2 * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
12 #include "internal/cryptlib.h"
13 #include <openssl/evp.h>
14 #include <openssl/kdf.h>
16 #define TLS13_MAX_LABEL_LEN 246
18 /* Always filled with zeros */
19 static const unsigned char default_zeros[EVP_MAX_MD_SIZE];
22 * Given a |secret|; a |label| of length |labellen|; and |data| of length
23 * |datalen| (e.g. typically a hash of the handshake messages), derive a new
24 * secret |outlen| bytes long and store it in the location pointed to be |out|.
25 * The |data| value may be zero length. Returns 1 on success 0 on failure.
27 int tls13_hkdf_expand(SSL *s, const EVP_MD *md, const unsigned char *secret,
28 const unsigned char *label, size_t labellen,
29 const unsigned char *data, size_t datalen,
30 unsigned char *out, size_t outlen)
32 const unsigned char label_prefix[] = "tls13 ";
33 EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
38 * 2 bytes for length of whole HkdfLabel + 1 byte for length of combined
39 * prefix and label + bytes for the label itself + bytes for the hash
41 unsigned char hkdflabel[sizeof(uint16_t) + sizeof(uint8_t) +
42 + sizeof(label_prefix) + TLS13_MAX_LABEL_LEN
49 hashlen = EVP_MD_size(md);
51 if (!WPACKET_init_static_len(&pkt, hkdflabel, sizeof(hkdflabel), 0)
52 || !WPACKET_put_bytes_u16(&pkt, outlen)
53 || !WPACKET_start_sub_packet_u8(&pkt)
54 || !WPACKET_memcpy(&pkt, label_prefix, sizeof(label_prefix) - 1)
55 || !WPACKET_memcpy(&pkt, label, labellen)
56 || !WPACKET_close(&pkt)
57 || !WPACKET_sub_memcpy_u8(&pkt, data, (data == NULL) ? 0 : datalen)
58 || !WPACKET_get_total_written(&pkt, &hkdflabellen)
59 || !WPACKET_finish(&pkt)) {
60 EVP_PKEY_CTX_free(pctx);
61 WPACKET_cleanup(&pkt);
62 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
63 ERR_R_INTERNAL_ERROR);
67 ret = EVP_PKEY_derive_init(pctx) <= 0
68 || EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXPAND_ONLY)
70 || EVP_PKEY_CTX_set_hkdf_md(pctx, md) <= 0
71 || EVP_PKEY_CTX_set1_hkdf_key(pctx, secret, hashlen) <= 0
72 || EVP_PKEY_CTX_add1_hkdf_info(pctx, hkdflabel, hkdflabellen) <= 0
73 || EVP_PKEY_derive(pctx, out, &outlen) <= 0;
75 EVP_PKEY_CTX_free(pctx);
78 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
79 ERR_R_INTERNAL_ERROR);
85 * Given a |secret| generate a |key| of length |keylen| bytes. Returns 1 on
86 * success 0 on failure.
88 int tls13_derive_key(SSL *s, const EVP_MD *md, const unsigned char *secret,
89 unsigned char *key, size_t keylen)
91 static const unsigned char keylabel[] = "key";
93 return tls13_hkdf_expand(s, md, secret, keylabel, sizeof(keylabel) - 1,
94 NULL, 0, key, keylen);
98 * Given a |secret| generate an |iv| of length |ivlen| bytes. Returns 1 on
99 * success 0 on failure.
101 int tls13_derive_iv(SSL *s, const EVP_MD *md, const unsigned char *secret,
102 unsigned char *iv, size_t ivlen)
104 static const unsigned char ivlabel[] = "iv";
106 return tls13_hkdf_expand(s, md, secret, ivlabel, sizeof(ivlabel) - 1,
110 int tls13_derive_finishedkey(SSL *s, const EVP_MD *md,
111 const unsigned char *secret,
112 unsigned char *fin, size_t finlen)
114 static const unsigned char finishedlabel[] = "finished";
116 return tls13_hkdf_expand(s, md, secret, finishedlabel,
117 sizeof(finishedlabel) - 1, NULL, 0, fin, finlen);
121 * Given the previous secret |prevsecret| and a new input secret |insecret| of
122 * length |insecretlen|, generate a new secret and store it in the location
123 * pointed to by |outsecret|. Returns 1 on success 0 on failure.
