1 /* $OpenBSD: d1_both.c,v 1.81 2022/02/05 14:54:10 jsing Exp $ */
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 <stdio.h>
118 #include <string.h>
119
120 #include <openssl/buffer.h>
121 #include <openssl/evp.h>
122 #include <openssl/objects.h>
123 #include <openssl/x509.h>
124
125 #include "bytestring.h"
126 #include "dtls_locl.h"
127 #include "pqueue.h"
128 #include "ssl_locl.h"
129
130 #define RSMBLY_BITMASK_SIZE(msg_len) (((msg_len) + 7) / 8)
131
132 #define RSMBLY_BITMASK_MARK(bitmask, start, end) { \
133 if ((end) - (start) <= 8) { \
134 long ii; \
135 for (ii = (start); ii < (end); ii++) bitmask[((ii) >> 3)] |= (1 << ((ii) & 7)); \
136 } else { \
137 long ii; \
138 bitmask[((start) >> 3)] |= bitmask_start_values[((start) & 7)]; \
139 for (ii = (((start) >> 3) + 1); ii < ((((end) - 1)) >> 3); ii++) bitmask[ii] = 0xff; \
140 bitmask[(((end) - 1) >> 3)] |= bitmask_end_values[((end) & 7)]; \
141 } }
142
143 #define RSMBLY_BITMASK_IS_COMPLETE(bitmask, msg_len, is_complete) { \
144 long ii; \
145 OPENSSL_assert((msg_len) > 0); \
146 is_complete = 1; \
147 if (bitmask[(((msg_len) - 1) >> 3)] != bitmask_end_values[((msg_len) & 7)]) is_complete = 0; \
148 if (is_complete) for (ii = (((msg_len) - 1) >> 3) - 1; ii >= 0 ; ii--) \
149 if (bitmask[ii] != 0xff) { is_complete = 0; break; } }
150
151 static const unsigned char bitmask_start_values[] = {
152 0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80
153 };
154 static const unsigned char bitmask_end_values[] = {
155 0xff, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f
156 };
157
158 /* XDTLS: figure out the right values */
159 static const unsigned int g_probable_mtu[] = {1500 - 28, 512 - 28, 256 - 28};
160
161 static unsigned int dtls1_guess_mtu(unsigned int curr_mtu);
162 static void dtls1_fix_message_header(SSL *s, unsigned long frag_off,
163 unsigned long frag_len);
164 static int dtls1_write_message_header(const struct hm_header_st *msg_hdr,
165 unsigned long frag_off, unsigned long frag_len, unsigned char *p);
166 static long dtls1_get_message_fragment(SSL *s, int st1, int stn, long max,
167 int *ok);
168
169 void dtls1_hm_fragment_free(hm_fragment *frag);
170
171 static hm_fragment *
dtls1_hm_fragment_new(unsigned long frag_len,int reassembly)172 dtls1_hm_fragment_new(unsigned long frag_len, int reassembly)
173 {
174 hm_fragment *frag;
175
176 if ((frag = calloc(1, sizeof(*frag))) == NULL)
177 goto err;
178
179 if (frag_len > 0) {
180 if ((frag->fragment = calloc(1, frag_len)) == NULL)
181 goto err;
182 }
183
184 /* Initialize reassembly bitmask if necessary. */
185 if (reassembly) {
186 if ((frag->reassembly = calloc(1,
187 RSMBLY_BITMASK_SIZE(frag_len))) == NULL)
188 goto err;
189 }
190
191 return frag;
192
193 err:
194 dtls1_hm_fragment_free(frag);
195 return NULL;
196 }
197
198 void
dtls1_hm_fragment_free(hm_fragment * frag)199 dtls1_hm_fragment_free(hm_fragment *frag)
200 {
201 if (frag == NULL)
202 return;
203
204 free(frag->fragment);
205 free(frag->reassembly);
206 free(frag);
207 }
208
209 /* send s->internal->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */
210 int
dtls1_do_write(SSL * s,int type)211 dtls1_do_write(SSL *s, int type)
212 {
213 int ret;
214 int curr_mtu;
215 unsigned int len, frag_off;
216 size_t overhead;
217
218 /* AHA! Figure out the MTU, and stick to the right size */
219 if (s->d1->mtu < dtls1_min_mtu() &&
220 !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
221 s->d1->mtu = BIO_ctrl(SSL_get_wbio(s),
222 BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
223
224 /*
225 * I've seen the kernel return bogus numbers when it
226 * doesn't know the MTU (ie., the initial write), so just
227 * make sure we have a reasonable number
228 */
229 if (s->d1->mtu < dtls1_min_mtu()) {
230 s->d1->mtu = 0;
231 s->d1->mtu = dtls1_guess_mtu(s->d1->mtu);
232 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
233 s->d1->mtu, NULL);
234 }
235 }
236
237 OPENSSL_assert(s->d1->mtu >= dtls1_min_mtu());
