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 | ||
8bc16dea | 24 | 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 | ||
973c9f4f | 39 | /* We serialise key instantiation and link */ |
76181c13 | 40 | DEFINE_MUTEX(key_construction_mutex); |
1da177e4 | 41 | |
973c9f4f | 42 | /* Any key who's type gets unegistered will be re-typed to this */ |
1ae8f407 | 43 | static struct key_type key_type_dead = { |
1da177e4 LT |
44 | .name = "dead", |
45 | }; | |
46 | ||
47 | #ifdef KEY_DEBUGGING | |
48 | void __key_check(const struct key *key) | |
49 | { | |
50 | printk("__key_check: key %p {%08x} should be {%08x}\n", | |
51 | key, key->magic, KEY_DEBUG_MAGIC); | |
52 | BUG(); | |
53 | } | |
54 | #endif | |
55 | ||
1da177e4 | 56 | /* |
973c9f4f DH |
57 | * Get the key quota record for a user, allocating a new record if one doesn't |
58 | * already exist. | |
1da177e4 | 59 | */ |
1d1e9756 | 60 | struct key_user *key_user_lookup(uid_t uid, struct user_namespace *user_ns) |
1da177e4 LT |
61 | { |
62 | struct key_user *candidate = NULL, *user; | |
63 | struct rb_node *parent = NULL; | |
64 | struct rb_node **p; | |
65 | ||
973c9f4f | 66 | try_again: |
1da177e4 LT |
67 | p = &key_user_tree.rb_node; |
68 | spin_lock(&key_user_lock); | |
69 | ||
70 | /* search the tree for a user record with a matching UID */ | |
71 | while (*p) { | |
72 | parent = *p; | |
73 | user = rb_entry(parent, struct key_user, node); | |
74 | ||
75 | if (uid < user->uid) | |
76 | p = &(*p)->rb_left; | |
77 | else if (uid > user->uid) | |
78 | p = &(*p)->rb_right; | |
1d1e9756 SH |
79 | else if (user_ns < user->user_ns) |
80 | p = &(*p)->rb_left; | |
81 | else if (user_ns > user->user_ns) | |
82 | p = &(*p)->rb_right; | |
1da177e4 LT |
83 | else |
84 | goto found; | |
85 | } | |
86 | ||
87 | /* if we get here, we failed to find a match in the tree */ | |
88 | if (!candidate) { | |
89 | /* allocate a candidate user record if we don't already have | |
90 | * one */ | |
91 | spin_unlock(&key_user_lock); | |
92 | ||
93 | user = NULL; | |
94 | candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL); | |
95 | if (unlikely(!candidate)) | |
96 | goto out; | |
97 | ||
98 | /* the allocation may have scheduled, so we need to repeat the | |
99 | * search lest someone else added the record whilst we were | |
100 | * asleep */ | |
101 | goto try_again; | |
102 | } | |
103 | ||
104 | /* if we get here, then the user record still hadn't appeared on the | |
105 | * second pass - so we use the candidate record */ | |
106 | atomic_set(&candidate->usage, 1); | |
107 | atomic_set(&candidate->nkeys, 0); | |
108 | atomic_set(&candidate->nikeys, 0); | |
109 | candidate->uid = uid; | |
1d1e9756 | 110 | candidate->user_ns = get_user_ns(user_ns); |
1da177e4 LT |
111 | candidate->qnkeys = 0; |
112 | candidate->qnbytes = 0; | |
113 | spin_lock_init(&candidate->lock); | |
76181c13 | 114 | mutex_init(&candidate->cons_lock); |
1da177e4 LT |
115 | |
116 | rb_link_node(&candidate->node, parent, p); | |
117 | rb_insert_color(&candidate->node, &key_user_tree); | |
118 | spin_unlock(&key_user_lock); | |
119 | user = candidate; | |
120 | goto out; | |
121 | ||
122 | /* okay - we found a user record for this UID */ | |
973c9f4f | 123 | found: |
1da177e4 LT |
124 | atomic_inc(&user->usage); |
125 | spin_unlock(&key_user_lock); | |
a7f988ba | 126 | kfree(candidate); |
973c9f4f | 127 | out: |
1da177e4 | 128 | return user; |
a8b17ed0 | 129 | } |
1da177e4 | 130 | |
1da177e4 | 131 | /* |
973c9f4f | 132 | * Dispose of a user structure |
1da177e4 LT |
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); | |
1d1e9756 | 139 | put_user_ns(user->user_ns); |
1da177e4 LT |
140 | |
141 | kfree(user); | |
142 | } | |
a8b17ed0 | 143 | } |
1da177e4 | 144 | |
1da177e4 | 145 | /* |
973c9f4f DH |
146 | * Allocate a serial number for a key. These are assigned randomly to avoid |
147 | * security issues through covert channel problems. | |
1da177e4 LT |
148 | */ |
149 | static inline void key_alloc_serial(struct key *key) | |
150 | { | |
151 | struct rb_node *parent, **p; | |
152 | struct key *xkey; | |
153 | ||
e51f6d34 | 154 | /* propose a random serial number and look for a hole for it in the |
1da177e4 | 155 | * serial number tree */ |
e51f6d34 ML |
156 | do { |
157 | get_random_bytes(&key->serial, sizeof(key->serial)); | |
158 | ||
159 | key->serial >>= 1; /* negative numbers are not permitted */ | |
160 | } while (key->serial < 3); | |
161 | ||
162 | spin_lock(&key_serial_lock); | |
1da177e4 | 163 | |
9ad0830f | 164 | attempt_insertion: |
1da177e4 LT |
165 | parent = NULL; |
166 | p = &key_serial_tree.rb_node; | |
167 | ||
168 | while (*p) { | |
169 | parent = *p; | |
170 | xkey = rb_entry(parent, struct key, serial_node); | |
171 | ||
