Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* keyring.c: keyring handling |
| 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> |
David Howells | 29db919 | 2005-10-30 15:02:44 -0800 | [diff] [blame] | 16 | #include <linux/security.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | #include <linux/seq_file.h> |
| 18 | #include <linux/err.h> |
| 19 | #include <asm/uaccess.h> |
| 20 | #include "internal.h" |
| 21 | |
| 22 | /* |
| 23 | * when plumbing the depths of the key tree, this sets a hard limit set on how |
| 24 | * deep we're willing to go |
| 25 | */ |
| 26 | #define KEYRING_SEARCH_MAX_DEPTH 6 |
| 27 | |
| 28 | /* |
| 29 | * we keep all named keyrings in a hash to speed looking them up |
| 30 | */ |
| 31 | #define KEYRING_NAME_HASH_SIZE (1 << 5) |
| 32 | |
| 33 | static struct list_head keyring_name_hash[KEYRING_NAME_HASH_SIZE]; |
| 34 | static DEFINE_RWLOCK(keyring_name_lock); |
| 35 | |
| 36 | static inline unsigned keyring_hash(const char *desc) |
| 37 | { |
| 38 | unsigned bucket = 0; |
| 39 | |
| 40 | for (; *desc; desc++) |
| 41 | bucket += (unsigned char) *desc; |
| 42 | |
| 43 | return bucket & (KEYRING_NAME_HASH_SIZE - 1); |
| 44 | } |
| 45 | |
| 46 | /* |
| 47 | * the keyring type definition |
| 48 | */ |
| 49 | static int keyring_instantiate(struct key *keyring, |
| 50 | const void *data, size_t datalen); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 51 | static int keyring_match(const struct key *keyring, const void *criterion); |
David Howells | 31204ed | 2006-06-26 00:24:51 -0700 | [diff] [blame] | 52 | static void keyring_revoke(struct key *keyring); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 53 | static void keyring_destroy(struct key *keyring); |
| 54 | static void keyring_describe(const struct key *keyring, struct seq_file *m); |
| 55 | static long keyring_read(const struct key *keyring, |
| 56 | char __user *buffer, size_t buflen); |
| 57 | |
| 58 | struct key_type key_type_keyring = { |
| 59 | .name = "keyring", |
| 60 | .def_datalen = sizeof(struct keyring_list), |
| 61 | .instantiate = keyring_instantiate, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 62 | .match = keyring_match, |
David Howells | 31204ed | 2006-06-26 00:24:51 -0700 | [diff] [blame] | 63 | .revoke = keyring_revoke, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 64 | .destroy = keyring_destroy, |
| 65 | .describe = keyring_describe, |
| 66 | .read = keyring_read, |
| 67 | }; |
| 68 | |
| 69 | /* |
| 70 | * semaphore to serialise link/link calls to prevent two link calls in parallel |
| 71 | * introducing a cycle |
| 72 | */ |
Adrian Bunk | 1ae8f40 | 2006-01-06 00:11:25 -0800 | [diff] [blame] | 73 | static DECLARE_RWSEM(keyring_serialise_link_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | |
| 75 | /*****************************************************************************/ |
| 76 | /* |
| 77 | * publish the name of a keyring so that it can be found by name (if it has |
| 78 | * one) |
| 79 | */ |
| 80 | void keyring_publish_name(struct key *keyring) |
| 81 | { |
| 82 | int bucket; |
| 83 | |
| 84 | if (keyring->description) { |
| 85 | bucket = keyring_hash(keyring->description); |
| 86 | |
| 87 | write_lock(&keyring_name_lock); |
| 88 | |
| 89 | if (!keyring_name_hash[bucket].next) |
| 90 | INIT_LIST_HEAD(&keyring_name_hash[bucket]); |
| 91 | |
| 92 | list_add_tail(&keyring->type_data.link, |
| 93 | &keyring_name_hash[bucket]); |
| 94 | |
| 95 | write_unlock(&keyring_name_lock); |
| 96 | } |
| 97 | |
| 98 | } /* end keyring_publish_name() */ |
| 99 | |
| 100 | /*****************************************************************************/ |
| 101 | /* |
| 102 | * initialise a keyring |
| 103 | * - we object if we were given any data |
| 104 | */ |
| 105 | static int keyring_instantiate(struct key *keyring, |
| 106 | const void *data, size_t datalen) |
| 107 | { |
| 108 | int ret; |
| 109 | |
| 110 | ret = -EINVAL; |
| 111 | if (datalen == 0) { |
| 112 | /* make the keyring available by name if it has one */ |
| 113 | keyring_publish_name(keyring); |
| 114 | ret = 0; |
| 115 | } |
| 116 | |
| 117 | return ret; |
| 118 | |
| 119 | } /* end keyring_instantiate() */ |
| 120 | |
| 121 | /*****************************************************************************/ |
| 122 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 123 | * match keyrings on their name |
| 124 | */ |
| 125 | static int keyring_match(const struct key *keyring, const void *description) |
| 126 | { |
| 127 | return keyring->description && |
| 128 | strcmp(keyring->description, description) == 0; |
| 129 | |
| 130 | } /* end keyring_match() */ |
| 131 | |
| 132 | /*****************************************************************************/ |
| 133 | /* |
| 134 | * dispose of the data dangling from the corpse of a keyring |
| 135 | */ |
| 136 | static void keyring_destroy(struct key *keyring) |
| 137 | { |
| 138 | struct keyring_list *klist; |
| 139 | int loop; |
| 140 | |
| 141 | if (keyring->description) { |
| 142 | write_lock(&keyring_name_lock); |
David Howells | 94efe72 | 2005-08-04 13:07:07 -0700 | [diff] [blame] | 143 | |
