blob: e50d264c9ad136a370c5547880b7394608cb39c5 [file] [log] [blame]
David Howells76181c12007-10-16 23:29:46 -07001/* Basic authentication token and access key management
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 *
David Howells69664cf2008-04-29 01:01:31 -07003 * Copyright (C) 2004-2008 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>
Randy Dunlapa7807a32006-06-27 02:53:54 -070014#include <linux/poison.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/sched.h>
16#include <linux/slab.h>
David Howells29db9192005-10-30 15:02:44 -080017#include <linux/security.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/workqueue.h>
Michael LeMaye51f6d32006-06-26 00:24:54 -070019#include <linux/random.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include <linux/err.h>
Serge E. Hallyn1d1e9752009-02-26 18:27:38 -060021#include <linux/user_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include "internal.h"
23
Christoph Lametere18b8902006-12-06 20:33:20 -080024static struct kmem_cache *key_jar;
Linus Torvalds1da177e2005-04-16 15:20:36 -070025struct rb_root key_serial_tree; /* tree of keys indexed by serial */
26DEFINE_SPINLOCK(key_serial_lock);
27
28struct rb_root key_user_tree; /* tree of quota records indexed by UID */
29DEFINE_SPINLOCK(key_user_lock);
30
David Howells0b77f5b2008-04-29 01:01:32 -070031unsigned int key_quota_root_maxkeys = 200; /* root's key count quota */
32unsigned int key_quota_root_maxbytes = 20000; /* root's key space quota */
33unsigned int key_quota_maxkeys = 200; /* general key count quota */
34unsigned int key_quota_maxbytes = 20000; /* general key space quota */
35
Linus Torvalds1da177e2005-04-16 15:20:36 -070036static LIST_HEAD(key_types_list);
37static DECLARE_RWSEM(key_types_sem);
38
David Howells65f27f32006-11-22 14:55:48 +000039static void key_cleanup(struct work_struct *work);
40static DECLARE_WORK(key_cleanup_task, key_cleanup);
Linus Torvalds1da177e2005-04-16 15:20:36 -070041
42/* we serialise key instantiation and link */
David Howells76181c12007-10-16 23:29:46 -070043DEFINE_MUTEX(key_construction_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070044
45/* any key who's type gets unegistered will be re-typed to this */
Adrian Bunk1ae8f402006-01-06 00:11:25 -080046static struct key_type key_type_dead = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070047 .name = "dead",
48};
49
50#ifdef KEY_DEBUGGING
51void __key_check(const struct key *key)
52{
53 printk("__key_check: key %p {%08x} should be {%08x}\n",
54 key, key->magic, KEY_DEBUG_MAGIC);
55 BUG();
56}
57#endif
58
59/*****************************************************************************/
60/*
61 * get the key quota record for a user, allocating a new record if one doesn't
62 * already exist
63 */
Serge E. Hallyn1d1e9752009-02-26 18:27:38 -060064struct key_user *key_user_lookup(uid_t uid, struct user_namespace *user_ns)
Linus Torvalds1da177e2005-04-16 15:20:36 -070065{
66 struct key_user *candidate = NULL, *user;
67 struct rb_node *parent = NULL;
68 struct rb_node **p;
69
70 try_again:
71 p = &key_user_tree.rb_node;
72 spin_lock(&key_user_lock);
73
74 /* search the tree for a user record with a matching UID */
75 while (*p) {
76 parent = *p;
77 user = rb_entry(parent, struct key_user, node);
78
79 if (uid < user->uid)
80 p = &(*p)->rb_left;
81 else if (uid > user->uid)
82 p = &(*p)->rb_right;
Serge E. Hallyn1d1e9752009-02-26 18:27:38 -060083 else if (user_ns < user->user_ns)
84 p = &(*p)->rb_left;
85 else if (user_ns > user->user_ns)
86 p = &(*p)->rb_right;
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 else
88 goto found;
89 }
90
91 /* if we get here, we failed to find a match in the tree */
92 if (!candidate) {
93 /* allocate a candidate user record if we don't already have
94 * one */
95 spin_unlock(&key_user_lock);
96
97 user = NULL;
98 candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL);
99 if (unlikely(!candidate))
100 goto out;
101
102 /* the allocation may have scheduled, so we need to repeat the
103 * search lest someone else added the record whilst we were
104 * asleep */
105 goto try_again;
106 }
107
108 /* if we get here, then the user record still hadn't appeared on the
109 * second pass - so we use the candidate record */
110 atomic_set(&candidate->usage, 1);
111 atomic_set(&candidate->nkeys, 0);
112 atomic_set(&candidate->nikeys, 0);
113 candidate->uid = uid;
Serge E. Hallyn1d1e9752009-02-26 18:27:38 -0600114 candidate->user_ns = get_user_ns(user_ns);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 candidate->qnkeys = 0;
116 candidate->qnbytes = 0;
117 spin_lock_init(&candidate->lock);
David Howells76181c12007-10-16 23:29:46 -0700118 mutex_init(&candidate->cons_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119
120 rb_link_node(&candidate->node, parent, p);
121 rb_insert_color(&candidate->node, &key_user_tree);
122 spin_unlock(&key_user_lock);
123 user = candidate;
124 goto out;
125
126 /* okay - we found a user record for this UID */
127 found:
128 atomic_inc(&user->usage);
129 spin_unlock(&key_user_lock);
Jesper Juhla7f988b2005-11-07 01:01:35 -0800130 kfree(candidate);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 out:
