ssl/tls13_enc.c

   1 /*
   2  * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   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
   8  */
   9
  10 #include <stdlib.h>
  11 #include "ssl_locl.h"
  12 #include "internal/cryptlib.h"
  13 #include <openssl/evp.h>
  14 #include <openssl/kdf.h>
  15
  16 #define TLS13_MAX_LABEL_LEN     246
  17
  18 /* Always filled with zeros */
  19 static const unsigned char default_zeros[EVP_MAX_MD_SIZE];
  20
  21 /*
  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.
  26  */
  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)
  31 {
  32     const unsigned char label_prefix[] = "tls13 ";
  33     EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
  34     int ret;
  35     size_t hkdflabellen;
  36     size_t hashlen;
  37     /*
  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
  40      */
  41     unsigned char hkdflabel[sizeof(uint16_t) + sizeof(uint8_t) +
  42                             + sizeof(label_prefix) + TLS13_MAX_LABEL_LEN
  43                             + EVP_MAX_MD_SIZE];
  44     WPACKET pkt;
  45
  46     if (pctx == NULL)
  47         return 0;
  48
  49     hashlen = EVP_MD_size(md);
  50
  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         return 0;
  63     }
  64
  65     ret = EVP_PKEY_derive_init(pctx) <= 0
  66             || EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXPAND_ONLY)
  67                <= 0
  68             || EVP_PKEY_CTX_set_hkdf_md(pctx, md) <= 0
  69             || EVP_PKEY_CTX_set1_hkdf_key(pctx, secret, hashlen) <= 0
  70             || EVP_PKEY_CTX_add1_hkdf_info(pctx, hkdflabel, hkdflabellen) <= 0
  71             || EVP_PKEY_derive(pctx, out, &outlen) <= 0;
  72
  73     EVP_PKEY_CTX_free(pctx);
  74
  75     return ret == 0;
  76 }
  77
  78 /*
  79  * Given a |secret| generate a |key| of length |keylen| bytes. Returns 1 on
  80  * success  0 on failure.
  81  */
  82 int tls13_derive_key(SSL *s, const EVP_MD *md, const unsigned char *secret,
  83                      unsigned char *key, size_t keylen)
  84 {
  85     static const unsigned char keylabel[] = "key";
  86
  87     return tls13_hkdf_expand(s, md, secret, keylabel, sizeof(keylabel) - 1,
  88                              NULL, 0, key, keylen);
  89 }
  90
  91 /*
  92  * Given a |secret| generate an |iv| of length |ivlen| bytes. Returns 1 on
  93  * success  0 on failure.
  94  */
  95 int tls13_derive_iv(SSL *s, const EVP_MD *md, const unsigned char *secret,
  96                     unsigned char *iv, size_t ivlen)
  97 {
  98     static const unsigned char ivlabel[] = "iv";
  99
 100     return tls13_hkdf_expand(s, md, secret, ivlabel, sizeof(ivlabel) - 1,
 101                              NULL, 0, iv, ivlen);
 102 }
 103
 104 int tls13_derive_finishedkey(SSL *s, const EVP_MD *md,
 105                              const unsigned char *secret,
 106                              unsigned char *fin, size_t finlen)
 107 {
 108     static const unsigned char finishedlabel[] = "finished";
 109
 110     return tls13_hkdf_expand(s, md, secret, finishedlabel,
 111                              sizeof(finishedlabel) - 1, NULL, 0, fin, finlen);
 112 }
 113
 114 /*
 115  * Given the previous secret |prevsecret| and a new input secret |insecret| of
 116  * length |insecretlen|, generate a new secret and store it in the location
 117  * pointed to by |outsecret|. Returns 1 on success  0 on failure.
