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12#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/sched.h>
15#include <linux/sched/user.h>
16#include <linux/keyctl.h>
17#include <linux/fs.h>
18#include <linux/err.h>
19#include <linux/mutex.h>
20#include <linux/security.h>
21#include <linux/user_namespace.h>
22#include <linux/uaccess.h>
23#include "internal.h"
24
25
26static DEFINE_MUTEX(key_session_mutex);
27
28
29static DEFINE_MUTEX(key_user_keyring_mutex);
30
31
32struct key_user root_key_user = {
33 .usage = REFCOUNT_INIT(3),
34 .cons_lock = __MUTEX_INITIALIZER(root_key_user.cons_lock),
35 .lock = __SPIN_LOCK_UNLOCKED(root_key_user.lock),
36 .nkeys = ATOMIC_INIT(2),
37 .nikeys = ATOMIC_INIT(2),
38 .uid = GLOBAL_ROOT_UID,
39};
40
41
42
43
44int install_user_keyrings(void)
45{
46 struct user_struct *user;
47 const struct cred *cred;
48 struct key *uid_keyring, *session_keyring;
49 key_perm_t user_keyring_perm;
50 char buf[20];
51 int ret;
52 uid_t uid;
53
54 user_keyring_perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL;
55 cred = current_cred();
56 user = cred->user;
57 uid = from_kuid(cred->user_ns, user->uid);
58
59 kenter("%p{%u}", user, uid);
60
61 if (user->uid_keyring && user->session_keyring) {
62 kleave(" = 0 [exist]");
63 return 0;
64 }
65
66 mutex_lock(&key_user_keyring_mutex);
67 ret = 0;
68
69 if (!user->uid_keyring) {
70
71
72
73
74 sprintf(buf, "_uid.%u", uid);
75
76 uid_keyring = find_keyring_by_name(buf, true);
77 if (IS_ERR(uid_keyring)) {
78 uid_keyring = keyring_alloc(buf, user->uid, INVALID_GID,
79 cred, user_keyring_perm,
80 KEY_ALLOC_UID_KEYRING |
81 KEY_ALLOC_IN_QUOTA,
82 NULL, NULL);
83 if (IS_ERR(uid_keyring)) {
84 ret = PTR_ERR(uid_keyring);
85 goto error;
86 }
87 }
88
89
90
91 sprintf(buf, "_uid_ses.%u", uid);
92
93 session_keyring = find_keyring_by_name(buf, true);
94 if (IS_ERR(session_keyring)) {
95 session_keyring =
96 keyring_alloc(buf, user->uid, INVALID_GID,
97 cred, user_keyring_perm,
98 KEY_ALLOC_UID_KEYRING |
99 KEY_ALLOC_IN_QUOTA,
100 NULL, NULL);
101 if (IS_ERR(session_keyring)) {
102 ret = PTR_ERR(session_keyring);
103 goto error_release;
104 }
105
106
107
108 ret = key_link(session_keyring, uid_keyring);
109 if (ret < 0)
110 goto error_release_both;
111 }
112
113
114 user->uid_keyring = uid_keyring;
115 user->session_keyring = session_keyring;
116 }
117
118 mutex_unlock(&key_user_keyring_mutex);
119 kleave(" = 0");
120 return 0;
121
122error_release_both:
123 key_put(session_keyring);
124error_release:
125 key_put(uid_keyring);
126error:
127 mutex_unlock(&key_user_keyring_mutex);
128 kleave(" = %d", ret);
129 return ret;
130}
131
132
133
134
135
136
137
138int install_thread_keyring_to_cred(struct cred *new)
139{
140 struct key *keyring;
141
142 if (new->thread_keyring)
143 return 0;
144
145 keyring = keyring_alloc("_tid", new->uid, new->gid, new,
146 KEY_POS_ALL | KEY_USR_VIEW,
147 KEY_ALLOC_QUOTA_OVERRUN,
148 NULL, NULL);
149 if (IS_ERR(keyring))
150 return PTR_ERR(keyring);
151
152 new->thread_keyring = keyring;
153 return 0;
154}
155
156
157
158
159
160
161static int install_thread_keyring(void)
162{
163 struct cred *new;
164 int ret;
165
166 new = prepare_creds();
