Convert empty CREATE_CHILD_SA exchange to an INFORMATIONAL
[strongswan.git] / src / charon / 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 /**
81 * Implementation of task_t.build for initiator, after rekeying
82 */
83 static status_t build_i_delete(private_child_rekey_t *this, message_t *message)
84 {
85 /* update exchange type to INFORMATIONAL for the delete */
86 message->set_exchange_type(message, INFORMATIONAL);
87
88 return this->child_delete->task.build(&this->child_delete->task, message);
89 }
90
91 /**
92 * Implementation of task_t.process for initiator, after rekeying
93 */
94 static status_t process_i_delete(private_child_rekey_t *this, message_t *message)
95 {
96 return this->child_delete->task.process(&this->child_delete->task, message);
97 }
98
99 /**
100 * find a child using the REKEY_SA notify
101 */
102 static void find_child(private_child_rekey_t *this, message_t *message)
103 {
104 notify_payload_t *notify;
105 protocol_id_t protocol;
106 u_int32_t spi;
107
108 notify = message->get_notify(message, REKEY_SA);
109 if (notify)
110 {
111 protocol = notify->get_protocol_id(notify);
112 spi = notify->get_spi(notify);
113
114 if (protocol == PROTO_ESP || protocol == PROTO_AH)
115 {
116 this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, protocol,
117 spi, FALSE);
118 }
119 }
120 }
121
122 /**
123 * Implementation of task_t.build for initiator
124 */
125 static status_t build_i(private_child_rekey_t *this, message_t *message)
126 {
127 notify_payload_t *notify;
128 u_int32_t reqid;
129 child_cfg_t *config;
130
131 this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, this->protocol,
132 this->spi, TRUE);
133 if (!this->child_sa)
134 { /* check if it is an outbound CHILD_SA */
135 this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, this->protocol,
136 this->spi, FALSE);
137 if (!this->child_sa)
138 { /* CHILD_SA is gone, unable to rekey. As an empty CREATE_CHILD_SA
139 * exchange is invalid, we fall back to an INFORMATIONAL exchange.*/
140 message->set_exchange_type(message, INFORMATIONAL);
141 return SUCCESS;
142 }
143 /* we work only with the inbound SPI */
144 this->spi = this->child_sa->get_spi(this->child_sa, TRUE);
145 }
146 config = this->child_sa->get_config(this->child_sa);
147
148 /* we just need the rekey notify ... */
149 notify = notify_payload_create_from_protocol_and_type(this->protocol,
150 REKEY_SA);
151 notify->set_spi(notify, this->spi);
152 message->add_payload(message, (payload_t*)notify);
153
154 /* ... our CHILD_CREATE task does the hard work for us. */
155 reqid = this->child_sa->get_reqid(this->child_sa);
156 this->child_create = child_create_create(this->ike_sa, config, TRUE,
157 NULL, NULL);
158 this->child_create->use_reqid(this->child_create, reqid);
159 this->child_create->task.build(&this->child_create->task, message);
160
161 this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
162
163 return NEED_MORE;
164 }
165
166 /**
167 * Implementation of task_t.process for initiator
168 */
169 static status_t process_r(private_child_rekey_t *this, message_t *message)
170 {
171 /* let the CHILD_CREATE task process the message */
172 this->child_create->task.process(&this->child_create->task, message);
173
174 find_child(this, message);
175
176 return NEED_MORE;
177 }
178
179 /**
180 * Implementation of task_t.build for responder
181 */
182 static status_t build_r(private_child_rekey_t *this, message_t *message)
183 {
184 u_int32_t reqid;
185
186 if (this->child_sa == NULL ||
187 this->child_sa->get_state(this->child_sa) == CHILD_DELETING)
188 {
189 DBG1(DBG_IKE, "unable to rekey, CHILD_SA not found");
