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8d7b48e0 IK |
1 | /* |
2 | * Copyright 2008 Red Hat, Inc. All rights reserved. | |
3 | * Copyright 2008 Ian Kent <raven@themaw.net> | |
4 | * | |
5 | * This file is part of the Linux kernel and is made available under | |
6 | * the terms of the GNU General Public License, version 2, or at your | |
7 | * option, any later version, incorporated herein by reference. | |
8 | */ | |
9 | ||
10 | #include <linux/module.h> | |
11 | #include <linux/vmalloc.h> | |
12 | #include <linux/miscdevice.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/wait.h> | |
15 | #include <linux/namei.h> | |
16 | #include <linux/fcntl.h> | |
17 | #include <linux/file.h> | |
18 | #include <linux/fdtable.h> | |
19 | #include <linux/sched.h> | |
20 | #include <linux/compat.h> | |
21 | #include <linux/syscalls.h> | |
22 | #include <linux/smp_lock.h> | |
23 | #include <linux/magic.h> | |
24 | #include <linux/dcache.h> | |
25 | #include <linux/uaccess.h> | |
26 | ||
27 | #include "autofs_i.h" | |
28 | ||
29 | /* | |
30 | * This module implements an interface for routing autofs ioctl control | |
31 | * commands via a miscellaneous device file. | |
32 | * | |
33 | * The alternate interface is needed because we need to be able open | |
34 | * an ioctl file descriptor on an autofs mount that may be covered by | |
35 | * another mount. This situation arises when starting automount(8) | |
36 | * or other user space daemon which uses direct mounts or offset | |
37 | * mounts (used for autofs lazy mount/umount of nested mount trees), | |
38 | * which have been left busy at at service shutdown. | |
39 | */ | |
40 | ||
41 | #define AUTOFS_DEV_IOCTL_SIZE sizeof(struct autofs_dev_ioctl) | |
42 | ||
43 | typedef int (*ioctl_fn)(struct file *, struct autofs_sb_info *, | |
44 | struct autofs_dev_ioctl *); | |
45 | ||
46 | static int check_name(const char *name) | |
47 | { | |
48 | if (!strchr(name, '/')) | |
49 | return -EINVAL; | |
50 | return 0; | |
51 | } | |
52 | ||
53 | /* | |
54 | * Check a string doesn't overrun the chunk of | |
55 | * memory we copied from user land. | |
56 | */ | |
57 | static int invalid_str(char *str, void *end) | |
58 | { | |
59 | while ((void *) str <= end) | |
60 | if (!*str++) | |
61 | return 0; | |
62 | return -EINVAL; | |
63 | } | |
64 | ||
65 | /* | |
66 | * Check that the user compiled against correct version of autofs | |
67 | * misc device code. | |
68 | * | |
69 | * As well as checking the version compatibility this always copies | |
70 | * the kernel interface version out. | |
71 | */ | |
72 | static int check_dev_ioctl_version(int cmd, struct autofs_dev_ioctl *param) | |
73 | { | |
74 | int err = 0; | |
75 | ||
76 | if ((AUTOFS_DEV_IOCTL_VERSION_MAJOR != param->ver_major) || | |
77 | (AUTOFS_DEV_IOCTL_VERSION_MINOR < param->ver_minor)) { | |
78 | AUTOFS_WARN("ioctl control interface version mismatch: " | |
79 | "kernel(%u.%u), user(%u.%u), cmd(%d)", | |
80 | AUTOFS_DEV_IOCTL_VERSION_MAJOR, | |
81 | AUTOFS_DEV_IOCTL_VERSION_MINOR, | |
82 | param->ver_major, param->ver_minor, cmd); | |
83 | err = -EINVAL; | |
84 | } | |
85 | ||
86 | /* Fill in the kernel version. */ | |
87 | param->ver_major = AUTOFS_DEV_IOCTL_VERSION_MAJOR; | |
88 | param->ver_minor = AUTOFS_DEV_IOCTL_VERSION_MINOR; | |
89 | ||
90 | return err; | |
91 | } | |
92 | ||
93 | /* | |
94 | * Copy parameter control struct, including a possible path allocated | |
95 | * at the end of the struct. | |
96 | */ | |
97 | static struct autofs_dev_ioctl *copy_dev_ioctl(struct autofs_dev_ioctl __user *in) | |
98 | { | |
99 | struct autofs_dev_ioctl tmp, *ads; | |
