Commit | Line | Data |
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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 | */ | |
3eac8778 | 57 | static int invalid_str(char *str, size_t size) |
8d7b48e0 | 58 | { |
3eac8778 AV |
59 | if (memchr(str, 0, size)) |
60 | return 0; | |
8d7b48e0 IK |
61 | return -EINVAL; |
62 | } | |
63 | ||
64 | /* | |
65 | * Check that the user compiled against correct version of autofs | |
66 | * misc device code. | |
67 | * | |
68 | * As well as checking the version compatibility this always copies | |
69 | * the kernel interface version out. | |
70 | */ | |
71 | static int check_dev_ioctl_version(int cmd, struct autofs_dev_ioctl *param) | |
72 | { | |
73 | int err = 0; | |
74 | ||
75 | if ((AUTOFS_DEV_IOCTL_VERSION_MAJOR != param->ver_major) || | |
76 | (AUTOFS_DEV_IOCTL_VERSION_MINOR < param->ver_minor)) { | |
77 | AUTOFS_WARN("ioctl control interface version mismatch: " | |
78 | "kernel(%u.%u), user(%u.%u), cmd(%d)", | |
79 | AUTOFS_DEV_IOCTL_VERSION_MAJOR, | |
80 | AUTOFS_DEV_IOCTL_VERSION_MINOR, | |
81 | param->ver_major, param->ver_minor, cmd); | |
82 | err = -EINVAL; | |
83 | } | |
84 | ||
85 | /* Fill in the kernel version. */ | |
86 | param->ver_major = AUTOFS_DEV_IOCTL_VERSION_MAJOR; | |
87 | param->ver_minor = AUTOFS_DEV_IOCTL_VERSION_MINOR; | |
88 | ||
89 | return err; | |
90 | } | |
91 | ||
92 | /* | |
93 | * Copy parameter control struct, including a possible path allocated | |
94 | * at the end of the struct. | |
95 | */ | |
96 | static struct autofs_dev_ioctl *copy_dev_ioctl(struct autofs_dev_ioctl __user *in) | |
97 | { | |
98 | struct autofs_dev_ioctl tmp, *ads; | |
99 | ||
100 | if (copy_from_user(&tmp, in, sizeof(tmp))) | |
101 | return ERR_PTR(-EFAULT); | |
102 | ||
103 | if (tmp.size < sizeof(tmp)) | |
104 | return ERR_PTR(-EINVAL); | |
105 | ||
106 | ads = kmalloc(tmp.size, GFP_KERNEL); | |
107 | if (!ads) | |
108 | return ERR_PTR(-ENOMEM); | |
109 | ||
110 | if (copy_from_user(ads, in, tmp.size)) { | |
111 | kfree(ads); | |
112 | return ERR_PTR(-EFAULT); | |
113 | } | |
114 | ||
115 | return ads; | |
116 | } | |
117 | ||
118 | static inline void free_dev_ioctl(struct autofs_dev_ioctl *param) | |
119 | { | |
120 | kfree(param); | |
121 | return; | |
122 | } | |
123 | ||
124 | /* | |
125 | * Check sanity of parameter control fields and if a path is present | |
bae8ec66 | 126 | * check that it is terminated and contains at least one "/". |
8d7b48e0 IK |
127 | */ |
128 | static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param) | |
129 | { | |
96b03179 | 130 | int err; |
8d7b48e0 | 131 | |
96b03179 IK |
132 | err = check_dev_ioctl_version(cmd, param); |
133 | if (err) { | |
8d7b48e0 IK |
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)) { | |
3eac8778 | 140 | err = invalid_str(param->path, param->size - sizeof(*param)); |
8d7b48e0 | 141 | if (err) { |
bae8ec66 IK |
142 | AUTOFS_WARN( |
143 | "path string terminator missing for cmd(0x%08x)", | |
144 | cmd); | |
8d7b48e0 IK |
145 | goto out; |
146 | } | |
147 | ||
bae8ec66 | 148 | err = check_name(param->path); |
8d7b48e0 IK |
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 | { | |
730c9eec | 182 | param->protover.version = sbi->version; |
8d7b48e0 IK |
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 | { | |
