blob: f76c8a546fd3688e4cc2cadd076e05debe43f9a3 [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>
21#include "internal.h"
22
Christoph Lametere18b8902006-12-06 20:33:20 -080023static struct kmem_cache *key_jar;
Linus Torvalds1da177e2005-04-16 15:20:36 -070024struct rb_root key_serial_tree; /* tree of keys indexed by serial */
25DEFINE_SPINLOCK(key_serial_lock);
26
27struct rb_root key_user_tree; /* tree of quota records indexed by UID */
28DEFINE_SPINLOCK(key_user_lock);
29
David Howells0b77f5b2008-04-29 01:01:32 -070030unsigned int key_quota_root_maxkeys = 200; /* root's key count quota */
31unsigned int key_quota_root_maxbytes = 20000; /* root's key space quota */
32unsigned int key_quota_maxkeys = 200; /* general key count quota */
33unsigned int key_quota_maxbytes = 20000; /* general key space quota */
34
Linus Torvalds1da177e2005-04-16 15:20:36 -070035static LIST_HEAD(key_types_list);
36static DECLARE_RWSEM(key_types_sem);
37
David Howells65f27f32006-11-22 14:55:48 +000038static void key_cleanup(struct work_struct *work);
39static DECLARE_WORK(key_cleanup_task, key_cleanup);
Linus Torvalds1da177e2005-04-16 15:20:36 -070040
41/* we serialise key instantiation and link */
David Howells76181c12007-10-16 23:29:46 -070042DEFINE_MUTEX(key_construction_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070043
44/* any key who's type gets unegistered will be re-typed to this */
Adrian Bunk1ae8f402006-01-06 00:11:25 -080045static struct key_type key_type_dead = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 .name = "dead",
47};
48
49#ifdef KEY_DEBUGGING
50void __key_check(const struct key *key)
51{
52 printk("__key_check: key %p {%08x} should be {%08x}\n",
53 key, key->magic, KEY_DEBUG_MAGIC);
54 BUG();
55}
56#endif
57
58/*****************************************************************************/
59/*
60 * get the key quota record for a user, allocating a new record if one doesn't
61 * already exist
62 */
63struct key_user *key_user_lookup(uid_t uid)
64{
65 struct key_user *candidate = NULL, *user;
66 struct rb_node *parent = NULL;
67 struct rb_node **p;
68
69 try_again:
70 p = &key_user_tree.rb_node;
71 spin_lock(&key_user_lock);
72
73 /* search the tree for a user record with a matching UID */
74 while (*p) {
75 parent = *p;
76 user = rb_entry(parent, struct key_user, node);
77
78 if (uid < user->uid)
79 p = &(*p)->rb_left;
80 else if (uid > user->uid)
81 p = &(*p)->rb_right;
82 else
83 goto found;
84 }
85
86 /* if we get here, we failed to find a match in the tree */
87 if (!candidate) {
88 /* allocate a candidate user record if we don't already have
89 * one */
90 spin_unlock(&key_user_lock);
91
92 user = NULL;
93 candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL);
94 if (unlikely(!candidate))
95 goto out;
96
97 /* the allocation may have scheduled, so we need to repeat the
98 * search lest someone else added the record whilst we were
99 * asleep */
100 goto try_again;
101 }
102
103 /* if we get here, then the user record still hadn't appeared on the
104 * second pass - so we use the candidate record */
105 atomic_set(&candidate->usage, 1);
106 atomic_set(&candidate->nkeys, 0);
107 atomic_set(&candidate->nikeys, 0);
108 candidate->uid = uid;
109 candidate->qnkeys = 0;
110 candidate->qnbytes = 0;
111 spin_lock_init(&candidate->lock);
David Howells76181c12007-10-16 23:29:46 -0700112 mutex_init(&candidate->cons_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113
114 rb_link_node(&candidate->node, parent, p);
115 rb_insert_color(&candidate->node, &key_user_tree);
116 spin_unlock(&key_user_lock);
117 user = candidate;
118 goto out;
119
120 /* okay - we found a user record for this UID */
121 found:
122 atomic_inc(&user->usage);
123 spin_unlock(&key_user_lock);
Jesper Juhla7f988b2005-11-07 01:01:35 -0800124 kfree(candidate);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 out:
126 return user;
127
128} /* end key_user_lookup() */
129
130/*****************************************************************************/
131/*
132 * dispose of a user structure
133 */
134void key_user_put(struct key_user *user)
135{
136 if (atomic_dec_and_lock(&user->usage, &key_user_lock)) {
137 rb_erase(&user->node, &key_user_tree);
138 spin_unlock(&key_user_lock);
139
140 kfree(user);
141 }
142
143} /* end key_user_put() */
144
145/*****************************************************************************/
