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 | ||
8bc16dea | 23 | 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 | ||
973c9f4f | 38 | /* We serialise key instantiation and link */ |
76181c13 | 39 | DEFINE_MUTEX(key_construction_mutex); |
1da177e4 | 40 | |
1da177e4 LT |
41 | #ifdef KEY_DEBUGGING |
42 | void __key_check(const struct key *key) | |
43 | { | |
44 | printk("__key_check: key %p {%08x} should be {%08x}\n", | |
45 | key, key->magic, KEY_DEBUG_MAGIC); | |
46 | BUG(); | |
47 | } | |
48 | #endif | |
49 | ||
1da177e4 | 50 | /* |
973c9f4f DH |
51 | * Get the key quota record for a user, allocating a new record if one doesn't |
52 | * already exist. | |
1da177e4 | 53 | */ |
9a56c2db | 54 | struct key_user *key_user_lookup(kuid_t uid) |
1da177e4 LT |
55 | { |
56 | struct key_user *candidate = NULL, *user; | |
57 | struct rb_node *parent = NULL; | |
58 | struct rb_node **p; | |
59 | ||
973c9f4f | 60 | try_again: |
1da177e4 LT |
61 | p = &key_user_tree.rb_node; |
62 | spin_lock(&key_user_lock); | |
63 | ||
64 | /* search the tree for a user record with a matching UID */ | |
65 | while (*p) { | |
66 | parent = *p; | |
67 | user = rb_entry(parent, struct key_user, node); | |
68 | ||
9a56c2db | 69 | if (uid_lt(uid, user->uid)) |
1da177e4 | 70 | p = &(*p)->rb_left; |
9a56c2db | 71 | else if (uid_gt(uid, user->uid)) |
1d1e9756 | 72 | p = &(*p)->rb_right; |
1da177e4 LT |
73 | else |
74 | goto found; | |
75 | } | |
76 | ||
77 | /* if we get here, we failed to find a match in the tree */ | |
78 | if (!candidate) { | |
79 | /* allocate a candidate user record if we don't already have | |
80 | * one */ | |
81 | spin_unlock(&key_user_lock); | |
82 | ||
83 | user = NULL; | |
84 | candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL); | |
85 | if (unlikely(!candidate)) | |
86 | goto out; | |
87 | ||
88 | /* the allocation may have scheduled, so we need to repeat the | |
89 | * search lest someone else added the record whilst we were | |
90 | * asleep */ | |
91 | goto try_again; | |
92 | } | |
93 | ||
94 | /* if we get here, then the user record still hadn't appeared on the | |
95 | * second pass - so we use the candidate record */ | |
96 | atomic_set(&candidate->usage, 1); | |
97 | atomic_set(&candidate->nkeys, 0); | |
98 | atomic_set(&candidate->nikeys, 0); | |
99 | candidate->uid = uid; | |
100 | candidate->qnkeys = 0; | |
101 | candidate->qnbytes = 0; | |
102 | spin_lock_init(&candidate->lock); | |
76181c13 | 103 | mutex_init(&candidate->cons_lock); |
1da177e4 LT |
104 | |
105 | rb_link_node(&candidate->node, parent, p); | |
106 | rb_insert_color(&candidate->node, &key_user_tree); | |
107 | spin_unlock(&key_user_lock); | |
108 | user = candidate; | |
109 | goto out; | |
110 | ||
111 | /* okay - we found a user record for this UID */ | |
973c9f4f | 112 | found: |
1da177e4 LT |
113 | atomic_inc(&user->usage); |
114 | spin_unlock(&key_user_lock); | |
a7f988ba | 115 | kfree(candidate); |
973c9f4f | 116 | out: |
1da177e4 | 117 | return user; |
a8b17ed0 | 118 | } |
1da177e4 | 119 | |
1da177e4 | 120 | /* |
973c9f4f | 121 | * Dispose of a user structure |
1da177e4 LT |
122 | */ |
123 | void key_user_put(struct key_user *user) | |
124 | { | |
125 | if (atomic_dec_and_lock(&user->usage, &key_user_lock)) { | |
126 | rb_erase(&user->node, &key_user_tree); | |
127 | spin_unlock(&key_user_lock); | |
128 | ||
129 | kfree(user); | |
130 | } | |
a8b17ed0 | 131 | } |
1da177e4 | 132 | |
1da177e4 | 133 | /* |
973c9f4f DH |
134 | * Allocate a serial number for a key. These are assigned randomly to avoid |
135 | * security issues through covert channel problems. | |
1da177e4 LT |
136 | */ |
137 | static inline void key_alloc_serial(struct key *key) | |
138 | { | |
139 | struct rb_node *parent, **p; | |
140 | struct key *xkey; | |
141 | ||
e51f6d34 | 142 | /* propose a random serial number and look for a hole for it in the |
1da177e4 | 143 | * serial number tree */ |
e51f6d34 ML |
144 | do { |
145 | get_random_bytes(&key->serial, sizeof(key->serial)); | |
146 | ||
147 | key->serial >>= 1; /* negative numbers are not permitted */ | |
148 | } while (key->serial < 3); | |
149 | ||
150 | spin_lock(&key_serial_lock); | |
1da177e4 | 151 | |
9ad0830f | 152 | attempt_insertion: |
1da177e4 LT |
153 | parent = NULL; |
154 | p = &key_serial_tree.rb_node; | |
155 | ||
156 | while (*p) { | |
157 | parent = *p; | |
158 | xkey = rb_entry(parent, struct key, serial_node); | |
159 | ||
160 | if (key->serial < xkey->serial) | |
161 | p = &(*p)->rb_left; | |
162 | else if (key->serial > xkey->serial) | |
163 | p = &(*p)->rb_right; | |
164 | else | |
165 | goto serial_exists; | |
166 | } | |
9ad0830f DH |
167 | |
168 | /* we've found a suitable hole - arrange for this key to occupy it */ | |
169 | rb_link_node(&key->serial_node, parent, p); | |
170 | rb_insert_color(&key->serial_node, &key_serial_tree); | |
