fs/autofs4/dev-ioctl.c

   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/cred.h>
  21 #include <linux/compat.h>
  22 #include <linux/syscalls.h>
  23 #include <linux/magic.h>
  24 #include <linux/dcache.h>
  25 #include <linux/uaccess.h>
  26 #include <linux/slab.h>
  27
  28 #include "autofs_i.h"
  29
  30 /*
  31  * This module implements an interface for routing autofs ioctl control
  32  * commands via a miscellaneous device file.
  33  *
  34  * The alternate interface is needed because we need to be able open
  35  * an ioctl file descriptor on an autofs mount that may be covered by
  36  * another mount. This situation arises when starting automount(8)
  37  * or other user space daemon which uses direct mounts or offset
  38  * mounts (used for autofs lazy mount/umount of nested mount trees),
  39  * which have been left busy at at service shutdown.
  40  */
  41
  42 typedef int (*ioctl_fn)(struct file *, struct autofs_sb_info *,
  43                         struct autofs_dev_ioctl *);
  44
  45 static int check_name(const char *name)
  46 {
  47         if (!strchr(name, '/'))
  48                 return -EINVAL;
  49         return 0;
  50 }
  51
  52 /*
  53  * Check a string doesn't overrun the chunk of
  54  * memory we copied from user land.
  55  */
  56 static int invalid_str(char *str, size_t size)
  57 {
  58         if (memchr(str, 0, size))
  59                 return 0;
  60         return -EINVAL;
  61 }
  62
  63 /*
  64  * Check that the user compiled against correct version of autofs
  65  * misc device code.
  66  *
  67  * As well as checking the version compatibility this always copies
  68  * the kernel interface version out.
  69  */
  70 static int check_dev_ioctl_version(int cmd, struct autofs_dev_ioctl *param)
  71 {
  72         int err = 0;
  73
  74         if ((param->ver_major != AUTOFS_DEV_IOCTL_VERSION_MAJOR) ||
  75             (param->ver_minor > AUTOFS_DEV_IOCTL_VERSION_MINOR)) {
  76                 pr_warn("ioctl control interface version mismatch: "
  77                         "kernel(%u.%u), user(%u.%u), cmd(0x%08x)\n",
  78                         AUTOFS_DEV_IOCTL_VERSION_MAJOR,
  79                         AUTOFS_DEV_IOCTL_VERSION_MINOR,
  80                         param->ver_major, param->ver_minor, cmd);
  81                 err = -EINVAL;
  82         }
  83
  84         /* Fill in the kernel version. */
  85         param->ver_major = AUTOFS_DEV_IOCTL_VERSION_MAJOR;
  86         param->ver_minor = AUTOFS_DEV_IOCTL_VERSION_MINOR;
  87
  88         return err;
  89 }
  90
  91 /*
  92  * Copy parameter control struct, including a possible path allocated
  93  * at the end of the struct.
  94  */
  95 static struct autofs_dev_ioctl *
  96 copy_dev_ioctl(struct autofs_dev_ioctl __user *in)
  97 {
  98         struct autofs_dev_ioctl tmp, *res;
  99
 100         if (copy_from_user(&tmp, in, AUTOFS_DEV_IOCTL_SIZE))
 101                 return ERR_PTR(-EFAULT);
 102
 103         if (tmp.size < AUTOFS_DEV_IOCTL_SIZE)
 104                 return ERR_PTR(-EINVAL);
 105
 106         if (tmp.size > AUTOFS_DEV_IOCTL_SIZE + PATH_MAX)
 107                 return ERR_PTR(-ENAMETOOLONG);
 108
 109         res = memdup_user(in, tmp.size);
 110         if (!IS_ERR(res))
 111                 res->size = tmp.size;
 112
 113         return res;
 114 }
 115
 116 static inline void free_dev_ioctl(struct autofs_dev_ioctl *param)
 117 {
 118         kfree(param);
 119 }
 120
 121 /*
 122  * Check sanity of parameter control fields and if a path is present
 123  * check that it is terminated and contains at least one "/".
