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

   1 /*
   2  * Copyright (C) 2009-2016 Tobias Brunner
   3  * Copyright (C) 2005-2007 Martin Willi
   4  * Copyright (C) 2005 Jan Hutter
   5  * HSR Hochschule fuer Technik Rapperswil
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License as published by the
   9  * Free Software Foundation; either version 2 of the License, or (at your
  10  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  14  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15  * for more details.
  16  */
  17
  18 #include "child_rekey.h"
  19
  20 #include <daemon.h>
  21 #include <encoding/payloads/notify_payload.h>
  22 #include <sa/ikev2/tasks/child_create.h>
  23 #include <sa/ikev2/tasks/child_delete.h>
  24 #include <processing/jobs/rekey_child_sa_job.h>
  25 #include <processing/jobs/rekey_ike_sa_job.h>
  26
  27
  28 typedef struct private_child_rekey_t private_child_rekey_t;
  29
  30 /**
  31  * Private members of a child_rekey_t task.
  32  */
  33 struct private_child_rekey_t {
  34
  35         /**
  36          * Public methods and task_t interface.
  37          */
  38         child_rekey_t public;
  39
  40         /**
  41          * Assigned IKE_SA.
  42          */
  43         ike_sa_t *ike_sa;
  44
  45         /**
  46          * Are we the initiator?
  47          */
  48         bool initiator;
  49
  50         /**
  51          * Protocol of CHILD_SA to rekey
  52          */
  53         protocol_id_t protocol;
  54
  55         /**
  56          * Inbound SPI of CHILD_SA to rekey
  57          */
  58         uint32_t spi;
  59
  60         /**
  61          * the CHILD_CREATE task which is reused to simplify rekeying
  62          */
  63         child_create_t *child_create;
  64
  65         /**
  66          * the CHILD_DELETE task to delete rekeyed CHILD_SA
  67          */
  68         child_delete_t *child_delete;
  69
  70         /**
  71          * CHILD_SA which gets rekeyed
  72          */
  73         child_sa_t *child_sa;
  74
  75         /**
  76          * colliding task, may be delete or rekey
  77          */
  78         task_t *collision;
  79
  80         /**
  81          * Indicate that peer destroyed the redundant child from collision.
  82          * This happens if a peer's delete notification for the redundant
  83          * child gets processed before the rekey job. If so, we must not
  84          * touch the child created in the collision since it points to
  85          * memory already freed.
  86          */
  87         bool other_child_destroyed;
  88 };
  89
  90 /**
  91  * Schedule a retry if rekeying temporary failed
  92  */
  93 static void schedule_delayed_rekey(private_child_rekey_t *this)
  94 {
  95         uint32_t retry;
  96         job_t *job;
  97
  98         retry = RETRY_INTERVAL - (random() % RETRY_JITTER);
  99         job = (job_t*)rekey_child_sa_job_create(
 100                                                 this->child_sa->get_protocol(this->child_sa),
 101                                                 this->child_sa->get_spi(this->child_sa, TRUE),
 102                                                 this->ike_sa->get_my_host(this->ike_sa));
 103         DBG1(DBG_IKE, "CHILD_SA rekeying failed, trying again in %d seconds", retry);
 104         this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
 105         lib->scheduler->schedule_job(lib->scheduler, job, retry);
 106 }
 107
 108 /**
 109  * Implementation of task_t.build for initiator, after rekeying
 110  */
 111 static status_t build_i_delete(private_child_rekey_t *this, message_t *message)
 112 {
 113         /* update exchange type to INFORMATIONAL for the delete */
 114         message->set_exchange_type(message, INFORMATIONAL);
 115
 116         return this->child_delete->task.build(&this->child_delete->task, message);
 117 }
 118
 119 /**
 120  * Implementation of task_t.process for initiator, after rekeying
 121  */
 122 static status_t process_i_delete(private_child_rekey_t *this, message_t *message)
 123 {
 124         return this->child_delete->task.process(&this->child_delete->task, message);
 125 }
 126
 127 /**
 128  * find a child using the REKEY_SA notify
 129  */
 130 static void find_child(private_child_rekey_t *this, message_t *message)
 131 {
 132         notify_payload_t *notify;
 133         protocol_id_t protocol;
 134         uint32_t spi;
 135         child_sa_t *child_sa;
 136
 137         notify = message->get_notify(message, REKEY_SA);
 138         if (notify)
 139         {
 140                 protocol = notify->get_protocol_id(notify);
 141                 spi = notify->get_spi(notify);
 142
 143                 if (protocol == PROTO_ESP || protocol == PROTO_AH)
 144                 {
 145                         child_sa = this->ike_sa->get_child_sa(this->ike_sa, protocol,
 146                                                                                                   spi, FALSE);
 147                         if (child_sa &&
 148                                 child_sa->get_state(child_sa) == CHILD_DELETING &&