132 return user;
133
134} /* end key_user_lookup() */
135
136/*****************************************************************************/
137/*
138 * dispose of a user structure
139 */
140void key_user_put(struct key_user *user)
141{
142 if (atomic_dec_and_lock(&user->usage, &key_user_lock)) {
143 rb_erase(&user->node, &key_user_tree);
144 spin_unlock(&key_user_lock);
Serge E. Hallyn1d1e9752009-02-26 18:27:38 -0600145 put_user_ns(user->user_ns);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146
147 kfree(user);
148 }
149
150} /* end key_user_put() */
151
152/*****************************************************************************/
153/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 * assign a key the next unique serial number
Michael LeMaye51f6d32006-06-26 00:24:54 -0700155 * - these are assigned randomly to avoid security issues through covert
156 * channel problems
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 */
158static inline void key_alloc_serial(struct key *key)
159{
160 struct rb_node *parent, **p;
161 struct key *xkey;
162
Michael LeMaye51f6d32006-06-26 00:24:54 -0700163 /* propose a random serial number and look for a hole for it in the
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 * serial number tree */
Michael LeMaye51f6d32006-06-26 00:24:54 -0700165 do {
166 get_random_bytes(&key->serial, sizeof(key->serial));
167
168 key->serial >>= 1; /* negative numbers are not permitted */
169 } while (key->serial < 3);
170
171 spin_lock(&key_serial_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172
David Howells9ad08302007-02-06 13:45:51 +0000173attempt_insertion:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 parent = NULL;
175 p = &key_serial_tree.rb_node;
176
177 while (*p) {
178 parent = *p;
179 xkey = rb_entry(parent, struct key, serial_node);
180
181 if (key->serial < xkey->serial)
182 p = &(*p)->rb_left;
183 else if (key->serial > xkey->serial)
184 p = &(*p)->rb_right;
185 else
186 goto serial_exists;
187 }
David Howells9ad08302007-02-06 13:45:51 +0000188
189 /* we've found a suitable hole - arrange for this key to occupy it */
190 rb_link_node(&key->serial_node, parent, p);
191 rb_insert_color(&key->serial_node, &key_serial_tree);
192
193 spin_unlock(&key_serial_lock);
194 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195
196 /* we found a key with the proposed serial number - walk the tree from
197 * that point looking for the next unused serial number */
Michael LeMaye51f6d32006-06-26 00:24:54 -0700198serial_exists:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 for (;;) {
Michael LeMaye51f6d32006-06-26 00:24:54 -0700200 key->serial++;
David Howells9ad08302007-02-06 13:45:51 +0000201 if (key->serial < 3) {
202 key->serial = 3;
203 goto attempt_insertion;
204 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205
206 parent = rb_next(parent);
207 if (!parent)
David Howells9ad08302007-02-06 13:45:51 +0000208 goto attempt_insertion;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209
210 xkey = rb_entry(parent, struct key, serial_node);
211 if (key->serial < xkey->serial)
David Howells9ad08302007-02-06 13:45:51 +0000212 goto attempt_insertion;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 }
214
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215} /* end key_alloc_serial() */
216
217/*****************************************************************************/
218/*
219 * allocate a key of the specified type
220 * - update the user's quota to reflect the existence of the key
David Howells8d9067b2006-01-06 00:11:24 -0800221 * - called from a key-type operation with key_types_sem read-locked by
222 * key_create_or_update()
223 * - this prevents unregistration of the key type
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 * - upon return the key is as yet uninstantiated; the caller needs to either
225 * instantiate the key or discard it before returning
226 */
227struct key *key_alloc(struct key_type *type, const char *desc,
David Howellsd84f4f92008-11-14 10:39:23 +1100228 uid_t uid, gid_t gid, const struct cred *cred,
David Howells7e047ef2006-06-26 00:24:50 -0700229 key_perm_t perm, unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230{
231 struct key_user *user = NULL;
232 struct key *key;
233 size_t desclen, quotalen;
David Howells29db9192005-10-30 15:02:44 -0800234 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235
236 key = ERR_PTR(-EINVAL);
237 if (!desc || !*desc)
238 goto error;
239
240 desclen = strlen(desc) + 1;
241 quotalen = desclen + type->def_datalen;
242
243 /* get hold of the key tracking for this user */
Serge E. Hallyn1d1e9752009-02-26 18:27:38 -0600244 user = key_user_lookup(uid, cred->user->user_ns);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 if (!user)
246 goto no_memory_1;
247
248 /* check that the user's quota permits allocation of another key and
249 * its description */
David Howells7e047ef2006-06-26 00:24:50 -0700250 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
David Howells0b77f5b2008-04-29 01:01:32 -0700251 unsigned maxkeys = (uid == 0) ?
