[deliverable/linux.git] / fs / ecryptfs / miscdev.c

/**
 * eCryptfs: Linux filesystem encryption layer
 *
 * Copyright (C) 2008 International Business Machines Corp.
 *   Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 */

#include <linux/fs.h>
#include <linux/hash.h>
#include <linux/random.h>
#include <linux/miscdevice.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/wait.h>
#include <linux/module.h>
#include "ecryptfs_kernel.h"

static atomic_t ecryptfs_num_miscdev_opens;

/**
 * ecryptfs_miscdev_poll
 * @file: dev file (ignored)
 * @pt: dev poll table (ignored)
 *
 * Returns the poll mask
 */
static unsigned int
ecryptfs_miscdev_poll(struct file *file, poll_table *pt)
{
	struct ecryptfs_daemon *daemon;
	unsigned int mask = 0;
	uid_t euid = current_euid();
	int rc;

	mutex_lock(&ecryptfs_daemon_hash_mux);
	/* TODO: Just use file->private_data? */
	rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
	BUG_ON(rc || !daemon);
	mutex_lock(&daemon->mux);
	mutex_unlock(&ecryptfs_daemon_hash_mux);
	if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
		printk(KERN_WARNING "%s: Attempt to poll on zombified "
		       "daemon\n", __func__);
		goto out_unlock_daemon;
	}
	if (daemon->flags & ECRYPTFS_DAEMON_IN_READ)
		goto out_unlock_daemon;
	if (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)
		goto out_unlock_daemon;
	daemon->flags |= ECRYPTFS_DAEMON_IN_POLL;
	mutex_unlock(&daemon->mux);
	poll_wait(file, &daemon->wait, pt);
	mutex_lock(&daemon->mux);
	if (!list_empty(&daemon->msg_ctx_out_queue))
		mask |= POLLIN | POLLRDNORM;
out_unlock_daemon:
	daemon->flags &= ~ECRYPTFS_DAEMON_IN_POLL;
	mutex_unlock(&daemon->mux);
	return mask;
}

/**
 * ecryptfs_miscdev_open
 * @inode: inode of miscdev handle (ignored)
 * @file: file for miscdev handle (ignored)
 *
 * Returns zero on success; non-zero otherwise
 */
static int
ecryptfs_miscdev_open(struct inode *inode, struct file *file)
{
	struct ecryptfs_daemon *daemon = NULL;
	uid_t euid = current_euid();
	int rc;

	mutex_lock(&ecryptfs_daemon_hash_mux);
	rc = try_module_get(THIS_MODULE);
	if (rc == 0) {
		rc = -EIO;
		printk(KERN_ERR "%s: Error attempting to increment module use "
		       "count; rc = [%d]\n", __func__, rc);
		goto out_unlock_daemon_list;
	}
	rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
	if (rc || !daemon) {
		rc = ecryptfs_spawn_daemon(&daemon, euid, current_user_ns(),
					   task_pid(current));
		if (rc) {
			printk(KERN_ERR "%s: Error attempting to spawn daemon; "
			       "rc = [%d]\n", __func__, rc);
			goto out_module_put_unlock_daemon_list;
		}
	}
	mutex_lock(&daemon->mux);
	if (daemon->pid != task_pid(current)) {
		rc = -EINVAL;
		printk(KERN_ERR "%s: pid [0x%p] has registered with euid [%d], "
		       "but pid [0x%p] has attempted to open the handle "
		       "instead\n", __func__, daemon->pid, daemon->euid,
		       task_pid(current));
		goto out_unlock_daemon;
	}
	if (daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN) {
		rc = -EBUSY;
		printk(KERN_ERR "%s: Miscellaneous device handle may only be "
		       "opened once per daemon; pid [0x%p] already has this "
		       "handle open\n", __func__, daemon->pid);
		goto out_unlock_daemon;
	}
	daemon->flags |= ECRYPTFS_DAEMON_MISCDEV_OPEN;
	atomic_inc(&ecryptfs_num_miscdev_opens);
out_unlock_daemon:
	mutex_unlock(&daemon->mux);
out_module_put_unlock_daemon_list:
	if (rc)
		module_put(THIS_MODULE);
out_unlock_daemon_list:
	mutex_unlock(&ecryptfs_daemon_hash_mux);
	return rc;
}

/**
 * ecryptfs_miscdev_release
 * @inode: inode of fs/ecryptfs/euid handle (ignored)
 * @file: file for fs/ecryptfs/euid handle (ignored)
 *
 * This keeps the daemon registered until the daemon sends another
 * ioctl to fs/ecryptfs/ctl or until the kernel module unregisters.
 *
 * Returns zero on success; non-zero otherwise
 */
static int
ecryptfs_miscdev_release(struct inode *inode, struct file *file)
{
	struct ecryptfs_daemon *daemon = NULL;
	uid_t euid = current_euid();
	int rc;

	mutex_lock(&ecryptfs_daemon_hash_mux);
	rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
	BUG_ON(rc || !daemon);
	mutex_lock(&daemon->mux);
	BUG_ON(daemon->pid != task_pid(current));
	BUG_ON(!(daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN));
	daemon->flags &= ~ECRYPTFS_DAEMON_MISCDEV_OPEN;
	atomic_dec(&ecryptfs_num_miscdev_opens);
	mutex_unlock(&daemon->mux);
	rc = ecryptfs_exorcise_daemon(daemon);
	if (rc) {
		printk(KERN_CRIT "%s: Fatal error whilst attempting to "
		       "shut down daemon; rc = [%d]. Please report this "
		       "bug.\n", __func__, rc);
		BUG();
	}
	module_put(THIS_MODULE);
	mutex_unlock(&ecryptfs_daemon_hash_mux);
	return rc;
}

