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, long max,
166 static hm_fragment *dtls1_hm_fragment_new(unsigned long frag_len,
169 hm_fragment *frag = NULL;
170 unsigned char *buf = NULL;
171 unsigned char *bitmask = NULL;
173 frag = OPENSSL_malloc(sizeof(*frag));
178 buf = OPENSSL_malloc(frag_len);
185 /* zero length fragment gets zero frag->fragment */
186 frag->fragment = buf;
188 /* Initialize reassembly bitmask if necessary */
190 bitmask = OPENSSL_malloc(RSMBLY_BITMASK_SIZE(frag_len));
191 if (bitmask == NULL) {
196 memset(bitmask, 0, RSMBLY_BITMASK_SIZE(frag_len));
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)
276 mac_size = EVP_MD_CTX_size(s->write_hash);
280 if (s->enc_write_ctx &&
281 (EVP_CIPHER_CTX_mode(s->enc_write_ctx) == EVP_CIPH_CBC_MODE))
282 blocksize = 2 * EVP_CIPHER_block_size(s->enc_write_ctx->cipher);
287 /* s->init_num shouldn't ever be < 0...but just in case */
288 while (s->init_num > 0) {
289 used_len = BIO_wpending(SSL_get_wbio(s)) + DTLS1_RT_HEADER_LENGTH
290 + mac_size + blocksize;
291 if (s->d1->mtu > used_len)
292 curr_mtu = s->d1->mtu - used_len;
296 if (curr_mtu <= DTLS1_HM_HEADER_LENGTH) {
298 * grr.. we could get an error if MTU picked was wrong
300 ret = BIO_flush(SSL_get_wbio(s));
303 used_len = DTLS1_RT_HEADER_LENGTH + mac_size + blocksize;
304 if (s->d1->mtu > used_len + DTLS1_HM_HEADER_LENGTH) {
305 curr_mtu = s->d1->mtu - used_len;
307 /* Shouldn't happen */
313 * We just checked that s->init_num > 0 so this cast should be safe
315 if (((unsigned int)s->init_num) > curr_mtu)
320 /* Shouldn't ever happen */
325 * XDTLS: this function is too long. split out the CCS part
327 if (type == SSL3_RT_HANDSHAKE) {
328 if (s->init_off != 0) {
329 OPENSSL_assert(s->init_off > DTLS1_HM_HEADER_LENGTH);
330 s->init_off -= DTLS1_HM_HEADER_LENGTH;
331 s->init_num += DTLS1_HM_HEADER_LENGTH;
334 * We just checked that s->init_num > 0 so this cast should
337 if (((unsigned int)s->init_num) > curr_mtu)
343 /* Shouldn't ever happen */
347 if (len < DTLS1_HM_HEADER_LENGTH) {
349 * len is so small that we really can't do anything sensible
354 dtls1_fix_message_header(s, frag_off,
355 len - DTLS1_HM_HEADER_LENGTH);
357 dtls1_write_message_header(s,
358 (unsigned char *)&s->init_buf->
362 ret = dtls1_write_bytes(s, type, &s->init_buf->data[s->init_off],
366 * might need to update MTU here, but we don't know which
367 * previous packet caused the failure -- so can't really
368 * retransmit anything. continue as if everything is fine and
369 * wait for an alert to handle the retransmit
371 if (retry && BIO_ctrl(SSL_get_wbio(s),
372 BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0) {
373 if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
374 if (!dtls1_query_mtu(s))
376 /* Have one more go */
386 * bad if this assert fails, only part of the handshake message
387 * got sent. but why would this happen?
