2 * This program is free software; you can redistribute it and/or
3 * modify it under the terms of the GNU General Public License as
4 * published by the Free Software Foundation, version 2 of the
8 #include <linux/export.h>
9 #include <linux/nsproxy.h>
10 #include <linux/slab.h>
11 #include <linux/user_namespace.h>
12 #include <linux/proc_ns.h>
13 #include <linux/highuid.h>
14 #include <linux/cred.h>
15 #include <linux/securebits.h>
16 #include <linux/keyctl.h>
17 #include <linux/key-type.h>
18 #include <keys/user-type.h>
19 #include <linux/seq_file.h>
21 #include <linux/uaccess.h>
22 #include <linux/ctype.h>
23 #include <linux/projid.h>
24 #include <linux/fs_struct.h>
26 static struct kmem_cache
*user_ns_cachep __read_mostly
;
28 static bool new_idmap_permitted(const struct file
*file
,
29 struct user_namespace
*ns
, int cap_setid
,
30 struct uid_gid_map
*map
);
32 static void set_cred_user_ns(struct cred
*cred
, struct user_namespace
*user_ns
)
34 /* Start with the same capabilities as init but useless for doing
35 * anything as the capabilities are bound to the new user namespace.
37 cred
->securebits
= SECUREBITS_DEFAULT
;
38 cred
->cap_inheritable
= CAP_EMPTY_SET
;
39 cred
->cap_permitted
= CAP_FULL_SET
;
40 cred
->cap_effective
= CAP_FULL_SET
;
41 cred
->cap_bset
= CAP_FULL_SET
;
43 key_put(cred
->request_key_auth
);
44 cred
->request_key_auth
= NULL
;
46 /* tgcred will be cleared in our caller bc CLONE_THREAD won't be set */
47 cred
->user_ns
= user_ns
;
51 * Create a new user namespace, deriving the creator from the user in the
52 * passed credentials, and replacing that user with the new root user for the
55 * This is called by copy_creds(), which will finish setting the target task's
58 int create_user_ns(struct cred
*new)
60 struct user_namespace
*ns
, *parent_ns
= new->user_ns
;
61 kuid_t owner
= new->euid
;
62 kgid_t group
= new->egid
;
65 if (parent_ns
->level
> 32)
69 * Verify that we can not violate the policy of which files
70 * may be accessed that is specified by the root directory,
71 * by verifing that the root directory is at the root of the
72 * mount namespace which allows all files to be accessed.
74 if (current_chrooted())
77 /* The creator needs a mapping in the parent user namespace
78 * or else we won't be able to reasonably tell userspace who
79 * created a user_namespace.
81 if (!kuid_has_mapping(parent_ns
, owner
) ||
82 !kgid_has_mapping(parent_ns
, group
))
85 ns
= kmem_cache_zalloc(user_ns_cachep
, GFP_KERNEL
);
89 ret
= proc_alloc_inum(&ns
->proc_inum
);
91 kmem_cache_free(user_ns_cachep
, ns
);
95 atomic_set(&ns
->count
, 1);
96 /* Leave the new->user_ns reference with the new user namespace. */
97 ns
->parent
= parent_ns
;
98 ns
->level
= parent_ns
->level
+ 1;
102 set_cred_user_ns(new, ns
);
104 #ifdef CONFIG_PERSISTENT_KEYRINGS
105 init_rwsem(&ns
->persistent_keyring_register_sem
);
110 int unshare_userns(unsigned long unshare_flags
, struct cred
**new_cred
)
115 if (!(unshare_flags
& CLONE_NEWUSER
))
118 cred
= prepare_creds();
120 err
= create_user_ns(cred
);
130 void free_user_ns(struct user_namespace
*ns
)
132 struct user_namespace
*parent
;
136 #ifdef CONFIG_PERSISTENT_KEYRINGS
137 key_put(ns
->persistent_keyring_register
);
139 proc_free_inum(ns
->proc_inum
);
140 kmem_cache_free(user_ns_cachep
, ns
);
142 } while (atomic_dec_and_test(&parent
->count
));
144 EXPORT_SYMBOL(free_user_ns
);
146 static u32
map_id_range_down(struct uid_gid_map
*map
, u32 id
, u32 count
)
148 unsigned idx
, extents
;
149 u32 first
, last
, id2
;
151 id2
= id
+ count
- 1;
153 /* Find the matching extent */
154 extents
= map
->nr_extents
;
155 smp_read_barrier_depends();
156 for (idx
= 0; idx
< extents
; idx
++) {
157 first
