 2^24, but is effectively checked against max
637 if (!BUF_MEM_grow_clean
638 (s->init_buf, msg_len + DTLS1_HM_HEADER_LENGTH)) {
639 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT, ERR_R_BUF_LIB);
640 return SSL_AD_INTERNAL_ERROR;
643 s->s3->tmp.message_size = msg_len;
644 s->d1->r_msg_hdr.msg_len = msg_len;
645 s->s3->tmp.message_type = msg_hdr->type;
646 s->d1->r_msg_hdr.type = msg_hdr->type;
647 s->d1->r_msg_hdr.seq = msg_hdr->seq;
648 } else if (msg_len != s->d1->r_msg_hdr.msg_len) {
650 * They must be playing with us! BTW, failure to enforce upper limit
651 * would open possibility for buffer overrun.
653 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT, SSL_R_EXCESSIVE_MESSAGE_SIZE);
654 return SSL_AD_ILLEGAL_PARAMETER;
657 return 0; /* no error */
660 static int dtls1_retrieve_buffered_fragment(SSL *s, int *ok)
663 * (0) check whether the desired fragment is available
665 * (1) copy over the fragment to s->init_buf->data[]
666 * (2) update s->init_num
673 item = pqueue_peek(s->d1->buffered_messages);
677 frag = (hm_fragment *)item->data;
679 /* Don't return if reassembly still in progress */
680 if (frag->reassembly != NULL)
683 if (s->d1->handshake_read_seq == frag->msg_header.seq) {
684 unsigned long frag_len = frag->msg_header.frag_len;
685 pqueue_pop(s->d1->buffered_messages);
687 al = dtls1_preprocess_fragment(s, &frag->msg_header);
689 if (al == 0) { /* no alert */
691 (unsigned char *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
692 memcpy(&p[frag->msg_header.frag_off], frag->fragment,
693 frag->msg_header.frag_len);
696 dtls1_hm_fragment_free(frag);
704 ssl3_send_alert(s, SSL3_AL_FATAL, al);
713 * dtls1_max_handshake_message_len returns the maximum number of bytes
714 * permitted in a DTLS handshake message for |s|. The minimum is 16KB, but
715 * may be greater if the maximum certificate list size requires it.
717 static unsigned long dtls1_max_handshake_message_len(const SSL *s)
719 unsigned long max_len =
720 DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
721 if (max_len < (unsigned long)s->max_cert_list)
722 return s->max_cert_list;
727 dtls1_reassemble_fragment(SSL *s, const struct hm_header_st *msg_hdr, int *ok)
729 hm_fragment *frag = NULL;
731 int i = -1, is_complete;
732 unsigned char seq64be[8];
733 unsigned long frag_len = msg_hdr->frag_len;
735 if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len ||
736 msg_hdr->msg_len > dtls1_max_handshake_message_len(s))
740 return DTLS1_HM_FRAGMENT_RETRY;
742 /* Try to find item in queue */
743 memset(seq64be, 0, sizeof(seq64be));
744 seq64be[6] = (unsigned char)(msg_hdr->seq >> 8);
745 seq64be[7] = (unsigned char)msg_hdr->seq;
746 item = pqueue_find(s->d1->buffered_messages, seq64be);
749 frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1);
752 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
753 frag->msg_header.frag_len = frag->msg_header.msg_len;
754 frag->msg_header.frag_off = 0;
756 frag = (hm_fragment *)item->data;
757 if (frag->msg_header.msg_len != msg_hdr->msg_len) {
765 * If message is already reassembled, this must be a retransmit and can
766 * be dropped. In this case item != NULL and so frag does not need to be
769 if (frag->reassembly == NULL) {
770 unsigned char devnull[256];
773 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, NULL,
776 sizeof(devnull) ? sizeof(devnull) :
782 return DTLS1_HM_FRAGMENT_RETRY;
785 /* read the body of the fragment (header has already been read */
786 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, NULL,
787 frag->fragment + msg_hdr->frag_off,
