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_local.h"
  12 #include "internal/cryptlib.h"
  13 #include <openssl/evp.h>
  14 #include <openssl/kdf.h>
  15 #include <openssl/core_names.h>
  16
  17 #define TLS13_MAX_LABEL_LEN     249
  18
  19 /* Always filled with zeros */
  20 static const unsigned char default_zeros[EVP_MAX_MD_SIZE];
  21
  22 /*
  23  * Given a |secret|; a |label| of length |labellen|; and |data| of length
  24  * |datalen| (e.g. typically a hash of the handshake messages), derive a new
  25  * secret |outlen| bytes long and store it in the location pointed to be |out|.
  26  * The |data| value may be zero length. Any errors will be treated as fatal if
  27  * |fatal| is set. Returns 1 on success  0 on failure.
  28  */
  29 int tls13_hkdf_expand(SSL *s, const EVP_MD *md, const unsigned char *secret,
  30                              const unsigned char *label, size_t labellen,
  31                              const unsigned char *data, size_t datalen,
  32                              unsigned char *out, size_t outlen, int fatal)
  33 {
  34 #ifdef CHARSET_EBCDIC
  35     static const unsigned char label_prefix[] = { 0x74, 0x6C, 0x73, 0x31, 0x33, 0x20, 0x00 };
  36 #else
  37     static const unsigned char label_prefix[] = "tls13 ";
  38 #endif
  39     EVP_KDF *kdf = EVP_KDF_fetch(NULL, OSSL_KDF_NAME_HKDF, NULL);
  40     EVP_KDF_CTX *kctx;
  41     OSSL_PARAM params[5], *p = params;
  42     int mode = EVP_PKEY_HKDEF_MODE_EXPAND_ONLY;
  43     const char *mdname = EVP_MD_name(md);
  44     int ret;
  45     size_t hkdflabellen;
  46     size_t hashlen;
  47     /*
  48      * 2 bytes for length of derived secret + 1 byte for length of combined
  49      * prefix and label + bytes for the label itself + 1 byte length of hash
  50      * + bytes for the hash itself
  51      */
  52     unsigned char hkdflabel[sizeof(uint16_t) + sizeof(uint8_t)
  53                             + (sizeof(label_prefix) - 1) + TLS13_MAX_LABEL_LEN
  54                             + 1 + EVP_MAX_MD_SIZE];
  55     WPACKET pkt;
  56
  57     kctx = EVP_KDF_CTX_new(kdf);
  58     EVP_KDF_free(kdf);
  59     if (kctx == NULL)
  60         return 0;
  61
  62     if (labellen > TLS13_MAX_LABEL_LEN) {
  63         if (fatal) {
  64             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
  65                      ERR_R_INTERNAL_ERROR);
  66         } else {
  67             /*
  68              * Probably we have been called from SSL_export_keying_material(),
  69              * or SSL_export_keying_material_early().
  70              */
  71             SSLerr(SSL_F_TLS13_HKDF_EXPAND, SSL_R_TLS_ILLEGAL_EXPORTER_LABEL);
  72         }
  73         EVP_KDF_CTX_free(kctx);
  74         return 0;
  75     }
  76
  77     hashlen = EVP_MD_size(md);
  78
  79     if (!WPACKET_init_static_len(&pkt, hkdflabel, sizeof(hkdflabel), 0)
  80             || !WPACKET_put_bytes_u16(&pkt, outlen)
  81             || !WPACKET_start_sub_packet_u8(&pkt)
  82             || !WPACKET_memcpy(&pkt, label_prefix, sizeof(label_prefix) - 1)
  83             || !WPACKET_memcpy(&pkt, label, labellen)
  84             || !WPACKET_close(&pkt)
  85             || !WPACKET_sub_memcpy_u8(&pkt, data, (data == NULL) ? 0 : datalen)
  86             || !WPACKET_get_total_written(&pkt, &hkdflabellen)
  87             || !WPACKET_finish(&pkt)) {
  88         EVP_KDF_CTX_free(kctx);
  89         WPACKET_cleanup(&pkt);
  90         if (fatal)
  91             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
  92                      ERR_R_INTERNAL_ERROR);
  93         else
  94             SSLerr(SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR);
  95         return 0;
  96     }
  97
  98     *p++ = OSSL_PARAM_construct_int(OSSL_KDF_PARAM_MODE, &mode);
  99     *p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
 100                                             (char *)mdname, 0);
 101     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY,
 102                                              (unsigned char *)secret, hashlen);
 103     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_INFO,
 104                                              hkdflabel, hkdflabellen);
 105     *p++ = OSSL_PARAM_construct_end();
 106
 107     ret = EVP_KDF_CTX_set_params(kctx, params) <= 0
 108         || EVP_KDF_derive(kctx, out, outlen) <= 0;
 109
 110     EVP_KDF_CTX_free(kctx);
 111
 112     if (ret != 0) {
 113         if (fatal)
 114             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
 115                      ERR_R_INTERNAL_ERROR);
 116         else
 117             SSLerr(SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR);
 118     }
 119
 120     return ret == 0;
 121 }
 122
 123 /*
 124  * Given a |secret| generate a |key| of length |keylen| bytes. Returns 1 on
 125  * success  0 on failure.
