Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* key.c: basic authentication token and access key management |
| 2 | * |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 3 | * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4 | * Written by David Howells (dhowells@redhat.com) |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License |
| 8 | * as published by the Free Software Foundation; either version |
| 9 | * 2 of the License, or (at your option) any later version. |
| 10 | */ |
| 11 | |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/init.h> |
| 14 | #include <linux/sched.h> |
| 15 | #include <linux/slab.h> |
| 16 | #include <linux/workqueue.h> |
| 17 | #include <linux/err.h> |
| 18 | #include "internal.h" |
| 19 | |
| 20 | static kmem_cache_t *key_jar; |
| 21 | static key_serial_t key_serial_next = 3; |
| 22 | struct rb_root key_serial_tree; /* tree of keys indexed by serial */ |
| 23 | DEFINE_SPINLOCK(key_serial_lock); |
| 24 | |
| 25 | struct rb_root key_user_tree; /* tree of quota records indexed by UID */ |
| 26 | DEFINE_SPINLOCK(key_user_lock); |
| 27 | |
| 28 | static LIST_HEAD(key_types_list); |
| 29 | static DECLARE_RWSEM(key_types_sem); |
| 30 | |
| 31 | static void key_cleanup(void *data); |
| 32 | static DECLARE_WORK(key_cleanup_task, key_cleanup, NULL); |
| 33 | |
| 34 | /* we serialise key instantiation and link */ |
| 35 | DECLARE_RWSEM(key_construction_sem); |
| 36 | |
| 37 | /* any key who's type gets unegistered will be re-typed to this */ |
| 38 | struct key_type key_type_dead = { |
| 39 | .name = "dead", |
| 40 | }; |
| 41 | |
| 42 | #ifdef KEY_DEBUGGING |
| 43 | void __key_check(const struct key *key) |
| 44 | { |
| 45 | printk("__key_check: key %p {%08x} should be {%08x}\n", |
| 46 | key, key->magic, KEY_DEBUG_MAGIC); |
| 47 | BUG(); |
| 48 | } |
| 49 | #endif |
| 50 | |
| 51 | /*****************************************************************************/ |
| 52 | /* |
| 53 | * get the key quota record for a user, allocating a new record if one doesn't |
| 54 | * already exist |
| 55 | */ |
| 56 | struct key_user *key_user_lookup(uid_t uid) |
| 57 | { |
| 58 | struct key_user *candidate = NULL, *user; |
| 59 | struct rb_node *parent = NULL; |
| 60 | struct rb_node **p; |
| 61 | |
| 62 | try_again: |
| 63 | p = &key_user_tree.rb_node; |
| 64 | spin_lock(&key_user_lock); |
| 65 | |
| 66 | /* search the tree for a user record with a matching UID */ |
| 67 | while (*p) { |
| 68 | parent = *p; |
| 69 | user = rb_entry(parent, struct key_user, node); |
| 70 | |
| 71 | if (uid < user->uid) |
| 72 | p = &(*p)->rb_left; |
| 73 | else if (uid > user->uid) |
| 74 | p = &(*p)->rb_right; |
| 75 | else |
| 76 | goto found; |
| 77 | } |
| 78 | |
| 79 | /* if we get here, we failed to find a match in the tree */ |
| 80 | if (!candidate) { |
| 81 | /* allocate a candidate user record if we don't already have |
| 82 | * one */ |
| 83 | spin_unlock(&key_user_lock); |
| 84 | |
| 85 | user = NULL; |
| 86 | candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL); |
| 87 | if (unlikely(!candidate)) |
| 88 | goto out; |
| 89 | |
| 90 | /* the allocation may have scheduled, so we need to repeat the |
| 91 | * search lest someone else added the record whilst we were |
| 92 | * asleep */ |
| 93 | goto try_again; |
| 94 | } |
| 95 | |
| 96 | /* if we get here, then the user record still hadn't appeared on the |
| 97 | * second pass - so we use the candidate record */ |
| 98 | atomic_set(&candidate->usage, 1); |
| 99 | atomic_set(&candidate->nkeys, 0); |
| 100 | atomic_set(&candidate->nikeys, 0); |
| 101 | candidate->uid = uid; |
| 102 | candidate->qnkeys = 0; |
| 103 | candidate->qnbytes = 0; |
| 104 | spin_lock_init(&candidate->lock); |
| 105 | INIT_LIST_HEAD(&candidate->consq); |
| 106 | |
| 107 | rb_link_node(&candidate->node, parent, p); |
| 108 | rb_insert_color(&candidate->node, &key_user_tree); |
| 109 | spin_unlock(&key_user_lock); |
| 110 | user = candidate; |
| 111 | goto out; |
| 112 | |
| 113 | /* okay - we found a user record for this UID */ |
| 114 | found: |
| 115 | atomic_inc(&user->usage); |
| 116 | spin_unlock(&key_user_lock); |
| 117 | if (candidate) |
| 118 | kfree(candidate); |
| 119 | out: |
| 120 | return user; |
| 121 | |
| 122 | } /* end key_user_lookup() */ |
| 123 | |
| 124 | /*****************************************************************************/ |
| 125 | /* |
| 126 | * dispose of a user structure |
| 127 | */ |
| 128 | void key_user_put(struct key_user *user) |
| 129 | { |
| 130 | if (atomic_dec_and_lock(&user->usage, &key_user_lock)) { |
