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 | 20 | #include <linux/err.h> |
1d1e9756 | 21 | #include <linux/user_namespace.h> |
1da177e4 LT |
22 | #include "internal.h" |
23 | ||
e18b890b | 24 | static struct kmem_cache *key_jar; |
1da177e4 LT |
25 | struct rb_root key_serial_tree; /* tree of keys indexed by serial */ |
26 | DEFINE_SPINLOCK(key_serial_lock); | |
27 | ||
28 | struct rb_root key_user_tree; /* tree of quota records indexed by UID */ | |
29 | DEFINE_SPINLOCK(key_user_lock); | |
30 | ||
0b77f5bf DH |
31 | unsigned int key_quota_root_maxkeys = 200; /* root's key count quota */ |
32 | unsigned int key_quota_root_maxbytes = 20000; /* root's key space quota */ | |
33 | unsigned int key_quota_maxkeys = 200; /* general key count quota */ | |
34 | unsigned int key_quota_maxbytes = 20000; /* general key space quota */ | |
35 | ||
1da177e4 LT |
36 | static LIST_HEAD(key_types_list); |
37 | static DECLARE_RWSEM(key_types_sem); | |
38 | ||
65f27f38 DH |
39 | static void key_cleanup(struct work_struct *work); |
40 | static DECLARE_WORK(key_cleanup_task, key_cleanup); | |
1da177e4 LT |
41 | |
42 | /* we serialise key instantiation and link */ | |
76181c13 | 43 | DEFINE_MUTEX(key_construction_mutex); |
1da177e4 LT |
44 | |
45 | /* any key who's type gets unegistered will be re-typed to this */ | |
1ae8f407 | 46 | static struct key_type key_type_dead = { |
1da177e4 LT |
47 | .name = "dead", |
48 | }; | |
49 | ||
50 | #ifdef KEY_DEBUGGING | |
51 | void __key_check(const struct key *key) | |
52 | { | |
53 | printk("__key_check: key %p {%08x} should be {%08x}\n", | |
54 | key, key->magic, KEY_DEBUG_MAGIC); | |
55 | BUG(); | |
56 | } | |
57 | #endif | |
58 | ||
59 | /*****************************************************************************/ | |
60 | /* | |
61 | * get the key quota record for a user, allocating a new record if one doesn't | |
62 | * already exist | |
63 | */ | |
1d1e9756 | 64 | struct key_user *key_user_lookup(uid_t uid, struct user_namespace *user_ns) |
1da177e4 LT |
65 | { |
66 | struct key_user *candidate = NULL, *user; | |
67 | struct rb_node *parent = NULL; | |
68 | struct rb_node **p; | |
69 | ||
70 | try_again: | |
71 | p = &key_user_tree.rb_node; | |
72 | spin_lock(&key_user_lock); | |
73 | ||
74 | /* search the tree for a user record with a matching UID */ | |
75 | while (*p) { | |
76 | parent = *p; | |
77 | user = rb_entry(parent, struct key_user, node); | |
78 | ||
79 | if (uid < user->uid) | |
80 | p = &(*p)->rb_left; | |
81 | else if (uid > user->uid) | |
82 | p = &(*p)->rb_right; | |
1d1e9756 SH |
83 | else if (user_ns < user->user_ns) |
84 | p = &(*p)->rb_left; | |
85 | else if (user_ns > user->user_ns) | |
86 | p = &(*p)->rb_right; | |
1da177e4 LT |
87 | else |
88 | goto found; | |
89 | } | |
90 | ||
91 | /* if we get here, we failed to find a match in the tree */ | |
92 | if (!candidate) { | |
93 | /* allocate a candidate user record if we don't already have | |
94 | * one */ | |
95 | spin_unlock(&key_user_lock); | |
96 | ||
97 | user = NULL; | |
98 | candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL); | |
99 | if (unlikely(!candidate)) | |
100 | goto out; | |
101 | ||
102 | /* the allocation may have scheduled, so we need to repeat the | |
103 | * search lest someone else added the record whilst we were | |
104 | * asleep */ | |
105 | goto try_again; | |
106 | } | |
107 | ||
108 | /* if we get here, then the user record still hadn't appeared on the | |
109 | * second pass - so we use the candidate record */ | |
110 | atomic_set(&candidate->usage, 1); | |
111 | atomic_set(&candidate->nkeys, 0); | |
112 | atomic_set(&candidate->nikeys, 0); | |
113 | candidate->uid = uid; | |
1d1e9756 | 114 | candidate->user_ns = get_user_ns(user_ns); |
1da177e4 LT |
115 | candidate->qnkeys = 0; |
116 | candidate->qnbytes = 0; | |
117 | spin_lock_init(&candidate->lock); | |
76181c13 | 118 | mutex_init(&candidate->cons_lock); |
1da177e4 LT |
119 | |
120 | rb_link_node(&candidate->node, parent, p); | |
121 | rb_insert_color(&candidate->node, &key_user_tree); | |
122 | spin_unlock(&key_user_lock); | |
123 | user = candidate; | |
124 | goto out; | |
125 | ||
