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
, DTLS1_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
& (1UL << 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
|= 1UL << shift
;
82 static DTLS1_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
, DTLS1_BITMAP
*bitmap
)
118 unsigned char md
[EVP_MAX_MD_SIZE
];
119 SSL_MAC_BUF macbuf
= { NULL
, 0 };
125 * At this point, rl->packet_length == SSL3_RT_HEADER_LNGTH + 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
) {
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
!= 0) {
204 /* SSLfatal() got 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
->expand
!= 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 (rl
->max_frag_len
> 0 && rr
->length
> rl
->max_frag_len
) {
257 RLAYERfatal(rl
, SSL_AD_RECORD_OVERFLOW
, SSL_R_DATA_LENGTH_TOO_LONG
);
264 * So at this point the following is true
265 * ssl->s3.rrec.type is the type of record
266 * ssl->s3.rrec.length == number of bytes in record
267 * ssl->s3.rrec.off == offset to first valid byte
268 * ssl->s3.rrec.data == where to take bytes from, increment
272 /* we have pulled in a full packet so zero things */
273 rl
->packet_length
= 0;
275 /* Mark receipt of record. */
276 dtls_record_bitmap_update(rl
, bitmap
);
281 OPENSSL_free(macbuf
.mac
);
285 static int dtls_rlayer_buffer_record(OSSL_RECORD_LAYER
*rl
, record_pqueue
*queue
,
286 unsigned char *priority
)
288 DTLS_RLAYER_RECORD_DATA
*rdata
;
291 /* Limit the size of the queue to prevent DOS attacks */
292 if (pqueue_size(queue
->q
) >= 100)
295 rdata
= OPENSSL_malloc(sizeof(*rdata
));
296 item
= pitem_new(priority
, rdata
);
297 if (rdata
== NULL
|| item
== NULL
) {
300 RLAYERfatal(rl
, SSL_AD_INTERNAL_ERROR
, ERR_R_INTERNAL_ERROR
);
304 rdata
->packet
= rl
->packet
;
305 rdata
->packet_length
= rl
->packet_length
;
306 memcpy(&(rdata
->rbuf
), &rl
->rbuf
, sizeof(SSL3_BUFFER
));
307 memcpy(&(rdata
->rrec
), &rl
->rrec
[0], sizeof(SSL3_RECORD
));
312 rl
->packet_length
= 0;
313 memset(&rl
->rbuf
, 0, sizeof(SSL3_BUFFER
));
314 memset(&rl
->rrec
[0], 0, sizeof(rl
->rrec
[0]));
317 if (!rlayer_setup_read_buffer(rl
)) {
318 /* SSLfatal() already called */
319 OPENSSL_free(rdata
->rbuf
.buf
);
325 if (pqueue_insert(queue
->q
, item
) == NULL
) {
326 /* Must be a duplicate so ignore it */
327 OPENSSL_free(rdata
->rbuf
.buf
);
335 /* copy buffered record into OSSL_RECORD_LAYER structure */
336 static int dtls_copy_rlayer_record(OSSL_RECORD_LAYER
*rl
, pitem
*item
)
338 DTLS_RLAYER_RECORD_DATA
*rdata
;
340 rdata
= (DTLS_RLAYER_RECORD_DATA
*)item
->data
;
342 SSL3_BUFFER_release(&rl
->rbuf
);
344 rl
->packet
= rdata
->packet
;
345 rl
->packet_length
= rdata
->packet_length
;
346 memcpy(&rl
->rbuf
, &(rdata
->rbuf
), sizeof(SSL3_BUFFER
));
347 memcpy(&rl
->rrec
[0], &(rdata
->rrec
), sizeof(SSL3_RECORD
));
349 /* Set proper sequence number for mac calculation */
350 memcpy(&(rl
->sequence
[2]), &(rdata
->packet
[5]), 6);
355 static int dtls_retrieve_rlayer_buffered_record(OSSL_RECORD_LAYER
*rl
,
356 record_pqueue
*queue
)
360 item
= pqueue_pop(queue
->q
);
362 dtls_copy_rlayer_record(rl
, item
);
364 OPENSSL_free(item
->data
);
374 * Call this to get a new input record.
375 * It will return <= 0 if more data is needed, normally due to an error
376 * or non-blocking IO.
