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973c9f4f | 1 | /* Manage a process's keyrings |
1da177e4 | 2 | * |
69664cf1 | 3 | * Copyright (C) 2004-2005, 2008 Red Hat, Inc. All Rights Reserved. |
1da177e4 LT |
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> | |
1da177e4 LT |
15 | #include <linux/keyctl.h> |
16 | #include <linux/fs.h> | |
17 | #include <linux/err.h> | |
bb003079 | 18 | #include <linux/mutex.h> |
ee18d64c | 19 | #include <linux/security.h> |
1d1e9756 | 20 | #include <linux/user_namespace.h> |
1da177e4 LT |
21 | #include <asm/uaccess.h> |
22 | #include "internal.h" | |
23 | ||
973c9f4f | 24 | /* Session keyring create vs join semaphore */ |
bb003079 | 25 | static DEFINE_MUTEX(key_session_mutex); |
1da177e4 | 26 | |
973c9f4f | 27 | /* User keyring creation semaphore */ |
69664cf1 DH |
28 | static DEFINE_MUTEX(key_user_keyring_mutex); |
29 | ||
973c9f4f | 30 | /* The root user's tracking struct */ |
1da177e4 LT |
31 | struct key_user root_key_user = { |
32 | .usage = ATOMIC_INIT(3), | |
76181c13 | 33 | .cons_lock = __MUTEX_INITIALIZER(root_key_user.cons_lock), |
6cfd76a2 | 34 | .lock = __SPIN_LOCK_UNLOCKED(root_key_user.lock), |
1da177e4 LT |
35 | .nkeys = ATOMIC_INIT(2), |
36 | .nikeys = ATOMIC_INIT(2), | |
37 | .uid = 0, | |
1d1e9756 | 38 | .user_ns = &init_user_ns, |
1da177e4 LT |
39 | }; |
40 | ||
1da177e4 | 41 | /* |
973c9f4f | 42 | * Install the user and user session keyrings for the current process's UID. |
1da177e4 | 43 | */ |
8bbf4976 | 44 | int install_user_keyrings(void) |
1da177e4 | 45 | { |
d84f4f99 DH |
46 | struct user_struct *user; |
47 | const struct cred *cred; | |
1da177e4 LT |
48 | struct key *uid_keyring, *session_keyring; |
49 | char buf[20]; | |
50 | int ret; | |
51 | ||
d84f4f99 DH |
52 | cred = current_cred(); |
53 | user = cred->user; | |
54 | ||
69664cf1 | 55 | kenter("%p{%u}", user, user->uid); |
1da177e4 | 56 | |
69664cf1 DH |
57 | if (user->uid_keyring) { |
58 | kleave(" = 0 [exist]"); | |
59 | return 0; | |
1da177e4 LT |
60 | } |
61 | ||
69664cf1 DH |
62 | mutex_lock(&key_user_keyring_mutex); |
63 | ret = 0; | |
1da177e4 | 64 | |
69664cf1 DH |
65 | if (!user->uid_keyring) { |
66 | /* get the UID-specific keyring | |
67 | * - there may be one in existence already as it may have been | |
68 | * pinned by a session, but the user_struct pointing to it | |
69 | * may have been destroyed by setuid */ | |
70 | sprintf(buf, "_uid.%u", user->uid); | |
71 | ||
72 | uid_keyring = find_keyring_by_name(buf, true); | |
73 | if (IS_ERR(uid_keyring)) { | |
74 | uid_keyring = keyring_alloc(buf, user->uid, (gid_t) -1, | |
d84f4f99 | 75 | cred, KEY_ALLOC_IN_QUOTA, |
69664cf1 DH |
76 | NULL); |
77 | if (IS_ERR(uid_keyring)) { | |
78 | ret = PTR_ERR(uid_keyring); | |
79 | goto error; | |
80 | } | |
81 | } | |
82 | ||
83 | /* get a default session keyring (which might also exist | |
84 | * already) */ | |
85 | sprintf(buf, "_uid_ses.%u", user->uid); | |
86 | ||
87 | session_keyring = find_keyring_by_name(buf, true); | |
88 | if (IS_ERR(session_keyring)) { | |
89 | session_keyring = | |
90 | keyring_alloc(buf, user->uid, (gid_t) -1, | |
d84f4f99 | 91 | cred, KEY_ALLOC_IN_QUOTA, NULL); |
69664cf1 DH |
92 | if (IS_ERR(session_keyring)) { |
93 | ret = PTR_ERR(session_keyring); | |
94 | goto error_release; | |
95 | } | |
96 | ||
97 | /* we install a link from the user session keyring to | |
98 | * the user keyring */ | |
99 | ret = key_link(session_keyring, uid_keyring); | |
100 | if (ret < 0) | |
101 | goto error_release_both; | |
102 | } | |
103 | ||
104 | /* install the keyrings */ | |
105 | user->uid_keyring = uid_keyring; | |
106 | user->session_keyring = session_keyring; | |
1da177e4 LT |
107 | } |
108 | ||
69664cf1 DH |
109 | mutex_unlock(&key_user_keyring_mutex); |
110 | kleave(" = 0"); | |
111 | return 0; | |
1da177e4 | 112 | |
69664cf1 DH |
113 | error_release_both: |
114 | key_put(session_keyring); | |
115 | error_release: | |
