ssl/tls13_enc.c

   1 /*
   2  * Copyright 2016-2021 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/ktls.h"
  13 #include "record/record_local.h"
  14 #include "internal/cryptlib.h"
  15 #include <openssl/evp.h>
  16 #include <openssl/kdf.h>
  17 #include <openssl/core_names.h>
  18
  19 #define TLS13_MAX_LABEL_LEN     249
  20
  21 /* Always filled with zeros */
  22 static const unsigned char default_zeros[EVP_MAX_MD_SIZE];
  23
  24 /*
  25  * Given a |secret|; a |label| of length |labellen|; and |data| of length
  26  * |datalen| (e.g. typically a hash of the handshake messages), derive a new
  27  * secret |outlen| bytes long and store it in the location pointed to be |out|.
  28  * The |data| value may be zero length. Any errors will be treated as fatal if
  29  * |fatal| is set. Returns 1 on success  0 on failure.
  30  */
  31 int tls13_hkdf_expand(SSL *s, const EVP_MD *md, const unsigned char *secret,
  32                              const unsigned char *label, size_t labellen,
  33                              const unsigned char *data, size_t datalen,
  34                              unsigned char *out, size_t outlen, int fatal)
  35 {
  36 #ifdef CHARSET_EBCDIC
  37     static const unsigned char label_prefix[] = { 0x74, 0x6C, 0x73, 0x31, 0x33, 0x20, 0x00 };
  38 #else
  39     static const unsigned char label_prefix[] = "tls13 ";
  40 #endif
  41     EVP_KDF *kdf = EVP_KDF_fetch(s->ctx->libctx, OSSL_KDF_NAME_HKDF,
  42                                  s->ctx->propq);
  43     EVP_KDF_CTX *kctx;
  44     OSSL_PARAM params[5], *p = params;
  45     int mode = EVP_PKEY_HKDEF_MODE_EXPAND_ONLY;
  46     const char *mdname = EVP_MD_name(md);
  47     int ret;
  48     size_t hkdflabellen;
  49     size_t hashlen;
  50     /*
  51      * 2 bytes for length of derived secret + 1 byte for length of combined
  52      * prefix and label + bytes for the label itself + 1 byte length of hash
  53      * + bytes for the hash itself
  54      */
  55     unsigned char hkdflabel[sizeof(uint16_t) + sizeof(uint8_t)
  56                             + (sizeof(label_prefix) - 1) + TLS13_MAX_LABEL_LEN
  57                             + 1 + EVP_MAX_MD_SIZE];
  58     WPACKET pkt;
  59
  60     kctx = EVP_KDF_CTX_new(kdf);
  61     EVP_KDF_free(kdf);
  62     if (kctx == NULL)
  63         return 0;
  64
  65     if (labellen > TLS13_MAX_LABEL_LEN) {
  66         if (fatal) {
  67             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
  68         } else {
  69             /*
  70              * Probably we have been called from SSL_export_keying_material(),
  71              * or SSL_export_keying_material_early().
  72              */
  73             ERR_raise(ERR_LIB_SSL, SSL_R_TLS_ILLEGAL_EXPORTER_LABEL);
  74         }
  75         EVP_KDF_CTX_free(kctx);
  76         return 0;
  77     }
  78
  79     hashlen = EVP_MD_size(md);
  80
  81     if (!WPACKET_init_static_len(&pkt, hkdflabel, sizeof(hkdflabel), 0)
  82             || !WPACKET_put_bytes_u16(&pkt, outlen)
  83             || !WPACKET_start_sub_packet_u8(&pkt)
  84             || !WPACKET_memcpy(&pkt, label_prefix, sizeof(label_prefix) - 1)
  85             || !WPACKET_memcpy(&pkt, label, labellen)
  86             || !WPACKET_close(&pkt)
  87             || !WPACKET_sub_memcpy_u8(&pkt, data, (data == NULL) ? 0 : datalen)
  88             || !WPACKET_get_total_written(&pkt, &hkdflabellen)
  89             || !WPACKET_finish(&pkt)) {
  90         EVP_KDF_CTX_free(kctx);
  91         WPACKET_cleanup(&pkt);
  92         if (fatal)
  93             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
  94         else
  95             ERR_raise(ERR_LIB_SSL, 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, ERR_R_INTERNAL_ERROR);
 116         else
 117             ERR_raise(ERR_LIB_SSL, 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(s->ctx->libctx, OSSL_KDF_NAME_HKDF, s->ctx->propq);
 198     kctx = EVP_KDF_CTX_new(kdf);
 199     EVP_KDF_free(kdf);
 200     if (kctx == NULL) {
 201         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 202         return 0;
