lib/auth_dhe.c

   1 /*
   2  * Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2007 Free Software Foundation
   3  *
   4  * Author: Nikos Mavrogiannopoulos
   5  *
   6  * This file is part of GNUTLS.
   7  *
   8  * The GNUTLS library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public License
  10  * as published by the Free Software Foundation; either version 2.1 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  21  * USA
  22  *
  23  */
  24
  25 /* This file contains everything for the Ephemeral Diffie Hellman (DHE)
  26  * key exchange. This is used in the handshake procedure of the certificate
  27  * authentication.
  28  */
  29
  30 #include "gnutls_int.h"
  31 #include "gnutls_auth_int.h"
  32 #include "gnutls_errors.h"
  33 #include "gnutls_dh.h"
  34 #include "gnutls_num.h"
  35 #include "gnutls_sig.h"
  36 #include <gnutls_datum.h>
  37 #include <auth_cert.h>
  38 #include <gnutls_x509.h>
  39 #include <gnutls_state.h>
  40 #include <auth_dh_common.h>
  41
  42 static int gen_dhe_server_kx (gnutls_session_t, opaque **);
  43 static int proc_dhe_server_kx (gnutls_session_t, opaque *, size_t);
  44 static int proc_dhe_client_kx (gnutls_session_t, opaque *, size_t);
  45
  46 const mod_auth_st dhe_rsa_auth_struct = {
  47   "DHE_RSA",
  48   _gnutls_gen_cert_server_certificate,
  49   _gnutls_gen_cert_client_certificate,
  50   gen_dhe_server_kx,
  51   _gnutls_gen_dh_common_client_kx,
  52   _gnutls_gen_cert_client_cert_vrfy,    /* gen client cert vrfy */
  53   _gnutls_gen_cert_server_cert_req,     /* server cert request */
  54
  55   _gnutls_proc_cert_server_certificate,
  56   _gnutls_proc_cert_client_certificate,
  57   proc_dhe_server_kx,
  58   proc_dhe_client_kx,
  59   _gnutls_proc_cert_client_cert_vrfy,   /* proc client cert vrfy */
  60   _gnutls_proc_cert_cert_req    /* proc server cert request */
  61 };
  62
  63 const mod_auth_st dhe_dss_auth_struct = {
  64   "DHE_DSS",
  65   _gnutls_gen_cert_server_certificate,
  66   _gnutls_gen_cert_client_certificate,
  67   gen_dhe_server_kx,
  68   _gnutls_gen_dh_common_client_kx,
  69   _gnutls_gen_cert_client_cert_vrfy,    /* gen client cert vrfy */
  70   _gnutls_gen_cert_server_cert_req,     /* server cert request */
  71
  72   _gnutls_proc_cert_server_certificate,
  73   _gnutls_proc_cert_client_certificate,
  74   proc_dhe_server_kx,
  75   proc_dhe_client_kx,
  76   _gnutls_proc_cert_client_cert_vrfy,   /* proc client cert vrfy */
  77   _gnutls_proc_cert_cert_req    /* proc server cert request */
  78 };
  79
  80
  81 static int
  82 gen_dhe_server_kx (gnutls_session_t session, opaque ** data)
  83 {
  84   mpi_t g, p;
  85   const mpi_t *mpis;
  86   int ret = 0, data_size;
  87   int bits;
  88   gnutls_cert *apr_cert_list;
  89   gnutls_privkey *apr_pkey;
  90   int apr_cert_list_length;
  91   gnutls_datum_t signature, ddata;
  92   gnutls_certificate_credentials_t cred;
  93   gnutls_dh_params_t dh_params;
  94
  95   cred = (gnutls_certificate_credentials_t)
  96     _gnutls_get_cred (session->key, GNUTLS_CRD_CERTIFICATE, NULL);
  97   if (cred == NULL)
  98     {
  99       gnutls_assert ();
 100       return GNUTLS_E_INSUFFICIENT_CREDENTIALS;
 101     }
 102
 103   bits = _gnutls_dh_get_allowed_prime_bits (session);
 104
 105   /* find the appropriate certificate */
 106   if ((ret =
 107        _gnutls_get_selected_cert (session, &apr_cert_list,
 108                                   &apr_cert_list_length, &apr_pkey)) < 0)
 109     {
 110       gnutls_assert ();
 111       return ret;
 112     }
 113
 114   dh_params =
 115     _gnutls_get_dh_params (cred->dh_params, cred->params_func, session);
 116   mpis = _gnutls_dh_params_to_mpi (dh_params);
 117   if (mpis == NULL)
 118     {
 119       gnutls_assert ();
 120       return GNUTLS_E_NO_TEMPORARY_DH_PARAMS;
 121     }
 122
 123   p = mpis[0];
 124   g = mpis[1];
 125
 126   if ((ret = _gnutls_auth_info_set (session, GNUTLS_CRD_CERTIFICATE,
 127                                     sizeof (cert_auth_info_st), 0)) < 0)
