ssl/tls13_enc.c

   1 /*
   2  * Copyright 2016-2020 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(s->ctx->libctx, OSSL_KDF_NAME_HKDF,
  40                                  s->ctx->propq);
  41     EVP_KDF_CTX *kctx;
  42     OSSL_PARAM params[5], *p = params;
  43     int mode = EVP_PKEY_HKDEF_MODE_EXPAND_ONLY;
  44     const char *mdname = EVP_MD_name(md);
  45     int ret;
  46     size_t hkdflabellen;
  47     size_t hashlen;
  48     /*
  49      * 2 bytes for length of derived secret + 1 byte for length of combined
  50      * prefix and label + bytes for the label itself + 1 byte length of hash
  51      * + bytes for the hash itself
  52      */
  53     unsigned char hkdflabel[sizeof(uint16_t) + sizeof(uint8_t)
  54                             + (sizeof(label_prefix) - 1) + TLS13_MAX_LABEL_LEN
  55                             + 1 + EVP_MAX_MD_SIZE];
  56     WPACKET pkt;
  57
  58     kctx = EVP_KDF_CTX_new(kdf);
  59     EVP_KDF_free(kdf);
  60     if (kctx == NULL)
  61         return 0;
  62
  63     if (labellen > TLS13_MAX_LABEL_LEN) {
  64         if (fatal) {
  65             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
  66                      ERR_R_INTERNAL_ERROR);
  67         } else {
  68             /*
  69              * Probably we have been called from SSL_export_keying_material(),
  70              * or SSL_export_keying_material_early().
  71              */
  72             SSLerr(SSL_F_TLS13_HKDF_EXPAND, SSL_R_TLS_ILLEGAL_EXPORTER_LABEL);
  73         }
  74         EVP_KDF_CTX_free(kctx);
  75         return 0;
  76     }
  77
  78     hashlen = EVP_MD_size(md);
  79
  80     if (!WPACKET_init_static_len(&pkt, hkdflabel, sizeof(hkdflabel), 0)
  81             || !WPACKET_put_bytes_u16(&pkt, outlen)
  82             || !WPACKET_start_sub_packet_u8(&pkt)
  83             || !WPACKET_memcpy(&pkt, label_prefix, sizeof(label_prefix) - 1)
  84             || !WPACKET_memcpy(&pkt, label, labellen)
  85             || !WPACKET_close(&pkt)
  86             || !WPACKET_sub_memcpy_u8(&pkt, data, (data == NULL) ? 0 : datalen)
  87             || !WPACKET_get_total_written(&pkt, &hkdflabellen)
  88             || !WPACKET_finish(&pkt)) {
  89         EVP_KDF_CTX_free(kctx);
  90         WPACKET_cleanup(&pkt);
  91         if (fatal)
  92             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
  93                      ERR_R_INTERNAL_ERROR);
  94         else
  95             SSLerr(SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR);
  96         return 0;
  97     }
  98
  99     *p++ = OSSL_PARAM_construct_int(OSSL_KDF_PARAM_MODE, &mode);
 100     *p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
 101                                             (char *)mdname, 0);
 102     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY,
 103                                              (unsigned char *)secret, hashlen);
 104     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_INFO,
 105                                              hkdflabel, hkdflabellen);
 106     *p++ = OSSL_PARAM_construct_end();
 107
 108     ret = EVP_KDF_CTX_set_params(kctx, params) <= 0
 109         || EVP_KDF_derive(kctx, out, outlen) <= 0;
 110
 111     EVP_KDF_CTX_free(kctx);
 112
 113     if (ret != 0) {
 114         if (fatal)
 115             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
 116                      ERR_R_INTERNAL_ERROR);
 117         else
 118             SSLerr(SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR);
 119     }
 120
 121     return ret == 0;
 122 }
 123
 124 /*
 125  * Given a |secret| generate a |key| of length |keylen| bytes. Returns 1 on
 126  * success  0 on failure.
 127  */
 128 int tls13_derive_key(SSL *s, const EVP_MD *md, const unsigned char *secret,
 129                      unsigned char *key, size_t keylen)
 130 {
 131 #ifdef CHARSET_EBCDIC
 132   static const unsigned char keylabel[] ={ 0x6B, 0x65, 0x79, 0x00 };
 133 #else
 134   static const unsigned char keylabel[] = "key";
 135 #endif
 136
 137     return tls13_hkdf_expand(s, md, secret, keylabel, sizeof(keylabel) - 1,
 138                              NULL, 0, key, keylen, 1);
 139 }
 140
 141 /*
 142  * Given a |secret| generate an |iv| of length |ivlen| bytes. Returns 1 on
 143  * success  0 on failure.
