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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2006 IBM Corporation
4 *
5 * Author: Serge Hallyn <serue@us.ibm.com>
6 *
7 * Jun 2006 - namespaces support
8 * OpenVZ, SWsoft Inc.
9 * Pavel Emelianov <xemul@openvz.org>
10 */
11
12#include <linux/slab.h>
13#include <linux/export.h>
14#include <linux/nsproxy.h>
15#include <linux/init_task.h>
16#include <linux/mnt_namespace.h>
17#include <linux/utsname.h>
18#include <linux/pid_namespace.h>
19#include <net/net_namespace.h>
20#include <linux/ipc_namespace.h>
21#include <linux/time_namespace.h>
22#include <linux/fs_struct.h>
23#include <linux/proc_fs.h>
24#include <linux/proc_ns.h>
25#include <linux/file.h>
26#include <linux/syscalls.h>
27#include <linux/cgroup.h>
28#include <linux/perf_event.h>
29
30static struct kmem_cache *nsproxy_cachep;
31
32struct nsproxy init_nsproxy = {
33 .count = ATOMIC_INIT(1),
34 .uts_ns = &init_uts_ns,
35#if defined(CONFIG_POSIX_MQUEUE) || defined(CONFIG_SYSVIPC)
36 .ipc_ns = &init_ipc_ns,
37#endif
38 .mnt_ns = NULL,
39 .pid_ns_for_children = &init_pid_ns,
40#ifdef CONFIG_NET
41 .net_ns = &init_net,
42#endif
43#ifdef CONFIG_CGROUPS
44 .cgroup_ns = &init_cgroup_ns,
45#endif
46#ifdef CONFIG_TIME_NS
47 .time_ns = &init_time_ns,
48 .time_ns_for_children = &init_time_ns,
49#endif
50};
51
52static inline struct nsproxy *create_nsproxy(void)
53{
54 struct nsproxy *nsproxy;
55
56 nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
57 if (nsproxy)
58 atomic_set(&nsproxy->count, 1);
59 return nsproxy;
60}
61
62/*
63 * Create new nsproxy and all of its the associated namespaces.
64 * Return the newly created nsproxy. Do not attach this to the task,
65 * leave it to the caller to do proper locking and attach it to task.
66 */
67static struct nsproxy *create_new_namespaces(unsigned long flags,
68 struct task_struct *tsk, struct user_namespace *user_ns,
69 struct fs_struct *new_fs)
70{
71 struct nsproxy *new_nsp;
72 int err;
73
74 new_nsp = create_nsproxy();
75 if (!new_nsp)
76 return ERR_PTR(-ENOMEM);
77
78 new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, user_ns, new_fs);
79 if (IS_ERR(new_nsp->mnt_ns)) {
80 err = PTR_ERR(new_nsp->mnt_ns);
81 goto out_ns;
82 }
83
84 new_nsp->uts_ns = copy_utsname(flags, user_ns, tsk->nsproxy->uts_ns);
85 if (IS_ERR(new_nsp->uts_ns)) {
86 err = PTR_ERR(new_nsp->uts_ns);
87 goto out_uts;
88 }
89
90 new_nsp->ipc_ns = copy_ipcs(flags, user_ns, tsk->nsproxy->ipc_ns);
91 if (IS_ERR(new_nsp->ipc_ns)) {
92 err = PTR_ERR(new_nsp->ipc_ns);
93 goto out_ipc;
94 }
95
96 new_nsp->pid_ns_for_children =
97 copy_pid_ns(flags, user_ns, tsk->nsproxy->pid_ns_for_children);
98 if (IS_ERR(new_nsp->pid_ns_for_children)) {
99 err = PTR_ERR(new_nsp->pid_ns_for_children);
100 goto out_pid;
101 }
102
103 new_nsp->cgroup_ns = copy_cgroup_ns(flags, user_ns,
104 tsk->nsproxy->cgroup_ns);
105 if (IS_ERR(new_nsp->cgroup_ns)) {
106 err = PTR_ERR(new_nsp->cgroup_ns);
