2 * Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (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_locl.h"
11 #include "internal/constant_time_locl.h"
12 #include <openssl/rand.h>
13 #include "record_locl.h"
14 #include "internal/cryptlib.h"
16 static const unsigned char ssl3_pad_1
[48] = {
17 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36,
18 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36,
19 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36,
20 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36,
21 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36,
22 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36
25 static const unsigned char ssl3_pad_2
[48] = {
26 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c,
27 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c,
28 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c,
29 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c,
30 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c,
31 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c
35 * Clear the contents of an SSL3_RECORD but retain any memory allocated
37 void SSL3_RECORD_clear(SSL3_RECORD
*r
, size_t num_recs
)
42 for (i
= 0; i
< num_recs
; i
++) {
45 memset(&r
[i
], 0, sizeof(*r
));
50 void SSL3_RECORD_release(SSL3_RECORD
*r
, size_t num_recs
)
54 for (i
= 0; i
< num_recs
; i
++) {
55 OPENSSL_free(r
[i
].comp
);
60 void SSL3_RECORD_set_seq_num(SSL3_RECORD
*r
, const unsigned char *seq_num
)
62 memcpy(r
->seq_num
, seq_num
, SEQ_NUM_SIZE
);
66 * Peeks ahead into "read_ahead" data to see if we have a whole record waiting
67 * for us in the buffer.
69 static int ssl3_record_app_data_waiting(SSL
*s
)
75 rbuf
= RECORD_LAYER_get_rbuf(&s
->rlayer
);
77 p
= SSL3_BUFFER_get_buf(rbuf
);
81 left
= SSL3_BUFFER_get_left(rbuf
);
83 if (left
< SSL3_RT_HEADER_LENGTH
)
86 p
+= SSL3_BUFFER_get_offset(rbuf
);
89 * We only check the type and record length, we will sanity check version
92 if (*p
!= SSL3_RT_APPLICATION_DATA
)
98 if (left
< SSL3_RT_HEADER_LENGTH
+ len
)
104 int early_data_count_ok(SSL
*s
, size_t length
, size_t overhead
, int *al
)
106 uint32_t max_early_data
= s
->max_early_data
;
107 SSL_SESSION
*sess
= s
->session
;
110 * If we are a client then we always use the max_early_data from the
111 * session/psksession. Otherwise we go with the lowest out of the max early
112 * data set in the session and the configured max_early_data.
114 if (!s
->server
&& sess
->ext
.max_early_data
== 0) {
115 if (!ossl_assert(s
->psksession
!= NULL
116 && s
->psksession
->ext
.max_early_data
> 0)) {
117 SSLerr(SSL_F_EARLY_DATA_COUNT_OK
, ERR_R_INTERNAL_ERROR
);
120 sess
= s
->psksession
;
123 || (s
->hit
&& sess
->ext
.max_early_data
< s
->max_early_data
))
124 max_early_data
= sess
->ext
.max_early_data
;
126 if (max_early_data
== 0) {
128 *al
= SSL_AD_UNEXPECTED_MESSAGE
;
129 SSLerr(SSL_F_EARLY_DATA_COUNT_OK
, SSL_R_TOO_MUCH_EARLY_DATA
);
133 /* If we are dealing with ciphertext we need to allow for the overhead */
134 max_early_data
+= overhead
;
136 if (s
->early_data_count
+ length
> max_early_data
) {
138 *al
= SSL_AD_UNEXPECTED_MESSAGE
;
139 SSLerr(SSL_F_EARLY_DATA_COUNT_OK
, SSL_R_TOO_MUCH_EARLY_DATA
);
142 s
->early_data_count
+= length
;
148 * MAX_EMPTY_RECORDS defines the number of consecutive, empty records that
149 * will be processed per call to ssl3_get_record. Without this limit an
150 * attacker could send empty records at a faster rate than we can process and
151 * cause ssl3_get_record to loop forever.
153 #define MAX_EMPTY_RECORDS 32
155 #define SSL2_RT_HEADER_LENGTH 2
157 * Call this to get new input records.
158 * It will return <= 0 if more data is needed, normally due to an error
159 * or non-blocking IO.
160 * When it finishes, |numrpipes| records have been decoded. For each record 'i':
161 * rr[i].type - is the type of record
163 * rr[i].length, - number of bytes
164 * Multiple records will only be returned if the record types are all
165 * SSL3_RT_APPLICATION_DATA. The number of records returned will always be <=
168 /* used only by ssl3_read_bytes */
169 int ssl3_get_record(SSL
*s
)
172 int enc_err
, rret
, ret
= -1;
175 SSL3_RECORD
*rr
, *thisrr
;
179 unsigned char md
[EVP_MAX_MD_SIZE
];
180 unsigned int version
;
183 size_t num_recs
= 0, max_recs
, j
;
184 PACKET pkt
, sslv2pkt
;
185 size_t first_rec_len
;
187 rr
= RECORD_LAYER_get_rrec(&s
->rlayer
);
188 rbuf
= RECORD_LAYER_get_rbuf(&s
->rlayer
);
189 max_recs
= s
->max_pipelines
;
195 thisrr
= &rr
[num_recs
];
197 /* check if we have the header */
198 if ((RECORD_LAYER_get_rstate(&s
->rlayer
) != SSL_ST_READ_BODY
) ||
199 (RECORD_LAYER_get_packet_length(&s
->rlayer
)
200 < SSL3_RT_HEADER_LENGTH
)) {
204 rret
= ssl3_read_n(s
, SSL3_RT_HEADER_LENGTH
,
205 SSL3_BUFFER_get_len(rbuf
), 0,
206 num_recs
== 0 ? 1 : 0, &n
);
208 return rret
; /* error or non-blocking */
209 RECORD_LAYER_set_rstate(&s
->rlayer
, SSL_ST_READ_BODY
);
211 p
= RECORD_LAYER_get_packet(&s
->rlayer
);
212 if (!PACKET_buf_init(&pkt
, RECORD_LAYER_get_packet(&s
->rlayer
),
213 RECORD_LAYER_get_packet_length(&s
->rlayer
))) {
214 al
= SSL_AD_INTERNAL_ERROR
;
215 SSLerr(SSL_F_SSL3_GET_RECORD
, ERR_R_INTERNAL_ERROR
);
219 if (!PACKET_get_net_2_len(&sslv2pkt
, &sslv2len
)
220 || !PACKET_get_1(&sslv2pkt
, &type
)) {
221 al
= SSL_AD_DECODE_ERROR
;
222 SSLerr(SSL_F_SSL3_GET_RECORD
, ERR_R_INTERNAL_ERROR
);
226 * The first record received by the server may be a V2ClientHello.
