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[XFRM]: fix incorrect xfrm_policy_afinfo_lock use
[mirror_ubuntu-zesty-kernel.git] / net / xfrm / xfrm_policy.c
1 /*
2 * xfrm_policy.c
3 *
4 * Changes:
5 * Mitsuru KANDA @USAGI
6 * Kazunori MIYAZAWA @USAGI
7 * Kunihiro Ishiguro <kunihiro@ipinfusion.com>
8 * IPv6 support
9 * Kazunori MIYAZAWA @USAGI
10 * YOSHIFUJI Hideaki
11 * Split up af-specific portion
12 * Derek Atkins <derek@ihtfp.com> Add the post_input processor
13 *
14 */
15
16 #include <linux/config.h>
17 #include <linux/slab.h>
18 #include <linux/kmod.h>
19 #include <linux/list.h>
20 #include <linux/spinlock.h>
21 #include <linux/workqueue.h>
22 #include <linux/notifier.h>
23 #include <linux/netdevice.h>
24 #include <linux/netfilter.h>
25 #include <linux/module.h>
26 #include <net/xfrm.h>
27 #include <net/ip.h>
28
29 DEFINE_MUTEX(xfrm_cfg_mutex);
30 EXPORT_SYMBOL(xfrm_cfg_mutex);
31
32 static DEFINE_RWLOCK(xfrm_policy_lock);
33
34 struct xfrm_policy *xfrm_policy_list[XFRM_POLICY_MAX*2];
35 EXPORT_SYMBOL(xfrm_policy_list);
36
37 static DEFINE_RWLOCK(xfrm_policy_afinfo_lock);
38 static struct xfrm_policy_afinfo *xfrm_policy_afinfo[NPROTO];
39
40 static kmem_cache_t *xfrm_dst_cache __read_mostly;
41
42 static struct work_struct xfrm_policy_gc_work;
43 static struct list_head xfrm_policy_gc_list =
44 LIST_HEAD_INIT(xfrm_policy_gc_list);
45 static DEFINE_SPINLOCK(xfrm_policy_gc_lock);
46
47 static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family);
48 static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo);
49
50 int xfrm_register_type(struct xfrm_type *type, unsigned short family)
51 {
52 struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
53 struct xfrm_type_map *typemap;
54 int err = 0;
55
56 if (unlikely(afinfo == NULL))
57 return -EAFNOSUPPORT;
58 typemap = afinfo->type_map;
59
60 write_lock_bh(&typemap->lock);
61 if (likely(typemap->map[type->proto] == NULL))
62 typemap->map[type->proto] = type;
63 else
64 err = -EEXIST;
65 write_unlock_bh(&typemap->lock);
66 xfrm_policy_put_afinfo(afinfo);
67 return err;
68 }
69 EXPORT_SYMBOL(xfrm_register_type);
70
71 int xfrm_unregister_type(struct xfrm_type *type, unsigned short family)
72 {
73 struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
74 struct xfrm_type_map *typemap;
75 int err = 0;
76
77 if (unlikely(afinfo == NULL))
78 return -EAFNOSUPPORT;
79 typemap = afinfo->type_map;
80
81 write_lock_bh(&typemap->lock);
82 if (unlikely(typemap->map[type->proto] != type))
83 err = -ENOENT;
84 else
85 typemap->map[type->proto] = NULL;
86 write_unlock_bh(&typemap->lock);
87 xfrm_policy_put_afinfo(afinfo);
88 return err;
89 }
90 EXPORT_SYMBOL(xfrm_unregister_type);
91
92 struct xfrm_type *xfrm_get_type(u8 proto, unsigned short family)
93 {
94 struct xfrm_policy_afinfo *afinfo;
95 struct xfrm_type_map *typemap;
96 struct xfrm_type *type;
97 int modload_attempted = 0;
98
99 retry:
100 afinfo = xfrm_policy_get_afinfo(family);
101 if (unlikely(afinfo == NULL))
102 return NULL;
103 typemap = afinfo->type_map;
104
105 read_lock(&typemap->lock);
106 type = typemap->map[proto];
107 if (unlikely(type && !try_module_get(type->owner)))
108 type = NULL;
109 read_unlock(&typemap->lock);
110 if (!type && !modload_attempted) {
111 xfrm_policy_put_afinfo(afinfo);
112 request_module("xfrm-type-%d-%d",
113 (int) family, (int) proto);
114 modload_attempted = 1;
115 goto retry;
116 }
117
118 xfrm_policy_put_afinfo(afinfo);
119 return type;
120 }
121
122 int xfrm_dst_lookup(struct xfrm_dst **dst, struct flowi *fl,
123 unsigned short family)
124 {
125 struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
126 int err = 0;
127
128 if (unlikely(afinfo == NULL))
129 return -EAFNOSUPPORT;
130
131 if (likely(afinfo->dst_lookup != NULL))
132 err = afinfo->dst_lookup(dst, fl);
133 else
134 err = -EINVAL;
135 xfrm_policy_put_afinfo(afinfo);
136 return err;
137 }
138 EXPORT_SYMBOL(xfrm_dst_lookup);
