blob: 51f8515573894f93103c802cad0173e7f53e23b2 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* key.c: basic authentication token and access key management
2 *
David Howells3dccff82006-03-25 03:06:51 -08003 * Copyright (C) 2004-6 Red Hat, Inc. All Rights Reserved.
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 * 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>
14#include <linux/sched.h>
15#include <linux/slab.h>
David Howells29db9192005-10-30 15:02:44 -080016#include <linux/security.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/workqueue.h>
18#include <linux/err.h>
19#include "internal.h"
20
21static kmem_cache_t *key_jar;
22static key_serial_t key_serial_next = 3;
23struct rb_root key_serial_tree; /* tree of keys indexed by serial */
24DEFINE_SPINLOCK(key_serial_lock);
25
26struct rb_root key_user_tree; /* tree of quota records indexed by UID */
27DEFINE_SPINLOCK(key_user_lock);
28
29static LIST_HEAD(key_types_list);
30static DECLARE_RWSEM(key_types_sem);
31
32static void key_cleanup(void *data);
33static DECLARE_WORK(key_cleanup_task, key_cleanup, NULL);
34
35/* we serialise key instantiation and link */
36DECLARE_RWSEM(key_construction_sem);
37
38/* any key who's type gets unegistered will be re-typed to this */
Adrian Bunk1ae8f402006-01-06 00:11:25 -080039static struct key_type key_type_dead = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 .name = "dead",
41};
42
43#ifdef KEY_DEBUGGING
44void __key_check(const struct key *key)
45{
46 printk("__key_check: key %p {%08x} should be {%08x}\n",
47 key, key->magic, KEY_DEBUG_MAGIC);
48 BUG();
49}
50#endif
51
52/*****************************************************************************/
53/*
54 * get the key quota record for a user, allocating a new record if one doesn't
55 * already exist
56 */
57struct key_user *key_user_lookup(uid_t uid)
58{
59 struct key_user *candidate = NULL, *user;
60 struct rb_node *parent = NULL;
61 struct rb_node **p;
62
63 try_again:
64 p = &key_user_tree.rb_node;
65 spin_lock(&key_user_lock);
66
67 /* search the tree for a user record with a matching UID */
68 while (*p) {
69 parent = *p;
70 user = rb_entry(parent, struct key_user, node);
71
72 if (uid < user->uid)
73 p = &(*p)->rb_left;
74 else if (uid > user->uid)
75 p = &(*p)->rb_right;
76 else
77 goto found;
78 }
79
80 /* if we get here, we failed to find a match in the tree */
81 if (!candidate) {
82 /* allocate a candidate user record if we don't already have
83 * one */
84 spin_unlock(&key_user_lock);
85
86 user = NULL;
87 candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL);
88 if (unlikely(!candidate))
89 goto out;
90
91 /* the allocation may have scheduled, so we need to repeat the
92 * search lest someone else added the record whilst we were
93 * asleep */
94 goto try_again;
95 }
96
97 /* if we get here, then the user record still hadn't appeared on the
98 * second pass - so we use the candidate record */
99 atomic_set(&candidate->usage, 1);
100 atomic_set(&candidate->nkeys, 0);
101 atomic_set(&candidate->nikeys, 0);
102 candidate->uid = uid;
103 candidate->qnkeys = 0;
104 candidate->qnbytes = 0;
105 spin_lock_init(&candidate->lock);
106 INIT_LIST_HEAD(&candidate->consq);
107
108 rb_link_node(&candidate->node, parent, p);
109 rb_insert_color(&candidate->node, &key_user_tree);
110 spin_unlock(&key_user_lock);
111 user = candidate;
112 goto out;
113
114 /* okay - we found a user record for this UID */
115 found:
116 atomic_inc(&user->usage);
117 spin_unlock(&key_user_lock);
Jesper Juhla7f988b2005-11-07 01:01:35 -0800118 kfree(candidate);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 out:
120 return user;
121
122} /* end key_user_lookup() */
123
124/*****************************************************************************/
125/*
126 * dispose of a user structure
127 */
128void key_user_put(struct key_user *user)
129{
130 if (atomic_dec_and_lock(&user->usage, &key_user_lock)) {
131 rb_erase(&user->node, &key_user_tree);
132 spin_unlock(&key_user_lock);
133
134 kfree(user);
135 }
136
137} /* end key_user_put() */
138
139/*****************************************************************************/
140/*
141 * insert a key with a fixed serial number
142 */