 124  */
 125 static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param)
 126 {
 127         int err;
 128
 129         err = check_dev_ioctl_version(cmd, param);
 130         if (err) {
 131                 pr_warn("invalid device control module version "
 132                         "supplied for cmd(0x%08x)\n", cmd);
 133                 goto out;
 134         }
 135
 136         if (param->size > AUTOFS_DEV_IOCTL_SIZE) {
 137                 err = invalid_str(param->path, param->size - AUTOFS_DEV_IOCTL_SIZE);
 138                 if (err) {
 139                         pr_warn(
 140                           "path string terminator missing for cmd(0x%08x)\n",
 141                           cmd);
 142                         goto out;
 143                 }
 144
 145                 err = check_name(param->path);
 146                 if (err) {
 147                         pr_warn("invalid path supplied for cmd(0x%08x)\n",
 148                                 cmd);
 149                         goto out;
 150                 }
 151         }
 152
 153         err = 0;
 154 out:
 155         return err;
 156 }
 157
 158 /*
 159  * Get the autofs super block info struct from the file opened on
 160  * the autofs mount point.
 161  */
 162 static struct autofs_sb_info *autofs_dev_ioctl_sbi(struct file *f)
 163 {
 164         struct autofs_sb_info *sbi = NULL;
 165         struct inode *inode;
 166
 167         if (f) {
 168                 inode = file_inode(f);
 169                 sbi = autofs4_sbi(inode->i_sb);
 170         }
 171         return sbi;
 172 }
 173
 174 /* Return autofs dev ioctl version */
 175 static int autofs_dev_ioctl_version(struct file *fp,
 176                                     struct autofs_sb_info *sbi,
 177                                     struct autofs_dev_ioctl *param)
 178 {
 179         /* This should have already been set. */
 180         param->ver_major = AUTOFS_DEV_IOCTL_VERSION_MAJOR;
 181         param->ver_minor = AUTOFS_DEV_IOCTL_VERSION_MINOR;
 182         return 0;
 183 }
 184
 185 /* Return autofs module protocol version */
 186 static int autofs_dev_ioctl_protover(struct file *fp,
 187                                      struct autofs_sb_info *sbi,
 188                                      struct autofs_dev_ioctl *param)
 189 {
 190         param->protover.version = sbi->version;
 191         return 0;
 192 }
 193
 194 /* Return autofs module protocol sub version */
 195 static int autofs_dev_ioctl_protosubver(struct file *fp,
 196                                         struct autofs_sb_info *sbi,
 197                                         struct autofs_dev_ioctl *param)
 198 {
 199         param->protosubver.sub_version = sbi->sub_version;
 200         return 0;
 201 }
 202
 203 /* Find the topmost mount satisfying test() */
 204 static int find_autofs_mount(const char *pathname,
 205                              struct path *res,
 206                              int test(const struct path *path, void *data),
 207                              void *data)
 208 {
 209         struct path path;
 210         int err;
 211
 212         err = kern_path_mountpoint(AT_FDCWD, pathname, &path, 0);
 213         if (err)
 214                 return err;
 215         err = -ENOENT;
 216         while (path.dentry == path.mnt->mnt_root) {
 217                 if (path.dentry->d_sb->s_magic == AUTOFS_SUPER_MAGIC) {
 218                         if (test(&path, data)) {
 219                                 path_get(&path);
 220                                 *res = path;
 221                                 err = 0;
 222                                 break;
 223                         }
 224                 }
 225                 if (!follow_up(&path))
 226                         break;
 227         }
 228         path_put(&path);
 229         return err;
 230 }
 231
 232 static int test_by_dev(const struct path *path, void *p)
 233 {
 234         return path->dentry->d_sb->s_dev == *(dev_t *)p;
 235 }
 236
 237 static int test_by_type(const struct path *path, void *p)
 238 {
 239         struct autofs_info *ino = autofs4_dentry_ino(path->dentry);
 240
 241         return ino && ino->sbi->type & *(unsigned *)p;
 242 }
 243
 244 /*
 245  * Open a file descriptor on the autofs mount point corresponding
 246  * to the given path and device number (aka. new_encode_dev(sb->s_dev)).