 149                                 child_sa->get_outbound_state(child_sa) == CHILD_OUTBOUND_NONE)
 150                         {       /* ignore rekeyed CHILD_SAs we keep around */
 151                                 return;
 152                         }
 153                         this->child_sa = child_sa;
 154                 }
 155         }
 156 }
 157
 158 METHOD(task_t, build_i, status_t,
 159         private_child_rekey_t *this, message_t *message)
 160 {
 161         notify_payload_t *notify;
 162         uint32_t reqid;
 163         child_cfg_t *config;
 164
 165         this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, this->protocol,
 166                                                                                                 this->spi, TRUE);
 167         if (!this->child_sa)
 168         {       /* check if it is an outbound CHILD_SA */
 169                 this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, this->protocol,
 170                                                                                                         this->spi, FALSE);
 171                 if (this->child_sa)
 172                 {
 173                         /* we work only with the inbound SPI */
 174                         this->spi = this->child_sa->get_spi(this->child_sa, TRUE);
 175                 }
 176         }
 177         if (!this->child_sa ||
 178                 (!this->child_create &&
 179                   this->child_sa->get_state(this->child_sa) != CHILD_INSTALLED) ||
 180                 (this->child_create &&
 181                  this->child_sa->get_state(this->child_sa) != CHILD_REKEYING))
 182         {
 183                 /* CHILD_SA is gone or in the wrong state, unable to rekey */
 184                 message->set_exchange_type(message, EXCHANGE_TYPE_UNDEFINED);
 185                 return SUCCESS;
 186         }
 187         config = this->child_sa->get_config(this->child_sa);
 188
 189
 190         /* our CHILD_CREATE task does the hard work for us */
 191         if (!this->child_create)
 192         {
 193                 this->child_create = child_create_create(this->ike_sa,
 194                                                                         config->get_ref(config), TRUE, NULL, NULL);
 195         }
 196         reqid = this->child_sa->get_reqid(this->child_sa);
 197         this->child_create->use_reqid(this->child_create, reqid);
 198         this->child_create->use_marks(this->child_create,
 199                                                 this->child_sa->get_mark(this->child_sa, TRUE).value,
 200                                                 this->child_sa->get_mark(this->child_sa, FALSE).value);
 201
 202         if (this->child_create->task.build(&this->child_create->task,
 203                                                                            message) != NEED_MORE)
 204         {
 205                 schedule_delayed_rekey(this);
 206                 return FAILED;
 207         }
 208         if (message->get_exchange_type(message) == CREATE_CHILD_SA)
 209         {
 210                 /* don't add the notify if the CHILD_CREATE task changed the exchange */
 211                 notify = notify_payload_create_from_protocol_and_type(PLV2_NOTIFY,
 212                                                                                                         this->protocol, REKEY_SA);
 213                 notify->set_spi(notify, this->spi);
 214                 message->add_payload(message, (payload_t*)notify);
 215         }
 216         this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
 217
 218         return NEED_MORE;
 219 }
 220
 221 METHOD(task_t, process_r, status_t,
 222         private_child_rekey_t *this, message_t *message)
 223 {
 224         /* let the CHILD_CREATE task process the message */
 225         this->child_create->task.process(&this->child_create->task, message);
 226
 227         find_child(this, message);
 228
 229         return NEED_MORE;
 230 }
 231
 232 METHOD(task_t, build_r, status_t,
 233         private_child_rekey_t *this, message_t *message)
 234 {
 235         child_cfg_t *config;
 236         uint32_t reqid;
 237         child_sa_state_t state;
 238         child_sa_t *child_sa;
 239
 240         if (!this->child_sa)
 241         {
 242                 DBG1(DBG_IKE, "unable to rekey, CHILD_SA not found");
 243                 message->add_notify(message, TRUE, CHILD_SA_NOT_FOUND, chunk_empty);
 244                 return SUCCESS;
 245         }
 246         if (this->child_sa->get_state(this->child_sa) == CHILD_DELETING)
 247         {
 248                 DBG1(DBG_IKE, "unable to rekey, we are deleting the CHILD_SA");
 249                 message->add_notify(message, TRUE, TEMPORARY_FAILURE, chunk_empty);
 250                 return SUCCESS;
 251         }
 252
 253         /* let the CHILD_CREATE task build the response */
 254         reqid = this->child_sa->get_reqid(this->child_sa);
 255         this->child_create->use_reqid(this->child_create, reqid);
