Do not touch child from collision if peer deleted it
[strongswan.git] / src / libcharon / sa / 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/tasks/child_create.h>
22 #include <sa/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 /**
132 * Implementation of task_t.build for initiator
133 */
134 static status_t build_i(private_child_rekey_t *this, message_t *message)
135 {
136 notify_payload_t *notify;
137 u_int32_t reqid;
138 child_cfg_t *config;
139
140 this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, this->protocol,
141 this->spi, TRUE);
142 if (!this->child_sa)
143 { /* check if it is an outbound CHILD_SA */
144 this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, this->protocol,
145 this->spi, FALSE);
146 if (!this->child_sa)
147 { /* CHILD_SA is gone, unable to rekey. As an empty CREATE_CHILD_SA
148 * exchange is invalid, we fall back to an INFORMATIONAL exchange.*/
149 message->set_exchange_type(message, INFORMATIONAL);
150 return SUCCESS;
151 }
152 /* we work only with the inbound SPI */
153 this->spi = this->child_sa->get_spi(this->child_sa, TRUE);
154 }
155 config = this->child_sa->get_config(this->child_sa);
156
157 /* we just need the rekey notify ... */
158 notify = notify_payload_create_from_protocol_and_type(this->protocol,
159 REKEY_SA);
160 notify->set_spi(notify, this->spi);
161 message->add_payload(message, (payload_t*)notify);
162
163 /* ... our CHILD_CREATE task does the hard work for us. */
164 if (!this->child_create)
165 {
166 this->child_create = child_create_create(this->ike_sa, config, TRUE,
167 NULL, NULL);
168 }
169 reqid = this->child_sa->get_reqid(this->child_sa);
170 this->child_create->use_reqid(this->child_create, reqid);
171 this->child_create->task.build(&this->child_create->task, message);
172
173 this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
174
175 return NEED_MORE;
176 }
177
178 /**
179 * Implementation of task_t.process for initiator
180 */
181 static status_t process_r(private_child_rekey_t *this, message_t *message)
182 {
183 /* let the CHILD_CREATE task process the message */
184 this->child_create->task.process(&this->child_create->task, message);
185
186 find_child(this, message);
187
188 return NEED_MORE;
189 }
190
191 /**
192 * Implementation of task_t.build for responder
193 */
194 static status_t build_r(private_child_rekey_t *this, message_t *message)
195 {
196 u_int32_t reqid;
197
198 if (this->child_sa == NULL ||
199 this->child_sa->get_state(this->child_sa) == CHILD_DELETING)
200 {
201 DBG1(DBG_IKE, "unable to rekey, CHILD_SA not found");
202 message->add_notify(message, TRUE, NO_PROPOSAL_CHOSEN, chunk_empty);
203 return SUCCESS;
204 }
205
206 /* let the CHILD_CREATE task build the response */
207 reqid = this->child_sa->get_reqid(this->child_sa);
208 this->child_create->use_reqid(this->child_create, reqid);
209 this->child_create->task.build(&this->child_create->task, message);
210
211 if (message->get_payload(message, SECURITY_ASSOCIATION) == NULL)
212 {
213 /* rekeying failed, reuse old child */
214 this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
215 return SUCCESS;
216 }
217
218 this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
219
220 /* invoke rekey hook */
221 charon->bus->child_rekey(charon->bus, this->child_sa,
222 this->child_create->get_child(this->child_create));
223 return SUCCESS;
224 }
225
226 /**
227 * Handle a rekey collision
228 */
229 static child_sa_t *handle_collision(private_child_rekey_t *this)
230 {
231 child_sa_t *to_delete;
232
233 if (this->collision->get_type(this->collision) == CHILD_REKEY)
234 {
235 chunk_t this_nonce, other_nonce;
236 private_child_rekey_t *other = (private_child_rekey_t*)this->collision;
237
238 this_nonce = this->child_create->get_lower_nonce(this->child_create);
