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) 1998-2007 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 */
110/* ====================================================================
111 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
112 *
113 * Portions of the attached software ("Contribution") are developed by
114 * SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project.
115 *
116 * The Contribution is licensed pursuant to the OpenSSL open source
117 * license provided above.
118 *
119 * ECC cipher suite support in OpenSSL originally written by
120 * Vipul Gupta and Sumit Gupta of Sun Microsystems Laboratories.
121 *
122 */
123/* ====================================================================
124 * Copyright 2005 Nokia. All rights reserved.
125 *
126 * The portions of the attached software ("Contribution") is developed by
127 * Nokia Corporation and is licensed pursuant to the OpenSSL open source
128 * license.
129 *
130 * The Contribution, originally written by Mika Kousa and Pasi Eronen of
131 * Nokia Corporation, consists of the "PSK" (Pre-Shared Key) ciphersuites
132 * support (see RFC 4279) to OpenSSL.
133 *
134 * No patent licenses or other rights except those expressly stated in
135 * the OpenSSL open source license shall be deemed granted or received
136 * expressly, by implication, estoppel, or otherwise.
137 *
138 * No assurances are provided by Nokia that the Contribution does not
139 * infringe the patent or other intellectual property rights of any third
140 * party or that the license provides you with all the necessary rights
141 * to make use of the Contribution.
142 *
143 * THE SOFTWARE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. IN
144 * ADDITION TO THE DISCLAIMERS INCLUDED IN THE LICENSE, NOKIA
145 * SPECIFICALLY DISCLAIMS ANY LIABILITY FOR CLAIMS BROUGHT BY YOU OR ANY
146 * OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OR
147 * OTHERWISE.
148 */
149
150#include <openssl/ssl.h>
151
152#include <assert.h>
153#include <limits.h>
154#include <string.h>
155
156#include <utility>
157
158#include <openssl/aead.h>
159#include <openssl/bn.h>
160#include <openssl/bytestring.h>
161#include <openssl/ec_key.h>
162#include <openssl/ecdsa.h>
163#include <openssl/err.h>
164#include <openssl/evp.h>
165#include <openssl/hpke.h>
166#include <openssl/md5.h>
167#include <openssl/mem.h>
168#include <openssl/rand.h>
169#include <openssl/sha.h>
170
171#include "../crypto/internal.h"
172#include "internal.h"
173
174
175BSSL_NAMESPACE_BEGIN
176
177enum ssl_client_hs_state_t {
178 state_start_connect = 0,
179 state_enter_early_data,
180 state_early_reverify_server_certificate,
181 state_read_hello_verify_request,
182 state_read_server_hello,
183 state_tls13,
184 state_read_server_certificate,
185 state_read_certificate_status,
186 state_verify_server_certificate,
187 state_reverify_server_certificate,
188 state_read_server_key_exchange,
189 state_read_certificate_request,
190 state_read_server_hello_done,
191 state_send_client_certificate,
192 state_send_client_key_exchange,
193 state_send_client_certificate_verify,
194 state_send_client_finished,
195 state_finish_flight,
196 state_read_session_ticket,
197 state_process_change_cipher_spec,
198 state_read_server_finished,
199 state_finish_client_handshake,
200 state_done,
201};
202
203// ssl_get_client_disabled sets |*out_mask_a| and |*out_mask_k| to masks of
204// disabled algorithms.
205static void ssl_get_client_disabled(const SSL_HANDSHAKE *hs,
206 uint32_t *out_mask_a,
207 uint32_t *out_mask_k) {
208 *out_mask_a = 0;
209 *out_mask_k = 0;
210
211 // PSK requires a client callback.
212 if (hs->config->psk_client_callback == NULL) {
213 *out_mask_a |= SSL_aPSK;
214 *out_mask_k |= SSL_kPSK;
215 }
216}
217
218static bool ssl_write_client_cipher_list(const SSL_HANDSHAKE *hs, CBB *out,
219 ssl_client_hello_type_t type) {
220 const SSL *const ssl = hs->ssl;
221 uint32_t mask_a, mask_k;
222 ssl_get_client_disabled(hs, out_mask_a: &mask_a, out_mask_k: &mask_k);
223
224 CBB child;
225 if (!CBB_add_u16_length_prefixed(cbb: out, out_contents: &child)) {
226 return false;
227 }
228
229 // Add a fake cipher suite. See RFC 8701.
230 if (ssl->ctx->grease_enabled &&
231 !CBB_add_u16(cbb: &child, value: ssl_get_grease_value(hs, index: ssl_grease_cipher))) {
232 return false;
233 }
234
235 // Add TLS 1.3 ciphers. Order ChaCha20-Poly1305 relative to AES-GCM based on
236 // hardware support.
237 if (hs->max_version >= TLS1_3_VERSION) {
238 const bool include_chacha20 = ssl_tls13_cipher_meets_policy(
239 TLS1_3_CK_CHACHA20_POLY1305_SHA256 & 0xffff,
240 only_fips: ssl->config->only_fips_cipher_suites_in_tls13);
241
242 if (!EVP_has_aes_hardware() && //
243 include_chacha20 && //
244 !CBB_add_u16(cbb: &child, TLS1_3_CK_CHACHA20_POLY1305_SHA256 & 0xffff)) {
245 return false;
246 }
247 if (!CBB_add_u16(cbb: &child, TLS1_3_CK_AES_128_GCM_SHA256 & 0xffff) ||
248 !CBB_add_u16(cbb: &child, TLS1_3_CK_AES_256_GCM_SHA384 & 0xffff)) {
249 return false;
250 }
251 if (EVP_has_aes_hardware() && //
252 include_chacha20 && //
253 !CBB_add_u16(cbb: &child, TLS1_3_CK_CHACHA20_POLY1305_SHA256 & 0xffff)) {
254 return false;
255 }
256 }
257
258 if (hs->min_version < TLS1_3_VERSION && type != ssl_client_hello_inner) {
259 bool any_enabled = false;
260 for (const SSL_CIPHER *cipher : SSL_get_ciphers(ssl)) {
261 // Skip disabled ciphers
262 if ((cipher->algorithm_mkey & mask_k) ||
263 (cipher->algorithm_auth & mask_a)) {
264 continue;
265 }
266 if (SSL_CIPHER_get_min_version(cipher) > hs->max_version ||
267 SSL_CIPHER_get_max_version(cipher) < hs->min_version) {
268 continue;
269 }
270 any_enabled = true;
271 if (!CBB_add_u16(cbb: &child, value: SSL_CIPHER_get_protocol_id(cipher))) {
272 return false;
273 }
274 }
275
276 // If all ciphers were disabled, return the error to the caller.
277 if (!any_enabled && hs->max_version < TLS1_3_VERSION) {
278 OPENSSL_PUT_ERROR(SSL, SSL_R_NO_CIPHERS_AVAILABLE);
279 return false;
280 }
281 }
282
283 if (ssl->mode & SSL_MODE_SEND_FALLBACK_SCSV) {
284 if (!CBB_add_u16(cbb: &child, SSL3_CK_FALLBACK_SCSV & 0xffff)) {
285 return false;
286 }
287 }
288
289 return CBB_flush(cbb: out);
290}
291
292bool ssl_write_client_hello_without_extensions(const SSL_HANDSHAKE *hs,
293 CBB *cbb,
294 ssl_client_hello_type_t type,
295 bool empty_session_id) {
296 const SSL *const ssl = hs->ssl;
297 CBB child;
298 if (!CBB_add_u16(cbb, value: hs->client_version) ||
299 !CBB_add_bytes(cbb,
300 data: type == ssl_client_hello_inner ? hs->inner_client_random
301 : ssl->s3->client_random,
302 SSL3_RANDOM_SIZE) ||
303 !CBB_add_u8_length_prefixed(cbb, out_contents: &child)) {
304 return false;
305 }
306
307 // Do not send a session ID on renegotiation.
308 if (!ssl->s3->initial_handshake_complete &&
309 !empty_session_id &&
310 !CBB_add_bytes(cbb: &child, data: hs->session_id, len: hs->session_id_len)) {
311 return false;
312 }
313
314 if (SSL_is_dtls(ssl)) {
315 if (!CBB_add_u8_length_prefixed(cbb, out_contents: &child) ||
316 !CBB_add_bytes(cbb: &child, data: hs->dtls_cookie.data(),
317 len: hs->dtls_cookie.size())) {
318 return false;
319 }
320 }
321
322 if (!ssl_write_client_cipher_list(hs, out: cbb, type) ||
323 !CBB_add_u8(cbb, value: 1 /* one compression method */) ||
324 !CBB_add_u8(cbb, value: 0 /* null compression */)) {
325 return false;
326 }
327 return true;
328}
329
330bool ssl_add_client_hello(SSL_HANDSHAKE *hs) {
331 SSL *const ssl = hs->ssl;
332 ScopedCBB cbb;
333 CBB body;
334 ssl_client_hello_type_t type = hs->selected_ech_config
335 ? ssl_client_hello_outer
336 : ssl_client_hello_unencrypted;
337 bool needs_psk_binder;
338 Array<uint8_t> msg;
339 if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_CLIENT_HELLO) ||
340 !ssl_write_client_hello_without_extensions(hs, cbb: &body, type,
341 /*empty_session_id=*/false) ||
342 !ssl_add_clienthello_tlsext(hs, out: &body, /*out_encoded=*/nullptr,
343 out_needs_psk_binder: &needs_psk_binder, type, header_len: CBB_len(cbb: &body)) ||
344 !ssl->method->finish_message(ssl, cbb.get(), &msg)) {
345 return false;
346 }
347
348 // Now that the length prefixes have been computed, fill in the placeholder
349 // PSK binder.
350 if (needs_psk_binder) {
351 // ClientHelloOuter cannot have a PSK binder. Otherwise the
352 // ClientHellOuterAAD computation would break.