| 131 | rb_erase(&user->node, &key_user_tree); |
| 132 | spin_unlock(&key_user_lock); |
| 133 | |
| 134 | kfree(user); |
| 135 | } |
| 136 | |
| 137 | } /* end key_user_put() */ |
| 138 | |
| 139 | /*****************************************************************************/ |
| 140 | /* |
| 141 | * insert a key with a fixed serial number |
| 142 | */ |
| 143 | static void __init __key_insert_serial(struct key *key) |
| 144 | { |
| 145 | struct rb_node *parent, **p; |
| 146 | struct key *xkey; |
| 147 | |
| 148 | parent = NULL; |
| 149 | p = &key_serial_tree.rb_node; |
| 150 | |
| 151 | while (*p) { |
| 152 | parent = *p; |
| 153 | xkey = rb_entry(parent, struct key, serial_node); |
| 154 | |
| 155 | if (key->serial < xkey->serial) |
| 156 | p = &(*p)->rb_left; |
| 157 | else if (key->serial > xkey->serial) |
| 158 | p = &(*p)->rb_right; |
| 159 | else |
| 160 | BUG(); |
| 161 | } |
| 162 | |
| 163 | /* we've found a suitable hole - arrange for this key to occupy it */ |
| 164 | rb_link_node(&key->serial_node, parent, p); |
| 165 | rb_insert_color(&key->serial_node, &key_serial_tree); |
| 166 | |
| 167 | } /* end __key_insert_serial() */ |
| 168 | |
| 169 | /*****************************************************************************/ |
| 170 | /* |
| 171 | * assign a key the next unique serial number |
| 172 | * - we work through all the serial numbers between 2 and 2^31-1 in turn and |
| 173 | * then wrap |
| 174 | */ |
| 175 | static inline void key_alloc_serial(struct key *key) |
| 176 | { |
| 177 | struct rb_node *parent, **p; |
| 178 | struct key *xkey; |
| 179 | |
| 180 | spin_lock(&key_serial_lock); |
| 181 | |
| 182 | /* propose a likely serial number and look for a hole for it in the |
| 183 | * serial number tree */ |
| 184 | key->serial = key_serial_next; |
| 185 | if (key->serial < 3) |
| 186 | key->serial = 3; |
| 187 | key_serial_next = key->serial + 1; |
| 188 | |
| 189 | parent = NULL; |
| 190 | p = &key_serial_tree.rb_node; |
| 191 | |
| 192 | while (*p) { |
| 193 | parent = *p; |
| 194 | xkey = rb_entry(parent, struct key, serial_node); |
| 195 | |
| 196 | if (key->serial < xkey->serial) |
| 197 | p = &(*p)->rb_left; |
| 198 | else if (key->serial > xkey->serial) |
| 199 | p = &(*p)->rb_right; |
| 200 | else |
| 201 | goto serial_exists; |
| 202 | } |
| 203 | goto insert_here; |
| 204 | |
| 205 | /* we found a key with the proposed serial number - walk the tree from |
| 206 | * that point looking for the next unused serial number */ |
| 207 | serial_exists: |
| 208 | for (;;) { |
| 209 | key->serial = key_serial_next; |
| 210 | if (key->serial < 2) |
| 211 | key->serial = 2; |
| 212 | key_serial_next = key->serial + 1; |
| 213 | |
| 214 | if (!parent->rb_parent) |
| 215 | p = &key_serial_tree.rb_node; |
| 216 | else if (parent->rb_parent->rb_left == parent) |
| 217 | p = &parent->rb_parent->rb_left; |
| 218 | else |
| 219 | p = &parent->rb_parent->rb_right; |
| 220 | |
| 221 | parent = rb_next(parent); |
| 222 | if (!parent) |
| 223 | break; |
| 224 | |
| 225 | xkey = rb_entry(parent, struct key, serial_node); |
| 226 | if (key->serial < xkey->serial) |
| 227 | goto insert_here; |
| 228 | } |
| 229 | |
| 230 | /* we've found a suitable hole - arrange for this key to occupy it */ |
| 231 | insert_here: |
| 232 | rb_link_node(&key->serial_node, parent, p); |
| 233 | rb_insert_color(&key->serial_node, &key_serial_tree); |
| 234 | |
| 235 | spin_unlock(&key_serial_lock); |
| 236 | |
| 237 | } /* end key_alloc_serial() */ |
| 238 | |
| 239 | /*****************************************************************************/ |
| 240 | /* |
| 241 | * allocate a key of the specified type |
| 242 | * - update the user's quota to reflect the existence of the key |
| 243 | * - called from a key-type operation with key_types_sem read-locked by either |
| 244 | * key_create_or_update() or by key_duplicate(); this prevents unregistration |
| 245 | * of the key type |
| 246 | * - upon return the key is as yet uninstantiated; the caller needs to either |
| 247 | * instantiate the key or discard it before returning |
| 248 | */ |
| 249 | struct key *key_alloc(struct key_type *type, const char *desc, |
| 250 | uid_t uid, gid_t gid, key_perm_t perm, |
| 251 | int not_in_quota) |
| 252 | { |
| 253 | struct key_user *user = NULL; |
| 254 | struct key *key; |
| 255 | size_t desclen, quotalen; |
| 256 | |
| 257 | key = ERR_PTR(-EINVAL); |
| 258 | if (!desc || !*desc) |
| 259 | goto error; |
| 260 | |
| 261 | desclen = strlen(desc) + 1; |
| 262 | quotalen = desclen + type->def_datalen; |
