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/md5.h>
166 #include <openssl/mem.h>
167 #include <openssl/rand.h>
168 #include <openssl/sha.h>
169
170 #include "../crypto/internal.h"
171 #include "internal.h"
172
173
174 BSSL_NAMESPACE_BEGIN
175
176 enum ssl_client_hs_state_t {
177 state_start_connect = 0,
178 state_enter_early_data,
179 state_early_reverify_server_certificate,
180 state_read_hello_verify_request,
181 state_read_server_hello,
182 state_tls13,
183 state_read_server_certificate,
184 state_read_certificate_status,
185 state_verify_server_certificate,
186 state_reverify_server_certificate,
187 state_read_server_key_exchange,
188 state_read_certificate_request,
189 state_read_server_hello_done,
190 state_send_client_certificate,
191 state_send_client_key_exchange,
192 state_send_client_certificate_verify,
193 state_send_client_finished,
194 state_finish_flight,
195 state_read_session_ticket,
196 state_process_change_cipher_spec,
197 state_read_server_finished,
198 state_finish_client_handshake,
199 state_done,
200 };
201
202 // ssl_get_client_disabled sets |*out_mask_a| and |*out_mask_k| to masks of
203 // disabled algorithms.
ssl_get_client_disabled(SSL_HANDSHAKE * hs,uint32_t * out_mask_a,uint32_t * out_mask_k)204 static void ssl_get_client_disabled(SSL_HANDSHAKE *hs, uint32_t *out_mask_a,
205 uint32_t *out_mask_k) {
206 *out_mask_a = 0;
207 *out_mask_k = 0;
208
209 // PSK requires a client callback.
210 if (hs->config->psk_client_callback == NULL) {
211 *out_mask_a |= SSL_aPSK;
212 *out_mask_k |= SSL_kPSK;
213 }
214 }
215
ssl_write_client_cipher_list(SSL_HANDSHAKE * hs,CBB * out)216 static bool ssl_write_client_cipher_list(SSL_HANDSHAKE *hs, CBB *out) {
217 SSL *const ssl = hs->ssl;
218 uint32_t mask_a, mask_k;
219 ssl_get_client_disabled(hs, &mask_a, &mask_k);
220
221 CBB child;
222 if (!CBB_add_u16_length_prefixed(out, &child)) {
223 return false;
224 }
225
226 // Add a fake cipher suite. See draft-davidben-tls-grease-01.
227 if (ssl->ctx->grease_enabled &&
228 !CBB_add_u16(&child, ssl_get_grease_value(hs, ssl_grease_cipher))) {
229 return false;
230 }
231
232 // Add TLS 1.3 ciphers. Order ChaCha20-Poly1305 relative to AES-GCM based on
233 // hardware support.
234 if (hs->max_version >= TLS1_3_VERSION) {
235 if (!EVP_has_aes_hardware() &&
236 !CBB_add_u16(&child, TLS1_CK_CHACHA20_POLY1305_SHA256 & 0xffff)) {
237 return false;
238 }
239 if (!CBB_add_u16(&child, TLS1_CK_AES_128_GCM_SHA256 & 0xffff) ||
240 !CBB_add_u16(&child, TLS1_CK_AES_256_GCM_SHA384 & 0xffff)) {
241 return false;
242 }
243 if (EVP_has_aes_hardware() &&
244 !CBB_add_u16(&child, TLS1_CK_CHACHA20_POLY1305_SHA256 & 0xffff)) {
245 return false;
246 }
247 }
248
249 if (hs->min_version < TLS1_3_VERSION) {
250 bool any_enabled = false;
251 for (const SSL_CIPHER *cipher : SSL_get_ciphers(ssl)) {
252 // Skip disabled ciphers
253 if ((cipher->algorithm_mkey & mask_k) ||
254 (cipher->algorithm_auth & mask_a)) {
255 continue;
256 }
257 if (SSL_CIPHER_get_min_version(cipher) > hs->max_version ||
258 SSL_CIPHER_get_max_version(cipher) < hs->min_version) {
259 continue;
260 }
261 any_enabled = true;
262 if (!CBB_add_u16(&child, SSL_CIPHER_get_protocol_id(cipher))) {
263 return false;
264 }
265 }
266
267 // If all ciphers were disabled, return the error to the caller.
268 if (!any_enabled && hs->max_version < TLS1_3_VERSION) {
269 OPENSSL_PUT_ERROR(SSL, SSL_R_NO_CIPHERS_AVAILABLE);
270 return false;
271 }
272 }
273
274 if (ssl->mode & SSL_MODE_SEND_FALLBACK_SCSV) {
275 if (!CBB_add_u16(&child, SSL3_CK_FALLBACK_SCSV & 0xffff)) {
276 return false;
277 }
278 }
279
280 return CBB_flush(out);
281 }
282
ssl_write_client_hello(SSL_HANDSHAKE * hs)283 bool ssl_write_client_hello(SSL_HANDSHAKE *hs) {
284 SSL *const ssl = hs->ssl;
285 ScopedCBB cbb;
286 CBB body;
287 if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_CLIENT_HELLO)) {
288 return false;
289 }
290
291 CBB child;
292 if (!CBB_add_u16(&body, hs->client_version) ||
293 !CBB_add_bytes(&body, ssl->s3->client_random, SSL3_RANDOM_SIZE) ||
294 !CBB_add_u8_length_prefixed(&body, &child)) {
295 return false;
296 }
297
298 // Do not send a session ID on renegotiation.
299 if (!ssl->s3->initial_handshake_complete &&
300 !CBB_add_bytes(&child, hs->session_id, hs->session_id_len)) {
301 return false;
302 }
303
304 if (SSL_is_dtls(ssl)) {
305 if (!CBB_add_u8_length_prefixed(&body, &child) ||
306 !CBB_add_bytes(&child, ssl->d1->cookie, ssl->d1->cookie_len)) {
307 return false;
308 }
309 }
310
311 size_t header_len =
312 SSL_is_dtls(ssl) ? DTLS1_HM_HEADER_LENGTH : SSL3_HM_HEADER_LENGTH;
313 if (!ssl_write_client_cipher_list(hs, &body) ||
314 !CBB_add_u8(&body, 1 /* one compression method */) ||
315 !CBB_add_u8(&body, 0 /* null compression */) ||
316 !ssl_add_clienthello_tlsext(hs, &body, header_len + CBB_len(&body))) {
317 return false;
318 }
319
320 Array<uint8_t> msg;
321 if (!ssl->method->finish_message(ssl, cbb.get(), &msg)) {
322 return false;
323 }
324
325 // Now that the length prefixes have been computed, fill in the placeholder
326 // PSK binder.
327 if (hs->needs_psk_binder &&
328 !tls13_write_psk_binder(hs, MakeSpan(msg))) {
329 return false;
330 }
331
332 return ssl->method->add_message(ssl, std::move(msg));
333 }
334
parse_supported_versions(SSL_HANDSHAKE * hs,uint16_t * version,const CBS * in)335 static bool parse_supported_versions(SSL_HANDSHAKE *hs, uint16_t *version,
336 const CBS *in) {
337 // If the outer version is not TLS 1.2, or there is no extensions block, use
338 // the outer version.
339 if (*version != TLS1_2_VERSION || CBS_len(in) == 0) {
340 return true;
341 }
342
343 SSL *const ssl = hs->ssl;
344 CBS copy = *in, extensions;
345 if (!CBS_get_u16_length_prefixed(©, &extensions) ||
346 CBS_len(©) != 0) {
347 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
348 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
349 return false;
350 }
351
352 bool have_supported_versions;
353 CBS supported_versions;
354 const SSL_EXTENSION_TYPE ext_types[] = {
355 {TLSEXT_TYPE_supported_versions, &have_supported_versions,
356 &supported_versions},
357 };
358
359 uint8_t alert = SSL_AD_DECODE_ERROR;
360 if (!ssl_parse_extensions(&extensions, &alert, ext_types,
361 /*ignore_unknown=*/true)) {
362 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
363 return false;
364 }
365
366 // Override the outer version with the extension, if present.
367 if (have_supported_versions &&
368 (!CBS_get_u16(&supported_versions, version) ||
369 CBS_len(&supported_versions) != 0)) {
370 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
371 return false;
372 }
373
374 return true;
375 }
376
do_start_connect(SSL_HANDSHAKE * hs)377 static enum ssl_hs_wait_t do_start_connect(SSL_HANDSHAKE *hs) {
378 SSL *const ssl = hs->ssl;
379
380 ssl_do_info_callback(ssl, SSL_CB_HANDSHAKE_START, 1);
381 // |session_reused| must be reset in case this is a renegotiation.
382 ssl->s3->session_reused = false;
383
384 // Freeze the version range.