= map
->extent
[idx
].first
;
158 last
= first
+ map
->extent
[idx
].count
- 1;
159 if (id
>= first
&& id
<= last
&&
160 (id2
>= first
&& id2
<= last
))
163 /* Map the id or note failure */
165 id
= (id
- first
) + map
->extent
[idx
].lower_first
;
172 static u32
map_id_down(struct uid_gid_map
*map
, u32 id
)
174 unsigned idx
, extents
;
177 /* Find the matching extent */
178 extents
= map
->nr_extents
;
179 smp_read_barrier_depends();
180 for (idx
= 0; idx
< extents
; idx
++) {
181 first
= map
->extent
[idx
].first
;
182 last
= first
+ map
->extent
[idx
].count
- 1;
183 if (id
>= first
&& id
<= last
)
186 /* Map the id or note failure */
188 id
= (id
- first
) + map
->extent
[idx
].lower_first
;
195 static u32
map_id_up(struct uid_gid_map
*map
, u32 id
)
197 unsigned idx
, extents
;
200 /* Find the matching extent */
201 extents
= map
->nr_extents
;
202 smp_read_barrier_depends();
203 for (idx
= 0; idx
< extents
; idx
++) {
204 first
= map
->extent
[idx
].lower_first
;
205 last
= first
+ map
->extent
[idx
].count
- 1;
206 if (id
>= first
&& id
<= last
)
209 /* Map the id or note failure */
211 id
= (id
- first
) + map
->extent
[idx
].first
;
219 * make_kuid - Map a user-namespace uid pair into a kuid.
220 * @ns: User namespace that the uid is in
221 * @uid: User identifier
223 * Maps a user-namespace uid pair into a kernel internal kuid,
224 * and returns that kuid.
226 * When there is no mapping defined for the user-namespace uid
227 * pair INVALID_UID is returned. Callers are expected to test
228 * for and handle handle INVALID_UID being returned. INVALID_UID
229 * may be tested for using uid_valid().
231 kuid_t
make_kuid(struct user_namespace
*ns
, uid_t uid
)
233 /* Map the uid to a global kernel uid */
234 return KUIDT_INIT(map_id_down(&ns
->uid_map
, uid
));
236 EXPORT_SYMBOL(make_kuid
);
239 * from_kuid - Create a uid from a kuid user-namespace pair.
240 * @targ: The user namespace we want a uid in.
241 * @kuid: The kernel internal uid to start with.
243 * Map @kuid into the user-namespace specified by @targ and
244 * return the resulting uid.
246 * There is always a mapping into the initial user_namespace.
248 * If @kuid has no mapping in @targ (uid_t)-1 is returned.
250 uid_t
from_kuid(struct user_namespace
*targ
, kuid_t kuid
)
252 /* Map the uid from a global kernel uid */
253 return map_id_up(&targ
->uid_map
, __kuid_val(kuid
));
255 EXPORT_SYMBOL(from_kuid
);
258 * from_kuid_munged - Create a uid from a kuid user-namespace pair.
259 * @targ: The user namespace we want a uid in.
260 * @kuid: The kernel internal uid to start with.
262 * Map @kuid into the user-namespace specified by @targ and
263 * return the resulting uid.
265 * There is always a mapping into the initial user_namespace.
267 * Unlike from_kuid from_kuid_munged never fails and always
268 * returns a valid uid. This makes from_kuid_munged appropriate
269 * for use in syscalls like stat and getuid where failing the
270 * system call and failing to provide a valid uid are not an
273 * If @kuid has no mapping in @targ overflowuid is returned.
275 uid_t
from_kuid_munged(struct user_namespace
*targ
, kuid_t kuid
)
278 uid
= from_kuid(targ
, kuid
);
280 if (uid
== (uid_t
) -1)
284 EXPORT_SYMBOL(from_kuid_munged
);
287 * make_kgid - Map a user-namespace gid pair into a kgid.
288 * @ns: User namespace that the gid is in
289 * @uid: group identifier
291 * Maps a user-namespace gid pair into a kernel internal kgid,
292 * and returns that kgid.
294 * When there is no mapping defined for the user-namespace gid
295 * pair INVALID_GID is returned. Callers are expected to test
296 * for and handle INVALID_GID being returned. INVALID_GID may be
297 * tested for using gid_valid().