 247  */
 248 static int autofs_dev_ioctl_open_mountpoint(const char *name, dev_t devid)
 249 {
 250         int err, fd;
 251
 252         fd = get_unused_fd_flags(O_CLOEXEC);
 253         if (likely(fd >= 0)) {
 254                 struct file *filp;
 255                 struct path path;
 256
 257                 err = find_autofs_mount(name, &path, test_by_dev, &devid);
 258                 if (err)
 259                         goto out;
 260
 261                 filp = dentry_open(&path, O_RDONLY, current_cred());
 262                 path_put(&path);
 263                 if (IS_ERR(filp)) {
 264                         err = PTR_ERR(filp);
 265                         goto out;
 266                 }
 267
 268                 fd_install(fd, filp);
 269         }
 270
 271         return fd;
 272
 273 out:
 274         put_unused_fd(fd);
 275         return err;
 276 }
 277
 278 /* Open a file descriptor on an autofs mount point */
 279 static int autofs_dev_ioctl_openmount(struct file *fp,
 280                                       struct autofs_sb_info *sbi,
 281                                       struct autofs_dev_ioctl *param)
 282 {
 283         const char *path;
 284         dev_t devid;
 285         int err, fd;
 286
 287         /* param->path has already been checked */
 288         if (!param->openmount.devid)
 289                 return -EINVAL;
 290
 291         param->ioctlfd = -1;
 292
 293         path = param->path;
 294         devid = new_decode_dev(param->openmount.devid);
 295
 296         err = 0;
 297         fd = autofs_dev_ioctl_open_mountpoint(path, devid);
 298         if (unlikely(fd < 0)) {
 299                 err = fd;
 300                 goto out;
 301         }
 302
 303         param->ioctlfd = fd;
 304 out:
 305         return err;
 306 }
 307
 308 /* Close file descriptor allocated above (user can also use close(2)). */
 309 static int autofs_dev_ioctl_closemount(struct file *fp,
 310                                        struct autofs_sb_info *sbi,
 311                                        struct autofs_dev_ioctl *param)
 312 {
 313         return sys_close(param->ioctlfd);
 314 }
 315
 316 /*
 317  * Send "ready" status for an existing wait (either a mount or an expire
 318  * request).
 319  */
 320 static int autofs_dev_ioctl_ready(struct file *fp,
 321                                   struct autofs_sb_info *sbi,
 322                                   struct autofs_dev_ioctl *param)
 323 {
 324         autofs_wqt_t token;
 325
 326         token = (autofs_wqt_t) param->ready.token;
 327         return autofs4_wait_release(sbi, token, 0);
 328 }
 329
 330 /*
 331  * Send "fail" status for an existing wait (either a mount or an expire
 332  * request).
 333  */
 334 static int autofs_dev_ioctl_fail(struct file *fp,
 335                                  struct autofs_sb_info *sbi,
 336                                  struct autofs_dev_ioctl *param)
 337 {
 338         autofs_wqt_t token;
 339         int status;
 340
 341         token = (autofs_wqt_t) param->fail.token;
 342         status = param->fail.status < 0 ? param->fail.status : -ENOENT;
 343         return autofs4_wait_release(sbi, token, status);
 344 }
 345
 346 /*
 347  * Set the pipe fd for kernel communication to the daemon.
 348  *
 349  * Normally this is set at mount using an option but if we
 350  * are reconnecting to a busy mount then we need to use this
 351  * to tell the autofs mount about the new kernel pipe fd. In
 352  * order to protect mounts against incorrectly setting the
 353  * pipefd we also require that the autofs mount be catatonic.
 354  *
 355  * This also sets the process group id used to identify the
 356  * controlling process (eg. the owning automount(8) daemon).
 357  */
 358 static int autofs_dev_ioctl_setpipefd(struct file *fp,
 359                                       struct autofs_sb_info *sbi,
 360                                       struct autofs_dev_ioctl *param)
 361 {
 362         int pipefd;
 363         int err = 0;
 364         struct pid *new_pid = NULL;
 365
 366         if (param->setpipefd.pipefd == -1)
 367                 return -EINVAL;
 368
 369         pipefd = param->setpipefd.pipefd;
 370
 371         mutex_lock(&sbi->wq_mutex);
 372         if (!sbi->catatonic) {
 373                 mutex_unlock(&sbi->wq_mutex);
 374                 return -EBUSY;
 375         } else {
 376                 struct file *pipe;
 377
 378                 new_pid = get_task_pid(current, PIDTYPE_PGID);
 379
 380                 if (ns_of_pid(new_pid) != ns_of_pid(sbi->oz_pgrp)) {
 381                         pr_warn("not allowed to change PID namespace\n");
 382                         err = -EINVAL;
 383                         goto out;
 384                 }
 385
 386                 pipe = fget(pipefd);
 387                 if (!pipe) {
 388                         err = -EBADF;
 389                         goto out;
 390                 }
 391                 if (autofs_prepare_pipe(pipe) < 0) {
 392                         err = -EPIPE;
 393                         fput(pipe);
 394                         goto out;
 395                 }
 396                 swap(sbi->oz_pgrp, new_pid);
 397                 sbi->pipefd = pipefd;
 398                 sbi->pipe = pipe;
 399                 sbi->catatonic = 0;
 400         }
 401 out:
 402         put_pid(new_pid);
 403         mutex_unlock(&sbi->wq_mutex);
 404         return err;
 405 }
 406
 407 /*
 408  * Make the autofs mount point catatonic, no longer responsive to
 409  * mount requests. Also closes the kernel pipe file descriptor.
