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  * Implementation of task_t.build for initiator, after rekeying
  91  */
  92 static status_t build_i_delete(private_child_rekey_t *this, message_t *message)
  93 {
  94         /* update exchange type to INFORMATIONAL for the delete */
  95         message->set_exchange_type(message, INFORMATIONAL);
  96
  97         return this->child_delete->task.build(&this->child_delete->task, message);
  98 }
  99
 100 /**
 101  * Implementation of task_t.process for initiator, after rekeying
 102  */
 103 static status_t process_i_delete(private_child_rekey_t *this, message_t *message)
 104 {
 105         return this->child_delete->task.process(&this->child_delete->task, message);
 106 }
 107
 108 /**
 109  * find a child using the REKEY_SA notify
 110  */
 111 static void find_child(private_child_rekey_t *this, message_t *message)
 112 {
 113         notify_payload_t *notify;
 114         protocol_id_t protocol;
 115         u_int32_t spi;
 116
 117         notify = message->get_notify(message, REKEY_SA);
 118         if (notify)
 119         {
 120                 protocol = notify->get_protocol_id(notify);
 121                 spi = notify->get_spi(notify);
 122
 123                 if (protocol == PROTO_ESP || protocol == PROTO_AH)
 124                 {
 125                         this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, protocol,
 126                                                                                                                 spi, FALSE);
 127                 }
 128         }
 129 }
 130
 131 METHOD(task_t, build_i, status_t,
 132         private_child_rekey_t *this, message_t *message)
 133 {
 134         notify_payload_t *notify;
 135         u_int32_t reqid;
 136         child_cfg_t *config;
 137
 138         this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, this->protocol,
 139                                                                                                 this->spi, TRUE);
 140         if (!this->child_sa)
 141         {       /* check if it is an outbound CHILD_SA */
 142                 this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, this->protocol,
 143                                                                                                         this->spi, FALSE);
 144                 if (!this->child_sa)
 145                 {       /* CHILD_SA is gone, unable to rekey. As an empty CREATE_CHILD_SA
 146                          * exchange is invalid, we fall back to an INFORMATIONAL exchange.*/
 147                         message->set_exchange_type(message, INFORMATIONAL);
 148                         return SUCCESS;
 149                 }
 150                 /* we work only with the inbound SPI */
 151                 this->spi = this->child_sa->get_spi(this->child_sa, TRUE);
 152         }
 153         config = this->child_sa->get_config(this->child_sa);
 154
 155         /* we just need the rekey notify ... */
 156         notify = notify_payload_create_from_protocol_and_type(NOTIFY,
 157                                                                                                         this->protocol, REKEY_SA);
 158         notify->set_spi(notify, this->spi);
 159         message->add_payload(message, (payload_t*)notify);
 160
 161         /* ... our CHILD_CREATE task does the hard work for us. */
 162         if (!this->child_create)
 163         {
 164                 this->child_create = child_create_create(this->ike_sa, config, TRUE,
 165                                                                                                  NULL, NULL);
 166         }
 167         reqid = this->child_sa->get_reqid(this->child_sa);
 168         this->child_create->use_reqid(this->child_create, reqid);
 169         this->child_create->task.build(&this->child_create->task, message);
 170
 171         this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
 172
 173         return NEED_MORE;
 174 }
 175
 176 METHOD(task_t, process_r, status_t,
 177         private_child_rekey_t *this, message_t *message)
 178 {
 179         /* let the CHILD_CREATE task process the message */
 180         this->child_create->task.process(&this->child_create->task, message);
 181
 182         find_child(this, message);
 183
 184         return NEED_MORE;
 185 }
 186
 187 METHOD(task_t, build_r, status_t,
 188         private_child_rekey_t *this, message_t *message)
 189 {
 190         u_int32_t reqid;
 191
 192         if (this->child_sa == NULL ||
 193                 this->child_sa->get_state(this->child_sa) == CHILD_DELETING)
 194         {
 195                 DBG1(DBG_IKE, "unable to rekey, CHILD_SA not found");
 196                 message->add_notify(message, TRUE, NO_PROPOSAL_CHOSEN, chunk_empty);
 197                 return SUCCESS;
 198         }
 199
 200         /* let the CHILD_CREATE task build the response */
 201         reqid = this->child_sa->get_reqid(this->child_sa);
 202         this->child_create->use_reqid(this->child_create, reqid);
 203         this->child_create->task.build(&this->child_create->task, message);
 204
 205         if (message->get_payload(message, SECURITY_ASSOCIATION) == NULL)
 206         {
 207                 /* rekeying failed, reuse old child */
 208                 this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
 209                 return SUCCESS;
 210         }
 211
 212         this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
 213
 214         /* invoke rekey hook */
 215         charon->bus->child_rekey(charon->bus, this->child_sa,
 216                                                          this->child_create->get_child(this->child_create));