 118  */
 119 int tls13_generate_secret(SSL *s, const EVP_MD *md,
 120                           const unsigned char *prevsecret,
 121                           const unsigned char *insecret,
 122                           size_t insecretlen,
 123                           unsigned char *outsecret)
 124 {
 125     size_t mdlen, prevsecretlen;
 126     int ret;
 127     EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
 128     static const char derived_secret_label[] = "derived";
 129     unsigned char preextractsec[EVP_MAX_MD_SIZE];
 130
 131     if (pctx == NULL)
 132         return 0;
 133
 134     mdlen = EVP_MD_size(md);
 135
 136     if (insecret == NULL) {
 137         insecret = default_zeros;
 138         insecretlen = mdlen;
 139     }
 140     if (prevsecret == NULL) {
 141         prevsecret = default_zeros;
 142         prevsecretlen = 0;
 143     } else {
 144         EVP_MD_CTX *mctx = EVP_MD_CTX_new();
 145         unsigned char hash[EVP_MAX_MD_SIZE];
 146
 147         /* The pre-extract derive step uses a hash of no messages */
 148         if (mctx == NULL
 149                 || EVP_DigestInit_ex(mctx, md, NULL) <= 0
 150                 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
 151             EVP_MD_CTX_free(mctx);
 152             EVP_PKEY_CTX_free(pctx);
 153             return 0;
 154         }
 155         EVP_MD_CTX_free(mctx);
 156
 157         /* Generate the pre-extract secret */
 158         if (!tls13_hkdf_expand(s, md, prevsecret,
 159                                (unsigned char *)derived_secret_label,
 160                                sizeof(derived_secret_label) - 1, hash, mdlen,
 161                                preextractsec, mdlen)) {
 162             EVP_PKEY_CTX_free(pctx);
 163             return 0;
 164         }
 165
 166         prevsecret = preextractsec;
 167         prevsecretlen = mdlen;
 168     }
 169
 170     ret = EVP_PKEY_derive_init(pctx) <= 0
 171             || EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY)
 172                <= 0
 173             || EVP_PKEY_CTX_set_hkdf_md(pctx, md) <= 0
 174             || EVP_PKEY_CTX_set1_hkdf_key(pctx, insecret, insecretlen) <= 0
 175             || EVP_PKEY_CTX_set1_hkdf_salt(pctx, prevsecret, prevsecretlen)
 176                <= 0
 177             || EVP_PKEY_derive(pctx, outsecret, &mdlen)
 178                <= 0;
 179
 180     EVP_PKEY_CTX_free(pctx);
 181     if (prevsecret == preextractsec)
 182         OPENSSL_cleanse(preextractsec, mdlen);
 183     return ret == 0;
 184 }
 185
 186 /*
 187  * Given an input secret |insecret| of length |insecretlen| generate the
 188  * handshake secret. This requires the early secret to already have been
 189  * generated. Returns 1 on success  0 on failure.
 190  */
 191 int tls13_generate_handshake_secret(SSL *s, const unsigned char *insecret,
 192                                 size_t insecretlen)
 193 {
 194     return tls13_generate_secret(s, ssl_handshake_md(s), s->early_secret,
 195                                  insecret, insecretlen,
 196                                  (unsigned char *)&s->handshake_secret);
 197 }
 198
 199 /*
 200  * Given the handshake secret |prev| of length |prevlen| generate the master
 201  * secret and store its length in |*secret_size|. Returns 1 on success  0 on
 202  * failure.
 203  */
 204 int tls13_generate_master_secret(SSL *s, unsigned char *out,
 205                                  unsigned char *prev, size_t prevlen,
 206                                  size_t *secret_size)
 207 {
 208     const EVP_MD *md = ssl_handshake_md(s);
 209
 210     *secret_size = EVP_MD_size(md);
 211     return tls13_generate_secret(s, md, prev, NULL, 0, out);
 212 }
 213
 214 /*
 215  * Generates the mac for the Finished message. Returns the length of the MAC or
 216  * 0 on error.
 217  */
 218 size_t tls13_final_finish_mac(SSL *s, const char *str, size_t slen,
 219                              unsigned char *out)
 220 {
 221     const EVP_MD *md = ssl_handshake_md(s);
 222     unsigned char hash[EVP_MAX_MD_SIZE];
 223     size_t hashlen, ret = 0;
 224     EVP_PKEY *key = NULL;
 225     EVP_MD_CTX *ctx = EVP_MD_CTX_new();
 226
 227     if (!ssl_handshake_hash(s, hash, sizeof(hash), &hashlen))
 228         goto err;
 229
 230     if (str == s->method->ssl3_enc->server_finished_label)
 231         key = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL,
 232                                    s->server_finished_secret, hashlen);
 233     else
 234         key = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL,
 235                                    s->client_finished_secret, hashlen);
 236
 237     if (key == NULL
 238             || ctx == NULL
 239             || EVP_DigestSignInit(ctx, NULL, md, NULL, key) <= 0
 240             || EVP_DigestSignUpdate(ctx, hash, hashlen) <= 0
 241             || EVP_DigestSignFinal(ctx, out, &hashlen) <= 0)
 242         goto err;
 243
 244     ret = hashlen;
 245  err:
 246     EVP_PKEY_free(key);
 247     EVP_MD_CTX_free(ctx);
 248     return ret;
 249 }
 250
 251 /*
 252  * There isn't really a key block in TLSv1.3, but we still need this function
 253  * for initialising the cipher and hash. Returns 1 on success or 0 on failure.
