1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright 2008 Red Hat, Inc. All rights reserved.
4 * Copyright 2008 Ian Kent <raven@themaw.net>
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(to: &tmp, from: in, AUTOFS_DEV_IOCTL_SIZE))
87 return ERR_PTR(error: -EFAULT);
88
89 if (tmp.size < AUTOFS_DEV_IOCTL_SIZE)
90 return ERR_PTR(error: -EINVAL);
91
92 if (tmp.size > AUTOFS_DEV_IOCTL_SIZE + PATH_MAX)
93 return ERR_PTR(error: -ENAMETOOLONG);
94
95 res = memdup_user(in, tmp.size);
96 if (!IS_ERR(ptr: 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(objp: 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(str: param->path, size: 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(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(dentry: 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 int err, fd;
235
236 fd = get_unused_fd_flags(O_CLOEXEC);
237 if (likely(fd >= 0)) {
238 struct file *filp;
239 struct path path;
240
241 err = find_autofs_mount(pathname: name, res: &path, test: test_by_dev, data: &devid);
242 if (err)
243 goto out;
244
245 filp = dentry_open(path: &path, O_RDONLY, current_cred());
246 path_put(&path);
247 if (IS_ERR(ptr: filp)) {
248 err = PTR_ERR(ptr: filp);
249 goto out;
250 }
251
252 fd_install(fd, file: filp);
253 }
254
255 return fd;
256
257out:
258 put_unused_fd(fd);
259 return err;
260}
261
262/* Open a file descriptor on an autofs mount point */
263static int autofs_dev_ioctl_openmount(struct file *fp,
264 struct autofs_sb_info *sbi,
265 struct autofs_dev_ioctl *param)
266{
267 const char *path;
268 dev_t devid;
269 int err, fd;
270
271 /* param->path has been checked in validate_dev_ioctl() */
272
273 if (!param->openmount.devid)
274 return -EINVAL;
275
276 param->ioctlfd = -1;
277
278 path = param->path;
279 devid = new_decode_dev(dev: param->openmount.devid);
280
281 err = 0;
282 fd = autofs_dev_ioctl_open_mountpoint(name: path, devid);
283 if (unlikely(fd < 0)) {
284 err = fd;
285 goto out;
286 }
287
288 param->ioctlfd = fd;
289out:
290 return err;
291}
292
293/* Close file descriptor allocated above (user can also use close(2)). */
294static int autofs_dev_ioctl_closemount(struct file *fp,
295 struct autofs_sb_info *sbi,
296 struct autofs_dev_ioctl *param)
297{
298 return close_fd(fd: param->ioctlfd);
299}
300
301/*
302 * Send "ready" status for an existing wait (either a mount or an expire
303 * request).
304 */
305static int autofs_dev_ioctl_ready(struct file *fp,
306 struct autofs_sb_info *sbi,
307 struct autofs_dev_ioctl *param)
308{
309 autofs_wqt_t token;
310
311 token = (autofs_wqt_t) param->ready.token;
312 return autofs_wait_release(sbi, token, 0);
313}
314
315/*
316 * Send "fail" status for an existing wait (either a mount or an expire
317 * request).
318 */
319static int autofs_dev_ioctl_fail(struct file *fp,
320 struct autofs_sb_info *sbi,
321 struct autofs_dev_ioctl *param)
322{
323 autofs_wqt_t token;
324 int status;
325
326 token = (autofs_wqt_t) param->fail.token;
327 status = param->fail.status < 0 ? param->fail.status : -ENOENT;
328 return autofs_wait_release(sbi, token, status);
329}
330
331/*
332 * Set the pipe fd for kernel communication to the daemon.
333 *
334 * Normally this is set at mount using an option but if we
335 * are reconnecting to a busy mount then we need to use this
336 * to tell the autofs mount about the new kernel pipe fd. In
337 * order to protect mounts against incorrectly setting the
338 * pipefd we also require that the autofs mount be catatonic.
339 *
340 * This also sets the process group id used to identify the
341 * controlling process (eg. the owning automount(8) daemon).
