ssl/tls13_enc.c

   1 /*
   2  * Copyright 2016-2023 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 /* ASCII: "tls13 ", in hex for EBCDIC compatibility */
  22 static const unsigned char label_prefix[] = "\x74\x6C\x73\x31\x33\x20";
  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  * If |raise_error| is set, ERR_raise is called on failure.
  31  */
  32 int tls13_hkdf_expand_ex(OSSL_LIB_CTX *libctx, const char *propq,
  33                          const EVP_MD *md,
  34                          const unsigned char *secret,
  35                          const unsigned char *label, size_t labellen,
  36                          const unsigned char *data, size_t datalen,
  37                          unsigned char *out, size_t outlen, int raise_error)
  38 {
  39     EVP_KDF *kdf = EVP_KDF_fetch(libctx, OSSL_KDF_NAME_TLS1_3_KDF, propq);
  40     EVP_KDF_CTX *kctx;
  41     OSSL_PARAM params[7], *p = params;
  42     int mode = EVP_PKEY_HKDEF_MODE_EXPAND_ONLY;
  43     const char *mdname = EVP_MD_get0_name(md);
  44     int ret;
  45     size_t hashlen;
  46
  47     kctx = EVP_KDF_CTX_new(kdf);
  48     EVP_KDF_free(kdf);
  49     if (kctx == NULL)
  50         return 0;
  51
  52     if (labellen > TLS13_MAX_LABEL_LEN) {
  53         if (raise_error)
  54             /*
  55              * Probably we have been called from SSL_export_keying_material(),
  56              * or SSL_export_keying_material_early().
  57              */
  58             ERR_raise(ERR_LIB_SSL, SSL_R_TLS_ILLEGAL_EXPORTER_LABEL);
  59
  60         EVP_KDF_CTX_free(kctx);
  61         return 0;
  62     }
  63
  64     if ((ret = EVP_MD_get_size(md)) <= 0) {
  65         EVP_KDF_CTX_free(kctx);
  66         if (raise_error)
  67             ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR);
  68         return 0;
  69     }
  70     hashlen = (size_t)ret;
  71
  72     *p++ = OSSL_PARAM_construct_int(OSSL_KDF_PARAM_MODE, &mode);
  73     *p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
  74                                             (char *)mdname, 0);
  75     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY,
  76                                              (unsigned char *)secret, hashlen);
  77     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_PREFIX,
  78                                              (unsigned char *)label_prefix,
  79                                              sizeof(label_prefix) - 1);
  80     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_LABEL,
  81                                              (unsigned char *)label, labellen);
  82     if (data != NULL)
  83         *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_DATA,
  84                                                  (unsigned char *)data,
  85                                                  datalen);
  86     *p++ = OSSL_PARAM_construct_end();
  87
  88     ret = EVP_KDF_derive(kctx, out, outlen, params) <= 0;
  89     EVP_KDF_CTX_free(kctx);
  90
  91     if (ret != 0) {
  92         if (raise_error)
  93             ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR);
  94     }
  95
  96     return ret == 0;
  97 }
  98
  99 int tls13_hkdf_expand(SSL_CONNECTION *s, const EVP_MD *md,
 100                       const unsigned char *secret,
 101                       const unsigned char *label, size_t labellen,
 102                       const unsigned char *data, size_t datalen,
 103                       unsigned char *out, size_t outlen, int fatal)
 104 {
 105     int ret;
 106     SSL_CTX *sctx = SSL_CONNECTION_GET_CTX(s);
 107
 108     ret = tls13_hkdf_expand_ex(sctx->libctx, sctx->propq, md,
 109                                secret, label, labellen, data, datalen,
 110                                out, outlen, !fatal);
 111     if (ret == 0 && fatal)
 112         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 113
 114     return ret;
 115 }
 116
 117 /*
 118  * Given a |secret| generate a |key| of length |keylen| bytes. Returns 1 on
 119  * success  0 on failure.
 120  */
 121 int tls13_derive_key(SSL_CONNECTION *s, const EVP_MD *md,
 122                      const unsigned char *secret,
 123                      unsigned char *key, size_t keylen)
 124 {
 125     /* ASCII: "key", in hex for EBCDIC compatibility */
 126     static const unsigned char keylabel[] = "\x6B\x65\x79";
 127
 128     return tls13_hkdf_expand(s, md, secret, keylabel, sizeof(keylabel) - 1,
 129                              NULL, 0, key, keylen, 1);
 130 }
 131
 132 /*
 133  * Given a |secret| generate an |iv| of length |ivlen| bytes. Returns 1 on
 134  * success  0 on failure.
