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
 106         /* Open a pipe stream for reading the output of the netstat commmand */
 107         file = popen("/bin/netstat -n -l -4 -6 --inet", "r");
 108         if (!file)
 109         {
 110                 DBG1(DBG_IMC, "Failed to run netstat command");
 111                 return FALSE;
 112         }
 113
 114         /* Read the output a line at a time */
 115         while (fgets(buf, BUF_LEN-1, file))
 116         {
 117                 u_char *pos;
 118                 u_int8_t new_protocol, protocol;
 119                 u_int16_t new_port, port;
 120                 int i;
 121                 enumerator_t *enumerator;
 122                 bool allowed, found = FALSE;
 123
 124                 DBG2(DBG_IMC, "%.*s", strlen(buf)-1, buf);
 125
 126                 if (n++ < 2)
 127                 {
 128                         /* skip the first two header lines */
 129                         continue;
 130                 }
 131                 line = chunk_create(buf, strlen(buf));
 132
 133                 /* Extract the IP protocol type */
 134                 if (!extract_token(&token, ' ', &line))
 135                 {
 136                         DBG1(DBG_IMC, "Protocol field in netstat output not found");
 137                         goto end;
 138                 }
 139                 if (match("tcp", &token) || match("tcp6", &token))
 140                 {
 141                         new_protocol = IPPROTO_TCP;
 142                 }
 143                 else if (match("udp", &token) || match("udp6", &token))
 144                 {
 145                         new_protocol = IPPROTO_UDP;
 146                 }
 147                 else
 148                 {
 149                         DBG1(DBG_IMC, "Skipped unknown IP protocol in netstat output");
 150                         continue;
 151                 }
 152
 153                 /* Skip the Recv-Q and Send-Q fields */
 154                 for (i = 0; i < 3; i++)
 155                 {
 156                         if (!eat_whitespace(&line) || !extract_token(&token, ' ', &line))
 157                         {
 158                                 token = chunk_empty;
 159                                 break;
 160                         }
 161                 }
 162                 if (token.len == 0)
 163                 {
 164                         DBG1(DBG_IMC, "Local Address field in netstat output not found");
 165                         goto end;
 166                 }
 167
 168                 /* Find the local port appended to the local address */
 169                 pos = token.ptr + token.len;
 170                 while (*--pos != ':' && --token.len);
 171                 if (*pos != ':')
 172                 {
 173                         DBG1(DBG_IMC, "Local port field in netstat output not found");
 174                         goto end;
 175                 }
 176
 177                 /* convert the port string to an integer */
 178                 new_port = atoi(pos+1);
 179
 180                 /* check if the there is already a port entry */
 181                 enumerator = attr->create_port_enumerator(attr);
 182                 while (enumerator->enumerate(enumerator, &allowed, &protocol, &port))
 183                 {
 184                         if (new_port == port && new_protocol == protocol)
 185                         {
 186                                 found = TRUE;
 187                         }
 188                 }
 189                 enumerator->destroy(enumerator);
 190
 191                 /* Skip the duplicate port entry */
 192                 if (found)
 193                 {
 194                         continue;
 195                 }
 196
 197                 /* Add new port entry */
 198                 attr->add_port(attr, FALSE, new_protocol, new_port);
 199         }
 200
 201         /* Successfully completed the parsing of the netstat output */
 202         success = TRUE;
 203
 204 end:
 205         /* Close the pipe stream */
 206         pclose(file);
 207         return success;
 208 }
 209
 210 static TNC_Result send_message(TNC_ConnectionID connection_id)
 211 {
 212         pa_tnc_msg_t *msg;
 213         pa_tnc_attr_t *attr;
 214         ietf_attr_port_filter_t *attr_port_filter;
 215         TNC_Result result;
 216
 217         attr = ietf_attr_port_filter_create();
 218         attr->set_noskip_flag(attr, TRUE);
 219         attr_port_filter = (ietf_attr_port_filter_t*)attr;
 220         if (!do_netstat(attr_port_filter))
 221         {
 222                 attr->destroy(attr);
 223                 return TNC_RESULT_FATAL;
 224         }
 225         msg = pa_tnc_msg_create();
 226         msg->add_attribute(msg, attr);
 227         msg->build(msg);
 228         result = imc_scanner->send_message(imc_scanner, connection_id,
 229                                                                            msg->get_encoding(msg));
 230         msg->destroy(msg);
 231
 232         return result;
 233 }
 234
 235 /**