167 if (!new)
168 return -ENOMEM;
169
170 ret = install_thread_keyring_to_cred(new);
171 if (ret < 0) {
172 abort_creds(new);
173 return ret;
174 }
175
176 return commit_creds(new);
177}
178
179
180
181
182
183
184
185int install_process_keyring_to_cred(struct cred *new)
186{
187 struct key *keyring;
188
189 if (new->process_keyring)
190 return 0;
191
192 keyring = keyring_alloc("_pid", new->uid, new->gid, new,
193 KEY_POS_ALL | KEY_USR_VIEW,
194 KEY_ALLOC_QUOTA_OVERRUN,
195 NULL, NULL);
196 if (IS_ERR(keyring))
197 return PTR_ERR(keyring);
198
199 new->process_keyring = keyring;
200 return 0;
201}
202
203
204
205
206
207
208static int install_process_keyring(void)
209{
210 struct cred *new;
211 int ret;
212
213 new = prepare_creds();
214 if (!new)
215 return -ENOMEM;
216
217 ret = install_process_keyring_to_cred(new);
218 if (ret < 0) {
219 abort_creds(new);
220 return ret;
221 }
222
223 return commit_creds(new);
224}
225
226
227
228
229
230
231
232
233int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
234{
235 unsigned long flags;
236 struct key *old;
237
238 might_sleep();
239
240
241 if (!keyring) {
242 flags = KEY_ALLOC_QUOTA_OVERRUN;
243 if (cred->session_keyring)
244 flags = KEY_ALLOC_IN_QUOTA;
245
246 keyring = keyring_alloc("_ses", cred->uid, cred->gid, cred,
247 KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ,
248 flags, NULL, NULL);
249 if (IS_ERR(keyring))
250 return PTR_ERR(keyring);
251 } else {
252 __key_get(keyring);
253 }
254
255
256 old = cred->session_keyring;
257 rcu_assign_pointer(cred->session_keyring, keyring);
258
259 if (old)
260 key_put(old);
261
262 return 0;
263}
264
265
266
267
268
269
270
271
272static int install_session_keyring(struct key *keyring)
273{
274 struct cred *new;
275 int ret;
276
277 new = prepare_creds();
278 if (!new)
279 return -ENOMEM;
280
281 ret = install_session_keyring_to_cred(new, keyring);
282 if (ret < 0) {
283 abort_creds(new);
284 return ret;
285 }
286
287 return commit_creds(new);
288}
289
290
291
292
293void key_fsuid_changed(struct task_struct *tsk)
294{
295
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);
301 }
302}
303
304
305
306
307void key_fsgid_changed(struct task_struct *tsk)
308{
309
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);
315 }
316}
317
318
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321
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324
325
326
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331
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333
334
335
336
337
338
339key_ref_t search_my_process_keyrings(struct keyring_search_context *ctx)
340{
341 key_ref_t key_ref, ret, err;
342
343
344
345
346
347
348
349
350 key_ref = NULL;
351 ret = NULL;
352 err = ERR_PTR(-EAGAIN);
353
354
355 if (ctx->cred->thread_keyring) {
356 key_ref = keyring_search_aux(
357 make_key_ref(ctx->cred->thread_keyring, 1), ctx);
358 if (!IS_ERR(key_ref))
359 goto found;
360
361 switch (PTR_ERR(key_ref)) {
362 case -EAGAIN:
363 case -ENOKEY:
364 ret = key_ref;
365 break;
366 default:
367 err = key_ref;
368 break;
369 }
370 }
371
372
373 if (ctx->cred->process_keyring) {
374 key_ref = keyring_search_aux(
375 make_key_ref(ctx->cred->process_keyring, 1), ctx);
