blob: ac7d921ed9844b0a0c6afd0e6d4eaf4ca718f955 [file] [log] [blame]
Ian Kent8d7b48e2008-10-15 22:02:54 -07001/*
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>
Ian Kent8d7b48e2008-10-15 22:02:54 -070022#include <linux/magic.h>
23#include <linux/dcache.h>
24#include <linux/uaccess.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090025#include <linux/slab.h>
Ian Kent8d7b48e2008-10-15 22:02:54 -070026
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
43typedef int (*ioctl_fn)(struct file *, struct autofs_sb_info *,
44 struct autofs_dev_ioctl *);
45
46static 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 */
Al Viro3eac8772009-04-07 11:12:46 -040057static int invalid_str(char *str, size_t size)
Ian Kent8d7b48e2008-10-15 22:02:54 -070058{
Al Viro3eac8772009-04-07 11:12:46 -040059 if (memchr(str, 0, size))
60 return 0;
Ian Kent8d7b48e2008-10-15 22:02:54 -070061 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 */
71static 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 */
96static struct autofs_dev_ioctl *copy_dev_ioctl(struct autofs_dev_ioctl __user *in)
97{
Al Viro0a280962015-02-21 22:19:57 -050098 struct autofs_dev_ioctl tmp, *res;
Ian Kent8d7b48e2008-10-15 22:02:54 -070099
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
Sasha Levine53d77e2014-04-08 16:04:11 -0700106 if (tmp.size > (PATH_MAX + sizeof(tmp)))
107 return ERR_PTR(-ENAMETOOLONG);
108
Al Viro0a280962015-02-21 22:19:57 -0500109 res = memdup_user(in, tmp.size);
110 if (!IS_ERR(res))
111 res->size = tmp.size;
112
113 return res;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700114}
115
116static inline void free_dev_ioctl(struct autofs_dev_ioctl *param)
117{
118 kfree(param);
119 return;
120}
121
122/*
123 * Check sanity of parameter control fields and if a path is present
Ian Kentbae8ec62009-01-06 14:42:09 -0800124 * check that it is terminated and contains at least one "/".
Ian Kent8d7b48e2008-10-15 22:02:54 -0700125 */
126static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param)
127{
Ian Kent96b03172008-11-06 12:53:23 -0800128 int err;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700129
Ian Kent96b03172008-11-06 12:53:23 -0800130 err = check_dev_ioctl_version(cmd, param);
131 if (err) {
Ian Kent8d7b48e2008-10-15 22:02:54 -0700132 AUTOFS_WARN("invalid device control module version "
133 "supplied for cmd(0x%08x)", cmd);
134 goto out;
135 }
136
137 if (param->size > sizeof(*param)) {
Al Viro3eac8772009-04-07 11:12:46 -0400138 err = invalid_str(param->path, param->size - sizeof(*param));
Ian Kent8d7b48e2008-10-15 22:02:54 -0700139 if (err) {
Ian Kentbae8ec62009-01-06 14:42:09 -0800140 AUTOFS_WARN(
141 "path string terminator missing for cmd(0x%08x)",
142 cmd);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700143 goto out;
144 }
145
Ian Kentbae8ec62009-01-06 14:42:09 -0800146 err = check_name(param->path);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700147 if (err) {
148 AUTOFS_WARN("invalid path supplied for cmd(0x%08x)",
149 cmd);
150 goto out;
151 }
152 }
153
154 err = 0;
155out:
156 return err;
157}
158
159/*
160 * Get the autofs super block info struct from the file opened on
161 * the autofs mount point.
