2 * Copyright 1995-2018 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 send)
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 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_EARLY_DATA_COUNT_OK,
118 ERR_R_INTERNAL_ERROR);
121 sess = s->psksession;
124 || (s->hit && sess->ext.max_early_data < s->max_early_data))
125 max_early_data = sess->ext.max_early_data;
127 if (max_early_data == 0) {
128 SSLfatal(s, send ? SSL_AD_INTERNAL_ERROR : SSL_AD_UNEXPECTED_MESSAGE,
129 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) {
137 SSLfatal(s, send ? SSL_AD_INTERNAL_ERROR : SSL_AD_UNEXPECTED_MESSAGE,
138 SSL_F_EARLY_DATA_COUNT_OK, SSL_R_TOO_MUCH_EARLY_DATA);
141 s->early_data_count += length;
147 * MAX_EMPTY_RECORDS defines the number of consecutive, empty records that
148 * will be processed per call to ssl3_get_record. Without this limit an
149 * attacker could send empty records at a faster rate than we can process and
150 * cause ssl3_get_record to loop forever.
152 #define MAX_EMPTY_RECORDS 32
154 #define SSL2_RT_HEADER_LENGTH 2
156 * Call this to get new input records.
157 * It will return <= 0 if more data is needed, normally due to an error
158 * or non-blocking IO.
159 * When it finishes, |numrpipes| records have been decoded. For each record 'i':
160 * rr[i].type - is the type of record
162 * rr[i].length, - number of bytes
163 * Multiple records will only be returned if the record types are all
164 * SSL3_RT_APPLICATION_DATA. The number of records returned will always be <=
167 /* used only by ssl3_read_bytes */
168 int ssl3_get_record(SSL *s)
173 SSL3_RECORD *rr, *thisrr;
177 unsigned char md[EVP_MAX_MD_SIZE];
178 unsigned int version;
181 size_t num_recs = 0, max_recs, j;
182 PACKET pkt, sslv2pkt;
183 size_t first_rec_len;
185 rr = RECORD_LAYER_get_rrec(&s->rlayer);
186 rbuf = RECORD_LAYER_get_rbuf(&s->rlayer);
187 max_recs = s->max_pipelines;
193 thisrr = &rr[num_recs];
195 /* check if we have the header */
196 if ((RECORD_LAYER_get_rstate(&s->rlayer) != SSL_ST_READ_BODY) ||
197 (RECORD_LAYER_get_packet_length(&s->rlayer)
198 < SSL3_RT_HEADER_LENGTH)) {
202 rret = ssl3_read_n(s, SSL3_RT_HEADER_LENGTH,
203 SSL3_BUFFER_get_len(rbuf), 0,
204 num_recs == 0 ? 1 : 0, &n);
206 return rret; /* error or non-blocking */
207 RECORD_LAYER_set_rstate(&s->rlayer, SSL_ST_READ_BODY);
209 p = RECORD_LAYER_get_packet(&s->rlayer);
210 if (!PACKET_buf_init(&pkt, RECORD_LAYER_get_packet(&s->rlayer),
211 RECORD_LAYER_get_packet_length(&s->rlayer))) {
212 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_SSL3_GET_RECORD,
213 ERR_R_INTERNAL_ERROR);
217 if (!PACKET_get_net_2_len(&sslv2pkt, &sslv2len)
218 || !PACKET_get_1(&sslv2pkt, &type)) {
219 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL3_GET_RECORD,
220 ERR_R_INTERNAL_ERROR);
224 * The first record received by the server may be a V2ClientHello.
226 if (s->server && RECORD_LAYER_is_first_record(&s->rlayer)
227 && (sslv2len & 0x8000) != 0
228 && (type == SSL2_MT_CLIENT_HELLO)) {
232 * |num_recs| here will actually always be 0 because
233 * |num_recs > 0| only ever occurs when we are processing
234 * multiple app data records - which we know isn't the case here
235 * because it is an SSLv2ClientHello. We keep it using
236 * |num_recs| for the sake of consistency
238 thisrr->type = SSL3_RT_HANDSHAKE;
239 thisrr->rec_version = SSL2_VERSION;
241 thisrr->length = sslv2len & 0x7fff;
243 if (thisrr->length > SSL3_BUFFER_get_len(rbuf)
244 - SSL2_RT_HEADER_LENGTH) {
245 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD,
246 SSL_R_PACKET_LENGTH_TOO_LONG);
250 if (thisrr->length < MIN_SSL2_RECORD_LEN) {
251 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL3_GET_RECORD,
252 SSL_R_LENGTH_TOO_SHORT);
256 /* SSLv3+ style record */
258 s->msg_callback(0, 0, SSL3_RT_HEADER, p, 5, s,
259 s->msg_callback_arg);
261 /* Pull apart the header into the SSL3_RECORD */
262 if (!PACKET_get_1(&pkt, &type)
263 || !PACKET_get_net_2(&pkt, &version)
264 || !PACKET_get_net_2_len(&pkt, &thisrr->length)) {
265 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL3_GET_RECORD,
266 ERR_R_INTERNAL_ERROR);
270 thisrr->rec_version = version;
273 * Lets check version. In TLSv1.3 we only check this field
274 * when encryption is occurring (see later check). For the
275 * ServerHello after an HRR we haven't actually selected TLSv1.3
276 * yet, but we still treat it as TLSv1.3, so we must check for
279 if (!s->first_packet && !SSL_IS_TLS13(s)
280 && s->hello_retry_request != SSL_HRR_PENDING
281 && version != (unsigned int)s->version) {
282 if ((s->version & 0xFF00) == (version & 0xFF00)
283 && !s->enc_write_ctx && !s->write_hash) {
284 if (thisrr->type == SSL3_RT_ALERT) {
286 * The record is using an incorrect version number,
287 * but what we've got appears to be an alert. We
288 * haven't read the body yet to check whether its a
289 * fatal or not - but chances are it is. We probably
290 * shouldn't send a fatal alert back. We'll just
293 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_SSL3_GET_RECORD,
294 SSL_R_WRONG_VERSION_NUMBER);
298 * Send back error using their minor version number :-)
300 s->version = (unsigned short)version;
302 SSLfatal(s, SSL_AD_PROTOCOL_VERSION, SSL_F_SSL3_GET_RECORD,
303 SSL_R_WRONG_VERSION_NUMBER);
307 if ((version >> 8) != SSL3_VERSION_MAJOR) {
308 if (RECORD_LAYER_is_first_record(&s->rlayer)) {
309 /* Go back to start of packet, look at the five bytes
311 p = RECORD_LAYER_get_packet(&s->rlayer);
312 if (strncmp((char *)p, "GET ", 4) == 0 ||
313 strncmp((char *)p, "POST ", 5) == 0 ||
314 strncmp((char *)p, "HEAD ", 5) == 0 ||
315 strncmp((char *)p, "PUT ", 4) == 0) {
316 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_SSL3_GET_RECORD,
319 } else if (strncmp((char *)p, "CONNE", 5) == 0) {
320 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_SSL3_GET_RECORD,
321 SSL_R_HTTPS_PROXY_REQUEST);
325 /* Doesn't look like TLS - don't send an alert */
326 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_SSL3_GET_RECORD,
327 SSL_R_WRONG_VERSION_NUMBER);
330 SSLfatal(s, SSL_AD_PROTOCOL_VERSION,
331 SSL_F_SSL3_GET_RECORD,
332 SSL_R_WRONG_VERSION_NUMBER);
337 if (SSL_IS_TLS13(s) && s->enc_read_ctx != NULL) {
338 if (thisrr->type != SSL3_RT_APPLICATION_DATA
339 && (thisrr->type != SSL3_RT_CHANGE_CIPHER_SPEC
340 || !SSL_IS_FIRST_HANDSHAKE(s))) {
341 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE,
342 SSL_F_SSL3_GET_RECORD, SSL_R_BAD_RECORD_TYPE);
345 if (thisrr->rec_version != TLS1_2_VERSION) {
346 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL3_GET_RECORD,
347 SSL_R_WRONG_VERSION_NUMBER);
353 SSL3_BUFFER_get_len(rbuf) - SSL3_RT_HEADER_LENGTH) {
354 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD,
355 SSL_R_PACKET_LENGTH_TOO_LONG);
360 /* now s->rlayer.rstate == SSL_ST_READ_BODY */
363 if (SSL_IS_TLS13(s)) {
364 if (thisrr->length > SSL3_RT_MAX_TLS13_ENCRYPTED_LENGTH) {
365 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD,
366 SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
370 size_t len = SSL3_RT_MAX_ENCRYPTED_LENGTH;
372 #ifndef OPENSSL_NO_COMP
374 * If OPENSSL_NO_COMP is defined then SSL3_RT_MAX_ENCRYPTED_LENGTH
375 * does not include the compression overhead anyway.
