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(p: 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(buf: ssl->s3->pending_flight.get(), cap: new_cap) ||
160 !tls_seal_record(ssl,
161 out: (uint8_t *)ssl->s3->pending_flight->data +
162 ssl->s3->pending_flight->length,
163 out_len: &len, max_out, type, in: in.data(), in_len: in.size())) {
164 return false;
165 }
166
167 ssl->s3->pending_flight->length += len;
168 return true;
169}
170
171bool tls_init_message(const 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, initial_capacity: 64) ||
174 !CBB_add_u8(cbb, value: type) ||
175 !CBB_add_u24_length_prefixed(cbb, out_contents: 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 tls_finish_message(const SSL *ssl, CBB *cbb, Array<uint8_t> *out_msg) {
185 return CBBFinishArray(cbb, out: out_msg);
186}
187
188bool tls_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(pos: 0, len: ssl->max_send_fragment);
201 rest = rest.subspan(pos: chunk.size());
202
203 if (!add_record_to_flight(ssl, SSL3_RT_HANDSHAKE, in: 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(pos: 0, len: ssl->max_send_fragment - pending_len);
220 assert(!chunk.empty());
221 rest = rest.subspan(pos: chunk.size());
222
223 if (!ssl->s3->pending_hs_data) {
224 ssl->s3->pending_hs_data.reset(p: BUF_MEM_new());
225 }
226 if (!ssl->s3->pending_hs_data ||
227 !BUF_MEM_append(buf: ssl->s3->pending_hs_data.get(), in: chunk.data(),
228 len: chunk.size())) {
229 return false;
230 }
231 }
232 }
233
234 ssl_do_msg_callback(ssl, is_write: 1 /* write */, SSL3_RT_HANDSHAKE, in: 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(in: 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(ptr: reinterpret_cast<const uint8_t *>(pending_hs_data->data),
252 size: pending_hs_data->length);
253 if (ssl->quic_method) {
254 if ((ssl->s3->hs == nullptr || !ssl->s3->hs->hints_requested) &&
255 !ssl->quic_method->add_handshake_data(ssl, ssl->s3->write_level,
256 data.data(), data.size())) {
257 OPENSSL_PUT_ERROR(SSL, SSL_R_QUIC_INTERNAL_ERROR);
258 return false;
259 }
260 return true;
261 }
262
263 return add_record_to_flight(ssl, SSL3_RT_HANDSHAKE, in: data);
264}
265
266bool tls_add_change_cipher_spec(SSL *ssl) {
267 static const uint8_t kChangeCipherSpec[1] = {SSL3_MT_CCS};
268
269 if (!tls_flush_pending_hs_data(ssl)) {
270 return false;
271 }
272
273 if (!ssl->quic_method &&
274 !add_record_to_flight(ssl, SSL3_RT_CHANGE_CIPHER_SPEC,
275 in: kChangeCipherSpec)) {
276 return false;
277 }
278
279 ssl_do_msg_callback(ssl, is_write: 1 /* write */, SSL3_RT_CHANGE_CIPHER_SPEC,
280 in: kChangeCipherSpec);
281 return true;
282}
283
284int tls_flush_flight(SSL *ssl) {
285 if (!tls_flush_pending_hs_data(ssl)) {
286 return -1;
287 }
288
289 if (ssl->quic_method) {
290 if (ssl->s3->write_shutdown != ssl_shutdown_none) {
291 OPENSSL_PUT_ERROR(SSL, SSL_R_PROTOCOL_IS_SHUTDOWN);
292 return -1;
293 }
294
295 if (!ssl->quic_method->flush_flight(ssl)) {
296 OPENSSL_PUT_ERROR(SSL, SSL_R_QUIC_INTERNAL_ERROR);
297 return -1;
298 }
299 }
300
301 if (ssl->s3->pending_flight == nullptr) {
302 return 1;
303 }
304
305 if (ssl->s3->write_shutdown != ssl_shutdown_none) {
306 OPENSSL_PUT_ERROR(SSL, SSL_R_PROTOCOL_IS_SHUTDOWN);
307 return -1;
308 }
309
310 static_assert(INT_MAX <= 0xffffffff, "int is larger than 32 bits");
311 if (ssl->s3->pending_flight->length > INT_MAX) {
312 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
313 return -1;
314 }
315
316 // If there is pending data in the write buffer, it must be flushed out before
317 // any new data in pending_flight.
