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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 | { | |
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)) { | |
141 | err = check_name(param->path); | |
142 | if (err) { | |
143 | AUTOFS_WARN("invalid path supplied for cmd(0x%08x)", | |
144 | cmd); | |
145 | goto out; | |
146 | } | |
147 | ||
148 | err = invalid_str(param->path, | |
149 | (void *) ((size_t) param + param->size)); | |
150 | if (err) { | |
151 | AUTOFS_WARN("invalid path supplied for cmd(0x%08x)", | |
152 | cmd); | |
153 | goto out; | |
154 | } | |
155 | } | |
156 | ||
157 | err = 0; | |
158 | out: | |
159 | return err; | |
160 | } | |
161 | ||
162 | /* | |
163 | * Get the autofs super block info struct from the file opened on | |
164 | * the autofs mount point. | |
165 | */ | |
166 | static struct autofs_sb_info *autofs_dev_ioctl_sbi(struct file *f) | |
167 | { | |
168 | struct autofs_sb_info *sbi = NULL; | |
169 | struct inode *inode; | |
170 | ||
171 | if (f) { | |
172 | inode = f->f_path.dentry->d_inode; | |
173 | sbi = autofs4_sbi(inode->i_sb); | |
174 | } | |
175 | return sbi; | |
176 | } | |
177 | ||
178 | /* Return autofs module protocol version */ | |
179 | static int autofs_dev_ioctl_protover(struct file *fp, | |
180 | struct autofs_sb_info *sbi, | |
181 | struct autofs_dev_ioctl *param) | |
182 | { | |
183 | param->arg1 = sbi->version; | |
184 | return 0; | |
185 | } | |
186 | ||
187 | /* Return autofs module protocol sub version */ | |
188 | static int autofs_dev_ioctl_protosubver(struct file *fp, | |
189 | struct autofs_sb_info *sbi, | |
190 | struct autofs_dev_ioctl *param) | |
191 | { | |
192 | param->arg1 = sbi->sub_version; | |
193 | return 0; | |
194 | } | |
195 | ||
196 | /* | |
197 | * Walk down the mount stack looking for an autofs mount that | |
198 | * has the requested device number (aka. new_encode_dev(sb->s_dev). | |
199 | */ | |
200 | static int autofs_dev_ioctl_find_super(struct nameidata *nd, dev_t devno) | |
201 | { | |
202 | struct dentry *dentry; | |
203 | struct inode *inode; | |
204 | struct super_block *sb; | |
205 | dev_t s_dev; | |
206 | unsigned int err; | |
207 | ||
208 | err = -ENOENT; | |
209 | ||
210 | /* Lookup the dentry name at the base of our mount point */ | |
211 | dentry = d_lookup(nd->path.dentry, &nd->last); | |
212 | if (!dentry) | |
213 | goto out; | |
214 | ||
215 | dput(nd->path.dentry); | |
216 | nd->path.dentry = dentry; | |
217 | ||
218 | /* And follow the mount stack looking for our autofs mount */ | |
219 | while (follow_down(&nd->path.mnt, &nd->path.dentry)) { | |
220 | inode = nd->path.dentry->d_inode; | |
221 | if (!inode) | |
222 | break; | |
223 | ||
224 | sb = inode->i_sb; | |
225 | s_dev = new_encode_dev(sb->s_dev); | |
226 | if (devno == s_dev) { | |
227 | if (sb->s_magic == AUTOFS_SUPER_MAGIC) { | |
228 | err = 0; | |
229 | break; | |
230 | } | |
231 | } | |
232 | } | |
233 | out: | |
234 | return err; | |
235 | } | |
236 | ||
237 | /* | |
238 | * Walk down the mount stack looking for an autofs mount that | |
239 | * has the requested mount type (ie. indirect, direct or offset). | |
240 | */ | |
241 | static int autofs_dev_ioctl_find_sbi_type(struct nameidata *nd, unsigned int type) | |
242 | { | |
243 | struct dentry *dentry; | |
244 | struct autofs_info *ino; | |