 126  */
 127 int tls13_derive_key(SSL *s, const EVP_MD *md, const unsigned char *secret,
 128                      unsigned char *key, size_t keylen)
 129 {
 130 #ifdef CHARSET_EBCDIC
 131   static const unsigned char keylabel[] ={ 0x6B, 0x65, 0x79, 0x00 };
 132 #else
 133   static const unsigned char keylabel[] = "key";
 134 #endif
 135
 136     return tls13_hkdf_expand(s, md, secret, keylabel, sizeof(keylabel) - 1,
 137                              NULL, 0, key, keylen, 1);
 138 }
 139
 140 /*
 141  * Given a |secret| generate an |iv| of length |ivlen| bytes. Returns 1 on
 142  * success  0 on failure.
 143  */
 144 int tls13_derive_iv(SSL *s, const EVP_MD *md, const unsigned char *secret,
 145                     unsigned char *iv, size_t ivlen)
 146 {
 147 #ifdef CHARSET_EBCDIC
 148   static const unsigned char ivlabel[] = { 0x69, 0x76, 0x00 };
 149 #else
 150   static const unsigned char ivlabel[] = "iv";
 151 #endif
 152
 153     return tls13_hkdf_expand(s, md, secret, ivlabel, sizeof(ivlabel) - 1,
 154                              NULL, 0, iv, ivlen, 1);
 155 }
 156
 157 int tls13_derive_finishedkey(SSL *s, const EVP_MD *md,
 158                              const unsigned char *secret,
 159                              unsigned char *fin, size_t finlen)
 160 {
 161 #ifdef CHARSET_EBCDIC
 162   static const unsigned char finishedlabel[] = { 0x66, 0x69, 0x6E, 0x69, 0x73, 0x68, 0x65, 0x64, 0x00 };
 163 #else
 164   static const unsigned char finishedlabel[] = "finished";
 165 #endif
 166
 167     return tls13_hkdf_expand(s, md, secret, finishedlabel,
 168                              sizeof(finishedlabel) - 1, NULL, 0, fin, finlen, 1);
 169 }
 170
 171 /*
 172  * Given the previous secret |prevsecret| and a new input secret |insecret| of
 173  * length |insecretlen|, generate a new secret and store it in the location
 174  * pointed to by |outsecret|. Returns 1 on success  0 on failure.
 175  */
 176 int tls13_generate_secret(SSL *s, const EVP_MD *md,
 177                           const unsigned char *prevsecret,
 178                           const unsigned char *insecret,
 179                           size_t insecretlen,
 180                           unsigned char *outsecret)
 181 {
 182     size_t mdlen, prevsecretlen;
 183     int mdleni;
 184     int ret;
 185     EVP_KDF *kdf;
 186     EVP_KDF_CTX *kctx;
 187     OSSL_PARAM params[5], *p = params;
 188     int mode = EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY;
 189     const char *mdname = EVP_MD_name(md);
 190 #ifdef CHARSET_EBCDIC
 191     static const char derived_secret_label[] = { 0x64, 0x65, 0x72, 0x69, 0x76, 0x65, 0x64, 0x00 };
 192 #else
 193     static const char derived_secret_label[] = "derived";
 194 #endif
 195     unsigned char preextractsec[EVP_MAX_MD_SIZE];
 196
 197     kdf = EVP_KDF_fetch(NULL, OSSL_KDF_NAME_HKDF, NULL);
 198     kctx = EVP_KDF_CTX_new(kdf);
 199     EVP_KDF_free(kdf);
 200     if (kctx == NULL) {
 201         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
 202                  ERR_R_INTERNAL_ERROR);
 203         return 0;
 204     }
 205
 206     mdleni = EVP_MD_size(md);
 207     /* Ensure cast to size_t is safe */
 208     if (!ossl_assert(mdleni >= 0)) {
 209         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
 210                  ERR_R_INTERNAL_ERROR);
 211         EVP_KDF_CTX_free(kctx);
 212         return 0;
 213     }
 214     mdlen = (size_t)mdleni;
 215
 216     if (insecret == NULL) {
 217         insecret = default_zeros;
 218         insecretlen = mdlen;
 219     }
 220     if (prevsecret == NULL) {
 221         prevsecret = default_zeros;
 222         prevsecretlen = 0;
 223     } else {
 224         EVP_MD_CTX *mctx = EVP_MD_CTX_new();
 225         unsigned char hash[EVP_MAX_MD_SIZE];
 226
 227         /* The pre-extract derive step uses a hash of no messages */
 228         if (mctx == NULL
 229                 || EVP_DigestInit_ex(mctx, md, NULL) <= 0
 230                 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
 231             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
 232                      ERR_R_INTERNAL_ERROR);
 233             EVP_MD_CTX_free(mctx);
 234             EVP_KDF_CTX_free(kctx);
 235             return 0;
 236         }
 237         EVP_MD_CTX_free(mctx);
 238
 239         /* Generate the pre-extract secret */
 240         if (!tls13_hkdf_expand(s, md, prevsecret,
 241                                (unsigned char *)derived_secret_label,
 242                                sizeof(derived_secret_label) - 1, hash, mdlen,
 243                                preextractsec, mdlen, 1)) {
 244             /* SSLfatal() already called */
 245             EVP_KDF_CTX_free(kctx);
 246             return 0;
 247         }
