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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>
8703e8a4 15#include <linux/sched/user.h>
1da177e4
LT
16#include <linux/keyctl.h>
17#include <linux/fs.h>
18#include <linux/err.h>
bb003079 19#include <linux/mutex.h>
ee18d64c 20#include <linux/security.h>
1d1e9756 21#include <linux/user_namespace.h>
7c0f6ba6 22#include <linux/uaccess.h>
1da177e4
LT
23#include "internal.h"
24
973c9f4f 25/* Session keyring create vs join semaphore */
bb003079 26static DEFINE_MUTEX(key_session_mutex);
1da177e4 27
973c9f4f 28/* User keyring creation semaphore */
69664cf1
DH
29static DEFINE_MUTEX(key_user_keyring_mutex);
30
973c9f4f 31/* The root user's tracking struct */
1da177e4 32struct key_user root_key_user = {
ddb99e11 33 .usage = REFCOUNT_INIT(3),
76181c13 34 .cons_lock = __MUTEX_INITIALIZER(root_key_user.cons_lock),
6cfd76a2 35 .lock = __SPIN_LOCK_UNLOCKED(root_key_user.lock),
1da177e4
LT
36 .nkeys = ATOMIC_INIT(2),
37 .nikeys = ATOMIC_INIT(2),
9a56c2db 38 .uid = GLOBAL_ROOT_UID,
1da177e4
LT
39};
40
1da177e4 41/*
973c9f4f 42 * Install the user and user session keyrings for the current process's UID.
1da177e4 43 */
8bbf4976 44int 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;
9a56c2db 52 uid_t uid;
1da177e4 53
96b5c8fe 54 user_keyring_perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL;
d84f4f99
DH
55 cred = current_cred();
56 user = cred->user;
9a56c2db 57 uid = from_kuid(cred->user_ns, user->uid);
d84f4f99 58
9a56c2db 59 kenter("%p{%u}", user, uid);
1da177e4 60
0da9dfdd 61 if (user->uid_keyring && user->session_keyring) {
69664cf1
DH
62 kleave(" = 0 [exist]");
63 return 0;
1da177e4
LT
64 }
65
69664cf1
DH
66 mutex_lock(&key_user_keyring_mutex);
67 ret = 0;
1da177e4 68
69664cf1
DH
69 if (!user->uid_keyring) {
70 /* get the UID-specific keyring
71 * - there may be one in existence already as it may have been
72 * pinned by a session, but the user_struct pointing to it
73 * may have been destroyed by setuid */
9a56c2db 74 sprintf(buf, "_uid.%u", uid);
69664cf1
DH
75
76 uid_keyring = find_keyring_by_name(buf, true);
77 if (IS_ERR(uid_keyring)) {
9a56c2db 78 uid_keyring = keyring_alloc(buf, user->uid, INVALID_GID,
96b5c8fe 79 cred, user_keyring_perm,
237bbd29
EB
80 KEY_ALLOC_UID_KEYRING |
81 KEY_ALLOC_IN_QUOTA,
5ac7eace 82 NULL, NULL);
69664cf1
DH
83 if (IS_ERR(uid_keyring)) {
84 ret = PTR_ERR(uid_keyring);
85 goto error;
86 }
87 }
88
89 /* get a default session keyring (which might also exist
90 * already) */
9a56c2db 91 sprintf(buf, "_uid_ses.%u", uid);
69664cf1
DH
92
93 session_keyring = find_keyring_by_name(buf, true);
94 if (IS_ERR(session_keyring)) {
95 session_keyring =
9a56c2db 96 keyring_alloc(buf, user->uid, INVALID_GID,
96b5c8fe 97 cred, user_keyring_perm,
237bbd29
EB
98 KEY_ALLOC_UID_KEYRING |
99 KEY_ALLOC_IN_QUOTA,
5ac7eace 100 NULL, NULL);
69664cf1
DH
101 if (IS_ERR(session_keyring)) {
102 ret = PTR_ERR(session_keyring);
103 goto error_release;
104 }
105
106 /* we install a link from the user session keyring to
107 * the user keyring */
108 ret = key_link(session_keyring, uid_keyring);
109 if (ret < 0)
110 goto error_release_both;
111 }
112
113 /* install the keyrings */
114 user->uid_keyring = uid_keyring;
115 user->session_keyring = session_keyring;
1da177e4
LT
116 }
117
69664cf1
DH
118 mutex_unlock(&key_user_keyring_mutex);
119 kleave(" = 0");
120 return 0;
1da177e4 121
69664cf1
DH
122error_release_both:
123 key_put(session_keyring);
124error_release:
125 key_put(uid_keyring);
664cceb0 126error:
69664cf1
DH
127 mutex_unlock(&key_user_keyring_mutex);
128 kleave(" = %d", ret);
1da177e4 129 return ret;
69664cf1 130}
1da177e4 131
1da177e4 132/*
c9f838d1
EB
133 * Install a thread keyring to the given credentials struct if it didn't have
134 * one already. This is allowed to overrun the quota.
