blob: 50d96d4e06f235c3e8950255c4b8bd5fd64aa7d2 [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
David Howells8bc16de2011-08-22 14:09:11 +010024struct 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 Howells973c9f42011-01-20 16:38:33 +000039/* We serialise key instantiation and link */
David Howells76181c12007-10-16 23:29:46 -070040DEFINE_MUTEX(key_construction_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070041
Linus Torvalds1da177e2005-04-16 15:20:36 -070042#ifdef KEY_DEBUGGING
43void __key_check(const struct key *key)
44{
45 printk("__key_check: key %p {%08x} should be {%08x}\n",
46 key, key->magic, KEY_DEBUG_MAGIC);
47 BUG();
48}
49#endif
50
Linus Torvalds1da177e2005-04-16 15:20:36 -070051/*
David Howells973c9f42011-01-20 16:38:33 +000052 * Get the key quota record for a user, allocating a new record if one doesn't
53 * already exist.
Linus Torvalds1da177e2005-04-16 15:20:36 -070054 */
Serge E. Hallyn1d1e9752009-02-26 18:27:38 -060055struct key_user *key_user_lookup(uid_t uid, struct user_namespace *user_ns)
Linus Torvalds1da177e2005-04-16 15:20:36 -070056{
57 struct key_user *candidate = NULL, *user;
58 struct rb_node *parent = NULL;
59 struct rb_node **p;
60
David Howells973c9f42011-01-20 16:38:33 +000061try_again:
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 p = &key_user_tree.rb_node;
63 spin_lock(&key_user_lock);
64
65 /* search the tree for a user record with a matching UID */
66 while (*p) {
67 parent = *p;
68 user = rb_entry(parent, struct key_user, node);
69
70 if (uid < user->uid)
71 p = &(*p)->rb_left;
72 else if (uid > user->uid)
73 p = &(*p)->rb_right;
Serge E. Hallyn1d1e9752009-02-26 18:27:38 -060074 else if (user_ns < user->user_ns)
75 p = &(*p)->rb_left;
76 else if (user_ns > user->user_ns)
77 p = &(*p)->rb_right;
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 else
79 goto found;
80 }
81
82 /* if we get here, we failed to find a match in the tree */
83 if (!candidate) {
84 /* allocate a candidate user record if we don't already have
85 * one */
86 spin_unlock(&key_user_lock);
87
88 user = NULL;
89 candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL);
90 if (unlikely(!candidate))
91 goto out;
92
93 /* the allocation may have scheduled, so we need to repeat the
94 * search lest someone else added the record whilst we were
95 * asleep */
96 goto try_again;
97 }
98
99 /* if we get here, then the user record still hadn't appeared on the
100 * second pass - so we use the candidate record */
101 atomic_set(&candidate->usage, 1);
102 atomic_set(&candidate->nkeys, 0);
103 atomic_set(&candidate->nikeys, 0);
104 candidate->uid = uid;
Serge E. Hallyn1d1e9752009-02-26 18:27:38 -0600105 candidate->user_ns = get_user_ns(user_ns);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 candidate->qnkeys = 0;
107 candidate->qnbytes = 0;
108 spin_lock_init(&candidate->lock);
David Howells76181c12007-10-16 23:29:46 -0700109 mutex_init(&candidate->cons_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110
111 rb_link_node(&candidate->node, parent, p);
112 rb_insert_color(&candidate->node, &key_user_tree);
113 spin_unlock(&key_user_lock);
114 user = candidate;
115 goto out;
116
117 /* okay - we found a user record for this UID */
David Howells973c9f42011-01-20 16:38:33 +0000118found:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 atomic_inc(&user->usage);
120 spin_unlock(&key_user_lock);
Jesper Juhla7f988b2005-11-07 01:01:35 -0800121 kfree(candidate);
David Howells973c9f42011-01-20 16:38:33 +0000122out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 return user;
David Howellsa8b17ed2011-01-20 16:38:27 +0000124}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126/*
David Howells973c9f42011-01-20 16:38:33 +0000127 * Dispose of a user structure
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 */
129void key_user_put(struct key_user *user)
130{
131 if (atomic_dec_and_lock(&user->usage, &key_user_lock)) {
132 rb_erase(&user->node, &key_user_tree);
133 spin_unlock(&key_user_lock);
Serge E. Hallyn1d1e9752009-02-26 18:27:38 -0600134 put_user_ns(user->user_ns);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135
136 kfree(user);
137 }
David Howellsa8b17ed2011-01-20 16:38:27 +0000138}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140/*
David Howells973c9f42011-01-20 16:38:33 +0000141 * Allocate a serial number for a key. These are assigned randomly to avoid
142 * security issues through covert channel problems.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 */
144static inline void key_alloc_serial(struct key *key)
145{
146 struct rb_node *parent, **p;
147 struct key *xkey;
148
Michael LeMaye51f6d32006-06-26 00:24:54 -0700149 /* propose a random serial number and look for a hole for it in the
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 * serial number tree */
Michael LeMaye51f6d32006-06-26 00:24:54 -0700151 do {
152 get_random_bytes(&key->serial, sizeof(key->serial));
153