116 | key_put(uid_keyring); | |
664cceb0 | 117 | error: |
69664cf1 DH |
118 | mutex_unlock(&key_user_keyring_mutex); |
119 | kleave(" = %d", ret); | |
1da177e4 | 120 | return ret; |
69664cf1 | 121 | } |
1da177e4 | 122 | |
1da177e4 | 123 | /* |
973c9f4f DH |
124 | * Install a fresh thread keyring directly to new credentials. This keyring is |
125 | * allowed to overrun the quota. | |
1da177e4 | 126 | */ |
d84f4f99 | 127 | int install_thread_keyring_to_cred(struct cred *new) |
1da177e4 | 128 | { |
d84f4f99 | 129 | struct key *keyring; |
1da177e4 | 130 | |
d84f4f99 DH |
131 | keyring = keyring_alloc("_tid", new->uid, new->gid, new, |
132 | KEY_ALLOC_QUOTA_OVERRUN, NULL); | |
133 | if (IS_ERR(keyring)) | |
134 | return PTR_ERR(keyring); | |
1da177e4 | 135 | |
d84f4f99 DH |
136 | new->thread_keyring = keyring; |
137 | return 0; | |
138 | } | |
1da177e4 | 139 | |
1da177e4 | 140 | /* |
973c9f4f | 141 | * Install a fresh thread keyring, discarding the old one. |
1da177e4 | 142 | */ |
d84f4f99 | 143 | static int install_thread_keyring(void) |
1da177e4 | 144 | { |
d84f4f99 | 145 | struct cred *new; |
1da177e4 LT |
146 | int ret; |
147 | ||
d84f4f99 DH |
148 | new = prepare_creds(); |
149 | if (!new) | |
150 | return -ENOMEM; | |
1da177e4 | 151 | |
d84f4f99 DH |
152 | BUG_ON(new->thread_keyring); |
153 | ||
154 | ret = install_thread_keyring_to_cred(new); | |
155 | if (ret < 0) { | |
156 | abort_creds(new); | |
157 | return ret; | |
1da177e4 LT |
158 | } |
159 | ||
d84f4f99 DH |
160 | return commit_creds(new); |
161 | } | |
1da177e4 | 162 | |
d84f4f99 | 163 | /* |
973c9f4f DH |
164 | * Install a process keyring directly to a credentials struct. |
165 | * | |
166 | * Returns -EEXIST if there was already a process keyring, 0 if one installed, | |
167 | * and other value on any other error | |
d84f4f99 DH |
168 | */ |
169 | int install_process_keyring_to_cred(struct cred *new) | |
170 | { | |
171 | struct key *keyring; | |
172 | int ret; | |
1da177e4 | 173 | |
d84f4f99 DH |
174 | if (new->tgcred->process_keyring) |
175 | return -EEXIST; | |
176 | ||
177 | keyring = keyring_alloc("_pid", new->uid, new->gid, | |
178 | new, KEY_ALLOC_QUOTA_OVERRUN, NULL); | |
179 | if (IS_ERR(keyring)) | |
180 | return PTR_ERR(keyring); | |
181 | ||
182 | spin_lock_irq(&new->tgcred->lock); | |
183 | if (!new->tgcred->process_keyring) { | |
184 | new->tgcred->process_keyring = keyring; | |
185 | keyring = NULL; | |
186 | ret = 0; | |
187 | } else { | |
188 | ret = -EEXIST; | |
189 | } | |
190 | spin_unlock_irq(&new->tgcred->lock); | |
191 | key_put(keyring); | |
1da177e4 | 192 | return ret; |
d84f4f99 | 193 | } |
1da177e4 | 194 | |
1da177e4 | 195 | /* |
973c9f4f DH |
196 | * Make sure a process keyring is installed for the current process. The |
197 | * existing process keyring is not replaced. | |
198 | * | |
199 | * Returns 0 if there is a process keyring by the end of this function, some | |
200 | * error otherwise. | |
1da177e4 | 201 | */ |
d84f4f99 | 202 | static int install_process_keyring(void) |
1da177e4 | 203 | { |
d84f4f99 | 204 | struct cred *new; |
1da177e4 LT |
205 | int ret; |
206 | ||
d84f4f99 DH |
207 | new = prepare_creds(); |
208 | if (!new) | |
209 | return -ENOMEM; | |
1da177e4 | 210 | |
d84f4f99 DH |
211 | ret = install_process_keyring_to_cred(new); |
212 | if (ret < 0) { | |
213 | abort_creds(new); | |
27d63798 | 214 | return ret != -EEXIST ? ret : 0; |
1da177e4 LT |
215 | } |
216 | ||
d84f4f99 DH |
217 | return commit_creds(new); |
218 | } | |
1da177e4 | 219 | |
1da177e4 | 220 | /* |
973c9f4f | 221 | * Install a session keyring directly to a credentials struct. |
1da177e4 | 222 | */ |
685bfd2c | 223 | int install_session_keyring_to_cred(struct cred *cred, struct key *keyring) |
1da177e4 | 224 | { |
7e047ef5 | 225 | unsigned long flags; |
1da177e4 | 226 | struct key *old; |
1a26feb9 DH |
227 | |
228 | might_sleep(); | |
1da177e4 LT |
229 | |
230 | /* create an empty session keyring */ | |
231 | if (!keyring) { | |
