src/libimcv/pa_tnc/pa_tnc_msg.c

   1 /*
   2  * Copyright (C) 2011 Andreas Steffen
   3  *
   4  * HSR 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 "pa_tnc_msg.h"
  18
  19 #include <tls_writer.h>
  20 #include <tls_reader.h>
  21 #include <utils/linked_list.h>
  22 #include <tnc/pen/pen.h>
  23 #include <debug.h>
  24
  25
  26 typedef struct private_pa_tnc_msg_t private_pa_tnc_msg_t;
  27
  28 /**
  29  *   PA-TNC message header
  30  *
  31  *                        1                   2                   3
  32  *   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
  33  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  34  *  |    Version    |                    Reserved                   |
  35  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  36  *  |                       Message Identifier                      |
  37  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  38  */
  39
  40 #define PA_TNC_HEADER_SIZE      8
  41 #define PA_TNC_VERSION          0x01
  42 #define PA_TNC_RESERVED         0x000000
  43
  44 /**
  45  *  PA-TNC attribute
  46  *
  47  *                       1                   2                   3
  48  *  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
  49  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  50  *  |     Flags     |          PA-TNC Attribute Vendor ID           |
  51  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  52  *  |                     PA-TNC Attribute Type                     |
  53  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  54  *  |                    PA-TNC Attribute Length                    |
  55  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  56  *  |                 Attribute Value (Variable Length)             |
  57  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  58  */
  59
  60 #define PA_TNC_ATTR_FLAG_NONE                   0x00
  61 #define PA_TNC_ATTR_FLAG_NOSKIP                 (1<<7)
  62 #define PA_TNC_ATTR_HEADER_SIZE                 12
  63
  64 /**
  65  * Private data of a pa_tnc_msg_t object.
  66  *
  67  */
  68 struct private_pa_tnc_msg_t {
  69
  70         /**
  71          * Public pa_tnc_msg_t interface.
  72          */
  73         pa_tnc_msg_t public;
  74
  75         /**
  76          * List of PA-TNC attributes
  77          */
  78         linked_list_t *attributes;
  79
  80         /**
  81          * Message identifier
  82          */
  83         u_int32_t identifier;
  84
  85         /**
  86          * Encoded message
  87          */
  88         chunk_t encoding;
  89 };
  90
  91 METHOD(pa_tnc_msg_t, get_encoding, chunk_t,
  92         private_pa_tnc_msg_t *this)
  93 {
  94         return this->encoding;
  95 }
  96
  97 METHOD(pa_tnc_msg_t, add_attribute, void,
  98         private_pa_tnc_msg_t *this, pa_tnc_attr_t *attr)
  99 {
 100         this->attributes->insert_last(this->attributes, attr);
 101 }
 102
 103 METHOD(pa_tnc_msg_t, build, void,
 104         private_pa_tnc_msg_t *this)
 105 {
 106         tls_writer_t *writer;
 107         enumerator_t *enumerator;
 108         pa_tnc_attr_t *attr;
 109         pen_t vendor_id;
 110         u_int32_t type;
 111         u_int8_t flags;
 112         chunk_t value;
 113         rng_t *rng;
 114
 115         /* create a random message identifier */
 116         rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK);
 117         rng->get_bytes(rng, sizeof(this->identifier), (u_int8_t*)&this->identifier);
 118         rng->destroy(rng);
 119         DBG2(DBG_TNC, "creating PA-TNC message with ID 0x%08x", this->identifier);
 120
 121         /* build message header */
 122         writer = tls_writer_create(PA_TNC_HEADER_SIZE);
 123         writer->write_uint8 (writer, PA_TNC_VERSION);
 124         writer->write_uint24(writer, PA_TNC_RESERVED);
 125         writer->write_uint32(writer, this->identifier);
 126
 127         /* build and append encoding of PA-TNC attributes */
 128         enumerator = this->attributes->create_enumerator(this->attributes);
 129         while (enumerator->enumerate(enumerator, &attr))
 130         {
 131                 attr->build(attr);
 132                 vendor_id = attr->get_vendor_id(attr);
 133                 type = attr->get_type(attr);
 134                 value = attr->get_value(attr);
 135                 flags = attr->get_noskip_flag(attr) ? PA_TNC_ATTR_FLAG_NOSKIP :
 136                                                                                           PA_TNC_ATTR_FLAG_NONE;
 137                 DBG2(DBG_TNC, "creating PA-TNC attribute type 0x%06x(%N)/0x%08x",
 138                                            vendor_id, pen_names, vendor_id, type);
 139                 DBG3(DBG_TNC, "%B", &value);
 140
 141                 writer->write_uint8 (writer, flags);
 142                 writer->write_uint24(writer, vendor_id);
 143                 writer->write_uint32(writer, type);
 144                 writer->write_uint32(writer, PA_TNC_ATTR_HEADER_SIZE + value.len);
 145                 writer->write_data  (writer, value);
 146         }
 147         enumerator->destroy(enumerator);
 148
 149         free(this->encoding.ptr);
