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1da177e4 LT |
1 | /* key.c: basic authentication token and access key management |
2 | * | |
3dccff8d | 3 | * Copyright (C) 2004-6 Red Hat, Inc. All Rights Reserved. |
1da177e4 LT |
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> | |
a7807a32 | 14 | #include <linux/poison.h> |
1da177e4 LT |
15 | #include <linux/sched.h> |
16 | #include <linux/slab.h> | |
29db9190 | 17 | #include <linux/security.h> |
1da177e4 | 18 | #include <linux/workqueue.h> |
e51f6d34 | 19 | #include <linux/random.h> |
1da177e4 LT |
20 | #include <linux/err.h> |
21 | #include "internal.h" | |
22 | ||
e18b890b | 23 | static struct kmem_cache *key_jar; |
1da177e4 LT |
24 | struct rb_root key_serial_tree; /* tree of keys indexed by serial */ |
25 | DEFINE_SPINLOCK(key_serial_lock); | |
26 | ||
27 | struct rb_root key_user_tree; /* tree of quota records indexed by UID */ | |
28 | DEFINE_SPINLOCK(key_user_lock); | |
29 | ||
30 | static LIST_HEAD(key_types_list); | |
31 | static DECLARE_RWSEM(key_types_sem); | |
32 | ||
65f27f38 DH |
33 | static void key_cleanup(struct work_struct *work); |
34 | static DECLARE_WORK(key_cleanup_task, key_cleanup); | |
1da177e4 LT |
35 | |
36 | /* we serialise key instantiation and link */ | |
37 | DECLARE_RWSEM(key_construction_sem); | |
38 | ||
39 | /* any key who's type gets unegistered will be re-typed to this */ | |
1ae8f407 | 40 | static struct key_type key_type_dead = { |
1da177e4 LT |
41 | .name = "dead", |
42 | }; | |
43 | ||
44 | #ifdef KEY_DEBUGGING | |
45 | void __key_check(const struct key *key) | |
46 | { | |
47 | printk("__key_check: key %p {%08x} should be {%08x}\n", | |
48 | key, key->magic, KEY_DEBUG_MAGIC); | |
49 | BUG(); | |
50 | } | |
51 | #endif | |
52 | ||
53 | /*****************************************************************************/ | |
54 | /* | |
55 | * get the key quota record for a user, allocating a new record if one doesn't | |
56 | * already exist | |
57 | */ | |
58 | struct key_user *key_user_lookup(uid_t uid) | |
59 | { | |
60 | struct key_user *candidate = NULL, *user; | |
61 | struct rb_node *parent = NULL; | |
62 | struct rb_node **p; | |
63 | ||
64 | try_again: | |
65 | p = &key_user_tree.rb_node; | |
66 | spin_lock(&key_user_lock); | |
67 | ||
68 | /* search the tree for a user record with a matching UID */ | |
69 | while (*p) { | |
70 | parent = *p; | |
71 | user = rb_entry(parent, struct key_user, node); | |
72 | ||
73 | if (uid < user->uid) | |
74 | p = &(*p)->rb_left; | |
75 | else if (uid > user->uid) | |
76 | p = &(*p)->rb_right; | |
77 | else | |
78 | goto found; | |
79 | } | |
80 | ||
81 | /* if we get here, we failed to find a match in the tree */ | |
82 | if (!candidate) { | |
83 | /* allocate a candidate user record if we don't already have | |
84 | * one */ | |
85 | spin_unlock(&key_user_lock); | |
86 | ||
87 | user = NULL; | |
88 | candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL); | |
89 | if (unlikely(!candidate)) | |
90 | goto out; | |
91 | ||
92 | /* the allocation may have scheduled, so we need to repeat the | |
93 | * search lest someone else added the record whilst we were | |
94 | * asleep */ | |
95 | goto try_again; | |
96 | } | |
97 | ||
98 | /* if we get here, then the user record still hadn't appeared on the | |
99 | * second pass - so we use the candidate record */ | |
100 | atomic_set(&candidate->usage, 1); | |
101 | atomic_set(&candidate->nkeys, 0); | |
102 | atomic_set(&candidate->nikeys, 0); | |
103 | candidate->uid = uid; | |
104 | candidate->qnkeys = 0; | |
105 | candidate->qnbytes = 0; | |
106 | spin_lock_init(&candidate->lock); | |
107 | INIT_LIST_HEAD(&candidate->consq); | |
108 | ||
109 | rb_link_node(&candidate->node, parent, p); | |
110 | rb_insert_color(&candidate->node, &key_user_tree); | |
111 | spin_unlock(&key_user_lock); | |
112 | user = candidate; | |
113 | goto out; | |
114 | ||
115 | /* okay - we found a user record for this UID */ | |
116 | found: | |
117 | atomic_inc(&user->usage); | |
118 | spin_unlock(&key_user_lock); | |
a7f988ba | 119 | kfree(candidate); |
1da177e4 LT |
120 | out: |
121 | return user; | |
122 | ||
123 | } /* end key_user_lookup() */ | |
124 | ||
125 | /*****************************************************************************/ | |
126 | /* | |
127 | * dispose of a user structure | |
128 | */ | |
129 | void key_user_put(struct key_user *user) | |
130 | { | |
