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_certificate,
48 state_send_client_certificate_verify,
49 state_complete_second_flight,
50 state_done,
51 };
52
53 static const uint8_t kZeroes[EVP_MAX_MD_SIZE] = {0};
54
55 // end_of_early_data closes the early data stream for |hs| and switches the
56 // encryption level to |level|. It returns true on success and false on error.
close_early_data(SSL_HANDSHAKE * hs,ssl_encryption_level_t level)57 static bool close_early_data(SSL_HANDSHAKE *hs, ssl_encryption_level_t level) {
58 SSL *const ssl = hs->ssl;
59 assert(hs->in_early_data);
60
61 // Note |can_early_write| may already be false if |SSL_write| exceeded the
62 // early data write limit.
63 hs->can_early_write = false;
64
65 // 0-RTT write states on the client differ between TLS 1.3, DTLS 1.3, and
66 // QUIC. TLS 1.3 has one write encryption level at a time. 0-RTT write keys
67 // overwrite the null cipher and defer handshake write keys. While a
68 // HelloRetryRequest can cause us to rewind back to the null cipher, sequence
69 // numbers have no effect, so we can install a "new" null cipher.
70 //
71 // In QUIC and DTLS 1.3, 0-RTT write state cannot override or defer the normal
72 // write state. The two ClientHello sequence numbers must align, and handshake
73 // write keys must be installed early to ACK the EncryptedExtensions.
74 //
75 // We do not currently implement DTLS 1.3 and, in QUIC, the caller handles
76 // 0-RTT data, so we can skip installing 0-RTT keys and act as if there is one
77 // write level. If we implement DTLS 1.3, we'll need to model this better.
78 if (ssl->quic_method == nullptr) {
79 if (level == ssl_encryption_initial) {
80 bssl::UniquePtr<SSLAEADContext> null_ctx =
81 SSLAEADContext::CreateNullCipher(SSL_is_dtls(ssl));
82 if (!null_ctx ||
83 !ssl->method->set_write_state(ssl, ssl_encryption_initial,
84 std::move(null_ctx),
85 /*secret_for_quic=*/{})) {
86 return false;
87 }
88 ssl->s3->aead_write_ctx->SetVersionIfNullCipher(ssl->version);
89 } else {
90 assert(level == ssl_encryption_handshake);
91 if (!tls13_set_traffic_key(ssl, ssl_encryption_handshake, evp_aead_seal,
92 hs->new_session.get(),
93 hs->client_handshake_secret())) {
94 return false;
95 }
96 }
97 }
98
99 assert(ssl->s3->write_level == level);
100 return true;
101 }
102
do_read_hello_retry_request(SSL_HANDSHAKE * hs)103 static enum ssl_hs_wait_t do_read_hello_retry_request(SSL_HANDSHAKE *hs) {
104 SSL *const ssl = hs->ssl;
105 assert(ssl->s3->have_version);
106 SSLMessage msg;
107 if (!ssl->method->get_message(ssl, &msg)) {
108 return ssl_hs_read_message;
109 }
110
111 // Queue up a ChangeCipherSpec for whenever we next send something. This
112 // will be before the second ClientHello. If we offered early data, this was
113 // already done.
114 if (!hs->early_data_offered &&
115 !ssl->method->add_change_cipher_spec(ssl)) {
116 return ssl_hs_error;
117 }
118
119 if (!ssl_check_message_type(ssl, msg, SSL3_MT_SERVER_HELLO)) {
120 return ssl_hs_error;
121 }
122
123 CBS body = msg.body, extensions, server_random, session_id;
124 uint16_t server_version, cipher_suite;
125 uint8_t compression_method;
126 if (!CBS_get_u16(&body, &server_version) ||
127 !CBS_get_bytes(&body, &server_random, SSL3_RANDOM_SIZE) ||
128 !CBS_get_u8_length_prefixed(&body, &session_id) ||
129 !CBS_mem_equal(&session_id, hs->session_id, hs->session_id_len) ||
130 !CBS_get_u16(&body, &cipher_suite) ||
131 !CBS_get_u8(&body, &compression_method) ||
132 compression_method != 0 ||
133 !CBS_get_u16_length_prefixed(&body, &extensions) ||
134 CBS_len(&extensions) == 0 ||
135 CBS_len(&body) != 0) {
136 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
137 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
138 return ssl_hs_error;
139 }
140
141 if (!CBS_mem_equal(&server_random, kHelloRetryRequest, SSL3_RANDOM_SIZE)) {
142 hs->tls13_state = state_read_server_hello;
143 return ssl_hs_ok;
144 }
145
146 const SSL_CIPHER *cipher = SSL_get_cipher_by_value(cipher_suite);
147 // Check if the cipher is a TLS 1.3 cipher.
