src/libcharon/plugins/tnc_pdp/tnc_pdp.c

   1 /*
   2  * Copyright (C) 2012 Andreas Steffen
   3  * HSR Hochschule fuer Technik Rapperswil
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the
   7  * Free Software Foundation; either version 2 of the License, or (at your
   8  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  12  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * for more details.
  14  */
  15
  16 #include "tnc_pdp.h"
  17 #include "tnc_pdp_connections.h"
  18
  19 #include <errno.h>
  20 #include <unistd.h>
  21
  22 #include <radius_message.h>
  23
  24 #include <daemon.h>
  25 #include <debug.h>
  26 #include <threading/thread.h>
  27 #include <processing/jobs/callback_job.h>
  28 #include <sa/authenticators/eap/eap_method.h>
  29
  30 typedef struct private_tnc_pdp_t private_tnc_pdp_t;
  31
  32 /**
  33  * Maximum size of a RADIUS IP packet
  34  */
  35 #define MAX_PACKET 4096
  36
  37 /**
  38  * private data of tnc_pdp_t
  39  */
  40 struct private_tnc_pdp_t {
  41
  42         /**
  43          * implements tnc_pdp_t interface
  44          */
  45         tnc_pdp_t public;
  46
  47         /**
  48          * ID of the server
  49          */
  50         identification_t *server;
  51
  52         /**
  53          * EAP method type to be used
  54          */
  55         eap_type_t type;
  56
  57         /**
  58          * IPv4 RADIUS socket
  59          */
  60         int ipv4;
  61
  62         /**
  63          * IPv6 RADIUS socket
  64          */
  65         int ipv6;
  66
  67         /**
  68          * Callback job dispatching commands
  69          */
  70         callback_job_t *job;
  71
  72         /**
  73          * RADIUS shared secret
  74          */
  75         chunk_t secret;
  76
  77         /**
  78          * MD5 hasher
  79          */
  80         hasher_t *hasher;
  81
  82         /**
  83          * HMAC MD5 signer, with secret set
  84          */
  85         signer_t *signer;
  86
  87         /**
  88          * List of registered TNC-PDP connections
  89          */
  90         tnc_pdp_connections_t *connections;
  91 };
  92
  93
  94 /**
  95  * Open IPv4 or IPv6 UDP RADIUS socket
  96  */
  97 static int open_socket(private_tnc_pdp_t *this, int family, u_int16_t port)
  98 {
  99         int on = TRUE;
 100         struct sockaddr_storage addr;
 101         socklen_t addrlen;
 102         int skt;
 103
 104         memset(&addr, 0, sizeof(addr));
 105         addr.ss_family = family;
 106
 107         /* precalculate constants depending on address family */
 108         switch (family)
 109         {
 110                 case AF_INET:
 111                 {
 112                         struct sockaddr_in *sin = (struct sockaddr_in *)&addr;
 113
 114                         htoun32(&sin->sin_addr.s_addr, INADDR_ANY);
 115                         htoun16(&sin->sin_port, port);
 116                         addrlen = sizeof(struct sockaddr_in);
 117                         break;
 118                 }
 119                 case AF_INET6:
 120                 {
 121                         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&addr;
 122
 123                         memcpy(&sin6->sin6_addr, &in6addr_any, sizeof(in6addr_any));
 124                         htoun16(&sin6->sin6_port, port);
 125                         addrlen = sizeof(struct sockaddr_in6);
 126                         break;
 127                 }
 128                 default:
 129                         return 0;
 130         }
 131
 132         /* open the socket */
 133         skt = socket(family, SOCK_DGRAM, IPPROTO_UDP);
 134         if (skt < 0)
 135         {
 136                 DBG1(DBG_CFG, "opening RADIUS socket failed: %s", strerror(errno));
 137                 return 0;
 138         }
 139         if (setsockopt(skt, SOL_SOCKET, SO_REUSEADDR, (void*)&on, sizeof(on)) < 0)
 140         {
 141                 DBG1(DBG_CFG, "unable to set SO_REUSEADDR on socket: %s", strerror(errno));
 142                 close(skt);
 143                 return 0;
 144         }
 145
 146         /* bind the socket */
 147         if (bind(skt, (struct sockaddr *)&addr, addrlen) < 0)
 148         {
 149                 DBG1(DBG_CFG, "unable to bind RADIUS socket: %s", strerror(errno));
 150                 close(skt);
 151                 return 0;
 152         }
 153
 154         return skt;
 155 }
 156
 157 /**
 158  * Send a RADIUS message to client
 159  */
 160 static void send_message(private_tnc_pdp_t *this, radius_message_t *message,
 161                                                  host_t *client)
 162 {
 163         int fd;
 164         chunk_t data;
 165
 166         fd = (client->get_family(client) == AF_INET) ? this->ipv4 : this->ipv6;
 167         data = message->get_encoding(message);
 168