131 | if (atomic_dec_and_lock(&user->usage, &key_user_lock)) { | |
132 | rb_erase(&user->node, &key_user_tree); | |
133 | spin_unlock(&key_user_lock); | |
134 | ||
135 | kfree(user); | |
136 | } | |
137 | ||
138 | } /* end key_user_put() */ | |
139 | ||
140 | /*****************************************************************************/ | |
141 | /* | |
142 | * insert a key with a fixed serial number | |
143 | */ | |
144 | static void __init __key_insert_serial(struct key *key) | |
145 | { | |
146 | struct rb_node *parent, **p; | |
147 | struct key *xkey; | |
148 | ||
149 | parent = NULL; | |
150 | p = &key_serial_tree.rb_node; | |
151 | ||
152 | while (*p) { | |
153 | parent = *p; | |
154 | xkey = rb_entry(parent, struct key, serial_node); | |
155 | ||
156 | if (key->serial < xkey->serial) | |
157 | p = &(*p)->rb_left; | |
158 | else if (key->serial > xkey->serial) | |
159 | p = &(*p)->rb_right; | |
160 | else | |
161 | BUG(); | |
162 | } | |
163 | ||
164 | /* we've found a suitable hole - arrange for this key to occupy it */ | |
165 | rb_link_node(&key->serial_node, parent, p); | |
166 | rb_insert_color(&key->serial_node, &key_serial_tree); | |
167 | ||
168 | } /* end __key_insert_serial() */ | |
169 | ||
170 | /*****************************************************************************/ | |
171 | /* | |
172 | * assign a key the next unique serial number | |
e51f6d34 ML |
173 | * - these are assigned randomly to avoid security issues through covert |
174 | * channel problems | |
1da177e4 LT |
175 | */ |
176 | static inline void key_alloc_serial(struct key *key) | |
177 | { | |
178 | struct rb_node *parent, **p; | |
179 | struct key *xkey; | |
180 | ||
e51f6d34 | 181 | /* propose a random serial number and look for a hole for it in the |
1da177e4 | 182 | * serial number tree */ |
e51f6d34 ML |
183 | do { |
184 | get_random_bytes(&key->serial, sizeof(key->serial)); | |
185 | ||
186 | key->serial >>= 1; /* negative numbers are not permitted */ | |
187 | } while (key->serial < 3); | |
188 | ||
189 | spin_lock(&key_serial_lock); | |
1da177e4 LT |
190 | |
191 | parent = NULL; | |
192 | p = &key_serial_tree.rb_node; | |
193 | ||
194 | while (*p) { | |
195 | parent = *p; | |
196 | xkey = rb_entry(parent, struct key, serial_node); | |
197 | ||
198 | if (key->serial < xkey->serial) | |
199 | p = &(*p)->rb_left; | |
200 | else if (key->serial > xkey->serial) | |
201 | p = &(*p)->rb_right; | |
202 | else | |
203 | goto serial_exists; | |
204 | } | |
205 | goto insert_here; | |
206 | ||
207 | /* we found a key with the proposed serial number - walk the tree from | |
208 | * that point looking for the next unused serial number */ | |
e51f6d34 | 209 | serial_exists: |
1da177e4 | 210 | for (;;) { |
e51f6d34 | 211 | key->serial++; |
1da177e4 LT |
212 | if (key->serial < 2) |
213 | key->serial = 2; | |
1da177e4 | 214 | |
fed306f2 | 215 | if (!rb_parent(parent)) |
1da177e4 | 216 | p = &key_serial_tree.rb_node; |
fed306f2 DW |
217 | else if (rb_parent(parent)->rb_left == parent) |
218 | p = &(rb_parent(parent)->rb_left); | |
1da177e4 | 219 | else |
fed306f2 | 220 | p = &(rb_parent(parent)->rb_right); |
1da177e4 LT |
221 | |
222 | parent = rb_next(parent); | |
223 | if (!parent) | |
224 | break; | |
225 | ||
226 | xkey = rb_entry(parent, struct key, serial_node); | |
227 | if (key->serial < xkey->serial) | |
228 | goto insert_here; | |
229 | } | |
230 | ||
231 | /* we've found a suitable hole - arrange for this key to occupy it */ | |
e51f6d34 | 232 | insert_here: |
1da177e4 LT |
233 | rb_link_node(&key->serial_node, parent, p); |
234 | rb_insert_color(&key->serial_node, &key_serial_tree); | |
235 | ||
236 | spin_unlock(&key_serial_lock); | |
237 | ||
238 | } /* end key_alloc_serial() */ | |
239 | ||
240 | /*****************************************************************************/ | |
241 | /* | |
242 | * allocate a key of the specified type | |
243 | * - update the user's quota to reflect the existence of the key | |
8d9067bd DH |
244 | * - called from a key-type operation with key_types_sem read-locked by |
245 | * key_create_or_update() | |
246 | * - this prevents unregistration of the key type | |
1da177e4 LT |
247 | * - upon return the key is as yet uninstantiated; the caller needs to either |
248 | * instantiate the key or discard it before returning | |
249 | */ | |
250 | struct key *key_alloc(struct key_type *type, const char *desc, | |
