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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright 2008 Red Hat, Inc. All rights reserved.
4 * Copyright 2008 Ian Kent <[email protected]>
5 */
6
7#include <linux/module.h>
8#include <linux/miscdevice.h>
9#include <linux/compat.h>
10#include <linux/fdtable.h>
11#include <linux/magic.h>
12#include <linux/nospec.h>
13
14#include "autofs_i.h"
15
16/*
17 * This module implements an interface for routing autofs ioctl control
18 * commands via a miscellaneous device file.
19 *
20 * The alternate interface is needed because we need to be able open
21 * an ioctl file descriptor on an autofs mount that may be covered by
22 * another mount. This situation arises when starting automount(8)
23 * or other user space daemon which uses direct mounts or offset
24 * mounts (used for autofs lazy mount/umount of nested mount trees),
25 * which have been left busy at service shutdown.
26 */
27
28typedef int (*ioctl_fn)(struct file *, struct autofs_sb_info *,
29 struct autofs_dev_ioctl *);
30
31static int check_name(const char *name)
32{
33 if (!strchr(name, '/'))
34 return -EINVAL;
35 return 0;
36}
37
38/*
39 * Check a string doesn't overrun the chunk of
40 * memory we copied from user land.
41 */
42static int invalid_str(char *str, size_t size)
43{
44 if (memchr(str, 0, size))
45 return 0;
46 return -EINVAL;
47}
48
49/*
50 * Check that the user compiled against correct version of autofs
51 * misc device code.
52 *
53 * As well as checking the version compatibility this always copies
54 * the kernel interface version out.
55 */
56static int check_dev_ioctl_version(int cmd, struct autofs_dev_ioctl *param)
57{
58 int err = 0;
59
60 if ((param->ver_major != AUTOFS_DEV_IOCTL_VERSION_MAJOR) ||
61 (param->ver_minor > AUTOFS_DEV_IOCTL_VERSION_MINOR)) {
62 pr_warn("ioctl control interface version mismatch: "
63 "kernel(%u.%u), user(%u.%u), cmd(0x%08x)\n",
64 AUTOFS_DEV_IOCTL_VERSION_MAJOR,
65 AUTOFS_DEV_IOCTL_VERSION_MINOR,
66 param->ver_major, param->ver_minor, cmd);
67 err = -EINVAL;
68 }
69
70 /* Fill in the kernel version. */
71 param->ver_major = AUTOFS_DEV_IOCTL_VERSION_MAJOR;
72 param->ver_minor = AUTOFS_DEV_IOCTL_VERSION_MINOR;
73
74 return err;
75}
76
77/*
78 * Copy parameter control struct, including a possible path allocated
79 * at the end of the struct.
80 */
81static struct autofs_dev_ioctl *
82copy_dev_ioctl(struct autofs_dev_ioctl __user *in)
83{
84 struct autofs_dev_ioctl tmp, *res;
85
86 if (copy_from_user(&tmp, in, AUTOFS_DEV_IOCTL_SIZE))
87 return ERR_PTR(-EFAULT);
88
89 if (tmp.size < AUTOFS_DEV_IOCTL_SIZE)
90 return ERR_PTR(-EINVAL);
91
92 if (tmp.size > AUTOFS_DEV_IOCTL_SIZE + PATH_MAX)
93 return ERR_PTR(-ENAMETOOLONG);
94
95 res = memdup_user(in, tmp.size);
96 if (!IS_ERR(res))
97 res->size = tmp.size;
98
99 return res;
100}
101
102static inline void free_dev_ioctl(struct autofs_dev_ioctl *param)
103{
104 kfree(param);
105}
106
107/*
108 * Check sanity of parameter control fields and if a path is present
109 * check that it is terminated and contains at least one "/".