139
140 void xfrm_put_type(struct xfrm_type *type)
141 {
142 module_put(type->owner);
143 }
144
145 static inline unsigned long make_jiffies(long secs)
146 {
147 if (secs >= (MAX_SCHEDULE_TIMEOUT-1)/HZ)
148 return MAX_SCHEDULE_TIMEOUT-1;
149 else
150 return secs*HZ;
151 }
152
153 static void xfrm_policy_timer(unsigned long data)
154 {
155 struct xfrm_policy *xp = (struct xfrm_policy*)data;
156 unsigned long now = (unsigned long)xtime.tv_sec;
157 long next = LONG_MAX;
158 int warn = 0;
159 int dir;
160
161 read_lock(&xp->lock);
162
163 if (xp->dead)
164 goto out;
165
166 dir = xfrm_policy_id2dir(xp->index);
167
168 if (xp->lft.hard_add_expires_seconds) {
169 long tmo = xp->lft.hard_add_expires_seconds +
170 xp->curlft.add_time - now;
171 if (tmo <= 0)
172 goto expired;
173 if (tmo < next)
174 next = tmo;
175 }
176 if (xp->lft.hard_use_expires_seconds) {
177 long tmo = xp->lft.hard_use_expires_seconds +
178 (xp->curlft.use_time ? : xp->curlft.add_time) - now;
179 if (tmo <= 0)
180 goto expired;
181 if (tmo < next)
182 next = tmo;
183 }
184 if (xp->lft.soft_add_expires_seconds) {
185 long tmo = xp->lft.soft_add_expires_seconds +
186 xp->curlft.add_time - now;
187 if (tmo <= 0) {
188 warn = 1;
189 tmo = XFRM_KM_TIMEOUT;
190 }
191 if (tmo < next)
192 next = tmo;
193 }
194 if (xp->lft.soft_use_expires_seconds) {
195 long tmo = xp->lft.soft_use_expires_seconds +
196 (xp->curlft.use_time ? : xp->curlft.add_time) - now;
197 if (tmo <= 0) {
198 warn = 1;
199 tmo = XFRM_KM_TIMEOUT;
200 }
201 if (tmo < next)
202 next = tmo;
203 }
204
205 if (warn)
206 km_policy_expired(xp, dir, 0, 0);
207 if (next != LONG_MAX &&
208 !mod_timer(&xp->timer, jiffies + make_jiffies(next)))
209 xfrm_pol_hold(xp);
210
211 out:
212 read_unlock(&xp->lock);
213 xfrm_pol_put(xp);
214 return;
215
216 expired:
217 read_unlock(&xp->lock);
218 if (!xfrm_policy_delete(xp, dir))
219 km_policy_expired(xp, dir, 1, 0);
220 xfrm_pol_put(xp);
221 }
222
223
224 /* Allocate xfrm_policy. Not used here, it is supposed to be used by pfkeyv2
225 * SPD calls.
226 */
227
228 struct xfrm_policy *xfrm_policy_alloc(gfp_t gfp)
229 {
230 struct xfrm_policy *policy;
231
232 policy = kmalloc(sizeof(struct xfrm_policy), gfp);
233
234 if (policy) {
235 memset(policy, 0, sizeof(struct xfrm_policy));
236 atomic_set(&policy->refcnt, 1);
237 rwlock_init(&policy->lock);
238 init_timer(&policy->timer);
239 policy->timer.data = (unsigned long)policy;
240 policy->timer.function = xfrm_policy_timer;
241 }
242 return policy;
243 }
244 EXPORT_SYMBOL(xfrm_policy_alloc);
245
246 /* Destroy xfrm_policy: descendant resources must be released to this moment. */
247
248 void __xfrm_policy_destroy(struct xfrm_policy *policy)
249 {
250 BUG_ON(!policy->dead);
251
252 BUG_ON(policy->bundles);
253
254 if (del_timer(&policy->timer))
255 BUG();
256
257 security_xfrm_policy_free(policy);
258 kfree(policy);
259 }
260 EXPORT_SYMBOL(__xfrm_policy_destroy);
261
262 static void xfrm_policy_gc_kill(struct xfrm_policy *policy)
263 {
264 struct dst_entry *dst;
265
266 while ((dst = policy->bundles) != NULL) {
267 policy->bundles = dst->next;
268 dst_free(dst);
269 }
270
271 if (del_timer(&policy->timer))
272 atomic_dec(&policy->refcnt);
273
274 if (atomic_read(&policy->refcnt) > 1)
275 flow_cache_flush();
276
277 xfrm_pol_put(policy);
278 }
279
280 static void xfrm_policy_gc_task(void *data)
281 {
282 struct xfrm_policy *policy;
283 struct list_head *entry, *tmp;
284 struct list_head gc_list = LIST_HEAD_INIT(gc_list);
285
286 spin_lock_bh(&xfrm_policy_gc_lock);
287 list_splice_init(&xfrm_policy_gc_list, &gc_list);
288 spin_unlock_bh(&xfrm_policy_gc_lock);
289
290 list_for_each_safe(entry, tmp, &gc_list) {
291 policy = list_entry(entry, struct xfrm_policy, list);
292 xfrm_policy_gc_kill(policy);
293 }
294 }
295
296 /* Rule must be locked. Release descentant resources, announce
297 * entry dead. The rule must be unlinked from lists to the moment.
