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

/**
 * eCryptfs: Linux filesystem encryption layer
 *
 * Copyright (C) 2008 International Business Machines Corp.
 *   Author(s): Michael A. Halcrow <[email protected]>
 *
 * 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
 * @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 = file->private_data;
	unsigned int mask = 0;

	mutex_lock(&daemon->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
 *
 * Returns zero on success; non-zero otherwise
 */
static int
ecryptfs_miscdev_open(struct inode *inode, struct file *file)
{
	struct ecryptfs_daemon *daemon = NULL;
	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);
	if (!rc) {
		rc = -EINVAL;
		goto out_unlock_daemon_list;
	}
	rc = ecryptfs_spawn_daemon(&daemon, file);
	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->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN) {
		rc = -EBUSY;
		goto out_unlock_daemon;
	}
	daemon->flags |= ECRYPTFS_DAEMON_MISCDEV_OPEN;
	file->private_data = daemon;
	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
 *
 * 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 = file->private_data;
	int rc;

	mutex_lock(&daemon->mux);
	BUG_ON(!(daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN));
	daemon->flags &= ~ECRYPTFS_DAEMON_MISCDEV_OPEN;
	atomic_dec(&ecryptfs_num_miscdev_opens);
	mutex_unlock(&daemon->mux);

	mutex_lock(&ecryptfs_daemon_hash_mux);
	rc = ecryptfs_exorcise_daemon(daemon);
	mutex_unlock(&ecryptfs_daemon_hash_mux);
	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);
	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)
{
	struct ecryptfs_message *msg;

	msg = kmalloc((sizeof(*msg) + data_size), GFP_KERNEL);
	if (!msg) {
		printk(KERN_ERR "%s: Out of memory whilst attempting "
		       "to kmalloc(%zd, GFP_KERNEL)\n", __func__,
		       (sizeof(*msg) + data_size));
		return -ENOMEM;
	}

	mutex_lock(&msg_ctx->mux);
	msg_ctx->msg = msg;
	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);
	list_add_tail(&msg_ctx->daemon_out_list, &daemon->msg_ctx_out_queue);
	mutex_unlock(&msg_ctx->mux);

	mutex_lock(&daemon->mux);
	daemon->num_queued_msg_ctx++;
	wake_up_interruptible(&daemon->wait);
	mutex_unlock(&daemon->mux);

	return 0;
}

/*
 * 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: miscdevfs handle
 * @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 = file->private_data;
	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;
	int rc;

	mutex_lock(&daemon->mux);
	if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
		rc = 0;
		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;
		goto out_unlock_daemon;
	}
	/* This daemon will not go away so long as this flag is set */
	daemon->flags |= ECRYPTFS_DAEMON_IN_READ;
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;
	}
	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
 * @seq: Sequence number for miscdev response packet
 *
 * Returns zero on success; non-zero otherwise
 */
static int ecryptfs_miscdev_response(struct ecryptfs_daemon *daemon, char *data,
				     size_t data_size, 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(daemon, msg, 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
 * @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;
	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(file->private_data,
				&data[PKT_LEN_OFFSET + packet_size_length],
				packet_size, 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 <[email protected]>
	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
2ecaf55d	36	* @file: dev file
8bf2debd MH	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	{
2ecaf55d	44	struct ecryptfs_daemon *daemon = file->private_data;
8bf2debd	45	unsigned int mask = 0;
8bf2debd	46
8bf2debd	47	mutex_lock(&daemon->mux);
