+++ /dev/null
-/*
- * Copyright 2008 Red Hat, Inc. All rights reserved.
- * Copyright 2008 Ian Kent <raven@themaw.net>
- *
- * This file is part of the Linux kernel and is made available under
- * the terms of the GNU General Public License, version 2, or at your
- * option, any later version, incorporated herein by reference.
- */
-
-#include <linux/module.h>
-#include <linux/vmalloc.h>
-#include <linux/miscdevice.h>
-#include <linux/init.h>
-#include <linux/wait.h>
-#include <linux/namei.h>
-#include <linux/fcntl.h>
-#include <linux/file.h>
-#include <linux/fdtable.h>
-#include <linux/sched.h>
-#include <linux/cred.h>
-#include <linux/compat.h>
-#include <linux/syscalls.h>
-#include <linux/magic.h>
-#include <linux/dcache.h>
-#include <linux/uaccess.h>
-#include <linux/slab.h>
-
-#include "autofs_i.h"
-
-/*
- * This module implements an interface for routing autofs ioctl control
- * commands via a miscellaneous device file.
- *
- * The alternate interface is needed because we need to be able open
- * an ioctl file descriptor on an autofs mount that may be covered by
- * another mount. This situation arises when starting automount(8)
- * or other user space daemon which uses direct mounts or offset
- * mounts (used for autofs lazy mount/umount of nested mount trees),
- * which have been left busy at at service shutdown.
- */
-
-typedef int (*ioctl_fn)(struct file *, struct autofs_sb_info *,
- struct autofs_dev_ioctl *);
-
-static int check_name(const char *name)
-{
- if (!strchr(name, '/'))
- return -EINVAL;
- return 0;
-}
-
-/*
- * Check a string doesn't overrun the chunk of
- * memory we copied from user land.
- */
-static int invalid_str(char *str, size_t size)
-{
- if (memchr(str, 0, size))
- return 0;
- return -EINVAL;
-}
-
-/*
- * Check that the user compiled against correct version of autofs
- * misc device code.
- *
- * As well as checking the version compatibility this always copies
- * the kernel interface version out.
- */
-static int check_dev_ioctl_version(int cmd, struct autofs_dev_ioctl *param)
-{
- int err = 0;
-
- if ((param->ver_major != AUTOFS_DEV_IOCTL_VERSION_MAJOR) ||
- (param->ver_minor > AUTOFS_DEV_IOCTL_VERSION_MINOR)) {
- pr_warn("ioctl control interface version mismatch: "
- "kernel(%u.%u), user(%u.%u), cmd(0x%08x)\n",
- AUTOFS_DEV_IOCTL_VERSION_MAJOR,
- AUTOFS_DEV_IOCTL_VERSION_MINOR,
- param->ver_major, param->ver_minor, cmd);
- err = -EINVAL;
- }
-
- /* Fill in the kernel version. */
- param->ver_major = AUTOFS_DEV_IOCTL_VERSION_MAJOR;
- param->ver_minor = AUTOFS_DEV_IOCTL_VERSION_MINOR;
-
- return err;
-}
-
-/*
- * Copy parameter control struct, including a possible path allocated
- * at the end of the struct.
- */
-static struct autofs_dev_ioctl *
-copy_dev_ioctl(struct autofs_dev_ioctl __user *in)
-{
- struct autofs_dev_ioctl tmp, *res;
-
- if (copy_from_user(&tmp, in, AUTOFS_DEV_IOCTL_SIZE))
- return ERR_PTR(-EFAULT);
-
- if (tmp.size < AUTOFS_DEV_IOCTL_SIZE)
- return ERR_PTR(-EINVAL);
-
- if (tmp.size > AUTOFS_DEV_IOCTL_SIZE + PATH_MAX)
- return ERR_PTR(-ENAMETOOLONG);
-
- res = memdup_user(in, tmp.size);
- if (!IS_ERR(res))
- res->size = tmp.size;
-
- return res;
-}
-
-static inline void free_dev_ioctl(struct autofs_dev_ioctl *param)
-{
- kfree(param);
-}
-
-/*
- * Check sanity of parameter control fields and if a path is present
- * check that it is terminated and contains at least one "/".