171 | ||
172 | spin_unlock(&key_serial_lock); | |
173 | return; | |
1da177e4 LT |
174 | |
175 | /* we found a key with the proposed serial number - walk the tree from | |
176 | * that point looking for the next unused serial number */ | |
e51f6d34 | 177 | serial_exists: |
1da177e4 | 178 | for (;;) { |
e51f6d34 | 179 | key->serial++; |
9ad0830f DH |
180 | if (key->serial < 3) { |
181 | key->serial = 3; | |
182 | goto attempt_insertion; | |
183 | } | |
1da177e4 LT |
184 | |
185 | parent = rb_next(parent); | |
186 | if (!parent) | |
9ad0830f | 187 | goto attempt_insertion; |
1da177e4 LT |
188 | |
189 | xkey = rb_entry(parent, struct key, serial_node); | |
190 | if (key->serial < xkey->serial) | |
9ad0830f | 191 | goto attempt_insertion; |
1da177e4 | 192 | } |
a8b17ed0 | 193 | } |
1da177e4 | 194 | |
973c9f4f DH |
195 | /** |
196 | * key_alloc - Allocate a key of the specified type. | |
197 | * @type: The type of key to allocate. | |
198 | * @desc: The key description to allow the key to be searched out. | |
199 | * @uid: The owner of the new key. | |
200 | * @gid: The group ID for the new key's group permissions. | |
201 | * @cred: The credentials specifying UID namespace. | |
202 | * @perm: The permissions mask of the new key. | |
203 | * @flags: Flags specifying quota properties. | |
204 | * | |
205 | * Allocate a key of the specified type with the attributes given. The key is | |
206 | * returned in an uninstantiated state and the caller needs to instantiate the | |
207 | * key before returning. | |
208 | * | |
209 | * The user's key count quota is updated to reflect the creation of the key and | |
210 | * the user's key data quota has the default for the key type reserved. The | |
211 | * instantiation function should amend this as necessary. If insufficient | |
212 | * quota is available, -EDQUOT will be returned. | |
213 | * | |
214 | * The LSM security modules can prevent a key being created, in which case | |
215 | * -EACCES will be returned. | |
216 | * | |
217 | * Returns a pointer to the new key if successful and an error code otherwise. | |
218 | * | |
219 | * Note that the caller needs to ensure the key type isn't uninstantiated. | |
220 | * Internally this can be done by locking key_types_sem. Externally, this can | |
221 | * be done by either never unregistering the key type, or making sure | |
222 | * key_alloc() calls don't race with module unloading. | |
1da177e4 LT |
223 | */ |
224 | struct key *key_alloc(struct key_type *type, const char *desc, | |
9a56c2db | 225 | kuid_t uid, kgid_t gid, const struct cred *cred, |
7e047ef5 | 226 | key_perm_t perm, unsigned long flags) |
1da177e4 LT |
227 | { |
228 | struct key_user *user = NULL; | |
229 | struct key *key; | |
230 | size_t desclen, quotalen; | |
29db9190 | 231 | int ret; |
1da177e4 LT |
232 | |
233 | key = ERR_PTR(-EINVAL); | |
234 | if (!desc || !*desc) | |
235 | goto error; | |
236 | ||
b9fffa38 DH |
237 | if (type->vet_description) { |
238 | ret = type->vet_description(desc); | |
239 | if (ret < 0) { | |
240 | key = ERR_PTR(ret); | |
241 | goto error; | |
242 | } | |
243 | } | |
244 | ||
1da177e4 LT |
245 | desclen = strlen(desc) + 1; |
246 | quotalen = desclen + type->def_datalen; | |
247 | ||
248 | /* get hold of the key tracking for this user */ | |
9a56c2db | 249 | user = key_user_lookup(uid); |
1da177e4 LT |
250 | if (!user) |
251 | goto no_memory_1; | |
252 | ||
253 | /* check that the user's quota permits allocation of another key and | |
254 | * its description */ | |
7e047ef5 | 255 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
9a56c2db | 256 | unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ? |
0b77f5bf | 257 | key_quota_root_maxkeys : key_quota_maxkeys; |
9a56c2db | 258 | unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ? |
0b77f5bf DH |
259 | key_quota_root_maxbytes : key_quota_maxbytes; |
260 | ||
1da177e4 | 261 | spin_lock(&user->lock); |
7e047ef5 | 262 | if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) { |
0b77f5bf DH |
263 | if (user->qnkeys + 1 >= maxkeys || |
264 | user->qnbytes + quotalen >= maxbytes || | |
265 | user->qnbytes + quotalen < user->qnbytes) | |
7e047ef5 DH |
266 | goto no_quota; |
267 | } | |
1da177e4 LT |
268 | |
269 | user->qnkeys++; | |
270 | user->qnbytes += quotalen; | |
271 | spin_unlock(&user->lock); | |
272 | } | |
273 | ||
274 | /* allocate and initialise the key and its description */ | |
e94b1766 | 275 | key = kmem_cache_alloc(key_jar, GFP_KERNEL); |
1da177e4 LT |
276 | if (!key) |
277 | goto no_memory_2; | |
278 | ||
279 | if (desc) { | |
48ad504e | 280 | key->description = kmemdup(desc, desclen, GFP_KERNEL); |
1da177e4 LT |
281 | if (!key->description) |
282 | goto no_memory_3; | |
1da177e4 LT |
283 | } |
284 | ||
285 | atomic_set(&key->usage, 1); | |
1da177e4 | 286 | init_rwsem(&key->sem); |
