text: /*
   * Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.
   *
   * Licensed under the OpenSSL license (the "License").  You may not use
   * this file except in compliance with the License.  You can obtain a copy
   * in the file LICENSE in the source distribution or at
   * https://www.openssl.org/source/license.html
   */
  
  #include <openssl/ocsp.h>
  #include "../ssl_locl.h"
  #include "statem_locl.h"
  #include "internal/cryptlib.h"
  
  #define COOKIE_STATE_FORMAT_VERSION     0
  
  /*
   * 2 bytes for packet length, 2 bytes for format version, 2 bytes for
   * protocol version, 2 bytes for group id, 2 bytes for cipher id, 1 byte for
   * key_share present flag, 4 bytes for timestamp, 2 bytes for the hashlen,
   * EVP_MAX_MD_SIZE for transcript hash, 1 byte for app cookie length, app cookie
   * length bytes, SHA256_DIGEST_LENGTH bytes for the HMAC of the whole thing.
   */
  #define MAX_COOKIE_SIZE (2 + 2 + 2 + 2 + 2 + 1 + 4 + 2 + EVP_MAX_MD_SIZE + 1 \
                           + SSL_COOKIE_LENGTH + SHA256_DIGEST_LENGTH)
  
  /*
   * Message header + 2 bytes for protocol version + number of random bytes +
   * + 1 byte for legacy session id length + number of bytes in legacy session id
   * + 2 bytes for ciphersuite + 1 byte for legacy compression
   * + 2 bytes for extension block length + 6 bytes for key_share extension
   * + 4 bytes for cookie extension header + the number of bytes in the cookie
   */
  #define MAX_HRR_SIZE    (SSL3_HM_HEADER_LENGTH + 2 + SSL3_RANDOM_SIZE + 1 \
                           + SSL_MAX_SSL_SESSION_ID_LENGTH + 2 + 1 + 2 + 6 + 4 \
                           + MAX_COOKIE_SIZE)
  
  /*
   * Parse the client's renegotiation binding and abort if it's not right
   */
  int tls_parse_ctos_renegotiate(SSL *s, PACKET *pkt, unsigned int context,
                                 X509 *x, size_t chainidx)
  {
      unsigned int ilen;
      const unsigned char *data;
  
      /* Parse the length byte */
      if (!PACKET_get_1(pkt, &ilen)
          || !PACKET_get_bytes(pkt, &data, ilen)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_RENEGOTIATE,
                   SSL_R_RENEGOTIATION_ENCODING_ERR);
          return 0;
      }
  
      /* Check that the extension matches */
      if (ilen != s->s3->previous_client_finished_len) {
          SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_TLS_PARSE_CTOS_RENEGOTIATE,
                   SSL_R_RENEGOTIATION_MISMATCH);
          return 0;
      }
  
      if (memcmp(data, s->s3->previous_client_finished,
                 s->s3->previous_client_finished_len)) {
          SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_TLS_PARSE_CTOS_RENEGOTIATE,
                   SSL_R_RENEGOTIATION_MISMATCH);
          return 0;
      }
  
      s->s3->send_connection_binding = 1;
  
      return 1;
  }
  
  /*-
   * The servername extension is treated as follows:
   *
   * - Only the hostname type is supported with a maximum length of 255.
   * - The servername is rejected if too long or if it contains zeros,
   *   in which case an fatal alert is generated.
   * - The servername field is maintained together with the session cache.
   * - When a session is resumed, the servername call back invoked in order
   *   to allow the application to position itself to the right context.
   * - The servername is acknowledged if it is new for a session or when
   *   it is identical to a previously used for the same session.
   *   Applications can control the behaviour.  They can at any time
   *   set a 'desirable' servername for a new SSL object. This can be the
   *   case for example with HTTPS when a Host: header field is received and
   *   a renegotiation is requested. In this case, a possible servername
   *   presented in the new client hello is only acknowledged if it matches
   *   the value of the Host: field.
   * - Applications must  use SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION
   *   if they provide for changing an explicit servername context for the
   *   session, i.e. when the session has been established with a servername
   *   extension.
   * - On session reconnect, the servername extension may be absent.
   */
  int tls_parse_ctos_server_name(SSL *s, PACKET *pkt, unsigned int context,
                                 X509 *x, size_t chainidx)
  {
      unsigned int servname_type;
      PACKET sni, hostname;
  
      if (!PACKET_as_length_prefixed_2(pkt, &sni)
          /* ServerNameList must be at least 1 byte long. */
          || PACKET_remaining(&sni) == 0) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_SERVER_NAME,
                   SSL_R_BAD_EXTENSION);
          return 0;
      }
  
      /*
       * Although the intent was for server_name to be extensible, RFC 4366
       * was not clear about it; and so OpenSSL among other implementations,
       * always and only allows a 'host_name' name types.
       * RFC 6066 corrected the mistake but adding new name types
       * is nevertheless no longer feasible, so act as if no other
       * SNI types can exist, to simplify parsing.
       *
       * Also note that the RFC permits only one SNI value per type,
       * i.e., we can only have a single hostname.
       */
      if (!PACKET_get_1(&sni, &servname_type)
          || servname_type != TLSEXT_NAMETYPE_host_name
          || !PACKET_as_length_prefixed_2(&sni, &hostname)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_SERVER_NAME,
                   SSL_R_BAD_EXTENSION);
          return 0;
      }
  
      if (!s->hit) {
          if (PACKET_remaining(&hostname) > TLSEXT_MAXLEN_host_name) {
              SSLfatal(s, SSL_AD_UNRECOGNIZED_NAME,
                       SSL_F_TLS_PARSE_CTOS_SERVER_NAME,
                       SSL_R_BAD_EXTENSION);
              return 0;
          }
  
          if (PACKET_contains_zero_byte(&hostname)) {
              SSLfatal(s, SSL_AD_UNRECOGNIZED_NAME,
                       SSL_F_TLS_PARSE_CTOS_SERVER_NAME,
                       SSL_R_BAD_EXTENSION);
              return 0;
          }
  
          OPENSSL_free(s->session->ext.hostname);
          s->session->ext.hostname = NULL;
          if (!PACKET_strndup(&hostname, &s->session->ext.hostname)) {
              SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_SERVER_NAME,
                       ERR_R_INTERNAL_ERROR);
              return 0;
          }
  
          s->servername_done = 1;
      } else {
          /*
           * TODO(openssl-team): if the SNI doesn't match, we MUST
           * fall back to a full handshake.
           */
          s->servername_done = s->session->ext.hostname
              && PACKET_equal(&hostname, s->session->ext.hostname,
                              strlen(s->session->ext.hostname));
  
          if (!s->servername_done && s->session->ext.hostname != NULL)
              s->ext.early_data_ok = 0;
      }
  
      return 1;
  }
  
  int tls_parse_ctos_maxfragmentlen(SSL *s, PACKET *pkt, unsigned int context,
                                    X509 *x, size_t chainidx)
  {
      unsigned int value;
  
      if (PACKET_remaining(pkt) != 1 || !PACKET_get_1(pkt, &value)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_MAXFRAGMENTLEN,
                   SSL_R_BAD_EXTENSION);
          return 0;
      }
  
      /* Received |value| should be a valid max-fragment-length code. */
      if (!IS_MAX_FRAGMENT_LENGTH_EXT_VALID(value)) {
          SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
                   SSL_F_TLS_PARSE_CTOS_MAXFRAGMENTLEN,
                   SSL_R_SSL3_EXT_INVALID_MAX_FRAGMENT_LENGTH);
          return 0;
      }
  
      /*
       * RFC 6066:  The negotiated length applies for the duration of the session
       * including session resumptions.
       * We should receive the same code as in resumed session !
       */
      if (s->hit && s->session->ext.max_fragment_len_mode != value) {
          SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
                   SSL_F_TLS_PARSE_CTOS_MAXFRAGMENTLEN,
                   SSL_R_SSL3_EXT_INVALID_MAX_FRAGMENT_LENGTH);
          return 0;
      }
  
      /*
       * Store it in session, so it'll become binding for us
       * and we'll include it in a next Server Hello.
       */
      s->session->ext.max_fragment_len_mode = value;
      return 1;
  }
  
