Commit | Line | Data |
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76181c13 | 1 | /* Basic authentication token and access key management |
1da177e4 | 2 | * |
69664cf1 | 3 | * Copyright (C) 2004-2008 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 | ||
0b77f5bf DH |
30 | unsigned int key_quota_root_maxkeys = 200; /* root's key count quota */ |
31 | unsigned int key_quota_root_maxbytes = 20000; /* root's key space quota */ | |
32 | unsigned int key_quota_maxkeys = 200; /* general key count quota */ | |
33 | unsigned int key_quota_maxbytes = 20000; /* general key space quota */ | |
34 | ||
1da177e4 LT |
35 | static LIST_HEAD(key_types_list); |
36 | static DECLARE_RWSEM(key_types_sem); | |
37 | ||
65f27f38 DH |
38 | static void key_cleanup(struct work_struct *work); |
39 | static DECLARE_WORK(key_cleanup_task, key_cleanup); | |
1da177e4 LT |
40 | |
41 | /* we serialise key instantiation and link */ | |
76181c13 | 42 | DEFINE_MUTEX(key_construction_mutex); |
1da177e4 LT |
43 | |
44 | /* any key who's type gets unegistered will be re-typed to this */ | |
1ae8f407 | 45 | static struct key_type key_type_dead = { |
1da177e4 LT |
46 | .name = "dead", |
47 | }; | |
48 | ||
49 | #ifdef KEY_DEBUGGING | |
50 | void __key_check(const struct key *key) | |
51 | { | |
52 | printk("__key_check: key %p {%08x} should be {%08x}\n", | |
53 | key, key->magic, KEY_DEBUG_MAGIC); | |
54 | BUG(); | |
55 | } | |
56 | #endif | |
57 | ||
58 | /*****************************************************************************/ | |
59 | /* | |
60 | * get the key quota record for a user, allocating a new record if one doesn't | |
61 | * already exist | |
62 | */ | |
63 | struct key_user *key_user_lookup(uid_t uid) | |
64 | { | |
65 | struct key_user *candidate = NULL, *user; | |
66 | struct rb_node *parent = NULL; | |
67 | struct rb_node **p; | |
68 | ||
69 | try_again: | |
70 | p = &key_user_tree.rb_node; | |
71 | spin_lock(&key_user_lock); | |
72 | ||
73 | /* search the tree for a user record with a matching UID */ | |
74 | while (*p) { | |
75 | parent = *p; | |
76 | user = rb_entry(parent, struct key_user, node); | |
77 | ||
78 | if (uid < user->uid) | |
79 | p = &(*p)->rb_left; | |
80 | else if (uid > user->uid) | |
81 | p = &(*p)->rb_right; | |
82 | else | |
83 | goto found; | |
84 | } | |
85 | ||
86 | /* if we get here, we failed to find a match in the tree */ | |
87 | if (!candidate) { | |
88 | /* allocate a candidate user record if we don't already have | |
89 | * one */ | |
90 | spin_unlock(&key_user_lock); | |
91 | ||
92 | user = NULL; | |
93 | candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL); | |
94 | if (unlikely(!candidate)) | |
95 | goto out; | |
96 | ||
97 | /* the allocation may have scheduled, so we need to repeat the | |
98 | * search lest someone else added the record whilst we were | |
99 | * asleep */ | |
100 | goto try_again; | |
101 | } | |
102 | ||
103 | /* if we get here, then the user record still hadn't appeared on the | |
104 | * second pass - so we use the candidate record */ | |
105 | atomic_set(&candidate->usage, 1); | |
106 | atomic_set(&candidate->nkeys, 0); | |
107 | atomic_set(&candidate->nikeys, 0); | |
108 | candidate->uid = uid; | |
109 | candidate->qnkeys = 0; | |
110 | candidate->qnbytes = 0; | |
111 | spin_lock_init(&candidate->lock); | |
76181c13 | 112 | mutex_init(&candidate->cons_lock); |
1da177e4 LT |
113 | |
114 | rb_link_node(&candidate->node, parent, p); | |
115 | rb_insert_color(&candidate->node, &key_user_tree); | |
116 | spin_unlock(&key_user_lock); | |
117 | user = candidate; | |
118 | goto out; | |
119 | ||
120 | /* okay - we found a user record for this UID */ | |
121 | found: | |
122 | atomic_inc(&user->usage); | |
123 | spin_unlock(&key_user_lock); | |
a7f988ba | 124 | kfree(candidate); |
1da177e4 LT |
125 | out: |
126 | return user; | |
127 | ||
128 | } /* end key_user_lookup() */ | |
129 | ||
130 | /*****************************************************************************/ | |
131 | /* | |
132 | * dispose of a user structure | |
133 | */ | |
134 | void key_user_put(struct key_user *user) | |
135 | { | |
136 | if (atomic_dec_and_lock(&user->usage, &key_user_lock)) { | |
137 | rb_erase(&user->node, &key_user_tree); | |