298 */
299
300 static void xfrm_policy_kill(struct xfrm_policy *policy)
301 {
302 int dead;
303
304 write_lock_bh(&policy->lock);
305 dead = policy->dead;
306 policy->dead = 1;
307 write_unlock_bh(&policy->lock);
308
309 if (unlikely(dead)) {
310 WARN_ON(1);
311 return;
312 }
313
314 spin_lock(&xfrm_policy_gc_lock);
315 list_add(&policy->list, &xfrm_policy_gc_list);
316 spin_unlock(&xfrm_policy_gc_lock);
317
318 schedule_work(&xfrm_policy_gc_work);
319 }
320
321 /* Generate new index... KAME seems to generate them ordered by cost
322 * of an absolute inpredictability of ordering of rules. This will not pass. */
323 static u32 xfrm_gen_index(int dir)
324 {
325 u32 idx;
326 struct xfrm_policy *p;
327 static u32 idx_generator;
328
329 for (;;) {
330 idx = (idx_generator | dir);
331 idx_generator += 8;
332 if (idx == 0)
333 idx = 8;
334 for (p = xfrm_policy_list[dir]; p; p = p->next) {
335 if (p->index == idx)
336 break;
337 }
338 if (!p)
339 return idx;
340 }
341 }
342
343 int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl)
344 {
345 struct xfrm_policy *pol, **p;
346 struct xfrm_policy *delpol = NULL;
347 struct xfrm_policy **newpos = NULL;
348 struct dst_entry *gc_list;
349
350 write_lock_bh(&xfrm_policy_lock);
351 for (p = &xfrm_policy_list[dir]; (pol=*p)!=NULL;) {
352 if (!delpol && memcmp(&policy->selector, &pol->selector, sizeof(pol->selector)) == 0 &&
353 xfrm_sec_ctx_match(pol->security, policy->security)) {
354 if (excl) {
355 write_unlock_bh(&xfrm_policy_lock);
356 return -EEXIST;
357 }
358 *p = pol->next;
359 delpol = pol;
360 if (policy->priority > pol->priority)
361 continue;
362 } else if (policy->priority >= pol->priority) {
363 p = &pol->next;
364 continue;
365 }
366 if (!newpos)
367 newpos = p;
368 if (delpol)
369 break;
370 p = &pol->next;
371 }
372 if (newpos)
373 p = newpos;
374 xfrm_pol_hold(policy);
375 policy->next = *p;
376 *p = policy;
377 atomic_inc(&flow_cache_genid);
378 policy->index = delpol ? delpol->index : xfrm_gen_index(dir);
379 policy->curlft.add_time = (unsigned long)xtime.tv_sec;
380 policy->curlft.use_time = 0;
381 if (!mod_timer(&policy->timer, jiffies + HZ))
382 xfrm_pol_hold(policy);
383 write_unlock_bh(&xfrm_policy_lock);
384
385 if (delpol)
386 xfrm_policy_kill(delpol);
387
388 read_lock_bh(&xfrm_policy_lock);
389 gc_list = NULL;
390 for (policy = policy->next; policy; policy = policy->next) {
391 struct dst_entry *dst;
392
393 write_lock(&policy->lock);
394 dst = policy->bundles;
395 if (dst) {
396 struct dst_entry *tail = dst;
397 while (tail->next)
398 tail = tail->next;
399 tail->next = gc_list;
400 gc_list = dst;
401
402 policy->bundles = NULL;
403 }
404 write_unlock(&policy->lock);
405 }
406 read_unlock_bh(&xfrm_policy_lock);
407
408 while (gc_list) {
409 struct dst_entry *dst = gc_list;
410
411 gc_list = dst->next;
412 dst_free(dst);
413 }
414
415 return 0;
416 }
417 EXPORT_SYMBOL(xfrm_policy_insert);
418
419 struct xfrm_policy *xfrm_policy_bysel_ctx(int dir, struct xfrm_selector *sel,
420 struct xfrm_sec_ctx *ctx, int delete)
421 {
422 struct xfrm_policy *pol, **p;
423
424 write_lock_bh(&xfrm_policy_lock);
425 for (p = &xfrm_policy_list[dir]; (pol=*p)!=NULL; p = &pol->next) {
426 if ((memcmp(sel, &pol->selector, sizeof(*sel)) == 0) &&
427 (xfrm_sec_ctx_match(ctx, pol->security))) {
428 xfrm_pol_hold(pol);
429 if (delete)
430 *p = pol->next;
431 break;
432 }
433 }
434 write_unlock_bh(&xfrm_policy_lock);
435
436 if (pol && delete) {
437 atomic_inc(&flow_cache_genid);
438 xfrm_policy_kill(pol);
439 }
440 return pol;
441 }
442 EXPORT_SYMBOL(xfrm_policy_bysel_ctx);
443
444 struct xfrm_policy *xfrm_policy_byid(int dir, u32 id, int delete)
445 {
446 struct xfrm_policy *pol, **p;
447
448 write_lock_bh(&xfrm_policy_lock);
449 for (p = &xfrm_policy_list[dir]; (pol=*p)!=NULL; p = &pol->next) {
450 if (pol->index == id) {
451 xfrm_pol_hold(pol);
452 if (delete)
453 *p = pol->next;
454 break;
455 }
456 }
457 write_unlock_bh(&xfrm_policy_lock);
458
459 if (pol && delete) {
460 atomic_inc(&flow_cache_genid);
461 xfrm_policy_kill(pol);
462 }
463 return pol;
464 }
465 EXPORT_SYMBOL(xfrm_policy_byid);
466
467 void xfrm_policy_flush(void)
468 {
469 struct xfrm_policy *xp;
470 int dir;
471
472 write_lock_bh(&xfrm_policy_lock);
473 for (dir = 0; dir < XFRM_POLICY_MAX; dir++) {
474 while ((xp = xfrm_policy_list[dir]) != NULL) {
475 xfrm_policy_list[dir] = xp->next;
476 write_unlock_bh(&xfrm_policy_lock);
477
478 xfrm_policy_kill(xp);
479
480 write_lock_bh(&xfrm_policy_lock);
481 }
482 }
483 atomic_inc(&flow_cache_genid);
484 write_unlock_bh(&xfrm_policy_lock);
485 }
486 EXPORT_SYMBOL(xfrm_policy_flush);
487
488 int xfrm_policy_walk(int (*func)(struct xfrm_policy *, int, int, void*),
489 void *data)
490 {
491 struct xfrm_policy *xp;
492 int dir;
493 int count = 0;
494 int error = 0;
495
496 read_lock_bh(&xfrm_policy_lock);
497 for (dir = 0; dir < 2*XFRM_POLICY_MAX; dir++) {
498 for (xp = xfrm_policy_list[dir]; xp; xp = xp->next)
499 count++;
500 }
501
502 if (count == 0) {
503 error = -ENOENT;
504 goto out;
505 }
506
507 for (dir = 0; dir < 2*XFRM_POLICY_MAX; dir++) {
508 for (xp = xfrm_policy_list[dir]; xp; xp = xp->next) {
509 error = func(xp, dir%XFRM_POLICY_MAX, --count, data);
510 if (error)
511 goto out;
512 }
513 }
514
515 out:
516 read_unlock_bh(&xfrm_policy_lock);
