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1da177e4 LT |
1 | /* key.c: basic authentication token and access key management |
2 | * | |
3 | * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/module.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/sched.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/workqueue.h> | |
17 | #include <linux/err.h> | |
18 | #include "internal.h" | |
19 | ||
20 | static kmem_cache_t *key_jar; | |
21 | static key_serial_t key_serial_next = 3; | |
22 | struct rb_root key_serial_tree; /* tree of keys indexed by serial */ | |
23 | DEFINE_SPINLOCK(key_serial_lock); | |
24 | ||
25 | struct rb_root key_user_tree; /* tree of quota records indexed by UID */ | |
26 | DEFINE_SPINLOCK(key_user_lock); | |
27 | ||
28 | static LIST_HEAD(key_types_list); | |
29 | static DECLARE_RWSEM(key_types_sem); | |
30 | ||
31 | static void key_cleanup(void *data); | |
32 | static DECLARE_WORK(key_cleanup_task, key_cleanup, NULL); | |
33 | ||
34 | /* we serialise key instantiation and link */ | |
35 | DECLARE_RWSEM(key_construction_sem); | |
36 | ||
37 | /* any key who's type gets unegistered will be re-typed to this */ | |
38 | struct key_type key_type_dead = { | |
39 | .name = "dead", | |
40 | }; | |
41 | ||
42 | #ifdef KEY_DEBUGGING | |
43 | void __key_check(const struct key *key) | |
44 | { | |
45 | printk("__key_check: key %p {%08x} should be {%08x}\n", | |
46 | key, key->magic, KEY_DEBUG_MAGIC); | |
47 | BUG(); | |
48 | } | |
49 | #endif | |
50 | ||
51 | /*****************************************************************************/ | |
52 | /* | |
53 | * get the key quota record for a user, allocating a new record if one doesn't | |
54 | * already exist | |
55 | */ | |
56 | struct key_user *key_user_lookup(uid_t uid) | |
57 | { | |
58 | struct key_user *candidate = NULL, *user; | |
59 | struct rb_node *parent = NULL; | |
60 | struct rb_node **p; | |
61 | ||
62 | try_again: | |
63 | p = &key_user_tree.rb_node; | |
64 | spin_lock(&key_user_lock); | |
65 | ||
66 | /* search the tree for a user record with a matching UID */ | |
67 | while (*p) { | |
68 | parent = *p; | |
69 | user = rb_entry(parent, struct key_user, node); | |
70 | ||
71 | if (uid < user->uid) | |
72 | p = &(*p)->rb_left; | |
73 | else if (uid > user->uid) | |
74 | p = &(*p)->rb_right; | |
75 | else | |
76 | goto found; | |
77 | } | |
78 | ||
79 | /* if we get here, we failed to find a match in the tree */ | |
80 | if (!candidate) { | |
81 | /* allocate a candidate user record if we don't already have | |
82 | * one */ | |
83 | spin_unlock(&key_user_lock); | |
84 | ||
85 | user = NULL; | |
86 | candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL); | |
87 | if (unlikely(!candidate)) | |
88 | goto out; | |
89 | ||
90 | /* the allocation may have scheduled, so we need to repeat the | |
91 | * search lest someone else added the record whilst we were | |
92 | * asleep */ | |
93 | goto try_again; | |
94 | } | |
95 | ||
96 | /* if we get here, then the user record still hadn't appeared on the | |
97 | * second pass - so we use the candidate record */ | |
98 | atomic_set(&candidate->usage, 1); | |
99 | atomic_set(&candidate->nkeys, 0); | |
100 | atomic_set(&candidate->nikeys, 0); | |
101 | candidate->uid = uid; | |
102 | candidate->qnkeys = 0; | |
103 | candidate->qnbytes = 0; | |
104 | spin_lock_init(&candidate->lock); | |
105 | INIT_LIST_HEAD(&candidate->consq); | |
106 | ||
107 | rb_link_node(&candidate->node, parent, p); | |
108 | rb_insert_color(&candidate->node, &key_user_tree); | |
109 | spin_unlock(&key_user_lock); | |
110 | user = candidate; | |
111 | goto out; | |
112 | ||
113 | /* okay - we found a user record for this UID */ | |
114 | found: | |
115 | atomic_inc(&user->usage); | |
116 | spin_unlock(&key_user_lock); | |
117 | if (candidate) | |
118 | kfree(candidate); | |
119 | out: | |
120 | return user; | |
121 | ||
122 | } /* end key_user_lookup() */ | |
123 | ||
124 | /*****************************************************************************/ | |
125 | /* | |
126 | * dispose of a user structure | |
127 | */ | |
128 | void key_user_put(struct key_user *user) | |