100 | ||
101 | if (copy_from_user(&tmp, in, sizeof(tmp))) | |
102 | return ERR_PTR(-EFAULT); | |
103 | ||
104 | if (tmp.size < sizeof(tmp)) | |
105 | return ERR_PTR(-EINVAL); | |
106 | ||
107 | ads = kmalloc(tmp.size, GFP_KERNEL); | |
108 | if (!ads) | |
109 | return ERR_PTR(-ENOMEM); | |
110 | ||
111 | if (copy_from_user(ads, in, tmp.size)) { | |
112 | kfree(ads); | |
113 | return ERR_PTR(-EFAULT); | |
114 | } | |
115 | ||
116 | return ads; | |
117 | } | |
118 | ||
119 | static inline void free_dev_ioctl(struct autofs_dev_ioctl *param) | |
120 | { | |
121 | kfree(param); | |
122 | return; | |
123 | } | |
124 | ||
125 | /* | |
126 | * Check sanity of parameter control fields and if a path is present | |
bae8ec66 | 127 | * check that it is terminated and contains at least one "/". |
8d7b48e0 IK |
128 | */ |
129 | static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param) | |
130 | { | |
96b03179 | 131 | int err; |
8d7b48e0 | 132 | |
96b03179 IK |
133 | err = check_dev_ioctl_version(cmd, param); |
134 | if (err) { | |
8d7b48e0 IK |
135 | AUTOFS_WARN("invalid device control module version " |
136 | "supplied for cmd(0x%08x)", cmd); | |
137 | goto out; | |
138 | } | |
139 | ||
140 | if (param->size > sizeof(*param)) { | |
bae8ec66 IK |
141 | err = invalid_str(param->path, |
142 | (void *) ((size_t) param + param->size)); | |
8d7b48e0 | 143 | if (err) { |
bae8ec66 IK |
144 | AUTOFS_WARN( |
145 | "path string terminator missing for cmd(0x%08x)", | |
146 | cmd); | |
8d7b48e0 IK |
147 | goto out; |
148 | } | |
149 | ||
bae8ec66 | 150 | err = check_name(param->path); |
8d7b48e0 IK |
151 | if (err) { |
152 | AUTOFS_WARN("invalid path supplied for cmd(0x%08x)", | |
153 | cmd); | |
154 | goto out; | |
155 | } | |
156 | } | |
157 | ||
158 | err = 0; | |
159 | out: | |
160 | return err; | |
161 | } | |
162 | ||
163 | /* | |
164 | * Get the autofs super block info struct from the file opened on | |
165 | * the autofs mount point. | |
166 | */ | |
167 | static struct autofs_sb_info *autofs_dev_ioctl_sbi(struct file *f) | |
168 | { | |
169 | struct autofs_sb_info *sbi = NULL; | |
170 | struct inode *inode; | |
171 | ||
172 | if (f) { | |
173 | inode = f->f_path.dentry->d_inode; | |
174 | sbi = autofs4_sbi(inode->i_sb); | |
175 | } | |
176 | return sbi; | |
177 | } | |
178 | ||
179 | /* Return autofs module protocol version */ | |
180 | static int autofs_dev_ioctl_protover(struct file *fp, | |
181 | struct autofs_sb_info *sbi, | |
182 | struct autofs_dev_ioctl *param) | |
183 | { | |
730c9eec | 184 | param->protover.version = sbi->version; |
8d7b48e0 IK |
185 | return 0; |
186 | } | |
187 | ||
188 | /* Return autofs module protocol sub version */ | |
189 | static int autofs_dev_ioctl_protosubver(struct file *fp, | |
190 | struct autofs_sb_info *sbi, | |
191 | struct autofs_dev_ioctl *param) | |
192 | { | |
730c9eec | 193 | param->protosubver.sub_version = sbi->sub_version; |
8d7b48e0 IK |
194 | return 0; |
195 | } | |
196 | ||
197 | /* | |
198 | * Walk down the mount stack looking for an autofs mount that | |
199 | * has the requested device number (aka. new_encode_dev(sb->s_dev). | |
200 | */ | |
201 | static int autofs_dev_ioctl_find_super(struct nameidata *nd, dev_t devno) | |
202 | { | |
203 | struct dentry *dentry; | |
204 | struct inode *inode; | |
205 | struct super_block *sb; | |
206 | dev_t s_dev; | |
207 | unsigned int err; | |
208 | ||
209 | err = -ENOENT; | |
210 | ||
211 | /* Lookup the dentry name at the base of our mount point */ | |
212 | dentry = d_lookup(nd->path.dentry, &nd->last); | |
213 | if (!dentry) | |
214 | goto out; | |
