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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 | |
127 | * check that it has a "/" and is terminated. | |
128 | */ | |
129 | static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param) | |
130 | { | |
131 | int err = -EINVAL; | |
132 | ||
133 | if (check_dev_ioctl_version(cmd, param)) { | |
134 | AUTOFS_WARN("invalid device control module version " | |
135 | "supplied for cmd(0x%08x)", cmd); | |
136 | goto out; | |
137 | } | |
138 | ||
139 | if (param->size > sizeof(*param)) { | |
140 | err = check_name(param->path); | |
141 | if (err) { | |
142 | AUTOFS_WARN("invalid path supplied for cmd(0x%08x)", | |
143 | cmd); | |
144 | goto out; | |
145 | } | |
146 | ||
147 | err = invalid_str(param->path, | |
148 | (void *) ((size_t) param + param->size)); | |
149 | if (err) { | |
150 | AUTOFS_WARN("invalid path supplied for cmd(0x%08x)", | |
151 | cmd); | |
152 | goto out; | |
153 | } | |
154 | } | |
155 | ||
156 | err = 0; | |
157 | out: | |
158 | return err; | |
159 | } | |
160 | ||
161 | /* | |
162 | * Get the autofs super block info struct from the file opened on | |
163 | * the autofs mount point. | |
164 | */ | |
165 | static struct autofs_sb_info *autofs_dev_ioctl_sbi(struct file *f) | |
166 | { | |
167 | struct autofs_sb_info *sbi = NULL; | |
168 | struct inode *inode; | |
169 | ||
170 | if (f) { | |
171 | inode = f->f_path.dentry->d_inode; | |
172 | sbi = autofs4_sbi(inode->i_sb); | |
173 | } | |
174 | return sbi; | |
175 | } | |
176 | ||
177 | /* Return autofs module protocol version */ | |
178 | static int autofs_dev_ioctl_protover(struct file *fp, | |
179 | struct autofs_sb_info *sbi, | |
180 | struct autofs_dev_ioctl *param) | |
181 | { | |
182 | param->arg1 = sbi->version; | |
183 | return 0; | |
184 | } | |
185 | ||
186 | /* Return autofs module protocol sub version */ | |
187 | static int autofs_dev_ioctl_protosubver(struct file *fp, | |
188 | struct autofs_sb_info *sbi, | |
189 | struct autofs_dev_ioctl *param) | |
190 | { | |
191 | param->arg1 = sbi->sub_version; | |
192 | return 0; | |
193 | } | |
194 | ||
195 | /* | |
196 | * Walk down the mount stack looking for an autofs mount that | |
197 | * has the requested device number (aka. new_encode_dev(sb->s_dev). | |
198 | */ | |
199 | static int autofs_dev_ioctl_find_super(struct nameidata *nd, dev_t devno) | |
200 | { | |
201 | struct dentry *dentry; | |
202 | struct inode *inode; | |
203 | struct super_block *sb; | |
204 | dev_t s_dev; | |
205 | unsigned int err; | |
206 | ||
207 | err = -ENOENT; | |
208 | ||
209 | /* Lookup the dentry name at the base of our mount point */ | |
210 | dentry = d_lookup(nd->path.dentry, &nd->last); | |
211 | if (!dentry) | |
212 | goto out; | |
213 | ||
214 | dput(nd->path.dentry); | |
215 | nd->path.dentry = dentry; | |
216 | ||
217 | /* And follow the mount stack looking for our autofs mount */ | |
218 | while (follow_down(&nd->path.mnt, &nd->path.dentry)) { | |
219 | inode = nd->path.dentry->d_inode; | |
220 | if (!inode) | |
221 | break; | |
222 | ||
223 | sb = inode->i_sb; | |
224 | s_dev = new_encode_dev(sb->s_dev); | |
225 | if (devno == s_dev) { | |
226 | if (sb->s_magic == AUTOFS_SUPER_MAGIC) { | |
227 | err = 0; | |
228 | break; | |
229 | } | |
230 | } | |
231 | } | |
232 | out: | |
233 | return err; | |
234 | } | |
235 | ||
236 | /* | |
