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Commit | Line | Data |
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69664cf1 | 1 | /* Management of 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 | ||
24 | /* session keyring create vs join semaphore */ | |
bb003079 | 25 | static DEFINE_MUTEX(key_session_mutex); |
1da177e4 | 26 | |
69664cf1 DH |
27 | /* user keyring creation semaphore */ |
28 | static DEFINE_MUTEX(key_user_keyring_mutex); | |
29 | ||
1da177e4 LT |
30 | /* the root user's tracking struct */ |
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 LT |
41 | /*****************************************************************************/ |
42 | /* | |
69664cf1 | 43 | * install user and user session keyrings for a particular UID |
1da177e4 | 44 | */ |
8bbf4976 | 45 | int install_user_keyrings(void) |
1da177e4 | 46 | { |
d84f4f99 DH |
47 | struct user_struct *user; |
48 | const struct cred *cred; | |
1da177e4 LT |
49 | struct key *uid_keyring, *session_keyring; |
50 | char buf[20]; | |
51 | int ret; | |
52 | ||
d84f4f99 DH |
53 | cred = current_cred(); |
54 | user = cred->user; | |
55 | ||
69664cf1 | 56 | kenter("%p{%u}", user, user->uid); |
1da177e4 | 57 | |
69664cf1 DH |
58 | if (user->uid_keyring) { |
59 | kleave(" = 0 [exist]"); | |
60 | return 0; | |
1da177e4 LT |
61 | } |
62 | ||
69664cf1 DH |
63 | mutex_lock(&key_user_keyring_mutex); |
64 | ret = 0; | |
1da177e4 | 65 | |
69664cf1 DH |
66 | if (!user->uid_keyring) { |
67 | /* get the UID-specific keyring | |
68 | * - there may be one in existence already as it may have been | |
69 | * pinned by a session, but the user_struct pointing to it | |
70 | * may have been destroyed by setuid */ | |
71 | sprintf(buf, "_uid.%u", user->uid); | |
72 | ||
73 | uid_keyring = find_keyring_by_name(buf, true); | |
74 | if (IS_ERR(uid_keyring)) { | |
75 | uid_keyring = keyring_alloc(buf, user->uid, (gid_t) -1, | |
d84f4f99 | 76 | cred, KEY_ALLOC_IN_QUOTA, |
69664cf1 DH |
77 | NULL); |
78 | if (IS_ERR(uid_keyring)) { | |
79 | ret = PTR_ERR(uid_keyring); | |
80 | goto error; | |
81 | } | |
82 | } | |
83 | ||
84 | /* get a default session keyring (which might also exist | |
85 | * already) */ | |
86 | sprintf(buf, "_uid_ses.%u", user->uid); | |
87 | ||
88 | session_keyring = find_keyring_by_name(buf, true); | |
89 | if (IS_ERR(session_keyring)) { | |
90 | session_keyring = | |
91 | keyring_alloc(buf, user->uid, (gid_t) -1, | |
d84f4f99 | 92 | cred, KEY_ALLOC_IN_QUOTA, NULL); |
69664cf1 DH |
93 | if (IS_ERR(session_keyring)) { |
94 | ret = PTR_ERR(session_keyring); | |
95 | goto error_release; | |
96 | } | |
97 | ||
98 | /* we install a link from the user session keyring to | |
99 | * the user keyring */ | |
100 | ret = key_link(session_keyring, uid_keyring); | |
101 | if (ret < 0) | |
102 | goto error_release_both; | |
103 | } | |
104 | ||
105 | /* install the keyrings */ | |
106 | user->uid_keyring = uid_keyring; | |
107 | user->session_keyring = session_keyring; | |
1da177e4 LT |
108 | } |
109 | ||
69664cf1 DH |
110 | mutex_unlock(&key_user_keyring_mutex); |
111 | kleave(" = 0"); | |
112 | return 0; | |
1da177e4 | 113 | |
69664cf1 DH |
114 | error_release_both: |
115 | key_put(session_keyring); | |
116 | error_release: | |
117 | key_put(uid_keyring); | |