 135  */
 136 int tls13_derive_iv(SSL_CONNECTION *s, const EVP_MD *md,
 137                     const unsigned char *secret,
 138                     unsigned char *iv, size_t ivlen)
 139 {
 140     /* ASCII: "iv", in hex for EBCDIC compatibility */
 141     static const unsigned char ivlabel[] = "\x69\x76";
 142
 143     return tls13_hkdf_expand(s, md, secret, ivlabel, sizeof(ivlabel) - 1,
 144                              NULL, 0, iv, ivlen, 1);
 145 }
 146
 147 int tls13_derive_finishedkey(SSL_CONNECTION *s, const EVP_MD *md,
 148                              const unsigned char *secret,
 149                              unsigned char *fin, size_t finlen)
 150 {
 151     /* ASCII: "finished", in hex for EBCDIC compatibility */
 152     static const unsigned char finishedlabel[] = "\x66\x69\x6E\x69\x73\x68\x65\x64";
 153
 154     return tls13_hkdf_expand(s, md, secret, finishedlabel,
 155                              sizeof(finishedlabel) - 1, NULL, 0, fin, finlen, 1);
 156 }
 157
 158 /*
 159  * Given the previous secret |prevsecret| and a new input secret |insecret| of
 160  * length |insecretlen|, generate a new secret and store it in the location
 161  * pointed to by |outsecret|. Returns 1 on success  0 on failure.
 162  */
 163 int tls13_generate_secret(SSL_CONNECTION *s, const EVP_MD *md,
 164                           const unsigned char *prevsecret,
 165                           const unsigned char *insecret,
 166                           size_t insecretlen,
 167                           unsigned char *outsecret)
 168 {
 169     size_t mdlen;
 170     int mdleni;
 171     int ret;
 172     EVP_KDF *kdf;
 173     EVP_KDF_CTX *kctx;
 174     OSSL_PARAM params[7], *p = params;
 175     int mode = EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY;
 176     const char *mdname = EVP_MD_get0_name(md);
 177     /* ASCII: "derived", in hex for EBCDIC compatibility */
 178     static const char derived_secret_label[] = "\x64\x65\x72\x69\x76\x65\x64";
 179     SSL_CTX *sctx = SSL_CONNECTION_GET_CTX(s);
 180
 181     kdf = EVP_KDF_fetch(sctx->libctx, OSSL_KDF_NAME_TLS1_3_KDF, sctx->propq);
 182     kctx = EVP_KDF_CTX_new(kdf);
 183     EVP_KDF_free(kdf);
 184     if (kctx == NULL) {
 185         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 186         return 0;
 187     }
 188
 189     mdleni = EVP_MD_get_size(md);
 190     /* Ensure cast to size_t is safe */
 191     if (!ossl_assert(mdleni >= 0)) {
 192         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 193         EVP_KDF_CTX_free(kctx);
 194         return 0;
 195     }
 196     mdlen = (size_t)mdleni;
 197
 198     *p++ = OSSL_PARAM_construct_int(OSSL_KDF_PARAM_MODE, &mode);
 199     *p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
 200                                             (char *)mdname, 0);
 201     if (insecret != NULL)
 202         *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY,
 203                                                  (unsigned char *)insecret,
 204                                                  insecretlen);
 205     if (prevsecret != NULL)
 206         *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SALT,
 207                                                  (unsigned char *)prevsecret, mdlen);
 208     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_PREFIX,
 209                                              (unsigned char *)label_prefix,
 210                                              sizeof(label_prefix) - 1);
 211     *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_LABEL,
 212                                              (unsigned char *)derived_secret_label,
 213                                              sizeof(derived_secret_label) - 1);
 214     *p++ = OSSL_PARAM_construct_end();
 215
 216     ret = EVP_KDF_derive(kctx, outsecret, mdlen, params) <= 0;
 217
 218     if (ret != 0)
 219         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 220
 221     EVP_KDF_CTX_free(kctx);
 222     return ret == 0;
 223 }
 224
 225 /*
 226  * Given an input secret |insecret| of length |insecretlen| generate the
 227  * handshake secret. This requires the early secret to already have been
 228  * generated. Returns 1 on success  0 on failure.
 229  */
 230 int tls13_generate_handshake_secret(SSL_CONNECTION *s,
 231                                     const unsigned char *insecret,
 232                                     size_t insecretlen)
 233 {
 234     /* Calls SSLfatal() if required */
 235     return tls13_generate_secret(s, ssl_handshake_md(s), s->early_secret,
 236                                  insecret, insecretlen,
 237                                  (unsigned char *)&s->handshake_secret);
 238 }
 239
 240 /*
 241  * Given the handshake secret |prev| of length |prevlen| generate the master
 242  * secret and store its length in |*secret_size|. Returns 1 on success  0 on
 243  * failure.
 244  */
 245 int tls13_generate_master_secret(SSL_CONNECTION *s, unsigned char *out,
 246                                  unsigned char *prev, size_t prevlen,
 247                                  size_t *secret_size)
 248 {
 249     const EVP_MD *md = ssl_handshake_md(s);
 250     int md_size;
 251
 252     md_size = EVP_MD_get_size(md);
 253     if (md_size <= 0) {
 254         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 255         return 0;
 256     }
 257     *secret_size = (size_t)md_size;
 258     /* Calls SSLfatal() if required */
 259     return tls13_generate_secret(s, md, prev, NULL, 0, out);
 260 }
 261
 262 /*
 263  * Generates the mac for the Finished message. Returns the length of the MAC or
 264  * 0 on error.
