1 /* $OpenBSD: d1_pkt.c,v 1.123 2022/03/26 15:05:53 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 <endian.h>
117 #include <errno.h>
118 #include <stdio.h>
119
120 #include <openssl/buffer.h>
121 #include <openssl/evp.h>
122
123 #include "bytestring.h"
124 #include "dtls_locl.h"
125 #include "pqueue.h"
126 #include "ssl_locl.h"
127
128 /* mod 128 saturating subtract of two 64-bit values in big-endian order */
129 static int
satsub64be(const unsigned char * v1,const unsigned char * v2)130 satsub64be(const unsigned char *v1, const unsigned char *v2)
131 {
132 int ret, sat, brw, i;
133
134 if (sizeof(long) == 8)
135 do {
136 long l;
137
138 if (BYTE_ORDER == LITTLE_ENDIAN)
139 break;
140 /* not reached on little-endians */
141 /* following test is redundant, because input is
142 * always aligned, but I take no chances... */
143 if (((size_t)v1 | (size_t)v2) & 0x7)
144 break;
145
146 l = *((long *)v1);
147 l -= *((long *)v2);
148 if (l > 128)
149 return 128;
150 else if (l<-128)
151 return -128;
152 else
153 return (int)l;
154 } while (0);
155
156 ret = (int)v1[7] - (int)v2[7];
157 sat = 0;
158 brw = ret >> 8; /* brw is either 0 or -1 */
159 if (ret & 0x80) {
160 for (i = 6; i >= 0; i--) {
161 brw += (int)v1[i]-(int)v2[i];
162 sat |= ~brw;
163 brw >>= 8;
164 }
165 } else {
166 for (i = 6; i >= 0; i--) {
167 brw += (int)v1[i]-(int)v2[i];
168 sat |= brw;
169 brw >>= 8;
170 }
171 }
172 brw <<= 8; /* brw is either 0 or -256 */
173
174 if (sat & 0xff)
175 return brw | 0x80;
176 else
177 return brw + (ret & 0xFF);
178 }
179
180 static int dtls1_record_replay_check(SSL *s, DTLS1_BITMAP *bitmap,
181 const unsigned char *seq);
182 static void dtls1_record_bitmap_update(SSL *s, DTLS1_BITMAP *bitmap,
183 const unsigned char *seq);
184 static DTLS1_BITMAP *dtls1_get_bitmap(SSL *s, SSL3_RECORD_INTERNAL *rr,
185 unsigned int *is_next_epoch);
186 static int dtls1_buffer_record(SSL *s, record_pqueue *q,
187 unsigned char *priority);
188 static int dtls1_process_record(SSL *s);
189
190 /* copy buffered record into SSL structure */
191 static int
dtls1_copy_record(SSL * s,DTLS1_RECORD_DATA_INTERNAL * rdata)192 dtls1_copy_record(SSL *s, DTLS1_RECORD_DATA_INTERNAL *rdata)
193 {
194 ssl3_release_buffer(&s->s3->rbuf);
195
196 s->internal->packet = rdata->packet;
197 s->internal->packet_length = rdata->packet_length;
198 memcpy(&(s->s3->rbuf), &(rdata->rbuf), sizeof(SSL3_BUFFER_INTERNAL));
199 memcpy(&(s->s3->rrec), &(rdata->rrec), sizeof(SSL3_RECORD_INTERNAL));
200
201 return (1);
202 }
203
204 static int
dtls1_buffer_record(SSL * s,record_pqueue * queue,unsigned char * priority)205 dtls1_buffer_record(SSL *s, record_pqueue *queue, unsigned char *priority)
206 {
207 DTLS1_RECORD_DATA_INTERNAL *rdata;
208 pitem *item;
209
210 /* Limit the size of the queue to prevent DOS attacks */
211 if (pqueue_size(queue->q) >= 100)
212 return 0;
213
214 rdata = malloc(sizeof(DTLS1_RECORD_DATA_INTERNAL));
215 item = pitem_new(priority, rdata);
216 if (rdata == NULL || item == NULL)
217 goto init_err;
218
219 rdata->packet = s->internal->packet;
220 rdata->packet_length = s->internal->packet_length;