107 goto out_cgroup;
108 }
109
110 new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);
111 if (IS_ERR(new_nsp->net_ns)) {
112 err = PTR_ERR(new_nsp->net_ns);
113 goto out_net;
114 }
115
116 new_nsp->time_ns_for_children = copy_time_ns(flags, user_ns,
117 tsk->nsproxy->time_ns_for_children);
118 if (IS_ERR(new_nsp->time_ns_for_children)) {
119 err = PTR_ERR(new_nsp->time_ns_for_children);
120 goto out_time;
121 }
122 new_nsp->time_ns = get_time_ns(tsk->nsproxy->time_ns);
123
124 return new_nsp;
125
126out_time:
127 put_net(new_nsp->net_ns);
128out_net:
129 put_cgroup_ns(new_nsp->cgroup_ns);
130out_cgroup:
131 if (new_nsp->pid_ns_for_children)
132 put_pid_ns(new_nsp->pid_ns_for_children);
133out_pid:
134 if (new_nsp->ipc_ns)
135 put_ipc_ns(new_nsp->ipc_ns);
136out_ipc:
137 if (new_nsp->uts_ns)
138 put_uts_ns(new_nsp->uts_ns);
139out_uts:
140 if (new_nsp->mnt_ns)
141 put_mnt_ns(new_nsp->mnt_ns);
142out_ns:
143 kmem_cache_free(nsproxy_cachep, new_nsp);
144 return ERR_PTR(err);
145}
146
147/*
148 * called from clone. This now handles copy for nsproxy and all
149 * namespaces therein.
150 */
151int copy_namespaces(unsigned long flags, struct task_struct *tsk)
152{
153 struct nsproxy *old_ns = tsk->nsproxy;
154 struct user_namespace *user_ns = task_cred_xxx(tsk, user_ns);
155 struct nsproxy *new_ns;
156
157 if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
158 CLONE_NEWPID | CLONE_NEWNET |
159 CLONE_NEWCGROUP | CLONE_NEWTIME)))) {
160 if ((flags & CLONE_VM) ||
161 likely(old_ns->time_ns_for_children == old_ns->time_ns)) {
162 get_nsproxy(old_ns);
163 return 0;
164 }
165 } else if (!ns_capable(user_ns, CAP_SYS_ADMIN))
166 return -EPERM;
167
168 /*
169 * CLONE_NEWIPC must detach from the undolist: after switching
170 * to a new ipc namespace, the semaphore arrays from the old
171 * namespace are unreachable. In clone parlance, CLONE_SYSVSEM
172 * means share undolist with parent, so we must forbid using
173 * it along with CLONE_NEWIPC.
174 */
175 if ((flags & (CLONE_NEWIPC | CLONE_SYSVSEM)) ==
176 (CLONE_NEWIPC | CLONE_SYSVSEM))
177 return -EINVAL;
178
179 new_ns = create_new_namespaces(flags, tsk, user_ns, tsk->fs);
180 if (IS_ERR(new_ns))
181 return PTR_ERR(new_ns);
182
183 if ((flags & CLONE_VM) == 0)
184 timens_on_fork(new_ns, tsk);
185
186 tsk->nsproxy = new_ns;
187 return 0;
188}
189
190void free_nsproxy(struct nsproxy *ns)
191{
192 if (ns->mnt_ns)
193 put_mnt_ns(ns->mnt_ns);
194 if (ns->uts_ns)
195 put_uts_ns(ns->uts_ns);
196 if (ns->ipc_ns)
197 put_ipc_ns(ns->ipc_ns);
198 if (ns->pid_ns_for_children)
199 put_pid_ns(ns->pid_ns_for_children);
200 if (ns->time_ns)
201 put_time_ns(ns->time_ns);
202 if (ns->time_ns_for_children)
203 put_time_ns(ns->time_ns_for_children);
204 put_cgroup_ns(ns->cgroup_ns);
205 put_net(ns->net_ns);
206 kmem_cache_free(nsproxy_cachep, ns);
207}
208
209/*
210 * Called from unshare. Unshare all the namespaces part of nsproxy.
211 * On success, returns the new nsproxy.