125 int tls13_generate_secret(SSL *s, const EVP_MD *md,
126 const unsigned char *prevsecret,
127 const unsigned char *insecret,
129 unsigned char *outsecret)
131 size_t mdlen, prevsecretlen;
133 EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
134 static const char derived_secret_label[] = "derived";
135 unsigned char preextractsec[EVP_MAX_MD_SIZE];
138 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
139 ERR_R_INTERNAL_ERROR);
143 mdlen = EVP_MD_size(md);
145 if (insecret == NULL) {
146 insecret = default_zeros;
149 if (prevsecret == NULL) {
150 prevsecret = default_zeros;
153 EVP_MD_CTX *mctx = EVP_MD_CTX_new();
154 unsigned char hash[EVP_MAX_MD_SIZE];
156 /* The pre-extract derive step uses a hash of no messages */
158 || EVP_DigestInit_ex(mctx, md, NULL) <= 0
159 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
160 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
161 ERR_R_INTERNAL_ERROR);
162 EVP_MD_CTX_free(mctx);
163 EVP_PKEY_CTX_free(pctx);
166 EVP_MD_CTX_free(mctx);
168 /* Generate the pre-extract secret */
169 if (!tls13_hkdf_expand(s, md, prevsecret,
170 (unsigned char *)derived_secret_label,
171 sizeof(derived_secret_label) - 1, hash, mdlen,
172 preextractsec, mdlen)) {
173 /* SSLfatal() already called */
174 EVP_PKEY_CTX_free(pctx);
178 prevsecret = preextractsec;
179 prevsecretlen = mdlen;
182 ret = EVP_PKEY_derive_init(pctx) <= 0
183 || EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY)
185 || EVP_PKEY_CTX_set_hkdf_md(pctx, md) <= 0
186 || EVP_PKEY_CTX_set1_hkdf_key(pctx, insecret, insecretlen) <= 0
187 || EVP_PKEY_CTX_set1_hkdf_salt(pctx, prevsecret, prevsecretlen)
189 || EVP_PKEY_derive(pctx, outsecret, &mdlen)
193 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
194 ERR_R_INTERNAL_ERROR);
196 EVP_PKEY_CTX_free(pctx);
197 if (prevsecret == preextractsec)
198 OPENSSL_cleanse(preextractsec, mdlen);
203 * Given an input secret |insecret| of length |insecretlen| generate the
204 * handshake secret. This requires the early secret to already have been
205 * generated. Returns 1 on success 0 on failure.
207 int tls13_generate_handshake_secret(SSL *s, const unsigned char *insecret,
210 /* Calls SSLfatal() if required */
211 return tls13_generate_secret(s, ssl_handshake_md(s), s->early_secret,
212 insecret, insecretlen,
213 (unsigned char *)&s->handshake_secret);
217 * Given the handshake secret |prev| of length |prevlen| generate the master
218 * secret and store its length in |*secret_size|. Returns 1 on success 0 on
221 int tls13_generate_master_secret(SSL *s, unsigned char *out,
222 unsigned char *prev, size_t prevlen,
225 const EVP_MD *md = ssl_handshake_md(s);
227 *secret_size = EVP_MD_size(md);
228 /* Calls SSLfatal() if required */
229 return tls13_generate_secret(s, md, prev, NULL, 0, out);
233 * Generates the mac for the Finished message. Returns the length of the MAC or
236 size_t tls13_final_finish_mac(SSL *s, const char *str, size_t slen,
239 const EVP_MD *md = ssl_handshake_md(s);
240 unsigned char hash[EVP_MAX_MD_SIZE];
241 size_t hashlen, ret = 0;
242 EVP_PKEY *key = NULL;
243 EVP_MD_CTX *ctx = EVP_MD_CTX_new();
245 if (!ssl_handshake_hash(s, hash, sizeof(hash), &hashlen)) {
246 /* SSLfatal() already called */
250 if (str == s->method->ssl3_enc->server_finished_label)
251 key = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL,
252 s->server_finished_secret, hashlen);
254 key = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL,
255 s->client_finished_secret, hashlen);
259 || EVP_DigestSignInit(ctx, NULL, md, NULL, key) <= 0
260 || EVP_DigestSignUpdate(ctx, hash, hashlen) <= 0
261 || EVP_DigestSignFinal(ctx, out, &hashlen) <= 0) {
262 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_FINAL_FINISH_MAC,
263 ERR_R_INTERNAL_ERROR);
270 EVP_MD_CTX_free(ctx);
275 * There isn't really a key block in TLSv1.3, but we still need this function
276 * for initialising the cipher and hash. Returns 1 on success or 0 on failure.
