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[] = {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80};
156 static unsigned char bitmask_end_values[] = {0xff, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f};
158 /* XDTLS: figure out the right values */
159 static const unsigned int g_probable_mtu[] = {1500, 512, 256};
161 static void dtls1_fix_message_header(SSL *s, unsigned long frag_off,
162 unsigned long frag_len);
163 static unsigned char *dtls1_write_message_header(SSL *s,
165 static void dtls1_set_message_header_int(SSL *s, unsigned char mt,
166 unsigned long len, unsigned short seq_num, unsigned long frag_off,
167 unsigned long frag_len);
168 static long dtls1_get_message_fragment(SSL *s, int st1, int stn,
172 dtls1_hm_fragment_new(unsigned long frag_len, int reassembly)
174 hm_fragment *frag = NULL;
175 unsigned char *buf = NULL;
176 unsigned char *bitmask = NULL;
178 frag = (hm_fragment *)OPENSSL_malloc(sizeof(hm_fragment));
184 buf = (unsigned char *)OPENSSL_malloc(frag_len);
192 /* zero length fragment gets zero frag->fragment */
193 frag->fragment = buf;
195 /* Initialize reassembly bitmask if necessary */
198 bitmask = (unsigned char *)OPENSSL_malloc(RSMBLY_BITMASK_SIZE(frag_len));
201 if (buf != NULL) OPENSSL_free(buf);
205 memset(bitmask, 0, RSMBLY_BITMASK_SIZE(frag_len));
208 frag->reassembly = bitmask;
213 void dtls1_hm_fragment_free(hm_fragment *frag)
216 if (frag->msg_header.is_ccs)
218 EVP_CIPHER_CTX_free(frag->msg_header.saved_retransmit_state.enc_write_ctx);
219 EVP_MD_CTX_destroy(frag->msg_header.saved_retransmit_state.write_hash);
221 if (frag->fragment) OPENSSL_free(frag->fragment);
222 if (frag->reassembly) OPENSSL_free(frag->reassembly);
226 static int dtls1_query_mtu(SSL *s)
230 s->d1->mtu = s->d1->link_mtu-BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
234 /* AHA! Figure out the MTU, and stick to the right size */
235 if (s->d1->mtu < dtls1_min_mtu(s))
237 if(!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))
240 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
242 /* I've seen the kernel return bogus numbers when it doesn't know
243 * (initial write), so just make sure we have a reasonable number */
244 if (s->d1->mtu < dtls1_min_mtu(s))
247 s->d1->mtu = dtls1_min_mtu(s);
248 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
258 /* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */
259 int dtls1_do_write(SSL *s, int type)
262 unsigned int curr_mtu;
264 unsigned int len, frag_off, mac_size, blocksize, used_len;
266 if(!dtls1_query_mtu(s))
269 OPENSSL_assert(s->d1->mtu >= dtls1_min_mtu(s)); /* should have something reasonable now */
271 if ( s->init_off == 0 && type == SSL3_RT_HANDSHAKE)
272 OPENSSL_assert(s->init_num ==
273 (int)s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH);
276 mac_size = EVP_MD_CTX_size(s->write_hash);
280 if (s->enc_write_ctx &&
281 (EVP_CIPHER_mode( s->enc_write_ctx->cipher) & 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)
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 */
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)
306 curr_mtu = s->d1->mtu - used_len;
310 /* Shouldn't happen */
315 /* 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 */
325 /* XDTLS: this function is too long. split out the CCS part */
326 if ( type == SSL3_RT_HANDSHAKE)
328 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;
334 /* We just checked that s->init_num > 0 so this cast should be safe */
335 if (((unsigned int)s->init_num) > curr_mtu)
341 /* Shouldn't ever happen */
345 if ( len < DTLS1_HM_HEADER_LENGTH )
348 * len is so small that we really can't do anything sensible
353 dtls1_fix_message_header(s, frag_off,
354 len - DTLS1_HM_HEADER_LENGTH);
356 dtls1_write_message_header(s, (unsigned char *)&s->init_buf->data[s->init_off]);
359 ret=dtls1_write_bytes(s,type,&s->init_buf->data[s->init_off],
363 /* might need to update MTU here, but we don't know
364 * which previous packet caused the failure -- so can't
365 * really retransmit anything. continue as if everything
366 * is fine and wait for an alert to handle the
369 if ( retry && BIO_ctrl(SSL_get_wbio(s),
370 BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0 )
372 if(!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))
374 if(!dtls1_query_mtu(s))
376 /* Have one more go */
390 /* bad if this assert fails, only part of the handshake
391 * message got sent. but why would this happen? */
392 OPENSSL_assert(len == (unsigned int)ret);
394 if (type == SSL3_RT_HANDSHAKE && ! s->d1->retransmitting)
396 /* should not be done for 'Hello Request's, but in that case
397 * we'll ignore the result anyway */
398 unsigned char *p = (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
405 * is being sent in single fragment */
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;
416 p += DTLS1_HM_HEADER_LENGTH;
417 xlen = ret - DTLS1_HM_HEADER_LENGTH;
420 ssl3_finish_mac(s, p, xlen);
423 if (ret == s->init_num)
426 s->msg_callback(1, s->version, type, s->init_buf->data,
427 (size_t)(s->init_off + s->init_num), s,
428 s->msg_callback_arg);
430 s->init_off = 0; /* done writing this message */
437 frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
444 /* Obtain handshake message of message type 'mt' (any if mt == -1),
445 * maximum acceptable body length 'max'.