d720024e | 251 | uid_t uid, gid_t gid, struct task_struct *ctx, |
7e047ef5 | 252 | key_perm_t perm, unsigned long flags) |
1da177e4 LT |
253 | { |
254 | struct key_user *user = NULL; | |
255 | struct key *key; | |
256 | size_t desclen, quotalen; | |
29db9190 | 257 | int ret; |
1da177e4 LT |
258 | |
259 | key = ERR_PTR(-EINVAL); | |
260 | if (!desc || !*desc) | |
261 | goto error; | |
262 | ||
263 | desclen = strlen(desc) + 1; | |
264 | quotalen = desclen + type->def_datalen; | |
265 | ||
266 | /* get hold of the key tracking for this user */ | |
267 | user = key_user_lookup(uid); | |
268 | if (!user) | |
269 | goto no_memory_1; | |
270 | ||
271 | /* check that the user's quota permits allocation of another key and | |
272 | * its description */ | |
7e047ef5 | 273 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
1da177e4 | 274 | spin_lock(&user->lock); |
7e047ef5 DH |
275 | if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) { |
276 | if (user->qnkeys + 1 >= KEYQUOTA_MAX_KEYS || | |
277 | user->qnbytes + quotalen >= KEYQUOTA_MAX_BYTES | |
278 | ) | |
279 | goto no_quota; | |
280 | } | |
1da177e4 LT |
281 | |
282 | user->qnkeys++; | |
283 | user->qnbytes += quotalen; | |
284 | spin_unlock(&user->lock); | |
285 | } | |
286 | ||
287 | /* allocate and initialise the key and its description */ | |
e94b1766 | 288 | key = kmem_cache_alloc(key_jar, GFP_KERNEL); |
1da177e4 LT |
289 | if (!key) |
290 | goto no_memory_2; | |
291 | ||
292 | if (desc) { | |
293 | key->description = kmalloc(desclen, GFP_KERNEL); | |
294 | if (!key->description) | |
295 | goto no_memory_3; | |
296 | ||
297 | memcpy(key->description, desc, desclen); | |
298 | } | |
299 | ||
300 | atomic_set(&key->usage, 1); | |
1da177e4 LT |
301 | init_rwsem(&key->sem); |
302 | key->type = type; | |
303 | key->user = user; | |
304 | key->quotalen = quotalen; | |
305 | key->datalen = type->def_datalen; | |
306 | key->uid = uid; | |
307 | key->gid = gid; | |
308 | key->perm = perm; | |
309 | key->flags = 0; | |
310 | key->expiry = 0; | |
311 | key->payload.data = NULL; | |
29db9190 | 312 | key->security = NULL; |
1da177e4 | 313 | |
7e047ef5 | 314 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) |
76d8aeab | 315 | key->flags |= 1 << KEY_FLAG_IN_QUOTA; |
1da177e4 LT |
316 | |
317 | memset(&key->type_data, 0, sizeof(key->type_data)); | |
318 | ||
319 | #ifdef KEY_DEBUGGING | |
320 | key->magic = KEY_DEBUG_MAGIC; | |
321 | #endif | |
322 | ||
29db9190 | 323 | /* let the security module know about the key */ |
7e047ef5 | 324 | ret = security_key_alloc(key, ctx, flags); |
29db9190 DH |
325 | if (ret < 0) |
326 | goto security_error; | |
327 | ||
1da177e4 LT |
328 | /* publish the key by giving it a serial number */ |
329 | atomic_inc(&user->nkeys); | |
330 | key_alloc_serial(key); | |
331 | ||
29db9190 | 332 | error: |
1da177e4 LT |
333 | return key; |
334 | ||
29db9190 DH |
335 | security_error: |
336 | kfree(key->description); | |
1da177e4 | 337 | kmem_cache_free(key_jar, key); |
7e047ef5 | 338 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
1da177e4 LT |
339 | spin_lock(&user->lock); |
340 | user->qnkeys--; | |
341 | user->qnbytes -= quotalen; | |
342 | spin_unlock(&user->lock); | |
343 | } | |
344 | key_user_put(user); | |
29db9190 DH |
345 | key = ERR_PTR(ret); |
346 | goto error; | |
347 | ||
348 | no_memory_3: | |
349 | kmem_cache_free(key_jar, key); | |
350 | no_memory_2: | |
7e047ef5 | 351 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
29db9190 DH |
352 | spin_lock(&user->lock); |
353 | user->qnkeys--; | |
354 | user->qnbytes -= quotalen; | |
355 | spin_unlock(&user->lock); | |
356 | } | |
357 | key_user_put(user); | |
358 | no_memory_1: | |
1da177e4 LT |
359 | key = ERR_PTR(-ENOMEM); |
360 | goto error; | |
361 | ||
29db9190 | 362 | no_quota: |
1da177e4 LT |
363 | spin_unlock(&user->lock); |
364 | key_user_put(user); | |
365 | key = ERR_PTR(-EDQUOT); | |
366 | goto error; | |
367 | ||
368 | } /* end key_alloc() */ | |
369 | ||
370 | EXPORT_SYMBOL(key_alloc); | |
371 | ||
372 | /*****************************************************************************/ | |
373 | /* | |
374 | * reserve an amount of quota for the key's payload | |
375 | */ | |
376 | int key_payload_reserve(struct key *key, size_t datalen) | |
377 | { | |
378 | int delta = (int) datalen - key->datalen; | |
379 | int ret = 0; | |
380 | ||
381 | key_check(key); | |
382 | ||