278 int tls13_setup_key_block(SSL *s)
282 int mac_type = NID_undef;
284 s->session->cipher = s->s3->tmp.new_cipher;
285 if (!ssl_cipher_get_evp
286 (s->session, &c, &hash, &mac_type, NULL, NULL, 0)) {
287 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_SETUP_KEY_BLOCK,
288 SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
292 s->s3->tmp.new_sym_enc = c;
293 s->s3->tmp.new_hash = hash;
298 static int derive_secret_key_and_iv(SSL *s, int sending, const EVP_MD *md,
299 const EVP_CIPHER *ciph,
300 const unsigned char *insecret,
301 const unsigned char *hash,
302 const unsigned char *label,
303 size_t labellen, unsigned char *secret,
304 unsigned char *iv, EVP_CIPHER_CTX *ciph_ctx)
306 unsigned char key[EVP_MAX_KEY_LENGTH];
307 size_t ivlen, keylen, taglen;
308 size_t hashlen = EVP_MD_size(md);
310 if (!tls13_hkdf_expand(s, md, insecret, label, labellen, hash, hashlen,
312 /* SSLfatal() already called */
316 /* TODO(size_t): convert me */
317 keylen = EVP_CIPHER_key_length(ciph);
318 if (EVP_CIPHER_mode(ciph) == EVP_CIPH_CCM_MODE) {
321 ivlen = EVP_CCM_TLS_IV_LEN;
322 if (s->s3->tmp.new_cipher == NULL) {
323 /* We've not selected a cipher yet - we must be doing early data */
324 algenc = s->session->cipher->algorithm_enc;
326 algenc = s->s3->tmp.new_cipher->algorithm_enc;
328 if (algenc & (SSL_AES128CCM8 | SSL_AES256CCM8))
329 taglen = EVP_CCM8_TLS_TAG_LEN;
331 taglen = EVP_CCM_TLS_TAG_LEN;
333 ivlen = EVP_CIPHER_iv_length(ciph);
337 if (!tls13_derive_key(s, md, secret, key, keylen)
338 || !tls13_derive_iv(s, md, secret, iv, ivlen)) {
339 /* SSLfatal() already called */
343 if (EVP_CipherInit_ex(ciph_ctx, ciph, NULL, NULL, NULL, sending) <= 0
344 || !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
345 || (taglen != 0 && !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_TAG,
347 || EVP_CipherInit_ex(ciph_ctx, NULL, NULL, key, NULL, -1) <= 0) {
348 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DERIVE_SECRET_KEY_AND_IV,
355 OPENSSL_cleanse(key, sizeof(key));
359 int tls13_change_cipher_state(SSL *s, int which)
361 static const unsigned char client_early_traffic[] = "c e traffic";
362 static const unsigned char client_handshake_traffic[] = "c hs traffic";
363 static const unsigned char client_application_traffic[] = "c ap traffic";
364 static const unsigned char server_handshake_traffic[] = "s hs traffic";
365 static const unsigned char server_application_traffic[] = "s ap traffic";
366 static const unsigned char exporter_master_secret[] = "exp master";
367 static const unsigned char resumption_master_secret[] = "res master";
369 unsigned char secret[EVP_MAX_MD_SIZE];
370 unsigned char hashval[EVP_MAX_MD_SIZE];
371 unsigned char *hash = hashval;
372 unsigned char *insecret;
373 unsigned char *finsecret = NULL;
374 const char *log_label = NULL;
375 EVP_CIPHER_CTX *ciph_ctx;
376 size_t finsecretlen = 0;
377 const unsigned char *label;
378 size_t labellen, hashlen = 0;
380 const EVP_MD *md = NULL;
381 const EVP_CIPHER *cipher = NULL;
383 if (which & SSL3_CC_READ) {
384 if (s->enc_read_ctx != NULL) {
385 EVP_CIPHER_CTX_reset(s->enc_read_ctx);
387 s->enc_read_ctx = EVP_CIPHER_CTX_new();
388 if (s->enc_read_ctx == NULL) {
389 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
390 SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
394 ciph_ctx = s->enc_read_ctx;
397 RECORD_LAYER_reset_read_sequence(&s->rlayer);
399 if (s->enc_write_ctx != NULL) {
400 EVP_CIPHER_CTX_reset(s->enc_write_ctx);
402 s->enc_write_ctx = EVP_CIPHER_CTX_new();
403 if (s->enc_write_ctx == NULL) {
404 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
405 SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
409 ciph_ctx = s->enc_write_ctx;
412 RECORD_LAYER_reset_write_sequence(&s->rlayer);
415 if (((which & SSL3_CC_CLIENT) && (which & SSL3_CC_WRITE))
416 || ((which & SSL3_CC_SERVER) && (which & SSL3_CC_READ))) {
417 if (which & SSL3_CC_EARLY) {
418 EVP_MD_CTX *mdctx = NULL;
421 unsigned int hashlenui;
422 const SSL_CIPHER *sslcipher = SSL_SESSION_get0_cipher(s->session);
424 insecret = s->early_secret;
425 label = client_early_traffic;
426 labellen = sizeof(client_early_traffic) - 1;
427 log_label = CLIENT_EARLY_LABEL;
429 handlen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata);
431 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
432 SSL_F_TLS13_CHANGE_CIPHER_STATE,
433 SSL_R_BAD_HANDSHAKE_LENGTH);
437 if (s->early_data_state == SSL_EARLY_DATA_CONNECTING
438 && s->max_early_data > 0
439 && s->session->ext.max_early_data == 0) {
441 * If we are attempting to send early data, and we've decided to
442 * actually do it but max_early_data in s->session is 0 then we
443 * must be using an external PSK.
