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 | |
28 | typedef int (*ioctl_fn)(struct file *, struct autofs_sb_info *, |
29 | struct autofs_dev_ioctl *); |
30 | |
31 | static 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 | */ |
42 | static int invalid_str(char *str, size_t size) |
43 | { |
44 | if (memchr(p: str, c: 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 | */ |
56 | static 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 | */ |
81 | static struct autofs_dev_ioctl * |
82 | copy_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 | |
102 | static 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 | */ |
111 | static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param) |
112 | { |
113 | int err; |
114 | |
115 | err = check_dev_ioctl_version(cmd, param); |
116 | if (err) { |
117 | pr_warn("invalid device control module version " |
118 | "supplied for cmd(0x%08x)\n" , cmd); |
119 | goto out; |
120 | } |
121 | |
122 | if (param->size > AUTOFS_DEV_IOCTL_SIZE) { |
123 | err = invalid_str(str: param->path, size: param->size - AUTOFS_DEV_IOCTL_SIZE); |
124 | if (err) { |
125 | pr_warn( |
126 | "path string terminator missing for cmd(0x%08x)\n" , |
127 | cmd); |
128 | goto out; |
129 | } |
130 | |
131 | err = check_name(name: param->path); |
132 | if (err) { |
133 | pr_warn("invalid path supplied for cmd(0x%08x)\n" , |
134 | cmd); |
135 | goto out; |
136 | } |
137 | } else { |
138 | unsigned int inr = _IOC_NR(cmd); |
139 | |
140 | if (inr == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD || |
141 | inr == AUTOFS_DEV_IOCTL_REQUESTER_CMD || |
142 | inr == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) { |
143 | err = -EINVAL; |
144 | goto out; |
145 | } |
146 | } |
147 | |
148 | err = 0; |
149 | out: |
150 | return err; |
151 | } |
152 | |
153 | /* Return autofs dev ioctl version */ |
154 | static int autofs_dev_ioctl_version(struct file *fp, |
155 | struct autofs_sb_info *sbi, |
156 | struct autofs_dev_ioctl *param) |
157 | { |
158 | /* This should have already been set. */ |
159 | param->ver_major = AUTOFS_DEV_IOCTL_VERSION_MAJOR; |
160 | param->ver_minor = AUTOFS_DEV_IOCTL_VERSION_MINOR; |
161 | return 0; |
162 | } |
163 | |
164 | /* Return autofs module protocol version */ |
165 | static int autofs_dev_ioctl_protover(struct file *fp, |
166 | struct autofs_sb_info *sbi, |
167 | struct autofs_dev_ioctl *param) |
168 | { |
169 | param->protover.version = sbi->version; |
170 | return 0; |
171 | } |
172 | |
173 | /* Return autofs module protocol sub version */ |
174 | static int autofs_dev_ioctl_protosubver(struct file *fp, |
175 | struct autofs_sb_info *sbi, |
176 | struct autofs_dev_ioctl *param) |
177 | { |
178 | param->protosubver.sub_version = sbi->sub_version; |
179 | return 0; |
180 | } |
181 | |
182 | /* Find the topmost mount satisfying test() */ |
183 | static int find_autofs_mount(const char *pathname, |
184 | struct path *res, |
185 | int test(const struct path *path, void *data), |
186 | void *data) |
187 | { |
188 | struct path path; |
189 | int err; |
190 | |
191 | err = kern_path(pathname, LOOKUP_MOUNTPOINT, &path); |
192 | if (err) |
193 | return err; |
194 | err = -ENOENT; |
195 | while (path.dentry == path.mnt->mnt_root) { |
196 | if (path.dentry->d_sb->s_magic == AUTOFS_SUPER_MAGIC) { |
197 | if (test(&path, data)) { |
198 | path_get(&path); |