377 if (s->expand == NULL)
378 len -= SSL3_RT_MAX_COMPRESSED_OVERHEAD;
381 if (thisrr->length > len) {
382 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD,
383 SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
389 * s->rlayer.rstate == SSL_ST_READ_BODY, get and decode the data.
390 * Calculate how much more data we need to read for the rest of the
393 if (thisrr->rec_version == SSL2_VERSION) {
394 more = thisrr->length + SSL2_RT_HEADER_LENGTH
395 - SSL3_RT_HEADER_LENGTH;
397 more = thisrr->length;
400 /* now s->packet_length == SSL3_RT_HEADER_LENGTH */
402 rret = ssl3_read_n(s, more, more, 1, 0, &n);
404 return rret; /* error or non-blocking io */
407 /* set state for later operations */
408 RECORD_LAYER_set_rstate(&s->rlayer, SSL_ST_READ_HEADER);
411 * At this point, s->packet_length == SSL3_RT_HEADER_LENGTH
412 * + thisrr->length, or s->packet_length == SSL2_RT_HEADER_LENGTH
413 * + thisrr->length and we have that many bytes in s->packet
415 if (thisrr->rec_version == SSL2_VERSION) {
417 &(RECORD_LAYER_get_packet(&s->rlayer)[SSL2_RT_HEADER_LENGTH]);
420 &(RECORD_LAYER_get_packet(&s->rlayer)[SSL3_RT_HEADER_LENGTH]);
424 * ok, we can now read from 's->packet' data into 'thisrr' thisrr->input
425 * points at thisrr->length bytes, which need to be copied into
426 * thisrr->data by either the decryption or by the decompression When
427 * the data is 'copied' into the thisrr->data buffer, thisrr->input will
428 * be pointed at the new buffer
432 * We now have - encrypted [ MAC [ compressed [ plain ] ] ]
433 * thisrr->length bytes of encrypted compressed stuff.
436 /* decrypt in place in 'thisrr->input' */
437 thisrr->data = thisrr->input;
438 thisrr->orig_len = thisrr->length;
440 /* Mark this record as not read by upper layers yet */
445 /* we have pulled in a full packet so zero things */
446 RECORD_LAYER_reset_packet_length(&s->rlayer);
447 RECORD_LAYER_clear_first_record(&s->rlayer);
448 } while (num_recs < max_recs
449 && thisrr->type == SSL3_RT_APPLICATION_DATA
450 && SSL_USE_EXPLICIT_IV(s)
451 && s->enc_read_ctx != NULL
452 && (EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(s->enc_read_ctx))
453 & EVP_CIPH_FLAG_PIPELINE)
454 && ssl3_record_app_data_waiting(s));
457 && thisrr->type == SSL3_RT_CHANGE_CIPHER_SPEC
458 && (SSL_IS_TLS13(s) || s->hello_retry_request != SSL_HRR_NONE)
459 && SSL_IS_FIRST_HANDSHAKE(s)) {
461 * CCS messages must be exactly 1 byte long, containing the value 0x01
463 if (thisrr->length != 1 || thisrr->data[0] != 0x01) {
464 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_SSL3_GET_RECORD,
465 SSL_R_INVALID_CCS_MESSAGE);
469 * CCS messages are ignored in TLSv1.3. We treat it like an empty
472 thisrr->type = SSL3_RT_HANDSHAKE;
473 RECORD_LAYER_inc_empty_record_count(&s->rlayer);
474 if (RECORD_LAYER_get_empty_record_count(&s->rlayer)
475 > MAX_EMPTY_RECORDS) {
476 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_F_SSL3_GET_RECORD,
477 SSL_R_UNEXPECTED_CCS_MESSAGE);
481 RECORD_LAYER_set_numrpipes(&s->rlayer, 1);
487 * If in encrypt-then-mac mode calculate mac from encrypted record. All
488 * the details below are public so no timing details can leak.
490 if (SSL_READ_ETM(s) && s->read_hash) {
492 /* TODO(size_t): convert this to do size_t properly */
493 imac_size = EVP_MD_CTX_size(s->read_hash);
494 if (!ossl_assert(imac_size >= 0 && imac_size <= EVP_MAX_MD_SIZE)) {
495 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_SSL3_GET_RECORD,
499 mac_size = (size_t)imac_size;
500 for (j = 0; j < num_recs; j++) {
503 if (thisrr->length < mac_size) {
504 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL3_GET_RECORD,
505 SSL_R_LENGTH_TOO_SHORT);
508 thisrr->length -= mac_size;
509 mac = thisrr->data + thisrr->length;
510 i = s->method->ssl3_enc->mac(s, thisrr, md, 0 /* not send */ );
511 if (i == 0 || CRYPTO_memcmp(md, mac, mac_size) != 0) {
512 SSLfatal(s, SSL_AD_BAD_RECORD_MAC, SSL_F_SSL3_GET_RECORD,
513 SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
519 first_rec_len = rr[0].length;
521 enc_err = s->method->ssl3_enc->enc(s, rr, num_recs, 0);
525 * 0: (in non-constant time) if the record is publicly invalid.
526 * 1: if the padding is valid
527 * -1: if the padding is invalid
530 if (ossl_statem_in_error(s)) {
531 /* SSLfatal() already got called */
534 if (num_recs == 1 && ossl_statem_skip_early_data(s)) {
536 * Valid early_data that we cannot decrypt might fail here as
537 * publicly invalid. We treat it like an empty record.
542 if (!early_data_count_ok(s, thisrr->length,
543 EARLY_DATA_CIPHERTEXT_OVERHEAD, 0)) {
544 /* SSLfatal() already called */
550 RECORD_LAYER_set_numrpipes(&s->rlayer, 1);
551 RECORD_LAYER_reset_read_sequence(&s->rlayer);
554 SSLfatal(s, SSL_AD_DECRYPTION_FAILED, SSL_F_SSL3_GET_RECORD,
555 SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
559 printf("dec %lu\n", (unsigned long)rr[0].length);
562 for (z = 0; z < rr[0].length; z++)
563 printf("%02X%c", rr[0].data[z], ((z + 1) % 16) ? ' ' : '\n');
568 /* r->length is now the compressed data plus mac */
569 if ((sess != NULL) &&
570 (s->enc_read_ctx != NULL) &&
571 (!SSL_READ_ETM(s) && EVP_MD_CTX_md(s->read_hash) != NULL)) {
572 /* s->read_hash != NULL => mac_size != -1 */
573 unsigned char *mac = NULL;
574 unsigned char mac_tmp[EVP_MAX_MD_SIZE];
576 mac_size = EVP_MD_CTX_size(s->read_hash);
577 if (!ossl_assert(mac_size <= EVP_MAX_MD_SIZE)) {
578 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_SSL3_GET_RECORD,
579 ERR_R_INTERNAL_ERROR);
583 for (j = 0; j < num_recs; j++) {
586 * orig_len is the length of the record before any padding was
587 * removed. This is public information, as is the MAC in use,
588 * therefore we can safely process the record in a different amount
589 * of time if it's too short to possibly contain a MAC.
