ssl/tls13_enc.c

   1 /*
   2  * Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (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     249
  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. Any errors will be treated as fatal if
  26  * |fatal| is set. Returns 1 on success  0 on failure.
  27  */
  28 int tls13_hkdf_expand(SSL *s, const EVP_MD *md, const unsigned char *secret,
  29                              const unsigned char *label, size_t labellen,
  30                              const unsigned char *data, size_t datalen,
  31                              unsigned char *out, size_t outlen, int fatal)
  32 {
  33     static const unsigned char label_prefix[] = "tls13 ";
  34     EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
  35     int ret;
  36     size_t hkdflabellen;
  37     size_t hashlen;
  38     /*
  39      * 2 bytes for length of derived secret + 1 byte for length of combined
  40      * prefix and label + bytes for the label itself + 1 byte length of hash
  41      * + bytes for the hash itself
  42      */
  43     unsigned char hkdflabel[sizeof(uint16_t) + sizeof(uint8_t) +
  44                             + sizeof(label_prefix) + TLS13_MAX_LABEL_LEN
  45                             + 1 + EVP_MAX_MD_SIZE];
  46     WPACKET pkt;
  47
  48     if (pctx == NULL)
  49         return 0;
  50
  51     if (labellen > TLS13_MAX_LABEL_LEN) {
  52         if (fatal) {
  53             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
  54                      ERR_R_INTERNAL_ERROR);
  55         } else {
  56             /*
  57              * Probably we have been called from SSL_export_keying_material(),
  58              * or SSL_export_keying_material_early().
  59              */
  60             SSLerr(SSL_F_TLS13_HKDF_EXPAND, SSL_R_TLS_ILLEGAL_EXPORTER_LABEL);
  61         }
  62         EVP_PKEY_CTX_free(pctx);
  63         return 0;
  64     }
  65
  66     hashlen = EVP_MD_size(md);
  67
  68     if (!WPACKET_init_static_len(&pkt, hkdflabel, sizeof(hkdflabel), 0)
  69             || !WPACKET_put_bytes_u16(&pkt, outlen)
  70             || !WPACKET_start_sub_packet_u8(&pkt)
  71             || !WPACKET_memcpy(&pkt, label_prefix, sizeof(label_prefix) - 1)
  72             || !WPACKET_memcpy(&pkt, label, labellen)
  73             || !WPACKET_close(&pkt)
  74             || !WPACKET_sub_memcpy_u8(&pkt, data, (data == NULL) ? 0 : datalen)
  75             || !WPACKET_get_total_written(&pkt, &hkdflabellen)
  76             || !WPACKET_finish(&pkt)) {
  77         EVP_PKEY_CTX_free(pctx);
  78         WPACKET_cleanup(&pkt);
  79         if (fatal)
  80             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
  81                      ERR_R_INTERNAL_ERROR);
  82         else
  83             SSLerr(SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR);
  84         return 0;
  85     }
  86
  87     ret = EVP_PKEY_derive_init(pctx) <= 0
  88             || EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXPAND_ONLY)
  89                <= 0
  90             || EVP_PKEY_CTX_set_hkdf_md(pctx, md) <= 0
  91             || EVP_PKEY_CTX_set1_hkdf_key(pctx, secret, hashlen) <= 0
  92             || EVP_PKEY_CTX_add1_hkdf_info(pctx, hkdflabel, hkdflabellen) <= 0
  93             || EVP_PKEY_derive(pctx, out, &outlen) <= 0;
  94
  95     EVP_PKEY_CTX_free(pctx);
  96
  97     if (ret != 0) {
  98         if (fatal)
  99             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
 100                      ERR_R_INTERNAL_ERROR);
 101         else
 102             SSLerr(SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR);
 103     }
 104
 105     return ret == 0;
 106 }
 107
 108 /*
 109  * Given a |secret| generate a |key| of length |keylen| bytes. Returns 1 on
 110  * success  0 on failure.
 111  */
 112 int tls13_derive_key(SSL *s, const EVP_MD *md, const unsigned char *secret,
 113                      unsigned char *key, size_t keylen)
 114 {
 115     static const unsigned char keylabel[] = "key";
 116
 117     return tls13_hkdf_expand(s, md, secret, keylabel, sizeof(keylabel) - 1,
 118                              NULL, 0, key, keylen, 1);
 119 }
 120
 121 /*
 122  * Given a |secret| generate an |iv| of length |ivlen| bytes. Returns 1 on
 123  * success  0 on failure.
