Root/security/keys/process_keys.c

Source at commit be977234bfb4a6dca8a39e7c52165e4cd536ad71 created 9 years 5 months ago.
By Lars-Peter Clausen, jz4740: Fix compile error
1/* Manage a process's keyrings
2 *
3 * Copyright (C) 2004-2005, 2008 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/sched.h>
15#include <linux/keyctl.h>
16#include <linux/fs.h>
17#include <linux/err.h>
18#include <linux/mutex.h>
19#include <linux/security.h>
20#include <linux/user_namespace.h>
21#include <asm/uaccess.h>
22#include "internal.h"
23
24/* Session keyring create vs join semaphore */
25static DEFINE_MUTEX(key_session_mutex);
26
27/* User keyring creation semaphore */
28static DEFINE_MUTEX(key_user_keyring_mutex);
29
30/* The root user's tracking struct */
31struct key_user root_key_user = {
32    .usage = ATOMIC_INIT(3),
33    .cons_lock = __MUTEX_INITIALIZER(root_key_user.cons_lock),
34    .lock = __SPIN_LOCK_UNLOCKED(root_key_user.lock),
35    .nkeys = ATOMIC_INIT(2),
36    .nikeys = ATOMIC_INIT(2),
37    .uid = 0,
38    .user_ns = &init_user_ns,
39};
40
41/*
42 * Install the user and user session keyrings for the current process's UID.
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    char buf[20];
50    int ret;
51
52    cred = current_cred();
53    user = cred->user;
54
55    kenter("%p{%u}", user, user->uid);
56
57    if (user->uid_keyring) {
58        kleave(" = 0 [exist]");
59        return 0;
60    }
61
62    mutex_lock(&key_user_keyring_mutex);
63    ret = 0;
64
65    if (!user->uid_keyring) {
66        /* get the UID-specific keyring
67         * - there may be one in existence already as it may have been
68         * pinned by a session, but the user_struct pointing to it
69         * may have been destroyed by setuid */
70        sprintf(buf, "_uid.%u", user->uid);
71
72        uid_keyring = find_keyring_by_name(buf, true);
73        if (IS_ERR(uid_keyring)) {
74            uid_keyring = keyring_alloc(buf, user->uid, (gid_t) -1,
75                            cred, KEY_ALLOC_IN_QUOTA,
76                            NULL);
77            if (IS_ERR(uid_keyring)) {
78                ret = PTR_ERR(uid_keyring);
79                goto error;
80            }
81        }
82
83        /* get a default session keyring (which might also exist
84         * already) */
85        sprintf(buf, "_uid_ses.%u", user->uid);
86
87        session_keyring = find_keyring_by_name(buf, true);
88        if (IS_ERR(session_keyring)) {
89            session_keyring =
90                keyring_alloc(buf, user->uid, (gid_t) -1,
91                          cred, KEY_ALLOC_IN_QUOTA, NULL);
92            if (IS_ERR(session_keyring)) {
93                ret = PTR_ERR(session_keyring);
94                goto error_release;
95            }
96
97            /* we install a link from the user session keyring to
98             * the user keyring */
99            ret = key_link(session_keyring, uid_keyring);
100            if (ret < 0)
101                goto error_release_both;
102        }
103
104        /* install the keyrings */
105        user->uid_keyring = uid_keyring;
106        user->session_keyring = session_keyring;
107    }
108
109    mutex_unlock(&key_user_keyring_mutex);
110    kleave(" = 0");
111    return 0;
112
113error_release_both:
114    key_put(session_keyring);
115error_release:
116    key_put(uid_keyring);
117error:
118    mutex_unlock(&key_user_keyring_mutex);
119    kleave(" = %d", ret);
120    return ret;
121}
122
123/*
124 * Install a fresh thread keyring directly to new credentials. This keyring is
125 * allowed to overrun the quota.
126 */
127int install_thread_keyring_to_cred(struct cred *new)
128{
129    struct key *keyring;
130
131    keyring = keyring_alloc("_tid", new->uid, new->gid, new,
132                KEY_ALLOC_QUOTA_OVERRUN, NULL);
133    if (IS_ERR(keyring))
134        return PTR_ERR(keyring);
135
136    new->thread_keyring = keyring;
137    return 0;
138}
139
140/*
141 * Install a fresh thread keyring, discarding the old one.