8bf2debd MH	48	if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
	49	printk(KERN_WARNING "%s: Attempt to poll on zombified "
	50	"daemon\n", __func__);
	51	goto out_unlock_daemon;
	52	}
	53	if (daemon->flags & ECRYPTFS_DAEMON_IN_READ)
	54	goto out_unlock_daemon;
	55	if (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)
	56	goto out_unlock_daemon;
	57	daemon->flags \|= ECRYPTFS_DAEMON_IN_POLL;
	58	mutex_unlock(&daemon->mux);
	59	poll_wait(file, &daemon->wait, pt);
	60	mutex_lock(&daemon->mux);
	61	if (!list_empty(&daemon->msg_ctx_out_queue))
	62	mask \|= POLLIN \| POLLRDNORM;
	63	out_unlock_daemon:
	64	daemon->flags &= ~ECRYPTFS_DAEMON_IN_POLL;
	65	mutex_unlock(&daemon->mux);
	66	return mask;
	67	}
	68
	69	/**
	70	* ecryptfs_miscdev_open
	71	* @inode: inode of miscdev handle (ignored)
2ecaf55d	72	* @file: file for miscdev handle
8bf2debd MH	73	*
	74	* Returns zero on success; non-zero otherwise
	75	*/
	76	static int
	77	ecryptfs_miscdev_open(struct inode inode, struct file file)
	78	{
	79	struct ecryptfs_daemon *daemon = NULL;
	80	int rc;
	81
	82	mutex_lock(&ecryptfs_daemon_hash_mux);
	83	rc = try_module_get(THIS_MODULE);
	84	if (rc == 0) {
	85	rc = -EIO;
	86	printk(KERN_ERR "%s: Error attempting to increment module use "
	87	"count; rc = [%d]\n", __func__, rc);
	88	goto out_unlock_daemon_list;
	89	}
2ecaf55d TH	90	rc = ecryptfs_find_daemon_by_euid(&daemon);
2ecaf55d TH	91	if (!rc) {
8bf2debd	92	rc = -EINVAL;
2ecaf55d TH	93	goto out_unlock_daemon_list;
	94	}
	95	rc = ecryptfs_spawn_daemon(&daemon, file);
	96	if (rc) {
	97	printk(KERN_ERR "%s: Error attempting to spawn daemon; "
	98	"rc = [%d]\n", __func__, rc);
	99	goto out_module_put_unlock_daemon_list;
8bf2debd	100	}
2ecaf55d	101	mutex_lock(&daemon->mux);
8bf2debd MH	102	if (daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN) {
8bf2debd MH	103	rc = -EBUSY;
8bf2debd MH	104	goto out_unlock_daemon;
	105	}
	106	daemon->flags \|= ECRYPTFS_DAEMON_MISCDEV_OPEN;
8dc67805	107	file->private_data = daemon;
8bf2debd MH	108	atomic_inc(&ecryptfs_num_miscdev_opens);
	109	out_unlock_daemon:
	110	mutex_unlock(&daemon->mux);
	111	out_module_put_unlock_daemon_list:
	112	if (rc)
	113	module_put(THIS_MODULE);
	114	out_unlock_daemon_list:
	115	mutex_unlock(&ecryptfs_daemon_hash_mux);
	116	return rc;
	117	}
	118
	119	/**
	120	* ecryptfs_miscdev_release
	121	* @inode: inode of fs/ecryptfs/euid handle (ignored)
2ecaf55d	122	* @file: file for fs/ecryptfs/euid handle
8bf2debd MH	123	*
	124	* This keeps the daemon registered until the daemon sends another
	125	* ioctl to fs/ecryptfs/ctl or until the kernel module unregisters.
	126	*
	127	* Returns zero on success; non-zero otherwise
	128	*/
	129	static int
	130	ecryptfs_miscdev_release(struct inode inode, struct file file)
	131	{
2ecaf55d	132	struct ecryptfs_daemon *daemon = file->private_data;
8bf2debd MH	133	int rc;
8bf2debd MH	134
8bf2debd	135	mutex_lock(&daemon->mux);
8bf2debd MH	136	BUG_ON(!(daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN));
	137	daemon->flags &= ~ECRYPTFS_DAEMON_MISCDEV_OPEN;
	138	atomic_dec(&ecryptfs_num_miscdev_opens);
	139	mutex_unlock(&daemon->mux);
2ecaf55d TH	140
2ecaf55d TH	141	mutex_lock(&ecryptfs_daemon_hash_mux);
8bf2debd	142	rc = ecryptfs_exorcise_daemon(daemon);
2ecaf55d	143	mutex_unlock(&ecryptfs_daemon_hash_mux);
8bf2debd MH	144	if (rc) {
	145	printk(KERN_CRIT "%s: Fatal error whilst attempting to "
	146	"shut down daemon; rc = [%d]. Please report this "
	147	"bug.\n", __func__, rc);
	148	BUG();
	149	}
	150	module_put(THIS_MODULE);
8bf2debd MH	151	return rc;
	152	}
	153
	154	/**
	155	* ecryptfs_send_miscdev
	156	* @data: Data to send to daemon; may be NULL
	157	* @data_size: Amount of data to send to daemon
	158	* @msg_ctx: Message context, which is used to handle the reply. If
	159	* this is NULL, then we do not expect a reply.