215 | ||
216 | dput(nd->path.dentry); | |
217 | nd->path.dentry = dentry; | |
218 | ||
219 | /* And follow the mount stack looking for our autofs mount */ | |
220 | while (follow_down(&nd->path.mnt, &nd->path.dentry)) { | |
221 | inode = nd->path.dentry->d_inode; | |
222 | if (!inode) | |
223 | break; | |
224 | ||
225 | sb = inode->i_sb; | |
226 | s_dev = new_encode_dev(sb->s_dev); | |
227 | if (devno == s_dev) { | |
228 | if (sb->s_magic == AUTOFS_SUPER_MAGIC) { | |
229 | err = 0; | |
230 | break; | |
231 | } | |
232 | } | |
233 | } | |
234 | out: | |
235 | return err; | |
236 | } | |
237 | ||
238 | /* | |
239 | * Walk down the mount stack looking for an autofs mount that | |
240 | * has the requested mount type (ie. indirect, direct or offset). | |
241 | */ | |
242 | static int autofs_dev_ioctl_find_sbi_type(struct nameidata *nd, unsigned int type) | |
243 | { | |
244 | struct dentry *dentry; | |
245 | struct autofs_info *ino; | |
246 | unsigned int err; | |
247 | ||
248 | err = -ENOENT; | |
249 | ||
250 | /* Lookup the dentry name at the base of our mount point */ | |
251 | dentry = d_lookup(nd->path.dentry, &nd->last); | |
252 | if (!dentry) | |
253 | goto out; | |
254 | ||
255 | dput(nd->path.dentry); | |
256 | nd->path.dentry = dentry; | |
257 | ||
258 | /* And follow the mount stack looking for our autofs mount */ | |
259 | while (follow_down(&nd->path.mnt, &nd->path.dentry)) { | |
260 | ino = autofs4_dentry_ino(nd->path.dentry); | |
261 | if (ino && ino->sbi->type & type) { | |
262 | err = 0; | |
263 | break; | |
264 | } | |
265 | } | |
266 | out: | |
267 | return err; | |
268 | } | |
269 | ||
270 | static void autofs_dev_ioctl_fd_install(unsigned int fd, struct file *file) | |
271 | { | |
272 | struct files_struct *files = current->files; | |
273 | struct fdtable *fdt; | |
274 | ||
275 | spin_lock(&files->file_lock); | |
276 | fdt = files_fdtable(files); | |
277 | BUG_ON(fdt->fd[fd] != NULL); | |
278 | rcu_assign_pointer(fdt->fd[fd], file); | |
279 | FD_SET(fd, fdt->close_on_exec); | |
280 | spin_unlock(&files->file_lock); | |
281 | } | |
282 | ||
283 | ||
284 | /* | |
285 | * Open a file descriptor on the autofs mount point corresponding | |
286 | * to the given path and device number (aka. new_encode_dev(sb->s_dev)). | |
287 | */ | |
288 | static int autofs_dev_ioctl_open_mountpoint(const char *path, dev_t devid) | |
289 | { | |
290 | struct file *filp; | |
291 | struct nameidata nd; | |
292 | int err, fd; | |
293 | ||
294 | fd = get_unused_fd(); | |
295 | if (likely(fd >= 0)) { | |
296 | /* Get nameidata of the parent directory */ | |
297 | err = path_lookup(path, LOOKUP_PARENT, &nd); | |
298 | if (err) | |
299 | goto out; | |
300 | ||
301 | /* | |
302 | * Search down, within the parent, looking for an | |
303 | * autofs super block that has the device number | |
304 | * corresponding to the autofs fs we want to open. | |
305 | */ | |
306 | err = autofs_dev_ioctl_find_super(&nd, devid); | |
307 | if (err) { | |
308 | path_put(&nd.path); | |
309 | goto out; | |
310 | } | |
311 | ||
745ca247 DH |
312 | filp = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY, |
313 | current_cred()); | |
8d7b48e0 IK |
314 | if (IS_ERR(filp)) { |
315 | err = PTR_ERR(filp); | |
316 | goto out; | |
317 | } | |
318 | ||
319 | autofs_dev_ioctl_fd_install(fd, filp); | |
320 | } | |
321 | ||
322 | return fd; | |
323 | ||
324 | out: | |
325 | put_unused_fd(fd); | |
326 | return err; | |
327 | } | |
328 | ||
329 | /* Open a file descriptor on an autofs mount point */ | |
330 | static int autofs_dev_ioctl_openmount(struct file *fp, | |
331 | struct autofs_sb_info *sbi, | |