353 assert(type != ssl_client_hello_outer);
354 if (!tls13_write_psk_binder(hs, transcript: hs->transcript, msg: MakeSpan(c&: msg),
355 /*out_binder_len=*/0)) {
356 return false;
357 }
358 }
359
360 return ssl->method->add_message(ssl, std::move(msg));
361}
362
363static bool parse_server_version(const SSL_HANDSHAKE *hs, uint16_t *out_version,
364 uint8_t *out_alert,
365 const ParsedServerHello &server_hello) {
366 // If the outer version is not TLS 1.2, use it.
367 // TODO(davidben): This function doesn't quite match the RFC8446 formulation.
368 if (server_hello.legacy_version != TLS1_2_VERSION) {
369 *out_version = server_hello.legacy_version;
370 return true;
371 }
372
373 SSLExtension supported_versions(TLSEXT_TYPE_supported_versions);
374 CBS extensions = server_hello.extensions;
375 if (!ssl_parse_extensions(cbs: &extensions, out_alert, extensions: {&supported_versions},
376 /*ignore_unknown=*/true)) {
377 return false;
378 }
379
380 if (!supported_versions.present) {
381 *out_version = server_hello.legacy_version;
382 return true;
383 }
384
385 if (!CBS_get_u16(cbs: &supported_versions.data, out: out_version) ||
386 CBS_len(cbs: &supported_versions.data) != 0) {
387 *out_alert = SSL_AD_DECODE_ERROR;
388 return false;
389 }
390
391 return true;
392}
393
394// should_offer_early_data returns |ssl_early_data_accepted| if |hs| should
395// offer early data, and some other reason code otherwise.
396static ssl_early_data_reason_t should_offer_early_data(
397 const SSL_HANDSHAKE *hs) {
398 const SSL *const ssl = hs->ssl;
399 assert(!ssl->server);
400 if (!ssl->enable_early_data) {
401 return ssl_early_data_disabled;
402 }
403
404 if (hs->max_version < TLS1_3_VERSION) {
405 // We discard inapplicable sessions, so this is redundant with the session
406 // checks below, but reporting that TLS 1.3 was disabled is more useful.
407 return ssl_early_data_protocol_version;
408 }
409
410 if (ssl->session == nullptr) {
411 return ssl_early_data_no_session_offered;
412 }
413
414 if (ssl_session_protocol_version(session: ssl->session.get()) < TLS1_3_VERSION ||
415 ssl->session->ticket_max_early_data == 0) {
416 return ssl_early_data_unsupported_for_session;
417 }
418
419 if (!ssl->session->early_alpn.empty()) {
420 if (!ssl_is_alpn_protocol_allowed(hs, protocol: ssl->session->early_alpn)) {
421 // Avoid reporting a confusing value in |SSL_get0_alpn_selected|.
422 return ssl_early_data_alpn_mismatch;
423 }
424
425 // If the previous connection negotiated ALPS, only offer 0-RTT when the
426 // local are settings are consistent with what we'd offer for this
427 // connection.
428 if (ssl->session->has_application_settings) {
429 Span<const uint8_t> settings;
430 if (!ssl_get_local_application_settings(hs, out_settings: &settings,
431 protocol: ssl->session->early_alpn) ||
432 settings != ssl->session->local_application_settings) {
433 return ssl_early_data_alps_mismatch;
434 }
435 }
436 }
437
438 // Early data has not yet been accepted, but we use it as a success code.
439 return ssl_early_data_accepted;
440}
441
442void ssl_done_writing_client_hello(SSL_HANDSHAKE *hs) {
443 hs->ech_client_outer.Reset();
444 hs->cookie.Reset();
445 hs->key_share_bytes.Reset();
446}
447
448static enum ssl_hs_wait_t do_start_connect(SSL_HANDSHAKE *hs) {
449 SSL *const ssl = hs->ssl;
450
451 ssl_do_info_callback(ssl, SSL_CB_HANDSHAKE_START, value: 1);
452 // |session_reused| must be reset in case this is a renegotiation.
453 ssl->s3->session_reused = false;
454
455 // Freeze the version range.
456 if (!ssl_get_version_range(hs, out_min_version: &hs->min_version, out_max_version: &hs->max_version)) {
457 return ssl_hs_error;
458 }
459
460 uint8_t ech_enc[EVP_HPKE_MAX_ENC_LENGTH];
461 size_t ech_enc_len;
462 if (!ssl_select_ech_config(hs, out_enc: ech_enc, out_enc_len: &ech_enc_len)) {
463 return ssl_hs_error;
464 }
465
466 // Always advertise the ClientHello version from the original maximum version,
467 // even on renegotiation. The static RSA key exchange uses this field, and
468 // some servers fail when it changes across handshakes.
469 if (SSL_is_dtls(ssl: hs->ssl)) {
470 hs->client_version =
471 hs->max_version >= TLS1_2_VERSION ? DTLS1_2_VERSION : DTLS1_VERSION;
472 } else {
473 hs->client_version =
474 hs->max_version >= TLS1_2_VERSION ? TLS1_2_VERSION : hs->max_version;
475 }
476
477 // If the configured session has expired or is not usable, drop it. We also do
478 // not offer sessions on renegotiation.
479 if (ssl->session != nullptr) {
480 if (ssl->session->is_server ||
481 !ssl_supports_version(hs, version: ssl->session->ssl_version) ||
482 // Do not offer TLS 1.2 sessions with ECH. ClientHelloInner does not
483 // offer TLS 1.2, and the cleartext session ID may leak the server
484 // identity.
485 (hs->selected_ech_config &&
486 ssl_session_protocol_version(session: ssl->session.get()) < TLS1_3_VERSION) ||
487 !SSL_SESSION_is_resumable(session: ssl->session.get()) ||
488 !ssl_session_is_time_valid(ssl, session: ssl->session.get()) ||
489 (ssl->quic_method != nullptr) != ssl->session->is_quic ||
490 ssl->s3->initial_handshake_complete) {
491 ssl_set_session(ssl, session: nullptr);
492 }
493 }
494
495 if (!RAND_bytes(buf: ssl->s3->client_random, len: sizeof(ssl->s3->client_random))) {
496 return ssl_hs_error;
497 }
498 if (hs->selected_ech_config &&
499 !RAND_bytes(buf: hs->inner_client_random, len: sizeof(hs->inner_client_random))) {
500 return ssl_hs_error;
501 }
502
503 // Never send a session ID in QUIC. QUIC uses TLS 1.3 at a minimum and
504 // disables TLS 1.3 middlebox compatibility mode.
505 if (ssl->quic_method == nullptr) {
506 const bool has_id_session = ssl->session != nullptr &&
507 ssl->session->session_id_length > 0 &&
508 ssl->session->ticket.empty();
509 const bool has_ticket_session =
510 ssl->session != nullptr && !ssl->session->ticket.empty();
511 if (has_id_session) {
512 hs->session_id_len = ssl->session->session_id_length;
513 OPENSSL_memcpy(dst: hs->session_id, src: ssl->session->session_id,
514 n: hs->session_id_len);
515 } else if (has_ticket_session || hs->max_version >= TLS1_3_VERSION) {
516 // Send a random session ID. TLS 1.3 always sends one, and TLS 1.2 session
517 // tickets require a placeholder value to signal resumption.
518 hs->session_id_len = sizeof(hs->session_id);
519 if (!RAND_bytes(buf: hs->session_id, len: hs->session_id_len)) {
520 return ssl_hs_error;
521 }
522 }
523 }
524
525 ssl_early_data_reason_t reason = should_offer_early_data(hs);
526 if (reason != ssl_early_data_accepted) {
527 ssl->s3->early_data_reason = reason;
528 } else {
529 hs->early_data_offered = true;
530 }
531
532 if (!ssl_setup_key_shares(hs, /*override_group_id=*/0) ||
533 !ssl_setup_extension_permutation(hs) ||
534 !ssl_encrypt_client_hello(hs, enc: MakeConstSpan(ptr: ech_enc, size: ech_enc_len)) ||
535 !ssl_add_client_hello(hs)) {
536 return ssl_hs_error;
537 }
538
539 hs->state = state_enter_early_data;
540 return ssl_hs_flush;
541}
542
543static enum ssl_hs_wait_t do_enter_early_data(SSL_HANDSHAKE *hs) {
544 SSL *const ssl = hs->ssl;
545
546 if (SSL_is_dtls(ssl)) {
547 hs->state = state_read_hello_verify_request;
548 return ssl_hs_ok;
549 }
550
551 if (!hs->early_data_offered) {
552 hs->state = state_read_server_hello;
553 return ssl_hs_ok;
554 }
555
556 ssl->s3->aead_write_ctx->SetVersionIfNullCipher(ssl->session->ssl_version);
557 if (!ssl->method->add_change_cipher_spec(ssl)) {
558 return ssl_hs_error;
559 }
560
561 if (!tls13_init_early_key_schedule(hs, session: ssl->session.get()) ||
562 !tls13_derive_early_secret(hs)) {
563 return ssl_hs_error;
564 }
565
566 // Stash the early data session, so connection properties may be queried out
567 // of it.
568 hs->early_session = UpRef(ptr: ssl->session);
569 hs->state = state_early_reverify_server_certificate;
570 return ssl_hs_ok;
571}
572
573static enum ssl_hs_wait_t do_early_reverify_server_certificate(SSL_HANDSHAKE *hs) {
574 if (hs->ssl->ctx->reverify_on_resume) {
575 // Don't send an alert on error. The alert be in early data, which the
576 // server may not accept anyway. It would also be a mismatch between QUIC
577 // and TCP because the QUIC early keys are deferred below.
578 //
579 // TODO(davidben): The client behavior should be to verify the certificate
580 // before deciding whether to offer the session and, if invalid, decline to
581 // send the session.
582 switch (ssl_reverify_peer_cert(hs, /*send_alert=*/false)) {
583 case ssl_verify_ok:
584 break;
585 case ssl_verify_invalid:
586 return ssl_hs_error;
587 case ssl_verify_retry:
588 hs->state = state_early_reverify_server_certificate;
589 return ssl_hs_certificate_verify;
590 }
591 }
592
593 // Defer releasing the 0-RTT key to after certificate reverification, so the
594 // QUIC implementation does not accidentally write data too early.