  #ifndef OPENSSL_NO_SRP
  int tls_parse_ctos_srp(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
                         size_t chainidx)
  {
      PACKET srp_I;
  
      if (!PACKET_as_length_prefixed_1(pkt, &srp_I)
              || PACKET_contains_zero_byte(&srp_I)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR,
                   SSL_F_TLS_PARSE_CTOS_SRP,
                   SSL_R_BAD_EXTENSION);
          return 0;
      }
  
      /*
       * TODO(openssl-team): currently, we re-authenticate the user
       * upon resumption. Instead, we MUST ignore the login.
       */
      if (!PACKET_strndup(&srp_I, &s->srp_ctx.login)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_SRP,
                   ERR_R_INTERNAL_ERROR);
          return 0;
      }
  
      return 1;
  }
  #endif
  
  #ifndef OPENSSL_NO_EC
  int tls_parse_ctos_ec_pt_formats(SSL *s, PACKET *pkt, unsigned int context,
                                   X509 *x, size_t chainidx)
  {
      PACKET ec_point_format_list;
  
      if (!PACKET_as_length_prefixed_1(pkt, &ec_point_format_list)
          || PACKET_remaining(&ec_point_format_list) == 0) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_EC_PT_FORMATS,
                   SSL_R_BAD_EXTENSION);
          return 0;
      }
  
      if (!s->hit) {
          if (!PACKET_memdup(&ec_point_format_list,
                             &s->session->ext.ecpointformats,
                             &s->session->ext.ecpointformats_len)) {
              SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                       SSL_F_TLS_PARSE_CTOS_EC_PT_FORMATS, ERR_R_INTERNAL_ERROR);
              return 0;
          }
      }
  
      return 1;
  }
  #endif                          /* OPENSSL_NO_EC */
  
  int tls_parse_ctos_session_ticket(SSL *s, PACKET *pkt, unsigned int context,
                                    X509 *x, size_t chainidx)
  {
      if (s->ext.session_ticket_cb &&
              !s->ext.session_ticket_cb(s, PACKET_data(pkt),
                                    PACKET_remaining(pkt),
                                    s->ext.session_ticket_cb_arg)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                   SSL_F_TLS_PARSE_CTOS_SESSION_TICKET, ERR_R_INTERNAL_ERROR);
          return 0;
      }
  
      return 1;
  }
  
  int tls_parse_ctos_sig_algs_cert(SSL *s, PACKET *pkt, unsigned int context,
                                   X509 *x, size_t chainidx)
  {
      PACKET supported_sig_algs;
  
      if (!PACKET_as_length_prefixed_2(pkt, &supported_sig_algs)
              || PACKET_remaining(&supported_sig_algs) == 0) {
          SSLfatal(s, SSL_AD_DECODE_ERROR,
                   SSL_F_TLS_PARSE_CTOS_SIG_ALGS_CERT, SSL_R_BAD_EXTENSION);
          return 0;
      }
  
      if (!s->hit && !tls1_save_sigalgs(s, &supported_sig_algs, 1)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR,
                   SSL_F_TLS_PARSE_CTOS_SIG_ALGS_CERT, SSL_R_BAD_EXTENSION);
          return 0;
      }
  
      return 1;
  }
  
  int tls_parse_ctos_sig_algs(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
                              size_t chainidx)
  {
      PACKET supported_sig_algs;
  
      if (!PACKET_as_length_prefixed_2(pkt, &supported_sig_algs)
              || PACKET_remaining(&supported_sig_algs) == 0) {
          SSLfatal(s, SSL_AD_DECODE_ERROR,
                   SSL_F_TLS_PARSE_CTOS_SIG_ALGS, SSL_R_BAD_EXTENSION);
          return 0;
      }
  
      if (!s->hit && !tls1_save_sigalgs(s, &supported_sig_algs, 0)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR,
                   SSL_F_TLS_PARSE_CTOS_SIG_ALGS, SSL_R_BAD_EXTENSION);
          return 0;
      }
  
      return 1;
  }
  
  #ifndef OPENSSL_NO_OCSP
  int tls_parse_ctos_status_request(SSL *s, PACKET *pkt, unsigned int context,
                                    X509 *x, size_t chainidx)
  {
      PACKET responder_id_list, exts;
  
      /* Not defined if we get one of these in a client Certificate */
      if (x != NULL)
          return 1;
  
      if (!PACKET_get_1(pkt, (unsigned int *)&s->ext.status_type)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR,
                   SSL_F_TLS_PARSE_CTOS_STATUS_REQUEST, SSL_R_BAD_EXTENSION);
          return 0;
      }
  
      if (s->ext.status_type != TLSEXT_STATUSTYPE_ocsp) {
          /*
           * We don't know what to do with any other type so ignore it.
           */
          s->ext.status_type = TLSEXT_STATUSTYPE_nothing;
          return 1;
      }
  
      if (!PACKET_get_length_prefixed_2 (pkt, &responder_id_list)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR,
                   SSL_F_TLS_PARSE_CTOS_STATUS_REQUEST, SSL_R_BAD_EXTENSION);
          return 0;
      }
  
      /*
       * We remove any OCSP_RESPIDs from a previous handshake
       * to prevent unbounded memory growth - CVE-2016-6304
       */
      sk_OCSP_RESPID_pop_free(s->ext.ocsp.ids, OCSP_RESPID_free);
      if (PACKET_remaining(&responder_id_list) > 0) {
          s->ext.ocsp.ids = sk_OCSP_RESPID_new_null();
          if (s->ext.ocsp.ids == NULL) {
              SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                       SSL_F_TLS_PARSE_CTOS_STATUS_REQUEST, ERR_R_MALLOC_FAILURE);
              return 0;
          }
      } else {
          s->ext.ocsp.ids = NULL;
      }
  
      while (PACKET_remaining(&responder_id_list) > 0) {
          OCSP_RESPID *id;
          PACKET responder_id;
          const unsigned char *id_data;
  
          if (!PACKET_get_length_prefixed_2(&responder_id_list, &responder_id)
                  || PACKET_remaining(&responder_id) == 0) {
              SSLfatal(s, SSL_AD_DECODE_ERROR,
                       SSL_F_TLS_PARSE_CTOS_STATUS_REQUEST, SSL_R_BAD_EXTENSION);
              return 0;
          }
  
          id_data = PACKET_data(&responder_id);
          /* TODO(size_t): Convert d2i_* to size_t */
          id = d2i_OCSP_RESPID(NULL, &id_data,
                               (int)PACKET_remaining(&responder_id));
          if (id == NULL) {
              SSLfatal(s, SSL_AD_DECODE_ERROR,
                       SSL_F_TLS_PARSE_CTOS_STATUS_REQUEST, SSL_R_BAD_EXTENSION);
              return 0;
          }
  
          if (id_data != PACKET_end(&responder_id)) {
              OCSP_RESPID_free(id);
              SSLfatal(s, SSL_AD_DECODE_ERROR,
                       SSL_F_TLS_PARSE_CTOS_STATUS_REQUEST, SSL_R_BAD_EXTENSION);
  
              return 0;
          }
  
          if (!sk_OCSP_RESPID_push(s->ext.ocsp.ids, id)) {
              OCSP_RESPID_free(id);
              SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                       SSL_F_TLS_PARSE_CTOS_STATUS_REQUEST, ERR_R_INTERNAL_ERROR);
  
              return 0;
          }
      }
  
      /* Read in request_extensions */
      if (!PACKET_as_length_prefixed_2(pkt, &exts)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR,
                   SSL_F_TLS_PARSE_CTOS_STATUS_REQUEST, SSL_R_BAD_EXTENSION);
          return 0;
      }
  
      if (PACKET_remaining(&exts) > 0) {
          const unsigned char *ext_data = PACKET_data(&exts);
  
          sk_X509_EXTENSION_pop_free(s->ext.ocsp.exts,
                                     X509_EXTENSION_free);
          s->ext.ocsp.exts =
              d2i_X509_EXTENSIONS(NULL, &ext_data, (int)PACKET_remaining(&exts));
          if (s->ext.ocsp.exts == NULL || ext_data != PACKET_end(&exts)) {
              SSLfatal(s, SSL_AD_DECODE_ERROR,
                       SSL_F_TLS_PARSE_CTOS_STATUS_REQUEST, SSL_R_BAD_EXTENSION);
              return 0;
          }
      }
  
      return 1;
  }
  #endif
  
  #ifndef OPENSSL_NO_NEXTPROTONEG
  int tls_parse_ctos_npn(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
                         size_t chainidx)
  {
      /*
       * We shouldn't accept this extension on a
       * renegotiation.
       */
      if (SSL_IS_FIRST_HANDSHAKE(s))
          s->s3->npn_seen = 1;
  
      return 1;
  }
  #endif
  
  /*
   * Save the ALPN extension in a ClientHello.|pkt| holds the contents of the ALPN
   * extension, not including type and length. Returns: 1 on success, 0 on error.
   */
  int tls_parse_ctos_alpn(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
                          size_t chainidx)
  {
      PACKET protocol_list, save_protocol_list, protocol;
  
      if (!SSL_IS_FIRST_HANDSHAKE(s))
          return 1;
  
      if (!PACKET_as_length_prefixed_2(pkt, &protocol_list)
          || PACKET_remaining(&protocol_list) < 2) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_ALPN,
                   SSL_R_BAD_EXTENSION);
          return 0;
      }
  
      save_protocol_list = protocol_list;
      do {
          /* Protocol names can't be empty. */
          if (!PACKET_get_length_prefixed_1(&protocol_list, &protocol)
                  || PACKET_remaining(&protocol) == 0) {
              SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_ALPN,
                       SSL_R_BAD_EXTENSION);
              return 0;
          }
      } while (PACKET_remaining(&protocol_list) != 0);
  
