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 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
110 * ECC cipher suite support in OpenSSL originally developed by
111 * SUN MICROSYSTEMS, INC., and contributed to the OpenSSL project. */
112
113#include <openssl/ssl.h>
114
115#include <assert.h>
116#include <limits.h>
117#include <string.h>
118
119#include <tuple>
120
121#include <openssl/buf.h>
122#include <openssl/bytestring.h>
123#include <openssl/err.h>
124#include <openssl/evp.h>
125#include <openssl/mem.h>
126#include <openssl/md5.h>
127#include <openssl/nid.h>
128#include <openssl/rand.h>
129#include <openssl/sha.h>
130
131#include "../crypto/internal.h"
132#include "internal.h"
133
134
135BSSL_NAMESPACE_BEGIN
136
137static bool add_record_to_flight(SSL *ssl, uint8_t type,
138 Span<const uint8_t> in) {
139 // The caller should have flushed |pending_hs_data| first.
140 assert(!ssl->s3->pending_hs_data);
141 // We'll never add a flight while in the process of writing it out.
142 assert(ssl->s3->pending_flight_offset == 0);
143
144 if (ssl->s3->pending_flight == nullptr) {
145 ssl->s3->pending_flight.reset(BUF_MEM_new());
146 if (ssl->s3->pending_flight == nullptr) {
147 return false;
148 }
149 }
150
151 size_t max_out = in.size() + SSL_max_seal_overhead(ssl);
152 size_t new_cap = ssl->s3->pending_flight->length + max_out;
153 if (max_out < in.size() || new_cap < max_out) {
154 OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW);
155 return false;
156 }
157
158 size_t len;
159 if (!BUF_MEM_reserve(ssl->s3->pending_flight.get(), new_cap) ||
160 !tls_seal_record(ssl,
161 (uint8_t *)ssl->s3->pending_flight->data +
162 ssl->s3->pending_flight->length,
163 &len, max_out, type, in.data(), in.size())) {
164 return false;
165 }
166
167 ssl->s3->pending_flight->length += len;
168 return true;
169}
170
171bool ssl3_init_message(SSL *ssl, CBB *cbb, CBB *body, uint8_t type) {
172 // Pick a modest size hint to save most of the |realloc| calls.
173 if (!CBB_init(cbb, 64) ||
174 !CBB_add_u8(cbb, type) ||
175 !CBB_add_u24_length_prefixed(cbb, body)) {
176 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
177 CBB_cleanup(cbb);
178 return false;
179 }
180
181 return true;
182}
183
184bool ssl3_finish_message(SSL *ssl, CBB *cbb, Array<uint8_t> *out_msg) {
185 return CBBFinishArray(cbb, out_msg);
186}
187
188bool ssl3_add_message(SSL *ssl, Array<uint8_t> msg) {
189 // Pack handshake data into the minimal number of records. This avoids
190 // unnecessary encryption overhead, notably in TLS 1.3 where we send several
191 // encrypted messages in a row. For now, we do not do this for the null
192 // cipher. The benefit is smaller and there is a risk of breaking buggy
193 // implementations.
194 //
195 // TODO(davidben): See if we can do this uniformly.
196 Span<const uint8_t> rest = msg;
197 if (ssl->quic_method == nullptr &&
198 ssl->s3->aead_write_ctx->is_null_cipher()) {
199 while (!rest.empty()) {
200 Span<const uint8_t> chunk = rest.subspan(0, ssl->max_send_fragment);
201 rest = rest.subspan(chunk.size());
202
203 if (!add_record_to_flight(ssl, SSL3_RT_HANDSHAKE, chunk)) {
204 return false;
205 }
206 }
207 } else {
208 while (!rest.empty()) {
209 // Flush if |pending_hs_data| is full.