228 if (s
->server
&& RECORD_LAYER_is_first_record(&s
->rlayer
)
229 && (sslv2len
& 0x8000) != 0
230 && (type
== SSL2_MT_CLIENT_HELLO
)) {
234 * |num_recs| here will actually always be 0 because
235 * |num_recs > 0| only ever occurs when we are processing
236 * multiple app data records - which we know isn't the case here
237 * because it is an SSLv2ClientHello. We keep it using
238 * |num_recs| for the sake of consistency
240 thisrr
->type
= SSL3_RT_HANDSHAKE
;
241 thisrr
->rec_version
= SSL2_VERSION
;
243 thisrr
->length
= sslv2len
& 0x7fff;
245 if (thisrr
->length
> SSL3_BUFFER_get_len(rbuf
)
246 - SSL2_RT_HEADER_LENGTH
) {
247 al
= SSL_AD_RECORD_OVERFLOW
;
248 SSLerr(SSL_F_SSL3_GET_RECORD
, SSL_R_PACKET_LENGTH_TOO_LONG
);
252 if (thisrr
->length
< MIN_SSL2_RECORD_LEN
) {
253 al
= SSL_AD_DECODE_ERROR
;
254 SSLerr(SSL_F_SSL3_GET_RECORD
, SSL_R_LENGTH_TOO_SHORT
);
258 /* SSLv3+ style record */
260 s
->msg_callback(0, 0, SSL3_RT_HEADER
, p
, 5, s
,
261 s
->msg_callback_arg
);
263 /* Pull apart the header into the SSL3_RECORD */
264 if (!PACKET_get_1(&pkt
, &type
)
265 || !PACKET_get_net_2(&pkt
, &version
)
266 || !PACKET_get_net_2_len(&pkt
, &thisrr
->length
)) {
267 al
= SSL_AD_DECODE_ERROR
;
268 SSLerr(SSL_F_SSL3_GET_RECORD
, ERR_R_INTERNAL_ERROR
);
272 thisrr
->rec_version
= version
;
275 * Lets check version. In TLSv1.3 we ignore this field. For the
276 * ServerHello after an HRR we haven't actually selected TLSv1.3
277 * yet, but we still treat it as TLSv1.3, so we must check for
280 if (!s
->first_packet
&& !SSL_IS_TLS13(s
)
281 && !s
->hello_retry_request
282 && version
!= (unsigned int)s
->version
) {
283 SSLerr(SSL_F_SSL3_GET_RECORD
, SSL_R_WRONG_VERSION_NUMBER
);
284 if ((s
->version
& 0xFF00) == (version
& 0xFF00)
285 && !s
->enc_write_ctx
&& !s
->write_hash
) {
286 if (thisrr
->type
== SSL3_RT_ALERT
) {
288 * The record is using an incorrect version number,
289 * but what we've got appears to be an alert. We
290 * haven't read the body yet to check whether its a
291 * fatal or not - but chances are it is. We probably
292 * shouldn't send a fatal alert back. We'll just
298 * Send back error using their minor version number :-)
300 s
->version
= (unsigned short)version
;
302 al
= SSL_AD_PROTOCOL_VERSION
;
306 if ((version
>> 8) != SSL3_VERSION_MAJOR
) {
307 if (RECORD_LAYER_is_first_record(&s
->rlayer
)) {
308 /* Go back to start of packet, look at the five bytes
310 p
= RECORD_LAYER_get_packet(&s
->rlayer
);
311 if (strncmp((char *)p
, "GET ", 4) == 0 ||
312 strncmp((char *)p
, "POST ", 5) == 0 ||
313 strncmp((char *)p
, "HEAD ", 5) == 0 ||
314 strncmp((char *)p
, "PUT ", 4) == 0) {
315 SSLerr(SSL_F_SSL3_GET_RECORD
, SSL_R_HTTP_REQUEST
);
317 } else if (strncmp((char *)p
, "CONNE", 5) == 0) {
318 SSLerr(SSL_F_SSL3_GET_RECORD
,
319 SSL_R_HTTPS_PROXY_REQUEST
);
323 /* Doesn't look like TLS - don't send an alert */
324 SSLerr(SSL_F_SSL3_GET_RECORD
,
325 SSL_R_WRONG_VERSION_NUMBER
);
328 SSLerr(SSL_F_SSL3_GET_RECORD
,
329 SSL_R_WRONG_VERSION_NUMBER
);
330 al
= SSL_AD_PROTOCOL_VERSION
;
335 if (SSL_IS_TLS13(s
) && s
->enc_read_ctx
!= NULL
336 && thisrr
->type
!= SSL3_RT_APPLICATION_DATA
) {
337 SSLerr(SSL_F_SSL3_GET_RECORD
, SSL_R_BAD_RECORD_TYPE
);
338 al
= SSL_AD_UNEXPECTED_MESSAGE
;
343 SSL3_BUFFER_get_len(rbuf
) - SSL3_RT_HEADER_LENGTH
) {
344 al
= SSL_AD_RECORD_OVERFLOW
;
345 SSLerr(SSL_F_SSL3_GET_RECORD
, SSL_R_PACKET_LENGTH_TOO_LONG
);
350 /* now s->rlayer.rstate == SSL_ST_READ_BODY */
353 if (SSL_IS_TLS13(s
)) {
354 if (thisrr
->length
> SSL3_RT_MAX_TLS13_ENCRYPTED_LENGTH
) {
355 al
= SSL_AD_RECORD_OVERFLOW
;
356 SSLerr(SSL_F_SSL3_GET_RECORD
, SSL_R_ENCRYPTED_LENGTH_TOO_LONG
);
360 size_t len
= SSL3_RT_MAX_ENCRYPTED_LENGTH
;
362 #ifndef OPENSSL_NO_COMP
364 * If OPENSSL_NO_COMP is defined then SSL3_RT_MAX_ENCRYPTED_LENGTH
365 * does not include the compression overhead anyway.
367 if (s
->expand
== NULL
)
368 len
-= SSL3_RT_MAX_COMPRESSED_OVERHEAD
;
371 if (thisrr
->length
> len
) {
372 al
= SSL_AD_RECORD_OVERFLOW
;
373 SSLerr(SSL_F_SSL3_GET_RECORD
, SSL_R_ENCRYPTED_LENGTH_TOO_LONG
);
379 * s->rlayer.rstate == SSL_ST_READ_BODY, get and decode the data.
380 * Calculate how much more data we need to read for the rest of the
383 if (thisrr
->rec_version
== SSL2_VERSION
) {
384 more
= thisrr
->length
+ SSL2_RT_HEADER_LENGTH
385 - SSL3_RT_HEADER_LENGTH
;
387 more
= thisrr
->length
;
390 /* now s->packet_length == SSL3_RT_HEADER_LENGTH */
392 rret
= ssl3_read_n(s
, more
, more
, 1, 0, &n
);
394 return rret
; /* error or non-blocking io */
397 /* set state for later operations */
398 RECORD_LAYER_set_rstate(&s
->rlayer
, SSL_ST_READ_HEADER
);
401 * At this point, s->packet_length == SSL3_RT_HEADER_LENGTH
402 * + thisrr->length, or s->packet_length == SSL2_RT_HEADER_LENGTH
403 * + thisrr->length and we have that many bytes in s->packet
405 if (thisrr
->rec_version
== SSL2_VERSION
) {
407 &(RECORD_LAYER_get_packet(&s
->rlayer
)[SSL2_RT_HEADER_LENGTH
]);
410 &(RECORD_LAYER_get_packet(&s
->rlayer
)[SSL3_RT_HEADER_LENGTH
]);
414 * ok, we can now read from 's->packet' data into 'thisrr' thisrr->input
415 * points at thisrr->length bytes, which need to be copied into
416 * thisrr->data by either the decryption or by the decompression When
417 * the data is 'copied' into the thisrr->data buffer, thisrr->input will
418 * be pointed at the new buffer
422 * We now have - encrypted [ MAC [ compressed [ plain ] ] ]
423 * thisrr->length bytes of encrypted compressed stuff.
426 /* decrypt in place in 'thisrr->input' */
427 thisrr
->data
= thisrr
->input
;
428 thisrr
->orig_len
= thisrr
->length
;
430 /* Mark this record as not read by upper layers yet */
435 /* we have pulled in a full packet so zero things */
436 RECORD_LAYER_reset_packet_length(&s
->rlayer
);
437 RECORD_LAYER_clear_first_record(&s
->rlayer
);
438 } while (num_recs
< max_recs
439 && thisrr
->type
== SSL3_RT_APPLICATION_DATA
440 && SSL_USE_EXPLICIT_IV(s
)
441 && s
->enc_read_ctx
!= NULL
442 && (EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(s
->enc_read_ctx
))
443 & EVP_CIPH_FLAG_PIPELINE
)
444 && ssl3_record_app_data_waiting(s
));
447 * If in encrypt-then-mac mode calculate mac from encrypted record. All
448 * the details below are public so no timing details can leak.
450 if (SSL_READ_ETM(s
) && s
->read_hash
) {
452 /* TODO(size_t): convert this to do size_t properly */
453 imac_size
= EVP_MD_CTX_size(s
->read_hash
);
454 if (!ossl_assert(imac_size
>= 0 && imac_size
<= EVP_MAX_MD_SIZE
)) {
455 al
= SSL_AD_INTERNAL_ERROR
;
456 SSLerr(SSL_F_SSL3_GET_RECORD
, ERR_LIB_EVP
);
459 mac_size
= (size_t)imac_size
;
460 for (j
= 0; j
< num_recs
; j
++) {
463 if (thisrr
->length
< mac_size
) {
464 al
= SSL_AD_DECODE_ERROR
;
465 SSLerr(SSL_F_SSL3_GET_RECORD
, SSL_R_LENGTH_TOO_SHORT
);
468 thisrr
->length
-= mac_size
;
469 mac
= thisrr
->data
+ thisrr
->length
;
470 i
= s
->method
->ssl3_enc
->mac(s
, thisrr
, md
, 0 /* not send */ );
471 if (i
== 0 || CRYPTO_memcmp(md
, mac
, mac_size
) != 0) {
472 al
= SSL_AD_BAD_RECORD_MAC
;
473 SSLerr(SSL_F_SSL3_GET_RECORD
,
474 SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC
);
480 first_rec_len
= rr
[0].length
;
482 enc_err
= s
->method
->ssl3_enc
->enc(s
, rr
, num_recs
, 0);
486 * 0: (in non-constant time) if the record is publicly invalid.
487 * 1: if the padding is valid
488 * -1: if the padding is invalid
491 if (num_recs
== 1 && ossl_statem_skip_early_data(s
)) {
493 * Valid early_data that we cannot decrypt might fail here as
494 * publicly invalid. We treat it like an empty record.