730c9eec | 191 | param->protosubver.sub_version = sbi->sub_version; |
8d7b48e0 IK |
192 | return 0; |
193 | } | |
194 | ||
4e44b685 AV |
195 | static int find_autofs_mount(const char *pathname, |
196 | struct path *res, | |
197 | int test(struct path *path, void *data), | |
198 | void *data) | |
8d7b48e0 | 199 | { |
4e44b685 AV |
200 | struct path path; |
201 | int err = kern_path(pathname, 0, &path); | |
202 | if (err) | |
203 | return err; | |
8d7b48e0 | 204 | err = -ENOENT; |
4e44b685 AV |
205 | while (path.dentry == path.mnt->mnt_root) { |
206 | if (path.mnt->mnt_sb->s_magic == AUTOFS_SUPER_MAGIC) { | |
207 | if (test(&path, data)) { | |
208 | path_get(&path); | |
209 | if (!err) /* already found some */ | |
210 | path_put(res); | |
211 | *res = path; | |
8d7b48e0 | 212 | err = 0; |
8d7b48e0 IK |
213 | } |
214 | } | |
bab77ebf | 215 | if (!follow_up(&path)) |
4e44b685 | 216 | break; |
8d7b48e0 | 217 | } |
4e44b685 | 218 | path_put(&path); |
8d7b48e0 IK |
219 | return err; |
220 | } | |
221 | ||
4e44b685 | 222 | static int test_by_dev(struct path *path, void *p) |
8d7b48e0 | 223 | { |
4e44b685 AV |
224 | return path->mnt->mnt_sb->s_dev == *(dev_t *)p; |
225 | } | |
8d7b48e0 | 226 | |
4e44b685 AV |
227 | static int test_by_type(struct path *path, void *p) |
228 | { | |
229 | struct autofs_info *ino = autofs4_dentry_ino(path->dentry); | |
230 | return ino && ino->sbi->type & *(unsigned *)p; | |
8d7b48e0 IK |
231 | } |
232 | ||
233 | static void autofs_dev_ioctl_fd_install(unsigned int fd, struct file *file) | |
234 | { | |
235 | struct files_struct *files = current->files; | |
236 | struct fdtable *fdt; | |
237 | ||
238 | spin_lock(&files->file_lock); | |
239 | fdt = files_fdtable(files); | |
240 | BUG_ON(fdt->fd[fd] != NULL); | |
241 | rcu_assign_pointer(fdt->fd[fd], file); | |
242 | FD_SET(fd, fdt->close_on_exec); | |
243 | spin_unlock(&files->file_lock); | |
244 | } | |
245 | ||
246 | ||
247 | /* | |
248 | * Open a file descriptor on the autofs mount point corresponding | |
249 | * to the given path and device number (aka. new_encode_dev(sb->s_dev)). | |
250 | */ | |
4e44b685 | 251 | static int autofs_dev_ioctl_open_mountpoint(const char *name, dev_t devid) |
8d7b48e0 | 252 | { |
8d7b48e0 IK |
253 | int err, fd; |
254 | ||
255 | fd = get_unused_fd(); | |
256 | if (likely(fd >= 0)) { | |
4e44b685 AV |
257 | struct file *filp; |
258 | struct path path; | |
259 | ||
260 | err = find_autofs_mount(name, &path, test_by_dev, &devid); | |
8d7b48e0 IK |
261 | if (err) |
262 | goto out; | |
263 | ||
264 | /* | |
4e44b685 | 265 | * Find autofs super block that has the device number |
8d7b48e0 IK |
266 | * corresponding to the autofs fs we want to open. |
267 | */ | |
8d7b48e0 | 268 | |
4e44b685 | 269 | filp = dentry_open(path.dentry, path.mnt, O_RDONLY, |
745ca247 | 270 | current_cred()); |
8d7b48e0 IK |
271 | if (IS_ERR(filp)) { |
272 | err = PTR_ERR(filp); | |
273 | goto out; | |
274 | } | |
275 | ||
276 | autofs_dev_ioctl_fd_install(fd, filp); | |
277 | } | |
278 | ||
279 | return fd; | |
280 | ||
281 | out: | |
282 | put_unused_fd(fd); | |
283 | return err; | |
284 | } | |
285 | ||
286 | /* Open a file descriptor on an autofs mount point */ | |
287 | static int autofs_dev_ioctl_openmount(struct file *fp, | |
288 | struct autofs_sb_info *sbi, | |