143static void __init __key_insert_serial(struct key *key)
144{
145 struct rb_node *parent, **p;
146 struct key *xkey;
147
148 parent = NULL;
149 p = &key_serial_tree.rb_node;
150
151 while (*p) {
152 parent = *p;
153 xkey = rb_entry(parent, struct key, serial_node);
154
155 if (key->serial < xkey->serial)
156 p = &(*p)->rb_left;
157 else if (key->serial > xkey->serial)
158 p = &(*p)->rb_right;
159 else
160 BUG();
161 }
162
163 /* we've found a suitable hole - arrange for this key to occupy it */
164 rb_link_node(&key->serial_node, parent, p);
165 rb_insert_color(&key->serial_node, &key_serial_tree);
166
167} /* end __key_insert_serial() */
168
169/*****************************************************************************/
170/*
171 * assign a key the next unique serial number
172 * - we work through all the serial numbers between 2 and 2^31-1 in turn and
173 * then wrap
174 */
175static inline void key_alloc_serial(struct key *key)
176{
177 struct rb_node *parent, **p;
178 struct key *xkey;
179
180 spin_lock(&key_serial_lock);
181
182 /* propose a likely serial number and look for a hole for it in the
183 * serial number tree */
184 key->serial = key_serial_next;
185 if (key->serial < 3)
186 key->serial = 3;
187 key_serial_next = key->serial + 1;
188
189 parent = NULL;
190 p = &key_serial_tree.rb_node;
191
192 while (*p) {
193 parent = *p;
194 xkey = rb_entry(parent, struct key, serial_node);
195
196 if (key->serial < xkey->serial)
197 p = &(*p)->rb_left;
198 else if (key->serial > xkey->serial)
199 p = &(*p)->rb_right;
200 else
201 goto serial_exists;
202 }
203 goto insert_here;
204
205 /* we found a key with the proposed serial number - walk the tree from
206 * that point looking for the next unused serial number */
207 serial_exists:
208 for (;;) {
209 key->serial = key_serial_next;
210 if (key->serial < 2)
211 key->serial = 2;
212 key_serial_next = key->serial + 1;
213
David Woodhousefed306f2006-04-21 13:16:49 +0100214 if (!rb_parent(parent))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 p = &key_serial_tree.rb_node;
David Woodhousefed306f2006-04-21 13:16:49 +0100216 else if (rb_parent(parent)->rb_left == parent)
217 p = &(rb_parent(parent)->rb_left);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 else
David Woodhousefed306f2006-04-21 13:16:49 +0100219 p = &(rb_parent(parent)->rb_right);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220
221 parent = rb_next(parent);
222 if (!parent)
223 break;
224
225 xkey = rb_entry(parent, struct key, serial_node);
226 if (key->serial < xkey->serial)
227 goto insert_here;
228 }
229
230 /* we've found a suitable hole - arrange for this key to occupy it */
231 insert_here:
232 rb_link_node(&key->serial_node, parent, p);
233 rb_insert_color(&key->serial_node, &key_serial_tree);
234
235 spin_unlock(&key_serial_lock);
236
237} /* end key_alloc_serial() */
238
239/*****************************************************************************/
240/*
241 * allocate a key of the specified type
242 * - update the user's quota to reflect the existence of the key
David Howells8d9067b2006-01-06 00:11:24 -0800243 * - called from a key-type operation with key_types_sem read-locked by
244 * key_create_or_update()
245 * - this prevents unregistration of the key type
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 * - upon return the key is as yet uninstantiated; the caller needs to either
247 * instantiate the key or discard it before returning
248 */
249struct key *key_alloc(struct key_type *type, const char *desc,
Michael LeMayd7200242006-06-22 14:47:17 -0700250 uid_t uid, gid_t gid, struct task_struct *ctx,
251 key_perm_t perm, int not_in_quota)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252{
253 struct key_user *user = NULL;
254 struct key *key;
255 size_t desclen, quotalen;
David Howells29db9192005-10-30 15:02:44 -0800256 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257
258 key = ERR_PTR(-EINVAL);
259 if (!desc || !*desc)
260 goto error;
261
262 desclen = strlen(desc) + 1;
263 quotalen = desclen + type->def_datalen;
264
265 /* get hold of the key tracking for this user */
266 user = key_user_lookup(uid);
267 if (!user)
268 goto no_memory_1;
269
270 /* check that the user's quota permits allocation of another key and