129 | { | |
130 | if (atomic_dec_and_lock(&user->usage, &key_user_lock)) { | |
131 | rb_erase(&user->node, &key_user_tree); | |
132 | spin_unlock(&key_user_lock); | |
133 | ||
134 | kfree(user); | |
135 | } | |
136 | ||
137 | } /* end key_user_put() */ | |
138 | ||
139 | /*****************************************************************************/ | |
140 | /* | |
141 | * insert a key with a fixed serial number | |
142 | */ | |
143 | static void __init __key_insert_serial(struct key *key) | |
144 | { | |
145 | struct rb_node *parent, **p; | |
146 | struct key *xkey; | |
147 | ||
148 | parent = NULL; | |
149 | p = &key_serial_tree.rb_node; | |
150 | ||
151 | while (*p) { | |
152 | parent = *p; | |
153 | xkey = rb_entry(parent, struct key, serial_node); | |
154 | ||
155 | if (key->serial < xkey->serial) | |
156 | p = &(*p)->rb_left; | |
157 | else if (key->serial > xkey->serial) | |
158 | p = &(*p)->rb_right; | |
159 | else | |
160 | BUG(); | |
161 | } | |
162 | ||
163 | /* we've found a suitable hole - arrange for this key to occupy it */ | |
164 | rb_link_node(&key->serial_node, parent, p); | |
165 | rb_insert_color(&key->serial_node, &key_serial_tree); | |
166 | ||
167 | } /* end __key_insert_serial() */ | |
168 | ||
169 | /*****************************************************************************/ | |
170 | /* | |
171 | * assign a key the next unique serial number | |
172 | * - we work through all the serial numbers between 2 and 2^31-1 in turn and | |
173 | * then wrap | |
174 | */ | |
175 | static inline void key_alloc_serial(struct key *key) | |
176 | { | |
177 | struct rb_node *parent, **p; | |
178 | struct key *xkey; | |
179 | ||
180 | spin_lock(&key_serial_lock); | |
181 | ||
182 | /* propose a likely serial number and look for a hole for it in the | |
183 | * serial number tree */ | |
184 | key->serial = key_serial_next; | |
185 | if (key->serial < 3) | |
186 | key->serial = 3; | |
187 | key_serial_next = key->serial + 1; | |
188 | ||
189 | parent = NULL; | |
190 | p = &key_serial_tree.rb_node; | |
191 | ||
192 | while (*p) { | |
193 | parent = *p; | |
194 | xkey = rb_entry(parent, struct key, serial_node); | |
195 | ||
196 | if (key->serial < xkey->serial) | |
197 | p = &(*p)->rb_left; | |
198 | else if (key->serial > xkey->serial) | |
199 | p = &(*p)->rb_right; | |
200 | else | |
201 | goto serial_exists; | |
202 | } | |
203 | goto insert_here; | |
204 | ||
205 | /* we found a key with the proposed serial number - walk the tree from | |
206 | * that point looking for the next unused serial number */ | |
207 | serial_exists: | |
208 | for (;;) { | |
209 | key->serial = key_serial_next; | |
210 | if (key->serial < 2) | |
211 | key->serial = 2; | |
212 | key_serial_next = key->serial + 1; | |
213 | ||
214 | if (!parent->rb_parent) | |
215 | p = &key_serial_tree.rb_node; | |
216 | else if (parent->rb_parent->rb_left == parent) | |
217 | p = &parent->rb_parent->rb_left; | |
218 | else | |
219 | p = &parent->rb_parent->rb_right; | |
220 | ||
221 | parent = rb_next(parent); | |
222 | if (!parent) | |
223 | break; | |
224 | ||
225 | xkey = rb_entry(parent, struct key, serial_node); | |
226 | if (key->serial < xkey->serial) | |
227 | goto insert_here; | |
228 | } | |
229 | ||
230 | /* we've found a suitable hole - arrange for this key to occupy it */ | |
231 | insert_here: | |
232 | rb_link_node(&key->serial_node, parent, p); | |
233 | rb_insert_color(&key->serial_node, &key_serial_tree); | |
234 | ||
235 | spin_unlock(&key_serial_lock); | |
236 | ||
237 | } /* end key_alloc_serial() */ | |
238 | ||
239 | /*****************************************************************************/ | |
240 | /* | |
241 | * allocate a key of the specified type | |
242 | * - update the user's quota to reflect the existence of the key | |
243 | * - called from a key-type operation with key_types_sem read-locked by either | |
244 | * key_create_or_update() or by key_duplicate(); this prevents unregistration | |
245 | * of the key type | |
246 | * - upon return the key is as yet uninstantiated; the caller needs to either | |