 124  */
 125 int tls13_derive_iv(SSL *s, const EVP_MD *md, const unsigned char *secret,
 126                     unsigned char *iv, size_t ivlen)
 127 {
 128     static const unsigned char ivlabel[] = "iv";
 129
 130     return tls13_hkdf_expand(s, md, secret, ivlabel, sizeof(ivlabel) - 1,
 131                              NULL, 0, iv, ivlen, 1);
 132 }
 133
 134 int tls13_derive_finishedkey(SSL *s, const EVP_MD *md,
 135                              const unsigned char *secret,
 136                              unsigned char *fin, size_t finlen)
 137 {
 138     static const unsigned char finishedlabel[] = "finished";
 139
 140     return tls13_hkdf_expand(s, md, secret, finishedlabel,
 141                              sizeof(finishedlabel) - 1, NULL, 0, fin, finlen, 1);
 142 }
 143
 144 /*
 145  * Given the previous secret |prevsecret| and a new input secret |insecret| of
 146  * length |insecretlen|, generate a new secret and store it in the location
 147  * pointed to by |outsecret|. Returns 1 on success  0 on failure.
 148  */
 149 int tls13_generate_secret(SSL *s, const EVP_MD *md,
 150                           const unsigned char *prevsecret,
 151                           const unsigned char *insecret,
 152                           size_t insecretlen,
 153                           unsigned char *outsecret)
 154 {
 155     size_t mdlen, prevsecretlen;
 156     int mdleni;
 157     int ret;
 158     EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
 159     static const char derived_secret_label[] = "derived";
 160     unsigned char preextractsec[EVP_MAX_MD_SIZE];
 161
 162     if (pctx == NULL) {
 163         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
 164                  ERR_R_INTERNAL_ERROR);
 165         return 0;
 166     }
 167
 168     mdleni = EVP_MD_size(md);
 169     /* Ensure cast to size_t is safe */
 170     if (!ossl_assert(mdleni >= 0)) {
 171         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
 172                  ERR_R_INTERNAL_ERROR);
 173         return 0;
 174     }
 175     mdlen = (size_t)mdleni;
 176
 177     if (insecret == NULL) {
 178         insecret = default_zeros;
 179         insecretlen = mdlen;
 180     }
 181     if (prevsecret == NULL) {
 182         prevsecret = default_zeros;
 183         prevsecretlen = 0;
 184     } else {
 185         EVP_MD_CTX *mctx = EVP_MD_CTX_new();
 186         unsigned char hash[EVP_MAX_MD_SIZE];
 187
 188         /* The pre-extract derive step uses a hash of no messages */
 189         if (mctx == NULL
 190                 || EVP_DigestInit_ex(mctx, md, NULL) <= 0
 191                 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
 192             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
 193                      ERR_R_INTERNAL_ERROR);
 194             EVP_MD_CTX_free(mctx);
 195             EVP_PKEY_CTX_free(pctx);
 196             return 0;
 197         }
 198         EVP_MD_CTX_free(mctx);
 199
 200         /* Generate the pre-extract secret */
 201         if (!tls13_hkdf_expand(s, md, prevsecret,
 202                                (unsigned char *)derived_secret_label,
 203                                sizeof(derived_secret_label) - 1, hash, mdlen,
 204                                preextractsec, mdlen, 1)) {
 205             /* SSLfatal() already called */
 206             EVP_PKEY_CTX_free(pctx);
 207             return 0;
 208         }
 209
 210         prevsecret = preextractsec;
 211         prevsecretlen = mdlen;
 212     }
 213
 214     ret = EVP_PKEY_derive_init(pctx) <= 0
 215             || EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY)
 216                <= 0
 217             || EVP_PKEY_CTX_set_hkdf_md(pctx, md) <= 0
 218             || EVP_PKEY_CTX_set1_hkdf_key(pctx, insecret, insecretlen) <= 0
 219             || EVP_PKEY_CTX_set1_hkdf_salt(pctx, prevsecret, prevsecretlen)
 220                <= 0
 221             || EVP_PKEY_derive(pctx, outsecret, &mdlen)
 222                <= 0;
 223
 224     if (ret != 0)
 225         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
 226                  ERR_R_INTERNAL_ERROR);
 227
 228     EVP_PKEY_CTX_free(pctx);
 229     if (prevsecret == preextractsec)
 230         OPENSSL_cleanse(preextractsec, mdlen);
 231     return ret == 0;
 232 }
 233
 234 /*
 235  * Given an input secret |insecret| of length |insecretlen| generate the
 236  * handshake secret. This requires the early secret to already have been
 237  * generated. Returns 1 on success  0 on failure.
