1 /*
2 * Copyright 2005-2021 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10 #include <stdio.h>
11 #include <errno.h>
12 #include "../ssl_local.h"
13 #include <openssl/evp.h>
14 #include <openssl/buffer.h>
15 #include "record_local.h"
16 #include "internal/packet.h"
17 #include "internal/cryptlib.h"
18
DTLS_RECORD_LAYER_new(RECORD_LAYER * rl)19 int DTLS_RECORD_LAYER_new(RECORD_LAYER *rl)
20 {
21 DTLS_RECORD_LAYER *d;
22
23 if ((d = OPENSSL_malloc(sizeof(*d))) == NULL) {
24 ERR_raise(ERR_LIB_SSL, ERR_R_MALLOC_FAILURE);
25 return 0;
26 }
27
28 rl->d = d;
29
30 d->buffered_app_data.q = pqueue_new();
31
32 if (d->buffered_app_data.q == NULL) {
33 OPENSSL_free(d);
34 rl->d = NULL;
35 return 0;
36 }
37
38 return 1;
39 }
40
DTLS_RECORD_LAYER_free(RECORD_LAYER * rl)41 void DTLS_RECORD_LAYER_free(RECORD_LAYER *rl)
42 {
43 if (rl->d == NULL)
44 return;
45
46 DTLS_RECORD_LAYER_clear(rl);
47 pqueue_free(rl->d->buffered_app_data.q);
48 OPENSSL_free(rl->d);
49 rl->d = NULL;
50 }
51
DTLS_RECORD_LAYER_clear(RECORD_LAYER * rl)52 void DTLS_RECORD_LAYER_clear(RECORD_LAYER *rl)
53 {
54 DTLS_RECORD_LAYER *d;
55 pitem *item = NULL;
56 TLS_RECORD *rec;
57 pqueue *buffered_app_data;
58
59 d = rl->d;
60
61 while ((item = pqueue_pop(d->buffered_app_data.q)) != NULL) {
62 rec = (TLS_RECORD *)item->data;
63 if (rl->s->options & SSL_OP_CLEANSE_PLAINTEXT)
64 OPENSSL_cleanse(rec->data, rec->length);
65 OPENSSL_free(rec->data);
66 OPENSSL_free(item->data);
67 pitem_free(item);
68 }
69
70 buffered_app_data = d->buffered_app_data.q;
71 memset(d, 0, sizeof(*d));
72 d->buffered_app_data.q = buffered_app_data;
73 }
74
DTLS_RECORD_LAYER_set_saved_w_epoch(RECORD_LAYER * rl,unsigned short e)75 void DTLS_RECORD_LAYER_set_saved_w_epoch(RECORD_LAYER *rl, unsigned short e)
76 {
77 if (e == rl->d->w_epoch - 1) {
78 memcpy(rl->d->curr_write_sequence,
79 rl->write_sequence, sizeof(rl->write_sequence));
80 memcpy(rl->write_sequence,
81 rl->d->last_write_sequence, sizeof(rl->write_sequence));
82 } else if (e == rl->d->w_epoch + 1) {
83 memcpy(rl->d->last_write_sequence,
84 rl->write_sequence, sizeof(unsigned char[8]));
85 memcpy(rl->write_sequence,
86 rl->d->curr_write_sequence, sizeof(rl->write_sequence));
87 }
88 rl->d->w_epoch = e;
89 }
90
DTLS_RECORD_LAYER_set_write_sequence(RECORD_LAYER * rl,unsigned char * seq)91 void DTLS_RECORD_LAYER_set_write_sequence(RECORD_LAYER *rl, unsigned char *seq)
92 {
93 memcpy(rl->write_sequence, seq, SEQ_NUM_SIZE);
94 }
95
dtls_buffer_record(SSL_CONNECTION * s,TLS_RECORD * rec)96 int dtls_buffer_record(SSL_CONNECTION *s, TLS_RECORD *rec)
97 {
98 TLS_RECORD *rdata;
99 pitem *item;
100 record_pqueue *queue = &(s->rlayer.d->buffered_app_data);
101
102 /* Limit the size of the queue to prevent DOS attacks */
103 if (pqueue_size(queue->q) >= 100)
104 return 0;
105
106 /* We don't buffer partially read records */
107 if (!ossl_assert(rec->off == 0))
108 return -1;
109
110 rdata = OPENSSL_malloc(sizeof(*rdata));
111 item = pitem_new(rec->seq_num, rdata);
112 if (rdata == NULL || item == NULL) {
113 OPENSSL_free(rdata);
114 pitem_free(item);
115 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
116 return -1;
117 }
118
119 *rdata = *rec;
120 /*
121 * We will release the record from the record layer soon, so we take a copy
122 * now. Copying data isn't good - but this should be infrequent so we
123 * accept it here.