252 key_quota_root_maxkeys : key_quota_maxkeys;
253 unsigned maxbytes = (uid == 0) ?
254 key_quota_root_maxbytes : key_quota_maxbytes;
255
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 spin_lock(&user->lock);
David Howells7e047ef2006-06-26 00:24:50 -0700257 if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) {
David Howells0b77f5b2008-04-29 01:01:32 -0700258 if (user->qnkeys + 1 >= maxkeys ||
259 user->qnbytes + quotalen >= maxbytes ||
260 user->qnbytes + quotalen < user->qnbytes)
David Howells7e047ef2006-06-26 00:24:50 -0700261 goto no_quota;
262 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263
264 user->qnkeys++;
265 user->qnbytes += quotalen;
266 spin_unlock(&user->lock);
267 }
268
269 /* allocate and initialise the key and its description */
Christoph Lametere94b1762006-12-06 20:33:17 -0800270 key = kmem_cache_alloc(key_jar, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 if (!key)
272 goto no_memory_2;
273
274 if (desc) {
Eric Sesterhenn48ad5042006-12-06 20:33:47 -0800275 key->description = kmemdup(desc, desclen, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276 if (!key->description)
277 goto no_memory_3;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 }
279
280 atomic_set(&key->usage, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 init_rwsem(&key->sem);
282 key->type = type;
283 key->user = user;
284 key->quotalen = quotalen;
285 key->datalen = type->def_datalen;
286 key->uid = uid;
287 key->gid = gid;
288 key->perm = perm;
289 key->flags = 0;
290 key->expiry = 0;
291 key->payload.data = NULL;
David Howells29db9192005-10-30 15:02:44 -0800292 key->security = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293
David Howells7e047ef2006-06-26 00:24:50 -0700294 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA))
David Howells76d8aea2005-06-23 22:00:49 -0700295 key->flags |= 1 << KEY_FLAG_IN_QUOTA;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296
297 memset(&key->type_data, 0, sizeof(key->type_data));
298
299#ifdef KEY_DEBUGGING
300 key->magic = KEY_DEBUG_MAGIC;
301#endif
302
David Howells29db9192005-10-30 15:02:44 -0800303 /* let the security module know about the key */
David Howellsd84f4f92008-11-14 10:39:23 +1100304 ret = security_key_alloc(key, cred, flags);
David Howells29db9192005-10-30 15:02:44 -0800305 if (ret < 0)
306 goto security_error;
307
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 /* publish the key by giving it a serial number */
309 atomic_inc(&user->nkeys);
310 key_alloc_serial(key);
311
David Howells29db9192005-10-30 15:02:44 -0800312error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 return key;
314
David Howells29db9192005-10-30 15:02:44 -0800315security_error:
316 kfree(key->description);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317 kmem_cache_free(key_jar, key);
David Howells7e047ef2006-06-26 00:24:50 -0700318 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 spin_lock(&user->lock);
320 user->qnkeys--;
321 user->qnbytes -= quotalen;
322 spin_unlock(&user->lock);
323 }
324 key_user_put(user);
David Howells29db9192005-10-30 15:02:44 -0800325 key = ERR_PTR(ret);
326 goto error;
327
328no_memory_3:
329 kmem_cache_free(key_jar, key);
330no_memory_2:
David Howells7e047ef2006-06-26 00:24:50 -0700331 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
David Howells29db9192005-10-30 15:02:44 -0800332 spin_lock(&user->lock);
333 user->qnkeys--;
334 user->qnbytes -= quotalen;
335 spin_unlock(&user->lock);
336 }
337 key_user_put(user);
338no_memory_1:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339 key = ERR_PTR(-ENOMEM);
340 goto error;
341
David Howells29db9192005-10-30 15:02:44 -0800342no_quota:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343 spin_unlock(&user->lock);
344 key_user_put(user);
345 key = ERR_PTR(-EDQUOT);
346 goto error;
347
348} /* end key_alloc() */
349
350EXPORT_SYMBOL(key_alloc);
351
352/*****************************************************************************/
353/*
354 * reserve an amount of quota for the key's payload
355 */
356int key_payload_reserve(struct key *key, size_t datalen)
357{
358 int delta = (int) datalen - key->datalen;
359 int ret = 0;
360
361 key_check(key);
362
363 /* contemplate the quota adjustment */
David Howells76d8aea2005-06-23 22:00:49 -0700364 if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
David Howells0b77f5b2008-04-29 01:01:32 -0700365 unsigned maxbytes = (key->user->uid == 0) ?