212 */
213int unshare_nsproxy_namespaces(unsigned long unshare_flags,
214 struct nsproxy **new_nsp, struct cred *new_cred, struct fs_struct *new_fs)
215{
216 struct user_namespace *user_ns;
217 int err = 0;
218
219 if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
220 CLONE_NEWNET | CLONE_NEWPID | CLONE_NEWCGROUP |
221 CLONE_NEWTIME)))
222 return 0;
223
224 user_ns = new_cred ? new_cred->user_ns : current_user_ns();
225 if (!ns_capable(user_ns, CAP_SYS_ADMIN))
226 return -EPERM;
227
228 *new_nsp = create_new_namespaces(unshare_flags, current, user_ns,
229 new_fs ? new_fs : current->fs);
230 if (IS_ERR(*new_nsp)) {
231 err = PTR_ERR(*new_nsp);
232 goto out;
233 }
234
235out:
236 return err;
237}
238
239void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)
240{
241 struct nsproxy *ns;
242
243 might_sleep();
244
245 task_lock(p);
246 ns = p->nsproxy;
247 p->nsproxy = new;
248 task_unlock(p);
249
250 if (ns)
251 put_nsproxy(ns);
252}
253
254void exit_task_namespaces(struct task_struct *p)
255{
256 switch_task_namespaces(p, NULL);
257}
258
259int exec_task_namespaces(void)
260{
261 struct task_struct *tsk = current;
262 struct nsproxy *new;
263
264 if (tsk->nsproxy->time_ns_for_children == tsk->nsproxy->time_ns)
265 return 0;
266
267 new = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs);
268 if (IS_ERR(new))
269 return PTR_ERR(new);
270
271 timens_on_fork(new, tsk);
272 switch_task_namespaces(tsk, new);
273 return 0;
274}
275
276static int check_setns_flags(unsigned long flags)
277{
278 if (!flags || (flags & ~(CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
279 CLONE_NEWNET | CLONE_NEWTIME | CLONE_NEWUSER |
280 CLONE_NEWPID | CLONE_NEWCGROUP)))
281 return -EINVAL;
282
283#ifndef CONFIG_USER_NS
284 if (flags & CLONE_NEWUSER)
285 return -EINVAL;
286#endif
287#ifndef CONFIG_PID_NS
288 if (flags & CLONE_NEWPID)
289 return -EINVAL;
290#endif
291#ifndef CONFIG_UTS_NS
292 if (flags & CLONE_NEWUTS)
293 return -EINVAL;
294#endif
295#ifndef CONFIG_IPC_NS
296 if (flags & CLONE_NEWIPC)
297 return -EINVAL;
298#endif
299#ifndef CONFIG_CGROUPS
300 if (flags & CLONE_NEWCGROUP)
301 return -EINVAL;
302#endif
303#ifndef CONFIG_NET_NS
304 if (flags & CLONE_NEWNET)
305 return -EINVAL;
306#endif
307#ifndef CONFIG_TIME_NS
308 if (flags & CLONE_NEWTIME)
309 return -EINVAL;
310#endif
311
312 return 0;
313}
314
315static void put_nsset(struct nsset *nsset)
316{
317 unsigned flags = nsset->flags;
318
319 if (flags & CLONE_NEWUSER)
320 put_cred(nsset_cred(nsset));
321 /*
322 * We only created a temporary copy if we attached to more than just
323 * the mount namespace.
324 */
325 if (nsset->fs && (flags & CLONE_NEWNS) && (flags & ~CLONE_NEWNS))
326 free_fs_struct(nsset->fs);
327 if (nsset->nsproxy)
328 free_nsproxy(nsset->nsproxy);
329}
330
331static int prepare_nsset(unsigned flags, struct nsset *nsset)
332{
333 struct task_struct *me = current;
334
335 nsset->nsproxy = create_new_namespaces(0, me, current_user_ns(), me->fs);
336 if (IS_ERR(nsset->nsproxy))
337 return PTR_ERR(nsset->nsproxy);
338
339 if (flags & CLONE_NEWUSER)
340 nsset->cred = prepare_creds();
341 else
342 nsset->cred = current_cred();
343 if (!nsset->cred)
344 goto out;
345
346 /* Only create a temporary copy of fs_struct if we really need to. */
347 if (flags == CLONE_NEWNS) {
348 nsset->fs = me->fs;
349 } else if (flags & CLONE_NEWNS) {
350 nsset->fs = copy_fs_struct(me->fs);
351 if (!nsset->fs)
352 goto out;
353 }
354
355 nsset->flags = flags;
356 return 0;
357
358out:
359 put_nsset(nsset);
360 return -ENOMEM;
361}
362
363static inline int validate_ns(struct nsset *nsset, struct ns_common *ns)
364{
365 return ns->ops->install(nsset, ns);
366}
367
368/*
369 * This is the inverse operation to unshare().
