2 * eCryptfs: Linux filesystem encryption layer
4 * Copyright (C) 2008 International Business Machines Corp.
5 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
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.
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.
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
23 #include <linux/hash.h>
24 #include <linux/random.h>
25 #include <linux/miscdevice.h>
26 #include <linux/poll.h>
27 #include <linux/slab.h>
28 #include <linux/wait.h>
29 #include <linux/module.h>
30 #include "ecryptfs_kernel.h"
32 static atomic_t ecryptfs_num_miscdev_opens;
35 * ecryptfs_miscdev_poll
36 * @file: dev file (ignored)
37 * @pt: dev poll table (ignored)
39 * Returns the poll mask
42 ecryptfs_miscdev_poll(struct file *file, poll_table *pt)
44 struct ecryptfs_daemon *daemon;
45 unsigned int mask = 0;
46 uid_t euid = current_euid();
49 mutex_lock(&ecryptfs_daemon_hash_mux);
50 /* TODO: Just use file->private_data? */
51 rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
53 mutex_unlock(&ecryptfs_daemon_hash_mux);
56 mutex_lock(&daemon->mux);
57 mutex_unlock(&ecryptfs_daemon_hash_mux);
58 if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
59 printk(KERN_WARNING "%s: Attempt to poll on zombified "
60 "daemon\n", __func__);
61 goto out_unlock_daemon;
63 if (daemon->flags & ECRYPTFS_DAEMON_IN_READ)
64 goto out_unlock_daemon;
65 if (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)
66 goto out_unlock_daemon;
67 daemon->flags |= ECRYPTFS_DAEMON_IN_POLL;
68 mutex_unlock(&daemon->mux);
69 poll_wait(file, &daemon->wait, pt);
70 mutex_lock(&daemon->mux);
71 if (!list_empty(&daemon->msg_ctx_out_queue))
72 mask |= POLLIN | POLLRDNORM;
74 daemon->flags &= ~ECRYPTFS_DAEMON_IN_POLL;
75 mutex_unlock(&daemon->mux);
80 * ecryptfs_miscdev_open
81 * @inode: inode of miscdev handle (ignored)
82 * @file: file for miscdev handle (ignored)
84 * Returns zero on success; non-zero otherwise
87 ecryptfs_miscdev_open(struct inode *inode, struct file *file)
89 struct ecryptfs_daemon *daemon = NULL;
90 uid_t euid = current_euid();
93 mutex_lock(&ecryptfs_daemon_hash_mux);
94 rc = try_module_get(THIS_MODULE);
97 printk(KERN_ERR "%s: Error attempting to increment module use "
98 "count; rc = [%d]\n", __func__, rc);
99 goto out_unlock_daemon_list;
101 rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
103 rc = ecryptfs_spawn_daemon(&daemon, euid, current_user_ns(),
106 printk(KERN_ERR "%s: Error attempting to spawn daemon; "
107 "rc = [%d]\n", __func__, rc);
108 goto out_module_put_unlock_daemon_list;
111 mutex_lock(&daemon->mux);
112 if (daemon->pid != task_pid(current)) {
114 printk(KERN_ERR "%s: pid [0x%p] has registered with euid [%d], "
115 "but pid [0x%p] has attempted to open the handle "
116 "instead\n", __func__, daemon->pid, daemon->euid,
118 goto out_unlock_daemon;
120 if (daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN) {
122 printk(KERN_ERR "%s: Miscellaneous device handle may only be "
123 "opened once per daemon; pid [0x%p] already has this "
124 "handle open\n", __func__, daemon->pid);
125 goto out_unlock_daemon;
127 daemon->flags |= ECRYPTFS_DAEMON_MISCDEV_OPEN;
128 file->private_data = daemon;
129 atomic_inc(&ecryptfs_num_miscdev_opens);
131 mutex_unlock(&daemon->mux);
132 out_module_put_unlock_daemon_list:
134 module_put(THIS_MODULE);
135 out_unlock_daemon_list:
136 mutex_unlock(&ecryptfs_daemon_hash_mux);
141 * ecryptfs_miscdev_release
142 * @inode: inode of fs/ecryptfs/euid handle (ignored)
143 * @file: file for fs/ecryptfs/euid handle (ignored)
145 * This keeps the daemon registered until the daemon sends another
146 * ioctl to fs/ecryptfs/ctl or until the kernel module unregisters.