148 if (cipher == NULL ||
149 SSL_CIPHER_get_min_version(cipher) > ssl_protocol_version(ssl) ||
150 SSL_CIPHER_get_max_version(cipher) < ssl_protocol_version(ssl)) {
151 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CIPHER_RETURNED);
152 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
153 return ssl_hs_error;
154 }
155
156 hs->new_cipher = cipher;
157
158 if (!hs->transcript.InitHash(ssl_protocol_version(ssl), hs->new_cipher) ||
159 !hs->transcript.UpdateForHelloRetryRequest()) {
160 return ssl_hs_error;
161 }
162
163
164 bool have_cookie, have_key_share, have_supported_versions;
165 CBS cookie, key_share, supported_versions;
166 SSL_EXTENSION_TYPE ext_types[] = {
167 {TLSEXT_TYPE_key_share, &have_key_share, &key_share},
168 {TLSEXT_TYPE_cookie, &have_cookie, &cookie},
169 {TLSEXT_TYPE_supported_versions, &have_supported_versions,
170 &supported_versions},
171 };
172
173 uint8_t alert = SSL_AD_DECODE_ERROR;
174 if (!ssl_parse_extensions(&extensions, &alert, ext_types,
175 OPENSSL_ARRAY_SIZE(ext_types),
176 0 /* reject unknown */)) {
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 OPENSSL_ARRAY_SIZE(ext_types),
342 0 /* reject unknown */)) {
343 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
344 return ssl_hs_error;
345 }
346
347 // Recheck supported_versions, in case this is the second ServerHello.
348 uint16_t version;
349 if (!have_supported_versions ||
350 !CBS_get_u16(&supported_versions, &version) ||
351 version != ssl->version) {
352 OPENSSL_PUT_ERROR(SSL, SSL_R_SECOND_SERVERHELLO_VERSION_MISMATCH);
353 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
354 return ssl_hs_error;
355 }
356
357 alert = SSL_AD_DECODE_ERROR;
358 if (have_pre_shared_key) {
359 if (ssl->session == NULL) {
360 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION);
361 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNSUPPORTED_EXTENSION);
362 return ssl_hs_error;
363 }
364
365 if (!ssl_ext_pre_shared_key_parse_serverhello(hs, &alert,
366 &pre_shared_key)) {
367 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
368 return ssl_hs_error;
369 }
370
371 if (ssl->session->ssl_version != ssl->version) {
372 OPENSSL_PUT_ERROR(SSL, SSL_R_OLD_SESSION_VERSION_NOT_RETURNED);
373 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
374 return ssl_hs_error;
375 }
376
377 if (ssl->session->cipher->algorithm_prf != cipher->algorithm_prf) {
378 OPENSSL_PUT_ERROR(SSL, SSL_R_OLD_SESSION_PRF_HASH_MISMATCH);
379 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
380 return ssl_hs_error;
381 }
382
383 if (!ssl_session_is_context_valid(hs, ssl->session.get())) {
384 // This is actually a client application bug.
385 OPENSSL_PUT_ERROR(SSL,
386 SSL_R_ATTEMPT_TO_REUSE_SESSION_IN_DIFFERENT_CONTEXT);
387 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
388 return ssl_hs_error;
389 }
390
391 ssl->s3->session_reused = true;
392 // Only authentication information carries over in TLS 1.3.
393 hs->new_session =
394 SSL_SESSION_dup(ssl->session.get(), SSL_SESSION_DUP_AUTH_ONLY);
395 if (!hs->new_session) {
396 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
397 return ssl_hs_error;
398 }
399 ssl_set_session(ssl, NULL);
400
401 // Resumption incorporates fresh key material, so refresh the timeout.
