Merge branch 'exchange-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
136 notify = message->get_notify(message, REKEY_SA);
137 if (notify)
138 {
139 protocol = notify->get_protocol_id(notify);
140 spi = notify->get_spi(notify);
141
142 if (protocol == PROTO_ESP || protocol == PROTO_AH)
143 {
144 this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, protocol,
145 spi, FALSE);
146 }
147 }
148 }
149
150 METHOD(task_t, build_i, status_t,
151 private_child_rekey_t *this, message_t *message)
152 {
153 notify_payload_t *notify;
154 uint32_t reqid;
155 child_cfg_t *config;
156
157 this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, this->protocol,
158 this->spi, TRUE);
159 if (!this->child_sa)
160 { /* check if it is an outbound CHILD_SA */
161 this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, this->protocol,
162 this->spi, FALSE);
163 if (this->child_sa)
164 {
165 /* we work only with the inbound SPI */
166 this->spi = this->child_sa->get_spi(this->child_sa, TRUE);
167 }
168 }
169 if (!this->child_sa ||
170 (!this->child_create &&
171 this->child_sa->get_state(this->child_sa) != CHILD_INSTALLED) ||
172 (this->child_create &&
173 this->child_sa->get_state(this->child_sa) != CHILD_REKEYING))
174 {
175 /* CHILD_SA is gone or in the wrong state, unable to rekey */
176 message->set_exchange_type(message, EXCHANGE_TYPE_UNDEFINED);
177 return SUCCESS;
178 }
179 config = this->child_sa->get_config(this->child_sa);
180
181
182 /* our CHILD_CREATE task does the hard work for us */
183 if (!this->child_create)
184 {
185 this->child_create = child_create_create(this->ike_sa,
186 config->get_ref(config), TRUE, NULL, NULL);
187 }
188 reqid = this->child_sa->get_reqid(this->child_sa);
189 this->child_create->use_reqid(this->child_create, reqid);
190 this->child_create->use_marks(this->child_create,
191 this->child_sa->get_mark(this->child_sa, TRUE).value,
192 this->child_sa->get_mark(this->child_sa, FALSE).value);
193
194 if (this->child_create->task.build(&this->child_create->task,
195 message) != NEED_MORE)
196 {
197 schedule_delayed_rekey(this);
198 return FAILED;
199 }
200 if (message->get_exchange_type(message) == CREATE_CHILD_SA)
201 {
202 /* don't add the notify if the CHILD_CREATE task changed the exchange */
203 notify = notify_payload_create_from_protocol_and_type(PLV2_NOTIFY,
204 this->protocol, REKEY_SA);
205 notify->set_spi(notify, this->spi);
206 message->add_payload(message, (payload_t*)notify);
207 }
208 this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
209
210 return NEED_MORE;
211 }
212
213 METHOD(task_t, process_r, status_t,
214 private_child_rekey_t *this, message_t *message)
215 {
216 /* let the CHILD_CREATE task process the message */
217 this->child_create->task.process(&this->child_create->task, message);
218
219 find_child(this, message);
220
221 return NEED_MORE;
222 }
223
224 METHOD(task_t, build_r, status_t,
225 private_child_rekey_t *this, message_t *message)
226 {
227 child_cfg_t *config;
228 uint32_t reqid;
229 child_sa_state_t state;
230
231 if (!this->child_sa)
232 {
233 DBG1(DBG_IKE, "unable to rekey, CHILD_SA not found");
234 message->add_notify(message, TRUE, CHILD_SA_NOT_FOUND, chunk_empty);
235 return SUCCESS;
236 }
237 if (this->child_sa->get_state(this->child_sa) == CHILD_DELETING)
238 {
239 DBG1(DBG_IKE, "unable to rekey, we are deleting the CHILD_SA");
240 message->add_notify(message, TRUE, TEMPORARY_FAILURE, chunk_empty);
241 return SUCCESS;
242 }