199 | *res = path; |
200 | err = 0; |
201 | break; |
202 | } |
203 | } |
204 | if (!follow_up(&path)) |
205 | break; |
206 | } |
207 | path_put(&path); |
208 | return err; |
209 | } |
210 | |
211 | static int test_by_dev(const struct path *path, void *p) |
212 | { |
213 | return path->dentry->d_sb->s_dev == *(dev_t *)p; |
214 | } |
215 | |
216 | static int test_by_type(const struct path *path, void *p) |
217 | { |
218 | struct autofs_info *ino = autofs_dentry_ino(dentry: path->dentry); |
219 | |
220 | return ino && ino->sbi->type & *(unsigned *)p; |
221 | } |
222 | |
223 | /* |
224 | * Open a file descriptor on the autofs mount point corresponding |
225 | * to the given path and device number (aka. new_encode_dev(sb->s_dev)). |
226 | */ |
227 | static int autofs_dev_ioctl_open_mountpoint(const char *name, dev_t devid) |
228 | { |
229 | int err, fd; |
230 | |
231 | fd = get_unused_fd_flags(O_CLOEXEC); |
232 | if (likely(fd >= 0)) { |
233 | struct file *filp; |
234 | struct path path; |
235 | |
236 | err = find_autofs_mount(pathname: name, res: &path, test: test_by_dev, data: &devid); |
237 | if (err) |
238 | goto out; |
239 | |
240 | filp = dentry_open(path: &path, O_RDONLY, current_cred()); |
241 | path_put(&path); |
242 | if (IS_ERR(ptr: filp)) { |
243 | err = PTR_ERR(ptr: filp); |
244 | goto out; |
245 | } |
246 | |
247 | fd_install(fd, file: filp); |
248 | } |
249 | |
250 | return fd; |
251 | |
252 | out: |
253 | put_unused_fd(fd); |
254 | return err; |
255 | } |
256 | |
257 | /* Open a file descriptor on an autofs mount point */ |
258 | static int autofs_dev_ioctl_openmount(struct file *fp, |
259 | struct autofs_sb_info *sbi, |
260 | struct autofs_dev_ioctl *param) |
261 | { |
262 | const char *path; |
263 | dev_t devid; |
264 | int err, fd; |
265 | |
266 | /* param->path has been checked in validate_dev_ioctl() */ |
267 | |
268 | if (!param->openmount.devid) |
269 | return -EINVAL; |
270 | |
271 | param->ioctlfd = -1; |
272 | |
273 | path = param->path; |
274 | devid = new_decode_dev(dev: param->openmount.devid); |
275 | |
276 | err = 0; |
277 | fd = autofs_dev_ioctl_open_mountpoint(name: path, devid); |
278 | if (unlikely(fd < 0)) { |
279 | err = fd; |
280 | goto out; |
281 | } |
282 | |
283 | param->ioctlfd = fd; |
284 | out: |
285 | return err; |
286 | } |
287 | |
288 | /* Close file descriptor allocated above (user can also use close(2)). */ |
289 | static int autofs_dev_ioctl_closemount(struct file *fp, |
290 | struct autofs_sb_info *sbi, |
291 | struct autofs_dev_ioctl *param) |
292 | { |
293 | return close_fd(fd: param->ioctlfd); |
294 | } |
295 | |
296 | /* |
297 | * Send "ready" status for an existing wait (either a mount or an expire |
298 | * request). |
299 | */ |
300 | static int autofs_dev_ioctl_ready(struct file *fp, |
301 | struct autofs_sb_info *sbi, |
302 | struct autofs_dev_ioctl *param) |
303 | { |
304 | autofs_wqt_t token; |
305 | |
306 | token = (autofs_wqt_t) param->ready.token; |
307 | return autofs_wait_release(sbi, token, 0); |
308 | } |
309 | |
310 | /* |
311 | * Send "fail" status for an existing wait (either a mount or an expire |
312 | * request). |
313 | */ |
314 | static int autofs_dev_ioctl_fail(struct file *fp, |
315 | struct autofs_sb_info *sbi, |
316 | struct autofs_dev_ioctl *param) |
317 | { |
318 | autofs_wqt_t token; |
319 | int status; |
320 | |