446 * Read an entire handshake message. Handshake messages arrive in
449 long dtls1_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
452 struct hm_header_st *msg_hdr;
454 unsigned long msg_len;
456 /* s3->tmp is used to store messages that are unexpected, caused
457 * by the absence of an optional handshake message */
458 if (s->s3->tmp.reuse_message)
460 s->s3->tmp.reuse_message=0;
461 if ((mt >= 0) && (s->s3->tmp.message_type != mt))
463 al=SSL_AD_UNEXPECTED_MESSAGE;
464 SSLerr(SSL_F_DTLS1_GET_MESSAGE,SSL_R_UNEXPECTED_MESSAGE);
468 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
469 s->init_num = (int)s->s3->tmp.message_size;
473 msg_hdr = &s->d1->r_msg_hdr;
474 memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
477 i = dtls1_get_message_fragment(s, st1, stn, max, ok);
478 if ( i == DTLS1_HM_BAD_FRAGMENT ||
479 i == DTLS1_HM_FRAGMENT_RETRY) /* bad fragment received */
481 else if ( i <= 0 && !*ok)
484 p = (unsigned char *)s->init_buf->data;
485 msg_len = msg_hdr->msg_len;
487 /* reconstruct message header */
488 *(p++) = msg_hdr->type;
490 s2n (msg_hdr->seq,p);
493 if (s->version != DTLS1_BAD_VER) {
494 p -= DTLS1_HM_HEADER_LENGTH;
495 msg_len += DTLS1_HM_HEADER_LENGTH;
498 ssl3_finish_mac(s, p, msg_len);
500 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
502 s, s->msg_callback_arg);
504 memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
506 /* Don't change sequence numbers while listening */
508 s->d1->handshake_read_seq++;
510 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
514 ssl3_send_alert(s,SSL3_AL_FATAL,al);
520 static int dtls1_preprocess_fragment(SSL *s,struct hm_header_st *msg_hdr,int max)
522 size_t frag_off,frag_len,msg_len;
524 msg_len = msg_hdr->msg_len;
525 frag_off = msg_hdr->frag_off;
526 frag_len = msg_hdr->frag_len;
528 /* sanity checking */
529 if ( (frag_off+frag_len) > msg_len)
531 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
532 return SSL_AD_ILLEGAL_PARAMETER;
535 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
544 * against max above */
545 if (!BUF_MEM_grow_clean(s->init_buf,msg_len+DTLS1_HM_HEADER_LENGTH))
547 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,ERR_R_BUF_LIB);
548 return SSL_AD_INTERNAL_ERROR;
551 s->s3->tmp.message_size = msg_len;
552 s->d1->r_msg_hdr.msg_len = msg_len;
553 s->s3->tmp.message_type = msg_hdr->type;
554 s->d1->r_msg_hdr.type = msg_hdr->type;
555 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
560 * upper limit would open possibility for buffer overrun. */
561 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
562 return SSL_AD_ILLEGAL_PARAMETER;
565 return 0; /* no error */
570 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)
594 unsigned long frag_len = frag->msg_header.frag_len;
595 pqueue_pop(s->d1->buffered_messages);
597 al=dtls1_preprocess_fragment(s,&frag->msg_header,max);
599 if (al==0) /* no alert */
601 unsigned char *p = (unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
602 memcpy(&p[frag->msg_header.frag_off],
603 frag->fragment,frag->msg_header.frag_len);
606 dtls1_hm_fragment_free(frag);
615 ssl3_send_alert(s,SSL3_AL_FATAL,al);
624 /* dtls1_max_handshake_message_len returns the maximum number of bytes
625 * permitted in a DTLS handshake message for |s|. The minimum is 16KB, but may
626 * be greater if the maximum certificate list size requires it. */
627 static unsigned long dtls1_max_handshake_message_len(const SSL *s)
629 unsigned long max_len = 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);
659 frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1);
662 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
663 frag->msg_header.frag_len = frag->msg_header.msg_len;
664 frag->msg_header.frag_off = 0;
668 frag = (hm_fragment*) item->data;
669 if (frag->msg_header.msg_len != msg_hdr->msg_len)
678 /* If message is already reassembled, this must be a
679 * retransmit and can be dropped. In this case item != NULL and so frag
680 * does not need to be freed.
