child-rekey: Don't install outbound SA in case of lost collisions
[strongswan.git] / 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 child_sa_t **to_install)
288 {
289 child_sa_t *to_delete;
290
291 if (this->collision->get_type(this->collision) == TASK_CHILD_REKEY)
292 {
293 chunk_t this_nonce, other_nonce;
294 private_child_rekey_t *other = (private_child_rekey_t*)this->collision;
295
296 this_nonce = this->child_create->get_lower_nonce(this->child_create);
297 other_nonce = other->child_create->get_lower_nonce(other->child_create);
298
299 /* if we have the lower nonce, delete rekeyed SA. If not, delete
300 * the redundant. */
301 if (memcmp(this_nonce.ptr, other_nonce.ptr,
302 min(this_nonce.len, other_nonce.len)) > 0)
303 {
304 child_sa_t *child_sa;
305
306 DBG1(DBG_IKE, "CHILD_SA rekey collision won, deleting old child");
307 *to_install = this->child_create->get_child(this->child_create);
308 to_delete = this->child_sa;
309 /* don't touch child other created, it has already been deleted */
310 if (!this->other_child_destroyed)
311 {
312 /* disable close action and updown event for redundant child */
313 child_sa = other->child_create->get_child(other->child_create);
314 if (child_sa)
315 {
316 child_sa->set_close_action(child_sa, ACTION_NONE);
317 if (child_sa->get_state(child_sa) != CHILD_REKEYED)
318 {
319 child_sa->set_state(child_sa, CHILD_REKEYED);
320 }
321 }
322 }
323 }
324 else
325 {
326 DBG1(DBG_IKE, "CHILD_SA rekey collision lost, "
327 "deleting rekeyed child");
328 to_delete = this->child_create->get_child(this->child_create);
329 }
330 }
331 else
332 { /* CHILD_DELETE */
333 child_delete_t *del = (child_delete_t*)this->collision;
334
335 /* we didn't had a chance to compare the nonces, so we delete
336 * the CHILD_SA the other is not deleting. */
337 if (del->get_child(del) != this->child_sa)
338 {
339 DBG1(DBG_IKE, "CHILD_SA rekey/delete collision, "
340 "deleting rekeyed child");
341 to_delete = this->child_sa;
342 }
343 else
344 {
345 DBG1(DBG_IKE, "CHILD_SA rekey/delete collision, "
346 "deleting redundant child");
347 to_delete = this->child_create->get_child(this->child_create);
348 }
349 }
350 return to_delete;
351 }
352
353 METHOD(task_t, process_i, status_t,
354 private_child_rekey_t *this, message_t *message)
355 {
356 protocol_id_t protocol;
357 uint32_t spi;
358 child_sa_t *to_delete, *to_install = NULL;
359
360 if (message->get_notify(message, NO_ADDITIONAL_SAS))
361 {
362 DBG1(DBG_IKE, "peer seems to not support CHILD_SA rekeying, "
363 "starting reauthentication");
364 this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
365 lib->processor->queue_job(lib->processor,
366 (job_t*)rekey_ike_sa_job_create(
367 this->ike_sa->get_id(this->ike_sa), TRUE));
368 return SUCCESS;
369 }
370 if (message->get_notify(message, CHILD_SA_NOT_FOUND))
371 {
372 child_cfg_t *child_cfg;
373 uint32_t reqid;
374
375 if (this->collision &&
376 this->collision->get_type(this->collision) == TASK_CHILD_DELETE)
377 { /* ignore this error if we already deleted the CHILD_SA on the
378 * peer's behalf (could happen if the other peer does not detect
379 * the collision and did not respond with TEMPORARY_FAILURE) */
380 return SUCCESS;
381 }
382 DBG1(DBG_IKE, "peer didn't find the CHILD_SA we tried to rekey");
383 /* FIXME: according to RFC 7296 we should only create a new CHILD_SA if
384 * it does not exist yet, we currently have no good way of checking for
385 * that (we could go by name, but that might be tricky e.g. due to
