Commit | Line | Data |
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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 | 48 | struct key *uid_keyring, *session_keyring; |
96b5c8fe | 49 | key_perm_t user_keyring_perm; |
1da177e4 LT |
50 | char buf[20]; |
51 | int ret; | |
52 | ||
96b5c8fe | 53 | user_keyring_perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL; |
d84f4f99 DH |
54 | cred = current_cred(); |
55 | user = cred->user; | |
56 | ||
69664cf1 | 57 | kenter("%p{%u}", user, user->uid); |
1da177e4 | 58 | |
69664cf1 DH |
59 | if (user->uid_keyring) { |
60 | kleave(" = 0 [exist]"); | |
61 | return 0; | |
1da177e4 LT |
62 | } |
63 | ||
69664cf1 DH |
64 | mutex_lock(&key_user_keyring_mutex); |
65 | ret = 0; | |
1da177e4 | 66 | |
69664cf1 DH |
67 | if (!user->uid_keyring) { |
68 | /* get the UID-specific keyring | |
69 | * - there may be one in existence already as it may have been | |
70 | * pinned by a session, but the user_struct pointing to it | |
71 | * may have been destroyed by setuid */ | |
72 | sprintf(buf, "_uid.%u", user->uid); | |
73 | ||
74 | uid_keyring = find_keyring_by_name(buf, true); | |
75 | if (IS_ERR(uid_keyring)) { | |
76 | uid_keyring = keyring_alloc(buf, user->uid, (gid_t) -1, | |
96b5c8fe DH |
77 | cred, user_keyring_perm, |
78 | KEY_ALLOC_IN_QUOTA, NULL); | |
69664cf1 DH |
79 | if (IS_ERR(uid_keyring)) { |
80 | ret = PTR_ERR(uid_keyring); | |
81 | goto error; | |
82 | } | |
83 | } | |
84 | ||
85 | /* get a default session keyring (which might also exist | |
86 | * already) */ | |
87 | sprintf(buf, "_uid_ses.%u", user->uid); | |
88 | ||
89 | session_keyring = find_keyring_by_name(buf, true); | |
90 | if (IS_ERR(session_keyring)) { | |
91 | session_keyring = | |
92 | keyring_alloc(buf, user->uid, (gid_t) -1, | |
96b5c8fe DH |
93 | cred, user_keyring_perm, |
94 | KEY_ALLOC_IN_QUOTA, NULL); | |
69664cf1 DH |
95 | if (IS_ERR(session_keyring)) { |
96 | ret = PTR_ERR(session_keyring); | |
97 | goto error_release; | |
98 | } | |
99 | ||
100 | /* we install a link from the user session keyring to | |
101 | * the user keyring */ | |
102 | ret = key_link(session_keyring, uid_keyring); | |
103 | if (ret < 0) | |
104 | goto error_release_both; | |
105 | } | |
106 | ||
107 | /* install the keyrings */ | |
108 | user->uid_keyring = uid_keyring; | |
109 | user->session_keyring = session_keyring; | |
1da177e4 LT |
110 | } |
111 | ||
69664cf1 DH |
112 | mutex_unlock(&key_user_keyring_mutex); |
113 | kleave(" = 0"); | |
114 | return 0; | |
1da177e4 | 115 | |
69664cf1 DH |
116 | error_release_both: |
117 | key_put(session_keyring); | |
118 | error_release: | |
119 | key_put(uid_keyring); | |
664cceb0 | 120 | error: |
69664cf1 DH |
121 | mutex_unlock(&key_user_keyring_mutex); |
122 | kleave(" = %d", ret); | |
1da177e4 | 123 | return ret; |
69664cf1 | 124 | } |
1da177e4 | 125 | |
1da177e4 | 126 | /* |
973c9f4f DH |
127 | * Install a fresh thread keyring directly to new credentials. This keyring is |
128 | * allowed to overrun the quota. | |
1da177e4 | 129 | */ |
d84f4f99 | 130 | int install_thread_keyring_to_cred(struct cred *new) |
1da177e4 | 131 | { |
d84f4f99 | 132 | struct key *keyring; |
1da177e4 | 133 | |
d84f4f99 | 134 | keyring = keyring_alloc("_tid", new->uid, new->gid, new, |
96b5c8fe | 135 | KEY_POS_ALL | KEY_USR_VIEW, |
d84f4f99 DH |
136 | KEY_ALLOC_QUOTA_OVERRUN, NULL); |
137 | if (IS_ERR(keyring)) | |
138 | return PTR_ERR(keyring); | |
1da177e4 | 139 | |
d84f4f99 DH |
140 | new->thread_keyring = keyring; |
141 | return 0; | |
142 | } | |
1da177e4 | 143 | |
1da177e4 | 144 | /* |
973c9f4f | 145 | * Install a fresh thread keyring, discarding the old one. |
1da177e4 | 146 | */ |
d84f4f99 | 147 | static int install_thread_keyring(void) |
1da177e4 | 148 | { |