299 kgid_t
make_kgid(struct user_namespace
*ns
, gid_t gid
)
301 /* Map the gid to a global kernel gid */
302 return KGIDT_INIT(map_id_down(&ns
->gid_map
, gid
));
304 EXPORT_SYMBOL(make_kgid
);
307 * from_kgid - Create a gid from a kgid user-namespace pair.
308 * @targ: The user namespace we want a gid in.
309 * @kgid: The kernel internal gid to start with.
311 * Map @kgid into the user-namespace specified by @targ and
312 * return the resulting gid.
314 * There is always a mapping into the initial user_namespace.
316 * If @kgid has no mapping in @targ (gid_t)-1 is returned.
318 gid_t
from_kgid(struct user_namespace
*targ
, kgid_t kgid
)
320 /* Map the gid from a global kernel gid */
321 return map_id_up(&targ
->gid_map
, __kgid_val(kgid
));
323 EXPORT_SYMBOL(from_kgid
);
326 * from_kgid_munged - Create a gid from a kgid user-namespace pair.
327 * @targ: The user namespace we want a gid in.
328 * @kgid: The kernel internal gid to start with.
330 * Map @kgid into the user-namespace specified by @targ and
331 * return the resulting gid.
333 * There is always a mapping into the initial user_namespace.
335 * Unlike from_kgid from_kgid_munged never fails and always
336 * returns a valid gid. This makes from_kgid_munged appropriate
337 * for use in syscalls like stat and getgid where failing the
338 * system call and failing to provide a valid gid are not options.
340 * If @kgid has no mapping in @targ overflowgid is returned.
342 gid_t
from_kgid_munged(struct user_namespace
*targ
, kgid_t kgid
)
345 gid
= from_kgid(targ
, kgid
);
347 if (gid
== (gid_t
) -1)
351 EXPORT_SYMBOL(from_kgid_munged
);
354 * make_kprojid - Map a user-namespace projid pair into a kprojid.
355 * @ns: User namespace that the projid is in
356 * @projid: Project identifier
358 * Maps a user-namespace uid pair into a kernel internal kuid,
359 * and returns that kuid.
361 * When there is no mapping defined for the user-namespace projid
362 * pair INVALID_PROJID is returned. Callers are expected to test
363 * for and handle handle INVALID_PROJID being returned. INVALID_PROJID
364 * may be tested for using projid_valid().
366 kprojid_t
make_kprojid(struct user_namespace
*ns
, projid_t projid
)
368 /* Map the uid to a global kernel uid */
369 return KPROJIDT_INIT(map_id_down(&ns
->projid_map
, projid
));
371 EXPORT_SYMBOL(make_kprojid
);
374 * from_kprojid - Create a projid from a kprojid user-namespace pair.
375 * @targ: The user namespace we want a projid in.
376 * @kprojid: The kernel internal project identifier to start with.
378 * Map @kprojid into the user-namespace specified by @targ and
379 * return the resulting projid.
381 * There is always a mapping into the initial user_namespace.
383 * If @kprojid has no mapping in @targ (projid_t)-1 is returned.
385 projid_t
from_kprojid(struct user_namespace
*targ
, kprojid_t kprojid
)
387 /* Map the uid from a global kernel uid */
388 return map_id_up(&targ
->projid_map
, __kprojid_val(kprojid
));
390 EXPORT_SYMBOL(from_kprojid
);
393 * from_kprojid_munged - Create a projiid from a kprojid user-namespace pair.
394 * @targ: The user namespace we want a projid in.
395 * @kprojid: The kernel internal projid to start with.
397 * Map @kprojid into the user-namespace specified by @targ and
398 * return the resulting projid.
400 * There is always a mapping into the initial user_namespace.
402 * Unlike from_kprojid from_kprojid_munged never fails and always
403 * returns a valid projid. This makes from_kprojid_munged
404 * appropriate for use in syscalls like stat and where
405 * failing the system call and failing to provide a valid projid are
408 * If @kprojid has no mapping in @targ OVERFLOW_PROJID is returned.