221 memcpy(&(rdata->rbuf), &(s->s3->rbuf), sizeof(SSL3_BUFFER_INTERNAL));
222 memcpy(&(rdata->rrec), &(s->s3->rrec), sizeof(SSL3_RECORD_INTERNAL));
223
224 item->data = rdata;
225
226 s->internal->packet = NULL;
227 s->internal->packet_length = 0;
228 memset(&(s->s3->rbuf), 0, sizeof(SSL3_BUFFER_INTERNAL));
229 memset(&(s->s3->rrec), 0, sizeof(SSL3_RECORD_INTERNAL));
230
231 if (!ssl3_setup_buffers(s))
232 goto err;
233
234 /* insert should not fail, since duplicates are dropped */
235 if (pqueue_insert(queue->q, item) == NULL)
236 goto err;
237
238 return (1);
239
240 err:
241 ssl3_release_buffer(&rdata->rbuf);
242
243 init_err:
244 SSLerror(s, ERR_R_INTERNAL_ERROR);
245 free(rdata);
246 pitem_free(item);
247 return (-1);
248 }
249
250
251 static int
dtls1_retrieve_buffered_record(SSL * s,record_pqueue * queue)252 dtls1_retrieve_buffered_record(SSL *s, record_pqueue *queue)
253 {
254 pitem *item;
255
256 item = pqueue_pop(queue->q);
257 if (item) {
258 dtls1_copy_record(s, item->data);
259
260 free(item->data);
261 pitem_free(item);
262
263 return (1);
264 }
265
266 return (0);
267 }
268
269 static int
dtls1_process_buffered_record(SSL * s)270 dtls1_process_buffered_record(SSL *s)
271 {
272 /* Check if epoch is current. */
273 if (s->d1->unprocessed_rcds.epoch !=
274 tls12_record_layer_read_epoch(s->internal->rl))
275 return (0);
276
277 /* Update epoch once all unprocessed records have been processed. */
278 if (pqueue_peek(s->d1->unprocessed_rcds.q) == NULL) {
279 s->d1->unprocessed_rcds.epoch =
280 tls12_record_layer_read_epoch(s->internal->rl) + 1;
281 return (0);
282 }
283
284 /* Process one of the records. */
285 if (!dtls1_retrieve_buffered_record(s, &s->d1->unprocessed_rcds))
286 return (-1);
287 if (!dtls1_process_record(s))
288 return (-1);
289
290 return (1);
291 }
292
293 static int
dtls1_process_record(SSL * s)294 dtls1_process_record(SSL *s)
295 {
296 SSL3_RECORD_INTERNAL *rr = &(s->s3->rrec);
297 uint8_t alert_desc;
298 uint8_t *out;
299 size_t out_len;
300
301 tls12_record_layer_set_version(s->internal->rl, s->version);
302
303 if (!tls12_record_layer_open_record(s->internal->rl, s->internal->packet,
304 s->internal->packet_length, &out, &out_len)) {
305 tls12_record_layer_alert(s->internal->rl, &alert_desc);
306
307 if (alert_desc == 0)
308 goto err;
309
310 /*
311 * DTLS should silently discard invalid records, including those
312 * with a bad MAC, as per RFC 6347 section 4.1.2.1.
313 */
314 if (alert_desc == SSL_AD_BAD_RECORD_MAC) {
315 out_len = 0;
316 goto done;
317 }
318
319 if (alert_desc == SSL_AD_RECORD_OVERFLOW)
320 SSLerror(s, SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
321
322 goto fatal_err;
323 }
324
325 done:
326 rr->data = out;
327 rr->length = out_len;
328 rr->off = 0;
329
330 s->internal->packet_length = 0;
331
332 return (1);
333
334 fatal_err:
335 ssl3_send_alert(s, SSL3_AL_FATAL, alert_desc);
336 err:
337 return (0);
338 }
339
340 /* Call this to get a new input record.
341 * It will return <= 0 if more data is needed, normally due to an error
342 * or non-blocking IO.
