Merge branch 'thorsten' into docs-next
[linux-2.6-block.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
1da177e4
LT
12#include <linux/init.h>
13#include <linux/sched.h>
8703e8a4 14#include <linux/sched/user.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 31struct key_user root_key_user = {
ddb99e11 32 .usage = REFCOUNT_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,
237bbd29
EB
79 KEY_ALLOC_UID_KEYRING |
80 KEY_ALLOC_IN_QUOTA,
5ac7eace 81 NULL, NULL);
69664cf1
DH
82 if (IS_ERR(uid_keyring)) {
83 ret = PTR_ERR(uid_keyring);
84 goto error;
85 }
86 }
87
88 /* get a default session keyring (which might also exist
89 * already) */
9a56c2db 90 sprintf(buf, "_uid_ses.%u", uid);
69664cf1
DH
91
92 session_keyring = find_keyring_by_name(buf, true);
93 if (IS_ERR(session_keyring)) {
94 session_keyring =
9a56c2db 95 keyring_alloc(buf, user->uid, INVALID_GID,
96b5c8fe 96 cred, user_keyring_perm,
237bbd29
EB
97 KEY_ALLOC_UID_KEYRING |
98 KEY_ALLOC_IN_QUOTA,
5ac7eace 99 NULL, NULL);
69664cf1
DH
100 if (IS_ERR(session_keyring)) {
101 ret = PTR_ERR(session_keyring);
102 goto error_release;
103 }
104
105 /* we install a link from the user session keyring to
106 * the user keyring */
107 ret = key_link(session_keyring, uid_keyring);
108 if (ret < 0)
109 goto error_release_both;
110 }
111
112 /* install the keyrings */
113 user->uid_keyring = uid_keyring;
114 user->session_keyring = session_keyring;
1da177e4
LT
115 }
116
69664cf1
DH
117 mutex_unlock(&key_user_keyring_mutex);
118 kleave(" = 0");
119 return 0;
1da177e4 120
69664cf1
DH
121error_release_both:
122 key_put(session_keyring);
123error_release:
124 key_put(uid_keyring);
664cceb0 125error:
69664cf1
DH
126 mutex_unlock(&key_user_keyring_mutex);
127 kleave(" = %d", ret);
1da177e4 128 return ret;
69664cf1 129}
1da177e4 130
1da177e4 131/*
c9f838d1
EB
132 * Install a thread keyring to the given credentials struct if it didn't have
133 * one already. This is allowed to overrun the quota.
134 *
135 * Return: 0 if a thread keyring is now present; -errno on failure.
1da177e4 136 */
d84f4f99 137int install_thread_keyring_to_cred(struct cred *new)
1da177e4 138{
d84f4f99 139 struct key *keyring;
1da177e4 140
c9f838d1
EB
141 if (new->thread_keyring)
142 return 0;
143
d84f4f99 144 keyring = keyring_alloc("_tid", new->uid, new->gid, new,
96b5c8fe 145 KEY_POS_ALL | KEY_USR_VIEW,
5ac7eace
DH
146 KEY_ALLOC_QUOTA_OVERRUN,
147 NULL, NULL);
d84f4f99
DH
148 if (IS_ERR(keyring))
149 return PTR_ERR(keyring);
1da177e4 150
d84f4f99
DH
151 new->thread_keyring = keyring;
152 return 0;
153}
1da177e4 154
1da177e4 155/*
c9f838d1
EB
156 * Install a thread keyring to the current task if it didn't have one already.
157 *
158 * Return: 0 if a thread keyring is now present; -errno on failure.
1da177e4 159 */
d84f4f99 160static int install_thread_keyring(void)
1da177e4 161{
d84f4f99 162 struct cred *new;
1da177e4
LT
163 int ret;
164
d84f4f99
DH
165 new = prepare_creds();
166 if (!new)
167 return -ENOMEM;
1da177e4 168
d84f4f99
DH
169 ret = install_thread_keyring_to_cred(new);
170 if (ret < 0) {
171 abort_creds(new);
172 return ret;
1da177e4
LT
173 }
174
d84f4f99
DH
175 return commit_creds(new);
176}
1da177e4 177
d84f4f99 178/*
c9f838d1
EB
179 * Install a process keyring to the given credentials struct if it didn't have
180 * one already. This is allowed to overrun the quota.