d84f4f99 | 149 | struct cred *new; |
1da177e4 LT |
150 | int ret; |
151 | ||
d84f4f99 DH |
152 | new = prepare_creds(); |
153 | if (!new) | |
154 | return -ENOMEM; | |
1da177e4 | 155 | |
d84f4f99 DH |
156 | BUG_ON(new->thread_keyring); |
157 | ||
158 | ret = install_thread_keyring_to_cred(new); | |
159 | if (ret < 0) { | |
160 | abort_creds(new); | |
161 | return ret; | |
1da177e4 LT |
162 | } |
163 | ||
d84f4f99 DH |
164 | return commit_creds(new); |
165 | } | |
1da177e4 | 166 | |
d84f4f99 | 167 | /* |
973c9f4f DH |
168 | * Install a process keyring directly to a credentials struct. |
169 | * | |
170 | * Returns -EEXIST if there was already a process keyring, 0 if one installed, | |
171 | * and other value on any other error | |
d84f4f99 DH |
172 | */ |
173 | int install_process_keyring_to_cred(struct cred *new) | |
174 | { | |
175 | struct key *keyring; | |
1da177e4 | 176 | |
3a50597d | 177 | if (new->process_keyring) |
d84f4f99 DH |
178 | return -EEXIST; |
179 | ||
96b5c8fe DH |
180 | keyring = keyring_alloc("_pid", new->uid, new->gid, new, |
181 | KEY_POS_ALL | KEY_USR_VIEW, | |
182 | KEY_ALLOC_QUOTA_OVERRUN, NULL); | |
d84f4f99 DH |
183 | if (IS_ERR(keyring)) |
184 | return PTR_ERR(keyring); | |
185 | ||
3a50597d DH |
186 | new->process_keyring = keyring; |
187 | return 0; | |
d84f4f99 | 188 | } |
1da177e4 | 189 | |
1da177e4 | 190 | /* |
973c9f4f DH |
191 | * Make sure a process keyring is installed for the current process. The |
192 | * existing process keyring is not replaced. | |
193 | * | |
194 | * Returns 0 if there is a process keyring by the end of this function, some | |
195 | * error otherwise. | |
1da177e4 | 196 | */ |
d84f4f99 | 197 | static int install_process_keyring(void) |
1da177e4 | 198 | { |
d84f4f99 | 199 | struct cred *new; |
1da177e4 LT |
200 | int ret; |
201 | ||
d84f4f99 DH |
202 | new = prepare_creds(); |
203 | if (!new) | |
204 | return -ENOMEM; | |
1da177e4 | 205 | |
d84f4f99 DH |
206 | ret = install_process_keyring_to_cred(new); |
207 | if (ret < 0) { | |
208 | abort_creds(new); | |
27d63798 | 209 | return ret != -EEXIST ? ret : 0; |
1da177e4 LT |
210 | } |
211 | ||
d84f4f99 DH |
212 | return commit_creds(new); |
213 | } | |
1da177e4 | 214 | |
1da177e4 | 215 | /* |
973c9f4f | 216 | * Install a session keyring directly to a credentials struct. |
1da177e4 | 217 | */ |
685bfd2c | 218 | int install_session_keyring_to_cred(struct cred *cred, struct key *keyring) |
1da177e4 | 219 | { |
7e047ef5 | 220 | unsigned long flags; |
1da177e4 | 221 | struct key *old; |
1a26feb9 DH |
222 | |
223 | might_sleep(); | |
1da177e4 LT |
224 | |
225 | /* create an empty session keyring */ | |
226 | if (!keyring) { | |
7e047ef5 | 227 | flags = KEY_ALLOC_QUOTA_OVERRUN; |
3a50597d | 228 | if (cred->session_keyring) |
7e047ef5 DH |
229 | flags = KEY_ALLOC_IN_QUOTA; |
230 | ||
96b5c8fe DH |
231 | keyring = keyring_alloc("_ses", cred->uid, cred->gid, cred, |
232 | KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ, | |
233 | flags, NULL); | |
1a26feb9 DH |
234 | if (IS_ERR(keyring)) |
235 | return PTR_ERR(keyring); | |
d84f4f99 | 236 | } else { |
1da177e4 LT |
237 | atomic_inc(&keyring->usage); |
238 | } | |
239 | ||
240 | /* install the keyring */ | |
3a50597d DH |
241 | old = cred->session_keyring; |
242 | rcu_assign_pointer(cred->session_keyring, keyring); | |
243 | ||
244 | if (old) | |
1a26feb9 | 245 | key_put(old); |
1da177e4 | 246 | |
1a26feb9 | 247 | return 0; |
d84f4f99 | 248 | } |
1da177e4 | 249 | |
1da177e4 | 250 | /* |
973c9f4f DH |
251 | * Install a session keyring, discarding the old one. If a keyring is not |
252 | * supplied, an empty one is invented. | |
1da177e4 | 253 | */ |
d84f4f99 | 254 | static int install_session_keyring(struct key *keyring) |
1da177e4 | 255 | { |