383 | /* contemplate the quota adjustment */ | |
76d8aeab | 384 | if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { |
1da177e4 LT |
385 | spin_lock(&key->user->lock); |
386 | ||
387 | if (delta > 0 && | |
388 | key->user->qnbytes + delta > KEYQUOTA_MAX_BYTES | |
389 | ) { | |
390 | ret = -EDQUOT; | |
391 | } | |
392 | else { | |
393 | key->user->qnbytes += delta; | |
394 | key->quotalen += delta; | |
395 | } | |
396 | spin_unlock(&key->user->lock); | |
397 | } | |
398 | ||
399 | /* change the recorded data length if that didn't generate an error */ | |
400 | if (ret == 0) | |
401 | key->datalen = datalen; | |
402 | ||
403 | return ret; | |
404 | ||
405 | } /* end key_payload_reserve() */ | |
406 | ||
407 | EXPORT_SYMBOL(key_payload_reserve); | |
408 | ||
409 | /*****************************************************************************/ | |
410 | /* | |
411 | * instantiate a key and link it into the target keyring atomically | |
412 | * - called with the target keyring's semaphore writelocked | |
413 | */ | |
414 | static int __key_instantiate_and_link(struct key *key, | |
415 | const void *data, | |
416 | size_t datalen, | |
3e30148c DH |
417 | struct key *keyring, |
418 | struct key *instkey) | |
1da177e4 LT |
419 | { |
420 | int ret, awaken; | |
421 | ||
422 | key_check(key); | |
423 | key_check(keyring); | |
424 | ||
425 | awaken = 0; | |
426 | ret = -EBUSY; | |
427 | ||
428 | down_write(&key_construction_sem); | |
429 | ||
430 | /* can't instantiate twice */ | |
76d8aeab | 431 | if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { |
1da177e4 LT |
432 | /* instantiate the key */ |
433 | ret = key->type->instantiate(key, data, datalen); | |
434 | ||
435 | if (ret == 0) { | |
436 | /* mark the key as being instantiated */ | |
1da177e4 | 437 | atomic_inc(&key->user->nikeys); |
76d8aeab | 438 | set_bit(KEY_FLAG_INSTANTIATED, &key->flags); |
1da177e4 | 439 | |
76d8aeab | 440 | if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) |
1da177e4 | 441 | awaken = 1; |
1da177e4 LT |
442 | |
443 | /* and link it into the destination keyring */ | |
444 | if (keyring) | |
445 | ret = __key_link(keyring, key); | |
3e30148c DH |
446 | |
447 | /* disable the authorisation key */ | |
448 | if (instkey) | |
449 | key_revoke(instkey); | |
1da177e4 LT |
450 | } |
451 | } | |
452 | ||
453 | up_write(&key_construction_sem); | |
454 | ||
455 | /* wake up anyone waiting for a key to be constructed */ | |
456 | if (awaken) | |
457 | wake_up_all(&request_key_conswq); | |
458 | ||
459 | return ret; | |
460 | ||
461 | } /* end __key_instantiate_and_link() */ | |
462 | ||
463 | /*****************************************************************************/ | |
464 | /* | |
465 | * instantiate a key and link it into the target keyring atomically | |
466 | */ | |
467 | int key_instantiate_and_link(struct key *key, | |
468 | const void *data, | |
469 | size_t datalen, | |
3e30148c DH |
470 | struct key *keyring, |
471 | struct key *instkey) | |
1da177e4 LT |
472 | { |
473 | int ret; | |
474 | ||
475 | if (keyring) | |
476 | down_write(&keyring->sem); | |
477 | ||
3e30148c | 478 | ret = __key_instantiate_and_link(key, data, datalen, keyring, instkey); |
1da177e4 LT |
479 | |
480 | if (keyring) | |
481 | up_write(&keyring->sem); | |
482 | ||
483 | return ret; | |
3e30148c | 484 | |
1da177e4 LT |
485 | } /* end key_instantiate_and_link() */ |
486 | ||
487 | EXPORT_SYMBOL(key_instantiate_and_link); | |
488 | ||
489 | /*****************************************************************************/ | |
490 | /* | |
491 | * negatively instantiate a key and link it into the target keyring atomically | |
492 | */ | |
493 | int key_negate_and_link(struct key *key, | |
494 | unsigned timeout, | |
3e30148c DH |
495 | struct key *keyring, |
496 | struct key *instkey) | |
1da177e4 LT |
497 | { |
498 | struct timespec now; | |
499 | int ret, awaken; | |
500 | ||
501 | key_check(key); | |
502 | key_check(keyring); | |
503 | ||
504 | awaken = 0; | |
505 | ret = -EBUSY; | |
506 | ||
507 | if (keyring) | |
508 | down_write(&keyring->sem); | |
509 | ||
510 | down_write(&key_construction_sem); | |
511 | ||
512 | /* can't instantiate twice */ | |
76d8aeab | 513 | if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { |
1da177e4 | 514 | /* mark the key as being negatively instantiated */ |
1da177e4 | 515 | atomic_inc(&key->user->nikeys); |
76d8aeab DH |
516 | set_bit(KEY_FLAG_NEGATIVE, &key->flags); |
