Line data Source code
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 :
30 : static struct kmem_cache *nsproxy_cachep;
31 :
32 : struct 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 :
52 50 : static inline struct nsproxy *create_nsproxy(void)
53 : {
54 50 : struct nsproxy *nsproxy;
55 :
56 50 : nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
57 50 : if (nsproxy)
58 50 : atomic_set(&nsproxy->count, 1);
59 50 : 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 : */
67 50 : static 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 50 : struct nsproxy *new_nsp;
72 50 : int err;
73 :
74 50 : new_nsp = create_nsproxy();
75 50 : if (!new_nsp)
76 50 : return ERR_PTR(-ENOMEM);
77 :
78 50 : new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, user_ns, new_fs);
79 50 : if (IS_ERR(new_nsp->mnt_ns)) {
80 0 : err = PTR_ERR(new_nsp->mnt_ns);
81 0 : goto out_ns;
82 : }
83 :
84 50 : new_nsp->uts_ns = copy_utsname(flags, user_ns, tsk->nsproxy->uts_ns);
85 50 : if (IS_ERR(new_nsp->uts_ns)) {
86 0 : err = PTR_ERR(new_nsp->uts_ns);
87 0 : goto out_uts;
88 : }
89 :
90 50 : new_nsp->ipc_ns = copy_ipcs(flags, user_ns, tsk->nsproxy->ipc_ns);
91 50 : if (IS_ERR(new_nsp->ipc_ns)) {
92 0 : err = PTR_ERR(new_nsp->ipc_ns);
93 0 : goto out_ipc;
94 : }
95 :
96 100 : new_nsp->pid_ns_for_children =
97 50 : copy_pid_ns(flags, user_ns, tsk->nsproxy->pid_ns_for_children);
98 50 : if (IS_ERR(new_nsp->pid_ns_for_children)) {
99 0 : err = PTR_ERR(new_nsp->pid_ns_for_children);
100 0 : goto out_pid;
101 : }
102 :
103 100 : new_nsp->cgroup_ns = copy_cgroup_ns(flags, user_ns,
104 50 : tsk->nsproxy->cgroup_ns);
105 50 : if (IS_ERR(new_nsp->cgroup_ns)) {
106 0 : err = PTR_ERR(new_nsp->cgroup_ns);
107 0 : goto out_cgroup;
108 : }
109 :
110 50 : new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);
111 50 : if (IS_ERR(new_nsp->net_ns)) {
112 0 : err = PTR_ERR(new_nsp->net_ns);
113 0 : goto out_net;
114 : }
115 :
116 100 : new_nsp->time_ns_for_children = copy_time_ns(flags, user_ns,
117 50 : tsk->nsproxy->time_ns_for_children);
118 50 : if (IS_ERR(new_nsp->time_ns_for_children)) {
119 0 : err = PTR_ERR(new_nsp->time_ns_for_children);
120 0 : goto out_time;
121 : }
122 50 : new_nsp->time_ns = get_time_ns(tsk->nsproxy->time_ns);
123 :
124 50 : return new_nsp;
125 :
126 0 : out_time:
127 0 : put_net(new_nsp->net_ns);
128 0 : out_net:
129 0 : put_cgroup_ns(new_nsp->cgroup_ns);
130 0 : out_cgroup:
131 0 : if (new_nsp->pid_ns_for_children)
132 0 : put_pid_ns(new_nsp->pid_ns_for_children);
133 0 : out_pid:
134 0 : if (new_nsp->ipc_ns)
135 0 : put_ipc_ns(new_nsp->ipc_ns);
136 0 : out_ipc:
137 0 : if (new_nsp->uts_ns)
138 0 : put_uts_ns(new_nsp->uts_ns);
139 0 : out_uts:
140 0 : if (new_nsp->mnt_ns)
141 0 : put_mnt_ns(new_nsp->mnt_ns);
142 0 : out_ns:
143 0 : kmem_cache_free(nsproxy_cachep, new_nsp);
144 0 : return ERR_PTR(err);
145 : }
146 :
147 : /*
148 : * called from clone. This now handles copy for nsproxy and all
149 : * namespaces therein.
