d1_both.c revision 267258
1/* ssl/d1_both.c */
2/*
3 * DTLS implementation written by Nagendra Modadugu
4 * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
5 */
6/* ====================================================================
7 * Copyright (c) 1998-2005 The OpenSSL Project.  All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 *
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 *
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
19 *    distribution.
20 *
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/)"
25 *
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.
30 *
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.
34 *
35 * 6. Redistributions of any form whatsoever must retain the following
36 *    acknowledgment:
37 *    "This product includes software developed by the OpenSSL Project
38 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
39 *
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 * ====================================================================
53 *
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).
57 *
58 */
59/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
60 * All rights reserved.
61 *
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.
65 *
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).
72 *
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.
79 *
80 * Redistribution and use in source and binary forms, with or without
81 * modification, are permitted provided that the following conditions
82 * are met:
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)"
97 *
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
108 * SUCH DAMAGE.
109 *
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.]
114 */
115
116#include <limits.h>
117#include <string.h>
118#include <stdio.h>
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>
125
126#define RSMBLY_BITMASK_SIZE(msg_len) (((msg_len) + 7) / 8)
127
128#define RSMBLY_BITMASK_MARK(bitmask, start, end) { \
129			if ((end) - (start) <= 8) { \
130				long ii; \
131				for (ii = (start); ii < (end); ii++) bitmask[((ii) >> 3)] |= (1 << ((ii) & 7)); \
132			} else { \
133				long ii; \
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)]; \
137			} }
138
139#define RSMBLY_BITMASK_IS_COMPLETE(bitmask, msg_len, is_complete) { \
140			long ii; \
141			OPENSSL_assert((msg_len) > 0); \
142			is_complete = 1; \
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; } }
146
147#if 0
148#define RSMBLY_BITMASK_PRINT(bitmask, msg_len) { \
149			long ii; \
150			printf("bitmask: "); for (ii = 0; ii < (msg_len); ii++) \
151			printf("%d ", (bitmask[ii >> 3] & (1 << (ii & 7))) >> (ii & 7)); \
152			printf("\n"); }
153#endif
154
155static unsigned char bitmask_start_values[] = {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80};
156static unsigned char bitmask_end_values[]   = {0xff, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f};
157
158/* XDTLS:  figure out the right values */
159static unsigned int g_probable_mtu[] = {1500 - 28, 512 - 28, 256 - 28};
160
161static unsigned int dtls1_guess_mtu(unsigned int curr_mtu);
162static void dtls1_fix_message_header(SSL *s, unsigned long frag_off,
163	unsigned long frag_len);
164static unsigned char *dtls1_write_message_header(SSL *s,
165	unsigned char *p);
166static void dtls1_set_message_header_int(SSL *s, unsigned char mt,
167	unsigned long len, unsigned short seq_num, unsigned long frag_off,
168	unsigned long frag_len);
169static long dtls1_get_message_fragment(SSL *s, int st1, int stn,
170	long max, int *ok);
171
172static hm_fragment *
173dtls1_hm_fragment_new(unsigned long frag_len, int reassembly)
174	{
175	hm_fragment *frag = NULL;
176	unsigned char *buf = NULL;
177	unsigned char *bitmask = NULL;
178
179	frag = (hm_fragment *)OPENSSL_malloc(sizeof(hm_fragment));
180	if ( frag == NULL)
181		return NULL;
182
183	if (frag_len)
184		{
185		buf = (unsigned char *)OPENSSL_malloc(frag_len);
186		if ( buf == NULL)
187			{
188			OPENSSL_free(frag);
189			return NULL;
190			}
191		}
192
193	/* zero length fragment gets zero frag->fragment */
194	frag->fragment = buf;
195
196	/* Initialize reassembly bitmask if necessary */
197	if (reassembly)
198		{
199		bitmask = (unsigned char *)OPENSSL_malloc(RSMBLY_BITMASK_SIZE(frag_len));
200		if (bitmask == NULL)
201			{
202			if (buf != NULL) OPENSSL_free(buf);
203			OPENSSL_free(frag);
204			return NULL;
205			}
206		memset(bitmask, 0, RSMBLY_BITMASK_SIZE(frag_len));
207		}
208
209	frag->reassembly = bitmask;
210
211	return frag;
212	}
213
214static void
215dtls1_hm_fragment_free(hm_fragment *frag)
216	{
217
218	if (frag->msg_header.is_ccs)
219		{
220		EVP_CIPHER_CTX_free(frag->msg_header.saved_retransmit_state.enc_write_ctx);
221		EVP_MD_CTX_destroy(frag->msg_header.saved_retransmit_state.write_hash);
222		}
223	if (frag->fragment) OPENSSL_free(frag->fragment);
224	if (frag->reassembly) OPENSSL_free(frag->reassembly);
225	OPENSSL_free(frag);
226	}
227
228/* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */
229int dtls1_do_write(SSL *s, int type)
230	{
231	int ret;
232	int curr_mtu;
233	unsigned int len, frag_off, mac_size, blocksize;
234
235	/* AHA!  Figure out the MTU, and stick to the right size */