385 if (!ssl_get_version_range(hs, &hs->min_version, &hs->max_version)) {
386 return ssl_hs_error;
387 }
388
389 // Always advertise the ClientHello version from the original maximum version,
390 // even on renegotiation. The static RSA key exchange uses this field, and
391 // some servers fail when it changes across handshakes.
392 if (SSL_is_dtls(hs->ssl)) {
393 hs->client_version =
394 hs->max_version >= TLS1_2_VERSION ? DTLS1_2_VERSION : DTLS1_VERSION;
395 } else {
396 hs->client_version =
397 hs->max_version >= TLS1_2_VERSION ? TLS1_2_VERSION : hs->max_version;
398 }
399
400 // If the configured session has expired or was created at a disabled
401 // version, drop it.
402 if (ssl->session != NULL) {
403 if (ssl->session->is_server ||
404 !ssl_supports_version(hs, ssl->session->ssl_version) ||
405 (ssl->session->session_id_length == 0 &&
406 ssl->session->ticket.empty()) ||
407 ssl->session->not_resumable ||
408 !ssl_session_is_time_valid(ssl, ssl->session.get()) ||
409 (ssl->quic_method != nullptr) != ssl->session->is_quic) {
410 ssl_set_session(ssl, NULL);
411 }
412 }
413
414 if (!RAND_bytes(ssl->s3->client_random, sizeof(ssl->s3->client_random))) {
415 return ssl_hs_error;
416 }
417
418 // Never send a session ID in QUIC. QUIC uses TLS 1.3 at a minimum and
419 // disables TLS 1.3 middlebox compatibility mode.
420 if (ssl->quic_method == nullptr) {
421 if (ssl->session != nullptr && !ssl->s3->initial_handshake_complete &&
422 ssl->session->session_id_length > 0) {
423 hs->session_id_len = ssl->session->session_id_length;
424 OPENSSL_memcpy(hs->session_id, ssl->session->session_id,
425 hs->session_id_len);
426 } else if (hs->max_version >= TLS1_3_VERSION) {
427 // Initialize a random session ID.
428 hs->session_id_len = sizeof(hs->session_id);
429 if (!RAND_bytes(hs->session_id, hs->session_id_len)) {
430 return ssl_hs_error;
431 }
432 }
433 }
434
435 if (!ssl_write_client_hello(hs)) {
436 return ssl_hs_error;
437 }
438
439 hs->state = state_enter_early_data;
440 return ssl_hs_flush;
441 }
442
do_enter_early_data(SSL_HANDSHAKE * hs)443 static enum ssl_hs_wait_t do_enter_early_data(SSL_HANDSHAKE *hs) {
444 SSL *const ssl = hs->ssl;
445
446 if (SSL_is_dtls(ssl)) {
447 hs->state = state_read_hello_verify_request;
448 return ssl_hs_ok;
449 }
450
451 if (!hs->early_data_offered) {
452 hs->state = state_read_server_hello;
453 return ssl_hs_ok;
454 }
455
456 ssl->s3->aead_write_ctx->SetVersionIfNullCipher(ssl->session->ssl_version);
457 if (!ssl->method->add_change_cipher_spec(ssl)) {
458 return ssl_hs_error;
459 }
460
461 if (!tls13_init_early_key_schedule(
462 hs, MakeConstSpan(ssl->session->master_key,
463 ssl->session->master_key_length)) ||
464 !tls13_derive_early_secret(hs)) {
465 return ssl_hs_error;
466 }
467
468 // Stash the early data session, so connection properties may be queried out
469 // of it.
470 hs->early_session = UpRef(ssl->session);
471 hs->state = state_early_reverify_server_certificate;
472 return ssl_hs_ok;
473 }
474
do_early_reverify_server_certificate(SSL_HANDSHAKE * hs)475 static enum ssl_hs_wait_t do_early_reverify_server_certificate(SSL_HANDSHAKE *hs) {
476 if (hs->ssl->ctx->reverify_on_resume) {
477 // Don't send an alert on error. The alert be in early data, which the
478 // server may not accept anyway. It would also be a mismatch between QUIC
479 // and TCP because the QUIC early keys are deferred below.
480 //
481 // TODO(davidben): The client behavior should be to verify the certificate
482 // before deciding whether to offer the session and, if invalid, decline to
483 // send the session.
484 switch (ssl_reverify_peer_cert(hs, /*send_alert=*/false)) {
485 case ssl_verify_ok:
486 break;
487 case ssl_verify_invalid:
488 return ssl_hs_error;
489 case ssl_verify_retry:
490 hs->state = state_early_reverify_server_certificate;
491 return ssl_hs_certificate_verify;
492 }
493 }
494
495 // Defer releasing the 0-RTT key to after certificate reverification, so the
496 // QUIC implementation does not accidentally write data too early.
497 if (!tls13_set_traffic_key(hs->ssl, ssl_encryption_early_data, evp_aead_seal,
498 hs->early_session.get(),
499 hs->early_traffic_secret())) {
500 return ssl_hs_error;
501 }
502
503 hs->in_early_data = true;
504 hs->can_early_write = true;
505 hs->state = state_read_server_hello;
506 return ssl_hs_early_return;
507 }
508
do_read_hello_verify_request(SSL_HANDSHAKE * hs)509 static enum ssl_hs_wait_t do_read_hello_verify_request(SSL_HANDSHAKE *hs) {
510 SSL *const ssl = hs->ssl;
511
512 assert(SSL_is_dtls(ssl));
513
514 SSLMessage msg;
515 if (!ssl->method->get_message(ssl, &msg)) {
516 return ssl_hs_read_message;
517 }
518
519 if (msg.type != DTLS1_MT_HELLO_VERIFY_REQUEST) {
520 hs->state = state_read_server_hello;
521 return ssl_hs_ok;
522 }
523
524 CBS hello_verify_request = msg.body, cookie;
525 uint16_t server_version;
526 if (!CBS_get_u16(&hello_verify_request, &server_version) ||
527 !CBS_get_u8_length_prefixed(&hello_verify_request, &cookie) ||
528 CBS_len(&cookie) > sizeof(ssl->d1->cookie) ||
529 CBS_len(&hello_verify_request) != 0) {
530 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
531 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
532 return ssl_hs_error;
533 }
534
535 OPENSSL_memcpy(ssl->d1->cookie, CBS_data(&cookie), CBS_len(&cookie));
536 ssl->d1->cookie_len = CBS_len(&cookie);
537
538 ssl->method->next_message(ssl);
539
540 // DTLS resets the handshake buffer after HelloVerifyRequest.
541 if (!hs->transcript.Init()) {
542 return ssl_hs_error;
543 }
544
545 if (!ssl_write_client_hello(hs)) {
546 return ssl_hs_error;
547 }
548
549 hs->state = state_read_server_hello;
550 return ssl_hs_flush;
551 }
552
do_read_server_hello(SSL_HANDSHAKE * hs)553 static enum ssl_hs_wait_t do_read_server_hello(SSL_HANDSHAKE *hs) {
554 SSL *const ssl = hs->ssl;
555 SSLMessage msg;
556 if (!ssl->method->get_message(ssl, &msg)) {
557 return ssl_hs_read_server_hello;
558 }
559
560 if (!ssl_check_message_type(ssl, msg, SSL3_MT_SERVER_HELLO)) {
561 return ssl_hs_error;
562 }
563
564 CBS server_hello = msg.body, server_random, session_id;
565 uint16_t server_version, cipher_suite;
566 uint8_t compression_method;
567 if (!CBS_get_u16(&server_hello, &server_version) ||
568 !CBS_get_bytes(&server_hello, &server_random, SSL3_RANDOM_SIZE) ||
569 !CBS_get_u8_length_prefixed(&server_hello, &session_id) ||
570 CBS_len(&session_id) > SSL3_SESSION_ID_SIZE ||
571 !CBS_get_u16(&server_hello, &cipher_suite) ||
572 !CBS_get_u8(&server_hello, &compression_method)) {
573 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
574 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
575 return ssl_hs_error;
576 }
577
578 // Use the supported_versions extension if applicable.
579 if (!parse_supported_versions(hs, &server_version, &server_hello)) {
580 return ssl_hs_error;
581 }
582
583 if (!ssl_supports_version(hs, server_version)) {
584 OPENSSL_PUT_ERROR(SSL, SSL_R_UNSUPPORTED_PROTOCOL);
585 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_PROTOCOL_VERSION);
586 return ssl_hs_error;
587 }
588
589 assert(ssl->s3->have_version == ssl->s3->initial_handshake_complete);
590 if (!ssl->s3->have_version) {
591 ssl->version = server_version;
592 // At this point, the connection's version is known and ssl->version is
593 // fixed. Begin enforcing the record-layer version.