| 263 | |
| 264 | /* get hold of the key tracking for this user */ |
| 265 | user = key_user_lookup(uid); |
| 266 | if (!user) |
| 267 | goto no_memory_1; |
| 268 | |
| 269 | /* check that the user's quota permits allocation of another key and |
| 270 | * its description */ |
| 271 | if (!not_in_quota) { |
| 272 | spin_lock(&user->lock); |
| 273 | if (user->qnkeys + 1 >= KEYQUOTA_MAX_KEYS && |
| 274 | user->qnbytes + quotalen >= KEYQUOTA_MAX_BYTES |
| 275 | ) |
| 276 | goto no_quota; |
| 277 | |
| 278 | user->qnkeys++; |
| 279 | user->qnbytes += quotalen; |
| 280 | spin_unlock(&user->lock); |
| 281 | } |
| 282 | |
| 283 | /* allocate and initialise the key and its description */ |
| 284 | key = kmem_cache_alloc(key_jar, SLAB_KERNEL); |
| 285 | if (!key) |
| 286 | goto no_memory_2; |
| 287 | |
| 288 | if (desc) { |
| 289 | key->description = kmalloc(desclen, GFP_KERNEL); |
| 290 | if (!key->description) |
| 291 | goto no_memory_3; |
| 292 | |
| 293 | memcpy(key->description, desc, desclen); |
| 294 | } |
| 295 | |
| 296 | atomic_set(&key->usage, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 297 | init_rwsem(&key->sem); |
| 298 | key->type = type; |
| 299 | key->user = user; |
| 300 | key->quotalen = quotalen; |
| 301 | key->datalen = type->def_datalen; |
| 302 | key->uid = uid; |
| 303 | key->gid = gid; |
| 304 | key->perm = perm; |
| 305 | key->flags = 0; |
| 306 | key->expiry = 0; |
| 307 | key->payload.data = NULL; |
| 308 | |
| 309 | if (!not_in_quota) |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 310 | key->flags |= 1 << KEY_FLAG_IN_QUOTA; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 311 | |
| 312 | memset(&key->type_data, 0, sizeof(key->type_data)); |
| 313 | |
| 314 | #ifdef KEY_DEBUGGING |
| 315 | key->magic = KEY_DEBUG_MAGIC; |
| 316 | #endif |
| 317 | |
| 318 | /* publish the key by giving it a serial number */ |
| 319 | atomic_inc(&user->nkeys); |
| 320 | key_alloc_serial(key); |
| 321 | |
| 322 | error: |
| 323 | return key; |
| 324 | |
| 325 | no_memory_3: |
| 326 | kmem_cache_free(key_jar, key); |
| 327 | no_memory_2: |
| 328 | if (!not_in_quota) { |
| 329 | spin_lock(&user->lock); |
| 330 | user->qnkeys--; |
| 331 | user->qnbytes -= quotalen; |
| 332 | spin_unlock(&user->lock); |
| 333 | } |
| 334 | key_user_put(user); |
| 335 | no_memory_1: |
| 336 | key = ERR_PTR(-ENOMEM); |
| 337 | goto error; |
| 338 | |
| 339 | no_quota: |
| 340 | spin_unlock(&user->lock); |
| 341 | key_user_put(user); |
| 342 | key = ERR_PTR(-EDQUOT); |
| 343 | goto error; |
| 344 | |
| 345 | } /* end key_alloc() */ |
| 346 | |
| 347 | EXPORT_SYMBOL(key_alloc); |
| 348 | |
| 349 | /*****************************************************************************/ |
| 350 | /* |
| 351 | * reserve an amount of quota for the key's payload |
| 352 | */ |
| 353 | int key_payload_reserve(struct key *key, size_t datalen) |
| 354 | { |
| 355 | int delta = (int) datalen - key->datalen; |
| 356 | int ret = 0; |
| 357 | |
| 358 | key_check(key); |
| 359 | |
| 360 | /* contemplate the quota adjustment */ |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 361 | if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 362 | spin_lock(&key->user->lock); |
| 363 | |
| 364 | if (delta > 0 && |
| 365 | key->user->qnbytes + delta > KEYQUOTA_MAX_BYTES |
| 366 | ) { |
| 367 | ret = -EDQUOT; |
| 368 | } |
| 369 | else { |
| 370 | key->user->qnbytes += delta; |
| 371 | key->quotalen += delta; |
| 372 | } |
| 373 | spin_unlock(&key->user->lock); |
| 374 | } |
| 375 | |
| 376 | /* change the recorded data length if that didn't generate an error */ |
| 377 | if (ret == 0) |
| 378 | key->datalen = datalen; |
| 379 | |
| 380 | return ret; |
| 381 | |
| 382 | } /* end key_payload_reserve() */ |
| 383 | |
| 384 | EXPORT_SYMBOL(key_payload_reserve); |
| 385 | |
| 386 | /*****************************************************************************/ |
| 387 | /* |
| 388 | * instantiate a key and link it into the target keyring atomically |
| 389 | * - called with the target keyring's semaphore writelocked |
| 390 | */ |
| 391 | static int __key_instantiate_and_link(struct key *key, |
| 392 | const void *data, |
| 393 | size_t datalen, |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 394 | struct key *keyring, |
| 395 | struct key *instkey) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 396 | { |
| 397 | int ret, awaken; |
| 398 | |
| 399 | key_check(key); |
| 400 | key_check(keyring); |
| 401 | |
| 402 | awaken = 0; |
| 403 | ret = -EBUSY; |
| 404 | |