124 */
125 rdata->data = OPENSSL_memdup(rec->data, rec->length);
126 if (rdata->data == NULL) {
127 OPENSSL_free(rdata);
128 pitem_free(item);
129 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_MALLOC_FAILURE);
130 return -1;
131 }
132 /*
133 * We use a NULL rechandle to indicate that the data field has been
134 * allocated by us.
135 */
136 rdata->rechandle = NULL;
137
138 item->data = rdata;
139
140 #ifndef OPENSSL_NO_SCTP
141 /* Store bio_dgram_sctp_rcvinfo struct */
142 if (BIO_dgram_is_sctp(SSL_get_rbio(ssl)) &&
143 (SSL_get_state(ssl) == TLS_ST_SR_FINISHED
144 || SSL_get_state(ssl) == TLS_ST_CR_FINISHED)) {
145 BIO_ctrl(SSL_get_rbio(ssl), BIO_CTRL_DGRAM_SCTP_GET_RCVINFO,
146 sizeof(rdata->recordinfo), &rdata->recordinfo);
147 }
148 #endif
149
150 if (pqueue_insert(queue->q, item) == NULL) {
151 /* Must be a duplicate so ignore it */
152 OPENSSL_free(rdata->data);
153 OPENSSL_free(rdata);
154 pitem_free(item);
155 }
156
157 return 1;
158 }
159
160 /* Unbuffer a previously buffered TLS_RECORD structure if any */
dtls_unbuffer_record(SSL_CONNECTION * s)161 static void dtls_unbuffer_record(SSL_CONNECTION *s)
162 {
163 TLS_RECORD *rdata;
164 pitem *item;
165
166 /* If we already have records to handle then do nothing */
167 if (s->rlayer.curr_rec < s->rlayer.num_recs)
168 return;
169
170 item = pqueue_pop(s->rlayer.d->buffered_app_data.q);
171 if (item != NULL) {
172 rdata = (TLS_RECORD *)item->data;
173
174 s->rlayer.tlsrecs[0] = *rdata;
175 s->rlayer.num_recs = 1;
176 s->rlayer.curr_rec = 0;
177
178 #ifndef OPENSSL_NO_SCTP
179 /* Restore bio_dgram_sctp_rcvinfo struct */
180 if (BIO_dgram_is_sctp(SSL_get_rbio(s))) {
181 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SCTP_SET_RCVINFO,
182 sizeof(rdata->recordinfo), &rdata->recordinfo);
183 }
184 #endif
185
186 OPENSSL_free(item->data);
187 pitem_free(item);
188 }
189 }
190
191 /*-
192 * Return up to 'len' payload bytes received in 'type' records.
193 * 'type' is one of the following:
194 *
195 * - SSL3_RT_HANDSHAKE (when ssl3_get_message calls us)
196 * - SSL3_RT_APPLICATION_DATA (when ssl3_read calls us)
197 * - 0 (during a shutdown, no data has to be returned)
198 *
199 * If we don't have stored data to work from, read a SSL/TLS record first
200 * (possibly multiple records if we still don't have anything to return).
201 *
202 * This function must handle any surprises the peer may have for us, such as
203 * Alert records (e.g. close_notify) or renegotiation requests. ChangeCipherSpec
204 * messages are treated as if they were handshake messages *if* the |recd_type|
205 * argument is non NULL.
