Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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 |
Ian Kent | bae8ec6 | 2009-01-06 14:42:09 -0800 | [diff] [blame] | 127 | * check that it is terminated and contains at least one "/". |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 128 | */ |
| 129 | static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param) |
| 130 | { |
Ian Kent | 96b0317 | 2008-11-06 12:53:23 -0800 | [diff] [blame] | 131 | int err; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 132 | |
Ian Kent | 96b0317 | 2008-11-06 12:53:23 -0800 | [diff] [blame] | 133 | err = check_dev_ioctl_version(cmd, param); |
| 134 | if (err) { |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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)) { |
Ian Kent | bae8ec6 | 2009-01-06 14:42:09 -0800 | [diff] [blame] | 141 | err = invalid_str(param->path, |
| 142 | (void *) ((size_t) param + param->size)); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 143 | if (err) { |
Ian Kent | bae8ec6 | 2009-01-06 14:42:09 -0800 | [diff] [blame] | 144 | AUTOFS_WARN( |
| 145 | "path string terminator missing for cmd(0x%08x)", |
| 146 | cmd); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 147 | goto out; |
| 148 | } |
| 149 | |
Ian Kent | bae8ec6 | 2009-01-06 14:42:09 -0800 | [diff] [blame] | 150 | err = check_name(param->path); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 151 | if (err) { |
| 152 | AUTOFS_WARN("invalid path supplied for cmd(0x%08x)", |
| 153 | cmd); |
| 154 | goto out; |
| 155 | } |
| 156 | } |
| 157 | |
| 158 | err = 0; |
| 159 | out: |
| 160 | return err; |
| 161 | } |
| 162 | |
| 163 | /* |
| 164 | * Get the autofs super block info struct from the file opened on |
| 165 | * the autofs mount point. |
| 166 | */ |
| 167 | static struct autofs_sb_info *autofs_dev_ioctl_sbi(struct file *f) |
| 168 | { |
| 169 | struct autofs_sb_info *sbi = NULL; |
| 170 | struct inode *inode; |
| 171 | |
| 172 | if (f) { |
| 173 | inode = f->f_path.dentry->d_inode; |
| 174 | sbi = autofs4_sbi(inode->i_sb); |
| 175 | } |
| 176 | return sbi; |
| 177 | } |
| 178 | |
| 179 | /* Return autofs module protocol version */ |
| 180 | static int autofs_dev_ioctl_protover(struct file *fp, |
| 181 | struct autofs_sb_info *sbi, |
| 182 | struct autofs_dev_ioctl *param) |
| 183 | { |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 184 | param->protover.version = sbi->version; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 185 | return 0; |
| 186 | } |
| 187 | |
| 188 | /* Return autofs module protocol sub version */ |
| 189 | static int autofs_dev_ioctl_protosubver(struct file *fp, |
| 190 | struct autofs_sb_info *sbi, |
| 191 | struct autofs_dev_ioctl *param) |
| 192 | { |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 193 | param->protosubver.sub_version = sbi->sub_version; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 194 | return 0; |
| 195 | } |
| 196 | |
| 197 | /* |
| 198 | * Walk down the mount stack looking for an autofs mount that |
| 199 | * has the requested device number (aka. new_encode_dev(sb->s_dev). |
| 200 | */ |
| 201 | static int autofs_dev_ioctl_find_super(struct nameidata *nd, dev_t devno) |
| 202 | { |
| 203 | struct dentry *dentry; |
| 204 | struct inode *inode; |
| 205 | struct super_block *sb; |
| 206 | dev_t s_dev; |