- */
-static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param)
-{
- int err;
-
- err = check_dev_ioctl_version(cmd, param);
- if (err) {
- pr_warn("invalid device control module version "
- "supplied for cmd(0x%08x)\n", cmd);
- goto out;
- }
-
- if (param->size > AUTOFS_DEV_IOCTL_SIZE) {
- err = invalid_str(param->path, param->size - AUTOFS_DEV_IOCTL_SIZE);
- if (err) {
- pr_warn(
- "path string terminator missing for cmd(0x%08x)\n",
- cmd);
- goto out;
- }
-
- err = check_name(param->path);
- if (err) {
- pr_warn("invalid path supplied for cmd(0x%08x)\n",
- cmd);
- goto out;
- }
- }
-
- err = 0;
-out:
- return err;
-}
-
-/*
- * Get the autofs super block info struct from the file opened on
- * the autofs mount point.
- */
-static struct autofs_sb_info *autofs_dev_ioctl_sbi(struct file *f)
-{
- struct autofs_sb_info *sbi = NULL;
- struct inode *inode;
-
- if (f) {
- inode = file_inode(f);
- sbi = autofs_sbi(inode->i_sb);
- }
- return sbi;
-}
-
-/* Return autofs dev ioctl version */
-static int autofs_dev_ioctl_version(struct file *fp,
- struct autofs_sb_info *sbi,
- struct autofs_dev_ioctl *param)
-{
- /* This should have already been set. */
- param->ver_major = AUTOFS_DEV_IOCTL_VERSION_MAJOR;
- param->ver_minor = AUTOFS_DEV_IOCTL_VERSION_MINOR;
- return 0;
-}
-
-/* Return autofs module protocol version */
-static int autofs_dev_ioctl_protover(struct file *fp,
- struct autofs_sb_info *sbi,
- struct autofs_dev_ioctl *param)
-{
- param->protover.version = sbi->version;
- return 0;
-}
-
-/* Return autofs module protocol sub version */
-static int autofs_dev_ioctl_protosubver(struct file *fp,
- struct autofs_sb_info *sbi,
- struct autofs_dev_ioctl *param)
-{
- param->protosubver.sub_version = sbi->sub_version;
- return 0;
-}
-
-/* Find the topmost mount satisfying test() */
-static int find_autofs_mount(const char *pathname,
- struct path *res,
- int test(const struct path *path, void *data),
- void *data)
-{
- struct path path;
- int err;
-
- err = kern_path_mountpoint(AT_FDCWD, pathname, &path, 0);
- if (err)
- return err;
- err = -ENOENT;
- while (path.dentry == path.mnt->mnt_root) {
- if (path.dentry->d_sb->s_magic == AUTOFS_SUPER_MAGIC) {
- if (test(&path, data)) {
- path_get(&path);
- *res = path;
- err = 0;
- break;
- }
- }
- if (!follow_up(&path))
- break;
- }
- path_put(&path);
- return err;
-}
-
-static int test_by_dev(const struct path *path, void *p)
-{
- return path->dentry->d_sb->s_dev == *(dev_t *)p;
-}
-
-static int test_by_type(const struct path *path, void *p)
-{
- struct autofs_info *ino = autofs_dentry_ino(path->dentry);
-
- return ino && ino->sbi->type & *(unsigned *)p;
-}
-
-/*
- * Open a file descriptor on the autofs mount point corresponding
- * to the given path and device number (aka. new_encode_dev(sb->s_dev)).