d84f4f99 DH |
256 | struct cred *new; |
257 | int ret; | |
1da177e4 | 258 | |
d84f4f99 DH |
259 | new = prepare_creds(); |
260 | if (!new) | |
261 | return -ENOMEM; | |
1da177e4 | 262 | |
99599537 | 263 | ret = install_session_keyring_to_cred(new, keyring); |
d84f4f99 DH |
264 | if (ret < 0) { |
265 | abort_creds(new); | |
266 | return ret; | |
267 | } | |
1da177e4 | 268 | |
d84f4f99 DH |
269 | return commit_creds(new); |
270 | } | |
1da177e4 | 271 | |
1da177e4 | 272 | /* |
973c9f4f | 273 | * Handle the fsuid changing. |
1da177e4 LT |
274 | */ |
275 | void key_fsuid_changed(struct task_struct *tsk) | |
276 | { | |
277 | /* update the ownership of the thread keyring */ | |
b6dff3ec DH |
278 | BUG_ON(!tsk->cred); |
279 | if (tsk->cred->thread_keyring) { | |
280 | down_write(&tsk->cred->thread_keyring->sem); | |
281 | tsk->cred->thread_keyring->uid = tsk->cred->fsuid; | |
282 | up_write(&tsk->cred->thread_keyring->sem); | |
1da177e4 | 283 | } |
a8b17ed0 | 284 | } |
1da177e4 | 285 | |
1da177e4 | 286 | /* |
973c9f4f | 287 | * Handle the fsgid changing. |
1da177e4 LT |
288 | */ |
289 | void key_fsgid_changed(struct task_struct *tsk) | |
290 | { | |
291 | /* update the ownership of the thread keyring */ | |
b6dff3ec DH |
292 | BUG_ON(!tsk->cred); |
293 | if (tsk->cred->thread_keyring) { | |
294 | down_write(&tsk->cred->thread_keyring->sem); | |
295 | tsk->cred->thread_keyring->gid = tsk->cred->fsgid; | |
296 | up_write(&tsk->cred->thread_keyring->sem); | |
1da177e4 | 297 | } |
a8b17ed0 | 298 | } |
1da177e4 | 299 | |
1da177e4 | 300 | /* |
973c9f4f DH |
301 | * Search the process keyrings attached to the supplied cred for the first |
302 | * matching key. | |
303 | * | |
304 | * The search criteria are the type and the match function. The description is | |
305 | * given to the match function as a parameter, but doesn't otherwise influence | |
306 | * the search. Typically the match function will compare the description | |
307 | * parameter to the key's description. | |
308 | * | |
309 | * This can only search keyrings that grant Search permission to the supplied | |
310 | * credentials. Keyrings linked to searched keyrings will also be searched if | |
311 | * they grant Search permission too. Keys can only be found if they grant | |
312 | * Search permission to the credentials. | |
313 | * | |
314 | * Returns a pointer to the key with the key usage count incremented if | |
315 | * successful, -EAGAIN if we didn't find any matching key or -ENOKEY if we only | |
316 | * matched negative keys. | |
317 | * | |
318 | * In the case of a successful return, the possession attribute is set on the | |
319 | * returned key reference. | |
1da177e4 | 320 | */ |
927942aa DH |
321 | key_ref_t search_my_process_keyrings(struct key_type *type, |
322 | const void *description, | |
323 | key_match_func_t match, | |
78b7280c | 324 | bool no_state_check, |
927942aa | 325 | const struct cred *cred) |
1da177e4 | 326 | { |
b5f545c8 | 327 | key_ref_t key_ref, ret, err; |
1da177e4 LT |
328 | |
329 | /* we want to return -EAGAIN or -ENOKEY if any of the keyrings were | |
330 | * searchable, but we failed to find a key or we found a negative key; | |
331 | * otherwise we want to return a sample error (probably -EACCES) if | |
332 | * none of the keyrings were searchable | |
333 | * | |
334 | * in terms of priority: success > -ENOKEY > -EAGAIN > other error | |
335 | */ | |
664cceb0 | 336 | key_ref = NULL; |
1da177e4 LT |
337 | ret = NULL; |
338 | err = ERR_PTR(-EAGAIN); | |
339 | ||
340 | /* search the thread keyring first */ | |
c69e8d9c | 341 | if (cred->thread_keyring) { |
664cceb0 | 342 | key_ref = keyring_search_aux( |
c69e8d9c | 343 | make_key_ref(cred->thread_keyring, 1), |
78b7280c | 344 | cred, type, description, match, no_state_check); |