 265  */
 266 size_t tls13_final_finish_mac(SSL_CONNECTION *s, const char *str, size_t slen,
 267                              unsigned char *out)
 268 {
 269     const EVP_MD *md = ssl_handshake_md(s);
 270     const char *mdname = EVP_MD_get0_name(md);
 271     unsigned char hash[EVP_MAX_MD_SIZE];
 272     unsigned char finsecret[EVP_MAX_MD_SIZE];
 273     unsigned char *key = NULL;
 274     size_t len = 0, hashlen;
 275     OSSL_PARAM params[2], *p = params;
 276     SSL_CTX *sctx = SSL_CONNECTION_GET_CTX(s);
 277
 278     if (md == NULL)
 279         return 0;
 280
 281     /* Safe to cast away const here since we're not "getting" any data */
 282     if (sctx->propq != NULL)
 283         *p++ = OSSL_PARAM_construct_utf8_string(OSSL_ALG_PARAM_PROPERTIES,
 284                                                 (char *)sctx->propq,
 285                                                 0);
 286     *p = OSSL_PARAM_construct_end();
 287
 288     if (!ssl_handshake_hash(s, hash, sizeof(hash), &hashlen)) {
 289         /* SSLfatal() already called */
 290         goto err;
 291     }
 292
 293     if (str == SSL_CONNECTION_GET_SSL(s)->method->ssl3_enc->server_finished_label) {
 294         key = s->server_finished_secret;
 295     } else if (SSL_IS_FIRST_HANDSHAKE(s)) {
 296         key = s->client_finished_secret;
 297     } else {
 298         if (!tls13_derive_finishedkey(s, md,
 299                                       s->client_app_traffic_secret,
 300                                       finsecret, hashlen))
 301             goto err;
 302         key = finsecret;
 303     }
 304
 305     if (!EVP_Q_mac(sctx->libctx, "HMAC", sctx->propq, mdname,
 306                    params, key, hashlen, hash, hashlen,
 307                    /* outsize as per sizeof(peer_finish_md) */
 308                    out, EVP_MAX_MD_SIZE * 2, &len)) {
 309         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 310         goto err;
 311     }
 312
 313  err:
 314     OPENSSL_cleanse(finsecret, sizeof(finsecret));
 315     return len;
 316 }
 317
 318 /*
 319  * There isn't really a key block in TLSv1.3, but we still need this function
 320  * for initialising the cipher and hash. Returns 1 on success or 0 on failure.
 321  */
 322 int tls13_setup_key_block(SSL_CONNECTION *s)
 323 {
 324     const EVP_CIPHER *c;
 325     const EVP_MD *hash;
 326     int mac_type = NID_undef;
 327     size_t mac_secret_size = 0;
 328
 329     s->session->cipher = s->s3.tmp.new_cipher;
 330     if (!ssl_cipher_get_evp(SSL_CONNECTION_GET_CTX(s), s->session, &c, &hash,
 331                             &mac_type, &mac_secret_size, NULL, 0)) {
 332         /* Error is already recorded */
 333         SSLfatal_alert(s, SSL_AD_INTERNAL_ERROR);
 334         return 0;
 335     }
 336
 337     ssl_evp_cipher_free(s->s3.tmp.new_sym_enc);
 338     s->s3.tmp.new_sym_enc = c;
 339     ssl_evp_md_free(s->s3.tmp.new_hash);
 340     s->s3.tmp.new_hash = hash;
 341     s->s3.tmp.new_mac_pkey_type = mac_type;
 342     s->s3.tmp.new_mac_secret_size = mac_secret_size;
 343
 344     return 1;
 345 }
 346
 347 static int derive_secret_key_and_iv(SSL_CONNECTION *s, const EVP_MD *md,
 348                                     const EVP_CIPHER *ciph,
 349                                     int mac_type,
 350                                     const EVP_MD *mac_md,
 351                                     const unsigned char *insecret,
 352                                     const unsigned char *hash,
 353                                     const unsigned char *label,
 354                                     size_t labellen, unsigned char *secret,
 355                                     unsigned char *key, size_t *keylen,
 356                                     unsigned char **iv, size_t *ivlen,
 357                                     size_t *taglen)
 358 {
 359     int hashleni = EVP_MD_get_size(md);
 360     size_t hashlen;
 361     int mode, mac_mdleni;
 362
 363     /* Ensure cast to size_t is safe */
 364     if (!ossl_assert(hashleni >= 0)) {
 365         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_EVP_LIB);
 366         return 0;
 367     }
 368     hashlen = (size_t)hashleni;
 369
 370     if (!tls13_hkdf_expand(s, md, insecret, label, labellen, hash, hashlen,
 371                            secret, hashlen, 1)) {
 372         /* SSLfatal() already called */
 373         return 0;
 374     }
 375
 376     /* if ciph is NULL cipher, then use new_hash to calculate keylen */
 377     if (EVP_CIPHER_is_a(ciph, "NULL")
 378         && mac_md != NULL
 379         && mac_type == NID_hmac) {
 380         mac_mdleni = EVP_MD_get_size(mac_md);
 381
 382         if (mac_mdleni < 0) {
 383             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 384             return 0;
 385         }
 386         *ivlen = *taglen = (size_t)mac_mdleni;
 387         *keylen = s->s3.tmp.new_mac_secret_size;
 388     } else {
 389
 390         *keylen = EVP_CIPHER_get_key_length(ciph);
 391
 392         mode = EVP_CIPHER_get_mode(ciph);
 393         if (mode == EVP_CIPH_CCM_MODE) {
