1/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2 * All rights reserved.
3 *
4 * This package is an SSL implementation written
5 * by Eric Young (eay@cryptsoft.com).
6 * The implementation was written so as to conform with Netscapes SSL.
7 *
8 * This library is free for commercial and non-commercial use as long as
9 * the following conditions are aheared to. The following conditions
10 * apply to all code found in this distribution, be it the RC4, RSA,
11 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
12 * included with this distribution is covered by the same copyright terms
13 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14 *
15 * Copyright remains Eric Young's, and as such any Copyright notices in
16 * the code are not to be removed.
17 * If this package is used in a product, Eric Young should be given attribution
18 * as the author of the parts of the library used.
19 * This can be in the form of a textual message at program startup or
20 * in documentation (online or textual) provided with the package.
21 *
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
24 * are met:
25 * 1. Redistributions of source code must retain the copyright
26 * notice, this list of conditions and the following disclaimer.
27 * 2. Redistributions in binary form must reproduce the above copyright
28 * notice, this list of conditions and the following disclaimer in the
29 * documentation and/or other materials provided with the distribution.
30 * 3. All advertising materials mentioning features or use of this software
31 * must display the following acknowledgement:
32 * "This product includes cryptographic software written by
33 * Eric Young (eay@cryptsoft.com)"
34 * The word 'cryptographic' can be left out if the rouines from the library
35 * being used are not cryptographic related :-).
36 * 4. If you include any Windows specific code (or a derivative thereof) from
37 * the apps directory (application code) you must include an acknowledgement:
38 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39 *
40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50 * SUCH DAMAGE.
51 *
52 * The licence and distribution terms for any publically available version or
53 * derivative of this code cannot be changed. i.e. this code cannot simply be
54 * copied and put under another distribution licence
55 * [including the GNU Public Licence.]
56 */
57/* ====================================================================
58 * Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved.
59 *
60 * Redistribution and use in source and binary forms, with or without
61 * modification, are permitted provided that the following conditions
62 * are met:
63 *
64 * 1. Redistributions of source code must retain the above copyright
65 * notice, this list of conditions and the following disclaimer.
66 *
67 * 2. Redistributions in binary form must reproduce the above copyright
68 * notice, this list of conditions and the following disclaimer in
69 * the documentation and/or other materials provided with the
70 * distribution.
71 *
72 * 3. All advertising materials mentioning features or use of this
73 * software must display the following acknowledgment:
74 * "This product includes software developed by the OpenSSL Project
75 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
76 *
77 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
78 * endorse or promote products derived from this software without
79 * prior written permission. For written permission, please contact
80 * openssl-core@openssl.org.
81 *
82 * 5. Products derived from this software may not be called "OpenSSL"
83 * nor may "OpenSSL" appear in their names without prior written
84 * permission of the OpenSSL Project.
85 *
86 * 6. Redistributions of any form whatsoever must retain the following
87 * acknowledgment:
88 * "This product includes software developed by the OpenSSL Project
89 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
90 *
91 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
92 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
93 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
94 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
95 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
96 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
97 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
98 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
99 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
100 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
101 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
102 * OF THE POSSIBILITY OF SUCH DAMAGE.
103 * ====================================================================
104 *
105 * This product includes cryptographic software written by Eric Young
106 * (eay@cryptsoft.com). This product includes software written by Tim
107 * Hudson (tjh@cryptsoft.com). */
108
109#include <openssl/ssl.h>
110
111#include <assert.h>
112#include <string.h>
113
114#include <openssl/bytestring.h>
115#include <openssl/err.h>
116#include <openssl/mem.h>
117
118#include "internal.h"
119#include "../crypto/internal.h"
120
121
122BSSL_NAMESPACE_BEGIN
123
124// kMaxEmptyRecords is the number of consecutive, empty records that will be
125// processed. Without this limit an attacker could send empty records at a
126// faster rate than we can process and cause record processing to loop
127// forever.
128static const uint8_t kMaxEmptyRecords = 32;
129
130// kMaxEarlyDataSkipped is the maximum number of rejected early data bytes that
131// will be skipped. Without this limit an attacker could send records at a
132// faster rate than we can process and cause trial decryption to loop forever.
133// This value should be slightly above kMaxEarlyDataAccepted, which is measured
134// in plaintext.
