1 /* Copyright (c) 2016, Google Inc.
2 *
3 * Permission to use, copy, modify, and/or distribute this software for any
4 * purpose with or without fee is hereby granted, provided that the above
5 * copyright notice and this permission notice appear in all copies.
6 *
7 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
8 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
10 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
12 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
13 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
14
15 #include <openssl/ssl.h>
16
17 #include <assert.h>
18 #include <limits.h>
19 #include <string.h>
20
21 #include <utility>
22
23 #include <openssl/bytestring.h>
24 #include <openssl/digest.h>
25 #include <openssl/err.h>
26 #include <openssl/mem.h>
27 #include <openssl/sha.h>
28 #include <openssl/stack.h>
29
30 #include "../crypto/internal.h"
31 #include "internal.h"
32
33
34 BSSL_NAMESPACE_BEGIN
35
36 enum client_hs_state_t {
37 state_read_hello_retry_request = 0,
38 state_send_second_client_hello,
39 state_read_server_hello,
40 state_read_encrypted_extensions,
41 state_read_certificate_request,
42 state_read_server_certificate,
43 state_read_server_certificate_verify,
44 state_server_certificate_reverify,
45 state_read_server_finished,
46 state_send_end_of_early_data,
47 state_send_client_encrypted_extensions,
48 state_send_client_certificate,
49 state_send_client_certificate_verify,
50 state_complete_second_flight,
51 state_done,
52 };
53
54 static const uint8_t kZeroes[EVP_MAX_MD_SIZE] = {0};
55
56 // end_of_early_data closes the early data stream for |hs| and switches the
57 // encryption level to |level|. It returns true on success and false on error.
close_early_data(SSL_HANDSHAKE * hs,ssl_encryption_level_t level)58 static bool close_early_data(SSL_HANDSHAKE *hs, ssl_encryption_level_t level) {
59 SSL *const ssl = hs->ssl;
60 assert(hs->in_early_data);
61
62 // Note |can_early_write| may already be false if |SSL_write| exceeded the
63 // early data write limit.
64 hs->can_early_write = false;
65
66 // 0-RTT write states on the client differ between TLS 1.3, DTLS 1.3, and
67 // QUIC. TLS 1.3 has one write encryption level at a time. 0-RTT write keys
68 // overwrite the null cipher and defer handshake write keys. While a
69 // HelloRetryRequest can cause us to rewind back to the null cipher, sequence
70 // numbers have no effect, so we can install a "new" null cipher.
71 //
72 // In QUIC and DTLS 1.3, 0-RTT write state cannot override or defer the normal
73 // write state. The two ClientHello sequence numbers must align, and handshake
74 // write keys must be installed early to ACK the EncryptedExtensions.
75 //
76 // We do not currently implement DTLS 1.3 and, in QUIC, the caller handles
77 // 0-RTT data, so we can skip installing 0-RTT keys and act as if there is one
78 // write level. If we implement DTLS 1.3, we'll need to model this better.
79 if (ssl->quic_method == nullptr) {
80 if (level == ssl_encryption_initial) {
81 bssl::UniquePtr<SSLAEADContext> null_ctx =
82 SSLAEADContext::CreateNullCipher(SSL_is_dtls(ssl));
83 if (!null_ctx ||
84 !ssl->method->set_write_state(ssl, ssl_encryption_initial,
85 std::move(null_ctx),
86 /*secret_for_quic=*/{})) {
87 return false;
88 }
89 ssl->s3->aead_write_ctx->SetVersionIfNullCipher(ssl->version);
90 } else {
91 assert(level == ssl_encryption_handshake);
92 if (!tls13_set_traffic_key(ssl, ssl_encryption_handshake, evp_aead_seal,
93 hs->new_session.get(),
94 hs->client_handshake_secret())) {
95 return false;
96 }
97 }
98 }
99
100 assert(ssl->s3->write_level == level);
101 return true;
102 }
103
do_read_hello_retry_request(SSL_HANDSHAKE * hs)104 static enum ssl_hs_wait_t do_read_hello_retry_request(SSL_HANDSHAKE *hs) {
105 SSL *const ssl = hs->ssl;
106 assert(ssl->s3->have_version);
107 SSLMessage msg;
108 if (!ssl->method->get_message(ssl, &msg)) {
109 return ssl_hs_read_message;
110 }
111
112 // Queue up a ChangeCipherSpec for whenever we next send something. This
113 // will be before the second ClientHello. If we offered early data, this was
114 // already done.
115 if (!hs->early_data_offered &&
116 !ssl->method->add_change_cipher_spec(ssl)) {
117 return ssl_hs_error;
118 }
119
120 if (!ssl_check_message_type(ssl, msg, SSL3_MT_SERVER_HELLO)) {
121 return ssl_hs_error;
122 }
123
124 CBS body = msg.body, extensions, server_random, session_id;
125 uint16_t server_version, cipher_suite;
126 uint8_t compression_method;
127 if (!CBS_get_u16(&body, &server_version) ||
128 !CBS_get_bytes(&body, &server_random, SSL3_RANDOM_SIZE) ||
129 !CBS_get_u8_length_prefixed(&body, &session_id) ||
130 !CBS_mem_equal(&session_id, hs->session_id, hs->session_id_len) ||
131 !CBS_get_u16(&body, &cipher_suite) ||
132 !CBS_get_u8(&body, &compression_method) ||
133 compression_method != 0 ||
134 !CBS_get_u16_length_prefixed(&body, &extensions) ||
135 CBS_len(&extensions) == 0 ||
136 CBS_len(&body) != 0) {
137 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
138 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
139 return ssl_hs_error;
140 }
141
142 if (!CBS_mem_equal(&server_random, kHelloRetryRequest, SSL3_RANDOM_SIZE)) {
143 hs->tls13_state = state_read_server_hello;
144 return ssl_hs_ok;
145 }
146
147 const SSL_CIPHER *cipher = SSL_get_cipher_by_value(cipher_suite);
148 // Check if the cipher is a TLS 1.3 cipher.