402 ssl_session_renew_timeout(ssl, hs->new_session.get(),
403 ssl->session_ctx->session_psk_dhe_timeout);
404 } else if (!ssl_get_new_session(hs, 0)) {
405 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
406 return ssl_hs_error;
407 }
408
409 hs->new_session->cipher = cipher;
410 hs->new_cipher = cipher;
411
412 size_t hash_len =
413 EVP_MD_size(ssl_get_handshake_digest(ssl_protocol_version(ssl), cipher));
414
415 // Set up the key schedule and incorporate the PSK into the running secret.
416 if (ssl->s3->session_reused) {
417 if (!tls13_init_key_schedule(
418 hs, MakeConstSpan(hs->new_session->master_key,
419 hs->new_session->master_key_length))) {
420 return ssl_hs_error;
421 }
422 } else if (!tls13_init_key_schedule(hs, MakeConstSpan(kZeroes, hash_len))) {
423 return ssl_hs_error;
424 }
425
426 if (!have_key_share) {
427 // We do not support psk_ke and thus always require a key share.
428 OPENSSL_PUT_ERROR(SSL, SSL_R_MISSING_KEY_SHARE);
429 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_MISSING_EXTENSION);
430 return ssl_hs_error;
431 }
432
433 // Resolve ECDHE and incorporate it into the secret.
434 Array<uint8_t> dhe_secret;
435 alert = SSL_AD_DECODE_ERROR;
436 if (!ssl_ext_key_share_parse_serverhello(hs, &dhe_secret, &alert,
437 &key_share)) {
438 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
439 return ssl_hs_error;
440 }
441
442 if (!tls13_advance_key_schedule(hs, dhe_secret) ||
443 !ssl_hash_message(hs, msg) ||
444 !tls13_derive_handshake_secrets(hs)) {
445 return ssl_hs_error;
446 }
447
448 // If currently sending early data over TCP, we defer installing client
449 // traffic keys to when the early data stream is closed. See
450 // |close_early_data|. Note if the server has already rejected 0-RTT via
451 // HelloRetryRequest, |in_early_data| is already false.
452 if (!hs->in_early_data || ssl->quic_method != nullptr) {
453 if (!tls13_set_traffic_key(ssl, ssl_encryption_handshake, evp_aead_seal,
454 hs->new_session.get(),
455 hs->client_handshake_secret())) {
456 return ssl_hs_error;
457 }
458 }
459
460 if (!tls13_set_traffic_key(ssl, ssl_encryption_handshake, evp_aead_open,
461 hs->new_session.get(),
462 hs->server_handshake_secret())) {
463 return ssl_hs_error;
464 }
465
466 ssl->method->next_message(ssl);
467 hs->tls13_state = state_read_encrypted_extensions;
468 return ssl_hs_ok;
469 }
470
do_read_encrypted_extensions(SSL_HANDSHAKE * hs)471 static enum ssl_hs_wait_t do_read_encrypted_extensions(SSL_HANDSHAKE *hs) {
472 SSL *const ssl = hs->ssl;
473 SSLMessage msg;
474 if (!ssl->method->get_message(ssl, &msg)) {
475 return ssl_hs_read_message;
476 }
477 if (!ssl_check_message_type(ssl, msg, SSL3_MT_ENCRYPTED_EXTENSIONS)) {
478 return ssl_hs_error;
479 }
480
481 CBS body = msg.body;
482 if (!ssl_parse_serverhello_tlsext(hs, &body)) {
483 OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT);
484 return ssl_hs_error;
485 }
486 if (CBS_len(&body) != 0) {
487 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
488 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
489 return ssl_hs_error;
490 }
491
492 // Store the negotiated ALPN in the session.