	160	* @msg_type: Type of message
	161	* @msg_flags: Flags for message
	162	* @daemon: eCryptfs daemon object
	163	*
	164	* Add msg_ctx to queue and then, if it exists, notify the blocked
	165	* miscdevess about the data being available. Must be called with
	166	* ecryptfs_daemon_hash_mux held.
	167	*
	168	* Returns zero on success; non-zero otherwise
	169	*/
	170	int ecryptfs_send_miscdev(char *data, size_t data_size,
	171	struct ecryptfs_msg_ctx *msg_ctx, u8 msg_type,
	172	u16 msg_flags, struct ecryptfs_daemon *daemon)
	173	{
60d65f1f	174	struct ecryptfs_message *msg;
8bf2debd	175
60d65f1f TH	176	msg = kmalloc((sizeof(*msg) + data_size), GFP_KERNEL);
60d65f1f TH	177	if (!msg) {
57ea34d1 TH	178	printk(KERN_ERR "%s: Out of memory whilst attempting "
57ea34d1 TH	179	"to kmalloc(%zd, GFP_KERNEL)\n", __func__,
60d65f1f TH	180	(sizeof(*msg) + data_size));
60d65f1f TH	181	return -ENOMEM;
57ea34d1	182	}
60d65f1f TH	183
	184	mutex_lock(&msg_ctx->mux);
	185	msg_ctx->msg = msg;
8bf2debd MH	186	msg_ctx->msg->index = msg_ctx->index;
	187	msg_ctx->msg->data_len = data_size;
	188	msg_ctx->type = msg_type;
57ea34d1 TH	189	memcpy(msg_ctx->msg->data, data, data_size);
57ea34d1 TH	190	msg_ctx->msg_size = (sizeof(*msg_ctx->msg) + data_size);
8bf2debd	191	list_add_tail(&msg_ctx->daemon_out_list, &daemon->msg_ctx_out_queue);
60d65f1f TH	192	mutex_unlock(&msg_ctx->mux);
	193
	194	mutex_lock(&daemon->mux);
8bf2debd MH	195	daemon->num_queued_msg_ctx++;
	196	wake_up_interruptible(&daemon->wait);
	197	mutex_unlock(&daemon->mux);
60d65f1f TH	198
60d65f1f TH	199	return 0;
8bf2debd MH	200	}
8bf2debd MH	201
48399c0b TH	202	/*
	203	* miscdevfs packet format:
	204	* Octet 0: Type
	205	* Octets 1-4: network byte order msg_ctx->counter
	206	* Octets 5-N0: Size of struct ecryptfs_message to follow
	207	* Octets N0-N1: struct ecryptfs_message (including data)
	208	*
	209	* Octets 5-N1 not written if the packet type does not include a message
	210	*/
	211	#define PKT_TYPE_SIZE 1
	212	#define PKT_CTR_SIZE 4
	213	#define MIN_NON_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE)
	214	#define MIN_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE \
	215	+ ECRYPTFS_MIN_PKT_LEN_SIZE)
	216	/* 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES comes from tag 65 packet format */
	217	#define MAX_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE \
	218	+ ECRYPTFS_MAX_PKT_LEN_SIZE \
	219	+ sizeof(struct ecryptfs_message) \
	220	+ 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES)
	221	#define PKT_TYPE_OFFSET 0
	222	#define PKT_CTR_OFFSET PKT_TYPE_SIZE
	223	#define PKT_LEN_OFFSET (PKT_TYPE_SIZE + PKT_CTR_SIZE)
	224
8bf2debd MH	225	/**
8bf2debd MH	226	* ecryptfs_miscdev_read - format and send message from queue
2ecaf55d	227	* @file: miscdevfs handle
8bf2debd MH	228	* @buf: User buffer into which to copy the next message on the daemon queue
	229	* @count: Amount of space available in @buf
	230	* @ppos: Offset in file (ignored)
	231	*
	232	* Pulls the most recent message from the daemon queue, formats it for
	233	* being sent via a miscdevfs handle, and copies it into @buf
	234	*
	235	* Returns the number of bytes copied into the user buffer
	236	*/
f66e883e	237	static ssize_t
8bf2debd MH	238	ecryptfs_miscdev_read(struct file file, char __user buf, size_t count,
	239	loff_t *ppos)
	240	{