366 key_quota_root_maxbytes : key_quota_maxbytes;
367
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 spin_lock(&key->user->lock);
369
370 if (delta > 0 &&
David Howells0b77f5b2008-04-29 01:01:32 -0700371 (key->user->qnbytes + delta >= maxbytes ||
372 key->user->qnbytes + delta < key->user->qnbytes)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 ret = -EDQUOT;
374 }
375 else {
376 key->user->qnbytes += delta;
377 key->quotalen += delta;
378 }
379 spin_unlock(&key->user->lock);
380 }
381
382 /* change the recorded data length if that didn't generate an error */
383 if (ret == 0)
384 key->datalen = datalen;
385
386 return ret;
387
388} /* end key_payload_reserve() */
389
390EXPORT_SYMBOL(key_payload_reserve);
391
392/*****************************************************************************/
393/*
394 * instantiate a key and link it into the target keyring atomically
395 * - called with the target keyring's semaphore writelocked
396 */
397static int __key_instantiate_and_link(struct key *key,
398 const void *data,
399 size_t datalen,
David Howells3e301482005-06-23 22:00:56 -0700400 struct key *keyring,
David Howellsd84f4f92008-11-14 10:39:23 +1100401 struct key *authkey)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402{
403 int ret, awaken;
404
405 key_check(key);
406 key_check(keyring);
407
408 awaken = 0;
409 ret = -EBUSY;
410
David Howells76181c12007-10-16 23:29:46 -0700411 mutex_lock(&key_construction_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412
413 /* can't instantiate twice */
David Howells76d8aea2005-06-23 22:00:49 -0700414 if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 /* instantiate the key */
416 ret = key->type->instantiate(key, data, datalen);
417
418 if (ret == 0) {
419 /* mark the key as being instantiated */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420 atomic_inc(&key->user->nikeys);
David Howells76d8aea2005-06-23 22:00:49 -0700421 set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422
David Howells76d8aea2005-06-23 22:00:49 -0700423 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 awaken = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425
426 /* and link it into the destination keyring */
427 if (keyring)
428 ret = __key_link(keyring, key);
David Howells3e301482005-06-23 22:00:56 -0700429
430 /* disable the authorisation key */
David Howellsd84f4f92008-11-14 10:39:23 +1100431 if (authkey)
432 key_revoke(authkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 }
434 }
435
David Howells76181c12007-10-16 23:29:46 -0700436 mutex_unlock(&key_construction_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437
438 /* wake up anyone waiting for a key to be constructed */
439 if (awaken)
David Howells76181c12007-10-16 23:29:46 -0700440 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441
442 return ret;
443
444} /* end __key_instantiate_and_link() */
445
446/*****************************************************************************/
447/*
448 * instantiate a key and link it into the target keyring atomically
449 */
450int key_instantiate_and_link(struct key *key,
451 const void *data,
452 size_t datalen,
David Howells3e301482005-06-23 22:00:56 -0700453 struct key *keyring,
David Howellsd84f4f92008-11-14 10:39:23 +1100454 struct key *authkey)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455{
456 int ret;
457
458 if (keyring)
459 down_write(&keyring->sem);
460
David Howellsd84f4f92008-11-14 10:39:23 +1100461 ret = __key_instantiate_and_link(key, data, datalen, keyring, authkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462
463 if (keyring)
464 up_write(&keyring->sem);
465
466 return ret;
David Howells3e301482005-06-23 22:00:56 -0700467
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468} /* end key_instantiate_and_link() */
469
470EXPORT_SYMBOL(key_instantiate_and_link);
471
472/*****************************************************************************/
473/*
474 * negatively instantiate a key and link it into the target keyring atomically
475 */
476int key_negate_and_link(struct key *key,
477 unsigned timeout,
David Howells3e301482005-06-23 22:00:56 -0700478 struct key *keyring,
David Howellsd84f4f92008-11-14 10:39:23 +1100479 struct key *authkey)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480{
481 struct timespec now;
482 int ret, awaken;
483
484 key_check(key);
485 key_check(keyring);
486
487 awaken = 0;
488 ret = -EBUSY;
489
490 if (keyring)
491 down_write(&keyring->sem);
492
David Howells76181c12007-10-16 23:29:46 -0700493 mutex_lock(&key_construction_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494
495 /* can't instantiate twice */
David Howells76d8aea2005-06-23 22:00:49 -0700496 if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497 /* mark the key as being negatively instantiated */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498 atomic_inc(&key->user->nikeys);
