1 // Copyright 2016 The BoringSSL Authors
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 //     https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 #include <openssl/ssl.h>
16 
17 #include <assert.h>
18 #include <string.h>
19 
20 #include <utility>
21 
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>
28 
29 #include "../crypto/internal.h"
30 #include "internal.h"
31 
32 
33 BSSL_NAMESPACE_BEGIN
34 
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;
39 
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,
44 };
45 
46 // See RFC 8446, section 4.1.3.
47 const uint8_t kTLS12DowngradeRandom[8] = {0x44, 0x4f, 0x57, 0x4e,
48                                           0x47, 0x52, 0x44, 0x00};
49 const uint8_t kTLS13DowngradeRandom[8] = {0x44, 0x4f, 0x57, 0x4e,
50                                           0x47, 0x52, 0x44, 0x01};
51 
52 // This is a non-standard randomly-generated value.
53 const uint8_t kJDK11DowngradeRandom[8] = {0xed, 0xbf, 0xb4, 0xa8,
54                                           0xc2, 0x47, 0x10, 0xff};
55 
tls13_get_cert_verify_signature_input(SSL_HANDSHAKE * hs,Array<uint8_t> * out,enum ssl_cert_verify_context_t cert_verify_context)56 bool tls13_get_cert_verify_signature_input(
57     SSL_HANDSHAKE *hs, Array<uint8_t> *out,
58     enum ssl_cert_verify_context_t cert_verify_context) {
59   ScopedCBB cbb;
60   if (!CBB_init(cbb.get(), 64 + 33 + 1 + 2 * EVP_MAX_MD_SIZE)) {
61     return false;
62   }
63 
64   for (size_t i = 0; i < 64; i++) {
65     if (!CBB_add_u8(cbb.get(), 0x20)) {
66       return false;
67     }
68   }
69 
70   Span<const char> context;
71   if (cert_verify_context == ssl_cert_verify_server) {
72     static const char kContext[] = "TLS 1.3, server CertificateVerify";
73     context = kContext;
74   } else if (cert_verify_context == ssl_cert_verify_client) {
75     static const char kContext[] = "TLS 1.3, client CertificateVerify";
76     context = kContext;
77   } else if (cert_verify_context == ssl_cert_verify_channel_id) {
78     static const char kContext[] = "TLS 1.3, Channel ID";
79     context = kContext;
80   } else {
81     return false;
82   }
83 
84   // Note |context| includes the NUL byte separator.
85   if (!CBB_add_bytes(cbb.get(),
86                      reinterpret_cast<const uint8_t *>(context.data()),
87                      context.size())) {
88     return false;
89   }
90 
91   uint8_t context_hash[EVP_MAX_MD_SIZE];
92   size_t context_hash_len;
93   if (!hs->transcript.GetHash(context_hash, &context_hash_len) ||
94       !CBB_add_bytes(cbb.get(), context_hash, context_hash_len) ||
95       !CBBFinishArray(cbb.get(), out)) {
96     return false;
97   }
98 
99   return true;
100 }
101 
tls13_process_certificate(SSL_HANDSHAKE * hs,const SSLMessage & msg,bool allow_anonymous)102 bool tls13_process_certificate(SSL_HANDSHAKE *hs, const SSLMessage &msg,
103                                bool allow_anonymous) {
104   SSL *const ssl = hs->ssl;
105   CBS body = msg.body;
106   bssl::UniquePtr<CRYPTO_BUFFER> decompressed;
107 
108   if (msg.type == SSL3_MT_COMPRESSED_CERTIFICATE) {
109     CBS compressed;
110     uint16_t alg_id;
111     uint32_t uncompressed_len;
112 
113     if (!CBS_get_u16(&body, &alg_id) ||
114         !CBS_get_u24(&body, &uncompressed_len) ||
115         !CBS_get_u24_length_prefixed(&body, &compressed) ||
116         CBS_len(&body) != 0) {
117       ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
118       OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
119       return false;
120     }
121 
122     if (uncompressed_len > ssl->max_cert_list) {
123       ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
124       OPENSSL_PUT_ERROR(SSL, SSL_R_UNCOMPRESSED_CERT_TOO_LARGE);
125       ERR_add_error_dataf("requested=%u",
