Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted

Pull I3C updates from Alexandre Belloni:
 "A new driver this cycle, for the AMD AXI I3C controller.

  There are also new features such as IBI wakeup support, SETAASA device
  discovery and ACPI support for the the DAA methods, meaning we can now
  communicate with the SPD devices on DDR5 modules.

  New driver:
   - AMD AXI I3C master controller

  Subsystem:
   - I3C Common Command Code (CCC) handling improvements, especially
     around GET CCCs
   - SETAASA device discovery support
   - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
     well as I2C devices on I3C bus
   - IBI-based wakeup support

  Drivers:
   - dw: SETAASA support
   - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
     controller support, PIO queue management support for HCI v1.2
   - renesas: improve suspend to RAM support, add runtime PM support"

* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
  i3c: dw: reduce do_daa time if there's no client
  i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
  i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
  i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
  i3c: dw: rename "pclk" to "apb" to match dt-binding
  i3c: dw: make struct dw_i3c_cmd smaller
  i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
  i3c: renesas: Don't register devices when ENTDAA times out
  i3c: master: dw-i3c-master: fix OD timing for first broadcast
  i3c: mipi-i3c-hci: Advertise IBI wakeup capability
  i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
  i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
  i3c: master: Reject IBI requests from non-IBI-capable devices
  i3c: master: Add helper to query bus wakeup requirements
  i3c: master: Report wakeup events for IBIs
  i3c: master: Support IBI-based wakeup capability
  i3c: master: Fix potential UAF in i3c_device_match()
  i3c: master: Fix potential UAF in i3c_device_uevent()
  i3c: Make dev->desc locking assumptions explicit
  i3c: master: Fix use-after-free of master->this
  ...