289 | struct autofs_dev_ioctl *param) | |
290 | { | |
291 | const char *path; | |
292 | dev_t devid; | |
293 | int err, fd; | |
294 | ||
295 | /* param->path has already been checked */ | |
730c9eec | 296 | if (!param->openmount.devid) |
8d7b48e0 IK |
297 | return -EINVAL; |
298 | ||
299 | param->ioctlfd = -1; | |
300 | ||
301 | path = param->path; | |
4e44b685 | 302 | devid = new_decode_dev(param->openmount.devid); |
8d7b48e0 IK |
303 | |
304 | err = 0; | |
305 | fd = autofs_dev_ioctl_open_mountpoint(path, devid); | |
306 | if (unlikely(fd < 0)) { | |
307 | err = fd; | |
308 | goto out; | |
309 | } | |
310 | ||
311 | param->ioctlfd = fd; | |
312 | out: | |
313 | return err; | |
314 | } | |
315 | ||
316 | /* Close file descriptor allocated above (user can also use close(2)). */ | |
317 | static int autofs_dev_ioctl_closemount(struct file *fp, | |
318 | struct autofs_sb_info *sbi, | |
319 | struct autofs_dev_ioctl *param) | |
320 | { | |
321 | return sys_close(param->ioctlfd); | |
322 | } | |
323 | ||
324 | /* | |
325 | * Send "ready" status for an existing wait (either a mount or an expire | |
326 | * request). | |
327 | */ | |
328 | static int autofs_dev_ioctl_ready(struct file *fp, | |
329 | struct autofs_sb_info *sbi, | |
330 | struct autofs_dev_ioctl *param) | |
331 | { | |
332 | autofs_wqt_t token; | |
333 | ||
730c9eec | 334 | token = (autofs_wqt_t) param->ready.token; |
8d7b48e0 IK |
335 | return autofs4_wait_release(sbi, token, 0); |
336 | } | |
337 | ||
338 | /* | |
339 | * Send "fail" status for an existing wait (either a mount or an expire | |
340 | * request). | |
341 | */ | |
342 | static int autofs_dev_ioctl_fail(struct file *fp, | |
343 | struct autofs_sb_info *sbi, | |
344 | struct autofs_dev_ioctl *param) | |
345 | { | |
346 | autofs_wqt_t token; | |
347 | int status; | |
348 | ||
730c9eec IK |
349 | token = (autofs_wqt_t) param->fail.token; |
350 | status = param->fail.status ? param->fail.status : -ENOENT; | |
8d7b48e0 IK |
351 | return autofs4_wait_release(sbi, token, status); |
352 | } | |
353 | ||
354 | /* | |
355 | * Set the pipe fd for kernel communication to the daemon. | |
356 | * | |
357 | * Normally this is set at mount using an option but if we | |
358 | * are reconnecting to a busy mount then we need to use this | |
359 | * to tell the autofs mount about the new kernel pipe fd. In | |
360 | * order to protect mounts against incorrectly setting the | |
361 | * pipefd we also require that the autofs mount be catatonic. | |
362 | * | |
363 | * This also sets the process group id used to identify the | |
364 | * controlling process (eg. the owning automount(8) daemon). | |
365 | */ | |
366 | static int autofs_dev_ioctl_setpipefd(struct file *fp, | |
367 | struct autofs_sb_info *sbi, | |
368 | struct autofs_dev_ioctl *param) | |
369 | { | |
370 | int pipefd; | |
371 | int err = 0; | |
372 | ||
730c9eec | 373 | if (param->setpipefd.pipefd == -1) |
8d7b48e0 IK |
374 | return -EINVAL; |
375 | ||
730c9eec | 376 | pipefd = param->setpipefd.pipefd; |
8d7b48e0 IK |
377 | |
378 | mutex_lock(&sbi->wq_mutex); | |
379 | if (!sbi->catatonic) { | |
380 | mutex_unlock(&sbi->wq_mutex); | |
381 | return -EBUSY; | |
382 | } else { | |
383 | struct file *pipe = fget(pipefd); | |
384 | if (!pipe->f_op || !pipe->f_op->write) { | |
385 | err = -EPIPE; | |