110 */
111static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param)
112{
113 unsigned int inr = _IOC_NR(cmd);
114 int err;
115
116 err = check_dev_ioctl_version(cmd, param);
117 if (err) {
118 pr_warn("invalid device control module version "
119 "supplied for cmd(0x%08x)\n", cmd);
120 goto out;
121 }
122
123 if (param->size > AUTOFS_DEV_IOCTL_SIZE) {
124 err = invalid_str(param->path, param->size - AUTOFS_DEV_IOCTL_SIZE);
125 if (err) {
126 pr_warn(
127 "path string terminator missing for cmd(0x%08x)\n",
128 cmd);
129 goto out;
130 }
131
132 /* Setting the per-dentry expire timeout requires a trailing
133 * path component, ie. no '/', so invert the logic of the
134 * check_name() return for AUTOFS_DEV_IOCTL_TIMEOUT_CMD.
135 */
136 err = check_name(param->path);
137 if (inr == AUTOFS_DEV_IOCTL_TIMEOUT_CMD)
138 err = err ? 0 : -EINVAL;
139 if (err) {
140 pr_warn("invalid path supplied for cmd(0x%08x)\n",
141 cmd);
142 goto out;
143 }
144 } else {
145 if (inr == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD ||
146 inr == AUTOFS_DEV_IOCTL_REQUESTER_CMD ||
147 inr == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) {
148 err = -EINVAL;
149 goto out;
150 }
151 }
152
153 err = 0;
154out:
155 return err;
156}
157
158/* Return autofs dev ioctl version */
159static int autofs_dev_ioctl_version(struct file *fp,
160 struct autofs_sb_info *sbi,
161 struct autofs_dev_ioctl *param)
162{
163 /* This should have already been set. */
164 param->ver_major = AUTOFS_DEV_IOCTL_VERSION_MAJOR;
165 param->ver_minor = AUTOFS_DEV_IOCTL_VERSION_MINOR;
166 return 0;
167}
168
169/* Return autofs module protocol version */
170static int autofs_dev_ioctl_protover(struct file *fp,
171 struct autofs_sb_info *sbi,
172 struct autofs_dev_ioctl *param)
173{
174 param->protover.version = sbi->version;
175 return 0;
176}
177
178/* Return autofs module protocol sub version */
179static int autofs_dev_ioctl_protosubver(struct file *fp,
180 struct autofs_sb_info *sbi,
181 struct autofs_dev_ioctl *param)
182{
183 param->protosubver.sub_version = sbi->sub_version;
184 return 0;
185}
186
187/* Find the topmost mount satisfying test() */
188static int find_autofs_mount(const char *pathname,
189 struct path *res,
190 int test(const struct path *path, void *data),
191 void *data)
192{
193 struct path path;
194 int err;
195
196 err = kern_path(pathname, LOOKUP_MOUNTPOINT, &path);
197 if (err)
198 return err;
199 err = -ENOENT;
200 while (path.dentry == path.mnt->mnt_root) {
201 if (path.dentry->d_sb->s_magic == AUTOFS_SUPER_MAGIC) {
202 if (test(&path, data)) {
203 path_get(&path);
204 *res = path;
205 err = 0;
206 break;
207 }
208 }
209 if (!follow_up(&path))
210 break;
211 }
212 path_put(&path);
213 return err;
214}
215
216static int test_by_dev(const struct path *path, void *p)
217{
218 return path->dentry->d_sb->s_dev == *(dev_t *)p;
219}
220
221static int test_by_type(const struct path *path, void *p)
222{
223 struct autofs_info *ino = autofs_dentry_ino(path->dentry);
224
225 return ino && ino->sbi->type & *(unsigned *)p;
226}
227
228/*
229 * Open a file descriptor on the autofs mount point corresponding
230 * to the given path and device number (aka. new_encode_dev(sb->s_dev)).
