xref: /openbsd/lib/libssl/tls13_internal.h (revision 8699d7a9)
1 /* $OpenBSD: tls13_internal.h,v 1.104 2024/09/09 03:32:29 tb Exp $ */
2 /*
3  * Copyright (c) 2018 Bob Beck <beck@openbsd.org>
4  * Copyright (c) 2018 Theo Buehler <tb@openbsd.org>
5  * Copyright (c) 2018, 2019 Joel Sing <jsing@openbsd.org>
6  *
7  * Permission to use, copy, modify, and/or distribute this software for any
8  * purpose with or without fee is hereby granted, provided that the above
9  * copyright notice and this permission notice appear in all copies.
10  *
11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
14  * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
16  * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
17  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18  */
19 
20 #ifndef HEADER_TLS13_INTERNAL_H
21 #define HEADER_TLS13_INTERNAL_H
22 
23 #include <openssl/evp.h>
24 #include <openssl/ssl.h>
25 
26 #include "bytestring.h"
27 #include "tls_internal.h"
28 
29 __BEGIN_HIDDEN_DECLS
30 
31 #define TLS13_HS_CLIENT			1
32 #define TLS13_HS_SERVER			2
33 
34 #define TLS13_IO_SUCCESS		 1
35 #define TLS13_IO_EOF			 0
36 #define TLS13_IO_FAILURE		-1
37 #define TLS13_IO_ALERT			-2
38 #define TLS13_IO_WANT_POLLIN		-3
39 #define TLS13_IO_WANT_POLLOUT		-4
40 #define TLS13_IO_WANT_RETRY		-5 /* Retry the previous call immediately. */
41 #define TLS13_IO_USE_LEGACY		-6
42 #define TLS13_IO_RECORD_VERSION		-7
43 #define TLS13_IO_RECORD_OVERFLOW	-8
44 
45 #define TLS13_ERR_VERIFY_FAILED		16
46 #define TLS13_ERR_HRR_FAILED		17
47 #define TLS13_ERR_TRAILING_DATA		18
48 #define TLS13_ERR_NO_SHARED_CIPHER	19
49 #define TLS13_ERR_NO_CERTIFICATE	20
50 #define TLS13_ERR_NO_PEER_CERTIFICATE	21
51 
52 #define TLS13_ALERT_LEVEL_WARNING			1
53 #define TLS13_ALERT_LEVEL_FATAL				2
54 
55 #define TLS13_ALERT_CLOSE_NOTIFY			0
56 #define TLS13_ALERT_UNEXPECTED_MESSAGE			10
57 #define TLS13_ALERT_BAD_RECORD_MAC			20
58 #define TLS13_ALERT_RECORD_OVERFLOW			22
59 #define TLS13_ALERT_HANDSHAKE_FAILURE			40
60 #define TLS13_ALERT_BAD_CERTIFICATE			42
61 #define TLS13_ALERT_UNSUPPORTED_CERTIFICATE		43
62 #define TLS13_ALERT_CERTIFICATE_REVOKED			44
63 #define TLS13_ALERT_CERTIFICATE_EXPIRED			45
64 #define TLS13_ALERT_CERTIFICATE_UNKNOWN			46
65 #define TLS13_ALERT_ILLEGAL_PARAMETER			47
66 #define TLS13_ALERT_UNKNOWN_CA				48
67 #define TLS13_ALERT_ACCESS_DENIED			49
68 #define TLS13_ALERT_DECODE_ERROR			50
69 #define TLS13_ALERT_DECRYPT_ERROR			51
70 #define TLS13_ALERT_PROTOCOL_VERSION			70
71 #define TLS13_ALERT_INSUFFICIENT_SECURITY		71
72 #define TLS13_ALERT_INTERNAL_ERROR			80
73 #define TLS13_ALERT_INAPPROPRIATE_FALLBACK		86
74 #define TLS13_ALERT_USER_CANCELED			90
75 #define TLS13_ALERT_MISSING_EXTENSION			109
76 #define TLS13_ALERT_UNSUPPORTED_EXTENSION		110
77 #define TLS13_ALERT_UNRECOGNIZED_NAME			112
78 #define TLS13_ALERT_BAD_CERTIFICATE_STATUS_RESPONSE	113
79 #define TLS13_ALERT_UNKNOWN_PSK_IDENTITY		115
80 #define TLS13_ALERT_CERTIFICATE_REQUIRED		116
81 #define TLS13_ALERT_NO_APPLICATION_PROTOCOL		120
82 
83 #define TLS13_INFO_HANDSHAKE_STARTED			SSL_CB_HANDSHAKE_START
84 #define TLS13_INFO_HANDSHAKE_COMPLETED			SSL_CB_HANDSHAKE_DONE
85 #define TLS13_INFO_ACCEPT_LOOP				SSL_CB_ACCEPT_LOOP
86 #define TLS13_INFO_CONNECT_LOOP				SSL_CB_CONNECT_LOOP
87 #define TLS13_INFO_ACCEPT_EXIT				SSL_CB_ACCEPT_EXIT
88 #define TLS13_INFO_CONNECT_EXIT				SSL_CB_CONNECT_EXIT
89 