David Howells76d8aea2005-06-23 22:00:49 -0700499 set_bit(KEY_FLAG_NEGATIVE, &key->flags);
500 set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501 now = current_kernel_time();
502 key->expiry = now.tv_sec + timeout;
David Howellsc08ef802009-09-14 17:26:13 +0100503 key_schedule_gc(key->expiry + key_gc_delay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504
David Howells76d8aea2005-06-23 22:00:49 -0700505 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506 awaken = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 ret = 0;
509
510 /* and link it into the destination keyring */
511 if (keyring)
512 ret = __key_link(keyring, key);
David Howells3e301482005-06-23 22:00:56 -0700513
514 /* disable the authorisation key */
David Howellsd84f4f92008-11-14 10:39:23 +1100515 if (authkey)
516 key_revoke(authkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517 }
518
David Howells76181c12007-10-16 23:29:46 -0700519 mutex_unlock(&key_construction_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520
521 if (keyring)
522 up_write(&keyring->sem);
523
524 /* wake up anyone waiting for a key to be constructed */
525 if (awaken)
David Howells76181c12007-10-16 23:29:46 -0700526 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527
528 return ret;
529
530} /* end key_negate_and_link() */
531
532EXPORT_SYMBOL(key_negate_and_link);
533
534/*****************************************************************************/
535/*
536 * do cleaning up in process context so that we don't have to disable
537 * interrupts all over the place
538 */
David Howells65f27f32006-11-22 14:55:48 +0000539static void key_cleanup(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540{
541 struct rb_node *_n;
542 struct key *key;
543
544 go_again:
545 /* look for a dead key in the tree */
546 spin_lock(&key_serial_lock);
547
548 for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
549 key = rb_entry(_n, struct key, serial_node);
550
551 if (atomic_read(&key->usage) == 0)
552 goto found_dead_key;
553 }
554
555 spin_unlock(&key_serial_lock);
556 return;
557
558 found_dead_key:
559 /* we found a dead key - once we've removed it from the tree, we can
560 * drop the lock */
561 rb_erase(&key->serial_node, &key_serial_tree);
562 spin_unlock(&key_serial_lock);
563
David Howells76d8aea2005-06-23 22:00:49 -0700564 key_check(key);
565
David Howells29db9192005-10-30 15:02:44 -0800566 security_key_free(key);
567
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 /* deal with the user's key tracking and quota */
David Howells76d8aea2005-06-23 22:00:49 -0700569 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570 spin_lock(&key->user->lock);
571 key->user->qnkeys--;
572 key->user->qnbytes -= key->quotalen;
573 spin_unlock(&key->user->lock);
574 }
575
576 atomic_dec(&key->user->nkeys);
David Howells76d8aea2005-06-23 22:00:49 -0700577 if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578 atomic_dec(&key->user->nikeys);
579
580 key_user_put(key->user);
581
582 /* now throw away the key memory */
583 if (key->type->destroy)
584 key->type->destroy(key);
585
586 kfree(key->description);
587
588#ifdef KEY_DEBUGGING
589 key->magic = KEY_DEBUG_MAGIC_X;
590#endif
591 kmem_cache_free(key_jar, key);
592
593 /* there may, of course, be more than one key to destroy */
594 goto go_again;
595
596} /* end key_cleanup() */
597
598/*****************************************************************************/
599/*
600 * dispose of a reference to a key
601 * - when all the references are gone, we schedule the cleanup task to come and
602 * pull it out of the tree in definite process context
603 */
604void key_put(struct key *key)
605{
606 if (key) {
607 key_check(key);
608
609 if (atomic_dec_and_test(&key->usage))
610 schedule_work(&key_cleanup_task);
611 }
612
613} /* end key_put() */
614
615EXPORT_SYMBOL(key_put);
616
617/*****************************************************************************/
618/*
619 * find a key by its serial number
620 */
621struct key *key_lookup(key_serial_t id)
622{
623 struct rb_node *n;
624 struct key *key;
625
626 spin_lock(&key_serial_lock);
627
628 /* search the tree for the specified key */
629 n = key_serial_tree.rb_node;
630 while (n) {
631 key = rb_entry(n, struct key, serial_node);
632
633 if (id < key->serial)
634 n = n->rb_left;
635 else if (id > key->serial)
636 n = n->rb_right;
637 else
638 goto found;
639 }
640
641 not_found:
642 key = ERR_PTR(-ENOKEY);
643 goto error;
644
645 found:
David Howells55931222009-09-02 09:13:45 +0100646 /* pretend it doesn't exist if it is awaiting deletion */
647 if (atomic_read(&key->usage) == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 goto not_found;
649
650 /* this races with key_put(), but that doesn't matter since key_put()
