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