682 if (frag->reassembly == NULL)
684 unsigned char devnull [256];
688 i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
690 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
694 return DTLS1_HM_FRAGMENT_RETRY;
697 /* read the body of the fragment (header has already been read */
698 i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
699 frag->fragment + msg_hdr->frag_off,frag_len,0);
700 if ((unsigned long)i!=frag_len)
705 RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off,
706 (long)(msg_hdr->frag_off + frag_len));
708 RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len,
713 OPENSSL_free(frag->reassembly);
714 frag->reassembly = NULL;
719 item = pitem_new(seq64be, frag);
726 item = pqueue_insert(s->d1->buffered_messages, item);
727 /* pqueue_insert fails iff a duplicate item is inserted.
728 * However, |item| cannot be a duplicate. If it were,
729 * |pqueue_find|, above, would have returned it and control
730 * would never have reached this branch. */
731 OPENSSL_assert(item != NULL);
734 return DTLS1_HM_FRAGMENT_RETRY;
737 if (frag != NULL && item == NULL) dtls1_hm_fragment_free(frag);
744 dtls1_process_out_of_seq_message(SSL *s, const struct hm_header_st* msg_hdr, int *ok)
747 hm_fragment *frag = NULL;
749 unsigned char seq64be[8];
750 unsigned long frag_len = msg_hdr->frag_len;
752 if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len)
755 /* Try to find item in queue, to prevent duplicate entries */
756 memset(seq64be,0,sizeof(seq64be));
757 seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
758 seq64be[7] = (unsigned char) msg_hdr->seq;
759 item = pqueue_find(s->d1->buffered_messages, seq64be);
761 /* If we already have an entry and this one is a fragment,
762 * don't discard it and rather try to reassemble it.
764 if (item != NULL && frag_len != msg_hdr->msg_len)
767 /* Discard the message if sequence number was already there, is
768 * too far in the future, already in the queue or if we received
769 * a FINISHED before the SERVER_HELLO, which then must be a stale
772 if (msg_hdr->seq <= s->d1->handshake_read_seq ||
773 msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL ||
774 (s->d1->handshake_read_seq == 0 && msg_hdr->type == SSL3_MT_FINISHED))
776 unsigned char devnull [256];
780 i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
782 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
789 if (frag_len != msg_hdr->msg_len)
790 return dtls1_reassemble_fragment(s, msg_hdr, ok);
792 if (frag_len > dtls1_max_handshake_message_len(s))
795 frag = dtls1_hm_fragment_new(frag_len, 0);
799 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
803 /* 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);
817 /* pqueue_insert fails iff a duplicate item is inserted.