138 | spin_unlock(&key_user_lock); | |
139 | ||
140 | kfree(user); | |
141 | } | |
142 | ||
143 | } /* end key_user_put() */ | |
144 | ||
1da177e4 LT |
145 | /*****************************************************************************/ |
146 | /* | |
147 | * assign a key the next unique serial number | |
e51f6d34 ML |
148 | * - these are assigned randomly to avoid security issues through covert |
149 | * channel problems | |
1da177e4 LT |
150 | */ |
151 | static inline void key_alloc_serial(struct key *key) | |
152 | { | |
153 | struct rb_node *parent, **p; | |
154 | struct key *xkey; | |
155 | ||
e51f6d34 | 156 | /* propose a random serial number and look for a hole for it in the |
1da177e4 | 157 | * serial number tree */ |
e51f6d34 ML |
158 | do { |
159 | get_random_bytes(&key->serial, sizeof(key->serial)); | |
160 | ||
161 | key->serial >>= 1; /* negative numbers are not permitted */ | |
162 | } while (key->serial < 3); | |
163 | ||
164 | spin_lock(&key_serial_lock); | |
1da177e4 | 165 | |
9ad0830f | 166 | attempt_insertion: |
1da177e4 LT |
167 | parent = NULL; |
168 | p = &key_serial_tree.rb_node; | |
169 | ||
170 | while (*p) { | |
171 | parent = *p; | |
172 | xkey = rb_entry(parent, struct key, serial_node); | |
173 | ||
174 | if (key->serial < xkey->serial) | |
175 | p = &(*p)->rb_left; | |
176 | else if (key->serial > xkey->serial) | |
177 | p = &(*p)->rb_right; | |
178 | else | |
179 | goto serial_exists; | |
180 | } | |
9ad0830f DH |
181 | |
182 | /* we've found a suitable hole - arrange for this key to occupy it */ | |
183 | rb_link_node(&key->serial_node, parent, p); | |
184 | rb_insert_color(&key->serial_node, &key_serial_tree); | |
185 | ||
186 | spin_unlock(&key_serial_lock); | |
187 | return; | |
1da177e4 LT |
188 | |
189 | /* we found a key with the proposed serial number - walk the tree from | |
190 | * that point looking for the next unused serial number */ | |
e51f6d34 | 191 | serial_exists: |
1da177e4 | 192 | for (;;) { |
e51f6d34 | 193 | key->serial++; |
9ad0830f DH |
194 | if (key->serial < 3) { |
195 | key->serial = 3; | |
196 | goto attempt_insertion; | |
197 | } | |
1da177e4 LT |
198 | |
199 | parent = rb_next(parent); | |
200 | if (!parent) | |
9ad0830f | 201 | goto attempt_insertion; |
1da177e4 LT |
202 | |
203 | xkey = rb_entry(parent, struct key, serial_node); | |
204 | if (key->serial < xkey->serial) | |
9ad0830f | 205 | goto attempt_insertion; |
1da177e4 LT |
206 | } |
207 | ||
1da177e4 LT |
208 | } /* end key_alloc_serial() */ |
209 | ||
210 | /*****************************************************************************/ | |
211 | /* | |
212 | * allocate a key of the specified type | |
213 | * - update the user's quota to reflect the existence of the key | |
8d9067bd DH |
214 | * - called from a key-type operation with key_types_sem read-locked by |
215 | * key_create_or_update() | |
216 | * - this prevents unregistration of the key type | |
1da177e4 LT |
217 | * - upon return the key is as yet uninstantiated; the caller needs to either |
218 | * instantiate the key or discard it before returning | |
219 | */ | |
220 | struct key *key_alloc(struct key_type *type, const char *desc, | |
d84f4f99 | 221 | uid_t uid, gid_t gid, const struct cred *cred, |
7e047ef5 | 222 | key_perm_t perm, unsigned long flags) |
1da177e4 LT |
223 | { |
224 | struct key_user *user = NULL; | |
225 | struct key *key; | |
226 | size_t desclen, quotalen; | |
29db9190 | 227 | int ret; |
1da177e4 LT |
228 | |
229 | key = ERR_PTR(-EINVAL); | |
230 | if (!desc || !*desc) | |
231 | goto error; | |
232 | ||
233 | desclen = strlen(desc) + 1; | |
234 | quotalen = desclen + type->def_datalen; | |
235 | ||
236 | /* get hold of the key tracking for this user */ | |
237 | user = key_user_lookup(uid); | |
238 | if (!user) | |
239 | goto no_memory_1; | |
240 | ||
241 | /* check that the user's quota permits allocation of another key and | |
242 | * its description */ | |
7e047ef5 | 243 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
0b77f5bf DH |
244 | unsigned maxkeys = (uid == 0) ? |
245 | key_quota_root_maxkeys : key_quota_maxkeys; | |
246 | unsigned maxbytes = (uid == 0) ? | |
247 | key_quota_root_maxbytes : key_quota_maxbytes; | |