- */
-static int autofs_dev_ioctl_open_mountpoint(const char *name, dev_t devid)
-{
- int err, fd;
-
- fd = get_unused_fd_flags(O_CLOEXEC);
- if (likely(fd >= 0)) {
- struct file *filp;
- struct path path;
-
- err = find_autofs_mount(name, &path, test_by_dev, &devid);
- if (err)
- goto out;
-
- filp = dentry_open(&path, O_RDONLY, current_cred());
- path_put(&path);
- if (IS_ERR(filp)) {
- err = PTR_ERR(filp);
- goto out;
- }
-
- fd_install(fd, filp);
- }
-
- return fd;
-
-out:
- put_unused_fd(fd);
- return err;
-}
-
-/* Open a file descriptor on an autofs mount point */
-static int autofs_dev_ioctl_openmount(struct file *fp,
- struct autofs_sb_info *sbi,
- struct autofs_dev_ioctl *param)
-{
- const char *path;
- dev_t devid;
- int err, fd;
-
- /* param->path has already been checked */
- if (!param->openmount.devid)
- return -EINVAL;
-
- param->ioctlfd = -1;
-
- path = param->path;
- devid = new_decode_dev(param->openmount.devid);
-
- err = 0;
- fd = autofs_dev_ioctl_open_mountpoint(path, devid);
- if (unlikely(fd < 0)) {
- err = fd;
- goto out;
- }
-
- param->ioctlfd = fd;
-out:
- return err;
-}
-
-/* Close file descriptor allocated above (user can also use close(2)). */
-static int autofs_dev_ioctl_closemount(struct file *fp,
- struct autofs_sb_info *sbi,
- struct autofs_dev_ioctl *param)
-{
- return ksys_close(param->ioctlfd);
-}
-
-/*
- * Send "ready" status for an existing wait (either a mount or an expire
- * request).
- */
-static int autofs_dev_ioctl_ready(struct file *fp,
- struct autofs_sb_info *sbi,
- struct autofs_dev_ioctl *param)
-{
- autofs_wqt_t token;
-
- token = (autofs_wqt_t) param->ready.token;
- return autofs_wait_release(sbi, token, 0);
-}
-
-/*
- * Send "fail" status for an existing wait (either a mount or an expire
- * request).
- */
-static int autofs_dev_ioctl_fail(struct file *fp,
- struct autofs_sb_info *sbi,
- struct autofs_dev_ioctl *param)
-{
- autofs_wqt_t token;
- int status;
-
- token = (autofs_wqt_t) param->fail.token;
- status = param->fail.status < 0 ? param->fail.status : -ENOENT;
- return autofs_wait_release(sbi, token, status);
-}
-
-/*
- * Set the pipe fd for kernel communication to the daemon.
- *
- * Normally this is set at mount using an option but if we
- * are reconnecting to a busy mount then we need to use this
- * to tell the autofs mount about the new kernel pipe fd. In
- * order to protect mounts against incorrectly setting the
- * pipefd we also require that the autofs mount be catatonic.
- *
- * This also sets the process group id used to identify the
- * controlling process (eg. the owning automount(8) daemon).
- */
-static int autofs_dev_ioctl_setpipefd(struct file *fp,
- struct autofs_sb_info *sbi,
- struct autofs_dev_ioctl *param)
-{
- int pipefd;
- int err = 0;
- struct pid *new_pid = NULL;
-
- if (param->setpipefd.pipefd == -1)
- return -EINVAL;
-
- pipefd = param->setpipefd.pipefd;
-
- mutex_lock(&sbi->wq_mutex);
- if (!sbi->catatonic) {
- mutex_unlock(&sbi->wq_mutex);
- return -EBUSY;
- } else {
- struct file *pipe;
-
- new_pid = get_task_pid(current, PIDTYPE_PGID);
-
- if (ns_of_pid(new_pid) != ns_of_pid(sbi->oz_pgrp)) {
- pr_warn("not allowed to change PID namespace\n");
- err = -EINVAL;
- goto out;
- }
-
- pipe = fget(pipefd);
- if (!pipe) {
- err = -EBADF;
- goto out;
- }
- if (autofs_prepare_pipe(pipe) < 0) {
- err = -EPIPE;
- fput(pipe);
- goto out;
- }
- swap(sbi->oz_pgrp, new_pid);
- sbi->pipefd = pipefd;
- sbi->pipe = pipe;
- sbi->catatonic = 0;
- }
-out:
- put_pid(new_pid);
- mutex_unlock(&sbi->wq_mutex);
- return err;
-}
-
-/*
- * Make the autofs mount point catatonic, no longer responsive to
- * mount requests. Also closes the kernel pipe file descriptor.