664cceb0 | 345 | if (!IS_ERR(key_ref)) |
1da177e4 LT |
346 | goto found; |
347 | ||
664cceb0 | 348 | switch (PTR_ERR(key_ref)) { |
1da177e4 | 349 | case -EAGAIN: /* no key */ |
1da177e4 | 350 | case -ENOKEY: /* negative key */ |
664cceb0 | 351 | ret = key_ref; |
1da177e4 LT |
352 | break; |
353 | default: | |
664cceb0 | 354 | err = key_ref; |
1da177e4 LT |
355 | break; |
356 | } | |
357 | } | |
358 | ||
359 | /* search the process keyring second */ | |
3a50597d | 360 | if (cred->process_keyring) { |
664cceb0 | 361 | key_ref = keyring_search_aux( |
3a50597d | 362 | make_key_ref(cred->process_keyring, 1), |
78b7280c | 363 | cred, type, description, match, no_state_check); |
664cceb0 | 364 | if (!IS_ERR(key_ref)) |
1da177e4 LT |
365 | goto found; |
366 | ||
664cceb0 | 367 | switch (PTR_ERR(key_ref)) { |
1da177e4 LT |
368 | case -EAGAIN: /* no key */ |
369 | if (ret) | |
370 | break; | |
371 | case -ENOKEY: /* negative key */ | |
664cceb0 | 372 | ret = key_ref; |
1da177e4 LT |
373 | break; |
374 | default: | |
664cceb0 | 375 | err = key_ref; |
1da177e4 LT |
376 | break; |
377 | } | |
378 | } | |
379 | ||
3e30148c | 380 | /* search the session keyring */ |
3a50597d | 381 | if (cred->session_keyring) { |
8589b4e0 | 382 | rcu_read_lock(); |
664cceb0 | 383 | key_ref = keyring_search_aux( |
3a50597d | 384 | make_key_ref(rcu_dereference(cred->session_keyring), 1), |
78b7280c | 385 | cred, type, description, match, no_state_check); |
8589b4e0 | 386 | rcu_read_unlock(); |
3e30148c | 387 | |
664cceb0 | 388 | if (!IS_ERR(key_ref)) |
3e30148c DH |
389 | goto found; |
390 | ||
664cceb0 | 391 | switch (PTR_ERR(key_ref)) { |
3e30148c DH |
392 | case -EAGAIN: /* no key */ |
393 | if (ret) | |
394 | break; | |
395 | case -ENOKEY: /* negative key */ | |
664cceb0 | 396 | ret = key_ref; |
3e30148c DH |
397 | break; |
398 | default: | |
664cceb0 | 399 | err = key_ref; |
3e30148c DH |
400 | break; |
401 | } | |
b5f545c8 DH |
402 | } |
403 | /* or search the user-session keyring */ | |
c69e8d9c | 404 | else if (cred->user->session_keyring) { |
b5f545c8 | 405 | key_ref = keyring_search_aux( |
c69e8d9c | 406 | make_key_ref(cred->user->session_keyring, 1), |
78b7280c | 407 | cred, type, description, match, no_state_check); |
664cceb0 | 408 | if (!IS_ERR(key_ref)) |
3e30148c DH |
409 | goto found; |
410 | ||
664cceb0 | 411 | switch (PTR_ERR(key_ref)) { |
3e30148c DH |
412 | case -EAGAIN: /* no key */ |
413 | if (ret) | |
414 | break; | |
415 | case -ENOKEY: /* negative key */ | |
664cceb0 | 416 | ret = key_ref; |
3e30148c DH |
417 | break; |
418 | default: | |
664cceb0 | 419 | err = key_ref; |
3e30148c DH |
420 | break; |
421 | } | |
8589b4e0 | 422 | } |
b5f545c8 | 423 | |
927942aa DH |
424 | /* no key - decide on the error we're going to go for */ |
425 | key_ref = ret ? ret : err; | |
426 | ||
427 | found: | |
428 | return key_ref; | |
429 | } | |
430 | ||
927942aa | 431 | /* |
973c9f4f DH |
432 | * Search the process keyrings attached to the supplied cred for the first |
433 | * matching key in the manner of search_my_process_keyrings(), but also search | |
434 | * the keys attached to the assumed authorisation key using its credentials if | |
435 | * one is available. | |
436 | * | |
437 | * Return same as search_my_process_keyrings(). | |
927942aa DH |
438 | */ |
439 | key_ref_t search_process_keyrings(struct key_type *type, | |
440 | const void *description, | |
441 | key_match_func_t match, | |
442 | const struct cred *cred) | |
443 | { | |
444 | struct request_key_auth *rka; | |
445 | key_ref_t key_ref, ret = ERR_PTR(-EACCES), err; | |
446 | ||
447 | might_sleep(); | |
448 | ||
78b7280c DH |
449 | key_ref = search_my_process_keyrings(type, description, match, |
450 | false, cred); | |
927942aa DH |
