1 /*
2 * Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved.
3 *
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
8 */
9
10 #include "../ssl_local.h"
11 #include "internal/constant_time.h"
12 #include <openssl/rand.h>
13 #include "record_local.h"
14 #include "internal/cryptlib.h"
15
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
23 };
24
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
32 };
33
34 /*
35 * Clear the contents of an SSL3_RECORD but retain any memory allocated
36 */
SSL3_RECORD_clear(SSL3_RECORD * r,size_t num_recs)37 void SSL3_RECORD_clear(SSL3_RECORD *r, size_t num_recs)
38 {
39 unsigned char *comp;
40 size_t i;
41
42 for (i = 0; i < num_recs; i++) {
43 comp = r[i].comp;
44
45 memset(&r[i], 0, sizeof(*r));
46 r[i].comp = comp;
47 }
48 }
49
SSL3_RECORD_release(SSL3_RECORD * r,size_t num_recs)50 void SSL3_RECORD_release(SSL3_RECORD *r, size_t num_recs)
51 {
52 size_t i;
53
54 for (i = 0; i < num_recs; i++) {
55 OPENSSL_free(r[i].comp);
56 r[i].comp = NULL;
57 }
58 }
59
SSL3_RECORD_set_seq_num(SSL3_RECORD * r,const unsigned char * seq_num)60 void SSL3_RECORD_set_seq_num(SSL3_RECORD *r, const unsigned char *seq_num)
61 {
62 memcpy(r->seq_num, seq_num, SEQ_NUM_SIZE);
63 }
64
65 /*
66 * Peeks ahead into "read_ahead" data to see if we have a whole record waiting
67 * for us in the buffer.
68 */
ssl3_record_app_data_waiting(SSL * s)69 static int ssl3_record_app_data_waiting(SSL *s)
70 {
71 SSL3_BUFFER *rbuf;
72 size_t left, len;
73 unsigned char *p;
74
75 rbuf = RECORD_LAYER_get_rbuf(&s->rlayer);
76
77 p = SSL3_BUFFER_get_buf(rbuf);
78 if (p == NULL)
79 return 0;
80
81 left = SSL3_BUFFER_get_left(rbuf);
82
83 if (left < SSL3_RT_HEADER_LENGTH)
84 return 0;
85
86 p += SSL3_BUFFER_get_offset(rbuf);
87
88 /*
89 * We only check the type and record length, we will sanity check version
90 * etc later
91 */
92 if (*p != SSL3_RT_APPLICATION_DATA)
93 return 0;
94
95 p += 3;
96 n2s(p, len);
97
98 if (left < SSL3_RT_HEADER_LENGTH + len)
99 return 0;
100
101 return 1;
102 }
103
early_data_count_ok(SSL * s,size_t length,size_t overhead,int send)104 int early_data_count_ok(SSL *s, size_t length, size_t overhead, int send)
105 {
106 uint32_t max_early_data;
107 SSL_SESSION *sess = s->session;
108
109 /*
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.
113 */
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);
119 return 0;
120 }
121 sess = s->psksession;
122 }
123
124 if (!s->server)
125 max_early_data = sess->ext.max_early_data;
126 else if (s->ext.early_data != SSL_EARLY_DATA_ACCEPTED)
127 max_early_data = s->recv_max_early_data;
128 else
129 max_early_data = s->recv_max_early_data < sess->ext.max_early_data
130 ? s->recv_max_early_data : sess->ext.max_early_data;
131
132 if (max_early_data == 0) {
133 SSLfatal(s, send ? SSL_AD_INTERNAL_ERROR : SSL_AD_UNEXPECTED_MESSAGE,
134 SSL_F_EARLY_DATA_COUNT_OK, SSL_R_TOO_MUCH_EARLY_DATA);
135 return 0;
136 }
137
138 /* If we are dealing with ciphertext we need to allow for the overhead */
139 max_early_data += overhead;
140
141 if (s->early_data_count + length > max_early_data) {
142 SSLfatal(s, send ? SSL_AD_INTERNAL_ERROR : SSL_AD_UNEXPECTED_MESSAGE,
143 SSL_F_EARLY_DATA_COUNT_OK, SSL_R_TOO_MUCH_EARLY_DATA);
144 return 0;
145 }
146 s->early_data_count += length;
147
148 return 1;
149 }
150
151 /*
152 * MAX_EMPTY_RECORDS defines the number of consecutive, empty records that
153 * will be processed per call to ssl3_get_record. Without this limit an
154 * attacker could send empty records at a faster rate than we can process and
155 * cause ssl3_get_record to loop forever.
156 */
157 #define MAX_EMPTY_RECORDS 32
158
159 #define SSL2_RT_HEADER_LENGTH 2
160 /*-
161 * Call this to get new input records.
162 * It will return <= 0 if more data is needed, normally due to an error
163 * or non-blocking IO.
164 * When it finishes, |numrpipes| records have been decoded. For each record 'i':
165 * rr[i].type - is the type of record
166 * rr[i].data, - data
167 * rr[i].length, - number of bytes
168 * Multiple records will only be returned if the record types are all
169 * SSL3_RT_APPLICATION_DATA. The number of records returned will always be <=
170 * |max_pipelines|
171 */
172 /* used only by ssl3_read_bytes */
ssl3_get_record(SSL * s)173 int ssl3_get_record(SSL *s)
174 {
175 int enc_err, rret;
176 int i;
177 size_t more, n;
178 SSL3_RECORD *rr, *thisrr;
179 SSL3_BUFFER *rbuf;
180 SSL_SESSION *sess;
181 unsigned char *p;
182 unsigned char md[EVP_MAX_MD_SIZE];
183 unsigned int version;
184 size_t mac_size;
185 int imac_size;
186 size_t num_recs = 0, max_recs, j;
187 PACKET pkt, sslv2pkt;
188 size_t first_rec_len;
189 int is_ktls_left;
190
191 rr = RECORD_LAYER_get_rrec(&s->rlayer);
192 rbuf = RECORD_LAYER_get_rbuf(&s->rlayer);
193 is_ktls_left = (rbuf->left > 0);
194 max_recs = s->max_pipelines;
195 if (max_recs == 0)
196 max_recs = 1;
197 sess = s->session;
198
199 do {
200 thisrr = &rr[num_recs];
201
202 /* check if we have the header */
203 if ((RECORD_LAYER_get_rstate(&s->rlayer) != SSL_ST_READ_BODY) ||
204 (RECORD_LAYER_get_packet_length(&s->rlayer)
205 < SSL3_RT_HEADER_LENGTH)) {
206 size_t sslv2len;
207 unsigned int type;
208
209 rret = ssl3_read_n(s, SSL3_RT_HEADER_LENGTH,
210 SSL3_BUFFER_get_len(rbuf), 0,
211 num_recs == 0 ? 1 : 0, &n);
212 if (rret <= 0) {
213 #ifndef OPENSSL_NO_KTLS
214 if (!BIO_get_ktls_recv(s->rbio) || rret == 0)
215 return rret; /* error or non-blocking */
216 switch (errno) {
217 case EBADMSG:
218 SSLfatal(s, SSL_AD_BAD_RECORD_MAC,
219 SSL_F_SSL3_GET_RECORD,
220 SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
221 break;
222 case EMSGSIZE:
223 SSLfatal(s, SSL_AD_RECORD_OVERFLOW,
224 SSL_F_SSL3_GET_RECORD,
225 SSL_R_PACKET_LENGTH_TOO_LONG);
226 break;
227 case EINVAL:
228 SSLfatal(s, SSL_AD_PROTOCOL_VERSION,
229 SSL_F_SSL3_GET_RECORD,
230 SSL_R_WRONG_VERSION_NUMBER);
231 break;
232 default:
233 break;
234 }
235 #endif
236 return rret;
237 }
238 RECORD_LAYER_set_rstate(&s->rlayer, SSL_ST_READ_BODY);
239
240 p = RECORD_LAYER_get_packet(&s->rlayer);
241 if (!PACKET_buf_init(&pkt, RECORD_LAYER_get_packet(&s->rlayer),
242 RECORD_LAYER_get_packet_length(&s->rlayer))) {
243 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_SSL3_GET_RECORD,
244 ERR_R_INTERNAL_ERROR);
245 return -1;
246 }
247 sslv2pkt = pkt;
248 if (!PACKET_get_net_2_len(&sslv2pkt, &sslv2len)
249 || !PACKET_get_1(&sslv2pkt, &type)) {
250 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL3_GET_RECORD,
251 ERR_R_INTERNAL_ERROR);
252 return -1;
253 }
254 /*
255 * The first record received by the server may be a V2ClientHello.
256 */
257 if (s->server && RECORD_LAYER_is_first_record(&s->rlayer)
258 && (sslv2len & 0x8000) != 0
259 && (type == SSL2_MT_CLIENT_HELLO)) {
260 /*
261 * SSLv2 style record
262 *
263 * |num_recs| here will actually always be 0 because
264 * |num_recs > 0| only ever occurs when we are processing
265 * multiple app data records - which we know isn't the case here
266 * because it is an SSLv2ClientHello. We keep it using
267 * |num_recs| for the sake of consistency
268 */
269 thisrr->type = SSL3_RT_HANDSHAKE;
270 thisrr->rec_version = SSL2_VERSION;
271
272 thisrr->length = sslv2len & 0x7fff;
273
274 if (thisrr->length > SSL3_BUFFER_get_len(rbuf)
275 - SSL2_RT_HEADER_LENGTH) {
276 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD,
277 SSL_R_PACKET_LENGTH_TOO_LONG);
278 return -1;
279 }
280
281 if (thisrr->length < MIN_SSL2_RECORD_LEN) {
282 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL3_GET_RECORD,
283 SSL_R_LENGTH_TOO_SHORT);
284 return -1;
285 }
286 } else {
287 /* SSLv3+ style record */
288 if (s->msg_callback)
289 s->msg_callback(0, 0, SSL3_RT_HEADER, p, 5, s,
290 s->msg_callback_arg);
291
292 /* Pull apart the header into the SSL3_RECORD */
293 if (!PACKET_get_1(&pkt, &type)
294 || !PACKET_get_net_2(&pkt, &version)
295 || !PACKET_get_net_2_len(&pkt, &thisrr->length)) {
296 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL3_GET_RECORD,
297 ERR_R_INTERNAL_ERROR);
298 return -1;
299 }
300 thisrr->type = type;
301 thisrr->rec_version = version;
302
303 /*
304 * Lets check version. In TLSv1.3 we only check this field
305 * when encryption is occurring (see later check). For the
306 * ServerHello after an HRR we haven't actually selected TLSv1.3
307 * yet, but we still treat it as TLSv1.3, so we must check for
308 * that explicitly
309 */
310 if (!s->first_packet && !SSL_IS_TLS13(s)
311 && s->hello_retry_request != SSL_HRR_PENDING
312 && version != (unsigned int)s->version) {
313 if ((s->version & 0xFF00) == (version & 0xFF00)
314 && !s->enc_write_ctx && !s->write_hash) {
315 if (thisrr->type == SSL3_RT_ALERT) {
316 /*
317 * The record is using an incorrect version number,
318 * but what we've got appears to be an alert. We
319 * haven't read the body yet to check whether its a
320 * fatal or not - but chances are it is. We probably
321 * shouldn't send a fatal alert back. We'll just
322 * end.
