/src/hostap/src/tls/tlsv1_server_write.c

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/*
 * TLSv1 server - write handshake message
 * Copyright (c) 2006-2014, Jouni Malinen <j@w1.fi>
 *
 * This software may be distributed under the terms of the BSD license.
 * See README for more details.
 */

#include "includes.h"

#include "common.h"
#include "crypto/md5.h"
#include "crypto/sha1.h"
#include "crypto/sha256.h"
#include "crypto/tls.h"
#include "crypto/random.h"
#include "x509v3.h"
#include "tlsv1_common.h"
#include "tlsv1_record.h"
#include "tlsv1_server.h"
#include "tlsv1_server_i.h"


static size_t tls_server_cert_chain_der_len(struct tlsv1_server *conn)
{
  size_t len = 0;
  struct x509_certificate *cert;

  cert = conn->cred ? conn->cred->cert : NULL;
  while (cert) {
    len += 3 + cert->cert_len;
    if (x509_certificate_self_signed(cert))
      break;
    cert = x509_certificate_get_subject(conn->cred->trusted_certs,
                &cert->issuer);
  }

  return len;
}


static int tls_write_server_hello(struct tlsv1_server *conn,
          u8 **msgpos, u8 *end)
{
  u8 *pos, *rhdr, *hs_start, *hs_length, *ext_start;
  struct os_time now;
  size_t rlen;

  pos = *msgpos;

  tlsv1_server_log(conn, "Send ServerHello");
  rhdr = pos;
  pos += TLS_RECORD_HEADER_LEN;

  os_get_time(&now);
#ifdef TEST_FUZZ
  now.sec = 0xfffefdfc;
#endif /* TEST_FUZZ */
  WPA_PUT_BE32(conn->server_random, now.sec);
  if (random_get_bytes(conn->server_random + 4, TLS_RANDOM_LEN - 4)) {
    wpa_printf(MSG_ERROR, "TLSv1: Could not generate "
         "server_random");
    return -1;
  }
  wpa_hexdump(MSG_MSGDUMP, "TLSv1: server_random",
        conn->server_random, TLS_RANDOM_LEN);

  conn->session_id_len = TLS_SESSION_ID_MAX_LEN;
  if (random_get_bytes(conn->session_id, conn->session_id_len)) {
    wpa_printf(MSG_ERROR, "TLSv1: Could not generate "
         "session_id");
    return -1;
  }
  wpa_hexdump(MSG_MSGDUMP, "TLSv1: session_id",
        conn->session_id, conn->session_id_len);

  /* opaque fragment[TLSPlaintext.length] */

  /* Handshake */
  hs_start = pos;
  /* HandshakeType msg_type */
  *pos++ = TLS_HANDSHAKE_TYPE_SERVER_HELLO;
  /* uint24 length (to be filled) */
  hs_length = pos;
  pos += 3;
  /* body - ServerHello */
  /* ProtocolVersion server_version */
  WPA_PUT_BE16(pos, conn->rl.tls_version);
  pos += 2;
  /* Random random: uint32 gmt_unix_time, opaque random_bytes */
  os_memcpy(pos, conn->server_random, TLS_RANDOM_LEN);
  pos += TLS_RANDOM_LEN;
  /* SessionID session_id */
  *pos++ = conn->session_id_len;
  os_memcpy(pos, conn->session_id, conn->session_id_len);
  pos += conn->session_id_len;
  /* CipherSuite cipher_suite */
  WPA_PUT_BE16(pos, conn->cipher_suite);
  pos += 2;
  /* CompressionMethod compression_method */
  *pos++ = TLS_COMPRESSION_NULL;

  /* Extension */
  ext_start = pos;
  pos += 2;

  if (conn->status_request) {
    /* Add a status_request extension with empty extension_data */
    /* ExtensionsType extension_type = status_request(5) */
    WPA_PUT_BE16(pos, TLS_EXT_STATUS_REQUEST);
    pos += 2;
    /* opaque extension_data<0..2^16-1> length */
    WPA_PUT_BE16(pos, 0);
    pos += 2;
  }

  if (conn->status_request_v2) {
    /*
      Add a status_request_v2 extension with empty extension_data
    */
    /* ExtensionsType extension_type = status_request_v2(17) */
    WPA_PUT_BE16(pos, TLS_EXT_STATUS_REQUEST_V2);
    pos += 2;
    /* opaque extension_data<0..2^16-1> length */
    WPA_PUT_BE16(pos, 0);
    pos += 2;
  }

