538 lines
16 KiB
C
538 lines
16 KiB
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/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,
|
|
current->nsproxy->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;
|
|
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,
|
|
current->nsproxy->user_ns);
|
|
if (rc || !daemon) {
|
|
rc = ecryptfs_spawn_daemon(&daemon, current->euid,
|
|
current->nsproxy->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;
|
|
int rc;
|
|
|
|
mutex_lock(&ecryptfs_daemon_hash_mux);
|
|
rc = ecryptfs_find_daemon_by_euid(&daemon, current->euid,
|
|
current->nsproxy->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);
|
|
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(%Zd, 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 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[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,
|
|
current->nsproxy->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(current->euid != daemon->euid);
|
|
BUG_ON(current->nsproxy->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_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, 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(&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->nsproxy->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.
|
|
*
|
|
* Returns zero on success; non-zero otherwise
|
|
*/
|
|
int 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);
|
|
}
|