149 if (cipher == NULL ||
150 SSL_CIPHER_get_min_version(cipher) > ssl_protocol_version(ssl) ||
151 SSL_CIPHER_get_max_version(cipher) < ssl_protocol_version(ssl)) {
152 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CIPHER_RETURNED);
153 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
154 return ssl_hs_error;
155 }
156
157 hs->new_cipher = cipher;
158
159 if (!hs->transcript.InitHash(ssl_protocol_version(ssl), hs->new_cipher) ||
160 !hs->transcript.UpdateForHelloRetryRequest()) {
161 return ssl_hs_error;
162 }
163
164
165 bool have_cookie, have_key_share, have_supported_versions;
166 CBS cookie, key_share, supported_versions;
167 SSL_EXTENSION_TYPE ext_types[] = {
168 {TLSEXT_TYPE_key_share, &have_key_share, &key_share},
169 {TLSEXT_TYPE_cookie, &have_cookie, &cookie},
170 {TLSEXT_TYPE_supported_versions, &have_supported_versions,
171 &supported_versions},
172 };
173
174 uint8_t alert = SSL_AD_DECODE_ERROR;
175 if (!ssl_parse_extensions(&extensions, &alert, ext_types,
176 /*ignore_unknown=*/false)) {
177 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
178 return ssl_hs_error;
179 }
180
181 if (!have_cookie && !have_key_share) {
182 OPENSSL_PUT_ERROR(SSL, SSL_R_EMPTY_HELLO_RETRY_REQUEST);
183 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
184 return ssl_hs_error;
185 }
186 if (have_cookie) {
187 CBS cookie_value;
188 if (!CBS_get_u16_length_prefixed(&cookie, &cookie_value) ||
189 CBS_len(&cookie_value) == 0 ||
190 CBS_len(&cookie) != 0) {
191 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
192 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
193 return ssl_hs_error;
194 }
195
196 if (!hs->cookie.CopyFrom(cookie_value)) {
197 return ssl_hs_error;
198 }
199 }
200
201 if (have_key_share) {
202 uint16_t group_id;
203 if (!CBS_get_u16(&key_share, &group_id) || CBS_len(&key_share) != 0) {
204 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
205 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
206 return ssl_hs_error;
207 }
208
209 // The group must be supported.
210 if (!tls1_check_group_id(hs, group_id)) {
211 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
212 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CURVE);
213 return ssl_hs_error;
214 }
215
216 // Check that the HelloRetryRequest does not request a key share that was
217 // provided in the initial ClientHello.
218 if (hs->key_shares[0]->GroupID() == group_id ||
219 (hs->key_shares[1] && hs->key_shares[1]->GroupID() == group_id)) {
220 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
221 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CURVE);
222 return ssl_hs_error;
223 }
224
225 hs->key_shares[0].reset();
226 hs->key_shares[1].reset();
227 hs->retry_group = group_id;
228 }
229
230 if (!ssl_hash_message(hs, msg)) {
231 return ssl_hs_error;
232 }
233
234 // HelloRetryRequest should be the end of the flight.
235 if (ssl->method->has_unprocessed_handshake_data(ssl)) {
236 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
237 OPENSSL_PUT_ERROR(SSL, SSL_R_EXCESS_HANDSHAKE_DATA);
238 return ssl_hs_error;
239 }
240
241 ssl->method->next_message(ssl);
242 ssl->s3->used_hello_retry_request = true;
243 hs->tls13_state = state_send_second_client_hello;
244 // 0-RTT is rejected if we receive a HelloRetryRequest.
245 if (hs->in_early_data) {
246 ssl->s3->early_data_reason = ssl_early_data_hello_retry_request;
247 if (!close_early_data(hs, ssl_encryption_initial)) {
248 return ssl_hs_error;
249 }
250 return ssl_hs_early_data_rejected;
251 }
252 return ssl_hs_ok;
253 }
254
do_send_second_client_hello(SSL_HANDSHAKE * hs)255 static enum ssl_hs_wait_t do_send_second_client_hello(SSL_HANDSHAKE *hs) {
256 // Any 0-RTT keys must have been discarded.