 410  */
 411 static int autofs_dev_ioctl_catatonic(struct file *fp,
 412                                       struct autofs_sb_info *sbi,
 413                                       struct autofs_dev_ioctl *param)
 414 {
 415         autofs4_catatonic_mode(sbi);
 416         return 0;
 417 }
 418
 419 /* Set the autofs mount timeout */
 420 static int autofs_dev_ioctl_timeout(struct file *fp,
 421                                     struct autofs_sb_info *sbi,
 422                                     struct autofs_dev_ioctl *param)
 423 {
 424         unsigned long timeout;
 425
 426         timeout = param->timeout.timeout;
 427         param->timeout.timeout = sbi->exp_timeout / HZ;
 428         sbi->exp_timeout = timeout * HZ;
 429         return 0;
 430 }
 431
 432 /*
 433  * Return the uid and gid of the last request for the mount
 434  *
 435  * When reconstructing an autofs mount tree with active mounts
 436  * we need to re-connect to mounts that may have used the original
 437  * process uid and gid (or string variations of them) for mount
 438  * lookups within the map entry.
 439  */
 440 static int autofs_dev_ioctl_requester(struct file *fp,
 441                                       struct autofs_sb_info *sbi,
 442                                       struct autofs_dev_ioctl *param)
 443 {
 444         struct autofs_info *ino;
 445         struct path path;
 446         dev_t devid;
 447         int err = -ENOENT;
 448
 449         if (param->size <= AUTOFS_DEV_IOCTL_SIZE) {
 450                 err = -EINVAL;
 451                 goto out;
 452         }
 453
 454         devid = sbi->sb->s_dev;
 455
 456         param->requester.uid = param->requester.gid = -1;
 457
 458         err = find_autofs_mount(param->path, &path, test_by_dev, &devid);
 459         if (err)
 460                 goto out;
 461
 462         ino = autofs4_dentry_ino(path.dentry);
 463         if (ino) {
 464                 err = 0;
 465                 autofs4_expire_wait(&path, 0);
 466                 spin_lock(&sbi->fs_lock);
 467                 param->requester.uid =
 468                         from_kuid_munged(current_user_ns(), ino->uid);
 469                 param->requester.gid =
 470                         from_kgid_munged(current_user_ns(), ino->gid);
 471                 spin_unlock(&sbi->fs_lock);
 472         }
 473         path_put(&path);
 474 out:
 475         return err;
 476 }
 477
 478 /*
 479  * Call repeatedly until it returns -EAGAIN, meaning there's nothing
 480  * more that can be done.
 481  */
 482 static int autofs_dev_ioctl_expire(struct file *fp,
 483                                    struct autofs_sb_info *sbi,
 484                                    struct autofs_dev_ioctl *param)
 485 {
 486         struct vfsmount *mnt;
 487         int how;
 488
 489         how = param->expire.how;
 490         mnt = fp->f_path.mnt;
 491
 492         return autofs4_do_expire_multi(sbi->sb, mnt, sbi, how);
 493 }
 494
 495 /* Check if autofs mount point is in use */
 496 static int autofs_dev_ioctl_askumount(struct file *fp,
 497                                       struct autofs_sb_info *sbi,
 498                                       struct autofs_dev_ioctl *param)
 499 {
 500         param->askumount.may_umount = 0;
 501         if (may_umount(fp->f_path.mnt))
 502                 param->askumount.may_umount = 1;
 503         return 0;
 504 }
 505
 506 /*
 507  * Check if the given path is a mountpoint.
 508  *
 509  * If we are supplied with the file descriptor of an autofs
 510  * mount we're looking for a specific mount. In this case
 511  * the path is considered a mountpoint if it is itself a
 512  * mountpoint or contains a mount, such as a multi-mount
 513  * without a root mount. In this case we return 1 if the
 514  * path is a mount point and the super magic of the covering
 515  * mount if there is one or 0 if it isn't a mountpoint.
 516  *
 517  * If we aren't supplied with a file descriptor then we
 518  * lookup the path and check if it is the root of a mount.