210 if (ssl->s3->pending_hs_data &&
211 ssl->s3->pending_hs_data->length >= ssl->max_send_fragment &&
212 !tls_flush_pending_hs_data(ssl)) {
213 return false;
214 }
215
216 size_t pending_len =
217 ssl->s3->pending_hs_data ? ssl->s3->pending_hs_data->length : 0;
218 Span<const uint8_t> chunk =
219 rest.subspan(0, ssl->max_send_fragment - pending_len);
220 assert(!chunk.empty());
221 rest = rest.subspan(chunk.size());
222
223 if (!ssl->s3->pending_hs_data) {
224 ssl->s3->pending_hs_data.reset(BUF_MEM_new());
225 }
226 if (!ssl->s3->pending_hs_data ||
227 !BUF_MEM_append(ssl->s3->pending_hs_data.get(), chunk.data(),
228 chunk.size())) {
229 return false;
230 }
231 }
232 }
233
234 ssl_do_msg_callback(ssl, 1 /* write */, SSL3_RT_HANDSHAKE, msg);
235 // TODO(svaldez): Move this up a layer to fix abstraction for SSLTranscript on
236 // hs.
237 if (ssl->s3->hs != NULL &&
238 !ssl->s3->hs->transcript.Update(msg)) {
239 return false;
240 }
241 return true;
242}
243
244bool tls_flush_pending_hs_data(SSL *ssl) {
245 if (!ssl->s3->pending_hs_data || ssl->s3->pending_hs_data->length == 0) {
246 return true;
247 }
248
249 UniquePtr<BUF_MEM> pending_hs_data = std::move(ssl->s3->pending_hs_data);
250 auto data =
251 MakeConstSpan(reinterpret_cast<const uint8_t *>(pending_hs_data->data),
252 pending_hs_data->length);
253 if (ssl->quic_method) {
254 if (!ssl->quic_method->add_handshake_data(ssl, ssl->s3->write_level,
255 data.data(), data.size())) {
256 OPENSSL_PUT_ERROR(SSL, SSL_R_QUIC_INTERNAL_ERROR);
257 return false;
258 }
259 return true;
260 }
261
262 return add_record_to_flight(ssl, SSL3_RT_HANDSHAKE, data);
263}
264
265bool ssl3_add_change_cipher_spec(SSL *ssl) {
266 static const uint8_t kChangeCipherSpec[1] = {SSL3_MT_CCS};
267
268 if (!tls_flush_pending_hs_data(ssl)) {
269 return false;
270 }
271
272 if (!ssl->quic_method &&
273 !add_record_to_flight(ssl, SSL3_RT_CHANGE_CIPHER_SPEC,
274 kChangeCipherSpec)) {
275 return false;
276 }
277
278 ssl_do_msg_callback(ssl, 1 /* write */, SSL3_RT_CHANGE_CIPHER_SPEC,
279 kChangeCipherSpec);
280 return true;
281}
282
283int ssl3_flush_flight(SSL *ssl) {
284 if (!tls_flush_pending_hs_data(ssl)) {
285 return -1;
286 }
287
288 if (ssl->quic_method) {
289 if (ssl->s3->write_shutdown != ssl_shutdown_none) {
290 OPENSSL_PUT_ERROR(SSL, SSL_R_PROTOCOL_IS_SHUTDOWN);
291 return -1;
292 }
293
294 if (!ssl->quic_method->flush_flight(ssl)) {
295 OPENSSL_PUT_ERROR(SSL, SSL_R_QUIC_INTERNAL_ERROR);
296 return -1;
297 }
298 }
299
300 if (ssl->s3->pending_flight == nullptr) {
301 return 1;
302 }
303
304 if (ssl->s3->write_shutdown != ssl_shutdown_none) {
305 OPENSSL_PUT_ERROR(SSL, SSL_R_PROTOCOL_IS_SHUTDOWN);
306 return -1;
307 }
308
309 static_assert(INT_MAX <= 0xffffffff, "int is larger than 32 bits");
310 if (ssl->s3->pending_flight->length > INT_MAX) {
311 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
312 return -1;
313 }
314
315 // If there is pending data in the write buffer, it must be flushed out before
316 // any new data in pending_flight.
317 if (!ssl->s3->write_buffer.empty()) {
318 int ret = ssl_write_buffer_flush(ssl);
319 if (ret <= 0) {
320 ssl->s3->rwstate = SSL_WRITING;
321 return ret;
322 }
323 }
324
325 // Write the pending flight.