| 144 | if (keyring->type_data.link.next != NULL && |
| 145 | !list_empty(&keyring->type_data.link)) |
| 146 | list_del(&keyring->type_data.link); |
| 147 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 148 | write_unlock(&keyring_name_lock); |
| 149 | } |
| 150 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 151 | klist = rcu_dereference(keyring->payload.subscriptions); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 152 | if (klist) { |
| 153 | for (loop = klist->nkeys - 1; loop >= 0; loop--) |
| 154 | key_put(klist->keys[loop]); |
| 155 | kfree(klist); |
| 156 | } |
| 157 | |
| 158 | } /* end keyring_destroy() */ |
| 159 | |
| 160 | /*****************************************************************************/ |
| 161 | /* |
| 162 | * describe the keyring |
| 163 | */ |
| 164 | static void keyring_describe(const struct key *keyring, struct seq_file *m) |
| 165 | { |
| 166 | struct keyring_list *klist; |
| 167 | |
| 168 | if (keyring->description) { |
| 169 | seq_puts(m, keyring->description); |
| 170 | } |
| 171 | else { |
| 172 | seq_puts(m, "[anon]"); |
| 173 | } |
| 174 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 175 | rcu_read_lock(); |
| 176 | klist = rcu_dereference(keyring->payload.subscriptions); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | if (klist) |
| 178 | seq_printf(m, ": %u/%u", klist->nkeys, klist->maxkeys); |
| 179 | else |
| 180 | seq_puts(m, ": empty"); |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 181 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 182 | |
| 183 | } /* end keyring_describe() */ |
| 184 | |
| 185 | /*****************************************************************************/ |
| 186 | /* |
| 187 | * read a list of key IDs from the keyring's contents |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 188 | * - the keyring's semaphore is read-locked |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 189 | */ |
| 190 | static long keyring_read(const struct key *keyring, |
| 191 | char __user *buffer, size_t buflen) |
| 192 | { |
| 193 | struct keyring_list *klist; |
| 194 | struct key *key; |
| 195 | size_t qty, tmp; |
| 196 | int loop, ret; |
| 197 | |
| 198 | ret = 0; |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 199 | klist = rcu_dereference(keyring->payload.subscriptions); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 200 | |
| 201 | if (klist) { |
| 202 | /* calculate how much data we could return */ |
| 203 | qty = klist->nkeys * sizeof(key_serial_t); |
| 204 | |
| 205 | if (buffer && buflen > 0) { |
| 206 | if (buflen > qty) |
| 207 | buflen = qty; |
| 208 | |
| 209 | /* copy the IDs of the subscribed keys into the |
| 210 | * buffer */ |
| 211 | ret = -EFAULT; |
| 212 | |
| 213 | for (loop = 0; loop < klist->nkeys; loop++) { |
| 214 | key = klist->keys[loop]; |
| 215 | |
| 216 | tmp = sizeof(key_serial_t); |
| 217 | if (tmp > buflen) |
| 218 | tmp = buflen; |
| 219 | |
| 220 | if (copy_to_user(buffer, |
| 221 | &key->serial, |
| 222 | tmp) != 0) |
| 223 | goto error; |
| 224 | |
| 225 | buflen -= tmp; |
| 226 | if (buflen == 0) |
| 227 | break; |
| 228 | buffer += tmp; |
| 229 | } |
| 230 | } |
| 231 | |
| 232 | ret = qty; |
| 233 | } |
| 234 | |
| 235 | error: |
| 236 | return ret; |
| 237 | |
| 238 | } /* end keyring_read() */ |
| 239 | |
| 240 | /*****************************************************************************/ |
| 241 | /* |
| 242 | * allocate a keyring and link into the destination keyring |
| 243 | */ |
| 244 | struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid, |
David Howells | 7e047ef | 2006-06-26 00:24:50 -0700 | [diff] [blame] | 245 | struct task_struct *ctx, unsigned long flags, |
Michael LeMay | d720024 | 2006-06-22 14:47:17 -0700 | [diff] [blame] | 246 | struct key *dest) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 247 | { |
| 248 | struct key *keyring; |
| 249 | int ret; |
| 250 | |
| 251 | keyring = key_alloc(&key_type_keyring, description, |
Michael LeMay | d720024 | 2006-06-22 14:47:17 -0700 | [diff] [blame] | 252 | uid, gid, ctx, |
David Howells | 29db919 | 2005-10-30 15:02:44 -0800 | [diff] [blame] | 253 | (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL, |
David Howells | 7e047ef | 2006-06-26 00:24:50 -0700 | [diff] [blame] | 254 | flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 255 | |
| 256 | if (!IS_ERR(keyring)) { |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 257 | ret = key_instantiate_and_link(keyring, NULL, 0, dest, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | if (ret < 0) { |
| 259 | key_put(keyring); |
| 260 | keyring = ERR_PTR(ret); |
| 261 | } |
| 262 | } |
| 263 | |
| 264 | return keyring; |
| 265 | |
| 266 | } /* end keyring_alloc() */ |
| 267 | |
| 268 | /*****************************************************************************/ |
| 269 | /* |
| 270 | * search the supplied keyring tree for a key that matches the criterion |
| 271 | * - perform a breadth-then-depth search up to the prescribed limit |
| 272 | * - we only find keys on which we have search permission |