142 */
143static int install_thread_keyring(void)
144{
145    struct cred *new;
146    int ret;
147
148    new = prepare_creds();
149    if (!new)
150        return -ENOMEM;
151
152    BUG_ON(new->thread_keyring);
153
154    ret = install_thread_keyring_to_cred(new);
155    if (ret < 0) {
156        abort_creds(new);
157        return ret;
158    }
159
160    return commit_creds(new);
161}
162
163/*
164 * Install a process keyring directly to a credentials struct.
165 *
166 * Returns -EEXIST if there was already a process keyring, 0 if one installed,
167 * and other value on any other error
168 */
169int install_process_keyring_to_cred(struct cred *new)
170{
171    struct key *keyring;
172    int ret;
173
174    if (new->tgcred->process_keyring)
175        return -EEXIST;
176
177    keyring = keyring_alloc("_pid", new->uid, new->gid,
178                new, KEY_ALLOC_QUOTA_OVERRUN, NULL);
179    if (IS_ERR(keyring))
180        return PTR_ERR(keyring);
181
182    spin_lock_irq(&new->tgcred->lock);
183    if (!new->tgcred->process_keyring) {
184        new->tgcred->process_keyring = keyring;
185        keyring = NULL;
186        ret = 0;
187    } else {
188        ret = -EEXIST;
189    }
190    spin_unlock_irq(&new->tgcred->lock);
191    key_put(keyring);
192    return ret;
193}
194
195/*
196 * Make sure a process keyring is installed for the current process. The
197 * existing process keyring is not replaced.
198 *
199 * Returns 0 if there is a process keyring by the end of this function, some
200 * error otherwise.
201 */
202static int install_process_keyring(void)
203{
204    struct cred *new;
205    int ret;
206
207    new = prepare_creds();
208    if (!new)
209        return -ENOMEM;
210
211    ret = install_process_keyring_to_cred(new);
212    if (ret < 0) {
213        abort_creds(new);
214        return ret != -EEXIST ? ret : 0;
215    }
216
217    return commit_creds(new);
218}
219
220/*
221 * Install a session keyring directly to a credentials struct.
222 */
223int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
224{
225    unsigned long flags;
226    struct key *old;
227
228    might_sleep();
229
230    /* create an empty session keyring */
231    if (!keyring) {
232        flags = KEY_ALLOC_QUOTA_OVERRUN;
233        if (cred->tgcred->session_keyring)
234            flags = KEY_ALLOC_IN_QUOTA;
235
236        keyring = keyring_alloc("_ses", cred->uid, cred->gid,
237                    cred, flags, NULL);
238        if (IS_ERR(keyring))
239            return PTR_ERR(keyring);
240    } else {
241        atomic_inc(&keyring->usage);
242    }
243
244    /* install the keyring */
245    spin_lock_irq(&cred->tgcred->lock);
246    old = cred->tgcred->session_keyring;
247    rcu_assign_pointer(cred->tgcred->session_keyring, keyring);
248    spin_unlock_irq(&cred->tgcred->lock);
249
250    /* we're using RCU on the pointer, but there's no point synchronising
251     * on it if it didn't previously point to anything */
252    if (old) {
253        synchronize_rcu();
254        key_put(old);
255    }
256
257    return 0;
258}
259
260/*
261 * Install a session keyring, discarding the old one. If a keyring is not
262 * supplied, an empty one is invented.
263 */
264static int install_session_keyring(struct key *keyring)
265{
266    struct cred *new;
267    int ret;
268
269    new = prepare_creds();
270    if (!new)
271        return -ENOMEM;
272
273    ret = install_session_keyring_to_cred(new, NULL);
274    if (ret < 0) {
275        abort_creds(new);
276        return ret;
277    }
278
279    return commit_creds(new);
280}
281
282/*
283 * Handle the fsuid changing.
284 */
285void key_fsuid_changed(struct task_struct *tsk)
286{
287    /* update the ownership of the thread keyring */
288    BUG_ON(!tsk->cred);
289    if (tsk->cred->thread_keyring) {
290        down_write(&tsk->cred->thread_keyring->sem);
291        tsk->cred->thread_keyring->uid = tsk->cred->fsuid;
292        up_write(&tsk->cred->thread_keyring->sem);
293    }
294}
295
296/*
297 * Handle the fsgid changing.