/**
 * ecryptfs_send_miscdev
 * @data: Data to send to daemon; may be NULL
 * @data_size: Amount of data to send to daemon
 * @msg_ctx: Message context, which is used to handle the reply. If
 *           this is NULL, then we do not expect a reply.
 * @msg_type: Type of message
 * @msg_flags: Flags for message
 * @daemon: eCryptfs daemon object
 *
 * Add msg_ctx to queue and then, if it exists, notify the blocked
 * miscdevess about the data being available. Must be called with
 * ecryptfs_daemon_hash_mux held.
 *
 * Returns zero on success; non-zero otherwise
 */
int ecryptfs_send_miscdev(char *data, size_t data_size,
			  struct ecryptfs_msg_ctx *msg_ctx, u8 msg_type,
			  u16 msg_flags, struct ecryptfs_daemon *daemon)
{
	int rc = 0;

	mutex_lock(&msg_ctx->mux);
	msg_ctx->msg = kmalloc((sizeof(*msg_ctx->msg) + data_size),
			       GFP_KERNEL);
	if (!msg_ctx->msg) {
		rc = -ENOMEM;
		printk(KERN_ERR "%s: Out of memory whilst attempting "
		       "to kmalloc(%zd, GFP_KERNEL)\n", __func__,
		       (sizeof(*msg_ctx->msg) + data_size));
		goto out_unlock;
	}
	msg_ctx->msg->index = msg_ctx->index;
	msg_ctx->msg->data_len = data_size;
	msg_ctx->type = msg_type;
	memcpy(msg_ctx->msg->data, data, data_size);
	msg_ctx->msg_size = (sizeof(*msg_ctx->msg) + data_size);
	mutex_lock(&daemon->mux);
	list_add_tail(&msg_ctx->daemon_out_list, &daemon->msg_ctx_out_queue);
	daemon->num_queued_msg_ctx++;
	wake_up_interruptible(&daemon->wait);
	mutex_unlock(&daemon->mux);
out_unlock:
	mutex_unlock(&msg_ctx->mux);
	return rc;
}

/*
 * miscdevfs packet format:
 *  Octet 0: Type
 *  Octets 1-4: network byte order msg_ctx->counter
 *  Octets 5-N0: Size of struct ecryptfs_message to follow
 *  Octets N0-N1: struct ecryptfs_message (including data)
 *
 *  Octets 5-N1 not written if the packet type does not include a message
 */
#define PKT_TYPE_SIZE		1
#define PKT_CTR_SIZE		4
#define MIN_NON_MSG_PKT_SIZE	(PKT_TYPE_SIZE + PKT_CTR_SIZE)
#define MIN_MSG_PKT_SIZE	(PKT_TYPE_SIZE + PKT_CTR_SIZE \
				 + ECRYPTFS_MIN_PKT_LEN_SIZE)
/* 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES comes from tag 65 packet format */
#define MAX_MSG_PKT_SIZE	(PKT_TYPE_SIZE + PKT_CTR_SIZE \
				 + ECRYPTFS_MAX_PKT_LEN_SIZE \
				 + sizeof(struct ecryptfs_message) \
				 + 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES)
#define PKT_TYPE_OFFSET		0
#define PKT_CTR_OFFSET		PKT_TYPE_SIZE
#define PKT_LEN_OFFSET		(PKT_TYPE_SIZE + PKT_CTR_SIZE)

/**
 * ecryptfs_miscdev_read - format and send message from queue
 * @file: fs/ecryptfs/euid miscdevfs handle (ignored)
 * @buf: User buffer into which to copy the next message on the daemon queue
 * @count: Amount of space available in @buf
 * @ppos: Offset in file (ignored)
 *
 * Pulls the most recent message from the daemon queue, formats it for
 * being sent via a miscdevfs handle, and copies it into @buf
 *
 * Returns the number of bytes copied into the user buffer
 */
static ssize_t
ecryptfs_miscdev_read(struct file *file, char __user *buf, size_t count,
		      loff_t *ppos)
{
	struct ecryptfs_daemon *daemon;
	struct ecryptfs_msg_ctx *msg_ctx;
	size_t packet_length_size;
	char packet_length[ECRYPTFS_MAX_PKT_LEN_SIZE];
	size_t i;
	size_t total_length;
	uid_t euid = current_euid();
	int rc;