      OPENSSL_free(s->s3->alpn_proposed);
      s->s3->alpn_proposed = NULL;
      s->s3->alpn_proposed_len = 0;
      if (!PACKET_memdup(&save_protocol_list,
                         &s->s3->alpn_proposed, &s->s3->alpn_proposed_len)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_ALPN,
                   ERR_R_INTERNAL_ERROR);
          return 0;
      }
  
      return 1;
  }
  
  #ifndef OPENSSL_NO_SRTP
  int tls_parse_ctos_use_srtp(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
                              size_t chainidx)
  {
      STACK_OF(SRTP_PROTECTION_PROFILE) *srvr;
      unsigned int ct, mki_len, id;
      int i, srtp_pref;
      PACKET subpkt;
  
      /* Ignore this if we have no SRTP profiles */
      if (SSL_get_srtp_profiles(s) == NULL)
          return 1;
  
      /* Pull off the length of the cipher suite list  and check it is even */
      if (!PACKET_get_net_2(pkt, &ct) || (ct & 1) != 0
              || !PACKET_get_sub_packet(pkt, &subpkt, ct)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_USE_SRTP,
                 SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
          return 0;
      }
  
      srvr = SSL_get_srtp_profiles(s);
      s->srtp_profile = NULL;
      /* Search all profiles for a match initially */
      srtp_pref = sk_SRTP_PROTECTION_PROFILE_num(srvr);
  
      while (PACKET_remaining(&subpkt)) {
          if (!PACKET_get_net_2(&subpkt, &id)) {
              SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_USE_SRTP,
                       SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
              return 0;
          }
  
          /*
           * Only look for match in profiles of higher preference than
           * current match.
           * If no profiles have been have been configured then this
           * does nothing.
           */
          for (i = 0; i < srtp_pref; i++) {
              SRTP_PROTECTION_PROFILE *sprof =
                  sk_SRTP_PROTECTION_PROFILE_value(srvr, i);
  
              if (sprof->id == id) {
                  s->srtp_profile = sprof;
                  srtp_pref = i;
                  break;
              }
          }
      }
  
      /* Now extract the MKI value as a sanity check, but discard it for now */
      if (!PACKET_get_1(pkt, &mki_len)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_USE_SRTP,
                   SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
          return 0;
      }
  
      if (!PACKET_forward(pkt, mki_len)
          || PACKET_remaining(pkt)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_USE_SRTP,
                   SSL_R_BAD_SRTP_MKI_VALUE);
          return 0;
      }
  
      return 1;
  }
  #endif
  
  int tls_parse_ctos_etm(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
                         size_t chainidx)
  {
      if (!(s->options & SSL_OP_NO_ENCRYPT_THEN_MAC))
          s->ext.use_etm = 1;
  
      return 1;
  }
  
  /*
   * Process a psk_kex_modes extension received in the ClientHello. |pkt| contains
   * the raw PACKET data for the extension. Returns 1 on success or 0 on failure.
   */
  int tls_parse_ctos_psk_kex_modes(SSL *s, PACKET *pkt, unsigned int context,
                                   X509 *x, size_t chainidx)
  {
  #ifndef OPENSSL_NO_TLS1_3
      PACKET psk_kex_modes;
      unsigned int mode;
  
      if (!PACKET_as_length_prefixed_1(pkt, &psk_kex_modes)
              || PACKET_remaining(&psk_kex_modes) == 0) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_PSK_KEX_MODES,
                   SSL_R_BAD_EXTENSION);
          return 0;
      }
  
      while (PACKET_get_1(&psk_kex_modes, &mode)) {
          if (mode == TLSEXT_KEX_MODE_KE_DHE)
              s->ext.psk_kex_mode |= TLSEXT_KEX_MODE_FLAG_KE_DHE;
          else if (mode == TLSEXT_KEX_MODE_KE
                  && (s->options & SSL_OP_ALLOW_NO_DHE_KEX) != 0)
              s->ext.psk_kex_mode |= TLSEXT_KEX_MODE_FLAG_KE;
      }
  #endif
  
      return 1;
  }
  
  /*
   * Process a key_share extension received in the ClientHello. |pkt| contains
   * the raw PACKET data for the extension. Returns 1 on success or 0 on failure.
   */
  int tls_parse_ctos_key_share(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
                               size_t chainidx)
  {
  #ifndef OPENSSL_NO_TLS1_3
      unsigned int group_id;
      PACKET key_share_list, encoded_pt;
      const uint16_t *clntgroups, *srvrgroups;
      size_t clnt_num_groups, srvr_num_groups;
      int found = 0;
  
      if (s->hit && (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE_DHE) == 0)
          return 1;
  
      /* Sanity check */
      if (s->s3->peer_tmp != NULL) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_KEY_SHARE,
                   ERR_R_INTERNAL_ERROR);
          return 0;
      }
  
      if (!PACKET_as_length_prefixed_2(pkt, &key_share_list)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_KEY_SHARE,
                   SSL_R_LENGTH_MISMATCH);
          return 0;
      }
  
      /* Get our list of supported groups */
      tls1_get_supported_groups(s, &srvrgroups, &srvr_num_groups);
      /* Get the clients list of supported groups. */
      tls1_get_peer_groups(s, &clntgroups, &clnt_num_groups);
      if (clnt_num_groups == 0) {
          /*
           * This can only happen if the supported_groups extension was not sent,
           * because we verify that the length is non-zero when we process that
           * extension.
           */
          SSLfatal(s, SSL_AD_MISSING_EXTENSION, SSL_F_TLS_PARSE_CTOS_KEY_SHARE,
                   SSL_R_MISSING_SUPPORTED_GROUPS_EXTENSION);
          return 0;
      }
  
      if (s->s3->group_id != 0 && PACKET_remaining(&key_share_list) == 0) {
          /*
           * If we set a group_id already, then we must have sent an HRR
           * requesting a new key_share. If we haven't got one then that is an
           * error
           */
          SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_CTOS_KEY_SHARE,
                   SSL_R_BAD_KEY_SHARE);
          return 0;
      }
  
      while (PACKET_remaining(&key_share_list) > 0) {
          if (!PACKET_get_net_2(&key_share_list, &group_id)
                  || !PACKET_get_length_prefixed_2(&key_share_list, &encoded_pt)
                  || PACKET_remaining(&encoded_pt) == 0) {
              SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_KEY_SHARE,
                       SSL_R_LENGTH_MISMATCH);
              return 0;
          }
  
          /*
           * If we already found a suitable key_share we loop through the
           * rest to verify the structure, but don't process them.
           */
          if (found)
              continue;
  
          /*
           * If we sent an HRR then the key_share sent back MUST be for the group
           * we requested, and must be the only key_share sent.
           */
          if (s->s3->group_id != 0
                  && (group_id != s->s3->group_id
                      || PACKET_remaining(&key_share_list) != 0)) {
              SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
                       SSL_F_TLS_PARSE_CTOS_KEY_SHARE, SSL_R_BAD_KEY_SHARE);
              return 0;
          }
  
