Commit | Line | Data |
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1da177e4 LT |
1 | /* process_keys.c: management of a process's keyrings |
2 | * | |
8589b4e0 | 3 | * Copyright (C) 2004-5 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> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/keyctl.h> | |
17 | #include <linux/fs.h> | |
18 | #include <linux/err.h> | |
19 | #include <asm/uaccess.h> | |
20 | #include "internal.h" | |
21 | ||
22 | /* session keyring create vs join semaphore */ | |
23 | static DECLARE_MUTEX(key_session_sem); | |
24 | ||
25 | /* the root user's tracking struct */ | |
26 | struct key_user root_key_user = { | |
27 | .usage = ATOMIC_INIT(3), | |
28 | .consq = LIST_HEAD_INIT(root_key_user.consq), | |
29 | .lock = SPIN_LOCK_UNLOCKED, | |
30 | .nkeys = ATOMIC_INIT(2), | |
31 | .nikeys = ATOMIC_INIT(2), | |
32 | .uid = 0, | |
33 | }; | |
34 | ||
35 | /* the root user's UID keyring */ | |
36 | struct key root_user_keyring = { | |
37 | .usage = ATOMIC_INIT(1), | |
38 | .serial = 2, | |
39 | .type = &key_type_keyring, | |
40 | .user = &root_key_user, | |
1da177e4 | 41 | .sem = __RWSEM_INITIALIZER(root_user_keyring.sem), |
29db9190 | 42 | .perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL, |
76d8aeab | 43 | .flags = 1 << KEY_FLAG_INSTANTIATED, |
1da177e4 LT |
44 | .description = "_uid.0", |
45 | #ifdef KEY_DEBUGGING | |
46 | .magic = KEY_DEBUG_MAGIC, | |
47 | #endif | |
48 | }; | |
49 | ||
50 | /* the root user's default session keyring */ | |
51 | struct key root_session_keyring = { | |
52 | .usage = ATOMIC_INIT(1), | |
53 | .serial = 1, | |
54 | .type = &key_type_keyring, | |
55 | .user = &root_key_user, | |
1da177e4 | 56 | .sem = __RWSEM_INITIALIZER(root_session_keyring.sem), |
29db9190 | 57 | .perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL, |
76d8aeab | 58 | .flags = 1 << KEY_FLAG_INSTANTIATED, |
1da177e4 LT |
59 | .description = "_uid_ses.0", |
60 | #ifdef KEY_DEBUGGING | |
61 | .magic = KEY_DEBUG_MAGIC, | |
62 | #endif | |
63 | }; | |
64 | ||
65 | /*****************************************************************************/ | |
66 | /* | |
67 | * allocate the keyrings to be associated with a UID | |
68 | */ | |
69 | int alloc_uid_keyring(struct user_struct *user) | |
70 | { | |
71 | struct key *uid_keyring, *session_keyring; | |
72 | char buf[20]; | |
73 | int ret; | |
74 | ||
75 | /* concoct a default session keyring */ | |
76 | sprintf(buf, "_uid_ses.%u", user->uid); | |
77 | ||
78 | session_keyring = keyring_alloc(buf, user->uid, (gid_t) -1, 0, NULL); | |
79 | if (IS_ERR(session_keyring)) { | |
80 | ret = PTR_ERR(session_keyring); | |
81 | goto error; | |
82 | } | |
83 | ||
84 | /* and a UID specific keyring, pointed to by the default session | |
85 | * keyring */ | |
86 | sprintf(buf, "_uid.%u", user->uid); | |
87 | ||
88 | uid_keyring = keyring_alloc(buf, user->uid, (gid_t) -1, 0, | |
89 | session_keyring); | |
90 | if (IS_ERR(uid_keyring)) { | |
91 | key_put(session_keyring); | |
92 | ret = PTR_ERR(uid_keyring); | |
93 | goto error; | |
94 | } | |
95 | ||
96 | /* install the keyrings */ | |
97 | user->uid_keyring = uid_keyring; | |
98 | user->session_keyring = session_keyring; | |
99 | ret = 0; | |
100 | ||
664cceb0 | 101 | error: |
1da177e4 LT |
102 | return ret; |
103 | ||
104 | } /* end alloc_uid_keyring() */ | |
105 | ||
106 | /*****************************************************************************/ | |
107 | /* | |
108 | * deal with the UID changing | |
109 | */ | |
110 | void switch_uid_keyring(struct user_struct *new_user) | |
111 | { | |