332 | struct autofs_dev_ioctl *param) | |
333 | { | |
334 | const char *path; | |
335 | dev_t devid; | |
336 | int err, fd; | |
337 | ||
338 | /* param->path has already been checked */ | |
730c9eec | 339 | if (!param->openmount.devid) |
8d7b48e0 IK |
340 | return -EINVAL; |
341 | ||
342 | param->ioctlfd = -1; | |
343 | ||
344 | path = param->path; | |
730c9eec | 345 | devid = param->openmount.devid; |
8d7b48e0 IK |
346 | |
347 | err = 0; | |
348 | fd = autofs_dev_ioctl_open_mountpoint(path, devid); | |
349 | if (unlikely(fd < 0)) { | |
350 | err = fd; | |
351 | goto out; | |
352 | } | |
353 | ||
354 | param->ioctlfd = fd; | |
355 | out: | |
356 | return err; | |
357 | } | |
358 | ||
359 | /* Close file descriptor allocated above (user can also use close(2)). */ | |
360 | static int autofs_dev_ioctl_closemount(struct file *fp, | |
361 | struct autofs_sb_info *sbi, | |
362 | struct autofs_dev_ioctl *param) | |
363 | { | |
364 | return sys_close(param->ioctlfd); | |
365 | } | |
366 | ||
367 | /* | |
368 | * Send "ready" status for an existing wait (either a mount or an expire | |
369 | * request). | |
370 | */ | |
371 | static int autofs_dev_ioctl_ready(struct file *fp, | |
372 | struct autofs_sb_info *sbi, | |
373 | struct autofs_dev_ioctl *param) | |
374 | { | |
375 | autofs_wqt_t token; | |
376 | ||
730c9eec | 377 | token = (autofs_wqt_t) param->ready.token; |
8d7b48e0 IK |
378 | return autofs4_wait_release(sbi, token, 0); |
379 | } | |
380 | ||
381 | /* | |
382 | * Send "fail" status for an existing wait (either a mount or an expire | |
383 | * request). | |
384 | */ | |
385 | static int autofs_dev_ioctl_fail(struct file *fp, | |
386 | struct autofs_sb_info *sbi, | |
387 | struct autofs_dev_ioctl *param) | |
388 | { | |
389 | autofs_wqt_t token; | |
390 | int status; | |
391 | ||
730c9eec IK |
392 | token = (autofs_wqt_t) param->fail.token; |
393 | status = param->fail.status ? param->fail.status : -ENOENT; | |
8d7b48e0 IK |
394 | return autofs4_wait_release(sbi, token, status); |
395 | } | |
396 | ||
397 | /* | |
398 | * Set the pipe fd for kernel communication to the daemon. | |
399 | * | |
400 | * Normally this is set at mount using an option but if we | |
401 | * are reconnecting to a busy mount then we need to use this | |
402 | * to tell the autofs mount about the new kernel pipe fd. In | |
403 | * order to protect mounts against incorrectly setting the | |
404 | * pipefd we also require that the autofs mount be catatonic. | |
405 | * | |
406 | * This also sets the process group id used to identify the | |
407 | * controlling process (eg. the owning automount(8) daemon). | |
408 | */ | |
409 | static int autofs_dev_ioctl_setpipefd(struct file *fp, | |
410 | struct autofs_sb_info *sbi, | |
411 | struct autofs_dev_ioctl *param) | |
412 | { | |
413 | int pipefd; | |
414 | int err = 0; | |
415 | ||
730c9eec | 416 | if (param->setpipefd.pipefd == -1) |
8d7b48e0 IK |
417 | return -EINVAL; |
418 | ||
730c9eec | 419 | pipefd = param->setpipefd.pipefd; |
8d7b48e0 IK |
420 | |
421 | mutex_lock(&sbi->wq_mutex); | |
422 | if (!sbi->catatonic) { | |
423 | mutex_unlock(&sbi->wq_mutex); | |
424 | return -EBUSY; | |
425 | } else { | |
426 | struct file *pipe = fget(pipefd); | |
427 | if (!pipe->f_op || !pipe->f_op->write) { | |
428 | err = -EPIPE; | |
429 | fput(pipe); | |
430 | goto out; | |
431 | } | |
432 | sbi->oz_pgrp = task_pgrp_nr(current); | |
433 | sbi->pipefd = pipefd; | |
434 | sbi->pipe = pipe; | |
435 | sbi->catatonic = 0; | |
436 | } | |
437 | out: | |
438 | mutex_unlock(&sbi->wq_mutex); | |
439 | return err; | |
440 | } | |
441 | ||
