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> |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 22 | #include <linux/magic.h> |
| 23 | #include <linux/dcache.h> |
| 24 | #include <linux/uaccess.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 25 | #include <linux/slab.h> |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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 | */ |
Al Viro | 3eac877 | 2009-04-07 11:12:46 -0400 | [diff] [blame] | 57 | static int invalid_str(char *str, size_t size) |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 58 | { |
Al Viro | 3eac877 | 2009-04-07 11:12:46 -0400 | [diff] [blame] | 59 | if (memchr(str, 0, size)) |
| 60 | return 0; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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 | { |
Julia Lawall | 7ca5ca6 | 2010-05-26 14:42:13 -0700 | [diff] [blame] | 98 | struct autofs_dev_ioctl tmp; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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 | |
Julia Lawall | 7ca5ca6 | 2010-05-26 14:42:13 -0700 | [diff] [blame] | 106 | return memdup_user(in, tmp.size); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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 |
Ian Kent | bae8ec6 | 2009-01-06 14:42:09 -0800 | [diff] [blame] | 117 | * check that it is terminated and contains at least one "/". |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 118 | */ |
| 119 | static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param) |
| 120 | { |
Ian Kent | 96b0317 | 2008-11-06 12:53:23 -0800 | [diff] [blame] | 121 | int err; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 122 | |
Ian Kent | 96b0317 | 2008-11-06 12:53:23 -0800 | [diff] [blame] | 123 | err = check_dev_ioctl_version(cmd, param); |
| 124 | if (err) { |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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)) { |
Al Viro | 3eac877 | 2009-04-07 11:12:46 -0400 | [diff] [blame] | 131 | err = invalid_str(param->path, param->size - sizeof(*param)); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 132 | if (err) { |
Ian Kent | bae8ec6 | 2009-01-06 14:42:09 -0800 | [diff] [blame] | 133 | AUTOFS_WARN( |
| 134 | "path string terminator missing for cmd(0x%08x)", |
| 135 | cmd); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 136 | goto out; |
| 137 | } |
| 138 | |
Ian Kent | bae8ec6 | 2009-01-06 14:42:09 -0800 | [diff] [blame] | 139 | err = check_name(param->path); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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) { |
| 162 | inode = f->f_path.dentry->d_inode; |
| 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 | { |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 173 | param->protover.version = sbi->version; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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 | { |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 182 | param->protosubver.sub_version = sbi->sub_version; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 183 | return 0; |
| 184 | } |
| 185 | |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 186 | static int find_autofs_mount(const char *pathname, |
| 187 | struct path *res, |
| 188 | int test(struct path *path, void *data), |
| 189 | void *data) |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 190 | { |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 191 | struct path path; |
| 192 | int err = kern_path(pathname, 0, &path); |
| 193 | if (err) |
| 194 | return err; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 195 | err = -ENOENT; |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 196 | while (path.dentry == path.mnt->mnt_root) { |
Al Viro | d8c9584 | 2011-12-07 18:16:57 -0500 | [diff] [blame] | 197 | if (path.dentry->d_sb->s_magic == AUTOFS_SUPER_MAGIC) { |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 198 | if (test(&path, data)) { |
| 199 | path_get(&path); |
| 200 | if (!err) /* already found some */ |
| 201 | path_put(res); |
| 202 | *res = path; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 203 | err = 0; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 204 | } |
| 205 | } |
Al Viro | bab77eb | 2009-04-18 03:26:48 -0400 | [diff] [blame] | 206 | if (!follow_up(&path)) |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 207 | break; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 208 | } |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 209 | path_put(&path); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 210 | return err; |