 238  */
 239 int tls13_generate_handshake_secret(SSL *s, const unsigned char *insecret,
 240                                 size_t insecretlen)
 241 {
 242     /* Calls SSLfatal() if required */
 243     return tls13_generate_secret(s, ssl_handshake_md(s), s->early_secret,
 244                                  insecret, insecretlen,
 245                                  (unsigned char *)&s->handshake_secret);
 246 }
 247
 248 /*
 249  * Given the handshake secret |prev| of length |prevlen| generate the master
 250  * secret and store its length in |*secret_size|. Returns 1 on success  0 on
 251  * failure.
 252  */
 253 int tls13_generate_master_secret(SSL *s, unsigned char *out,
 254                                  unsigned char *prev, size_t prevlen,
 255                                  size_t *secret_size)
 256 {
 257     const EVP_MD *md = ssl_handshake_md(s);
 258
 259     *secret_size = EVP_MD_size(md);
 260     /* Calls SSLfatal() if required */
 261     return tls13_generate_secret(s, md, prev, NULL, 0, out);
 262 }
 263
 264 /*
 265  * Generates the mac for the Finished message. Returns the length of the MAC or
 266  * 0 on error.
 267  */
 268 size_t tls13_final_finish_mac(SSL *s, const char *str, size_t slen,
 269                              unsigned char *out)
 270 {
 271     const EVP_MD *md = ssl_handshake_md(s);
 272     unsigned char hash[EVP_MAX_MD_SIZE];
 273     size_t hashlen, ret = 0;
 274     EVP_PKEY *key = NULL;
 275     EVP_MD_CTX *ctx = EVP_MD_CTX_new();
 276
 277     if (!ssl_handshake_hash(s, hash, sizeof(hash), &hashlen)) {
 278         /* SSLfatal() already called */
 279         goto err;
 280     }
 281
 282     if (str == s->method->ssl3_enc->server_finished_label) {
 283         key = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL,
 284                                            s->server_finished_secret, hashlen);
 285     } else if (SSL_IS_FIRST_HANDSHAKE(s)) {
 286         key = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL,
 287                                            s->client_finished_secret, hashlen);
 288     } else {
 289         unsigned char finsecret[EVP_MAX_MD_SIZE];
 290
 291         if (!tls13_derive_finishedkey(s, ssl_handshake_md(s),
 292                                       s->client_app_traffic_secret,
 293                                       finsecret, hashlen))
 294             goto err;
 295
 296         key = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL, finsecret,
 297                                            hashlen);
 298         OPENSSL_cleanse(finsecret, sizeof(finsecret));
 299     }
 300
 301     if (key == NULL
 302             || ctx == NULL
 303             || EVP_DigestSignInit(ctx, NULL, md, NULL, key) <= 0
 304             || EVP_DigestSignUpdate(ctx, hash, hashlen) <= 0
 305             || EVP_DigestSignFinal(ctx, out, &hashlen) <= 0) {
 306         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_FINAL_FINISH_MAC,
 307                  ERR_R_INTERNAL_ERROR);
 308         goto err;
 309     }
 310
 311     ret = hashlen;
 312  err:
 313     EVP_PKEY_free(key);
 314     EVP_MD_CTX_free(ctx);
 315     return ret;
 316 }
 317
 318 /*
 319  * There isn't really a key block in TLSv1.3, but we still need this function
 320  * for initialising the cipher and hash. Returns 1 on success or 0 on failure.