651 * doesn't actually change the key
652 */
653 atomic_inc(&key->usage);
654
655 error:
656 spin_unlock(&key_serial_lock);
657 return key;
658
659} /* end key_lookup() */
660
661/*****************************************************************************/
662/*
663 * find and lock the specified key type against removal
664 * - we return with the sem readlocked
665 */
666struct key_type *key_type_lookup(const char *type)
667{
668 struct key_type *ktype;
669
670 down_read(&key_types_sem);
671
672 /* look up the key type to see if it's one of the registered kernel
673 * types */
674 list_for_each_entry(ktype, &key_types_list, link) {
675 if (strcmp(ktype->name, type) == 0)
676 goto found_kernel_type;
677 }
678
679 up_read(&key_types_sem);
680 ktype = ERR_PTR(-ENOKEY);
681
682 found_kernel_type:
683 return ktype;
684
685} /* end key_type_lookup() */
686
687/*****************************************************************************/
688/*
689 * unlock a key type
690 */
691void key_type_put(struct key_type *ktype)
692{
693 up_read(&key_types_sem);
694
695} /* end key_type_put() */
696
697/*****************************************************************************/
698/*
699 * attempt to update an existing key
700 * - the key has an incremented refcount
701 * - we need to put the key if we get an error
702 */
David Howells664cceb2005-09-28 17:03:15 +0100703static inline key_ref_t __key_update(key_ref_t key_ref,
704 const void *payload, size_t plen)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705{
David Howells664cceb2005-09-28 17:03:15 +0100706 struct key *key = key_ref_to_ptr(key_ref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 int ret;
708
709 /* need write permission on the key to update it */
David Howells29db9192005-10-30 15:02:44 -0800710 ret = key_permission(key_ref, KEY_WRITE);
711 if (ret < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712 goto error;
713
714 ret = -EEXIST;
715 if (!key->type->update)
716 goto error;
717
718 down_write(&key->sem);
719
720 ret = key->type->update(key, payload, plen);
David Howells76d8aea2005-06-23 22:00:49 -0700721 if (ret == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722 /* updating a negative key instantiates it */
David Howells76d8aea2005-06-23 22:00:49 -0700723 clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724
725 up_write(&key->sem);
726
727 if (ret < 0)
728 goto error;
David Howells664cceb2005-09-28 17:03:15 +0100729out:
730 return key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731
David Howells664cceb2005-09-28 17:03:15 +0100732error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733 key_put(key);
David Howells664cceb2005-09-28 17:03:15 +0100734 key_ref = ERR_PTR(ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 goto out;
736
737} /* end __key_update() */
738
739/*****************************************************************************/
740/*
741 * search the specified keyring for a key of the same description; if one is
742 * found, update it, otherwise add a new one
743 */
David Howells664cceb2005-09-28 17:03:15 +0100744key_ref_t key_create_or_update(key_ref_t keyring_ref,
745 const char *type,
746 const char *description,
747 const void *payload,
748 size_t plen,
Arun Raghavan6b79ccb2008-04-29 01:01:28 -0700749 key_perm_t perm,
David Howells7e047ef2006-06-26 00:24:50 -0700750 unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751{
David Howellsd84f4f92008-11-14 10:39:23 +1100752 const struct cred *cred = current_cred();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 struct key_type *ktype;
David Howells664cceb2005-09-28 17:03:15 +0100754 struct key *keyring, *key = NULL;
David Howells664cceb2005-09-28 17:03:15 +0100755 key_ref_t key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700756 int ret;
757
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758 /* look up the key type to see if it's one of the registered kernel
759 * types */
760 ktype = key_type_lookup(type);
761 if (IS_ERR(ktype)) {
David Howells664cceb2005-09-28 17:03:15 +0100762 key_ref = ERR_PTR(-ENODEV);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763 goto error;
764 }
765
David Howells664cceb2005-09-28 17:03:15 +0100766 key_ref = ERR_PTR(-EINVAL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767 if (!ktype->match || !ktype->instantiate)
768 goto error_2;
769
David Howells664cceb2005-09-28 17:03:15 +0100770 keyring = key_ref_to_ptr(keyring_ref);
771
772 key_check(keyring);
773
David Howellsc3a9d652006-04-10 15:15:21 +0100774 key_ref = ERR_PTR(-ENOTDIR);
775 if (keyring->type != &key_type_keyring)
776 goto error_2;
777
David Howells664cceb2005-09-28 17:03:15 +0100778 down_write(&keyring->sem);
779
780 /* if we're going to allocate a new key, we're going to have
781 * to modify the keyring */