 256         this->child_create->use_marks(this->child_create,
 257                                                 this->child_sa->get_mark(this->child_sa, TRUE).value,
 258                                                 this->child_sa->get_mark(this->child_sa, FALSE).value);
 259         config = this->child_sa->get_config(this->child_sa);
 260         this->child_create->set_config(this->child_create, config->get_ref(config));
 261         this->child_create->task.build(&this->child_create->task, message);
 262
 263         state = this->child_sa->get_state(this->child_sa);
 264         this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
 265
 266         if (message->get_payload(message, PLV2_SECURITY_ASSOCIATION) == NULL)
 267         {       /* rekeying failed, reuse old child */
 268                 this->child_sa->set_state(this->child_sa, state);
 269                 return SUCCESS;
 270         }
 271
 272         child_sa = this->child_create->get_child(this->child_create);
 273         this->child_sa->set_state(this->child_sa, CHILD_REKEYED);
 274         this->child_sa->set_rekey_spi(this->child_sa,
 275                                                                   child_sa->get_spi(child_sa, FALSE));
 276
 277         /* invoke rekey hook */
 278         charon->bus->child_rekey(charon->bus, this->child_sa,
 279                                                          this->child_create->get_child(this->child_create));
 280         return SUCCESS;
 281 }
 282
 283 /**
 284  * Handle a rekey collision
 285  */
 286 static child_sa_t *handle_collision(private_child_rekey_t *this)
 287 {
 288         child_sa_t *to_delete;
 289
 290         if (this->collision->get_type(this->collision) == TASK_CHILD_REKEY)
 291         {
 292                 chunk_t this_nonce, other_nonce;
 293                 private_child_rekey_t *other = (private_child_rekey_t*)this->collision;
 294
 295                 this_nonce = this->child_create->get_lower_nonce(this->child_create);
 296                 other_nonce = other->child_create->get_lower_nonce(other->child_create);
 297
 298                 /* if we have the lower nonce, delete rekeyed SA. If not, delete
 299                  * the redundant. */
 300                 if (memcmp(this_nonce.ptr, other_nonce.ptr,
 301                                    min(this_nonce.len, other_nonce.len)) > 0)
 302                 {
 303                         child_sa_t *child_sa;
 304
 305                         DBG1(DBG_IKE, "CHILD_SA rekey collision won, deleting old child");
 306                         to_delete = this->child_sa;
 307                         /* don't touch child other created, it has already been deleted */
 308                         if (!this->other_child_destroyed)
 309                         {
 310                                 /* disable close action and updown event for redundant child */
 311                                 child_sa = other->child_create->get_child(other->child_create);
 312                                 if (child_sa)
 313                                 {
 314                                         child_sa->set_close_action(child_sa, ACTION_NONE);
 315                                         if (child_sa->get_state(child_sa) != CHILD_REKEYED)
 316                                         {
 317                                                 child_sa->set_state(child_sa, CHILD_REKEYED);
 318                                         }
 319                                 }
 320                         }
 321                 }
 322                 else
 323                 {
 324                         DBG1(DBG_IKE, "CHILD_SA rekey collision lost, "
 325                                  "deleting rekeyed child");
 326                         to_delete = this->child_create->get_child(this->child_create);
 327                 }
 328         }
 329         else
 330         {       /* CHILD_DELETE */
 331                 child_delete_t *del = (child_delete_t*)this->collision;
 332
 333                 /* we didn't had a chance to compare the nonces, so we delete
 334                  * the CHILD_SA the other is not deleting. */
 335                 if (del->get_child(del) != this->child_sa)
 336                 {
 337                         DBG1(DBG_IKE, "CHILD_SA rekey/delete collision, "
 338                                  "deleting rekeyed child");
 339                         to_delete = this->child_sa;
 340                 }
 341                 else
 342                 {
 343                         DBG1(DBG_IKE, "CHILD_SA rekey/delete collision, "
 344                                  "deleting redundant child");
 345                         to_delete = this->child_create->get_child(this->child_create);
 346                 }
 347         }
 348         return to_delete;
 349 }
 350
 351 METHOD(task_t, process_i, status_t,
 352         private_child_rekey_t *this, message_t *message)
 353 {
 354         protocol_id_t protocol;
 355         uint32_t spi;
 356         child_sa_t *to_delete;
 357
 358         if (message->get_notify(message, NO_ADDITIONAL_SAS))
