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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) { | |
48ad504e | 293 | key->description = kmemdup(desc, desclen, GFP_KERNEL); |
1da177e4 LT |
294 | if (!key->description) |
295 | goto no_memory_3; | |
1da177e4 LT |
296 | } |
297 | ||
298 | atomic_set(&key->usage, 1); | |
1da177e4 LT |
299 | init_rwsem(&key->sem); |
300 | key->type = type; | |
301 | key->user = user; | |
302 | key->quotalen = quotalen; | |
303 | key->datalen = type->def_datalen; | |
304 | key->uid = uid; | |
305 | key->gid = gid; | |
306 | key->perm = perm; | |
307 | key->flags = 0; | |
308 | key->expiry = 0; | |
309 | key->payload.data = NULL; | |
29db9190 | 310 | key->security = NULL; |
1da177e4 | 311 | |
7e047ef5 | 312 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) |
76d8aeab | 313 | key->flags |= 1 << KEY_FLAG_IN_QUOTA; |
1da177e4 LT |
314 | |
315 | memset(&key->type_data, 0, sizeof(key->type_data)); | |
316 | ||
317 | #ifdef KEY_DEBUGGING | |
318 | key->magic = KEY_DEBUG_MAGIC; | |
319 | #endif | |
320 | ||
29db9190 | 321 | /* let the security module know about the key */ |
7e047ef5 | 322 | ret = security_key_alloc(key, ctx, flags); |
29db9190 DH |
323 | if (ret < 0) |
324 | goto security_error; | |
325 | ||
1da177e4 LT |
326 | /* publish the key by giving it a serial number */ |
327 | atomic_inc(&user->nkeys); | |
328 | key_alloc_serial(key); | |
329 | ||
29db9190 | 330 | error: |
1da177e4 LT |
331 | return key; |
332 | ||
29db9190 DH |
333 | security_error: |
334 | kfree(key->description); | |
1da177e4 | 335 | kmem_cache_free(key_jar, key); |
7e047ef5 | 336 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
1da177e4 LT |
337 | spin_lock(&user->lock); |
338 | user->qnkeys--; | |
339 | user->qnbytes -= quotalen; | |
340 | spin_unlock(&user->lock); | |
341 | } | |
342 | key_user_put(user); | |
29db9190 DH |
343 | key = ERR_PTR(ret); |
344 | goto error; | |
345 | ||
346 | no_memory_3: | |
347 | kmem_cache_free(key_jar, key); | |
348 | no_memory_2: | |
7e047ef5 | 349 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
29db9190 DH |
350 | spin_lock(&user->lock); |
351 | user->qnkeys--; | |
352 | user->qnbytes -= quotalen; | |
353 | spin_unlock(&user->lock); | |
354 | } | |
355 | key_user_put(user); | |
356 | no_memory_1: | |
1da177e4 LT |
357 | key = ERR_PTR(-ENOMEM); |
358 | goto error; | |
359 | ||
29db9190 | 360 | no_quota: |
1da177e4 LT |
361 | spin_unlock(&user->lock); |
362 | key_user_put(user); | |
363 | key = ERR_PTR(-EDQUOT); | |
364 | goto error; | |
365 | ||
366 | } /* end key_alloc() */ | |
367 | ||
368 | EXPORT_SYMBOL(key_alloc); | |
369 | ||
370 | /*****************************************************************************/ | |
371 | /* | |
372 | * reserve an amount of quota for the key's payload | |
373 | */ | |
374 | int key_payload_reserve(struct key *key, size_t datalen) | |
375 | { | |
376 | int delta = (int) datalen - key->datalen; | |
377 | int ret = 0; | |
378 | ||
379 | key_check(key); | |
380 | ||
381 | /* contemplate the quota adjustment */ | |
76d8aeab | 382 | if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { |
1da177e4 LT |
383 | spin_lock(&key->user->lock); |
384 | ||
385 | if (delta > 0 && | |
386 | key->user->qnbytes + delta > KEYQUOTA_MAX_BYTES | |
387 | ) { | |
388 | ret = -EDQUOT; | |
389 | } | |
390 | else { | |
391 | key->user->qnbytes += delta; | |
392 | key->quotalen += delta; | |
393 | } | |
394 | spin_unlock(&key->user->lock); | |
395 | } | |
396 | ||
397 | /* change the recorded data length if that didn't generate an error */ | |