 169         DBG2(DBG_CFG, "sending RADIUS packet to %#H", client);
 170         DBG3(DBG_CFG, "%B", &data);
 171
 172         if (sendto(fd, data.ptr, data.len, 0, client->get_sockaddr(client),
 173                            *client->get_sockaddr_len(client)) != data.len)
 174         {
 175                 DBG1(DBG_CFG, "sending RADIUS message failed: %s", strerror(errno));
 176         }
 177 }
 178
 179 /**
 180  * Send a RADIUS response for a request
 181  */
 182 static void send_response(private_tnc_pdp_t *this,
 183                                                   radius_message_t *request, radius_message_code_t code,
 184                                                   eap_payload_t *eap, host_t *client)
 185 {
 186         radius_message_t *response;
 187         chunk_t data;
 188
 189         response = radius_message_create(code);
 190         if (eap)
 191         {
 192                 data = eap->get_data(eap);
 193                 DBG3(DBG_CFG, "%N payload %B", eap_type_names, this->type, &data);
 194
 195                 /* fragment data suitable for RADIUS */
 196                 while (data.len > MAX_RADIUS_ATTRIBUTE_SIZE)
 197                 {
 198                         response->add(response, RAT_EAP_MESSAGE,
 199                                                   chunk_create(data.ptr, MAX_RADIUS_ATTRIBUTE_SIZE));
 200                         data = chunk_skip(data, MAX_RADIUS_ATTRIBUTE_SIZE);
 201                 }
 202                 response->add(response, RAT_EAP_MESSAGE, data);
 203         }
 204         response->set_identifier(response, request->get_identifier(request));
 205         response->sign(response, request->get_authenticator(request),
 206                                    this->secret, this->hasher, this->signer, NULL, TRUE);
 207
 208         DBG1(DBG_CFG, "sending RADIUS %N to client '%H'", radius_message_code_names,
 209                  code, client);
 210         send_message(this, response, client);
 211         response->destroy(response);
 212 }
 213
 214 /**
 215  * Process EAP message
 216  */
 217 static void process_eap(private_tnc_pdp_t *this, radius_message_t *request,
 218                                                 host_t *source)
 219 {
 220         enumerator_t *enumerator;
 221         eap_payload_t *in, *out = NULL;
 222         eap_method_t *method;
 223         eap_type_t eap_type;
 224         chunk_t data, message = chunk_empty;
 225         chunk_t user_name = chunk_empty, nas_id = chunk_empty;
 226         radius_message_code_t code = RMC_ACCESS_CHALLENGE;
 227         u_int32_t eap_vendor;
 228         int type;
 229
 230         enumerator = request->create_enumerator(request);
 231         while (enumerator->enumerate(enumerator, &type, &data))
 232         {
 233                 switch (type)
 234                 {
 235                         case RAT_USER_NAME:
 236                                 user_name = data;
 237                                 break;
 238                         case RAT_NAS_IDENTIFIER:
 239                                 nas_id = data;
 240                                 break;
 241                         case RAT_EAP_MESSAGE:
 242                                 if (data.len)
 243                                 {
 244                                         message = chunk_cat("mc", message, data);
 245                                 }
 246                                 break;
 247                         default:
 248                                 break;
 249                 }
 250         }
 251         enumerator->destroy(enumerator);
 252
 253         if (message.len)
 254         {
 255                 in = eap_payload_create_data(message);
 256
 257                 /* apply EAP method selected by RADIUS server */
 258                 eap_type = in->get_type(in, &eap_vendor);
 259
 260                 DBG3(DBG_CFG, "%N payload %B", eap_type_names, eap_type, &message);
 261                 free(message.ptr);
 262
 263                 if (eap_type == EAP_IDENTITY)
 264                 {
 265                         identification_t *peer;
 266                         chunk_t eap_identity;
 267
 268                         if (message.len < 5)
 269                         {
 270                                 return;
 271                         }
 272                         eap_identity = chunk_create(message.ptr + 5, message.len - 5);
 273                         peer = identification_create_from_data(eap_identity);
 274
 275                         method = charon->eap->create_instance(charon->eap, this->type,
 276                                                                                 0, EAP_SERVER, this->server, peer);
 277                         peer->destroy(peer);
 278                         if (!method)
 279                         {