126                           static_cast<unsigned>(uncompressed_len));
127       return false;
128     }
129 
130     ssl_cert_decompression_func_t decompress = nullptr;
131     for (const auto &alg : ssl->ctx->cert_compression_algs) {
132       if (alg.alg_id == alg_id) {
133         decompress = alg.decompress;
134         break;
135       }
136     }
137 
138     if (decompress == nullptr) {
139       ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
140       OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_CERT_COMPRESSION_ALG);
141       ERR_add_error_dataf("alg=%d", static_cast<int>(alg_id));
142       return false;
143     }
144 
145     CRYPTO_BUFFER *decompressed_ptr = nullptr;
146     if (!decompress(ssl, &decompressed_ptr, uncompressed_len,
147                     CBS_data(&compressed), CBS_len(&compressed))) {
148       ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
149       OPENSSL_PUT_ERROR(SSL, SSL_R_CERT_DECOMPRESSION_FAILED);
150       ERR_add_error_dataf("alg=%d", static_cast<int>(alg_id));
151       return false;
152     }
153     decompressed.reset(decompressed_ptr);
154 
155     if (CRYPTO_BUFFER_len(decompressed_ptr) != uncompressed_len) {
156       ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
157       OPENSSL_PUT_ERROR(SSL, SSL_R_CERT_DECOMPRESSION_FAILED);
158       ERR_add_error_dataf(
159           "alg=%d got=%u expected=%u", static_cast<int>(alg_id),
160           static_cast<unsigned>(CRYPTO_BUFFER_len(decompressed_ptr)),
161           static_cast<unsigned>(uncompressed_len));
162       return false;
163     }
164 
165     CBS_init(&body, CRYPTO_BUFFER_data(decompressed_ptr),
166              CRYPTO_BUFFER_len(decompressed_ptr));
167   } else {
168     assert(msg.type == SSL3_MT_CERTIFICATE);
169   }
170 
171   CBS context, certificate_list;
172   if (!CBS_get_u8_length_prefixed(&body, &context) ||            //
173       CBS_len(&context) != 0 ||                                  //
174       !CBS_get_u24_length_prefixed(&body, &certificate_list) ||  //
175       CBS_len(&body) != 0) {
176     ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
177     OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
178     return false;
179   }
180 
181   UniquePtr<STACK_OF(CRYPTO_BUFFER)> certs(sk_CRYPTO_BUFFER_new_null());
182   if (!certs) {
183     ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
184     return false;
185   }
186 
187   const bool retain_sha256 =
188       ssl->server && hs->config->retain_only_sha256_of_client_certs;
189   UniquePtr<EVP_PKEY> pkey;
190   while (CBS_len(&certificate_list) > 0) {
191     CBS certificate, extensions;
192     if (!CBS_get_u24_length_prefixed(&certificate_list, &certificate) ||
193         !CBS_get_u16_length_prefixed(&certificate_list, &extensions) ||
194         CBS_len(&certificate) == 0) {
195       ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
196       OPENSSL_PUT_ERROR(SSL, SSL_R_CERT_LENGTH_MISMATCH);
197       return false;
198     }
199 
200     const bool is_leaf = sk_CRYPTO_BUFFER_num(certs.get()) == 0;
201     if (is_leaf) {
202       pkey = ssl_cert_parse_pubkey(&certificate);
203       if (!pkey) {
204         ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
205         OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
206         return false;
207       }
208       // TLS 1.3 always uses certificate keys for signing thus the correct
209       // keyUsage is enforced.
210       if (!ssl_cert_check_key_usage(&certificate,
211                                     key_usage_digital_signature)) {
212         ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
213         return false;
214       }
215 
216       if (retain_sha256) {
217         // Retain the hash of the leaf certificate if requested.