190 message->add_notify(message, TRUE, NO_PROPOSAL_CHOSEN, chunk_empty);
191 return SUCCESS;
192 }
193
194 /* let the CHILD_CREATE task build the response */
195 reqid = this->child_sa->get_reqid(this->child_sa);
196 this->child_create->use_reqid(this->child_create, reqid);
197 this->child_create->task.build(&this->child_create->task, message);
198
199 if (message->get_payload(message, SECURITY_ASSOCIATION) == NULL)
200 {
201 /* rekeying failed, reuse old child */
202 this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
203 return SUCCESS;
204 }
205
206 this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
207
208 /* invoke rekey hook */
209 charon->bus->child_rekey(charon->bus, this->child_sa,
210 this->child_create->get_child(this->child_create));
211 return SUCCESS;
212 }
213
214 /**
215 * Implementation of task_t.process for initiator
216 */
217 static status_t process_i(private_child_rekey_t *this, message_t *message)
218 {
219 protocol_id_t protocol;
220 u_int32_t spi;
221 child_sa_t *to_delete;
222
223 if (message->get_notify(message, NO_ADDITIONAL_SAS))
224 {
225 DBG1(DBG_IKE, "peer seems to not support CHILD_SA rekeying, "
226 "starting reauthentication");
227 this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
228 charon->processor->queue_job(charon->processor,
229 (job_t*)rekey_ike_sa_job_create(
230 this->ike_sa->get_id(this->ike_sa), TRUE));
231 return SUCCESS;
232 }
233
234 if (this->child_create->task.process(&this->child_create->task,
235 message) == NEED_MORE)
236 {
237 /* bad DH group while rekeying, try again */
238 this->child_create->task.migrate(&this->child_create->task, this->ike_sa);
239 return NEED_MORE;
240 }
241 if (message->get_payload(message, SECURITY_ASSOCIATION) == NULL)
242 {
243 /* establishing new child failed, reuse old. but not when we
244 * recieved a delete in the meantime */
245 if (!(this->collision &&
246 this->collision->get_type(this->collision) == CHILD_DELETE))
247 {
248 job_t *job;
249 u_int32_t retry = RETRY_INTERVAL - (random() % RETRY_JITTER);
250
251 job = (job_t*)rekey_child_sa_job_create(
252 this->child_sa->get_reqid(this->child_sa),
253 this->child_sa->get_protocol(this->child_sa),
254 this->child_sa->get_spi(this->child_sa, TRUE));
255 DBG1(DBG_IKE, "CHILD_SA rekeying failed, "
256 "trying again in %d seconds", retry);
257 this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
258 charon->scheduler->schedule_job(charon->scheduler, job, retry);
259 }
260 return SUCCESS;
261 }
262
263 to_delete = this->child_sa;
264
265 /* check for rekey collisions */
266 if (this->collision &&
267 this->collision->get_type(this->collision) == CHILD_REKEY)
268 {
269 chunk_t this_nonce, other_nonce;
270 private_child_rekey_t *other = (private_child_rekey_t*)this->collision;
271
272 this_nonce = this->child_create->get_lower_nonce(this->child_create);
273 other_nonce = other->child_create->get_lower_nonce(other->child_create);
274
275 /* if we have the lower nonce, delete rekeyed SA. If not, delete
276 * the redundant. */
277 if (memcmp(this_nonce.ptr, other_nonce.ptr,
278 min(this_nonce.len, other_nonce.len)) < 0)
279 {
280 DBG1(DBG_IKE, "CHILD_SA rekey collision won, deleting rekeyed child");
281 }
282 else
283 {
284 DBG1(DBG_IKE, "CHILD_SA rekey collision lost, deleting redundant child");
285 to_delete = this->child_create->get_child(this->child_create);
286 if (to_delete == NULL)
287 {
288 /* ooops, should not happen, fallback */
289 to_delete = this->child_sa;
290 }
291 }
292 }
293
294 if (to_delete != this->child_create->get_child(this->child_create))
295 { /* invoke rekey hook if rekeying successful */
296 charon->bus->child_rekey(charon->bus, this->child_sa,