386 | fput(pipe); | |
387 | goto out; | |
388 | } | |
389 | sbi->oz_pgrp = task_pgrp_nr(current); | |
390 | sbi->pipefd = pipefd; | |
391 | sbi->pipe = pipe; | |
392 | sbi->catatonic = 0; | |
393 | } | |
394 | out: | |
395 | mutex_unlock(&sbi->wq_mutex); | |
396 | return err; | |
397 | } | |
398 | ||
399 | /* | |
400 | * Make the autofs mount point catatonic, no longer responsive to | |
401 | * mount requests. Also closes the kernel pipe file descriptor. | |
402 | */ | |
403 | static int autofs_dev_ioctl_catatonic(struct file *fp, | |
404 | struct autofs_sb_info *sbi, | |
405 | struct autofs_dev_ioctl *param) | |
406 | { | |
407 | autofs4_catatonic_mode(sbi); | |
408 | return 0; | |
409 | } | |
410 | ||
411 | /* Set the autofs mount timeout */ | |
412 | static int autofs_dev_ioctl_timeout(struct file *fp, | |
413 | struct autofs_sb_info *sbi, | |
414 | struct autofs_dev_ioctl *param) | |
415 | { | |
416 | unsigned long timeout; | |
417 | ||
730c9eec IK |
418 | timeout = param->timeout.timeout; |
419 | param->timeout.timeout = sbi->exp_timeout / HZ; | |
8d7b48e0 IK |
420 | sbi->exp_timeout = timeout * HZ; |
421 | return 0; | |
422 | } | |
423 | ||
424 | /* | |
425 | * Return the uid and gid of the last request for the mount | |
426 | * | |
427 | * When reconstructing an autofs mount tree with active mounts | |
428 | * we need to re-connect to mounts that may have used the original | |
429 | * process uid and gid (or string variations of them) for mount | |
430 | * lookups within the map entry. | |
431 | */ | |
432 | static int autofs_dev_ioctl_requester(struct file *fp, | |
433 | struct autofs_sb_info *sbi, | |
434 | struct autofs_dev_ioctl *param) | |
435 | { | |
436 | struct autofs_info *ino; | |
4e44b685 | 437 | struct path path; |
8d7b48e0 IK |
438 | dev_t devid; |
439 | int err = -ENOENT; | |
440 | ||
441 | if (param->size <= sizeof(*param)) { | |
442 | err = -EINVAL; | |
443 | goto out; | |
444 | } | |
445 | ||
4e44b685 | 446 | devid = sbi->sb->s_dev; |
8d7b48e0 | 447 | |
730c9eec | 448 | param->requester.uid = param->requester.gid = -1; |
8d7b48e0 | 449 | |
4e44b685 | 450 | err = find_autofs_mount(param->path, &path, test_by_dev, &devid); |
8d7b48e0 IK |
451 | if (err) |
452 | goto out; | |
453 | ||
4e44b685 | 454 | ino = autofs4_dentry_ino(path.dentry); |
8d7b48e0 IK |
455 | if (ino) { |
456 | err = 0; | |
4e44b685 | 457 | autofs4_expire_wait(path.dentry); |
8d7b48e0 | 458 | spin_lock(&sbi->fs_lock); |
730c9eec IK |
459 | param->requester.uid = ino->uid; |
460 | param->requester.gid = ino->gid; | |
8d7b48e0 IK |
461 | spin_unlock(&sbi->fs_lock); |
462 | } | |
4e44b685 | 463 | path_put(&path); |
8d7b48e0 IK |
464 | out: |
465 | return err; | |
466 | } | |
467 | ||
468 | /* | |
469 | * Call repeatedly until it returns -EAGAIN, meaning there's nothing | |
470 | * more that can be done. | |
471 | */ | |
472 | static int autofs_dev_ioctl_expire(struct file *fp, | |
473 | struct autofs_sb_info *sbi, | |
474 | struct autofs_dev_ioctl *param) | |
475 | { | |
8d7b48e0 | 476 | struct vfsmount *mnt; |
8d7b48e0 IK |
477 | int how; |
478 | ||
730c9eec | 479 | how = param->expire.how; |
8d7b48e0 IK |
480 | mnt = fp->f_path.mnt; |
481 | ||
56fcef75 | 482 | return autofs4_do_expire_multi(sbi->sb, mnt, sbi, how); |
8d7b48e0 IK |
483 | } |
484 | ||