594 ssl->s3->have_version = true;
595 ssl->s3->aead_write_ctx->SetVersionIfNullCipher(ssl->version);
596 } else if (server_version != ssl->version) {
597 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SSL_VERSION);
598 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_PROTOCOL_VERSION);
599 return ssl_hs_error;
600 }
601
602 if (ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
603 hs->state = state_tls13;
604 return ssl_hs_ok;
605 }
606
607 // Clear some TLS 1.3 state that no longer needs to be retained.
608 hs->key_shares[0].reset();
609 hs->key_shares[1].reset();
610 hs->key_share_bytes.Reset();
611
612 // A TLS 1.2 server would not know to skip the early data we offered. Report
613 // an error code sooner. The caller may use this error code to implement the
614 // fallback described in RFC 8446 appendix D.3.
615 if (hs->early_data_offered) {
616 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_VERSION_ON_EARLY_DATA);
617 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_PROTOCOL_VERSION);
618 return ssl_hs_error;
619 }
620
621 // Copy over the server random.
622 OPENSSL_memcpy(ssl->s3->server_random, CBS_data(&server_random),
623 SSL3_RANDOM_SIZE);
624
625 // Enforce the TLS 1.3 anti-downgrade feature.
626 if (!ssl->s3->initial_handshake_complete &&
627 ssl_supports_version(hs, TLS1_3_VERSION)) {
628 static_assert(
629 sizeof(kTLS12DowngradeRandom) == sizeof(kTLS13DowngradeRandom),
630 "downgrade signals have different size");
631 static_assert(
632 sizeof(kJDK11DowngradeRandom) == sizeof(kTLS13DowngradeRandom),
633 "downgrade signals have different size");
634 auto suffix =
635 MakeConstSpan(ssl->s3->server_random, sizeof(ssl->s3->server_random))
636 .subspan(SSL3_RANDOM_SIZE - sizeof(kTLS13DowngradeRandom));
637 if (suffix == kTLS12DowngradeRandom || suffix == kTLS13DowngradeRandom ||
638 suffix == kJDK11DowngradeRandom) {
639 ssl->s3->tls13_downgrade = true;
640 if (!hs->config->ignore_tls13_downgrade) {
641 OPENSSL_PUT_ERROR(SSL, SSL_R_TLS13_DOWNGRADE);
642 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
643 return ssl_hs_error;
644 }
645 }
646 }
647
648 if (!ssl->s3->initial_handshake_complete && ssl->session != nullptr &&
649 ssl->session->session_id_length != 0 &&
650 CBS_mem_equal(&session_id, ssl->session->session_id,
651 ssl->session->session_id_length)) {
652 ssl->s3->session_reused = true;
653 } else {
654 // The server may also have echoed back the TLS 1.3 compatibility mode
655 // session ID. As we know this is not a session the server knows about, any
656 // server resuming it is in error. Reject the first connection
657 // deterministicly, rather than installing an invalid session into the
658 // session cache. https://crbug.com/796910
659 if (hs->session_id_len != 0 &&
660 CBS_mem_equal(&session_id, hs->session_id, hs->session_id_len)) {
661 OPENSSL_PUT_ERROR(SSL, SSL_R_SERVER_ECHOED_INVALID_SESSION_ID);
662 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
663 return ssl_hs_error;
664 }
665
666 // The session wasn't resumed. Create a fresh SSL_SESSION to
667 // fill out.
668 ssl_set_session(ssl, NULL);
669 if (!ssl_get_new_session(hs, 0 /* client */)) {
670 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
671 return ssl_hs_error;
672 }
673 // Note: session_id could be empty.
674 hs->new_session->session_id_length = CBS_len(&session_id);
675 OPENSSL_memcpy(hs->new_session->session_id, CBS_data(&session_id),
676 CBS_len(&session_id));
677 }
678
679 const SSL_CIPHER *cipher = SSL_get_cipher_by_value(cipher_suite);
680 if (cipher == NULL) {
681 // unknown cipher
682 OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_CIPHER_RETURNED);
683 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
684 return ssl_hs_error;
685 }
686
687 // The cipher must be allowed in the selected version and enabled.
688 uint32_t mask_a, mask_k;
689 ssl_get_client_disabled(hs, &mask_a, &mask_k);
690 if ((cipher->algorithm_mkey & mask_k) || (cipher->algorithm_auth & mask_a) ||
691 SSL_CIPHER_get_min_version(cipher) > ssl_protocol_version(ssl) ||
692 SSL_CIPHER_get_max_version(cipher) < ssl_protocol_version(ssl) ||
693 !sk_SSL_CIPHER_find(SSL_get_ciphers(ssl), NULL, cipher)) {
694 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CIPHER_RETURNED);
695 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
696 return ssl_hs_error;
697 }
698
699 if (ssl->session != NULL) {
700 if (ssl->session->ssl_version != ssl->version) {
701 OPENSSL_PUT_ERROR(SSL, SSL_R_OLD_SESSION_VERSION_NOT_RETURNED);
702 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
703 return ssl_hs_error;
704 }
705 if (ssl->session->cipher != cipher) {
706 OPENSSL_PUT_ERROR(SSL, SSL_R_OLD_SESSION_CIPHER_NOT_RETURNED);
707 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
708 return ssl_hs_error;
709 }
710 if (!ssl_session_is_context_valid(hs, ssl->session.get())) {
711 // This is actually a client application bug.
712 OPENSSL_PUT_ERROR(SSL,
713 SSL_R_ATTEMPT_TO_REUSE_SESSION_IN_DIFFERENT_CONTEXT);
714 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
715 return ssl_hs_error;
716 }
717 } else {
718 hs->new_session->cipher = cipher;
719 }
720 hs->new_cipher = cipher;
721
722 // Now that the cipher is known, initialize the handshake hash and hash the
723 // ServerHello.
724 if (!hs->transcript.InitHash(ssl_protocol_version(ssl), hs->new_cipher) ||
725 !ssl_hash_message(hs, msg)) {
726 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
727 return ssl_hs_error;
728 }
729
730 // If doing a full handshake, the server may request a client certificate
731 // which requires hashing the handshake transcript. Otherwise, the handshake
732 // buffer may be released.
733 if (ssl->session != NULL ||
734 !ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
735 hs->transcript.FreeBuffer();
736 }
737
738 // Only the NULL compression algorithm is supported.
739 if (compression_method != 0) {
740 OPENSSL_PUT_ERROR(SSL, SSL_R_UNSUPPORTED_COMPRESSION_ALGORITHM);
741 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
742 return ssl_hs_error;
743 }
744
745 // TLS extensions
746 if (!ssl_parse_serverhello_tlsext(hs, &server_hello)) {
747 OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT);
748 return ssl_hs_error;
749 }
750
751 // There should be nothing left over in the record.
752 if (CBS_len(&server_hello) != 0) {
753 // wrong packet length
754 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
755 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
756 return ssl_hs_error;
757 }
758
759 if (ssl->session != NULL &&
760 hs->extended_master_secret != ssl->session->extended_master_secret) {
761 if (ssl->session->extended_master_secret) {
762 OPENSSL_PUT_ERROR(SSL, SSL_R_RESUMED_EMS_SESSION_WITHOUT_EMS_EXTENSION);
763 } else {
764 OPENSSL_PUT_ERROR(SSL, SSL_R_RESUMED_NON_EMS_SESSION_WITH_EMS_EXTENSION);
765 }
766 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
767 return ssl_hs_error;
768 }
769
770 if (ssl->s3->token_binding_negotiated &&
771 (!hs->extended_master_secret || !ssl->s3->send_connection_binding)) {
772 OPENSSL_PUT_ERROR(SSL, SSL_R_NEGOTIATED_TB_WITHOUT_EMS_OR_RI);
773 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNSUPPORTED_EXTENSION);
774 return ssl_hs_error;
775 }
776
777 ssl->method->next_message(ssl);
778
779 if (ssl->session != NULL) {
780 if (ssl->ctx->reverify_on_resume &&
781 ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
782 hs->state = state_reverify_server_certificate;
783 } else {
784 hs->state = state_read_session_ticket;
785 }
786 return ssl_hs_ok;
787 }
788
789 hs->state = state_read_server_certificate;
790 return ssl_hs_ok;
791 }
792
do_tls13(SSL_HANDSHAKE * hs)793 static enum ssl_hs_wait_t do_tls13(SSL_HANDSHAKE *hs) {
794 enum ssl_hs_wait_t wait = tls13_client_handshake(hs);
795 if (wait == ssl_hs_ok) {
796 hs->state = state_finish_client_handshake;
797 return ssl_hs_ok;
798 }
799
800 return wait;
801 }
802
do_read_server_certificate(SSL_HANDSHAKE * hs)803 static enum ssl_hs_wait_t do_read_server_certificate(SSL_HANDSHAKE *hs) {
804 SSL *const ssl = hs->ssl;
805
806 if (!ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
807 hs->state = state_read_certificate_status;
808 return ssl_hs_ok;
809 }
810
811 SSLMessage msg;
812 if (!ssl->method->get_message(ssl, &msg)) {
813 return ssl_hs_read_message;
814 }
815
816 if (!ssl_check_message_type(ssl, msg, SSL3_MT_CERTIFICATE) ||
817 !ssl_hash_message(hs, msg)) {
818 return ssl_hs_error;
819 }
820
821 CBS body = msg.body;
822 uint8_t alert = SSL_AD_DECODE_ERROR;
823 if (!ssl_parse_cert_chain(&alert, &hs->new_session->certs, &hs->peer_pubkey,
824 NULL, &body, ssl->ctx->pool)) {
825 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
826 return ssl_hs_error;
827 }
828
829 if (sk_CRYPTO_BUFFER_num(hs->new_session->certs.get()) == 0 ||
830 CBS_len(&body) != 0 ||
831 !ssl->ctx->x509_method->session_cache_objects(hs->new_session.get())) {
832 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
833 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
834 return ssl_hs_error;
835 }
836
837 if (!ssl_check_leaf_certificate(
838 hs, hs->peer_pubkey.get(),
839 sk_CRYPTO_BUFFER_value(hs->new_session->certs.get(), 0))) {
840 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
841 return ssl_hs_error;
842 }
843
844 ssl->method->next_message(ssl);
845
846 hs->state = state_read_certificate_status;
847 return ssl_hs_ok;
848 }
849
do_read_certificate_status(SSL_HANDSHAKE * hs)850 static enum ssl_hs_wait_t do_read_certificate_status(SSL_HANDSHAKE *hs) {
851 SSL *const ssl = hs->ssl;
852
853 if (!hs->certificate_status_expected) {
854 hs->state = state_verify_server_certificate;
855 return ssl_hs_ok;
856 }
857
858 SSLMessage msg;
859 if (!ssl->method->get_message(ssl, &msg)) {
860 return ssl_hs_read_message;
861 }
862
863 if (msg.type != SSL3_MT_CERTIFICATE_STATUS) {
864 // A server may send status_request in ServerHello and then change its mind
865 // about sending CertificateStatus.
