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KEYS: fix keyctl_set_reqkey_keyring() to not leak thread keyrings
[mirror_ubuntu-zesty-kernel.git] / security / keys / process_keys.c
CommitLineData
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>
7c0f6ba6 21#include <linux/uaccess.h>
1da177e4
LT
22#include "internal.h"
23
973c9f4f 24/* Session keyring create vs join semaphore */
bb003079 25static DEFINE_MUTEX(key_session_mutex);
1da177e4 26
973c9f4f 27/* User keyring creation semaphore */
69664cf1
DH
28static DEFINE_MUTEX(key_user_keyring_mutex);
29
973c9f4f 30/* The root user's tracking struct */
1da177e4
LT
31struct 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),
9a56c2db 37 .uid = GLOBAL_ROOT_UID,
1da177e4
LT
38};
39
1da177e4 40/*
973c9f4f 41 * Install the user and user session keyrings for the current process's UID.
1da177e4 42 */
8bbf4976 43int install_user_keyrings(void)
1da177e4 44{
d84f4f99
DH
45 struct user_struct *user;
46 const struct cred *cred;
1da177e4 47 struct key *uid_keyring, *session_keyring;
96b5c8fe 48 key_perm_t user_keyring_perm;
1da177e4
LT
49 char buf[20];
50 int ret;
9a56c2db 51 uid_t uid;
1da177e4 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;
9a56c2db 56 uid = from_kuid(cred->user_ns, user->uid);
d84f4f99 57
9a56c2db 58 kenter("%p{%u}", user, uid);
1da177e4 59
0da9dfdd 60 if (user->uid_keyring && user->session_keyring) {
69664cf1
DH
61 kleave(" = 0 [exist]");
62 return 0;
1da177e4
LT
63 }
64
69664cf1
DH
65 mutex_lock(&key_user_keyring_mutex);
66 ret = 0;
1da177e4 67
69664cf1
DH
68 if (!user->uid_keyring) {
69 /* get the UID-specific keyring
70 * - there may be one in existence already as it may have been
71 * pinned by a session, but the user_struct pointing to it
72 * may have been destroyed by setuid */
9a56c2db 73 sprintf(buf, "_uid.%u", uid);
69664cf1
DH
74
75 uid_keyring = find_keyring_by_name(buf, true);
76 if (IS_ERR(uid_keyring)) {
9a56c2db 77 uid_keyring = keyring_alloc(buf, user->uid, INVALID_GID,
96b5c8fe 78 cred, user_keyring_perm,
5ac7eace
DH
79 KEY_ALLOC_IN_QUOTA,
80 NULL, NULL);
69664cf1
DH
81 if (IS_ERR(uid_keyring)) {
82 ret = PTR_ERR(uid_keyring);
83 goto error;
84 }
85 }
86
87 /* get a default session keyring (which might also exist
88 * already) */
9a56c2db 89 sprintf(buf, "_uid_ses.%u", uid);
69664cf1
DH
90
91 session_keyring = find_keyring_by_name(buf, true);
92 if (IS_ERR(session_keyring)) {
93 session_keyring =
9a56c2db 94 keyring_alloc(buf, user->uid, INVALID_GID,
96b5c8fe 95 cred, user_keyring_perm,
5ac7eace
DH
96 KEY_ALLOC_IN_QUOTA,
97 NULL, NULL);
69664cf1
DH
98 if (IS_ERR(session_keyring)) {
99 ret = PTR_ERR(session_keyring);
100 goto error_release;
101 }
102
103 /* we install a link from the user session keyring to
104 * the user keyring */
105 ret = key_link(session_keyring, uid_keyring);
106 if (ret < 0)
107 goto error_release_both;
108 }
109
110 /* install the keyrings */
111 user->uid_keyring = uid_keyring;
112 user->session_keyring = session_keyring;
1da177e4
LT
113 }
114
69664cf1
DH
115 mutex_unlock(&key_user_keyring_mutex);
116 kleave(" = 0");
117 return 0;
1da177e4 118
69664cf1
DH
119error_release_both:
120 key_put(session_keyring);
121error_release:
122 key_put(uid_keyring);
664cceb0 123error:
69664cf1
DH
124 mutex_unlock(&key_user_keyring_mutex);
125 kleave(" = %d", ret);
1da177e4 126 return ret;
69664cf1 127}
1da177e4 128
1da177e4 129/*
4a09908e
EB
130 * Install a thread keyring to the given credentials struct if it didn't have
131 * one already. This is allowed to overrun the quota.