398 | if (ret == 0) | |
399 | key->datalen = datalen; | |
400 | ||
401 | return ret; | |
402 | ||
403 | } /* end key_payload_reserve() */ | |
404 | ||
405 | EXPORT_SYMBOL(key_payload_reserve); | |
406 | ||
407 | /*****************************************************************************/ | |
408 | /* | |
409 | * instantiate a key and link it into the target keyring atomically | |
410 | * - called with the target keyring's semaphore writelocked | |
411 | */ | |
412 | static int __key_instantiate_and_link(struct key *key, | |
413 | const void *data, | |
414 | size_t datalen, | |
3e30148c DH |
415 | struct key *keyring, |
416 | struct key *instkey) | |
1da177e4 LT |
417 | { |
418 | int ret, awaken; | |
419 | ||
420 | key_check(key); | |
421 | key_check(keyring); | |
422 | ||
423 | awaken = 0; | |
424 | ret = -EBUSY; | |
425 | ||
426 | down_write(&key_construction_sem); | |
427 | ||
428 | /* can't instantiate twice */ | |
76d8aeab | 429 | if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { |
1da177e4 LT |
430 | /* instantiate the key */ |
431 | ret = key->type->instantiate(key, data, datalen); | |
432 | ||
433 | if (ret == 0) { | |
434 | /* mark the key as being instantiated */ | |
1da177e4 | 435 | atomic_inc(&key->user->nikeys); |
76d8aeab | 436 | set_bit(KEY_FLAG_INSTANTIATED, &key->flags); |
1da177e4 | 437 | |
76d8aeab | 438 | if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) |
1da177e4 | 439 | awaken = 1; |
1da177e4 LT |
440 | |
441 | /* and link it into the destination keyring */ | |
442 | if (keyring) | |
443 | ret = __key_link(keyring, key); | |
3e30148c DH |
444 | |
445 | /* disable the authorisation key */ | |
446 | if (instkey) | |
447 | key_revoke(instkey); | |
1da177e4 LT |
448 | } |
449 | } | |
450 | ||
451 | up_write(&key_construction_sem); | |
452 | ||
453 | /* wake up anyone waiting for a key to be constructed */ | |
454 | if (awaken) | |
455 | wake_up_all(&request_key_conswq); | |
456 | ||
457 | return ret; | |
458 | ||
459 | } /* end __key_instantiate_and_link() */ | |
460 | ||
461 | /*****************************************************************************/ | |
462 | /* | |
463 | * instantiate a key and link it into the target keyring atomically | |
464 | */ | |
465 | int key_instantiate_and_link(struct key *key, | |
466 | const void *data, | |
467 | size_t datalen, | |
3e30148c DH |
468 | struct key *keyring, |
469 | struct key *instkey) | |
1da177e4 LT |
470 | { |
471 | int ret; | |
472 | ||
473 | if (keyring) | |
474 | down_write(&keyring->sem); | |
475 | ||
3e30148c | 476 | ret = __key_instantiate_and_link(key, data, datalen, keyring, instkey); |
1da177e4 LT |
477 | |
478 | if (keyring) | |
479 | up_write(&keyring->sem); | |
480 | ||
481 | return ret; | |
3e30148c | 482 | |
1da177e4 LT |
483 | } /* end key_instantiate_and_link() */ |
484 | ||
485 | EXPORT_SYMBOL(key_instantiate_and_link); | |
486 | ||
487 | /*****************************************************************************/ | |
488 | /* | |
489 | * negatively instantiate a key and link it into the target keyring atomically | |
490 | */ | |
491 | int key_negate_and_link(struct key *key, | |
492 | unsigned timeout, | |
3e30148c DH |
493 | struct key *keyring, |
494 | struct key *instkey) | |
1da177e4 LT |
495 | { |
496 | struct timespec now; | |
497 | int ret, awaken; | |
498 | ||
499 | key_check(key); | |
500 | key_check(keyring); | |
501 | ||
502 | awaken = 0; | |
503 | ret = -EBUSY; | |
504 | ||
505 | if (keyring) | |
506 | down_write(&keyring->sem); | |
507 | ||
508 | down_write(&key_construction_sem); | |
509 | ||