595 if (!tls13_set_traffic_key(ssl: hs->ssl, level: ssl_encryption_early_data, direction: evp_aead_seal,
596 session: hs->early_session.get(),
597 traffic_secret: hs->early_traffic_secret())) {
598 return ssl_hs_error;
599 }
600
601 hs->in_early_data = true;
602 hs->can_early_write = true;
603 hs->state = state_read_server_hello;
604 return ssl_hs_early_return;
605}
606
607static enum ssl_hs_wait_t do_read_hello_verify_request(SSL_HANDSHAKE *hs) {
608 SSL *const ssl = hs->ssl;
609
610 assert(SSL_is_dtls(ssl));
611
612 // When implementing DTLS 1.3, we need to handle the interactions between
613 // HelloVerifyRequest, DTLS 1.3's HelloVerifyRequest removal, and ECH.
614 assert(hs->max_version < TLS1_3_VERSION);
615
616 SSLMessage msg;
617 if (!ssl->method->get_message(ssl, &msg)) {
618 return ssl_hs_read_message;
619 }
620
621 if (msg.type != DTLS1_MT_HELLO_VERIFY_REQUEST) {
622 hs->state = state_read_server_hello;
623 return ssl_hs_ok;
624 }
625
626 CBS hello_verify_request = msg.body, cookie;
627 uint16_t server_version;
628 if (!CBS_get_u16(cbs: &hello_verify_request, out: &server_version) ||
629 !CBS_get_u8_length_prefixed(cbs: &hello_verify_request, out: &cookie) ||
630 CBS_len(cbs: &hello_verify_request) != 0) {
631 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
632 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
633 return ssl_hs_error;
634 }
635
636 if (!hs->dtls_cookie.CopyFrom(in: cookie)) {
637 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
638 return ssl_hs_error;
639 }
640
641 ssl->method->next_message(ssl);
642
643 // DTLS resets the handshake buffer after HelloVerifyRequest.
644 if (!hs->transcript.Init()) {
645 return ssl_hs_error;
646 }
647
648 if (!ssl_add_client_hello(hs)) {
649 return ssl_hs_error;
650 }
651
652 hs->state = state_read_server_hello;
653 return ssl_hs_flush;
654}
655
656bool ssl_parse_server_hello(ParsedServerHello *out, uint8_t *out_alert,
657 const SSLMessage &msg) {
658 if (msg.type != SSL3_MT_SERVER_HELLO) {
659 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);
660 *out_alert = SSL_AD_UNEXPECTED_MESSAGE;
661 return false;
662 }
663 out->raw = msg.raw;
664 CBS body = msg.body;
665 if (!CBS_get_u16(cbs: &body, out: &out->legacy_version) ||
666 !CBS_get_bytes(cbs: &body, out: &out->random, SSL3_RANDOM_SIZE) ||
667 !CBS_get_u8_length_prefixed(cbs: &body, out: &out->session_id) ||
668 CBS_len(cbs: &out->session_id) > SSL3_SESSION_ID_SIZE ||
669 !CBS_get_u16(cbs: &body, out: &out->cipher_suite) ||
670 !CBS_get_u8(cbs: &body, out: &out->compression_method)) {
671 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
672 *out_alert = SSL_AD_DECODE_ERROR;
673 return false;
674 }
675 // In TLS 1.2 and below, empty extensions blocks may be omitted. In TLS 1.3,
676 // ServerHellos always have extensions, so this can be applied generically.
677 CBS_init(cbs: &out->extensions, data: nullptr, len: 0);
678 if ((CBS_len(cbs: &body) != 0 &&
679 !CBS_get_u16_length_prefixed(cbs: &body, out: &out->extensions)) ||
680 CBS_len(cbs: &body) != 0) {
681 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
682 *out_alert = SSL_AD_DECODE_ERROR;
683 return false;
684 }
685 return true;
686}
687
688static enum ssl_hs_wait_t do_read_server_hello(SSL_HANDSHAKE *hs) {
689 SSL *const ssl = hs->ssl;
690 SSLMessage msg;
691 if (!ssl->method->get_message(ssl, &msg)) {
692 return ssl_hs_read_server_hello;
693 }
694
695 ParsedServerHello server_hello;
696 uint16_t server_version;
697 uint8_t alert = SSL_AD_DECODE_ERROR;
698 if (!ssl_parse_server_hello(out: &server_hello, out_alert: &alert, msg) ||
699 !parse_server_version(hs, out_version: &server_version, out_alert: &alert, server_hello)) {
700 ssl_send_alert(ssl, SSL3_AL_FATAL, desc: alert);
701 return ssl_hs_error;
702 }
703
704 if (!ssl_supports_version(hs, version: server_version)) {
705 OPENSSL_PUT_ERROR(SSL, SSL_R_UNSUPPORTED_PROTOCOL);
706 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_PROTOCOL_VERSION);
707 return ssl_hs_error;
708 }
709
710 assert(ssl->s3->have_version == ssl->s3->initial_handshake_complete);
711 if (!ssl->s3->have_version) {
712 ssl->version = server_version;
713 // At this point, the connection's version is known and ssl->version is
714 // fixed. Begin enforcing the record-layer version.
715 ssl->s3->have_version = true;
716 ssl->s3->aead_write_ctx->SetVersionIfNullCipher(ssl->version);
717 } else if (server_version != ssl->version) {
718 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SSL_VERSION);
719 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_PROTOCOL_VERSION);
720 return ssl_hs_error;
721 }
722
723 if (ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
724 hs->state = state_tls13;
725 return ssl_hs_ok;
726 }
727
728 // Clear some TLS 1.3 state that no longer needs to be retained.
729 hs->key_shares[0].reset();
730 hs->key_shares[1].reset();
731 ssl_done_writing_client_hello(hs);
732
733 // A TLS 1.2 server would not know to skip the early data we offered. Report
734 // an error code sooner. The caller may use this error code to implement the
735 // fallback described in RFC 8446 appendix D.3.
736 if (hs->early_data_offered) {
737 // Disconnect early writes. This ensures subsequent |SSL_write| calls query
738 // the handshake which, in turn, will replay the error code rather than fail
739 // at the |write_shutdown| check. See https://crbug.com/1078515.
740 // TODO(davidben): Should all handshake errors do this? What about record
741 // decryption failures?
742 hs->can_early_write = false;
743 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_VERSION_ON_EARLY_DATA);
744 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_PROTOCOL_VERSION);
745 return ssl_hs_error;
746 }
747
748 // TLS 1.2 handshakes cannot accept ECH.
749 if (hs->selected_ech_config) {
750 ssl->s3->ech_status = ssl_ech_rejected;
751 }
752
753 // Copy over the server random.
754 OPENSSL_memcpy(dst: ssl->s3->server_random, src: CBS_data(cbs: &server_hello.random),
755 SSL3_RANDOM_SIZE);
756
757 // Enforce the TLS 1.3 anti-downgrade feature.
758 if (!ssl->s3->initial_handshake_complete &&
759 ssl_supports_version(hs, TLS1_3_VERSION)) {
760 static_assert(
761 sizeof(kTLS12DowngradeRandom) == sizeof(kTLS13DowngradeRandom),
762 "downgrade signals have different size");
763 static_assert(
764 sizeof(kJDK11DowngradeRandom) == sizeof(kTLS13DowngradeRandom),
765 "downgrade signals have different size");
766 auto suffix =
767 MakeConstSpan(ptr: ssl->s3->server_random, size: sizeof(ssl->s3->server_random))
768 .subspan(SSL3_RANDOM_SIZE - sizeof(kTLS13DowngradeRandom));
769 if (suffix == kTLS12DowngradeRandom || suffix == kTLS13DowngradeRandom ||
770 suffix == kJDK11DowngradeRandom) {
771 OPENSSL_PUT_ERROR(SSL, SSL_R_TLS13_DOWNGRADE);
772 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
773 return ssl_hs_error;
774 }
775 }
776
777 // The cipher must be allowed in the selected version and enabled.
778 const SSL_CIPHER *cipher = SSL_get_cipher_by_value(value: server_hello.cipher_suite);
779 uint32_t mask_a, mask_k;
780 ssl_get_client_disabled(hs, out_mask_a: &mask_a, out_mask_k: &mask_k);
781 if (cipher == nullptr ||
782 (cipher->algorithm_mkey & mask_k) ||
783 (cipher->algorithm_auth & mask_a) ||
784 SSL_CIPHER_get_min_version(cipher) > ssl_protocol_version(ssl) ||
785 SSL_CIPHER_get_max_version(cipher) < ssl_protocol_version(ssl) ||
786 !sk_SSL_CIPHER_find(sk: SSL_get_ciphers(ssl), out_index: nullptr, p: cipher)) {
787 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CIPHER_RETURNED);
788 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
789 return ssl_hs_error;
790 }
791
792 hs->new_cipher = cipher;
793
794 if (hs->session_id_len != 0 &&
795 CBS_mem_equal(cbs: &server_hello.session_id, data: hs->session_id,
796 len: hs->session_id_len)) {
797 // Echoing the ClientHello session ID in TLS 1.2, whether from the session
798 // or a synthetic one, indicates resumption. If there was no session (or if
799 // the session was only offered in ECH ClientHelloInner), this was the
800 // TLS 1.3 compatibility mode session ID. As we know this is not a session
801 // the server knows about, any server resuming it is in error. Reject the
802 // first connection deterministicly, rather than installing an invalid
803 // session into the session cache. https://crbug.com/796910
804 if (ssl->session == nullptr || ssl->s3->ech_status == ssl_ech_rejected) {
805 OPENSSL_PUT_ERROR(SSL, SSL_R_SERVER_ECHOED_INVALID_SESSION_ID);
806 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
807 return ssl_hs_error;
808 }
809 if (ssl->session->ssl_version != ssl->version) {
810 OPENSSL_PUT_ERROR(SSL, SSL_R_OLD_SESSION_VERSION_NOT_RETURNED);
811 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
812 return ssl_hs_error;
813 }
814 if (ssl->session->cipher != hs->new_cipher) {
815 OPENSSL_PUT_ERROR(SSL, SSL_R_OLD_SESSION_CIPHER_NOT_RETURNED);
816 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
817 return ssl_hs_error;
818 }
819 if (!ssl_session_is_context_valid(hs, session: ssl->session.get())) {
820 // This is actually a client application bug.