  if (conn->session_ticket && conn->session_ticket_cb) {
    int res = conn->session_ticket_cb(
      conn->session_ticket_cb_ctx,
      conn->session_ticket, conn->session_ticket_len,
      conn->client_random, conn->server_random,
      conn->master_secret);
    if (res < 0) {
      tlsv1_server_log(conn, "SessionTicket callback indicated failure");
      tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
             TLS_ALERT_HANDSHAKE_FAILURE);
      return -1;
    }
    conn->use_session_ticket = res;

    if (conn->use_session_ticket) {
      if (tlsv1_server_derive_keys(conn, NULL, 0) < 0) {
        wpa_printf(MSG_DEBUG, "TLSv1: Failed to "
             "derive keys");
        tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
               TLS_ALERT_INTERNAL_ERROR);
        return -1;
      }
    }

    /*
     * RFC 4507 specifies that server would include an empty
     * SessionTicket extension in ServerHello and a
     * NewSessionTicket message after the ServerHello. However,
     * EAP-FAST (RFC 4851), i.e., the only user of SessionTicket
     * extension at the moment, does not use such extensions.
     *
     * TODO: Add support for configuring RFC 4507 behavior and make
     * EAP-FAST disable it.
     */
  }

  if (pos == ext_start + 2)
    pos -= 2; /* no extensions */
  else
    WPA_PUT_BE16(ext_start, pos - ext_start - 2);

  WPA_PUT_BE24(hs_length, pos - hs_length - 3);
  tls_verify_hash_add(&conn->verify, hs_start, pos - hs_start);

  if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
            rhdr, end - rhdr, hs_start, pos - hs_start,
            &rlen) < 0) {
    wpa_printf(MSG_DEBUG, "TLSv1: Failed to create TLS record");
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }
  pos = rhdr + rlen;

  *msgpos = pos;

  return 0;
}


static int tls_write_server_certificate(struct tlsv1_server *conn,
          u8 **msgpos, u8 *end)
{
  u8 *pos, *rhdr, *hs_start, *hs_length, *cert_start;
  size_t rlen;
  struct x509_certificate *cert;
  const struct tls_cipher_suite *suite;

  suite = tls_get_cipher_suite(conn->rl.cipher_suite);
  if (suite && suite->key_exchange == TLS_KEY_X_DH_anon) {
    wpa_printf(MSG_DEBUG, "TLSv1: Do not send Certificate when "
         "using anonymous DH");
    return 0;
  }

  pos = *msgpos;
  if (TLS_RECORD_HEADER_LEN + 1 + 3 + 3 > end - pos) {
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }

  tlsv1_server_log(conn, "Send Certificate");
  rhdr = pos;
  pos += TLS_RECORD_HEADER_LEN;

  /* opaque fragment[TLSPlaintext.length] */

  /* Handshake */
  hs_start = pos;
  /* HandshakeType msg_type */
  *pos++ = TLS_HANDSHAKE_TYPE_CERTIFICATE;
  /* uint24 length (to be filled) */
  hs_length = pos;
  pos += 3;
  /* body - Certificate */
  /* uint24 length (to be filled) */
  cert_start = pos;
  pos += 3;
  cert = conn->cred->cert;
  while (cert) {
    if (3 + cert->cert_len > (size_t) (end - pos)) {
      wpa_printf(MSG_DEBUG, "TLSv1: Not enough buffer space "
           "for Certificate (cert_len=%lu left=%lu)",
           (unsigned long) cert->cert_len,
           (unsigned long) (end - pos));
      tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
             TLS_ALERT_INTERNAL_ERROR);
      return -1;
    }
    WPA_PUT_BE24(pos, cert->cert_len);
    pos += 3;
    os_memcpy(pos, cert->cert_start, cert->cert_len);
    pos += cert->cert_len;

    if (x509_certificate_self_signed(cert))
      break;
    cert = x509_certificate_get_subject(conn->cred->trusted_certs,
                &cert->issuer);
  }
  if (cert == conn->cred->cert || cert == NULL) {
    /*
     * Server was not configured with all the needed certificates
     * to form a full certificate chain. The client may fail to
     * validate the chain unless it is configured with all the
     * missing CA certificates.
     */
    wpa_printf(MSG_DEBUG, "TLSv1: Full server certificate chain "
         "not configured - validation may fail");
  }
  WPA_PUT_BE24(cert_start, pos - cert_start - 3);