2ecaf55d	241	struct ecryptfs_daemon *daemon = file->private_data;
8bf2debd MH	242	struct ecryptfs_msg_ctx *msg_ctx;
8bf2debd MH	243	size_t packet_length_size;
48399c0b	244	char packet_length[ECRYPTFS_MAX_PKT_LEN_SIZE];
8bf2debd MH	245	size_t i;
	246	size_t total_length;
	247	int rc;
	248
8bf2debd MH	249	mutex_lock(&daemon->mux);
	250	if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
	251	rc = 0;
	252	printk(KERN_WARNING "%s: Attempt to read from zombified "
	253	"daemon\n", __func__);
	254	goto out_unlock_daemon;
	255	}
	256	if (daemon->flags & ECRYPTFS_DAEMON_IN_READ) {
	257	rc = 0;
	258	goto out_unlock_daemon;
	259	}
	260	/* This daemon will not go away so long as this flag is set */
	261	daemon->flags \|= ECRYPTFS_DAEMON_IN_READ;
8bf2debd MH	262	check_list:
	263	if (list_empty(&daemon->msg_ctx_out_queue)) {
	264	mutex_unlock(&daemon->mux);
	265	rc = wait_event_interruptible(
	266	daemon->wait, !list_empty(&daemon->msg_ctx_out_queue));
	267	mutex_lock(&daemon->mux);
	268	if (rc < 0) {
	269	rc = 0;
	270	goto out_unlock_daemon;
	271	}
	272	}
	273	if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
	274	rc = 0;
	275	goto out_unlock_daemon;
	276	}
	277	if (list_empty(&daemon->msg_ctx_out_queue)) {
	278	/* Something else jumped in since the
	279	* wait_event_interruptable() and removed the
	280	* message from the queue; try again */
	281	goto check_list;
	282	}
8bf2debd MH	283	msg_ctx = list_first_entry(&daemon->msg_ctx_out_queue,
	284	struct ecryptfs_msg_ctx, daemon_out_list);
	285	BUG_ON(!msg_ctx);
	286	mutex_lock(&msg_ctx->mux);
	287	if (msg_ctx->msg) {
	288	rc = ecryptfs_write_packet_length(packet_length,
	289	msg_ctx->msg_size,
	290	&packet_length_size);
	291	if (rc) {
	292	rc = 0;
	293	printk(KERN_WARNING "%s: Error writing packet length; "
	294	"rc = [%d]\n", __func__, rc);
	295	goto out_unlock_msg_ctx;
	296	}
	297	} else {
	298	packet_length_size = 0;
	299	msg_ctx->msg_size = 0;
	300	}
48399c0b TH	301	total_length = (PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_length_size
48399c0b TH	302	+ msg_ctx->msg_size);
8bf2debd MH	303	if (count < total_length) {
	304	rc = 0;
	305	printk(KERN_WARNING "%s: Only given user buffer of "
df261c52	306	"size [%zd], but we need [%zd] to read the "
8bf2debd MH	307	"pending message\n", __func__, count, total_length);
	308	goto out_unlock_msg_ctx;
	309	}
79bc12a0 AV	310	rc = -EFAULT;
	311	if (put_user(msg_ctx->type, buf))
	312	goto out_unlock_msg_ctx;
48399c0b TH	313	if (put_user(cpu_to_be32(msg_ctx->counter),
48399c0b TH	314	(__be32 __user *)(&buf[PKT_CTR_OFFSET])))
79bc12a0	315	goto out_unlock_msg_ctx;
48399c0b	316	i = PKT_TYPE_SIZE + PKT_CTR_SIZE;
8bf2debd	317	if (msg_ctx->msg) {
79bc12a0 AV	318	if (copy_to_user(&buf[i], packet_length, packet_length_size))
79bc12a0 AV	319	goto out_unlock_msg_ctx;
8bf2debd	320	i += packet_length_size;
79bc12a0	321	if (copy_to_user(&buf[i], msg_ctx->msg, msg_ctx->msg_size))
8bf2debd	322	goto out_unlock_msg_ctx;
8bf2debd MH	323	i += msg_ctx->msg_size;
	324	}
	325	rc = i;
	326	list_del(&msg_ctx->daemon_out_list);
	327	kfree(msg_ctx->msg);
	328	msg_ctx->msg = NULL;
	329	/* We do not expect a reply from the userspace daemon for any
	330	* message type other than ECRYPTFS_MSG_REQUEST */
	331	if (msg_ctx->type != ECRYPTFS_MSG_REQUEST)
	332	ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