343 * When it finishes, one packet has been decoded and can be found in
344 * ssl->s3->internal->rrec.type - is the type of record
345 * ssl->s3->internal->rrec.data, - data
346 * ssl->s3->internal->rrec.length, - number of bytes
347 */
348 /* used only by dtls1_read_bytes */
349 int
dtls1_get_record(SSL * s)350 dtls1_get_record(SSL *s)
351 {
352 SSL3_RECORD_INTERNAL *rr = &(s->s3->rrec);
353 unsigned char *p = NULL;
354 DTLS1_BITMAP *bitmap;
355 unsigned int is_next_epoch;
356 int ret, n;
357
358 /* See if there are pending records that can now be processed. */
359 if ((ret = dtls1_process_buffered_record(s)) != 0)
360 return (ret);
361
362 /* get something from the wire */
363 if (0) {
364 again:
365 /* dump this record on all retries */
366 rr->length = 0;
367 s->internal->packet_length = 0;
368 }
369
370 /* check if we have the header */
371 if ((s->internal->rstate != SSL_ST_READ_BODY) ||
372 (s->internal->packet_length < DTLS1_RT_HEADER_LENGTH)) {
373 CBS header, seq_no;
374 uint16_t epoch, len, ssl_version;
375 uint8_t type;
376
377 n = ssl3_packet_read(s, DTLS1_RT_HEADER_LENGTH);
378 if (n <= 0)
379 return (n);
380
381 /* If this packet contained a partial record, dump it. */
382 if (n != DTLS1_RT_HEADER_LENGTH)
383 goto again;
384
385 s->internal->rstate = SSL_ST_READ_BODY;
386
387 CBS_init(&header, s->internal->packet, s->internal->packet_length);
388
389 /* Pull apart the header into the DTLS1_RECORD */
390 if (!CBS_get_u8(&header, &type))
391 goto again;
392 if (!CBS_get_u16(&header, &ssl_version))
393 goto again;
394
395 /* Sequence number is 64 bits, with top 2 bytes = epoch. */
396 if (!CBS_get_bytes(&header, &seq_no, SSL3_SEQUENCE_SIZE))
397 goto again;
398 if (!CBS_get_u16(&seq_no, &epoch))
399 goto again;
400 if (!CBS_write_bytes(&seq_no, &rr->seq_num[2],
401 sizeof(rr->seq_num) - 2, NULL))
402 goto again;
403
404 if (!CBS_get_u16(&header, &len))
405 goto again;
406
407 rr->type = type;
408 rr->epoch = epoch;
409 rr->length = len;
410
411 /* unexpected version, silently discard */
412 if (!s->internal->first_packet && ssl_version != s->version)
413 goto again;
414
415 /* wrong version, silently discard record */
416 if ((ssl_version & 0xff00) != (s->version & 0xff00))
417 goto again;
418
419 /* record too long, silently discard it */
420 if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH)
421 goto again;
422
423 /* now s->internal->rstate == SSL_ST_READ_BODY */
424 p = (unsigned char *)CBS_data(&header);
425 }
426
427 /* s->internal->rstate == SSL_ST_READ_BODY, get and decode the data */
428
429 n = ssl3_packet_extend(s, DTLS1_RT_HEADER_LENGTH + rr->length);
430 if (n <= 0)
431 return (n);
432
433 /* If this packet contained a partial record, dump it. */
434 if (n != DTLS1_RT_HEADER_LENGTH + rr->length)
435 goto again;
436
437 s->internal->rstate = SSL_ST_READ_HEADER; /* set state for later operations */
438
439 /* match epochs. NULL means the packet is dropped on the floor */
440 bitmap = dtls1_get_bitmap(s, rr, &is_next_epoch);
441 if (bitmap == NULL)
442 goto again;
443
444 /*
445 * Check whether this is a repeat, or aged record.
446 * Don't check if we're listening and this message is
447 * a ClientHello. They can look as if they're replayed,
448 * since they arrive from different connections and
449 * would be dropped unnecessarily.
450 */
451 if (!(s->d1->listen && rr->type == SSL3_RT_HANDSHAKE &&
452 p != NULL && *p == SSL3_MT_CLIENT_HELLO) &&
453 !dtls1_record_replay_check(s, bitmap, rr->seq_num))
454 goto again;
455
456 /* just read a 0 length packet */
457 if (rr->length == 0)
458 goto again;
459
460 /* If this record is from the next epoch (either HM or ALERT),
461 * and a handshake is currently in progress, buffer it since it
462 * cannot be processed at this time. However, do not buffer
463 * anything while listening.