172 | if (key->serial < xkey->serial) | |
173 | p = &(*p)->rb_left; | |
174 | else if (key->serial > xkey->serial) | |
175 | p = &(*p)->rb_right; | |
176 | else | |
177 | goto serial_exists; | |
178 | } | |
9ad0830f DH |
179 | |
180 | /* we've found a suitable hole - arrange for this key to occupy it */ | |
181 | rb_link_node(&key->serial_node, parent, p); | |
182 | rb_insert_color(&key->serial_node, &key_serial_tree); | |
183 | ||
184 | spin_unlock(&key_serial_lock); | |
185 | return; | |
1da177e4 LT |
186 | |
187 | /* we found a key with the proposed serial number - walk the tree from | |
188 | * that point looking for the next unused serial number */ | |
e51f6d34 | 189 | serial_exists: |
1da177e4 | 190 | for (;;) { |
e51f6d34 | 191 | key->serial++; |
9ad0830f DH |
192 | if (key->serial < 3) { |
193 | key->serial = 3; | |
194 | goto attempt_insertion; | |
195 | } | |
1da177e4 LT |
196 | |
197 | parent = rb_next(parent); | |
198 | if (!parent) | |
9ad0830f | 199 | goto attempt_insertion; |
1da177e4 LT |
200 | |
201 | xkey = rb_entry(parent, struct key, serial_node); | |
202 | if (key->serial < xkey->serial) | |
9ad0830f | 203 | goto attempt_insertion; |
1da177e4 | 204 | } |
a8b17ed0 | 205 | } |
1da177e4 | 206 | |
973c9f4f DH |
207 | /** |
208 | * key_alloc - Allocate a key of the specified type. | |
209 | * @type: The type of key to allocate. | |
210 | * @desc: The key description to allow the key to be searched out. | |
211 | * @uid: The owner of the new key. | |
212 | * @gid: The group ID for the new key's group permissions. | |
213 | * @cred: The credentials specifying UID namespace. | |
214 | * @perm: The permissions mask of the new key. | |
215 | * @flags: Flags specifying quota properties. | |
216 | * | |
217 | * Allocate a key of the specified type with the attributes given. The key is | |
218 | * returned in an uninstantiated state and the caller needs to instantiate the | |
219 | * key before returning. | |
220 | * | |
221 | * The user's key count quota is updated to reflect the creation of the key and | |
222 | * the user's key data quota has the default for the key type reserved. The | |
223 | * instantiation function should amend this as necessary. If insufficient | |
224 | * quota is available, -EDQUOT will be returned. | |
225 | * | |
226 | * The LSM security modules can prevent a key being created, in which case | |
227 | * -EACCES will be returned. | |
228 | * | |
229 | * Returns a pointer to the new key if successful and an error code otherwise. | |
230 | * | |
231 | * Note that the caller needs to ensure the key type isn't uninstantiated. | |
232 | * Internally this can be done by locking key_types_sem. Externally, this can | |
233 | * be done by either never unregistering the key type, or making sure | |
234 | * key_alloc() calls don't race with module unloading. | |
1da177e4 LT |
235 | */ |
236 | struct key *key_alloc(struct key_type *type, const char *desc, | |
d84f4f99 | 237 | uid_t uid, gid_t gid, const struct cred *cred, |
7e047ef5 | 238 | key_perm_t perm, unsigned long flags) |
1da177e4 LT |
239 | { |
240 | struct key_user *user = NULL; | |
241 | struct key *key; | |
242 | size_t desclen, quotalen; | |
29db9190 | 243 | int ret; |
1da177e4 LT |
244 | |
245 | key = ERR_PTR(-EINVAL); | |
246 | if (!desc || !*desc) | |
247 | goto error; | |
248 | ||
b9fffa38 DH |
249 | if (type->vet_description) { |
250 | ret = type->vet_description(desc); | |
251 | if (ret < 0) { | |
252 | key = ERR_PTR(ret); | |
253 | goto error; | |
254 | } | |
255 | } | |
256 | ||
1da177e4 LT |
257 | desclen = strlen(desc) + 1; |
258 | quotalen = desclen + type->def_datalen; | |
259 | ||
260 | /* get hold of the key tracking for this user */ | |
1d1e9756 | 261 | user = key_user_lookup(uid, cred->user->user_ns); |
1da177e4 LT |
262 | if (!user) |
263 | goto no_memory_1; | |
264 | ||
265 | /* check that the user's quota permits allocation of another key and | |
266 | * its description */ | |
7e047ef5 | 267 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
0b77f5bf DH |
268 | unsigned maxkeys = (uid == 0) ? |
269 | key_quota_root_maxkeys : key_quota_maxkeys; | |
270 | unsigned maxbytes = (uid == 0) ? | |
271 | key_quota_root_maxbytes : key_quota_maxbytes; | |
272 | ||
1da177e4 | 273 | spin_lock(&user->lock); |
7e047ef5 | 274 | if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) { |
0b77f5bf DH |
275 | if (user->qnkeys + 1 >= maxkeys || |
276 | user->qnbytes + quotalen >= maxbytes || | |
277 | user->qnbytes + quotalen < user->qnbytes) | |
7e047ef5 DH |
278 | goto no_quota; |
279 | } | |
1da177e4 LT |
280 | |
281 | user->qnkeys++; | |
282 | user->qnbytes += quotalen; | |
283 | spin_unlock(&user->lock); | |
284 | } | |
285 | ||