112 | #if 0 /* do nothing for now */ | |
113 | struct key *old; | |
114 | ||
115 | /* switch to the new user's session keyring if we were running under | |
116 | * root's default session keyring */ | |
117 | if (new_user->uid != 0 && | |
118 | current->session_keyring == &root_session_keyring | |
119 | ) { | |
120 | atomic_inc(&new_user->session_keyring->usage); | |
121 | ||
122 | task_lock(current); | |
123 | old = current->session_keyring; | |
124 | current->session_keyring = new_user->session_keyring; | |
125 | task_unlock(current); | |
126 | ||
127 | key_put(old); | |
128 | } | |
129 | #endif | |
130 | ||
131 | } /* end switch_uid_keyring() */ | |
132 | ||
133 | /*****************************************************************************/ | |
134 | /* | |
135 | * install a fresh thread keyring, discarding the old one | |
136 | */ | |
137 | int install_thread_keyring(struct task_struct *tsk) | |
138 | { | |
139 | struct key *keyring, *old; | |
140 | char buf[20]; | |
141 | int ret; | |
142 | ||
143 | sprintf(buf, "_tid.%u", tsk->pid); | |
144 | ||
145 | keyring = keyring_alloc(buf, tsk->uid, tsk->gid, 1, NULL); | |
146 | if (IS_ERR(keyring)) { | |
147 | ret = PTR_ERR(keyring); | |
148 | goto error; | |
149 | } | |
150 | ||
151 | task_lock(tsk); | |
152 | old = tsk->thread_keyring; | |
153 | tsk->thread_keyring = keyring; | |
154 | task_unlock(tsk); | |
155 | ||
156 | ret = 0; | |
157 | ||
158 | key_put(old); | |
664cceb0 | 159 | error: |
1da177e4 LT |
160 | return ret; |
161 | ||
162 | } /* end install_thread_keyring() */ | |
163 | ||
164 | /*****************************************************************************/ | |
165 | /* | |
166 | * make sure a process keyring is installed | |
167 | */ | |
3e30148c | 168 | int install_process_keyring(struct task_struct *tsk) |
1da177e4 LT |
169 | { |
170 | unsigned long flags; | |
171 | struct key *keyring; | |
172 | char buf[20]; | |
173 | int ret; | |
174 | ||
175 | if (!tsk->signal->process_keyring) { | |
176 | sprintf(buf, "_pid.%u", tsk->tgid); | |
177 | ||
178 | keyring = keyring_alloc(buf, tsk->uid, tsk->gid, 1, NULL); | |
179 | if (IS_ERR(keyring)) { | |
180 | ret = PTR_ERR(keyring); | |
181 | goto error; | |
182 | } | |
183 | ||
8589b4e0 | 184 | /* attach keyring */ |
1da177e4 LT |
185 | spin_lock_irqsave(&tsk->sighand->siglock, flags); |
186 | if (!tsk->signal->process_keyring) { | |
187 | tsk->signal->process_keyring = keyring; | |
188 | keyring = NULL; | |
189 | } | |
190 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); | |
191 | ||
192 | key_put(keyring); | |
193 | } | |
194 | ||
195 | ret = 0; | |
664cceb0 | 196 | error: |
1da177e4 LT |
197 | return ret; |
198 | ||
199 | } /* end install_process_keyring() */ | |
200 | ||
201 | /*****************************************************************************/ | |
202 | /* | |
203 | * install a session keyring, discarding the old one | |
204 | * - if a keyring is not supplied, an empty one is invented | |
205 | */ | |
206 | static int install_session_keyring(struct task_struct *tsk, | |
207 | struct key *keyring) | |
208 | { | |
209 | unsigned long flags; | |
210 | struct key *old; | |
211 | char buf[20]; | |
212 | int ret; | |
213 | ||
214 | /* create an empty session keyring */ | |
215 | if (!keyring) { | |
216 | sprintf(buf, "_ses.%u", tsk->tgid); | |
217 | ||
218 | keyring = keyring_alloc(buf, tsk->uid, tsk->gid, 1, NULL); | |
219 | if (IS_ERR(keyring)) { | |
220 | ret = PTR_ERR(keyring); | |
221 | goto error; | |
222 | } | |
223 | } | |
224 | else { | |
225 | atomic_inc(&keyring->usage); | |
226 | } | |
227 | ||