499 if (!early_data_count_ok(s
, thisrr
->length
,
500 EARLY_DATA_CIPHERTEXT_OVERHEAD
, &al
))
505 RECORD_LAYER_set_numrpipes(&s
->rlayer
, 1);
506 RECORD_LAYER_reset_read_sequence(&s
->rlayer
);
509 al
= SSL_AD_DECRYPTION_FAILED
;
510 SSLerr(SSL_F_SSL3_GET_RECORD
, SSL_R_BLOCK_CIPHER_PAD_IS_WRONG
);
514 printf("dec %"OSSLzu
"\n", rr
[0].length
);
517 for (z
= 0; z
< rr
[0].length
; z
++)
518 printf("%02X%c", rr
[0].data
[z
], ((z
+ 1) % 16) ? ' ' : '\n');
523 /* r->length is now the compressed data plus mac */
524 if ((sess
!= NULL
) &&
525 (s
->enc_read_ctx
!= NULL
) &&
526 (!SSL_READ_ETM(s
) && EVP_MD_CTX_md(s
->read_hash
) != NULL
)) {
527 /* s->read_hash != NULL => mac_size != -1 */
528 unsigned char *mac
= NULL
;
529 unsigned char mac_tmp
[EVP_MAX_MD_SIZE
];
531 mac_size
= EVP_MD_CTX_size(s
->read_hash
);
532 if (!ossl_assert(mac_size
<= EVP_MAX_MD_SIZE
)) {
533 al
= SSL_AD_INTERNAL_ERROR
;
534 SSLerr(SSL_F_SSL3_GET_RECORD
, ERR_R_INTERNAL_ERROR
);
538 for (j
= 0; j
< num_recs
; j
++) {
541 * orig_len is the length of the record before any padding was
542 * removed. This is public information, as is the MAC in use,
543 * therefore we can safely process the record in a different amount
544 * of time if it's too short to possibly contain a MAC.
546 if (thisrr
->orig_len
< mac_size
||
547 /* CBC records must have a padding length byte too. */
548 (EVP_CIPHER_CTX_mode(s
->enc_read_ctx
) == EVP_CIPH_CBC_MODE
&&
549 thisrr
->orig_len
< mac_size
+ 1)) {
550 al
= SSL_AD_DECODE_ERROR
;
551 SSLerr(SSL_F_SSL3_GET_RECORD
, SSL_R_LENGTH_TOO_SHORT
);
555 if (EVP_CIPHER_CTX_mode(s
->enc_read_ctx
) == EVP_CIPH_CBC_MODE
) {
557 * We update the length so that the TLS header bytes can be
558 * constructed correctly but we need to extract the MAC in
559 * constant time from within the record, without leaking the
560 * contents of the padding bytes.
563 if (!ssl3_cbc_copy_mac(mac_tmp
, thisrr
, mac_size
)) {
564 al
= SSL_AD_INTERNAL_ERROR
;
565 SSLerr(SSL_F_SSL3_GET_RECORD
, ERR_R_INTERNAL_ERROR
);
568 thisrr
->length
-= mac_size
;
571 * In this case there's no padding, so |rec->orig_len| equals
572 * |rec->length| and we checked that there's enough bytes for
575 thisrr
->length
-= mac_size
;
576 mac
= &thisrr
->data
[thisrr
->length
];
579 i
= s
->method
->ssl3_enc
->mac(s
, thisrr
, md
, 0 /* not send */ );
580 if (i
== 0 || mac
== NULL
581 || CRYPTO_memcmp(md
, mac
, (size_t)mac_size
) != 0)
583 if (thisrr
->length
> SSL3_RT_MAX_COMPRESSED_LENGTH
+ mac_size
)
589 if (num_recs
== 1 && ossl_statem_skip_early_data(s
)) {
591 * We assume this is unreadable early_data - we treat it like an
596 * The record length may have been modified by the mac check above
597 * so we use the previously saved value
599 if (!early_data_count_ok(s
, first_rec_len
,
600 EARLY_DATA_CIPHERTEXT_OVERHEAD
, &al
))
606 RECORD_LAYER_set_numrpipes(&s
->rlayer
, 1);
607 RECORD_LAYER_reset_read_sequence(&s
->rlayer
);
611 * A separate 'decryption_failed' alert was introduced with TLS 1.0,
612 * SSL 3.0 only has 'bad_record_mac'. But unless a decryption
613 * failure is directly visible from the ciphertext anyway, we should
614 * not reveal which kind of error occurred -- this might become
615 * visible to an attacker (e.g. via a logfile)
617 al
= SSL_AD_BAD_RECORD_MAC
;
618 SSLerr(SSL_F_SSL3_GET_RECORD
,
619 SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC
);
623 for (j
= 0; j
< num_recs
; j
++) {
626 /* thisrr->length is now just compressed */
627 if (s
->expand
!= NULL
) {
628 if (thisrr
->length
> SSL3_RT_MAX_COMPRESSED_LENGTH
) {
629 al
= SSL_AD_RECORD_OVERFLOW
;
630 SSLerr(SSL_F_SSL3_GET_RECORD
, SSL_R_COMPRESSED_LENGTH_TOO_LONG
);
633 if (!ssl3_do_uncompress(s
, thisrr
)) {
634 al
= SSL_AD_DECOMPRESSION_FAILURE
;
635 SSLerr(SSL_F_SSL3_GET_RECORD
, SSL_R_BAD_DECOMPRESSION
);
640 if (SSL_IS_TLS13(s
) && s
->enc_read_ctx
!= NULL
) {
643 if (thisrr
->length
== 0
644 || thisrr
->type
!= SSL3_RT_APPLICATION_DATA
) {
645 al
= SSL_AD_UNEXPECTED_MESSAGE
;
646 SSLerr(SSL_F_SSL3_GET_RECORD
, SSL_R_BAD_RECORD_TYPE
);
650 /* Strip trailing padding */
651 for (end
= thisrr
->length
- 1; end
> 0 && thisrr
->data
[end
] == 0;
655 thisrr
->length
= end
;
656 thisrr
->type
= thisrr
->data
[end
];
657 if (thisrr
->type
!= SSL3_RT_APPLICATION_DATA
658 && thisrr
->type
!= SSL3_RT_ALERT
659 && thisrr
->type
!= SSL3_RT_HANDSHAKE
) {
660 al
= SSL_AD_UNEXPECTED_MESSAGE
;
661 SSLerr(SSL_F_SSL3_GET_RECORD
, SSL_R_BAD_RECORD_TYPE
);
665 s
->msg_callback(0, s
->version
, SSL3_RT_INNER_CONTENT_TYPE
,
666 &thisrr
->data
[end
], 1, s
, s
->msg_callback_arg
);
670 * TLSv1.3 alert and handshake records are required to be non-zero in
674 && (thisrr
->type
== SSL3_RT_HANDSHAKE
675 || thisrr
->type
== SSL3_RT_ALERT
)
676 && thisrr
->length
== 0) {
677 al
= SSL_AD_UNEXPECTED_MESSAGE
;
678 SSLerr(SSL_F_SSL3_GET_RECORD
, SSL_R_BAD_LENGTH
);
682 if (thisrr
->length
> SSL3_RT_MAX_PLAIN_LENGTH
) {
683 al
= SSL_AD_RECORD_OVERFLOW
;
684 SSLerr(SSL_F_SSL3_GET_RECORD
, SSL_R_DATA_LENGTH_TOO_LONG
);
688 /* If received packet overflows current Max Fragment Length setting */
689 if (s
->session
!= NULL
&& USE_MAX_FRAGMENT_LENGTH_EXT(s
->session
)
690 && thisrr
->length
> GET_MAX_FRAGMENT_LENGTH(s
->session
)) {
691 al
= SSL_AD_RECORD_OVERFLOW
;
692 SSLerr(SSL_F_SSL3_GET_RECORD
, SSL_R_DATA_LENGTH_TOO_LONG
);
698 * So at this point the following is true
699 * thisrr->type is the type of record
700 * thisrr->length == number of bytes in record
701 * thisrr->off == offset to first valid byte
702 * thisrr->data == where to take bytes from, increment after use :-).