	mutex_lock(&ecryptfs_daemon_hash_mux);
	/* TODO: Just use file->private_data? */
	rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
	BUG_ON(rc || !daemon);
	mutex_lock(&daemon->mux);
	if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
		rc = 0;
		mutex_unlock(&ecryptfs_daemon_hash_mux);
		printk(KERN_WARNING "%s: Attempt to read from zombified "
		       "daemon\n", __func__);
		goto out_unlock_daemon;
	}
	if (daemon->flags & ECRYPTFS_DAEMON_IN_READ) {
		rc = 0;
		mutex_unlock(&ecryptfs_daemon_hash_mux);
		goto out_unlock_daemon;
	}
	/* This daemon will not go away so long as this flag is set */
	daemon->flags |= ECRYPTFS_DAEMON_IN_READ;
	mutex_unlock(&ecryptfs_daemon_hash_mux);
check_list:
	if (list_empty(&daemon->msg_ctx_out_queue)) {
		mutex_unlock(&daemon->mux);
		rc = wait_event_interruptible(
			daemon->wait, !list_empty(&daemon->msg_ctx_out_queue));
		mutex_lock(&daemon->mux);
		if (rc < 0) {
			rc = 0;
			goto out_unlock_daemon;
		}
	}
	if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
		rc = 0;
		goto out_unlock_daemon;
	}
	if (list_empty(&daemon->msg_ctx_out_queue)) {
		/* Something else jumped in since the
		 * wait_event_interruptable() and removed the
		 * message from the queue; try again */
		goto check_list;
	}
	BUG_ON(euid != daemon->euid);
	BUG_ON(current_user_ns() != daemon->user_ns);
	BUG_ON(task_pid(current) != daemon->pid);
	msg_ctx = list_first_entry(&daemon->msg_ctx_out_queue,
				   struct ecryptfs_msg_ctx, daemon_out_list);
	BUG_ON(!msg_ctx);
	mutex_lock(&msg_ctx->mux);
	if (msg_ctx->msg) {
		rc = ecryptfs_write_packet_length(packet_length,
						  msg_ctx->msg_size,
						  &packet_length_size);
		if (rc) {
			rc = 0;
			printk(KERN_WARNING "%s: Error writing packet length; "
			       "rc = [%d]\n", __func__, rc);
			goto out_unlock_msg_ctx;
		}
	} else {
		packet_length_size = 0;
		msg_ctx->msg_size = 0;
	}
	total_length = (PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_length_size
			+ msg_ctx->msg_size);
	if (count < total_length) {
		rc = 0;
		printk(KERN_WARNING "%s: Only given user buffer of "
		       "size [%zd], but we need [%zd] to read the "
		       "pending message\n", __func__, count, total_length);
		goto out_unlock_msg_ctx;
	}
	rc = -EFAULT;
	if (put_user(msg_ctx->type, buf))
		goto out_unlock_msg_ctx;
	if (put_user(cpu_to_be32(msg_ctx->counter),
		     (__be32 __user *)(&buf[PKT_CTR_OFFSET])))
		goto out_unlock_msg_ctx;
	i = PKT_TYPE_SIZE + PKT_CTR_SIZE;
	if (msg_ctx->msg) {
		if (copy_to_user(&buf[i], packet_length, packet_length_size))
			goto out_unlock_msg_ctx;
		i += packet_length_size;
		if (copy_to_user(&buf[i], msg_ctx->msg, msg_ctx->msg_size))
			goto out_unlock_msg_ctx;
		i += msg_ctx->msg_size;
	}
	rc = i;
	list_del(&msg_ctx->daemon_out_list);
	kfree(msg_ctx->msg);
	msg_ctx->msg = NULL;
	/* We do not expect a reply from the userspace daemon for any
	 * message type other than ECRYPTFS_MSG_REQUEST */
	if (msg_ctx->type != ECRYPTFS_MSG_REQUEST)
		ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
out_unlock_msg_ctx:
	mutex_unlock(&msg_ctx->mux);
out_unlock_daemon:
	daemon->flags &= ~ECRYPTFS_DAEMON_IN_READ;
	mutex_unlock(&daemon->mux);
	return rc;
}

/**
 * ecryptfs_miscdev_response - miscdevess response to message previously sent to daemon
 * @data: Bytes comprising struct ecryptfs_message
 * @data_size: sizeof(struct ecryptfs_message) + data len
 * @euid: Effective user id of miscdevess sending the miscdev response
 * @user_ns: The namespace in which @euid applies
 * @pid: Miscdevess id of miscdevess sending the miscdev response
 * @seq: Sequence number for miscdev response packet
 *
 * Returns zero on success; non-zero otherwise
 */
static int ecryptfs_miscdev_response(char *data, size_t data_size,
				     uid_t euid, struct user_namespace *user_ns,
				     struct pid *pid, u32 seq)
{
	struct ecryptfs_message *msg = (struct ecryptfs_message *)data;
	int rc;

	if ((sizeof(*msg) + msg->data_len) != data_size) {
		printk(KERN_WARNING "%s: (sizeof(*msg) + msg->data_len) = "
		       "[%zd]; data_size = [%zd]. Invalid packet.\n", __func__,
		       (sizeof(*msg) + msg->data_len), data_size);
		rc = -EINVAL;
		goto out;
	}
	rc = ecryptfs_process_response(msg, euid, user_ns, pid, seq);
	if (rc)
		printk(KERN_ERR
		       "Error processing response message; rc = [%d]\n", rc);
out:
	return rc;
}

/**
 * ecryptfs_miscdev_write - handle write to daemon miscdev handle
 * @file: File for misc dev handle (ignored)
 * @buf: Buffer containing user data
 * @count: Amount of data in @buf
 * @ppos: Pointer to offset in file (ignored)
 *
 * Returns the number of bytes read from @buf
 */
static ssize_t
ecryptfs_miscdev_write(struct file *file, const char __user *buf,
		       size_t count, loff_t *ppos)
{
	__be32 counter_nbo;
	u32 seq;
	size_t packet_size, packet_size_length;
	char *data;
	uid_t euid = current_euid();
	unsigned char packet_size_peek[ECRYPTFS_MAX_PKT_LEN_SIZE];
	ssize_t rc;

	if (count == 0) {
		return 0;
	} else if (count == MIN_NON_MSG_PKT_SIZE) {
		/* Likely a harmless MSG_HELO or MSG_QUIT - no packet length */
		goto memdup;
	} else if (count < MIN_MSG_PKT_SIZE || count > MAX_MSG_PKT_SIZE) {
		printk(KERN_WARNING "%s: Acceptable packet size range is "
		       "[%d-%zu], but amount of data written is [%zu].",
		       __func__, MIN_MSG_PKT_SIZE, MAX_MSG_PKT_SIZE, count);
		return -EINVAL;
	}

	if (copy_from_user(packet_size_peek, &buf[PKT_LEN_OFFSET],
			   sizeof(packet_size_peek))) {
		printk(KERN_WARNING "%s: Error while inspecting packet size\n",
		       __func__);
		return -EFAULT;
	}

	rc = ecryptfs_parse_packet_length(packet_size_peek, &packet_size,
					  &packet_size_length);
	if (rc) {
		printk(KERN_WARNING "%s: Error parsing packet length; "
		       "rc = [%zd]\n", __func__, rc);
		return rc;
	}

	if ((PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_size_length + packet_size)
	    != count) {
		printk(KERN_WARNING "%s: Invalid packet size [%zu]\n", __func__,
		       packet_size);
		return -EINVAL;
	}