245 | unsigned int err; | |
246 | ||
247 | err = -ENOENT; | |
248 | ||
249 | /* Lookup the dentry name at the base of our mount point */ | |
250 | dentry = d_lookup(nd->path.dentry, &nd->last); | |
251 | if (!dentry) | |
252 | goto out; | |
253 | ||
254 | dput(nd->path.dentry); | |
255 | nd->path.dentry = dentry; | |
256 | ||
257 | /* And follow the mount stack looking for our autofs mount */ | |
258 | while (follow_down(&nd->path.mnt, &nd->path.dentry)) { | |
259 | ino = autofs4_dentry_ino(nd->path.dentry); | |
260 | if (ino && ino->sbi->type & type) { | |
261 | err = 0; | |
262 | break; | |
263 | } | |
264 | } | |
265 | out: | |
266 | return err; | |
267 | } | |
268 | ||
269 | static void autofs_dev_ioctl_fd_install(unsigned int fd, struct file *file) | |
270 | { | |
271 | struct files_struct *files = current->files; | |
272 | struct fdtable *fdt; | |
273 | ||
274 | spin_lock(&files->file_lock); | |
275 | fdt = files_fdtable(files); | |
276 | BUG_ON(fdt->fd[fd] != NULL); | |
277 | rcu_assign_pointer(fdt->fd[fd], file); | |
278 | FD_SET(fd, fdt->close_on_exec); | |
279 | spin_unlock(&files->file_lock); | |
280 | } | |
281 | ||
282 | ||
283 | /* | |
284 | * Open a file descriptor on the autofs mount point corresponding | |
285 | * to the given path and device number (aka. new_encode_dev(sb->s_dev)). | |
286 | */ | |
287 | static int autofs_dev_ioctl_open_mountpoint(const char *path, dev_t devid) | |
288 | { | |
289 | struct file *filp; | |
290 | struct nameidata nd; | |
291 | int err, fd; | |
292 | ||
293 | fd = get_unused_fd(); | |
294 | if (likely(fd >= 0)) { | |
295 | /* Get nameidata of the parent directory */ | |
296 | err = path_lookup(path, LOOKUP_PARENT, &nd); | |
297 | if (err) | |
298 | goto out; | |
299 | ||
300 | /* | |
301 | * Search down, within the parent, looking for an | |
302 | * autofs super block that has the device number | |
303 | * corresponding to the autofs fs we want to open. | |
304 | */ | |
305 | err = autofs_dev_ioctl_find_super(&nd, devid); | |
306 | if (err) { | |
307 | path_put(&nd.path); | |
308 | goto out; | |
309 | } | |
310 | ||
311 | filp = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY); | |
312 | if (IS_ERR(filp)) { | |
313 | err = PTR_ERR(filp); | |
314 | goto out; | |
315 | } | |
316 | ||
317 | autofs_dev_ioctl_fd_install(fd, filp); | |
318 | } | |
319 | ||
320 | return fd; | |
321 | ||
322 | out: | |
323 | put_unused_fd(fd); | |
324 | return err; | |
325 | } | |
326 | ||
327 | /* Open a file descriptor on an autofs mount point */ | |
328 | static int autofs_dev_ioctl_openmount(struct file *fp, | |
329 | struct autofs_sb_info *sbi, | |
330 | struct autofs_dev_ioctl *param) | |
331 | { | |
332 | const char *path; | |
333 | dev_t devid; | |
334 | int err, fd; | |
335 | ||
336 | /* param->path has already been checked */ | |
337 | if (!param->arg1) | |
338 | return -EINVAL; | |
339 | ||
340 | param->ioctlfd = -1; | |
341 | ||
342 | path = param->path; | |
343 | devid = param->arg1; | |
344 | ||
345 | err = 0; | |
346 | fd = autofs_dev_ioctl_open_mountpoint(path, devid); | |
347 | if (unlikely(fd < 0)) { | |
348 | err = fd; | |
349 | goto out; | |
350 | } | |
351 | ||
352 | param->ioctlfd = fd; | |
353 | out: | |
354 | return err; | |
355 | } | |
356 | ||
