2 * Copyright 2018-2022 The OpenSSL Project Authors. All Rights Reserved.
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
10 #include "../../ssl_local.h"
11 #include "../record_local.h"
12 #include "recmethod_local.h"
14 /* mod 128 saturating subtract of two 64-bit values in big-endian order */
15 static int satsub64be(const unsigned char *v1, const unsigned char *v2)
25 /* We do not permit wrap-around */
26 if (l1 > l2 && ret < 0)
28 else if (l2 > l1 && ret > 0)
39 static int dtls_record_replay_check(OSSL_RECORD_LAYER *rl, DTLS_BITMAP *bitmap)
43 const unsigned char *seq = rl->sequence;
45 cmp = satsub64be(seq, bitmap->max_seq_num);
47 SSL3_RECORD_set_seq_num(&rl->rrec[0], seq);
48 return 1; /* this record in new */
51 if (shift >= sizeof(bitmap->map) * 8)
52 return 0; /* stale, outside the window */
53 else if (bitmap->map & ((uint64_t)1 << shift))
54 return 0; /* record previously received */
56 SSL3_RECORD_set_seq_num(&rl->rrec[0], seq);
60 static void dtls_record_bitmap_update(OSSL_RECORD_LAYER *rl,
65 const unsigned char *seq = rl->sequence;
67 cmp = satsub64be(seq, bitmap->max_seq_num);
70 if (shift < sizeof(bitmap->map) * 8)
71 bitmap->map <<= shift, bitmap->map |= 1UL;
74 memcpy(bitmap->max_seq_num, seq, SEQ_NUM_SIZE);
77 if (shift < sizeof(bitmap->map) * 8)
78 bitmap->map |= (uint64_t)1 << shift;
82 static DTLS_BITMAP *dtls_get_bitmap(OSSL_RECORD_LAYER *rl, SSL3_RECORD *rr,
83 unsigned int *is_next_epoch)
87 /* In current epoch, accept HM, CCS, DATA, & ALERT */
88 if (rr->epoch == rl->epoch)
92 * Only HM and ALERT messages can be from the next epoch and only if we
93 * have already processed all of the unprocessed records from the last
96 else if (rr->epoch == (unsigned long)(rl->epoch + 1)
97 && rl->unprocessed_rcds.epoch != rl->epoch
98 && (rr->type == SSL3_RT_HANDSHAKE || rr->type == SSL3_RT_ALERT)) {
100 return &rl->next_bitmap;
106 static void dtls_set_in_init(OSSL_RECORD_LAYER *rl, int in_init)
108 rl->in_init = in_init;
111 static int dtls_process_record(OSSL_RECORD_LAYER *rl, DTLS_BITMAP *bitmap)
118 unsigned char md[EVP_MAX_MD_SIZE];
119 SSL_MAC_BUF macbuf = { NULL, 0 };
125 * At this point, rl->packet_length == DTLS1_RT_HEADER_LENGTH + rr->length,
126 * and we have that many bytes in rl->packet
128 rr->input = &(rl->packet[DTLS1_RT_HEADER_LENGTH]);
131 * ok, we can now read from 'rl->packet' data into 'rr'. rr->input
132 * points at rr->length bytes, which need to be copied into rr->data by
133 * either the decryption or by the decompression. When the data is 'copied'
134 * into the rr->data buffer, rr->input will be pointed at the new buffer
138 * We now have - encrypted [ MAC [ compressed [ plain ] ] ] rr->length
139 * bytes of encrypted compressed stuff.
