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> | |
8d7b48e0 IK |
22 | #include <linux/magic.h> |
23 | #include <linux/dcache.h> | |
24 | #include <linux/uaccess.h> | |
5a0e3ad6 | 25 | #include <linux/slab.h> |
8d7b48e0 IK |
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 | { | |
7ca5ca60 | 98 | struct autofs_dev_ioctl tmp; |
8d7b48e0 IK |
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 | ||
7ca5ca60 | 106 | return memdup_user(in, tmp.size); |
8d7b48e0 IK |
107 | } |
108 | ||
109 | static inline void free_dev_ioctl(struct autofs_dev_ioctl *param) | |
110 | { | |
111 | kfree(param); | |
112 | return; | |
113 | } | |
114 | ||
115 | /* | |
116 | * Check sanity of parameter control fields and if a path is present | |
bae8ec66 | 117 | * check that it is terminated and contains at least one "/". |
8d7b48e0 IK |
118 | */ |
119 | static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param) | |
120 | { | |
96b03179 | 121 | int err; |
8d7b48e0 | 122 | |
96b03179 IK |
123 | err = check_dev_ioctl_version(cmd, param); |
124 | if (err) { | |
8d7b48e0 IK |
125 | AUTOFS_WARN("invalid device control module version " |
126 | "supplied for cmd(0x%08x)", cmd); | |
127 | goto out; | |
128 | } | |
129 | ||
130 | if (param->size > sizeof(*param)) { | |
3eac8778 | 131 | err = invalid_str(param->path, param->size - sizeof(*param)); |
8d7b48e0 | 132 | if (err) { |
bae8ec66 IK |
133 | AUTOFS_WARN( |
134 | "path string terminator missing for cmd(0x%08x)", | |
135 | cmd); | |
8d7b48e0 IK |
136 | goto out; |
137 | } | |
138 | ||
bae8ec66 | 139 | err = check_name(param->path); |
8d7b48e0 IK |
140 | if (err) { |
141 | AUTOFS_WARN("invalid path supplied for cmd(0x%08x)", | |
142 | cmd); | |
143 | goto out; | |
144 | } | |
145 | } | |
146 | ||
147 | err = 0; | |
148 | out: | |
149 | return err; | |
150 | } | |
151 | ||
152 | /* | |
153 | * Get the autofs super block info struct from the file opened on | |
154 | * the autofs mount point. | |
155 | */ | |
156 | static struct autofs_sb_info *autofs_dev_ioctl_sbi(struct file *f) | |
157 | { | |
158 | struct autofs_sb_info *sbi = NULL; | |
159 | struct inode *inode; | |
160 | ||
161 | if (f) { | |
496ad9aa | 162 | inode = file_inode(f); |
8d7b48e0 IK |
163 | sbi = autofs4_sbi(inode->i_sb); |
164 | } | |
165 | return sbi; | |
166 | } | |
167 | ||
168 | /* Return autofs module protocol version */ | |
169 | static int autofs_dev_ioctl_protover(struct file *fp, | |
170 | struct autofs_sb_info *sbi, | |
171 | struct autofs_dev_ioctl *param) | |
172 | { | |
730c9eec | 173 | param->protover.version = sbi->version; |
8d7b48e0 IK |
174 | return 0; |
175 | } | |
176 | ||
177 | /* Return autofs module protocol sub version */ | |
178 | static int autofs_dev_ioctl_protosubver(struct file *fp, | |
179 | struct autofs_sb_info *sbi, | |
180 | struct autofs_dev_ioctl *param) | |
181 | { | |
730c9eec | 182 | param->protosubver.sub_version = sbi->sub_version; |
8d7b48e0 IK |
183 | return 0; |
184 | } | |
185 | ||
ac838719 | 186 | /* Find the topmost mount satisfying test() */ |
4e44b685 AV |
187 | static int find_autofs_mount(const char *pathname, |
188 | struct path *res, | |
189 | int test(struct path *path, void *data), | |
190 | void *data) | |
8d7b48e0 | 191 | { |