493 if (!hs->new_session->early_alpn.CopyFrom(ssl->s3->alpn_selected)) {
494 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
495 return ssl_hs_error;
496 }
497
498 if (ssl->s3->early_data_accepted) {
499 if (hs->early_session->cipher != hs->new_session->cipher) {
500 OPENSSL_PUT_ERROR(SSL, SSL_R_CIPHER_MISMATCH_ON_EARLY_DATA);
501 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
502 return ssl_hs_error;
503 }
504 if (MakeConstSpan(hs->early_session->early_alpn) !=
505 ssl->s3->alpn_selected) {
506 OPENSSL_PUT_ERROR(SSL, SSL_R_ALPN_MISMATCH_ON_EARLY_DATA);
507 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
508 return ssl_hs_error;
509 }
510 if (ssl->s3->channel_id_valid || ssl->s3->token_binding_negotiated) {
511 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION_ON_EARLY_DATA);
512 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
513 return ssl_hs_error;
514 }
515 }
516
517 if (!ssl_hash_message(hs, msg)) {
518 return ssl_hs_error;
519 }
520
521 ssl->method->next_message(ssl);
522 hs->tls13_state = state_read_certificate_request;
523 if (hs->in_early_data && !ssl->s3->early_data_accepted) {
524 if (!close_early_data(hs, ssl_encryption_handshake)) {
525 return ssl_hs_error;
526 }
527 return ssl_hs_early_data_rejected;
528 }
529 return ssl_hs_ok;
530 }
531
do_read_certificate_request(SSL_HANDSHAKE * hs)532 static enum ssl_hs_wait_t do_read_certificate_request(SSL_HANDSHAKE *hs) {
533 SSL *const ssl = hs->ssl;
534 // CertificateRequest may only be sent in non-resumption handshakes.
535 if (ssl->s3->session_reused) {
536 if (ssl->ctx->reverify_on_resume && !ssl->s3->early_data_accepted) {
537 hs->tls13_state = state_server_certificate_reverify;
538 return ssl_hs_ok;
539 }
540 hs->tls13_state = state_read_server_finished;
541 return ssl_hs_ok;
542 }
543
544 SSLMessage msg;
545 if (!ssl->method->get_message(ssl, &msg)) {
546 return ssl_hs_read_message;
547 }
548
549 // CertificateRequest is optional.
550 if (msg.type != SSL3_MT_CERTIFICATE_REQUEST) {
551 hs->tls13_state = state_read_server_certificate;
552 return ssl_hs_ok;
553 }
554
555
556 bool have_sigalgs = false, have_ca = false;
557 CBS sigalgs, ca;
558 const SSL_EXTENSION_TYPE ext_types[] = {
559 {TLSEXT_TYPE_signature_algorithms, &have_sigalgs, &sigalgs},
560 {TLSEXT_TYPE_certificate_authorities, &have_ca, &ca},
561 };
562
563 CBS body = msg.body, context, extensions, supported_signature_algorithms;
564 uint8_t alert = SSL_AD_DECODE_ERROR;
565 if (!CBS_get_u8_length_prefixed(&body, &context) ||
566 // The request context is always empty during the handshake.
567 CBS_len(&context) != 0 ||
568 !CBS_get_u16_length_prefixed(&body, &extensions) ||
569 CBS_len(&body) != 0 ||
570 !ssl_parse_extensions(&extensions, &alert, ext_types,
571 OPENSSL_ARRAY_SIZE(ext_types),
572 1 /* accept unknown */) ||
573 (have_ca && CBS_len(&ca) == 0) ||
574 !have_sigalgs ||
575 !CBS_get_u16_length_prefixed(&sigalgs,
576 &supported_signature_algorithms) ||
577 !tls1_parse_peer_sigalgs(hs, &supported_signature_algorithms)) {
578 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
579 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
580 return ssl_hs_error;
581 }
582
583 if (have_ca) {
584 hs->ca_names = ssl_parse_client_CA_list(ssl, &alert, &ca);
585 if (!hs->ca_names) {
586 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
587 return ssl_hs_error;
588 }
589 } else {
590 hs->ca_names.reset(sk_CRYPTO_BUFFER_new_null());
591 if (!hs->ca_names) {
592 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
593 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
594 return ssl_hs_error;
595 }
596 }
597
598 hs->cert_request = true;