517 return error;
518 }
519 EXPORT_SYMBOL(xfrm_policy_walk);
520
521 /* Find policy to apply to this flow. */
522
523 static void xfrm_policy_lookup(struct flowi *fl, u32 sk_sid, u16 family, u8 dir,
524 void **objp, atomic_t **obj_refp)
525 {
526 struct xfrm_policy *pol;
527
528 read_lock_bh(&xfrm_policy_lock);
529 for (pol = xfrm_policy_list[dir]; pol; pol = pol->next) {
530 struct xfrm_selector *sel = &pol->selector;
531 int match;
532
533 if (pol->family != family)
534 continue;
535
536 match = xfrm_selector_match(sel, fl, family);
537
538 if (match) {
539 if (!security_xfrm_policy_lookup(pol, sk_sid, dir)) {
540 xfrm_pol_hold(pol);
541 break;
542 }
543 }
544 }
545 read_unlock_bh(&xfrm_policy_lock);
546 if ((*objp = (void *) pol) != NULL)
547 *obj_refp = &pol->refcnt;
548 }
549
550 static inline int policy_to_flow_dir(int dir)
551 {
552 if (XFRM_POLICY_IN == FLOW_DIR_IN &&
553 XFRM_POLICY_OUT == FLOW_DIR_OUT &&
554 XFRM_POLICY_FWD == FLOW_DIR_FWD)
555 return dir;
556 switch (dir) {
557 default:
558 case XFRM_POLICY_IN:
559 return FLOW_DIR_IN;
560 case XFRM_POLICY_OUT:
561 return FLOW_DIR_OUT;
562 case XFRM_POLICY_FWD:
563 return FLOW_DIR_FWD;
564 };
565 }
566
567 static struct xfrm_policy *xfrm_sk_policy_lookup(struct sock *sk, int dir, struct flowi *fl, u32 sk_sid)
568 {
569 struct xfrm_policy *pol;
570
571 read_lock_bh(&xfrm_policy_lock);
572 if ((pol = sk->sk_policy[dir]) != NULL) {
573 int match = xfrm_selector_match(&pol->selector, fl,
574 sk->sk_family);
575 int err = 0;
576
577 if (match)
578 err = security_xfrm_policy_lookup(pol, sk_sid, policy_to_flow_dir(dir));
579
580 if (match && !err)
581 xfrm_pol_hold(pol);
582 else
583 pol = NULL;
584 }
585 read_unlock_bh(&xfrm_policy_lock);
586 return pol;
587 }
588
589 static void __xfrm_policy_link(struct xfrm_policy *pol, int dir)
590 {
591 pol->next = xfrm_policy_list[dir];
592 xfrm_policy_list[dir] = pol;
593 xfrm_pol_hold(pol);
594 }
595
596 static struct xfrm_policy *__xfrm_policy_unlink(struct xfrm_policy *pol,
597 int dir)
598 {
599 struct xfrm_policy **polp;
600
601 for (polp = &xfrm_policy_list[dir];
602 *polp != NULL; polp = &(*polp)->next) {
603 if (*polp == pol) {
604 *polp = pol->next;
605 return pol;
606 }
607 }
608 return NULL;
609 }
610
611 int xfrm_policy_delete(struct xfrm_policy *pol, int dir)
612 {
613 write_lock_bh(&xfrm_policy_lock);
614 pol = __xfrm_policy_unlink(pol, dir);
615 write_unlock_bh(&xfrm_policy_lock);
616 if (pol) {
617 if (dir < XFRM_POLICY_MAX)
618 atomic_inc(&flow_cache_genid);
619 xfrm_policy_kill(pol);
620 return 0;
621 }
622 return -ENOENT;
623 }
624 EXPORT_SYMBOL(xfrm_policy_delete);
625
626 int xfrm_sk_policy_insert(struct sock *sk, int dir, struct xfrm_policy *pol)
627 {
628 struct xfrm_policy *old_pol;
629
630 write_lock_bh(&xfrm_policy_lock);
631 old_pol = sk->sk_policy[dir];
632 sk->sk_policy[dir] = pol;
633 if (pol) {
634 pol->curlft.add_time = (unsigned long)xtime.tv_sec;
635 pol->index = xfrm_gen_index(XFRM_POLICY_MAX+dir);
636 __xfrm_policy_link(pol, XFRM_POLICY_MAX+dir);
637 }
638 if (old_pol)
639 __xfrm_policy_unlink(old_pol, XFRM_POLICY_MAX+dir);
640 write_unlock_bh(&xfrm_policy_lock);
641
642 if (old_pol) {
643 xfrm_policy_kill(old_pol);
644 }
645 return 0;
646 }
647
648 static struct xfrm_policy *clone_policy(struct xfrm_policy *old, int dir)
649 {
650 struct xfrm_policy *newp = xfrm_policy_alloc(GFP_ATOMIC);
651
652 if (newp) {
653 newp->selector = old->selector;
654 if (security_xfrm_policy_clone(old, newp)) {
655 kfree(newp);
656 return NULL; /* ENOMEM */
657 }
658 newp->lft = old->lft;
659 newp->curlft = old->curlft;
660 newp->action = old->action;
661 newp->flags = old->flags;
662 newp->xfrm_nr = old->xfrm_nr;
663 newp->index = old->index;
664 memcpy(newp->xfrm_vec, old->xfrm_vec,
665 newp->xfrm_nr*sizeof(struct xfrm_tmpl));
666 write_lock_bh(&xfrm_policy_lock);
667 __xfrm_policy_link(newp, XFRM_POLICY_MAX+dir);
668 write_unlock_bh(&xfrm_policy_lock);
669 xfrm_pol_put(newp);
670 }
671 return newp;
672 }
673
674 int __xfrm_sk_clone_policy(struct sock *sk)
675 {
676 struct xfrm_policy *p0 = sk->sk_policy[0],
677 *p1 = sk->sk_policy[1];
678
679 sk->sk_policy[0] = sk->sk_policy[1] = NULL;
680 if (p0 && (sk->sk_policy[0] = clone_policy(p0, 0)) == NULL)
681 return -ENOMEM;
682 if (p1 && (sk->sk_policy[1] = clone_policy(p1, 1)) == NULL)
683 return -ENOMEM;
684 return 0;
685 }
686
687 /* Resolve list of templates for the flow, given policy. */
688
689 static int
690 xfrm_tmpl_resolve(struct xfrm_policy *policy, struct flowi *fl,
691 struct xfrm_state **xfrm,
692 unsigned short family)
693 {
694 int nx;
695 int i, error;
696 xfrm_address_t *daddr = xfrm_flowi_daddr(fl, family);
697 xfrm_address_t *saddr = xfrm_flowi_saddr(fl, family);
698
699 for (nx=0, i = 0; i < policy->xfrm_nr; i++) {
700 struct xfrm_state *x;
701 xfrm_address_t *remote = daddr;
702 xfrm_address_t *local = saddr;
703 struct xfrm_tmpl *tmpl = &policy->xfrm_vec[i];
704
705 if (tmpl->mode) {
706 remote = &tmpl->id.daddr;
707 local = &tmpl->saddr;
708 }
709
710 x = xfrm_state_find(remote, local, fl, tmpl, policy, &error, family);
711
712 if (x && x->km.state == XFRM_STATE_VALID) {
713 xfrm[nx++] = x;
714 daddr = remote;
715 saddr = local;
716 continue;
717 }
718 if (x) {
719 error = (x->km.state == XFRM_STATE_ERROR ?