 203     }
 204
 205     mdleni = EVP_MD_size(md);
 206     /* Ensure cast to size_t is safe */
 207     if (!ossl_assert(mdleni >= 0)) {
 208         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 209         EVP_KDF_CTX_free(kctx);
 210         return 0;
 211     }
 212     mdlen = (size_t)mdleni;
 213
 214     if (insecret == NULL) {
 215         insecret = default_zeros;
 216         insecretlen = mdlen;
 217     }
 218     if (prevsecret == NULL) {
 219         prevsecret = default_zeros;
 220         prevsecretlen = 0;
 221     } else {
 222         EVP_MD_CTX *mctx = EVP_MD_CTX_new();
 223         unsigned char hash[EVP_MAX_MD_SIZE];
 224
 225         /* The pre-extract derive step uses a hash of no messages */
 226         if (mctx == NULL
 227                 || EVP_DigestInit_ex(mctx, md, NULL) <= 0
 228                 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
 229             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 230             EVP_MD_CTX_free(mctx);
 231             EVP_KDF_CTX_free(kctx);
 232             return 0;
 233         }
 234         EVP_MD_CTX_free(mctx);
 235
 236         /* Generate the pre-extract secret */
 237         if (!tls13_hkdf_expand(s, md, prevsecret,
 238                                (unsigned char *)derived_secret_label,
 239                                sizeof(derived_secret_label) - 1, hash, mdlen,
 240                                preextractsec, mdlen, 1)) {
 241             /* SSLfatal() already called */
 242             EVP_KDF_CTX_free(kctx);
 243             return 0;
 244         }
 245
 246         prevsecret = preextractsec;
 247         prevsecretlen = mdlen;
 248     }
 249
 250     *p++ = OSSL_PARAM_construct_int(OSSL_KDF_PARAM_MODE, &mode);
 251     *p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
 252                                             (char *)mdname, 0);
 253     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY,
 254                                              (unsigned char *)insecret,
 255                                              insecretlen);
 256     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SALT,
 257                                              (unsigned char *)prevsecret,
 258                                              prevsecretlen);
 259     *p++ = OSSL_PARAM_construct_end();
 260
 261     ret = EVP_KDF_CTX_set_params(kctx, params) <= 0
 262         || EVP_KDF_derive(kctx, outsecret, mdlen) <= 0;
 263
 264     if (ret != 0)
 265         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 266
 267     EVP_KDF_CTX_free(kctx);
 268     if (prevsecret == preextractsec)
 269         OPENSSL_cleanse(preextractsec, mdlen);
 270     return ret == 0;
 271 }
 272
 273 /*
 274  * Given an input secret |insecret| of length |insecretlen| generate the
 275  * handshake secret. This requires the early secret to already have been
 276  * generated. Returns 1 on success  0 on failure.
 277  */
 278 int tls13_generate_handshake_secret(SSL *s, const unsigned char *insecret,
 279                                 size_t insecretlen)
 280 {
 281     /* Calls SSLfatal() if required */
 282     return tls13_generate_secret(s, ssl_handshake_md(s), s->early_secret,
 283                                  insecret, insecretlen,
 284                                  (unsigned char *)&s->handshake_secret);
 285 }
 286
 287 /*
 288  * Given the handshake secret |prev| of length |prevlen| generate the master
 289  * secret and store its length in |*secret_size|. Returns 1 on success  0 on
 290  * failure.
 291  */
 292 int tls13_generate_master_secret(SSL *s, unsigned char *out,
 293                                  unsigned char *prev, size_t prevlen,
 294                                  size_t *secret_size)
 295 {
 296     const EVP_MD *md = ssl_handshake_md(s);
 297
 298     *secret_size = EVP_MD_size(md);
 299     /* Calls SSLfatal() if required */
 300     return tls13_generate_secret(s, md, prev, NULL, 0, out);
 301 }
 302
 303 /*
 304  * Generates the mac for the Finished message. Returns the length of the MAC or
 305  * 0 on error.