370 * Ordering is equivalent to the standard ordering used everywhere else
371 * during unshare and process creation. The switch to the new set of
372 * namespaces occurs at the point of no return after installation of
373 * all requested namespaces was successful in commit_nsset().
374 */
375static int validate_nsset(struct nsset *nsset, struct pid *pid)
376{
377 int ret = 0;
378 unsigned flags = nsset->flags;
379 struct user_namespace *user_ns = NULL;
380 struct pid_namespace *pid_ns = NULL;
381 struct nsproxy *nsp;
382 struct task_struct *tsk;
383
384 /* Take a "snapshot" of the target task's namespaces. */
385 rcu_read_lock();
386 tsk = pid_task(pid, PIDTYPE_PID);
387 if (!tsk) {
388 rcu_read_unlock();
389 return -ESRCH;
390 }
391
392 if (!ptrace_may_access(tsk, PTRACE_MODE_READ_REALCREDS)) {
393 rcu_read_unlock();
394 return -EPERM;
395 }
396
397 task_lock(tsk);
398 nsp = tsk->nsproxy;
399 if (nsp)
400 get_nsproxy(nsp);
401 task_unlock(tsk);
402 if (!nsp) {
403 rcu_read_unlock();
404 return -ESRCH;
405 }
406
407#ifdef CONFIG_PID_NS
408 if (flags & CLONE_NEWPID) {
409 pid_ns = task_active_pid_ns(tsk);
410 if (unlikely(!pid_ns)) {
411 rcu_read_unlock();
412 ret = -ESRCH;
413 goto out;
414 }
415 get_pid_ns(pid_ns);
416 }
417#endif
418
419#ifdef CONFIG_USER_NS
420 if (flags & CLONE_NEWUSER)
421 user_ns = get_user_ns(__task_cred(tsk)->user_ns);
422#endif
423 rcu_read_unlock();
424
425 /*
426 * Install requested namespaces. The caller will have
427 * verified earlier that the requested namespaces are
428 * supported on this kernel. We don't report errors here
429 * if a namespace is requested that isn't supported.
430 */
431#ifdef CONFIG_USER_NS
432 if (flags & CLONE_NEWUSER) {
433 ret = validate_ns(nsset, &user_ns->ns);
434 if (ret)
435 goto out;
436 }
437#endif
438
439 if (flags & CLONE_NEWNS) {
440 ret = validate_ns(nsset, from_mnt_ns(nsp->mnt_ns));
441 if (ret)
442 goto out;
443 }
444
445#ifdef CONFIG_UTS_NS
446 if (flags & CLONE_NEWUTS) {
447 ret = validate_ns(nsset, &nsp->uts_ns->ns);
448 if (ret)
449 goto out;
450 }
451#endif
452
453#ifdef CONFIG_IPC_NS
454 if (flags & CLONE_NEWIPC) {
455 ret = validate_ns(nsset, &nsp->ipc_ns->ns);
456 if (ret)
457 goto out;
458 }
459#endif
460
461#ifdef CONFIG_PID_NS
462 if (flags & CLONE_NEWPID) {
463 ret = validate_ns(nsset, &pid_ns->ns);
464 if (ret)
465 goto out;
466 }
467#endif
468
469#ifdef CONFIG_CGROUPS
470 if (flags & CLONE_NEWCGROUP) {
471 ret = validate_ns(nsset, &nsp->cgroup_ns->ns);
472 if (ret)
473 goto out;
474 }
475#endif
476
477#ifdef CONFIG_NET_NS
478 if (flags & CLONE_NEWNET) {
479 ret = validate_ns(nsset, &nsp->net_ns->ns);
480 if (ret)
481 goto out;
482 }
483#endif
484
485#ifdef CONFIG_TIME_NS
486 if (flags & CLONE_NEWTIME) {
487 ret = validate_ns(nsset, &nsp->time_ns->ns);
488 if (ret)
489 goto out;
490 }
491#endif
492
493out:
494 if (pid_ns)
495 put_pid_ns(pid_ns);
496 if (nsp)
497 put_nsproxy(nsp);
498 put_user_ns(user_ns);
499
500 return ret;
501}
502
503/*
504 * This is the point of no return. There are just a few namespaces
505 * that do some actual work here and it's sufficiently minimal that
506 * a separate ns_common operation seems unnecessary for now.