485 | /* Check if autofs mount point is in use */ | |
486 | static int autofs_dev_ioctl_askumount(struct file *fp, | |
487 | struct autofs_sb_info *sbi, | |
488 | struct autofs_dev_ioctl *param) | |
489 | { | |
730c9eec | 490 | param->askumount.may_umount = 0; |
8d7b48e0 | 491 | if (may_umount(fp->f_path.mnt)) |
730c9eec | 492 | param->askumount.may_umount = 1; |
8d7b48e0 IK |
493 | return 0; |
494 | } | |
495 | ||
496 | /* | |
497 | * Check if the given path is a mountpoint. | |
498 | * | |
499 | * If we are supplied with the file descriptor of an autofs | |
500 | * mount we're looking for a specific mount. In this case | |
501 | * the path is considered a mountpoint if it is itself a | |
502 | * mountpoint or contains a mount, such as a multi-mount | |
503 | * without a root mount. In this case we return 1 if the | |
504 | * path is a mount point and the super magic of the covering | |
505 | * mount if there is one or 0 if it isn't a mountpoint. | |
506 | * | |
507 | * If we aren't supplied with a file descriptor then we | |
508 | * lookup the nameidata of the path and check if it is the | |
509 | * root of a mount. If a type is given we are looking for | |
510 | * a particular autofs mount and if we don't find a match | |
511 | * we return fail. If the located nameidata path is the | |
512 | * root of a mount we return 1 along with the super magic | |
513 | * of the mount or 0 otherwise. | |
514 | * | |
515 | * In both cases the the device number (as returned by | |
516 | * new_encode_dev()) is also returned. | |
517 | */ | |
518 | static int autofs_dev_ioctl_ismountpoint(struct file *fp, | |
519 | struct autofs_sb_info *sbi, | |
520 | struct autofs_dev_ioctl *param) | |
521 | { | |
4e44b685 AV |
522 | struct path path; |
523 | const char *name; | |
8d7b48e0 | 524 | unsigned int type; |
730c9eec | 525 | unsigned int devid, magic; |
8d7b48e0 IK |
526 | int err = -ENOENT; |
527 | ||
528 | if (param->size <= sizeof(*param)) { | |
529 | err = -EINVAL; | |
530 | goto out; | |
531 | } | |
532 | ||
4e44b685 | 533 | name = param->path; |
730c9eec | 534 | type = param->ismountpoint.in.type; |
8d7b48e0 | 535 | |
730c9eec IK |
536 | param->ismountpoint.out.devid = devid = 0; |
537 | param->ismountpoint.out.magic = magic = 0; | |
8d7b48e0 IK |
538 | |
539 | if (!fp || param->ioctlfd == -1) { | |
4e44b685 AV |
540 | if (autofs_type_any(type)) |
541 | err = kern_path(name, LOOKUP_FOLLOW, &path); | |
542 | else | |
543 | err = find_autofs_mount(name, &path, test_by_type, &type); | |
544 | if (err) | |
545 | goto out; | |
546 | devid = new_encode_dev(path.mnt->mnt_sb->s_dev); | |
8d7b48e0 | 547 | err = 0; |
4e44b685 AV |
548 | if (path.dentry->d_inode && |
549 | path.mnt->mnt_root == path.dentry) { | |
8d7b48e0 | 550 | err = 1; |
4e44b685 | 551 | magic = path.dentry->d_inode->i_sb->s_magic; |
8d7b48e0 IK |
552 | } |
553 | } else { | |
4e44b685 | 554 | dev_t dev = sbi->sb->s_dev; |
8d7b48e0 | 555 | |
4e44b685 | 556 | err = find_autofs_mount(name, &path, test_by_dev, &dev); |
8d7b48e0 IK |
557 | if (err) |
558 | goto out; | |
559 | ||
4e44b685 | 560 | devid = new_encode_dev(dev); |
8d7b48e0 | 561 | |
4e44b685 | 562 | err = have_submounts(path.dentry); |
8d7b48e0 | 563 | |
4e44b685 | 564 | if (path.mnt->mnt_mountpoint != path.mnt->mnt_root) { |