238 /* should have something reasonable now */
239
240 if (s->internal->init_off == 0 && type == SSL3_RT_HANDSHAKE)
241 OPENSSL_assert(s->internal->init_num ==
242 (int)s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH);
243
244 if (!tls12_record_layer_write_overhead(s->internal->rl, &overhead))
245 return -1;
246
247 frag_off = 0;
248 while (s->internal->init_num) {
249 curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) -
250 DTLS1_RT_HEADER_LENGTH - overhead;
251
252 if (curr_mtu <= DTLS1_HM_HEADER_LENGTH) {
253 /* grr.. we could get an error if MTU picked was wrong */
254 ret = BIO_flush(SSL_get_wbio(s));
255 if (ret <= 0)
256 return ret;
257 curr_mtu = s->d1->mtu - DTLS1_RT_HEADER_LENGTH -
258 overhead;
259 }
260
261 if (s->internal->init_num > curr_mtu)
262 len = curr_mtu;
263 else
264 len = s->internal->init_num;
265
266 /* XDTLS: this function is too long. split out the CCS part */
267 if (type == SSL3_RT_HANDSHAKE) {
268 if (s->internal->init_off != 0) {
269 OPENSSL_assert(s->internal->init_off > DTLS1_HM_HEADER_LENGTH);
270 s->internal->init_off -= DTLS1_HM_HEADER_LENGTH;
271 s->internal->init_num += DTLS1_HM_HEADER_LENGTH;
272
273 if (s->internal->init_num > curr_mtu)
274 len = curr_mtu;
275 else
276 len = s->internal->init_num;
277 }
278
279 dtls1_fix_message_header(s, frag_off,
280 len - DTLS1_HM_HEADER_LENGTH);
281
282 if (!dtls1_write_message_header(&s->d1->w_msg_hdr,
283 s->d1->w_msg_hdr.frag_off, s->d1->w_msg_hdr.frag_len,
284 (unsigned char *)&s->internal->init_buf->data[s->internal->init_off]))
285 return -1;
286
287 OPENSSL_assert(len >= DTLS1_HM_HEADER_LENGTH);
288 }
289
290 ret = dtls1_write_bytes(s, type,
291 &s->internal->init_buf->data[s->internal->init_off], len);
292 if (ret < 0) {
293 /*
294 * Might need to update MTU here, but we don't know
295 * which previous packet caused the failure -- so
296 * can't really retransmit anything. continue as
297 * if everything is fine and wait for an alert to
298 * handle the retransmit
299 */
300 if (BIO_ctrl(SSL_get_wbio(s),
301 BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0)
302 s->d1->mtu = BIO_ctrl(SSL_get_wbio(s),
303 BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
304 else
305 return (-1);
306 } else {
307
308 /*
309 * Bad if this assert fails, only part of the
310 * handshake message got sent. but why would
311 * this happen?
312 */
313 OPENSSL_assert(len == (unsigned int)ret);
314
315 if (type == SSL3_RT_HANDSHAKE &&
316 !s->d1->retransmitting) {
317 /*
318 * Should not be done for 'Hello Request's,
319 * but in that case we'll ignore the result
320 * anyway
321 */
322 unsigned char *p = (unsigned char *)&s->internal->init_buf->data[s->internal->init_off];
323 const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
324 int xlen;
325
326 if (frag_off == 0) {
327 /*
328 * Reconstruct message header is if it
329 * is being sent in single fragment
330 */
331 if (!dtls1_write_message_header(msg_hdr,
332 0, msg_hdr->msg_len, p))
333 return (-1);
334 xlen = ret;
335 } else {
336 p += DTLS1_HM_HEADER_LENGTH;
337 xlen = ret - DTLS1_HM_HEADER_LENGTH;
338 }
339
340 tls1_transcript_record(s, p, xlen);
341 }
342
343 if (ret == s->internal->init_num) {
344 if (s->internal->msg_callback)
345 s->internal->msg_callback(1, s->version, type,
346 s->internal->init_buf->data,
347 (size_t)(s->internal->init_off + s->internal->init_num),
348 s, s->internal->msg_callback_arg);
349
350 s->internal->init_off = 0;
351 /* done writing this message */
352 s->internal->init_num = 0;
353
354 return (1);
355 }
356 s->internal->init_off += ret;
357 s->internal->init_num -= ret;
358 frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
359 }
360 }
361 return (0);
362 }
363
364
365 /*
366 * Obtain handshake message of message type 'mt' (any if mt == -1),
367 * maximum acceptable body length 'max'.
368 * Read an entire handshake message. Handshake messages arrive in
369 * fragments.
