lib/auth_rsa_export.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 the RSA key exchange part of the certificate
  26  * authentication.
  27  */
  28
  29 #include "gnutls_int.h"
  30 #include "gnutls_auth_int.h"
  31 #include "gnutls_errors.h"
  32 #include "gnutls_dh.h"
  33 #include "gnutls_num.h"
  34 #include "libtasn1.h"
  35 #include "gnutls_datum.h"
  36 #include "auth_cert.h"
  37 #include <gnutls_pk.h>
  38 #include <gnutls_algorithms.h>
  39 #include <gnutls_global.h>
  40 #include "debug.h"
  41 #include <gnutls_sig.h>
  42 #include <gnutls_x509.h>
  43 #include <gnutls_rsa_export.h>
  44 #include <gnutls_state.h>
  45
  46 int _gnutls_gen_rsa_client_kx (gnutls_session_t, opaque **);
  47 int _gnutls_proc_rsa_client_kx (gnutls_session_t, opaque *, size_t);
  48 static int gen_rsa_export_server_kx (gnutls_session_t, opaque **);
  49 static int proc_rsa_export_server_kx (gnutls_session_t, opaque *, size_t);
  50
  51 const mod_auth_st rsa_export_auth_struct = {
  52   "RSA EXPORT",
  53   _gnutls_gen_cert_server_certificate,
  54   _gnutls_gen_cert_client_certificate,
  55   gen_rsa_export_server_kx,
  56   _gnutls_gen_rsa_client_kx,
  57   _gnutls_gen_cert_client_cert_vrfy,    /* gen client cert vrfy */
  58   _gnutls_gen_cert_server_cert_req,     /* server cert request */
  59
  60   _gnutls_proc_cert_server_certificate,
  61   _gnutls_proc_cert_client_certificate,
  62   proc_rsa_export_server_kx,
  63   _gnutls_proc_rsa_client_kx,   /* proc client kx */
  64   _gnutls_proc_cert_client_cert_vrfy,   /* proc client cert vrfy */
  65   _gnutls_proc_cert_cert_req    /* proc server cert request */
  66 };
  67
  68 static int
  69 gen_rsa_export_server_kx (gnutls_session_t session, opaque ** data)
  70 {
  71   gnutls_rsa_params_t rsa_params;
  72   const mpi_t *rsa_mpis;
  73   size_t n_e, n_m;
  74   uint8_t *data_e, *data_m;
  75   int ret = 0, data_size;
  76   gnutls_cert *apr_cert_list;
  77   gnutls_privkey *apr_pkey;
  78   int apr_cert_list_length;
  79   gnutls_datum_t signature, ddata;
  80   cert_auth_info_t info;
  81   gnutls_certificate_credentials_t cred;
  82
  83   cred = (gnutls_certificate_credentials_t)
  84     _gnutls_get_cred (session->key, GNUTLS_CRD_CERTIFICATE, NULL);
  85   if (cred == NULL)
  86     {
  87       gnutls_assert ();
  88       return GNUTLS_E_INSUFFICIENT_CREDENTIALS;
  89     }
  90
  91   /* find the appropriate certificate */
  92   if ((ret =
  93        _gnutls_get_selected_cert (session, &apr_cert_list,
  94                                   &apr_cert_list_length, &apr_pkey)) < 0)
  95     {
  96       gnutls_assert ();
  97       return ret;
  98     }
  99
 100   /* abort sending this message if we have a certificate
 101    * of 512 bits or less.
 102    */
 103   if (apr_pkey && _gnutls_mpi_get_nbits (apr_pkey->params[0]) <= 512)
 104     {
 105       gnutls_assert ();
 106       return GNUTLS_E_INT_RET_0;
 107     }
 108
 109   rsa_params =
 110     _gnutls_certificate_get_rsa_params (cred->rsa_params, cred->params_func,
 111                                         session);
 112   rsa_mpis = _gnutls_rsa_params_to_mpi (rsa_params);
 113   if (rsa_mpis == NULL)
 114     {
 115       gnutls_assert ();
 116       return GNUTLS_E_NO_TEMPORARY_RSA_PARAMS;
 117     }
 118
 119   if ((ret = _gnutls_auth_info_set (session, GNUTLS_CRD_CERTIFICATE,
 120                                     sizeof (cert_auth_info_st), 0)) < 0)
 121     {
 122       gnutls_assert ();
 123       return ret;
 124     }
 125
 126   info = _gnutls_get_auth_info (session);
 127   _gnutls_rsa_export_set_pubkey (session, rsa_mpis[1], rsa_mpis[0]);
 128
 129   _gnutls_mpi_print (NULL, &n_m, rsa_mpis[0]);
 130   _gnutls_mpi_print (NULL, &n_e, rsa_mpis[1]);
 131
 132   (*data) = gnutls_malloc (n_e + n_m + 4);
 133   if (*data == NULL)
 134     {
 135       return GNUTLS_E_MEMORY_ERROR;
 136     }
 137
 138   data_m = &(*data)[0];
 139   _gnutls_mpi_print (&data_m[2], &n_m, rsa_mpis[0]);
 140
 141   _gnutls_write_uint16 (n_m, data_m);
 142
 143   data_e = &data_m[2 + n_m];
 144   _gnutls_mpi_print (&data_e[2], &n_e, rsa_mpis[1]);
 145
 146   _gnutls_write_uint16 (n_e, data_e);
 147
 148   data_size = n_m + n_e + 4;
 149
 150
 151   /* Generate the signature. */
 152
 153   ddata.data = *data;
 154   ddata.size = data_size;
 155
 156   if (apr_cert_list_length > 0)
 157     {
 158       if ((ret =
 159            _gnutls_tls_sign_params (session, &apr_cert_list[0],
 160                                     apr_pkey, &ddata, &signature)) < 0)
 161         {
 162           gnutls_assert ();
 163           gnutls_free (*data);
 164           *data = NULL;
 165           return ret;
 166         }
 167     }
 168   else
 169     {
 170       gnutls_assert ();
 171       return data_size;         /* do not put a signature - ILLEGAL! */
 172     }
 173
 174   *data = gnutls_realloc_fast (*data, data_size + signature.size + 2);
 175   if (*data == NULL)
 176     {
 177       _gnutls_free_datum (&signature);
 178       gnutls_assert ();
 179       return GNUTLS_E_MEMORY_ERROR;
 180     }
 181
 182   _gnutls_write_datum16 (&((*data)[data_size]), signature);
 183   data_size += signature.size + 2;
 184
 185   _gnutls_free_datum (&signature);
 186
 187   return data_size;
 188 }
 189
 190 /* if the peer's certificate is of 512 bits or less, returns non zero.