389 OPENSSL_assert(len == (unsigned int)ret);
391 if (type == SSL3_RT_HANDSHAKE && !s->d1->retransmitting) {
393 * should not be done for 'Hello Request's, but in that case
394 * we'll ignore the result anyway
397 (unsigned char *)&s->init_buf->data[s->init_off];
398 const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
401 if (frag_off == 0 && s->version != DTLS1_BAD_VER) {
403 * reconstruct message header is if it is being sent in
406 *p++ = msg_hdr->type;
407 l2n3(msg_hdr->msg_len, p);
408 s2n(msg_hdr->seq, p);
410 l2n3(msg_hdr->msg_len, p);
411 p -= DTLS1_HM_HEADER_LENGTH;
414 p += DTLS1_HM_HEADER_LENGTH;
415 xlen = ret - DTLS1_HM_HEADER_LENGTH;
418 ssl3_finish_mac(s, p, xlen);
421 if (ret == s->init_num) {
423 s->msg_callback(1, s->version, type, s->init_buf->data,
424 (size_t)(s->init_off + s->init_num), s,
425 s->msg_callback_arg);
427 s->init_off = 0; /* done writing this message */
434 frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
441 * Obtain handshake message of message type 'mt' (any if mt == -1), maximum
442 * acceptable body length 'max'. Read an entire handshake message. Handshake
443 * messages arrive in fragments.
445 long dtls1_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
448 struct hm_header_st *msg_hdr;
450 unsigned long msg_len;
453 * s3->tmp is used to store messages that are unexpected, caused by the
454 * absence of an optional handshake message
456 if (s->s3->tmp.reuse_message) {
457 s->s3->tmp.reuse_message = 0;
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);
464 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
465 s->init_num = (int)s->s3->tmp.message_size;
469 msg_hdr = &s->d1->r_msg_hdr;
470 memset(msg_hdr, 0, sizeof(*msg_hdr));
473 i = dtls1_get_message_fragment(s, st1, stn, max, ok);
474 if (i == DTLS1_HM_BAD_FRAGMENT || i == DTLS1_HM_FRAGMENT_RETRY) {
475 /* bad fragment received */
477 } else if (i <= 0 && !*ok) {
481 if (mt >= 0 && s->s3->tmp.message_type != mt) {
482 al = SSL_AD_UNEXPECTED_MESSAGE;
483 SSLerr(SSL_F_DTLS1_GET_MESSAGE, SSL_R_UNEXPECTED_MESSAGE);
487 p = (unsigned char *)s->init_buf->data;
488 msg_len = msg_hdr->msg_len;
490 /* reconstruct message header */
491 *(p++) = msg_hdr->type;
493 s2n(msg_hdr->seq, p);
496 if (s->version != DTLS1_BAD_VER) {
497 p -= DTLS1_HM_HEADER_LENGTH;
498 msg_len += DTLS1_HM_HEADER_LENGTH;
501 ssl3_finish_mac(s, p, msg_len);
503 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
504 p, msg_len, s, s->msg_callback_arg);
506 memset(msg_hdr, 0, sizeof(*msg_hdr));
508 /* Don't change sequence numbers while listening */
510 s->d1->handshake_read_seq++;
512 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
516 ssl3_send_alert(s, SSL3_AL_FATAL, al);
521 static int dtls1_preprocess_fragment(SSL *s, struct hm_header_st *msg_hdr,
524 size_t frag_off, frag_len, msg_len;
526 msg_len = msg_hdr->msg_len;
527 frag_off = msg_hdr->frag_off;
528 frag_len = msg_hdr->frag_len;
530 /* sanity checking */
531 if ((frag_off + frag_len) > msg_len) {
532 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT, SSL_R_EXCESSIVE_MESSAGE_SIZE);
533 return SSL_AD_ILLEGAL_PARAMETER;
536 if ((frag_off + frag_len) > (unsigned long)max) {
537 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT, SSL_R_EXCESSIVE_MESSAGE_SIZE);
538 return SSL_AD_ILLEGAL_PARAMETER;
541 if (s->d1->r_msg_hdr.frag_off == 0) { /* first fragment */
543 * msg_len is limited to 2^24, but is effectively checked against max
546 if (!BUF_MEM_grow_clean
547 (s->init_buf, msg_len + DTLS1_HM_HEADER_LENGTH)) {
548 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT, ERR_R_BUF_LIB);
549 return SSL_AD_INTERNAL_ERROR;
552 s->s3->tmp.message_size = msg_len;
553 s->d1->r_msg_hdr.msg_len = msg_len;
554 s->s3->tmp.message_type = msg_hdr->type;
555 s->d1->r_msg_hdr.type = msg_hdr->type;
556 s->d1->r_msg_hdr.seq = msg_hdr->seq;
557 } else if (msg_len != s->d1->r_msg_hdr.msg_len) {
559 * They must be playing with us! BTW, failure to enforce upper limit
560 * would open possibility for buffer overrun.