789 if ((unsigned long)i != frag_len)
794 RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off,
795 (long)(msg_hdr->frag_off + frag_len));
797 RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len,
801 OPENSSL_free(frag->reassembly);
802 frag->reassembly = NULL;
806 item = pitem_new(seq64be, frag);
812 item = pqueue_insert(s->d1->buffered_messages, item);
814 * pqueue_insert fails iff a duplicate item is inserted. However,
815 * |item| cannot be a duplicate. If it were, |pqueue_find|, above,
816 * would have returned it and control would never have reached this
819 OPENSSL_assert(item != NULL);
822 return DTLS1_HM_FRAGMENT_RETRY;
826 dtls1_hm_fragment_free(frag);
832 dtls1_process_out_of_seq_message(SSL *s, const struct hm_header_st *msg_hdr,
836 hm_fragment *frag = NULL;
838 unsigned char seq64be[8];
839 unsigned long frag_len = msg_hdr->frag_len;
841 if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len)
844 /* Try to find item in queue, to prevent duplicate entries */
845 memset(seq64be, 0, sizeof(seq64be));
846 seq64be[6] = (unsigned char)(msg_hdr->seq >> 8);
847 seq64be[7] = (unsigned char)msg_hdr->seq;
848 item = pqueue_find(s->d1->buffered_messages, seq64be);
851 * If we already have an entry and this one is a fragment, don't discard
852 * it and rather try to reassemble it.
854 if (item != NULL && frag_len != msg_hdr->msg_len)
858 * Discard the message if sequence number was already there, is too far
859 * in the future, already in the queue or if we received a FINISHED
860 * before the SERVER_HELLO, which then must be a stale retransmit.
862 if (msg_hdr->seq <= s->d1->handshake_read_seq ||
863 msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL ||
864 (s->d1->handshake_read_seq == 0 && msg_hdr->type == SSL3_MT_FINISHED))
866 unsigned char devnull[256];
869 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, NULL,
872 sizeof(devnull) ? sizeof(devnull) :
879 if (frag_len != msg_hdr->msg_len)
880 return dtls1_reassemble_fragment(s, msg_hdr, ok);
882 if (frag_len > dtls1_max_handshake_message_len(s))
885 frag = dtls1_hm_fragment_new(frag_len, 0);
889 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
893 * read the body of the fragment (header has already been read
895 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, NULL,
896 frag->fragment, frag_len, 0);
897 if ((unsigned long)i != frag_len)
903 item = pitem_new(seq64be, frag);
907 item = pqueue_insert(s->d1->buffered_messages, item);
909 * pqueue_insert fails iff a duplicate item is inserted. However,
910 * |item| cannot be a duplicate. If it were, |pqueue_find|, above,
911 * would have returned it. Then, either |frag_len| !=
912 * |msg_hdr->msg_len| in which case |item| is set to NULL and it will
913 * have been processed with |dtls1_reassemble_fragment|, above, or
914 * the record will have been discarded.
916 OPENSSL_assert(item != NULL);
919 return DTLS1_HM_FRAGMENT_RETRY;
923 dtls1_hm_fragment_free(frag);
929 dtls1_get_message_fragment(SSL *s, int st1, int stn, int mt, int *ok)
934 *ok = dtls_get_reassembled_message(s, &len);
935 /* A CCS isn't a real handshake message, so if we get one there is no
936 * message sequence number to give us confidence that this was really
937 * intended to be at this point in the handshake sequence. Therefore we
938 * only allow this if we were explicitly looking for it (i.e. if |mt|
939 * is -1 we still don't allow it). If we get one when we're not
940 * expecting it then probably something got re-ordered or this is a
941 * retransmit. We should drop this and try again.
