1 /* Copyright (c) 2016, Google Inc.
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.
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. */
15 #include <openssl/ssl.h>
22 #include <openssl/bytestring.h>
23 #include <openssl/err.h>
24 #include <openssl/hkdf.h>
25 #include <openssl/mem.h>
26 #include <openssl/stack.h>
27 #include <openssl/x509.h>
29 #include "../crypto/internal.h"
35 // kMaxKeyUpdates is the number of consecutive KeyUpdates that will be
36 // processed. Without this limit an attacker could force unbounded processing
37 // without being able to return application data.
38 static const uint8_t kMaxKeyUpdates = 32;
40 const uint8_t kHelloRetryRequest[SSL3_RANDOM_SIZE] = {
41 0xcf, 0x21, 0xad, 0x74, 0xe5, 0x9a, 0x61, 0x11, 0xbe, 0x1d, 0x8c,
42 0x02, 0x1e, 0x65, 0xb8, 0x91, 0xc2, 0xa2, 0x11, 0x16, 0x7a, 0xbb,
43 0x8c, 0x5e, 0x07, 0x9e, 0x09, 0xe2, 0xc8, 0xa8, 0x33, 0x9c,
46 // This value was selected by truncating the SHA-256 hash of "Draft TLS 1.3
47 // Downgrade" to 8 bytes:
49 // echo -n 'Draft TLS 1.3 Downgrade' | sha256sum | head -c 16
50 const uint8_t kDraftDowngradeRandom[8] = {0x95, 0xb9, 0x9f, 0x87,
51 0x22, 0xfe, 0x9b, 0x64};
54 bool tls13_get_cert_verify_signature_input(
55 SSL_HANDSHAKE *hs, Array<uint8_t> *out,
56 enum ssl_cert_verify_context_t cert_verify_context) {
58 if (!CBB_init(cbb.get(), 64 + 33 + 1 + 2 * EVP_MAX_MD_SIZE)) {
59 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
63 for (size_t i = 0; i < 64; i++) {
64 if (!CBB_add_u8(cbb.get(), 0x20)) {
65 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
70 Span<const char> context;
71 if (cert_verify_context == ssl_cert_verify_server) {
72 static const char kContext[] = "TLS 1.3, server CertificateVerify";
74 } else if (cert_verify_context == ssl_cert_verify_client) {
75 static const char kContext[] = "TLS 1.3, client CertificateVerify";
77 } else if (cert_verify_context == ssl_cert_verify_channel_id) {
78 static const char kContext[] = "TLS 1.3, Channel ID";
81 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
85 // Note |context| includes the NUL byte separator.
86 if (!CBB_add_bytes(cbb.get(),
87 reinterpret_cast<const uint8_t *>(context.data()),
89 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
93 uint8_t context_hash[EVP_MAX_MD_SIZE];
94 size_t context_hash_len;
95 if (!hs->transcript.GetHash(context_hash, &context_hash_len) ||
96 !CBB_add_bytes(cbb.get(), context_hash, context_hash_len) ||
97 !CBBFinishArray(cbb.get(), out)) {
98 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
105 int tls13_process_certificate(SSL_HANDSHAKE *hs, const SSLMessage &msg,
106 int allow_anonymous) {
107 SSL *const ssl = hs->ssl;
108 CBS body = msg.body, context, certificate_list;
109 if (!CBS_get_u8_length_prefixed(&body, &context) ||
110 CBS_len(&context) != 0 ||
111 !CBS_get_u24_length_prefixed(&body, &certificate_list) ||
112 CBS_len(&body) != 0) {
113 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
114 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
118 UniquePtr<STACK_OF(CRYPTO_BUFFER)> certs(sk_CRYPTO_BUFFER_new_null());
120 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
121 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
125 const bool retain_sha256 =
126 ssl->server && ssl->retain_only_sha256_of_client_certs;
127 UniquePtr<EVP_PKEY> pkey;
128 while (CBS_len(&certificate_list) > 0) {
129 CBS certificate, extensions;
130 if (!CBS_get_u24_length_prefixed(&certificate_list, &certificate) ||
131 !CBS_get_u16_length_prefixed(&certificate_list, &extensions) ||
132 CBS_len(&certificate) == 0) {
133 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
134 OPENSSL_PUT_ERROR(SSL, SSL_R_CERT_LENGTH_MISMATCH);
138 if (sk_CRYPTO_BUFFER_num(certs.get()) == 0) {
139 pkey = ssl_cert_parse_pubkey(&certificate);
141 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
142 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
145 // TLS 1.3 always uses certificate keys for signing thus the correct
146 // keyUsage is enforced.