357 | /* Close file descriptor allocated above (user can also use close(2)). */ | |
358 | static int autofs_dev_ioctl_closemount(struct file *fp, | |
359 | struct autofs_sb_info *sbi, | |
360 | struct autofs_dev_ioctl *param) | |
361 | { | |
362 | return sys_close(param->ioctlfd); | |
363 | } | |
364 | ||
365 | /* | |
366 | * Send "ready" status for an existing wait (either a mount or an expire | |
367 | * request). | |
368 | */ | |
369 | static int autofs_dev_ioctl_ready(struct file *fp, | |
370 | struct autofs_sb_info *sbi, | |
371 | struct autofs_dev_ioctl *param) | |
372 | { | |
373 | autofs_wqt_t token; | |
374 | ||
375 | token = (autofs_wqt_t) param->arg1; | |
376 | return autofs4_wait_release(sbi, token, 0); | |
377 | } | |
378 | ||
379 | /* | |
380 | * Send "fail" status for an existing wait (either a mount or an expire | |
381 | * request). | |
382 | */ | |
383 | static int autofs_dev_ioctl_fail(struct file *fp, | |
384 | struct autofs_sb_info *sbi, | |
385 | struct autofs_dev_ioctl *param) | |
386 | { | |
387 | autofs_wqt_t token; | |
388 | int status; | |
389 | ||
390 | token = (autofs_wqt_t) param->arg1; | |
391 | status = param->arg2 ? param->arg2 : -ENOENT; | |
392 | return autofs4_wait_release(sbi, token, status); | |
393 | } | |
394 | ||
395 | /* | |
396 | * Set the pipe fd for kernel communication to the daemon. | |
397 | * | |
398 | * Normally this is set at mount using an option but if we | |
399 | * are reconnecting to a busy mount then we need to use this | |
400 | * to tell the autofs mount about the new kernel pipe fd. In | |
401 | * order to protect mounts against incorrectly setting the | |
402 | * pipefd we also require that the autofs mount be catatonic. | |
403 | * | |
404 | * This also sets the process group id used to identify the | |
405 | * controlling process (eg. the owning automount(8) daemon). | |
406 | */ | |
407 | static int autofs_dev_ioctl_setpipefd(struct file *fp, | |
408 | struct autofs_sb_info *sbi, | |
409 | struct autofs_dev_ioctl *param) | |
410 | { | |
411 | int pipefd; | |
412 | int err = 0; | |
413 | ||
414 | if (param->arg1 == -1) | |
415 | return -EINVAL; | |
416 | ||
417 | pipefd = param->arg1; | |
418 | ||
419 | mutex_lock(&sbi->wq_mutex); | |
420 | if (!sbi->catatonic) { | |
421 | mutex_unlock(&sbi->wq_mutex); | |
422 | return -EBUSY; | |
423 | } else { | |
424 | struct file *pipe = fget(pipefd); | |
425 | if (!pipe->f_op || !pipe->f_op->write) { | |
426 | err = -EPIPE; | |
427 | fput(pipe); | |
428 | goto out; | |
429 | } | |
430 | sbi->oz_pgrp = task_pgrp_nr(current); | |
431 | sbi->pipefd = pipefd; | |
432 | sbi->pipe = pipe; | |
433 | sbi->catatonic = 0; | |
434 | } | |
435 | out: | |
436 | mutex_unlock(&sbi->wq_mutex); | |
437 | return err; | |
438 | } | |
439 | ||
440 | /* | |
441 | * Make the autofs mount point catatonic, no longer responsive to | |
442 | * mount requests. Also closes the kernel pipe file descriptor. | |
443 | */ | |
444 | static int autofs_dev_ioctl_catatonic(struct file *fp, | |
445 | struct autofs_sb_info *sbi, | |
446 | struct autofs_dev_ioctl *param) | |
447 | { | |
448 | autofs4_catatonic_mode(sbi); | |
449 | return 0; | |
450 | } | |
451 | ||
452 | /* Set the autofs mount timeout */ | |
453 | static int autofs_dev_ioctl_timeout(struct file *fp, | |
454 | struct autofs_sb_info *sbi, | |