720 -EINVAL : -EAGAIN);
721 xfrm_state_put(x);
722 }
723
724 if (!tmpl->optional)
725 goto fail;
726 }
727 return nx;
728
729 fail:
730 for (nx--; nx>=0; nx--)
731 xfrm_state_put(xfrm[nx]);
732 return error;
733 }
734
735 /* Check that the bundle accepts the flow and its components are
736 * still valid.
737 */
738
739 static struct dst_entry *
740 xfrm_find_bundle(struct flowi *fl, struct xfrm_policy *policy, unsigned short family)
741 {
742 struct dst_entry *x;
743 struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
744 if (unlikely(afinfo == NULL))
745 return ERR_PTR(-EINVAL);
746 x = afinfo->find_bundle(fl, policy);
747 xfrm_policy_put_afinfo(afinfo);
748 return x;
749 }
750
751 /* Allocate chain of dst_entry's, attach known xfrm's, calculate
752 * all the metrics... Shortly, bundle a bundle.
753 */
754
755 static int
756 xfrm_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
757 struct flowi *fl, struct dst_entry **dst_p,
758 unsigned short family)
759 {
760 int err;
761 struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
762 if (unlikely(afinfo == NULL))
763 return -EINVAL;
764 err = afinfo->bundle_create(policy, xfrm, nx, fl, dst_p);
765 xfrm_policy_put_afinfo(afinfo);
766 return err;
767 }
768
769
770 static int stale_bundle(struct dst_entry *dst);
771
772 /* Main function: finds/creates a bundle for given flow.
773 *
774 * At the moment we eat a raw IP route. Mostly to speed up lookups
775 * on interfaces with disabled IPsec.
776 */
777 int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
778 struct sock *sk, int flags)
779 {
780 struct xfrm_policy *policy;
781 struct xfrm_state *xfrm[XFRM_MAX_DEPTH];
782 struct dst_entry *dst, *dst_orig = *dst_p;
783 int nx = 0;
784 int err;
785 u32 genid;
786 u16 family;
787 u8 dir = policy_to_flow_dir(XFRM_POLICY_OUT);
788 u32 sk_sid = security_sk_sid(sk, fl, dir);
789 restart:
790 genid = atomic_read(&flow_cache_genid);
791 policy = NULL;
792 if (sk && sk->sk_policy[1])
793 policy = xfrm_sk_policy_lookup(sk, XFRM_POLICY_OUT, fl, sk_sid);
794
795 if (!policy) {
796 /* To accelerate a bit... */
797 if ((dst_orig->flags & DST_NOXFRM) || !xfrm_policy_list[XFRM_POLICY_OUT])
798 return 0;
799
800 policy = flow_cache_lookup(fl, sk_sid, dst_orig->ops->family,
801 dir, xfrm_policy_lookup);
802 }
803
804 if (!policy)
805 return 0;
806
807 family = dst_orig->ops->family;
808 policy->curlft.use_time = (unsigned long)xtime.tv_sec;
809
810 switch (policy->action) {
811 case XFRM_POLICY_BLOCK:
812 /* Prohibit the flow */
813 err = -EPERM;
814 goto error;
815
816 case XFRM_POLICY_ALLOW:
817 if (policy->xfrm_nr == 0) {
818 /* Flow passes not transformed. */
819 xfrm_pol_put(policy);
820 return 0;
821 }
822
823 /* Try to find matching bundle.
824 *
825 * LATER: help from flow cache. It is optional, this
826 * is required only for output policy.