323 */
324 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_SSL3_GET_RECORD,
325 SSL_R_WRONG_VERSION_NUMBER);
326 return -1;
327 }
328 /*
329 * Send back error using their minor version number :-)
330 */
331 s->version = (unsigned short)version;
332 }
333 SSLfatal(s, SSL_AD_PROTOCOL_VERSION, SSL_F_SSL3_GET_RECORD,
334 SSL_R_WRONG_VERSION_NUMBER);
335 return -1;
336 }
337
338 if ((version >> 8) != SSL3_VERSION_MAJOR) {
339 if (RECORD_LAYER_is_first_record(&s->rlayer)) {
340 /* Go back to start of packet, look at the five bytes
341 * that we have. */
342 p = RECORD_LAYER_get_packet(&s->rlayer);
343 if (strncmp((char *)p, "GET ", 4) == 0 ||
344 strncmp((char *)p, "POST ", 5) == 0 ||
345 strncmp((char *)p, "HEAD ", 5) == 0 ||
346 strncmp((char *)p, "PUT ", 4) == 0) {
347 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_SSL3_GET_RECORD,
348 SSL_R_HTTP_REQUEST);
349 return -1;
350 } else if (strncmp((char *)p, "CONNE", 5) == 0) {
351 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_SSL3_GET_RECORD,
352 SSL_R_HTTPS_PROXY_REQUEST);
353 return -1;
354 }
355
356 /* Doesn't look like TLS - don't send an alert */
357 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_SSL3_GET_RECORD,
358 SSL_R_WRONG_VERSION_NUMBER);
359 return -1;
360 } else {
361 SSLfatal(s, SSL_AD_PROTOCOL_VERSION,
362 SSL_F_SSL3_GET_RECORD,
363 SSL_R_WRONG_VERSION_NUMBER);
364 return -1;
365 }
366 }
367
368 if (SSL_IS_TLS13(s) && s->enc_read_ctx != NULL) {
369 if (thisrr->type != SSL3_RT_APPLICATION_DATA
370 && (thisrr->type != SSL3_RT_CHANGE_CIPHER_SPEC
371 || !SSL_IS_FIRST_HANDSHAKE(s))
372 && (thisrr->type != SSL3_RT_ALERT
373 || s->statem.enc_read_state
374 != ENC_READ_STATE_ALLOW_PLAIN_ALERTS)) {
375 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE,
376 SSL_F_SSL3_GET_RECORD, SSL_R_BAD_RECORD_TYPE);
377 return -1;
378 }
379 if (thisrr->rec_version != TLS1_2_VERSION) {
380 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL3_GET_RECORD,
381 SSL_R_WRONG_VERSION_NUMBER);
382 return -1;
383 }
384 }
385
386 if (thisrr->length >
387 SSL3_BUFFER_get_len(rbuf) - SSL3_RT_HEADER_LENGTH) {
388 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD,
389 SSL_R_PACKET_LENGTH_TOO_LONG);
390 return -1;
391 }
392 }
393
394 /* now s->rlayer.rstate == SSL_ST_READ_BODY */
395 }
396
397 if (SSL_IS_TLS13(s)) {
398 if (thisrr->length > SSL3_RT_MAX_TLS13_ENCRYPTED_LENGTH) {
399 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD,
400 SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
401 return -1;
402 }
403 } else {
404 size_t len = SSL3_RT_MAX_ENCRYPTED_LENGTH;
405
406 #ifndef OPENSSL_NO_COMP
407 /*
408 * If OPENSSL_NO_COMP is defined then SSL3_RT_MAX_ENCRYPTED_LENGTH
409 * does not include the compression overhead anyway.
410 */
411 if (s->expand == NULL)
412 len -= SSL3_RT_MAX_COMPRESSED_OVERHEAD;
413 #endif
414
415 if (thisrr->length > len && !BIO_get_ktls_recv(s->rbio)) {
416 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD,
417 SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
418 return -1;
419 }
420 }
421
422 /*
423 * s->rlayer.rstate == SSL_ST_READ_BODY, get and decode the data.
424 * Calculate how much more data we need to read for the rest of the
425 * record
426 */
427 if (thisrr->rec_version == SSL2_VERSION) {
428 more = thisrr->length + SSL2_RT_HEADER_LENGTH
429 - SSL3_RT_HEADER_LENGTH;
430 } else {
431 more = thisrr->length;
432 }
433
434 if (more > 0) {
435 /* now s->rlayer.packet_length == SSL3_RT_HEADER_LENGTH */
436
437 rret = ssl3_read_n(s, more, more, 1, 0, &n);
438 if (rret <= 0)
439 return rret; /* error or non-blocking io */
440 }
441
442 /* set state for later operations */
443 RECORD_LAYER_set_rstate(&s->rlayer, SSL_ST_READ_HEADER);
444
445 /*
446 * At this point, s->rlayer.packet_length == SSL3_RT_HEADER_LENGTH
447 * + thisrr->length, or s->rlayer.packet_length == SSL2_RT_HEADER_LENGTH
448 * + thisrr->length and we have that many bytes in s->rlayer.packet
449 */
450 if (thisrr->rec_version == SSL2_VERSION) {
451 thisrr->input =
452 &(RECORD_LAYER_get_packet(&s->rlayer)[SSL2_RT_HEADER_LENGTH]);
453 } else {
454 thisrr->input =
455 &(RECORD_LAYER_get_packet(&s->rlayer)[SSL3_RT_HEADER_LENGTH]);
456 }
457
458 /*
459 * ok, we can now read from 's->rlayer.packet' data into 'thisrr'.
460 * thisrr->input points at thisrr->length bytes, which need to be copied
461 * into thisrr->data by either the decryption or by the decompression.
462 * When the data is 'copied' into the thisrr->data buffer,
463 * thisrr->input will be updated to point at the new buffer
464 */
465
466 /*
467 * We now have - encrypted [ MAC [ compressed [ plain ] ] ]
468 * thisrr->length bytes of encrypted compressed stuff.
469 */
470
471 /* decrypt in place in 'thisrr->input' */
472 thisrr->data = thisrr->input;
473 thisrr->orig_len = thisrr->length;
474
475 /* Mark this record as not read by upper layers yet */
476 thisrr->read = 0;
477
478 num_recs++;
479
480 /* we have pulled in a full packet so zero things */
481 RECORD_LAYER_reset_packet_length(&s->rlayer);
482 RECORD_LAYER_clear_first_record(&s->rlayer);
483 } while (num_recs < max_recs
484 && thisrr->type == SSL3_RT_APPLICATION_DATA
485 && SSL_USE_EXPLICIT_IV(s)
486 && s->enc_read_ctx != NULL
487 && (EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(s->enc_read_ctx))
488 & EVP_CIPH_FLAG_PIPELINE)
489 && ssl3_record_app_data_waiting(s));
490
491 if (num_recs == 1
492 && thisrr->type == SSL3_RT_CHANGE_CIPHER_SPEC
493 && (SSL_IS_TLS13(s) || s->hello_retry_request != SSL_HRR_NONE)
494 && SSL_IS_FIRST_HANDSHAKE(s)) {
495 /*
496 * CCS messages must be exactly 1 byte long, containing the value 0x01
497 */
498 if (thisrr->length != 1 || thisrr->data[0] != 0x01) {
499 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_SSL3_GET_RECORD,
500 SSL_R_INVALID_CCS_MESSAGE);
501 return -1;
502 }
503 /*
504 * CCS messages are ignored in TLSv1.3. We treat it like an empty
505 * handshake record
506 */
507 thisrr->type = SSL3_RT_HANDSHAKE;
508 RECORD_LAYER_inc_empty_record_count(&s->rlayer);
509 if (RECORD_LAYER_get_empty_record_count(&s->rlayer)
510 > MAX_EMPTY_RECORDS) {
511 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_F_SSL3_GET_RECORD,
512 SSL_R_UNEXPECTED_CCS_MESSAGE);
513 return -1;
514 }
515 thisrr->read = 1;
516 RECORD_LAYER_set_numrpipes(&s->rlayer, 1);
517
518 return 1;
519 }
520
521 /*
522 * KTLS reads full records. If there is any data left,
523 * then it is from before enabling ktls
524 */
525 if (BIO_get_ktls_recv(s->rbio) && !is_ktls_left)
526 goto skip_decryption;
527
528 /*
529 * If in encrypt-then-mac mode calculate mac from encrypted record. All
530 * the details below are public so no timing details can leak.
531 */
532 if (SSL_READ_ETM(s) && s->read_hash) {
533 unsigned char *mac;
534 /* TODO(size_t): convert this to do size_t properly */
535 imac_size = EVP_MD_CTX_size(s->read_hash);
536 if (!ossl_assert(imac_size >= 0 && imac_size <= EVP_MAX_MD_SIZE)) {
537 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_SSL3_GET_RECORD,
538 ERR_LIB_EVP);
539 return -1;
540 }
541 mac_size = (size_t)imac_size;
542 for (j = 0; j < num_recs; j++) {
543 thisrr = &rr[j];
544
545 if (thisrr->length < mac_size) {
546 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL3_GET_RECORD,
547 SSL_R_LENGTH_TOO_SHORT);
548 return -1;
549 }
550 thisrr->length -= mac_size;
551 mac = thisrr->data + thisrr->length;
552 i = s->method->ssl3_enc->mac(s, thisrr, md, 0 /* not send */ );
553 if (i == 0 || CRYPTO_memcmp(md, mac, mac_size) != 0) {
554 SSLfatal(s, SSL_AD_BAD_RECORD_MAC, SSL_F_SSL3_GET_RECORD,
555 SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
556 return -1;
557 }
558 }
559 }
560
561 first_rec_len = rr[0].length;
562
563 enc_err = s->method->ssl3_enc->enc(s, rr, num_recs, 0);
564
565 /*-
566 * enc_err is:
567 * 0: (in non-constant time) if the record is publicly invalid.