  WPA_PUT_BE24(hs_length, pos - hs_length - 3);

  if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
            rhdr, end - rhdr, hs_start, pos - hs_start,
            &rlen) < 0) {
    wpa_printf(MSG_DEBUG, "TLSv1: Failed to generate a record");
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }
  pos = rhdr + rlen;

  tls_verify_hash_add(&conn->verify, hs_start, pos - hs_start);

  *msgpos = pos;

  return 0;
}


static int tls_write_server_certificate_status(struct tlsv1_server *conn,
                 u8 **msgpos, u8 *end,
                 int ocsp_multi,
                 char *ocsp_resp,
                 size_t ocsp_resp_len)
{
  u8 *pos, *rhdr, *hs_start, *hs_length;
  size_t rlen;

  if (!ocsp_resp) {
     /*
      * Client did not request certificate status or there is no
      * matching response cached.
      */
    return 0;
  }

  pos = *msgpos;
  if (TLS_RECORD_HEADER_LEN + 1 + 3 + 1 + 3 + ocsp_resp_len >
      (unsigned int) (end - pos)) {
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }

  tlsv1_server_log(conn, "Send CertificateStatus (multi=%d)", ocsp_multi);
  rhdr = pos;
  pos += TLS_RECORD_HEADER_LEN;

  /* opaque fragment[TLSPlaintext.length] */

  /* Handshake */
  hs_start = pos;
  /* HandshakeType msg_type */
  *pos++ = TLS_HANDSHAKE_TYPE_CERTIFICATE_STATUS;
  /* uint24 length (to be filled) */
  hs_length = pos;
  pos += 3;

  /* body - CertificateStatus
   *
   * struct {
   *     CertificateStatusType status_type;
   *     select (status_type) {
   *         case ocsp: OCSPResponse;
   *         case ocsp_multi: OCSPResponseList;
   *     } response;
   * } CertificateStatus;
   *
   * opaque OCSPResponse<1..2^24-1>;
   *
   * struct {
   *   OCSPResponse ocsp_response_list<1..2^24-1>;
   * } OCSPResponseList;
   */

  /* CertificateStatusType status_type */
  if (ocsp_multi)
    *pos++ = 2; /* ocsp_multi(2) */
  else
    *pos++ = 1; /* ocsp(1) */
  /* uint24 length of OCSPResponse */
  WPA_PUT_BE24(pos, ocsp_resp_len);
  pos += 3;
  os_memcpy(pos, ocsp_resp, ocsp_resp_len);
  pos += ocsp_resp_len;

  WPA_PUT_BE24(hs_length, pos - hs_length - 3);

  if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
            rhdr, end - rhdr, hs_start, pos - hs_start,
            &rlen) < 0) {
    wpa_printf(MSG_DEBUG, "TLSv1: Failed to generate a record");
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }
  pos = rhdr + rlen;

  tls_verify_hash_add(&conn->verify, hs_start, pos - hs_start);

  *msgpos = pos;

  return 0;
}


static int tls_write_server_key_exchange(struct tlsv1_server *conn,
           u8 **msgpos, u8 *end)
{
  tls_key_exchange keyx;
  const struct tls_cipher_suite *suite;
  u8 *pos, *rhdr, *hs_start, *hs_length, *server_params;
  size_t rlen;
  u8 *dh_ys;
  size_t dh_ys_len;
  const u8 *dh_p;
  size_t dh_p_len;

  suite = tls_get_cipher_suite(conn->rl.cipher_suite);
  if (suite == NULL)
    keyx = TLS_KEY_X_NULL;
  else
    keyx = suite->key_exchange;

  if (!tls_server_key_exchange_allowed(conn->rl.cipher_suite)) {
    wpa_printf(MSG_DEBUG, "TLSv1: No ServerKeyExchange needed");
    return 0;
  }

  if (keyx != TLS_KEY_X_DH_anon && keyx != TLS_KEY_X_DHE_RSA) {
    wpa_printf(MSG_DEBUG, "TLSv1: ServerKeyExchange not yet "
         "supported with key exchange type %d", keyx);
    return -1;
  }

  if (conn->cred == NULL || conn->cred->dh_p == NULL ||
      conn->cred->dh_g == NULL) {
    wpa_printf(MSG_DEBUG, "TLSv1: No DH parameters available for "
         "ServerKeyExhcange");
    return -1;
  }