146/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 * assign a key the next unique serial number
Michael LeMaye51f6d32006-06-26 00:24:54 -0700148 * - these are assigned randomly to avoid security issues through covert
149 * channel problems
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 */
151static inline void key_alloc_serial(struct key *key)
152{
153 struct rb_node *parent, **p;
154 struct key *xkey;
155
Michael LeMaye51f6d32006-06-26 00:24:54 -0700156 /* propose a random serial number and look for a hole for it in the
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 * serial number tree */
Michael LeMaye51f6d32006-06-26 00:24:54 -0700158 do {
159 get_random_bytes(&key->serial, sizeof(key->serial));
160
161 key->serial >>= 1; /* negative numbers are not permitted */
162 } while (key->serial < 3);
163
164 spin_lock(&key_serial_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165
David Howells9ad08302007-02-06 13:45:51 +0000166attempt_insertion:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 parent = NULL;
168 p = &key_serial_tree.rb_node;
169
170 while (*p) {
171 parent = *p;
172 xkey = rb_entry(parent, struct key, serial_node);
173
174 if (key->serial < xkey->serial)
175 p = &(*p)->rb_left;
176 else if (key->serial > xkey->serial)
177 p = &(*p)->rb_right;
178 else
179 goto serial_exists;
180 }
David Howells9ad08302007-02-06 13:45:51 +0000181
182 /* we've found a suitable hole - arrange for this key to occupy it */
183 rb_link_node(&key->serial_node, parent, p);
184 rb_insert_color(&key->serial_node, &key_serial_tree);
185
186 spin_unlock(&key_serial_lock);
187 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188
189 /* we found a key with the proposed serial number - walk the tree from
190 * that point looking for the next unused serial number */
Michael LeMaye51f6d32006-06-26 00:24:54 -0700191serial_exists:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 for (;;) {
Michael LeMaye51f6d32006-06-26 00:24:54 -0700193 key->serial++;
David Howells9ad08302007-02-06 13:45:51 +0000194 if (key->serial < 3) {
195 key->serial = 3;
196 goto attempt_insertion;
197 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198
199 parent = rb_next(parent);
200 if (!parent)
David Howells9ad08302007-02-06 13:45:51 +0000201 goto attempt_insertion;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202
203 xkey = rb_entry(parent, struct key, serial_node);
204 if (key->serial < xkey->serial)
David Howells9ad08302007-02-06 13:45:51 +0000205 goto attempt_insertion;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 }
207
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208} /* end key_alloc_serial() */
209
210/*****************************************************************************/
211/*
212 * allocate a key of the specified type
213 * - update the user's quota to reflect the existence of the key
David Howells8d9067b2006-01-06 00:11:24 -0800214 * - called from a key-type operation with key_types_sem read-locked by
215 * key_create_or_update()
216 * - this prevents unregistration of the key type
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 * - upon return the key is as yet uninstantiated; the caller needs to either
218 * instantiate the key or discard it before returning
219 */
220struct key *key_alloc(struct key_type *type, const char *desc,
David Howellsd84f4f92008-11-14 10:39:23 +1100221 uid_t uid, gid_t gid, const struct cred *cred,
David Howells7e047ef2006-06-26 00:24:50 -0700222 key_perm_t perm, unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223{
224 struct key_user *user = NULL;
225 struct key *key;
226 size_t desclen, quotalen;
David Howells29db9192005-10-30 15:02:44 -0800227 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228
229 key = ERR_PTR(-EINVAL);
230 if (!desc || !*desc)
231 goto error;
232
233 desclen = strlen(desc) + 1;
234 quotalen = desclen + type->def_datalen;
235
236 /* get hold of the key tracking for this user */
237 user = key_user_lookup(uid);
238 if (!user)
239 goto no_memory_1;
240
241 /* check that the user's quota permits allocation of another key and
242 * its description */
David Howells7e047ef2006-06-26 00:24:50 -0700243 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
David Howells0b77f5b2008-04-29 01:01:32 -0700244 unsigned maxkeys = (uid == 0) ?
245 key_quota_root_maxkeys : key_quota_maxkeys;
246 unsigned maxbytes = (uid == 0) ?