236	if (s->d1->mtu < dtls1_min_mtu() && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))
237		{
238		s->d1->mtu =
239			BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
240
241		/* I've seen the kernel return bogus numbers when it doesn't know
242		 * (initial write), so just make sure we have a reasonable number */
243		if (s->d1->mtu < dtls1_min_mtu())
244			{
245			s->d1->mtu = 0;
246			s->d1->mtu = dtls1_guess_mtu(s->d1->mtu);
247			BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
248				s->d1->mtu, NULL);
249			}
250		}
251#if 0
252	mtu = s->d1->mtu;
253
254	fprintf(stderr, "using MTU = %d\n", mtu);
255
256	mtu -= (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
257
258	curr_mtu = mtu - BIO_wpending(SSL_get_wbio(s));
259
260	if ( curr_mtu > 0)
261		mtu = curr_mtu;
262	else if ( ( ret = BIO_flush(SSL_get_wbio(s))) <= 0)
263		return ret;
264
265	if ( BIO_wpending(SSL_get_wbio(s)) + s->init_num >= mtu)
266		{
267		ret = BIO_flush(SSL_get_wbio(s));
268		if ( ret <= 0)
269			return ret;
270		mtu = s->d1->mtu - (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
271		}
272#endif
273
274	OPENSSL_assert(s->d1->mtu >= dtls1_min_mtu());  /* should have something reasonable now */
275
276	if ( s->init_off == 0  && type == SSL3_RT_HANDSHAKE)
277		OPENSSL_assert(s->init_num ==
278			(int)s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH);
279
280	if (s->write_hash)
281		mac_size = EVP_MD_CTX_size(s->write_hash);
282	else
283		mac_size = 0;
284
285	if (s->enc_write_ctx &&
286		(EVP_CIPHER_mode( s->enc_write_ctx->cipher) & EVP_CIPH_CBC_MODE))
287		blocksize = 2 * EVP_CIPHER_block_size(s->enc_write_ctx->cipher);
288	else
289		blocksize = 0;
290
291	frag_off = 0;
292	while( s->init_num)
293		{
294		curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) -
295			DTLS1_RT_HEADER_LENGTH - mac_size - blocksize;
296
297		if ( curr_mtu <= DTLS1_HM_HEADER_LENGTH)
298			{
299			/* grr.. we could get an error if MTU picked was wrong */
300			ret = BIO_flush(SSL_get_wbio(s));
301			if ( ret <= 0)
302				return ret;
303			curr_mtu = s->d1->mtu - DTLS1_RT_HEADER_LENGTH -
304				mac_size - blocksize;
305			}
306
307		if ( s->init_num > curr_mtu)
308			len = curr_mtu;
309		else
310			len = s->init_num;
311
312
313		/* XDTLS: this function is too long.  split out the CCS part */
314		if ( type == SSL3_RT_HANDSHAKE)
315			{
316			if ( s->init_off != 0)
317				{
318				OPENSSL_assert(s->init_off > DTLS1_HM_HEADER_LENGTH);
319				s->init_off -= DTLS1_HM_HEADER_LENGTH;
320				s->init_num += DTLS1_HM_HEADER_LENGTH;
321
322				if ( s->init_num > curr_mtu)
323					len = curr_mtu;
324				else
325					len = s->init_num;
326				}
327
328			dtls1_fix_message_header(s, frag_off,
329				len - DTLS1_HM_HEADER_LENGTH);
330
331			dtls1_write_message_header(s, (unsigned char *)&s->init_buf->data[s->init_off]);
332
333			OPENSSL_assert(len >= DTLS1_HM_HEADER_LENGTH);
334			}
335
336		ret=dtls1_write_bytes(s,type,&s->init_buf->data[s->init_off],
337			len);
338		if (ret < 0)
339			{
340			/* might need to update MTU here, but we don't know
341			 * which previous packet caused the failure -- so can't
342			 * really retransmit anything.  continue as if everything
343			 * is fine and wait for an alert to handle the
344			 * retransmit
345			 */
346			if ( BIO_ctrl(SSL_get_wbio(s),
347				BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0 )
348				s->d1->mtu = BIO_ctrl(SSL_get_wbio(s),
349					BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
350			else
351				return(-1);
352			}
353		else
354			{
355
356			/* bad if this assert fails, only part of the handshake
357			 * message got sent.  but why would this happen? */
358			OPENSSL_assert(len == (unsigned int)ret);
359
360			if (type == SSL3_RT_HANDSHAKE && ! s->d1->retransmitting)
361				{
362				/* should not be done for 'Hello Request's, but in that case
363				 * we'll ignore the result anyway */
364				unsigned char *p = (unsigned char *)&s->init_buf->data[s->init_off];
365				const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
366				int xlen;
367
368				if (frag_off == 0 && s->version != DTLS1_BAD_VER)
369					{
370					/* reconstruct message header is if it
371					 * is being sent in single fragment */
372					*p++ = msg_hdr->type;
373					l2n3(msg_hdr->msg_len,p);
374					s2n (msg_hdr->seq,p);
375					l2n3(0,p);
376					l2n3(msg_hdr->msg_len,p);
377					p  -= DTLS1_HM_HEADER_LENGTH;
378					xlen = ret;
379					}
380				else
381					{
382					p  += DTLS1_HM_HEADER_LENGTH;
383					xlen = ret - DTLS1_HM_HEADER_LENGTH;
384					}
385
386				ssl3_finish_mac(s, p, xlen);
387				}
388
389			if (ret == s->init_num)
390				{
391				if (s->msg_callback)
392					s->msg_callback(1, s->version, type, s->init_buf->data,
393						(size_t)(s->init_off + s->init_num), s,
394						s->msg_callback_arg);
395
396				s->init_off = 0;  /* done writing this message */
397				s->init_num = 0;
398
399				return(1);
400				}
401			s->init_off+=ret;
402			s->init_num-=ret;
403			frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
404			}
405		}
406	return(0);
407	}
408
409
410/* Obtain handshake message of message type 'mt' (any if mt == -1),
411 * maximum acceptable body length 'max'.
412 * Read an entire handshake message.  Handshake messages arrive in
413 * fragments.