410 projid_t
from_kprojid_munged(struct user_namespace
*targ
, kprojid_t kprojid
)
413 projid
= from_kprojid(targ
, kprojid
);
415 if (projid
== (projid_t
) -1)
416 projid
= OVERFLOW_PROJID
;
419 EXPORT_SYMBOL(from_kprojid_munged
);
422 static int uid_m_show(struct seq_file
*seq
, void *v
)
424 struct user_namespace
*ns
= seq
->private;
425 struct uid_gid_extent
*extent
= v
;
426 struct user_namespace
*lower_ns
;
429 lower_ns
= seq_user_ns(seq
);
430 if ((lower_ns
== ns
) && lower_ns
->parent
)
431 lower_ns
= lower_ns
->parent
;
433 lower
= from_kuid(lower_ns
, KUIDT_INIT(extent
->lower_first
));
435 seq_printf(seq
, "%10u %10u %10u\n",
443 static int gid_m_show(struct seq_file
*seq
, void *v
)
445 struct user_namespace
*ns
= seq
->private;
446 struct uid_gid_extent
*extent
= v
;
447 struct user_namespace
*lower_ns
;
450 lower_ns
= seq_user_ns(seq
);
451 if ((lower_ns
== ns
) && lower_ns
->parent
)
452 lower_ns
= lower_ns
->parent
;
454 lower
= from_kgid(lower_ns
, KGIDT_INIT(extent
->lower_first
));
456 seq_printf(seq
, "%10u %10u %10u\n",
464 static int projid_m_show(struct seq_file
*seq
, void *v
)
466 struct user_namespace
*ns
= seq
->private;
467 struct uid_gid_extent
*extent
= v
;
468 struct user_namespace
*lower_ns
;
471 lower_ns
= seq_user_ns(seq
);
472 if ((lower_ns
== ns
) && lower_ns
->parent
)
473 lower_ns
= lower_ns
->parent
;
475 lower
= from_kprojid(lower_ns
, KPROJIDT_INIT(extent
->lower_first
));
477 seq_printf(seq
, "%10u %10u %10u\n",
485 static void *m_start(struct seq_file
*seq
, loff_t
*ppos
, struct uid_gid_map
*map
)
487 struct uid_gid_extent
*extent
= NULL
;
490 if (pos
< map
->nr_extents
)
491 extent
= &map
->extent
[pos
];
496 static void *uid_m_start(struct seq_file
*seq
, loff_t
*ppos
)
498 struct user_namespace
*ns
= seq
->private;
500 return m_start(seq
, ppos
, &ns
->uid_map
);
503 static void *gid_m_start(struct seq_file
*seq
, loff_t
*ppos
)
505 struct user_namespace
*ns
= seq
->private;
507 return m_start(seq
, ppos
, &ns
->gid_map
);
510 static void *projid_m_start(struct seq_file
*seq
, loff_t
*ppos
)
512 struct user_namespace
*ns
= seq
->private;
514 return m_start(seq
, ppos
, &ns
->projid_map
);
517 static void *m_next(struct seq_file
*seq
, void *v
, loff_t
*pos
)
520 return seq
->op
->start(seq
, pos
);
523 static void m_stop(struct seq_file
*seq
, void *v
)
528 struct seq_operations proc_uid_seq_operations
= {
529 .start
= uid_m_start
,
535 struct seq_operations proc_gid_seq_operations
= {
536 .start
= gid_m_start
,
542 struct seq_operations proc_projid_seq_operations
= {
543 .start
= projid_m_start
,
546 .show
= projid_m_show
,
549 static bool mappings_overlap(struct uid_gid_map
*new_map
, struct uid_gid_extent
*extent
)
551 u32 upper_first
, lower_first
, upper_last
, lower_last
;
554 upper_first
= extent
->first
;
555 lower_first
= extent
->lower_first
;
556 upper_last
= upper_first
+ extent
->count
- 1;
557 lower_last
= lower_first
+ extent
->count
- 1;
559 for (idx
= 0; idx
< new_map
->nr_extents
; idx
++) {
560 u32 prev_upper_first
, prev_lower_first
;
561 u32 prev_upper_last
, prev_lower_last
;
562 struct uid_gid_extent
*prev
;
564 prev
= &new_map
->extent
[idx
];
566 prev_upper_first
= prev
->first
;
567 prev_lower_first
= prev
->lower_first
;
568 prev_upper_last
= prev_upper_first
+ prev
->count
- 1;
569 prev_lower_last
= prev_lower_first
+ prev
->count
- 1;
571 /* Does the upper range intersect a previous extent? */
572 if ((prev_upper_first
<= upper_last
) &&
573 (prev_upper_last
>= upper_first
))
576 /* Does the lower range intersect a previous extent? */
577 if ((prev_lower_first
<= lower_last
) &&
578 (prev_lower_last
>= lower_first
))
585 static DEFINE_MUTEX(id_map_mutex
);
587 static ssize_t
map_write(struct file
*file
, const char __user
*buf
,
588 size_t count
, loff_t
*ppos
,
590 struct uid_gid_map
*map
,
591 struct uid_gid_map
*parent_map
)
593 struct seq_file
*seq
= file
->private_data
;
594 struct user_namespace
*ns
= seq
->private;
595 struct uid_gid_map new_map
;
597 struct uid_gid_extent
*extent
= NULL
;
598 unsigned long page
= 0;
599 char *kbuf
, *pos
, *next_line
;
600 ssize_t ret
= -EINVAL
;
603 * The id_map_mutex serializes all writes to any given map.
