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d6910058 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
ebc921ca IK |
2 | /* |
3 | * Copyright 2008 Red Hat, Inc. All rights reserved. | |
4 | * Copyright 2008 Ian Kent <raven@themaw.net> | |
ebc921ca IK |
5 | */ |
6 | ||
ebc921ca | 7 | #include <linux/miscdevice.h> |
ebc921ca IK |
8 | #include <linux/compat.h> |
9 | #include <linux/syscalls.h> | |
10 | #include <linux/magic.h> | |
ebc921ca IK |
11 | |
12 | #include "autofs_i.h" | |
13 | ||
14 | /* | |
15 | * This module implements an interface for routing autofs ioctl control | |
16 | * commands via a miscellaneous device file. | |
17 | * | |
18 | * The alternate interface is needed because we need to be able open | |
19 | * an ioctl file descriptor on an autofs mount that may be covered by | |
20 | * another mount. This situation arises when starting automount(8) | |
21 | * or other user space daemon which uses direct mounts or offset | |
22 | * mounts (used for autofs lazy mount/umount of nested mount trees), | |
23 | * which have been left busy at at service shutdown. | |
24 | */ | |
25 | ||
26 | typedef int (*ioctl_fn)(struct file *, struct autofs_sb_info *, | |
27 | struct autofs_dev_ioctl *); | |
28 | ||
29 | static int check_name(const char *name) | |
30 | { | |
31 | if (!strchr(name, '/')) | |
32 | return -EINVAL; | |
33 | return 0; | |
34 | } | |
35 | ||
36 | /* | |
37 | * Check a string doesn't overrun the chunk of | |
38 | * memory we copied from user land. | |
39 | */ | |
40 | static int invalid_str(char *str, size_t size) | |
41 | { | |
42 | if (memchr(str, 0, size)) | |
43 | return 0; | |
44 | return -EINVAL; | |
45 | } | |
46 | ||
47 | /* | |
48 | * Check that the user compiled against correct version of autofs | |
49 | * misc device code. | |
50 | * | |
51 | * As well as checking the version compatibility this always copies | |
52 | * the kernel interface version out. | |
53 | */ | |
54 | static int check_dev_ioctl_version(int cmd, struct autofs_dev_ioctl *param) | |
55 | { | |
56 | int err = 0; | |
57 | ||
58 | if ((param->ver_major != AUTOFS_DEV_IOCTL_VERSION_MAJOR) || | |
59 | (param->ver_minor > AUTOFS_DEV_IOCTL_VERSION_MINOR)) { | |
60 | pr_warn("ioctl control interface version mismatch: " | |
61 | "kernel(%u.%u), user(%u.%u), cmd(0x%08x)\n", | |
62 | AUTOFS_DEV_IOCTL_VERSION_MAJOR, | |
63 | AUTOFS_DEV_IOCTL_VERSION_MINOR, | |
64 | param->ver_major, param->ver_minor, cmd); | |
65 | err = -EINVAL; | |
66 | } | |
67 | ||
68 | /* Fill in the kernel version. */ | |
69 | param->ver_major = AUTOFS_DEV_IOCTL_VERSION_MAJOR; | |
70 | param->ver_minor = AUTOFS_DEV_IOCTL_VERSION_MINOR; | |
71 | ||
72 | return err; | |
73 | } | |
74 | ||
75 | /* | |
76 | * Copy parameter control struct, including a possible path allocated | |
77 | * at the end of the struct. | |
78 | */ | |
79 | static struct autofs_dev_ioctl * | |
80 | copy_dev_ioctl(struct autofs_dev_ioctl __user *in) | |
81 | { | |
82 | struct autofs_dev_ioctl tmp, *res; | |
83 | ||
84 | if (copy_from_user(&tmp, in, AUTOFS_DEV_IOCTL_SIZE)) | |
85 | return ERR_PTR(-EFAULT); | |
86 | ||
87 | if (tmp.size < AUTOFS_DEV_IOCTL_SIZE) | |
88 | return ERR_PTR(-EINVAL); | |
89 | ||
90 | if (tmp.size > AUTOFS_DEV_IOCTL_SIZE + PATH_MAX) | |
91 | return ERR_PTR(-ENAMETOOLONG); | |
92 | ||
93 | res = memdup_user(in, tmp.size); | |
94 | if (!IS_ERR(res)) | |
95 | res->size = tmp.size; | |
96 | ||
97 | return res; | |
98 | } | |
99 | ||