memdup:
	data = memdup_user(buf, count);
	if (IS_ERR(data)) {
		printk(KERN_ERR "%s: memdup_user returned error [%ld]\n",
		       __func__, PTR_ERR(data));
		return PTR_ERR(data);
	}
	switch (data[PKT_TYPE_OFFSET]) {
	case ECRYPTFS_MSG_RESPONSE:
		if (count < (MIN_MSG_PKT_SIZE
			     + sizeof(struct ecryptfs_message))) {
			printk(KERN_WARNING "%s: Minimum acceptable packet "
			       "size is [%zd], but amount of data written is "
			       "only [%zd]. Discarding response packet.\n",
			       __func__,
			       (MIN_MSG_PKT_SIZE
				+ sizeof(struct ecryptfs_message)), count);
			rc = -EINVAL;
			goto out_free;
		}
		memcpy(&counter_nbo, &data[PKT_CTR_OFFSET], PKT_CTR_SIZE);
		seq = be32_to_cpu(counter_nbo);
		rc = ecryptfs_miscdev_response(
				&data[PKT_LEN_OFFSET + packet_size_length],
				packet_size, euid, current_user_ns(),
				task_pid(current), seq);
		if (rc) {
			printk(KERN_WARNING "%s: Failed to deliver miscdev "
			       "response to requesting operation; rc = [%zd]\n",
			       __func__, rc);
			goto out_free;
		}
		break;
	case ECRYPTFS_MSG_HELO:
	case ECRYPTFS_MSG_QUIT:
		break;
	default:
		ecryptfs_printk(KERN_WARNING, "Dropping miscdev "
				"message of unrecognized type [%d]\n",
				data[0]);
		rc = -EINVAL;
		goto out_free;
	}
	rc = count;
out_free:
	kfree(data);
	return rc;
}


static const struct file_operations ecryptfs_miscdev_fops = {
	.open    = ecryptfs_miscdev_open,
	.poll    = ecryptfs_miscdev_poll,
	.read    = ecryptfs_miscdev_read,
	.write   = ecryptfs_miscdev_write,
	.release = ecryptfs_miscdev_release,
	.llseek  = noop_llseek,
};

static struct miscdevice ecryptfs_miscdev = {
	.minor = MISC_DYNAMIC_MINOR,
	.name  = "ecryptfs",
	.fops  = &ecryptfs_miscdev_fops
};

/**
 * ecryptfs_init_ecryptfs_miscdev
 *
 * Messages sent to the userspace daemon from the kernel are placed on
 * a queue associated with the daemon. The next read against the
 * miscdev handle by that daemon will return the oldest message placed
 * on the message queue for the daemon.
 *
 * Returns zero on success; non-zero otherwise
 */
int __init ecryptfs_init_ecryptfs_miscdev(void)
{
	int rc;

	atomic_set(&ecryptfs_num_miscdev_opens, 0);
	rc = misc_register(&ecryptfs_miscdev);
	if (rc)
		printk(KERN_ERR "%s: Failed to register miscellaneous device "
		       "for communications with userspace daemons; rc = [%d]\n",
		       __func__, rc);
	return rc;
}