218         SHA256(CBS_data(&certificate), CBS_len(&certificate),
219                hs->new_session->peer_sha256);
220       }
221     }
222 
223     UniquePtr<CRYPTO_BUFFER> buf(
224         CRYPTO_BUFFER_new_from_CBS(&certificate, ssl->ctx->pool));
225     if (!buf ||  //
226         !PushToStack(certs.get(), std::move(buf))) {
227       ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
228       return false;
229     }
230 
231     // Parse out the extensions.
232     SSLExtension status_request(
233         TLSEXT_TYPE_status_request,
234         !ssl->server && hs->config->ocsp_stapling_enabled);
235     SSLExtension sct(
236         TLSEXT_TYPE_certificate_timestamp,
237         !ssl->server && hs->config->signed_cert_timestamps_enabled);
238     SSLExtension trust_anchors(
239         TLSEXT_TYPE_trust_anchors,
240         !ssl->server && is_leaf &&
241             hs->config->requested_trust_anchors.has_value());
242     uint8_t alert = SSL_AD_DECODE_ERROR;
243     if (!ssl_parse_extensions(&extensions, &alert,
244                               {&status_request, &sct, &trust_anchors},
245                               /*ignore_unknown=*/false)) {
246       ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
247       return false;
248     }
249 
250     // All Certificate extensions are parsed, but only the leaf extensions are
251     // stored.
252     if (status_request.present) {
253       uint8_t status_type;
254       CBS ocsp_response;
255       if (!CBS_get_u8(&status_request.data, &status_type) ||
256           status_type != TLSEXT_STATUSTYPE_ocsp ||
257           !CBS_get_u24_length_prefixed(&status_request.data, &ocsp_response) ||
258           CBS_len(&ocsp_response) == 0 || CBS_len(&status_request.data) != 0) {
259         ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
260         return false;
261       }
262 
263       if (sk_CRYPTO_BUFFER_num(certs.get()) == 1) {
264         hs->new_session->ocsp_response.reset(
265             CRYPTO_BUFFER_new_from_CBS(&ocsp_response, ssl->ctx->pool));
266         if (hs->new_session->ocsp_response == nullptr) {
267           ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
268           return false;
269         }
270       }
271     }
272 
273     if (sct.present) {
274       if (!ssl_is_sct_list_valid(&sct.data)) {
275         OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_PARSING_EXTENSION);
276         ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
277         return false;
278       }
279 
280       if (sk_CRYPTO_BUFFER_num(certs.get()) == 1) {
281         hs->new_session->signed_cert_timestamp_list.reset(
282             CRYPTO_BUFFER_new_from_CBS(&sct.data, ssl->ctx->pool));
283         if (hs->new_session->signed_cert_timestamp_list == nullptr) {
284           ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
285           return false;
286         }
287       }
288     }
289 
290     if (trust_anchors.present) {
291       if (CBS_len(&trust_anchors.data) != 0) {
292         OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_PARSING_EXTENSION);
293         ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
294         return false;
295       }
296       hs->peer_matched_trust_anchor = true;
297     }
298   }
299 
300   // Store a null certificate list rather than an empty one if the peer didn't
301   // send certificates.
302   if (sk_CRYPTO_BUFFER_num(certs.get()) == 0) {
303     certs.reset();
304   }
305 
306   hs->peer_pubkey = std::move(pkey);
307   hs->new_session->certs = std::move(certs);
308 
309   if (!ssl->ctx->x509_method->session_cache_objects(hs->new_session.get())) {
310     OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
311     ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
312     return false;
313   }
314 
315   if (sk_CRYPTO_BUFFER_num(hs->new_session->certs.get()) == 0) {
316     if (!allow_anonymous) {
317       OPENSSL_PUT_ERROR(SSL, SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
318       ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_CERTIFICATE_REQUIRED);
319       return false;
320     }
321 
322     // OpenSSL returns X509_V_OK when no certificates are requested. This is
323     // classed by them as a bug, but it's assumed by at least NGINX.
324     hs->new_session->verify_result = X509_V_OK;
325 
326     // No certificate, so nothing more to do.