4e44b685 | 192 | struct path path; |
ac838719 | 193 | int err = kern_path_mountpoint(AT_FDCWD, pathname, &path, 0); |
4e44b685 AV |
194 | if (err) |
195 | return err; | |
8d7b48e0 | 196 | err = -ENOENT; |
4e44b685 | 197 | while (path.dentry == path.mnt->mnt_root) { |
d8c9584e | 198 | if (path.dentry->d_sb->s_magic == AUTOFS_SUPER_MAGIC) { |
4e44b685 AV |
199 | if (test(&path, data)) { |
200 | path_get(&path); | |
4e44b685 | 201 | *res = path; |
8d7b48e0 | 202 | err = 0; |
ac838719 | 203 | break; |
8d7b48e0 IK |
204 | } |
205 | } | |
bab77ebf | 206 | if (!follow_up(&path)) |
4e44b685 | 207 | break; |
8d7b48e0 | 208 | } |
4e44b685 | 209 | path_put(&path); |
8d7b48e0 IK |
210 | return err; |
211 | } | |
212 | ||
4e44b685 | 213 | static int test_by_dev(struct path *path, void *p) |
8d7b48e0 | 214 | { |
d8c9584e | 215 | return path->dentry->d_sb->s_dev == *(dev_t *)p; |
4e44b685 | 216 | } |
8d7b48e0 | 217 | |
4e44b685 AV |
218 | static int test_by_type(struct path *path, void *p) |
219 | { | |
220 | struct autofs_info *ino = autofs4_dentry_ino(path->dentry); | |
221 | return ino && ino->sbi->type & *(unsigned *)p; | |
8d7b48e0 IK |
222 | } |
223 | ||
8d7b48e0 IK |
224 | /* |
225 | * Open a file descriptor on the autofs mount point corresponding | |
226 | * to the given path and device number (aka. new_encode_dev(sb->s_dev)). | |
227 | */ | |
4e44b685 | 228 | static int autofs_dev_ioctl_open_mountpoint(const char *name, dev_t devid) |
8d7b48e0 | 229 | { |
8d7b48e0 IK |
230 | int err, fd; |
231 | ||
c921b40d | 232 | fd = get_unused_fd_flags(O_CLOEXEC); |
8d7b48e0 | 233 | if (likely(fd >= 0)) { |
4e44b685 AV |
234 | struct file *filp; |
235 | struct path path; | |
236 | ||
237 | err = find_autofs_mount(name, &path, test_by_dev, &devid); | |
8d7b48e0 IK |
238 | if (err) |
239 | goto out; | |
240 | ||
241 | /* | |
4e44b685 | 242 | * Find autofs super block that has the device number |
8d7b48e0 IK |
243 | * corresponding to the autofs fs we want to open. |
244 | */ | |
8d7b48e0 | 245 | |
765927b2 AV |
246 | filp = dentry_open(&path, O_RDONLY, current_cred()); |
247 | path_put(&path); | |
8d7b48e0 IK |
248 | if (IS_ERR(filp)) { |
249 | err = PTR_ERR(filp); | |
250 | goto out; | |
251 | } | |
252 | ||
c921b40d | 253 | fd_install(fd, filp); |
8d7b48e0 IK |
254 | } |
255 | ||
256 | return fd; | |
257 | ||
258 | out: | |
259 | put_unused_fd(fd); | |
260 | return err; | |
261 | } | |
262 | ||
263 | /* Open a file descriptor on an autofs mount point */ | |
264 | static int autofs_dev_ioctl_openmount(struct file *fp, | |
265 | struct autofs_sb_info *sbi, | |
266 | struct autofs_dev_ioctl *param) | |
267 | { | |
268 | const char *path; | |
269 | dev_t devid; | |
270 | int err, fd; | |
271 | ||
272 | /* param->path has already been checked */ | |
730c9eec | 273 | if (!param->openmount.devid) |
8d7b48e0 IK |
274 | return -EINVAL; |
275 | ||
276 | param->ioctlfd = -1; | |
277 | ||
278 | path = param->path; | |
4e44b685 | 279 | devid = new_decode_dev(param->openmount.devid); |
8d7b48e0 IK |
280 | |
281 | err = 0; | |
282 | fd = autofs_dev_ioctl_open_mountpoint(path, devid); | |
283 | if (unlikely(fd < 0)) { | |
284 | err = fd; | |
285 | goto out; | |
286 | } | |
287 | ||
288 | param->ioctlfd = fd; | |
