1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/mount.h>
3 #include <linux/pseudo_fs.h>
4 #include <linux/file.h>
5 #include <linux/fs.h>
6 #include <linux/proc_fs.h>
7 #include <linux/proc_ns.h>
8 #include <linux/magic.h>
9 #include <linux/ktime.h>
10 #include <linux/seq_file.h>
11 #include <linux/pid_namespace.h>
12 #include <linux/user_namespace.h>
13 #include <linux/nsfs.h>
14 #include <linux/uaccess.h>
15 #include <linux/mnt_namespace.h>
16 #include <linux/ipc_namespace.h>
17 #include <linux/time_namespace.h>
18 #include <linux/utsname.h>
19 #include <linux/exportfs.h>
20 #include <linux/nstree.h>
21 #include <net/net_namespace.h>
22
23 #include "mount.h"
24 #include "internal.h"
25
26 static struct vfsmount *nsfs_mnt;
27
28 static struct path nsfs_root_path = {};
29
nsfs_get_root(struct path * path)30 void nsfs_get_root(struct path *path)
31 {
32 *path = nsfs_root_path;
33 path_get(path);
34 }
35
36 static long ns_ioctl(struct file *filp, unsigned int ioctl,
37 unsigned long arg);
38 static const struct file_operations ns_file_operations = {
39 .unlocked_ioctl = ns_ioctl,
40 .compat_ioctl = compat_ptr_ioctl,
41 };
42
ns_dname(struct dentry * dentry,char * buffer,int buflen)43 static char *ns_dname(struct dentry *dentry, char *buffer, int buflen)
44 {
45 struct inode *inode = d_inode(dentry);
46 struct ns_common *ns = inode->i_private;
47 const struct proc_ns_operations *ns_ops = ns->ops;
48
49 return dynamic_dname(buffer, buflen, "%s:[%lu]",
50 ns_ops->name, inode->i_ino);
51 }
52
53 const struct dentry_operations ns_dentry_operations = {
54 .d_dname = ns_dname,
55 .d_prune = stashed_dentry_prune,
56 };
57
nsfs_evict(struct inode * inode)58 static void nsfs_evict(struct inode *inode)
59 {
60 struct ns_common *ns = inode->i_private;
61
62 __ns_ref_active_put(ns);
63 clear_inode(inode);
64 ns->ops->put(ns);
65 }
66
ns_get_path_cb(struct path * path,ns_get_path_helper_t * ns_get_cb,void * private_data)67 int ns_get_path_cb(struct path *path, ns_get_path_helper_t *ns_get_cb,
68 void *private_data)
69 {
70 struct ns_common *ns;
71
72 ns = ns_get_cb(private_data);
73 if (!ns)
74 return -ENOENT;
75
76 return path_from_stashed(&ns->stashed, nsfs_mnt, ns, path);
77 }
78
79 struct ns_get_path_task_args {
80 const struct proc_ns_operations *ns_ops;
81 struct task_struct *task;
82 };
83
ns_get_path_task(void * private_data)84 static struct ns_common *ns_get_path_task(void *private_data)
85 {
86 struct ns_get_path_task_args *args = private_data;
87
88 return args->ns_ops->get(args->task);
89 }
90
ns_get_path(struct path * path,struct task_struct * task,const struct proc_ns_operations * ns_ops)91 int ns_get_path(struct path *path, struct task_struct *task,
92 const struct proc_ns_operations *ns_ops)
93 {
94 struct ns_get_path_task_args args = {
95 .ns_ops = ns_ops,
96 .task = task,
97 };
98
99 return ns_get_path_cb(path, ns_get_path_task, &args);
100 }
101
open_namespace_file(struct ns_common * ns)102 struct file *open_namespace_file(struct ns_common *ns)
103 {
104 struct path path __free(path_put) = {};
105 int err;
106
107 /* call first to consume reference */
108 err = path_from_stashed(&ns->stashed, nsfs_mnt, ns, &path);
109 if (err < 0)
110 return ERR_PTR(err);
111
112 return dentry_open(&path, O_RDONLY, current_cred());
113 }
114
115 /**
116 * open_namespace - open a namespace
117 * @ns: the namespace to open
118 *
119 * This will consume a reference to @ns indendent of success or failure.