| 207 | unsigned int err; |
| 208 | |
| 209 | err = -ENOENT; |
| 210 | |
| 211 | /* Lookup the dentry name at the base of our mount point */ |
| 212 | dentry = d_lookup(nd->path.dentry, &nd->last); |
| 213 | if (!dentry) |
| 214 | goto out; |
| 215 | |
| 216 | dput(nd->path.dentry); |
| 217 | nd->path.dentry = dentry; |
| 218 | |
| 219 | /* And follow the mount stack looking for our autofs mount */ |
| 220 | while (follow_down(&nd->path.mnt, &nd->path.dentry)) { |
| 221 | inode = nd->path.dentry->d_inode; |
| 222 | if (!inode) |
| 223 | break; |
| 224 | |
| 225 | sb = inode->i_sb; |
| 226 | s_dev = new_encode_dev(sb->s_dev); |
| 227 | if (devno == s_dev) { |
| 228 | if (sb->s_magic == AUTOFS_SUPER_MAGIC) { |
| 229 | err = 0; |
| 230 | break; |
| 231 | } |
| 232 | } |
| 233 | } |
| 234 | out: |
| 235 | return err; |
| 236 | } |
| 237 | |
| 238 | /* |
| 239 | * Walk down the mount stack looking for an autofs mount that |
| 240 | * has the requested mount type (ie. indirect, direct or offset). |
| 241 | */ |
| 242 | static int autofs_dev_ioctl_find_sbi_type(struct nameidata *nd, unsigned int type) |
| 243 | { |
| 244 | struct dentry *dentry; |
| 245 | struct autofs_info *ino; |
| 246 | unsigned int err; |
| 247 | |
| 248 | err = -ENOENT; |
| 249 | |
| 250 | /* Lookup the dentry name at the base of our mount point */ |
| 251 | dentry = d_lookup(nd->path.dentry, &nd->last); |
| 252 | if (!dentry) |
| 253 | goto out; |
| 254 | |
| 255 | dput(nd->path.dentry); |
| 256 | nd->path.dentry = dentry; |
| 257 | |
| 258 | /* And follow the mount stack looking for our autofs mount */ |
| 259 | while (follow_down(&nd->path.mnt, &nd->path.dentry)) { |
| 260 | ino = autofs4_dentry_ino(nd->path.dentry); |
| 261 | if (ino && ino->sbi->type & type) { |
| 262 | err = 0; |
| 263 | break; |
| 264 | } |
| 265 | } |
| 266 | out: |
| 267 | return err; |
| 268 | } |
| 269 | |
| 270 | static void autofs_dev_ioctl_fd_install(unsigned int fd, struct file *file) |
| 271 | { |
| 272 | struct files_struct *files = current->files; |
| 273 | struct fdtable *fdt; |
| 274 | |
| 275 | spin_lock(&files->file_lock); |
| 276 | fdt = files_fdtable(files); |
| 277 | BUG_ON(fdt->fd[fd] != NULL); |
| 278 | rcu_assign_pointer(fdt->fd[fd], file); |
| 279 | FD_SET(fd, fdt->close_on_exec); |
| 280 | spin_unlock(&files->file_lock); |
| 281 | } |
| 282 | |
| 283 | |
| 284 | /* |
| 285 | * Open a file descriptor on the autofs mount point corresponding |
| 286 | * to the given path and device number (aka. new_encode_dev(sb->s_dev)). |
| 287 | */ |
| 288 | static int autofs_dev_ioctl_open_mountpoint(const char *path, dev_t devid) |
| 289 | { |
| 290 | struct file *filp; |
| 291 | struct nameidata nd; |
| 292 | int err, fd; |
| 293 | |
| 294 | fd = get_unused_fd(); |
| 295 | if (likely(fd >= 0)) { |
| 296 | /* Get nameidata of the parent directory */ |
| 297 | err = path_lookup(path, LOOKUP_PARENT, &nd); |
| 298 | if (err) |
| 299 | goto out; |
| 300 | |
| 301 | /* |
| 302 | * Search down, within the parent, looking for an |
| 303 | * autofs super block that has the device number |
| 304 | * corresponding to the autofs fs we want to open. |
| 305 | */ |
| 306 | err = autofs_dev_ioctl_find_super(&nd, devid); |
| 307 | if (err) { |
| 308 | path_put(&nd.path); |
| 309 | goto out; |
| 310 | } |
| 311 | |