100 | static inline void free_dev_ioctl(struct autofs_dev_ioctl *param) | |
101 | { | |
102 | kfree(param); | |
103 | } | |
104 | ||
105 | /* | |
106 | * Check sanity of parameter control fields and if a path is present | |
107 | * check that it is terminated and contains at least one "/". | |
108 | */ | |
109 | static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param) | |
110 | { | |
111 | int err; | |
112 | ||
113 | err = check_dev_ioctl_version(cmd, param); | |
114 | if (err) { | |
115 | pr_warn("invalid device control module version " | |
116 | "supplied for cmd(0x%08x)\n", cmd); | |
117 | goto out; | |
118 | } | |
119 | ||
120 | if (param->size > AUTOFS_DEV_IOCTL_SIZE) { | |
121 | err = invalid_str(param->path, param->size - AUTOFS_DEV_IOCTL_SIZE); | |
122 | if (err) { | |
123 | pr_warn( | |
124 | "path string terminator missing for cmd(0x%08x)\n", | |
125 | cmd); | |
126 | goto out; | |
127 | } | |
128 | ||
129 | err = check_name(param->path); | |
130 | if (err) { | |
131 | pr_warn("invalid path supplied for cmd(0x%08x)\n", | |
132 | cmd); | |
133 | goto out; | |
134 | } | |
02f51d45 TB |
135 | } else { |
136 | unsigned int inr = _IOC_NR(cmd); | |
137 | ||
138 | if (inr == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD || | |
139 | inr == AUTOFS_DEV_IOCTL_REQUESTER_CMD || | |
140 | inr == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) { | |
141 | err = -EINVAL; | |
142 | goto out; | |
143 | } | |
ebc921ca IK |
144 | } |
145 | ||
146 | err = 0; | |
147 | out: | |
148 | return err; | |
149 | } | |
150 | ||
ebc921ca IK |
151 | /* Return autofs dev ioctl version */ |
152 | static int autofs_dev_ioctl_version(struct file *fp, | |
153 | struct autofs_sb_info *sbi, | |
154 | struct autofs_dev_ioctl *param) | |
155 | { | |
156 | /* This should have already been set. */ | |
157 | param->ver_major = AUTOFS_DEV_IOCTL_VERSION_MAJOR; | |
158 | param->ver_minor = AUTOFS_DEV_IOCTL_VERSION_MINOR; | |
159 | return 0; | |
160 | } | |
161 | ||
162 | /* Return autofs module protocol version */ | |
163 | static int autofs_dev_ioctl_protover(struct file *fp, | |
164 | struct autofs_sb_info *sbi, | |
165 | struct autofs_dev_ioctl *param) | |
166 | { | |
167 | param->protover.version = sbi->version; | |
168 | return 0; | |
169 | } | |
170 | ||
171 | /* Return autofs module protocol sub version */ | |
172 | static int autofs_dev_ioctl_protosubver(struct file *fp, | |
173 | struct autofs_sb_info *sbi, | |
174 | struct autofs_dev_ioctl *param) | |
175 | { | |
176 | param->protosubver.sub_version = sbi->sub_version; | |
177 | return 0; | |
178 | } | |
179 | ||
180 | /* Find the topmost mount satisfying test() */ | |
181 | static int find_autofs_mount(const char *pathname, | |
182 | struct path *res, | |
183 | int test(const struct path *path, void *data), | |
184 | void *data) | |
185 | { | |
186 | struct path path; | |
187 | int err; | |
188 | ||
189 | err = kern_path_mountpoint(AT_FDCWD, pathname, &path, 0); | |
190 | if (err) | |
191 | return err; | |
192 | err = -ENOENT; | |
193 | while (path.dentry == path.mnt->mnt_root) { | |
194 | if (path.dentry->d_sb->s_magic == AUTOFS_SUPER_MAGIC) { | |
195 | if (test(&path, data)) { | |
196 | path_get(&path); | |
197 | *res = path; | |
198 | err = 0; | |
199 | break; | |
200 | } | |
201 | } | |
202 | if (!follow_up(&path)) | |
203 | break; | |
204 | } | |
205 | path_put(&path); | |
206 | return err; | |
207 | } | |
208 | ||
209 | static int test_by_dev(const struct path *path, void *p) | |