818 * However, |item| cannot be a duplicate. If it were,
819 * |pqueue_find|, above, would have returned it. Then, either
820 * |frag_len| != |msg_hdr->msg_len| in which case |item| is set
821 * to NULL and it will have been processed with
822 * |dtls1_reassemble_fragment|, above, or the record will have
824 OPENSSL_assert(item != NULL);
827 return DTLS1_HM_FRAGMENT_RETRY;
830 if (frag != NULL && item == NULL) dtls1_hm_fragment_free(frag);
837 dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
839 unsigned char wire[DTLS1_HM_HEADER_LENGTH];
840 unsigned long len, frag_off, frag_len;
842 struct hm_header_st msg_hdr;
845 /* see if we have the required fragment already */
846 if ((frag_len = dtls1_retrieve_buffered_fragment(s,max,ok)) || *ok)
848 if (*ok) s->init_num = frag_len;
852 /* read handshake message header */
853 i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,wire,
854 DTLS1_HM_HEADER_LENGTH, 0);
855 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)
864 al=SSL_AD_UNEXPECTED_MESSAGE;
865 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
869 /* parse the message fragment header */
870 dtls1_get_message_header(wire, &msg_hdr);
873 * if this is a future (or stale) message it gets buffered
874 * (or dropped)--no further processing at this time
875 * While listening, we accept seq 1 (ClientHello with cookie)
876 * although we're still expecting seq 0 (ClientHello)
878 if (msg_hdr.seq != s->d1->handshake_read_seq && !(s->d1->listen && msg_hdr.seq == 1))
879 return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
881 len = msg_hdr.msg_len;
882 frag_off = msg_hdr.frag_off;
883 frag_len = msg_hdr.frag_len;
885 if (frag_len && frag_len < len)
886 return dtls1_reassemble_fragment(s, &msg_hdr, ok);
888 if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
889 wire[0] == SSL3_MT_HELLO_REQUEST)
891 /* The server may always send 'Hello Request' messages --
892 * we are doing a handshake anyway now, so ignore them
893 * if their format is correct. Does not count for
895 if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0)
898 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
899 wire, DTLS1_HM_HEADER_LENGTH, s,
900 s->msg_callback_arg);
905 else /* Incorrectly formated Hello request */
907 al=SSL_AD_UNEXPECTED_MESSAGE;
908 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
913 if ((al=dtls1_preprocess_fragment(s,&msg_hdr,max)))
916 /* XDTLS: ressurect this when restart is in place */
921 unsigned char *p=(unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
923 i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
924 &p[frag_off],frag_len,0);
925 /* XDTLS: fix this--message fragments cannot span multiple packets */
928 s->rwstate=SSL_READING;
936 /* XDTLS: an incorrectly formatted fragment should cause the
937 * handshake to fail */
938 if (i != (int)frag_len)
940 al=SSL3_AD_ILLEGAL_PARAMETER;
941 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL3_AD_ILLEGAL_PARAMETER);
947 /* Note that s->init_num is *not* used as current offset in
948 * s->init_buf->data, but as a counter summing up fragments'
949 * lengths: as soon as they sum up to handshake packet
950 * length, we assume we have got all the fragments. */
951 s->init_num = frag_len;
955 ssl3_send_alert(s,SSL3_AL_FATAL,al);
962 int dtls1_send_finished(SSL *s, int a, int b, const char *sender, int slen)
970 d=(unsigned char *)s->init_buf->data;
971 p= &(d[DTLS1_HM_HEADER_LENGTH]);
973 i=s->method->ssl3_enc->final_finish_mac(s,
974 sender,slen,s->s3->tmp.finish_md);
975 s->s3->tmp.finish_md_len = i;
976 memcpy(p, s->s3->tmp.finish_md, i);
980 /* Copy the finished so we can use it for
981 * renegotiation checks
983 if(s->type == SSL_ST_CONNECT)
985 OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
986 memcpy(s->s3->previous_client_finished,
987 s->s3->tmp.finish_md, i);
988 s->s3->previous_client_finished_len=i;
992 OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
993 memcpy(s->s3->previous_server_finished,
994 s->s3->tmp.finish_md, i);
995 s->s3->previous_server_finished_len=i;
998 #ifdef OPENSSL_SYS_WIN16
