1 files changed, 580 insertions, 0 deletions

diff --git a/fs/ecryptfs/miscdev.c b/fs/ecryptfs/miscdev.c
new file mode 100644
index 00000000000..72dfec48ea2
--- /dev/null
+++ b/fs/ecryptfs/miscdev.c
@@ -0,0 +1,580 @@
+/**
+ * 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/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;
+	int rc;
+
+	mutex_lock(&ecryptfs_daemon_hash_mux);
+	/* TODO: Just use file->private_data? */
+	rc = ecryptfs_find_daemon_by_euid(&daemon, current->euid);
+	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;
+	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, current->euid);
+	if (rc || !daemon) {
+		rc = ecryptfs_spawn_daemon(&daemon, current->euid,
+					   current->pid);
+		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 != current->pid) {
+		rc = -EINVAL;
+		printk(KERN_ERR "%s: pid [%d] has registered with euid [%d], "
+		       "but pid [%d] has attempted to open the handle "
+		       "instead\n", __func__, daemon->pid, daemon->euid,
+		       current->pid);
+		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 [%d] 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;
+	int rc;
+
+	mutex_lock(&ecryptfs_daemon_hash_mux);
+	rc = ecryptfs_find_daemon_by_euid(&daemon, current->euid);
+	BUG_ON(rc || !daemon);
+	mutex_lock(&daemon->mux);
+	BUG_ON(daemon->pid != current->pid);
+	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);
+	if (data) {
+		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(%d, GFP_KERNEL)\n", __func__,
+			       (sizeof(*msg_ctx->msg) + data_size));
+			goto out_unlock;
+		}
+	} else
+		msg_ctx->msg = NULL;
+	msg_ctx->msg->index = msg_ctx->index;
+	msg_ctx->msg->data_len = data_size;
+	msg_ctx->type = msg_type;
+	if (data) {
+		memcpy(msg_ctx->msg->data, data, data_size);
+		msg_ctx->msg_size = (sizeof(*msg_ctx->msg) + data_size);
+	} else
+		msg_ctx->msg_size = 0;
+	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 int
+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;
+	u32 counter_nbo;
+	char packet_length[3];
+	size_t i;
+	size_t total_length;
+	int rc;
+
+	mutex_lock(&ecryptfs_daemon_hash_mux);
+	/* TODO: Just use file->private_data? */
+	rc = ecryptfs_find_daemon_by_euid(&daemon, current->euid);
+	BUG_ON(rc || !daemon);
+	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;
+	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(current->euid != daemon->euid);
+	BUG_ON(current->pid != 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;
+	}
+	i = 0;
+	buf[i++] = msg_ctx->type;
+	counter_nbo = cpu_to_be32(msg_ctx->counter);
+	memcpy(&buf[i], (char *)&counter_nbo, 4);
+	i += 4;
+	if (msg_ctx->msg) {
+		memcpy(&buf[i], packet_length, packet_length_size);
+		i += packet_length_size;
+		rc = copy_to_user(&buf[i], msg_ctx->msg, msg_ctx->msg_size);
+		if (rc) {
+			printk(KERN_ERR "%s: copy_to_user returned error "
+			       "[%d]\n", __func__, rc);
+			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_helo
+ * @euid: effective user id of miscdevess sending helo packet
+ * @pid: miscdevess id of miscdevess sending helo packet
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_miscdev_helo(uid_t uid, pid_t pid)
+{
+	int rc;
+
+	rc = ecryptfs_process_helo(ECRYPTFS_TRANSPORT_MISCDEV, uid, pid);
+	if (rc)
+		printk(KERN_WARNING "Error processing HELO; rc = [%d]\n", rc);
+	return rc;
+}
+
+/**
+ * ecryptfs_miscdev_quit
+ * @euid: effective user id of miscdevess sending quit packet
+ * @pid: miscdevess id of miscdevess sending quit packet
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_miscdev_quit(uid_t euid, pid_t pid)
+{
+	int rc;
+
+	rc = ecryptfs_process_quit(euid, pid);
+	if (rc)
+		printk(KERN_WARNING
+		       "Error processing QUIT message; rc = [%d]\n", rc);
+	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
+ * @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, pid_t 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, 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_t
+ecryptfs_miscdev_write(struct file *file, const char __user *buf,
+		       size_t count, loff_t *ppos)
+{
+	u32 counter_nbo, seq;
+	size_t packet_size, packet_size_length, i;
+	ssize_t sz = 0;
+	char *data;
+	int rc;
+
+	if (count == 0)
+		goto out;
+	data = kmalloc(count, GFP_KERNEL);
+	if (!data) {
+		printk(KERN_ERR "%s: Out of memory whilst attempting to "
+		       "kmalloc([%Zd], GFP_KERNEL)\n", __func__, count);
+		goto out;
+	}
+	rc = copy_from_user(data, buf, count);
+	if (rc) {
+		printk(KERN_ERR "%s: copy_from_user returned error [%d]\n",
+		       __func__, rc);
+		goto out_free;
+	}
+	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((char *)&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,
+					       current->euid,
+					       current->pid, 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:
+		rc = ecryptfs_miscdev_helo(current->euid, current->pid);
+		if (rc) {
+			printk(KERN_ERR "%s: Error attempting to process "
+			       "helo from pid [%d]; rc = [%d]\n", __func__,
+			       current->pid, rc);
+			goto out_free;
+		}
+		break;
+	case ECRYPTFS_MSG_QUIT:
+		rc = ecryptfs_miscdev_quit(current->euid, current->pid);
+		if (rc) {
+			printk(KERN_ERR "%s: Error attempting to process "
+			       "quit from pid [%d]; rc = [%d]\n", __func__,
+			       current->pid, rc);
+			goto out_free;
+		}
+		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.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_init_ecryptfs_miscdev(void)
+{
+	int rc;
+
+	atomic_set(&ecryptfs_num_miscdev_opens, 0);
+	mutex_lock(&ecryptfs_daemon_hash_mux);
+	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);
+	mutex_unlock(&ecryptfs_daemon_hash_mux);
+	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);
+}