442 | /* | |
443 | * Make the autofs mount point catatonic, no longer responsive to | |
444 | * mount requests. Also closes the kernel pipe file descriptor. | |
445 | */ | |
446 | static int autofs_dev_ioctl_catatonic(struct file *fp, | |
447 | struct autofs_sb_info *sbi, | |
448 | struct autofs_dev_ioctl *param) | |
449 | { | |
450 | autofs4_catatonic_mode(sbi); | |
451 | return 0; | |
452 | } | |
453 | ||
454 | /* Set the autofs mount timeout */ | |
455 | static int autofs_dev_ioctl_timeout(struct file *fp, | |
456 | struct autofs_sb_info *sbi, | |
457 | struct autofs_dev_ioctl *param) | |
458 | { | |
459 | unsigned long timeout; | |
460 | ||
730c9eec IK |
461 | timeout = param->timeout.timeout; |
462 | param->timeout.timeout = sbi->exp_timeout / HZ; | |
8d7b48e0 IK |
463 | sbi->exp_timeout = timeout * HZ; |
464 | return 0; | |
465 | } | |
466 | ||
467 | /* | |
468 | * Return the uid and gid of the last request for the mount | |
469 | * | |
470 | * When reconstructing an autofs mount tree with active mounts | |
471 | * we need to re-connect to mounts that may have used the original | |
472 | * process uid and gid (or string variations of them) for mount | |
473 | * lookups within the map entry. | |
474 | */ | |
475 | static int autofs_dev_ioctl_requester(struct file *fp, | |
476 | struct autofs_sb_info *sbi, | |
477 | struct autofs_dev_ioctl *param) | |
478 | { | |
479 | struct autofs_info *ino; | |
480 | struct nameidata nd; | |
481 | const char *path; | |
482 | dev_t devid; | |
483 | int err = -ENOENT; | |
484 | ||
485 | if (param->size <= sizeof(*param)) { | |
486 | err = -EINVAL; | |
487 | goto out; | |
488 | } | |
489 | ||
490 | path = param->path; | |
491 | devid = sbi->sb->s_dev; | |
492 | ||
730c9eec | 493 | param->requester.uid = param->requester.gid = -1; |
8d7b48e0 IK |
494 | |
495 | /* Get nameidata of the parent directory */ | |
496 | err = path_lookup(path, LOOKUP_PARENT, &nd); | |
497 | if (err) | |
498 | goto out; | |
499 | ||
500 | err = autofs_dev_ioctl_find_super(&nd, devid); | |
501 | if (err) | |
502 | goto out_release; | |
503 | ||
504 | ino = autofs4_dentry_ino(nd.path.dentry); | |
505 | if (ino) { | |
506 | err = 0; | |
507 | autofs4_expire_wait(nd.path.dentry); | |
508 | spin_lock(&sbi->fs_lock); | |
730c9eec IK |
509 | param->requester.uid = ino->uid; |
510 | param->requester.gid = ino->gid; | |
8d7b48e0 IK |
511 | spin_unlock(&sbi->fs_lock); |
512 | } | |
513 | ||
514 | out_release: | |
515 | path_put(&nd.path); | |
516 | out: | |
517 | return err; | |
518 | } | |
519 | ||
520 | /* | |
521 | * Call repeatedly until it returns -EAGAIN, meaning there's nothing | |
522 | * more that can be done. | |
523 | */ | |
524 | static int autofs_dev_ioctl_expire(struct file *fp, | |
525 | struct autofs_sb_info *sbi, | |
526 | struct autofs_dev_ioctl *param) | |
527 | { | |
528 | struct dentry *dentry; | |
529 | struct vfsmount *mnt; | |
530 | int err = -EAGAIN; | |
531 | int how; | |
532 | ||
730c9eec | 533 | how = param->expire.how; |
8d7b48e0 IK |
534 | mnt = fp->f_path.mnt; |
535 | ||
a92daf6b | 536 | if (autofs_type_trigger(sbi->type)) |
8d7b48e0 IK |
537 | dentry = autofs4_expire_direct(sbi->sb, mnt, sbi, how); |
538 | else | |
539 | dentry = autofs4_expire_indirect(sbi->sb, mnt, sbi, how); | |
540 | ||
541 | if (dentry) { | |
542 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
543 | ||
544 | /* | |
545 | * This is synchronous because it makes the daemon a | |
546 | * little easier | |
547 | */ | |
548 | err = autofs4_wait(sbi, dentry, NFY_EXPIRE); | |
549 | ||
550 | spin_lock(&sbi->fs_lock); | |