664cceb0 | 118 | error: |
69664cf1 DH |
119 | mutex_unlock(&key_user_keyring_mutex); |
120 | kleave(" = %d", ret); | |
1da177e4 | 121 | return ret; |
69664cf1 | 122 | } |
1da177e4 | 123 | |
1da177e4 | 124 | /* |
d84f4f99 | 125 | * install a fresh thread keyring directly to new credentials |
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 LT |
140 | /* |
141 | * install a fresh thread keyring, discarding the old one | |
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 DH |
163 | /* |
164 | * install a process keyring directly to a credentials struct | |
165 | * - returns -EEXIST if there was already a process keyring, 0 if one installed, | |
166 | * and other -ve on any other error | |
167 | */ | |
168 | int install_process_keyring_to_cred(struct cred *new) | |
169 | { | |
170 | struct key *keyring; | |
171 | int ret; | |
1da177e4 | 172 | |
d84f4f99 DH |
173 | if (new->tgcred->process_keyring) |
174 | return -EEXIST; | |
175 | ||
176 | keyring = keyring_alloc("_pid", new->uid, new->gid, | |
177 | new, KEY_ALLOC_QUOTA_OVERRUN, NULL); | |
178 | if (IS_ERR(keyring)) | |
179 | return PTR_ERR(keyring); | |
180 | ||
181 | spin_lock_irq(&new->tgcred->lock); | |
182 | if (!new->tgcred->process_keyring) { | |
183 | new->tgcred->process_keyring = keyring; | |
184 | keyring = NULL; | |
185 | ret = 0; | |
186 | } else { | |
187 | ret = -EEXIST; | |
188 | } | |
189 | spin_unlock_irq(&new->tgcred->lock); | |
190 | key_put(keyring); | |
1da177e4 | 191 | return ret; |
d84f4f99 | 192 | } |
1da177e4 | 193 | |
1da177e4 LT |
194 | /* |
195 | * make sure a process keyring is installed | |
d84f4f99 | 196 | * - we |
1da177e4 | 197 | */ |
d84f4f99 | 198 | static int install_process_keyring(void) |
1da177e4 | 199 | { |
d84f4f99 | 200 | struct cred *new; |
1da177e4 LT |
201 | int ret; |
202 | ||
d84f4f99 DH |
203 | new = prepare_creds(); |
204 | if (!new) | |
205 | return -ENOMEM; | |
1da177e4 | 206 | |
d84f4f99 DH |
207 | ret = install_process_keyring_to_cred(new); |
208 | if (ret < 0) { | |
209 | abort_creds(new); | |
210 | return ret != -EEXIST ?: 0; | |
1da177e4 LT |
211 | } |
212 | ||
d84f4f99 DH |
213 | return commit_creds(new); |
214 | } | |
1da177e4 | 215 | |
1da177e4 | 216 | /* |
d84f4f99 | 217 | * install a session keyring directly to a credentials struct |
1da177e4 | 218 | */ |
d84f4f99 DH |
219 | static int install_session_keyring_to_cred(struct cred *cred, |
220 | struct key *keyring) | |
1da177e4 | 221 | { |
7e047ef5 | 222 | unsigned long flags; |
1da177e4 | 223 | struct key *old; |
1a26feb9 DH |
224 | |
225 | might_sleep(); | |
1da177e4 LT |
226 | |
227 | /* create an empty session keyring */ | |
228 | if (!keyring) { | |
7e047ef5 | 229 | flags = KEY_ALLOC_QUOTA_OVERRUN; |
d84f4f99 | 230 | if (cred->tgcred->session_keyring) |
7e047ef5 DH |
231 | flags = KEY_ALLOC_IN_QUOTA; |
232 | ||
d84f4f99 DH |
233 | keyring = keyring_alloc("_ses", cred->uid, cred->gid, |
234 | cred, flags, NULL); | |
1a26feb9 DH |
235 | if (IS_ERR(keyring)) |
236 | return PTR_ERR(keyring); | |
d84f4f99 | 237 | } else { |
1da177e4 LT |
238 | atomic_inc(&keyring->usage); |
239 | } | |
240 | ||
241 | /* install the keyring */ | |
d84f4f99 DH |
242 | spin_lock_irq(&cred->tgcred->lock); |
243 | old = cred->tgcred->session_keyring; | |