 306  */
 307 size_t tls13_final_finish_mac(SSL *s, const char *str, size_t slen,
 308                              unsigned char *out)
 309 {
 310     const char *mdname = EVP_MD_name(ssl_handshake_md(s));
 311     EVP_MAC *hmac = EVP_MAC_fetch(s->ctx->libctx, "HMAC", s->ctx->propq);
 312     unsigned char hash[EVP_MAX_MD_SIZE];
 313     unsigned char finsecret[EVP_MAX_MD_SIZE];
 314     unsigned char *key = NULL;
 315     size_t hashlen, ret = 0;
 316     EVP_MAC_CTX *ctx = NULL;
 317     OSSL_PARAM params[3], *p = params;
 318
 319     if (hmac == NULL) {
 320         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 321         goto err;
 322     }
 323
 324     /* Safe to cast away const here since we're not "getting" any data */
 325     *p++ = OSSL_PARAM_construct_utf8_string(OSSL_ALG_PARAM_DIGEST,
 326                                             (char *)mdname, 0);
 327     if (s->ctx->propq != NULL)
 328         *p++ = OSSL_PARAM_construct_utf8_string(OSSL_ALG_PARAM_PROPERTIES,
 329                                                 (char *)s->ctx->propq,
 330                                                 0);
 331     *p = OSSL_PARAM_construct_end();
 332
 333     if (!ssl_handshake_hash(s, hash, sizeof(hash), &hashlen)) {
 334         /* SSLfatal() already called */
 335         goto err;
 336     }
 337
 338     if (str == s->method->ssl3_enc->server_finished_label) {
 339         key = s->server_finished_secret;
 340     } else if (SSL_IS_FIRST_HANDSHAKE(s)) {
 341         key = s->client_finished_secret;
 342     } else {
 343         if (!tls13_derive_finishedkey(s, ssl_handshake_md(s),
 344                                       s->client_app_traffic_secret,
 345                                       finsecret, hashlen))
 346             goto err;
 347         key = finsecret;
 348     }
 349
 350     ctx = EVP_MAC_CTX_new(hmac);
 351     if (ctx == NULL
 352             || !EVP_MAC_init(ctx, key, hashlen, params)
 353             || !EVP_MAC_update(ctx, hash, hashlen)
 354                /* outsize as per sizeof(peer_finish_md) */
 355             || !EVP_MAC_final(ctx, out, &hashlen, EVP_MAX_MD_SIZE * 2)) {
 356         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 357         goto err;
 358     }
 359
 360     ret = hashlen;
 361  err:
 362     OPENSSL_cleanse(finsecret, sizeof(finsecret));
 363     EVP_MAC_CTX_free(ctx);
 364     EVP_MAC_free(hmac);
 365     return ret;
 366 }
 367
 368 /*
 369  * There isn't really a key block in TLSv1.3, but we still need this function
 370  * for initialising the cipher and hash. Returns 1 on success or 0 on failure.
 371  */
 372 int tls13_setup_key_block(SSL *s)
 373 {
 374     const EVP_CIPHER *c;
 375     const EVP_MD *hash;
 376
 377     s->session->cipher = s->s3.tmp.new_cipher;
 378     if (!ssl_cipher_get_evp(s->ctx, s->session, &c, &hash, NULL, NULL, NULL,
 379                             0)) {
 380         /* Error is already recorded */
 381         SSLfatal_alert(s, SSL_AD_INTERNAL_ERROR);
 382         return 0;
 383     }
 384
 385     ssl_evp_cipher_free(s->s3.tmp.new_sym_enc);
 386     s->s3.tmp.new_sym_enc = c;
 387     ssl_evp_md_free(s->s3.tmp.new_hash);
 388     s->s3.tmp.new_hash = hash;
 389
 390     return 1;
 391 }
 392
 393 static int derive_secret_key_and_iv(SSL *s, int sending, const EVP_MD *md,
 394                                     const EVP_CIPHER *ciph,
 395                                     const unsigned char *insecret,
 396                                     const unsigned char *hash,
 397                                     const unsigned char *label,
 398                                     size_t labellen, unsigned char *secret,
 399                                     unsigned char *key, unsigned char *iv,
 400                                     EVP_CIPHER_CTX *ciph_ctx)
 401 {
 402     size_t ivlen, keylen, taglen;
 403     int hashleni = EVP_MD_size(md);
 404     size_t hashlen;
 405
 406     /* Ensure cast to size_t is safe */
 407     if (!ossl_assert(hashleni >= 0)) {
 408         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_EVP_LIB);
 409         return 0;
 410     }
 411     hashlen = (size_t)hashleni;
 412
 413     if (!tls13_hkdf_expand(s, md, insecret, label, labellen, hash, hashlen,
 414                            secret, hashlen, 1)) {
 415         /* SSLfatal() already called */
 416         return 0;
 417     }
 418
 419     /* TODO(size_t): convert me */
 420     keylen = EVP_CIPHER_key_length(ciph);
 421     if (EVP_CIPHER_mode(ciph) == EVP_CIPH_CCM_MODE) {
 422         uint32_t algenc;
 423
 424         ivlen = EVP_CCM_TLS_IV_LEN;
 425         if (s->s3.tmp.new_cipher != NULL) {
 426             algenc = s->s3.tmp.new_cipher->algorithm_enc;
 427         } else if (s->session->cipher != NULL) {
 428             /* We've not selected a cipher yet - we must be doing early data */
 429             algenc = s->session->cipher->algorithm_enc;
 430         } else if (s->psksession != NULL && s->psksession->cipher != NULL) {
 431             /* We must be doing early data with out-of-band PSK */