451 | if (!IS_ERR(key_ref)) |
452 | goto found; | |
453 | err = key_ref; | |
454 | ||
b5f545c8 DH |
455 | /* if this process has an instantiation authorisation key, then we also |
456 | * search the keyrings of the process mentioned there | |
457 | * - we don't permit access to request_key auth keys via this method | |
458 | */ | |
c69e8d9c | 459 | if (cred->request_key_auth && |
d84f4f99 | 460 | cred == current_cred() && |
04c567d9 | 461 | type != &key_type_request_key_auth |
b5f545c8 | 462 | ) { |
04c567d9 | 463 | /* defend against the auth key being revoked */ |
c69e8d9c | 464 | down_read(&cred->request_key_auth->sem); |
b5f545c8 | 465 | |
c69e8d9c DH |
466 | if (key_validate(cred->request_key_auth) == 0) { |
467 | rka = cred->request_key_auth->payload.data; | |
b5f545c8 | 468 | |
04c567d9 | 469 | key_ref = search_process_keyrings(type, description, |
d84f4f99 | 470 | match, rka->cred); |
1da177e4 | 471 | |
c69e8d9c | 472 | up_read(&cred->request_key_auth->sem); |
04c567d9 DH |
473 | |
474 | if (!IS_ERR(key_ref)) | |
475 | goto found; | |
476 | ||
927942aa | 477 | ret = key_ref; |
04c567d9 | 478 | } else { |
c69e8d9c | 479 | up_read(&cred->request_key_auth->sem); |
3e30148c | 480 | } |
1da177e4 LT |
481 | } |
482 | ||
483 | /* no key - decide on the error we're going to go for */ | |
927942aa DH |
484 | if (err == ERR_PTR(-ENOKEY) || ret == ERR_PTR(-ENOKEY)) |
485 | key_ref = ERR_PTR(-ENOKEY); | |
486 | else if (err == ERR_PTR(-EACCES)) | |
487 | key_ref = ret; | |
488 | else | |
489 | key_ref = err; | |
1da177e4 | 490 | |
3e30148c | 491 | found: |
664cceb0 | 492 | return key_ref; |
a8b17ed0 | 493 | } |
1da177e4 | 494 | |
664cceb0 | 495 | /* |
973c9f4f | 496 | * See if the key we're looking at is the target key. |
664cceb0 | 497 | */ |
927942aa | 498 | int lookup_user_key_possessed(const struct key *key, const void *target) |
664cceb0 DH |
499 | { |
500 | return key == target; | |
a8b17ed0 | 501 | } |
664cceb0 | 502 | |
1da177e4 | 503 | /* |
973c9f4f DH |
504 | * Look up a key ID given us by userspace with a given permissions mask to get |
505 | * the key it refers to. | |
506 | * | |
507 | * Flags can be passed to request that special keyrings be created if referred | |
508 | * to directly, to permit partially constructed keys to be found and to skip | |
509 | * validity and permission checks on the found key. | |
510 | * | |
511 | * Returns a pointer to the key with an incremented usage count if successful; | |
512 | * -EINVAL if the key ID is invalid; -ENOKEY if the key ID does not correspond | |
513 | * to a key or the best found key was a negative key; -EKEYREVOKED or | |
514 | * -EKEYEXPIRED if the best found key was revoked or expired; -EACCES if the | |
515 | * found key doesn't grant the requested permit or the LSM denied access to it; | |
516 | * or -ENOMEM if a special keyring couldn't be created. | |
517 | * | |
518 | * In the case of a successful return, the possession attribute is set on the | |
519 | * returned key reference. | |
1da177e4 | 520 | */ |
5593122e | 521 | key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags, |
8bbf4976 | 522 | key_perm_t perm) |
1da177e4 | 523 | { |
8bbf4976 | 524 | struct request_key_auth *rka; |
d84f4f99 | 525 | const struct cred *cred; |
1da177e4 | 526 | struct key *key; |
b6dff3ec | 527 | key_ref_t key_ref, skey_ref; |
1da177e4 LT |
528 | int ret; |
529 | ||
bb952bb9 DH |
530 | try_again: |
531 | cred = get_current_cred(); | |
664cceb0 | 532 | key_ref = ERR_PTR(-ENOKEY); |
1da177e4 LT |
533 | |
534 | switch (id) { | |
535 | case KEY_SPEC_THREAD_KEYRING: | |
b6dff3ec | 536 | if (!cred->thread_keyring) { |
5593122e | 537 | if (!(lflags & KEY_LOOKUP_CREATE)) |
1da177e4 LT |
538 | goto error; |
539 | ||
8bbf4976 | 540 | ret = install_thread_keyring(); |
