src/libimcv/plugins/imc_scanner/imc_scanner.c

   1 /*
   2  * Copyright (C) 2011 Andreas Steffen, HSR Hochschule fuer Technik Rapperswil
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License as published by the
   6  * Free Software Foundation; either version 2 of the License, or (at your
   7  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  11  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * for more details.
  13  */
  14
  15 #include "imc_scanner_state.h"
  16
  17 #include <imc/imc_agent.h>
  18 #include <pa_tnc/pa_tnc_msg.h>
  19 #include <ietf/ietf_attr.h>
  20 #include <ietf/ietf_attr_pa_tnc_error.h>
  21 #include <ietf/ietf_attr_port_filter.h>
  22
  23 #include <tncif_names.h>
  24 #include <tncif_pa_subtypes.h>
  25
  26 #include <pen/pen.h>
  27 #include <utils/lexparser.h>
  28 #include <debug.h>
  29
  30 #include <stdio.h>
  31
  32 /* IMC definitions */
  33
  34 static const char imc_name[] = "Scanner";
  35
  36 #define IMC_VENDOR_ID   PEN_ITA
  37 #define IMC_SUBTYPE             PA_SUBTYPE_ITA_SCANNER
  38
  39 static imc_agent_t *imc_scanner;
  40
  41 /**
  42  * see section 3.7.1 of TCG TNC IF-IMC Specification 1.2
  43  */
  44 TNC_Result TNC_IMC_Initialize(TNC_IMCID imc_id,
  45                                                           TNC_Version min_version,
  46                                                           TNC_Version max_version,
  47                                                           TNC_Version *actual_version)
  48 {
  49         if (imc_scanner)
  50         {
  51                 DBG1(DBG_IMC, "IMC \"%s\" has already been initialized", imc_name);
  52                 return TNC_RESULT_ALREADY_INITIALIZED;
  53         }
  54         imc_scanner = imc_agent_create(imc_name, IMC_VENDOR_ID, IMC_SUBTYPE,
  55                                                                 imc_id, actual_version);
  56         if (!imc_scanner)
  57         {
  58                 return TNC_RESULT_FATAL;
  59         }
  60         if (min_version > TNC_IFIMC_VERSION_1 || max_version < TNC_IFIMC_VERSION_1)
  61         {
  62                 DBG1(DBG_IMC, "no common IF-IMC version");
  63                 return TNC_RESULT_NO_COMMON_VERSION;
  64         }
  65         return TNC_RESULT_SUCCESS;
  66 }
  67
  68 /**
  69  * see section 3.7.2 of TCG TNC IF-IMC Specification 1.2
  70  */
  71 TNC_Result TNC_IMC_NotifyConnectionChange(TNC_IMCID imc_id,
  72                                                                                   TNC_ConnectionID connection_id,
  73                                                                                   TNC_ConnectionState new_state)
  74 {
  75         imc_state_t *state;
  76
  77         if (!imc_scanner)
  78         {
  79                 DBG1(DBG_IMC, "IMC \"%s\" has not been initialized", imc_name);
  80                 return TNC_RESULT_NOT_INITIALIZED;
  81         }
  82         switch (new_state)
  83         {
  84                 case TNC_CONNECTION_STATE_CREATE:
  85                         state = imc_scanner_state_create(connection_id);
  86                         return imc_scanner->create_state(imc_scanner, state);
  87                 case TNC_CONNECTION_STATE_DELETE:
  88                         return imc_scanner->delete_state(imc_scanner, connection_id);
  89                 default:
  90                         return imc_scanner->change_state(imc_scanner, connection_id,
  91                                                                                          new_state, NULL);
  92         }
  93 }
  94
  95 /**
  96  * Determine all TCP and UDP server sockets listening on physical interfaces
  97  */
  98 static bool do_netstat(ietf_attr_port_filter_t *attr)
  99 {
 100         FILE *file;
 101         char buf[BUF_LEN];
 102         chunk_t line, token;
 103         int n = 0;
 104         bool success = FALSE;
 105         const char loopback_v4[] = "127.0.0.1";
 106         const char loopback_v6[] = "::1";
 107
 108         /* Open a pipe stream for reading the output of the netstat commmand */
 109         file = popen("/bin/netstat -n -l -p -4 -6 --inet", "r");
 110         if (!file)
 111         {
 112                 DBG1(DBG_IMC, "Failed to run netstat command");
 113                 return FALSE;
 114         }
 115
 116         /* Read the output a line at a time */
 117         while (fgets(buf, BUF_LEN-1, file))
 118         {
 119                 u_char *pos;
 120                 u_int8_t new_protocol, protocol;
 121                 u_int16_t new_port, port;
 122                 int i;
 123                 enumerator_t *enumerator;
 124                 bool allowed, found = FALSE;
 125
 126                 DBG2(DBG_IMC, "%.*s", strlen(buf)-1, buf);
 127
 128                 if (n++ < 2)
 129                 {
 130                         /* skip the first two header lines */
 131                         continue;
 132                 }
 133                 line = chunk_create(buf, strlen(buf));
 134