370 */
371 int
dtls1_get_message(SSL * s,int st1,int stn,int mt,long max)372 dtls1_get_message(SSL *s, int st1, int stn, int mt, long max)
373 {
374 struct hm_header_st *msg_hdr;
375 unsigned char *p;
376 unsigned long msg_len;
377 int i, al, ok;
378
379 /*
380 * s3->internal->tmp is used to store messages that are unexpected, caused
381 * by the absence of an optional handshake message
382 */
383 if (s->s3->hs.tls12.reuse_message) {
384 s->s3->hs.tls12.reuse_message = 0;
385 if ((mt >= 0) && (s->s3->hs.tls12.message_type != mt)) {
386 al = SSL_AD_UNEXPECTED_MESSAGE;
387 SSLerror(s, SSL_R_UNEXPECTED_MESSAGE);
388 goto fatal_err;
389 }
390 s->internal->init_msg = s->internal->init_buf->data + DTLS1_HM_HEADER_LENGTH;
391 s->internal->init_num = (int)s->s3->hs.tls12.message_size;
392 return 1;
393 }
394
395 msg_hdr = &s->d1->r_msg_hdr;
396 memset(msg_hdr, 0, sizeof(struct hm_header_st));
397
398 again:
399 i = dtls1_get_message_fragment(s, st1, stn, max, &ok);
400 if (i == DTLS1_HM_BAD_FRAGMENT ||
401 i == DTLS1_HM_FRAGMENT_RETRY) /* bad fragment received */
402 goto again;
403 else if (i <= 0 && !ok)
404 return i;
405
406 p = (unsigned char *)s->internal->init_buf->data;
407 msg_len = msg_hdr->msg_len;
408
409 /* reconstruct message header */
410 if (!dtls1_write_message_header(msg_hdr, 0, msg_len, p))
411 return -1;
412
413 msg_len += DTLS1_HM_HEADER_LENGTH;
414
415 tls1_transcript_record(s, p, msg_len);
416 if (s->internal->msg_callback)
417 s->internal->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, p, msg_len,
418 s, s->internal->msg_callback_arg);
419
420 memset(msg_hdr, 0, sizeof(struct hm_header_st));
421
422 /* Don't change sequence numbers while listening */
423 if (!s->d1->listen)
424 s->d1->handshake_read_seq++;
425
426 s->internal->init_msg = s->internal->init_buf->data + DTLS1_HM_HEADER_LENGTH;
427 return 1;
428
429 fatal_err:
430 ssl3_send_alert(s, SSL3_AL_FATAL, al);
431 return -1;
432 }
433
434 static int
dtls1_preprocess_fragment(SSL * s,struct hm_header_st * msg_hdr,int max)435 dtls1_preprocess_fragment(SSL *s, struct hm_header_st *msg_hdr, int max)
436 {
437 size_t frag_off, frag_len, msg_len;
438
439 msg_len = msg_hdr->msg_len;
440 frag_off = msg_hdr->frag_off;
441 frag_len = msg_hdr->frag_len;
442
443 /* sanity checking */
444 if ((frag_off + frag_len) > msg_len) {
445 SSLerror(s, SSL_R_EXCESSIVE_MESSAGE_SIZE);
446 return SSL_AD_ILLEGAL_PARAMETER;
447 }
448
449 if ((frag_off + frag_len) > (unsigned long)max) {
450 SSLerror(s, SSL_R_EXCESSIVE_MESSAGE_SIZE);
451 return SSL_AD_ILLEGAL_PARAMETER;
452 }
453
454 if ( s->d1->r_msg_hdr.frag_off == 0) /* first fragment */
455 {
456 /*
457 * msg_len is limited to 2^24, but is effectively checked
458 * against max above
459 */
460 if (!BUF_MEM_grow_clean(s->internal->init_buf,
461 msg_len + DTLS1_HM_HEADER_LENGTH)) {
462 SSLerror(s, ERR_R_BUF_LIB);
463 return SSL_AD_INTERNAL_ERROR;
464 }
465
466 s->s3->hs.tls12.message_size = msg_len;
467 s->d1->r_msg_hdr.msg_len = msg_len;
468 s->s3->hs.tls12.message_type = msg_hdr->type;
469 s->d1->r_msg_hdr.type = msg_hdr->type;
470 s->d1->r_msg_hdr.seq = msg_hdr->seq;
471 } else if (msg_len != s->d1->r_msg_hdr.msg_len) {
472 /*
473 * They must be playing with us! BTW, failure to enforce
474 * upper limit would open possibility for buffer overrun.