257 assert(hs->ssl->s3->write_level == ssl_encryption_initial);
258
259 if (!ssl_write_client_hello(hs)) {
260 return ssl_hs_error;
261 }
262
263 hs->tls13_state = state_read_server_hello;
264 return ssl_hs_flush;
265 }
266
do_read_server_hello(SSL_HANDSHAKE * hs)267 static enum ssl_hs_wait_t do_read_server_hello(SSL_HANDSHAKE *hs) {
268 SSL *const ssl = hs->ssl;
269 SSLMessage msg;
270 if (!ssl->method->get_message(ssl, &msg)) {
271 return ssl_hs_read_message;
272 }
273 if (!ssl_check_message_type(ssl, msg, SSL3_MT_SERVER_HELLO)) {
274 return ssl_hs_error;
275 }
276
277 CBS body = msg.body, server_random, session_id, extensions;
278 uint16_t server_version;
279 uint16_t cipher_suite;
280 uint8_t compression_method;
281 if (!CBS_get_u16(&body, &server_version) ||
282 !CBS_get_bytes(&body, &server_random, SSL3_RANDOM_SIZE) ||
283 !CBS_get_u8_length_prefixed(&body, &session_id) ||
284 !CBS_mem_equal(&session_id, hs->session_id, hs->session_id_len) ||
285 !CBS_get_u16(&body, &cipher_suite) ||
286 !CBS_get_u8(&body, &compression_method) ||
287 compression_method != 0 ||
288 !CBS_get_u16_length_prefixed(&body, &extensions) ||
289 CBS_len(&body) != 0) {
290 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
291 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
292 return ssl_hs_error;
293 }
294
295 if (server_version != TLS1_2_VERSION) {
296 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
297 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_VERSION_NUMBER);
298 return ssl_hs_error;
299 }
300
301 // Forbid a second HelloRetryRequest.
302 if (CBS_mem_equal(&server_random, kHelloRetryRequest, SSL3_RANDOM_SIZE)) {
303 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
304 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);
305 return ssl_hs_error;
306 }
307
308 OPENSSL_memcpy(ssl->s3->server_random, CBS_data(&server_random),
309 SSL3_RANDOM_SIZE);
310
311 // Check if the cipher is a TLS 1.3 cipher.
312 const SSL_CIPHER *cipher = SSL_get_cipher_by_value(cipher_suite);
313 if (cipher == nullptr ||
314 SSL_CIPHER_get_min_version(cipher) > ssl_protocol_version(ssl) ||
315 SSL_CIPHER_get_max_version(cipher) < ssl_protocol_version(ssl)) {
316 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CIPHER_RETURNED);
317 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
318 return ssl_hs_error;
319 }
320
321 // Check that the cipher matches the one in the HelloRetryRequest.
322 if (ssl->s3->used_hello_retry_request && hs->new_cipher != cipher) {
323 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CIPHER_RETURNED);
324 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
325 return ssl_hs_error;
326 }
327
328 // Parse out the extensions.
329 bool have_key_share = false, have_pre_shared_key = false,
330 have_supported_versions = false;
331 CBS key_share, pre_shared_key, supported_versions;
332 SSL_EXTENSION_TYPE ext_types[] = {
333 {TLSEXT_TYPE_key_share, &have_key_share, &key_share},
334 {TLSEXT_TYPE_pre_shared_key, &have_pre_shared_key, &pre_shared_key},
335 {TLSEXT_TYPE_supported_versions, &have_supported_versions,
336 &supported_versions},
337 };
338
339 uint8_t alert = SSL_AD_DECODE_ERROR;
340 if (!ssl_parse_extensions(&extensions, &alert, ext_types,
341 /*ignore_unknown=*/false)) {
342 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
343 return ssl_hs_error;
344 }
345
346 // Recheck supported_versions, in case this is the second ServerHello.
347 uint16_t version;
348 if (!have_supported_versions ||
349 !CBS_get_u16(&supported_versions, &version) ||
350 version != ssl->version) {
351 OPENSSL_PUT_ERROR(SSL, SSL_R_SECOND_SERVERHELLO_VERSION_MISMATCH);
352 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
353 return ssl_hs_error;
354 }
355
356 alert = SSL_AD_DECODE_ERROR;
357 if (have_pre_shared_key) {
358 if (ssl->session == NULL) {
359 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION);
360 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNSUPPORTED_EXTENSION);
361 return ssl_hs_error;
362 }
363
364 if (!ssl_ext_pre_shared_key_parse_serverhello(hs, &alert,
365 &pre_shared_key)) {
366 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
367 return ssl_hs_error;
368 }
369
370 if (ssl->session->ssl_version != ssl->version) {
371 OPENSSL_PUT_ERROR(SSL, SSL_R_OLD_SESSION_VERSION_NOT_RETURNED);
372 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
373 return ssl_hs_error;
374 }
375
376 if (ssl->session->cipher->algorithm_prf != cipher->algorithm_prf) {
377 OPENSSL_PUT_ERROR(SSL, SSL_R_OLD_SESSION_PRF_HASH_MISMATCH);
378 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
379 return ssl_hs_error;
380 }
381
382 if (!ssl_session_is_context_valid(hs, ssl->session.get())) {
383 // This is actually a client application bug.
384 OPENSSL_PUT_ERROR(SSL,
385 SSL_R_ATTEMPT_TO_REUSE_SESSION_IN_DIFFERENT_CONTEXT);
386 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
387 return ssl_hs_error;
388 }
389
390 ssl->s3->session_reused = true;
391 // Only authentication information carries over in TLS 1.3.
392 hs->new_session =
393 SSL_SESSION_dup(ssl->session.get(), SSL_SESSION_DUP_AUTH_ONLY);
394 if (!hs->new_session) {
395 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
396 return ssl_hs_error;
397 }
398 ssl_set_session(ssl, NULL);
399
400 // Resumption incorporates fresh key material, so refresh the timeout.
