src/libcharon/sa/ikev2/tasks/child_rekey.c

   1 /*
   2  * Copyright (C) 2005-2007 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 "child_rekey.h"
  18
  19 #include <daemon.h>
  20 #include <encoding/payloads/notify_payload.h>
  21 #include <sa/ikev2/tasks/child_create.h>
  22 #include <sa/ikev2/tasks/child_delete.h>
  23 #include <processing/jobs/rekey_child_sa_job.h>
  24 #include <processing/jobs/rekey_ike_sa_job.h>
  25
  26
  27 typedef struct private_child_rekey_t private_child_rekey_t;
  28
  29 /**
  30  * Private members of a child_rekey_t task.
  31  */
  32 struct private_child_rekey_t {
  33
  34         /**
  35          * Public methods and task_t interface.
  36          */
  37         child_rekey_t public;
  38
  39         /**
  40          * Assigned IKE_SA.
  41          */
  42         ike_sa_t *ike_sa;
  43
  44         /**
  45          * Are we the initiator?
  46          */
  47         bool initiator;
  48
  49         /**
  50          * Protocol of CHILD_SA to rekey
  51          */
  52         protocol_id_t protocol;
  53
  54         /**
  55          * Inbound SPI of CHILD_SA to rekey
  56          */
  57         u_int32_t spi;
  58
  59         /**
  60          * the CHILD_CREATE task which is reused to simplify rekeying
  61          */
  62         child_create_t *child_create;
  63
  64         /**
  65          * the CHILD_DELETE task to delete rekeyed CHILD_SA
  66          */
  67         child_delete_t *child_delete;
  68
  69         /**
  70          * CHILD_SA which gets rekeyed
  71          */
  72         child_sa_t *child_sa;
  73
  74         /**
  75          * colliding task, may be delete or rekey
  76          */
  77         task_t *collision;
  78
  79         /**
  80          * Indicate that peer destroyed the redundant child from collision.
  81          * This happens if a peer's delete notification for the redundant
  82          * child gets processed before the rekey job. If so, we must not
  83          * touch the child created in the collision since it points to
  84          * memory already freed.
  85          */
  86         bool other_child_destroyed;
  87 };
  88
  89 /**
  90  * Schedule a retry if rekeying temporary failed
  91  */
  92 static void schedule_delayed_rekey(private_child_rekey_t *this)
  93 {
  94         u_int32_t retry;
  95         job_t *job;
  96
  97         retry = RETRY_INTERVAL - (random() % RETRY_JITTER);
  98         job = (job_t*)rekey_child_sa_job_create(
  99                                                 this->child_sa->get_protocol(this->child_sa),
 100                                                 this->child_sa->get_spi(this->child_sa, TRUE),
 101                                                 this->ike_sa->get_my_host(this->ike_sa));
 102         DBG1(DBG_IKE, "CHILD_SA rekeying failed, trying again in %d seconds", retry);
 103         this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
 104         lib->scheduler->schedule_job(lib->scheduler, job, retry);
 105 }
 106
 107 /**
 108  * Implementation of task_t.build for initiator, after rekeying
 109  */
 110 static status_t build_i_delete(private_child_rekey_t *this, message_t *message)
 111 {
 112         /* update exchange type to INFORMATIONAL for the delete */
 113         message->set_exchange_type(message, INFORMATIONAL);
 114
 115         return this->child_delete->task.build(&this->child_delete->task, message);
 116 }
 117
 118 /**
 119  * Implementation of task_t.process for initiator, after rekeying
 120  */
 121 static status_t process_i_delete(private_child_rekey_t *this, message_t *message)
 122 {
 123         return this->child_delete->task.process(&this->child_delete->task, message);
 124 }
 125
 126 /**
 127  * find a child using the REKEY_SA notify
 128  */
 129 static void find_child(private_child_rekey_t *this, message_t *message)
 130 {
 131         notify_payload_t *notify;
 132         protocol_id_t protocol;
 133         u_int32_t spi;
 134
 135         notify = message->get_notify(message, REKEY_SA);
 136         if (notify)
 137         {
 138                 protocol = notify->get_protocol_id(notify);
 139                 spi = notify->get_spi(notify);
 140
 141                 if (protocol == PROTO_ESP || protocol == PROTO_AH)
 142                 {
 143                         this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, protocol,
 144                                                                                                                 spi, FALSE);
 145                 }
 146         }
 147 }
 148
 149 METHOD(task_t, build_i, status_t,
 150         private_child_rekey_t *this, message_t *message)
 151 {
 152         notify_payload_t *notify;
 153         u_int32_t reqid;
 154         child_cfg_t *config;
 155
 156         this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, this->protocol,
 157                                                                                                 this->spi, TRUE);
 158         if (!this->child_sa)
 159         {       /* check if it is an outbound CHILD_SA */
 160                 this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, this->protocol,
 161                                                                                                         this->spi, FALSE);