148 * Returns zero on success; non-zero otherwise
151 ecryptfs_miscdev_release(struct inode *inode, struct file *file)
153 struct ecryptfs_daemon *daemon = NULL;
154 uid_t euid = current_euid();
157 mutex_lock(&ecryptfs_daemon_hash_mux);
158 rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
160 daemon = file->private_data;
161 mutex_lock(&daemon->mux);
162 BUG_ON(!(daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN));
163 daemon->flags &= ~ECRYPTFS_DAEMON_MISCDEV_OPEN;
164 atomic_dec(&ecryptfs_num_miscdev_opens);
165 mutex_unlock(&daemon->mux);
166 rc = ecryptfs_exorcise_daemon(daemon);
168 printk(KERN_CRIT "%s: Fatal error whilst attempting to "
169 "shut down daemon; rc = [%d]. Please report this "
170 "bug.\n", __func__, rc);
173 module_put(THIS_MODULE);
174 mutex_unlock(&ecryptfs_daemon_hash_mux);
179 * ecryptfs_send_miscdev
180 * @data: Data to send to daemon; may be NULL
181 * @data_size: Amount of data to send to daemon
182 * @msg_ctx: Message context, which is used to handle the reply. If
183 * this is NULL, then we do not expect a reply.
184 * @msg_type: Type of message
185 * @msg_flags: Flags for message
186 * @daemon: eCryptfs daemon object
188 * Add msg_ctx to queue and then, if it exists, notify the blocked
189 * miscdevess about the data being available. Must be called with
190 * ecryptfs_daemon_hash_mux held.
192 * Returns zero on success; non-zero otherwise
194 int ecryptfs_send_miscdev(char *data, size_t data_size,
195 struct ecryptfs_msg_ctx *msg_ctx, u8 msg_type,
196 u16 msg_flags, struct ecryptfs_daemon *daemon)
198 struct ecryptfs_message *msg;
200 msg = kmalloc((sizeof(*msg) + data_size), GFP_KERNEL);
202 printk(KERN_ERR "%s: Out of memory whilst attempting "
203 "to kmalloc(%zd, GFP_KERNEL)\n", __func__,
204 (sizeof(*msg) + data_size));
208 mutex_lock(&msg_ctx->mux);
210 msg_ctx->msg->index = msg_ctx->index;
211 msg_ctx->msg->data_len = data_size;
212 msg_ctx->type = msg_type;
213 memcpy(msg_ctx->msg->data, data, data_size);
214 msg_ctx->msg_size = (sizeof(*msg_ctx->msg) + data_size);
215 list_add_tail(&msg_ctx->daemon_out_list, &daemon->msg_ctx_out_queue);
216 mutex_unlock(&msg_ctx->mux);
218 mutex_lock(&daemon->mux);
219 daemon->num_queued_msg_ctx++;
220 wake_up_interruptible(&daemon->wait);
221 mutex_unlock(&daemon->mux);
227 * ecryptfs_miscdev_read - format and send message from queue
228 * @file: fs/ecryptfs/euid miscdevfs handle (ignored)
229 * @buf: User buffer into which to copy the next message on the daemon queue
230 * @count: Amount of space available in @buf
231 * @ppos: Offset in file (ignored)
233 * Pulls the most recent message from the daemon queue, formats it for
234 * being sent via a miscdevfs handle, and copies it into @buf
236 * Returns the number of bytes copied into the user buffer
239 ecryptfs_miscdev_read(struct file *file, char __user *buf, size_t count,
242 struct ecryptfs_daemon *daemon;
243 struct ecryptfs_msg_ctx *msg_ctx;
244 size_t packet_length_size;
245 char packet_length[3];
248 uid_t euid = current_euid();
251 mutex_lock(&ecryptfs_daemon_hash_mux);
252 /* TODO: Just use file->private_data? */
253 rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
255 mutex_unlock(&ecryptfs_daemon_hash_mux);
258 mutex_lock(&daemon->mux);