401 ssl_session_renew_timeout(ssl, hs->new_session.get(),
402 ssl->session_ctx->session_psk_dhe_timeout);
403 } else if (!ssl_get_new_session(hs, 0)) {
404 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
405 return ssl_hs_error;
406 }
407
408 hs->new_session->cipher = cipher;
409 hs->new_cipher = cipher;
410
411 size_t hash_len =
412 EVP_MD_size(ssl_get_handshake_digest(ssl_protocol_version(ssl), cipher));
413
414 // Set up the key schedule and incorporate the PSK into the running secret.
415 if (ssl->s3->session_reused) {
416 if (!tls13_init_key_schedule(
417 hs, MakeConstSpan(hs->new_session->secret,
418 hs->new_session->secret_length))) {
419 return ssl_hs_error;
420 }
421 } else if (!tls13_init_key_schedule(hs, MakeConstSpan(kZeroes, hash_len))) {
422 return ssl_hs_error;
423 }
424
425 if (!have_key_share) {
426 // We do not support psk_ke and thus always require a key share.
427 OPENSSL_PUT_ERROR(SSL, SSL_R_MISSING_KEY_SHARE);
428 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_MISSING_EXTENSION);
429 return ssl_hs_error;
430 }
431
432 // Resolve ECDHE and incorporate it into the secret.
433 Array<uint8_t> dhe_secret;
434 alert = SSL_AD_DECODE_ERROR;
435 if (!ssl_ext_key_share_parse_serverhello(hs, &dhe_secret, &alert,
436 &key_share)) {
437 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
438 return ssl_hs_error;
439 }
440
441 if (!tls13_advance_key_schedule(hs, dhe_secret) ||
442 !ssl_hash_message(hs, msg) ||
443 !tls13_derive_handshake_secrets(hs)) {
444 return ssl_hs_error;
445 }
446
447 // If currently sending early data over TCP, we defer installing client
448 // traffic keys to when the early data stream is closed. See
449 // |close_early_data|. Note if the server has already rejected 0-RTT via
450 // HelloRetryRequest, |in_early_data| is already false.
451 if (!hs->in_early_data || ssl->quic_method != nullptr) {
452 if (!tls13_set_traffic_key(ssl, ssl_encryption_handshake, evp_aead_seal,
453 hs->new_session.get(),
454 hs->client_handshake_secret())) {
455 return ssl_hs_error;
456 }
457 }
458
459 if (!tls13_set_traffic_key(ssl, ssl_encryption_handshake, evp_aead_open,
460 hs->new_session.get(),
461 hs->server_handshake_secret())) {
462 return ssl_hs_error;
463 }
464
465 ssl->method->next_message(ssl);
466 hs->tls13_state = state_read_encrypted_extensions;
467 return ssl_hs_ok;
468 }
469
do_read_encrypted_extensions(SSL_HANDSHAKE * hs)470 static enum ssl_hs_wait_t do_read_encrypted_extensions(SSL_HANDSHAKE *hs) {
471 SSL *const ssl = hs->ssl;
472 SSLMessage msg;
473 if (!ssl->method->get_message(ssl, &msg)) {
474 return ssl_hs_read_message;
475 }
476 if (!ssl_check_message_type(ssl, msg, SSL3_MT_ENCRYPTED_EXTENSIONS)) {
477 return ssl_hs_error;
478 }
479
480 CBS body = msg.body;
481 if (!ssl_parse_serverhello_tlsext(hs, &body)) {
482 OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT);
483 return ssl_hs_error;
484 }
485 if (CBS_len(&body) != 0) {
486 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
487 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
488 return ssl_hs_error;
489 }
490
491 if (ssl->s3->early_data_accepted) {
492 if (hs->early_session->cipher != hs->new_session->cipher) {
493 OPENSSL_PUT_ERROR(SSL, SSL_R_CIPHER_MISMATCH_ON_EARLY_DATA);
494 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
495 return ssl_hs_error;
496 }
497 if (MakeConstSpan(hs->early_session->early_alpn) !=
498 ssl->s3->alpn_selected) {
499 OPENSSL_PUT_ERROR(SSL, SSL_R_ALPN_MISMATCH_ON_EARLY_DATA);
500 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
501 return ssl_hs_error;
502 }
503 // Channel ID and Token Binding are incompatible with 0-RTT. The ALPS
504 // extension should be negotiated implicitly.
505 if (ssl->s3->channel_id_valid || ssl->s3->token_binding_negotiated ||
506 hs->new_session->has_application_settings) {
507 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION_ON_EARLY_DATA);
508 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
509 return ssl_hs_error;
510 }
511 hs->new_session->has_application_settings =
512 hs->early_session->has_application_settings;
513 if (!hs->new_session->local_application_settings.CopyFrom(
514 hs->early_session->local_application_settings) ||
515 !hs->new_session->peer_application_settings.CopyFrom(
516 hs->early_session->peer_application_settings)) {
517 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
518 return ssl_hs_error;
519 }
520 }
521
522 // Store the negotiated ALPN in the session.
523 if (!hs->new_session->early_alpn.CopyFrom(ssl->s3->alpn_selected)) {
524 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
525 return ssl_hs_error;
526 }
527
528 if (!ssl_hash_message(hs, msg)) {
529 return ssl_hs_error;
530 }
531
532 ssl->method->next_message(ssl);
533 hs->tls13_state = state_read_certificate_request;
534 if (hs->in_early_data && !ssl->s3->early_data_accepted) {
535 if (!close_early_data(hs, ssl_encryption_handshake)) {
536 return ssl_hs_error;
537 }
538 return ssl_hs_early_data_rejected;
539 }
540 return ssl_hs_ok;
541 }
542
do_read_certificate_request(SSL_HANDSHAKE * hs)543 static enum ssl_hs_wait_t do_read_certificate_request(SSL_HANDSHAKE *hs) {
544 SSL *const ssl = hs->ssl;
545 // CertificateRequest may only be sent in non-resumption handshakes.