| 211 | } |
| 212 | |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 213 | static int test_by_dev(struct path *path, void *p) |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 214 | { |
Al Viro | d8c9584 | 2011-12-07 18:16:57 -0500 | [diff] [blame] | 215 | return path->dentry->d_sb->s_dev == *(dev_t *)p; |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 216 | } |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 217 | |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 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; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 222 | } |
| 223 | |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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 | */ |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 228 | static int autofs_dev_ioctl_open_mountpoint(const char *name, dev_t devid) |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 229 | { |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 230 | int err, fd; |
| 231 | |
Al Viro | c921b40 | 2012-08-12 18:04:37 -0400 | [diff] [blame] | 232 | fd = get_unused_fd_flags(O_CLOEXEC); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 233 | if (likely(fd >= 0)) { |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 234 | struct file *filp; |
| 235 | struct path path; |
| 236 | |
| 237 | err = find_autofs_mount(name, &path, test_by_dev, &devid); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 238 | if (err) |
| 239 | goto out; |
| 240 | |
| 241 | /* |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 242 | * Find autofs super block that has the device number |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 243 | * corresponding to the autofs fs we want to open. |
| 244 | */ |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 245 | |
Al Viro | 765927b | 2012-06-26 21:58:53 +0400 | [diff] [blame] | 246 | filp = dentry_open(&path, O_RDONLY, current_cred()); |
| 247 | path_put(&path); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 248 | if (IS_ERR(filp)) { |
| 249 | err = PTR_ERR(filp); |
| 250 | goto out; |
| 251 | } |
| 252 | |
Al Viro | c921b40 | 2012-08-12 18:04:37 -0400 | [diff] [blame] | 253 | fd_install(fd, filp); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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 */ |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 273 | if (!param->openmount.devid) |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 274 | return -EINVAL; |
| 275 | |
| 276 | param->ioctlfd = -1; |
| 277 | |
| 278 | path = param->path; |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 279 | devid = new_decode_dev(param->openmount.devid); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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 | |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 311 | token = (autofs_wqt_t) param->ready.token; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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 | |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 326 | token = (autofs_wqt_t) param->fail.token; |
| 327 | status = param->fail.status ? param->fail.status : -ENOENT; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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 | |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 350 | if (param->setpipefd.pipefd == -1) |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 351 | return -EINVAL; |
| 352 | |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 353 | pipefd = param->setpipefd.pipefd; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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); |
Jesper Juhl | 3dc8fe4 | 2011-03-25 01:51:37 +0800 | [diff] [blame] | 361 | if (!pipe) { |
| 362 | err = -EBADF; |
| 363 | goto out; |
| 364 | } |
Linus Torvalds | 64f371b | 2012-04-29 13:30:08 -0700 | [diff] [blame] | 365 | if (autofs_prepare_pipe(pipe) < 0) { |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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 | |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 399 | timeout = param->timeout.timeout; |