414 */
415long dtls1_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
416	{
417	int i, al;
418	struct hm_header_st *msg_hdr;
419	unsigned char *p;
420	unsigned long msg_len;
421
422	/* s3->tmp is used to store messages that are unexpected, caused
423	 * by the absence of an optional handshake message */
424	if (s->s3->tmp.reuse_message)
425		{
426		s->s3->tmp.reuse_message=0;
427		if ((mt >= 0) && (s->s3->tmp.message_type != mt))
428			{
429			al=SSL_AD_UNEXPECTED_MESSAGE;
430			SSLerr(SSL_F_DTLS1_GET_MESSAGE,SSL_R_UNEXPECTED_MESSAGE);
431			goto f_err;
432			}
433		*ok=1;
434		s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
435		s->init_num = (int)s->s3->tmp.message_size;
436		return s->init_num;
437		}
438
439	msg_hdr = &s->d1->r_msg_hdr;
440	memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
441
442again:
443	i = dtls1_get_message_fragment(s, st1, stn, max, ok);
444	if ( i == DTLS1_HM_BAD_FRAGMENT ||
445		i == DTLS1_HM_FRAGMENT_RETRY)  /* bad fragment received */
446		goto again;
447	else if ( i <= 0 && !*ok)
448		return i;
449
450	p = (unsigned char *)s->init_buf->data;
451	msg_len = msg_hdr->msg_len;
452
453	/* reconstruct message header */
454	*(p++) = msg_hdr->type;
455	l2n3(msg_len,p);
456	s2n (msg_hdr->seq,p);
457	l2n3(0,p);
458	l2n3(msg_len,p);
459	if (s->version != DTLS1_BAD_VER) {
460		p       -= DTLS1_HM_HEADER_LENGTH;
461		msg_len += DTLS1_HM_HEADER_LENGTH;
462	}
463
464	ssl3_finish_mac(s, p, msg_len);
465	if (s->msg_callback)
466		s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
467			p, msg_len,
468			s, s->msg_callback_arg);
469
470	memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
471
472	/* Don't change sequence numbers while listening */
473	if (!s->d1->listen)
474		s->d1->handshake_read_seq++;
475
476	s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
477	return s->init_num;
478
479f_err:
480	ssl3_send_alert(s,SSL3_AL_FATAL,al);
481	*ok = 0;
482	return -1;
483	}
484
485
486static int dtls1_preprocess_fragment(SSL *s,struct hm_header_st *msg_hdr,int max)
487	{
488	size_t frag_off,frag_len,msg_len;
489
490	msg_len  = msg_hdr->msg_len;
491	frag_off = msg_hdr->frag_off;
492	frag_len = msg_hdr->frag_len;
493
494	/* sanity checking */
495	if ( (frag_off+frag_len) > msg_len)
496		{
497		SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
498		return SSL_AD_ILLEGAL_PARAMETER;
499		}
500
501	if ( (frag_off+frag_len) > (unsigned long)max)
502		{
503		SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
504		return SSL_AD_ILLEGAL_PARAMETER;
505		}
506
507	if ( s->d1->r_msg_hdr.frag_off == 0) /* first fragment */
508		{
509		/* msg_len is limited to 2^24, but is effectively checked
510		 * against max above */
511		if (!BUF_MEM_grow_clean(s->init_buf,msg_len+DTLS1_HM_HEADER_LENGTH))
512			{
513			SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,ERR_R_BUF_LIB);
514			return SSL_AD_INTERNAL_ERROR;
515			}
516
517		s->s3->tmp.message_size  = msg_len;
518		s->d1->r_msg_hdr.msg_len = msg_len;
519		s->s3->tmp.message_type  = msg_hdr->type;
520		s->d1->r_msg_hdr.type    = msg_hdr->type;
521		s->d1->r_msg_hdr.seq     = msg_hdr->seq;
522		}
523	else if (msg_len != s->d1->r_msg_hdr.msg_len)
524		{
525		/* They must be playing with us! BTW, failure to enforce
526		 * upper limit would open possibility for buffer overrun. */
527		SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
528		return SSL_AD_ILLEGAL_PARAMETER;
529		}
530
531	return 0; /* no error */
532	}
533
534
535static int
536dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok)
537	{
538	/* (0) check whether the desired fragment is available
539	 * if so:
540	 * (1) copy over the fragment to s->init_buf->data[]
541	 * (2) update s->init_num
542	 */
543	pitem *item;
544	hm_fragment *frag;
545	int al;
546
547	*ok = 0;
548	item = pqueue_peek(s->d1->buffered_messages);
549	if ( item == NULL)
550		return 0;
551
552	frag = (hm_fragment *)item->data;
553
554	/* Don't return if reassembly still in progress */
555	if (frag->reassembly != NULL)
556		return 0;
557
558	if ( s->d1->handshake_read_seq == frag->msg_header.seq)
559		{
560		unsigned long frag_len = frag->msg_header.frag_len;
561		pqueue_pop(s->d1->buffered_messages);
562
563		al=dtls1_preprocess_fragment(s,&frag->msg_header,max);
564
565		if (al==0) /* no alert */
566			{
567			unsigned char *p = (unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
568			memcpy(&p[frag->msg_header.frag_off],
569				frag->fragment,frag->msg_header.frag_len);
570			}
571
572		dtls1_hm_fragment_free(frag);
573		pitem_free(item);
574
575		if (al==0)
576			{
577			*ok = 1;
578			return frag_len;
579			}
580
581		ssl3_send_alert(s,SSL3_AL_FATAL,al);
582		s->init_num = 0;
583		*ok = 0;
584		return -1;
585		}
586	else
587		return 0;
588	}
589
590
591static int
592dtls1_reassemble_fragment(SSL *s, struct hm_header_st* msg_hdr, int *ok)
593	{
594	hm_fragment *frag = NULL;
595	pitem *item = NULL;
596	int i = -1, is_complete;
597	unsigned char seq64be[8];
598	unsigned long frag_len = msg_hdr->frag_len, max_len;
599
600	if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len)
601		goto err;
602
603	/* Determine maximum allowed message size. Depends on (user set)
604	 * maximum certificate length, but 16k is minimum.
605	 */
606	if (DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH < s->max_cert_list)
607		max_len = s->max_cert_list;
608	else
609		max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
610
611	if ((msg_hdr->frag_off+frag_len) > max_len)
612		goto err;
613
614	/* Try to find item in queue */
615	memset(seq64be,0,sizeof(seq64be));
616	seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
617	seq64be[7] = (unsigned char) msg_hdr->seq;
618	item = pqueue_find(s->d1->buffered_messages, seq64be);
619
620	if (item == NULL)
621		{
622		frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1);
623		if ( frag == NULL)
624			goto err;
625		memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
626		frag->msg_header.frag_len = frag->msg_header.msg_len;
627		frag->msg_header.frag_off = 0;
628		}
629	else
630		{
631		frag = (hm_fragment*) item->data;
632		if (frag->msg_header.msg_len != msg_hdr->msg_len)
633			{
634			item = NULL;
635			frag = NULL;
636			goto err;
637			}
638		}
639
640
641	/* If message is already reassembled, this must be a
642	 * retransmit and can be dropped.