455 | struct autofs_dev_ioctl *param) | |
456 | { | |
457 | unsigned long timeout; | |
458 | ||
459 | timeout = param->arg1; | |
460 | param->arg1 = sbi->exp_timeout / HZ; | |
461 | sbi->exp_timeout = timeout * HZ; | |
462 | return 0; | |
463 | } | |
464 | ||
465 | /* | |
466 | * Return the uid and gid of the last request for the mount | |
467 | * | |
468 | * When reconstructing an autofs mount tree with active mounts | |
469 | * we need to re-connect to mounts that may have used the original | |
470 | * process uid and gid (or string variations of them) for mount | |
471 | * lookups within the map entry. | |
472 | */ | |
473 | static int autofs_dev_ioctl_requester(struct file *fp, | |
474 | struct autofs_sb_info *sbi, | |
475 | struct autofs_dev_ioctl *param) | |
476 | { | |
477 | struct autofs_info *ino; | |
478 | struct nameidata nd; | |
479 | const char *path; | |
480 | dev_t devid; | |
481 | int err = -ENOENT; | |
482 | ||
483 | if (param->size <= sizeof(*param)) { | |
484 | err = -EINVAL; | |
485 | goto out; | |
486 | } | |
487 | ||
488 | path = param->path; | |
489 | devid = sbi->sb->s_dev; | |
490 | ||
491 | param->arg1 = param->arg2 = -1; | |
492 | ||
493 | /* Get nameidata of the parent directory */ | |
494 | err = path_lookup(path, LOOKUP_PARENT, &nd); | |
495 | if (err) | |
496 | goto out; | |
497 | ||
498 | err = autofs_dev_ioctl_find_super(&nd, devid); | |
499 | if (err) | |
500 | goto out_release; | |
501 | ||
502 | ino = autofs4_dentry_ino(nd.path.dentry); | |
503 | if (ino) { | |
504 | err = 0; | |
505 | autofs4_expire_wait(nd.path.dentry); | |
506 | spin_lock(&sbi->fs_lock); | |
507 | param->arg1 = ino->uid; | |
508 | param->arg2 = ino->gid; | |
509 | spin_unlock(&sbi->fs_lock); | |
510 | } | |
511 | ||
512 | out_release: | |
513 | path_put(&nd.path); | |
514 | out: | |
515 | return err; | |
516 | } | |
517 | ||
518 | /* | |
519 | * Call repeatedly until it returns -EAGAIN, meaning there's nothing | |
520 | * more that can be done. | |
521 | */ | |
522 | static int autofs_dev_ioctl_expire(struct file *fp, | |
523 | struct autofs_sb_info *sbi, | |
524 | struct autofs_dev_ioctl *param) | |
525 | { | |
526 | struct dentry *dentry; | |
527 | struct vfsmount *mnt; | |
528 | int err = -EAGAIN; | |
529 | int how; | |
530 | ||
531 | how = param->arg1; | |
532 | mnt = fp->f_path.mnt; | |
533 | ||
534 | if (sbi->type & AUTOFS_TYPE_TRIGGER) | |
535 | dentry = autofs4_expire_direct(sbi->sb, mnt, sbi, how); | |
536 | else | |
537 | dentry = autofs4_expire_indirect(sbi->sb, mnt, sbi, how); | |
538 | ||
539 | if (dentry) { | |
540 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
541 | ||
542 | /* | |
543 | * This is synchronous because it makes the daemon a | |
544 | * little easier | |
545 | */ | |
546 | err = autofs4_wait(sbi, dentry, NFY_EXPIRE); | |
547 | ||
548 | spin_lock(&sbi->fs_lock); | |
549 | if (ino->flags & AUTOFS_INF_MOUNTPOINT) { | |
550 | ino->flags &= ~AUTOFS_INF_MOUNTPOINT; | |
551 | sbi->sb->s_root->d_mounted++; | |
552 | } | |
553 | ino->flags &= ~AUTOFS_INF_EXPIRING; | |
554 | complete_all(&ino->expire_complete); | |
555 | spin_unlock(&sbi->fs_lock); | |
556 | dput(dentry); | |
557 | } | |
558 | ||
559 | return err; | |
560 | } | |
561 | ||
562 | /* Check if autofs mount point is in use */ | |
563 | static int autofs_dev_ioctl_askumount(struct file *fp, | |