| 405 | down_write(&key_construction_sem); |
| 406 | |
| 407 | /* can't instantiate twice */ |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 408 | if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 409 | /* instantiate the key */ |
| 410 | ret = key->type->instantiate(key, data, datalen); |
| 411 | |
| 412 | if (ret == 0) { |
| 413 | /* mark the key as being instantiated */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 414 | atomic_inc(&key->user->nikeys); |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 415 | set_bit(KEY_FLAG_INSTANTIATED, &key->flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 416 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 417 | if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 418 | awaken = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 419 | |
| 420 | /* and link it into the destination keyring */ |
| 421 | if (keyring) |
| 422 | ret = __key_link(keyring, key); |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 423 | |
| 424 | /* disable the authorisation key */ |
| 425 | if (instkey) |
| 426 | key_revoke(instkey); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 427 | } |
| 428 | } |
| 429 | |
| 430 | up_write(&key_construction_sem); |
| 431 | |
| 432 | /* wake up anyone waiting for a key to be constructed */ |
| 433 | if (awaken) |
| 434 | wake_up_all(&request_key_conswq); |
| 435 | |
| 436 | return ret; |
| 437 | |
| 438 | } /* end __key_instantiate_and_link() */ |
| 439 | |
| 440 | /*****************************************************************************/ |
| 441 | /* |
| 442 | * instantiate a key and link it into the target keyring atomically |
| 443 | */ |
| 444 | int key_instantiate_and_link(struct key *key, |
| 445 | const void *data, |
| 446 | size_t datalen, |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 447 | struct key *keyring, |
| 448 | struct key *instkey) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 449 | { |
| 450 | int ret; |
| 451 | |
| 452 | if (keyring) |
| 453 | down_write(&keyring->sem); |
| 454 | |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 455 | ret = __key_instantiate_and_link(key, data, datalen, keyring, instkey); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 456 | |
| 457 | if (keyring) |
| 458 | up_write(&keyring->sem); |
| 459 | |
| 460 | return ret; |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 461 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 462 | } /* end key_instantiate_and_link() */ |
| 463 | |
| 464 | EXPORT_SYMBOL(key_instantiate_and_link); |
| 465 | |
| 466 | /*****************************************************************************/ |
| 467 | /* |
| 468 | * negatively instantiate a key and link it into the target keyring atomically |
| 469 | */ |
| 470 | int key_negate_and_link(struct key *key, |
| 471 | unsigned timeout, |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 472 | struct key *keyring, |
| 473 | struct key *instkey) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 474 | { |
| 475 | struct timespec now; |
| 476 | int ret, awaken; |
| 477 | |
| 478 | key_check(key); |
| 479 | key_check(keyring); |
| 480 | |
| 481 | awaken = 0; |
| 482 | ret = -EBUSY; |
| 483 | |
| 484 | if (keyring) |
| 485 | down_write(&keyring->sem); |
| 486 | |
| 487 | down_write(&key_construction_sem); |
| 488 | |
| 489 | /* can't instantiate twice */ |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 490 | if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 491 | /* mark the key as being negatively instantiated */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 492 | atomic_inc(&key->user->nikeys); |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 493 | set_bit(KEY_FLAG_NEGATIVE, &key->flags); |
| 494 | set_bit(KEY_FLAG_INSTANTIATED, &key->flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 495 | now = current_kernel_time(); |
| 496 | key->expiry = now.tv_sec + timeout; |
| 497 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 498 | if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 499 | awaken = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 500 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 501 | ret = 0; |
| 502 | |
| 503 | /* and link it into the destination keyring */ |
| 504 | if (keyring) |
| 505 | ret = __key_link(keyring, key); |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 506 | |
| 507 | /* disable the authorisation key */ |
| 508 | if (instkey) |
| 509 | key_revoke(instkey); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 510 | } |
| 511 | |