 432             algenc = s->psksession->cipher->algorithm_enc;
 433         } else {
 434             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_EVP_LIB);
 435             return 0;
 436         }
 437         if (algenc & (SSL_AES128CCM8 | SSL_AES256CCM8))
 438             taglen = EVP_CCM8_TLS_TAG_LEN;
 439          else
 440             taglen = EVP_CCM_TLS_TAG_LEN;
 441     } else {
 442         ivlen = EVP_CIPHER_iv_length(ciph);
 443         taglen = 0;
 444     }
 445
 446     if (!tls13_derive_key(s, md, secret, key, keylen)
 447             || !tls13_derive_iv(s, md, secret, iv, ivlen)) {
 448         /* SSLfatal() already called */
 449         return 0;
 450     }
 451
 452     if (EVP_CipherInit_ex(ciph_ctx, ciph, NULL, NULL, NULL, sending) <= 0
 453         || !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
 454         || (taglen != 0 && !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_TAG,
 455                                                 taglen, NULL))
 456         || EVP_CipherInit_ex(ciph_ctx, NULL, NULL, key, NULL, -1) <= 0) {
 457         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_EVP_LIB);
 458         return 0;
 459     }
 460
 461     return 1;
 462 }
 463
 464 int tls13_change_cipher_state(SSL *s, int which)
 465 {
 466 #ifdef CHARSET_EBCDIC
 467   static const unsigned char client_early_traffic[]       = {0x63, 0x20, 0x65, 0x20,       /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
 468   static const unsigned char client_handshake_traffic[]   = {0x63, 0x20, 0x68, 0x73, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
 469   static const unsigned char client_application_traffic[] = {0x63, 0x20, 0x61, 0x70, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
 470   static const unsigned char server_handshake_traffic[]   = {0x73, 0x20, 0x68, 0x73, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
 471   static const unsigned char server_application_traffic[] = {0x73, 0x20, 0x61, 0x70, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
 472   static const unsigned char exporter_master_secret[] = {0x65, 0x78, 0x70, 0x20,                    /* master*/  0x6D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x00};
 473   static const unsigned char resumption_master_secret[] = {0x72, 0x65, 0x73, 0x20,                  /* master*/  0x6D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x00};
 474   static const unsigned char early_exporter_master_secret[] = {0x65, 0x20, 0x65, 0x78, 0x70, 0x20,  /* master*/  0x6D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x00};
 475 #else
 476     static const unsigned char client_early_traffic[] = "c e traffic";
 477     static const unsigned char client_handshake_traffic[] = "c hs traffic";
 478     static const unsigned char client_application_traffic[] = "c ap traffic";
 479     static const unsigned char server_handshake_traffic[] = "s hs traffic";
 480     static const unsigned char server_application_traffic[] = "s ap traffic";
 481     static const unsigned char exporter_master_secret[] = "exp master";
 482     static const unsigned char resumption_master_secret[] = "res master";
 483     static const unsigned char early_exporter_master_secret[] = "e exp master";
 484 #endif
 485     unsigned char *iv;
 486     unsigned char key[EVP_MAX_KEY_LENGTH];
 487     unsigned char secret[EVP_MAX_MD_SIZE];
 488     unsigned char hashval[EVP_MAX_MD_SIZE];
 489     unsigned char *hash = hashval;
 490     unsigned char *insecret;
 491     unsigned char *finsecret = NULL;
 492     const char *log_label = NULL;
 493     EVP_CIPHER_CTX *ciph_ctx;
 494     size_t finsecretlen = 0;
 495     const unsigned char *label;
 496     size_t labellen, hashlen = 0;
 497     int ret = 0;
 498     const EVP_MD *md = NULL;
 499     const EVP_CIPHER *cipher = NULL;
 500 #if !defined(OPENSSL_NO_KTLS) && defined(OPENSSL_KTLS_TLS13)
 501     ktls_crypto_info_t crypto_info;
 502     BIO *bio;
 503 #endif
 504
 505     if (which & SSL3_CC_READ) {
 506         if (s->enc_read_ctx != NULL) {
 507             EVP_CIPHER_CTX_reset(s->enc_read_ctx);
 508         } else {
 509             s->enc_read_ctx = EVP_CIPHER_CTX_new();
 510             if (s->enc_read_ctx == NULL) {
 511                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_MALLOC_FAILURE);
 512                 goto err;
 513             }
 514         }
 515         ciph_ctx = s->enc_read_ctx;
 516         iv = s->read_iv;
 517
 518         RECORD_LAYER_reset_read_sequence(&s->rlayer);
 519     } else {
 520         s->statem.enc_write_state = ENC_WRITE_STATE_INVALID;
 521         if (s->enc_write_ctx != NULL) {
 522             EVP_CIPHER_CTX_reset(s->enc_write_ctx);
 523         } else {
 524             s->enc_write_ctx = EVP_CIPHER_CTX_new();
 525             if (s->enc_write_ctx == NULL) {
 526                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_MALLOC_FAILURE);
 527                 goto err;
 528             }
 529         }
 530         ciph_ctx = s->enc_write_ctx;
 531         iv = s->write_iv;
 532
 533         RECORD_LAYER_reset_write_sequence(&s->rlayer);
 534     }
 535