132 *
133 * Return: 0 if a thread keyring is now present; -errno on failure.
1da177e4 134 */
d84f4f99 135int install_thread_keyring_to_cred(struct cred *new)
1da177e4 136{
d84f4f99 137 struct key *keyring;
1da177e4 138
4a09908e
EB
139 if (new->thread_keyring)
140 return 0;
141
d84f4f99 142 keyring = keyring_alloc("_tid", new->uid, new->gid, new,
96b5c8fe 143 KEY_POS_ALL | KEY_USR_VIEW,
5ac7eace
DH
144 KEY_ALLOC_QUOTA_OVERRUN,
145 NULL, NULL);
d84f4f99
DH
146 if (IS_ERR(keyring))
147 return PTR_ERR(keyring);
1da177e4 148
d84f4f99
DH
149 new->thread_keyring = keyring;
150 return 0;
151}
1da177e4 152
1da177e4 153/*
4a09908e
EB
154 * Install a thread keyring to the current task if it didn't have one already.
155 *
156 * Return: 0 if a thread keyring is now present; -errno on failure.
1da177e4 157 */
d84f4f99 158static int install_thread_keyring(void)
1da177e4 159{
d84f4f99 160 struct cred *new;
1da177e4
LT
161 int ret;
162
d84f4f99
DH
163 new = prepare_creds();
164 if (!new)
165 return -ENOMEM;
1da177e4 166
d84f4f99
DH
167 ret = install_thread_keyring_to_cred(new);
168 if (ret < 0) {
169 abort_creds(new);
170 return ret;
1da177e4
LT
171 }
172
d84f4f99
DH
173 return commit_creds(new);
174}
1da177e4 175
d84f4f99 176/*
4a09908e
EB
177 * Install a process keyring to the given credentials struct if it didn't have
178 * one already. This is allowed to overrun the quota.
973c9f4f 179 *
4a09908e 180 * Return: 0 if a process keyring is now present; -errno on failure.
d84f4f99
DH
181 */
182int install_process_keyring_to_cred(struct cred *new)
183{
184 struct key *keyring;
1da177e4 185
3a50597d 186 if (new->process_keyring)
4a09908e 187 return 0;
d84f4f99 188
96b5c8fe
DH
189 keyring = keyring_alloc("_pid", new->uid, new->gid, new,
190 KEY_POS_ALL | KEY_USR_VIEW,
5ac7eace
DH
191 KEY_ALLOC_QUOTA_OVERRUN,
192 NULL, NULL);
d84f4f99
DH
193 if (IS_ERR(keyring))
194 return PTR_ERR(keyring);
195
3a50597d
DH
196 new->process_keyring = keyring;
197 return 0;
d84f4f99 198}
1da177e4 199
1da177e4 200/*
4a09908e 201 * Install a process keyring to the current task if it didn't have one already.
973c9f4f 202 *
4a09908e 203 * Return: 0 if a process keyring is now present; -errno on failure.
1da177e4 204 */
d84f4f99 205static int install_process_keyring(void)
1da177e4 206{
d84f4f99 207 struct cred *new;
1da177e4
LT
208 int ret;
209
d84f4f99
DH
210 new = prepare_creds();
211 if (!new)
212 return -ENOMEM;
1da177e4 213
d84f4f99
DH
214 ret = install_process_keyring_to_cred(new);
215 if (ret < 0) {
216 abort_creds(new);
4a09908e 217 return ret;
1da177e4
LT
218 }
219
d84f4f99
DH
220 return commit_creds(new);
221}
1da177e4 222
1da177e4 223/*
4a09908e
EB
224 * Install the given keyring as the session keyring of the given credentials
225 * struct, replacing the existing one if any. If the given keyring is NULL,
226 * then install a new anonymous session keyring.
227 *
228 * Return: 0 on success; -errno on failure.