298 */
299void key_fsgid_changed(struct task_struct *tsk)
300{
301    /* update the ownership of the thread keyring */
302    BUG_ON(!tsk->cred);
303    if (tsk->cred->thread_keyring) {
304        down_write(&tsk->cred->thread_keyring->sem);
305        tsk->cred->thread_keyring->gid = tsk->cred->fsgid;
306        up_write(&tsk->cred->thread_keyring->sem);
307    }
308}
309
310/*
311 * Search the process keyrings attached to the supplied cred for the first
312 * matching key.
313 *
314 * The search criteria are the type and the match function. The description is
315 * given to the match function as a parameter, but doesn't otherwise influence
316 * the search. Typically the match function will compare the description
317 * parameter to the key's description.
318 *
319 * This can only search keyrings that grant Search permission to the supplied
320 * credentials. Keyrings linked to searched keyrings will also be searched if
321 * they grant Search permission too. Keys can only be found if they grant
322 * Search permission to the credentials.
323 *
324 * Returns a pointer to the key with the key usage count incremented if
325 * successful, -EAGAIN if we didn't find any matching key or -ENOKEY if we only
326 * matched negative keys.
327 *
328 * In the case of a successful return, the possession attribute is set on the
329 * returned key reference.
330 */
331key_ref_t search_my_process_keyrings(struct key_type *type,
332                     const void *description,
333                     key_match_func_t match,
334                     const struct cred *cred)
335{
336    key_ref_t key_ref, ret, err;
337
338    /* we want to return -EAGAIN or -ENOKEY if any of the keyrings were
339     * searchable, but we failed to find a key or we found a negative key;
340     * otherwise we want to return a sample error (probably -EACCES) if
341     * none of the keyrings were searchable
342     *
343     * in terms of priority: success > -ENOKEY > -EAGAIN > other error
344     */
345    key_ref = NULL;
346    ret = NULL;
347    err = ERR_PTR(-EAGAIN);
348
349    /* search the thread keyring first */
350    if (cred->thread_keyring) {
351        key_ref = keyring_search_aux(
352            make_key_ref(cred->thread_keyring, 1),
353            cred, type, description, match);
354        if (!IS_ERR(key_ref))
355            goto found;
356
357        switch (PTR_ERR(key_ref)) {
358        case -EAGAIN: /* no key */
359            if (ret)
360                break;
361        case -ENOKEY: /* negative key */
362            ret = key_ref;
363            break;
364        default:
365            err = key_ref;
366            break;
367        }
368    }
369
370    /* search the process keyring second */
371    if (cred->tgcred->process_keyring) {
372        key_ref = keyring_search_aux(
373            make_key_ref(cred->tgcred->process_keyring, 1),
374            cred, type, description, match);
375        if (!IS_ERR(key_ref))
376            goto found;
377
378        switch (PTR_ERR(key_ref)) {
379        case -EAGAIN: /* no key */
380            if (ret)
381                break;
382        case -ENOKEY: /* negative key */
383            ret = key_ref;
384            break;
385        default:
386            err = key_ref;
387            break;
388        }
389    }
390
391    /* search the session keyring */
392    if (cred->tgcred->session_keyring) {
393        rcu_read_lock();
394        key_ref = keyring_search_aux(
395            make_key_ref(rcu_dereference(
396                         cred->tgcred->session_keyring),
397                     1),
398            cred, type, description, match);
399        rcu_read_unlock();
400
401        if (!IS_ERR(key_ref))
402            goto found;
403
404        switch (PTR_ERR(key_ref)) {
405        case -EAGAIN: /* no key */
406            if (ret)
407                break;
408        case -ENOKEY: /* negative key */
409            ret = key_ref;
410            break;
411        default:
412            err = key_ref;
413            break;
414        }
415    }
416    /* or search the user-session keyring */
417    else if (cred->user->session_keyring) {
418        key_ref = keyring_search_aux(
419            make_key_ref(cred->user->session_keyring, 1),
420            cred, type, description, match);
421        if (!IS_ERR(key_ref))
422            goto found;
423
424        switch (PTR_ERR(key_ref)) {
425        case -EAGAIN: /* no key */
426            if (ret)
427                break;
428        case -ENOKEY: /* negative key */
429            ret = key_ref;
430            break;
431        default:
432            err = key_ref;
433            break;
434        }
435    }
436
437    /* no key - decide on the error we're going to go for */
438    key_ref = ret ? ret : err;
439
440found:
441    return key_ref;
442}
443
444/*
445 * Search the process keyrings attached to the supplied cred for the first
446 * matching key in the manner of search_my_process_keyrings(), but also search
447 * the keys attached to the assumed authorisation key using its credentials if
448 * one is available.