 359         {
 360                 DBG1(DBG_IKE, "peer seems to not support CHILD_SA rekeying, "
 361                          "starting reauthentication");
 362                 this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
 363                 lib->processor->queue_job(lib->processor,
 364                                 (job_t*)rekey_ike_sa_job_create(
 365                                                         this->ike_sa->get_id(this->ike_sa), TRUE));
 366                 return SUCCESS;
 367         }
 368         if (message->get_notify(message, CHILD_SA_NOT_FOUND))
 369         {
 370                 child_cfg_t *child_cfg;
 371                 uint32_t reqid;
 372
 373                 if (this->collision &&
 374                         this->collision->get_type(this->collision) == TASK_CHILD_DELETE)
 375                 {       /* ignore this error if we already deleted the CHILD_SA on the
 376                          * peer's behalf (could happen if the other peer does not detect
 377                          * the collision and did not respond with TEMPORARY_FAILURE) */
 378                         return SUCCESS;
 379                 }
 380                 DBG1(DBG_IKE, "peer didn't find the CHILD_SA we tried to rekey");
 381                 /* FIXME: according to RFC 7296 we should only create a new CHILD_SA if
 382                  * it does not exist yet, we currently have no good way of checking for
 383                  * that (we could go by name, but that might be tricky e.g. due to
 384                  * narrowing) */
 385                 spi = this->child_sa->get_spi(this->child_sa, TRUE);
 386                 reqid = this->child_sa->get_reqid(this->child_sa);
 387                 protocol = this->child_sa->get_protocol(this->child_sa);
 388                 child_cfg = this->child_sa->get_config(this->child_sa);
 389                 child_cfg->get_ref(child_cfg);
 390                 charon->bus->child_updown(charon->bus, this->child_sa, FALSE);
 391                 this->ike_sa->destroy_child_sa(this->ike_sa, protocol, spi);
 392                 return this->ike_sa->initiate(this->ike_sa,
 393                                                                           child_cfg->get_ref(child_cfg), reqid,
 394                                                                           NULL, NULL);
 395         }
 396
 397         if (this->child_create->task.process(&this->child_create->task,
 398                                                                                  message) == NEED_MORE)
 399         {
 400                 /* bad DH group while rekeying, retry, or failure requiring deletion */
 401                 return NEED_MORE;
 402         }
 403         if (message->get_payload(message, PLV2_SECURITY_ASSOCIATION) == NULL)
 404         {
 405                 /* establishing new child failed, reuse old and try again. but not when
 406                  * we received a delete in the meantime */
 407                 if (!this->collision ||
 408                          this->collision->get_type(this->collision) != TASK_CHILD_DELETE)
 409                 {
 410                         schedule_delayed_rekey(this);
 411                 }
 412                 return SUCCESS;
 413         }
 414
 415         /* check for rekey collisions */
 416         if (this->collision)
 417         {
 418                 to_delete = handle_collision(this);
 419         }
 420         else
 421         {
 422                 to_delete = this->child_sa;
 423         }
 424
 425         if (to_delete != this->child_create->get_child(this->child_create))
 426         {       /* invoke rekey hook if rekeying successful */
 427                 charon->bus->child_rekey(charon->bus, this->child_sa,
 428                                                         this->child_create->get_child(this->child_create));
 429         }
 430
 431         if (to_delete == NULL)
 432         {
 433                 return SUCCESS;
 434         }
 435         /* disable updown event for redundant CHILD_SA */
 436         if (to_delete->get_state(to_delete) != CHILD_REKEYED)
 437         {
 438                 to_delete->set_state(to_delete, CHILD_REKEYED);
 439         }
 440         spi = to_delete->get_spi(to_delete, TRUE);
 441         protocol = to_delete->get_protocol(to_delete);
 442
 443         /* rekeying done, delete the obsolete CHILD_SA using a subtask */
 444         this->child_delete = child_delete_create(this->ike_sa, protocol, spi, FALSE);
 445         this->public.task.build = (status_t(*)(task_t*,message_t*))build_i_delete;
 446         this->public.task.process = (status_t(*)(task_t*,message_t*))process_i_delete;
 447
 448         return NEED_MORE;
 449 }
 450
 451 METHOD(task_t, get_type, task_type_t,
 452         private_child_rekey_t *this)
 453 {
 454         return TASK_CHILD_REKEY;
 455 }
 456
 457 METHOD(child_rekey_t, is_redundant, bool,
 458         private_child_rekey_t *this, child_sa_t *child)
 459 {
 460         if (this->collision &&