135 *
136 * Return: 0 if a thread keyring is now present; -errno on failure.
1da177e4 137 */
d84f4f99 138int install_thread_keyring_to_cred(struct cred *new)
1da177e4 139{
d84f4f99 140 struct key *keyring;
1da177e4 141
c9f838d1
EB
142 if (new->thread_keyring)
143 return 0;
144
d84f4f99 145 keyring = keyring_alloc("_tid", new->uid, new->gid, new,
96b5c8fe 146 KEY_POS_ALL | KEY_USR_VIEW,
5ac7eace
DH
147 KEY_ALLOC_QUOTA_OVERRUN,
148 NULL, NULL);
d84f4f99
DH
149 if (IS_ERR(keyring))
150 return PTR_ERR(keyring);
1da177e4 151
d84f4f99
DH
152 new->thread_keyring = keyring;
153 return 0;
154}
1da177e4 155
1da177e4 156/*
c9f838d1
EB
157 * Install a thread keyring to the current task if it didn't have one already.
158 *
159 * Return: 0 if a thread keyring is now present; -errno on failure.
1da177e4 160 */
d84f4f99 161static int install_thread_keyring(void)
1da177e4 162{
d84f4f99 163 struct cred *new;
1da177e4
LT
164 int ret;
165
d84f4f99
DH
166 new = prepare_creds();
167 if (!new)
168 return -ENOMEM;
1da177e4 169
d84f4f99
DH
170 ret = install_thread_keyring_to_cred(new);
171 if (ret < 0) {
172 abort_creds(new);
173 return ret;
1da177e4
LT
174 }
175
d84f4f99
DH
176 return commit_creds(new);
177}
1da177e4 178
d84f4f99 179/*
c9f838d1
EB
180 * Install a process keyring to the given credentials struct if it didn't have
181 * one already. This is allowed to overrun the quota.
973c9f4f 182 *
c9f838d1 183 * Return: 0 if a process keyring is now present; -errno on failure.
d84f4f99
DH
184 */
185int install_process_keyring_to_cred(struct cred *new)
186{
187 struct key *keyring;
1da177e4 188
3a50597d 189 if (new->process_keyring)
c9f838d1 190 return 0;
d84f4f99 191
96b5c8fe
DH
192 keyring = keyring_alloc("_pid", new->uid, new->gid, new,
193 KEY_POS_ALL | KEY_USR_VIEW,
5ac7eace
DH
194 KEY_ALLOC_QUOTA_OVERRUN,
195 NULL, NULL);
d84f4f99
DH
196 if (IS_ERR(keyring))
197 return PTR_ERR(keyring);
198
3a50597d
DH
199 new->process_keyring = keyring;
200 return 0;
d84f4f99 201}
1da177e4 202
1da177e4 203/*
c9f838d1 204 * Install a process keyring to the current task if it didn't have one already.
973c9f4f 205 *
c9f838d1 206 * Return: 0 if a process keyring is now present; -errno on failure.
1da177e4 207 */
d84f4f99 208static int install_process_keyring(void)
1da177e4 209{
d84f4f99 210 struct cred *new;
1da177e4
LT
211 int ret;
212
d84f4f99
DH
213 new = prepare_creds();
214 if (!new)
215 return -ENOMEM;
1da177e4 216
d84f4f99
DH
217 ret = install_process_keyring_to_cred(new);
218 if (ret < 0) {
219 abort_creds(new);
c9f838d1 220 return ret;
1da177e4
LT
221 }
222
d84f4f99
DH
223 return commit_creds(new);
224}
1da177e4 225
1da177e4 226/*
c9f838d1
EB
227 * Install the given keyring as the session keyring of the given credentials
228 * struct, replacing the existing one if any. If the given keyring is NULL,
229 * then install a new anonymous session keyring.
230 *
231 * Return: 0 on success; -errno on failure.