 254  */
 255 int tls13_setup_key_block(SSL *s)
 256 {
 257     const EVP_CIPHER *c;
 258     const EVP_MD *hash;
 259     int mac_type = NID_undef;
 260
 261     s->session->cipher = s->s3->tmp.new_cipher;
 262     if (!ssl_cipher_get_evp
 263         (s->session, &c, &hash, &mac_type, NULL, NULL, 0)) {
 264         SSLerr(SSL_F_TLS13_SETUP_KEY_BLOCK, SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
 265         return 0;
 266     }
 267
 268     s->s3->tmp.new_sym_enc = c;
 269     s->s3->tmp.new_hash = hash;
 270
 271     return 1;
 272 }
 273
 274 static int derive_secret_key_and_iv(SSL *s, int sending, const EVP_MD *md,
 275                                     const EVP_CIPHER *ciph,
 276                                     const unsigned char *insecret,
 277                                     const unsigned char *hash,
 278                                     const unsigned char *label,
 279                                     size_t labellen, unsigned char *secret,
 280                                     unsigned char *iv, EVP_CIPHER_CTX *ciph_ctx)
 281 {
 282     unsigned char key[EVP_MAX_KEY_LENGTH];
 283     size_t ivlen, keylen, taglen;
 284     size_t hashlen = EVP_MD_size(md);
 285
 286     if (!tls13_hkdf_expand(s, md, insecret, label, labellen, hash, hashlen,
 287                            secret, hashlen)) {
 288         SSLerr(SSL_F_DERIVE_SECRET_KEY_AND_IV, ERR_R_INTERNAL_ERROR);
 289         goto err;
 290     }
 291
 292     /* TODO(size_t): convert me */
 293     keylen = EVP_CIPHER_key_length(ciph);
 294     if (EVP_CIPHER_mode(ciph) == EVP_CIPH_CCM_MODE) {
 295         uint32_t algenc;
 296
 297         ivlen = EVP_CCM_TLS_IV_LEN;
 298         if (s->s3->tmp.new_cipher == NULL) {
 299             /* We've not selected a cipher yet - we must be doing early data */
 300             algenc = s->session->cipher->algorithm_enc;
 301         } else {
 302             algenc = s->s3->tmp.new_cipher->algorithm_enc;
 303         }
 304         if (algenc & (SSL_AES128CCM8 | SSL_AES256CCM8))
 305             taglen = EVP_CCM8_TLS_TAG_LEN;
 306          else
 307             taglen = EVP_CCM_TLS_TAG_LEN;
 308     } else {
 309         ivlen = EVP_CIPHER_iv_length(ciph);
 310         taglen = 0;
 311     }
 312
 313     if (!tls13_derive_key(s, md, secret, key, keylen)
 314             || !tls13_derive_iv(s, md, secret, iv, ivlen)) {
 315         SSLerr(SSL_F_DERIVE_SECRET_KEY_AND_IV, ERR_R_INTERNAL_ERROR);
 316         goto err;
 317     }
 318
 319     if (EVP_CipherInit_ex(ciph_ctx, ciph, NULL, NULL, NULL, sending) <= 0
 320         || !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
 321         || (taglen != 0 && !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_TAG,
 322                                                 taglen, NULL))
 323         || EVP_CipherInit_ex(ciph_ctx, NULL, NULL, key, NULL, -1) <= 0) {
 324         SSLerr(SSL_F_DERIVE_SECRET_KEY_AND_IV, ERR_R_EVP_LIB);
 325         goto err;
 326     }
 327
 328     return 1;
 329  err:
 330     OPENSSL_cleanse(key, sizeof(key));
 331     return 0;
 332 }
 333
 334 int tls13_change_cipher_state(SSL *s, int which)
 335 {
 336     static const unsigned char client_early_traffic[] = "c e traffic";
 337     static const unsigned char client_handshake_traffic[] = "c hs traffic";
 338     static const unsigned char client_application_traffic[] = "c ap traffic";
 339     static const unsigned char server_handshake_traffic[] = "s hs traffic";
 340     static const unsigned char server_application_traffic[] = "s ap traffic";
 341     static const unsigned char exporter_master_secret[] = "exp master";
 342     static const unsigned char resumption_master_secret[] = "res master";
 343     unsigned char *iv;
 344     unsigned char secret[EVP_MAX_MD_SIZE];