/**
 * ecryptfs_destroy_ecryptfs_miscdev
 *
 * All of the daemons must be exorcised prior to calling this
 * function.
 */
void ecryptfs_destroy_ecryptfs_miscdev(void)
{
	BUG_ON(atomic_read(&ecryptfs_num_miscdev_opens) != 0);
	misc_deregister(&ecryptfs_miscdev);
}
Commit	Line	Data
8bf2debd MH	1	/**
	2	* eCryptfs: Linux filesystem encryption layer
	3	*
	4	* Copyright (C) 2008 International Business Machines Corp.
	5	* Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
	6	*
	7	* This program is free software; you can redistribute it and/or
	8	* modify it under the terms of the GNU General Public License version
	9	* 2 as published by the Free Software Foundation.
	10	*
	11	* This program is distributed in the hope that it will be useful, but
	12	* WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	14	* General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
	19	* 02111-1307, USA.
	20	*/
	21
	22	#include <linux/fs.h>
	23	#include <linux/hash.h>
	24	#include <linux/random.h>
	25	#include <linux/miscdevice.h>
	26	#include <linux/poll.h>
5a0e3ad6	27	#include <linux/slab.h>
8bf2debd MH	28	#include <linux/wait.h>
	29	#include <linux/module.h>
	30	#include "ecryptfs_kernel.h"
	31
	32	static atomic_t ecryptfs_num_miscdev_opens;
	33
	34	/**
	35	* ecryptfs_miscdev_poll
	36	* @file: dev file (ignored)
	37	* @pt: dev poll table (ignored)
	38	*
	39	* Returns the poll mask
	40	*/
	41	static unsigned int
	42	ecryptfs_miscdev_poll(struct file file, poll_table pt)
	43	{
	44	struct ecryptfs_daemon *daemon;
	45	unsigned int mask = 0;
4eea0353	46	uid_t euid = current_euid();
8bf2debd MH	47	int rc;
	48
	49	mutex_lock(&ecryptfs_daemon_hash_mux);
	50	/* TODO: Just use file->private_data? */
18b6e041	51	rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
8bf2debd MH	52	BUG_ON(rc \|\| !daemon);
	53	mutex_lock(&daemon->mux);
	54	mutex_unlock(&ecryptfs_daemon_hash_mux);
	55	if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
	56	printk(KERN_WARNING "%s: Attempt to poll on zombified "
	57	"daemon\n", __func__);
	58	goto out_unlock_daemon;
	59	}
	60	if (daemon->flags & ECRYPTFS_DAEMON_IN_READ)
	61	goto out_unlock_daemon;
	62	if (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)
	63	goto out_unlock_daemon;
	64	daemon->flags \|= ECRYPTFS_DAEMON_IN_POLL;
	65	mutex_unlock(&daemon->mux);
	66	poll_wait(file, &daemon->wait, pt);
	67	mutex_lock(&daemon->mux);
	68	if (!list_empty(&daemon->msg_ctx_out_queue))
	69	mask \|= POLLIN \| POLLRDNORM;
	70	out_unlock_daemon:
	71	daemon->flags &= ~ECRYPTFS_DAEMON_IN_POLL;
	72	mutex_unlock(&daemon->mux);
	73	return mask;
	74	}
	75
	76	/**
	77	* ecryptfs_miscdev_open
	78	* @inode: inode of miscdev handle (ignored)
	79	* @file: file for miscdev handle (ignored)
	80	*
	81	* Returns zero on success; non-zero otherwise
	82	*/
	83	static int
	84	ecryptfs_miscdev_open(struct inode inode, struct file file)
	85	{
	86	struct ecryptfs_daemon *daemon = NULL;
4eea0353	87	uid_t euid = current_euid();
8bf2debd MH	88	int rc;
	89
	90	mutex_lock(&ecryptfs_daemon_hash_mux);
	91	rc = try_module_get(THIS_MODULE);
	92	if (rc == 0) {
	93	rc = -EIO;
	94	printk(KERN_ERR "%s: Error attempting to increment module use "
	95	"count; rc = [%d]\n", __func__, rc);
	96	goto out_unlock_daemon_list;
	97	}
18b6e041	98	rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
8bf2debd	99	if (rc \|\| !daemon) {
18b6e041	100	rc = ecryptfs_spawn_daemon(&daemon, euid, current_user_ns(),
6a3fd92e	101	task_pid(current));
8bf2debd MH	102	if (rc) {
	103	printk(KERN_ERR "%s: Error attempting to spawn daemon; "
	104	"rc = [%d]\n", __func__, rc);
	105	goto out_module_put_unlock_daemon_list;
	106	}
	107	}
	108	mutex_lock(&daemon->mux);
6a3fd92e	109	if (daemon->pid != task_pid(current)) {
8bf2debd	110	rc = -EINVAL;
6a3fd92e MH	111	printk(KERN_ERR "%s: pid [0x%p] has registered with euid [%d], "
6a3fd92e MH	112	"but pid [0x%p] has attempted to open the handle "
8bf2debd	113	"instead\n", __func__, daemon->pid, daemon->euid,
6a3fd92e	114	task_pid(current));
8bf2debd MH	115	goto out_unlock_daemon;
	116	}
	117	if (daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN) {
	118	rc = -EBUSY;
	119	printk(KERN_ERR "%s: Miscellaneous device handle may only be "
6a3fd92e	120	"opened once per daemon; pid [0x%p] already has this "
8bf2debd MH	121	"handle open\n", __func__, daemon->pid);
	122	goto out_unlock_daemon;
	123	}
	124	daemon->flags \|= ECRYPTFS_DAEMON_MISCDEV_OPEN;
	125	atomic_inc(&ecryptfs_num_miscdev_opens);
	126	out_unlock_daemon:
	127	mutex_unlock(&daemon->mux);
	128	out_module_put_unlock_daemon_list:
	129	if (rc)
	130	module_put(THIS_MODULE);
	131	out_unlock_daemon_list:
	132	mutex_unlock(&ecryptfs_daemon_hash_mux);
	133	return rc;
	134	}
	135
	136	/**
	137	* ecryptfs_miscdev_release
	138	* @inode: inode of fs/ecryptfs/euid handle (ignored)
	139	* @file: file for fs/ecryptfs/euid handle (ignored)
	140	*
	141	* This keeps the daemon registered until the daemon sends another
	142	* ioctl to fs/ecryptfs/ctl or until the kernel module unregisters.
	143	*
	144	* Returns zero on success; non-zero otherwise
	145	*/
	146	static int