562 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT, SSL_R_EXCESSIVE_MESSAGE_SIZE);
563 return SSL_AD_ILLEGAL_PARAMETER;
566 return 0; /* no error */
569 static int dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok)
572 * (0) check whether the desired fragment is available
574 * (1) copy over the fragment to s->init_buf->data[]
575 * (2) update s->init_num
582 item = pqueue_peek(s->d1->buffered_messages);
586 frag = (hm_fragment *)item->data;
588 /* Don't return if reassembly still in progress */
589 if (frag->reassembly != NULL)
592 if (s->d1->handshake_read_seq == frag->msg_header.seq) {
593 unsigned long frag_len = frag->msg_header.frag_len;
594 pqueue_pop(s->d1->buffered_messages);
596 al = dtls1_preprocess_fragment(s, &frag->msg_header, max);
598 if (al == 0) { /* no alert */
600 (unsigned char *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
601 memcpy(&p[frag->msg_header.frag_off], frag->fragment,
602 frag->msg_header.frag_len);
605 dtls1_hm_fragment_free(frag);
613 ssl3_send_alert(s, SSL3_AL_FATAL, al);
622 * dtls1_max_handshake_message_len returns the maximum number of bytes
623 * permitted in a DTLS handshake message for |s|. The minimum is 16KB, but
624 * may be greater if the maximum certificate list size requires it.
626 static unsigned long dtls1_max_handshake_message_len(const SSL *s)
628 unsigned long max_len =
629 DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
630 if (max_len < (unsigned long)s->max_cert_list)
631 return s->max_cert_list;
636 dtls1_reassemble_fragment(SSL *s, const struct hm_header_st *msg_hdr, int *ok)
638 hm_fragment *frag = NULL;
640 int i = -1, is_complete;
641 unsigned char seq64be[8];
642 unsigned long frag_len = msg_hdr->frag_len;
644 if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len ||
645 msg_hdr->msg_len > dtls1_max_handshake_message_len(s))
649 return DTLS1_HM_FRAGMENT_RETRY;
651 /* Try to find item in queue */
652 memset(seq64be, 0, sizeof(seq64be));
653 seq64be[6] = (unsigned char)(msg_hdr->seq >> 8);
654 seq64be[7] = (unsigned char)msg_hdr->seq;
655 item = pqueue_find(s->d1->buffered_messages, seq64be);
658 frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1);
661 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
662 frag->msg_header.frag_len = frag->msg_header.msg_len;
663 frag->msg_header.frag_off = 0;
665 frag = (hm_fragment *)item->data;
666 if (frag->msg_header.msg_len != msg_hdr->msg_len) {
674 * If message is already reassembled, this must be a retransmit and can
675 * be dropped. In this case item != NULL and so frag does not need to be
678 if (frag->reassembly == NULL) {
679 unsigned char devnull[256];
682 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
685 sizeof(devnull) ? sizeof(devnull) :
691 return DTLS1_HM_FRAGMENT_RETRY;
694 /* read the body of the fragment (header has already been read */
695 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
696 frag->fragment + msg_hdr->frag_off,
698 if ((unsigned long)i != frag_len)
703 RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off,
704 (long)(msg_hdr->frag_off + frag_len));
706 RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len,
710 OPENSSL_free(frag->reassembly);
711 frag->reassembly = NULL;
715 item = pitem_new(seq64be, frag);
721 item = pqueue_insert(s->d1->buffered_messages, item);
723 * pqueue_insert fails iff a duplicate item is inserted. However,
724 * |item| cannot be a duplicate. If it were, |pqueue_find|, above,
725 * would have returned it and control would never have reached this
728 OPENSSL_assert(item != NULL);
731 return DTLS1_HM_FRAGMENT_RETRY;
735 dtls1_hm_fragment_free(frag);
741 dtls1_process_out_of_seq_message(SSL *s, const struct hm_header_st *msg_hdr,
745 hm_fragment *frag = NULL;
747 unsigned char seq64be[8];
748 unsigned long frag_len = msg_hdr->frag_len;
750 if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len)
753 /* Try to find item in queue, to prevent duplicate entries */
754 memset(seq64be, 0, sizeof(seq64be));
755 seq64be[6] = (unsigned char)(msg_hdr->seq >> 8);
756 seq64be[7] = (unsigned char)msg_hdr->seq;
757 item = pqueue_find(s->d1->buffered_messages, seq64be);
760 * If we already have an entry and this one is a fragment, don't discard
761 * it and rather try to reassemble it.