90 typedef void (*tls13_alert_cb)(uint8_t _alert_level, uint8_t _alert_desc,
91     void *_cb_arg);
92 typedef ssize_t (*tls13_phh_recv_cb)(void *_cb_arg);
93 typedef void (*tls13_phh_sent_cb)(void *_cb_arg);
94 typedef void (*tls13_handshake_message_cb)(void *_cb_arg);
95 typedef void (*tls13_info_cb)(void *_cb_arg, int _state, int _ret);
96 typedef int (*tls13_ocsp_status_cb)(void *_cb_arg);
97 
98 /*
99  * PSK support.
100  */
101 
102 /*
103  * Known PskKeyExchangeMode values.
104  * https://www.iana.org/assignments/tls-parameters/#tls-pskkeyexchangemode
105  */
106 #define TLS13_PSK_KE					0
107 #define TLS13_PSK_DHE_KE				1
108 
109 /*
110  * Secrets.
111  */
112 struct tls13_secret {
113 	uint8_t *data;
114 	size_t len;
115 };
116 
117 /* RFC 8446 Section 7.1  Page 92 */
118 struct tls13_secrets {
119 	const EVP_MD *digest;
120 	int resumption;
121 	int init_done;
122 	int early_done;
123 	int handshake_done;
124 	int schedule_done;
125 	int insecure; /* Set by tests */
126 	struct tls13_secret zeros;
127 	struct tls13_secret empty_hash;
128 	struct tls13_secret extracted_early;
129 	struct tls13_secret binder_key;
130 	struct tls13_secret client_early_traffic;
131 	struct tls13_secret early_exporter_master;
132 	struct tls13_secret derived_early;
133 	struct tls13_secret extracted_handshake;
134 	struct tls13_secret client_handshake_traffic;
135 	struct tls13_secret server_handshake_traffic;
136 	struct tls13_secret derived_handshake;
137 	struct tls13_secret extracted_master;
138 	struct tls13_secret client_application_traffic;
139 	struct tls13_secret server_application_traffic;
140 	struct tls13_secret exporter_master;
141 	struct tls13_secret resumption_master;
142 };
143 
144 int tls13_secret_init(struct tls13_secret *secret, size_t len);
145 void tls13_secret_cleanup(struct tls13_secret *secret);
146 struct tls13_secrets *tls13_secrets_create(const EVP_MD *digest,
147     int resumption);
148 void tls13_secrets_destroy(struct tls13_secrets *secrets);
149 
150 int tls13_hkdf_expand_label(struct tls13_secret *out, const EVP_MD *digest,
151     const struct tls13_secret *secret, const char *label,
152     const struct tls13_secret *context);
153 int tls13_hkdf_expand_label_with_length(struct tls13_secret *out,
154     const EVP_MD *digest, const struct tls13_secret *secret,
155     const uint8_t *label, size_t label_len, const struct tls13_secret *context);
156 
157 int tls13_derive_secret(struct tls13_secret *out, const EVP_MD *digest,
158     const struct tls13_secret *secret, const char *label,
159     const struct tls13_secret *context);
160 int tls13_derive_secret_with_label_length(struct tls13_secret *out,
161     const EVP_MD *digest, const struct tls13_secret *secret,
162     const uint8_t *label, size_t label_len, const struct tls13_secret *context);
163 
164 int tls13_derive_early_secrets(struct tls13_secrets *secrets, uint8_t *psk,
165     size_t psk_len, const struct tls13_secret *context);
166 int tls13_derive_handshake_secrets(struct tls13_secrets *secrets,
167     const uint8_t *ecdhe, size_t ecdhe_len, const struct tls13_secret *context);
168 int tls13_derive_application_secrets(struct tls13_secrets *secrets,
169     const struct tls13_secret *context);
170 int tls13_update_client_traffic_secret(struct tls13_secrets *secrets);
171 int tls13_update_server_traffic_secret(struct tls13_secrets *secrets);
172 
173 /*
174  * Record Layer.