321 | token = (autofs_wqt_t) param->fail.token; |
322 | status = param->fail.status < 0 ? param->fail.status : -ENOENT; |
323 | return autofs_wait_release(sbi, token, status); |
324 | } |
325 | |
326 | /* |
327 | * Set the pipe fd for kernel communication to the daemon. |
328 | * |
329 | * Normally this is set at mount using an option but if we |
330 | * are reconnecting to a busy mount then we need to use this |
331 | * to tell the autofs mount about the new kernel pipe fd. In |
332 | * order to protect mounts against incorrectly setting the |
333 | * pipefd we also require that the autofs mount be catatonic. |
334 | * |
335 | * This also sets the process group id used to identify the |
336 | * controlling process (eg. the owning automount(8) daemon). |
337 | */ |
338 | static int autofs_dev_ioctl_setpipefd(struct file *fp, |
339 | struct autofs_sb_info *sbi, |
340 | struct autofs_dev_ioctl *param) |
341 | { |
342 | int pipefd; |
343 | int err = 0; |
344 | struct pid *new_pid = NULL; |
345 | |
346 | if (param->setpipefd.pipefd == -1) |
347 | return -EINVAL; |
348 | |
349 | pipefd = param->setpipefd.pipefd; |
350 | |
351 | mutex_lock(&sbi->wq_mutex); |
352 | if (!(sbi->flags & AUTOFS_SBI_CATATONIC)) { |
353 | mutex_unlock(lock: &sbi->wq_mutex); |
354 | return -EBUSY; |
355 | } else { |
356 | struct file *pipe; |
357 | |
358 | new_pid = get_task_pid(current, type: PIDTYPE_PGID); |
359 | |
360 | if (ns_of_pid(pid: new_pid) != ns_of_pid(pid: sbi->oz_pgrp)) { |
361 | pr_warn("not allowed to change PID namespace\n" ); |
362 | err = -EINVAL; |
363 | goto out; |
364 | } |
365 | |
366 | pipe = fget(fd: pipefd); |
367 | if (!pipe) { |
368 | err = -EBADF; |
369 | goto out; |
370 | } |
371 | if (autofs_prepare_pipe(pipe) < 0) { |
372 | err = -EPIPE; |
373 | fput(pipe); |
374 | goto out; |
375 | } |
376 | swap(sbi->oz_pgrp, new_pid); |
377 | sbi->pipefd = pipefd; |
378 | sbi->pipe = pipe; |
379 | sbi->flags &= ~AUTOFS_SBI_CATATONIC; |
380 | } |
381 | out: |
382 | put_pid(pid: new_pid); |
383 | mutex_unlock(lock: &sbi->wq_mutex); |
384 | return err; |
385 | } |
386 | |
387 | /* |
388 | * Make the autofs mount point catatonic, no longer responsive to |
389 | * mount requests. Also closes the kernel pipe file descriptor. |
390 | */ |
391 | static int autofs_dev_ioctl_catatonic(struct file *fp, |
392 | struct autofs_sb_info *sbi, |
393 | struct autofs_dev_ioctl *param) |
394 | { |
395 | autofs_catatonic_mode(sbi); |
396 | return 0; |
397 | } |
398 | |
399 | /* Set the autofs mount timeout */ |
400 | static int autofs_dev_ioctl_timeout(struct file *fp, |
401 | struct autofs_sb_info *sbi, |
402 | struct autofs_dev_ioctl *param) |
403 | { |
404 | unsigned long timeout; |
405 | |
406 | timeout = param->timeout.timeout; |
407 | param->timeout.timeout = sbi->exp_timeout / HZ; |
408 | sbi->exp_timeout = timeout * HZ; |
409 | return 0; |
410 | } |
411 | |
412 | /* |
413 | * Return the uid and gid of the last request for the mount |
414 | * |
415 | * When reconstructing an autofs mount tree with active mounts |
416 | * we need to re-connect to mounts that may have used the original |
417 | * process uid and gid (or string variations of them) for mount |
418 | * lookups within the map entry. |
419 | */ |
420 | static int autofs_dev_ioctl_requester(struct file *fp, |
421 | struct autofs_sb_info *sbi, |
422 | struct autofs_dev_ioctl *param) |