154 key->serial >>= 1; /* negative numbers are not permitted */
155 } while (key->serial < 3);
156
157 spin_lock(&key_serial_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158
David Howells9ad08302007-02-06 13:45:51 +0000159attempt_insertion:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 parent = NULL;
161 p = &key_serial_tree.rb_node;
162
163 while (*p) {
164 parent = *p;
165 xkey = rb_entry(parent, struct key, serial_node);
166
167 if (key->serial < xkey->serial)
168 p = &(*p)->rb_left;
169 else if (key->serial > xkey->serial)
170 p = &(*p)->rb_right;
171 else
172 goto serial_exists;
173 }
David Howells9ad08302007-02-06 13:45:51 +0000174
175 /* we've found a suitable hole - arrange for this key to occupy it */
176 rb_link_node(&key->serial_node, parent, p);
177 rb_insert_color(&key->serial_node, &key_serial_tree);
178
179 spin_unlock(&key_serial_lock);
180 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181
182 /* we found a key with the proposed serial number - walk the tree from
183 * that point looking for the next unused serial number */
Michael LeMaye51f6d32006-06-26 00:24:54 -0700184serial_exists:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 for (;;) {
Michael LeMaye51f6d32006-06-26 00:24:54 -0700186 key->serial++;
David Howells9ad08302007-02-06 13:45:51 +0000187 if (key->serial < 3) {
188 key->serial = 3;
189 goto attempt_insertion;
190 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191
192 parent = rb_next(parent);
193 if (!parent)
David Howells9ad08302007-02-06 13:45:51 +0000194 goto attempt_insertion;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195
196 xkey = rb_entry(parent, struct key, serial_node);
197 if (key->serial < xkey->serial)
David Howells9ad08302007-02-06 13:45:51 +0000198 goto attempt_insertion;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 }
David Howellsa8b17ed2011-01-20 16:38:27 +0000200}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201
David Howells973c9f42011-01-20 16:38:33 +0000202/**
203 * key_alloc - Allocate a key of the specified type.
204 * @type: The type of key to allocate.
205 * @desc: The key description to allow the key to be searched out.
206 * @uid: The owner of the new key.
207 * @gid: The group ID for the new key's group permissions.
208 * @cred: The credentials specifying UID namespace.
209 * @perm: The permissions mask of the new key.
210 * @flags: Flags specifying quota properties.
211 *
212 * Allocate a key of the specified type with the attributes given. The key is
213 * returned in an uninstantiated state and the caller needs to instantiate the
214 * key before returning.
215 *
216 * The user's key count quota is updated to reflect the creation of the key and
217 * the user's key data quota has the default for the key type reserved. The
218 * instantiation function should amend this as necessary. If insufficient
219 * quota is available, -EDQUOT will be returned.
220 *
221 * The LSM security modules can prevent a key being created, in which case
222 * -EACCES will be returned.
223 *
224 * Returns a pointer to the new key if successful and an error code otherwise.
225 *
226 * Note that the caller needs to ensure the key type isn't uninstantiated.
227 * Internally this can be done by locking key_types_sem. Externally, this can
228 * be done by either never unregistering the key type, or making sure
229 * key_alloc() calls don't race with module unloading.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 */
231struct key *key_alloc(struct key_type *type, const char *desc,
David Howellsd84f4f92008-11-14 10:39:23 +1100232 uid_t uid, gid_t gid, const struct cred *cred,
David Howells7e047ef2006-06-26 00:24:50 -0700233 key_perm_t perm, unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234{
235 struct key_user *user = NULL;
236 struct key *key;
237 size_t desclen, quotalen;
David Howells29db9192005-10-30 15:02:44 -0800238 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239
240 key = ERR_PTR(-EINVAL);
241 if (!desc || !*desc)
242 goto error;
243
David Howellsb9fffa32011-03-07 15:05:59 +0000244 if (type->vet_description) {
245 ret = type->vet_description(desc);
246 if (ret < 0) {
247 key = ERR_PTR(ret);
248 goto error;
249 }
250 }
251
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 desclen = strlen(desc) + 1;
253 quotalen = desclen + type->def_datalen;
254
255 /* get hold of the key tracking for this user */
Eric W. Biedermanc4a4d602011-11-16 23:15:31 -0800256 user = key_user_lookup(uid, cred->user_ns);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 if (!user)
258 goto no_memory_1;
259
260 /* check that the user's quota permits allocation of another key and
261 * its description */
David Howells7e047ef2006-06-26 00:24:50 -0700262 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
David Howells0b77f5b2008-04-29 01:01:32 -0700263 unsigned maxkeys = (uid == 0) ?
264 key_quota_root_maxkeys : key_quota_maxkeys;
265 unsigned maxbytes = (uid == 0) ?