464 */
465 if (is_next_epoch) {
466 if ((SSL_in_init(s) || s->internal->in_handshake) && !s->d1->listen) {
467 if (dtls1_buffer_record(s, &(s->d1->unprocessed_rcds),
468 rr->seq_num) < 0)
469 return (-1);
470 /* Mark receipt of record. */
471 dtls1_record_bitmap_update(s, bitmap, rr->seq_num);
472 }
473 goto again;
474 }
475
476 if (!dtls1_process_record(s))
477 goto again;
478
479 /* Mark receipt of record. */
480 dtls1_record_bitmap_update(s, bitmap, rr->seq_num);
481
482 return (1);
483 }
484
485 static int
dtls1_read_handshake_unexpected(SSL * s)486 dtls1_read_handshake_unexpected(SSL *s)
487 {
488 SSL3_RECORD_INTERNAL *rr = &s->s3->rrec;
489 struct hm_header_st hs_msg_hdr;
490 CBS cbs;
491 int ret;
492
493 if (s->internal->in_handshake) {
494 SSLerror(s, ERR_R_INTERNAL_ERROR);
495 return -1;
496 }
497
498 if (rr->off != 0) {
499 SSLerror(s, ERR_R_INTERNAL_ERROR);
500 return -1;
501 }
502
503 /* Parse handshake message header. */
504 CBS_init(&cbs, rr->data, rr->length);
505 if (!dtls1_get_message_header(&cbs, &hs_msg_hdr))
506 return -1; /* XXX - probably should drop/continue. */
507
508 /* This may just be a stale retransmit. */
509 if (rr->epoch != tls12_record_layer_read_epoch(s->internal->rl)) {
510 rr->length = 0;
511 return 1;
512 }
513
514 if (hs_msg_hdr.type == SSL3_MT_HELLO_REQUEST) {
515 /*
516 * Incoming HelloRequest messages should only be received by a
517 * client. A server may send these at any time - a client should
518 * ignore the message if received in the middle of a handshake.
519 * See RFC 5246 sections 7.4 and 7.4.1.1.
520 */
521 if (s->server) {
522 SSLerror(s, SSL_R_UNEXPECTED_MESSAGE);
523 ssl3_send_alert(s, SSL3_AL_FATAL,
524 SSL_AD_UNEXPECTED_MESSAGE);
525 return -1;
526 }
527
528 /* XXX - should also check frag offset/length. */
529 if (hs_msg_hdr.msg_len != 0) {
530 SSLerror(s, SSL_R_BAD_HELLO_REQUEST);
531 ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
532 return -1;
533 }
534
535 ssl_msg_callback(s, 0, SSL3_RT_HANDSHAKE, rr->data,
536 DTLS1_HM_HEADER_LENGTH);
537
538 rr->length = 0;
539
540 /*
541 * It should be impossible to hit this, but keep the safety
542 * harness for now...
543 */
544 if (s->session == NULL || s->session->cipher == NULL)
545 return 1;
546
547 /*
548 * Ignore this message if we're currently handshaking,
549 * renegotiation is already pending or renegotiation is disabled
550 * via flags.
551 */
552 if (!SSL_is_init_finished(s) || s->s3->renegotiate ||
553 (s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS) != 0)
554 return 1;
555
556 s->d1->handshake_read_seq++;
557
558 /* XXX - why is this set here but not in ssl3? */
559 s->internal->new_session = 1;
560
561 if (!ssl3_renegotiate(s))
562 return 1;
563 if (!ssl3_renegotiate_check(s))
564 return 1;
565
566 } else if (hs_msg_hdr.type == SSL3_MT_CLIENT_HELLO) {
567 /*
568 * Incoming ClientHello messages should only be received by a
569 * server. A client may send these in response to server
570 * initiated renegotiation (HelloRequest) or in order to
571 * initiate renegotiation by the client. See RFC 5246 section
572 * 7.4.1.2.
573 */
574 if (!s->server) {
575 SSLerror(s, SSL_R_UNEXPECTED_MESSAGE);
576 ssl3_send_alert(s, SSL3_AL_FATAL,
577 SSL_AD_UNEXPECTED_MESSAGE);
578 return -1;
579 }
580
581 /*
582 * A client should not be sending a ClientHello unless we're not
583 * currently handshaking.