 536     if (((which & SSL3_CC_CLIENT) && (which & SSL3_CC_WRITE))
 537             || ((which & SSL3_CC_SERVER) && (which & SSL3_CC_READ))) {
 538         if (which & SSL3_CC_EARLY) {
 539             EVP_MD_CTX *mdctx = NULL;
 540             long handlen;
 541             void *hdata;
 542             unsigned int hashlenui;
 543             const SSL_CIPHER *sslcipher = SSL_SESSION_get0_cipher(s->session);
 544
 545             insecret = s->early_secret;
 546             label = client_early_traffic;
 547             labellen = sizeof(client_early_traffic) - 1;
 548             log_label = CLIENT_EARLY_LABEL;
 549
 550             handlen = BIO_get_mem_data(s->s3.handshake_buffer, &hdata);
 551             if (handlen <= 0) {
 552                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_R_BAD_HANDSHAKE_LENGTH);
 553                 goto err;
 554             }
 555
 556             if (s->early_data_state == SSL_EARLY_DATA_CONNECTING
 557                     && s->max_early_data > 0
 558                     && s->session->ext.max_early_data == 0) {
 559                 /*
 560                  * If we are attempting to send early data, and we've decided to
 561                  * actually do it but max_early_data in s->session is 0 then we
 562                  * must be using an external PSK.
 563                  */
 564                 if (!ossl_assert(s->psksession != NULL
 565                         && s->max_early_data ==
 566                            s->psksession->ext.max_early_data)) {
 567                     SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 568                     goto err;
 569                 }
 570                 sslcipher = SSL_SESSION_get0_cipher(s->psksession);
 571             }
 572             if (sslcipher == NULL) {
 573                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_R_BAD_PSK);
 574                 goto err;
 575             }
 576
 577             /*
 578              * We need to calculate the handshake digest using the digest from
 579              * the session. We haven't yet selected our ciphersuite so we can't
 580              * use ssl_handshake_md().
 581              */
 582             mdctx = EVP_MD_CTX_new();
 583             if (mdctx == NULL) {
 584                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_MALLOC_FAILURE);
 585                 goto err;
 586             }
 587
 588             /*
 589              * This ups the ref count on cipher so we better make sure we free
 590              * it again
 591              */
 592             if (!ssl_cipher_get_evp_cipher(s->ctx, sslcipher, &cipher)) {
 593                 /* Error is already recorded */
 594                 SSLfatal_alert(s, SSL_AD_INTERNAL_ERROR);
 595                 EVP_MD_CTX_free(mdctx);
 596                 goto err;
 597             }
 598
 599             md = ssl_md(s->ctx, sslcipher->algorithm2);
 600             if (md == NULL || !EVP_DigestInit_ex(mdctx, md, NULL)
 601                     || !EVP_DigestUpdate(mdctx, hdata, handlen)
 602                     || !EVP_DigestFinal_ex(mdctx, hashval, &hashlenui)) {
 603                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 604                 EVP_MD_CTX_free(mdctx);
 605                 goto err;
 606             }
 607             hashlen = hashlenui;
 608             EVP_MD_CTX_free(mdctx);
 609
 610             if (!tls13_hkdf_expand(s, md, insecret,
 611                                    early_exporter_master_secret,
 612                                    sizeof(early_exporter_master_secret) - 1,
 613                                    hashval, hashlen,
 614                                    s->early_exporter_master_secret, hashlen,
 615                                    1)) {
 616                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 617                 goto err;
 618             }
 619
 620             if (!ssl_log_secret(s, EARLY_EXPORTER_SECRET_LABEL,
 621                                 s->early_exporter_master_secret, hashlen)) {
 622                 /* SSLfatal() already called */
 623                 goto err;
 624             }
 625         } else if (which & SSL3_CC_HANDSHAKE) {
 626             insecret = s->handshake_secret;
 627             finsecret = s->client_finished_secret;
 628             finsecretlen = EVP_MD_size(ssl_handshake_md(s));
 629             label = client_handshake_traffic;
 630             labellen = sizeof(client_handshake_traffic) - 1;
 631             log_label = CLIENT_HANDSHAKE_LABEL;
 632             /*
 633              * The handshake hash used for the server read/client write handshake
 634              * traffic secret is the same as the hash for the server
 635              * write/client read handshake traffic secret. However, if we
 636              * processed early data then we delay changing the server
 637              * read/client write cipher state until later, and the handshake
 638              * hashes have moved on. Therefore we use the value saved earlier
 639              * when we did the server write/client read change cipher state.
