libipsec: Enforce a minimum of 256 for SPIs
[strongswan.git] / src / libipsec / ipsec_sa_mgr.c
1 /*
2 * Copyright (C) 2012-2017 Tobias Brunner
3 * Copyright (C) 2012 Giuliano Grassi
4 * Copyright (C) 2012 Ralf Sager
5 * 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 "ipsec.h"
19 #include "ipsec_sa_mgr.h"
20
21 #include <utils/debug.h>
22 #include <library.h>
23 #include <processing/jobs/callback_job.h>
24 #include <threading/condvar.h>
25 #include <threading/mutex.h>
26 #include <collections/hashtable.h>
27 #include <collections/linked_list.h>
28
29 typedef struct private_ipsec_sa_mgr_t private_ipsec_sa_mgr_t;
30
31 /**
32 * Private additions to ipsec_sa_mgr_t.
33 */
34 struct private_ipsec_sa_mgr_t {
35
36 /**
37 * Public members of ipsec_sa_mgr_t.
38 */
39 ipsec_sa_mgr_t public;
40
41 /**
42 * Installed SAs
43 */
44 linked_list_t *sas;
45
46 /**
47 * SPIs allocated using get_spi()
48 */
49 hashtable_t *allocated_spis;
50
51 /**
52 * Mutex used to synchronize access to the SA manager
53 */
54 mutex_t *mutex;
55
56 /**
57 * RNG used to generate SPIs
58 */
59 rng_t *rng;
60 };
61
62 /**
63 * Struct to keep track of locked IPsec SAs
64 */
65 typedef struct {
66
67 /**
68 * IPsec SA
69 */
70 ipsec_sa_t *sa;
71
72 /**
73 * Set if this SA is currently in use by a thread
74 */
75 bool locked;
76
77 /**
78 * Condvar used by threads to wait for this entry
79 */
80 condvar_t *condvar;
81
82 /**
83 * Number of threads waiting for this entry
84 */
85 u_int waiting_threads;
86
87 /**
88 * Set if this entry is awaiting deletion
89 */
90 bool awaits_deletion;
91
92 } ipsec_sa_entry_t;
93
94 /**
95 * Helper struct for expiration events
96 */
97 typedef struct {
98
99 /**
100 * IPsec SA manager
101 */
102 private_ipsec_sa_mgr_t *manager;
103
104 /**
105 * Entry that expired
106 */
107 ipsec_sa_entry_t *entry;
108
109 /**
110 * 0 if this is a hard expire, otherwise the offset in s (soft->hard)
111 */
112 uint32_t hard_offset;
113
114 } ipsec_sa_expired_t;
115
116 /*
117 * Used for the hash table of allocated SPIs
118 */
119 static bool spi_equals(uint32_t *spi, uint32_t *other_spi)
120 {
121 return *spi == *other_spi;
122 }
123
124 static u_int spi_hash(uint32_t *spi)
125 {
126 return chunk_hash(chunk_from_thing(*spi));
127 }
128
129 /**
130 * Create an SA entry
131 */
132 static ipsec_sa_entry_t *create_entry(ipsec_sa_t *sa)
133 {
134 ipsec_sa_entry_t *this;
135
136 INIT(this,
137 .condvar = condvar_create(CONDVAR_TYPE_DEFAULT),
138 .sa = sa,
139 );
140 return this;
141 }
142
143 /**
144 * Destroy an SA entry
145 */
146 static void destroy_entry(ipsec_sa_entry_t *entry)
147 {
148 entry->condvar->destroy(entry->condvar);
149 entry->sa->destroy(entry->sa);
150 free(entry);
151 }
152
153 /**
154 * Makes sure an entry is safe to remove
155 * Must be called with this->mutex held.