7e047ef5 | 232 | flags = KEY_ALLOC_QUOTA_OVERRUN; |
d84f4f99 | 233 | if (cred->tgcred->session_keyring) |
7e047ef5 DH |
234 | flags = KEY_ALLOC_IN_QUOTA; |
235 | ||
d84f4f99 DH |
236 | keyring = keyring_alloc("_ses", cred->uid, cred->gid, |
237 | cred, flags, NULL); | |
1a26feb9 DH |
238 | if (IS_ERR(keyring)) |
239 | return PTR_ERR(keyring); | |
d84f4f99 | 240 | } else { |
1da177e4 LT |
241 | atomic_inc(&keyring->usage); |
242 | } | |
243 | ||
244 | /* install the keyring */ | |
d84f4f99 DH |
245 | spin_lock_irq(&cred->tgcred->lock); |
246 | old = cred->tgcred->session_keyring; | |
247 | rcu_assign_pointer(cred->tgcred->session_keyring, keyring); | |
248 | spin_unlock_irq(&cred->tgcred->lock); | |
1da177e4 | 249 | |
1a26feb9 DH |
250 | /* we're using RCU on the pointer, but there's no point synchronising |
251 | * on it if it didn't previously point to anything */ | |
252 | if (old) { | |
253 | synchronize_rcu(); | |
254 | key_put(old); | |
255 | } | |
1da177e4 | 256 | |
1a26feb9 | 257 | return 0; |
d84f4f99 | 258 | } |
1da177e4 | 259 | |
1da177e4 | 260 | /* |
973c9f4f DH |
261 | * Install a session keyring, discarding the old one. If a keyring is not |
262 | * supplied, an empty one is invented. | |
1da177e4 | 263 | */ |
d84f4f99 | 264 | static int install_session_keyring(struct key *keyring) |
1da177e4 | 265 | { |
d84f4f99 DH |
266 | struct cred *new; |
267 | int ret; | |
1da177e4 | 268 | |
d84f4f99 DH |
269 | new = prepare_creds(); |
270 | if (!new) | |
271 | return -ENOMEM; | |
1da177e4 | 272 | |
d84f4f99 DH |
273 | ret = install_session_keyring_to_cred(new, NULL); |
274 | if (ret < 0) { | |
275 | abort_creds(new); | |
276 | return ret; | |
277 | } | |
1da177e4 | 278 | |
d84f4f99 DH |
279 | return commit_creds(new); |
280 | } | |
1da177e4 | 281 | |
1da177e4 | 282 | /* |
973c9f4f | 283 | * Handle the fsuid changing. |
1da177e4 LT |
284 | */ |
285 | void key_fsuid_changed(struct task_struct *tsk) | |
286 | { | |
287 | /* update the ownership of the thread keyring */ | |
b6dff3ec DH |
288 | BUG_ON(!tsk->cred); |
289 | if (tsk->cred->thread_keyring) { | |
290 | down_write(&tsk->cred->thread_keyring->sem); | |
291 | tsk->cred->thread_keyring->uid = tsk->cred->fsuid; | |
292 | up_write(&tsk->cred->thread_keyring->sem); | |
1da177e4 | 293 | } |
a8b17ed0 | 294 | } |
1da177e4 | 295 | |
1da177e4 | 296 | /* |
973c9f4f | 297 | * Handle the fsgid changing. |
1da177e4 LT |
298 | */ |
299 | void key_fsgid_changed(struct task_struct *tsk) | |
300 | { | |
301 | /* update the ownership of the thread keyring */ | |
b6dff3ec DH |
302 | BUG_ON(!tsk->cred); |
303 | if (tsk->cred->thread_keyring) { | |
304 | down_write(&tsk->cred->thread_keyring->sem); | |
305 | tsk->cred->thread_keyring->gid = tsk->cred->fsgid; | |
306 | up_write(&tsk->cred->thread_keyring->sem); | |
1da177e4 | 307 | } |
a8b17ed0 | 308 | } |
1da177e4 | 309 | |
1da177e4 | 310 | /* |
973c9f4f DH |
311 | * Search the process keyrings attached to the supplied cred for the first |
312 | * matching key. | |
313 | * | |
314 | * The search criteria are the type and the match function. The description is | |
315 | * given to the match function as a parameter, but doesn't otherwise influence | |
316 | * the search. Typically the match function will compare the description | |
317 | * parameter to the key's description. | |
318 | * | |
319 | * This can only search keyrings that grant Search permission to the supplied | |
320 | * credentials. Keyrings linked to searched keyrings will also be searched if | |
321 | * they grant Search permission too. Keys can only be found if they grant | |
322 | * Search permission to the credentials. | |
323 | * | |
324 | * Returns a pointer to the key with the key usage count incremented if | |
325 | * successful, -EAGAIN if we didn't find any matching key or -ENOKEY if we only | |
326 | * matched negative keys. | |
327 | * | |
328 | * In the case of a successful return, the possession attribute is set on the | |