564 | struct autofs_sb_info *sbi, | |
565 | struct autofs_dev_ioctl *param) | |
566 | { | |
567 | param->arg1 = 0; | |
568 | if (may_umount(fp->f_path.mnt)) | |
569 | param->arg1 = 1; | |
570 | return 0; | |
571 | } | |
572 | ||
573 | /* | |
574 | * Check if the given path is a mountpoint. | |
575 | * | |
576 | * If we are supplied with the file descriptor of an autofs | |
577 | * mount we're looking for a specific mount. In this case | |
578 | * the path is considered a mountpoint if it is itself a | |
579 | * mountpoint or contains a mount, such as a multi-mount | |
580 | * without a root mount. In this case we return 1 if the | |
581 | * path is a mount point and the super magic of the covering | |
582 | * mount if there is one or 0 if it isn't a mountpoint. | |
583 | * | |
584 | * If we aren't supplied with a file descriptor then we | |
585 | * lookup the nameidata of the path and check if it is the | |
586 | * root of a mount. If a type is given we are looking for | |
587 | * a particular autofs mount and if we don't find a match | |
588 | * we return fail. If the located nameidata path is the | |
589 | * root of a mount we return 1 along with the super magic | |
590 | * of the mount or 0 otherwise. | |
591 | * | |
592 | * In both cases the the device number (as returned by | |
593 | * new_encode_dev()) is also returned. | |
594 | */ | |
595 | static int autofs_dev_ioctl_ismountpoint(struct file *fp, | |
596 | struct autofs_sb_info *sbi, | |
597 | struct autofs_dev_ioctl *param) | |
598 | { | |
599 | struct nameidata nd; | |
600 | const char *path; | |
601 | unsigned int type; | |
602 | int err = -ENOENT; | |
603 | ||
604 | if (param->size <= sizeof(*param)) { | |
605 | err = -EINVAL; | |
606 | goto out; | |
607 | } | |
608 | ||
609 | path = param->path; | |
610 | type = param->arg1; | |
611 | ||
612 | param->arg1 = 0; | |
613 | param->arg2 = 0; | |
614 | ||
615 | if (!fp || param->ioctlfd == -1) { | |
616 | if (type == AUTOFS_TYPE_ANY) { | |
617 | struct super_block *sb; | |
618 | ||
619 | err = path_lookup(path, LOOKUP_FOLLOW, &nd); | |
620 | if (err) | |
621 | goto out; | |
622 | ||
623 | sb = nd.path.dentry->d_sb; | |
624 | param->arg1 = new_encode_dev(sb->s_dev); | |
625 | } else { | |
626 | struct autofs_info *ino; | |
627 | ||
628 | err = path_lookup(path, LOOKUP_PARENT, &nd); | |
629 | if (err) | |
630 | goto out; | |
631 | ||
632 | err = autofs_dev_ioctl_find_sbi_type(&nd, type); | |
633 | if (err) | |
634 | goto out_release; | |
635 | ||
636 | ino = autofs4_dentry_ino(nd.path.dentry); | |
637 | param->arg1 = autofs4_get_dev(ino->sbi); | |
638 | } | |
639 | ||
640 | err = 0; | |
641 | if (nd.path.dentry->d_inode && | |
642 | nd.path.mnt->mnt_root == nd.path.dentry) { | |
643 | err = 1; | |
644 | param->arg2 = nd.path.dentry->d_inode->i_sb->s_magic; | |
645 | } | |
646 | } else { | |
647 | dev_t devid = new_encode_dev(sbi->sb->s_dev); | |
648 | ||
649 | err = path_lookup(path, LOOKUP_PARENT, &nd); | |
650 | if (err) | |
651 | goto out; | |
652 | ||
653 | err = autofs_dev_ioctl_find_super(&nd, devid); | |
654 | if (err) | |
655 | goto out_release; | |
656 | ||
657 | param->arg1 = autofs4_get_dev(sbi); | |
658 | ||
659 | err = have_submounts(nd.path.dentry); | |
660 | ||
661 | if (nd.path.mnt->mnt_mountpoint != nd.path.mnt->mnt_root) { | |
