/src/hostap/src/tls/tlsv1_client_write.c

Source
/*
 * TLSv1 client - write handshake message
 * Copyright (c) 2006-2015, 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_client.h"
#include "tlsv1_client_i.h"


static size_t tls_client_cert_chain_der_len(struct tlsv1_client *conn)
{
  size_t len = 0;
  struct x509_certificate *cert;

  if (conn->cred == NULL)
    return 0;

  cert = conn->cred->cert;
  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;
}


u8 * tls_send_client_hello(struct tlsv1_client *conn, size_t *out_len)
{
  u8 *hello, *end, *pos, *hs_length, *hs_start, *rhdr;
  struct os_time now;
  size_t len, i;
  u8 *ext_start;
  u16 tls_version = tls_client_highest_ver(conn);

  if (!tls_version) {
    wpa_printf(MSG_INFO, "TLSv1: No TLS version allowed");
    return NULL;
  }

  wpa_printf(MSG_DEBUG, "TLSv1: Send ClientHello (ver %s)",
       tls_version_str(tls_version));
  *out_len = 0;

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

  len = 150 + conn->num_cipher_suites * 2 + conn->client_hello_ext_len;
  hello = os_malloc(len);
  if (hello == NULL)
    return NULL;
  end = hello + len;

  rhdr = hello;
  pos = rhdr + TLS_RECORD_HEADER_LEN;

  /* opaque fragment[TLSPlaintext.length] */

  /* Handshake */
  hs_start = pos;
  /* HandshakeType msg_type */
  *pos++ = TLS_HANDSHAKE_TYPE_CLIENT_HELLO;
  /* uint24 length (to be filled) */
  hs_length = pos;
  pos += 3;
  /* body - ClientHello */
  /* ProtocolVersion client_version */
  WPA_PUT_BE16(pos, tls_version);
  pos += 2;
  /* Random random: uint32 gmt_unix_time, opaque random_bytes */
  os_memcpy(pos, conn->client_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_suites<2..2^16-1> */
  WPA_PUT_BE16(pos, 2 * conn->num_cipher_suites);
  pos += 2;
  for (i = 0; i < conn->num_cipher_suites; i++) {
    WPA_PUT_BE16(pos, conn->cipher_suites[i]);
    pos += 2;
  }
  /* CompressionMethod compression_methods<1..2^8-1> */
  *pos++ = 1;
  *pos++ = TLS_COMPRESSION_NULL;

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

#ifdef CONFIG_TLSV12
  if (conn->rl.tls_version >= TLS_VERSION_1_2) {
    /*
     * Add signature_algorithms extension since we support only
     * SHA256 (and not the default SHA1) with TLSv1.2.
     */
    /* ExtensionsType extension_type = signature_algorithms(13) */
    WPA_PUT_BE16(pos, TLS_EXT_SIGNATURE_ALGORITHMS);
    pos += 2;
    /* opaque extension_data<0..2^16-1> length */
    WPA_PUT_BE16(pos, 8);
    pos += 2;
    /* supported_signature_algorithms<2..2^16-2> length */
    WPA_PUT_BE16(pos, 6);
    pos += 2;
    /* supported_signature_algorithms */
    *pos++ = TLS_HASH_ALG_SHA512;
    *pos++ = TLS_SIGN_ALG_RSA;
    *pos++ = TLS_HASH_ALG_SHA384;
    *pos++ = TLS_SIGN_ALG_RSA;
    *pos++ = TLS_HASH_ALG_SHA256;
    *pos++ = TLS_SIGN_ALG_RSA;
  }
#endif /* CONFIG_TLSV12 */

  if (conn->client_hello_ext) {
    os_memcpy(pos, conn->client_hello_ext,
        conn->client_hello_ext_len);
    pos += conn->client_hello_ext_len;
  }

  if (conn->flags & TLS_CONN_REQUEST_OCSP) {
    wpa_printf(MSG_DEBUG,
         "TLSv1: Add status_request extension for OCSP stapling");
    /* 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, 5);
    pos += 2;

    /*
     * RFC 6066, 8:
     * struct {
     *     CertificateStatusType status_type;
     *     select (status_type) {
     *         case ocsp: OCSPStatusRequest;
     *     } request;
     * } CertificateStatusRequest;
     *
     * enum { ocsp(1), (255) } CertificateStatusType;
     */
    *pos++ = 1; /* status_type = ocsp(1) */