591 if (thisrr->orig_len < mac_size ||
592 /* CBC records must have a padding length byte too. */
593 (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
594 thisrr->orig_len < mac_size + 1)) {
595 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL3_GET_RECORD,
596 SSL_R_LENGTH_TOO_SHORT);
600 if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE) {
602 * We update the length so that the TLS header bytes can be
603 * constructed correctly but we need to extract the MAC in
604 * constant time from within the record, without leaking the
605 * contents of the padding bytes.
608 if (!ssl3_cbc_copy_mac(mac_tmp, thisrr, mac_size)) {
609 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_SSL3_GET_RECORD,
610 ERR_R_INTERNAL_ERROR);
613 thisrr->length -= mac_size;
616 * In this case there's no padding, so |rec->orig_len| equals
617 * |rec->length| and we checked that there's enough bytes for
620 thisrr->length -= mac_size;
621 mac = &thisrr->data[thisrr->length];
624 i = s->method->ssl3_enc->mac(s, thisrr, md, 0 /* not send */ );
625 if (i == 0 || mac == NULL
626 || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0)
628 if (thisrr->length > SSL3_RT_MAX_COMPRESSED_LENGTH + mac_size)
634 if (ossl_statem_in_error(s)) {
635 /* We already called SSLfatal() */
638 if (num_recs == 1 && ossl_statem_skip_early_data(s)) {
640 * We assume this is unreadable early_data - we treat it like an
645 * The record length may have been modified by the mac check above
646 * so we use the previously saved value
648 if (!early_data_count_ok(s, first_rec_len,
649 EARLY_DATA_CIPHERTEXT_OVERHEAD, 0)) {
650 /* SSLfatal() already called */
657 RECORD_LAYER_set_numrpipes(&s->rlayer, 1);
658 RECORD_LAYER_reset_read_sequence(&s->rlayer);
662 * A separate 'decryption_failed' alert was introduced with TLS 1.0,
663 * SSL 3.0 only has 'bad_record_mac'. But unless a decryption
664 * failure is directly visible from the ciphertext anyway, we should
665 * not reveal which kind of error occurred -- this might become
666 * visible to an attacker (e.g. via a logfile)
668 SSLfatal(s, SSL_AD_BAD_RECORD_MAC, SSL_F_SSL3_GET_RECORD,
669 SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
673 for (j = 0; j < num_recs; j++) {
676 /* thisrr->length is now just compressed */
677 if (s->expand != NULL) {
678 if (thisrr->length > SSL3_RT_MAX_COMPRESSED_LENGTH) {
679 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD,
680 SSL_R_COMPRESSED_LENGTH_TOO_LONG);
683 if (!ssl3_do_uncompress(s, thisrr)) {
684 SSLfatal(s, SSL_AD_DECOMPRESSION_FAILURE, SSL_F_SSL3_GET_RECORD,
685 SSL_R_BAD_DECOMPRESSION);
690 if (SSL_IS_TLS13(s) && s->enc_read_ctx != NULL) {
693 if (thisrr->length == 0
694 || thisrr->type != SSL3_RT_APPLICATION_DATA) {
695 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_F_SSL3_GET_RECORD,
696 SSL_R_BAD_RECORD_TYPE);
700 /* Strip trailing padding */
701 for (end = thisrr->length - 1; end > 0 && thisrr->data[end] == 0;
705 thisrr->length = end;
706 thisrr->type = thisrr->data[end];
707 if (thisrr->type != SSL3_RT_APPLICATION_DATA
708 && thisrr->type != SSL3_RT_ALERT
709 && thisrr->type != SSL3_RT_HANDSHAKE) {
710 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_F_SSL3_GET_RECORD,
711 SSL_R_BAD_RECORD_TYPE);
715 s->msg_callback(0, s->version, SSL3_RT_INNER_CONTENT_TYPE,
716 &thisrr->data[end], 1, s, s->msg_callback_arg);
720 * TLSv1.3 alert and handshake records are required to be non-zero in
724 && (thisrr->type == SSL3_RT_HANDSHAKE
725 || thisrr->type == SSL3_RT_ALERT)
726 && thisrr->length == 0) {
727 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_F_SSL3_GET_RECORD,
732 if (thisrr->length > SSL3_RT_MAX_PLAIN_LENGTH) {
733 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD,
734 SSL_R_DATA_LENGTH_TOO_LONG);
738 /* If received packet overflows current Max Fragment Length setting */
739 if (s->session != NULL && USE_MAX_FRAGMENT_LENGTH_EXT(s->session)
740 && thisrr->length > GET_MAX_FRAGMENT_LENGTH(s->session)) {
741 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD,
742 SSL_R_DATA_LENGTH_TOO_LONG);
748 * So at this point the following is true
749 * thisrr->type is the type of record
750 * thisrr->length == number of bytes in record
751 * thisrr->off == offset to first valid byte
752 * thisrr->data == where to take bytes from, increment after use :-).
755 /* just read a 0 length packet */
756 if (thisrr->length == 0) {
757 RECORD_LAYER_inc_empty_record_count(&s->rlayer);
758 if (RECORD_LAYER_get_empty_record_count(&s->rlayer)
759 > MAX_EMPTY_RECORDS) {
760 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_F_SSL3_GET_RECORD,
761 SSL_R_RECORD_TOO_SMALL);
765 RECORD_LAYER_reset_empty_record_count(&s->rlayer);
769 if (s->early_data_state == SSL_EARLY_DATA_READING) {
771 if (thisrr->type == SSL3_RT_APPLICATION_DATA
772 && !early_data_count_ok(s, thisrr->length, 0, 0)) {
773 /* SSLfatal already called */
778 RECORD_LAYER_set_numrpipes(&s->rlayer, num_recs);
782 int ssl3_do_uncompress(SSL *ssl, SSL3_RECORD *rr)
784 #ifndef OPENSSL_NO_COMP
787 if (rr->comp == NULL) {
788 rr->comp = (unsigned char *)
789 OPENSSL_malloc(SSL3_RT_MAX_ENCRYPTED_LENGTH);
791 if (rr->comp == NULL)
794 /* TODO(size_t): Convert this call */
795 i = COMP_expand_block(ssl->expand, rr->comp,
796 SSL3_RT_MAX_PLAIN_LENGTH, rr->data, (int)rr->length);
806 int ssl3_do_compress(SSL *ssl, SSL3_RECORD *wr)
808 #ifndef OPENSSL_NO_COMP
811 /* TODO(size_t): Convert this call */
812 i = COMP_compress_block(ssl->compress, wr->data,
813 (int)(wr->length + SSL3_RT_MAX_COMPRESSED_OVERHEAD),
814 wr->input, (int)wr->length);
820 wr->input = wr->data;
826 * ssl3_enc encrypts/decrypts |n_recs| records in |inrecs|. Will call
827 * SSLfatal() for internal errors, but not otherwise.
830 * 0: (in non-constant time) if the record is publically invalid (i.e. too
832 * 1: if the record's padding is valid / the encryption was successful.