| 512 | up_write(&key_construction_sem); |
| 513 | |
| 514 | if (keyring) |
| 515 | up_write(&keyring->sem); |
| 516 | |
| 517 | /* wake up anyone waiting for a key to be constructed */ |
| 518 | if (awaken) |
| 519 | wake_up_all(&request_key_conswq); |
| 520 | |
| 521 | return ret; |
| 522 | |
| 523 | } /* end key_negate_and_link() */ |
| 524 | |
| 525 | EXPORT_SYMBOL(key_negate_and_link); |
| 526 | |
| 527 | /*****************************************************************************/ |
| 528 | /* |
| 529 | * do cleaning up in process context so that we don't have to disable |
| 530 | * interrupts all over the place |
| 531 | */ |
| 532 | static void key_cleanup(void *data) |
| 533 | { |
| 534 | struct rb_node *_n; |
| 535 | struct key *key; |
| 536 | |
| 537 | go_again: |
| 538 | /* look for a dead key in the tree */ |
| 539 | spin_lock(&key_serial_lock); |
| 540 | |
| 541 | for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { |
| 542 | key = rb_entry(_n, struct key, serial_node); |
| 543 | |
| 544 | if (atomic_read(&key->usage) == 0) |
| 545 | goto found_dead_key; |
| 546 | } |
| 547 | |
| 548 | spin_unlock(&key_serial_lock); |
| 549 | return; |
| 550 | |
| 551 | found_dead_key: |
| 552 | /* we found a dead key - once we've removed it from the tree, we can |
| 553 | * drop the lock */ |
| 554 | rb_erase(&key->serial_node, &key_serial_tree); |
| 555 | spin_unlock(&key_serial_lock); |
| 556 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 557 | key_check(key); |
| 558 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 559 | /* deal with the user's key tracking and quota */ |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 560 | if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 561 | spin_lock(&key->user->lock); |
| 562 | key->user->qnkeys--; |
| 563 | key->user->qnbytes -= key->quotalen; |
| 564 | spin_unlock(&key->user->lock); |
| 565 | } |
| 566 | |
| 567 | atomic_dec(&key->user->nkeys); |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 568 | if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 569 | atomic_dec(&key->user->nikeys); |
| 570 | |
| 571 | key_user_put(key->user); |
| 572 | |
| 573 | /* now throw away the key memory */ |
| 574 | if (key->type->destroy) |
| 575 | key->type->destroy(key); |
| 576 | |
| 577 | kfree(key->description); |
| 578 | |
| 579 | #ifdef KEY_DEBUGGING |
| 580 | key->magic = KEY_DEBUG_MAGIC_X; |
| 581 | #endif |
| 582 | kmem_cache_free(key_jar, key); |
| 583 | |
| 584 | /* there may, of course, be more than one key to destroy */ |
| 585 | goto go_again; |
| 586 | |
| 587 | } /* end key_cleanup() */ |
| 588 | |
| 589 | /*****************************************************************************/ |
| 590 | /* |
| 591 | * dispose of a reference to a key |
| 592 | * - when all the references are gone, we schedule the cleanup task to come and |
| 593 | * pull it out of the tree in definite process context |
| 594 | */ |
| 595 | void key_put(struct key *key) |
| 596 | { |
| 597 | if (key) { |
| 598 | key_check(key); |
| 599 | |
| 600 | if (atomic_dec_and_test(&key->usage)) |
| 601 | schedule_work(&key_cleanup_task); |
| 602 | } |
| 603 | |
| 604 | } /* end key_put() */ |
| 605 | |
| 606 | EXPORT_SYMBOL(key_put); |
| 607 | |
| 608 | /*****************************************************************************/ |
| 609 | /* |
| 610 | * find a key by its serial number |
| 611 | */ |
| 612 | struct key *key_lookup(key_serial_t id) |
| 613 | { |
| 614 | struct rb_node *n; |
| 615 | struct key *key; |
| 616 | |
| 617 | spin_lock(&key_serial_lock); |
| 618 | |
| 619 | /* search the tree for the specified key */ |
| 620 | n = key_serial_tree.rb_node; |
| 621 | while (n) { |
| 622 | key = rb_entry(n, struct key, serial_node); |
| 623 | |
| 624 | if (id < key->serial) |
| 625 | n = n->rb_left; |
| 626 | else if (id > key->serial) |
| 627 | n = n->rb_right; |
| 628 | else |
| 629 | goto found; |
| 630 | } |
| 631 | |
| 632 | not_found: |
| 633 | key = ERR_PTR(-ENOKEY); |
| 634 | goto error; |
| 635 | |
| 636 | found: |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 637 | /* pretend it doesn't exist if it's dead */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 638 | if (atomic_read(&key->usage) == 0 || |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 639 | test_bit(KEY_FLAG_DEAD, &key->flags) || |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 640 | key->type == &key_type_dead) |
| 641 | goto not_found; |
| 642 | |
| 643 | /* this races with key_put(), but that doesn't matter since key_put() |
| 644 | * doesn't actually change the key |