705 /* just read a 0 length packet */
706 if (thisrr
->length
== 0) {
707 RECORD_LAYER_inc_empty_record_count(&s
->rlayer
);
708 if (RECORD_LAYER_get_empty_record_count(&s
->rlayer
)
709 > MAX_EMPTY_RECORDS
) {
710 al
= SSL_AD_UNEXPECTED_MESSAGE
;
711 SSLerr(SSL_F_SSL3_GET_RECORD
, SSL_R_RECORD_TOO_SMALL
);
715 RECORD_LAYER_reset_empty_record_count(&s
->rlayer
);
719 if (s
->early_data_state
== SSL_EARLY_DATA_READING
) {
721 if (thisrr
->type
== SSL3_RT_APPLICATION_DATA
722 && !early_data_count_ok(s
, thisrr
->length
, 0, &al
))
726 RECORD_LAYER_set_numrpipes(&s
->rlayer
, num_recs
);
730 ssl3_send_alert(s
, SSL3_AL_FATAL
, al
);
735 int ssl3_do_uncompress(SSL
*ssl
, SSL3_RECORD
*rr
)
737 #ifndef OPENSSL_NO_COMP
740 if (rr
->comp
== NULL
) {
741 rr
->comp
= (unsigned char *)
742 OPENSSL_malloc(SSL3_RT_MAX_ENCRYPTED_LENGTH
);
744 if (rr
->comp
== NULL
)
747 /* TODO(size_t): Convert this call */
748 i
= COMP_expand_block(ssl
->expand
, rr
->comp
,
749 SSL3_RT_MAX_PLAIN_LENGTH
, rr
->data
, (int)rr
->length
);
759 int ssl3_do_compress(SSL
*ssl
, SSL3_RECORD
*wr
)
761 #ifndef OPENSSL_NO_COMP
764 /* TODO(size_t): Convert this call */
765 i
= COMP_compress_block(ssl
->compress
, wr
->data
,
766 (int)(wr
->length
+ SSL3_RT_MAX_COMPRESSED_OVERHEAD
),
767 wr
->input
, (int)wr
->length
);
773 wr
->input
= wr
->data
;
779 * ssl3_enc encrypts/decrypts |n_recs| records in |inrecs|
782 * 0: (in non-constant time) if the record is publically invalid (i.e. too
784 * 1: if the record's padding is valid / the encryption was successful.
785 * -1: if the record's padding is invalid or, if sending, an internal error
788 int ssl3_enc(SSL
*s
, SSL3_RECORD
*inrecs
, size_t n_recs
, int sending
)
793 size_t bs
, mac_size
= 0;
795 const EVP_CIPHER
*enc
;
799 * We shouldn't ever be called with more than one record in the SSLv3 case
804 ds
= s
->enc_write_ctx
;
805 if (s
->enc_write_ctx
== NULL
)
808 enc
= EVP_CIPHER_CTX_cipher(s
->enc_write_ctx
);
810 ds
= s
->enc_read_ctx
;
811 if (s
->enc_read_ctx
== NULL
)
814 enc
= EVP_CIPHER_CTX_cipher(s
->enc_read_ctx
);
817 if ((s
->session
== NULL
) || (ds
== NULL
) || (enc
== NULL
)) {
818 memmove(rec
->data
, rec
->input
, rec
->length
);
819 rec
->input
= rec
->data
;
822 /* TODO(size_t): Convert this call */
823 bs
= EVP_CIPHER_CTX_block_size(ds
);
827 if ((bs
!= 1) && sending
) {
830 /* we need to add 'i-1' padding bytes */
833 * the last of these zero bytes will be overwritten with the
836 memset(&rec
->input
[rec
->length
], 0, i
);
838 rec
->input
[l
- 1] = (unsigned char)(i
- 1);
842 if (l
== 0 || l
% bs
!= 0)
844 /* otherwise, rec->length >= bs */
847 /* TODO(size_t): Convert this call */
848 if (EVP_Cipher(ds
, rec
->data
, rec
->input
, (unsigned int)l
) < 1)
851 if (EVP_MD_CTX_md(s
->read_hash
) != NULL
) {
852 /* TODO(size_t): convert me */
853 imac_size
= EVP_MD_CTX_size(s
->read_hash
);
856 mac_size
= (size_t)imac_size
;
858 if ((bs
!= 1) && !sending
)
859 return ssl3_cbc_remove_padding(rec
, bs
, mac_size
);
864 #define MAX_PADDING 256
866 * tls1_enc encrypts/decrypts |n_recs| in |recs|.
869 * 0: (in non-constant time) if the record is publically invalid (i.e. too
871 * 1: if the record's padding is valid / the encryption was successful.
872 * -1: if the record's padding/AEAD-authenticator is invalid or, if sending,
873 * an internal error occurred.
875 int tls1_enc(SSL
*s
, SSL3_RECORD
*recs
, size_t n_recs
, int sending
)
878 size_t reclen
[SSL_MAX_PIPELINES
];
879 unsigned char buf
[SSL_MAX_PIPELINES
][EVP_AEAD_TLS1_AAD_LEN
];
880 int i
, pad
= 0, ret
, tmpr
;
881 size_t bs
, mac_size
= 0, ctr
, padnum
, loop
;
882 unsigned char padval
;
884 const EVP_CIPHER
*enc
;
890 if (EVP_MD_CTX_md(s
->write_hash
)) {
891 int n
= EVP_MD_CTX_size(s
->write_hash
);
892 if (!ossl_assert(n
>= 0)) {
893 SSLerr(SSL_F_TLS1_ENC
, ERR_R_INTERNAL_ERROR
);
897 ds
= s
->enc_write_ctx
;
898 if (s
->enc_write_ctx
== NULL
)
902 enc
= EVP_CIPHER_CTX_cipher(s
->enc_write_ctx
);
903 /* For TLSv1.1 and later explicit IV */
904 if (SSL_USE_EXPLICIT_IV(s
)
905 && EVP_CIPHER_mode(enc
) == EVP_CIPH_CBC_MODE
)
906 ivlen
= EVP_CIPHER_iv_length(enc
);
910 for (ctr
= 0; ctr
< n_recs
; ctr
++) {
911 if (recs
[ctr
].data
!= recs
[ctr
].input
) {
913 * we can't write into the input stream: Can this ever
916 SSLerr(SSL_F_TLS1_ENC
, ERR_R_INTERNAL_ERROR
);
918 } else if (ssl_randbytes(s
, recs
[ctr
].input
, ivlen
) <= 0) {
919 SSLerr(SSL_F_TLS1_ENC
, ERR_R_INTERNAL_ERROR
);
926 if (EVP_MD_CTX_md(s
->read_hash
)) {
927 int n
= EVP_MD_CTX_size(s
->read_hash
);
928 if (!ossl_assert(n
>= 0)) {
929 SSLerr(SSL_F_TLS1_ENC
, ERR_R_INTERNAL_ERROR
);
933 ds
= s
->enc_read_ctx
;
934 if (s
->enc_read_ctx
== NULL
)
937 enc
= EVP_CIPHER_CTX_cipher(s
->enc_read_ctx
);
940 if ((s
->session
== NULL
) || (ds
== NULL
) || (enc
== NULL
)) {
941 for (ctr
= 0; ctr
< n_recs
; ctr
++) {
942 memmove(recs
[ctr
].data
, recs
[ctr
].input
, recs
[ctr
].length
);
943 recs
[ctr
].input
= recs
[ctr
].data
;
947 bs
= EVP_CIPHER_block_size(EVP_CIPHER_CTX_cipher(ds
));
950 if (!(EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(ds
))
951 & EVP_CIPH_FLAG_PIPELINE
)) {
953 * We shouldn't have been called with pipeline data if the
954 * cipher doesn't support pipelining
956 SSLerr(SSL_F_TLS1_ENC
, SSL_R_PIPELINE_FAILURE
);
960 for (ctr
= 0; ctr
< n_recs
; ctr
++) {
961 reclen
[ctr
] = recs
[ctr
].length
;
963 if (EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(ds
))
964 & EVP_CIPH_FLAG_AEAD_CIPHER
) {
967 seq
= sending
? RECORD_LAYER_get_write_sequence(&s
->rlayer
)
968 : RECORD_LAYER_get_read_sequence(&s
->rlayer
);
970 if (SSL_IS_DTLS(s
)) {
971 /* DTLS does not support pipelining */
972 unsigned char dtlsseq
[9], *p
= dtlsseq
;
974 s2n(sending
? DTLS_RECORD_LAYER_get_w_epoch(&s
->rlayer
) :
975 DTLS_RECORD_LAYER_get_r_epoch(&s
->rlayer
), p
);
976 memcpy(p
, &seq
[2], 6);
977 memcpy(buf
[ctr
], dtlsseq
, 8);
979 memcpy(buf
[ctr
], seq
, 8);
980 for (i
= 7; i
>= 0; i
--) { /* increment */
987 buf
[ctr
][8] = recs
[ctr
].type
;
988 buf
[ctr
][9] = (unsigned char)(s
->version
>> 8);
989 buf
[ctr
][10] = (unsigned char)(s
->version
);
990 buf
[ctr
][11] = (unsigned char)(recs
[ctr
].length
>> 8);
991 buf
[ctr
][12] = (unsigned char)(recs
[ctr
].length
& 0xff);
992 pad
= EVP_CIPHER_CTX_ctrl(ds
, EVP_CTRL_AEAD_TLS1_AAD
,
993 EVP_AEAD_TLS1_AAD_LEN
, buf
[ctr
]);
999 recs
[ctr
].length
+= pad
;
1002 } else if ((bs
!= 1) && sending
) {
1003 padnum
= bs
- (reclen
[ctr
] % bs
);
1005 /* Add weird padding of upto 256 bytes */
1007 if (padnum
> MAX_PADDING
)
1009 /* we need to add 'padnum' padding bytes of value padval */