1da177e4 229 */
685bfd2c 230int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
1da177e4 231{
7e047ef5 232 unsigned long flags;
1da177e4 233 struct key *old;
1a26feb9
DH
234
235 might_sleep();
1da177e4
LT
236
237 /* create an empty session keyring */
238 if (!keyring) {
7e047ef5 239 flags = KEY_ALLOC_QUOTA_OVERRUN;
3a50597d 240 if (cred->session_keyring)
7e047ef5
DH
241 flags = KEY_ALLOC_IN_QUOTA;
242
96b5c8fe
DH
243 keyring = keyring_alloc("_ses", cred->uid, cred->gid, cred,
244 KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ,
5ac7eace 245 flags, NULL, NULL);
1a26feb9
DH
246 if (IS_ERR(keyring))
247 return PTR_ERR(keyring);
d84f4f99 248 } else {
ccc3e6d9 249 __key_get(keyring);
1da177e4
LT
250 }
251
252 /* install the keyring */
3a50597d
DH
253 old = cred->session_keyring;
254 rcu_assign_pointer(cred->session_keyring, keyring);
255
256 if (old)
1a26feb9 257 key_put(old);
1da177e4 258
1a26feb9 259 return 0;
d84f4f99 260}
1da177e4 261
1da177e4 262/*
4a09908e
EB
263 * Install the given keyring as the session keyring of the current task,
264 * replacing the existing one if any. If the given keyring is NULL, then
265 * install a new anonymous session keyring.
266 *
267 * Return: 0 on success; -errno on failure.
1da177e4 268 */
d84f4f99 269static int install_session_keyring(struct key *keyring)
1da177e4 270{
d84f4f99
DH
271 struct cred *new;
272 int ret;
1da177e4 273
d84f4f99
DH
274 new = prepare_creds();
275 if (!new)
276 return -ENOMEM;
1da177e4 277
99599537 278 ret = install_session_keyring_to_cred(new, keyring);
d84f4f99
DH
279 if (ret < 0) {
280 abort_creds(new);
281 return ret;
282 }
1da177e4 283
d84f4f99
DH
284 return commit_creds(new);
285}
1da177e4 286
1da177e4 287/*
973c9f4f 288 * Handle the fsuid changing.
1da177e4
LT
289 */
290void key_fsuid_changed(struct task_struct *tsk)
291{
292 /* update the ownership of the thread keyring */
b6dff3ec
DH
293 BUG_ON(!tsk->cred);
294 if (tsk->cred->thread_keyring) {
295 down_write(&tsk->cred->thread_keyring->sem);
296 tsk->cred->thread_keyring->uid = tsk->cred->fsuid;
297 up_write(&tsk->cred->thread_keyring->sem);
1da177e4 298 }
a8b17ed0 299}
1da177e4 300
1da177e4 301/*
973c9f4f 302 * Handle the fsgid changing.
1da177e4
LT
303 */
304void key_fsgid_changed(struct task_struct *tsk)
305{
306 /* update the ownership of the thread keyring */
b6dff3ec
DH
307 BUG_ON(!tsk->cred);
308 if (tsk->cred->thread_keyring) {
309 down_write(&tsk->cred->thread_keyring->sem);
310 tsk->cred->thread_keyring->gid = tsk->cred->fsgid;
311 up_write(&tsk->cred->thread_keyring->sem);
1da177e4 312 }
a8b17ed0 313}
1da177e4 314
1da177e4 315/*
973c9f4f
DH
316 * Search the process keyrings attached to the supplied cred for the first
317 * matching key.
318 *
319 * The search criteria are the type and the match function. The description is
320 * given to the match function as a parameter, but doesn't otherwise influence
321 * the search. Typically the match function will compare the description
322 * parameter to the key's description.
323 *
324 * This can only search keyrings that grant Search permission to the supplied
325 * credentials. Keyrings linked to searched keyrings will also be searched if
326 * they grant Search permission too. Keys can only be found if they grant
327 * Search permission to the credentials.
328 *
329 * Returns a pointer to the key with the key usage count incremented if
330 * successful, -EAGAIN if we didn't find any matching key or -ENOKEY if we only
331 * matched negative keys.
332 *
333 * In the case of a successful return, the possession attribute is set on the
334 * returned key reference.