568 * 1: if the padding is valid
569 * -1: if the padding is invalid
570 */
571 if (enc_err == 0) {
572 if (ossl_statem_in_error(s)) {
573 /* SSLfatal() already got called */
574 return -1;
575 }
576 if (num_recs == 1 && ossl_statem_skip_early_data(s)) {
577 /*
578 * Valid early_data that we cannot decrypt might fail here as
579 * publicly invalid. We treat it like an empty record.
580 */
581
582 thisrr = &rr[0];
583
584 if (!early_data_count_ok(s, thisrr->length,
585 EARLY_DATA_CIPHERTEXT_OVERHEAD, 0)) {
586 /* SSLfatal() already called */
587 return -1;
588 }
589
590 thisrr->length = 0;
591 thisrr->read = 1;
592 RECORD_LAYER_set_numrpipes(&s->rlayer, 1);
593 RECORD_LAYER_reset_read_sequence(&s->rlayer);
594 return 1;
595 }
596 SSLfatal(s, SSL_AD_BAD_RECORD_MAC, SSL_F_SSL3_GET_RECORD,
597 SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
598 return -1;
599 }
600 #ifdef SSL_DEBUG
601 printf("dec %lu\n", (unsigned long)rr[0].length);
602 {
603 size_t z;
604 for (z = 0; z < rr[0].length; z++)
605 printf("%02X%c", rr[0].data[z], ((z + 1) % 16) ? ' ' : '\n');
606 }
607 printf("\n");
608 #endif
609
610 /* r->length is now the compressed data plus mac */
611 if ((sess != NULL) &&
612 (s->enc_read_ctx != NULL) &&
613 (!SSL_READ_ETM(s) && EVP_MD_CTX_md(s->read_hash) != NULL)) {
614 /* s->read_hash != NULL => mac_size != -1 */
615 unsigned char *mac = NULL;
616 unsigned char mac_tmp[EVP_MAX_MD_SIZE];
617
618 mac_size = EVP_MD_CTX_size(s->read_hash);
619 if (!ossl_assert(mac_size <= EVP_MAX_MD_SIZE)) {
620 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_SSL3_GET_RECORD,
621 ERR_R_INTERNAL_ERROR);
622 return -1;
623 }
624
625 for (j = 0; j < num_recs; j++) {
626 thisrr = &rr[j];
627 /*
628 * orig_len is the length of the record before any padding was
629 * removed. This is public information, as is the MAC in use,
630 * therefore we can safely process the record in a different amount
631 * of time if it's too short to possibly contain a MAC.
632 */
633 if (thisrr->orig_len < mac_size ||
634 /* CBC records must have a padding length byte too. */
635 (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
636 thisrr->orig_len < mac_size + 1)) {
637 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL3_GET_RECORD,
638 SSL_R_LENGTH_TOO_SHORT);
639 return -1;
640 }
641
642 if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE) {
643 /*
644 * We update the length so that the TLS header bytes can be
645 * constructed correctly but we need to extract the MAC in
646 * constant time from within the record, without leaking the
647 * contents of the padding bytes.
648 */
649 mac = mac_tmp;
650 if (!ssl3_cbc_copy_mac(mac_tmp, thisrr, mac_size)) {
651 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_SSL3_GET_RECORD,
652 ERR_R_INTERNAL_ERROR);
653 return -1;
654 }
655 thisrr->length -= mac_size;
656 } else {
657 /*
658 * In this case there's no padding, so |rec->orig_len| equals
659 * |rec->length| and we checked that there's enough bytes for
660 * |mac_size| above.
661 */
662 thisrr->length -= mac_size;
663 mac = &thisrr->data[thisrr->length];
664 }
665
666 i = s->method->ssl3_enc->mac(s, thisrr, md, 0 /* not send */ );
667 if (i == 0 || mac == NULL
668 || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0)
669 enc_err = -1;
670 if (thisrr->length > SSL3_RT_MAX_COMPRESSED_LENGTH + mac_size)
671 enc_err = -1;
672 }
673 }
674
675 if (enc_err < 0) {
676 if (ossl_statem_in_error(s)) {
677 /* We already called SSLfatal() */
678 return -1;
679 }
680 if (num_recs == 1 && ossl_statem_skip_early_data(s)) {
681 /*
682 * We assume this is unreadable early_data - we treat it like an
683 * empty record
684 */
685
686 /*
687 * The record length may have been modified by the mac check above
688 * so we use the previously saved value
689 */
690 if (!early_data_count_ok(s, first_rec_len,
691 EARLY_DATA_CIPHERTEXT_OVERHEAD, 0)) {
692 /* SSLfatal() already called */
693 return -1;
694 }
695
696 thisrr = &rr[0];
697 thisrr->length = 0;
698 thisrr->read = 1;
699 RECORD_LAYER_set_numrpipes(&s->rlayer, 1);
700 RECORD_LAYER_reset_read_sequence(&s->rlayer);
701 return 1;
702 }
703 /*
704 * A separate 'decryption_failed' alert was introduced with TLS 1.0,
705 * SSL 3.0 only has 'bad_record_mac'. But unless a decryption
706 * failure is directly visible from the ciphertext anyway, we should
707 * not reveal which kind of error occurred -- this might become
708 * visible to an attacker (e.g. via a logfile)
709 */
710 SSLfatal(s, SSL_AD_BAD_RECORD_MAC, SSL_F_SSL3_GET_RECORD,
711 SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
712 return -1;
713 }
714
715 skip_decryption:
716
717 for (j = 0; j < num_recs; j++) {
718 thisrr = &rr[j];
719
720 /* thisrr->length is now just compressed */
721 if (s->expand != NULL) {
722 if (thisrr->length > SSL3_RT_MAX_COMPRESSED_LENGTH) {
723 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD,
724 SSL_R_COMPRESSED_LENGTH_TOO_LONG);
725 return -1;
726 }
727 if (!ssl3_do_uncompress(s, thisrr)) {
728 SSLfatal(s, SSL_AD_DECOMPRESSION_FAILURE, SSL_F_SSL3_GET_RECORD,
729 SSL_R_BAD_DECOMPRESSION);
730 return -1;
731 }
732 }
733
734 if (SSL_IS_TLS13(s)
735 && s->enc_read_ctx != NULL
736 && thisrr->type != SSL3_RT_ALERT) {
737 size_t end;
738
739 if (thisrr->length == 0
740 || thisrr->type != SSL3_RT_APPLICATION_DATA) {
741 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_F_SSL3_GET_RECORD,
742 SSL_R_BAD_RECORD_TYPE);
743 return -1;
744 }
745
746 /* Strip trailing padding */
747 for (end = thisrr->length - 1; end > 0 && thisrr->data[end] == 0;
748 end--)
749 continue;
750
751 thisrr->length = end;
752 thisrr->type = thisrr->data[end];
753 if (thisrr->type != SSL3_RT_APPLICATION_DATA
754 && thisrr->type != SSL3_RT_ALERT
755 && thisrr->type != SSL3_RT_HANDSHAKE) {
756 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_F_SSL3_GET_RECORD,
757 SSL_R_BAD_RECORD_TYPE);
758 return -1;
759 }
760 if (s->msg_callback)
761 s->msg_callback(0, s->version, SSL3_RT_INNER_CONTENT_TYPE,
762 &thisrr->data[end], 1, s, s->msg_callback_arg);
763 }
764
765 /*
766 * TLSv1.3 alert and handshake records are required to be non-zero in
767 * length.
768 */
769 if (SSL_IS_TLS13(s)
770 && (thisrr->type == SSL3_RT_HANDSHAKE
771 || thisrr->type == SSL3_RT_ALERT)
772 && thisrr->length == 0) {
773 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_F_SSL3_GET_RECORD,
774 SSL_R_BAD_LENGTH);
775 return -1;
776 }
777
778 if (thisrr->length > SSL3_RT_MAX_PLAIN_LENGTH && !BIO_get_ktls_recv(s->rbio)) {
779 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD,
780 SSL_R_DATA_LENGTH_TOO_LONG);
781 return -1;
782 }
783
784 /* If received packet overflows current Max Fragment Length setting */
785 if (s->session != NULL && USE_MAX_FRAGMENT_LENGTH_EXT(s->session)
786 && thisrr->length > GET_MAX_FRAGMENT_LENGTH(s->session)
787 && !BIO_get_ktls_recv(s->rbio)) {
788 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD,
789 SSL_R_DATA_LENGTH_TOO_LONG);
790 return -1;
791 }
792
793 thisrr->off = 0;
794 /*-
795 * So at this point the following is true
796 * thisrr->type is the type of record
797 * thisrr->length == number of bytes in record
798 * thisrr->off == offset to first valid byte
799 * thisrr->data == where to take bytes from, increment after use :-).
800 */
801
802 /* just read a 0 length packet */
803 if (thisrr->length == 0) {
804 RECORD_LAYER_inc_empty_record_count(&s->rlayer);
805 if (RECORD_LAYER_get_empty_record_count(&s->rlayer)
806 > MAX_EMPTY_RECORDS) {
807 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_F_SSL3_GET_RECORD,
808 SSL_R_RECORD_TOO_SMALL);
809 return -1;
810 }
811 } else {
812 RECORD_LAYER_reset_empty_record_count(&s->rlayer);
813 }
814 }
815
816 if (s->early_data_state == SSL_EARLY_DATA_READING) {
817 thisrr = &rr[0];
818 if (thisrr->type == SSL3_RT_APPLICATION_DATA
819 && !early_data_count_ok(s, thisrr->length, 0, 0)) {
820 /* SSLfatal already called */
821 return -1;
822 }
823 }
824
825 RECORD_LAYER_set_numrpipes(&s->rlayer, num_recs);
826 return 1;
827 }
828
ssl3_do_uncompress(SSL * ssl,SSL3_RECORD * rr)829 int ssl3_do_uncompress(SSL *ssl, SSL3_RECORD *rr)
830 {
831 #ifndef OPENSSL_NO_COMP
832 int i;
833
834 if (rr->comp == NULL) {
835 rr->comp = (unsigned char *)
836 OPENSSL_malloc(SSL3_RT_MAX_ENCRYPTED_LENGTH);
837 }
838 if (rr->comp == NULL)
839 return 0;
840
841 /* TODO(size_t): Convert this call */
842 i = COMP_expand_block(ssl->expand, rr->comp,
843 SSL3_RT_MAX_PLAIN_LENGTH, rr->data, (int)rr->length);
844 if (i < 0)
845 return 0;
846 else
847 rr->length = i;
848 rr->data = rr->comp;
849 #endif
850 return 1;
851 }
852
ssl3_do_compress(SSL * ssl,SSL3_RECORD * wr)853 int ssl3_do_compress(SSL *ssl, SSL3_RECORD *wr)
854 {
855 #ifndef OPENSSL_NO_COMP
856 int i;
857
858 /* TODO(size_t): Convert this call */
859 i = COMP_compress_block(ssl->compress, wr->data,
860 (int)(wr->length + SSL3_RT_MAX_COMPRESSED_OVERHEAD),
861 wr->input, (int)wr->length);
862 if (i < 0)
863 return 0;
864 else
865 wr->length = i;
866
867 wr->input = wr->data;
868 #endif
869 return 1;
870 }
871
872 /*-
873 * ssl3_enc encrypts/decrypts |n_recs| records in |inrecs|. Will call
874 * SSLfatal() for internal errors, but not otherwise.