 280                                 in->destroy(in);
 281                                 return;
 282                         }
 283                         this->connections->add(this->connections, nas_id, user_name, method);
 284                         method->initiate(method, &out);
 285                 }
 286                 else
 287                 {
 288                         method = this->connections->get_method(this->connections, nas_id,
 289                                                                                                    user_name);
 290                         if (!method)
 291                         {
 292                                 return;
 293                         }
 294
 295                         switch (method->process(method, in, &out))
 296                         {
 297                                 case NEED_MORE:
 298                                         code = RMC_ACCESS_CHALLENGE;
 299                                         break;
 300                                 case SUCCESS:
 301                                         code = RMC_ACCESS_ACCEPT;
 302                                         DESTROY_IF(out);
 303                                         out = eap_payload_create_code(EAP_SUCCESS,
 304                                                                                                   in->get_identifier(in));
 305                                         break;
 306                                 case FAILED:
 307                                 default:
 308                                         code = RMC_ACCESS_REJECT;
 309                                         DESTROY_IF(out);
 310                                         out = eap_payload_create_code(EAP_FAILURE,
 311                                                                                                   in->get_identifier(in));
 312                         }
 313                 }
 314
 315                 if (code == RMC_ACCESS_ACCEPT || code == RMC_ACCESS_REJECT)
 316                 {
 317                         this->connections->remove(this->connections, nas_id, user_name);
 318                 }
 319
 320                 send_response(this, request, code, out, source);
 321                 in->destroy(in);
 322                 out->destroy(out);
 323         }
 324 }
 325
 326 /**
 327  * Process packets received on the RADIUS socket
 328  */
 329 static job_requeue_t receive(private_tnc_pdp_t *this)
 330 {
 331         while (TRUE)
 332         {
 333                 radius_message_t *request;
 334                 char buffer[MAX_PACKET];
 335                 int max_fd = 0, selected = 0, bytes_read = 0;
 336                 fd_set rfds;
 337                 bool oldstate;
 338                 host_t *source;
 339                 struct msghdr msg;
 340                 struct iovec iov;
 341                 union {
 342                         struct sockaddr_in in4;
 343                         struct sockaddr_in6 in6;
 344                 } src;
 345
 346                 FD_ZERO(&rfds);
 347
 348                 if (this->ipv4)
 349                 {
 350                         FD_SET(this->ipv4, &rfds);
 351                 }
 352                 if (this->ipv6)
 353                 {
 354                         FD_SET(this->ipv6, &rfds);
 355                 }
 356                 max_fd = max(this->ipv4, this->ipv6);
 357
 358                 DBG2(DBG_CFG, "waiting for data on RADIUS sockets");
 359                 oldstate = thread_cancelability(TRUE);
 360                 if (select(max_fd + 1, &rfds, NULL, NULL, NULL) <= 0)
 361                 {
 362                         thread_cancelability(oldstate);
 363                         continue;
 364                 }
 365                 thread_cancelability(oldstate);
 366
 367                 if (FD_ISSET(this->ipv4, &rfds))
 368                 {
 369                         selected = this->ipv4;
 370                 }
 371                 else if (FD_ISSET(this->ipv6, &rfds))
 372                 {
 373                         selected = this->ipv6;
 374                 }
 375                 else
 376                 {
 377                         /* oops, shouldn't happen */
 378                         continue;
 379                 }
 380
 381                 /* read received packet */
 382                 msg.msg_name = &src;
 383                 msg.msg_namelen = sizeof(src);
 384                 iov.iov_base = buffer;
 385                 iov.iov_len = MAX_PACKET;
 386                 msg.msg_iov = &iov;
 387                 msg.msg_iovlen = 1;
 388                 msg.msg_flags = 0;
 389
 390                 bytes_read = recvmsg(selected, &msg, 0);
 391                 if (bytes_read < 0)
 392                 {