475 */
476 SSLerror(s, SSL_R_EXCESSIVE_MESSAGE_SIZE);
477 return SSL_AD_ILLEGAL_PARAMETER;
478 }
479
480 return 0; /* no error */
481 }
482
483 static int
dtls1_retrieve_buffered_fragment(SSL * s,long max,int * ok)484 dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok)
485 {
486 /*
487 * (0) check whether the desired fragment is available
488 * if so:
489 * (1) copy over the fragment to s->internal->init_buf->data[]
490 * (2) update s->internal->init_num
491 */
492 pitem *item;
493 hm_fragment *frag;
494 int al;
495
496 *ok = 0;
497 item = pqueue_peek(s->d1->buffered_messages);
498 if (item == NULL)
499 return 0;
500
501 frag = (hm_fragment *)item->data;
502
503 /* Don't return if reassembly still in progress */
504 if (frag->reassembly != NULL)
505 return 0;
506
507 if (s->d1->handshake_read_seq == frag->msg_header.seq) {
508 unsigned long frag_len = frag->msg_header.frag_len;
509 pqueue_pop(s->d1->buffered_messages);
510
511 al = dtls1_preprocess_fragment(s, &frag->msg_header, max);
512
513 if (al == 0) /* no alert */
514 {
515 unsigned char *p = (unsigned char *)s->internal->init_buf->data + DTLS1_HM_HEADER_LENGTH;
516 memcpy(&p[frag->msg_header.frag_off],
517 frag->fragment, frag->msg_header.frag_len);
518 }
519
520 dtls1_hm_fragment_free(frag);
521 pitem_free(item);
522
523 if (al == 0) {
524 *ok = 1;
525 return frag_len;
526 }
527
528 ssl3_send_alert(s, SSL3_AL_FATAL, al);
529 s->internal->init_num = 0;
530 *ok = 0;
531 return -1;
532 } else
533 return 0;
534 }
535
536 /*
537 * dtls1_max_handshake_message_len returns the maximum number of bytes
538 * permitted in a DTLS handshake message for |s|. The minimum is 16KB,
539 * but may be greater if the maximum certificate list size requires it.
540 */
541 static unsigned long
dtls1_max_handshake_message_len(const SSL * s)542 dtls1_max_handshake_message_len(const SSL *s)
543 {
544 unsigned long max_len;
545
546 max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
547 if (max_len < (unsigned long)s->internal->max_cert_list)
548 return s->internal->max_cert_list;
549 return max_len;
550 }
551
552 static int
dtls1_reassemble_fragment(SSL * s,struct hm_header_st * msg_hdr,int * ok)553 dtls1_reassemble_fragment(SSL *s, struct hm_header_st* msg_hdr, int *ok)
554 {
555 hm_fragment *frag = NULL;
556 pitem *item = NULL;
557 int i = -1, is_complete;
558 unsigned char seq64be[8];
559 unsigned long frag_len = msg_hdr->frag_len;
560
561 if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len ||
562 msg_hdr->msg_len > dtls1_max_handshake_message_len(s))
563 goto err;
564
565 if (frag_len == 0) {
566 i = DTLS1_HM_FRAGMENT_RETRY;
567 goto err;
568 }
569
570 /* Try to find item in queue */
571 memset(seq64be, 0, sizeof(seq64be));
572 seq64be[6] = (unsigned char)(msg_hdr->seq >> 8);
573 seq64be[7] = (unsigned char)msg_hdr->seq;
574 item = pqueue_find(s->d1->buffered_messages, seq64be);
575
576 if (item == NULL) {
577 frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1);
578 if (frag == NULL)
579 goto err;
580 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
581 frag->msg_header.frag_len = frag->msg_header.msg_len;
582 frag->msg_header.frag_off = 0;
583 } else {
584 frag = (hm_fragment*)item->data;
585 if (frag->msg_header.msg_len != msg_hdr->msg_len) {
586 item = NULL;
587 frag = NULL;
588 goto err;
589 }
590 }
591
592 /*
593 * If message is already reassembled, this must be a
594 * retransmit and can be dropped.
595 */
596 if (frag->reassembly == NULL) {
597 unsigned char devnull [256];
598
599 while (frag_len) {
600 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
601 devnull, frag_len > sizeof(devnull) ?
602 sizeof(devnull) : frag_len, 0);
603 if (i <= 0)
604 goto err;
605 frag_len -= i;
606 }
607 i = DTLS1_HM_FRAGMENT_RETRY;
608 goto err;
609 }
610
611 /* read the body of the fragment (header has already been read */
612 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
613 frag->fragment + msg_hdr->frag_off, frag_len, 0);
614 if (i <= 0 || (unsigned long)i != frag_len)
615 goto err;
616
617 RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off,
618 (long)(msg_hdr->frag_off + frag_len));
619
620 RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len,
621 is_complete);
622
623 if (is_complete) {
624 free(frag->reassembly);
625 frag->reassembly = NULL;
626 }
627
628 if (item == NULL) {
629 memset(seq64be, 0, sizeof(seq64be));
630 seq64be[6] = (unsigned char)(msg_hdr->seq >> 8);
631 seq64be[7] = (unsigned char)(msg_hdr->seq);
632
633 item = pitem_new(seq64be, frag);
634 if (item == NULL) {
635 i = -1;
636 goto err;
637 }
638
639 pqueue_insert(s->d1->buffered_messages, item);
640 }
641
642 return DTLS1_HM_FRAGMENT_RETRY;
643
644 err:
645 if (item == NULL && frag != NULL)
646 dtls1_hm_fragment_free(frag);
647 *ok = 0;
648 return i;
649 }
650
651
652 static int
dtls1_process_out_of_seq_message(SSL * s,struct hm_header_st * msg_hdr,int * ok)653 dtls1_process_out_of_seq_message(SSL *s, struct hm_header_st* msg_hdr, int *ok)
654 {
655 int i = -1;
656 hm_fragment *frag = NULL;
657 pitem *item = NULL;
658 unsigned char seq64be[8];
659 unsigned long frag_len = msg_hdr->frag_len;
660
661 if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len)
662 goto err;
663
664 /* Try to find item in queue, to prevent duplicate entries */
665 memset(seq64be, 0, sizeof(seq64be));
666 seq64be[6] = (unsigned char) (msg_hdr->seq >> 8);
667 seq64be[7] = (unsigned char) msg_hdr->seq;
668 item = pqueue_find(s->d1->buffered_messages, seq64be);
669
670 /*
671 * If we already have an entry and this one is a fragment,
672 * don't discard it and rather try to reassemble it.