126 | /* okay - we found a user record for this UID */ | |
127 | found: | |
128 | atomic_inc(&user->usage); | |
129 | spin_unlock(&key_user_lock); | |
a7f988ba | 130 | kfree(candidate); |
1da177e4 LT |
131 | out: |
132 | return user; | |
133 | ||
134 | } /* end key_user_lookup() */ | |
135 | ||
136 | /*****************************************************************************/ | |
137 | /* | |
138 | * dispose of a user structure | |
139 | */ | |
140 | void key_user_put(struct key_user *user) | |
141 | { | |
142 | if (atomic_dec_and_lock(&user->usage, &key_user_lock)) { | |
143 | rb_erase(&user->node, &key_user_tree); | |
144 | spin_unlock(&key_user_lock); | |
1d1e9756 | 145 | put_user_ns(user->user_ns); |
1da177e4 LT |
146 | |
147 | kfree(user); | |
148 | } | |
149 | ||
150 | } /* end key_user_put() */ | |
151 | ||
1da177e4 LT |
152 | /*****************************************************************************/ |
153 | /* | |
154 | * assign a key the next unique serial number | |
e51f6d34 ML |
155 | * - these are assigned randomly to avoid security issues through covert |
156 | * channel problems | |
1da177e4 LT |
157 | */ |
158 | static inline void key_alloc_serial(struct key *key) | |
159 | { | |
160 | struct rb_node *parent, **p; | |
161 | struct key *xkey; | |
162 | ||
e51f6d34 | 163 | /* propose a random serial number and look for a hole for it in the |
1da177e4 | 164 | * serial number tree */ |
e51f6d34 ML |
165 | do { |
166 | get_random_bytes(&key->serial, sizeof(key->serial)); | |
167 | ||
168 | key->serial >>= 1; /* negative numbers are not permitted */ | |
169 | } while (key->serial < 3); | |
170 | ||
171 | spin_lock(&key_serial_lock); | |
1da177e4 | 172 | |
9ad0830f | 173 | attempt_insertion: |
1da177e4 LT |
174 | parent = NULL; |
175 | p = &key_serial_tree.rb_node; | |
176 | ||
177 | while (*p) { | |
178 | parent = *p; | |
179 | xkey = rb_entry(parent, struct key, serial_node); | |
180 | ||
181 | if (key->serial < xkey->serial) | |
182 | p = &(*p)->rb_left; | |
183 | else if (key->serial > xkey->serial) | |
184 | p = &(*p)->rb_right; | |
185 | else | |
186 | goto serial_exists; | |
187 | } | |
9ad0830f DH |
188 | |
189 | /* we've found a suitable hole - arrange for this key to occupy it */ | |
190 | rb_link_node(&key->serial_node, parent, p); | |
191 | rb_insert_color(&key->serial_node, &key_serial_tree); | |
192 | ||
193 | spin_unlock(&key_serial_lock); | |
194 | return; | |
1da177e4 LT |
195 | |
196 | /* we found a key with the proposed serial number - walk the tree from | |
197 | * that point looking for the next unused serial number */ | |
e51f6d34 | 198 | serial_exists: |
1da177e4 | 199 | for (;;) { |
e51f6d34 | 200 | key->serial++; |
9ad0830f DH |
201 | if (key->serial < 3) { |
202 | key->serial = 3; | |
203 | goto attempt_insertion; | |
204 | } | |
1da177e4 LT |
205 | |
206 | parent = rb_next(parent); | |
207 | if (!parent) | |
9ad0830f | 208 | goto attempt_insertion; |
1da177e4 LT |
209 | |
210 | xkey = rb_entry(parent, struct key, serial_node); | |
211 | if (key->serial < xkey->serial) | |
9ad0830f | 212 | goto attempt_insertion; |
1da177e4 LT |
213 | } |
214 | ||
1da177e4 LT |
215 | } /* end key_alloc_serial() */ |
216 | ||
217 | /*****************************************************************************/ | |
218 | /* | |
219 | * allocate a key of the specified type | |
220 | * - update the user's quota to reflect the existence of the key | |
8d9067bd DH |
221 | * - called from a key-type operation with key_types_sem read-locked by |
222 | * key_create_or_update() | |
223 | * - this prevents unregistration of the key type | |
1da177e4 LT |
224 | * - upon return the key is as yet uninstantiated; the caller needs to either |
225 | * instantiate the key or discard it before returning | |
226 | */ | |
227 | struct key *key_alloc(struct key_type *type, const char *desc, | |
d84f4f99 | 228 | uid_t uid, gid_t gid, const struct cred *cred, |
7e047ef5 | 229 | key_perm_t perm, unsigned long flags) |
1da177e4 LT |
230 | { |
231 | struct key_user *user = NULL; | |
232 | struct key *key; | |
233 | size_t desclen, quotalen; | |
29db9190 | 234 | int ret; |
1da177e4 LT |