875 *
876 * Returns:
877 * 0: (in non-constant time) if the record is publicly invalid (i.e. too
878 * short etc).
879 * 1: if the record's padding is valid / the encryption was successful.
880 * -1: if the record's padding is invalid or, if sending, an internal error
881 * occurred.
882 */
ssl3_enc(SSL * s,SSL3_RECORD * inrecs,size_t n_recs,int sending)883 int ssl3_enc(SSL *s, SSL3_RECORD *inrecs, size_t n_recs, int sending)
884 {
885 SSL3_RECORD *rec;
886 EVP_CIPHER_CTX *ds;
887 size_t l, i;
888 size_t bs, mac_size = 0;
889 int imac_size;
890 const EVP_CIPHER *enc;
891
892 rec = inrecs;
893 /*
894 * We shouldn't ever be called with more than one record in the SSLv3 case
895 */
896 if (n_recs != 1)
897 return 0;
898 if (sending) {
899 ds = s->enc_write_ctx;
900 if (s->enc_write_ctx == NULL)
901 enc = NULL;
902 else
903 enc = EVP_CIPHER_CTX_cipher(s->enc_write_ctx);
904 } else {
905 ds = s->enc_read_ctx;
906 if (s->enc_read_ctx == NULL)
907 enc = NULL;
908 else
909 enc = EVP_CIPHER_CTX_cipher(s->enc_read_ctx);
910 }
911
912 if ((s->session == NULL) || (ds == NULL) || (enc == NULL)) {
913 memmove(rec->data, rec->input, rec->length);
914 rec->input = rec->data;
915 } else {
916 l = rec->length;
917 /* TODO(size_t): Convert this call */
918 bs = EVP_CIPHER_CTX_block_size(ds);
919
920 /* COMPRESS */
921
922 if ((bs != 1) && sending) {
923 i = bs - (l % bs);
924
925 /* we need to add 'i-1' padding bytes */
926 l += i;
927 /*
928 * the last of these zero bytes will be overwritten with the
929 * padding length.
930 */
931 memset(&rec->input[rec->length], 0, i);
932 rec->length += i;
933 rec->input[l - 1] = (unsigned char)(i - 1);
934 }
935
936 if (!sending) {
937 if (l == 0 || l % bs != 0)
938 return 0;
939 /* otherwise, rec->length >= bs */
940 }
941
942 /* TODO(size_t): Convert this call */
943 if (EVP_Cipher(ds, rec->data, rec->input, (unsigned int)l) < 1)
944 return -1;
945
946 if (EVP_MD_CTX_md(s->read_hash) != NULL) {
947 /* TODO(size_t): convert me */
948 imac_size = EVP_MD_CTX_size(s->read_hash);
949 if (imac_size < 0) {
950 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_SSL3_ENC,
951 ERR_R_INTERNAL_ERROR);
952 return -1;
953 }
954 mac_size = (size_t)imac_size;
955 }
956 if ((bs != 1) && !sending)
957 return ssl3_cbc_remove_padding(rec, bs, mac_size);
958 }
959 return 1;
960 }
961
962 #define MAX_PADDING 256
963 /*-
964 * tls1_enc encrypts/decrypts |n_recs| in |recs|. Will call SSLfatal() for
965 * internal errors, but not otherwise.
966 *
967 * Returns:
968 * 0: (in non-constant time) if the record is publicly invalid (i.e. too
969 * short etc).
970 * 1: if the record's padding is valid / the encryption was successful.
971 * -1: if the record's padding/AEAD-authenticator is invalid or, if sending,
972 * an internal error occurred.
973 */
tls1_enc(SSL * s,SSL3_RECORD * recs,size_t n_recs,int sending)974 int tls1_enc(SSL *s, SSL3_RECORD *recs, size_t n_recs, int sending)
975 {
976 EVP_CIPHER_CTX *ds;
977 size_t reclen[SSL_MAX_PIPELINES];
978 unsigned char buf[SSL_MAX_PIPELINES][EVP_AEAD_TLS1_AAD_LEN];
979 int i, pad = 0, ret, tmpr;
980 size_t bs, mac_size = 0, ctr, padnum, loop;
981 unsigned char padval;
982 int imac_size;
983 const EVP_CIPHER *enc;
984
985 if (n_recs == 0) {
986 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
987 ERR_R_INTERNAL_ERROR);
988 return 0;
989 }
990
991 if (sending) {
992 if (EVP_MD_CTX_md(s->write_hash)) {
993 int n = EVP_MD_CTX_size(s->write_hash);
994 if (!ossl_assert(n >= 0)) {
995 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
996 ERR_R_INTERNAL_ERROR);
997 return -1;
998 }
999 }
1000 ds = s->enc_write_ctx;
1001 if (s->enc_write_ctx == NULL)
1002 enc = NULL;
1003 else {
1004 int ivlen;
1005 enc = EVP_CIPHER_CTX_cipher(s->enc_write_ctx);
1006 /* For TLSv1.1 and later explicit IV */
1007 if (SSL_USE_EXPLICIT_IV(s)
1008 && EVP_CIPHER_mode(enc) == EVP_CIPH_CBC_MODE)
1009 ivlen = EVP_CIPHER_iv_length(enc);
1010 else
1011 ivlen = 0;
1012 if (ivlen > 1) {
1013 for (ctr = 0; ctr < n_recs; ctr++) {
1014 if (recs[ctr].data != recs[ctr].input) {
1015 /*
1016 * we can't write into the input stream: Can this ever
1017 * happen?? (steve)
1018 */
1019 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
1020 ERR_R_INTERNAL_ERROR);
1021 return -1;
1022 } else if (RAND_bytes(recs[ctr].input, ivlen) <= 0) {
1023 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
1024 ERR_R_INTERNAL_ERROR);
1025 return -1;
1026 }
1027 }
1028 }
1029 }
1030 } else {
1031 if (EVP_MD_CTX_md(s->read_hash)) {
1032 int n = EVP_MD_CTX_size(s->read_hash);
1033 if (!ossl_assert(n >= 0)) {
1034 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
1035 ERR_R_INTERNAL_ERROR);
1036 return -1;
1037 }
1038 }
1039 ds = s->enc_read_ctx;
1040 if (s->enc_read_ctx == NULL)
1041 enc = NULL;
1042 else
1043 enc = EVP_CIPHER_CTX_cipher(s->enc_read_ctx);
1044 }
1045
1046 if ((s->session == NULL) || (ds == NULL) || (enc == NULL)) {
1047 for (ctr = 0; ctr < n_recs; ctr++) {
1048 memmove(recs[ctr].data, recs[ctr].input, recs[ctr].length);
1049 recs[ctr].input = recs[ctr].data;
1050 }
1051 ret = 1;
1052 } else {
1053 bs = EVP_CIPHER_block_size(EVP_CIPHER_CTX_cipher(ds));
1054
1055 if (n_recs > 1) {
1056 if (!(EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(ds))
1057 & EVP_CIPH_FLAG_PIPELINE)) {
1058 /*
1059 * We shouldn't have been called with pipeline data if the
1060 * cipher doesn't support pipelining
1061 */
1062 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
1063 SSL_R_PIPELINE_FAILURE);
1064 return -1;
1065 }
1066 }
1067 for (ctr = 0; ctr < n_recs; ctr++) {
1068 reclen[ctr] = recs[ctr].length;
1069
1070 if (EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(ds))
1071 & EVP_CIPH_FLAG_AEAD_CIPHER) {
1072 unsigned char *seq;
1073
1074 seq = sending ? RECORD_LAYER_get_write_sequence(&s->rlayer)
1075 : RECORD_LAYER_get_read_sequence(&s->rlayer);
1076
1077 if (SSL_IS_DTLS(s)) {
1078 /* DTLS does not support pipelining */
1079 unsigned char dtlsseq[8], *p = dtlsseq;
1080
1081 s2n(sending ? DTLS_RECORD_LAYER_get_w_epoch(&s->rlayer) :
1082 DTLS_RECORD_LAYER_get_r_epoch(&s->rlayer), p);
1083 memcpy(p, &seq[2], 6);
1084 memcpy(buf[ctr], dtlsseq, 8);
1085 } else {
1086 memcpy(buf[ctr], seq, 8);
1087 for (i = 7; i >= 0; i--) { /* increment */
1088 ++seq[i];
1089 if (seq[i] != 0)
1090 break;
1091 }
1092 }
1093
1094 buf[ctr][8] = recs[ctr].type;
1095 buf[ctr][9] = (unsigned char)(s->version >> 8);
1096 buf[ctr][10] = (unsigned char)(s->version);
1097 buf[ctr][11] = (unsigned char)(recs[ctr].length >> 8);
1098 buf[ctr][12] = (unsigned char)(recs[ctr].length & 0xff);
1099 pad = EVP_CIPHER_CTX_ctrl(ds, EVP_CTRL_AEAD_TLS1_AAD,
1100 EVP_AEAD_TLS1_AAD_LEN, buf[ctr]);
1101 if (pad <= 0) {
1102 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
1103 ERR_R_INTERNAL_ERROR);
1104 return -1;
1105 }
1106
1107 if (sending) {
1108 reclen[ctr] += pad;
1109 recs[ctr].length += pad;
1110 }
1111
1112 } else if ((bs != 1) && sending) {
1113 padnum = bs - (reclen[ctr] % bs);
1114
1115 /* Add weird padding of up to 256 bytes */
1116
1117 if (padnum > MAX_PADDING) {
1118 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
1119 ERR_R_INTERNAL_ERROR);
1120 return -1;
1121 }
1122 /* we need to add 'padnum' padding bytes of value padval */
1123 padval = (unsigned char)(padnum - 1);
1124 for (loop = reclen[ctr]; loop < reclen[ctr] + padnum; loop++)
1125 recs[ctr].input[loop] = padval;
1126 reclen[ctr] += padnum;
1127 recs[ctr].length += padnum;
1128 }
1129
1130 if (!sending) {
1131 if (reclen[ctr] == 0 || reclen[ctr] % bs != 0)
1132 return 0;
1133 }
1134 }
1135 if (n_recs > 1) {
1136 unsigned char *data[SSL_MAX_PIPELINES];
1137