          /* Check if this share is in supported_groups sent from client */
          if (!check_in_list(s, group_id, clntgroups, clnt_num_groups, 0)) {
              SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
                       SSL_F_TLS_PARSE_CTOS_KEY_SHARE, SSL_R_BAD_KEY_SHARE);
              return 0;
          }
  
          /* Check if this share is for a group we can use */
          if (!check_in_list(s, group_id, srvrgroups, srvr_num_groups, 1)) {
              /* Share not suitable */
              continue;
          }
  
          if ((s->s3->peer_tmp = ssl_generate_param_group(group_id)) == NULL) {
              SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_KEY_SHARE,
                     SSL_R_UNABLE_TO_FIND_ECDH_PARAMETERS);
              return 0;
          }
  
          s->s3->group_id = group_id;
  
          if (!EVP_PKEY_set1_tls_encodedpoint(s->s3->peer_tmp,
                  PACKET_data(&encoded_pt),
                  PACKET_remaining(&encoded_pt))) {
              SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
                       SSL_F_TLS_PARSE_CTOS_KEY_SHARE, SSL_R_BAD_ECPOINT);
              return 0;
          }
  
          found = 1;
      }
  #endif
  
      return 1;
  }
  
  int tls_parse_ctos_cookie(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
                            size_t chainidx)
  {
      unsigned int format, version, key_share, group_id;
      EVP_MD_CTX *hctx;
      EVP_PKEY *pkey;
      PACKET cookie, raw, chhash, appcookie;
      WPACKET hrrpkt;
      const unsigned char *data, *mdin, *ciphdata;
      unsigned char hmac[SHA256_DIGEST_LENGTH];
      unsigned char hrr[MAX_HRR_SIZE];
      size_t rawlen, hmaclen, hrrlen, ciphlen;
      unsigned long tm, now;
  
      /* Ignore any cookie if we're not set up to verify it */
      if (s->ctx->app_verify_cookie_cb == NULL
              || (s->s3->flags & TLS1_FLAGS_STATELESS) == 0)
          return 1;
  
      if (!PACKET_as_length_prefixed_2(pkt, &cookie)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
                   SSL_R_LENGTH_MISMATCH);
          return 0;
      }
  
      raw = cookie;
      data = PACKET_data(&raw);
      rawlen = PACKET_remaining(&raw);
      if (rawlen < SHA256_DIGEST_LENGTH
              || !PACKET_forward(&raw, rawlen - SHA256_DIGEST_LENGTH)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
                   SSL_R_LENGTH_MISMATCH);
          return 0;
      }
      mdin = PACKET_data(&raw);
  
      /* Verify the HMAC of the cookie */
      hctx = EVP_MD_CTX_create();
      pkey = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL,
                                  s->session_ctx->ext.cookie_hmac_key,
                                  sizeof(s->session_ctx->ext.cookie_hmac_key));
      if (hctx == NULL || pkey == NULL) {
          EVP_MD_CTX_free(hctx);
          EVP_PKEY_free(pkey);
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
                   ERR_R_MALLOC_FAILURE);
          return 0;
      }
  
      hmaclen = SHA256_DIGEST_LENGTH;
      if (EVP_DigestSignInit(hctx, NULL, EVP_sha256(), NULL, pkey) <= 0
              || EVP_DigestSign(hctx, hmac, &hmaclen, data,
                                rawlen - SHA256_DIGEST_LENGTH) <= 0
              || hmaclen != SHA256_DIGEST_LENGTH) {
          EVP_MD_CTX_free(hctx);
          EVP_PKEY_free(pkey);
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
                   ERR_R_INTERNAL_ERROR);
          return 0;
      }
  
      EVP_MD_CTX_free(hctx);
      EVP_PKEY_free(pkey);
  
      if (CRYPTO_memcmp(hmac, mdin, SHA256_DIGEST_LENGTH) != 0) {
          SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_CTOS_COOKIE,
                   SSL_R_COOKIE_MISMATCH);
          return 0;
      }
  
      if (!PACKET_get_net_2(&cookie, &format)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
                   SSL_R_LENGTH_MISMATCH);
          return 0;
      }
      /* Check the cookie format is something we recognise. Ignore it if not */
      if (format != COOKIE_STATE_FORMAT_VERSION)
          return 1;
  
      /*
       * The rest of these checks really shouldn't fail since we have verified the
       * HMAC above.
       */
  
      /* Check the version number is sane */
      if (!PACKET_get_net_2(&cookie, &version)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
                   SSL_R_LENGTH_MISMATCH);
          return 0;
      }
      if (version != TLS1_3_VERSION) {
          SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_CTOS_COOKIE,
                   SSL_R_BAD_PROTOCOL_VERSION_NUMBER);
          return 0;
      }
  
      if (!PACKET_get_net_2(&cookie, &group_id)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
                   SSL_R_LENGTH_MISMATCH);
          return 0;
      }
  
      ciphdata = PACKET_data(&cookie);
      if (!PACKET_forward(&cookie, 2)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
                   SSL_R_LENGTH_MISMATCH);
          return 0;
      }
      if (group_id != s->s3->group_id
              || s->s3->tmp.new_cipher
                 != ssl_get_cipher_by_char(s, ciphdata, 0)) {
          /*
           * We chose a different cipher or group id this time around to what is
           * in the cookie. Something must have changed.
           */
          SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_CTOS_COOKIE,
                   SSL_R_BAD_CIPHER);
          return 0;
      }
  
      if (!PACKET_get_1(&cookie, &key_share)
              || !PACKET_get_net_4(&cookie, &tm)
              || !PACKET_get_length_prefixed_2(&cookie, &chhash)
              || !PACKET_get_length_prefixed_1(&cookie, &appcookie)
              || PACKET_remaining(&cookie) != SHA256_DIGEST_LENGTH) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
                   SSL_R_LENGTH_MISMATCH);
          return 0;
      }
  
      /* We tolerate a cookie age of up to 10 minutes (= 60 * 10 seconds) */
      now = (unsigned long)time(NULL);
      if (tm > now || (now - tm) > 600) {
          /* Cookie is stale. Ignore it */
          return 1;
      }
  
      /* Verify the app cookie */
      if (s->ctx->app_verify_cookie_cb(s, PACKET_data(&appcookie),
                                       PACKET_remaining(&appcookie)) == 0) {
          SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_CTOS_COOKIE,
                   SSL_R_COOKIE_MISMATCH);
          return 0;
      }
  
      /*
       * Reconstruct the HRR that we would have sent in response to the original
       * ClientHello so we can add it to the transcript hash.
       * Note: This won't work with custom HRR extensions
       */
      if (!WPACKET_init_static_len(&hrrpkt, hrr, sizeof(hrr), 0)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
                   ERR_R_INTERNAL_ERROR);
          return 0;
      }
      if (!WPACKET_put_bytes_u8(&hrrpkt, SSL3_MT_SERVER_HELLO)
              || !WPACKET_start_sub_packet_u24(&hrrpkt)
              || !WPACKET_put_bytes_u16(&hrrpkt, TLS1_2_VERSION)
              || !WPACKET_memcpy(&hrrpkt, hrrrandom, SSL3_RANDOM_SIZE)
              || !WPACKET_sub_memcpy_u8(&hrrpkt, s->tmp_session_id,
                                        s->tmp_session_id_len)
              || !s->method->put_cipher_by_char(s->s3->tmp.new_cipher, &hrrpkt,
                                                &ciphlen)
              || !WPACKET_put_bytes_u8(&hrrpkt, 0)
              || !WPACKET_start_sub_packet_u16(&hrrpkt)) {
          WPACKET_cleanup(&hrrpkt);
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
                   ERR_R_INTERNAL_ERROR);
          return 0;
      }
      if (!WPACKET_put_bytes_u16(&hrrpkt, TLSEXT_TYPE_supported_versions)
              || !WPACKET_start_sub_packet_u16(&hrrpkt)
                 /* TODO(TLS1.3): Fix this before release */
              || !WPACKET_put_bytes_u16(&hrrpkt, TLS1_3_VERSION_DRAFT)
              || !WPACKET_close(&hrrpkt)) {
          WPACKET_cleanup(&hrrpkt);
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
                   ERR_R_INTERNAL_ERROR);
          return 0;
      }
      if (key_share) {
          if (!WPACKET_put_bytes_u16(&hrrpkt, TLSEXT_TYPE_key_share)
                  || !WPACKET_start_sub_packet_u16(&hrrpkt)
                  || !WPACKET_put_bytes_u16(&hrrpkt, s->s3->group_id)
                  || !WPACKET_close(&hrrpkt)) {
              WPACKET_cleanup(&hrrpkt);
              SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
                       ERR_R_INTERNAL_ERROR);
              return 0;
          }
      }
      if (!WPACKET_put_bytes_u16(&hrrpkt, TLSEXT_TYPE_cookie)
              || !WPACKET_start_sub_packet_u16(&hrrpkt)
              || !WPACKET_sub_memcpy_u16(&hrrpkt, data, rawlen)
              || !WPACKET_close(&hrrpkt) /* cookie extension */
              || !WPACKET_close(&hrrpkt) /* extension block */
              || !WPACKET_close(&hrrpkt) /* message */
              || !WPACKET_get_total_written(&hrrpkt, &hrrlen)
              || !WPACKET_finish(&hrrpkt)) {
          WPACKET_cleanup(&hrrpkt);
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
                   ERR_R_INTERNAL_ERROR);
          return 0;
      }
  