377 * When it finishes, one packet has been decoded and can be found in
378 * ssl->s3.rrec.type - is the type of record
379 * ssl->s3.rrec.data - data
380 * ssl->s3.rrec.length - number of bytes
382 int dtls_get_more_records(OSSL_RECORD_LAYER
*rl
)
384 int ssl_major
, ssl_minor
;
388 unsigned char *p
= NULL
;
389 unsigned short version
;
390 DTLS1_BITMAP
*bitmap
;
391 unsigned int is_next_epoch
;
395 rl
->num_released
= 0;
399 if (rl
->rbuf
.buf
== NULL
) {
400 if (!rlayer_setup_read_buffer(rl
)) {
401 /* RLAYERfatal() already called */
402 return OSSL_RECORD_RETURN_FATAL
;
407 /* if we're renegotiating, then there may be buffered records */
408 if (dtls_retrieve_rlayer_buffered_record(rl
, &rl
->processed_rcds
)) {
410 return OSSL_RECORD_RETURN_SUCCESS
;
413 /* get something from the wire */
415 /* check if we have the header */
416 if ((rl
->rstate
!= SSL_ST_READ_BODY
) ||
417 (rl
->packet_length
< DTLS1_RT_HEADER_LENGTH
)) {
418 rret
= rl
->funcs
->read_n(rl
, DTLS1_RT_HEADER_LENGTH
,
419 SSL3_BUFFER_get_len(&rl
->rbuf
), 0, 1, &n
);
420 /* read timeout is handled by dtls1_read_bytes */
421 if (rret
< OSSL_RECORD_RETURN_SUCCESS
) {
422 /* SSLfatal() already called if appropriate */
423 return rret
; /* error or non-blocking */
426 /* this packet contained a partial record, dump it */
427 if (rl
->packet_length
!= DTLS1_RT_HEADER_LENGTH
) {
428 rl
->packet_length
= 0;
432 rl
->rstate
= SSL_ST_READ_BODY
;
436 rl
->msg_callback(0, 0, SSL3_RT_HEADER
, p
, DTLS1_RT_HEADER_LENGTH
,
439 /* Pull apart the header into the DTLS1_RECORD */
443 version
= (ssl_major
<< 8) | ssl_minor
;
445 /* sequence number is 64 bits, with top 2 bytes = epoch */
448 memcpy(&(rl
->sequence
[2]), p
, 6);
455 * Lets check the version. We tolerate alerts that don't have the exact
456 * version number (e.g. because of protocol version errors)
458 if (!rl
->is_first_record
&& rr
->type
!= SSL3_RT_ALERT
) {
459 if (version
!= rl
->version
) {
460 /* unexpected version, silently discard */
463 rl
->packet_length
= 0;
470 (rl
->version
== DTLS_ANY_VERSION
? DTLS1_VERSION_MAJOR
471 : rl
->version
>> 8)) {
472 /* wrong version, silently discard record */
475 rl
->packet_length
= 0;
479 if (rr
->length
> SSL3_RT_MAX_ENCRYPTED_LENGTH
) {
480 /* record too long, silently discard it */
483 rl
->packet_length
= 0;
489 * If received packet overflows maximum possible fragment length then
490 * silently discard it
492 if (rl
->max_frag_len
> 0
493 && rr
->length
> rl
->max_frag_len
+ SSL3_RT_MAX_ENCRYPTED_OVERHEAD
) {
494 /* record too long, silently discard it */
497 rl
->packet_length
= 0;
501 /* now rl->rstate == SSL_ST_READ_BODY */
504 /* rl->rstate == SSL_ST_READ_BODY, get and decode the data */
507 rl
->packet_length
- DTLS1_RT_HEADER_LENGTH
) {
508 /* now rl->packet_length == DTLS1_RT_HEADER_LENGTH */
510 rret
= rl
->funcs
->read_n(rl
, more
, more
, 1, 1, &n
);
511 /* this packet contained a partial record, dump it */
512 if (rret
< OSSL_RECORD_RETURN_SUCCESS
|| n
!= more
) {
513 if (rl
->alert
!= 0) {
514 /* read_n() called RLAYERfatal() */
515 return OSSL_RECORD_RETURN_FATAL
;
519 rl
->packet_length
= 0;
524 * now n == rr->length,
525 * and rl->packet_length == DTLS1_RT_HEADER_LENGTH + rr->length
528 /* set state for later operations */
529 rl
->rstate
= SSL_ST_READ_HEADER
;
531 /* match epochs. NULL means the packet is dropped on the floor */
532 bitmap
= dtls_get_bitmap(rl
, rr
, &is_next_epoch
);
533 if (bitmap
== NULL
) {
535 rl
->packet_length
= 0; /* dump this record */
536 goto again
; /* get another record */
538 #ifndef OPENSSL_NO_SCTP
539 /* Only do replay check if no SCTP bio */
540 if (!BIO_dgram_is_sctp(rl
->bio
)) {
542 /* Check whether this is a repeat, or aged record. */
543 if (!dtls_record_replay_check(rl
, bitmap
)) {
546 rl
->packet_length
= 0; /* dump this record */
547 goto again
; /* get another record */
549 #ifndef OPENSSL_NO_SCTP
553 /* just read a 0 length packet */
554 if (rr
->length
== 0) {
560 * If this record is from the next epoch (either HM or ALERT), and a
561 * handshake is currently in progress, buffer it since it cannot be
562 * processed at this time.
566 if (dtls_rlayer_buffer_record(rl
,
567 &(rl
->unprocessed_rcds
),
569 /* SSLfatal() already called */
570 return OSSL_RECORD_RETURN_FATAL
;
575 rl
->packet_length
= 0;
579 if (!dtls_process_record(rl
, bitmap
)) {
580 if (rl
->alert
!= 0) {
581 /* dtls_process_record() called RLAYERfatal */
582 return OSSL_RECORD_RETURN_FATAL
;
586 rl
->packet_length
= 0; /* dump this record */
587 goto again
; /* get another record */
591 return OSSL_RECORD_RETURN_SUCCESS
;
595 static int dtls_free(OSSL_RECORD_LAYER
*rl
)
598 size_t left
, written
;
600 DTLS_RLAYER_RECORD_DATA
*rdata
;
608 * This record layer is closing but we still have data left in our
609 * buffer. It must be destined for the next epoch - so push it there.