866 hs->state = state_verify_server_certificate;
867 return ssl_hs_ok;
868 }
869
870 if (!ssl_hash_message(hs, msg)) {
871 return ssl_hs_error;
872 }
873
874 CBS certificate_status = msg.body, ocsp_response;
875 uint8_t status_type;
876 if (!CBS_get_u8(&certificate_status, &status_type) ||
877 status_type != TLSEXT_STATUSTYPE_ocsp ||
878 !CBS_get_u24_length_prefixed(&certificate_status, &ocsp_response) ||
879 CBS_len(&ocsp_response) == 0 ||
880 CBS_len(&certificate_status) != 0) {
881 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
882 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
883 return ssl_hs_error;
884 }
885
886 hs->new_session->ocsp_response.reset(
887 CRYPTO_BUFFER_new_from_CBS(&ocsp_response, ssl->ctx->pool));
888 if (hs->new_session->ocsp_response == nullptr) {
889 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
890 return ssl_hs_error;
891 }
892
893 ssl->method->next_message(ssl);
894
895 hs->state = state_verify_server_certificate;
896 return ssl_hs_ok;
897 }
898
do_verify_server_certificate(SSL_HANDSHAKE * hs)899 static enum ssl_hs_wait_t do_verify_server_certificate(SSL_HANDSHAKE *hs) {
900 if (!ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
901 hs->state = state_read_server_key_exchange;
902 return ssl_hs_ok;
903 }
904
905 switch (ssl_verify_peer_cert(hs)) {
906 case ssl_verify_ok:
907 break;
908 case ssl_verify_invalid:
909 return ssl_hs_error;
910 case ssl_verify_retry:
911 hs->state = state_verify_server_certificate;
912 return ssl_hs_certificate_verify;
913 }
914
915 hs->state = state_read_server_key_exchange;
916 return ssl_hs_ok;
917 }
918
do_reverify_server_certificate(SSL_HANDSHAKE * hs)919 static enum ssl_hs_wait_t do_reverify_server_certificate(SSL_HANDSHAKE *hs) {
920 assert(hs->ssl->ctx->reverify_on_resume);
921
922 switch (ssl_reverify_peer_cert(hs, /*send_alert=*/true)) {
923 case ssl_verify_ok:
924 break;
925 case ssl_verify_invalid:
926 return ssl_hs_error;
927 case ssl_verify_retry:
928 hs->state = state_reverify_server_certificate;
929 return ssl_hs_certificate_verify;
930 }
931
932 hs->state = state_read_session_ticket;
933 return ssl_hs_ok;
934 }
935
do_read_server_key_exchange(SSL_HANDSHAKE * hs)936 static enum ssl_hs_wait_t do_read_server_key_exchange(SSL_HANDSHAKE *hs) {
937 SSL *const ssl = hs->ssl;
938 SSLMessage msg;
939 if (!ssl->method->get_message(ssl, &msg)) {
940 return ssl_hs_read_message;
941 }
942
943 if (msg.type != SSL3_MT_SERVER_KEY_EXCHANGE) {
944 // Some ciphers (pure PSK) have an optional ServerKeyExchange message.
945 if (ssl_cipher_requires_server_key_exchange(hs->new_cipher)) {
946 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);
947 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
948 return ssl_hs_error;
949 }
950
951 hs->state = state_read_certificate_request;
952 return ssl_hs_ok;
953 }
954
955 if (!ssl_hash_message(hs, msg)) {
956 return ssl_hs_error;
957 }
958
959 uint32_t alg_k = hs->new_cipher->algorithm_mkey;
960 uint32_t alg_a = hs->new_cipher->algorithm_auth;
961 CBS server_key_exchange = msg.body;
962 if (alg_a & SSL_aPSK) {
963 CBS psk_identity_hint;
964
965 // Each of the PSK key exchanges begins with a psk_identity_hint.
966 if (!CBS_get_u16_length_prefixed(&server_key_exchange,
967 &psk_identity_hint)) {
968 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
969 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
970 return ssl_hs_error;
971 }
972
973 // Store the PSK identity hint for the ClientKeyExchange. Assume that the
974 // maximum length of a PSK identity hint can be as long as the maximum
975 // length of a PSK identity. Also do not allow NULL characters; identities
976 // are saved as C strings.
977 //
978 // TODO(davidben): Should invalid hints be ignored? It's a hint rather than
979 // a specific identity.
980 if (CBS_len(&psk_identity_hint) > PSK_MAX_IDENTITY_LEN ||
981 CBS_contains_zero_byte(&psk_identity_hint)) {
982 OPENSSL_PUT_ERROR(SSL, SSL_R_DATA_LENGTH_TOO_LONG);
983 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
984 return ssl_hs_error;
985 }
986
987 // Save non-empty identity hints as a C string. Empty identity hints we
988 // treat as missing. Plain PSK makes it possible to send either no hint
989 // (omit ServerKeyExchange) or an empty hint, while ECDHE_PSK can only spell
990 // empty hint. Having different capabilities is odd, so we interpret empty
991 // and missing as identical.
992 char *raw = nullptr;
993 if (CBS_len(&psk_identity_hint) != 0 &&
994 !CBS_strdup(&psk_identity_hint, &raw)) {
995 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
996 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
997 return ssl_hs_error;
998 }
999 hs->peer_psk_identity_hint.reset(raw);
1000 }
1001
1002 if (alg_k & SSL_kECDHE) {
1003 // Parse the server parameters.
1004 uint8_t group_type;
1005 uint16_t group_id;
1006 CBS point;
1007 if (!CBS_get_u8(&server_key_exchange, &group_type) ||
1008 group_type != NAMED_CURVE_TYPE ||
1009 !CBS_get_u16(&server_key_exchange, &group_id) ||
1010 !CBS_get_u8_length_prefixed(&server_key_exchange, &point)) {
1011 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1012 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1013 return ssl_hs_error;
1014 }
1015 hs->new_session->group_id = group_id;
1016
1017 // Ensure the group is consistent with preferences.
1018 if (!tls1_check_group_id(hs, group_id)) {
1019 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CURVE);
1020 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
1021 return ssl_hs_error;
1022 }
1023
1024 // Initialize ECDH and save the peer public key for later.
1025 hs->key_shares[0] = SSLKeyShare::Create(group_id);
1026 if (!hs->key_shares[0] ||
1027 !hs->peer_key.CopyFrom(point)) {
1028 return ssl_hs_error;
1029 }
1030 } else if (!(alg_k & SSL_kPSK)) {
1031 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);
1032 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
1033 return ssl_hs_error;
1034 }
1035
1036 // At this point, |server_key_exchange| contains the signature, if any, while
1037 // |msg.body| contains the entire message. From that, derive a CBS containing
1038 // just the parameter.
1039 CBS parameter;
1040 CBS_init(¶meter, CBS_data(&msg.body),
1041 CBS_len(&msg.body) - CBS_len(&server_key_exchange));
1042
1043 // ServerKeyExchange should be signed by the server's public key.