247 | * instantiate the key or discard it before returning | |
248 | */ | |
249 | struct key *key_alloc(struct key_type *type, const char *desc, | |
250 | uid_t uid, gid_t gid, key_perm_t perm, | |
251 | int not_in_quota) | |
252 | { | |
253 | struct key_user *user = NULL; | |
254 | struct key *key; | |
255 | size_t desclen, quotalen; | |
256 | ||
257 | key = ERR_PTR(-EINVAL); | |
258 | if (!desc || !*desc) | |
259 | goto error; | |
260 | ||
261 | desclen = strlen(desc) + 1; | |
262 | quotalen = desclen + type->def_datalen; | |
263 | ||
264 | /* get hold of the key tracking for this user */ | |
265 | user = key_user_lookup(uid); | |
266 | if (!user) | |
267 | goto no_memory_1; | |
268 | ||
269 | /* check that the user's quota permits allocation of another key and | |
270 | * its description */ | |
271 | if (!not_in_quota) { | |
272 | spin_lock(&user->lock); | |
273 | if (user->qnkeys + 1 >= KEYQUOTA_MAX_KEYS && | |
274 | user->qnbytes + quotalen >= KEYQUOTA_MAX_BYTES | |
275 | ) | |
276 | goto no_quota; | |
277 | ||
278 | user->qnkeys++; | |
279 | user->qnbytes += quotalen; | |
280 | spin_unlock(&user->lock); | |
281 | } | |
282 | ||
283 | /* allocate and initialise the key and its description */ | |
284 | key = kmem_cache_alloc(key_jar, SLAB_KERNEL); | |
285 | if (!key) | |
286 | goto no_memory_2; | |
287 | ||
288 | if (desc) { | |
289 | key->description = kmalloc(desclen, GFP_KERNEL); | |
290 | if (!key->description) | |
291 | goto no_memory_3; | |
292 | ||
293 | memcpy(key->description, desc, desclen); | |
294 | } | |
295 | ||
296 | atomic_set(&key->usage, 1); | |
1da177e4 LT |
297 | init_rwsem(&key->sem); |
298 | key->type = type; | |
299 | key->user = user; | |
300 | key->quotalen = quotalen; | |
301 | key->datalen = type->def_datalen; | |
302 | key->uid = uid; | |
303 | key->gid = gid; | |
304 | key->perm = perm; | |
305 | key->flags = 0; | |
306 | key->expiry = 0; | |
307 | key->payload.data = NULL; | |
308 | ||
309 | if (!not_in_quota) | |
76d8aeab | 310 | key->flags |= 1 << KEY_FLAG_IN_QUOTA; |
1da177e4 LT |
311 | |
312 | memset(&key->type_data, 0, sizeof(key->type_data)); | |
313 | ||
314 | #ifdef KEY_DEBUGGING | |
315 | key->magic = KEY_DEBUG_MAGIC; | |
316 | #endif | |
317 | ||
318 | /* publish the key by giving it a serial number */ | |
319 | atomic_inc(&user->nkeys); | |
320 | key_alloc_serial(key); | |
321 | ||
322 | error: | |
323 | return key; | |
324 | ||
325 | no_memory_3: | |
326 | kmem_cache_free(key_jar, key); | |
327 | no_memory_2: | |
328 | if (!not_in_quota) { | |
329 | spin_lock(&user->lock); | |
330 | user->qnkeys--; | |
331 | user->qnbytes -= quotalen; | |
332 | spin_unlock(&user->lock); | |
333 | } | |
334 | key_user_put(user); | |
335 | no_memory_1: | |
336 | key = ERR_PTR(-ENOMEM); | |
337 | goto error; | |
338 | ||
339 | no_quota: | |
340 | spin_unlock(&user->lock); | |
341 | key_user_put(user); | |
342 | key = ERR_PTR(-EDQUOT); | |
343 | goto error; | |
344 | ||
345 | } /* end key_alloc() */ | |
346 | ||
347 | EXPORT_SYMBOL(key_alloc); | |
348 | ||
349 | /*****************************************************************************/ | |
350 | /* | |
351 | * reserve an amount of quota for the key's payload | |
352 | */ | |
353 | int key_payload_reserve(struct key *key, size_t datalen) | |
354 | { | |
355 | int delta = (int) datalen - key->datalen; | |
356 | int ret = 0; | |
357 | ||
358 | key_check(key); | |
359 | ||
360 | /* contemplate the quota adjustment */ | |
76d8aeab | 361 | if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { |
1da177e4 LT |
362 | spin_lock(&key->user->lock); |
363 | ||
364 | if (delta > 0 && | |
365 | key->user->qnbytes + delta > KEYQUOTA_MAX_BYTES | |
366 | ) { | |
367 | ret = -EDQUOT; | |
368 | } | |
369 | else { | |
370 | key->user->qnbytes += delta; | |
371 | key->quotalen += delta; | |
372 | } | |
373 | spin_unlock(&key->user->lock); | |
374 | } | |
375 | ||
376 | /* change the recorded data length if that didn't generate an error */ | |
377 | if (ret == 0) | |
378 | key->datalen = datalen; | |
379 | ||
380 | return ret; | |
381 | ||
382 | } /* end key_payload_reserve() */ | |
383 | ||