- */
-static int autofs_dev_ioctl_catatonic(struct file *fp,
- struct autofs_sb_info *sbi,
- struct autofs_dev_ioctl *param)
-{
- autofs_catatonic_mode(sbi);
- return 0;
-}
-
-/* Set the autofs mount timeout */
-static int autofs_dev_ioctl_timeout(struct file *fp,
- struct autofs_sb_info *sbi,
- struct autofs_dev_ioctl *param)
-{
- unsigned long timeout;
-
- timeout = param->timeout.timeout;
- param->timeout.timeout = sbi->exp_timeout / HZ;
- sbi->exp_timeout = timeout * HZ;
- return 0;
-}
-
-/*
- * Return the uid and gid of the last request for the mount
- *
- * When reconstructing an autofs mount tree with active mounts
- * we need to re-connect to mounts that may have used the original
- * process uid and gid (or string variations of them) for mount
- * lookups within the map entry.
- */
-static int autofs_dev_ioctl_requester(struct file *fp,
- struct autofs_sb_info *sbi,
- struct autofs_dev_ioctl *param)
-{
- struct autofs_info *ino;
- struct path path;
- dev_t devid;
- int err = -ENOENT;
-
- if (param->size <= AUTOFS_DEV_IOCTL_SIZE) {
- err = -EINVAL;
- goto out;
- }
-
- devid = sbi->sb->s_dev;
-
- param->requester.uid = param->requester.gid = -1;
-
- err = find_autofs_mount(param->path, &path, test_by_dev, &devid);
- if (err)
- goto out;
-
- ino = autofs_dentry_ino(path.dentry);
- if (ino) {
- err = 0;
- autofs_expire_wait(&path, 0);
- spin_lock(&sbi->fs_lock);
- param->requester.uid =
- from_kuid_munged(current_user_ns(), ino->uid);
- param->requester.gid =
- from_kgid_munged(current_user_ns(), ino->gid);
- spin_unlock(&sbi->fs_lock);
- }
- path_put(&path);
-out:
- return err;
-}
-
-/*
- * Call repeatedly until it returns -EAGAIN, meaning there's nothing
- * more that can be done.
- */
-static int autofs_dev_ioctl_expire(struct file *fp,
- struct autofs_sb_info *sbi,
- struct autofs_dev_ioctl *param)
-{
- struct vfsmount *mnt;
- int how;
-
- how = param->expire.how;
- mnt = fp->f_path.mnt;
-
- return autofs_do_expire_multi(sbi->sb, mnt, sbi, how);
-}
-
-/* Check if autofs mount point is in use */
-static int autofs_dev_ioctl_askumount(struct file *fp,
- struct autofs_sb_info *sbi,
- struct autofs_dev_ioctl *param)
-{
- param->askumount.may_umount = 0;
- if (may_umount(fp->f_path.mnt))
- param->askumount.may_umount = 1;
- return 0;
-}
-
-/*
- * Check if the given path is a mountpoint.
- *
- * If we are supplied with the file descriptor of an autofs
- * mount we're looking for a specific mount. In this case
- * the path is considered a mountpoint if it is itself a
- * mountpoint or contains a mount, such as a multi-mount
- * without a root mount. In this case we return 1 if the
- * path is a mount point and the super magic of the covering
- * mount if there is one or 0 if it isn't a mountpoint.