| 400 | param->timeout.timeout = sbi->exp_timeout / HZ; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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; |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 418 | struct path path; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 419 | dev_t devid; |
| 420 | int err = -ENOENT; |
| 421 | |
| 422 | if (param->size <= sizeof(*param)) { |
| 423 | err = -EINVAL; |
| 424 | goto out; |
| 425 | } |
| 426 | |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 427 | devid = sbi->sb->s_dev; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 428 | |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 429 | param->requester.uid = param->requester.gid = -1; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 430 | |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 431 | err = find_autofs_mount(param->path, &path, test_by_dev, &devid); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 432 | if (err) |
| 433 | goto out; |
| 434 | |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 435 | ino = autofs4_dentry_ino(path.dentry); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 436 | if (ino) { |
| 437 | err = 0; |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 438 | autofs4_expire_wait(path.dentry); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 439 | spin_lock(&sbi->fs_lock); |
Eric W. Biederman | 45634cd | 2012-02-07 16:18:52 -0800 | [diff] [blame] | 440 | param->requester.uid = from_kuid_munged(current_user_ns(), ino->uid); |
| 441 | param->requester.gid = from_kgid_munged(current_user_ns(), ino->gid); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 442 | spin_unlock(&sbi->fs_lock); |
| 443 | } |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 444 | path_put(&path); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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 | { |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 457 | struct vfsmount *mnt; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 458 | int how; |
| 459 | |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 460 | how = param->expire.how; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 461 | mnt = fp->f_path.mnt; |
| 462 | |
Ian Kent | 56fcef7 | 2009-03-31 15:24:43 -0700 | [diff] [blame] | 463 | return autofs4_do_expire_multi(sbi->sb, mnt, sbi, how); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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 | { |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 471 | param->askumount.may_umount = 0; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 472 | if (may_umount(fp->f_path.mnt)) |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 473 | param->askumount.may_umount = 1; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 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 |
| 489 | * lookup the nameidata of the path and check if it is the |
| 490 | * root of a mount. If a type is given we are looking for |
| 491 | * a particular autofs mount and if we don't find a match |
| 492 | * we return fail. If the located nameidata path is the |
| 493 | * root of a mount we return 1 along with the super magic |
| 494 | * of the mount or 0 otherwise. |
| 495 | * |
| 496 | * In both cases the the device number (as returned by |
| 497 | * new_encode_dev()) is also returned. |
| 498 | */ |
| 499 | static int autofs_dev_ioctl_ismountpoint(struct file *fp, |
| 500 | struct autofs_sb_info *sbi, |
| 501 | struct autofs_dev_ioctl *param) |
| 502 | { |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 503 | struct path path; |
| 504 | const char *name; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 505 | unsigned int type; |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 506 | unsigned int devid, magic; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 507 | int err = -ENOENT; |
| 508 | |
| 509 | if (param->size <= sizeof(*param)) { |
| 510 | err = -EINVAL; |
| 511 | goto out; |
| 512 | } |
| 513 | |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 514 | name = param->path; |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 515 | type = param->ismountpoint.in.type; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 516 | |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 517 | param->ismountpoint.out.devid = devid = 0; |
| 518 | param->ismountpoint.out.magic = magic = 0; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 519 | |
| 520 | if (!fp || param->ioctlfd == -1) { |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 521 | if (autofs_type_any(type)) |