546 if (ssl->s3->session_reused) {
547 if (ssl->ctx->reverify_on_resume && !ssl->s3->early_data_accepted) {
548 hs->tls13_state = state_server_certificate_reverify;
549 return ssl_hs_ok;
550 }
551 hs->tls13_state = state_read_server_finished;
552 return ssl_hs_ok;
553 }
554
555 SSLMessage msg;
556 if (!ssl->method->get_message(ssl, &msg)) {
557 return ssl_hs_read_message;
558 }
559
560 // CertificateRequest is optional.
561 if (msg.type != SSL3_MT_CERTIFICATE_REQUEST) {
562 hs->tls13_state = state_read_server_certificate;
563 return ssl_hs_ok;
564 }
565
566
567 bool have_sigalgs = false, have_ca = false;
568 CBS sigalgs, ca;
569 const SSL_EXTENSION_TYPE ext_types[] = {
570 {TLSEXT_TYPE_signature_algorithms, &have_sigalgs, &sigalgs},
571 {TLSEXT_TYPE_certificate_authorities, &have_ca, &ca},
572 };
573
574 CBS body = msg.body, context, extensions, supported_signature_algorithms;
575 uint8_t alert = SSL_AD_DECODE_ERROR;
576 if (!CBS_get_u8_length_prefixed(&body, &context) ||
577 // The request context is always empty during the handshake.
578 CBS_len(&context) != 0 ||
579 !CBS_get_u16_length_prefixed(&body, &extensions) ||
580 CBS_len(&body) != 0 ||
581 !ssl_parse_extensions(&extensions, &alert, ext_types,
582 /*ignore_unknown=*/true) ||
583 (have_ca && CBS_len(&ca) == 0) ||
584 !have_sigalgs ||
585 !CBS_get_u16_length_prefixed(&sigalgs,
586 &supported_signature_algorithms) ||
587 !tls1_parse_peer_sigalgs(hs, &supported_signature_algorithms)) {
588 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
589 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
590 return ssl_hs_error;
591 }
592
593 if (have_ca) {
594 hs->ca_names = ssl_parse_client_CA_list(ssl, &alert, &ca);
595 if (!hs->ca_names) {
596 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
597 return ssl_hs_error;
598 }
599 } else {
600 hs->ca_names.reset(sk_CRYPTO_BUFFER_new_null());
601 if (!hs->ca_names) {
602 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
603 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
604 return ssl_hs_error;
605 }
606 }
607
608 hs->cert_request = true;
609 ssl->ctx->x509_method->hs_flush_cached_ca_names(hs);
610
611 if (!ssl_hash_message(hs, msg)) {
612 return ssl_hs_error;
613 }
614
615 ssl->method->next_message(ssl);
616 hs->tls13_state = state_read_server_certificate;
617 return ssl_hs_ok;
618 }
619
do_read_server_certificate(SSL_HANDSHAKE * hs)620 static enum ssl_hs_wait_t do_read_server_certificate(SSL_HANDSHAKE *hs) {
621 SSL *const ssl = hs->ssl;
622 SSLMessage msg;
623 if (!ssl->method->get_message(ssl, &msg)) {
624 return ssl_hs_read_message;
625 }
626
627 if (msg.type != SSL3_MT_COMPRESSED_CERTIFICATE &&
628 !ssl_check_message_type(ssl, msg, SSL3_MT_CERTIFICATE)) {
629 return ssl_hs_error;
630 }
631
632 if (!tls13_process_certificate(hs, msg, false /* certificate required */) ||
633 !ssl_hash_message(hs, msg)) {
634 return ssl_hs_error;
635 }
636
637 ssl->method->next_message(ssl);
638 hs->tls13_state = state_read_server_certificate_verify;
639 return ssl_hs_ok;
640 }
641
do_read_server_certificate_verify(SSL_HANDSHAKE * hs)642 static enum ssl_hs_wait_t do_read_server_certificate_verify(SSL_HANDSHAKE *hs) {
643 SSL *const ssl = hs->ssl;
644 SSLMessage msg;
645 if (!ssl->method->get_message(ssl, &msg)) {
646 return ssl_hs_read_message;
647 }
648 switch (ssl_verify_peer_cert(hs)) {
649 case ssl_verify_ok:
650 break;
651 case ssl_verify_invalid:
652 return ssl_hs_error;
653 case ssl_verify_retry:
654 hs->tls13_state = state_read_server_certificate_verify;
655 return ssl_hs_certificate_verify;
656 }
657
658 if (!ssl_check_message_type(ssl, msg, SSL3_MT_CERTIFICATE_VERIFY) ||
659 !tls13_process_certificate_verify(hs, msg) ||
660 !ssl_hash_message(hs, msg)) {
661 return ssl_hs_error;
662 }
663
664 ssl->method->next_message(ssl);
665 hs->tls13_state = state_read_server_finished;
666 return ssl_hs_ok;
667 }
668
do_server_certificate_reverify(SSL_HANDSHAKE * hs)669 static enum ssl_hs_wait_t do_server_certificate_reverify(SSL_HANDSHAKE *hs) {
670 switch (ssl_reverify_peer_cert(hs, /*send_alert=*/true)) {
671 case ssl_verify_ok:
672 break;
673 case ssl_verify_invalid:
674 return ssl_hs_error;
675 case ssl_verify_retry:
676 hs->tls13_state = state_server_certificate_reverify;
677 return ssl_hs_certificate_verify;
678 }
679 hs->tls13_state = state_read_server_finished;
680 return ssl_hs_ok;
681 }
682
do_read_server_finished(SSL_HANDSHAKE * hs)683 static enum ssl_hs_wait_t do_read_server_finished(SSL_HANDSHAKE *hs) {
684 SSL *const ssl = hs->ssl;
685 SSLMessage msg;
686 if (!ssl->method->get_message(ssl, &msg)) {
687 return ssl_hs_read_message;
688 }
689 if (!ssl_check_message_type(ssl, msg, SSL3_MT_FINISHED) ||
690 !tls13_process_finished(hs, msg, false /* don't use saved value */) ||
691 !ssl_hash_message(hs, msg) ||
692 // Update the secret to the master secret and derive traffic keys.