239 other_nonce = other->child_create->get_lower_nonce(other->child_create);
240
241 /* if we have the lower nonce, delete rekeyed SA. If not, delete
242 * the redundant. */
243 if (memcmp(this_nonce.ptr, other_nonce.ptr,
244 min(this_nonce.len, other_nonce.len)) < 0)
245 {
246 child_sa_t *child_sa;
247
248 DBG1(DBG_IKE, "CHILD_SA rekey collision won, "
249 "deleting rekeyed child");
250 to_delete = this->child_sa;
251 /* don't touch child other created, it has already been deleted */
252 if (!this->other_child_destroyed)
253 {
254 /* disable close action for the redundand child */
255 child_sa = other->child_create->get_child(other->child_create);
256 child_sa->set_close_action(child_sa, ACTION_NONE);
257 }
258 }
259 else
260 {
261 DBG1(DBG_IKE, "CHILD_SA rekey collision lost, "
262 "deleting redundant child");
263 to_delete = this->child_create->get_child(this->child_create);
264 }
265 }
266 else
267 { /* CHILD_DELETE */
268 child_delete_t *del = (child_delete_t*)this->collision;
269
270 /* we didn't had a chance to compare the nonces, so we delete
271 * the CHILD_SA the other is not deleting. */
272 if (del->get_child(del) != this->child_sa)
273 {
274 DBG1(DBG_IKE, "CHILD_SA rekey/delete collision, "
275 "deleting rekeyed child");
276 to_delete = this->child_sa;
277 }
278 else
279 {
280 DBG1(DBG_IKE, "CHILD_SA rekey/delete collision, "
281 "deleting redundant child");
282 to_delete = this->child_create->get_child(this->child_create);
283 }
284 }
285 return to_delete;
286 }
287
288 /**
289 * Implementation of task_t.process for initiator
290 */
291 static status_t process_i(private_child_rekey_t *this, message_t *message)
292 {
293 protocol_id_t protocol;
294 u_int32_t spi;
295 child_sa_t *to_delete;
296
297 if (message->get_notify(message, NO_ADDITIONAL_SAS))
298 {
299 DBG1(DBG_IKE, "peer seems to not support CHILD_SA rekeying, "
300 "starting reauthentication");
301 this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
302 charon->processor->queue_job(charon->processor,
303 (job_t*)rekey_ike_sa_job_create(
304 this->ike_sa->get_id(this->ike_sa), TRUE));
305 return SUCCESS;
306 }
307
308 if (this->child_create->task.process(&this->child_create->task,
309 message) == NEED_MORE)
310 {
311 /* bad DH group while rekeying, try again */
312 this->child_create->task.migrate(&this->child_create->task, this->ike_sa);
313 return NEED_MORE;
314 }
315 if (message->get_payload(message, SECURITY_ASSOCIATION) == NULL)
316 {
317 /* establishing new child failed, reuse old. but not when we
318 * recieved a delete in the meantime */
319 if (!(this->collision &&
320 this->collision->get_type(this->collision) == CHILD_DELETE))
321 {
322 job_t *job;
323 u_int32_t retry = RETRY_INTERVAL - (random() % RETRY_JITTER);
324
325 job = (job_t*)rekey_child_sa_job_create(
326 this->child_sa->get_reqid(this->child_sa),
327 this->child_sa->get_protocol(this->child_sa),
328 this->child_sa->get_spi(this->child_sa, TRUE));
329 DBG1(DBG_IKE, "CHILD_SA rekeying failed, "
330 "trying again in %d seconds", retry);
331 this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
332 charon->scheduler->schedule_job(charon->scheduler, job, retry);
333 }
334 return SUCCESS;
335 }
336
337 /* check for rekey collisions */
338 if (this->collision)
339 {
340 to_delete = handle_collision(this);
341 }
342 else
343 {
344 to_delete = this->child_sa;
345 }
346
347 if (to_delete != this->child_create->get_child(this->child_create))
348 { /* invoke rekey hook if rekeying successful */
349 charon->bus->child_rekey(charon->bus, this->child_sa,
350 this->child_create->get_child(this->child_create));
351 }
352
353 if (to_delete == NULL)
354 {
355 return SUCCESS;
356 }
357 spi = to_delete->get_spi(to_delete, TRUE);
358 protocol = to_delete->get_protocol(to_delete);
359
360 /* rekeying done, delete the obsolete CHILD_SA using a subtask */