833 * -1: if the record's padding is invalid or, if sending, an internal error
836 int ssl3_enc(SSL *s, SSL3_RECORD *inrecs, size_t n_recs, int sending)
841 size_t bs, mac_size = 0;
843 const EVP_CIPHER *enc;
847 * We shouldn't ever be called with more than one record in the SSLv3 case
852 ds = s->enc_write_ctx;
853 if (s->enc_write_ctx == NULL)
856 enc = EVP_CIPHER_CTX_cipher(s->enc_write_ctx);
858 ds = s->enc_read_ctx;
859 if (s->enc_read_ctx == NULL)
862 enc = EVP_CIPHER_CTX_cipher(s->enc_read_ctx);
865 if ((s->session == NULL) || (ds == NULL) || (enc == NULL)) {
866 memmove(rec->data, rec->input, rec->length);
867 rec->input = rec->data;
870 /* TODO(size_t): Convert this call */
871 bs = EVP_CIPHER_CTX_block_size(ds);
875 if ((bs != 1) && sending) {
878 /* we need to add 'i-1' padding bytes */
881 * the last of these zero bytes will be overwritten with the
884 memset(&rec->input[rec->length], 0, i);
886 rec->input[l - 1] = (unsigned char)(i - 1);
890 if (l == 0 || l % bs != 0)
892 /* otherwise, rec->length >= bs */
895 /* TODO(size_t): Convert this call */
896 if (EVP_Cipher(ds, rec->data, rec->input, (unsigned int)l) < 1)
899 if (EVP_MD_CTX_md(s->read_hash) != NULL) {
900 /* TODO(size_t): convert me */
901 imac_size = EVP_MD_CTX_size(s->read_hash);
903 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_SSL3_ENC,
904 ERR_R_INTERNAL_ERROR);
907 mac_size = (size_t)imac_size;
909 if ((bs != 1) && !sending)
910 return ssl3_cbc_remove_padding(rec, bs, mac_size);
915 #define MAX_PADDING 256
917 * tls1_enc encrypts/decrypts |n_recs| in |recs|. Will call SSLfatal() for
918 * internal errors, but not otherwise.
921 * 0: (in non-constant time) if the record is publically invalid (i.e. too
923 * 1: if the record's padding is valid / the encryption was successful.
924 * -1: if the record's padding/AEAD-authenticator is invalid or, if sending,
925 * an internal error occurred.
927 int tls1_enc(SSL *s, SSL3_RECORD *recs, size_t n_recs, int sending)
930 size_t reclen[SSL_MAX_PIPELINES];
931 unsigned char buf[SSL_MAX_PIPELINES][EVP_AEAD_TLS1_AAD_LEN];
932 int i, pad = 0, ret, tmpr;
933 size_t bs, mac_size = 0, ctr, padnum, loop;
934 unsigned char padval;
936 const EVP_CIPHER *enc;
939 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
940 ERR_R_INTERNAL_ERROR);
945 if (EVP_MD_CTX_md(s->write_hash)) {
946 int n = EVP_MD_CTX_size(s->write_hash);
947 if (!ossl_assert(n >= 0)) {
948 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
949 ERR_R_INTERNAL_ERROR);
953 ds = s->enc_write_ctx;
954 if (s->enc_write_ctx == NULL)
958 enc = EVP_CIPHER_CTX_cipher(s->enc_write_ctx);
959 /* For TLSv1.1 and later explicit IV */
960 if (SSL_USE_EXPLICIT_IV(s)
961 && EVP_CIPHER_mode(enc) == EVP_CIPH_CBC_MODE)
962 ivlen = EVP_CIPHER_iv_length(enc);
966 for (ctr = 0; ctr < n_recs; ctr++) {
967 if (recs[ctr].data != recs[ctr].input) {
969 * we can't write into the input stream: Can this ever
972 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
973 ERR_R_INTERNAL_ERROR);
975 } else if (ssl_randbytes(s, recs[ctr].input, ivlen) <= 0) {
976 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
977 ERR_R_INTERNAL_ERROR);
984 if (EVP_MD_CTX_md(s->read_hash)) {
985 int n = EVP_MD_CTX_size(s->read_hash);
986 if (!ossl_assert(n >= 0)) {
987 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
988 ERR_R_INTERNAL_ERROR);
992 ds = s->enc_read_ctx;
993 if (s->enc_read_ctx == NULL)
996 enc = EVP_CIPHER_CTX_cipher(s->enc_read_ctx);
999 if ((s->session == NULL) || (ds == NULL) || (enc == NULL)) {
1000 for (ctr = 0; ctr < n_recs; ctr++) {
1001 memmove(recs[ctr].data, recs[ctr].input, recs[ctr].length);
1002 recs[ctr].input = recs[ctr].data;
1006 bs = EVP_CIPHER_block_size(EVP_CIPHER_CTX_cipher(ds));
1009 if (!(EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(ds))
1010 & EVP_CIPH_FLAG_PIPELINE)) {
1012 * We shouldn't have been called with pipeline data if the
1013 * cipher doesn't support pipelining
1015 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
1016 SSL_R_PIPELINE_FAILURE);
1020 for (ctr = 0; ctr < n_recs; ctr++) {
1021 reclen[ctr] = recs[ctr].length;
1023 if (EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(ds))
1024 & EVP_CIPH_FLAG_AEAD_CIPHER) {
1027 seq = sending ? RECORD_LAYER_get_write_sequence(&s->rlayer)
1028 : RECORD_LAYER_get_read_sequence(&s->rlayer);
1030 if (SSL_IS_DTLS(s)) {
1031 /* DTLS does not support pipelining */
1032 unsigned char dtlsseq[9], *p = dtlsseq;
1034 s2n(sending ? DTLS_RECORD_LAYER_get_w_epoch(&s->rlayer) :
1035 DTLS_RECORD_LAYER_get_r_epoch(&s->rlayer), p);
1036 memcpy(p, &seq[2], 6);
1037 memcpy(buf[ctr], dtlsseq, 8);
1039 memcpy(buf[ctr], seq, 8);
1040 for (i = 7; i >= 0; i--) { /* increment */
1047 buf[ctr][8] = recs[ctr].type;
1048 buf[ctr][9] = (unsigned char)(s->version >> 8);
1049 buf[ctr][10] = (unsigned char)(s->version);
1050 buf[ctr][11] = (unsigned char)(recs[ctr].length >> 8);
1051 buf[ctr][12] = (unsigned char)(recs[ctr].length & 0xff);
1052 pad = EVP_CIPHER_CTX_ctrl(ds, EVP_CTRL_AEAD_TLS1_AAD,
1053 EVP_AEAD_TLS1_AAD_LEN, buf[ctr]);
1055 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
1056 ERR_R_INTERNAL_ERROR);
1062 recs[ctr].length += pad;
1065 } else if ((bs != 1) && sending) {
1066 padnum = bs - (reclen[ctr] % bs);
1068 /* Add weird padding of upto 256 bytes */
1070 if (padnum > MAX_PADDING) {
1071 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
1072 ERR_R_INTERNAL_ERROR);
1075 /* we need to add 'padnum' padding bytes of value padval */
1076 padval = (unsigned char)(padnum - 1);
1077 for (loop = reclen[ctr]; loop < reclen[ctr] + padnum; loop++)
1078 recs[ctr].input[loop] = padval;
1079 reclen[ctr] += padnum;
1080 recs[ctr].length += padnum;
1084 if (reclen[ctr] == 0 || reclen[ctr] % bs != 0)
1089 unsigned char *data[SSL_MAX_PIPELINES];
1091 /* Set the output buffers */
1092 for (ctr = 0; ctr < n_recs; ctr++) {
1093 data[ctr] = recs[ctr].data;
1095 if (EVP_CIPHER_CTX_ctrl(ds, EVP_CTRL_SET_PIPELINE_OUTPUT_BUFS,
1096 (int)n_recs, data) <= 0) {