247 key_quota_root_maxbytes : key_quota_maxbytes;
248
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 spin_lock(&user->lock);
David Howells7e047ef2006-06-26 00:24:50 -0700250 if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) {
David Howells0b77f5b2008-04-29 01:01:32 -0700251 if (user->qnkeys + 1 >= maxkeys ||
252 user->qnbytes + quotalen >= maxbytes ||
253 user->qnbytes + quotalen < user->qnbytes)
David Howells7e047ef2006-06-26 00:24:50 -0700254 goto no_quota;
255 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256
257 user->qnkeys++;
258 user->qnbytes += quotalen;
259 spin_unlock(&user->lock);
260 }
261
262 /* allocate and initialise the key and its description */
Christoph Lametere94b1762006-12-06 20:33:17 -0800263 key = kmem_cache_alloc(key_jar, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264 if (!key)
265 goto no_memory_2;
266
267 if (desc) {
Eric Sesterhenn48ad5042006-12-06 20:33:47 -0800268 key->description = kmemdup(desc, desclen, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 if (!key->description)
270 goto no_memory_3;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 }
272
273 atomic_set(&key->usage, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 init_rwsem(&key->sem);
275 key->type = type;
276 key->user = user;
277 key->quotalen = quotalen;
278 key->datalen = type->def_datalen;
279 key->uid = uid;
280 key->gid = gid;
281 key->perm = perm;
282 key->flags = 0;
283 key->expiry = 0;
284 key->payload.data = NULL;
David Howells29db9192005-10-30 15:02:44 -0800285 key->security = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286
David Howells7e047ef2006-06-26 00:24:50 -0700287 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA))
David Howells76d8aea2005-06-23 22:00:49 -0700288 key->flags |= 1 << KEY_FLAG_IN_QUOTA;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289
290 memset(&key->type_data, 0, sizeof(key->type_data));
291
292#ifdef KEY_DEBUGGING
293 key->magic = KEY_DEBUG_MAGIC;
294#endif
295
David Howells29db9192005-10-30 15:02:44 -0800296 /* let the security module know about the key */
David Howellsd84f4f92008-11-14 10:39:23 +1100297 ret = security_key_alloc(key, cred, flags);
David Howells29db9192005-10-30 15:02:44 -0800298 if (ret < 0)
299 goto security_error;
300
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 /* publish the key by giving it a serial number */
302 atomic_inc(&user->nkeys);
303 key_alloc_serial(key);
304
David Howells29db9192005-10-30 15:02:44 -0800305error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306 return key;
307
David Howells29db9192005-10-30 15:02:44 -0800308security_error:
309 kfree(key->description);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 kmem_cache_free(key_jar, key);
David Howells7e047ef2006-06-26 00:24:50 -0700311 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312 spin_lock(&user->lock);
313 user->qnkeys--;
314 user->qnbytes -= quotalen;
315 spin_unlock(&user->lock);
316 }
317 key_user_put(user);
David Howells29db9192005-10-30 15:02:44 -0800318 key = ERR_PTR(ret);
319 goto error;
320
321no_memory_3:
322 kmem_cache_free(key_jar, key);
323no_memory_2:
David Howells7e047ef2006-06-26 00:24:50 -0700324 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
David Howells29db9192005-10-30 15:02:44 -0800325 spin_lock(&user->lock);
326 user->qnkeys--;
327 user->qnbytes -= quotalen;
328 spin_unlock(&user->lock);
329 }
330 key_user_put(user);
331no_memory_1:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332 key = ERR_PTR(-ENOMEM);
333 goto error;
334
David Howells29db9192005-10-30 15:02:44 -0800335no_quota:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 spin_unlock(&user->lock);
337 key_user_put(user);
338 key = ERR_PTR(-EDQUOT);
339 goto error;
340
341} /* end key_alloc() */
342
343EXPORT_SYMBOL(key_alloc);
344
345/*****************************************************************************/
346/*
347 * reserve an amount of quota for the key's payload
348 */
349int key_payload_reserve(struct key *key, size_t datalen)
350{
351 int delta = (int) datalen - key->datalen;
352 int ret = 0;
353
354 key_check(key);
355
356 /* contemplate the quota adjustment */
David Howells76d8aea2005-06-23 22:00:49 -0700357 if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
David Howells0b77f5b2008-04-29 01:01:32 -0700358 unsigned maxbytes = (key->user->uid == 0) ?
