/*

 * Copyright (C) 2001-2012 Free Software Foundation, Inc.

 * Copyright (C) 2017 Red Hat, Inc.

 *

 * Author: Nikos Mavrogiannopoulos

 *

 * This file is part of GnuTLS.

 *

 * The GnuTLS is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public License

 * as published by the Free Software Foundation; either version 2.1 of

 * the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with this program.  If not, see <https://www.gnu.org/licenses/>

 *

 */

/* Functions that are supposed to run after the handshake procedure is

 * finished. These functions activate the established security parameters.

 */

#include "gnutls_int.h"

#include <constate.h>

#include "errors.h"

#include "fips.h"

#include <kx.h>

#include <algorithms.h>

#include <num.h>

#include <datum.h>

#include <state.h>

#include <hello_ext.h>

#include <buffers.h>

#include "dtls.h"

#include "secrets.h"

#include "handshake.h"

#include "crypto-api.h"

#include "locks.h"

static const char keyexp[] = "key expansion";

static const int keyexp_length = sizeof(keyexp) - 1;

static int

_tls13_init_record_state(gnutls_cipher_algorithm_t algo,

       record_state_st * state);

/* This function is to be called after handshake, when master_secret,

 *  client_random and server_random have been initialized. 

 * This function creates the keys and stores them into pending session.

 * (session->cipher_specs)

 */

static int

_gnutls_set_keys(gnutls_session_t session, record_parameters_st * params,

     unsigned hash_size, unsigned IV_size, unsigned key_size)

{

  uint8_t rnd[2 * GNUTLS_RANDOM_SIZE];

  int pos, ret;

  int block_size;

  char buf[4 * MAX_HASH_SIZE + 4 * MAX_CIPHER_KEY_SIZE +

     4 * MAX_CIPHER_BLOCK_SIZE];

  /* avoid using malloc */

  uint8_t key_block[2 * MAX_HASH_SIZE + 2 * MAX_CIPHER_KEY_SIZE +

        2 * MAX_CIPHER_BLOCK_SIZE];

  record_state_st *client_write, *server_write;

  if (session->security_parameters.entity == GNUTLS_CLIENT) {

    client_write = &params->write;

    server_write = &params->read;

  } else {

    client_write = &params->read;

    server_write = &params->write;

  }

  block_size = 2 * hash_size + 2 * key_size;

  block_size += 2 * IV_size;

  memcpy(rnd, session->security_parameters.server_random,

         GNUTLS_RANDOM_SIZE);

  memcpy(&rnd[GNUTLS_RANDOM_SIZE],

         session->security_parameters.client_random, GNUTLS_RANDOM_SIZE);

  _gnutls_memory_mark_defined(session->security_parameters.master_secret,

            GNUTLS_MASTER_SIZE);

#ifdef ENABLE_SSL3

  if (get_num_version(session) == GNUTLS_SSL3) {  /* SSL 3 */

    ret =

        _gnutls_ssl3_generate_random

        (session->security_parameters.master_secret,

         GNUTLS_MASTER_SIZE, rnd, 2 * GNUTLS_RANDOM_SIZE,

         block_size, key_block);

  } else      /* TLS 1.0+ */

#endif

    ret =

        _gnutls_PRF(session,

        session->security_parameters.master_secret,

        GNUTLS_MASTER_SIZE, keyexp, keyexp_length,

        rnd, 2 * GNUTLS_RANDOM_SIZE, block_size,

        key_block);

  if (ret < 0) {

    _gnutls_memory_mark_undefined(session->

                security_parameters.master_secret,

                GNUTLS_MASTER_SIZE);

    return gnutls_assert_val(ret);