445 if (!ossl_assert(s->psksession != NULL
446 && s->max_early_data ==
447 s->psksession->ext.max_early_data)) {
448 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
449 SSL_F_TLS13_CHANGE_CIPHER_STATE,
450 ERR_R_INTERNAL_ERROR);
453 sslcipher = SSL_SESSION_get0_cipher(s->psksession);
455 if (sslcipher == NULL) {
456 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
457 SSL_F_TLS13_CHANGE_CIPHER_STATE, SSL_R_BAD_PSK);
462 * We need to calculate the handshake digest using the digest from
463 * the session. We haven't yet selected our ciphersuite so we can't
464 * use ssl_handshake_md().
466 mdctx = EVP_MD_CTX_new();
468 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
469 SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
472 cipher = EVP_get_cipherbynid(SSL_CIPHER_get_cipher_nid(sslcipher));
473 md = ssl_md(sslcipher->algorithm2);
474 if (md == NULL || !EVP_DigestInit_ex(mdctx, md, NULL)
475 || !EVP_DigestUpdate(mdctx, hdata, handlen)
476 || !EVP_DigestFinal_ex(mdctx, hashval, &hashlenui)) {
477 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
478 SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
479 EVP_MD_CTX_free(mdctx);
483 EVP_MD_CTX_free(mdctx);
484 } else if (which & SSL3_CC_HANDSHAKE) {
485 insecret = s->handshake_secret;
486 finsecret = s->client_finished_secret;
487 finsecretlen = EVP_MD_size(ssl_handshake_md(s));
488 label = client_handshake_traffic;
489 labellen = sizeof(client_handshake_traffic) - 1;
490 log_label = CLIENT_HANDSHAKE_LABEL;
492 * The handshake hash used for the server read/client write handshake
493 * traffic secret is the same as the hash for the server
494 * write/client read handshake traffic secret. However, if we
495 * processed early data then we delay changing the server
496 * read/client write cipher state until later, and the handshake
497 * hashes have moved on. Therefore we use the value saved earlier
498 * when we did the server write/client read change cipher state.
500 hash = s->handshake_traffic_hash;
502 insecret = s->master_secret;
503 label = client_application_traffic;
504 labellen = sizeof(client_application_traffic) - 1;
505 log_label = CLIENT_APPLICATION_LABEL;
507 * For this we only use the handshake hashes up until the server
508 * Finished hash. We do not include the client's Finished, which is
509 * what ssl_handshake_hash() would give us. Instead we use the
510 * previously saved value.