 640              */
 641             hash = s->handshake_traffic_hash;
 642         } else {
 643             insecret = s->master_secret;
 644             label = client_application_traffic;
 645             labellen = sizeof(client_application_traffic) - 1;
 646             log_label = CLIENT_APPLICATION_LABEL;
 647             /*
 648              * For this we only use the handshake hashes up until the server
 649              * Finished hash. We do not include the client's Finished, which is
 650              * what ssl_handshake_hash() would give us. Instead we use the
 651              * previously saved value.
 652              */
 653             hash = s->server_finished_hash;
 654         }
 655     } else {
 656         /* Early data never applies to client-read/server-write */
 657         if (which & SSL3_CC_HANDSHAKE) {
 658             insecret = s->handshake_secret;
 659             finsecret = s->server_finished_secret;
 660             finsecretlen = EVP_MD_size(ssl_handshake_md(s));
 661             label = server_handshake_traffic;
 662             labellen = sizeof(server_handshake_traffic) - 1;
 663             log_label = SERVER_HANDSHAKE_LABEL;
 664         } else {
 665             insecret = s->master_secret;
 666             label = server_application_traffic;
 667             labellen = sizeof(server_application_traffic) - 1;
 668             log_label = SERVER_APPLICATION_LABEL;
 669         }
 670     }
 671
 672     if (!(which & SSL3_CC_EARLY)) {
 673         md = ssl_handshake_md(s);
 674         cipher = s->s3.tmp.new_sym_enc;
 675         if (!ssl3_digest_cached_records(s, 1)
 676                 || !ssl_handshake_hash(s, hashval, sizeof(hashval), &hashlen)) {
 677             /* SSLfatal() already called */;
 678             goto err;
 679         }
 680     }
 681
 682     /*
 683      * Save the hash of handshakes up to now for use when we calculate the
 684      * client application traffic secret
 685      */
 686     if (label == server_application_traffic)
 687         memcpy(s->server_finished_hash, hashval, hashlen);
 688
 689     if (label == server_handshake_traffic)
 690         memcpy(s->handshake_traffic_hash, hashval, hashlen);
 691
 692     if (label == client_application_traffic) {
 693         /*
 694          * We also create the resumption master secret, but this time use the
 695          * hash for the whole handshake including the Client Finished
 696          */
 697         if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
 698                                resumption_master_secret,
 699                                sizeof(resumption_master_secret) - 1,
 700                                hashval, hashlen, s->resumption_master_secret,
 701                                hashlen, 1)) {
 702             /* SSLfatal() already called */
 703             goto err;
 704         }
 705     }
 706
 707     /* check whether cipher is known */
 708     if(!ossl_assert(cipher != NULL))
 709         goto err;
 710
 711     if (!derive_secret_key_and_iv(s, which & SSL3_CC_WRITE, md, cipher,
 712                                   insecret, hash, label, labellen, secret, key,
 713                                   iv, ciph_ctx)) {
 714         /* SSLfatal() already called */
 715         goto err;
 716     }
 717
 718     if (label == server_application_traffic) {
 719         memcpy(s->server_app_traffic_secret, secret, hashlen);
 720         /* Now we create the exporter master secret */
 721         if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
 722                                exporter_master_secret,
 723                                sizeof(exporter_master_secret) - 1,
 724                                hash, hashlen, s->exporter_master_secret,
 725                                hashlen, 1)) {
 726             /* SSLfatal() already called */
 727             goto err;
 728         }
 729
 730         if (!ssl_log_secret(s, EXPORTER_SECRET_LABEL, s->exporter_master_secret,
 731                             hashlen)) {
 732             /* SSLfatal() already called */
 733             goto err;
 734         }
 735     } else if (label == client_application_traffic)
 736         memcpy(s->client_app_traffic_secret, secret, hashlen);
 737
 738     if (!ssl_log_secret(s, log_label, secret, hashlen)) {
 739         /* SSLfatal() already called */
 740         goto err;
 741     }
 742
 743     if (finsecret != NULL
 744             && !tls13_derive_finishedkey(s, ssl_handshake_md(s), secret,