1da177e4 232 */
685bfd2c 233int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
1da177e4 234{
7e047ef5 235 unsigned long flags;
1da177e4 236 struct key *old;
1a26feb9
DH
237
238 might_sleep();
1da177e4
LT
239
240 /* create an empty session keyring */
241 if (!keyring) {
7e047ef5 242 flags = KEY_ALLOC_QUOTA_OVERRUN;
3a50597d 243 if (cred->session_keyring)
7e047ef5
DH
244 flags = KEY_ALLOC_IN_QUOTA;
245
96b5c8fe
DH
246 keyring = keyring_alloc("_ses", cred->uid, cred->gid, cred,
247 KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ,
5ac7eace 248 flags, NULL, NULL);
1a26feb9
DH
249 if (IS_ERR(keyring))
250 return PTR_ERR(keyring);
d84f4f99 251 } else {
ccc3e6d9 252 __key_get(keyring);
1da177e4
LT
253 }
254
255 /* install the keyring */
3a50597d
DH
256 old = cred->session_keyring;
257 rcu_assign_pointer(cred->session_keyring, keyring);
258
259 if (old)
1a26feb9 260 key_put(old);
1da177e4 261
1a26feb9 262 return 0;
d84f4f99 263}
1da177e4 264
1da177e4 265/*
c9f838d1
EB
266 * Install the given keyring as the session keyring of the current task,
267 * replacing the existing one if any. If the given keyring is NULL, then
268 * install a new anonymous session keyring.
269 *
270 * Return: 0 on success; -errno on failure.
1da177e4 271 */
d84f4f99 272static int install_session_keyring(struct key *keyring)
1da177e4 273{
d84f4f99
DH
274 struct cred *new;
275 int ret;
1da177e4 276
d84f4f99
DH
277 new = prepare_creds();
278 if (!new)
279 return -ENOMEM;
1da177e4 280
99599537 281 ret = install_session_keyring_to_cred(new, keyring);
d84f4f99
DH
282 if (ret < 0) {
283 abort_creds(new);
284 return ret;
285 }
1da177e4 286
d84f4f99
DH
287 return commit_creds(new);
288}
1da177e4 289
1da177e4 290/*
973c9f4f 291 * Handle the fsuid changing.
1da177e4
LT
292 */
293void key_fsuid_changed(struct task_struct *tsk)
294{
295 /* update the ownership of the thread keyring */
b6dff3ec
DH
296 BUG_ON(!tsk->cred);
297 if (tsk->cred->thread_keyring) {
298 down_write(&tsk->cred->thread_keyring->sem);
299 tsk->cred->thread_keyring->uid = tsk->cred->fsuid;
300 up_write(&tsk->cred->thread_keyring->sem);
1da177e4 301 }
a8b17ed0 302}
1da177e4 303
1da177e4 304/*
973c9f4f 305 * Handle the fsgid changing.
1da177e4
LT
306 */
307void key_fsgid_changed(struct task_struct *tsk)
308{
309 /* update the ownership of the thread keyring */
b6dff3ec
DH
310 BUG_ON(!tsk->cred);
311 if (tsk->cred->thread_keyring) {
312 down_write(&tsk->cred->thread_keyring->sem);
313 tsk->cred->thread_keyring->gid = tsk->cred->fsgid;
314 up_write(&tsk->cred->thread_keyring->sem);
1da177e4 315 }
a8b17ed0 316}
1da177e4 317
1da177e4 318/*
973c9f4f
DH
319 * Search the process keyrings attached to the supplied cred for the first
320 * matching key.
321 *
322 * The search criteria are the type and the match function. The description is
323 * given to the match function as a parameter, but doesn't otherwise influence
324 * the search. Typically the match function will compare the description
325 * parameter to the key's description.
326 *
327 * This can only search keyrings that grant Search permission to the supplied
328 * credentials. Keyrings linked to searched keyrings will also be searched if
329 * they grant Search permission too. Keys can only be found if they grant
330 * Search permission to the credentials.
331 *
332 * Returns a pointer to the key with the key usage count incremented if
333 * successful, -EAGAIN if we didn't find any matching key or -ENOKEY if we only
334 * matched negative keys.
335 *
336 * In the case of a successful return, the possession attribute is set on the
337 * returned key reference.