237 | * Walk down the mount stack looking for an autofs mount that | |
238 | * has the requested mount type (ie. indirect, direct or offset). | |
239 | */ | |
240 | static int autofs_dev_ioctl_find_sbi_type(struct nameidata *nd, unsigned int type) | |
241 | { | |
242 | struct dentry *dentry; | |
243 | struct autofs_info *ino; | |
244 | unsigned int err; | |
245 | ||
246 | err = -ENOENT; | |
247 | ||
248 | /* Lookup the dentry name at the base of our mount point */ | |
249 | dentry = d_lookup(nd->path.dentry, &nd->last); | |
250 | if (!dentry) | |
251 | goto out; | |
252 | ||
253 | dput(nd->path.dentry); | |
254 | nd->path.dentry = dentry; | |
255 | ||
256 | /* And follow the mount stack looking for our autofs mount */ | |
257 | while (follow_down(&nd->path.mnt, &nd->path.dentry)) { | |
258 | ino = autofs4_dentry_ino(nd->path.dentry); | |
259 | if (ino && ino->sbi->type & type) { | |
260 | err = 0; | |
261 | break; | |
262 | } | |
263 | } | |
264 | out: | |
265 | return err; | |
266 | } | |
267 | ||
268 | static void autofs_dev_ioctl_fd_install(unsigned int fd, struct file *file) | |
269 | { | |
270 | struct files_struct *files = current->files; | |
271 | struct fdtable *fdt; | |
272 | ||
273 | spin_lock(&files->file_lock); | |
274 | fdt = files_fdtable(files); | |
275 | BUG_ON(fdt->fd[fd] != NULL); | |
276 | rcu_assign_pointer(fdt->fd[fd], file); | |
277 | FD_SET(fd, fdt->close_on_exec); | |
278 | spin_unlock(&files->file_lock); | |
279 | } | |
280 | ||
281 | ||
282 | /* | |
283 | * Open a file descriptor on the autofs mount point corresponding | |
284 | * to the given path and device number (aka. new_encode_dev(sb->s_dev)). | |
285 | */ | |
286 | static int autofs_dev_ioctl_open_mountpoint(const char *path, dev_t devid) | |
287 | { | |
288 | struct file *filp; | |
289 | struct nameidata nd; | |
290 | int err, fd; | |
291 | ||
292 | fd = get_unused_fd(); | |
293 | if (likely(fd >= 0)) { | |
294 | /* Get nameidata of the parent directory */ | |
295 | err = path_lookup(path, LOOKUP_PARENT, &nd); | |
296 | if (err) | |
297 | goto out; | |
298 | ||
299 | /* | |
300 | * Search down, within the parent, looking for an | |
301 | * autofs super block that has the device number | |
302 | * corresponding to the autofs fs we want to open. | |
303 | */ | |
304 | err = autofs_dev_ioctl_find_super(&nd, devid); | |
305 | if (err) { | |
306 | path_put(&nd.path); | |
307 | goto out; | |
308 | } | |
309 | ||
310 | filp = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY); | |
311 | if (IS_ERR(filp)) { | |
312 | err = PTR_ERR(filp); | |
313 | goto out; | |
314 | } | |
315 | ||
316 | autofs_dev_ioctl_fd_install(fd, filp); | |
317 | } | |
318 | ||
319 | return fd; | |
320 | ||
321 | out: | |
322 | put_unused_fd(fd); | |
323 | return err; | |
324 | } | |
325 | ||
326 | /* Open a file descriptor on an autofs mount point */ | |
327 | static int autofs_dev_ioctl_openmount(struct file *fp, | |
328 | struct autofs_sb_info *sbi, | |
329 | struct autofs_dev_ioctl *param) | |
330 | { | |
331 | const char *path; | |
332 | dev_t devid; | |
333 | int err, fd; | |
334 | ||
335 | /* param->path has already been checked */ | |
336 | if (!param->arg1) | |
337 | return -EINVAL; | |
338 | ||
339 | param->ioctlfd = -1; | |
340 | ||
341 | path = param->path; | |
342 | devid = param->arg1; | |
343 | ||
344 | err = 0; | |