210 | { | |
211 | return path->dentry->d_sb->s_dev == *(dev_t *)p; | |
212 | } | |
213 | ||
214 | static int test_by_type(const struct path *path, void *p) | |
215 | { | |
216 | struct autofs_info *ino = autofs_dentry_ino(path->dentry); | |
217 | ||
218 | return ino && ino->sbi->type & *(unsigned *)p; | |
219 | } | |
220 | ||
221 | /* | |
222 | * Open a file descriptor on the autofs mount point corresponding | |
223 | * to the given path and device number (aka. new_encode_dev(sb->s_dev)). | |
224 | */ | |
225 | static int autofs_dev_ioctl_open_mountpoint(const char *name, dev_t devid) | |
226 | { | |
227 | int err, fd; | |
228 | ||
229 | fd = get_unused_fd_flags(O_CLOEXEC); | |
230 | if (likely(fd >= 0)) { | |
231 | struct file *filp; | |
232 | struct path path; | |
233 | ||
234 | err = find_autofs_mount(name, &path, test_by_dev, &devid); | |
235 | if (err) | |
236 | goto out; | |
237 | ||
238 | filp = dentry_open(&path, O_RDONLY, current_cred()); | |
239 | path_put(&path); | |
240 | if (IS_ERR(filp)) { | |
241 | err = PTR_ERR(filp); | |
242 | goto out; | |
243 | } | |
244 | ||
245 | fd_install(fd, filp); | |
246 | } | |
247 | ||
248 | return fd; | |
249 | ||
250 | out: | |
251 | put_unused_fd(fd); | |
252 | return err; | |
253 | } | |
254 | ||
255 | /* Open a file descriptor on an autofs mount point */ | |
256 | static int autofs_dev_ioctl_openmount(struct file *fp, | |
257 | struct autofs_sb_info *sbi, | |
258 | struct autofs_dev_ioctl *param) | |
259 | { | |
260 | const char *path; | |
261 | dev_t devid; | |
262 | int err, fd; | |
263 | ||
02f51d45 TB |
264 | /* param->path has been checked in validate_dev_ioctl() */ |
265 | ||
ebc921ca IK |
266 | if (!param->openmount.devid) |
267 | return -EINVAL; | |
268 | ||
269 | param->ioctlfd = -1; | |
270 | ||
271 | path = param->path; | |
272 | devid = new_decode_dev(param->openmount.devid); | |
273 | ||
274 | err = 0; | |
275 | fd = autofs_dev_ioctl_open_mountpoint(path, devid); | |
276 | if (unlikely(fd < 0)) { | |
277 | err = fd; | |
278 | goto out; | |
279 | } | |
280 | ||
281 | param->ioctlfd = fd; | |
282 | out: | |
283 | return err; | |
284 | } | |
285 | ||
286 | /* Close file descriptor allocated above (user can also use close(2)). */ | |
287 | static int autofs_dev_ioctl_closemount(struct file *fp, | |
288 | struct autofs_sb_info *sbi, | |
289 | struct autofs_dev_ioctl *param) | |
290 | { | |
291 | return ksys_close(param->ioctlfd); | |
292 | } | |
293 | ||
294 | /* | |
295 | * Send "ready" status for an existing wait (either a mount or an expire | |
296 | * request). | |
297 | */ | |
298 | static int autofs_dev_ioctl_ready(struct file *fp, | |
299 | struct autofs_sb_info *sbi, | |
300 | struct autofs_dev_ioctl *param) | |
301 | { | |
302 | autofs_wqt_t token; | |
303 | ||
304 | token = (autofs_wqt_t) param->ready.token; | |
305 | return autofs_wait_release(sbi, token, 0); | |
306 | } | |
307 | ||
308 | /* | |
309 | * Send "fail" status for an existing wait (either a mount or an expire | |
310 | * request). | |
311 | */ | |
312 | static int autofs_dev_ioctl_fail(struct file *fp, | |
313 | struct autofs_sb_info *sbi, | |
314 | struct autofs_dev_ioctl *param) | |
315 | { | |
316 | autofs_wqt_t token; | |
317 | int status; | |
318 | ||
319 | token = (autofs_wqt_t) param->fail.token; | |
320 | status = param->fail.status < 0 ? param->fail.status : -ENOENT; | |
321 | return autofs_wait_release(sbi, token, status); | |
322 | } | |
323 | ||
324 | /* | |