329 | * returned key reference. | |
1da177e4 | 330 | */ |
927942aa DH |
331 | key_ref_t search_my_process_keyrings(struct key_type *type, |
332 | const void *description, | |
333 | key_match_func_t match, | |
78b7280c | 334 | bool no_state_check, |
927942aa | 335 | const struct cred *cred) |
1da177e4 | 336 | { |
b5f545c8 | 337 | key_ref_t key_ref, ret, err; |
1da177e4 LT |
338 | |
339 | /* we want to return -EAGAIN or -ENOKEY if any of the keyrings were | |
340 | * searchable, but we failed to find a key or we found a negative key; | |
341 | * otherwise we want to return a sample error (probably -EACCES) if | |
342 | * none of the keyrings were searchable | |
343 | * | |
344 | * in terms of priority: success > -ENOKEY > -EAGAIN > other error | |
345 | */ | |
664cceb0 | 346 | key_ref = NULL; |
1da177e4 LT |
347 | ret = NULL; |
348 | err = ERR_PTR(-EAGAIN); | |
349 | ||
350 | /* search the thread keyring first */ | |
c69e8d9c | 351 | if (cred->thread_keyring) { |
664cceb0 | 352 | key_ref = keyring_search_aux( |
c69e8d9c | 353 | make_key_ref(cred->thread_keyring, 1), |
78b7280c | 354 | cred, type, description, match, no_state_check); |
664cceb0 | 355 | if (!IS_ERR(key_ref)) |
1da177e4 LT |
356 | goto found; |
357 | ||
664cceb0 | 358 | switch (PTR_ERR(key_ref)) { |
1da177e4 LT |
359 | case -EAGAIN: /* no key */ |
360 | if (ret) | |
361 | break; | |
362 | case -ENOKEY: /* negative key */ | |
664cceb0 | 363 | ret = key_ref; |
1da177e4 LT |
364 | break; |
365 | default: | |
664cceb0 | 366 | err = key_ref; |
1da177e4 LT |
367 | break; |
368 | } | |
369 | } | |
370 | ||
371 | /* search the process keyring second */ | |
bb952bb9 | 372 | if (cred->tgcred->process_keyring) { |
664cceb0 | 373 | key_ref = keyring_search_aux( |
bb952bb9 | 374 | make_key_ref(cred->tgcred->process_keyring, 1), |
78b7280c | 375 | cred, type, description, match, no_state_check); |
664cceb0 | 376 | if (!IS_ERR(key_ref)) |
1da177e4 LT |
377 | goto found; |
378 | ||
664cceb0 | 379 | switch (PTR_ERR(key_ref)) { |
1da177e4 LT |
380 | case -EAGAIN: /* no key */ |
381 | if (ret) | |
382 | break; | |
383 | case -ENOKEY: /* negative key */ | |
664cceb0 | 384 | ret = key_ref; |
1da177e4 LT |
385 | break; |
386 | default: | |
664cceb0 | 387 | err = key_ref; |
1da177e4 LT |
388 | break; |
389 | } | |
390 | } | |
391 | ||
3e30148c | 392 | /* search the session keyring */ |
bb952bb9 | 393 | if (cred->tgcred->session_keyring) { |
8589b4e0 | 394 | rcu_read_lock(); |
664cceb0 DH |
395 | key_ref = keyring_search_aux( |
396 | make_key_ref(rcu_dereference( | |
bb952bb9 | 397 | cred->tgcred->session_keyring), |
664cceb0 | 398 | 1), |
78b7280c | 399 | cred, type, description, match, no_state_check); |
8589b4e0 | 400 | rcu_read_unlock(); |
3e30148c | 401 | |
664cceb0 | 402 | if (!IS_ERR(key_ref)) |
3e30148c DH |
403 | goto found; |
404 | ||
664cceb0 | 405 | switch (PTR_ERR(key_ref)) { |
3e30148c DH |
406 | case -EAGAIN: /* no key */ |
407 | if (ret) | |
408 | break; | |
409 | case -ENOKEY: /* negative key */ | |
664cceb0 | 410 | ret = key_ref; |
3e30148c DH |
411 | break; |
412 | default: | |
664cceb0 | 413 | err = key_ref; |
3e30148c DH |
414 | break; |
415 | } | |
b5f545c8 DH |
416 | } |
417 | /* or search the user-session keyring */ | |
c69e8d9c | 418 | else if (cred->user->session_keyring) { |
b5f545c8 | 419 | key_ref = keyring_search_aux( |
c69e8d9c | 420 | make_key_ref(cred->user->session_keyring, 1), |
78b7280c | 421 | cred, type, description, match, no_state_check); |
664cceb0 | 422 | if (!IS_ERR(key_ref)) |
3e30148c DH |
423 | goto found; |
424 | ||
664cceb0 | 425 | switch (PTR_ERR(key_ref)) { |
3e30148c DH |
426 | case -EAGAIN: /* no key */ |
427 | if (ret) | |
428 | break; | |
429 | case -ENOKEY: /* negative key */ | |
664cceb0 | 430 | ret = key_ref; |
3e30148c DH |
431 | break; |
432 | default: | |
664cceb0 | 433 | err = key_ref; |
3e30148c DH |
434 | break; |
435 | } | |
8589b4e0 | 436 | } |
b5f545c8 | 437 | |
927942aa DH |