286 | /* allocate and initialise the key and its description */ | |
e94b1766 | 287 | key = kmem_cache_alloc(key_jar, GFP_KERNEL); |
1da177e4 LT |
288 | if (!key) |
289 | goto no_memory_2; | |
290 | ||
291 | if (desc) { | |
48ad504e | 292 | key->description = kmemdup(desc, desclen, GFP_KERNEL); |
1da177e4 LT |
293 | if (!key->description) |
294 | goto no_memory_3; | |
1da177e4 LT |
295 | } |
296 | ||
297 | atomic_set(&key->usage, 1); | |
1da177e4 LT |
298 | init_rwsem(&key->sem); |
299 | key->type = type; | |
300 | key->user = user; | |
301 | key->quotalen = quotalen; | |
302 | key->datalen = type->def_datalen; | |
303 | key->uid = uid; | |
304 | key->gid = gid; | |
305 | key->perm = perm; | |
306 | key->flags = 0; | |
307 | key->expiry = 0; | |
308 | key->payload.data = NULL; | |
29db9190 | 309 | key->security = NULL; |
1da177e4 | 310 | |
7e047ef5 | 311 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) |
76d8aeab | 312 | key->flags |= 1 << KEY_FLAG_IN_QUOTA; |
1da177e4 LT |
313 | |
314 | memset(&key->type_data, 0, sizeof(key->type_data)); | |
315 | ||
316 | #ifdef KEY_DEBUGGING | |
317 | key->magic = KEY_DEBUG_MAGIC; | |
318 | #endif | |
319 | ||
29db9190 | 320 | /* let the security module know about the key */ |
d84f4f99 | 321 | ret = security_key_alloc(key, cred, flags); |
29db9190 DH |
322 | if (ret < 0) |
323 | goto security_error; | |
324 | ||
1da177e4 LT |
325 | /* publish the key by giving it a serial number */ |
326 | atomic_inc(&user->nkeys); | |
327 | key_alloc_serial(key); | |
328 | ||
29db9190 | 329 | error: |
1da177e4 LT |
330 | return key; |
331 | ||
29db9190 DH |
332 | security_error: |
333 | kfree(key->description); | |
1da177e4 | 334 | kmem_cache_free(key_jar, key); |
7e047ef5 | 335 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
1da177e4 LT |
336 | spin_lock(&user->lock); |
337 | user->qnkeys--; | |
338 | user->qnbytes -= quotalen; | |
339 | spin_unlock(&user->lock); | |
340 | } | |
341 | key_user_put(user); | |
29db9190 DH |
342 | key = ERR_PTR(ret); |
343 | goto error; | |
344 | ||
345 | no_memory_3: | |
346 | kmem_cache_free(key_jar, key); | |
347 | no_memory_2: | |
7e047ef5 | 348 | if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) { |
29db9190 DH |
349 | spin_lock(&user->lock); |
350 | user->qnkeys--; | |
351 | user->qnbytes -= quotalen; | |
352 | spin_unlock(&user->lock); | |
353 | } | |
354 | key_user_put(user); | |
355 | no_memory_1: | |
1da177e4 LT |
356 | key = ERR_PTR(-ENOMEM); |
357 | goto error; | |
358 | ||
29db9190 | 359 | no_quota: |
1da177e4 LT |
360 | spin_unlock(&user->lock); |
361 | key_user_put(user); | |
362 | key = ERR_PTR(-EDQUOT); | |
363 | goto error; | |
a8b17ed0 | 364 | } |
1da177e4 LT |
365 | EXPORT_SYMBOL(key_alloc); |
366 | ||
973c9f4f DH |
367 | /** |
368 | * key_payload_reserve - Adjust data quota reservation for the key's payload | |
369 | * @key: The key to make the reservation for. | |
370 | * @datalen: The amount of data payload the caller now wants. | |
371 | * | |
372 | * Adjust the amount of the owning user's key data quota that a key reserves. | |
373 | * If the amount is increased, then -EDQUOT may be returned if there isn't | |
374 | * enough free quota available. | |
375 | * | |
376 | * If successful, 0 is returned. | |
1da177e4 LT |
377 | */ |
378 | int key_payload_reserve(struct key *key, size_t datalen) | |
379 | { | |
c5b60b5e | 380 | int delta = (int)datalen - key->datalen; |
1da177e4 LT |
381 | int ret = 0; |
382 | ||
383 | key_check(key); | |
384 | ||
385 | /* contemplate the quota adjustment */ | |
76d8aeab | 386 | if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { |
0b77f5bf DH |
387 | unsigned maxbytes = (key->user->uid == 0) ? |
388 | key_quota_root_maxbytes : key_quota_maxbytes; | |
389 | ||
1da177e4 LT |
390 | spin_lock(&key->user->lock); |
391 | ||
392 | if (delta > 0 && | |
0b77f5bf DH |
393 | (key->user->qnbytes + delta >= maxbytes || |
394 | key->user->qnbytes + delta < key->user->qnbytes)) { | |
1da177e4 LT |
395 | ret = -EDQUOT; |
396 | } | |
397 | else { | |
398 | key->user->qnbytes += delta; | |
399 | key->quotalen += delta; | |
400 | } | |
401 | spin_unlock(&key->user->lock); | |
402 | } | |
403 | ||
404 | /* change the recorded data length if that didn't generate an error */ | |
405 | if (ret == 0) | |
406 | key->datalen = datalen; | |
407 | ||
408 | return ret; | |
a8b17ed0 | 409 | } |
1da177e4 LT |
410 | EXPORT_SYMBOL(key_payload_reserve); |
411 | ||
1da177e4 | 412 | /* |
973c9f4f DH |
413 | * Instantiate a key and link it into the target keyring atomically. Must be |
414 | * called with the target keyring's semaphore writelocked. The target key's | |
415 | * semaphore need not be locked as instantiation is serialised by | |
416 | * key_construction_mutex. | |
1da177e4 LT |