 162                 if (!this->child_sa)
 163                 {       /* CHILD_SA is gone, unable to rekey. As an empty CREATE_CHILD_SA
 164                          * exchange is invalid, we fall back to an INFORMATIONAL exchange.*/
 165                         message->set_exchange_type(message, INFORMATIONAL);
 166                         return SUCCESS;
 167                 }
 168                 /* we work only with the inbound SPI */
 169                 this->spi = this->child_sa->get_spi(this->child_sa, TRUE);
 170         }
 171         config = this->child_sa->get_config(this->child_sa);
 172
 173
 174         /* our CHILD_CREATE task does the hard work for us */
 175         if (!this->child_create)
 176         {
 177                 this->child_create = child_create_create(this->ike_sa,
 178                                                                         config->get_ref(config), TRUE, NULL, NULL);
 179         }
 180         reqid = this->child_sa->get_reqid(this->child_sa);
 181         this->child_create->use_reqid(this->child_create, reqid);
 182         this->child_create->use_marks(this->child_create,
 183                                                 this->child_sa->get_mark(this->child_sa, TRUE).value,
 184                                                 this->child_sa->get_mark(this->child_sa, FALSE).value);
 185
 186         if (this->child_create->task.build(&this->child_create->task,
 187                                                                            message) != NEED_MORE)
 188         {
 189                 schedule_delayed_rekey(this);
 190                 return FAILED;
 191         }
 192         if (message->get_exchange_type(message) == CREATE_CHILD_SA)
 193         {
 194                 /* don't add the notify if the CHILD_CREATE task changed the exchange */
 195                 notify = notify_payload_create_from_protocol_and_type(PLV2_NOTIFY,
 196                                                                                                         this->protocol, REKEY_SA);
 197                 notify->set_spi(notify, this->spi);
 198                 message->add_payload(message, (payload_t*)notify);
 199         }
 200         this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
 201
 202         return NEED_MORE;
 203 }
 204
 205 METHOD(task_t, process_r, status_t,
 206         private_child_rekey_t *this, message_t *message)
 207 {
 208         /* let the CHILD_CREATE task process the message */
 209         this->child_create->task.process(&this->child_create->task, message);
 210
 211         find_child(this, message);
 212
 213         return NEED_MORE;
 214 }
 215
 216 METHOD(task_t, build_r, status_t,
 217         private_child_rekey_t *this, message_t *message)
 218 {
 219         child_cfg_t *config;
 220         u_int32_t reqid;
 221
 222         if (this->child_sa == NULL ||
 223                 this->child_sa->get_state(this->child_sa) == CHILD_DELETING)
 224         {
 225                 DBG1(DBG_IKE, "unable to rekey, CHILD_SA not found");
 226                 message->add_notify(message, TRUE, NO_PROPOSAL_CHOSEN, chunk_empty);
 227                 return SUCCESS;
 228         }
 229
 230         /* let the CHILD_CREATE task build the response */
 231         reqid = this->child_sa->get_reqid(this->child_sa);
 232         this->child_create->use_reqid(this->child_create, reqid);
 233         this->child_create->use_marks(this->child_create,
 234                                                 this->child_sa->get_mark(this->child_sa, TRUE).value,
 235                                                 this->child_sa->get_mark(this->child_sa, FALSE).value);
 236         config = this->child_sa->get_config(this->child_sa);
 237         this->child_create->set_config(this->child_create, config->get_ref(config));
 238         this->child_create->task.build(&this->child_create->task, message);
 239
 240         if (message->get_payload(message, PLV2_SECURITY_ASSOCIATION) == NULL)
 241         {
 242                 /* rekeying failed, reuse old child */
 243                 this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
 244                 return SUCCESS;
 245         }
 246
 247         this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
 248
 249         /* invoke rekey hook */
 250         charon->bus->child_rekey(charon->bus, this->child_sa,
 251                                                          this->child_create->get_child(this->child_create));
 252         return SUCCESS;
 253 }
 254
 255 /**
 256  * Handle a rekey collision
 257  */
 258 static child_sa_t *handle_collision(private_child_rekey_t *this)
 259 {
 260         child_sa_t *to_delete;
 261
 262         if (this->collision->get_type(this->collision) == TASK_CHILD_REKEY)
 263         {
 264                 chunk_t this_nonce, other_nonce;
 265                 private_child_rekey_t *other = (private_child_rekey_t*)this->collision;
 266
 267                 this_nonce = this->child_create->get_lower_nonce(this->child_create);
 268                 other_nonce = other->child_create->get_lower_nonce(other->child_create);
 269
 270                 /* if we have the lower nonce, delete rekeyed SA. If not, delete
 271                  * the redundant. */
 272                 if (memcmp(this_nonce.ptr, other_nonce.ptr,