175  */
176 struct tls13_record_layer;
177 
178 struct tls13_record_layer_callbacks {
179 	/* Wire callbacks. */
180 	tls_read_cb wire_read;
181 	tls_write_cb wire_write;
182 	tls_flush_cb wire_flush;
183 
184 	/* Interceptors. */
185 	tls_handshake_read_cb handshake_read;
186 	tls_handshake_write_cb handshake_write;
187 	tls_traffic_key_cb set_read_traffic_key;
188 	tls_traffic_key_cb set_write_traffic_key;
189 	tls_alert_send_cb alert_send;
190 
191 	/* Notification callbacks. */
192 	tls13_alert_cb alert_recv;
193 	tls13_alert_cb alert_sent;
194 	tls13_phh_recv_cb phh_recv;
195 	tls13_phh_sent_cb phh_sent;
196 };
197 
198 struct tls13_record_layer *tls13_record_layer_new(
199     const struct tls13_record_layer_callbacks *callbacks, void *cb_arg);
200 void tls13_record_layer_free(struct tls13_record_layer *rl);
201 void tls13_record_layer_set_callbacks(struct tls13_record_layer *rl,
202     const struct tls13_record_layer_callbacks *callbacks, void *cb_arg);
203 void tls13_record_layer_allow_ccs(struct tls13_record_layer *rl, int allow);
204 void tls13_record_layer_allow_legacy_alerts(struct tls13_record_layer *rl, int allow);
205 void tls13_record_layer_rcontent(struct tls13_record_layer *rl, CBS *cbs);
206 void tls13_record_layer_set_aead(struct tls13_record_layer *rl,
207     const EVP_AEAD *aead);
208 void tls13_record_layer_set_hash(struct tls13_record_layer *rl,
209     const EVP_MD *hash);
210 void tls13_record_layer_set_legacy_version(struct tls13_record_layer *rl,
211     uint16_t version);
212 void tls13_record_layer_set_retry_after_phh(struct tls13_record_layer *rl, int retry);
213 void tls13_record_layer_alert_sent(struct tls13_record_layer *rl,
214     uint8_t alert_level, uint8_t alert_desc);
215 void tls13_record_layer_handshake_completed(struct tls13_record_layer *rl);
216 int tls13_record_layer_set_read_traffic_key(struct tls13_record_layer *rl,
217     struct tls13_secret *read_key, enum ssl_encryption_level_t read_level);
218 int tls13_record_layer_set_write_traffic_key(struct tls13_record_layer *rl,
219     struct tls13_secret *write_key, enum ssl_encryption_level_t write_level);
220 ssize_t tls13_record_layer_send_pending(struct tls13_record_layer *rl);
221 ssize_t tls13_record_layer_phh(struct tls13_record_layer *rl, CBS *cbs);
222 ssize_t tls13_record_layer_flush(struct tls13_record_layer *rl);
223 
224 ssize_t tls13_read_handshake_data(struct tls13_record_layer *rl, uint8_t *buf, size_t n);
225 ssize_t tls13_write_handshake_data(struct tls13_record_layer *rl, const uint8_t *buf,
226     size_t n);
227 ssize_t tls13_pending_application_data(struct tls13_record_layer *rl);
228 ssize_t tls13_peek_application_data(struct tls13_record_layer *rl, uint8_t *buf, size_t n);
229 ssize_t tls13_read_application_data(struct tls13_record_layer *rl, uint8_t *buf, size_t n);
230 ssize_t tls13_write_application_data(struct tls13_record_layer *rl, const uint8_t *buf,
231     size_t n);
232 
233 ssize_t tls13_send_alert(struct tls13_record_layer *rl, uint8_t alert_desc);
234 ssize_t tls13_send_dummy_ccs(struct tls13_record_layer *rl);
235 
236 /*
237  * Handshake Messages.