7845bc39 | 287 | lockdep_set_class(&key->sem, &type->lock_class); |
1da177e4 LT |
288 | key->type = type; |
289 | key->user = user; | |
290 | key->quotalen = quotalen; | |
291 | key->datalen = type->def_datalen; | |
292 | key->uid = uid; | |
293 | key->gid = gid; | |
294 | key->perm = perm; | |
295 | key->flags = 0; | |
296 | key->expiry = 0; | |
297 | key->payload.data = NULL; | |
29db9190 | 298 | key->security = NULL; |
1da177e4 | 299 | |
7e047ef5 | 300 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) |
76d8aeab | 301 | key->flags |= 1 << KEY_FLAG_IN_QUOTA; |
1da177e4 LT |
302 | |
303 | memset(&key->type_data, 0, sizeof(key->type_data)); | |
304 | ||
305 | #ifdef KEY_DEBUGGING | |
306 | key->magic = KEY_DEBUG_MAGIC; | |
307 | #endif | |
308 | ||
29db9190 | 309 | /* let the security module know about the key */ |
d84f4f99 | 310 | ret = security_key_alloc(key, cred, flags); |
29db9190 DH |
311 | if (ret < 0) |
312 | goto security_error; | |
313 | ||
1da177e4 LT |
314 | /* publish the key by giving it a serial number */ |
315 | atomic_inc(&user->nkeys); | |
316 | key_alloc_serial(key); | |
317 | ||
29db9190 | 318 | error: |
1da177e4 LT |
319 | return key; |
320 | ||
29db9190 DH |
321 | security_error: |
322 | kfree(key->description); | |
1da177e4 | 323 | kmem_cache_free(key_jar, key); |
7e047ef5 | 324 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
1da177e4 LT |
325 | spin_lock(&user->lock); |
326 | user->qnkeys--; | |
327 | user->qnbytes -= quotalen; | |
328 | spin_unlock(&user->lock); | |
329 | } | |
330 | key_user_put(user); | |
29db9190 DH |
331 | key = ERR_PTR(ret); |
332 | goto error; | |
333 | ||
334 | no_memory_3: | |
335 | kmem_cache_free(key_jar, key); | |
336 | no_memory_2: | |
7e047ef5 | 337 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
29db9190 DH |
338 | spin_lock(&user->lock); |
339 | user->qnkeys--; | |
340 | user->qnbytes -= quotalen; | |
341 | spin_unlock(&user->lock); | |
342 | } | |
343 | key_user_put(user); | |
344 | no_memory_1: | |
1da177e4 LT |
345 | key = ERR_PTR(-ENOMEM); |
346 | goto error; | |
347 | ||
29db9190 | 348 | no_quota: |
1da177e4 LT |
349 | spin_unlock(&user->lock); |
350 | key_user_put(user); | |
351 | key = ERR_PTR(-EDQUOT); | |
352 | goto error; | |
a8b17ed0 | 353 | } |
1da177e4 LT |
354 | EXPORT_SYMBOL(key_alloc); |
355 | ||
973c9f4f DH |
356 | /** |
357 | * key_payload_reserve - Adjust data quota reservation for the key's payload | |
358 | * @key: The key to make the reservation for. | |
359 | * @datalen: The amount of data payload the caller now wants. | |
360 | * | |
361 | * Adjust the amount of the owning user's key data quota that a key reserves. | |
362 | * If the amount is increased, then -EDQUOT may be returned if there isn't | |
363 | * enough free quota available. | |
364 | * | |
365 | * If successful, 0 is returned. | |
1da177e4 LT |
366 | */ |
367 | int key_payload_reserve(struct key *key, size_t datalen) | |
368 | { | |
c5b60b5e | 369 | int delta = (int)datalen - key->datalen; |
1da177e4 LT |
370 | int ret = 0; |
371 | ||
372 | key_check(key); | |
373 | ||
374 | /* contemplate the quota adjustment */ | |
76d8aeab | 375 | if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { |
9a56c2db | 376 | unsigned maxbytes = uid_eq(key->user->uid, GLOBAL_ROOT_UID) ? |
0b77f5bf DH |
377 | key_quota_root_maxbytes : key_quota_maxbytes; |
378 | ||
1da177e4 LT |
379 | spin_lock(&key->user->lock); |
380 | ||
381 | if (delta > 0 && | |
0b77f5bf DH |
382 | (key->user->qnbytes + delta >= maxbytes || |
383 | key->user->qnbytes + delta < key->user->qnbytes)) { | |
1da177e4 LT |
384 | ret = -EDQUOT; |
385 | } | |
386 | else { | |
387 | key->user->qnbytes += delta; | |
388 | key->quotalen += delta; | |
389 | } | |
390 | spin_unlock(&key->user->lock); | |
391 | } | |
392 | ||
393 | /* change the recorded data length if that didn't generate an error */ | |
394 | if (ret == 0) | |
395 | key->datalen = datalen; | |
396 | ||
397 | return ret; | |
a8b17ed0 | 398 | } |
1da177e4 LT |
399 | EXPORT_SYMBOL(key_payload_reserve); |
400 | ||
1da177e4 | 401 | /* |
973c9f4f DH |
402 | * Instantiate a key and link it into the target keyring atomically. Must be |
403 | * called with the target keyring's semaphore writelocked. The target key's | |
404 | * semaphore need not be locked as instantiation is serialised by | |
405 | * key_construction_mutex. | |
1da177e4 LT |
406 | */ |
407 | static int __key_instantiate_and_link(struct key *key, | |
408 | const void *data, | |
409 | size_t datalen, | |
3e30148c | 410 | struct key *keyring, |
f70e2e06 | 411 | struct key *authkey, |
ceb73c12 | 412 | unsigned long *_prealloc) |
1da177e4 LT |
413 | { |
414 | int ret, awaken; | |
415 | ||
416 | key_check(key); | |
417 | key_check(keyring); | |
418 | ||
419 | awaken = 0; | |
420 | ret = -EBUSY; | |
421 | ||