999 /* MSVC 1.5 does not clear the top bytes of the word unless
1005 d = dtls1_set_message_header(s, d, SSL3_MT_FINISHED, l, 0, l);
1006 s->init_num=(int)l+DTLS1_HM_HEADER_LENGTH;
1009 /* buffer the message to handle re-xmits */
1010 dtls1_buffer_message(s, 0);
1015 /* SSL3_ST_SEND_xxxxxx_HELLO_B */
1016 return(dtls1_do_write(s,SSL3_RT_HANDSHAKE));
1019 /* for these 2 messages, we need to
1020 * ssl->enc_read_ctx re-init
1021 * ssl->s3->read_sequence zero
1022 * ssl->s3->read_mac_secret re-init
1023 * ssl->session->read_sym_enc assign
1024 * ssl->session->read_compression assign
1025 * ssl->session->read_hash assign
1027 int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
1033 p=(unsigned char *)s->init_buf->data;
1035 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1036 s->init_num=DTLS1_CCS_HEADER_LENGTH;
1038 if (s->version == DTLS1_BAD_VER) {
1039 s->d1->next_handshake_write_seq++;
1040 s2n(s->d1->handshake_write_seq,p);
1046 dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
1047 s->d1->handshake_write_seq, 0, 0);
1049 /* buffer the message to handle re-xmits */
1050 dtls1_buffer_message(s, 1);
1055 /* SSL3_ST_CW_CHANGE_B */
1056 return(dtls1_do_write(s,SSL3_RT_CHANGE_CIPHER_SPEC));
1059 static int dtls1_add_cert_to_buf(BUF_MEM *buf, unsigned long *l, X509 *x)
1065 if (!BUF_MEM_grow_clean(buf,(int)(n+(*l)+3)))
1067 SSLerr(SSL_F_DTLS1_ADD_CERT_TO_BUF,ERR_R_BUF_LIB);
1070 p=(unsigned char *)&(buf->data[*l]);
1077 unsigned long dtls1_output_cert_chain(SSL *s, X509 *x)
1081 unsigned long l= 3 + DTLS1_HM_HEADER_LENGTH;
1084 /* TLSv1 sends a chain with nothing in it, instead of an alert */
1086 if (!BUF_MEM_grow_clean(buf,10))
1088 SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
1093 X509_STORE_CTX xs_ctx;
1095 if (!X509_STORE_CTX_init(&xs_ctx,s->ctx->cert_store,x,NULL))
1097 SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_X509_LIB);
1101 X509_verify_cert(&xs_ctx);
1102 /* Don't leave errors in the queue */
1104 for (i=0; i < sk_X509_num(xs_ctx.chain); i++)
1106 x = sk_X509_value(xs_ctx.chain, i);
1108 if (!dtls1_add_cert_to_buf(buf, &l, x))
1110 X509_STORE_CTX_cleanup(&xs_ctx);
1114 X509_STORE_CTX_cleanup(&xs_ctx);
1116 /* Thawte special :-) */
1117 for (i=0; i<sk_X509_num(s->ctx->extra_certs); i++)
1119 x=sk_X509_value(s->ctx->extra_certs,i);
1120 if (!dtls1_add_cert_to_buf(buf, &l, x))
1124 l-= (3 + DTLS1_HM_HEADER_LENGTH);
1126 p=(unsigned char *)&(buf->data[DTLS1_HM_HEADER_LENGTH]);
1129 p=(unsigned char *)&(buf->data[0]);
1130 p = dtls1_set_message_header(s, p, SSL3_MT_CERTIFICATE, l, 0, l);
1132 l+=DTLS1_HM_HEADER_LENGTH;
1136 int dtls1_read_failed(SSL *s, int code)
1140 fprintf( stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
1144 if (!dtls1_is_timer_expired(s))
1146 /* not a timeout, none of our business,
1147 let higher layers handle this. in fact it's probably an error */
1151 #ifndef OPENSSL_NO_HEARTBEATS
1152 if (!SSL_in_init(s) && !s->tlsext_hb_pending) /* done, no need to send a retransmit */
1154 if (!SSL_in_init(s)) /* done, no need to send a retransmit */
1157 BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
1161 #if 0 /* for now, each alert contains only one record number */
1162 item = pqueue_peek(state->rcvd_records);
1165 /* send an alert immediately for all the missing records */
1170 #if 0 /* no more alert sending, just retransmit the last set of messages */
1171 if ( state->timeout.read_timeouts >= DTLS1_TMO_READ_COUNT)
1172 ssl3_send_alert(s,SSL3_AL_WARNING,
1173 DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
1176 return dtls1_handle_timeout(s);
1180 dtls1_get_queue_priority(unsigned short seq, int is_ccs)
1182 /* The index of the retransmission queue actually is the message sequence number,
1183 * since the queue only contains messages of a single handshake. However, the
1184 * ChangeCipherSpec has no message sequence number and so using only the sequence
1185 * will result in the CCS and Finished having the same index. To prevent this,
1186 * the sequence number is multiplied by 2. In case of a CCS 1 is subtracted.