326 while (ssl->s3->pending_flight_offset < ssl->s3->pending_flight->length) {
327 int ret = BIO_write(
328 ssl->wbio.get(),
329 ssl->s3->pending_flight->data + ssl->s3->pending_flight_offset,
330 ssl->s3->pending_flight->length - ssl->s3->pending_flight_offset);
331 if (ret <= 0) {
332 ssl->s3->rwstate = SSL_WRITING;
333 return ret;
334 }
335
336 ssl->s3->pending_flight_offset += ret;
337 }
338
339 if (BIO_flush(ssl->wbio.get()) <= 0) {
340 ssl->s3->rwstate = SSL_WRITING;
341 return -1;
342 }
343
344 ssl->s3->pending_flight.reset();
345 ssl->s3->pending_flight_offset = 0;
346 return 1;
347}
348
349static ssl_open_record_t read_v2_client_hello(SSL *ssl, size_t *out_consumed,
350 Span<const uint8_t> in) {
351 *out_consumed = 0;
352 assert(in.size() >= SSL3_RT_HEADER_LENGTH);
353 // Determine the length of the V2ClientHello.
354 size_t msg_length = ((in[0] & 0x7f) << 8) | in[1];
355 if (msg_length > (1024 * 4)) {
356 OPENSSL_PUT_ERROR(SSL, SSL_R_RECORD_TOO_LARGE);
357 return ssl_open_record_error;
358 }
359 if (msg_length < SSL3_RT_HEADER_LENGTH - 2) {
360 // Reject lengths that are too short early. We have already read
361 // |SSL3_RT_HEADER_LENGTH| bytes, so we should not attempt to process an
362 // (invalid) V2ClientHello which would be shorter than that.
363 OPENSSL_PUT_ERROR(SSL, SSL_R_RECORD_LENGTH_MISMATCH);
364 return ssl_open_record_error;
365 }
366
367 // Ask for the remainder of the V2ClientHello.
368 if (in.size() < 2 + msg_length) {
369 *out_consumed = 2 + msg_length;
370 return ssl_open_record_partial;
371 }
372
373 CBS v2_client_hello = CBS(ssl->s3->read_buffer.span().subspan(2, msg_length));
374 // The V2ClientHello without the length is incorporated into the handshake
375 // hash. This is only ever called at the start of the handshake, so hs is
376 // guaranteed to be non-NULL.
377 if (!ssl->s3->hs->transcript.Update(v2_client_hello)) {
378 return ssl_open_record_error;
379 }
380
381 ssl_do_msg_callback(ssl, 0 /* read */, 0 /* V2ClientHello */,
382 v2_client_hello);
383
384 uint8_t msg_type;
385 uint16_t version, cipher_spec_length, session_id_length, challenge_length;
386 CBS cipher_specs, session_id, challenge;
387 if (!CBS_get_u8(&v2_client_hello, &msg_type) ||
388 !CBS_get_u16(&v2_client_hello, &version) ||
389 !CBS_get_u16(&v2_client_hello, &cipher_spec_length) ||
390 !CBS_get_u16(&v2_client_hello, &session_id_length) ||
391 !CBS_get_u16(&v2_client_hello, &challenge_length) ||
392 !CBS_get_bytes(&v2_client_hello, &cipher_specs, cipher_spec_length) ||
393 !CBS_get_bytes(&v2_client_hello, &session_id, session_id_length) ||
394 !CBS_get_bytes(&v2_client_hello, &challenge, challenge_length) ||
395 CBS_len(&v2_client_hello) != 0) {
396 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
397 return ssl_open_record_error;
398 }
399
400 // msg_type has already been checked.
401 assert(msg_type == SSL2_MT_CLIENT_HELLO);
402
403 // The client_random is the V2ClientHello challenge. Truncate or left-pad with
404 // zeros as needed.
405 size_t rand_len = CBS_len(&challenge);
406 if (rand_len > SSL3_RANDOM_SIZE) {
407 rand_len = SSL3_RANDOM_SIZE;
408 }
409 uint8_t random[SSL3_RANDOM_SIZE];
410 OPENSSL_memset(random, 0, SSL3_RANDOM_SIZE);
411 OPENSSL_memcpy(random + (SSL3_RANDOM_SIZE - rand_len), CBS_data(&challenge),
412 rand_len);
413
414 // Write out an equivalent TLS ClientHello directly to the handshake buffer.