599 ssl->ctx->x509_method->hs_flush_cached_ca_names(hs);
600
601 if (!ssl_hash_message(hs, msg)) {
602 return ssl_hs_error;
603 }
604
605 ssl->method->next_message(ssl);
606 hs->tls13_state = state_read_server_certificate;
607 return ssl_hs_ok;
608 }
609
do_read_server_certificate(SSL_HANDSHAKE * hs)610 static enum ssl_hs_wait_t do_read_server_certificate(SSL_HANDSHAKE *hs) {
611 SSL *const ssl = hs->ssl;
612 SSLMessage msg;
613 if (!ssl->method->get_message(ssl, &msg)) {
614 return ssl_hs_read_message;
615 }
616
617 if (msg.type != SSL3_MT_COMPRESSED_CERTIFICATE &&
618 !ssl_check_message_type(ssl, msg, SSL3_MT_CERTIFICATE)) {
619 return ssl_hs_error;
620 }
621
622 if (!tls13_process_certificate(hs, msg, false /* certificate required */) ||
623 !ssl_hash_message(hs, msg)) {
624 return ssl_hs_error;
625 }
626
627 ssl->method->next_message(ssl);
628 hs->tls13_state = state_read_server_certificate_verify;
629 return ssl_hs_ok;
630 }
631
do_read_server_certificate_verify(SSL_HANDSHAKE * hs)632 static enum ssl_hs_wait_t do_read_server_certificate_verify(
633 SSL_HANDSHAKE *hs) {
634 SSL *const ssl = hs->ssl;
635 SSLMessage msg;
636 if (!ssl->method->get_message(ssl, &msg)) {
637 return ssl_hs_read_message;
638 }
639 switch (ssl_verify_peer_cert(hs)) {
640 case ssl_verify_ok:
641 break;
642 case ssl_verify_invalid:
643 return ssl_hs_error;
644 case ssl_verify_retry:
645 hs->tls13_state = state_read_server_certificate_verify;
646 return ssl_hs_certificate_verify;
647 }
648
649 if (!ssl_check_message_type(ssl, msg, SSL3_MT_CERTIFICATE_VERIFY) ||
650 !tls13_process_certificate_verify(hs, msg) ||
651 !ssl_hash_message(hs, msg)) {
652 return ssl_hs_error;
653 }
654
655 ssl->method->next_message(ssl);
656 hs->tls13_state = state_read_server_finished;
657 return ssl_hs_ok;
658 }
659
do_server_certificate_reverify(SSL_HANDSHAKE * hs)660 static enum ssl_hs_wait_t do_server_certificate_reverify(
661 SSL_HANDSHAKE *hs) {
662 switch (ssl_reverify_peer_cert(hs, /*send_alert=*/true)) {
663 case ssl_verify_ok:
664 break;
665 case ssl_verify_invalid:
666 return ssl_hs_error;
667 case ssl_verify_retry:
668 hs->tls13_state = state_server_certificate_reverify;
669 return ssl_hs_certificate_verify;
670 }
671 hs->tls13_state = state_read_server_finished;
672 return ssl_hs_ok;
673 }
674
do_read_server_finished(SSL_HANDSHAKE * hs)675 static enum ssl_hs_wait_t do_read_server_finished(SSL_HANDSHAKE *hs) {
676 SSL *const ssl = hs->ssl;
677 SSLMessage msg;
678 if (!ssl->method->get_message(ssl, &msg)) {
679 return ssl_hs_read_message;
680 }
681 if (!ssl_check_message_type(ssl, msg, SSL3_MT_FINISHED) ||
682 !tls13_process_finished(hs, msg, false /* don't use saved value */) ||
683 !ssl_hash_message(hs, msg) ||
684 // Update the secret to the master secret and derive traffic keys.
685 !tls13_advance_key_schedule(
686 hs, MakeConstSpan(kZeroes, hs->transcript.DigestLen())) ||
687 !tls13_derive_application_secrets(hs)) {
688 return ssl_hs_error;
689 }
690
691 // Finished should be the end of the flight.
692 if (ssl->method->has_unprocessed_handshake_data(ssl)) {
693 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
694 OPENSSL_PUT_ERROR(SSL, SSL_R_EXCESS_HANDSHAKE_DATA);
695 return ssl_hs_error;
696 }
697
698 ssl->method->next_message(ssl);
699 hs->tls13_state = state_send_end_of_early_data;
700 return ssl_hs_ok;
701 }
702
do_send_end_of_early_data(SSL_HANDSHAKE * hs)703 static enum ssl_hs_wait_t do_send_end_of_early_data(SSL_HANDSHAKE *hs) {
704 SSL *const ssl = hs->ssl;
705
706 if (ssl->s3->early_data_accepted) {
707 // QUIC omits the EndOfEarlyData message. See draft-ietf-quic-tls-22,
708 // section 8.3.