266 key_quota_root_maxbytes : key_quota_maxbytes;
267
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 spin_lock(&user->lock);
David Howells7e047ef2006-06-26 00:24:50 -0700269 if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) {
David Howells0b77f5b2008-04-29 01:01:32 -0700270 if (user->qnkeys + 1 >= maxkeys ||
271 user->qnbytes + quotalen >= maxbytes ||
272 user->qnbytes + quotalen < user->qnbytes)
David Howells7e047ef2006-06-26 00:24:50 -0700273 goto no_quota;
274 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275
276 user->qnkeys++;
277 user->qnbytes += quotalen;
278 spin_unlock(&user->lock);
279 }
280
281 /* allocate and initialise the key and its description */
Christoph Lametere94b1762006-12-06 20:33:17 -0800282 key = kmem_cache_alloc(key_jar, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283 if (!key)
284 goto no_memory_2;
285
286 if (desc) {
Eric Sesterhenn48ad5042006-12-06 20:33:47 -0800287 key->description = kmemdup(desc, desclen, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 if (!key->description)
289 goto no_memory_3;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 }
291
292 atomic_set(&key->usage, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 init_rwsem(&key->sem);
David Howells7845bc392011-11-16 11:15:54 +0000294 lockdep_set_class(&key->sem, &type->lock_class);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 key->type = type;
296 key->user = user;
297 key->quotalen = quotalen;
298 key->datalen = type->def_datalen;
299 key->uid = uid;
300 key->gid = gid;
301 key->perm = perm;
302 key->flags = 0;
303 key->expiry = 0;
304 key->payload.data = NULL;
David Howells29db9192005-10-30 15:02:44 -0800305 key->security = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306
David Howells7e047ef2006-06-26 00:24:50 -0700307 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA))
David Howells76d8aea2005-06-23 22:00:49 -0700308 key->flags |= 1 << KEY_FLAG_IN_QUOTA;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309
310 memset(&key->type_data, 0, sizeof(key->type_data));
311
312#ifdef KEY_DEBUGGING
313 key->magic = KEY_DEBUG_MAGIC;
314#endif
315
David Howells29db9192005-10-30 15:02:44 -0800316 /* let the security module know about the key */
David Howellsd84f4f92008-11-14 10:39:23 +1100317 ret = security_key_alloc(key, cred, flags);
David Howells29db9192005-10-30 15:02:44 -0800318 if (ret < 0)
319 goto security_error;
320
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 /* publish the key by giving it a serial number */
322 atomic_inc(&user->nkeys);
323 key_alloc_serial(key);
324
David Howells29db9192005-10-30 15:02:44 -0800325error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 return key;
327
David Howells29db9192005-10-30 15:02:44 -0800328security_error:
329 kfree(key->description);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 kmem_cache_free(key_jar, key);
David Howells7e047ef2006-06-26 00:24:50 -0700331 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332 spin_lock(&user->lock);
333 user->qnkeys--;
334 user->qnbytes -= quotalen;
335 spin_unlock(&user->lock);
336 }
337 key_user_put(user);
David Howells29db9192005-10-30 15:02:44 -0800338 key = ERR_PTR(ret);
339 goto error;
340
341no_memory_3:
342 kmem_cache_free(key_jar, key);
343no_memory_2:
David Howells7e047ef2006-06-26 00:24:50 -0700344 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
David Howells29db9192005-10-30 15:02:44 -0800345 spin_lock(&user->lock);
346 user->qnkeys--;
347 user->qnbytes -= quotalen;
348 spin_unlock(&user->lock);
349 }
350 key_user_put(user);
351no_memory_1:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352 key = ERR_PTR(-ENOMEM);
353 goto error;
354
David Howells29db9192005-10-30 15:02:44 -0800355no_quota:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356 spin_unlock(&user->lock);
357 key_user_put(user);
358 key = ERR_PTR(-EDQUOT);
359 goto error;
David Howellsa8b17ed2011-01-20 16:38:27 +0000360}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361EXPORT_SYMBOL(key_alloc);
362
David Howells973c9f42011-01-20 16:38:33 +0000363/**
364 * key_payload_reserve - Adjust data quota reservation for the key's payload
365 * @key: The key to make the reservation for.
366 * @datalen: The amount of data payload the caller now wants.
367 *
368 * Adjust the amount of the owning user's key data quota that a key reserves.
369 * If the amount is increased, then -EDQUOT may be returned if there isn't
370 * enough free quota available.
371 *
372 * If successful, 0 is returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 */
374int key_payload_reserve(struct key *key, size_t datalen)
375{
Justin P. Mattockc5b60b52010-04-21 00:02:11 -0700376 int delta = (int)datalen - key->datalen;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377 int ret = 0;
378
379 key_check(key);
380
381 /* contemplate the quota adjustment */
David Howells76d8aea2005-06-23 22:00:49 -0700382 if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
David Howells0b77f5b2008-04-29 01:01:32 -0700383 unsigned maxbytes = (key->user->uid == 0) ?