248 | ||
1da177e4 | 249 | spin_lock(&user->lock); |
7e047ef5 | 250 | if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) { |
0b77f5bf DH |
251 | if (user->qnkeys + 1 >= maxkeys || |
252 | user->qnbytes + quotalen >= maxbytes || | |
253 | user->qnbytes + quotalen < user->qnbytes) | |
7e047ef5 DH |
254 | goto no_quota; |
255 | } | |
1da177e4 LT |
256 | |
257 | user->qnkeys++; | |
258 | user->qnbytes += quotalen; | |
259 | spin_unlock(&user->lock); | |
260 | } | |
261 | ||
262 | /* allocate and initialise the key and its description */ | |
e94b1766 | 263 | key = kmem_cache_alloc(key_jar, GFP_KERNEL); |
1da177e4 LT |
264 | if (!key) |
265 | goto no_memory_2; | |
266 | ||
267 | if (desc) { | |
48ad504e | 268 | key->description = kmemdup(desc, desclen, GFP_KERNEL); |
1da177e4 LT |
269 | if (!key->description) |
270 | goto no_memory_3; | |
1da177e4 LT |
271 | } |
272 | ||
273 | atomic_set(&key->usage, 1); | |
1da177e4 LT |
274 | init_rwsem(&key->sem); |
275 | key->type = type; | |
276 | key->user = user; | |
277 | key->quotalen = quotalen; | |
278 | key->datalen = type->def_datalen; | |
279 | key->uid = uid; | |
280 | key->gid = gid; | |
281 | key->perm = perm; | |
282 | key->flags = 0; | |
283 | key->expiry = 0; | |
284 | key->payload.data = NULL; | |
29db9190 | 285 | key->security = NULL; |
1da177e4 | 286 | |
7e047ef5 | 287 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) |
76d8aeab | 288 | key->flags |= 1 << KEY_FLAG_IN_QUOTA; |
1da177e4 LT |
289 | |
290 | memset(&key->type_data, 0, sizeof(key->type_data)); | |
291 | ||
292 | #ifdef KEY_DEBUGGING | |
293 | key->magic = KEY_DEBUG_MAGIC; | |
294 | #endif | |
295 | ||
29db9190 | 296 | /* let the security module know about the key */ |
d84f4f99 | 297 | ret = security_key_alloc(key, cred, flags); |
29db9190 DH |
298 | if (ret < 0) |
299 | goto security_error; | |
300 | ||
1da177e4 LT |
301 | /* publish the key by giving it a serial number */ |
302 | atomic_inc(&user->nkeys); | |
303 | key_alloc_serial(key); | |
304 | ||
29db9190 | 305 | error: |
1da177e4 LT |
306 | return key; |
307 | ||
29db9190 DH |
308 | security_error: |
309 | kfree(key->description); | |
1da177e4 | 310 | kmem_cache_free(key_jar, key); |
7e047ef5 | 311 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
1da177e4 LT |
312 | spin_lock(&user->lock); |
313 | user->qnkeys--; | |
314 | user->qnbytes -= quotalen; | |
315 | spin_unlock(&user->lock); | |
316 | } | |
317 | key_user_put(user); | |
29db9190 DH |
318 | key = ERR_PTR(ret); |
319 | goto error; | |
320 | ||
321 | no_memory_3: | |
322 | kmem_cache_free(key_jar, key); | |
323 | no_memory_2: | |
7e047ef5 | 324 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
29db9190 DH |
325 | spin_lock(&user->lock); |
326 | user->qnkeys--; | |
327 | user->qnbytes -= quotalen; | |
328 | spin_unlock(&user->lock); | |
329 | } | |
330 | key_user_put(user); | |
331 | no_memory_1: | |
1da177e4 LT |
332 | key = ERR_PTR(-ENOMEM); |
333 | goto error; | |
334 | ||
29db9190 | 335 | no_quota: |
1da177e4 LT |
336 | spin_unlock(&user->lock); |
337 | key_user_put(user); | |
338 | key = ERR_PTR(-EDQUOT); | |
339 | goto error; | |
340 | ||
341 | } /* end key_alloc() */ | |
342 | ||
343 | EXPORT_SYMBOL(key_alloc); | |
344 | ||
345 | /*****************************************************************************/ | |
346 | /* | |
347 | * reserve an amount of quota for the key's payload | |
348 | */ | |
349 | int key_payload_reserve(struct key *key, size_t datalen) | |
350 | { | |
351 | int delta = (int) datalen - key->datalen; | |
352 | int ret = 0; | |
353 | ||
354 | key_check(key); | |
355 | ||
356 | /* contemplate the quota adjustment */ | |
76d8aeab | 357 | if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { |
0b77f5bf DH |
358 | unsigned maxbytes = (key->user->uid == 0) ? |
359 | key_quota_root_maxbytes : key_quota_maxbytes; | |
360 | ||
1da177e4 LT |
361 | spin_lock(&key->user->lock); |
362 | ||
363 | if (delta > 0 && | |
0b77f5bf DH |
364 | (key->user->qnbytes + delta >= maxbytes || |
365 | key->user->qnbytes + delta < key->user->qnbytes)) { | |
1da177e4 LT |
366 | ret = -EDQUOT; |
367 | } | |
368 | else { | |
369 | key->user->qnbytes += delta; | |
370 | key->quotalen += delta; | |