821 OPENSSL_PUT_ERROR(SSL,
822 SSL_R_ATTEMPT_TO_REUSE_SESSION_IN_DIFFERENT_CONTEXT);
823 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
824 return ssl_hs_error;
825 }
826 // We never offer sessions on renegotiation.
827 assert(!ssl->s3->initial_handshake_complete);
828 ssl->s3->session_reused = true;
829 } else {
830 // The session wasn't resumed. Create a fresh SSL_SESSION to fill out.
831 ssl_set_session(ssl, NULL);
832 if (!ssl_get_new_session(hs)) {
833 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
834 return ssl_hs_error;
835 }
836 // Note: session_id could be empty.
837 hs->new_session->session_id_length = CBS_len(cbs: &server_hello.session_id);
838 OPENSSL_memcpy(dst: hs->new_session->session_id,
839 src: CBS_data(cbs: &server_hello.session_id),
840 n: CBS_len(cbs: &server_hello.session_id));
841 hs->new_session->cipher = hs->new_cipher;
842 }
843
844 // Now that the cipher is known, initialize the handshake hash and hash the
845 // ServerHello.
846 if (!hs->transcript.InitHash(version: ssl_protocol_version(ssl), cipher: hs->new_cipher) ||
847 !ssl_hash_message(hs, msg)) {
848 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
849 return ssl_hs_error;
850 }
851
852 // If doing a full handshake, the server may request a client certificate
853 // which requires hashing the handshake transcript. Otherwise, the handshake
854 // buffer may be released.
855 if (ssl->session != NULL ||
856 !ssl_cipher_uses_certificate_auth(cipher: hs->new_cipher)) {
857 hs->transcript.FreeBuffer();
858 }
859
860 // Only the NULL compression algorithm is supported.
861 if (server_hello.compression_method != 0) {
862 OPENSSL_PUT_ERROR(SSL, SSL_R_UNSUPPORTED_COMPRESSION_ALGORITHM);
863 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
864 return ssl_hs_error;
865 }
866
867 if (!ssl_parse_serverhello_tlsext(hs, extensions: &server_hello.extensions)) {
868 OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT);
869 return ssl_hs_error;
870 }
871
872 if (ssl->session != NULL &&
873 hs->extended_master_secret != ssl->session->extended_master_secret) {
874 if (ssl->session->extended_master_secret) {
875 OPENSSL_PUT_ERROR(SSL, SSL_R_RESUMED_EMS_SESSION_WITHOUT_EMS_EXTENSION);
876 } else {
877 OPENSSL_PUT_ERROR(SSL, SSL_R_RESUMED_NON_EMS_SESSION_WITH_EMS_EXTENSION);
878 }
879 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
880 return ssl_hs_error;
881 }
882
883 ssl->method->next_message(ssl);
884
885 if (ssl->session != NULL) {
886 if (ssl->ctx->reverify_on_resume &&
887 ssl_cipher_uses_certificate_auth(cipher: hs->new_cipher)) {
888 hs->state = state_reverify_server_certificate;
889 } else {
890 hs->state = state_read_session_ticket;
891 }
892 return ssl_hs_ok;
893 }
894
895 hs->state = state_read_server_certificate;
896 return ssl_hs_ok;
897}
898
899static enum ssl_hs_wait_t do_tls13(SSL_HANDSHAKE *hs) {
900 enum ssl_hs_wait_t wait = tls13_client_handshake(hs);
901 if (wait == ssl_hs_ok) {
902 hs->state = state_finish_client_handshake;
903 return ssl_hs_ok;
904 }
905
906 return wait;
907}
908
909static enum ssl_hs_wait_t do_read_server_certificate(SSL_HANDSHAKE *hs) {
910 SSL *const ssl = hs->ssl;
911
912 if (!ssl_cipher_uses_certificate_auth(cipher: hs->new_cipher)) {
913 hs->state = state_read_certificate_status;
914 return ssl_hs_ok;
915 }
916
917 SSLMessage msg;
918 if (!ssl->method->get_message(ssl, &msg)) {
919 return ssl_hs_read_message;
920 }
921
922 if (!ssl_check_message_type(ssl, msg, SSL3_MT_CERTIFICATE) ||
923 !ssl_hash_message(hs, msg)) {
924 return ssl_hs_error;
925 }
926
927 CBS body = msg.body;
928 uint8_t alert = SSL_AD_DECODE_ERROR;
929 if (!ssl_parse_cert_chain(out_alert: &alert, out_chain: &hs->new_session->certs, out_pubkey: &hs->peer_pubkey,
930 NULL, cbs: &body, pool: ssl->ctx->pool)) {
931 ssl_send_alert(ssl, SSL3_AL_FATAL, desc: alert);
932 return ssl_hs_error;
933 }
934
935 if (sk_CRYPTO_BUFFER_num(sk: hs->new_session->certs.get()) == 0 ||
936 CBS_len(cbs: &body) != 0 ||
937 !ssl->ctx->x509_method->session_cache_objects(hs->new_session.get())) {
938 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
939 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
940 return ssl_hs_error;
941 }
942
943 if (!ssl_check_leaf_certificate(
944 hs, pkey: hs->peer_pubkey.get(),
945 leaf: sk_CRYPTO_BUFFER_value(sk: hs->new_session->certs.get(), i: 0))) {
946 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
947 return ssl_hs_error;
948 }
949
950 ssl->method->next_message(ssl);
951
952 hs->state = state_read_certificate_status;
953 return ssl_hs_ok;
954}
955
956static enum ssl_hs_wait_t do_read_certificate_status(SSL_HANDSHAKE *hs) {
957 SSL *const ssl = hs->ssl;
958
959 if (!hs->certificate_status_expected) {
960 hs->state = state_verify_server_certificate;
961 return ssl_hs_ok;
962 }
963
964 SSLMessage msg;
965 if (!ssl->method->get_message(ssl, &msg)) {
966 return ssl_hs_read_message;
967 }
968
969 if (msg.type != SSL3_MT_CERTIFICATE_STATUS) {
970 // A server may send status_request in ServerHello and then change its mind
971 // about sending CertificateStatus.
972 hs->state = state_verify_server_certificate;
973 return ssl_hs_ok;
974 }
975
976 if (!ssl_hash_message(hs, msg)) {
977 return ssl_hs_error;
978 }
979
980 CBS certificate_status = msg.body, ocsp_response;
981 uint8_t status_type;
982 if (!CBS_get_u8(cbs: &certificate_status, out: &status_type) ||
983 status_type != TLSEXT_STATUSTYPE_ocsp ||
984 !CBS_get_u24_length_prefixed(cbs: &certificate_status, out: &ocsp_response) ||
985 CBS_len(cbs: &ocsp_response) == 0 ||
986 CBS_len(cbs: &certificate_status) != 0) {
987 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
988 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
989 return ssl_hs_error;
990 }
991
992 hs->new_session->ocsp_response.reset(
993 p: CRYPTO_BUFFER_new_from_CBS(cbs: &ocsp_response, pool: ssl->ctx->pool));
994 if (hs->new_session->ocsp_response == nullptr) {
995 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
996 return ssl_hs_error;
997 }
998
999 ssl->method->next_message(ssl);
1000
1001 hs->state = state_verify_server_certificate;
1002 return ssl_hs_ok;
1003}
1004
1005static enum ssl_hs_wait_t do_verify_server_certificate(SSL_HANDSHAKE *hs) {
1006 if (!ssl_cipher_uses_certificate_auth(cipher: hs->new_cipher)) {
1007 hs->state = state_read_server_key_exchange;
1008 return ssl_hs_ok;
1009 }
1010
1011 switch (ssl_verify_peer_cert(hs)) {
1012 case ssl_verify_ok:
1013 break;
1014 case ssl_verify_invalid:
1015 return ssl_hs_error;
1016 case ssl_verify_retry:
1017 hs->state = state_verify_server_certificate;
1018 return ssl_hs_certificate_verify;
1019 }
1020
1021 hs->state = state_read_server_key_exchange;
1022 return ssl_hs_ok;
1023}
1024
1025static enum ssl_hs_wait_t do_reverify_server_certificate(SSL_HANDSHAKE *hs) {
1026 assert(hs->ssl->ctx->reverify_on_resume);
1027
1028 switch (ssl_reverify_peer_cert(hs, /*send_alert=*/true)) {
1029 case ssl_verify_ok:
1030 break;
1031 case ssl_verify_invalid:
1032 return ssl_hs_error;
1033 case ssl_verify_retry:
1034 hs->state = state_reverify_server_certificate;
1035 return ssl_hs_certificate_verify;
1036 }
1037
1038 hs->state = state_read_session_ticket;
1039 return ssl_hs_ok;
1040}
1041
1042static enum ssl_hs_wait_t do_read_server_key_exchange(SSL_HANDSHAKE *hs) {
1043 SSL *const ssl = hs->ssl;
1044 SSLMessage msg;
1045 if (!ssl->method->get_message(ssl, &msg)) {
1046 return ssl_hs_read_message;
1047 }
1048
1049 if (msg.type != SSL3_MT_SERVER_KEY_EXCHANGE) {
1050 // Some ciphers (pure PSK) have an optional ServerKeyExchange message.