206 * Also if record payloads contain fragments too small to process, we store
207 * them until there is enough for the respective protocol (the record protocol
208 * may use arbitrary fragmentation and even interleaving):
209 * Change cipher spec protocol
210 * just 1 byte needed, no need for keeping anything stored
211 * Alert protocol
212 * 2 bytes needed (AlertLevel, AlertDescription)
213 * Handshake protocol
214 * 4 bytes needed (HandshakeType, uint24 length) -- we just have
215 * to detect unexpected Client Hello and Hello Request messages
216 * here, anything else is handled by higher layers
217 * Application data protocol
218 * none of our business
219 */
dtls1_read_bytes(SSL * s,int type,int * recvd_type,unsigned char * buf,size_t len,int peek,size_t * readbytes)220 int dtls1_read_bytes(SSL *s, int type, int *recvd_type, unsigned char *buf,
221 size_t len, int peek, size_t *readbytes)
222 {
223 int i, j, ret;
224 size_t n;
225 TLS_RECORD *rr;
226 void (*cb) (const SSL *ssl, int type2, int val) = NULL;
227 SSL_CONNECTION *sc = SSL_CONNECTION_FROM_SSL(s);
228
229 if (sc == NULL)
230 return -1;
231
232 if ((type && (type != SSL3_RT_APPLICATION_DATA) &&
233 (type != SSL3_RT_HANDSHAKE)) ||
234 (peek && (type != SSL3_RT_APPLICATION_DATA))) {
235 SSLfatal(sc, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
236 return -1;
237 }
238
239 if (!ossl_statem_get_in_handshake(sc) && SSL_in_init(s)) {
240 /* type == SSL3_RT_APPLICATION_DATA */
241 i = sc->handshake_func(s);
242 /* SSLfatal() already called if appropriate */
243 if (i < 0)
244 return i;
245 if (i == 0)
246 return -1;
247 }
248
249 start:
250 sc->rwstate = SSL_NOTHING;
251
252 /*
253 * We are not handshaking and have no data yet, so process data buffered
254 * during the last handshake in advance, if any.
255 */
256 if (SSL_is_init_finished(s))
257 dtls_unbuffer_record(sc);
258
259 /* Check for timeout */
260 if (dtls1_handle_timeout(sc) > 0) {
261 goto start;
262 } else if (ossl_statem_in_error(sc)) {
263 /* dtls1_handle_timeout() has failed with a fatal error */
264 return -1;
265 }
266
267 /* get new packet if necessary */
268 if (sc->rlayer.curr_rec >= sc->rlayer.num_recs) {
269 sc->rlayer.curr_rec = sc->rlayer.num_recs = 0;
270 do {
271 rr = &sc->rlayer.tlsrecs[sc->rlayer.num_recs];
272
273 ret = HANDLE_RLAYER_RETURN(sc,
274 sc->rlayer.rrlmethod->read_record(sc->rlayer.rrl,
275 &rr->rechandle,
276 &rr->version, &rr->type,
277 &rr->data, &rr->length,
278 &rr->epoch, rr->seq_num));
279 if (ret <= 0) {
280 ret = dtls1_read_failed(sc, ret);
281 /*
282 * Anything other than a timeout is an error. SSLfatal() already
283 * called if appropriate.
284 */
285 if (ret <= 0)
286 return ret;
287 else
288 goto start;
289 }
290 rr->off = 0;
291 sc->rlayer.num_recs++;
292 } while (sc->rlayer.rrlmethod->processed_read_pending(sc->rlayer.rrl)
293 && sc->rlayer.num_recs < SSL_MAX_PIPELINES);
294 }
295 rr = &sc->rlayer.tlsrecs[sc->rlayer.curr_rec];
296
297 /*
298 * Reset the count of consecutive warning alerts if we've got a non-empty
299 * record that isn't an alert.
300 */
301 if (rr->type != SSL3_RT_ALERT && rr->length != 0)
302 sc->rlayer.alert_count = 0;
303
304 /* we now have a packet which can be read and processed */
305
306 if (sc->s3.change_cipher_spec /* set when we receive ChangeCipherSpec,
307 * reset by ssl3_get_finished */
308 && (rr->type != SSL3_RT_HANDSHAKE)) {
309 /*
310 * We now have application data between CCS and Finished. Most likely
311 * the packets were reordered on their way, so buffer the application
312 * data for later processing rather than dropping the connection.