135static const size_t kMaxEarlyDataSkipped = 16384;
136
137// kMaxWarningAlerts is the number of consecutive warning alerts that will be
138// processed.
139static const uint8_t kMaxWarningAlerts = 4;
140
141// ssl_needs_record_splitting returns one if |ssl|'s current outgoing cipher
142// state needs record-splitting and zero otherwise.
143static bool ssl_needs_record_splitting(const SSL *ssl) {
144#if !defined(BORINGSSL_UNSAFE_FUZZER_MODE)
145 return !ssl->s3->aead_write_ctx->is_null_cipher() &&
146 ssl->s3->aead_write_ctx->ProtocolVersion() < TLS1_1_VERSION &&
147 (ssl->mode & SSL_MODE_CBC_RECORD_SPLITTING) != 0 &&
148 SSL_CIPHER_is_block_cipher(ssl->s3->aead_write_ctx->cipher());
149#else
150 return false;
151#endif
152}
153
154bool ssl_record_sequence_update(uint8_t *seq, size_t seq_len) {
155 for (size_t i = seq_len - 1; i < seq_len; i--) {
156 ++seq[i];
157 if (seq[i] != 0) {
158 return true;
159 }
160 }
161 OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW);
162 return false;
163}
164
165size_t ssl_record_prefix_len(const SSL *ssl) {
166 size_t header_len;
167 if (SSL_is_dtls(ssl)) {
168 header_len = DTLS1_RT_HEADER_LENGTH;
169 } else {
170 header_len = SSL3_RT_HEADER_LENGTH;
171 }
172
173 return header_len + ssl->s3->aead_read_ctx->ExplicitNonceLen();
174}
175
176size_t ssl_seal_align_prefix_len(const SSL *ssl) {
177 if (SSL_is_dtls(ssl)) {
178 return DTLS1_RT_HEADER_LENGTH + ssl->s3->aead_write_ctx->ExplicitNonceLen();
179 }
180
181 size_t ret =
182 SSL3_RT_HEADER_LENGTH + ssl->s3->aead_write_ctx->ExplicitNonceLen();
183 if (ssl_needs_record_splitting(ssl)) {
184 ret += SSL3_RT_HEADER_LENGTH;
185 ret += ssl_cipher_get_record_split_len(ssl->s3->aead_write_ctx->cipher());
186 }
187 return ret;
188}
189
190static ssl_open_record_t skip_early_data(SSL *ssl, uint8_t *out_alert,
191 size_t consumed) {
192 ssl->s3->early_data_skipped += consumed;
193 if (ssl->s3->early_data_skipped < consumed) {
194 ssl->s3->early_data_skipped = kMaxEarlyDataSkipped + 1;
195 }
196
197 if (ssl->s3->early_data_skipped > kMaxEarlyDataSkipped) {
198 OPENSSL_PUT_ERROR(SSL, SSL_R_TOO_MUCH_SKIPPED_EARLY_DATA);
199 *out_alert = SSL_AD_UNEXPECTED_MESSAGE;
200 return ssl_open_record_error;
201 }
202
203 return ssl_open_record_discard;
204}
205
206ssl_open_record_t tls_open_record(SSL *ssl, uint8_t *out_type,
207 Span<uint8_t> *out, size_t *out_consumed,
208 uint8_t *out_alert, Span<uint8_t> in) {
209 *out_consumed = 0;
210 if (ssl->s3->read_shutdown == ssl_shutdown_close_notify) {
211 return ssl_open_record_close_notify;
212 }
213
214 // If there is an unprocessed handshake message or we are already buffering
215 // too much, stop before decrypting another handshake record.
216 if (!tls_can_accept_handshake_data(ssl, out_alert)) {
217 return ssl_open_record_error;
218 }
219
220 CBS cbs = CBS(in);
221
222 // Decode the record header.
223 uint8_t type;
224 uint16_t version, ciphertext_len;
225 if (!CBS_get_u8(&cbs, &type) ||
226 !CBS_get_u16(&cbs, &version) ||
227 !CBS_get_u16(&cbs, &ciphertext_len)) {
228 *out_consumed = SSL3_RT_HEADER_LENGTH;
229 return ssl_open_record_partial;
230 }
231
232 bool version_ok;
233 if (ssl->s3->aead_read_ctx->is_null_cipher()) {
234 // Only check the first byte. Enforcing beyond that can prevent decoding
235 // version negotiation failure alerts.