271 * its description */
272 if (!not_in_quota) {
273 spin_lock(&user->lock);
David Howells3dccff82006-03-25 03:06:51 -0800274 if (user->qnkeys + 1 >= KEYQUOTA_MAX_KEYS ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 user->qnbytes + quotalen >= KEYQUOTA_MAX_BYTES
276 )
277 goto no_quota;
278
279 user->qnkeys++;
280 user->qnbytes += quotalen;
281 spin_unlock(&user->lock);
282 }
283
284 /* allocate and initialise the key and its description */
285 key = kmem_cache_alloc(key_jar, SLAB_KERNEL);
286 if (!key)
287 goto no_memory_2;
288
289 if (desc) {
290 key->description = kmalloc(desclen, GFP_KERNEL);
291 if (!key->description)
292 goto no_memory_3;
293
294 memcpy(key->description, desc, desclen);
295 }
296
297 atomic_set(&key->usage, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298 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;
David Howells29db9192005-10-30 15:02:44 -0800309 key->security = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310
311 if (!not_in_quota)
David Howells76d8aea2005-06-23 22:00:49 -0700312 key->flags |= 1 << KEY_FLAG_IN_QUOTA;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313
314 memset(&key->type_data, 0, sizeof(key->type_data));
315
316#ifdef KEY_DEBUGGING
317 key->magic = KEY_DEBUG_MAGIC;
318#endif
319
David Howells29db9192005-10-30 15:02:44 -0800320 /* let the security module know about the key */
Michael LeMayd7200242006-06-22 14:47:17 -0700321 ret = security_key_alloc(key, ctx);
David Howells29db9192005-10-30 15:02:44 -0800322 if (ret < 0)
323 goto security_error;
324
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 /* publish the key by giving it a serial number */
326 atomic_inc(&user->nkeys);
327 key_alloc_serial(key);
328
David Howells29db9192005-10-30 15:02:44 -0800329error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 return key;
331
David Howells29db9192005-10-30 15:02:44 -0800332security_error:
333 kfree(key->description);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 kmem_cache_free(key_jar, key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 if (!not_in_quota) {
336 spin_lock(&user->lock);
337 user->qnkeys--;
338 user->qnbytes -= quotalen;
339 spin_unlock(&user->lock);
340 }
341 key_user_put(user);
David Howells29db9192005-10-30 15:02:44 -0800342 key = ERR_PTR(ret);
343 goto error;
344
345no_memory_3:
346 kmem_cache_free(key_jar, key);
347no_memory_2:
348 if (!not_in_quota) {
349 spin_lock(&user->lock);
350 user->qnkeys--;
351 user->qnbytes -= quotalen;
352 spin_unlock(&user->lock);
353 }
354 key_user_put(user);
355no_memory_1:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356 key = ERR_PTR(-ENOMEM);
357 goto error;
358
David Howells29db9192005-10-30 15:02:44 -0800359no_quota:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 spin_unlock(&user->lock);
361 key_user_put(user);
362 key = ERR_PTR(-EDQUOT);
363 goto error;
364
365} /* end key_alloc() */
366
367EXPORT_SYMBOL(key_alloc);
368
369/*****************************************************************************/
370/*
371 * reserve an amount of quota for the key's payload
372 */
373int key_payload_reserve(struct key *key, size_t datalen)
374{
375 int delta = (int) datalen - key->datalen;
376 int ret = 0;
377
378 key_check(key);
379
380 /* contemplate the quota adjustment */
David Howells76d8aea2005-06-23 22:00:49 -0700381 if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382 spin_lock(&key->user->lock);
383
384 if (delta > 0 &&
385 key->user->qnbytes + delta > KEYQUOTA_MAX_BYTES
386 ) {
387 ret = -EDQUOT;
388 }
389 else {
390 key->user->qnbytes += delta;
391 key->quotalen += delta;
392 }
393 spin_unlock(&key->user->lock);
394 }
395
396 /* change the recorded data length if that didn't generate an error */
397 if (ret == 0)
398 key->datalen = datalen;
399
400 return ret;
401
402} /* end key_payload_reserve() */
403
404EXPORT_SYMBOL(key_payload_reserve);
405
406/*****************************************************************************/
407/*
408 * instantiate a key and link it into the target keyring atomically
409 * - called with the target keyring's semaphore writelocked
410 */
411static int __key_instantiate_and_link(struct key *key,
412 const void *data,
413 size_t datalen,