325 | * Set the pipe fd for kernel communication to the daemon. | |
326 | * | |
327 | * Normally this is set at mount using an option but if we | |
328 | * are reconnecting to a busy mount then we need to use this | |
329 | * to tell the autofs mount about the new kernel pipe fd. In | |
330 | * order to protect mounts against incorrectly setting the | |
331 | * pipefd we also require that the autofs mount be catatonic. | |
332 | * | |
333 | * This also sets the process group id used to identify the | |
334 | * controlling process (eg. the owning automount(8) daemon). | |
335 | */ | |
336 | static int autofs_dev_ioctl_setpipefd(struct file *fp, | |
337 | struct autofs_sb_info *sbi, | |
338 | struct autofs_dev_ioctl *param) | |
339 | { | |
340 | int pipefd; | |
341 | int err = 0; | |
342 | struct pid *new_pid = NULL; | |
343 | ||
344 | if (param->setpipefd.pipefd == -1) | |
345 | return -EINVAL; | |
346 | ||
347 | pipefd = param->setpipefd.pipefd; | |
348 | ||
349 | mutex_lock(&sbi->wq_mutex); | |
9d8719a4 | 350 | if (!(sbi->flags & AUTOFS_SBI_CATATONIC)) { |
ebc921ca IK |
351 | mutex_unlock(&sbi->wq_mutex); |
352 | return -EBUSY; | |
353 | } else { | |
354 | struct file *pipe; | |
355 | ||
356 | new_pid = get_task_pid(current, PIDTYPE_PGID); | |
357 | ||
358 | if (ns_of_pid(new_pid) != ns_of_pid(sbi->oz_pgrp)) { | |
359 | pr_warn("not allowed to change PID namespace\n"); | |
360 | err = -EINVAL; | |
361 | goto out; | |
362 | } | |
363 | ||
364 | pipe = fget(pipefd); | |
365 | if (!pipe) { | |
366 | err = -EBADF; | |
367 | goto out; | |
368 | } | |
369 | if (autofs_prepare_pipe(pipe) < 0) { | |
370 | err = -EPIPE; | |
371 | fput(pipe); | |
372 | goto out; | |
373 | } | |
374 | swap(sbi->oz_pgrp, new_pid); | |
375 | sbi->pipefd = pipefd; | |
376 | sbi->pipe = pipe; | |
9d8719a4 | 377 | sbi->flags &= ~AUTOFS_SBI_CATATONIC; |
ebc921ca IK |
378 | } |
379 | out: | |
380 | put_pid(new_pid); | |
381 | mutex_unlock(&sbi->wq_mutex); | |
382 | return err; | |
383 | } | |
384 | ||
385 | /* | |
386 | * Make the autofs mount point catatonic, no longer responsive to | |
387 | * mount requests. Also closes the kernel pipe file descriptor. | |
388 | */ | |
389 | static int autofs_dev_ioctl_catatonic(struct file *fp, | |
390 | struct autofs_sb_info *sbi, | |
391 | struct autofs_dev_ioctl *param) | |
392 | { | |
393 | autofs_catatonic_mode(sbi); | |
394 | return 0; | |
395 | } | |
396 | ||
397 | /* Set the autofs mount timeout */ | |
398 | static int autofs_dev_ioctl_timeout(struct file *fp, | |
399 | struct autofs_sb_info *sbi, | |
400 | struct autofs_dev_ioctl *param) | |
401 | { | |
402 | unsigned long timeout; | |
403 | ||
404 | timeout = param->timeout.timeout; | |
405 | param->timeout.timeout = sbi->exp_timeout / HZ; | |
406 | sbi->exp_timeout = timeout * HZ; | |
407 | return 0; | |
408 | } | |
409 | ||
410 | /* | |
411 | * Return the uid and gid of the last request for the mount | |
412 | * | |
413 | * When reconstructing an autofs mount tree with active mounts | |
414 | * we need to re-connect to mounts that may have used the original | |
415 | * process uid and gid (or string variations of them) for mount | |
416 | * lookups within the map entry. | |
417 | */ | |
418 | static int autofs_dev_ioctl_requester(struct file *fp, | |
419 | struct autofs_sb_info *sbi, | |
420 | struct autofs_dev_ioctl *param) | |
421 | { | |
422 | struct autofs_info *ino; | |
423 | struct path path; | |
424 | dev_t devid; | |