 144  */
 145 int tls13_derive_iv(SSL *s, const EVP_MD *md, const unsigned char *secret,
 146                     unsigned char *iv, size_t ivlen)
 147 {
 148 #ifdef CHARSET_EBCDIC
 149   static const unsigned char ivlabel[] = { 0x69, 0x76, 0x00 };
 150 #else
 151   static const unsigned char ivlabel[] = "iv";
 152 #endif
 153
 154     return tls13_hkdf_expand(s, md, secret, ivlabel, sizeof(ivlabel) - 1,
 155                              NULL, 0, iv, ivlen, 1);
 156 }
 157
 158 int tls13_derive_finishedkey(SSL *s, const EVP_MD *md,
 159                              const unsigned char *secret,
 160                              unsigned char *fin, size_t finlen)
 161 {
 162 #ifdef CHARSET_EBCDIC
 163   static const unsigned char finishedlabel[] = { 0x66, 0x69, 0x6E, 0x69, 0x73, 0x68, 0x65, 0x64, 0x00 };
 164 #else
 165   static const unsigned char finishedlabel[] = "finished";
 166 #endif
 167
 168     return tls13_hkdf_expand(s, md, secret, finishedlabel,
 169                              sizeof(finishedlabel) - 1, NULL, 0, fin, finlen, 1);
 170 }
 171
 172 /*
 173  * Given the previous secret |prevsecret| and a new input secret |insecret| of
 174  * length |insecretlen|, generate a new secret and store it in the location
 175  * pointed to by |outsecret|. Returns 1 on success  0 on failure.
 176  */
 177 int tls13_generate_secret(SSL *s, const EVP_MD *md,
 178                           const unsigned char *prevsecret,
 179                           const unsigned char *insecret,
 180                           size_t insecretlen,
 181                           unsigned char *outsecret)
 182 {
 183     size_t mdlen, prevsecretlen;
 184     int mdleni;
 185     int ret;
 186     EVP_KDF *kdf;
 187     EVP_KDF_CTX *kctx;
 188     OSSL_PARAM params[5], *p = params;
 189     int mode = EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY;
 190     const char *mdname = EVP_MD_name(md);
 191 #ifdef CHARSET_EBCDIC
 192     static const char derived_secret_label[] = { 0x64, 0x65, 0x72, 0x69, 0x76, 0x65, 0x64, 0x00 };
 193 #else
 194     static const char derived_secret_label[] = "derived";
 195 #endif
 196     unsigned char preextractsec[EVP_MAX_MD_SIZE];
 197
 198     kdf = EVP_KDF_fetch(s->ctx->libctx, OSSL_KDF_NAME_HKDF, s->ctx->propq);
 199     kctx = EVP_KDF_CTX_new(kdf);
 200     EVP_KDF_free(kdf);
 201     if (kctx == NULL) {
 202         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
 203                  ERR_R_INTERNAL_ERROR);
 204         return 0;
 205     }
 206
 207     mdleni = EVP_MD_size(md);
 208     /* Ensure cast to size_t is safe */
 209     if (!ossl_assert(mdleni >= 0)) {
 210         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
 211                  ERR_R_INTERNAL_ERROR);
 212         EVP_KDF_CTX_free(kctx);
 213         return 0;
 214     }
 215     mdlen = (size_t)mdleni;
 216
 217     if (insecret == NULL) {
 218         insecret = default_zeros;
 219         insecretlen = mdlen;
 220     }
 221     if (prevsecret == NULL) {
 222         prevsecret = default_zeros;
 223         prevsecretlen = 0;
 224     } else {
 225         EVP_MD_CTX *mctx = EVP_MD_CTX_new();
 226         unsigned char hash[EVP_MAX_MD_SIZE];
 227
 228         /* The pre-extract derive step uses a hash of no messages */
 229         if (mctx == NULL
 230                 || EVP_DigestInit_ex(mctx, md, NULL) <= 0
 231                 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
 232             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
 233                      ERR_R_INTERNAL_ERROR);
 234             EVP_MD_CTX_free(mctx);
 235             EVP_KDF_CTX_free(kctx);
 236             return 0;
 237         }
 238         EVP_MD_CTX_free(mctx);
 239
 240         /* Generate the pre-extract secret */
 241         if (!tls13_hkdf_expand(s, md, prevsecret,
 242                                (unsigned char *)derived_secret_label,
 243                                sizeof(derived_secret_label) - 1, hash, mdlen,
 244                                preextractsec, mdlen, 1)) {
 245             /* SSLfatal() already called */
 246             EVP_KDF_CTX_free(kctx);
 247             return 0;
 248         }
 249
 250         prevsecret = preextractsec;
 251         prevsecretlen = mdlen;
 252     }
 253
 254     *p++ = OSSL_PARAM_construct_int(OSSL_KDF_PARAM_MODE, &mode);
 255     *p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
 256                                             (char *)mdname, 0);
 257     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY,
 258                                              (unsigned char *)insecret,
 259                                              insecretlen);
 260     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SALT,
 261                                              (unsigned char *)prevsecret,
 262                                              prevsecretlen);
 263     *p++ = OSSL_PARAM_construct_end();
 264
 265     ret = EVP_KDF_CTX_set_params(kctx, params) <= 0
 266         || EVP_KDF_derive(kctx, outsecret, mdlen) <= 0;
 267
 268     if (ret != 0)
 269         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
 270                  ERR_R_INTERNAL_ERROR);
 271
 272     EVP_KDF_CTX_free(kctx);
 273     if (prevsecret == preextractsec)
 274         OPENSSL_cleanse(preextractsec, mdlen);
 275     return ret == 0;
 276 }
 277
 278 /*
 279  * Given an input secret |insecret| of length |insecretlen| generate the
 280  * handshake secret. This requires the early secret to already have been
 281  * generated. Returns 1 on success  0 on failure.