415 size_t max_v3_client_hello = SSL3_HM_HEADER_LENGTH + 2 /* version */ +
416 SSL3_RANDOM_SIZE + 1 /* session ID length */ +
417 2 /* cipher list length */ +
418 CBS_len(&cipher_specs) / 3 * 2 +
419 1 /* compression length */ + 1 /* compression */;
420 ScopedCBB client_hello;
421 CBB hello_body, cipher_suites;
422 if (!ssl->s3->hs_buf) {
423 ssl->s3->hs_buf.reset(BUF_MEM_new());
424 }
425 if (!ssl->s3->hs_buf ||
426 !BUF_MEM_reserve(ssl->s3->hs_buf.get(), max_v3_client_hello) ||
427 !CBB_init_fixed(client_hello.get(), (uint8_t *)ssl->s3->hs_buf->data,
428 ssl->s3->hs_buf->max) ||
429 !CBB_add_u8(client_hello.get(), SSL3_MT_CLIENT_HELLO) ||
430 !CBB_add_u24_length_prefixed(client_hello.get(), &hello_body) ||
431 !CBB_add_u16(&hello_body, version) ||
432 !CBB_add_bytes(&hello_body, random, SSL3_RANDOM_SIZE) ||
433 // No session id.
434 !CBB_add_u8(&hello_body, 0) ||
435 !CBB_add_u16_length_prefixed(&hello_body, &cipher_suites)) {
436 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
437 return ssl_open_record_error;
438 }
439
440 // Copy the cipher suites.
441 while (CBS_len(&cipher_specs) > 0) {
442 uint32_t cipher_spec;
443 if (!CBS_get_u24(&cipher_specs, &cipher_spec)) {
444 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
445 return ssl_open_record_error;
446 }
447
448 // Skip SSLv2 ciphers.
449 if ((cipher_spec & 0xff0000) != 0) {
450 continue;
451 }
452 if (!CBB_add_u16(&cipher_suites, cipher_spec)) {
453 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
454 return ssl_open_record_error;
455 }
456 }
457
458 // Add the null compression scheme and finish.
459 if (!CBB_add_u8(&hello_body, 1) ||
460 !CBB_add_u8(&hello_body, 0) ||
461 !CBB_finish(client_hello.get(), NULL, &ssl->s3->hs_buf->length)) {
462 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
463 return ssl_open_record_error;
464 }
465
466 *out_consumed = 2 + msg_length;
467 ssl->s3->is_v2_hello = true;
468 return ssl_open_record_success;
469}
470
471static bool parse_message(const SSL *ssl, SSLMessage *out,
472 size_t *out_bytes_needed) {
473 if (!ssl->s3->hs_buf) {
474 *out_bytes_needed = 4;
475 return false;
476 }
477
478 CBS cbs;
479 uint32_t len;
480 CBS_init(&cbs, reinterpret_cast<const uint8_t *>(ssl->s3->hs_buf->data),
481 ssl->s3->hs_buf->length);
482 if (!CBS_get_u8(&cbs, &out->type) ||
483 !CBS_get_u24(&cbs, &len)) {
484 *out_bytes_needed = 4;
485 return false;
486 }
487
488 if (!CBS_get_bytes(&cbs, &out->body, len)) {
489 *out_bytes_needed = 4 + len;
490 return false;
491 }
492
493 CBS_init(&out->raw, reinterpret_cast<const uint8_t *>(ssl->s3->hs_buf->data),
494 4 + len);
495 out->is_v2_hello = ssl->s3->is_v2_hello;
496 return true;
497}
498
499bool ssl3_get_message(const SSL *ssl, SSLMessage *out) {
500 size_t unused;
501 if (!parse_message(ssl, out, &unused)) {
502 return false;
503 }
504 if (!ssl->s3->has_message) {
505 if (!out->is_v2_hello) {
506 ssl_do_msg_callback(ssl, 0 /* read */, SSL3_RT_HANDSHAKE, out->raw);
507 }
508 ssl->s3->has_message = true;
509 }
510 return true;
511}
512
513bool tls_can_accept_handshake_data(const SSL *ssl, uint8_t *out_alert) {
514 // If there is a complete message, the caller must have consumed it first.
515 SSLMessage msg;
516 size_t bytes_needed;
517 if (parse_message(ssl, &msg, &bytes_needed)) {
518 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
519 *out_alert = SSL_AD_INTERNAL_ERROR;
520 return false;
521 }
522
523 // Enforce the limit so the peer cannot force us to buffer 16MB.