1187 * This does not only differ CSS and Finished, it also maintains the order of the
1188 * index (important for priority queues) and fits in the unsigned short variable.
1190 return seq * 2 - is_ccs;
1194 dtls1_retransmit_buffered_messages(SSL *s)
1196 pqueue sent = s->d1->sent_messages;
1202 iter = pqueue_iterator(sent);
1204 for ( item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter))
1206 frag = (hm_fragment *)item->data;
1207 if ( dtls1_retransmit_message(s,
1208 (unsigned short)dtls1_get_queue_priority(frag->msg_header.seq, frag->msg_header.is_ccs),
1209 0, &found) <= 0 && found)
1211 fprintf(stderr, "dtls1_retransmit_message() failed\n");
1220 dtls1_buffer_message(SSL *s, int is_ccs)
1224 unsigned char seq64be[8];
1226 /* this function is called immediately after a message has
1227 * been serialized */
1228 OPENSSL_assert(s->init_off == 0);
1230 frag = dtls1_hm_fragment_new(s->init_num, 0);
1234 memcpy(frag->fragment, s->init_buf->data, s->init_num);
1238 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1239 ((s->version==DTLS1_VERSION)?DTLS1_CCS_HEADER_LENGTH:3) == (unsigned int)s->init_num);
1243 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1244 DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num);
1247 frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
1248 frag->msg_header.seq = s->d1->w_msg_hdr.seq;
1249 frag->msg_header.type = s->d1->w_msg_hdr.type;
1250 frag->msg_header.frag_off = 0;
1251 frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
1252 frag->msg_header.is_ccs = is_ccs;
1254 /* save current state*/
1255 frag->msg_header.saved_retransmit_state.enc_write_ctx = s->enc_write_ctx;
1256 frag->msg_header.saved_retransmit_state.write_hash = s->write_hash;
1257 frag->msg_header.saved_retransmit_state.compress = s->compress;
1258 frag->msg_header.saved_retransmit_state.session = s->session;
1259 frag->msg_header.saved_retransmit_state.epoch = s->d1->w_epoch;
1261 memset(seq64be,0,sizeof(seq64be));
1262 seq64be[6] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1263 frag->msg_header.is_ccs)>>8);
1264 seq64be[7] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1265 frag->msg_header.is_ccs));
1267 item = pitem_new(seq64be, frag);
1270 dtls1_hm_fragment_free(frag);
1275 fprintf( stderr, "buffered messge: \ttype = %xx\n", msg_buf->type);
1276 fprintf( stderr, "\t\t\t\t\tlen = %d\n", msg_buf->len);
1277 fprintf( stderr, "\t\t\t\t\tseq_num = %d\n", msg_buf->seq_num);
1280 pqueue_insert(s->d1->sent_messages, item);
1285 dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
1289 /* XDTLS: for now assuming that read/writes are blocking */
1292 unsigned long header_length;
1293 unsigned char seq64be[8];
1294 struct dtls1_retransmit_state saved_state;
1295 unsigned char save_write_sequence[8];
1298 OPENSSL_assert(s->init_num == 0);
1299 OPENSSL_assert(s->init_off == 0);
1302 /* XDTLS: the requested message ought to be found, otherwise error */
1303 memset(seq64be,0,sizeof(seq64be));
1304 seq64be[6] = (unsigned char)(seq>>8);
1305 seq64be[7] = (unsigned char)seq;
1307 item = pqueue_find(s->d1->sent_messages, seq64be);
1310 fprintf(stderr, "retransmit: message %d non-existant\n", seq);
1316 frag = (hm_fragment *)item->data;
1318 if ( frag->msg_header.is_ccs)
1319 header_length = DTLS1_CCS_HEADER_LENGTH;
1321 header_length = DTLS1_HM_HEADER_LENGTH;
1323 memcpy(s->init_buf->data, frag->fragment,
1324 frag->msg_header.msg_len + header_length);
1325 s->init_num = frag->msg_header.msg_len + header_length;
1327 dtls1_set_message_header_int(s, frag->msg_header.type,
1328 frag->msg_header.msg_len, frag->msg_header.seq, 0,
1329 frag->msg_header.frag_len);
1331 /* save current state */
1332 saved_state.enc_write_ctx = s->enc_write_ctx;
1333 saved_state.write_hash = s->write_hash;
1334 saved_state.compress = s->compress;
1335 saved_state.session = s->session;
1336 saved_state.epoch = s->d1->w_epoch;