289 | out: | |
290 | return err; | |
291 | } | |
292 | ||
293 | /* Close file descriptor allocated above (user can also use close(2)). */ | |
294 | static int autofs_dev_ioctl_closemount(struct file *fp, | |
295 | struct autofs_sb_info *sbi, | |
296 | struct autofs_dev_ioctl *param) | |
297 | { | |
298 | return sys_close(param->ioctlfd); | |
299 | } | |
300 | ||
301 | /* | |
302 | * Send "ready" status for an existing wait (either a mount or an expire | |
303 | * request). | |
304 | */ | |
305 | static int autofs_dev_ioctl_ready(struct file *fp, | |
306 | struct autofs_sb_info *sbi, | |
307 | struct autofs_dev_ioctl *param) | |
308 | { | |
309 | autofs_wqt_t token; | |
310 | ||
730c9eec | 311 | token = (autofs_wqt_t) param->ready.token; |
8d7b48e0 IK |
312 | return autofs4_wait_release(sbi, token, 0); |
313 | } | |
314 | ||
315 | /* | |
316 | * Send "fail" status for an existing wait (either a mount or an expire | |
317 | * request). | |
318 | */ | |
319 | static int autofs_dev_ioctl_fail(struct file *fp, | |
320 | struct autofs_sb_info *sbi, | |
321 | struct autofs_dev_ioctl *param) | |
322 | { | |
323 | autofs_wqt_t token; | |
324 | int status; | |
325 | ||
730c9eec IK |
326 | token = (autofs_wqt_t) param->fail.token; |
327 | status = param->fail.status ? param->fail.status : -ENOENT; | |
8d7b48e0 IK |
328 | return autofs4_wait_release(sbi, token, status); |
329 | } | |
330 | ||
331 | /* | |
332 | * Set the pipe fd for kernel communication to the daemon. | |
333 | * | |
334 | * Normally this is set at mount using an option but if we | |
335 | * are reconnecting to a busy mount then we need to use this | |
336 | * to tell the autofs mount about the new kernel pipe fd. In | |
337 | * order to protect mounts against incorrectly setting the | |
338 | * pipefd we also require that the autofs mount be catatonic. | |
339 | * | |
340 | * This also sets the process group id used to identify the | |
341 | * controlling process (eg. the owning automount(8) daemon). | |
342 | */ | |
343 | static int autofs_dev_ioctl_setpipefd(struct file *fp, | |
344 | struct autofs_sb_info *sbi, | |
345 | struct autofs_dev_ioctl *param) | |
346 | { | |
347 | int pipefd; | |
348 | int err = 0; | |
349 | ||
730c9eec | 350 | if (param->setpipefd.pipefd == -1) |
8d7b48e0 IK |
351 | return -EINVAL; |
352 | ||
730c9eec | 353 | pipefd = param->setpipefd.pipefd; |
8d7b48e0 IK |
354 | |
355 | mutex_lock(&sbi->wq_mutex); | |
356 | if (!sbi->catatonic) { | |
357 | mutex_unlock(&sbi->wq_mutex); | |
358 | return -EBUSY; | |
359 | } else { | |
360 | struct file *pipe = fget(pipefd); | |
3dc8fe4d JJ |
361 | if (!pipe) { |
362 | err = -EBADF; | |
363 | goto out; | |
364 | } | |
64f371bc | 365 | if (autofs_prepare_pipe(pipe) < 0) { |
8d7b48e0 IK |
366 | err = -EPIPE; |
367 | fput(pipe); | |
368 | goto out; | |
369 | } | |
370 | sbi->oz_pgrp = task_pgrp_nr(current); | |
371 | sbi->pipefd = pipefd; | |
372 | sbi->pipe = pipe; | |
373 | sbi->catatonic = 0; | |
374 | } | |
375 | out: | |
376 | mutex_unlock(&sbi->wq_mutex); | |
377 | return err; | |
378 | } | |
379 | ||
380 | /* | |
381 | * Make the autofs mount point catatonic, no longer responsive to | |
382 | * mount requests. Also closes the kernel pipe file descriptor. | |