243
244 /* let the CHILD_CREATE task build the response */
245 reqid = this->child_sa->get_reqid(this->child_sa);
246 this->child_create->use_reqid(this->child_create, reqid);
247 this->child_create->use_marks(this->child_create,
248 this->child_sa->get_mark(this->child_sa, TRUE).value,
249 this->child_sa->get_mark(this->child_sa, FALSE).value);
250 config = this->child_sa->get_config(this->child_sa);
251 this->child_create->set_config(this->child_create, config->get_ref(config));
252 this->child_create->task.build(&this->child_create->task, message);
253
254 state = this->child_sa->get_state(this->child_sa);
255 this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
256
257 if (message->get_payload(message, PLV2_SECURITY_ASSOCIATION) == NULL)
258 { /* rekeying failed, reuse old child */
259 this->child_sa->set_state(this->child_sa, state);
260 return SUCCESS;
261 }
262
263 this->child_sa->set_state(this->child_sa, CHILD_REKEYED);
264
265 /* invoke rekey hook */
266 charon->bus->child_rekey(charon->bus, this->child_sa,
267 this->child_create->get_child(this->child_create));
268 return SUCCESS;
269 }
270
271 /**
272 * Handle a rekey collision
273 */
274 static child_sa_t *handle_collision(private_child_rekey_t *this)
275 {
276 child_sa_t *to_delete;
277
278 if (this->collision->get_type(this->collision) == TASK_CHILD_REKEY)
279 {
280 chunk_t this_nonce, other_nonce;
281 private_child_rekey_t *other = (private_child_rekey_t*)this->collision;
282
283 this_nonce = this->child_create->get_lower_nonce(this->child_create);
284 other_nonce = other->child_create->get_lower_nonce(other->child_create);
285
286 /* if we have the lower nonce, delete rekeyed SA. If not, delete
287 * the redundant. */
288 if (memcmp(this_nonce.ptr, other_nonce.ptr,
289 min(this_nonce.len, other_nonce.len)) > 0)
290 {
291 child_sa_t *child_sa;
292
293 DBG1(DBG_IKE, "CHILD_SA rekey collision won, deleting old child");
294 to_delete = this->child_sa;
295 /* don't touch child other created, it has already been deleted */
296 if (!this->other_child_destroyed)
297 {
298 /* disable close action and updown event for redundant child */
299 child_sa = other->child_create->get_child(other->child_create);
300 if (child_sa)
301 {
302 child_sa->set_close_action(child_sa, ACTION_NONE);
303 if (child_sa->get_state(child_sa) != CHILD_REKEYED)
304 {
305 child_sa->set_state(child_sa, CHILD_REKEYED);
306 }
307 }
308 }
309 }
310 else
311 {
312 DBG1(DBG_IKE, "CHILD_SA rekey collision lost, "
313 "deleting rekeyed child");
314 to_delete = this->child_create->get_child(this->child_create);
315 }
316 }
317 else
318 { /* CHILD_DELETE */
319 child_delete_t *del = (child_delete_t*)this->collision;
320
321 /* we didn't had a chance to compare the nonces, so we delete
322 * the CHILD_SA the other is not deleting. */
323 if (del->get_child(del) != this->child_sa)
324 {
325 DBG1(DBG_IKE, "CHILD_SA rekey/delete collision, "
326 "deleting rekeyed child");
327 to_delete = this->child_sa;
328 }
329 else
330 {
331 DBG1(DBG_IKE, "CHILD_SA rekey/delete collision, "
332 "deleting redundant child");
333 to_delete = this->child_create->get_child(this->child_create);
334 }
335 }
336 return to_delete;
337 }
338
339 METHOD(task_t, process_i, status_t,
340 private_child_rekey_t *this, message_t *message)
341 {
342 protocol_id_t protocol;
343 uint32_t spi;
344 child_sa_t *to_delete;
345
346 if (message->get_notify(message, NO_ADDITIONAL_SAS))
347 {