 393                         DBG1(DBG_CFG, "error reading RADIUS socket: %s", strerror(errno));
 394                         continue;
 395                 }
 396                 if (msg.msg_flags & MSG_TRUNC)
 397                 {
 398                         DBG1(DBG_CFG, "receive buffer too small, RADIUS packet discarded");
 399                         continue;
 400                 }
 401                 source = host_create_from_sockaddr((sockaddr_t*)&src);
 402                 DBG2(DBG_CFG, "received RADIUS packet from %#H", source);
 403                 DBG3(DBG_CFG, "%b", buffer, bytes_read);
 404                 request = radius_message_parse(chunk_create(buffer, bytes_read));
 405                 if (request)
 406                 {
 407                         DBG1(DBG_CFG, "received RADIUS %N from client '%H'",
 408                                  radius_message_code_names, request->get_code(request), source);
 409
 410                         if (request->verify(request, NULL, this->secret, this->hasher,
 411                                                                                            this->signer))
 412                         {
 413                                 process_eap(this, request, source);
 414                         }
 415                         request->destroy(request);
 416
 417                 }
 418                 else
 419                 {
 420                         DBG1(DBG_CFG, "received invalid RADIUS message, ignored");
 421                 }
 422                 source->destroy(source);
 423         }
 424         return JOB_REQUEUE_FAIR;
 425 }
 426
 427 METHOD(tnc_pdp_t, destroy, void,
 428         private_tnc_pdp_t *this)
 429 {
 430         if (this->job)
 431         {
 432                 this->job->cancel(this->job);
 433         }
 434         if (this->ipv4)
 435         {
 436                 close(this->ipv4);
 437         }
 438         if (this->ipv6)
 439         {
 440                 close(this->ipv6);
 441         }
 442         DESTROY_IF(this->server);
 443         DESTROY_IF(this->signer);
 444         DESTROY_IF(this->hasher);
 445         DESTROY_IF(this->connections);
 446         free(this);
 447 }
 448
 449 /*
 450  * see header file
 451  */
 452 tnc_pdp_t *tnc_pdp_create(u_int16_t port)
 453 {
 454         private_tnc_pdp_t *this;
 455         char *secret, *server;
 456
 457         INIT(this,
 458                 .public = {
 459                         .destroy = _destroy,
 460                 },
 461                 .type = EAP_TTLS,
 462                 .ipv4 = open_socket(this, AF_INET,  port),
 463                 .ipv6 = open_socket(this, AF_INET6, port),
 464                 .hasher = lib->crypto->create_hasher(lib->crypto, HASH_MD5),
 465                 .signer = lib->crypto->create_signer(lib->crypto, AUTH_HMAC_MD5_128),
 466                 .connections = tnc_pdp_connections_create(),
 467         );
 468
 469         if (!this->ipv4 && !this->ipv6)
 470         {
 471                 DBG1(DBG_NET, "couldd not create any RADIUS sockets");
 472                 destroy(this);
 473                 return NULL;
 474         }
 475         if (!this->ipv4)
 476         {
 477                 DBG1(DBG_NET, "could not open IPv4 RADIUS socket, IPv4 disabled");
 478         }
 479         if (!this->ipv6)
 480         {
 481                 DBG1(DBG_NET, "could not open IPv6 RADIUS socket, IPv6 disabled");
 482         }
 483         if (!this->hasher || !this->signer)
 484         {
 485                 destroy(this);
 486                 return NULL;
 487         }
 488
 489         server = lib->settings->get_str(lib->settings,
 490                                                 "charon.plugins.tnc-pdp.server", NULL);
 491         if (!server)
 492         {
 493                 DBG1(DBG_CFG, "missing PDP server name, PDP disabled");
 494                 destroy(this);
 495                 return NULL;
 496         }
 497         this->server = identification_create_from_string(server);
 498
 499         secret = lib->settings->get_str(lib->settings,
 500                                                 "charon.plugins.tnc-pdp.secret", NULL);
 501         if (!secret)
 502         {
 503                 DBG1(DBG_CFG, "missing RADIUS secret, PDP disabled");
 504                 destroy(this);
 505                 return NULL;
 506         }
 507         this->secret = chunk_create(secret, strlen(secret));
 508         this->signer->set_key(this->signer, this->secret);
 509
 510
 511         this->job = callback_job_create_with_prio((callback_job_cb_t)receive,
 512                                                                                 this, NULL, NULL, JOB_PRIO_CRITICAL);
 513         lib->processor->queue_job(lib->processor, (job_t*)this->job);
 514
 515         return &this->public;
 516 }
 517