1da177e4 335 */
4bdf0bc3 336key_ref_t search_my_process_keyrings(struct keyring_search_context *ctx)
1da177e4 337{
b5f545c8 338 key_ref_t key_ref, ret, err;
1da177e4
LT
339
340 /* we want to return -EAGAIN or -ENOKEY if any of the keyrings were
341 * searchable, but we failed to find a key or we found a negative key;
342 * otherwise we want to return a sample error (probably -EACCES) if
343 * none of the keyrings were searchable
344 *
345 * in terms of priority: success > -ENOKEY > -EAGAIN > other error
346 */
664cceb0 347 key_ref = NULL;
1da177e4
LT
348 ret = NULL;
349 err = ERR_PTR(-EAGAIN);
350
351 /* search the thread keyring first */
4bdf0bc3 352 if (ctx->cred->thread_keyring) {
664cceb0 353 key_ref = keyring_search_aux(
4bdf0bc3 354 make_key_ref(ctx->cred->thread_keyring, 1), ctx);
664cceb0 355 if (!IS_ERR(key_ref))
1da177e4
LT
356 goto found;
357
664cceb0 358 switch (PTR_ERR(key_ref)) {
1da177e4 359 case -EAGAIN: /* no key */
1da177e4 360 case -ENOKEY: /* negative key */
664cceb0 361 ret = key_ref;
1da177e4
LT
362 break;
363 default:
664cceb0 364 err = key_ref;
1da177e4
LT
365 break;
366 }
367 }
368
369 /* search the process keyring second */
4bdf0bc3 370 if (ctx->cred->process_keyring) {
664cceb0 371 key_ref = keyring_search_aux(
4bdf0bc3 372 make_key_ref(ctx->cred->process_keyring, 1), ctx);
664cceb0 373 if (!IS_ERR(key_ref))
1da177e4
LT
374 goto found;
375
664cceb0 376 switch (PTR_ERR(key_ref)) {
1da177e4 377 case -EAGAIN: /* no key */
fe9453a1
DH
378 if (ret)
379 break;
1da177e4 380 case -ENOKEY: /* negative key */
664cceb0 381 ret = key_ref;
1da177e4
LT
382 break;
383 default:
664cceb0 384 err = key_ref;
1da177e4
LT
385 break;
386 }
387 }
388
3e30148c 389 /* search the session keyring */
4bdf0bc3 390 if (ctx->cred->session_keyring) {
8589b4e0 391 rcu_read_lock();
664cceb0 392 key_ref = keyring_search_aux(
4bdf0bc3
DH
393 make_key_ref(rcu_dereference(ctx->cred->session_keyring), 1),
394 ctx);
8589b4e0 395 rcu_read_unlock();
3e30148c 396
664cceb0 397 if (!IS_ERR(key_ref))
3e30148c
DH
398 goto found;
399
664cceb0 400 switch (PTR_ERR(key_ref)) {
3e30148c
DH
401 case -EAGAIN: /* no key */
402 if (ret)
403 break;
404 case -ENOKEY: /* negative key */
664cceb0 405 ret = key_ref;
3e30148c
DH
406 break;
407 default:
664cceb0 408 err = key_ref;
3e30148c
DH
409 break;
410 }
b5f545c8
DH
411 }
412 /* or search the user-session keyring */
4bdf0bc3 413 else if (ctx->cred->user->session_keyring) {
b5f545c8 414 key_ref = keyring_search_aux(
4bdf0bc3
DH
415 make_key_ref(ctx->cred->user->session_keyring, 1),
416 ctx);
664cceb0 417 if (!IS_ERR(key_ref))
3e30148c
DH
418 goto found;
419
664cceb0 420 switch (PTR_ERR(key_ref)) {
3e30148c
DH
421 case -EAGAIN: /* no key */
422 if (ret)
423 break;
424 case -ENOKEY: /* negative key */
664cceb0 425 ret = key_ref;
3e30148c
DH
426 break;
427 default:
664cceb0 428 err = key_ref;
3e30148c
DH
429 break;
430 }
8589b4e0 431 }
b5f545c8 432
927942aa
DH
433 /* no key - decide on the error we're going to go for */
434 key_ref = ret ? ret : err;
435
436found:
437 return key_ref;
438}
439
927942aa 440/*
973c9f4f
DH
441 * Search the process keyrings attached to the supplied cred for the first
442 * matching key in the manner of search_my_process_keyrings(), but also search
443 * the keys attached to the assumed authorisation key using its credentials if
444 * one is available.
445 *
446 * Return same as search_my_process_keyrings().