| 645 | */ |
| 646 | atomic_inc(&key->usage); |
| 647 | |
| 648 | error: |
| 649 | spin_unlock(&key_serial_lock); |
| 650 | return key; |
| 651 | |
| 652 | } /* end key_lookup() */ |
| 653 | |
| 654 | /*****************************************************************************/ |
| 655 | /* |
| 656 | * find and lock the specified key type against removal |
| 657 | * - we return with the sem readlocked |
| 658 | */ |
| 659 | struct key_type *key_type_lookup(const char *type) |
| 660 | { |
| 661 | struct key_type *ktype; |
| 662 | |
| 663 | down_read(&key_types_sem); |
| 664 | |
| 665 | /* look up the key type to see if it's one of the registered kernel |
| 666 | * types */ |
| 667 | list_for_each_entry(ktype, &key_types_list, link) { |
| 668 | if (strcmp(ktype->name, type) == 0) |
| 669 | goto found_kernel_type; |
| 670 | } |
| 671 | |
| 672 | up_read(&key_types_sem); |
| 673 | ktype = ERR_PTR(-ENOKEY); |
| 674 | |
| 675 | found_kernel_type: |
| 676 | return ktype; |
| 677 | |
| 678 | } /* end key_type_lookup() */ |
| 679 | |
| 680 | /*****************************************************************************/ |
| 681 | /* |
| 682 | * unlock a key type |
| 683 | */ |
| 684 | void key_type_put(struct key_type *ktype) |
| 685 | { |
| 686 | up_read(&key_types_sem); |
| 687 | |
| 688 | } /* end key_type_put() */ |
| 689 | |
| 690 | /*****************************************************************************/ |
| 691 | /* |
| 692 | * attempt to update an existing key |
| 693 | * - the key has an incremented refcount |
| 694 | * - we need to put the key if we get an error |
| 695 | */ |
| 696 | static inline struct key *__key_update(struct key *key, const void *payload, |
| 697 | size_t plen) |
| 698 | { |
| 699 | int ret; |
| 700 | |
| 701 | /* need write permission on the key to update it */ |
| 702 | ret = -EACCES; |
| 703 | if (!key_permission(key, KEY_WRITE)) |
| 704 | goto error; |
| 705 | |
| 706 | ret = -EEXIST; |
| 707 | if (!key->type->update) |
| 708 | goto error; |
| 709 | |
| 710 | down_write(&key->sem); |
| 711 | |
| 712 | ret = key->type->update(key, payload, plen); |
| 713 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 714 | if (ret == 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 715 | /* updating a negative key instantiates it */ |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 716 | clear_bit(KEY_FLAG_NEGATIVE, &key->flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 717 | |
| 718 | up_write(&key->sem); |
| 719 | |
| 720 | if (ret < 0) |
| 721 | goto error; |
| 722 | out: |
| 723 | return key; |
| 724 | |
| 725 | error: |
| 726 | key_put(key); |
| 727 | key = ERR_PTR(ret); |
| 728 | goto out; |
| 729 | |
| 730 | } /* end __key_update() */ |
| 731 | |
| 732 | /*****************************************************************************/ |
| 733 | /* |
| 734 | * search the specified keyring for a key of the same description; if one is |
| 735 | * found, update it, otherwise add a new one |
| 736 | */ |
| 737 | struct key *key_create_or_update(struct key *keyring, |
| 738 | const char *type, |
| 739 | const char *description, |
| 740 | const void *payload, |
| 741 | size_t plen, |
| 742 | int not_in_quota) |
| 743 | { |
| 744 | struct key_type *ktype; |
| 745 | struct key *key = NULL; |
| 746 | key_perm_t perm; |
| 747 | int ret; |
| 748 | |
| 749 | key_check(keyring); |
| 750 | |
| 751 | /* look up the key type to see if it's one of the registered kernel |
| 752 | * types */ |
| 753 | ktype = key_type_lookup(type); |
| 754 | if (IS_ERR(ktype)) { |
| 755 | key = ERR_PTR(-ENODEV); |
| 756 | goto error; |
| 757 | } |
| 758 | |
| 759 | ret = -EINVAL; |
| 760 | if (!ktype->match || !ktype->instantiate) |
| 761 | goto error_2; |
| 762 | |
| 763 | /* search for an existing key of the same type and description in the |
| 764 | * destination keyring |
| 765 | */ |
| 766 | down_write(&keyring->sem); |
| 767 | |
| 768 | key = __keyring_search_one(keyring, ktype, description, 0); |
| 769 | if (!IS_ERR(key)) |
| 770 | goto found_matching_key; |
| 771 | |
| 772 | /* if we're going to allocate a new key, we're going to have to modify |
| 773 | * the keyring */ |
| 774 | ret = -EACCES; |
| 775 | if (!key_permission(keyring, KEY_WRITE)) |
| 776 | goto error_3; |
| 777 | |
| 778 | /* decide on the permissions we want */ |
| 779 | perm = KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK; |
| 780 | |
| 781 | if (ktype->read) |
| 782 | perm |= KEY_USR_READ; |
| 783 | |
| 784 | if (ktype == &key_type_keyring || ktype->update) |