David Howells | 745ca24 | 2008-11-14 10:39:22 +1100 | [diff] [blame] | 312 | filp = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY, |
| 313 | current_cred()); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 314 | if (IS_ERR(filp)) { |
| 315 | err = PTR_ERR(filp); |
| 316 | goto out; |
| 317 | } |
| 318 | |
| 319 | autofs_dev_ioctl_fd_install(fd, filp); |
| 320 | } |
| 321 | |
| 322 | return fd; |
| 323 | |
| 324 | out: |
| 325 | put_unused_fd(fd); |
| 326 | return err; |
| 327 | } |
| 328 | |
| 329 | /* Open a file descriptor on an autofs mount point */ |
| 330 | static int autofs_dev_ioctl_openmount(struct file *fp, |
| 331 | struct autofs_sb_info *sbi, |
| 332 | struct autofs_dev_ioctl *param) |
| 333 | { |
| 334 | const char *path; |
| 335 | dev_t devid; |
| 336 | int err, fd; |
| 337 | |
| 338 | /* param->path has already been checked */ |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 339 | if (!param->openmount.devid) |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 340 | return -EINVAL; |
| 341 | |
| 342 | param->ioctlfd = -1; |
| 343 | |
| 344 | path = param->path; |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 345 | devid = param->openmount.devid; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 346 | |
| 347 | err = 0; |
| 348 | fd = autofs_dev_ioctl_open_mountpoint(path, devid); |
| 349 | if (unlikely(fd < 0)) { |
| 350 | err = fd; |
| 351 | goto out; |
| 352 | } |
| 353 | |
| 354 | param->ioctlfd = fd; |
| 355 | out: |
| 356 | return err; |
| 357 | } |
| 358 | |
| 359 | /* Close file descriptor allocated above (user can also use close(2)). */ |
| 360 | static int autofs_dev_ioctl_closemount(struct file *fp, |
| 361 | struct autofs_sb_info *sbi, |
| 362 | struct autofs_dev_ioctl *param) |
| 363 | { |
| 364 | return sys_close(param->ioctlfd); |
| 365 | } |
| 366 | |
| 367 | /* |
| 368 | * Send "ready" status for an existing wait (either a mount or an expire |
| 369 | * request). |
| 370 | */ |
| 371 | static int autofs_dev_ioctl_ready(struct file *fp, |
| 372 | struct autofs_sb_info *sbi, |
| 373 | struct autofs_dev_ioctl *param) |
| 374 | { |
| 375 | autofs_wqt_t token; |
| 376 | |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 377 | token = (autofs_wqt_t) param->ready.token; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 378 | return autofs4_wait_release(sbi, token, 0); |
| 379 | } |
| 380 | |
| 381 | /* |
| 382 | * Send "fail" status for an existing wait (either a mount or an expire |
| 383 | * request). |
| 384 | */ |
| 385 | static int autofs_dev_ioctl_fail(struct file *fp, |
| 386 | struct autofs_sb_info *sbi, |
| 387 | struct autofs_dev_ioctl *param) |
| 388 | { |
| 389 | autofs_wqt_t token; |
| 390 | int status; |
| 391 | |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 392 | token = (autofs_wqt_t) param->fail.token; |
| 393 | status = param->fail.status ? param->fail.status : -ENOENT; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 394 | return autofs4_wait_release(sbi, token, status); |
| 395 | } |
| 396 | |
| 397 | /* |
| 398 | * Set the pipe fd for kernel communication to the daemon. |
| 399 | * |
| 400 | * Normally this is set at mount using an option but if we |
| 401 | * are reconnecting to a busy mount then we need to use this |
| 402 | * to tell the autofs mount about the new kernel pipe fd. In |
| 403 | * order to protect mounts against incorrectly setting the |