244 | rcu_assign_pointer(cred->tgcred->session_keyring, keyring); | |
245 | spin_unlock_irq(&cred->tgcred->lock); | |
1da177e4 | 246 | |
1a26feb9 DH |
247 | /* we're using RCU on the pointer, but there's no point synchronising |
248 | * on it if it didn't previously point to anything */ | |
249 | if (old) { | |
250 | synchronize_rcu(); | |
251 | key_put(old); | |
252 | } | |
1da177e4 | 253 | |
1a26feb9 | 254 | return 0; |
d84f4f99 | 255 | } |
1da177e4 | 256 | |
1da177e4 | 257 | /* |
d84f4f99 DH |
258 | * install a session keyring, discarding the old one |
259 | * - if a keyring is not supplied, an empty one is invented | |
1da177e4 | 260 | */ |
d84f4f99 | 261 | static int install_session_keyring(struct key *keyring) |
1da177e4 | 262 | { |
d84f4f99 DH |
263 | struct cred *new; |
264 | int ret; | |
1da177e4 | 265 | |
d84f4f99 DH |
266 | new = prepare_creds(); |
267 | if (!new) | |
268 | return -ENOMEM; | |
1da177e4 | 269 | |
d84f4f99 DH |
270 | ret = install_session_keyring_to_cred(new, NULL); |
271 | if (ret < 0) { | |
272 | abort_creds(new); | |
273 | return ret; | |
274 | } | |
1da177e4 | 275 | |
d84f4f99 DH |
276 | return commit_creds(new); |
277 | } | |
1da177e4 | 278 | |
1da177e4 LT |
279 | /*****************************************************************************/ |
280 | /* | |
281 | * the filesystem user ID changed | |
282 | */ | |
283 | void key_fsuid_changed(struct task_struct *tsk) | |
284 | { | |
285 | /* update the ownership of the thread keyring */ | |
b6dff3ec DH |
286 | BUG_ON(!tsk->cred); |
287 | if (tsk->cred->thread_keyring) { | |
288 | down_write(&tsk->cred->thread_keyring->sem); | |
289 | tsk->cred->thread_keyring->uid = tsk->cred->fsuid; | |
290 | up_write(&tsk->cred->thread_keyring->sem); | |
1da177e4 LT |
291 | } |
292 | ||
293 | } /* end key_fsuid_changed() */ | |
294 | ||
295 | /*****************************************************************************/ | |
296 | /* | |
297 | * the filesystem group ID changed | |
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 LT |
307 | } |
308 | ||
309 | } /* end key_fsgid_changed() */ | |
310 | ||
311 | /*****************************************************************************/ | |
312 | /* | |
313 | * search the process keyrings for the first matching key | |
314 | * - we use the supplied match function to see if the description (or other | |
315 | * feature of interest) matches | |
316 | * - we return -EAGAIN if we didn't find any matching key | |
317 | * - we return -ENOKEY if we found only negative matching keys | |
318 | */ | |
664cceb0 DH |
319 | key_ref_t search_process_keyrings(struct key_type *type, |
320 | const void *description, | |
321 | key_match_func_t match, | |
d84f4f99 | 322 | const struct cred *cred) |
1da177e4 | 323 | { |
3e30148c | 324 | struct request_key_auth *rka; |
b5f545c8 | 325 | key_ref_t key_ref, ret, err; |
1da177e4 | 326 | |
04c567d9 DH |
327 | might_sleep(); |
328 | ||
1da177e4 LT |
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), |
d84f4f99 | 344 | cred, type, description, match); |
664cceb0 | 345 | if (!IS_ERR(key_ref)) |
1da177e4 LT |
346 | goto found; |
347 | ||
664cceb0 | 348 | switch (PTR_ERR(key_ref)) { |
1da177e4 LT |
349 | case -EAGAIN: /* no key */ |
350 | if (ret) | |
351 | break; | |
352 | case -ENOKEY: /* negative key */ | |