1da177e4 | 541 | if (ret < 0) { |
4d09ec0f | 542 | key_ref = ERR_PTR(ret); |
1da177e4 LT |
543 | goto error; |
544 | } | |
bb952bb9 | 545 | goto reget_creds; |
1da177e4 LT |
546 | } |
547 | ||
b6dff3ec | 548 | key = cred->thread_keyring; |
1da177e4 | 549 | atomic_inc(&key->usage); |
664cceb0 | 550 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
551 | break; |
552 | ||
553 | case KEY_SPEC_PROCESS_KEYRING: | |
3a50597d | 554 | if (!cred->process_keyring) { |
5593122e | 555 | if (!(lflags & KEY_LOOKUP_CREATE)) |
1da177e4 LT |
556 | goto error; |
557 | ||
8bbf4976 | 558 | ret = install_process_keyring(); |
1da177e4 | 559 | if (ret < 0) { |
4d09ec0f | 560 | key_ref = ERR_PTR(ret); |
1da177e4 LT |
561 | goto error; |
562 | } | |
bb952bb9 | 563 | goto reget_creds; |
1da177e4 LT |
564 | } |
565 | ||
3a50597d | 566 | key = cred->process_keyring; |
1da177e4 | 567 | atomic_inc(&key->usage); |
664cceb0 | 568 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
569 | break; |
570 | ||
571 | case KEY_SPEC_SESSION_KEYRING: | |
3a50597d | 572 | if (!cred->session_keyring) { |
1da177e4 LT |
573 | /* always install a session keyring upon access if one |
574 | * doesn't exist yet */ | |
8bbf4976 | 575 | ret = install_user_keyrings(); |
69664cf1 DH |
576 | if (ret < 0) |
577 | goto error; | |
3ecf1b4f DH |
578 | if (lflags & KEY_LOOKUP_CREATE) |
579 | ret = join_session_keyring(NULL); | |
580 | else | |
581 | ret = install_session_keyring( | |
582 | cred->user->session_keyring); | |
d84f4f99 | 583 | |
1da177e4 LT |
584 | if (ret < 0) |
585 | goto error; | |
bb952bb9 | 586 | goto reget_creds; |
3a50597d | 587 | } else if (cred->session_keyring == |
3ecf1b4f DH |
588 | cred->user->session_keyring && |
589 | lflags & KEY_LOOKUP_CREATE) { | |
590 | ret = join_session_keyring(NULL); | |
591 | if (ret < 0) | |
592 | goto error; | |
593 | goto reget_creds; | |
1da177e4 LT |
594 | } |
595 | ||
3e30148c | 596 | rcu_read_lock(); |
3a50597d | 597 | key = rcu_dereference(cred->session_keyring); |
1da177e4 | 598 | atomic_inc(&key->usage); |
3e30148c | 599 | rcu_read_unlock(); |
664cceb0 | 600 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
601 | break; |
602 | ||
603 | case KEY_SPEC_USER_KEYRING: | |
b6dff3ec | 604 | if (!cred->user->uid_keyring) { |
8bbf4976 | 605 | ret = install_user_keyrings(); |
69664cf1 DH |
606 | if (ret < 0) |
607 | goto error; | |
608 | } | |
609 | ||
b6dff3ec | 610 | key = cred->user->uid_keyring; |
1da177e4 | 611 | atomic_inc(&key->usage); |
664cceb0 | 612 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
613 | break; |
614 | ||
615 | case KEY_SPEC_USER_SESSION_KEYRING: | |
b6dff3ec | 616 | if (!cred->user->session_keyring) { |
8bbf4976 | 617 | ret = install_user_keyrings(); |
69664cf1 DH |
618 | if (ret < 0) |
619 | goto error; | |
620 | } | |
621 | ||
b6dff3ec | 622 | key = cred->user->session_keyring; |
1da177e4 | 623 | atomic_inc(&key->usage); |
664cceb0 | 624 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
625 | break; |
626 | ||
627 | case KEY_SPEC_GROUP_KEYRING: | |
628 | /* group keyrings are not yet supported */ | |
4d09ec0f | 629 | key_ref = ERR_PTR(-EINVAL); |
1da177e4 LT |
630 | goto error; |
631 | ||
b5f545c8 | 632 | case KEY_SPEC_REQKEY_AUTH_KEY: |
b6dff3ec | 633 | key = cred->request_key_auth; |
b5f545c8 DH |
634 | if (!key) |
635 | goto error; | |
636 | ||
637 | atomic_inc(&key->usage); | |
638 | key_ref = make_key_ref(key, 1); | |
639 | break; | |
640 | ||
8bbf4976 | 641 | case KEY_SPEC_REQUESTOR_KEYRING: |
b6dff3ec | 642 | if (!cred->request_key_auth) |
8bbf4976 DH |
643 | goto error; |
644 | ||
b6dff3ec | 645 | down_read(&cred->request_key_auth->sem); |
f67dabbd DC |
646 | if (test_bit(KEY_FLAG_REVOKED, |
647 | &cred->request_key_auth->flags)) { | |