1337 saved_state.epoch = s->d1->w_epoch;
1339 s->d1->retransmitting = 1;
1341 /* restore state in which the message was originally sent */
1342 s->enc_write_ctx = frag->msg_header.saved_retransmit_state.enc_write_ctx;
1343 s->write_hash = frag->msg_header.saved_retransmit_state.write_hash;
1344 s->compress = frag->msg_header.saved_retransmit_state.compress;
1345 s->session = frag->msg_header.saved_retransmit_state.session;
1346 s->d1->w_epoch = frag->msg_header.saved_retransmit_state.epoch;
1348 if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1350 memcpy(save_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1351 memcpy(s->s3->write_sequence, s->d1->last_write_sequence, sizeof(s->s3->write_sequence));
1354 ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1355 SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1357 /* restore current state */
1358 s->enc_write_ctx = saved_state.enc_write_ctx;
1359 s->write_hash = saved_state.write_hash;
1360 s->compress = saved_state.compress;
1361 s->session = saved_state.session;
1362 s->d1->w_epoch = saved_state.epoch;
1364 if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1366 memcpy(s->d1->last_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1367 memcpy(s->s3->write_sequence, save_write_sequence, sizeof(s->s3->write_sequence));
1370 s->d1->retransmitting = 0;
1372 (void)BIO_flush(SSL_get_wbio(s));
1376 /* call this function when the buffered messages are no longer needed */
1378 dtls1_clear_record_buffer(SSL *s)
1382 for(item = pqueue_pop(s->d1->sent_messages);
1383 item != NULL; item = pqueue_pop(s->d1->sent_messages))
1385 dtls1_hm_fragment_free((hm_fragment *)item->data);
1392 dtls1_set_message_header(SSL *s, unsigned char *p, unsigned char mt,
1393 unsigned long len, unsigned long frag_off, unsigned long frag_len)
1395 /* Don't change sequence numbers while listening */
1396 if (frag_off == 0 && !s->d1->listen)
1398 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1399 s->d1->next_handshake_write_seq++;
1402 dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1403 frag_off, frag_len);
1405 return p += DTLS1_HM_HEADER_LENGTH;
1409 /* don't actually do the writing, wait till the MTU has been retrieved */
1411 dtls1_set_message_header_int(SSL *s, unsigned char mt,
1412 unsigned long len, unsigned short seq_num, unsigned long frag_off,
1413 unsigned long frag_len)
1415 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1418 msg_hdr->msg_len = len;
1419 msg_hdr->seq = seq_num;
1420 msg_hdr->frag_off = frag_off;
1421 msg_hdr->frag_len = frag_len;
1425 dtls1_fix_message_header(SSL *s, unsigned long frag_off,
1426 unsigned long frag_len)
1428 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1430 msg_hdr->frag_off = frag_off;
1431 msg_hdr->frag_len = frag_len;
1434 static unsigned char *
1435 dtls1_write_message_header(SSL *s, unsigned char *p)
1437 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1439 *p++ = msg_hdr->type;
1440 l2n3(msg_hdr->msg_len, p);
1442 s2n(msg_hdr->seq, p);
1443 l2n3(msg_hdr->frag_off, p);
1444 l2n3(msg_hdr->frag_len, p);
1450 dtls1_link_min_mtu(void)
1452 return (g_probable_mtu[(sizeof(g_probable_mtu) /
1453 sizeof(g_probable_mtu[0])) - 1]);
1457 dtls1_min_mtu(SSL *s)
1459 return dtls1_link_min_mtu()-BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
1464 dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
1466 memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
1467 msg_hdr->type = *(data++);
1468 n2l3(data, msg_hdr->msg_len);
1470 n2s(data, msg_hdr->seq);
1471 n2l3(data, msg_hdr->frag_off);
1472 n2l3(data, msg_hdr->frag_len);
1476 dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr)
1478 memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st));
1480 ccs_hdr->type = *(data++);
1483 int dtls1_shutdown(SSL *s)
1486 #ifndef OPENSSL_NO_SCTP
1487 if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