142 /* check is not needed I believe */
143 if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH) {
144 RLAYERfatal(rl, SSL_AD_RECORD_OVERFLOW, SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
148 /* decrypt in place in 'rr->input' */
149 rr->data = rr->input;
150 rr->orig_len = rr->length;
152 if (rl->md_ctx != NULL) {
153 const EVP_MD *tmpmd = EVP_MD_CTX_get0_md(rl->md_ctx);
156 imac_size = EVP_MD_get_size(tmpmd);
157 if (!ossl_assert(imac_size >= 0 && imac_size <= EVP_MAX_MD_SIZE)) {
158 RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_EVP_LIB);
161 mac_size = (size_t)imac_size;
165 if (rl->use_etm && rl->md_ctx != NULL) {
168 if (rr->orig_len < mac_size) {
169 RLAYERfatal(rl, SSL_AD_DECODE_ERROR, SSL_R_LENGTH_TOO_SHORT);
172 rr->length -= mac_size;
173 mac = rr->data + rr->length;
174 i = rl->funcs->mac(rl, rr, md, 0 /* not send */);
175 if (i == 0 || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0) {
176 RLAYERfatal(rl, SSL_AD_BAD_RECORD_MAC,
177 SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
181 * We've handled the mac now - there is no MAC inside the encrypted
188 * Set a mark around the packet decryption attempt. This is DTLS, so
189 * bad packets are just ignored, and we don't want to leave stray
190 * errors in the queue from processing bogus junk that we ignored.
193 enc_err = rl->funcs->cipher(rl, rr, 1, 0, &macbuf, mac_size);
197 * 0: if the record is publicly invalid, or an internal error, or AEAD
198 * decryption failed, or ETM decryption failed.
199 * 1: Success or MTE decryption failed (MAC will be randomised)
203 if (rl->alert != SSL_AD_NO_ALERT) {
204 /* RLAYERfatal() already called */
207 /* For DTLS we simply ignore bad packets. */
209 rl->packet_length = 0;
212 ERR_clear_last_mark();
213 OSSL_TRACE_BEGIN(TLS) {
214 BIO_printf(trc_out, "dec %zd\n", rr->length);
215 BIO_dump_indent(trc_out, rr->data, rr->length, 4);
216 } OSSL_TRACE_END(TLS);
218 /* r->length is now the compressed data plus mac */
220 && (rl->enc_ctx != NULL)
221 && (EVP_MD_CTX_get0_md(rl->md_ctx) != NULL)) {
222 /* rl->md_ctx != NULL => mac_size != -1 */
224 i = rl->funcs->mac(rl, rr, md, 0 /* not send */);
225 if (i == 0 || macbuf.mac == NULL
226 || CRYPTO_memcmp(md, macbuf.mac, mac_size) != 0)
228 if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH + mac_size)
233 /* decryption failed, silently discard message */
235 rl->packet_length = 0;
239 /* r->length is now just compressed */
240 if (rl->compctx != NULL) {
241 if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH) {
242 RLAYERfatal(rl, SSL_AD_RECORD_OVERFLOW,
243 SSL_R_COMPRESSED_LENGTH_TOO_LONG);
246 if (!tls_do_uncompress(rl, rr)) {
247 RLAYERfatal(rl, SSL_AD_DECOMPRESSION_FAILURE, SSL_R_BAD_DECOMPRESSION);
253 * Check if the received packet overflows the current Max Fragment
256 if (rr->length > rl->max_frag_len) {
257 RLAYERfatal(rl, SSL_AD_RECORD_OVERFLOW, SSL_R_DATA_LENGTH_TOO_LONG);
263 * So at this point the following is true
264 * ssl->s3.rrec.type is the type of record
265 * ssl->s3.rrec.length == number of bytes in record
266 * ssl->s3.rrec.off == offset to first valid byte
267 * ssl->s3.rrec.data == where to take bytes from, increment
271 /* we have pulled in a full packet so zero things */
272 rl->packet_length = 0;
274 /* Mark receipt of record. */
275 dtls_record_bitmap_update(rl, bitmap);