259 if (task_pid(current) != daemon->pid) {
260 mutex_unlock(&daemon->mux);
261 mutex_unlock(&ecryptfs_daemon_hash_mux);
264 if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
266 mutex_unlock(&ecryptfs_daemon_hash_mux);
267 printk(KERN_WARNING "%s: Attempt to read from zombified "
268 "daemon\n", __func__);
269 goto out_unlock_daemon;
271 if (daemon->flags & ECRYPTFS_DAEMON_IN_READ) {
273 mutex_unlock(&ecryptfs_daemon_hash_mux);
274 goto out_unlock_daemon;
276 /* This daemon will not go away so long as this flag is set */
277 daemon->flags |= ECRYPTFS_DAEMON_IN_READ;
278 mutex_unlock(&ecryptfs_daemon_hash_mux);
280 if (list_empty(&daemon->msg_ctx_out_queue)) {
281 mutex_unlock(&daemon->mux);
282 rc = wait_event_interruptible(
283 daemon->wait, !list_empty(&daemon->msg_ctx_out_queue));
284 mutex_lock(&daemon->mux);
287 goto out_unlock_daemon;
290 if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
292 goto out_unlock_daemon;
294 if (list_empty(&daemon->msg_ctx_out_queue)) {
295 /* Something else jumped in since the
296 * wait_event_interruptable() and removed the
297 * message from the queue; try again */
300 msg_ctx = list_first_entry(&daemon->msg_ctx_out_queue,
301 struct ecryptfs_msg_ctx, daemon_out_list);
303 mutex_lock(&msg_ctx->mux);
305 rc = ecryptfs_write_packet_length(packet_length,
307 &packet_length_size);
310 printk(KERN_WARNING "%s: Error writing packet length; "
311 "rc = [%d]\n", __func__, rc);
312 goto out_unlock_msg_ctx;
315 packet_length_size = 0;
316 msg_ctx->msg_size = 0;
318 /* miscdevfs packet format:
320 * Octets 1-4: network byte order msg_ctx->counter
321 * Octets 5-N0: Size of struct ecryptfs_message to follow
322 * Octets N0-N1: struct ecryptfs_message (including data)
324 * Octets 5-N1 not written if the packet type does not
325 * include a message */
326 total_length = (1 + 4 + packet_length_size + msg_ctx->msg_size);
327 if (count < total_length) {
329 printk(KERN_WARNING "%s: Only given user buffer of "
330 "size [%zd], but we need [%zd] to read the "
331 "pending message\n", __func__, count, total_length);
332 goto out_unlock_msg_ctx;
335 if (put_user(msg_ctx->type, buf))
336 goto out_unlock_msg_ctx;
337 if (put_user(cpu_to_be32(msg_ctx->counter), (__be32 __user *)(buf + 1)))
338 goto out_unlock_msg_ctx;
341 if (copy_to_user(&buf[i], packet_length, packet_length_size))
342 goto out_unlock_msg_ctx;
343 i += packet_length_size;
344 if (copy_to_user(&buf[i], msg_ctx->msg, msg_ctx->msg_size))
345 goto out_unlock_msg_ctx;
346 i += msg_ctx->msg_size;
349 list_del(&msg_ctx->daemon_out_list);
352 /* We do not expect a reply from the userspace daemon for any
353 * message type other than ECRYPTFS_MSG_REQUEST */
354 if (msg_ctx->type != ECRYPTFS_MSG_REQUEST)
355 ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
357 mutex_unlock(&msg_ctx->mux);
359 daemon->flags &= ~ECRYPTFS_DAEMON_IN_READ;
360 mutex_unlock(&daemon->mux);
365 * ecryptfs_miscdev_response - miscdevess response to message previously sent to daemon
366 * @data: Bytes comprising struct ecryptfs_message
367 * @data_size: sizeof(struct ecryptfs_message) + data len
368 * @euid: Effective user id of miscdevess sending the miscdev response
369 * @user_ns: The namespace in which @euid applies