| 785 | perm |= KEY_USR_WRITE; |
| 786 | |
| 787 | /* allocate a new key */ |
| 788 | key = key_alloc(ktype, description, current->fsuid, current->fsgid, |
| 789 | perm, not_in_quota); |
| 790 | if (IS_ERR(key)) { |
| 791 | ret = PTR_ERR(key); |
| 792 | goto error_3; |
| 793 | } |
| 794 | |
| 795 | /* instantiate it and link it into the target keyring */ |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 796 | ret = __key_instantiate_and_link(key, payload, plen, keyring, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 797 | if (ret < 0) { |
| 798 | key_put(key); |
| 799 | key = ERR_PTR(ret); |
| 800 | } |
| 801 | |
| 802 | error_3: |
| 803 | up_write(&keyring->sem); |
| 804 | error_2: |
| 805 | key_type_put(ktype); |
| 806 | error: |
| 807 | return key; |
| 808 | |
| 809 | found_matching_key: |
| 810 | /* we found a matching key, so we're going to try to update it |
| 811 | * - we can drop the locks first as we have the key pinned |
| 812 | */ |
| 813 | up_write(&keyring->sem); |
| 814 | key_type_put(ktype); |
| 815 | |
| 816 | key = __key_update(key, payload, plen); |
| 817 | goto error; |
| 818 | |
| 819 | } /* end key_create_or_update() */ |
| 820 | |
| 821 | EXPORT_SYMBOL(key_create_or_update); |
| 822 | |
| 823 | /*****************************************************************************/ |
| 824 | /* |
| 825 | * update a key |
| 826 | */ |
| 827 | int key_update(struct key *key, const void *payload, size_t plen) |
| 828 | { |
| 829 | int ret; |
| 830 | |
| 831 | key_check(key); |
| 832 | |
| 833 | /* the key must be writable */ |
| 834 | ret = -EACCES; |
| 835 | if (!key_permission(key, KEY_WRITE)) |
| 836 | goto error; |
| 837 | |
| 838 | /* attempt to update it if supported */ |
| 839 | ret = -EOPNOTSUPP; |
| 840 | if (key->type->update) { |
| 841 | down_write(&key->sem); |
| 842 | ret = key->type->update(key, payload, plen); |
| 843 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 844 | if (ret == 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 845 | /* updating a negative key instantiates it */ |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 846 | clear_bit(KEY_FLAG_NEGATIVE, &key->flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 847 | |
| 848 | up_write(&key->sem); |
| 849 | } |
| 850 | |
| 851 | error: |
| 852 | return ret; |
| 853 | |
| 854 | } /* end key_update() */ |
| 855 | |
| 856 | EXPORT_SYMBOL(key_update); |
| 857 | |
| 858 | /*****************************************************************************/ |
| 859 | /* |
| 860 | * duplicate a key, potentially with a revised description |
| 861 | * - must be supported by the keytype (keyrings for instance can be duplicated) |
| 862 | */ |
| 863 | struct key *key_duplicate(struct key *source, const char *desc) |
| 864 | { |
| 865 | struct key *key; |
| 866 | int ret; |
| 867 | |
| 868 | key_check(source); |
| 869 | |
| 870 | if (!desc) |
| 871 | desc = source->description; |
| 872 | |
| 873 | down_read(&key_types_sem); |
| 874 | |
| 875 | ret = -EINVAL; |
| 876 | if (!source->type->duplicate) |
| 877 | goto error; |
| 878 | |
| 879 | /* allocate and instantiate a key */ |
| 880 | key = key_alloc(source->type, desc, current->fsuid, current->fsgid, |
| 881 | source->perm, 0); |
| 882 | if (IS_ERR(key)) |
| 883 | goto error_k; |
| 884 | |
| 885 | down_read(&source->sem); |
| 886 | ret = key->type->duplicate(key, source); |
| 887 | up_read(&source->sem); |
| 888 | if (ret < 0) |
| 889 | goto error2; |
| 890 | |
| 891 | atomic_inc(&key->user->nikeys); |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 892 | set_bit(KEY_FLAG_INSTANTIATED, &key->flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 893 | |
| 894 | error_k: |
| 895 | up_read(&key_types_sem); |
| 896 | out: |
| 897 | return key; |
| 898 | |
| 899 | error2: |
| 900 | key_put(key); |
| 901 | error: |
| 902 | up_read(&key_types_sem); |
| 903 | key = ERR_PTR(ret); |
| 904 | goto out; |
| 905 | |
| 906 | } /* end key_duplicate() */ |
| 907 | |
| 908 | /*****************************************************************************/ |
| 909 | /* |
| 910 | * revoke a key |
| 911 | */ |
| 912 | void key_revoke(struct key *key) |
| 913 | { |
| 914 | key_check(key); |
| 915 | |
| 916 | /* make sure no one's trying to change or use the key when we mark |
| 917 | * it */ |
| 918 | down_write(&key->sem); |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 919 | set_bit(KEY_FLAG_REVOKED, &key->flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 920 | up_write(&key->sem); |
| 921 | |
| 922 | } /* end key_revoke() */ |
| 923 | |