417 | */ |
418 | static int __key_instantiate_and_link(struct key *key, | |
419 | const void *data, | |
420 | size_t datalen, | |
3e30148c | 421 | struct key *keyring, |
f70e2e06 | 422 | struct key *authkey, |
ceb73c12 | 423 | unsigned long *_prealloc) |
1da177e4 LT |
424 | { |
425 | int ret, awaken; | |
426 | ||
427 | key_check(key); | |
428 | key_check(keyring); | |
429 | ||
430 | awaken = 0; | |
431 | ret = -EBUSY; | |
432 | ||
76181c13 | 433 | mutex_lock(&key_construction_mutex); |
1da177e4 LT |
434 | |
435 | /* can't instantiate twice */ | |
76d8aeab | 436 | if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { |
1da177e4 LT |
437 | /* instantiate the key */ |
438 | ret = key->type->instantiate(key, data, datalen); | |
439 | ||
440 | if (ret == 0) { | |
441 | /* mark the key as being instantiated */ | |
1da177e4 | 442 | atomic_inc(&key->user->nikeys); |
76d8aeab | 443 | set_bit(KEY_FLAG_INSTANTIATED, &key->flags); |
1da177e4 | 444 | |
76d8aeab | 445 | if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) |
1da177e4 | 446 | awaken = 1; |
1da177e4 LT |
447 | |
448 | /* and link it into the destination keyring */ | |
449 | if (keyring) | |
f70e2e06 | 450 | __key_link(keyring, key, _prealloc); |
3e30148c DH |
451 | |
452 | /* disable the authorisation key */ | |
d84f4f99 DH |
453 | if (authkey) |
454 | key_revoke(authkey); | |
1da177e4 LT |
455 | } |
456 | } | |
457 | ||
76181c13 | 458 | mutex_unlock(&key_construction_mutex); |
1da177e4 LT |
459 | |
460 | /* wake up anyone waiting for a key to be constructed */ | |
461 | if (awaken) | |
76181c13 | 462 | wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT); |
1da177e4 LT |
463 | |
464 | return ret; | |
a8b17ed0 | 465 | } |
1da177e4 | 466 | |
973c9f4f DH |
467 | /** |
468 | * key_instantiate_and_link - Instantiate a key and link it into the keyring. | |
469 | * @key: The key to instantiate. | |
470 | * @data: The data to use to instantiate the keyring. | |
471 | * @datalen: The length of @data. | |
472 | * @keyring: Keyring to create a link in on success (or NULL). | |
473 | * @authkey: The authorisation token permitting instantiation. | |
474 | * | |
475 | * Instantiate a key that's in the uninstantiated state using the provided data | |
476 | * and, if successful, link it in to the destination keyring if one is | |
477 | * supplied. | |
478 | * | |
479 | * If successful, 0 is returned, the authorisation token is revoked and anyone | |
480 | * waiting for the key is woken up. If the key was already instantiated, | |
481 | * -EBUSY will be returned. | |
1da177e4 LT |
482 | */ |
483 | int key_instantiate_and_link(struct key *key, | |
484 | const void *data, | |
485 | size_t datalen, | |
3e30148c | 486 | struct key *keyring, |
d84f4f99 | 487 | struct key *authkey) |
1da177e4 | 488 | { |
ceb73c12 | 489 | unsigned long prealloc; |
1da177e4 LT |
490 | int ret; |
491 | ||
f70e2e06 DH |
492 | if (keyring) { |
493 | ret = __key_link_begin(keyring, key->type, key->description, | |
494 | &prealloc); | |
495 | if (ret < 0) | |
496 | return ret; | |
497 | } | |
1da177e4 | 498 | |
f70e2e06 DH |
499 | ret = __key_instantiate_and_link(key, data, datalen, keyring, authkey, |
500 | &prealloc); | |
1da177e4 LT |
501 | |
502 | if (keyring) | |
f70e2e06 | 503 | __key_link_end(keyring, key->type, prealloc); |
1da177e4 LT |
504 | |
505 | return ret; | |
a8b17ed0 | 506 | } |
1da177e4 LT |
507 | |
508 | EXPORT_SYMBOL(key_instantiate_and_link); | |
509 | ||
973c9f4f | 510 | /** |
fdd1b945 | 511 | * key_reject_and_link - Negatively instantiate a key and link it into the keyring. |
973c9f4f DH |
512 | * @key: The key to instantiate. |
513 | * @timeout: The timeout on the negative key. | |
fdd1b945 | 514 | * @error: The error to return when the key is hit. |
973c9f4f DH |
515 | * @keyring: Keyring to create a link in on success (or NULL). |
516 | * @authkey: The authorisation token permitting instantiation. | |
517 | * | |
518 | * Negatively instantiate a key that's in the uninstantiated state and, if | |
fdd1b945 DH |
519 | * successful, set its timeout and stored error and link it in to the |
520 | * destination keyring if one is supplied. The key and any links to the key | |
521 | * will be automatically garbage collected after the timeout expires. | |
973c9f4f DH |
522 | * |
523 | * Negative keys are used to rate limit repeated request_key() calls by causing | |
fdd1b945 DH |
524 | * them to return the stored error code (typically ENOKEY) until the negative |
525 | * key expires. | |
973c9f4f DH |
526 | * |
527 | * If successful, 0 is returned, the authorisation token is revoked and anyone | |
528 | * waiting for the key is woken up. If the key was already instantiated, | |
529 | * -EBUSY will be returned. | |
1da177e4 | 530 | */ |