376 if (!IS_ERR(key_ref))
377 goto found;
378
379 switch (PTR_ERR(key_ref)) {
380 case -EAGAIN:
381 if (ret)
382 break;
383 case -ENOKEY:
384 ret = key_ref;
385 break;
386 default:
387 err = key_ref;
388 break;
389 }
390 }
391
392
393 if (ctx->cred->session_keyring) {
394 rcu_read_lock();
395 key_ref = keyring_search_aux(
396 make_key_ref(rcu_dereference(ctx->cred->session_keyring), 1),
397 ctx);
398 rcu_read_unlock();
399
400 if (!IS_ERR(key_ref))
401 goto found;
402
403 switch (PTR_ERR(key_ref)) {
404 case -EAGAIN:
405 if (ret)
406 break;
407 case -ENOKEY:
408 ret = key_ref;
409 break;
410 default:
411 err = key_ref;
412 break;
413 }
414 }
415
416 else if (ctx->cred->user->session_keyring) {
417 key_ref = keyring_search_aux(
418 make_key_ref(ctx->cred->user->session_keyring, 1),
419 ctx);
420 if (!IS_ERR(key_ref))
421 goto found;
422
423 switch (PTR_ERR(key_ref)) {
424 case -EAGAIN:
425 if (ret)
426 break;
427 case -ENOKEY:
428 ret = key_ref;
429 break;
430 default:
431 err = key_ref;
432 break;
433 }
434 }
435
436
437 key_ref = ret ? ret : err;
438
439found:
440 return key_ref;
441}
442
443
444
445
446
447
448
449
450
451key_ref_t search_process_keyrings(struct keyring_search_context *ctx)
452{
453 struct request_key_auth *rka;
454 key_ref_t key_ref, ret = ERR_PTR(-EACCES), err;
455
456 might_sleep();
457
458 key_ref = search_my_process_keyrings(ctx);
459 if (!IS_ERR(key_ref))
460 goto found;
461 err = key_ref;
462
463
464
465
466
467 if (ctx->cred->request_key_auth &&
468 ctx->cred == current_cred() &&
469 ctx->index_key.type != &key_type_request_key_auth
470 ) {
471 const struct cred *cred = ctx->cred;
472
473
474 down_read(&cred->request_key_auth->sem);
475
476 if (key_validate(ctx->cred->request_key_auth) == 0) {
477 rka = ctx->cred->request_key_auth->payload.data[0];
478
479 ctx->cred = rka->cred;
480 key_ref = search_process_keyrings(ctx);
481 ctx->cred = cred;
482
483 up_read(&cred->request_key_auth->sem);
484
485 if (!IS_ERR(key_ref))
486 goto found;
487
488 ret = key_ref;
489 } else {
490 up_read(&cred->request_key_auth->sem);
491 }
492 }
493
494
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;
501
502found:
503 return key_ref;
504}
505
506
507
508
509bool lookup_user_key_possessed(const struct key *key,
510 const struct key_match_data *match_data)
511{
512 return key == match_data->raw_data;
513}
514
515
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525
526
527
528
529
530
531
532
533key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
534 key_perm_t perm)
535{
536 struct keyring_search_context ctx = {
537 .match_data.cmp = lookup_user_key_possessed,
538 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
539 .flags = KEYRING_SEARCH_NO_STATE_CHECK,
540 };
541 struct request_key_auth *rka;
542 struct key *key;
543 key_ref_t key_ref, skey_ref;
544 int ret;
545
546try_again:
547 ctx.cred = get_current_cred();
548 key_ref = ERR_PTR(-ENOKEY);
549
550 switch (id) {
551 case KEY_SPEC_THREAD_KEYRING:
552 if (!ctx.cred->thread_keyring) {
553 if (!(lflags & KEY_LOOKUP_CREATE))
554 goto error;
555
556 ret = install_thread_keyring();
557 if (ret < 0) {
558 key_ref = ERR_PTR(ret);
559 goto error;