318 if (!ssl->s3->write_buffer.empty()) {
319 int ret = ssl_write_buffer_flush(ssl);
320 if (ret <= 0) {
321 ssl->s3->rwstate = SSL_ERROR_WANT_WRITE;
322 return ret;
323 }
324 }
325
326 if (ssl->wbio == nullptr) {
327 OPENSSL_PUT_ERROR(SSL, SSL_R_BIO_NOT_SET);
328 return -1;
329 }
330
331 // Write the pending flight.
332 while (ssl->s3->pending_flight_offset < ssl->s3->pending_flight->length) {
333 int ret = BIO_write(
334 bio: ssl->wbio.get(),
335 data: ssl->s3->pending_flight->data + ssl->s3->pending_flight_offset,
336 len: ssl->s3->pending_flight->length - ssl->s3->pending_flight_offset);
337 if (ret <= 0) {
338 ssl->s3->rwstate = SSL_ERROR_WANT_WRITE;
339 return ret;
340 }
341
342 ssl->s3->pending_flight_offset += ret;
343 }
344
345 if (BIO_flush(bio: ssl->wbio.get()) <= 0) {
346 ssl->s3->rwstate = SSL_ERROR_WANT_WRITE;
347 return -1;
348 }
349
350 ssl->s3->pending_flight.reset();
351 ssl->s3->pending_flight_offset = 0;
352 return 1;
353}
354
355static ssl_open_record_t read_v2_client_hello(SSL *ssl, size_t *out_consumed,
356 Span<const uint8_t> in) {
357 *out_consumed = 0;
358 assert(in.size() >= SSL3_RT_HEADER_LENGTH);
359 // Determine the length of the V2ClientHello.
360 size_t msg_length = ((in[0] & 0x7f) << 8) | in[1];
361 if (msg_length > (1024 * 4)) {
362 OPENSSL_PUT_ERROR(SSL, SSL_R_RECORD_TOO_LARGE);
363 return ssl_open_record_error;
364 }
365 if (msg_length < SSL3_RT_HEADER_LENGTH - 2) {
366 // Reject lengths that are too short early. We have already read
367 // |SSL3_RT_HEADER_LENGTH| bytes, so we should not attempt to process an
368 // (invalid) V2ClientHello which would be shorter than that.
369 OPENSSL_PUT_ERROR(SSL, SSL_R_RECORD_LENGTH_MISMATCH);
370 return ssl_open_record_error;
371 }
372
373 // Ask for the remainder of the V2ClientHello.
374 if (in.size() < 2 + msg_length) {
375 *out_consumed = 2 + msg_length;
376 return ssl_open_record_partial;
377 }
378
379 CBS v2_client_hello = CBS(ssl->s3->read_buffer.span().subspan(pos: 2, len: msg_length));
380 // The V2ClientHello without the length is incorporated into the handshake
381 // hash. This is only ever called at the start of the handshake, so hs is
382 // guaranteed to be non-NULL.