943 } while (*ok && mt != SSL3_MT_CHANGE_CIPHER_SPEC
944 && s->s3->tmp.message_type == SSL3_MT_CHANGE_CIPHER_SPEC);
952 static int dtls_get_reassembled_message(SSL *s, long *len)
954 unsigned char wire[DTLS1_HM_HEADER_LENGTH];
955 unsigned long mlen, frag_off, frag_len;
956 int i, al, recvd_type;
957 struct hm_header_st msg_hdr;
961 /* see if we have the required fragment already */
962 if ((frag_len = dtls1_retrieve_buffered_fragment(s, &ok)) || ok) {
964 s->init_num = frag_len;
969 /* read handshake message header */
970 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, &recvd_type, wire,
971 DTLS1_HM_HEADER_LENGTH, 0);
972 if (i <= 0) { /* nbio, or an error */
973 s->rwstate = SSL_READING;
977 if(recvd_type == SSL3_RT_CHANGE_CIPHER_SPEC) {
978 if (wire[0] != SSL3_MT_CCS) {
979 al = SSL_AD_UNEXPECTED_MESSAGE;
980 SSLerr(SSL_F_DTLS_GET_REASSEMBLED_MESSAGE,
981 SSL_R_BAD_CHANGE_CIPHER_SPEC);
985 memcpy(s->init_buf->data, wire, i);
987 s->init_msg = s->init_buf->data + 1;
988 s->s3->tmp.message_type = SSL3_MT_CHANGE_CIPHER_SPEC;
989 s->s3->tmp.message_size = i - 1;
994 /* Handshake fails if message header is incomplete */
995 if (i != DTLS1_HM_HEADER_LENGTH) {
996 al = SSL_AD_UNEXPECTED_MESSAGE;
997 SSLerr(SSL_F_DTLS_GET_REASSEMBLED_MESSAGE, SSL_R_UNEXPECTED_MESSAGE);
1001 /* parse the message fragment header */
1002 dtls1_get_message_header(wire, &msg_hdr);
1004 mlen = msg_hdr.msg_len;
1005 frag_off = msg_hdr.frag_off;
1006 frag_len = msg_hdr.frag_len;
1009 * We must have at least frag_len bytes left in the record to be read.
1010 * Fragments must not span records.
1012 if (frag_len > RECORD_LAYER_get_rrec_length(&s->rlayer)) {
1013 al = SSL3_AD_ILLEGAL_PARAMETER;
1014 SSLerr(SSL_F_DTLS_GET_REASSEMBLED_MESSAGE, SSL_R_BAD_LENGTH);
1019 * if this is a future (or stale) message it gets buffered
1020 * (or dropped)--no further processing at this time
1021 * While listening, we accept seq 1 (ClientHello with cookie)
1022 * although we're still expecting seq 0 (ClientHello)
1024 if (msg_hdr.seq != s->d1->handshake_read_seq) {
1025 *len = dtls1_process_out_of_seq_message(s, &msg_hdr, &ok);
1029 if (frag_len && frag_len < mlen) {
1030 *len = dtls1_reassemble_fragment(s, &msg_hdr, &ok);
1034 if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
1035 wire[0] == SSL3_MT_HELLO_REQUEST) {
1037 * The server may always send 'Hello Request' messages -- we are
1038 * doing a handshake anyway now, so ignore them if their format is
1039 * correct. Does not count for 'Finished' MAC.
1041 if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0) {
1042 if (s->msg_callback)
1043 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
1044 wire, DTLS1_HM_HEADER_LENGTH, s,
1045 s->msg_callback_arg);
1049 } else { /* Incorrectly formated Hello request */
1051 al = SSL_AD_UNEXPECTED_MESSAGE;
1052 SSLerr(SSL_F_DTLS_GET_REASSEMBLED_MESSAGE,
1053 SSL_R_UNEXPECTED_MESSAGE);
1058 if ((al = dtls1_preprocess_fragment(s, &msg_hdr)))
1063 (unsigned char *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
1065 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, NULL,
1066 &p[frag_off], frag_len, 0);
1069 * This shouldn't ever fail due to NBIO because we already checked
1070 * that we have enough data in the record
1073 s->rwstate = SSL_READING;
1081 * XDTLS: an incorrectly formatted fragment should cause the handshake
1084 if (i != (int)frag_len) {
1085 al = SSL3_AD_ILLEGAL_PARAMETER;
1086 SSLerr(SSL_F_DTLS_GET_REASSEMBLED_MESSAGE, SSL3_AD_ILLEGAL_PARAMETER);
1091 * Note that s->init_num is *not* used as current offset in
1092 * s->init_buf->data, but as a counter summing up fragments' lengths: as
1093 * soon as they sum up to handshake packet length, we assume we have got
1094 * all the fragments.