342 */
343static int autofs_dev_ioctl_setpipefd(struct file *fp,
344 struct autofs_sb_info *sbi,
345 struct autofs_dev_ioctl *param)
346{
347 int pipefd;
348 int err = 0;
349 struct pid *new_pid = NULL;
350
351 if (param->setpipefd.pipefd == -1)
352 return -EINVAL;
353
354 pipefd = param->setpipefd.pipefd;
355
356 mutex_lock(lock: &sbi->wq_mutex);
357 if (!(sbi->flags & AUTOFS_SBI_CATATONIC)) {
358 mutex_unlock(lock: &sbi->wq_mutex);
359 return -EBUSY;
360 } else {
361 struct file *pipe;
362
363 new_pid = get_task_pid(current, type: PIDTYPE_PGID);
364
365 if (ns_of_pid(pid: new_pid) != ns_of_pid(pid: sbi->oz_pgrp)) {
366 pr_warn("not allowed to change PID namespace\n");
367 err = -EINVAL;
368 goto out;
369 }
370
371 pipe = fget(fd: pipefd);
372 if (!pipe) {
373 err = -EBADF;
374 goto out;
375 }
376 if (autofs_prepare_pipe(pipe) < 0) {
377 err = -EPIPE;
378 fput(pipe);
379 goto out;
380 }
381 swap(sbi->oz_pgrp, new_pid);
382 sbi->pipefd = pipefd;
383 sbi->pipe = pipe;
384 sbi->flags &= ~AUTOFS_SBI_CATATONIC;
385 }
386out:
387 put_pid(pid: new_pid);
388 mutex_unlock(lock: &sbi->wq_mutex);
389 return err;
390}
391
392/*
393 * Make the autofs mount point catatonic, no longer responsive to
394 * mount requests. Also closes the kernel pipe file descriptor.
395 */
396static int autofs_dev_ioctl_catatonic(struct file *fp,
397 struct autofs_sb_info *sbi,
398 struct autofs_dev_ioctl *param)
399{
400 autofs_catatonic_mode(sbi);
401 return 0;
402}
403
404/*
405 * Set the autofs mount expire timeout.
406 *
407 * There are two places an expire timeout can be set, in the autofs
408 * super block info. (this is all that's needed for direct and offset
409 * mounts because there's a distinct mount corresponding to each of
410 * these) and per-dentry within within the dentry info. If a per-dentry
411 * timeout is set it will override the expire timeout set in the parent
412 * autofs super block info.
413 *
414 * If setting the autofs super block expire timeout the autofs_dev_ioctl
415 * size field will be equal to the autofs_dev_ioctl structure size. If
416 * setting the per-dentry expire timeout the mount point name is passed
417 * in the autofs_dev_ioctl path field and the size field updated to
418 * reflect this.
419 *
420 * Setting the autofs mount expire timeout sets the timeout in the super
421 * block info. struct. Setting the per-dentry timeout does a little more.
422 * If the timeout is equal to -1 the per-dentry timeout (and flag) is
423 * cleared which reverts to using the super block timeout, otherwise if
424 * timeout is 0 the timeout is set to this value and the flag is left
425 * set which disables expiration for the mount point, lastly the flag
426 * and the timeout are set enabling the dentry to use this timeout.
427 */
428static int autofs_dev_ioctl_timeout(struct file *fp,
429 struct autofs_sb_info *sbi,
430 struct autofs_dev_ioctl *param)
431{
432 unsigned long timeout = param->timeout.timeout;
433
434 /* If setting the expire timeout for an individual indirect
435 * mount point dentry the mount trailing component path is
436 * placed in param->path and param->size adjusted to account
437 * for it otherwise param->size it is set to the structure
438 * size.
439 */
440 if (param->size == AUTOFS_DEV_IOCTL_SIZE) {
441 param->timeout.timeout = sbi->exp_timeout / HZ;
442 sbi->exp_timeout = timeout * HZ;
443 } else {
444 struct dentry *base = fp->f_path.dentry;
445 int path_len = param->size - AUTOFS_DEV_IOCTL_SIZE - 1;
446 struct dentry *dentry;
447 struct autofs_info *ino;
448
449 if (!autofs_type_indirect(type: sbi->type))
450 return -EINVAL;
451
452 /* An expire timeout greater than the superblock timeout
453 * could be a problem at shutdown but the super block
454 * timeout itself can change so all we can really do is
455 * warn the user.