584 */
585 if (!SSL_is_init_finished(s)) {
586 SSLerror(s, SSL_R_UNEXPECTED_MESSAGE);
587 ssl3_send_alert(s, SSL3_AL_FATAL,
588 SSL_AD_UNEXPECTED_MESSAGE);
589 return -1;
590 }
591
592 if ((s->internal->options & SSL_OP_NO_CLIENT_RENEGOTIATION) != 0) {
593 ssl3_send_alert(s, SSL3_AL_FATAL,
594 SSL_AD_NO_RENEGOTIATION);
595 return -1;
596 }
597
598 if (s->session == NULL || s->session->cipher == NULL) {
599 SSLerror(s, ERR_R_INTERNAL_ERROR);
600 return -1;
601 }
602
603 /* Client requested renegotiation but it is not permitted. */
604 if (!s->s3->send_connection_binding ||
605 (s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS) != 0) {
606 ssl3_send_alert(s, SSL3_AL_WARNING,
607 SSL_AD_NO_RENEGOTIATION);
608 return 1;
609 }
610
611 s->s3->hs.state = SSL_ST_ACCEPT;
612 s->internal->renegotiate = 1;
613 s->internal->new_session = 1;
614
615 } else if (hs_msg_hdr.type == SSL3_MT_FINISHED && s->server) {
616 /*
617 * If we are server, we may have a repeated FINISHED of the
618 * client here, then retransmit our CCS and FINISHED.
619 */
620 if (dtls1_check_timeout_num(s) < 0)
621 return -1;
622
623 /* XXX - should this be calling ssl_msg_callback()? */
624
625 dtls1_retransmit_buffered_messages(s);
626
627 rr->length = 0;
628
629 return 1;
630
631 } else {
632 SSLerror(s, SSL_R_UNEXPECTED_MESSAGE);
633 ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
634 return -1;
635 }
636
637 if ((ret = s->internal->handshake_func(s)) < 0)
638 return ret;
639 if (ret == 0) {
640 SSLerror(s, SSL_R_SSL_HANDSHAKE_FAILURE);
641 return -1;
642 }
643
644 if (!(s->internal->mode & SSL_MODE_AUTO_RETRY)) {
645 if (s->s3->rbuf.left == 0) {
646 ssl_force_want_read(s);
647 return -1;
648 }
649 }
650
651 /*
652 * We either finished a handshake or ignored the request, now try again
653 * to obtain the (application) data we were asked for.
654 */
655 return 1;
656 }
657
658 /* Return up to 'len' payload bytes received in 'type' records.
659 * 'type' is one of the following:
660 *
661 * - SSL3_RT_HANDSHAKE (when ssl3_get_message calls us)
662 * - SSL3_RT_APPLICATION_DATA (when ssl3_read calls us)
663 * - 0 (during a shutdown, no data has to be returned)
664 *
665 * If we don't have stored data to work from, read a SSL/TLS record first
666 * (possibly multiple records if we still don't have anything to return).
667 *
668 * This function must handle any surprises the peer may have for us, such as
669 * Alert records (e.g. close_notify), ChangeCipherSpec records (not really
670 * a surprise, but handled as if it were), or renegotiation requests.
671 * Also if record payloads contain fragments too small to process, we store
672 * them until there is enough for the respective protocol (the record protocol
673 * may use arbitrary fragmentation and even interleaving):
674 * Change cipher spec protocol
675 * just 1 byte needed, no need for keeping anything stored
676 * Alert protocol
677 * 2 bytes needed (AlertLevel, AlertDescription)
678 * Handshake protocol
679 * 4 bytes needed (HandshakeType, uint24 length) -- we just have
680 * to detect unexpected Client Hello and Hello Request messages
681 * here, anything else is handled by higher layers
682 * Application data protocol
683 * none of our business
684 */
685 int
dtls1_read_bytes(SSL * s,int type,unsigned char * buf,int len,int peek)686 dtls1_read_bytes(SSL *s, int type, unsigned char *buf, int len, int peek)
687 {
688 SSL3_RECORD_INTERNAL *rr;
689 int rrcount = 0;
690 unsigned int n;
691 int ret;
692
693 if (s->s3->rbuf.buf == NULL) {
694 if (!ssl3_setup_buffers(s))
695 return -1;
696 }
697
698 if (len < 0) {
699 SSLerror(s, ERR_R_INTERNAL_ERROR);
700 return -1;
701 }
702
703 if (type != 0 && type != SSL3_RT_APPLICATION_DATA &&
704 type != SSL3_RT_HANDSHAKE) {
705 SSLerror(s, ERR_R_INTERNAL_ERROR);
706 return -1;
707 }
708 if (peek && type != SSL3_RT_APPLICATION_DATA) {
709 SSLerror(s, ERR_R_INTERNAL_ERROR);
710 return -1;
711 }
712
713 if (SSL_in_init(s) && !s->internal->in_handshake) {
714 if ((ret = s->internal->handshake_func(s)) < 0)
715 return ret;
716 if (ret == 0) {
717 SSLerror(s, SSL_R_SSL_HANDSHAKE_FAILURE);
718 return -1;
719 }
720 }
721
722 start:
723 /*
724 * Do not process more than three consecutive records, otherwise the
725 * peer can cause us to loop indefinitely. Instead, return with an
726 * SSL_ERROR_WANT_READ so the caller can choose when to handle further
727 * processing. In the future, the total number of non-handshake and
728 * non-application data records per connection should probably also be
729 * limited...