156 *
157 * @return TRUE if entry can be removed, FALSE if entry is already
158 * being removed by another thread
159 */
160 static bool wait_remove_entry(private_ipsec_sa_mgr_t *this,
161 ipsec_sa_entry_t *entry)
162 {
163 if (entry->awaits_deletion)
164 {
165 /* this will be deleted by another thread already */
166 return FALSE;
167 }
168 entry->awaits_deletion = TRUE;
169 while (entry->locked)
170 {
171 entry->condvar->wait(entry->condvar, this->mutex);
172 }
173 while (entry->waiting_threads > 0)
174 {
175 entry->condvar->broadcast(entry->condvar);
176 entry->condvar->wait(entry->condvar, this->mutex);
177 }
178 return TRUE;
179 }
180
181 /**
182 * Waits until an is available and then locks it.
183 * Must only be called with this->mutex held
184 */
185 static bool wait_for_entry(private_ipsec_sa_mgr_t *this,
186 ipsec_sa_entry_t *entry)
187 {
188 while (entry->locked && !entry->awaits_deletion)
189 {
190 entry->waiting_threads++;
191 entry->condvar->wait(entry->condvar, this->mutex);
192 entry->waiting_threads--;
193 }
194 if (entry->awaits_deletion)
195 {
196 /* others may still be waiting, */
197 entry->condvar->signal(entry->condvar);
198 return FALSE;
199 }
200 entry->locked = TRUE;
201 return TRUE;
202 }
203
204 /**
205 * Flushes all entries
206 * Must be called with this->mutex held.
207 */
208 static void flush_entries(private_ipsec_sa_mgr_t *this)
209 {
210 ipsec_sa_entry_t *current;
211 enumerator_t *enumerator;
212
213 DBG2(DBG_ESP, "flushing SAD");
214
215 enumerator = this->sas->create_enumerator(this->sas);
216 while (enumerator->enumerate(enumerator, (void**)&current))
217 {
218 if (wait_remove_entry(this, current))
219 {
220 this->sas->remove_at(this->sas, enumerator);
221 destroy_entry(current);
222 }
223 }
224 enumerator->destroy(enumerator);
225 }
226
227 /*
228 * Different match functions to find SAs in the linked list
229 */
230 static bool match_entry_by_ptr(ipsec_sa_entry_t *item, ipsec_sa_entry_t *entry)
231 {
232 return item == entry;
233 }
234
235 static bool match_entry_by_sa_ptr(ipsec_sa_entry_t *item, ipsec_sa_t *sa)
236 {
237 return item->sa == sa;
238 }
239
240 static bool match_entry_by_spi_inbound(ipsec_sa_entry_t *item, uint32_t *spi,
241 bool *inbound)
242 {
243 return item->sa->get_spi(item->sa) == *spi &&
244 item->sa->is_inbound(item->sa) == *inbound;
245 }
246
247 static bool match_entry_by_spi_src_dst(ipsec_sa_entry_t *item, uint32_t *spi,
248 host_t *src, host_t *dst)
249 {
250 return item->sa->match_by_spi_src_dst(item->sa, *spi, src, dst);
251 }
252
253 static bool match_entry_by_reqid_inbound(ipsec_sa_entry_t *item,
254 uint32_t *reqid, bool *inbound)
255 {
256 return item->sa->match_by_reqid(item->sa, *reqid, *inbound);
257 }
258
259 static bool match_entry_by_spi_dst(ipsec_sa_entry_t *item, uint32_t *spi,
260 host_t *dst)
261 {
262 return item->sa->match_by_spi_dst(item->sa, *spi, dst);
263 }
264
265 /**
266 * Remove an entry
267 */
268 static bool remove_entry(private_ipsec_sa_mgr_t *this, ipsec_sa_entry_t *entry)
269 {
270 ipsec_sa_entry_t *current;