1138 /* Set the output buffers */
1139 for (ctr = 0; ctr < n_recs; ctr++) {
1140 data[ctr] = recs[ctr].data;
1141 }
1142 if (EVP_CIPHER_CTX_ctrl(ds, EVP_CTRL_SET_PIPELINE_OUTPUT_BUFS,
1143 (int)n_recs, data) <= 0) {
1144 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
1145 SSL_R_PIPELINE_FAILURE);
1146 return -1;
1147 }
1148 /* Set the input buffers */
1149 for (ctr = 0; ctr < n_recs; ctr++) {
1150 data[ctr] = recs[ctr].input;
1151 }
1152 if (EVP_CIPHER_CTX_ctrl(ds, EVP_CTRL_SET_PIPELINE_INPUT_BUFS,
1153 (int)n_recs, data) <= 0
1154 || EVP_CIPHER_CTX_ctrl(ds, EVP_CTRL_SET_PIPELINE_INPUT_LENS,
1155 (int)n_recs, reclen) <= 0) {
1156 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
1157 SSL_R_PIPELINE_FAILURE);
1158 return -1;
1159 }
1160 }
1161
1162 /* TODO(size_t): Convert this call */
1163 tmpr = EVP_Cipher(ds, recs[0].data, recs[0].input,
1164 (unsigned int)reclen[0]);
1165 if ((EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(ds))
1166 & EVP_CIPH_FLAG_CUSTOM_CIPHER)
1167 ? (tmpr < 0)
1168 : (tmpr == 0))
1169 return -1; /* AEAD can fail to verify MAC */
1170
1171 if (sending == 0) {
1172 if (EVP_CIPHER_mode(enc) == EVP_CIPH_GCM_MODE) {
1173 for (ctr = 0; ctr < n_recs; ctr++) {
1174 recs[ctr].data += EVP_GCM_TLS_EXPLICIT_IV_LEN;
1175 recs[ctr].input += EVP_GCM_TLS_EXPLICIT_IV_LEN;
1176 recs[ctr].length -= EVP_GCM_TLS_EXPLICIT_IV_LEN;
1177 }
1178 } else if (EVP_CIPHER_mode(enc) == EVP_CIPH_CCM_MODE) {
1179 for (ctr = 0; ctr < n_recs; ctr++) {
1180 recs[ctr].data += EVP_CCM_TLS_EXPLICIT_IV_LEN;
1181 recs[ctr].input += EVP_CCM_TLS_EXPLICIT_IV_LEN;
1182 recs[ctr].length -= EVP_CCM_TLS_EXPLICIT_IV_LEN;
1183 }
1184 }
1185 }
1186
1187 ret = 1;
1188 if (!SSL_READ_ETM(s) && EVP_MD_CTX_md(s->read_hash) != NULL) {
1189 imac_size = EVP_MD_CTX_size(s->read_hash);
1190 if (imac_size < 0) {
1191 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC,
1192 ERR_R_INTERNAL_ERROR);
1193 return -1;
1194 }
1195 mac_size = (size_t)imac_size;
1196 }
1197 if ((bs != 1) && !sending) {
1198 int tmpret;
1199 for (ctr = 0; ctr < n_recs; ctr++) {
1200 tmpret = tls1_cbc_remove_padding(s, &recs[ctr], bs, mac_size);
1201 /*
1202 * If tmpret == 0 then this means publicly invalid so we can
1203 * short circuit things here. Otherwise we must respect constant
1204 * time behaviour.
1205 */
1206 if (tmpret == 0)
1207 return 0;
1208 ret = constant_time_select_int(constant_time_eq_int(tmpret, 1),
1209 ret, -1);
1210 }
1211 }
1212 if (pad && !sending) {
1213 for (ctr = 0; ctr < n_recs; ctr++) {
1214 recs[ctr].length -= pad;
1215 }
1216 }
1217 }
1218 return ret;
1219 }
1220
n_ssl3_mac(SSL * ssl,SSL3_RECORD * rec,unsigned char * md,int sending)1221 int n_ssl3_mac(SSL *ssl, SSL3_RECORD *rec, unsigned char *md, int sending)
1222 {
1223 unsigned char *mac_sec, *seq;
1224 const EVP_MD_CTX *hash;
1225 unsigned char *p, rec_char;
1226 size_t md_size;
1227 size_t npad;
1228 int t;
1229
1230 if (sending) {
1231 mac_sec = &(ssl->s3->write_mac_secret[0]);
1232 seq = RECORD_LAYER_get_write_sequence(&ssl->rlayer);
1233 hash = ssl->write_hash;
1234 } else {
1235 mac_sec = &(ssl->s3->read_mac_secret[0]);
1236 seq = RECORD_LAYER_get_read_sequence(&ssl->rlayer);
1237 hash = ssl->read_hash;
1238 }
1239
1240 t = EVP_MD_CTX_size(hash);
1241 if (t < 0)
1242 return 0;
1243 md_size = t;
1244 npad = (48 / md_size) * md_size;
1245
1246 if (!sending &&
1247 EVP_CIPHER_CTX_mode(ssl->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
1248 ssl3_cbc_record_digest_supported(hash)) {
1249 /*
1250 * This is a CBC-encrypted record. We must avoid leaking any
1251 * timing-side channel information about how many blocks of data we
1252 * are hashing because that gives an attacker a timing-oracle.
1253 */
1254
1255 /*-
1256 * npad is, at most, 48 bytes and that's with MD5:
1257 * 16 + 48 + 8 (sequence bytes) + 1 + 2 = 75.
1258 *
1259 * With SHA-1 (the largest hash speced for SSLv3) the hash size
1260 * goes up 4, but npad goes down by 8, resulting in a smaller
1261 * total size.
1262 */
1263 unsigned char header[75];
1264 size_t j = 0;
1265 memcpy(header + j, mac_sec, md_size);
1266 j += md_size;
1267 memcpy(header + j, ssl3_pad_1, npad);
1268 j += npad;
1269 memcpy(header + j, seq, 8);
1270 j += 8;
1271 header[j++] = rec->type;
1272 header[j++] = (unsigned char)(rec->length >> 8);
1273 header[j++] = (unsigned char)(rec->length & 0xff);
1274
1275 /* Final param == is SSLv3 */
1276 if (ssl3_cbc_digest_record(hash,
1277 md, &md_size,
1278 header, rec->input,
1279 rec->length + md_size, rec->orig_len,
1280 mac_sec, md_size, 1) <= 0)
1281 return 0;
1282 } else {
1283 unsigned int md_size_u;
1284 /* Chop the digest off the end :-) */
1285 EVP_MD_CTX *md_ctx = EVP_MD_CTX_new();
1286
1287 if (md_ctx == NULL)
1288 return 0;
1289
1290 rec_char = rec->type;
1291 p = md;
1292 s2n(rec->length, p);
1293 if (EVP_MD_CTX_copy_ex(md_ctx, hash) <= 0
1294 || EVP_DigestUpdate(md_ctx, mac_sec, md_size) <= 0
1295 || EVP_DigestUpdate(md_ctx, ssl3_pad_1, npad) <= 0
1296 || EVP_DigestUpdate(md_ctx, seq, 8) <= 0
1297 || EVP_DigestUpdate(md_ctx, &rec_char, 1) <= 0
1298 || EVP_DigestUpdate(md_ctx, md, 2) <= 0
1299 || EVP_DigestUpdate(md_ctx, rec->input, rec->length) <= 0
1300 || EVP_DigestFinal_ex(md_ctx, md, NULL) <= 0
1301 || EVP_MD_CTX_copy_ex(md_ctx, hash) <= 0
1302 || EVP_DigestUpdate(md_ctx, mac_sec, md_size) <= 0
1303 || EVP_DigestUpdate(md_ctx, ssl3_pad_2, npad) <= 0
1304 || EVP_DigestUpdate(md_ctx, md, md_size) <= 0
1305 || EVP_DigestFinal_ex(md_ctx, md, &md_size_u) <= 0) {
1306 EVP_MD_CTX_free(md_ctx);
1307 return 0;
1308 }
1309
1310 EVP_MD_CTX_free(md_ctx);
1311 }
1312
1313 ssl3_record_sequence_update(seq);
1314 return 1;
1315 }
1316
tls1_mac(SSL * ssl,SSL3_RECORD * rec,unsigned char * md,int sending)1317 int tls1_mac(SSL *ssl, SSL3_RECORD *rec, unsigned char *md, int sending)
1318 {
1319 unsigned char *seq;
1320 EVP_MD_CTX *hash;
1321 size_t md_size;
1322 int i;
1323 EVP_MD_CTX *hmac = NULL, *mac_ctx;
1324 unsigned char header[13];
1325 int stream_mac = (sending ? (ssl->mac_flags & SSL_MAC_FLAG_WRITE_MAC_STREAM)
1326 : (ssl->mac_flags & SSL_MAC_FLAG_READ_MAC_STREAM));
1327 int t;
1328
1329 if (sending) {
1330 seq = RECORD_LAYER_get_write_sequence(&ssl->rlayer);
1331 hash = ssl->write_hash;
1332 } else {
1333 seq = RECORD_LAYER_get_read_sequence(&ssl->rlayer);
1334 hash = ssl->read_hash;
1335 }
1336
1337 t = EVP_MD_CTX_size(hash);
1338 if (!ossl_assert(t >= 0))
1339 return 0;
1340 md_size = t;
1341
1342 /* I should fix this up TLS TLS TLS TLS TLS XXXXXXXX */
1343 if (stream_mac) {
1344 mac_ctx = hash;
1345 } else {
1346 hmac = EVP_MD_CTX_new();
1347 if (hmac == NULL || !EVP_MD_CTX_copy(hmac, hash)) {
1348 EVP_MD_CTX_free(hmac);
1349 return 0;
1350 }
1351 mac_ctx = hmac;
1352 }
1353
1354 if (SSL_IS_DTLS(ssl)) {
1355 unsigned char dtlsseq[8], *p = dtlsseq;
1356
1357 s2n(sending ? DTLS_RECORD_LAYER_get_w_epoch(&ssl->rlayer) :
1358 DTLS_RECORD_LAYER_get_r_epoch(&ssl->rlayer), p);
1359 memcpy(p, &seq[2], 6);
1360
1361 memcpy(header, dtlsseq, 8);
1362 } else
1363 memcpy(header, seq, 8);
1364
1365 header[8] = rec->type;
1366 header[9] = (unsigned char)(ssl->version >> 8);
1367 header[10] = (unsigned char)(ssl->version);
1368 header[11] = (unsigned char)(rec->length >> 8);
1369 header[12] = (unsigned char)(rec->length & 0xff);
1370
1371 if (!sending && !SSL_READ_ETM(ssl) &&
1372 EVP_CIPHER_CTX_mode(ssl->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
1373 ssl3_cbc_record_digest_supported(mac_ctx)) {
1374 /*
1375 * This is a CBC-encrypted record. We must avoid leaking any
1376 * timing-side channel information about how many blocks of data we
1377 * are hashing because that gives an attacker a timing-oracle.