| 273 | * - we use the supplied match function to see if the description (or other |
| 274 | * feature of interest) matches |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 275 | * - we rely on RCU to prevent the keyring lists from disappearing on us |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 276 | * - we return -EAGAIN if we didn't find any matching key |
| 277 | * - we return -ENOKEY if we only found negative matching keys |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 278 | * - we propagate the possession attribute from the keyring ref to the key ref |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 279 | */ |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 280 | key_ref_t keyring_search_aux(key_ref_t keyring_ref, |
| 281 | struct task_struct *context, |
| 282 | struct key_type *type, |
| 283 | const void *description, |
| 284 | key_match_func_t match) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 285 | { |
| 286 | struct { |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 287 | struct keyring_list *keylist; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 288 | int kix; |
| 289 | } stack[KEYRING_SEARCH_MAX_DEPTH]; |
| 290 | |
| 291 | struct keyring_list *keylist; |
| 292 | struct timespec now; |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 293 | unsigned long possessed; |
| 294 | struct key *keyring, *key; |
| 295 | key_ref_t key_ref; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 296 | long err; |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 297 | int sp, kix; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 298 | |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 299 | keyring = key_ref_to_ptr(keyring_ref); |
| 300 | possessed = is_key_possessed(keyring_ref); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 301 | key_check(keyring); |
| 302 | |
| 303 | /* top keyring must have search permission to begin the search */ |
David Howells | 29db919 | 2005-10-30 15:02:44 -0800 | [diff] [blame] | 304 | err = key_task_permission(keyring_ref, context, KEY_SEARCH); |
| 305 | if (err < 0) { |
| 306 | key_ref = ERR_PTR(err); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 307 | goto error; |
David Howells | 29db919 | 2005-10-30 15:02:44 -0800 | [diff] [blame] | 308 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 309 | |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 310 | key_ref = ERR_PTR(-ENOTDIR); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 311 | if (keyring->type != &key_type_keyring) |
| 312 | goto error; |
| 313 | |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 314 | rcu_read_lock(); |
| 315 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 316 | now = current_kernel_time(); |
| 317 | err = -EAGAIN; |
| 318 | sp = 0; |
| 319 | |
| 320 | /* start processing a new keyring */ |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 321 | descend: |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 322 | if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 323 | goto not_this_keyring; |
| 324 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 325 | keylist = rcu_dereference(keyring->payload.subscriptions); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 326 | if (!keylist) |
| 327 | goto not_this_keyring; |
| 328 | |
| 329 | /* iterate through the keys in this keyring first */ |
| 330 | for (kix = 0; kix < keylist->nkeys; kix++) { |
| 331 | key = keylist->keys[kix]; |
| 332 | |
| 333 | /* ignore keys not of this type */ |
| 334 | if (key->type != type) |
| 335 | continue; |
| 336 | |
| 337 | /* skip revoked keys and expired keys */ |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 338 | if (test_bit(KEY_FLAG_REVOKED, &key->flags)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 339 | continue; |
| 340 | |
| 341 | if (key->expiry && now.tv_sec >= key->expiry) |
| 342 | continue; |
| 343 | |
| 344 | /* keys that don't match */ |
| 345 | if (!match(key, description)) |
| 346 | continue; |
| 347 | |
| 348 | /* key must have search permissions */ |
David Howells | 29db919 | 2005-10-30 15:02:44 -0800 | [diff] [blame] | 349 | if (key_task_permission(make_key_ref(key, possessed), |
| 350 | context, KEY_SEARCH) < 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 351 | continue; |
| 352 | |
| 353 | /* we set a different error code if we find a negative key */ |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 354 | if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 355 | err = -ENOKEY; |
| 356 | continue; |
| 357 | } |
| 358 | |
| 359 | goto found; |
| 360 | } |
| 361 | |
| 362 | /* search through the keyrings nested in this one */ |
| 363 | kix = 0; |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 364 | ascend: |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 365 | for (; kix < keylist->nkeys; kix++) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 366 | key = keylist->keys[kix]; |
| 367 | if (key->type != &key_type_keyring) |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 368 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 369 | |
| 370 | /* recursively search nested keyrings |