236 version_ok = (version >> 8) == SSL3_VERSION_MAJOR;
237 } else {
238 version_ok = version == ssl->s3->aead_read_ctx->RecordVersion();
239 }
240
241 if (!version_ok) {
242 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_VERSION_NUMBER);
243 *out_alert = SSL_AD_PROTOCOL_VERSION;
244 return ssl_open_record_error;
245 }
246
247 // Check the ciphertext length.
248 if (ciphertext_len > SSL3_RT_MAX_ENCRYPTED_LENGTH) {
249 OPENSSL_PUT_ERROR(SSL, SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
250 *out_alert = SSL_AD_RECORD_OVERFLOW;
251 return ssl_open_record_error;
252 }
253
254 // Extract the body.
255 CBS body;
256 if (!CBS_get_bytes(&cbs, &body, ciphertext_len)) {
257 *out_consumed = SSL3_RT_HEADER_LENGTH + (size_t)ciphertext_len;
258 return ssl_open_record_partial;
259 }
260
261 Span<const uint8_t> header = in.subspan(0, SSL3_RT_HEADER_LENGTH);
262 ssl_do_msg_callback(ssl, 0 /* read */, SSL3_RT_HEADER, header);
263
264 *out_consumed = in.size() - CBS_len(&cbs);
265
266 if (ssl->s3->have_version &&
267 ssl_protocol_version(ssl) >= TLS1_3_VERSION &&
268 SSL_in_init(ssl) &&
269 type == SSL3_RT_CHANGE_CIPHER_SPEC &&
270 ciphertext_len == 1 &&
271 CBS_data(&body)[0] == 1) {
272 ssl->s3->empty_record_count++;
273 if (ssl->s3->empty_record_count > kMaxEmptyRecords) {
274 OPENSSL_PUT_ERROR(SSL, SSL_R_TOO_MANY_EMPTY_FRAGMENTS);
275 *out_alert = SSL_AD_UNEXPECTED_MESSAGE;
276 return ssl_open_record_error;
277 }
278 return ssl_open_record_discard;
279 }
280
281 // Skip early data received when expecting a second ClientHello if we rejected
282 // 0RTT.
283 if (ssl->s3->skip_early_data &&
284 ssl->s3->aead_read_ctx->is_null_cipher() &&
285 type == SSL3_RT_APPLICATION_DATA) {
286 return skip_early_data(ssl, out_alert, *out_consumed);
287 }
288
289 // Decrypt the body in-place.
290 if (!ssl->s3->aead_read_ctx->Open(
291 out, type, version, ssl->s3->read_sequence, header,
292 MakeSpan(const_cast<uint8_t *>(CBS_data(&body)), CBS_len(&body)))) {
293 if (ssl->s3->skip_early_data && !ssl->s3->aead_read_ctx->is_null_cipher()) {
294 ERR_clear_error();
295 return skip_early_data(ssl, out_alert, *out_consumed);
296 }
297
298 OPENSSL_PUT_ERROR(SSL, SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
299 *out_alert = SSL_AD_BAD_RECORD_MAC;
300 return ssl_open_record_error;
301 }
302
303 ssl->s3->skip_early_data = false;
304
305 if (!ssl_record_sequence_update(ssl->s3->read_sequence, 8)) {
306 *out_alert = SSL_AD_INTERNAL_ERROR;
307 return ssl_open_record_error;
308 }
309
310 // TLS 1.3 hides the record type inside the encrypted data.
311 bool has_padding =
312 !ssl->s3->aead_read_ctx->is_null_cipher() &&
313 ssl->s3->aead_read_ctx->ProtocolVersion() >= TLS1_3_VERSION;
314
315 // If there is padding, the plaintext limit includes the padding, but includes
316 // extra room for the inner content type.
317 size_t plaintext_limit =
318 has_padding ? SSL3_RT_MAX_PLAIN_LENGTH + 1 : SSL3_RT_MAX_PLAIN_LENGTH;
319 if (out->size() > plaintext_limit) {
320 OPENSSL_PUT_ERROR(SSL, SSL_R_DATA_LENGTH_TOO_LONG);
321 *out_alert = SSL_AD_RECORD_OVERFLOW;
322 return ssl_open_record_error;
323 }
324
325 if (has_padding) {
326 // The outer record type is always application_data.