 321  */
 322 int tls13_setup_key_block(SSL *s)
 323 {
 324     const EVP_CIPHER *c;
 325     const EVP_MD *hash;
 326     int mac_type = NID_undef;
 327
 328     s->session->cipher = s->s3->tmp.new_cipher;
 329     if (!ssl_cipher_get_evp
 330         (s->session, &c, &hash, &mac_type, NULL, NULL, 0)) {
 331         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_SETUP_KEY_BLOCK,
 332                  SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
 333         return 0;
 334     }
 335
 336     s->s3->tmp.new_sym_enc = c;
 337     s->s3->tmp.new_hash = hash;
 338
 339     return 1;
 340 }
 341
 342 static int derive_secret_key_and_iv(SSL *s, int sending, const EVP_MD *md,
 343                                     const EVP_CIPHER *ciph,
 344                                     const unsigned char *insecret,
 345                                     const unsigned char *hash,
 346                                     const unsigned char *label,
 347                                     size_t labellen, unsigned char *secret,
 348                                     unsigned char *iv, EVP_CIPHER_CTX *ciph_ctx)
 349 {
 350     unsigned char key[EVP_MAX_KEY_LENGTH];
 351     size_t ivlen, keylen, taglen;
 352     int hashleni = EVP_MD_size(md);
 353     size_t hashlen;
 354
 355     /* Ensure cast to size_t is safe */
 356     if (!ossl_assert(hashleni >= 0)) {
 357         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DERIVE_SECRET_KEY_AND_IV,
 358                  ERR_R_EVP_LIB);
 359         goto err;
 360     }
 361     hashlen = (size_t)hashleni;
 362
 363     if (!tls13_hkdf_expand(s, md, insecret, label, labellen, hash, hashlen,
 364                            secret, hashlen, 1)) {
 365         /* SSLfatal() already called */
 366         goto err;
 367     }
 368
 369     /* TODO(size_t): convert me */
 370     keylen = EVP_CIPHER_key_length(ciph);
 371     if (EVP_CIPHER_mode(ciph) == EVP_CIPH_CCM_MODE) {
 372         uint32_t algenc;
 373
 374         ivlen = EVP_CCM_TLS_IV_LEN;
 375         if (s->s3->tmp.new_cipher == NULL) {
 376             /* We've not selected a cipher yet - we must be doing early data */
 377             algenc = s->session->cipher->algorithm_enc;
 378         } else {
 379             algenc = s->s3->tmp.new_cipher->algorithm_enc;
 380         }
 381         if (algenc & (SSL_AES128CCM8 | SSL_AES256CCM8))
 382             taglen = EVP_CCM8_TLS_TAG_LEN;
 383          else
 384             taglen = EVP_CCM_TLS_TAG_LEN;
 385     } else {
 386         ivlen = EVP_CIPHER_iv_length(ciph);
 387         taglen = 0;
 388     }
 389
 390     if (!tls13_derive_key(s, md, secret, key, keylen)
 391             || !tls13_derive_iv(s, md, secret, iv, ivlen)) {
 392         /* SSLfatal() already called */
 393         goto err;
 394     }
 395
 396     if (EVP_CipherInit_ex(ciph_ctx, ciph, NULL, NULL, NULL, sending) <= 0
 397         || !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
 398         || (taglen != 0 && !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_TAG,
 399                                                 taglen, NULL))
 400         || EVP_CipherInit_ex(ciph_ctx, NULL, NULL, key, NULL, -1) <= 0) {
 401         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DERIVE_SECRET_KEY_AND_IV,
 402                  ERR_R_EVP_LIB);
 403         goto err;
 404     }
 405
 406     return 1;
 407  err:
 408     OPENSSL_cleanse(key, sizeof(key));
 409     return 0;
 410 }
 411
 412 int tls13_change_cipher_state(SSL *s, int which)
 413 {
 414     static const unsigned char client_early_traffic[] = "c e traffic";
 415     static const unsigned char client_handshake_traffic[] = "c hs traffic";
 416     static const unsigned char client_application_traffic[] = "c ap traffic";
 417     static const unsigned char server_handshake_traffic[] = "s hs traffic";
 418     static const unsigned char server_application_traffic[] = "s ap traffic";
 419     static const unsigned char exporter_master_secret[] = "exp master";
 420     static const unsigned char resumption_master_secret[] = "res master";
 421     static const unsigned char early_exporter_master_secret[] = "e exp master";
 422     unsigned char *iv;