9393bd07 | 565 | if (follow_down(&path)) |
4e44b685 | 566 | magic = path.mnt->mnt_sb->s_magic; |
8d7b48e0 IK |
567 | } |
568 | } | |
569 | ||
730c9eec IK |
570 | param->ismountpoint.out.devid = devid; |
571 | param->ismountpoint.out.magic = magic; | |
4e44b685 | 572 | path_put(&path); |
8d7b48e0 IK |
573 | out: |
574 | return err; | |
575 | } | |
576 | ||
577 | /* | |
578 | * Our range of ioctl numbers isn't 0 based so we need to shift | |
579 | * the array index by _IOC_NR(AUTOFS_CTL_IOC_FIRST) for the table | |
580 | * lookup. | |
581 | */ | |
582 | #define cmd_idx(cmd) (cmd - _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST)) | |
583 | ||
584 | static ioctl_fn lookup_dev_ioctl(unsigned int cmd) | |
585 | { | |
586 | static struct { | |
587 | int cmd; | |
588 | ioctl_fn fn; | |
589 | } _ioctls[] = { | |
590 | {cmd_idx(AUTOFS_DEV_IOCTL_VERSION_CMD), NULL}, | |
591 | {cmd_idx(AUTOFS_DEV_IOCTL_PROTOVER_CMD), | |
592 | autofs_dev_ioctl_protover}, | |
593 | {cmd_idx(AUTOFS_DEV_IOCTL_PROTOSUBVER_CMD), | |
594 | autofs_dev_ioctl_protosubver}, | |
595 | {cmd_idx(AUTOFS_DEV_IOCTL_OPENMOUNT_CMD), | |
596 | autofs_dev_ioctl_openmount}, | |
597 | {cmd_idx(AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD), | |
598 | autofs_dev_ioctl_closemount}, | |
599 | {cmd_idx(AUTOFS_DEV_IOCTL_READY_CMD), | |
600 | autofs_dev_ioctl_ready}, | |
601 | {cmd_idx(AUTOFS_DEV_IOCTL_FAIL_CMD), | |
602 | autofs_dev_ioctl_fail}, | |
603 | {cmd_idx(AUTOFS_DEV_IOCTL_SETPIPEFD_CMD), | |
604 | autofs_dev_ioctl_setpipefd}, | |
605 | {cmd_idx(AUTOFS_DEV_IOCTL_CATATONIC_CMD), | |
606 | autofs_dev_ioctl_catatonic}, | |
607 | {cmd_idx(AUTOFS_DEV_IOCTL_TIMEOUT_CMD), | |
608 | autofs_dev_ioctl_timeout}, | |
609 | {cmd_idx(AUTOFS_DEV_IOCTL_REQUESTER_CMD), | |
610 | autofs_dev_ioctl_requester}, | |
611 | {cmd_idx(AUTOFS_DEV_IOCTL_EXPIRE_CMD), | |
612 | autofs_dev_ioctl_expire}, | |
613 | {cmd_idx(AUTOFS_DEV_IOCTL_ASKUMOUNT_CMD), | |
614 | autofs_dev_ioctl_askumount}, | |
615 | {cmd_idx(AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD), | |
616 | autofs_dev_ioctl_ismountpoint} | |
617 | }; | |
618 | unsigned int idx = cmd_idx(cmd); | |
619 | ||
620 | return (idx >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[idx].fn; | |
621 | } | |
622 | ||
623 | /* ioctl dispatcher */ | |
624 | static int _autofs_dev_ioctl(unsigned int command, struct autofs_dev_ioctl __user *user) | |
625 | { | |
626 | struct autofs_dev_ioctl *param; | |
627 | struct file *fp; | |
628 | struct autofs_sb_info *sbi; | |
629 | unsigned int cmd_first, cmd; | |
630 | ioctl_fn fn = NULL; | |
631 | int err = 0; | |
632 | ||
633 | /* only root can play with this */ | |
634 | if (!capable(CAP_SYS_ADMIN)) | |
635 | return -EPERM; | |
636 | ||
637 | cmd_first = _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST); | |
638 | cmd = _IOC_NR(command); | |
639 | ||
640 | if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) || | |
641 | cmd - cmd_first >= AUTOFS_DEV_IOCTL_IOC_COUNT) { | |
642 | return -ENOTTY; | |
643 | } | |
644 | ||
645 | /* Copy the parameters into kernel space. */ | |
646 | param = copy_dev_ioctl(user); | |
647 | if (IS_ERR(param)) | |
648 | return PTR_ERR(param); | |
649 | ||
650 | err = validate_dev_ioctl(command, param); | |
651 | if (err) | |
652 | goto out; | |
653 | ||