664cceb0 | 353 | ret = key_ref; |
1da177e4 LT |
354 | break; |
355 | default: | |
664cceb0 | 356 | err = key_ref; |
1da177e4 LT |
357 | break; |
358 | } | |
359 | } | |
360 | ||
361 | /* search the process keyring second */ | |
bb952bb9 | 362 | if (cred->tgcred->process_keyring) { |
664cceb0 | 363 | key_ref = keyring_search_aux( |
bb952bb9 | 364 | make_key_ref(cred->tgcred->process_keyring, 1), |
d84f4f99 | 365 | cred, type, description, match); |
664cceb0 | 366 | if (!IS_ERR(key_ref)) |
1da177e4 LT |
367 | goto found; |
368 | ||
664cceb0 | 369 | switch (PTR_ERR(key_ref)) { |
1da177e4 LT |
370 | case -EAGAIN: /* no key */ |
371 | if (ret) | |
372 | break; | |
373 | case -ENOKEY: /* negative key */ | |
664cceb0 | 374 | ret = key_ref; |
1da177e4 LT |
375 | break; |
376 | default: | |
664cceb0 | 377 | err = key_ref; |
1da177e4 LT |
378 | break; |
379 | } | |
380 | } | |
381 | ||
3e30148c | 382 | /* search the session keyring */ |
bb952bb9 | 383 | if (cred->tgcred->session_keyring) { |
8589b4e0 | 384 | rcu_read_lock(); |
664cceb0 DH |
385 | key_ref = keyring_search_aux( |
386 | make_key_ref(rcu_dereference( | |
bb952bb9 | 387 | cred->tgcred->session_keyring), |
664cceb0 | 388 | 1), |
d84f4f99 | 389 | cred, type, description, match); |
8589b4e0 | 390 | rcu_read_unlock(); |
3e30148c | 391 | |
664cceb0 | 392 | if (!IS_ERR(key_ref)) |
3e30148c DH |
393 | goto found; |
394 | ||
664cceb0 | 395 | switch (PTR_ERR(key_ref)) { |
3e30148c DH |
396 | case -EAGAIN: /* no key */ |
397 | if (ret) | |
398 | break; | |
399 | case -ENOKEY: /* negative key */ | |
664cceb0 | 400 | ret = key_ref; |
3e30148c DH |
401 | break; |
402 | default: | |
664cceb0 | 403 | err = key_ref; |
3e30148c DH |
404 | break; |
405 | } | |
b5f545c8 DH |
406 | } |
407 | /* or search the user-session keyring */ | |
c69e8d9c | 408 | else if (cred->user->session_keyring) { |
b5f545c8 | 409 | key_ref = keyring_search_aux( |
c69e8d9c | 410 | make_key_ref(cred->user->session_keyring, 1), |
d84f4f99 | 411 | cred, type, description, match); |
664cceb0 | 412 | if (!IS_ERR(key_ref)) |
3e30148c DH |
413 | goto found; |
414 | ||
664cceb0 | 415 | switch (PTR_ERR(key_ref)) { |
3e30148c DH |
416 | case -EAGAIN: /* no key */ |
417 | if (ret) | |
418 | break; | |
419 | case -ENOKEY: /* negative key */ | |
664cceb0 | 420 | ret = key_ref; |
3e30148c DH |
421 | break; |
422 | default: | |
664cceb0 | 423 | err = key_ref; |
3e30148c DH |
424 | break; |
425 | } | |
8589b4e0 | 426 | } |
b5f545c8 DH |
427 | |
428 | /* if this process has an instantiation authorisation key, then we also | |
429 | * search the keyrings of the process mentioned there | |
430 | * - we don't permit access to request_key auth keys via this method | |
431 | */ | |
c69e8d9c | 432 | if (cred->request_key_auth && |
d84f4f99 | 433 | cred == current_cred() && |
04c567d9 | 434 | type != &key_type_request_key_auth |
b5f545c8 | 435 | ) { |
04c567d9 | 436 | /* defend against the auth key being revoked */ |
c69e8d9c | 437 | down_read(&cred->request_key_auth->sem); |
b5f545c8 | 438 | |
c69e8d9c DH |
439 | if (key_validate(cred->request_key_auth) == 0) { |
440 | rka = cred->request_key_auth->payload.data; | |
b5f545c8 | 441 | |
04c567d9 | 442 | key_ref = search_process_keyrings(type, description, |