 135                 /* Extract the IP protocol type */
 136                 if (!extract_token(&token, ' ', &line))
 137                 {
 138                         DBG1(DBG_IMC, "Protocol field in netstat output not found");
 139                         goto end;
 140                 }
 141                 if (match("tcp", &token) || match("tcp6", &token))
 142                 {
 143                         new_protocol = IPPROTO_TCP;
 144                 }
 145                 else if (match("udp", &token) || match("udp6", &token))
 146                 {
 147                         new_protocol = IPPROTO_UDP;
 148                 }
 149                 else
 150                 {
 151                         DBG1(DBG_IMC, "Skipped unknown IP protocol in netstat output");
 152                         continue;
 153                 }
 154
 155                 /* Skip the Recv-Q and Send-Q fields */
 156                 for (i = 0; i < 3; i++)
 157                 {
 158                         if (!eat_whitespace(&line) || !extract_token(&token, ' ', &line))
 159                         {
 160                                 token = chunk_empty;
 161                                 break;
 162                         }
 163                 }
 164                 if (token.len == 0)
 165                 {
 166                         DBG1(DBG_IMC, "Local Address field in netstat output not found");
 167                         goto end;
 168                 }
 169
 170                 /* Find the local port appended to the local address */
 171                 pos = token.ptr + token.len;
 172                 while (*--pos != ':' && --token.len);
 173                 if (*pos != ':')
 174                 {
 175                         DBG1(DBG_IMC, "Local port field in netstat output not found");
 176                         goto end;
 177                 }
 178                 token.len--;
 179
 180                 /* ignore ports of IPv4 and IPv6 loopback interfaces */
 181                 if ((token.len == strlen(loopback_v4) &&
 182                                 memeq(loopback_v4, token.ptr, token.len)) ||
 183                         (token.len == strlen(loopback_v6) &&
 184                                 memeq(loopback_v6, token.ptr, token.len)))
 185                 {
 186                         continue;
 187                 }
 188
 189                 /* convert the port string to an integer */
 190                 new_port = atoi(pos+1);
 191
 192                 /* check if the there is already a port entry */
 193                 enumerator = attr->create_port_enumerator(attr);
 194                 while (enumerator->enumerate(enumerator, &allowed, &protocol, &port))
 195                 {
 196                         if (new_port == port && new_protocol == protocol)
 197                         {
 198                                 found = TRUE;
 199                         }
 200                 }
 201                 enumerator->destroy(enumerator);
 202
 203                 /* Skip the duplicate port entry */
 204                 if (found)
 205                 {
 206                         continue;
 207                 }
 208
 209                 /* Add new port entry */
 210                 attr->add_port(attr, FALSE, new_protocol, new_port);
 211         }
 212
 213         /* Successfully completed the parsing of the netstat output */
 214         success = TRUE;
 215
 216 end:
 217         /* Close the pipe stream */
 218         pclose(file);
 219         return success;
 220 }
 221
 222 static TNC_Result send_message(TNC_ConnectionID connection_id)
 223 {
 224         pa_tnc_msg_t *msg;
 225         pa_tnc_attr_t *attr;
 226         ietf_attr_port_filter_t *attr_port_filter;
 227         TNC_Result result;
 228
 229         attr = ietf_attr_port_filter_create();
 230         attr->set_noskip_flag(attr, TRUE);
 231         attr_port_filter = (ietf_attr_port_filter_t*)attr;
 232         if (!do_netstat(attr_port_filter))
 233         {
 234                 attr->destroy(attr);
 235                 return TNC_RESULT_FATAL;
 236         }
 237         msg = pa_tnc_msg_create();
 238         msg->add_attribute(msg, attr);
 239         msg->build(msg);
 240         result = imc_scanner->send_message(imc_scanner, connection_id,
 241                                                                            msg->get_encoding(msg));
 242         msg->destroy(msg);
 243
 244         return result;
 245 }
 246
 247 /**
 248  * see section 3.7.3 of TCG TNC IF-IMC Specification 1.2
 249  */
 250 TNC_Result TNC_IMC_BeginHandshake(TNC_IMCID imc_id,
 251                                                                   TNC_ConnectionID connection_id)
 252 {
 253         if (!imc_scanner)
 254         {
 255                 DBG1(DBG_IMC, "IMC \"%s\" has not been initialized", imc_name);
 256                 return TNC_RESULT_NOT_INITIALIZED;
 257         }
 258         return send_message(connection_id);
 259 }
 260
 261 /**
 262  * see section 3.7.4 of TCG TNC IF-IMC Specification 1.2