662 | if (follow_down(&nd.path.mnt, &nd.path.dentry)) { | |
663 | struct inode *inode = nd.path.dentry->d_inode; | |
664 | param->arg2 = inode->i_sb->s_magic; | |
665 | } | |
666 | } | |
667 | } | |
668 | ||
669 | out_release: | |
670 | path_put(&nd.path); | |
671 | out: | |
672 | return err; | |
673 | } | |
674 | ||
675 | /* | |
676 | * Our range of ioctl numbers isn't 0 based so we need to shift | |
677 | * the array index by _IOC_NR(AUTOFS_CTL_IOC_FIRST) for the table | |
678 | * lookup. | |
679 | */ | |
680 | #define cmd_idx(cmd) (cmd - _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST)) | |
681 | ||
682 | static ioctl_fn lookup_dev_ioctl(unsigned int cmd) | |
683 | { | |
684 | static struct { | |
685 | int cmd; | |
686 | ioctl_fn fn; | |
687 | } _ioctls[] = { | |
688 | {cmd_idx(AUTOFS_DEV_IOCTL_VERSION_CMD), NULL}, | |
689 | {cmd_idx(AUTOFS_DEV_IOCTL_PROTOVER_CMD), | |
690 | autofs_dev_ioctl_protover}, | |
691 | {cmd_idx(AUTOFS_DEV_IOCTL_PROTOSUBVER_CMD), | |
692 | autofs_dev_ioctl_protosubver}, | |
693 | {cmd_idx(AUTOFS_DEV_IOCTL_OPENMOUNT_CMD), | |
694 | autofs_dev_ioctl_openmount}, | |
695 | {cmd_idx(AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD), | |
696 | autofs_dev_ioctl_closemount}, | |
697 | {cmd_idx(AUTOFS_DEV_IOCTL_READY_CMD), | |
698 | autofs_dev_ioctl_ready}, | |
699 | {cmd_idx(AUTOFS_DEV_IOCTL_FAIL_CMD), | |
700 | autofs_dev_ioctl_fail}, | |
701 | {cmd_idx(AUTOFS_DEV_IOCTL_SETPIPEFD_CMD), | |
702 | autofs_dev_ioctl_setpipefd}, | |
703 | {cmd_idx(AUTOFS_DEV_IOCTL_CATATONIC_CMD), | |
704 | autofs_dev_ioctl_catatonic}, | |
705 | {cmd_idx(AUTOFS_DEV_IOCTL_TIMEOUT_CMD), | |
706 | autofs_dev_ioctl_timeout}, | |
707 | {cmd_idx(AUTOFS_DEV_IOCTL_REQUESTER_CMD), | |
708 | autofs_dev_ioctl_requester}, | |
709 | {cmd_idx(AUTOFS_DEV_IOCTL_EXPIRE_CMD), | |
710 | autofs_dev_ioctl_expire}, | |
711 | {cmd_idx(AUTOFS_DEV_IOCTL_ASKUMOUNT_CMD), | |
712 | autofs_dev_ioctl_askumount}, | |
713 | {cmd_idx(AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD), | |
714 | autofs_dev_ioctl_ismountpoint} | |
715 | }; | |
716 | unsigned int idx = cmd_idx(cmd); | |
717 | ||
718 | return (idx >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[idx].fn; | |
719 | } | |
720 | ||
721 | /* ioctl dispatcher */ | |
722 | static int _autofs_dev_ioctl(unsigned int command, struct autofs_dev_ioctl __user *user) | |
723 | { | |
724 | struct autofs_dev_ioctl *param; | |
725 | struct file *fp; | |
726 | struct autofs_sb_info *sbi; | |
727 | unsigned int cmd_first, cmd; | |
728 | ioctl_fn fn = NULL; | |
729 | int err = 0; | |
730 | ||
731 | /* only root can play with this */ | |
732 | if (!capable(CAP_SYS_ADMIN)) | |
733 | return -EPERM; | |
734 | ||
735 | cmd_first = _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST); | |
736 | cmd = _IOC_NR(command); | |
737 | ||
738 | if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) || | |
739 | cmd - cmd_first >= AUTOFS_DEV_IOCTL_IOC_COUNT) { | |
740 | return -ENOTTY; | |
741 | } | |
742 | ||
743 | /* Copy the parameters into kernel space. */ | |
744 | param = copy_dev_ioctl(user); | |
745 | if (IS_ERR(param)) | |
746 | return PTR_ERR(param); | |
747 | ||
748 | err = validate_dev_ioctl(command, param); | |
749 | if (err) | |
750 | goto out; | |
751 | ||