    /*
     * struct {
     *     ResponderID responder_id_list<0..2^16-1>;
     *     Extensions  request_extensions;
     * } OCSPStatusRequest;
     *
     * opaque ResponderID<1..2^16-1>;
     * opaque Extensions<0..2^16-1>;
     */
    WPA_PUT_BE16(pos, 0); /* responder_id_list(empty) */
    pos += 2;
    WPA_PUT_BE16(pos, 0); /* request_extensions(empty) */
    pos += 2;

    wpa_printf(MSG_DEBUG,
         "TLSv1: Add status_request_v2 extension for OCSP stapling");
    /* 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, 7);
    pos += 2;

    /*
     * RFC 6961, 2.2:
     * struct {
     *     CertificateStatusType status_type;
     *     uint16 request_length;
     *     select (status_type) {
     *         case ocsp: OCSPStatusRequest;
     *         case ocsp_multi: OCSPStatusRequest;
     *     } request;
     * } CertificateStatusRequestItemV2;
     *
     * enum { ocsp(1), ocsp_multi(2), (255) } CertificateStatusType;
     *
     * struct {
     * CertificateStatusRequestItemV2
     *     certificate_status_req_list<1..2^16-1>;
     * } CertificateStatusRequestListV2;
     */

    /* certificate_status_req_list<1..2^16-1> */
    WPA_PUT_BE16(pos, 5);
    pos += 2;

    /* CertificateStatusRequestItemV2 */
    *pos++ = 2; /* status_type = ocsp_multi(2) */
    /* OCSPStatusRequest as shown above for v1 */
    WPA_PUT_BE16(pos, 0); /* responder_id_list(empty) */
    pos += 2;
    WPA_PUT_BE16(pos, 0); /* request_extensions(empty) */
    pos += 2;
  }

  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,
            out_len) < 0) {
    wpa_printf(MSG_DEBUG, "TLSv1: Failed to create TLS record");
    tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
        TLS_ALERT_INTERNAL_ERROR);
    os_free(hello);
    return NULL;
  }

  conn->state = SERVER_HELLO;

  return hello;
}


static int tls_write_client_certificate(struct tlsv1_client *conn,
          u8 **msgpos, u8 *end)
{
  u8 *pos, *rhdr, *hs_start, *hs_length, *cert_start;
  size_t rlen;
  struct x509_certificate *cert;

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

  wpa_printf(MSG_DEBUG, "TLSv1: 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 ? conn->cred->cert : NULL;
  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));
      tls_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 (conn->cred == NULL || cert == conn->cred->cert || cert == NULL) {
    /*
     * Client was not configured with all the needed certificates
     * to form a full certificate chain. The server may fail to
     * validate the chain unless it is configured with all the
     * missing CA certificates.
     */
    wpa_printf(MSG_DEBUG, "TLSv1: Full client 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");
    tls_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 tlsv1_key_x_dh(struct tlsv1_client *conn, u8 **pos, u8 *end)
{
  /* ClientDiffieHellmanPublic */
  u8 *csecret, *csecret_start, *dh_yc, *shared;
  size_t csecret_len, dh_yc_len, shared_len;

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

  if (os_memcmp(csecret, conn->dh_p, csecret_len) > 0)
    csecret[0] = 0; /* make sure Yc < p */

  csecret_start = csecret;
  while (csecret_len > 1 && *csecret_start == 0) {
    csecret_start++;
    csecret_len--;
  }
  wpa_hexdump_key(MSG_DEBUG, "TLSv1: DH client's secret value",
      csecret_start, csecret_len);

  /* Yc = g^csecret mod p */
  dh_yc_len = conn->dh_p_len;
  dh_yc = os_malloc(dh_yc_len);
  if (dh_yc == NULL) {
    wpa_printf(MSG_DEBUG, "TLSv1: Failed to allocate "
         "memory for Diffie-Hellman");
    tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
        TLS_ALERT_INTERNAL_ERROR);
    os_free(csecret);
    return -1;
  }
  if (crypto_mod_exp(conn->dh_g, conn->dh_g_len,
         csecret_start, csecret_len,
         conn->dh_p, conn->dh_p_len,
         dh_yc, &dh_yc_len)) {
    tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
        TLS_ALERT_INTERNAL_ERROR);
    os_free(csecret);
    os_free(dh_yc);
    return -1;
  }

  wpa_hexdump(MSG_DEBUG, "TLSv1: DH Yc (client's public value)",
        dh_yc, dh_yc_len);