147 if (!ssl_cert_check_digital_signature_key_usage(&certificate)) {
148 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
153 // Retain the hash of the leaf certificate if requested.
154 SHA256(CBS_data(&certificate), CBS_len(&certificate),
155 hs->new_session->peer_sha256);
159 UniquePtr<CRYPTO_BUFFER> buf(
160 CRYPTO_BUFFER_new_from_CBS(&certificate, ssl->ctx->pool));
162 !PushToStack(certs.get(), std::move(buf))) {
163 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
164 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
168 // Parse out the extensions.
169 bool have_status_request = false, have_sct = false;
170 CBS status_request, sct;
171 const SSL_EXTENSION_TYPE ext_types[] = {
172 {TLSEXT_TYPE_status_request, &have_status_request, &status_request},
173 {TLSEXT_TYPE_certificate_timestamp, &have_sct, &sct},
176 uint8_t alert = SSL_AD_DECODE_ERROR;
177 if (!ssl_parse_extensions(&extensions, &alert, ext_types,
178 OPENSSL_ARRAY_SIZE(ext_types),
179 0 /* reject unknown */)) {
180 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
184 // All Certificate extensions are parsed, but only the leaf extensions are
186 if (have_status_request) {
187 if (ssl->server || !ssl->ocsp_stapling_enabled) {
188 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION);
189 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNSUPPORTED_EXTENSION);
195 if (!CBS_get_u8(&status_request, &status_type) ||
196 status_type != TLSEXT_STATUSTYPE_ocsp ||
197 !CBS_get_u24_length_prefixed(&status_request, &ocsp_response) ||
198 CBS_len(&ocsp_response) == 0 ||
199 CBS_len(&status_request) != 0) {
200 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
204 if (sk_CRYPTO_BUFFER_num(certs.get()) == 1) {
205 CRYPTO_BUFFER_free(hs->new_session->ocsp_response);
206 hs->new_session->ocsp_response =
207 CRYPTO_BUFFER_new_from_CBS(&ocsp_response, ssl->ctx->pool);
208 if (hs->new_session->ocsp_response == nullptr) {
209 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
216 if (ssl->server || !ssl->signed_cert_timestamps_enabled) {
217 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION);
218 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNSUPPORTED_EXTENSION);
222 if (!ssl_is_sct_list_valid(&sct)) {
223 OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_PARSING_EXTENSION);
224 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
228 if (sk_CRYPTO_BUFFER_num(certs.get()) == 1) {
229 CRYPTO_BUFFER_free(hs->new_session->signed_cert_timestamp_list);
230 hs->new_session->signed_cert_timestamp_list =
231 CRYPTO_BUFFER_new_from_CBS(&sct, ssl->ctx->pool);
232 if (hs->new_session->signed_cert_timestamp_list == nullptr) {
233 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
240 // Store a null certificate list rather than an empty one if the peer didn't
241 // send certificates.
242 if (sk_CRYPTO_BUFFER_num(certs.get()) == 0) {
246 hs->peer_pubkey = std::move(pkey);
248 sk_CRYPTO_BUFFER_pop_free(hs->new_session->certs, CRYPTO_BUFFER_free);
249 hs->new_session->certs = certs.release();
251 if (!ssl->ctx->x509_method->session_cache_objects(hs->new_session.get())) {
252 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
253 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
257 if (sk_CRYPTO_BUFFER_num(hs->new_session->certs) == 0) {
258 if (!allow_anonymous) {
259 OPENSSL_PUT_ERROR(SSL, SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
260 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_CERTIFICATE_REQUIRED);
264 // OpenSSL returns X509_V_OK when no certificates are requested. This is
265 // classed by them as a bug, but it's assumed by at least NGINX.
266 hs->new_session->verify_result = X509_V_OK;
268 // No certificate, so nothing more to do.