1010 padval
= (unsigned char)(padnum
- 1);
1011 for (loop
= reclen
[ctr
]; loop
< reclen
[ctr
] + padnum
; loop
++)
1012 recs
[ctr
].input
[loop
] = padval
;
1013 reclen
[ctr
] += padnum
;
1014 recs
[ctr
].length
+= padnum
;
1018 if (reclen
[ctr
] == 0 || reclen
[ctr
] % bs
!= 0)
1023 unsigned char *data
[SSL_MAX_PIPELINES
];
1025 /* Set the output buffers */
1026 for (ctr
= 0; ctr
< n_recs
; ctr
++) {
1027 data
[ctr
] = recs
[ctr
].data
;
1029 if (EVP_CIPHER_CTX_ctrl(ds
, EVP_CTRL_SET_PIPELINE_OUTPUT_BUFS
,
1030 (int)n_recs
, data
) <= 0) {
1031 SSLerr(SSL_F_TLS1_ENC
, SSL_R_PIPELINE_FAILURE
);
1033 /* Set the input buffers */
1034 for (ctr
= 0; ctr
< n_recs
; ctr
++) {
1035 data
[ctr
] = recs
[ctr
].input
;
1037 if (EVP_CIPHER_CTX_ctrl(ds
, EVP_CTRL_SET_PIPELINE_INPUT_BUFS
,
1038 (int)n_recs
, data
) <= 0
1039 || EVP_CIPHER_CTX_ctrl(ds
, EVP_CTRL_SET_PIPELINE_INPUT_LENS
,
1040 (int)n_recs
, reclen
) <= 0) {
1041 SSLerr(SSL_F_TLS1_ENC
, SSL_R_PIPELINE_FAILURE
);
1046 /* TODO(size_t): Convert this call */
1047 tmpr
= EVP_Cipher(ds
, recs
[0].data
, recs
[0].input
,
1048 (unsigned int)reclen
[0]);
1049 if ((EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(ds
))
1050 & EVP_CIPH_FLAG_CUSTOM_CIPHER
)
1053 return -1; /* AEAD can fail to verify MAC */
1055 if (EVP_CIPHER_mode(enc
) == EVP_CIPH_GCM_MODE
) {
1056 for (ctr
= 0; ctr
< n_recs
; ctr
++) {
1057 recs
[ctr
].data
+= EVP_GCM_TLS_EXPLICIT_IV_LEN
;
1058 recs
[ctr
].input
+= EVP_GCM_TLS_EXPLICIT_IV_LEN
;
1059 recs
[ctr
].length
-= EVP_GCM_TLS_EXPLICIT_IV_LEN
;
1061 } else if (EVP_CIPHER_mode(enc
) == EVP_CIPH_CCM_MODE
) {
1062 for (ctr
= 0; ctr
< n_recs
; ctr
++) {
1063 recs
[ctr
].data
+= EVP_CCM_TLS_EXPLICIT_IV_LEN
;
1064 recs
[ctr
].input
+= EVP_CCM_TLS_EXPLICIT_IV_LEN
;
1065 recs
[ctr
].length
-= EVP_CCM_TLS_EXPLICIT_IV_LEN
;
1071 if (!SSL_READ_ETM(s
) && EVP_MD_CTX_md(s
->read_hash
) != NULL
) {
1072 imac_size
= EVP_MD_CTX_size(s
->read_hash
);
1075 mac_size
= (size_t)imac_size
;
1077 if ((bs
!= 1) && !sending
) {
1079 for (ctr
= 0; ctr
< n_recs
; ctr
++) {
1080 tmpret
= tls1_cbc_remove_padding(s
, &recs
[ctr
], bs
, mac_size
);
1082 * If tmpret == 0 then this means publicly invalid so we can
1083 * short circuit things here. Otherwise we must respect constant
1088 ret
= constant_time_select_int(constant_time_eq_int(tmpret
, 1),
1092 if (pad
&& !sending
) {
1093 for (ctr
= 0; ctr
< n_recs
; ctr
++) {
1094 recs
[ctr
].length
-= pad
;
1101 int n_ssl3_mac(SSL
*ssl
, SSL3_RECORD
*rec
, unsigned char *md
, int sending
)
1103 unsigned char *mac_sec
, *seq
;
1104 const EVP_MD_CTX
*hash
;
1105 unsigned char *p
, rec_char
;
1111 mac_sec
= &(ssl
->s3
->write_mac_secret
[0]);
1112 seq
= RECORD_LAYER_get_write_sequence(&ssl
->rlayer
);
1113 hash
= ssl
->write_hash
;
1115 mac_sec
= &(ssl
->s3
->read_mac_secret
[0]);
1116 seq
= RECORD_LAYER_get_read_sequence(&ssl
->rlayer
);
1117 hash
= ssl
->read_hash
;
1120 t
= EVP_MD_CTX_size(hash
);
1124 npad
= (48 / md_size
) * md_size
;
1127 EVP_CIPHER_CTX_mode(ssl
->enc_read_ctx
) == EVP_CIPH_CBC_MODE
&&
1128 ssl3_cbc_record_digest_supported(hash
)) {
1130 * This is a CBC-encrypted record. We must avoid leaking any
1131 * timing-side channel information about how many blocks of data we
1132 * are hashing because that gives an attacker a timing-oracle.
1136 * npad is, at most, 48 bytes and that's with MD5:
1137 * 16 + 48 + 8 (sequence bytes) + 1 + 2 = 75.
1139 * With SHA-1 (the largest hash speced for SSLv3) the hash size
1140 * goes up 4, but npad goes down by 8, resulting in a smaller
1143 unsigned char header
[75];
1145 memcpy(header
+ j
, mac_sec
, md_size
);
1147 memcpy(header
+ j
, ssl3_pad_1
, npad
);
1149 memcpy(header
+ j
, seq
, 8);
1151 header
[j
++] = rec
->type
;
1152 header
[j
++] = (unsigned char)(rec
->length
>> 8);
1153 header
[j
++] = (unsigned char)(rec
->length
& 0xff);
1155 /* Final param == is SSLv3 */
1156 if (ssl3_cbc_digest_record(hash
,
1159 rec
->length
+ md_size
, rec
->orig_len
,
1160 mac_sec
, md_size
, 1) <= 0)
1163 unsigned int md_size_u
;
1164 /* Chop the digest off the end :-) */
1165 EVP_MD_CTX
*md_ctx
= EVP_MD_CTX_new();
1170 rec_char
= rec
->type
;
1172 s2n(rec
->length
, p
);
1173 if (EVP_MD_CTX_copy_ex(md_ctx
, hash
) <= 0
1174 || EVP_DigestUpdate(md_ctx
, mac_sec
, md_size
) <= 0
1175 || EVP_DigestUpdate(md_ctx
, ssl3_pad_1
, npad
) <= 0
1176 || EVP_DigestUpdate(md_ctx
, seq
, 8) <= 0
1177 || EVP_DigestUpdate(md_ctx
, &rec_char
, 1) <= 0
1178 || EVP_DigestUpdate(md_ctx
, md
, 2) <= 0
1179 || EVP_DigestUpdate(md_ctx
, rec
->input
, rec
->length
) <= 0
1180 || EVP_DigestFinal_ex(md_ctx
, md
, NULL
) <= 0
1181 || EVP_MD_CTX_copy_ex(md_ctx
, hash
) <= 0
1182 || EVP_DigestUpdate(md_ctx
, mac_sec
, md_size
) <= 0
1183 || EVP_DigestUpdate(md_ctx
, ssl3_pad_2
, npad
) <= 0
1184 || EVP_DigestUpdate(md_ctx
, md
, md_size
) <= 0
1185 || EVP_DigestFinal_ex(md_ctx
, md
, &md_size_u
) <= 0) {
1186 EVP_MD_CTX_reset(md_ctx
);
1190 EVP_MD_CTX_free(md_ctx
);
1193 ssl3_record_sequence_update(seq
);
1197 int tls1_mac(SSL
*ssl
, SSL3_RECORD
*rec
, unsigned char *md
, int sending
)
1203 EVP_MD_CTX
*hmac
= NULL
, *mac_ctx
;
1204 unsigned char header
[13];
1205 int stream_mac
= (sending
? (ssl
->mac_flags
& SSL_MAC_FLAG_WRITE_MAC_STREAM
)
1206 : (ssl
->mac_flags
& SSL_MAC_FLAG_READ_MAC_STREAM
));
1210 seq
= RECORD_LAYER_get_write_sequence(&ssl
->rlayer
);
1211 hash
= ssl
->write_hash
;
1213 seq
= RECORD_LAYER_get_read_sequence(&ssl
->rlayer
);
1214 hash
= ssl
->read_hash
;
1217 t
= EVP_MD_CTX_size(hash
);
1218 if (!ossl_assert(t
>= 0))
1222 /* I should fix this up TLS TLS TLS TLS TLS XXXXXXXX */
1226 hmac
= EVP_MD_CTX_new();
1227 if (hmac
== NULL
|| !EVP_MD_CTX_copy(hmac
, hash
))
1232 if (SSL_IS_DTLS(ssl
)) {
1233 unsigned char dtlsseq
[8], *p
= dtlsseq
;
1235 s2n(sending
? DTLS_RECORD_LAYER_get_w_epoch(&ssl
->rlayer
) :
1236 DTLS_RECORD_LAYER_get_r_epoch(&ssl
->rlayer
), p
);
1237 memcpy(p
, &seq
[2], 6);
1239 memcpy(header
, dtlsseq
, 8);
1241 memcpy(header
, seq
, 8);
1243 header
[8] = rec
->type
;
1244 header
[9] = (unsigned char)(ssl
->version
>> 8);
1245 header
[10] = (unsigned char)(ssl
->version
);
1246 header
[11] = (unsigned char)(rec
->length
>> 8);
1247 header
[12] = (unsigned char)(rec
->length
& 0xff);
1249 if (!sending
&& !SSL_READ_ETM(ssl
) &&
1250 EVP_CIPHER_CTX_mode(ssl
->enc_read_ctx
) == EVP_CIPH_CBC_MODE
&&
1251 ssl3_cbc_record_digest_supported(mac_ctx
)) {
1253 * This is a CBC-encrypted record. We must avoid leaking any
1254 * timing-side channel information about how many blocks of data we
1255 * are hashing because that gives an attacker a timing-oracle.