150 : */
151 958 : int copy_namespaces(unsigned long flags, struct task_struct *tsk)
152 : {
153 958 : struct nsproxy *old_ns = tsk->nsproxy;
154 1916 : struct user_namespace *user_ns = task_cred_xxx(tsk, user_ns);
155 958 : struct nsproxy *new_ns;
156 :
157 958 : if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
158 : CLONE_NEWPID | CLONE_NEWNET |
159 : CLONE_NEWCGROUP | CLONE_NEWTIME)))) {
160 958 : if (likely(old_ns->time_ns_for_children == old_ns->time_ns)) {
161 958 : get_nsproxy(old_ns);
162 958 : return 0;
163 : }
164 0 : } else if (!ns_capable(user_ns, CAP_SYS_ADMIN))
165 : return -EPERM;
166 :
167 : /*
168 : * CLONE_NEWIPC must detach from the undolist: after switching
169 : * to a new ipc namespace, the semaphore arrays from the old
170 : * namespace are unreachable. In clone parlance, CLONE_SYSVSEM
171 : * means share undolist with parent, so we must forbid using
172 : * it along with CLONE_NEWIPC.
173 : */
174 0 : if ((flags & (CLONE_NEWIPC | CLONE_SYSVSEM)) ==
175 : (CLONE_NEWIPC | CLONE_SYSVSEM))
176 : return -EINVAL;
177 :
178 0 : new_ns = create_new_namespaces(flags, tsk, user_ns, tsk->fs);
179 0 : if (IS_ERR(new_ns))
180 0 : return PTR_ERR(new_ns);
181 :
182 0 : timens_on_fork(new_ns, tsk);
183 :
184 0 : tsk->nsproxy = new_ns;
185 0 : return 0;
186 : }
187 :
188 47 : void free_nsproxy(struct nsproxy *ns)
189 : {
190 47 : if (ns->mnt_ns)
191 47 : put_mnt_ns(ns->mnt_ns);
192 47 : if (ns->uts_ns)
193 47 : put_uts_ns(ns->uts_ns);
194 47 : if (ns->ipc_ns)
195 47 : put_ipc_ns(ns->ipc_ns);
196 47 : if (ns->pid_ns_for_children)
197 47 : put_pid_ns(ns->pid_ns_for_children);
198 47 : if (ns->time_ns)
199 47 : put_time_ns(ns->time_ns);
200 47 : if (ns->time_ns_for_children)
201 47 : put_time_ns(ns->time_ns_for_children);
202 47 : put_cgroup_ns(ns->cgroup_ns);
203 47 : put_net(ns->net_ns);
204 47 : kmem_cache_free(nsproxy_cachep, ns);
205 47 : }
206 :
207 : /*
208 : * Called from unshare. Unshare all the namespaces part of nsproxy.
209 : * On success, returns the new nsproxy.