345 | fd = autofs_dev_ioctl_open_mountpoint(path, devid); | |
346 | if (unlikely(fd < 0)) { | |
347 | err = fd; | |
348 | goto out; | |
349 | } | |
350 | ||
351 | param->ioctlfd = fd; | |
352 | out: | |
353 | return err; | |
354 | } | |
355 | ||
356 | /* Close file descriptor allocated above (user can also use close(2)). */ | |
357 | static int autofs_dev_ioctl_closemount(struct file *fp, | |
358 | struct autofs_sb_info *sbi, | |
359 | struct autofs_dev_ioctl *param) | |
360 | { | |
361 | return sys_close(param->ioctlfd); | |
362 | } | |
363 | ||
364 | /* | |
365 | * Send "ready" status for an existing wait (either a mount or an expire | |
366 | * request). | |
367 | */ | |
368 | static int autofs_dev_ioctl_ready(struct file *fp, | |
369 | struct autofs_sb_info *sbi, | |
370 | struct autofs_dev_ioctl *param) | |
371 | { | |
372 | autofs_wqt_t token; | |
373 | ||
374 | token = (autofs_wqt_t) param->arg1; | |
375 | return autofs4_wait_release(sbi, token, 0); | |
376 | } | |
377 | ||
378 | /* | |
379 | * Send "fail" status for an existing wait (either a mount or an expire | |
380 | * request). | |
381 | */ | |
382 | static int autofs_dev_ioctl_fail(struct file *fp, | |
383 | struct autofs_sb_info *sbi, | |
384 | struct autofs_dev_ioctl *param) | |
385 | { | |
386 | autofs_wqt_t token; | |
387 | int status; | |
388 | ||
389 | token = (autofs_wqt_t) param->arg1; | |
390 | status = param->arg2 ? param->arg2 : -ENOENT; | |
391 | return autofs4_wait_release(sbi, token, status); | |
392 | } | |
393 | ||
394 | /* | |
395 | * Set the pipe fd for kernel communication to the daemon. | |
396 | * | |
397 | * Normally this is set at mount using an option but if we | |
398 | * are reconnecting to a busy mount then we need to use this | |
399 | * to tell the autofs mount about the new kernel pipe fd. In | |
400 | * order to protect mounts against incorrectly setting the | |
401 | * pipefd we also require that the autofs mount be catatonic. | |
402 | * | |
403 | * This also sets the process group id used to identify the | |
404 | * controlling process (eg. the owning automount(8) daemon). | |
405 | */ | |
406 | static int autofs_dev_ioctl_setpipefd(struct file *fp, | |
407 | struct autofs_sb_info *sbi, | |
408 | struct autofs_dev_ioctl *param) | |
409 | { | |
410 | int pipefd; | |
411 | int err = 0; | |
412 | ||
413 | if (param->arg1 == -1) | |
414 | return -EINVAL; | |
415 | ||
416 | pipefd = param->arg1; | |
417 | ||
418 | mutex_lock(&sbi->wq_mutex); | |
419 | if (!sbi->catatonic) { | |
420 | mutex_unlock(&sbi->wq_mutex); | |
421 | return -EBUSY; | |
422 | } else { | |
423 | struct file *pipe = fget(pipefd); | |
424 | if (!pipe->f_op || !pipe->f_op->write) { | |
425 | err = -EPIPE; | |
426 | fput(pipe); | |
427 | goto out; | |
428 | } | |
429 | sbi->oz_pgrp = task_pgrp_nr(current); | |
430 | sbi->pipefd = pipefd; | |
431 | sbi->pipe = pipe; | |
432 | sbi->catatonic = 0; | |
433 | } | |
434 | out: | |
435 | mutex_unlock(&sbi->wq_mutex); | |
436 | return err; | |
437 | } | |
438 | ||
439 | /* | |
440 | * Make the autofs mount point catatonic, no longer responsive to | |
441 | * mount requests. Also closes the kernel pipe file descriptor. | |
442 | */ | |
443 | static int autofs_dev_ioctl_catatonic(struct file *fp, | |
444 | struct autofs_sb_info *sbi, | |
445 | struct autofs_dev_ioctl *param) | |
446 | { | |
447 | autofs4_catatonic_mode(sbi); | |