1051 if (ssl_cipher_requires_server_key_exchange(cipher: hs->new_cipher)) {
1052 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);
1053 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
1054 return ssl_hs_error;
1055 }
1056
1057 hs->state = state_read_certificate_request;
1058 return ssl_hs_ok;
1059 }
1060
1061 if (!ssl_hash_message(hs, msg)) {
1062 return ssl_hs_error;
1063 }
1064
1065 uint32_t alg_k = hs->new_cipher->algorithm_mkey;
1066 uint32_t alg_a = hs->new_cipher->algorithm_auth;
1067 CBS server_key_exchange = msg.body;
1068 if (alg_a & SSL_aPSK) {
1069 CBS psk_identity_hint;
1070
1071 // Each of the PSK key exchanges begins with a psk_identity_hint.
1072 if (!CBS_get_u16_length_prefixed(cbs: &server_key_exchange,
1073 out: &psk_identity_hint)) {
1074 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1075 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1076 return ssl_hs_error;
1077 }
1078
1079 // Store the PSK identity hint for the ClientKeyExchange. Assume that the
1080 // maximum length of a PSK identity hint can be as long as the maximum
1081 // length of a PSK identity. Also do not allow NULL characters; identities
1082 // are saved as C strings.
1083 //
1084 // TODO(davidben): Should invalid hints be ignored? It's a hint rather than
1085 // a specific identity.
1086 if (CBS_len(cbs: &psk_identity_hint) > PSK_MAX_IDENTITY_LEN ||
1087 CBS_contains_zero_byte(cbs: &psk_identity_hint)) {
1088 OPENSSL_PUT_ERROR(SSL, SSL_R_DATA_LENGTH_TOO_LONG);
1089 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
1090 return ssl_hs_error;
1091 }
1092
1093 // Save non-empty identity hints as a C string. Empty identity hints we
1094 // treat as missing. Plain PSK makes it possible to send either no hint
1095 // (omit ServerKeyExchange) or an empty hint, while ECDHE_PSK can only spell
1096 // empty hint. Having different capabilities is odd, so we interpret empty
1097 // and missing as identical.
1098 char *raw = nullptr;
1099 if (CBS_len(cbs: &psk_identity_hint) != 0 &&
1100 !CBS_strdup(cbs: &psk_identity_hint, out_ptr: &raw)) {
1101 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
1102 return ssl_hs_error;
1103 }
1104 hs->peer_psk_identity_hint.reset(p: raw);
1105 }
1106
1107 if (alg_k & SSL_kECDHE) {
1108 // Parse the server parameters.
1109 uint8_t group_type;
1110 uint16_t group_id;
1111 CBS point;
1112 if (!CBS_get_u8(cbs: &server_key_exchange, out: &group_type) ||
1113 group_type != NAMED_CURVE_TYPE ||
1114 !CBS_get_u16(cbs: &server_key_exchange, out: &group_id) ||
1115 !CBS_get_u8_length_prefixed(cbs: &server_key_exchange, out: &point)) {
1116 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1117 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1118 return ssl_hs_error;
1119 }
1120
1121 // Ensure the group is consistent with preferences.
1122 if (!tls1_check_group_id(ssl: hs, group_id)) {
1123 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CURVE);
1124 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
1125 return ssl_hs_error;
1126 }
1127
1128 // Save the group and peer public key for later.
1129 hs->new_session->group_id = group_id;
1130 if (!hs->peer_key.CopyFrom(in: point)) {
1131 return ssl_hs_error;
1132 }
1133 } else if (!(alg_k & SSL_kPSK)) {
1134 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);
1135 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
1136 return ssl_hs_error;
1137 }
1138
1139 // At this point, |server_key_exchange| contains the signature, if any, while
1140 // |msg.body| contains the entire message. From that, derive a CBS containing
1141 // just the parameter.
1142 CBS parameter;
1143 CBS_init(cbs: &parameter, data: CBS_data(cbs: &msg.body),
1144 len: CBS_len(cbs: &msg.body) - CBS_len(cbs: &server_key_exchange));
1145
1146 // ServerKeyExchange should be signed by the server's public key.
1147 if (ssl_cipher_uses_certificate_auth(cipher: hs->new_cipher)) {
1148 uint16_t signature_algorithm = 0;
1149 if (ssl_protocol_version(ssl) >= TLS1_2_VERSION) {
1150 if (!CBS_get_u16(cbs: &server_key_exchange, out: &signature_algorithm)) {
1151 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1152 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1153 return ssl_hs_error;
1154 }
1155 uint8_t alert = SSL_AD_DECODE_ERROR;
1156 if (!tls12_check_peer_sigalg(hs, out_alert: &alert, sigalg: signature_algorithm)) {
1157 ssl_send_alert(ssl, SSL3_AL_FATAL, desc: alert);
1158 return ssl_hs_error;
1159 }
1160 hs->new_session->peer_signature_algorithm = signature_algorithm;
1161 } else if (!tls1_get_legacy_signature_algorithm(out: &signature_algorithm,
1162 pkey: hs->peer_pubkey.get())) {
1163 OPENSSL_PUT_ERROR(SSL, SSL_R_PEER_ERROR_UNSUPPORTED_CERTIFICATE_TYPE);
1164 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNSUPPORTED_CERTIFICATE);
1165 return ssl_hs_error;
1166 }
1167
1168 // The last field in |server_key_exchange| is the signature.
1169 CBS signature;
1170 if (!CBS_get_u16_length_prefixed(cbs: &server_key_exchange, out: &signature) ||
1171 CBS_len(cbs: &server_key_exchange) != 0) {
1172 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1173 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1174 return ssl_hs_error;
1175 }
1176
1177 ScopedCBB transcript;
1178 Array<uint8_t> transcript_data;
1179 if (!CBB_init(cbb: transcript.get(),
1180 initial_capacity: 2 * SSL3_RANDOM_SIZE + CBS_len(cbs: &parameter)) ||
1181 !CBB_add_bytes(cbb: transcript.get(), data: ssl->s3->client_random,
1182 SSL3_RANDOM_SIZE) ||
1183 !CBB_add_bytes(cbb: transcript.get(), data: ssl->s3->server_random,
1184 SSL3_RANDOM_SIZE) ||
1185 !CBB_add_bytes(cbb: transcript.get(), data: CBS_data(cbs: &parameter),
1186 len: CBS_len(cbs: &parameter)) ||
1187 !CBBFinishArray(cbb: transcript.get(), out: &transcript_data)) {
1188 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
1189 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
1190 return ssl_hs_error;
1191 }
1192
1193 if (!ssl_public_key_verify(ssl, signature, sigalg: signature_algorithm,
1194 pkey: hs->peer_pubkey.get(), in: transcript_data)) {
1195 // bad signature
1196 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SIGNATURE);
1197 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
1198 return ssl_hs_error;
1199 }
1200 } else {
1201 // PSK ciphers are the only supported certificate-less ciphers.
1202 assert(alg_a == SSL_aPSK);
1203
1204 if (CBS_len(cbs: &server_key_exchange) > 0) {
1205 OPENSSL_PUT_ERROR(SSL, SSL_R_EXTRA_DATA_IN_MESSAGE);
1206 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1207 return ssl_hs_error;
1208 }
1209 }
1210
1211 ssl->method->next_message(ssl);
1212 hs->state = state_read_certificate_request;
1213 return ssl_hs_ok;
1214}
1215
1216static enum ssl_hs_wait_t do_read_certificate_request(SSL_HANDSHAKE *hs) {
1217 SSL *const ssl = hs->ssl;
1218
1219 if (!ssl_cipher_uses_certificate_auth(cipher: hs->new_cipher)) {
1220 hs->state = state_read_server_hello_done;
1221 return ssl_hs_ok;
1222 }
1223
1224 SSLMessage msg;
1225 if (!ssl->method->get_message(ssl, &msg)) {
1226 return ssl_hs_read_message;
1227 }
1228
1229 if (msg.type == SSL3_MT_SERVER_HELLO_DONE) {
1230 // If we get here we don't need the handshake buffer as we won't be doing
1231 // client auth.
1232 hs->transcript.FreeBuffer();
1233 hs->state = state_read_server_hello_done;
1234 return ssl_hs_ok;
1235 }
1236
1237 if (!ssl_check_message_type(ssl, msg, SSL3_MT_CERTIFICATE_REQUEST) ||
1238 !ssl_hash_message(hs, msg)) {
1239 return ssl_hs_error;
1240 }
1241
1242 // Get the certificate types.
1243 CBS body = msg.body, certificate_types;
1244 if (!CBS_get_u8_length_prefixed(cbs: &body, out: &certificate_types)) {
1245 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1246 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1247 return ssl_hs_error;
1248 }
1249
1250 if (!hs->certificate_types.CopyFrom(in: certificate_types)) {
1251 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
1252 return ssl_hs_error;
1253 }
1254
1255 if (ssl_protocol_version(ssl) >= TLS1_2_VERSION) {
1256 CBS supported_signature_algorithms;
1257 if (!CBS_get_u16_length_prefixed(cbs: &body, out: &supported_signature_algorithms) ||
1258 !tls1_parse_peer_sigalgs(hs, sigalgs: &supported_signature_algorithms)) {
1259 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1260 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1261 return ssl_hs_error;
1262 }
1263 }
1264
1265 uint8_t alert = SSL_AD_DECODE_ERROR;
1266 UniquePtr<STACK_OF(CRYPTO_BUFFER)> ca_names =
1267 ssl_parse_client_CA_list(ssl, out_alert: &alert, cbs: &body);
1268 if (!ca_names) {
1269 ssl_send_alert(ssl, SSL3_AL_FATAL, desc: alert);
1270 return ssl_hs_error;
1271 }
1272
1273 if (CBS_len(cbs: &body) != 0) {
1274 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1275 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1276 return ssl_hs_error;
1277 }
1278
1279 hs->cert_request = true;
1280 hs->ca_names = std::move(ca_names);
1281 ssl->ctx->x509_method->hs_flush_cached_ca_names(hs);
1282
1283 ssl->method->next_message(ssl);
1284 hs->state = state_read_server_hello_done;
1285 return ssl_hs_ok;
1286}
1287
1288static enum ssl_hs_wait_t do_read_server_hello_done(SSL_HANDSHAKE *hs) {
1289 SSL *const ssl = hs->ssl;
1290 SSLMessage msg;
1291 if (!ssl->method->get_message(ssl, &msg)) {
1292 return ssl_hs_read_message;
1293 }
1294
1295 if (!ssl_check_message_type(ssl, msg, SSL3_MT_SERVER_HELLO_DONE) ||
1296 !ssl_hash_message(hs, msg)) {
1297 return ssl_hs_error;
1298 }
1299
1300 // ServerHelloDone is empty.
