ssl/tls13_enc.c

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