524 if (bytes_needed > 4 + ssl_max_handshake_message_len(ssl)) {
525 OPENSSL_PUT_ERROR(SSL, SSL_R_EXCESSIVE_MESSAGE_SIZE);
526 *out_alert = SSL_AD_ILLEGAL_PARAMETER;
527 return false;
528 }
529
530 return true;
531}
532
533bool tls_has_unprocessed_handshake_data(const SSL *ssl) {
534 size_t msg_len = 0;
535 if (ssl->s3->has_message) {
536 SSLMessage msg;
537 size_t unused;
538 if (parse_message(ssl, &msg, &unused)) {
539 msg_len = CBS_len(&msg.raw);
540 }
541 }
542
543 return ssl->s3->hs_buf && ssl->s3->hs_buf->length > msg_len;
544}
545
546bool tls_append_handshake_data(SSL *ssl, Span<const uint8_t> data) {
547 // Re-create the handshake buffer if needed.
548 if (!ssl->s3->hs_buf) {
549 ssl->s3->hs_buf.reset(BUF_MEM_new());
550 }
551 return ssl->s3->hs_buf &&
552 BUF_MEM_append(ssl->s3->hs_buf.get(), data.data(), data.size());
553}
554
555ssl_open_record_t ssl3_open_handshake(SSL *ssl, size_t *out_consumed,
556 uint8_t *out_alert, Span<uint8_t> in) {
557 *out_consumed = 0;
558 // Bypass the record layer for the first message to handle V2ClientHello.
559 if (ssl->server && !ssl->s3->v2_hello_done) {
560 // Ask for the first 5 bytes, the size of the TLS record header. This is
561 // sufficient to detect a V2ClientHello and ensures that we never read
562 // beyond the first record.
563 if (in.size() < SSL3_RT_HEADER_LENGTH) {
564 *out_consumed = SSL3_RT_HEADER_LENGTH;
565 return ssl_open_record_partial;
566 }
567
568 // Some dedicated error codes for protocol mixups should the application
569 // wish to interpret them differently. (These do not overlap with
570 // ClientHello or V2ClientHello.)
571 const char *str = reinterpret_cast<const char*>(in.data());
572 if (strncmp("GET ", str, 4) == 0 ||
573 strncmp("POST ", str, 5) == 0 ||
574 strncmp("HEAD ", str, 5) == 0 ||
575 strncmp("PUT ", str, 4) == 0) {
576 OPENSSL_PUT_ERROR(SSL, SSL_R_HTTP_REQUEST);
577 *out_alert = 0;
578 return ssl_open_record_error;
579 }
580 if (strncmp("CONNE", str, 5) == 0) {
581 OPENSSL_PUT_ERROR(SSL, SSL_R_HTTPS_PROXY_REQUEST);
582 *out_alert = 0;
583 return ssl_open_record_error;
584 }
585
586 // Check for a V2ClientHello.
587 if ((in[0] & 0x80) != 0 && in[2] == SSL2_MT_CLIENT_HELLO &&
588 in[3] == SSL3_VERSION_MAJOR) {
589 auto ret = read_v2_client_hello(ssl, out_consumed, in);
590 if (ret == ssl_open_record_error) {
591 *out_alert = 0;
592 } else if (ret == ssl_open_record_success) {
593 ssl->s3->v2_hello_done = true;
594 }
595 return ret;
596 }
597
598 ssl->s3->v2_hello_done = true;
599 }
600
601 uint8_t type;
602 Span<uint8_t> body;
603 auto ret = tls_open_record(ssl, &type, &body, out_consumed, out_alert, in);
604 if (ret != ssl_open_record_success) {
605 return ret;
606 }
607
608 // WatchGuard's TLS 1.3 interference bug is very distinctive: they drop the
609 // ServerHello and send the remaining encrypted application data records
610 // as-is. This manifests as an application data record when we expect
611 // handshake. Report a dedicated error code for this case.