423 | { |
424 | struct autofs_info *ino; |
425 | struct path path; |
426 | dev_t devid; |
427 | int err = -ENOENT; |
428 | |
429 | /* param->path has been checked in validate_dev_ioctl() */ |
430 | |
431 | devid = sbi->sb->s_dev; |
432 | |
433 | param->requester.uid = param->requester.gid = -1; |
434 | |
435 | err = find_autofs_mount(pathname: param->path, res: &path, test: test_by_dev, data: &devid); |
436 | if (err) |
437 | goto out; |
438 | |
439 | ino = autofs_dentry_ino(dentry: path.dentry); |
440 | if (ino) { |
441 | err = 0; |
442 | autofs_expire_wait(path: &path, rcu_walk: 0); |
443 | spin_lock(lock: &sbi->fs_lock); |
444 | param->requester.uid = |
445 | from_kuid_munged(current_user_ns(), uid: ino->uid); |
446 | param->requester.gid = |
447 | from_kgid_munged(current_user_ns(), gid: ino->gid); |
448 | spin_unlock(lock: &sbi->fs_lock); |
449 | } |
450 | path_put(&path); |
451 | out: |
452 | return err; |
453 | } |
454 | |
455 | /* |
456 | * Call repeatedly until it returns -EAGAIN, meaning there's nothing |
457 | * more that can be done. |
458 | */ |
459 | static int autofs_dev_ioctl_expire(struct file *fp, |
460 | struct autofs_sb_info *sbi, |
461 | struct autofs_dev_ioctl *param) |
462 | { |
463 | struct vfsmount *mnt; |
464 | int how; |
465 | |
466 | how = param->expire.how; |
467 | mnt = fp->f_path.mnt; |
468 | |
469 | return autofs_do_expire_multi(sb: sbi->sb, mnt, sbi, how); |
470 | } |
471 | |
472 | /* Check if autofs mount point is in use */ |
473 | static int autofs_dev_ioctl_askumount(struct file *fp, |
474 | struct autofs_sb_info *sbi, |
475 | struct autofs_dev_ioctl *param) |
476 | { |
477 | param->askumount.may_umount = 0; |
478 | if (may_umount(fp->f_path.mnt)) |
479 | param->askumount.may_umount = 1; |
480 | return 0; |
481 | } |
482 | |
483 | /* |
484 | * Check if the given path is a mountpoint. |
485 | * |
486 | * If we are supplied with the file descriptor of an autofs |
487 | * mount we're looking for a specific mount. In this case |
488 | * the path is considered a mountpoint if it is itself a |
489 | * mountpoint or contains a mount, such as a multi-mount |
490 | * without a root mount. In this case we return 1 if the |
491 | * path is a mount point and the super magic of the covering |
492 | * mount if there is one or 0 if it isn't a mountpoint. |
493 | * |
494 | * If we aren't supplied with a file descriptor then we |
495 | * lookup the path and check if it is the root of a mount. |
496 | * If a type is given we are looking for a particular autofs |
497 | * mount and if we don't find a match we return fail. If the |
498 | * located path is the root of a mount we return 1 along with |
499 | * the super magic of the mount or 0 otherwise. |
500 | * |
501 | * In both cases the device number (as returned by |
502 | * new_encode_dev()) is also returned. |
503 | */ |
504 | static int autofs_dev_ioctl_ismountpoint(struct file *fp, |
505 | struct autofs_sb_info *sbi, |
506 | struct autofs_dev_ioctl *param) |
507 | { |
508 | struct path path; |
509 | const char *name; |
510 | unsigned int type; |
511 | unsigned int devid, magic; |
512 | int err = -ENOENT; |
513 | |
514 | /* param->path has been checked in validate_dev_ioctl() */ |
515 | |
516 | name = param->path; |
517 | type = param->ismountpoint.in.type; |
518 | |
519 | param->ismountpoint.out.devid = devid = 0; |