510 | /* can't instantiate twice */ | |
76d8aeab | 511 | if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { |
1da177e4 | 512 | /* mark the key as being negatively instantiated */ |
1da177e4 | 513 | atomic_inc(&key->user->nikeys); |
76d8aeab DH |
514 | set_bit(KEY_FLAG_NEGATIVE, &key->flags); |
515 | set_bit(KEY_FLAG_INSTANTIATED, &key->flags); | |
1da177e4 LT |
516 | now = current_kernel_time(); |
517 | key->expiry = now.tv_sec + timeout; | |
518 | ||
76d8aeab | 519 | if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) |
1da177e4 | 520 | awaken = 1; |
1da177e4 | 521 | |
1da177e4 LT |
522 | ret = 0; |
523 | ||
524 | /* and link it into the destination keyring */ | |
525 | if (keyring) | |
526 | ret = __key_link(keyring, key); | |
3e30148c DH |
527 | |
528 | /* disable the authorisation key */ | |
529 | if (instkey) | |
530 | key_revoke(instkey); | |
1da177e4 LT |
531 | } |
532 | ||
533 | up_write(&key_construction_sem); | |
534 | ||
535 | if (keyring) | |
536 | up_write(&keyring->sem); | |
537 | ||
538 | /* wake up anyone waiting for a key to be constructed */ | |
539 | if (awaken) | |
540 | wake_up_all(&request_key_conswq); | |
541 | ||
542 | return ret; | |
543 | ||
544 | } /* end key_negate_and_link() */ | |
545 | ||
546 | EXPORT_SYMBOL(key_negate_and_link); | |
547 | ||
548 | /*****************************************************************************/ | |
549 | /* | |
550 | * do cleaning up in process context so that we don't have to disable | |
551 | * interrupts all over the place | |
552 | */ | |
65f27f38 | 553 | static void key_cleanup(struct work_struct *work) |
1da177e4 LT |
554 | { |
555 | struct rb_node *_n; | |
556 | struct key *key; | |
557 | ||
558 | go_again: | |
559 | /* look for a dead key in the tree */ | |
560 | spin_lock(&key_serial_lock); | |
561 | ||
562 | for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { | |
563 | key = rb_entry(_n, struct key, serial_node); | |
564 | ||
565 | if (atomic_read(&key->usage) == 0) | |
566 | goto found_dead_key; | |
567 | } | |
568 | ||
569 | spin_unlock(&key_serial_lock); | |
570 | return; | |
571 | ||
572 | found_dead_key: | |
573 | /* we found a dead key - once we've removed it from the tree, we can | |
574 | * drop the lock */ | |
575 | rb_erase(&key->serial_node, &key_serial_tree); | |
576 | spin_unlock(&key_serial_lock); | |
577 | ||
76d8aeab DH |
578 | key_check(key); |
579 | ||
29db9190 DH |
580 | security_key_free(key); |
581 | ||
1da177e4 | 582 | /* deal with the user's key tracking and quota */ |
76d8aeab | 583 | if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { |
1da177e4 LT |
584 | spin_lock(&key->user->lock); |
585 | key->user->qnkeys--; | |
586 | key->user->qnbytes -= key->quotalen; | |
587 | spin_unlock(&key->user->lock); | |
588 | } | |
589 | ||
590 | atomic_dec(&key->user->nkeys); | |
76d8aeab | 591 | if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) |
1da177e4 LT |
592 | atomic_dec(&key->user->nikeys); |
593 | ||
594 | key_user_put(key->user); | |
595 | ||
596 | /* now throw away the key memory */ | |
597 | if (key->type->destroy) | |
598 | key->type->destroy(key); | |
599 | ||
600 | kfree(key->description); | |
601 | ||
602 | #ifdef KEY_DEBUGGING | |
603 | key->magic = KEY_DEBUG_MAGIC_X; | |
604 | #endif | |
605 | kmem_cache_free(key_jar, key); | |
606 | ||
607 | /* there may, of course, be more than one key to destroy */ | |
608 | goto go_again; | |
609 | ||
610 | } /* end key_cleanup() */ | |
611 | ||
612 | /*****************************************************************************/ | |
613 | /* | |
614 | * dispose of a reference to a key | |