 394             uint32_t algenc;
 395
 396             *ivlen = EVP_CCM_TLS_IV_LEN;
 397             if (s->s3.tmp.new_cipher != NULL) {
 398                 algenc = s->s3.tmp.new_cipher->algorithm_enc;
 399             } else if (s->session->cipher != NULL) {
 400                 /* We've not selected a cipher yet - we must be doing early data */
 401                 algenc = s->session->cipher->algorithm_enc;
 402             } else if (s->psksession != NULL && s->psksession->cipher != NULL) {
 403                 /* We must be doing early data with out-of-band PSK */
 404                 algenc = s->psksession->cipher->algorithm_enc;
 405             } else {
 406                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_EVP_LIB);
 407                 return 0;
 408             }
 409             if (algenc & (SSL_AES128CCM8 | SSL_AES256CCM8))
 410                 *taglen = EVP_CCM8_TLS_TAG_LEN;
 411             else
 412                 *taglen = EVP_CCM_TLS_TAG_LEN;
 413         } else {
 414             int iivlen;
 415
 416             if (mode == EVP_CIPH_GCM_MODE) {
 417                 *taglen = EVP_GCM_TLS_TAG_LEN;
 418             } else {
 419                 /* CHACHA20P-POLY1305 */
 420                 *taglen = EVP_CHACHAPOLY_TLS_TAG_LEN;
 421             }
 422             iivlen = EVP_CIPHER_get_iv_length(ciph);
 423             if (iivlen < 0) {
 424                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_EVP_LIB);
 425                 return 0;
 426             }
 427             *ivlen = iivlen;
 428         }
 429     }
 430
 431     if (*ivlen > EVP_MAX_IV_LENGTH) {
 432         *iv = OPENSSL_malloc(*ivlen);
 433         if (*iv == NULL) {
 434             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_MALLOC_FAILURE);
 435             return 0;
 436         }
 437     }
 438
 439     if (!tls13_derive_key(s, md, secret, key, *keylen)
 440             || !tls13_derive_iv(s, md, secret, *iv, *ivlen)) {
 441         /* SSLfatal() already called */
 442         return 0;
 443     }
 444
 445     return 1;
 446 }
 447
 448 int tls13_change_cipher_state(SSL_CONNECTION *s, int which)
 449 {
 450     /* ASCII: "c e traffic", in hex for EBCDIC compatibility */
 451     static const unsigned char client_early_traffic[] = "\x63\x20\x65\x20\x74\x72\x61\x66\x66\x69\x63";
 452     /* ASCII: "c hs traffic", in hex for EBCDIC compatibility */
 453     static const unsigned char client_handshake_traffic[] = "\x63\x20\x68\x73\x20\x74\x72\x61\x66\x66\x69\x63";
 454     /* ASCII: "c ap traffic", in hex for EBCDIC compatibility */
 455     static const unsigned char client_application_traffic[] = "\x63\x20\x61\x70\x20\x74\x72\x61\x66\x66\x69\x63";
 456     /* ASCII: "s hs traffic", in hex for EBCDIC compatibility */
 457     static const unsigned char server_handshake_traffic[] = "\x73\x20\x68\x73\x20\x74\x72\x61\x66\x66\x69\x63";
 458     /* ASCII: "s ap traffic", in hex for EBCDIC compatibility */
 459     static const unsigned char server_application_traffic[] = "\x73\x20\x61\x70\x20\x74\x72\x61\x66\x66\x69\x63";
 460     /* ASCII: "exp master", in hex for EBCDIC compatibility */
 461     static const unsigned char exporter_master_secret[] = "\x65\x78\x70\x20\x6D\x61\x73\x74\x65\x72";
 462     /* ASCII: "res master", in hex for EBCDIC compatibility */
 463     static const unsigned char resumption_master_secret[] = "\x72\x65\x73\x20\x6D\x61\x73\x74\x65\x72";
 464     /* ASCII: "e exp master", in hex for EBCDIC compatibility */
 465     static const unsigned char early_exporter_master_secret[] = "\x65\x20\x65\x78\x70\x20\x6D\x61\x73\x74\x65\x72";
 466     unsigned char iv_intern[EVP_MAX_IV_LENGTH];
 467     unsigned char *iv = iv_intern;
 468     unsigned char key[EVP_MAX_KEY_LENGTH];
 469     unsigned char secret[EVP_MAX_MD_SIZE];
 470     unsigned char hashval[EVP_MAX_MD_SIZE];
 471     unsigned char *hash = hashval;
 472     unsigned char *insecret;
 473     unsigned char *finsecret = NULL;
 474     const char *log_label = NULL;
 475     int finsecretlen = 0;
 476     const unsigned char *label;
 477     size_t labellen, hashlen = 0;
 478     int ret = 0;
 479     const EVP_MD *md = NULL, *mac_md = NULL;
 480     const EVP_CIPHER *cipher = NULL;
 481     int mac_pkey_type = NID_undef;
 482     SSL_CTX *sctx = SSL_CONNECTION_GET_CTX(s);
 483     size_t keylen, ivlen = EVP_MAX_IV_LENGTH, taglen;
 484     int level;
 485     int direction = (which & SSL3_CC_READ) != 0 ? OSSL_RECORD_DIRECTION_READ
 486                                                 : OSSL_RECORD_DIRECTION_WRITE;
 487
 488     if (((which & SSL3_CC_CLIENT) && (which & SSL3_CC_WRITE))
 489             || ((which & SSL3_CC_SERVER) && (which & SSL3_CC_READ))) {
 490         if ((which & SSL3_CC_EARLY) != 0) {
 491             EVP_MD_CTX *mdctx = NULL;
 492             long handlen;
 493             void *hdata;
 494             unsigned int hashlenui;
 495             const SSL_CIPHER *sslcipher = SSL_SESSION_get0_cipher(s->session);
 496
 497             insecret = s->early_secret;
 498             label = client_early_traffic;