520 | param->ismountpoint.out.magic = magic = 0; |
521 | |
522 | if (!fp || param->ioctlfd == -1) { |
523 | if (autofs_type_any(type)) |
524 | err = kern_path(name, LOOKUP_FOLLOW | LOOKUP_MOUNTPOINT, |
525 | &path); |
526 | else |
527 | err = find_autofs_mount(pathname: name, res: &path, |
528 | test: test_by_type, data: &type); |
529 | if (err) |
530 | goto out; |
531 | devid = new_encode_dev(dev: path.dentry->d_sb->s_dev); |
532 | err = 0; |
533 | if (path.mnt->mnt_root == path.dentry) { |
534 | err = 1; |
535 | magic = path.dentry->d_sb->s_magic; |
536 | } |
537 | } else { |
538 | dev_t dev = sbi->sb->s_dev; |
539 | |
540 | err = find_autofs_mount(pathname: name, res: &path, test: test_by_dev, data: &dev); |
541 | if (err) |
542 | goto out; |
543 | |
544 | devid = new_encode_dev(dev); |
545 | |
546 | err = path_has_submounts(&path); |
547 | |
548 | if (follow_down_one(&path)) |
549 | magic = path.dentry->d_sb->s_magic; |
550 | } |
551 | |
552 | param->ismountpoint.out.devid = devid; |
553 | param->ismountpoint.out.magic = magic; |
554 | path_put(&path); |
555 | out: |
556 | return err; |
557 | } |
558 | |
559 | /* |
560 | * Our range of ioctl numbers isn't 0 based so we need to shift |
561 | * the array index by _IOC_NR(AUTOFS_CTL_IOC_FIRST) for the table |
562 | * lookup. |
563 | */ |
564 | #define cmd_idx(cmd) (cmd - _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST)) |
565 | |
566 | static ioctl_fn lookup_dev_ioctl(unsigned int cmd) |
567 | { |
568 | static const ioctl_fn _ioctls[] = { |
569 | autofs_dev_ioctl_version, |
570 | autofs_dev_ioctl_protover, |
571 | autofs_dev_ioctl_protosubver, |
572 | autofs_dev_ioctl_openmount, |
573 | autofs_dev_ioctl_closemount, |
574 | autofs_dev_ioctl_ready, |
575 | autofs_dev_ioctl_fail, |
576 | autofs_dev_ioctl_setpipefd, |
577 | autofs_dev_ioctl_catatonic, |
578 | autofs_dev_ioctl_timeout, |
579 | autofs_dev_ioctl_requester, |
580 | autofs_dev_ioctl_expire, |
581 | autofs_dev_ioctl_askumount, |
582 | autofs_dev_ioctl_ismountpoint, |
583 | }; |
584 | unsigned int idx = cmd_idx(cmd); |
585 | |
586 | if (idx >= ARRAY_SIZE(_ioctls)) |
587 | return NULL; |
588 | idx = array_index_nospec(idx, ARRAY_SIZE(_ioctls)); |
589 | return _ioctls[idx]; |
590 | } |
591 | |
592 | /* ioctl dispatcher */ |
593 | static int _autofs_dev_ioctl(unsigned int command, |
594 | struct autofs_dev_ioctl __user *user) |
595 | { |
596 | struct autofs_dev_ioctl *param; |
597 | struct file *fp; |
598 | struct autofs_sb_info *sbi; |
599 | unsigned int cmd_first, cmd; |
600 | ioctl_fn fn = NULL; |
601 | int err = 0; |
602 | |
603 | cmd_first = _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST); |
604 | cmd = _IOC_NR(command); |
605 | |
606 | if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) || |
607 | cmd - cmd_first > AUTOFS_DEV_IOCTL_IOC_COUNT) { |
608 | return -ENOTTY; |
609 | } |
610 | |
611 | /* Only root can use ioctls other than AUTOFS_DEV_IOCTL_VERSION_CMD |
612 | * and AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD |
613 | */ |
614 | if (cmd != AUTOFS_DEV_IOCTL_VERSION_CMD && |
615 | cmd != AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD && |
616 | !capable(CAP_SYS_ADMIN)) |
617 | return -EPERM; |
618 | |
619 | /* Copy the parameters into kernel space. */ |
620 | param = copy_dev_ioctl(in: user); |
621 | if (IS_ERR(ptr: param)) |
622 | return PTR_ERR(ptr: param); |