231 */
232static int autofs_dev_ioctl_open_mountpoint(const char *name, dev_t devid)
233{
234 struct path path __free(path_put) = {};
235 int err;
236
237 err = find_autofs_mount(name, &path, test_by_dev, &devid);
238 if (err)
239 return err;
240
241 return FD_ADD(O_CLOEXEC, dentry_open(&path, O_RDONLY, current_cred()));
242}
243
244/* Open a file descriptor on an autofs mount point */
245static int autofs_dev_ioctl_openmount(struct file *fp,
246 struct autofs_sb_info *sbi,
247 struct autofs_dev_ioctl *param)
248{
249 const char *path;
250 dev_t devid;
251 int err, fd;
252
253 /* param->path has been checked in validate_dev_ioctl() */
254
255 if (!param->openmount.devid)
256 return -EINVAL;
257
258 param->ioctlfd = -1;
259
260 path = param->path;
261 devid = new_decode_dev(param->openmount.devid);
262
263 err = 0;
264 fd = autofs_dev_ioctl_open_mountpoint(path, devid);
265 if (unlikely(fd < 0)) {
266 err = fd;
267 goto out;
268 }
269
270 param->ioctlfd = fd;
271out:
272 return err;
273}
274
275/* Close file descriptor allocated above (user can also use close(2)). */
276static int autofs_dev_ioctl_closemount(struct file *fp,
277 struct autofs_sb_info *sbi,
278 struct autofs_dev_ioctl *param)
279{
280 return close_fd(param->ioctlfd);
281}
282
283/*
284 * Send "ready" status for an existing wait (either a mount or an expire
285 * request).
286 */
287static int autofs_dev_ioctl_ready(struct file *fp,
288 struct autofs_sb_info *sbi,
289 struct autofs_dev_ioctl *param)
290{
291 autofs_wqt_t token;
292
293 token = (autofs_wqt_t) param->ready.token;
294 return autofs_wait_release(sbi, token, 0);
295}
296
297/*
298 * Send "fail" status for an existing wait (either a mount or an expire
299 * request).
300 */
301static int autofs_dev_ioctl_fail(struct file *fp,
302 struct autofs_sb_info *sbi,
303 struct autofs_dev_ioctl *param)
304{
305 autofs_wqt_t token;
306 int status;
307
308 token = (autofs_wqt_t) param->fail.token;
309 status = param->fail.status < 0 ? param->fail.status : -ENOENT;
310 return autofs_wait_release(sbi, token, status);
311}
312
313/*
314 * Set the pipe fd for kernel communication to the daemon.
315 *
316 * Normally this is set at mount using an option but if we
317 * are reconnecting to a busy mount then we need to use this
318 * to tell the autofs mount about the new kernel pipe fd. In
319 * order to protect mounts against incorrectly setting the
320 * pipefd we also require that the autofs mount be catatonic.
321 *
322 * This also sets the process group id used to identify the
323 * controlling process (eg. the owning automount(8) daemon).
324 */
325static int autofs_dev_ioctl_setpipefd(struct file *fp,
326 struct autofs_sb_info *sbi,
327 struct autofs_dev_ioctl *param)
328{
329 int pipefd;
330 int err = 0;
331 struct pid *new_pid = NULL;
332
333 if (param->setpipefd.pipefd == -1)
334 return -EINVAL;
335
336 pipefd = param->setpipefd.pipefd;
337
338 mutex_lock(&sbi->wq_mutex);
339 if (!(sbi->flags & AUTOFS_SBI_CATATONIC)) {
340 mutex_unlock(&sbi->wq_mutex);
341 return -EBUSY;
342 } else {
343 struct file *pipe;
344
345 new_pid = get_task_pid(current, PIDTYPE_PGID);
346
347 if (ns_of_pid(new_pid) != ns_of_pid(sbi->oz_pgrp)) {
348 pr_warn("not allowed to change PID namespace\n");
349 err = -EINVAL;
350 goto out;
351 }
352
353 pipe = fget(pipefd);
354 if (!pipe) {
355 err = -EBADF;
356 goto out;
357 }
358 if (autofs_prepare_pipe(pipe) < 0) {
359 err = -EPIPE;
360 fput(pipe);
361 goto out;
362 }
363 swap(sbi->oz_pgrp, new_pid);
364 sbi->pipefd = pipefd;
365 sbi->pipe = pipe;
366 sbi->mnt_ns_id = to_ns_common(current->nsproxy->mnt_ns)->ns_id;
367 sbi->flags &= ~AUTOFS_SBI_CATATONIC;
368 }
369out:
370 put_pid(new_pid);
371 mutex_unlock(&sbi->wq_mutex);
372 return err;
373}
374
375/*
376 * Make the autofs mount point catatonic, no longer responsive to
377 * mount requests. Also closes the kernel pipe file descriptor.