| 371 | * - only search keyrings for which we have search permission |
| 372 | */ |
| 373 | if (sp >= KEYRING_SEARCH_MAX_DEPTH) |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 374 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 375 | |
David Howells | 0f6ed7c | 2005-11-07 00:59:30 -0800 | [diff] [blame] | 376 | if (key_task_permission(make_key_ref(key, possessed), |
| 377 | context, KEY_SEARCH) < 0) |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 378 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 379 | |
| 380 | /* stack the current position */ |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 381 | stack[sp].keylist = keylist; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 382 | stack[sp].kix = kix; |
| 383 | sp++; |
| 384 | |
| 385 | /* begin again with the new keyring */ |
| 386 | keyring = key; |
| 387 | goto descend; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 388 | } |
| 389 | |
| 390 | /* the keyring we're looking at was disqualified or didn't contain a |
| 391 | * matching key */ |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 392 | not_this_keyring: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 393 | if (sp > 0) { |
| 394 | /* resume the processing of a keyring higher up in the tree */ |
| 395 | sp--; |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 396 | keylist = stack[sp].keylist; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 397 | kix = stack[sp].kix + 1; |
| 398 | goto ascend; |
| 399 | } |
| 400 | |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 401 | key_ref = ERR_PTR(err); |
| 402 | goto error_2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 403 | |
| 404 | /* we found a viable match */ |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 405 | found: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 406 | atomic_inc(&key->usage); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 407 | key_check(key); |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 408 | key_ref = make_key_ref(key, possessed); |
| 409 | error_2: |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 410 | rcu_read_unlock(); |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 411 | error: |
| 412 | return key_ref; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 413 | |
| 414 | } /* end keyring_search_aux() */ |
| 415 | |
| 416 | /*****************************************************************************/ |
| 417 | /* |
| 418 | * search the supplied keyring tree for a key that matches the criterion |
| 419 | * - perform a breadth-then-depth search up to the prescribed limit |
| 420 | * - we only find keys on which we have search permission |
| 421 | * - we readlock the keyrings as we search down the tree |
| 422 | * - we return -EAGAIN if we didn't find any matching key |
| 423 | * - we return -ENOKEY if we only found negative matching keys |
| 424 | */ |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 425 | key_ref_t keyring_search(key_ref_t keyring, |
| 426 | struct key_type *type, |
| 427 | const char *description) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 428 | { |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 429 | if (!type->match) |
| 430 | return ERR_PTR(-ENOKEY); |
| 431 | |
| 432 | return keyring_search_aux(keyring, current, |
| 433 | type, description, type->match); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 434 | |
| 435 | } /* end keyring_search() */ |
| 436 | |
| 437 | EXPORT_SYMBOL(keyring_search); |
| 438 | |
| 439 | /*****************************************************************************/ |
| 440 | /* |
| 441 | * search the given keyring only (no recursion) |
| 442 | * - keyring must be locked by caller |
David Howells | c3a9d65 | 2006-04-10 15:15:21 +0100 | [diff] [blame] | 443 | * - caller must guarantee that the keyring is a keyring |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 444 | */ |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 445 | key_ref_t __keyring_search_one(key_ref_t keyring_ref, |
| 446 | const struct key_type *ktype, |
| 447 | const char *description, |
| 448 | key_perm_t perm) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 449 | { |
| 450 | struct keyring_list *klist; |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 451 | unsigned long possessed; |
| 452 | struct key *keyring, *key; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 453 | int loop; |
| 454 | |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 455 | keyring = key_ref_to_ptr(keyring_ref); |
| 456 | possessed = is_key_possessed(keyring_ref); |
| 457 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 458 | rcu_read_lock(); |
| 459 | |
| 460 | klist = rcu_dereference(keyring->payload.subscriptions); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 461 | if (klist) { |
| 462 | for (loop = 0; loop < klist->nkeys; loop++) { |
| 463 | key = klist->keys[loop]; |
| 464 | |
| 465 | if (key->type == ktype && |
David Howells | 3e30148 | 2005-06-23 22:00:56 -0700 | [diff] [blame] | 466 | (!key->type->match || |