120 *
121 * Return: A file descriptor on success or a negative error code on failure.
122 */
open_namespace(struct ns_common * ns)123 int open_namespace(struct ns_common *ns)
124 {
125 struct path path __free(path_put) = {};
126 int err;
127
128 /* call first to consume reference */
129 err = path_from_stashed(&ns->stashed, nsfs_mnt, ns, &path);
130 if (err < 0)
131 return err;
132
133 return FD_ADD(O_CLOEXEC, dentry_open(&path, O_RDONLY, current_cred()));
134 }
135
open_related_ns(struct ns_common * ns,struct ns_common * (* get_ns)(struct ns_common * ns))136 int open_related_ns(struct ns_common *ns,
137 struct ns_common *(*get_ns)(struct ns_common *ns))
138 {
139 struct ns_common *relative;
140
141 relative = get_ns(ns);
142 if (IS_ERR(relative))
143 return PTR_ERR(relative);
144
145 return open_namespace(relative);
146 }
147 EXPORT_SYMBOL_GPL(open_related_ns);
148
copy_ns_info_to_user(const struct mnt_namespace * mnt_ns,struct mnt_ns_info __user * uinfo,size_t usize,struct mnt_ns_info * kinfo)149 static int copy_ns_info_to_user(const struct mnt_namespace *mnt_ns,
150 struct mnt_ns_info __user *uinfo, size_t usize,
151 struct mnt_ns_info *kinfo)
152 {
153 /*
154 * If userspace and the kernel have the same struct size it can just
155 * be copied. If userspace provides an older struct, only the bits that
156 * userspace knows about will be copied. If userspace provides a new
157 * struct, only the bits that the kernel knows aobut will be copied and
158 * the size value will be set to the size the kernel knows about.
159 */
160 kinfo->size = min(usize, sizeof(*kinfo));
161 kinfo->mnt_ns_id = mnt_ns->ns.ns_id;
162 kinfo->nr_mounts = READ_ONCE(mnt_ns->nr_mounts);
163 /* Subtract the root mount of the mount namespace. */
164 if (kinfo->nr_mounts)
165 kinfo->nr_mounts--;
166
167 if (copy_to_user(uinfo, kinfo, kinfo->size))
168 return -EFAULT;
169
170 return 0;
171 }
172
nsfs_ioctl_valid(unsigned int cmd)173 static bool nsfs_ioctl_valid(unsigned int cmd)
174 {
175 switch (cmd) {
176 case NS_GET_USERNS:
177 case NS_GET_PARENT:
178 case NS_GET_NSTYPE:
179 case NS_GET_OWNER_UID:
180 case NS_GET_MNTNS_ID:
181 case NS_GET_PID_FROM_PIDNS:
182 case NS_GET_TGID_FROM_PIDNS:
183 case NS_GET_PID_IN_PIDNS:
184 case NS_GET_TGID_IN_PIDNS:
185 case NS_GET_ID:
186 return true;
187 }
188
189 /* Extensible ioctls require some extra handling. */
190 switch (_IOC_NR(cmd)) {
191 case _IOC_NR(NS_MNT_GET_INFO):
192 return extensible_ioctl_valid(cmd, NS_MNT_GET_INFO, MNT_NS_INFO_SIZE_VER0);
193 case _IOC_NR(NS_MNT_GET_NEXT):
194 return extensible_ioctl_valid(cmd, NS_MNT_GET_NEXT, MNT_NS_INFO_SIZE_VER0);
195 case _IOC_NR(NS_MNT_GET_PREV):
196 return extensible_ioctl_valid(cmd, NS_MNT_GET_PREV, MNT_NS_INFO_SIZE_VER0);
197 }
198
199 return false;
200 }
201
may_use_nsfs_ioctl(unsigned int cmd)202 static bool may_use_nsfs_ioctl(unsigned int cmd)
203 {
204 switch (_IOC_NR(cmd)) {
205 case _IOC_NR(NS_MNT_GET_NEXT):
206 fallthrough;
207 case _IOC_NR(NS_MNT_GET_PREV):
208 return may_see_all_namespaces();
209 }
210 return true;
211 }
212
ns_ioctl(struct file * filp,unsigned int ioctl,unsigned long arg)213 static long ns_ioctl(struct file *filp, unsigned int ioctl,