 248
 249         prevsecret = preextractsec;
 250         prevsecretlen = mdlen;
 251     }
 252
 253     *p++ = OSSL_PARAM_construct_int(OSSL_KDF_PARAM_MODE, &mode);
 254     *p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
 255                                             (char *)mdname, 0);
 256     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY,
 257                                              (unsigned char *)insecret,
 258                                              insecretlen);
 259     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SALT,
 260                                              (unsigned char *)prevsecret,
 261                                              prevsecretlen);
 262     *p++ = OSSL_PARAM_construct_end();
 263
 264     ret = EVP_KDF_CTX_set_params(kctx, params) <= 0
 265         || EVP_KDF_derive(kctx, outsecret, mdlen) <= 0;
 266
 267     if (ret != 0)
 268         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
 269                  ERR_R_INTERNAL_ERROR);
 270
 271     EVP_KDF_CTX_free(kctx);
 272     if (prevsecret == preextractsec)
 273         OPENSSL_cleanse(preextractsec, mdlen);
 274     return ret == 0;
 275 }
 276
 277 /*
 278  * Given an input secret |insecret| of length |insecretlen| generate the
 279  * handshake secret. This requires the early secret to already have been
 280  * generated. Returns 1 on success  0 on failure.
 281  */
 282 int tls13_generate_handshake_secret(SSL *s, const unsigned char *insecret,
 283                                 size_t insecretlen)
 284 {
 285     /* Calls SSLfatal() if required */
 286     return tls13_generate_secret(s, ssl_handshake_md(s), s->early_secret,
 287                                  insecret, insecretlen,
 288                                  (unsigned char *)&s->handshake_secret);
 289 }
 290
 291 /*
 292  * Given the handshake secret |prev| of length |prevlen| generate the master
 293  * secret and store its length in |*secret_size|. Returns 1 on success  0 on
 294  * failure.
 295  */
 296 int tls13_generate_master_secret(SSL *s, unsigned char *out,
 297                                  unsigned char *prev, size_t prevlen,
 298                                  size_t *secret_size)
 299 {
 300     const EVP_MD *md = ssl_handshake_md(s);
 301
 302     *secret_size = EVP_MD_size(md);
 303     /* Calls SSLfatal() if required */
 304     return tls13_generate_secret(s, md, prev, NULL, 0, out);
 305 }
 306
 307 /*
 308  * Generates the mac for the Finished message. Returns the length of the MAC or
 309  * 0 on error.
 310  */
 311 size_t tls13_final_finish_mac(SSL *s, const char *str, size_t slen,
 312                              unsigned char *out)
 313 {
 314     const EVP_MD *md = ssl_handshake_md(s);
 315     unsigned char hash[EVP_MAX_MD_SIZE];
 316     size_t hashlen, ret = 0;
 317     EVP_PKEY *key = NULL;
 318     EVP_MD_CTX *ctx = EVP_MD_CTX_new();
 319
 320     if (!ssl_handshake_hash(s, hash, sizeof(hash), &hashlen)) {
 321         /* SSLfatal() already called */
 322         goto err;
 323     }
 324
 325     if (str == s->method->ssl3_enc->server_finished_label) {
 326         key = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL,
 327                                            s->server_finished_secret, hashlen);
 328     } else if (SSL_IS_FIRST_HANDSHAKE(s)) {
 329         key = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL,
 330                                            s->client_finished_secret, hashlen);
 331     } else {
 332         unsigned char finsecret[EVP_MAX_MD_SIZE];
 333
 334         if (!tls13_derive_finishedkey(s, ssl_handshake_md(s),
 335                                       s->client_app_traffic_secret,
 336                                       finsecret, hashlen))
 337             goto err;
 338
 339         key = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL, finsecret,
 340                                            hashlen);
 341         OPENSSL_cleanse(finsecret, sizeof(finsecret));
 342     }
 343
 344     if (key == NULL
 345             || ctx == NULL
 346             || EVP_DigestSignInit(ctx, NULL, md, NULL, key) <= 0
 347             || EVP_DigestSignUpdate(ctx, hash, hashlen) <= 0
 348             || EVP_DigestSignFinal(ctx, out, &hashlen) <= 0) {
 349         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_FINAL_FINISH_MAC,
 350                  ERR_R_INTERNAL_ERROR);
 351         goto err;
 352     }
 353
 354     ret = hashlen;
 355  err:
 356     EVP_PKEY_free(key);
 357     EVP_MD_CTX_free(ctx);
 358     return ret;
 359 }
 360
 361 /*
 362  * There isn't really a key block in TLSv1.3, but we still need this function
 363  * for initialising the cipher and hash. Returns 1 on success or 0 on failure.