 282  */
 283 int tls13_generate_handshake_secret(SSL *s, const unsigned char *insecret,
 284                                 size_t insecretlen)
 285 {
 286     /* Calls SSLfatal() if required */
 287     return tls13_generate_secret(s, ssl_handshake_md(s), s->early_secret,
 288                                  insecret, insecretlen,
 289                                  (unsigned char *)&s->handshake_secret);
 290 }
 291
 292 /*
 293  * Given the handshake secret |prev| of length |prevlen| generate the master
 294  * secret and store its length in |*secret_size|. Returns 1 on success  0 on
 295  * failure.
 296  */
 297 int tls13_generate_master_secret(SSL *s, unsigned char *out,
 298                                  unsigned char *prev, size_t prevlen,
 299                                  size_t *secret_size)
 300 {
 301     const EVP_MD *md = ssl_handshake_md(s);
 302
 303     *secret_size = EVP_MD_size(md);
 304     /* Calls SSLfatal() if required */
 305     return tls13_generate_secret(s, md, prev, NULL, 0, out);
 306 }
 307
 308 /*
 309  * Generates the mac for the Finished message. Returns the length of the MAC or
 310  * 0 on error.
 311  */
 312 size_t tls13_final_finish_mac(SSL *s, const char *str, size_t slen,
 313                              unsigned char *out)
 314 {
 315     const char *mdname = EVP_MD_name(ssl_handshake_md(s));
 316     EVP_MAC *hmac = EVP_MAC_fetch(s->ctx->libctx, "HMAC", s->ctx->propq);
 317     unsigned char hash[EVP_MAX_MD_SIZE];
 318     unsigned char finsecret[EVP_MAX_MD_SIZE];
 319     size_t hashlen, ret = 0;
 320     EVP_MAC_CTX *ctx = NULL;
 321     OSSL_PARAM params[4], *p = params;
 322
 323     if (hmac == NULL) {
 324         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_FINAL_FINISH_MAC,
 325                  ERR_R_INTERNAL_ERROR);
 326         goto err;
 327     }
 328
 329     /* Safe to cast away const here since we're not "getting" any data */
 330     *p++ = OSSL_PARAM_construct_utf8_string(OSSL_ALG_PARAM_DIGEST,
 331                                             (char *)mdname, 0);
 332     if (s->ctx->propq != NULL)
 333         *p++ = OSSL_PARAM_construct_utf8_string(OSSL_ALG_PARAM_PROPERTIES,
 334                                                 (char *)s->ctx->propq,
 335                                                 0);
 336
 337     if (!ssl_handshake_hash(s, hash, sizeof(hash), &hashlen)) {
 338         /* SSLfatal() already called */
 339         goto err;
 340     }
 341
 342     if (str == s->method->ssl3_enc->server_finished_label) {
 343         *p++ = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
 344                                                  s->server_finished_secret,
 345                                                  hashlen);
 346     } else if (SSL_IS_FIRST_HANDSHAKE(s)) {
 347         *p++ = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
 348                                                  s->client_finished_secret,
 349                                                  hashlen);
 350     } else {
 351         if (!tls13_derive_finishedkey(s, ssl_handshake_md(s),
 352                                       s->client_app_traffic_secret,
 353                                       finsecret, hashlen))
 354             goto err;
 355
 356         *p++ = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY, finsecret,
 357                                                  hashlen);
 358     }
 359     *p++ = OSSL_PARAM_construct_end();
 360
 361     ctx = EVP_MAC_CTX_new(hmac);
 362     if (ctx == NULL
 363             || !EVP_MAC_CTX_set_params(ctx, params)
 364             || !EVP_MAC_init(ctx)
 365             || !EVP_MAC_update(ctx, hash, hashlen)
 366                /* outsize as per sizeof(peer_finish_md) */
 367             || !EVP_MAC_final(ctx, out, &hashlen, EVP_MAX_MD_SIZE * 2)) {
 368         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_FINAL_FINISH_MAC,
 369                  ERR_R_INTERNAL_ERROR);
 370         goto err;
 371     }
 372
 373     ret = hashlen;
 374  err:
 375     OPENSSL_cleanse(finsecret, sizeof(finsecret));
 376     EVP_MAC_CTX_free(ctx);
 377     EVP_MAC_free(hmac);
 378     return ret;
 379 }
 380
 381 /*
 382  * There isn't really a key block in TLSv1.3, but we still need this function
 383  * for initialising the cipher and hash. Returns 1 on success or 0 on failure.