371 | } | |
372 | spin_unlock(&key->user->lock); | |
373 | } | |
374 | ||
375 | /* change the recorded data length if that didn't generate an error */ | |
376 | if (ret == 0) | |
377 | key->datalen = datalen; | |
378 | ||
379 | return ret; | |
380 | ||
381 | } /* end key_payload_reserve() */ | |
382 | ||
383 | EXPORT_SYMBOL(key_payload_reserve); | |
384 | ||
385 | /*****************************************************************************/ | |
386 | /* | |
387 | * instantiate a key and link it into the target keyring atomically | |
388 | * - called with the target keyring's semaphore writelocked | |
389 | */ | |
390 | static int __key_instantiate_and_link(struct key *key, | |
391 | const void *data, | |
392 | size_t datalen, | |
3e30148c | 393 | struct key *keyring, |
d84f4f99 | 394 | struct key *authkey) |
1da177e4 LT |
395 | { |
396 | int ret, awaken; | |
397 | ||
398 | key_check(key); | |
399 | key_check(keyring); | |
400 | ||
401 | awaken = 0; | |
402 | ret = -EBUSY; | |
403 | ||
76181c13 | 404 | mutex_lock(&key_construction_mutex); |
1da177e4 LT |
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); | |
3e30148c DH |
422 | |
423 | /* disable the authorisation key */ | |
d84f4f99 DH |
424 | if (authkey) |
425 | key_revoke(authkey); | |
1da177e4 LT |
426 | } |
427 | } | |
428 | ||
76181c13 | 429 | mutex_unlock(&key_construction_mutex); |
1da177e4 LT |
430 | |
431 | /* wake up anyone waiting for a key to be constructed */ | |
432 | if (awaken) | |
76181c13 | 433 | wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT); |
1da177e4 LT |
434 | |
435 | return ret; | |
436 | ||
437 | } /* end __key_instantiate_and_link() */ | |
438 | ||
439 | /*****************************************************************************/ | |
440 | /* | |
441 | * instantiate a key and link it into the target keyring atomically | |
442 | */ | |
443 | int key_instantiate_and_link(struct key *key, | |
444 | const void *data, | |
445 | size_t datalen, | |
3e30148c | 446 | struct key *keyring, |
d84f4f99 | 447 | struct key *authkey) |
1da177e4 LT |
448 | { |
449 | int ret; | |
450 | ||
451 | if (keyring) | |
452 | down_write(&keyring->sem); | |
453 | ||
d84f4f99 | 454 | ret = __key_instantiate_and_link(key, data, datalen, keyring, authkey); |
1da177e4 LT |
455 | |
456 | if (keyring) | |
457 | up_write(&keyring->sem); | |
458 | ||
459 | return ret; | |
3e30148c | 460 | |
1da177e4 LT |
461 | } /* end key_instantiate_and_link() */ |
462 | ||
463 | EXPORT_SYMBOL(key_instantiate_and_link); | |
464 | ||
465 | /*****************************************************************************/ | |
466 | /* | |
467 | * negatively instantiate a key and link it into the target keyring atomically | |
468 | */ | |
469 | int key_negate_and_link(struct key *key, | |
470 | unsigned timeout, | |
3e30148c | 471 | struct key *keyring, |
d84f4f99 | 472 | struct key *authkey) |
1da177e4 LT |
473 | { |
474 | struct timespec now; | |
475 | int ret, awaken; | |
476 | ||
477 | key_check(key); | |
478 | key_check(keyring); | |
479 | ||
480 | awaken = 0; | |
481 | ret = -EBUSY; | |
482 | ||
483 | if (keyring) | |
484 | down_write(&keyring->sem); | |
485 | ||
76181c13 | 486 | mutex_lock(&key_construction_mutex); |
1da177e4 LT |
487 | |
488 | /* can't instantiate twice */ | |
76d8aeab | 489 | if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { |
1da177e4 | 490 | /* mark the key as being negatively instantiated */ |
1da177e4 | 491 | atomic_inc(&key->user->nikeys); |
76d8aeab DH |
492 | set_bit(KEY_FLAG_NEGATIVE, &key->flags); |
493 | set_bit(KEY_FLAG_INSTANTIATED, &key->flags); | |
1da177e4 LT |
494 | now = current_kernel_time(); |
495 | key->expiry = now.tv_sec + timeout; | |
496 | ||
76d8aeab | 497 | if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) |
1da177e4 | 498 | awaken = 1; |
1da177e4 | 499 | |
1da177e4 LT |
500 | ret = 0; |
501 | ||
502 | /* and link it into the destination keyring */ | |
503 | if (keyring) | |
504 | ret = __key_link(keyring, key); | |
3e30148c DH |
505 | |
506 | /* disable the authorisation key */ | |
d84f4f99 DH |
507 | if (authkey) |
508 | key_revoke(authkey); | |
1da177e4 LT |
509 | } |
510 | ||
76181c13 | 511 | mutex_unlock(&key_construction_mutex); |