763 if (item != NULL && frag_len != msg_hdr->msg_len)
767 * Discard the message if sequence number was already there, is too far
768 * in the future, already in the queue or if we received a FINISHED
769 * before the SERVER_HELLO, which then must be a stale retransmit.
771 if (msg_hdr->seq <= s->d1->handshake_read_seq ||
772 msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL ||
773 (s->d1->handshake_read_seq == 0 && msg_hdr->type == SSL3_MT_FINISHED))
775 unsigned char devnull[256];
778 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
781 sizeof(devnull) ? sizeof(devnull) :
788 if (frag_len != msg_hdr->msg_len)
789 return dtls1_reassemble_fragment(s, msg_hdr, ok);
791 if (frag_len > dtls1_max_handshake_message_len(s))
794 frag = dtls1_hm_fragment_new(frag_len, 0);
798 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
802 * read the body of the fragment (header has already been read
804 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
805 frag->fragment, frag_len, 0);
806 if ((unsigned long)i != frag_len)
812 item = pitem_new(seq64be, frag);
816 item = pqueue_insert(s->d1->buffered_messages, item);
818 * pqueue_insert fails iff a duplicate item is inserted. However,
819 * |item| cannot be a duplicate. If it were, |pqueue_find|, above,
820 * would have returned it. Then, either |frag_len| !=
821 * |msg_hdr->msg_len| in which case |item| is set to NULL and it will
822 * have been processed with |dtls1_reassemble_fragment|, above, or
823 * the record will have been discarded.
825 OPENSSL_assert(item != NULL);
828 return DTLS1_HM_FRAGMENT_RETRY;
832 dtls1_hm_fragment_free(frag);
838 dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
840 unsigned char wire[DTLS1_HM_HEADER_LENGTH];
841 unsigned long len, frag_off, frag_len;
843 struct hm_header_st msg_hdr;
846 /* see if we have the required fragment already */
847 if ((frag_len = dtls1_retrieve_buffered_fragment(s, max, ok)) || *ok) {
849 s->init_num = frag_len;
853 /* read handshake message header */
854 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, wire,
855 DTLS1_HM_HEADER_LENGTH, 0);
856 if (i <= 0) { /* nbio, or an error */
857 s->rwstate = SSL_READING;
861 /* Handshake fails if message header is incomplete */
862 if (i != DTLS1_HM_HEADER_LENGTH) {
863 al = SSL_AD_UNEXPECTED_MESSAGE;
864 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT, SSL_R_UNEXPECTED_MESSAGE);
868 /* parse the message fragment header */
869 dtls1_get_message_header(wire, &msg_hdr);
871 len = msg_hdr.msg_len;
872 frag_off = msg_hdr.frag_off;
873 frag_len = msg_hdr.frag_len;
876 * We must have at least frag_len bytes left in the record to be read.
877 * Fragments must not span records.
