Defer CHILD_SA rekeying if allocating an SPI fails
[strongswan.git] / 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_reqid(this->child_sa),
100 this->child_sa->get_protocol(this->child_sa),
101 this->child_sa->get_spi(this->child_sa, TRUE));
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 /* we just need the rekey notify ... */
174 notify = notify_payload_create_from_protocol_and_type(NOTIFY,
175 this->protocol, REKEY_SA);
176 notify->set_spi(notify, this->spi);
177 message->add_payload(message, (payload_t*)notify);
178
179 /* ... our CHILD_CREATE task does the hard work for us. */
180 if (!this->child_create)
181 {
182 this->child_create = child_create_create(this->ike_sa,
183 config->get_ref(config), TRUE, NULL, NULL);
184 }
185 reqid = this->child_sa->get_reqid(this->child_sa);
186 this->child_create->use_reqid(this->child_create, reqid);
187
188 if (this->child_create->task.build(&this->child_create->task,
189 message) != NEED_MORE)
190 {
191 schedule_delayed_rekey(this);
192 return FAILED;
193 }
194 this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
195
196 return NEED_MORE;
197 }
198
199 METHOD(task_t, process_r, status_t,
200 private_child_rekey_t *this, message_t *message)
201 {
202 /* let the CHILD_CREATE task process the message */
203 this->child_create->task.process(&this->child_create->task, message);
204
205 find_child(this, message);
206
207 return NEED_MORE;
208 }
209
210 METHOD(task_t, build_r, status_t,
211 private_child_rekey_t *this, message_t *message)
212 {
213 child_cfg_t *config;
214 u_int32_t reqid;
215
216 if (this->child_sa == NULL ||
217 this->child_sa->get_state(this->child_sa) == CHILD_DELETING)
218 {
219 DBG1(DBG_IKE, "unable to rekey, CHILD_SA not found");
220 message->add_notify(message, TRUE, NO_PROPOSAL_CHOSEN, chunk_empty);
221 return SUCCESS;
222 }
223
224 /* let the CHILD_CREATE task build the response */
225 reqid = this->child_sa->get_reqid(this->child_sa);
226 this->child_create->use_reqid(this->child_create, reqid);
227 config = this->child_sa->get_config(this->child_sa);
228 this->child_create->set_config(this->child_create, config->get_ref(config));
229 this->child_create->task.build(&this->child_create->task, message);
230
231 if (message->get_payload(message, SECURITY_ASSOCIATION) == NULL)
232 {
233 /* rekeying failed, reuse old child */
234 this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
235 return SUCCESS;
236 }
237
238 this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
239
240 /* invoke rekey hook */
241 charon->bus->child_rekey(charon->bus, this->child_sa,
242 this->child_create->get_child(this->child_create));
243 return SUCCESS;
244 }
245
246 /**
247 * Handle a rekey collision
248 */
249 static child_sa_t *handle_collision(private_child_rekey_t *this)
250 {
251 child_sa_t *to_delete;
252
253 if (this->collision->get_type(this->collision) == TASK_CHILD_REKEY)
254 {
255 chunk_t this_nonce, other_nonce;
256 private_child_rekey_t *other = (private_child_rekey_t*)this->collision;
257
258 this_nonce = this->child_create->get_lower_nonce(this->child_create);
259 other_nonce = other->child_create->get_lower_nonce(other->child_create);
260
261 /* if we have the lower nonce, delete rekeyed SA. If not, delete
262 * the redundant. */
263 if (memcmp(this_nonce.ptr, other_nonce.ptr,
264 min(this_nonce.len, other_nonce.len)) > 0)
265 {
266 child_sa_t *child_sa;
267
268 DBG1(DBG_IKE, "CHILD_SA rekey collision won, deleting old child");
269 to_delete = this->child_sa;
270 /* don't touch child other created, it has already been deleted */
271 if (!this->other_child_destroyed)
272 {
273 /* disable close action for the redundand child */
274 child_sa = other->child_create->get_child(other->child_create);
275 if (child_sa)
276 {
277 child_sa->set_close_action(child_sa, ACTION_NONE);
278 }
279 }
280 }
281 else
282 {
283 DBG1(DBG_IKE, "CHILD_SA rekey collision lost, "
284 "deleting rekeyed child");
285 to_delete = this->child_create->get_child(this->child_create);
286 }
287 }
288 else
289 { /* CHILD_DELETE */
290 child_delete_t *del = (child_delete_t*)this->collision;
291
292 /* we didn't had a chance to compare the nonces, so we delete
293 * the CHILD_SA the other is not deleting. */
294 if (del->get_child(del) != this->child_sa)
295 {
296 DBG1(DBG_IKE, "CHILD_SA rekey/delete collision, "
297 "deleting rekeyed child");
298 to_delete = this->child_sa;
299 }
300 else
301 {
302 DBG1(DBG_IKE, "CHILD_SA rekey/delete collision, "
303 "deleting redundant child");
304 to_delete = this->child_create->get_child(this->child_create);
305 }
306 }
307 return to_delete;
308 }
309
310 METHOD(task_t, process_i, status_t,
311 private_child_rekey_t *this, message_t *message)
312 {
313 protocol_id_t protocol;
314 u_int32_t spi;
315 child_sa_t *to_delete;
316
317 if (message->get_notify(message, NO_ADDITIONAL_SAS))
318 {
319 DBG1(DBG_IKE, "peer seems to not support CHILD_SA rekeying, "