 745                                          finsecret, finsecretlen)) {
 746         /* SSLfatal() already called */
 747         goto err;
 748     }
 749
 750     if (!s->server && label == client_early_traffic)
 751         s->statem.enc_write_state = ENC_WRITE_STATE_WRITE_PLAIN_ALERTS;
 752     else
 753         s->statem.enc_write_state = ENC_WRITE_STATE_VALID;
 754 #ifndef OPENSSL_NO_KTLS
 755 # if defined(OPENSSL_KTLS_TLS13)
 756     if (!(which & SSL3_CC_WRITE) || !(which & SSL3_CC_APPLICATION)
 757         || ((which & SSL3_CC_WRITE) && (s->mode & SSL_MODE_NO_KTLS_TX)))
 758         goto skip_ktls;
 759
 760     /* ktls supports only the maximum fragment size */
 761     if (ssl_get_max_send_fragment(s) != SSL3_RT_MAX_PLAIN_LENGTH)
 762         goto skip_ktls;
 763
 764     /* ktls does not support record padding */
 765     if (s->record_padding_cb != NULL)
 766         goto skip_ktls;
 767
 768     /* check that cipher is supported */
 769     if (!ktls_check_supported_cipher(s, cipher, ciph_ctx))
 770         goto skip_ktls;
 771
 772     bio = s->wbio;
 773
 774     if (!ossl_assert(bio != NULL)) {
 775         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 776         goto err;
 777     }
 778
 779     /* All future data will get encrypted by ktls. Flush the BIO or skip ktls */
 780     if (BIO_flush(bio) <= 0)
 781         goto skip_ktls;
 782
 783     /* configure kernel crypto structure */
 784     if (!ktls_configure_crypto(s, cipher, ciph_ctx,
 785                                RECORD_LAYER_get_write_sequence(&s->rlayer),
 786                                &crypto_info, NULL, iv, key, NULL, 0))
 787         goto skip_ktls;
 788
 789     /* ktls works with user provided buffers directly */
 790     if (BIO_set_ktls(bio, &crypto_info, which & SSL3_CC_WRITE))
 791         ssl3_release_write_buffer(s);
 792 skip_ktls:
 793 # endif
 794 #endif
 795     ret = 1;
 796  err:
 797     if ((which & SSL3_CC_EARLY) != 0) {
 798         /* We up-refed this so now we need to down ref */
 799         ssl_evp_cipher_free(cipher);
 800     }
 801     OPENSSL_cleanse(key, sizeof(key));
 802     OPENSSL_cleanse(secret, sizeof(secret));
 803     return ret;
 804 }
 805
 806 int tls13_update_key(SSL *s, int sending)
 807 {
 808 #ifdef CHARSET_EBCDIC
 809   static const unsigned char application_traffic[] = { 0x74, 0x72 ,0x61 ,0x66 ,0x66 ,0x69 ,0x63 ,0x20 ,0x75 ,0x70 ,0x64, 0x00};
 810 #else
 811   static const unsigned char application_traffic[] = "traffic upd";
 812 #endif
 813     const EVP_MD *md = ssl_handshake_md(s);
 814     size_t hashlen = EVP_MD_size(md);
 815     unsigned char key[EVP_MAX_KEY_LENGTH];
 816     unsigned char *insecret, *iv;
 817     unsigned char secret[EVP_MAX_MD_SIZE];
 818     EVP_CIPHER_CTX *ciph_ctx;
 819     int ret = 0;
 820
 821     if (s->server == sending)
 822         insecret = s->server_app_traffic_secret;
 823     else
 824         insecret = s->client_app_traffic_secret;
 825
 826     if (sending) {
 827         s->statem.enc_write_state = ENC_WRITE_STATE_INVALID;
 828         iv = s->write_iv;
 829         ciph_ctx = s->enc_write_ctx;
 830         RECORD_LAYER_reset_write_sequence(&s->rlayer);
 831     } else {
 832         iv = s->read_iv;
 833         ciph_ctx = s->enc_read_ctx;
 834         RECORD_LAYER_reset_read_sequence(&s->rlayer);
 835     }
 836
 837     if (!derive_secret_key_and_iv(s, sending, ssl_handshake_md(s),
 838                                   s->s3.tmp.new_sym_enc, insecret, NULL,
 839                                   application_traffic,
 840                                   sizeof(application_traffic) - 1, secret, key,
 841                                   iv, ciph_ctx)) {
 842         /* SSLfatal() already called */
 843         goto err;
 844     }
 845
 846     memcpy(insecret, secret, hashlen);
 847
 848     s->statem.enc_write_state = ENC_WRITE_STATE_VALID;
 849     ret = 1;
 850  err:
 851     OPENSSL_cleanse(key, sizeof(key));
 852     OPENSSL_cleanse(secret, sizeof(secret));
 853     return ret;
 854 }
 855
 856 int tls13_alert_code(int code)
 857 {
 858     /* There are 2 additional alerts in TLSv1.3 compared to TLSv1.2 */
 859     if (code == SSL_AD_MISSING_EXTENSION || code == SSL_AD_CERTIFICATE_REQUIRED)
 860         return code;
 861
 862     return tls1_alert_code(code);
 863 }
 864
 865 int tls13_export_keying_material(SSL *s, unsigned char *out, size_t olen,
 866                                  const char *label, size_t llen,