 519  * If a type is given we are looking for a particular autofs
 520  * mount and if we don't find a match we return fail. If the
 521  * located path is the root of a mount we return 1 along with
 522  * the super magic of the mount or 0 otherwise.
 523  *
 524  * In both cases the the device number (as returned by
 525  * new_encode_dev()) is also returned.
 526  */
 527 static int autofs_dev_ioctl_ismountpoint(struct file *fp,
 528                                          struct autofs_sb_info *sbi,
 529                                          struct autofs_dev_ioctl *param)
 530 {
 531         struct path path;
 532         const char *name;
 533         unsigned int type;
 534         unsigned int devid, magic;
 535         int err = -ENOENT;
 536
 537         if (param->size <= AUTOFS_DEV_IOCTL_SIZE) {
 538                 err = -EINVAL;
 539                 goto out;
 540         }
 541
 542         name = param->path;
 543         type = param->ismountpoint.in.type;
 544
 545         param->ismountpoint.out.devid = devid = 0;
 546         param->ismountpoint.out.magic = magic = 0;
 547
 548         if (!fp || param->ioctlfd == -1) {
 549                 if (autofs_type_any(type))
 550                         err = kern_path_mountpoint(AT_FDCWD,
 551                                                    name, &path, LOOKUP_FOLLOW);
 552                 else
 553                         err = find_autofs_mount(name, &path,
 554                                                 test_by_type, &type);
 555                 if (err)
 556                         goto out;
 557                 devid = new_encode_dev(path.dentry->d_sb->s_dev);
 558                 err = 0;
 559                 if (path.mnt->mnt_root == path.dentry) {
 560                         err = 1;
 561                         magic = path.dentry->d_sb->s_magic;
 562                 }
 563         } else {
 564                 dev_t dev = sbi->sb->s_dev;
 565
 566                 err = find_autofs_mount(name, &path, test_by_dev, &dev);
 567                 if (err)
 568                         goto out;
 569
 570                 devid = new_encode_dev(dev);
 571
 572                 err = path_has_submounts(&path);
 573
 574                 if (follow_down_one(&path))
 575                         magic = path.dentry->d_sb->s_magic;
 576         }
 577
 578         param->ismountpoint.out.devid = devid;
 579         param->ismountpoint.out.magic = magic;
 580         path_put(&path);
 581 out:
 582         return err;
 583 }
 584
 585 /*
 586  * Our range of ioctl numbers isn't 0 based so we need to shift
 587  * the array index by _IOC_NR(AUTOFS_CTL_IOC_FIRST) for the table
 588  * lookup.
 589  */
 590 #define cmd_idx(cmd)    (cmd - _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST))
 591
 592 static ioctl_fn lookup_dev_ioctl(unsigned int cmd)
 593 {
 594         static ioctl_fn _ioctls[] = {
 595                 autofs_dev_ioctl_version,
 596                 autofs_dev_ioctl_protover,
 597                 autofs_dev_ioctl_protosubver,
 598                 autofs_dev_ioctl_openmount,
 599                 autofs_dev_ioctl_closemount,
 600                 autofs_dev_ioctl_ready,
 601                 autofs_dev_ioctl_fail,
 602                 autofs_dev_ioctl_setpipefd,
 603                 autofs_dev_ioctl_catatonic,
 604                 autofs_dev_ioctl_timeout,
 605                 autofs_dev_ioctl_requester,
 606                 autofs_dev_ioctl_expire,
 607                 autofs_dev_ioctl_askumount,
 608                 autofs_dev_ioctl_ismountpoint,
 609         };
 610         unsigned int idx = cmd_idx(cmd);
 611
 612         return (idx >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[idx];
 613 }
 614
 615 /* ioctl dispatcher */
 616 static int _autofs_dev_ioctl(unsigned int command,
 617                              struct autofs_dev_ioctl __user *user)
 618 {
 619         struct autofs_dev_ioctl *param;
 620         struct file *fp;
 621         struct autofs_sb_info *sbi;
 622         unsigned int cmd_first, cmd;
 623         ioctl_fn fn = NULL;
 624         int err = 0;
 625
 626         cmd_first = _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST);
 627         cmd = _IOC_NR(command);
 628
 629         if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) ||
 630             cmd - cmd_first > AUTOFS_DEV_IOCTL_IOC_COUNT) {
 631                 return -ENOTTY;
 632         }
 633
 634         /* Only root can use ioctls other than AUTOFS_DEV_IOCTL_VERSION_CMD
 635          * and AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD
 636          */
 637         if (cmd != AUTOFS_DEV_IOCTL_VERSION_CMD &&
 638             cmd != AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD &&
 639             !capable(CAP_SYS_ADMIN))
 640                 return -EPERM;
 641
 642         /* Copy the parameters into kernel space. */
 643         param = copy_dev_ioctl(user);
 644         if (IS_ERR(param))
 645                 return PTR_ERR(param);
 646
 647         err = validate_dev_ioctl(command, param);
 648         if (err)
 649                 goto out;
 650
 651         fn = lookup_dev_ioctl(cmd);
 652         if (!fn) {
 653                 pr_warn("unknown command 0x%08x\n", command);
 654                 err = -ENOTTY;
 655                 goto out;
 656         }
 657
 658         fp = NULL;
 659         sbi = NULL;
 660
 661         /*
 662          * For obvious reasons the openmount can't have a file
 663          * descriptor yet. We don't take a reference to the
 664          * file during close to allow for immediate release,
 665          * and the same for retrieving ioctl version.