879 if (frag_len > RECORD_LAYER_get_rrec_length(&s->rlayer)) {
880 al = SSL3_AD_ILLEGAL_PARAMETER;
881 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT, SSL_R_BAD_LENGTH);
886 * if this is a future (or stale) message it gets buffered
887 * (or dropped)--no further processing at this time
888 * While listening, we accept seq 1 (ClientHello with cookie)
889 * although we're still expecting seq 0 (ClientHello)
891 if (msg_hdr.seq != s->d1->handshake_read_seq
892 && !(s->d1->listen && msg_hdr.seq == 1))
893 return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
895 if (frag_len && frag_len < len)
896 return dtls1_reassemble_fragment(s, &msg_hdr, ok);
898 if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
899 wire[0] == SSL3_MT_HELLO_REQUEST) {
901 * The server may always send 'Hello Request' messages -- we are
902 * doing a handshake anyway now, so ignore them if their format is
903 * correct. Does not count for 'Finished' MAC.
905 if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0) {
907 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
908 wire, DTLS1_HM_HEADER_LENGTH, s,
909 s->msg_callback_arg);
913 } else { /* Incorrectly formated Hello request */
915 al = SSL_AD_UNEXPECTED_MESSAGE;
916 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,
917 SSL_R_UNEXPECTED_MESSAGE);
922 if ((al = dtls1_preprocess_fragment(s, &msg_hdr, max)))
927 (unsigned char *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
929 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
930 &p[frag_off], frag_len, 0);
933 * This shouldn't ever fail due to NBIO because we already checked
934 * that we have enough data in the record
937 s->rwstate = SSL_READING;
945 * XDTLS: an incorrectly formatted fragment should cause the handshake
948 if (i != (int)frag_len) {
949 al = SSL3_AD_ILLEGAL_PARAMETER;
950 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT, SSL3_AD_ILLEGAL_PARAMETER);
958 * Note that s->init_num is *not* used as current offset in
959 * s->init_buf->data, but as a counter summing up fragments' lengths: as
960 * soon as they sum up to handshake packet length, we assume we have got
963 s->init_num = frag_len;
967 ssl3_send_alert(s, SSL3_AL_FATAL, al);
975 * for these 2 messages, we need to
976 * ssl->enc_read_ctx re-init
977 * ssl->rlayer.read_sequence zero
978 * ssl->s3->read_mac_secret re-init
979 * ssl->session->read_sym_enc assign
980 * ssl->session->read_compression assign
981 * ssl->session->read_hash assign
983 int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
988 p = (unsigned char *)s->init_buf->data;
990 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
991 s->init_num = DTLS1_CCS_HEADER_LENGTH;
993 if (s->version == DTLS1_BAD_VER) {
994 s->d1->next_handshake_write_seq++;
995 s2n(s->d1->handshake_write_seq, p);
1001 dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
1002 s->d1->handshake_write_seq, 0, 0);
1004 /* buffer the message to handle re-xmits */
1005 if (!dtls1_buffer_message(s, 1)) {
1006 SSLerr(SSL_F_DTLS1_SEND_CHANGE_CIPHER_SPEC, ERR_R_INTERNAL_ERROR);
1013 /* SSL3_ST_CW_CHANGE_B */
1014 return (dtls1_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC));
1017 int dtls1_read_failed(SSL *s, int code)
1020 fprintf(stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
1024 if (!dtls1_is_timer_expired(s)) {
1026 * not a timeout, none of our business, let higher layers handle
1027 * this. in fact it's probably an error
1031 #ifndef OPENSSL_NO_HEARTBEATS
1032 /* done, no need to send a retransmit */
1033 if (!SSL_in_init(s) && !s->tlsext_hb_pending)
1035 /* done, no need to send a retransmit */
1036 if (!SSL_in_init(s))
1039 BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
1043 return dtls1_handle_timeout(s);
1046 int dtls1_get_queue_priority(unsigned short seq, int is_ccs)
1049 * The index of the retransmission queue actually is the message sequence
1050 * number, since the queue only contains messages of a single handshake.
1051 * However, the ChangeCipherSpec has no message sequence number and so
1052 * using only the sequence will result in the CCS and Finished having the
1053 * same index. To prevent this, the sequence number is multiplied by 2.
1054 * In case of a CCS 1 is subtracted. This does not only differ CSS and
1055 * Finished, it also maintains the order of the index (important for
1056 * priority queues) and fits in the unsigned short variable.