| 404 | * pipefd we also require that the autofs mount be catatonic. |
| 405 | * |
| 406 | * This also sets the process group id used to identify the |
| 407 | * controlling process (eg. the owning automount(8) daemon). |
| 408 | */ |
| 409 | static int autofs_dev_ioctl_setpipefd(struct file *fp, |
| 410 | struct autofs_sb_info *sbi, |
| 411 | struct autofs_dev_ioctl *param) |
| 412 | { |
| 413 | int pipefd; |
| 414 | int err = 0; |
| 415 | |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 416 | if (param->setpipefd.pipefd == -1) |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 417 | return -EINVAL; |
| 418 | |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 419 | pipefd = param->setpipefd.pipefd; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 420 | |
| 421 | mutex_lock(&sbi->wq_mutex); |
| 422 | if (!sbi->catatonic) { |
| 423 | mutex_unlock(&sbi->wq_mutex); |
| 424 | return -EBUSY; |
| 425 | } else { |
| 426 | struct file *pipe = fget(pipefd); |
| 427 | if (!pipe->f_op || !pipe->f_op->write) { |
| 428 | err = -EPIPE; |
| 429 | fput(pipe); |
| 430 | goto out; |
| 431 | } |
| 432 | sbi->oz_pgrp = task_pgrp_nr(current); |
| 433 | sbi->pipefd = pipefd; |
| 434 | sbi->pipe = pipe; |
| 435 | sbi->catatonic = 0; |
| 436 | } |
| 437 | out: |
| 438 | mutex_unlock(&sbi->wq_mutex); |
| 439 | return err; |
| 440 | } |
| 441 | |
| 442 | /* |
| 443 | * Make the autofs mount point catatonic, no longer responsive to |
| 444 | * mount requests. Also closes the kernel pipe file descriptor. |
| 445 | */ |
| 446 | static int autofs_dev_ioctl_catatonic(struct file *fp, |
| 447 | struct autofs_sb_info *sbi, |
| 448 | struct autofs_dev_ioctl *param) |
| 449 | { |
| 450 | autofs4_catatonic_mode(sbi); |
| 451 | return 0; |
| 452 | } |
| 453 | |
| 454 | /* Set the autofs mount timeout */ |
| 455 | static int autofs_dev_ioctl_timeout(struct file *fp, |
| 456 | struct autofs_sb_info *sbi, |
| 457 | struct autofs_dev_ioctl *param) |
| 458 | { |
| 459 | unsigned long timeout; |
| 460 | |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 461 | timeout = param->timeout.timeout; |
| 462 | param->timeout.timeout = sbi->exp_timeout / HZ; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 463 | sbi->exp_timeout = timeout * HZ; |
| 464 | return 0; |
| 465 | } |
| 466 | |
| 467 | /* |
| 468 | * Return the uid and gid of the last request for the mount |
| 469 | * |
| 470 | * When reconstructing an autofs mount tree with active mounts |
| 471 | * we need to re-connect to mounts that may have used the original |
| 472 | * process uid and gid (or string variations of them) for mount |
| 473 | * lookups within the map entry. |
| 474 | */ |
| 475 | static int autofs_dev_ioctl_requester(struct file *fp, |
| 476 | struct autofs_sb_info *sbi, |
| 477 | struct autofs_dev_ioctl *param) |
| 478 | { |
| 479 | struct autofs_info *ino; |
| 480 | struct nameidata nd; |
| 481 | const char *path; |
| 482 | dev_t devid; |
| 483 | int err = -ENOENT; |
| 484 | |
| 485 | if (param->size <= sizeof(*param)) { |
| 486 | err = -EINVAL; |
| 487 | goto out; |
| 488 | } |
| 489 | |
| 490 | path = param->path; |
| 491 | devid = sbi->sb->s_dev; |
| 492 | |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 493 | param->requester.uid = param->requester.gid = -1; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 494 | |