  }

  _gnutls_hard_log("INT: KEY BLOCK[%d]: %s\n", block_size,

       _gnutls_bin2hex(key_block, block_size, buf,

           sizeof(buf), NULL));

  pos = 0;

  if (hash_size > 0) {

    assert(hash_size <= sizeof(client_write->mac_key));

    client_write->mac_key_size = hash_size;

    memcpy(client_write->mac_key, &key_block[pos], hash_size);

    pos += hash_size;

    server_write->mac_key_size = hash_size;

    memcpy(server_write->mac_key, &key_block[pos], hash_size);

    pos += hash_size;

    _gnutls_hard_log("INT: CLIENT MAC KEY [%d]: %s\n",

         client_write->mac_key_size,

         _gnutls_bin2hex(client_write->mac_key,

             hash_size,

             buf, sizeof(buf), NULL));

    _gnutls_hard_log("INT: SERVER MAC KEY [%d]: %s\n",

         server_write->mac_key_size,

         _gnutls_bin2hex(server_write->mac_key,

             hash_size,

             buf, sizeof(buf), NULL));

  }

  if (key_size > 0) {

    assert(key_size <= sizeof(client_write->key));

    client_write->key_size = key_size;

    memcpy(client_write->key, &key_block[pos], key_size);

    pos += key_size;

    server_write->key_size = key_size;

    memcpy(server_write->key, &key_block[pos], key_size);

    pos += key_size;

    _gnutls_hard_log("INT: CLIENT WRITE KEY [%d]: %s\n",

         key_size,

         _gnutls_bin2hex(client_write->key,

             key_size,

             buf, sizeof(buf), NULL));

    _gnutls_hard_log("INT: SERVER WRITE KEY [%d]: %s\n",

         key_size,

         _gnutls_bin2hex(server_write->key,

             key_size,

             buf, sizeof(buf), NULL));

  }

  /* IV generation in export and non export ciphers.

   */

  if (IV_size > 0) {

    assert(IV_size <= sizeof(client_write->iv));

    client_write->iv_size = IV_size;

    memcpy(client_write->iv, &key_block[pos], IV_size);

    pos += IV_size;

    server_write->iv_size = IV_size;

    memcpy(server_write->iv, &key_block[pos], IV_size);

    _gnutls_hard_log("INT: CLIENT WRITE IV [%d]: %s\n",

         client_write->iv_size,

         _gnutls_bin2hex(client_write->iv,

             client_write->iv_size,

             buf, sizeof(buf), NULL));

    _gnutls_hard_log("INT: SERVER WRITE IV [%d]: %s\n",

         server_write->iv_size,

         _gnutls_bin2hex(server_write->iv,

             server_write->iv_size,

             buf, sizeof(buf), NULL));

  }

  return 0;

}

static int

_tls13_update_keys(gnutls_session_t session, hs_stage_t stage,

       record_parameters_st * params,

       unsigned iv_size, unsigned key_size)

{

  uint8_t key_block[MAX_CIPHER_KEY_SIZE];

  uint8_t iv_block[MAX_CIPHER_IV_SIZE];

  char buf[65];

  record_state_st *upd_state;

  record_parameters_st *prev = NULL;

  int ret;

  /* generate new keys for direction needed and copy old from previous epoch */

  if (stage == STAGE_UPD_OURS) {

    upd_state = &params->write;

    ret = _gnutls_epoch_get(session, EPOCH_READ_CURRENT, &prev);

    if (ret < 0)

      return gnutls_assert_val(ret);

    assert(prev != NULL);

    params->read.sequence_number = prev->read.sequence_number;

    params->read.key_size = prev->read.key_size;

    memcpy(params->read.key, prev->read.key, prev->read.key_size);

    _gnutls_hard_log("INT: READ KEY [%d]: %s\n",

         params->read.key_size,

         _gnutls_bin2hex(params->read.key,

             params->read.key_size, buf,

             sizeof(buf), NULL));

    params->read.iv_size = prev->read.iv_size;

    memcpy(params->read.iv, prev->read.iv, prev->read.key_size);