438 | /* no key - decide on the error we're going to go for */ |
439 | key_ref = ret ? ret : err; | |
440 | ||
441 | found: | |
442 | return key_ref; | |
443 | } | |
444 | ||
927942aa | 445 | /* |
973c9f4f DH |
446 | * Search the process keyrings attached to the supplied cred for the first |
447 | * matching key in the manner of search_my_process_keyrings(), but also search | |
448 | * the keys attached to the assumed authorisation key using its credentials if | |
449 | * one is available. | |
450 | * | |
451 | * Return same as search_my_process_keyrings(). | |
927942aa DH |
452 | */ |
453 | key_ref_t search_process_keyrings(struct key_type *type, | |
454 | const void *description, | |
455 | key_match_func_t match, | |
456 | const struct cred *cred) | |
457 | { | |
458 | struct request_key_auth *rka; | |
459 | key_ref_t key_ref, ret = ERR_PTR(-EACCES), err; | |
460 | ||
461 | might_sleep(); | |
462 | ||
78b7280c DH |
463 | key_ref = search_my_process_keyrings(type, description, match, |
464 | false, cred); | |
927942aa DH |
465 | if (!IS_ERR(key_ref)) |
466 | goto found; | |
467 | err = key_ref; | |
468 | ||
b5f545c8 DH |
469 | /* if this process has an instantiation authorisation key, then we also |
470 | * search the keyrings of the process mentioned there | |
471 | * - we don't permit access to request_key auth keys via this method | |
472 | */ | |
c69e8d9c | 473 | if (cred->request_key_auth && |
d84f4f99 | 474 | cred == current_cred() && |
04c567d9 | 475 | type != &key_type_request_key_auth |
b5f545c8 | 476 | ) { |
04c567d9 | 477 | /* defend against the auth key being revoked */ |
c69e8d9c | 478 | down_read(&cred->request_key_auth->sem); |
b5f545c8 | 479 | |
c69e8d9c DH |
480 | if (key_validate(cred->request_key_auth) == 0) { |
481 | rka = cred->request_key_auth->payload.data; | |
b5f545c8 | 482 | |
04c567d9 | 483 | key_ref = search_process_keyrings(type, description, |
d84f4f99 | 484 | match, rka->cred); |
1da177e4 | 485 | |
c69e8d9c | 486 | up_read(&cred->request_key_auth->sem); |
04c567d9 DH |
487 | |
488 | if (!IS_ERR(key_ref)) | |
489 | goto found; | |
490 | ||
927942aa | 491 | ret = key_ref; |
04c567d9 | 492 | } else { |
c69e8d9c | 493 | up_read(&cred->request_key_auth->sem); |
3e30148c | 494 | } |
1da177e4 LT |
495 | } |
496 | ||
497 | /* no key - decide on the error we're going to go for */ | |
927942aa DH |
498 | if (err == ERR_PTR(-ENOKEY) || ret == ERR_PTR(-ENOKEY)) |
499 | key_ref = ERR_PTR(-ENOKEY); | |
500 | else if (err == ERR_PTR(-EACCES)) | |
501 | key_ref = ret; | |
502 | else | |
503 | key_ref = err; | |
1da177e4 | 504 | |
3e30148c | 505 | found: |
664cceb0 | 506 | return key_ref; |
a8b17ed0 | 507 | } |
1da177e4 | 508 | |
664cceb0 | 509 | /* |
973c9f4f | 510 | * See if the key we're looking at is the target key. |
664cceb0 | 511 | */ |
927942aa | 512 | int lookup_user_key_possessed(const struct key *key, const void *target) |
664cceb0 DH |
513 | { |
514 | return key == target; | |
a8b17ed0 | 515 | } |
664cceb0 | 516 | |
1da177e4 | 517 | /* |
973c9f4f DH |
518 | * Look up a key ID given us by userspace with a given permissions mask to get |
519 | * the key it refers to. | |
520 | * | |
521 | * Flags can be passed to request that special keyrings be created if referred | |
522 | * to directly, to permit partially constructed keys to be found and to skip | |
523 | * validity and permission checks on the found key. | |
524 | * | |
525 | * Returns a pointer to the key with an incremented usage count if successful; | |
526 | * -EINVAL if the key ID is invalid; -ENOKEY if the key ID does not correspond | |
527 | * to a key or the best found key was a negative key; -EKEYREVOKED or | |
528 | * -EKEYEXPIRED if the best found key was revoked or expired; -EACCES if the | |
529 | * found key doesn't grant the requested permit or the LSM denied access to it; | |
530 | * or -ENOMEM if a special keyring couldn't be created. | |
531 | * | |