271 enumerator_t *enumerator;
272 bool removed = FALSE;
273
274 enumerator = this->sas->create_enumerator(this->sas);
275 while (enumerator->enumerate(enumerator, (void**)&current))
276 {
277 if (current == entry)
278 {
279 if (wait_remove_entry(this, current))
280 {
281 this->sas->remove_at(this->sas, enumerator);
282 removed = TRUE;
283 }
284 break;
285 }
286 }
287 enumerator->destroy(enumerator);
288 return removed;
289 }
290
291 /**
292 * Callback for expiration events
293 */
294 static job_requeue_t sa_expired(ipsec_sa_expired_t *expired)
295 {
296 private_ipsec_sa_mgr_t *this = expired->manager;
297
298 this->mutex->lock(this->mutex);
299 if (this->sas->find_first(this->sas, (void*)match_entry_by_ptr,
300 NULL, expired->entry) == SUCCESS)
301 {
302 uint32_t hard_offset;
303
304 hard_offset = expired->hard_offset;
305 expired->entry->sa->expire(expired->entry->sa, hard_offset == 0);
306 if (hard_offset)
307 { /* soft limit reached, schedule hard expire */
308 expired->hard_offset = 0;
309 this->mutex->unlock(this->mutex);
310 return JOB_RESCHEDULE(hard_offset);
311 }
312 /* hard limit reached */
313 if (remove_entry(this, expired->entry))
314 {
315 destroy_entry(expired->entry);
316 }
317 }
318 this->mutex->unlock(this->mutex);
319 return JOB_REQUEUE_NONE;
320 }
321
322 /**
323 * Schedule a job to handle IPsec SA expiration
324 */
325 static void schedule_expiration(private_ipsec_sa_mgr_t *this,
326 ipsec_sa_entry_t *entry)
327 {
328 lifetime_cfg_t *lifetime = entry->sa->get_lifetime(entry->sa);
329 ipsec_sa_expired_t *expired;
330 callback_job_t *job;
331 uint32_t timeout;
332
333 if (!lifetime->time.life)
334 { /* no expiration at all */
335 return;
336 }
337
338 INIT(expired,
339 .manager = this,
340 .entry = entry,
341 );
342
343 /* schedule a rekey first, a hard timeout will be scheduled then, if any */
344 expired->hard_offset = lifetime->time.life - lifetime->time.rekey;
345 timeout = lifetime->time.rekey;
346
347 if (lifetime->time.life <= lifetime->time.rekey ||
348 lifetime->time.rekey == 0)
349 { /* no rekey, schedule hard timeout */
350 expired->hard_offset = 0;
351 timeout = lifetime->time.life;
352 }
353
354 job = callback_job_create((callback_job_cb_t)sa_expired, expired,
355 (callback_job_cleanup_t)free, NULL);
356 lib->scheduler->schedule_job(lib->scheduler, (job_t*)job, timeout);
357 }
358
359 /**
360 * Remove all allocated SPIs
361 */
362 static void flush_allocated_spis(private_ipsec_sa_mgr_t *this)
363 {
364 enumerator_t *enumerator;
365 uint32_t *current;
366
367 DBG2(DBG_ESP, "flushing allocated SPIs");
368 enumerator = this->allocated_spis->create_enumerator(this->allocated_spis);
369 while (enumerator->enumerate(enumerator, NULL, (void**)&current))
370 {
371 this->allocated_spis->remove_at(this->allocated_spis, enumerator);
372 DBG2(DBG_ESP, " removed allocated SPI %.8x", ntohl(*current));
373 free(current);
374 }
375 enumerator->destroy(enumerator);
376 }
377
378 /**
379 * Pre-allocate an SPI for an inbound SA
380 */
381 static bool allocate_spi(private_ipsec_sa_mgr_t *this, uint32_t spi)