- *
- * If we aren't supplied with a file descriptor then we
- * lookup the path and check if it is the root of a mount.
- * If a type is given we are looking for a particular autofs
- * mount and if we don't find a match we return fail. If the
- * located path is the root of a mount we return 1 along with
- * the super magic of the mount or 0 otherwise.
- *
- * In both cases the the device number (as returned by
- * new_encode_dev()) is also returned.
- */
-static int autofs_dev_ioctl_ismountpoint(struct file *fp,
- struct autofs_sb_info *sbi,
- struct autofs_dev_ioctl *param)
-{
- struct path path;
- const char *name;
- unsigned int type;
- unsigned int devid, magic;
- int err = -ENOENT;
-
- if (param->size <= AUTOFS_DEV_IOCTL_SIZE) {
- err = -EINVAL;
- goto out;
- }
-
- name = param->path;
- type = param->ismountpoint.in.type;
-
- param->ismountpoint.out.devid = devid = 0;
- param->ismountpoint.out.magic = magic = 0;
-
- if (!fp || param->ioctlfd == -1) {
- if (autofs_type_any(type))
- err = kern_path_mountpoint(AT_FDCWD,
- name, &path, LOOKUP_FOLLOW);
- else
- err = find_autofs_mount(name, &path,
- test_by_type, &type);
- if (err)
- goto out;
- devid = new_encode_dev(path.dentry->d_sb->s_dev);
- err = 0;
- if (path.mnt->mnt_root == path.dentry) {
- err = 1;
- magic = path.dentry->d_sb->s_magic;
- }
- } else {
- dev_t dev = sbi->sb->s_dev;
-
- err = find_autofs_mount(name, &path, test_by_dev, &dev);
- if (err)
- goto out;
-
- devid = new_encode_dev(dev);
-
- err = path_has_submounts(&path);
-
- if (follow_down_one(&path))
- magic = path.dentry->d_sb->s_magic;
- }
-
- param->ismountpoint.out.devid = devid;
- param->ismountpoint.out.magic = magic;
- path_put(&path);
-out:
- return err;
-}
-
-/*
- * Our range of ioctl numbers isn't 0 based so we need to shift
- * the array index by _IOC_NR(AUTOFS_CTL_IOC_FIRST) for the table
- * lookup.
- */
-#define cmd_idx(cmd) (cmd - _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST))
-
-static ioctl_fn lookup_dev_ioctl(unsigned int cmd)
-{
- static ioctl_fn _ioctls[] = {
- autofs_dev_ioctl_version,
- autofs_dev_ioctl_protover,
- autofs_dev_ioctl_protosubver,
- autofs_dev_ioctl_openmount,
- autofs_dev_ioctl_closemount,
- autofs_dev_ioctl_ready,
- autofs_dev_ioctl_fail,
- autofs_dev_ioctl_setpipefd,
- autofs_dev_ioctl_catatonic,
- autofs_dev_ioctl_timeout,
- autofs_dev_ioctl_requester,
- autofs_dev_ioctl_expire,
- autofs_dev_ioctl_askumount,
- autofs_dev_ioctl_ismountpoint,
- };
- unsigned int idx = cmd_idx(cmd);
-
- return (idx >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[idx];
-}
-
-/* ioctl dispatcher */
-static int _autofs_dev_ioctl(unsigned int command,
- struct autofs_dev_ioctl __user *user)
-{
- struct autofs_dev_ioctl *param;
- struct file *fp;
- struct autofs_sb_info *sbi;
- unsigned int cmd_first, cmd;
- ioctl_fn fn = NULL;
- int err = 0;
-
- cmd_first = _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST);
- cmd = _IOC_NR(command);
-
- if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) ||
- cmd - cmd_first > AUTOFS_DEV_IOCTL_IOC_COUNT) {
- return -ENOTTY;
- }
-
- /* Only root can use ioctls other than AUTOFS_DEV_IOCTL_VERSION_CMD
- * and AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD
- */
- if (cmd != AUTOFS_DEV_IOCTL_VERSION_CMD &&
- cmd != AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD &&
- !capable(CAP_SYS_ADMIN))
- return -EPERM;
-
- /* Copy the parameters into kernel space. */
- param = copy_dev_ioctl(user);
- if (IS_ERR(param))
- return PTR_ERR(param);
-
- err = validate_dev_ioctl(command, param);
- if (err)
- goto out;
-
- fn = lookup_dev_ioctl(cmd);
- if (!fn) {
- pr_warn("unknown command 0x%08x\n", command);
- err = -ENOTTY;
- goto out;
- }
-
- fp = NULL;
- sbi = NULL;
-
- /*
- * For obvious reasons the openmount can't have a file
- * descriptor yet. We don't take a reference to the
- * file during close to allow for immediate release,
- * and the same for retrieving ioctl version.