 423     unsigned char secret[EVP_MAX_MD_SIZE];
 424     unsigned char hashval[EVP_MAX_MD_SIZE];
 425     unsigned char *hash = hashval;
 426     unsigned char *insecret;
 427     unsigned char *finsecret = NULL;
 428     const char *log_label = NULL;
 429     EVP_CIPHER_CTX *ciph_ctx;
 430     size_t finsecretlen = 0;
 431     const unsigned char *label;
 432     size_t labellen, hashlen = 0;
 433     int ret = 0;
 434     const EVP_MD *md = NULL;
 435     const EVP_CIPHER *cipher = NULL;
 436
 437     if (which & SSL3_CC_READ) {
 438         if (s->enc_read_ctx != NULL) {
 439             EVP_CIPHER_CTX_reset(s->enc_read_ctx);
 440         } else {
 441             s->enc_read_ctx = EVP_CIPHER_CTX_new();
 442             if (s->enc_read_ctx == NULL) {
 443                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 444                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
 445                 goto err;
 446             }
 447         }
 448         ciph_ctx = s->enc_read_ctx;
 449         iv = s->read_iv;
 450
 451         RECORD_LAYER_reset_read_sequence(&s->rlayer);
 452     } else {
 453         s->statem.enc_write_state = ENC_WRITE_STATE_INVALID;
 454         if (s->enc_write_ctx != NULL) {
 455             EVP_CIPHER_CTX_reset(s->enc_write_ctx);
 456         } else {
 457             s->enc_write_ctx = EVP_CIPHER_CTX_new();
 458             if (s->enc_write_ctx == NULL) {
 459                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 460                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
 461                 goto err;
 462             }
 463         }
 464         ciph_ctx = s->enc_write_ctx;
 465         iv = s->write_iv;
 466
 467         RECORD_LAYER_reset_write_sequence(&s->rlayer);
 468     }
 469
 470     if (((which & SSL3_CC_CLIENT) && (which & SSL3_CC_WRITE))
 471             || ((which & SSL3_CC_SERVER) && (which & SSL3_CC_READ))) {
 472         if (which & SSL3_CC_EARLY) {
 473             EVP_MD_CTX *mdctx = NULL;
 474             long handlen;
 475             void *hdata;
 476             unsigned int hashlenui;
 477             const SSL_CIPHER *sslcipher = SSL_SESSION_get0_cipher(s->session);
 478
 479             insecret = s->early_secret;
 480             label = client_early_traffic;
 481             labellen = sizeof(client_early_traffic) - 1;
 482             log_label = CLIENT_EARLY_LABEL;
 483
 484             handlen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata);
 485             if (handlen <= 0) {
 486                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 487                          SSL_F_TLS13_CHANGE_CIPHER_STATE,
 488                          SSL_R_BAD_HANDSHAKE_LENGTH);
 489                 goto err;
 490             }
 491
 492             if (s->early_data_state == SSL_EARLY_DATA_CONNECTING
 493                     && s->max_early_data > 0
 494                     && s->session->ext.max_early_data == 0) {
 495                 /*
 496                  * If we are attempting to send early data, and we've decided to
 497                  * actually do it but max_early_data in s->session is 0 then we
 498                  * must be using an external PSK.
 499                  */
 500                 if (!ossl_assert(s->psksession != NULL
 501                         && s->max_early_data ==
 502                            s->psksession->ext.max_early_data)) {
 503                     SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 504                              SSL_F_TLS13_CHANGE_CIPHER_STATE,
 505                              ERR_R_INTERNAL_ERROR);
 506                     goto err;
 507                 }
 508                 sslcipher = SSL_SESSION_get0_cipher(s->psksession);
 509             }
 510             if (sslcipher == NULL) {
 511                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 512                          SSL_F_TLS13_CHANGE_CIPHER_STATE, SSL_R_BAD_PSK);
 513                 goto err;
 514             }
 515
 516             /*
 517              * We need to calculate the handshake digest using the digest from
 518              * the session. We haven't yet selected our ciphersuite so we can't
 519              * use ssl_handshake_md().