 263  */
 264 TNC_Result TNC_IMC_ReceiveMessage(TNC_IMCID imc_id,
 265                                                                   TNC_ConnectionID connection_id,
 266                                                                   TNC_BufferReference msg,
 267                                                                   TNC_UInt32 msg_len,
 268                                                                   TNC_MessageType msg_type)
 269 {
 270         pa_tnc_msg_t *pa_tnc_msg;
 271         pa_tnc_attr_t *attr;
 272         enumerator_t *enumerator;
 273         TNC_Result result;
 274         bool fatal_error = FALSE;
 275
 276         if (!imc_scanner)
 277         {
 278                 DBG1(DBG_IMC, "IMC \"%s\" has not been initialized", imc_name);
 279                 return TNC_RESULT_NOT_INITIALIZED;
 280         }
 281
 282         /* parse received PA-TNC message and automatically handle any errors */
 283         result = imc_scanner->receive_message(imc_scanner, connection_id,
 284                                                                            chunk_create(msg, msg_len), msg_type,
 285                                                                            &pa_tnc_msg);
 286
 287         /* no parsed PA-TNC attributes available if an error occurred */
 288         if (!pa_tnc_msg)
 289         {
 290                 return result;
 291         }
 292
 293         /* analyze PA-TNC attributes */
 294         enumerator = pa_tnc_msg->create_attribute_enumerator(pa_tnc_msg);
 295         while (enumerator->enumerate(enumerator, &attr))
 296         {
 297                 ietf_attr_pa_tnc_error_t *error_attr;
 298                 pa_tnc_error_code_t error_code;
 299                 chunk_t msg_info, attr_info;
 300                 u_int32_t offset;
 301
 302                 if (attr->get_vendor_id(attr) != PEN_IETF &&
 303                         attr->get_type(attr) != IETF_ATTR_PA_TNC_ERROR)
 304                 {
 305                         continue;
 306                 }
 307
 308                 error_attr = (ietf_attr_pa_tnc_error_t*)attr;
 309                 error_code = error_attr->get_error_code(error_attr);
 310                 msg_info = error_attr->get_msg_info(error_attr);
 311                 DBG1(DBG_IMC, "received PA-TNC error '%N' concerning message %#B",
 312                          pa_tnc_error_code_names, error_code, &msg_info);
 313
 314                 switch (error_code)
 315                 {
 316                         case PA_ERROR_INVALID_PARAMETER:
 317                                 offset = error_attr->get_offset(error_attr);
 318                                 DBG1(DBG_IMC, "  occurred at offset of %u bytes", offset);
 319                                 break;
 320                         case PA_ERROR_ATTR_TYPE_NOT_SUPPORTED:
 321                                 attr_info = error_attr->get_attr_info(error_attr);
 322                                 DBG1(DBG_IMC, "  unsupported attribute %#B", &attr_info);
 323                                 break;
 324                         default:
 325                                 break;
 326                 }
 327                 fatal_error = TRUE;
 328         }
 329         enumerator->destroy(enumerator);
 330         pa_tnc_msg->destroy(pa_tnc_msg);
 331
 332         /* if no error occurred then always return the same response */
 333         return fatal_error ? TNC_RESULT_FATAL : send_message(connection_id);
 334 }
 335
 336 /**
 337  * see section 3.7.5 of TCG TNC IF-IMC Specification 1.2
 338  */
 339 TNC_Result TNC_IMC_BatchEnding(TNC_IMCID imc_id,
 340                                                            TNC_ConnectionID connection_id)
 341 {
 342         if (!imc_scanner)
 343         {
 344                 DBG1(DBG_IMC, "IMC \"%s\" has not been initialized", imc_name);
 345                 return TNC_RESULT_NOT_INITIALIZED;
 346         }
 347         return TNC_RESULT_SUCCESS;
 348 }
 349
 350 /**
 351  * see section 3.7.6 of TCG TNC IF-IMC Specification 1.2
 352  */
 353 TNC_Result TNC_IMC_Terminate(TNC_IMCID imc_id)
 354 {
 355         if (!imc_scanner)
 356         {
 357                 DBG1(DBG_IMC, "IMC \"%s\" has not been initialized", imc_name);
 358                 return TNC_RESULT_NOT_INITIALIZED;
 359         }
 360         imc_scanner->destroy(imc_scanner);
 361         imc_scanner = NULL;
 362
 363         return TNC_RESULT_SUCCESS;
 364 }
 365
 366 /**
 367  * see section 4.2.8.1 of TCG TNC IF-IMC Specification 1.2
 368  */
 369 TNC_Result TNC_IMC_ProvideBindFunction(TNC_IMCID imc_id,
 370                                                                            TNC_TNCC_BindFunctionPointer bind_function)
 371 {
 372         if (!imc_scanner)
 373         {
 374                 DBG1(DBG_IMC, "IMC \"%s\" has not been initialized", imc_name);
 375                 return TNC_RESULT_NOT_INITIALIZED;
 376         }
 377         return imc_scanner->bind_functions(imc_scanner, bind_function);
 378 }