David Howells3e301482005-06-23 22:00:56 -0700414 struct key *keyring,
415 struct key *instkey)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416{
417 int ret, awaken;
418
419 key_check(key);
420 key_check(keyring);
421
422 awaken = 0;
423 ret = -EBUSY;
424
425 down_write(&key_construction_sem);
426
427 /* can't instantiate twice */
David Howells76d8aea2005-06-23 22:00:49 -0700428 if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429 /* instantiate the key */
430 ret = key->type->instantiate(key, data, datalen);
431
432 if (ret == 0) {
433 /* mark the key as being instantiated */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434 atomic_inc(&key->user->nikeys);
David Howells76d8aea2005-06-23 22:00:49 -0700435 set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436
David Howells76d8aea2005-06-23 22:00:49 -0700437 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438 awaken = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439
440 /* and link it into the destination keyring */
441 if (keyring)
442 ret = __key_link(keyring, key);
David Howells3e301482005-06-23 22:00:56 -0700443
444 /* disable the authorisation key */
445 if (instkey)
446 key_revoke(instkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 }
448 }
449
450 up_write(&key_construction_sem);
451
452 /* wake up anyone waiting for a key to be constructed */
453 if (awaken)
454 wake_up_all(&request_key_conswq);
455
456 return ret;
457
458} /* end __key_instantiate_and_link() */
459
460/*****************************************************************************/
461/*
462 * instantiate a key and link it into the target keyring atomically
463 */
464int key_instantiate_and_link(struct key *key,
465 const void *data,
466 size_t datalen,
David Howells3e301482005-06-23 22:00:56 -0700467 struct key *keyring,
468 struct key *instkey)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469{
470 int ret;
471
472 if (keyring)
473 down_write(&keyring->sem);
474
David Howells3e301482005-06-23 22:00:56 -0700475 ret = __key_instantiate_and_link(key, data, datalen, keyring, instkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476
477 if (keyring)
478 up_write(&keyring->sem);
479
480 return ret;
David Howells3e301482005-06-23 22:00:56 -0700481
Linus Torvalds1da177e2005-04-16 15:20:36 -0700482} /* end key_instantiate_and_link() */
483
484EXPORT_SYMBOL(key_instantiate_and_link);
485
486/*****************************************************************************/
487/*
488 * negatively instantiate a key and link it into the target keyring atomically
489 */
490int key_negate_and_link(struct key *key,
491 unsigned timeout,
David Howells3e301482005-06-23 22:00:56 -0700492 struct key *keyring,
493 struct key *instkey)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494{
495 struct timespec now;
496 int ret, awaken;
497
498 key_check(key);
499 key_check(keyring);
500
501 awaken = 0;
502 ret = -EBUSY;
503
504 if (keyring)
505 down_write(&keyring->sem);
506
507 down_write(&key_construction_sem);
508
509 /* can't instantiate twice */
David Howells76d8aea2005-06-23 22:00:49 -0700510 if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 /* mark the key as being negatively instantiated */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 atomic_inc(&key->user->nikeys);
David Howells76d8aea2005-06-23 22:00:49 -0700513 set_bit(KEY_FLAG_NEGATIVE, &key->flags);
514 set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515 now = current_kernel_time();
516 key->expiry = now.tv_sec + timeout;
517
David Howells76d8aea2005-06-23 22:00:49 -0700518 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519 awaken = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521 ret = 0;
522
523 /* and link it into the destination keyring */
524 if (keyring)
525 ret = __key_link(keyring, key);
David Howells3e301482005-06-23 22:00:56 -0700526
527 /* disable the authorisation key */
528 if (instkey)
529 key_revoke(instkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 }
531
532 up_write(&key_construction_sem);
533
534 if (keyring)
535 up_write(&keyring->sem);
536
537 /* wake up anyone waiting for a key to be constructed */
538 if (awaken)
539 wake_up_all(&request_key_conswq);
540
541 return ret;
542
543} /* end key_negate_and_link() */