1da177e4 LT |
512 | |
513 | if (keyring) | |
514 | up_write(&keyring->sem); | |
515 | ||
516 | /* wake up anyone waiting for a key to be constructed */ | |
517 | if (awaken) | |
76181c13 | 518 | wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT); |
1da177e4 LT |
519 | |
520 | return ret; | |
521 | ||
522 | } /* end key_negate_and_link() */ | |
523 | ||
524 | EXPORT_SYMBOL(key_negate_and_link); | |
525 | ||
526 | /*****************************************************************************/ | |
527 | /* | |
528 | * do cleaning up in process context so that we don't have to disable | |
529 | * interrupts all over the place | |
530 | */ | |
65f27f38 | 531 | static void key_cleanup(struct work_struct *work) |
1da177e4 LT |
532 | { |
533 | struct rb_node *_n; | |
534 | struct key *key; | |
535 | ||
536 | go_again: | |
537 | /* look for a dead key in the tree */ | |
538 | spin_lock(&key_serial_lock); | |
539 | ||
540 | for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { | |
541 | key = rb_entry(_n, struct key, serial_node); | |
542 | ||
543 | if (atomic_read(&key->usage) == 0) | |
544 | goto found_dead_key; | |
545 | } | |
546 | ||
547 | spin_unlock(&key_serial_lock); | |
548 | return; | |
549 | ||
550 | found_dead_key: | |
551 | /* we found a dead key - once we've removed it from the tree, we can | |
552 | * drop the lock */ | |
553 | rb_erase(&key->serial_node, &key_serial_tree); | |
554 | spin_unlock(&key_serial_lock); | |
555 | ||
76d8aeab DH |
556 | key_check(key); |
557 | ||
29db9190 DH |
558 | security_key_free(key); |
559 | ||
1da177e4 | 560 | /* deal with the user's key tracking and quota */ |
76d8aeab | 561 | if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { |
1da177e4 LT |
562 | spin_lock(&key->user->lock); |
563 | key->user->qnkeys--; | |
564 | key->user->qnbytes -= key->quotalen; | |
565 | spin_unlock(&key->user->lock); | |
566 | } | |
567 | ||
568 | atomic_dec(&key->user->nkeys); | |
76d8aeab | 569 | if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) |
1da177e4 LT |
570 | atomic_dec(&key->user->nikeys); |
571 | ||
572 | key_user_put(key->user); | |
573 | ||
574 | /* now throw away the key memory */ | |
575 | if (key->type->destroy) | |
576 | key->type->destroy(key); | |
577 | ||
578 | kfree(key->description); | |
579 | ||
580 | #ifdef KEY_DEBUGGING | |
581 | key->magic = KEY_DEBUG_MAGIC_X; | |
582 | #endif | |
583 | kmem_cache_free(key_jar, key); | |
584 | ||
585 | /* there may, of course, be more than one key to destroy */ | |
586 | goto go_again; | |
587 | ||
588 | } /* end key_cleanup() */ | |
589 | ||
590 | /*****************************************************************************/ | |
591 | /* | |
592 | * dispose of a reference to a key | |
593 | * - when all the references are gone, we schedule the cleanup task to come and | |
594 | * pull it out of the tree in definite process context | |
595 | */ | |
596 | void key_put(struct key *key) | |
597 | { | |
598 | if (key) { | |
599 | key_check(key); | |
600 | ||
601 | if (atomic_dec_and_test(&key->usage)) | |
602 | schedule_work(&key_cleanup_task); | |
603 | } | |
604 | ||
605 | } /* end key_put() */ | |
606 | ||
607 | EXPORT_SYMBOL(key_put); | |
608 | ||
609 | /*****************************************************************************/ | |
610 | /* | |
611 | * find a key by its serial number | |
612 | */ | |
613 | struct key *key_lookup(key_serial_t id) | |
614 | { | |
615 | struct rb_node *n; | |
616 | struct key *key; | |
617 | ||
618 | spin_lock(&key_serial_lock); | |
619 | ||
620 | /* search the tree for the specified key */ | |
621 | n = key_serial_tree.rb_node; | |
622 | while (n) { | |
623 | key = rb_entry(n, struct key, serial_node); | |
624 | ||
625 | if (id < key->serial) | |
626 | n = n->rb_left; | |
627 | else if (id > key->serial) | |
628 | n = n->rb_right; | |
629 | else | |
630 | goto found; | |
631 | } | |
632 | ||
633 | not_found: | |
634 | key = ERR_PTR(-ENOKEY); | |
635 | goto error; | |
636 | ||
637 | found: | |
76d8aeab | 638 | /* pretend it doesn't exist if it's dead */ |
1da177e4 | 639 | if (atomic_read(&key->usage) == 0 || |
76d8aeab | 640 | test_bit(KEY_FLAG_DEAD, &key->flags) || |
1da177e4 LT |
641 | key->type == &key_type_dead) |