	147	ecryptfs_miscdev_release(struct inode inode, struct file file)
	148	{
	149	struct ecryptfs_daemon *daemon = NULL;
4eea0353	150	uid_t euid = current_euid();
8bf2debd MH	151	int rc;
	152
	153	mutex_lock(&ecryptfs_daemon_hash_mux);
18b6e041	154	rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
8bf2debd MH	155	BUG_ON(rc \|\| !daemon);
8bf2debd MH	156	mutex_lock(&daemon->mux);
6a3fd92e	157	BUG_ON(daemon->pid != task_pid(current));
8bf2debd MH	158	BUG_ON(!(daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN));
	159	daemon->flags &= ~ECRYPTFS_DAEMON_MISCDEV_OPEN;
	160	atomic_dec(&ecryptfs_num_miscdev_opens);
	161	mutex_unlock(&daemon->mux);
	162	rc = ecryptfs_exorcise_daemon(daemon);
	163	if (rc) {
	164	printk(KERN_CRIT "%s: Fatal error whilst attempting to "
	165	"shut down daemon; rc = [%d]. Please report this "
	166	"bug.\n", __func__, rc);
	167	BUG();
	168	}
	169	module_put(THIS_MODULE);
	170	mutex_unlock(&ecryptfs_daemon_hash_mux);
	171	return rc;
	172	}
	173
	174	/**
	175	* ecryptfs_send_miscdev
	176	* @data: Data to send to daemon; may be NULL
	177	* @data_size: Amount of data to send to daemon
	178	* @msg_ctx: Message context, which is used to handle the reply. If
	179	* this is NULL, then we do not expect a reply.
	180	* @msg_type: Type of message
	181	* @msg_flags: Flags for message
	182	* @daemon: eCryptfs daemon object
	183	*
	184	* Add msg_ctx to queue and then, if it exists, notify the blocked
	185	* miscdevess about the data being available. Must be called with
	186	* ecryptfs_daemon_hash_mux held.
	187	*
	188	* Returns zero on success; non-zero otherwise
	189	*/
	190	int ecryptfs_send_miscdev(char *data, size_t data_size,
	191	struct ecryptfs_msg_ctx *msg_ctx, u8 msg_type,
	192	u16 msg_flags, struct ecryptfs_daemon *daemon)
	193	{
	194	int rc = 0;
	195
	196	mutex_lock(&msg_ctx->mux);
57ea34d1 TH	197	msg_ctx->msg = kmalloc((sizeof(*msg_ctx->msg) + data_size),
	198	GFP_KERNEL);
	199	if (!msg_ctx->msg) {
	200	rc = -ENOMEM;
	201	printk(KERN_ERR "%s: Out of memory whilst attempting "
	202	"to kmalloc(%zd, GFP_KERNEL)\n", __func__,
	203	(sizeof(*msg_ctx->msg) + data_size));
	204	goto out_unlock;
	205	}
8bf2debd MH	206	msg_ctx->msg->index = msg_ctx->index;
	207	msg_ctx->msg->data_len = data_size;
	208	msg_ctx->type = msg_type;
57ea34d1 TH	209	memcpy(msg_ctx->msg->data, data, data_size);
57ea34d1 TH	210	msg_ctx->msg_size = (sizeof(*msg_ctx->msg) + data_size);
8bf2debd MH	211	mutex_lock(&daemon->mux);
	212	list_add_tail(&msg_ctx->daemon_out_list, &daemon->msg_ctx_out_queue);
	213	daemon->num_queued_msg_ctx++;
	214	wake_up_interruptible(&daemon->wait);
	215	mutex_unlock(&daemon->mux);
	216	out_unlock:
	217	mutex_unlock(&msg_ctx->mux);
	218	return rc;
	219	}
	220
48399c0b TH	221	/*
	222	* miscdevfs packet format:
	223	* Octet 0: Type
	224	* Octets 1-4: network byte order msg_ctx->counter
	225	* Octets 5-N0: Size of struct ecryptfs_message to follow
	226	* Octets N0-N1: struct ecryptfs_message (including data)
	227	*
	228	* Octets 5-N1 not written if the packet type does not include a message
	229	*/
	230	#define PKT_TYPE_SIZE 1
	231	#define PKT_CTR_SIZE 4
	232	#define MIN_NON_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE)
	233	#define MIN_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE \
	234	+ ECRYPTFS_MIN_PKT_LEN_SIZE)
	235	/* 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES comes from tag 65 packet format */
	236	#define MAX_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE \
	237	+ ECRYPTFS_MAX_PKT_LEN_SIZE \
	238	+ sizeof(struct ecryptfs_message) \
	239	+ 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES)
	240	#define PKT_TYPE_OFFSET 0
	241	#define PKT_CTR_OFFSET PKT_TYPE_SIZE
	242	#define PKT_LEN_OFFSET (PKT_TYPE_SIZE + PKT_CTR_SIZE)
	243
8bf2debd MH	244	/**
	245	* ecryptfs_miscdev_read - format and send message from queue
	246	* @file: fs/ecryptfs/euid miscdevfs handle (ignored)
	247	* @buf: User buffer into which to copy the next message on the daemon queue
	248	* @count: Amount of space available in @buf
	249	* @ppos: Offset in file (ignored)
	250	*
	251	* Pulls the most recent message from the daemon queue, formats it for
	252	* being sent via a miscdevfs handle, and copies it into @buf
	253	*
	254	* Returns the number of bytes copied into the user buffer
	255	*/
f66e883e	256	static ssize_t
8bf2debd MH	257	ecryptfs_miscdev_read(struct file file, char __user buf, size_t count,
	258	loff_t *ppos)
	259	{
	260	struct ecryptfs_daemon *daemon;
	261	struct ecryptfs_msg_ctx *msg_ctx;
	262	size_t packet_length_size;
48399c0b	263	char packet_length[ECRYPTFS_MAX_PKT_LEN_SIZE];
8bf2debd MH	264	size_t i;
8bf2debd MH	265	size_t total_length;
4eea0353	266	uid_t euid = current_euid();
8bf2debd MH	267	int rc;
	268
	269	mutex_lock(&ecryptfs_daemon_hash_mux);
	270	/* TODO: Just use file->private_data? */
18b6e041	271	rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
8bf2debd MH	272	BUG_ON(rc \|\| !daemon);
	273	mutex_lock(&daemon->mux);
	274	if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
	275	rc = 0;
43f14d85	276	mutex_unlock(&ecryptfs_daemon_hash_mux);