382 {
383 uint32_t *spi_alloc;
384
385 if (this->allocated_spis->get(this->allocated_spis, &spi) ||
386 this->sas->find_first(this->sas, (void*)match_entry_by_spi_inbound,
387 NULL, &spi, TRUE) == SUCCESS)
388 {
389 return FALSE;
390 }
391 spi_alloc = malloc_thing(uint32_t);
392 *spi_alloc = spi;
393 this->allocated_spis->put(this->allocated_spis, spi_alloc, spi_alloc);
394 return TRUE;
395 }
396
397 METHOD(ipsec_sa_mgr_t, get_spi, status_t,
398 private_ipsec_sa_mgr_t *this, host_t *src, host_t *dst, uint8_t protocol,
399 uint32_t *spi)
400 {
401 uint32_t spi_min, spi_max, spi_new;
402
403 spi_min = lib->settings->get_int(lib->settings, "%s.spi_min",
404 0x00000100, lib->ns);
405 spi_max = lib->settings->get_int(lib->settings, "%s.spi_max",
406 0xffffffff, lib->ns);
407 if (spi_min > spi_max)
408 {
409 spi_new = spi_min;
410 spi_min = spi_max;
411 spi_max = spi_new;
412 }
413 /* make sure the SPI is valid (not in range 0-255) */
414 spi_min = max(spi_min, 0x00000100);
415 spi_max = max(spi_max, 0x00000100);
416
417 this->mutex->lock(this->mutex);
418 if (!this->rng)
419 {
420 this->rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK);
421 if (!this->rng)
422 {
423 this->mutex->unlock(this->mutex);
424 DBG1(DBG_ESP, "failed to create RNG for SPI generation");
425 return FAILED;
426 }
427 }
428
429 do
430 {
431 if (!this->rng->get_bytes(this->rng, sizeof(spi_new),
432 (uint8_t*)&spi_new))
433 {
434 this->mutex->unlock(this->mutex);
435 DBG1(DBG_ESP, "failed to allocate SPI");
436 return FAILED;
437 }
438 spi_new = spi_min + spi_new % (spi_max - spi_min + 1);
439 spi_new = htonl(spi_new);
440 }
441 while (!allocate_spi(this, spi_new));
442 this->mutex->unlock(this->mutex);
443
444 *spi = spi_new;
445
446 DBG2(DBG_ESP, "allocated SPI %.8x", ntohl(*spi));
447 return SUCCESS;
448 }
449
450 METHOD(ipsec_sa_mgr_t, add_sa, status_t,
451 private_ipsec_sa_mgr_t *this, host_t *src, host_t *dst, uint32_t spi,
452 uint8_t protocol, uint32_t reqid, mark_t mark, uint32_t tfc,
453 lifetime_cfg_t *lifetime, uint16_t enc_alg, chunk_t enc_key,
454 uint16_t int_alg, chunk_t int_key, ipsec_mode_t mode, uint16_t ipcomp,
455 uint16_t cpi, bool initiator, bool encap, bool esn, bool inbound,
456 bool update)
457 {
458 ipsec_sa_entry_t *entry;
459 ipsec_sa_t *sa_new;
460
461 DBG2(DBG_ESP, "adding SAD entry with SPI %.8x and reqid {%u}",
462 ntohl(spi), reqid);
463 DBG2(DBG_ESP, " using encryption algorithm %N with key size %d",
464 encryption_algorithm_names, enc_alg, enc_key.len * 8);
465 DBG2(DBG_ESP, " using integrity algorithm %N with key size %d",
466 integrity_algorithm_names, int_alg, int_key.len * 8);
467
468 sa_new = ipsec_sa_create(spi, src, dst, protocol, reqid, mark, tfc,
469 lifetime, enc_alg, enc_key, int_alg, int_key, mode,
470 ipcomp, cpi, encap, esn, inbound);
471 if (!sa_new)
472 {
473 DBG1(DBG_ESP, "failed to create SAD entry");
474 return FAILED;
475 }
476
477 this->mutex->lock(this->mutex);
478
479 if (update)
480 { /* remove any pre-allocated SPIs */
481 uint32_t *spi_alloc;