551 | if (ino->flags & AUTOFS_INF_MOUNTPOINT) { | |
552 | ino->flags &= ~AUTOFS_INF_MOUNTPOINT; | |
553 | sbi->sb->s_root->d_mounted++; | |
554 | } | |
555 | ino->flags &= ~AUTOFS_INF_EXPIRING; | |
556 | complete_all(&ino->expire_complete); | |
557 | spin_unlock(&sbi->fs_lock); | |
558 | dput(dentry); | |
559 | } | |
560 | ||
561 | return err; | |
562 | } | |
563 | ||
564 | /* Check if autofs mount point is in use */ | |
565 | static int autofs_dev_ioctl_askumount(struct file *fp, | |
566 | struct autofs_sb_info *sbi, | |
567 | struct autofs_dev_ioctl *param) | |
568 | { | |
730c9eec | 569 | param->askumount.may_umount = 0; |
8d7b48e0 | 570 | if (may_umount(fp->f_path.mnt)) |
730c9eec | 571 | param->askumount.may_umount = 1; |
8d7b48e0 IK |
572 | return 0; |
573 | } | |
574 | ||
575 | /* | |
576 | * Check if the given path is a mountpoint. | |
577 | * | |
578 | * If we are supplied with the file descriptor of an autofs | |
579 | * mount we're looking for a specific mount. In this case | |
580 | * the path is considered a mountpoint if it is itself a | |
581 | * mountpoint or contains a mount, such as a multi-mount | |
582 | * without a root mount. In this case we return 1 if the | |
583 | * path is a mount point and the super magic of the covering | |
584 | * mount if there is one or 0 if it isn't a mountpoint. | |
585 | * | |
586 | * If we aren't supplied with a file descriptor then we | |
587 | * lookup the nameidata of the path and check if it is the | |
588 | * root of a mount. If a type is given we are looking for | |
589 | * a particular autofs mount and if we don't find a match | |
590 | * we return fail. If the located nameidata path is the | |
591 | * root of a mount we return 1 along with the super magic | |
592 | * of the mount or 0 otherwise. | |
593 | * | |
594 | * In both cases the the device number (as returned by | |
595 | * new_encode_dev()) is also returned. | |
596 | */ | |
597 | static int autofs_dev_ioctl_ismountpoint(struct file *fp, | |
598 | struct autofs_sb_info *sbi, | |
599 | struct autofs_dev_ioctl *param) | |
600 | { | |
601 | struct nameidata nd; | |
602 | const char *path; | |
603 | unsigned int type; | |
730c9eec | 604 | unsigned int devid, magic; |
8d7b48e0 IK |
605 | int err = -ENOENT; |
606 | ||
607 | if (param->size <= sizeof(*param)) { | |
608 | err = -EINVAL; | |
609 | goto out; | |
610 | } | |
611 | ||
612 | path = param->path; | |
730c9eec | 613 | type = param->ismountpoint.in.type; |
8d7b48e0 | 614 | |
730c9eec IK |
615 | param->ismountpoint.out.devid = devid = 0; |
616 | param->ismountpoint.out.magic = magic = 0; | |
8d7b48e0 IK |
617 | |
618 | if (!fp || param->ioctlfd == -1) { | |
a92daf6b | 619 | if (autofs_type_any(type)) { |
8d7b48e0 IK |
620 | struct super_block *sb; |
621 | ||
622 | err = path_lookup(path, LOOKUP_FOLLOW, &nd); | |
623 | if (err) | |
624 | goto out; | |
625 | ||
626 | sb = nd.path.dentry->d_sb; | |
730c9eec | 627 | devid = new_encode_dev(sb->s_dev); |
8d7b48e0 IK |
628 | } else { |
629 | struct autofs_info *ino; | |
630 | ||
631 | err = path_lookup(path, LOOKUP_PARENT, &nd); | |
632 | if (err) | |
633 | goto out; | |
634 | ||
635 | err = autofs_dev_ioctl_find_sbi_type(&nd, type); | |
636 | if (err) | |
637 | goto out_release; | |
638 | ||
639 | ino = autofs4_dentry_ino(nd.path.dentry); | |
730c9eec | 640 | devid = autofs4_get_dev(ino->sbi); |
8d7b48e0 IK |
641 | } |
642 | ||
643 | err = 0; | |
644 | if (nd.path.dentry->d_inode && | |
645 | nd.path.mnt->mnt_root == nd.path.dentry) { | |
646 | err = 1; | |
730c9eec | 647 | magic = nd.path.dentry->d_inode->i_sb->s_magic; |
8d7b48e0 IK |
648 | } |
649 | } else { | |