383 | */ | |
384 | static int autofs_dev_ioctl_catatonic(struct file *fp, | |
385 | struct autofs_sb_info *sbi, | |
386 | struct autofs_dev_ioctl *param) | |
387 | { | |
388 | autofs4_catatonic_mode(sbi); | |
389 | return 0; | |
390 | } | |
391 | ||
392 | /* Set the autofs mount timeout */ | |
393 | static int autofs_dev_ioctl_timeout(struct file *fp, | |
394 | struct autofs_sb_info *sbi, | |
395 | struct autofs_dev_ioctl *param) | |
396 | { | |
397 | unsigned long timeout; | |
398 | ||
730c9eec IK |
399 | timeout = param->timeout.timeout; |
400 | param->timeout.timeout = sbi->exp_timeout / HZ; | |
8d7b48e0 IK |
401 | sbi->exp_timeout = timeout * HZ; |
402 | return 0; | |
403 | } | |
404 | ||
405 | /* | |
406 | * Return the uid and gid of the last request for the mount | |
407 | * | |
408 | * When reconstructing an autofs mount tree with active mounts | |
409 | * we need to re-connect to mounts that may have used the original | |
410 | * process uid and gid (or string variations of them) for mount | |
411 | * lookups within the map entry. | |
412 | */ | |
413 | static int autofs_dev_ioctl_requester(struct file *fp, | |
414 | struct autofs_sb_info *sbi, | |
415 | struct autofs_dev_ioctl *param) | |
416 | { | |
417 | struct autofs_info *ino; | |
4e44b685 | 418 | struct path path; |
8d7b48e0 IK |
419 | dev_t devid; |
420 | int err = -ENOENT; | |
421 | ||
422 | if (param->size <= sizeof(*param)) { | |
423 | err = -EINVAL; | |
424 | goto out; | |
425 | } | |
426 | ||
4e44b685 | 427 | devid = sbi->sb->s_dev; |
8d7b48e0 | 428 | |
730c9eec | 429 | param->requester.uid = param->requester.gid = -1; |
8d7b48e0 | 430 | |
4e44b685 | 431 | err = find_autofs_mount(param->path, &path, test_by_dev, &devid); |
8d7b48e0 IK |
432 | if (err) |
433 | goto out; | |
434 | ||
4e44b685 | 435 | ino = autofs4_dentry_ino(path.dentry); |
8d7b48e0 IK |
436 | if (ino) { |
437 | err = 0; | |
4e44b685 | 438 | autofs4_expire_wait(path.dentry); |
8d7b48e0 | 439 | spin_lock(&sbi->fs_lock); |
45634cd8 EB |
440 | param->requester.uid = from_kuid_munged(current_user_ns(), ino->uid); |
441 | param->requester.gid = from_kgid_munged(current_user_ns(), ino->gid); | |
8d7b48e0 IK |
442 | spin_unlock(&sbi->fs_lock); |
443 | } | |
4e44b685 | 444 | path_put(&path); |
8d7b48e0 IK |
445 | out: |
446 | return err; | |
447 | } | |
448 | ||
449 | /* | |
450 | * Call repeatedly until it returns -EAGAIN, meaning there's nothing | |
451 | * more that can be done. | |
452 | */ | |
453 | static int autofs_dev_ioctl_expire(struct file *fp, | |
454 | struct autofs_sb_info *sbi, | |
455 | struct autofs_dev_ioctl *param) | |
456 | { | |
8d7b48e0 | 457 | struct vfsmount *mnt; |
8d7b48e0 IK |
458 | int how; |
459 | ||
730c9eec | 460 | how = param->expire.how; |
8d7b48e0 IK |
461 | mnt = fp->f_path.mnt; |
462 | ||
56fcef75 | 463 | return autofs4_do_expire_multi(sbi->sb, mnt, sbi, how); |
8d7b48e0 IK |
464 | } |
465 | ||
466 | /* Check if autofs mount point is in use */ | |
467 | static int autofs_dev_ioctl_askumount(struct file *fp, | |
468 | struct autofs_sb_info *sbi, | |
469 | struct autofs_dev_ioctl *param) | |
470 | { | |
730c9eec | 471 | param->askumount.may_umount = 0; |
8d7b48e0 | 472 | if (may_umount(fp->f_path.mnt)) |