8bbf4976 DH |
648 | key_ref = ERR_PTR(-EKEYREVOKED); |
649 | key = NULL; | |
650 | } else { | |
b6dff3ec | 651 | rka = cred->request_key_auth->payload.data; |
8bbf4976 DH |
652 | key = rka->dest_keyring; |
653 | atomic_inc(&key->usage); | |
654 | } | |
b6dff3ec | 655 | up_read(&cred->request_key_auth->sem); |
8bbf4976 DH |
656 | if (!key) |
657 | goto error; | |
658 | key_ref = make_key_ref(key, 1); | |
659 | break; | |
660 | ||
1da177e4 | 661 | default: |
664cceb0 | 662 | key_ref = ERR_PTR(-EINVAL); |
1da177e4 LT |
663 | if (id < 1) |
664 | goto error; | |
665 | ||
666 | key = key_lookup(id); | |
664cceb0 | 667 | if (IS_ERR(key)) { |
e231c2ee | 668 | key_ref = ERR_CAST(key); |
1da177e4 | 669 | goto error; |
664cceb0 DH |
670 | } |
671 | ||
672 | key_ref = make_key_ref(key, 0); | |
673 | ||
674 | /* check to see if we possess the key */ | |
675 | skey_ref = search_process_keyrings(key->type, key, | |
676 | lookup_user_key_possessed, | |
d84f4f99 | 677 | cred); |
664cceb0 DH |
678 | |
679 | if (!IS_ERR(skey_ref)) { | |
680 | key_put(key); | |
681 | key_ref = skey_ref; | |
682 | } | |
683 | ||
1da177e4 LT |
684 | break; |
685 | } | |
686 | ||
5593122e DH |
687 | /* unlink does not use the nominated key in any way, so can skip all |
688 | * the permission checks as it is only concerned with the keyring */ | |
689 | if (lflags & KEY_LOOKUP_FOR_UNLINK) { | |
690 | ret = 0; | |
691 | goto error; | |
692 | } | |
693 | ||
694 | if (!(lflags & KEY_LOOKUP_PARTIAL)) { | |
76181c13 DH |
695 | ret = wait_for_key_construction(key, true); |
696 | switch (ret) { | |
697 | case -ERESTARTSYS: | |
698 | goto invalid_key; | |
699 | default: | |
700 | if (perm) | |
701 | goto invalid_key; | |
702 | case 0: | |
703 | break; | |
704 | } | |
705 | } else if (perm) { | |
1da177e4 LT |
706 | ret = key_validate(key); |
707 | if (ret < 0) | |
708 | goto invalid_key; | |
709 | } | |
710 | ||
711 | ret = -EIO; | |
5593122e DH |
712 | if (!(lflags & KEY_LOOKUP_PARTIAL) && |
713 | !test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) | |
1da177e4 LT |
714 | goto invalid_key; |
715 | ||
3e30148c | 716 | /* check the permissions */ |
d84f4f99 | 717 | ret = key_task_permission(key_ref, cred, perm); |
29db9190 | 718 | if (ret < 0) |
1da177e4 LT |
719 | goto invalid_key; |
720 | ||
31d5a79d DH |
721 | key->last_used_at = current_kernel_time().tv_sec; |
722 | ||
664cceb0 | 723 | error: |
bb952bb9 | 724 | put_cred(cred); |
664cceb0 | 725 | return key_ref; |
1da177e4 | 726 | |
664cceb0 DH |
727 | invalid_key: |
728 | key_ref_put(key_ref); | |
729 | key_ref = ERR_PTR(ret); | |
1da177e4 LT |
730 | goto error; |
731 | ||
bb952bb9 DH |
732 | /* if we attempted to install a keyring, then it may have caused new |
733 | * creds to be installed */ | |
734 | reget_creds: | |
735 | put_cred(cred); | |
736 | goto try_again; | |
a8b17ed0 | 737 | } |
bb952bb9 | 738 | |
1da177e4 | 739 | /* |
973c9f4f DH |
740 | * Join the named keyring as the session keyring if possible else attempt to |
741 | * create a new one of that name and join that. | |
742 | * | |
743 | * If the name is NULL, an empty anonymous keyring will be installed as the | |
744 | * session keyring. | |
745 | * | |
746 | * Named session keyrings are joined with a semaphore held to prevent the | |
747 | * keyrings from going away whilst the attempt is made to going them and also | |
748 | * to prevent a race in creating compatible session keyrings. | |
1da177e4 LT |
749 | */ |
750 | long join_session_keyring(const char *name) | |
751 | { | |
d84f4f99 DH |
752 | const struct cred *old; |
753 | struct cred *new; | |
1da177e4 | 754 | struct key *keyring; |
d84f4f99 DH |
755 | long ret, serial; |
756 | ||
d84f4f99 DH |
757 | new = prepare_creds(); |
758 | if (!new) | |