 867                                  const unsigned char *context,
 868                                  size_t contextlen, int use_context)
 869 {
 870     unsigned char exportsecret[EVP_MAX_MD_SIZE];
 871 #ifdef CHARSET_EBCDIC
 872     static const unsigned char exporterlabel[] = {0x65, 0x78, 0x70, 0x6F, 0x72, 0x74, 0x65, 0x72, 0x00};
 873 #else
 874     static const unsigned char exporterlabel[] = "exporter";
 875 #endif
 876     unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE];
 877     const EVP_MD *md = ssl_handshake_md(s);
 878     EVP_MD_CTX *ctx = EVP_MD_CTX_new();
 879     unsigned int hashsize, datalen;
 880     int ret = 0;
 881
 882     if (ctx == NULL || !ossl_statem_export_allowed(s))
 883         goto err;
 884
 885     if (!use_context)
 886         contextlen = 0;
 887
 888     if (EVP_DigestInit_ex(ctx, md, NULL) <= 0
 889             || EVP_DigestUpdate(ctx, context, contextlen) <= 0
 890             || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0
 891             || EVP_DigestInit_ex(ctx, md, NULL) <= 0
 892             || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0
 893             || !tls13_hkdf_expand(s, md, s->exporter_master_secret,
 894                                   (const unsigned char *)label, llen,
 895                                   data, datalen, exportsecret, hashsize, 0)
 896             || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel,
 897                                   sizeof(exporterlabel) - 1, hash, hashsize,
 898                                   out, olen, 0))
 899         goto err;
 900
 901     ret = 1;
 902  err:
 903     EVP_MD_CTX_free(ctx);
 904     return ret;
 905 }
 906
 907 int tls13_export_keying_material_early(SSL *s, unsigned char *out, size_t olen,
 908                                        const char *label, size_t llen,
 909                                        const unsigned char *context,
 910                                        size_t contextlen)
 911 {
 912 #ifdef CHARSET_EBCDIC
 913   static const unsigned char exporterlabel[] = {0x65, 0x78, 0x70, 0x6F, 0x72, 0x74, 0x65, 0x72, 0x00};
 914 #else
 915   static const unsigned char exporterlabel[] = "exporter";
 916 #endif
 917     unsigned char exportsecret[EVP_MAX_MD_SIZE];
 918     unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE];
 919     const EVP_MD *md;
 920     EVP_MD_CTX *ctx = EVP_MD_CTX_new();
 921     unsigned int hashsize, datalen;
 922     int ret = 0;
 923     const SSL_CIPHER *sslcipher;
 924
 925     if (ctx == NULL || !ossl_statem_export_early_allowed(s))
 926         goto err;
 927
 928     if (!s->server && s->max_early_data > 0
 929             && s->session->ext.max_early_data == 0)
 930         sslcipher = SSL_SESSION_get0_cipher(s->psksession);
 931     else
 932         sslcipher = SSL_SESSION_get0_cipher(s->session);
 933
 934     md = ssl_md(s->ctx, sslcipher->algorithm2);
 935
 936     /*
 937      * Calculate the hash value and store it in |data|. The reason why
 938      * the empty string is used is that the definition of TLS-Exporter
 939      * is like so:
 940      *
 941      * TLS-Exporter(label, context_value, key_length) =
 942      *     HKDF-Expand-Label(Derive-Secret(Secret, label, ""),
 943      *                       "exporter", Hash(context_value), key_length)
 944      *
 945      * Derive-Secret(Secret, Label, Messages) =
 946      *       HKDF-Expand-Label(Secret, Label,
 947      *                         Transcript-Hash(Messages), Hash.length)
 948      *
 949      * Here Transcript-Hash is the cipher suite hash algorithm.
 950      */
 951     if (EVP_DigestInit_ex(ctx, md, NULL) <= 0
 952             || EVP_DigestUpdate(ctx, context, contextlen) <= 0
 953             || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0
 954             || EVP_DigestInit_ex(ctx, md, NULL) <= 0
 955             || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0
 956             || !tls13_hkdf_expand(s, md, s->early_exporter_master_secret,
 957                                   (const unsigned char *)label, llen,
 958                                   data, datalen, exportsecret, hashsize, 0)
 959             || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel,
 960                                   sizeof(exporterlabel) - 1, hash, hashsize,
 961                                   out, olen, 0))
 962         goto err;
 963
 964     ret = 1;
 965  err:
 966     EVP_MD_CTX_free(ctx);
 967     return ret;
 968 }