449 *
450 * Return same as search_my_process_keyrings().
451 */
452key_ref_t search_process_keyrings(struct key_type *type,
453                  const void *description,
454                  key_match_func_t match,
455                  const struct cred *cred)
456{
457    struct request_key_auth *rka;
458    key_ref_t key_ref, ret = ERR_PTR(-EACCES), err;
459
460    might_sleep();
461
462    key_ref = search_my_process_keyrings(type, description, match, cred);
463    if (!IS_ERR(key_ref))
464        goto found;
465    err = key_ref;
466
467    /* if this process has an instantiation authorisation key, then we also
468     * search the keyrings of the process mentioned there
469     * - we don't permit access to request_key auth keys via this method
470     */
471    if (cred->request_key_auth &&
472        cred == current_cred() &&
473        type != &key_type_request_key_auth
474        ) {
475        /* defend against the auth key being revoked */
476        down_read(&cred->request_key_auth->sem);
477
478        if (key_validate(cred->request_key_auth) == 0) {
479            rka = cred->request_key_auth->payload.data;
480
481            key_ref = search_process_keyrings(type, description,
482                              match, rka->cred);
483
484            up_read(&cred->request_key_auth->sem);
485
486            if (!IS_ERR(key_ref))
487                goto found;
488
489            ret = key_ref;
490        } else {
491            up_read(&cred->request_key_auth->sem);
492        }
493    }
494
495    /* no key - decide on the error we're going to go for */
496    if (err == ERR_PTR(-ENOKEY) || ret == ERR_PTR(-ENOKEY))
497        key_ref = ERR_PTR(-ENOKEY);
498    else if (err == ERR_PTR(-EACCES))
499        key_ref = ret;
500    else
501        key_ref = err;
502
503found:
504    return key_ref;
505}
506
507/*
508 * See if the key we're looking at is the target key.
509 */
510int lookup_user_key_possessed(const struct key *key, const void *target)
511{
512    return key == target;
513}
514
515/*
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.
532 */
533key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
534              key_perm_t perm)
535{
536    struct request_key_auth *rka;
537    const struct cred *cred;
538    struct key *key;
539    key_ref_t key_ref, skey_ref;
540    int ret;
541
542try_again:
543    cred = get_current_cred();
544    key_ref = ERR_PTR(-ENOKEY);
545
546    switch (id) {
547    case KEY_SPEC_THREAD_KEYRING:
548        if (!cred->thread_keyring) {
549            if (!(lflags & KEY_LOOKUP_CREATE))
550                goto error;
551
552            ret = install_thread_keyring();
553            if (ret < 0) {
554                key_ref = ERR_PTR(ret);
555                goto error;
556            }
557            goto reget_creds;
558        }
559
560        key = cred->thread_keyring;
561        atomic_inc(&key->usage);
562        key_ref = make_key_ref(key, 1);
563        break;
564
565    case KEY_SPEC_PROCESS_KEYRING:
566        if (!cred->tgcred->process_keyring) {
567            if (!(lflags & KEY_LOOKUP_CREATE))
568                goto error;
569
570            ret = install_process_keyring();
571            if (ret < 0) {
572                key_ref = ERR_PTR(ret);
573                goto error;
574            }
575            goto reget_creds;
576        }
577
578        key = cred->tgcred->process_keyring;
579        atomic_inc(&key->usage);
580        key_ref = make_key_ref(key, 1);
581        break;
582
583    case KEY_SPEC_SESSION_KEYRING:
584        if (!cred->tgcred->session_keyring) {
585            /* always install a session keyring upon access if one
586             * doesn't exist yet */
587            ret = install_user_keyrings();
588            if (ret < 0)
589                goto error;
590            ret = install_session_keyring(
591                cred->user->session_keyring);
592
593            if (ret < 0)
594                goto error;
595            goto reget_creds;
596        }
597
598        rcu_read_lock();