- */
- if (cmd != AUTOFS_DEV_IOCTL_VERSION_CMD &&
- cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD &&
- cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) {
- fp = fget(param->ioctlfd);
- if (!fp) {
- if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD)
- goto cont;
- err = -EBADF;
- goto out;
- }
-
- sbi = autofs_dev_ioctl_sbi(fp);
- if (!sbi || sbi->magic != AUTOFS_SBI_MAGIC) {
- err = -EINVAL;
- fput(fp);
- goto out;
- }
-
- /*
- * Admin needs to be able to set the mount catatonic in
- * order to be able to perform the re-open.
- */
- if (!autofs_oz_mode(sbi) &&
- cmd != AUTOFS_DEV_IOCTL_CATATONIC_CMD) {
- err = -EACCES;
- fput(fp);
- goto out;
- }
- }
-cont:
- err = fn(fp, sbi, param);
-
- if (fp)
- fput(fp);
- if (err >= 0 && copy_to_user(user, param, AUTOFS_DEV_IOCTL_SIZE))
- err = -EFAULT;
-out:
- free_dev_ioctl(param);
- return err;
-}
-
-static long autofs_dev_ioctl(struct file *file, unsigned int command,
- unsigned long u)
-{
- int err;
-
- err = _autofs_dev_ioctl(command, (struct autofs_dev_ioctl __user *) u);
- return (long) err;
-}
-
-#ifdef CONFIG_COMPAT
-static long autofs_dev_ioctl_compat(struct file *file, unsigned int command,
- unsigned long u)
-{
- return autofs_dev_ioctl(file, command, (unsigned long) compat_ptr(u));
-}
-#else
-#define autofs_dev_ioctl_compat NULL
-#endif
-
-static const struct file_operations _dev_ioctl_fops = {
- .unlocked_ioctl = autofs_dev_ioctl,
- .compat_ioctl = autofs_dev_ioctl_compat,
- .owner = THIS_MODULE,
- .llseek = noop_llseek,
-};
-
-static struct miscdevice _autofs_dev_ioctl_misc = {
- .minor = AUTOFS_MINOR,
- .name = AUTOFS_DEVICE_NAME,
- .fops = &_dev_ioctl_fops,
- .mode = 0644,
-};
-
-MODULE_ALIAS_MISCDEV(AUTOFS_MINOR);
-MODULE_ALIAS("devname:autofs");
-
-/* Register/deregister misc character device */
-int __init autofs_dev_ioctl_init(void)
-{
- int r;
-
- r = misc_register(&_autofs_dev_ioctl_misc);
- if (r) {
- pr_err("misc_register failed for control device\n");
- return r;
- }
-
- return 0;
-}
-
-void autofs_dev_ioctl_exit(void)
-{
- misc_deregister(&_autofs_dev_ioctl_misc);
-}
projects / linux-2.6-block.git / blobdiff