384 | EXPORT_SYMBOL(key_payload_reserve); | |
385 | ||
386 | /*****************************************************************************/ | |
387 | /* | |
388 | * instantiate a key and link it into the target keyring atomically | |
389 | * - called with the target keyring's semaphore writelocked | |
390 | */ | |
391 | static int __key_instantiate_and_link(struct key *key, | |
392 | const void *data, | |
393 | size_t datalen, | |
394 | struct key *keyring) | |
395 | { | |
396 | int ret, awaken; | |
397 | ||
398 | key_check(key); | |
399 | key_check(keyring); | |
400 | ||
401 | awaken = 0; | |
402 | ret = -EBUSY; | |
403 | ||
404 | down_write(&key_construction_sem); | |
405 | ||
406 | /* can't instantiate twice */ | |
76d8aeab | 407 | if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { |
1da177e4 LT |
408 | /* instantiate the key */ |
409 | ret = key->type->instantiate(key, data, datalen); | |
410 | ||
411 | if (ret == 0) { | |
412 | /* mark the key as being instantiated */ | |
1da177e4 | 413 | atomic_inc(&key->user->nikeys); |
76d8aeab | 414 | set_bit(KEY_FLAG_INSTANTIATED, &key->flags); |
1da177e4 | 415 | |
76d8aeab | 416 | if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) |
1da177e4 | 417 | awaken = 1; |
1da177e4 LT |
418 | |
419 | /* and link it into the destination keyring */ | |
420 | if (keyring) | |
421 | ret = __key_link(keyring, key); | |
422 | } | |
423 | } | |
424 | ||
425 | up_write(&key_construction_sem); | |
426 | ||
427 | /* wake up anyone waiting for a key to be constructed */ | |
428 | if (awaken) | |
429 | wake_up_all(&request_key_conswq); | |
430 | ||
431 | return ret; | |
432 | ||
433 | } /* end __key_instantiate_and_link() */ | |
434 | ||
435 | /*****************************************************************************/ | |
436 | /* | |
437 | * instantiate a key and link it into the target keyring atomically | |
438 | */ | |
439 | int key_instantiate_and_link(struct key *key, | |
440 | const void *data, | |
441 | size_t datalen, | |
442 | struct key *keyring) | |
443 | { | |
444 | int ret; | |
445 | ||
446 | if (keyring) | |
447 | down_write(&keyring->sem); | |
448 | ||
449 | ret = __key_instantiate_and_link(key, data, datalen, keyring); | |
450 | ||
451 | if (keyring) | |
452 | up_write(&keyring->sem); | |
453 | ||
454 | return ret; | |
455 | } /* end key_instantiate_and_link() */ | |
456 | ||
457 | EXPORT_SYMBOL(key_instantiate_and_link); | |
458 | ||
459 | /*****************************************************************************/ | |
460 | /* | |
461 | * negatively instantiate a key and link it into the target keyring atomically | |
462 | */ | |
463 | int key_negate_and_link(struct key *key, | |
464 | unsigned timeout, | |
465 | struct key *keyring) | |
466 | { | |
467 | struct timespec now; | |
468 | int ret, awaken; | |
469 | ||
470 | key_check(key); | |
471 | key_check(keyring); | |
472 | ||
473 | awaken = 0; | |
474 | ret = -EBUSY; | |
475 | ||
476 | if (keyring) | |
477 | down_write(&keyring->sem); | |
478 | ||
479 | down_write(&key_construction_sem); | |
480 | ||
481 | /* can't instantiate twice */ | |
76d8aeab | 482 | if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { |
1da177e4 | 483 | /* mark the key as being negatively instantiated */ |
1da177e4 | 484 | atomic_inc(&key->user->nikeys); |
76d8aeab DH |
485 | set_bit(KEY_FLAG_NEGATIVE, &key->flags); |
486 | set_bit(KEY_FLAG_INSTANTIATED, &key->flags); | |
1da177e4 LT |
487 | now = current_kernel_time(); |
488 | key->expiry = now.tv_sec + timeout; | |
489 | ||
76d8aeab | 490 | if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) |
1da177e4 | 491 | awaken = 1; |
1da177e4 | 492 | |
1da177e4 LT |
493 | ret = 0; |
494 | ||
495 | /* and link it into the destination keyring */ | |
496 | if (keyring) | |
497 | ret = __key_link(keyring, key); | |
498 | } | |
499 | ||
500 | up_write(&key_construction_sem); | |
501 | ||
502 | if (keyring) | |
503 | up_write(&keyring->sem); | |
504 | ||
505 | /* wake up anyone waiting for a key to be constructed */ | |
506 | if (awaken) | |
507 | wake_up_all(&request_key_conswq); | |
508 | ||
509 | return ret; | |
510 | ||