973c9f4f 181 *
c9f838d1 182 * Return: 0 if a process keyring is now present; -errno on failure.
d84f4f99
DH
183 */
184int install_process_keyring_to_cred(struct cred *new)
185{
186 struct key *keyring;
1da177e4 187
3a50597d 188 if (new->process_keyring)
c9f838d1 189 return 0;
d84f4f99 190
96b5c8fe
DH
191 keyring = keyring_alloc("_pid", new->uid, new->gid, new,
192 KEY_POS_ALL | KEY_USR_VIEW,
5ac7eace
DH
193 KEY_ALLOC_QUOTA_OVERRUN,
194 NULL, NULL);
d84f4f99
DH
195 if (IS_ERR(keyring))
196 return PTR_ERR(keyring);
197
3a50597d
DH
198 new->process_keyring = keyring;
199 return 0;
d84f4f99 200}
1da177e4 201
1da177e4 202/*
c9f838d1 203 * Install a process keyring to the current task if it didn't have one already.
973c9f4f 204 *
c9f838d1 205 * Return: 0 if a process keyring is now present; -errno on failure.
1da177e4 206 */
d84f4f99 207static int install_process_keyring(void)
1da177e4 208{
d84f4f99 209 struct cred *new;
1da177e4
LT
210 int ret;
211
d84f4f99
DH
212 new = prepare_creds();
213 if (!new)
214 return -ENOMEM;
1da177e4 215
d84f4f99
DH
216 ret = install_process_keyring_to_cred(new);
217 if (ret < 0) {
218 abort_creds(new);
c9f838d1 219 return ret;
1da177e4
LT
220 }
221
d84f4f99
DH
222 return commit_creds(new);
223}
1da177e4 224
1da177e4 225/*
c9f838d1
EB
226 * Install the given keyring as the session keyring of the given credentials
227 * struct, replacing the existing one if any. If the given keyring is NULL,
228 * then install a new anonymous session keyring.
229 *
230 * Return: 0 on success; -errno on failure.
1da177e4 231 */
685bfd2c 232int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
1da177e4 233{
7e047ef5 234 unsigned long flags;
1da177e4 235 struct key *old;
1a26feb9
DH
236
237 might_sleep();
1da177e4
LT
238
239 /* create an empty session keyring */
240 if (!keyring) {
7e047ef5 241 flags = KEY_ALLOC_QUOTA_OVERRUN;
3a50597d 242 if (cred->session_keyring)
7e047ef5
DH
243 flags = KEY_ALLOC_IN_QUOTA;
244
96b5c8fe
DH
245 keyring = keyring_alloc("_ses", cred->uid, cred->gid, cred,
246 KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ,
5ac7eace 247 flags, NULL, NULL);
1a26feb9
DH
248 if (IS_ERR(keyring))
249 return PTR_ERR(keyring);
d84f4f99 250 } else {
ccc3e6d9 251 __key_get(keyring);
1da177e4
LT
252 }
253
254 /* install the keyring */
3a50597d
DH
255 old = cred->session_keyring;
256 rcu_assign_pointer(cred->session_keyring, keyring);
257
258 if (old)
1a26feb9 259 key_put(old);
1da177e4 260
1a26feb9 261 return 0;
d84f4f99 262}
1da177e4 263
1da177e4 264/*
c9f838d1
EB
265 * Install the given keyring as the session keyring of the current task,
266 * replacing the existing one if any. If the given keyring is NULL, then
267 * install a new anonymous session keyring.
268 *
269 * Return: 0 on success; -errno on failure.