827 */
828 dst = xfrm_find_bundle(fl, policy, family);
829 if (IS_ERR(dst)) {
830 err = PTR_ERR(dst);
831 goto error;
832 }
833
834 if (dst)
835 break;
836
837 nx = xfrm_tmpl_resolve(policy, fl, xfrm, family);
838
839 if (unlikely(nx<0)) {
840 err = nx;
841 if (err == -EAGAIN && flags) {
842 DECLARE_WAITQUEUE(wait, current);
843
844 add_wait_queue(&km_waitq, &wait);
845 set_current_state(TASK_INTERRUPTIBLE);
846 schedule();
847 set_current_state(TASK_RUNNING);
848 remove_wait_queue(&km_waitq, &wait);
849
850 nx = xfrm_tmpl_resolve(policy, fl, xfrm, family);
851
852 if (nx == -EAGAIN && signal_pending(current)) {
853 err = -ERESTART;
854 goto error;
855 }
856 if (nx == -EAGAIN ||
857 genid != atomic_read(&flow_cache_genid)) {
858 xfrm_pol_put(policy);
859 goto restart;
860 }
861 err = nx;
862 }
863 if (err < 0)
864 goto error;
865 }
866 if (nx == 0) {
867 /* Flow passes not transformed. */
868 xfrm_pol_put(policy);
869 return 0;
870 }
871
872 dst = dst_orig;
873 err = xfrm_bundle_create(policy, xfrm, nx, fl, &dst, family);
874
875 if (unlikely(err)) {
876 int i;
877 for (i=0; i<nx; i++)
878 xfrm_state_put(xfrm[i]);
879 goto error;
880 }
881
882 write_lock_bh(&policy->lock);
883 if (unlikely(policy->dead || stale_bundle(dst))) {
884 /* Wow! While we worked on resolving, this
885 * policy has gone. Retry. It is not paranoia,
886 * we just cannot enlist new bundle to dead object.
887 * We can't enlist stable bundles either.
888 */
889 write_unlock_bh(&policy->lock);
890 if (dst)
891 dst_free(dst);
892
893 err = -EHOSTUNREACH;
894 goto error;
895 }
896 dst->next = policy->bundles;
897 policy->bundles = dst;
898 dst_hold(dst);
899 write_unlock_bh(&policy->lock);
900 }
901 *dst_p = dst;
902 dst_release(dst_orig);
903 xfrm_pol_put(policy);
904 return 0;
905
906 error:
907 dst_release(dst_orig);
908 xfrm_pol_put(policy);
909 *dst_p = NULL;
910 return err;
911 }
912 EXPORT_SYMBOL(xfrm_lookup);
913
914 /* When skb is transformed back to its "native" form, we have to
915 * check policy restrictions. At the moment we make this in maximally
916 * stupid way. Shame on me. :-) Of course, connected sockets must
917 * have policy cached at them.
918 */
919
920 static inline int
921 xfrm_state_ok(struct xfrm_tmpl *tmpl, struct xfrm_state *x,
922 unsigned short family)
923 {
924 if (xfrm_state_kern(x))
925 return tmpl->optional && !xfrm_state_addr_cmp(tmpl, x, family);
926 return x->id.proto == tmpl->id.proto &&
927 (x->id.spi == tmpl->id.spi || !tmpl->id.spi) &&
928 (x->props.reqid == tmpl->reqid || !tmpl->reqid) &&
929 x->props.mode == tmpl->mode &&
930 (tmpl->aalgos & (1<<x->props.aalgo)) &&
931 !(x->props.mode && xfrm_state_addr_cmp(tmpl, x, family));
932 }
933
934 static inline int
935 xfrm_policy_ok(struct xfrm_tmpl *tmpl, struct sec_path *sp, int start,
936 unsigned short family)
937 {
938 int idx = start;
939
940 if (tmpl->optional) {
941 if (!tmpl->mode)
942 return start;
943 } else
944 start = -1;
945 for (; idx < sp->len; idx++) {
946 if (xfrm_state_ok(tmpl, sp->xvec[idx], family))
947 return ++idx;
948 if (sp->xvec[idx]->props.mode)
949 break;
950 }
951 return start;
952 }
953
954 int
955 xfrm_decode_session(struct sk_buff *skb, struct flowi *fl, unsigned short family)
956 {
957 struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
958
959 if (unlikely(afinfo == NULL))
960 return -EAFNOSUPPORT;
961
962 afinfo->decode_session(skb, fl);
963 xfrm_policy_put_afinfo(afinfo);
964 return 0;
965 }
966 EXPORT_SYMBOL(xfrm_decode_session);
967
968 static inline int secpath_has_tunnel(struct sec_path *sp, int k)
969 {
970 for (; k < sp->len; k++) {
971 if (sp->xvec[k]->props.mode)
972 return 1;
973 }
974
975 return 0;
976 }
977
978 int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb,
979 unsigned short family)
980 {
981 struct xfrm_policy *pol;
982 struct flowi fl;
983 u8 fl_dir = policy_to_flow_dir(dir);
984 u32 sk_sid;
985
986 if (xfrm_decode_session(skb, &fl, family) < 0)
987 return 0;
988 nf_nat_decode_session(skb, &fl, family);
989
990 sk_sid = security_sk_sid(sk, &fl, fl_dir);
991
992 /* First, check used SA against their selectors. */
993 if (skb->sp) {
994 int i;
995
996 for (i=skb->sp->len-1; i>=0; i--) {
997 struct xfrm_state *x = skb->sp->xvec[i];
998 if (!xfrm_selector_match(&x->sel, &fl, family))
999 return 0;
1000 }
1001 }
1002
1003 pol = NULL;
1004 if (sk && sk->sk_policy[dir])
1005 pol = xfrm_sk_policy_lookup(sk, dir, &fl, sk_sid);
1006
1007 if (!pol)
1008 pol = flow_cache_lookup(&fl, sk_sid, family, fl_dir,
1009 xfrm_policy_lookup);
1010
1011 if (!pol)
1012 return !skb->sp || !secpath_has_tunnel(skb->sp, 0);
1013
1014 pol->curlft.use_time = (unsigned long)xtime.tv_sec;
1015
1016 if (pol->action == XFRM_POLICY_ALLOW) {
1017 struct sec_path *sp;
1018 static struct sec_path dummy;
1019 int i, k;
1020
1021 if ((sp = skb->sp) == NULL)
1022 sp = &dummy;
1023
1024 /* For each tunnel xfrm, find the first matching tmpl.
1025 * For each tmpl before that, find corresponding xfrm.