623 | |
624 | err = validate_dev_ioctl(cmd: command, param); |
625 | if (err) |
626 | goto out; |
627 | |
628 | fn = lookup_dev_ioctl(cmd); |
629 | if (!fn) { |
630 | pr_warn("unknown command 0x%08x\n" , command); |
631 | err = -ENOTTY; |
632 | goto out; |
633 | } |
634 | |
635 | fp = NULL; |
636 | sbi = NULL; |
637 | |
638 | /* |
639 | * For obvious reasons the openmount can't have a file |
640 | * descriptor yet. We don't take a reference to the |
641 | * file during close to allow for immediate release, |
642 | * and the same for retrieving ioctl version. |
643 | */ |
644 | if (cmd != AUTOFS_DEV_IOCTL_VERSION_CMD && |
645 | cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD && |
646 | cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) { |
647 | struct super_block *sb; |
648 | |
649 | fp = fget(fd: param->ioctlfd); |
650 | if (!fp) { |
651 | if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) |
652 | goto cont; |
653 | err = -EBADF; |
654 | goto out; |
655 | } |
656 | |
657 | sb = file_inode(f: fp)->i_sb; |
658 | if (sb->s_type != &autofs_fs_type) { |
659 | err = -EINVAL; |
660 | fput(fp); |
661 | goto out; |
662 | } |
663 | sbi = autofs_sbi(sb); |
664 | |
665 | /* |
666 | * Admin needs to be able to set the mount catatonic in |
667 | * order to be able to perform the re-open. |
668 | */ |
669 | if (!autofs_oz_mode(sbi) && |
670 | cmd != AUTOFS_DEV_IOCTL_CATATONIC_CMD) { |
671 | err = -EACCES; |
672 | fput(fp); |
673 | goto out; |
674 | } |
675 | } |
676 | cont: |
677 | err = fn(fp, sbi, param); |
678 | |
679 | if (fp) |
680 | fput(fp); |
681 | if (err >= 0 && copy_to_user(to: user, from: param, AUTOFS_DEV_IOCTL_SIZE)) |
682 | err = -EFAULT; |
683 | out: |
684 | free_dev_ioctl(param); |
685 | return err; |
686 | } |
687 | |
688 | static long autofs_dev_ioctl(struct file *file, unsigned int command, |
689 | unsigned long u) |
690 | { |
691 | int err; |
692 | |
693 | err = _autofs_dev_ioctl(command, user: (struct autofs_dev_ioctl __user *) u); |
694 | return (long) err; |
695 | } |
696 | |
697 | #ifdef CONFIG_COMPAT |
698 | static long autofs_dev_ioctl_compat(struct file *file, unsigned int command, |
699 | unsigned long u) |
700 | { |
701 | return autofs_dev_ioctl(file, command, u: (unsigned long) compat_ptr(uptr: u)); |
702 | } |
703 | #else |
704 | #define autofs_dev_ioctl_compat NULL |
705 | #endif |
706 | |
707 | static const struct file_operations _dev_ioctl_fops = { |
708 | .unlocked_ioctl = autofs_dev_ioctl, |
709 | .compat_ioctl = autofs_dev_ioctl_compat, |
710 | .owner = THIS_MODULE, |
711 | .llseek = noop_llseek, |
712 | }; |
713 | |
714 | static struct miscdevice _autofs_dev_ioctl_misc = { |
715 | .minor = AUTOFS_MINOR, |
716 | .name = AUTOFS_DEVICE_NAME, |
717 | .fops = &_dev_ioctl_fops, |
718 | .mode = 0644, |
719 | }; |
720 | |
721 | MODULE_ALIAS_MISCDEV(AUTOFS_MINOR); |
722 | MODULE_ALIAS("devname:autofs" ); |
723 | |
724 | /* Register/deregister misc character device */ |
725 | int __init autofs_dev_ioctl_init(void) |
726 | { |
727 | int r; |
728 | |
729 | r = misc_register(misc: &_autofs_dev_ioctl_misc); |
730 | if (r) { |
731 | pr_err("misc_register failed for control device\n" ); |
732 | return r; |
733 | } |
734 | |
735 | return 0; |
736 | } |
737 | |
738 | void autofs_dev_ioctl_exit(void) |
739 | { |
740 | misc_deregister(misc: &_autofs_dev_ioctl_misc); |
741 | } |
742 | |