1096 *len = s->init_num = frag_len;
1100 ssl3_send_alert(s, SSL3_AL_FATAL, al);
1107 int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
1109 if (s->state == a) {
1110 if (dtls_construct_change_cipher_spec(s) == 0)
1114 /* SSL3_ST_CW_CHANGE_B */
1115 return (dtls1_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC));
1120 * for these 2 messages, we need to
1121 * ssl->enc_read_ctx re-init
1122 * ssl->rlayer.read_sequence zero
1123 * ssl->s3->read_mac_secret re-init
1124 * ssl->session->read_sym_enc assign
1125 * ssl->session->read_compression assign
1126 * ssl->session->read_hash assign
1128 int dtls_construct_change_cipher_spec(SSL *s)
1132 p = (unsigned char *)s->init_buf->data;
1134 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1135 s->init_num = DTLS1_CCS_HEADER_LENGTH;
1137 if (s->version == DTLS1_BAD_VER) {
1138 s->d1->next_handshake_write_seq++;
1139 s2n(s->d1->handshake_write_seq, p);
1145 dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
1146 s->d1->handshake_write_seq, 0, 0);
1148 /* buffer the message to handle re-xmits */
1149 if (!dtls1_buffer_message(s, 1)) {
1150 SSLerr(SSL_F_DTLS_CONSTRUCT_CHANGE_CIPHER_SPEC, ERR_R_INTERNAL_ERROR);
1157 #ifndef OPENSSL_NO_SCTP
1158 enum WORK_STATE dtls_wait_for_dry(SSL *s)
1162 /* read app data until dry event */
1163 ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
1168 s->s3->in_read_app_data = 2;
1169 s->rwstate = SSL_READING;
1170 BIO_clear_retry_flags(SSL_get_rbio(s));
1171 BIO_set_retry_read(SSL_get_rbio(s));
1174 return WORK_FINISHED_CONTINUE;
1178 int dtls1_read_failed(SSL *s, int code)
1181 fprintf(stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
1185 if (!dtls1_is_timer_expired(s)) {
1187 * not a timeout, none of our business, let higher layers handle
1188 * this. in fact it's probably an error
1192 #ifndef OPENSSL_NO_HEARTBEATS
1193 /* done, no need to send a retransmit */
1194 if (!SSL_in_init(s) && !s->tlsext_hb_pending)
1196 /* done, no need to send a retransmit */
1197 if (!SSL_in_init(s))
1200 BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
1204 return dtls1_handle_timeout(s);
1207 int dtls1_get_queue_priority(unsigned short seq, int is_ccs)
1210 * The index of the retransmission queue actually is the message sequence
1211 * number, since the queue only contains messages of a single handshake.
1212 * However, the ChangeCipherSpec has no message sequence number and so
1213 * using only the sequence will result in the CCS and Finished having the
1214 * same index. To prevent this, the sequence number is multiplied by 2.
1215 * In case of a CCS 1 is subtracted. This does not only differ CSS and
1216 * Finished, it also maintains the order of the index (important for
1217 * priority queues) and fits in the unsigned short variable.