384 key_quota_root_maxbytes : key_quota_maxbytes;
385
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386 spin_lock(&key->user->lock);
387
388 if (delta > 0 &&
David Howells0b77f5b2008-04-29 01:01:32 -0700389 (key->user->qnbytes + delta >= maxbytes ||
390 key->user->qnbytes + delta < key->user->qnbytes)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391 ret = -EDQUOT;
392 }
393 else {
394 key->user->qnbytes += delta;
395 key->quotalen += delta;
396 }
397 spin_unlock(&key->user->lock);
398 }
399
400 /* change the recorded data length if that didn't generate an error */
401 if (ret == 0)
402 key->datalen = datalen;
403
404 return ret;
David Howellsa8b17ed2011-01-20 16:38:27 +0000405}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406EXPORT_SYMBOL(key_payload_reserve);
407
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408/*
David Howells973c9f42011-01-20 16:38:33 +0000409 * Instantiate a key and link it into the target keyring atomically. Must be
410 * called with the target keyring's semaphore writelocked. The target key's
411 * semaphore need not be locked as instantiation is serialised by
412 * key_construction_mutex.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 */
414static int __key_instantiate_and_link(struct key *key,
415 const void *data,
416 size_t datalen,
David Howells3e301482005-06-23 22:00:56 -0700417 struct key *keyring,
David Howellsf70e2e02010-04-30 14:32:39 +0100418 struct key *authkey,
David Howellsceb73c12011-01-25 16:34:28 +0000419 unsigned long *_prealloc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420{
421 int ret, awaken;
422
423 key_check(key);
424 key_check(keyring);
425
426 awaken = 0;
427 ret = -EBUSY;
428
David Howells76181c12007-10-16 23:29:46 -0700429 mutex_lock(&key_construction_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430
431 /* can't instantiate twice */
David Howells76d8aea2005-06-23 22:00:49 -0700432 if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 /* instantiate the key */
434 ret = key->type->instantiate(key, data, datalen);
435
436 if (ret == 0) {
437 /* mark the key as being instantiated */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438 atomic_inc(&key->user->nikeys);
David Howells76d8aea2005-06-23 22:00:49 -0700439 set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440
David Howells76d8aea2005-06-23 22:00:49 -0700441 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442 awaken = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443
444 /* and link it into the destination keyring */
445 if (keyring)
David Howellsf70e2e02010-04-30 14:32:39 +0100446 __key_link(keyring, key, _prealloc);
David Howells3e301482005-06-23 22:00:56 -0700447
448 /* disable the authorisation key */
David Howellsd84f4f92008-11-14 10:39:23 +1100449 if (authkey)
450 key_revoke(authkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451 }
452 }
453
David Howells76181c12007-10-16 23:29:46 -0700454 mutex_unlock(&key_construction_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455
456 /* wake up anyone waiting for a key to be constructed */
457 if (awaken)
David Howells76181c12007-10-16 23:29:46 -0700458 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459
460 return ret;
David Howellsa8b17ed2011-01-20 16:38:27 +0000461}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462
David Howells973c9f42011-01-20 16:38:33 +0000463/**
464 * key_instantiate_and_link - Instantiate a key and link it into the keyring.
465 * @key: The key to instantiate.
466 * @data: The data to use to instantiate the keyring.
467 * @datalen: The length of @data.
468 * @keyring: Keyring to create a link in on success (or NULL).
469 * @authkey: The authorisation token permitting instantiation.
470 *
471 * Instantiate a key that's in the uninstantiated state using the provided data
472 * and, if successful, link it in to the destination keyring if one is
473 * supplied.
474 *
475 * If successful, 0 is returned, the authorisation token is revoked and anyone
476 * waiting for the key is woken up. If the key was already instantiated,
477 * -EBUSY will be returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 */
479int key_instantiate_and_link(struct key *key,
480 const void *data,
481 size_t datalen,
David Howells3e301482005-06-23 22:00:56 -0700482 struct key *keyring,
David Howellsd84f4f92008-11-14 10:39:23 +1100483 struct key *authkey)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484{
David Howellsceb73c12011-01-25 16:34:28 +0000485 unsigned long prealloc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486 int ret;
487
David Howellsf70e2e02010-04-30 14:32:39 +0100488 if (keyring) {
489 ret = __key_link_begin(keyring, key->type, key->description,
490 &prealloc);
491 if (ret < 0)
492 return ret;
493 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494
David Howellsf70e2e02010-04-30 14:32:39 +0100495 ret = __key_instantiate_and_link(key, data, datalen, keyring, authkey,
496 &prealloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497
498 if (keyring)
David Howellsf70e2e02010-04-30 14:32:39 +0100499 __key_link_end(keyring, key->type, prealloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500
501 return ret;
David Howellsa8b17ed2011-01-20 16:38:27 +0000502}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503
504EXPORT_SYMBOL(key_instantiate_and_link);
505
David Howells973c9f42011-01-20 16:38:33 +0000506/**
David Howellsfdd1b942011-03-07 15:06:09 +0000507 * key_reject_and_link - Negatively instantiate a key and link it into the keyring.
David Howells973c9f42011-01-20 16:38:33 +0000508 * @key: The key to instantiate.
509 * @timeout: The timeout on the negative key.
David Howellsfdd1b942011-03-07 15:06:09 +0000510 * @error: The error to return when the key is hit.
David Howells973c9f42011-01-20 16:38:33 +0000511 * @keyring: Keyring to create a link in on success (or NULL).
512 * @authkey: The authorisation token permitting instantiation.
513 *
514 * Negatively instantiate a key that's in the uninstantiated state and, if
David Howellsfdd1b942011-03-07 15:06:09 +0000515 * successful, set its timeout and stored error and link it in to the
516 * destination keyring if one is supplied. The key and any links to the key
517 * will be automatically garbage collected after the timeout expires.
David Howells973c9f42011-01-20 16:38:33 +0000518 *
519 * Negative keys are used to rate limit repeated request_key() calls by causing
David Howellsfdd1b942011-03-07 15:06:09 +0000520 * them to return the stored error code (typically ENOKEY) until the negative
521 * key expires.