327 if (type != SSL3_RT_APPLICATION_DATA) {
328 OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_OUTER_RECORD_TYPE);
329 *out_alert = SSL_AD_DECODE_ERROR;
330 return ssl_open_record_error;
331 }
332
333 do {
334 if (out->empty()) {
335 OPENSSL_PUT_ERROR(SSL, SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
336 *out_alert = SSL_AD_DECRYPT_ERROR;
337 return ssl_open_record_error;
338 }
339 type = out->back();
340 *out = out->subspan(0, out->size() - 1);
341 } while (type == 0);
342 }
343
344 // Limit the number of consecutive empty records.
345 if (out->empty()) {
346 ssl->s3->empty_record_count++;
347 if (ssl->s3->empty_record_count > kMaxEmptyRecords) {
348 OPENSSL_PUT_ERROR(SSL, SSL_R_TOO_MANY_EMPTY_FRAGMENTS);
349 *out_alert = SSL_AD_UNEXPECTED_MESSAGE;
350 return ssl_open_record_error;
351 }
352 // Apart from the limit, empty records are returned up to the caller. This
353 // allows the caller to reject records of the wrong type.
354 } else {
355 ssl->s3->empty_record_count = 0;
356 }
357
358 if (type == SSL3_RT_ALERT) {
359 return ssl_process_alert(ssl, out_alert, *out);
360 }
361
362 // Handshake messages may not interleave with any other record type.
363 if (type != SSL3_RT_HANDSHAKE &&
364 tls_has_unprocessed_handshake_data(ssl)) {
365 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD);
366 *out_alert = SSL_AD_UNEXPECTED_MESSAGE;
367 return ssl_open_record_error;
368 }
369
370 ssl->s3->warning_alert_count = 0;
371
372 *out_type = type;
373 return ssl_open_record_success;
374}
375
376static bool do_seal_record(SSL *ssl, uint8_t *out_prefix, uint8_t *out,
377 uint8_t *out_suffix, uint8_t type, const uint8_t *in,
378 const size_t in_len) {
379 SSLAEADContext *aead = ssl->s3->aead_write_ctx.get();
380 uint8_t *extra_in = NULL;
381 size_t extra_in_len = 0;
382 if (!aead->is_null_cipher() &&
383 aead->ProtocolVersion() >= TLS1_3_VERSION) {
384 // TLS 1.3 hides the actual record type inside the encrypted data.
385 extra_in = &type;
386 extra_in_len = 1;
387 }
388
389 size_t suffix_len, ciphertext_len;
390 if (!aead->SuffixLen(&suffix_len, in_len, extra_in_len) ||
391 !aead->CiphertextLen(&ciphertext_len, in_len, extra_in_len)) {
392 OPENSSL_PUT_ERROR(SSL, SSL_R_RECORD_TOO_LARGE);
393 return false;
394 }
395
396 assert(in == out || !buffers_alias(in, in_len, out, in_len));
397 assert(!buffers_alias(in, in_len, out_prefix, ssl_record_prefix_len(ssl)));
398 assert(!buffers_alias(in, in_len, out_suffix, suffix_len));
399
400 if (extra_in_len) {
401 out_prefix[0] = SSL3_RT_APPLICATION_DATA;
402 } else {
403 out_prefix[0] = type;
404 }
405
406 uint16_t record_version = aead->RecordVersion();
407
408 out_prefix[1] = record_version >> 8;
409 out_prefix[2] = record_version & 0xff;
410 out_prefix[3] = ciphertext_len >> 8;
411 out_prefix[4] = ciphertext_len & 0xff;
412 Span<const uint8_t> header = MakeSpan(out_prefix, SSL3_RT_HEADER_LENGTH);
413
414 if (!aead->SealScatter(out_prefix + SSL3_RT_HEADER_LENGTH, out, out_suffix,
415 out_prefix[0], record_version, ssl->s3->write_sequence,
416 header, in, in_len, extra_in, extra_in_len) ||
417 !ssl_record_sequence_update(ssl->s3->write_sequence, 8)) {
418 return false;
419 }
420
421 ssl_do_msg_callback(ssl, 1 /* write */, SSL3_RT_HEADER, header);
422 return true;
423}
424
425static size_t tls_seal_scatter_prefix_len(const SSL *ssl, uint8_t type,
426 size_t in_len) {
427 size_t ret = SSL3_RT_HEADER_LENGTH;
428 if (type == SSL3_RT_APPLICATION_DATA && in_len > 1 &&
429 ssl_needs_record_splitting(ssl)) {
430 // In the case of record splitting, the 1-byte record (of the 1/n-1 split)
431 // will be placed in the prefix, as will four of the five bytes of the
432 // record header for the main record. The final byte will replace the first
433 // byte of the plaintext that was used in the small record.