 384  */
 385 int tls13_setup_key_block(SSL *s)
 386 {
 387     const EVP_CIPHER *c;
 388     const EVP_MD *hash;
 389
 390     s->session->cipher = s->s3.tmp.new_cipher;
 391     if (!ssl_cipher_get_evp(s->ctx, s->session, &c, &hash, NULL, NULL, NULL,
 392                             0)) {
 393         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_SETUP_KEY_BLOCK,
 394                  SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
 395         return 0;
 396     }
 397
 398     ssl_evp_cipher_free(s->s3.tmp.new_sym_enc);
 399     s->s3.tmp.new_sym_enc = c;
 400     ssl_evp_md_free(s->s3.tmp.new_hash);
 401     s->s3.tmp.new_hash = hash;
 402
 403     return 1;
 404 }
 405
 406 static int derive_secret_key_and_iv(SSL *s, int sending, const EVP_MD *md,
 407                                     const EVP_CIPHER *ciph,
 408                                     const unsigned char *insecret,
 409                                     const unsigned char *hash,
 410                                     const unsigned char *label,
 411                                     size_t labellen, unsigned char *secret,
 412                                     unsigned char *iv, EVP_CIPHER_CTX *ciph_ctx)
 413 {
 414     unsigned char key[EVP_MAX_KEY_LENGTH];
 415     size_t ivlen, keylen, taglen;
 416     int hashleni = EVP_MD_size(md);
 417     size_t hashlen;
 418
 419     /* Ensure cast to size_t is safe */
 420     if (!ossl_assert(hashleni >= 0)) {
 421         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DERIVE_SECRET_KEY_AND_IV,
 422                  ERR_R_EVP_LIB);
 423         goto err;
 424     }
 425     hashlen = (size_t)hashleni;
 426
 427     if (!tls13_hkdf_expand(s, md, insecret, label, labellen, hash, hashlen,
 428                            secret, hashlen, 1)) {
 429         /* SSLfatal() already called */
 430         goto err;
 431     }
 432
 433     /* TODO(size_t): convert me */
 434     keylen = EVP_CIPHER_key_length(ciph);
 435     if (EVP_CIPHER_mode(ciph) == EVP_CIPH_CCM_MODE) {
 436         uint32_t algenc;
 437
 438         ivlen = EVP_CCM_TLS_IV_LEN;
 439         if (s->s3.tmp.new_cipher == NULL) {
 440             /* We've not selected a cipher yet - we must be doing early data */
 441             algenc = s->session->cipher->algorithm_enc;
 442         } else {
 443             algenc = s->s3.tmp.new_cipher->algorithm_enc;
 444         }
 445         if (algenc & (SSL_AES128CCM8 | SSL_AES256CCM8))
 446             taglen = EVP_CCM8_TLS_TAG_LEN;
 447          else
 448             taglen = EVP_CCM_TLS_TAG_LEN;
 449     } else {
 450         ivlen = EVP_CIPHER_iv_length(ciph);
 451         taglen = 0;
 452     }
 453
 454     if (!tls13_derive_key(s, md, secret, key, keylen)
 455             || !tls13_derive_iv(s, md, secret, iv, ivlen)) {
 456         /* SSLfatal() already called */
 457         goto err;
 458     }
 459
 460     if (EVP_CipherInit_ex(ciph_ctx, ciph, NULL, NULL, NULL, sending) <= 0
 461         || !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
 462         || (taglen != 0 && !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_TAG,
 463                                                 taglen, NULL))
 464         || EVP_CipherInit_ex(ciph_ctx, NULL, NULL, key, NULL, -1) <= 0) {
 465         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DERIVE_SECRET_KEY_AND_IV,
 466                  ERR_R_EVP_LIB);
 467         goto err;
 468     }
 469
 470     return 1;
 471  err:
 472     OPENSSL_cleanse(key, sizeof(key));
 473     return 0;
 474 }
 475
 476 int tls13_change_cipher_state(SSL *s, int which)
 477 {
 478 #ifdef CHARSET_EBCDIC
 479   static const unsigned char client_early_traffic[]       = {0x63, 0x20, 0x65, 0x20,       /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
 480   static const unsigned char client_handshake_traffic[]   = {0x63, 0x20, 0x68, 0x73, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
 481   static const unsigned char client_application_traffic[] = {0x63, 0x20, 0x61, 0x70, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
 482   static const unsigned char server_handshake_traffic[]   = {0x73, 0x20, 0x68, 0x73, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
 483   static const unsigned char server_application_traffic[] = {0x73, 0x20, 0x61, 0x70, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
 484   static const unsigned char exporter_master_secret[] = {0x65, 0x78, 0x70, 0x20,                    /* master*/  0x6D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x00};
 485   static const unsigned char resumption_master_secret[] = {0x72, 0x65, 0x73, 0x20,                  /* master*/  0x6D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x00};
 486   static const unsigned char early_exporter_master_secret[] = {0x65, 0x20, 0x65, 0x78, 0x70, 0x20,  /* master*/  0x6D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x00};
 487 #else