David Howells973c9f42011-01-20 16:38:33 +0000522 *
523 * If successful, 0 is returned, the authorisation token is revoked and anyone
524 * waiting for the key is woken up. If the key was already instantiated,
525 * -EBUSY will be returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 */
David Howellsfdd1b942011-03-07 15:06:09 +0000527int key_reject_and_link(struct key *key,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 unsigned timeout,
David Howellsfdd1b942011-03-07 15:06:09 +0000529 unsigned error,
David Howells3e301482005-06-23 22:00:56 -0700530 struct key *keyring,
David Howellsd84f4f92008-11-14 10:39:23 +1100531 struct key *authkey)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532{
David Howellsceb73c12011-01-25 16:34:28 +0000533 unsigned long prealloc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 struct timespec now;
David Howellsf70e2e02010-04-30 14:32:39 +0100535 int ret, awaken, link_ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536
537 key_check(key);
538 key_check(keyring);
539
540 awaken = 0;
541 ret = -EBUSY;
542
543 if (keyring)
David Howellsf70e2e02010-04-30 14:32:39 +0100544 link_ret = __key_link_begin(keyring, key->type,
545 key->description, &prealloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546
David Howells76181c12007-10-16 23:29:46 -0700547 mutex_lock(&key_construction_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548
549 /* can't instantiate twice */
David Howells76d8aea2005-06-23 22:00:49 -0700550 if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 /* mark the key as being negatively instantiated */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552 atomic_inc(&key->user->nikeys);
David Howells76d8aea2005-06-23 22:00:49 -0700553 set_bit(KEY_FLAG_NEGATIVE, &key->flags);
554 set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
David Howellsfdd1b942011-03-07 15:06:09 +0000555 key->type_data.reject_error = -error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 now = current_kernel_time();
557 key->expiry = now.tv_sec + timeout;
David Howellsc08ef802009-09-14 17:26:13 +0100558 key_schedule_gc(key->expiry + key_gc_delay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559
David Howells76d8aea2005-06-23 22:00:49 -0700560 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561 awaken = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563 ret = 0;
564
565 /* and link it into the destination keyring */
David Howellsf70e2e02010-04-30 14:32:39 +0100566 if (keyring && link_ret == 0)
567 __key_link(keyring, key, &prealloc);
David Howells3e301482005-06-23 22:00:56 -0700568
569 /* disable the authorisation key */
David Howellsd84f4f92008-11-14 10:39:23 +1100570 if (authkey)
571 key_revoke(authkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572 }
573
David Howells76181c12007-10-16 23:29:46 -0700574 mutex_unlock(&key_construction_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575
576 if (keyring)
David Howellsf70e2e02010-04-30 14:32:39 +0100577 __key_link_end(keyring, key->type, prealloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578
579 /* wake up anyone waiting for a key to be constructed */
580 if (awaken)
David Howells76181c12007-10-16 23:29:46 -0700581 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582
David Howellsf70e2e02010-04-30 14:32:39 +0100583 return ret == 0 ? link_ret : ret;
David Howellsa8b17ed2011-01-20 16:38:27 +0000584}
David Howellsfdd1b942011-03-07 15:06:09 +0000585EXPORT_SYMBOL(key_reject_and_link);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586
David Howells973c9f42011-01-20 16:38:33 +0000587/**
588 * key_put - Discard a reference to a key.
589 * @key: The key to discard a reference from.
590 *
591 * Discard a reference to a key, and when all the references are gone, we
592 * schedule the cleanup task to come and pull it out of the tree in process
593 * context at some later time.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594 */
595void key_put(struct key *key)
596{
597 if (key) {
598 key_check(key);
599
600 if (atomic_dec_and_test(&key->usage))
David Howells0c061b52011-08-22 14:09:36 +0100601 queue_work(system_nrt_wq, &key_gc_work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 }
David Howellsa8b17ed2011-01-20 16:38:27 +0000603}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604EXPORT_SYMBOL(key_put);
605
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606/*
David Howells973c9f42011-01-20 16:38:33 +0000607 * Find a key by its serial number.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 */
609struct key *key_lookup(key_serial_t id)
610{
611 struct rb_node *n;
612 struct key *key;
613
614 spin_lock(&key_serial_lock);
615
616 /* search the tree for the specified key */
617 n = key_serial_tree.rb_node;
618 while (n) {
619 key = rb_entry(n, struct key, serial_node);
620
621 if (id < key->serial)
622 n = n->rb_left;
623 else if (id > key->serial)
624 n = n->rb_right;
625 else
626 goto found;
627 }
628
David Howells973c9f42011-01-20 16:38:33 +0000629not_found:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630 key = ERR_PTR(-ENOKEY);
631 goto error;
632
David Howells973c9f42011-01-20 16:38:33 +0000633found:
David Howells55931222009-09-02 09:13:45 +0100634 /* pretend it doesn't exist if it is awaiting deletion */
635 if (atomic_read(&key->usage) == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636 goto not_found;
637
638 /* this races with key_put(), but that doesn't matter since key_put()
639 * doesn't actually change the key
640 */
641 atomic_inc(&key->usage);
642
David Howells973c9f42011-01-20 16:38:33 +0000643error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644 spin_unlock(&key_serial_lock);
645 return key;
David Howellsa8b17ed2011-01-20 16:38:27 +0000646}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648/*
David Howells973c9f42011-01-20 16:38:33 +0000649 * Find and lock the specified key type against removal.
650 *
651 * We return with the sem read-locked if successful. If the type wasn't
652 * available -ENOKEY is returned instead.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653 */
654struct key_type *key_type_lookup(const char *type)
655{
656 struct key_type *ktype;
657
658 down_read(&key_types_sem);
659
660 /* look up the key type to see if it's one of the registered kernel
661 * types */
662 list_for_each_entry(ktype, &key_types_list, link) {
663 if (strcmp(ktype->name, type) == 0)
664 goto found_kernel_type;
665 }
666
667 up_read(&key_types_sem);
668 ktype = ERR_PTR(-ENOKEY);
669
David Howells973c9f42011-01-20 16:38:33 +0000670found_kernel_type:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671 return ktype;
David Howellsa8b17ed2011-01-20 16:38:27 +0000672}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673
Bryan Schumaker59e6b9c2012-02-24 14:14:50 -0500674void key_set_timeout(struct key *key, unsigned timeout)
675{
676 struct timespec now;
677 time_t expiry = 0;
678
679 /* make the changes with the locks held to prevent races */
680 down_write(&key->sem);
681
682 if (timeout > 0) {
683 now = current_kernel_time();
684 expiry = now.tv_sec + timeout;
685 }
686
687 key->expiry = expiry;
688 key_schedule_gc(key->expiry + key_gc_delay);
689
690 up_write(&key->sem);
691}
692EXPORT_SYMBOL_GPL(key_set_timeout);
693
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694/*
David Howells973c9f42011-01-20 16:38:33 +0000695 * Unlock a key type locked by key_type_lookup().