1da177e4 270 */
d84f4f99 271static int install_session_keyring(struct key *keyring)
1da177e4 272{
d84f4f99
DH
273 struct cred *new;
274 int ret;
1da177e4 275
d84f4f99
DH
276 new = prepare_creds();
277 if (!new)
278 return -ENOMEM;
1da177e4 279
99599537 280 ret = install_session_keyring_to_cred(new, keyring);
d84f4f99
DH
281 if (ret < 0) {
282 abort_creds(new);
283 return ret;
284 }
1da177e4 285
d84f4f99
DH
286 return commit_creds(new);
287}
1da177e4 288
1da177e4 289/*
973c9f4f 290 * Handle the fsuid changing.
1da177e4
LT
291 */
292void key_fsuid_changed(struct task_struct *tsk)
293{
294 /* update the ownership of the thread keyring */
b6dff3ec
DH
295 BUG_ON(!tsk->cred);
296 if (tsk->cred->thread_keyring) {
297 down_write(&tsk->cred->thread_keyring->sem);
298 tsk->cred->thread_keyring->uid = tsk->cred->fsuid;
299 up_write(&tsk->cred->thread_keyring->sem);
1da177e4 300 }
a8b17ed0 301}
1da177e4 302
1da177e4 303/*
973c9f4f 304 * Handle the fsgid changing.
1da177e4
LT
305 */
306void key_fsgid_changed(struct task_struct *tsk)
307{
308 /* update the ownership of the thread keyring */
b6dff3ec
DH
309 BUG_ON(!tsk->cred);
310 if (tsk->cred->thread_keyring) {
311 down_write(&tsk->cred->thread_keyring->sem);
312 tsk->cred->thread_keyring->gid = tsk->cred->fsgid;
313 up_write(&tsk->cred->thread_keyring->sem);
1da177e4 314 }
a8b17ed0 315}
1da177e4 316
1da177e4 317/*
973c9f4f
DH
318 * Search the process keyrings attached to the supplied cred for the first
319 * matching key.
320 *
321 * The search criteria are the type and the match function. The description is
322 * given to the match function as a parameter, but doesn't otherwise influence
323 * the search. Typically the match function will compare the description
324 * parameter to the key's description.
325 *
326 * This can only search keyrings that grant Search permission to the supplied
327 * credentials. Keyrings linked to searched keyrings will also be searched if
328 * they grant Search permission too. Keys can only be found if they grant
329 * Search permission to the credentials.
330 *
331 * Returns a pointer to the key with the key usage count incremented if
332 * successful, -EAGAIN if we didn't find any matching key or -ENOKEY if we only
333 * matched negative keys.
334 *
335 * In the case of a successful return, the possession attribute is set on the
336 * returned key reference.
1da177e4 337 */
4bdf0bc3 338key_ref_t search_my_process_keyrings(struct keyring_search_context *ctx)
1da177e4 339{
b5f545c8 340 key_ref_t key_ref, ret, err;
1da177e4
LT
341
342 /* we want to return -EAGAIN or -ENOKEY if any of the keyrings were
343 * searchable, but we failed to find a key or we found a negative key;
344 * otherwise we want to return a sample error (probably -EACCES) if
345 * none of the keyrings were searchable
346 *
347 * in terms of priority: success > -ENOKEY > -EAGAIN > other error
348 */