1301 if (CBS_len(cbs: &msg.body) != 0) {
1302 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1303 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1304 return ssl_hs_error;
1305 }
1306
1307 // ServerHelloDone should be the end of the flight.
1308 if (ssl->method->has_unprocessed_handshake_data(ssl)) {
1309 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
1310 OPENSSL_PUT_ERROR(SSL, SSL_R_EXCESS_HANDSHAKE_DATA);
1311 return ssl_hs_error;
1312 }
1313
1314 ssl->method->next_message(ssl);
1315 hs->state = state_send_client_certificate;
1316 return ssl_hs_ok;
1317}
1318
1319static enum ssl_hs_wait_t do_send_client_certificate(SSL_HANDSHAKE *hs) {
1320 SSL *const ssl = hs->ssl;
1321
1322 // The peer didn't request a certificate.
1323 if (!hs->cert_request) {
1324 hs->state = state_send_client_key_exchange;
1325 return ssl_hs_ok;
1326 }
1327
1328 if (ssl->s3->ech_status == ssl_ech_rejected) {
1329 // Do not send client certificates on ECH reject. We have not authenticated
1330 // the server for the name that can learn the certificate.
1331 SSL_certs_clear(ssl);
1332 } else if (hs->config->cert->cert_cb != nullptr) {
1333 // Call cert_cb to update the certificate.
1334 int rv = hs->config->cert->cert_cb(ssl, hs->config->cert->cert_cb_arg);
1335 if (rv == 0) {
1336 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
1337 OPENSSL_PUT_ERROR(SSL, SSL_R_CERT_CB_ERROR);
1338 return ssl_hs_error;
1339 }
1340 if (rv < 0) {
1341 hs->state = state_send_client_certificate;
1342 return ssl_hs_x509_lookup;
1343 }
1344 }
1345
1346 if (!ssl_has_certificate(hs)) {
1347 // Without a client certificate, the handshake buffer may be released.
1348 hs->transcript.FreeBuffer();
1349 }
1350
1351 if (!ssl_on_certificate_selected(hs) ||
1352 !ssl_output_cert_chain(hs)) {
1353 return ssl_hs_error;
1354 }
1355
1356
1357 hs->state = state_send_client_key_exchange;
1358 return ssl_hs_ok;
1359}
1360
1361static_assert(sizeof(size_t) >= sizeof(unsigned),
1362 "size_t is smaller than unsigned");
1363
1364static enum ssl_hs_wait_t do_send_client_key_exchange(SSL_HANDSHAKE *hs) {
1365 SSL *const ssl = hs->ssl;
1366 ScopedCBB cbb;
1367 CBB body;
1368 if (!ssl->method->init_message(ssl, cbb.get(), &body,
1369 SSL3_MT_CLIENT_KEY_EXCHANGE)) {
1370 return ssl_hs_error;
1371 }
1372
1373 Array<uint8_t> pms;
1374 uint32_t alg_k = hs->new_cipher->algorithm_mkey;
1375 uint32_t alg_a = hs->new_cipher->algorithm_auth;
1376 if (ssl_cipher_uses_certificate_auth(cipher: hs->new_cipher)) {
1377 const CRYPTO_BUFFER *leaf =
1378 sk_CRYPTO_BUFFER_value(sk: hs->new_session->certs.get(), i: 0);
1379 CBS leaf_cbs;
1380 CRYPTO_BUFFER_init_CBS(buf: leaf, out: &leaf_cbs);
1381
1382 // Check the key usage matches the cipher suite. We do this unconditionally
1383 // for non-RSA certificates. In particular, it's needed to distinguish ECDH
1384 // certificates, which we do not support, from ECDSA certificates.
1385 // Historically, we have not checked RSA key usages, so it is controlled by
1386 // a flag for now. See https://crbug.com/795089.
1387 ssl_key_usage_t intended_use = (alg_k & SSL_kRSA)
1388 ? key_usage_encipherment
1389 : key_usage_digital_signature;
1390 if (!ssl_cert_check_key_usage(in: &leaf_cbs, bit: intended_use)) {
1391 if (hs->config->enforce_rsa_key_usage ||
1392 EVP_PKEY_id(pkey: hs->peer_pubkey.get()) != EVP_PKEY_RSA) {
1393 return ssl_hs_error;
1394 }
1395 ERR_clear_error();
1396 ssl->s3->was_key_usage_invalid = true;
1397 }
1398 }
1399
1400 // If using a PSK key exchange, prepare the pre-shared key.
1401 unsigned psk_len = 0;
1402 uint8_t psk[PSK_MAX_PSK_LEN];
1403 if (alg_a & SSL_aPSK) {
1404 if (hs->config->psk_client_callback == NULL) {
1405 OPENSSL_PUT_ERROR(SSL, SSL_R_PSK_NO_CLIENT_CB);
1406 return ssl_hs_error;
1407 }
1408
1409 char identity[PSK_MAX_IDENTITY_LEN + 1];
1410 OPENSSL_memset(dst: identity, c: 0, n: sizeof(identity));
1411 psk_len = hs->config->psk_client_callback(
1412 ssl, hs->peer_psk_identity_hint.get(), identity, sizeof(identity), psk,
1413 sizeof(psk));
1414 if (psk_len == 0) {
1415 OPENSSL_PUT_ERROR(SSL, SSL_R_PSK_IDENTITY_NOT_FOUND);
1416 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
1417 return ssl_hs_error;
1418 }
1419 assert(psk_len <= PSK_MAX_PSK_LEN);
1420
1421 hs->new_session->psk_identity.reset(p: OPENSSL_strdup(s: identity));
1422 if (hs->new_session->psk_identity == nullptr) {
1423 return ssl_hs_error;
1424 }
1425
1426 // Write out psk_identity.
1427 CBB child;
1428 if (!CBB_add_u16_length_prefixed(cbb: &body, out_contents: &child) ||
1429 !CBB_add_bytes(cbb: &child, data: (const uint8_t *)identity,
1430 len: OPENSSL_strnlen(s: identity, len: sizeof(identity))) ||
1431 !CBB_flush(cbb: &body)) {
1432 return ssl_hs_error;
1433 }
1434 }
1435
1436 // Depending on the key exchange method, compute |pms|.
1437 if (alg_k & SSL_kRSA) {
1438 if (!pms.Init(SSL_MAX_MASTER_KEY_LENGTH)) {
1439 return ssl_hs_error;
1440 }
1441
1442 RSA *rsa = EVP_PKEY_get0_RSA(pkey: hs->peer_pubkey.get());
1443 if (rsa == NULL) {
1444 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
1445 return ssl_hs_error;
1446 }
1447
1448 pms[0] = hs->client_version >> 8;
1449 pms[1] = hs->client_version & 0xff;
1450 if (!RAND_bytes(buf: &pms[2], SSL_MAX_MASTER_KEY_LENGTH - 2)) {
1451 return ssl_hs_error;
1452 }
1453
1454 CBB enc_pms;
1455 uint8_t *ptr;
1456 size_t enc_pms_len;
1457 if (!CBB_add_u16_length_prefixed(cbb: &body, out_contents: &enc_pms) ||
1458 !CBB_reserve(cbb: &enc_pms, out_data: &ptr, len: RSA_size(rsa)) ||
1459 !RSA_encrypt(rsa, out_len: &enc_pms_len, out: ptr, max_out: RSA_size(rsa), in: pms.data(),
1460 in_len: pms.size(), RSA_PKCS1_PADDING) ||
1461 !CBB_did_write(cbb: &enc_pms, len: enc_pms_len) ||
1462 !CBB_flush(cbb: &body)) {
1463 return ssl_hs_error;
1464 }
1465 } else if (alg_k & SSL_kECDHE) {
1466 CBB child;
1467 if (!CBB_add_u8_length_prefixed(cbb: &body, out_contents: &child)) {
1468 return ssl_hs_error;
1469 }
1470
1471 // Generate a premaster secret and encapsulate it.
1472 bssl::UniquePtr<SSLKeyShare> kem =
1473 SSLKeyShare::Create(group_id: hs->new_session->group_id);
1474 uint8_t alert = SSL_AD_DECODE_ERROR;
1475 if (!kem || !kem->Encap(out_ciphertext: &child, out_secret: &pms, out_alert: &alert, peer_key: hs->peer_key)) {
1476 ssl_send_alert(ssl, SSL3_AL_FATAL, desc: alert);
1477 return ssl_hs_error;
1478 }
1479 if (!CBB_flush(cbb: &body)) {
1480 return ssl_hs_error;
1481 }
1482
1483 // The peer key can now be discarded.
1484 hs->peer_key.Reset();
1485 } else if (alg_k & SSL_kPSK) {
1486 // For plain PSK, other_secret is a block of 0s with the same length as
1487 // the pre-shared key.
1488 if (!pms.Init(new_size: psk_len)) {
1489 return ssl_hs_error;
1490 }
1491 OPENSSL_memset(dst: pms.data(), c: 0, n: pms.size());
1492 } else {
1493 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
1494 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
1495 return ssl_hs_error;
1496 }
1497
1498 // For a PSK cipher suite, other_secret is combined with the pre-shared
1499 // key.