386 * narrowing) */
387 spi = this->child_sa->get_spi(this->child_sa, TRUE);
388 reqid = this->child_sa->get_reqid(this->child_sa);
389 protocol = this->child_sa->get_protocol(this->child_sa);
390 child_cfg = this->child_sa->get_config(this->child_sa);
391 child_cfg->get_ref(child_cfg);
392 charon->bus->child_updown(charon->bus, this->child_sa, FALSE);
393 this->ike_sa->destroy_child_sa(this->ike_sa, protocol, spi);
394 return this->ike_sa->initiate(this->ike_sa,
395 child_cfg->get_ref(child_cfg), reqid,
396 NULL, NULL);
397 }
398
399 if (this->child_create->task.process(&this->child_create->task,
400 message) == NEED_MORE)
401 {
402 /* bad DH group while rekeying, retry, or failure requiring deletion */
403 return NEED_MORE;
404 }
405 if (message->get_payload(message, PLV2_SECURITY_ASSOCIATION) == NULL)
406 {
407 /* establishing new child failed, reuse old and try again. but not when
408 * we received a delete in the meantime */
409 if (!this->collision ||
410 this->collision->get_type(this->collision) != TASK_CHILD_DELETE)
411 {
412 schedule_delayed_rekey(this);
413 }
414 return SUCCESS;
415 }
416
417 /* check for rekey collisions */
418 if (this->collision)
419 {
420 to_delete = handle_collision(this, &to_install);
421 }
422 else
423 {
424 to_install = this->child_create->get_child(this->child_create);
425 to_delete = this->child_sa;
426 }
427 if (to_install)
428 {
429 if (to_install->install_outbound(to_install) != SUCCESS)
430 {
431 DBG1(DBG_IKE, "unable to install outbound IPsec SA (SAD) in kernel");
432 charon->bus->alert(charon->bus, ALERT_INSTALL_CHILD_SA_FAILED,
433 to_install);
434 /* FIXME: delete the child_sa? fail the task? */
435 }
436 else
437 {
438 linked_list_t *my_ts, *other_ts;
439
440 my_ts = linked_list_create_from_enumerator(
441 to_install->create_ts_enumerator(to_install, TRUE));
442 other_ts = linked_list_create_from_enumerator(
443 to_install->create_ts_enumerator(to_install, FALSE));
444
445 DBG0(DBG_IKE, "outbound CHILD_SA %s{%d} established "
446 "with SPIs %.8x_i %.8x_o and TS %#R === %#R",
447 to_install->get_name(to_install),
448 to_install->get_unique_id(to_install),
449 ntohl(to_install->get_spi(to_install, TRUE)),
450 ntohl(to_install->get_spi(to_install, FALSE)),
451 my_ts, other_ts);
452
453 my_ts->destroy(my_ts);
454 other_ts->destroy(other_ts);
455 }
456 }
457 if (to_delete != this->child_create->get_child(this->child_create))
458 { /* invoke rekey hook if rekeying successful */
459 charon->bus->child_rekey(charon->bus, this->child_sa,
460 this->child_create->get_child(this->child_create));
461 }
462 if (to_delete == NULL)
463 {
464 return SUCCESS;
465 }
466 /* disable updown event for redundant CHILD_SA */
467 if (to_delete->get_state(to_delete) != CHILD_REKEYED)
468 {
469 to_delete->set_state(to_delete, CHILD_REKEYED);
470 }
471 spi = to_delete->get_spi(to_delete, TRUE);
472 protocol = to_delete->get_protocol(to_delete);
473
474 /* rekeying done, delete the obsolete CHILD_SA using a subtask */
475 this->child_delete = child_delete_create(this->ike_sa, protocol, spi, FALSE);
476 this->public.task.build = (status_t(*)(task_t*,message_t*))build_i_delete;
477 this->public.task.process = (status_t(*)(task_t*,message_t*))process_i_delete;
478
479 return NEED_MORE;
480 }
481
482 METHOD(task_t, get_type, task_type_t,
483 private_child_rekey_t *this)
484 {
485 return TASK_CHILD_REKEY;
486 }
487
488 METHOD(child_rekey_t, is_redundant, bool,
489 private_child_rekey_t *this, child_sa_t *child)