 236  * see section 3.7.3 of TCG TNC IF-IMC Specification 1.2
 237  */
 238 TNC_Result TNC_IMC_BeginHandshake(TNC_IMCID imc_id,
 239                                                                   TNC_ConnectionID connection_id)
 240 {
 241         if (!imc_scanner)
 242         {
 243                 DBG1(DBG_IMC, "IMC \"%s\" has not been initialized", imc_name);
 244                 return TNC_RESULT_NOT_INITIALIZED;
 245         }
 246         return send_message(connection_id);
 247 }
 248
 249 /**
 250  * see section 3.7.4 of TCG TNC IF-IMC Specification 1.2
 251  */
 252 TNC_Result TNC_IMC_ReceiveMessage(TNC_IMCID imc_id,
 253                                                                   TNC_ConnectionID connection_id,
 254                                                                   TNC_BufferReference msg,
 255                                                                   TNC_UInt32 msg_len,
 256                                                                   TNC_MessageType msg_type)
 257 {
 258         pa_tnc_msg_t *pa_tnc_msg;
 259         pa_tnc_attr_t *attr;
 260         enumerator_t *enumerator;
 261         TNC_Result result;
 262         bool fatal_error = FALSE;
 263
 264         if (!imc_scanner)
 265         {
 266                 DBG1(DBG_IMC, "IMC \"%s\" has not been initialized", imc_name);
 267                 return TNC_RESULT_NOT_INITIALIZED;
 268         }
 269
 270         /* parse received PA-TNC message and automatically handle any errors */
 271         result = imc_scanner->receive_message(imc_scanner, connection_id,
 272                                                                            chunk_create(msg, msg_len), msg_type,
 273                                                                            &pa_tnc_msg);
 274
 275         /* no parsed PA-TNC attributes available if an error occurred */
 276         if (!pa_tnc_msg)
 277         {
 278                 return result;
 279         }
 280
 281         /* analyze PA-TNC attributes */
 282         enumerator = pa_tnc_msg->create_attribute_enumerator(pa_tnc_msg);
 283         while (enumerator->enumerate(enumerator, &attr))
 284         {
 285                 ietf_attr_pa_tnc_error_t *error_attr;
 286                 pa_tnc_error_code_t error_code;
 287                 chunk_t msg_info, attr_info;
 288
 289                 if (attr->get_vendor_id(attr) != PEN_IETF &&
 290                         attr->get_type(attr) != IETF_ATTR_PA_TNC_ERROR)
 291                 {
 292                         continue;
 293                 }
 294
 295                 error_attr = (ietf_attr_pa_tnc_error_t*)attr;
 296                 error_code = error_attr->get_error_code(error_attr);
 297                 msg_info = error_attr->get_msg_info(error_attr);
 298                 DBG1(DBG_IMC, "received PA-TNC error '%N' concerning message %#B",
 299                          pa_tnc_error_code_names, error_code, &msg_info);
 300
 301                 switch (error_code)
 302                 {
 303                         case PA_ERROR_ATTR_TYPE_NOT_SUPPORTED:
 304                                 attr_info = error_attr->get_attr_info(error_attr);
 305                                 DBG1(DBG_IMC, "  unsupported attribute %#B", &attr_info);
 306                                 break;
 307                         default:
 308                                 break;
 309                 }
 310                 fatal_error = TRUE;
 311         }
 312         enumerator->destroy(enumerator);
 313         pa_tnc_msg->destroy(pa_tnc_msg);
 314
 315         /* if no error occurred then always return the same response */
 316         return fatal_error ? TNC_RESULT_FATAL : send_message(connection_id);
 317 }
 318
 319 /**
 320  * see section 3.7.5 of TCG TNC IF-IMC Specification 1.2
 321  */
 322 TNC_Result TNC_IMC_BatchEnding(TNC_IMCID imc_id,
 323                                                            TNC_ConnectionID connection_id)
 324 {
 325         if (!imc_scanner)
 326         {
 327                 DBG1(DBG_IMC, "IMC \"%s\" has not been initialized", imc_name);
 328                 return TNC_RESULT_NOT_INITIALIZED;
 329         }
 330         return TNC_RESULT_SUCCESS;
 331 }
 332
 333 /**
 334  * see section 3.7.6 of TCG TNC IF-IMC Specification 1.2
 335  */
 336 TNC_Result TNC_IMC_Terminate(TNC_IMCID imc_id)
 337 {
 338         if (!imc_scanner)
 339         {
 340                 DBG1(DBG_IMC, "IMC \"%s\" has not been initialized", imc_name);
 341                 return TNC_RESULT_NOT_INITIALIZED;
 342         }
 343         imc_scanner->destroy(imc_scanner);
 344         imc_scanner = NULL;
 345
 346         return TNC_RESULT_SUCCESS;
 347 }
 348
 349 /**
 350  * see section 4.2.8.1 of TCG TNC IF-IMC Specification 1.2
 351  */
 352 TNC_Result TNC_IMC_ProvideBindFunction(TNC_IMCID imc_id,
 353                                                                            TNC_TNCC_BindFunctionPointer bind_function)
 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         return imc_scanner->bind_functions(imc_scanner, bind_function);
 361 }