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696 */
697void key_type_put(struct key_type *ktype)
698{
699 up_read(&key_types_sem);
David Howellsa8b17ed2011-01-20 16:38:27 +0000700}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702/*
David Howells973c9f42011-01-20 16:38:33 +0000703 * Attempt to update an existing key.
704 *
705 * The key is given to us with an incremented refcount that we need to discard
706 * if we get an error.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 */
David Howells664cceb2005-09-28 17:03:15 +0100708static inline key_ref_t __key_update(key_ref_t key_ref,
709 const void *payload, size_t plen)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710{
David Howells664cceb2005-09-28 17:03:15 +0100711 struct key *key = key_ref_to_ptr(key_ref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712 int ret;
713
714 /* need write permission on the key to update it */
David Howells29db9192005-10-30 15:02:44 -0800715 ret = key_permission(key_ref, KEY_WRITE);
716 if (ret < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717 goto error;
718
719 ret = -EEXIST;
720 if (!key->type->update)
721 goto error;
722
723 down_write(&key->sem);
724
725 ret = key->type->update(key, payload, plen);
David Howells76d8aea2005-06-23 22:00:49 -0700726 if (ret == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 /* updating a negative key instantiates it */
David Howells76d8aea2005-06-23 22:00:49 -0700728 clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729
730 up_write(&key->sem);
731
732 if (ret < 0)
733 goto error;
David Howells664cceb2005-09-28 17:03:15 +0100734out:
735 return key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736
David Howells664cceb2005-09-28 17:03:15 +0100737error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738 key_put(key);
David Howells664cceb2005-09-28 17:03:15 +0100739 key_ref = ERR_PTR(ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740 goto out;
David Howellsa8b17ed2011-01-20 16:38:27 +0000741}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742
David Howells973c9f42011-01-20 16:38:33 +0000743/**
744 * key_create_or_update - Update or create and instantiate a key.
745 * @keyring_ref: A pointer to the destination keyring with possession flag.
746 * @type: The type of key.
747 * @description: The searchable description for the key.
748 * @payload: The data to use to instantiate or update the key.
749 * @plen: The length of @payload.
750 * @perm: The permissions mask for a new key.
751 * @flags: The quota flags for a new key.
752 *
753 * Search the destination keyring for a key of the same description and if one
754 * is found, update it, otherwise create and instantiate a new one and create a
755 * link to it from that keyring.
756 *
757 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
758 * concocted.
759 *
760 * Returns a pointer to the new key if successful, -ENODEV if the key type
761 * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the
762 * caller isn't permitted to modify the keyring or the LSM did not permit
763 * creation of the key.
764 *
765 * On success, the possession flag from the keyring ref will be tacked on to
766 * the key ref before it is returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767 */
David Howells664cceb2005-09-28 17:03:15 +0100768key_ref_t key_create_or_update(key_ref_t keyring_ref,
769 const char *type,
770 const char *description,
771 const void *payload,
772 size_t plen,
Arun Raghavan6b79ccb2008-04-29 01:01:28 -0700773 key_perm_t perm,
David Howells7e047ef2006-06-26 00:24:50 -0700774 unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775{
David Howellsceb73c12011-01-25 16:34:28 +0000776 unsigned long prealloc;
David Howellsd84f4f92008-11-14 10:39:23 +1100777 const struct cred *cred = current_cred();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778 struct key_type *ktype;
David Howells664cceb2005-09-28 17:03:15 +0100779 struct key *keyring, *key = NULL;
David Howells664cceb2005-09-28 17:03:15 +0100780 key_ref_t key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781 int ret;
782
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783 /* look up the key type to see if it's one of the registered kernel
784 * types */
785 ktype = key_type_lookup(type);
786 if (IS_ERR(ktype)) {
David Howells664cceb2005-09-28 17:03:15 +0100787 key_ref = ERR_PTR(-ENODEV);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 goto error;
789 }
790
David Howells664cceb2005-09-28 17:03:15 +0100791 key_ref = ERR_PTR(-EINVAL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792 if (!ktype->match || !ktype->instantiate)
793 goto error_2;
794
David Howells664cceb2005-09-28 17:03:15 +0100795 keyring = key_ref_to_ptr(keyring_ref);
796
797 key_check(keyring);
798
David Howellsc3a9d652006-04-10 15:15:21 +0100799 key_ref = ERR_PTR(-ENOTDIR);
800 if (keyring->type != &key_type_keyring)
801 goto error_2;
802
David Howellsf70e2e02010-04-30 14:32:39 +0100803 ret = __key_link_begin(keyring, ktype, description, &prealloc);
804 if (ret < 0)
805 goto error_2;
David Howells664cceb2005-09-28 17:03:15 +0100806
807 /* if we're going to allocate a new key, we're going to have
808 * to modify the keyring */
David Howells29db9192005-10-30 15:02:44 -0800809 ret = key_permission(keyring_ref, KEY_WRITE);
810 if (ret < 0) {
811 key_ref = ERR_PTR(ret);
David Howells664cceb2005-09-28 17:03:15 +0100812 goto error_3;