1257 /* Final param == not SSLv3 */
1258 if (ssl3_cbc_digest_record(mac_ctx
,
1261 rec
->length
+ md_size
, rec
->orig_len
,
1262 ssl
->s3
->read_mac_secret
,
1263 ssl
->s3
->read_mac_secret_size
, 0) <= 0) {
1264 EVP_MD_CTX_free(hmac
);
1268 /* TODO(size_t): Convert these calls */
1269 if (EVP_DigestSignUpdate(mac_ctx
, header
, sizeof(header
)) <= 0
1270 || EVP_DigestSignUpdate(mac_ctx
, rec
->input
, rec
->length
) <= 0
1271 || EVP_DigestSignFinal(mac_ctx
, md
, &md_size
) <= 0) {
1272 EVP_MD_CTX_free(hmac
);
1277 EVP_MD_CTX_free(hmac
);
1280 fprintf(stderr
, "seq=");
1283 for (z
= 0; z
< 8; z
++)
1284 fprintf(stderr
, "%02X ", seq
[z
]);
1285 fprintf(stderr
, "\n");
1287 fprintf(stderr
, "rec=");
1290 for (z
= 0; z
< rec
->length
; z
++)
1291 fprintf(stderr
, "%02X ", rec
->data
[z
]);
1292 fprintf(stderr
, "\n");
1296 if (!SSL_IS_DTLS(ssl
)) {
1297 for (i
= 7; i
>= 0; i
--) {
1306 for (z
= 0; z
< md_size
; z
++)
1307 fprintf(stderr
, "%02X ", md
[z
]);
1308 fprintf(stderr
, "\n");
1315 * ssl3_cbc_remove_padding removes padding from the decrypted, SSLv3, CBC
1316 * record in |rec| by updating |rec->length| in constant time.
1318 * block_size: the block size of the cipher used to encrypt the record.
1320 * 0: (in non-constant time) if the record is publicly invalid.
1321 * 1: if the padding was valid
1324 int ssl3_cbc_remove_padding(SSL3_RECORD
*rec
,
1325 size_t block_size
, size_t mac_size
)
1327 size_t padding_length
;
1329 const size_t overhead
= 1 /* padding length byte */ + mac_size
;
1332 * These lengths are all public so we can test them in non-constant time.
1334 if (overhead
> rec
->length
)
1337 padding_length
= rec
->data
[rec
->length
- 1];
1338 good
= constant_time_ge_s(rec
->length
, padding_length
+ overhead
);
1339 /* SSLv3 requires that the padding is minimal. */
1340 good
&= constant_time_ge_s(block_size
, padding_length
+ 1);
1341 rec
->length
-= good
& (padding_length
+ 1);
1342 return constant_time_select_int_s(good
, 1, -1);
1346 * tls1_cbc_remove_padding removes the CBC padding from the decrypted, TLS, CBC
1347 * record in |rec| in constant time and returns 1 if the padding is valid and
1348 * -1 otherwise. It also removes any explicit IV from the start of the record
1349 * without leaking any timing about whether there was enough space after the
1350 * padding was removed.
1352 * block_size: the block size of the cipher used to encrypt the record.
1354 * 0: (in non-constant time) if the record is publicly invalid.
1355 * 1: if the padding was valid
1358 int tls1_cbc_remove_padding(const SSL
*s
,
1360 size_t block_size
, size_t mac_size
)
1363 size_t padding_length
, to_check
, i
;
1364 const size_t overhead
= 1 /* padding length byte */ + mac_size
;
1365 /* Check if version requires explicit IV */
1366 if (SSL_USE_EXPLICIT_IV(s
)) {
1368 * These lengths are all public so we can test them in non-constant
1371 if (overhead
+ block_size
> rec
->length
)
1373 /* We can now safely skip explicit IV */
1374 rec
->data
+= block_size
;
1375 rec
->input
+= block_size
;
1376 rec
->length
-= block_size
;
1377 rec
->orig_len
-= block_size
;
1378 } else if (overhead
> rec
->length
)
1381 padding_length
= rec
->data
[rec
->length
- 1];
1383 if (EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(s
->enc_read_ctx
)) &
1384 EVP_CIPH_FLAG_AEAD_CIPHER
) {
1385 /* padding is already verified */
1386 rec
->length
-= padding_length
+ 1;
1390 good
= constant_time_ge_s(rec
->length
, overhead
+ padding_length
);
1392 * The padding consists of a length byte at the end of the record and
1393 * then that many bytes of padding, all with the same value as the length
1394 * byte. Thus, with the length byte included, there are i+1 bytes of
1395 * padding. We can't check just |padding_length+1| bytes because that
1396 * leaks decrypted information. Therefore we always have to check the
1397 * maximum amount of padding possible. (Again, the length of the record
1398 * is public information so we can use it.)
1400 to_check
= 256; /* maximum amount of padding, inc length byte. */
1401 if (to_check
> rec
->length
)
1402 to_check
= rec
->length
;
1404 for (i
= 0; i
< to_check
; i
++) {
1405 unsigned char mask
= constant_time_ge_8_s(padding_length
, i
);
1406 unsigned char b
= rec
->data
[rec
->length
- 1 - i
];
1408 * The final |padding_length+1| bytes should all have the value
1409 * |padding_length|. Therefore the XOR should be zero.
1411 good
&= ~(mask
& (padding_length
^ b
));
1415 * If any of the final |padding_length+1| bytes had the wrong value, one
1416 * or more of the lower eight bits of |good| will be cleared.
1418 good
= constant_time_eq_s(0xff, good
& 0xff);
1419 rec
->length
-= good
& (padding_length
+ 1);
1421 return constant_time_select_int_s(good
, 1, -1);
1425 * ssl3_cbc_copy_mac copies |md_size| bytes from the end of |rec| to |out| in
1426 * constant time (independent of the concrete value of rec->length, which may
1427 * vary within a 256-byte window).
1429 * ssl3_cbc_remove_padding or tls1_cbc_remove_padding must be called prior to
1433 * rec->orig_len >= md_size
1434 * md_size <= EVP_MAX_MD_SIZE
1436 * If CBC_MAC_ROTATE_IN_PLACE is defined then the rotation is performed with
1437 * variable accesses in a 64-byte-aligned buffer. Assuming that this fits into
1438 * a single or pair of cache-lines, then the variable memory accesses don't
1439 * actually affect the timing. CPUs with smaller cache-lines [if any] are
1440 * not multi-core and are not considered vulnerable to cache-timing attacks.
1442 #define CBC_MAC_ROTATE_IN_PLACE
1444 int ssl3_cbc_copy_mac(unsigned char *out
,
1445 const SSL3_RECORD
*rec
, size_t md_size
)
1447 #if defined(CBC_MAC_ROTATE_IN_PLACE)
1448 unsigned char rotated_mac_buf
[64 + EVP_MAX_MD_SIZE
];
1449 unsigned char *rotated_mac
;
1451 unsigned char rotated_mac
[EVP_MAX_MD_SIZE
];
1455 * mac_end is the index of |rec->data| just after the end of the MAC.