235 | |
236 | key = ERR_PTR(-EINVAL); | |
237 | if (!desc || !*desc) | |
238 | goto error; | |
239 | ||
240 | desclen = strlen(desc) + 1; | |
241 | quotalen = desclen + type->def_datalen; | |
242 | ||
243 | /* get hold of the key tracking for this user */ | |
1d1e9756 | 244 | user = key_user_lookup(uid, cred->user->user_ns); |
1da177e4 LT |
245 | if (!user) |
246 | goto no_memory_1; | |
247 | ||
248 | /* check that the user's quota permits allocation of another key and | |
249 | * its description */ | |
7e047ef5 | 250 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
0b77f5bf DH |
251 | unsigned maxkeys = (uid == 0) ? |
252 | key_quota_root_maxkeys : key_quota_maxkeys; | |
253 | unsigned maxbytes = (uid == 0) ? | |
254 | key_quota_root_maxbytes : key_quota_maxbytes; | |
255 | ||
1da177e4 | 256 | spin_lock(&user->lock); |
7e047ef5 | 257 | if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) { |
0b77f5bf DH |
258 | if (user->qnkeys + 1 >= maxkeys || |
259 | user->qnbytes + quotalen >= maxbytes || | |
260 | user->qnbytes + quotalen < user->qnbytes) | |
7e047ef5 DH |
261 | goto no_quota; |
262 | } | |
1da177e4 LT |
263 | |
264 | user->qnkeys++; | |
265 | user->qnbytes += quotalen; | |
266 | spin_unlock(&user->lock); | |
267 | } | |
268 | ||
269 | /* allocate and initialise the key and its description */ | |
e94b1766 | 270 | key = kmem_cache_alloc(key_jar, GFP_KERNEL); |
1da177e4 LT |
271 | if (!key) |
272 | goto no_memory_2; | |
273 | ||
274 | if (desc) { | |
48ad504e | 275 | key->description = kmemdup(desc, desclen, GFP_KERNEL); |
1da177e4 LT |
276 | if (!key->description) |
277 | goto no_memory_3; | |
1da177e4 LT |
278 | } |
279 | ||
280 | atomic_set(&key->usage, 1); | |
1da177e4 LT |
281 | init_rwsem(&key->sem); |
282 | key->type = type; | |
283 | key->user = user; | |
284 | key->quotalen = quotalen; | |
285 | key->datalen = type->def_datalen; | |
286 | key->uid = uid; | |
287 | key->gid = gid; | |
288 | key->perm = perm; | |
289 | key->flags = 0; | |
290 | key->expiry = 0; | |
291 | key->payload.data = NULL; | |
29db9190 | 292 | key->security = NULL; |
1da177e4 | 293 | |
7e047ef5 | 294 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) |
76d8aeab | 295 | key->flags |= 1 << KEY_FLAG_IN_QUOTA; |
1da177e4 LT |
296 | |
297 | memset(&key->type_data, 0, sizeof(key->type_data)); | |
298 | ||
299 | #ifdef KEY_DEBUGGING | |
300 | key->magic = KEY_DEBUG_MAGIC; | |
301 | #endif | |
302 | ||
29db9190 | 303 | /* let the security module know about the key */ |
d84f4f99 | 304 | ret = security_key_alloc(key, cred, flags); |
29db9190 DH |
305 | if (ret < 0) |
306 | goto security_error; | |
307 | ||
1da177e4 LT |
308 | /* publish the key by giving it a serial number */ |
309 | atomic_inc(&user->nkeys); | |
310 | key_alloc_serial(key); | |
311 | ||
29db9190 | 312 | error: |
1da177e4 LT |
313 | return key; |
314 | ||
29db9190 DH |
315 | security_error: |
316 | kfree(key->description); | |
1da177e4 | 317 | kmem_cache_free(key_jar, key); |
7e047ef5 | 318 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
1da177e4 LT |
319 | spin_lock(&user->lock); |
320 | user->qnkeys--; | |
321 | user->qnbytes -= quotalen; | |
322 | spin_unlock(&user->lock); | |
323 | } | |
324 | key_user_put(user); | |
29db9190 DH |
325 | key = ERR_PTR(ret); |
326 | goto error; | |
327 | ||
328 | no_memory_3: | |
329 | kmem_cache_free(key_jar, key); | |
330 | no_memory_2: | |
7e047ef5 | 331 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
29db9190 DH |
332 | spin_lock(&user->lock); |
333 | user->qnkeys--; | |
334 | user->qnbytes -= quotalen; | |
335 | spin_unlock(&user->lock); | |
336 | } | |
337 | key_user_put(user); | |
338 | no_memory_1: | |
1da177e4 LT |
339 | key = ERR_PTR(-ENOMEM); |
340 | goto error; | |
341 | ||
29db9190 | 342 | no_quota: |
1da177e4 LT |
343 | spin_unlock(&user->lock); |
344 | key_user_put(user); | |
345 | key = ERR_PTR(-EDQUOT); | |
346 | goto error; | |
347 | ||
348 | } /* end key_alloc() */ | |
349 | ||
350 | EXPORT_SYMBOL(key_alloc); | |
351 | ||
352 | /*****************************************************************************/ | |
353 | /* | |
354 | * reserve an amount of quota for the key's payload | |