383 if (!ssl->s3->hs->transcript.Update(in: v2_client_hello)) {
384 return ssl_open_record_error;
385 }
386
387 ssl_do_msg_callback(ssl, is_write: 0 /* read */, content_type: 0 /* V2ClientHello */,
388 in: v2_client_hello);
389
390 uint8_t msg_type;
391 uint16_t version, cipher_spec_length, session_id_length, challenge_length;
392 CBS cipher_specs, session_id, challenge;
393 if (!CBS_get_u8(cbs: &v2_client_hello, out: &msg_type) ||
394 !CBS_get_u16(cbs: &v2_client_hello, out: &version) ||
395 !CBS_get_u16(cbs: &v2_client_hello, out: &cipher_spec_length) ||
396 !CBS_get_u16(cbs: &v2_client_hello, out: &session_id_length) ||
397 !CBS_get_u16(cbs: &v2_client_hello, out: &challenge_length) ||
398 !CBS_get_bytes(cbs: &v2_client_hello, out: &cipher_specs, len: cipher_spec_length) ||
399 !CBS_get_bytes(cbs: &v2_client_hello, out: &session_id, len: session_id_length) ||
400 !CBS_get_bytes(cbs: &v2_client_hello, out: &challenge, len: challenge_length) ||
401 CBS_len(cbs: &v2_client_hello) != 0) {
402 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
403 return ssl_open_record_error;
404 }
405
406 // msg_type has already been checked.
407 assert(msg_type == SSL2_MT_CLIENT_HELLO);
408
409 // The client_random is the V2ClientHello challenge. Truncate or left-pad with
410 // zeros as needed.
411 size_t rand_len = CBS_len(cbs: &challenge);
412 if (rand_len > SSL3_RANDOM_SIZE) {
413 rand_len = SSL3_RANDOM_SIZE;
414 }
415 uint8_t random[SSL3_RANDOM_SIZE];
416 OPENSSL_memset(dst: random, c: 0, SSL3_RANDOM_SIZE);
417 OPENSSL_memcpy(dst: random + (SSL3_RANDOM_SIZE - rand_len), src: CBS_data(cbs: &challenge),
418 n: rand_len);
419
420 // Write out an equivalent TLS ClientHello directly to the handshake buffer.
421 size_t max_v3_client_hello = SSL3_HM_HEADER_LENGTH + 2 /* version */ +
422 SSL3_RANDOM_SIZE + 1 /* session ID length */ +
423 2 /* cipher list length */ +
424 CBS_len(cbs: &cipher_specs) / 3 * 2 +
425 1 /* compression length */ + 1 /* compression */;
426 ScopedCBB client_hello;
427 CBB hello_body, cipher_suites;
428 if (!ssl->s3->hs_buf) {
429 ssl->s3->hs_buf.reset(p: BUF_MEM_new());
430 }
431 if (!ssl->s3->hs_buf ||
432 !BUF_MEM_reserve(buf: ssl->s3->hs_buf.get(), cap: max_v3_client_hello) ||
433 !CBB_init_fixed(cbb: client_hello.get(), buf: (uint8_t *)ssl->s3->hs_buf->data,
434 len: ssl->s3->hs_buf->max) ||
435 !CBB_add_u8(cbb: client_hello.get(), SSL3_MT_CLIENT_HELLO) ||
436 !CBB_add_u24_length_prefixed(cbb: client_hello.get(), out_contents: &hello_body) ||
437 !CBB_add_u16(cbb: &hello_body, value: version) ||
438 !CBB_add_bytes(cbb: &hello_body, data: random, SSL3_RANDOM_SIZE) ||
439 // No session id.
440 !CBB_add_u8(cbb: &hello_body, value: 0) ||
441 !CBB_add_u16_length_prefixed(cbb: &hello_body, out_contents: &cipher_suites)) {
442 return ssl_open_record_error;
443 }
444
445 // Copy the cipher suites.
446 while (CBS_len(cbs: &cipher_specs) > 0) {
447 uint32_t cipher_spec;
448 if (!CBS_get_u24(cbs: &cipher_specs, out: &cipher_spec)) {
449 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
450 return ssl_open_record_error;
451 }
452
453 // Skip SSLv2 ciphers.
454 if ((cipher_spec & 0xff0000) != 0) {
455 continue;
456 }
457 if (!CBB_add_u16(cbb: &cipher_suites, value: cipher_spec)) {
458 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
459 return ssl_open_record_error;
460 }
461 }
462
463 // Add the null compression scheme and finish.