1058 return seq * 2 - is_ccs;
1061 int dtls1_retransmit_buffered_messages(SSL *s)
1063 pqueue sent = s->d1->sent_messages;
1069 iter = pqueue_iterator(sent);
1071 for (item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter)) {
1072 frag = (hm_fragment *)item->data;
1073 if (dtls1_retransmit_message(s, (unsigned short)
1074 dtls1_get_queue_priority
1075 (frag->msg_header.seq,
1076 frag->msg_header.is_ccs), 0,
1077 &found) <= 0 && found) {
1078 fprintf(stderr, "dtls1_retransmit_message() failed\n");
1086 int dtls1_buffer_message(SSL *s, int is_ccs)
1090 unsigned char seq64be[8];
1093 * this function is called immediately after a message has been
1096 OPENSSL_assert(s->init_off == 0);
1098 frag = dtls1_hm_fragment_new(s->init_num, 0);
1102 memcpy(frag->fragment, s->init_buf->data, s->init_num);
1105 /* For DTLS1_BAD_VER the header length is non-standard */
1106 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1107 ((s->version==DTLS1_BAD_VER)?3:DTLS1_CCS_HEADER_LENGTH)
1108 == (unsigned int)s->init_num);
1110 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1111 DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num);
1114 frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
1115 frag->msg_header.seq = s->d1->w_msg_hdr.seq;
1116 frag->msg_header.type = s->d1->w_msg_hdr.type;
1117 frag->msg_header.frag_off = 0;
1118 frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
1119 frag->msg_header.is_ccs = is_ccs;
1121 /* save current state */
1122 frag->msg_header.saved_retransmit_state.enc_write_ctx = s->enc_write_ctx;
1123 frag->msg_header.saved_retransmit_state.write_hash = s->write_hash;
1124 frag->msg_header.saved_retransmit_state.compress = s->compress;
1125 frag->msg_header.saved_retransmit_state.session = s->session;
1126 frag->msg_header.saved_retransmit_state.epoch =
1127 DTLS_RECORD_LAYER_get_w_epoch(&s->rlayer);
1129 memset(seq64be, 0, sizeof(seq64be));
1132 char)(dtls1_get_queue_priority(frag->msg_header.seq,
1133 frag->msg_header.is_ccs) >> 8);
1136 char)(dtls1_get_queue_priority(frag->msg_header.seq,
1137 frag->msg_header.is_ccs));
1139 item = pitem_new(seq64be, frag);
1141 dtls1_hm_fragment_free(frag);
1145 pqueue_insert(s->d1->sent_messages, item);
1150 dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
1154 /* XDTLS: for now assuming that read/writes are blocking */
1157 unsigned long header_length;
1158 unsigned char seq64be[8];
1159 struct dtls1_retransmit_state saved_state;
1162 OPENSSL_assert(s->init_num == 0);
1163 OPENSSL_assert(s->init_off == 0);
1166 /* XDTLS: the requested message ought to be found, otherwise error */
1167 memset(seq64be, 0, sizeof(seq64be));
1168 seq64be[6] = (unsigned char)(seq >> 8);
1169 seq64be[7] = (unsigned char)seq;
1171 item = pqueue_find(s->d1->sent_messages, seq64be);
1173 fprintf(stderr, "retransmit: message %d non-existant\n", seq);
1179 frag = (hm_fragment *)item->data;
1181 if (frag->msg_header.is_ccs)
1182 header_length = DTLS1_CCS_HEADER_LENGTH;
1184 header_length = DTLS1_HM_HEADER_LENGTH;
1186 memcpy(s->init_buf->data, frag->fragment,
1187 frag->msg_header.msg_len + header_length);
1188 s->init_num = frag->msg_header.msg_len + header_length;
1190 dtls1_set_message_header_int(s, frag->msg_header.type,
1191 frag->msg_header.msg_len,
1192 frag->msg_header.seq, 0,
1193 frag->msg_header.frag_len);
1195 /* save current state */
1196 saved_state.enc_write_ctx = s->enc_write_ctx;
1197 saved_state.write_hash = s->write_hash;
1198 saved_state.compress = s->compress;
1199 saved_state.session = s->session;
1200 saved_state.epoch = DTLS_RECORD_LAYER_get_w_epoch(&s->rlayer);
1202 s->d1->retransmitting = 1;
1204 /* restore state in which the message was originally sent */