David Howells29db9192005-10-30 15:02:44 -0800813 }
David Howells664cceb2005-09-28 17:03:15 +0100814
David Howells1d9b7d92006-03-25 03:06:52 -0800815 /* if it's possible to update this type of key, search for an existing
816 * key of the same type and description in the destination keyring and
817 * update that instead if possible
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818 */
David Howells1d9b7d92006-03-25 03:06:52 -0800819 if (ktype->update) {
820 key_ref = __keyring_search_one(keyring_ref, ktype, description,
821 0);
822 if (!IS_ERR(key_ref))
823 goto found_matching_key;
824 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825
Arun Raghavan6b79ccb2008-04-29 01:01:28 -0700826 /* if the client doesn't provide, decide on the permissions we want */
827 if (perm == KEY_PERM_UNDEF) {
828 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
829 perm |= KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK | KEY_USR_SETATTR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830
Arun Raghavan6b79ccb2008-04-29 01:01:28 -0700831 if (ktype->read)
832 perm |= KEY_POS_READ | KEY_USR_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833
Arun Raghavan6b79ccb2008-04-29 01:01:28 -0700834 if (ktype == &key_type_keyring || ktype->update)
835 perm |= KEY_USR_WRITE;
836 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837
838 /* allocate a new key */
David Howellsd84f4f92008-11-14 10:39:23 +1100839 key = key_alloc(ktype, description, cred->fsuid, cred->fsgid, cred,
840 perm, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841 if (IS_ERR(key)) {
David Howellse231c2e2008-02-07 00:15:26 -0800842 key_ref = ERR_CAST(key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843 goto error_3;
844 }
845
846 /* instantiate it and link it into the target keyring */
David Howellsf70e2e02010-04-30 14:32:39 +0100847 ret = __key_instantiate_and_link(key, payload, plen, keyring, NULL,
848 &prealloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849 if (ret < 0) {
850 key_put(key);
David Howells664cceb2005-09-28 17:03:15 +0100851 key_ref = ERR_PTR(ret);
852 goto error_3;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853 }
854
David Howells664cceb2005-09-28 17:03:15 +0100855 key_ref = make_key_ref(key, is_key_possessed(keyring_ref));
856
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857 error_3:
David Howellsf70e2e02010-04-30 14:32:39 +0100858 __key_link_end(keyring, ktype, prealloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859 error_2:
860 key_type_put(ktype);
861 error:
David Howells664cceb2005-09-28 17:03:15 +0100862 return key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863
864 found_matching_key:
865 /* we found a matching key, so we're going to try to update it
866 * - we can drop the locks first as we have the key pinned
867 */
David Howellsf70e2e02010-04-30 14:32:39 +0100868 __key_link_end(keyring, ktype, prealloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869 key_type_put(ktype);
870
David Howells664cceb2005-09-28 17:03:15 +0100871 key_ref = __key_update(key_ref, payload, plen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872 goto error;
David Howellsa8b17ed2011-01-20 16:38:27 +0000873}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700874EXPORT_SYMBOL(key_create_or_update);
875
David Howells973c9f42011-01-20 16:38:33 +0000876/**
877 * key_update - Update a key's contents.
878 * @key_ref: The pointer (plus possession flag) to the key.
879 * @payload: The data to be used to update the key.
880 * @plen: The length of @payload.
881 *
882 * Attempt to update the contents of a key with the given payload data. The
883 * caller must be granted Write permission on the key. Negative keys can be
884 * instantiated by this method.
885 *
886 * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key
887 * type does not support updating. The key type may return other errors.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700888 */
David Howells664cceb2005-09-28 17:03:15 +0100889int key_update(key_ref_t key_ref, const void *payload, size_t plen)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700890{
David Howells664cceb2005-09-28 17:03:15 +0100891 struct key *key = key_ref_to_ptr(key_ref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892 int ret;
893
894 key_check(key);
895
896 /* the key must be writable */
David Howells29db9192005-10-30 15:02:44 -0800897 ret = key_permission(key_ref, KEY_WRITE);
898 if (ret < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899 goto error;
900
901 /* attempt to update it if supported */
902 ret = -EOPNOTSUPP;
903 if (key->type->update) {
904 down_write(&key->sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905
David Howells29db9192005-10-30 15:02:44 -0800906 ret = key->type->update(key, payload, plen);
David Howells76d8aea2005-06-23 22:00:49 -0700907 if (ret == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908 /* updating a negative key instantiates it */
David Howells76d8aea2005-06-23 22:00:49 -0700909 clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910
911 up_write(&key->sem);
912 }
913
914 error:
915 return ret;
David Howellsa8b17ed2011-01-20 16:38:27 +0000916}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917EXPORT_SYMBOL(key_update);
918
David Howells973c9f42011-01-20 16:38:33 +0000919/**
920 * key_revoke - Revoke a key.
921 * @key: The key to be revoked.