d84f4f99 | 443 | match, rka->cred); |
1da177e4 | 444 | |
c69e8d9c | 445 | up_read(&cred->request_key_auth->sem); |
04c567d9 DH |
446 | |
447 | if (!IS_ERR(key_ref)) | |
448 | goto found; | |
449 | ||
450 | switch (PTR_ERR(key_ref)) { | |
451 | case -EAGAIN: /* no key */ | |
452 | if (ret) | |
453 | break; | |
454 | case -ENOKEY: /* negative key */ | |
455 | ret = key_ref; | |
3e30148c | 456 | break; |
04c567d9 DH |
457 | default: |
458 | err = key_ref; | |
459 | break; | |
460 | } | |
461 | } else { | |
c69e8d9c | 462 | up_read(&cred->request_key_auth->sem); |
3e30148c | 463 | } |
1da177e4 LT |
464 | } |
465 | ||
466 | /* no key - decide on the error we're going to go for */ | |
664cceb0 | 467 | key_ref = ret ? ret : err; |
1da177e4 | 468 | |
3e30148c | 469 | found: |
664cceb0 | 470 | return key_ref; |
1da177e4 | 471 | |
1da177e4 LT |
472 | } /* end search_process_keyrings() */ |
473 | ||
664cceb0 DH |
474 | /*****************************************************************************/ |
475 | /* | |
476 | * see if the key we're looking at is the target key | |
477 | */ | |
478 | static int lookup_user_key_possessed(const struct key *key, const void *target) | |
479 | { | |
480 | return key == target; | |
481 | ||
482 | } /* end lookup_user_key_possessed() */ | |
483 | ||
1da177e4 LT |
484 | /*****************************************************************************/ |
485 | /* | |
486 | * lookup a key given a key ID from userspace with a given permissions mask | |
487 | * - don't create special keyrings unless so requested | |
488 | * - partially constructed keys aren't found unless requested | |
489 | */ | |
5593122e | 490 | key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags, |
8bbf4976 | 491 | key_perm_t perm) |
1da177e4 | 492 | { |
8bbf4976 | 493 | struct request_key_auth *rka; |
d84f4f99 | 494 | const struct cred *cred; |
1da177e4 | 495 | struct key *key; |
b6dff3ec | 496 | key_ref_t key_ref, skey_ref; |
1da177e4 LT |
497 | int ret; |
498 | ||
bb952bb9 DH |
499 | try_again: |
500 | cred = get_current_cred(); | |
664cceb0 | 501 | key_ref = ERR_PTR(-ENOKEY); |
1da177e4 LT |
502 | |
503 | switch (id) { | |
504 | case KEY_SPEC_THREAD_KEYRING: | |
b6dff3ec | 505 | if (!cred->thread_keyring) { |
5593122e | 506 | if (!(lflags & KEY_LOOKUP_CREATE)) |
1da177e4 LT |
507 | goto error; |
508 | ||
8bbf4976 | 509 | ret = install_thread_keyring(); |
1da177e4 | 510 | if (ret < 0) { |
4d09ec0f | 511 | key_ref = ERR_PTR(ret); |
1da177e4 LT |
512 | goto error; |
513 | } | |
bb952bb9 | 514 | goto reget_creds; |
1da177e4 LT |
515 | } |
516 | ||
b6dff3ec | 517 | key = cred->thread_keyring; |
1da177e4 | 518 | atomic_inc(&key->usage); |
664cceb0 | 519 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
520 | break; |
521 | ||
522 | case KEY_SPEC_PROCESS_KEYRING: | |
bb952bb9 | 523 | if (!cred->tgcred->process_keyring) { |
5593122e | 524 | if (!(lflags & KEY_LOOKUP_CREATE)) |
1da177e4 LT |
525 | goto error; |
526 | ||
8bbf4976 | 527 | ret = install_process_keyring(); |
1da177e4 | 528 | if (ret < 0) { |
4d09ec0f | 529 | key_ref = ERR_PTR(ret); |
1da177e4 LT |
530 | goto error; |
531 | } | |
bb952bb9 | 532 | goto reget_creds; |
1da177e4 LT |
533 | } |
534 | ||
bb952bb9 | 535 | key = cred->tgcred->process_keyring; |
1da177e4 | 536 | atomic_inc(&key->usage); |