512 hash = s->server_finished_hash;
515 /* Early data never applies to client-read/server-write */
516 if (which & SSL3_CC_HANDSHAKE) {
517 insecret = s->handshake_secret;
518 finsecret = s->server_finished_secret;
519 finsecretlen = EVP_MD_size(ssl_handshake_md(s));
520 label = server_handshake_traffic;
521 labellen = sizeof(server_handshake_traffic) - 1;
522 log_label = SERVER_HANDSHAKE_LABEL;
524 insecret = s->master_secret;
525 label = server_application_traffic;
526 labellen = sizeof(server_application_traffic) - 1;
527 log_label = SERVER_APPLICATION_LABEL;
531 if (!(which & SSL3_CC_EARLY)) {
532 md = ssl_handshake_md(s);
533 cipher = s->s3->tmp.new_sym_enc;
534 if (!ssl3_digest_cached_records(s, 1)
535 || !ssl_handshake_hash(s, hashval, sizeof(hashval), &hashlen)) {
536 /* SSLfatal() already called */;
542 * Save the hash of handshakes up to now for use when we calculate the
543 * client application traffic secret
545 if (label == server_application_traffic)
546 memcpy(s->server_finished_hash, hashval, hashlen);
548 if (label == server_handshake_traffic)
549 memcpy(s->handshake_traffic_hash, hashval, hashlen);
551 if (label == client_application_traffic) {
553 * We also create the resumption master secret, but this time use the
554 * hash for the whole handshake including the Client Finished
556 if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
557 resumption_master_secret,
558 sizeof(resumption_master_secret) - 1,
559 hashval, hashlen, s->session->master_key,
561 /* SSLfatal() already called */
564 s->session->master_key_length = hashlen;
566 /* Now we create the exporter master secret */
567 if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
568 exporter_master_secret,
569 sizeof(exporter_master_secret) - 1,
570 hash, hashlen, s->exporter_master_secret,
572 /* SSLfatal() already called */
577 if (!derive_secret_key_and_iv(s, which & SSL3_CC_WRITE, md, cipher,
578 insecret, hash, label, labellen, secret, iv,
580 /* SSLfatal() already called */
584 if (label == server_application_traffic)
585 memcpy(s->server_app_traffic_secret, secret, hashlen);
586 else if (label == client_application_traffic)
587 memcpy(s->client_app_traffic_secret, secret, hashlen);
589 if (!ssl_log_secret(s, log_label, secret, hashlen)) {
590 /* SSLfatal() already called */
594 if (finsecret != NULL
595 && !tls13_derive_finishedkey(s, ssl_handshake_md(s), secret,
596 finsecret, finsecretlen)) {
597 /* SSLfatal() already called */
603 OPENSSL_cleanse(secret, sizeof(secret));
607 int tls13_update_key(SSL *s, int sending)
609 static const unsigned char application_traffic[] = "traffic upd";
610 const EVP_MD *md = ssl_handshake_md(s);
611 size_t hashlen = EVP_MD_size(md);
612 unsigned char *insecret, *iv;
613 unsigned char secret[EVP_MAX_MD_SIZE];
614 EVP_CIPHER_CTX *ciph_ctx;
617 if (s->server == sending)
618 insecret = s->server_app_traffic_secret;
620 insecret = s->client_app_traffic_secret;
624 ciph_ctx = s->enc_write_ctx;
625 RECORD_LAYER_reset_write_sequence(&s->rlayer);
628 ciph_ctx = s->enc_read_ctx;
629 RECORD_LAYER_reset_read_sequence(&s->rlayer);
632 if (!derive_secret_key_and_iv(s, sending, ssl_handshake_md(s),
633 s->s3->tmp.new_sym_enc, insecret, NULL,
635 sizeof(application_traffic) - 1, secret, iv,
637 /* SSLfatal() already called */
641 memcpy(insecret, secret, hashlen);
645 OPENSSL_cleanse(secret, sizeof(secret));
649 int tls13_alert_code(int code)
651 if (code == SSL_AD_MISSING_EXTENSION)
654 return tls1_alert_code(code);
657 int tls13_export_keying_material(SSL *s, unsigned char *out, size_t olen,
658 const char *label, size_t llen,
659 const unsigned char *context,
660 size_t contextlen, int use_context)
662 unsigned char exportsecret[EVP_MAX_MD_SIZE];
663 static const unsigned char exporterlabel[] = "exporter";
664 unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE];
665 const EVP_MD *md = ssl_handshake_md(s);
666 EVP_MD_CTX *ctx = EVP_MD_CTX_new();
667 unsigned int hashsize, datalen;
670 if (ctx == NULL || !SSL_is_init_finished(s))
676 if (EVP_DigestInit_ex(ctx, md, NULL) <= 0
677 || EVP_DigestUpdate(ctx, context, contextlen) <= 0
678 || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0
679 || EVP_DigestInit_ex(ctx, md, NULL) <= 0
680 || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0
681 || !tls13_hkdf_expand(s, md, s->exporter_master_secret,
682 (const unsigned char *)label, llen,
683 data, datalen, exportsecret, hashsize)
684 || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel,
685 sizeof(exporterlabel) - 1, hash, hashsize,
691 EVP_MD_CTX_free(ctx);