| 495 | /* Get nameidata of the parent directory */ |
| 496 | err = path_lookup(path, LOOKUP_PARENT, &nd); |
| 497 | if (err) |
| 498 | goto out; |
| 499 | |
| 500 | err = autofs_dev_ioctl_find_super(&nd, devid); |
| 501 | if (err) |
| 502 | goto out_release; |
| 503 | |
| 504 | ino = autofs4_dentry_ino(nd.path.dentry); |
| 505 | if (ino) { |
| 506 | err = 0; |
| 507 | autofs4_expire_wait(nd.path.dentry); |
| 508 | spin_lock(&sbi->fs_lock); |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 509 | param->requester.uid = ino->uid; |
| 510 | param->requester.gid = ino->gid; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 511 | spin_unlock(&sbi->fs_lock); |
| 512 | } |
| 513 | |
| 514 | out_release: |
| 515 | path_put(&nd.path); |
| 516 | out: |
| 517 | return err; |
| 518 | } |
| 519 | |
| 520 | /* |
| 521 | * Call repeatedly until it returns -EAGAIN, meaning there's nothing |
| 522 | * more that can be done. |
| 523 | */ |
| 524 | static int autofs_dev_ioctl_expire(struct file *fp, |
| 525 | struct autofs_sb_info *sbi, |
| 526 | struct autofs_dev_ioctl *param) |
| 527 | { |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 528 | struct vfsmount *mnt; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 529 | int how; |
| 530 | |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 531 | how = param->expire.how; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 532 | mnt = fp->f_path.mnt; |
| 533 | |
Ian Kent | 56fcef7 | 2009-03-31 15:24:43 -0700 | [diff] [blame^] | 534 | return autofs4_do_expire_multi(sbi->sb, mnt, sbi, how); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 535 | } |
| 536 | |
| 537 | /* Check if autofs mount point is in use */ |
| 538 | static int autofs_dev_ioctl_askumount(struct file *fp, |
| 539 | struct autofs_sb_info *sbi, |
| 540 | struct autofs_dev_ioctl *param) |
| 541 | { |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 542 | param->askumount.may_umount = 0; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 543 | if (may_umount(fp->f_path.mnt)) |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 544 | param->askumount.may_umount = 1; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 545 | return 0; |
| 546 | } |
| 547 | |
| 548 | /* |
| 549 | * Check if the given path is a mountpoint. |
| 550 | * |
| 551 | * If we are supplied with the file descriptor of an autofs |
| 552 | * mount we're looking for a specific mount. In this case |
| 553 | * the path is considered a mountpoint if it is itself a |
| 554 | * mountpoint or contains a mount, such as a multi-mount |
| 555 | * without a root mount. In this case we return 1 if the |
| 556 | * path is a mount point and the super magic of the covering |
| 557 | * mount if there is one or 0 if it isn't a mountpoint. |
| 558 | * |
| 559 | * If we aren't supplied with a file descriptor then we |
| 560 | * lookup the nameidata of the path and check if it is the |
| 561 | * root of a mount. If a type is given we are looking for |
| 562 | * a particular autofs mount and if we don't find a match |
| 563 | * we return fail. If the located nameidata path is the |
| 564 | * root of a mount we return 1 along with the super magic |
| 565 | * of the mount or 0 otherwise. |
| 566 | * |
| 567 | * In both cases the the device number (as returned by |