664cceb0 | 537 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
538 | break; |
539 | ||
540 | case KEY_SPEC_SESSION_KEYRING: | |
bb952bb9 | 541 | if (!cred->tgcred->session_keyring) { |
1da177e4 LT |
542 | /* always install a session keyring upon access if one |
543 | * doesn't exist yet */ | |
8bbf4976 | 544 | ret = install_user_keyrings(); |
69664cf1 DH |
545 | if (ret < 0) |
546 | goto error; | |
b6dff3ec DH |
547 | ret = install_session_keyring( |
548 | cred->user->session_keyring); | |
d84f4f99 | 549 | |
1da177e4 LT |
550 | if (ret < 0) |
551 | goto error; | |
bb952bb9 | 552 | goto reget_creds; |
1da177e4 LT |
553 | } |
554 | ||
3e30148c | 555 | rcu_read_lock(); |
bb952bb9 | 556 | key = rcu_dereference(cred->tgcred->session_keyring); |
1da177e4 | 557 | atomic_inc(&key->usage); |
3e30148c | 558 | rcu_read_unlock(); |
664cceb0 | 559 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
560 | break; |
561 | ||
562 | case KEY_SPEC_USER_KEYRING: | |
b6dff3ec | 563 | if (!cred->user->uid_keyring) { |
8bbf4976 | 564 | ret = install_user_keyrings(); |
69664cf1 DH |
565 | if (ret < 0) |
566 | goto error; | |
567 | } | |
568 | ||
b6dff3ec | 569 | key = cred->user->uid_keyring; |
1da177e4 | 570 | atomic_inc(&key->usage); |
664cceb0 | 571 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
572 | break; |
573 | ||
574 | case KEY_SPEC_USER_SESSION_KEYRING: | |
b6dff3ec | 575 | if (!cred->user->session_keyring) { |
8bbf4976 | 576 | ret = install_user_keyrings(); |
69664cf1 DH |
577 | if (ret < 0) |
578 | goto error; | |
579 | } | |
580 | ||
b6dff3ec | 581 | key = cred->user->session_keyring; |
1da177e4 | 582 | atomic_inc(&key->usage); |
664cceb0 | 583 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
584 | break; |
585 | ||
586 | case KEY_SPEC_GROUP_KEYRING: | |
587 | /* group keyrings are not yet supported */ | |
4d09ec0f | 588 | key_ref = ERR_PTR(-EINVAL); |
1da177e4 LT |
589 | goto error; |
590 | ||
b5f545c8 | 591 | case KEY_SPEC_REQKEY_AUTH_KEY: |
b6dff3ec | 592 | key = cred->request_key_auth; |
b5f545c8 DH |
593 | if (!key) |
594 | goto error; | |
595 | ||
596 | atomic_inc(&key->usage); | |
597 | key_ref = make_key_ref(key, 1); | |
598 | break; | |
599 | ||
8bbf4976 | 600 | case KEY_SPEC_REQUESTOR_KEYRING: |
b6dff3ec | 601 | if (!cred->request_key_auth) |
8bbf4976 DH |
602 | goto error; |
603 | ||
b6dff3ec DH |
604 | down_read(&cred->request_key_auth->sem); |
605 | if (cred->request_key_auth->flags & KEY_FLAG_REVOKED) { | |
8bbf4976 DH |
606 | key_ref = ERR_PTR(-EKEYREVOKED); |
607 | key = NULL; | |
608 | } else { | |
b6dff3ec | 609 | rka = cred->request_key_auth->payload.data; |
8bbf4976 DH |
610 | key = rka->dest_keyring; |
611 | atomic_inc(&key->usage); | |
612 | } | |
b6dff3ec | 613 | up_read(&cred->request_key_auth->sem); |
8bbf4976 DH |
614 | if (!key) |
615 | goto error; | |
616 | key_ref = make_key_ref(key, 1); | |
617 | break; | |
618 | ||
1da177e4 | 619 | default: |
664cceb0 | 620 | key_ref = ERR_PTR(-EINVAL); |
1da177e4 LT |
621 | if (id < 1) |
622 | goto error; | |
623 | ||
624 | key = key_lookup(id); | |
664cceb0 | 625 | if (IS_ERR(key)) { |
e231c2ee | 626 | key_ref = ERR_CAST(key); |
1da177e4 | 627 | goto error; |
664cceb0 DH |
628 | } |
629 | ||
630 | key_ref = make_key_ref(key, 0); | |