    _gnutls_hard_log("INT: READ IV [%d]: %s\n",

         params->read.iv_size,

         _gnutls_bin2hex(params->read.iv,

             params->read.iv_size, buf,

             sizeof(buf), NULL));

  } else {

    upd_state = &params->read;

    ret = _gnutls_epoch_get(session, EPOCH_WRITE_CURRENT, &prev);

    if (ret < 0)

      return gnutls_assert_val(ret);

    assert(prev != NULL);

    params->write.sequence_number = prev->write.sequence_number;

    params->write.key_size = prev->write.key_size;

    memcpy(params->write.key, prev->write.key,

           prev->write.key_size);

    _gnutls_hard_log("INT: WRITE KEY [%d]: %s\n",

         params->write.key_size,

         _gnutls_bin2hex(params->write.key,

             params->write.key_size, buf,

             sizeof(buf), NULL));

    params->write.iv_size = prev->write.iv_size;

    memcpy(params->write.iv, prev->write.iv, prev->write.iv_size);

    _gnutls_hard_log("INT: WRITE IV [%d]: %s\n",

         params->write.iv_size,

         _gnutls_bin2hex(params->write.iv,

             params->write.iv_size, buf,

             sizeof(buf), NULL));

  }

  if ((session->security_parameters.entity == GNUTLS_CLIENT

       && stage == STAGE_UPD_OURS)

      || (session->security_parameters.entity == GNUTLS_SERVER

    && stage == STAGE_UPD_PEERS)) {

    /* client keys */

    ret = _tls13_expand_secret(session, APPLICATION_TRAFFIC_UPDATE,

             sizeof(APPLICATION_TRAFFIC_UPDATE) -

             1, NULL, 0,

             session->key.proto.tls13.ap_ckey,

             session->security_parameters.

             prf->output_size,

             session->key.proto.tls13.ap_ckey);

    if (ret < 0)

      return gnutls_assert_val(ret);

    ret =

        _tls13_expand_secret(session, "key", 3, NULL, 0,

           session->key.proto.tls13.ap_ckey,

           key_size, key_block);

    if (ret < 0)

      return gnutls_assert_val(ret);

    ret =

        _tls13_expand_secret(session, "iv", 2, NULL, 0,

           session->key.proto.tls13.ap_ckey,

           iv_size, iv_block);

    if (ret < 0)

      return gnutls_assert_val(ret);

  } else {

    ret = _tls13_expand_secret(session, APPLICATION_TRAFFIC_UPDATE,

             sizeof(APPLICATION_TRAFFIC_UPDATE) -

             1, NULL, 0,

             session->key.proto.tls13.ap_skey,

             session->security_parameters.

             prf->output_size,

             session->key.proto.tls13.ap_skey);

    if (ret < 0)

      return gnutls_assert_val(ret);

    ret =

        _tls13_expand_secret(session, "key", 3, NULL, 0,

           session->key.proto.tls13.ap_skey,

           key_size, key_block);

    if (ret < 0)

      return gnutls_assert_val(ret);

    ret =

        _tls13_expand_secret(session, "iv", 2, NULL, 0,

           session->key.proto.tls13.ap_skey,

           iv_size, iv_block);

    if (ret < 0)

      return gnutls_assert_val(ret);

  }

  upd_state->mac_key_size = 0;

  assert(key_size <= sizeof(upd_state->key));

  memcpy(upd_state->key, key_block, key_size);

  upd_state->key_size = key_size;

  _gnutls_hard_log("INT: NEW %s KEY [%d]: %s\n",

       (upd_state == &params->read) ? "READ" : "WRITE",

       key_size,

       _gnutls_bin2hex(key_block, key_size,

           buf, sizeof(buf), NULL));

  if (iv_size > 0) {

    assert(iv_size <= sizeof(upd_state->iv));

    memcpy(upd_state->iv, iv_block, iv_size);

    upd_state->iv_size = iv_size;