228 | /* install the keyring */ | |
229 | spin_lock_irqsave(&tsk->sighand->siglock, flags); | |
8589b4e0 DH |
230 | old = rcu_dereference(tsk->signal->session_keyring); |
231 | rcu_assign_pointer(tsk->signal->session_keyring, keyring); | |
1da177e4 LT |
232 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); |
233 | ||
234 | ret = 0; | |
235 | ||
8589b4e0 | 236 | /* we're using RCU on the pointer */ |
b2b18660 | 237 | synchronize_rcu(); |
1da177e4 | 238 | key_put(old); |
664cceb0 | 239 | error: |
1da177e4 LT |
240 | return ret; |
241 | ||
242 | } /* end install_session_keyring() */ | |
243 | ||
244 | /*****************************************************************************/ | |
245 | /* | |
246 | * copy the keys in a thread group for fork without CLONE_THREAD | |
247 | */ | |
248 | int copy_thread_group_keys(struct task_struct *tsk) | |
249 | { | |
1da177e4 LT |
250 | key_check(current->thread_group->session_keyring); |
251 | key_check(current->thread_group->process_keyring); | |
252 | ||
253 | /* no process keyring yet */ | |
254 | tsk->signal->process_keyring = NULL; | |
255 | ||
256 | /* same session keyring */ | |
8589b4e0 | 257 | rcu_read_lock(); |
1da177e4 | 258 | tsk->signal->session_keyring = |
8589b4e0 DH |
259 | key_get(rcu_dereference(current->signal->session_keyring)); |
260 | rcu_read_unlock(); | |
1da177e4 LT |
261 | |
262 | return 0; | |
263 | ||
264 | } /* end copy_thread_group_keys() */ | |
265 | ||
266 | /*****************************************************************************/ | |
267 | /* | |
268 | * copy the keys for fork | |
269 | */ | |
270 | int copy_keys(unsigned long clone_flags, struct task_struct *tsk) | |
271 | { | |
272 | key_check(tsk->thread_keyring); | |
273 | ||
274 | /* no thread keyring yet */ | |
275 | tsk->thread_keyring = NULL; | |
276 | return 0; | |
277 | ||
278 | } /* end copy_keys() */ | |
279 | ||
280 | /*****************************************************************************/ | |
281 | /* | |
282 | * dispose of thread group keys upon thread group destruction | |
283 | */ | |
284 | void exit_thread_group_keys(struct signal_struct *tg) | |
285 | { | |
286 | key_put(tg->session_keyring); | |
287 | key_put(tg->process_keyring); | |
288 | ||
289 | } /* end exit_thread_group_keys() */ | |
290 | ||
291 | /*****************************************************************************/ | |
292 | /* | |
293 | * dispose of keys upon thread exit | |
294 | */ | |
295 | void exit_keys(struct task_struct *tsk) | |
296 | { | |
297 | key_put(tsk->thread_keyring); | |
298 | ||
299 | } /* end exit_keys() */ | |
300 | ||
301 | /*****************************************************************************/ | |
302 | /* | |
303 | * deal with execve() | |
304 | */ | |
305 | int exec_keys(struct task_struct *tsk) | |
306 | { | |
307 | unsigned long flags; | |
308 | struct key *old; | |
309 | ||
310 | /* newly exec'd tasks don't get a thread keyring */ | |
311 | task_lock(tsk); | |
312 | old = tsk->thread_keyring; | |
313 | tsk->thread_keyring = NULL; | |
314 | task_unlock(tsk); | |
315 | ||
316 | key_put(old); | |
317 | ||
318 | /* discard the process keyring from a newly exec'd task */ | |
319 | spin_lock_irqsave(&tsk->sighand->siglock, flags); | |
320 | old = tsk->signal->process_keyring; | |
321 | tsk->signal->process_keyring = NULL; | |
322 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); | |
323 | ||
324 | key_put(old); | |
325 | ||
326 | return 0; | |
327 | ||
328 | } /* end exec_keys() */ | |
329 | ||
330 | /*****************************************************************************/ | |