654 | /* The validate routine above always sets the version */ | |
655 | if (cmd == AUTOFS_DEV_IOCTL_VERSION_CMD) | |
656 | goto done; | |
657 | ||
658 | fn = lookup_dev_ioctl(cmd); | |
659 | if (!fn) { | |
660 | AUTOFS_WARN("unknown command 0x%08x", command); | |
661 | return -ENOTTY; | |
662 | } | |
663 | ||
664 | fp = NULL; | |
665 | sbi = NULL; | |
666 | ||
667 | /* | |
668 | * For obvious reasons the openmount can't have a file | |
669 | * descriptor yet. We don't take a reference to the | |
670 | * file during close to allow for immediate release. | |
671 | */ | |
672 | if (cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD && | |
673 | cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) { | |
674 | fp = fget(param->ioctlfd); | |
675 | if (!fp) { | |
676 | if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) | |
677 | goto cont; | |
678 | err = -EBADF; | |
679 | goto out; | |
680 | } | |
681 | ||
682 | if (!fp->f_op) { | |
683 | err = -ENOTTY; | |
684 | fput(fp); | |
685 | goto out; | |
686 | } | |
687 | ||
688 | sbi = autofs_dev_ioctl_sbi(fp); | |
689 | if (!sbi || sbi->magic != AUTOFS_SBI_MAGIC) { | |
690 | err = -EINVAL; | |
691 | fput(fp); | |
692 | goto out; | |
693 | } | |
694 | ||
695 | /* | |
696 | * Admin needs to be able to set the mount catatonic in | |
697 | * order to be able to perform the re-open. | |
698 | */ | |
699 | if (!autofs4_oz_mode(sbi) && | |
700 | cmd != AUTOFS_DEV_IOCTL_CATATONIC_CMD) { | |
701 | err = -EACCES; | |
702 | fput(fp); | |
703 | goto out; | |
704 | } | |
705 | } | |
706 | cont: | |
707 | err = fn(fp, sbi, param); | |
708 | ||
709 | if (fp) | |
710 | fput(fp); | |
711 | done: | |
712 | if (err >= 0 && copy_to_user(user, param, AUTOFS_DEV_IOCTL_SIZE)) | |
713 | err = -EFAULT; | |
714 | out: | |
715 | free_dev_ioctl(param); | |
716 | return err; | |
717 | } | |
718 | ||
719 | static long autofs_dev_ioctl(struct file *file, uint command, ulong u) | |
720 | { | |
721 | int err; | |
722 | err = _autofs_dev_ioctl(command, (struct autofs_dev_ioctl __user *) u); | |
723 | return (long) err; | |
724 | } | |
725 | ||
726 | #ifdef CONFIG_COMPAT | |
727 | static long autofs_dev_ioctl_compat(struct file *file, uint command, ulong u) | |
728 | { | |
729 | return (long) autofs_dev_ioctl(file, command, (ulong) compat_ptr(u)); | |
730 | } | |
731 | #else | |
732 | #define autofs_dev_ioctl_compat NULL | |
733 | #endif | |
734 | ||
735 | static const struct file_operations _dev_ioctl_fops = { | |
736 | .unlocked_ioctl = autofs_dev_ioctl, | |
737 | .compat_ioctl = autofs_dev_ioctl_compat, | |
738 | .owner = THIS_MODULE, | |
739 | }; | |
740 | ||
741 | static struct miscdevice _autofs_dev_ioctl_misc = { | |
742 | .minor = MISC_DYNAMIC_MINOR, | |
743 | .name = AUTOFS_DEVICE_NAME, | |
744 | .fops = &_dev_ioctl_fops | |
745 | }; | |
746 | ||
747 | /* Register/deregister misc character device */ | |
748 | int autofs_dev_ioctl_init(void) | |
749 | { | |
750 | int r; | |
751 | ||
752 | r = misc_register(&_autofs_dev_ioctl_misc); | |
753 | if (r) { | |
754 | AUTOFS_ERROR("misc_register failed for control device"); | |
755 | return r; | |
756 | } | |
757 | ||
758 | return 0; | |
759 | } | |
760 | ||
761 | void autofs_dev_ioctl_exit(void) | |
762 | { | |
763 | misc_deregister(&_autofs_dev_ioctl_misc); | |
764 | return; | |
765 | } | |
766 |