1488 !(s->shutdown & SSL_SENT_SHUTDOWN))
1490 ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
1491 if (ret < 0) return -1;
1494 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1, NULL);
1497 ret = ssl3_shutdown(s);
1498 #ifndef OPENSSL_NO_SCTP
1499 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
1504 #ifndef OPENSSL_NO_HEARTBEATS
1506 dtls1_process_heartbeat(SSL *s)
1508 unsigned char *p = &s->s3->rrec.data[0], *pl;
1509 unsigned short hbtype;
1510 unsigned int payload;
1511 unsigned int padding = 16; /* Use minimum padding */
1513 if (s->msg_callback)
1514 s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
1515 &s->s3->rrec.data[0], s->s3->rrec.length,
1516 s, s->msg_callback_arg);
1518 /* Read type and payload length first */
1519 if (1 + 2 + 16 > s->s3->rrec.length)
1520 return 0; /* silently discard */
1521 if (s->s3->rrec.length > SSL3_RT_MAX_PLAIN_LENGTH)
1522 return 0; /* silently discard per RFC 6520 sec. 4 */
1526 if (1 + 2 + payload + 16 > s->s3->rrec.length)
1527 return 0; /* silently discard per RFC 6520 sec. 4 */
1530 if (hbtype == TLS1_HB_REQUEST)
1532 unsigned char *buffer, *bp;
1533 unsigned int write_length = 1 /* heartbeat type */ +
1534 2 /* heartbeat length */ +
1538 if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
1541 /* Allocate memory for the response, size is 1 byte
1542 * message type, plus 2 bytes payload length, plus
1543 * payload, plus padding
1545 buffer = OPENSSL_malloc(write_length);
1548 /* Enter response type, length and copy payload */
1549 *bp++ = TLS1_HB_RESPONSE;
1551 memcpy(bp, pl, payload);
1553 /* Random padding */
1554 RAND_pseudo_bytes(bp, padding);
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,
1561 s, s->msg_callback_arg);
1563 OPENSSL_free(buffer);
1568 else if (hbtype == TLS1_HB_RESPONSE)
1572 /* We only send sequence numbers (2 bytes unsigned int),
1573 * and 16 random bytes, so we just try to read the
1574 * sequence number */
1577 if (payload == 18 && seq == s->tlsext_hb_seq)
1579 dtls1_stop_timer(s);
1581 s->tlsext_hb_pending = 0;
1589 dtls1_heartbeat(SSL *s)
1591 unsigned char *buf, *p;
1593 unsigned int payload = 18; /* Sequence number + random bytes */
1594 unsigned int padding = 16; /* Use minimum padding */
1596 /* Only send if peer supports and accepts HB requests... */
1597 if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
1598 s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS)
1600 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
1604 /* ...and there is none in flight yet... */
1605 if (s->tlsext_hb_pending)
1607 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PENDING);
1611 /* ...and no handshake in progress. */
1612 if (SSL_in_init(s) || s->in_handshake)
1614 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_UNEXPECTED_MESSAGE);
1618 /* Check if padding is too long, payload and padding
1619 * must not exceed 2^14 - 3 = 16381 bytes in total.
1621 OPENSSL_assert(payload + padding <= 16381);
1623 /* Create HeartBeat message, we just use a sequence number
1624 * as payload to distuingish different messages and add
1625 * some random stuff.
1626 * - Message Type, 1 byte
1627 * - Payload Length, 2 bytes (unsigned int)
1628 * - Payload, the sequence number (2 bytes uint)
1629 * - Payload, random bytes (16 bytes uint)
1632 buf = OPENSSL_malloc(1 + 2 + payload + padding);
1635 *p++ = TLS1_HB_REQUEST;
1636 /* Payload length (18 bytes here) */
1638 /* Sequence number */
1639 s2n(s->tlsext_hb_seq, p);
1640 /* 16 random bytes */
1641 RAND_pseudo_bytes(p, 16);
1643 /* Random padding */
1644 RAND_pseudo_bytes(p, padding);
1646 ret = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buf, 3 + payload + padding);
1649 if (s->msg_callback)
1650 s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1651 buf, 3 + payload + padding,
1652 s, s->msg_callback_arg);
1654 dtls1_start_timer(s);
1655 s->tlsext_hb_pending = 1;