1044 if (ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
1045 uint16_t signature_algorithm = 0;
1046 if (ssl_protocol_version(ssl) >= TLS1_2_VERSION) {
1047 if (!CBS_get_u16(&server_key_exchange, &signature_algorithm)) {
1048 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1049 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1050 return ssl_hs_error;
1051 }
1052 uint8_t alert = SSL_AD_DECODE_ERROR;
1053 if (!tls12_check_peer_sigalg(hs, &alert, signature_algorithm)) {
1054 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
1055 return ssl_hs_error;
1056 }
1057 hs->new_session->peer_signature_algorithm = signature_algorithm;
1058 } else if (!tls1_get_legacy_signature_algorithm(&signature_algorithm,
1059 hs->peer_pubkey.get())) {
1060 OPENSSL_PUT_ERROR(SSL, SSL_R_PEER_ERROR_UNSUPPORTED_CERTIFICATE_TYPE);
1061 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNSUPPORTED_CERTIFICATE);
1062 return ssl_hs_error;
1063 }
1064
1065 // The last field in |server_key_exchange| is the signature.
1066 CBS signature;
1067 if (!CBS_get_u16_length_prefixed(&server_key_exchange, &signature) ||
1068 CBS_len(&server_key_exchange) != 0) {
1069 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1070 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1071 return ssl_hs_error;
1072 }
1073
1074 ScopedCBB transcript;
1075 Array<uint8_t> transcript_data;
1076 if (!CBB_init(transcript.get(),
1077 2 * SSL3_RANDOM_SIZE + CBS_len(¶meter)) ||
1078 !CBB_add_bytes(transcript.get(), ssl->s3->client_random,
1079 SSL3_RANDOM_SIZE) ||
1080 !CBB_add_bytes(transcript.get(), ssl->s3->server_random,
1081 SSL3_RANDOM_SIZE) ||
1082 !CBB_add_bytes(transcript.get(), CBS_data(¶meter),
1083 CBS_len(¶meter)) ||
1084 !CBBFinishArray(transcript.get(), &transcript_data)) {
1085 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
1086 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
1087 return ssl_hs_error;
1088 }
1089
1090 if (!ssl_public_key_verify(ssl, signature, signature_algorithm,
1091 hs->peer_pubkey.get(), transcript_data)) {
1092 // bad signature
1093 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SIGNATURE);
1094 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
1095 return ssl_hs_error;
1096 }
1097 } else {
1098 // PSK ciphers are the only supported certificate-less ciphers.
1099 assert(alg_a == SSL_aPSK);
1100
1101 if (CBS_len(&server_key_exchange) > 0) {
1102 OPENSSL_PUT_ERROR(SSL, SSL_R_EXTRA_DATA_IN_MESSAGE);
1103 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1104 return ssl_hs_error;
1105 }
1106 }
1107
1108 ssl->method->next_message(ssl);
1109 hs->state = state_read_certificate_request;
1110 return ssl_hs_ok;
1111 }
1112
do_read_certificate_request(SSL_HANDSHAKE * hs)1113 static enum ssl_hs_wait_t do_read_certificate_request(SSL_HANDSHAKE *hs) {
1114 SSL *const ssl = hs->ssl;
1115
1116 if (!ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
1117 hs->state = state_read_server_hello_done;
1118 return ssl_hs_ok;
1119 }
1120
1121 SSLMessage msg;
1122 if (!ssl->method->get_message(ssl, &msg)) {
1123 return ssl_hs_read_message;
1124 }
1125
1126 if (msg.type == SSL3_MT_SERVER_HELLO_DONE) {
1127 // If we get here we don't need the handshake buffer as we won't be doing
1128 // client auth.
1129 hs->transcript.FreeBuffer();
1130 hs->state = state_read_server_hello_done;
1131 return ssl_hs_ok;
1132 }
1133
1134 if (!ssl_check_message_type(ssl, msg, SSL3_MT_CERTIFICATE_REQUEST) ||
1135 !ssl_hash_message(hs, msg)) {
1136 return ssl_hs_error;
1137 }
1138
1139 // Get the certificate types.
1140 CBS body = msg.body, certificate_types;
1141 if (!CBS_get_u8_length_prefixed(&body, &certificate_types)) {
1142 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1143 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1144 return ssl_hs_error;
1145 }
1146
1147 if (!hs->certificate_types.CopyFrom(certificate_types)) {
1148 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
1149 return ssl_hs_error;
1150 }
1151
1152 if (ssl_protocol_version(ssl) >= TLS1_2_VERSION) {
1153 CBS supported_signature_algorithms;
1154 if (!CBS_get_u16_length_prefixed(&body, &supported_signature_algorithms) ||
1155 !tls1_parse_peer_sigalgs(hs, &supported_signature_algorithms)) {
1156 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1157 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1158 return ssl_hs_error;
1159 }
1160 }
1161
1162 uint8_t alert = SSL_AD_DECODE_ERROR;
1163 UniquePtr<STACK_OF(CRYPTO_BUFFER)> ca_names =
1164 ssl_parse_client_CA_list(ssl, &alert, &body);
1165 if (!ca_names) {
1166 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
1167 return ssl_hs_error;
1168 }
1169
1170 if (CBS_len(&body) != 0) {
1171 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1172 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1173 return ssl_hs_error;
1174 }
1175
1176 hs->cert_request = true;
1177 hs->ca_names = std::move(ca_names);
1178 ssl->ctx->x509_method->hs_flush_cached_ca_names(hs);
1179
1180 ssl->method->next_message(ssl);
1181 hs->state = state_read_server_hello_done;
1182 return ssl_hs_ok;
1183 }
1184
do_read_server_hello_done(SSL_HANDSHAKE * hs)1185 static enum ssl_hs_wait_t do_read_server_hello_done(SSL_HANDSHAKE *hs) {
1186 SSL *const ssl = hs->ssl;
1187 SSLMessage msg;
1188 if (!ssl->method->get_message(ssl, &msg)) {
1189 return ssl_hs_read_message;
1190 }
1191
1192 if (!ssl_check_message_type(ssl, msg, SSL3_MT_SERVER_HELLO_DONE) ||
1193 !ssl_hash_message(hs, msg)) {
1194 return ssl_hs_error;
1195 }
1196
1197 // ServerHelloDone is empty.
1198 if (CBS_len(&msg.body) != 0) {
1199 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1200 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1201 return ssl_hs_error;
1202 }
1203
1204 // ServerHelloDone should be the end of the flight.
1205 if (ssl->method->has_unprocessed_handshake_data(ssl)) {
1206 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
1207 OPENSSL_PUT_ERROR(SSL, SSL_R_EXCESS_HANDSHAKE_DATA);
1208 return ssl_hs_error;
1209 }
1210
1211 ssl->method->next_message(ssl);
1212 hs->state = state_send_client_certificate;
1213 return ssl_hs_ok;
1214 }
1215
do_send_client_certificate(SSL_HANDSHAKE * hs)1216 static enum ssl_hs_wait_t do_send_client_certificate(SSL_HANDSHAKE *hs) {
1217 SSL *const ssl = hs->ssl;
1218
1219 // The peer didn't request a certificate.
1220 if (!hs->cert_request) {
1221 hs->state = state_send_client_key_exchange;
1222 return ssl_hs_ok;
1223 }
1224
1225 // Call cert_cb to update the certificate.
1226 if (hs->config->cert->cert_cb != NULL) {
1227 int rv = hs->config->cert->cert_cb(ssl, hs->config->cert->cert_cb_arg);
1228 if (rv == 0) {
1229 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
1230 OPENSSL_PUT_ERROR(SSL, SSL_R_CERT_CB_ERROR);
1231 return ssl_hs_error;
1232 }
1233 if (rv < 0) {
1234 hs->state = state_send_client_certificate;
1235 return ssl_hs_x509_lookup;
1236 }
1237 }
1238
1239 if (!ssl_has_certificate(hs)) {
1240 // Without a client certificate, the handshake buffer may be released.