693 !tls13_advance_key_schedule(
694 hs, MakeConstSpan(kZeroes, hs->transcript.DigestLen())) ||
695 !tls13_derive_application_secrets(hs)) {
696 return ssl_hs_error;
697 }
698
699 // Finished should be the end of the flight.
700 if (ssl->method->has_unprocessed_handshake_data(ssl)) {
701 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
702 OPENSSL_PUT_ERROR(SSL, SSL_R_EXCESS_HANDSHAKE_DATA);
703 return ssl_hs_error;
704 }
705
706 ssl->method->next_message(ssl);
707 hs->tls13_state = state_send_end_of_early_data;
708 return ssl_hs_ok;
709 }
710
do_send_end_of_early_data(SSL_HANDSHAKE * hs)711 static enum ssl_hs_wait_t do_send_end_of_early_data(SSL_HANDSHAKE *hs) {
712 SSL *const ssl = hs->ssl;
713
714 if (ssl->s3->early_data_accepted) {
715 // QUIC omits the EndOfEarlyData message. See draft-ietf-quic-tls-22,
716 // section 8.3.
717 if (ssl->quic_method == nullptr) {
718 ScopedCBB cbb;
719 CBB body;
720 if (!ssl->method->init_message(ssl, cbb.get(), &body,
721 SSL3_MT_END_OF_EARLY_DATA) ||
722 !ssl_add_message_cbb(ssl, cbb.get())) {
723 return ssl_hs_error;
724 }
725 }
726
727 if (!close_early_data(hs, ssl_encryption_handshake)) {
728 return ssl_hs_error;
729 }
730 }
731
732 hs->tls13_state = state_send_client_encrypted_extensions;
733 return ssl_hs_ok;
734 }
735
do_send_client_encrypted_extensions(SSL_HANDSHAKE * hs)736 static enum ssl_hs_wait_t do_send_client_encrypted_extensions(
737 SSL_HANDSHAKE *hs) {
738 SSL *const ssl = hs->ssl;
739 // For now, only one extension uses client EncryptedExtensions. This function
740 // may be generalized if others use it in the future.
741 if (hs->new_session->has_application_settings &&
742 !ssl->s3->early_data_accepted) {
743 ScopedCBB cbb;
744 CBB body, extensions, extension;
745 if (!ssl->method->init_message(ssl, cbb.get(), &body,
746 SSL3_MT_ENCRYPTED_EXTENSIONS) ||
747 !CBB_add_u16_length_prefixed(&body, &extensions) ||
748 !CBB_add_u16(&extensions, TLSEXT_TYPE_application_settings) ||
749 !CBB_add_u16_length_prefixed(&extensions, &extension) ||
750 !CBB_add_bytes(&extension,
751 hs->new_session->local_application_settings.data(),
752 hs->new_session->local_application_settings.size()) ||
753 !ssl_add_message_cbb(ssl, cbb.get())) {
754 return ssl_hs_error;
755 }
756 }
757
758 hs->tls13_state = state_send_client_certificate;
759 return ssl_hs_ok;
760 }
761
do_send_client_certificate(SSL_HANDSHAKE * hs)762 static enum ssl_hs_wait_t do_send_client_certificate(SSL_HANDSHAKE *hs) {
763 SSL *const ssl = hs->ssl;
764
765 // The peer didn't request a certificate.
766 if (!hs->cert_request) {
767 hs->tls13_state = state_complete_second_flight;
768 return ssl_hs_ok;
769 }
770
771 // Call cert_cb to update the certificate.
772 if (hs->config->cert->cert_cb != NULL) {
773 int rv = hs->config->cert->cert_cb(ssl, hs->config->cert->cert_cb_arg);
774 if (rv == 0) {
775 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
776 OPENSSL_PUT_ERROR(SSL, SSL_R_CERT_CB_ERROR);
777 return ssl_hs_error;
778 }
779 if (rv < 0) {
780 hs->tls13_state = state_send_client_certificate;
781 return ssl_hs_x509_lookup;
782 }
783 }
784
785 if (!ssl_on_certificate_selected(hs) ||
786 !tls13_add_certificate(hs)) {
787 return ssl_hs_error;
788 }
789
790 hs->tls13_state = state_send_client_certificate_verify;
791 return ssl_hs_ok;
792 }
793
do_send_client_certificate_verify(SSL_HANDSHAKE * hs)794 static enum ssl_hs_wait_t do_send_client_certificate_verify(SSL_HANDSHAKE *hs) {
795 // Don't send CertificateVerify if there is no certificate.