162 */
163static struct autofs_sb_info *autofs_dev_ioctl_sbi(struct file *f)
164{
165 struct autofs_sb_info *sbi = NULL;
166 struct inode *inode;
167
168 if (f) {
Al Viro496ad9a2013-01-23 17:07:38 -0500169 inode = file_inode(f);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700170 sbi = autofs4_sbi(inode->i_sb);
171 }
172 return sbi;
173}
174
175/* Return autofs module protocol version */
176static int autofs_dev_ioctl_protover(struct file *fp,
177 struct autofs_sb_info *sbi,
178 struct autofs_dev_ioctl *param)
179{
Ian Kent730c9ee2009-01-06 14:42:06 -0800180 param->protover.version = sbi->version;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700181 return 0;
182}
183
184/* Return autofs module protocol sub version */
185static int autofs_dev_ioctl_protosubver(struct file *fp,
186 struct autofs_sb_info *sbi,
187 struct autofs_dev_ioctl *param)
188{
Ian Kent730c9ee2009-01-06 14:42:06 -0800189 param->protosubver.sub_version = sbi->sub_version;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700190 return 0;
191}
192
Ian Kentac838712013-09-08 16:47:23 +0800193/* Find the topmost mount satisfying test() */
Al Viro4e44b682009-04-07 11:08:56 -0400194static int find_autofs_mount(const char *pathname,
195 struct path *res,
196 int test(struct path *path, void *data),
197 void *data)
Ian Kent8d7b48e2008-10-15 22:02:54 -0700198{
Al Viro4e44b682009-04-07 11:08:56 -0400199 struct path path;
Ian Kentac838712013-09-08 16:47:23 +0800200 int err = kern_path_mountpoint(AT_FDCWD, pathname, &path, 0);
Al Viro4e44b682009-04-07 11:08:56 -0400201 if (err)
202 return err;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700203 err = -ENOENT;
Al Viro4e44b682009-04-07 11:08:56 -0400204 while (path.dentry == path.mnt->mnt_root) {
Al Virod8c95842011-12-07 18:16:57 -0500205 if (path.dentry->d_sb->s_magic == AUTOFS_SUPER_MAGIC) {
Al Viro4e44b682009-04-07 11:08:56 -0400206 if (test(&path, data)) {
207 path_get(&path);
Al Viro4e44b682009-04-07 11:08:56 -0400208 *res = path;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700209 err = 0;
Ian Kentac838712013-09-08 16:47:23 +0800210 break;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700211 }
212 }
Al Virobab77eb2009-04-18 03:26:48 -0400213 if (!follow_up(&path))
Al Viro4e44b682009-04-07 11:08:56 -0400214 break;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700215 }
Al Viro4e44b682009-04-07 11:08:56 -0400216 path_put(&path);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700217 return err;
218}
219
Al Viro4e44b682009-04-07 11:08:56 -0400220static int test_by_dev(struct path *path, void *p)
Ian Kent8d7b48e2008-10-15 22:02:54 -0700221{
Al Virod8c95842011-12-07 18:16:57 -0500222 return path->dentry->d_sb->s_dev == *(dev_t *)p;
Al Viro4e44b682009-04-07 11:08:56 -0400223}
Ian Kent8d7b48e2008-10-15 22:02:54 -0700224
Al Viro4e44b682009-04-07 11:08:56 -0400225static int test_by_type(struct path *path, void *p)
226{
227 struct autofs_info *ino = autofs4_dentry_ino(path->dentry);
228 return ino && ino->sbi->type & *(unsigned *)p;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700229}
230
Ian Kent8d7b48e2008-10-15 22:02:54 -0700231/*
232 * Open a file descriptor on the autofs mount point corresponding
233 * to the given path and device number (aka. new_encode_dev(sb->s_dev)).
234 */
Al Viro4e44b682009-04-07 11:08:56 -0400235static int autofs_dev_ioctl_open_mountpoint(const char *name, dev_t devid)
Ian Kent8d7b48e2008-10-15 22:02:54 -0700236{
Ian Kent8d7b48e2008-10-15 22:02:54 -0700237 int err, fd;
238
Al Viroc921b402012-08-12 18:04:37 -0400239 fd = get_unused_fd_flags(O_CLOEXEC);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700240 if (likely(fd >= 0)) {
Al Viro4e44b682009-04-07 11:08:56 -0400241 struct file *filp;
242 struct path path;
243
244 err = find_autofs_mount(name, &path, test_by_dev, &devid);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700245 if (err)
246 goto out;
247
248 /*
Al Viro4e44b682009-04-07 11:08:56 -0400249 * Find autofs super block that has the device number
Ian Kent8d7b48e2008-10-15 22:02:54 -0700250 * corresponding to the autofs fs we want to open.