| 568 | * new_encode_dev()) is also returned. |
| 569 | */ |
| 570 | static int autofs_dev_ioctl_ismountpoint(struct file *fp, |
| 571 | struct autofs_sb_info *sbi, |
| 572 | struct autofs_dev_ioctl *param) |
| 573 | { |
| 574 | struct nameidata nd; |
| 575 | const char *path; |
| 576 | unsigned int type; |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 577 | unsigned int devid, magic; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 578 | int err = -ENOENT; |
| 579 | |
| 580 | if (param->size <= sizeof(*param)) { |
| 581 | err = -EINVAL; |
| 582 | goto out; |
| 583 | } |
| 584 | |
| 585 | path = param->path; |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 586 | type = param->ismountpoint.in.type; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 587 | |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 588 | param->ismountpoint.out.devid = devid = 0; |
| 589 | param->ismountpoint.out.magic = magic = 0; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 590 | |
| 591 | if (!fp || param->ioctlfd == -1) { |
Ian Kent | a92daf6 | 2009-01-06 14:42:08 -0800 | [diff] [blame] | 592 | if (autofs_type_any(type)) { |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 593 | struct super_block *sb; |
| 594 | |
| 595 | err = path_lookup(path, LOOKUP_FOLLOW, &nd); |
| 596 | if (err) |
| 597 | goto out; |
| 598 | |
| 599 | sb = nd.path.dentry->d_sb; |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 600 | devid = new_encode_dev(sb->s_dev); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 601 | } else { |
| 602 | struct autofs_info *ino; |
| 603 | |
| 604 | err = path_lookup(path, LOOKUP_PARENT, &nd); |
| 605 | if (err) |
| 606 | goto out; |
| 607 | |
| 608 | err = autofs_dev_ioctl_find_sbi_type(&nd, type); |
| 609 | if (err) |
| 610 | goto out_release; |
| 611 | |
| 612 | ino = autofs4_dentry_ino(nd.path.dentry); |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 613 | devid = autofs4_get_dev(ino->sbi); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 614 | } |
| 615 | |
| 616 | err = 0; |
| 617 | if (nd.path.dentry->d_inode && |
| 618 | nd.path.mnt->mnt_root == nd.path.dentry) { |
| 619 | err = 1; |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 620 | magic = nd.path.dentry->d_inode->i_sb->s_magic; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 621 | } |
| 622 | } else { |
Ian Kent | 41cfef2 | 2009-01-06 14:42:07 -0800 | [diff] [blame] | 623 | dev_t dev = autofs4_get_dev(sbi); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 624 | |
| 625 | err = path_lookup(path, LOOKUP_PARENT, &nd); |
| 626 | if (err) |
| 627 | goto out; |
| 628 | |
Ian Kent | 41cfef2 | 2009-01-06 14:42:07 -0800 | [diff] [blame] | 629 | err = autofs_dev_ioctl_find_super(&nd, dev); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 630 | if (err) |
| 631 | goto out_release; |
| 632 | |
Ian Kent | 41cfef2 | 2009-01-06 14:42:07 -0800 | [diff] [blame] | 633 | devid = dev; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 634 | |
| 635 | err = have_submounts(nd.path.dentry); |
| 636 | |
| 637 | if (nd.path.mnt->mnt_mountpoint != nd.path.mnt->mnt_root) { |
| 638 | if (follow_down(&nd.path.mnt, &nd.path.dentry)) { |
| 639 | struct inode *inode = nd.path.dentry->d_inode; |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 640 | magic = inode->i_sb->s_magic; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 641 | } |