      /* Reconstruct the transcript hash */
      if (!create_synthetic_message_hash(s, PACKET_data(&chhash),
                                         PACKET_remaining(&chhash), hrr,
                                         hrrlen)) {
          /* SSLfatal() already called */
          return 0;
      }
  
      /* Act as if this ClientHello came after a HelloRetryRequest */
      s->hello_retry_request = 1;
  
      s->ext.cookieok = 1;
  
      return 1;
  }
  
  #ifndef OPENSSL_NO_EC
  int tls_parse_ctos_supported_groups(SSL *s, PACKET *pkt, unsigned int context,
                                      X509 *x, size_t chainidx)
  {
      PACKET supported_groups_list;
  
      /* Each group is 2 bytes and we must have at least 1. */
      if (!PACKET_as_length_prefixed_2(pkt, &supported_groups_list)
              || PACKET_remaining(&supported_groups_list) == 0
              || (PACKET_remaining(&supported_groups_list) % 2) != 0) {
          SSLfatal(s, SSL_AD_DECODE_ERROR,
                   SSL_F_TLS_PARSE_CTOS_SUPPORTED_GROUPS, SSL_R_BAD_EXTENSION);
          return 0;
      }
  
      if (!s->hit || SSL_IS_TLS13(s)) {
          OPENSSL_free(s->session->ext.supportedgroups);
          s->session->ext.supportedgroups = NULL;
          s->session->ext.supportedgroups_len = 0;
          if (!tls1_save_u16(&supported_groups_list,
                             &s->session->ext.supportedgroups,
                             &s->session->ext.supportedgroups_len)) {
              SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                       SSL_F_TLS_PARSE_CTOS_SUPPORTED_GROUPS,
                       ERR_R_INTERNAL_ERROR);
              return 0;
          }
      }
  
      return 1;
  }
  #endif
  
  int tls_parse_ctos_ems(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
                         size_t chainidx)
  {
      /* The extension must always be empty */
      if (PACKET_remaining(pkt) != 0) {
          SSLfatal(s, SSL_AD_DECODE_ERROR,
                   SSL_F_TLS_PARSE_CTOS_EMS, SSL_R_BAD_EXTENSION);
          return 0;
      }
  
      s->s3->flags |= TLS1_FLAGS_RECEIVED_EXTMS;
  
      return 1;
  }
  
  
  int tls_parse_ctos_early_data(SSL *s, PACKET *pkt, unsigned int context,
                                X509 *x, size_t chainidx)
  {
      if (PACKET_remaining(pkt) != 0) {
          SSLfatal(s, SSL_AD_DECODE_ERROR,
                   SSL_F_TLS_PARSE_CTOS_EARLY_DATA, SSL_R_BAD_EXTENSION);
          return 0;
      }
  
      if (s->hello_retry_request != SSL_HRR_NONE) {
          SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
                   SSL_F_TLS_PARSE_CTOS_EARLY_DATA, SSL_R_BAD_EXTENSION);
          return 0;
      }
  
      return 1;
  }
  
  int tls_parse_ctos_psk(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
                         size_t chainidx)
  {
      PACKET identities, binders, binder;
      size_t binderoffset, hashsize;
      SSL_SESSION *sess = NULL;
      unsigned int id, i, ext = 0;
      const EVP_MD *md = NULL;
  
      /*
       * If we have no PSK kex mode that we recognise then we can't resume so
       * ignore this extension
       */
      if ((s->ext.psk_kex_mode
              & (TLSEXT_KEX_MODE_FLAG_KE | TLSEXT_KEX_MODE_FLAG_KE_DHE)) == 0)
          return 1;
  
      if (!PACKET_get_length_prefixed_2(pkt, &identities)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR,
                   SSL_F_TLS_PARSE_CTOS_PSK, SSL_R_BAD_EXTENSION);
          return 0;
      }
  
      for (id = 0; PACKET_remaining(&identities) != 0; id++) {
          PACKET identity;
          unsigned long ticket_agel;
  
          if (!PACKET_get_length_prefixed_2(&identities, &identity)
                  || !PACKET_get_net_4(&identities, &ticket_agel)) {
              SSLfatal(s, SSL_AD_DECODE_ERROR,
                       SSL_F_TLS_PARSE_CTOS_PSK, SSL_R_BAD_EXTENSION);
              return 0;
          }
  
          if (s->psk_find_session_cb != NULL
                  && !s->psk_find_session_cb(s, PACKET_data(&identity),
                                             PACKET_remaining(&identity),
                                             &sess)) {
              SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                       SSL_F_TLS_PARSE_CTOS_PSK, SSL_R_BAD_EXTENSION);
              return 0;
          }
  
          if (sess != NULL) {
              /* We found a PSK */
              SSL_SESSION *sesstmp = ssl_session_dup(sess, 0);
  
              if (sesstmp == NULL) {
                  SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                           SSL_F_TLS_PARSE_CTOS_PSK, ERR_R_INTERNAL_ERROR);
                  return 0;
              }
              SSL_SESSION_free(sess);
              sess = sesstmp;
  
              /*
               * We've just been told to use this session for this context so
               * make sure the sid_ctx matches up.
               */
              memcpy(sess->sid_ctx, s->sid_ctx, s->sid_ctx_length);
              sess->sid_ctx_length = s->sid_ctx_length;
              ext = 1;
              if (id == 0)
                  s->ext.early_data_ok = 1;
          } else {
              uint32_t ticket_age = 0, now, agesec, agems;
              int ret = tls_decrypt_ticket(s, PACKET_data(&identity),
                                           PACKET_remaining(&identity), NULL, 0,
                                           &sess);
  
              if (ret == TICKET_FATAL_ERR_MALLOC
                      || ret == TICKET_FATAL_ERR_OTHER) {
                  SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                           SSL_F_TLS_PARSE_CTOS_PSK, ERR_R_INTERNAL_ERROR);
                  return 0;
              }
              if (ret == TICKET_NO_DECRYPT)
                  continue;
  
              ticket_age = (uint32_t)ticket_agel;
              now = (uint32_t)time(NULL);
              agesec = now - (uint32_t)sess->time;
              agems = agesec * (uint32_t)1000;
              ticket_age -= sess->ext.tick_age_add;
  
              /*
               * For simplicity we do our age calculations in seconds. If the
               * client does it in ms then it could appear that their ticket age
               * is longer than ours (our ticket age calculation should always be
               * slightly longer than the client's due to the network latency).
               * Therefore we add 1000ms to our age calculation to adjust for
               * rounding errors.
               */
              if (id == 0
                      && sess->timeout >= (long)agesec
                      && agems / (uint32_t)1000 == agesec
                      && ticket_age <= agems + 1000
                      && ticket_age + TICKET_AGE_ALLOWANCE >= agems + 1000) {
                  /*
                   * Ticket age is within tolerance and not expired. We allow it
                   * for early data
                   */
                  s->ext.early_data_ok = 1;
              }
          }
  
          md = ssl_md(sess->cipher->algorithm2);
          if (md != ssl_md(s->s3->tmp.new_cipher->algorithm2)) {
              /* The ciphersuite is not compatible with this session. */
              SSL_SESSION_free(sess);
              sess = NULL;
              s->ext.early_data_ok = 0;
              continue;
          }
          break;
      }
  
      if (sess == NULL)
          return 1;
  
      binderoffset = PACKET_data(pkt) - (const unsigned char *)s->init_buf->data;
      hashsize = EVP_MD_size(md);
  
      if (!PACKET_get_length_prefixed_2(pkt, &binders)) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_PSK,
                   SSL_R_BAD_EXTENSION);
          goto err;
      }
  
      for (i = 0; i <= id; i++) {
          if (!PACKET_get_length_prefixed_1(&binders, &binder)) {
              SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_PSK,
                       SSL_R_BAD_EXTENSION);
              goto err;
          }
      }
  
      if (PACKET_remaining(&binder) != hashsize) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_PSK,
                   SSL_R_BAD_EXTENSION);
          goto err;
      }
      if (tls_psk_do_binder(s, md, (const unsigned char *)s->init_buf->data,
                            binderoffset, PACKET_data(&binder), NULL, sess, 0,
                            ext) != 1) {
          /* SSLfatal() already called */
          goto err;
      }
  
      sess->ext.tick_identity = id;
  