927942aa 447 */
4bdf0bc3 448key_ref_t search_process_keyrings(struct keyring_search_context *ctx)
927942aa
DH
449{
450 struct request_key_auth *rka;
451 key_ref_t key_ref, ret = ERR_PTR(-EACCES), err;
452
453 might_sleep();
454
4bdf0bc3 455 key_ref = search_my_process_keyrings(ctx);
927942aa
DH
456 if (!IS_ERR(key_ref))
457 goto found;
458 err = key_ref;
459
b5f545c8
DH
460 /* if this process has an instantiation authorisation key, then we also
461 * search the keyrings of the process mentioned there
462 * - we don't permit access to request_key auth keys via this method
463 */
4bdf0bc3
DH
464 if (ctx->cred->request_key_auth &&
465 ctx->cred == current_cred() &&
466 ctx->index_key.type != &key_type_request_key_auth
b5f545c8 467 ) {
4bdf0bc3
DH
468 const struct cred *cred = ctx->cred;
469
04c567d9 470 /* defend against the auth key being revoked */
c69e8d9c 471 down_read(&cred->request_key_auth->sem);
b5f545c8 472
4bdf0bc3 473 if (key_validate(ctx->cred->request_key_auth) == 0) {
146aa8b1 474 rka = ctx->cred->request_key_auth->payload.data[0];
b5f545c8 475
4bdf0bc3
DH
476 ctx->cred = rka->cred;
477 key_ref = search_process_keyrings(ctx);
478 ctx->cred = cred;
1da177e4 479
c69e8d9c 480 up_read(&cred->request_key_auth->sem);
04c567d9
DH
481
482 if (!IS_ERR(key_ref))
483 goto found;
484
927942aa 485 ret = key_ref;
04c567d9 486 } else {
c69e8d9c 487 up_read(&cred->request_key_auth->sem);
3e30148c 488 }
1da177e4
LT
489 }
490
491 /* no key - decide on the error we're going to go for */
927942aa
DH
492 if (err == ERR_PTR(-ENOKEY) || ret == ERR_PTR(-ENOKEY))
493 key_ref = ERR_PTR(-ENOKEY);
494 else if (err == ERR_PTR(-EACCES))
495 key_ref = ret;
496 else
497 key_ref = err;
1da177e4 498
3e30148c 499found:
664cceb0 500 return key_ref;
a8b17ed0 501}
1da177e4 502
664cceb0 503/*
973c9f4f 504 * See if the key we're looking at is the target key.
664cceb0 505 */
0c903ab6
DH
506bool lookup_user_key_possessed(const struct key *key,
507 const struct key_match_data *match_data)
664cceb0 508{
46291959 509 return key == match_data->raw_data;
a8b17ed0 510}
664cceb0 511
1da177e4 512/*
973c9f4f
DH
513 * Look up a key ID given us by userspace with a given permissions mask to get
514 * the key it refers to.
515 *
516 * Flags can be passed to request that special keyrings be created if referred
517 * to directly, to permit partially constructed keys to be found and to skip
518 * validity and permission checks on the found key.
519 *
520 * Returns a pointer to the key with an incremented usage count if successful;
521 * -EINVAL if the key ID is invalid; -ENOKEY if the key ID does not correspond
522 * to a key or the best found key was a negative key; -EKEYREVOKED or
523 * -EKEYEXPIRED if the best found key was revoked or expired; -EACCES if the
524 * found key doesn't grant the requested permit or the LSM denied access to it;
525 * or -ENOMEM if a special keyring couldn't be created.
526 *
527 * In the case of a successful return, the possession attribute is set on the
528 * returned key reference.
1da177e4 529 */
5593122e 530key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
8bbf4976 531 key_perm_t perm)
1da177e4 532{
4bdf0bc3 533 struct keyring_search_context ctx = {
46291959
DH
534 .match_data.cmp = lookup_user_key_possessed,
535 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
536 .flags = KEYRING_SEARCH_NO_STATE_CHECK,
4bdf0bc3 537 };