544
545EXPORT_SYMBOL(key_negate_and_link);
546
547/*****************************************************************************/
548/*
549 * do cleaning up in process context so that we don't have to disable
550 * interrupts all over the place
551 */
552static void key_cleanup(void *data)
553{
554 struct rb_node *_n;
555 struct key *key;
556
557 go_again:
558 /* look for a dead key in the tree */
559 spin_lock(&key_serial_lock);
560
561 for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
562 key = rb_entry(_n, struct key, serial_node);
563
564 if (atomic_read(&key->usage) == 0)
565 goto found_dead_key;
566 }
567
568 spin_unlock(&key_serial_lock);
569 return;
570
571 found_dead_key:
572 /* we found a dead key - once we've removed it from the tree, we can
573 * drop the lock */
574 rb_erase(&key->serial_node, &key_serial_tree);
575 spin_unlock(&key_serial_lock);
576
David Howells76d8aea2005-06-23 22:00:49 -0700577 key_check(key);
578
David Howells29db9192005-10-30 15:02:44 -0800579 security_key_free(key);
580
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 /* deal with the user's key tracking and quota */
David Howells76d8aea2005-06-23 22:00:49 -0700582 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583 spin_lock(&key->user->lock);
584 key->user->qnkeys--;
585 key->user->qnbytes -= key->quotalen;
586 spin_unlock(&key->user->lock);
587 }
588
589 atomic_dec(&key->user->nkeys);
David Howells76d8aea2005-06-23 22:00:49 -0700590 if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591 atomic_dec(&key->user->nikeys);
592
593 key_user_put(key->user);
594
595 /* now throw away the key memory */
596 if (key->type->destroy)
597 key->type->destroy(key);
598
599 kfree(key->description);
600
601#ifdef KEY_DEBUGGING
602 key->magic = KEY_DEBUG_MAGIC_X;
603#endif
604 kmem_cache_free(key_jar, key);
605
606 /* there may, of course, be more than one key to destroy */
607 goto go_again;
608
609} /* end key_cleanup() */
610
611/*****************************************************************************/
612/*
613 * dispose of a reference to a key
614 * - when all the references are gone, we schedule the cleanup task to come and
615 * pull it out of the tree in definite process context
616 */
617void key_put(struct key *key)
618{
619 if (key) {
620 key_check(key);
621
622 if (atomic_dec_and_test(&key->usage))
623 schedule_work(&key_cleanup_task);
624 }
625
626} /* end key_put() */
627
628EXPORT_SYMBOL(key_put);
629
630/*****************************************************************************/
631/*
632 * find a key by its serial number
633 */
634struct key *key_lookup(key_serial_t id)
635{
636 struct rb_node *n;
637 struct key *key;
638
639 spin_lock(&key_serial_lock);
640
641 /* search the tree for the specified key */
642 n = key_serial_tree.rb_node;
643 while (n) {
644 key = rb_entry(n, struct key, serial_node);
645
646 if (id < key->serial)
647 n = n->rb_left;
648 else if (id > key->serial)
649 n = n->rb_right;
650 else
651 goto found;
652 }
653
654 not_found:
655 key = ERR_PTR(-ENOKEY);
656 goto error;
657
658 found:
David Howells76d8aea2005-06-23 22:00:49 -0700659 /* pretend it doesn't exist if it's dead */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660 if (atomic_read(&key->usage) == 0 ||
David Howells76d8aea2005-06-23 22:00:49 -0700661 test_bit(KEY_FLAG_DEAD, &key->flags) ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662 key->type == &key_type_dead)
663 goto not_found;
664
665 /* this races with key_put(), but that doesn't matter since key_put()
666 * doesn't actually change the key
667 */
668 atomic_inc(&key->usage);
669
670 error:
671 spin_unlock(&key_serial_lock);
672 return key;
673
674} /* end key_lookup() */
675
676/*****************************************************************************/
677/*
678 * find and lock the specified key type against removal
679 * - we return with the sem readlocked
680 */
681struct key_type *key_type_lookup(const char *type)
682{
683 struct key_type *ktype;
684
685 down_read(&key_types_sem);
686
687 /* look up the key type to see if it's one of the registered kernel
688 * types */
689 list_for_each_entry(ktype, &key_types_list, link) {
690 if (strcmp(ktype->name, type) == 0)
691 goto found_kernel_type;