331 | /* | |
332 | * deal with SUID programs | |
333 | * - we might want to make this invent a new session keyring | |
334 | */ | |
335 | int suid_keys(struct task_struct *tsk) | |
336 | { | |
337 | return 0; | |
338 | ||
339 | } /* end suid_keys() */ | |
340 | ||
341 | /*****************************************************************************/ | |
342 | /* | |
343 | * the filesystem user ID changed | |
344 | */ | |
345 | void key_fsuid_changed(struct task_struct *tsk) | |
346 | { | |
347 | /* update the ownership of the thread keyring */ | |
348 | if (tsk->thread_keyring) { | |
349 | down_write(&tsk->thread_keyring->sem); | |
1da177e4 | 350 | tsk->thread_keyring->uid = tsk->fsuid; |
1da177e4 LT |
351 | up_write(&tsk->thread_keyring->sem); |
352 | } | |
353 | ||
354 | } /* end key_fsuid_changed() */ | |
355 | ||
356 | /*****************************************************************************/ | |
357 | /* | |
358 | * the filesystem group ID changed | |
359 | */ | |
360 | void key_fsgid_changed(struct task_struct *tsk) | |
361 | { | |
362 | /* update the ownership of the thread keyring */ | |
363 | if (tsk->thread_keyring) { | |
364 | down_write(&tsk->thread_keyring->sem); | |
1da177e4 | 365 | tsk->thread_keyring->gid = tsk->fsgid; |
1da177e4 LT |
366 | up_write(&tsk->thread_keyring->sem); |
367 | } | |
368 | ||
369 | } /* end key_fsgid_changed() */ | |
370 | ||
371 | /*****************************************************************************/ | |
372 | /* | |
373 | * search the process keyrings for the first matching key | |
374 | * - we use the supplied match function to see if the description (or other | |
375 | * feature of interest) matches | |
376 | * - we return -EAGAIN if we didn't find any matching key | |
377 | * - we return -ENOKEY if we found only negative matching keys | |
378 | */ | |
664cceb0 DH |
379 | key_ref_t search_process_keyrings(struct key_type *type, |
380 | const void *description, | |
381 | key_match_func_t match, | |
382 | struct task_struct *context) | |
1da177e4 | 383 | { |
3e30148c | 384 | struct request_key_auth *rka; |
664cceb0 | 385 | key_ref_t key_ref, ret, err, instkey_ref; |
1da177e4 LT |
386 | |
387 | /* we want to return -EAGAIN or -ENOKEY if any of the keyrings were | |
388 | * searchable, but we failed to find a key or we found a negative key; | |
389 | * otherwise we want to return a sample error (probably -EACCES) if | |
390 | * none of the keyrings were searchable | |
391 | * | |
392 | * in terms of priority: success > -ENOKEY > -EAGAIN > other error | |
393 | */ | |
664cceb0 | 394 | key_ref = NULL; |
1da177e4 LT |
395 | ret = NULL; |
396 | err = ERR_PTR(-EAGAIN); | |
397 | ||
398 | /* search the thread keyring first */ | |
3e30148c | 399 | if (context->thread_keyring) { |
664cceb0 DH |
400 | key_ref = keyring_search_aux( |
401 | make_key_ref(context->thread_keyring, 1), | |
402 | context, type, description, match); | |
403 | if (!IS_ERR(key_ref)) | |
1da177e4 LT |
404 | goto found; |
405 | ||
664cceb0 | 406 | switch (PTR_ERR(key_ref)) { |
1da177e4 LT |
407 | case -EAGAIN: /* no key */ |
408 | if (ret) | |
409 | break; | |
410 | case -ENOKEY: /* negative key */ | |
664cceb0 | 411 | ret = key_ref; |
1da177e4 LT |
412 | break; |
413 | default: | |
664cceb0 | 414 | err = key_ref; |
1da177e4 LT |
415 | break; |
416 | } | |
417 | } | |
418 | ||
419 | /* search the process keyring second */ | |
3e30148c | 420 | if (context->signal->process_keyring) { |
664cceb0 DH |
421 | key_ref = keyring_search_aux( |
422 | make_key_ref(context->signal->process_keyring, 1), | |