      SSL_SESSION_free(s->session);
      s->session = sess;
      return 1;
  err:
      SSL_SESSION_free(sess);
      return 0;
  }
  
  int tls_parse_ctos_post_handshake_auth(SSL *s, PACKET *pkt, unsigned int context,
                                         X509 *x, size_t chainidx)
  {
      if (PACKET_remaining(pkt) != 0) {
          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_POST_HANDSHAKE_AUTH,
                   SSL_R_POST_HANDSHAKE_AUTH_ENCODING_ERR);
          return 0;
      }
  
      s->post_handshake_auth = SSL_PHA_EXT_RECEIVED;
  
      return 1;
  }
  
  /*
   * Add the server's renegotiation binding
   */
  EXT_RETURN tls_construct_stoc_renegotiate(SSL *s, WPACKET *pkt,
                                            unsigned int context, X509 *x,
                                            size_t chainidx)
  {
      if (!s->s3->send_connection_binding)
          return EXT_RETURN_NOT_SENT;
  
      /* Still add this even if SSL_OP_NO_RENEGOTIATION is set */
      if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_renegotiate)
              || !WPACKET_start_sub_packet_u16(pkt)
              || !WPACKET_start_sub_packet_u8(pkt)
              || !WPACKET_memcpy(pkt, s->s3->previous_client_finished,
                                 s->s3->previous_client_finished_len)
              || !WPACKET_memcpy(pkt, s->s3->previous_server_finished,
                                 s->s3->previous_server_finished_len)
              || !WPACKET_close(pkt)
              || !WPACKET_close(pkt)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_RENEGOTIATE,
                   ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      return EXT_RETURN_SENT;
  }
  
  EXT_RETURN tls_construct_stoc_server_name(SSL *s, WPACKET *pkt,
                                            unsigned int context, X509 *x,
                                            size_t chainidx)
  {
      if (s->hit || s->servername_done != 1
              || s->session->ext.hostname == NULL)
          return EXT_RETURN_NOT_SENT;
  
      if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_server_name)
              || !WPACKET_put_bytes_u16(pkt, 0)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_SERVER_NAME,
                   ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      return EXT_RETURN_SENT;
  }
  
  /* Add/include the server's max fragment len extension into ServerHello */
  EXT_RETURN tls_construct_stoc_maxfragmentlen(SSL *s, WPACKET *pkt,
                                               unsigned int context, X509 *x,
                                               size_t chainidx)
  {
      if (!USE_MAX_FRAGMENT_LENGTH_EXT(s->session))
          return EXT_RETURN_NOT_SENT;
  
      /*-
       * 4 bytes for this extension type and extension length
       * 1 byte for the Max Fragment Length code value.
       */
      if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_max_fragment_length)
          || !WPACKET_start_sub_packet_u16(pkt)
          || !WPACKET_put_bytes_u8(pkt, s->session->ext.max_fragment_len_mode)
          || !WPACKET_close(pkt)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                   SSL_F_TLS_CONSTRUCT_STOC_MAXFRAGMENTLEN, ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      return EXT_RETURN_SENT;
  }
  
  #ifndef OPENSSL_NO_EC
  EXT_RETURN tls_construct_stoc_ec_pt_formats(SSL *s, WPACKET *pkt,
                                              unsigned int context, X509 *x,
                                              size_t chainidx)
  {
      unsigned long alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
      unsigned long alg_a = s->s3->tmp.new_cipher->algorithm_auth;
      int using_ecc = ((alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA))
                      && (s->session->ext.ecpointformats != NULL);
      const unsigned char *plist;
      size_t plistlen;
  
      if (!using_ecc)
          return EXT_RETURN_NOT_SENT;
  
      tls1_get_formatlist(s, &plist, &plistlen);
      if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_ec_point_formats)
              || !WPACKET_start_sub_packet_u16(pkt)
              || !WPACKET_sub_memcpy_u8(pkt, plist, plistlen)
              || !WPACKET_close(pkt)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                   SSL_F_TLS_CONSTRUCT_STOC_EC_PT_FORMATS, ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      return EXT_RETURN_SENT;
  }
  #endif
  
  #ifndef OPENSSL_NO_EC
  EXT_RETURN tls_construct_stoc_supported_groups(SSL *s, WPACKET *pkt,
                                                 unsigned int context, X509 *x,
                                                 size_t chainidx)
  {
      const uint16_t *groups;
      size_t numgroups, i, first = 1;
  
      /* s->s3->group_id is non zero if we accepted a key_share */
      if (s->s3->group_id == 0)
          return EXT_RETURN_NOT_SENT;
  
      /* Get our list of supported groups */
      tls1_get_supported_groups(s, &groups, &numgroups);
      if (numgroups == 0) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                   SSL_F_TLS_CONSTRUCT_STOC_SUPPORTED_GROUPS, ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      /* Copy group ID if supported */
      for (i = 0; i < numgroups; i++) {
          uint16_t group = groups[i];
  
          if (tls_curve_allowed(s, group, SSL_SECOP_CURVE_SUPPORTED)) {
              if (first) {
                  /*
                   * Check if the client is already using our preferred group. If
                   * so we don't need to add this extension
                   */
                  if (s->s3->group_id == group)
                      return EXT_RETURN_NOT_SENT;
  
                  /* Add extension header */
                  if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_supported_groups)
                             /* Sub-packet for supported_groups extension */
                          || !WPACKET_start_sub_packet_u16(pkt)
                          || !WPACKET_start_sub_packet_u16(pkt)) {
                      SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                               SSL_F_TLS_CONSTRUCT_STOC_SUPPORTED_GROUPS,
                               ERR_R_INTERNAL_ERROR);
                      return EXT_RETURN_FAIL;
                  }
  
                  first = 0;
              }
              if (!WPACKET_put_bytes_u16(pkt, group)) {
                      SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                               SSL_F_TLS_CONSTRUCT_STOC_SUPPORTED_GROUPS,
                               ERR_R_INTERNAL_ERROR);
                      return EXT_RETURN_FAIL;
                  }
          }
      }
  
      if (!WPACKET_close(pkt) || !WPACKET_close(pkt)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                   SSL_F_TLS_CONSTRUCT_STOC_SUPPORTED_GROUPS,
                   ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      return EXT_RETURN_SENT;
  }
  #endif
  
  EXT_RETURN tls_construct_stoc_session_ticket(SSL *s, WPACKET *pkt,
                                               unsigned int context, X509 *x,
                                               size_t chainidx)
  {
      if (!s->ext.ticket_expected || !tls_use_ticket(s)) {
          s->ext.ticket_expected = 0;
          return EXT_RETURN_NOT_SENT;
      }
  
      if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_session_ticket)
              || !WPACKET_put_bytes_u16(pkt, 0)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                   SSL_F_TLS_CONSTRUCT_STOC_SESSION_TICKET, ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      return EXT_RETURN_SENT;
  }
  
  #ifndef OPENSSL_NO_OCSP
  EXT_RETURN tls_construct_stoc_status_request(SSL *s, WPACKET *pkt,
                                               unsigned int context, X509 *x,
                                               size_t chainidx)
  {
      if (!s->ext.status_expected)
          return EXT_RETURN_NOT_SENT;
  
      if (SSL_IS_TLS13(s) && chainidx != 0)
          return EXT_RETURN_NOT_SENT;
  
      if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_status_request)
              || !WPACKET_start_sub_packet_u16(pkt)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                   SSL_F_TLS_CONSTRUCT_STOC_STATUS_REQUEST, ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      /*
       * In TLSv1.3 we include the certificate status itself. In <= TLSv1.2 we
       * send back an empty extension, with the certificate status appearing as a
       * separate message
       */
      if (SSL_IS_TLS13(s) && !tls_construct_cert_status_body(s, pkt)) {
         /* SSLfatal() already called */
         return EXT_RETURN_FAIL;
      }
      if (!WPACKET_close(pkt)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                   SSL_F_TLS_CONSTRUCT_STOC_STATUS_REQUEST, ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      return EXT_RETURN_SENT;
  }
  #endif
  