214 unsigned long arg)
215 {
216 struct user_namespace *user_ns;
217 struct pid_namespace *pid_ns;
218 struct task_struct *tsk;
219 struct ns_common *ns;
220 struct mnt_namespace *mnt_ns;
221 bool previous = false;
222 uid_t __user *argp;
223 uid_t uid;
224 int ret;
225
226 if (!nsfs_ioctl_valid(ioctl))
227 return -ENOIOCTLCMD;
228 if (!may_use_nsfs_ioctl(ioctl))
229 return -EPERM;
230
231 ns = get_proc_ns(file_inode(filp));
232 switch (ioctl) {
233 case NS_GET_USERNS:
234 return open_related_ns(ns, ns_get_owner);
235 case NS_GET_PARENT:
236 if (!ns->ops->get_parent)
237 return -EINVAL;
238 return open_related_ns(ns, ns->ops->get_parent);
239 case NS_GET_NSTYPE:
240 return ns->ns_type;
241 case NS_GET_OWNER_UID:
242 if (ns->ns_type != CLONE_NEWUSER)
243 return -EINVAL;
244 user_ns = container_of(ns, struct user_namespace, ns);
245 argp = (uid_t __user *) arg;
246 uid = from_kuid_munged(current_user_ns(), user_ns->owner);
247 return put_user(uid, argp);
248 case NS_GET_PID_FROM_PIDNS:
249 fallthrough;
250 case NS_GET_TGID_FROM_PIDNS:
251 fallthrough;
252 case NS_GET_PID_IN_PIDNS:
253 fallthrough;
254 case NS_GET_TGID_IN_PIDNS: {
255 if (ns->ns_type != CLONE_NEWPID)
256 return -EINVAL;
257
258 ret = -ESRCH;
259 pid_ns = container_of(ns, struct pid_namespace, ns);
260
261 guard(rcu)();
262
263 if (ioctl == NS_GET_PID_IN_PIDNS ||
264 ioctl == NS_GET_TGID_IN_PIDNS)
265 tsk = find_task_by_vpid(arg);
266 else
267 tsk = find_task_by_pid_ns(arg, pid_ns);
268 if (!tsk)
269 break;
270
271 switch (ioctl) {
272 case NS_GET_PID_FROM_PIDNS:
273 ret = task_pid_vnr(tsk);
274 break;
275 case NS_GET_TGID_FROM_PIDNS:
276 ret = task_tgid_vnr(tsk);
277 break;
278 case NS_GET_PID_IN_PIDNS:
279 ret = task_pid_nr_ns(tsk, pid_ns);
280 break;
281 case NS_GET_TGID_IN_PIDNS:
282 ret = task_tgid_nr_ns(tsk, pid_ns);
283 break;
284 default:
285 ret = 0;
286 break;
287 }
288
289 if (!ret)
290 ret = -ESRCH;
291 return ret;
292 }
293 case NS_GET_MNTNS_ID:
294 if (ns->ns_type != CLONE_NEWNS)
295 return -EINVAL;
296 fallthrough;
297 case NS_GET_ID: {
298 __u64 __user *idp;
299 __u64 id;
300
301 idp = (__u64 __user *)arg;
302 id = ns->ns_id;
303 return put_user(id, idp);
304 }
305 }
306
307 /* extensible ioctls */
308 switch (_IOC_NR(ioctl)) {
309 case _IOC_NR(NS_MNT_GET_INFO): {
310 struct mnt_ns_info kinfo = {};
311 struct mnt_ns_info __user *uinfo = (struct mnt_ns_info __user *)arg;
312 size_t usize = _IOC_SIZE(ioctl);
313
314 if (ns->ns_type != CLONE_NEWNS)
315 return -EINVAL;
316
317 if (!uinfo)
318 return -EINVAL;
319
320 if (usize < MNT_NS_INFO_SIZE_VER0)
321 return -EINVAL;
322
323 return copy_ns_info_to_user(to_mnt_ns(ns), uinfo, usize, &kinfo);
324 }
325 case _IOC_NR(NS_MNT_GET_PREV):
326 previous = true;
327 fallthrough;
328 case _IOC_NR(NS_MNT_GET_NEXT): {
329 struct mnt_ns_info kinfo = {};
330 struct mnt_ns_info __user *uinfo = (struct mnt_ns_info __user *)arg;
331 struct path path __free(path_put) = {};
332 size_t usize = _IOC_SIZE(ioctl);
333
334 if (ns->ns_type != CLONE_NEWNS)
335 return -EINVAL;
336
337 if (usize < MNT_NS_INFO_SIZE_VER0)
338 return -EINVAL;