423 | context, type, description, match); | |
424 | if (!IS_ERR(key_ref)) | |
1da177e4 LT |
425 | goto found; |
426 | ||
664cceb0 | 427 | switch (PTR_ERR(key_ref)) { |
1da177e4 LT |
428 | case -EAGAIN: /* no key */ |
429 | if (ret) | |
430 | break; | |
431 | case -ENOKEY: /* negative key */ | |
664cceb0 | 432 | ret = key_ref; |
1da177e4 LT |
433 | break; |
434 | default: | |
664cceb0 | 435 | err = key_ref; |
1da177e4 LT |
436 | break; |
437 | } | |
438 | } | |
439 | ||
3e30148c DH |
440 | /* search the session keyring */ |
441 | if (context->signal->session_keyring) { | |
8589b4e0 | 442 | rcu_read_lock(); |
664cceb0 DH |
443 | key_ref = keyring_search_aux( |
444 | make_key_ref(rcu_dereference( | |
445 | context->signal->session_keyring), | |
446 | 1), | |
3e30148c | 447 | context, type, description, match); |
8589b4e0 | 448 | rcu_read_unlock(); |
3e30148c | 449 | |
664cceb0 | 450 | if (!IS_ERR(key_ref)) |
3e30148c DH |
451 | goto found; |
452 | ||
664cceb0 | 453 | switch (PTR_ERR(key_ref)) { |
3e30148c DH |
454 | case -EAGAIN: /* no key */ |
455 | if (ret) | |
456 | break; | |
457 | case -ENOKEY: /* negative key */ | |
664cceb0 | 458 | ret = key_ref; |
3e30148c DH |
459 | break; |
460 | default: | |
664cceb0 | 461 | err = key_ref; |
3e30148c DH |
462 | break; |
463 | } | |
464 | ||
465 | /* if this process has a session keyring and that has an | |
466 | * instantiation authorisation key in the bottom level, then we | |
467 | * also search the keyrings of the process mentioned there */ | |
468 | if (context != current) | |
469 | goto no_key; | |
470 | ||
471 | rcu_read_lock(); | |
664cceb0 DH |
472 | instkey_ref = __keyring_search_one( |
473 | make_key_ref(rcu_dereference( | |
474 | context->signal->session_keyring), | |
475 | 1), | |
3e30148c DH |
476 | &key_type_request_key_auth, NULL, 0); |
477 | rcu_read_unlock(); | |
478 | ||
664cceb0 | 479 | if (IS_ERR(instkey_ref)) |
3e30148c DH |
480 | goto no_key; |
481 | ||
664cceb0 | 482 | rka = key_ref_to_ptr(instkey_ref)->payload.data; |
3e30148c | 483 | |
664cceb0 DH |
484 | key_ref = search_process_keyrings(type, description, match, |
485 | rka->context); | |
486 | key_ref_put(instkey_ref); | |
3e30148c | 487 | |
664cceb0 | 488 | if (!IS_ERR(key_ref)) |
3e30148c DH |
489 | goto found; |
490 | ||
664cceb0 | 491 | switch (PTR_ERR(key_ref)) { |
3e30148c DH |
492 | case -EAGAIN: /* no key */ |
493 | if (ret) | |
494 | break; | |
495 | case -ENOKEY: /* negative key */ | |
664cceb0 | 496 | ret = key_ref; |
3e30148c DH |
497 | break; |
498 | default: | |
664cceb0 | 499 | err = key_ref; |
3e30148c DH |
500 | break; |
501 | } | |
8589b4e0 | 502 | } |
3e30148c | 503 | /* or search the user-session keyring */ |
8589b4e0 | 504 | else { |
664cceb0 DH |
505 | key_ref = keyring_search_aux( |
506 | make_key_ref(context->user->session_keyring, 1), | |
507 | context, type, description, match); | |
508 | if (!IS_ERR(key_ref)) | |
3e30148c | 509 | goto found; |
1da177e4 | 510 | |
664cceb0 | 511 | switch (PTR_ERR(key_ref)) { |
3e30148c DH |
512 | case -EAGAIN: /* no key */ |
513 | if (ret) | |
514 | break; | |
515 | case -ENOKEY: /* negative key */ | |
664cceb0 | 516 | ret = key_ref; |
1da177e4 | 517 | break; |
3e30148c | 518 | default: |
664cceb0 | 519 | err = key_ref; |
3e30148c DH |
520 | break; |
521 | } | |
1da177e4 LT |
522 | } |
523 | ||
3e30148c DH |
524 | |
525 | no_key: | |
1da177e4 | 526 | /* no key - decide on the error we're going to go for */ |
664cceb0 | 527 | key_ref = ret ? ret : err; |
1da177e4 | 528 | |
3e30148c | 529 | found: |
664cceb0 | 530 | return key_ref; |