448 | return 0; | |
449 | } | |
450 | ||
451 | /* Set the autofs mount timeout */ | |
452 | static int autofs_dev_ioctl_timeout(struct file *fp, | |
453 | struct autofs_sb_info *sbi, | |
454 | struct autofs_dev_ioctl *param) | |
455 | { | |
456 | unsigned long timeout; | |
457 | ||
458 | timeout = param->arg1; | |
459 | param->arg1 = sbi->exp_timeout / HZ; | |
460 | sbi->exp_timeout = timeout * HZ; | |
461 | return 0; | |
462 | } | |
463 | ||
464 | /* | |
465 | * Return the uid and gid of the last request for the mount | |
466 | * | |
467 | * When reconstructing an autofs mount tree with active mounts | |
468 | * we need to re-connect to mounts that may have used the original | |
469 | * process uid and gid (or string variations of them) for mount | |
470 | * lookups within the map entry. | |
471 | */ | |
472 | static int autofs_dev_ioctl_requester(struct file *fp, | |
473 | struct autofs_sb_info *sbi, | |
474 | struct autofs_dev_ioctl *param) | |
475 | { | |
476 | struct autofs_info *ino; | |
477 | struct nameidata nd; | |
478 | const char *path; | |
479 | dev_t devid; | |
480 | int err = -ENOENT; | |
481 | ||
482 | if (param->size <= sizeof(*param)) { | |
483 | err = -EINVAL; | |
484 | goto out; | |
485 | } | |
486 | ||
487 | path = param->path; | |
488 | devid = sbi->sb->s_dev; | |
489 | ||
490 | param->arg1 = param->arg2 = -1; | |
491 | ||
492 | /* Get nameidata of the parent directory */ | |
493 | err = path_lookup(path, LOOKUP_PARENT, &nd); | |
494 | if (err) | |
495 | goto out; | |
496 | ||
497 | err = autofs_dev_ioctl_find_super(&nd, devid); | |
498 | if (err) | |
499 | goto out_release; | |
500 | ||
501 | ino = autofs4_dentry_ino(nd.path.dentry); | |
502 | if (ino) { | |
503 | err = 0; | |
504 | autofs4_expire_wait(nd.path.dentry); | |
505 | spin_lock(&sbi->fs_lock); | |
506 | param->arg1 = ino->uid; | |
507 | param->arg2 = ino->gid; | |
508 | spin_unlock(&sbi->fs_lock); | |
509 | } | |
510 | ||
511 | out_release: | |
512 | path_put(&nd.path); | |
513 | out: | |
514 | return err; | |
515 | } | |
516 | ||
517 | /* | |
518 | * Call repeatedly until it returns -EAGAIN, meaning there's nothing | |
519 | * more that can be done. | |
520 | */ | |
521 | static int autofs_dev_ioctl_expire(struct file *fp, | |
522 | struct autofs_sb_info *sbi, | |
523 | struct autofs_dev_ioctl *param) | |
524 | { | |
525 | struct dentry *dentry; | |
526 | struct vfsmount *mnt; | |
527 | int err = -EAGAIN; | |
528 | int how; | |
529 | ||
530 | how = param->arg1; | |
531 | mnt = fp->f_path.mnt; | |
532 | ||
533 | if (sbi->type & AUTOFS_TYPE_TRIGGER) | |
534 | dentry = autofs4_expire_direct(sbi->sb, mnt, sbi, how); | |
535 | else | |
536 | dentry = autofs4_expire_indirect(sbi->sb, mnt, sbi, how); | |
537 | ||
538 | if (dentry) { | |
539 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
540 | ||
541 | /* | |
542 | * This is synchronous because it makes the daemon a | |
543 | * little easier | |
544 | */ | |
545 | err = autofs4_wait(sbi, dentry, NFY_EXPIRE); | |
546 | ||
547 | spin_lock(&sbi->fs_lock); | |
548 | if (ino->flags & AUTOFS_INF_MOUNTPOINT) { | |
549 | ino->flags &= ~AUTOFS_INF_MOUNTPOINT; | |
550 | sbi->sb->s_root->d_mounted++; | |
551 | } | |
552 | ino->flags &= ~AUTOFS_INF_EXPIRING; | |
553 | complete_all(&ino->expire_complete); | |
554 | spin_unlock(&sbi->fs_lock); | |
555 | dput(dentry); | |