355 | */ | |
356 | int key_payload_reserve(struct key *key, size_t datalen) | |
357 | { | |
358 | int delta = (int) datalen - key->datalen; | |
359 | int ret = 0; | |
360 | ||
361 | key_check(key); | |
362 | ||
363 | /* contemplate the quota adjustment */ | |
76d8aeab | 364 | if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { |
0b77f5bf DH |
365 | unsigned maxbytes = (key->user->uid == 0) ? |
366 | key_quota_root_maxbytes : key_quota_maxbytes; | |
367 | ||
1da177e4 LT |
368 | spin_lock(&key->user->lock); |
369 | ||
370 | if (delta > 0 && | |
0b77f5bf DH |
371 | (key->user->qnbytes + delta >= maxbytes || |
372 | key->user->qnbytes + delta < key->user->qnbytes)) { | |
1da177e4 LT |
373 | ret = -EDQUOT; |
374 | } | |
375 | else { | |
376 | key->user->qnbytes += delta; | |
377 | key->quotalen += delta; | |
378 | } | |
379 | spin_unlock(&key->user->lock); | |
380 | } | |
381 | ||
382 | /* change the recorded data length if that didn't generate an error */ | |
383 | if (ret == 0) | |
384 | key->datalen = datalen; | |
385 | ||
386 | return ret; | |
387 | ||
388 | } /* end key_payload_reserve() */ | |
389 | ||
390 | EXPORT_SYMBOL(key_payload_reserve); | |
391 | ||
392 | /*****************************************************************************/ | |
393 | /* | |
394 | * instantiate a key and link it into the target keyring atomically | |
395 | * - called with the target keyring's semaphore writelocked | |
396 | */ | |
397 | static int __key_instantiate_and_link(struct key *key, | |
398 | const void *data, | |
399 | size_t datalen, | |
3e30148c | 400 | struct key *keyring, |
d84f4f99 | 401 | struct key *authkey) |
1da177e4 LT |
402 | { |
403 | int ret, awaken; | |
404 | ||
405 | key_check(key); | |
406 | key_check(keyring); | |
407 | ||
408 | awaken = 0; | |
409 | ret = -EBUSY; | |
410 | ||
76181c13 | 411 | mutex_lock(&key_construction_mutex); |
1da177e4 LT |
412 | |
413 | /* can't instantiate twice */ | |
76d8aeab | 414 | if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { |
1da177e4 LT |
415 | /* instantiate the key */ |
416 | ret = key->type->instantiate(key, data, datalen); | |
417 | ||
418 | if (ret == 0) { | |
419 | /* mark the key as being instantiated */ | |
1da177e4 | 420 | atomic_inc(&key->user->nikeys); |
76d8aeab | 421 | set_bit(KEY_FLAG_INSTANTIATED, &key->flags); |
1da177e4 | 422 | |
76d8aeab | 423 | if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) |
1da177e4 | 424 | awaken = 1; |
1da177e4 LT |
425 | |
426 | /* and link it into the destination keyring */ | |
427 | if (keyring) | |
428 | ret = __key_link(keyring, key); | |
3e30148c DH |
429 | |
430 | /* disable the authorisation key */ | |
d84f4f99 DH |
431 | if (authkey) |
432 | key_revoke(authkey); | |
1da177e4 LT |
433 | } |
434 | } | |
435 | ||
76181c13 | 436 | mutex_unlock(&key_construction_mutex); |
1da177e4 LT |
437 | |
438 | /* wake up anyone waiting for a key to be constructed */ | |
439 | if (awaken) | |
76181c13 | 440 | wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT); |
1da177e4 LT |
441 | |
442 | return ret; | |
443 | ||
444 | } /* end __key_instantiate_and_link() */ | |
445 | ||
446 | /*****************************************************************************/ | |
447 | /* | |
448 | * instantiate a key and link it into the target keyring atomically | |
449 | */ | |
450 | int key_instantiate_and_link(struct key *key, | |
451 | const void *data, | |
452 | size_t datalen, | |
3e30148c | 453 | struct key *keyring, |
d84f4f99 | 454 | struct key *authkey) |
1da177e4 LT |
455 | { |
456 | int ret; | |
457 | ||
458 | if (keyring) | |
459 | down_write(&keyring->sem); | |
460 | ||
d84f4f99 | 461 | ret = __key_instantiate_and_link(key, data, datalen, keyring, authkey); |
1da177e4 LT |
462 | |
463 | if (keyring) | |
464 | up_write(&keyring->sem); | |
465 | ||
466 | return ret; | |
3e30148c | 467 | |
1da177e4 LT |
468 | } /* end key_instantiate_and_link() */ |
469 | ||
470 | EXPORT_SYMBOL(key_instantiate_and_link); | |
471 | ||
472 | /*****************************************************************************/ | |
473 | /* | |
474 | * negatively instantiate a key and link it into the target keyring atomically | |