664cceb0 349 key_ref = NULL;
1da177e4
LT
350 ret = NULL;
351 err = ERR_PTR(-EAGAIN);
352
353 /* search the thread keyring first */
4bdf0bc3 354 if (ctx->cred->thread_keyring) {
664cceb0 355 key_ref = keyring_search_aux(
4bdf0bc3 356 make_key_ref(ctx->cred->thread_keyring, 1), ctx);
664cceb0 357 if (!IS_ERR(key_ref))
1da177e4
LT
358 goto found;
359
664cceb0 360 switch (PTR_ERR(key_ref)) {
1da177e4 361 case -EAGAIN: /* no key */
1da177e4 362 case -ENOKEY: /* negative key */
664cceb0 363 ret = key_ref;
1da177e4
LT
364 break;
365 default:
664cceb0 366 err = key_ref;
1da177e4
LT
367 break;
368 }
369 }
370
371 /* search the process keyring second */
4bdf0bc3 372 if (ctx->cred->process_keyring) {
664cceb0 373 key_ref = keyring_search_aux(
4bdf0bc3 374 make_key_ref(ctx->cred->process_keyring, 1), ctx);
664cceb0 375 if (!IS_ERR(key_ref))
1da177e4
LT
376 goto found;
377
664cceb0 378 switch (PTR_ERR(key_ref)) {
1da177e4 379 case -EAGAIN: /* no key */
fe9453a1
DH
380 if (ret)
381 break;
1da177e4 382 case -ENOKEY: /* negative key */
664cceb0 383 ret = key_ref;
1da177e4
LT
384 break;
385 default:
664cceb0 386 err = key_ref;
1da177e4
LT
387 break;
388 }
389 }
390
3e30148c 391 /* search the session keyring */
4bdf0bc3 392 if (ctx->cred->session_keyring) {
8589b4e0 393 rcu_read_lock();
664cceb0 394 key_ref = keyring_search_aux(
4bdf0bc3
DH
395 make_key_ref(rcu_dereference(ctx->cred->session_keyring), 1),
396 ctx);
8589b4e0 397 rcu_read_unlock();
3e30148c 398
664cceb0 399 if (!IS_ERR(key_ref))
3e30148c
DH
400 goto found;
401
664cceb0 402 switch (PTR_ERR(key_ref)) {
3e30148c
DH
403 case -EAGAIN: /* no key */
404 if (ret)
405 break;
406 case -ENOKEY: /* negative key */
664cceb0 407 ret = key_ref;
3e30148c
DH
408 break;
409 default:
664cceb0 410 err = key_ref;
3e30148c
DH
411 break;
412 }
b5f545c8
DH
413 }
414 /* or search the user-session keyring */
4bdf0bc3 415 else if (ctx->cred->user->session_keyring) {
b5f545c8 416 key_ref = keyring_search_aux(
4bdf0bc3
DH
417 make_key_ref(ctx->cred->user->session_keyring, 1),
418 ctx);
664cceb0 419 if (!IS_ERR(key_ref))
3e30148c
DH
420 goto found;
421
664cceb0 422 switch (PTR_ERR(key_ref)) {
3e30148c
DH
423 case -EAGAIN: /* no key */
424 if (ret)
425 break;
426 case -ENOKEY: /* negative key */
664cceb0 427 ret = key_ref;
3e30148c
DH
428 break;
429 default:
664cceb0 430 err = key_ref;
3e30148c
DH
431 break;
432 }
8589b4e0 433 }
b5f545c8 434
927942aa
DH
435 /* no key - decide on the error we're going to go for */
436 key_ref = ret ? ret : err;
437
438found:
439 return key_ref;
440}
441
927942aa 442/*
973c9f4f
DH
443 * Search the process keyrings attached to the supplied cred for the first
444 * matching key in the manner of search_my_process_keyrings(), but also search
445 * the keys attached to the assumed authorisation key using its credentials if
446 * one is available.
447 *
448 * Return same as search_my_process_keyrings().