76181c13 | 422 | mutex_lock(&key_construction_mutex); |
1da177e4 LT |
423 | |
424 | /* can't instantiate twice */ | |
76d8aeab | 425 | if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { |
1da177e4 LT |
426 | /* instantiate the key */ |
427 | ret = key->type->instantiate(key, data, datalen); | |
428 | ||
429 | if (ret == 0) { | |
430 | /* mark the key as being instantiated */ | |
1da177e4 | 431 | atomic_inc(&key->user->nikeys); |
76d8aeab | 432 | set_bit(KEY_FLAG_INSTANTIATED, &key->flags); |
1da177e4 | 433 | |
76d8aeab | 434 | if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) |
1da177e4 | 435 | awaken = 1; |
1da177e4 LT |
436 | |
437 | /* and link it into the destination keyring */ | |
438 | if (keyring) | |
f70e2e06 | 439 | __key_link(keyring, key, _prealloc); |
3e30148c DH |
440 | |
441 | /* disable the authorisation key */ | |
d84f4f99 DH |
442 | if (authkey) |
443 | key_revoke(authkey); | |
1da177e4 LT |
444 | } |
445 | } | |
446 | ||
76181c13 | 447 | mutex_unlock(&key_construction_mutex); |
1da177e4 LT |
448 | |
449 | /* wake up anyone waiting for a key to be constructed */ | |
450 | if (awaken) | |
76181c13 | 451 | wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT); |
1da177e4 LT |
452 | |
453 | return ret; | |
a8b17ed0 | 454 | } |
1da177e4 | 455 | |
973c9f4f DH |
456 | /** |
457 | * key_instantiate_and_link - Instantiate a key and link it into the keyring. | |
458 | * @key: The key to instantiate. | |
459 | * @data: The data to use to instantiate the keyring. | |
460 | * @datalen: The length of @data. | |
461 | * @keyring: Keyring to create a link in on success (or NULL). | |
462 | * @authkey: The authorisation token permitting instantiation. | |
463 | * | |
464 | * Instantiate a key that's in the uninstantiated state using the provided data | |
465 | * and, if successful, link it in to the destination keyring if one is | |
466 | * supplied. | |
467 | * | |
468 | * If successful, 0 is returned, the authorisation token is revoked and anyone | |
469 | * waiting for the key is woken up. If the key was already instantiated, | |
470 | * -EBUSY will be returned. | |
1da177e4 LT |
471 | */ |
472 | int key_instantiate_and_link(struct key *key, | |
473 | const void *data, | |
474 | size_t datalen, | |
3e30148c | 475 | struct key *keyring, |
d84f4f99 | 476 | struct key *authkey) |
1da177e4 | 477 | { |
ceb73c12 | 478 | unsigned long prealloc; |
1da177e4 LT |
479 | int ret; |
480 | ||
f70e2e06 DH |
481 | if (keyring) { |
482 | ret = __key_link_begin(keyring, key->type, key->description, | |
483 | &prealloc); | |
484 | if (ret < 0) | |
485 | return ret; | |
486 | } | |
1da177e4 | 487 | |
f70e2e06 DH |
488 | ret = __key_instantiate_and_link(key, data, datalen, keyring, authkey, |
489 | &prealloc); | |
1da177e4 LT |
490 | |
491 | if (keyring) | |
f70e2e06 | 492 | __key_link_end(keyring, key->type, prealloc); |
1da177e4 LT |
493 | |
494 | return ret; | |
a8b17ed0 | 495 | } |
1da177e4 LT |
496 | |
497 | EXPORT_SYMBOL(key_instantiate_and_link); | |
498 | ||
973c9f4f | 499 | /** |
fdd1b945 | 500 | * key_reject_and_link - Negatively instantiate a key and link it into the keyring. |
973c9f4f DH |
501 | * @key: The key to instantiate. |
502 | * @timeout: The timeout on the negative key. | |
fdd1b945 | 503 | * @error: The error to return when the key is hit. |
973c9f4f DH |
504 | * @keyring: Keyring to create a link in on success (or NULL). |
505 | * @authkey: The authorisation token permitting instantiation. | |
506 | * | |
507 | * Negatively instantiate a key that's in the uninstantiated state and, if | |
fdd1b945 DH |
508 | * successful, set its timeout and stored error and link it in to the |
509 | * destination keyring if one is supplied. The key and any links to the key | |
510 | * will be automatically garbage collected after the timeout expires. | |
973c9f4f DH |
511 | * |
512 | * Negative keys are used to rate limit repeated request_key() calls by causing | |
fdd1b945 DH |
513 | * them to return the stored error code (typically ENOKEY) until the negative |
514 | * key expires. | |
973c9f4f DH |
515 | * |
516 | * If successful, 0 is returned, the authorisation token is revoked and anyone | |
517 | * waiting for the key is woken up. If the key was already instantiated, | |
518 | * -EBUSY will be returned. | |
1da177e4 | 519 | */ |
fdd1b945 | 520 | int key_reject_and_link(struct key *key, |
1da177e4 | 521 | unsigned timeout, |
fdd1b945 | 522 | unsigned error, |
3e30148c | 523 | struct key *keyring, |
d84f4f99 | 524 | struct key *authkey) |
1da177e4 | 525 | { |
ceb73c12 | 526 | unsigned long prealloc; |
1da177e4 | 527 | struct timespec now; |
f70e2e06 | 528 | int ret, awaken, link_ret = 0; |
1da177e4 LT |
529 | |
530 | key_check(key); | |
531 | key_check(keyring); | |
532 | ||
533 | awaken = 0; | |
534 | ret = -EBUSY; | |
535 | ||