251 */
Ian Kent8d7b48e2008-10-15 22:02:54 -0700252
Al Viro765927b2012-06-26 21:58:53 +0400253 filp = dentry_open(&path, O_RDONLY, current_cred());
254 path_put(&path);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700255 if (IS_ERR(filp)) {
256 err = PTR_ERR(filp);
257 goto out;
258 }
259
Al Viroc921b402012-08-12 18:04:37 -0400260 fd_install(fd, filp);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700261 }
262
263 return fd;
264
265out:
266 put_unused_fd(fd);
267 return err;
268}
269
270/* Open a file descriptor on an autofs mount point */
271static int autofs_dev_ioctl_openmount(struct file *fp,
272 struct autofs_sb_info *sbi,
273 struct autofs_dev_ioctl *param)
274{
275 const char *path;
276 dev_t devid;
277 int err, fd;
278
279 /* param->path has already been checked */
Ian Kent730c9ee2009-01-06 14:42:06 -0800280 if (!param->openmount.devid)
Ian Kent8d7b48e2008-10-15 22:02:54 -0700281 return -EINVAL;
282
283 param->ioctlfd = -1;
284
285 path = param->path;
Al Viro4e44b682009-04-07 11:08:56 -0400286 devid = new_decode_dev(param->openmount.devid);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700287
288 err = 0;
289 fd = autofs_dev_ioctl_open_mountpoint(path, devid);
290 if (unlikely(fd < 0)) {
291 err = fd;
292 goto out;
293 }
294
295 param->ioctlfd = fd;
296out:
297 return err;
298}
299
300/* Close file descriptor allocated above (user can also use close(2)). */
301static int autofs_dev_ioctl_closemount(struct file *fp,
302 struct autofs_sb_info *sbi,
303 struct autofs_dev_ioctl *param)
304{
305 return sys_close(param->ioctlfd);
306}
307
308/*
309 * Send "ready" status for an existing wait (either a mount or an expire
310 * request).
311 */
312static int autofs_dev_ioctl_ready(struct file *fp,
313 struct autofs_sb_info *sbi,
314 struct autofs_dev_ioctl *param)
315{
316 autofs_wqt_t token;
317
Ian Kent730c9ee2009-01-06 14:42:06 -0800318 token = (autofs_wqt_t) param->ready.token;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700319 return autofs4_wait_release(sbi, token, 0);
320}
321
322/*
323 * Send "fail" status for an existing wait (either a mount or an expire
324 * request).
325 */
326static int autofs_dev_ioctl_fail(struct file *fp,
327 struct autofs_sb_info *sbi,
328 struct autofs_dev_ioctl *param)
329{
330 autofs_wqt_t token;
331 int status;
332
Ian Kent730c9ee2009-01-06 14:42:06 -0800333 token = (autofs_wqt_t) param->fail.token;
334 status = param->fail.status ? param->fail.status : -ENOENT;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700335 return autofs4_wait_release(sbi, token, status);
336}
337
338/*
339 * Set the pipe fd for kernel communication to the daemon.
340 *
341 * Normally this is set at mount using an option but if we
342 * are reconnecting to a busy mount then we need to use this
343 * to tell the autofs mount about the new kernel pipe fd. In
344 * order to protect mounts against incorrectly setting the
345 * pipefd we also require that the autofs mount be catatonic.
346 *
347 * This also sets the process group id used to identify the
348 * controlling process (eg. the owning automount(8) daemon).