752 | /* The validate routine above always sets the version */ | |
753 | if (cmd == AUTOFS_DEV_IOCTL_VERSION_CMD) | |
754 | goto done; | |
755 | ||
756 | fn = lookup_dev_ioctl(cmd); | |
757 | if (!fn) { | |
758 | AUTOFS_WARN("unknown command 0x%08x", command); | |
759 | return -ENOTTY; | |
760 | } | |
761 | ||
762 | fp = NULL; | |
763 | sbi = NULL; | |
764 | ||
765 | /* | |
766 | * For obvious reasons the openmount can't have a file | |
767 | * descriptor yet. We don't take a reference to the | |
768 | * file during close to allow for immediate release. | |
769 | */ | |
770 | if (cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD && | |
771 | cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) { | |
772 | fp = fget(param->ioctlfd); | |
773 | if (!fp) { | |
774 | if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) | |
775 | goto cont; | |
776 | err = -EBADF; | |
777 | goto out; | |
778 | } | |
779 | ||
780 | if (!fp->f_op) { | |
781 | err = -ENOTTY; | |
782 | fput(fp); | |
783 | goto out; | |
784 | } | |
785 | ||
786 | sbi = autofs_dev_ioctl_sbi(fp); | |
787 | if (!sbi || sbi->magic != AUTOFS_SBI_MAGIC) { | |
788 | err = -EINVAL; | |
789 | fput(fp); | |
790 | goto out; | |
791 | } | |
792 | ||
793 | /* | |
794 | * Admin needs to be able to set the mount catatonic in | |
795 | * order to be able to perform the re-open. | |
796 | */ | |
797 | if (!autofs4_oz_mode(sbi) && | |
798 | cmd != AUTOFS_DEV_IOCTL_CATATONIC_CMD) { | |
799 | err = -EACCES; | |
800 | fput(fp); | |
801 | goto out; | |
802 | } | |
803 | } | |
804 | cont: | |
805 | err = fn(fp, sbi, param); | |
806 | ||
807 | if (fp) | |
808 | fput(fp); | |
809 | done: | |
810 | if (err >= 0 && copy_to_user(user, param, AUTOFS_DEV_IOCTL_SIZE)) | |
811 | err = -EFAULT; | |
812 | out: | |
813 | free_dev_ioctl(param); | |
814 | return err; | |
815 | } | |
816 | ||
817 | static long autofs_dev_ioctl(struct file *file, uint command, ulong u) | |
818 | { | |
819 | int err; | |
820 | err = _autofs_dev_ioctl(command, (struct autofs_dev_ioctl __user *) u); | |
821 | return (long) err; | |
822 | } | |
823 | ||
824 | #ifdef CONFIG_COMPAT | |
825 | static long autofs_dev_ioctl_compat(struct file *file, uint command, ulong u) | |
826 | { | |
827 | return (long) autofs_dev_ioctl(file, command, (ulong) compat_ptr(u)); | |
828 | } | |
829 | #else | |
830 | #define autofs_dev_ioctl_compat NULL | |
831 | #endif | |
832 | ||
833 | static const struct file_operations _dev_ioctl_fops = { | |
834 | .unlocked_ioctl = autofs_dev_ioctl, | |
835 | .compat_ioctl = autofs_dev_ioctl_compat, | |
836 | .owner = THIS_MODULE, | |
837 | }; | |
838 | ||
839 | static struct miscdevice _autofs_dev_ioctl_misc = { | |
840 | .minor = MISC_DYNAMIC_MINOR, | |
841 | .name = AUTOFS_DEVICE_NAME, | |
842 | .fops = &_dev_ioctl_fops | |
843 | }; | |
844 | ||
845 | /* Register/deregister misc character device */ | |
846 | int autofs_dev_ioctl_init(void) | |
847 | { | |
848 | int r; | |
849 | ||
850 | r = misc_register(&_autofs_dev_ioctl_misc); | |
851 | if (r) { | |
852 | AUTOFS_ERROR("misc_register failed for control device"); | |
853 | return r; | |
854 | } | |
855 | ||
856 | return 0; | |
857 | } | |
858 | ||
859 | void autofs_dev_ioctl_exit(void) | |
860 | { | |
861 | misc_deregister(&_autofs_dev_ioctl_misc); | |
862 | return; | |
863 | } | |
864 |