fdd1b945 | 531 | int key_reject_and_link(struct key *key, |
1da177e4 | 532 | unsigned timeout, |
fdd1b945 | 533 | unsigned error, |
3e30148c | 534 | struct key *keyring, |
d84f4f99 | 535 | struct key *authkey) |
1da177e4 | 536 | { |
ceb73c12 | 537 | unsigned long prealloc; |
1da177e4 | 538 | struct timespec now; |
f70e2e06 | 539 | int ret, awaken, link_ret = 0; |
1da177e4 LT |
540 | |
541 | key_check(key); | |
542 | key_check(keyring); | |
543 | ||
544 | awaken = 0; | |
545 | ret = -EBUSY; | |
546 | ||
547 | if (keyring) | |
f70e2e06 DH |
548 | link_ret = __key_link_begin(keyring, key->type, |
549 | key->description, &prealloc); | |
1da177e4 | 550 | |
76181c13 | 551 | mutex_lock(&key_construction_mutex); |
1da177e4 LT |
552 | |
553 | /* can't instantiate twice */ | |
76d8aeab | 554 | if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { |
1da177e4 | 555 | /* mark the key as being negatively instantiated */ |
1da177e4 | 556 | atomic_inc(&key->user->nikeys); |
76d8aeab DH |
557 | set_bit(KEY_FLAG_NEGATIVE, &key->flags); |
558 | set_bit(KEY_FLAG_INSTANTIATED, &key->flags); | |
fdd1b945 | 559 | key->type_data.reject_error = -error; |
1da177e4 LT |
560 | now = current_kernel_time(); |
561 | key->expiry = now.tv_sec + timeout; | |
c08ef808 | 562 | key_schedule_gc(key->expiry + key_gc_delay); |
1da177e4 | 563 | |
76d8aeab | 564 | if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) |
1da177e4 | 565 | awaken = 1; |
1da177e4 | 566 | |
1da177e4 LT |
567 | ret = 0; |
568 | ||
569 | /* and link it into the destination keyring */ | |
f70e2e06 DH |
570 | if (keyring && link_ret == 0) |
571 | __key_link(keyring, key, &prealloc); | |
3e30148c DH |
572 | |
573 | /* disable the authorisation key */ | |
d84f4f99 DH |
574 | if (authkey) |
575 | key_revoke(authkey); | |
1da177e4 LT |
576 | } |
577 | ||
76181c13 | 578 | mutex_unlock(&key_construction_mutex); |
1da177e4 LT |
579 | |
580 | if (keyring) | |
f70e2e06 | 581 | __key_link_end(keyring, key->type, prealloc); |
1da177e4 LT |
582 | |
583 | /* wake up anyone waiting for a key to be constructed */ | |
584 | if (awaken) | |
76181c13 | 585 | wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT); |
1da177e4 | 586 | |
f70e2e06 | 587 | return ret == 0 ? link_ret : ret; |
a8b17ed0 | 588 | } |
fdd1b945 | 589 | EXPORT_SYMBOL(key_reject_and_link); |
1da177e4 | 590 | |
973c9f4f DH |
591 | /** |
592 | * key_put - Discard a reference to a key. | |
593 | * @key: The key to discard a reference from. | |
594 | * | |
595 | * Discard a reference to a key, and when all the references are gone, we | |
596 | * schedule the cleanup task to come and pull it out of the tree in process | |
597 | * context at some later time. | |
1da177e4 LT |
598 | */ |
599 | void key_put(struct key *key) | |
600 | { | |
601 | if (key) { | |
602 | key_check(key); | |
603 | ||
604 | if (atomic_dec_and_test(&key->usage)) | |
b072e9bc | 605 | queue_work(system_nrt_wq, &key_gc_unused_work); |
1da177e4 | 606 | } |
a8b17ed0 | 607 | } |
1da177e4 LT |
608 | EXPORT_SYMBOL(key_put); |
609 | ||
1da177e4 | 610 | /* |
973c9f4f | 611 | * Find a key by its serial number. |
1da177e4 LT |
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 | ||
973c9f4f | 633 | not_found: |
1da177e4 LT |
634 | key = ERR_PTR(-ENOKEY); |
635 | goto error; | |
636 | ||
973c9f4f | 637 | found: |
5593122e DH |
638 | /* pretend it doesn't exist if it is awaiting deletion */ |
639 | if (atomic_read(&key->usage) == 0) | |
1da177e4 LT |
640 | goto not_found; |
641 | ||
642 | /* this races with key_put(), but that doesn't matter since key_put() | |
643 | * doesn't actually change the key | |
644 | */ | |
645 | atomic_inc(&key->usage); | |
646 | ||
973c9f4f | 647 | error: |
1da177e4 LT |
648 | spin_unlock(&key_serial_lock); |
649 | return key; | |
a8b17ed0 | 650 | } |
1da177e4 | 651 | |
1da177e4 | 652 | /* |
973c9f4f DH |
653 | * Find and lock the specified key type against removal. |
654 | * | |
655 | * We return with the sem read-locked if successful. If the type wasn't | |
656 | * available -ENOKEY is returned instead. | |
1da177e4 LT |
657 | */ |
658 | struct key_type *key_type_lookup(const char *type) | |
659 | { | |
660 | struct key_type *ktype; | |
661 | ||
662 | down_read(&key_types_sem); | |
663 | ||
664 | /* look up the key type to see if it's one of the registered kernel | |
665 | * types */ | |
666 | list_for_each_entry(ktype, &key_types_list, link) { | |
667 | if (strcmp(ktype->name, type) == 0) | |
668 | goto found_kernel_type; | |
669 | } | |
670 | ||
671 | up_read(&key_types_sem); | |
672 | ktype = ERR_PTR(-ENOKEY); | |
673 | ||
973c9f4f | 674 | found_kernel_type: |
1da177e4 | 675 | return ktype; |
a8b17ed0 | 676 | } |
1da177e4 | 677 | |
1da177e4 | 678 | /* |