    _gnutls_hard_log("INT: NEW %s IV [%d]: %s\n",

         (upd_state ==

          &params->read) ? "READ" : "WRITE", iv_size,

         _gnutls_bin2hex(iv_block, iv_size, buf,

             sizeof(buf), NULL));

  }

  return 0;

}

static int

_tls13_set_early_keys(gnutls_session_t session,

          record_parameters_st * params,

          unsigned iv_size, unsigned key_size)

{

  uint8_t key_block[MAX_CIPHER_KEY_SIZE];

  uint8_t iv_block[MAX_CIPHER_IV_SIZE];

  char buf[65];

  record_state_st *early_state;

  int ret;

  if (session->security_parameters.entity == GNUTLS_CLIENT &&

      !(session->internals.hsk_flags & HSK_TLS13_TICKET_SENT)) {

    return GNUTLS_E_INVALID_REQUEST;

  }

  ret =

      _tls13_expand_secret2(session->internals.

          resumed_security_parameters.prf, "key", 3,

          NULL, 0, session->key.proto.tls13.e_ckey,

          key_size, key_block);

  if (ret < 0)

    return gnutls_assert_val(ret);

  ret =

      _tls13_expand_secret2(session->internals.

          resumed_security_parameters.prf, "iv", 2,

          NULL, 0, session->key.proto.tls13.e_ckey,

          iv_size, iv_block);

  if (ret < 0)

    return gnutls_assert_val(ret);

  if (session->security_parameters.entity == GNUTLS_CLIENT) {

    early_state = &params->write;

  } else {

    early_state = &params->read;

  }

  early_state->mac_key_size = 0;

  assert(key_size <= sizeof(early_state->key));

  memcpy(early_state->key, key_block, key_size);

  early_state->key_size = key_size;

  _gnutls_hard_log("INT: EARLY KEY [%d]: %s\n",

       key_size,

       _gnutls_bin2hex(key_block, key_size,

           buf, sizeof(buf), NULL));

  if (iv_size > 0) {

    assert(iv_size <= sizeof(early_state->iv));

    memcpy(early_state->iv, iv_block, iv_size);

    early_state->iv_size = iv_size;

    _gnutls_hard_log("INT: EARLY IV [%d]: %s\n",

         iv_size,

         _gnutls_bin2hex(iv_block, iv_size,

             buf, sizeof(buf), NULL));

  }

  return 0;

}

static int

_tls13_set_keys(gnutls_session_t session, hs_stage_t stage,

    record_parameters_st * params,

    unsigned iv_size, unsigned key_size)

{

  uint8_t ckey_block[MAX_CIPHER_KEY_SIZE];

  uint8_t civ_block[MAX_CIPHER_IV_SIZE];

  uint8_t skey_block[MAX_CIPHER_KEY_SIZE];

  uint8_t siv_block[MAX_CIPHER_IV_SIZE];

  char buf[65];

  record_state_st *client_write, *server_write;

  const char *label;

  unsigned label_size, hsk_len;

  const char *keylog_label;

  void *ckey, *skey;

  int ret;

  if (stage == STAGE_UPD_OURS || stage == STAGE_UPD_PEERS)

    return _tls13_update_keys(session, stage,

            params, iv_size, key_size);

  else if (stage == STAGE_EARLY)

    return _tls13_set_early_keys(session,

               params, iv_size, key_size);

  else if (stage == STAGE_HS) {

    label = HANDSHAKE_CLIENT_TRAFFIC_LABEL;

    label_size = sizeof(HANDSHAKE_CLIENT_TRAFFIC_LABEL) - 1;

    hsk_len = session->internals.handshake_hash_buffer.length;

    keylog_label = "CLIENT_HANDSHAKE_TRAFFIC_SECRET";

    ckey = session->key.proto.tls13.hs_ckey;