359 key_quota_root_maxbytes : key_quota_maxbytes;
360
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 spin_lock(&key->user->lock);
362
363 if (delta > 0 &&
David Howells0b77f5b2008-04-29 01:01:32 -0700364 (key->user->qnbytes + delta >= maxbytes ||
365 key->user->qnbytes + delta < key->user->qnbytes)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 ret = -EDQUOT;
367 }
368 else {
369 key->user->qnbytes += delta;
370 key->quotalen += delta;
371 }
372 spin_unlock(&key->user->lock);
373 }
374
375 /* change the recorded data length if that didn't generate an error */
376 if (ret == 0)
377 key->datalen = datalen;
378
379 return ret;
380
381} /* end key_payload_reserve() */
382
383EXPORT_SYMBOL(key_payload_reserve);
384
385/*****************************************************************************/
386/*
387 * instantiate a key and link it into the target keyring atomically
388 * - called with the target keyring's semaphore writelocked
389 */
390static int __key_instantiate_and_link(struct key *key,
391 const void *data,
392 size_t datalen,
David Howells3e301482005-06-23 22:00:56 -0700393 struct key *keyring,
David Howellsd84f4f92008-11-14 10:39:23 +1100394 struct key *authkey)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395{
396 int ret, awaken;
397
398 key_check(key);
399 key_check(keyring);
400
401 awaken = 0;
402 ret = -EBUSY;
403
David Howells76181c12007-10-16 23:29:46 -0700404 mutex_lock(&key_construction_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405
406 /* can't instantiate twice */
David Howells76d8aea2005-06-23 22:00:49 -0700407 if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408 /* instantiate the key */
409 ret = key->type->instantiate(key, data, datalen);
410
411 if (ret == 0) {
412 /* mark the key as being instantiated */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 atomic_inc(&key->user->nikeys);
David Howells76d8aea2005-06-23 22:00:49 -0700414 set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415
David Howells76d8aea2005-06-23 22:00:49 -0700416 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417 awaken = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418
419 /* and link it into the destination keyring */
420 if (keyring)
421 ret = __key_link(keyring, key);
David Howells3e301482005-06-23 22:00:56 -0700422
423 /* disable the authorisation key */
David Howellsd84f4f92008-11-14 10:39:23 +1100424 if (authkey)
425 key_revoke(authkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 }
427 }
428
David Howells76181c12007-10-16 23:29:46 -0700429 mutex_unlock(&key_construction_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430
431 /* wake up anyone waiting for a key to be constructed */
432 if (awaken)
David Howells76181c12007-10-16 23:29:46 -0700433 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434
435 return ret;
436
437} /* end __key_instantiate_and_link() */
438
439/*****************************************************************************/
440/*
441 * instantiate a key and link it into the target keyring atomically
442 */
443int key_instantiate_and_link(struct key *key,
444 const void *data,
445 size_t datalen,
David Howells3e301482005-06-23 22:00:56 -0700446 struct key *keyring,
David Howellsd84f4f92008-11-14 10:39:23 +1100447 struct key *authkey)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448{
449 int ret;
450
451 if (keyring)
452 down_write(&keyring->sem);
453
David Howellsd84f4f92008-11-14 10:39:23 +1100454 ret = __key_instantiate_and_link(key, data, datalen, keyring, authkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455
456 if (keyring)
457 up_write(&keyring->sem);
458
459 return ret;
David Howells3e301482005-06-23 22:00:56 -0700460
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461} /* end key_instantiate_and_link() */
462
463EXPORT_SYMBOL(key_instantiate_and_link);
464
465/*****************************************************************************/
466/*
467 * negatively instantiate a key and link it into the target keyring atomically
468 */
469int key_negate_and_link(struct key *key,
470 unsigned timeout,
David Howells3e301482005-06-23 22:00:56 -0700471 struct key *keyring,
David Howellsd84f4f92008-11-14 10:39:23 +1100472 struct key *authkey)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473{
474 struct timespec now;
475 int ret, awaken;
476
477 key_check(key);
478 key_check(keyring);
479
480 awaken = 0;
481 ret = -EBUSY;
482
483 if (keyring)
484 down_write(&keyring->sem);
485
David Howells76181c12007-10-16 23:29:46 -0700486 mutex_lock(&key_construction_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487
488 /* can't instantiate twice */