511 | } /* end key_negate_and_link() */ | |
512 | ||
513 | EXPORT_SYMBOL(key_negate_and_link); | |
514 | ||
515 | /*****************************************************************************/ | |
516 | /* | |
517 | * do cleaning up in process context so that we don't have to disable | |
518 | * interrupts all over the place | |
519 | */ | |
520 | static void key_cleanup(void *data) | |
521 | { | |
522 | struct rb_node *_n; | |
523 | struct key *key; | |
524 | ||
525 | go_again: | |
526 | /* look for a dead key in the tree */ | |
527 | spin_lock(&key_serial_lock); | |
528 | ||
529 | for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { | |
530 | key = rb_entry(_n, struct key, serial_node); | |
531 | ||
532 | if (atomic_read(&key->usage) == 0) | |
533 | goto found_dead_key; | |
534 | } | |
535 | ||
536 | spin_unlock(&key_serial_lock); | |
537 | return; | |
538 | ||
539 | found_dead_key: | |
540 | /* we found a dead key - once we've removed it from the tree, we can | |
541 | * drop the lock */ | |
542 | rb_erase(&key->serial_node, &key_serial_tree); | |
543 | spin_unlock(&key_serial_lock); | |
544 | ||
76d8aeab DH |
545 | key_check(key); |
546 | ||
1da177e4 | 547 | /* deal with the user's key tracking and quota */ |
76d8aeab | 548 | if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { |
1da177e4 LT |
549 | spin_lock(&key->user->lock); |
550 | key->user->qnkeys--; | |
551 | key->user->qnbytes -= key->quotalen; | |
552 | spin_unlock(&key->user->lock); | |
553 | } | |
554 | ||
555 | atomic_dec(&key->user->nkeys); | |
76d8aeab | 556 | if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) |
1da177e4 LT |
557 | atomic_dec(&key->user->nikeys); |
558 | ||
559 | key_user_put(key->user); | |
560 | ||
561 | /* now throw away the key memory */ | |
562 | if (key->type->destroy) | |
563 | key->type->destroy(key); | |
564 | ||
565 | kfree(key->description); | |
566 | ||
567 | #ifdef KEY_DEBUGGING | |
568 | key->magic = KEY_DEBUG_MAGIC_X; | |
569 | #endif | |
570 | kmem_cache_free(key_jar, key); | |
571 | ||
572 | /* there may, of course, be more than one key to destroy */ | |
573 | goto go_again; | |
574 | ||
575 | } /* end key_cleanup() */ | |
576 | ||
577 | /*****************************************************************************/ | |
578 | /* | |
579 | * dispose of a reference to a key | |
580 | * - when all the references are gone, we schedule the cleanup task to come and | |
581 | * pull it out of the tree in definite process context | |
582 | */ | |
583 | void key_put(struct key *key) | |
584 | { | |
585 | if (key) { | |
586 | key_check(key); | |
587 | ||
588 | if (atomic_dec_and_test(&key->usage)) | |
589 | schedule_work(&key_cleanup_task); | |
590 | } | |
591 | ||
592 | } /* end key_put() */ | |
593 | ||
594 | EXPORT_SYMBOL(key_put); | |
595 | ||
596 | /*****************************************************************************/ | |
597 | /* | |
598 | * find a key by its serial number | |
599 | */ | |
600 | struct key *key_lookup(key_serial_t id) | |
601 | { | |
602 | struct rb_node *n; | |
603 | struct key *key; | |
604 | ||
605 | spin_lock(&key_serial_lock); | |
606 | ||
607 | /* search the tree for the specified key */ | |
608 | n = key_serial_tree.rb_node; | |
609 | while (n) { | |
610 | key = rb_entry(n, struct key, serial_node); | |
611 | ||
612 | if (id < key->serial) | |
613 | n = n->rb_left; | |
614 | else if (id > key->serial) | |
615 | n = n->rb_right; | |
616 | else | |
617 | goto found; | |
618 | } | |
619 | ||
620 | not_found: | |
621 | key = ERR_PTR(-ENOKEY); | |
622 | goto error; | |
623 | ||
624 | found: | |
76d8aeab | 625 | /* pretend it doesn't exist if it's dead */ |
1da177e4 | 626 | if (atomic_read(&key->usage) == 0 || |
76d8aeab | 627 | test_bit(KEY_FLAG_DEAD, &key->flags) || |
1da177e4 LT |
628 | key->type == &key_type_dead) |
629 | goto not_found; | |
630 | ||
631 | /* this races with key_put(), but that doesn't matter since key_put() | |
632 | * doesn't actually change the key | |
633 | */ | |
634 | atomic_inc(&key->usage); | |
635 | ||
636 | error: | |
637 | spin_unlock(&key_serial_lock); | |
638 | return key; | |
639 | ||