611 ret
= BIO_write_ex(rl
->next
, rbuf
->buf
+ rbuf
->offset
, left
, &written
);
615 if (rl
->unprocessed_rcds
.q
!= NULL
) {
616 while ((item
= pqueue_pop(rl
->unprocessed_rcds
.q
)) != NULL
) {
617 rdata
= (DTLS_RLAYER_RECORD_DATA
*)item
->data
;
618 /* Push to the next record layer */
619 /* TODO(RECLAYER): Handle SCTP meta data */
620 ret
&= BIO_write_ex(rl
->next
, rdata
->packet
, rdata
->packet_length
,
622 OPENSSL_free(rdata
->rbuf
.buf
);
623 OPENSSL_free(item
->data
);
626 pqueue_free(rl
->unprocessed_rcds
.q
);
629 if (rl
->processed_rcds
.q
!= NULL
) {
630 while ((item
= pqueue_pop(rl
->processed_rcds
.q
)) != NULL
) {
631 rdata
= (DTLS_RLAYER_RECORD_DATA
*)item
->data
;
632 OPENSSL_free(rdata
->rbuf
.buf
);
633 OPENSSL_free(item
->data
);
636 pqueue_free(rl
->processed_rcds
.q
);
639 return tls_free(rl
) && ret
;
643 dtls_new_record_layer(OSSL_LIB_CTX
*libctx
, const char *propq
, int vers
,
644 int role
, int direction
, int level
, unsigned int epoch
,
645 unsigned char *key
, size_t keylen
, unsigned char *iv
,
646 size_t ivlen
, unsigned char *mackey
, size_t mackeylen
,
647 const EVP_CIPHER
*ciph
, size_t taglen
,
648 /* TODO(RECLAYER): This probably should not be an int */
650 const EVP_MD
*md
, const SSL_COMP
*comp
, BIO
*prev
,
651 BIO
*transport
, BIO
*next
, BIO_ADDR
*local
, BIO_ADDR
*peer
,
652 const OSSL_PARAM
*settings
, const OSSL_PARAM
*options
,
653 const OSSL_DISPATCH
*fns
, void *cbarg
,
654 OSSL_RECORD_LAYER
**retrl
)
659 ret
= tls_int_new_record_layer(libctx
, propq
, vers
, role
, direction
, level
,
660 key
, keylen
, iv
, ivlen
, mackey
, mackeylen
,
661 ciph
, taglen
, mactype
, md
, comp
, prev
,
662 transport
, next
, local
, peer
, settings
,
663 options
, fns
, cbarg
, retrl
);
665 if (ret
!= OSSL_RECORD_RETURN_SUCCESS
)
668 (*retrl
)->unprocessed_rcds
.q
= pqueue_new();
669 (*retrl
)->processed_rcds
.q
= pqueue_new();
670 if ((*retrl
)->unprocessed_rcds
.q
== NULL
|| (*retrl
)->processed_rcds
.q
== NULL
) {
673 RLAYERfatal(*retrl
, SSL_AD_INTERNAL_ERROR
, ERR_R_MALLOC_FAILURE
);
674 return OSSL_RECORD_RETURN_FATAL
;
677 (*retrl
)->unprocessed_rcds
.epoch
= epoch
+ 1;
678 (*retrl
)->processed_rcds
.epoch
= epoch
;
680 (*retrl
)->isdtls
= 1;
681 (*retrl
)->epoch
= epoch
;
682 (*retrl
)->in_init
= 1;
685 case DTLS_ANY_VERSION
:
686 (*retrl
)->funcs
= &dtls_any_funcs
;
688 case DTLS1_2_VERSION
:
691 (*retrl
)->funcs
= &dtls_1_funcs
;
694 /* Should not happen */
695 ERR_raise(ERR_LIB_SSL
, ERR_R_INTERNAL_ERROR
);
696 ret
= OSSL_RECORD_RETURN_FATAL
;
700 ret
= (*retrl
)->funcs
->set_crypto_state(*retrl
, level
, key
, keylen
, iv
,
701 ivlen
, mackey
, mackeylen
, ciph
,
702 taglen
, mactype
, md
, comp
);
705 if (ret
!= OSSL_RECORD_RETURN_SUCCESS
) {
706 OPENSSL_free(*retrl
);
712 const OSSL_RECORD_METHOD ossl_dtls_record_method
= {
713 dtls_new_record_layer
,
716 tls_unprocessed_read_pending
,
717 tls_processed_read_pending
,
718 tls_app_data_pending
,
720 tls_get_max_record_len
,
723 tls_retry_write_records
,
728 tls_set_protocol_version
,
730 tls_set_first_handshake
,
731 tls_set_max_pipelines
,