  #ifndef OPENSSL_NO_NEXTPROTONEG
  EXT_RETURN tls_construct_stoc_next_proto_neg(SSL *s, WPACKET *pkt,
                                               unsigned int context, X509 *x,
                                               size_t chainidx)
  {
      const unsigned char *npa;
      unsigned int npalen;
      int ret;
      int npn_seen = s->s3->npn_seen;
  
      s->s3->npn_seen = 0;
      if (!npn_seen || s->ctx->ext.npn_advertised_cb == NULL)
          return EXT_RETURN_NOT_SENT;
  
      ret = s->ctx->ext.npn_advertised_cb(s, &npa, &npalen,
                                          s->ctx->ext.npn_advertised_cb_arg);
      if (ret == SSL_TLSEXT_ERR_OK) {
          if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_next_proto_neg)
                  || !WPACKET_sub_memcpy_u16(pkt, npa, npalen)) {
              SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                       SSL_F_TLS_CONSTRUCT_STOC_NEXT_PROTO_NEG,
                       ERR_R_INTERNAL_ERROR);
              return EXT_RETURN_FAIL;
          }
          s->s3->npn_seen = 1;
      }
  
      return EXT_RETURN_SENT;
  }
  #endif
  
  EXT_RETURN tls_construct_stoc_alpn(SSL *s, WPACKET *pkt, unsigned int context,
                                     X509 *x, size_t chainidx)
  {
      if (s->s3->alpn_selected == NULL)
          return EXT_RETURN_NOT_SENT;
  
      if (!WPACKET_put_bytes_u16(pkt,
                  TLSEXT_TYPE_application_layer_protocol_negotiation)
              || !WPACKET_start_sub_packet_u16(pkt)
              || !WPACKET_start_sub_packet_u16(pkt)
              || !WPACKET_sub_memcpy_u8(pkt, s->s3->alpn_selected,
                                        s->s3->alpn_selected_len)
              || !WPACKET_close(pkt)
              || !WPACKET_close(pkt)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                   SSL_F_TLS_CONSTRUCT_STOC_ALPN, ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      return EXT_RETURN_SENT;
  }
  
  #ifndef OPENSSL_NO_SRTP
  EXT_RETURN tls_construct_stoc_use_srtp(SSL *s, WPACKET *pkt,
                                         unsigned int context, X509 *x,
                                         size_t chainidx)
  {
      if (s->srtp_profile == NULL)
          return EXT_RETURN_NOT_SENT;
  
      if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_use_srtp)
              || !WPACKET_start_sub_packet_u16(pkt)
              || !WPACKET_put_bytes_u16(pkt, 2)
              || !WPACKET_put_bytes_u16(pkt, s->srtp_profile->id)
              || !WPACKET_put_bytes_u8(pkt, 0)
              || !WPACKET_close(pkt)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_USE_SRTP,
                   ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      return EXT_RETURN_SENT;
  }
  #endif
  
  EXT_RETURN tls_construct_stoc_etm(SSL *s, WPACKET *pkt, unsigned int context,
                                    X509 *x, size_t chainidx)
  {
      if (!s->ext.use_etm)
          return EXT_RETURN_NOT_SENT;
  
      /*
       * Don't use encrypt_then_mac if AEAD or RC4 might want to disable
       * for other cases too.
       */
      if (s->s3->tmp.new_cipher->algorithm_mac == SSL_AEAD
          || s->s3->tmp.new_cipher->algorithm_enc == SSL_RC4
          || s->s3->tmp.new_cipher->algorithm_enc == SSL_eGOST2814789CNT
          || s->s3->tmp.new_cipher->algorithm_enc == SSL_eGOST2814789CNT12) {
          s->ext.use_etm = 0;
          return EXT_RETURN_NOT_SENT;
      }
  
      if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_encrypt_then_mac)
              || !WPACKET_put_bytes_u16(pkt, 0)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_ETM,
                   ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      return EXT_RETURN_SENT;
  }
  
  EXT_RETURN tls_construct_stoc_ems(SSL *s, WPACKET *pkt, unsigned int context,
                                    X509 *x, size_t chainidx)
  {
      if ((s->s3->flags & TLS1_FLAGS_RECEIVED_EXTMS) == 0)
          return EXT_RETURN_NOT_SENT;
  
      if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_extended_master_secret)
              || !WPACKET_put_bytes_u16(pkt, 0)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_EMS,
                   ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      return EXT_RETURN_SENT;
  }
  
  EXT_RETURN tls_construct_stoc_supported_versions(SSL *s, WPACKET *pkt,
                                                   unsigned int context, X509 *x,
                                                   size_t chainidx)
  {
      if (!SSL_IS_TLS13(s))
          return EXT_RETURN_NOT_SENT;
  
      if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_supported_versions)
              || !WPACKET_start_sub_packet_u16(pkt)
                  /* TODO(TLS1.3): Update to remove the TLSv1.3 draft indicator */
              || !WPACKET_put_bytes_u16(pkt, TLS1_3_VERSION_DRAFT)
              || !WPACKET_close(pkt)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                   SSL_F_TLS_CONSTRUCT_STOC_SUPPORTED_VERSIONS,
                   ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      return EXT_RETURN_SENT;
  }
  
  EXT_RETURN tls_construct_stoc_key_share(SSL *s, WPACKET *pkt,
                                          unsigned int context, X509 *x,
                                          size_t chainidx)
  {
  #ifndef OPENSSL_NO_TLS1_3
      unsigned char *encodedPoint;
      size_t encoded_pt_len = 0;
      EVP_PKEY *ckey = s->s3->peer_tmp, *skey = NULL;
  
      if (s->hello_retry_request == SSL_HRR_PENDING) {
          if (ckey != NULL) {
              /* Original key_share was acceptable so don't ask for another one */
              return EXT_RETURN_NOT_SENT;
          }
          if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_key_share)
                  || !WPACKET_start_sub_packet_u16(pkt)
                  || !WPACKET_put_bytes_u16(pkt, s->s3->group_id)
                  || !WPACKET_close(pkt)) {
              SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                       SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE,
                       ERR_R_INTERNAL_ERROR);
              return EXT_RETURN_FAIL;
          }
  
          return EXT_RETURN_SENT;
      }
  
      if (ckey == NULL) {
          /* No key_share received from client - must be resuming */
          if (!s->hit || !tls13_generate_handshake_secret(s, NULL, 0)) {
              SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                       SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE, ERR_R_INTERNAL_ERROR);
              return EXT_RETURN_FAIL;
          }
          return EXT_RETURN_NOT_SENT;
      }
  
      if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_key_share)
              || !WPACKET_start_sub_packet_u16(pkt)
              || !WPACKET_put_bytes_u16(pkt, s->s3->group_id)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                   SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE, ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      skey = ssl_generate_pkey(ckey);
      if (skey == NULL) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE,
                   ERR_R_MALLOC_FAILURE);
          return EXT_RETURN_FAIL;
      }
  
      /* Generate encoding of server key */
      encoded_pt_len = EVP_PKEY_get1_tls_encodedpoint(skey, &encodedPoint);
      if (encoded_pt_len == 0) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE,
                   ERR_R_EC_LIB);
          EVP_PKEY_free(skey);
          return EXT_RETURN_FAIL;
      }
  
      if (!WPACKET_sub_memcpy_u16(pkt, encodedPoint, encoded_pt_len)
              || !WPACKET_close(pkt)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE,
                   ERR_R_INTERNAL_ERROR);
          EVP_PKEY_free(skey);
          OPENSSL_free(encodedPoint);
          return EXT_RETURN_FAIL;
      }
      OPENSSL_free(encodedPoint);
  