927942aa 449 */
4bdf0bc3 450key_ref_t search_process_keyrings(struct keyring_search_context *ctx)
927942aa
DH
451{
452 struct request_key_auth *rka;
453 key_ref_t key_ref, ret = ERR_PTR(-EACCES), err;
454
455 might_sleep();
456
4bdf0bc3 457 key_ref = search_my_process_keyrings(ctx);
927942aa
DH
458 if (!IS_ERR(key_ref))
459 goto found;
460 err = key_ref;
461
b5f545c8
DH
462 /* if this process has an instantiation authorisation key, then we also
463 * search the keyrings of the process mentioned there
464 * - we don't permit access to request_key auth keys via this method
465 */
4bdf0bc3
DH
466 if (ctx->cred->request_key_auth &&
467 ctx->cred == current_cred() &&
468 ctx->index_key.type != &key_type_request_key_auth
b5f545c8 469 ) {
4bdf0bc3
DH
470 const struct cred *cred = ctx->cred;
471
04c567d9 472 /* defend against the auth key being revoked */
c69e8d9c 473 down_read(&cred->request_key_auth->sem);
b5f545c8 474
4bdf0bc3 475 if (key_validate(ctx->cred->request_key_auth) == 0) {
146aa8b1 476 rka = ctx->cred->request_key_auth->payload.data[0];
b5f545c8 477
4bdf0bc3
DH
478 ctx->cred = rka->cred;
479 key_ref = search_process_keyrings(ctx);
480 ctx->cred = cred;
1da177e4 481
c69e8d9c 482 up_read(&cred->request_key_auth->sem);
04c567d9
DH
483
484 if (!IS_ERR(key_ref))
485 goto found;
486
927942aa 487 ret = key_ref;
04c567d9 488 } else {
c69e8d9c 489 up_read(&cred->request_key_auth->sem);
3e30148c 490 }
1da177e4
LT
491 }
492
493 /* no key - decide on the error we're going to go for */
927942aa
DH
494 if (err == ERR_PTR(-ENOKEY) || ret == ERR_PTR(-ENOKEY))
495 key_ref = ERR_PTR(-ENOKEY);
496 else if (err == ERR_PTR(-EACCES))
497 key_ref = ret;
498 else
499 key_ref = err;
1da177e4 500
3e30148c 501found:
664cceb0 502 return key_ref;
a8b17ed0 503}
1da177e4 504
664cceb0 505/*
973c9f4f 506 * See if the key we're looking at is the target key.
664cceb0 507 */
0c903ab6
DH
508bool lookup_user_key_possessed(const struct key *key,
509 const struct key_match_data *match_data)
664cceb0 510{
46291959 511 return key == match_data->raw_data;
a8b17ed0 512}
664cceb0 513
1da177e4 514/*
973c9f4f
DH
515 * Look up a key ID given us by userspace with a given permissions mask to get
516 * the key it refers to.
517 *
518 * Flags can be passed to request that special keyrings be created if referred
519 * to directly, to permit partially constructed keys to be found and to skip
520 * validity and permission checks on the found key.
521 *
522 * Returns a pointer to the key with an incremented usage count if successful;
523 * -EINVAL if the key ID is invalid; -ENOKEY if the key ID does not correspond
524 * to a key or the best found key was a negative key; -EKEYREVOKED or
525 * -EKEYEXPIRED if the best found key was revoked or expired; -EACCES if the
526 * found key doesn't grant the requested permit or the LSM denied access to it;
527 * or -ENOMEM if a special keyring couldn't be created.
528 *
529 * In the case of a successful return, the possession attribute is set on the
530 * returned key reference.
1da177e4 531 */
5593122e 532key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
8bbf4976 533 key_perm_t perm)
1da177e4 534{
4bdf0bc3 535 struct keyring_search_context ctx = {
46291959
DH