David Howells76d8aea2005-06-23 22:00:49 -0700489 if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 /* mark the key as being negatively instantiated */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 atomic_inc(&key->user->nikeys);
David Howells76d8aea2005-06-23 22:00:49 -0700492 set_bit(KEY_FLAG_NEGATIVE, &key->flags);
493 set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494 now = current_kernel_time();
495 key->expiry = now.tv_sec + timeout;
496
David Howells76d8aea2005-06-23 22:00:49 -0700497 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498 awaken = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500 ret = 0;
501
502 /* and link it into the destination keyring */
503 if (keyring)
504 ret = __key_link(keyring, key);
David Howells3e301482005-06-23 22:00:56 -0700505
506 /* disable the authorisation key */
David Howellsd84f4f92008-11-14 10:39:23 +1100507 if (authkey)
508 key_revoke(authkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509 }
510
David Howells76181c12007-10-16 23:29:46 -0700511 mutex_unlock(&key_construction_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512
513 if (keyring)
514 up_write(&keyring->sem);
515
516 /* wake up anyone waiting for a key to be constructed */
517 if (awaken)
David Howells76181c12007-10-16 23:29:46 -0700518 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519
520 return ret;
521
522} /* end key_negate_and_link() */
523
524EXPORT_SYMBOL(key_negate_and_link);
525
526/*****************************************************************************/
527/*
528 * do cleaning up in process context so that we don't have to disable
529 * interrupts all over the place
530 */
David Howells65f27f32006-11-22 14:55:48 +0000531static void key_cleanup(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532{
533 struct rb_node *_n;
534 struct key *key;
535
536 go_again:
537 /* look for a dead key in the tree */
538 spin_lock(&key_serial_lock);
539
540 for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
541 key = rb_entry(_n, struct key, serial_node);
542
543 if (atomic_read(&key->usage) == 0)
544 goto found_dead_key;
545 }
546
547 spin_unlock(&key_serial_lock);
548 return;
549
550 found_dead_key:
551 /* we found a dead key - once we've removed it from the tree, we can
552 * drop the lock */
553 rb_erase(&key->serial_node, &key_serial_tree);
554 spin_unlock(&key_serial_lock);
555
David Howells76d8aea2005-06-23 22:00:49 -0700556 key_check(key);
557
David Howells29db9192005-10-30 15:02:44 -0800558 security_key_free(key);
559
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 /* deal with the user's key tracking and quota */
David Howells76d8aea2005-06-23 22:00:49 -0700561 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 spin_lock(&key->user->lock);
563 key->user->qnkeys--;
564 key->user->qnbytes -= key->quotalen;
565 spin_unlock(&key->user->lock);
566 }
567
568 atomic_dec(&key->user->nkeys);
David Howells76d8aea2005-06-23 22:00:49 -0700569 if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570 atomic_dec(&key->user->nikeys);
571
572 key_user_put(key->user);
573
574 /* now throw away the key memory */
575 if (key->type->destroy)
576 key->type->destroy(key);
577
578 kfree(key->description);
579
580#ifdef KEY_DEBUGGING
581 key->magic = KEY_DEBUG_MAGIC_X;
582#endif
583 kmem_cache_free(key_jar, key);
584
585 /* there may, of course, be more than one key to destroy */
586 goto go_again;
587
588} /* end key_cleanup() */
589
590/*****************************************************************************/
591/*
592 * dispose of a reference to a key
593 * - when all the references are gone, we schedule the cleanup task to come and
594 * pull it out of the tree in definite process context
595 */
596void key_put(struct key *key)
597{
598 if (key) {
599 key_check(key);
600
601 if (atomic_dec_and_test(&key->usage))
602 schedule_work(&key_cleanup_task);
603 }
604
605} /* end key_put() */
606
607EXPORT_SYMBOL(key_put);
608
609/*****************************************************************************/
610/*
611 * find a key by its serial number
612 */
613struct key *key_lookup(key_serial_t id)
614{
615 struct rb_node *n;
616 struct key *key;
617
618 spin_lock(&key_serial_lock);
619
620 /* search the tree for the specified key */
621 n = key_serial_tree.rb_node;
622 while (n) {
623 key = rb_entry(n, struct key, serial_node);
624
625 if (id < key->serial)
626 n = n->rb_left;
627 else if (id > key->serial)
628 n = n->rb_right;
629 else
630 goto found;
631 }
632
633 not_found:
634 key = ERR_PTR(-ENOKEY);
635 goto error;
636
637 found:
David Howells76d8aea2005-06-23 22:00:49 -0700638 /* pretend it doesn't exist if it's dead */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700639 if (atomic_read(&key->usage) == 0 ||
David Howells76d8aea2005-06-23 22:00:49 -0700640 test_bit(KEY_FLAG_DEAD, &key->flags) ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 key->type == &key_type_dead)
642 goto not_found;
643
644 /* this races with key_put(), but that doesn't matter since key_put()
645 * doesn't actually change the key
646 */
647 atomic_inc(&key->usage);
648
649 error:
650 spin_unlock(&key_serial_lock);
651 return key;
652
653} /* end key_lookup() */
654
655/*****************************************************************************/
656/*
657 * find and lock the specified key type against removal
658 * - we return with the sem readlocked
659 */
660struct key_type *key_type_lookup(const char *type)
661{
662 struct key_type *ktype;
663
664 down_read(&key_types_sem);
665
666 /* look up the key type to see if it's one of the registered kernel
667 * types */
668 list_for_each_entry(ktype, &key_types_list, link) {
669 if (strcmp(ktype->name, type) == 0)
670 goto found_kernel_type;
671 }
672
673 up_read(&key_types_sem);
674 ktype = ERR_PTR(-ENOKEY);
675
676 found_kernel_type:
677 return ktype;
678
679} /* end key_type_lookup() */
680
681/*****************************************************************************/
682/*
683 * unlock a key type
684 */
685void key_type_put(struct key_type *ktype)
686{
687 up_read(&key_types_sem);
688
689} /* end key_type_put() */
690
691/*****************************************************************************/
692/*
693 * attempt to update an existing key
694 * - the key has an incremented refcount
695 * - we need to put the key if we get an error
696 */
David Howells664cceb2005-09-28 17:03:15 +0100697static inline key_ref_t __key_update(key_ref_t key_ref,
698 const void *payload, size_t plen)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699{
David Howells664cceb2005-09-28 17:03:15 +0100700 struct key *key = key_ref_to_ptr(key_ref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701 int ret;
702
703 /* need write permission on the key to update it */
David Howells29db9192005-10-30 15:02:44 -0800704 ret = key_permission(key_ref, KEY_WRITE);
705 if (ret < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706 goto error;
707
708 ret = -EEXIST;
709 if (!key->type->update)
710 goto error;
711
712 down_write(&key->sem);
713
714 ret = key->type->update(key, payload, plen);
David Howells76d8aea2005-06-23 22:00:49 -0700715 if (ret == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716 /* updating a negative key instantiates it */
David Howells76d8aea2005-06-23 22:00:49 -0700717 clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718
719 up_write(&key->sem);
720
721 if (ret < 0)
722 goto error;
David Howells664cceb2005-09-28 17:03:15 +0100723out:
724 return key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725
David Howells664cceb2005-09-28 17:03:15 +0100726error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 key_put(key);
David Howells664cceb2005-09-28 17:03:15 +0100728 key_ref = ERR_PTR(ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729 goto out;
730
731} /* end __key_update() */
732
733/*****************************************************************************/
734/*
735 * search the specified keyring for a key of the same description; if one is
736 * found, update it, otherwise add a new one
737 */
David Howells664cceb2005-09-28 17:03:15 +0100738key_ref_t key_create_or_update(key_ref_t keyring_ref,
739 const char *type,
740 const char *description,
741 const void *payload,
742 size_t plen,
Arun Raghavan6b79ccb2008-04-29 01:01:28 -0700743 key_perm_t perm,
David Howells7e047ef2006-06-26 00:24:50 -0700744 unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700745{
David Howellsd84f4f92008-11-14 10:39:23 +1100746 const struct cred *cred = current_cred();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747 struct key_type *ktype;
David Howells664cceb2005-09-28 17:03:15 +0100748 struct key *keyring, *key = NULL;
David Howells664cceb2005-09-28 17:03:15 +0100749 key_ref_t key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750 int ret;
751
Linus Torvalds1da177e2005-04-16 15:20:36 -0700752 /* look up the key type to see if it's one of the registered kernel
753 * types */
754 ktype = key_type_lookup(type);
755 if (IS_ERR(ktype)) {
David Howells664cceb2005-09-28 17:03:15 +0100756 key_ref = ERR_PTR(-ENODEV);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757 goto error;
758 }
759