560 }
561 goto reget_creds;
562 }
563
564 key = ctx.cred->thread_keyring;
565 __key_get(key);
566 key_ref = make_key_ref(key, 1);
567 break;
568
569 case KEY_SPEC_PROCESS_KEYRING:
570 if (!ctx.cred->process_keyring) {
571 if (!(lflags & KEY_LOOKUP_CREATE))
572 goto error;
573
574 ret = install_process_keyring();
575 if (ret < 0) {
576 key_ref = ERR_PTR(ret);
577 goto error;
578 }
579 goto reget_creds;
580 }
581
582 key = ctx.cred->process_keyring;
583 __key_get(key);
584 key_ref = make_key_ref(key, 1);
585 break;
586
587 case KEY_SPEC_SESSION_KEYRING:
588 if (!ctx.cred->session_keyring) {
589
590
591 ret = install_user_keyrings();
592 if (ret < 0)
593 goto error;
594 if (lflags & KEY_LOOKUP_CREATE)
595 ret = join_session_keyring(NULL);
596 else
597 ret = install_session_keyring(
598 ctx.cred->user->session_keyring);
599
600 if (ret < 0)
601 goto error;
602 goto reget_creds;
603 } else if (ctx.cred->session_keyring ==
604 ctx.cred->user->session_keyring &&
605 lflags & KEY_LOOKUP_CREATE) {
606 ret = join_session_keyring(NULL);
607 if (ret < 0)
608 goto error;
609 goto reget_creds;
610 }
611
612 rcu_read_lock();
613 key = rcu_dereference(ctx.cred->session_keyring);
614 __key_get(key);
615 rcu_read_unlock();
616 key_ref = make_key_ref(key, 1);
617 break;
618
619 case KEY_SPEC_USER_KEYRING:
620 if (!ctx.cred->user->uid_keyring) {
621 ret = install_user_keyrings();
622 if (ret < 0)
623 goto error;
624 }
625
626 key = ctx.cred->user->uid_keyring;
627 __key_get(key);
628 key_ref = make_key_ref(key, 1);
629 break;
630
631 case KEY_SPEC_USER_SESSION_KEYRING:
632 if (!ctx.cred->user->session_keyring) {
633 ret = install_user_keyrings();
634 if (ret < 0)
635 goto error;
636 }
637
638 key = ctx.cred->user->session_keyring;
639 __key_get(key);
640 key_ref = make_key_ref(key, 1);
641 break;
642
643 case KEY_SPEC_GROUP_KEYRING:
644
645 key_ref = ERR_PTR(-EINVAL);
646 goto error;
647
648 case KEY_SPEC_REQKEY_AUTH_KEY:
649 key = ctx.cred->request_key_auth;
650 if (!key)
651 goto error;
652
653 __key_get(key);
654 key_ref = make_key_ref(key, 1);
655 break;
656
657 case KEY_SPEC_REQUESTOR_KEYRING:
658 if (!ctx.cred->request_key_auth)
659 goto error;
660
661 down_read(&ctx.cred->request_key_auth->sem);
662 if (test_bit(KEY_FLAG_REVOKED,
663 &ctx.cred->request_key_auth->flags)) {
664 key_ref = ERR_PTR(-EKEYREVOKED);
665 key = NULL;
666 } else {
667 rka = ctx.cred->request_key_auth->payload.data[0];
668 key = rka->dest_keyring;
669 __key_get(key);
670 }
671 up_read(&ctx.cred->request_key_auth->sem);
672 if (!key)
673 goto error;
674 key_ref = make_key_ref(key, 1);
675 break;
676
677 default:
678 key_ref = ERR_PTR(-EINVAL);
679 if (id < 1)
680 goto error;
681
682 key = key_lookup(id);
683 if (IS_ERR(key)) {
684 key_ref = ERR_CAST(key);
685 goto error;
686 }
687
688 key_ref = make_key_ref(key, 0);
689
690
691 ctx.index_key.type = key->type;
692 ctx.index_key.description = key->description;
693 ctx.index_key.desc_len = strlen(key->description);
694 ctx.match_data.raw_data = key;
695 kdebug("check possessed");
696 skey_ref = search_process_keyrings(&ctx);
697 kdebug("possessed=%p", skey_ref);
698
699 if (!IS_ERR(skey_ref)) {
700 key_put(key);
701 key_ref = skey_ref;