| 642 | } |
| 643 | } |
| 644 | |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 645 | param->ismountpoint.out.devid = devid; |
| 646 | param->ismountpoint.out.magic = magic; |
| 647 | |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 648 | out_release: |
| 649 | path_put(&nd.path); |
| 650 | out: |
| 651 | return err; |
| 652 | } |
| 653 | |
| 654 | /* |
| 655 | * Our range of ioctl numbers isn't 0 based so we need to shift |
| 656 | * the array index by _IOC_NR(AUTOFS_CTL_IOC_FIRST) for the table |
| 657 | * lookup. |
| 658 | */ |
| 659 | #define cmd_idx(cmd) (cmd - _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST)) |
| 660 | |
| 661 | static ioctl_fn lookup_dev_ioctl(unsigned int cmd) |
| 662 | { |
| 663 | static struct { |
| 664 | int cmd; |
| 665 | ioctl_fn fn; |
| 666 | } _ioctls[] = { |
| 667 | {cmd_idx(AUTOFS_DEV_IOCTL_VERSION_CMD), NULL}, |
| 668 | {cmd_idx(AUTOFS_DEV_IOCTL_PROTOVER_CMD), |
| 669 | autofs_dev_ioctl_protover}, |
| 670 | {cmd_idx(AUTOFS_DEV_IOCTL_PROTOSUBVER_CMD), |
| 671 | autofs_dev_ioctl_protosubver}, |
| 672 | {cmd_idx(AUTOFS_DEV_IOCTL_OPENMOUNT_CMD), |
| 673 | autofs_dev_ioctl_openmount}, |
| 674 | {cmd_idx(AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD), |
| 675 | autofs_dev_ioctl_closemount}, |
| 676 | {cmd_idx(AUTOFS_DEV_IOCTL_READY_CMD), |
| 677 | autofs_dev_ioctl_ready}, |
| 678 | {cmd_idx(AUTOFS_DEV_IOCTL_FAIL_CMD), |
| 679 | autofs_dev_ioctl_fail}, |
| 680 | {cmd_idx(AUTOFS_DEV_IOCTL_SETPIPEFD_CMD), |
| 681 | autofs_dev_ioctl_setpipefd}, |
| 682 | {cmd_idx(AUTOFS_DEV_IOCTL_CATATONIC_CMD), |
| 683 | autofs_dev_ioctl_catatonic}, |
| 684 | {cmd_idx(AUTOFS_DEV_IOCTL_TIMEOUT_CMD), |
| 685 | autofs_dev_ioctl_timeout}, |
| 686 | {cmd_idx(AUTOFS_DEV_IOCTL_REQUESTER_CMD), |
| 687 | autofs_dev_ioctl_requester}, |
| 688 | {cmd_idx(AUTOFS_DEV_IOCTL_EXPIRE_CMD), |
| 689 | autofs_dev_ioctl_expire}, |
| 690 | {cmd_idx(AUTOFS_DEV_IOCTL_ASKUMOUNT_CMD), |
| 691 | autofs_dev_ioctl_askumount}, |
| 692 | {cmd_idx(AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD), |
| 693 | autofs_dev_ioctl_ismountpoint} |
| 694 | }; |
| 695 | unsigned int idx = cmd_idx(cmd); |
| 696 | |
| 697 | return (idx >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[idx].fn; |
| 698 | } |
| 699 | |
| 700 | /* ioctl dispatcher */ |
| 701 | static int _autofs_dev_ioctl(unsigned int command, struct autofs_dev_ioctl __user *user) |
| 702 | { |
| 703 | struct autofs_dev_ioctl *param; |
| 704 | struct file *fp; |
| 705 | struct autofs_sb_info *sbi; |
| 706 | unsigned int cmd_first, cmd; |
| 707 | ioctl_fn fn = NULL; |
| 708 | int err = 0; |
| 709 | |
| 710 | /* only root can play with this */ |
| 711 | if (!capable(CAP_SYS_ADMIN)) |
| 712 | return -EPERM; |
| 713 | |
| 714 | cmd_first = _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST); |
| 715 | cmd = _IOC_NR(command); |
| 716 | |
| 717 | if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) || |
| 718 | cmd - cmd_first >= AUTOFS_DEV_IOCTL_IOC_COUNT) { |
| 719 | return -ENOTTY; |
| 720 | } |
| 721 | |
| 722 | /* Copy the parameters into kernel space. */ |
| 723 | param = copy_dev_ioctl(user); |
| 724 | if (IS_ERR(param)) |
| 725 | return PTR_ERR(param); |
| 726 | |
| 727 | err = validate_dev_ioctl(command, param); |
| 728 | if (err) |
| 729 | goto out; |
| 730 | |