475 | */ | |
476 | int key_negate_and_link(struct key *key, | |
477 | unsigned timeout, | |
3e30148c | 478 | struct key *keyring, |
d84f4f99 | 479 | struct key *authkey) |
1da177e4 LT |
480 | { |
481 | struct timespec now; | |
482 | int ret, awaken; | |
483 | ||
484 | key_check(key); | |
485 | key_check(keyring); | |
486 | ||
487 | awaken = 0; | |
488 | ret = -EBUSY; | |
489 | ||
490 | if (keyring) | |
491 | down_write(&keyring->sem); | |
492 | ||
76181c13 | 493 | mutex_lock(&key_construction_mutex); |
1da177e4 LT |
494 | |
495 | /* can't instantiate twice */ | |
76d8aeab | 496 | if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { |
1da177e4 | 497 | /* mark the key as being negatively instantiated */ |
1da177e4 | 498 | atomic_inc(&key->user->nikeys); |
76d8aeab DH |
499 | set_bit(KEY_FLAG_NEGATIVE, &key->flags); |
500 | set_bit(KEY_FLAG_INSTANTIATED, &key->flags); | |
1da177e4 LT |
501 | now = current_kernel_time(); |
502 | key->expiry = now.tv_sec + timeout; | |
c08ef808 | 503 | key_schedule_gc(key->expiry + key_gc_delay); |
1da177e4 | 504 | |
76d8aeab | 505 | if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) |
1da177e4 | 506 | awaken = 1; |
1da177e4 | 507 | |
1da177e4 LT |
508 | ret = 0; |
509 | ||
510 | /* and link it into the destination keyring */ | |
511 | if (keyring) | |
512 | ret = __key_link(keyring, key); | |
3e30148c DH |
513 | |
514 | /* disable the authorisation key */ | |
d84f4f99 DH |
515 | if (authkey) |
516 | key_revoke(authkey); | |
1da177e4 LT |
517 | } |
518 | ||
76181c13 | 519 | mutex_unlock(&key_construction_mutex); |
1da177e4 LT |
520 | |
521 | if (keyring) | |
522 | up_write(&keyring->sem); | |
523 | ||
524 | /* wake up anyone waiting for a key to be constructed */ | |
525 | if (awaken) | |
76181c13 | 526 | wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT); |
1da177e4 LT |
527 | |
528 | return ret; | |
529 | ||
530 | } /* end key_negate_and_link() */ | |
531 | ||
532 | EXPORT_SYMBOL(key_negate_and_link); | |
533 | ||
534 | /*****************************************************************************/ | |
535 | /* | |
536 | * do cleaning up in process context so that we don't have to disable | |
537 | * interrupts all over the place | |
538 | */ | |
65f27f38 | 539 | static void key_cleanup(struct work_struct *work) |
1da177e4 LT |
540 | { |
541 | struct rb_node *_n; | |
542 | struct key *key; | |
543 | ||
544 | go_again: | |
545 | /* look for a dead key in the tree */ | |
546 | spin_lock(&key_serial_lock); | |
547 | ||
548 | for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { | |
549 | key = rb_entry(_n, struct key, serial_node); | |
550 | ||
551 | if (atomic_read(&key->usage) == 0) | |
552 | goto found_dead_key; | |
553 | } | |
554 | ||
555 | spin_unlock(&key_serial_lock); | |
556 | return; | |
557 | ||
558 | found_dead_key: | |
559 | /* we found a dead key - once we've removed it from the tree, we can | |
560 | * drop the lock */ | |
561 | rb_erase(&key->serial_node, &key_serial_tree); | |
562 | spin_unlock(&key_serial_lock); | |
563 | ||
76d8aeab DH |
564 | key_check(key); |
565 | ||
29db9190 DH |
566 | security_key_free(key); |
567 | ||
1da177e4 | 568 | /* deal with the user's key tracking and quota */ |
76d8aeab | 569 | if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { |
1da177e4 LT |
570 | spin_lock(&key->user->lock); |
571 | key->user->qnkeys--; | |
572 | key->user->qnbytes -= key->quotalen; | |
573 | spin_unlock(&key->user->lock); | |
574 | } | |
575 | ||
576 | atomic_dec(&key->user->nkeys); | |
76d8aeab | 577 | if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) |
1da177e4 LT |
578 | atomic_dec(&key->user->nikeys); |
579 | ||
580 | key_user_put(key->user); | |
581 | ||
582 | /* now throw away the key memory */ | |
583 | if (key->type->destroy) | |
584 | key->type->destroy(key); | |
585 | ||
586 | kfree(key->description); | |
587 | ||
588 | #ifdef KEY_DEBUGGING | |
589 | key->magic = KEY_DEBUG_MAGIC_X; | |
590 | #endif | |
591 | kmem_cache_free(key_jar, key); | |
592 | ||
593 | /* there may, of course, be more than one key to destroy */ | |
594 | goto go_again; | |
595 | ||