| 467 | key->type->match(key, description)) && |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 468 | key_permission(make_key_ref(key, possessed), |
David Howells | db1d1d5 | 2005-12-01 00:51:18 -0800 | [diff] [blame] | 469 | perm) == 0 && |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 470 | !test_bit(KEY_FLAG_REVOKED, &key->flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 471 | ) |
| 472 | goto found; |
| 473 | } |
| 474 | } |
| 475 | |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 476 | rcu_read_unlock(); |
| 477 | return ERR_PTR(-ENOKEY); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 478 | |
| 479 | found: |
| 480 | atomic_inc(&key->usage); |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 481 | rcu_read_unlock(); |
David Howells | 664cceb | 2005-09-28 17:03:15 +0100 | [diff] [blame] | 482 | return make_key_ref(key, possessed); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 483 | |
| 484 | } /* end __keyring_search_one() */ |
| 485 | |
| 486 | /*****************************************************************************/ |
| 487 | /* |
| 488 | * find a keyring with the specified name |
| 489 | * - all named keyrings are searched |
| 490 | * - only find keyrings with search permission for the process |
| 491 | * - only find keyrings with a serial number greater than the one specified |
| 492 | */ |
| 493 | struct key *find_keyring_by_name(const char *name, key_serial_t bound) |
| 494 | { |
| 495 | struct key *keyring; |
| 496 | int bucket; |
| 497 | |
| 498 | keyring = ERR_PTR(-EINVAL); |
| 499 | if (!name) |
| 500 | goto error; |
| 501 | |
| 502 | bucket = keyring_hash(name); |
| 503 | |
| 504 | read_lock(&keyring_name_lock); |
| 505 | |
| 506 | if (keyring_name_hash[bucket].next) { |
| 507 | /* search this hash bucket for a keyring with a matching name |
| 508 | * that's readable and that hasn't been revoked */ |
| 509 | list_for_each_entry(keyring, |
| 510 | &keyring_name_hash[bucket], |
| 511 | type_data.link |
| 512 | ) { |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 513 | if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 514 | continue; |
| 515 | |
| 516 | if (strcmp(keyring->description, name) != 0) |
| 517 | continue; |
| 518 | |
David Howells | 0f6ed7c | 2005-11-07 00:59:30 -0800 | [diff] [blame] | 519 | if (key_permission(make_key_ref(keyring, 0), |
| 520 | KEY_SEARCH) < 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 521 | continue; |
| 522 | |
| 523 | /* found a potential candidate, but we still need to |
| 524 | * check the serial number */ |
| 525 | if (keyring->serial <= bound) |
| 526 | continue; |
| 527 | |
| 528 | /* we've got a match */ |
| 529 | atomic_inc(&keyring->usage); |
| 530 | read_unlock(&keyring_name_lock); |
| 531 | goto error; |
| 532 | } |
| 533 | } |
| 534 | |
| 535 | read_unlock(&keyring_name_lock); |
| 536 | keyring = ERR_PTR(-ENOKEY); |
| 537 | |
| 538 | error: |
| 539 | return keyring; |
| 540 | |
| 541 | } /* end find_keyring_by_name() */ |
| 542 | |
| 543 | /*****************************************************************************/ |
| 544 | /* |
| 545 | * see if a cycle will will be created by inserting acyclic tree B in acyclic |
| 546 | * tree A at the topmost level (ie: as a direct child of A) |
| 547 | * - since we are adding B to A at the top level, checking for cycles should |
| 548 | * just be a matter of seeing if node A is somewhere in tree B |
| 549 | */ |
| 550 | static int keyring_detect_cycle(struct key *A, struct key *B) |
| 551 | { |
| 552 | struct { |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 553 | struct keyring_list *keylist; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 554 | int kix; |
| 555 | } stack[KEYRING_SEARCH_MAX_DEPTH]; |
| 556 | |
| 557 | struct keyring_list *keylist; |
| 558 | struct key *subtree, *key; |
| 559 | int sp, kix, ret; |
| 560 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 561 | rcu_read_lock(); |
| 562 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 563 | ret = -EDEADLK; |
| 564 | if (A == B) |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 565 | goto cycle_detected; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 566 | |
| 567 | subtree = B; |
| 568 | sp = 0; |
| 569 | |
| 570 | /* start processing a new keyring */ |
| 571 | descend: |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 572 | if (test_bit(KEY_FLAG_REVOKED, &subtree->flags)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 573 | goto not_this_keyring; |
| 574 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 575 | keylist = rcu_dereference(subtree->payload.subscriptions); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 576 | if (!keylist) |
| 577 | goto not_this_keyring; |
| 578 | kix = 0; |
| 579 | |
| 580 | ascend: |
| 581 | /* iterate through the remaining keys in this keyring */ |
| 582 | for (; kix < keylist->nkeys; kix++) { |
| 583 | key = keylist->keys[kix]; |
| 584 | |
| 585 | if (key == A) |
| 586 | goto cycle_detected; |
| 587 | |
| 588 | /* recursively check nested keyrings */ |
| 589 | if (key->type == &key_type_keyring) { |
| 590 | if (sp >= KEYRING_SEARCH_MAX_DEPTH) |
| 591 | goto too_deep; |
| 592 | |