1da177e4 338 */
4bdf0bc3 339key_ref_t search_my_process_keyrings(struct keyring_search_context *ctx)
1da177e4 340{
b5f545c8 341 key_ref_t key_ref, ret, err;
1da177e4
LT
342
343 /* we want to return -EAGAIN or -ENOKEY if any of the keyrings were
344 * searchable, but we failed to find a key or we found a negative key;
345 * otherwise we want to return a sample error (probably -EACCES) if
346 * none of the keyrings were searchable
347 *
348 * in terms of priority: success > -ENOKEY > -EAGAIN > other error
349 */
664cceb0 350 key_ref = NULL;
1da177e4
LT
351 ret = NULL;
352 err = ERR_PTR(-EAGAIN);
353
354 /* search the thread keyring first */
4bdf0bc3 355 if (ctx->cred->thread_keyring) {
664cceb0 356 key_ref = keyring_search_aux(
4bdf0bc3 357 make_key_ref(ctx->cred->thread_keyring, 1), ctx);
664cceb0 358 if (!IS_ERR(key_ref))
1da177e4
LT
359 goto found;
360
664cceb0 361 switch (PTR_ERR(key_ref)) {
1da177e4 362 case -EAGAIN: /* no key */
1da177e4 363 case -ENOKEY: /* negative key */
664cceb0 364 ret = key_ref;
1da177e4
LT
365 break;
366 default:
664cceb0 367 err = key_ref;
1da177e4
LT
368 break;
369 }
370 }
371
372 /* search the process keyring second */
4bdf0bc3 373 if (ctx->cred->process_keyring) {
664cceb0 374 key_ref = keyring_search_aux(
4bdf0bc3 375 make_key_ref(ctx->cred->process_keyring, 1), ctx);
664cceb0 376 if (!IS_ERR(key_ref))
1da177e4
LT
377 goto found;
378
664cceb0 379 switch (PTR_ERR(key_ref)) {
1da177e4 380 case -EAGAIN: /* no key */
fe9453a1
DH
381 if (ret)
382 break;
1da177e4 383 case -ENOKEY: /* negative key */
664cceb0 384 ret = key_ref;
1da177e4
LT
385 break;
386 default:
664cceb0 387 err = key_ref;
1da177e4
LT
388 break;
389 }
390 }
391
3e30148c 392 /* search the session keyring */
4bdf0bc3 393 if (ctx->cred->session_keyring) {
8589b4e0 394 rcu_read_lock();
664cceb0 395 key_ref = keyring_search_aux(
4bdf0bc3
DH
396 make_key_ref(rcu_dereference(ctx->cred->session_keyring), 1),
397 ctx);
8589b4e0 398 rcu_read_unlock();
3e30148c 399
664cceb0 400 if (!IS_ERR(key_ref))
3e30148c
DH
401 goto found;
402
664cceb0 403 switch (PTR_ERR(key_ref)) {
3e30148c
DH
404 case -EAGAIN: /* no key */
405 if (ret)
406 break;
407 case -ENOKEY: /* negative key */
664cceb0 408 ret = key_ref;
3e30148c
DH
409 break;
410 default:
664cceb0 411 err = key_ref;
3e30148c
DH
412 break;
413 }
b5f545c8
DH
414 }
415 /* or search the user-session keyring */
4bdf0bc3 416 else if (ctx->cred->user->session_keyring) {
b5f545c8 417 key_ref = keyring_search_aux(
4bdf0bc3
DH
418 make_key_ref(ctx->cred->user->session_keyring, 1),
419 ctx);
664cceb0 420 if (!IS_ERR(key_ref))
3e30148c
DH
421 goto found;
422
664cceb0 423 switch (PTR_ERR(key_ref)) {
3e30148c
DH
424 case -EAGAIN: /* no key */
425 if (ret)
426 break;
427 case -ENOKEY: /* negative key */
664cceb0 428 ret = key_ref;
3e30148c
DH
429 break;
430 default:
664cceb0 431 err = key_ref;
3e30148c
DH
432 break;
433 }
8589b4e0 434 }
b5f545c8 435
927942aa
DH
436 /* no key - decide on the error we're going to go for */
437 key_ref = ret ? ret : err;
438
439found:
440 return key_ref;
441}
442
927942aa 443/*
973c9f4f
DH
444 * Search the process keyrings attached to the supplied cred for the first
445 * matching key in the manner of search_my_process_keyrings(), but also search
446 * the keys attached to the assumed authorisation key using its credentials if
447 * one is available.
448 *
449 * Return same as search_my_process_keyrings().