556 | } | |
557 | ||
558 | return err; | |
559 | } | |
560 | ||
561 | /* Check if autofs mount point is in use */ | |
562 | static int autofs_dev_ioctl_askumount(struct file *fp, | |
563 | struct autofs_sb_info *sbi, | |
564 | struct autofs_dev_ioctl *param) | |
565 | { | |
566 | param->arg1 = 0; | |
567 | if (may_umount(fp->f_path.mnt)) | |
568 | param->arg1 = 1; | |
569 | return 0; | |
570 | } | |
571 | ||
572 | /* | |
573 | * Check if the given path is a mountpoint. | |
574 | * | |
575 | * If we are supplied with the file descriptor of an autofs | |
576 | * mount we're looking for a specific mount. In this case | |
577 | * the path is considered a mountpoint if it is itself a | |
578 | * mountpoint or contains a mount, such as a multi-mount | |
579 | * without a root mount. In this case we return 1 if the | |
580 | * path is a mount point and the super magic of the covering | |
581 | * mount if there is one or 0 if it isn't a mountpoint. | |
582 | * | |
583 | * If we aren't supplied with a file descriptor then we | |
584 | * lookup the nameidata of the path and check if it is the | |
585 | * root of a mount. If a type is given we are looking for | |
586 | * a particular autofs mount and if we don't find a match | |
587 | * we return fail. If the located nameidata path is the | |
588 | * root of a mount we return 1 along with the super magic | |
589 | * of the mount or 0 otherwise. | |
590 | * | |
591 | * In both cases the the device number (as returned by | |
592 | * new_encode_dev()) is also returned. | |
593 | */ | |
594 | static int autofs_dev_ioctl_ismountpoint(struct file *fp, | |
595 | struct autofs_sb_info *sbi, | |
596 | struct autofs_dev_ioctl *param) | |
597 | { | |
598 | struct nameidata nd; | |
599 | const char *path; | |
600 | unsigned int type; | |
601 | int err = -ENOENT; | |
602 | ||
603 | if (param->size <= sizeof(*param)) { | |
604 | err = -EINVAL; | |
605 | goto out; | |
606 | } | |
607 | ||
608 | path = param->path; | |
609 | type = param->arg1; | |
610 | ||
611 | param->arg1 = 0; | |
612 | param->arg2 = 0; | |
613 | ||
614 | if (!fp || param->ioctlfd == -1) { | |
615 | if (type == AUTOFS_TYPE_ANY) { | |
616 | struct super_block *sb; | |
617 | ||
618 | err = path_lookup(path, LOOKUP_FOLLOW, &nd); | |
619 | if (err) | |
620 | goto out; | |
621 | ||
622 | sb = nd.path.dentry->d_sb; | |
623 | param->arg1 = new_encode_dev(sb->s_dev); | |
624 | } else { | |
625 | struct autofs_info *ino; | |
626 | ||
627 | err = path_lookup(path, LOOKUP_PARENT, &nd); | |
628 | if (err) | |
629 | goto out; | |
630 | ||
631 | err = autofs_dev_ioctl_find_sbi_type(&nd, type); | |
632 | if (err) | |
633 | goto out_release; | |
634 | ||
635 | ino = autofs4_dentry_ino(nd.path.dentry); | |
636 | param->arg1 = autofs4_get_dev(ino->sbi); | |
637 | } | |
638 | ||
639 | err = 0; | |
640 | if (nd.path.dentry->d_inode && | |
641 | nd.path.mnt->mnt_root == nd.path.dentry) { | |
642 | err = 1; | |
643 | param->arg2 = nd.path.dentry->d_inode->i_sb->s_magic; | |
644 | } | |
645 | } else { | |
646 | dev_t devid = new_encode_dev(sbi->sb->s_dev); | |
647 | ||
648 | err = path_lookup(path, LOOKUP_PARENT, &nd); | |
649 | if (err) | |
650 | goto out; | |
651 | ||
652 | err = autofs_dev_ioctl_find_super(&nd, devid); | |
653 | if (err) | |
654 | goto out_release; | |
655 | ||
656 | param->arg1 = autofs4_get_dev(sbi); | |