730 */
731 if (rrcount++ >= 3) {
732 ssl_force_want_read(s);
733 return -1;
734 }
735
736 s->internal->rwstate = SSL_NOTHING;
737
738 rr = &s->s3->rrec;
739
740 /*
741 * We are not handshaking and have no data yet, so process data buffered
742 * during the last handshake in advance, if any.
743 */
744 if (s->s3->hs.state == SSL_ST_OK && rr->length == 0)
745 dtls1_retrieve_buffered_record(s, &s->d1->buffered_app_data);
746
747 if (dtls1_handle_timeout(s) > 0)
748 goto start;
749
750 if (rr->length == 0 || s->internal->rstate == SSL_ST_READ_BODY) {
751 if ((ret = dtls1_get_record(s)) <= 0) {
752 /* Anything other than a timeout is an error. */
753 if ((ret = dtls1_read_failed(s, ret)) <= 0)
754 return ret;
755 goto start;
756 }
757 }
758
759 if (s->d1->listen && rr->type != SSL3_RT_HANDSHAKE) {
760 rr->length = 0;
761 goto start;
762 }
763
764 /* We now have a packet which can be read and processed. */
765
766 if (s->s3->change_cipher_spec && rr->type != SSL3_RT_HANDSHAKE) {
767 /*
768 * We now have application data between CCS and Finished.
769 * Most likely the packets were reordered on their way, so
770 * buffer the application data for later processing rather
771 * than dropping the connection.
772 */
773 if (dtls1_buffer_record(s, &s->d1->buffered_app_data,
774 rr->seq_num) < 0) {
775 SSLerror(s, ERR_R_INTERNAL_ERROR);
776 return (-1);
777 }
778 rr->length = 0;
779 goto start;
780 }
781
782 /*
783 * If the other end has shut down, throw anything we read away (even in
784 * 'peek' mode).
785 */
786 if (s->internal->shutdown & SSL_RECEIVED_SHUTDOWN) {
787 s->internal->rwstate = SSL_NOTHING;
788 rr->length = 0;
789 return 0;
790 }
791
792 /* SSL3_RT_APPLICATION_DATA or SSL3_RT_HANDSHAKE */
793 if (type == rr->type) {
794 /*
795 * Make sure that we are not getting application data when we
796 * are doing a handshake for the first time.
797 */
798 if (SSL_in_init(s) && type == SSL3_RT_APPLICATION_DATA &&
799 !tls12_record_layer_read_protected(s->internal->rl)) {
800 SSLerror(s, SSL_R_APP_DATA_IN_HANDSHAKE);
801 ssl3_send_alert(s, SSL3_AL_FATAL,
802 SSL_AD_UNEXPECTED_MESSAGE);
803 return -1;
804 }
805
806 if (len <= 0)
807 return len;
808
809 if ((unsigned int)len > rr->length)
810 n = rr->length;
811 else
812 n = (unsigned int)len;
813
814 memcpy(buf, &rr->data[rr->off], n);
815 if (!peek) {
816 memset(&rr->data[rr->off], 0, n);
817 rr->length -= n;
818 rr->off += n;
819 if (rr->length == 0) {
820 s->internal->rstate = SSL_ST_READ_HEADER;
821 rr->off = 0;
822 }
823 }
824
825 return n;
826 }
827
828 /*
829 * If we get here, then type != rr->type; if we have a handshake
830 * message, then it was unexpected (Hello Request or Client Hello).