280 OPENSSL_free(macbuf.mac);
284 static int dtls_rlayer_buffer_record(OSSL_RECORD_LAYER *rl, record_pqueue *queue,
285 unsigned char *priority)
287 DTLS_RLAYER_RECORD_DATA *rdata;
290 /* Limit the size of the queue to prevent DOS attacks */
291 if (pqueue_size(queue->q) >= 100)
294 rdata = OPENSSL_malloc(sizeof(*rdata));
295 item = pitem_new(priority, rdata);
296 if (rdata == NULL || item == NULL) {
299 RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
303 rdata->packet = rl->packet;
304 rdata->packet_length = rl->packet_length;
305 memcpy(&(rdata->rbuf), &rl->rbuf, sizeof(SSL3_BUFFER));
306 memcpy(&(rdata->rrec), &rl->rrec[0], sizeof(SSL3_RECORD));
311 rl->packet_length = 0;
312 memset(&rl->rbuf, 0, sizeof(SSL3_BUFFER));
313 memset(&rl->rrec[0], 0, sizeof(rl->rrec[0]));
315 if (!tls_setup_read_buffer(rl)) {
316 /* RLAYERfatal() already called */
317 OPENSSL_free(rdata->rbuf.buf);
323 if (pqueue_insert(queue->q, item) == NULL) {
324 /* Must be a duplicate so ignore it */
325 OPENSSL_free(rdata->rbuf.buf);
333 /* copy buffered record into OSSL_RECORD_LAYER structure */
334 static int dtls_copy_rlayer_record(OSSL_RECORD_LAYER *rl, pitem *item)
336 DTLS_RLAYER_RECORD_DATA *rdata;
338 rdata = (DTLS_RLAYER_RECORD_DATA *)item->data;
340 SSL3_BUFFER_release(&rl->rbuf);
342 rl->packet = rdata->packet;
343 rl->packet_length = rdata->packet_length;
344 memcpy(&rl->rbuf, &(rdata->rbuf), sizeof(SSL3_BUFFER));
345 memcpy(&rl->rrec[0], &(rdata->rrec), sizeof(SSL3_RECORD));
347 /* Set proper sequence number for mac calculation */
348 memcpy(&(rl->sequence[2]), &(rdata->packet[5]), 6);
353 static int dtls_retrieve_rlayer_buffered_record(OSSL_RECORD_LAYER *rl,
354 record_pqueue *queue)
358 item = pqueue_pop(queue->q);
360 dtls_copy_rlayer_record(rl, item);
362 OPENSSL_free(item->data);
372 * Call this to get a new input record.
373 * It will return <= 0 if more data is needed, normally due to an error
374 * or non-blocking IO.
375 * When it finishes, one packet has been decoded and can be found in
376 * ssl->s3.rrec.type - is the type of record
377 * ssl->s3.rrec.data - data
378 * ssl->s3.rrec.length - number of bytes
380 int dtls_get_more_records(OSSL_RECORD_LAYER *rl)
382 int ssl_major, ssl_minor;
386 unsigned char *p = NULL;
387 unsigned short version;
389 unsigned int is_next_epoch;
393 rl->num_released = 0;
397 if (rl->rbuf.buf == NULL) {
398 if (!tls_setup_read_buffer(rl)) {
399 /* RLAYERfatal() already called */
400 return OSSL_RECORD_RETURN_FATAL;
405 /* if we're renegotiating, then there may be buffered records */
406 if (dtls_retrieve_rlayer_buffered_record(rl, &rl->processed_rcds)) {
408 return OSSL_RECORD_RETURN_SUCCESS;
411 /* get something from the wire */
413 /* check if we have the header */
414 if ((rl->rstate != SSL_ST_READ_BODY) ||
415 (rl->packet_length < DTLS1_RT_HEADER_LENGTH)) {
416 rret = rl->funcs->read_n(rl, DTLS1_RT_HEADER_LENGTH,
417 SSL3_BUFFER_get_len(&rl->rbuf), 0, 1, &n);
418 /* read timeout is handled by dtls1_read_bytes */
419 if (rret < OSSL_RECORD_RETURN_SUCCESS) {
420 /* RLAYERfatal() already called if appropriate */
421 return rret; /* error or non-blocking */
424 /* this packet contained a partial record, dump it */
425 if (rl->packet_length != DTLS1_RT_HEADER_LENGTH) {
426 rl->packet_length = 0;
430 rl->rstate = SSL_ST_READ_BODY;
434 if (rl->msg_callback != NULL)