	333	out_unlock_msg_ctx:
	334	mutex_unlock(&msg_ctx->mux);
	335	out_unlock_daemon:
	336	daemon->flags &= ~ECRYPTFS_DAEMON_IN_READ;
	337	mutex_unlock(&daemon->mux);
	338	return rc;
	339	}
	340
8bf2debd MH	341	/**
	342	* ecryptfs_miscdev_response - miscdevess response to message previously sent to daemon
	343	* @data: Bytes comprising struct ecryptfs_message
	344	* @data_size: sizeof(struct ecryptfs_message) + data len
8bf2debd MH	345	* @seq: Sequence number for miscdev response packet
	346	*
	347	* Returns zero on success; non-zero otherwise
	348	*/
2ecaf55d TH	349	static int ecryptfs_miscdev_response(struct ecryptfs_daemon daemon, char data,
2ecaf55d TH	350	size_t data_size, u32 seq)
8bf2debd MH	351	{
	352	struct ecryptfs_message msg = (struct ecryptfs_message )data;
	353	int rc;
	354
	355	if ((sizeof(*msg) + msg->data_len) != data_size) {
	356	printk(KERN_WARNING "%s: (sizeof(*msg) + msg->data_len) = "
df261c52	357	"[%zd]; data_size = [%zd]. Invalid packet.\n", __func__,
8bf2debd MH	358	(sizeof(*msg) + msg->data_len), data_size);
	359	rc = -EINVAL;
	360	goto out;
	361	}
2ecaf55d	362	rc = ecryptfs_process_response(daemon, msg, seq);
8bf2debd MH	363	if (rc)
	364	printk(KERN_ERR
	365	"Error processing response message; rc = [%d]\n", rc);
	366	out:
	367	return rc;
	368	}
	369
	370	/**
	371	* ecryptfs_miscdev_write - handle write to daemon miscdev handle
2ecaf55d	372	* @file: File for misc dev handle
8bf2debd MH	373	* @buf: Buffer containing user data
	374	* @count: Amount of data in @buf
	375	* @ppos: Pointer to offset in file (ignored)
	376	*
8bf2debd MH	377	* Returns the number of bytes read from @buf
	378	*/
	379	static ssize_t
	380	ecryptfs_miscdev_write(struct file file, const char __user buf,
	381	size_t count, loff_t *ppos)
	382	{
79bc12a0 AV	383	__be32 counter_nbo;
79bc12a0 AV	384	u32 seq;
48399c0b	385	size_t packet_size, packet_size_length;
8bf2debd	386	char *data;
48399c0b	387	unsigned char packet_size_peek[ECRYPTFS_MAX_PKT_LEN_SIZE];
7f133504	388	ssize_t rc;
8bf2debd	389
db10e556	390	if (count == 0) {
7f133504	391	return 0;
48399c0b	392	} else if (count == MIN_NON_MSG_PKT_SIZE) {
db10e556 TH	393	/* Likely a harmless MSG_HELO or MSG_QUIT - no packet length */
db10e556 TH	394	goto memdup;
48399c0b	395	} else if (count < MIN_MSG_PKT_SIZE \|\| count > MAX_MSG_PKT_SIZE) {
db10e556	396	printk(KERN_WARNING "%s: Acceptable packet size range is "
164974a8	397	"[%d-%zu], but amount of data written is [%zu].",
48399c0b	398	__func__, MIN_MSG_PKT_SIZE, MAX_MSG_PKT_SIZE, count);
db10e556 TH	399	return -EINVAL;
	400	}
	401
48399c0b	402	if (copy_from_user(packet_size_peek, &buf[PKT_LEN_OFFSET],
db10e556 TH	403	sizeof(packet_size_peek))) {
	404	printk(KERN_WARNING "%s: Error while inspecting packet size\n",
	405	__func__);
	406	return -EFAULT;
	407	}
	408
	409	rc = ecryptfs_parse_packet_length(packet_size_peek, &packet_size,
	410	&packet_size_length);
	411	if (rc) {
	412	printk(KERN_WARNING "%s: Error parsing packet length; "
7f133504	413	"rc = [%zd]\n", __func__, rc);
db10e556 TH	414	return rc;
	415	}
	416
48399c0b TH	417	if ((PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_size_length + packet_size)
48399c0b TH	418	!= count) {
db10e556 TH	419	printk(KERN_WARNING "%s: Invalid packet size [%zu]\n", __func__,
	420	packet_size);
	421	return -EINVAL;
	422	}
fd56d242	423