673 */
674 if (item != NULL && frag_len < msg_hdr->msg_len)
675 item = NULL;
676
677 /*
678 * Discard the message if sequence number was already there, is
679 * too far in the future, already in the queue or if we received
680 * a FINISHED before the SERVER_HELLO, which then must be a stale
681 * retransmit.
682 */
683 if (msg_hdr->seq <= s->d1->handshake_read_seq ||
684 msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL ||
685 (s->d1->handshake_read_seq == 0 &&
686 msg_hdr->type == SSL3_MT_FINISHED)) {
687 unsigned char devnull [256];
688
689 while (frag_len) {
690 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
691 devnull, frag_len > sizeof(devnull) ?
692 sizeof(devnull) : frag_len, 0);
693 if (i <= 0)
694 goto err;
695 frag_len -= i;
696 }
697 } else {
698 if (frag_len < msg_hdr->msg_len)
699 return dtls1_reassemble_fragment(s, msg_hdr, ok);
700
701 if (frag_len > dtls1_max_handshake_message_len(s))
702 goto err;
703
704 frag = dtls1_hm_fragment_new(frag_len, 0);
705 if (frag == NULL)
706 goto err;
707
708 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
709
710 if (frag_len) {
711 /* read the body of the fragment (header has already been read */
712 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
713 frag->fragment, frag_len, 0);
714 if (i <= 0 || (unsigned long)i != frag_len)
715 goto err;
716 }
717
718 memset(seq64be, 0, sizeof(seq64be));
719 seq64be[6] = (unsigned char)(msg_hdr->seq >> 8);
720 seq64be[7] = (unsigned char)(msg_hdr->seq);
721
722 item = pitem_new(seq64be, frag);
723 if (item == NULL)
724 goto err;
725
726 pqueue_insert(s->d1->buffered_messages, item);
727 }
728
729 return DTLS1_HM_FRAGMENT_RETRY;
730
731 err:
732 if (item == NULL && frag != NULL)
733 dtls1_hm_fragment_free(frag);
734 *ok = 0;
735 return i;
736 }
737
738
739 static long
dtls1_get_message_fragment(SSL * s,int st1,int stn,long max,int * ok)740 dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
741 {
742 unsigned char wire[DTLS1_HM_HEADER_LENGTH];
743 unsigned long len, frag_off, frag_len;
744 struct hm_header_st msg_hdr;
745 int i, al;
746 CBS cbs;
747
748 again:
749 /* see if we have the required fragment already */
750 if ((frag_len = dtls1_retrieve_buffered_fragment(s, max, ok)) || *ok) {
751 if (*ok)
752 s->internal->init_num = frag_len;
753 return frag_len;
754 }
755
756 /* read handshake message header */
757 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, wire,
758 DTLS1_HM_HEADER_LENGTH, 0);
759 if (i <= 0) {
760 /* nbio, or an error */
761 s->internal->rwstate = SSL_READING;
762 *ok = 0;
763 return i;
764 }
765
766 CBS_init(&cbs, wire, i);
767 if (!dtls1_get_message_header(&cbs, &msg_hdr)) {
768 /* Handshake fails if message header is incomplete. */
769 al = SSL_AD_UNEXPECTED_MESSAGE;
770 SSLerror(s, SSL_R_UNEXPECTED_MESSAGE);
771 goto fatal_err;
772 }
773
774 /*
775 * if this is a future (or stale) message it gets buffered
776 * (or dropped)--no further processing at this time
777 * While listening, we accept seq 1 (ClientHello with cookie)
778 * although we're still expecting seq 0 (ClientHello)
779 */
780 if (msg_hdr.seq != s->d1->handshake_read_seq &&
781 !(s->d1->listen && msg_hdr.seq == 1))
782 return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
783
784 len = msg_hdr.msg_len;
785 frag_off = msg_hdr.frag_off;
786 frag_len = msg_hdr.frag_len;
787
788 if (frag_len && frag_len < len)
789 return dtls1_reassemble_fragment(s, &msg_hdr, ok);
790
791 if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
792 wire[0] == SSL3_MT_HELLO_REQUEST) {
793 /*
794 * The server may always send 'Hello Request' messages --
795 * we are doing a handshake anyway now, so ignore them
796 * if their format is correct. Does not count for
797 * 'Finished' MAC.