210 : */
211 50 : int unshare_nsproxy_namespaces(unsigned long unshare_flags,
212 : struct nsproxy **new_nsp, struct cred *new_cred, struct fs_struct *new_fs)
213 : {
214 50 : struct user_namespace *user_ns;
215 50 : int err = 0;
216 :
217 50 : if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
218 : CLONE_NEWNET | CLONE_NEWPID | CLONE_NEWCGROUP |
219 : CLONE_NEWTIME)))
220 : return 0;
221 :
222 50 : user_ns = new_cred ? new_cred->user_ns : current_user_ns();
223 50 : if (!ns_capable(user_ns, CAP_SYS_ADMIN))
224 : return -EPERM;
225 :
226 99 : *new_nsp = create_new_namespaces(unshare_flags, current, user_ns,
227 49 : new_fs ? new_fs : current->fs);
228 50 : if (IS_ERR(*new_nsp)) {
229 0 : err = PTR_ERR(*new_nsp);
230 0 : goto out;
231 : }
232 :
233 50 : out:
234 : return err;
235 : }
236 :
237 928 : void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)
238 : {
239 928 : struct nsproxy *ns;
240 :
241 928 : might_sleep();
242 :
243 928 : task_lock(p);
244 928 : ns = p->nsproxy;
245 928 : p->nsproxy = new;
246 928 : task_unlock(p);
247 :
248 928 : if (ns)
249 928 : put_nsproxy(ns);
250 928 : }
251 :
252 878 : void exit_task_namespaces(struct task_struct *p)
253 : {
254 878 : switch_task_namespaces(p, NULL);
255 878 : }
256 :
257 0 : static int check_setns_flags(unsigned long flags)
258 : {
259 0 : if (!flags || (flags & ~(CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
260 : CLONE_NEWNET | CLONE_NEWTIME | CLONE_NEWUSER |
261 : CLONE_NEWPID | CLONE_NEWCGROUP)))
262 : return -EINVAL;
263 :
264 : #ifndef CONFIG_USER_NS
265 0 : if (flags & CLONE_NEWUSER)
266 : return -EINVAL;
267 : #endif
268 : #ifndef CONFIG_PID_NS
269 0 : if (flags & CLONE_NEWPID)
270 : return -EINVAL;
271 : #endif
272 : #ifndef CONFIG_UTS_NS
273 0 : if (flags & CLONE_NEWUTS)
274 : return -EINVAL;
275 : #endif
276 : #ifndef CONFIG_IPC_NS
277 0 : if (flags & CLONE_NEWIPC)
278 : return -EINVAL;
279 : #endif
280 : #ifndef CONFIG_CGROUPS
281 : if (flags & CLONE_NEWCGROUP)
282 : return -EINVAL;
283 : #endif
284 : #ifndef CONFIG_NET_NS
285 0 : if (flags & CLONE_NEWNET)
286 : return -EINVAL;
287 : #endif
288 : #ifndef CONFIG_TIME_NS
289 0 : if (flags & CLONE_NEWTIME)
290 0 : return -EINVAL;
291 : #endif
292 :
293 : return 0;
294 : }
295 :
296 0 : static void put_nsset(struct nsset *nsset)
297 : {
298 0 : unsigned flags = nsset->flags;
299 :
300 0 : if (flags & CLONE_NEWUSER)
301 0 : put_cred(nsset_cred(nsset));
302 : /*
303 : * We only created a temporary copy if we attached to more than just
304 : * the mount namespace.
305 : */
306 0 : if (nsset->fs && (flags & CLONE_NEWNS) && (flags & ~CLONE_NEWNS))
307 0 : free_fs_struct(nsset->fs);
308 0 : if (nsset->nsproxy)
309 0 : free_nsproxy(nsset->nsproxy);
310 0 : }
311 :
312 0 : static int prepare_nsset(unsigned flags, struct nsset *nsset)
313 : {
314 0 : struct task_struct *me = current;
315 :
316 0 : nsset->nsproxy = create_new_namespaces(0, me, current_user_ns(), me->fs);
317 0 : if (IS_ERR(nsset->nsproxy))
318 0 : return PTR_ERR(nsset->nsproxy);
319 :
320 0 : if (flags & CLONE_NEWUSER)
321 0 : nsset->cred = prepare_creds();
322 : else
323 0 : nsset->cred = current_cred();
324 0 : if (!nsset->cred)
325 0 : goto out;
326 :
327 : /* Only create a temporary copy of fs_struct if we really need to. */
328 0 : if (flags == CLONE_NEWNS) {
329 0 : nsset->fs = me->fs;
330 0 : } else if (flags & CLONE_NEWNS) {
331 0 : nsset->fs = copy_fs_struct(me->fs);
332 0 : if (!nsset->fs)
333 0 : goto out;
334 : }
335 :
336 0 : nsset->flags = flags;
337 0 : return 0;
338 :
339 0 : out:
340 0 : put_nsset(nsset);
341 0 : return -ENOMEM;
342 : }
343 :
344 0 : static inline int validate_ns(struct nsset *nsset, struct ns_common *ns)
345 : {
346 0 : return ns->ops->install(nsset, ns);
347 : }
348 :
349 : /*
350 : * This is the inverse operation to unshare().