517 | set_bit(KEY_FLAG_INSTANTIATED, &key->flags); | |
1da177e4 LT |
518 | now = current_kernel_time(); |
519 | key->expiry = now.tv_sec + timeout; | |
520 | ||
76d8aeab | 521 | if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) |
1da177e4 | 522 | awaken = 1; |
1da177e4 | 523 | |
1da177e4 LT |
524 | ret = 0; |
525 | ||
526 | /* and link it into the destination keyring */ | |
527 | if (keyring) | |
528 | ret = __key_link(keyring, key); | |
3e30148c DH |
529 | |
530 | /* disable the authorisation key */ | |
531 | if (instkey) | |
532 | key_revoke(instkey); | |
1da177e4 LT |
533 | } |
534 | ||
535 | up_write(&key_construction_sem); | |
536 | ||
537 | if (keyring) | |
538 | up_write(&keyring->sem); | |
539 | ||
540 | /* wake up anyone waiting for a key to be constructed */ | |
541 | if (awaken) | |
542 | wake_up_all(&request_key_conswq); | |
543 | ||
544 | return ret; | |
545 | ||
546 | } /* end key_negate_and_link() */ | |
547 | ||
548 | EXPORT_SYMBOL(key_negate_and_link); | |
549 | ||
550 | /*****************************************************************************/ | |
551 | /* | |
552 | * do cleaning up in process context so that we don't have to disable | |
553 | * interrupts all over the place | |
554 | */ | |
65f27f38 | 555 | static void key_cleanup(struct work_struct *work) |
1da177e4 LT |
556 | { |
557 | struct rb_node *_n; | |
558 | struct key *key; | |
559 | ||
560 | go_again: | |
561 | /* look for a dead key in the tree */ | |
562 | spin_lock(&key_serial_lock); | |
563 | ||
564 | for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { | |
565 | key = rb_entry(_n, struct key, serial_node); | |
566 | ||
567 | if (atomic_read(&key->usage) == 0) | |
568 | goto found_dead_key; | |
569 | } | |
570 | ||
571 | spin_unlock(&key_serial_lock); | |
572 | return; | |
573 | ||
574 | found_dead_key: | |
575 | /* we found a dead key - once we've removed it from the tree, we can | |
576 | * drop the lock */ | |
577 | rb_erase(&key->serial_node, &key_serial_tree); | |
578 | spin_unlock(&key_serial_lock); | |
579 | ||
76d8aeab DH |
580 | key_check(key); |
581 | ||
29db9190 DH |
582 | security_key_free(key); |
583 | ||
1da177e4 | 584 | /* deal with the user's key tracking and quota */ |
76d8aeab | 585 | if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { |
1da177e4 LT |
586 | spin_lock(&key->user->lock); |
587 | key->user->qnkeys--; | |
588 | key->user->qnbytes -= key->quotalen; | |
589 | spin_unlock(&key->user->lock); | |
590 | } | |
591 | ||
592 | atomic_dec(&key->user->nkeys); | |
76d8aeab | 593 | if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) |
1da177e4 LT |
594 | atomic_dec(&key->user->nikeys); |
595 | ||
596 | key_user_put(key->user); | |
597 | ||
598 | /* now throw away the key memory */ | |
599 | if (key->type->destroy) | |
600 | key->type->destroy(key); | |
601 | ||
602 | kfree(key->description); | |
603 | ||
604 | #ifdef KEY_DEBUGGING | |
605 | key->magic = KEY_DEBUG_MAGIC_X; | |
606 | #endif | |
607 | kmem_cache_free(key_jar, key); | |
608 | ||
609 | /* there may, of course, be more than one key to destroy */ | |
610 | goto go_again; | |
611 | ||
612 | } /* end key_cleanup() */ | |
613 | ||
614 | /*****************************************************************************/ | |
615 | /* | |
616 | * dispose of a reference to a key | |
617 | * - when all the references are gone, we schedule the cleanup task to come and | |
618 | * pull it out of the tree in definite process context | |
619 | */ | |
620 | void key_put(struct key *key) | |
621 | { | |
622 | if (key) { | |
623 | key_check(key); | |
624 | ||
625 | if (atomic_dec_and_test(&key->usage)) | |
626 | schedule_work(&key_cleanup_task); | |
627 | } | |
628 | ||
629 | } /* end key_put() */ | |
630 | ||
631 | EXPORT_SYMBOL(key_put); | |
632 | ||
633 | /*****************************************************************************/ | |
634 | /* | |
635 | * find a key by its serial number | |
636 | */ | |
637 | struct key *key_lookup(key_serial_t id) | |
638 | { | |
639 | struct rb_node *n; | |
640 | struct key *key; | |
641 | ||
642 | spin_lock(&key_serial_lock); | |
643 | ||
644 | /* search the tree for the specified key */ | |
645 | n = key_serial_tree.rb_node; | |
646 | while (n) { | |
647 | key = rb_entry(n, struct key, serial_node); | |
648 | ||
649 | if (id < key->serial) | |
650 | n = n->rb_left; | |
651 | else if (id > key->serial) | |