327     return true;
328   }
329 
330   hs->new_session->peer_sha256_valid = retain_sha256;
331   return true;
332 }
333 
tls13_process_certificate_verify(SSL_HANDSHAKE * hs,const SSLMessage & msg)334 bool tls13_process_certificate_verify(SSL_HANDSHAKE *hs,
335                                       const SSLMessage &msg) {
336   SSL *const ssl = hs->ssl;
337   if (hs->peer_pubkey == NULL) {
338     OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
339     return false;
340   }
341 
342   CBS body = msg.body, signature;
343   uint16_t signature_algorithm;
344   if (!CBS_get_u16(&body, &signature_algorithm) ||        //
345       !CBS_get_u16_length_prefixed(&body, &signature) ||  //
346       CBS_len(&body) != 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   uint8_t alert = SSL_AD_DECODE_ERROR;
353   if (!tls12_check_peer_sigalg(hs, &alert, signature_algorithm,
354                                hs->peer_pubkey.get())) {
355     ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
356     return false;
357   }
358   hs->new_session->peer_signature_algorithm = signature_algorithm;
359 
360   Array<uint8_t> input;
361   if (!tls13_get_cert_verify_signature_input(
362           hs, &input,
363           ssl->server ? ssl_cert_verify_client : ssl_cert_verify_server)) {
364     ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
365     return false;
366   }
367 
368   if (!ssl_public_key_verify(ssl, signature, signature_algorithm,
369                              hs->peer_pubkey.get(), input)) {
370     OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SIGNATURE);
371     ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
372     return false;
373   }
374 
375   return true;
376 }
377 
tls13_process_finished(SSL_HANDSHAKE * hs,const SSLMessage & msg,bool use_saved_value)378 bool tls13_process_finished(SSL_HANDSHAKE *hs, const SSLMessage &msg,
379                             bool use_saved_value) {
380   SSL *const ssl = hs->ssl;
381   uint8_t verify_data_buf[EVP_MAX_MD_SIZE];
382   Span<const uint8_t> verify_data;
383   if (use_saved_value) {
384     assert(ssl->server);
385     verify_data = hs->expected_client_finished;
386   } else {
387     size_t len;
388     if (!tls13_finished_mac(hs, verify_data_buf, &len, !ssl->server)) {
389       return false;
390     }
391     verify_data = Span(verify_data_buf, len);
392   }
393 
394   bool finished_ok =
395       CBS_mem_equal(&msg.body, verify_data.data(), verify_data.size());
396   if (CRYPTO_fuzzer_mode_enabled()) {
397     finished_ok = true;
398   }
399   if (!finished_ok) {
400     ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
401     OPENSSL_PUT_ERROR(SSL, SSL_R_DIGEST_CHECK_FAILED);
402     return false;
403   }
404 
405   return true;
406 }
407 
tls13_add_certificate(SSL_HANDSHAKE * hs)408 bool tls13_add_certificate(SSL_HANDSHAKE *hs) {
409   SSL *const ssl = hs->ssl;
410   const SSL_CREDENTIAL *cred = hs->credential.get();
411 
412   ScopedCBB cbb;
413   CBB *body, body_storage, certificate_list;
414 
415   if (hs->cert_compression_negotiated) {
416     if (!CBB_init(cbb.get(), 1024)) {
417       return false;
418     }
419     body = cbb.get();
420   } else {
421     body = &body_storage;
422     if (!ssl->method->init_message(ssl, cbb.get(), body, SSL3_MT_CERTIFICATE)) {
423       return false;
424     }
425   }
426 
427   if (  // The request context is always empty in the handshake.