  tlsv1_server_get_dh_p(conn, &dh_p, &dh_p_len);

  os_free(conn->dh_secret);
  conn->dh_secret_len = dh_p_len;
  conn->dh_secret = os_malloc(conn->dh_secret_len);
  if (conn->dh_secret == NULL) {
    wpa_printf(MSG_DEBUG, "TLSv1: Failed to allocate "
         "memory for secret (Diffie-Hellman)");
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }
  if (random_get_bytes(conn->dh_secret, conn->dh_secret_len)) {
    wpa_printf(MSG_DEBUG, "TLSv1: Failed to get random "
         "data for Diffie-Hellman");
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    os_free(conn->dh_secret);
    conn->dh_secret = NULL;
    return -1;
  }

  if (os_memcmp(conn->dh_secret, dh_p, conn->dh_secret_len) > 0)
    conn->dh_secret[0] = 0; /* make sure secret < p */

  pos = conn->dh_secret;
  while (pos + 1 < conn->dh_secret + conn->dh_secret_len && *pos == 0)
    pos++;
  if (pos != conn->dh_secret) {
    os_memmove(conn->dh_secret, pos,
         conn->dh_secret_len - (pos - conn->dh_secret));
    conn->dh_secret_len -= pos - conn->dh_secret;
  }
  wpa_hexdump_key(MSG_DEBUG, "TLSv1: DH server's secret value",
      conn->dh_secret, conn->dh_secret_len);

  /* Ys = g^secret mod p */
  dh_ys_len = dh_p_len;
  dh_ys = os_malloc(dh_ys_len);
  if (dh_ys == NULL) {
    wpa_printf(MSG_DEBUG, "TLSv1: Failed to allocate memory for "
         "Diffie-Hellman");
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }
  if (crypto_mod_exp(conn->cred->dh_g, conn->cred->dh_g_len,
         conn->dh_secret, conn->dh_secret_len,
         dh_p, dh_p_len, dh_ys, &dh_ys_len)) {
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    os_free(dh_ys);
    return -1;
  }

  wpa_hexdump(MSG_DEBUG, "TLSv1: DH Ys (server's public value)",
        dh_ys, dh_ys_len);

  /*
   * struct {
   *    select (KeyExchangeAlgorithm) {
   *       case diffie_hellman:
   *          ServerDHParams params;
   *          Signature signed_params;
   *       case rsa:
   *          ServerRSAParams params;
   *          Signature signed_params;
   *    };
   * } ServerKeyExchange;
   *
   * struct {
   *    opaque dh_p<1..2^16-1>;
   *    opaque dh_g<1..2^16-1>;
   *    opaque dh_Ys<1..2^16-1>;
   * } ServerDHParams;
   */

  pos = *msgpos;

  tlsv1_server_log(conn, "Send ServerKeyExchange");
  rhdr = pos;
  pos += TLS_RECORD_HEADER_LEN;

  /* opaque fragment[TLSPlaintext.length] */

  /* Handshake */
  hs_start = pos;
  /* HandshakeType msg_type */
  *pos++ = TLS_HANDSHAKE_TYPE_SERVER_KEY_EXCHANGE;
  /* uint24 length (to be filled) */
  hs_length = pos;
  pos += 3;

  /* body - ServerDHParams */
  server_params = pos;
  /* dh_p */
  if (2 + dh_p_len > (size_t) (end - pos)) {
    wpa_printf(MSG_DEBUG, "TLSv1: Not enough buffer space for "
         "dh_p");
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    os_free(dh_ys);
    return -1;
  }
  WPA_PUT_BE16(pos, dh_p_len);
  pos += 2;
  os_memcpy(pos, dh_p, dh_p_len);
  pos += dh_p_len;

  /* dh_g */
  if (2 + conn->cred->dh_g_len > (size_t) (end - pos)) {
    wpa_printf(MSG_DEBUG, "TLSv1: Not enough buffer space for "
         "dh_g");
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    os_free(dh_ys);
    return -1;
  }
  WPA_PUT_BE16(pos, conn->cred->dh_g_len);
  pos += 2;
  os_memcpy(pos, conn->cred->dh_g, conn->cred->dh_g_len);
  pos += conn->cred->dh_g_len;