1026 * Order is _important_. Later we will implement
1027 * some barriers, but at the moment barriers
1028 * are implied between each two transformations.
1029 */
1030 for (i = pol->xfrm_nr-1, k = 0; i >= 0; i--) {
1031 k = xfrm_policy_ok(pol->xfrm_vec+i, sp, k, family);
1032 if (k < 0)
1033 goto reject;
1034 }
1035
1036 if (secpath_has_tunnel(sp, k))
1037 goto reject;
1038
1039 xfrm_pol_put(pol);
1040 return 1;
1041 }
1042
1043 reject:
1044 xfrm_pol_put(pol);
1045 return 0;
1046 }
1047 EXPORT_SYMBOL(__xfrm_policy_check);
1048
1049 int __xfrm_route_forward(struct sk_buff *skb, unsigned short family)
1050 {
1051 struct flowi fl;
1052
1053 if (xfrm_decode_session(skb, &fl, family) < 0)
1054 return 0;
1055
1056 return xfrm_lookup(&skb->dst, &fl, NULL, 0) == 0;
1057 }
1058 EXPORT_SYMBOL(__xfrm_route_forward);
1059
1060 static struct dst_entry *xfrm_dst_check(struct dst_entry *dst, u32 cookie)
1061 {
1062 /* If it is marked obsolete, which is how we even get here,
1063 * then we have purged it from the policy bundle list and we
1064 * did that for a good reason.
1065 */
1066 return NULL;
1067 }
1068
1069 static int stale_bundle(struct dst_entry *dst)
1070 {
1071 return !xfrm_bundle_ok((struct xfrm_dst *)dst, NULL, AF_UNSPEC);
1072 }
1073
1074 void xfrm_dst_ifdown(struct dst_entry *dst, struct net_device *dev)
1075 {
1076 while ((dst = dst->child) && dst->xfrm && dst->dev == dev) {
1077 dst->dev = &loopback_dev;
1078 dev_hold(&loopback_dev);
1079 dev_put(dev);
1080 }
1081 }
1082 EXPORT_SYMBOL(xfrm_dst_ifdown);
1083
1084 static void xfrm_link_failure(struct sk_buff *skb)
1085 {
1086 /* Impossible. Such dst must be popped before reaches point of failure. */
1087 return;
1088 }
1089
1090 static struct dst_entry *xfrm_negative_advice(struct dst_entry *dst)
1091 {
1092 if (dst) {
1093 if (dst->obsolete) {
1094 dst_release(dst);
1095 dst = NULL;
1096 }
1097 }
1098 return dst;
1099 }
1100
1101 static void xfrm_prune_bundles(int (*func)(struct dst_entry *))
1102 {
1103 int i;
1104 struct xfrm_policy *pol;
1105 struct dst_entry *dst, **dstp, *gc_list = NULL;
1106
1107 read_lock_bh(&xfrm_policy_lock);
1108 for (i=0; i<2*XFRM_POLICY_MAX; i++) {
1109 for (pol = xfrm_policy_list[i]; pol; pol = pol->next) {
1110 write_lock(&pol->lock);
1111 dstp = &pol->bundles;
1112 while ((dst=*dstp) != NULL) {
1113 if (func(dst)) {
1114 *dstp = dst->next;
1115 dst->next = gc_list;
1116 gc_list = dst;
1117 } else {
1118 dstp = &dst->next;
1119 }
1120 }
1121 write_unlock(&pol->lock);
1122 }
1123 }
1124 read_unlock_bh(&xfrm_policy_lock);
1125
1126 while (gc_list) {
1127 dst = gc_list;
1128 gc_list = dst->next;
1129 dst_free(dst);
1130 }
1131 }
1132
1133 static int unused_bundle(struct dst_entry *dst)
1134 {
1135 return !atomic_read(&dst->__refcnt);
1136 }
1137
1138 static void __xfrm_garbage_collect(void)
1139 {
1140 xfrm_prune_bundles(unused_bundle);
1141 }
1142
1143 int xfrm_flush_bundles(void)
1144 {
1145 xfrm_prune_bundles(stale_bundle);
1146 return 0;
1147 }
1148
1149 static int always_true(struct dst_entry *dst)
1150 {
1151 return 1;
1152 }
1153
1154 void xfrm_flush_all_bundles(void)
1155 {
1156 xfrm_prune_bundles(always_true);
1157 }
1158
1159 void xfrm_init_pmtu(struct dst_entry *dst)
1160 {
1161 do {
1162 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
1163 u32 pmtu, route_mtu_cached;
1164
1165 pmtu = dst_mtu(dst->child);
1166 xdst->child_mtu_cached = pmtu;
1167
1168 pmtu = xfrm_state_mtu(dst->xfrm, pmtu);
1169
1170 route_mtu_cached = dst_mtu(xdst->route);
1171 xdst->route_mtu_cached = route_mtu_cached;
1172
1173 if (pmtu > route_mtu_cached)
1174 pmtu = route_mtu_cached;
1175
1176 dst->metrics[RTAX_MTU-1] = pmtu;
1177 } while ((dst = dst->next));
1178 }
1179
1180 EXPORT_SYMBOL(xfrm_init_pmtu);
1181
1182 /* Check that the bundle accepts the flow and its components are
1183 * still valid.