 150         this->encoding = chunk_clone(writer->get_buf(writer));
 151         writer->destroy(writer);
 152 }
 153
 154 METHOD(pa_tnc_msg_t, process, status_t,
 155         private_pa_tnc_msg_t *this)
 156 {
 157         u_int8_t version;
 158         u_int32_t reserved;
 159         tls_reader_t *reader;
 160         status_t status = FAILED;
 161
 162         reader = tls_reader_create(this->encoding);
 163
 164         /* process message header */
 165         if (reader->remaining(reader) < PA_TNC_HEADER_SIZE)
 166         {
 167                 DBG1(DBG_TNC, "%u bytes insufficient to parse PA-TNC message header",
 168                                            this->encoding.len);
 169                 goto end;
 170         }
 171         reader->read_uint8 (reader, &version);
 172         reader->read_uint24(reader, &reserved);
 173         reader->read_uint32(reader, &this->identifier);
 174
 175         if (version != PA_TNC_VERSION)
 176         {
 177                 DBG1(DBG_TNC, "PA-TNC version %u not supported", version);
 178                 goto end;
 179         }
 180         DBG2(DBG_TNC, "processing PA-TNC message with ID 0x%08x", this->identifier);
 181
 182         /* pre-process PA-TNC attributes */
 183         while (reader->remaining(reader) >= PA_TNC_ATTR_HEADER_SIZE)
 184         {
 185                 pen_t vendor_id;
 186                 u_int8_t flags;
 187                 u_int32_t type, length;
 188                 chunk_t value;
 189                 pa_tnc_attr_t *attr;
 190
 191                 reader->read_uint8 (reader, &flags);
 192                 reader->read_uint24(reader, &vendor_id);
 193                 reader->read_uint32(reader, &type);
 194                 reader->read_uint32(reader, &length);
 195                 DBG2(DBG_TNC, "processing PA-TNC attribute type 0x%06x(%N)/0x%08x",
 196                                            vendor_id, pen_names, vendor_id, type);
 197
 198                 if (length < PA_TNC_ATTR_HEADER_SIZE)
 199                 {
 200                         DBG1(DBG_TNC, "%u bytes too small for PA-TNC attribute length",
 201                                                    length);
 202                         goto end;
 203                 }
 204                 length -= PA_TNC_ATTR_HEADER_SIZE;
 205
 206                 if (!reader->read_data(reader, length , &value))
 207                 {
 208                         DBG1(DBG_TNC, "insufficient bytes for PA-TNC attribute value");
 209                         goto end;
 210                 }
 211                 DBG3(DBG_TNC, "%B", &value);
 212
 213                 attr = pa_tnc_attr_create_from_data(vendor_id, type, value);
 214                 if (!attr)
 215                 {
 216                         if (flags & PA_TNC_ATTR_FLAG_NOSKIP)
 217                         {
 218                                 DBG1(DBG_TNC, "unsupported PA-TNC attribute with NOSKIP flag");
 219                                 goto end;
 220                         }
 221                         else
 222                         {
 223                                 DBG1(DBG_TNC, "skipping unsupported PA-TNC attribute");
 224                         }
 225                 }
 226
 227                 if (attr->process(attr) != SUCCESS)
 228                 {
 229                         attr->destroy(attr);
 230                         goto end;
 231                 }
 232                 add_attribute(this, attr);
 233         }
 234
 235         if (reader->remaining(reader) == 0)
 236         {
 237                 status = SUCCESS;
 238         }
 239
 240 end:
 241         reader->destroy(reader);
 242         return status;
 243 }
 244
 245 METHOD(pa_tnc_msg_t, create_attribute_enumerator, enumerator_t*,
 246         private_pa_tnc_msg_t *this)
 247 {
 248         return this->attributes->create_enumerator(this->attributes);
 249 }
 250
 251 METHOD(pa_tnc_msg_t, destroy, void,
 252         private_pa_tnc_msg_t *this)
 253 {
 254         this->attributes->destroy_offset(this->attributes,
 255                                                                          offsetof(pa_tnc_attr_t, destroy));
 256         free(this->encoding.ptr);
 257         free(this);
 258 }
 259
 260
 261 /**
 262  * See header
 263  */
 264 pa_tnc_msg_t *pa_tnc_msg_create_from_data(chunk_t data)
 265 {
 266         private_pa_tnc_msg_t *this;
 267
 268         INIT(this,
 269                 .public = {
 270                         .get_encoding = _get_encoding,
 271                         .add_attribute = _add_attribute,
 272                         .build = _build,
 273                         .process = _process,
 274                         .create_attribute_enumerator = _create_attribute_enumerator,
 275                         .destroy = _destroy,
 276                 },
 277                 .encoding = chunk_clone(data),
 278                 .attributes = linked_list_create(),
 279         );
 280
 281         return &this->public;
 282 }
 283
 284 /**
 285  * See header
 286  */
 287 pa_tnc_msg_t *pa_tnc_msg_create(void)
 288 {
 289         return pa_tnc_msg_create_from_data(chunk_empty);
 290 }
 291
 292