 488     static const unsigned char client_early_traffic[] = "c e traffic";
 489     static const unsigned char client_handshake_traffic[] = "c hs traffic";
 490     static const unsigned char client_application_traffic[] = "c ap traffic";
 491     static const unsigned char server_handshake_traffic[] = "s hs traffic";
 492     static const unsigned char server_application_traffic[] = "s ap traffic";
 493     static const unsigned char exporter_master_secret[] = "exp master";
 494     static const unsigned char resumption_master_secret[] = "res master";
 495     static const unsigned char early_exporter_master_secret[] = "e exp master";
 496 #endif
 497     unsigned char *iv;
 498     unsigned char secret[EVP_MAX_MD_SIZE];
 499     unsigned char hashval[EVP_MAX_MD_SIZE];
 500     unsigned char *hash = hashval;
 501     unsigned char *insecret;
 502     unsigned char *finsecret = NULL;
 503     const char *log_label = NULL;
 504     EVP_CIPHER_CTX *ciph_ctx;
 505     size_t finsecretlen = 0;
 506     const unsigned char *label;
 507     size_t labellen, hashlen = 0;
 508     int ret = 0;
 509     const EVP_MD *md = NULL;
 510     const EVP_CIPHER *cipher = NULL;
 511
 512     if (which & SSL3_CC_READ) {
 513         if (s->enc_read_ctx != NULL) {
 514             EVP_CIPHER_CTX_reset(s->enc_read_ctx);
 515         } else {
 516             s->enc_read_ctx = EVP_CIPHER_CTX_new();
 517             if (s->enc_read_ctx == NULL) {
 518                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 519                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
 520                 goto err;
 521             }
 522         }
 523         ciph_ctx = s->enc_read_ctx;
 524         iv = s->read_iv;
 525
 526         RECORD_LAYER_reset_read_sequence(&s->rlayer);
 527     } else {
 528         s->statem.enc_write_state = ENC_WRITE_STATE_INVALID;
 529         if (s->enc_write_ctx != NULL) {
 530             EVP_CIPHER_CTX_reset(s->enc_write_ctx);
 531         } else {
 532             s->enc_write_ctx = EVP_CIPHER_CTX_new();
 533             if (s->enc_write_ctx == NULL) {
 534                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 535                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
 536                 goto err;
 537             }
 538         }
 539         ciph_ctx = s->enc_write_ctx;
 540         iv = s->write_iv;
 541
 542         RECORD_LAYER_reset_write_sequence(&s->rlayer);
 543     }
 544
 545     if (((which & SSL3_CC_CLIENT) && (which & SSL3_CC_WRITE))
 546             || ((which & SSL3_CC_SERVER) && (which & SSL3_CC_READ))) {
 547         if (which & SSL3_CC_EARLY) {
 548             EVP_MD_CTX *mdctx = NULL;
 549             long handlen;
 550             void *hdata;
 551             unsigned int hashlenui;
 552             const SSL_CIPHER *sslcipher = SSL_SESSION_get0_cipher(s->session);
 553
 554             insecret = s->early_secret;
 555             label = client_early_traffic;
 556             labellen = sizeof(client_early_traffic) - 1;
 557             log_label = CLIENT_EARLY_LABEL;
 558
 559             handlen = BIO_get_mem_data(s->s3.handshake_buffer, &hdata);
 560             if (handlen <= 0) {
 561                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 562                          SSL_F_TLS13_CHANGE_CIPHER_STATE,
 563                          SSL_R_BAD_HANDSHAKE_LENGTH);
 564                 goto err;
 565             }
 566
 567             if (s->early_data_state == SSL_EARLY_DATA_CONNECTING
 568                     && s->max_early_data > 0
 569                     && s->session->ext.max_early_data == 0) {
 570                 /*
 571                  * If we are attempting to send early data, and we've decided to
 572                  * actually do it but max_early_data in s->session is 0 then we
 573                  * must be using an external PSK.
 574                  */
 575                 if (!ossl_assert(s->psksession != NULL
 576                         && s->max_early_data ==
 577                            s->psksession->ext.max_early_data)) {
 578                     SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 579                              SSL_F_TLS13_CHANGE_CIPHER_STATE,
 580                              ERR_R_INTERNAL_ERROR);
 581                     goto err;
 582                 }
 583                 sslcipher = SSL_SESSION_get0_cipher(s->psksession);
 584             }
 585             if (sslcipher == NULL) {
 586                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 587                          SSL_F_TLS13_CHANGE_CIPHER_STATE, SSL_R_BAD_PSK);
 588                 goto err;
 589             }
 590
 591             /*
 592              * We need to calculate the handshake digest using the digest from
 593              * the session. We haven't yet selected our ciphersuite so we can't
 594              * use ssl_handshake_md().