361 this->child_delete = child_delete_create(this->ike_sa, protocol, spi);
362 this->public.task.build = (status_t(*)(task_t*,message_t*))build_i_delete;
363 this->public.task.process = (status_t(*)(task_t*,message_t*))process_i_delete;
364
365 return NEED_MORE;
366 }
367
368 /**
369 * Implementation of task_t.get_type
370 */
371 static task_type_t get_type(private_child_rekey_t *this)
372 {
373 return CHILD_REKEY;
374 }
375
376 /**
377 * Implementation of child_rekey_t.collide
378 */
379 static void collide(private_child_rekey_t *this, task_t *other)
380 {
381 /* the task manager only detects exchange collision, but not if
382 * the collision is for the same child. we check it here. */
383 if (other->get_type(other) == CHILD_REKEY)
384 {
385 private_child_rekey_t *rekey = (private_child_rekey_t*)other;
386 if (rekey == NULL || rekey->child_sa != this->child_sa)
387 {
388 /* not the same child => no collision */
389 other->destroy(other);
390 return;
391 }
392 }
393 else if (other->get_type(other) == CHILD_DELETE)
394 {
395 child_delete_t *del = (child_delete_t*)other;
396 if (del->get_child(del) == this->child_create->get_child(this->child_create))
397 {
398 /* peer deletes redundant child created in collision */
399 this->other_child_destroyed = TRUE;
400 other->destroy(other);
401 return;
402 }
403 if (del == NULL || del->get_child(del) != this->child_sa)
404 {
405 /* not the same child => no collision */
406 other->destroy(other);
407 return;
408 }
409 }
410 else
411 {
412 /* any other task is not critical for collisisions, ignore */
413 other->destroy(other);
414 return;
415 }
416 DESTROY_IF(this->collision);
417 this->collision = other;
418 }
419
420 /**
421 * Implementation of task_t.migrate
422 */
423 static void migrate(private_child_rekey_t *this, ike_sa_t *ike_sa)
424 {
425 if (this->child_create)
426 {
427 this->child_create->task.migrate(&this->child_create->task, ike_sa);
428 }
429 if (this->child_delete)
430 {
431 this->child_delete->task.migrate(&this->child_delete->task, ike_sa);
432 }
433 DESTROY_IF(this->collision);
434
435 this->ike_sa = ike_sa;
436 this->collision = NULL;
437 }
438
439 /**
440 * Implementation of task_t.destroy
441 */
442 static void destroy(private_child_rekey_t *this)
443 {
444 if (this->child_create)
445 {
446 this->child_create->task.destroy(&this->child_create->task);
447 }
448 if (this->child_delete)
449 {
450 this->child_delete->task.destroy(&this->child_delete->task);
451 }
452 DESTROY_IF(this->collision);
453 free(this);
454 }
455
456 /*
457 * Described in header.
458 */
459 child_rekey_t *child_rekey_create(ike_sa_t *ike_sa, protocol_id_t protocol,
460 u_int32_t spi)
461 {
462 private_child_rekey_t *this = malloc_thing(private_child_rekey_t);
463
464 this->public.collide = (void (*)(child_rekey_t*,task_t*))collide;
465 this->public.task.get_type = (task_type_t(*)(task_t*))get_type;
466 this->public.task.migrate = (void(*)(task_t*,ike_sa_t*))migrate;
467 this->public.task.destroy = (void(*)(task_t*))destroy;
468 if (protocol != PROTO_NONE)
469 {
470 this->public.task.build = (status_t(*)(task_t*,message_t*))build_i;
471 this->public.task.process = (status_t(*)(task_t*,message_t*))process_i;
472 this->initiator = TRUE;
473 this->child_create = NULL;
474 }
475 else
476 {
477 this->public.task.build = (status_t(*)(task_t*,message_t*))build_r;
478 this->public.task.process = (status_t(*)(task_t*,message_t*))process_r;
479 this->initiator = FALSE;
480 this->child_create = child_create_create(ike_sa, NULL, TRUE, NULL, NULL);
481 }
482
483 this->ike_sa = ike_sa;
484 this->child_sa = NULL;
485 this->protocol = protocol;
486 this->spi = spi;
487 this->collision = NULL;
488 this->child_delete = NULL;
489 this->other_child_destroyed = FALSE;
490
491 return &this->public;
492 }