759 | return -ENOMEM; | |
760 | old = current_cred(); | |
1da177e4 LT |
761 | |
762 | /* if no name is provided, install an anonymous keyring */ | |
763 | if (!name) { | |
d84f4f99 | 764 | ret = install_session_keyring_to_cred(new, NULL); |
1da177e4 LT |
765 | if (ret < 0) |
766 | goto error; | |
767 | ||
3a50597d | 768 | serial = new->session_keyring->serial; |
d84f4f99 DH |
769 | ret = commit_creds(new); |
770 | if (ret == 0) | |
771 | ret = serial; | |
772 | goto okay; | |
1da177e4 LT |
773 | } |
774 | ||
775 | /* allow the user to join or create a named keyring */ | |
bb003079 | 776 | mutex_lock(&key_session_mutex); |
1da177e4 LT |
777 | |
778 | /* look for an existing keyring of this name */ | |
69664cf1 | 779 | keyring = find_keyring_by_name(name, false); |
1da177e4 LT |
780 | if (PTR_ERR(keyring) == -ENOKEY) { |
781 | /* not found - try and create a new one */ | |
96b5c8fe DH |
782 | keyring = keyring_alloc( |
783 | name, old->uid, old->gid, old, | |
784 | KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_LINK, | |
785 | KEY_ALLOC_IN_QUOTA, NULL); | |
1da177e4 LT |
786 | if (IS_ERR(keyring)) { |
787 | ret = PTR_ERR(keyring); | |
bcf945d3 | 788 | goto error2; |
1da177e4 | 789 | } |
d84f4f99 | 790 | } else if (IS_ERR(keyring)) { |
1da177e4 LT |
791 | ret = PTR_ERR(keyring); |
792 | goto error2; | |
3a50597d DH |
793 | } else if (keyring == new->session_keyring) { |
794 | ret = 0; | |
795 | goto error2; | |
1da177e4 LT |
796 | } |
797 | ||
798 | /* we've got a keyring - now to install it */ | |
d84f4f99 | 799 | ret = install_session_keyring_to_cred(new, keyring); |
1da177e4 LT |
800 | if (ret < 0) |
801 | goto error2; | |
802 | ||
d84f4f99 DH |
803 | commit_creds(new); |
804 | mutex_unlock(&key_session_mutex); | |
805 | ||
1da177e4 LT |
806 | ret = keyring->serial; |
807 | key_put(keyring); | |
d84f4f99 DH |
808 | okay: |
809 | return ret; | |
1da177e4 | 810 | |
664cceb0 | 811 | error2: |
bb003079 | 812 | mutex_unlock(&key_session_mutex); |
664cceb0 | 813 | error: |
d84f4f99 | 814 | abort_creds(new); |
1da177e4 | 815 | return ret; |
d84f4f99 | 816 | } |
ee18d64c DH |
817 | |
818 | /* | |
973c9f4f DH |
819 | * Replace a process's session keyring on behalf of one of its children when |
820 | * the target process is about to resume userspace execution. | |
ee18d64c | 821 | */ |
67d12145 | 822 | void key_change_session_keyring(struct callback_head *twork) |
ee18d64c | 823 | { |
413cd3d9 | 824 | const struct cred *old = current_cred(); |
67d12145 | 825 | struct cred *new = container_of(twork, struct cred, rcu); |
ee18d64c | 826 | |
413cd3d9 ON |
827 | if (unlikely(current->flags & PF_EXITING)) { |
828 | put_cred(new); | |
ee18d64c | 829 | return; |
413cd3d9 | 830 | } |
ee18d64c | 831 | |
ee18d64c DH |
832 | new-> uid = old-> uid; |
833 | new-> euid = old-> euid; | |
834 | new-> suid = old-> suid; | |
835 | new->fsuid = old->fsuid; | |
836 | new-> gid = old-> gid; | |
837 | new-> egid = old-> egid; | |
838 | new-> sgid = old-> sgid; | |
839 | new->fsgid = old->fsgid; | |
840 | new->user = get_uid(old->user); | |
0093ccb6 | 841 | new->user_ns = get_user_ns(new->user_ns); |
ee18d64c DH |
842 | new->group_info = get_group_info(old->group_info); |
843 | ||
844 | new->securebits = old->securebits; | |
845 | new->cap_inheritable = old->cap_inheritable; | |
846 | new->cap_permitted = old->cap_permitted; | |
847 | new->cap_effective = old->cap_effective; | |
848 | new->cap_bset = old->cap_bset; | |
849 | ||
850 | new->jit_keyring = old->jit_keyring; | |
851 | new->thread_keyring = key_get(old->thread_keyring); | |
3a50597d | 852 | new->process_keyring = key_get(old->process_keyring); |
ee18d64c DH |
853 | |
854 | security_transfer_creds(new, old); | |
855 | ||
856 | commit_creds(new); | |
857 | } |