 666          */
 667         if (cmd != AUTOFS_DEV_IOCTL_VERSION_CMD &&
 668             cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD &&
 669             cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) {
 670                 fp = fget(param->ioctlfd);
 671                 if (!fp) {
 672                         if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD)
 673                                 goto cont;
 674                         err = -EBADF;
 675                         goto out;
 676                 }
 677
 678                 sbi = autofs_dev_ioctl_sbi(fp);
 679                 if (!sbi || sbi->magic != AUTOFS_SBI_MAGIC) {
 680                         err = -EINVAL;
 681                         fput(fp);
 682                         goto out;
 683                 }
 684
 685                 /*
 686                  * Admin needs to be able to set the mount catatonic in
 687                  * order to be able to perform the re-open.
 688                  */
 689                 if (!autofs4_oz_mode(sbi) &&
 690                     cmd != AUTOFS_DEV_IOCTL_CATATONIC_CMD) {
 691                         err = -EACCES;
 692                         fput(fp);
 693                         goto out;
 694                 }
 695         }
 696 cont:
 697         err = fn(fp, sbi, param);
 698
 699         if (fp)
 700                 fput(fp);
 701         if (err >= 0 && copy_to_user(user, param, AUTOFS_DEV_IOCTL_SIZE))
 702                 err = -EFAULT;
 703 out:
 704         free_dev_ioctl(param);
 705         return err;
 706 }
 707
 708 static long autofs_dev_ioctl(struct file *file, unsigned int command,
 709                              unsigned long u)
 710 {
 711         int err;
 712
 713         err = _autofs_dev_ioctl(command, (struct autofs_dev_ioctl __user *) u);
 714         return (long) err;
 715 }
 716
 717 #ifdef CONFIG_COMPAT
 718 static long autofs_dev_ioctl_compat(struct file *file, unsigned int command,
 719                                     unsigned long u)
 720 {
 721         return autofs_dev_ioctl(file, command, (unsigned long) compat_ptr(u));
 722 }
 723 #else
 724 #define autofs_dev_ioctl_compat NULL
 725 #endif
 726
 727 static const struct file_operations _dev_ioctl_fops = {
 728         .unlocked_ioctl  = autofs_dev_ioctl,
 729         .compat_ioctl = autofs_dev_ioctl_compat,
 730         .owner   = THIS_MODULE,
 731         .llseek = noop_llseek,
 732 };
 733
 734 static struct miscdevice _autofs_dev_ioctl_misc = {
 735         .minor          = AUTOFS_MINOR,
 736         .name           = AUTOFS_DEVICE_NAME,
 737         .fops           = &_dev_ioctl_fops,
 738         .mode           = 0644,
 739 };
 740
 741 MODULE_ALIAS_MISCDEV(AUTOFS_MINOR);
 742 MODULE_ALIAS("devname:autofs");
 743
 744 /* Register/deregister misc character device */
 745 int __init autofs_dev_ioctl_init(void)
 746 {
 747         int r;
 748
 749         r = misc_register(&_autofs_dev_ioctl_misc);
 750         if (r) {
 751                 pr_err("misc_register failed for control device\n");
 752                 return r;
 753         }
 754
 755         return 0;
 756 }
 757
 758 void autofs_dev_ioctl_exit(void)
 759 {
 760         misc_deregister(&_autofs_dev_ioctl_misc);
 761 }