536 | if (keyring) | |
f70e2e06 DH |
537 | link_ret = __key_link_begin(keyring, key->type, |
538 | key->description, &prealloc); | |
1da177e4 | 539 | |
76181c13 | 540 | mutex_lock(&key_construction_mutex); |
1da177e4 LT |
541 | |
542 | /* can't instantiate twice */ | |
76d8aeab | 543 | if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { |
1da177e4 | 544 | /* mark the key as being negatively instantiated */ |
1da177e4 | 545 | atomic_inc(&key->user->nikeys); |
76d8aeab DH |
546 | set_bit(KEY_FLAG_NEGATIVE, &key->flags); |
547 | set_bit(KEY_FLAG_INSTANTIATED, &key->flags); | |
fdd1b945 | 548 | key->type_data.reject_error = -error; |
1da177e4 LT |
549 | now = current_kernel_time(); |
550 | key->expiry = now.tv_sec + timeout; | |
c08ef808 | 551 | key_schedule_gc(key->expiry + key_gc_delay); |
1da177e4 | 552 | |
76d8aeab | 553 | if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) |
1da177e4 | 554 | awaken = 1; |
1da177e4 | 555 | |
1da177e4 LT |
556 | ret = 0; |
557 | ||
558 | /* and link it into the destination keyring */ | |
f70e2e06 DH |
559 | if (keyring && link_ret == 0) |
560 | __key_link(keyring, key, &prealloc); | |
3e30148c DH |
561 | |
562 | /* disable the authorisation key */ | |
d84f4f99 DH |
563 | if (authkey) |
564 | key_revoke(authkey); | |
1da177e4 LT |
565 | } |
566 | ||
76181c13 | 567 | mutex_unlock(&key_construction_mutex); |
1da177e4 LT |
568 | |
569 | if (keyring) | |
f70e2e06 | 570 | __key_link_end(keyring, key->type, prealloc); |
1da177e4 LT |
571 | |
572 | /* wake up anyone waiting for a key to be constructed */ | |
573 | if (awaken) | |
76181c13 | 574 | wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT); |
1da177e4 | 575 | |
f70e2e06 | 576 | return ret == 0 ? link_ret : ret; |
a8b17ed0 | 577 | } |
fdd1b945 | 578 | EXPORT_SYMBOL(key_reject_and_link); |
1da177e4 | 579 | |
973c9f4f DH |
580 | /** |
581 | * key_put - Discard a reference to a key. | |
582 | * @key: The key to discard a reference from. | |
583 | * | |
584 | * Discard a reference to a key, and when all the references are gone, we | |
585 | * schedule the cleanup task to come and pull it out of the tree in process | |
586 | * context at some later time. | |
1da177e4 LT |
587 | */ |
588 | void key_put(struct key *key) | |
589 | { | |
590 | if (key) { | |
591 | key_check(key); | |
592 | ||
593 | if (atomic_dec_and_test(&key->usage)) | |
3b07e9ca | 594 | schedule_work(&key_gc_work); |
1da177e4 | 595 | } |
a8b17ed0 | 596 | } |
1da177e4 LT |
597 | EXPORT_SYMBOL(key_put); |
598 | ||
1da177e4 | 599 | /* |
973c9f4f | 600 | * Find a key by its serial number. |
1da177e4 LT |
601 | */ |
602 | struct key *key_lookup(key_serial_t id) | |
603 | { | |
604 | struct rb_node *n; | |
605 | struct key *key; | |
606 | ||
607 | spin_lock(&key_serial_lock); | |
608 | ||
609 | /* search the tree for the specified key */ | |
610 | n = key_serial_tree.rb_node; | |
611 | while (n) { | |
612 | key = rb_entry(n, struct key, serial_node); | |
613 | ||
614 | if (id < key->serial) | |
615 | n = n->rb_left; | |
616 | else if (id > key->serial) | |
617 | n = n->rb_right; | |
618 | else | |
619 | goto found; | |
620 | } | |
621 | ||
973c9f4f | 622 | not_found: |
1da177e4 LT |
623 | key = ERR_PTR(-ENOKEY); |
624 | goto error; | |
625 | ||
973c9f4f | 626 | found: |
5593122e DH |
627 | /* pretend it doesn't exist if it is awaiting deletion */ |
628 | if (atomic_read(&key->usage) == 0) | |
1da177e4 LT |
629 | goto not_found; |
630 | ||
631 | /* this races with key_put(), but that doesn't matter since key_put() | |
632 | * doesn't actually change the key | |
633 | */ | |
634 | atomic_inc(&key->usage); | |
635 | ||
973c9f4f | 636 | error: |
1da177e4 LT |
637 | spin_unlock(&key_serial_lock); |
638 | return key; | |
a8b17ed0 | 639 | } |
1da177e4 | 640 | |
1da177e4 | 641 | /* |
973c9f4f DH |
642 | * Find and lock the specified key type against removal. |
643 | * | |
644 | * We return with the sem read-locked if successful. If the type wasn't | |
645 | * available -ENOKEY is returned instead. | |
1da177e4 LT |
646 | */ |
647 | struct key_type *key_type_lookup(const char *type) | |
648 | { | |
649 | struct key_type *ktype; | |
650 | ||
651 | down_read(&key_types_sem); | |
652 | ||
653 | /* look up the key type to see if it's one of the registered kernel | |
654 | * types */ | |
655 | list_for_each_entry(ktype, &key_types_list, link) { | |
656 | if (strcmp(ktype->name, type) == 0) | |
657 | goto found_kernel_type; | |
658 | } | |
659 | ||
660 | up_read(&key_types_sem); | |
661 | ktype = ERR_PTR(-ENOKEY); | |
662 | ||
973c9f4f | 663 | found_kernel_type: |
1da177e4 | 664 | return ktype; |
a8b17ed0 | 665 | } |
1da177e4 | 666 | |
59e6b9c1 BS |
667 | void key_set_timeout(struct key *key, unsigned timeout) |
668 | { | |
669 | struct timespec now; | |
670 | time_t expiry = 0; | |
671 | ||