507 * Unshare is doing the same thing. If we'll end up needing to do
508 * more in a given namespace or a helper here is ultimately not
509 * exported anymore a simple commit handler for each namespace
510 * should be added to ns_common.
511 */
512static void commit_nsset(struct nsset *nsset)
513{
514 unsigned flags = nsset->flags;
515 struct task_struct *me = current;
516
517#ifdef CONFIG_USER_NS
518 if (flags & CLONE_NEWUSER) {
519 /* transfer ownership */
520 commit_creds(nsset_cred(nsset));
521 nsset->cred = NULL;
522 }
523#endif
524
525 /* We only need to commit if we have used a temporary fs_struct. */
526 if ((flags & CLONE_NEWNS) && (flags & ~CLONE_NEWNS)) {
527 set_fs_root(me->fs, &nsset->fs->root);
528 set_fs_pwd(me->fs, &nsset->fs->pwd);
529 }
530
531#ifdef CONFIG_IPC_NS
532 if (flags & CLONE_NEWIPC)
533 exit_sem(me);
534#endif
535
536#ifdef CONFIG_TIME_NS
537 if (flags & CLONE_NEWTIME)
538 timens_commit(me, nsset->nsproxy->time_ns);
539#endif
540
541 /* transfer ownership */
542 switch_task_namespaces(me, nsset->nsproxy);
543 nsset->nsproxy = NULL;
544}
545
546SYSCALL_DEFINE2(setns, int, fd, int, flags)
547{
548 struct file *file;
549 struct ns_common *ns = NULL;
550 struct nsset nsset = {};
551 int err = 0;
552
553 file = fget(fd);
554 if (!file)
555 return -EBADF;
556
557 if (proc_ns_file(file)) {
558 ns = get_proc_ns(file_inode(file));
559 if (flags && (ns->ops->type != flags))
560 err = -EINVAL;
561 flags = ns->ops->type;
562 } else if (!IS_ERR(pidfd_pid(file))) {
563 err = check_setns_flags(flags);
564 } else {
565 err = -EINVAL;
566 }
567 if (err)
568 goto out;
569
570 err = prepare_nsset(flags, &nsset);
571 if (err)
572 goto out;
573
574 if (proc_ns_file(file))
575 err = validate_ns(&nsset, ns);
576 else
577 err = validate_nsset(&nsset, file->private_data);
578 if (!err) {
579 commit_nsset(&nsset);
580 perf_event_namespaces(current);
581 }
582 put_nsset(&nsset);
583out:
584 fput(file);
585 return err;
586}
587
588int __init nsproxy_cache_init(void)
589{
590 nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC|SLAB_ACCOUNT);
591 return 0;
592}
1/*
2 * Copyright (C) 2006 IBM Corporation
3 *
4 * Author: Serge Hallyn <serue@us.ibm.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 as
8 * published by the Free Software Foundation, version 2 of the
9 * License.
10 *
11 * Jun 2006 - namespaces support
12 * OpenVZ, SWsoft Inc.