1097 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
1098 SSL_R_PIPELINE_FAILURE);
1101 /* Set the input buffers */
1102 for (ctr = 0; ctr < n_recs; ctr++) {
1103 data[ctr] = recs[ctr].input;
1105 if (EVP_CIPHER_CTX_ctrl(ds, EVP_CTRL_SET_PIPELINE_INPUT_BUFS,
1106 (int)n_recs, data) <= 0
1107 || EVP_CIPHER_CTX_ctrl(ds, EVP_CTRL_SET_PIPELINE_INPUT_LENS,
1108 (int)n_recs, reclen) <= 0) {
1109 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
1110 SSL_R_PIPELINE_FAILURE);
1115 /* TODO(size_t): Convert this call */
1116 tmpr = EVP_Cipher(ds, recs[0].data, recs[0].input,
1117 (unsigned int)reclen[0]);
1118 if ((EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(ds))
1119 & EVP_CIPH_FLAG_CUSTOM_CIPHER)
1122 return -1; /* AEAD can fail to verify MAC */
1125 if (EVP_CIPHER_mode(enc) == EVP_CIPH_GCM_MODE) {
1126 for (ctr = 0; ctr < n_recs; ctr++) {
1127 recs[ctr].data += EVP_GCM_TLS_EXPLICIT_IV_LEN;
1128 recs[ctr].input += EVP_GCM_TLS_EXPLICIT_IV_LEN;
1129 recs[ctr].length -= EVP_GCM_TLS_EXPLICIT_IV_LEN;
1131 } else if (EVP_CIPHER_mode(enc) == EVP_CIPH_CCM_MODE) {
1132 for (ctr = 0; ctr < n_recs; ctr++) {
1133 recs[ctr].data += EVP_CCM_TLS_EXPLICIT_IV_LEN;
1134 recs[ctr].input += EVP_CCM_TLS_EXPLICIT_IV_LEN;
1135 recs[ctr].length -= EVP_CCM_TLS_EXPLICIT_IV_LEN;
1141 if (!SSL_READ_ETM(s) && EVP_MD_CTX_md(s->read_hash) != NULL) {
1142 imac_size = EVP_MD_CTX_size(s->read_hash);
1143 if (imac_size < 0) {
1144 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
1145 ERR_R_INTERNAL_ERROR);
1148 mac_size = (size_t)imac_size;
1150 if ((bs != 1) && !sending) {
1152 for (ctr = 0; ctr < n_recs; ctr++) {
1153 tmpret = tls1_cbc_remove_padding(s, &recs[ctr], bs, mac_size);
1155 * If tmpret == 0 then this means publicly invalid so we can
1156 * short circuit things here. Otherwise we must respect constant
1161 ret = constant_time_select_int(constant_time_eq_int(tmpret, 1),
1165 if (pad && !sending) {
1166 for (ctr = 0; ctr < n_recs; ctr++) {
1167 recs[ctr].length -= pad;
1174 int n_ssl3_mac(SSL *ssl, SSL3_RECORD *rec, unsigned char *md, int sending)
1176 unsigned char *mac_sec, *seq;
1177 const EVP_MD_CTX *hash;
1178 unsigned char *p, rec_char;
1184 mac_sec = &(ssl->s3->write_mac_secret[0]);
1185 seq = RECORD_LAYER_get_write_sequence(&ssl->rlayer);
1186 hash = ssl->write_hash;
1188 mac_sec = &(ssl->s3->read_mac_secret[0]);
1189 seq = RECORD_LAYER_get_read_sequence(&ssl->rlayer);
1190 hash = ssl->read_hash;
1193 t = EVP_MD_CTX_size(hash);
1197 npad = (48 / md_size) * md_size;
1200 EVP_CIPHER_CTX_mode(ssl->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
1201 ssl3_cbc_record_digest_supported(hash)) {
1203 * This is a CBC-encrypted record. We must avoid leaking any
1204 * timing-side channel information about how many blocks of data we
1205 * are hashing because that gives an attacker a timing-oracle.
1209 * npad is, at most, 48 bytes and that's with MD5:
1210 * 16 + 48 + 8 (sequence bytes) + 1 + 2 = 75.
1212 * With SHA-1 (the largest hash speced for SSLv3) the hash size
1213 * goes up 4, but npad goes down by 8, resulting in a smaller
1216 unsigned char header[75];
1218 memcpy(header + j, mac_sec, md_size);
1220 memcpy(header + j, ssl3_pad_1, npad);
1222 memcpy(header + j, seq, 8);
1224 header[j++] = rec->type;
1225 header[j++] = (unsigned char)(rec->length >> 8);
1226 header[j++] = (unsigned char)(rec->length & 0xff);
1228 /* Final param == is SSLv3 */
1229 if (ssl3_cbc_digest_record(hash,
1232 rec->length + md_size, rec->orig_len,
1233 mac_sec, md_size, 1) <= 0)
1236 unsigned int md_size_u;
1237 /* Chop the digest off the end :-) */
1238 EVP_MD_CTX *md_ctx = EVP_MD_CTX_new();
1243 rec_char = rec->type;
1245 s2n(rec->length, p);
1246 if (EVP_MD_CTX_copy_ex(md_ctx, hash) <= 0
1247 || EVP_DigestUpdate(md_ctx, mac_sec, md_size) <= 0
1248 || EVP_DigestUpdate(md_ctx, ssl3_pad_1, npad) <= 0
1249 || EVP_DigestUpdate(md_ctx, seq, 8) <= 0
1250 || EVP_DigestUpdate(md_ctx, &rec_char, 1) <= 0
1251 || EVP_DigestUpdate(md_ctx, md, 2) <= 0
1252 || EVP_DigestUpdate(md_ctx, rec->input, rec->length) <= 0
1253 || EVP_DigestFinal_ex(md_ctx, md, NULL) <= 0
1254 || EVP_MD_CTX_copy_ex(md_ctx, hash) <= 0
1255 || EVP_DigestUpdate(md_ctx, mac_sec, md_size) <= 0
1256 || EVP_DigestUpdate(md_ctx, ssl3_pad_2, npad) <= 0
1257 || EVP_DigestUpdate(md_ctx, md, md_size) <= 0
1258 || EVP_DigestFinal_ex(md_ctx, md, &md_size_u) <= 0) {
1259 EVP_MD_CTX_reset(md_ctx);
1263 EVP_MD_CTX_free(md_ctx);
1266 ssl3_record_sequence_update(seq);
1270 int tls1_mac(SSL *ssl, SSL3_RECORD *rec, unsigned char *md, int sending)
1276 EVP_MD_CTX *hmac = NULL, *mac_ctx;
1277 unsigned char header[13];
1278 int stream_mac = (sending ? (ssl->mac_flags & SSL_MAC_FLAG_WRITE_MAC_STREAM)
1279 : (ssl->mac_flags & SSL_MAC_FLAG_READ_MAC_STREAM));
1283 seq = RECORD_LAYER_get_write_sequence(&ssl->rlayer);
1284 hash = ssl->write_hash;
1286 seq = RECORD_LAYER_get_read_sequence(&ssl->rlayer);
1287 hash = ssl->read_hash;
1290 t = EVP_MD_CTX_size(hash);
1291 if (!ossl_assert(t >= 0))
1295 /* I should fix this up TLS TLS TLS TLS TLS XXXXXXXX */
1299 hmac = EVP_MD_CTX_new();
1300 if (hmac == NULL || !EVP_MD_CTX_copy(hmac, hash))
1305 if (SSL_IS_DTLS(ssl)) {
1306 unsigned char dtlsseq[8], *p = dtlsseq;
1308 s2n(sending ? DTLS_RECORD_LAYER_get_w_epoch(&ssl->rlayer) :
1309 DTLS_RECORD_LAYER_get_r_epoch(&ssl->rlayer), p);
1310 memcpy(p, &seq[2], 6);
1312 memcpy(header, dtlsseq, 8);
1314 memcpy(header, seq, 8);
1316 header[8] = rec->type;
1317 header[9] = (unsigned char)(ssl->version >> 8);
1318 header[10] = (unsigned char)(ssl->version);
1319 header[11] = (unsigned char)(rec->length >> 8);
1320 header[12] = (unsigned char)(rec->length & 0xff);
1322 if (!sending && !SSL_READ_ETM(ssl) &&
1323 EVP_CIPHER_CTX_mode(ssl->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
1324 ssl3_cbc_record_digest_supported(mac_ctx)) {
1326 * This is a CBC-encrypted record. We must avoid leaking any
1327 * timing-side channel information about how many blocks of data we
1328 * are hashing because that gives an attacker a timing-oracle.