1219 return seq * 2 - is_ccs;
1222 int dtls1_retransmit_buffered_messages(SSL *s)
1224 pqueue sent = s->d1->sent_messages;
1230 iter = pqueue_iterator(sent);
1232 for (item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter)) {
1233 frag = (hm_fragment *)item->data;
1234 if (dtls1_retransmit_message(s, (unsigned short)
1235 dtls1_get_queue_priority
1236 (frag->msg_header.seq,
1237 frag->msg_header.is_ccs), 0,
1238 &found) <= 0 && found) {
1239 fprintf(stderr, "dtls1_retransmit_message() failed\n");
1247 int dtls1_buffer_message(SSL *s, int is_ccs)
1251 unsigned char seq64be[8];
1254 * this function is called immediately after a message has been
1257 OPENSSL_assert(s->init_off == 0);
1259 frag = dtls1_hm_fragment_new(s->init_num, 0);
1263 memcpy(frag->fragment, s->init_buf->data, s->init_num);
1266 /* For DTLS1_BAD_VER the header length is non-standard */
1267 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1268 ((s->version==DTLS1_BAD_VER)?3:DTLS1_CCS_HEADER_LENGTH)
1269 == (unsigned int)s->init_num);
1271 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1272 DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num);
1275 frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
1276 frag->msg_header.seq = s->d1->w_msg_hdr.seq;
1277 frag->msg_header.type = s->d1->w_msg_hdr.type;
1278 frag->msg_header.frag_off = 0;
1279 frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
1280 frag->msg_header.is_ccs = is_ccs;
1282 /* save current state */
1283 frag->msg_header.saved_retransmit_state.enc_write_ctx = s->enc_write_ctx;
1284 frag->msg_header.saved_retransmit_state.write_hash = s->write_hash;
1285 frag->msg_header.saved_retransmit_state.compress = s->compress;
1286 frag->msg_header.saved_retransmit_state.session = s->session;
1287 frag->msg_header.saved_retransmit_state.epoch =
1288 DTLS_RECORD_LAYER_get_w_epoch(&s->rlayer);
1290 memset(seq64be, 0, sizeof(seq64be));
1293 char)(dtls1_get_queue_priority(frag->msg_header.seq,
1294 frag->msg_header.is_ccs) >> 8);
1297 char)(dtls1_get_queue_priority(frag->msg_header.seq,
1298 frag->msg_header.is_ccs));
1300 item = pitem_new(seq64be, frag);
1302 dtls1_hm_fragment_free(frag);
1306 pqueue_insert(s->d1->sent_messages, item);
1311 dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
1315 /* XDTLS: for now assuming that read/writes are blocking */
1318 unsigned long header_length;
1319 unsigned char seq64be[8];
1320 struct dtls1_retransmit_state saved_state;
1323 OPENSSL_assert(s->init_num == 0);
1324 OPENSSL_assert(s->init_off == 0);
1327 /* XDTLS: the requested message ought to be found, otherwise error */
1328 memset(seq64be, 0, sizeof(seq64be));
1329 seq64be[6] = (unsigned char)(seq >> 8);
1330 seq64be[7] = (unsigned char)seq;
1332 item = pqueue_find(s->d1->sent_messages, seq64be);
1334 fprintf(stderr, "retransmit: message %d non-existant\n", seq);
1340 frag = (hm_fragment *)item->data;
1342 if (frag->msg_header.is_ccs)
1343 header_length = DTLS1_CCS_HEADER_LENGTH;
1345 header_length = DTLS1_HM_HEADER_LENGTH;
1347 memcpy(s->init_buf->data, frag->fragment,
1348 frag->msg_header.msg_len + header_length);
1349 s->init_num = frag->msg_header.msg_len + header_length;
1351 dtls1_set_message_header_int(s, frag->msg_header.type,
1352 frag->msg_header.msg_len,
1353 frag->msg_header.seq, 0,
1354 frag->msg_header.frag_len);
1356 /* save current state */
1357 saved_state.enc_write_ctx = s->enc_write_ctx;
1358 saved_state.write_hash = s->write_hash;
1359 saved_state.compress = s->compress;
1360 saved_state.session = s->session;
1361 saved_state.epoch = DTLS_RECORD_LAYER_get_w_epoch(&s->rlayer);