db10e556	424	memdup:
fd56d242 LZ	425	data = memdup_user(buf, count);
	426	if (IS_ERR(data)) {
	427	printk(KERN_ERR "%s: memdup_user returned error [%ld]\n",
	428	__func__, PTR_ERR(data));
7f133504	429	return PTR_ERR(data);
8bf2debd	430	}
48399c0b	431	switch (data[PKT_TYPE_OFFSET]) {
8bf2debd	432	case ECRYPTFS_MSG_RESPONSE:
48399c0b TH	433	if (count < (MIN_MSG_PKT_SIZE
48399c0b TH	434	+ sizeof(struct ecryptfs_message))) {
8bf2debd	435	printk(KERN_WARNING "%s: Minimum acceptable packet "
df261c52 MH	436	"size is [%zd], but amount of data written is "
df261c52 MH	437	"only [%zd]. Discarding response packet.\n",
8bf2debd	438	__func__,
48399c0b TH	439	(MIN_MSG_PKT_SIZE
48399c0b TH	440	+ sizeof(struct ecryptfs_message)), count);
7f133504	441	rc = -EINVAL;
8bf2debd MH	442	goto out_free;
8bf2debd MH	443	}
48399c0b	444	memcpy(&counter_nbo, &data[PKT_CTR_OFFSET], PKT_CTR_SIZE);
8bf2debd	445	seq = be32_to_cpu(counter_nbo);
2ecaf55d	446	rc = ecryptfs_miscdev_response(file->private_data,
48399c0b	447	&data[PKT_LEN_OFFSET + packet_size_length],
2ecaf55d	448	packet_size, seq);
7f133504	449	if (rc) {
8bf2debd	450	printk(KERN_WARNING "%s: Failed to deliver miscdev "
7f133504	451	"response to requesting operation; rc = [%zd]\n",
8bf2debd	452	__func__, rc);
7f133504 TH	453	goto out_free;
7f133504 TH	454	}
8bf2debd MH	455	break;
8bf2debd MH	456	case ECRYPTFS_MSG_HELO:
8bf2debd	457	case ECRYPTFS_MSG_QUIT:
8bf2debd MH	458	break;
	459	default:
	460	ecryptfs_printk(KERN_WARNING, "Dropping miscdev "
	461	"message of unrecognized type [%d]\n",
	462	data[0]);
7f133504 TH	463	rc = -EINVAL;
7f133504 TH	464	goto out_free;
8bf2debd	465	}
7f133504	466	rc = count;
8bf2debd MH	467	out_free:
8bf2debd MH	468	kfree(data);
7f133504	469	return rc;
8bf2debd MH	470	}
	471
	472
	473	static const struct file_operations ecryptfs_miscdev_fops = {
	474	.open = ecryptfs_miscdev_open,
	475	.poll = ecryptfs_miscdev_poll,
	476	.read = ecryptfs_miscdev_read,
	477	.write = ecryptfs_miscdev_write,
	478	.release = ecryptfs_miscdev_release,
6038f373	479	.llseek = noop_llseek,
8bf2debd MH	480	};
	481
	482	static struct miscdevice ecryptfs_miscdev = {
	483	.minor = MISC_DYNAMIC_MINOR,
	484	.name = "ecryptfs",
	485	.fops = &ecryptfs_miscdev_fops
	486	};
	487
	488	/**
	489	* ecryptfs_init_ecryptfs_miscdev
	490	*
	491	* Messages sent to the userspace daemon from the kernel are placed on
	492	* a queue associated with the daemon. The next read against the
	493	* miscdev handle by that daemon will return the oldest message placed
	494	* on the message queue for the daemon.
	495	*
	496	* Returns zero on success; non-zero otherwise
	497	*/
7371a382	498	int __init ecryptfs_init_ecryptfs_miscdev(void)
8bf2debd MH	499	{
	500	int rc;
	501
	502	atomic_set(&ecryptfs_num_miscdev_opens, 0);
8bf2debd MH	503	rc = misc_register(&ecryptfs_miscdev);
	504	if (rc)
	505	printk(KERN_ERR "%s: Failed to register miscellaneous device "
	506	"for communications with userspace daemons; rc = [%d]\n",
	507	__func__, rc);
8bf2debd MH	508	return rc;
	509	}
	510
	511	/**
	512	* ecryptfs_destroy_ecryptfs_miscdev
	513	*
	514	* All of the daemons must be exorcised prior to calling this
	515	* function.
	516	*/
	517	void ecryptfs_destroy_ecryptfs_miscdev(void)
	518	{
	519	BUG_ON(atomic_read(&ecryptfs_num_miscdev_opens) != 0);
	520	misc_deregister(&ecryptfs_miscdev);
	521	}