1378 */
1379 /* Final param == not SSLv3 */
1380 if (ssl3_cbc_digest_record(mac_ctx,
1381 md, &md_size,
1382 header, rec->input,
1383 rec->length + md_size, rec->orig_len,
1384 ssl->s3->read_mac_secret,
1385 ssl->s3->read_mac_secret_size, 0) <= 0) {
1386 EVP_MD_CTX_free(hmac);
1387 return 0;
1388 }
1389 } else {
1390 /* TODO(size_t): Convert these calls */
1391 if (EVP_DigestSignUpdate(mac_ctx, header, sizeof(header)) <= 0
1392 || EVP_DigestSignUpdate(mac_ctx, rec->input, rec->length) <= 0
1393 || EVP_DigestSignFinal(mac_ctx, md, &md_size) <= 0) {
1394 EVP_MD_CTX_free(hmac);
1395 return 0;
1396 }
1397 }
1398
1399 EVP_MD_CTX_free(hmac);
1400
1401 #ifdef SSL_DEBUG
1402 fprintf(stderr, "seq=");
1403 {
1404 int z;
1405 for (z = 0; z < 8; z++)
1406 fprintf(stderr, "%02X ", seq[z]);
1407 fprintf(stderr, "\n");
1408 }
1409 fprintf(stderr, "rec=");
1410 {
1411 size_t z;
1412 for (z = 0; z < rec->length; z++)
1413 fprintf(stderr, "%02X ", rec->data[z]);
1414 fprintf(stderr, "\n");
1415 }
1416 #endif
1417
1418 if (!SSL_IS_DTLS(ssl)) {
1419 for (i = 7; i >= 0; i--) {
1420 ++seq[i];
1421 if (seq[i] != 0)
1422 break;
1423 }
1424 }
1425 #ifdef SSL_DEBUG
1426 {
1427 unsigned int z;
1428 for (z = 0; z < md_size; z++)
1429 fprintf(stderr, "%02X ", md[z]);
1430 fprintf(stderr, "\n");
1431 }
1432 #endif
1433 return 1;
1434 }
1435
1436 /*-
1437 * ssl3_cbc_remove_padding removes padding from the decrypted, SSLv3, CBC
1438 * record in |rec| by updating |rec->length| in constant time.
1439 *
1440 * block_size: the block size of the cipher used to encrypt the record.
1441 * returns:
1442 * 0: (in non-constant time) if the record is publicly invalid.
1443 * 1: if the padding was valid
1444 * -1: otherwise.
1445 */
ssl3_cbc_remove_padding(SSL3_RECORD * rec,size_t block_size,size_t mac_size)1446 int ssl3_cbc_remove_padding(SSL3_RECORD *rec,
1447 size_t block_size, size_t mac_size)
1448 {
1449 size_t padding_length;
1450 size_t good;
1451 const size_t overhead = 1 /* padding length byte */ + mac_size;
1452
1453 /*
1454 * These lengths are all public so we can test them in non-constant time.
1455 */
1456 if (overhead > rec->length)
1457 return 0;
1458
1459 padding_length = rec->data[rec->length - 1];
1460 good = constant_time_ge_s(rec->length, padding_length + overhead);
1461 /* SSLv3 requires that the padding is minimal. */
1462 good &= constant_time_ge_s(block_size, padding_length + 1);
1463 rec->length -= good & (padding_length + 1);
1464 return constant_time_select_int_s(good, 1, -1);
1465 }
1466
1467 /*-
1468 * tls1_cbc_remove_padding removes the CBC padding from the decrypted, TLS, CBC
1469 * record in |rec| in constant time and returns 1 if the padding is valid and
1470 * -1 otherwise. It also removes any explicit IV from the start of the record
1471 * without leaking any timing about whether there was enough space after the
1472 * padding was removed.
1473 *
1474 * block_size: the block size of the cipher used to encrypt the record.
1475 * returns:
1476 * 0: (in non-constant time) if the record is publicly invalid.
1477 * 1: if the padding was valid
1478 * -1: otherwise.
1479 */
tls1_cbc_remove_padding(const SSL * s,SSL3_RECORD * rec,size_t block_size,size_t mac_size)1480 int tls1_cbc_remove_padding(const SSL *s,
1481 SSL3_RECORD *rec,
1482 size_t block_size, size_t mac_size)
1483 {
1484 size_t good;
1485 size_t padding_length, to_check, i;
1486 const size_t overhead = 1 /* padding length byte */ + mac_size;
1487 /* Check if version requires explicit IV */
1488 if (SSL_USE_EXPLICIT_IV(s)) {
1489 /*
1490 * These lengths are all public so we can test them in non-constant
1491 * time.
1492 */
1493 if (overhead + block_size > rec->length)
1494 return 0;
1495 /* We can now safely skip explicit IV */
1496 rec->data += block_size;
1497 rec->input += block_size;
1498 rec->length -= block_size;
1499 rec->orig_len -= block_size;
1500 } else if (overhead > rec->length)
1501 return 0;
1502
1503 padding_length = rec->data[rec->length - 1];
1504
1505 if (EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(s->enc_read_ctx)) &
1506 EVP_CIPH_FLAG_AEAD_CIPHER) {
1507 /* padding is already verified */
1508 rec->length -= padding_length + 1;
1509 return 1;
1510 }
1511
1512 good = constant_time_ge_s(rec->length, overhead + padding_length);
1513 /*
1514 * The padding consists of a length byte at the end of the record and
1515 * then that many bytes of padding, all with the same value as the length
1516 * byte. Thus, with the length byte included, there are i+1 bytes of
1517 * padding. We can't check just |padding_length+1| bytes because that
1518 * leaks decrypted information. Therefore we always have to check the
1519 * maximum amount of padding possible. (Again, the length of the record
1520 * is public information so we can use it.)
1521 */
1522 to_check = 256; /* maximum amount of padding, inc length byte. */
1523 if (to_check > rec->length)
1524 to_check = rec->length;
1525
1526 for (i = 0; i < to_check; i++) {
1527 unsigned char mask = constant_time_ge_8_s(padding_length, i);
1528 unsigned char b = rec->data[rec->length - 1 - i];
1529 /*
1530 * The final |padding_length+1| bytes should all have the value
1531 * |padding_length|. Therefore the XOR should be zero.
1532 */
1533 good &= ~(mask & (padding_length ^ b));
1534 }
1535
1536 /*
1537 * If any of the final |padding_length+1| bytes had the wrong value, one
1538 * or more of the lower eight bits of |good| will be cleared.
1539 */
1540 good = constant_time_eq_s(0xff, good & 0xff);
1541 rec->length -= good & (padding_length + 1);
1542
1543 return constant_time_select_int_s(good, 1, -1);
1544 }
1545
1546 /*-
1547 * ssl3_cbc_copy_mac copies |md_size| bytes from the end of |rec| to |out| in
1548 * constant time (independent of the concrete value of rec->length, which may
1549 * vary within a 256-byte window).
1550 *
1551 * ssl3_cbc_remove_padding or tls1_cbc_remove_padding must be called prior to
1552 * this function.
1553 *
1554 * On entry:
1555 * rec->orig_len >= md_size
1556 * md_size <= EVP_MAX_MD_SIZE
1557 *
1558 * If CBC_MAC_ROTATE_IN_PLACE is defined then the rotation is performed with
1559 * variable accesses in a 64-byte-aligned buffer. Assuming that this fits into
1560 * a single or pair of cache-lines, then the variable memory accesses don't
1561 * actually affect the timing. CPUs with smaller cache-lines [if any] are
1562 * not multi-core and are not considered vulnerable to cache-timing attacks.
1563 */
1564 #define CBC_MAC_ROTATE_IN_PLACE
1565
ssl3_cbc_copy_mac(unsigned char * out,const SSL3_RECORD * rec,size_t md_size)1566 int ssl3_cbc_copy_mac(unsigned char *out,
1567 const SSL3_RECORD *rec, size_t md_size)
1568 {
1569 #if defined(CBC_MAC_ROTATE_IN_PLACE)
1570 unsigned char rotated_mac_buf[64 + EVP_MAX_MD_SIZE];
1571 unsigned char *rotated_mac;
1572 #else
1573 unsigned char rotated_mac[EVP_MAX_MD_SIZE];
1574 #endif
1575
1576 /*
1577 * mac_end is the index of |rec->data| just after the end of the MAC.
1578 */
1579 size_t mac_end = rec->length;
1580 size_t mac_start = mac_end - md_size;
1581 size_t in_mac;
1582 /*
1583 * scan_start contains the number of bytes that we can ignore because the
1584 * MAC's position can only vary by 255 bytes.