798 */
799 if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0) {
800 if (s->internal->msg_callback)
801 s->internal->msg_callback(0, s->version,
802 SSL3_RT_HANDSHAKE, wire,
803 DTLS1_HM_HEADER_LENGTH, s,
804 s->internal->msg_callback_arg);
805
806 s->internal->init_num = 0;
807 goto again;
808 }
809 else /* Incorrectly formated Hello request */
810 {
811 al = SSL_AD_UNEXPECTED_MESSAGE;
812 SSLerror(s, SSL_R_UNEXPECTED_MESSAGE);
813 goto fatal_err;
814 }
815 }
816
817 if ((al = dtls1_preprocess_fragment(s, &msg_hdr, max)))
818 goto fatal_err;
819
820 /* XDTLS: ressurect this when restart is in place */
821 s->s3->hs.state = stn;
822
823 if (frag_len > 0) {
824 unsigned char *p = (unsigned char *)s->internal->init_buf->data + DTLS1_HM_HEADER_LENGTH;
825
826 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
827 &p[frag_off], frag_len, 0);
828 /* XDTLS: fix this--message fragments cannot span multiple packets */
829 if (i <= 0) {
830 s->internal->rwstate = SSL_READING;
831 *ok = 0;
832 return i;
833 }
834 } else
835 i = 0;
836
837 /*
838 * XDTLS: an incorrectly formatted fragment should cause the
839 * handshake to fail
840 */
841 if (i != (int)frag_len) {
842 al = SSL_AD_ILLEGAL_PARAMETER;
843 SSLerror(s, SSL_R_SSLV3_ALERT_ILLEGAL_PARAMETER);
844 goto fatal_err;
845 }
846
847 /*
848 * Note that s->internal->init_num is *not* used as current offset in
849 * s->internal->init_buf->data, but as a counter summing up fragments'
850 * lengths: as soon as they sum up to handshake packet
851 * length, we assume we have got all the fragments.
852 */
853 s->internal->init_num = frag_len;
854 *ok = 1;
855 return frag_len;
856
857 fatal_err:
858 ssl3_send_alert(s, SSL3_AL_FATAL, al);
859 s->internal->init_num = 0;
860
861 *ok = 0;
862 return (-1);
863 }
864
865 int
dtls1_read_failed(SSL * s,int code)866 dtls1_read_failed(SSL *s, int code)
867 {
868 if (code > 0) {
869 #ifdef DEBUG
870 fprintf(stderr, "invalid state reached %s:%d",
871 __FILE__, __LINE__);
872 #endif
873 return 1;
874 }
875
876 if (!dtls1_is_timer_expired(s)) {
877 /*
878 * not a timeout, none of our business, let higher layers
879 * handle this. in fact it's probably an error
880 */
881 return code;
882 }
883
884 if (!SSL_in_init(s)) /* done, no need to send a retransmit */
885 {
886 BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
887 return code;
888 }
889
890 return dtls1_handle_timeout(s);
891 }
892
893 int
dtls1_get_queue_priority(unsigned short seq,int is_ccs)894 dtls1_get_queue_priority(unsigned short seq, int is_ccs)
895 {
896 /*
897 * The index of the retransmission queue actually is the message
898 * sequence number, since the queue only contains messages of a
899 * single handshake. However, the ChangeCipherSpec has no message
900 * sequence number and so using only the sequence will result in
901 * the CCS and Finished having the same index. To prevent this, the
902 * sequence number is multiplied by 2. In case of a CCS 1 is
903 * subtracted. This does not only differ CSS and Finished, it also
904 * maintains the order of the index (important for priority queues)
905 * and fits in the unsigned short variable.