8bbf4976 538 struct request_key_auth *rka;
1da177e4 539 struct key *key;
b6dff3ec 540 key_ref_t key_ref, skey_ref;
1da177e4
LT
541 int ret;
542
bb952bb9 543try_again:
4bdf0bc3 544 ctx.cred = get_current_cred();
664cceb0 545 key_ref = ERR_PTR(-ENOKEY);
1da177e4
LT
546
547 switch (id) {
548 case KEY_SPEC_THREAD_KEYRING:
4bdf0bc3 549 if (!ctx.cred->thread_keyring) {
5593122e 550 if (!(lflags & KEY_LOOKUP_CREATE))
1da177e4
LT
551 goto error;
552
8bbf4976 553 ret = install_thread_keyring();
1da177e4 554 if (ret < 0) {
4d09ec0f 555 key_ref = ERR_PTR(ret);
1da177e4
LT
556 goto error;
557 }
bb952bb9 558 goto reget_creds;
1da177e4
LT
559 }
560
4bdf0bc3 561 key = ctx.cred->thread_keyring;
ccc3e6d9 562 __key_get(key);
664cceb0 563 key_ref = make_key_ref(key, 1);
1da177e4
LT
564 break;
565
566 case KEY_SPEC_PROCESS_KEYRING:
4bdf0bc3 567 if (!ctx.cred->process_keyring) {
5593122e 568 if (!(lflags & KEY_LOOKUP_CREATE))
1da177e4
LT
569 goto error;
570
8bbf4976 571 ret = install_process_keyring();
1da177e4 572 if (ret < 0) {
4d09ec0f 573 key_ref = ERR_PTR(ret);
1da177e4
LT
574 goto error;
575 }
bb952bb9 576 goto reget_creds;
1da177e4
LT
577 }
578
4bdf0bc3 579 key = ctx.cred->process_keyring;
ccc3e6d9 580 __key_get(key);
664cceb0 581 key_ref = make_key_ref(key, 1);
1da177e4
LT
582 break;
583
584 case KEY_SPEC_SESSION_KEYRING:
4bdf0bc3 585 if (!ctx.cred->session_keyring) {
1da177e4
LT
586 /* always install a session keyring upon access if one
587 * doesn't exist yet */
8bbf4976 588 ret = install_user_keyrings();
69664cf1
DH
589 if (ret < 0)
590 goto error;
3ecf1b4f
DH
591 if (lflags & KEY_LOOKUP_CREATE)
592 ret = join_session_keyring(NULL);
593 else
594 ret = install_session_keyring(
4bdf0bc3 595 ctx.cred->user->session_keyring);
d84f4f99 596
1da177e4
LT
597 if (ret < 0)
598 goto error;
bb952bb9 599 goto reget_creds;
4bdf0bc3
DH
600 } else if (ctx.cred->session_keyring ==
601 ctx.cred->user->session_keyring &&
3ecf1b4f
DH
602 lflags & KEY_LOOKUP_CREATE) {
603 ret = join_session_keyring(NULL);
604 if (ret < 0)
605 goto error;
606 goto reget_creds;
1da177e4
LT
607 }
608
3e30148c 609 rcu_read_lock();
4bdf0bc3 610 key = rcu_dereference(ctx.cred->session_keyring);
ccc3e6d9 611 __key_get(key);
3e30148c 612 rcu_read_unlock();
664cceb0 613 key_ref = make_key_ref(key, 1);
1da177e4
LT
614 break;
615
616 case KEY_SPEC_USER_KEYRING:
4bdf0bc3 617 if (!ctx.cred->user->uid_keyring) {
8bbf4976 618 ret = install_user_keyrings();
69664cf1
DH
619 if (ret < 0)
620 goto error;
621 }
622
4bdf0bc3 623 key = ctx.cred->user->uid_keyring;
ccc3e6d9 624 __key_get(key);
664cceb0 625 key_ref = make_key_ref(key, 1);
1da177e4
LT
626 break;
627
628 case KEY_SPEC_USER_SESSION_KEYRING:
4bdf0bc3 629 if (!ctx.cred->user->session_keyring) {
8bbf4976 630 ret = install_user_keyrings();
69664cf1
DH
631 if (ret < 0)
632 goto error;
633 }
634
4bdf0bc3 635 key = ctx.cred->user->session_keyring;
ccc3e6d9 636 __key_get(key);
664cceb0 637 key_ref = make_key_ref(key, 1);
1da177e4
LT
638 break;
639
640 case KEY_SPEC_GROUP_KEYRING:
641 /* group keyrings are not yet supported */
4d09ec0f 642 key_ref = ERR_PTR(-EINVAL);
1da177e4
LT
643 goto error;
644
b5f545c8 645 case KEY_SPEC_REQKEY_AUTH_KEY:
4bdf0bc3 646 key = ctx.cred->request_key_auth;
b5f545c8
DH
647 if (!key)
648 goto error;
649
ccc3e6d9 650 __key_get(key);
b5f545c8
DH
651 key_ref = make_key_ref(key, 1);
652 break;
653