| 731 | /* The validate routine above always sets the version */ |
| 732 | if (cmd == AUTOFS_DEV_IOCTL_VERSION_CMD) |
| 733 | goto done; |
| 734 | |
| 735 | fn = lookup_dev_ioctl(cmd); |
| 736 | if (!fn) { |
| 737 | AUTOFS_WARN("unknown command 0x%08x", command); |
| 738 | return -ENOTTY; |
| 739 | } |
| 740 | |
| 741 | fp = NULL; |
| 742 | sbi = NULL; |
| 743 | |
| 744 | /* |
| 745 | * For obvious reasons the openmount can't have a file |
| 746 | * descriptor yet. We don't take a reference to the |
| 747 | * file during close to allow for immediate release. |
| 748 | */ |
| 749 | if (cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD && |
| 750 | cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) { |
| 751 | fp = fget(param->ioctlfd); |
| 752 | if (!fp) { |
| 753 | if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) |
| 754 | goto cont; |
| 755 | err = -EBADF; |
| 756 | goto out; |
| 757 | } |
| 758 | |
| 759 | if (!fp->f_op) { |
| 760 | err = -ENOTTY; |
| 761 | fput(fp); |
| 762 | goto out; |
| 763 | } |
| 764 | |
| 765 | sbi = autofs_dev_ioctl_sbi(fp); |
| 766 | if (!sbi || sbi->magic != AUTOFS_SBI_MAGIC) { |
| 767 | err = -EINVAL; |
| 768 | fput(fp); |
| 769 | goto out; |
| 770 | } |
| 771 | |
| 772 | /* |
| 773 | * Admin needs to be able to set the mount catatonic in |
| 774 | * order to be able to perform the re-open. |
| 775 | */ |
| 776 | if (!autofs4_oz_mode(sbi) && |
| 777 | cmd != AUTOFS_DEV_IOCTL_CATATONIC_CMD) { |
| 778 | err = -EACCES; |
| 779 | fput(fp); |
| 780 | goto out; |
| 781 | } |
| 782 | } |
| 783 | cont: |
| 784 | err = fn(fp, sbi, param); |
| 785 | |
| 786 | if (fp) |
| 787 | fput(fp); |
| 788 | done: |
| 789 | if (err >= 0 && copy_to_user(user, param, AUTOFS_DEV_IOCTL_SIZE)) |
| 790 | err = -EFAULT; |
| 791 | out: |
| 792 | free_dev_ioctl(param); |
| 793 | return err; |
| 794 | } |
| 795 | |
| 796 | static long autofs_dev_ioctl(struct file *file, uint command, ulong u) |
| 797 | { |
| 798 | int err; |
| 799 | err = _autofs_dev_ioctl(command, (struct autofs_dev_ioctl __user *) u); |
| 800 | return (long) err; |
| 801 | } |
| 802 | |
| 803 | #ifdef CONFIG_COMPAT |
| 804 | static long autofs_dev_ioctl_compat(struct file *file, uint command, ulong u) |
| 805 | { |
| 806 | return (long) autofs_dev_ioctl(file, command, (ulong) compat_ptr(u)); |
| 807 | } |
| 808 | #else |
| 809 | #define autofs_dev_ioctl_compat NULL |
| 810 | #endif |
| 811 | |
| 812 | static const struct file_operations _dev_ioctl_fops = { |
| 813 | .unlocked_ioctl = autofs_dev_ioctl, |
| 814 | .compat_ioctl = autofs_dev_ioctl_compat, |
| 815 | .owner = THIS_MODULE, |
| 816 | }; |
| 817 | |
| 818 | static struct miscdevice _autofs_dev_ioctl_misc = { |
| 819 | .minor = MISC_DYNAMIC_MINOR, |
| 820 | .name = AUTOFS_DEVICE_NAME, |
| 821 | .fops = &_dev_ioctl_fops |
| 822 | }; |
| 823 | |
| 824 | /* Register/deregister misc character device */ |
| 825 | int autofs_dev_ioctl_init(void) |
| 826 | { |
| 827 | int r; |
| 828 | |
| 829 | r = misc_register(&_autofs_dev_ioctl_misc); |
| 830 | if (r) { |
| 831 | AUTOFS_ERROR("misc_register failed for control device"); |
| 832 | return r; |
| 833 | } |
| 834 | |
| 835 | return 0; |
| 836 | } |
| 837 | |
| 838 | void autofs_dev_ioctl_exit(void) |
| 839 | { |
| 840 | misc_deregister(&_autofs_dev_ioctl_misc); |
| 841 | return; |
| 842 | } |
| 843 | |