692 }
693
694 up_read(&key_types_sem);
695 ktype = ERR_PTR(-ENOKEY);
696
697 found_kernel_type:
698 return ktype;
699
700} /* end key_type_lookup() */
701
702/*****************************************************************************/
703/*
704 * unlock a key type
705 */
706void key_type_put(struct key_type *ktype)
707{
708 up_read(&key_types_sem);
709
710} /* end key_type_put() */
711
712/*****************************************************************************/
713/*
714 * attempt to update an existing key
715 * - the key has an incremented refcount
716 * - we need to put the key if we get an error
717 */
David Howells664cceb2005-09-28 17:03:15 +0100718static inline key_ref_t __key_update(key_ref_t key_ref,
719 const void *payload, size_t plen)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720{
David Howells664cceb2005-09-28 17:03:15 +0100721 struct key *key = key_ref_to_ptr(key_ref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722 int ret;
723
724 /* need write permission on the key to update it */
David Howells29db9192005-10-30 15:02:44 -0800725 ret = key_permission(key_ref, KEY_WRITE);
726 if (ret < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 goto error;
728
729 ret = -EEXIST;
730 if (!key->type->update)
731 goto error;
732
733 down_write(&key->sem);
734
735 ret = key->type->update(key, payload, plen);
David Howells76d8aea2005-06-23 22:00:49 -0700736 if (ret == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700737 /* updating a negative key instantiates it */
David Howells76d8aea2005-06-23 22:00:49 -0700738 clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739
740 up_write(&key->sem);
741
742 if (ret < 0)
743 goto error;
David Howells664cceb2005-09-28 17:03:15 +0100744out:
745 return key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746
David Howells664cceb2005-09-28 17:03:15 +0100747error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748 key_put(key);
David Howells664cceb2005-09-28 17:03:15 +0100749 key_ref = ERR_PTR(ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750 goto out;
751
752} /* end __key_update() */
753
754/*****************************************************************************/
755/*
756 * search the specified keyring for a key of the same description; if one is
757 * found, update it, otherwise add a new one
758 */
David Howells664cceb2005-09-28 17:03:15 +0100759key_ref_t key_create_or_update(key_ref_t keyring_ref,
760 const char *type,
761 const char *description,
762 const void *payload,
763 size_t plen,
764 int not_in_quota)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765{
766 struct key_type *ktype;
David Howells664cceb2005-09-28 17:03:15 +0100767 struct key *keyring, *key = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768 key_perm_t perm;
David Howells664cceb2005-09-28 17:03:15 +0100769 key_ref_t key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770 int ret;
771
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772 /* look up the key type to see if it's one of the registered kernel
773 * types */
774 ktype = key_type_lookup(type);
775 if (IS_ERR(ktype)) {
David Howells664cceb2005-09-28 17:03:15 +0100776 key_ref = ERR_PTR(-ENODEV);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777 goto error;
778 }
779
David Howells664cceb2005-09-28 17:03:15 +0100780 key_ref = ERR_PTR(-EINVAL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781 if (!ktype->match || !ktype->instantiate)
782 goto error_2;
783
David Howells664cceb2005-09-28 17:03:15 +0100784 keyring = key_ref_to_ptr(keyring_ref);
785
786 key_check(keyring);
787
David Howellsc3a9d652006-04-10 15:15:21 +0100788 key_ref = ERR_PTR(-ENOTDIR);
789 if (keyring->type != &key_type_keyring)
790 goto error_2;
791
David Howells664cceb2005-09-28 17:03:15 +0100792 down_write(&keyring->sem);
793
794 /* if we're going to allocate a new key, we're going to have
795 * to modify the keyring */
David Howells29db9192005-10-30 15:02:44 -0800796 ret = key_permission(keyring_ref, KEY_WRITE);
797 if (ret < 0) {
798 key_ref = ERR_PTR(ret);
David Howells664cceb2005-09-28 17:03:15 +0100799 goto error_3;
David Howells29db9192005-10-30 15:02:44 -0800800 }
David Howells664cceb2005-09-28 17:03:15 +0100801