348 DBG1(DBG_IKE, "peer seems to not support CHILD_SA rekeying, "
349 "starting reauthentication");
350 this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
351 lib->processor->queue_job(lib->processor,
352 (job_t*)rekey_ike_sa_job_create(
353 this->ike_sa->get_id(this->ike_sa), TRUE));
354 return SUCCESS;
355 }
356 if (message->get_notify(message, CHILD_SA_NOT_FOUND))
357 {
358 child_cfg_t *child_cfg;
359 uint32_t reqid;
360
361 if (this->collision &&
362 this->collision->get_type(this->collision) == TASK_CHILD_DELETE)
363 { /* ignore this error if we already deleted the CHILD_SA on the
364 * peer's behalf (could happen if the other peer does not detect
365 * the collision and did not respond with TEMPORARY_FAILURE) */
366 return SUCCESS;
367 }
368 DBG1(DBG_IKE, "peer didn't find the CHILD_SA we tried to rekey");
369 /* FIXME: according to RFC 7296 we should only create a new CHILD_SA if
370 * it does not exist yet, we currently have no good way of checking for
371 * that (we could go by name, but that might be tricky e.g. due to
372 * narrowing) */
373 spi = this->child_sa->get_spi(this->child_sa, TRUE);
374 reqid = this->child_sa->get_reqid(this->child_sa);
375 protocol = this->child_sa->get_protocol(this->child_sa);
376 child_cfg = this->child_sa->get_config(this->child_sa);
377 child_cfg->get_ref(child_cfg);
378 charon->bus->child_updown(charon->bus, this->child_sa, FALSE);
379 this->ike_sa->destroy_child_sa(this->ike_sa, protocol, spi);
380 return this->ike_sa->initiate(this->ike_sa,
381 child_cfg->get_ref(child_cfg), reqid,
382 NULL, NULL);
383 }
384
385 if (this->child_create->task.process(&this->child_create->task,
386 message) == NEED_MORE)
387 {
388 /* bad DH group while rekeying, retry, or failure requiring deletion */
389 return NEED_MORE;
390 }
391 if (message->get_payload(message, PLV2_SECURITY_ASSOCIATION) == NULL)
392 {
393 /* establishing new child failed, reuse old and try again. but not when
394 * we received a delete in the meantime */
395 if (!this->collision ||
396 this->collision->get_type(this->collision) != TASK_CHILD_DELETE)
397 {
398 schedule_delayed_rekey(this);
399 }
400 return SUCCESS;
401 }
402
403 /* check for rekey collisions */
404 if (this->collision)
405 {
406 to_delete = handle_collision(this);
407 }
408 else
409 {
410 to_delete = this->child_sa;
411 }
412
413 if (to_delete != this->child_create->get_child(this->child_create))
414 { /* invoke rekey hook if rekeying successful */
415 charon->bus->child_rekey(charon->bus, this->child_sa,
416 this->child_create->get_child(this->child_create));
417 }
418
419 if (to_delete == NULL)
420 {
421 return SUCCESS;
422 }
423 /* disable updown event for redundant CHILD_SA */
424 if (to_delete->get_state(to_delete) != CHILD_REKEYED)
425 {
426 to_delete->set_state(to_delete, CHILD_REKEYED);
427 }
428 spi = to_delete->get_spi(to_delete, TRUE);
429 protocol = to_delete->get_protocol(to_delete);
430
431 /* rekeying done, delete the obsolete CHILD_SA using a subtask */
432 this->child_delete = child_delete_create(this->ike_sa, protocol, spi, FALSE);
433 this->public.task.build = (status_t(*)(task_t*,message_t*))build_i_delete;
434 this->public.task.process = (status_t(*)(task_t*,message_t*))process_i_delete;
435
436 return NEED_MORE;
437 }
438
439 METHOD(task_t, get_type, task_type_t,
440 private_child_rekey_t *this)
441 {
442 return TASK_CHILD_REKEY;
443 }
444
445 METHOD(child_rekey_t, is_redundant, bool,
446 private_child_rekey_t *this, child_sa_t *child)
447 {