640 | } /* end key_lookup() */ | |
641 | ||
642 | /*****************************************************************************/ | |
643 | /* | |
644 | * find and lock the specified key type against removal | |
645 | * - we return with the sem readlocked | |
646 | */ | |
647 | struct key_type *key_type_lookup(const char *type) | |
648 | { | |
649 | struct key_type *ktype; | |
650 | ||
651 | down_read(&key_types_sem); | |
652 | ||
653 | /* look up the key type to see if it's one of the registered kernel | |
654 | * types */ | |
655 | list_for_each_entry(ktype, &key_types_list, link) { | |
656 | if (strcmp(ktype->name, type) == 0) | |
657 | goto found_kernel_type; | |
658 | } | |
659 | ||
660 | up_read(&key_types_sem); | |
661 | ktype = ERR_PTR(-ENOKEY); | |
662 | ||
663 | found_kernel_type: | |
664 | return ktype; | |
665 | ||
666 | } /* end key_type_lookup() */ | |
667 | ||
668 | /*****************************************************************************/ | |
669 | /* | |
670 | * unlock a key type | |
671 | */ | |
672 | void key_type_put(struct key_type *ktype) | |
673 | { | |
674 | up_read(&key_types_sem); | |
675 | ||
676 | } /* end key_type_put() */ | |
677 | ||
678 | /*****************************************************************************/ | |
679 | /* | |
680 | * attempt to update an existing key | |
681 | * - the key has an incremented refcount | |
682 | * - we need to put the key if we get an error | |
683 | */ | |
684 | static inline struct key *__key_update(struct key *key, const void *payload, | |
685 | size_t plen) | |
686 | { | |
687 | int ret; | |
688 | ||
689 | /* need write permission on the key to update it */ | |
690 | ret = -EACCES; | |
691 | if (!key_permission(key, KEY_WRITE)) | |
692 | goto error; | |
693 | ||
694 | ret = -EEXIST; | |
695 | if (!key->type->update) | |
696 | goto error; | |
697 | ||
698 | down_write(&key->sem); | |
699 | ||
700 | ret = key->type->update(key, payload, plen); | |
701 | ||
76d8aeab | 702 | if (ret == 0) |
1da177e4 | 703 | /* updating a negative key instantiates it */ |
76d8aeab | 704 | clear_bit(KEY_FLAG_NEGATIVE, &key->flags); |
1da177e4 LT |
705 | |
706 | up_write(&key->sem); | |
707 | ||
708 | if (ret < 0) | |
709 | goto error; | |
710 | out: | |
711 | return key; | |
712 | ||
713 | error: | |
714 | key_put(key); | |
715 | key = ERR_PTR(ret); | |
716 | goto out; | |
717 | ||
718 | } /* end __key_update() */ | |
719 | ||
720 | /*****************************************************************************/ | |
721 | /* | |
722 | * search the specified keyring for a key of the same description; if one is | |
723 | * found, update it, otherwise add a new one | |
724 | */ | |
725 | struct key *key_create_or_update(struct key *keyring, | |
726 | const char *type, | |
727 | const char *description, | |
728 | const void *payload, | |
729 | size_t plen, | |
730 | int not_in_quota) | |
731 | { | |
732 | struct key_type *ktype; | |
733 | struct key *key = NULL; | |
734 | key_perm_t perm; | |
735 | int ret; | |
736 | ||
737 | key_check(keyring); | |
738 | ||
739 | /* look up the key type to see if it's one of the registered kernel | |
740 | * types */ | |
741 | ktype = key_type_lookup(type); | |
742 | if (IS_ERR(ktype)) { | |
743 | key = ERR_PTR(-ENODEV); | |
744 | goto error; | |
745 | } | |
746 | ||
747 | ret = -EINVAL; | |
748 | if (!ktype->match || !ktype->instantiate) | |
749 | goto error_2; | |
750 | ||
751 | /* search for an existing key of the same type and description in the | |
752 | * destination keyring | |
753 | */ | |
754 | down_write(&keyring->sem); | |
755 | ||
756 | key = __keyring_search_one(keyring, ktype, description, 0); | |
757 | if (!IS_ERR(key)) | |
758 | goto found_matching_key; | |
759 | ||
760 | /* if we're going to allocate a new key, we're going to have to modify | |
761 | * the keyring */ | |
762 | ret = -EACCES; | |
763 | if (!key_permission(keyring, KEY_WRITE)) | |
764 | goto error_3; | |
765 | ||
766 | /* decide on the permissions we want */ | |
767 | perm = KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK; | |
768 | ||
769 | if (ktype->read) | |
770 | perm |= KEY_USR_READ; | |