David Howells1d9b7d92006-03-25 03:06:52 -0800802 /* if it's possible to update this type of key, search for an existing
803 * key of the same type and description in the destination keyring and
804 * update that instead if possible
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805 */
David Howells1d9b7d92006-03-25 03:06:52 -0800806 if (ktype->update) {
807 key_ref = __keyring_search_one(keyring_ref, ktype, description,
808 0);
809 if (!IS_ERR(key_ref))
810 goto found_matching_key;
811 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812
Linus Torvalds1da177e2005-04-16 15:20:36 -0700813 /* decide on the permissions we want */
David Howells29db9192005-10-30 15:02:44 -0800814 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
815 perm |= KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK | KEY_USR_SETATTR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816
817 if (ktype->read)
David Howells664cceb2005-09-28 17:03:15 +0100818 perm |= KEY_POS_READ | KEY_USR_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700819
820 if (ktype == &key_type_keyring || ktype->update)
821 perm |= KEY_USR_WRITE;
822
823 /* allocate a new key */
824 key = key_alloc(ktype, description, current->fsuid, current->fsgid,
Michael LeMayd7200242006-06-22 14:47:17 -0700825 current, perm, not_in_quota);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700826 if (IS_ERR(key)) {
David Howells664cceb2005-09-28 17:03:15 +0100827 key_ref = ERR_PTR(PTR_ERR(key));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828 goto error_3;
829 }
830
831 /* instantiate it and link it into the target keyring */
David Howells3e301482005-06-23 22:00:56 -0700832 ret = __key_instantiate_and_link(key, payload, plen, keyring, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833 if (ret < 0) {
834 key_put(key);
David Howells664cceb2005-09-28 17:03:15 +0100835 key_ref = ERR_PTR(ret);
836 goto error_3;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837 }
838
David Howells664cceb2005-09-28 17:03:15 +0100839 key_ref = make_key_ref(key, is_key_possessed(keyring_ref));
840
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841 error_3:
842 up_write(&keyring->sem);
843 error_2:
844 key_type_put(ktype);
845 error:
David Howells664cceb2005-09-28 17:03:15 +0100846 return key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847
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 */
852 up_write(&keyring->sem);
853 key_type_put(ktype);
854
David Howells664cceb2005-09-28 17:03:15 +0100855 key_ref = __key_update(key_ref, payload, plen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856 goto error;
857
858} /* end key_create_or_update() */
859
860EXPORT_SYMBOL(key_create_or_update);
861
862/*****************************************************************************/
863/*
864 * update a key
865 */
David Howells664cceb2005-09-28 17:03:15 +0100866int key_update(key_ref_t key_ref, const void *payload, size_t plen)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867{
David Howells664cceb2005-09-28 17:03:15 +0100868 struct key *key = key_ref_to_ptr(key_ref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869 int ret;
870
871 key_check(key);
872
873 /* the key must be writable */
David Howells29db9192005-10-30 15:02:44 -0800874 ret = key_permission(key_ref, KEY_WRITE);
875 if (ret < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876 goto error;
877
878 /* attempt to update it if supported */
879 ret = -EOPNOTSUPP;
880 if (key->type->update) {
881 down_write(&key->sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882
David Howells29db9192005-10-30 15:02:44 -0800883 ret = key->type->update(key, payload, plen);
David Howells76d8aea2005-06-23 22:00:49 -0700884 if (ret == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 /* updating a negative key instantiates it */
David Howells76d8aea2005-06-23 22:00:49 -0700886 clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887
888 up_write(&key->sem);
889 }
890
891 error:
892 return ret;
893
894} /* end key_update() */
895
896EXPORT_SYMBOL(key_update);
897
898/*****************************************************************************/
899/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700900 * revoke a key
901 */
902void key_revoke(struct key *key)