339
340 mnt_ns = get_sequential_mnt_ns(to_mnt_ns(ns), previous);
341 if (IS_ERR(mnt_ns))
342 return PTR_ERR(mnt_ns);
343
344 ns = to_ns_common(mnt_ns);
345 /* Transfer ownership of @mnt_ns reference to @path. */
346 ret = path_from_stashed(&ns->stashed, nsfs_mnt, ns, &path);
347 if (ret)
348 return ret;
349
350 FD_PREPARE(fdf, O_CLOEXEC, dentry_open(&path, O_RDONLY, current_cred()));
351 if (fdf.err)
352 return fdf.err;
353 /*
354 * If @uinfo is passed return all information about the
355 * mount namespace as well.
356 */
357 ret = copy_ns_info_to_user(to_mnt_ns(ns), uinfo, usize, &kinfo);
358 if (ret)
359 return ret;
360 ret = fd_publish(fdf);
361 break;
362 }
363 default:
364 ret = -ENOTTY;
365 }
366
367 return ret;
368 }
369
ns_get_name(char * buf,size_t size,struct task_struct * task,const struct proc_ns_operations * ns_ops)370 int ns_get_name(char *buf, size_t size, struct task_struct *task,
371 const struct proc_ns_operations *ns_ops)
372 {
373 struct ns_common *ns;
374 int res = -ENOENT;
375 const char *name;
376 ns = ns_ops->get(task);
377 if (ns) {
378 name = ns_ops->real_ns_name ? : ns_ops->name;
379 res = snprintf(buf, size, "%s:[%u]", name, ns->inum);
380 ns_ops->put(ns);
381 }
382 return res;
383 }
384
proc_ns_file(const struct file * file)385 bool proc_ns_file(const struct file *file)
386 {
387 return file->f_op == &ns_file_operations;
388 }
389
390 /**
391 * ns_match() - Returns true if current namespace matches dev/ino provided.
392 * @ns: current namespace
393 * @dev: dev_t from nsfs that will be matched against current nsfs
394 * @ino: ino_t from nsfs that will be matched against current nsfs
395 *
396 * Return: true if dev and ino matches the current nsfs.
397 */
ns_match(const struct ns_common * ns,dev_t dev,ino_t ino)398 bool ns_match(const struct ns_common *ns, dev_t dev, ino_t ino)
399 {
400 return (ns->inum == ino) && (nsfs_mnt->mnt_sb->s_dev == dev);
401 }
402
403
nsfs_show_path(struct seq_file * seq,struct dentry * dentry)404 static int nsfs_show_path(struct seq_file *seq, struct dentry *dentry)
405 {
406 struct inode *inode = d_inode(dentry);
407 const struct ns_common *ns = inode->i_private;
408 const struct proc_ns_operations *ns_ops = ns->ops;
409
410 seq_printf(seq, "%s:[%lu]", ns_ops->name, inode->i_ino);
411 return 0;
412 }
413
414 static const struct super_operations nsfs_ops = {
415 .statfs = simple_statfs,
416 .evict_inode = nsfs_evict,
417 .show_path = nsfs_show_path,
418 .drop_inode = inode_just_drop,
419 };
420
nsfs_init_inode(struct inode * inode,void * data)421 static int nsfs_init_inode(struct inode *inode, void *data)
422 {
423 struct ns_common *ns = data;
424
425 inode->i_private = data;
426 inode->i_mode |= S_IRUGO;
427 inode->i_fop = &ns_file_operations;
428 inode->i_ino = ns->inum;
429
430 /*
431 * Bring the namespace subtree back to life if we have to. This
432 * can happen when e.g., all processes using a network namespace
433 * and all namespace files or namespace file bind-mounts have
434 * died but there are still sockets pinning it. The SIOCGSKNS
435 * ioctl on such a socket will resurrect the relevant namespace
436 * subtree.