652 | n = n->rb_right; | |
653 | else | |
654 | goto found; | |
655 | } | |
656 | ||
657 | not_found: | |
658 | key = ERR_PTR(-ENOKEY); | |
659 | goto error; | |
660 | ||
661 | found: | |
76d8aeab | 662 | /* pretend it doesn't exist if it's dead */ |
1da177e4 | 663 | if (atomic_read(&key->usage) == 0 || |
76d8aeab | 664 | test_bit(KEY_FLAG_DEAD, &key->flags) || |
1da177e4 LT |
665 | key->type == &key_type_dead) |
666 | goto not_found; | |
667 | ||
668 | /* this races with key_put(), but that doesn't matter since key_put() | |
669 | * doesn't actually change the key | |
670 | */ | |
671 | atomic_inc(&key->usage); | |
672 | ||
673 | error: | |
674 | spin_unlock(&key_serial_lock); | |
675 | return key; | |
676 | ||
677 | } /* end key_lookup() */ | |
678 | ||
679 | /*****************************************************************************/ | |
680 | /* | |
681 | * find and lock the specified key type against removal | |
682 | * - we return with the sem readlocked | |
683 | */ | |
684 | struct key_type *key_type_lookup(const char *type) | |
685 | { | |
686 | struct key_type *ktype; | |
687 | ||
688 | down_read(&key_types_sem); | |
689 | ||
690 | /* look up the key type to see if it's one of the registered kernel | |
691 | * types */ | |
692 | list_for_each_entry(ktype, &key_types_list, link) { | |
693 | if (strcmp(ktype->name, type) == 0) | |
694 | goto found_kernel_type; | |
695 | } | |
696 | ||
697 | up_read(&key_types_sem); | |
698 | ktype = ERR_PTR(-ENOKEY); | |
699 | ||
700 | found_kernel_type: | |
701 | return ktype; | |
702 | ||
703 | } /* end key_type_lookup() */ | |
704 | ||
705 | /*****************************************************************************/ | |
706 | /* | |
707 | * unlock a key type | |
708 | */ | |
709 | void key_type_put(struct key_type *ktype) | |
710 | { | |
711 | up_read(&key_types_sem); | |
712 | ||
713 | } /* end key_type_put() */ | |
714 | ||
715 | /*****************************************************************************/ | |
716 | /* | |
717 | * attempt to update an existing key | |
718 | * - the key has an incremented refcount | |
719 | * - we need to put the key if we get an error | |
720 | */ | |
664cceb0 DH |
721 | static inline key_ref_t __key_update(key_ref_t key_ref, |
722 | const void *payload, size_t plen) | |
1da177e4 | 723 | { |
664cceb0 | 724 | struct key *key = key_ref_to_ptr(key_ref); |
1da177e4 LT |
725 | int ret; |
726 | ||
727 | /* need write permission on the key to update it */ | |
29db9190 DH |
728 | ret = key_permission(key_ref, KEY_WRITE); |
729 | if (ret < 0) | |
1da177e4 LT |
730 | goto error; |
731 | ||
732 | ret = -EEXIST; | |
733 | if (!key->type->update) | |
734 | goto error; | |
735 | ||
736 | down_write(&key->sem); | |
737 | ||
738 | ret = key->type->update(key, payload, plen); | |
76d8aeab | 739 | if (ret == 0) |
1da177e4 | 740 | /* updating a negative key instantiates it */ |
76d8aeab | 741 | clear_bit(KEY_FLAG_NEGATIVE, &key->flags); |
1da177e4 LT |
742 | |
743 | up_write(&key->sem); | |
744 | ||
745 | if (ret < 0) | |
746 | goto error; | |
664cceb0 DH |
747 | out: |
748 | return key_ref; | |
1da177e4 | 749 | |
664cceb0 | 750 | error: |
1da177e4 | 751 | key_put(key); |
664cceb0 | 752 | key_ref = ERR_PTR(ret); |
1da177e4 LT |
753 | goto out; |
754 | ||
755 | } /* end __key_update() */ | |
756 | ||
757 | /*****************************************************************************/ | |
758 | /* | |
759 | * search the specified keyring for a key of the same description; if one is | |
760 | * found, update it, otherwise add a new one | |
761 | */ | |
664cceb0 DH |
762 | key_ref_t key_create_or_update(key_ref_t keyring_ref, |
763 | const char *type, | |
764 | const char *description, | |
765 | const void *payload, | |
766 | size_t plen, | |
7e047ef5 | 767 | unsigned long flags) |
1da177e4 LT |
768 | { |
769 | struct key_type *ktype; | |
664cceb0 | 770 | struct key *keyring, *key = NULL; |
1da177e4 | 771 | key_perm_t perm; |
664cceb0 | 772 | key_ref_t key_ref; |
1da177e4 LT |
773 | int ret; |
774 | ||
1da177e4 LT |
775 | /* look up the key type to see if it's one of the registered kernel |
776 | * types */ | |
777 | ktype = key_type_lookup(type); | |
778 | if (IS_ERR(ktype)) { | |
664cceb0 | 779 | key_ref = ERR_PTR(-ENODEV); |
1da177e4 LT |
780 | goto error; |
781 | } | |
782 | ||
664cceb0 | 783 | key_ref = ERR_PTR(-EINVAL); |
1da177e4 LT |
784 | if (!ktype->match || !ktype->instantiate) |