672 | /* make the changes with the locks held to prevent races */ | |
673 | down_write(&key->sem); | |
674 | ||
675 | if (timeout > 0) { | |
676 | now = current_kernel_time(); | |
677 | expiry = now.tv_sec + timeout; | |
678 | } | |
679 | ||
680 | key->expiry = expiry; | |
681 | key_schedule_gc(key->expiry + key_gc_delay); | |
682 | ||
683 | up_write(&key->sem); | |
684 | } | |
685 | EXPORT_SYMBOL_GPL(key_set_timeout); | |
686 | ||
1da177e4 | 687 | /* |
973c9f4f | 688 | * Unlock a key type locked by key_type_lookup(). |
1da177e4 LT |
689 | */ |
690 | void key_type_put(struct key_type *ktype) | |
691 | { | |
692 | up_read(&key_types_sem); | |
a8b17ed0 | 693 | } |
1da177e4 | 694 | |
1da177e4 | 695 | /* |
973c9f4f DH |
696 | * Attempt to update an existing key. |
697 | * | |
698 | * The key is given to us with an incremented refcount that we need to discard | |
699 | * if we get an error. | |
1da177e4 | 700 | */ |
664cceb0 DH |
701 | static inline key_ref_t __key_update(key_ref_t key_ref, |
702 | const void *payload, size_t plen) | |
1da177e4 | 703 | { |
664cceb0 | 704 | struct key *key = key_ref_to_ptr(key_ref); |
1da177e4 LT |
705 | int ret; |
706 | ||
707 | /* need write permission on the key to update it */ | |
29db9190 DH |
708 | ret = key_permission(key_ref, KEY_WRITE); |
709 | if (ret < 0) | |
1da177e4 LT |
710 | goto error; |
711 | ||
712 | ret = -EEXIST; | |
713 | if (!key->type->update) | |
714 | goto error; | |
715 | ||
716 | down_write(&key->sem); | |
717 | ||
718 | ret = key->type->update(key, payload, plen); | |
76d8aeab | 719 | if (ret == 0) |
1da177e4 | 720 | /* updating a negative key instantiates it */ |
76d8aeab | 721 | clear_bit(KEY_FLAG_NEGATIVE, &key->flags); |
1da177e4 LT |
722 | |
723 | up_write(&key->sem); | |
724 | ||
725 | if (ret < 0) | |
726 | goto error; | |
664cceb0 DH |
727 | out: |
728 | return key_ref; | |
1da177e4 | 729 | |
664cceb0 | 730 | error: |
1da177e4 | 731 | key_put(key); |
664cceb0 | 732 | key_ref = ERR_PTR(ret); |
1da177e4 | 733 | goto out; |
a8b17ed0 | 734 | } |
1da177e4 | 735 | |
973c9f4f DH |
736 | /** |
737 | * key_create_or_update - Update or create and instantiate a key. | |
738 | * @keyring_ref: A pointer to the destination keyring with possession flag. | |
739 | * @type: The type of key. | |
740 | * @description: The searchable description for the key. | |
741 | * @payload: The data to use to instantiate or update the key. | |
742 | * @plen: The length of @payload. | |
743 | * @perm: The permissions mask for a new key. | |
744 | * @flags: The quota flags for a new key. | |
745 | * | |
746 | * Search the destination keyring for a key of the same description and if one | |
747 | * is found, update it, otherwise create and instantiate a new one and create a | |
748 | * link to it from that keyring. | |
749 | * | |
750 | * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be | |
751 | * concocted. | |
752 | * | |
753 | * Returns a pointer to the new key if successful, -ENODEV if the key type | |
754 | * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the | |
755 | * caller isn't permitted to modify the keyring or the LSM did not permit | |
756 | * creation of the key. | |
757 | * | |
758 | * On success, the possession flag from the keyring ref will be tacked on to | |
759 | * the key ref before it is returned. | |
1da177e4 | 760 | */ |
664cceb0 DH |
761 | key_ref_t key_create_or_update(key_ref_t keyring_ref, |
762 | const char *type, | |
763 | const char *description, | |
764 | const void *payload, | |
765 | size_t plen, | |
6b79ccb5 | 766 | key_perm_t perm, |
7e047ef5 | 767 | unsigned long flags) |
1da177e4 | 768 | { |
ceb73c12 | 769 | unsigned long prealloc; |
d84f4f99 | 770 | const struct cred *cred = current_cred(); |
1da177e4 | 771 | struct key_type *ktype; |
664cceb0 | 772 | struct key *keyring, *key = NULL; |
664cceb0 | 773 | key_ref_t key_ref; |
1da177e4 LT |
774 | int ret; |
775 | ||
1da177e4 LT |
776 | /* look up the key type to see if it's one of the registered kernel |
777 | * types */ | |
778 | ktype = key_type_lookup(type); | |
779 | if (IS_ERR(ktype)) { | |
664cceb0 | 780 | key_ref = ERR_PTR(-ENODEV); |
1da177e4 LT |
781 | goto error; |
782 | } | |
783 | ||
664cceb0 | 784 | key_ref = ERR_PTR(-EINVAL); |
1da177e4 LT |
785 | if (!ktype->match || !ktype->instantiate) |
786 | goto error_2; | |
787 | ||
664cceb0 DH |
788 | keyring = key_ref_to_ptr(keyring_ref); |
789 | ||
790 | key_check(keyring); | |
791 | ||
c3a9d654 DH |
792 | key_ref = ERR_PTR(-ENOTDIR); |
793 | if (keyring->type != &key_type_keyring) | |
794 | goto error_2; | |
795 | ||
f70e2e06 DH |
796 | ret = __key_link_begin(keyring, ktype, description, &prealloc); |
797 | if (ret < 0) | |
798 | goto error_2; | |
664cceb0 DH |
799 | |
800 | /* if we're going to allocate a new key, we're going to have | |
801 | * to modify the keyring */ | |
29db9190 DH |
