src/libcharon/encoding/payloads/eap_payload.c

   1 /*
   2  * Copyright (C) 2005-2010 Martin Willi
   3  * Copyright (C) 2005 Jan Hutter
   4  * Hochschule fuer Technik Rapperswil
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the
   8  * Free Software Foundation; either version 2 of the License, or (at your
   9  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  13  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * for more details.
  15  */
  16
  17 #include <stddef.h>
  18
  19 #include "eap_payload.h"
  20
  21 #include <daemon.h>
  22 #include <eap/eap.h>
  23
  24 typedef struct private_eap_payload_t private_eap_payload_t;
  25
  26 /**
  27  * Private data of an eap_payload_t object.
  28  *
  29  */
  30 struct private_eap_payload_t {
  31         /**
  32          * Public eap_payload_t interface.
  33          */
  34         eap_payload_t public;
  35
  36         /**
  37          * Next payload type.
  38          */
  39         u_int8_t  next_payload;
  40
  41         /**
  42          * Critical flag.
  43          */
  44         bool critical;
  45
  46         /**
  47          * Reserved bits
  48          */
  49         bool reserved[7];
  50
  51         /**
  52          * Length of this payload.
  53          */
  54         u_int16_t payload_length;
  55
  56         /**
  57          * EAP message data, if available
  58          */
  59         chunk_t data;
  60 };
  61
  62 /**
  63  * Encoding rules to parse or generate a EAP payload.
  64  *
  65  * The defined offsets are the positions in a object of type
  66  * private_eap_payload_t.
  67  *
  68  */
  69 static encoding_rule_t encodings[] = {
  70         /* 1 Byte next payload type, stored in the field next_payload */
  71         { U_INT_8,                      offsetof(private_eap_payload_t, next_payload)   },
  72         /* the critical bit */
  73         { FLAG,                         offsetof(private_eap_payload_t, critical)               },
  74         /* 7 Bit reserved bits, nowhere stored */
  75         { RESERVED_BIT,         offsetof(private_eap_payload_t, reserved[0])    },
  76         { RESERVED_BIT,         offsetof(private_eap_payload_t, reserved[1])    },
  77         { RESERVED_BIT,         offsetof(private_eap_payload_t, reserved[2])    },
  78         { RESERVED_BIT,         offsetof(private_eap_payload_t, reserved[3])    },
  79         { RESERVED_BIT,         offsetof(private_eap_payload_t, reserved[4])    },
  80         { RESERVED_BIT,         offsetof(private_eap_payload_t, reserved[5])    },
  81         { RESERVED_BIT,         offsetof(private_eap_payload_t, reserved[6])    },
  82         /* Length of the whole payload*/
  83         { PAYLOAD_LENGTH,       offsetof(private_eap_payload_t, payload_length) },
  84         /* chunt to data, starting at "code" */
  85         { CHUNK_DATA,           offsetof(private_eap_payload_t, data)                   },
  86 };
  87
  88 /*
  89                             1                   2                   3
  90         0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  91        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  92        ! Next Payload  !C!  RESERVED   !         Payload Length        !
  93        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  94        !     Code      ! Identifier    !           Length              !
  95        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  96        !     Type      ! Type_Data...
  97        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
  98 */
  99
 100 METHOD(payload_t, verify, status_t,
 101         private_eap_payload_t *this)
 102 {
 103         u_int16_t length;
 104         u_int8_t code;
 105
 106         if (this->data.len < 4)
 107         {
 108                 DBG1(DBG_ENC, "EAP payloads EAP message too short (%d)", this->data.len);
 109                 return FAILED;
 110         }
 111         length = untoh16(this->data.ptr + 2);
 112         if (this->data.len != length)
 113         {
 114                 DBG1(DBG_ENC, "EAP payload length (%d) does not match contained "
 115                          "message length (%d)", this->data.len, length);
 116                 return FAILED;
 117         }
 118         code = this->data.ptr[0];
 119         switch (code)
 120         {
 121                 case EAP_REQUEST:
 122                 case EAP_RESPONSE:
 123                 {
 124                         if (this->data.len < 4)
 125                         {
 126                                 DBG1(DBG_ENC, "EAP Request/Response does not have any data");
 127                                 return FAILED;
 128                         }
 129                         break;
 130                 }
 131                 case EAP_SUCCESS:
 132                 case EAP_FAILURE:
 133                 {
 134                         if (this->data.len != 4)
 135                         {
 136                                 DBG1(DBG_ENC, "EAP Success/Failure has data");
 137                                 return FAILED;
 138                         }
 139                         break;
 140                 }
 141                 default:
 142                         return FAILED;
 143         }
 144         return SUCCESS;
 145 }
 146
 147 METHOD(payload_t, get_encoding_rules, int,