8bf2debd MH	277	printk(KERN_WARNING "%s: Attempt to read from zombified "
	278	"daemon\n", __func__);
	279	goto out_unlock_daemon;
	280	}
	281	if (daemon->flags & ECRYPTFS_DAEMON_IN_READ) {
	282	rc = 0;
43f14d85	283	mutex_unlock(&ecryptfs_daemon_hash_mux);
8bf2debd MH	284	goto out_unlock_daemon;
	285	}
	286	/* This daemon will not go away so long as this flag is set */
	287	daemon->flags \|= ECRYPTFS_DAEMON_IN_READ;
	288	mutex_unlock(&ecryptfs_daemon_hash_mux);
	289	check_list:
	290	if (list_empty(&daemon->msg_ctx_out_queue)) {
	291	mutex_unlock(&daemon->mux);
	292	rc = wait_event_interruptible(
	293	daemon->wait, !list_empty(&daemon->msg_ctx_out_queue));
	294	mutex_lock(&daemon->mux);
	295	if (rc < 0) {
	296	rc = 0;
	297	goto out_unlock_daemon;
	298	}
	299	}
	300	if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
	301	rc = 0;
	302	goto out_unlock_daemon;
	303	}
	304	if (list_empty(&daemon->msg_ctx_out_queue)) {
	305	/* Something else jumped in since the
	306	* wait_event_interruptable() and removed the
	307	* message from the queue; try again */
	308	goto check_list;
	309	}
4eea0353	310	BUG_ON(euid != daemon->euid);
18b6e041	311	BUG_ON(current_user_ns() != daemon->user_ns);
6a3fd92e	312	BUG_ON(task_pid(current) != daemon->pid);
8bf2debd MH	313	msg_ctx = list_first_entry(&daemon->msg_ctx_out_queue,
	314	struct ecryptfs_msg_ctx, daemon_out_list);
	315	BUG_ON(!msg_ctx);
	316	mutex_lock(&msg_ctx->mux);
	317	if (msg_ctx->msg) {
	318	rc = ecryptfs_write_packet_length(packet_length,
	319	msg_ctx->msg_size,
	320	&packet_length_size);
	321	if (rc) {
	322	rc = 0;
	323	printk(KERN_WARNING "%s: Error writing packet length; "
	324	"rc = [%d]\n", __func__, rc);
	325	goto out_unlock_msg_ctx;
	326	}
	327	} else {
	328	packet_length_size = 0;
	329	msg_ctx->msg_size = 0;
	330	}
48399c0b TH	331	total_length = (PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_length_size
48399c0b TH	332	+ msg_ctx->msg_size);
8bf2debd MH	333	if (count < total_length) {
	334	rc = 0;
	335	printk(KERN_WARNING "%s: Only given user buffer of "
df261c52	336	"size [%zd], but we need [%zd] to read the "
8bf2debd MH	337	"pending message\n", __func__, count, total_length);
	338	goto out_unlock_msg_ctx;
	339	}
79bc12a0 AV	340	rc = -EFAULT;
	341	if (put_user(msg_ctx->type, buf))
	342	goto out_unlock_msg_ctx;
48399c0b TH	343	if (put_user(cpu_to_be32(msg_ctx->counter),
48399c0b TH	344	(__be32 __user *)(&buf[PKT_CTR_OFFSET])))
79bc12a0	345	goto out_unlock_msg_ctx;
48399c0b	346	i = PKT_TYPE_SIZE + PKT_CTR_SIZE;
8bf2debd	347	if (msg_ctx->msg) {
79bc12a0 AV	348	if (copy_to_user(&buf[i], packet_length, packet_length_size))
79bc12a0 AV	349	goto out_unlock_msg_ctx;
8bf2debd	350	i += packet_length_size;
79bc12a0	351	if (copy_to_user(&buf[i], msg_ctx->msg, msg_ctx->msg_size))
8bf2debd	352	goto out_unlock_msg_ctx;
8bf2debd MH	353	i += msg_ctx->msg_size;
	354	}
	355	rc = i;
	356	list_del(&msg_ctx->daemon_out_list);
	357	kfree(msg_ctx->msg);
	358	msg_ctx->msg = NULL;
	359	/* We do not expect a reply from the userspace daemon for any
	360	* message type other than ECRYPTFS_MSG_REQUEST */
	361	if (msg_ctx->type != ECRYPTFS_MSG_REQUEST)
	362	ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
	363	out_unlock_msg_ctx:
	364	mutex_unlock(&msg_ctx->mux);
	365	out_unlock_daemon:
	366	daemon->flags &= ~ECRYPTFS_DAEMON_IN_READ;
	367	mutex_unlock(&daemon->mux);
	368	return rc;
	369	}
	370
8bf2debd MH	371	/**
	372	* ecryptfs_miscdev_response - miscdevess response to message previously sent to daemon
	373	* @data: Bytes comprising struct ecryptfs_message
	374	* @data_size: sizeof(struct ecryptfs_message) + data len
	375	* @euid: Effective user id of miscdevess sending the miscdev response
6a3fd92e	376	* @user_ns: The namespace in which @euid applies
8bf2debd MH	377	* @pid: Miscdevess id of miscdevess sending the miscdev response
	378	* @seq: Sequence number for miscdev response packet
	379	*
	380	* Returns zero on success; non-zero otherwise
	381	*/
	382	static int ecryptfs_miscdev_response(char *data, size_t data_size,
6a3fd92e MH	383	uid_t euid, struct user_namespace *user_ns,
6a3fd92e MH	384	struct pid *pid, u32 seq)
8bf2debd MH	385	{
	386	struct ecryptfs_message msg = (struct ecryptfs_message )data;
	387	int rc;
	388
	389	if ((sizeof(*msg) + msg->data_len) != data_size) {
	390	printk(KERN_WARNING "%s: (sizeof(*msg) + msg->data_len) = "
df261c52	391	"[%zd]; data_size = [%zd]. Invalid packet.\n", __func__,
8bf2debd MH	392	(sizeof(*msg) + msg->data_len), data_size);
	393	rc = -EINVAL;
	394	goto out;
	395	}
6a3fd92e	396	rc = ecryptfs_process_response(msg, euid, user_ns, pid, seq);
8bf2debd MH	397	if (rc)
	398	printk(KERN_ERR
	399	"Error processing response message; rc = [%d]\n", rc);
	400	out:
	401	return rc;
	402	}
	403
	404	/**
	405	* ecryptfs_miscdev_write - handle write to daemon miscdev handle
	406	* @file: File for misc dev handle (ignored)
	407	* @buf: Buffer containing user data
	408	* @count: Amount of data in @buf
	409	* @ppos: Pointer to offset in file (ignored)
	410	*
8bf2debd MH	411	* Returns the number of bytes read from @buf
	412	*/