| 593 | /* stack the current position */ |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 594 | stack[sp].keylist = keylist; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 595 | stack[sp].kix = kix; |
| 596 | sp++; |
| 597 | |
| 598 | /* begin again with the new keyring */ |
| 599 | subtree = key; |
| 600 | goto descend; |
| 601 | } |
| 602 | } |
| 603 | |
| 604 | /* the keyring we're looking at was disqualified or didn't contain a |
| 605 | * matching key */ |
| 606 | not_this_keyring: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 607 | if (sp > 0) { |
| 608 | /* resume the checking of a keyring higher up in the tree */ |
| 609 | sp--; |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 610 | keylist = stack[sp].keylist; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 611 | kix = stack[sp].kix + 1; |
| 612 | goto ascend; |
| 613 | } |
| 614 | |
| 615 | ret = 0; /* no cycles detected */ |
| 616 | |
| 617 | error: |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 618 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 619 | return ret; |
| 620 | |
| 621 | too_deep: |
| 622 | ret = -ELOOP; |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 623 | goto error; |
| 624 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 625 | cycle_detected: |
| 626 | ret = -EDEADLK; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 627 | goto error; |
| 628 | |
| 629 | } /* end keyring_detect_cycle() */ |
| 630 | |
| 631 | /*****************************************************************************/ |
| 632 | /* |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 633 | * dispose of a keyring list after the RCU grace period |
| 634 | */ |
| 635 | static void keyring_link_rcu_disposal(struct rcu_head *rcu) |
| 636 | { |
| 637 | struct keyring_list *klist = |
| 638 | container_of(rcu, struct keyring_list, rcu); |
| 639 | |
| 640 | kfree(klist); |
| 641 | |
| 642 | } /* end keyring_link_rcu_disposal() */ |
| 643 | |
| 644 | /*****************************************************************************/ |
| 645 | /* |
David Howells | cab8eb5 | 2006-01-08 01:02:45 -0800 | [diff] [blame] | 646 | * dispose of a keyring list after the RCU grace period, freeing the unlinked |
| 647 | * key |
| 648 | */ |
| 649 | static void keyring_unlink_rcu_disposal(struct rcu_head *rcu) |
| 650 | { |
| 651 | struct keyring_list *klist = |
| 652 | container_of(rcu, struct keyring_list, rcu); |
| 653 | |
| 654 | key_put(klist->keys[klist->delkey]); |
| 655 | kfree(klist); |
| 656 | |
| 657 | } /* end keyring_unlink_rcu_disposal() */ |
| 658 | |
| 659 | /*****************************************************************************/ |
| 660 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 661 | * link a key into to a keyring |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 662 | * - must be called with the keyring's semaphore write-locked |
David Howells | cab8eb5 | 2006-01-08 01:02:45 -0800 | [diff] [blame] | 663 | * - discard already extant link to matching key if there is one |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 664 | */ |
| 665 | int __key_link(struct key *keyring, struct key *key) |
| 666 | { |
| 667 | struct keyring_list *klist, *nklist; |
| 668 | unsigned max; |
| 669 | size_t size; |
David Howells | cab8eb5 | 2006-01-08 01:02:45 -0800 | [diff] [blame] | 670 | int loop, ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 671 | |
| 672 | ret = -EKEYREVOKED; |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 673 | if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 674 | goto error; |
| 675 | |
| 676 | ret = -ENOTDIR; |
| 677 | if (keyring->type != &key_type_keyring) |
| 678 | goto error; |
| 679 | |
| 680 | /* serialise link/link calls to prevent parallel calls causing a |
| 681 | * cycle when applied to two keyring in opposite orders */ |
| 682 | down_write(&keyring_serialise_link_sem); |
| 683 | |
| 684 | /* check that we aren't going to create a cycle adding one keyring to |
| 685 | * another */ |
| 686 | if (key->type == &key_type_keyring) { |
| 687 | ret = keyring_detect_cycle(keyring, key); |
| 688 | if (ret < 0) |
| 689 | goto error2; |
| 690 | } |
| 691 | |
David Howells | cab8eb5 | 2006-01-08 01:02:45 -0800 | [diff] [blame] | 692 | /* see if there's a matching key we can displace */ |
| 693 | klist = keyring->payload.subscriptions; |
| 694 | |
| 695 | if (klist && klist->nkeys > 0) { |
| 696 | struct key_type *type = key->type; |
| 697 | |
| 698 | for (loop = klist->nkeys - 1; loop >= 0; loop--) { |
| 699 | if (klist->keys[loop]->type == type && |
| 700 | strcmp(klist->keys[loop]->description, |
| 701 | key->description) == 0 |
| 702 | ) { |
| 703 | /* found a match - replace with new key */ |
| 704 | size = sizeof(struct key *) * klist->maxkeys; |
| 705 | size += sizeof(*klist); |
| 706 | BUG_ON(size > PAGE_SIZE); |
| 707 | |
| 708 | ret = -ENOMEM; |
Eric Sesterhenn | 48ad504 | 2006-12-06 20:33:47 -0800 | [diff] [blame] | 709 | nklist = kmemdup(klist, size, GFP_KERNEL); |
David Howells | cab8eb5 | 2006-01-08 01:02:45 -0800 | [diff] [blame] | 710 | if (!nklist) |
| 711 | goto error2; |