973c9f4f | 679 | * Unlock a key type locked by key_type_lookup(). |
1da177e4 LT |
680 | */ |
681 | void key_type_put(struct key_type *ktype) | |
682 | { | |
683 | up_read(&key_types_sem); | |
a8b17ed0 | 684 | } |
1da177e4 | 685 | |
1da177e4 | 686 | /* |
973c9f4f DH |
687 | * Attempt to update an existing key. |
688 | * | |
689 | * The key is given to us with an incremented refcount that we need to discard | |
690 | * if we get an error. | |
1da177e4 | 691 | */ |
664cceb0 DH |
692 | static inline key_ref_t __key_update(key_ref_t key_ref, |
693 | const void *payload, size_t plen) | |
1da177e4 | 694 | { |
664cceb0 | 695 | struct key *key = key_ref_to_ptr(key_ref); |
1da177e4 LT |
696 | int ret; |
697 | ||
698 | /* need write permission on the key to update it */ | |
29db9190 DH |
699 | ret = key_permission(key_ref, KEY_WRITE); |
700 | if (ret < 0) | |
1da177e4 LT |
701 | goto error; |
702 | ||
703 | ret = -EEXIST; | |
704 | if (!key->type->update) | |
705 | goto error; | |
706 | ||
707 | down_write(&key->sem); | |
708 | ||
709 | ret = key->type->update(key, payload, plen); | |
76d8aeab | 710 | if (ret == 0) |
1da177e4 | 711 | /* updating a negative key instantiates it */ |
76d8aeab | 712 | clear_bit(KEY_FLAG_NEGATIVE, &key->flags); |
1da177e4 LT |
713 | |
714 | up_write(&key->sem); | |
715 | ||
716 | if (ret < 0) | |
717 | goto error; | |
664cceb0 DH |
718 | out: |
719 | return key_ref; | |
1da177e4 | 720 | |
664cceb0 | 721 | error: |
1da177e4 | 722 | key_put(key); |
664cceb0 | 723 | key_ref = ERR_PTR(ret); |
1da177e4 | 724 | goto out; |
a8b17ed0 | 725 | } |
1da177e4 | 726 | |
973c9f4f DH |
727 | /** |
728 | * key_create_or_update - Update or create and instantiate a key. | |
729 | * @keyring_ref: A pointer to the destination keyring with possession flag. | |
730 | * @type: The type of key. | |
731 | * @description: The searchable description for the key. | |
732 | * @payload: The data to use to instantiate or update the key. | |
733 | * @plen: The length of @payload. | |
734 | * @perm: The permissions mask for a new key. | |
735 | * @flags: The quota flags for a new key. | |
736 | * | |
737 | * Search the destination keyring for a key of the same description and if one | |
738 | * is found, update it, otherwise create and instantiate a new one and create a | |
739 | * link to it from that keyring. | |
740 | * | |
741 | * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be | |
742 | * concocted. | |
743 | * | |
744 | * Returns a pointer to the new key if successful, -ENODEV if the key type | |
745 | * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the | |
746 | * caller isn't permitted to modify the keyring or the LSM did not permit | |
747 | * creation of the key. | |
748 | * | |
749 | * On success, the possession flag from the keyring ref will be tacked on to | |
750 | * the key ref before it is returned. | |
1da177e4 | 751 | */ |
664cceb0 DH |
752 | key_ref_t key_create_or_update(key_ref_t keyring_ref, |
753 | const char *type, | |
754 | const char *description, | |
755 | const void *payload, | |
756 | size_t plen, | |
6b79ccb5 | 757 | key_perm_t perm, |
7e047ef5 | 758 | unsigned long flags) |
1da177e4 | 759 | { |
ceb73c12 | 760 | unsigned long prealloc; |
d84f4f99 | 761 | const struct cred *cred = current_cred(); |
1da177e4 | 762 | struct key_type *ktype; |
664cceb0 | 763 | struct key *keyring, *key = NULL; |
664cceb0 | 764 | key_ref_t key_ref; |
1da177e4 LT |
765 | int ret; |
766 | ||
1da177e4 LT |
767 | /* look up the key type to see if it's one of the registered kernel |
768 | * types */ | |
769 | ktype = key_type_lookup(type); | |
770 | if (IS_ERR(ktype)) { | |
664cceb0 | 771 | key_ref = ERR_PTR(-ENODEV); |
1da177e4 LT |
772 | goto error; |
773 | } | |
774 | ||
664cceb0 | 775 | key_ref = ERR_PTR(-EINVAL); |
1da177e4 LT |
776 | if (!ktype->match || !ktype->instantiate) |
777 | goto error_2; | |
778 | ||
664cceb0 DH |
779 | keyring = key_ref_to_ptr(keyring_ref); |
780 | ||
781 | key_check(keyring); | |
782 | ||
c3a9d654 DH |
783 | key_ref = ERR_PTR(-ENOTDIR); |
784 | if (keyring->type != &key_type_keyring) | |
785 | goto error_2; | |
786 | ||
f70e2e06 DH |
787 | ret = __key_link_begin(keyring, ktype, description, &prealloc); |
788 | if (ret < 0) | |
789 | goto error_2; | |
664cceb0 DH |
790 | |
791 | /* if we're going to allocate a new key, we're going to have | |
792 | * to modify the keyring */ | |
29db9190 DH |
793 | ret = key_permission(keyring_ref, KEY_WRITE); |
794 | if (ret < 0) { | |
795 | key_ref = ERR_PTR(ret); | |
664cceb0 | 796 | goto error_3; |
29db9190 | 797 | } |
664cceb0 | 798 | |
1d9b7d97 DH |
799 | /* if it's possible to update this type of key, search for an existing |
800 | * key of the same type and description in the destination keyring and | |