 217         return SUCCESS;
 218 }
 219
 220 /**
 221  * Handle a rekey collision
 222  */
 223 static child_sa_t *handle_collision(private_child_rekey_t *this)
 224 {
 225         child_sa_t *to_delete;
 226
 227         if (this->collision->get_type(this->collision) == TASK_CHILD_REKEY)
 228         {
 229                 chunk_t this_nonce, other_nonce;
 230                 private_child_rekey_t *other = (private_child_rekey_t*)this->collision;
 231
 232                 this_nonce = this->child_create->get_lower_nonce(this->child_create);
 233                 other_nonce = other->child_create->get_lower_nonce(other->child_create);
 234
 235                 /* if we have the lower nonce, delete rekeyed SA. If not, delete
 236                  * the redundant. */
 237                 if (memcmp(this_nonce.ptr, other_nonce.ptr,
 238                                    min(this_nonce.len, other_nonce.len)) > 0)
 239                 {
 240                         child_sa_t *child_sa;
 241
 242                         DBG1(DBG_IKE, "CHILD_SA rekey collision won, deleting old child");
 243                         to_delete = this->child_sa;
 244                         /* don't touch child other created, it has already been deleted */
 245                         if (!this->other_child_destroyed)
 246                         {
 247                                 /* disable close action for the redundand child */
 248                                 child_sa = other->child_create->get_child(other->child_create);
 249                                 if (child_sa)
 250                                 {
 251                                         child_sa->set_close_action(child_sa, ACTION_NONE);
 252                                 }
 253                         }
 254                 }
 255                 else
 256                 {
 257                         DBG1(DBG_IKE, "CHILD_SA rekey collision lost, "
 258                                  "deleting rekeyed child");
 259                         to_delete = this->child_create->get_child(this->child_create);
 260                 }
 261         }
 262         else
 263         {       /* CHILD_DELETE */
 264                 child_delete_t *del = (child_delete_t*)this->collision;
 265
 266                 /* we didn't had a chance to compare the nonces, so we delete
 267                  * the CHILD_SA the other is not deleting. */
 268                 if (del->get_child(del) != this->child_sa)
 269                 {
 270                         DBG1(DBG_IKE, "CHILD_SA rekey/delete collision, "
 271                                  "deleting rekeyed child");
 272                         to_delete = this->child_sa;
 273                 }
 274                 else
 275                 {
 276                         DBG1(DBG_IKE, "CHILD_SA rekey/delete collision, "
 277                                  "deleting redundant child");
 278                         to_delete = this->child_create->get_child(this->child_create);
 279                 }
 280         }
 281         return to_delete;
 282 }
 283
 284 METHOD(task_t, process_i, status_t,
 285         private_child_rekey_t *this, message_t *message)
 286 {
 287         protocol_id_t protocol;
 288         u_int32_t spi;
 289         child_sa_t *to_delete;
 290
 291         if (message->get_notify(message, NO_ADDITIONAL_SAS))
 292         {
 293                 DBG1(DBG_IKE, "peer seems to not support CHILD_SA rekeying, "
 294                          "starting reauthentication");
 295                 this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
 296                 lib->processor->queue_job(lib->processor,
 297                                 (job_t*)rekey_ike_sa_job_create(
 298                                                         this->ike_sa->get_id(this->ike_sa), TRUE));
 299                 return SUCCESS;
 300         }
 301
 302         if (this->child_create->task.process(&this->child_create->task,
 303                                                                                  message) == NEED_MORE)
 304         {
 305                 /* bad DH group while rekeying, try again */
 306                 this->child_create->task.migrate(&this->child_create->task, this->ike_sa);
 307                 return NEED_MORE;
 308         }
 309         if (message->get_payload(message, SECURITY_ASSOCIATION) == NULL)
 310         {
 311                 /* establishing new child failed, reuse old. but not when we
 312                  * received a delete in the meantime */
 313                 if (!(this->collision &&
 314                           this->collision->get_type(this->collision) == TASK_CHILD_DELETE))
 315                 {
 316                         job_t *job;
 317                         u_int32_t retry = RETRY_INTERVAL - (random() % RETRY_JITTER);
 318
 319                         job = (job_t*)rekey_child_sa_job_create(
 320                                                                 this->child_sa->get_reqid(this->child_sa),
 321                                                                 this->child_sa->get_protocol(this->child_sa),
 322                                                                 this->child_sa->get_spi(this->child_sa, TRUE));
 323                         DBG1(DBG_IKE, "CHILD_SA rekeying failed, "
 324                                                                 "trying again in %d seconds", retry);
 325                         this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
 326                         lib->scheduler->schedule_job(lib->scheduler, job, retry);
 327                 }
 328                 return SUCCESS;
 329         }
 330
 331         /* check for rekey collisions */