238  */
239 struct tls13_handshake_msg;
240 
241 struct tls13_handshake_msg *tls13_handshake_msg_new(void);
242 void tls13_handshake_msg_free(struct tls13_handshake_msg *msg);
243 void tls13_handshake_msg_data(struct tls13_handshake_msg *msg, CBS *cbs);
244 uint8_t tls13_handshake_msg_type(struct tls13_handshake_msg *msg);
245 int tls13_handshake_msg_content(struct tls13_handshake_msg *msg, CBS *cbs);
246 int tls13_handshake_msg_start(struct tls13_handshake_msg *msg, CBB *body,
247     uint8_t msg_type);
248 int tls13_handshake_msg_finish(struct tls13_handshake_msg *msg);
249 int tls13_handshake_msg_recv(struct tls13_handshake_msg *msg,
250     struct tls13_record_layer *rl);
251 int tls13_handshake_msg_send(struct tls13_handshake_msg *msg,
252     struct tls13_record_layer *rl);
253 
254 struct tls13_handshake_stage {
255 	uint8_t	hs_type;
256 	uint8_t	message_number;
257 };
258 
259 struct ssl_handshake_tls13_st;
260 
261 struct tls13_error {
262 	int code;
263 	int subcode;
264 	int errnum;
265 	const char *file;
266 	int line;
267 	char *msg;
268 };
269 
270 struct tls13_ctx {
271 	struct tls13_error error;
272 
273 	SSL *ssl;
274 	struct ssl_handshake_st *hs;
275 	uint8_t	mode;
276 	struct tls13_handshake_stage handshake_stage;
277 	int handshake_started;
278 	int handshake_completed;
279 	int need_flush;
280 	int middlebox_compat;
281 	int send_dummy_ccs;
282 	int send_dummy_ccs_after;
283 
284 	int close_notify_sent;
285 	int close_notify_recv;
286 
287 	const EVP_AEAD *aead;
288 	const EVP_MD *hash;
289 
290 	struct tls13_record_layer *rl;
291 	struct tls13_handshake_msg *hs_msg;
292 	uint8_t key_update_request;
293 	uint8_t alert;
294 	int phh_count;
295 	time_t phh_last_seen;
296 
297 	tls13_alert_cb alert_sent_cb;
298 	tls13_alert_cb alert_recv_cb;
299 	tls13_handshake_message_cb handshake_message_sent_cb;
300 	tls13_handshake_message_cb handshake_message_recv_cb;
301 	tls13_info_cb info_cb;
302 	tls13_ocsp_status_cb ocsp_status_recv_cb;
303 };
304 #ifndef TLS13_PHH_LIMIT_TIME
305 #define TLS13_PHH_LIMIT_TIME 3600
306 #endif
307 #ifndef TLS13_PHH_LIMIT
308 #define TLS13_PHH_LIMIT 100
309 #endif
310 
311 struct tls13_ctx *tls13_ctx_new(int mode, SSL *ssl);
312 void tls13_ctx_free(struct tls13_ctx *ctx);
313 
314 const EVP_AEAD *tls13_cipher_aead(const SSL_CIPHER *cipher);
315 const EVP_MD *tls13_cipher_hash(const SSL_CIPHER *cipher);
316 
317 void tls13_alert_received_cb(uint8_t alert_level, uint8_t alert_desc, void *arg);
318 void tls13_alert_sent_cb(uint8_t alert_level, uint8_t alert_desc, void *arg);
319 ssize_t tls13_phh_received_cb(void *cb_arg);
320 void tls13_phh_done_cb(void *cb_arg);
321 
322 int tls13_quic_init(struct tls13_ctx *ctx);
323 
324 /*
325  * Legacy interfaces.