 345     unsigned char hashval[EVP_MAX_MD_SIZE];
 346     unsigned char *hash = hashval;
 347     unsigned char *insecret;
 348     unsigned char *finsecret = NULL;
 349     const char *log_label = NULL;
 350     EVP_CIPHER_CTX *ciph_ctx;
 351     size_t finsecretlen = 0;
 352     const unsigned char *label;
 353     size_t labellen, hashlen = 0;
 354     int ret = 0;
 355     const EVP_MD *md = NULL;
 356     const EVP_CIPHER *cipher = NULL;
 357
 358     if (which & SSL3_CC_READ) {
 359         if (s->enc_read_ctx != NULL) {
 360             EVP_CIPHER_CTX_reset(s->enc_read_ctx);
 361         } else {
 362             s->enc_read_ctx = EVP_CIPHER_CTX_new();
 363             if (s->enc_read_ctx == NULL) {
 364                 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
 365                 goto err;
 366             }
 367         }
 368         ciph_ctx = s->enc_read_ctx;
 369         iv = s->read_iv;
 370
 371         RECORD_LAYER_reset_read_sequence(&s->rlayer);
 372     } else {
 373         if (s->enc_write_ctx != NULL) {
 374             EVP_CIPHER_CTX_reset(s->enc_write_ctx);
 375         } else {
 376             s->enc_write_ctx = EVP_CIPHER_CTX_new();
 377             if (s->enc_write_ctx == NULL) {
 378                 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
 379                 goto err;
 380             }
 381         }
 382         ciph_ctx = s->enc_write_ctx;
 383         iv = s->write_iv;
 384
 385         RECORD_LAYER_reset_write_sequence(&s->rlayer);
 386     }
 387
 388     if (((which & SSL3_CC_CLIENT) && (which & SSL3_CC_WRITE))
 389             || ((which & SSL3_CC_SERVER) && (which & SSL3_CC_READ))) {
 390         if (which & SSL3_CC_EARLY) {
 391             EVP_MD_CTX *mdctx = NULL;
 392             long handlen;
 393             void *hdata;
 394             unsigned int hashlenui;
 395             const SSL_CIPHER *sslcipher = SSL_SESSION_get0_cipher(s->session);
 396
 397             insecret = s->early_secret;
 398             label = client_early_traffic;
 399             labellen = sizeof(client_early_traffic) - 1;
 400             log_label = CLIENT_EARLY_LABEL;
 401
 402             handlen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata);
 403             if (handlen <= 0) {
 404                 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE,
 405                        SSL_R_BAD_HANDSHAKE_LENGTH);
 406                 goto err;
 407             }
 408
 409             if (s->early_data_state == SSL_EARLY_DATA_CONNECTING
 410                     && s->max_early_data > 0
 411                     && s->session->ext.max_early_data == 0) {
 412                 /*
 413                  * If we are attempting to send early data, and we've decided to
 414                  * actually do it but max_early_data in s->session is 0 then we
 415                  * must be using an external PSK.
 416                  */
 417                 if (!ossl_assert(s->psksession != NULL
 418                         && s->max_early_data ==
 419                            s->psksession->ext.max_early_data)) {
 420                     SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE,
 421                            ERR_R_INTERNAL_ERROR);
 422                     goto err;
 423                 }
 424                 sslcipher = SSL_SESSION_get0_cipher(s->psksession);
 425             }
 426             if (sslcipher == NULL) {
 427                 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, SSL_R_BAD_PSK);
 428                 goto err;
 429             }
 430
 431             /*
 432              * We need to calculate the handshake digest using the digest from
 433              * the session. We haven't yet selected our ciphersuite so we can't
 434              * use ssl_handshake_md().