  if (end - *pos < 2) {
    tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
        TLS_ALERT_INTERNAL_ERROR);
    os_free(csecret);
    os_free(dh_yc);
    return -1;
  }
  WPA_PUT_BE16(*pos, dh_yc_len);
  *pos += 2;
  if (dh_yc_len > (size_t) (end - *pos)) {
    wpa_printf(MSG_DEBUG, "TLSv1: Not enough room in the "
         "message buffer for Yc");
    tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
        TLS_ALERT_INTERNAL_ERROR);
    os_free(csecret);
    os_free(dh_yc);
    return -1;
  }
  os_memcpy(*pos, dh_yc, dh_yc_len);
  *pos += dh_yc_len;
  os_free(dh_yc);

  shared_len = conn->dh_p_len;
  shared = os_malloc(shared_len);
  if (shared == NULL) {
    wpa_printf(MSG_DEBUG, "TLSv1: Could not allocate memory for "
         "DH");
    tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
        TLS_ALERT_INTERNAL_ERROR);
    os_free(csecret);
    return -1;
  }

  /* shared = Ys^csecret mod p */
  if (crypto_mod_exp(conn->dh_ys, conn->dh_ys_len,
         csecret_start, csecret_len,
         conn->dh_p, conn->dh_p_len,
         shared, &shared_len)) {
    tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
        TLS_ALERT_INTERNAL_ERROR);
    os_free(csecret);
    os_free(shared);
    return -1;
  }
  wpa_hexdump_key(MSG_DEBUG, "TLSv1: Shared secret from DH key exchange",
      shared, shared_len);

  os_memset(csecret_start, 0, csecret_len);
  os_free(csecret);
  if (tls_derive_keys(conn, shared, shared_len)) {
    wpa_printf(MSG_DEBUG, "TLSv1: Failed to derive keys");
    tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
        TLS_ALERT_INTERNAL_ERROR);
    os_free(shared);
    return -1;
  }
  os_memset(shared, 0, shared_len);
  os_free(shared);
  tlsv1_client_free_dh(conn);
  return 0;
}


static int tlsv1_key_x_rsa(struct tlsv1_client *conn, u8 **pos, u8 *end)
{
  u8 pre_master_secret[TLS_PRE_MASTER_SECRET_LEN];
  size_t clen;
  int res;

  if (tls_derive_pre_master_secret(conn, pre_master_secret) < 0 ||
      tls_derive_keys(conn, pre_master_secret,
          TLS_PRE_MASTER_SECRET_LEN)) {
    wpa_printf(MSG_DEBUG, "TLSv1: Failed to derive keys");
    tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
        TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }

  /* EncryptedPreMasterSecret */
  if (conn->server_rsa_key == NULL) {
    wpa_printf(MSG_DEBUG, "TLSv1: No server RSA key to "
         "use for encrypting pre-master secret");
    tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
        TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }

  /* RSA encrypted value is encoded with PKCS #1 v1.5 block type 2. */
  *pos += 2;
  clen = end - *pos;
  res = crypto_public_key_encrypt_pkcs1_v15(
    conn->server_rsa_key,
    pre_master_secret, TLS_PRE_MASTER_SECRET_LEN,
    *pos, &clen);
  os_memset(pre_master_secret, 0, TLS_PRE_MASTER_SECRET_LEN);
  if (res < 0) {
    wpa_printf(MSG_DEBUG, "TLSv1: RSA encryption failed");
    tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
        TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }
  WPA_PUT_BE16(*pos - 2, clen);
  wpa_hexdump(MSG_MSGDUMP, "TLSv1: Encrypted pre_master_secret",
        *pos, clen);
  *pos += clen;

  return 0;
}


static int tls_write_client_key_exchange(struct tlsv1_client *conn,
           u8 **msgpos, u8 *end)
{
  u8 *pos, *rhdr, *hs_start, *hs_length;
  size_t rlen;
  tls_key_exchange keyx;
  const struct tls_cipher_suite *suite;

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

  pos = *msgpos;

  wpa_printf(MSG_DEBUG, "TLSv1: Send ClientKeyExchange");

  rhdr = pos;
  pos += TLS_RECORD_HEADER_LEN;

  /* opaque fragment[TLSPlaintext.length] */

  /* Handshake */
  hs_start = pos;
  /* HandshakeType msg_type */
  *pos++ = TLS_HANDSHAKE_TYPE_CLIENT_KEY_EXCHANGE;
  /* uint24 length (to be filled) */
  hs_length = pos;
  pos += 3;
  /* body - ClientKeyExchange */
  if (keyx == TLS_KEY_X_DH_anon || keyx == TLS_KEY_X_DHE_RSA) {
    if (tlsv1_key_x_dh(conn, &pos, end) < 0)
      return -1;
  } else {
    if (tlsv1_key_x_rsa(conn, &pos, end) < 0)
      return -1;
  }