802 | ret = key_permission(keyring_ref, KEY_WRITE); |
803 | if (ret < 0) { | |
804 | key_ref = ERR_PTR(ret); | |
664cceb0 | 805 | goto error_3; |
29db9190 | 806 | } |
664cceb0 | 807 | |
1d9b7d97 DH |
808 | /* if it's possible to update this type of key, search for an existing |
809 | * key of the same type and description in the destination keyring and | |
810 | * update that instead if possible | |
1da177e4 | 811 | */ |
1d9b7d97 DH |
812 | if (ktype->update) { |
813 | key_ref = __keyring_search_one(keyring_ref, ktype, description, | |
814 | 0); | |
815 | if (!IS_ERR(key_ref)) | |
816 | goto found_matching_key; | |
817 | } | |
1da177e4 | 818 | |
6b79ccb5 AR |
819 | /* if the client doesn't provide, decide on the permissions we want */ |
820 | if (perm == KEY_PERM_UNDEF) { | |
821 | perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR; | |
822 | perm |= KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK | KEY_USR_SETATTR; | |
1da177e4 | 823 | |
6b79ccb5 AR |
824 | if (ktype->read) |
825 | perm |= KEY_POS_READ | KEY_USR_READ; | |
1da177e4 | 826 | |
6b79ccb5 AR |
827 | if (ktype == &key_type_keyring || ktype->update) |
828 | perm |= KEY_USR_WRITE; | |
829 | } | |
1da177e4 LT |
830 | |
831 | /* allocate a new key */ | |
d84f4f99 DH |
832 | key = key_alloc(ktype, description, cred->fsuid, cred->fsgid, cred, |
833 | perm, flags); | |
1da177e4 | 834 | if (IS_ERR(key)) { |
e231c2ee | 835 | key_ref = ERR_CAST(key); |
1da177e4 LT |
836 | goto error_3; |
837 | } | |
838 | ||
839 | /* instantiate it and link it into the target keyring */ | |
f70e2e06 DH |
840 | ret = __key_instantiate_and_link(key, payload, plen, keyring, NULL, |
841 | &prealloc); | |
1da177e4 LT |
842 | if (ret < 0) { |
843 | key_put(key); | |
664cceb0 DH |
844 | key_ref = ERR_PTR(ret); |
845 | goto error_3; | |
1da177e4 LT |
846 | } |
847 | ||
664cceb0 DH |
848 | key_ref = make_key_ref(key, is_key_possessed(keyring_ref)); |
849 | ||
1da177e4 | 850 | error_3: |
f70e2e06 | 851 | __key_link_end(keyring, ktype, prealloc); |
1da177e4 LT |
852 | error_2: |
853 | key_type_put(ktype); | |
854 | error: | |
664cceb0 | 855 | return key_ref; |
1da177e4 LT |
856 | |
857 | found_matching_key: | |
858 | /* we found a matching key, so we're going to try to update it | |
859 | * - we can drop the locks first as we have the key pinned | |
860 | */ | |
f70e2e06 | 861 | __key_link_end(keyring, ktype, prealloc); |
1da177e4 LT |
862 | key_type_put(ktype); |
863 | ||
664cceb0 | 864 | key_ref = __key_update(key_ref, payload, plen); |
1da177e4 | 865 | goto error; |
a8b17ed0 | 866 | } |
1da177e4 LT |
867 | EXPORT_SYMBOL(key_create_or_update); |
868 | ||
973c9f4f DH |
869 | /** |
870 | * key_update - Update a key's contents. | |
871 | * @key_ref: The pointer (plus possession flag) to the key. | |
872 | * @payload: The data to be used to update the key. | |
873 | * @plen: The length of @payload. | |
874 | * | |
875 | * Attempt to update the contents of a key with the given payload data. The | |
876 | * caller must be granted Write permission on the key. Negative keys can be | |
877 | * instantiated by this method. | |
878 | * | |
879 | * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key | |
880 | * type does not support updating. The key type may return other errors. | |
1da177e4 | 881 | */ |
664cceb0 | 882 | int key_update(key_ref_t key_ref, const void *payload, size_t plen) |
1da177e4 | 883 | { |
664cceb0 | 884 | struct key *key = key_ref_to_ptr(key_ref); |
1da177e4 LT |
885 | int ret; |
886 | ||
887 | key_check(key); | |
888 | ||
889 | /* the key must be writable */ | |
29db9190 DH |
890 | ret = key_permission(key_ref, KEY_WRITE); |
891 | if (ret < 0) | |
1da177e4 LT |
892 | goto error; |
893 | ||
894 | /* attempt to update it if supported */ | |
895 | ret = -EOPNOTSUPP; | |
896 | if (key->type->update) { | |
897 | down_write(&key->sem); | |
1da177e4 | 898 | |
29db9190 | 899 | ret = key->type->update(key, payload, plen); |
76d8aeab | 900 | if (ret == 0) |
1da177e4 | 901 | /* updating a negative key instantiates it */ |
76d8aeab | 902 | clear_bit(KEY_FLAG_NEGATIVE, &key->flags); |
1da177e4 LT |
903 | |
904 | up_write(&key->sem); | |
905 | } | |
906 | ||
907 | error: | |
908 | return ret; | |
a8b17ed0 | 909 | } |
1da177e4 LT |
910 | EXPORT_SYMBOL(key_update); |
911 | ||
973c9f4f DH |
912 | /** |
913 | * key_revoke - Revoke a key. | |
914 | * @key: The key to be revoked. | |
915 | * | |
916 | * Mark a key as being revoked and ask the type to free up its resources. The | |
917 | * revocation timeout is set and the key and all its links will be | |
918 | * automatically garbage collected after key_gc_delay amount of time if they | |
919 | * are not manually dealt with first. | |
1da177e4 LT |
920 | */ |
921 | void key_revoke(struct key *key) | |
922 | { | |
5d135440 DH |
923 | struct timespec now; |