 364  */
 365 int tls13_setup_key_block(SSL *s)
 366 {
 367     const EVP_CIPHER *c;
 368     const EVP_MD *hash;
 369
 370     s->session->cipher = s->s3.tmp.new_cipher;
 371     if (!ssl_cipher_get_evp(s->session, &c, &hash, NULL, NULL, NULL, 0)) {
 372         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_SETUP_KEY_BLOCK,
 373                  SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
 374         return 0;
 375     }
 376
 377     s->s3.tmp.new_sym_enc = c;
 378     s->s3.tmp.new_hash = hash;
 379
 380     return 1;
 381 }
 382
 383 static int derive_secret_key_and_iv(SSL *s, int sending, const EVP_MD *md,
 384                                     const EVP_CIPHER *ciph,
 385                                     const unsigned char *insecret,
 386                                     const unsigned char *hash,
 387                                     const unsigned char *label,
 388                                     size_t labellen, unsigned char *secret,
 389                                     unsigned char *iv, EVP_CIPHER_CTX *ciph_ctx)
 390 {
 391     unsigned char key[EVP_MAX_KEY_LENGTH];
 392     size_t ivlen, keylen, taglen;
 393     int hashleni = EVP_MD_size(md);
 394     size_t hashlen;
 395
 396     /* Ensure cast to size_t is safe */
 397     if (!ossl_assert(hashleni >= 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     hashlen = (size_t)hashleni;
 403
 404     if (!tls13_hkdf_expand(s, md, insecret, label, labellen, hash, hashlen,
 405                            secret, hashlen, 1)) {
 406         /* SSLfatal() already called */
 407         goto err;
 408     }
 409
 410     /* TODO(size_t): convert me */
 411     keylen = EVP_CIPHER_key_length(ciph);
 412     if (EVP_CIPHER_mode(ciph) == EVP_CIPH_CCM_MODE) {
 413         uint32_t algenc;
 414
 415         ivlen = EVP_CCM_TLS_IV_LEN;
 416         if (s->s3.tmp.new_cipher == NULL) {
 417             /* We've not selected a cipher yet - we must be doing early data */
 418             algenc = s->session->cipher->algorithm_enc;
 419         } else {
 420             algenc = s->s3.tmp.new_cipher->algorithm_enc;
 421         }
 422         if (algenc & (SSL_AES128CCM8 | SSL_AES256CCM8))
 423             taglen = EVP_CCM8_TLS_TAG_LEN;
 424          else
 425             taglen = EVP_CCM_TLS_TAG_LEN;
 426     } else {
 427         ivlen = EVP_CIPHER_iv_length(ciph);
 428         taglen = 0;
 429     }
 430
 431     if (!tls13_derive_key(s, md, secret, key, keylen)
 432             || !tls13_derive_iv(s, md, secret, iv, ivlen)) {
 433         /* SSLfatal() already called */
 434         goto err;
 435     }
 436
 437     if (EVP_CipherInit_ex(ciph_ctx, ciph, NULL, NULL, NULL, sending) <= 0
 438         || !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
 439         || (taglen != 0 && !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_TAG,
 440                                                 taglen, NULL))
 441         || EVP_CipherInit_ex(ciph_ctx, NULL, NULL, key, NULL, -1) <= 0) {
 442         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DERIVE_SECRET_KEY_AND_IV,
 443                  ERR_R_EVP_LIB);
 444         goto err;
 445     }
 446
 447     return 1;
 448  err:
 449     OPENSSL_cleanse(key, sizeof(key));
 450     return 0;
 451 }
 452
 453 int tls13_change_cipher_state(SSL *s, int which)
 454 {
 455 #ifdef CHARSET_EBCDIC
 456   static const unsigned char client_early_traffic[]       = {0x63, 0x20, 0x65, 0x20,       /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
 457   static const unsigned char client_handshake_traffic[]   = {0x63, 0x20, 0x68, 0x73, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
 458   static const unsigned char client_application_traffic[] = {0x63, 0x20, 0x61, 0x70, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
 459   static const unsigned char server_handshake_traffic[]   = {0x73, 0x20, 0x68, 0x73, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
 460   static const unsigned char server_application_traffic[] = {0x73, 0x20, 0x61, 0x70, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
 461   static const unsigned char exporter_master_secret[] = {0x65, 0x78, 0x70, 0x20,                    /* master*/  0x6D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x00};