 273                                    min(this_nonce.len, other_nonce.len)) > 0)
 274                 {
 275                         child_sa_t *child_sa;
 276
 277                         DBG1(DBG_IKE, "CHILD_SA rekey collision won, deleting old child");
 278                         to_delete = this->child_sa;
 279                         /* don't touch child other created, it has already been deleted */
 280                         if (!this->other_child_destroyed)
 281                         {
 282                                 /* disable close action and updown event for redundant child */
 283                                 child_sa = other->child_create->get_child(other->child_create);
 284                                 if (child_sa)
 285                                 {
 286                                         child_sa->set_close_action(child_sa, ACTION_NONE);
 287                                         if (child_sa->get_state(child_sa) != CHILD_REKEYING)
 288                                         {
 289                                                 child_sa->set_state(child_sa, CHILD_REKEYING);
 290                                         }
 291                                 }
 292                         }
 293                 }
 294                 else
 295                 {
 296                         DBG1(DBG_IKE, "CHILD_SA rekey collision lost, "
 297                                  "deleting rekeyed child");
 298                         to_delete = this->child_create->get_child(this->child_create);
 299                 }
 300         }
 301         else
 302         {       /* CHILD_DELETE */
 303                 child_delete_t *del = (child_delete_t*)this->collision;
 304
 305                 /* we didn't had a chance to compare the nonces, so we delete
 306                  * the CHILD_SA the other is not deleting. */
 307                 if (del->get_child(del) != this->child_sa)
 308                 {
 309                         DBG1(DBG_IKE, "CHILD_SA rekey/delete collision, "
 310                                  "deleting rekeyed child");
 311                         to_delete = this->child_sa;
 312                 }
 313                 else
 314                 {
 315                         DBG1(DBG_IKE, "CHILD_SA rekey/delete collision, "
 316                                  "deleting redundant child");
 317                         to_delete = this->child_create->get_child(this->child_create);
 318                 }
 319         }
 320         return to_delete;
 321 }
 322
 323 METHOD(task_t, process_i, status_t,
 324         private_child_rekey_t *this, message_t *message)
 325 {
 326         protocol_id_t protocol;
 327         u_int32_t spi;
 328         child_sa_t *to_delete;
 329
 330         if (message->get_notify(message, NO_ADDITIONAL_SAS))
 331         {
 332                 DBG1(DBG_IKE, "peer seems to not support CHILD_SA rekeying, "
 333                          "starting reauthentication");
 334                 this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
 335                 lib->processor->queue_job(lib->processor,
 336                                 (job_t*)rekey_ike_sa_job_create(
 337                                                         this->ike_sa->get_id(this->ike_sa), TRUE));
 338                 return SUCCESS;
 339         }
 340
 341         if (this->child_create->task.process(&this->child_create->task,
 342                                                                                  message) == NEED_MORE)
 343         {
 344                 /* bad DH group while rekeying, retry, or failure requiring deletion */
 345                 return NEED_MORE;
 346         }
 347         if (message->get_payload(message, PLV2_SECURITY_ASSOCIATION) == NULL)
 348         {
 349                 /* establishing new child failed, reuse old. but not when we
 350                  * received a delete in the meantime */
 351                 if (!(this->collision &&
 352                           this->collision->get_type(this->collision) == TASK_CHILD_DELETE))
 353                 {
 354                         schedule_delayed_rekey(this);
 355                 }
 356                 return SUCCESS;
 357         }
 358
 359         /* check for rekey collisions */
 360         if (this->collision)
 361         {
 362                 to_delete = handle_collision(this);
 363         }
 364         else
 365         {
 366                 to_delete = this->child_sa;
 367         }
 368
 369         if (to_delete != this->child_create->get_child(this->child_create))
 370         {       /* invoke rekey hook if rekeying successful */
 371                 charon->bus->child_rekey(charon->bus, this->child_sa,
 372                                                         this->child_create->get_child(this->child_create));
 373         }
 374
 375         if (to_delete == NULL)
 376         {
 377                 return SUCCESS;
 378         }
 379         /* disable updown event for redundant CHILD_SA */
 380         if (to_delete->get_state(to_delete) != CHILD_REKEYING)
 381         {
 382                 to_delete->set_state(to_delete, CHILD_REKEYING);
 383         }
 384         spi = to_delete->get_spi(to_delete, TRUE);
 385         protocol = to_delete->get_protocol(to_delete);