437 */
438 __ns_ref_active_get(ns);
439 return 0;
440 }
441
nsfs_put_data(void * data)442 static void nsfs_put_data(void *data)
443 {
444 struct ns_common *ns = data;
445 ns->ops->put(ns);
446 }
447
448 static const struct stashed_operations nsfs_stashed_ops = {
449 .init_inode = nsfs_init_inode,
450 .put_data = nsfs_put_data,
451 };
452
453 #define NSFS_FID_SIZE_U32_VER0 (NSFS_FILE_HANDLE_SIZE_VER0 / sizeof(u32))
454 #define NSFS_FID_SIZE_U32_LATEST (NSFS_FILE_HANDLE_SIZE_LATEST / sizeof(u32))
455
nsfs_encode_fh(struct inode * inode,u32 * fh,int * max_len,struct inode * parent)456 static int nsfs_encode_fh(struct inode *inode, u32 *fh, int *max_len,
457 struct inode *parent)
458 {
459 struct nsfs_file_handle *fid = (struct nsfs_file_handle *)fh;
460 struct ns_common *ns = inode->i_private;
461 int len = *max_len;
462
463 if (parent)
464 return FILEID_INVALID;
465
466 if (len < NSFS_FID_SIZE_U32_VER0) {
467 *max_len = NSFS_FID_SIZE_U32_LATEST;
468 return FILEID_INVALID;
469 } else if (len > NSFS_FID_SIZE_U32_LATEST) {
470 *max_len = NSFS_FID_SIZE_U32_LATEST;
471 }
472
473 fid->ns_id = ns->ns_id;
474 fid->ns_type = ns->ns_type;
475 fid->ns_inum = inode->i_ino;
476 return FILEID_NSFS;
477 }
478
is_current_namespace(struct ns_common * ns)479 bool is_current_namespace(struct ns_common *ns)
480 {
481 switch (ns->ns_type) {
482 #ifdef CONFIG_CGROUPS
483 case CLONE_NEWCGROUP:
484 return current_in_namespace(to_cg_ns(ns));
485 #endif
486 #ifdef CONFIG_IPC_NS
487 case CLONE_NEWIPC:
488 return current_in_namespace(to_ipc_ns(ns));
489 #endif
490 case CLONE_NEWNS:
491 return current_in_namespace(to_mnt_ns(ns));
492 #ifdef CONFIG_NET_NS
493 case CLONE_NEWNET:
494 return current_in_namespace(to_net_ns(ns));
495 #endif
496 #ifdef CONFIG_PID_NS
497 case CLONE_NEWPID:
498 return current_in_namespace(to_pid_ns(ns));
499 #endif
500 #ifdef CONFIG_TIME_NS
501 case CLONE_NEWTIME:
502 return current_in_namespace(to_time_ns(ns));
503 #endif
504 #ifdef CONFIG_USER_NS
505 case CLONE_NEWUSER:
506 return current_in_namespace(to_user_ns(ns));
507 #endif
508 #ifdef CONFIG_UTS_NS
509 case CLONE_NEWUTS:
510 return current_in_namespace(to_uts_ns(ns));
511 #endif
512 default:
513 VFS_WARN_ON_ONCE(true);
514 return false;
515 }
516 }
517
nsfs_fh_to_dentry(struct super_block * sb,struct fid * fh,int fh_len,int fh_type)518 static struct dentry *nsfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
519 int fh_len, int fh_type)
520 {
521 struct path path __free(path_put) = {};
522 struct nsfs_file_handle *fid = (struct nsfs_file_handle *)fh;
523 struct user_namespace *owning_ns = NULL;
524 struct ns_common *ns;
525 int ret;
526
527 if (fh_len < NSFS_FID_SIZE_U32_VER0)
528 return NULL;
529
530 /* Check that any trailing bytes are zero. */