349 */
350static int autofs_dev_ioctl_setpipefd(struct file *fp,
351 struct autofs_sb_info *sbi,
352 struct autofs_dev_ioctl *param)
353{
354 int pipefd;
355 int err = 0;
Sukadev Bhattiprolu6eaba352014-01-23 15:54:57 -0800356 struct pid *new_pid = NULL;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700357
Ian Kent730c9ee2009-01-06 14:42:06 -0800358 if (param->setpipefd.pipefd == -1)
Ian Kent8d7b48e2008-10-15 22:02:54 -0700359 return -EINVAL;
360
Ian Kent730c9ee2009-01-06 14:42:06 -0800361 pipefd = param->setpipefd.pipefd;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700362
363 mutex_lock(&sbi->wq_mutex);
364 if (!sbi->catatonic) {
365 mutex_unlock(&sbi->wq_mutex);
366 return -EBUSY;
367 } else {
Sukadev Bhattiprolu6eaba352014-01-23 15:54:57 -0800368 struct file *pipe;
369
370 new_pid = get_task_pid(current, PIDTYPE_PGID);
371
372 if (ns_of_pid(new_pid) != ns_of_pid(sbi->oz_pgrp)) {
373 AUTOFS_WARN("Not allowed to change PID namespace");
374 err = -EINVAL;
375 goto out;
376 }
377
378 pipe = fget(pipefd);
Jesper Juhl3dc8fe42011-03-25 01:51:37 +0800379 if (!pipe) {
380 err = -EBADF;
381 goto out;
382 }
Linus Torvalds64f371b2012-04-29 13:30:08 -0700383 if (autofs_prepare_pipe(pipe) < 0) {
Ian Kent8d7b48e2008-10-15 22:02:54 -0700384 err = -EPIPE;
385 fput(pipe);
386 goto out;
387 }
Sukadev Bhattiprolu6eaba352014-01-23 15:54:57 -0800388 swap(sbi->oz_pgrp, new_pid);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700389 sbi->pipefd = pipefd;
390 sbi->pipe = pipe;
391 sbi->catatonic = 0;
392 }
393out:
Sukadev Bhattiprolu6eaba352014-01-23 15:54:57 -0800394 put_pid(new_pid);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700395 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 */
403static 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 */
412static 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
Ian Kent730c9ee2009-01-06 14:42:06 -0800418 timeout = param->timeout.timeout;
419 param->timeout.timeout = sbi->exp_timeout / HZ;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700420 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 */
432static 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;
Al Viro4e44b682009-04-07 11:08:56 -0400437 struct path path;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700438 dev_t devid;
439 int err = -ENOENT;
440
441 if (param->size <= sizeof(*param)) {
442 err = -EINVAL;
443 goto out;
444 }
445
Al Viro4e44b682009-04-07 11:08:56 -0400446 devid = sbi->sb->s_dev;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700447
Ian Kent730c9ee2009-01-06 14:42:06 -0800448 param->requester.uid = param->requester.gid = -1;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700449
Al Viro4e44b682009-04-07 11:08:56 -0400450 err = find_autofs_mount(param->path, &path, test_by_dev, &devid);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700451 if (err)
452 goto out;
453
Al Viro4e44b682009-04-07 11:08:56 -0400454 ino = autofs4_dentry_ino(path.dentry);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700455 if (ino) {
456 err = 0;
NeilBrown23bfc2a2014-10-13 15:52:14 -0700457 autofs4_expire_wait(path.dentry, 0);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700458 spin_lock(&sbi->fs_lock);
Eric W. Biederman45634cd2012-02-07 16:18:52 -0800459 param->requester.uid = from_kuid_munged(current_user_ns(), ino->uid);
460 param->requester.gid = from_kgid_munged(current_user_ns(), ino->gid);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700461 spin_unlock(&sbi->fs_lock);
462 }
Al Viro4e44b682009-04-07 11:08:56 -0400463 path_put(&path);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700464out:
465 return err;
466}
467
468/*
469 * Call repeatedly until it returns -EAGAIN, meaning there's nothing
470 * more that can be done.