 595              */
 596             mdctx = EVP_MD_CTX_new();
 597             if (mdctx == NULL) {
 598                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 599                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
 600                 goto err;
 601             }
 602
 603             /*
 604              * This ups the ref count on cipher so we better make sure we free
 605              * it again
 606              */
 607             if (!ssl_cipher_get_evp_cipher(s->ctx, sslcipher, &cipher)) {
 608                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 609                          SSL_F_TLS13_CHANGE_CIPHER_STATE,
 610                          SSL_R_ALGORITHM_FETCH_FAILED);
 611                 goto err;
 612             }
 613
 614             md = ssl_md(s->ctx, sslcipher->algorithm2);
 615             if (md == NULL || !EVP_DigestInit_ex(mdctx, md, NULL)
 616                     || !EVP_DigestUpdate(mdctx, hdata, handlen)
 617                     || !EVP_DigestFinal_ex(mdctx, hashval, &hashlenui)) {
 618                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 619                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
 620                 EVP_MD_CTX_free(mdctx);
 621                 goto err;
 622             }
 623             hashlen = hashlenui;
 624             EVP_MD_CTX_free(mdctx);
 625
 626             if (!tls13_hkdf_expand(s, md, insecret,
 627                                    early_exporter_master_secret,
 628                                    sizeof(early_exporter_master_secret) - 1,
 629                                    hashval, hashlen,
 630                                    s->early_exporter_master_secret, hashlen,
 631                                    1)) {
 632                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
 633                          SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
 634                 goto err;
 635             }
 636
 637             if (!ssl_log_secret(s, EARLY_EXPORTER_SECRET_LABEL,
 638                                 s->early_exporter_master_secret, hashlen)) {
 639                 /* SSLfatal() already called */
 640                 goto err;
 641             }
 642         } else if (which & SSL3_CC_HANDSHAKE) {
 643             insecret = s->handshake_secret;
 644             finsecret = s->client_finished_secret;
 645             finsecretlen = EVP_MD_size(ssl_handshake_md(s));
 646             label = client_handshake_traffic;
 647             labellen = sizeof(client_handshake_traffic) - 1;
 648             log_label = CLIENT_HANDSHAKE_LABEL;
 649             /*
 650              * The handshake hash used for the server read/client write handshake
 651              * traffic secret is the same as the hash for the server
 652              * write/client read handshake traffic secret. However, if we
 653              * processed early data then we delay changing the server
 654              * read/client write cipher state until later, and the handshake
 655              * hashes have moved on. Therefore we use the value saved earlier
 656              * when we did the server write/client read change cipher state.
 657              */
 658             hash = s->handshake_traffic_hash;
 659         } else {
 660             insecret = s->master_secret;
 661             label = client_application_traffic;
 662             labellen = sizeof(client_application_traffic) - 1;
 663             log_label = CLIENT_APPLICATION_LABEL;
 664             /*
 665              * For this we only use the handshake hashes up until the server
 666              * Finished hash. We do not include the client's Finished, which is
 667              * what ssl_handshake_hash() would give us. Instead we use the
 668              * previously saved value.
 669              */
 670             hash = s->server_finished_hash;
 671         }
 672     } else {
 673         /* Early data never applies to client-read/server-write */
 674         if (which & SSL3_CC_HANDSHAKE) {
 675             insecret = s->handshake_secret;
 676             finsecret = s->server_finished_secret;
 677             finsecretlen = EVP_MD_size(ssl_handshake_md(s));
 678             label = server_handshake_traffic;
 679             labellen = sizeof(server_handshake_traffic) - 1;
 680             log_label = SERVER_HANDSHAKE_LABEL;
 681         } else {
 682             insecret = s->master_secret;
 683             label = server_application_traffic;
 684             labellen = sizeof(server_application_traffic) - 1;
 685             log_label = SERVER_APPLICATION_LABEL;
 686         }
 687     }
 688
 689     if (!(which & SSL3_CC_EARLY)) {
 690         md = ssl_handshake_md(s);
 691         cipher = s->s3.tmp.new_sym_enc;
 692         if (!ssl3_digest_cached_records(s, 1)
 693                 || !ssl_handshake_hash(s, hashval, sizeof(hashval), &hashlen)) {
 694             /* SSLfatal() already called */;