351 : * Ordering is equivalent to the standard ordering used everywhere else
352 : * during unshare and process creation. The switch to the new set of
353 : * namespaces occurs at the point of no return after installation of
354 : * all requested namespaces was successful in commit_nsset().
355 : */
356 0 : static int validate_nsset(struct nsset *nsset, struct pid *pid)
357 : {
358 0 : int ret = 0;
359 0 : unsigned flags = nsset->flags;
360 0 : struct user_namespace *user_ns = NULL;
361 0 : struct pid_namespace *pid_ns = NULL;
362 0 : struct nsproxy *nsp;
363 0 : struct task_struct *tsk;
364 :
365 : /* Take a "snapshot" of the target task's namespaces. */
366 0 : rcu_read_lock();
367 0 : tsk = pid_task(pid, PIDTYPE_PID);
368 0 : if (!tsk) {
369 0 : rcu_read_unlock();
370 0 : return -ESRCH;
371 : }
372 :
373 0 : if (!ptrace_may_access(tsk, PTRACE_MODE_READ_REALCREDS)) {
374 0 : rcu_read_unlock();
375 0 : return -EPERM;
376 : }
377 :
378 0 : task_lock(tsk);
379 0 : nsp = tsk->nsproxy;
380 0 : if (nsp)
381 0 : get_nsproxy(nsp);
382 0 : task_unlock(tsk);
383 0 : if (!nsp) {
384 0 : rcu_read_unlock();
385 0 : return -ESRCH;
386 : }
387 :
388 : #ifdef CONFIG_PID_NS
389 : if (flags & CLONE_NEWPID) {
390 : pid_ns = task_active_pid_ns(tsk);
391 : if (unlikely(!pid_ns)) {
392 : rcu_read_unlock();
393 : ret = -ESRCH;
394 : goto out;
395 : }
396 : get_pid_ns(pid_ns);
397 : }
398 : #endif
399 :
400 : #ifdef CONFIG_USER_NS
401 : if (flags & CLONE_NEWUSER)
402 : user_ns = get_user_ns(__task_cred(tsk)->user_ns);
403 : #endif
404 0 : rcu_read_unlock();
405 :
406 : /*
407 : * Install requested namespaces. The caller will have
408 : * verified earlier that the requested namespaces are
409 : * supported on this kernel. We don't report errors here
410 : * if a namespace is requested that isn't supported.
411 : */
412 : #ifdef CONFIG_USER_NS
413 : if (flags & CLONE_NEWUSER) {
414 : ret = validate_ns(nsset, &user_ns->ns);
415 : if (ret)
416 : goto out;
417 : }
418 : #endif
419 :
420 0 : if (flags & CLONE_NEWNS) {
421 0 : ret = validate_ns(nsset, from_mnt_ns(nsp->mnt_ns));
422 0 : if (ret)
423 0 : goto out;
424 : }
425 :
426 : #ifdef CONFIG_UTS_NS
427 : if (flags & CLONE_NEWUTS) {
428 : ret = validate_ns(nsset, &nsp->uts_ns->ns);
429 : if (ret)
430 : goto out;
431 : }
432 : #endif
433 :
434 : #ifdef CONFIG_IPC_NS
435 : if (flags & CLONE_NEWIPC) {
436 : ret = validate_ns(nsset, &nsp->ipc_ns->ns);
437 : if (ret)
438 : goto out;
439 : }
440 : #endif
441 :
442 : #ifdef CONFIG_PID_NS
443 : if (flags & CLONE_NEWPID) {
444 : ret = validate_ns(nsset, &pid_ns->ns);
445 : if (ret)
446 : goto out;
447 : }
448 : #endif
449 :
450 : #ifdef CONFIG_CGROUPS
451 0 : if (flags & CLONE_NEWCGROUP) {
452 0 : ret = validate_ns(nsset, &nsp->cgroup_ns->ns);
453 0 : if (ret)
454 0 : goto out;
455 : }
456 : #endif
457 :
458 : #ifdef CONFIG_NET_NS
459 : if (flags & CLONE_NEWNET) {
460 : ret = validate_ns(nsset, &nsp->net_ns->ns);
461 : if (ret)
462 : goto out;
463 : }
464 : #endif
465 :
466 : #ifdef CONFIG_TIME_NS
467 : if (flags & CLONE_NEWTIME) {
468 : ret = validate_ns(nsset, &nsp->time_ns->ns);
469 : if (ret)
470 : goto out;
471 : }
472 : #endif
473 :
474 0 : out:
475 0 : if (pid_ns)
476 0 : put_pid_ns(pid_ns);
477 0 : if (nsp)
478 0 : put_nsproxy(nsp);
479 0 : put_user_ns(user_ns);
480 :
481 0 : return ret;
482 : }
483 :
484 : /*
485 : * This is the point of no return. There are just a few namespaces
486 : * that do some actual work here and it's sufficiently minimal that
487 : * a separate ns_common operation seems unnecessary for now.