435 rl->msg_callback(0, 0, SSL3_RT_HEADER, p, DTLS1_RT_HEADER_LENGTH,
438 /* Pull apart the header into the DTLS1_RECORD */
442 version = (ssl_major << 8) | ssl_minor;
444 /* sequence number is 64 bits, with top 2 bytes = epoch */
447 memcpy(&(rl->sequence[2]), p, 6);
453 * Lets check the version. We tolerate alerts that don't have the exact
454 * version number (e.g. because of protocol version errors)
456 if (!rl->is_first_record && rr->type != SSL3_RT_ALERT) {
457 if (version != rl->version) {
458 /* unexpected version, silently discard */
460 rl->packet_length = 0;
466 (rl->version == DTLS_ANY_VERSION ? DTLS1_VERSION_MAJOR
467 : rl->version >> 8)) {
468 /* wrong version, silently discard record */
470 rl->packet_length = 0;
474 if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH) {
475 /* record too long, silently discard it */
477 rl->packet_length = 0;
482 * If received packet overflows maximum possible fragment length then
483 * silently discard it
485 if (rr->length > rl->max_frag_len + SSL3_RT_MAX_ENCRYPTED_OVERHEAD) {
486 /* record too long, silently discard it */
488 rl->packet_length = 0;
492 /* now rl->rstate == SSL_ST_READ_BODY */
495 /* rl->rstate == SSL_ST_READ_BODY, get and decode the data */
497 if (rr->length > rl->packet_length - DTLS1_RT_HEADER_LENGTH) {
498 /* now rl->packet_length == DTLS1_RT_HEADER_LENGTH */
500 rret = rl->funcs->read_n(rl, more, more, 1, 1, &n);
501 /* this packet contained a partial record, dump it */
502 if (rret < OSSL_RECORD_RETURN_SUCCESS || n != more) {
503 if (rl->alert != SSL_AD_NO_ALERT) {
504 /* read_n() called RLAYERfatal() */
505 return OSSL_RECORD_RETURN_FATAL;
508 rl->packet_length = 0;
513 * now n == rr->length,
514 * and rl->packet_length == DTLS1_RT_HEADER_LENGTH + rr->length
517 /* set state for later operations */
518 rl->rstate = SSL_ST_READ_HEADER;
520 /* match epochs. NULL means the packet is dropped on the floor */
521 bitmap = dtls_get_bitmap(rl, rr, &is_next_epoch);
522 if (bitmap == NULL) {
524 rl->packet_length = 0; /* dump this record */
525 goto again; /* get another record */
527 #ifndef OPENSSL_NO_SCTP
528 /* Only do replay check if no SCTP bio */
529 if (!BIO_dgram_is_sctp(rl->bio)) {
531 /* Check whether this is a repeat, or aged record. */
532 if (!dtls_record_replay_check(rl, bitmap)) {
534 rl->packet_length = 0; /* dump this record */
535 goto again; /* get another record */
537 #ifndef OPENSSL_NO_SCTP
541 /* just read a 0 length packet */
546 * If this record is from the next epoch (either HM or ALERT), and a
547 * handshake is currently in progress, buffer it since it cannot be
548 * processed at this time.
552 if (dtls_rlayer_buffer_record(rl, &(rl->unprocessed_rcds),
554 /* RLAYERfatal() already called */
555 return OSSL_RECORD_RETURN_FATAL;
559 rl->packet_length = 0;
563 if (!dtls_process_record(rl, bitmap)) {
564 if (rl->alert != SSL_AD_NO_ALERT) {
565 /* dtls_process_record() called RLAYERfatal */
566 return OSSL_RECORD_RETURN_FATAL;
569 rl->packet_length = 0; /* dump this record */
570 goto again; /* get another record */
574 return OSSL_RECORD_RETURN_SUCCESS;
577 static int dtls_free(OSSL_RECORD_LAYER *rl)
580 size_t left, written;
582 DTLS_RLAYER_RECORD_DATA *rdata;
590 * This record layer is closing but we still have data left in our
591 * buffer. It must be destined for the next epoch - so push it there.