 462   static const unsigned char resumption_master_secret[] = {0x72, 0x65, 0x73, 0x20,                  /* master*/  0x6D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x00};
 463   static const unsigned char early_exporter_master_secret[] = {0x65, 0x20, 0x65, 0x78, 0x70, 0x20,  /* master*/  0x6D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x00};
 464 #else
 465     static const unsigned char client_early_traffic[] = "c e traffic";
 466     static const unsigned char client_handshake_traffic[] = "c hs traffic";
 467     static const unsigned char client_application_traffic[] = "c ap traffic";
 468     static const unsigned char server_handshake_traffic[] = "s hs traffic";
 469     static const unsigned char server_application_traffic[] = "s ap traffic";
 470     static const unsigned char exporter_master_secret[] = "exp master";
 471     static const unsigned char resumption_master_secret[] = "res master";
 472     static const unsigned char early_exporter_master_secret[] = "e exp master";
 473 #endif
 474     unsigned char *iv;
 475     unsigned char secret[EVP_MAX_MD_SIZE];
 476     unsigned char hashval[EVP_MAX_MD_SIZE];
 477     unsigned char *hash = hashval;
 478     unsigned char *insecret;
 479     unsigned char *finsecret = NULL;
 480     const char *log_label = NULL;
 481     EVP_CIPHER_CTX *ciph_ctx;
 482     size_t finsecretlen = 0;
 483     const unsigned char *label;
 484     size_t labellen, hashlen = 0;
 485     int ret = 0;
 486     const EVP_MD *md = NULL;
 487     const EVP_CIPHER *cipher = NULL;
 488
 489     if (which & SSL3_CC_READ) {
 490         if (s->enc_read_ctx != NULL) {
 491             EVP_CIPHER_CTX_reset(s->enc_read_ctx);
 492         } else {
 493             s->enc_read_ctx = EVP_CIPHER_CTX_new();
 494             if (s->enc_read_ctx == NULL) {
 495                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 496                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
 497                 goto err;
 498             }
 499         }
 500         ciph_ctx = s->enc_read_ctx;
 501         iv = s->read_iv;
 502
 503         RECORD_LAYER_reset_read_sequence(&s->rlayer);
 504     } else {
 505         s->statem.enc_write_state = ENC_WRITE_STATE_INVALID;
 506         if (s->enc_write_ctx != NULL) {
 507             EVP_CIPHER_CTX_reset(s->enc_write_ctx);
 508         } else {
 509             s->enc_write_ctx = EVP_CIPHER_CTX_new();
 510             if (s->enc_write_ctx == NULL) {
 511                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 512                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
 513                 goto err;
 514             }
 515         }
 516         ciph_ctx = s->enc_write_ctx;
 517         iv = s->write_iv;
 518
 519         RECORD_LAYER_reset_write_sequence(&s->rlayer);
 520     }
 521
 522     if (((which & SSL3_CC_CLIENT) && (which & SSL3_CC_WRITE))
 523             || ((which & SSL3_CC_SERVER) && (which & SSL3_CC_READ))) {
 524         if (which & SSL3_CC_EARLY) {
 525             EVP_MD_CTX *mdctx = NULL;
 526             long handlen;
 527             void *hdata;
 528             unsigned int hashlenui;
 529             const SSL_CIPHER *sslcipher = SSL_SESSION_get0_cipher(s->session);
 530
 531             insecret = s->early_secret;
 532             label = client_early_traffic;
 533             labellen = sizeof(client_early_traffic) - 1;
 534             log_label = CLIENT_EARLY_LABEL;
 535
 536             handlen = BIO_get_mem_data(s->s3.handshake_buffer, &hdata);
 537             if (handlen <= 0) {
 538                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 539                          SSL_F_TLS13_CHANGE_CIPHER_STATE,
 540                          SSL_R_BAD_HANDSHAKE_LENGTH);
 541                 goto err;
 542             }
 543
 544             if (s->early_data_state == SSL_EARLY_DATA_CONNECTING
 545                     && s->max_early_data > 0
 546                     && s->session->ext.max_early_data == 0) {
 547                 /*
 548                  * If we are attempting to send early data, and we've decided to
 549                  * actually do it but max_early_data in s->session is 0 then we
 550                  * must be using an external PSK.