 520              */
 521             mdctx = EVP_MD_CTX_new();
 522             if (mdctx == NULL) {
 523                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 524                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
 525                 goto err;
 526             }
 527             cipher = EVP_get_cipherbynid(SSL_CIPHER_get_cipher_nid(sslcipher));
 528             md = ssl_md(sslcipher->algorithm2);
 529             if (md == NULL || !EVP_DigestInit_ex(mdctx, md, NULL)
 530                     || !EVP_DigestUpdate(mdctx, hdata, handlen)
 531                     || !EVP_DigestFinal_ex(mdctx, hashval, &hashlenui)) {
 532                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 533                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
 534                 EVP_MD_CTX_free(mdctx);
 535                 goto err;
 536             }
 537             hashlen = hashlenui;
 538             EVP_MD_CTX_free(mdctx);
 539
 540             if (!tls13_hkdf_expand(s, md, insecret,
 541                                    early_exporter_master_secret,
 542                                    sizeof(early_exporter_master_secret) - 1,
 543                                    hashval, hashlen,
 544                                    s->early_exporter_master_secret, hashlen,
 545                                    1)) {
 546                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 547                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
 548                 goto err;
 549             }
 550
 551             if (!ssl_log_secret(s, EARLY_EXPORTER_SECRET_LABEL,
 552                                 s->early_exporter_master_secret, hashlen)) {
 553                 /* SSLfatal() already called */
 554                 goto err;
 555             }
 556         } else if (which & SSL3_CC_HANDSHAKE) {
 557             insecret = s->handshake_secret;
 558             finsecret = s->client_finished_secret;
 559             finsecretlen = EVP_MD_size(ssl_handshake_md(s));
 560             label = client_handshake_traffic;
 561             labellen = sizeof(client_handshake_traffic) - 1;
 562             log_label = CLIENT_HANDSHAKE_LABEL;
 563             /*
 564              * The handshake hash used for the server read/client write handshake
 565              * traffic secret is the same as the hash for the server
 566              * write/client read handshake traffic secret. However, if we
 567              * processed early data then we delay changing the server
 568              * read/client write cipher state until later, and the handshake
 569              * hashes have moved on. Therefore we use the value saved earlier
 570              * when we did the server write/client read change cipher state.
 571              */
 572             hash = s->handshake_traffic_hash;
 573         } else {
 574             insecret = s->master_secret;
 575             label = client_application_traffic;
 576             labellen = sizeof(client_application_traffic) - 1;
 577             log_label = CLIENT_APPLICATION_LABEL;
 578             /*
 579              * For this we only use the handshake hashes up until the server
 580              * Finished hash. We do not include the client's Finished, which is
 581              * what ssl_handshake_hash() would give us. Instead we use the
 582              * previously saved value.
 583              */
 584             hash = s->server_finished_hash;
 585         }
 586     } else {
 587         /* Early data never applies to client-read/server-write */
 588         if (which & SSL3_CC_HANDSHAKE) {
 589             insecret = s->handshake_secret;
 590             finsecret = s->server_finished_secret;
 591             finsecretlen = EVP_MD_size(ssl_handshake_md(s));
 592             label = server_handshake_traffic;
 593             labellen = sizeof(server_handshake_traffic) - 1;
 594             log_label = SERVER_HANDSHAKE_LABEL;
 595         } else {
 596             insecret = s->master_secret;
 597             label = server_application_traffic;
 598             labellen = sizeof(server_application_traffic) - 1;
 599             log_label = SERVER_APPLICATION_LABEL;
 600         }
 601     }
 602
 603     if (!(which & SSL3_CC_EARLY)) {
 604         md = ssl_handshake_md(s);
 605         cipher = s->s3->tmp.new_sym_enc;
 606         if (!ssl3_digest_cached_records(s, 1)
 607                 || !ssl_handshake_hash(s, hashval, sizeof(hashval), &hashlen)) {
 608             /* SSLfatal() already called */;
 609             goto err;
 610         }
 611     }