631 | ||
632 | /* check to see if we possess the key */ | |
633 | skey_ref = search_process_keyrings(key->type, key, | |
634 | lookup_user_key_possessed, | |
d84f4f99 | 635 | cred); |
664cceb0 DH |
636 | |
637 | if (!IS_ERR(skey_ref)) { | |
638 | key_put(key); | |
639 | key_ref = skey_ref; | |
640 | } | |
641 | ||
1da177e4 LT |
642 | break; |
643 | } | |
644 | ||
5593122e DH |
645 | /* unlink does not use the nominated key in any way, so can skip all |
646 | * the permission checks as it is only concerned with the keyring */ | |
647 | if (lflags & KEY_LOOKUP_FOR_UNLINK) { | |
648 | ret = 0; | |
649 | goto error; | |
650 | } | |
651 | ||
652 | if (!(lflags & KEY_LOOKUP_PARTIAL)) { | |
76181c13 DH |
653 | ret = wait_for_key_construction(key, true); |
654 | switch (ret) { | |
655 | case -ERESTARTSYS: | |
656 | goto invalid_key; | |
657 | default: | |
658 | if (perm) | |
659 | goto invalid_key; | |
660 | case 0: | |
661 | break; | |
662 | } | |
663 | } else if (perm) { | |
1da177e4 LT |
664 | ret = key_validate(key); |
665 | if (ret < 0) | |
666 | goto invalid_key; | |
667 | } | |
668 | ||
669 | ret = -EIO; | |
5593122e DH |
670 | if (!(lflags & KEY_LOOKUP_PARTIAL) && |
671 | !test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) | |
1da177e4 LT |
672 | goto invalid_key; |
673 | ||
3e30148c | 674 | /* check the permissions */ |
d84f4f99 | 675 | ret = key_task_permission(key_ref, cred, perm); |
29db9190 | 676 | if (ret < 0) |
1da177e4 LT |
677 | goto invalid_key; |
678 | ||
664cceb0 | 679 | error: |
bb952bb9 | 680 | put_cred(cred); |
664cceb0 | 681 | return key_ref; |
1da177e4 | 682 | |
664cceb0 DH |
683 | invalid_key: |
684 | key_ref_put(key_ref); | |
685 | key_ref = ERR_PTR(ret); | |
1da177e4 LT |
686 | goto error; |
687 | ||
bb952bb9 DH |
688 | /* if we attempted to install a keyring, then it may have caused new |
689 | * creds to be installed */ | |
690 | reget_creds: | |
691 | put_cred(cred); | |
692 | goto try_again; | |
693 | ||
1da177e4 LT |
694 | } /* end lookup_user_key() */ |
695 | ||
696 | /*****************************************************************************/ | |
697 | /* | |
698 | * join the named keyring as the session keyring if possible, or attempt to | |
699 | * create a new one of that name if not | |
700 | * - if the name is NULL, an empty anonymous keyring is installed instead | |
701 | * - named session keyring joining is done with a semaphore held | |
702 | */ | |
703 | long join_session_keyring(const char *name) | |
704 | { | |
d84f4f99 DH |
705 | const struct cred *old; |
706 | struct cred *new; | |
1da177e4 | 707 | struct key *keyring; |
d84f4f99 DH |
708 | long ret, serial; |
709 | ||
710 | /* only permit this if there's a single thread in the thread group - | |
711 | * this avoids us having to adjust the creds on all threads and risking | |
712 | * ENOMEM */ | |
5bb459bb | 713 | if (!current_is_single_threaded()) |
d84f4f99 DH |
714 | return -EMLINK; |
715 | ||
716 | new = prepare_creds(); | |
717 | if (!new) | |
718 | return -ENOMEM; | |
719 | old = current_cred(); | |
1da177e4 LT |
720 | |
721 | /* if no name is provided, install an anonymous keyring */ | |
722 | if (!name) { | |
d84f4f99 | 723 | ret = install_session_keyring_to_cred(new, NULL); |
1da177e4 LT |
724 | if (ret < 0) |