 695             goto err;
 696         }
 697     }
 698
 699     /*
 700      * Save the hash of handshakes up to now for use when we calculate the
 701      * client application traffic secret
 702      */
 703     if (label == server_application_traffic)
 704         memcpy(s->server_finished_hash, hashval, hashlen);
 705
 706     if (label == server_handshake_traffic)
 707         memcpy(s->handshake_traffic_hash, hashval, hashlen);
 708
 709     if (label == client_application_traffic) {
 710         /*
 711          * We also create the resumption master secret, but this time use the
 712          * hash for the whole handshake including the Client Finished
 713          */
 714         if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
 715                                resumption_master_secret,
 716                                sizeof(resumption_master_secret) - 1,
 717                                hashval, hashlen, s->resumption_master_secret,
 718                                hashlen, 1)) {
 719             /* SSLfatal() already called */
 720             goto err;
 721         }
 722     }
 723
 724     if (!derive_secret_key_and_iv(s, which & SSL3_CC_WRITE, md, cipher,
 725                                   insecret, hash, label, labellen, secret, iv,
 726                                   ciph_ctx)) {
 727         /* SSLfatal() already called */
 728         goto err;
 729     }
 730
 731     if (label == server_application_traffic) {
 732         memcpy(s->server_app_traffic_secret, secret, hashlen);
 733         /* Now we create the exporter master secret */
 734         if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
 735                                exporter_master_secret,
 736                                sizeof(exporter_master_secret) - 1,
 737                                hash, hashlen, s->exporter_master_secret,
 738                                hashlen, 1)) {
 739             /* SSLfatal() already called */
 740             goto err;
 741         }
 742
 743         if (!ssl_log_secret(s, EXPORTER_SECRET_LABEL, s->exporter_master_secret,
 744                             hashlen)) {
 745             /* SSLfatal() already called */
 746             goto err;
 747         }
 748     } else if (label == client_application_traffic)
 749         memcpy(s->client_app_traffic_secret, secret, hashlen);
 750
 751     if (!ssl_log_secret(s, log_label, secret, hashlen)) {
 752         /* SSLfatal() already called */
 753         goto err;
 754     }
 755
 756     if (finsecret != NULL
 757             && !tls13_derive_finishedkey(s, ssl_handshake_md(s), secret,
 758                                          finsecret, finsecretlen)) {
 759         /* SSLfatal() already called */
 760         goto err;
 761     }
 762
 763     if (!s->server && label == client_early_traffic)
 764         s->statem.enc_write_state = ENC_WRITE_STATE_WRITE_PLAIN_ALERTS;
 765     else
 766         s->statem.enc_write_state = ENC_WRITE_STATE_VALID;
 767     ret = 1;
 768  err:
 769     if ((which & SSL3_CC_EARLY) != 0) {
 770         /* We up-refed this so now we need to down ref */
 771         ssl_evp_cipher_free(cipher);
 772     }
 773     OPENSSL_cleanse(secret, sizeof(secret));
 774     return ret;
 775 }
 776
 777 int tls13_update_key(SSL *s, int sending)
 778 {
 779 #ifdef CHARSET_EBCDIC
 780   static const unsigned char application_traffic[] = { 0x74, 0x72 ,0x61 ,0x66 ,0x66 ,0x69 ,0x63 ,0x20 ,0x75 ,0x70 ,0x64, 0x00};
 781 #else
 782   static const unsigned char application_traffic[] = "traffic upd";
 783 #endif
 784     const EVP_MD *md = ssl_handshake_md(s);
 785     size_t hashlen = EVP_MD_size(md);
 786     unsigned char *insecret, *iv;
 787     unsigned char secret[EVP_MAX_MD_SIZE];
 788     EVP_CIPHER_CTX *ciph_ctx;
 789     int ret = 0;
 790
 791     if (s->server == sending)
 792         insecret = s->server_app_traffic_secret;
 793     else
 794         insecret = s->client_app_traffic_secret;
 795
 796     if (sending) {
 797         s->statem.enc_write_state = ENC_WRITE_STATE_INVALID;
 798         iv = s->write_iv;
 799         ciph_ctx = s->enc_write_ctx;
 800         RECORD_LAYER_reset_write_sequence(&s->rlayer);
 801     } else {
 802         iv = s->read_iv;
 803         ciph_ctx = s->enc_read_ctx;
 804         RECORD_LAYER_reset_read_sequence(&s->rlayer);
 805     }
 806
 807     if (!derive_secret_key_and_iv(s, sending, ssl_handshake_md(s),
 808                                   s->s3.tmp.new_sym_enc, insecret, NULL,
 809                                   application_traffic,
 810                                   sizeof(application_traffic) - 1, secret, iv,
 811                                   ciph_ctx)) {
 812         /* SSLfatal() already called */
 813         goto err;
 814     }
 815
 816     memcpy(insecret, secret, hashlen);
 817
 818     s->statem.enc_write_state = ENC_WRITE_STATE_VALID;
 819     ret = 1;
 820  err:
 821     OPENSSL_cleanse(secret, sizeof(secret));