313 */
314 if (dtls_buffer_record(sc, rr) < 0) {
315 /* SSLfatal() already called */
316 return -1;
317 }
318 ssl_release_record(sc, rr);
319 goto start;
320 }
321
322 /*
323 * If the other end has shut down, throw anything we read away (even in
324 * 'peek' mode)
325 */
326 if (sc->shutdown & SSL_RECEIVED_SHUTDOWN) {
327 ssl_release_record(sc, rr);
328 sc->rwstate = SSL_NOTHING;
329 return 0;
330 }
331
332 if (type == rr->type
333 || (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC
334 && type == SSL3_RT_HANDSHAKE && recvd_type != NULL)) {
335 /*
336 * SSL3_RT_APPLICATION_DATA or
337 * SSL3_RT_HANDSHAKE or
338 * SSL3_RT_CHANGE_CIPHER_SPEC
339 */
340 /*
341 * make sure that we are not getting application data when we are
342 * doing a handshake for the first time
343 */
344 if (SSL_in_init(s) && (type == SSL3_RT_APPLICATION_DATA) &&
345 (sc->enc_read_ctx == NULL)) {
346 SSLfatal(sc, SSL_AD_UNEXPECTED_MESSAGE,
347 SSL_R_APP_DATA_IN_HANDSHAKE);
348 return -1;
349 }
350
351 if (recvd_type != NULL)
352 *recvd_type = rr->type;
353
354 if (len == 0) {
355 /*
356 * Release a zero length record. This ensures multiple calls to
357 * SSL_read() with a zero length buffer will eventually cause
358 * SSL_pending() to report data as being available.
359 */
360 if (rr->length == 0)
361 ssl_release_record(sc, rr);
362 return 0;
363 }
364
365 if (len > rr->length)
366 n = rr->length;
367 else
368 n = len;
369
370 memcpy(buf, &(rr->data[rr->off]), n);
371 if (peek) {
372 if (rr->length == 0)
373 ssl_release_record(sc, rr);
374 } else {
375 if (sc->options & SSL_OP_CLEANSE_PLAINTEXT)
376 OPENSSL_cleanse(&(rr->data[rr->off]), n);
377 rr->length -= n;
378 rr->off += n;
379 if (rr->length == 0)
380 ssl_release_record(sc, rr);
381 }
382 #ifndef OPENSSL_NO_SCTP
383 /*
384 * We might had to delay a close_notify alert because of reordered
385 * app data. If there was an alert and there is no message to read
386 * anymore, finally set shutdown.
387 */
388 if (BIO_dgram_is_sctp(SSL_get_rbio(s)) &&
389 sc->d1->shutdown_received
390 && BIO_dgram_sctp_msg_waiting(SSL_get_rbio(s)) <= 0) {
391 sc->shutdown |= SSL_RECEIVED_SHUTDOWN;
392 return 0;
393 }
394 #endif
395 *readbytes = n;
396 return 1;
397 }
398
399 /*
400 * If we get here, then type != rr->type; if we have a handshake message,
401 * then it was unexpected (Hello Request or Client Hello).
402 */
403
404 if (rr->type == SSL3_RT_ALERT) {
405 unsigned int alert_level, alert_descr;
406 unsigned char *alert_bytes = rr->data + rr->off;
407 PACKET alert;
408
409 if (!PACKET_buf_init(&alert, alert_bytes, rr->length)
410 || !PACKET_get_1(&alert, &alert_level)
411 || !PACKET_get_1(&alert, &alert_descr)
412 || PACKET_remaining(&alert) != 0) {
413 SSLfatal(sc, SSL_AD_UNEXPECTED_MESSAGE, SSL_R_INVALID_ALERT);
414 return -1;
415 }
416
417 if (sc->msg_callback)
418 sc->msg_callback(0, sc->version, SSL3_RT_ALERT, alert_bytes, 2, s,
419 sc->msg_callback_arg);
420
421 if (sc->info_callback != NULL)
422 cb = sc->info_callback;
423 else if (s->ctx->info_callback != NULL)
424 cb = s->ctx->info_callback;
425
426 if (cb != NULL) {
427 j = (alert_level << 8) | alert_descr;
428 cb(s, SSL_CB_READ_ALERT, j);
429 }
430
431 if (alert_level == SSL3_AL_WARNING) {
432 sc->s3.warn_alert = alert_descr;
433 ssl_release_record(sc, rr);
434
435 sc->rlayer.alert_count++;
436 if (sc->rlayer.alert_count == MAX_WARN_ALERT_COUNT) {
437 SSLfatal(sc, SSL_AD_UNEXPECTED_MESSAGE,
438 SSL_R_TOO_MANY_WARN_ALERTS);
439 return -1;
440 }
441
442 if (alert_descr == SSL_AD_CLOSE_NOTIFY) {
443 #ifndef OPENSSL_NO_SCTP
444 /*
445 * With SCTP and streams the socket may deliver app data
446 * after a close_notify alert. We have to check this first so
447 * that nothing gets discarded.