906 */
907 return seq * 2 - is_ccs;
908 }
909
910 int
dtls1_retransmit_buffered_messages(SSL * s)911 dtls1_retransmit_buffered_messages(SSL *s)
912 {
913 pqueue sent = s->d1->sent_messages;
914 piterator iter;
915 pitem *item;
916 hm_fragment *frag;
917 int found = 0;
918
919 iter = pqueue_iterator(sent);
920
921 for (item = pqueue_next(&iter); item != NULL;
922 item = pqueue_next(&iter)) {
923 frag = (hm_fragment *)item->data;
924 if (dtls1_retransmit_message(s,
925 (unsigned short)dtls1_get_queue_priority(
926 frag->msg_header.seq, frag->msg_header.is_ccs), 0,
927 &found) <= 0 && found) {
928 #ifdef DEBUG
929 fprintf(stderr, "dtls1_retransmit_message() failed\n");
930 #endif
931 return -1;
932 }
933 }
934
935 return 1;
936 }
937
938 int
dtls1_buffer_message(SSL * s,int is_ccs)939 dtls1_buffer_message(SSL *s, int is_ccs)
940 {
941 pitem *item;
942 hm_fragment *frag;
943 unsigned char seq64be[8];
944
945 /* Buffer the messsage in order to handle DTLS retransmissions. */
946
947 /*
948 * This function is called immediately after a message has
949 * been serialized
950 */
951 OPENSSL_assert(s->internal->init_off == 0);
952
953 frag = dtls1_hm_fragment_new(s->internal->init_num, 0);
954 if (frag == NULL)
955 return 0;
956
957 memcpy(frag->fragment, s->internal->init_buf->data, s->internal->init_num);
958
959 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
960 (is_ccs ? DTLS1_CCS_HEADER_LENGTH : DTLS1_HM_HEADER_LENGTH) ==
961 (unsigned int)s->internal->init_num);
962
963 frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
964 frag->msg_header.seq = s->d1->w_msg_hdr.seq;
965 frag->msg_header.type = s->d1->w_msg_hdr.type;
966 frag->msg_header.frag_off = 0;
967 frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
968 frag->msg_header.is_ccs = is_ccs;
969
970 /* save current state*/
971 frag->msg_header.saved_retransmit_state.session = s->session;
972 frag->msg_header.saved_retransmit_state.epoch =
973 tls12_record_layer_write_epoch(s->internal->rl);
974
975 memset(seq64be, 0, sizeof(seq64be));
976 seq64be[6] = (unsigned char)(dtls1_get_queue_priority(
977 frag->msg_header.seq, frag->msg_header.is_ccs) >> 8);
978 seq64be[7] = (unsigned char)(dtls1_get_queue_priority(
979 frag->msg_header.seq, frag->msg_header.is_ccs));
980
981 item = pitem_new(seq64be, frag);
982 if (item == NULL) {
983 dtls1_hm_fragment_free(frag);
984 return 0;
985 }
986
987 pqueue_insert(s->d1->sent_messages, item);
988 return 1;
989 }
990
991 int
dtls1_retransmit_message(SSL * s,unsigned short seq,unsigned long frag_off,int * found)992 dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
993 int *found)
994 {
995 int ret;
996 /* XDTLS: for now assuming that read/writes are blocking */
997 pitem *item;
998 hm_fragment *frag;
999 unsigned long header_length;
1000 unsigned char seq64be[8];
1001 struct dtls1_retransmit_state saved_state;
1002
1003 /*
1004 OPENSSL_assert(s->internal->init_num == 0);
1005 OPENSSL_assert(s->internal->init_off == 0);
1006 */
1007
1008 /* XDTLS: the requested message ought to be found, otherwise error */
1009 memset(seq64be, 0, sizeof(seq64be));
1010 seq64be[6] = (unsigned char)(seq >> 8);
1011 seq64be[7] = (unsigned char)seq;
1012
1013 item = pqueue_find(s->d1->sent_messages, seq64be);
1014 if (item == NULL) {
1015 #ifdef DEBUG
1016 fprintf(stderr, "retransmit: message %d non-existent\n", seq);
1017 #endif
1018 *found = 0;
1019 return 0;
1020 }
1021
1022 *found = 1;
1023 frag = (hm_fragment *)item->data;
1024
1025 if (frag->msg_header.is_ccs)
1026 header_length = DTLS1_CCS_HEADER_LENGTH;
1027 else
1028 header_length = DTLS1_HM_HEADER_LENGTH;
1029
1030 memcpy(s->internal->init_buf->data, frag->fragment,
1031 frag->msg_header.msg_len + header_length);
1032 s->internal->init_num = frag->msg_header.msg_len + header_length;
1033
1034 dtls1_set_message_header_int(s, frag->msg_header.type,
1035 frag->msg_header.msg_len, frag->msg_header.seq, 0,
1036 frag->msg_header.frag_len);
1037
1038 /* save current state */
1039 saved_state.session = s->session;
1040 saved_state.epoch = tls12_record_layer_write_epoch(s->internal->rl);
1041
1042 s->d1->retransmitting = 1;
1043
1044 /* restore state in which the message was originally sent */
1045 s->session = frag->msg_header.saved_retransmit_state.session;
1046 if (!tls12_record_layer_use_write_epoch(s->internal->rl,
1047 frag->msg_header.saved_retransmit_state.epoch))
1048 return 0;
1049
1050 ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1051 SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1052
1053 /* restore current state */