  /* dh_Ys */
  if (2 + dh_ys_len > (size_t) (end - pos)) {
    wpa_printf(MSG_DEBUG, "TLSv1: Not enough buffer space for "
         "dh_Ys");
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    os_free(dh_ys);
    return -1;
  }
  WPA_PUT_BE16(pos, dh_ys_len);
  pos += 2;
  os_memcpy(pos, dh_ys, dh_ys_len);
  pos += dh_ys_len;
  os_free(dh_ys);

  /*
   * select (SignatureAlgorithm)
   * {   case anonymous: struct { };
   *     case rsa:
   *         digitally-signed struct {
   *             opaque md5_hash[16];
   *             opaque sha_hash[20];
   *         };
   *     case dsa:
   *         digitally-signed struct {
   *             opaque sha_hash[20];
   *         };
   * } Signature;
   *
   * md5_hash
   *     MD5(ClientHello.random + ServerHello.random + ServerParams);
   *
   * sha_hash
   *     SHA(ClientHello.random + ServerHello.random + ServerParams);
   */

  if (keyx == TLS_KEY_X_DHE_RSA) {
    u8 hash[100];
    u8 *signed_start;
    size_t clen;
    int hlen;

    if (conn->rl.tls_version >= TLS_VERSION_1_2) {
#ifdef CONFIG_TLSV12
      hlen = tlsv12_key_x_server_params_hash(
        conn->rl.tls_version, TLS_HASH_ALG_SHA256,
        conn->client_random,
        conn->server_random, server_params,
        pos - server_params, hash + 19);

      /*
       * RFC 5246, 4.7:
       * TLS v1.2 adds explicit indication of the used
       * signature and hash algorithms.
       *
       * struct {
       *   HashAlgorithm hash;
       *   SignatureAlgorithm signature;
       * } SignatureAndHashAlgorithm;
       */
      if (hlen < 0 || end - pos < 2) {
        tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
               TLS_ALERT_INTERNAL_ERROR);
        return -1;
      }
      *pos++ = TLS_HASH_ALG_SHA256;
      *pos++ = TLS_SIGN_ALG_RSA;

      /*
       * RFC 3447, A.2.4 RSASSA-PKCS1-v1_5
       *
       * DigestInfo ::= SEQUENCE {
       *   digestAlgorithm DigestAlgorithm,
       *   digest OCTET STRING
       * }
       *
       * SHA-256 OID: sha256WithRSAEncryption ::= {pkcs-1 11}
       *
       * DER encoded DigestInfo for SHA256 per RFC 3447:
       * 30 31 30 0d 06 09 60 86 48 01 65 03 04 02 01 05 00
       * 04 20 || H
       */
      hlen += 19;
      os_memcpy(hash,
          "\x30\x31\x30\x0d\x06\x09\x60\x86\x48\x01\x65"
          "\x03\x04\x02\x01\x05\x00\x04\x20", 19);

#else /* CONFIG_TLSV12 */
      tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
             TLS_ALERT_INTERNAL_ERROR);
      return -1;
#endif /* CONFIG_TLSV12 */
    } else {
      hlen = tls_key_x_server_params_hash(
        conn->rl.tls_version, conn->client_random,
        conn->server_random, server_params,
        pos - server_params, hash, sizeof(hash));
    }

    if (hlen < 0) {
      tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
             TLS_ALERT_INTERNAL_ERROR);
      return -1;
    }

    wpa_hexdump(MSG_MSGDUMP, "TLS: ServerKeyExchange signed_params hash",
          hash, hlen);
#ifdef CONFIG_TESTING_OPTIONS
    if (conn->test_flags & TLS_BREAK_SRV_KEY_X_HASH) {
      tlsv1_server_log(conn, "TESTING: Break ServerKeyExchange signed params hash");
      hash[hlen - 1] ^= 0x80;
    }
#endif /* CONFIG_TESTING_OPTIONS */

    /*
     * RFC 2246, 4.7:
     * In digital signing, one-way hash functions are used as input
     * for a signing algorithm. A digitally-signed element is
     * encoded as an opaque vector <0..2^16-1>, where the length is
     * specified by the signing algorithm and key.
     *
     * In RSA signing, a 36-byte structure of two hashes (one SHA
     * and one MD5) is signed (encrypted with the private key). It
     * is encoded with PKCS #1 block type 0 or type 1 as described
     * in [PKCS1].
     */
    signed_start = pos; /* length to be filled */
    pos += 2;
    clen = end - pos;
    if (conn->cred == NULL ||
        crypto_private_key_sign_pkcs1(conn->cred->key, hash, hlen,
              pos, &clen) < 0) {
      wpa_printf(MSG_DEBUG, "TLSv1: Failed to sign hash (PKCS #1)");
      tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
             TLS_ALERT_INTERNAL_ERROR);
      return -1;
    }
    WPA_PUT_BE16(signed_start, clen);
#ifdef CONFIG_TESTING_OPTIONS
    if (conn->test_flags & TLS_BREAK_SRV_KEY_X_SIGNATURE) {
      tlsv1_server_log(conn, "TESTING: Break ServerKeyExchange signed params signature");
      pos[clen - 1] ^= 0x80;
    }
#endif /* CONFIG_TESTING_OPTIONS */