801 | * update that instead if possible | |
1da177e4 | 802 | */ |
1d9b7d97 DH |
803 | if (ktype->update) { |
804 | key_ref = __keyring_search_one(keyring_ref, ktype, description, | |
805 | 0); | |
806 | if (!IS_ERR(key_ref)) | |
807 | goto found_matching_key; | |
808 | } | |
1da177e4 | 809 | |
6b79ccb5 AR |
810 | /* if the client doesn't provide, decide on the permissions we want */ |
811 | if (perm == KEY_PERM_UNDEF) { | |
812 | perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR; | |
813 | perm |= KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK | KEY_USR_SETATTR; | |
1da177e4 | 814 | |
6b79ccb5 AR |
815 | if (ktype->read) |
816 | perm |= KEY_POS_READ | KEY_USR_READ; | |
1da177e4 | 817 | |
6b79ccb5 AR |
818 | if (ktype == &key_type_keyring || ktype->update) |
819 | perm |= KEY_USR_WRITE; | |
820 | } | |
1da177e4 LT |
821 | |
822 | /* allocate a new key */ | |
d84f4f99 DH |
823 | key = key_alloc(ktype, description, cred->fsuid, cred->fsgid, cred, |
824 | perm, flags); | |
1da177e4 | 825 | if (IS_ERR(key)) { |
e231c2ee | 826 | key_ref = ERR_CAST(key); |
1da177e4 LT |
827 | goto error_3; |
828 | } | |
829 | ||
830 | /* instantiate it and link it into the target keyring */ | |
f70e2e06 DH |
831 | ret = __key_instantiate_and_link(key, payload, plen, keyring, NULL, |
832 | &prealloc); | |
1da177e4 LT |
833 | if (ret < 0) { |
834 | key_put(key); | |
664cceb0 DH |
835 | key_ref = ERR_PTR(ret); |
836 | goto error_3; | |
1da177e4 LT |
837 | } |
838 | ||
664cceb0 DH |
839 | key_ref = make_key_ref(key, is_key_possessed(keyring_ref)); |
840 | ||
1da177e4 | 841 | error_3: |
f70e2e06 | 842 | __key_link_end(keyring, ktype, prealloc); |
1da177e4 LT |
843 | error_2: |
844 | key_type_put(ktype); | |
845 | error: | |
664cceb0 | 846 | return key_ref; |
1da177e4 LT |
847 | |
848 | found_matching_key: | |
849 | /* we found a matching key, so we're going to try to update it | |
850 | * - we can drop the locks first as we have the key pinned | |
851 | */ | |
f70e2e06 | 852 | __key_link_end(keyring, ktype, prealloc); |
1da177e4 LT |
853 | key_type_put(ktype); |
854 | ||
664cceb0 | 855 | key_ref = __key_update(key_ref, payload, plen); |
1da177e4 | 856 | goto error; |
a8b17ed0 | 857 | } |
1da177e4 LT |
858 | EXPORT_SYMBOL(key_create_or_update); |
859 | ||
973c9f4f DH |
860 | /** |
861 | * key_update - Update a key's contents. | |
862 | * @key_ref: The pointer (plus possession flag) to the key. | |
863 | * @payload: The data to be used to update the key. | |
864 | * @plen: The length of @payload. | |
865 | * | |
866 | * Attempt to update the contents of a key with the given payload data. The | |
867 | * caller must be granted Write permission on the key. Negative keys can be | |
868 | * instantiated by this method. | |
869 | * | |
870 | * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key | |
871 | * type does not support updating. The key type may return other errors. | |
1da177e4 | 872 | */ |
664cceb0 | 873 | int key_update(key_ref_t key_ref, const void *payload, size_t plen) |
1da177e4 | 874 | { |
664cceb0 | 875 | struct key *key = key_ref_to_ptr(key_ref); |
1da177e4 LT |
876 | int ret; |
877 | ||
878 | key_check(key); | |
879 | ||
880 | /* the key must be writable */ | |
29db9190 DH |
881 | ret = key_permission(key_ref, KEY_WRITE); |
882 | if (ret < 0) | |
1da177e4 LT |
883 | goto error; |
884 | ||
885 | /* attempt to update it if supported */ | |
886 | ret = -EOPNOTSUPP; | |
887 | if (key->type->update) { | |
888 | down_write(&key->sem); | |
1da177e4 | 889 | |
29db9190 | 890 | ret = key->type->update(key, payload, plen); |
76d8aeab | 891 | if (ret == 0) |
1da177e4 | 892 | /* updating a negative key instantiates it */ |
76d8aeab | 893 | clear_bit(KEY_FLAG_NEGATIVE, &key->flags); |
1da177e4 LT |
894 | |
895 | up_write(&key->sem); | |
896 | } | |
897 | ||
898 | error: | |
899 | return ret; | |
a8b17ed0 | 900 | } |
1da177e4 LT |
901 | EXPORT_SYMBOL(key_update); |
902 | ||
973c9f4f DH |
903 | /** |
904 | * key_revoke - Revoke a key. | |
905 | * @key: The key to be revoked. | |
906 | * | |
907 | * Mark a key as being revoked and ask the type to free up its resources. The | |
908 | * revocation timeout is set and the key and all its links will be | |
909 | * automatically garbage collected after key_gc_delay amount of time if they | |
910 | * are not manually dealt with first. | |
1da177e4 LT |
911 | */ |
912 | void key_revoke(struct key *key) | |
913 | { | |
5d135440 DH |
914 | struct timespec now; |
915 | time_t time; | |
916 | ||
1da177e4 LT |
917 | key_check(key); |
918 | ||
76181c13 DH |
919 | /* make sure no one's trying to change or use the key when we mark it |
920 | * - we tell lockdep that we might nest because we might be revoking an | |