448 */
449 if (BIO_dgram_is_sctp(SSL_get_rbio(s)) &&
450 BIO_dgram_sctp_msg_waiting(SSL_get_rbio(s)) > 0) {
451 sc->d1->shutdown_received = 1;
452 sc->rwstate = SSL_READING;
453 BIO_clear_retry_flags(SSL_get_rbio(s));
454 BIO_set_retry_read(SSL_get_rbio(s));
455 return -1;
456 }
457 #endif
458 sc->shutdown |= SSL_RECEIVED_SHUTDOWN;
459 return 0;
460 }
461 } else if (alert_level == SSL3_AL_FATAL) {
462 sc->rwstate = SSL_NOTHING;
463 sc->s3.fatal_alert = alert_descr;
464 SSLfatal_data(sc, SSL_AD_NO_ALERT,
465 SSL_AD_REASON_OFFSET + alert_descr,
466 "SSL alert number %d", alert_descr);
467 sc->shutdown |= SSL_RECEIVED_SHUTDOWN;
468 ssl_release_record(sc, rr);
469 SSL_CTX_remove_session(sc->session_ctx, sc->session);
470 return 0;
471 } else {
472 SSLfatal(sc, SSL_AD_ILLEGAL_PARAMETER, SSL_R_UNKNOWN_ALERT_TYPE);
473 return -1;
474 }
475
476 goto start;
477 }
478
479 if (sc->shutdown & SSL_SENT_SHUTDOWN) { /* but we have not received a
480 * shutdown */
481 sc->rwstate = SSL_NOTHING;
482 ssl_release_record(sc, rr);
483 return 0;
484 }
485
486 if (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC) {
487 /*
488 * We can't process a CCS now, because previous handshake messages
489 * are still missing, so just drop it.
490 */
491 ssl_release_record(sc, rr);
492 goto start;
493 }
494
495 /*
496 * Unexpected handshake message (Client Hello, or protocol violation)
497 */
498 if (rr->type == SSL3_RT_HANDSHAKE && !ossl_statem_get_in_handshake(sc)) {
499 struct hm_header_st msg_hdr;
500
501 /*
502 * This may just be a stale retransmit. Also sanity check that we have
503 * at least enough record bytes for a message header
504 */
505 if (rr->epoch != sc->rlayer.d->r_epoch
506 || rr->length < DTLS1_HM_HEADER_LENGTH) {
507 ssl_release_record(sc, rr);
508 goto start;
509 }
510
511 dtls1_get_message_header(rr->data, &msg_hdr);
512
513 /*
514 * If we are server, we may have a repeated FINISHED of the client
515 * here, then retransmit our CCS and FINISHED.