532 | * In the case of a successful return, the possession attribute is set on the | |
533 | * returned key reference. | |
1da177e4 | 534 | */ |
5593122e | 535 | key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags, |
8bbf4976 | 536 | key_perm_t perm) |
1da177e4 | 537 | { |
8bbf4976 | 538 | struct request_key_auth *rka; |
d84f4f99 | 539 | const struct cred *cred; |
1da177e4 | 540 | struct key *key; |
b6dff3ec | 541 | key_ref_t key_ref, skey_ref; |
1da177e4 LT |
542 | int ret; |
543 | ||
bb952bb9 DH |
544 | try_again: |
545 | cred = get_current_cred(); | |
664cceb0 | 546 | key_ref = ERR_PTR(-ENOKEY); |
1da177e4 LT |
547 | |
548 | switch (id) { | |
549 | case KEY_SPEC_THREAD_KEYRING: | |
b6dff3ec | 550 | if (!cred->thread_keyring) { |
5593122e | 551 | if (!(lflags & KEY_LOOKUP_CREATE)) |
1da177e4 LT |
552 | goto error; |
553 | ||
8bbf4976 | 554 | ret = install_thread_keyring(); |
1da177e4 | 555 | if (ret < 0) { |
4d09ec0f | 556 | key_ref = ERR_PTR(ret); |
1da177e4 LT |
557 | goto error; |
558 | } | |
bb952bb9 | 559 | goto reget_creds; |
1da177e4 LT |
560 | } |
561 | ||
b6dff3ec | 562 | key = cred->thread_keyring; |
1da177e4 | 563 | atomic_inc(&key->usage); |
664cceb0 | 564 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
565 | break; |
566 | ||
567 | case KEY_SPEC_PROCESS_KEYRING: | |
bb952bb9 | 568 | if (!cred->tgcred->process_keyring) { |
5593122e | 569 | if (!(lflags & KEY_LOOKUP_CREATE)) |
1da177e4 LT |
570 | goto error; |
571 | ||
8bbf4976 | 572 | ret = install_process_keyring(); |
1da177e4 | 573 | if (ret < 0) { |
4d09ec0f | 574 | key_ref = ERR_PTR(ret); |
1da177e4 LT |
575 | goto error; |
576 | } | |
bb952bb9 | 577 | goto reget_creds; |
1da177e4 LT |
578 | } |
579 | ||
bb952bb9 | 580 | key = cred->tgcred->process_keyring; |
1da177e4 | 581 | atomic_inc(&key->usage); |
664cceb0 | 582 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
583 | break; |
584 | ||
585 | case KEY_SPEC_SESSION_KEYRING: | |
bb952bb9 | 586 | if (!cred->tgcred->session_keyring) { |
1da177e4 LT |
587 | /* always install a session keyring upon access if one |
588 | * doesn't exist yet */ | |
8bbf4976 | 589 | ret = install_user_keyrings(); |
69664cf1 DH |
590 | if (ret < 0) |
591 | goto error; | |
b6dff3ec DH |
592 | ret = install_session_keyring( |
593 | cred->user->session_keyring); | |
d84f4f99 | 594 | |
1da177e4 LT |
595 | if (ret < 0) |
596 | goto error; | |
bb952bb9 | 597 | goto reget_creds; |
1da177e4 LT |
598 | } |
599 | ||
3e30148c | 600 | rcu_read_lock(); |
bb952bb9 | 601 | key = rcu_dereference(cred->tgcred->session_keyring); |
1da177e4 | 602 | atomic_inc(&key->usage); |
3e30148c | 603 | rcu_read_unlock(); |
664cceb0 | 604 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
605 | break; |
606 | ||
607 | case KEY_SPEC_USER_KEYRING: | |
b6dff3ec | 608 | if (!cred->user->uid_keyring) { |
8bbf4976 | 609 | ret = install_user_keyrings(); |
69664cf1 DH |
610 | if (ret < 0) |
611 | goto error; | |
612 | } | |
613 | ||
b6dff3ec | 614 | key = cred->user->uid_keyring; |
1da177e4 | 615 | atomic_inc(&key->usage); |
664cceb0 | 616 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
617 | break; |
618 | ||
619 | case KEY_SPEC_USER_SESSION_KEYRING: | |
b6dff3ec | 620 | if (!cred->user->session_keyring) { |
8bbf4976 | 621 | ret = install_user_keyrings(); |
69664cf1 DH |
622 | if (ret < 0) |
623 | goto error; | |
624 | } | |
625 | ||
b6dff3ec | 626 | key = cred->user->session_keyring; |
1da177e4 | 627 | atomic_inc(&key->usage); |
664cceb0 | 628 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
629 | break; |
630 | ||
631 | case KEY_SPEC_GROUP_KEYRING: | |
632 | /* group keyrings are not yet supported */ | |
4d09ec0f | 633 | key_ref = ERR_PTR(-EINVAL); |
1da177e4 LT |
634 | goto error; |
635 | ||
b5f545c8 | 636 | case KEY_SPEC_REQKEY_AUTH_KEY: |
b6dff3ec | 637 | key = cred->request_key_auth; |
b5f545c8 DH |
638 | if (!key) |
639 | goto error; | |
640 | ||
641 | atomic_inc(&key->usage); | |
642 | key_ref = make_key_ref(key, 1); | |