456 */
457 if (timeout >= sbi->exp_timeout)
458 pr_warn("per-mount expire timeout is greater than "
459 "the parent autofs mount timeout which could "
460 "prevent shutdown\n");
461
462 dentry = try_lookup_noperm(&QSTR_LEN(param->path, path_len),
463 base);
464 if (IS_ERR_OR_NULL(ptr: dentry))
465 return dentry ? PTR_ERR(ptr: dentry) : -ENOENT;
466 ino = autofs_dentry_ino(dentry);
467 if (!ino) {
468 dput(dentry);
469 return -ENOENT;
470 }
471
472 if (ino->exp_timeout && ino->flags & AUTOFS_INF_EXPIRE_SET)
473 param->timeout.timeout = ino->exp_timeout / HZ;
474 else
475 param->timeout.timeout = sbi->exp_timeout / HZ;
476
477 if (timeout == -1) {
478 /* Revert to using the super block timeout */
479 ino->flags &= ~AUTOFS_INF_EXPIRE_SET;
480 ino->exp_timeout = 0;
481 } else {
482 /* Set the dentry expire flag and timeout.
483 *
484 * If timeout is 0 it will prevent the expire
485 * of this particular automount.
486 */
487 ino->flags |= AUTOFS_INF_EXPIRE_SET;
488 ino->exp_timeout = timeout * HZ;
489 }
490 dput(dentry);
491 }
492
493 return 0;
494}
495
496/*
497 * Return the uid and gid of the last request for the mount
498 *
499 * When reconstructing an autofs mount tree with active mounts
500 * we need to re-connect to mounts that may have used the original
501 * process uid and gid (or string variations of them) for mount
502 * lookups within the map entry.
503 */
504static int autofs_dev_ioctl_requester(struct file *fp,
505 struct autofs_sb_info *sbi,
506 struct autofs_dev_ioctl *param)
507{
508 struct autofs_info *ino;
509 struct path path;
510 dev_t devid;
511 int err = -ENOENT;
512
513 /* param->path has been checked in validate_dev_ioctl() */
514
515 devid = sbi->sb->s_dev;
516
517 param->requester.uid = param->requester.gid = -1;
518
519 err = find_autofs_mount(pathname: param->path, res: &path, test: test_by_dev, data: &devid);
520 if (err)
521 goto out;
522
523 ino = autofs_dentry_ino(dentry: path.dentry);
524 if (ino) {
525 err = 0;
526 autofs_expire_wait(path: &path, rcu_walk: 0);
527 spin_lock(lock: &sbi->fs_lock);
528 param->requester.uid =
529 from_kuid_munged(to: current_user_ns(), kuid: ino->uid);
530 param->requester.gid =
531 from_kgid_munged(to: current_user_ns(), kgid: ino->gid);
532 spin_unlock(lock: &sbi->fs_lock);
533 }
534 path_put(&path);
535out:
536 return err;
537}
538
539/*
540 * Call repeatedly until it returns -EAGAIN, meaning there's nothing
541 * more that can be done.
542 */
543static int autofs_dev_ioctl_expire(struct file *fp,
544 struct autofs_sb_info *sbi,
545 struct autofs_dev_ioctl *param)
546{
547 struct vfsmount *mnt;
548 int how;
549
550 how = param->expire.how;
551 mnt = fp->f_path.mnt;
552
553 return autofs_do_expire_multi(sb: sbi->sb, mnt, sbi, how);
554}
555
556/* Check if autofs mount point is in use */
557static int autofs_dev_ioctl_askumount(struct file *fp,
558 struct autofs_sb_info *sbi,
559 struct autofs_dev_ioctl *param)
560{
561 param->askumount.may_umount = 0;
562 if (may_umount(fp->f_path.mnt))
563 param->askumount.may_umount = 1;
564 return 0;
565}
566
567/*
568 * Check if the given path is a mountpoint.
569 *
570 * If we are supplied with the file descriptor of an autofs
571 * mount we're looking for a specific mount. In this case
572 * the path is considered a mountpoint if it is itself a
573 * mountpoint or contains a mount, such as a multi-mount
574 * without a root mount. In this case we return 1 if the
575 * path is a mount point and the super magic of the covering
576 * mount if there is one or 0 if it isn't a mountpoint.