1500 if (alg_a & SSL_aPSK) {
1501 ScopedCBB pms_cbb;
1502 CBB child;
1503 if (!CBB_init(cbb: pms_cbb.get(), initial_capacity: 2 + psk_len + 2 + pms.size()) ||
1504 !CBB_add_u16_length_prefixed(cbb: pms_cbb.get(), out_contents: &child) ||
1505 !CBB_add_bytes(cbb: &child, data: pms.data(), len: pms.size()) ||
1506 !CBB_add_u16_length_prefixed(cbb: pms_cbb.get(), out_contents: &child) ||
1507 !CBB_add_bytes(cbb: &child, data: psk, len: psk_len) ||
1508 !CBBFinishArray(cbb: pms_cbb.get(), out: &pms)) {
1509 return ssl_hs_error;
1510 }
1511 }
1512
1513 // The message must be added to the finished hash before calculating the
1514 // master secret.
1515 if (!ssl_add_message_cbb(ssl, cbb: cbb.get())) {
1516 return ssl_hs_error;
1517 }
1518
1519 hs->new_session->secret_length =
1520 tls1_generate_master_secret(hs, out: hs->new_session->secret, premaster: pms);
1521 if (hs->new_session->secret_length == 0) {
1522 return ssl_hs_error;
1523 }
1524 hs->new_session->extended_master_secret = hs->extended_master_secret;
1525
1526 hs->state = state_send_client_certificate_verify;
1527 return ssl_hs_ok;
1528}
1529
1530static enum ssl_hs_wait_t do_send_client_certificate_verify(SSL_HANDSHAKE *hs) {
1531 SSL *const ssl = hs->ssl;
1532
1533 if (!hs->cert_request || !ssl_has_certificate(hs)) {
1534 hs->state = state_send_client_finished;
1535 return ssl_hs_ok;
1536 }
1537
1538 assert(ssl_has_private_key(hs));
1539 ScopedCBB cbb;
1540 CBB body, child;
1541 if (!ssl->method->init_message(ssl, cbb.get(), &body,
1542 SSL3_MT_CERTIFICATE_VERIFY)) {
1543 return ssl_hs_error;
1544 }
1545
1546 uint16_t signature_algorithm;
1547 if (!tls1_choose_signature_algorithm(hs, out: &signature_algorithm)) {
1548 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
1549 return ssl_hs_error;
1550 }
1551 if (ssl_protocol_version(ssl) >= TLS1_2_VERSION) {
1552 // Write out the digest type in TLS 1.2.
1553 if (!CBB_add_u16(cbb: &body, value: signature_algorithm)) {
1554 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
1555 return ssl_hs_error;
1556 }
1557 }
1558
1559 // Set aside space for the signature.
1560 const size_t max_sig_len = EVP_PKEY_size(pkey: hs->local_pubkey.get());
1561 uint8_t *ptr;
1562 if (!CBB_add_u16_length_prefixed(cbb: &body, out_contents: &child) ||
1563 !CBB_reserve(cbb: &child, out_data: &ptr, len: max_sig_len)) {
1564 return ssl_hs_error;
1565 }
1566
1567 size_t sig_len = max_sig_len;
1568 switch (ssl_private_key_sign(hs, out: ptr, out_len: &sig_len, max_out: max_sig_len,
1569 sigalg: signature_algorithm,
1570 in: hs->transcript.buffer())) {
1571 case ssl_private_key_success:
1572 break;
1573 case ssl_private_key_failure:
1574 return ssl_hs_error;
1575 case ssl_private_key_retry:
1576 hs->state = state_send_client_certificate_verify;
1577 return ssl_hs_private_key_operation;
1578 }
1579
1580 if (!CBB_did_write(cbb: &child, len: sig_len) ||
1581 !ssl_add_message_cbb(ssl, cbb: cbb.get())) {
1582 return ssl_hs_error;
1583 }
1584
1585 // The handshake buffer is no longer necessary.
1586 hs->transcript.FreeBuffer();
1587
1588 hs->state = state_send_client_finished;
1589 return ssl_hs_ok;
1590}
1591
1592static enum ssl_hs_wait_t do_send_client_finished(SSL_HANDSHAKE *hs) {
1593 SSL *const ssl = hs->ssl;
1594 hs->can_release_private_key = true;
1595 if (!ssl->method->add_change_cipher_spec(ssl) ||
1596 !tls1_change_cipher_state(hs, direction: evp_aead_seal)) {
1597 return ssl_hs_error;
1598 }
1599
1600 if (hs->next_proto_neg_seen) {
1601 static const uint8_t kZero[32] = {0};
1602 size_t padding_len =
1603 32 - ((ssl->s3->next_proto_negotiated.size() + 2) % 32);
1604
1605 ScopedCBB cbb;
1606 CBB body, child;
1607 if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_NEXT_PROTO) ||
1608 !CBB_add_u8_length_prefixed(cbb: &body, out_contents: &child) ||
1609 !CBB_add_bytes(cbb: &child, data: ssl->s3->next_proto_negotiated.data(),
1610 len: ssl->s3->next_proto_negotiated.size()) ||
1611 !CBB_add_u8_length_prefixed(cbb: &body, out_contents: &child) ||
1612 !CBB_add_bytes(cbb: &child, data: kZero, len: padding_len) ||
1613 !ssl_add_message_cbb(ssl, cbb: cbb.get())) {
1614 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
1615 return ssl_hs_error;
1616 }
1617 }
1618
1619 if (hs->channel_id_negotiated) {
1620 ScopedCBB cbb;
1621 CBB body;
1622 if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_CHANNEL_ID) ||
1623 !tls1_write_channel_id(hs, cbb: &body) ||
1624 !ssl_add_message_cbb(ssl, cbb: cbb.get())) {
1625 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
1626 return ssl_hs_error;
1627 }
1628 }
1629
1630 if (!ssl_send_finished(hs)) {
1631 return ssl_hs_error;
1632 }
1633
1634 hs->state = state_finish_flight;
1635 return ssl_hs_flush;
1636}
1637
1638static bool can_false_start(const SSL_HANDSHAKE *hs) {
1639 const SSL *const ssl = hs->ssl;
1640
1641 // False Start bypasses the Finished check's downgrade protection. This can
1642 // enable attacks where we send data under weaker settings than supported
1643 // (e.g. the Logjam attack). Thus we require TLS 1.2 with an ECDHE+AEAD
1644 // cipher, our strongest settings before TLS 1.3.
1645 //
1646 // Now that TLS 1.3 exists, we would like to avoid similar attacks between
1647 // TLS 1.2 and TLS 1.3, but there are too many TLS 1.2 deployments to
1648 // sacrifice False Start on them. Instead, we rely on the ServerHello.random
1649 // downgrade signal, which we unconditionally enforce.
1650 if (SSL_is_dtls(ssl) ||
1651 SSL_version(ssl) != TLS1_2_VERSION ||
1652 hs->new_cipher->algorithm_mkey != SSL_kECDHE ||
1653 hs->new_cipher->algorithm_mac != SSL_AEAD) {
1654 return false;
1655 }
1656
1657 // If ECH was rejected, disable False Start. We run the handshake to
1658 // completion, including the Finished downgrade check, to authenticate the
1659 // recovery flow.
1660 if (ssl->s3->ech_status == ssl_ech_rejected) {
1661 return false;
1662 }
1663
1664 // Additionally require ALPN or NPN by default.
1665 //
1666 // TODO(davidben): Can this constraint be relaxed globally now that cipher
1667 // suite requirements have been tightened?
1668 if (!ssl->ctx->false_start_allowed_without_alpn &&
1669 ssl->s3->alpn_selected.empty() &&
1670 ssl->s3->next_proto_negotiated.empty()) {
1671 return false;
1672 }
1673
1674 return true;
1675}
1676
1677static enum ssl_hs_wait_t do_finish_flight(SSL_HANDSHAKE *hs) {
1678 SSL *const ssl = hs->ssl;
1679 if (ssl->session != NULL) {
1680 hs->state = state_finish_client_handshake;
1681 return ssl_hs_ok;
1682 }
1683
1684 // This is a full handshake. If it involves ChannelID, then record the
1685 // handshake hashes at this point in the session so that any resumption of
1686 // this session with ChannelID can sign those hashes.
1687 if (!tls1_record_handshake_hashes_for_channel_id(hs)) {
1688 return ssl_hs_error;
1689 }
1690
1691 hs->state = state_read_session_ticket;
1692
1693 if ((SSL_get_mode(ssl) & SSL_MODE_ENABLE_FALSE_START) &&
1694 can_false_start(hs) &&
1695 // No False Start on renegotiation (would complicate the state machine).
1696 !ssl->s3->initial_handshake_complete) {
1697 hs->in_false_start = true;
1698 hs->can_early_write = true;
1699 return ssl_hs_early_return;
1700 }
1701
1702 return ssl_hs_ok;
1703}
1704
1705static enum ssl_hs_wait_t do_read_session_ticket(SSL_HANDSHAKE *hs) {
1706 SSL *const ssl = hs->ssl;
1707
1708 if (!hs->ticket_expected) {
1709 hs->state = state_process_change_cipher_spec;
1710 return ssl_hs_read_change_cipher_spec;
1711 }
1712
1713 SSLMessage msg;
1714 if (!ssl->method->get_message(ssl, &msg)) {
1715 return ssl_hs_read_message;
1716 }
1717
1718 if (!ssl_check_message_type(ssl, msg, SSL3_MT_NEW_SESSION_TICKET) ||
1719 !ssl_hash_message(hs, msg)) {
1720 return ssl_hs_error;
1721 }
1722
1723 CBS new_session_ticket = msg.body, ticket;
1724 uint32_t ticket_lifetime_hint;
1725 if (!CBS_get_u32(cbs: &new_session_ticket, out: &ticket_lifetime_hint) ||
1726 !CBS_get_u16_length_prefixed(cbs: &new_session_ticket, out: &ticket) ||
1727 CBS_len(cbs: &new_session_ticket) != 0) {
1728 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1729 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1730 return ssl_hs_error;
1731 }
1732
1733 if (CBS_len(cbs: &ticket) == 0) {
1734 // RFC 5077 allows a server to change its mind and send no ticket after
1735 // negotiating the extension. The value of |ticket_expected| is checked in
1736 // |ssl_update_cache| so is cleared here to avoid an unnecessary update.