1457 size_t mac_end
= rec
->length
;
1458 size_t mac_start
= mac_end
- md_size
;
1461 * scan_start contains the number of bytes that we can ignore because the
1462 * MAC's position can only vary by 255 bytes.
1464 size_t scan_start
= 0;
1466 size_t rotate_offset
;
1468 if (!ossl_assert(rec
->orig_len
>= md_size
1469 && md_size
<= EVP_MAX_MD_SIZE
))
1472 #if defined(CBC_MAC_ROTATE_IN_PLACE)
1473 rotated_mac
= rotated_mac_buf
+ ((0 - (size_t)rotated_mac_buf
) & 63);
1476 /* This information is public so it's safe to branch based on it. */
1477 if (rec
->orig_len
> md_size
+ 255 + 1)
1478 scan_start
= rec
->orig_len
- (md_size
+ 255 + 1);
1482 memset(rotated_mac
, 0, md_size
);
1483 for (i
= scan_start
, j
= 0; i
< rec
->orig_len
; i
++) {
1484 size_t mac_started
= constant_time_eq_s(i
, mac_start
);
1485 size_t mac_ended
= constant_time_lt_s(i
, mac_end
);
1486 unsigned char b
= rec
->data
[i
];
1488 in_mac
|= mac_started
;
1489 in_mac
&= mac_ended
;
1490 rotate_offset
|= j
& mac_started
;
1491 rotated_mac
[j
++] |= b
& in_mac
;
1492 j
&= constant_time_lt_s(j
, md_size
);
1495 /* Now rotate the MAC */
1496 #if defined(CBC_MAC_ROTATE_IN_PLACE)
1498 for (i
= 0; i
< md_size
; i
++) {
1499 /* in case cache-line is 32 bytes, touch second line */
1500 ((volatile unsigned char *)rotated_mac
)[rotate_offset
^ 32];
1501 out
[j
++] = rotated_mac
[rotate_offset
++];
1502 rotate_offset
&= constant_time_lt_s(rotate_offset
, md_size
);
1505 memset(out
, 0, md_size
);
1506 rotate_offset
= md_size
- rotate_offset
;
1507 rotate_offset
&= constant_time_lt_s(rotate_offset
, md_size
);
1508 for (i
= 0; i
< md_size
; i
++) {
1509 for (j
= 0; j
< md_size
; j
++)
1510 out
[j
] |= rotated_mac
[i
] & constant_time_eq_8_s(j
, rotate_offset
);
1512 rotate_offset
&= constant_time_lt_s(rotate_offset
, md_size
);
1519 int dtls1_process_record(SSL
*s
, DTLS1_BITMAP
*bitmap
)
1527 unsigned char md
[EVP_MAX_MD_SIZE
];
1529 rr
= RECORD_LAYER_get_rrec(&s
->rlayer
);
1533 * At this point, s->packet_length == SSL3_RT_HEADER_LNGTH + rr->length,
1534 * and we have that many bytes in s->packet
1536 rr
->input
= &(RECORD_LAYER_get_packet(&s
->rlayer
)[DTLS1_RT_HEADER_LENGTH
]);
1539 * ok, we can now read from 's->packet' data into 'rr' rr->input points
1540 * at rr->length bytes, which need to be copied into rr->data by either
1541 * the decryption or by the decompression When the data is 'copied' into
1542 * the rr->data buffer, rr->input will be pointed at the new buffer
1546 * We now have - encrypted [ MAC [ compressed [ plain ] ] ] rr->length
1547 * bytes of encrypted compressed stuff.
1550 /* check is not needed I believe */
1551 if (rr
->length
> SSL3_RT_MAX_ENCRYPTED_LENGTH
) {
1552 al
= SSL_AD_RECORD_OVERFLOW
;
1553 SSLerr(SSL_F_DTLS1_PROCESS_RECORD
, SSL_R_ENCRYPTED_LENGTH_TOO_LONG
);
1557 /* decrypt in place in 'rr->input' */
1558 rr
->data
= rr
->input
;
1559 rr
->orig_len
= rr
->length
;
1561 if (SSL_READ_ETM(s
) && s
->read_hash
) {
1563 mac_size
= EVP_MD_CTX_size(s
->read_hash
);
1564 if (!ossl_assert(mac_size
<= EVP_MAX_MD_SIZE
)) {
1565 al
= SSL_AD_INTERNAL_ERROR
;
1566 SSLerr(SSL_F_DTLS1_PROCESS_RECORD
, ERR_R_INTERNAL_ERROR
);
1569 if (rr
->orig_len
< mac_size
) {
1570 al
= SSL_AD_DECODE_ERROR
;
1571 SSLerr(SSL_F_DTLS1_PROCESS_RECORD
, SSL_R_LENGTH_TOO_SHORT
);
1574 rr
->length
-= mac_size
;
1575 mac
= rr
->data
+ rr
->length
;
1576 i
= s
->method
->ssl3_enc
->mac(s
, rr
, md
, 0 /* not send */ );
1577 if (i
== 0 || CRYPTO_memcmp(md
, mac
, (size_t)mac_size
) != 0) {
1578 al
= SSL_AD_BAD_RECORD_MAC
;
1579 SSLerr(SSL_F_DTLS1_PROCESS_RECORD
,
1580 SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC
);
1585 enc_err
= s
->method
->ssl3_enc
->enc(s
, rr
, 1, 0);
1588 * 0: (in non-constant time) if the record is publically invalid.
1589 * 1: if the padding is valid
1590 * -1: if the padding is invalid
1593 /* For DTLS we simply ignore bad packets. */
1595 RECORD_LAYER_reset_packet_length(&s
->rlayer
);
1599 printf("dec %ld\n", rr
->length
);
1602 for (z
= 0; z
< rr
->length
; z
++)
1603 printf("%02X%c", rr
->data
[z
], ((z
+ 1) % 16) ? ' ' : '\n');
1608 /* r->length is now the compressed data plus mac */
1609 if ((sess
!= NULL
) && !SSL_READ_ETM(s
) &&
1610 (s
->enc_read_ctx
!= NULL
) && (EVP_MD_CTX_md(s
->read_hash
) != NULL
)) {
1611 /* s->read_hash != NULL => mac_size != -1 */
1612 unsigned char *mac
= NULL
;
1613 unsigned char mac_tmp
[EVP_MAX_MD_SIZE
];
1615 /* TODO(size_t): Convert this to do size_t properly */
1616 imac_size
= EVP_MD_CTX_size(s
->read_hash
);
1617 if (imac_size
< 0) {
1618 al
= SSL_AD_INTERNAL_ERROR
;
1619 SSLerr(SSL_F_DTLS1_PROCESS_RECORD
, ERR_LIB_EVP
);
1622 mac_size
= (size_t)imac_size
;
1623 if (!ossl_assert(mac_size
<= EVP_MAX_MD_SIZE
)) {
1624 al
= SSL_AD_INTERNAL_ERROR
;
1625 SSLerr(SSL_F_DTLS1_PROCESS_RECORD
, ERR_R_INTERNAL_ERROR
);
1630 * orig_len is the length of the record before any padding was
1631 * removed. This is public information, as is the MAC in use,
1632 * therefore we can safely process the record in a different amount
1633 * of time if it's too short to possibly contain a MAC.
1635 if (rr
->orig_len
< mac_size
||
1636 /* CBC records must have a padding length byte too. */
1637 (EVP_CIPHER_CTX_mode(s
->enc_read_ctx
) == EVP_CIPH_CBC_MODE
&&
1638 rr
->orig_len
< mac_size
+ 1)) {
1639 al
= SSL_AD_DECODE_ERROR
;
1640 SSLerr(SSL_F_DTLS1_PROCESS_RECORD
, SSL_R_LENGTH_TOO_SHORT
);
1644 if (EVP_CIPHER_CTX_mode(s
->enc_read_ctx
) == EVP_CIPH_CBC_MODE
) {
1646 * We update the length so that the TLS header bytes can be
1647 * constructed correctly but we need to extract the MAC in
1648 * constant time from within the record, without leaking the
1649 * contents of the padding bytes.