1241 hs->transcript.FreeBuffer();
1242 }
1243
1244 if (!ssl_on_certificate_selected(hs) ||
1245 !ssl_output_cert_chain(hs)) {
1246 return ssl_hs_error;
1247 }
1248
1249
1250 hs->state = state_send_client_key_exchange;
1251 return ssl_hs_ok;
1252 }
1253
1254 static_assert(sizeof(size_t) >= sizeof(unsigned),
1255 "size_t is smaller than unsigned");
1256
do_send_client_key_exchange(SSL_HANDSHAKE * hs)1257 static enum ssl_hs_wait_t do_send_client_key_exchange(SSL_HANDSHAKE *hs) {
1258 SSL *const ssl = hs->ssl;
1259 ScopedCBB cbb;
1260 CBB body;
1261 if (!ssl->method->init_message(ssl, cbb.get(), &body,
1262 SSL3_MT_CLIENT_KEY_EXCHANGE)) {
1263 return ssl_hs_error;
1264 }
1265
1266 Array<uint8_t> pms;
1267 uint32_t alg_k = hs->new_cipher->algorithm_mkey;
1268 uint32_t alg_a = hs->new_cipher->algorithm_auth;
1269 if (ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
1270 const CRYPTO_BUFFER *leaf =
1271 sk_CRYPTO_BUFFER_value(hs->new_session->certs.get(), 0);
1272 CBS leaf_cbs;
1273 CRYPTO_BUFFER_init_CBS(leaf, &leaf_cbs);
1274
1275 // Check the key usage matches the cipher suite. We do this unconditionally
1276 // for non-RSA certificates. In particular, it's needed to distinguish ECDH
1277 // certificates, which we do not support, from ECDSA certificates.
1278 // Historically, we have not checked RSA key usages, so it is controlled by
1279 // a flag for now. See https://crbug.com/795089.
1280 ssl_key_usage_t intended_use = (alg_k & SSL_kRSA)
1281 ? key_usage_encipherment
1282 : key_usage_digital_signature;
1283 if (hs->config->enforce_rsa_key_usage ||
1284 EVP_PKEY_id(hs->peer_pubkey.get()) != EVP_PKEY_RSA) {
1285 if (!ssl_cert_check_key_usage(&leaf_cbs, intended_use)) {
1286 return ssl_hs_error;
1287 }
1288 }
1289 }
1290
1291 // If using a PSK key exchange, prepare the pre-shared key.
1292 unsigned psk_len = 0;
1293 uint8_t psk[PSK_MAX_PSK_LEN];
1294 if (alg_a & SSL_aPSK) {
1295 if (hs->config->psk_client_callback == NULL) {
1296 OPENSSL_PUT_ERROR(SSL, SSL_R_PSK_NO_CLIENT_CB);
1297 return ssl_hs_error;
1298 }
1299
1300 char identity[PSK_MAX_IDENTITY_LEN + 1];
1301 OPENSSL_memset(identity, 0, sizeof(identity));
1302 psk_len = hs->config->psk_client_callback(
1303 ssl, hs->peer_psk_identity_hint.get(), identity, sizeof(identity), psk,
1304 sizeof(psk));
1305 if (psk_len == 0) {
1306 OPENSSL_PUT_ERROR(SSL, SSL_R_PSK_IDENTITY_NOT_FOUND);
1307 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
1308 return ssl_hs_error;
1309 }
1310 assert(psk_len <= PSK_MAX_PSK_LEN);
1311
1312 hs->new_session->psk_identity.reset(OPENSSL_strdup(identity));
1313 if (hs->new_session->psk_identity == nullptr) {
1314 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
1315 return ssl_hs_error;
1316 }
1317
1318 // Write out psk_identity.
1319 CBB child;
1320 if (!CBB_add_u16_length_prefixed(&body, &child) ||
1321 !CBB_add_bytes(&child, (const uint8_t *)identity,
1322 OPENSSL_strnlen(identity, sizeof(identity))) ||
1323 !CBB_flush(&body)) {
1324 return ssl_hs_error;
1325 }
1326 }
1327
1328 // Depending on the key exchange method, compute |pms|.
1329 if (alg_k & SSL_kRSA) {
1330 if (!pms.Init(SSL_MAX_MASTER_KEY_LENGTH)) {
1331 return ssl_hs_error;
1332 }
1333
1334 RSA *rsa = EVP_PKEY_get0_RSA(hs->peer_pubkey.get());
1335 if (rsa == NULL) {
1336 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
1337 return ssl_hs_error;
1338 }
1339
1340 pms[0] = hs->client_version >> 8;
1341 pms[1] = hs->client_version & 0xff;
1342 if (!RAND_bytes(&pms[2], SSL_MAX_MASTER_KEY_LENGTH - 2)) {
1343 return ssl_hs_error;
1344 }
1345
1346 CBB enc_pms;
1347 uint8_t *ptr;
1348 size_t enc_pms_len;
1349 if (!CBB_add_u16_length_prefixed(&body, &enc_pms) ||
1350 !CBB_reserve(&enc_pms, &ptr, RSA_size(rsa)) ||
1351 !RSA_encrypt(rsa, &enc_pms_len, ptr, RSA_size(rsa), pms.data(),
1352 pms.size(), RSA_PKCS1_PADDING) ||
1353 !CBB_did_write(&enc_pms, enc_pms_len) ||
1354 !CBB_flush(&body)) {
1355 return ssl_hs_error;
1356 }
1357 } else if (alg_k & SSL_kECDHE) {
1358 // Generate a keypair and serialize the public half.
1359 CBB child;
1360 if (!CBB_add_u8_length_prefixed(&body, &child)) {
1361 return ssl_hs_error;
1362 }
1363
1364 // Compute the premaster.
1365 uint8_t alert = SSL_AD_DECODE_ERROR;
1366 if (!hs->key_shares[0]->Accept(&child, &pms, &alert, hs->peer_key)) {
1367 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
1368 return ssl_hs_error;
1369 }
1370 if (!CBB_flush(&body)) {
1371 return ssl_hs_error;
1372 }
1373
1374 // The key exchange state may now be discarded.
1375 hs->key_shares[0].reset();
1376 hs->key_shares[1].reset();
1377 hs->peer_key.Reset();
1378 } else if (alg_k & SSL_kPSK) {
1379 // For plain PSK, other_secret is a block of 0s with the same length as
1380 // the pre-shared key.
1381 if (!pms.Init(psk_len)) {
1382 return ssl_hs_error;
1383 }
1384 OPENSSL_memset(pms.data(), 0, pms.size());
1385 } else {
1386 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
1387 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
1388 return ssl_hs_error;
1389 }
1390
1391 // For a PSK cipher suite, other_secret is combined with the pre-shared
1392 // key.
1393 if (alg_a & SSL_aPSK) {
1394 ScopedCBB pms_cbb;
1395 CBB child;
1396 if (!CBB_init(pms_cbb.get(), 2 + psk_len + 2 + pms.size()) ||
1397 !CBB_add_u16_length_prefixed(pms_cbb.get(), &child) ||
1398 !CBB_add_bytes(&child, pms.data(), pms.size()) ||
1399 !CBB_add_u16_length_prefixed(pms_cbb.get(), &child) ||
1400 !CBB_add_bytes(&child, psk, psk_len) ||
1401 !CBBFinishArray(pms_cbb.get(), &pms)) {
1402 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
1403 return ssl_hs_error;
1404 }
1405 }
1406
1407 // The message must be added to the finished hash before calculating the
1408 // master secret.
1409 if (!ssl_add_message_cbb(ssl, cbb.get())) {
1410 return ssl_hs_error;
1411 }
1412
1413 hs->new_session->master_key_length =
1414 tls1_generate_master_secret(hs, hs->new_session->master_key, pms);
1415 if (hs->new_session->master_key_length == 0) {
1416 return ssl_hs_error;
1417 }
1418 hs->new_session->extended_master_secret = hs->extended_master_secret;
1419
1420 hs->state = state_send_client_certificate_verify;
1421 return ssl_hs_ok;
1422 }
1423
do_send_client_certificate_verify(SSL_HANDSHAKE * hs)1424 static enum ssl_hs_wait_t do_send_client_certificate_verify(SSL_HANDSHAKE *hs) {
1425 SSL *const ssl = hs->ssl;
1426
1427 if (!hs->cert_request || !ssl_has_certificate(hs)) {
1428 hs->state = state_send_client_finished;
1429 return ssl_hs_ok;
1430 }
1431
1432 assert(ssl_has_private_key(hs));
1433 ScopedCBB cbb;
1434 CBB body, child;
1435 if (!ssl->method->init_message(ssl, cbb.get(), &body,
1436 SSL3_MT_CERTIFICATE_VERIFY)) {
1437 return ssl_hs_error;
1438 }
1439
1440 uint16_t signature_algorithm;
1441 if (!tls1_choose_signature_algorithm(hs, &signature_algorithm)) {
1442 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
1443 return ssl_hs_error;
1444 }
1445 if (ssl_protocol_version(ssl) >= TLS1_2_VERSION) {
1446 // Write out the digest type in TLS 1.2.
1447 if (!CBB_add_u16(&body, signature_algorithm)) {
1448 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
1449 return ssl_hs_error;
1450 }
1451 }
1452
1453 // Set aside space for the signature.