1054 s->session = saved_state.session;
1055 if (!tls12_record_layer_use_write_epoch(s->internal->rl,
1056 saved_state.epoch))
1057 return 0;
1058
1059 s->d1->retransmitting = 0;
1060
1061 (void)BIO_flush(SSL_get_wbio(s));
1062 return ret;
1063 }
1064
1065 /* call this function when the buffered messages are no longer needed */
1066 void
dtls1_clear_record_buffer(SSL * s)1067 dtls1_clear_record_buffer(SSL *s)
1068 {
1069 hm_fragment *frag;
1070 pitem *item;
1071
1072 for(item = pqueue_pop(s->d1->sent_messages); item != NULL;
1073 item = pqueue_pop(s->d1->sent_messages)) {
1074 frag = item->data;
1075 if (frag->msg_header.is_ccs)
1076 tls12_record_layer_write_epoch_done(s->internal->rl,
1077 frag->msg_header.saved_retransmit_state.epoch);
1078 dtls1_hm_fragment_free(frag);
1079 pitem_free(item);
1080 }
1081 }
1082
1083 void
dtls1_set_message_header(SSL * s,unsigned char mt,unsigned long len,unsigned long frag_off,unsigned long frag_len)1084 dtls1_set_message_header(SSL *s, unsigned char mt, unsigned long len,
1085 unsigned long frag_off, unsigned long frag_len)
1086 {
1087 /* Don't change sequence numbers while listening */
1088 if (frag_off == 0 && !s->d1->listen) {
1089 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1090 s->d1->next_handshake_write_seq++;
1091 }
1092
1093 dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1094 frag_off, frag_len);
1095 }
1096
1097 /* don't actually do the writing, wait till the MTU has been retrieved */
1098 void
dtls1_set_message_header_int(SSL * s,unsigned char mt,unsigned long len,unsigned short seq_num,unsigned long frag_off,unsigned long frag_len)1099 dtls1_set_message_header_int(SSL *s, unsigned char mt, unsigned long len,
1100 unsigned short seq_num, unsigned long frag_off, unsigned long frag_len)
1101 {
1102 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1103
1104 msg_hdr->type = mt;
1105 msg_hdr->msg_len = len;
1106 msg_hdr->seq = seq_num;
1107 msg_hdr->frag_off = frag_off;
1108 msg_hdr->frag_len = frag_len;
1109 }
1110
1111 static void
dtls1_fix_message_header(SSL * s,unsigned long frag_off,unsigned long frag_len)1112 dtls1_fix_message_header(SSL *s, unsigned long frag_off, unsigned long frag_len)
1113 {
1114 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1115
1116 msg_hdr->frag_off = frag_off;
1117 msg_hdr->frag_len = frag_len;
1118 }
1119
1120 static int
dtls1_write_message_header(const struct hm_header_st * msg_hdr,unsigned long frag_off,unsigned long frag_len,unsigned char * p)1121 dtls1_write_message_header(const struct hm_header_st *msg_hdr,
1122 unsigned long frag_off, unsigned long frag_len, unsigned char *p)
1123 {
1124 CBB cbb;
1125
1126 /* We assume DTLS1_HM_HEADER_LENGTH bytes are available for now... */
1127 if (!CBB_init_fixed(&cbb, p, DTLS1_HM_HEADER_LENGTH))
1128 return 0;
1129 if (!CBB_add_u8(&cbb, msg_hdr->type))
1130 goto err;
1131 if (!CBB_add_u24(&cbb, msg_hdr->msg_len))
1132 goto err;
1133 if (!CBB_add_u16(&cbb, msg_hdr->seq))
1134 goto err;
1135 if (!CBB_add_u24(&cbb, frag_off))
1136 goto err;
1137 if (!CBB_add_u24(&cbb, frag_len))
1138 goto err;
1139 if (!CBB_finish(&cbb, NULL, NULL))
1140 goto err;
1141
1142 return 1;
1143
1144 err:
1145 CBB_cleanup(&cbb);
1146 return 0;
1147 }
1148
1149 unsigned int
dtls1_min_mtu(void)1150 dtls1_min_mtu(void)
1151 {
1152 return (g_probable_mtu[(sizeof(g_probable_mtu) /
1153 sizeof(g_probable_mtu[0])) - 1]);
1154 }
1155
1156 static unsigned int
dtls1_guess_mtu(unsigned int curr_mtu)1157 dtls1_guess_mtu(unsigned int curr_mtu)
1158 {
1159 unsigned int i;
1160
1161 if (curr_mtu == 0)
1162 return g_probable_mtu[0];
1163
1164 for (i = 0; i < sizeof(g_probable_mtu) / sizeof(g_probable_mtu[0]); i++)
1165 if (curr_mtu > g_probable_mtu[i])
1166 return g_probable_mtu[i];
1167
1168 return curr_mtu;
1169 }
1170
1171 int
dtls1_get_message_header(CBS * header,struct hm_header_st * msg_hdr)1172 dtls1_get_message_header(CBS *header, struct hm_header_st *msg_hdr)
1173 {
1174 uint32_t msg_len, frag_off, frag_len;
1175 uint16_t seq;
1176 uint8_t type;
1177
1178 memset(msg_hdr, 0, sizeof(*msg_hdr));
1179
1180 if (!CBS_get_u8(header, &type))
1181 return 0;
1182 if (!CBS_get_u24(header, &msg_len))
1183 return 0;
1184 if (!CBS_get_u16(header, &seq))
1185 return 0;
1186 if (!CBS_get_u24(header, &frag_off))
1187 return 0;
1188 if (!CBS_get_u24(header, &frag_len))
1189 return 0;
1190
1191 msg_hdr->type = type;
1192 msg_hdr->msg_len = msg_len;
1193 msg_hdr->seq = seq;
1194 msg_hdr->frag_off = frag_off;
1195 msg_hdr->frag_len = frag_len;
1196
1197 return 1;
1198 }
1199