434 ret += ssl_cipher_get_record_split_len(ssl->s3->aead_write_ctx->cipher());
435 ret += SSL3_RT_HEADER_LENGTH - 1;
436 } else {
437 ret += ssl->s3->aead_write_ctx->ExplicitNonceLen();
438 }
439 return ret;
440}
441
442static bool tls_seal_scatter_suffix_len(const SSL *ssl, size_t *out_suffix_len,
443 uint8_t type, size_t in_len) {
444 size_t extra_in_len = 0;
445 if (!ssl->s3->aead_write_ctx->is_null_cipher() &&
446 ssl->s3->aead_write_ctx->ProtocolVersion() >= TLS1_3_VERSION) {
447 // TLS 1.3 adds an extra byte for encrypted record type.
448 extra_in_len = 1;
449 }
450 if (type == SSL3_RT_APPLICATION_DATA && // clang-format off
451 in_len > 1 &&
452 ssl_needs_record_splitting(ssl)) {
453 // With record splitting enabled, the first byte gets sealed into a separate
454 // record which is written into the prefix.
455 in_len -= 1;
456 }
457 return ssl->s3->aead_write_ctx->SuffixLen(out_suffix_len, in_len, extra_in_len);
458}
459
460// tls_seal_scatter_record seals a new record of type |type| and body |in| and
461// splits it between |out_prefix|, |out|, and |out_suffix|. Exactly
462// |tls_seal_scatter_prefix_len| bytes are written to |out_prefix|, |in_len|
463// bytes to |out|, and |tls_seal_scatter_suffix_len| bytes to |out_suffix|. It
464// returns one on success and zero on error. If enabled,
465// |tls_seal_scatter_record| implements TLS 1.0 CBC 1/n-1 record splitting and
466// may write two records concatenated.
467static bool tls_seal_scatter_record(SSL *ssl, uint8_t *out_prefix, uint8_t *out,
468 uint8_t *out_suffix, uint8_t type,
469 const uint8_t *in, size_t in_len) {
470 if (type == SSL3_RT_APPLICATION_DATA && in_len > 1 &&
471 ssl_needs_record_splitting(ssl)) {
472 assert(ssl->s3->aead_write_ctx->ExplicitNonceLen() == 0);
473 const size_t prefix_len = SSL3_RT_HEADER_LENGTH;
474
475 // Write the 1-byte fragment into |out_prefix|.
476 uint8_t *split_body = out_prefix + prefix_len;
477 uint8_t *split_suffix = split_body + 1;
478
479 if (!do_seal_record(ssl, out_prefix, split_body, split_suffix, type, in,
480 1)) {
481 return false;
482 }
483
484 size_t split_record_suffix_len;
485 if (!ssl->s3->aead_write_ctx->SuffixLen(&split_record_suffix_len, 1, 0)) {
486 assert(false);
487 return false;
488 }
489 const size_t split_record_len = prefix_len + 1 + split_record_suffix_len;
490 assert(SSL3_RT_HEADER_LENGTH + ssl_cipher_get_record_split_len(
491 ssl->s3->aead_write_ctx->cipher()) ==
492 split_record_len);
493
494 // Write the n-1-byte fragment. The header gets split between |out_prefix|
495 // (header[:-1]) and |out| (header[-1:]).