577 *
578 * If we aren't supplied with a file descriptor then we
579 * lookup the path and check if it is the root of a mount.
580 * If a type is given we are looking for a particular autofs
581 * mount and if we don't find a match we return fail. If the
582 * located path is the root of a mount we return 1 along with
583 * the super magic of the mount or 0 otherwise.
584 *
585 * In both cases the device number (as returned by
586 * new_encode_dev()) is also returned.
587 */
588static int autofs_dev_ioctl_ismountpoint(struct file *fp,
589 struct autofs_sb_info *sbi,
590 struct autofs_dev_ioctl *param)
591{
592 struct path path;
593 const char *name;
594 unsigned int type;
595 unsigned int devid, magic;
596 int err = -ENOENT;
597
598 /* param->path has been checked in validate_dev_ioctl() */
599
600 name = param->path;
601 type = param->ismountpoint.in.type;
602
603 param->ismountpoint.out.devid = devid = 0;
604 param->ismountpoint.out.magic = magic = 0;
605
606 if (!fp || param->ioctlfd == -1) {
607 if (autofs_type_any(type))
608 err = kern_path(name, LOOKUP_FOLLOW | LOOKUP_MOUNTPOINT,
609 &path);
610 else
611 err = find_autofs_mount(pathname: name, res: &path,
612 test: test_by_type, data: &type);
613 if (err)
614 goto out;
615 devid = new_encode_dev(dev: path.dentry->d_sb->s_dev);
616 err = 0;
617 if (path.mnt->mnt_root == path.dentry) {
618 err = 1;
619 magic = path.dentry->d_sb->s_magic;
620 }
621 } else {
622 dev_t dev = sbi->sb->s_dev;
623
624 err = find_autofs_mount(pathname: name, res: &path, test: test_by_dev, data: &dev);
625 if (err)
626 goto out;
627
628 devid = new_encode_dev(dev);
629
630 err = path_has_submounts(&path);
631
632 if (follow_down_one(&path))
633 magic = path.dentry->d_sb->s_magic;
634 }
635
636 param->ismountpoint.out.devid = devid;
637 param->ismountpoint.out.magic = magic;
638 path_put(&path);
639out:
640 return err;
641}
642
643/*
644 * Our range of ioctl numbers isn't 0 based so we need to shift
645 * the array index by _IOC_NR(AUTOFS_CTL_IOC_FIRST) for the table
646 * lookup.
647 */
648#define cmd_idx(cmd) (cmd - _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST))
649
650static ioctl_fn lookup_dev_ioctl(unsigned int cmd)
651{
652 static const ioctl_fn _ioctls[] = {
653 autofs_dev_ioctl_version,
654 autofs_dev_ioctl_protover,
655 autofs_dev_ioctl_protosubver,
656 autofs_dev_ioctl_openmount,
657 autofs_dev_ioctl_closemount,
658 autofs_dev_ioctl_ready,
659 autofs_dev_ioctl_fail,
660 autofs_dev_ioctl_setpipefd,
661 autofs_dev_ioctl_catatonic,
662 autofs_dev_ioctl_timeout,
663 autofs_dev_ioctl_requester,
664 autofs_dev_ioctl_expire,
665 autofs_dev_ioctl_askumount,
666 autofs_dev_ioctl_ismountpoint,
667 };
668 unsigned int idx = cmd_idx(cmd);
669
670 if (idx >= ARRAY_SIZE(_ioctls))
671 return NULL;
672 idx = array_index_nospec(idx, ARRAY_SIZE(_ioctls));
673 return _ioctls[idx];
674}
675
676/* ioctl dispatcher */
677static int _autofs_dev_ioctl(unsigned int command,
678 struct autofs_dev_ioctl __user *user)
679{
680 struct autofs_dev_ioctl *param;
681 struct file *fp;
682 struct autofs_sb_info *sbi;
683 unsigned int cmd_first, cmd;
684 ioctl_fn fn = NULL;
685 int err = 0;
686
687 cmd_first = _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST);
688 cmd = _IOC_NR(command);
689
690 if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) ||
691 cmd - cmd_first > AUTOFS_DEV_IOCTL_IOC_COUNT) {
692 return -ENOTTY;
693 }
694
695 /* Only root can use ioctls other than AUTOFS_DEV_IOCTL_VERSION_CMD
696 * and AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD
697 */
698 if (cmd != AUTOFS_DEV_IOCTL_VERSION_CMD &&
699 cmd != AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD &&
700 !capable(CAP_SYS_ADMIN))
701 return -EPERM;
702
703 /* Copy the parameters into kernel space. */
704 param = copy_dev_ioctl(in: user);
705 if (IS_ERR(ptr: param))
706 return PTR_ERR(ptr: param);
707
708 err = validate_dev_ioctl(cmd: command, param);
709 if (err)
710 goto out;
711
712 fn = lookup_dev_ioctl(cmd);
713 if (!fn) {
714 pr_warn("unknown command 0x%08x\n", command);
715 err = -ENOTTY;
716 goto out;
717 }
718
719 fp = NULL;
720 sbi = NULL;
721
722 /*
723 * For obvious reasons the openmount can't have a file
724 * descriptor yet. We don't take a reference to the
725 * file during close to allow for immediate release,
726 * and the same for retrieving ioctl version.