 612
 613     /*
 614      * Save the hash of handshakes up to now for use when we calculate the
 615      * client application traffic secret
 616      */
 617     if (label == server_application_traffic)
 618         memcpy(s->server_finished_hash, hashval, hashlen);
 619
 620     if (label == server_handshake_traffic)
 621         memcpy(s->handshake_traffic_hash, hashval, hashlen);
 622
 623     if (label == client_application_traffic) {
 624         /*
 625          * We also create the resumption master secret, but this time use the
 626          * hash for the whole handshake including the Client Finished
 627          */
 628         if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
 629                                resumption_master_secret,
 630                                sizeof(resumption_master_secret) - 1,
 631                                hashval, hashlen, s->resumption_master_secret,
 632                                hashlen, 1)) {
 633             /* SSLfatal() already called */
 634             goto err;
 635         }
 636     }
 637
 638     if (!derive_secret_key_and_iv(s, which & SSL3_CC_WRITE, md, cipher,
 639                                   insecret, hash, label, labellen, secret, iv,
 640                                   ciph_ctx)) {
 641         /* SSLfatal() already called */
 642         goto err;
 643     }
 644
 645     if (label == server_application_traffic) {
 646         memcpy(s->server_app_traffic_secret, secret, hashlen);
 647         /* Now we create the exporter master secret */
 648         if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
 649                                exporter_master_secret,
 650                                sizeof(exporter_master_secret) - 1,
 651                                hash, hashlen, s->exporter_master_secret,
 652                                hashlen, 1)) {
 653             /* SSLfatal() already called */
 654             goto err;
 655         }
 656
 657         if (!ssl_log_secret(s, EXPORTER_SECRET_LABEL, s->exporter_master_secret,
 658                             hashlen)) {
 659             /* SSLfatal() already called */
 660             goto err;
 661         }
 662     } else if (label == client_application_traffic)
 663         memcpy(s->client_app_traffic_secret, secret, hashlen);
 664
 665     if (!ssl_log_secret(s, log_label, secret, hashlen)) {
 666         /* SSLfatal() already called */
 667         goto err;
 668     }
 669
 670     if (finsecret != NULL
 671             && !tls13_derive_finishedkey(s, ssl_handshake_md(s), secret,
 672                                          finsecret, finsecretlen)) {
 673         /* SSLfatal() already called */
 674         goto err;
 675     }
 676
 677     if (!s->server && label == client_early_traffic)
 678         s->statem.enc_write_state = ENC_WRITE_STATE_WRITE_PLAIN_ALERTS;
 679     else
 680         s->statem.enc_write_state = ENC_WRITE_STATE_VALID;
 681     ret = 1;
 682  err:
 683     OPENSSL_cleanse(secret, sizeof(secret));
 684     return ret;
 685 }
 686
 687 int tls13_update_key(SSL *s, int sending)
 688 {
 689     static const unsigned char application_traffic[] = "traffic upd";
 690     const EVP_MD *md = ssl_handshake_md(s);
 691     size_t hashlen = EVP_MD_size(md);
 692     unsigned char *insecret, *iv;
 693     unsigned char secret[EVP_MAX_MD_SIZE];
 694     EVP_CIPHER_CTX *ciph_ctx;
 695     int ret = 0;
 696
 697     if (s->server == sending)
 698         insecret = s->server_app_traffic_secret;
 699     else
 700         insecret = s->client_app_traffic_secret;
 701
 702     if (sending) {
 703         s->statem.enc_write_state = ENC_WRITE_STATE_INVALID;
 704         iv = s->write_iv;
 705         ciph_ctx = s->enc_write_ctx;
 706         RECORD_LAYER_reset_write_sequence(&s->rlayer);
 707     } else {
 708         iv = s->read_iv;
 709         ciph_ctx = s->enc_read_ctx;
 710         RECORD_LAYER_reset_read_sequence(&s->rlayer);
 711     }
 712
 713     if (!derive_secret_key_and_iv(s, sending, ssl_handshake_md(s),
 714                                   s->s3->tmp.new_sym_enc, insecret, NULL,
 715                                   application_traffic,
 716                                   sizeof(application_traffic) - 1, secret, iv,
 717                                   ciph_ctx)) {
 718         /* SSLfatal() already called */
 719         goto err;
 720     }
 721
 722     memcpy(insecret, secret, hashlen);
 723
 724     s->statem.enc_write_state = ENC_WRITE_STATE_VALID;
 725     ret = 1;
 726  err:
 727     OPENSSL_cleanse(secret, sizeof(secret));
 728     return ret;