1652 if (!ssl3_cbc_copy_mac(mac_tmp
, rr
, mac_size
)) {
1653 al
= SSL_AD_INTERNAL_ERROR
;
1654 SSLerr(SSL_F_DTLS1_PROCESS_RECORD
, ERR_R_INTERNAL_ERROR
);
1657 rr
->length
-= mac_size
;
1660 * In this case there's no padding, so |rec->orig_len| equals
1661 * |rec->length| and we checked that there's enough bytes for
1664 rr
->length
-= mac_size
;
1665 mac
= &rr
->data
[rr
->length
];
1668 i
= s
->method
->ssl3_enc
->mac(s
, rr
, md
, 0 /* not send */ );
1669 if (i
== 0 || mac
== NULL
1670 || CRYPTO_memcmp(md
, mac
, mac_size
) != 0)
1672 if (rr
->length
> SSL3_RT_MAX_COMPRESSED_LENGTH
+ mac_size
)
1677 /* decryption failed, silently discard message */
1679 RECORD_LAYER_reset_packet_length(&s
->rlayer
);
1683 /* r->length is now just compressed */
1684 if (s
->expand
!= NULL
) {
1685 if (rr
->length
> SSL3_RT_MAX_COMPRESSED_LENGTH
) {
1686 al
= SSL_AD_RECORD_OVERFLOW
;
1687 SSLerr(SSL_F_DTLS1_PROCESS_RECORD
,
1688 SSL_R_COMPRESSED_LENGTH_TOO_LONG
);
1691 if (!ssl3_do_uncompress(s
, rr
)) {
1692 al
= SSL_AD_DECOMPRESSION_FAILURE
;
1693 SSLerr(SSL_F_DTLS1_PROCESS_RECORD
, SSL_R_BAD_DECOMPRESSION
);
1698 if (rr
->length
> SSL3_RT_MAX_PLAIN_LENGTH
) {
1699 al
= SSL_AD_RECORD_OVERFLOW
;
1700 SSLerr(SSL_F_DTLS1_PROCESS_RECORD
, SSL_R_DATA_LENGTH_TOO_LONG
);
1706 * So at this point the following is true
1707 * ssl->s3->rrec.type is the type of record
1708 * ssl->s3->rrec.length == number of bytes in record
1709 * ssl->s3->rrec.off == offset to first valid byte
1710 * ssl->s3->rrec.data == where to take bytes from, increment
1714 /* we have pulled in a full packet so zero things */
1715 RECORD_LAYER_reset_packet_length(&s
->rlayer
);
1717 /* Mark receipt of record. */
1718 dtls1_record_bitmap_update(s
, bitmap
);
1723 ssl3_send_alert(s
, SSL3_AL_FATAL
, al
);
1729 * Retrieve a buffered record that belongs to the current epoch, i.e. processed
1731 #define dtls1_get_processed_record(s) \
1732 dtls1_retrieve_buffered_record((s), \
1733 &(DTLS_RECORD_LAYER_get_processed_rcds(&s->rlayer)))
1736 * Call this to get a new input record.
1737 * It will return <= 0 if more data is needed, normally due to an error
1738 * or non-blocking IO.
1739 * When it finishes, one packet has been decoded and can be found in
1740 * ssl->s3->rrec.type - is the type of record
1741 * ssl->s3->rrec.data, - data
1742 * ssl->s3->rrec.length, - number of bytes
1744 /* used only by dtls1_read_bytes */
1745 int dtls1_get_record(SSL
*s
)
1747 int ssl_major
, ssl_minor
;
1751 unsigned char *p
= NULL
;
1752 unsigned short version
;
1753 DTLS1_BITMAP
*bitmap
;
1754 unsigned int is_next_epoch
;
1756 rr
= RECORD_LAYER_get_rrec(&s
->rlayer
);
1760 * The epoch may have changed. If so, process all the pending records.
1761 * This is a non-blocking operation.
1763 if (!dtls1_process_buffered_records(s
))
1766 /* if we're renegotiating, then there may be buffered records */
1767 if (dtls1_get_processed_record(s
))
1770 /* get something from the wire */
1772 /* check if we have the header */
1773 if ((RECORD_LAYER_get_rstate(&s
->rlayer
) != SSL_ST_READ_BODY
) ||
1774 (RECORD_LAYER_get_packet_length(&s
->rlayer
) < DTLS1_RT_HEADER_LENGTH
)) {
1775 rret
= ssl3_read_n(s
, DTLS1_RT_HEADER_LENGTH
,
1776 SSL3_BUFFER_get_len(&s
->rlayer
.rbuf
), 0, 1, &n
);
1777 /* read timeout is handled by dtls1_read_bytes */
1779 return rret
; /* error or non-blocking */
1781 /* this packet contained a partial record, dump it */
1782 if (RECORD_LAYER_get_packet_length(&s
->rlayer
) !=
1783 DTLS1_RT_HEADER_LENGTH
) {
1784 RECORD_LAYER_reset_packet_length(&s
->rlayer
);
1788 RECORD_LAYER_set_rstate(&s
->rlayer
, SSL_ST_READ_BODY
);
1790 p
= RECORD_LAYER_get_packet(&s
->rlayer
);
1792 if (s
->msg_callback
)
1793 s
->msg_callback(0, 0, SSL3_RT_HEADER
, p
, DTLS1_RT_HEADER_LENGTH
,
1794 s
, s
->msg_callback_arg
);
1796 /* Pull apart the header into the DTLS1_RECORD */
1800 version
= (ssl_major
<< 8) | ssl_minor
;
1802 /* sequence number is 64 bits, with top 2 bytes = epoch */
1805 memcpy(&(RECORD_LAYER_get_read_sequence(&s
->rlayer
)[2]), p
, 6);
1810 /* Lets check version */
1811 if (!s
->first_packet
) {
1812 if (version
!= s
->version
) {
1813 /* unexpected version, silently discard */
1815 RECORD_LAYER_reset_packet_length(&s
->rlayer
);
1820 if ((version
& 0xff00) != (s
->version
& 0xff00)) {
1821 /* wrong version, silently discard record */
1823 RECORD_LAYER_reset_packet_length(&s
->rlayer
);
1827 if (rr
->length
> SSL3_RT_MAX_ENCRYPTED_LENGTH
) {
1828 /* record too long, silently discard it */
1830 RECORD_LAYER_reset_packet_length(&s
->rlayer
);
1834 /* If received packet overflows own-client Max Fragment Length setting */
1835 if (s
->session
!= NULL
&& USE_MAX_FRAGMENT_LENGTH_EXT(s
->session
)
1836 && rr
->length
> GET_MAX_FRAGMENT_LENGTH(s
->session
)) {
1837 /* record too long, silently discard it */
1839 RECORD_LAYER_reset_packet_length(&s
->rlayer
);
1843 /* now s->rlayer.rstate == SSL_ST_READ_BODY */
1846 /* s->rlayer.rstate == SSL_ST_READ_BODY, get and decode the data */
1849 RECORD_LAYER_get_packet_length(&s
->rlayer
) - DTLS1_RT_HEADER_LENGTH
) {
1850 /* now s->packet_length == DTLS1_RT_HEADER_LENGTH */
1852 rret
= ssl3_read_n(s
, more
, more
, 1, 1, &n
);
1853 /* this packet contained a partial record, dump it */
1854 if (rret
<= 0 || n
!= more
) {
1856 RECORD_LAYER_reset_packet_length(&s
->rlayer
);
1861 * now n == rr->length, and s->packet_length ==
1862 * DTLS1_RT_HEADER_LENGTH + rr->length
1865 /* set state for later operations */
1866 RECORD_LAYER_set_rstate(&s
->rlayer
, SSL_ST_READ_HEADER
);
1868 /* match epochs. NULL means the packet is dropped on the floor */
1869 bitmap
= dtls1_get_bitmap(s
, rr
, &is_next_epoch
);
1870 if (bitmap
== NULL
) {
1872 RECORD_LAYER_reset_packet_length(&s
->rlayer
); /* dump this record */
1873 goto again
; /* get another record */
1875 #ifndef OPENSSL_NO_SCTP
1876 /* Only do replay check if no SCTP bio */
1877 if (!BIO_dgram_is_sctp(SSL_get_rbio(s
))) {
1879 /* Check whether this is a repeat, or aged record. */
1881 * TODO: Does it make sense to have replay protection in epoch 0 where
1882 * we have no integrity negotiated yet?
1884 if (!dtls1_record_replay_check(s
, bitmap
)) {
1886 RECORD_LAYER_reset_packet_length(&s
->rlayer
); /* dump this record */
1887 goto again
; /* get another record */
1889 #ifndef OPENSSL_NO_SCTP
1893 /* just read a 0 length packet */
1894 if (rr
->length
== 0)
1898 * If this record is from the next epoch (either HM or ALERT), and a
1899 * handshake is currently in progress, buffer it since it cannot be
1900 * processed at this time.
1902 if (is_next_epoch
) {
1903 if ((SSL_in_init(s
) || ossl_statem_get_in_handshake(s
))) {
1904 if (dtls1_buffer_record
1905 (s
, &(DTLS_RECORD_LAYER_get_unprocessed_rcds(&s
->rlayer
)),
1910 RECORD_LAYER_reset_packet_length(&s
->rlayer
);
1914 if (!dtls1_process_record(s
, bitmap
)) {
1916 RECORD_LAYER_reset_packet_length(&s
->rlayer
); /* dump this record */
1917 goto again
; /* get another record */