531 if ((fh_len > NSFS_FID_SIZE_U32_LATEST) &&
532 memchr_inv((void *)fid + NSFS_FID_SIZE_U32_LATEST, 0,
533 fh_len - NSFS_FID_SIZE_U32_LATEST))
534 return NULL;
535
536 switch (fh_type) {
537 case FILEID_NSFS:
538 break;
539 default:
540 return NULL;
541 }
542
543 if (!fid->ns_id)
544 return NULL;
545 /* Either both are set or both are unset. */
546 if (!fid->ns_inum != !fid->ns_type)
547 return NULL;
548
549 scoped_guard(rcu) {
550 ns = ns_tree_lookup_rcu(fid->ns_id, fid->ns_type);
551 if (!ns)
552 return NULL;
553
554 VFS_WARN_ON_ONCE(ns->ns_id != fid->ns_id);
555
556 if (fid->ns_inum && (fid->ns_inum != ns->inum))
557 return NULL;
558 if (fid->ns_type && (fid->ns_type != ns->ns_type))
559 return NULL;
560
561 /*
562 * This is racy because we're not actually taking an
563 * active reference. IOW, it could happen that the
564 * namespace becomes inactive after this check.
565 * We don't care because nsfs_init_inode() will just
566 * resurrect the relevant namespace tree for us. If it
567 * has been active here we just allow it's resurrection.
568 * We could try to take an active reference here and
569 * then drop it again. But really, why bother.
570 */
571 if (!ns_get_unless_inactive(ns))
572 return NULL;
573 }
574
575 switch (ns->ns_type) {
576 #ifdef CONFIG_CGROUPS
577 case CLONE_NEWCGROUP:
578 if (!current_in_namespace(to_cg_ns(ns)))
579 owning_ns = to_cg_ns(ns)->user_ns;
580 break;
581 #endif
582 #ifdef CONFIG_IPC_NS
583 case CLONE_NEWIPC:
584 if (!current_in_namespace(to_ipc_ns(ns)))
585 owning_ns = to_ipc_ns(ns)->user_ns;
586 break;
587 #endif
588 case CLONE_NEWNS:
589 if (!current_in_namespace(to_mnt_ns(ns)))
590 owning_ns = to_mnt_ns(ns)->user_ns;
591 break;
592 #ifdef CONFIG_NET_NS
593 case CLONE_NEWNET:
594 if (!current_in_namespace(to_net_ns(ns)))
595 owning_ns = to_net_ns(ns)->user_ns;
596 break;
597 #endif
598 #ifdef CONFIG_PID_NS
599 case CLONE_NEWPID:
600 if (!current_in_namespace(to_pid_ns(ns))) {
601 owning_ns = to_pid_ns(ns)->user_ns;
602 } else if (!READ_ONCE(to_pid_ns(ns)->child_reaper)) {
603 ns->ops->put(ns);
604 return ERR_PTR(-EPERM);
605 }
606 break;
607 #endif
608 #ifdef CONFIG_TIME_NS
609 case CLONE_NEWTIME:
610 if (!current_in_namespace(to_time_ns(ns)))
611 owning_ns = to_time_ns(ns)->user_ns;
612 break;
613 #endif
614 #ifdef CONFIG_USER_NS
615 case CLONE_NEWUSER:
616 if (!current_in_namespace(to_user_ns(ns)))
617 owning_ns = to_user_ns(ns);
618 break;
619 #endif
620 #ifdef CONFIG_UTS_NS
621 case CLONE_NEWUTS:
622 if (!current_in_namespace(to_uts_ns(ns)))
623 owning_ns = to_uts_ns(ns)->user_ns;
624 break;
625 #endif
626 default:
627 return ERR_PTR(-EOPNOTSUPP);
628 }
629
630 if (owning_ns && !may_see_all_namespaces()) {
631 ns->ops->put(ns);