922 *
923 * Mark a key as being revoked and ask the type to free up its resources. The
924 * revocation timeout is set and the key and all its links will be
925 * automatically garbage collected after key_gc_delay amount of time if they
926 * are not manually dealt with first.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927 */
928void key_revoke(struct key *key)
929{
David Howells5d135442009-09-02 09:14:00 +0100930 struct timespec now;
931 time_t time;
932
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933 key_check(key);
934
David Howells76181c12007-10-16 23:29:46 -0700935 /* make sure no one's trying to change or use the key when we mark it
936 * - we tell lockdep that we might nest because we might be revoking an
937 * authorisation key whilst holding the sem on a key we've just
938 * instantiated
939 */
940 down_write_nested(&key->sem, 1);
941 if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags) &&
942 key->type->revoke)
David Howells04c567d2006-06-22 14:47:18 -0700943 key->type->revoke(key);
944
David Howells5d135442009-09-02 09:14:00 +0100945 /* set the death time to no more than the expiry time */
946 now = current_kernel_time();
947 time = now.tv_sec;
948 if (key->revoked_at == 0 || key->revoked_at > time) {
949 key->revoked_at = time;
David Howellsc08ef802009-09-14 17:26:13 +0100950 key_schedule_gc(key->revoked_at + key_gc_delay);
David Howells5d135442009-09-02 09:14:00 +0100951 }
952
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953 up_write(&key->sem);
David Howellsa8b17ed2011-01-20 16:38:27 +0000954}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955EXPORT_SYMBOL(key_revoke);
956
David Howells973c9f42011-01-20 16:38:33 +0000957/**
David Howellsfd758152012-05-11 10:56:56 +0100958 * key_invalidate - Invalidate a key.
959 * @key: The key to be invalidated.
960 *
961 * Mark a key as being invalidated and have it cleaned up immediately. The key
962 * is ignored by all searches and other operations from this point.
963 */
964void key_invalidate(struct key *key)
965{
966 kenter("%d", key_serial(key));
967
968 key_check(key);
969
970 if (!test_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
971 down_write_nested(&key->sem, 1);
972 if (!test_and_set_bit(KEY_FLAG_INVALIDATED, &key->flags))
973 key_schedule_gc_links();
974 up_write(&key->sem);
975 }
976}
977EXPORT_SYMBOL(key_invalidate);
978
979/**
David Howells973c9f42011-01-20 16:38:33 +0000980 * register_key_type - Register a type of key.
981 * @ktype: The new key type.
982 *
983 * Register a new key type.
984 *
985 * Returns 0 on success or -EEXIST if a type of this name already exists.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986 */
987int register_key_type(struct key_type *ktype)
988{
989 struct key_type *p;
990 int ret;
991
David Howells7845bc392011-11-16 11:15:54 +0000992 memset(&ktype->lock_class, 0, sizeof(ktype->lock_class));
993
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994 ret = -EEXIST;
995 down_write(&key_types_sem);
996
997 /* disallow key types with the same name */
998 list_for_each_entry(p, &key_types_list, link) {
999 if (strcmp(p->name, ktype->name) == 0)
1000 goto out;
1001 }
1002
1003 /* store the type */
1004 list_add(&ktype->link, &key_types_list);
David Howells1eb1bcf2012-05-11 10:56:56 +01001005
1006 pr_notice("Key type %s registered\n", ktype->name);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001007 ret = 0;
1008
David Howells973c9f42011-01-20 16:38:33 +00001009out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010 up_write(&key_types_sem);
1011 return ret;
David Howellsa8b17ed2011-01-20 16:38:27 +00001012}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001013EXPORT_SYMBOL(register_key_type);
1014
David Howells973c9f42011-01-20 16:38:33 +00001015/**
1016 * unregister_key_type - Unregister a type of key.
1017 * @ktype: The key type.
1018 *
1019 * Unregister a key type and mark all the extant keys of this type as dead.
1020 * Those keys of this type are then destroyed to get rid of their payloads and
1021 * they and their links will be garbage collected as soon as possible.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001022 */
1023void unregister_key_type(struct key_type *ktype)
1024{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001025 down_write(&key_types_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001026 list_del_init(&ktype->link);
David Howells0c061b52011-08-22 14:09:36 +01001027 downgrade_write(&key_types_sem);
1028 key_gc_keytype(ktype);
David Howells1eb1bcf2012-05-11 10:56:56 +01001029 pr_notice("Key type %s unregistered\n", ktype->name);
David Howells0c061b52011-08-22 14:09:36 +01001030 up_read(&key_types_sem);
David Howellsa8b17ed2011-01-20 16:38:27 +00001031}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001032EXPORT_SYMBOL(unregister_key_type);
1033
Linus Torvalds1da177e2005-04-16 15:20:36 -07001034/*
David Howells973c9f42011-01-20 16:38:33 +00001035 * Initialise the key management state.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001036 */
1037void __init key_init(void)
1038{
1039 /* allocate a slab in which we can store keys */
1040 key_jar = kmem_cache_create("key_jar", sizeof(struct key),
Paul Mundt20c2df82007-07-20 10:11:58 +09001041 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001042
1043 /* add the special key types */
1044 list_add_tail(&key_type_keyring.link, &key_types_list);
1045 list_add_tail(&key_type_dead.link, &key_types_list);
1046 list_add_tail(&key_type_user.link, &key_types_list);
Jeff Layton9f6ed2c2012-01-17 16:09:11 -05001047 list_add_tail(&key_type_logon.link, &key_types_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001048
1049 /* record the root user tracking */
1050 rb_link_node(&root_key_user.node,
1051 NULL,
1052 &key_user_tree.rb_node);
1053
1054 rb_insert_color(&root_key_user.node,
1055 &key_user_tree);
David Howellsa8b17ed2011-01-20 16:38:27 +00001056}