| 522 | err = kern_path(name, LOOKUP_FOLLOW, &path); |
| 523 | else |
| 524 | err = find_autofs_mount(name, &path, test_by_type, &type); |
| 525 | if (err) |
| 526 | goto out; |
Al Viro | d8c9584 | 2011-12-07 18:16:57 -0500 | [diff] [blame] | 527 | devid = new_encode_dev(path.dentry->d_sb->s_dev); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 528 | err = 0; |
Al Viro | f598f9f | 2010-01-23 20:08:53 -0500 | [diff] [blame] | 529 | if (path.mnt->mnt_root == path.dentry) { |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 530 | err = 1; |
Al Viro | d8c9584 | 2011-12-07 18:16:57 -0500 | [diff] [blame] | 531 | magic = path.dentry->d_sb->s_magic; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 532 | } |
| 533 | } else { |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 534 | dev_t dev = sbi->sb->s_dev; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 535 | |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 536 | err = find_autofs_mount(name, &path, test_by_dev, &dev); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 537 | if (err) |
| 538 | goto out; |
| 539 | |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 540 | devid = new_encode_dev(dev); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 541 | |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 542 | err = have_submounts(path.dentry); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 543 | |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 544 | if (follow_down_one(&path)) |
Al Viro | d8c9584 | 2011-12-07 18:16:57 -0500 | [diff] [blame] | 545 | magic = path.dentry->d_sb->s_magic; |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 546 | } |
| 547 | |
Ian Kent | 730c9ee | 2009-01-06 14:42:06 -0800 | [diff] [blame] | 548 | param->ismountpoint.out.devid = devid; |
| 549 | param->ismountpoint.out.magic = magic; |
Al Viro | 4e44b68 | 2009-04-07 11:08:56 -0400 | [diff] [blame] | 550 | path_put(&path); |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 551 | out: |
| 552 | return err; |
| 553 | } |
| 554 | |
| 555 | /* |
| 556 | * Our range of ioctl numbers isn't 0 based so we need to shift |
| 557 | * the array index by _IOC_NR(AUTOFS_CTL_IOC_FIRST) for the table |
| 558 | * lookup. |
| 559 | */ |
| 560 | #define cmd_idx(cmd) (cmd - _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST)) |
| 561 | |
| 562 | static ioctl_fn lookup_dev_ioctl(unsigned int cmd) |
| 563 | { |
| 564 | static struct { |
| 565 | int cmd; |
| 566 | ioctl_fn fn; |
| 567 | } _ioctls[] = { |
| 568 | {cmd_idx(AUTOFS_DEV_IOCTL_VERSION_CMD), NULL}, |
| 569 | {cmd_idx(AUTOFS_DEV_IOCTL_PROTOVER_CMD), |
| 570 | autofs_dev_ioctl_protover}, |
| 571 | {cmd_idx(AUTOFS_DEV_IOCTL_PROTOSUBVER_CMD), |
| 572 | autofs_dev_ioctl_protosubver}, |
| 573 | {cmd_idx(AUTOFS_DEV_IOCTL_OPENMOUNT_CMD), |
| 574 | autofs_dev_ioctl_openmount}, |
| 575 | {cmd_idx(AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD), |
| 576 | autofs_dev_ioctl_closemount}, |
| 577 | {cmd_idx(AUTOFS_DEV_IOCTL_READY_CMD), |
| 578 | autofs_dev_ioctl_ready}, |
| 579 | {cmd_idx(AUTOFS_DEV_IOCTL_FAIL_CMD), |
| 580 | autofs_dev_ioctl_fail}, |
| 581 | {cmd_idx(AUTOFS_DEV_IOCTL_SETPIPEFD_CMD), |
| 582 | autofs_dev_ioctl_setpipefd}, |
| 583 | {cmd_idx(AUTOFS_DEV_IOCTL_CATATONIC_CMD), |
| 584 | autofs_dev_ioctl_catatonic}, |
| 585 | {cmd_idx(AUTOFS_DEV_IOCTL_TIMEOUT_CMD), |
| 586 | autofs_dev_ioctl_timeout}, |
| 587 | {cmd_idx(AUTOFS_DEV_IOCTL_REQUESTER_CMD), |
| 588 | autofs_dev_ioctl_requester}, |
| 589 | {cmd_idx(AUTOFS_DEV_IOCTL_EXPIRE_CMD), |
| 590 | autofs_dev_ioctl_expire}, |
| 591 | {cmd_idx(AUTOFS_DEV_IOCTL_ASKUMOUNT_CMD), |
| 592 | autofs_dev_ioctl_askumount}, |
| 593 | {cmd_idx(AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD), |
| 594 | autofs_dev_ioctl_ismountpoint} |
| 595 | }; |
| 596 | unsigned int idx = cmd_idx(cmd); |
| 597 | |
| 598 | return (idx >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[idx].fn; |
| 599 | } |
| 600 | |
| 601 | /* ioctl dispatcher */ |
| 602 | static int _autofs_dev_ioctl(unsigned int command, struct autofs_dev_ioctl __user *user) |
| 603 | { |
| 604 | struct autofs_dev_ioctl *param; |
| 605 | struct file *fp; |
| 606 | struct autofs_sb_info *sbi; |
| 607 | unsigned int cmd_first, cmd; |
| 608 | ioctl_fn fn = NULL; |
| 609 | int err = 0; |
| 610 | |
| 611 | /* only root can play with this */ |
| 612 | if (!capable(CAP_SYS_ADMIN)) |
| 613 | return -EPERM; |