1363 s->d1->retransmitting = 1;
1365 /* restore state in which the message was originally sent */
1366 s->enc_write_ctx = frag->msg_header.saved_retransmit_state.enc_write_ctx;
1367 s->write_hash = frag->msg_header.saved_retransmit_state.write_hash;
1368 s->compress = frag->msg_header.saved_retransmit_state.compress;
1369 s->session = frag->msg_header.saved_retransmit_state.session;
1370 DTLS_RECORD_LAYER_set_saved_w_epoch(&s->rlayer,
1371 frag->msg_header.saved_retransmit_state.epoch);
1373 ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1374 SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1376 /* restore current state */
1377 s->enc_write_ctx = saved_state.enc_write_ctx;
1378 s->write_hash = saved_state.write_hash;
1379 s->compress = saved_state.compress;
1380 s->session = saved_state.session;
1381 DTLS_RECORD_LAYER_set_saved_w_epoch(&s->rlayer, saved_state.epoch);
1383 s->d1->retransmitting = 0;
1385 (void)BIO_flush(SSL_get_wbio(s));
1389 /* call this function when the buffered messages are no longer needed */
1390 void dtls1_clear_record_buffer(SSL *s)
1394 for (item = pqueue_pop(s->d1->sent_messages);
1395 item != NULL; item = pqueue_pop(s->d1->sent_messages)) {
1396 dtls1_hm_fragment_free((hm_fragment *)item->data);
1401 void dtls1_set_message_header(SSL *s, unsigned char *p,
1402 unsigned char mt, unsigned long len,
1403 unsigned long frag_off,
1404 unsigned long frag_len)
1406 if (frag_off == 0) {
1407 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1408 s->d1->next_handshake_write_seq++;
1411 dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1412 frag_off, frag_len);
1415 /* don't actually do the writing, wait till the MTU has been retrieved */
1417 dtls1_set_message_header_int(SSL *s, unsigned char mt,
1418 unsigned long len, unsigned short seq_num,
1419 unsigned long frag_off, unsigned long frag_len)
1421 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1424 msg_hdr->msg_len = len;
1425 msg_hdr->seq = seq_num;
1426 msg_hdr->frag_off = frag_off;
1427 msg_hdr->frag_len = frag_len;
1431 dtls1_fix_message_header(SSL *s, unsigned long frag_off,
1432 unsigned long frag_len)
1434 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1436 msg_hdr->frag_off = frag_off;
1437 msg_hdr->frag_len = frag_len;
1440 static unsigned char *dtls1_write_message_header(SSL *s, unsigned char *p)
1442 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1444 *p++ = msg_hdr->type;
1445 l2n3(msg_hdr->msg_len, p);
1447 s2n(msg_hdr->seq, p);
1448 l2n3(msg_hdr->frag_off, p);
1449 l2n3(msg_hdr->frag_len, p);
1454 unsigned int dtls1_link_min_mtu(void)
1456 return (g_probable_mtu[(sizeof(g_probable_mtu) /
1457 sizeof(g_probable_mtu[0])) - 1]);
1460 unsigned int dtls1_min_mtu(SSL *s)
1462 return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
1466 dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
1468 memset(msg_hdr, 0, sizeof(*msg_hdr));
1469 msg_hdr->type = *(data++);
1470 n2l3(data, msg_hdr->msg_len);
1472 n2s(data, msg_hdr->seq);
1473 n2l3(data, msg_hdr->frag_off);
1474 n2l3(data, msg_hdr->frag_len);
1477 int dtls1_shutdown(SSL *s)
1480 #ifndef OPENSSL_NO_SCTP
1483 wbio = SSL_get_wbio(s);
1484 if (wbio != NULL && BIO_dgram_is_sctp(wbio) &&
1485 !(s->shutdown & SSL_SENT_SHUTDOWN)) {
1486 ret = BIO_dgram_sctp_wait_for_dry(wbio);
1491 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1,
1495 ret = ssl3_shutdown(s);
1496 #ifndef OPENSSL_NO_SCTP
1497 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
1502 #ifndef OPENSSL_NO_HEARTBEATS
1503 int dtls1_process_heartbeat(SSL *s, unsigned char *p, unsigned int length)