615 | * - when all the references are gone, we schedule the cleanup task to come and | |
616 | * pull it out of the tree in definite process context | |
617 | */ | |
618 | void key_put(struct key *key) | |
619 | { | |
620 | if (key) { | |
621 | key_check(key); | |
622 | ||
623 | if (atomic_dec_and_test(&key->usage)) | |
624 | schedule_work(&key_cleanup_task); | |
625 | } | |
626 | ||
627 | } /* end key_put() */ | |
628 | ||
629 | EXPORT_SYMBOL(key_put); | |
630 | ||
631 | /*****************************************************************************/ | |
632 | /* | |
633 | * find a key by its serial number | |
634 | */ | |
635 | struct key *key_lookup(key_serial_t id) | |
636 | { | |
637 | struct rb_node *n; | |
638 | struct key *key; | |
639 | ||
640 | spin_lock(&key_serial_lock); | |
641 | ||
642 | /* search the tree for the specified key */ | |
643 | n = key_serial_tree.rb_node; | |
644 | while (n) { | |
645 | key = rb_entry(n, struct key, serial_node); | |
646 | ||
647 | if (id < key->serial) | |
648 | n = n->rb_left; | |
649 | else if (id > key->serial) | |
650 | n = n->rb_right; | |
651 | else | |
652 | goto found; | |
653 | } | |
654 | ||
655 | not_found: | |
656 | key = ERR_PTR(-ENOKEY); | |
657 | goto error; | |
658 | ||
659 | found: | |
76d8aeab | 660 | /* pretend it doesn't exist if it's dead */ |
1da177e4 | 661 | if (atomic_read(&key->usage) == 0 || |
76d8aeab | 662 | test_bit(KEY_FLAG_DEAD, &key->flags) || |
1da177e4 LT |
663 | key->type == &key_type_dead) |
664 | goto not_found; | |
665 | ||
666 | /* this races with key_put(), but that doesn't matter since key_put() | |
667 | * doesn't actually change the key | |
668 | */ | |
669 | atomic_inc(&key->usage); | |
670 | ||
671 | error: | |
672 | spin_unlock(&key_serial_lock); | |
673 | return key; | |
674 | ||
675 | } /* end key_lookup() */ | |
676 | ||
677 | /*****************************************************************************/ | |
678 | /* | |
679 | * find and lock the specified key type against removal | |
680 | * - we return with the sem readlocked | |
681 | */ | |
682 | struct key_type *key_type_lookup(const char *type) | |
683 | { | |
684 | struct key_type *ktype; | |
685 | ||
686 | down_read(&key_types_sem); | |
687 | ||
688 | /* look up the key type to see if it's one of the registered kernel | |
689 | * types */ | |
690 | list_for_each_entry(ktype, &key_types_list, link) { | |
691 | if (strcmp(ktype->name, type) == 0) | |
692 | goto found_kernel_type; | |
693 | } | |
694 | ||
695 | up_read(&key_types_sem); | |
696 | ktype = ERR_PTR(-ENOKEY); | |
697 | ||
698 | found_kernel_type: | |
699 | return ktype; | |
700 | ||
701 | } /* end key_type_lookup() */ | |
702 | ||
703 | /*****************************************************************************/ | |
704 | /* | |
705 | * unlock a key type | |
706 | */ | |
707 | void key_type_put(struct key_type *ktype) | |
708 | { | |
709 | up_read(&key_types_sem); | |
710 | ||
711 | } /* end key_type_put() */ | |
712 | ||
713 | /*****************************************************************************/ | |
714 | /* | |
715 | * attempt to update an existing key | |
716 | * - the key has an incremented refcount | |
717 | * - we need to put the key if we get an error | |
718 | */ | |
664cceb0 DH |
719 | static inline key_ref_t __key_update(key_ref_t key_ref, |
720 | const void *payload, size_t plen) | |
1da177e4 | 721 | { |
664cceb0 | 722 | struct key *key = key_ref_to_ptr(key_ref); |
1da177e4 LT |
723 | int ret; |
724 | ||
725 | /* need write permission on the key to update it */ | |