831 */
832
833 if (rr->type == SSL3_RT_ALERT) {
834 if ((ret = ssl3_read_alert(s)) <= 0)
835 return ret;
836 goto start;
837 }
838
839 if (s->internal->shutdown & SSL_SENT_SHUTDOWN) {
840 s->internal->rwstate = SSL_NOTHING;
841 rr->length = 0;
842 return (0);
843 }
844
845 if (rr->type == SSL3_RT_APPLICATION_DATA) {
846 /*
847 * At this point, we were expecting handshake data, but have
848 * application data. If the library was running inside
849 * ssl3_read() (i.e. in_read_app_data is set) and it makes
850 * sense to read application data at this point (session
851 * renegotiation not yet started), we will indulge it.
852 */
853 if (s->s3->in_read_app_data != 0 &&
854 s->s3->total_renegotiations != 0 &&
855 (((s->s3->hs.state & SSL_ST_CONNECT) &&
856 (s->s3->hs.state >= SSL3_ST_CW_CLNT_HELLO_A) &&
857 (s->s3->hs.state <= SSL3_ST_CR_SRVR_HELLO_A)) || (
858 (s->s3->hs.state & SSL_ST_ACCEPT) &&
859 (s->s3->hs.state <= SSL3_ST_SW_HELLO_REQ_A) &&
860 (s->s3->hs.state >= SSL3_ST_SR_CLNT_HELLO_A)))) {
861 s->s3->in_read_app_data = 2;
862 return -1;
863 } else {
864 SSLerror(s, SSL_R_UNEXPECTED_RECORD);
865 ssl3_send_alert(s, SSL3_AL_FATAL,
866 SSL_AD_UNEXPECTED_MESSAGE);
867 return -1;
868 }
869 }
870
871 if (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC) {
872 if ((ret = ssl3_read_change_cipher_spec(s)) <= 0)
873 return ret;
874 goto start;
875 }
876
877 if (rr->type == SSL3_RT_HANDSHAKE) {
878 if ((ret = dtls1_read_handshake_unexpected(s)) <= 0)
879 return ret;
880 goto start;
881 }
882
883 /* Unknown record type. */
884 SSLerror(s, SSL_R_UNEXPECTED_RECORD);
885 ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
886 return -1;
887 }
888
889 int
dtls1_write_app_data_bytes(SSL * s,int type,const void * buf_,int len)890 dtls1_write_app_data_bytes(SSL *s, int type, const void *buf_, int len)
891 {
892 int i;
893
894 if (SSL_in_init(s) && !s->internal->in_handshake)
895 {
896 i = s->internal->handshake_func(s);
897 if (i < 0)
898 return (i);
899 if (i == 0) {
900 SSLerror(s, SSL_R_SSL_HANDSHAKE_FAILURE);
901 return -1;
902 }
903 }
904
905 if (len > SSL3_RT_MAX_PLAIN_LENGTH) {
906 SSLerror(s, SSL_R_DTLS_MESSAGE_TOO_BIG);
907 return -1;
908 }
909
910 i = dtls1_write_bytes(s, type, buf_, len);
911 return i;
912 }
913
914 /* Call this to write data in records of type 'type'
915 * It will return <= 0 if not all data has been sent or non-blocking IO.
916 */
917 int
dtls1_write_bytes(SSL * s,int type,const void * buf,int len)918 dtls1_write_bytes(SSL *s, int type, const void *buf, int len)
919 {
920 int i;
921
922 OPENSSL_assert(len <= SSL3_RT_MAX_PLAIN_LENGTH);
923 s->internal->rwstate = SSL_NOTHING;
924 i = do_dtls1_write(s, type, buf, len);
925 return i;
926 }
927
928 int
do_dtls1_write(SSL * s,int type,const unsigned char * buf,unsigned int len)929 do_dtls1_write(SSL *s, int type, const unsigned char *buf, unsigned int len)
930 {
931 SSL3_BUFFER_INTERNAL *wb = &(s->s3->wbuf);
932 size_t out_len;
933 CBB cbb;
934 int ret;
935
936 memset(&cbb, 0, sizeof(cbb));
937
938 /*
939 * First check if there is a SSL3_BUFFER_INTERNAL still being written
940 * out. This will happen with non blocking IO.
