// SPDX-License-Identifier: GPL-2.0-only/* * eCryptfs: Linux filesystem encryption layer * * Copyright (C) 2008 International Business Machines Corp. *   Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com> */ #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 __poll_tecryptfs_miscdev_poll(struct file *file, poll_table *pt){	struct ecryptfs_daemon *daemon = file->private_data;	__poll_t 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 |= EPOLLIN | EPOLLRDNORM;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 intecryptfs_miscdev_open(struct inode *inode, struct file *file){	struct ecryptfs_daemon *daemon = NULL;	int rc; 	mutex_lock(&ecryptfs_daemon_hash_mux);	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_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_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 intecryptfs_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();	}	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)		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_tecryptfs_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 * @daemon: eCryptfs daemon object * @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_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;	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].\n",		       __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 = {	.owner   = THIS_MODULE,	.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);}