  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 create a record");
    tls_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_client_certificate_verify(struct tlsv1_client *conn,
                 u8 **msgpos, u8 *end)
{
  u8 *pos, *rhdr, *hs_start, *hs_length, *signed_start;
  size_t rlen, hlen, clen;
  u8 hash[100], *hpos;

  pos = *msgpos;

  wpa_printf(MSG_DEBUG, "TLSv1: Send CertificateVerify");
  rhdr = pos;
  pos += TLS_RECORD_HEADER_LEN;

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

  /*
   * RFC 2246: 7.4.3 and 7.4.8:
   * Signature signature
   *
   * RSA:
   * digitally-signed struct {
   *     opaque md5_hash[16];
   *     opaque sha_hash[20];
   * };
   *
   * DSA:
   * digitally-signed struct {
   *     opaque sha_hash[20];
   * };
   *
   * The hash values are calculated over all handshake messages sent or
   * received starting at ClientHello up to, but not including, this
   * CertificateVerify message, including the type and length fields of
   * the handshake messages.
   */

  hpos = hash;

#ifdef CONFIG_TLSV12
  if (conn->rl.tls_version == TLS_VERSION_1_2) {
    hlen = SHA256_MAC_LEN;
    if (conn->verify.sha256_cert == NULL ||
        crypto_hash_finish(conn->verify.sha256_cert, hpos, &hlen) <
        0) {
      conn->verify.sha256_cert = NULL;
      tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
          TLS_ALERT_INTERNAL_ERROR);
      return -1;
    }
    conn->verify.sha256_cert = NULL;

    /*
     * 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
     */
    os_memmove(hash + 19, hash, hlen);
    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 {
#endif /* CONFIG_TLSV12 */

  hlen = MD5_MAC_LEN;
  if (conn->verify.md5_cert == NULL ||
      crypto_hash_finish(conn->verify.md5_cert, hpos, &hlen) < 0) {
    tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
        TLS_ALERT_INTERNAL_ERROR);
    conn->verify.md5_cert = NULL;
    crypto_hash_finish(conn->verify.sha1_cert, NULL, NULL);
    conn->verify.sha1_cert = NULL;
    return -1;
  }
  hpos += MD5_MAC_LEN;

  conn->verify.md5_cert = NULL;
  hlen = SHA1_MAC_LEN;
  if (conn->verify.sha1_cert == NULL ||
      crypto_hash_finish(conn->verify.sha1_cert, hpos, &hlen) < 0) {
    conn->verify.sha1_cert = NULL;
    tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
        TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }
  conn->verify.sha1_cert = NULL;

  hlen += MD5_MAC_LEN;

#ifdef CONFIG_TLSV12
  }
#endif /* CONFIG_TLSV12 */

  wpa_hexdump(MSG_MSGDUMP, "TLSv1: CertificateVerify hash", hash, hlen);

#ifdef CONFIG_TLSV12
  if (conn->rl.tls_version >= TLS_VERSION_1_2) {
    /*
     * RFC 5246, 4.7:
     * TLS v1.2 adds explicit indication of the used signature and
     * hash algorithms.
     *
     * struct {
     *   HashAlgorithm hash;
     *   SignatureAlgorithm signature;
     * } SignatureAndHashAlgorithm;
     */
    *pos++ = TLS_HASH_ALG_SHA256;
    *pos++ = TLS_SIGN_ALG_RSA;
  }
#endif /* CONFIG_TLSV12 */

  /*
   * 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)");
    tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
        TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }
  WPA_PUT_BE16(signed_start, clen);

  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");
    tls_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_client_change_cipher_spec(struct tlsv1_client *conn,
                 u8 **msgpos, u8 *end)
{
  size_t rlen;
  u8 payload[1];

  wpa_printf(MSG_DEBUG, "TLSv1: 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");
    tls_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");
    tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
        TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }

  *msgpos += rlen;

  return 0;
}


static int tls_write_client_finished(struct tlsv1_client *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];

  wpa_printf(MSG_DEBUG, "TLSv1: 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_client == NULL ||
        crypto_hash_finish(conn->verify.sha256_client, hash, &hlen)
        < 0) {
      tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
          TLS_ALERT_INTERNAL_ERROR);
      conn->verify.sha256_client = NULL;
      return -1;
    }
    conn->verify.sha256_client = NULL;
  } else {
#endif /* CONFIG_TLSV12 */

  hlen = MD5_MAC_LEN;
  if (conn->verify.md5_client == NULL ||
      crypto_hash_finish(conn->verify.md5_client, hash, &hlen) < 0) {
    tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
        TLS_ALERT_INTERNAL_ERROR);
    conn->verify.md5_client = NULL;
    crypto_hash_finish(conn->verify.sha1_client, NULL, NULL);
    conn->verify.sha1_client = NULL;
    return -1;
  }
  conn->verify.md5_client = NULL;
  hlen = SHA1_MAC_LEN;
  if (conn->verify.sha1_client == NULL ||
      crypto_hash_finish(conn->verify.sha1_client, hash + MD5_MAC_LEN,
             &hlen) < 0) {
    conn->verify.sha1_client = NULL;
    tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
        TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }
  conn->verify.sha1_client = 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,
        "client finished", hash, hlen,
        verify_data + 1 + 3, TLS_VERIFY_DATA_LEN)) {
    wpa_printf(MSG_DEBUG, "TLSv1: Failed to generate verify_data");
    tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
        TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }
  wpa_hexdump_key(MSG_DEBUG, "TLSv1: verify_data (client)",
      verify_data + 1 + 3, TLS_VERIFY_DATA_LEN);

  /* 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; /* verify_data already in place */
  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");
    tls_alert(conn, TLS_ALERT_LEVEL_FATAL,
        TLS_ALERT_INTERNAL_ERROR);
    return -1;
  }

  *msgpos += rlen;

  return 0;
}


static u8 * tls_send_client_key_exchange(struct tlsv1_client *conn,
           size_t *out_len)
{
  u8 *msg, *end, *pos;
  size_t msglen;

  *out_len = 0;

  msglen = 2000;
  if (conn->certificate_requested)
    msglen += tls_client_cert_chain_der_len(conn);

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

  pos = msg;
  end = msg + msglen;

  if (conn->certificate_requested) {
    if (tls_write_client_certificate(conn, &pos, end) < 0) {
      os_free(msg);
      return NULL;
    }
  }

  if (tls_write_client_key_exchange(conn, &pos, end) < 0 ||
      (conn->certificate_requested && conn->cred && conn->cred->key &&
       tls_write_client_certificate_verify(conn, &pos, end) < 0) ||
      tls_write_client_change_cipher_spec(conn, &pos, end) < 0 ||
      tls_write_client_finished(conn, &pos, end) < 0) {
    os_free(msg);
    return NULL;
  }

  *out_len = pos - msg;

  conn->state = SERVER_CHANGE_CIPHER_SPEC;

  return msg;
}


static u8 * tls_send_change_cipher_spec(struct tlsv1_client *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_client_change_cipher_spec(conn, &pos, end) < 0 ||
      tls_write_client_finished(conn, &pos, end) < 0) {
    os_free(msg);
    return NULL;
  }

  *out_len = pos - msg;

  wpa_printf(MSG_DEBUG, "TLSv1: Session resumption completed "
       "successfully");
  if (!conn->session_resumed && conn->use_session_ticket)
    conn->session_resumed = 1;
  conn->state = ESTABLISHED;

  return msg;
}


u8 * tlsv1_client_handshake_write(struct tlsv1_client *conn, size_t *out_len,
          int no_appl_data)
{
  switch (conn->state) {
  case CLIENT_KEY_EXCHANGE:
    return tls_send_client_key_exchange(conn, out_len);
  case CHANGE_CIPHER_SPEC:
    return tls_send_change_cipher_spec(conn, out_len);
  case ACK_FINISHED:
    wpa_printf(MSG_DEBUG, "TLSv1: Handshake completed "
         "successfully");
    conn->state = ESTABLISHED;
    *out_len = 0;
    if (no_appl_data) {
      /* Need to return something to get final TLS ACK. */
      return os_malloc(1);
    }
    return NULL;
  default:
    wpa_printf(MSG_DEBUG, "TLSv1: Unexpected state %d while "
         "generating reply", conn->state);
    return NULL;
  }
}


u8 * tlsv1_client_send_alert(struct tlsv1_client *conn, u8 level,
           u8 description, size_t *out_len)
{
  u8 *alert, *pos, *length;

  wpa_printf(MSG_DEBUG, "TLSv1: 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: 2025-10-10 06:31