272 hs->new_session->peer_sha256_valid = retain_sha256;
276 int tls13_process_certificate_verify(SSL_HANDSHAKE *hs, const SSLMessage &msg) {
277 SSL *const ssl = hs->ssl;
278 if (hs->peer_pubkey == NULL) {
279 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
283 CBS body = msg.body, signature;
284 uint16_t signature_algorithm;
285 if (!CBS_get_u16(&body, &signature_algorithm) ||
286 !CBS_get_u16_length_prefixed(&body, &signature) ||
287 CBS_len(&body) != 0) {
288 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
289 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
293 uint8_t alert = SSL_AD_DECODE_ERROR;
294 if (!tls12_check_peer_sigalg(ssl, &alert, signature_algorithm)) {
295 ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
298 hs->new_session->peer_signature_algorithm = signature_algorithm;
300 Array<uint8_t> input;
301 if (!tls13_get_cert_verify_signature_input(
303 ssl->server ? ssl_cert_verify_client : ssl_cert_verify_server)) {
304 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
308 bool sig_ok = ssl_public_key_verify(ssl, signature, signature_algorithm,
309 hs->peer_pubkey.get(), input);
310 #if defined(BORINGSSL_UNSAFE_FUZZER_MODE)
315 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SIGNATURE);
316 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
323 int tls13_process_finished(SSL_HANDSHAKE *hs, const SSLMessage &msg,
324 int use_saved_value) {
325 SSL *const ssl = hs->ssl;
326 uint8_t verify_data_buf[EVP_MAX_MD_SIZE];
327 const uint8_t *verify_data;
328 size_t verify_data_len;
329 if (use_saved_value) {
331 verify_data = hs->expected_client_finished;
332 verify_data_len = hs->hash_len;
334 if (!tls13_finished_mac(hs, verify_data_buf, &verify_data_len,
338 verify_data = verify_data_buf;
341 int finished_ok = CBS_mem_equal(&msg.body, verify_data, verify_data_len);
342 #if defined(BORINGSSL_UNSAFE_FUZZER_MODE)
346 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
347 OPENSSL_PUT_ERROR(SSL, SSL_R_DIGEST_CHECK_FAILED);
354 int tls13_add_certificate(SSL_HANDSHAKE *hs) {
355 SSL *const ssl = hs->ssl;
357 CBB body, certificate_list;
358 if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_CERTIFICATE) ||
359 // The request context is always empty in the handshake.
360 !CBB_add_u8(&body, 0) ||
361 !CBB_add_u24_length_prefixed(&body, &certificate_list)) {
362 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
366 if (!ssl_has_certificate(ssl)) {
367 return ssl_add_message_cbb(ssl, cbb.get());
370 CERT *cert = ssl->cert;
371 CRYPTO_BUFFER *leaf_buf = sk_CRYPTO_BUFFER_value(cert->chain, 0);
372 CBB leaf, extensions;
373 if (!CBB_add_u24_length_prefixed(&certificate_list, &leaf) ||
374 !CBB_add_bytes(&leaf, CRYPTO_BUFFER_data(leaf_buf),
375 CRYPTO_BUFFER_len(leaf_buf)) ||
376 !CBB_add_u16_length_prefixed(&certificate_list, &extensions)) {
377 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
381 if (hs->scts_requested && ssl->cert->signed_cert_timestamp_list != NULL) {
383 if (!CBB_add_u16(&extensions, TLSEXT_TYPE_certificate_timestamp) ||
384 !CBB_add_u16_length_prefixed(&extensions, &contents) ||
387 CRYPTO_BUFFER_data(ssl->cert->signed_cert_timestamp_list),
388 CRYPTO_BUFFER_len(ssl->cert->signed_cert_timestamp_list)) ||
389 !CBB_flush(&extensions)) {
390 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
395 if (hs->ocsp_stapling_requested &&
396 ssl->cert->ocsp_response != NULL) {
397 CBB contents, ocsp_response;
398 if (!CBB_add_u16(&extensions, TLSEXT_TYPE_status_request) ||
399 !CBB_add_u16_length_prefixed(&extensions, &contents) ||
400 !CBB_add_u8(&contents, TLSEXT_STATUSTYPE_ocsp) ||
401 !CBB_add_u24_length_prefixed(&contents, &ocsp_response) ||
402 !CBB_add_bytes(&ocsp_response,
403 CRYPTO_BUFFER_data(ssl->cert->ocsp_response),
404 CRYPTO_BUFFER_len(ssl->cert->ocsp_response)) ||
405 !CBB_flush(&extensions)) {
406 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
411 for (size_t i = 1; i < sk_CRYPTO_BUFFER_num(cert->chain); i++) {