428       !CBB_add_u8(body, 0) ||
429       !CBB_add_u24_length_prefixed(body, &certificate_list)) {
430     OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
431     return false;
432   }
433 
434   if (hs->credential == nullptr) {
435     return ssl_add_message_cbb(ssl, cbb.get());
436   }
437 
438   assert(hs->credential->UsesX509());
439   CRYPTO_BUFFER *leaf_buf = sk_CRYPTO_BUFFER_value(cred->chain.get(), 0);
440   CBB leaf, extensions;
441   if (!CBB_add_u24_length_prefixed(&certificate_list, &leaf) ||
442       !CBB_add_bytes(&leaf, CRYPTO_BUFFER_data(leaf_buf),
443                      CRYPTO_BUFFER_len(leaf_buf)) ||
444       !CBB_add_u16_length_prefixed(&certificate_list, &extensions)) {
445     OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
446     return false;
447   }
448 
449   if (hs->scts_requested && cred->signed_cert_timestamp_list != nullptr) {
450     CBB contents;
451     if (!CBB_add_u16(&extensions, TLSEXT_TYPE_certificate_timestamp) ||
452         !CBB_add_u16_length_prefixed(&extensions, &contents) ||
453         !CBB_add_bytes(
454             &contents,
455             CRYPTO_BUFFER_data(cred->signed_cert_timestamp_list.get()),
456             CRYPTO_BUFFER_len(cred->signed_cert_timestamp_list.get())) ||
457         !CBB_flush(&extensions)) {
458       OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
459       return false;
460     }
461   }
462 
463   if (hs->ocsp_stapling_requested && cred->ocsp_response != NULL) {
464     CBB contents, ocsp_response;
465     if (!CBB_add_u16(&extensions, TLSEXT_TYPE_status_request) ||
466         !CBB_add_u16_length_prefixed(&extensions, &contents) ||
467         !CBB_add_u8(&contents, TLSEXT_STATUSTYPE_ocsp) ||
468         !CBB_add_u24_length_prefixed(&contents, &ocsp_response) ||
469         !CBB_add_bytes(&ocsp_response,
470                        CRYPTO_BUFFER_data(cred->ocsp_response.get()),
471                        CRYPTO_BUFFER_len(cred->ocsp_response.get())) ||
472         !CBB_flush(&extensions)) {
473       OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
474       return false;
475     }
476   }
477 
478   if (cred->type == SSLCredentialType::kDelegated) {
479     CBB child;
480     if (!CBB_add_u16(&extensions, TLSEXT_TYPE_delegated_credential) ||
481         !CBB_add_u16_length_prefixed(&extensions, &child) ||
482         !CBB_add_bytes(&child, CRYPTO_BUFFER_data(cred->dc.get()),
483                        CRYPTO_BUFFER_len(cred->dc.get())) ||
484         !CBB_flush(&extensions)) {
485       OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
486       return false;
487     }
488   }
489 
490   if (hs->matched_peer_trust_anchor) {
491     // Let the peer know we matched a requested trust anchor.
492     CBB empty_contents;
493     if (!CBB_add_u16(&extensions, TLSEXT_TYPE_trust_anchors) ||        //
494         !CBB_add_u16_length_prefixed(&extensions, &empty_contents) ||  //
495         !CBB_flush(&extensions)) {
496       return false;
497     }
498   }
499 
500   for (size_t i = 1; i < sk_CRYPTO_BUFFER_num(cred->chain.get()); i++) {
501     CRYPTO_BUFFER *cert_buf = sk_CRYPTO_BUFFER_value(cred->chain.get(), i);
502     CBB child;
503     if (!CBB_add_u24_length_prefixed(&certificate_list, &child) ||
504         !CBB_add_bytes(&child, CRYPTO_BUFFER_data(cert_buf),
505                        CRYPTO_BUFFER_len(cert_buf)) ||
506         !CBB_add_u16(&certificate_list, 0 /* no extensions */)) {
507       OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
508       return false;
509     }
510   }
511 
512   if (!hs->cert_compression_negotiated) {
513     return ssl_add_message_cbb(ssl, cbb.get());
514   }
515 
516   Array<uint8_t> msg;
517   if (!CBBFinishArray(cbb.get(), &msg)) {
518     OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
519     return false;
520   }
521 
522   const CertCompressionAlg *alg = nullptr;
523   for (const auto &candidate : ssl->ctx->cert_compression_algs) {
524     if (candidate.alg_id == hs->cert_compression_alg_id) {
525       alg = &candidate;
526       break;
527     }
528   }
529 
530   if (alg == nullptr || alg->compress == nullptr) {
531     OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
532     return false;
533   }
534 
535   CBB compressed;
536   body = &body_storage;
537   if (!ssl->method->init_message(ssl, cbb.get(), body,