378 */
379static int autofs_dev_ioctl_catatonic(struct file *fp,
380 struct autofs_sb_info *sbi,
381 struct autofs_dev_ioctl *param)
382{
383 autofs_catatonic_mode(sbi);
384 return 0;
385}
386
387/*
388 * Set the autofs mount expire timeout.
389 *
390 * There are two places an expire timeout can be set, in the autofs
391 * super block info. (this is all that's needed for direct and offset
392 * mounts because there's a distinct mount corresponding to each of
393 * these) and per-dentry within within the dentry info. If a per-dentry
394 * timeout is set it will override the expire timeout set in the parent
395 * autofs super block info.
396 *
397 * If setting the autofs super block expire timeout the autofs_dev_ioctl
398 * size field will be equal to the autofs_dev_ioctl structure size. If
399 * setting the per-dentry expire timeout the mount point name is passed
400 * in the autofs_dev_ioctl path field and the size field updated to
401 * reflect this.
402 *
403 * Setting the autofs mount expire timeout sets the timeout in the super
404 * block info. struct. Setting the per-dentry timeout does a little more.
405 * If the timeout is equal to -1 the per-dentry timeout (and flag) is
406 * cleared which reverts to using the super block timeout, otherwise if
407 * timeout is 0 the timeout is set to this value and the flag is left
408 * set which disables expiration for the mount point, lastly the flag
409 * and the timeout are set enabling the dentry to use this timeout.
410 */
411static int autofs_dev_ioctl_timeout(struct file *fp,
412 struct autofs_sb_info *sbi,
413 struct autofs_dev_ioctl *param)
414{
415 unsigned long timeout = param->timeout.timeout;
416
417 /* If setting the expire timeout for an individual indirect
418 * mount point dentry the mount trailing component path is
419 * placed in param->path and param->size adjusted to account
420 * for it otherwise param->size it is set to the structure
421 * size.
422 */
423 if (param->size == AUTOFS_DEV_IOCTL_SIZE) {
424 param->timeout.timeout = sbi->exp_timeout / HZ;
425 sbi->exp_timeout = timeout * HZ;
426 } else {
427 struct dentry *base = fp->f_path.dentry;
428 int path_len = param->size - AUTOFS_DEV_IOCTL_SIZE - 1;
429 struct dentry *dentry;
430 struct autofs_info *ino;
431
432 if (!autofs_type_indirect(sbi->type))
433 return -EINVAL;
434
435 dentry = try_lookup_noperm(&QSTR_LEN(param->path, path_len),
436 base);
437 if (IS_ERR_OR_NULL(dentry))
438 return dentry ? PTR_ERR(dentry) : -ENOENT;
439 ino = autofs_dentry_ino(dentry);
440 if (!ino) {
441 dput(dentry);
442 return -ENOENT;
443 }
444
445 if (ino->exp_timeout && ino->flags & AUTOFS_INF_EXPIRE_SET)
446 param->timeout.timeout = ino->exp_timeout / HZ;
447 else
448 param->timeout.timeout = sbi->exp_timeout / HZ;
449
450 if (timeout == -1) {
451 /* Revert to using the super block timeout */
452 ino->flags &= ~AUTOFS_INF_EXPIRE_SET;
453 ino->exp_timeout = 0;
454 } else {
455 /* Set the dentry expire flag and timeout.