596 | } /* end key_cleanup() */ | |
597 | ||
598 | /*****************************************************************************/ | |
599 | /* | |
600 | * dispose of a reference to a key | |
601 | * - when all the references are gone, we schedule the cleanup task to come and | |
602 | * pull it out of the tree in definite process context | |
603 | */ | |
604 | void key_put(struct key *key) | |
605 | { | |
606 | if (key) { | |
607 | key_check(key); | |
608 | ||
609 | if (atomic_dec_and_test(&key->usage)) | |
610 | schedule_work(&key_cleanup_task); | |
611 | } | |
612 | ||
613 | } /* end key_put() */ | |
614 | ||
615 | EXPORT_SYMBOL(key_put); | |
616 | ||
617 | /*****************************************************************************/ | |
618 | /* | |
619 | * find a key by its serial number | |
620 | */ | |
621 | struct key *key_lookup(key_serial_t id) | |
622 | { | |
623 | struct rb_node *n; | |
624 | struct key *key; | |
625 | ||
626 | spin_lock(&key_serial_lock); | |
627 | ||
628 | /* search the tree for the specified key */ | |
629 | n = key_serial_tree.rb_node; | |
630 | while (n) { | |
631 | key = rb_entry(n, struct key, serial_node); | |
632 | ||
633 | if (id < key->serial) | |
634 | n = n->rb_left; | |
635 | else if (id > key->serial) | |
636 | n = n->rb_right; | |
637 | else | |
638 | goto found; | |
639 | } | |
640 | ||
641 | not_found: | |
642 | key = ERR_PTR(-ENOKEY); | |
643 | goto error; | |
644 | ||
645 | found: | |
5593122e DH |
646 | /* pretend it doesn't exist if it is awaiting deletion */ |
647 | if (atomic_read(&key->usage) == 0) | |
1da177e4 LT |
648 | goto not_found; |
649 | ||
650 | /* this races with key_put(), but that doesn't matter since key_put() | |
651 | * doesn't actually change the key | |
652 | */ | |
653 | atomic_inc(&key->usage); | |
654 | ||
655 | error: | |
656 | spin_unlock(&key_serial_lock); | |
657 | return key; | |
658 | ||
659 | } /* end key_lookup() */ | |
660 | ||
661 | /*****************************************************************************/ | |
662 | /* | |
663 | * find and lock the specified key type against removal | |
664 | * - we return with the sem readlocked | |
665 | */ | |
666 | struct key_type *key_type_lookup(const char *type) | |
667 | { | |
668 | struct key_type *ktype; | |
669 | ||
670 | down_read(&key_types_sem); | |
671 | ||
672 | /* look up the key type to see if it's one of the registered kernel | |
673 | * types */ | |
674 | list_for_each_entry(ktype, &key_types_list, link) { | |
675 | if (strcmp(ktype->name, type) == 0) | |
676 | goto found_kernel_type; | |
677 | } | |
678 | ||
679 | up_read(&key_types_sem); | |
680 | ktype = ERR_PTR(-ENOKEY); | |
681 | ||
682 | found_kernel_type: | |
683 | return ktype; | |
684 | ||
685 | } /* end key_type_lookup() */ | |
686 | ||
687 | /*****************************************************************************/ | |
688 | /* | |
689 | * unlock a key type | |
690 | */ | |
691 | void key_type_put(struct key_type *ktype) | |
692 | { | |
693 | up_read(&key_types_sem); | |
694 | ||
695 | } /* end key_type_put() */ | |
696 | ||
697 | /*****************************************************************************/ | |
698 | /* | |
699 | * attempt to update an existing key | |
700 | * - the key has an incremented refcount | |
701 | * - we need to put the key if we get an error | |
702 | */ | |
664cceb0 DH |
703 | static inline key_ref_t __key_update(key_ref_t key_ref, |
704 | const void *payload, size_t plen) | |
1da177e4 | 705 | { |
664cceb0 | 706 | struct key *key = key_ref_to_ptr(key_ref); |
1da177e4 LT |
707 | int ret; |
708 | ||
709 | /* need write permission on the key to update it */ | |
29db9190 DH |
710 | ret = key_permission(key_ref, KEY_WRITE); |
711 | if (ret < 0) | |
1da177e4 LT |
712 | goto error; |
713 | ||
714 | ret = -EEXIST; | |
715 | if (!key->type->update) | |
716 | goto error; | |
717 | ||
718 | down_write(&key->sem); | |
719 | ||
720 | ret = key->type->update(key, payload, plen); | |
76d8aeab | 721 | if (ret == 0) |
1da177e4 | 722 | /* updating a negative key instantiates it */ |
76d8aeab | 723 | clear_bit(KEY_FLAG_NEGATIVE, &key->flags); |
1da177e4 LT |