      /* This causes the crypto state to be updated based on the derived keys */
      s->s3->tmp.pkey = skey;
      if (ssl_derive(s, skey, ckey, 1) == 0) {
          /* SSLfatal() already called */
          return EXT_RETURN_FAIL;
      }
  #endif
  
      return EXT_RETURN_SENT;
  }
  
  EXT_RETURN tls_construct_stoc_cookie(SSL *s, WPACKET *pkt, unsigned int context,
                                       X509 *x, size_t chainidx)
  {
      unsigned char *hashval1, *hashval2, *appcookie1, *appcookie2, *cookie;
      unsigned char *hmac, *hmac2;
      size_t startlen, ciphlen, totcookielen, hashlen, hmaclen;
      unsigned int appcookielen;
      EVP_MD_CTX *hctx;
      EVP_PKEY *pkey;
      int ret = EXT_RETURN_FAIL;
  
      if (s->ctx->app_gen_cookie_cb == NULL
              || (s->s3->flags & TLS1_FLAGS_STATELESS) == 0)
          return EXT_RETURN_NOT_SENT;
  
      if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_cookie)
              || !WPACKET_start_sub_packet_u16(pkt)
              || !WPACKET_start_sub_packet_u16(pkt)
              || !WPACKET_get_total_written(pkt, &startlen)
              || !WPACKET_reserve_bytes(pkt, MAX_COOKIE_SIZE, &cookie)
              || !WPACKET_put_bytes_u16(pkt, COOKIE_STATE_FORMAT_VERSION)
              || !WPACKET_put_bytes_u16(pkt, TLS1_3_VERSION)
              || !WPACKET_put_bytes_u16(pkt, s->s3->group_id)
              || !s->method->put_cipher_by_char(s->s3->tmp.new_cipher, pkt,
                                                &ciphlen)
                 /* Is there a key_share extension present in this HRR? */
              || !WPACKET_put_bytes_u8(pkt, s->s3->peer_tmp == NULL)
              || !WPACKET_put_bytes_u32(pkt, (unsigned int)time(NULL))
              || !WPACKET_start_sub_packet_u16(pkt)
              || !WPACKET_reserve_bytes(pkt, EVP_MAX_MD_SIZE, &hashval1)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,
                   ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      /*
       * Get the hash of the initial ClientHello. ssl_handshake_hash() operates
       * on raw buffers, so we first reserve sufficient bytes (above) and then
       * subsequently allocate them (below)
       */
      if (!ssl3_digest_cached_records(s, 0)
              || !ssl_handshake_hash(s, hashval1, EVP_MAX_MD_SIZE, &hashlen)) {
          /* SSLfatal() already called */
          return EXT_RETURN_FAIL;
      }
  
      if (!WPACKET_allocate_bytes(pkt, hashlen, &hashval2)
              || !ossl_assert(hashval1 == hashval2)
              || !WPACKET_close(pkt)
              || !WPACKET_start_sub_packet_u8(pkt)
              || !WPACKET_reserve_bytes(pkt, SSL_COOKIE_LENGTH, &appcookie1)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,
                   ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      /* Generate the application cookie */
      if (s->ctx->app_gen_cookie_cb(s, appcookie1, &appcookielen) == 0) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,
                   SSL_R_COOKIE_GEN_CALLBACK_FAILURE);
          return EXT_RETURN_FAIL;
      }
  
      if (!WPACKET_allocate_bytes(pkt, appcookielen, &appcookie2)
              || !ossl_assert(appcookie1 == appcookie2)
              || !WPACKET_close(pkt)
              || !WPACKET_get_total_written(pkt, &totcookielen)
              || !WPACKET_reserve_bytes(pkt, SHA256_DIGEST_LENGTH, &hmac)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,
                   ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
      hmaclen = SHA256_DIGEST_LENGTH;
  
      totcookielen -= startlen;
      if (!ossl_assert(totcookielen <= MAX_COOKIE_SIZE - SHA256_DIGEST_LENGTH)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,
                   ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      /* HMAC the cookie */
      hctx = EVP_MD_CTX_create();
      pkey = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL,
                                  s->session_ctx->ext.cookie_hmac_key,
                                  sizeof(s->session_ctx->ext.cookie_hmac_key));
      if (hctx == NULL || pkey == NULL) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,
                   ERR_R_MALLOC_FAILURE);
          goto err;
      }
  
      if (EVP_DigestSignInit(hctx, NULL, EVP_sha256(), NULL, pkey) <= 0
              || EVP_DigestSign(hctx, hmac, &hmaclen, cookie,
                                totcookielen) <= 0) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,
                   ERR_R_INTERNAL_ERROR);
          goto err;
      }
  
      if (!ossl_assert(totcookielen + hmaclen <= MAX_COOKIE_SIZE)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,
                   ERR_R_INTERNAL_ERROR);
          goto err;
      }
  
      if (!WPACKET_allocate_bytes(pkt, hmaclen, &hmac2)
              || !ossl_assert(hmac == hmac2)
              || !ossl_assert(cookie == hmac - totcookielen)
              || !WPACKET_close(pkt)
              || !WPACKET_close(pkt)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,
                   ERR_R_INTERNAL_ERROR);
          goto err;
      }
  
      ret = EXT_RETURN_SENT;
  
   err:
      EVP_MD_CTX_free(hctx);
      EVP_PKEY_free(pkey);
      return ret;
  }
  
  EXT_RETURN tls_construct_stoc_cryptopro_bug(SSL *s, WPACKET *pkt,
                                              unsigned int context, X509 *x,
                                              size_t chainidx)
  {
      const unsigned char cryptopro_ext[36] = {
          0xfd, 0xe8,         /* 65000 */
          0x00, 0x20,         /* 32 bytes length */
          0x30, 0x1e, 0x30, 0x08, 0x06, 0x06, 0x2a, 0x85,
          0x03, 0x02, 0x02, 0x09, 0x30, 0x08, 0x06, 0x06,
          0x2a, 0x85, 0x03, 0x02, 0x02, 0x16, 0x30, 0x08,
          0x06, 0x06, 0x2a, 0x85, 0x03, 0x02, 0x02, 0x17
      };
  
      if (((s->s3->tmp.new_cipher->id & 0xFFFF) != 0x80
           && (s->s3->tmp.new_cipher->id & 0xFFFF) != 0x81)
              || (SSL_get_options(s) & SSL_OP_CRYPTOPRO_TLSEXT_BUG) == 0)
          return EXT_RETURN_NOT_SENT;
  
      if (!WPACKET_memcpy(pkt, cryptopro_ext, sizeof(cryptopro_ext))) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                   SSL_F_TLS_CONSTRUCT_STOC_CRYPTOPRO_BUG, ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      return EXT_RETURN_SENT;
  }
  
  EXT_RETURN tls_construct_stoc_early_data(SSL *s, WPACKET *pkt,
                                           unsigned int context, X509 *x,
                                           size_t chainidx)
  {
      if (context == SSL_EXT_TLS1_3_NEW_SESSION_TICKET) {
          if (s->max_early_data == 0)
              return EXT_RETURN_NOT_SENT;
  
          if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_early_data)
                  || !WPACKET_start_sub_packet_u16(pkt)
                  || !WPACKET_put_bytes_u32(pkt, s->max_early_data)
                  || !WPACKET_close(pkt)) {
              SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                       SSL_F_TLS_CONSTRUCT_STOC_EARLY_DATA, ERR_R_INTERNAL_ERROR);
              return EXT_RETURN_FAIL;
          }
  
          return EXT_RETURN_SENT;
      }
  
      if (s->ext.early_data != SSL_EARLY_DATA_ACCEPTED)
          return EXT_RETURN_NOT_SENT;
  
      if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_early_data)
              || !WPACKET_start_sub_packet_u16(pkt)
              || !WPACKET_close(pkt)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_EARLY_DATA,
                   ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      return EXT_RETURN_SENT;
  }
  
  EXT_RETURN tls_construct_stoc_psk(SSL *s, WPACKET *pkt, unsigned int context,
                                    X509 *x, size_t chainidx)
  {
      if (!s->hit)
          return EXT_RETURN_NOT_SENT;
  
      if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_psk)
              || !WPACKET_start_sub_packet_u16(pkt)
              || !WPACKET_put_bytes_u16(pkt, s->session->ext.tick_identity)
              || !WPACKET_close(pkt)) {
          SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                   SSL_F_TLS_CONSTRUCT_STOC_PSK, ERR_R_INTERNAL_ERROR);
          return EXT_RETURN_FAIL;
      }
  
      return EXT_RETURN_SENT;
  }
  