412 CRYPTO_BUFFER *cert_buf = sk_CRYPTO_BUFFER_value(cert->chain, i);
414 if (!CBB_add_u24_length_prefixed(&certificate_list, &child) ||
415 !CBB_add_bytes(&child, CRYPTO_BUFFER_data(cert_buf),
416 CRYPTO_BUFFER_len(cert_buf)) ||
417 !CBB_add_u16(&certificate_list, 0 /* no extensions */)) {
418 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
423 return ssl_add_message_cbb(ssl, cbb.get());
426 enum ssl_private_key_result_t tls13_add_certificate_verify(SSL_HANDSHAKE *hs) {
427 SSL *const ssl = hs->ssl;
428 uint16_t signature_algorithm;
429 if (!tls1_choose_signature_algorithm(hs, &signature_algorithm)) {
430 return ssl_private_key_failure;
435 if (!ssl->method->init_message(ssl, cbb.get(), &body,
436 SSL3_MT_CERTIFICATE_VERIFY) ||
437 !CBB_add_u16(&body, signature_algorithm)) {
438 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
439 return ssl_private_key_failure;
444 const size_t max_sig_len = EVP_PKEY_size(hs->local_pubkey.get());
447 if (!CBB_add_u16_length_prefixed(&body, &child) ||
448 !CBB_reserve(&child, &sig, max_sig_len)) {
449 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
450 return ssl_private_key_failure;
454 if (!tls13_get_cert_verify_signature_input(
456 ssl->server ? ssl_cert_verify_server : ssl_cert_verify_client)) {
457 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
458 return ssl_private_key_failure;
461 enum ssl_private_key_result_t sign_result = ssl_private_key_sign(
462 hs, sig, &sig_len, max_sig_len, signature_algorithm, msg);
463 if (sign_result != ssl_private_key_success) {
467 if (!CBB_did_write(&child, sig_len) ||
468 !ssl_add_message_cbb(ssl, cbb.get())) {
469 return ssl_private_key_failure;
472 return ssl_private_key_success;
475 int tls13_add_finished(SSL_HANDSHAKE *hs) {
476 SSL *const ssl = hs->ssl;
477 size_t verify_data_len;
478 uint8_t verify_data[EVP_MAX_MD_SIZE];
480 if (!tls13_finished_mac(hs, verify_data, &verify_data_len, ssl->server)) {
481 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
482 OPENSSL_PUT_ERROR(SSL, SSL_R_DIGEST_CHECK_FAILED);
488 if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_FINISHED) ||
489 !CBB_add_bytes(&body, verify_data, verify_data_len) ||
490 !ssl_add_message_cbb(ssl, cbb.get())) {
497 static int tls13_receive_key_update(SSL *ssl, const SSLMessage &msg) {
499 uint8_t key_update_request;
500 if (!CBS_get_u8(&body, &key_update_request) ||
501 CBS_len(&body) != 0 ||
502 (key_update_request != SSL_KEY_UPDATE_NOT_REQUESTED &&
503 key_update_request != SSL_KEY_UPDATE_REQUESTED)) {
504 OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
505 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
509 if (!tls13_rotate_traffic_key(ssl, evp_aead_open)) {
513 // Acknowledge the KeyUpdate
514 if (key_update_request == SSL_KEY_UPDATE_REQUESTED &&
515 !ssl->s3->key_update_pending) {
518 if (!ssl->method->init_message(ssl, cbb.get(), &body_cbb,
519 SSL3_MT_KEY_UPDATE) ||
520 !CBB_add_u8(&body_cbb, SSL_KEY_UPDATE_NOT_REQUESTED) ||
521 !ssl_add_message_cbb(ssl, cbb.get()) ||
522 !tls13_rotate_traffic_key(ssl, evp_aead_seal)) {
526 // Suppress KeyUpdate acknowledgments until this change is written to the
527 // wire. This prevents us from accumulating write obligations when read and
528 // write progress at different rates. See draft-ietf-tls-tls13-18, section
530 ssl->s3->key_update_pending = true;
536 int tls13_post_handshake(SSL *ssl, const SSLMessage &msg) {
537 if (msg.type == SSL3_MT_KEY_UPDATE) {
538 ssl->s3->key_update_count++;
539 if (ssl->s3->key_update_count > kMaxKeyUpdates) {
540 OPENSSL_PUT_ERROR(SSL, SSL_R_TOO_MANY_KEY_UPDATES);
541 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
545 return tls13_receive_key_update(ssl, msg);
548 ssl->s3->key_update_count = 0;
550 if (msg.type == SSL3_MT_NEW_SESSION_TICKET && !ssl->server) {
551 return tls13_process_new_session_ticket(ssl, msg);
554 ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
555 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);