8bbf4976 654 case KEY_SPEC_REQUESTOR_KEYRING:
4bdf0bc3 655 if (!ctx.cred->request_key_auth)
8bbf4976
DH
656 goto error;
657
4bdf0bc3 658 down_read(&ctx.cred->request_key_auth->sem);
f67dabbd 659 if (test_bit(KEY_FLAG_REVOKED,
4bdf0bc3 660 &ctx.cred->request_key_auth->flags)) {
8bbf4976
DH
661 key_ref = ERR_PTR(-EKEYREVOKED);
662 key = NULL;
663 } else {
146aa8b1 664 rka = ctx.cred->request_key_auth->payload.data[0];
8bbf4976 665 key = rka->dest_keyring;
ccc3e6d9 666 __key_get(key);
8bbf4976 667 }
4bdf0bc3 668 up_read(&ctx.cred->request_key_auth->sem);
8bbf4976
DH
669 if (!key)
670 goto error;
671 key_ref = make_key_ref(key, 1);
672 break;
673
1da177e4 674 default:
664cceb0 675 key_ref = ERR_PTR(-EINVAL);
1da177e4
LT
676 if (id < 1)
677 goto error;
678
679 key = key_lookup(id);
664cceb0 680 if (IS_ERR(key)) {
e231c2ee 681 key_ref = ERR_CAST(key);
1da177e4 682 goto error;
664cceb0
DH
683 }
684
685 key_ref = make_key_ref(key, 0);
686
687 /* check to see if we possess the key */
4bdf0bc3
DH
688 ctx.index_key.type = key->type;
689 ctx.index_key.description = key->description;
690 ctx.index_key.desc_len = strlen(key->description);
46291959 691 ctx.match_data.raw_data = key;
4bdf0bc3
DH
692 kdebug("check possessed");
693 skey_ref = search_process_keyrings(&ctx);
694 kdebug("possessed=%p", skey_ref);
664cceb0
DH
695
696 if (!IS_ERR(skey_ref)) {
697 key_put(key);
698 key_ref = skey_ref;
699 }
700
1da177e4
LT
701 break;
702 }
703
5593122e
DH
704 /* unlink does not use the nominated key in any way, so can skip all
705 * the permission checks as it is only concerned with the keyring */
706 if (lflags & KEY_LOOKUP_FOR_UNLINK) {
707 ret = 0;
708 goto error;
709 }
710
711 if (!(lflags & KEY_LOOKUP_PARTIAL)) {
76181c13
DH
712 ret = wait_for_key_construction(key, true);
713 switch (ret) {
714 case -ERESTARTSYS:
715 goto invalid_key;
716 default:
717 if (perm)
718 goto invalid_key;
719 case 0:
720 break;
721 }
722 } else if (perm) {
1da177e4
LT
723 ret = key_validate(key);
724 if (ret < 0)
725 goto invalid_key;
726 }
727
728 ret = -EIO;
5593122e
DH
729 if (!(lflags & KEY_LOOKUP_PARTIAL) &&
730 !test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
1da177e4
LT
731 goto invalid_key;
732
3e30148c 733 /* check the permissions */
4bdf0bc3 734 ret = key_task_permission(key_ref, ctx.cred, perm);
29db9190 735 if (ret < 0)
1da177e4
LT
736 goto invalid_key;
737
31d5a79d
DH
738 key->last_used_at = current_kernel_time().tv_sec;
739
664cceb0 740error:
4bdf0bc3 741 put_cred(ctx.cred);
664cceb0 742 return key_ref;
1da177e4 743
664cceb0
DH
744invalid_key:
745 key_ref_put(key_ref);
746 key_ref = ERR_PTR(ret);
1da177e4
LT
747 goto error;
748
bb952bb9
DH
749 /* if we attempted to install a keyring, then it may have caused new
750 * creds to be installed */
751reget_creds:
4bdf0bc3 752 put_cred(ctx.cred);
bb952bb9 753 goto try_again;
a8b17ed0 754}
bb952bb9 755
1da177e4 756/*
973c9f4f
DH
757 * Join the named keyring as the session keyring if possible else attempt to
758 * create a new one of that name and join that.
759 *
760 * If the name is NULL, an empty anonymous keyring will be installed as the
761 * session keyring.
762 *
763 * Named session keyrings are joined with a semaphore held to prevent the
764 * keyrings from going away whilst the attempt is made to going them and also
765 * to prevent a race in creating compatible session keyrings.