730c9eec | 473 | param->askumount.may_umount = 1; |
8d7b48e0 IK |
474 | return 0; |
475 | } | |
476 | ||
477 | /* | |
478 | * Check if the given path is a mountpoint. | |
479 | * | |
480 | * If we are supplied with the file descriptor of an autofs | |
481 | * mount we're looking for a specific mount. In this case | |
482 | * the path is considered a mountpoint if it is itself a | |
483 | * mountpoint or contains a mount, such as a multi-mount | |
484 | * without a root mount. In this case we return 1 if the | |
485 | * path is a mount point and the super magic of the covering | |
486 | * mount if there is one or 0 if it isn't a mountpoint. | |
487 | * | |
488 | * If we aren't supplied with a file descriptor then we | |
ac838719 IK |
489 | * lookup the path and check if it is the root of a mount. |
490 | * If a type is given we are looking for a particular autofs | |
491 | * mount and if we don't find a match we return fail. If the | |
492 | * located path is the root of a mount we return 1 along with | |
493 | * the super magic of the mount or 0 otherwise. | |
8d7b48e0 IK |
494 | * |
495 | * In both cases the the device number (as returned by | |
496 | * new_encode_dev()) is also returned. | |
497 | */ | |
498 | static int autofs_dev_ioctl_ismountpoint(struct file *fp, | |
499 | struct autofs_sb_info *sbi, | |
500 | struct autofs_dev_ioctl *param) | |
501 | { | |
4e44b685 AV |
502 | struct path path; |
503 | const char *name; | |
8d7b48e0 | 504 | unsigned int type; |
730c9eec | 505 | unsigned int devid, magic; |
8d7b48e0 IK |
506 | int err = -ENOENT; |
507 | ||
508 | if (param->size <= sizeof(*param)) { | |
509 | err = -EINVAL; | |
510 | goto out; | |
511 | } | |
512 | ||
4e44b685 | 513 | name = param->path; |
730c9eec | 514 | type = param->ismountpoint.in.type; |
8d7b48e0 | 515 | |
730c9eec IK |
516 | param->ismountpoint.out.devid = devid = 0; |
517 | param->ismountpoint.out.magic = magic = 0; | |
8d7b48e0 IK |
518 | |
519 | if (!fp || param->ioctlfd == -1) { | |
4e44b685 | 520 | if (autofs_type_any(type)) |
ac838719 IK |
521 | err = kern_path_mountpoint(AT_FDCWD, |
522 | name, &path, LOOKUP_FOLLOW); | |
4e44b685 | 523 | else |
ac838719 IK |
524 | err = find_autofs_mount(name, &path, |
525 | test_by_type, &type); | |
4e44b685 AV |
526 | if (err) |
527 | goto out; | |
d8c9584e | 528 | devid = new_encode_dev(path.dentry->d_sb->s_dev); |
8d7b48e0 | 529 | err = 0; |
f598f9f1 | 530 | if (path.mnt->mnt_root == path.dentry) { |
8d7b48e0 | 531 | err = 1; |
d8c9584e | 532 | magic = path.dentry->d_sb->s_magic; |
8d7b48e0 IK |
533 | } |
534 | } else { | |
4e44b685 | 535 | dev_t dev = sbi->sb->s_dev; |
8d7b48e0 | 536 | |
4e44b685 | 537 | err = find_autofs_mount(name, &path, test_by_dev, &dev); |
8d7b48e0 IK |
538 | if (err) |
539 | goto out; | |
540 | ||
4e44b685 | 541 | devid = new_encode_dev(dev); |
8d7b48e0 | 542 | |
4e44b685 | 543 | err = have_submounts(path.dentry); |
8d7b48e0 | 544 | |
cc53ce53 | 545 | if (follow_down_one(&path)) |
d8c9584e | 546 | magic = path.dentry->d_sb->s_magic; |
8d7b48e0 IK |
547 | } |
548 | ||
730c9eec IK |
549 | param->ismountpoint.out.devid = devid; |
550 | param->ismountpoint.out.magic = magic; | |
4e44b685 | 551 | path_put(&path); |
8d7b48e0 IK |
552 | out: |
553 | return err; | |