471 */
472static int autofs_dev_ioctl_expire(struct file *fp,
473 struct autofs_sb_info *sbi,
474 struct autofs_dev_ioctl *param)
475{
Ian Kent8d7b48e2008-10-15 22:02:54 -0700476 struct vfsmount *mnt;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700477 int how;
478
Ian Kent730c9ee2009-01-06 14:42:06 -0800479 how = param->expire.how;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700480 mnt = fp->f_path.mnt;
481
Ian Kent56fcef72009-03-31 15:24:43 -0700482 return autofs4_do_expire_multi(sbi->sb, mnt, sbi, how);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700483}
484
485/* Check if autofs mount point is in use */
486static int autofs_dev_ioctl_askumount(struct file *fp,
487 struct autofs_sb_info *sbi,
488 struct autofs_dev_ioctl *param)
489{
Ian Kent730c9ee2009-01-06 14:42:06 -0800490 param->askumount.may_umount = 0;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700491 if (may_umount(fp->f_path.mnt))
Ian Kent730c9ee2009-01-06 14:42:06 -0800492 param->askumount.may_umount = 1;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700493 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
Ian Kentac838712013-09-08 16:47:23 +0800508 * lookup the path and check if it is the root of a mount.
509 * If a type is given we are looking for a particular autofs
510 * mount and if we don't find a match we return fail. If the
511 * located path is the root of a mount we return 1 along with
512 * the super magic of the mount or 0 otherwise.
Ian Kent8d7b48e2008-10-15 22:02:54 -0700513 *
514 * In both cases the the device number (as returned by
515 * new_encode_dev()) is also returned.
516 */
517static int autofs_dev_ioctl_ismountpoint(struct file *fp,
518 struct autofs_sb_info *sbi,
519 struct autofs_dev_ioctl *param)
520{
Al Viro4e44b682009-04-07 11:08:56 -0400521 struct path path;
522 const char *name;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700523 unsigned int type;
Ian Kent730c9ee2009-01-06 14:42:06 -0800524 unsigned int devid, magic;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700525 int err = -ENOENT;
526
527 if (param->size <= sizeof(*param)) {
528 err = -EINVAL;
529 goto out;
530 }
531
Al Viro4e44b682009-04-07 11:08:56 -0400532 name = param->path;
Ian Kent730c9ee2009-01-06 14:42:06 -0800533 type = param->ismountpoint.in.type;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700534
Ian Kent730c9ee2009-01-06 14:42:06 -0800535 param->ismountpoint.out.devid = devid = 0;
536 param->ismountpoint.out.magic = magic = 0;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700537
538 if (!fp || param->ioctlfd == -1) {
Al Viro4e44b682009-04-07 11:08:56 -0400539 if (autofs_type_any(type))
Ian Kentac838712013-09-08 16:47:23 +0800540 err = kern_path_mountpoint(AT_FDCWD,
541 name, &path, LOOKUP_FOLLOW);
Al Viro4e44b682009-04-07 11:08:56 -0400542 else
Ian Kentac838712013-09-08 16:47:23 +0800543 err = find_autofs_mount(name, &path,
544 test_by_type, &type);
Al Viro4e44b682009-04-07 11:08:56 -0400545 if (err)
546 goto out;
Al Virod8c95842011-12-07 18:16:57 -0500547 devid = new_encode_dev(path.dentry->d_sb->s_dev);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700548 err = 0;
Al Virof598f9f2010-01-23 20:08:53 -0500549 if (path.mnt->mnt_root == path.dentry) {
Ian Kent8d7b48e2008-10-15 22:02:54 -0700550 err = 1;
Al Virod8c95842011-12-07 18:16:57 -0500551 magic = path.dentry->d_sb->s_magic;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700552 }
553 } else {
Al Viro4e44b682009-04-07 11:08:56 -0400554 dev_t dev = sbi->sb->s_dev;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700555
Al Viro4e44b682009-04-07 11:08:56 -0400556 err = find_autofs_mount(name, &path, test_by_dev, &dev);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700557 if (err)
558 goto out;
559
Al Viro4e44b682009-04-07 11:08:56 -0400560 devid = new_encode_dev(dev);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700561
Al Viro4e44b682009-04-07 11:08:56 -0400562 err = have_submounts(path.dentry);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700563
David Howellscc53ce52011-01-14 18:45:26 +0000564 if (follow_down_one(&path))
Al Virod8c95842011-12-07 18:16:57 -0500565 magic = path.dentry->d_sb->s_magic;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700566 }
567
Ian Kent730c9ee2009-01-06 14:42:06 -0800568 param->ismountpoint.out.devid = devid;
569 param->ismountpoint.out.magic = magic;
Al Viro4e44b682009-04-07 11:08:56 -0400570 path_put(&path);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700571out:
572 return err;
573}
574
575/*
576 * Our range of ioctl numbers isn't 0 based so we need to shift
577 * the array index by _IOC_NR(AUTOFS_CTL_IOC_FIRST) for the table
578 * lookup.