464 if (!CBB_add_u8(cbb: &hello_body, value: 1) ||
465 !CBB_add_u8(cbb: &hello_body, value: 0) ||
466 !CBB_finish(cbb: client_hello.get(), NULL, out_len: &ssl->s3->hs_buf->length)) {
467 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
468 return ssl_open_record_error;
469 }
470
471 *out_consumed = 2 + msg_length;
472 ssl->s3->is_v2_hello = true;
473 return ssl_open_record_success;
474}
475
476static bool parse_message(const SSL *ssl, SSLMessage *out,
477 size_t *out_bytes_needed) {
478 if (!ssl->s3->hs_buf) {
479 *out_bytes_needed = 4;
480 return false;
481 }
482
483 CBS cbs;
484 uint32_t len;
485 CBS_init(cbs: &cbs, data: reinterpret_cast<const uint8_t *>(ssl->s3->hs_buf->data),
486 len: ssl->s3->hs_buf->length);
487 if (!CBS_get_u8(cbs: &cbs, out: &out->type) ||
488 !CBS_get_u24(cbs: &cbs, out: &len)) {
489 *out_bytes_needed = 4;
490 return false;
491 }
492
493 if (!CBS_get_bytes(cbs: &cbs, out: &out->body, len)) {
494 *out_bytes_needed = 4 + len;
495 return false;
496 }
497
498 CBS_init(cbs: &out->raw, data: reinterpret_cast<const uint8_t *>(ssl->s3->hs_buf->data),
499 len: 4 + len);
500 out->is_v2_hello = ssl->s3->is_v2_hello;
501 return true;
502}
503
504bool tls_get_message(const SSL *ssl, SSLMessage *out) {
505 size_t unused;
506 if (!parse_message(ssl, out, out_bytes_needed: &unused)) {
507 return false;
508 }
509 if (!ssl->s3->has_message) {
510 if (!out->is_v2_hello) {
511 ssl_do_msg_callback(ssl, is_write: 0 /* read */, SSL3_RT_HANDSHAKE, in: out->raw);
512 }
513 ssl->s3->has_message = true;
514 }
515 return true;
516}
517
518bool tls_can_accept_handshake_data(const SSL *ssl, uint8_t *out_alert) {
519 // If there is a complete message, the caller must have consumed it first.
520 SSLMessage msg;
521 size_t bytes_needed;
522 if (parse_message(ssl, out: &msg, out_bytes_needed: &bytes_needed)) {
523 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
524 *out_alert = SSL_AD_INTERNAL_ERROR;
525 return false;
526 }
527
528 // Enforce the limit so the peer cannot force us to buffer 16MB.
529 if (bytes_needed > 4 + ssl_max_handshake_message_len(ssl)) {
530 OPENSSL_PUT_ERROR(SSL, SSL_R_EXCESSIVE_MESSAGE_SIZE);
531 *out_alert = SSL_AD_ILLEGAL_PARAMETER;
532 return false;
533 }
534
535 return true;
536}
537
538bool tls_has_unprocessed_handshake_data(const SSL *ssl) {
539 size_t msg_len = 0;
540 if (ssl->s3->has_message) {
541 SSLMessage msg;
542 size_t unused;
543 if (parse_message(ssl, out: &msg, out_bytes_needed: &unused)) {
544 msg_len = CBS_len(cbs: &msg.raw);
545 }
546 }
547
548 return ssl->s3->hs_buf && ssl->s3->hs_buf->length > msg_len;
549}
550
551bool tls_append_handshake_data(SSL *ssl, Span<const uint8_t> data) {
552 // Re-create the handshake buffer if needed.