771 | ||
772 | if (ktype == &key_type_keyring || ktype->update) | |
773 | perm |= KEY_USR_WRITE; | |
774 | ||
775 | /* allocate a new key */ | |
776 | key = key_alloc(ktype, description, current->fsuid, current->fsgid, | |
777 | perm, not_in_quota); | |
778 | if (IS_ERR(key)) { | |
779 | ret = PTR_ERR(key); | |
780 | goto error_3; | |
781 | } | |
782 | ||
783 | /* instantiate it and link it into the target keyring */ | |
784 | ret = __key_instantiate_and_link(key, payload, plen, keyring); | |
785 | if (ret < 0) { | |
786 | key_put(key); | |
787 | key = ERR_PTR(ret); | |
788 | } | |
789 | ||
790 | error_3: | |
791 | up_write(&keyring->sem); | |
792 | error_2: | |
793 | key_type_put(ktype); | |
794 | error: | |
795 | return key; | |
796 | ||
797 | found_matching_key: | |
798 | /* we found a matching key, so we're going to try to update it | |
799 | * - we can drop the locks first as we have the key pinned | |
800 | */ | |
801 | up_write(&keyring->sem); | |
802 | key_type_put(ktype); | |
803 | ||
804 | key = __key_update(key, payload, plen); | |
805 | goto error; | |
806 | ||
807 | } /* end key_create_or_update() */ | |
808 | ||
809 | EXPORT_SYMBOL(key_create_or_update); | |
810 | ||
811 | /*****************************************************************************/ | |
812 | /* | |
813 | * update a key | |
814 | */ | |
815 | int key_update(struct key *key, const void *payload, size_t plen) | |
816 | { | |
817 | int ret; | |
818 | ||
819 | key_check(key); | |
820 | ||
821 | /* the key must be writable */ | |
822 | ret = -EACCES; | |
823 | if (!key_permission(key, KEY_WRITE)) | |
824 | goto error; | |
825 | ||
826 | /* attempt to update it if supported */ | |
827 | ret = -EOPNOTSUPP; | |
828 | if (key->type->update) { | |
829 | down_write(&key->sem); | |
830 | ret = key->type->update(key, payload, plen); | |
831 | ||
76d8aeab | 832 | if (ret == 0) |
1da177e4 | 833 | /* updating a negative key instantiates it */ |
76d8aeab | 834 | clear_bit(KEY_FLAG_NEGATIVE, &key->flags); |
1da177e4 LT |
835 | |
836 | up_write(&key->sem); | |
837 | } | |
838 | ||
839 | error: | |
840 | return ret; | |
841 | ||
842 | } /* end key_update() */ | |
843 | ||
844 | EXPORT_SYMBOL(key_update); | |
845 | ||
846 | /*****************************************************************************/ | |
847 | /* | |
848 | * duplicate a key, potentially with a revised description | |
849 | * - must be supported by the keytype (keyrings for instance can be duplicated) | |
850 | */ | |
851 | struct key *key_duplicate(struct key *source, const char *desc) | |
852 | { | |
853 | struct key *key; | |
854 | int ret; | |
855 | ||
856 | key_check(source); | |
857 | ||
858 | if (!desc) | |
859 | desc = source->description; | |
860 | ||
861 | down_read(&key_types_sem); | |
862 | ||
863 | ret = -EINVAL; | |
864 | if (!source->type->duplicate) | |
865 | goto error; | |
866 | ||
867 | /* allocate and instantiate a key */ | |
868 | key = key_alloc(source->type, desc, current->fsuid, current->fsgid, | |
869 | source->perm, 0); | |
870 | if (IS_ERR(key)) | |
871 | goto error_k; | |
872 | ||
873 | down_read(&source->sem); | |
874 | ret = key->type->duplicate(key, source); | |
875 | up_read(&source->sem); | |
876 | if (ret < 0) | |
877 | goto error2; | |
878 | ||
879 | atomic_inc(&key->user->nikeys); | |
76d8aeab | 880 | set_bit(KEY_FLAG_INSTANTIATED, &key->flags); |
1da177e4 LT |
881 | |
882 | error_k: | |
883 | up_read(&key_types_sem); | |
884 | out: | |
885 | return key; | |
886 | ||
887 | error2: | |
888 | key_put(key); | |
889 | error: | |
890 | up_read(&key_types_sem); | |
891 | key = ERR_PTR(ret); | |
892 | goto out; | |
893 | ||
894 | } /* end key_duplicate() */ | |
895 | ||
896 | /*****************************************************************************/ | |
897 | /* | |
898 | * revoke a key | |
899 | */ | |
900 | void key_revoke(struct key *key) | |
901 | { | |
902 | key_check(key); | |
903 | ||
904 | /* make sure no one's trying to change or use the key when we mark | |
905 | * it */ | |
906 | down_write(&key->sem); | |
76d8aeab | 907 | set_bit(KEY_FLAG_REVOKED, &key->flags); |