1da177e4
LT
766 */
767long join_session_keyring(const char *name)
768{
d84f4f99
DH
769 const struct cred *old;
770 struct cred *new;
1da177e4 771 struct key *keyring;
d84f4f99
DH
772 long ret, serial;
773
d84f4f99
DH
774 new = prepare_creds();
775 if (!new)
776 return -ENOMEM;
777 old = current_cred();
1da177e4
LT
778
779 /* if no name is provided, install an anonymous keyring */
780 if (!name) {
d84f4f99 781 ret = install_session_keyring_to_cred(new, NULL);
1da177e4
LT
782 if (ret < 0)
783 goto error;
784
3a50597d 785 serial = new->session_keyring->serial;
d84f4f99
DH
786 ret = commit_creds(new);
787 if (ret == 0)
788 ret = serial;
789 goto okay;
1da177e4
LT
790 }
791
792 /* allow the user to join or create a named keyring */
bb003079 793 mutex_lock(&key_session_mutex);
1da177e4
LT
794
795 /* look for an existing keyring of this name */
69664cf1 796 keyring = find_keyring_by_name(name, false);
1da177e4
LT
797 if (PTR_ERR(keyring) == -ENOKEY) {
798 /* not found - try and create a new one */
96b5c8fe
DH
799 keyring = keyring_alloc(
800 name, old->uid, old->gid, old,
801 KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_LINK,
5ac7eace 802 KEY_ALLOC_IN_QUOTA, NULL, NULL);
1da177e4
LT
803 if (IS_ERR(keyring)) {
804 ret = PTR_ERR(keyring);
bcf945d3 805 goto error2;
1da177e4 806 }
d84f4f99 807 } else if (IS_ERR(keyring)) {
1da177e4
LT
808 ret = PTR_ERR(keyring);
809 goto error2;
3a50597d 810 } else if (keyring == new->session_keyring) {
23567fd0 811 key_put(keyring);
3a50597d
DH
812 ret = 0;
813 goto error2;
1da177e4
LT
814 }
815
816 /* we've got a keyring - now to install it */
d84f4f99 817 ret = install_session_keyring_to_cred(new, keyring);
1da177e4
LT
818 if (ret < 0)
819 goto error2;
820
d84f4f99
DH
821 commit_creds(new);
822 mutex_unlock(&key_session_mutex);
823
1da177e4
LT
824 ret = keyring->serial;
825 key_put(keyring);
d84f4f99
DH
826okay:
827 return ret;
1da177e4 828
664cceb0 829error2:
bb003079 830 mutex_unlock(&key_session_mutex);
664cceb0 831error:
d84f4f99 832 abort_creds(new);
1da177e4 833 return ret;
d84f4f99 834}
ee18d64c
DH
835
836/*
973c9f4f
DH
837 * Replace a process's session keyring on behalf of one of its children when
838 * the target process is about to resume userspace execution.
ee18d64c 839 */
67d12145 840void key_change_session_keyring(struct callback_head *twork)
ee18d64c 841{
413cd3d9 842 const struct cred *old = current_cred();
67d12145 843 struct cred *new = container_of(twork, struct cred, rcu);
ee18d64c 844
413cd3d9
ON
845 if (unlikely(current->flags & PF_EXITING)) {
846 put_cred(new);
ee18d64c 847 return;
413cd3d9 848 }
ee18d64c 849
ee18d64c
DH
850 new-> uid = old-> uid;
851 new-> euid = old-> euid;
852 new-> suid = old-> suid;
853 new->fsuid = old->fsuid;
854 new-> gid = old-> gid;
855 new-> egid = old-> egid;
856 new-> sgid = old-> sgid;
857 new->fsgid = old->fsgid;
858 new->user = get_uid(old->user);
ba0e3427 859 new->user_ns = get_user_ns(old->user_ns);
ee18d64c
DH
860 new->group_info = get_group_info(old->group_info);
861
862 new->securebits = old->securebits;
863 new->cap_inheritable = old->cap_inheritable;
864 new->cap_permitted = old->cap_permitted;
865 new->cap_effective = old->cap_effective;
58319057 866 new->cap_ambient = old->cap_ambient;
ee18d64c
DH
867 new->cap_bset = old->cap_bset;
868
869 new->jit_keyring = old->jit_keyring;
870 new->thread_keyring = key_get(old->thread_keyring);
3a50597d 871 new->process_keyring = key_get(old->process_keyring);
ee18d64c
DH
872
873 security_transfer_creds(new, old);
874
875 commit_creds(new);
876}
c124bde2
MZ
877
878/*
879 * Make sure that root's user and user-session keyrings exist.
880 */
881static int __init init_root_keyring(void)
882{
883 return install_user_keyrings();
884}
885
886late_initcall(init_root_keyring);