538                                  SSL3_MT_COMPRESSED_CERTIFICATE) ||
539       !CBB_add_u16(body, hs->cert_compression_alg_id) ||
540       msg.size() > (1u << 24) - 1 ||  //
541       !CBB_add_u24(body, static_cast<uint32_t>(msg.size())) ||
542       !CBB_add_u24_length_prefixed(body, &compressed)) {
543     OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
544     return false;
545   }
546 
547   SSL_HANDSHAKE_HINTS *const hints = hs->hints.get();
548   if (hints && !hs->hints_requested &&
549       hints->cert_compression_alg_id == hs->cert_compression_alg_id &&
550       hints->cert_compression_input == Span(msg) &&
551       !hints->cert_compression_output.empty()) {
552     if (!CBB_add_bytes(&compressed, hints->cert_compression_output.data(),
553                        hints->cert_compression_output.size())) {
554       OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
555       return false;
556     }
557   } else {
558     if (!alg->compress(ssl, &compressed, msg.data(), msg.size())) {
559       OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
560       return false;
561     }
562     if (hints && hs->hints_requested) {
563       hints->cert_compression_alg_id = hs->cert_compression_alg_id;
564       if (!hints->cert_compression_input.CopyFrom(msg) ||
565           !hints->cert_compression_output.CopyFrom(
566               Span(CBB_data(&compressed), CBB_len(&compressed)))) {
567         return false;
568       }
569     }
570   }
571 
572   if (!ssl_add_message_cbb(ssl, cbb.get())) {
573     OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
574     return false;
575   }
576 
577   return true;
578 }
579 
tls13_add_certificate_verify(SSL_HANDSHAKE * hs)580 enum ssl_private_key_result_t tls13_add_certificate_verify(SSL_HANDSHAKE *hs) {
581   SSL *const ssl = hs->ssl;
582   assert(hs->signature_algorithm != 0);
583   ScopedCBB cbb;
584   CBB body;
585   if (!ssl->method->init_message(ssl, cbb.get(), &body,
586                                  SSL3_MT_CERTIFICATE_VERIFY) ||
587       !CBB_add_u16(&body, hs->signature_algorithm)) {
588     OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
589     return ssl_private_key_failure;
590   }
591 
592   CBB child;
593   const size_t max_sig_len = EVP_PKEY_size(hs->credential->pubkey.get());
594   uint8_t *sig;
595   size_t sig_len;
596   if (!CBB_add_u16_length_prefixed(&body, &child) ||
597       !CBB_reserve(&child, &sig, max_sig_len)) {
598     ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
599     return ssl_private_key_failure;
600   }
601 
602   Array<uint8_t> msg;
603   if (!tls13_get_cert_verify_signature_input(
604           hs, &msg,
605           ssl->server ? ssl_cert_verify_server : ssl_cert_verify_client)) {
606     ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
607     return ssl_private_key_failure;
608   }
609 
610   enum ssl_private_key_result_t sign_result = ssl_private_key_sign(
611       hs, sig, &sig_len, max_sig_len, hs->signature_algorithm, msg);
612   if (sign_result != ssl_private_key_success) {
613     return sign_result;
614   }
615 
616   if (!CBB_did_write(&child, sig_len) ||  //
617       !ssl_add_message_cbb(ssl, cbb.get())) {
618     return ssl_private_key_failure;
619   }
620 
621   return ssl_private_key_success;
622 }
623 
tls13_add_finished(SSL_HANDSHAKE * hs)624 bool tls13_add_finished(SSL_HANDSHAKE *hs) {
625   SSL *const ssl = hs->ssl;
626   size_t verify_data_len;
627   uint8_t verify_data[EVP_MAX_MD_SIZE];
628 
629   if (!tls13_finished_mac(hs, verify_data, &verify_data_len, ssl->server)) {
630     ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
631     OPENSSL_PUT_ERROR(SSL, SSL_R_DIGEST_CHECK_FAILED);
632     return false;
633   }
634 
635   ScopedCBB cbb;
636   CBB body;
637   if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_FINISHED) ||
638       !CBB_add_bytes(&body, verify_data, verify_data_len) ||
639       !ssl_add_message_cbb(ssl, cbb.get())) {
640     return false;
641   }
642 
643   return true;
644 }
645 
tls13_add_key_update(SSL * ssl,int request_type)646 bool tls13_add_key_update(SSL *ssl, int request_type) {
647   if (ssl->s3->key_update_pending) {
648     return true;
649   }
650 
651   // We do not support multiple parallel outgoing flights. If there is an
652   // outgoing flight pending, queue the KeyUpdate for later.