456 *
457 * If timeout is 0 it will prevent the expire
458 * of this particular automount.
459 */
460 ino->flags |= AUTOFS_INF_EXPIRE_SET;
461 ino->exp_timeout = timeout * HZ;
462 }
463
464 /* An expire timeout greater than the superblock timeout
465 * could be a problem at shutdown but the super block
466 * timeout itself can change so all we can really do is
467 * warn the user.
468 */
469 if (ino->flags & AUTOFS_INF_EXPIRE_SET &&
470 ino->exp_timeout > sbi->exp_timeout)
471 pr_warn("per-mount expire timeout is greater than "
472 "the parent autofs mount timeout which could "
473 "prevent shutdown\n");
474
475 dput(dentry);
476 }
477
478 return 0;
479}
480
481/*
482 * Return the uid and gid of the last request for the mount
483 *
484 * When reconstructing an autofs mount tree with active mounts
485 * we need to re-connect to mounts that may have used the original
486 * process uid and gid (or string variations of them) for mount
487 * lookups within the map entry.
488 */
489static int autofs_dev_ioctl_requester(struct file *fp,
490 struct autofs_sb_info *sbi,
491 struct autofs_dev_ioctl *param)
492{
493 struct autofs_info *ino;
494 struct path path;
495 dev_t devid;
496 int err = -ENOENT;
497
498 /* param->path has been checked in validate_dev_ioctl() */
499
500 devid = sbi->sb->s_dev;
501
502 param->requester.uid = param->requester.gid = -1;
503
504 err = find_autofs_mount(param->path, &path, test_by_dev, &devid);
505 if (err)
506 goto out;
507
508 ino = autofs_dentry_ino(path.dentry);
509 if (ino) {
510 err = 0;
511 autofs_expire_wait(&path, 0);
512 spin_lock(&sbi->fs_lock);
513 param->requester.uid =
514 from_kuid_munged(current_user_ns(), ino->uid);
515 param->requester.gid =
516 from_kgid_munged(current_user_ns(), ino->gid);
517 spin_unlock(&sbi->fs_lock);
518 }
519 path_put(&path);
520out:
521 return err;
522}
523
524/*
525 * Call repeatedly until it returns -EAGAIN, meaning there's nothing
526 * more that can be done.
527 */
528static int autofs_dev_ioctl_expire(struct file *fp,
529 struct autofs_sb_info *sbi,
530 struct autofs_dev_ioctl *param)
531{
532 struct vfsmount *mnt;
533 int how;
534
535 how = param->expire.how;
536 mnt = fp->f_path.mnt;
537
538 return autofs_do_expire_multi(sbi->sb, mnt, sbi, how);
539}
540
541/* Check if autofs mount point is in use */
542static int autofs_dev_ioctl_askumount(struct file *fp,
543 struct autofs_sb_info *sbi,
544 struct autofs_dev_ioctl *param)
545{
546 param->askumount.may_umount = 0;
547 if (may_umount(fp->f_path.mnt))
548 param->askumount.may_umount = 1;
549 return 0;
550}
551
552/*
553 * Check if the given path is a mountpoint.
554 *
555 * If we are supplied with the file descriptor of an autofs
556 * mount we're looking for a specific mount. In this case
557 * the path is considered a mountpoint if it is itself a
558 * mountpoint or contains a mount, such as a multi-mount
559 * without a root mount. In this case we return 1 if the
560 * path is a mount point and the super magic of the covering
561 * mount if there is one or 0 if it isn't a mountpoint.
562 *
563 * If we aren't supplied with a file descriptor then we
564 * lookup the path and check if it is the root of a mount.
565 * If a type is given we are looking for a particular autofs
566 * mount and if we don't find a match we return fail. If the
567 * located path is the root of a mount we return 1 along with
568 * the super magic of the mount or 0 otherwise.