702 }
703
704 break;
705 }
706
707
708
709 if (lflags & KEY_LOOKUP_FOR_UNLINK) {
710 ret = 0;
711 goto error;
712 }
713
714 if (!(lflags & KEY_LOOKUP_PARTIAL)) {
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) {
726 ret = key_validate(key);
727 if (ret < 0)
728 goto invalid_key;
729 }
730
731 ret = -EIO;
732 if (!(lflags & KEY_LOOKUP_PARTIAL) &&
733 key_read_state(key) == KEY_IS_UNINSTANTIATED)
734 goto invalid_key;
735
736
737 ret = key_task_permission(key_ref, ctx.cred, perm);
738 if (ret < 0)
739 goto invalid_key;
740
741 key->last_used_at = ktime_get_real_seconds();
742
743error:
744 put_cred(ctx.cred);
745 return key_ref;
746
747invalid_key:
748 key_ref_put(key_ref);
749 key_ref = ERR_PTR(ret);
750 goto error;
751
752
753
754reget_creds:
755 put_cred(ctx.cred);
756 goto try_again;
757}
758
759
760
761
762
763
764
765
766
767
768
769
770long join_session_keyring(const char *name)
771{
772 const struct cred *old;
773 struct cred *new;
774 struct key *keyring;
775 long ret, serial;
776
777 new = prepare_creds();
778 if (!new)
779 return -ENOMEM;
780 old = current_cred();
781
782
783 if (!name) {
784 ret = install_session_keyring_to_cred(new, NULL);
785 if (ret < 0)
786 goto error;
787
788 serial = new->session_keyring->serial;
789 ret = commit_creds(new);
790 if (ret == 0)
791 ret = serial;
792 goto okay;
793 }
794
795
796 mutex_lock(&key_session_mutex);
797
798
799 keyring = find_keyring_by_name(name, false);
800 if (PTR_ERR(keyring) == -ENOKEY) {
801
802 keyring = keyring_alloc(
803 name, old->uid, old->gid, old,
804 KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_LINK,
805 KEY_ALLOC_IN_QUOTA, NULL, NULL);
806 if (IS_ERR(keyring)) {
807 ret = PTR_ERR(keyring);
808 goto error2;
809 }
810 } else if (IS_ERR(keyring)) {
811 ret = PTR_ERR(keyring);
812 goto error2;
813 } else if (keyring == new->session_keyring) {
814 ret = 0;
815 goto error3;
816 }
817
818
819 ret = install_session_keyring_to_cred(new, keyring);
820 if (ret < 0)
821 goto error3;
822
823 commit_creds(new);
824 mutex_unlock(&key_session_mutex);
825
826 ret = keyring->serial;
827 key_put(keyring);
828okay:
829 return ret;
830
831error3:
832 key_put(keyring);
833error2:
834 mutex_unlock(&key_session_mutex);
835error:
836 abort_creds(new);
837 return ret;
838}
839
840
841
842
843
844void key_change_session_keyring(struct callback_head *twork)
845{
846 const struct cred *old = current_cred();
847 struct cred *new = container_of(twork, struct cred, rcu);
848
849 if (unlikely(current->flags & PF_EXITING)) {
850 put_cred(new);
851 return;
852 }
853
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);
863 new->user_ns = get_user_ns(old->user_ns);
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;
870 new->cap_ambient = old->cap_ambient;
871 new->cap_bset = old->cap_bset;
872
873 new->jit_keyring = old->jit_keyring;
874 new->thread_keyring = key_get(old->thread_keyring);
875 new->process_keyring = key_get(old->process_keyring);
876
877 security_transfer_creds(new, old);
878
879 commit_creds(new);
880}
881
882
883
884
885static int __init init_root_keyring(void)
886{
887 return install_user_keyrings();
888}
889
890late_initcall(init_root_keyring);
891