941 */
942 if (wb->left != 0) {
943 OPENSSL_assert(0); /* XDTLS: want to see if we ever get here */
944 return (ssl3_write_pending(s, type, buf, len));
945 }
946
947 /* If we have an alert to send, let's send it */
948 if (s->s3->alert_dispatch) {
949 if ((ret = ssl3_dispatch_alert(s)) <= 0)
950 return (ret);
951 /* If it went, fall through and send more stuff. */
952 }
953
954 if (len == 0)
955 return 0;
956
957 wb->offset = 0;
958
959 if (!CBB_init_fixed(&cbb, wb->buf, wb->len))
960 goto err;
961
962 tls12_record_layer_set_version(s->internal->rl, s->version);
963
964 if (!tls12_record_layer_seal_record(s->internal->rl, type, buf, len, &cbb))
965 goto err;
966
967 if (!CBB_finish(&cbb, NULL, &out_len))
968 goto err;
969
970 wb->left = out_len;
971
972 /*
973 * Memorize arguments so that ssl3_write_pending can detect
974 * bad write retries later.
975 */
976 s->s3->wpend_tot = len;
977 s->s3->wpend_buf = buf;
978 s->s3->wpend_type = type;
979 s->s3->wpend_ret = len;
980
981 /* We now just need to write the buffer. */
982 return ssl3_write_pending(s, type, buf, len);
983
984 err:
985 CBB_cleanup(&cbb);
986
987 return -1;
988 }
989
990 static int
dtls1_record_replay_check(SSL * s,DTLS1_BITMAP * bitmap,const unsigned char * seq)991 dtls1_record_replay_check(SSL *s, DTLS1_BITMAP *bitmap,
992 const unsigned char *seq)
993 {
994 unsigned int shift;
995 int cmp;
996
997 cmp = satsub64be(seq, bitmap->max_seq_num);
998 if (cmp > 0)
999 return 1; /* this record in new */
1000 shift = -cmp;
1001 if (shift >= sizeof(bitmap->map)*8)
1002 return 0; /* stale, outside the window */
1003 else if (bitmap->map & (1UL << shift))
1004 return 0; /* record previously received */
1005
1006 return 1;
1007 }
1008
1009 static void
dtls1_record_bitmap_update(SSL * s,DTLS1_BITMAP * bitmap,const unsigned char * seq)1010 dtls1_record_bitmap_update(SSL *s, DTLS1_BITMAP *bitmap,
1011 const unsigned char *seq)
1012 {
1013 unsigned int shift;
1014 int cmp;
1015
1016 cmp = satsub64be(seq, bitmap->max_seq_num);
1017 if (cmp > 0) {
1018 shift = cmp;
1019 if (shift < sizeof(bitmap->map)*8)
1020 bitmap->map <<= shift, bitmap->map |= 1UL;
1021 else
1022 bitmap->map = 1UL;
1023 memcpy(bitmap->max_seq_num, seq, 8);
1024 } else {
1025 shift = -cmp;
1026 if (shift < sizeof(bitmap->map) * 8)
1027 bitmap->map |= 1UL << shift;
1028 }
1029 }
1030
1031 static DTLS1_BITMAP *
dtls1_get_bitmap(SSL * s,SSL3_RECORD_INTERNAL * rr,unsigned int * is_next_epoch)1032 dtls1_get_bitmap(SSL *s, SSL3_RECORD_INTERNAL *rr, unsigned int *is_next_epoch)
1033 {
1034 uint16_t read_epoch, read_epoch_next;
1035
1036 *is_next_epoch = 0;
1037
1038 read_epoch = tls12_record_layer_read_epoch(s->internal->rl);
1039 read_epoch_next = read_epoch + 1;
1040
1041 /* In current epoch, accept HM, CCS, DATA, & ALERT */
1042 if (rr->epoch == read_epoch)
1043 return &s->d1->bitmap;
1044
1045 /* Only HM and ALERT messages can be from the next epoch */
1046 if (rr->epoch == read_epoch_next &&
1047 (rr->type == SSL3_RT_HANDSHAKE || rr->type == SSL3_RT_ALERT)) {
1048 *is_next_epoch = 1;
1049 return &s->d1->next_bitmap;
1050 }
1051
1052 return NULL;
1053 }
1054
1055 void
dtls1_reset_read_seq_numbers(SSL * s)1056 dtls1_reset_read_seq_numbers(SSL *s)
1057 {
1058 memcpy(&(s->d1->bitmap), &(s->d1->next_bitmap), sizeof(DTLS1_BITMAP));
1059 memset(&(s->d1->next_bitmap), 0, sizeof(DTLS1_BITMAP));
1060 }
1061