569 *
570 * In both cases the device number (as returned by
571 * new_encode_dev()) is also returned.
572 */
573static int autofs_dev_ioctl_ismountpoint(struct file *fp,
574 struct autofs_sb_info *sbi,
575 struct autofs_dev_ioctl *param)
576{
577 struct path path;
578 const char *name;
579 unsigned int type;
580 unsigned int devid, magic;
581 int err = -ENOENT;
582
583 /* param->path has been checked in validate_dev_ioctl() */
584
585 name = param->path;
586 type = param->ismountpoint.in.type;
587
588 param->ismountpoint.out.devid = devid = 0;
589 param->ismountpoint.out.magic = magic = 0;
590
591 if (!fp || param->ioctlfd == -1) {
592 if (autofs_type_any(type))
593 err = kern_path(name, LOOKUP_FOLLOW | LOOKUP_MOUNTPOINT,
594 &path);
595 else
596 err = find_autofs_mount(name, &path,
597 test_by_type, &type);
598 if (err)
599 goto out;
600 devid = new_encode_dev(path.dentry->d_sb->s_dev);
601 err = 0;
602 if (path.mnt->mnt_root == path.dentry) {
603 err = 1;
604 magic = path.dentry->d_sb->s_magic;
605 }
606 } else {
607 dev_t dev = sbi->sb->s_dev;
608
609 err = find_autofs_mount(name, &path, test_by_dev, &dev);
610 if (err)
611 goto out;
612
613 devid = new_encode_dev(dev);
614
615 err = path_has_submounts(&path);
616
617 if (follow_down_one(&path))
618 magic = path.dentry->d_sb->s_magic;
619 }
620
621 param->ismountpoint.out.devid = devid;
622 param->ismountpoint.out.magic = magic;
623 path_put(&path);
624out:
625 return err;
626}
627
628/*
629 * Our range of ioctl numbers isn't 0 based so we need to shift
630 * the array index by _IOC_NR(AUTOFS_CTL_IOC_FIRST) for the table
631 * lookup.
632 */
633#define cmd_idx(cmd) (cmd - _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST))
634
635static ioctl_fn lookup_dev_ioctl(unsigned int cmd)
636{
637 static const ioctl_fn _ioctls[] = {
638 autofs_dev_ioctl_version,
639 autofs_dev_ioctl_protover,
640 autofs_dev_ioctl_protosubver,
641 autofs_dev_ioctl_openmount,
642 autofs_dev_ioctl_closemount,
643 autofs_dev_ioctl_ready,
644 autofs_dev_ioctl_fail,
645 autofs_dev_ioctl_setpipefd,
646 autofs_dev_ioctl_catatonic,
647 autofs_dev_ioctl_timeout,
648 autofs_dev_ioctl_requester,
649 autofs_dev_ioctl_expire,
650 autofs_dev_ioctl_askumount,
651 autofs_dev_ioctl_ismountpoint,
652 };
653 unsigned int idx = cmd_idx(cmd);
654
655 if (idx >= ARRAY_SIZE(_ioctls))
656 return NULL;
657 idx = array_index_nospec(idx, ARRAY_SIZE(_ioctls));
658 return _ioctls[idx];
659}
660
661/* ioctl dispatcher */
662static int _autofs_dev_ioctl(unsigned int command,
663 struct autofs_dev_ioctl __user *user)
664{
665 struct autofs_dev_ioctl *param;
666 struct file *fp;
667 struct autofs_sb_info *sbi;
668 unsigned int cmd_first, cmd;
669 ioctl_fn fn = NULL;
670 int err = 0;
671
672 cmd_first = _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST);
673 cmd = _IOC_NR(command);
674
675 if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) ||
676 cmd - cmd_first > AUTOFS_DEV_IOCTL_IOC_COUNT) {
677 return -ENOTTY;
678 }
679
680 /* Only root can use ioctls other than AUTOFS_DEV_IOCTL_VERSION_CMD
681 * and AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD
682 */
683 if (cmd != AUTOFS_DEV_IOCTL_VERSION_CMD &&
684 cmd != AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD &&
685 !capable(CAP_SYS_ADMIN))
686 return -EPERM;
687
688 /* Copy the parameters into kernel space. */
689 param = copy_dev_ioctl(user);
690 if (IS_ERR(param))
691 return PTR_ERR(param);
692
693 err = validate_dev_ioctl(command, param);
694 if (err)
695 goto out;
696
697 fn = lookup_dev_ioctl(cmd);
698 if (!fn) {
699 pr_warn("unknown command 0x%08x\n", command);
700 err = -ENOTTY;
701 goto out;
702 }
703
704 fp = NULL;
705 sbi = NULL;
706
707 /*
708 * For obvious reasons the openmount can't have a file
709 * descriptor yet. We don't take a reference to the
710 * file during close to allow for immediate release,
711 * and the same for retrieving ioctl version.