1330 /* Final param == not SSLv3 */
1331 if (ssl3_cbc_digest_record(mac_ctx,
1334 rec->length + md_size, rec->orig_len,
1335 ssl->s3->read_mac_secret,
1336 ssl->s3->read_mac_secret_size, 0) <= 0) {
1337 EVP_MD_CTX_free(hmac);
1341 /* TODO(size_t): Convert these calls */
1342 if (EVP_DigestSignUpdate(mac_ctx, header, sizeof(header)) <= 0
1343 || EVP_DigestSignUpdate(mac_ctx, rec->input, rec->length) <= 0
1344 || EVP_DigestSignFinal(mac_ctx, md, &md_size) <= 0) {
1345 EVP_MD_CTX_free(hmac);
1350 EVP_MD_CTX_free(hmac);
1353 fprintf(stderr, "seq=");
1356 for (z = 0; z < 8; z++)
1357 fprintf(stderr, "%02X ", seq[z]);
1358 fprintf(stderr, "\n");
1360 fprintf(stderr, "rec=");
1363 for (z = 0; z < rec->length; z++)
1364 fprintf(stderr, "%02X ", rec->data[z]);
1365 fprintf(stderr, "\n");
1369 if (!SSL_IS_DTLS(ssl)) {
1370 for (i = 7; i >= 0; i--) {
1379 for (z = 0; z < md_size; z++)
1380 fprintf(stderr, "%02X ", md[z]);
1381 fprintf(stderr, "\n");
1388 * ssl3_cbc_remove_padding removes padding from the decrypted, SSLv3, CBC
1389 * record in |rec| by updating |rec->length| in constant time.
1391 * block_size: the block size of the cipher used to encrypt the record.
1393 * 0: (in non-constant time) if the record is publicly invalid.
1394 * 1: if the padding was valid
1397 int ssl3_cbc_remove_padding(SSL3_RECORD *rec,
1398 size_t block_size, size_t mac_size)
1400 size_t padding_length;
1402 const size_t overhead = 1 /* padding length byte */ + mac_size;
1405 * These lengths are all public so we can test them in non-constant time.
1407 if (overhead > rec->length)
1410 padding_length = rec->data[rec->length - 1];
1411 good = constant_time_ge_s(rec->length, padding_length + overhead);
1412 /* SSLv3 requires that the padding is minimal. */
1413 good &= constant_time_ge_s(block_size, padding_length + 1);
1414 rec->length -= good & (padding_length + 1);
1415 return constant_time_select_int_s(good, 1, -1);
1419 * tls1_cbc_remove_padding removes the CBC padding from the decrypted, TLS, CBC
1420 * record in |rec| in constant time and returns 1 if the padding is valid and
1421 * -1 otherwise. It also removes any explicit IV from the start of the record
1422 * without leaking any timing about whether there was enough space after the
1423 * padding was removed.
1425 * block_size: the block size of the cipher used to encrypt the record.
1427 * 0: (in non-constant time) if the record is publicly invalid.
1428 * 1: if the padding was valid
1431 int tls1_cbc_remove_padding(const SSL *s,
1433 size_t block_size, size_t mac_size)
1436 size_t padding_length, to_check, i;
1437 const size_t overhead = 1 /* padding length byte */ + mac_size;
1438 /* Check if version requires explicit IV */
1439 if (SSL_USE_EXPLICIT_IV(s)) {
1441 * These lengths are all public so we can test them in non-constant
1444 if (overhead + block_size > rec->length)
1446 /* We can now safely skip explicit IV */
1447 rec->data += block_size;
1448 rec->input += block_size;
1449 rec->length -= block_size;
1450 rec->orig_len -= block_size;
1451 } else if (overhead > rec->length)
1454 padding_length = rec->data[rec->length - 1];
1456 if (EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(s->enc_read_ctx)) &
1457 EVP_CIPH_FLAG_AEAD_CIPHER) {
1458 /* padding is already verified */
1459 rec->length -= padding_length + 1;
1463 good = constant_time_ge_s(rec->length, overhead + padding_length);
1465 * The padding consists of a length byte at the end of the record and
1466 * then that many bytes of padding, all with the same value as the length
1467 * byte. Thus, with the length byte included, there are i+1 bytes of
1468 * padding. We can't check just |padding_length+1| bytes because that
1469 * leaks decrypted information. Therefore we always have to check the
1470 * maximum amount of padding possible. (Again, the length of the record
1471 * is public information so we can use it.)
1473 to_check = 256; /* maximum amount of padding, inc length byte. */
1474 if (to_check > rec->length)
1475 to_check = rec->length;
1477 for (i = 0; i < to_check; i++) {
1478 unsigned char mask = constant_time_ge_8_s(padding_length, i);
1479 unsigned char b = rec->data[rec->length - 1 - i];
1481 * The final |padding_length+1| bytes should all have the value
1482 * |padding_length|. Therefore the XOR should be zero.
1484 good &= ~(mask & (padding_length ^ b));
1488 * If any of the final |padding_length+1| bytes had the wrong value, one
1489 * or more of the lower eight bits of |good| will be cleared.
1491 good = constant_time_eq_s(0xff, good & 0xff);
1492 rec->length -= good & (padding_length + 1);
1494 return constant_time_select_int_s(good, 1, -1);
1498 * ssl3_cbc_copy_mac copies |md_size| bytes from the end of |rec| to |out| in
1499 * constant time (independent of the concrete value of rec->length, which may
1500 * vary within a 256-byte window).
1502 * ssl3_cbc_remove_padding or tls1_cbc_remove_padding must be called prior to
1506 * rec->orig_len >= md_size
1507 * md_size <= EVP_MAX_MD_SIZE
1509 * If CBC_MAC_ROTATE_IN_PLACE is defined then the rotation is performed with
1510 * variable accesses in a 64-byte-aligned buffer. Assuming that this fits into
1511 * a single or pair of cache-lines, then the variable memory accesses don't
1512 * actually affect the timing. CPUs with smaller cache-lines [if any] are
1513 * not multi-core and are not considered vulnerable to cache-timing attacks.
1515 #define CBC_MAC_ROTATE_IN_PLACE
1517 int ssl3_cbc_copy_mac(unsigned char *out,
1518 const SSL3_RECORD *rec, size_t md_size)
1520 #if defined(CBC_MAC_ROTATE_IN_PLACE)
1521 unsigned char rotated_mac_buf[64 + EVP_MAX_MD_SIZE];
1522 unsigned char *rotated_mac;
1524 unsigned char rotated_mac[EVP_MAX_MD_SIZE];
1528 * mac_end is the index of |rec->data| just after the end of the MAC.
1530 size_t mac_end = rec->length;
1531 size_t mac_start = mac_end - md_size;
1534 * scan_start contains the number of bytes that we can ignore because the
1535 * MAC's position can only vary by 255 bytes.