297 this->child_create->get_child(this->child_create));
298 }
299
300 spi = to_delete->get_spi(to_delete, TRUE);
301 protocol = to_delete->get_protocol(to_delete);
302
303 /* rekeying done, delete the obsolete CHILD_SA using a subtask */
304 this->child_delete = child_delete_create(this->ike_sa, protocol, spi);
305 this->public.task.build = (status_t(*)(task_t*,message_t*))build_i_delete;
306 this->public.task.process = (status_t(*)(task_t*,message_t*))process_i_delete;
307
308 return NEED_MORE;
309 }
310
311 /**
312 * Implementation of task_t.get_type
313 */
314 static task_type_t get_type(private_child_rekey_t *this)
315 {
316 return CHILD_REKEY;
317 }
318
319 /**
320 * Implementation of child_rekey_t.collide
321 */
322 static void collide(private_child_rekey_t *this, task_t *other)
323 {
324 /* the task manager only detects exchange collision, but not if
325 * the collision is for the same child. we check it here. */
326 if (other->get_type(other) == CHILD_REKEY)
327 {
328 private_child_rekey_t *rekey = (private_child_rekey_t*)other;
329 if (rekey == NULL || rekey->child_sa != this->child_sa)
330 {
331 /* not the same child => no collision */
332 return;
333 }
334 }
335 else if (other->get_type(other) == CHILD_DELETE)
336 {
337 child_delete_t *del = (child_delete_t*)other;
338 if (del == NULL || del->get_child(del) != this->child_sa)
339 {
340 /* not the same child => no collision */
341 return;
342 }
343 }
344 else
345 {
346 /* any other task is not critical for collisisions, ignore */
347 return;
348 }
349 DESTROY_IF(this->collision);
350 this->collision = other;
351 }
352
353 /**
354 * Implementation of task_t.migrate
355 */
356 static void migrate(private_child_rekey_t *this, ike_sa_t *ike_sa)
357 {
358 if (this->child_create)
359 {
360 this->child_create->task.migrate(&this->child_create->task, ike_sa);
361 }
362 if (this->child_delete)
363 {
364 this->child_delete->task.migrate(&this->child_delete->task, ike_sa);
365 }
366 DESTROY_IF(this->collision);
367
368 this->ike_sa = ike_sa;
369 this->collision = NULL;
370 }
371
372 /**
373 * Implementation of task_t.destroy
374 */
375 static void destroy(private_child_rekey_t *this)
376 {
377 if (this->child_create)
378 {
379 this->child_create->task.destroy(&this->child_create->task);
380 }
381 if (this->child_delete)
382 {
383 this->child_delete->task.destroy(&this->child_delete->task);
384 }
385 DESTROY_IF(this->collision);
386 free(this);
387 }
388
389 /*
390 * Described in header.
391 */
392 child_rekey_t *child_rekey_create(ike_sa_t *ike_sa, protocol_id_t protocol,
393 u_int32_t spi)
394 {
395 private_child_rekey_t *this = malloc_thing(private_child_rekey_t);
396
397 this->public.collide = (void (*)(child_rekey_t*,task_t*))collide;
398 this->public.task.get_type = (task_type_t(*)(task_t*))get_type;
399 this->public.task.migrate = (void(*)(task_t*,ike_sa_t*))migrate;
400 this->public.task.destroy = (void(*)(task_t*))destroy;
401 if (protocol != PROTO_NONE)
402 {
403 this->public.task.build = (status_t(*)(task_t*,message_t*))build_i;
404 this->public.task.process = (status_t(*)(task_t*,message_t*))process_i;
405 this->initiator = TRUE;
406 this->child_create = NULL;
407 }
408 else
409 {
410 this->public.task.build = (status_t(*)(task_t*,message_t*))build_r;
411 this->public.task.process = (status_t(*)(task_t*,message_t*))process_r;
412 this->initiator = FALSE;
413 this->child_create = child_create_create(ike_sa, NULL, TRUE, NULL, NULL);
414 }
415
416 this->ike_sa = ike_sa;
417 this->child_sa = NULL;
418 this->protocol = protocol;
419 this->spi = spi;
420 this->collision = NULL;
421 this->child_delete = NULL;
422
423 return &this->public;
424 }