326  */
327 int tls13_use_legacy_client(struct tls13_ctx *ctx);
328 int tls13_use_legacy_server(struct tls13_ctx *ctx);
329 int tls13_legacy_accept(SSL *ssl);
330 int tls13_legacy_connect(SSL *ssl);
331 ssize_t tls13_legacy_wire_read_cb(void *buf, size_t n, void *arg);
332 ssize_t tls13_legacy_wire_write_cb(const void *buf, size_t n, void *arg);
333 ssize_t tls13_legacy_wire_flush_cb(void *arg);
334 int tls13_legacy_pending(const SSL *ssl);
335 int tls13_legacy_read_bytes(SSL *ssl, int type, unsigned char *buf, int len,
336     int peek);
337 int tls13_legacy_write_bytes(SSL *ssl, int type, const void *buf, int len);
338 int tls13_legacy_shutdown(SSL *ssl);
339 int tls13_legacy_servername_process(struct tls13_ctx *ctx, uint8_t *alert);
340 
341 /*
342  * Message Types - RFC 8446, Section B.3.
343  *
344  * Values listed as "_RESERVED" were used in previous versions of TLS and are
345  * listed here for completeness.  TLS 1.3 implementations MUST NOT send them but
346  * might receive them from older TLS implementations.
347  */
348 #define	TLS13_MT_HELLO_REQUEST_RESERVED		0
349 #define	TLS13_MT_CLIENT_HELLO			1
350 #define	TLS13_MT_SERVER_HELLO			2
351 #define	TLS13_MT_HELLO_VERIFY_REQUEST_RESERVED	3
352 #define	TLS13_MT_NEW_SESSION_TICKET		4
353 #define	TLS13_MT_END_OF_EARLY_DATA		5
354 #define	TLS13_MT_HELLO_RETRY_REQUEST_RESERVED	6
355 #define	TLS13_MT_ENCRYPTED_EXTENSIONS		8
356 #define	TLS13_MT_CERTIFICATE			11
357 #define	TLS13_MT_SERVER_KEY_EXCHANGE_RESERVED	12
358 #define	TLS13_MT_CERTIFICATE_REQUEST		13
359 #define	TLS13_MT_SERVER_HELLO_DONE_RESERVED	14
360 #define	TLS13_MT_CERTIFICATE_VERIFY		15
361 #define	TLS13_MT_CLIENT_KEY_EXCHANGE_RESERVED	16
362 #define	TLS13_MT_FINISHED			20
363 #define	TLS13_MT_CERTIFICATE_URL_RESERVED	21
364 #define	TLS13_MT_CERTIFICATE_STATUS_RESERVED	22
365 #define	TLS13_MT_SUPPLEMENTAL_DATA_RESERVED	23
366 #define	TLS13_MT_KEY_UPDATE			24
367 #define	TLS13_MT_MESSAGE_HASH			254
368 
369 int tls13_handshake_msg_record(struct tls13_ctx *ctx);
370 int tls13_handshake_perform(struct tls13_ctx *ctx);
371 
372 int tls13_client_init(struct tls13_ctx *ctx);
373 int tls13_server_init(struct tls13_ctx *ctx);
374 int tls13_client_connect(struct tls13_ctx *ctx);
375 int tls13_server_accept(struct tls13_ctx *ctx);
376 
377 int tls13_client_hello_send(struct tls13_ctx *ctx, CBB *cbb);
378 int tls13_client_hello_sent(struct tls13_ctx *ctx);
379 int tls13_client_hello_recv(struct tls13_ctx *ctx, CBS *cbs);
380 int tls13_client_hello_retry_send(struct tls13_ctx *ctx, CBB *cbb);
381 int tls13_client_hello_retry_recv(struct tls13_ctx *ctx, CBS *cbs);
382 int tls13_client_end_of_early_data_send(struct tls13_ctx *ctx, CBB *cbb);
383 int tls13_client_end_of_early_data_recv(struct tls13_ctx *ctx, CBS *cbs);
384 int tls13_client_certificate_send(struct tls13_ctx *ctx, CBB *cbb);
385 int tls13_client_certificate_recv(struct tls13_ctx *ctx, CBS *cbs);
386 int tls13_client_certificate_verify_send(struct tls13_ctx *ctx, CBB *cbb);
387 int tls13_client_certificate_verify_recv(struct tls13_ctx *ctx, CBS *cbs);
388 int tls13_client_finished_recv(struct tls13_ctx *ctx, CBS *cbs);
389 int tls13_client_finished_send(struct tls13_ctx *ctx, CBB *cbb);