 822     return ret;
 823 }
 824
 825 int tls13_alert_code(int code)
 826 {
 827     /* There are 2 additional alerts in TLSv1.3 compared to TLSv1.2 */
 828     if (code == SSL_AD_MISSING_EXTENSION || code == SSL_AD_CERTIFICATE_REQUIRED)
 829         return code;
 830
 831     return tls1_alert_code(code);
 832 }
 833
 834 int tls13_export_keying_material(SSL *s, unsigned char *out, size_t olen,
 835                                  const char *label, size_t llen,
 836                                  const unsigned char *context,
 837                                  size_t contextlen, int use_context)
 838 {
 839     unsigned char exportsecret[EVP_MAX_MD_SIZE];
 840 #ifdef CHARSET_EBCDIC
 841     static const unsigned char exporterlabel[] = {0x65, 0x78, 0x70, 0x6F, 0x72, 0x74, 0x65, 0x72, 0x00};
 842 #else
 843     static const unsigned char exporterlabel[] = "exporter";
 844 #endif
 845     unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE];
 846     const EVP_MD *md = ssl_handshake_md(s);
 847     EVP_MD_CTX *ctx = EVP_MD_CTX_new();
 848     unsigned int hashsize, datalen;
 849     int ret = 0;
 850
 851     if (ctx == NULL || !ossl_statem_export_allowed(s))
 852         goto err;
 853
 854     if (!use_context)
 855         contextlen = 0;
 856
 857     if (EVP_DigestInit_ex(ctx, md, NULL) <= 0
 858             || EVP_DigestUpdate(ctx, context, contextlen) <= 0
 859             || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0
 860             || EVP_DigestInit_ex(ctx, md, NULL) <= 0
 861             || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0
 862             || !tls13_hkdf_expand(s, md, s->exporter_master_secret,
 863                                   (const unsigned char *)label, llen,
 864                                   data, datalen, exportsecret, hashsize, 0)
 865             || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel,
 866                                   sizeof(exporterlabel) - 1, hash, hashsize,
 867                                   out, olen, 0))
 868         goto err;
 869
 870     ret = 1;
 871  err:
 872     EVP_MD_CTX_free(ctx);
 873     return ret;
 874 }
 875
 876 int tls13_export_keying_material_early(SSL *s, unsigned char *out, size_t olen,
 877                                        const char *label, size_t llen,
 878                                        const unsigned char *context,
 879                                        size_t contextlen)
 880 {
 881 #ifdef CHARSET_EBCDIC
 882   static const unsigned char exporterlabel[] = {0x65, 0x78, 0x70, 0x6F, 0x72, 0x74, 0x65, 0x72, 0x00};
 883 #else
 884   static const unsigned char exporterlabel[] = "exporter";
 885 #endif
 886     unsigned char exportsecret[EVP_MAX_MD_SIZE];
 887     unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE];
 888     const EVP_MD *md;
 889     EVP_MD_CTX *ctx = EVP_MD_CTX_new();
 890     unsigned int hashsize, datalen;
 891     int ret = 0;
 892     const SSL_CIPHER *sslcipher;
 893
 894     if (ctx == NULL || !ossl_statem_export_early_allowed(s))
 895         goto err;
 896
 897     if (!s->server && s->max_early_data > 0
 898             && s->session->ext.max_early_data == 0)
 899         sslcipher = SSL_SESSION_get0_cipher(s->psksession);
 900     else
 901         sslcipher = SSL_SESSION_get0_cipher(s->session);
 902
 903     md = ssl_md(s->ctx, sslcipher->algorithm2);
 904
 905     /*
 906      * Calculate the hash value and store it in |data|. The reason why
 907      * the empty string is used is that the definition of TLS-Exporter
 908      * is like so:
 909      *
 910      * TLS-Exporter(label, context_value, key_length) =
 911      *     HKDF-Expand-Label(Derive-Secret(Secret, label, ""),
 912      *                       "exporter", Hash(context_value), key_length)
 913      *
 914      * Derive-Secret(Secret, Label, Messages) =
 915      *       HKDF-Expand-Label(Secret, Label,
 916      *                         Transcript-Hash(Messages), Hash.length)
 917      *
 918      * Here Transcript-Hash is the cipher suite hash algorithm.
 919      */
 920     if (EVP_DigestInit_ex(ctx, md, NULL) <= 0
 921             || EVP_DigestUpdate(ctx, context, contextlen) <= 0
 922             || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0
 923             || EVP_DigestInit_ex(ctx, md, NULL) <= 0
 924             || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0
 925             || !tls13_hkdf_expand(s, md, s->early_exporter_master_secret,
 926                                   (const unsigned char *)label, llen,
 927                                   data, datalen, exportsecret, hashsize, 0)
 928             || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel,
 929                                   sizeof(exporterlabel) - 1, hash, hashsize,
 930                                   out, olen, 0))
 931         goto err;
 932
 933     ret = 1;
 934  err:
 935     EVP_MD_CTX_free(ctx);
 936     return ret;
 937 }