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