921 | * authorisation key whilst holding the sem on a key we've just | |
922 | * instantiated | |
923 | */ | |
924 | down_write_nested(&key->sem, 1); | |
925 | if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags) && | |
926 | key->type->revoke) | |
04c567d9 DH |
927 | key->type->revoke(key); |
928 | ||
5d135440 DH |
929 | /* set the death time to no more than the expiry time */ |
930 | now = current_kernel_time(); | |
931 | time = now.tv_sec; | |
932 | if (key->revoked_at == 0 || key->revoked_at > time) { | |
933 | key->revoked_at = time; | |
c08ef808 | 934 | key_schedule_gc(key->revoked_at + key_gc_delay); |
5d135440 DH |
935 | } |
936 | ||
1da177e4 | 937 | up_write(&key->sem); |
a8b17ed0 | 938 | } |
1da177e4 LT |
939 | EXPORT_SYMBOL(key_revoke); |
940 | ||
973c9f4f DH |
941 | /** |
942 | * register_key_type - Register a type of key. | |
943 | * @ktype: The new key type. | |
944 | * | |
945 | * Register a new key type. | |
946 | * | |
947 | * Returns 0 on success or -EEXIST if a type of this name already exists. | |
1da177e4 LT |
948 | */ |
949 | int register_key_type(struct key_type *ktype) | |
950 | { | |
951 | struct key_type *p; | |
952 | int ret; | |
953 | ||
954 | ret = -EEXIST; | |
955 | down_write(&key_types_sem); | |
956 | ||
957 | /* disallow key types with the same name */ | |
958 | list_for_each_entry(p, &key_types_list, link) { | |
959 | if (strcmp(p->name, ktype->name) == 0) | |
960 | goto out; | |
961 | } | |
962 | ||
963 | /* store the type */ | |
964 | list_add(&ktype->link, &key_types_list); | |
965 | ret = 0; | |
966 | ||
973c9f4f | 967 | out: |
1da177e4 LT |
968 | up_write(&key_types_sem); |
969 | return ret; | |
a8b17ed0 | 970 | } |
1da177e4 LT |
971 | EXPORT_SYMBOL(register_key_type); |
972 | ||
973c9f4f DH |
973 | /** |
974 | * unregister_key_type - Unregister a type of key. | |
975 | * @ktype: The key type. | |
976 | * | |
977 | * Unregister a key type and mark all the extant keys of this type as dead. | |
978 | * Those keys of this type are then destroyed to get rid of their payloads and | |
979 | * they and their links will be garbage collected as soon as possible. | |
1da177e4 LT |
980 | */ |
981 | void unregister_key_type(struct key_type *ktype) | |
982 | { | |
983 | struct rb_node *_n; | |
984 | struct key *key; | |
985 | ||
986 | down_write(&key_types_sem); | |
987 | ||
988 | /* withdraw the key type */ | |
989 | list_del_init(&ktype->link); | |
990 | ||
76d8aeab | 991 | /* mark all the keys of this type dead */ |
1da177e4 LT |
992 | spin_lock(&key_serial_lock); |
993 | ||
994 | for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { | |
995 | key = rb_entry(_n, struct key, serial_node); | |
996 | ||
f041ae2f | 997 | if (key->type == ktype) { |
76d8aeab | 998 | key->type = &key_type_dead; |
f041ae2f DH |
999 | set_bit(KEY_FLAG_DEAD, &key->flags); |
1000 | } | |
76d8aeab DH |
1001 | } |
1002 | ||
1003 | spin_unlock(&key_serial_lock); | |
1004 | ||
1005 | /* make sure everyone revalidates their keys */ | |
b2b18660 | 1006 | synchronize_rcu(); |
76d8aeab DH |
1007 | |
1008 | /* we should now be able to destroy the payloads of all the keys of | |
1009 | * this type with impunity */ | |
1010 | spin_lock(&key_serial_lock); | |
1da177e4 | 1011 | |
76d8aeab DH |
1012 | for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { |
1013 | key = rb_entry(_n, struct key, serial_node); | |
1da177e4 | 1014 | |
76d8aeab DH |
1015 | if (key->type == ktype) { |
1016 | if (ktype->destroy) | |
1017 | ktype->destroy(key); | |
a7807a32 | 1018 | memset(&key->payload, KEY_DESTROY, sizeof(key->payload)); |
76d8aeab | 1019 | } |
1da177e4 LT |
1020 | } |
1021 | ||
1022 | spin_unlock(&key_serial_lock); | |
1023 | up_write(&key_types_sem); | |
1024 | ||
5d135440 | 1025 | key_schedule_gc(0); |
a8b17ed0 | 1026 | } |
1da177e4 LT |
1027 | EXPORT_SYMBOL(unregister_key_type); |
1028 | ||
1da177e4 | 1029 | /* |
973c9f4f | 1030 | * Initialise the key management state. |
1da177e4 LT |
1031 | */ |
1032 | void __init key_init(void) | |
1033 | { | |
1034 | /* allocate a slab in which we can store keys */ | |
1035 | key_jar = kmem_cache_create("key_jar", sizeof(struct key), | |
20c2df83 | 1036 | 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1da177e4 LT |
1037 | |
1038 | /* add the special key types */ | |
1039 | list_add_tail(&key_type_keyring.link, &key_types_list); | |
1040 | list_add_tail(&key_type_dead.link, &key_types_list); | |
1041 | list_add_tail(&key_type_user.link, &key_types_list); | |
1042 | ||
1043 | /* record the root user tracking */ | |
1044 | rb_link_node(&root_key_user.node, | |
1045 | NULL, | |
1046 | &key_user_tree.rb_node); | |
1047 | ||
1048 | rb_insert_color(&root_key_user.node, | |
1049 | &key_user_tree); | |
a8b17ed0 | 1050 | } |