643	 */
644	if (frag->reassembly == NULL)
645		{
646		unsigned char devnull [256];
647
648		while (frag_len)
649			{
650			i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
651				devnull,
652				frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
653			if (i<=0) goto err;
654			frag_len -= i;
655			}
656		return DTLS1_HM_FRAGMENT_RETRY;
657		}
658
659	/* read the body of the fragment (header has already been read */
660	i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
661		frag->fragment + msg_hdr->frag_off,frag_len,0);
662	if (i<=0 || (unsigned long)i!=frag_len)
663		goto err;
664
665	RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off,
666	                    (long)(msg_hdr->frag_off + frag_len));
667
668	RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len,
669	                           is_complete);
670
671	if (is_complete)
672		{
673		OPENSSL_free(frag->reassembly);
674		frag->reassembly = NULL;
675		}
676
677	if (item == NULL)
678		{
679		memset(seq64be,0,sizeof(seq64be));
680		seq64be[6] = (unsigned char)(msg_hdr->seq>>8);
681		seq64be[7] = (unsigned char)(msg_hdr->seq);
682
683		item = pitem_new(seq64be, frag);
684		if (item == NULL)
685			{
686			i = -1;
687			goto err;
688			}
689
690		pqueue_insert(s->d1->buffered_messages, item);
691		}
692
693	return DTLS1_HM_FRAGMENT_RETRY;
694
695err:
696	if (frag != NULL) dtls1_hm_fragment_free(frag);
697	if (item != NULL) OPENSSL_free(item);
698	*ok = 0;
699	return i;
700	}
701
702
703static int
704dtls1_process_out_of_seq_message(SSL *s, struct hm_header_st* msg_hdr, int *ok)
705{
706	int i=-1;
707	hm_fragment *frag = NULL;
708	pitem *item = NULL;
709	unsigned char seq64be[8];
710	unsigned long frag_len = msg_hdr->frag_len;
711
712	if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len)
713		goto err;
714
715	/* Try to find item in queue, to prevent duplicate entries */
716	memset(seq64be,0,sizeof(seq64be));
717	seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
718	seq64be[7] = (unsigned char) msg_hdr->seq;
719	item = pqueue_find(s->d1->buffered_messages, seq64be);
720
721	/* If we already have an entry and this one is a fragment,
722	 * don't discard it and rather try to reassemble it.
723	 */
724	if (item != NULL && frag_len < msg_hdr->msg_len)
725		item = NULL;
726
727	/* Discard the message if sequence number was already there, is
728	 * too far in the future, already in the queue or if we received
729	 * a FINISHED before the SERVER_HELLO, which then must be a stale
730	 * retransmit.
731	 */
732	if (msg_hdr->seq <= s->d1->handshake_read_seq ||
733		msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL ||
734		(s->d1->handshake_read_seq == 0 && msg_hdr->type == SSL3_MT_FINISHED))
735		{
736		unsigned char devnull [256];
737
738		while (frag_len)
739			{
740			i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
741				devnull,
742				frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
743			if (i<=0) goto err;
744			frag_len -= i;
745			}
746		}
747	else
748		{
749		if (frag_len && frag_len < msg_hdr->msg_len)
750			return dtls1_reassemble_fragment(s, msg_hdr, ok);
751
752		frag = dtls1_hm_fragment_new(frag_len, 0);
753		if ( frag == NULL)
754			goto err;
755
756		memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
757
758		if (frag_len)
759			{
760			/* read the body of the fragment (header has already been read */
761			i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
762				frag->fragment,frag_len,0);
763			if (i<=0 || (unsigned long)i!=frag_len)
764				goto err;
765			}
766
767		memset(seq64be,0,sizeof(seq64be));
768		seq64be[6] = (unsigned char)(msg_hdr->seq>>8);
769		seq64be[7] = (unsigned char)(msg_hdr->seq);
770
771		item = pitem_new(seq64be, frag);
772		if ( item == NULL)
773			goto err;
774
775		pqueue_insert(s->d1->buffered_messages, item);
776		}
777
778	return DTLS1_HM_FRAGMENT_RETRY;
779
780err:
781	if ( frag != NULL) dtls1_hm_fragment_free(frag);
782	if ( item != NULL) OPENSSL_free(item);
783	*ok = 0;
784	return i;
785	}
786
787
788static long
789dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
790	{
791	unsigned char wire[DTLS1_HM_HEADER_LENGTH];
792	unsigned long len, frag_off, frag_len;
793	int i,al;
794	struct hm_header_st msg_hdr;
795
796	redo:
797	/* see if we have the required fragment already */
798	if ((frag_len = dtls1_retrieve_buffered_fragment(s,max,ok)) || *ok)
799		{
800		if (*ok)	s->init_num = frag_len;
801		return frag_len;
802		}
803
804	/* read handshake message header */
805	i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,wire,
806		DTLS1_HM_HEADER_LENGTH, 0);
807	if (i <= 0) 	/* nbio, or an error */
808		{
809		s->rwstate=SSL_READING;
810		*ok = 0;
811		return i;
812		}
813	/* Handshake fails if message header is incomplete */
814	if (i != DTLS1_HM_HEADER_LENGTH)
815		{
816		al=SSL_AD_UNEXPECTED_MESSAGE;
817		SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
818		goto f_err;
819		}
820
821	/* parse the message fragment header */
822	dtls1_get_message_header(wire, &msg_hdr);
823
824	/*
825	 * if this is a future (or stale) message it gets buffered
826	 * (or dropped)--no further processing at this time
827	 * While listening, we accept seq 1 (ClientHello with cookie)
828	 * although we're still expecting seq 0 (ClientHello)
829	 */
830	if (msg_hdr.seq != s->d1->handshake_read_seq && !(s->d1->listen && msg_hdr.seq == 1))
831		return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
832
833	len = msg_hdr.msg_len;
834	frag_off = msg_hdr.frag_off;
835	frag_len = msg_hdr.frag_len;
836
837	if (frag_len && frag_len < len)
838		return dtls1_reassemble_fragment(s, &msg_hdr, ok);
839