41cfef2e | 650 | dev_t dev = autofs4_get_dev(sbi); |
8d7b48e0 IK |
651 | |
652 | err = path_lookup(path, LOOKUP_PARENT, &nd); | |
653 | if (err) | |
654 | goto out; | |
655 | ||
41cfef2e | 656 | err = autofs_dev_ioctl_find_super(&nd, dev); |
8d7b48e0 IK |
657 | if (err) |
658 | goto out_release; | |
659 | ||
41cfef2e | 660 | devid = dev; |
8d7b48e0 IK |
661 | |
662 | err = have_submounts(nd.path.dentry); | |
663 | ||
664 | if (nd.path.mnt->mnt_mountpoint != nd.path.mnt->mnt_root) { | |
665 | if (follow_down(&nd.path.mnt, &nd.path.dentry)) { | |
666 | struct inode *inode = nd.path.dentry->d_inode; | |
730c9eec | 667 | magic = inode->i_sb->s_magic; |
8d7b48e0 IK |
668 | } |
669 | } | |
670 | } | |
671 | ||
730c9eec IK |
672 | param->ismountpoint.out.devid = devid; |
673 | param->ismountpoint.out.magic = magic; | |
674 | ||
8d7b48e0 IK |
675 | out_release: |
676 | path_put(&nd.path); | |
677 | out: | |
678 | return err; | |
679 | } | |
680 | ||
681 | /* | |
682 | * Our range of ioctl numbers isn't 0 based so we need to shift | |
683 | * the array index by _IOC_NR(AUTOFS_CTL_IOC_FIRST) for the table | |
684 | * lookup. | |
685 | */ | |
686 | #define cmd_idx(cmd) (cmd - _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST)) | |
687 | ||
688 | static ioctl_fn lookup_dev_ioctl(unsigned int cmd) | |
689 | { | |
690 | static struct { | |
691 | int cmd; | |
692 | ioctl_fn fn; | |
693 | } _ioctls[] = { | |
694 | {cmd_idx(AUTOFS_DEV_IOCTL_VERSION_CMD), NULL}, | |
695 | {cmd_idx(AUTOFS_DEV_IOCTL_PROTOVER_CMD), | |
696 | autofs_dev_ioctl_protover}, | |
697 | {cmd_idx(AUTOFS_DEV_IOCTL_PROTOSUBVER_CMD), | |
698 | autofs_dev_ioctl_protosubver}, | |
699 | {cmd_idx(AUTOFS_DEV_IOCTL_OPENMOUNT_CMD), | |
700 | autofs_dev_ioctl_openmount}, | |
701 | {cmd_idx(AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD), | |
702 | autofs_dev_ioctl_closemount}, | |
703 | {cmd_idx(AUTOFS_DEV_IOCTL_READY_CMD), | |
704 | autofs_dev_ioctl_ready}, | |
705 | {cmd_idx(AUTOFS_DEV_IOCTL_FAIL_CMD), | |
706 | autofs_dev_ioctl_fail}, | |
707 | {cmd_idx(AUTOFS_DEV_IOCTL_SETPIPEFD_CMD), | |
708 | autofs_dev_ioctl_setpipefd}, | |
709 | {cmd_idx(AUTOFS_DEV_IOCTL_CATATONIC_CMD), | |
710 | autofs_dev_ioctl_catatonic}, | |
711 | {cmd_idx(AUTOFS_DEV_IOCTL_TIMEOUT_CMD), | |
712 | autofs_dev_ioctl_timeout}, | |
713 | {cmd_idx(AUTOFS_DEV_IOCTL_REQUESTER_CMD), | |
714 | autofs_dev_ioctl_requester}, | |
715 | {cmd_idx(AUTOFS_DEV_IOCTL_EXPIRE_CMD), | |
716 | autofs_dev_ioctl_expire}, | |
717 | {cmd_idx(AUTOFS_DEV_IOCTL_ASKUMOUNT_CMD), | |
718 | autofs_dev_ioctl_askumount}, | |
719 | {cmd_idx(AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD), | |
720 | autofs_dev_ioctl_ismountpoint} | |
721 | }; | |
722 | unsigned int idx = cmd_idx(cmd); | |
723 | ||
724 | return (idx >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[idx].fn; | |
725 | } | |
726 | ||
727 | /* ioctl dispatcher */ | |
728 | static int _autofs_dev_ioctl(unsigned int command, struct autofs_dev_ioctl __user *user) | |
729 | { | |
730 | struct autofs_dev_ioctl *param; | |
731 | struct file *fp; | |
732 | struct autofs_sb_info *sbi; | |
733 | unsigned int cmd_first, cmd; | |
734 | ioctl_fn fn = NULL; | |
735 | int err = 0; | |
736 | ||
737 | /* only root can play with this */ | |
738 | if (!capable(CAP_SYS_ADMIN)) | |
739 | return -EPERM; | |
740 | ||
741 | cmd_first = _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST); | |
742 | cmd = _IOC_NR(command); | |
743 | ||
744 | if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) || | |
745 | cmd - cmd_first >= AUTOFS_DEV_IOCTL_IOC_COUNT) { | |
746 | return -ENOTTY; | |
