lib/ext_cert_type.c

   1 /*
   2  * Copyright (C) 2002, 2003, 2004, 2005, 2010 Free Software Foundation,
   3  * Inc.
   4  *
   5  * Author: Nikos Mavrogiannopoulos
   6  *
   7  * This file is part of GNUTLS.
   8  *
   9  * The GNUTLS library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public License
  11  * as published by the Free Software Foundation; either version 2.1 of
  12  * the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  22  * USA
  23  *
  24  */
  25
  26 /* This file contains the code the Certificate Type TLS extension.
  27  * This extension is currently gnutls specific.
  28  */
  29
  30 #include "gnutls_int.h"
  31 #include "gnutls_errors.h"
  32 #include "gnutls_num.h"
  33 #include "ext_cert_type.h"
  34 #include <gnutls_state.h>
  35 #include <gnutls_num.h>
  36
  37 inline static int _gnutls_num2cert_type (int num);
  38 inline static int _gnutls_cert_type2num (int record_size);
  39
  40 /*
  41  * In case of a server: if a CERT_TYPE extension type is received then it stores
  42  * into the session security parameters the new value. The server may use gnutls_session_certificate_type_get(),
  43  * to access it.
  44  *
  45  * In case of a client: If a cert_types have been specified then we send the extension.
  46  *
  47  */
  48
  49 int
  50 _gnutls_cert_type_recv_params (gnutls_session_t session,
  51                                const opaque * data, size_t _data_size)
  52 {
  53   int new_type = -1, ret, i;
  54   ssize_t data_size = _data_size;
  55
  56   if (session->security_parameters.entity == GNUTLS_CLIENT)
  57     {
  58       if (data_size > 0)
  59         {
  60           if (data_size != 1)
  61             {
  62               gnutls_assert ();
  63               return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
  64             }
  65
  66           new_type = _gnutls_num2cert_type (data[0]);
  67
  68           if (new_type < 0)
  69             {
  70               gnutls_assert ();
  71               return new_type;
  72             }
  73
  74           /* Check if we support this cert_type */
  75           if ((ret =
  76                _gnutls_session_cert_type_supported (session, new_type)) < 0)
  77             {
  78               gnutls_assert ();
  79               return ret;
  80             }
  81
  82           _gnutls_session_cert_type_set (session, new_type);
  83         }
  84     }
  85   else
  86     {                           /* SERVER SIDE - we must check if the sent cert type is the right one
  87                                  */
  88       if (data_size > 1)
  89         {
  90           uint8_t len;
  91
  92           DECR_LEN (data_size, 1);
  93           len = data[0];
  94           DECR_LEN (data_size, len);
  95
  96           for (i = 0; i < len; i++)
  97             {
  98               new_type = _gnutls_num2cert_type (data[i + 1]);
  99
 100               if (new_type < 0)
 101                 continue;
 102
 103               /* Check if we support this cert_type */
 104               if ((ret =
 105                    _gnutls_session_cert_type_supported (session,
 106                                                         new_type)) < 0)
 107                 {
 108                   gnutls_assert ();
 109                   continue;
 110                 }
 111               else
 112                 break;
 113               /* new_type is ok */
 114             }
 115
 116           if (new_type < 0)
 117             {
 118               gnutls_assert ();
 119               return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
 120             }
 121
 122           if ((ret =
 123                _gnutls_session_cert_type_supported (session, new_type)) < 0)
 124             {
 125               gnutls_assert ();
 126               /* The peer has requested unsupported certificate
 127                * types. Instead of failing, procceed normally.
 128                * (the ciphersuite selection would fail, or a
 129                * non certificate ciphersuite will be selected).
 130                */
 131               return 0;
 132             }
 133
 134           _gnutls_session_cert_type_set (session, new_type);
 135         }
 136
 137
 138     }
 139
 140   return 0;
 141 }
 142
 143 /* returns data_size or a negative number on failure
 144  */
 145 int
 146 _gnutls_cert_type_send_params (gnutls_session_t session, opaque * data,
 147                                size_t data_size)
 148 {
 149   unsigned len, i;
 150
 151   /* this function sends the client extension data (dnsname) */
 152   if (session->security_parameters.entity == GNUTLS_CLIENT)
 153     {
 154
 155       if (session->internals.priorities.cert_type.algorithms > 0)
 156         {
 157
 158           len = session->internals.priorities.cert_type.algorithms;
 159
 160           if (len == 1 &&
 161               session->internals.priorities.cert_type.priority[0] ==
 162               GNUTLS_CRT_X509)
 163             {
 164               /* We don't use this extension if X.509 certificates
 165                * are used.
 166                */
 167               return 0;
 168             }
 169
 170           if (data_size < len + 1)
 171             {
 172               gnutls_assert ();
 173               return GNUTLS_E_SHORT_MEMORY_BUFFER;
 174             }
 175
 176           /* this is a vector!
 177            */
 178           data[0] = (uint8_t) len;
 179
 180           for (i = 0; i < len; i++)
 181             {
 182               data[i + 1] =
 183                 _gnutls_cert_type2num (session->internals.
 184                                        priorities.cert_type.priority[i]);
 185             }
 186           return len + 1;
 187         }
 188
 189     }
 190   else
 191     {                           /* server side */
 192       if (session->security_parameters.cert_type != DEFAULT_CERT_TYPE)
 193         {
 194           len = 1;
 195           if (data_size < len)
 196             {
 197               gnutls_assert ();
 198               return GNUTLS_E_SHORT_MEMORY_BUFFER;
 199             }
 200
 201           data[0] =
 202             _gnutls_cert_type2num (session->security_parameters.cert_type);
 203           return len;
 204         }
 205
 206
 207     }
 208
 209   return 0;
 210 }
 211
 212 /* Maps numbers to record sizes according to the
 213  * extensions draft.
 214  */
 215 inline static int
 216 _gnutls_num2cert_type (int num)
 217 {
 218   switch (num)
 219     {
 220     case 0:
 221       return GNUTLS_CRT_X509;
 222     case 1:
 223       return GNUTLS_CRT_OPENPGP;
 224     default:
 225       return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
 226     }
 227 }
 228
 229 /* Maps record size to numbers according to the
 230  * extensions draft.
 231  */
 232 inline static int
 233 _gnutls_cert_type2num (int cert_type)
 234 {
 235   switch (cert_type)
 236     {
 237     case GNUTLS_CRT_X509:
 238       return 0;
 239     case GNUTLS_CRT_OPENPGP:
 240       return 1;
 241     default:
 242       return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
 243     }
 244
 245 }