490 {
491 if (this->collision &&
492 this->collision->get_type(this->collision) == TASK_CHILD_REKEY)
493 {
494 private_child_rekey_t *rekey = (private_child_rekey_t*)this->collision;
495 return child == rekey->child_create->get_child(rekey->child_create);
496 }
497 return FALSE;
498 }
499
500 METHOD(child_rekey_t, collide, void,
501 private_child_rekey_t *this, task_t *other)
502 {
503 /* the task manager only detects exchange collision, but not if
504 * the collision is for the same child. we check it here. */
505 if (other->get_type(other) == TASK_CHILD_REKEY)
506 {
507 private_child_rekey_t *rekey = (private_child_rekey_t*)other;
508 child_sa_t *other_child;
509
510 if (rekey->child_sa != this->child_sa)
511 { /* not the same child => no collision */
512 other->destroy(other);
513 return;
514 }
515 /* ignore passive tasks that did not successfully create a CHILD_SA */
516 other_child = rekey->child_create->get_child(rekey->child_create);
517 if (!other_child ||
518 other_child->get_state(other_child) != CHILD_INSTALLED)
519 {
520 other->destroy(other);
521 return;
522 }
523 }
524 else if (other->get_type(other) == TASK_CHILD_DELETE)
525 {
526 child_delete_t *del = (child_delete_t*)other;
527 if (is_redundant(this, del->get_child(del)))
528 {
529 this->other_child_destroyed = TRUE;
530 other->destroy(other);
531 return;
532 }
533 if (del->get_child(del) != this->child_sa)
534 {
535 /* not the same child => no collision */
536 other->destroy(other);
537 return;
538 }
539 }
540 else
541 {
542 /* any other task is not critical for collisions, ignore */
543 other->destroy(other);
544 return;
545 }
546 DBG1(DBG_IKE, "detected %N collision with %N", task_type_names,
547 TASK_CHILD_REKEY, task_type_names, other->get_type(other));
548 DESTROY_IF(this->collision);
549 this->collision = other;
550 }
551
552 METHOD(task_t, migrate, void,
553 private_child_rekey_t *this, ike_sa_t *ike_sa)
554 {
555 if (this->child_create)
556 {
557 this->child_create->task.migrate(&this->child_create->task, ike_sa);
558 }
559 if (this->child_delete)
560 {
561 this->child_delete->task.migrate(&this->child_delete->task, ike_sa);
562 }
563 DESTROY_IF(this->collision);
564
565 this->ike_sa = ike_sa;
566 this->collision = NULL;
567 }
568
569 METHOD(task_t, destroy, void,
570 private_child_rekey_t *this)
571 {
572 if (this->child_create)
573 {
574 this->child_create->task.destroy(&this->child_create->task);
575 }
576 if (this->child_delete)
577 {
578 this->child_delete->task.destroy(&this->child_delete->task);
579 }
580 DESTROY_IF(this->collision);
581 free(this);
582 }
583
584 /*
585 * Described in header.
586 */
587 child_rekey_t *child_rekey_create(ike_sa_t *ike_sa, protocol_id_t protocol,
588 uint32_t spi)
589 {
590 private_child_rekey_t *this;
591
592 INIT(this,
593 .public = {
594 .task = {
595 .get_type = _get_type,
596 .migrate = _migrate,
597 .destroy = _destroy,
598 },
599 .is_redundant = _is_redundant,
600 .collide = _collide,
601 },
602 .ike_sa = ike_sa,
603 .protocol = protocol,
604 .spi = spi,
605 );
606
607 if (protocol != PROTO_NONE)
608 {
609 this->public.task.build = _build_i;
610 this->public.task.process = _process_i;
611 this->initiator = TRUE;
612 this->child_create = NULL;
613 }
614 else
615 {
616 this->public.task.build = _build_r;
617 this->public.task.process = _process_r;
618 this->initiator = FALSE;
619 this->child_create = child_create_create(ike_sa, NULL, TRUE, NULL, NULL);
620 }
621
622 return &this->public;
623 }