924 | time_t time; | |
925 | ||
1da177e4 LT |
926 | key_check(key); |
927 | ||
76181c13 DH |
928 | /* make sure no one's trying to change or use the key when we mark it |
929 | * - we tell lockdep that we might nest because we might be revoking an | |
930 | * authorisation key whilst holding the sem on a key we've just | |
931 | * instantiated | |
932 | */ | |
933 | down_write_nested(&key->sem, 1); | |
934 | if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags) && | |
935 | key->type->revoke) | |
04c567d9 DH |
936 | key->type->revoke(key); |
937 | ||
5d135440 DH |
938 | /* set the death time to no more than the expiry time */ |
939 | now = current_kernel_time(); | |
940 | time = now.tv_sec; | |
941 | if (key->revoked_at == 0 || key->revoked_at > time) { | |
942 | key->revoked_at = time; | |
c08ef808 | 943 | key_schedule_gc(key->revoked_at + key_gc_delay); |
5d135440 DH |
944 | } |
945 | ||
1da177e4 | 946 | up_write(&key->sem); |
a8b17ed0 | 947 | } |
1da177e4 LT |
948 | EXPORT_SYMBOL(key_revoke); |
949 | ||
fd75815f DH |
950 | /** |
951 | * key_invalidate - Invalidate a key. | |
952 | * @key: The key to be invalidated. | |
953 | * | |
954 | * Mark a key as being invalidated and have it cleaned up immediately. The key | |
955 | * is ignored by all searches and other operations from this point. | |
956 | */ | |
957 | void key_invalidate(struct key *key) | |
958 | { | |
959 | kenter("%d", key_serial(key)); | |
960 | ||
961 | key_check(key); | |
962 | ||
963 | if (!test_bit(KEY_FLAG_INVALIDATED, &key->flags)) { | |
964 | down_write_nested(&key->sem, 1); | |
965 | if (!test_and_set_bit(KEY_FLAG_INVALIDATED, &key->flags)) | |
966 | key_schedule_gc_links(); | |
967 | up_write(&key->sem); | |
968 | } | |
969 | } | |
970 | EXPORT_SYMBOL(key_invalidate); | |
971 | ||
973c9f4f DH |
972 | /** |
973 | * register_key_type - Register a type of key. | |
974 | * @ktype: The new key type. | |
975 | * | |
976 | * Register a new key type. | |
977 | * | |
978 | * Returns 0 on success or -EEXIST if a type of this name already exists. | |
1da177e4 LT |
979 | */ |
980 | int register_key_type(struct key_type *ktype) | |
981 | { | |
982 | struct key_type *p; | |
983 | int ret; | |
984 | ||
7845bc39 DH |
985 | memset(&ktype->lock_class, 0, sizeof(ktype->lock_class)); |
986 | ||
1da177e4 LT |
987 | ret = -EEXIST; |
988 | down_write(&key_types_sem); | |
989 | ||
990 | /* disallow key types with the same name */ | |
991 | list_for_each_entry(p, &key_types_list, link) { | |
992 | if (strcmp(p->name, ktype->name) == 0) | |
993 | goto out; | |
994 | } | |
995 | ||
996 | /* store the type */ | |
997 | list_add(&ktype->link, &key_types_list); | |
1eb1bcf5 DH |
998 | |
999 | pr_notice("Key type %s registered\n", ktype->name); | |
1da177e4 LT |
1000 | ret = 0; |
1001 | ||
973c9f4f | 1002 | out: |
1da177e4 LT |
1003 | up_write(&key_types_sem); |
1004 | return ret; | |
a8b17ed0 | 1005 | } |
1da177e4 LT |
1006 | EXPORT_SYMBOL(register_key_type); |
1007 | ||
973c9f4f DH |
1008 | /** |
1009 | * unregister_key_type - Unregister a type of key. | |
1010 | * @ktype: The key type. | |
1011 | * | |
1012 | * Unregister a key type and mark all the extant keys of this type as dead. | |
1013 | * Those keys of this type are then destroyed to get rid of their payloads and | |
1014 | * they and their links will be garbage collected as soon as possible. | |
1da177e4 LT |
1015 | */ |
1016 | void unregister_key_type(struct key_type *ktype) | |
1017 | { | |
1da177e4 | 1018 | down_write(&key_types_sem); |
1da177e4 | 1019 | list_del_init(&ktype->link); |
0c061b57 DH |
1020 | downgrade_write(&key_types_sem); |
1021 | key_gc_keytype(ktype); | |
1eb1bcf5 | 1022 | pr_notice("Key type %s unregistered\n", ktype->name); |
0c061b57 | 1023 | up_read(&key_types_sem); |
a8b17ed0 | 1024 | } |
1da177e4 LT |
1025 | EXPORT_SYMBOL(unregister_key_type); |
1026 | ||
1da177e4 | 1027 | /* |
973c9f4f | 1028 | * Initialise the key management state. |
1da177e4 LT |
1029 | */ |
1030 | void __init key_init(void) | |
1031 | { | |
1032 | /* allocate a slab in which we can store keys */ | |
1033 | key_jar = kmem_cache_create("key_jar", sizeof(struct key), | |
20c2df83 | 1034 | 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1da177e4 LT |
1035 | |
1036 | /* add the special key types */ | |
1037 | list_add_tail(&key_type_keyring.link, &key_types_list); | |
1038 | list_add_tail(&key_type_dead.link, &key_types_list); | |
1039 | list_add_tail(&key_type_user.link, &key_types_list); | |
9f6ed2ca | 1040 | list_add_tail(&key_type_logon.link, &key_types_list); |
1da177e4 LT |
1041 | |
1042 | /* record the root user tracking */ | |
1043 | rb_link_node(&root_key_user.node, | |
1044 | NULL, | |
1045 | &key_user_tree.rb_node); | |
1046 | ||
1047 | rb_insert_color(&root_key_user.node, | |
1048 | &key_user_tree); | |
a8b17ed0 | 1049 | } |