725 | goto error; | |
726 | ||
d84f4f99 DH |
727 | serial = new->tgcred->session_keyring->serial; |
728 | ret = commit_creds(new); | |
729 | if (ret == 0) | |
730 | ret = serial; | |
731 | goto okay; | |
1da177e4 LT |
732 | } |
733 | ||
734 | /* allow the user to join or create a named keyring */ | |
bb003079 | 735 | mutex_lock(&key_session_mutex); |
1da177e4 LT |
736 | |
737 | /* look for an existing keyring of this name */ | |
69664cf1 | 738 | keyring = find_keyring_by_name(name, false); |
1da177e4 LT |
739 | if (PTR_ERR(keyring) == -ENOKEY) { |
740 | /* not found - try and create a new one */ | |
d84f4f99 | 741 | keyring = keyring_alloc(name, old->uid, old->gid, old, |
7e047ef5 | 742 | KEY_ALLOC_IN_QUOTA, NULL); |
1da177e4 LT |
743 | if (IS_ERR(keyring)) { |
744 | ret = PTR_ERR(keyring); | |
bcf945d3 | 745 | goto error2; |
1da177e4 | 746 | } |
d84f4f99 | 747 | } else if (IS_ERR(keyring)) { |
1da177e4 LT |
748 | ret = PTR_ERR(keyring); |
749 | goto error2; | |
750 | } | |
751 | ||
752 | /* we've got a keyring - now to install it */ | |
d84f4f99 | 753 | ret = install_session_keyring_to_cred(new, keyring); |
1da177e4 LT |
754 | if (ret < 0) |
755 | goto error2; | |
756 | ||
d84f4f99 DH |
757 | commit_creds(new); |
758 | mutex_unlock(&key_session_mutex); | |
759 | ||
1da177e4 LT |
760 | ret = keyring->serial; |
761 | key_put(keyring); | |
d84f4f99 DH |
762 | okay: |
763 | return ret; | |
1da177e4 | 764 | |
664cceb0 | 765 | error2: |
bb003079 | 766 | mutex_unlock(&key_session_mutex); |
664cceb0 | 767 | error: |
d84f4f99 | 768 | abort_creds(new); |
1da177e4 | 769 | return ret; |
d84f4f99 | 770 | } |
ee18d64c DH |
771 | |
772 | /* | |
773 | * Replace a process's session keyring when that process resumes userspace on | |
774 | * behalf of one of its children | |
775 | */ | |
776 | void key_replace_session_keyring(void) | |
777 | { | |
778 | const struct cred *old; | |
779 | struct cred *new; | |
780 | ||
781 | if (!current->replacement_session_keyring) | |
782 | return; | |
783 | ||
784 | write_lock_irq(&tasklist_lock); | |
785 | new = current->replacement_session_keyring; | |
786 | current->replacement_session_keyring = NULL; | |
787 | write_unlock_irq(&tasklist_lock); | |
788 | ||
789 | if (!new) | |
790 | return; | |
791 | ||
792 | old = current_cred(); | |
793 | new-> uid = old-> uid; | |
794 | new-> euid = old-> euid; | |
795 | new-> suid = old-> suid; | |
796 | new->fsuid = old->fsuid; | |
797 | new-> gid = old-> gid; | |
798 | new-> egid = old-> egid; | |
799 | new-> sgid = old-> sgid; | |
800 | new->fsgid = old->fsgid; | |
801 | new->user = get_uid(old->user); | |
802 | new->group_info = get_group_info(old->group_info); | |
803 | ||
804 | new->securebits = old->securebits; | |
805 | new->cap_inheritable = old->cap_inheritable; | |
806 | new->cap_permitted = old->cap_permitted; | |
807 | new->cap_effective = old->cap_effective; | |
808 | new->cap_bset = old->cap_bset; | |
809 | ||
810 | new->jit_keyring = old->jit_keyring; | |
811 | new->thread_keyring = key_get(old->thread_keyring); | |
812 | new->tgcred->tgid = old->tgcred->tgid; | |
813 | new->tgcred->process_keyring = key_get(old->tgcred->process_keyring); | |
814 | ||
815 | security_transfer_creds(new, old); | |
816 | ||
817 | commit_creds(new); | |
818 | } |