496 uint8_t tmp_prefix[SSL3_RT_HEADER_LENGTH];
497 if (!do_seal_record(ssl, tmp_prefix, out + 1, out_suffix, type, in + 1,
498 in_len - 1)) {
499 return false;
500 }
501 assert(tls_seal_scatter_prefix_len(ssl, type, in_len) ==
502 split_record_len + SSL3_RT_HEADER_LENGTH - 1);
503 OPENSSL_memcpy(out_prefix + split_record_len, tmp_prefix,
504 SSL3_RT_HEADER_LENGTH - 1);
505 OPENSSL_memcpy(out, tmp_prefix + SSL3_RT_HEADER_LENGTH - 1, 1);
506 return true;
507 }
508
509 return do_seal_record(ssl, out_prefix, out, out_suffix, type, in, in_len);
510}
511
512bool tls_seal_record(SSL *ssl, uint8_t *out, size_t *out_len,
513 size_t max_out_len, uint8_t type, const uint8_t *in,
514 size_t in_len) {
515 if (buffers_alias(in, in_len, out, max_out_len)) {
516 OPENSSL_PUT_ERROR(SSL, SSL_R_OUTPUT_ALIASES_INPUT);
517 return false;
518 }
519
520 const size_t prefix_len = tls_seal_scatter_prefix_len(ssl, type, in_len);
521 size_t suffix_len;
522 if (!tls_seal_scatter_suffix_len(ssl, &suffix_len, type, in_len)) {
523 return false;
524 }
525 if (in_len + prefix_len < in_len ||
526 prefix_len + in_len + suffix_len < prefix_len + in_len) {
527 OPENSSL_PUT_ERROR(SSL, SSL_R_RECORD_TOO_LARGE);
528 return false;
529 }
530 if (max_out_len < in_len + prefix_len + suffix_len) {
531 OPENSSL_PUT_ERROR(SSL, SSL_R_BUFFER_TOO_SMALL);
532 return false;
533 }
534
535 uint8_t *prefix = out;
536 uint8_t *body = out + prefix_len;
537 uint8_t *suffix = body + in_len;
538 if (!tls_seal_scatter_record(ssl, prefix, body, suffix, type, in, in_len)) {
539 return false;
540 }
541
542 *out_len = prefix_len + in_len + suffix_len;
543 return true;
544}
545
546enum ssl_open_record_t ssl_process_alert(SSL *ssl, uint8_t *out_alert,
547 Span<const uint8_t> in) {
548 // Alerts records may not contain fragmented or multiple alerts.
549 if (in.size() != 2) {
550 *out_alert = SSL_AD_DECODE_ERROR;
551 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_ALERT);
552 return ssl_open_record_error;
553 }
554
555 ssl_do_msg_callback(ssl, 0 /* read */, SSL3_RT_ALERT, in);
556
557 const uint8_t alert_level = in[0];
558 const uint8_t alert_descr = in[1];
559
560 uint16_t alert = (alert_level << 8) | alert_descr;
561 ssl_do_info_callback(ssl, SSL_CB_READ_ALERT, alert);
562
563 if (alert_level == SSL3_AL_WARNING) {
564 if (alert_descr == SSL_AD_CLOSE_NOTIFY) {
565 ssl->s3->read_shutdown = ssl_shutdown_close_notify;
566 return ssl_open_record_close_notify;
567 }
568
569 // Warning alerts do not exist in TLS 1.3.
570 if (ssl->s3->have_version &&
571 ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
572 *out_alert = SSL_AD_DECODE_ERROR;
573 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_ALERT);
574 return ssl_open_record_error;
575 }
576
577 ssl->s3->warning_alert_count++;
578 if (ssl->s3->warning_alert_count > kMaxWarningAlerts) {
579 *out_alert = SSL_AD_UNEXPECTED_MESSAGE;
580 OPENSSL_PUT_ERROR(SSL, SSL_R_TOO_MANY_WARNING_ALERTS);
581 return ssl_open_record_error;
582 }
583 return ssl_open_record_discard;
584 }
585
586 if (alert_level == SSL3_AL_FATAL) {
587 OPENSSL_PUT_ERROR(SSL, SSL_AD_REASON_OFFSET + alert_descr);
588 ERR_add_error_dataf("SSL alert number %d", alert_descr);
589 *out_alert = 0; // No alert to send back to the peer.
590 return ssl_open_record_error;
591 }
592
593 *out_alert = SSL_AD_ILLEGAL_PARAMETER;
594 OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_ALERT_TYPE);
595 return ssl_open_record_error;
596}
597
598OpenRecordResult OpenRecord(SSL *ssl, Span<uint8_t> *out,
599 size_t *out_record_len, uint8_t *out_alert,
600 const Span<uint8_t> in) {
601 // This API is a work in progress and currently only works for TLS 1.2 servers
602 // and below.