| 924 | EXPORT_SYMBOL(key_revoke); |
| 925 | |
| 926 | /*****************************************************************************/ |
| 927 | /* |
| 928 | * register a type of key |
| 929 | */ |
| 930 | int register_key_type(struct key_type *ktype) |
| 931 | { |
| 932 | struct key_type *p; |
| 933 | int ret; |
| 934 | |
| 935 | ret = -EEXIST; |
| 936 | down_write(&key_types_sem); |
| 937 | |
| 938 | /* disallow key types with the same name */ |
| 939 | list_for_each_entry(p, &key_types_list, link) { |
| 940 | if (strcmp(p->name, ktype->name) == 0) |
| 941 | goto out; |
| 942 | } |
| 943 | |
| 944 | /* store the type */ |
| 945 | list_add(&ktype->link, &key_types_list); |
| 946 | ret = 0; |
| 947 | |
| 948 | out: |
| 949 | up_write(&key_types_sem); |
| 950 | return ret; |
| 951 | |
| 952 | } /* end register_key_type() */ |
| 953 | |
| 954 | EXPORT_SYMBOL(register_key_type); |
| 955 | |
| 956 | /*****************************************************************************/ |
| 957 | /* |
| 958 | * unregister a type of key |
| 959 | */ |
| 960 | void unregister_key_type(struct key_type *ktype) |
| 961 | { |
| 962 | struct rb_node *_n; |
| 963 | struct key *key; |
| 964 | |
| 965 | down_write(&key_types_sem); |
| 966 | |
| 967 | /* withdraw the key type */ |
| 968 | list_del_init(&ktype->link); |
| 969 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 970 | /* mark all the keys of this type dead */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 971 | spin_lock(&key_serial_lock); |
| 972 | |
| 973 | for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { |
| 974 | key = rb_entry(_n, struct key, serial_node); |
| 975 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 976 | if (key->type == ktype) |
| 977 | key->type = &key_type_dead; |
| 978 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 979 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 980 | spin_unlock(&key_serial_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 981 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 982 | /* make sure everyone revalidates their keys */ |
Paul E. McKenney | b2b1866 | 2005-06-25 14:55:38 -0700 | [diff] [blame^] | 983 | synchronize_rcu(); |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 984 | |
| 985 | /* we should now be able to destroy the payloads of all the keys of |
| 986 | * this type with impunity */ |
| 987 | spin_lock(&key_serial_lock); |
| 988 | |
| 989 | for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { |
| 990 | key = rb_entry(_n, struct key, serial_node); |
| 991 | |
| 992 | if (key->type == ktype) { |
| 993 | if (ktype->destroy) |
| 994 | ktype->destroy(key); |
| 995 | memset(&key->payload, 0xbd, sizeof(key->payload)); |
| 996 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 997 | } |
| 998 | |
| 999 | spin_unlock(&key_serial_lock); |
| 1000 | up_write(&key_types_sem); |
| 1001 | |
| 1002 | } /* end unregister_key_type() */ |
| 1003 | |
| 1004 | EXPORT_SYMBOL(unregister_key_type); |
| 1005 | |
| 1006 | /*****************************************************************************/ |
| 1007 | /* |
| 1008 | * initialise the key management stuff |
| 1009 | */ |
| 1010 | void __init key_init(void) |
| 1011 | { |
| 1012 | /* allocate a slab in which we can store keys */ |
| 1013 | key_jar = kmem_cache_create("key_jar", sizeof(struct key), |
| 1014 | 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); |
| 1015 | |
| 1016 | /* add the special key types */ |
| 1017 | list_add_tail(&key_type_keyring.link, &key_types_list); |
| 1018 | list_add_tail(&key_type_dead.link, &key_types_list); |
| 1019 | list_add_tail(&key_type_user.link, &key_types_list); |
| 1020 | |
| 1021 | /* record the root user tracking */ |
| 1022 | rb_link_node(&root_key_user.node, |
| 1023 | NULL, |
| 1024 | &key_user_tree.rb_node); |
| 1025 | |
| 1026 | rb_insert_color(&root_key_user.node, |
| 1027 | &key_user_tree); |
| 1028 | |
| 1029 | /* record root's user standard keyrings */ |
| 1030 | key_check(&root_user_keyring); |
| 1031 | key_check(&root_session_keyring); |
| 1032 | |
| 1033 | __key_insert_serial(&root_user_keyring); |
| 1034 | __key_insert_serial(&root_session_keyring); |
| 1035 | |
| 1036 | keyring_publish_name(&root_user_keyring); |
| 1037 | keyring_publish_name(&root_session_keyring); |
| 1038 | |
| 1039 | /* link the two root keyrings together */ |
| 1040 | key_link(&root_session_keyring, &root_user_keyring); |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 1041 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1042 | } /* end key_init() */ |