554 | } | |
555 | ||
556 | /* | |
557 | * Our range of ioctl numbers isn't 0 based so we need to shift | |
558 | * the array index by _IOC_NR(AUTOFS_CTL_IOC_FIRST) for the table | |
559 | * lookup. | |
560 | */ | |
561 | #define cmd_idx(cmd) (cmd - _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST)) | |
562 | ||
563 | static ioctl_fn lookup_dev_ioctl(unsigned int cmd) | |
564 | { | |
565 | static struct { | |
566 | int cmd; | |
567 | ioctl_fn fn; | |
568 | } _ioctls[] = { | |
569 | {cmd_idx(AUTOFS_DEV_IOCTL_VERSION_CMD), NULL}, | |
570 | {cmd_idx(AUTOFS_DEV_IOCTL_PROTOVER_CMD), | |
571 | autofs_dev_ioctl_protover}, | |
572 | {cmd_idx(AUTOFS_DEV_IOCTL_PROTOSUBVER_CMD), | |
573 | autofs_dev_ioctl_protosubver}, | |
574 | {cmd_idx(AUTOFS_DEV_IOCTL_OPENMOUNT_CMD), | |
575 | autofs_dev_ioctl_openmount}, | |
576 | {cmd_idx(AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD), | |
577 | autofs_dev_ioctl_closemount}, | |
578 | {cmd_idx(AUTOFS_DEV_IOCTL_READY_CMD), | |
579 | autofs_dev_ioctl_ready}, | |
580 | {cmd_idx(AUTOFS_DEV_IOCTL_FAIL_CMD), | |
581 | autofs_dev_ioctl_fail}, | |
582 | {cmd_idx(AUTOFS_DEV_IOCTL_SETPIPEFD_CMD), | |
583 | autofs_dev_ioctl_setpipefd}, | |
584 | {cmd_idx(AUTOFS_DEV_IOCTL_CATATONIC_CMD), | |
585 | autofs_dev_ioctl_catatonic}, | |
586 | {cmd_idx(AUTOFS_DEV_IOCTL_TIMEOUT_CMD), | |
587 | autofs_dev_ioctl_timeout}, | |
588 | {cmd_idx(AUTOFS_DEV_IOCTL_REQUESTER_CMD), | |
589 | autofs_dev_ioctl_requester}, | |
590 | {cmd_idx(AUTOFS_DEV_IOCTL_EXPIRE_CMD), | |
591 | autofs_dev_ioctl_expire}, | |
592 | {cmd_idx(AUTOFS_DEV_IOCTL_ASKUMOUNT_CMD), | |
593 | autofs_dev_ioctl_askumount}, | |
594 | {cmd_idx(AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD), | |
595 | autofs_dev_ioctl_ismountpoint} | |
596 | }; | |
597 | unsigned int idx = cmd_idx(cmd); | |
598 | ||
599 | return (idx >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[idx].fn; | |
600 | } | |
601 | ||
602 | /* ioctl dispatcher */ | |
603 | static int _autofs_dev_ioctl(unsigned int command, struct autofs_dev_ioctl __user *user) | |
604 | { | |
605 | struct autofs_dev_ioctl *param; | |
606 | struct file *fp; | |
607 | struct autofs_sb_info *sbi; | |
608 | unsigned int cmd_first, cmd; | |
609 | ioctl_fn fn = NULL; | |
610 | int err = 0; | |
611 | ||
612 | /* only root can play with this */ | |
613 | if (!capable(CAP_SYS_ADMIN)) | |
614 | return -EPERM; | |
615 | ||
616 | cmd_first = _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST); | |
617 | cmd = _IOC_NR(command); | |
618 | ||
619 | if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) || | |
620 | cmd - cmd_first >= AUTOFS_DEV_IOCTL_IOC_COUNT) { | |
621 | return -ENOTTY; | |
622 | } | |
623 | ||
624 | /* Copy the parameters into kernel space. */ | |
625 | param = copy_dev_ioctl(user); | |
626 | if (IS_ERR(param)) | |
627 | return PTR_ERR(param); | |
628 | ||
629 | err = validate_dev_ioctl(command, param); | |
630 | if (err) | |
631 | goto out; | |
632 | ||
633 | /* The validate routine above always sets the version */ | |
634 | if (cmd == AUTOFS_DEV_IOCTL_VERSION_CMD) | |
635 | goto done; | |
636 | ||
637 | fn = lookup_dev_ioctl(cmd); | |
638 | if (!fn) { | |
639 | AUTOFS_WARN("unknown command 0x%08x", command); | |