643 | break; | |
644 | ||
8bbf4976 | 645 | case KEY_SPEC_REQUESTOR_KEYRING: |
b6dff3ec | 646 | if (!cred->request_key_auth) |
8bbf4976 DH |
647 | goto error; |
648 | ||
b6dff3ec DH |
649 | down_read(&cred->request_key_auth->sem); |
650 | if (cred->request_key_auth->flags & KEY_FLAG_REVOKED) { | |
8bbf4976 DH |
651 | key_ref = ERR_PTR(-EKEYREVOKED); |
652 | key = NULL; | |
653 | } else { | |
b6dff3ec | 654 | rka = cred->request_key_auth->payload.data; |
8bbf4976 DH |
655 | key = rka->dest_keyring; |
656 | atomic_inc(&key->usage); | |
657 | } | |
b6dff3ec | 658 | up_read(&cred->request_key_auth->sem); |
8bbf4976 DH |
659 | if (!key) |
660 | goto error; | |
661 | key_ref = make_key_ref(key, 1); | |
662 | break; | |
663 | ||
1da177e4 | 664 | default: |
664cceb0 | 665 | key_ref = ERR_PTR(-EINVAL); |
1da177e4 LT |
666 | if (id < 1) |
667 | goto error; | |
668 | ||
669 | key = key_lookup(id); | |
664cceb0 | 670 | if (IS_ERR(key)) { |
e231c2ee | 671 | key_ref = ERR_CAST(key); |
1da177e4 | 672 | goto error; |
664cceb0 DH |
673 | } |
674 | ||
675 | key_ref = make_key_ref(key, 0); | |
676 | ||
677 | /* check to see if we possess the key */ | |
678 | skey_ref = search_process_keyrings(key->type, key, | |
679 | lookup_user_key_possessed, | |
d84f4f99 | 680 | cred); |
664cceb0 DH |
681 | |
682 | if (!IS_ERR(skey_ref)) { | |
683 | key_put(key); | |
684 | key_ref = skey_ref; | |
685 | } | |
686 | ||
1da177e4 LT |
687 | break; |
688 | } | |
689 | ||
5593122e DH |
690 | /* unlink does not use the nominated key in any way, so can skip all |
691 | * the permission checks as it is only concerned with the keyring */ | |
692 | if (lflags & KEY_LOOKUP_FOR_UNLINK) { | |
693 | ret = 0; | |
694 | goto error; | |
695 | } | |
696 | ||
697 | if (!(lflags & KEY_LOOKUP_PARTIAL)) { | |
76181c13 DH |
698 | ret = wait_for_key_construction(key, true); |
699 | switch (ret) { | |
700 | case -ERESTARTSYS: | |
701 | goto invalid_key; | |
702 | default: | |
703 | if (perm) | |
704 | goto invalid_key; | |
705 | case 0: | |
706 | break; | |
707 | } | |
708 | } else if (perm) { | |
1da177e4 LT |
709 | ret = key_validate(key); |
710 | if (ret < 0) | |
711 | goto invalid_key; | |
712 | } | |
713 | ||
714 | ret = -EIO; | |
5593122e DH |
715 | if (!(lflags & KEY_LOOKUP_PARTIAL) && |
716 | !test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) | |
1da177e4 LT |
717 | goto invalid_key; |
718 | ||
3e30148c | 719 | /* check the permissions */ |
d84f4f99 | 720 | ret = key_task_permission(key_ref, cred, perm); |
29db9190 | 721 | if (ret < 0) |
1da177e4 LT |
722 | goto invalid_key; |
723 | ||
664cceb0 | 724 | error: |
bb952bb9 | 725 | put_cred(cred); |
664cceb0 | 726 | return key_ref; |
1da177e4 | 727 | |
664cceb0 DH |
728 | invalid_key: |
729 | key_ref_put(key_ref); | |
730 | key_ref = ERR_PTR(ret); | |
1da177e4 LT |
731 | goto error; |
732 | ||
bb952bb9 DH |
733 | /* if we attempted to install a keyring, then it may have caused new |
734 | * creds to be installed */ | |
735 | reget_creds: | |
736 | put_cred(cred); | |
737 | goto try_again; | |
a8b17ed0 | 738 | } |
bb952bb9 | 739 | |
1da177e4 | 740 | /* |
973c9f4f DH |
741 | * Join the named keyring as the session keyring if possible else attempt to |
742 | * create a new one of that name and join that. | |
743 | * | |
744 | * If the name is NULL, an empty anonymous keyring will be installed as the | |
745 | * session keyring. | |
746 | * | |
747 | * Named session keyrings are joined with a semaphore held to prevent the | |
748 | * keyrings from going away whilst the attempt is made to going them and also | |
749 | * to prevent a race in creating compatible session keyrings. | |
1da177e4 LT |
750 | */ |
751 | long join_session_keyring(const char *name) | |
752 | { | |
d84f4f99 DH |
753 | const struct cred *old; |
754 | struct cred *new; | |
1da177e4 | 755 | struct key *keyring; |
d84f4f99 DH |
756 | long ret, serial; |
757 | ||
758 | /* only permit this if there's a single thread in the thread group - | |