David Howells664cceb2005-09-28 17:03:15 +0100760 key_ref = ERR_PTR(-EINVAL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700761 if (!ktype->match || !ktype->instantiate)
762 goto error_2;
763
David Howells664cceb2005-09-28 17:03:15 +0100764 keyring = key_ref_to_ptr(keyring_ref);
765
766 key_check(keyring);
767
David Howellsc3a9d652006-04-10 15:15:21 +0100768 key_ref = ERR_PTR(-ENOTDIR);
769 if (keyring->type != &key_type_keyring)
770 goto error_2;
771
David Howells664cceb2005-09-28 17:03:15 +0100772 down_write(&keyring->sem);
773
774 /* if we're going to allocate a new key, we're going to have
775 * to modify the keyring */
David Howells29db9192005-10-30 15:02:44 -0800776 ret = key_permission(keyring_ref, KEY_WRITE);
777 if (ret < 0) {
778 key_ref = ERR_PTR(ret);
David Howells664cceb2005-09-28 17:03:15 +0100779 goto error_3;
David Howells29db9192005-10-30 15:02:44 -0800780 }
David Howells664cceb2005-09-28 17:03:15 +0100781
David Howells1d9b7d92006-03-25 03:06:52 -0800782 /* if it's possible to update this type of key, search for an existing
783 * key of the same type and description in the destination keyring and
784 * update that instead if possible
Linus Torvalds1da177e2005-04-16 15:20:36 -0700785 */
David Howells1d9b7d92006-03-25 03:06:52 -0800786 if (ktype->update) {
787 key_ref = __keyring_search_one(keyring_ref, ktype, description,
788 0);
789 if (!IS_ERR(key_ref))
790 goto found_matching_key;
791 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792
Arun Raghavan6b79ccb2008-04-29 01:01:28 -0700793 /* if the client doesn't provide, decide on the permissions we want */
794 if (perm == KEY_PERM_UNDEF) {
795 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
796 perm |= KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK | KEY_USR_SETATTR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797
Arun Raghavan6b79ccb2008-04-29 01:01:28 -0700798 if (ktype->read)
799 perm |= KEY_POS_READ | KEY_USR_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800
Arun Raghavan6b79ccb2008-04-29 01:01:28 -0700801 if (ktype == &key_type_keyring || ktype->update)
802 perm |= KEY_USR_WRITE;
803 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804
805 /* allocate a new key */
David Howellsd84f4f92008-11-14 10:39:23 +1100806 key = key_alloc(ktype, description, cred->fsuid, cred->fsgid, cred,
807 perm, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808 if (IS_ERR(key)) {
David Howellse231c2e2008-02-07 00:15:26 -0800809 key_ref = ERR_CAST(key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810 goto error_3;
811 }
812
813 /* instantiate it and link it into the target keyring */
David Howells3e301482005-06-23 22:00:56 -0700814 ret = __key_instantiate_and_link(key, payload, plen, keyring, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815 if (ret < 0) {
816 key_put(key);
David Howells664cceb2005-09-28 17:03:15 +0100817 key_ref = ERR_PTR(ret);
818 goto error_3;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700819 }
820
David Howells664cceb2005-09-28 17:03:15 +0100821 key_ref = make_key_ref(key, is_key_possessed(keyring_ref));
822
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823 error_3:
824 up_write(&keyring->sem);
825 error_2:
826 key_type_put(ktype);
827 error:
David Howells664cceb2005-09-28 17:03:15 +0100828 return key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829
830 found_matching_key:
831 /* we found a matching key, so we're going to try to update it
832 * - we can drop the locks first as we have the key pinned
833 */
834 up_write(&keyring->sem);
835 key_type_put(ktype);
836
David Howells664cceb2005-09-28 17:03:15 +0100837 key_ref = __key_update(key_ref, payload, plen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838 goto error;
839
840} /* end key_create_or_update() */
841
842EXPORT_SYMBOL(key_create_or_update);
843
844/*****************************************************************************/
845/*
846 * update a key
847 */
David Howells664cceb2005-09-28 17:03:15 +0100848int key_update(key_ref_t key_ref, const void *payload, size_t plen)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849{
David Howells664cceb2005-09-28 17:03:15 +0100850 struct key *key = key_ref_to_ptr(key_ref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851 int ret;
852
853 key_check(key);
854
855 /* the key must be writable */
David Howells29db9192005-10-30 15:02:44 -0800856 ret = key_permission(key_ref, KEY_WRITE);
857 if (ret < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858 goto error;
859
860 /* attempt to update it if supported */
861 ret = -EOPNOTSUPP;
862 if (key->type->update) {
863 down_write(&key->sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864