603 if (SSL_in_init(ssl) ||
604 SSL_is_dtls(ssl) ||
605 ssl_protocol_version(ssl) > TLS1_2_VERSION) {
606 assert(false);
607 *out_alert = SSL_AD_INTERNAL_ERROR;
608 return OpenRecordResult::kError;
609 }
610
611 Span<uint8_t> plaintext;
612 uint8_t type = 0;
613 const ssl_open_record_t result = tls_open_record(
614 ssl, &type, &plaintext, out_record_len, out_alert, in);
615
616 switch (result) {
617 case ssl_open_record_success:
618 if (type != SSL3_RT_APPLICATION_DATA && type != SSL3_RT_ALERT) {
619 *out_alert = SSL_AD_UNEXPECTED_MESSAGE;
620 return OpenRecordResult::kError;
621 }
622 *out = plaintext;
623 return OpenRecordResult::kOK;
624 case ssl_open_record_discard:
625 return OpenRecordResult::kDiscard;
626 case ssl_open_record_partial:
627 return OpenRecordResult::kIncompleteRecord;
628 case ssl_open_record_close_notify:
629 return OpenRecordResult::kAlertCloseNotify;
630 case ssl_open_record_error:
631 return OpenRecordResult::kError;
632 }
633 assert(false);
634 return OpenRecordResult::kError;
635}
636
637size_t SealRecordPrefixLen(const SSL *ssl, const size_t record_len) {
638 return tls_seal_scatter_prefix_len(ssl, SSL3_RT_APPLICATION_DATA, record_len);
639}
640
641size_t SealRecordSuffixLen(const SSL *ssl, const size_t plaintext_len) {
642 assert(plaintext_len <= SSL3_RT_MAX_PLAIN_LENGTH);
643 size_t suffix_len;
644 if (!tls_seal_scatter_suffix_len(ssl, &suffix_len, SSL3_RT_APPLICATION_DATA,
645 plaintext_len)) {
646 assert(false);
647 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
648 return 0;
649 }
650 assert(suffix_len <= SSL3_RT_MAX_ENCRYPTED_OVERHEAD);
651 return suffix_len;
652}
653
654bool SealRecord(SSL *ssl, const Span<uint8_t> out_prefix,
655 const Span<uint8_t> out, Span<uint8_t> out_suffix,
656 const Span<const uint8_t> in) {
657 // This API is a work in progress and currently only works for TLS 1.2 servers
658 // and below.
659 if (SSL_in_init(ssl) ||
660 SSL_is_dtls(ssl) ||
661 ssl_protocol_version(ssl) > TLS1_2_VERSION) {
662 assert(false);
663 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
664 return false;
665 }
666
667 if (out_prefix.size() != SealRecordPrefixLen(ssl, in.size()) ||
668 out.size() != in.size() ||
669 out_suffix.size() != SealRecordSuffixLen(ssl, in.size())) {
670 OPENSSL_PUT_ERROR(SSL, SSL_R_BUFFER_TOO_SMALL);
671 return false;
672 }
673 return tls_seal_scatter_record(ssl, out_prefix.data(), out.data(),
674 out_suffix.data(), SSL3_RT_APPLICATION_DATA,
675 in.data(), in.size());
676}
677
678BSSL_NAMESPACE_END
679
680using namespace bssl;
681
682size_t SSL_max_seal_overhead(const SSL *ssl) {
683 if (SSL_is_dtls(ssl)) {
684 return dtls_max_seal_overhead(ssl, dtls1_use_current_epoch);
685 }
686
687 size_t ret = SSL3_RT_HEADER_LENGTH;
688 ret += ssl->s3->aead_write_ctx->MaxOverhead();
689 // TLS 1.3 needs an extra byte for the encrypted record type.
690 if (!ssl->s3->aead_write_ctx->is_null_cipher() &&
691 ssl->s3->aead_write_ctx->ProtocolVersion() >= TLS1_3_VERSION) {
692 ret += 1;
693 }
694 if (ssl_needs_record_splitting(ssl)) {
695 ret *= 2;
696 }
697 return ret;
698}
699