593 ret = BIO_write_ex(rl->next, rbuf->buf + rbuf->offset, left, &written);
597 if (rl->unprocessed_rcds.q != NULL) {
598 while ((item = pqueue_pop(rl->unprocessed_rcds.q)) != NULL) {
599 rdata = (DTLS_RLAYER_RECORD_DATA *)item->data;
600 /* Push to the next record layer */
601 ret &= BIO_write_ex(rl->next, rdata->packet, rdata->packet_length,
603 OPENSSL_free(rdata->rbuf.buf);
604 OPENSSL_free(item->data);
607 pqueue_free(rl->unprocessed_rcds.q);
610 if (rl->processed_rcds.q != NULL) {
611 while ((item = pqueue_pop(rl->processed_rcds.q)) != NULL) {
612 rdata = (DTLS_RLAYER_RECORD_DATA *)item->data;
613 OPENSSL_free(rdata->rbuf.buf);
614 OPENSSL_free(item->data);
617 pqueue_free(rl->processed_rcds.q);
620 return tls_free(rl) && ret;
624 dtls_new_record_layer(OSSL_LIB_CTX *libctx, const char *propq, int vers,
625 int role, int direction, int level, uint16_t epoch,
626 unsigned char *key, size_t keylen, unsigned char *iv,
627 size_t ivlen, unsigned char *mackey, size_t mackeylen,
628 const EVP_CIPHER *ciph, size_t taglen,
630 const EVP_MD *md, COMP_METHOD *comp, BIO *prev,
631 BIO *transport, BIO *next, BIO_ADDR *local, BIO_ADDR *peer,
632 const OSSL_PARAM *settings, const OSSL_PARAM *options,
633 const OSSL_DISPATCH *fns, void *cbarg,
634 OSSL_RECORD_LAYER **retrl)
638 ret = tls_int_new_record_layer(libctx, propq, vers, role, direction, level,
639 key, keylen, iv, ivlen, mackey, mackeylen,
640 ciph, taglen, mactype, md, comp, prev,
641 transport, next, local, peer, settings,
642 options, fns, cbarg, retrl);
644 if (ret != OSSL_RECORD_RETURN_SUCCESS)
647 (*retrl)->unprocessed_rcds.q = pqueue_new();
648 (*retrl)->processed_rcds.q = pqueue_new();
649 if ((*retrl)->unprocessed_rcds.q == NULL
650 || (*retrl)->processed_rcds.q == NULL) {
653 ERR_raise(ERR_LIB_SSL, ERR_R_SSL_LIB);
654 return OSSL_RECORD_RETURN_FATAL;
657 (*retrl)->unprocessed_rcds.epoch = epoch + 1;
658 (*retrl)->processed_rcds.epoch = epoch;
660 (*retrl)->isdtls = 1;
661 (*retrl)->epoch = epoch;
662 (*retrl)->in_init = 1;
665 case DTLS_ANY_VERSION:
666 (*retrl)->funcs = &dtls_any_funcs;
668 case DTLS1_2_VERSION:
671 (*retrl)->funcs = &dtls_1_funcs;
674 /* Should not happen */
675 ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR);
676 ret = OSSL_RECORD_RETURN_FATAL;
680 ret = (*retrl)->funcs->set_crypto_state(*retrl, level, key, keylen, iv,
681 ivlen, mackey, mackeylen, ciph,
682 taglen, mactype, md, comp);
685 if (ret != OSSL_RECORD_RETURN_SUCCESS) {
686 OPENSSL_free(*retrl);
692 int dtls_prepare_record_header(OSSL_RECORD_LAYER *rl,
694 OSSL_RECORD_TEMPLATE *templ,
695 unsigned int rectype,
696 unsigned char **recdata)
702 maxcomplen = templ->buflen;
703 if (rl->compctx != NULL)
704 maxcomplen += SSL3_RT_MAX_COMPRESSED_OVERHEAD;
706 if (!WPACKET_put_bytes_u8(thispkt, rectype)
707 || !WPACKET_put_bytes_u16(thispkt, templ->version)
708 || !WPACKET_put_bytes_u16(thispkt, rl->epoch)
709 || !WPACKET_memcpy(thispkt, &(rl->sequence[2]), 6)
710 || !WPACKET_start_sub_packet_u16(thispkt)
712 && !WPACKET_allocate_bytes(thispkt, rl->eivlen, NULL))
714 && !WPACKET_reserve_bytes(thispkt, maxcomplen,
716 RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
723 int dtls_write_records(OSSL_RECORD_LAYER *rl, OSSL_RECORD_TEMPLATE *templates,