 499             labellen = sizeof(client_early_traffic) - 1;
 500             log_label = CLIENT_EARLY_LABEL;
 501
 502             handlen = BIO_get_mem_data(s->s3.handshake_buffer, &hdata);
 503             if (handlen <= 0) {
 504                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_R_BAD_HANDSHAKE_LENGTH);
 505                 goto err;
 506             }
 507
 508             if (s->early_data_state == SSL_EARLY_DATA_CONNECTING
 509                     && s->max_early_data > 0
 510                     && s->session->ext.max_early_data == 0) {
 511                 /*
 512                  * If we are attempting to send early data, and we've decided to
 513                  * actually do it but max_early_data in s->session is 0 then we
 514                  * must be using an external PSK.
 515                  */
 516                 if (!ossl_assert(s->psksession != NULL
 517                         && s->max_early_data ==
 518                            s->psksession->ext.max_early_data)) {
 519                     SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 520                     goto err;
 521                 }
 522                 sslcipher = SSL_SESSION_get0_cipher(s->psksession);
 523             }
 524             if (sslcipher == NULL) {
 525                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_R_BAD_PSK);
 526                 goto err;
 527             }
 528
 529             /*
 530              * This ups the ref count on cipher so we better make sure we free
 531              * it again
 532              */
 533             if (!ssl_cipher_get_evp_cipher(sctx, sslcipher, &cipher)) {
 534                 /* Error is already recorded */
 535                 SSLfatal_alert(s, SSL_AD_INTERNAL_ERROR);
 536                 goto err;
 537             }
 538
 539             if (((EVP_CIPHER_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER) == 0)
 540                 && (!ssl_cipher_get_evp_md_mac(sctx, sslcipher, &mac_md,
 541                                                &mac_pkey_type, NULL))) {
 542                 SSLfatal_alert(s, SSL_AD_INTERNAL_ERROR);
 543                 goto err;
 544             }
 545
 546             /*
 547              * We need to calculate the handshake digest using the digest from
 548              * the session. We haven't yet selected our ciphersuite so we can't
 549              * use ssl_handshake_md().
 550              */
 551             mdctx = EVP_MD_CTX_new();
 552             if (mdctx == NULL) {
 553                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_EVP_LIB);
 554                 goto err;
 555             }
 556
 557             md = ssl_md(sctx, sslcipher->algorithm2);
 558             if (md == NULL || !EVP_DigestInit_ex(mdctx, md, NULL)
 559                     || !EVP_DigestUpdate(mdctx, hdata, handlen)
 560                     || !EVP_DigestFinal_ex(mdctx, hashval, &hashlenui)) {
 561                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 562                 EVP_MD_CTX_free(mdctx);
 563                 goto err;
 564             }
 565             hashlen = hashlenui;
 566             EVP_MD_CTX_free(mdctx);
 567
 568             if (!tls13_hkdf_expand(s, md, insecret,
 569                                    early_exporter_master_secret,
 570                                    sizeof(early_exporter_master_secret) - 1,
 571                                    hashval, hashlen,
 572                                    s->early_exporter_master_secret, hashlen,
 573                                    1)) {
 574                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 575                 goto err;
 576             }
 577
 578             if (!ssl_log_secret(s, EARLY_EXPORTER_SECRET_LABEL,
 579                                 s->early_exporter_master_secret, hashlen)) {
 580                 /* SSLfatal() already called */
 581                 goto err;
 582             }
 583         } else if (which & SSL3_CC_HANDSHAKE) {
 584             insecret = s->handshake_secret;
 585             finsecret = s->client_finished_secret;
 586             finsecretlen = EVP_MD_get_size(ssl_handshake_md(s));
 587             if (finsecretlen <= 0) {
 588                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 589                 goto err;
 590             }
 591             label = client_handshake_traffic;
 592             labellen = sizeof(client_handshake_traffic) - 1;
 593             log_label = CLIENT_HANDSHAKE_LABEL;
 594             /*
 595              * The handshake hash used for the server read/client write handshake
 596              * traffic secret is the same as the hash for the server
 597              * write/client read handshake traffic secret. However, if we
 598              * processed early data then we delay changing the server
 599              * read/client write cipher state until later, and the handshake
 600              * hashes have moved on. Therefore we use the value saved earlier
 601              * when we did the server write/client read change cipher state.