1205 s->enc_write_ctx = frag->msg_header.saved_retransmit_state.enc_write_ctx;
1206 s->write_hash = frag->msg_header.saved_retransmit_state.write_hash;
1207 s->compress = frag->msg_header.saved_retransmit_state.compress;
1208 s->session = frag->msg_header.saved_retransmit_state.session;
1209 DTLS_RECORD_LAYER_set_saved_w_epoch(&s->rlayer,
1210 frag->msg_header.saved_retransmit_state.epoch);
1212 ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1213 SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1215 /* restore current state */
1216 s->enc_write_ctx = saved_state.enc_write_ctx;
1217 s->write_hash = saved_state.write_hash;
1218 s->compress = saved_state.compress;
1219 s->session = saved_state.session;
1220 DTLS_RECORD_LAYER_set_saved_w_epoch(&s->rlayer, saved_state.epoch);
1222 s->d1->retransmitting = 0;
1224 (void)BIO_flush(SSL_get_wbio(s));
1228 /* call this function when the buffered messages are no longer needed */
1229 void dtls1_clear_record_buffer(SSL *s)
1233 for (item = pqueue_pop(s->d1->sent_messages);
1234 item != NULL; item = pqueue_pop(s->d1->sent_messages)) {
1235 dtls1_hm_fragment_free((hm_fragment *)item->data);
1240 void dtls1_set_message_header(SSL *s, unsigned char *p,
1241 unsigned char mt, unsigned long len,
1242 unsigned long frag_off,
1243 unsigned long frag_len)
1245 /* Don't change sequence numbers while listening */
1246 if (frag_off == 0 && !s->d1->listen) {
1247 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1248 s->d1->next_handshake_write_seq++;
1251 dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1252 frag_off, frag_len);
1255 /* don't actually do the writing, wait till the MTU has been retrieved */
1257 dtls1_set_message_header_int(SSL *s, unsigned char mt,
1258 unsigned long len, unsigned short seq_num,
1259 unsigned long frag_off, unsigned long frag_len)
1261 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1264 msg_hdr->msg_len = len;
1265 msg_hdr->seq = seq_num;
1266 msg_hdr->frag_off = frag_off;
1267 msg_hdr->frag_len = frag_len;
1271 dtls1_fix_message_header(SSL *s, unsigned long frag_off,
1272 unsigned long frag_len)
1274 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1276 msg_hdr->frag_off = frag_off;
1277 msg_hdr->frag_len = frag_len;
1280 static unsigned char *dtls1_write_message_header(SSL *s, unsigned char *p)
1282 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1284 *p++ = msg_hdr->type;
1285 l2n3(msg_hdr->msg_len, p);
1287 s2n(msg_hdr->seq, p);
1288 l2n3(msg_hdr->frag_off, p);
1289 l2n3(msg_hdr->frag_len, p);
1294 unsigned int dtls1_link_min_mtu(void)
1296 return (g_probable_mtu[(sizeof(g_probable_mtu) /
1297 sizeof(g_probable_mtu[0])) - 1]);
1300 unsigned int dtls1_min_mtu(SSL *s)
1302 return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
1306 dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
1308 memset(msg_hdr, 0, sizeof(*msg_hdr));
1309 msg_hdr->type = *(data++);
1310 n2l3(data, msg_hdr->msg_len);
1312 n2s(data, msg_hdr->seq);
1313 n2l3(data, msg_hdr->frag_off);
1314 n2l3(data, msg_hdr->frag_len);
1317 int dtls1_shutdown(SSL *s)
1320 #ifndef OPENSSL_NO_SCTP
1321 if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
1322 !(s->shutdown & SSL_SENT_SHUTDOWN)) {
1323 ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
1328 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1,
1332 ret = ssl3_shutdown(s);
1333 #ifndef OPENSSL_NO_SCTP
1334 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
1339 #ifndef OPENSSL_NO_HEARTBEATS
1340 int dtls1_process_heartbeat(SSL *s, unsigned char *p, unsigned int length)
1343 unsigned short hbtype;
1344 unsigned int payload;
1345 unsigned int padding = 16; /* Use minimum padding */