579 */
580#define cmd_idx(cmd) (cmd - _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST))
581
582static ioctl_fn lookup_dev_ioctl(unsigned int cmd)
583{
584 static struct {
585 int cmd;
586 ioctl_fn fn;
587 } _ioctls[] = {
588 {cmd_idx(AUTOFS_DEV_IOCTL_VERSION_CMD), NULL},
589 {cmd_idx(AUTOFS_DEV_IOCTL_PROTOVER_CMD),
590 autofs_dev_ioctl_protover},
591 {cmd_idx(AUTOFS_DEV_IOCTL_PROTOSUBVER_CMD),
592 autofs_dev_ioctl_protosubver},
593 {cmd_idx(AUTOFS_DEV_IOCTL_OPENMOUNT_CMD),
594 autofs_dev_ioctl_openmount},
595 {cmd_idx(AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD),
596 autofs_dev_ioctl_closemount},
597 {cmd_idx(AUTOFS_DEV_IOCTL_READY_CMD),
598 autofs_dev_ioctl_ready},
599 {cmd_idx(AUTOFS_DEV_IOCTL_FAIL_CMD),
600 autofs_dev_ioctl_fail},
601 {cmd_idx(AUTOFS_DEV_IOCTL_SETPIPEFD_CMD),
602 autofs_dev_ioctl_setpipefd},
603 {cmd_idx(AUTOFS_DEV_IOCTL_CATATONIC_CMD),
604 autofs_dev_ioctl_catatonic},
605 {cmd_idx(AUTOFS_DEV_IOCTL_TIMEOUT_CMD),
606 autofs_dev_ioctl_timeout},
607 {cmd_idx(AUTOFS_DEV_IOCTL_REQUESTER_CMD),
608 autofs_dev_ioctl_requester},
609 {cmd_idx(AUTOFS_DEV_IOCTL_EXPIRE_CMD),
610 autofs_dev_ioctl_expire},
611 {cmd_idx(AUTOFS_DEV_IOCTL_ASKUMOUNT_CMD),
612 autofs_dev_ioctl_askumount},
613 {cmd_idx(AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD),
614 autofs_dev_ioctl_ismountpoint}
615 };
616 unsigned int idx = cmd_idx(cmd);
617
618 return (idx >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[idx].fn;
619}
620
621/* ioctl dispatcher */
622static int _autofs_dev_ioctl(unsigned int command, struct autofs_dev_ioctl __user *user)
623{
624 struct autofs_dev_ioctl *param;
625 struct file *fp;
626 struct autofs_sb_info *sbi;
627 unsigned int cmd_first, cmd;
628 ioctl_fn fn = NULL;
629 int err = 0;
630
631 /* only root can play with this */
632 if (!capable(CAP_SYS_ADMIN))
633 return -EPERM;
634
635 cmd_first = _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST);
636 cmd = _IOC_NR(command);
637
638 if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) ||
639 cmd - cmd_first >= AUTOFS_DEV_IOCTL_IOC_COUNT) {
640 return -ENOTTY;
641 }
642
643 /* Copy the parameters into kernel space. */
644 param = copy_dev_ioctl(user);
645 if (IS_ERR(param))
646 return PTR_ERR(param);
647
648 err = validate_dev_ioctl(command, param);
649 if (err)
650 goto out;
651
652 /* The validate routine above always sets the version */
653 if (cmd == AUTOFS_DEV_IOCTL_VERSION_CMD)
654 goto done;
655
656 fn = lookup_dev_ioctl(cmd);
657 if (!fn) {
658 AUTOFS_WARN("unknown command 0x%08x", command);
659 return -ENOTTY;
660 }
661
662 fp = NULL;
663 sbi = NULL;
664
665 /*
666 * For obvious reasons the openmount can't have a file
667 * descriptor yet. We don't take a reference to the
668 * file during close to allow for immediate release.