642 | goto not_found; | |
643 | ||
644 | /* this races with key_put(), but that doesn't matter since key_put() | |
645 | * doesn't actually change the key | |
646 | */ | |
647 | atomic_inc(&key->usage); | |
648 | ||
649 | error: | |
650 | spin_unlock(&key_serial_lock); | |
651 | return key; | |
652 | ||
653 | } /* end key_lookup() */ | |
654 | ||
655 | /*****************************************************************************/ | |
656 | /* | |
657 | * find and lock the specified key type against removal | |
658 | * - we return with the sem readlocked | |
659 | */ | |
660 | struct key_type *key_type_lookup(const char *type) | |
661 | { | |
662 | struct key_type *ktype; | |
663 | ||
664 | down_read(&key_types_sem); | |
665 | ||
666 | /* look up the key type to see if it's one of the registered kernel | |
667 | * types */ | |
668 | list_for_each_entry(ktype, &key_types_list, link) { | |
669 | if (strcmp(ktype->name, type) == 0) | |
670 | goto found_kernel_type; | |
671 | } | |
672 | ||
673 | up_read(&key_types_sem); | |
674 | ktype = ERR_PTR(-ENOKEY); | |
675 | ||
676 | found_kernel_type: | |
677 | return ktype; | |
678 | ||
679 | } /* end key_type_lookup() */ | |
680 | ||
681 | /*****************************************************************************/ | |
682 | /* | |
683 | * unlock a key type | |
684 | */ | |
685 | void key_type_put(struct key_type *ktype) | |
686 | { | |
687 | up_read(&key_types_sem); | |
688 | ||
689 | } /* end key_type_put() */ | |
690 | ||
691 | /*****************************************************************************/ | |
692 | /* | |
693 | * attempt to update an existing key | |
694 | * - the key has an incremented refcount | |
695 | * - we need to put the key if we get an error | |
696 | */ | |
664cceb0 DH |
697 | static inline key_ref_t __key_update(key_ref_t key_ref, |
698 | const void *payload, size_t plen) | |
1da177e4 | 699 | { |
664cceb0 | 700 | struct key *key = key_ref_to_ptr(key_ref); |
1da177e4 LT |
701 | int ret; |
702 | ||
703 | /* need write permission on the key to update it */ | |
29db9190 DH |
704 | ret = key_permission(key_ref, KEY_WRITE); |
705 | if (ret < 0) | |
1da177e4 LT |
706 | goto error; |
707 | ||
708 | ret = -EEXIST; | |
709 | if (!key->type->update) | |
710 | goto error; | |
711 | ||
712 | down_write(&key->sem); | |
713 | ||
714 | ret = key->type->update(key, payload, plen); | |
76d8aeab | 715 | if (ret == 0) |
1da177e4 | 716 | /* updating a negative key instantiates it */ |
76d8aeab | 717 | clear_bit(KEY_FLAG_NEGATIVE, &key->flags); |
1da177e4 LT |
718 | |
719 | up_write(&key->sem); | |
720 | ||
721 | if (ret < 0) | |
722 | goto error; | |
664cceb0 DH |
723 | out: |
724 | return key_ref; | |
1da177e4 | 725 | |
664cceb0 | 726 | error: |
1da177e4 | 727 | key_put(key); |
664cceb0 | 728 | key_ref = ERR_PTR(ret); |
1da177e4 LT |
729 | goto out; |
730 | ||
731 | } /* end __key_update() */ | |
732 | ||
733 | /*****************************************************************************/ | |
734 | /* | |
735 | * search the specified keyring for a key of the same description; if one is | |
736 | * found, update it, otherwise add a new one | |
737 | */ | |
664cceb0 DH |
738 | key_ref_t key_create_or_update(key_ref_t keyring_ref, |
739 | const char *type, | |
740 | const char *description, | |
741 | const void *payload, | |
742 | size_t plen, | |
6b79ccb5 | 743 | key_perm_t perm, |
7e047ef5 | 744 | unsigned long flags) |
1da177e4 | 745 | { |
d84f4f99 | 746 | const struct cred *cred = current_cred(); |
1da177e4 | 747 | struct key_type *ktype; |
664cceb0 | 748 | struct key *keyring, *key = NULL; |
664cceb0 | 749 | key_ref_t key_ref; |
1da177e4 LT |
750 | int ret; |
751 | ||
1da177e4 LT |
752 | /* look up the key type to see if it's one of the registered kernel |
753 | * types */ | |
754 | ktype = key_type_lookup(type); | |
755 | if (IS_ERR(ktype)) { | |
664cceb0 | 756 | key_ref = ERR_PTR(-ENODEV); |
1da177e4 LT |
757 | goto error; |
758 | } | |
759 | ||
664cceb0 | 760 | key_ref = ERR_PTR(-EINVAL); |
1da177e4 LT |
761 | if (!ktype->match || !ktype->instantiate) |
762 | goto error_2; | |
763 | ||
664cceb0 DH |
764 | keyring = key_ref_to_ptr(keyring_ref); |
765 | ||
766 | key_check(keyring); | |