29db9190 DH |
726 | ret = key_permission(key_ref, KEY_WRITE); |
727 | if (ret < 0) | |
1da177e4 LT |
728 | goto error; |
729 | ||
730 | ret = -EEXIST; | |
731 | if (!key->type->update) | |
732 | goto error; | |
733 | ||
734 | down_write(&key->sem); | |
735 | ||
736 | ret = key->type->update(key, payload, plen); | |
76d8aeab | 737 | if (ret == 0) |
1da177e4 | 738 | /* updating a negative key instantiates it */ |
76d8aeab | 739 | clear_bit(KEY_FLAG_NEGATIVE, &key->flags); |
1da177e4 LT |
740 | |
741 | up_write(&key->sem); | |
742 | ||
743 | if (ret < 0) | |
744 | goto error; | |
664cceb0 DH |
745 | out: |
746 | return key_ref; | |
1da177e4 | 747 | |
664cceb0 | 748 | error: |
1da177e4 | 749 | key_put(key); |
664cceb0 | 750 | key_ref = ERR_PTR(ret); |
1da177e4 LT |
751 | goto out; |
752 | ||
753 | } /* end __key_update() */ | |
754 | ||
755 | /*****************************************************************************/ | |
756 | /* | |
757 | * search the specified keyring for a key of the same description; if one is | |
758 | * found, update it, otherwise add a new one | |
759 | */ | |
664cceb0 DH |
760 | key_ref_t key_create_or_update(key_ref_t keyring_ref, |
761 | const char *type, | |
762 | const char *description, | |
763 | const void *payload, | |
764 | size_t plen, | |
7e047ef5 | 765 | unsigned long flags) |
1da177e4 LT |
766 | { |
767 | struct key_type *ktype; | |
664cceb0 | 768 | struct key *keyring, *key = NULL; |
1da177e4 | 769 | key_perm_t perm; |
664cceb0 | 770 | key_ref_t key_ref; |
1da177e4 LT |
771 | int ret; |
772 | ||
1da177e4 LT |
773 | /* look up the key type to see if it's one of the registered kernel |
774 | * types */ | |
775 | ktype = key_type_lookup(type); | |
776 | if (IS_ERR(ktype)) { | |
664cceb0 | 777 | key_ref = ERR_PTR(-ENODEV); |
1da177e4 LT |
778 | goto error; |
779 | } | |
780 | ||
664cceb0 | 781 | key_ref = ERR_PTR(-EINVAL); |
1da177e4 LT |
782 | if (!ktype->match || !ktype->instantiate) |
783 | goto error_2; | |
784 | ||
664cceb0 DH |
785 | keyring = key_ref_to_ptr(keyring_ref); |
786 | ||
787 | key_check(keyring); | |
788 | ||
c3a9d654 DH |
789 | key_ref = ERR_PTR(-ENOTDIR); |
790 | if (keyring->type != &key_type_keyring) | |
791 | goto error_2; | |
792 | ||
664cceb0 DH |
793 | down_write(&keyring->sem); |
794 | ||
795 | /* if we're going to allocate a new key, we're going to have | |
796 | * to modify the keyring */ | |
29db9190 DH |
797 | ret = key_permission(keyring_ref, KEY_WRITE); |
798 | if (ret < 0) { | |
799 | key_ref = ERR_PTR(ret); | |
664cceb0 | 800 | goto error_3; |
29db9190 | 801 | } |
664cceb0 | 802 | |
1d9b7d97 DH |
803 | /* if it's possible to update this type of key, search for an existing |
804 | * key of the same type and description in the destination keyring and | |
805 | * update that instead if possible | |
1da177e4 | 806 | */ |
1d9b7d97 DH |
807 | if (ktype->update) { |
808 | key_ref = __keyring_search_one(keyring_ref, ktype, description, | |
809 | 0); | |
810 | if (!IS_ERR(key_ref)) | |
811 | goto found_matching_key; | |
812 | } | |
1da177e4 | 813 | |
1da177e4 | 814 | /* decide on the permissions we want */ |
29db9190 DH |
815 | perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR; |
816 | perm |= KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK | KEY_USR_SETATTR; | |
1da177e4 LT |
817 | |
818 | if (ktype->read) | |
664cceb0 | 819 | perm |= KEY_POS_READ | KEY_USR_READ; |
1da177e4 LT |
820 | |
821 | if (ktype == &key_type_keyring || ktype->update) | |
822 | perm |= KEY_USR_WRITE; | |
823 | ||
824 | /* allocate a new key */ | |