 551                  */
 552                 if (!ossl_assert(s->psksession != NULL
 553                         && s->max_early_data ==
 554                            s->psksession->ext.max_early_data)) {
 555                     SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 556                              SSL_F_TLS13_CHANGE_CIPHER_STATE,
 557                              ERR_R_INTERNAL_ERROR);
 558                     goto err;
 559                 }
 560                 sslcipher = SSL_SESSION_get0_cipher(s->psksession);
 561             }
 562             if (sslcipher == NULL) {
 563                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 564                          SSL_F_TLS13_CHANGE_CIPHER_STATE, SSL_R_BAD_PSK);
 565                 goto err;
 566             }
 567
 568             /*
 569              * We need to calculate the handshake digest using the digest from
 570              * the session. We haven't yet selected our ciphersuite so we can't
 571              * use ssl_handshake_md().
 572              */
 573             mdctx = EVP_MD_CTX_new();
 574             if (mdctx == NULL) {
 575                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 576                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
 577                 goto err;
 578             }
 579             cipher = EVP_get_cipherbynid(SSL_CIPHER_get_cipher_nid(sslcipher));
 580             md = ssl_md(sslcipher->algorithm2);
 581             if (md == NULL || !EVP_DigestInit_ex(mdctx, md, NULL)
 582                     || !EVP_DigestUpdate(mdctx, hdata, handlen)
 583                     || !EVP_DigestFinal_ex(mdctx, hashval, &hashlenui)) {
 584                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 585                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
 586                 EVP_MD_CTX_free(mdctx);
 587                 goto err;
 588             }
 589             hashlen = hashlenui;
 590             EVP_MD_CTX_free(mdctx);
 591
 592             if (!tls13_hkdf_expand(s, md, insecret,
 593                                    early_exporter_master_secret,
 594                                    sizeof(early_exporter_master_secret) - 1,
 595                                    hashval, hashlen,
 596                                    s->early_exporter_master_secret, hashlen,
 597                                    1)) {
 598                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 599                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
 600                 goto err;
 601             }
 602
 603             if (!ssl_log_secret(s, EARLY_EXPORTER_SECRET_LABEL,
 604                                 s->early_exporter_master_secret, hashlen)) {
 605                 /* SSLfatal() already called */
 606                 goto err;
 607             }
 608         } else if (which & SSL3_CC_HANDSHAKE) {
 609             insecret = s->handshake_secret;
 610             finsecret = s->client_finished_secret;
 611             finsecretlen = EVP_MD_size(ssl_handshake_md(s));
 612             label = client_handshake_traffic;
 613             labellen = sizeof(client_handshake_traffic) - 1;
 614             log_label = CLIENT_HANDSHAKE_LABEL;
 615             /*
 616              * The handshake hash used for the server read/client write handshake
 617              * traffic secret is the same as the hash for the server
 618              * write/client read handshake traffic secret. However, if we
 619              * processed early data then we delay changing the server
 620              * read/client write cipher state until later, and the handshake
 621              * hashes have moved on. Therefore we use the value saved earlier
 622              * when we did the server write/client read change cipher state.
 623              */
 624             hash = s->handshake_traffic_hash;
 625         } else {
 626             insecret = s->master_secret;
 627             label = client_application_traffic;
 628             labellen = sizeof(client_application_traffic) - 1;
 629             log_label = CLIENT_APPLICATION_LABEL;
 630             /*
 631              * For this we only use the handshake hashes up until the server
 632              * Finished hash. We do not include the client's Finished, which is
 633              * what ssl_handshake_hash() would give us. Instead we use the
 634              * previously saved value.
 635              */
 636             hash = s->server_finished_hash;
 637         }
 638     } else {
 639         /* Early data never applies to client-read/server-write */
 640         if (which & SSL3_CC_HANDSHAKE) {
 641             insecret = s->handshake_secret;
 642             finsecret = s->server_finished_secret;
 643             finsecretlen = EVP_MD_size(ssl_handshake_md(s));
 644             label = server_handshake_traffic;
 645             labellen = sizeof(server_handshake_traffic) - 1;
 646             log_label = SERVER_HANDSHAKE_LABEL;
 647         } else {
 648             insecret = s->master_secret;
 649             label = server_application_traffic;