536 .match_data.cmp = lookup_user_key_possessed,
537 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
538 .flags = KEYRING_SEARCH_NO_STATE_CHECK,
4bdf0bc3 539 };
8bbf4976 540 struct request_key_auth *rka;
1da177e4 541 struct key *key;
b6dff3ec 542 key_ref_t key_ref, skey_ref;
1da177e4
LT
543 int ret;
544
bb952bb9 545try_again:
4bdf0bc3 546 ctx.cred = get_current_cred();
664cceb0 547 key_ref = ERR_PTR(-ENOKEY);
1da177e4
LT
548
549 switch (id) {
550 case KEY_SPEC_THREAD_KEYRING:
4bdf0bc3 551 if (!ctx.cred->thread_keyring) {
5593122e 552 if (!(lflags & KEY_LOOKUP_CREATE))
1da177e4
LT
553 goto error;
554
8bbf4976 555 ret = install_thread_keyring();
1da177e4 556 if (ret < 0) {
4d09ec0f 557 key_ref = ERR_PTR(ret);
1da177e4
LT
558 goto error;
559 }
bb952bb9 560 goto reget_creds;
1da177e4
LT
561 }
562
4bdf0bc3 563 key = ctx.cred->thread_keyring;
ccc3e6d9 564 __key_get(key);
664cceb0 565 key_ref = make_key_ref(key, 1);
1da177e4
LT
566 break;
567
568 case KEY_SPEC_PROCESS_KEYRING:
4bdf0bc3 569 if (!ctx.cred->process_keyring) {
5593122e 570 if (!(lflags & KEY_LOOKUP_CREATE))
1da177e4
LT
571 goto error;
572
8bbf4976 573 ret = install_process_keyring();
1da177e4 574 if (ret < 0) {
4d09ec0f 575 key_ref = ERR_PTR(ret);
1da177e4
LT
576 goto error;
577 }
bb952bb9 578 goto reget_creds;
1da177e4
LT
579 }
580
4bdf0bc3 581 key = ctx.cred->process_keyring;
ccc3e6d9 582 __key_get(key);
664cceb0 583 key_ref = make_key_ref(key, 1);
1da177e4
LT
584 break;
585
586 case KEY_SPEC_SESSION_KEYRING:
4bdf0bc3 587 if (!ctx.cred->session_keyring) {
1da177e4
LT
588 /* always install a session keyring upon access if one
589 * doesn't exist yet */
8bbf4976 590 ret = install_user_keyrings();
69664cf1
DH
591 if (ret < 0)
592 goto error;
3ecf1b4f
DH
593 if (lflags & KEY_LOOKUP_CREATE)
594 ret = join_session_keyring(NULL);
595 else
596 ret = install_session_keyring(
4bdf0bc3 597 ctx.cred->user->session_keyring);
d84f4f99 598
1da177e4
LT
599 if (ret < 0)
600 goto error;
bb952bb9 601 goto reget_creds;
4bdf0bc3
DH
602 } else if (ctx.cred->session_keyring ==
603 ctx.cred->user->session_keyring &&
3ecf1b4f
DH
604 lflags & KEY_LOOKUP_CREATE) {
605 ret = join_session_keyring(NULL);
606 if (ret < 0)
607 goto error;
608 goto reget_creds;
1da177e4
LT
609 }
610
3e30148c 611 rcu_read_lock();
4bdf0bc3 612 key = rcu_dereference(ctx.cred->session_keyring);
ccc3e6d9 613 __key_get(key);
3e30148c 614 rcu_read_unlock();
664cceb0 615 key_ref = make_key_ref(key, 1);
1da177e4
LT
616 break;
617
618 case KEY_SPEC_USER_KEYRING:
4bdf0bc3 619 if (!ctx.cred->user->uid_keyring) {
8bbf4976 620 ret = install_user_keyrings();
69664cf1
DH
621 if (ret < 0)
622 goto error;
623 }
624
4bdf0bc3 625 key = ctx.cred->user->uid_keyring;
ccc3e6d9 626 __key_get(key);
664cceb0 627 key_ref = make_key_ref(key, 1);
1da177e4
LT
628 break;
629
630 case KEY_SPEC_USER_SESSION_KEYRING:
4bdf0bc3 631 if (!ctx.cred->user->session_keyring) {
8bbf4976 632 ret = install_user_keyrings();
69664cf1
DH
633 if (ret < 0)
634 goto error;
635 }
636
4bdf0bc3 637 key = ctx.cred->user->session_keyring;
ccc3e6d9 638 __key_get(key);
664cceb0 639 key_ref = make_key_ref(key, 1);
1da177e4
LT
640 break;
641
642 case KEY_SPEC_GROUP_KEYRING:
643 /* group keyrings are not yet supported */
4d09ec0f 644 key_ref = ERR_PTR(-EINVAL);