David Howells29db9192005-10-30 15:02:44 -0800865 ret = key->type->update(key, payload, plen);
David Howells76d8aea2005-06-23 22:00:49 -0700866 if (ret == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867 /* updating a negative key instantiates it */
David Howells76d8aea2005-06-23 22:00:49 -0700868 clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869
870 up_write(&key->sem);
871 }
872
873 error:
874 return ret;
875
876} /* end key_update() */
877
878EXPORT_SYMBOL(key_update);
879
880/*****************************************************************************/
881/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882 * revoke a key
883 */
884void key_revoke(struct key *key)
885{
886 key_check(key);
887
David Howells76181c12007-10-16 23:29:46 -0700888 /* make sure no one's trying to change or use the key when we mark it
889 * - we tell lockdep that we might nest because we might be revoking an
890 * authorisation key whilst holding the sem on a key we've just
891 * instantiated
892 */
893 down_write_nested(&key->sem, 1);
894 if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags) &&
895 key->type->revoke)
David Howells04c567d2006-06-22 14:47:18 -0700896 key->type->revoke(key);
897
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898 up_write(&key->sem);
899
900} /* end key_revoke() */
901
902EXPORT_SYMBOL(key_revoke);
903
904/*****************************************************************************/
905/*
906 * register a type of key
907 */
908int register_key_type(struct key_type *ktype)
909{
910 struct key_type *p;
911 int ret;
912
913 ret = -EEXIST;
914 down_write(&key_types_sem);
915
916 /* disallow key types with the same name */
917 list_for_each_entry(p, &key_types_list, link) {
918 if (strcmp(p->name, ktype->name) == 0)
919 goto out;
920 }
921
922 /* store the type */
923 list_add(&ktype->link, &key_types_list);
924 ret = 0;
925
926 out:
927 up_write(&key_types_sem);
928 return ret;
929
930} /* end register_key_type() */
931
932EXPORT_SYMBOL(register_key_type);
933
934/*****************************************************************************/
935/*
936 * unregister a type of key
937 */
938void unregister_key_type(struct key_type *ktype)
939{
940 struct rb_node *_n;
941 struct key *key;
942
943 down_write(&key_types_sem);
944
945 /* withdraw the key type */
946 list_del_init(&ktype->link);
947
David Howells76d8aea2005-06-23 22:00:49 -0700948 /* mark all the keys of this type dead */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700949 spin_lock(&key_serial_lock);
950
951 for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
952 key = rb_entry(_n, struct key, serial_node);
953
David Howells76d8aea2005-06-23 22:00:49 -0700954 if (key->type == ktype)
955 key->type = &key_type_dead;
956 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700957
David Howells76d8aea2005-06-23 22:00:49 -0700958 spin_unlock(&key_serial_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959
David Howells76d8aea2005-06-23 22:00:49 -0700960 /* make sure everyone revalidates their keys */
Paul E. McKenneyb2b18662005-06-25 14:55:38 -0700961 synchronize_rcu();
David Howells76d8aea2005-06-23 22:00:49 -0700962
963 /* we should now be able to destroy the payloads of all the keys of
964 * this type with impunity */
965 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
970 if (key->type == ktype) {
971 if (ktype->destroy)
972 ktype->destroy(key);
Randy Dunlapa7807a32006-06-27 02:53:54 -0700973 memset(&key->payload, KEY_DESTROY, sizeof(key->payload));
David Howells76d8aea2005-06-23 22:00:49 -0700974 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975 }
976
977 spin_unlock(&key_serial_lock);
978 up_write(&key_types_sem);
979
980} /* end unregister_key_type() */
981
982EXPORT_SYMBOL(unregister_key_type);
983
984/*****************************************************************************/
985/*
986 * initialise the key management stuff
987 */
988void __init key_init(void)
989{
990 /* allocate a slab in which we can store keys */
991 key_jar = kmem_cache_create("key_jar", sizeof(struct key),
Paul Mundt20c2df82007-07-20 10:11:58 +0900992 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700993
994 /* add the special key types */
995 list_add_tail(&key_type_keyring.link, &key_types_list);
996 list_add_tail(&key_type_dead.link, &key_types_list);
997 list_add_tail(&key_type_user.link, &key_types_list);
998
999 /* record the root user tracking */
1000 rb_link_node(&root_key_user.node,
1001 NULL,
1002 &key_user_tree.rb_node);
1003
1004 rb_insert_color(&root_key_user.node,
1005 &key_user_tree);
1006
Linus Torvalds1da177e2005-04-16 15:20:36 -07001007} /* end key_init() */