13 * Pavel Emelianov <xemul@openvz.org>
14 */
15
16#include <linux/slab.h>
17#include <linux/module.h>
18#include <linux/nsproxy.h>
19#include <linux/init_task.h>
20#include <linux/mnt_namespace.h>
21#include <linux/utsname.h>
22#include <linux/pid_namespace.h>
23#include <net/net_namespace.h>
24#include <linux/ipc_namespace.h>
25#include <linux/proc_fs.h>
26#include <linux/file.h>
27#include <linux/syscalls.h>
28
29static struct kmem_cache *nsproxy_cachep;
30
31struct nsproxy init_nsproxy = {
32 .count = ATOMIC_INIT(1),
33 .uts_ns = &init_uts_ns,
34#if defined(CONFIG_POSIX_MQUEUE) || defined(CONFIG_SYSVIPC)
35 .ipc_ns = &init_ipc_ns,
36#endif
37 .mnt_ns = NULL,
38 .pid_ns = &init_pid_ns,
39#ifdef CONFIG_NET
40 .net_ns = &init_net,
41#endif
42};
43
44static inline struct nsproxy *create_nsproxy(void)
45{
46 struct nsproxy *nsproxy;
47
48 nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
49 if (nsproxy)
50 atomic_set(&nsproxy->count, 1);
51 return nsproxy;
52}
53
54/*
55 * Create new nsproxy and all of its the associated namespaces.
56 * Return the newly created nsproxy. Do not attach this to the task,
57 * leave it to the caller to do proper locking and attach it to task.
58 */
59static struct nsproxy *create_new_namespaces(unsigned long flags,
60 struct task_struct *tsk, struct fs_struct *new_fs)
61{
62 struct nsproxy *new_nsp;
63 int err;
64
65 new_nsp = create_nsproxy();
66 if (!new_nsp)
67 return ERR_PTR(-ENOMEM);
68
69 new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs);
70 if (IS_ERR(new_nsp->mnt_ns)) {
71 err = PTR_ERR(new_nsp->mnt_ns);
72 goto out_ns;
73 }
74
75 new_nsp->uts_ns = copy_utsname(flags, tsk);
76 if (IS_ERR(new_nsp->uts_ns)) {
77 err = PTR_ERR(new_nsp->uts_ns);
78 goto out_uts;
79 }
80
81 new_nsp->ipc_ns = copy_ipcs(flags, tsk);
82 if (IS_ERR(new_nsp->ipc_ns)) {
83 err = PTR_ERR(new_nsp->ipc_ns);
84 goto out_ipc;
85 }
86
87 new_nsp->pid_ns = copy_pid_ns(flags, task_active_pid_ns(tsk));
88 if (IS_ERR(new_nsp->pid_ns)) {
89 err = PTR_ERR(new_nsp->pid_ns);
90 goto out_pid;
91 }
92
93 new_nsp->net_ns = copy_net_ns(flags, tsk->nsproxy->net_ns);
94 if (IS_ERR(new_nsp->net_ns)) {
95 err = PTR_ERR(new_nsp->net_ns);
96 goto out_net;
97 }
98
99 return new_nsp;
100
101out_net:
102 if (new_nsp->pid_ns)
103 put_pid_ns(new_nsp->pid_ns);
104out_pid:
105 if (new_nsp->ipc_ns)
106 put_ipc_ns(new_nsp->ipc_ns);
107out_ipc:
108 if (new_nsp->uts_ns)
109 put_uts_ns(new_nsp->uts_ns);
110out_uts:
111 if (new_nsp->mnt_ns)
112 put_mnt_ns(new_nsp->mnt_ns);
113out_ns:
114 kmem_cache_free(nsproxy_cachep, new_nsp);
115 return ERR_PTR(err);
116}
117
118/*
119 * called from clone. This now handles copy for nsproxy and all
120 * namespaces therein.
121 */
122int copy_namespaces(unsigned long flags, struct task_struct *tsk)
123{
124 struct nsproxy *old_ns = tsk->nsproxy;
125 struct nsproxy *new_ns;
126 int err = 0;
127
128 if (!old_ns)
129 return 0;
130
131 get_nsproxy(old_ns);
132
133 if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
134 CLONE_NEWPID | CLONE_NEWNET)))
135 return 0;
136
137 if (!capable(CAP_SYS_ADMIN)) {
138 err = -EPERM;
139 goto out;
140 }
141
142 /*
143 * CLONE_NEWIPC must detach from the undolist: after switching
144 * to a new ipc namespace, the semaphore arrays from the old
145 * namespace are unreachable. In clone parlance, CLONE_SYSVSEM
146 * means share undolist with parent, so we must forbid using
147 * it along with CLONE_NEWIPC.