 602              */
 603             hash = s->handshake_traffic_hash;
 604         } else {
 605             insecret = s->master_secret;
 606             label = client_application_traffic;
 607             labellen = sizeof(client_application_traffic) - 1;
 608             log_label = CLIENT_APPLICATION_LABEL;
 609             /*
 610              * For this we only use the handshake hashes up until the server
 611              * Finished hash. We do not include the client's Finished, which is
 612              * what ssl_handshake_hash() would give us. Instead we use the
 613              * previously saved value.
 614              */
 615             hash = s->server_finished_hash;
 616         }
 617     } else {
 618         /* Early data never applies to client-read/server-write */
 619         if (which & SSL3_CC_HANDSHAKE) {
 620             insecret = s->handshake_secret;
 621             finsecret = s->server_finished_secret;
 622             finsecretlen = EVP_MD_get_size(ssl_handshake_md(s));
 623             if (finsecretlen <= 0) {
 624                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 625                 goto err;
 626             }
 627             label = server_handshake_traffic;
 628             labellen = sizeof(server_handshake_traffic) - 1;
 629             log_label = SERVER_HANDSHAKE_LABEL;
 630         } else {
 631             insecret = s->master_secret;
 632             label = server_application_traffic;
 633             labellen = sizeof(server_application_traffic) - 1;
 634             log_label = SERVER_APPLICATION_LABEL;
 635         }
 636     }
 637
 638     if ((which & SSL3_CC_EARLY) == 0) {
 639         md = ssl_handshake_md(s);
 640         cipher = s->s3.tmp.new_sym_enc;
 641         mac_md = s->s3.tmp.new_hash;
 642         mac_pkey_type = s->s3.tmp.new_mac_pkey_type;
 643         if (!ssl3_digest_cached_records(s, 1)
 644                 || !ssl_handshake_hash(s, hashval, sizeof(hashval), &hashlen)) {
 645             /* SSLfatal() already called */;
 646             goto err;
 647         }
 648     }
 649
 650     /*
 651      * Save the hash of handshakes up to now for use when we calculate the
 652      * client application traffic secret
 653      */
 654     if (label == server_application_traffic)
 655         memcpy(s->server_finished_hash, hashval, hashlen);
 656
 657     if (label == server_handshake_traffic)
 658         memcpy(s->handshake_traffic_hash, hashval, hashlen);
 659
 660     if (label == client_application_traffic) {
 661         /*
 662          * We also create the resumption master secret, but this time use the
 663          * hash for the whole handshake including the Client Finished
 664          */
 665         if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
 666                                resumption_master_secret,
 667                                sizeof(resumption_master_secret) - 1,
 668                                hashval, hashlen, s->resumption_master_secret,
 669                                hashlen, 1)) {
 670             /* SSLfatal() already called */
 671             goto err;
 672         }
 673     }
 674
 675     /* check whether cipher is known */
 676     if (!ossl_assert(cipher != NULL))
 677         goto err;
 678
 679     if (!derive_secret_key_and_iv(s, md, cipher, mac_pkey_type, mac_md,
 680                                   insecret, hash, label, labellen, secret, key,
 681                                   &keylen, &iv, &ivlen, &taglen)) {
 682         /* SSLfatal() already called */
 683         goto err;
 684     }
 685
 686     if (label == server_application_traffic) {
 687         memcpy(s->server_app_traffic_secret, secret, hashlen);
 688         /* Now we create the exporter master secret */
 689         if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
 690                                exporter_master_secret,
 691                                sizeof(exporter_master_secret) - 1,
 692                                hash, hashlen, s->exporter_master_secret,
 693                                hashlen, 1)) {
 694             /* SSLfatal() already called */
 695             goto err;
 696         }
 697
 698         if (!ssl_log_secret(s, EXPORTER_SECRET_LABEL, s->exporter_master_secret,
 699                             hashlen)) {
 700             /* SSLfatal() already called */
 701             goto err;
 702         }
 703     } else if (label == client_application_traffic)
 704         memcpy(s->client_app_traffic_secret, secret, hashlen);
 705
 706     if (!ssl_log_secret(s, log_label, secret, hashlen)) {
 707         /* SSLfatal() already called */
 708         goto err;
 709     }
 710