653   if (SSL_is_dtls(ssl) && !ssl->d1->outgoing_messages.empty()) {
654     ssl->d1->queued_key_update = request_type == SSL_KEY_UPDATE_REQUESTED
655                                      ? QueuedKeyUpdate::kUpdateRequested
656                                      : QueuedKeyUpdate::kUpdateNotRequested;
657     return true;
658   }
659 
660   ScopedCBB cbb;
661   CBB body_cbb;
662   if (!ssl->method->init_message(ssl, cbb.get(), &body_cbb,
663                                  SSL3_MT_KEY_UPDATE) ||
664       !CBB_add_u8(&body_cbb, request_type) ||
665       !ssl_add_message_cbb(ssl, cbb.get())) {
666     return false;
667   }
668 
669   // In DTLS, the actual key update is deferred until KeyUpdate is ACKed.
670   if (!SSL_is_dtls(ssl) && !tls13_rotate_traffic_key(ssl, evp_aead_seal)) {
671     return false;
672   }
673 
674   // Suppress KeyUpdate acknowledgments until this change is written to the
675   // wire. This prevents us from accumulating write obligations when read and
676   // write progress at different rates. See RFC 8446, section 4.6.3.
677   ssl->s3->key_update_pending = true;
678   ssl->method->finish_flight(ssl);
679   return true;
680 }
681 
tls13_receive_key_update(SSL * ssl,const SSLMessage & msg)682 static bool tls13_receive_key_update(SSL *ssl, const SSLMessage &msg) {
683   CBS body = msg.body;
684   uint8_t key_update_request;
685   if (!CBS_get_u8(&body, &key_update_request) ||              //
686       CBS_len(&body) != 0 ||                                  //
687       (key_update_request != SSL_KEY_UPDATE_NOT_REQUESTED &&  //
688        key_update_request != SSL_KEY_UPDATE_REQUESTED)) {
689     OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
690     ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
691     return false;
692   }
693 
694   if (!tls13_rotate_traffic_key(ssl, evp_aead_open)) {
695     return false;
696   }
697 
698   // Acknowledge the KeyUpdate
699   if (key_update_request == SSL_KEY_UPDATE_REQUESTED &&
700       !tls13_add_key_update(ssl, SSL_KEY_UPDATE_NOT_REQUESTED)) {
701     return false;
702   }
703 
704   return true;
705 }
706 
tls13_post_handshake(SSL * ssl,const SSLMessage & msg)707 bool tls13_post_handshake(SSL *ssl, const SSLMessage &msg) {
708   if (msg.type == SSL3_MT_NEW_SESSION_TICKET && !ssl->server) {
709     return tls13_process_new_session_ticket(ssl, msg);
710   }
711 
712   if (msg.type == SSL3_MT_KEY_UPDATE) {
713     ssl->s3->key_update_count++;
714     if (SSL_is_quic(ssl) || ssl->s3->key_update_count > kMaxKeyUpdates) {
715       OPENSSL_PUT_ERROR(SSL, SSL_R_TOO_MANY_KEY_UPDATES);
716       ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
717       return false;
718     }
719 
720     return tls13_receive_key_update(ssl, msg);
721   }
722 
723   ssl->s3->key_update_count = 0;
724 
725   ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
726   OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);
727   return false;
728 }
729 
730 BSSL_NAMESPACE_END
731