605 * Any map is only ever written once.
607 * An id map fits within 1 cache line on most architectures.
609 * On read nothing needs to be done unless you are on an
610 * architecture with a crazy cache coherency model like alpha.
612 * There is a one time data dependency between reading the
613 * count of the extents and the values of the extents. The
614 * desired behavior is to see the values of the extents that
615 * were written before the count of the extents.
617 * To achieve this smp_wmb() is used on guarantee the write
618 * order and smp_read_barrier_depends() is guaranteed that we
619 * don't have crazy architectures returning stale data.
622 mutex_lock(&id_map_mutex
);
625 /* Only allow one successful write to the map */
626 if (map
->nr_extents
!= 0)
630 * Adjusting namespace settings requires capabilities on the target.
632 if (cap_valid(cap_setid
) && !file_ns_capable(file
, ns
, CAP_SYS_ADMIN
))
637 page
= __get_free_page(GFP_TEMPORARY
);
638 kbuf
= (char *) page
;
642 /* Only allow <= page size writes at the beginning of the file */
644 if ((*ppos
!= 0) || (count
>= PAGE_SIZE
))
647 /* Slurp in the user data */
649 if (copy_from_user(kbuf
, buf
, count
))
653 /* Parse the user data */
656 new_map
.nr_extents
= 0;
657 for (;pos
; pos
= next_line
) {
658 extent
= &new_map
.extent
[new_map
.nr_extents
];
660 /* Find the end of line and ensure I don't look past it */
661 next_line
= strchr(pos
, '\n');
665 if (*next_line
== '\0')
669 pos
= skip_spaces(pos
);
670 extent
->first
= simple_strtoul(pos
, &pos
, 10);
674 pos
= skip_spaces(pos
);
675 extent
->lower_first
= simple_strtoul(pos
, &pos
, 10);
679 pos
= skip_spaces(pos
);
680 extent
->count
= simple_strtoul(pos
, &pos
, 10);
681 if (*pos
&& !isspace(*pos
))
684 /* Verify there is not trailing junk on the line */
685 pos
= skip_spaces(pos
);
689 /* Verify we have been given valid starting values */
690 if ((extent
->first
== (u32
) -1) ||
691 (extent
->lower_first
== (u32
) -1 ))
694 /* Verify count is not zero and does not cause the extent to wrap */
695 if ((extent
->first
+ extent
->count
) <= extent
->first
)
697 if ((extent
->lower_first
+ extent
->count
) <= extent
->lower_first
)
700 /* Do the ranges in extent overlap any previous extents? */
701 if (mappings_overlap(&new_map
, extent
))
704 new_map
.nr_extents
++;
706 /* Fail if the file contains too many extents */
707 if ((new_map
.nr_extents
== UID_GID_MAP_MAX_EXTENTS
) &&
711 /* Be very certaint the new map actually exists */
712 if (new_map
.nr_extents
== 0)
716 /* Validate the user is allowed to use user id's mapped to. */
717 if (!new_idmap_permitted(file
, ns
, cap_setid
, &new_map
))
720 /* Map the lower ids from the parent user namespace to the
721 * kernel global id space.
723 for (idx
= 0; idx
< new_map
.nr_extents
; idx
++) {
725 extent
= &new_map
.extent
[idx
];
727 lower_first
= map_id_range_down(parent_map
,
731 /* Fail if we can not map the specified extent to
732 * the kernel global id space.