727 */
728 if (cmd != AUTOFS_DEV_IOCTL_VERSION_CMD &&
729 cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD &&
730 cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) {
731 struct super_block *sb;
732
733 fp = fget(fd: param->ioctlfd);
734 if (!fp) {
735 if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD)
736 goto cont;
737 err = -EBADF;
738 goto out;
739 }
740
741 sb = file_inode(f: fp)->i_sb;
742 if (sb->s_type != &autofs_fs_type) {
743 err = -EINVAL;
744 fput(fp);
745 goto out;
746 }
747 sbi = autofs_sbi(sb);
748
749 /*
750 * Admin needs to be able to set the mount catatonic in
751 * order to be able to perform the re-open.
752 */
753 if (!autofs_oz_mode(sbi) &&
754 cmd != AUTOFS_DEV_IOCTL_CATATONIC_CMD) {
755 err = -EACCES;
756 fput(fp);
757 goto out;
758 }
759 }
760cont:
761 err = fn(fp, sbi, param);
762
763 if (fp)
764 fput(fp);
765 if (err >= 0 && copy_to_user(to: user, from: param, AUTOFS_DEV_IOCTL_SIZE))
766 err = -EFAULT;
767out:
768 free_dev_ioctl(param);
769 return err;
770}
771
772static long autofs_dev_ioctl(struct file *file, unsigned int command,
773 unsigned long u)
774{
775 int err;
776
777 err = _autofs_dev_ioctl(command, user: (struct autofs_dev_ioctl __user *) u);
778 return (long) err;
779}
780
781#ifdef CONFIG_COMPAT
782static long autofs_dev_ioctl_compat(struct file *file, unsigned int command,
783 unsigned long u)
784{
785 return autofs_dev_ioctl(file, command, u: (unsigned long) compat_ptr(uptr: u));
786}
787#else
788#define autofs_dev_ioctl_compat NULL
789#endif
790
791static const struct file_operations _dev_ioctl_fops = {
792 .unlocked_ioctl = autofs_dev_ioctl,
793 .compat_ioctl = autofs_dev_ioctl_compat,
794 .owner = THIS_MODULE,
795 .llseek = noop_llseek,
796};
797
798static struct miscdevice _autofs_dev_ioctl_misc = {
799 .minor = AUTOFS_MINOR,
800 .name = AUTOFS_DEVICE_NAME,
801 .fops = &_dev_ioctl_fops,
802 .mode = 0644,
803};
804
805MODULE_ALIAS_MISCDEV(AUTOFS_MINOR);
806MODULE_ALIAS("devname:autofs");
807
808/* Register/deregister misc character device */
809int __init autofs_dev_ioctl_init(void)
810{
811 int r;
812
813 r = misc_register(misc: &_autofs_dev_ioctl_misc);
814 if (r) {
815 pr_err("misc_register failed for control device\n");
816 return r;
817 }
818
819 return 0;
820}
821
822void autofs_dev_ioctl_exit(void)
823{
824 misc_deregister(misc: &_autofs_dev_ioctl_misc);
825}
826