1da177e4 | 531 | |
1da177e4 LT |
532 | } /* end search_process_keyrings() */ |
533 | ||
664cceb0 DH |
534 | /*****************************************************************************/ |
535 | /* | |
536 | * see if the key we're looking at is the target key | |
537 | */ | |
538 | static int lookup_user_key_possessed(const struct key *key, const void *target) | |
539 | { | |
540 | return key == target; | |
541 | ||
542 | } /* end lookup_user_key_possessed() */ | |
543 | ||
1da177e4 LT |
544 | /*****************************************************************************/ |
545 | /* | |
546 | * lookup a key given a key ID from userspace with a given permissions mask | |
547 | * - don't create special keyrings unless so requested | |
548 | * - partially constructed keys aren't found unless requested | |
549 | */ | |
664cceb0 DH |
550 | key_ref_t lookup_user_key(struct task_struct *context, key_serial_t id, |
551 | int create, int partial, key_perm_t perm) | |
1da177e4 | 552 | { |
664cceb0 | 553 | key_ref_t key_ref, skey_ref; |
1da177e4 LT |
554 | struct key *key; |
555 | int ret; | |
556 | ||
3e30148c DH |
557 | if (!context) |
558 | context = current; | |
559 | ||
664cceb0 | 560 | key_ref = ERR_PTR(-ENOKEY); |
1da177e4 LT |
561 | |
562 | switch (id) { | |
563 | case KEY_SPEC_THREAD_KEYRING: | |
3e30148c | 564 | if (!context->thread_keyring) { |
1da177e4 LT |
565 | if (!create) |
566 | goto error; | |
567 | ||
3e30148c | 568 | ret = install_thread_keyring(context); |
1da177e4 LT |
569 | if (ret < 0) { |
570 | key = ERR_PTR(ret); | |
571 | goto error; | |
572 | } | |
573 | } | |
574 | ||
3e30148c | 575 | key = context->thread_keyring; |
1da177e4 | 576 | atomic_inc(&key->usage); |
664cceb0 | 577 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
578 | break; |
579 | ||
580 | case KEY_SPEC_PROCESS_KEYRING: | |
3e30148c | 581 | if (!context->signal->process_keyring) { |
1da177e4 LT |
582 | if (!create) |
583 | goto error; | |
584 | ||
3e30148c | 585 | ret = install_process_keyring(context); |
1da177e4 LT |
586 | if (ret < 0) { |
587 | key = ERR_PTR(ret); | |
588 | goto error; | |
589 | } | |
590 | } | |
591 | ||
3e30148c | 592 | key = context->signal->process_keyring; |
1da177e4 | 593 | atomic_inc(&key->usage); |
664cceb0 | 594 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
595 | break; |
596 | ||
597 | case KEY_SPEC_SESSION_KEYRING: | |
3e30148c | 598 | if (!context->signal->session_keyring) { |
1da177e4 LT |
599 | /* always install a session keyring upon access if one |
600 | * doesn't exist yet */ | |
601 | ret = install_session_keyring( | |
664cceb0 | 602 | context, context->user->session_keyring); |
1da177e4 LT |
603 | if (ret < 0) |
604 | goto error; | |
605 | } | |
606 | ||
3e30148c DH |
607 | rcu_read_lock(); |
608 | key = rcu_dereference(context->signal->session_keyring); | |
1da177e4 | 609 | atomic_inc(&key->usage); |
3e30148c | 610 | rcu_read_unlock(); |
664cceb0 | 611 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
612 | break; |
613 | ||
614 | case KEY_SPEC_USER_KEYRING: | |
3e30148c | 615 | key = context->user->uid_keyring; |
1da177e4 | 616 | atomic_inc(&key->usage); |
664cceb0 | 617 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
618 | break; |
619 | ||
620 | case KEY_SPEC_USER_SESSION_KEYRING: | |
3e30148c | 621 | key = context->user->session_keyring; |
1da177e4 | 622 | atomic_inc(&key->usage); |
664cceb0 | 623 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
624 | break; |
625 | ||
626 | case KEY_SPEC_GROUP_KEYRING: | |
627 | /* group keyrings are not yet supported */ | |
628 | key = ERR_PTR(-EINVAL); | |