1537 size_t scan_start = 0;
1539 size_t rotate_offset;
1541 if (!ossl_assert(rec->orig_len >= md_size
1542 && md_size <= EVP_MAX_MD_SIZE))
1545 #if defined(CBC_MAC_ROTATE_IN_PLACE)
1546 rotated_mac = rotated_mac_buf + ((0 - (size_t)rotated_mac_buf) & 63);
1549 /* This information is public so it's safe to branch based on it. */
1550 if (rec->orig_len > md_size + 255 + 1)
1551 scan_start = rec->orig_len - (md_size + 255 + 1);
1555 memset(rotated_mac, 0, md_size);
1556 for (i = scan_start, j = 0; i < rec->orig_len; i++) {
1557 size_t mac_started = constant_time_eq_s(i, mac_start);
1558 size_t mac_ended = constant_time_lt_s(i, mac_end);
1559 unsigned char b = rec->data[i];
1561 in_mac |= mac_started;
1562 in_mac &= mac_ended;
1563 rotate_offset |= j & mac_started;
1564 rotated_mac[j++] |= b & in_mac;
1565 j &= constant_time_lt_s(j, md_size);
1568 /* Now rotate the MAC */
1569 #if defined(CBC_MAC_ROTATE_IN_PLACE)
1571 for (i = 0; i < md_size; i++) {
1572 /* in case cache-line is 32 bytes, touch second line */
1573 ((volatile unsigned char *)rotated_mac)[rotate_offset ^ 32];
1574 out[j++] = rotated_mac[rotate_offset++];
1575 rotate_offset &= constant_time_lt_s(rotate_offset, md_size);
1578 memset(out, 0, md_size);
1579 rotate_offset = md_size - rotate_offset;
1580 rotate_offset &= constant_time_lt_s(rotate_offset, md_size);
1581 for (i = 0; i < md_size; i++) {
1582 for (j = 0; j < md_size; j++)
1583 out[j] |= rotated_mac[i] & constant_time_eq_8_s(j, rotate_offset);
1585 rotate_offset &= constant_time_lt_s(rotate_offset, md_size);
1592 int dtls1_process_record(SSL *s, DTLS1_BITMAP *bitmap)
1600 unsigned char md[EVP_MAX_MD_SIZE];
1602 rr = RECORD_LAYER_get_rrec(&s->rlayer);
1606 * At this point, s->packet_length == SSL3_RT_HEADER_LNGTH + rr->length,
1607 * and we have that many bytes in s->packet
1609 rr->input = &(RECORD_LAYER_get_packet(&s->rlayer)[DTLS1_RT_HEADER_LENGTH]);
1612 * ok, we can now read from 's->packet' data into 'rr' rr->input points
1613 * at rr->length bytes, which need to be copied into rr->data by either
1614 * the decryption or by the decompression When the data is 'copied' into
1615 * the rr->data buffer, rr->input will be pointed at the new buffer
1619 * We now have - encrypted [ MAC [ compressed [ plain ] ] ] rr->length
1620 * bytes of encrypted compressed stuff.
1623 /* check is not needed I believe */
1624 if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH) {
1625 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_DTLS1_PROCESS_RECORD,
1626 SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
1630 /* decrypt in place in 'rr->input' */
1631 rr->data = rr->input;
1632 rr->orig_len = rr->length;
1634 if (SSL_READ_ETM(s) && s->read_hash) {
1636 mac_size = EVP_MD_CTX_size(s->read_hash);
1637 if (!ossl_assert(mac_size <= EVP_MAX_MD_SIZE)) {
1638 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DTLS1_PROCESS_RECORD,
1639 ERR_R_INTERNAL_ERROR);
1642 if (rr->orig_len < mac_size) {
1643 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_DTLS1_PROCESS_RECORD,
1644 SSL_R_LENGTH_TOO_SHORT);
1647 rr->length -= mac_size;
1648 mac = rr->data + rr->length;
1649 i = s->method->ssl3_enc->mac(s, rr, md, 0 /* not send */ );
1650 if (i == 0 || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0) {
1651 SSLfatal(s, SSL_AD_BAD_RECORD_MAC, SSL_F_DTLS1_PROCESS_RECORD,
1652 SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
1657 enc_err = s->method->ssl3_enc->enc(s, rr, 1, 0);
1660 * 0: (in non-constant time) if the record is publically invalid.
1661 * 1: if the padding is valid
1662 * -1: if the padding is invalid
1665 if (ossl_statem_in_error(s)) {
1666 /* SSLfatal() got called */
1669 /* For DTLS we simply ignore bad packets. */
1671 RECORD_LAYER_reset_packet_length(&s->rlayer);
1675 printf("dec %ld\n", rr->length);
1678 for (z = 0; z < rr->length; z++)
1679 printf("%02X%c", rr->data[z], ((z + 1) % 16) ? ' ' : '\n');
1684 /* r->length is now the compressed data plus mac */
1685 if ((sess != NULL) && !SSL_READ_ETM(s) &&
1686 (s->enc_read_ctx != NULL) && (EVP_MD_CTX_md(s->read_hash) != NULL)) {
1687 /* s->read_hash != NULL => mac_size != -1 */
1688 unsigned char *mac = NULL;
1689 unsigned char mac_tmp[EVP_MAX_MD_SIZE];
1691 /* TODO(size_t): Convert this to do size_t properly */
1692 imac_size = EVP_MD_CTX_size(s->read_hash);
1693 if (imac_size < 0) {
1694 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DTLS1_PROCESS_RECORD,
1698 mac_size = (size_t)imac_size;
1699 if (!ossl_assert(mac_size <= EVP_MAX_MD_SIZE)) {
1700 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DTLS1_PROCESS_RECORD,
1701 ERR_R_INTERNAL_ERROR);
1706 * orig_len is the length of the record before any padding was
1707 * removed. This is public information, as is the MAC in use,
1708 * therefore we can safely process the record in a different amount
1709 * of time if it's too short to possibly contain a MAC.
1711 if (rr->orig_len < mac_size ||
1712 /* CBC records must have a padding length byte too. */
1713 (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
1714 rr->orig_len < mac_size + 1)) {
1715 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_DTLS1_PROCESS_RECORD,
1716 SSL_R_LENGTH_TOO_SHORT);
1720 if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE) {
1722 * We update the length so that the TLS header bytes can be
1723 * constructed correctly but we need to extract the MAC in
1724 * constant time from within the record, without leaking the
1725 * contents of the padding bytes.
1728 if (!ssl3_cbc_copy_mac(mac_tmp, rr, mac_size)) {
1729 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DTLS1_PROCESS_RECORD,
1730 ERR_R_INTERNAL_ERROR);
1733 rr->length -= mac_size;
1736 * In this case there's no padding, so |rec->orig_len| equals
1737 * |rec->length| and we checked that there's enough bytes for
1740 rr->length -= mac_size;
1741 mac = &rr->data[rr->length];
1744 i = s->method->ssl3_enc->mac(s, rr, md, 0 /* not send */ );
1745 if (i == 0 || mac == NULL
1746 || CRYPTO_memcmp(md, mac, mac_size) != 0)
1748 if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH + mac_size)
1753 /* decryption failed, silently discard message */
1755 RECORD_LAYER_reset_packet_length(&s->rlayer);
1759 /* r->length is now just compressed */
1760 if (s->expand != NULL) {
1761 if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH) {
1762 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_DTLS1_PROCESS_RECORD,
1763 SSL_R_COMPRESSED_LENGTH_TOO_LONG);
1766 if (!ssl3_do_uncompress(s, rr)) {
1767 SSLfatal(s, SSL_AD_DECOMPRESSION_FAILURE,
1768 SSL_F_DTLS1_PROCESS_RECORD, SSL_R_BAD_DECOMPRESSION);
1773 if (rr->length > SSL3_RT_MAX_PLAIN_LENGTH) {
1774 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_DTLS1_PROCESS_RECORD,
1775 SSL_R_DATA_LENGTH_TOO_LONG);
1781 * So at this point the following is true
1782 * ssl->s3->rrec.type is the type of record
1783 * ssl->s3->rrec.length == number of bytes in record
1784 * ssl->s3->rrec.off == offset to first valid byte
1785 * ssl->s3->rrec.data == where to take bytes from, increment
1789 /* we have pulled in a full packet so zero things */
1790 RECORD_LAYER_reset_packet_length(&s->rlayer);
1792 /* Mark receipt of record. */
1793 dtls1_record_bitmap_update(s, bitmap);
1799 * Retrieve a buffered record that belongs to the current epoch, i.e. processed
1801 #define dtls1_get_processed_record(s) \
1802 dtls1_retrieve_buffered_record((s), \
1803 &(DTLS_RECORD_LAYER_get_processed_rcds(&s->rlayer)))
1806 * Call this to get a new input record.