632 return ERR_PTR(-EPERM);
633 }
634
635 /* path_from_stashed() unconditionally consumes the reference. */
636 ret = path_from_stashed(&ns->stashed, nsfs_mnt, ns, &path);
637 if (ret)
638 return ERR_PTR(ret);
639
640 return no_free_ptr(path.dentry);
641 }
642
nsfs_export_permission(struct handle_to_path_ctx * ctx,unsigned int oflags)643 static int nsfs_export_permission(struct handle_to_path_ctx *ctx,
644 unsigned int oflags)
645 {
646 /* nsfs_fh_to_dentry() performs all permission checks. */
647 return 0;
648 }
649
nsfs_export_open(const struct path * path,unsigned int oflags)650 static struct file *nsfs_export_open(const struct path *path, unsigned int oflags)
651 {
652 return file_open_root(path, "", oflags, 0);
653 }
654
655 static const struct export_operations nsfs_export_operations = {
656 .encode_fh = nsfs_encode_fh,
657 .fh_to_dentry = nsfs_fh_to_dentry,
658 .open = nsfs_export_open,
659 .permission = nsfs_export_permission,
660 };
661
nsfs_init_fs_context(struct fs_context * fc)662 static int nsfs_init_fs_context(struct fs_context *fc)
663 {
664 struct pseudo_fs_context *ctx = init_pseudo(fc, NSFS_MAGIC);
665 if (!ctx)
666 return -ENOMEM;
667 fc->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
668 ctx->s_d_flags |= DCACHE_DONTCACHE;
669 ctx->ops = &nsfs_ops;
670 ctx->eops = &nsfs_export_operations;
671 ctx->dops = &ns_dentry_operations;
672 fc->s_fs_info = (void *)&nsfs_stashed_ops;
673 return 0;
674 }
675
676 static struct file_system_type nsfs = {
677 .name = "nsfs",
678 .init_fs_context = nsfs_init_fs_context,
679 .kill_sb = kill_anon_super,
680 };
681
nsfs_init(void)682 void __init nsfs_init(void)
683 {
684 nsfs_mnt = kern_mount(&nsfs);
685 if (IS_ERR(nsfs_mnt))
686 panic("can't set nsfs up\n");
687 nsfs_mnt->mnt_sb->s_flags &= ~SB_NOUSER;
688 nsfs_root_path.mnt = nsfs_mnt;
689 nsfs_root_path.dentry = nsfs_mnt->mnt_root;
690 }
691
nsproxy_ns_active_get(struct nsproxy * ns)692 void nsproxy_ns_active_get(struct nsproxy *ns)
693 {
694 ns_ref_active_get(ns->mnt_ns);
695 ns_ref_active_get(ns->uts_ns);
696 ns_ref_active_get(ns->ipc_ns);
697 ns_ref_active_get(ns->pid_ns_for_children);
698 ns_ref_active_get(ns->cgroup_ns);
699 ns_ref_active_get(ns->net_ns);
700 ns_ref_active_get(ns->time_ns);
701 ns_ref_active_get(ns->time_ns_for_children);
702 }
703
nsproxy_ns_active_put(struct nsproxy * ns)704 void nsproxy_ns_active_put(struct nsproxy *ns)
705 {
706 ns_ref_active_put(ns->mnt_ns);
707 ns_ref_active_put(ns->uts_ns);
708 ns_ref_active_put(ns->ipc_ns);
709 ns_ref_active_put(ns->pid_ns_for_children);
710 ns_ref_active_put(ns->cgroup_ns);
711 ns_ref_active_put(ns->net_ns);
712 ns_ref_active_put(ns->time_ns);
713 ns_ref_active_put(ns->time_ns_for_children);
714 }
715