1454 const size_t max_sig_len = EVP_PKEY_size(hs->local_pubkey.get());
1455 uint8_t *ptr;
1456 if (!CBB_add_u16_length_prefixed(&body, &child) ||
1457 !CBB_reserve(&child, &ptr, max_sig_len)) {
1458 return ssl_hs_error;
1459 }
1460
1461 size_t sig_len = max_sig_len;
1462 switch (ssl_private_key_sign(hs, ptr, &sig_len, max_sig_len,
1463 signature_algorithm,
1464 hs->transcript.buffer())) {
1465 case ssl_private_key_success:
1466 break;
1467 case ssl_private_key_failure:
1468 return ssl_hs_error;
1469 case ssl_private_key_retry:
1470 hs->state = state_send_client_certificate_verify;
1471 return ssl_hs_private_key_operation;
1472 }
1473
1474 if (!CBB_did_write(&child, sig_len) ||
1475 !ssl_add_message_cbb(ssl, cbb.get())) {
1476 return ssl_hs_error;
1477 }
1478
1479 // The handshake buffer is no longer necessary.
1480 hs->transcript.FreeBuffer();
1481
1482 hs->state = state_send_client_finished;
1483 return ssl_hs_ok;
1484 }
1485
do_send_client_finished(SSL_HANDSHAKE * hs)1486 static enum ssl_hs_wait_t do_send_client_finished(SSL_HANDSHAKE *hs) {
1487 SSL *const ssl = hs->ssl;
1488 // Resolve Channel ID first, before any non-idempotent operations.
1489 if (ssl->s3->channel_id_valid) {
1490 if (!ssl_do_channel_id_callback(hs)) {
1491 return ssl_hs_error;
1492 }
1493
1494 if (hs->config->channel_id_private == NULL) {
1495 hs->state = state_send_client_finished;
1496 return ssl_hs_channel_id_lookup;
1497 }
1498 }
1499
1500 if (!ssl->method->add_change_cipher_spec(ssl) ||
1501 !tls1_change_cipher_state(hs, evp_aead_seal)) {
1502 return ssl_hs_error;
1503 }
1504
1505 if (hs->next_proto_neg_seen) {
1506 static const uint8_t kZero[32] = {0};
1507 size_t padding_len =
1508 32 - ((ssl->s3->next_proto_negotiated.size() + 2) % 32);
1509
1510 ScopedCBB cbb;
1511 CBB body, child;
1512 if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_NEXT_PROTO) ||
1513 !CBB_add_u8_length_prefixed(&body, &child) ||
1514 !CBB_add_bytes(&child, ssl->s3->next_proto_negotiated.data(),
1515 ssl->s3->next_proto_negotiated.size()) ||
1516 !CBB_add_u8_length_prefixed(&body, &child) ||
1517 !CBB_add_bytes(&child, kZero, padding_len) ||
1518 !ssl_add_message_cbb(ssl, cbb.get())) {
1519 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
1520 return ssl_hs_error;
1521 }
1522 }
1523
1524 if (ssl->s3->channel_id_valid) {
1525 ScopedCBB cbb;
1526 CBB body;
1527 if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_CHANNEL_ID) ||
1528 !tls1_write_channel_id(hs, &body) ||
1529 !ssl_add_message_cbb(ssl, cbb.get())) {
1530 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
1531 return ssl_hs_error;
1532 }
1533 }
1534
1535 if (!ssl_send_finished(hs)) {
1536 return ssl_hs_error;
1537 }
1538
1539 hs->state = state_finish_flight;
1540 return ssl_hs_flush;
1541 }
1542
can_false_start(const SSL_HANDSHAKE * hs)1543 static bool can_false_start(const SSL_HANDSHAKE *hs) {
1544 SSL *const ssl = hs->ssl;
1545
1546 // False Start bypasses the Finished check's downgrade protection. This can
1547 // enable attacks where we send data under weaker settings than supported
1548 // (e.g. the Logjam attack). Thus we require TLS 1.2 with an ECDHE+AEAD
1549 // cipher, our strongest settings before TLS 1.3.
1550 //
1551 // Now that TLS 1.3 exists, we would like to avoid similar attacks between
1552 // TLS 1.2 and TLS 1.3, but there are too many TLS 1.2 deployments to
1553 // sacrifice False Start on them. TLS 1.3's downgrade signal fixes this, but
1554 // |SSL_CTX_set_ignore_tls13_downgrade| can disable it due to compatibility
1555 // issues.
1556 //
1557 // |SSL_CTX_set_ignore_tls13_downgrade| normally still retains Finished-based
1558 // downgrade protection, but False Start bypasses that. Thus, we disable False
1559 // Start based on the TLS 1.3 downgrade signal, even if otherwise unenforced.
1560 if (SSL_is_dtls(ssl) ||
1561 SSL_version(ssl) != TLS1_2_VERSION ||
1562 hs->new_cipher->algorithm_mkey != SSL_kECDHE ||
1563 hs->new_cipher->algorithm_mac != SSL_AEAD ||
1564 ssl->s3->tls13_downgrade) {
1565 return false;
1566 }
1567
1568 // Additionally require ALPN or NPN by default.
1569 //
1570 // TODO(davidben): Can this constraint be relaxed globally now that cipher
1571 // suite requirements have been tightened?
1572 if (!ssl->ctx->false_start_allowed_without_alpn &&
1573 ssl->s3->alpn_selected.empty() &&
1574 ssl->s3->next_proto_negotiated.empty()) {
1575 return false;
1576 }
1577
1578 return true;
1579 }
1580
do_finish_flight(SSL_HANDSHAKE * hs)1581 static enum ssl_hs_wait_t do_finish_flight(SSL_HANDSHAKE *hs) {
1582 SSL *const ssl = hs->ssl;
1583 if (ssl->session != NULL) {
1584 hs->state = state_finish_client_handshake;
1585 return ssl_hs_ok;
1586 }
1587
1588 // This is a full handshake. If it involves ChannelID, then record the
1589 // handshake hashes at this point in the session so that any resumption of
1590 // this session with ChannelID can sign those hashes.
1591 if (!tls1_record_handshake_hashes_for_channel_id(hs)) {
1592 return ssl_hs_error;
1593 }
1594
1595 hs->state = state_read_session_ticket;
1596
1597 if ((SSL_get_mode(ssl) & SSL_MODE_ENABLE_FALSE_START) &&
1598 can_false_start(hs) &&
1599 // No False Start on renegotiation (would complicate the state machine).
1600 !ssl->s3->initial_handshake_complete) {
1601 hs->in_false_start = true;
1602 hs->can_early_write = true;
1603 return ssl_hs_early_return;
1604 }
1605
1606 return ssl_hs_ok;
1607 }
1608
do_read_session_ticket(SSL_HANDSHAKE * hs)1609 static enum ssl_hs_wait_t do_read_session_ticket(SSL_HANDSHAKE *hs) {
1610 SSL *const ssl = hs->ssl;
1611
1612 if (!hs->ticket_expected) {
1613 hs->state = state_process_change_cipher_spec;
1614 return ssl_hs_read_change_cipher_spec;
1615 }
1616
1617 SSLMessage msg;
1618 if (!ssl->method->get_message(ssl, &msg)) {
1619 return ssl_hs_read_message;
1620 }
1621
1622 if (!ssl_check_message_type(ssl, msg, SSL3_MT_NEW_SESSION_TICKET) ||
1623 !ssl_hash_message(hs, msg)) {
1624 return ssl_hs_error;
1625 }
1626
1627 CBS new_session_ticket = msg.body, ticket;
1628 uint32_t ticket_lifetime_hint;
1629 if (!CBS_get_u32(&new_session_ticket, &ticket_lifetime_hint) ||
1630 !CBS_get_u16_length_prefixed(&new_session_ticket, &ticket) ||
1631 CBS_len(&new_session_ticket) != 0) {
1632 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1633 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1634 return ssl_hs_error;
1635 }
1636
1637 if (CBS_len(&ticket) == 0) {
1638 // RFC 5077 allows a server to change its mind and send no ticket after
1639 // negotiating the extension. The value of |ticket_expected| is checked in
1640 // |ssl_update_cache| so is cleared here to avoid an unnecessary update.
1641 hs->ticket_expected = false;
1642 ssl->method->next_message(ssl);
1643 hs->state = state_process_change_cipher_spec;
1644 return ssl_hs_read_change_cipher_spec;
1645 }
1646
1647 SSL_SESSION *session = hs->new_session.get();
1648 UniquePtr<SSL_SESSION> renewed_session;
1649 if (ssl->session != NULL) {
1650 // The server is sending a new ticket for an existing session. Sessions are
1651 // immutable once established, so duplicate all but the ticket of the
1652 // existing session.
1653 renewed_session =
1654 SSL_SESSION_dup(ssl->session.get(), SSL_SESSION_INCLUDE_NONAUTH);
1655 if (!renewed_session) {
1656 // This should never happen.
1657 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
1658 return ssl_hs_error;
1659 }
1660 session = renewed_session.get();
1661 }
1662
1663 // |ticket_lifetime_hint| is measured from when the ticket was issued.