767 | ||
c3a9d654 DH |
768 | key_ref = ERR_PTR(-ENOTDIR); |
769 | if (keyring->type != &key_type_keyring) | |
770 | goto error_2; | |
771 | ||
664cceb0 DH |
772 | down_write(&keyring->sem); |
773 | ||
774 | /* if we're going to allocate a new key, we're going to have | |
775 | * to modify the keyring */ | |
29db9190 DH |
776 | ret = key_permission(keyring_ref, KEY_WRITE); |
777 | if (ret < 0) { | |
778 | key_ref = ERR_PTR(ret); | |
664cceb0 | 779 | goto error_3; |
29db9190 | 780 | } |
664cceb0 | 781 | |
1d9b7d97 DH |
782 | /* if it's possible to update this type of key, search for an existing |
783 | * key of the same type and description in the destination keyring and | |
784 | * update that instead if possible | |
1da177e4 | 785 | */ |
1d9b7d97 DH |
786 | if (ktype->update) { |
787 | key_ref = __keyring_search_one(keyring_ref, ktype, description, | |
788 | 0); | |
789 | if (!IS_ERR(key_ref)) | |
790 | goto found_matching_key; | |
791 | } | |
1da177e4 | 792 | |
6b79ccb5 AR |
793 | /* if the client doesn't provide, decide on the permissions we want */ |
794 | if (perm == KEY_PERM_UNDEF) { | |
795 | perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR; | |
796 | perm |= KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK | KEY_USR_SETATTR; | |
1da177e4 | 797 | |
6b79ccb5 AR |
798 | if (ktype->read) |
799 | perm |= KEY_POS_READ | KEY_USR_READ; | |
1da177e4 | 800 | |
6b79ccb5 AR |
801 | if (ktype == &key_type_keyring || ktype->update) |
802 | perm |= KEY_USR_WRITE; | |
803 | } | |
1da177e4 LT |
804 | |
805 | /* allocate a new key */ | |
d84f4f99 DH |
806 | key = key_alloc(ktype, description, cred->fsuid, cred->fsgid, cred, |
807 | perm, flags); | |
1da177e4 | 808 | if (IS_ERR(key)) { |
e231c2ee | 809 | key_ref = ERR_CAST(key); |
1da177e4 LT |
810 | goto error_3; |
811 | } | |
812 | ||
813 | /* instantiate it and link it into the target keyring */ | |
3e30148c | 814 | ret = __key_instantiate_and_link(key, payload, plen, keyring, NULL); |
1da177e4 LT |
815 | if (ret < 0) { |
816 | key_put(key); | |
664cceb0 DH |
817 | key_ref = ERR_PTR(ret); |
818 | goto error_3; | |
1da177e4 LT |
819 | } |
820 | ||
664cceb0 DH |
821 | key_ref = make_key_ref(key, is_key_possessed(keyring_ref)); |
822 | ||
1da177e4 LT |
823 | error_3: |
824 | up_write(&keyring->sem); | |
825 | error_2: | |
826 | key_type_put(ktype); | |
827 | error: | |
664cceb0 | 828 | return key_ref; |
1da177e4 LT |
829 | |
830 | found_matching_key: | |
831 | /* we found a matching key, so we're going to try to update it | |
832 | * - we can drop the locks first as we have the key pinned | |
833 | */ | |
834 | up_write(&keyring->sem); | |
835 | key_type_put(ktype); | |
836 | ||
664cceb0 | 837 | key_ref = __key_update(key_ref, payload, plen); |
1da177e4 LT |
838 | goto error; |
839 | ||
840 | } /* end key_create_or_update() */ | |
841 | ||
842 | EXPORT_SYMBOL(key_create_or_update); | |
843 | ||
844 | /*****************************************************************************/ | |
845 | /* | |
846 | * update a key | |
847 | */ | |
664cceb0 | 848 | int key_update(key_ref_t key_ref, const void *payload, size_t plen) |
1da177e4 | 849 | { |
664cceb0 | 850 | struct key *key = key_ref_to_ptr(key_ref); |
1da177e4 LT |
851 | int ret; |
852 | ||
853 | key_check(key); | |
854 | ||
855 | /* the key must be writable */ | |
29db9190 DH |
856 | ret = key_permission(key_ref, KEY_WRITE); |
857 | if (ret < 0) | |
1da177e4 LT |
858 | goto error; |
859 | ||
860 | /* attempt to update it if supported */ | |
861 | ret = -EOPNOTSUPP; | |
862 | if (key->type->update) { | |
863 | down_write(&key->sem); | |
1da177e4 | 864 | |
29db9190 | 865 | ret = key->type->update(key, payload, plen); |
76d8aeab | 866 | if (ret == 0) |
1da177e4 | 867 | /* updating a negative key instantiates it */ |
76d8aeab | 868 | clear_bit(KEY_FLAG_NEGATIVE, &key->flags); |
1da177e4 LT |
869 | |
870 | up_write(&key->sem); | |
871 | } | |
872 | ||
873 | error: | |
874 | return ret; | |
875 | ||
876 | } /* end key_update() */ | |
877 | ||
878 | EXPORT_SYMBOL(key_update); | |
879 | ||
1da177e4 LT |
880 | /*****************************************************************************/ |
881 | /* | |
882 | * revoke a key | |
883 | */ | |