825 | key = key_alloc(ktype, description, current->fsuid, current->fsgid, | |
7e047ef5 | 826 | current, perm, flags); |
1da177e4 | 827 | if (IS_ERR(key)) { |
664cceb0 | 828 | key_ref = ERR_PTR(PTR_ERR(key)); |
1da177e4 LT |
829 | goto error_3; |
830 | } | |
831 | ||
832 | /* instantiate it and link it into the target keyring */ | |
3e30148c | 833 | ret = __key_instantiate_and_link(key, payload, plen, keyring, NULL); |
1da177e4 LT |
834 | if (ret < 0) { |
835 | key_put(key); | |
664cceb0 DH |
836 | key_ref = ERR_PTR(ret); |
837 | goto error_3; | |
1da177e4 LT |
838 | } |
839 | ||
664cceb0 DH |
840 | key_ref = make_key_ref(key, is_key_possessed(keyring_ref)); |
841 | ||
1da177e4 LT |
842 | error_3: |
843 | up_write(&keyring->sem); | |
844 | error_2: | |
845 | key_type_put(ktype); | |
846 | error: | |
664cceb0 | 847 | return key_ref; |
1da177e4 LT |
848 | |
849 | found_matching_key: | |
850 | /* we found a matching key, so we're going to try to update it | |
851 | * - we can drop the locks first as we have the key pinned | |
852 | */ | |
853 | up_write(&keyring->sem); | |
854 | key_type_put(ktype); | |
855 | ||
664cceb0 | 856 | key_ref = __key_update(key_ref, payload, plen); |
1da177e4 LT |
857 | goto error; |
858 | ||
859 | } /* end key_create_or_update() */ | |
860 | ||
861 | EXPORT_SYMBOL(key_create_or_update); | |
862 | ||
863 | /*****************************************************************************/ | |
864 | /* | |
865 | * update a key | |
866 | */ | |
664cceb0 | 867 | int key_update(key_ref_t key_ref, const void *payload, size_t plen) |
1da177e4 | 868 | { |
664cceb0 | 869 | struct key *key = key_ref_to_ptr(key_ref); |
1da177e4 LT |
870 | int ret; |
871 | ||
872 | key_check(key); | |
873 | ||
874 | /* the key must be writable */ | |
29db9190 DH |
875 | ret = key_permission(key_ref, KEY_WRITE); |
876 | if (ret < 0) | |
1da177e4 LT |
877 | goto error; |
878 | ||
879 | /* attempt to update it if supported */ | |
880 | ret = -EOPNOTSUPP; | |
881 | if (key->type->update) { | |
882 | down_write(&key->sem); | |
1da177e4 | 883 | |
29db9190 | 884 | ret = key->type->update(key, payload, plen); |
76d8aeab | 885 | if (ret == 0) |
1da177e4 | 886 | /* updating a negative key instantiates it */ |
76d8aeab | 887 | clear_bit(KEY_FLAG_NEGATIVE, &key->flags); |
1da177e4 LT |
888 | |
889 | up_write(&key->sem); | |
890 | } | |
891 | ||
892 | error: | |
893 | return ret; | |
894 | ||
895 | } /* end key_update() */ | |
896 | ||
897 | EXPORT_SYMBOL(key_update); | |
898 | ||
1da177e4 LT |
899 | /*****************************************************************************/ |
900 | /* | |
901 | * revoke a key | |
902 | */ | |
903 | void key_revoke(struct key *key) | |
904 | { | |
905 | key_check(key); | |
906 | ||
907 | /* make sure no one's trying to change or use the key when we mark | |
908 | * it */ | |
909 | down_write(&key->sem); | |
76d8aeab | 910 | set_bit(KEY_FLAG_REVOKED, &key->flags); |
04c567d9 DH |
911 | |
912 | if (key->type->revoke) | |
913 | key->type->revoke(key); | |
914 | ||
1da177e4 LT |
915 | up_write(&key->sem); |
916 | ||
917 | } /* end key_revoke() */ | |
918 | ||
919 | EXPORT_SYMBOL(key_revoke); | |
920 | ||
921 | /*****************************************************************************/ | |
922 | /* | |
923 | * register a type of key | |
924 | */ | |
925 | int register_key_type(struct key_type *ktype) | |
926 | { | |
927 | struct key_type *p; | |
928 | int ret; | |
929 | ||
930 | ret = -EEXIST; | |
931 | down_write(&key_types_sem); | |
932 | ||
933 | /* disallow key types with the same name */ | |
934 | list_for_each_entry(p, &key_types_list, link) { | |
