/** * 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 intecryptfs_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 intecryptfs_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 intecryptfs_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;} /** * 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_tecryptfs_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[3];	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;	}	/* 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 */	total_length = (1 + 4 + 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 + 1)))		goto out_unlock_msg_ctx;	i = 5;	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) * * miscdevfs packet format: *  Octet 0: Type *  Octets 1-4: network byte order msg_ctx->counter (0's for non-response) *  Octets 5-N0: Size of struct ecryptfs_message to follow *  Octets N0-N1: struct ecryptfs_message (including data) * * Returns the number of bytes read from @buf */static ssize_tecryptfs_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, i;	ssize_t sz = 0;	char *data;	uid_t euid = current_euid();	int rc; 	if (count == 0)		goto out; 	data = memdup_user(buf, count);	if (IS_ERR(data)) {		printk(KERN_ERR "%s: memdup_user returned error [%ld]\n",		       __func__, PTR_ERR(data));		goto out;	}	sz = count;	i = 0;	switch (data[i++]) {	case ECRYPTFS_MSG_RESPONSE:		if (count < (1 + 4 + 1 + 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__,			       (1 + 4 + 1 + sizeof(struct ecryptfs_message)),			       count);			goto out_free;		}		memcpy(&counter_nbo, &data[i], 4);		seq = be32_to_cpu(counter_nbo);		i += 4;		rc = ecryptfs_parse_packet_length(&data[i], &packet_size,						  &packet_size_length);		if (rc) {			printk(KERN_WARNING "%s: Error parsing packet length; "			       "rc = [%d]\n", __func__, rc);			goto out_free;		}		i += packet_size_length;		if ((1 + 4 + packet_size_length + packet_size) != count) {			printk(KERN_WARNING "%s: (1 + packet_size_length([%zd])"			       " + packet_size([%zd]))([%zd]) != "			       "count([%zd]). Invalid packet format.\n",			       __func__, packet_size_length, packet_size,			       (1 + packet_size_length + packet_size), count);			goto out_free;		}		rc = ecryptfs_miscdev_response(&data[i], 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 = [%d]\n",			       __func__, rc);		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]);		break;	}out_free:	kfree(data);out:	return sz;}  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,}; 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. *

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