488 : * Unshare is doing the same thing. If we'll end up needing to do
489 : * more in a given namespace or a helper here is ultimately not
490 : * exported anymore a simple commit handler for each namespace
491 : * should be added to ns_common.
492 : */
493 0 : static void commit_nsset(struct nsset *nsset)
494 : {
495 0 : unsigned flags = nsset->flags;
496 0 : struct task_struct *me = current;
497 :
498 : #ifdef CONFIG_USER_NS
499 : if (flags & CLONE_NEWUSER) {
500 : /* transfer ownership */
501 : commit_creds(nsset_cred(nsset));
502 : nsset->cred = NULL;
503 : }
504 : #endif
505 :
506 : /* We only need to commit if we have used a temporary fs_struct. */
507 0 : if ((flags & CLONE_NEWNS) && (flags & ~CLONE_NEWNS)) {
508 0 : set_fs_root(me->fs, &nsset->fs->root);
509 0 : set_fs_pwd(me->fs, &nsset->fs->pwd);
510 : }
511 :
512 : #ifdef CONFIG_IPC_NS
513 : if (flags & CLONE_NEWIPC)
514 : exit_sem(me);
515 : #endif
516 :
517 : #ifdef CONFIG_TIME_NS
518 : if (flags & CLONE_NEWTIME)
519 : timens_commit(me, nsset->nsproxy->time_ns);
520 : #endif
521 :
522 : /* transfer ownership */
523 0 : switch_task_namespaces(me, nsset->nsproxy);
524 0 : nsset->nsproxy = NULL;
525 0 : }
526 :
527 0 : SYSCALL_DEFINE2(setns, int, fd, int, flags)
528 : {
529 0 : struct file *file;
530 0 : struct ns_common *ns = NULL;
531 0 : struct nsset nsset = {};
532 0 : int err = 0;
533 :
534 0 : file = fget(fd);
535 0 : if (!file)
536 : return -EBADF;
537 :
538 0 : if (proc_ns_file(file)) {
539 0 : ns = get_proc_ns(file_inode(file));
540 0 : if (flags && (ns->ops->type != flags))
541 0 : err = -EINVAL;
542 0 : flags = ns->ops->type;
543 0 : } else if (!IS_ERR(pidfd_pid(file))) {
544 0 : err = check_setns_flags(flags);
545 : } else {
546 : err = -EINVAL;
547 : }
548 0 : if (err)
549 0 : goto out;
550 :
551 0 : err = prepare_nsset(flags, &nsset);
552 0 : if (err)
553 0 : goto out;
554 :
555 0 : if (proc_ns_file(file))
556 0 : err = validate_ns(&nsset, ns);
557 : else
558 0 : err = validate_nsset(&nsset, file->private_data);
559 0 : if (!err) {
560 0 : commit_nsset(&nsset);
561 0 : perf_event_namespaces(current);
562 : }
563 0 : put_nsset(&nsset);
564 0 : out:
565 0 : fput(file);
566 0 : return err;
567 : }
568 :
569 1 : int __init nsproxy_cache_init(void)
570 : {
571 1 : nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);
572 1 : return 0;
573 : }
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