  } else {

    label = APPLICATION_CLIENT_TRAFFIC_LABEL;

    label_size = sizeof(APPLICATION_CLIENT_TRAFFIC_LABEL) - 1;

    hsk_len =

        session->

        internals.handshake_hash_buffer_server_finished_len;

    keylog_label = "CLIENT_TRAFFIC_SECRET_0";

    ckey = session->key.proto.tls13.ap_ckey;

  }

  ret = _tls13_derive_secret(session, label, label_size,

           session->internals.

           handshake_hash_buffer.data, hsk_len,

           session->key.proto.tls13.temp_secret, ckey);

  if (ret < 0)

    return gnutls_assert_val(ret);

  ret = _gnutls_call_keylog_func(session, keylog_label,

               ckey,

               session->security_parameters.

               prf->output_size);

  if (ret < 0)

    return gnutls_assert_val(ret);

  /* client keys */

  ret =

      _tls13_expand_secret(session, "key", 3, NULL, 0, ckey, key_size,

         ckey_block);

  if (ret < 0)

    return gnutls_assert_val(ret);

  ret =

      _tls13_expand_secret(session, "iv", 2, NULL, 0, ckey, iv_size,

         civ_block);

  if (ret < 0)

    return gnutls_assert_val(ret);

  /* server keys */

  if (stage == STAGE_HS) {

    label = HANDSHAKE_SERVER_TRAFFIC_LABEL;

    label_size = sizeof(HANDSHAKE_SERVER_TRAFFIC_LABEL) - 1;

    keylog_label = "SERVER_HANDSHAKE_TRAFFIC_SECRET";

    skey = session->key.proto.tls13.hs_skey;

  } else {

    label = APPLICATION_SERVER_TRAFFIC_LABEL;

    label_size = sizeof(APPLICATION_SERVER_TRAFFIC_LABEL) - 1;

    keylog_label = "SERVER_TRAFFIC_SECRET_0";

    skey = session->key.proto.tls13.ap_skey;

  }

  ret = _tls13_derive_secret(session, label, label_size,

           session->internals.

           handshake_hash_buffer.data, hsk_len,

           session->key.proto.tls13.temp_secret, skey);

  if (ret < 0)

    return gnutls_assert_val(ret);

  ret = _gnutls_call_keylog_func(session, keylog_label,

               skey,

               session->security_parameters.

               prf->output_size);

  if (ret < 0)

    return gnutls_assert_val(ret);

  ret =

      _tls13_expand_secret(session, "key", 3, NULL, 0, skey, key_size,

         skey_block);

  if (ret < 0)

    return gnutls_assert_val(ret);

  ret =

      _tls13_expand_secret(session, "iv", 2, NULL, 0, skey, iv_size,

         siv_block);

  if (ret < 0)

    return gnutls_assert_val(ret);

  if (session->security_parameters.entity == GNUTLS_CLIENT) {

    client_write = &params->write;

    server_write = &params->read;

  } else {

    client_write = &params->read;

    server_write = &params->write;

  }

  client_write->mac_key_size = 0;

  server_write->mac_key_size = 0;

  assert(key_size <= sizeof(client_write->key));

  memcpy(client_write->key, ckey_block, key_size);

  client_write->key_size = key_size;

  _gnutls_hard_log("INT: CLIENT WRITE KEY [%d]: %s\n",

       key_size,

       _gnutls_bin2hex(ckey_block, key_size,

           buf, sizeof(buf), NULL));

  memcpy(server_write->key, skey_block, key_size);

  server_write->key_size = key_size;

  _gnutls_hard_log("INT: SERVER WRITE KEY [%d]: %s\n",

       key_size,

       _gnutls_bin2hex(skey_block, key_size,

           buf, sizeof(buf), NULL));

  if (iv_size > 0) {

    assert(iv_size <= sizeof(client_write->iv));

    memcpy(client_write->iv, civ_block, iv_size);

    client_write->iv_size = iv_size;

    _gnutls_hard_log("INT: CLIENT WRITE IV [%d]: %s\n",

         iv_size,

         _gnutls_bin2hex(civ_block, iv_size,

             buf, sizeof(buf), NULL));

    memcpy(server_write->iv, siv_block, iv_size);

    server_write->iv_size = iv_size;

    _gnutls_hard_log("INT: SERVER WRITE IV [%d]: %s\n",

         iv_size,

         _gnutls_bin2hex(siv_block, iv_size,

             buf, sizeof(buf), NULL));

  }

  client_write->level = server_write->level = stage == STAGE_HS ?