 435              */
 436             mdctx = EVP_MD_CTX_new();
 437             if (mdctx == NULL) {
 438                 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
 439                 goto err;
 440             }
 441             cipher = EVP_get_cipherbynid(SSL_CIPHER_get_cipher_nid(sslcipher));
 442             md = ssl_md(sslcipher->algorithm2);
 443             if (md == NULL || !EVP_DigestInit_ex(mdctx, md, NULL)
 444                     || !EVP_DigestUpdate(mdctx, hdata, handlen)
 445                     || !EVP_DigestFinal_ex(mdctx, hashval, &hashlenui)) {
 446                 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
 447                 EVP_MD_CTX_free(mdctx);
 448                 goto err;
 449             }
 450             hashlen = hashlenui;
 451             EVP_MD_CTX_free(mdctx);
 452         } else if (which & SSL3_CC_HANDSHAKE) {
 453             insecret = s->handshake_secret;
 454             finsecret = s->client_finished_secret;
 455             finsecretlen = EVP_MD_size(ssl_handshake_md(s));
 456             label = client_handshake_traffic;
 457             labellen = sizeof(client_handshake_traffic) - 1;
 458             log_label = CLIENT_HANDSHAKE_LABEL;
 459             /*
 460              * The handshake hash used for the server read/client write handshake
 461              * traffic secret is the same as the hash for the server
 462              * write/client read handshake traffic secret. However, if we
 463              * processed early data then we delay changing the server
 464              * read/client write cipher state until later, and the handshake
 465              * hashes have moved on. Therefore we use the value saved earlier
 466              * when we did the server write/client read change cipher state.
 467              */
 468             hash = s->handshake_traffic_hash;
 469         } else {
 470             insecret = s->master_secret;
 471             label = client_application_traffic;
 472             labellen = sizeof(client_application_traffic) - 1;
 473             log_label = CLIENT_APPLICATION_LABEL;
 474             /*
 475              * For this we only use the handshake hashes up until the server
 476              * Finished hash. We do not include the client's Finished, which is
 477              * what ssl_handshake_hash() would give us. Instead we use the
 478              * previously saved value.
 479              */
 480             hash = s->server_finished_hash;
 481         }
 482     } else {
 483         /* Early data never applies to client-read/server-write */
 484         if (which & SSL3_CC_HANDSHAKE) {
 485             insecret = s->handshake_secret;
 486             finsecret = s->server_finished_secret;
 487             finsecretlen = EVP_MD_size(ssl_handshake_md(s));
 488             label = server_handshake_traffic;
 489             labellen = sizeof(server_handshake_traffic) - 1;
 490             log_label = SERVER_HANDSHAKE_LABEL;
 491         } else {
 492             insecret = s->master_secret;
 493             label = server_application_traffic;
 494             labellen = sizeof(server_application_traffic) - 1;
 495             log_label = SERVER_APPLICATION_LABEL;
 496         }
 497     }
 498
 499     if (!(which & SSL3_CC_EARLY)) {
 500         md = ssl_handshake_md(s);
 501         cipher = s->s3->tmp.new_sym_enc;
 502         if (!ssl3_digest_cached_records(s, 1)
 503                 || !ssl_handshake_hash(s, hashval, sizeof(hashval), &hashlen)) {
 504             SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
 505             goto err;
 506         }
 507     }
 508
 509     /*
 510      * Save the hash of handshakes up to now for use when we calculate the
 511      * client application traffic secret
 512      */
 513     if (label == server_application_traffic)
 514         memcpy(s->server_finished_hash, hashval, hashlen);
 515
 516     if (label == server_handshake_traffic)
 517         memcpy(s->handshake_traffic_hash, hashval, hashlen);
 518
 519     if (label == client_application_traffic) {
 520         /*
 521          * We also create the resumption master secret, but this time use the
 522          * hash for the whole handshake including the Client Finished
 523          */
 524         if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
 525                                resumption_master_secret,
 526                                sizeof(resumption_master_secret) - 1,
 527                                hashval, hashlen, s->session->master_key,
 528                                hashlen)) {
 529             SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
 530             goto err;
 531         }
 532         s->session->master_key_length = hashlen;
 533