 461                 this->collision->get_type(this->collision) == TASK_CHILD_REKEY)
 462         {
 463                 private_child_rekey_t *rekey = (private_child_rekey_t*)this->collision;
 464                 return child == rekey->child_create->get_child(rekey->child_create);
 465         }
 466         return FALSE;
 467 }
 468
 469 METHOD(child_rekey_t, collide, void,
 470         private_child_rekey_t *this, task_t *other)
 471 {
 472         /* the task manager only detects exchange collision, but not if
 473          * the collision is for the same child. we check it here. */
 474         if (other->get_type(other) == TASK_CHILD_REKEY)
 475         {
 476                 private_child_rekey_t *rekey = (private_child_rekey_t*)other;
 477                 child_sa_t *other_child;
 478
 479                 if (rekey->child_sa != this->child_sa)
 480                 {       /* not the same child => no collision */
 481                         other->destroy(other);
 482                         return;
 483                 }
 484                 /* ignore passive tasks that did not successfully create a CHILD_SA */
 485                 other_child = rekey->child_create->get_child(rekey->child_create);
 486                 if (!other_child ||
 487                          other_child->get_state(other_child) != CHILD_INSTALLED)
 488                 {
 489                         other->destroy(other);
 490                         return;
 491                 }
 492         }
 493         else if (other->get_type(other) == TASK_CHILD_DELETE)
 494         {
 495                 child_delete_t *del = (child_delete_t*)other;
 496                 if (is_redundant(this, del->get_child(del)))
 497                 {
 498                         this->other_child_destroyed = TRUE;
 499                         other->destroy(other);
 500                         return;
 501                 }
 502                 if (del->get_child(del) != this->child_sa)
 503                 {
 504                         /* not the same child => no collision */
 505                         other->destroy(other);
 506                         return;
 507                 }
 508         }
 509         else
 510         {
 511                 /* any other task is not critical for collisions, ignore */
 512                 other->destroy(other);
 513                 return;
 514         }
 515         DBG1(DBG_IKE, "detected %N collision with %N", task_type_names,
 516                  TASK_CHILD_REKEY, task_type_names, other->get_type(other));
 517         DESTROY_IF(this->collision);
 518         this->collision = other;
 519 }
 520
 521 METHOD(task_t, migrate, void,
 522         private_child_rekey_t *this, ike_sa_t *ike_sa)
 523 {
 524         if (this->child_create)
 525         {
 526                 this->child_create->task.migrate(&this->child_create->task, ike_sa);
 527         }
 528         if (this->child_delete)
 529         {
 530                 this->child_delete->task.migrate(&this->child_delete->task, ike_sa);
 531         }
 532         DESTROY_IF(this->collision);
 533
 534         this->ike_sa = ike_sa;
 535         this->collision = NULL;
 536 }
 537
 538 METHOD(task_t, destroy, void,
 539         private_child_rekey_t *this)
 540 {
 541         if (this->child_create)
 542         {
 543                 this->child_create->task.destroy(&this->child_create->task);
 544         }
 545         if (this->child_delete)
 546         {
 547                 this->child_delete->task.destroy(&this->child_delete->task);
 548         }
 549         DESTROY_IF(this->collision);
 550         free(this);
 551 }
 552
 553 /*
 554  * Described in header.
 555  */
 556 child_rekey_t *child_rekey_create(ike_sa_t *ike_sa, protocol_id_t protocol,
 557                                                                   uint32_t spi)
 558 {
 559         private_child_rekey_t *this;
 560
 561         INIT(this,
 562                 .public = {
 563                         .task = {
 564                                 .get_type = _get_type,
 565                                 .migrate = _migrate,
 566                                 .destroy = _destroy,
 567                         },
 568                         .is_redundant = _is_redundant,
 569                         .collide = _collide,
 570                 },
 571                 .ike_sa = ike_sa,
 572                 .protocol = protocol,
 573                 .spi = spi,
 574         );
 575
 576         if (protocol != PROTO_NONE)
 577         {
 578                 this->public.task.build = _build_i;
 579                 this->public.task.process = _process_i;
 580                 this->initiator = TRUE;
 581                 this->child_create = NULL;
 582         }
 583         else
 584         {
 585                 this->public.task.build = _build_r;
 586                 this->public.task.process = _process_r;
 587                 this->initiator = FALSE;
 588                 this->child_create = child_create_create(ike_sa, NULL, TRUE, NULL, NULL);
 589         }
 590
 591         return &this->public;
 592 }