516 */
517 if (msg_hdr.type == SSL3_MT_FINISHED) {
518 if (dtls1_check_timeout_num(sc) < 0) {
519 /* SSLfatal) already called */
520 return -1;
521 }
522
523 if (dtls1_retransmit_buffered_messages(sc) <= 0) {
524 /* Fail if we encountered a fatal error */
525 if (ossl_statem_in_error(sc))
526 return -1;
527 }
528 ssl_release_record(sc, rr);
529 if (!(sc->mode & SSL_MODE_AUTO_RETRY)) {
530 if (!sc->rlayer.rrlmethod->unprocessed_read_pending(sc->rlayer.rrl)) {
531 /* no read-ahead left? */
532 BIO *bio;
533
534 sc->rwstate = SSL_READING;
535 bio = SSL_get_rbio(s);
536 BIO_clear_retry_flags(bio);
537 BIO_set_retry_read(bio);
538 return -1;
539 }
540 }
541 goto start;
542 }
543
544 /*
545 * To get here we must be trying to read app data but found handshake
546 * data. But if we're trying to read app data, and we're not in init
547 * (which is tested for at the top of this function) then init must be
548 * finished
549 */
550 if (!ossl_assert(SSL_is_init_finished(s))) {
551 SSLfatal(sc, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
552 return -1;
553 }
554
555 /* We found handshake data, so we're going back into init */
556 ossl_statem_set_in_init(sc, 1);
557
558 i = sc->handshake_func(s);
559 /* SSLfatal() called if appropriate */
560 if (i < 0)
561 return i;
562 if (i == 0)
563 return -1;
564
565 if (!(sc->mode & SSL_MODE_AUTO_RETRY)) {
566 if (!sc->rlayer.rrlmethod->unprocessed_read_pending(sc->rlayer.rrl)) {
567 /* no read-ahead left? */
568 BIO *bio;
569 /*
570 * In the case where we try to read application data, but we
571 * trigger an SSL handshake, we return -1 with the retry
572 * option set. Otherwise renegotiation may cause nasty
573 * problems in the blocking world
574 */
575 sc->rwstate = SSL_READING;
576 bio = SSL_get_rbio(s);
577 BIO_clear_retry_flags(bio);
578 BIO_set_retry_read(bio);
579 return -1;
580 }
581 }
582 goto start;
583 }
584
585 switch (rr->type) {
586 default:
587 SSLfatal(sc, SSL_AD_UNEXPECTED_MESSAGE, SSL_R_UNEXPECTED_RECORD);
588 return -1;
589 case SSL3_RT_CHANGE_CIPHER_SPEC:
590 case SSL3_RT_ALERT:
591 case SSL3_RT_HANDSHAKE:
592 /*
593 * we already handled all of these, with the possible exception of
594 * SSL3_RT_HANDSHAKE when ossl_statem_get_in_handshake(s) is true, but
595 * that should not happen when type != rr->type
596 */
597 SSLfatal(sc, SSL_AD_UNEXPECTED_MESSAGE, ERR_R_INTERNAL_ERROR);
598 return -1;
599 case SSL3_RT_APPLICATION_DATA:
600 /*
601 * At this point, we were expecting handshake data, but have
602 * application data. If the library was running inside ssl3_read()
603 * (i.e. in_read_app_data is set) and it makes sense to read
604 * application data at this point (session renegotiation not yet
605 * started), we will indulge it.
606 */
607 if (sc->s3.in_read_app_data &&
608 (sc->s3.total_renegotiations != 0) &&
609 ossl_statem_app_data_allowed(sc)) {
610 sc->s3.in_read_app_data = 2;
611 return -1;
612 } else {
613 SSLfatal(sc, SSL_AD_UNEXPECTED_MESSAGE, SSL_R_UNEXPECTED_RECORD);
614 return -1;
615 }
616 }
617 /* not reached */
618 }
619
620 /*
621 * Call this to write data in records of type 'type' It will return <= 0 if
622 * not all data has been sent or non-blocking IO.
623 */
dtls1_write_bytes(SSL_CONNECTION * s,int type,const void * buf,size_t len,size_t * written)624 int dtls1_write_bytes(SSL_CONNECTION *s, int type, const void *buf,
625 size_t len, size_t *written)
626 {
627 int i;
628
629 if (!ossl_assert(len <= SSL3_RT_MAX_PLAIN_LENGTH)) {
630 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
631 return -1;
632 }
633 s->rwstate = SSL_NOTHING;
634 i = do_dtls1_write(s, type, buf, len, 0, written);
635 return i;
636 }
637
do_dtls1_write(SSL_CONNECTION * sc,int type,const unsigned char * buf,size_t len,int create_empty_fragment,size_t * written)638 int do_dtls1_write(SSL_CONNECTION *sc, int type, const unsigned char *buf,
639 size_t len, int create_empty_fragment, size_t *written)
640 {
641 unsigned char *p, *pseq;
642 int i, mac_size, clear = 0;
643 size_t prefix_len = 0;
644 int eivlen;
645 SSL3_RECORD wr;
646 SSL3_BUFFER *wb;
647 SSL_SESSION *sess;
648 SSL *s = SSL_CONNECTION_GET_SSL(sc);
649
650 wb = &sc->rlayer.wbuf[0];
651
652 /*
653 * DTLS writes whole datagrams, so there can't be anything left in
654 * the buffer.