640 | return -ENOTTY; | |
641 | } | |
642 | ||
643 | fp = NULL; | |
644 | sbi = NULL; | |
645 | ||
646 | /* | |
647 | * For obvious reasons the openmount can't have a file | |
648 | * descriptor yet. We don't take a reference to the | |
649 | * file during close to allow for immediate release. | |
650 | */ | |
651 | if (cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD && | |
652 | cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) { | |
653 | fp = fget(param->ioctlfd); | |
654 | if (!fp) { | |
655 | if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) | |
656 | goto cont; | |
657 | err = -EBADF; | |
658 | goto out; | |
659 | } | |
660 | ||
661 | if (!fp->f_op) { | |
662 | err = -ENOTTY; | |
663 | fput(fp); | |
664 | goto out; | |
665 | } | |
666 | ||
667 | sbi = autofs_dev_ioctl_sbi(fp); | |
668 | if (!sbi || sbi->magic != AUTOFS_SBI_MAGIC) { | |
669 | err = -EINVAL; | |
670 | fput(fp); | |
671 | goto out; | |
672 | } | |
673 | ||
674 | /* | |
675 | * Admin needs to be able to set the mount catatonic in | |
676 | * order to be able to perform the re-open. | |
677 | */ | |
678 | if (!autofs4_oz_mode(sbi) && | |
679 | cmd != AUTOFS_DEV_IOCTL_CATATONIC_CMD) { | |
680 | err = -EACCES; | |
681 | fput(fp); | |
682 | goto out; | |
683 | } | |
684 | } | |
685 | cont: | |
686 | err = fn(fp, sbi, param); | |
687 | ||
688 | if (fp) | |
689 | fput(fp); | |
690 | done: | |
691 | if (err >= 0 && copy_to_user(user, param, AUTOFS_DEV_IOCTL_SIZE)) | |
692 | err = -EFAULT; | |
693 | out: | |
694 | free_dev_ioctl(param); | |
695 | return err; | |
696 | } | |
697 | ||
698 | static long autofs_dev_ioctl(struct file *file, uint command, ulong u) | |
699 | { | |
700 | int err; | |
701 | err = _autofs_dev_ioctl(command, (struct autofs_dev_ioctl __user *) u); | |
702 | return (long) err; | |
703 | } | |
704 | ||
705 | #ifdef CONFIG_COMPAT | |
706 | static long autofs_dev_ioctl_compat(struct file *file, uint command, ulong u) | |
707 | { | |
708 | return (long) autofs_dev_ioctl(file, command, (ulong) compat_ptr(u)); | |
709 | } | |
710 | #else | |
711 | #define autofs_dev_ioctl_compat NULL | |
712 | #endif | |
713 | ||
714 | static const struct file_operations _dev_ioctl_fops = { | |
715 | .unlocked_ioctl = autofs_dev_ioctl, | |
716 | .compat_ioctl = autofs_dev_ioctl_compat, | |
717 | .owner = THIS_MODULE, | |
6038f373 | 718 | .llseek = noop_llseek, |
8d7b48e0 IK |
719 | }; |
720 | ||
721 | static struct miscdevice _autofs_dev_ioctl_misc = { | |
578454ff | 722 | .minor = AUTOFS_MINOR, |
8d7b48e0 IK |
723 | .name = AUTOFS_DEVICE_NAME, |
724 | .fops = &_dev_ioctl_fops | |
725 | }; | |
726 | ||
578454ff KS |
727 | MODULE_ALIAS_MISCDEV(AUTOFS_MINOR); |
728 | MODULE_ALIAS("devname:autofs"); | |
729 | ||
8d7b48e0 IK |
730 | /* Register/deregister misc character device */ |
731 | int autofs_dev_ioctl_init(void) | |
732 | { | |
733 | int r; | |
734 | ||
735 | r = misc_register(&_autofs_dev_ioctl_misc); | |
736 | if (r) { | |
737 | AUTOFS_ERROR("misc_register failed for control device"); | |
738 | return r; | |
739 | } | |
740 | ||
741 | return 0; | |
742 | } | |
743 | ||
744 | void autofs_dev_ioctl_exit(void) | |
745 | { | |
746 | misc_deregister(&_autofs_dev_ioctl_misc); | |
747 | return; | |
748 | } | |
749 |