657 | ||
658 | err = have_submounts(nd.path.dentry); | |
659 | ||
660 | if (nd.path.mnt->mnt_mountpoint != nd.path.mnt->mnt_root) { | |
661 | if (follow_down(&nd.path.mnt, &nd.path.dentry)) { | |
662 | struct inode *inode = nd.path.dentry->d_inode; | |
663 | param->arg2 = inode->i_sb->s_magic; | |
664 | } | |
665 | } | |
666 | } | |
667 | ||
668 | out_release: | |
669 | path_put(&nd.path); | |
670 | out: | |
671 | return err; | |
672 | } | |
673 | ||
674 | /* | |
675 | * Our range of ioctl numbers isn't 0 based so we need to shift | |
676 | * the array index by _IOC_NR(AUTOFS_CTL_IOC_FIRST) for the table | |
677 | * lookup. | |
678 | */ | |
679 | #define cmd_idx(cmd) (cmd - _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST)) | |
680 | ||
681 | static ioctl_fn lookup_dev_ioctl(unsigned int cmd) | |
682 | { | |
683 | static struct { | |
684 | int cmd; | |
685 | ioctl_fn fn; | |
686 | } _ioctls[] = { | |
687 | {cmd_idx(AUTOFS_DEV_IOCTL_VERSION_CMD), NULL}, | |
688 | {cmd_idx(AUTOFS_DEV_IOCTL_PROTOVER_CMD), | |
689 | autofs_dev_ioctl_protover}, | |
690 | {cmd_idx(AUTOFS_DEV_IOCTL_PROTOSUBVER_CMD), | |
691 | autofs_dev_ioctl_protosubver}, | |
692 | {cmd_idx(AUTOFS_DEV_IOCTL_OPENMOUNT_CMD), | |
693 | autofs_dev_ioctl_openmount}, | |
694 | {cmd_idx(AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD), | |
695 | autofs_dev_ioctl_closemount}, | |
696 | {cmd_idx(AUTOFS_DEV_IOCTL_READY_CMD), | |
697 | autofs_dev_ioctl_ready}, | |
698 | {cmd_idx(AUTOFS_DEV_IOCTL_FAIL_CMD), | |
699 | autofs_dev_ioctl_fail}, | |
700 | {cmd_idx(AUTOFS_DEV_IOCTL_SETPIPEFD_CMD), | |
701 | autofs_dev_ioctl_setpipefd}, | |
702 | {cmd_idx(AUTOFS_DEV_IOCTL_CATATONIC_CMD), | |
703 | autofs_dev_ioctl_catatonic}, | |
704 | {cmd_idx(AUTOFS_DEV_IOCTL_TIMEOUT_CMD), | |
705 | autofs_dev_ioctl_timeout}, | |
706 | {cmd_idx(AUTOFS_DEV_IOCTL_REQUESTER_CMD), | |
707 | autofs_dev_ioctl_requester}, | |
708 | {cmd_idx(AUTOFS_DEV_IOCTL_EXPIRE_CMD), | |
709 | autofs_dev_ioctl_expire}, | |
710 | {cmd_idx(AUTOFS_DEV_IOCTL_ASKUMOUNT_CMD), | |
711 | autofs_dev_ioctl_askumount}, | |
712 | {cmd_idx(AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD), | |
713 | autofs_dev_ioctl_ismountpoint} | |
714 | }; | |
715 | unsigned int idx = cmd_idx(cmd); | |
716 | ||
717 | return (idx >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[idx].fn; | |
718 | } | |
719 | ||
720 | /* ioctl dispatcher */ | |
721 | static int _autofs_dev_ioctl(unsigned int command, struct autofs_dev_ioctl __user *user) | |
722 | { | |
723 | struct autofs_dev_ioctl *param; | |
724 | struct file *fp; | |
725 | struct autofs_sb_info *sbi; | |
726 | unsigned int cmd_first, cmd; | |
727 | ioctl_fn fn = NULL; | |
728 | int err = 0; | |
729 | ||
730 | /* only root can play with this */ | |
731 | if (!capable(CAP_SYS_ADMIN)) | |
732 | return -EPERM; | |
733 | ||
734 | cmd_first = _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST); | |
735 | cmd = _IOC_NR(command); | |
736 | ||
737 | if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) || | |
738 | cmd - cmd_first >= AUTOFS_DEV_IOCTL_IOC_COUNT) { | |
739 | return -ENOTTY; | |
740 | } | |
741 | ||
742 | /* Copy the parameters into kernel space. */ | |
743 | param = copy_dev_ioctl(user); | |
744 | if (IS_ERR(param)) | |
745 | return PTR_ERR(param); | |
746 | ||
747 | err = validate_dev_ioctl(command, param); | |
748 | if (err) | |