840	if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
841		wire[0] == SSL3_MT_HELLO_REQUEST)
842		{
843		/* The server may always send 'Hello Request' messages --
844		 * we are doing a handshake anyway now, so ignore them
845		 * if their format is correct. Does not count for
846		 * 'Finished' MAC. */
847		if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0)
848			{
849			if (s->msg_callback)
850				s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
851					wire, DTLS1_HM_HEADER_LENGTH, s,
852					s->msg_callback_arg);
853
854			s->init_num = 0;
855			goto redo;
856			}
857		else /* Incorrectly formated Hello request */
858			{
859			al=SSL_AD_UNEXPECTED_MESSAGE;
860			SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
861			goto f_err;
862			}
863		}
864
865	if ((al=dtls1_preprocess_fragment(s,&msg_hdr,max)))
866		goto f_err;
867
868	/* XDTLS:  ressurect this when restart is in place */
869	s->state=stn;
870
871	if ( frag_len > 0)
872		{
873		unsigned char *p=(unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
874
875		i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
876			&p[frag_off],frag_len,0);
877		/* XDTLS:  fix this--message fragments cannot span multiple packets */
878		if (i <= 0)
879			{
880			s->rwstate=SSL_READING;
881			*ok = 0;
882			return i;
883			}
884		}
885	else
886		i = 0;
887
888	/* XDTLS:  an incorrectly formatted fragment should cause the
889	 * handshake to fail */
890	if (i != (int)frag_len)
891		{
892		al=SSL3_AD_ILLEGAL_PARAMETER;
893		SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL3_AD_ILLEGAL_PARAMETER);
894		goto f_err;
895		}
896
897	*ok = 1;
898
899	/* Note that s->init_num is *not* used as current offset in
900	 * s->init_buf->data, but as a counter summing up fragments'
901	 * lengths: as soon as they sum up to handshake packet
902	 * length, we assume we have got all the fragments. */
903	s->init_num = frag_len;
904	return frag_len;
905
906f_err:
907	ssl3_send_alert(s,SSL3_AL_FATAL,al);
908	s->init_num = 0;
909
910	*ok=0;
911	return(-1);
912	}
913
914int dtls1_send_finished(SSL *s, int a, int b, const char *sender, int slen)
915	{
916	unsigned char *p,*d;
917	int i;
918	unsigned long l;
919
920	if (s->state == a)
921		{
922		d=(unsigned char *)s->init_buf->data;
923		p= &(d[DTLS1_HM_HEADER_LENGTH]);
924
925		i=s->method->ssl3_enc->final_finish_mac(s,
926			sender,slen,s->s3->tmp.finish_md);
927		s->s3->tmp.finish_md_len = i;
928		memcpy(p, s->s3->tmp.finish_md, i);
929		p+=i;
930		l=i;
931
932	/* Copy the finished so we can use it for
933	 * renegotiation checks
934	 */
935	if(s->type == SSL_ST_CONNECT)
936		{
937		OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
938		memcpy(s->s3->previous_client_finished,
939		       s->s3->tmp.finish_md, i);
940		s->s3->previous_client_finished_len=i;
941		}
942	else
943		{
944		OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
945		memcpy(s->s3->previous_server_finished,
946		       s->s3->tmp.finish_md, i);
947		s->s3->previous_server_finished_len=i;
948		}
949
950#ifdef OPENSSL_SYS_WIN16
951		/* MSVC 1.5 does not clear the top bytes of the word unless
952		 * I do this.
953		 */
954		l&=0xffff;
955#endif
956
957		d = dtls1_set_message_header(s, d, SSL3_MT_FINISHED, l, 0, l);
958		s->init_num=(int)l+DTLS1_HM_HEADER_LENGTH;
959		s->init_off=0;
960
961		/* buffer the message to handle re-xmits */
962		dtls1_buffer_message(s, 0);
963
964		s->state=b;
965		}
966
967	/* SSL3_ST_SEND_xxxxxx_HELLO_B */
968	return(dtls1_do_write(s,SSL3_RT_HANDSHAKE));
969	}
970
971/* for these 2 messages, we need to
972 * ssl->enc_read_ctx			re-init
973 * ssl->s3->read_sequence		zero
974 * ssl->s3->read_mac_secret		re-init
975 * ssl->session->read_sym_enc		assign
976 * ssl->session->read_compression	assign
977 * ssl->session->read_hash		assign
978 */
979int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
980	{
981	unsigned char *p;
982
983	if (s->state == a)
984		{
985		p=(unsigned char *)s->init_buf->data;
986		*p++=SSL3_MT_CCS;
987		s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
988		s->init_num=DTLS1_CCS_HEADER_LENGTH;
989
990		if (s->version == DTLS1_BAD_VER) {
991			s->d1->next_handshake_write_seq++;
992			s2n(s->d1->handshake_write_seq,p);
993			s->init_num+=2;
994		}
995
996		s->init_off=0;
997
998		dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
999			s->d1->handshake_write_seq, 0, 0);
1000
1001		/* buffer the message to handle re-xmits */
1002		dtls1_buffer_message(s, 1);
1003
1004		s->state=b;
1005		}
1006
1007	/* SSL3_ST_CW_CHANGE_B */
1008	return(dtls1_do_write(s,SSL3_RT_CHANGE_CIPHER_SPEC));
1009	}
1010
1011static int dtls1_add_cert_to_buf(BUF_MEM *buf, unsigned long *l, X509 *x)
1012	{
1013	int n;
1014	unsigned char *p;
1015
1016	n=i2d_X509(x,NULL);
1017	if (!BUF_MEM_grow_clean(buf,(int)(n+(*l)+3)))
1018		{
1019		SSLerr(SSL_F_DTLS1_ADD_CERT_TO_BUF,ERR_R_BUF_LIB);
1020		return 0;
1021		}
1022	p=(unsigned char *)&(buf->data[*l]);
1023	l2n3(n,p);
1024	i2d_X509(x,&p);
1025	*l+=n+3;
1026
1027	return 1;
1028	}
1029unsigned long dtls1_output_cert_chain(SSL *s, X509 *x)
1030	{
1031	unsigned char *p;
1032	int i;
1033	unsigned long l= 3 + DTLS1_HM_HEADER_LENGTH;
1034	BUF_MEM *buf;
1035
1036	/* TLSv1 sends a chain with nothing in it, instead of an alert */
1037	buf=s->init_buf;
1038	if (!BUF_MEM_grow_clean(buf,10))
1039		{
1040		SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
1041		return(0);
1042		}
1043	if (x != NULL)
1044		{
1045		X509_STORE_CTX xs_ctx;
1046
1047		if (!X509_STORE_CTX_init(&xs_ctx,s->ctx->cert_store,x,NULL))
1048  			{
1049  			SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_X509_LIB);
1050  			return(0);
1051  			}
1052