1807 * It will return <= 0 if more data is needed, normally due to an error
1808 * or non-blocking IO.
1809 * When it finishes, one packet has been decoded and can be found in
1810 * ssl->s3->rrec.type - is the type of record
1811 * ssl->s3->rrec.data, - data
1812 * ssl->s3->rrec.length, - number of bytes
1814 /* used only by dtls1_read_bytes */
1815 int dtls1_get_record(SSL *s)
1817 int ssl_major, ssl_minor;
1821 unsigned char *p = NULL;
1822 unsigned short version;
1823 DTLS1_BITMAP *bitmap;
1824 unsigned int is_next_epoch;
1826 rr = RECORD_LAYER_get_rrec(&s->rlayer);
1830 * The epoch may have changed. If so, process all the pending records.
1831 * This is a non-blocking operation.
1833 if (!dtls1_process_buffered_records(s)) {
1834 /* SSLfatal() already called */
1838 /* if we're renegotiating, then there may be buffered records */
1839 if (dtls1_get_processed_record(s))
1842 /* get something from the wire */
1844 /* check if we have the header */
1845 if ((RECORD_LAYER_get_rstate(&s->rlayer) != SSL_ST_READ_BODY) ||
1846 (RECORD_LAYER_get_packet_length(&s->rlayer) < DTLS1_RT_HEADER_LENGTH)) {
1847 rret = ssl3_read_n(s, DTLS1_RT_HEADER_LENGTH,
1848 SSL3_BUFFER_get_len(&s->rlayer.rbuf), 0, 1, &n);
1849 /* read timeout is handled by dtls1_read_bytes */
1851 /* SSLfatal() already called if appropriate */
1852 return rret; /* error or non-blocking */
1855 /* this packet contained a partial record, dump it */
1856 if (RECORD_LAYER_get_packet_length(&s->rlayer) !=
1857 DTLS1_RT_HEADER_LENGTH) {
1858 RECORD_LAYER_reset_packet_length(&s->rlayer);
1862 RECORD_LAYER_set_rstate(&s->rlayer, SSL_ST_READ_BODY);
1864 p = RECORD_LAYER_get_packet(&s->rlayer);
1866 if (s->msg_callback)
1867 s->msg_callback(0, 0, SSL3_RT_HEADER, p, DTLS1_RT_HEADER_LENGTH,
1868 s, s->msg_callback_arg);
1870 /* Pull apart the header into the DTLS1_RECORD */
1874 version = (ssl_major << 8) | ssl_minor;
1876 /* sequence number is 64 bits, with top 2 bytes = epoch */
1879 memcpy(&(RECORD_LAYER_get_read_sequence(&s->rlayer)[2]), p, 6);
1885 * Lets check the version. We tolerate alerts that don't have the exact
1886 * version number (e.g. because of protocol version errors)
1888 if (!s->first_packet && rr->type != SSL3_RT_ALERT) {
1889 if (version != s->version) {
1890 /* unexpected version, silently discard */
1892 RECORD_LAYER_reset_packet_length(&s->rlayer);
1897 if ((version & 0xff00) != (s->version & 0xff00)) {
1898 /* wrong version, silently discard record */
1900 RECORD_LAYER_reset_packet_length(&s->rlayer);
1904 if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH) {
1905 /* record too long, silently discard it */
1907 RECORD_LAYER_reset_packet_length(&s->rlayer);
1911 /* If received packet overflows own-client Max Fragment Length setting */
1912 if (s->session != NULL && USE_MAX_FRAGMENT_LENGTH_EXT(s->session)
1913 && rr->length > GET_MAX_FRAGMENT_LENGTH(s->session)) {
1914 /* record too long, silently discard it */
1916 RECORD_LAYER_reset_packet_length(&s->rlayer);
1920 /* now s->rlayer.rstate == SSL_ST_READ_BODY */
1923 /* s->rlayer.rstate == SSL_ST_READ_BODY, get and decode the data */
1926 RECORD_LAYER_get_packet_length(&s->rlayer) - DTLS1_RT_HEADER_LENGTH) {
1927 /* now s->packet_length == DTLS1_RT_HEADER_LENGTH */
1929 rret = ssl3_read_n(s, more, more, 1, 1, &n);
1930 /* this packet contained a partial record, dump it */
1931 if (rret <= 0 || n != more) {
1932 if (ossl_statem_in_error(s)) {
1933 /* ssl3_read_n() called SSLfatal() */
1937 RECORD_LAYER_reset_packet_length(&s->rlayer);
1942 * now n == rr->length, and s->packet_length ==
1943 * DTLS1_RT_HEADER_LENGTH + rr->length
1946 /* set state for later operations */
1947 RECORD_LAYER_set_rstate(&s->rlayer, SSL_ST_READ_HEADER);
1949 /* match epochs. NULL means the packet is dropped on the floor */
1950 bitmap = dtls1_get_bitmap(s, rr, &is_next_epoch);
1951 if (bitmap == NULL) {
1953 RECORD_LAYER_reset_packet_length(&s->rlayer); /* dump this record */
1954 goto again; /* get another record */
1956 #ifndef OPENSSL_NO_SCTP
1957 /* Only do replay check if no SCTP bio */
1958 if (!BIO_dgram_is_sctp(SSL_get_rbio(s))) {
1960 /* Check whether this is a repeat, or aged record. */
1962 * TODO: Does it make sense to have replay protection in epoch 0 where
1963 * we have no integrity negotiated yet?
1965 if (!dtls1_record_replay_check(s, bitmap)) {
1967 RECORD_LAYER_reset_packet_length(&s->rlayer); /* dump this record */
1968 goto again; /* get another record */
1970 #ifndef OPENSSL_NO_SCTP
1974 /* just read a 0 length packet */
1975 if (rr->length == 0)
1979 * If this record is from the next epoch (either HM or ALERT), and a
1980 * handshake is currently in progress, buffer it since it cannot be
1981 * processed at this time.
1983 if (is_next_epoch) {
1984 if ((SSL_in_init(s) || ossl_statem_get_in_handshake(s))) {
1985 if (dtls1_buffer_record (s,
1986 &(DTLS_RECORD_LAYER_get_unprocessed_rcds(&s->rlayer)),
1988 /* SSLfatal() already called */
1993 RECORD_LAYER_reset_packet_length(&s->rlayer);
1997 if (!dtls1_process_record(s, bitmap)) {
1998 if (ossl_statem_in_error(s)) {
1999 /* dtls1_process_record() called SSLfatal */
2003 RECORD_LAYER_reset_packet_length(&s->rlayer); /* dump this record */
2004 goto again; /* get another record */