729 WPACKET pkt, *thispkt = &pkt;
732 unsigned char *compressdata = NULL;
734 if (rl->md_ctx != NULL && EVP_MD_CTX_get0_md(rl->md_ctx) != NULL) {
735 mac_size = EVP_MD_CTX_get_size(rl->md_ctx);
737 RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
743 /* Should not happen */
744 RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
748 if (!rl->funcs->allocate_write_buffers(rl, templates, numtempl, NULL)) {
749 /* RLAYERfatal() already called */
753 if (!rl->funcs->initialise_write_packets(rl, templates, numtempl,
754 NULL, thispkt, rl->wbuf,
756 /* RLAYERfatal() already called */
762 SSL3_RECORD_set_type(&wr, templates->type);
763 SSL3_RECORD_set_rec_version(&wr, templates->version);
765 if (!rl->funcs->prepare_record_header(rl, thispkt, templates,
766 templates->type, &compressdata)) {
767 /* RLAYERfatal() already called */
771 /* lets setup the record stuff. */
772 SSL3_RECORD_set_data(&wr, compressdata);
773 SSL3_RECORD_set_length(&wr, templates->buflen);
774 SSL3_RECORD_set_input(&wr, (unsigned char *)templates->buf);
777 * we now 'read' from wr.input, wr.length bytes into wr.data
780 /* first we compress */
781 if (rl->compctx != NULL) {
782 if (!tls_do_compress(rl, &wr)
783 || !WPACKET_allocate_bytes(thispkt, wr.length, NULL)) {
784 RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, SSL_R_COMPRESSION_FAILURE);
787 } else if (compressdata != NULL) {
788 if (!WPACKET_memcpy(thispkt, wr.input, wr.length)) {
789 RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
792 SSL3_RECORD_reset_input(&wr);
795 if (!rl->funcs->prepare_for_encryption(rl, mac_size, thispkt, &wr)) {
796 /* RLAYERfatal() already called */
800 if (rl->funcs->cipher(rl, &wr, 1, 1, NULL, mac_size) < 1) {
801 if (rl->alert == SSL_AD_NO_ALERT) {
802 RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
807 if (!rl->funcs->post_encryption_processing(rl, mac_size, templates,
809 /* RLAYERfatal() already called */
813 /* TODO(RECLAYER): FIXME */
814 ssl3_record_sequence_update(rl->sequence);
816 /* now let's set up wb */
817 SSL3_BUFFER_set_left(wb, SSL3_RECORD_get_length(&wr));
822 WPACKET_cleanup(thispkt);
826 static size_t dtls_get_max_record_overhead(OSSL_RECORD_LAYER *rl)
828 size_t blocksize, mac_size;
831 * TODO(RECLAYER): Review this. This is what the existing code did.
832 * I suspect it's not quite right. What about IV? AEAD Tag? Compression
835 if (rl->md_ctx != NULL) {
836 if (rl->enc_ctx != NULL
837 && (EVP_CIPHER_get_flags(EVP_CIPHER_CTX_get0_cipher(rl->enc_ctx)) &
838 EVP_CIPH_FLAG_AEAD_CIPHER) != 0)
841 mac_size = EVP_MD_CTX_get_size(rl->md_ctx);
846 if (rl->enc_ctx != NULL &&
847 (EVP_CIPHER_CTX_get_mode(rl->enc_ctx) == EVP_CIPH_CBC_MODE))
848 blocksize = 2 * EVP_CIPHER_CTX_get_block_size(rl->enc_ctx);
852 return DTLS1_RT_HEADER_LENGTH + mac_size + blocksize;
855 const OSSL_RECORD_METHOD ossl_dtls_record_method = {
856 dtls_new_record_layer,
859 tls_unprocessed_read_pending,
860 tls_processed_read_pending,
861 tls_app_data_pending,
863 tls_get_max_record_len,
866 tls_retry_write_records,
871 tls_set_protocol_version,
873 tls_set_first_handshake,
874 tls_set_max_pipelines,
879 tls_set_max_frag_len,
880 dtls_get_max_record_overhead