553 if (!ssl->s3->hs_buf) {
554 ssl->s3->hs_buf.reset(p: BUF_MEM_new());
555 }
556 return ssl->s3->hs_buf &&
557 BUF_MEM_append(buf: ssl->s3->hs_buf.get(), in: data.data(), len: data.size());
558}
559
560ssl_open_record_t tls_open_handshake(SSL *ssl, size_t *out_consumed,
561 uint8_t *out_alert, Span<uint8_t> in) {
562 *out_consumed = 0;
563 // Bypass the record layer for the first message to handle V2ClientHello.
564 if (ssl->server && !ssl->s3->v2_hello_done) {
565 // Ask for the first 5 bytes, the size of the TLS record header. This is
566 // sufficient to detect a V2ClientHello and ensures that we never read
567 // beyond the first record.
568 if (in.size() < SSL3_RT_HEADER_LENGTH) {
569 *out_consumed = SSL3_RT_HEADER_LENGTH;
570 return ssl_open_record_partial;
571 }
572
573 // Some dedicated error codes for protocol mixups should the application
574 // wish to interpret them differently. (These do not overlap with
575 // ClientHello or V2ClientHello.)
576 const char *str = reinterpret_cast<const char*>(in.data());
577 if (strncmp(s1: "GET ", s2: str, n: 4) == 0 ||
578 strncmp(s1: "POST ", s2: str, n: 5) == 0 ||
579 strncmp(s1: "HEAD ", s2: str, n: 5) == 0 ||
580 strncmp(s1: "PUT ", s2: str, n: 4) == 0) {
581 OPENSSL_PUT_ERROR(SSL, SSL_R_HTTP_REQUEST);
582 *out_alert = 0;
583 return ssl_open_record_error;
584 }
585 if (strncmp(s1: "CONNE", s2: str, n: 5) == 0) {
586 OPENSSL_PUT_ERROR(SSL, SSL_R_HTTPS_PROXY_REQUEST);
587 *out_alert = 0;
588 return ssl_open_record_error;
589 }
590
591 // Check for a V2ClientHello.
592 if ((in[0] & 0x80) != 0 && in[2] == SSL2_MT_CLIENT_HELLO &&
593 in[3] == SSL3_VERSION_MAJOR) {
594 auto ret = read_v2_client_hello(ssl, out_consumed, in);
595 if (ret == ssl_open_record_error) {
596 *out_alert = 0;
597 } else if (ret == ssl_open_record_success) {
598 ssl->s3->v2_hello_done = true;
599 }
600 return ret;
601 }
602
603 ssl->s3->v2_hello_done = true;
604 }
605
606 uint8_t type;
607 Span<uint8_t> body;
608 auto ret = tls_open_record(ssl, out_type: &type, out: &body, out_consumed, out_alert, in);
609 if (ret != ssl_open_record_success) {
610 return ret;
611 }
612
613 // WatchGuard's TLS 1.3 interference bug is very distinctive: they drop the
614 // ServerHello and send the remaining encrypted application data records
615 // as-is. This manifests as an application data record when we expect
616 // handshake. Report a dedicated error code for this case.
617 if (!ssl->server && type == SSL3_RT_APPLICATION_DATA &&
618 ssl->s3->aead_read_ctx->is_null_cipher()) {
619 OPENSSL_PUT_ERROR(SSL, SSL_R_APPLICATION_DATA_INSTEAD_OF_HANDSHAKE);
620 *out_alert = SSL_AD_UNEXPECTED_MESSAGE;
621 return ssl_open_record_error;
622 }
623
624 if (type != SSL3_RT_HANDSHAKE) {
625 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD);
626 *out_alert = SSL_AD_UNEXPECTED_MESSAGE;
627 return ssl_open_record_error;
628 }
629
630 // Append the entire handshake record to the buffer.