| 712 | |
David Howells | cab8eb5 | 2006-01-08 01:02:45 -0800 | [diff] [blame] | 713 | /* replace matched key */ |
| 714 | atomic_inc(&key->usage); |
| 715 | nklist->keys[loop] = key; |
| 716 | |
| 717 | rcu_assign_pointer( |
| 718 | keyring->payload.subscriptions, |
| 719 | nklist); |
| 720 | |
| 721 | /* dispose of the old keyring list and the |
| 722 | * displaced key */ |
| 723 | klist->delkey = loop; |
| 724 | call_rcu(&klist->rcu, |
| 725 | keyring_unlink_rcu_disposal); |
| 726 | |
| 727 | goto done; |
| 728 | } |
| 729 | } |
| 730 | } |
| 731 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 732 | /* check that we aren't going to overrun the user's quota */ |
| 733 | ret = key_payload_reserve(keyring, |
| 734 | keyring->datalen + KEYQUOTA_LINK_BYTES); |
| 735 | if (ret < 0) |
| 736 | goto error2; |
| 737 | |
| 738 | klist = keyring->payload.subscriptions; |
| 739 | |
| 740 | if (klist && klist->nkeys < klist->maxkeys) { |
| 741 | /* there's sufficient slack space to add directly */ |
| 742 | atomic_inc(&key->usage); |
| 743 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 744 | klist->keys[klist->nkeys] = key; |
| 745 | smp_wmb(); |
| 746 | klist->nkeys++; |
| 747 | smp_wmb(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 748 | } |
| 749 | else { |
| 750 | /* grow the key list */ |
| 751 | max = 4; |
| 752 | if (klist) |
| 753 | max += klist->maxkeys; |
| 754 | |
| 755 | ret = -ENFILE; |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 756 | if (max > 65535) |
| 757 | goto error3; |
David Howells | a4014d8 | 2005-07-07 17:57:03 -0700 | [diff] [blame] | 758 | size = sizeof(*klist) + sizeof(struct key *) * max; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 759 | if (size > PAGE_SIZE) |
| 760 | goto error3; |
| 761 | |
| 762 | ret = -ENOMEM; |
| 763 | nklist = kmalloc(size, GFP_KERNEL); |
| 764 | if (!nklist) |
| 765 | goto error3; |
| 766 | nklist->maxkeys = max; |
| 767 | nklist->nkeys = 0; |
| 768 | |
| 769 | if (klist) { |
| 770 | nklist->nkeys = klist->nkeys; |
| 771 | memcpy(nklist->keys, |
| 772 | klist->keys, |
| 773 | sizeof(struct key *) * klist->nkeys); |
| 774 | } |
| 775 | |
| 776 | /* add the key into the new space */ |
| 777 | atomic_inc(&key->usage); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 778 | nklist->keys[nklist->nkeys++] = key; |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 779 | |
| 780 | rcu_assign_pointer(keyring->payload.subscriptions, nklist); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 781 | |
| 782 | /* dispose of the old keyring list */ |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 783 | if (klist) |
| 784 | call_rcu(&klist->rcu, keyring_link_rcu_disposal); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 785 | } |
| 786 | |
David Howells | cab8eb5 | 2006-01-08 01:02:45 -0800 | [diff] [blame] | 787 | done: |
| 788 | ret = 0; |
| 789 | error2: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 790 | up_write(&keyring_serialise_link_sem); |
David Howells | cab8eb5 | 2006-01-08 01:02:45 -0800 | [diff] [blame] | 791 | error: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 792 | return ret; |
| 793 | |
David Howells | cab8eb5 | 2006-01-08 01:02:45 -0800 | [diff] [blame] | 794 | error3: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 795 | /* undo the quota changes */ |
| 796 | key_payload_reserve(keyring, |
| 797 | keyring->datalen - KEYQUOTA_LINK_BYTES); |
| 798 | goto error2; |
| 799 | |
| 800 | } /* end __key_link() */ |
| 801 | |
| 802 | /*****************************************************************************/ |
| 803 | /* |
| 804 | * link a key to a keyring |
| 805 | */ |
| 806 | int key_link(struct key *keyring, struct key *key) |
| 807 | { |
| 808 | int ret; |
| 809 | |
| 810 | key_check(keyring); |
| 811 | key_check(key); |
| 812 | |
| 813 | down_write(&keyring->sem); |
| 814 | ret = __key_link(keyring, key); |
| 815 | up_write(&keyring->sem); |
| 816 | |
| 817 | return ret; |
| 818 | |
| 819 | } /* end key_link() */ |
| 820 | |
| 821 | EXPORT_SYMBOL(key_link); |
| 822 | |
| 823 | /*****************************************************************************/ |
| 824 | /* |
| 825 | * unlink the first link to a key from a keyring |
| 826 | */ |
| 827 | int key_unlink(struct key *keyring, struct key *key) |
| 828 | { |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 829 | struct keyring_list *klist, *nklist; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 830 | int loop, ret; |
| 831 | |
| 832 | key_check(keyring); |
| 833 | key_check(key); |
| 834 | |
| 835 | ret = -ENOTDIR; |
| 836 | if (keyring->type != &key_type_keyring) |
| 837 | goto error; |
| 838 | |
| 839 | down_write(&keyring->sem); |
| 840 | |
| 841 | klist = keyring->payload.subscriptions; |
| 842 | if (klist) { |
| 843 | /* search the keyring for the key */ |
| 844 | for (loop = 0; loop < klist->nkeys; loop++) |
| 845 | if (klist->keys[loop] == key) |
| 846 | goto key_is_present; |
| 847 | } |
| 848 | |
| 849 | up_write(&keyring->sem); |
| 850 | ret = -ENOENT; |
| 851 | goto error; |
| 852 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 853 | key_is_present: |