390 int tls13_client_finished_sent(struct tls13_ctx *ctx);
391 int tls13_server_hello_recv(struct tls13_ctx *ctx, CBS *cbs);
392 int tls13_server_hello_send(struct tls13_ctx *ctx, CBB *cbb);
393 int tls13_server_hello_sent(struct tls13_ctx *ctx);
394 int tls13_server_hello_retry_request_recv(struct tls13_ctx *ctx, CBS *cbs);
395 int tls13_server_hello_retry_request_send(struct tls13_ctx *ctx, CBB *cbb);
396 int tls13_server_hello_retry_request_sent(struct tls13_ctx *ctx);
397 int tls13_server_encrypted_extensions_recv(struct tls13_ctx *ctx, CBS *cbs);
398 int tls13_server_encrypted_extensions_send(struct tls13_ctx *ctx, CBB *cbb);
399 int tls13_server_certificate_recv(struct tls13_ctx *ctx, CBS *cbs);
400 int tls13_server_certificate_send(struct tls13_ctx *ctx, CBB *cbb);
401 int tls13_server_certificate_request_recv(struct tls13_ctx *ctx, CBS *cbs);
402 int tls13_server_certificate_request_send(struct tls13_ctx *ctx, CBB *cbb);
403 int tls13_server_certificate_verify_send(struct tls13_ctx *ctx, CBB *cbb);
404 int tls13_server_certificate_verify_recv(struct tls13_ctx *ctx, CBS *cbs);
405 int tls13_server_finished_recv(struct tls13_ctx *ctx, CBS *cbs);
406 int tls13_server_finished_send(struct tls13_ctx *ctx, CBB *cbb);
407 int tls13_server_finished_sent(struct tls13_ctx *ctx);
408 
409 void tls13_error_clear(struct tls13_error *error);
410 int tls13_cert_add(struct tls13_ctx *ctx, CBB *cbb, X509 *cert,
411     int(*build_extensions)(SSL *s, uint16_t msg_type, CBB *cbb));
412 
413 int tls13_synthetic_handshake_message(struct tls13_ctx *ctx);
414 int tls13_clienthello_hash_init(struct tls13_ctx *ctx);
415 void tls13_clienthello_hash_clear(struct ssl_handshake_tls13_st *hs);
416 int tls13_clienthello_hash_update_bytes(struct tls13_ctx *ctx, void *data,
417     size_t len);
418 int tls13_clienthello_hash_update(struct tls13_ctx *ctx, CBS *cbs);
419 int tls13_clienthello_hash_finalize(struct tls13_ctx *ctx);
420 int tls13_clienthello_hash_validate(struct tls13_ctx *ctx);
421 
422 int tls13_error_set(struct tls13_error *error, int code, int subcode,
423     const char *file, int line, const char *fmt, ...);
424 int tls13_error_setx(struct tls13_error *error, int code, int subcode,
425     const char *file, int line, const char *fmt, ...);
426 
427 #define tls13_set_error(ctx, code, subcode, fmt, ...) \
428 	tls13_error_set(&(ctx)->error, (code), (subcode), __FILE__, __LINE__, \
429 	    (fmt), __VA_ARGS__)
430 #define tls13_set_errorx(ctx, code, subcode, fmt, ...) \
431 	tls13_error_setx(&(ctx)->error, (code), (subcode), __FILE__, __LINE__, \
432 	    (fmt), __VA_ARGS__)
433 
434 int tls13_exporter(struct tls13_ctx *ctx, const uint8_t *label, size_t label_len,
435     const uint8_t *context_value, size_t context_value_len, uint8_t *out,
436     size_t out_len);
437 
438 extern const uint8_t tls13_downgrade_12[8];
439 extern const uint8_t tls13_downgrade_11[8];
440 extern const uint8_t tls13_hello_retry_request_hash[32];
441 extern const uint8_t tls13_cert_verify_pad[64];
442 extern const uint8_t tls13_cert_client_verify_context[];
443 extern const uint8_t tls13_cert_server_verify_context[];
444 
445 __END_HIDDEN_DECLS
446 
447 #endif
448