      GNUTLS_ENCRYPTION_LEVEL_HANDSHAKE :

      GNUTLS_ENCRYPTION_LEVEL_APPLICATION;

  return 0;

}

static int

_gnutls_init_record_state(record_parameters_st * params,

        const version_entry_st * ver, int read,

        record_state_st * state)

{

  int ret;

  gnutls_datum_t *iv = NULL, _iv;

  gnutls_datum_t key;

  gnutls_datum_t mac;

  _iv.data = state->iv;

  _iv.size = state->iv_size;

  key.data = state->key;

  key.size = state->key_size;

  mac.data = state->mac_key;

  mac.size = state->mac_key_size;

  if (_gnutls_cipher_type(params->cipher) == CIPHER_BLOCK) {

    if (!_gnutls_version_has_explicit_iv(ver))

      iv = &_iv;

  } else if (_gnutls_cipher_type(params->cipher) == CIPHER_STREAM) {

    /* To handle GOST ciphersuites */

    if (_gnutls_cipher_get_implicit_iv_size(params->cipher))

      iv = &_iv;

  }

  ret = _gnutls_auth_cipher_init(&state->ctx.tls12,

               params->cipher, &key, iv,

               params->mac, &mac, params->etm,

#ifdef ENABLE_SSL3

               (ver->id == GNUTLS_SSL3) ? 1 : 0,

#endif

               1 - read /*1==encrypt */ );

  if (ret < 0 && params->cipher->id != GNUTLS_CIPHER_NULL) {

    _gnutls_switch_fips_state(GNUTLS_FIPS140_OP_ERROR);

    return gnutls_assert_val(ret);

  }

  if (is_cipher_algo_allowed(params->cipher->id))

    _gnutls_switch_fips_state(GNUTLS_FIPS140_OP_APPROVED);

  else

    _gnutls_switch_fips_state(GNUTLS_FIPS140_OP_NOT_APPROVED);

  return 0;

}

int

_gnutls_set_cipher_suite2(gnutls_session_t session,

        const gnutls_cipher_suite_entry_st * cs)

{

  const cipher_entry_st *cipher_algo;

  const mac_entry_st *mac_algo;

  record_parameters_st *params;

  int ret;

  const version_entry_st *ver = get_version(session);

  ret = _gnutls_epoch_get(session, EPOCH_NEXT, &params);

  if (ret < 0)

    return gnutls_assert_val(ret);

  cipher_algo = cipher_to_entry(cs->block_algorithm);

  mac_algo = mac_to_entry(cs->mac_algorithm);

  if (ver->tls13_sem && (session->internals.hsk_flags & HSK_HRR_SENT)) {

    if (params->initialized && (params->cipher != cipher_algo ||

              params->mac != mac_algo

              || cs !=

              session->security_parameters.cs))

      return

          gnutls_assert_val

          (GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER);

    return 0;

  }

  /* The params shouldn't have been initialized at this point, unless we

   * are doing trial encryption/decryption of early data.