927942aa 450 */
4bdf0bc3 451key_ref_t search_process_keyrings(struct keyring_search_context *ctx)
927942aa
DH
452{
453 struct request_key_auth *rka;
454 key_ref_t key_ref, ret = ERR_PTR(-EACCES), err;
455
456 might_sleep();
457
4bdf0bc3 458 key_ref = search_my_process_keyrings(ctx);
927942aa
DH
459 if (!IS_ERR(key_ref))
460 goto found;
461 err = key_ref;
462
b5f545c8
DH
463 /* if this process has an instantiation authorisation key, then we also
464 * search the keyrings of the process mentioned there
465 * - we don't permit access to request_key auth keys via this method
466 */
4bdf0bc3
DH
467 if (ctx->cred->request_key_auth &&
468 ctx->cred == current_cred() &&
469 ctx->index_key.type != &key_type_request_key_auth
b5f545c8 470 ) {
4bdf0bc3
DH
471 const struct cred *cred = ctx->cred;
472
04c567d9 473 /* defend against the auth key being revoked */
c69e8d9c 474 down_read(&cred->request_key_auth->sem);
b5f545c8 475
4bdf0bc3 476 if (key_validate(ctx->cred->request_key_auth) == 0) {
146aa8b1 477 rka = ctx->cred->request_key_auth->payload.data[0];
b5f545c8 478
4bdf0bc3
DH
479 ctx->cred = rka->cred;
480 key_ref = search_process_keyrings(ctx);
481 ctx->cred = cred;
1da177e4 482
c69e8d9c 483 up_read(&cred->request_key_auth->sem);
04c567d9
DH
484
485 if (!IS_ERR(key_ref))
486 goto found;
487
927942aa 488 ret = key_ref;
04c567d9 489 } else {
c69e8d9c 490 up_read(&cred->request_key_auth->sem);
3e30148c 491 }
1da177e4
LT
492 }
493
494 /* no key - decide on the error we're going to go for */
927942aa
DH
495 if (err == ERR_PTR(-ENOKEY) || ret == ERR_PTR(-ENOKEY))
496 key_ref = ERR_PTR(-ENOKEY);
497 else if (err == ERR_PTR(-EACCES))
498 key_ref = ret;
499 else
500 key_ref = err;
1da177e4 501
3e30148c 502found:
664cceb0 503 return key_ref;
a8b17ed0 504}
1da177e4 505
664cceb0 506/*
973c9f4f 507 * See if the key we're looking at is the target key.
664cceb0 508 */
0c903ab6
DH
509bool lookup_user_key_possessed(const struct key *key,
510 const struct key_match_data *match_data)
664cceb0 511{
46291959 512 return key == match_data->raw_data;
a8b17ed0 513}
664cceb0 514
1da177e4 515/*
973c9f4f
DH
516 * Look up a key ID given us by userspace with a given permissions mask to get
517 * the key it refers to.
518 *
519 * Flags can be passed to request that special keyrings be created if referred
520 * to directly, to permit partially constructed keys to be found and to skip
521 * validity and permission checks on the found key.
522 *
523 * Returns a pointer to the key with an incremented usage count if successful;
524 * -EINVAL if the key ID is invalid; -ENOKEY if the key ID does not correspond
525 * to a key or the best found key was a negative key; -EKEYREVOKED or
526 * -EKEYEXPIRED if the best found key was revoked or expired; -EACCES if the
527 * found key doesn't grant the requested permit or the LSM denied access to it;
528 * or -ENOMEM if a special keyring couldn't be created.
529 *
530 * In the case of a successful return, the possession attribute is set on the
531 * returned key reference.