482
483 spi_alloc = this->allocated_spis->remove(this->allocated_spis, &spi);
484 free(spi_alloc);
485 }
486
487 if (this->sas->find_first(this->sas, (void*)match_entry_by_spi_src_dst,
488 NULL, &spi, src, dst) == SUCCESS)
489 {
490 this->mutex->unlock(this->mutex);
491 DBG1(DBG_ESP, "failed to install SAD entry: already installed");
492 sa_new->destroy(sa_new);
493 return FAILED;
494 }
495
496 entry = create_entry(sa_new);
497 schedule_expiration(this, entry);
498 this->sas->insert_first(this->sas, entry);
499
500 this->mutex->unlock(this->mutex);
501 return SUCCESS;
502 }
503
504 METHOD(ipsec_sa_mgr_t, update_sa, status_t,
505 private_ipsec_sa_mgr_t *this, uint32_t spi, uint8_t protocol,
506 uint16_t cpi, host_t *src, host_t *dst, host_t *new_src, host_t *new_dst,
507 bool encap, bool new_encap, mark_t mark)
508 {
509 ipsec_sa_entry_t *entry = NULL;
510
511 DBG2(DBG_ESP, "updating SAD entry with SPI %.8x from %#H..%#H to %#H..%#H",
512 ntohl(spi), src, dst, new_src, new_dst);
513
514 if (!new_encap)
515 {
516 DBG1(DBG_ESP, "failed to update SAD entry: can't deactivate UDP "
517 "encapsulation");
518 return NOT_SUPPORTED;
519 }
520
521 this->mutex->lock(this->mutex);
522 if (this->sas->find_first(this->sas, (void*)match_entry_by_spi_src_dst,
523 (void**)&entry, &spi, src, dst) == SUCCESS &&
524 wait_for_entry(this, entry))
525 {
526 entry->sa->set_source(entry->sa, new_src);
527 entry->sa->set_destination(entry->sa, new_dst);
528 /* checkin the entry */
529 entry->locked = FALSE;
530 entry->condvar->signal(entry->condvar);
531 }
532 this->mutex->unlock(this->mutex);
533
534 if (!entry)
535 {
536 DBG1(DBG_ESP, "failed to update SAD entry: not found");
537 return FAILED;
538 }
539 return SUCCESS;
540 }
541
542 METHOD(ipsec_sa_mgr_t, query_sa, status_t,
543 private_ipsec_sa_mgr_t *this, host_t *src, host_t *dst,
544 uint32_t spi, uint8_t protocol, mark_t mark,
545 uint64_t *bytes, uint64_t *packets, time_t *time)
546 {
547 ipsec_sa_entry_t *entry = NULL;
548
549 this->mutex->lock(this->mutex);
550 if (this->sas->find_first(this->sas, (void*)match_entry_by_spi_src_dst,
551 (void**)&entry, &spi, src, dst) == SUCCESS &&
552 wait_for_entry(this, entry))
553 {
554 entry->sa->get_usestats(entry->sa, bytes, packets, time);
555 /* checkin the entry */
556 entry->locked = FALSE;
557 entry->condvar->signal(entry->condvar);
558 }
559 this->mutex->unlock(this->mutex);
560
561 return entry ? SUCCESS : NOT_FOUND;
562 }
563
564 METHOD(ipsec_sa_mgr_t, del_sa, status_t,
565 private_ipsec_sa_mgr_t *this, host_t *src, host_t *dst, uint32_t spi,
566 uint8_t protocol, uint16_t cpi, mark_t mark)
567 {
568 ipsec_sa_entry_t *current, *found = NULL;
569 enumerator_t *enumerator;
570
571 this->mutex->lock(this->mutex);
572 enumerator = this->sas->create_enumerator(this->sas);
573 while (enumerator->enumerate(enumerator, (void**)&current))
574 {
575 if (match_entry_by_spi_src_dst(current, &spi, src, dst))
576 {
577 if (wait_remove_entry(this, current))
578 {
579 this->sas->remove_at(this->sas, enumerator);