320 "starting reauthentication");
321 this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
322 lib->processor->queue_job(lib->processor,
323 (job_t*)rekey_ike_sa_job_create(
324 this->ike_sa->get_id(this->ike_sa), TRUE));
325 return SUCCESS;
326 }
327
328 if (this->child_create->task.process(&this->child_create->task,
329 message) == NEED_MORE)
330 {
331 /* bad DH group while rekeying, try again */
332 this->child_create->task.migrate(&this->child_create->task, this->ike_sa);
333 return NEED_MORE;
334 }
335 if (message->get_payload(message, SECURITY_ASSOCIATION) == NULL)
336 {
337 /* establishing new child failed, reuse old. but not when we
338 * received a delete in the meantime */
339 if (!(this->collision &&
340 this->collision->get_type(this->collision) == TASK_CHILD_DELETE))
341 {
342 schedule_delayed_rekey(this);
343 }
344 return SUCCESS;
345 }
346
347 /* check for rekey collisions */
348 if (this->collision)
349 {
350 to_delete = handle_collision(this);
351 }
352 else
353 {
354 to_delete = this->child_sa;
355 }
356
357 if (to_delete != this->child_create->get_child(this->child_create))
358 { /* invoke rekey hook if rekeying successful */
359 charon->bus->child_rekey(charon->bus, this->child_sa,
360 this->child_create->get_child(this->child_create));
361 }
362
363 if (to_delete == NULL)
364 {
365 return SUCCESS;
366 }
367 spi = to_delete->get_spi(to_delete, TRUE);
368 protocol = to_delete->get_protocol(to_delete);
369
370 /* rekeying done, delete the obsolete CHILD_SA using a subtask */
371 this->child_delete = child_delete_create(this->ike_sa, protocol, spi, FALSE);
372 this->public.task.build = (status_t(*)(task_t*,message_t*))build_i_delete;
373 this->public.task.process = (status_t(*)(task_t*,message_t*))process_i_delete;
374
375 return NEED_MORE;
376 }
377
378 METHOD(task_t, get_type, task_type_t,
379 private_child_rekey_t *this)
380 {
381 return TASK_CHILD_REKEY;
382 }
383
384 METHOD(child_rekey_t, collide, void,
385 private_child_rekey_t *this, task_t *other)
386 {
387 /* the task manager only detects exchange collision, but not if
388 * the collision is for the same child. we check it here. */
389 if (other->get_type(other) == TASK_CHILD_REKEY)
390 {
391 private_child_rekey_t *rekey = (private_child_rekey_t*)other;
392 if (rekey->child_sa != this->child_sa)
393 {
394 /* not the same child => no collision */
395 other->destroy(other);
396 return;
397 }
398 }
399 else if (other->get_type(other) == TASK_CHILD_DELETE)
400 {
401 child_delete_t *del = (child_delete_t*)other;
402 if (del->get_child(del) == this->child_create->get_child(this->child_create))
403 {
404 /* peer deletes redundant child created in collision */
405 this->other_child_destroyed = TRUE;
406 other->destroy(other);
407 return;
408 }
409 if (del->get_child(del) != this->child_sa)
410 {
411 /* not the same child => no collision */
412 other->destroy(other);
413 return;
414 }
415 }
416 else
417 {
418 /* any other task is not critical for collisisions, ignore */
419 other->destroy(other);
420 return;
421 }
422 DBG1(DBG_IKE, "detected %N collision with %N", task_type_names,
423 TASK_CHILD_REKEY, task_type_names, other->get_type(other));
424 DESTROY_IF(this->collision);
425 this->collision = other;
426 }
427
428 METHOD(task_t, migrate, void,
429 private_child_rekey_t *this, ike_sa_t *ike_sa)
430 {
431 if (this->child_create)
432 {
433 this->child_create->task.migrate(&this->child_create->task, ike_sa);
434 }
435 if (this->child_delete)
436 {
437 this->child_delete->task.migrate(&this->child_delete->task, ike_sa);
438 }
439 DESTROY_IF(this->collision);
440
441 this->ike_sa = ike_sa;
442 this->collision = NULL;
443 }
444
445 METHOD(task_t, destroy, void,
446 private_child_rekey_t *this)
447 {
448 if (this->child_create)
449 {
450 this->child_create->task.destroy(&this->child_create->task);
451 }
452 if (this->child_delete)
453 {
454 this->child_delete->task.destroy(&this->child_delete->task);
455 }
456 DESTROY_IF(this->collision);
457 free(this);
458 }
459
460 /*
461 * Described in header.
462 */
463 child_rekey_t *child_rekey_create(ike_sa_t *ike_sa, protocol_id_t protocol,
464 u_int32_t spi)
465 {
466 private_child_rekey_t *this;
467
468 INIT(this,
469 .public = {
470 .task = {
471 .get_type = _get_type,
472 .migrate = _migrate,
473 .destroy = _destroy,
474 },
475 .collide = _collide,
476 },
477 .ike_sa = ike_sa,
478 .protocol = protocol,
479 .spi = spi,
480 );
481
482 if (protocol != PROTO_NONE)
483 {
484 this->public.task.build = _build_i;
485 this->public.task.process = _process_i;
486 this->initiator = TRUE;
487 this->child_create = NULL;
488 }
489 else
490 {
491 this->public.task.build = _build_r;
492 this->public.task.process = _process_r;
493 this->initiator = FALSE;
494 this->child_create = child_create_create(ike_sa, NULL, TRUE, NULL, NULL);
495 }
496
497 return &this->public;
498 }