903{
904 key_check(key);
905
906 /* make sure no one's trying to change or use the key when we mark
907 * it */
908 down_write(&key->sem);
David Howells76d8aea2005-06-23 22:00:49 -0700909 set_bit(KEY_FLAG_REVOKED, &key->flags);
David Howells04c567d2006-06-22 14:47:18 -0700910
911 if (key->type->revoke)
912 key->type->revoke(key);
913
Linus Torvalds1da177e2005-04-16 15:20:36 -0700914 up_write(&key->sem);
915
916} /* end key_revoke() */
917
918EXPORT_SYMBOL(key_revoke);
919
920/*****************************************************************************/
921/*
922 * register a type of key
923 */
924int register_key_type(struct key_type *ktype)
925{
926 struct key_type *p;
927 int ret;
928
929 ret = -EEXIST;
930 down_write(&key_types_sem);
931
932 /* disallow key types with the same name */
933 list_for_each_entry(p, &key_types_list, link) {
934 if (strcmp(p->name, ktype->name) == 0)
935 goto out;
936 }
937
938 /* store the type */
939 list_add(&ktype->link, &key_types_list);
940 ret = 0;
941
942 out:
943 up_write(&key_types_sem);
944 return ret;
945
946} /* end register_key_type() */
947
948EXPORT_SYMBOL(register_key_type);
949
950/*****************************************************************************/
951/*
952 * unregister a type of key
953 */
954void unregister_key_type(struct key_type *ktype)
955{
956 struct rb_node *_n;
957 struct key *key;
958
959 down_write(&key_types_sem);
960
961 /* withdraw the key type */
962 list_del_init(&ktype->link);
963
David Howells76d8aea2005-06-23 22:00:49 -0700964 /* mark all the keys of this type dead */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965 spin_lock(&key_serial_lock);
966
967 for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
968 key = rb_entry(_n, struct key, serial_node);
969
David Howells76d8aea2005-06-23 22:00:49 -0700970 if (key->type == ktype)
971 key->type = &key_type_dead;
972 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973
David Howells76d8aea2005-06-23 22:00:49 -0700974 spin_unlock(&key_serial_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975
David Howells76d8aea2005-06-23 22:00:49 -0700976 /* make sure everyone revalidates their keys */
Paul E. McKenneyb2b18662005-06-25 14:55:38 -0700977 synchronize_rcu();
David Howells76d8aea2005-06-23 22:00:49 -0700978
979 /* we should now be able to destroy the payloads of all the keys of
980 * this type with impunity */
981 spin_lock(&key_serial_lock);
982
983 for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
984 key = rb_entry(_n, struct key, serial_node);
985
986 if (key->type == ktype) {
987 if (ktype->destroy)
988 ktype->destroy(key);
989 memset(&key->payload, 0xbd, sizeof(key->payload));
990 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700991 }
992
993 spin_unlock(&key_serial_lock);
994 up_write(&key_types_sem);
995
996} /* end unregister_key_type() */
997
998EXPORT_SYMBOL(unregister_key_type);
999
1000/*****************************************************************************/
1001/*
1002 * initialise the key management stuff
1003 */
1004void __init key_init(void)
1005{
1006 /* allocate a slab in which we can store keys */
1007 key_jar = kmem_cache_create("key_jar", sizeof(struct key),
1008 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1009
1010 /* add the special key types */
1011 list_add_tail(&key_type_keyring.link, &key_types_list);
1012 list_add_tail(&key_type_dead.link, &key_types_list);
1013 list_add_tail(&key_type_user.link, &key_types_list);
1014
1015 /* record the root user tracking */
1016 rb_link_node(&root_key_user.node,
1017 NULL,
1018 &key_user_tree.rb_node);
1019
1020 rb_insert_color(&root_key_user.node,
1021 &key_user_tree);
1022
1023 /* record root's user standard keyrings */
1024 key_check(&root_user_keyring);
1025 key_check(&root_session_keyring);
1026
1027 __key_insert_serial(&root_user_keyring);
1028 __key_insert_serial(&root_session_keyring);
1029
1030 keyring_publish_name(&root_user_keyring);
1031 keyring_publish_name(&root_session_keyring);
1032
1033 /* link the two root keyrings together */
1034 key_link(&root_session_keyring, &root_user_keyring);
David Howells76d8aea2005-06-23 22:00:49 -07001035
Linus Torvalds1da177e2005-04-16 15:20:36 -07001036} /* end key_init() */