 711     if (finsecret != NULL
 712             && !tls13_derive_finishedkey(s, ssl_handshake_md(s), secret,
 713                                          finsecret, (size_t)finsecretlen)) {
 714         /* SSLfatal() already called */
 715         goto err;
 716     }
 717
 718     if ((which & SSL3_CC_WRITE) != 0) {
 719         if (!s->server && label == client_early_traffic)
 720             s->rlayer.wrlmethod->set_plain_alerts(s->rlayer.wrl, 1);
 721         else
 722             s->rlayer.wrlmethod->set_plain_alerts(s->rlayer.wrl, 0);
 723     }
 724
 725     level = (which & SSL3_CC_EARLY) != 0
 726             ? OSSL_RECORD_PROTECTION_LEVEL_EARLY
 727             : ((which &SSL3_CC_HANDSHAKE) != 0
 728                ? OSSL_RECORD_PROTECTION_LEVEL_HANDSHAKE
 729                : OSSL_RECORD_PROTECTION_LEVEL_APPLICATION);
 730
 731     if (!ssl_set_new_record_layer(s, s->version,
 732                                   direction,
 733                                   level, secret, hashlen, key, keylen, iv,
 734                                   ivlen, NULL, 0, cipher, taglen,
 735                                   mac_pkey_type, mac_md, NULL, md)) {
 736         /* SSLfatal already called */
 737         goto err;
 738     }
 739
 740     ret = 1;
 741  err:
 742     if ((which & SSL3_CC_EARLY) != 0) {
 743         /* We up-refed this so now we need to down ref */
 744         if ((EVP_CIPHER_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER) == 0)
 745             ssl_evp_md_free(mac_md);
 746         ssl_evp_cipher_free(cipher);
 747     }
 748     OPENSSL_cleanse(key, sizeof(key));
 749     OPENSSL_cleanse(secret, sizeof(secret));
 750     if (iv != iv_intern)
 751         OPENSSL_free(iv);
 752     return ret;
 753 }
 754
 755 int tls13_update_key(SSL_CONNECTION *s, int sending)
 756 {
 757     /* ASCII: "traffic upd", in hex for EBCDIC compatibility */
 758     static const unsigned char application_traffic[] = "\x74\x72\x61\x66\x66\x69\x63\x20\x75\x70\x64";
 759     const EVP_MD *md = ssl_handshake_md(s);
 760     size_t hashlen;
 761     unsigned char key[EVP_MAX_KEY_LENGTH];
 762     unsigned char *insecret;
 763     unsigned char secret[EVP_MAX_MD_SIZE];
 764     char *log_label;
 765     size_t keylen, ivlen, taglen;
 766     int ret = 0, l;
 767     int direction = sending ? OSSL_RECORD_DIRECTION_WRITE
 768                             : OSSL_RECORD_DIRECTION_READ;
 769     unsigned char iv_intern[EVP_MAX_IV_LENGTH];
 770     unsigned char *iv = iv_intern;
 771
 772     if ((l = EVP_MD_get_size(md)) <= 0) {
 773         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 774         return 0;
 775     }
 776     hashlen = (size_t)l;
 777
 778     if (s->server == sending)
 779         insecret = s->server_app_traffic_secret;
 780     else
 781         insecret = s->client_app_traffic_secret;
 782
 783     if (!derive_secret_key_and_iv(s, md,
 784                                   s->s3.tmp.new_sym_enc,
 785                                   s->s3.tmp.new_mac_pkey_type, s->s3.tmp.new_hash,
 786                                   insecret, NULL,
 787                                   application_traffic,
 788                                   sizeof(application_traffic) - 1, secret, key,
 789                                   &keylen, &iv, &ivlen, &taglen)) {
 790         /* SSLfatal() already called */
 791         goto err;
 792     }
 793
 794     memcpy(insecret, secret, hashlen);
 795
 796     if (!ssl_set_new_record_layer(s, s->version,
 797                             direction,
 798                             OSSL_RECORD_PROTECTION_LEVEL_APPLICATION,
 799                             insecret, hashlen, key, keylen, iv, ivlen, NULL, 0,
 800                             s->s3.tmp.new_sym_enc, taglen, NID_undef, NULL,
 801                             NULL, md)) {
 802         /* SSLfatal already called */
 803         goto err;
 804     }
 805
 806     /* Call Key log on successful traffic secret update */
 807     log_label = s->server == sending ? SERVER_APPLICATION_N_LABEL : CLIENT_APPLICATION_N_LABEL;
 808     if (!ssl_log_secret(s, log_label, secret, hashlen)) {
 809         /* SSLfatal() already called */
 810         goto err;
 811     }
 812     ret = 1;
 813  err:
 814     OPENSSL_cleanse(key, sizeof(key));
 815     OPENSSL_cleanse(secret, sizeof(secret));
 816     if (iv != iv_intern)
 817         OPENSSL_free(iv);
 818     return ret;
 819 }
 820
 821 int tls13_alert_code(int code)
 822 {
 823     /* There are 2 additional alerts in TLSv1.3 compared to TLSv1.2 */
 824     if (code == SSL_AD_MISSING_EXTENSION || code == SSL_AD_CERTIFICATE_REQUIRED)
 825         return code;
 826