 128     {
 129       gnutls_assert ();
 130       return ret;
 131     }
 132
 133   _gnutls_dh_set_group (session, g, p);
 134
 135   ret = _gnutls_dh_common_print_server_kx (session, g, p, data, 0);
 136   if (ret < 0)
 137     {
 138       gnutls_assert ();
 139       return ret;
 140     }
 141   data_size = ret;
 142
 143   /* Generate the signature. */
 144
 145   ddata.data = *data;
 146   ddata.size = data_size;
 147
 148   if (apr_cert_list_length > 0)
 149     {
 150       if ((ret =
 151            _gnutls_tls_sign_params (session, &apr_cert_list[0],
 152                                     apr_pkey, &ddata, &signature)) < 0)
 153         {
 154           gnutls_assert ();
 155           gnutls_free (*data);
 156           return ret;
 157         }
 158     }
 159   else
 160     {
 161       gnutls_assert ();
 162       return data_size;         /* do not put a signature - ILLEGAL! */
 163     }
 164
 165   *data = gnutls_realloc_fast (*data, data_size + signature.size + 2);
 166   if (*data == NULL)
 167     {
 168       _gnutls_free_datum (&signature);
 169       gnutls_assert ();
 170       return GNUTLS_E_MEMORY_ERROR;
 171     }
 172
 173   _gnutls_write_datum16 (&(*data)[data_size], signature);
 174   data_size += signature.size + 2;
 175
 176   _gnutls_free_datum (&signature);
 177
 178   return data_size;
 179 }
 180
 181 static int
 182 proc_dhe_server_kx (gnutls_session_t session, opaque * data,
 183                     size_t _data_size)
 184 {
 185   int sigsize;
 186   gnutls_datum_t vparams, signature;
 187   int ret;
 188   cert_auth_info_t info = _gnutls_get_auth_info (session);
 189   ssize_t data_size = _data_size;
 190   gnutls_cert peer_cert;
 191
 192   if (info == NULL || info->ncerts == 0)
 193     {
 194       gnutls_assert ();
 195       /* we need this in order to get peer's certificate */
 196       return GNUTLS_E_INTERNAL_ERROR;
 197     }
 198
 199   ret = _gnutls_proc_dh_common_server_kx (session, data, _data_size, 0);
 200   if (ret < 0)
 201     {
 202       gnutls_assert ();
 203       return ret;
 204     }
 205
 206   /* VERIFY SIGNATURE */
 207
 208   vparams.size = ret;
 209   vparams.data = data;
 210
 211   DECR_LEN (data_size, 2);
 212   sigsize = _gnutls_read_uint16 (&data[vparams.size]);
 213
 214   DECR_LEN (data_size, sigsize);
 215   signature.data = &data[vparams.size + 2];
 216   signature.size = sigsize;
 217
 218   if ((ret =
 219        _gnutls_get_auth_info_gcert (&peer_cert,
 220                                   session->security_parameters.cert_type,
 221                                   info,
 222                                   CERT_NO_COPY)) < 0)
 223     {
 224       gnutls_assert ();
 225       return ret;
 226     }
 227
 228   ret = _gnutls_verify_sig_params (session, &peer_cert, &vparams, &signature);
 229
 230   _gnutls_gcert_deinit (&peer_cert);
 231   if (ret < 0)
 232     {
 233       gnutls_assert ();
 234       return ret;
 235     }
 236
 237   return ret;
 238 }
 239
 240
 241
 242 static int
 243 proc_dhe_client_kx (gnutls_session_t session, opaque * data,
 244                     size_t _data_size)
 245 {
 246   gnutls_certificate_credentials_t cred;
 247   int ret;
 248   mpi_t p, g;
 249   const mpi_t *mpis;
 250   gnutls_dh_params_t dh_params;
 251
 252   cred = (gnutls_certificate_credentials_t)
 253     _gnutls_get_cred (session->key, GNUTLS_CRD_CERTIFICATE, NULL);
 254   if (cred == NULL)
 255     {
 256       gnutls_assert ();
 257       return GNUTLS_E_INSUFFICIENT_CREDENTIALS;
 258     }
 259
 260   dh_params =
 261     _gnutls_get_dh_params (cred->dh_params, cred->params_func, session);
 262   mpis = _gnutls_dh_params_to_mpi (dh_params);
 263   if (mpis == NULL)
 264     {
 265       gnutls_assert ();
 266       return GNUTLS_E_NO_TEMPORARY_DH_PARAMS;
 267     }
 268
 269   p = mpis[0];
 270   g = mpis[1];
 271
 272   ret = _gnutls_proc_dh_common_client_kx (session, data, _data_size, g, p);
 273
 274   return ret;
 275
 276 }