148 */
149 if ((flags & CLONE_NEWIPC) && (flags & CLONE_SYSVSEM)) {
150 err = -EINVAL;
151 goto out;
152 }
153
154 new_ns = create_new_namespaces(flags, tsk, tsk->fs);
155 if (IS_ERR(new_ns)) {
156 err = PTR_ERR(new_ns);
157 goto out;
158 }
159
160 tsk->nsproxy = new_ns;
161
162out:
163 put_nsproxy(old_ns);
164 return err;
165}
166
167void free_nsproxy(struct nsproxy *ns)
168{
169 if (ns->mnt_ns)
170 put_mnt_ns(ns->mnt_ns);
171 if (ns->uts_ns)
172 put_uts_ns(ns->uts_ns);
173 if (ns->ipc_ns)
174 put_ipc_ns(ns->ipc_ns);
175 if (ns->pid_ns)
176 put_pid_ns(ns->pid_ns);
177 put_net(ns->net_ns);
178 kmem_cache_free(nsproxy_cachep, ns);
179}
180
181/*
182 * Called from unshare. Unshare all the namespaces part of nsproxy.
183 * On success, returns the new nsproxy.
184 */
185int unshare_nsproxy_namespaces(unsigned long unshare_flags,
186 struct nsproxy **new_nsp, struct fs_struct *new_fs)
187{
188 int err = 0;
189
190 if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
191 CLONE_NEWNET)))
192 return 0;
193
194 if (!capable(CAP_SYS_ADMIN))
195 return -EPERM;
196
197 *new_nsp = create_new_namespaces(unshare_flags, current,
198 new_fs ? new_fs : current->fs);
199 if (IS_ERR(*new_nsp)) {
200 err = PTR_ERR(*new_nsp);
201 goto out;
202 }
203
204out:
205 return err;
206}
207
208void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)
209{
210 struct nsproxy *ns;
211
212 might_sleep();
213
214 ns = p->nsproxy;
215
216 rcu_assign_pointer(p->nsproxy, new);
217
218 if (ns && atomic_dec_and_test(&ns->count)) {
219 /*
220 * wait for others to get what they want from this nsproxy.
221 *
222 * cannot release this nsproxy via the call_rcu() since
223 * put_mnt_ns() will want to sleep
224 */
225 synchronize_rcu();
226 free_nsproxy(ns);
227 }
228}
229
230void exit_task_namespaces(struct task_struct *p)
231{
232 switch_task_namespaces(p, NULL);
233}
234
235SYSCALL_DEFINE2(setns, int, fd, int, nstype)
236{
237 const struct proc_ns_operations *ops;
238 struct task_struct *tsk = current;
239 struct nsproxy *new_nsproxy;
240 struct proc_inode *ei;
241 struct file *file;
242 int err;
243
244 if (!capable(CAP_SYS_ADMIN))
245 return -EPERM;
246
247 file = proc_ns_fget(fd);
248 if (IS_ERR(file))
249 return PTR_ERR(file);
250
251 err = -EINVAL;
252 ei = PROC_I(file->f_dentry->d_inode);
253 ops = ei->ns_ops;
254 if (nstype && (ops->type != nstype))
255 goto out;
256
257 new_nsproxy = create_new_namespaces(0, tsk, tsk->fs);
258 if (IS_ERR(new_nsproxy)) {
259 err = PTR_ERR(new_nsproxy);
260 goto out;
261 }
262
263 err = ops->install(new_nsproxy, ei->ns);
264 if (err) {
265 free_nsproxy(new_nsproxy);
266 goto out;
267 }
268 switch_task_namespaces(tsk, new_nsproxy);
269out:
270 fput(file);
271 return err;
272}
273
274int __init nsproxy_cache_init(void)
275{
276 nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);
277 return 0;
278}