631 if (!tls_append_handshake_data(ssl, data: body)) {
632 *out_alert = SSL_AD_INTERNAL_ERROR;
633 return ssl_open_record_error;
634 }
635
636 return ssl_open_record_success;
637}
638
639void tls_next_message(SSL *ssl) {
640 SSLMessage msg;
641 if (!tls_get_message(ssl, out: &msg) ||
642 !ssl->s3->hs_buf ||
643 ssl->s3->hs_buf->length < CBS_len(cbs: &msg.raw)) {
644 assert(0);
645 return;
646 }
647
648 OPENSSL_memmove(dst: ssl->s3->hs_buf->data,
649 src: ssl->s3->hs_buf->data + CBS_len(cbs: &msg.raw),
650 n: ssl->s3->hs_buf->length - CBS_len(cbs: &msg.raw));
651 ssl->s3->hs_buf->length -= CBS_len(cbs: &msg.raw);
652 ssl->s3->is_v2_hello = false;
653 ssl->s3->has_message = false;
654
655 // Post-handshake messages are rare, so release the buffer after every
656 // message. During the handshake, |on_handshake_complete| will release it.
657 if (!SSL_in_init(ssl) && ssl->s3->hs_buf->length == 0) {
658 ssl->s3->hs_buf.reset();
659 }
660}
661
662// CipherScorer produces a "score" for each possible cipher suite offered by
663// the client.
664class CipherScorer {
665 public:
666 CipherScorer() : aes_is_fine_(EVP_has_aes_hardware()) {}
667
668 typedef std::tuple<bool, bool> Score;
669
670 // MinScore returns a |Score| that will compare less than the score of all
671 // cipher suites.
672 Score MinScore() const {
673 return Score(false, false);
674 }
675
676 Score Evaluate(const SSL_CIPHER *a) const {
677 return Score(
678 // Something is always preferable to nothing.
679 true,
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};
687
688bool ssl_tls13_cipher_meets_policy(uint16_t cipher_id, bool only_fips) {
689 if (!only_fips) {
690 return true;
691 }
692
693 switch (cipher_id) {
694 case TLS1_3_CK_AES_128_GCM_SHA256 & 0xffff:
695 case TLS1_3_CK_AES_256_GCM_SHA384 & 0xffff:
696 return true;
697 case TLS1_3_CK_CHACHA20_POLY1305_SHA256 & 0xffff:
698 return false;
699 default:
700 assert(false);
701 return false;
702 }
703}
704
705const SSL_CIPHER *ssl_choose_tls13_cipher(CBS cipher_suites, uint16_t version,
706 uint16_t group_id, bool only_fips) {
707 if (CBS_len(cbs: &cipher_suites) % 2 != 0) {
708 return nullptr;
709 }
710
711 const SSL_CIPHER *best = nullptr;
712 CipherScorer scorer;
713 CipherScorer::Score best_score = scorer.MinScore();
714
715 while (CBS_len(cbs: &cipher_suites) > 0) {
716 uint16_t cipher_suite;
717 if (!CBS_get_u16(cbs: &cipher_suites, out: &cipher_suite)) {
718 return nullptr;
719 }
720
721 // Limit to TLS 1.3 ciphers we know about.
722 const SSL_CIPHER *candidate = SSL_get_cipher_by_value(value: cipher_suite);
723 if (candidate == nullptr ||
724 SSL_CIPHER_get_min_version(cipher: candidate) > version ||
725 SSL_CIPHER_get_max_version(cipher: candidate) < version) {
726 continue;
727 }
728
729 if (!ssl_tls13_cipher_meets_policy(cipher_id: SSL_CIPHER_get_protocol_id(cipher: candidate),
730 only_fips)) {
731 continue;
732 }
733
734 const CipherScorer::Score candidate_score = scorer.Evaluate(a: candidate);
735 // |candidate_score| must be larger to displace the current choice. That way
736 // the client's order controls between ciphers with an equal score.
737 if (candidate_score > best_score) {
738 best = candidate;
739 best_score = candidate_score;
740 }
741 }
742
743 return best;
744}
745
746BSSL_NAMESPACE_END
747

source code of flutter_engine/third_party/boringssl/src/ssl/s3_both.cc