1053		X509_verify_cert(&xs_ctx);
1054		/* Don't leave errors in the queue */
1055		ERR_clear_error();
1056		for (i=0; i < sk_X509_num(xs_ctx.chain); i++)
1057  			{
1058			x = sk_X509_value(xs_ctx.chain, i);
1059
1060			if (!dtls1_add_cert_to_buf(buf, &l, x))
1061  				{
1062				X509_STORE_CTX_cleanup(&xs_ctx);
1063				return 0;
1064  				}
1065  			}
1066  		X509_STORE_CTX_cleanup(&xs_ctx);
1067  		}
1068  	/* Thawte special :-) */
1069	for (i=0; i<sk_X509_num(s->ctx->extra_certs); i++)
1070		{
1071		x=sk_X509_value(s->ctx->extra_certs,i);
1072		if (!dtls1_add_cert_to_buf(buf, &l, x))
1073			return 0;
1074		}
1075
1076	l-= (3 + DTLS1_HM_HEADER_LENGTH);
1077
1078	p=(unsigned char *)&(buf->data[DTLS1_HM_HEADER_LENGTH]);
1079	l2n3(l,p);
1080	l+=3;
1081	p=(unsigned char *)&(buf->data[0]);
1082	p = dtls1_set_message_header(s, p, SSL3_MT_CERTIFICATE, l, 0, l);
1083
1084	l+=DTLS1_HM_HEADER_LENGTH;
1085	return(l);
1086	}
1087
1088int dtls1_read_failed(SSL *s, int code)
1089	{
1090	if ( code > 0)
1091		{
1092		fprintf( stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
1093		return 1;
1094		}
1095
1096	if (!dtls1_is_timer_expired(s))
1097		{
1098		/* not a timeout, none of our business,
1099		   let higher layers handle this.  in fact it's probably an error */
1100		return code;
1101		}
1102
1103#ifndef OPENSSL_NO_HEARTBEATS
1104	if (!SSL_in_init(s) && !s->tlsext_hb_pending)  /* done, no need to send a retransmit */
1105#else
1106	if (!SSL_in_init(s))  /* done, no need to send a retransmit */
1107#endif
1108		{
1109		BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
1110		return code;
1111		}
1112
1113#if 0 /* for now, each alert contains only one record number */
1114	item = pqueue_peek(state->rcvd_records);
1115	if ( item )
1116		{
1117		/* send an alert immediately for all the missing records */
1118		}
1119	else
1120#endif
1121
1122#if 0  /* no more alert sending, just retransmit the last set of messages */
1123	if ( state->timeout.read_timeouts >= DTLS1_TMO_READ_COUNT)
1124		ssl3_send_alert(s,SSL3_AL_WARNING,
1125			DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
1126#endif
1127
1128	return dtls1_handle_timeout(s);
1129	}
1130
1131int
1132dtls1_get_queue_priority(unsigned short seq, int is_ccs)
1133	{
1134	/* The index of the retransmission queue actually is the message sequence number,
1135	 * since the queue only contains messages of a single handshake. However, the
1136	 * ChangeCipherSpec has no message sequence number and so using only the sequence
1137	 * will result in the CCS and Finished having the same index. To prevent this,
1138	 * the sequence number is multiplied by 2. In case of a CCS 1 is subtracted.
1139	 * This does not only differ CSS and Finished, it also maintains the order of the
1140	 * index (important for priority queues) and fits in the unsigned short variable.
1141	 */
1142	return seq * 2 - is_ccs;
1143	}
1144
1145int
1146dtls1_retransmit_buffered_messages(SSL *s)
1147	{
1148	pqueue sent = s->d1->sent_messages;
1149	piterator iter;
1150	pitem *item;
1151	hm_fragment *frag;
1152	int found = 0;
1153
1154	iter = pqueue_iterator(sent);
1155
1156	for ( item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter))
1157		{
1158		frag = (hm_fragment *)item->data;
1159			if ( dtls1_retransmit_message(s,
1160				(unsigned short)dtls1_get_queue_priority(frag->msg_header.seq, frag->msg_header.is_ccs),
1161				0, &found) <= 0 && found)
1162			{
1163			fprintf(stderr, "dtls1_retransmit_message() failed\n");
1164			return -1;
1165			}
1166		}
1167
1168	return 1;
1169	}
1170
1171int
1172dtls1_buffer_message(SSL *s, int is_ccs)
1173	{
1174	pitem *item;
1175	hm_fragment *frag;
1176	unsigned char seq64be[8];
1177
1178	/* this function is called immediately after a message has
1179	 * been serialized */
1180	OPENSSL_assert(s->init_off == 0);
1181
1182	frag = dtls1_hm_fragment_new(s->init_num, 0);
1183
1184	memcpy(frag->fragment, s->init_buf->data, s->init_num);
1185
1186	if ( is_ccs)
1187		{
1188		OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1189			       ((s->version==DTLS1_VERSION)?DTLS1_CCS_HEADER_LENGTH:3) == (unsigned int)s->init_num);
1190		}
1191	else
1192		{
1193		OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1194			DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num);
1195		}
1196
1197	frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
1198	frag->msg_header.seq = s->d1->w_msg_hdr.seq;
1199	frag->msg_header.type = s->d1->w_msg_hdr.type;
1200	frag->msg_header.frag_off = 0;
1201	frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
1202	frag->msg_header.is_ccs = is_ccs;
1203
1204	/* save current state*/
1205	frag->msg_header.saved_retransmit_state.enc_write_ctx = s->enc_write_ctx;
1206	frag->msg_header.saved_retransmit_state.write_hash = s->write_hash;
1207	frag->msg_header.saved_retransmit_state.compress = s->compress;
1208	frag->msg_header.saved_retransmit_state.session = s->session;
1209	frag->msg_header.saved_retransmit_state.epoch = s->d1->w_epoch;
1210
1211	memset(seq64be,0,sizeof(seq64be));
1212	seq64be[6] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1213														  frag->msg_header.is_ccs)>>8);
1214	seq64be[7] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1215														  frag->msg_header.is_ccs));
1216
1217	item = pitem_new(seq64be, frag);
1218	if ( item == NULL)
1219		{
1220		dtls1_hm_fragment_free(frag);
1221		return 0;
1222		}
1223
1224#if 0
1225	fprintf( stderr, "buffered messge: \ttype = %xx\n", msg_buf->type);
1226	fprintf( stderr, "\t\t\t\t\tlen = %d\n", msg_buf->len);
1227	fprintf( stderr, "\t\t\t\t\tseq_num = %d\n", msg_buf->seq_num);
1228#endif
1229
1230	pqueue_insert(s->d1->sent_messages, item);