 827     return tls1_alert_code(code);
 828 }
 829
 830 int tls13_export_keying_material(SSL_CONNECTION *s,
 831                                  unsigned char *out, size_t olen,
 832                                  const char *label, size_t llen,
 833                                  const unsigned char *context,
 834                                  size_t contextlen, int use_context)
 835 {
 836     unsigned char exportsecret[EVP_MAX_MD_SIZE];
 837     /* ASCII: "exporter", in hex for EBCDIC compatibility */
 838     static const unsigned char exporterlabel[] = "\x65\x78\x70\x6F\x72\x74\x65\x72";
 839     unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE];
 840     const EVP_MD *md = ssl_handshake_md(s);
 841     EVP_MD_CTX *ctx = EVP_MD_CTX_new();
 842     unsigned int hashsize, datalen;
 843     int ret = 0;
 844
 845     if (ctx == NULL || md == NULL || !ossl_statem_export_allowed(s))
 846         goto err;
 847
 848     if (!use_context)
 849         contextlen = 0;
 850
 851     if (EVP_DigestInit_ex(ctx, md, NULL) <= 0
 852             || EVP_DigestUpdate(ctx, context, contextlen) <= 0
 853             || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0
 854             || EVP_DigestInit_ex(ctx, md, NULL) <= 0
 855             || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0
 856             || !tls13_hkdf_expand(s, md, s->exporter_master_secret,
 857                                   (const unsigned char *)label, llen,
 858                                   data, datalen, exportsecret, hashsize, 0)
 859             || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel,
 860                                   sizeof(exporterlabel) - 1, hash, hashsize,
 861                                   out, olen, 0))
 862         goto err;
 863
 864     ret = 1;
 865  err:
 866     EVP_MD_CTX_free(ctx);
 867     return ret;
 868 }
 869
 870 int tls13_export_keying_material_early(SSL_CONNECTION *s,
 871                                        unsigned char *out, size_t olen,
 872                                        const char *label, size_t llen,
 873                                        const unsigned char *context,
 874                                        size_t contextlen)
 875 {
 876     /* ASCII: "exporter", in hex for EBCDIC compatibility */
 877     static const unsigned char exporterlabel[] = "\x65\x78\x70\x6F\x72\x74\x65\x72";
 878     unsigned char exportsecret[EVP_MAX_MD_SIZE];
 879     unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE];
 880     const EVP_MD *md;
 881     EVP_MD_CTX *ctx = EVP_MD_CTX_new();
 882     unsigned int hashsize, datalen;
 883     int ret = 0;
 884     const SSL_CIPHER *sslcipher;
 885
 886     if (ctx == NULL || !ossl_statem_export_early_allowed(s))
 887         goto err;
 888
 889     if (!s->server && s->max_early_data > 0
 890             && s->session->ext.max_early_data == 0)
 891         sslcipher = SSL_SESSION_get0_cipher(s->psksession);
 892     else
 893         sslcipher = SSL_SESSION_get0_cipher(s->session);
 894
 895     md = ssl_md(SSL_CONNECTION_GET_CTX(s), sslcipher->algorithm2);
 896
 897     /*
 898      * Calculate the hash value and store it in |data|. The reason why
 899      * the empty string is used is that the definition of TLS-Exporter
 900      * is like so:
 901      *
 902      * TLS-Exporter(label, context_value, key_length) =
 903      *     HKDF-Expand-Label(Derive-Secret(Secret, label, ""),
 904      *                       "exporter", Hash(context_value), key_length)
 905      *
 906      * Derive-Secret(Secret, Label, Messages) =
 907      *       HKDF-Expand-Label(Secret, Label,
 908      *                         Transcript-Hash(Messages), Hash.length)
 909      *
 910      * Here Transcript-Hash is the cipher suite hash algorithm.
 911      */
 912     if (md == NULL
 913             || EVP_DigestInit_ex(ctx, md, NULL) <= 0
 914             || EVP_DigestUpdate(ctx, context, contextlen) <= 0
 915             || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0
 916             || EVP_DigestInit_ex(ctx, md, NULL) <= 0
 917             || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0
 918             || !tls13_hkdf_expand(s, md, s->early_exporter_master_secret,
 919                                   (const unsigned char *)label, llen,
 920                                   data, datalen, exportsecret, hashsize, 0)
 921             || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel,
 922                                   sizeof(exporterlabel) - 1, hash, hashsize,
 923                                   out, olen, 0))
 924         goto err;
 925
 926     ret = 1;
 927  err:
 928     EVP_MD_CTX_free(ctx);
 929     return ret;
 930 }