| 614 | |
| 615 | cmd_first = _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST); |
| 616 | cmd = _IOC_NR(command); |
| 617 | |
| 618 | if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) || |
| 619 | cmd - cmd_first >= AUTOFS_DEV_IOCTL_IOC_COUNT) { |
| 620 | return -ENOTTY; |
| 621 | } |
| 622 | |
| 623 | /* Copy the parameters into kernel space. */ |
| 624 | param = copy_dev_ioctl(user); |
| 625 | if (IS_ERR(param)) |
| 626 | return PTR_ERR(param); |
| 627 | |
| 628 | err = validate_dev_ioctl(command, param); |
| 629 | if (err) |
| 630 | goto out; |
| 631 | |
| 632 | /* The validate routine above always sets the version */ |
| 633 | if (cmd == AUTOFS_DEV_IOCTL_VERSION_CMD) |
| 634 | goto done; |
| 635 | |
| 636 | fn = lookup_dev_ioctl(cmd); |
| 637 | if (!fn) { |
| 638 | AUTOFS_WARN("unknown command 0x%08x", command); |
| 639 | return -ENOTTY; |
| 640 | } |
| 641 | |
| 642 | fp = NULL; |
| 643 | sbi = NULL; |
| 644 | |
| 645 | /* |
| 646 | * For obvious reasons the openmount can't have a file |
| 647 | * descriptor yet. We don't take a reference to the |
| 648 | * file during close to allow for immediate release. |
| 649 | */ |
| 650 | if (cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD && |
| 651 | cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) { |
| 652 | fp = fget(param->ioctlfd); |
| 653 | if (!fp) { |
| 654 | if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) |
| 655 | goto cont; |
| 656 | err = -EBADF; |
| 657 | goto out; |
| 658 | } |
| 659 | |
| 660 | if (!fp->f_op) { |
| 661 | err = -ENOTTY; |
| 662 | fput(fp); |
| 663 | goto out; |
| 664 | } |
| 665 | |
| 666 | sbi = autofs_dev_ioctl_sbi(fp); |
| 667 | if (!sbi || sbi->magic != AUTOFS_SBI_MAGIC) { |
| 668 | err = -EINVAL; |
| 669 | fput(fp); |
| 670 | goto out; |
| 671 | } |
| 672 | |
| 673 | /* |
| 674 | * Admin needs to be able to set the mount catatonic in |
| 675 | * order to be able to perform the re-open. |
| 676 | */ |
| 677 | if (!autofs4_oz_mode(sbi) && |
| 678 | cmd != AUTOFS_DEV_IOCTL_CATATONIC_CMD) { |
| 679 | err = -EACCES; |
| 680 | fput(fp); |
| 681 | goto out; |
| 682 | } |
| 683 | } |
| 684 | cont: |
| 685 | err = fn(fp, sbi, param); |
| 686 | |
| 687 | if (fp) |
| 688 | fput(fp); |
| 689 | done: |
| 690 | if (err >= 0 && copy_to_user(user, param, AUTOFS_DEV_IOCTL_SIZE)) |
| 691 | err = -EFAULT; |
| 692 | out: |
| 693 | free_dev_ioctl(param); |
| 694 | return err; |
| 695 | } |
| 696 | |
| 697 | static long autofs_dev_ioctl(struct file *file, uint command, ulong u) |
| 698 | { |
| 699 | int err; |
| 700 | err = _autofs_dev_ioctl(command, (struct autofs_dev_ioctl __user *) u); |
| 701 | return (long) err; |
| 702 | } |
| 703 | |
| 704 | #ifdef CONFIG_COMPAT |
| 705 | static long autofs_dev_ioctl_compat(struct file *file, uint command, ulong u) |
| 706 | { |
| 707 | return (long) autofs_dev_ioctl(file, command, (ulong) compat_ptr(u)); |
| 708 | } |
| 709 | #else |
| 710 | #define autofs_dev_ioctl_compat NULL |
| 711 | #endif |
| 712 | |
| 713 | static const struct file_operations _dev_ioctl_fops = { |
| 714 | .unlocked_ioctl = autofs_dev_ioctl, |
| 715 | .compat_ioctl = autofs_dev_ioctl_compat, |
| 716 | .owner = THIS_MODULE, |
Arnd Bergmann | 6038f37 | 2010-08-15 18:52:59 +0200 | [diff] [blame] | 717 | .llseek = noop_llseek, |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 718 | }; |
| 719 | |
| 720 | static struct miscdevice _autofs_dev_ioctl_misc = { |
Kay Sievers | 578454f | 2010-05-20 18:07:20 +0200 | [diff] [blame] | 721 | .minor = AUTOFS_MINOR, |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 722 | .name = AUTOFS_DEVICE_NAME, |
| 723 | .fops = &_dev_ioctl_fops |
| 724 | }; |
| 725 | |
Kay Sievers | 578454f | 2010-05-20 18:07:20 +0200 | [diff] [blame] | 726 | MODULE_ALIAS_MISCDEV(AUTOFS_MINOR); |
| 727 | MODULE_ALIAS("devname:autofs"); |
| 728 | |
Ian Kent | 8d7b48e | 2008-10-15 22:02:54 -0700 | [diff] [blame] | 729 | /* Register/deregister misc character device */ |
| 730 | int autofs_dev_ioctl_init(void) |
| 731 | { |
| 732 | int r; |
| 733 | |
| 734 | r = misc_register(&_autofs_dev_ioctl_misc); |
| 735 | if (r) { |
| 736 | AUTOFS_ERROR("misc_register failed for control device"); |
| 737 | return r; |
| 738 | } |
| 739 | |
| 740 | return 0; |
| 741 | } |
| 742 | |
| 743 | void autofs_dev_ioctl_exit(void) |
| 744 | { |
| 745 | misc_deregister(&_autofs_dev_ioctl_misc); |
| 746 | return; |
| 747 | } |
| 748 | |