884 | void key_revoke(struct key *key) | |
885 | { | |
886 | key_check(key); | |
887 | ||
76181c13 DH |
888 | /* make sure no one's trying to change or use the key when we mark it |
889 | * - we tell lockdep that we might nest because we might be revoking an | |
890 | * authorisation key whilst holding the sem on a key we've just | |
891 | * instantiated | |
892 | */ | |
893 | down_write_nested(&key->sem, 1); | |
894 | if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags) && | |
895 | key->type->revoke) | |
04c567d9 DH |
896 | key->type->revoke(key); |
897 | ||
1da177e4 LT |
898 | up_write(&key->sem); |
899 | ||
900 | } /* end key_revoke() */ | |
901 | ||
902 | EXPORT_SYMBOL(key_revoke); | |
903 | ||
904 | /*****************************************************************************/ | |
905 | /* | |
906 | * register a type of key | |
907 | */ | |
908 | int register_key_type(struct key_type *ktype) | |
909 | { | |
910 | struct key_type *p; | |
911 | int ret; | |
912 | ||
913 | ret = -EEXIST; | |
914 | down_write(&key_types_sem); | |
915 | ||
916 | /* disallow key types with the same name */ | |
917 | list_for_each_entry(p, &key_types_list, link) { | |
918 | if (strcmp(p->name, ktype->name) == 0) | |
919 | goto out; | |
920 | } | |
921 | ||
922 | /* store the type */ | |
923 | list_add(&ktype->link, &key_types_list); | |
924 | ret = 0; | |
925 | ||
926 | out: | |
927 | up_write(&key_types_sem); | |
928 | return ret; | |
929 | ||
930 | } /* end register_key_type() */ | |
931 | ||
932 | EXPORT_SYMBOL(register_key_type); | |
933 | ||
934 | /*****************************************************************************/ | |
935 | /* | |
936 | * unregister a type of key | |
937 | */ | |
938 | void unregister_key_type(struct key_type *ktype) | |
939 | { | |
940 | struct rb_node *_n; | |
941 | struct key *key; | |
942 | ||
943 | down_write(&key_types_sem); | |
944 | ||
945 | /* withdraw the key type */ | |
946 | list_del_init(&ktype->link); | |
947 | ||
76d8aeab | 948 | /* mark all the keys of this type dead */ |
1da177e4 LT |
949 | spin_lock(&key_serial_lock); |
950 | ||
951 | for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { | |
952 | key = rb_entry(_n, struct key, serial_node); | |
953 | ||
76d8aeab DH |
954 | if (key->type == ktype) |
955 | key->type = &key_type_dead; | |
956 | } | |
957 | ||
958 | spin_unlock(&key_serial_lock); | |
959 | ||
960 | /* make sure everyone revalidates their keys */ | |
b2b18660 | 961 | synchronize_rcu(); |
76d8aeab DH |
962 | |
963 | /* we should now be able to destroy the payloads of all the keys of | |
964 | * this type with impunity */ | |
965 | spin_lock(&key_serial_lock); | |
1da177e4 | 966 | |
76d8aeab DH |
967 | for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { |
968 | key = rb_entry(_n, struct key, serial_node); | |
1da177e4 | 969 | |
76d8aeab DH |
970 | if (key->type == ktype) { |
971 | if (ktype->destroy) | |
972 | ktype->destroy(key); | |
a7807a32 | 973 | memset(&key->payload, KEY_DESTROY, sizeof(key->payload)); |
76d8aeab | 974 | } |
1da177e4 LT |
975 | } |
976 | ||
977 | spin_unlock(&key_serial_lock); | |
978 | up_write(&key_types_sem); | |
979 | ||
980 | } /* end unregister_key_type() */ | |
981 | ||
982 | EXPORT_SYMBOL(unregister_key_type); | |
983 | ||
984 | /*****************************************************************************/ | |
985 | /* | |
986 | * initialise the key management stuff | |
987 | */ | |
988 | void __init key_init(void) | |
989 | { | |
990 | /* allocate a slab in which we can store keys */ | |
991 | key_jar = kmem_cache_create("key_jar", sizeof(struct key), | |
20c2df83 | 992 | 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1da177e4 LT |
993 | |
994 | /* add the special key types */ | |
995 | list_add_tail(&key_type_keyring.link, &key_types_list); | |
996 | list_add_tail(&key_type_dead.link, &key_types_list); | |
997 | list_add_tail(&key_type_user.link, &key_types_list); | |
998 | ||
999 | /* record the root user tracking */ | |
1000 | rb_link_node(&root_key_user.node, | |
1001 | NULL, | |
1002 | &key_user_tree.rb_node); | |
1003 | ||
1004 | rb_insert_color(&root_key_user.node, | |
1005 | &key_user_tree); | |
1006 | ||
1da177e4 | 1007 | } /* end key_init() */ |