709 if (ssl->quic_method == nullptr) {
710 ScopedCBB cbb;
711 CBB body;
712 if (!ssl->method->init_message(ssl, cbb.get(), &body,
713 SSL3_MT_END_OF_EARLY_DATA) ||
714 !ssl_add_message_cbb(ssl, cbb.get())) {
715 return ssl_hs_error;
716 }
717 }
718
719 if (!close_early_data(hs, ssl_encryption_handshake)) {
720 return ssl_hs_error;
721 }
722 }
723
724 hs->tls13_state = state_send_client_certificate;
725 return ssl_hs_ok;
726 }
727
do_send_client_certificate(SSL_HANDSHAKE * hs)728 static enum ssl_hs_wait_t do_send_client_certificate(SSL_HANDSHAKE *hs) {
729 SSL *const ssl = hs->ssl;
730
731 // The peer didn't request a certificate.
732 if (!hs->cert_request) {
733 hs->tls13_state = state_complete_second_flight;
734 return ssl_hs_ok;
735 }
736
737 // Call cert_cb to update the certificate.
738 if (hs->config->cert->cert_cb != NULL) {
739 int rv = hs->config->cert->cert_cb(ssl, hs->config->cert->cert_cb_arg);
740 if (rv == 0) {
741 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
742 OPENSSL_PUT_ERROR(SSL, SSL_R_CERT_CB_ERROR);
743 return ssl_hs_error;
744 }
745 if (rv < 0) {
746 hs->tls13_state = state_send_client_certificate;
747 return ssl_hs_x509_lookup;
748 }
749 }
750
751 if (!ssl_on_certificate_selected(hs) ||
752 !tls13_add_certificate(hs)) {
753 return ssl_hs_error;
754 }
755
756 hs->tls13_state = state_send_client_certificate_verify;
757 return ssl_hs_ok;
758 }
759
do_send_client_certificate_verify(SSL_HANDSHAKE * hs)760 static enum ssl_hs_wait_t do_send_client_certificate_verify(SSL_HANDSHAKE *hs) {
761 // Don't send CertificateVerify if there is no certificate.
762 if (!ssl_has_certificate(hs)) {
763 hs->tls13_state = state_complete_second_flight;
764 return ssl_hs_ok;
765 }
766
767 switch (tls13_add_certificate_verify(hs)) {
768 case ssl_private_key_success:
769 hs->tls13_state = state_complete_second_flight;
770 return ssl_hs_ok;
771
772 case ssl_private_key_retry:
773 hs->tls13_state = state_send_client_certificate_verify;
774 return ssl_hs_private_key_operation;
775
776 case ssl_private_key_failure:
777 return ssl_hs_error;
778 }
779
780 assert(0);
781 return ssl_hs_error;
782 }
783
do_complete_second_flight(SSL_HANDSHAKE * hs)784 static enum ssl_hs_wait_t do_complete_second_flight(SSL_HANDSHAKE *hs) {
785 SSL *const ssl = hs->ssl;
786
787 // Send a Channel ID assertion if necessary.
788 if (ssl->s3->channel_id_valid) {
789 if (!ssl_do_channel_id_callback(hs)) {
790 hs->tls13_state = state_complete_second_flight;
791 return ssl_hs_error;
792 }
793
794 if (hs->config->channel_id_private == NULL) {
795 return ssl_hs_channel_id_lookup;
796 }
797
798 ScopedCBB cbb;
799 CBB body;
800 if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_CHANNEL_ID) ||
801 !tls1_write_channel_id(hs, &body) ||
802 !ssl_add_message_cbb(ssl, cbb.get())) {
803 return ssl_hs_error;
804 }
805 }
806
807 // Send a Finished message.
808 if (!tls13_add_finished(hs)) {
809 return ssl_hs_error;
810 }
811
812 // Derive the final keys and enable them.