425 | int err = -ENOENT; | |
426 | ||
02f51d45 | 427 | /* param->path has been checked in validate_dev_ioctl() */ |
ebc921ca IK |
428 | |
429 | devid = sbi->sb->s_dev; | |
430 | ||
431 | param->requester.uid = param->requester.gid = -1; | |
432 | ||
433 | err = find_autofs_mount(param->path, &path, test_by_dev, &devid); | |
434 | if (err) | |
435 | goto out; | |
436 | ||
437 | ino = autofs_dentry_ino(path.dentry); | |
438 | if (ino) { | |
439 | err = 0; | |
440 | autofs_expire_wait(&path, 0); | |
441 | spin_lock(&sbi->fs_lock); | |
442 | param->requester.uid = | |
443 | from_kuid_munged(current_user_ns(), ino->uid); | |
444 | param->requester.gid = | |
445 | from_kgid_munged(current_user_ns(), ino->gid); | |
446 | spin_unlock(&sbi->fs_lock); | |
447 | } | |
448 | path_put(&path); | |
449 | out: | |
450 | return err; | |
451 | } | |
452 | ||
453 | /* | |
454 | * Call repeatedly until it returns -EAGAIN, meaning there's nothing | |
455 | * more that can be done. | |
456 | */ | |
457 | static int autofs_dev_ioctl_expire(struct file *fp, | |
458 | struct autofs_sb_info *sbi, | |
459 | struct autofs_dev_ioctl *param) | |
460 | { | |
461 | struct vfsmount *mnt; | |
462 | int how; | |
463 | ||
464 | how = param->expire.how; | |
465 | mnt = fp->f_path.mnt; | |
466 | ||
467 | return autofs_do_expire_multi(sbi->sb, mnt, sbi, how); | |
468 | } | |
469 | ||
470 | /* Check if autofs mount point is in use */ | |
471 | static int autofs_dev_ioctl_askumount(struct file *fp, | |
472 | struct autofs_sb_info *sbi, | |
473 | struct autofs_dev_ioctl *param) | |
474 | { | |
475 | param->askumount.may_umount = 0; | |
476 | if (may_umount(fp->f_path.mnt)) | |
477 | param->askumount.may_umount = 1; | |
478 | return 0; | |
479 | } | |
480 | ||
481 | /* | |
482 | * Check if the given path is a mountpoint. | |
483 | * | |
484 | * If we are supplied with the file descriptor of an autofs | |
485 | * mount we're looking for a specific mount. In this case | |
486 | * the path is considered a mountpoint if it is itself a | |
487 | * mountpoint or contains a mount, such as a multi-mount | |
488 | * without a root mount. In this case we return 1 if the | |
489 | * path is a mount point and the super magic of the covering | |
490 | * mount if there is one or 0 if it isn't a mountpoint. | |
491 | * | |
492 | * If we aren't supplied with a file descriptor then we | |
493 | * lookup the path and check if it is the root of a mount. | |
494 | * If a type is given we are looking for a particular autofs | |
495 | * mount and if we don't find a match we return fail. If the | |
496 | * located path is the root of a mount we return 1 along with | |
497 | * the super magic of the mount or 0 otherwise. | |
498 | * | |
499 | * In both cases the the device number (as returned by | |
500 | * new_encode_dev()) is also returned. | |
501 | */ | |
502 | static int autofs_dev_ioctl_ismountpoint(struct file *fp, | |
503 | struct autofs_sb_info *sbi, | |
504 | struct autofs_dev_ioctl *param) | |
505 | { | |
506 | struct path path; | |
507 | const char *name; | |
508 | unsigned int type; | |
509 | unsigned int devid, magic; | |
510 | int err = -ENOENT; | |
511 | ||
02f51d45 | 512 | /* param->path has been checked in validate_dev_ioctl() */ |
ebc921ca IK |
513 | |
514 | name = param->path; | |
515 | type = param->ismountpoint.in.type; | |
516 | ||
517 | param->ismountpoint.out.devid = devid = 0; | |
518 | param->ismountpoint.out.magic = magic = 0; | |
519 | ||