612 if (!ssl->server && type == SSL3_RT_APPLICATION_DATA &&
613 ssl->s3->aead_read_ctx->is_null_cipher()) {
614 OPENSSL_PUT_ERROR(SSL, SSL_R_APPLICATION_DATA_INSTEAD_OF_HANDSHAKE);
615 *out_alert = SSL_AD_UNEXPECTED_MESSAGE;
616 return ssl_open_record_error;
617 }
618
619 if (type != SSL3_RT_HANDSHAKE) {
620 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD);
621 *out_alert = SSL_AD_UNEXPECTED_MESSAGE;
622 return ssl_open_record_error;
623 }
624
625 // Append the entire handshake record to the buffer.
626 if (!tls_append_handshake_data(ssl, body)) {
627 *out_alert = SSL_AD_INTERNAL_ERROR;
628 return ssl_open_record_error;
629 }
630
631 return ssl_open_record_success;
632}
633
634void ssl3_next_message(SSL *ssl) {
635 SSLMessage msg;
636 if (!ssl3_get_message(ssl, &msg) ||
637 !ssl->s3->hs_buf ||
638 ssl->s3->hs_buf->length < CBS_len(&msg.raw)) {
639 assert(0);
640 return;
641 }
642
643 OPENSSL_memmove(ssl->s3->hs_buf->data,
644 ssl->s3->hs_buf->data + CBS_len(&msg.raw),
645 ssl->s3->hs_buf->length - CBS_len(&msg.raw));
646 ssl->s3->hs_buf->length -= CBS_len(&msg.raw);
647 ssl->s3->is_v2_hello = false;
648 ssl->s3->has_message = false;
649
650 // Post-handshake messages are rare, so release the buffer after every
651 // message. During the handshake, |on_handshake_complete| will release it.
652 if (!SSL_in_init(ssl) && ssl->s3->hs_buf->length == 0) {
653 ssl->s3->hs_buf.reset();
654 }
655}
656
657// CipherScorer produces a "score" for each possible cipher suite offered by
658// the client.
659class CipherScorer {
660 public:
661 CipherScorer(uint16_t group_id)
662 : aes_is_fine_(EVP_has_aes_hardware()),
663 security_128_is_fine_(group_id != SSL_CURVE_CECPQ2 &&
664 group_id != SSL_CURVE_CECPQ2b) {}
665
666 typedef std::tuple<bool, bool, bool> Score;
667
668 // MinScore returns a |Score| that will compare less than the score of all
669 // cipher suites.
670 Score MinScore() const {
671 return Score(false, false, false);
672 }
673
674 Score Evaluate(const SSL_CIPHER *a) const {
675 return Score(
676 // Something is always preferable to nothing.
677 true,
678 // Either 128-bit is fine, or 256-bit is preferred.
679 security_128_is_fine_ || a->algorithm_enc != SSL_AES128GCM,
680 // Either AES is fine, or else ChaCha20 is preferred.
681 aes_is_fine_ || a->algorithm_enc == SSL_CHACHA20POLY1305);
682 }
683
684 private:
685 const bool aes_is_fine_;
686 const bool security_128_is_fine_;
687};
688
689const SSL_CIPHER *ssl_choose_tls13_cipher(CBS cipher_suites, uint16_t version,
690 uint16_t group_id) {
691 if (CBS_len(&cipher_suites) % 2 != 0) {
692 return nullptr;
693 }
694
695 const SSL_CIPHER *best = nullptr;
696 CipherScorer scorer(group_id);
697 CipherScorer::Score best_score = scorer.MinScore();
698
699 while (CBS_len(&cipher_suites) > 0) {
700 uint16_t cipher_suite;
701 if (!CBS_get_u16(&cipher_suites, &cipher_suite)) {
702 return nullptr;
703 }
704
705 // Limit to TLS 1.3 ciphers we know about.
706 const SSL_CIPHER *candidate = SSL_get_cipher_by_value(cipher_suite);
707 if (candidate == nullptr ||
708 SSL_CIPHER_get_min_version(candidate) > version ||
709 SSL_CIPHER_get_max_version(candidate) < version) {
710 continue;
711 }
712
713 const CipherScorer::Score candidate_score = scorer.Evaluate(candidate);
714 // |candidate_score| must be larger to displace the current choice. That way
715 // the client's order controls between ciphers with an equal score.
716 if (candidate_score > best_score) {
717 best = candidate;
718 best_score = candidate_score;
719 }
720 }
721
722 return best;
723}
724
725BSSL_NAMESPACE_END
726