813 if (!tls13_set_traffic_key(ssl, ssl_encryption_application, evp_aead_seal,
814 hs->new_session.get(),
815 hs->client_traffic_secret_0()) ||
816 !tls13_set_traffic_key(ssl, ssl_encryption_application, evp_aead_open,
817 hs->new_session.get(),
818 hs->server_traffic_secret_0()) ||
819 !tls13_derive_resumption_secret(hs)) {
820 return ssl_hs_error;
821 }
822
823 hs->tls13_state = state_done;
824 return ssl_hs_flush;
825 }
826
tls13_client_handshake(SSL_HANDSHAKE * hs)827 enum ssl_hs_wait_t tls13_client_handshake(SSL_HANDSHAKE *hs) {
828 while (hs->tls13_state != state_done) {
829 enum ssl_hs_wait_t ret = ssl_hs_error;
830 enum client_hs_state_t state =
831 static_cast<enum client_hs_state_t>(hs->tls13_state);
832 switch (state) {
833 case state_read_hello_retry_request:
834 ret = do_read_hello_retry_request(hs);
835 break;
836 case state_send_second_client_hello:
837 ret = do_send_second_client_hello(hs);
838 break;
839 case state_read_server_hello:
840 ret = do_read_server_hello(hs);
841 break;
842 case state_read_encrypted_extensions:
843 ret = do_read_encrypted_extensions(hs);
844 break;
845 case state_read_certificate_request:
846 ret = do_read_certificate_request(hs);
847 break;
848 case state_read_server_certificate:
849 ret = do_read_server_certificate(hs);
850 break;
851 case state_read_server_certificate_verify:
852 ret = do_read_server_certificate_verify(hs);
853 break;
854 case state_server_certificate_reverify:
855 ret = do_server_certificate_reverify(hs);
856 break;
857 case state_read_server_finished:
858 ret = do_read_server_finished(hs);
859 break;
860 case state_send_end_of_early_data:
861 ret = do_send_end_of_early_data(hs);
862 break;
863 case state_send_client_certificate:
864 ret = do_send_client_certificate(hs);
865 break;
866 case state_send_client_certificate_verify:
867 ret = do_send_client_certificate_verify(hs);
868 break;
869 case state_complete_second_flight:
870 ret = do_complete_second_flight(hs);
871 break;
872 case state_done:
873 ret = ssl_hs_ok;
874 break;
875 }
876
877 if (hs->tls13_state != state) {
878 ssl_do_info_callback(hs->ssl, SSL_CB_CONNECT_LOOP, 1);
879 }
880
881 if (ret != ssl_hs_ok) {
882 return ret;
883 }
884 }
885
886 return ssl_hs_ok;
887 }
888
tls13_client_handshake_state(SSL_HANDSHAKE * hs)889 const char *tls13_client_handshake_state(SSL_HANDSHAKE *hs) {
890 enum client_hs_state_t state =
891 static_cast<enum client_hs_state_t>(hs->tls13_state);
892 switch (state) {
893 case state_read_hello_retry_request:
894 return "TLS 1.3 client read_hello_retry_request";
895 case state_send_second_client_hello:
896 return "TLS 1.3 client send_second_client_hello";
897 case state_read_server_hello:
898 return "TLS 1.3 client read_server_hello";
899 case state_read_encrypted_extensions:
900 return "TLS 1.3 client read_encrypted_extensions";
901 case state_read_certificate_request:
902 return "TLS 1.3 client read_certificate_request";
903 case state_read_server_certificate:
904 return "TLS 1.3 client read_server_certificate";
905 case state_read_server_certificate_verify:
906 return "TLS 1.3 client read_server_certificate_verify";
907 case state_server_certificate_reverify:
908 return "TLS 1.3 client server_certificate_reverify";
909 case state_read_server_finished:
910 return "TLS 1.3 client read_server_finished";
911 case state_send_end_of_early_data:
912 return "TLS 1.3 client send_end_of_early_data";
913 case state_send_client_certificate:
914 return "TLS 1.3 client send_client_certificate";
915 case state_send_client_certificate_verify:
916 return "TLS 1.3 client send_client_certificate_verify";
917 case state_complete_second_flight:
918 return "TLS 1.3 client complete_second_flight";
919 case state_done:
920 return "TLS 1.3 client done";
921 }
922
923 return "TLS 1.3 client unknown";
924 }
925
tls13_process_new_session_ticket(SSL * ssl,const SSLMessage & msg)926 bool tls13_process_new_session_ticket(SSL *ssl, const SSLMessage &msg) {
927 if (ssl->s3->write_shutdown != ssl_shutdown_none) {
928 // Ignore tickets on shutdown. Callers tend to indiscriminately call
929 // |SSL_shutdown| before destroying an |SSL|, at which point calling the new
930 // session callback may be confusing.