   */

  if (unlikely

      (!((session->internals.hsk_flags & HSK_EARLY_DATA_IN_FLIGHT &&

    !IS_SERVER(session)) ||

         (session->internals.hsk_flags & HSK_EARLY_DATA_ACCEPTED &&

    IS_SERVER(session))) &&

       (params->initialized

        || params->cipher != NULL || params->mac != NULL))) {

    return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);

  }

  if (_gnutls_cipher_is_ok(cipher_algo) == 0

      || _gnutls_mac_is_ok(mac_algo) == 0)

    return gnutls_assert_val(GNUTLS_E_UNWANTED_ALGORITHM);

  if (_gnutls_version_has_selectable_prf(get_version(session))) {

    if (cs->prf == GNUTLS_MAC_UNKNOWN ||

        _gnutls_mac_is_ok(mac_to_entry(cs->prf)) == 0)

      return gnutls_assert_val(GNUTLS_E_UNWANTED_ALGORITHM);

    session->security_parameters.prf = mac_to_entry(cs->prf);

  } else {

    session->security_parameters.prf =

        mac_to_entry(GNUTLS_MAC_MD5_SHA1);

  }

  session->security_parameters.cs = cs;

  params->cipher = cipher_algo;

  params->mac = mac_algo;

  return 0;

}

/* Sets the next epoch to be a clone of the current one.

 * The keys are not cloned, only the cipher and MAC.

 */

int _gnutls_epoch_dup(gnutls_session_t session, unsigned int epoch_rel)

{

  record_parameters_st *prev;

  record_parameters_st *next;

  int ret;

  ret = _gnutls_epoch_get(session, epoch_rel, &prev);

  if (ret < 0)

    return gnutls_assert_val(ret);

  ret = _gnutls_epoch_get(session, EPOCH_NEXT, &next);

  if (ret < 0) {

    ret = _gnutls_epoch_setup_next(session, 0, &next);

    if (ret < 0)

      return gnutls_assert_val(ret);

  }

  if (next->initialized || next->cipher != NULL || next->mac != NULL)

    return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);

  next->cipher = prev->cipher;

  next->mac = prev->mac;

  return 0;

}

int _gnutls_epoch_set_keys(gnutls_session_t session, uint16_t epoch,

         hs_stage_t stage)

{

  int hash_size;

  int IV_size;

  int key_size;

  record_parameters_st *params;

  int ret;

  const version_entry_st *ver =

      stage == STAGE_EARLY && !IS_SERVER(session) ?

      session->internals.resumed_security_parameters.pversion :

      get_version(session);

  if (unlikely(ver == NULL))

    return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);

  ret = _gnutls_epoch_get(session, epoch, &params);

  if (ret < 0)

    return gnutls_assert_val(ret);

  if (params->initialized)

    return 0;

  _gnutls_record_log

      ("REC[%p]: Initializing epoch #%u\n", session, params->epoch);

  if (_gnutls_cipher_is_ok(params->cipher) == 0 ||

      _gnutls_mac_is_ok(params->mac) == 0)

    return gnutls_assert_val(GNUTLS_E_UNWANTED_ALGORITHM);

  if (_gnutls_version_has_explicit_iv(ver) &&

      (_gnutls_cipher_type(params->cipher) != CIPHER_BLOCK)) {

    IV_size = _gnutls_cipher_get_implicit_iv_size(params->cipher);

  } else {

    IV_size = _gnutls_cipher_get_iv_size(params->cipher);

  }

  key_size = _gnutls_cipher_get_key_size(params->cipher);

  hash_size = _gnutls_mac_get_key_size(params->mac);

  params->etm = session->security_parameters.etm;

  if (ver->tls13_sem) {

    ret = _tls13_set_keys

        (session, stage, params, IV_size, key_size);

    if (ret < 0)

      return gnutls_assert_val(ret);

    if (stage != STAGE_EARLY ||

        session->security_parameters.entity == GNUTLS_SERVER) {

      ret =

          _tls13_init_record_state(params->cipher->id,

                 &params->read);

      if (ret < 0)

        return gnutls_assert_val(ret);

    }

    if (stage != STAGE_EARLY ||

        session->security_parameters.entity == GNUTLS_CLIENT) {

      ret =

          _tls13_init_record_state(params->cipher->id,

                 &params->write);

      if (ret < 0)

        return gnutls_assert_val(ret);