1231	return 1;
1232	}
1233
1234int
1235dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
1236	int *found)
1237	{
1238	int ret;
1239	/* XDTLS: for now assuming that read/writes are blocking */
1240	pitem *item;
1241	hm_fragment *frag ;
1242	unsigned long header_length;
1243	unsigned char seq64be[8];
1244	struct dtls1_retransmit_state saved_state;
1245	unsigned char save_write_sequence[8];
1246
1247	/*
1248	  OPENSSL_assert(s->init_num == 0);
1249	  OPENSSL_assert(s->init_off == 0);
1250	 */
1251
1252	/* XDTLS:  the requested message ought to be found, otherwise error */
1253	memset(seq64be,0,sizeof(seq64be));
1254	seq64be[6] = (unsigned char)(seq>>8);
1255	seq64be[7] = (unsigned char)seq;
1256
1257	item = pqueue_find(s->d1->sent_messages, seq64be);
1258	if ( item == NULL)
1259		{
1260		fprintf(stderr, "retransmit:  message %d non-existant\n", seq);
1261		*found = 0;
1262		return 0;
1263		}
1264
1265	*found = 1;
1266	frag = (hm_fragment *)item->data;
1267
1268	if ( frag->msg_header.is_ccs)
1269		header_length = DTLS1_CCS_HEADER_LENGTH;
1270	else
1271		header_length = DTLS1_HM_HEADER_LENGTH;
1272
1273	memcpy(s->init_buf->data, frag->fragment,
1274		frag->msg_header.msg_len + header_length);
1275		s->init_num = frag->msg_header.msg_len + header_length;
1276
1277	dtls1_set_message_header_int(s, frag->msg_header.type,
1278		frag->msg_header.msg_len, frag->msg_header.seq, 0,
1279		frag->msg_header.frag_len);
1280
1281	/* save current state */
1282	saved_state.enc_write_ctx = s->enc_write_ctx;
1283	saved_state.write_hash = s->write_hash;
1284	saved_state.compress = s->compress;
1285	saved_state.session = s->session;
1286	saved_state.epoch = s->d1->w_epoch;
1287	saved_state.epoch = s->d1->w_epoch;
1288
1289	s->d1->retransmitting = 1;
1290
1291	/* restore state in which the message was originally sent */
1292	s->enc_write_ctx = frag->msg_header.saved_retransmit_state.enc_write_ctx;
1293	s->write_hash = frag->msg_header.saved_retransmit_state.write_hash;
1294	s->compress = frag->msg_header.saved_retransmit_state.compress;
1295	s->session = frag->msg_header.saved_retransmit_state.session;
1296	s->d1->w_epoch = frag->msg_header.saved_retransmit_state.epoch;
1297
1298	if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1299	{
1300		memcpy(save_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1301		memcpy(s->s3->write_sequence, s->d1->last_write_sequence, sizeof(s->s3->write_sequence));
1302	}
1303
1304	ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1305						 SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1306
1307	/* restore current state */
1308	s->enc_write_ctx = saved_state.enc_write_ctx;
1309	s->write_hash = saved_state.write_hash;
1310	s->compress = saved_state.compress;
1311	s->session = saved_state.session;
1312	s->d1->w_epoch = saved_state.epoch;
1313
1314	if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1315	{
1316		memcpy(s->d1->last_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1317		memcpy(s->s3->write_sequence, save_write_sequence, sizeof(s->s3->write_sequence));
1318	}
1319
1320	s->d1->retransmitting = 0;
1321
1322	(void)BIO_flush(SSL_get_wbio(s));
1323	return ret;
1324	}
1325
1326/* call this function when the buffered messages are no longer needed */
1327void
1328dtls1_clear_record_buffer(SSL *s)
1329	{
1330	pitem *item;
1331
1332	for(item = pqueue_pop(s->d1->sent_messages);
1333		item != NULL; item = pqueue_pop(s->d1->sent_messages))
1334		{
1335		dtls1_hm_fragment_free((hm_fragment *)item->data);
1336		pitem_free(item);
1337		}
1338	}
1339
1340
1341unsigned char *
1342dtls1_set_message_header(SSL *s, unsigned char *p, unsigned char mt,
1343			unsigned long len, unsigned long frag_off, unsigned long frag_len)
1344	{
1345	/* Don't change sequence numbers while listening */
1346	if (frag_off == 0 && !s->d1->listen)
1347		{
1348		s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1349		s->d1->next_handshake_write_seq++;
1350		}
1351
1352	dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1353		frag_off, frag_len);
1354
1355	return p += DTLS1_HM_HEADER_LENGTH;
1356	}
1357
1358
1359/* don't actually do the writing, wait till the MTU has been retrieved */
1360static void
1361dtls1_set_message_header_int(SSL *s, unsigned char mt,
1362			    unsigned long len, unsigned short seq_num, unsigned long frag_off,
1363			    unsigned long frag_len)
1364	{
1365	struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1366
1367	msg_hdr->type = mt;
1368	msg_hdr->msg_len = len;
1369	msg_hdr->seq = seq_num;
1370	msg_hdr->frag_off = frag_off;
1371	msg_hdr->frag_len = frag_len;
1372	}
1373
1374static void
1375dtls1_fix_message_header(SSL *s, unsigned long frag_off,
1376			unsigned long frag_len)
1377	{
1378	struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1379
1380	msg_hdr->frag_off = frag_off;
1381	msg_hdr->frag_len = frag_len;
1382	}
1383
1384static unsigned char *
1385dtls1_write_message_header(SSL *s, unsigned char *p)
1386	{
1387	struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1388
1389	*p++ = msg_hdr->type;
1390	l2n3(msg_hdr->msg_len, p);
1391
1392	s2n(msg_hdr->seq, p);
1393	l2n3(msg_hdr->frag_off, p);
1394	l2n3(msg_hdr->frag_len, p);
1395
1396	return p;
1397	}
1398
1399unsigned int
1400dtls1_min_mtu(void)
1401	{
1402	return (g_probable_mtu[(sizeof(g_probable_mtu) /
1403		sizeof(g_probable_mtu[0])) - 1]);
1404	}
1405
1406static unsigned int
1407dtls1_guess_mtu(unsigned int curr_mtu)
1408	{
1409	unsigned int i;
1410
1411	if ( curr_mtu == 0 )
1412		return g_probable_mtu[0] ;
1413
1414	for ( i = 0; i < sizeof(g_probable_mtu)/sizeof(g_probable_mtu[0]); i++)
1415		if ( curr_mtu > g_probable_mtu[i])