520 | if (!fp || param->ioctlfd == -1) { | |
521 | if (autofs_type_any(type)) | |
522 | err = kern_path_mountpoint(AT_FDCWD, | |
523 | name, &path, LOOKUP_FOLLOW); | |
524 | else | |
525 | err = find_autofs_mount(name, &path, | |
526 | test_by_type, &type); | |
527 | if (err) | |
528 | goto out; | |
529 | devid = new_encode_dev(path.dentry->d_sb->s_dev); | |
530 | err = 0; | |
531 | if (path.mnt->mnt_root == path.dentry) { | |
532 | err = 1; | |
533 | magic = path.dentry->d_sb->s_magic; | |
534 | } | |
535 | } else { | |
536 | dev_t dev = sbi->sb->s_dev; | |
537 | ||
538 | err = find_autofs_mount(name, &path, test_by_dev, &dev); | |
539 | if (err) | |
540 | goto out; | |
541 | ||
542 | devid = new_encode_dev(dev); | |
543 | ||
544 | err = path_has_submounts(&path); | |
545 | ||
546 | if (follow_down_one(&path)) | |
547 | magic = path.dentry->d_sb->s_magic; | |
548 | } | |
549 | ||
550 | param->ismountpoint.out.devid = devid; | |
551 | param->ismountpoint.out.magic = magic; | |
552 | path_put(&path); | |
553 | out: | |
554 | return err; | |
555 | } | |
556 | ||
557 | /* | |
558 | * Our range of ioctl numbers isn't 0 based so we need to shift | |
559 | * the array index by _IOC_NR(AUTOFS_CTL_IOC_FIRST) for the table | |
560 | * lookup. | |
561 | */ | |
562 | #define cmd_idx(cmd) (cmd - _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST)) | |
563 | ||
564 | static ioctl_fn lookup_dev_ioctl(unsigned int cmd) | |
565 | { | |
566 | static ioctl_fn _ioctls[] = { | |
567 | autofs_dev_ioctl_version, | |
568 | autofs_dev_ioctl_protover, | |
569 | autofs_dev_ioctl_protosubver, | |
570 | autofs_dev_ioctl_openmount, | |
571 | autofs_dev_ioctl_closemount, | |
572 | autofs_dev_ioctl_ready, | |
573 | autofs_dev_ioctl_fail, | |
574 | autofs_dev_ioctl_setpipefd, | |
575 | autofs_dev_ioctl_catatonic, | |
576 | autofs_dev_ioctl_timeout, | |
577 | autofs_dev_ioctl_requester, | |
578 | autofs_dev_ioctl_expire, | |
579 | autofs_dev_ioctl_askumount, | |
580 | autofs_dev_ioctl_ismountpoint, | |
581 | }; | |
582 | unsigned int idx = cmd_idx(cmd); | |
583 | ||
584 | return (idx >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[idx]; | |
585 | } | |
586 | ||
587 | /* ioctl dispatcher */ | |
588 | static int _autofs_dev_ioctl(unsigned int command, | |
589 | struct autofs_dev_ioctl __user *user) | |
590 | { | |
591 | struct autofs_dev_ioctl *param; | |
592 | struct file *fp; | |
593 | struct autofs_sb_info *sbi; | |
594 | unsigned int cmd_first, cmd; | |
595 | ioctl_fn fn = NULL; | |
596 | int err = 0; | |
597 | ||
598 | cmd_first = _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST); | |
599 | cmd = _IOC_NR(command); | |
600 | ||
601 | if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) || | |
602 | cmd - cmd_first > AUTOFS_DEV_IOCTL_IOC_COUNT) { | |
603 | return -ENOTTY; | |
604 | } | |
605 | ||
606 | /* Only root can use ioctls other than AUTOFS_DEV_IOCTL_VERSION_CMD | |
607 | * and AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD | |
608 | */ | |
609 | if (cmd != AUTOFS_DEV_IOCTL_VERSION_CMD && | |
610 | cmd != AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD && | |
611 | !capable(CAP_SYS_ADMIN)) | |
612 | return -EPERM; | |
613 | ||
614 | /* Copy the parameters into kernel space. */ | |
615 | param = copy_dev_ioctl(user); | |
616 | if (IS_ERR(param)) | |
617 | return PTR_ERR(param); | |
618 | ||
619 | err = validate_dev_ioctl(command, param); | |
620 | if (err) | |
621 | goto out; | |
622 | ||