669 */
670 if (cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD &&
671 cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) {
672 fp = fget(param->ioctlfd);
673 if (!fp) {
674 if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD)
675 goto cont;
676 err = -EBADF;
677 goto out;
678 }
679
Ian Kent8d7b48e2008-10-15 22:02:54 -0700680 sbi = autofs_dev_ioctl_sbi(fp);
681 if (!sbi || sbi->magic != AUTOFS_SBI_MAGIC) {
682 err = -EINVAL;
683 fput(fp);
684 goto out;
685 }
686
687 /*
688 * Admin needs to be able to set the mount catatonic in
689 * order to be able to perform the re-open.
690 */
691 if (!autofs4_oz_mode(sbi) &&
692 cmd != AUTOFS_DEV_IOCTL_CATATONIC_CMD) {
693 err = -EACCES;
694 fput(fp);
695 goto out;
696 }
697 }
698cont:
699 err = fn(fp, sbi, param);
700
701 if (fp)
702 fput(fp);
703done:
704 if (err >= 0 && copy_to_user(user, param, AUTOFS_DEV_IOCTL_SIZE))
705 err = -EFAULT;
706out:
707 free_dev_ioctl(param);
708 return err;
709}
710
711static long autofs_dev_ioctl(struct file *file, uint command, ulong u)
712{
713 int err;
714 err = _autofs_dev_ioctl(command, (struct autofs_dev_ioctl __user *) u);
715 return (long) err;
716}
717
718#ifdef CONFIG_COMPAT
719static long autofs_dev_ioctl_compat(struct file *file, uint command, ulong u)
720{
721 return (long) autofs_dev_ioctl(file, command, (ulong) compat_ptr(u));
722}
723#else
724#define autofs_dev_ioctl_compat NULL
725#endif
726
727static const struct file_operations _dev_ioctl_fops = {
728 .unlocked_ioctl = autofs_dev_ioctl,
729 .compat_ioctl = autofs_dev_ioctl_compat,
730 .owner = THIS_MODULE,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200731 .llseek = noop_llseek,
Ian Kent8d7b48e2008-10-15 22:02:54 -0700732};
733
734static struct miscdevice _autofs_dev_ioctl_misc = {
Kay Sievers578454f2010-05-20 18:07:20 +0200735 .minor = AUTOFS_MINOR,
Ian Kent8d7b48e2008-10-15 22:02:54 -0700736 .name = AUTOFS_DEVICE_NAME,
737 .fops = &_dev_ioctl_fops
738};
739
Kay Sievers578454f2010-05-20 18:07:20 +0200740MODULE_ALIAS_MISCDEV(AUTOFS_MINOR);
741MODULE_ALIAS("devname:autofs");
742
Ian Kent8d7b48e2008-10-15 22:02:54 -0700743/* Register/deregister misc character device */
Fabian Frederick3ff6db32014-06-04 16:12:21 -0700744int __init autofs_dev_ioctl_init(void)
Ian Kent8d7b48e2008-10-15 22:02:54 -0700745{
746 int r;
747
748 r = misc_register(&_autofs_dev_ioctl_misc);
749 if (r) {
750 AUTOFS_ERROR("misc_register failed for control device");
751 return r;
752 }
753
754 return 0;
755}
756
757void autofs_dev_ioctl_exit(void)
758{
759 misc_deregister(&_autofs_dev_ioctl_misc);
760 return;
761}
762