448 if (this->collision &&
449 this->collision->get_type(this->collision) == TASK_CHILD_REKEY)
450 {
451 private_child_rekey_t *rekey = (private_child_rekey_t*)this->collision;
452 return child == rekey->child_create->get_child(rekey->child_create);
453 }
454 return FALSE;
455 }
456
457 METHOD(child_rekey_t, collide, void,
458 private_child_rekey_t *this, task_t *other)
459 {
460 /* the task manager only detects exchange collision, but not if
461 * the collision is for the same child. we check it here. */
462 if (other->get_type(other) == TASK_CHILD_REKEY)
463 {
464 private_child_rekey_t *rekey = (private_child_rekey_t*)other;
465 child_sa_t *other_child;
466
467 if (rekey->child_sa != this->child_sa)
468 { /* not the same child => no collision */
469 other->destroy(other);
470 return;
471 }
472 /* ignore passive tasks that did not successfully create a CHILD_SA */
473 other_child = rekey->child_create->get_child(rekey->child_create);
474 if (!other_child ||
475 other_child->get_state(other_child) != CHILD_INSTALLED)
476 {
477 other->destroy(other);
478 return;
479 }
480 }
481 else if (other->get_type(other) == TASK_CHILD_DELETE)
482 {
483 child_delete_t *del = (child_delete_t*)other;
484 if (is_redundant(this, del->get_child(del)))
485 {
486 this->other_child_destroyed = TRUE;
487 other->destroy(other);
488 return;
489 }
490 if (del->get_child(del) != this->child_sa)
491 {
492 /* not the same child => no collision */
493 other->destroy(other);
494 return;
495 }
496 }
497 else
498 {
499 /* any other task is not critical for collisions, ignore */
500 other->destroy(other);
501 return;
502 }
503 DBG1(DBG_IKE, "detected %N collision with %N", task_type_names,
504 TASK_CHILD_REKEY, task_type_names, other->get_type(other));
505 DESTROY_IF(this->collision);
506 this->collision = other;
507 }
508
509 METHOD(task_t, migrate, void,
510 private_child_rekey_t *this, ike_sa_t *ike_sa)
511 {
512 if (this->child_create)
513 {
514 this->child_create->task.migrate(&this->child_create->task, ike_sa);
515 }
516 if (this->child_delete)
517 {
518 this->child_delete->task.migrate(&this->child_delete->task, ike_sa);
519 }
520 DESTROY_IF(this->collision);
521
522 this->ike_sa = ike_sa;
523 this->collision = NULL;
524 }
525
526 METHOD(task_t, destroy, void,
527 private_child_rekey_t *this)
528 {
529 if (this->child_create)
530 {
531 this->child_create->task.destroy(&this->child_create->task);
532 }
533 if (this->child_delete)
534 {
535 this->child_delete->task.destroy(&this->child_delete->task);
536 }
537 DESTROY_IF(this->collision);
538 free(this);
539 }
540
541 /*
542 * Described in header.
543 */
544 child_rekey_t *child_rekey_create(ike_sa_t *ike_sa, protocol_id_t protocol,
545 uint32_t spi)
546 {
547 private_child_rekey_t *this;
548
549 INIT(this,
550 .public = {
551 .task = {
552 .get_type = _get_type,
553 .migrate = _migrate,
554 .destroy = _destroy,
555 },
556 .is_redundant = _is_redundant,
557 .collide = _collide,
558 },
559 .ike_sa = ike_sa,
560 .protocol = protocol,
561 .spi = spi,
562 );
563
564 if (protocol != PROTO_NONE)
565 {
566 this->public.task.build = _build_i;
567 this->public.task.process = _process_i;
568 this->initiator = TRUE;
569 this->child_create = NULL;
570 }
571 else
572 {
573 this->public.task.build = _build_r;
574 this->public.task.process = _process_r;
575 this->initiator = FALSE;
576 this->child_create = child_create_create(ike_sa, NULL, TRUE, NULL, NULL);
577 }
578
579 return &this->public;
580 }