724 | |
725 | up_write(&key->sem); | |
726 | ||
727 | if (ret < 0) | |
728 | goto error; | |
664cceb0 DH |
729 | out: |
730 | return key_ref; | |
1da177e4 | 731 | |
664cceb0 | 732 | error: |
1da177e4 | 733 | key_put(key); |
664cceb0 | 734 | key_ref = ERR_PTR(ret); |
1da177e4 LT |
735 | goto out; |
736 | ||
737 | } /* end __key_update() */ | |
738 | ||
739 | /*****************************************************************************/ | |
740 | /* | |
741 | * search the specified keyring for a key of the same description; if one is | |
742 | * found, update it, otherwise add a new one | |
743 | */ | |
664cceb0 DH |
744 | key_ref_t key_create_or_update(key_ref_t keyring_ref, |
745 | const char *type, | |
746 | const char *description, | |
747 | const void *payload, | |
748 | size_t plen, | |
6b79ccb5 | 749 | key_perm_t perm, |
7e047ef5 | 750 | unsigned long flags) |
1da177e4 | 751 | { |
d84f4f99 | 752 | const struct cred *cred = current_cred(); |
1da177e4 | 753 | struct key_type *ktype; |
664cceb0 | 754 | struct key *keyring, *key = NULL; |
664cceb0 | 755 | key_ref_t key_ref; |
1da177e4 LT |
756 | int ret; |
757 | ||
1da177e4 LT |
758 | /* look up the key type to see if it's one of the registered kernel |
759 | * types */ | |
760 | ktype = key_type_lookup(type); | |
761 | if (IS_ERR(ktype)) { | |
664cceb0 | 762 | key_ref = ERR_PTR(-ENODEV); |
1da177e4 LT |
763 | goto error; |
764 | } | |
765 | ||
664cceb0 | 766 | key_ref = ERR_PTR(-EINVAL); |
1da177e4 LT |
767 | if (!ktype->match || !ktype->instantiate) |
768 | goto error_2; | |
769 | ||
664cceb0 DH |
770 | keyring = key_ref_to_ptr(keyring_ref); |
771 | ||
772 | key_check(keyring); | |
773 | ||
c3a9d654 DH |
774 | key_ref = ERR_PTR(-ENOTDIR); |
775 | if (keyring->type != &key_type_keyring) | |
776 | goto error_2; | |
777 | ||
664cceb0 DH |
778 | down_write(&keyring->sem); |
779 | ||
780 | /* if we're going to allocate a new key, we're going to have | |
781 | * to modify the keyring */ | |
29db9190 DH |
782 | ret = key_permission(keyring_ref, KEY_WRITE); |
783 | if (ret < 0) { | |
784 | key_ref = ERR_PTR(ret); | |
664cceb0 | 785 | goto error_3; |
29db9190 | 786 | } |
664cceb0 | 787 | |
1d9b7d97 DH |
788 | /* if it's possible to update this type of key, search for an existing |
789 | * key of the same type and description in the destination keyring and | |
790 | * update that instead if possible | |
1da177e4 | 791 | */ |
1d9b7d97 DH |
792 | if (ktype->update) { |
793 | key_ref = __keyring_search_one(keyring_ref, ktype, description, | |
794 | 0); | |
795 | if (!IS_ERR(key_ref)) | |
796 | goto found_matching_key; | |
797 | } | |
1da177e4 | 798 | |
6b79ccb5 AR |
799 | /* if the client doesn't provide, decide on the permissions we want */ |
800 | if (perm == KEY_PERM_UNDEF) { | |
801 | perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR; | |
802 | perm |= KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK | KEY_USR_SETATTR; | |
1da177e4 | 803 | |
6b79ccb5 AR |
804 | if (ktype->read) |
805 | perm |= KEY_POS_READ | KEY_USR_READ; | |
1da177e4 | 806 | |
6b79ccb5 AR |
807 | if (ktype == &key_type_keyring || ktype->update) |
808 | perm |= KEY_USR_WRITE; | |
809 | } | |
1da177e4 LT |
810 | |
811 | /* allocate a new key */ | |
d84f4f99 DH |
812 | key = key_alloc(ktype, description, cred->fsuid, cred->fsgid, cred, |
813 | perm, flags); | |
1da177e4 | 814 | if (IS_ERR(key)) { |
e231c2ee | 815 | key_ref = ERR_CAST(key); |
1da177e4 LT |
816 | goto error_3; |
817 | } | |
818 | ||
819 | /* instantiate it and link it into the target keyring */ | |
3e30148c | 820 | ret = __key_instantiate_and_link(key, payload, plen, keyring, NULL); |
1da177e4 LT |
821 | if (ret < 0) { |
822 | key_put(key); | |
664cceb0 DH |
823 | key_ref = ERR_PTR(ret); |
824 | goto error_3; | |
1da177e4 LT |
825 | } |
826 | ||
664cceb0 DH |
827 | key_ref = make_key_ref(key, is_key_possessed(keyring_ref)); |
828 | ||
1da177e4 LT |
829 | error_3: |
830 | up_write(&keyring->sem); | |
831 | error_2: | |
832 | key_type_put(ktype); | |
833 | error: | |
664cceb0 | 834 | return key_ref; |
1da177e4 LT |
835 | |
836 | found_matching_key: | |
837 | /* we found a matching key, so we're going to try to update it | |