 386
 387         /* rekeying done, delete the obsolete CHILD_SA using a subtask */
 388         this->child_delete = child_delete_create(this->ike_sa, protocol, spi, FALSE);
 389         this->public.task.build = (status_t(*)(task_t*,message_t*))build_i_delete;
 390         this->public.task.process = (status_t(*)(task_t*,message_t*))process_i_delete;
 391
 392         return NEED_MORE;
 393 }
 394
 395 METHOD(task_t, get_type, task_type_t,
 396         private_child_rekey_t *this)
 397 {
 398         return TASK_CHILD_REKEY;
 399 }
 400
 401 METHOD(child_rekey_t, collide, void,
 402         private_child_rekey_t *this, task_t *other)
 403 {
 404         /* the task manager only detects exchange collision, but not if
 405          * the collision is for the same child. we check it here. */
 406         if (other->get_type(other) == TASK_CHILD_REKEY)
 407         {
 408                 private_child_rekey_t *rekey = (private_child_rekey_t*)other;
 409                 if (rekey->child_sa != this->child_sa)
 410                 {
 411                         /* not the same child => no collision */
 412                         other->destroy(other);
 413                         return;
 414                 }
 415         }
 416         else if (other->get_type(other) == TASK_CHILD_DELETE)
 417         {
 418                 child_delete_t *del = (child_delete_t*)other;
 419                 if (this->collision &&
 420                         this->collision->get_type(this->collision) == TASK_CHILD_REKEY)
 421                 {
 422                         private_child_rekey_t *rekey;
 423
 424                         rekey = (private_child_rekey_t*)this->collision;
 425                         if (del->get_child(del) == rekey->child_create->get_child(rekey->child_create))
 426                         {
 427                                 /* peer deletes redundant child created in collision */
 428                                 this->other_child_destroyed = TRUE;
 429                                 other->destroy(other);
 430                                 return;
 431                         }
 432                 }
 433                 if (del->get_child(del) != this->child_sa)
 434                 {
 435                         /* not the same child => no collision */
 436                         other->destroy(other);
 437                         return;
 438                 }
 439         }
 440         else
 441         {
 442                 /* any other task is not critical for collisisions, ignore */
 443                 other->destroy(other);
 444                 return;
 445         }
 446         DBG1(DBG_IKE, "detected %N collision with %N", task_type_names,
 447                  TASK_CHILD_REKEY, task_type_names, other->get_type(other));
 448         DESTROY_IF(this->collision);
 449         this->collision = other;
 450 }
 451
 452 METHOD(task_t, migrate, void,
 453         private_child_rekey_t *this, ike_sa_t *ike_sa)
 454 {
 455         if (this->child_create)
 456         {
 457                 this->child_create->task.migrate(&this->child_create->task, ike_sa);
 458         }
 459         if (this->child_delete)
 460         {
 461                 this->child_delete->task.migrate(&this->child_delete->task, ike_sa);
 462         }
 463         DESTROY_IF(this->collision);
 464
 465         this->ike_sa = ike_sa;
 466         this->collision = NULL;
 467 }
 468
 469 METHOD(task_t, destroy, void,
 470         private_child_rekey_t *this)
 471 {
 472         if (this->child_create)
 473         {
 474                 this->child_create->task.destroy(&this->child_create->task);
 475         }
 476         if (this->child_delete)
 477         {
 478                 this->child_delete->task.destroy(&this->child_delete->task);
 479         }
 480         DESTROY_IF(this->collision);
 481         free(this);
 482 }
 483
 484 /*
 485  * Described in header.
 486  */
 487 child_rekey_t *child_rekey_create(ike_sa_t *ike_sa, protocol_id_t protocol,
 488                                                                   u_int32_t spi)
 489 {
 490         private_child_rekey_t *this;
 491
 492         INIT(this,
 493                 .public = {
 494                         .task = {
 495                                 .get_type = _get_type,
 496                                 .migrate = _migrate,
 497                                 .destroy = _destroy,
 498                         },
 499                         .collide = _collide,
 500                 },
 501                 .ike_sa = ike_sa,
 502                 .protocol = protocol,
 503                 .spi = spi,
 504         );
 505
 506         if (protocol != PROTO_NONE)
 507         {
 508                 this->public.task.build = _build_i;
 509                 this->public.task.process = _process_i;
 510                 this->initiator = TRUE;
 511                 this->child_create = NULL;
 512         }
 513         else
 514         {
 515                 this->public.task.build = _build_r;
 516                 this->public.task.process = _process_r;
 517                 this->initiator = FALSE;
 518                 this->child_create = child_create_create(ike_sa, NULL, TRUE, NULL, NULL);
 519         }
 520
 521         return &this->public;
 522 }