623 | fn = lookup_dev_ioctl(cmd); | |
624 | if (!fn) { | |
625 | pr_warn("unknown command 0x%08x\n", command); | |
626 | err = -ENOTTY; | |
627 | goto out; | |
628 | } | |
629 | ||
630 | fp = NULL; | |
631 | sbi = NULL; | |
632 | ||
633 | /* | |
634 | * For obvious reasons the openmount can't have a file | |
635 | * descriptor yet. We don't take a reference to the | |
636 | * file during close to allow for immediate release, | |
637 | * and the same for retrieving ioctl version. | |
638 | */ | |
639 | if (cmd != AUTOFS_DEV_IOCTL_VERSION_CMD && | |
640 | cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD && | |
641 | cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) { | |
55f0d820 IK |
642 | struct super_block *sb; |
643 | ||
ebc921ca IK |
644 | fp = fget(param->ioctlfd); |
645 | if (!fp) { | |
646 | if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) | |
647 | goto cont; | |
648 | err = -EBADF; | |
649 | goto out; | |
650 | } | |
651 | ||
55f0d820 IK |
652 | sb = file_inode(fp)->i_sb; |
653 | if (sb->s_type != &autofs_fs_type) { | |
ebc921ca IK |
654 | err = -EINVAL; |
655 | fput(fp); | |
656 | goto out; | |
657 | } | |
55f0d820 | 658 | sbi = autofs_sbi(sb); |
ebc921ca IK |
659 | |
660 | /* | |
661 | * Admin needs to be able to set the mount catatonic in | |
662 | * order to be able to perform the re-open. | |
663 | */ | |
664 | if (!autofs_oz_mode(sbi) && | |
665 | cmd != AUTOFS_DEV_IOCTL_CATATONIC_CMD) { | |
666 | err = -EACCES; | |
667 | fput(fp); | |
668 | goto out; | |
669 | } | |
670 | } | |
671 | cont: | |
672 | err = fn(fp, sbi, param); | |
673 | ||
674 | if (fp) | |
675 | fput(fp); | |
676 | if (err >= 0 && copy_to_user(user, param, AUTOFS_DEV_IOCTL_SIZE)) | |
677 | err = -EFAULT; | |
678 | out: | |
679 | free_dev_ioctl(param); | |
680 | return err; | |
681 | } | |
682 | ||
683 | static long autofs_dev_ioctl(struct file *file, unsigned int command, | |
684 | unsigned long u) | |
685 | { | |
686 | int err; | |
687 | ||
688 | err = _autofs_dev_ioctl(command, (struct autofs_dev_ioctl __user *) u); | |
689 | return (long) err; | |
690 | } | |
691 | ||
692 | #ifdef CONFIG_COMPAT | |
693 | static long autofs_dev_ioctl_compat(struct file *file, unsigned int command, | |
694 | unsigned long u) | |
695 | { | |
696 | return autofs_dev_ioctl(file, command, (unsigned long) compat_ptr(u)); | |
697 | } | |
698 | #else | |
699 | #define autofs_dev_ioctl_compat NULL | |
700 | #endif | |
701 | ||
702 | static const struct file_operations _dev_ioctl_fops = { | |
703 | .unlocked_ioctl = autofs_dev_ioctl, | |
704 | .compat_ioctl = autofs_dev_ioctl_compat, | |
705 | .owner = THIS_MODULE, | |
706 | .llseek = noop_llseek, | |
707 | }; | |
708 | ||
709 | static struct miscdevice _autofs_dev_ioctl_misc = { | |
710 | .minor = AUTOFS_MINOR, | |
711 | .name = AUTOFS_DEVICE_NAME, | |
712 | .fops = &_dev_ioctl_fops, | |
713 | .mode = 0644, | |
714 | }; | |
715 | ||
716 | MODULE_ALIAS_MISCDEV(AUTOFS_MINOR); | |
717 | MODULE_ALIAS("devname:autofs"); | |
718 | ||
719 | /* Register/deregister misc character device */ | |
720 | int __init autofs_dev_ioctl_init(void) | |
721 | { | |
722 | int r; | |
723 | ||
724 | r = misc_register(&_autofs_dev_ioctl_misc); | |
725 | if (r) { | |
726 | pr_err("misc_register failed for control device\n"); | |
727 | return r; | |
728 | } | |
729 | ||
730 | return 0; | |
731 | } | |
732 | ||
733 | void autofs_dev_ioctl_exit(void) | |
734 | { | |
735 | misc_deregister(&_autofs_dev_ioctl_misc); | |
736 | } |