 650             labellen = sizeof(server_application_traffic) - 1;
 651             log_label = SERVER_APPLICATION_LABEL;
 652         }
 653     }
 654
 655     if (!(which & SSL3_CC_EARLY)) {
 656         md = ssl_handshake_md(s);
 657         cipher = s->s3.tmp.new_sym_enc;
 658         if (!ssl3_digest_cached_records(s, 1)
 659                 || !ssl_handshake_hash(s, hashval, sizeof(hashval), &hashlen)) {
 660             /* SSLfatal() already called */;
 661             goto err;
 662         }
 663     }
 664
 665     /*
 666      * Save the hash of handshakes up to now for use when we calculate the
 667      * client application traffic secret
 668      */
 669     if (label == server_application_traffic)
 670         memcpy(s->server_finished_hash, hashval, hashlen);
 671
 672     if (label == server_handshake_traffic)
 673         memcpy(s->handshake_traffic_hash, hashval, hashlen);
 674
 675     if (label == client_application_traffic) {
 676         /*
 677          * We also create the resumption master secret, but this time use the
 678          * hash for the whole handshake including the Client Finished
 679          */
 680         if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
 681                                resumption_master_secret,
 682                                sizeof(resumption_master_secret) - 1,
 683                                hashval, hashlen, s->resumption_master_secret,
 684                                hashlen, 1)) {
 685             /* SSLfatal() already called */
 686             goto err;
 687         }
 688     }
 689
 690     if (!derive_secret_key_and_iv(s, which & SSL3_CC_WRITE, md, cipher,
 691                                   insecret, hash, label, labellen, secret, iv,
 692                                   ciph_ctx)) {
 693         /* SSLfatal() already called */
 694         goto err;
 695     }
 696
 697     if (label == server_application_traffic) {
 698         memcpy(s->server_app_traffic_secret, secret, hashlen);
 699         /* Now we create the exporter master secret */
 700         if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
 701                                exporter_master_secret,
 702                                sizeof(exporter_master_secret) - 1,
 703                                hash, hashlen, s->exporter_master_secret,
 704                                hashlen, 1)) {
 705             /* SSLfatal() already called */
 706             goto err;
 707         }
 708
 709         if (!ssl_log_secret(s, EXPORTER_SECRET_LABEL, s->exporter_master_secret,
 710                             hashlen)) {
 711             /* SSLfatal() already called */
 712             goto err;
 713         }
 714     } else if (label == client_application_traffic)
 715         memcpy(s->client_app_traffic_secret, secret, hashlen);
 716
 717     if (!ssl_log_secret(s, log_label, secret, hashlen)) {
 718         /* SSLfatal() already called */
 719         goto err;
 720     }
 721
 722     if (finsecret != NULL
 723             && !tls13_derive_finishedkey(s, ssl_handshake_md(s), secret,
 724                                          finsecret, finsecretlen)) {
 725         /* SSLfatal() already called */
 726         goto err;
 727     }
 728
 729     if (!s->server && label == client_early_traffic)
 730         s->statem.enc_write_state = ENC_WRITE_STATE_WRITE_PLAIN_ALERTS;
 731     else
 732         s->statem.enc_write_state = ENC_WRITE_STATE_VALID;
 733     ret = 1;
 734  err:
 735     OPENSSL_cleanse(secret, sizeof(secret));
 736     return ret;
 737 }
 738
 739 int tls13_update_key(SSL *s, int sending)
 740 {
 741 #ifdef CHARSET_EBCDIC
 742   static const unsigned char application_traffic[] = { 0x74, 0x72 ,0x61 ,0x66 ,0x66 ,0x69 ,0x63 ,0x20 ,0x75 ,0x70 ,0x64, 0x00};
 743 #else
 744   static const unsigned char application_traffic[] = "traffic upd";
 745 #endif
 746     const EVP_MD *md = ssl_handshake_md(s);
 747     size_t hashlen = EVP_MD_size(md);
 748     unsigned char *insecret, *iv;
 749     unsigned char secret[EVP_MAX_MD_SIZE];
 750     EVP_CIPHER_CTX *ciph_ctx;
 751     int ret = 0;
 752
 753     if (s->server == sending)
 754         insecret = s->server_app_traffic_secret;
 755     else
 756         insecret = s->client_app_traffic_secret;
 757
 758     if (sending) {
 759         s->statem.enc_write_state = ENC_WRITE_STATE_INVALID;
 760         iv = s->write_iv;
 761         ciph_ctx = s->enc_write_ctx;
 762         RECORD_LAYER_reset_write_sequence(&s->rlayer);
 763     } else {
 764         iv = s->read_iv;
 765         ciph_ctx = s->enc_read_ctx;
 766         RECORD_LAYER_reset_read_sequence(&s->rlayer);
 767     }
 768
 769     if (!derive_secret_key_and_iv(s, sending, ssl_handshake_md(s),
 770                                   s->s3.tmp.new_sym_enc, insecret, NULL,
 771                                   application_traffic,
 772                                   sizeof(application_traffic) - 1, secret, iv,
 773                                   ciph_ctx)) {
 774         /* SSLfatal() already called */
 775         goto err;
 776     }
 777