	413	static ssize_t
	414	ecryptfs_miscdev_write(struct file file, const char __user buf,
	415	size_t count, loff_t *ppos)
	416	{
79bc12a0 AV	417	__be32 counter_nbo;
79bc12a0 AV	418	u32 seq;
48399c0b	419	size_t packet_size, packet_size_length;
8bf2debd	420	char *data;
4eea0353	421	uid_t euid = current_euid();
48399c0b	422	unsigned char packet_size_peek[ECRYPTFS_MAX_PKT_LEN_SIZE];
7f133504	423	ssize_t rc;
8bf2debd	424
db10e556	425	if (count == 0) {
7f133504	426	return 0;
48399c0b	427	} else if (count == MIN_NON_MSG_PKT_SIZE) {
db10e556 TH	428	/* Likely a harmless MSG_HELO or MSG_QUIT - no packet length */
db10e556 TH	429	goto memdup;
48399c0b	430	} else if (count < MIN_MSG_PKT_SIZE \|\| count > MAX_MSG_PKT_SIZE) {
db10e556	431	printk(KERN_WARNING "%s: Acceptable packet size range is "
164974a8	432	"[%d-%zu], but amount of data written is [%zu].",
48399c0b	433	__func__, MIN_MSG_PKT_SIZE, MAX_MSG_PKT_SIZE, count);
db10e556 TH	434	return -EINVAL;
	435	}
	436
48399c0b	437	if (copy_from_user(packet_size_peek, &buf[PKT_LEN_OFFSET],
db10e556 TH	438	sizeof(packet_size_peek))) {
	439	printk(KERN_WARNING "%s: Error while inspecting packet size\n",
	440	__func__);
	441	return -EFAULT;
	442	}
	443
	444	rc = ecryptfs_parse_packet_length(packet_size_peek, &packet_size,
	445	&packet_size_length);
	446	if (rc) {
	447	printk(KERN_WARNING "%s: Error parsing packet length; "
7f133504	448	"rc = [%zd]\n", __func__, rc);
db10e556 TH	449	return rc;
	450	}
	451
48399c0b TH	452	if ((PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_size_length + packet_size)
48399c0b TH	453	!= count) {
db10e556 TH	454	printk(KERN_WARNING "%s: Invalid packet size [%zu]\n", __func__,
	455	packet_size);
	456	return -EINVAL;
	457	}
fd56d242	458
db10e556	459	memdup:
fd56d242 LZ	460	data = memdup_user(buf, count);
	461	if (IS_ERR(data)) {
	462	printk(KERN_ERR "%s: memdup_user returned error [%ld]\n",
	463	__func__, PTR_ERR(data));
7f133504	464	return PTR_ERR(data);
8bf2debd	465	}
48399c0b	466	switch (data[PKT_TYPE_OFFSET]) {
8bf2debd	467	case ECRYPTFS_MSG_RESPONSE:
48399c0b TH	468	if (count < (MIN_MSG_PKT_SIZE
48399c0b TH	469	+ sizeof(struct ecryptfs_message))) {
8bf2debd	470	printk(KERN_WARNING "%s: Minimum acceptable packet "
df261c52 MH	471	"size is [%zd], but amount of data written is "
df261c52 MH	472	"only [%zd]. Discarding response packet.\n",
8bf2debd	473	__func__,
48399c0b TH	474	(MIN_MSG_PKT_SIZE
48399c0b TH	475	+ sizeof(struct ecryptfs_message)), count);
7f133504	476	rc = -EINVAL;
8bf2debd MH	477	goto out_free;
8bf2debd MH	478	}
48399c0b	479	memcpy(&counter_nbo, &data[PKT_CTR_OFFSET], PKT_CTR_SIZE);
8bf2debd	480	seq = be32_to_cpu(counter_nbo);
48399c0b TH	481	rc = ecryptfs_miscdev_response(
	482	&data[PKT_LEN_OFFSET + packet_size_length],
	483	packet_size, euid, current_user_ns(),
	484	task_pid(current), seq);
7f133504	485	if (rc) {
8bf2debd	486	printk(KERN_WARNING "%s: Failed to deliver miscdev "
7f133504	487	"response to requesting operation; rc = [%zd]\n",
8bf2debd	488	__func__, rc);
7f133504 TH	489	goto out_free;
7f133504 TH	490	}
8bf2debd MH	491	break;
8bf2debd MH	492	case ECRYPTFS_MSG_HELO:
8bf2debd	493	case ECRYPTFS_MSG_QUIT:
8bf2debd MH	494	break;
	495	default:
	496	ecryptfs_printk(KERN_WARNING, "Dropping miscdev "
	497	"message of unrecognized type [%d]\n",
	498	data[0]);
7f133504 TH	499	rc = -EINVAL;
7f133504 TH	500	goto out_free;
8bf2debd	501	}
7f133504	502	rc = count;
8bf2debd MH	503	out_free:
8bf2debd MH	504	kfree(data);
7f133504	505	return rc;
8bf2debd MH	506	}
	507
	508
	509	static const struct file_operations ecryptfs_miscdev_fops = {
	510	.open = ecryptfs_miscdev_open,
	511	.poll = ecryptfs_miscdev_poll,
	512	.read = ecryptfs_miscdev_read,
	513	.write = ecryptfs_miscdev_write,
	514	.release = ecryptfs_miscdev_release,
6038f373	515	.llseek = noop_llseek,
8bf2debd MH	516	};
	517
	518	static struct miscdevice ecryptfs_miscdev = {
	519	.minor = MISC_DYNAMIC_MINOR,
	520	.name = "ecryptfs",
	521	.fops = &ecryptfs_miscdev_fops
	522	};
	523
	524	/**
	525	* ecryptfs_init_ecryptfs_miscdev
	526	*
	527	* Messages sent to the userspace daemon from the kernel are placed on
	528	* a queue associated with the daemon. The next read against the
	529	* miscdev handle by that daemon will return the oldest message placed
	530	* on the message queue for the daemon.
	531	*
	532	* Returns zero on success; non-zero otherwise
	533	*/
7371a382	534	int __init ecryptfs_init_ecryptfs_miscdev(void)
8bf2debd MH	535	{
	536	int rc;
	537
	538	atomic_set(&ecryptfs_num_miscdev_opens, 0);
8bf2debd MH	539	rc = misc_register(&ecryptfs_miscdev);
	540	if (rc)
	541	printk(KERN_ERR "%s: Failed to register miscellaneous device "
	542	"for communications with userspace daemons; rc = [%d]\n",
	543	__func__, rc);
8bf2debd MH	544	return rc;
	545	}
	546
	547	/**
	548	* ecryptfs_destroy_ecryptfs_miscdev
	549	*
	550	* All of the daemons must be exorcised prior to calling this
	551	* function.
	552	*/
	553	void ecryptfs_destroy_ecryptfs_miscdev(void)
	554	{
	555	BUG_ON(atomic_read(&ecryptfs_num_miscdev_opens) != 0);
	556	misc_deregister(&ecryptfs_miscdev);
	557	}