1da177e4 LT |
908 | up_write(&key->sem); |
909 | ||
910 | } /* end key_revoke() */ | |
911 | ||
912 | EXPORT_SYMBOL(key_revoke); | |
913 | ||
914 | /*****************************************************************************/ | |
915 | /* | |
916 | * register a type of key | |
917 | */ | |
918 | int register_key_type(struct key_type *ktype) | |
919 | { | |
920 | struct key_type *p; | |
921 | int ret; | |
922 | ||
923 | ret = -EEXIST; | |
924 | down_write(&key_types_sem); | |
925 | ||
926 | /* disallow key types with the same name */ | |
927 | list_for_each_entry(p, &key_types_list, link) { | |
928 | if (strcmp(p->name, ktype->name) == 0) | |
929 | goto out; | |
930 | } | |
931 | ||
932 | /* store the type */ | |
933 | list_add(&ktype->link, &key_types_list); | |
934 | ret = 0; | |
935 | ||
936 | out: | |
937 | up_write(&key_types_sem); | |
938 | return ret; | |
939 | ||
940 | } /* end register_key_type() */ | |
941 | ||
942 | EXPORT_SYMBOL(register_key_type); | |
943 | ||
944 | /*****************************************************************************/ | |
945 | /* | |
946 | * unregister a type of key | |
947 | */ | |
948 | void unregister_key_type(struct key_type *ktype) | |
949 | { | |
950 | struct rb_node *_n; | |
951 | struct key *key; | |
952 | ||
953 | down_write(&key_types_sem); | |
954 | ||
955 | /* withdraw the key type */ | |
956 | list_del_init(&ktype->link); | |
957 | ||
76d8aeab | 958 | /* mark all the keys of this type dead */ |
1da177e4 LT |
959 | spin_lock(&key_serial_lock); |
960 | ||
961 | for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { | |
962 | key = rb_entry(_n, struct key, serial_node); | |
963 | ||
76d8aeab DH |
964 | if (key->type == ktype) |
965 | key->type = &key_type_dead; | |
966 | } | |
967 | ||
968 | spin_unlock(&key_serial_lock); | |
969 | ||
970 | /* make sure everyone revalidates their keys */ | |
971 | synchronize_kernel(); | |
972 | ||
973 | /* we should now be able to destroy the payloads of all the keys of | |
974 | * this type with impunity */ | |
975 | spin_lock(&key_serial_lock); | |
1da177e4 | 976 | |
76d8aeab DH |
977 | for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { |
978 | key = rb_entry(_n, struct key, serial_node); | |
1da177e4 | 979 | |
76d8aeab DH |
980 | if (key->type == ktype) { |
981 | if (ktype->destroy) | |
982 | ktype->destroy(key); | |
983 | memset(&key->payload, 0xbd, sizeof(key->payload)); | |
984 | } | |
1da177e4 LT |
985 | } |
986 | ||
987 | spin_unlock(&key_serial_lock); | |
988 | up_write(&key_types_sem); | |
989 | ||
990 | } /* end unregister_key_type() */ | |
991 | ||
992 | EXPORT_SYMBOL(unregister_key_type); | |
993 | ||
994 | /*****************************************************************************/ | |
995 | /* | |
996 | * initialise the key management stuff | |
997 | */ | |
998 | void __init key_init(void) | |
999 | { | |
1000 | /* allocate a slab in which we can store keys */ | |
1001 | key_jar = kmem_cache_create("key_jar", sizeof(struct key), | |
1002 | 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1003 | ||
1004 | /* add the special key types */ | |
1005 | list_add_tail(&key_type_keyring.link, &key_types_list); | |
1006 | list_add_tail(&key_type_dead.link, &key_types_list); | |
1007 | list_add_tail(&key_type_user.link, &key_types_list); | |
1008 | ||
1009 | /* record the root user tracking */ | |
1010 | rb_link_node(&root_key_user.node, | |
1011 | NULL, | |
1012 | &key_user_tree.rb_node); | |
1013 | ||
1014 | rb_insert_color(&root_key_user.node, | |
1015 | &key_user_tree); | |
1016 | ||
1017 | /* record root's user standard keyrings */ | |
1018 | key_check(&root_user_keyring); | |
1019 | key_check(&root_session_keyring); | |
1020 | ||
1021 | __key_insert_serial(&root_user_keyring); | |
1022 | __key_insert_serial(&root_session_keyring); | |
1023 | ||
1024 | keyring_publish_name(&root_user_keyring); | |
1025 | keyring_publish_name(&root_session_keyring); | |
1026 | ||
1027 | /* link the two root keyrings together */ | |
1028 | key_link(&root_session_keyring, &root_user_keyring); | |
76d8aeab | 1029 | |
1da177e4 | 1030 | } /* end key_init() */ |