1da177e4
LT
645 goto error;
646
b5f545c8 647 case KEY_SPEC_REQKEY_AUTH_KEY:
4bdf0bc3 648 key = ctx.cred->request_key_auth;
b5f545c8
DH
649 if (!key)
650 goto error;
651
ccc3e6d9 652 __key_get(key);
b5f545c8
DH
653 key_ref = make_key_ref(key, 1);
654 break;
655
8bbf4976 656 case KEY_SPEC_REQUESTOR_KEYRING:
4bdf0bc3 657 if (!ctx.cred->request_key_auth)
8bbf4976
DH
658 goto error;
659
4bdf0bc3 660 down_read(&ctx.cred->request_key_auth->sem);
f67dabbd 661 if (test_bit(KEY_FLAG_REVOKED,
4bdf0bc3 662 &ctx.cred->request_key_auth->flags)) {
8bbf4976
DH
663 key_ref = ERR_PTR(-EKEYREVOKED);
664 key = NULL;
665 } else {
146aa8b1 666 rka = ctx.cred->request_key_auth->payload.data[0];
8bbf4976 667 key = rka->dest_keyring;
ccc3e6d9 668 __key_get(key);
8bbf4976 669 }
4bdf0bc3 670 up_read(&ctx.cred->request_key_auth->sem);
8bbf4976
DH
671 if (!key)
672 goto error;
673 key_ref = make_key_ref(key, 1);
674 break;
675
1da177e4 676 default:
664cceb0 677 key_ref = ERR_PTR(-EINVAL);
1da177e4
LT
678 if (id < 1)
679 goto error;
680
681 key = key_lookup(id);
664cceb0 682 if (IS_ERR(key)) {
e231c2ee 683 key_ref = ERR_CAST(key);
1da177e4 684 goto error;
664cceb0
DH
685 }
686
687 key_ref = make_key_ref(key, 0);
688
689 /* check to see if we possess the key */
4bdf0bc3
DH
690 ctx.index_key.type = key->type;
691 ctx.index_key.description = key->description;
692 ctx.index_key.desc_len = strlen(key->description);
46291959 693 ctx.match_data.raw_data = key;
4bdf0bc3
DH
694 kdebug("check possessed");
695 skey_ref = search_process_keyrings(&ctx);
696 kdebug("possessed=%p", skey_ref);
664cceb0
DH
697
698 if (!IS_ERR(skey_ref)) {
699 key_put(key);
700 key_ref = skey_ref;
701 }
702
1da177e4
LT
703 break;
704 }
705
5593122e
DH
706 /* unlink does not use the nominated key in any way, so can skip all
707 * the permission checks as it is only concerned with the keyring */
708 if (lflags & KEY_LOOKUP_FOR_UNLINK) {
709 ret = 0;
710 goto error;
711 }
712
713 if (!(lflags & KEY_LOOKUP_PARTIAL)) {
76181c13
DH
714 ret = wait_for_key_construction(key, true);
715 switch (ret) {
716 case -ERESTARTSYS:
717 goto invalid_key;
718 default:
719 if (perm)
720 goto invalid_key;
721 case 0:
722 break;
723 }
724 } else if (perm) {
1da177e4
LT
725 ret = key_validate(key);
726 if (ret < 0)
727 goto invalid_key;
728 }
729
730 ret = -EIO;
5593122e 731 if (!(lflags & KEY_LOOKUP_PARTIAL) &&
363b02da 732 key_read_state(key) == KEY_IS_UNINSTANTIATED)
1da177e4
LT
733 goto invalid_key;
734
3e30148c 735 /* check the permissions */
4bdf0bc3 736 ret = key_task_permission(key_ref, ctx.cred, perm);
29db9190 737 if (ret < 0)
1da177e4
LT
738 goto invalid_key;
739
074d5898 740 key->last_used_at = ktime_get_real_seconds();
31d5a79d 741
664cceb0 742error:
4bdf0bc3 743 put_cred(ctx.cred);
664cceb0 744 return key_ref;
1da177e4 745
664cceb0
DH
746invalid_key:
747 key_ref_put(key_ref);
748 key_ref = ERR_PTR(ret);
1da177e4
LT
749 goto error;
750
bb952bb9
DH
751 /* if we attempted to install a keyring, then it may have caused new
752 * creds to be installed */
753reget_creds:
4bdf0bc3 754 put_cred(ctx.cred);
bb952bb9 755 goto try_again;
a8b17ed0 756}
76ef5e17 757EXPORT_SYMBOL(lookup_user_key);
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);