599        key = rcu_dereference(cred->tgcred->session_keyring);
600        atomic_inc(&key->usage);
601        rcu_read_unlock();
602        key_ref = make_key_ref(key, 1);
603        break;
604
605    case KEY_SPEC_USER_KEYRING:
606        if (!cred->user->uid_keyring) {
607            ret = install_user_keyrings();
608            if (ret < 0)
609                goto error;
610        }
611
612        key = cred->user->uid_keyring;
613        atomic_inc(&key->usage);
614        key_ref = make_key_ref(key, 1);
615        break;
616
617    case KEY_SPEC_USER_SESSION_KEYRING:
618        if (!cred->user->session_keyring) {
619            ret = install_user_keyrings();
620            if (ret < 0)
621                goto error;
622        }
623
624        key = cred->user->session_keyring;
625        atomic_inc(&key->usage);
626        key_ref = make_key_ref(key, 1);
627        break;
628
629    case KEY_SPEC_GROUP_KEYRING:
630        /* group keyrings are not yet supported */
631        key_ref = ERR_PTR(-EINVAL);
632        goto error;
633
634    case KEY_SPEC_REQKEY_AUTH_KEY:
635        key = cred->request_key_auth;
636        if (!key)
637            goto error;
638
639        atomic_inc(&key->usage);
640        key_ref = make_key_ref(key, 1);
641        break;
642
643    case KEY_SPEC_REQUESTOR_KEYRING:
644        if (!cred->request_key_auth)
645            goto error;
646
647        down_read(&cred->request_key_auth->sem);
648        if (cred->request_key_auth->flags & KEY_FLAG_REVOKED) {
649            key_ref = ERR_PTR(-EKEYREVOKED);
650            key = NULL;
651        } else {
652            rka = cred->request_key_auth->payload.data;
653            key = rka->dest_keyring;
654            atomic_inc(&key->usage);
655        }
656        up_read(&cred->request_key_auth->sem);
657        if (!key)
658            goto error;
659        key_ref = make_key_ref(key, 1);
660        break;
661
662    default:
663        key_ref = ERR_PTR(-EINVAL);
664        if (id < 1)
665            goto error;
666
667        key = key_lookup(id);
668        if (IS_ERR(key)) {
669            key_ref = ERR_CAST(key);
670            goto error;
671        }
672
673        key_ref = make_key_ref(key, 0);
674
675        /* check to see if we possess the key */
676        skey_ref = search_process_keyrings(key->type, key,
677                           lookup_user_key_possessed,
678                           cred);
679
680        if (!IS_ERR(skey_ref)) {
681            key_put(key);
682            key_ref = skey_ref;
683        }
684
685        break;
686    }
687
688    /* unlink does not use the nominated key in any way, so can skip all
689     * the permission checks as it is only concerned with the keyring */
690    if (lflags & KEY_LOOKUP_FOR_UNLINK) {
691        ret = 0;
692        goto error;
693    }
694
695    if (!(lflags & KEY_LOOKUP_PARTIAL)) {
696        ret = wait_for_key_construction(key, true);
697        switch (ret) {
698        case -ERESTARTSYS:
699            goto invalid_key;
700        default:
701            if (perm)
702                goto invalid_key;
703        case 0:
704            break;
705        }
706    } else if (perm) {
707        ret = key_validate(key);
708        if (ret < 0)
709            goto invalid_key;
710    }
711
712    ret = -EIO;
713    if (!(lflags & KEY_LOOKUP_PARTIAL) &&
714        !test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
715        goto invalid_key;
716
717    /* check the permissions */
718    ret = key_task_permission(key_ref, cred, perm);
719    if (ret < 0)
720        goto invalid_key;
721
722error:
723    put_cred(cred);
724    return key_ref;
725
726invalid_key:
727    key_ref_put(key_ref);
728    key_ref = ERR_PTR(ret);
729    goto error;
730
731    /* if we attempted to install a keyring, then it may have caused new
732     * creds to be installed */
733reget_creds:
734    put_cred(cred);
735    goto try_again;
736}
737
738/*
739 * Join the named keyring as the session keyring if possible else attempt to
740 * create a new one of that name and join that.