 191  */
 192 int
 193 _gnutls_peers_cert_less_512 (gnutls_session_t session)
 194 {
 195   gnutls_cert peer_cert;
 196   int ret;
 197   cert_auth_info_t info = _gnutls_get_auth_info (session);
 198
 199   if (info == NULL || info->ncerts == 0)
 200     {
 201       gnutls_assert ();
 202       /* we need this in order to get peer's certificate */
 203       return 0;
 204     }
 205
 206   if ((ret =
 207        _gnutls_get_auth_info_gcert (&peer_cert,
 208                                   session->security_parameters.cert_type,
 209                                   info, CERT_NO_COPY)) < 0)
 210     {
 211       gnutls_assert ();
 212       return 0;
 213     }
 214
 215   if (peer_cert.subject_pk_algorithm != GNUTLS_PK_RSA)
 216     {
 217       gnutls_assert ();
 218       _gnutls_gcert_deinit (&peer_cert);
 219       return 0;
 220     }
 221
 222   if (_gnutls_mpi_get_nbits (peer_cert.params[0]) <= 512)
 223     {
 224       _gnutls_gcert_deinit (&peer_cert);
 225       return 1;
 226     }
 227
 228   _gnutls_gcert_deinit (&peer_cert);
 229
 230   return 0;
 231 }
 232
 233 static int
 234 proc_rsa_export_server_kx (gnutls_session_t session,
 235                            opaque * data, size_t _data_size)
 236 {
 237   uint16_t n_m, n_e;
 238   size_t _n_m, _n_e;
 239   uint8_t *data_m;
 240   uint8_t *data_e;
 241   int i, sigsize;
 242   gnutls_datum_t vparams, signature;
 243   int ret;
 244   ssize_t data_size = _data_size;
 245   cert_auth_info_t info;
 246   gnutls_cert peer_cert;
 247
 248   info = _gnutls_get_auth_info (session);
 249   if (info == NULL || info->ncerts == 0)
 250     {
 251       gnutls_assert ();
 252       /* we need this in order to get peer's certificate */
 253       return GNUTLS_E_INTERNAL_ERROR;
 254     }
 255
 256
 257   i = 0;
 258
 259   DECR_LEN (data_size, 2);
 260   n_m = _gnutls_read_uint16 (&data[i]);
 261   i += 2;
 262
 263   DECR_LEN (data_size, n_m);
 264   data_m = &data[i];
 265   i += n_m;
 266
 267   DECR_LEN (data_size, 2);
 268   n_e = _gnutls_read_uint16 (&data[i]);
 269   i += 2;
 270
 271   DECR_LEN (data_size, n_e);
 272   data_e = &data[i];
 273   i += n_e;
 274
 275   _n_e = n_e;
 276   _n_m = n_m;
 277
 278   if (_gnutls_mpi_scan_nz (&session->key->rsa[0], data_m, &_n_m) != 0)
 279     {
 280       gnutls_assert ();
 281       return GNUTLS_E_MPI_SCAN_FAILED;
 282     }
 283
 284   if (_gnutls_mpi_scan_nz (&session->key->rsa[1], data_e, &_n_e) != 0)
 285     {
 286       gnutls_assert ();
 287       return GNUTLS_E_MPI_SCAN_FAILED;
 288     }
 289
 290   _gnutls_rsa_export_set_pubkey (session, session->key->rsa[1],
 291                                  session->key->rsa[0]);
 292
 293   /* VERIFY SIGNATURE */
 294
 295   vparams.size = n_m + n_e + 4;
 296   vparams.data = data;
 297
 298   DECR_LEN (data_size, 2);
 299   sigsize = _gnutls_read_uint16 (&data[vparams.size]);
 300
 301   DECR_LEN (data_size, sigsize);
 302   signature.data = &data[vparams.size + 2];
 303   signature.size = sigsize;
 304
 305   if ((ret =
 306        _gnutls_get_auth_info_gcert (&peer_cert,
 307                                   session->security_parameters.cert_type,
 308                                   info, CERT_NO_COPY)) < 0)
 309     {
 310       gnutls_assert ();
 311       return ret;
 312     }
 313
 314   ret = _gnutls_verify_sig_params (session, &peer_cert, &vparams, &signature);
 315
 316   _gnutls_gcert_deinit (&peer_cert);
 317   if (ret < 0)
 318     {
 319       gnutls_assert ();
 320     }
 321
 322   return ret;
 323 }