1585 */
1586 size_t scan_start = 0;
1587 size_t i, j;
1588 size_t rotate_offset;
1589
1590 if (!ossl_assert(rec->orig_len >= md_size
1591 && md_size <= EVP_MAX_MD_SIZE))
1592 return 0;
1593
1594 #if defined(CBC_MAC_ROTATE_IN_PLACE)
1595 rotated_mac = rotated_mac_buf + ((0 - (size_t)rotated_mac_buf) & 63);
1596 #endif
1597
1598 /* This information is public so it's safe to branch based on it. */
1599 if (rec->orig_len > md_size + 255 + 1)
1600 scan_start = rec->orig_len - (md_size + 255 + 1);
1601
1602 in_mac = 0;
1603 rotate_offset = 0;
1604 memset(rotated_mac, 0, md_size);
1605 for (i = scan_start, j = 0; i < rec->orig_len; i++) {
1606 size_t mac_started = constant_time_eq_s(i, mac_start);
1607 size_t mac_ended = constant_time_lt_s(i, mac_end);
1608 unsigned char b = rec->data[i];
1609
1610 in_mac |= mac_started;
1611 in_mac &= mac_ended;
1612 rotate_offset |= j & mac_started;
1613 rotated_mac[j++] |= b & in_mac;
1614 j &= constant_time_lt_s(j, md_size);
1615 }
1616
1617 /* Now rotate the MAC */
1618 #if defined(CBC_MAC_ROTATE_IN_PLACE)
1619 j = 0;
1620 for (i = 0; i < md_size; i++) {
1621 /* in case cache-line is 32 bytes, touch second line */
1622 ((volatile unsigned char *)rotated_mac)[rotate_offset ^ 32];
1623 out[j++] = rotated_mac[rotate_offset++];
1624 rotate_offset &= constant_time_lt_s(rotate_offset, md_size);
1625 }
1626 #else
1627 memset(out, 0, md_size);
1628 rotate_offset = md_size - rotate_offset;
1629 rotate_offset &= constant_time_lt_s(rotate_offset, md_size);
1630 for (i = 0; i < md_size; i++) {
1631 for (j = 0; j < md_size; j++)
1632 out[j] |= rotated_mac[i] & constant_time_eq_8_s(j, rotate_offset);
1633 rotate_offset++;
1634 rotate_offset &= constant_time_lt_s(rotate_offset, md_size);
1635 }
1636 #endif
1637
1638 return 1;
1639 }
1640
dtls1_process_record(SSL * s,DTLS1_BITMAP * bitmap)1641 int dtls1_process_record(SSL *s, DTLS1_BITMAP *bitmap)
1642 {
1643 int i;
1644 int enc_err;
1645 SSL_SESSION *sess;
1646 SSL3_RECORD *rr;
1647 int imac_size;
1648 size_t mac_size;
1649 unsigned char md[EVP_MAX_MD_SIZE];
1650 size_t max_plain_length = SSL3_RT_MAX_PLAIN_LENGTH;
1651
1652 rr = RECORD_LAYER_get_rrec(&s->rlayer);
1653 sess = s->session;
1654
1655 /*
1656 * At this point, s->rlayer.packet_length == SSL3_RT_HEADER_LNGTH + rr->length,
1657 * and we have that many bytes in s->rlayer.packet
1658 */
1659 rr->input = &(RECORD_LAYER_get_packet(&s->rlayer)[DTLS1_RT_HEADER_LENGTH]);
1660
1661 /*
1662 * ok, we can now read from 's->rlayer.packet' data into 'rr'. rr->input
1663 * points at rr->length bytes, which need to be copied into rr->data by
1664 * either the decryption or by the decompression. When the data is 'copied'
1665 * into the rr->data buffer, rr->input will be pointed at the new buffer
1666 */
1667
1668 /*
1669 * We now have - encrypted [ MAC [ compressed [ plain ] ] ] rr->length
1670 * bytes of encrypted compressed stuff.
1671 */
1672
1673 /* check is not needed I believe */
1674 if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH) {
1675 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_DTLS1_PROCESS_RECORD,
1676 SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
1677 return 0;
1678 }
1679
1680 /* decrypt in place in 'rr->input' */
1681 rr->data = rr->input;
1682 rr->orig_len = rr->length;
1683
1684 if (SSL_READ_ETM(s) && s->read_hash) {
1685 unsigned char *mac;
1686 mac_size = EVP_MD_CTX_size(s->read_hash);
1687 if (!ossl_assert(mac_size <= EVP_MAX_MD_SIZE)) {
1688 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DTLS1_PROCESS_RECORD,
1689 ERR_R_INTERNAL_ERROR);
1690 return 0;
1691 }
1692 if (rr->orig_len < mac_size) {
1693 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_DTLS1_PROCESS_RECORD,
1694 SSL_R_LENGTH_TOO_SHORT);
1695 return 0;
1696 }
1697 rr->length -= mac_size;
1698 mac = rr->data + rr->length;
1699 i = s->method->ssl3_enc->mac(s, rr, md, 0 /* not send */ );
1700 if (i == 0 || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0) {
1701 SSLfatal(s, SSL_AD_BAD_RECORD_MAC, SSL_F_DTLS1_PROCESS_RECORD,
1702 SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
1703 return 0;
1704 }
1705 }
1706
1707 enc_err = s->method->ssl3_enc->enc(s, rr, 1, 0);
1708 /*-
1709 * enc_err is:
1710 * 0: (in non-constant time) if the record is publicly invalid.
1711 * 1: if the padding is valid
1712 * -1: if the padding is invalid
1713 */
1714 if (enc_err == 0) {
1715 if (ossl_statem_in_error(s)) {
1716 /* SSLfatal() got called */
1717 return 0;
1718 }
1719 /* For DTLS we simply ignore bad packets. */
1720 rr->length = 0;
1721 RECORD_LAYER_reset_packet_length(&s->rlayer);
1722 return 0;
1723 }
1724 #ifdef SSL_DEBUG
1725 printf("dec %ld\n", rr->length);
1726 {
1727 size_t z;
1728 for (z = 0; z < rr->length; z++)
1729 printf("%02X%c", rr->data[z], ((z + 1) % 16) ? ' ' : '\n');
1730 }
1731 printf("\n");
1732 #endif
1733
1734 /* r->length is now the compressed data plus mac */
1735 if ((sess != NULL) && !SSL_READ_ETM(s) &&
1736 (s->enc_read_ctx != NULL) && (EVP_MD_CTX_md(s->read_hash) != NULL)) {
1737 /* s->read_hash != NULL => mac_size != -1 */
1738 unsigned char *mac = NULL;
1739 unsigned char mac_tmp[EVP_MAX_MD_SIZE];
1740
1741 /* TODO(size_t): Convert this to do size_t properly */
1742 imac_size = EVP_MD_CTX_size(s->read_hash);
1743 if (imac_size < 0) {
1744 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DTLS1_PROCESS_RECORD,
1745 ERR_LIB_EVP);
1746 return 0;
1747 }
1748 mac_size = (size_t)imac_size;
1749 if (!ossl_assert(mac_size <= EVP_MAX_MD_SIZE)) {
1750 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DTLS1_PROCESS_RECORD,
1751 ERR_R_INTERNAL_ERROR);
1752 return 0;
1753 }
1754
1755 /*
1756 * orig_len is the length of the record before any padding was
1757 * removed. This is public information, as is the MAC in use,
1758 * therefore we can safely process the record in a different amount
1759 * of time if it's too short to possibly contain a MAC.
1760 */
1761 if (rr->orig_len < mac_size ||
1762 /* CBC records must have a padding length byte too. */
1763 (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
1764 rr->orig_len < mac_size + 1)) {
1765 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_DTLS1_PROCESS_RECORD,
1766 SSL_R_LENGTH_TOO_SHORT);
1767 return 0;
1768 }
1769
1770 if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE) {
1771 /*
1772 * We update the length so that the TLS header bytes can be
1773 * constructed correctly but we need to extract the MAC in
1774 * constant time from within the record, without leaking the
1775 * contents of the padding bytes.
1776 */
1777 mac = mac_tmp;
1778 if (!ssl3_cbc_copy_mac(mac_tmp, rr, mac_size)) {
1779 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DTLS1_PROCESS_RECORD,
1780 ERR_R_INTERNAL_ERROR);
1781 return 0;
1782 }
1783 rr->length -= mac_size;
1784 } else {
1785 /*
1786 * In this case there's no padding, so |rec->orig_len| equals
1787 * |rec->length| and we checked that there's enough bytes for
1788 * |mac_size| above.
1789 */
1790 rr->length -= mac_size;
1791 mac = &rr->data[rr->length];
1792 }
1793
1794 i = s->method->ssl3_enc->mac(s, rr, md, 0 /* not send */ );
1795 if (i == 0 || mac == NULL
1796 || CRYPTO_memcmp(md, mac, mac_size) != 0)
1797 enc_err = -1;
1798 if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH + mac_size)
1799 enc_err = -1;
1800 }
1801
1802 if (enc_err < 0) {
1803 /* decryption failed, silently discard message */
1804 rr->length = 0;
1805 RECORD_LAYER_reset_packet_length(&s->rlayer);
1806 return 0;
1807 }
1808
1809 /* r->length is now just compressed */
1810 if (s->expand != NULL) {
1811 if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH) {
1812 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_DTLS1_PROCESS_RECORD,
1813 SSL_R_COMPRESSED_LENGTH_TOO_LONG);
1814 return 0;
1815 }
1816 if (!ssl3_do_uncompress(s, rr)) {
1817 SSLfatal(s, SSL_AD_DECOMPRESSION_FAILURE,
1818 SSL_F_DTLS1_PROCESS_RECORD, SSL_R_BAD_DECOMPRESSION);
1819 return 0;
1820 }
1821 }
1822
1823 /* use current Max Fragment Length setting if applicable */
1824 if (s->session != NULL && USE_MAX_FRAGMENT_LENGTH_EXT(s->session))
1825 max_plain_length = GET_MAX_FRAGMENT_LENGTH(s->session);
1826
1827 /* send overflow if the plaintext is too long now it has passed MAC */
1828 if (rr->length > max_plain_length) {
1829 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_DTLS1_PROCESS_RECORD,
1830 SSL_R_DATA_LENGTH_TOO_LONG);
1831 return 0;
1832 }
1833
1834 rr->off = 0;
1835 /*-
1836 * So at this point the following is true
1837 * ssl->s3->rrec.type is the type of record
1838 * ssl->s3->rrec.length == number of bytes in record
1839 * ssl->s3->rrec.off == offset to first valid byte
1840 * ssl->s3->rrec.data == where to take bytes from, increment
1841 * after use :-).