1da177e4 532 */
5593122e 533key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
8bbf4976 534 key_perm_t perm)
1da177e4 535{
4bdf0bc3 536 struct keyring_search_context ctx = {
46291959
DH
537 .match_data.cmp = lookup_user_key_possessed,
538 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
539 .flags = KEYRING_SEARCH_NO_STATE_CHECK,
4bdf0bc3 540 };
8bbf4976 541 struct request_key_auth *rka;
1da177e4 542 struct key *key;
b6dff3ec 543 key_ref_t key_ref, skey_ref;
1da177e4
LT
544 int ret;
545
bb952bb9 546try_again:
4bdf0bc3 547 ctx.cred = get_current_cred();
664cceb0 548 key_ref = ERR_PTR(-ENOKEY);
1da177e4
LT
549
550 switch (id) {
551 case KEY_SPEC_THREAD_KEYRING:
4bdf0bc3 552 if (!ctx.cred->thread_keyring) {
5593122e 553 if (!(lflags & KEY_LOOKUP_CREATE))
1da177e4
LT
554 goto error;
555
8bbf4976 556 ret = install_thread_keyring();
1da177e4 557 if (ret < 0) {
4d09ec0f 558 key_ref = ERR_PTR(ret);
1da177e4
LT
559 goto error;
560 }
bb952bb9 561 goto reget_creds;
1da177e4
LT
562 }
563
4bdf0bc3 564 key = ctx.cred->thread_keyring;
ccc3e6d9 565 __key_get(key);
664cceb0 566 key_ref = make_key_ref(key, 1);
1da177e4
LT
567 break;
568
569 case KEY_SPEC_PROCESS_KEYRING:
4bdf0bc3 570 if (!ctx.cred->process_keyring) {
5593122e 571 if (!(lflags & KEY_LOOKUP_CREATE))
1da177e4
LT
572 goto error;
573
8bbf4976 574 ret = install_process_keyring();
1da177e4 575 if (ret < 0) {
4d09ec0f 576 key_ref = ERR_PTR(ret);
1da177e4
LT
577 goto error;
578 }
bb952bb9 579 goto reget_creds;
1da177e4
LT
580 }
581
4bdf0bc3 582 key = ctx.cred->process_keyring;
ccc3e6d9 583 __key_get(key);
664cceb0 584 key_ref = make_key_ref(key, 1);
1da177e4
LT
585 break;
586
587 case KEY_SPEC_SESSION_KEYRING:
4bdf0bc3 588 if (!ctx.cred->session_keyring) {
1da177e4
LT
589 /* always install a session keyring upon access if one
590 * doesn't exist yet */
8bbf4976 591 ret = install_user_keyrings();
69664cf1
DH
592 if (ret < 0)
593 goto error;
3ecf1b4f
DH
594 if (lflags & KEY_LOOKUP_CREATE)
595 ret = join_session_keyring(NULL);
596 else
597 ret = install_session_keyring(
4bdf0bc3 598 ctx.cred->user->session_keyring);
d84f4f99 599
1da177e4
LT
600 if (ret < 0)
601 goto error;
bb952bb9 602 goto reget_creds;
4bdf0bc3
DH
603 } else if (ctx.cred->session_keyring ==
604 ctx.cred->user->session_keyring &&
3ecf1b4f
DH
605 lflags & KEY_LOOKUP_CREATE) {
606 ret = join_session_keyring(NULL);
607 if (ret < 0)
608 goto error;
609 goto reget_creds;
1da177e4
LT
610 }
611
3e30148c 612 rcu_read_lock();
4bdf0bc3 613 key = rcu_dereference(ctx.cred->session_keyring);
ccc3e6d9 614 __key_get(key);
3e30148c 615 rcu_read_unlock();
664cceb0 616 key_ref = make_key_ref(key, 1);
1da177e4
LT
617 break;
618
619 case KEY_SPEC_USER_KEYRING:
4bdf0bc3 620 if (!ctx.cred->user->uid_keyring) {
8bbf4976 621 ret = install_user_keyrings();
69664cf1
DH
622 if (ret < 0)
623 goto error;
624 }
625
4bdf0bc3 626 key = ctx.cred->user->uid_keyring;
ccc3e6d9 627 __key_get(key);
664cceb0 628 key_ref = make_key_ref(key, 1);
1da177e4
LT
629 break;
630
631 case KEY_SPEC_USER_SESSION_KEYRING:
4bdf0bc3 632 if (!ctx.cred->user->session_keyring) {
8bbf4976 633 ret = install_user_keyrings();
69664cf1
DH
634 if (ret < 0)
635 goto error;
636 }
637
4bdf0bc3 638 key = ctx.cred->user->session_keyring;
ccc3e6d9 639 __key_get(key);
664cceb0 640 key_ref = make_key_ref(key, 1);
1da177e4
LT
641 break;
642
643 case KEY_SPEC_GROUP_KEYRING:
644 /* group keyrings are not yet supported */
4d09ec0f 645 key_ref = ERR_PTR(-EINVAL);
1da177e4
LT
646 goto error;
647
b5f545c8 648 case KEY_SPEC_REQKEY_AUTH_KEY:
4bdf0bc3 649 key = ctx.cred->request_key_auth;
b5f545c8
DH
650 if (!key)
651 goto error;
652
ccc3e6d9 653 __key_get(key);
b5f545c8
DH
654 key_ref = make_key_ref(key, 1);
655 break;
656
8bbf4976 657 case KEY_SPEC_REQUESTOR_KEYRING:
4bdf0bc3 658 if (!ctx.cred->request_key_auth)
8bbf4976
DH
659 goto error;
660
4bdf0bc3 661 down_read(&ctx.cred->request_key_auth->sem);
f67dabbd 662 if (test_bit(KEY_FLAG_REVOKED,
4bdf0bc3 663 &ctx.cred->request_key_auth->flags)) {
8bbf4976
DH
664 key_ref = ERR_PTR(-EKEYREVOKED);
665 key = NULL;
666 } else {
146aa8b1 667 rka = ctx.cred->request_key_auth->payload.data[0];
8bbf4976 668 key = rka->dest_keyring;
ccc3e6d9 669 __key_get(key);
8bbf4976 670 }
4bdf0bc3 671 up_read(&ctx.cred->request_key_auth->sem);
8bbf4976
DH
672 if (!key)
673 goto error;
674 key_ref = make_key_ref(key, 1);
675 break;
676
1da177e4 677 default:
664cceb0 678 key_ref = ERR_PTR(-EINVAL);
1da177e4
LT
679 if (id < 1)
680 goto error;
681
682 key = key_lookup(id);
664cceb0 683 if (IS_ERR(key)) {
e231c2ee 684 key_ref = ERR_CAST(key);
1da177e4 685 goto error;
664cceb0
DH
686 }
687
688 key_ref = make_key_ref(key, 0);
689
690 /* check to see if we possess the key */
4bdf0bc3
DH
691 ctx.index_key.type = key->type;
692 ctx.index_key.description = key->description;
693 ctx.index_key.desc_len = strlen(key->description);
46291959 694 ctx.match_data.raw_data = key;
4bdf0bc3
DH
695 kdebug("check possessed");
696 skey_ref = search_process_keyrings(&ctx);
697 kdebug("possessed=%p", skey_ref);
664cceb0
DH
698
699 if (!IS_ERR(skey_ref)) {
700 key_put(key);
701 key_ref = skey_ref;
702 }
703
1da177e4
LT
704 break;
705 }
706
5593122e
DH
707 /* unlink does not use the nominated key in any way, so can skip all
708 * the permission checks as it is only concerned with the keyring */
709 if (lflags & KEY_LOOKUP_FOR_UNLINK) {
710 ret = 0;
711 goto error;
712 }
713
714 if (!(lflags & KEY_LOOKUP_PARTIAL)) {
76181c13
DH
715 ret = wait_for_key_construction(key, true);
716 switch (ret) {
717 case -ERESTARTSYS:
718 goto invalid_key;
719 default:
720 if (perm)
721 goto invalid_key;
722 case 0:
723 break;
724 }
725 } else if (perm) {
1da177e4
LT
726 ret = key_validate(key);
727 if (ret < 0)
728 goto invalid_key;
729 }
730
731 ret = -EIO;
5593122e 732 if (!(lflags & KEY_LOOKUP_PARTIAL) &&
363b02da 733 key_read_state(key) == KEY_IS_UNINSTANTIATED)
1da177e4
LT
734 goto invalid_key;
735
3e30148c 736 /* check the permissions */
4bdf0bc3 737 ret = key_task_permission(key_ref, ctx.cred, perm);
29db9190 738 if (ret < 0)
1da177e4
LT
739 goto invalid_key;
740
074d5898 741 key->last_used_at = ktime_get_real_seconds();
31d5a79d 742
664cceb0 743error:
4bdf0bc3 744 put_cred(ctx.cred);
664cceb0 745 return key_ref;
1da177e4 746
664cceb0
DH
747invalid_key:
748 key_ref_put(key_ref);
749 key_ref = ERR_PTR(ret);
1da177e4
LT
750 goto error;
751
bb952bb9
DH
752 /* if we attempted to install a keyring, then it may have caused new
753 * creds to be installed */
754reget_creds:
4bdf0bc3 755 put_cred(ctx.cred);
bb952bb9 756 goto try_again;
a8b17ed0 757}
bb952bb9 758
1da177e4 759/*
973c9f4f
DH
760 * Join the named keyring as the session keyring if possible else attempt to
761 * create a new one of that name and join that.
762 *
763 * If the name is NULL, an empty anonymous keyring will be installed as the
764 * session keyring.
765 *
766 * Named session keyrings are joined with a semaphore held to prevent the
767 * keyrings from going away whilst the attempt is made to going them and also
768 * to prevent a race in creating compatible session keyrings.