 534         /* Now we create the exporter master secret */
 535         if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
 536                                exporter_master_secret,
 537                                sizeof(exporter_master_secret) - 1,
 538                                hash, hashlen, s->exporter_master_secret,
 539                                hashlen)) {
 540             SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
 541             goto err;
 542         }
 543     }
 544
 545     if (!derive_secret_key_and_iv(s, which & SSL3_CC_WRITE, md, cipher,
 546                                   insecret, hash, label, labellen, secret, iv,
 547                                   ciph_ctx)) {
 548         goto err;
 549     }
 550
 551     if (label == server_application_traffic)
 552         memcpy(s->server_app_traffic_secret, secret, hashlen);
 553     else if (label == client_application_traffic)
 554         memcpy(s->client_app_traffic_secret, secret, hashlen);
 555
 556     if (!ssl_log_secret(s, log_label, secret, hashlen)) {
 557         SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
 558         goto err;
 559     }
 560
 561     if (finsecret != NULL
 562             && !tls13_derive_finishedkey(s, ssl_handshake_md(s), secret,
 563                                          finsecret, finsecretlen)) {
 564         SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
 565         goto err;
 566     }
 567
 568     ret = 1;
 569  err:
 570     OPENSSL_cleanse(secret, sizeof(secret));
 571     return ret;
 572 }
 573
 574 int tls13_update_key(SSL *s, int sending)
 575 {
 576     static const unsigned char application_traffic[] = "traffic upd";
 577     const EVP_MD *md = ssl_handshake_md(s);
 578     size_t hashlen = EVP_MD_size(md);
 579     unsigned char *insecret, *iv;
 580     unsigned char secret[EVP_MAX_MD_SIZE];
 581     EVP_CIPHER_CTX *ciph_ctx;
 582     int ret = 0;
 583
 584     if (s->server == sending)
 585         insecret = s->server_app_traffic_secret;
 586     else
 587         insecret = s->client_app_traffic_secret;
 588
 589     if (sending) {
 590         iv = s->write_iv;
 591         ciph_ctx = s->enc_write_ctx;
 592         RECORD_LAYER_reset_write_sequence(&s->rlayer);
 593     } else {
 594         iv = s->read_iv;
 595         ciph_ctx = s->enc_read_ctx;
 596         RECORD_LAYER_reset_read_sequence(&s->rlayer);
 597     }
 598
 599     if (!derive_secret_key_and_iv(s, sending, ssl_handshake_md(s),
 600                                   s->s3->tmp.new_sym_enc, insecret, NULL,
 601                                   application_traffic,
 602                                   sizeof(application_traffic) - 1, secret, iv,
 603                                   ciph_ctx))
 604         goto err;
 605
 606     memcpy(insecret, secret, hashlen);
 607
 608     ret = 1;
 609  err:
 610     OPENSSL_cleanse(secret, sizeof(secret));
 611     return ret;
 612 }
 613
 614 int tls13_alert_code(int code)
 615 {
 616     if (code == SSL_AD_MISSING_EXTENSION)
 617         return code;
 618
 619     return tls1_alert_code(code);
 620 }
 621
 622 int tls13_export_keying_material(SSL *s, unsigned char *out, size_t olen,
 623                                  const char *label, size_t llen,
 624                                  const unsigned char *context,
 625                                  size_t contextlen, int use_context)
 626 {
 627     unsigned char exportsecret[EVP_MAX_MD_SIZE];
 628     static const unsigned char exporterlabel[] = "exporter";
 629     unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE];
 630     const EVP_MD *md = ssl_handshake_md(s);
 631     EVP_MD_CTX *ctx = EVP_MD_CTX_new();
 632     unsigned int hashsize, datalen;
 633     int ret = 0;
 634
 635     if (ctx == NULL || !SSL_is_init_finished(s))
 636         goto err;
 637
 638     if (!use_context)
 639         contextlen = 0;
 640
 641     if (EVP_DigestInit_ex(ctx, md, NULL) <= 0
 642             || EVP_DigestUpdate(ctx, context, contextlen) <= 0
 643             || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0
 644             || EVP_DigestInit_ex(ctx, md, NULL) <= 0
 645             || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0
 646             || !tls13_hkdf_expand(s, md, s->exporter_master_secret,
 647                                   (const unsigned char *)label, llen,
 648                                   data, datalen, exportsecret, hashsize)
 649             || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel,
 650                                   sizeof(exporterlabel) - 1, hash, hashsize,
 651                                   out, olen))
 652         goto err;
 653
 654     ret = 1;
 655  err:
 656     EVP_MD_CTX_free(ctx);
 657     return ret;
 658 }