785 | goto error_2; | |
786 | ||
664cceb0 DH |
787 | keyring = key_ref_to_ptr(keyring_ref); |
788 | ||
789 | key_check(keyring); | |
790 | ||
c3a9d654 DH |
791 | key_ref = ERR_PTR(-ENOTDIR); |
792 | if (keyring->type != &key_type_keyring) | |
793 | goto error_2; | |
794 | ||
664cceb0 DH |
795 | down_write(&keyring->sem); |
796 | ||
797 | /* if we're going to allocate a new key, we're going to have | |
798 | * to modify the keyring */ | |
29db9190 DH |
799 | ret = key_permission(keyring_ref, KEY_WRITE); |
800 | if (ret < 0) { | |
801 | key_ref = ERR_PTR(ret); | |
664cceb0 | 802 | goto error_3; |
29db9190 | 803 | } |
664cceb0 | 804 | |
1d9b7d97 DH |
805 | /* if it's possible to update this type of key, search for an existing |
806 | * key of the same type and description in the destination keyring and | |
807 | * update that instead if possible | |
1da177e4 | 808 | */ |
1d9b7d97 DH |
809 | if (ktype->update) { |
810 | key_ref = __keyring_search_one(keyring_ref, ktype, description, | |
811 | 0); | |
812 | if (!IS_ERR(key_ref)) | |
813 | goto found_matching_key; | |
814 | } | |
1da177e4 | 815 | |
1da177e4 | 816 | /* decide on the permissions we want */ |
29db9190 DH |
817 | perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR; |
818 | perm |= KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK | KEY_USR_SETATTR; | |
1da177e4 LT |
819 | |
820 | if (ktype->read) | |
664cceb0 | 821 | perm |= KEY_POS_READ | KEY_USR_READ; |
1da177e4 LT |
822 | |
823 | if (ktype == &key_type_keyring || ktype->update) | |
824 | perm |= KEY_USR_WRITE; | |
825 | ||
826 | /* allocate a new key */ | |
827 | key = key_alloc(ktype, description, current->fsuid, current->fsgid, | |
7e047ef5 | 828 | current, perm, flags); |
1da177e4 | 829 | if (IS_ERR(key)) { |
664cceb0 | 830 | key_ref = ERR_PTR(PTR_ERR(key)); |
1da177e4 LT |
831 | goto error_3; |
832 | } | |
833 | ||
834 | /* instantiate it and link it into the target keyring */ | |
3e30148c | 835 | ret = __key_instantiate_and_link(key, payload, plen, keyring, NULL); |
1da177e4 LT |
836 | if (ret < 0) { |
837 | key_put(key); | |
664cceb0 DH |
838 | key_ref = ERR_PTR(ret); |
839 | goto error_3; | |
1da177e4 LT |
840 | } |
841 | ||
664cceb0 DH |
842 | key_ref = make_key_ref(key, is_key_possessed(keyring_ref)); |
843 | ||
1da177e4 LT |
844 | error_3: |
845 | up_write(&keyring->sem); | |
846 | error_2: | |
847 | key_type_put(ktype); | |
848 | error: | |
664cceb0 | 849 | return key_ref; |
1da177e4 LT |
850 | |
851 | found_matching_key: | |
852 | /* we found a matching key, so we're going to try to update it | |
853 | * - we can drop the locks first as we have the key pinned | |
854 | */ | |
855 | up_write(&keyring->sem); | |
856 | key_type_put(ktype); | |
857 | ||
664cceb0 | 858 | key_ref = __key_update(key_ref, payload, plen); |
1da177e4 LT |
859 | goto error; |
860 | ||
861 | } /* end key_create_or_update() */ | |
862 | ||
863 | EXPORT_SYMBOL(key_create_or_update); | |
864 | ||
865 | /*****************************************************************************/ | |
866 | /* | |
867 | * update a key | |
868 | */ | |
664cceb0 | 869 | int key_update(key_ref_t key_ref, const void *payload, size_t plen) |
1da177e4 | 870 | { |
664cceb0 | 871 | struct key *key = key_ref_to_ptr(key_ref); |
1da177e4 LT |
872 | int ret; |
873 | ||
874 | key_check(key); | |
875 | ||
876 | /* the key must be writable */ | |
29db9190 DH |
877 | ret = key_permission(key_ref, KEY_WRITE); |
878 | if (ret < 0) | |
1da177e4 LT |
879 | goto error; |
880 | ||
881 | /* attempt to update it if supported */ | |
882 | ret = -EOPNOTSUPP; | |
883 | if (key->type->update) { | |
884 | down_write(&key->sem); | |
1da177e4 | 885 | |
29db9190 | 886 | ret = key->type->update(key, payload, plen); |
76d8aeab | 887 | if (ret == 0) |
1da177e4 | 888 | /* updating a negative key instantiates it */ |
76d8aeab | 889 | clear_bit(KEY_FLAG_NEGATIVE, &key->flags); |
1da177e4 LT |
890 | |
891 | up_write(&key->sem); | |
892 | } | |
893 | ||
894 | error: | |
895 | return ret; | |
896 | ||
897 | } /* end key_update() */ | |
898 | ||
899 | EXPORT_SYMBOL(key_update); | |
900 | ||
1da177e4 LT |
901 | /*****************************************************************************/ |
902 | /* | |
903 | * revoke a key | |
904 | */ | |
905 | void key_revoke(struct key *key) | |
906 | { | |
907 | key_check(key); | |
908 | ||
909 | /* make sure no one's trying to change or use the key when we mark | |