 778     memcpy(insecret, secret, hashlen);
 779
 780     s->statem.enc_write_state = ENC_WRITE_STATE_VALID;
 781     ret = 1;
 782  err:
 783     OPENSSL_cleanse(secret, sizeof(secret));
 784     return ret;
 785 }
 786
 787 int tls13_alert_code(int code)
 788 {
 789     /* There are 2 additional alerts in TLSv1.3 compared to TLSv1.2 */
 790     if (code == SSL_AD_MISSING_EXTENSION || code == SSL_AD_CERTIFICATE_REQUIRED)
 791         return code;
 792
 793     return tls1_alert_code(code);
 794 }
 795
 796 int tls13_export_keying_material(SSL *s, unsigned char *out, size_t olen,
 797                                  const char *label, size_t llen,
 798                                  const unsigned char *context,
 799                                  size_t contextlen, int use_context)
 800 {
 801     unsigned char exportsecret[EVP_MAX_MD_SIZE];
 802 #ifdef CHARSET_EBCDIC
 803     static const unsigned char exporterlabel[] = {0x65, 0x78, 0x70, 0x6F, 0x72, 0x74, 0x65, 0x72, 0x00};
 804 #else
 805     static const unsigned char exporterlabel[] = "exporter";
 806 #endif
 807     unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE];
 808     const EVP_MD *md = ssl_handshake_md(s);
 809     EVP_MD_CTX *ctx = EVP_MD_CTX_new();
 810     unsigned int hashsize, datalen;
 811     int ret = 0;
 812
 813     if (ctx == NULL || !ossl_statem_export_allowed(s))
 814         goto err;
 815
 816     if (!use_context)
 817         contextlen = 0;
 818
 819     if (EVP_DigestInit_ex(ctx, md, NULL) <= 0
 820             || EVP_DigestUpdate(ctx, context, contextlen) <= 0
 821             || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0
 822             || EVP_DigestInit_ex(ctx, md, NULL) <= 0
 823             || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0
 824             || !tls13_hkdf_expand(s, md, s->exporter_master_secret,
 825                                   (const unsigned char *)label, llen,
 826                                   data, datalen, exportsecret, hashsize, 0)
 827             || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel,
 828                                   sizeof(exporterlabel) - 1, hash, hashsize,
 829                                   out, olen, 0))
 830         goto err;
 831
 832     ret = 1;
 833  err:
 834     EVP_MD_CTX_free(ctx);
 835     return ret;
 836 }
 837
 838 int tls13_export_keying_material_early(SSL *s, unsigned char *out, size_t olen,
 839                                        const char *label, size_t llen,
 840                                        const unsigned char *context,
 841                                        size_t contextlen)
 842 {
 843 #ifdef CHARSET_EBCDIC
 844   static const unsigned char exporterlabel[] = {0x65, 0x78, 0x70, 0x6F, 0x72, 0x74, 0x65, 0x72, 0x00};
 845 #else
 846   static const unsigned char exporterlabel[] = "exporter";
 847 #endif
 848     unsigned char exportsecret[EVP_MAX_MD_SIZE];
 849     unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE];
 850     const EVP_MD *md;
 851     EVP_MD_CTX *ctx = EVP_MD_CTX_new();
 852     unsigned int hashsize, datalen;
 853     int ret = 0;
 854     const SSL_CIPHER *sslcipher;
 855
 856     if (ctx == NULL || !ossl_statem_export_early_allowed(s))
 857         goto err;
 858
 859     if (!s->server && s->max_early_data > 0
 860             && s->session->ext.max_early_data == 0)
 861         sslcipher = SSL_SESSION_get0_cipher(s->psksession);
 862     else
 863         sslcipher = SSL_SESSION_get0_cipher(s->session);
 864
 865     md = ssl_md(sslcipher->algorithm2);
 866
 867     /*
 868      * Calculate the hash value and store it in |data|. The reason why
 869      * the empty string is used is that the definition of TLS-Exporter
 870      * is like so:
 871      *
 872      * TLS-Exporter(label, context_value, key_length) =
 873      *     HKDF-Expand-Label(Derive-Secret(Secret, label, ""),
 874      *                       "exporter", Hash(context_value), key_length)
 875      *
 876      * Derive-Secret(Secret, Label, Messages) =
 877      *       HKDF-Expand-Label(Secret, Label,
 878      *                         Transcript-Hash(Messages), Hash.length)
 879      *
 880      * Here Transcript-Hash is the cipher suite hash algorithm.
 881      */
 882     if (EVP_DigestInit_ex(ctx, md, NULL) <= 0
 883             || EVP_DigestUpdate(ctx, context, contextlen) <= 0
 884             || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0
 885             || EVP_DigestInit_ex(ctx, md, NULL) <= 0
 886             || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0
 887             || !tls13_hkdf_expand(s, md, s->early_exporter_master_secret,
 888                                   (const unsigned char *)label, llen,
 889                                   data, datalen, exportsecret, hashsize, 0)
 890             || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel,
 891                                   sizeof(exporterlabel) - 1, hash, hashsize,
 892                                   out, olen, 0))
 893         goto err;
 894
 895     ret = 1;
 896  err:
 897     EVP_MD_CTX_free(ctx);
 898     return ret;
 899 }