712 */
713 if (cmd != AUTOFS_DEV_IOCTL_VERSION_CMD &&
714 cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD &&
715 cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) {
716 struct super_block *sb;
717
718 fp = fget(param->ioctlfd);
719 if (!fp) {
720 if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD)
721 goto cont;
722 err = -EBADF;
723 goto out;
724 }
725
726 sb = file_inode(fp)->i_sb;
727 if (sb->s_type != &autofs_fs_type) {
728 err = -EINVAL;
729 fput(fp);
730 goto out;
731 }
732 sbi = autofs_sbi(sb);
733
734 /*
735 * Admin needs to be able to set the mount catatonic in
736 * order to be able to perform the re-open.
737 */
738 if (!autofs_oz_mode(sbi) &&
739 cmd != AUTOFS_DEV_IOCTL_CATATONIC_CMD) {
740 err = -EACCES;
741 fput(fp);
742 goto out;
743 }
744 }
745cont:
746 err = fn(fp, sbi, param);
747
748 if (fp)
749 fput(fp);
750 if (err >= 0 && copy_to_user(user, param, AUTOFS_DEV_IOCTL_SIZE))
751 err = -EFAULT;
752out:
753 free_dev_ioctl(param);
754 return err;
755}
756
757static long autofs_dev_ioctl(struct file *file, unsigned int command,
758 unsigned long u)
759{
760 int err;
761
762 err = _autofs_dev_ioctl(command, (struct autofs_dev_ioctl __user *) u);
763 return (long) err;
764}
765
766#ifdef CONFIG_COMPAT
767static long autofs_dev_ioctl_compat(struct file *file, unsigned int command,
768 unsigned long u)
769{
770 return autofs_dev_ioctl(file, command, (unsigned long) compat_ptr(u));
771}
772#else
773#define autofs_dev_ioctl_compat NULL
774#endif
775
776static const struct file_operations _dev_ioctl_fops = {
777 .unlocked_ioctl = autofs_dev_ioctl,
778 .compat_ioctl = autofs_dev_ioctl_compat,
779 .owner = THIS_MODULE,
780 .llseek = noop_llseek,
781};
782
783static struct miscdevice _autofs_dev_ioctl_misc = {
784 .minor = AUTOFS_MINOR,
785 .name = AUTOFS_DEVICE_NAME,
786 .fops = &_dev_ioctl_fops,
787 .mode = 0644,
788};
789
790MODULE_ALIAS_MISCDEV(AUTOFS_MINOR);
791MODULE_ALIAS("devname:autofs");
792
793/* Register/deregister misc character device */
794int __init autofs_dev_ioctl_init(void)
795{
796 int r;
797
798 r = misc_register(&_autofs_dev_ioctl_misc);
799 if (r) {
800 pr_err("misc_register failed for control device\n");
801 return r;
802 }
803
804 return 0;
805}
806
807void autofs_dev_ioctl_exit(void)
808{
809 misc_deregister(&_autofs_dev_ioctl_misc);
810}