David Howells29db9192005-10-30 15:02:44 -0800782 ret = key_permission(keyring_ref, KEY_WRITE);
783 if (ret < 0) {
784 key_ref = ERR_PTR(ret);
David Howells664cceb2005-09-28 17:03:15 +0100785 goto error_3;
David Howells29db9192005-10-30 15:02:44 -0800786 }
David Howells664cceb2005-09-28 17:03:15 +0100787
David Howells1d9b7d92006-03-25 03:06:52 -0800788 /* if it's possible to update this type of key, search for an existing
789 * key of the same type and description in the destination keyring and
790 * update that instead if possible
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791 */
David Howells1d9b7d92006-03-25 03:06:52 -0800792 if (ktype->update) {
793 key_ref = __keyring_search_one(keyring_ref, ktype, description,
794 0);
795 if (!IS_ERR(key_ref))
796 goto found_matching_key;
797 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798
Arun Raghavan6b79ccb2008-04-29 01:01:28 -0700799 /* if the client doesn't provide, decide on the permissions we want */
800 if (perm == KEY_PERM_UNDEF) {
801 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
802 perm |= KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK | KEY_USR_SETATTR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803
Arun Raghavan6b79ccb2008-04-29 01:01:28 -0700804 if (ktype->read)
805 perm |= KEY_POS_READ | KEY_USR_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806
Arun Raghavan6b79ccb2008-04-29 01:01:28 -0700807 if (ktype == &key_type_keyring || ktype->update)
808 perm |= KEY_USR_WRITE;
809 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810
811 /* allocate a new key */
David Howellsd84f4f92008-11-14 10:39:23 +1100812 key = key_alloc(ktype, description, cred->fsuid, cred->fsgid, cred,
813 perm, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814 if (IS_ERR(key)) {
David Howellse231c2e2008-02-07 00:15:26 -0800815 key_ref = ERR_CAST(key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816 goto error_3;
817 }
818
819 /* instantiate it and link it into the target keyring */
David Howells3e301482005-06-23 22:00:56 -0700820 ret = __key_instantiate_and_link(key, payload, plen, keyring, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821 if (ret < 0) {
822 key_put(key);
David Howells664cceb2005-09-28 17:03:15 +0100823 key_ref = ERR_PTR(ret);
824 goto error_3;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825 }
826
David Howells664cceb2005-09-28 17:03:15 +0100827 key_ref = make_key_ref(key, is_key_possessed(keyring_ref));
828
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829 error_3:
830 up_write(&keyring->sem);
831 error_2:
832 key_type_put(ktype);
833 error:
David Howells664cceb2005-09-28 17:03:15 +0100834 return key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700835
836 found_matching_key:
837 /* we found a matching key, so we're going to try to update it
838 * - we can drop the locks first as we have the key pinned
839 */
840 up_write(&keyring->sem);
841 key_type_put(ktype);
842
David Howells664cceb2005-09-28 17:03:15 +0100843 key_ref = __key_update(key_ref, payload, plen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844 goto error;
845
846} /* end key_create_or_update() */
847
848EXPORT_SYMBOL(key_create_or_update);
849
850/*****************************************************************************/
851/*
852 * update a key
853 */
David Howells664cceb2005-09-28 17:03:15 +0100854int key_update(key_ref_t key_ref, const void *payload, size_t plen)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855{
David Howells664cceb2005-09-28 17:03:15 +0100856 struct key *key = key_ref_to_ptr(key_ref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857 int ret;
858
859 key_check(key);
860
861 /* the key must be writable */
David Howells29db9192005-10-30 15:02:44 -0800862 ret = key_permission(key_ref, KEY_WRITE);
863 if (ret < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864 goto error;
865
866 /* attempt to update it if supported */
867 ret = -EOPNOTSUPP;
868 if (key->type->update) {
869 down_write(&key->sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870
David Howells29db9192005-10-30 15:02:44 -0800871 ret = key->type->update(key, payload, plen);
David Howells76d8aea2005-06-23 22:00:49 -0700872 if (ret == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873 /* updating a negative key instantiates it */
David Howells76d8aea2005-06-23 22:00:49 -0700874 clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875
876 up_write(&key->sem);
877 }
878
879 error:
880 return ret;
881
882} /* end key_update() */
883
884EXPORT_SYMBOL(key_update);
885
886/*****************************************************************************/
887/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700888 * revoke a key
889 */
890void key_revoke(struct key *key)
891{
David Howells5d135442009-09-02 09:14:00 +0100892 struct timespec now;
893 time_t time;
894