 148         private_eap_payload_t *this, encoding_rule_t **rules)
 149 {
 150         *rules = encodings;
 151         return countof(encodings);
 152 }
 153
 154 METHOD(payload_t, get_header_length, int,
 155         private_eap_payload_t *this)
 156 {
 157         return 4;
 158 }
 159
 160 METHOD(payload_t, get_payload_type, payload_type_t,
 161         private_eap_payload_t *this)
 162 {
 163         return EXTENSIBLE_AUTHENTICATION;
 164 }
 165
 166 METHOD(payload_t, get_next_type, payload_type_t,
 167         private_eap_payload_t *this)
 168 {
 169         return (this->next_payload);
 170 }
 171
 172 METHOD(payload_t, set_next_type, void,
 173         private_eap_payload_t *this, payload_type_t type)
 174 {
 175         this->next_payload = type;
 176 }
 177
 178 METHOD(payload_t, get_length, size_t,
 179         private_eap_payload_t *this)
 180 {
 181         return this->payload_length;
 182 }
 183
 184 METHOD(eap_payload_t, get_data, chunk_t,
 185         private_eap_payload_t *this)
 186 {
 187         return this->data;
 188 }
 189
 190 METHOD(eap_payload_t, set_data, void,
 191         private_eap_payload_t *this, chunk_t data)
 192 {
 193         free(this->data.ptr);
 194         this->data = chunk_clone(data);
 195         this->payload_length = this->data.len + 4;
 196 }
 197
 198 METHOD(eap_payload_t, get_code, eap_code_t,
 199         private_eap_payload_t *this)
 200 {
 201         if (this->data.len > 0)
 202         {
 203                 return this->data.ptr[0];
 204         }
 205         /* should not happen, as it is verified */
 206         return 0;
 207 }
 208
 209 METHOD(eap_payload_t, get_identifier, u_int8_t,
 210         private_eap_payload_t *this)
 211 {
 212         if (this->data.len > 1)
 213         {
 214                 return this->data.ptr[1];
 215         }
 216         /* should not happen, as it is verified */
 217         return 0;
 218 }
 219
 220 METHOD(eap_payload_t, get_type, eap_type_t,
 221         private_eap_payload_t *this, u_int32_t *vendor)
 222 {
 223         eap_type_t type;
 224
 225         *vendor = 0;
 226         if (this->data.len > 4)
 227         {
 228                 type = this->data.ptr[4];
 229                 if (type != EAP_EXPANDED)
 230                 {
 231                         return type;
 232                 }
 233                 if (this->data.len >= 12)
 234                 {
 235                         *vendor = untoh32(this->data.ptr + 4) & 0x00FFFFFF;
 236                         return untoh32(this->data.ptr + 8);
 237                 }
 238         }
 239         return 0;
 240 }
 241
 242 METHOD2(payload_t, eap_payload_t, destroy, void,
 243         private_eap_payload_t *this)
 244 {
 245         chunk_free(&this->data);
 246         free(this);
 247 }
 248
 249 /*
 250  * Described in header
 251  */
 252 eap_payload_t *eap_payload_create()
 253 {
 254         private_eap_payload_t *this;
 255
 256         INIT(this,
 257                 .public = {
 258                         .payload_interface = {
 259                                 .verify = _verify,
 260                                 .get_encoding_rules = _get_encoding_rules,
 261                                 .get_header_length = _get_header_length,
 262                                 .get_length = _get_length,
 263                                 .get_next_type = _get_next_type,
 264                                 .set_next_type = _set_next_type,
 265                                 .get_type = _get_payload_type,
 266                                 .destroy = _destroy,
 267                         },
 268                         .get_data = _get_data,
 269                         .set_data = _set_data,
 270                         .get_code = _get_code,
 271                         .get_identifier = _get_identifier,
 272                         .get_type = _get_type,
 273                         .destroy = _destroy,
 274                 },
 275                 .next_payload = NO_PAYLOAD,
 276                 .payload_length = get_header_length(this),
 277         );
 278         return &this->public;
 279 }
 280
 281 /*
 282  * Described in header
 283  */
 284 eap_payload_t *eap_payload_create_data(chunk_t data)
 285 {
 286         eap_payload_t *this = eap_payload_create();
 287
 288         this->set_data(this, data);
 289         return this;
 290 }
 291
 292 /*
 293  * Described in header
 294  */
 295 eap_payload_t *eap_payload_create_data_own(chunk_t data)
 296 {
 297         eap_payload_t *this = eap_payload_create();
 298
 299         this->set_data(this, data);
 300         free(data.ptr);
 301         return this;
 302 }
 303
 304 /*
 305  * Described in header
 306  */
 307 eap_payload_t *eap_payload_create_code(eap_code_t code, u_int8_t identifier)
 308 {
 309         chunk_t data;
 310
 311         data = chunk_from_chars(code, identifier, 0, 0);
 312         htoun16(data.ptr + 2, data.len);
 313         return eap_payload_create_data(data);
 314 }
 315
 316 /*
 317  * Described in header
 318  */
 319 eap_payload_t *eap_payload_create_nak(u_int8_t identifier)
 320 {
 321         chunk_t data;
 322
 323         data = chunk_from_chars(EAP_RESPONSE, identifier, 0, 0, EAP_NAK);
 324         htoun16(data.ptr + 2, data.len);
 325         return eap_payload_create_data(data);
 326 }
 327