1842 */
1843
1844 /* we have pulled in a full packet so zero things */
1845 RECORD_LAYER_reset_packet_length(&s->rlayer);
1846
1847 /* Mark receipt of record. */
1848 dtls1_record_bitmap_update(s, bitmap);
1849
1850 return 1;
1851 }
1852
1853 /*
1854 * Retrieve a buffered record that belongs to the current epoch, i.e. processed
1855 */
1856 #define dtls1_get_processed_record(s) \
1857 dtls1_retrieve_buffered_record((s), \
1858 &(DTLS_RECORD_LAYER_get_processed_rcds(&s->rlayer)))
1859
1860 /*-
1861 * Call this to get a new input record.
1862 * It will return <= 0 if more data is needed, normally due to an error
1863 * or non-blocking IO.
1864 * When it finishes, one packet has been decoded and can be found in
1865 * ssl->s3->rrec.type - is the type of record
1866 * ssl->s3->rrec.data, - data
1867 * ssl->s3->rrec.length, - number of bytes
1868 */
1869 /* used only by dtls1_read_bytes */
dtls1_get_record(SSL * s)1870 int dtls1_get_record(SSL *s)
1871 {
1872 int ssl_major, ssl_minor;
1873 int rret;
1874 size_t more, n;
1875 SSL3_RECORD *rr;
1876 unsigned char *p = NULL;
1877 unsigned short version;
1878 DTLS1_BITMAP *bitmap;
1879 unsigned int is_next_epoch;
1880
1881 rr = RECORD_LAYER_get_rrec(&s->rlayer);
1882
1883 again:
1884 /*
1885 * The epoch may have changed. If so, process all the pending records.
1886 * This is a non-blocking operation.
1887 */
1888 if (!dtls1_process_buffered_records(s)) {
1889 /* SSLfatal() already called */
1890 return -1;
1891 }
1892
1893 /* if we're renegotiating, then there may be buffered records */
1894 if (dtls1_get_processed_record(s))
1895 return 1;
1896
1897 /* get something from the wire */
1898
1899 /* check if we have the header */
1900 if ((RECORD_LAYER_get_rstate(&s->rlayer) != SSL_ST_READ_BODY) ||
1901 (RECORD_LAYER_get_packet_length(&s->rlayer) < DTLS1_RT_HEADER_LENGTH)) {
1902 rret = ssl3_read_n(s, DTLS1_RT_HEADER_LENGTH,
1903 SSL3_BUFFER_get_len(&s->rlayer.rbuf), 0, 1, &n);
1904 /* read timeout is handled by dtls1_read_bytes */
1905 if (rret <= 0) {
1906 /* SSLfatal() already called if appropriate */
1907 return rret; /* error or non-blocking */
1908 }
1909
1910 /* this packet contained a partial record, dump it */
1911 if (RECORD_LAYER_get_packet_length(&s->rlayer) !=
1912 DTLS1_RT_HEADER_LENGTH) {
1913 RECORD_LAYER_reset_packet_length(&s->rlayer);
1914 goto again;
1915 }
1916
1917 RECORD_LAYER_set_rstate(&s->rlayer, SSL_ST_READ_BODY);
1918
1919 p = RECORD_LAYER_get_packet(&s->rlayer);
1920
1921 if (s->msg_callback)
1922 s->msg_callback(0, 0, SSL3_RT_HEADER, p, DTLS1_RT_HEADER_LENGTH,
1923 s, s->msg_callback_arg);
1924
1925 /* Pull apart the header into the DTLS1_RECORD */
1926 rr->type = *(p++);
1927 ssl_major = *(p++);
1928 ssl_minor = *(p++);
1929 version = (ssl_major << 8) | ssl_minor;
1930
1931 /* sequence number is 64 bits, with top 2 bytes = epoch */
1932 n2s(p, rr->epoch);
1933
1934 memcpy(&(RECORD_LAYER_get_read_sequence(&s->rlayer)[2]), p, 6);
1935 p += 6;
1936
1937 n2s(p, rr->length);
1938 rr->read = 0;
1939
1940 /*
1941 * Lets check the version. We tolerate alerts that don't have the exact
1942 * version number (e.g. because of protocol version errors)
1943 */
1944 if (!s->first_packet && rr->type != SSL3_RT_ALERT) {
1945 if (version != s->version) {
1946 /* unexpected version, silently discard */
1947 rr->length = 0;
1948 rr->read = 1;
1949 RECORD_LAYER_reset_packet_length(&s->rlayer);
1950 goto again;
1951 }
1952 }
1953
1954 if ((version & 0xff00) != (s->version & 0xff00)) {
1955 /* wrong version, silently discard record */
1956 rr->length = 0;
1957 rr->read = 1;
1958 RECORD_LAYER_reset_packet_length(&s->rlayer);
1959 goto again;
1960 }
1961
1962 if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH) {
1963 /* record too long, silently discard it */
1964 rr->length = 0;
1965 rr->read = 1;
1966 RECORD_LAYER_reset_packet_length(&s->rlayer);
1967 goto again;
1968 }
1969
1970 /* If received packet overflows own-client Max Fragment Length setting */
1971 if (s->session != NULL && USE_MAX_FRAGMENT_LENGTH_EXT(s->session)
1972 && rr->length > GET_MAX_FRAGMENT_LENGTH(s->session) + SSL3_RT_MAX_ENCRYPTED_OVERHEAD) {
1973 /* record too long, silently discard it */
1974 rr->length = 0;
1975 rr->read = 1;
1976 RECORD_LAYER_reset_packet_length(&s->rlayer);
1977 goto again;
1978 }
1979
1980 /* now s->rlayer.rstate == SSL_ST_READ_BODY */
1981 }
1982
1983 /* s->rlayer.rstate == SSL_ST_READ_BODY, get and decode the data */
1984
1985 if (rr->length >
1986 RECORD_LAYER_get_packet_length(&s->rlayer) - DTLS1_RT_HEADER_LENGTH) {
1987 /* now s->rlayer.packet_length == DTLS1_RT_HEADER_LENGTH */
1988 more = rr->length;
1989 rret = ssl3_read_n(s, more, more, 1, 1, &n);
1990 /* this packet contained a partial record, dump it */
1991 if (rret <= 0 || n != more) {
1992 if (ossl_statem_in_error(s)) {
1993 /* ssl3_read_n() called SSLfatal() */
1994 return -1;
1995 }
1996 rr->length = 0;
1997 rr->read = 1;
1998 RECORD_LAYER_reset_packet_length(&s->rlayer);
1999 goto again;
2000 }
2001
2002 /*
2003 * now n == rr->length, and s->rlayer.packet_length ==
2004 * DTLS1_RT_HEADER_LENGTH + rr->length
2005 */
2006 }
2007 /* set state for later operations */
2008 RECORD_LAYER_set_rstate(&s->rlayer, SSL_ST_READ_HEADER);
2009
2010 /* match epochs. NULL means the packet is dropped on the floor */
2011 bitmap = dtls1_get_bitmap(s, rr, &is_next_epoch);
2012 if (bitmap == NULL) {
2013 rr->length = 0;
2014 RECORD_LAYER_reset_packet_length(&s->rlayer); /* dump this record */
2015 goto again; /* get another record */
2016 }
2017 #ifndef OPENSSL_NO_SCTP
2018 /* Only do replay check if no SCTP bio */
2019 if (!BIO_dgram_is_sctp(SSL_get_rbio(s))) {
2020 #endif
2021 /* Check whether this is a repeat, or aged record. */
2022 /*
2023 * TODO: Does it make sense to have replay protection in epoch 0 where
2024 * we have no integrity negotiated yet?
2025 */
2026 if (!dtls1_record_replay_check(s, bitmap)) {
2027 rr->length = 0;
2028 rr->read = 1;
2029 RECORD_LAYER_reset_packet_length(&s->rlayer); /* dump this record */
2030 goto again; /* get another record */
2031 }
2032 #ifndef OPENSSL_NO_SCTP
2033 }
2034 #endif
2035
2036 /* just read a 0 length packet */
2037 if (rr->length == 0) {
2038 rr->read = 1;
2039 goto again;
2040 }
2041
2042 /*
2043 * If this record is from the next epoch (either HM or ALERT), and a
2044 * handshake is currently in progress, buffer it since it cannot be
2045 * processed at this time.
2046 */
2047 if (is_next_epoch) {
2048 if ((SSL_in_init(s) || ossl_statem_get_in_handshake(s))) {
2049 if (dtls1_buffer_record (s,
2050 &(DTLS_RECORD_LAYER_get_unprocessed_rcds(&s->rlayer)),
2051 rr->seq_num) < 0) {
2052 /* SSLfatal() already called */
2053 return -1;
2054 }
2055 }
2056 rr->length = 0;
2057 rr->read = 1;
2058 RECORD_LAYER_reset_packet_length(&s->rlayer);
2059 goto again;
2060 }
2061
2062 if (!dtls1_process_record(s, bitmap)) {
2063 if (ossl_statem_in_error(s)) {
2064 /* dtls1_process_record() called SSLfatal */
2065 return -1;
2066 }
2067 rr->length = 0;
2068 rr->read = 1;
2069 RECORD_LAYER_reset_packet_length(&s->rlayer); /* dump this record */
2070 goto again; /* get another record */
2071 }
2072
2073 return 1;
2074
2075 }
2076
dtls_buffer_listen_record(SSL * s,size_t len,unsigned char * seq,size_t off)2077 int dtls_buffer_listen_record(SSL *s, size_t len, unsigned char *seq, size_t off)
2078 {
2079 SSL3_RECORD *rr;
2080
2081 rr = RECORD_LAYER_get_rrec(&s->rlayer);
2082 memset(rr, 0, sizeof(SSL3_RECORD));
2083
2084 rr->length = len;
2085 rr->type = SSL3_RT_HANDSHAKE;
2086 memcpy(rr->seq_num, seq, sizeof(rr->seq_num));
2087 rr->off = off;
2088
2089 s->rlayer.packet = RECORD_LAYER_get_rbuf(&s->rlayer)->buf;
2090 s->rlayer.packet_length = DTLS1_RT_HEADER_LENGTH + len;
2091 rr->data = s->rlayer.packet + DTLS1_RT_HEADER_LENGTH;
2092
2093 if (dtls1_buffer_record(s, &(s->rlayer.d->processed_rcds),
2094 SSL3_RECORD_get_seq_num(s->rlayer.rrec)) <= 0) {
2095 /* SSLfatal() already called */
2096 return 0;
2097 }
2098
2099 return 1;
2100 }
2101