759 | * this avoids us having to adjust the creds on all threads and risking | |
760 | * ENOMEM */ | |
5bb459bb | 761 | if (!current_is_single_threaded()) |
d84f4f99 DH |
762 | return -EMLINK; |
763 | ||
764 | new = prepare_creds(); | |
765 | if (!new) | |
766 | return -ENOMEM; | |
767 | old = current_cred(); | |
1da177e4 LT |
768 | |
769 | /* if no name is provided, install an anonymous keyring */ | |
770 | if (!name) { | |
d84f4f99 | 771 | ret = install_session_keyring_to_cred(new, NULL); |
1da177e4 LT |
772 | if (ret < 0) |
773 | goto error; | |
774 | ||
d84f4f99 DH |
775 | serial = new->tgcred->session_keyring->serial; |
776 | ret = commit_creds(new); | |
777 | if (ret == 0) | |
778 | ret = serial; | |
779 | goto okay; | |
1da177e4 LT |
780 | } |
781 | ||
782 | /* allow the user to join or create a named keyring */ | |
bb003079 | 783 | mutex_lock(&key_session_mutex); |
1da177e4 LT |
784 | |
785 | /* look for an existing keyring of this name */ | |
69664cf1 | 786 | keyring = find_keyring_by_name(name, false); |
1da177e4 LT |
787 | if (PTR_ERR(keyring) == -ENOKEY) { |
788 | /* not found - try and create a new one */ | |
d84f4f99 | 789 | keyring = keyring_alloc(name, old->uid, old->gid, old, |
7e047ef5 | 790 | KEY_ALLOC_IN_QUOTA, NULL); |
1da177e4 LT |
791 | if (IS_ERR(keyring)) { |
792 | ret = PTR_ERR(keyring); | |
bcf945d3 | 793 | goto error2; |
1da177e4 | 794 | } |
d84f4f99 | 795 | } else if (IS_ERR(keyring)) { |
1da177e4 LT |
796 | ret = PTR_ERR(keyring); |
797 | goto error2; | |
798 | } | |
799 | ||
800 | /* we've got a keyring - now to install it */ | |
d84f4f99 | 801 | ret = install_session_keyring_to_cred(new, keyring); |
1da177e4 LT |
802 | if (ret < 0) |
803 | goto error2; | |
804 | ||
d84f4f99 DH |
805 | commit_creds(new); |
806 | mutex_unlock(&key_session_mutex); | |
807 | ||
1da177e4 LT |
808 | ret = keyring->serial; |
809 | key_put(keyring); | |
d84f4f99 DH |
810 | okay: |
811 | return ret; | |
1da177e4 | 812 | |
664cceb0 | 813 | error2: |
bb003079 | 814 | mutex_unlock(&key_session_mutex); |
664cceb0 | 815 | error: |
d84f4f99 | 816 | abort_creds(new); |
1da177e4 | 817 | return ret; |
d84f4f99 | 818 | } |
ee18d64c DH |
819 | |
820 | /* | |
973c9f4f DH |
821 | * Replace a process's session keyring on behalf of one of its children when |
822 | * the target process is about to resume userspace execution. | |
ee18d64c DH |
823 | */ |
824 | void key_replace_session_keyring(void) | |
825 | { | |
826 | const struct cred *old; | |
827 | struct cred *new; | |
828 | ||
829 | if (!current->replacement_session_keyring) | |
830 | return; | |
831 | ||
832 | write_lock_irq(&tasklist_lock); | |
833 | new = current->replacement_session_keyring; | |
834 | current->replacement_session_keyring = NULL; | |
835 | write_unlock_irq(&tasklist_lock); | |
836 | ||
837 | if (!new) | |
838 | return; | |
839 | ||
840 | old = current_cred(); | |
841 | new-> uid = old-> uid; | |
842 | new-> euid = old-> euid; | |
843 | new-> suid = old-> suid; | |
844 | new->fsuid = old->fsuid; | |
845 | new-> gid = old-> gid; | |
846 | new-> egid = old-> egid; | |
847 | new-> sgid = old-> sgid; | |
848 | new->fsgid = old->fsgid; | |
849 | new->user = get_uid(old->user); | |
f7285b5d | 850 | new->user_ns = new->user->user_ns; |
ee18d64c DH |
851 | new->group_info = get_group_info(old->group_info); |
852 | ||
853 | new->securebits = old->securebits; | |
854 | new->cap_inheritable = old->cap_inheritable; | |
855 | new->cap_permitted = old->cap_permitted; | |
856 | new->cap_effective = old->cap_effective; | |
857 | new->cap_bset = old->cap_bset; | |
858 | ||
859 | new->jit_keyring = old->jit_keyring; | |
860 | new->thread_keyring = key_get(old->thread_keyring); | |
861 | new->tgcred->tgid = old->tgcred->tgid; | |
862 | new->tgcred->process_keyring = key_get(old->tgcred->process_keyring); | |
863 | ||
864 | security_transfer_creds(new, old); | |
865 | ||
866 | commit_creds(new); | |
867 | } |