629 | goto error; | |
630 | ||
631 | default: | |
664cceb0 | 632 | key_ref = ERR_PTR(-EINVAL); |
1da177e4 LT |
633 | if (id < 1) |
634 | goto error; | |
635 | ||
636 | key = key_lookup(id); | |
664cceb0 DH |
637 | if (IS_ERR(key)) { |
638 | key_ref = ERR_PTR(PTR_ERR(key)); | |
1da177e4 | 639 | goto error; |
664cceb0 DH |
640 | } |
641 | ||
642 | key_ref = make_key_ref(key, 0); | |
643 | ||
644 | /* check to see if we possess the key */ | |
645 | skey_ref = search_process_keyrings(key->type, key, | |
646 | lookup_user_key_possessed, | |
647 | current); | |
648 | ||
649 | if (!IS_ERR(skey_ref)) { | |
650 | key_put(key); | |
651 | key_ref = skey_ref; | |
652 | } | |
653 | ||
1da177e4 LT |
654 | break; |
655 | } | |
656 | ||
3e30148c | 657 | /* check the status */ |
1da177e4 LT |
658 | if (perm) { |
659 | ret = key_validate(key); | |
660 | if (ret < 0) | |
661 | goto invalid_key; | |
662 | } | |
663 | ||
664 | ret = -EIO; | |
76d8aeab | 665 | if (!partial && !test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) |
1da177e4 LT |
666 | goto invalid_key; |
667 | ||
3e30148c | 668 | /* check the permissions */ |
29db9190 DH |
669 | ret = key_task_permission(key_ref, context, perm); |
670 | if (ret < 0) | |
1da177e4 LT |
671 | goto invalid_key; |
672 | ||
664cceb0 DH |
673 | error: |
674 | return key_ref; | |
1da177e4 | 675 | |
664cceb0 DH |
676 | invalid_key: |
677 | key_ref_put(key_ref); | |
678 | key_ref = ERR_PTR(ret); | |
1da177e4 LT |
679 | goto error; |
680 | ||
681 | } /* end lookup_user_key() */ | |
682 | ||
683 | /*****************************************************************************/ | |
684 | /* | |
685 | * join the named keyring as the session keyring if possible, or attempt to | |
686 | * create a new one of that name if not | |
687 | * - if the name is NULL, an empty anonymous keyring is installed instead | |
688 | * - named session keyring joining is done with a semaphore held | |
689 | */ | |
690 | long join_session_keyring(const char *name) | |
691 | { | |
692 | struct task_struct *tsk = current; | |
1da177e4 LT |
693 | struct key *keyring; |
694 | long ret; | |
695 | ||
696 | /* if no name is provided, install an anonymous keyring */ | |
697 | if (!name) { | |
698 | ret = install_session_keyring(tsk, NULL); | |
699 | if (ret < 0) | |
700 | goto error; | |
701 | ||
3e30148c DH |
702 | rcu_read_lock(); |
703 | ret = rcu_dereference(tsk->signal->session_keyring)->serial; | |
704 | rcu_read_unlock(); | |
1da177e4 LT |
705 | goto error; |
706 | } | |
707 | ||
708 | /* allow the user to join or create a named keyring */ | |
709 | down(&key_session_sem); | |
710 | ||
711 | /* look for an existing keyring of this name */ | |
712 | keyring = find_keyring_by_name(name, 0); | |
713 | if (PTR_ERR(keyring) == -ENOKEY) { | |
714 | /* not found - try and create a new one */ | |
715 | keyring = keyring_alloc(name, tsk->uid, tsk->gid, 0, NULL); | |
716 | if (IS_ERR(keyring)) { | |
717 | ret = PTR_ERR(keyring); | |
bcf945d3 | 718 | goto error2; |
1da177e4 LT |
719 | } |
720 | } | |
721 | else if (IS_ERR(keyring)) { | |
722 | ret = PTR_ERR(keyring); | |
723 | goto error2; | |
724 | } | |
725 | ||
726 | /* we've got a keyring - now to install it */ | |
727 | ret = install_session_keyring(tsk, keyring); | |
728 | if (ret < 0) | |
729 | goto error2; | |
730 | ||
731 | ret = keyring->serial; | |
732 | key_put(keyring); | |
733 | ||
664cceb0 | 734 | error2: |
1da177e4 | 735 | up(&key_session_sem); |
664cceb0 | 736 | error: |
1da177e4 LT |
737 | return ret; |
738 | ||
739 | } /* end join_session_keyring() */ |