747 | } | |
748 | ||
749 | /* Copy the parameters into kernel space. */ | |
750 | param = copy_dev_ioctl(user); | |
751 | if (IS_ERR(param)) | |
752 | return PTR_ERR(param); | |
753 | ||
754 | err = validate_dev_ioctl(command, param); | |
755 | if (err) | |
756 | goto out; | |
757 | ||
758 | /* The validate routine above always sets the version */ | |
759 | if (cmd == AUTOFS_DEV_IOCTL_VERSION_CMD) | |
760 | goto done; | |
761 | ||
762 | fn = lookup_dev_ioctl(cmd); | |
763 | if (!fn) { | |
764 | AUTOFS_WARN("unknown command 0x%08x", command); | |
765 | return -ENOTTY; | |
766 | } | |
767 | ||
768 | fp = NULL; | |
769 | sbi = NULL; | |
770 | ||
771 | /* | |
772 | * For obvious reasons the openmount can't have a file | |
773 | * descriptor yet. We don't take a reference to the | |
774 | * file during close to allow for immediate release. | |
775 | */ | |
776 | if (cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD && | |
777 | cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) { | |
778 | fp = fget(param->ioctlfd); | |
779 | if (!fp) { | |
780 | if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) | |
781 | goto cont; | |
782 | err = -EBADF; | |
783 | goto out; | |
784 | } | |
785 | ||
786 | if (!fp->f_op) { | |
787 | err = -ENOTTY; | |
788 | fput(fp); | |
789 | goto out; | |
790 | } | |
791 | ||
792 | sbi = autofs_dev_ioctl_sbi(fp); | |
793 | if (!sbi || sbi->magic != AUTOFS_SBI_MAGIC) { | |
794 | err = -EINVAL; | |
795 | fput(fp); | |
796 | goto out; | |
797 | } | |
798 | ||
799 | /* | |
800 | * Admin needs to be able to set the mount catatonic in | |
801 | * order to be able to perform the re-open. | |
802 | */ | |
803 | if (!autofs4_oz_mode(sbi) && | |
804 | cmd != AUTOFS_DEV_IOCTL_CATATONIC_CMD) { | |
805 | err = -EACCES; | |
806 | fput(fp); | |
807 | goto out; | |
808 | } | |
809 | } | |
810 | cont: | |
811 | err = fn(fp, sbi, param); | |
812 | ||
813 | if (fp) | |
814 | fput(fp); | |
815 | done: | |
816 | if (err >= 0 && copy_to_user(user, param, AUTOFS_DEV_IOCTL_SIZE)) | |
817 | err = -EFAULT; | |
818 | out: | |
819 | free_dev_ioctl(param); | |
820 | return err; | |
821 | } | |
822 | ||
823 | static long autofs_dev_ioctl(struct file *file, uint command, ulong u) | |
824 | { | |
825 | int err; | |
826 | err = _autofs_dev_ioctl(command, (struct autofs_dev_ioctl __user *) u); | |
827 | return (long) err; | |
828 | } | |
829 | ||
830 | #ifdef CONFIG_COMPAT | |
831 | static long autofs_dev_ioctl_compat(struct file *file, uint command, ulong u) | |
832 | { | |
833 | return (long) autofs_dev_ioctl(file, command, (ulong) compat_ptr(u)); | |
834 | } | |
835 | #else | |
836 | #define autofs_dev_ioctl_compat NULL | |
837 | #endif | |
838 | ||
839 | static const struct file_operations _dev_ioctl_fops = { | |
840 | .unlocked_ioctl = autofs_dev_ioctl, | |
841 | .compat_ioctl = autofs_dev_ioctl_compat, | |
842 | .owner = THIS_MODULE, | |
843 | }; | |
844 | ||
845 | static struct miscdevice _autofs_dev_ioctl_misc = { | |
846 | .minor = MISC_DYNAMIC_MINOR, | |
847 | .name = AUTOFS_DEVICE_NAME, | |
848 | .fops = &_dev_ioctl_fops | |
849 | }; | |
850 | ||
851 | /* Register/deregister misc character device */ | |
852 | int autofs_dev_ioctl_init(void) | |
853 | { | |
854 | int r; | |
855 | ||
856 | r = misc_register(&_autofs_dev_ioctl_misc); | |
857 | if (r) { | |
858 | AUTOFS_ERROR("misc_register failed for control device"); | |
859 | return r; | |
860 | } | |
861 | ||
862 | return 0; | |
863 | } | |
864 | ||
865 | void autofs_dev_ioctl_exit(void) | |
866 | { | |
867 | misc_deregister(&_autofs_dev_ioctl_misc); | |
868 | return; | |
869 | } | |
870 |