796 if (!ssl_has_certificate(hs)) {
797 hs->tls13_state = state_complete_second_flight;
798 return ssl_hs_ok;
799 }
800
801 switch (tls13_add_certificate_verify(hs)) {
802 case ssl_private_key_success:
803 hs->tls13_state = state_complete_second_flight;
804 return ssl_hs_ok;
805
806 case ssl_private_key_retry:
807 hs->tls13_state = state_send_client_certificate_verify;
808 return ssl_hs_private_key_operation;
809
810 case ssl_private_key_failure:
811 return ssl_hs_error;
812 }
813
814 assert(0);
815 return ssl_hs_error;
816 }
817
do_complete_second_flight(SSL_HANDSHAKE * hs)818 static enum ssl_hs_wait_t do_complete_second_flight(SSL_HANDSHAKE *hs) {
819 SSL *const ssl = hs->ssl;
820
821 // Send a Channel ID assertion if necessary.
822 if (ssl->s3->channel_id_valid) {
823 if (!ssl_do_channel_id_callback(hs)) {
824 hs->tls13_state = state_complete_second_flight;
825 return ssl_hs_error;
826 }
827
828 if (hs->config->channel_id_private == NULL) {
829 return ssl_hs_channel_id_lookup;
830 }
831
832 ScopedCBB cbb;
833 CBB body;
834 if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_CHANNEL_ID) ||
835 !tls1_write_channel_id(hs, &body) ||
836 !ssl_add_message_cbb(ssl, cbb.get())) {
837 return ssl_hs_error;
838 }
839 }
840
841 // Send a Finished message.
842 if (!tls13_add_finished(hs)) {
843 return ssl_hs_error;
844 }
845
846 // Derive the final keys and enable them.
847 if (!tls13_set_traffic_key(ssl, ssl_encryption_application, evp_aead_seal,
848 hs->new_session.get(),
849 hs->client_traffic_secret_0()) ||
850 !tls13_set_traffic_key(ssl, ssl_encryption_application, evp_aead_open,
851 hs->new_session.get(),
852 hs->server_traffic_secret_0()) ||
853 !tls13_derive_resumption_secret(hs)) {
854 return ssl_hs_error;
855 }
856
857 hs->tls13_state = state_done;
858 return ssl_hs_flush;
859 }
860
tls13_client_handshake(SSL_HANDSHAKE * hs)861 enum ssl_hs_wait_t tls13_client_handshake(SSL_HANDSHAKE *hs) {
862 while (hs->tls13_state != state_done) {
863 enum ssl_hs_wait_t ret = ssl_hs_error;
864 enum client_hs_state_t state =
865 static_cast<enum client_hs_state_t>(hs->tls13_state);
866 switch (state) {
867 case state_read_hello_retry_request:
868 ret = do_read_hello_retry_request(hs);
869 break;
870 case state_send_second_client_hello:
871 ret = do_send_second_client_hello(hs);
872 break;
873 case state_read_server_hello:
874 ret = do_read_server_hello(hs);
875 break;
876 case state_read_encrypted_extensions:
877 ret = do_read_encrypted_extensions(hs);
878 break;
879 case state_read_certificate_request:
880 ret = do_read_certificate_request(hs);
881 break;
882 case state_read_server_certificate:
883 ret = do_read_server_certificate(hs);
884 break;
885 case state_read_server_certificate_verify:
886 ret = do_read_server_certificate_verify(hs);
887 break;
888 case state_server_certificate_reverify:
889 ret = do_server_certificate_reverify(hs);
890 break;
891 case state_read_server_finished:
892 ret = do_read_server_finished(hs);
893 break;
894 case state_send_end_of_early_data:
895 ret = do_send_end_of_early_data(hs);
896 break;
897 case state_send_client_certificate:
898 ret = do_send_client_certificate(hs);
899 break;
900 case state_send_client_encrypted_extensions:
901 ret = do_send_client_encrypted_extensions(hs);
902 break;
903 case state_send_client_certificate_verify:
904 ret = do_send_client_certificate_verify(hs);
905 break;
906 case state_complete_second_flight:
907 ret = do_complete_second_flight(hs);
908 break;
909 case state_done:
910 ret = ssl_hs_ok;
911 break;
912 }
913
914 if (hs->tls13_state != state) {
915 ssl_do_info_callback(hs->ssl, SSL_CB_CONNECT_LOOP, 1);
916 }
917
918 if (ret != ssl_hs_ok) {
919 return ret;
920 }
921 }
922
923 return ssl_hs_ok;
924 }
925
tls13_client_handshake_state(SSL_HANDSHAKE * hs)926 const char *tls13_client_handshake_state(SSL_HANDSHAKE *hs) {
927 enum client_hs_state_t state =
928 static_cast<enum client_hs_state_t>(hs->tls13_state);
929 switch (state) {
930 case state_read_hello_retry_request:
931 return "TLS 1.3 client read_hello_retry_request";
932 case state_send_second_client_hello:
933 return "TLS 1.3 client send_second_client_hello";
934 case state_read_server_hello:
935 return "TLS 1.3 client read_server_hello";
936 case state_read_encrypted_extensions:
937 return "TLS 1.3 client read_encrypted_extensions";
938 case state_read_certificate_request:
939 return "TLS 1.3 client read_certificate_request";
940 case state_read_server_certificate:
941 return "TLS 1.3 client read_server_certificate";
942 case state_read_server_certificate_verify:
943 return "TLS 1.3 client read_server_certificate_verify";
944 case state_server_certificate_reverify:
945 return "TLS 1.3 client server_certificate_reverify";
946 case state_read_server_finished:
947 return "TLS 1.3 client read_server_finished";
948 case state_send_end_of_early_data:
949 return "TLS 1.3 client send_end_of_early_data";
950 case state_send_client_encrypted_extensions:
951 return "TLS 1.3 client send_client_encrypted_extensions";
952 case state_send_client_certificate:
953 return "TLS 1.3 client send_client_certificate";
954 case state_send_client_certificate_verify:
955 return "TLS 1.3 client send_client_certificate_verify";
956 case state_complete_second_flight:
957 return "TLS 1.3 client complete_second_flight";
958 case state_done:
959 return "TLS 1.3 client done";
960 }
961
962 return "TLS 1.3 client unknown";
963 }
964
tls13_process_new_session_ticket(SSL * ssl,const SSLMessage & msg)965 bool tls13_process_new_session_ticket(SSL *ssl, const SSLMessage &msg) {
966 if (ssl->s3->write_shutdown != ssl_shutdown_none) {
967 // Ignore tickets on shutdown. Callers tend to indiscriminately call
968 // |SSL_shutdown| before destroying an |SSL|, at which point calling the new
969 // session callback may be confusing.
970 return true;
971 }
972
973 CBS body = msg.body;
974 UniquePtr<SSL_SESSION> session = tls13_create_session_with_ticket(ssl, &body);
975 if (!session) {
976 return false;
977 }
978
979 if ((ssl->session_ctx->session_cache_mode & SSL_SESS_CACHE_CLIENT) &&
980 ssl->session_ctx->new_session_cb != NULL &&
981 ssl->session_ctx->new_session_cb(ssl, session.get())) {
982 // |new_session_cb|'s return value signals that it took ownership.
983 session.release();
984 }
985
986 return true;
987 }
988
tls13_create_session_with_ticket(SSL * ssl,CBS * body)989 UniquePtr<SSL_SESSION> tls13_create_session_with_ticket(SSL *ssl, CBS *body) {
990 UniquePtr<SSL_SESSION> session = SSL_SESSION_dup(
991 ssl->s3->established_session.get(), SSL_SESSION_INCLUDE_NONAUTH);
992 if (!session) {
993 return nullptr;
994 }
995
996 ssl_session_rebase_time(ssl, session.get());
997
998 uint32_t server_timeout;
999 CBS ticket_nonce, ticket, extensions;
1000 if (!CBS_get_u32(body, &server_timeout) ||
1001 !CBS_get_u32(body, &session->ticket_age_add) ||
1002 !CBS_get_u8_length_prefixed(body, &ticket_nonce) ||
1003 !CBS_get_u16_length_prefixed(body, &ticket) ||
1004 !session->ticket.CopyFrom(ticket) ||
1005 !CBS_get_u16_length_prefixed(body, &extensions) ||
1006 CBS_len(body) != 0) {
1007 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1008 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1009 return nullptr;
1010 }
1011
1012 // Cap the renewable lifetime by the server advertised value. This avoids
1013 // wasting bandwidth on 0-RTT when we know the server will reject it.
1014 if (session->timeout > server_timeout) {
1015 session->timeout = server_timeout;
1016 }
1017
1018 if (!tls13_derive_session_psk(session.get(), ticket_nonce)) {
1019 return nullptr;
1020 }
1021
1022 // Parse out the extensions.
1023 bool have_early_data = false;
1024 CBS early_data;
1025 const SSL_EXTENSION_TYPE ext_types[] = {
1026 {TLSEXT_TYPE_early_data, &have_early_data, &early_data},
1027 };
1028
1029 uint8_t alert = SSL_AD_DECODE_ERROR;
1030 if (!ssl_parse_extensions(&extensions, &alert, ext_types,
1031 /*ignore_unknown=*/true)) {
1032 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
1033 return nullptr;
1034 }
1035
1036 if (have_early_data) {
1037 if (!CBS_get_u32(&early_data, &session->ticket_max_early_data) ||
1038 CBS_len(&early_data) != 0) {
1039 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1040 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1041 return nullptr;
1042 }
1043
1044 // QUIC does not use the max_early_data_size parameter and always sets it to
1045 // a fixed value. See draft-ietf-quic-tls-22, section 4.5.
1046 if (ssl->quic_method != nullptr &&
1047 session->ticket_max_early_data != 0xffffffff) {
1048 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
1049 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1050 return nullptr;
1051 }
1052 }
1053
1054 // Generate a session ID for this session. Some callers expect all sessions to
1055 // have a session ID.
1056 SHA256(CBS_data(&ticket), CBS_len(&ticket), session->session_id);
1057 session->session_id_length = SHA256_DIGEST_LENGTH;
1058
1059 session->ticket_age_add_valid = true;
1060 session->not_resumable = false;
1061
1062 return session;
1063 }
1064
1065 BSSL_NAMESPACE_END
1066