| 854 | /* we need to copy the key list for RCU purposes */ |
David Howells | a4014d8 | 2005-07-07 17:57:03 -0700 | [diff] [blame] | 855 | nklist = kmalloc(sizeof(*klist) + |
| 856 | sizeof(struct key *) * klist->maxkeys, |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 857 | GFP_KERNEL); |
| 858 | if (!nklist) |
| 859 | goto nomem; |
| 860 | nklist->maxkeys = klist->maxkeys; |
| 861 | nklist->nkeys = klist->nkeys - 1; |
| 862 | |
| 863 | if (loop > 0) |
| 864 | memcpy(&nklist->keys[0], |
| 865 | &klist->keys[0], |
David Howells | a4014d8 | 2005-07-07 17:57:03 -0700 | [diff] [blame] | 866 | loop * sizeof(struct key *)); |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 867 | |
| 868 | if (loop < nklist->nkeys) |
| 869 | memcpy(&nklist->keys[loop], |
| 870 | &klist->keys[loop + 1], |
David Howells | a4014d8 | 2005-07-07 17:57:03 -0700 | [diff] [blame] | 871 | (nklist->nkeys - loop) * sizeof(struct key *)); |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 872 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 873 | /* adjust the user's quota */ |
| 874 | key_payload_reserve(keyring, |
| 875 | keyring->datalen - KEYQUOTA_LINK_BYTES); |
| 876 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 877 | rcu_assign_pointer(keyring->payload.subscriptions, nklist); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 878 | |
| 879 | up_write(&keyring->sem); |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 880 | |
| 881 | /* schedule for later cleanup */ |
| 882 | klist->delkey = loop; |
| 883 | call_rcu(&klist->rcu, keyring_unlink_rcu_disposal); |
| 884 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 885 | ret = 0; |
| 886 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 887 | error: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 888 | return ret; |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 889 | nomem: |
| 890 | ret = -ENOMEM; |
| 891 | up_write(&keyring->sem); |
| 892 | goto error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 893 | |
| 894 | } /* end key_unlink() */ |
| 895 | |
| 896 | EXPORT_SYMBOL(key_unlink); |
| 897 | |
| 898 | /*****************************************************************************/ |
| 899 | /* |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 900 | * dispose of a keyring list after the RCU grace period, releasing the keys it |
| 901 | * links to |
| 902 | */ |
| 903 | static void keyring_clear_rcu_disposal(struct rcu_head *rcu) |
| 904 | { |
| 905 | struct keyring_list *klist; |
| 906 | int loop; |
| 907 | |
| 908 | klist = container_of(rcu, struct keyring_list, rcu); |
| 909 | |
| 910 | for (loop = klist->nkeys - 1; loop >= 0; loop--) |
| 911 | key_put(klist->keys[loop]); |
| 912 | |
| 913 | kfree(klist); |
| 914 | |
| 915 | } /* end keyring_clear_rcu_disposal() */ |
| 916 | |
| 917 | /*****************************************************************************/ |
| 918 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 919 | * clear the specified process keyring |
| 920 | * - implements keyctl(KEYCTL_CLEAR) |
| 921 | */ |
| 922 | int keyring_clear(struct key *keyring) |
| 923 | { |
| 924 | struct keyring_list *klist; |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 925 | int ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 926 | |
| 927 | ret = -ENOTDIR; |
| 928 | if (keyring->type == &key_type_keyring) { |
| 929 | /* detach the pointer block with the locks held */ |
| 930 | down_write(&keyring->sem); |
| 931 | |
| 932 | klist = keyring->payload.subscriptions; |
| 933 | if (klist) { |
| 934 | /* adjust the quota */ |
| 935 | key_payload_reserve(keyring, |
| 936 | sizeof(struct keyring_list)); |
| 937 | |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 938 | rcu_assign_pointer(keyring->payload.subscriptions, |
| 939 | NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 940 | } |
| 941 | |
| 942 | up_write(&keyring->sem); |
| 943 | |
| 944 | /* free the keys after the locks have been dropped */ |
David Howells | 76d8aea | 2005-06-23 22:00:49 -0700 | [diff] [blame] | 945 | if (klist) |
| 946 | call_rcu(&klist->rcu, keyring_clear_rcu_disposal); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 947 | |
| 948 | ret = 0; |
| 949 | } |
| 950 | |
| 951 | return ret; |
| 952 | |
| 953 | } /* end keyring_clear() */ |
| 954 | |
| 955 | EXPORT_SYMBOL(keyring_clear); |
David Howells | 31204ed | 2006-06-26 00:24:51 -0700 | [diff] [blame] | 956 | |
| 957 | /*****************************************************************************/ |
| 958 | /* |
| 959 | * dispose of the links from a revoked keyring |
| 960 | * - called with the key sem write-locked |
| 961 | */ |
| 962 | static void keyring_revoke(struct key *keyring) |
| 963 | { |
| 964 | struct keyring_list *klist = keyring->payload.subscriptions; |
| 965 | |
| 966 | /* adjust the quota */ |
| 967 | key_payload_reserve(keyring, 0); |
| 968 | |
| 969 | if (klist) { |
| 970 | rcu_assign_pointer(keyring->payload.subscriptions, NULL); |
| 971 | call_rcu(&klist->rcu, keyring_clear_rcu_disposal); |
| 972 | } |
| 973 | |
| 974 | } /* end keyring_revoke() */ |