    }

  } else {

    ret = _gnutls_set_keys

        (session, params, hash_size, IV_size, key_size);

    if (ret < 0)

      return gnutls_assert_val(ret);

    ret = _gnutls_init_record_state(params, ver, 1, &params->read);

    if (ret < 0)

      return gnutls_assert_val(ret);

    ret = _gnutls_init_record_state(params, ver, 0, &params->write);

    if (ret < 0)

      return gnutls_assert_val(ret);

  }

  /* The TLS1.3 limit of 256 additional bytes is also enforced under CBC

   * ciphers to ensure we interoperate with gnutls 2.12.x which could add padding

   * data exceeding the maximum. */

  if (ver->tls13_sem

      || _gnutls_cipher_type(params->cipher) == CIPHER_BLOCK) {

    session->internals.max_recv_size = 256;

  } else {

    session->internals.max_recv_size = 0;

  }

  if (!ver->tls13_sem) {

    session->internals.max_recv_size +=

        _gnutls_record_overhead(ver, params->cipher, params->mac,

              1);

    if (session->internals.allow_large_records != 0)

      session->internals.max_recv_size += EXTRA_COMP_SIZE;

  }

  session->internals.max_recv_size +=

      session->security_parameters.max_record_recv_size +

      RECORD_HEADER_SIZE(session);

  _dtls_reset_window(params);

  _gnutls_record_log("REC[%p]: Epoch #%u ready\n", session,

         params->epoch);

  params->initialized = 1;

  return 0;

}

void _gnutls_set_resumed_parameters(gnutls_session_t session)

{

  security_parameters_st *src =

      &session->internals.resumed_security_parameters;

  security_parameters_st *dst = &session->security_parameters;

  const version_entry_st *ver = get_version(session);

  /* Under TLS 1.3, these values are items which are not

   * negotiated on the subsequent session. */

  if (!ver->tls13_sem) {

    dst->cs = src->cs;

    _gnutls_memory_mark_defined(dst->master_secret,

              GNUTLS_MASTER_SIZE);

    memcpy(dst->master_secret, src->master_secret,

           GNUTLS_MASTER_SIZE);

    _gnutls_memory_mark_defined(dst->client_random,

              GNUTLS_RANDOM_SIZE);

    memcpy(dst->client_random, src->client_random,

           GNUTLS_RANDOM_SIZE);

    _gnutls_memory_mark_defined(dst->server_random,

              GNUTLS_RANDOM_SIZE);

    memcpy(dst->server_random, src->server_random,

           GNUTLS_RANDOM_SIZE);

    dst->ext_master_secret = src->ext_master_secret;

    dst->etm = src->etm;

    dst->prf = src->prf;

    dst->grp = src->grp;

    dst->pversion = src->pversion;

  }

  memcpy(dst->session_id, src->session_id, GNUTLS_MAX_SESSION_ID_SIZE);

  dst->session_id_size = src->session_id_size;

  dst->timestamp = src->timestamp;

  dst->client_ctype = src->client_ctype;

  dst->server_ctype = src->server_ctype;

  dst->client_auth_type = src->client_auth_type;

  dst->server_auth_type = src->server_auth_type;

  if (!ver->tls13_sem &&

      !(session->

        internals.hsk_flags & HSK_RECORD_SIZE_LIMIT_NEGOTIATED)) {

    dst->max_record_recv_size = src->max_record_recv_size;

    dst->max_record_send_size = src->max_record_send_size;

  }

}

/* Sets the current connection session to conform with the

 * Security parameters(pending session), and initializes encryption.

 * Actually it initializes and starts encryption ( so it needs

 * secrets and random numbers to have been negotiated)

 * This is to be called after sending the Change Cipher Spec packet.

 */

int _gnutls_connection_state_init(gnutls_session_t session)

{