    pos += clen;
  }

  WPA_PUT_BE24(hs_length, pos - hs_length - 3);

  if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
            rhdr, end - rhdr, hs_start, pos - hs_start,
            &rlen) < 0) {
    wpa_printf(MSG_DEBUG, "TLSv1: Failed to generate a record");
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }
  pos = rhdr + rlen;

  tls_verify_hash_add(&conn->verify, hs_start, pos - hs_start);

  *msgpos = pos;

  return 0;
}


static int tls_write_server_certificate_request(struct tlsv1_server *conn,
            u8 **msgpos, u8 *end)
{
  u8 *pos, *rhdr, *hs_start, *hs_length;
  size_t rlen;

  if (!conn->verify_peer) {
    wpa_printf(MSG_DEBUG, "TLSv1: No CertificateRequest needed");
    return 0;
  }

  pos = *msgpos;

  tlsv1_server_log(conn, "Send CertificateRequest");
  rhdr = pos;
  pos += TLS_RECORD_HEADER_LEN;

  /* opaque fragment[TLSPlaintext.length] */

  /* Handshake */
  hs_start = pos;
  /* HandshakeType msg_type */
  *pos++ = TLS_HANDSHAKE_TYPE_CERTIFICATE_REQUEST;
  /* uint24 length (to be filled) */
  hs_length = pos;
  pos += 3;
  /* body - CertificateRequest */

  /*
   * enum {
   *   rsa_sign(1), dss_sign(2), rsa_fixed_dh(3), dss_fixed_dh(4),
   *   (255)
   * } ClientCertificateType;
   * ClientCertificateType certificate_types<1..2^8-1>
   */
  *pos++ = 1;
  *pos++ = 1; /* rsa_sign */

  /*
   * opaque DistinguishedName<1..2^16-1>
   * DistinguishedName certificate_authorities<3..2^16-1>
   */
  /* TODO: add support for listing DNs for trusted CAs */
  WPA_PUT_BE16(pos, 0);
  pos += 2;

  WPA_PUT_BE24(hs_length, pos - hs_length - 3);

  if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
            rhdr, end - rhdr, hs_start, pos - hs_start,
            &rlen) < 0) {
    wpa_printf(MSG_DEBUG, "TLSv1: Failed to generate a record");
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }
  pos = rhdr + rlen;

  tls_verify_hash_add(&conn->verify, hs_start, pos - hs_start);

  *msgpos = pos;

  return 0;
}


static int tls_write_server_hello_done(struct tlsv1_server *conn,
               u8 **msgpos, u8 *end)
{
  u8 *pos;
  size_t rlen;
  u8 payload[4];

  tlsv1_server_log(conn, "Send ServerHelloDone");

  /* opaque fragment[TLSPlaintext.length] */

  /* Handshake */
  pos = payload;
  /* HandshakeType msg_type */
  *pos++ = TLS_HANDSHAKE_TYPE_SERVER_HELLO_DONE;
  /* uint24 length */
  WPA_PUT_BE24(pos, 0);
  pos += 3;
  /* body - ServerHelloDone (empty) */

  if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
            *msgpos, end - *msgpos, payload, pos - payload,
            &rlen) < 0) {
    wpa_printf(MSG_DEBUG, "TLSv1: Failed to generate a record");
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }

  tls_verify_hash_add(&conn->verify, payload, pos - payload);

  *msgpos += rlen;

  return 0;
}


static int tls_write_server_change_cipher_spec(struct tlsv1_server *conn,
                 u8 **msgpos, u8 *end)
{
  size_t rlen;
  u8 payload[1];

  tlsv1_server_log(conn, "Send ChangeCipherSpec");

  payload[0] = TLS_CHANGE_CIPHER_SPEC;

  if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_CHANGE_CIPHER_SPEC,
            *msgpos, end - *msgpos, payload, sizeof(payload),
            &rlen) < 0) {
    wpa_printf(MSG_DEBUG, "TLSv1: Failed to create a record");
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }

  if (tlsv1_record_change_write_cipher(&conn->rl) < 0) {
    wpa_printf(MSG_DEBUG, "TLSv1: Failed to set write cipher for "
         "record layer");
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }

  *msgpos += rlen;

  return 0;
}


static int tls_write_server_finished(struct tlsv1_server *conn,
             u8 **msgpos, u8 *end)
{
  u8 *pos, *hs_start;
  size_t rlen, hlen;
  u8 verify_data[1 + 3 + TLS_VERIFY_DATA_LEN];
  u8 hash[MD5_MAC_LEN + SHA1_MAC_LEN];

  pos = *msgpos;

  tlsv1_server_log(conn, "Send Finished");

  /* Encrypted Handshake Message: Finished */

#ifdef CONFIG_TLSV12
  if (conn->rl.tls_version >= TLS_VERSION_1_2) {
    hlen = SHA256_MAC_LEN;
    if (conn->verify.sha256_server == NULL ||
        crypto_hash_finish(conn->verify.sha256_server, hash, &hlen)
        < 0) {
      conn->verify.sha256_server = NULL;
      tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
             TLS_ALERT_INTERNAL_ERROR);
      return -1;
    }
    conn->verify.sha256_server = NULL;
  } else {
#endif /* CONFIG_TLSV12 */

  hlen = MD5_MAC_LEN;
  if (conn->verify.md5_server == NULL ||
      crypto_hash_finish(conn->verify.md5_server, hash, &hlen) < 0) {
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    conn->verify.md5_server = NULL;
    crypto_hash_finish(conn->verify.sha1_server, NULL, NULL);
    conn->verify.sha1_server = NULL;
    return -1;
  }
  conn->verify.md5_server = NULL;
  hlen = SHA1_MAC_LEN;
  if (conn->verify.sha1_server == NULL ||
      crypto_hash_finish(conn->verify.sha1_server, hash + MD5_MAC_LEN,
             &hlen) < 0) {
    conn->verify.sha1_server = NULL;
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }
  conn->verify.sha1_server = NULL;
  hlen = MD5_MAC_LEN + SHA1_MAC_LEN;

#ifdef CONFIG_TLSV12
  }
#endif /* CONFIG_TLSV12 */

  if (tls_prf(conn->rl.tls_version,
        conn->master_secret, TLS_MASTER_SECRET_LEN,
        "server finished", hash, hlen,
        verify_data + 1 + 3, TLS_VERIFY_DATA_LEN)) {
    wpa_printf(MSG_DEBUG, "TLSv1: Failed to generate verify_data");
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }
  wpa_hexdump_key(MSG_DEBUG, "TLSv1: verify_data (server)",
      verify_data + 1 + 3, TLS_VERIFY_DATA_LEN);
#ifdef CONFIG_TESTING_OPTIONS
  if (conn->test_flags & TLS_BREAK_VERIFY_DATA) {
    tlsv1_server_log(conn, "TESTING: Break verify_data (server)");
    verify_data[1 + 3 + 1] ^= 0x80;
  }
#endif /* CONFIG_TESTING_OPTIONS */

  /* Handshake */
  pos = hs_start = verify_data;
  /* HandshakeType msg_type */
  *pos++ = TLS_HANDSHAKE_TYPE_FINISHED;
  /* uint24 length */
  WPA_PUT_BE24(pos, TLS_VERIFY_DATA_LEN);
  pos += 3;
  pos += TLS_VERIFY_DATA_LEN;
  tls_verify_hash_add(&conn->verify, hs_start, pos - hs_start);

  if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
            *msgpos, end - *msgpos, hs_start, pos - hs_start,
            &rlen) < 0) {
    wpa_printf(MSG_DEBUG, "TLSv1: Failed to create a record");
    tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
           TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }

  *msgpos += rlen;

  return 0;
}


static u8 * tls_send_server_hello(struct tlsv1_server *conn, size_t *out_len)
{
  u8 *msg, *end, *pos;
  size_t msglen;
  int ocsp_multi = 0;
  char *ocsp_resp = NULL;
  size_t ocsp_resp_len = 0;