910 | * it */ | |
911 | down_write(&key->sem); | |
76d8aeab | 912 | set_bit(KEY_FLAG_REVOKED, &key->flags); |
04c567d9 DH |
913 | |
914 | if (key->type->revoke) | |
915 | key->type->revoke(key); | |
916 | ||
1da177e4 LT |
917 | up_write(&key->sem); |
918 | ||
919 | } /* end key_revoke() */ | |
920 | ||
921 | EXPORT_SYMBOL(key_revoke); | |
922 | ||
923 | /*****************************************************************************/ | |
924 | /* | |
925 | * register a type of key | |
926 | */ | |
927 | int register_key_type(struct key_type *ktype) | |
928 | { | |
929 | struct key_type *p; | |
930 | int ret; | |
931 | ||
932 | ret = -EEXIST; | |
933 | down_write(&key_types_sem); | |
934 | ||
935 | /* disallow key types with the same name */ | |
936 | list_for_each_entry(p, &key_types_list, link) { | |
937 | if (strcmp(p->name, ktype->name) == 0) | |
938 | goto out; | |
939 | } | |
940 | ||
941 | /* store the type */ | |
942 | list_add(&ktype->link, &key_types_list); | |
943 | ret = 0; | |
944 | ||
945 | out: | |
946 | up_write(&key_types_sem); | |
947 | return ret; | |
948 | ||
949 | } /* end register_key_type() */ | |
950 | ||
951 | EXPORT_SYMBOL(register_key_type); | |
952 | ||
953 | /*****************************************************************************/ | |
954 | /* | |
955 | * unregister a type of key | |
956 | */ | |
957 | void unregister_key_type(struct key_type *ktype) | |
958 | { | |
959 | struct rb_node *_n; | |
960 | struct key *key; | |
961 | ||
962 | down_write(&key_types_sem); | |
963 | ||
964 | /* withdraw the key type */ | |
965 | list_del_init(&ktype->link); | |
966 | ||
76d8aeab | 967 | /* mark all the keys of this type dead */ |
1da177e4 LT |
968 | spin_lock(&key_serial_lock); |
969 | ||
970 | for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { | |
971 | key = rb_entry(_n, struct key, serial_node); | |
972 | ||
76d8aeab DH |
973 | if (key->type == ktype) |
974 | key->type = &key_type_dead; | |
975 | } | |
976 | ||
977 | spin_unlock(&key_serial_lock); | |
978 | ||
979 | /* make sure everyone revalidates their keys */ | |
b2b18660 | 980 | synchronize_rcu(); |
76d8aeab DH |
981 | |
982 | /* we should now be able to destroy the payloads of all the keys of | |
983 | * this type with impunity */ | |
984 | spin_lock(&key_serial_lock); | |
1da177e4 | 985 | |
76d8aeab DH |
986 | for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { |
987 | key = rb_entry(_n, struct key, serial_node); | |
1da177e4 | 988 | |
76d8aeab DH |
989 | if (key->type == ktype) { |
990 | if (ktype->destroy) | |
991 | ktype->destroy(key); | |
a7807a32 | 992 | memset(&key->payload, KEY_DESTROY, sizeof(key->payload)); |
76d8aeab | 993 | } |
1da177e4 LT |
994 | } |
995 | ||
996 | spin_unlock(&key_serial_lock); | |
997 | up_write(&key_types_sem); | |
998 | ||
999 | } /* end unregister_key_type() */ | |
1000 | ||
1001 | EXPORT_SYMBOL(unregister_key_type); | |
1002 | ||
1003 | /*****************************************************************************/ | |
1004 | /* | |
1005 | * initialise the key management stuff | |
1006 | */ | |
1007 | void __init key_init(void) | |
1008 | { | |
1009 | /* allocate a slab in which we can store keys */ | |
1010 | key_jar = kmem_cache_create("key_jar", sizeof(struct key), | |
1011 | 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1012 | ||
1013 | /* add the special key types */ | |
1014 | list_add_tail(&key_type_keyring.link, &key_types_list); | |
1015 | list_add_tail(&key_type_dead.link, &key_types_list); | |
1016 | list_add_tail(&key_type_user.link, &key_types_list); | |
1017 | ||
1018 | /* record the root user tracking */ | |
1019 | rb_link_node(&root_key_user.node, | |
1020 | NULL, | |
1021 | &key_user_tree.rb_node); | |
1022 | ||
1023 | rb_insert_color(&root_key_user.node, | |
1024 | &key_user_tree); | |
1025 | ||
1026 | /* record root's user standard keyrings */ | |
1027 | key_check(&root_user_keyring); | |
1028 | key_check(&root_session_keyring); | |
1029 | ||
1030 | __key_insert_serial(&root_user_keyring); | |
1031 | __key_insert_serial(&root_session_keyring); | |
1032 | ||
1033 | keyring_publish_name(&root_user_keyring); | |
1034 | keyring_publish_name(&root_session_keyring); | |
1035 | ||
1036 | /* link the two root keyrings together */ | |
1037 | key_link(&root_session_keyring, &root_user_keyring); | |
76d8aeab | 1038 | |
1da177e4 | 1039 | } /* end key_init() */ |