1506 unsigned short hbtype;
1507 unsigned int payload;
1508 unsigned int padding = 16; /* Use minimum padding */
1510 if (s->msg_callback)
1511 s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
1512 p, length, s, s->msg_callback_arg);
1514 /* Read type and payload length first */
1515 if (1 + 2 + 16 > length)
1516 return 0; /* silently discard */
1517 if (length > SSL3_RT_MAX_PLAIN_LENGTH)
1518 return 0; /* silently discard per RFC 6520 sec. 4 */
1522 if (1 + 2 + payload + 16 > length)
1523 return 0; /* silently discard per RFC 6520 sec. 4 */
1526 if (hbtype == TLS1_HB_REQUEST) {
1527 unsigned char *buffer, *bp;
1528 unsigned int write_length = 1 /* heartbeat type */ +
1529 2 /* heartbeat length */ +
1533 if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
1537 * Allocate memory for the response, size is 1 byte message type,
1538 * plus 2 bytes payload length, plus payload, plus padding
1540 buffer = OPENSSL_malloc(write_length);
1545 /* Enter response type, length and copy payload */
1546 *bp++ = TLS1_HB_RESPONSE;
1548 memcpy(bp, pl, payload);
1550 /* Random padding */
1551 if (RAND_bytes(bp, padding) <= 0) {
1552 OPENSSL_free(buffer);
1556 r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, write_length);
1558 if (r >= 0 && s->msg_callback)
1559 s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1560 buffer, write_length, s, s->msg_callback_arg);
1562 OPENSSL_free(buffer);
1566 } else if (hbtype == TLS1_HB_RESPONSE) {
1570 * We only send sequence numbers (2 bytes unsigned int), and 16
1571 * random bytes, so we just try to read the sequence number
1575 if (payload == 18 && seq == s->tlsext_hb_seq) {
1576 dtls1_stop_timer(s);
1578 s->tlsext_hb_pending = 0;
1585 int dtls1_heartbeat(SSL *s)
1587 unsigned char *buf, *p;
1589 unsigned int payload = 18; /* Sequence number + random bytes */
1590 unsigned int padding = 16; /* Use minimum padding */
1592 /* Only send if peer supports and accepts HB requests... */
1593 if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
1594 s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS) {
1595 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
1599 /* ...and there is none in flight yet... */
1600 if (s->tlsext_hb_pending) {
1601 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PENDING);
1605 /* ...and no handshake in progress. */
1606 if (SSL_in_init(s) || s->in_handshake) {
1607 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_UNEXPECTED_MESSAGE);
1612 * Check if padding is too long, payload and padding must not exceed 2^14
1613 * - 3 = 16381 bytes in total.
1615 OPENSSL_assert(payload + padding <= 16381);
1618 * Create HeartBeat message, we just use a sequence number
1619 * as payload to distuingish different messages and add
1620 * some random stuff.
1621 * - Message Type, 1 byte
1622 * - Payload Length, 2 bytes (unsigned int)
1623 * - Payload, the sequence number (2 bytes uint)
1624 * - Payload, random bytes (16 bytes uint)
1627 buf = OPENSSL_malloc(1 + 2 + payload + padding);
1629 SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_MALLOC_FAILURE);
1634 *p++ = TLS1_HB_REQUEST;
1635 /* Payload length (18 bytes here) */
1637 /* Sequence number */
1638 s2n(s->tlsext_hb_seq, p);
1639 /* 16 random bytes */
1640 if (RAND_bytes(p, 16) <= 0) {
1641 SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_INTERNAL_ERROR);
1645 /* Random padding */
1646 if (RAND_bytes(p, padding) <= 0) {
1647 SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_INTERNAL_ERROR);
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;