838 | * - we can drop the locks first as we have the key pinned | |
839 | */ | |
840 | up_write(&keyring->sem); | |
841 | key_type_put(ktype); | |
842 | ||
664cceb0 | 843 | key_ref = __key_update(key_ref, payload, plen); |
1da177e4 LT |
844 | goto error; |
845 | ||
846 | } /* end key_create_or_update() */ | |
847 | ||
848 | EXPORT_SYMBOL(key_create_or_update); | |
849 | ||
850 | /*****************************************************************************/ | |
851 | /* | |
852 | * update a key | |
853 | */ | |
664cceb0 | 854 | int key_update(key_ref_t key_ref, const void *payload, size_t plen) |
1da177e4 | 855 | { |
664cceb0 | 856 | struct key *key = key_ref_to_ptr(key_ref); |
1da177e4 LT |
857 | int ret; |
858 | ||
859 | key_check(key); | |
860 | ||
861 | /* the key must be writable */ | |
29db9190 DH |
862 | ret = key_permission(key_ref, KEY_WRITE); |
863 | if (ret < 0) | |
1da177e4 LT |
864 | goto error; |
865 | ||
866 | /* attempt to update it if supported */ | |
867 | ret = -EOPNOTSUPP; | |
868 | if (key->type->update) { | |
869 | down_write(&key->sem); | |
1da177e4 | 870 | |
29db9190 | 871 | ret = key->type->update(key, payload, plen); |
76d8aeab | 872 | if (ret == 0) |
1da177e4 | 873 | /* updating a negative key instantiates it */ |
76d8aeab | 874 | clear_bit(KEY_FLAG_NEGATIVE, &key->flags); |
1da177e4 LT |
875 | |
876 | up_write(&key->sem); | |
877 | } | |
878 | ||
879 | error: | |
880 | return ret; | |
881 | ||
882 | } /* end key_update() */ | |
883 | ||
884 | EXPORT_SYMBOL(key_update); | |
885 | ||
1da177e4 LT |
886 | /*****************************************************************************/ |
887 | /* | |
888 | * revoke a key | |
889 | */ | |
890 | void key_revoke(struct key *key) | |
891 | { | |
5d135440 DH |
892 | struct timespec now; |
893 | time_t time; | |
894 | ||
1da177e4 LT |
895 | key_check(key); |
896 | ||
76181c13 DH |
897 | /* make sure no one's trying to change or use the key when we mark it |
898 | * - we tell lockdep that we might nest because we might be revoking an | |
899 | * authorisation key whilst holding the sem on a key we've just | |
900 | * instantiated | |
901 | */ | |
902 | down_write_nested(&key->sem, 1); | |
903 | if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags) && | |
904 | key->type->revoke) | |
04c567d9 DH |
905 | key->type->revoke(key); |
906 | ||
5d135440 DH |
907 | /* set the death time to no more than the expiry time */ |
908 | now = current_kernel_time(); | |
909 | time = now.tv_sec; | |
910 | if (key->revoked_at == 0 || key->revoked_at > time) { | |
911 | key->revoked_at = time; | |
c08ef808 | 912 | key_schedule_gc(key->revoked_at + key_gc_delay); |
5d135440 DH |
913 | } |
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 | ||
f041ae2f | 971 | if (key->type == ktype) { |
76d8aeab | 972 | key->type = &key_type_dead; |
f041ae2f DH |
973 | set_bit(KEY_FLAG_DEAD, &key->flags); |
974 | } | |
76d8aeab DH |
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 | ||
5d135440 DH |
999 | key_schedule_gc(0); |
1000 | ||
1da177e4 LT |
1001 | } /* end unregister_key_type() */ |
1002 | ||
1003 | EXPORT_SYMBOL(unregister_key_type); | |
1004 | ||
1005 | /*****************************************************************************/ | |
1006 | /* | |
1007 | * initialise the key management stuff | |
1008 | */ | |
1009 | void __init key_init(void) | |
1010 | { | |
1011 | /* allocate a slab in which we can store keys */ | |
1012 | key_jar = kmem_cache_create("key_jar", sizeof(struct key), | |
20c2df83 | 1013 | 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1da177e4 LT |
1014 | |
1015 | /* add the special key types */ | |
1016 | list_add_tail(&key_type_keyring.link, &key_types_list); | |
1017 | list_add_tail(&key_type_dead.link, &key_types_list); | |
1018 | list_add_tail(&key_type_user.link, &key_types_list); | |
1019 | ||
1020 | /* record the root user tracking */ | |
1021 | rb_link_node(&root_key_user.node, | |
1022 | NULL, | |
1023 | &key_user_tree.rb_node); | |
1024 | ||
1025 | rb_insert_color(&root_key_user.node, | |
1026 | &key_user_tree); | |
1027 | ||
1da177e4 | 1028 | } /* end key_init() */ |