935 | if (strcmp(p->name, ktype->name) == 0) | |
936 | goto out; | |
937 | } | |
938 | ||
939 | /* store the type */ | |
940 | list_add(&ktype->link, &key_types_list); | |
941 | ret = 0; | |
942 | ||
943 | out: | |
944 | up_write(&key_types_sem); | |
945 | return ret; | |
946 | ||
947 | } /* end register_key_type() */ | |
948 | ||
949 | EXPORT_SYMBOL(register_key_type); | |
950 | ||
951 | /*****************************************************************************/ | |
952 | /* | |
953 | * unregister a type of key | |
954 | */ | |
955 | void unregister_key_type(struct key_type *ktype) | |
956 | { | |
957 | struct rb_node *_n; | |
958 | struct key *key; | |
959 | ||
960 | down_write(&key_types_sem); | |
961 | ||
962 | /* withdraw the key type */ | |
963 | list_del_init(&ktype->link); | |
964 | ||
76d8aeab | 965 | /* mark all the keys of this type dead */ |
1da177e4 LT |
966 | spin_lock(&key_serial_lock); |
967 | ||
968 | for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { | |
969 | key = rb_entry(_n, struct key, serial_node); | |
970 | ||
76d8aeab DH |
971 | if (key->type == ktype) |
972 | key->type = &key_type_dead; | |
973 | } | |
974 | ||
975 | spin_unlock(&key_serial_lock); | |
976 | ||
977 | /* make sure everyone revalidates their keys */ | |
b2b18660 | 978 | synchronize_rcu(); |
76d8aeab DH |
979 | |
980 | /* we should now be able to destroy the payloads of all the keys of | |
981 | * this type with impunity */ | |
982 | spin_lock(&key_serial_lock); | |
1da177e4 | 983 | |
76d8aeab DH |
984 | for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { |
985 | key = rb_entry(_n, struct key, serial_node); | |
1da177e4 | 986 | |
76d8aeab DH |
987 | if (key->type == ktype) { |
988 | if (ktype->destroy) | |
989 | ktype->destroy(key); | |
a7807a32 | 990 | memset(&key->payload, KEY_DESTROY, sizeof(key->payload)); |
76d8aeab | 991 | } |
1da177e4 LT |
992 | } |
993 | ||
994 | spin_unlock(&key_serial_lock); | |
995 | up_write(&key_types_sem); | |
996 | ||
997 | } /* end unregister_key_type() */ | |
998 | ||
999 | EXPORT_SYMBOL(unregister_key_type); | |
1000 | ||
1001 | /*****************************************************************************/ | |
1002 | /* | |
1003 | * initialise the key management stuff | |
1004 | */ | |
1005 | void __init key_init(void) | |
1006 | { | |
1007 | /* allocate a slab in which we can store keys */ | |
1008 | key_jar = kmem_cache_create("key_jar", sizeof(struct key), | |
1009 | 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1010 | ||
1011 | /* add the special key types */ | |
1012 | list_add_tail(&key_type_keyring.link, &key_types_list); | |
1013 | list_add_tail(&key_type_dead.link, &key_types_list); | |
1014 | list_add_tail(&key_type_user.link, &key_types_list); | |
1015 | ||
1016 | /* record the root user tracking */ | |
1017 | rb_link_node(&root_key_user.node, | |
1018 | NULL, | |
1019 | &key_user_tree.rb_node); | |
1020 | ||
1021 | rb_insert_color(&root_key_user.node, | |
1022 | &key_user_tree); | |
1023 | ||
1024 | /* record root's user standard keyrings */ | |
1025 | key_check(&root_user_keyring); | |
1026 | key_check(&root_session_keyring); | |
1027 | ||
1028 | __key_insert_serial(&root_user_keyring); | |
1029 | __key_insert_serial(&root_session_keyring); | |
1030 | ||
1031 | keyring_publish_name(&root_user_keyring); | |
1032 | keyring_publish_name(&root_session_keyring); | |
1033 | ||
1034 | /* link the two root keyrings together */ | |
1035 | key_link(&root_session_keyring, &root_user_keyring); | |
76d8aeab | 1036 | |
1da177e4 | 1037 | } /* end key_init() */ |