1737 hs->ticket_expected = false;
1738 ssl->method->next_message(ssl);
1739 hs->state = state_process_change_cipher_spec;
1740 return ssl_hs_read_change_cipher_spec;
1741 }
1742
1743 if (ssl->session != nullptr) {
1744 // The server is sending a new ticket for an existing session. Sessions are
1745 // immutable once established, so duplicate all but the ticket of the
1746 // existing session.
1747 assert(!hs->new_session);
1748 hs->new_session =
1749 SSL_SESSION_dup(session: ssl->session.get(), SSL_SESSION_INCLUDE_NONAUTH);
1750 if (!hs->new_session) {
1751 return ssl_hs_error;
1752 }
1753 }
1754
1755 // |ticket_lifetime_hint| is measured from when the ticket was issued.
1756 ssl_session_rebase_time(ssl, session: hs->new_session.get());
1757
1758 if (!hs->new_session->ticket.CopyFrom(in: ticket)) {
1759 return ssl_hs_error;
1760 }
1761 hs->new_session->ticket_lifetime_hint = ticket_lifetime_hint;
1762
1763 // Historically, OpenSSL filled in fake session IDs for ticket-based sessions.
1764 // TODO(davidben): Are external callers relying on this? Try removing this.
1765 SHA256(data: CBS_data(cbs: &ticket), len: CBS_len(cbs: &ticket), out: hs->new_session->session_id);
1766 hs->new_session->session_id_length = SHA256_DIGEST_LENGTH;
1767
1768 ssl->method->next_message(ssl);
1769 hs->state = state_process_change_cipher_spec;
1770 return ssl_hs_read_change_cipher_spec;
1771}
1772
1773static enum ssl_hs_wait_t do_process_change_cipher_spec(SSL_HANDSHAKE *hs) {
1774 if (!tls1_change_cipher_state(hs, direction: evp_aead_open)) {
1775 return ssl_hs_error;
1776 }
1777
1778 hs->state = state_read_server_finished;
1779 return ssl_hs_ok;
1780}
1781
1782static enum ssl_hs_wait_t do_read_server_finished(SSL_HANDSHAKE *hs) {
1783 SSL *const ssl = hs->ssl;
1784 enum ssl_hs_wait_t wait = ssl_get_finished(hs);
1785 if (wait != ssl_hs_ok) {
1786 return wait;
1787 }
1788
1789 if (ssl->session != NULL) {
1790 hs->state = state_send_client_finished;
1791 return ssl_hs_ok;
1792 }
1793
1794 hs->state = state_finish_client_handshake;
1795 return ssl_hs_ok;
1796}
1797
1798static enum ssl_hs_wait_t do_finish_client_handshake(SSL_HANDSHAKE *hs) {
1799 SSL *const ssl = hs->ssl;
1800 if (ssl->s3->ech_status == ssl_ech_rejected) {
1801 // Release the retry configs.
1802 hs->ech_authenticated_reject = true;
1803 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ECH_REQUIRED);
1804 OPENSSL_PUT_ERROR(SSL, SSL_R_ECH_REJECTED);
1805 return ssl_hs_error;
1806 }
1807
1808 ssl->method->on_handshake_complete(ssl);
1809
1810 // Note TLS 1.2 resumptions with ticket renewal have both |ssl->session| (the
1811 // resumed session) and |hs->new_session| (the session with the new ticket).
1812 bool has_new_session = hs->new_session != nullptr;
1813 if (has_new_session) {
1814 // When False Start is enabled, the handshake reports completion early. The
1815 // caller may then have passed the (then unresuable) |hs->new_session| to
1816 // another thread via |SSL_get0_session| for resumption. To avoid potential
1817 // race conditions in such callers, we duplicate the session before
1818 // clearing |not_resumable|.
1819 ssl->s3->established_session =
1820 SSL_SESSION_dup(session: hs->new_session.get(), SSL_SESSION_DUP_ALL);
1821 if (!ssl->s3->established_session) {
1822 return ssl_hs_error;
1823 }
1824 // Renegotiations do not participate in session resumption.
1825 if (!ssl->s3->initial_handshake_complete) {
1826 ssl->s3->established_session->not_resumable = false;
1827 }
1828
1829 hs->new_session.reset();
1830 } else {
1831 assert(ssl->session != nullptr);
1832 ssl->s3->established_session = UpRef(ptr: ssl->session);
1833 }
1834
1835 hs->handshake_finalized = true;
1836 ssl->s3->initial_handshake_complete = true;
1837 if (has_new_session) {
1838 ssl_update_cache(ssl);
1839 }
1840
1841 hs->state = state_done;
1842 return ssl_hs_ok;
1843}
1844
1845enum ssl_hs_wait_t ssl_client_handshake(SSL_HANDSHAKE *hs) {
1846 while (hs->state != state_done) {
1847 enum ssl_hs_wait_t ret = ssl_hs_error;
1848 enum ssl_client_hs_state_t state =
1849 static_cast<enum ssl_client_hs_state_t>(hs->state);
1850 switch (state) {
1851 case state_start_connect:
1852 ret = do_start_connect(hs);
1853 break;
1854 case state_enter_early_data:
1855 ret = do_enter_early_data(hs);
1856 break;
1857 case state_early_reverify_server_certificate:
1858 ret = do_early_reverify_server_certificate(hs);
1859 break;
1860 case state_read_hello_verify_request:
1861 ret = do_read_hello_verify_request(hs);
1862 break;
1863 case state_read_server_hello:
1864 ret = do_read_server_hello(hs);
1865 break;
1866 case state_tls13:
1867 ret = do_tls13(hs);
1868 break;
1869 case state_read_server_certificate:
1870 ret = do_read_server_certificate(hs);
1871 break;
1872 case state_read_certificate_status:
1873 ret = do_read_certificate_status(hs);
1874 break;
1875 case state_verify_server_certificate:
1876 ret = do_verify_server_certificate(hs);
1877 break;
1878 case state_reverify_server_certificate:
1879 ret = do_reverify_server_certificate(hs);
1880 break;
1881 case state_read_server_key_exchange:
1882 ret = do_read_server_key_exchange(hs);
1883 break;
1884 case state_read_certificate_request:
1885 ret = do_read_certificate_request(hs);
1886 break;
1887 case state_read_server_hello_done:
1888 ret = do_read_server_hello_done(hs);
1889 break;
1890 case state_send_client_certificate:
1891 ret = do_send_client_certificate(hs);
1892 break;
1893 case state_send_client_key_exchange:
1894 ret = do_send_client_key_exchange(hs);
1895 break;
1896 case state_send_client_certificate_verify:
1897 ret = do_send_client_certificate_verify(hs);
1898 break;
1899 case state_send_client_finished:
1900 ret = do_send_client_finished(hs);
1901 break;
1902 case state_finish_flight:
1903 ret = do_finish_flight(hs);
1904 break;
1905 case state_read_session_ticket:
1906 ret = do_read_session_ticket(hs);
1907 break;
1908 case state_process_change_cipher_spec:
1909 ret = do_process_change_cipher_spec(hs);
1910 break;
1911 case state_read_server_finished:
1912 ret = do_read_server_finished(hs);
1913 break;
1914 case state_finish_client_handshake:
1915 ret = do_finish_client_handshake(hs);
1916 break;
1917 case state_done:
1918 ret = ssl_hs_ok;
1919 break;
1920 }
1921
1922 if (hs->state != state) {
1923 ssl_do_info_callback(ssl: hs->ssl, SSL_CB_CONNECT_LOOP, value: 1);
1924 }
1925
1926 if (ret != ssl_hs_ok) {
1927 return ret;
1928 }
1929 }
1930
1931 ssl_do_info_callback(ssl: hs->ssl, SSL_CB_HANDSHAKE_DONE, value: 1);
1932 return ssl_hs_ok;
1933}
1934
1935const char *ssl_client_handshake_state(SSL_HANDSHAKE *hs) {
1936 enum ssl_client_hs_state_t state =
1937 static_cast<enum ssl_client_hs_state_t>(hs->state);
1938 switch (state) {
1939 case state_start_connect:
1940 return "TLS client start_connect";
1941 case state_enter_early_data:
1942 return "TLS client enter_early_data";
1943 case state_early_reverify_server_certificate:
1944 return "TLS client early_reverify_server_certificate";
1945 case state_read_hello_verify_request:
1946 return "TLS client read_hello_verify_request";
1947 case state_read_server_hello:
1948 return "TLS client read_server_hello";
1949 case state_tls13:
1950 return tls13_client_handshake_state(hs);
1951 case state_read_server_certificate:
1952 return "TLS client read_server_certificate";
1953 case state_read_certificate_status:
1954 return "TLS client read_certificate_status";
1955 case state_verify_server_certificate:
1956 return "TLS client verify_server_certificate";
1957 case state_reverify_server_certificate:
1958 return "TLS client reverify_server_certificate";
1959 case state_read_server_key_exchange:
1960 return "TLS client read_server_key_exchange";
1961 case state_read_certificate_request:
1962 return "TLS client read_certificate_request";
1963 case state_read_server_hello_done:
1964 return "TLS client read_server_hello_done";
1965 case state_send_client_certificate:
1966 return "TLS client send_client_certificate";
1967 case state_send_client_key_exchange:
1968 return "TLS client send_client_key_exchange";
1969 case state_send_client_certificate_verify:
1970 return "TLS client send_client_certificate_verify";
1971 case state_send_client_finished:
1972 return "TLS client send_client_finished";
1973 case state_finish_flight:
1974 return "TLS client finish_flight";
1975 case state_read_session_ticket:
1976 return "TLS client read_session_ticket";
1977 case state_process_change_cipher_spec:
1978 return "TLS client process_change_cipher_spec";
1979 case state_read_server_finished:
1980 return "TLS client read_server_finished";
1981 case state_finish_client_handshake:
1982 return "TLS client finish_client_handshake";
1983 case state_done:
1984 return "TLS client done";
1985 }
1986
1987 return "TLS client unknown";
1988}
1989
1990BSSL_NAMESPACE_END
1991

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