1347 if (s->msg_callback)
1348 s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
1349 p, length, s, s->msg_callback_arg);
1351 /* Read type and payload length first */
1352 if (1 + 2 + 16 > length)
1353 return 0; /* silently discard */
1354 if (length > SSL3_RT_MAX_PLAIN_LENGTH)
1355 return 0; /* silently discard per RFC 6520 sec. 4 */
1359 if (1 + 2 + payload + 16 > length)
1360 return 0; /* silently discard per RFC 6520 sec. 4 */
1363 if (hbtype == TLS1_HB_REQUEST) {
1364 unsigned char *buffer, *bp;
1365 unsigned int write_length = 1 /* heartbeat type */ +
1366 2 /* heartbeat length */ +
1370 if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
1374 * Allocate memory for the response, size is 1 byte message type,
1375 * plus 2 bytes payload length, plus payload, plus padding
1377 buffer = OPENSSL_malloc(write_length);
1382 /* Enter response type, length and copy payload */
1383 *bp++ = TLS1_HB_RESPONSE;
1385 memcpy(bp, pl, payload);
1387 /* Random padding */
1388 if (RAND_bytes(bp, padding) <= 0) {
1389 OPENSSL_free(buffer);
1393 r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, write_length);
1395 if (r >= 0 && s->msg_callback)
1396 s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1397 buffer, write_length, s, s->msg_callback_arg);
1399 OPENSSL_free(buffer);
1403 } else if (hbtype == TLS1_HB_RESPONSE) {
1407 * We only send sequence numbers (2 bytes unsigned int), and 16
1408 * random bytes, so we just try to read the sequence number
1412 if (payload == 18 && seq == s->tlsext_hb_seq) {
1413 dtls1_stop_timer(s);
1415 s->tlsext_hb_pending = 0;
1422 int dtls1_heartbeat(SSL *s)
1424 unsigned char *buf, *p;
1426 unsigned int payload = 18; /* Sequence number + random bytes */
1427 unsigned int padding = 16; /* Use minimum padding */
1429 /* Only send if peer supports and accepts HB requests... */
1430 if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
1431 s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS) {
1432 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
1436 /* ...and there is none in flight yet... */
1437 if (s->tlsext_hb_pending) {
1438 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PENDING);
1442 /* ...and no handshake in progress. */
1443 if (SSL_in_init(s) || s->in_handshake) {
1444 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_UNEXPECTED_MESSAGE);
1449 * Check if padding is too long, payload and padding must not exceed 2^14
1450 * - 3 = 16381 bytes in total.
1452 OPENSSL_assert(payload + padding <= 16381);
1455 * Create HeartBeat message, we just use a sequence number
1456 * as payload to distuingish different messages and add
1457 * some random stuff.
1458 * - Message Type, 1 byte
1459 * - Payload Length, 2 bytes (unsigned int)
1460 * - Payload, the sequence number (2 bytes uint)
1461 * - Payload, random bytes (16 bytes uint)
1464 buf = OPENSSL_malloc(1 + 2 + payload + padding);
1466 SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_MALLOC_FAILURE);
1471 *p++ = TLS1_HB_REQUEST;
1472 /* Payload length (18 bytes here) */
1474 /* Sequence number */
1475 s2n(s->tlsext_hb_seq, p);
1476 /* 16 random bytes */
1477 if (RAND_bytes(p, 16) <= 0) {
1478 SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_INTERNAL_ERROR);
1482 /* Random padding */
1483 if (RAND_bytes(p, padding) <= 0) {
1484 SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_INTERNAL_ERROR);
1488 ret = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buf, 3 + payload + padding);
1490 if (s->msg_callback)
1491 s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1492 buf, 3 + payload + padding,
1493 s, s->msg_callback_arg);
1495 dtls1_start_timer(s);
1496 s->tlsext_hb_pending = 1;