741 *
742 * If the name is NULL, an empty anonymous keyring will be installed as the
743 * session keyring.
744 *
745 * Named session keyrings are joined with a semaphore held to prevent the
746 * keyrings from going away whilst the attempt is made to going them and also
747 * to prevent a race in creating compatible session keyrings.
748 */
749long join_session_keyring(const char *name)
750{
751    const struct cred *old;
752    struct cred *new;
753    struct key *keyring;
754    long ret, serial;
755
756    /* only permit this if there's a single thread in the thread group -
757     * this avoids us having to adjust the creds on all threads and risking
758     * ENOMEM */
759    if (!current_is_single_threaded())
760        return -EMLINK;
761
762    new = prepare_creds();
763    if (!new)
764        return -ENOMEM;
765    old = current_cred();
766
767    /* if no name is provided, install an anonymous keyring */
768    if (!name) {
769        ret = install_session_keyring_to_cred(new, NULL);
770        if (ret < 0)
771            goto error;
772
773        serial = new->tgcred->session_keyring->serial;
774        ret = commit_creds(new);
775        if (ret == 0)
776            ret = serial;
777        goto okay;
778    }
779
780    /* allow the user to join or create a named keyring */
781    mutex_lock(&key_session_mutex);
782
783    /* look for an existing keyring of this name */
784    keyring = find_keyring_by_name(name, false);
785    if (PTR_ERR(keyring) == -ENOKEY) {
786        /* not found - try and create a new one */
787        keyring = keyring_alloc(name, old->uid, old->gid, old,
788                    KEY_ALLOC_IN_QUOTA, NULL);
789        if (IS_ERR(keyring)) {
790            ret = PTR_ERR(keyring);
791            goto error2;
792        }
793    } else if (IS_ERR(keyring)) {
794        ret = PTR_ERR(keyring);
795        goto error2;
796    }
797
798    /* we've got a keyring - now to install it */
799    ret = install_session_keyring_to_cred(new, keyring);
800    if (ret < 0)
801        goto error2;
802
803    commit_creds(new);
804    mutex_unlock(&key_session_mutex);
805
806    ret = keyring->serial;
807    key_put(keyring);
808okay:
809    return ret;
810
811error2:
812    mutex_unlock(&key_session_mutex);
813error:
814    abort_creds(new);
815    return ret;
816}
817
818/*
819 * Replace a process's session keyring on behalf of one of its children when
820 * the target process is about to resume userspace execution.
821 */
822void key_replace_session_keyring(void)
823{
824    const struct cred *old;
825    struct cred *new;
826
827    if (!current->replacement_session_keyring)
828        return;
829
830    write_lock_irq(&tasklist_lock);
831    new = current->replacement_session_keyring;
832    current->replacement_session_keyring = NULL;
833    write_unlock_irq(&tasklist_lock);
834
835    if (!new)
836        return;
837
838    old = current_cred();
839    new-> uid = old-> uid;
840    new-> euid = old-> euid;
841    new-> suid = old-> suid;
842    new->fsuid = old->fsuid;
843    new-> gid = old-> gid;
844    new-> egid = old-> egid;
845    new-> sgid = old-> sgid;
846    new->fsgid = old->fsgid;
847    new->user = get_uid(old->user);
848    new->group_info = get_group_info(old->group_info);
849
850    new->securebits = old->securebits;
851    new->cap_inheritable = old->cap_inheritable;
852    new->cap_permitted = old->cap_permitted;
853    new->cap_effective = old->cap_effective;
854    new->cap_bset = old->cap_bset;
855
856    new->jit_keyring = old->jit_keyring;
857    new->thread_keyring = key_get(old->thread_keyring);
858    new->tgcred->tgid = old->tgcred->tgid;
859    new->tgcred->process_keyring = key_get(old->tgcred->process_keyring);
860
861    security_transfer_creds(new, old);
862
863    commit_creds(new);
864}
865

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