 729 }
 730
 731 int tls13_alert_code(int code)
 732 {
 733     /* There are 2 additional alerts in TLSv1.3 compared to TLSv1.2 */
 734     if (code == SSL_AD_MISSING_EXTENSION || code == SSL_AD_CERTIFICATE_REQUIRED)
 735         return code;
 736
 737     return tls1_alert_code(code);
 738 }
 739
 740 int tls13_export_keying_material(SSL *s, unsigned char *out, size_t olen,
 741                                  const char *label, size_t llen,
 742                                  const unsigned char *context,
 743                                  size_t contextlen, int use_context)
 744 {
 745     unsigned char exportsecret[EVP_MAX_MD_SIZE];
 746     static const unsigned char exporterlabel[] = "exporter";
 747     unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE];
 748     const EVP_MD *md = ssl_handshake_md(s);
 749     EVP_MD_CTX *ctx = EVP_MD_CTX_new();
 750     unsigned int hashsize, datalen;
 751     int ret = 0;
 752
 753     if (ctx == NULL || !ossl_statem_export_allowed(s))
 754         goto err;
 755
 756     if (!use_context)
 757         contextlen = 0;
 758
 759     if (EVP_DigestInit_ex(ctx, md, NULL) <= 0
 760             || EVP_DigestUpdate(ctx, context, contextlen) <= 0
 761             || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0
 762             || EVP_DigestInit_ex(ctx, md, NULL) <= 0
 763             || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0
 764             || !tls13_hkdf_expand(s, md, s->exporter_master_secret,
 765                                   (const unsigned char *)label, llen,
 766                                   data, datalen, exportsecret, hashsize, 0)
 767             || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel,
 768                                   sizeof(exporterlabel) - 1, hash, hashsize,
 769                                   out, olen, 0))
 770         goto err;
 771
 772     ret = 1;
 773  err:
 774     EVP_MD_CTX_free(ctx);
 775     return ret;
 776 }
 777
 778 int tls13_export_keying_material_early(SSL *s, unsigned char *out, size_t olen,
 779                                        const char *label, size_t llen,
 780                                        const unsigned char *context,
 781                                        size_t contextlen)
 782 {
 783     static const unsigned char exporterlabel[] = "exporter";
 784     unsigned char exportsecret[EVP_MAX_MD_SIZE];
 785     unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE];
 786     const EVP_MD *md;
 787     EVP_MD_CTX *ctx = EVP_MD_CTX_new();
 788     unsigned int hashsize, datalen;
 789     int ret = 0;
 790     const SSL_CIPHER *sslcipher;
 791
 792     if (ctx == NULL || !ossl_statem_export_early_allowed(s))
 793         goto err;
 794
 795     if (!s->server && s->max_early_data > 0
 796             && s->session->ext.max_early_data == 0)
 797         sslcipher = SSL_SESSION_get0_cipher(s->psksession);
 798     else
 799         sslcipher = SSL_SESSION_get0_cipher(s->session);
 800
 801     md = ssl_md(sslcipher->algorithm2);
 802
 803     /*
 804      * Calculate the hash value and store it in |data|. The reason why
 805      * the empty string is used is that the definition of TLS-Exporter
 806      * is like so:
 807      *
 808      * TLS-Exporter(label, context_value, key_length) =
 809      *     HKDF-Expand-Label(Derive-Secret(Secret, label, ""),
 810      *                       "exporter", Hash(context_value), key_length)
 811      *
 812      * Derive-Secret(Secret, Label, Messages) =
 813      *       HKDF-Expand-Label(Secret, Label,
 814      *                         Transcript-Hash(Messages), Hash.length)
 815      *
 816      * Here Transcript-Hash is the cipher suite hash algorithm.
 817      */
 818     if (EVP_DigestInit_ex(ctx, md, NULL) <= 0
 819             || EVP_DigestUpdate(ctx, context, contextlen) <= 0
 820             || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0
 821             || EVP_DigestInit_ex(ctx, md, NULL) <= 0
 822             || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0
 823             || !tls13_hkdf_expand(s, md, s->early_exporter_master_secret,
 824                                   (const unsigned char *)label, llen,
 825                                   data, datalen, exportsecret, hashsize, 0)
 826             || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel,
 827                                   sizeof(exporterlabel) - 1, hash, hashsize,
 828                                   out, olen, 0))
 829         goto err;
 830
 831     ret = 1;
 832  err:
 833     EVP_MD_CTX_free(ctx);
 834     return ret;
 835 }