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895 key_check(key);
896
David Howells76181c12007-10-16 23:29:46 -0700897 /* make sure no one's trying to change or use the key when we mark it
898 * - we tell lockdep that we might nest because we might be revoking an
899 * authorisation key whilst holding the sem on a key we've just
900 * instantiated
901 */
902 down_write_nested(&key->sem, 1);
903 if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags) &&
904 key->type->revoke)
David Howells04c567d2006-06-22 14:47:18 -0700905 key->type->revoke(key);
906
David Howells5d135442009-09-02 09:14:00 +0100907 /* set the death time to no more than the expiry time */
908 now = current_kernel_time();
909 time = now.tv_sec;
910 if (key->revoked_at == 0 || key->revoked_at > time) {
911 key->revoked_at = time;
David Howellsc08ef802009-09-14 17:26:13 +0100912 key_schedule_gc(key->revoked_at + key_gc_delay);
David Howells5d135442009-09-02 09:14:00 +0100913 }
914
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915 up_write(&key->sem);
916
917} /* end key_revoke() */
918
919EXPORT_SYMBOL(key_revoke);
920
921/*****************************************************************************/
922/*
923 * register a type of key
924 */
925int register_key_type(struct key_type *ktype)
926{
927 struct key_type *p;
928 int ret;
929
930 ret = -EEXIST;
931 down_write(&key_types_sem);
932
933 /* disallow key types with the same name */
934 list_for_each_entry(p, &key_types_list, link) {
935 if (strcmp(p->name, ktype->name) == 0)
936 goto out;
937 }
938
939 /* store the type */
940 list_add(&ktype->link, &key_types_list);
941 ret = 0;
942
943 out:
944 up_write(&key_types_sem);
945 return ret;
946
947} /* end register_key_type() */
948
949EXPORT_SYMBOL(register_key_type);
950
951/*****************************************************************************/
952/*
953 * unregister a type of key
954 */
955void unregister_key_type(struct key_type *ktype)
956{
957 struct rb_node *_n;
958 struct key *key;
959
960 down_write(&key_types_sem);
961
962 /* withdraw the key type */
963 list_del_init(&ktype->link);
964
David Howells76d8aea2005-06-23 22:00:49 -0700965 /* mark all the keys of this type dead */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700966 spin_lock(&key_serial_lock);
967
968 for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
969 key = rb_entry(_n, struct key, serial_node);
970
David Howellsf041ae22009-09-02 09:13:55 +0100971 if (key->type == ktype) {
David Howells76d8aea2005-06-23 22:00:49 -0700972 key->type = &key_type_dead;
David Howellsf041ae22009-09-02 09:13:55 +0100973 set_bit(KEY_FLAG_DEAD, &key->flags);
974 }
David Howells76d8aea2005-06-23 22:00:49 -0700975 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976
David Howells76d8aea2005-06-23 22:00:49 -0700977 spin_unlock(&key_serial_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700978
David Howells76d8aea2005-06-23 22:00:49 -0700979 /* make sure everyone revalidates their keys */
Paul E. McKenneyb2b18662005-06-25 14:55:38 -0700980 synchronize_rcu();
David Howells76d8aea2005-06-23 22:00:49 -0700981
982 /* we should now be able to destroy the payloads of all the keys of
983 * this type with impunity */
984 spin_lock(&key_serial_lock);
985
986 for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
987 key = rb_entry(_n, struct key, serial_node);
988
989 if (key->type == ktype) {
990 if (ktype->destroy)
991 ktype->destroy(key);
Randy Dunlapa7807a32006-06-27 02:53:54 -0700992 memset(&key->payload, KEY_DESTROY, sizeof(key->payload));
David Howells76d8aea2005-06-23 22:00:49 -0700993 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994 }
995
996 spin_unlock(&key_serial_lock);
997 up_write(&key_types_sem);
998
David Howells5d135442009-09-02 09:14:00 +0100999 key_schedule_gc(0);
1000
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001} /* end unregister_key_type() */
1002
1003EXPORT_SYMBOL(unregister_key_type);
1004
1005/*****************************************************************************/
1006/*
1007 * initialise the key management stuff
1008 */
1009void __init key_init(void)
1010{
1011 /* allocate a slab in which we can store keys */
1012 key_jar = kmem_cache_create("key_jar", sizeof(struct key),
Paul Mundt20c2df82007-07-20 10:11:58 +09001013 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014
1015 /* add the special key types */
1016 list_add_tail(&key_type_keyring.link, &key_types_list);
1017 list_add_tail(&key_type_dead.link, &key_types_list);
1018 list_add_tail(&key_type_user.link, &key_types_list);
1019
1020 /* record the root user tracking */
1021 rb_link_node(&root_key_user.node,
1022 NULL,
1023 &key_user_tree.rb_node);
1024
1025 rb_insert_color(&root_key_user.node,
1026 &key_user_tree);
1027
Linus Torvalds1da177e2005-04-16 15:20:36 -07001028} /* end key_init() */