655 */
656 if (!ossl_assert(SSL3_BUFFER_get_left(wb) == 0)) {
657 SSLfatal(sc, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
658 return 0;
659 }
660
661 /* If we have an alert to send, lets send it */
662 if (sc->s3.alert_dispatch) {
663 i = s->method->ssl_dispatch_alert(s);
664 if (i <= 0)
665 return i;
666 /* if it went, fall through and send more stuff */
667 }
668
669 if (len == 0 && !create_empty_fragment)
670 return 0;
671
672 if (len > ssl_get_max_send_fragment(sc)) {
673 SSLfatal(sc, SSL_AD_INTERNAL_ERROR, SSL_R_EXCEEDS_MAX_FRAGMENT_SIZE);
674 return 0;
675 }
676
677 sess = sc->session;
678
679 if ((sess == NULL)
680 || (sc->enc_write_ctx == NULL)
681 || (EVP_MD_CTX_get0_md(sc->write_hash) == NULL))
682 clear = 1;
683
684 if (clear)
685 mac_size = 0;
686 else {
687 mac_size = EVP_MD_CTX_get_size(sc->write_hash);
688 if (mac_size < 0) {
689 SSLfatal(sc, SSL_AD_INTERNAL_ERROR,
690 SSL_R_EXCEEDS_MAX_FRAGMENT_SIZE);
691 return -1;
692 }
693 }
694
695 p = SSL3_BUFFER_get_buf(wb) + prefix_len;
696
697 /* write the header */
698
699 *(p++) = type & 0xff;
700 SSL3_RECORD_set_type(&wr, type);
701 /*
702 * Special case: for hello verify request, client version 1.0 and we
703 * haven't decided which version to use yet send back using version 1.0
704 * header: otherwise some clients will ignore it.
705 */
706 if (s->method->version == DTLS_ANY_VERSION &&
707 sc->max_proto_version != DTLS1_BAD_VER) {
708 *(p++) = DTLS1_VERSION >> 8;
709 *(p++) = DTLS1_VERSION & 0xff;
710 } else {
711 *(p++) = sc->version >> 8;
712 *(p++) = sc->version & 0xff;
713 }
714
715 /* field where we are to write out packet epoch, seq num and len */
716 pseq = p;
717 p += 10;
718
719 /* Explicit IV length, block ciphers appropriate version flag */
720 if (sc->enc_write_ctx) {
721 int mode = EVP_CIPHER_CTX_get_mode(sc->enc_write_ctx);
722 if (mode == EVP_CIPH_CBC_MODE) {
723 eivlen = EVP_CIPHER_CTX_get_iv_length(sc->enc_write_ctx);
724 if (eivlen < 0) {
725 SSLfatal(sc, SSL_AD_INTERNAL_ERROR, SSL_R_LIBRARY_BUG);
726 return -1;
727 }
728 if (eivlen <= 1)
729 eivlen = 0;
730 }
731 /* Need explicit part of IV for GCM mode */
732 else if (mode == EVP_CIPH_GCM_MODE)
733 eivlen = EVP_GCM_TLS_EXPLICIT_IV_LEN;
734 else if (mode == EVP_CIPH_CCM_MODE)
735 eivlen = EVP_CCM_TLS_EXPLICIT_IV_LEN;
736 else
737 eivlen = 0;
738 } else
739 eivlen = 0;
740
741 /* lets setup the record stuff. */
742 SSL3_RECORD_set_data(&wr, p + eivlen); /* make room for IV in case of CBC */
743 SSL3_RECORD_set_length(&wr, len);
744 SSL3_RECORD_set_input(&wr, (unsigned char *)buf);
745
746 /*
747 * we now 'read' from wr.input, wr.length bytes into wr.data
748 */
749
750 /* first we compress */
751 if (sc->compress != NULL) {
752 if (!ssl3_do_compress(sc, &wr)) {
753 SSLfatal(sc, SSL_AD_INTERNAL_ERROR, SSL_R_COMPRESSION_FAILURE);
754 return -1;
755 }
756 } else {
757 memcpy(SSL3_RECORD_get_data(&wr), SSL3_RECORD_get_input(&wr),
758 SSL3_RECORD_get_length(&wr));
759 SSL3_RECORD_reset_input(&wr);
760 }
761
762 /*
763 * we should still have the output to wr.data and the input from