1da177e4
LT
769 */
770long join_session_keyring(const char *name)
771{
d84f4f99
DH
772 const struct cred *old;
773 struct cred *new;
1da177e4 774 struct key *keyring;
d84f4f99
DH
775 long ret, serial;
776
d84f4f99
DH
777 new = prepare_creds();
778 if (!new)
779 return -ENOMEM;
780 old = current_cred();
1da177e4
LT
781
782 /* if no name is provided, install an anonymous keyring */
783 if (!name) {
d84f4f99 784 ret = install_session_keyring_to_cred(new, NULL);
1da177e4
LT
785 if (ret < 0)
786 goto error;
787
3a50597d 788 serial = new->session_keyring->serial;
d84f4f99
DH
789 ret = commit_creds(new);
790 if (ret == 0)
791 ret = serial;
792 goto okay;
1da177e4
LT
793 }
794
795 /* allow the user to join or create a named keyring */
bb003079 796 mutex_lock(&key_session_mutex);
1da177e4
LT
797
798 /* look for an existing keyring of this name */
69664cf1 799 keyring = find_keyring_by_name(name, false);
1da177e4
LT
800 if (PTR_ERR(keyring) == -ENOKEY) {
801 /* not found - try and create a new one */
96b5c8fe
DH
802 keyring = keyring_alloc(
803 name, old->uid, old->gid, old,
804 KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_LINK,
5ac7eace 805 KEY_ALLOC_IN_QUOTA, NULL, NULL);
1da177e4
LT
806 if (IS_ERR(keyring)) {
807 ret = PTR_ERR(keyring);
bcf945d3 808 goto error2;
1da177e4 809 }
d84f4f99 810 } else if (IS_ERR(keyring)) {
1da177e4
LT
811 ret = PTR_ERR(keyring);
812 goto error2;
3a50597d
DH
813 } else if (keyring == new->session_keyring) {
814 ret = 0;
d636bd9f 815 goto error3;
1da177e4
LT
816 }
817
818 /* we've got a keyring - now to install it */
d84f4f99 819 ret = install_session_keyring_to_cred(new, keyring);
1da177e4 820 if (ret < 0)
d636bd9f 821 goto error3;
1da177e4 822
d84f4f99
DH
823 commit_creds(new);
824 mutex_unlock(&key_session_mutex);
825
1da177e4
LT
826 ret = keyring->serial;
827 key_put(keyring);
d84f4f99
DH
828okay:
829 return ret;
1da177e4 830
d636bd9f
EB
831error3:
832 key_put(keyring);
664cceb0 833error2:
bb003079 834 mutex_unlock(&key_session_mutex);
664cceb0 835error:
d84f4f99 836 abort_creds(new);
1da177e4 837 return ret;
d84f4f99 838}
ee18d64c
DH
839
840/*
973c9f4f
DH
841 * Replace a process's session keyring on behalf of one of its children when
842 * the target process is about to resume userspace execution.
ee18d64c 843 */
67d12145 844void key_change_session_keyring(struct callback_head *twork)
ee18d64c 845{
413cd3d9 846 const struct cred *old = current_cred();
67d12145 847 struct cred *new = container_of(twork, struct cred, rcu);
ee18d64c 848
413cd3d9
ON
849 if (unlikely(current->flags & PF_EXITING)) {
850 put_cred(new);
ee18d64c 851 return;
413cd3d9 852 }
ee18d64c 853
ee18d64c
DH
854 new-> uid = old-> uid;
855 new-> euid = old-> euid;
856 new-> suid = old-> suid;
857 new->fsuid = old->fsuid;
858 new-> gid = old-> gid;
859 new-> egid = old-> egid;
860 new-> sgid = old-> sgid;
861 new->fsgid = old->fsgid;
862 new->user = get_uid(old->user);
ba0e3427 863 new->user_ns = get_user_ns(old->user_ns);
ee18d64c
DH
864 new->group_info = get_group_info(old->group_info);
865
866 new->securebits = old->securebits;
867 new->cap_inheritable = old->cap_inheritable;
868 new->cap_permitted = old->cap_permitted;
869 new->cap_effective = old->cap_effective;
58319057 870 new->cap_ambient = old->cap_ambient;
ee18d64c
DH
871 new->cap_bset = old->cap_bset;
872
873 new->jit_keyring = old->jit_keyring;
874 new->thread_keyring = key_get(old->thread_keyring);
3a50597d 875 new->process_keyring = key_get(old->process_keyring);
ee18d64c
DH
876
877 security_transfer_creds(new, old);
878
879 commit_creds(new);
880}
c124bde2
MZ
881
882/*
883 * Make sure that root's user and user-session keyrings exist.
884 */
885static int __init init_root_keyring(void)
886{
887 return install_user_keyrings();
888}
889
890late_initcall(init_root_keyring);