1664 ssl_session_rebase_time(ssl, session);
1665
1666 if (!session->ticket.CopyFrom(ticket)) {
1667 return ssl_hs_error;
1668 }
1669 session->ticket_lifetime_hint = ticket_lifetime_hint;
1670
1671 // Generate a session ID for this session. Some callers expect all sessions to
1672 // have a session ID. Additionally, it acts as the session ID to signal
1673 // resumption.
1674 SHA256(CBS_data(&ticket), CBS_len(&ticket), session->session_id);
1675 session->session_id_length = SHA256_DIGEST_LENGTH;
1676
1677 if (renewed_session) {
1678 session->not_resumable = false;
1679 ssl->session = std::move(renewed_session);
1680 }
1681
1682 ssl->method->next_message(ssl);
1683 hs->state = state_process_change_cipher_spec;
1684 return ssl_hs_read_change_cipher_spec;
1685 }
1686
do_process_change_cipher_spec(SSL_HANDSHAKE * hs)1687 static enum ssl_hs_wait_t do_process_change_cipher_spec(SSL_HANDSHAKE *hs) {
1688 if (!tls1_change_cipher_state(hs, evp_aead_open)) {
1689 return ssl_hs_error;
1690 }
1691
1692 hs->state = state_read_server_finished;
1693 return ssl_hs_ok;
1694 }
1695
do_read_server_finished(SSL_HANDSHAKE * hs)1696 static enum ssl_hs_wait_t do_read_server_finished(SSL_HANDSHAKE *hs) {
1697 SSL *const ssl = hs->ssl;
1698 enum ssl_hs_wait_t wait = ssl_get_finished(hs);
1699 if (wait != ssl_hs_ok) {
1700 return wait;
1701 }
1702
1703 if (ssl->session != NULL) {
1704 hs->state = state_send_client_finished;
1705 return ssl_hs_ok;
1706 }
1707
1708 hs->state = state_finish_client_handshake;
1709 return ssl_hs_ok;
1710 }
1711
do_finish_client_handshake(SSL_HANDSHAKE * hs)1712 static enum ssl_hs_wait_t do_finish_client_handshake(SSL_HANDSHAKE *hs) {
1713 SSL *const ssl = hs->ssl;
1714
1715 ssl->method->on_handshake_complete(ssl);
1716
1717 if (ssl->session != NULL) {
1718 ssl->s3->established_session = UpRef(ssl->session);
1719 } else {
1720 // We make a copy of the session in order to maintain the immutability
1721 // of the new established_session due to False Start. The caller may
1722 // have taken a reference to the temporary session.
1723 ssl->s3->established_session =
1724 SSL_SESSION_dup(hs->new_session.get(), SSL_SESSION_DUP_ALL);
1725 if (!ssl->s3->established_session) {
1726 return ssl_hs_error;
1727 }
1728 // Renegotiations do not participate in session resumption.
1729 if (!ssl->s3->initial_handshake_complete) {
1730 ssl->s3->established_session->not_resumable = false;
1731 }
1732
1733 hs->new_session.reset();
1734 }
1735
1736 hs->handshake_finalized = true;
1737 ssl->s3->initial_handshake_complete = true;
1738 ssl_update_cache(hs, SSL_SESS_CACHE_CLIENT);
1739
1740 hs->state = state_done;
1741 return ssl_hs_ok;
1742 }
1743
ssl_client_handshake(SSL_HANDSHAKE * hs)1744 enum ssl_hs_wait_t ssl_client_handshake(SSL_HANDSHAKE *hs) {
1745 while (hs->state != state_done) {
1746 enum ssl_hs_wait_t ret = ssl_hs_error;
1747 enum ssl_client_hs_state_t state =
1748 static_cast<enum ssl_client_hs_state_t>(hs->state);
1749 switch (state) {
1750 case state_start_connect:
1751 ret = do_start_connect(hs);
1752 break;
1753 case state_enter_early_data:
1754 ret = do_enter_early_data(hs);
1755 break;
1756 case state_early_reverify_server_certificate:
1757 ret = do_early_reverify_server_certificate(hs);
1758 break;
1759 case state_read_hello_verify_request:
1760 ret = do_read_hello_verify_request(hs);
1761 break;
1762 case state_read_server_hello:
1763 ret = do_read_server_hello(hs);
1764 break;
1765 case state_tls13:
1766 ret = do_tls13(hs);
1767 break;
1768 case state_read_server_certificate:
1769 ret = do_read_server_certificate(hs);
1770 break;
1771 case state_read_certificate_status:
1772 ret = do_read_certificate_status(hs);
1773 break;
1774 case state_verify_server_certificate:
1775 ret = do_verify_server_certificate(hs);
1776 break;
1777 case state_reverify_server_certificate:
1778 ret = do_reverify_server_certificate(hs);
1779 break;
1780 case state_read_server_key_exchange:
1781 ret = do_read_server_key_exchange(hs);
1782 break;
1783 case state_read_certificate_request:
1784 ret = do_read_certificate_request(hs);
1785 break;
1786 case state_read_server_hello_done:
1787 ret = do_read_server_hello_done(hs);
1788 break;
1789 case state_send_client_certificate:
1790 ret = do_send_client_certificate(hs);
1791 break;
1792 case state_send_client_key_exchange:
1793 ret = do_send_client_key_exchange(hs);
1794 break;
1795 case state_send_client_certificate_verify:
1796 ret = do_send_client_certificate_verify(hs);
1797 break;
1798 case state_send_client_finished:
1799 ret = do_send_client_finished(hs);
1800 break;
1801 case state_finish_flight:
1802 ret = do_finish_flight(hs);
1803 break;
1804 case state_read_session_ticket:
1805 ret = do_read_session_ticket(hs);
1806 break;
1807 case state_process_change_cipher_spec:
1808 ret = do_process_change_cipher_spec(hs);
1809 break;
1810 case state_read_server_finished:
1811 ret = do_read_server_finished(hs);
1812 break;
1813 case state_finish_client_handshake:
1814 ret = do_finish_client_handshake(hs);
1815 break;
1816 case state_done:
1817 ret = ssl_hs_ok;
1818 break;
1819 }
1820
1821 if (hs->state != state) {
1822 ssl_do_info_callback(hs->ssl, SSL_CB_CONNECT_LOOP, 1);
1823 }
1824
1825 if (ret != ssl_hs_ok) {
1826 return ret;
1827 }
1828 }
1829
1830 ssl_do_info_callback(hs->ssl, SSL_CB_HANDSHAKE_DONE, 1);
1831 return ssl_hs_ok;
1832 }
1833
ssl_client_handshake_state(SSL_HANDSHAKE * hs)1834 const char *ssl_client_handshake_state(SSL_HANDSHAKE *hs) {
1835 enum ssl_client_hs_state_t state =
1836 static_cast<enum ssl_client_hs_state_t>(hs->state);
1837 switch (state) {
1838 case state_start_connect:
1839 return "TLS client start_connect";
1840 case state_enter_early_data:
1841 return "TLS client enter_early_data";
1842 case state_early_reverify_server_certificate:
1843 return "TLS client early_reverify_server_certificate";
1844 case state_read_hello_verify_request:
1845 return "TLS client read_hello_verify_request";
1846 case state_read_server_hello:
1847 return "TLS client read_server_hello";
1848 case state_tls13:
1849 return tls13_client_handshake_state(hs);
1850 case state_read_server_certificate:
1851 return "TLS client read_server_certificate";
1852 case state_read_certificate_status:
1853 return "TLS client read_certificate_status";
1854 case state_verify_server_certificate:
1855 return "TLS client verify_server_certificate";
1856 case state_reverify_server_certificate:
1857 return "TLS client reverify_server_certificate";
1858 case state_read_server_key_exchange:
1859 return "TLS client read_server_key_exchange";
1860 case state_read_certificate_request:
1861 return "TLS client read_certificate_request";
1862 case state_read_server_hello_done:
1863 return "TLS client read_server_hello_done";
1864 case state_send_client_certificate:
1865 return "TLS client send_client_certificate";
1866 case state_send_client_key_exchange:
1867 return "TLS client send_client_key_exchange";
1868 case state_send_client_certificate_verify:
1869 return "TLS client send_client_certificate_verify";
1870 case state_send_client_finished:
1871 return "TLS client send_client_finished";
1872 case state_finish_flight:
1873 return "TLS client finish_flight";
1874 case state_read_session_ticket:
1875 return "TLS client read_session_ticket";
1876 case state_process_change_cipher_spec:
1877 return "TLS client process_change_cipher_spec";
1878 case state_read_server_finished:
1879 return "TLS client read_server_finished";
1880 case state_finish_client_handshake:
1881 return "TLS client finish_client_handshake";
1882 case state_done:
1883 return "TLS client done";
1884 }
1885
1886 return "TLS client unknown";
1887 }
1888
1889 BSSL_NAMESPACE_END
1890