749 | goto out; | |
750 | ||
751 | /* The validate routine above always sets the version */ | |
752 | if (cmd == AUTOFS_DEV_IOCTL_VERSION_CMD) | |
753 | goto done; | |
754 | ||
755 | fn = lookup_dev_ioctl(cmd); | |
756 | if (!fn) { | |
757 | AUTOFS_WARN("unknown command 0x%08x", command); | |
758 | return -ENOTTY; | |
759 | } | |
760 | ||
761 | fp = NULL; | |
762 | sbi = NULL; | |
763 | ||
764 | /* | |
765 | * For obvious reasons the openmount can't have a file | |
766 | * descriptor yet. We don't take a reference to the | |
767 | * file during close to allow for immediate release. | |
768 | */ | |
769 | if (cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD && | |
770 | cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) { | |
771 | fp = fget(param->ioctlfd); | |
772 | if (!fp) { | |
773 | if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) | |
774 | goto cont; | |
775 | err = -EBADF; | |
776 | goto out; | |
777 | } | |
778 | ||
779 | if (!fp->f_op) { | |
780 | err = -ENOTTY; | |
781 | fput(fp); | |
782 | goto out; | |
783 | } | |
784 | ||
785 | sbi = autofs_dev_ioctl_sbi(fp); | |
786 | if (!sbi || sbi->magic != AUTOFS_SBI_MAGIC) { | |
787 | err = -EINVAL; | |
788 | fput(fp); | |
789 | goto out; | |
790 | } | |
791 | ||
792 | /* | |
793 | * Admin needs to be able to set the mount catatonic in | |
794 | * order to be able to perform the re-open. | |
795 | */ | |
796 | if (!autofs4_oz_mode(sbi) && | |
797 | cmd != AUTOFS_DEV_IOCTL_CATATONIC_CMD) { | |
798 | err = -EACCES; | |
799 | fput(fp); | |
800 | goto out; | |
801 | } | |
802 | } | |
803 | cont: | |
804 | err = fn(fp, sbi, param); | |
805 | ||
806 | if (fp) | |
807 | fput(fp); | |
808 | done: | |
809 | if (err >= 0 && copy_to_user(user, param, AUTOFS_DEV_IOCTL_SIZE)) | |
810 | err = -EFAULT; | |
811 | out: | |
812 | free_dev_ioctl(param); | |
813 | return err; | |
814 | } | |
815 | ||
816 | static long autofs_dev_ioctl(struct file *file, uint command, ulong u) | |
817 | { | |
818 | int err; | |
819 | err = _autofs_dev_ioctl(command, (struct autofs_dev_ioctl __user *) u); | |
820 | return (long) err; | |
821 | } | |
822 | ||
823 | #ifdef CONFIG_COMPAT | |
824 | static long autofs_dev_ioctl_compat(struct file *file, uint command, ulong u) | |
825 | { | |
826 | return (long) autofs_dev_ioctl(file, command, (ulong) compat_ptr(u)); | |
827 | } | |
828 | #else | |
829 | #define autofs_dev_ioctl_compat NULL | |
830 | #endif | |
831 | ||
832 | static const struct file_operations _dev_ioctl_fops = { | |
833 | .unlocked_ioctl = autofs_dev_ioctl, | |
834 | .compat_ioctl = autofs_dev_ioctl_compat, | |
835 | .owner = THIS_MODULE, | |
836 | }; | |
837 | ||
838 | static struct miscdevice _autofs_dev_ioctl_misc = { | |
839 | .minor = MISC_DYNAMIC_MINOR, | |
840 | .name = AUTOFS_DEVICE_NAME, | |
841 | .fops = &_dev_ioctl_fops | |
842 | }; | |
843 | ||
844 | /* Register/deregister misc character device */ | |
845 | int autofs_dev_ioctl_init(void) | |
846 | { | |
847 | int r; | |
848 | ||
849 | r = misc_register(&_autofs_dev_ioctl_misc); | |
850 | if (r) { | |
851 | AUTOFS_ERROR("misc_register failed for control device"); | |
852 | return r; | |
853 | } | |
854 | ||
855 | return 0; | |
856 | } | |
857 | ||
858 | void autofs_dev_ioctl_exit(void) | |
859 | { | |
860 | misc_deregister(&_autofs_dev_ioctl_misc); | |
861 | return; | |
862 | } | |
863 |