1416			return g_probable_mtu[i];
1417
1418	return curr_mtu;
1419	}
1420
1421void
1422dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
1423	{
1424	memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
1425	msg_hdr->type = *(data++);
1426	n2l3(data, msg_hdr->msg_len);
1427
1428	n2s(data, msg_hdr->seq);
1429	n2l3(data, msg_hdr->frag_off);
1430	n2l3(data, msg_hdr->frag_len);
1431	}
1432
1433void
1434dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr)
1435	{
1436	memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st));
1437
1438	ccs_hdr->type = *(data++);
1439	}
1440
1441int dtls1_shutdown(SSL *s)
1442	{
1443	int ret;
1444#ifndef OPENSSL_NO_SCTP
1445	if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
1446	    !(s->shutdown & SSL_SENT_SHUTDOWN))
1447		{
1448		ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
1449		if (ret < 0) return -1;
1450
1451		if (ret == 0)
1452			BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1, NULL);
1453		}
1454#endif
1455	ret = ssl3_shutdown(s);
1456#ifndef OPENSSL_NO_SCTP
1457	BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
1458#endif
1459	return ret;
1460	}
1461
1462#ifndef OPENSSL_NO_HEARTBEATS
1463int
1464dtls1_process_heartbeat(SSL *s)
1465	{
1466	unsigned char *p = &s->s3->rrec.data[0], *pl;
1467	unsigned short hbtype;
1468	unsigned int payload;
1469	unsigned int padding = 16; /* Use minimum padding */
1470
1471	if (s->msg_callback)
1472		s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
1473			&s->s3->rrec.data[0], s->s3->rrec.length,
1474			s, s->msg_callback_arg);
1475
1476	/* Read type and payload length first */
1477	if (1 + 2 + 16 > s->s3->rrec.length)
1478		return 0; /* silently discard */
1479	hbtype = *p++;
1480	n2s(p, payload);
1481	if (1 + 2 + payload + 16 > s->s3->rrec.length)
1482		return 0; /* silently discard per RFC 6520 sec. 4 */
1483	pl = p;
1484
1485	if (hbtype == TLS1_HB_REQUEST)
1486		{
1487		unsigned char *buffer, *bp;
1488		unsigned int write_length = 1 /* heartbeat type */ +
1489					    2 /* heartbeat length */ +
1490					    payload + padding;
1491		int r;
1492
1493		if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
1494			return 0;
1495
1496		/* Allocate memory for the response, size is 1 byte
1497		 * message type, plus 2 bytes payload length, plus
1498		 * payload, plus padding
1499		 */
1500		buffer = OPENSSL_malloc(write_length);
1501		bp = buffer;
1502
1503		/* Enter response type, length and copy payload */
1504		*bp++ = TLS1_HB_RESPONSE;
1505		s2n(payload, bp);
1506		memcpy(bp, pl, payload);
1507		bp += payload;
1508		/* Random padding */
1509		RAND_pseudo_bytes(bp, padding);
1510
1511		r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, write_length);
1512
1513		if (r >= 0 && s->msg_callback)
1514			s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1515				buffer, write_length,
1516				s, s->msg_callback_arg);
1517
1518		OPENSSL_free(buffer);
1519
1520		if (r < 0)
1521			return r;
1522		}
1523	else if (hbtype == TLS1_HB_RESPONSE)
1524		{
1525		unsigned int seq;
1526
1527		/* We only send sequence numbers (2 bytes unsigned int),
1528		 * and 16 random bytes, so we just try to read the
1529		 * sequence number */
1530		n2s(pl, seq);
1531
1532		if (payload == 18 && seq == s->tlsext_hb_seq)
1533			{
1534			dtls1_stop_timer(s);
1535			s->tlsext_hb_seq++;
1536			s->tlsext_hb_pending = 0;
1537			}
1538		}
1539
1540	return 0;
1541	}
1542
1543int
1544dtls1_heartbeat(SSL *s)
1545	{
1546	unsigned char *buf, *p;
1547	int ret;
1548	unsigned int payload = 18; /* Sequence number + random bytes */
1549	unsigned int padding = 16; /* Use minimum padding */
1550
1551	/* Only send if peer supports and accepts HB requests... */
1552	if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
1553	    s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS)
1554		{
1555		SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
1556		return -1;
1557		}
1558
1559	/* ...and there is none in flight yet... */
1560	if (s->tlsext_hb_pending)
1561		{
1562		SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PENDING);
1563		return -1;
1564		}
1565
1566	/* ...and no handshake in progress. */
1567	if (SSL_in_init(s) || s->in_handshake)
1568		{
1569		SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_UNEXPECTED_MESSAGE);
1570		return -1;
1571		}
1572
1573	/* Check if padding is too long, payload and padding
1574	 * must not exceed 2^14 - 3 = 16381 bytes in total.
1575	 */
1576	OPENSSL_assert(payload + padding <= 16381);
1577
1578	/* Create HeartBeat message, we just use a sequence number
1579	 * as payload to distuingish different messages and add
1580	 * some random stuff.
1581	 *  - Message Type, 1 byte
1582	 *  - Payload Length, 2 bytes (unsigned int)
1583	 *  - Payload, the sequence number (2 bytes uint)
1584	 *  - Payload, random bytes (16 bytes uint)
1585	 *  - Padding
1586	 */
1587	buf = OPENSSL_malloc(1 + 2 + payload + padding);
1588	p = buf;
1589	/* Message Type */
1590	*p++ = TLS1_HB_REQUEST;
1591	/* Payload length (18 bytes here) */
1592	s2n(payload, p);
1593	/* Sequence number */
1594	s2n(s->tlsext_hb_seq, p);
1595	/* 16 random bytes */
1596	RAND_pseudo_bytes(p, 16);
1597	p += 16;
1598	/* Random padding */
1599	RAND_pseudo_bytes(p, padding);
1600
1601	ret = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buf, 3 + payload + padding);
1602	if (ret >= 0)
1603		{
1604		if (s->msg_callback)
1605			s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1606				buf, 3 + payload + padding,
1607				s, s->msg_callback_arg);
1608
1609		dtls1_start_timer(s);
1610		s->tlsext_hb_pending = 1;
1611		}
1612
1613	OPENSSL_free(buf);
1614
1615	return ret;
1616	}
1617#endif
1618