1 files changed, 810 insertions, 0 deletions

diff --git a/fs/autofs/dev-ioctl.c b/fs/autofs/dev-ioctl.c
new file mode 100644
index 000000000..6743b3b64
--- /dev/null
+++ b/fs/autofs/dev-ioctl.c
@@ -0,0 +1,810 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2008 Red Hat, Inc. All rights reserved.
+ * Copyright 2008 Ian Kent <raven@themaw.net>
+ */
+
+#include <linux/module.h>
+#include <linux/miscdevice.h>
+#include <linux/compat.h>
+#include <linux/fdtable.h>
+#include <linux/magic.h>
+#include <linux/nospec.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 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)
+{
+	unsigned int inr = _IOC_NR(cmd);
+	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;
+		}
+
+		/* Setting the per-dentry expire timeout requires a trailing
+		 * path component, ie. no '/', so invert the logic of the
+		 * check_name() return for AUTOFS_DEV_IOCTL_TIMEOUT_CMD.
+		 */
+		err = check_name(param->path);
+		if (inr == AUTOFS_DEV_IOCTL_TIMEOUT_CMD)
+			err = err ? 0 : -EINVAL;
+		if (err) {
+			pr_warn("invalid path supplied for cmd(0x%08x)\n",
+				cmd);
+			goto out;
+		}
+	} else {
+		if (inr == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD ||
+		    inr == AUTOFS_DEV_IOCTL_REQUESTER_CMD ||
+		    inr == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) {
+			err = -EINVAL;
+			goto out;
+		}
+	}
+
+	err = 0;
+out:
+	return err;
+}
+
+/* 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(pathname, LOOKUP_MOUNTPOINT, &path);
+	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)
+{
+	struct path path __free(path_put) = {};
+	int err;
+
+	err = find_autofs_mount(name, &path, test_by_dev, &devid);
+	if (err)
+		return err;
+
+	return FD_ADD(O_CLOEXEC, dentry_open(&path, O_RDONLY, current_cred()));
+}
+
+/* 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 been checked in validate_dev_ioctl() */
+
+	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 close_fd(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->flags & AUTOFS_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->mnt_ns_id = to_ns_common(current->nsproxy->mnt_ns)->ns_id;
+		sbi->flags &= ~AUTOFS_SBI_CATATONIC;
+	}
+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 expire timeout.
+ *
+ * There are two places an expire timeout can be set, in the autofs
+ * super block info. (this is all that's needed for direct and offset
+ * mounts because there's a distinct mount corresponding to each of
+ * these) and per-dentry within within the dentry info. If a per-dentry
+ * timeout is set it will override the expire timeout set in the parent
+ * autofs super block info.
+ *
+ * If setting the autofs super block expire timeout the autofs_dev_ioctl
+ * size field will be equal to the autofs_dev_ioctl structure size. If
+ * setting the per-dentry expire timeout the mount point name is passed
+ * in the autofs_dev_ioctl path field and the size field updated to
+ * reflect this.
+ *
+ * Setting the autofs mount expire timeout sets the timeout in the super
+ * block info. struct. Setting the per-dentry timeout does a little more.
+ * If the timeout is equal to -1 the per-dentry timeout (and flag) is
+ * cleared which reverts to using the super block timeout, otherwise if
+ * timeout is 0 the timeout is set to this value and the flag is left
+ * set which disables expiration for the mount point, lastly the flag
+ * and the timeout are set enabling the dentry to use this timeout.
+ */
+static int autofs_dev_ioctl_timeout(struct file *fp,
+				    struct autofs_sb_info *sbi,
+				    struct autofs_dev_ioctl *param)
+{
+	unsigned long timeout = param->timeout.timeout;
+
+	/* If setting the expire timeout for an individual indirect
+	 * mount point dentry the mount trailing component path is
+	 * placed in param->path and param->size adjusted to account
+	 * for it otherwise param->size it is set to the structure
+	 * size.
+	 */
+	if (param->size == AUTOFS_DEV_IOCTL_SIZE) {
+		param->timeout.timeout = sbi->exp_timeout / HZ;
+		sbi->exp_timeout = timeout * HZ;
+	} else {
+		struct dentry *base = fp->f_path.dentry;
+		int path_len = param->size - AUTOFS_DEV_IOCTL_SIZE - 1;
+		struct dentry *dentry;
+		struct autofs_info *ino;
+
+		if (!autofs_type_indirect(sbi->type))
+			return -EINVAL;
+
+		dentry = try_lookup_noperm(&QSTR_LEN(param->path, path_len),
+					   base);
+		if (IS_ERR_OR_NULL(dentry))
+			return dentry ? PTR_ERR(dentry) : -ENOENT;
+		ino = autofs_dentry_ino(dentry);
+		if (!ino) {
+			dput(dentry);
+			return -ENOENT;
+		}
+
+		if (ino->exp_timeout && ino->flags & AUTOFS_INF_EXPIRE_SET)
+			param->timeout.timeout = ino->exp_timeout / HZ;
+		else
+			param->timeout.timeout = sbi->exp_timeout / HZ;
+
+		if (timeout == -1) {
+			/* Revert to using the super block timeout */
+			ino->flags &= ~AUTOFS_INF_EXPIRE_SET;
+			ino->exp_timeout = 0;
+		} else {
+			/* Set the dentry expire flag and timeout.
+			 *
+			 * If timeout is 0 it will prevent the expire
+			 * of this particular automount.
+			 */
+			ino->flags |= AUTOFS_INF_EXPIRE_SET;
+			ino->exp_timeout = timeout * HZ;
+		}
+
+		/* An expire timeout greater than the superblock timeout
+		 * could be a problem at shutdown but the super block
+		 * timeout itself can change so all we can really do is
+		 * warn the user.
+		 */
+		if (ino->flags & AUTOFS_INF_EXPIRE_SET &&
+		    ino->exp_timeout > sbi->exp_timeout)
+			pr_warn("per-mount expire timeout is greater than "
+				"the parent autofs mount timeout which could "
+				"prevent shutdown\n");
+
+		dput(dentry);
+	}
+
+	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;
+
+	/* param->path has been checked in validate_dev_ioctl() */
+
+	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 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;
+
+	/* param->path has been checked in validate_dev_ioctl() */
+
+	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(name, LOOKUP_FOLLOW | LOOKUP_MOUNTPOINT,
+					&path);
+		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 const 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);
+
+	if (idx >= ARRAY_SIZE(_ioctls))
+		return NULL;
+	idx = array_index_nospec(idx, ARRAY_SIZE(_ioctls));
+	return _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) {
+		struct super_block *sb;
+
+		fp = fget(param->ioctlfd);
+		if (!fp) {
+			if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD)
+				goto cont;
+			err = -EBADF;
+			goto out;
+		}
+
+		sb = file_inode(fp)->i_sb;
+		if (sb->s_type != &autofs_fs_type) {
+			err = -EINVAL;
+			fput(fp);
+			goto out;
+		}
+		sbi = autofs_sbi(sb);
+
+		/*
+		 * 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);
+}