580 found = current;
581 }
582 break;
583 }
584 }
585 enumerator->destroy(enumerator);
586 this->mutex->unlock(this->mutex);
587
588 if (found)
589 {
590 DBG2(DBG_ESP, "deleted %sbound SAD entry with SPI %.8x",
591 found->sa->is_inbound(found->sa) ? "in" : "out", ntohl(spi));
592 destroy_entry(found);
593 return SUCCESS;
594 }
595 return FAILED;
596 }
597
598 METHOD(ipsec_sa_mgr_t, checkout_by_reqid, ipsec_sa_t*,
599 private_ipsec_sa_mgr_t *this, uint32_t reqid, bool inbound)
600 {
601 ipsec_sa_entry_t *entry;
602 ipsec_sa_t *sa = NULL;
603
604 this->mutex->lock(this->mutex);
605 if (this->sas->find_first(this->sas, (void*)match_entry_by_reqid_inbound,
606 (void**)&entry, &reqid, &inbound) == SUCCESS &&
607 wait_for_entry(this, entry))
608 {
609 sa = entry->sa;
610 }
611 this->mutex->unlock(this->mutex);
612 return sa;
613 }
614
615 METHOD(ipsec_sa_mgr_t, checkout_by_spi, ipsec_sa_t*,
616 private_ipsec_sa_mgr_t *this, uint32_t spi, host_t *dst)
617 {
618 ipsec_sa_entry_t *entry;
619 ipsec_sa_t *sa = NULL;
620
621 this->mutex->lock(this->mutex);
622 if (this->sas->find_first(this->sas, (void*)match_entry_by_spi_dst,
623 (void**)&entry, &spi, dst) == SUCCESS &&
624 wait_for_entry(this, entry))
625 {
626 sa = entry->sa;
627 }
628 this->mutex->unlock(this->mutex);
629 return sa;
630 }
631
632 METHOD(ipsec_sa_mgr_t, checkin, void,
633 private_ipsec_sa_mgr_t *this, ipsec_sa_t *sa)
634 {
635 ipsec_sa_entry_t *entry;
636
637 this->mutex->lock(this->mutex);
638 if (this->sas->find_first(this->sas, (void*)match_entry_by_sa_ptr,
639 (void**)&entry, sa) == SUCCESS)
640 {
641 if (entry->locked)
642 {
643 entry->locked = FALSE;
644 entry->condvar->signal(entry->condvar);
645 }
646 }
647 this->mutex->unlock(this->mutex);
648 }
649
650 METHOD(ipsec_sa_mgr_t, flush_sas, status_t,
651 private_ipsec_sa_mgr_t *this)
652 {
653 this->mutex->lock(this->mutex);
654 flush_entries(this);
655 this->mutex->unlock(this->mutex);
656 return SUCCESS;
657 }
658
659 METHOD(ipsec_sa_mgr_t, destroy, void,
660 private_ipsec_sa_mgr_t *this)
661 {
662 this->mutex->lock(this->mutex);
663 flush_entries(this);
664 flush_allocated_spis(this);
665 this->mutex->unlock(this->mutex);
666
667 this->allocated_spis->destroy(this->allocated_spis);
668 this->sas->destroy(this->sas);
669
670 this->mutex->destroy(this->mutex);
671 DESTROY_IF(this->rng);
672 free(this);
673 }
674
675 /**
676 * Described in header.
677 */
678 ipsec_sa_mgr_t *ipsec_sa_mgr_create()
679 {
680 private_ipsec_sa_mgr_t *this;
681
682 INIT(this,
683 .public = {
684 .get_spi = _get_spi,
685 .add_sa = _add_sa,
686 .update_sa = _update_sa,
687 .query_sa = _query_sa,
688 .del_sa = _del_sa,
689 .checkout_by_spi = _checkout_by_spi,
690 .checkout_by_reqid = _checkout_by_reqid,
691 .checkin = _checkin,
692 .flush_sas = _flush_sas,
693 .destroy = _destroy,
694 },
695 .sas = linked_list_create(),
696 .mutex = mutex_create(MUTEX_TYPE_DEFAULT),
697 .allocated_spis = hashtable_create((hashtable_hash_t)spi_hash,
698 (hashtable_equals_t)spi_equals, 16),
699 );
700
701 return &this->public;
702 }