 332         if (this->collision)
 333         {
 334                 to_delete = handle_collision(this);
 335         }
 336         else
 337         {
 338                 to_delete = this->child_sa;
 339         }
 340
 341         if (to_delete != this->child_create->get_child(this->child_create))
 342         {       /* invoke rekey hook if rekeying successful */
 343                 charon->bus->child_rekey(charon->bus, this->child_sa,
 344                                                         this->child_create->get_child(this->child_create));
 345         }
 346
 347         if (to_delete == NULL)
 348         {
 349                 return SUCCESS;
 350         }
 351         spi = to_delete->get_spi(to_delete, TRUE);
 352         protocol = to_delete->get_protocol(to_delete);
 353
 354         /* rekeying done, delete the obsolete CHILD_SA using a subtask */
 355         this->child_delete = child_delete_create(this->ike_sa, protocol, spi);
 356         this->public.task.build = (status_t(*)(task_t*,message_t*))build_i_delete;
 357         this->public.task.process = (status_t(*)(task_t*,message_t*))process_i_delete;
 358
 359         return NEED_MORE;
 360 }
 361
 362 METHOD(task_t, get_type, task_type_t,
 363         private_child_rekey_t *this)
 364 {
 365         return TASK_CHILD_REKEY;
 366 }
 367
 368 METHOD(child_rekey_t, collide, void,
 369         private_child_rekey_t *this, task_t *other)
 370 {
 371         /* the task manager only detects exchange collision, but not if
 372          * the collision is for the same child. we check it here. */
 373         if (other->get_type(other) == TASK_CHILD_REKEY)
 374         {
 375                 private_child_rekey_t *rekey = (private_child_rekey_t*)other;
 376                 if (rekey->child_sa != this->child_sa)
 377                 {
 378                         /* not the same child => no collision */
 379                         other->destroy(other);
 380                         return;
 381                 }
 382         }
 383         else if (other->get_type(other) == TASK_CHILD_DELETE)
 384         {
 385                 child_delete_t *del = (child_delete_t*)other;
 386                 if (del->get_child(del) == this->child_create->get_child(this->child_create))
 387                 {
 388                         /* peer deletes redundant child created in collision */
 389                         this->other_child_destroyed = TRUE;
 390                         other->destroy(other);
 391                         return;
 392                 }
 393                 if (del->get_child(del) != this->child_sa)
 394                 {
 395                         /* not the same child => no collision */
 396                         other->destroy(other);
 397                         return;
 398                 }
 399         }
 400         else
 401         {
 402                 /* any other task is not critical for collisisions, ignore */
 403                 other->destroy(other);
 404                 return;
 405         }
 406         DBG1(DBG_IKE, "detected %N collision with %N", task_type_names,
 407                  TASK_CHILD_REKEY, task_type_names, other->get_type(other));
 408         DESTROY_IF(this->collision);
 409         this->collision = other;
 410 }
 411
 412 METHOD(task_t, migrate, void,
 413         private_child_rekey_t *this, ike_sa_t *ike_sa)
 414 {
 415         if (this->child_create)
 416         {
 417                 this->child_create->task.migrate(&this->child_create->task, ike_sa);
 418         }
 419         if (this->child_delete)
 420         {
 421                 this->child_delete->task.migrate(&this->child_delete->task, ike_sa);
 422         }
 423         DESTROY_IF(this->collision);
 424
 425         this->ike_sa = ike_sa;
 426         this->collision = NULL;
 427 }
 428
 429 METHOD(task_t, destroy, void,
 430         private_child_rekey_t *this)
 431 {
 432         if (this->child_create)
 433         {
 434                 this->child_create->task.destroy(&this->child_create->task);
 435         }
 436         if (this->child_delete)
 437         {
 438                 this->child_delete->task.destroy(&this->child_delete->task);
 439         }
 440         DESTROY_IF(this->collision);
 441         free(this);
 442 }
 443
 444 /*
 445  * Described in header.
 446  */
 447 child_rekey_t *child_rekey_create(ike_sa_t *ike_sa, protocol_id_t protocol,
 448                                                                   u_int32_t spi)
 449 {
 450         private_child_rekey_t *this;
 451
 452         INIT(this,
 453                 .public = {
 454                         .task = {
 455                                 .get_type = _get_type,
 456                                 .migrate = _migrate,
 457                                 .destroy = _destroy,
 458                         },
 459                         .collide = _collide,
 460                 },
 461                 .ike_sa = ike_sa,
 462                 .protocol = protocol,
 463                 .spi = spi,
 464         );
 465
 466         if (protocol != PROTO_NONE)
 467         {
 468                 this->public.task.build = _build_i;
 469                 this->public.task.process = _process_i;
 470                 this->initiator = TRUE;
 471                 this->child_create = NULL;
 472         }
 473         else
 474         {
 475                 this->public.task.build = _build_r;
 476                 this->public.task.process = _process_r;
 477                 this->initiator = FALSE;
 478                 this->child_create = child_create_create(ike_sa, NULL, TRUE, NULL, NULL);
 479         }
 480
 481         return &this->public;
 482 }