764 * wr.input. Length should be wr.length. wr.data still points in the
765 * wb->buf
766 */
767
768 if (!SSL_WRITE_ETM(sc) && mac_size != 0) {
769 if (!s->method->ssl3_enc->mac(sc, &wr,
770 &(p[SSL3_RECORD_get_length(&wr) + eivlen]),
771 1)) {
772 SSLfatal(sc, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
773 return -1;
774 }
775 SSL3_RECORD_add_length(&wr, mac_size);
776 }
777
778 /* this is true regardless of mac size */
779 SSL3_RECORD_set_data(&wr, p);
780 SSL3_RECORD_reset_input(&wr);
781
782 if (eivlen)
783 SSL3_RECORD_add_length(&wr, eivlen);
784
785 if (s->method->ssl3_enc->enc(sc, &wr, 1, 1, NULL, mac_size) < 1) {
786 if (!ossl_statem_in_error(sc)) {
787 SSLfatal(sc, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
788 }
789 return -1;
790 }
791
792 if (SSL_WRITE_ETM(sc) && mac_size != 0) {
793 if (!s->method->ssl3_enc->mac(sc, &wr,
794 &(p[SSL3_RECORD_get_length(&wr)]), 1)) {
795 SSLfatal(sc, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
796 return -1;
797 }
798 SSL3_RECORD_add_length(&wr, mac_size);
799 }
800
801 /* record length after mac and block padding */
802
803 /* there's only one epoch between handshake and app data */
804
805 s2n(sc->rlayer.d->w_epoch, pseq);
806
807 memcpy(pseq, &(sc->rlayer.write_sequence[2]), 6);
808 pseq += 6;
809 s2n(SSL3_RECORD_get_length(&wr), pseq);
810
811 if (sc->msg_callback)
812 sc->msg_callback(1, 0, SSL3_RT_HEADER, pseq - DTLS1_RT_HEADER_LENGTH,
813 DTLS1_RT_HEADER_LENGTH, s, sc->msg_callback_arg);
814
815 /*
816 * we should now have wr.data pointing to the encrypted data, which is
817 * wr->length long
818 */
819 SSL3_RECORD_set_type(&wr, type); /* not needed but helps for debugging */
820 SSL3_RECORD_add_length(&wr, DTLS1_RT_HEADER_LENGTH);
821
822 ssl3_record_sequence_update(&(sc->rlayer.write_sequence[0]));
823
824 if (create_empty_fragment) {
825 /*
826 * we are in a recursive call; just return the length, don't write
827 * out anything here
828 */
829 *written = wr.length;
830 return 1;
831 }
832
833 /* now let's set up wb */
834 SSL3_BUFFER_set_left(wb, prefix_len + SSL3_RECORD_get_length(&wr));
835 SSL3_BUFFER_set_offset(wb, 0);
836
837 /*
838 * memorize arguments so that ssl3_write_pending can detect bad write
839 * retries later
840 */
841 sc->rlayer.wpend_tot = len;
842 sc->rlayer.wpend_buf = buf;
843 sc->rlayer.wpend_type = type;
844 sc->rlayer.wpend_ret = len;
845
846 /* we now just need to write the buffer. Calls SSLfatal() as required. */
847 return ssl3_write_pending(sc, type, buf, len, written);
848 }
849
dtls1_reset_seq_numbers(SSL_CONNECTION * s,int rw)850 void dtls1_reset_seq_numbers(SSL_CONNECTION *s, int rw)
851 {
852 unsigned char *seq;
853
854 if (rw & SSL3_CC_READ) {
855 s->rlayer.d->r_epoch++;
856
857 /*
858 * We must not use any buffered messages received from the previous
859 * epoch
860 */
861 dtls1_clear_received_buffer(s);
862 } else {
863 seq = s->rlayer.write_sequence;
864 memcpy(s->rlayer.d->last_write_sequence, seq,
865 sizeof(s->rlayer.write_sequence));
866 s->rlayer.d->w_epoch++;
867 memset(seq, 0, sizeof(s->rlayer.write_sequence));
868 }
869 }
870