  *out_len = 0;

  if (conn->status_request_multi &&
      conn->cred->ocsp_stapling_response_multi) {
    ocsp_resp = os_readfile(
      conn->cred->ocsp_stapling_response_multi,
      &ocsp_resp_len);
    ocsp_multi = 1;
  } else if ((conn->status_request || conn->status_request_v2) &&
       conn->cred->ocsp_stapling_response) {
    ocsp_resp = os_readfile(conn->cred->ocsp_stapling_response,
          &ocsp_resp_len);
  }
  if (!ocsp_resp)
    ocsp_resp_len = 0;

  msglen = 1000 + tls_server_cert_chain_der_len(conn) + ocsp_resp_len;

  msg = os_malloc(msglen);
  if (msg == NULL) {
    os_free(ocsp_resp);
    return NULL;
  }

  pos = msg;
  end = msg + msglen;

  if (tls_write_server_hello(conn, &pos, end) < 0) {
    os_free(msg);
    os_free(ocsp_resp);
    return NULL;
  }

  if (conn->use_session_ticket) {
    os_free(ocsp_resp);

    /* Abbreviated handshake using session ticket; RFC 4507 */
    if (tls_write_server_change_cipher_spec(conn, &pos, end) < 0 ||
        tls_write_server_finished(conn, &pos, end) < 0) {
      os_free(msg);
      return NULL;
    }

    *out_len = pos - msg;

    conn->state = CHANGE_CIPHER_SPEC;

    return msg;
  }

  /* Full handshake */
  if (tls_write_server_certificate(conn, &pos, end) < 0 ||
      tls_write_server_certificate_status(conn, &pos, end, ocsp_multi,
            ocsp_resp, ocsp_resp_len) < 0 ||
      tls_write_server_key_exchange(conn, &pos, end) < 0 ||
      tls_write_server_certificate_request(conn, &pos, end) < 0 ||
      tls_write_server_hello_done(conn, &pos, end) < 0) {
    os_free(msg);
    os_free(ocsp_resp);
    return NULL;
  }
  os_free(ocsp_resp);

  *out_len = pos - msg;

  conn->state = CLIENT_CERTIFICATE;

  return msg;
}


static u8 * tls_send_change_cipher_spec(struct tlsv1_server *conn,
          size_t *out_len)
{
  u8 *msg, *end, *pos;

  *out_len = 0;

  msg = os_malloc(1000);
  if (msg == NULL)
    return NULL;

  pos = msg;
  end = msg + 1000;

  if (tls_write_server_change_cipher_spec(conn, &pos, end) < 0 ||
      tls_write_server_finished(conn, &pos, end) < 0) {
    os_free(msg);
    return NULL;
  }

  *out_len = pos - msg;

  tlsv1_server_log(conn, "Handshake completed successfully");
  conn->state = ESTABLISHED;

  return msg;
}


u8 * tlsv1_server_handshake_write(struct tlsv1_server *conn, size_t *out_len)
{
  switch (conn->state) {
  case SERVER_HELLO:
    return tls_send_server_hello(conn, out_len);
  case SERVER_CHANGE_CIPHER_SPEC:
    return tls_send_change_cipher_spec(conn, out_len);
  default:
    if (conn->state == ESTABLISHED && conn->use_session_ticket) {
      /* Abbreviated handshake was already completed. */
      return NULL;
    }
    tlsv1_server_log(conn, "Unexpected state %d while generating reply",
         conn->state);
    return NULL;
  }
}


u8 * tlsv1_server_send_alert(struct tlsv1_server *conn, u8 level,
           u8 description, size_t *out_len)
{
  u8 *alert, *pos, *length;

  tlsv1_server_log(conn, "Send Alert(%d:%d)", level, description);
  *out_len = 0;

  alert = os_malloc(10);
  if (alert == NULL)
    return NULL;

  pos = alert;

  /* TLSPlaintext */
  /* ContentType type */
  *pos++ = TLS_CONTENT_TYPE_ALERT;
  /* ProtocolVersion version */
  WPA_PUT_BE16(pos, conn->rl.tls_version ? conn->rl.tls_version :
         TLS_VERSION);
  pos += 2;
  /* uint16 length (to be filled) */
  length = pos;
  pos += 2;
  /* opaque fragment[TLSPlaintext.length] */

  /* Alert */
  /* AlertLevel level */
  *pos++ = level;
  /* AlertDescription description */
  *pos++ = description;

  WPA_PUT_BE16(length, pos - length - 2);
  *out_len = pos - alert;

  return alert;
}

Coverage Report

Created: 2025-04-24 06:18