931 return true;
932 }
933
934 CBS body = msg.body;
935 UniquePtr<SSL_SESSION> session = tls13_create_session_with_ticket(ssl, &body);
936 if (!session) {
937 return false;
938 }
939
940 if ((ssl->session_ctx->session_cache_mode & SSL_SESS_CACHE_CLIENT) &&
941 ssl->session_ctx->new_session_cb != NULL &&
942 ssl->session_ctx->new_session_cb(ssl, session.get())) {
943 // |new_session_cb|'s return value signals that it took ownership.
944 session.release();
945 }
946
947 return true;
948 }
949
tls13_create_session_with_ticket(SSL * ssl,CBS * body)950 UniquePtr<SSL_SESSION> tls13_create_session_with_ticket(SSL *ssl, CBS *body) {
951 UniquePtr<SSL_SESSION> session = SSL_SESSION_dup(
952 ssl->s3->established_session.get(), SSL_SESSION_INCLUDE_NONAUTH);
953 if (!session) {
954 return nullptr;
955 }
956
957 ssl_session_rebase_time(ssl, session.get());
958
959 uint32_t server_timeout;
960 CBS ticket_nonce, ticket, extensions;
961 if (!CBS_get_u32(body, &server_timeout) ||
962 !CBS_get_u32(body, &session->ticket_age_add) ||
963 !CBS_get_u8_length_prefixed(body, &ticket_nonce) ||
964 !CBS_get_u16_length_prefixed(body, &ticket) ||
965 !session->ticket.CopyFrom(ticket) ||
966 !CBS_get_u16_length_prefixed(body, &extensions) ||
967 CBS_len(body) != 0) {
968 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
969 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
970 return nullptr;
971 }
972
973 // Cap the renewable lifetime by the server advertised value. This avoids
974 // wasting bandwidth on 0-RTT when we know the server will reject it.
975 if (session->timeout > server_timeout) {
976 session->timeout = server_timeout;
977 }
978
979 if (!tls13_derive_session_psk(session.get(), ticket_nonce)) {
980 return nullptr;
981 }
982
983 // Parse out the extensions.
984 bool have_early_data = false;
985 CBS early_data;
986 const SSL_EXTENSION_TYPE ext_types[] = {
987 {TLSEXT_TYPE_early_data, &have_early_data, &early_data},
988 };
989
990 uint8_t alert = SSL_AD_DECODE_ERROR;
991 if (!ssl_parse_extensions(&extensions, &alert, ext_types,
992 OPENSSL_ARRAY_SIZE(ext_types),
993 1 /* ignore unknown */)) {
994 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
995 return nullptr;
996 }
997
998 if (have_early_data) {
999 if (!CBS_get_u32(&early_data, &session->ticket_max_early_data) ||
1000 CBS_len(&early_data) != 0) {
1001 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
1002 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1003 return nullptr;
1004 }
1005
1006 // QUIC does not use the max_early_data_size parameter and always sets it to
1007 // a fixed value. See draft-ietf-quic-tls-22, section 4.5.
1008 if (ssl->quic_method != nullptr &&
1009 session->ticket_max_early_data != 0xffffffff) {
1010 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
1011 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
1012 return nullptr;
1013 }
1014 }
1015
1016 // Generate a session ID for this session. Some callers expect all sessions to
1017 // have a session ID.
1018 SHA256(CBS_data(&ticket), CBS_len(&ticket), session->session_id);
1019 session->session_id_length = SHA256_DIGEST_LENGTH;
1020
1021 session->ticket_age_add_valid = true;
1022 session->not_resumable = false;
1023
1024 return session;
1025 }
1026
1027 BSSL_NAMESPACE_END
1028