lib/ext_cert_type.c

   1 /*
   2  * Copyright (C) 2002, 2003, 2004, 2005 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 code the Certificate Type TLS extension.
  26  * This extension is currently gnutls specific.
  27  */
  28
  29 #include "gnutls_int.h"
  30 #include "gnutls_errors.h"
  31 #include "gnutls_num.h"
  32 #include "ext_cert_type.h"
  33 #include <gnutls_state.h>
  34 #include <gnutls_num.h>
  35
  36 inline static int _gnutls_num2cert_type (int num);
  37 inline static int _gnutls_cert_type2num (int record_size);
  38
  39 /*
  40  * In case of a server: if a CERT_TYPE extension type is received then it stores
  41  * into the session security parameters the new value. The server may use gnutls_session_certificate_type_get(),
  42  * to access it.
  43  *
  44  * In case of a client: If a cert_types have been specified then we send the extension.
  45  *
  46  */
  47
  48 int
  49 _gnutls_cert_type_recv_params (gnutls_session_t session,
  50                                const opaque * data, size_t _data_size)
  51 {
  52   int new_type = -1, ret, i;
  53   ssize_t data_size = _data_size;
  54
  55   if (session->security_parameters.entity == GNUTLS_CLIENT)
  56     {
  57       if (data_size > 0)
  58         {
  59           if (data_size != 1)
  60             {
  61               gnutls_assert ();
  62               return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
  63             }
  64
  65           new_type = _gnutls_num2cert_type (data[0]);
  66
  67           if (new_type < 0)
  68             {
  69               gnutls_assert ();
  70               return new_type;
  71             }
  72
  73           /* Check if we support this cert_type */
  74           if ((ret =
  75                _gnutls_session_cert_type_supported (session, new_type)) < 0)
  76             {
  77               gnutls_assert ();
  78               return ret;
  79             }
  80
  81           _gnutls_session_cert_type_set (session, new_type);
  82         }
  83     }
  84   else
  85     {                           /* SERVER SIDE - we must check if the sent cert type is the right one
  86                                  */
  87       if (data_size > 1)
  88         {
  89           uint8_t len;
  90
  91           len = data[0];
  92           DECR_LEN (data_size, len);
  93
  94           for (i = 0; i < len; i++)
  95             {
  96               new_type = _gnutls_num2cert_type (data[i + 1]);
  97
  98               if (new_type < 0)
  99                 continue;
 100
 101               /* Check if we support this cert_type */
 102               if ((ret =
 103                    _gnutls_session_cert_type_supported (session,
 104                                                         new_type)) < 0)
 105                 {
 106                   gnutls_assert ();
 107                   continue;
 108                 }
 109               else
 110                 break;
 111               /* new_type is ok */
 112             }
 113
 114           if (new_type < 0)
 115             {
 116               gnutls_assert ();
 117               return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
 118             }
 119
 120           if ((ret =
 121                _gnutls_session_cert_type_supported (session, new_type)) < 0)
 122             {
 123               gnutls_assert ();
 124               /* The peer has requested unsupported certificate
 125                * types. Instead of failing, procceed normally.
 126                * (the ciphersuite selection would fail, or a
 127                * non certificate ciphersuite will be selected).
 128                */
 129               return 0;
 130             }
 131
 132           _gnutls_session_cert_type_set (session, new_type);
 133         }
 134
 135
 136     }
 137
 138   return 0;
 139 }
 140
 141 /* returns data_size or a negative number on failure
 142  */
 143 int
 144 _gnutls_cert_type_send_params (gnutls_session_t session, opaque * data,
 145                                size_t data_size)
 146 {
 147   unsigned len, i;
 148
 149   /* this function sends the client extension data (dnsname) */
 150   if (session->security_parameters.entity == GNUTLS_CLIENT)
 151     {
 152
 153       if (session->internals.priorities.cert_type.algorithms > 0)
 154         {
 155
 156           len = session->internals.priorities.cert_type.algorithms;
 157
 158           if (len == 1 &&
 159               session->internals.priorities.cert_type.priority[0] ==
 160               GNUTLS_CRT_X509)
 161             {
 162               /* We don't use this extension if X.509 certificates
 163                * are used.
 164                */
 165               return 0;
 166             }
 167
 168           if (data_size < len + 1)
 169             {
 170               gnutls_assert ();
 171               return GNUTLS_E_SHORT_MEMORY_BUFFER;
 172             }
 173
 174           /* this is a vector!
 175            */
 176           data[0] = (uint8_t) len;
 177
 178           for (i = 0; i < len; i++)
 179             {
 180               data[i + 1] = _gnutls_cert_type2num (session->internals.
 181                                                    priorities.cert_type.
 182                                                    priority[i]);
 183             }
 184           return len + 1;
 185         }
 186
 187     }
 188   else
 189     {                           /* server side */
 190       if (session->security_parameters.cert_type != DEFAULT_CERT_TYPE)
 191         {
 192           len = 1;
 193           if (data_size < len)
 194             {
 195               gnutls_assert ();
 196               return GNUTLS_E_SHORT_MEMORY_BUFFER;
 197             }
 198
 199           data[0] =
 200             _gnutls_cert_type2num (session->security_parameters.cert_type);
 201           return len;
 202         }
 203
 204
 205     }
 206
 207   return 0;
 208 }
 209
 210 /* Maps numbers to record sizes according to the
 211  * extensions draft.
 212  */
 213 inline static int
 214 _gnutls_num2cert_type (int num)
 215 {
 216   switch (num)
 217     {
 218     case 0:
 219       return GNUTLS_CRT_X509;
 220     case 1:
 221       return GNUTLS_CRT_OPENPGP;
 222     default:
 223       return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
 224     }
 225 }
 226
 227 /* Maps record size to numbers according to the
 228  * extensions draft.
 229  */
 230 inline static int
 231 _gnutls_cert_type2num (int cert_type)
 232 {
 233   switch (cert_type)
 234     {
 235     case GNUTLS_CRT_X509:
 236       return 0;
 237     case GNUTLS_CRT_OPENPGP:
 238       return 1;
 239     default:
 240       return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
 241     }
 242
 243 }