1184 */
1185
1186 int xfrm_bundle_ok(struct xfrm_dst *first, struct flowi *fl, int family)
1187 {
1188 struct dst_entry *dst = &first->u.dst;
1189 struct xfrm_dst *last;
1190 u32 mtu;
1191
1192 if (!dst_check(dst->path, ((struct xfrm_dst *)dst)->path_cookie) ||
1193 (dst->dev && !netif_running(dst->dev)))
1194 return 0;
1195
1196 last = NULL;
1197
1198 do {
1199 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
1200
1201 if (fl && !xfrm_selector_match(&dst->xfrm->sel, fl, family))
1202 return 0;
1203 if (dst->xfrm->km.state != XFRM_STATE_VALID)
1204 return 0;
1205
1206 mtu = dst_mtu(dst->child);
1207 if (xdst->child_mtu_cached != mtu) {
1208 last = xdst;
1209 xdst->child_mtu_cached = mtu;
1210 }
1211
1212 if (!dst_check(xdst->route, xdst->route_cookie))
1213 return 0;
1214 mtu = dst_mtu(xdst->route);
1215 if (xdst->route_mtu_cached != mtu) {
1216 last = xdst;
1217 xdst->route_mtu_cached = mtu;
1218 }
1219
1220 dst = dst->child;
1221 } while (dst->xfrm);
1222
1223 if (likely(!last))
1224 return 1;
1225
1226 mtu = last->child_mtu_cached;
1227 for (;;) {
1228 dst = &last->u.dst;
1229
1230 mtu = xfrm_state_mtu(dst->xfrm, mtu);
1231 if (mtu > last->route_mtu_cached)
1232 mtu = last->route_mtu_cached;
1233 dst->metrics[RTAX_MTU-1] = mtu;
1234
1235 if (last == first)
1236 break;
1237
1238 last = last->u.next;
1239 last->child_mtu_cached = mtu;
1240 }
1241
1242 return 1;
1243 }
1244
1245 EXPORT_SYMBOL(xfrm_bundle_ok);
1246
1247 int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo)
1248 {
1249 int err = 0;
1250 if (unlikely(afinfo == NULL))
1251 return -EINVAL;
1252 if (unlikely(afinfo->family >= NPROTO))
1253 return -EAFNOSUPPORT;
1254 write_lock_bh(&xfrm_policy_afinfo_lock);
1255 if (unlikely(xfrm_policy_afinfo[afinfo->family] != NULL))
1256 err = -ENOBUFS;
1257 else {
1258 struct dst_ops *dst_ops = afinfo->dst_ops;
1259 if (likely(dst_ops->kmem_cachep == NULL))
1260 dst_ops->kmem_cachep = xfrm_dst_cache;
1261 if (likely(dst_ops->check == NULL))
1262 dst_ops->check = xfrm_dst_check;
1263 if (likely(dst_ops->negative_advice == NULL))
1264 dst_ops->negative_advice = xfrm_negative_advice;
1265 if (likely(dst_ops->link_failure == NULL))
1266 dst_ops->link_failure = xfrm_link_failure;
1267 if (likely(afinfo->garbage_collect == NULL))
1268 afinfo->garbage_collect = __xfrm_garbage_collect;
1269 xfrm_policy_afinfo[afinfo->family] = afinfo;
1270 }
1271 write_unlock_bh(&xfrm_policy_afinfo_lock);
1272 return err;
1273 }
1274 EXPORT_SYMBOL(xfrm_policy_register_afinfo);
1275
1276 int xfrm_policy_unregister_afinfo(struct xfrm_policy_afinfo *afinfo)
1277 {
1278 int err = 0;
1279 if (unlikely(afinfo == NULL))
1280 return -EINVAL;
1281 if (unlikely(afinfo->family >= NPROTO))
1282 return -EAFNOSUPPORT;
1283 write_lock_bh(&xfrm_policy_afinfo_lock);
1284 if (likely(xfrm_policy_afinfo[afinfo->family] != NULL)) {
1285 if (unlikely(xfrm_policy_afinfo[afinfo->family] != afinfo))
1286 err = -EINVAL;
1287 else {
1288 struct dst_ops *dst_ops = afinfo->dst_ops;
1289 xfrm_policy_afinfo[afinfo->family] = NULL;
1290 dst_ops->kmem_cachep = NULL;
1291 dst_ops->check = NULL;
1292 dst_ops->negative_advice = NULL;
1293 dst_ops->link_failure = NULL;
1294 afinfo->garbage_collect = NULL;
1295 }
1296 }
1297 write_unlock_bh(&xfrm_policy_afinfo_lock);
1298 return err;
1299 }
1300 EXPORT_SYMBOL(xfrm_policy_unregister_afinfo);
1301
1302 static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family)
1303 {
1304 struct xfrm_policy_afinfo *afinfo;
1305 if (unlikely(family >= NPROTO))
1306 return NULL;
1307 read_lock(&xfrm_policy_afinfo_lock);
1308 afinfo = xfrm_policy_afinfo[family];
1309 if (likely(afinfo != NULL))
1310 read_lock(&afinfo->lock);
1311 read_unlock(&xfrm_policy_afinfo_lock);
1312 return afinfo;
1313 }
1314
1315 static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo)
1316 {
1317 if (unlikely(afinfo == NULL))
1318 return;
1319 read_unlock(&afinfo->lock);
1320 }
1321
1322 static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
1323 {
1324 switch (event) {
1325 case NETDEV_DOWN:
1326 xfrm_flush_bundles();
1327 }
1328 return NOTIFY_DONE;
1329 }
1330
1331 static struct notifier_block xfrm_dev_notifier = {
1332 xfrm_dev_event,
1333 NULL,
1334 0
1335 };
1336
1337 static void __init xfrm_policy_init(void)
1338 {
1339 xfrm_dst_cache = kmem_cache_create("xfrm_dst_cache",
1340 sizeof(struct xfrm_dst),
1341 0, SLAB_HWCACHE_ALIGN,
1342 NULL, NULL);
1343 if (!xfrm_dst_cache)
1344 panic("XFRM: failed to allocate xfrm_dst_cache\n");
1345
1346 INIT_WORK(&xfrm_policy_gc_work, xfrm_policy_gc_task, NULL);
1347 register_netdevice_notifier(&xfrm_dev_notifier);
1348 }
1349
1350 void __init xfrm_init(void)
1351 {
1352 xfrm_state_init();
1353 xfrm_policy_init();
1354 xfrm_input_init();
1355 }
1356
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