734 if (lower_first
== (u32
) -1)
737 extent
->lower_first
= lower_first
;
740 /* Install the map */
741 memcpy(map
->extent
, new_map
.extent
,
742 new_map
.nr_extents
*sizeof(new_map
.extent
[0]));
744 map
->nr_extents
= new_map
.nr_extents
;
749 mutex_unlock(&id_map_mutex
);
755 ssize_t
proc_uid_map_write(struct file
*file
, const char __user
*buf
, size_t size
, loff_t
*ppos
)
757 struct seq_file
*seq
= file
->private_data
;
758 struct user_namespace
*ns
= seq
->private;
759 struct user_namespace
*seq_ns
= seq_user_ns(seq
);
764 if ((seq_ns
!= ns
) && (seq_ns
!= ns
->parent
))
767 return map_write(file
, buf
, size
, ppos
, CAP_SETUID
,
768 &ns
->uid_map
, &ns
->parent
->uid_map
);
771 ssize_t
proc_gid_map_write(struct file
*file
, const char __user
*buf
, size_t size
, loff_t
*ppos
)
773 struct seq_file
*seq
= file
->private_data
;
774 struct user_namespace
*ns
= seq
->private;
775 struct user_namespace
*seq_ns
= seq_user_ns(seq
);
780 if ((seq_ns
!= ns
) && (seq_ns
!= ns
->parent
))
783 return map_write(file
, buf
, size
, ppos
, CAP_SETGID
,
784 &ns
->gid_map
, &ns
->parent
->gid_map
);
787 ssize_t
proc_projid_map_write(struct file
*file
, const char __user
*buf
, size_t size
, loff_t
*ppos
)
789 struct seq_file
*seq
= file
->private_data
;
790 struct user_namespace
*ns
= seq
->private;
791 struct user_namespace
*seq_ns
= seq_user_ns(seq
);
796 if ((seq_ns
!= ns
) && (seq_ns
!= ns
->parent
))
799 /* Anyone can set any valid project id no capability needed */
800 return map_write(file
, buf
, size
, ppos
, -1,
801 &ns
->projid_map
, &ns
->parent
->projid_map
);
804 static bool new_idmap_permitted(const struct file
*file
,
805 struct user_namespace
*ns
, int cap_setid
,
806 struct uid_gid_map
*new_map
)
808 /* Allow mapping to your own filesystem ids */
809 if ((new_map
->nr_extents
== 1) && (new_map
->extent
[0].count
== 1)) {
810 u32 id
= new_map
->extent
[0].lower_first
;
811 if (cap_setid
== CAP_SETUID
) {
812 kuid_t uid
= make_kuid(ns
->parent
, id
);
813 if (uid_eq(uid
, file
->f_cred
->fsuid
))
816 else if (cap_setid
== CAP_SETGID
) {
817 kgid_t gid
= make_kgid(ns
->parent
, id
);
818 if (gid_eq(gid
, file
->f_cred
->fsgid
))
823 /* Allow anyone to set a mapping that doesn't require privilege */
824 if (!cap_valid(cap_setid
))
827 /* Allow the specified ids if we have the appropriate capability
828 * (CAP_SETUID or CAP_SETGID) over the parent user namespace.
829 * And the opener of the id file also had the approprpiate capability.
831 if (ns_capable(ns
->parent
, cap_setid
) &&
832 file_ns_capable(file
, ns
->parent
, cap_setid
))
838 static void *userns_get(struct task_struct
*task
)
840 struct user_namespace
*user_ns
;
843 user_ns
= get_user_ns(__task_cred(task
)->user_ns
);
849 static void userns_put(void *ns
)
854 static int userns_install(struct nsproxy
*nsproxy
, void *ns
)
856 struct user_namespace
*user_ns
= ns
;
859 /* Don't allow gaining capabilities by reentering
860 * the same user namespace.
862 if (user_ns
== current_user_ns())
865 /* Threaded processes may not enter a different user namespace */
866 if (atomic_read(¤t
->mm
->mm_users
) > 1)
869 if (current
->fs
->users
!= 1)
872 if (!ns_capable(user_ns
, CAP_SYS_ADMIN
))
875 cred
= prepare_creds();
879 put_user_ns(cred
->user_ns
);
880 set_cred_user_ns(cred
, get_user_ns(user_ns
));
882 return commit_creds(cred
);
885 static unsigned int userns_inum(void *ns
)
887 struct user_namespace
*user_ns
= ns
;
888 return user_ns
->proc_inum
;
891 const struct proc_ns_operations userns_operations
= {
893 .type
= CLONE_NEWUSER
,
896 .install
= userns_install
,
900 static __init
int user_namespaces_init(void)
902 user_ns_cachep
= KMEM_CACHE(user_namespace
, SLAB_PANIC
);
905 module_init(user_namespaces_init
);