370 * @pid: Miscdevess id of miscdevess sending the miscdev response
371 * @seq: Sequence number for miscdev response packet
373 * Returns zero on success; non-zero otherwise
375 static int ecryptfs_miscdev_response(char *data, size_t data_size,
376 uid_t euid, struct user_namespace *user_ns,
377 struct pid *pid, u32 seq)
379 struct ecryptfs_message *msg = (struct ecryptfs_message *)data;
382 if ((sizeof(*msg) + msg->data_len) != data_size) {
383 printk(KERN_WARNING "%s: (sizeof(*msg) + msg->data_len) = "
384 "[%zd]; data_size = [%zd]. Invalid packet.\n", __func__,
385 (sizeof(*msg) + msg->data_len), data_size);
389 rc = ecryptfs_process_response(msg, euid, user_ns, pid, seq);
392 "Error processing response message; rc = [%d]\n", rc);
398 * ecryptfs_miscdev_write - handle write to daemon miscdev handle
399 * @file: File for misc dev handle (ignored)
400 * @buf: Buffer containing user data
401 * @count: Amount of data in @buf
402 * @ppos: Pointer to offset in file (ignored)
404 * miscdevfs packet format:
406 * Octets 1-4: network byte order msg_ctx->counter (0's for non-response)
407 * Octets 5-N0: Size of struct ecryptfs_message to follow
408 * Octets N0-N1: struct ecryptfs_message (including data)
410 * Returns the number of bytes read from @buf
413 ecryptfs_miscdev_write(struct file *file, const char __user *buf,
414 size_t count, loff_t *ppos)
418 size_t packet_size, packet_size_length, i;
421 uid_t euid = current_euid();
422 unsigned char packet_size_peek[3];
427 } else if (count == (1 + 4)) {
428 /* Likely a harmless MSG_HELO or MSG_QUIT - no packet length */
430 } else if (count < (1 + 4 + 1)
431 || count > (1 + 4 + 2 + sizeof(struct ecryptfs_message) + 4
432 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES)) {
433 printk(KERN_WARNING "%s: Acceptable packet size range is "
434 "[%d-%lu], but amount of data written is [%zu].",
435 __func__, (1 + 4 + 1),
436 (1 + 4 + 2 + sizeof(struct ecryptfs_message) + 4
437 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES), count);
441 if (copy_from_user(packet_size_peek, (buf + 1 + 4),
442 sizeof(packet_size_peek))) {
443 printk(KERN_WARNING "%s: Error while inspecting packet size\n",
448 rc = ecryptfs_parse_packet_length(packet_size_peek, &packet_size,
449 &packet_size_length);
451 printk(KERN_WARNING "%s: Error parsing packet length; "
452 "rc = [%d]\n", __func__, rc);
456 if ((1 + 4 + packet_size_length + packet_size) != count) {
457 printk(KERN_WARNING "%s: Invalid packet size [%zu]\n", __func__,
463 data = memdup_user(buf, count);
465 printk(KERN_ERR "%s: memdup_user returned error [%ld]\n",
466 __func__, PTR_ERR(data));
472 case ECRYPTFS_MSG_RESPONSE:
473 if (count < (1 + 4 + 1 + sizeof(struct ecryptfs_message))) {
474 printk(KERN_WARNING "%s: Minimum acceptable packet "
475 "size is [%zd], but amount of data written is "
476 "only [%zd]. Discarding response packet.\n",
478 (1 + 4 + 1 + sizeof(struct ecryptfs_message)),
482 memcpy(&counter_nbo, &data[i], 4);
483 seq = be32_to_cpu(counter_nbo);
484 i += 4 + packet_size_length;
485 rc = ecryptfs_miscdev_response(&data[i], packet_size,
486 euid, current_user_ns(),
487 task_pid(current), seq);
489 printk(KERN_WARNING "%s: Failed to deliver miscdev "
490 "response to requesting operation; rc = [%d]\n",
493 case ECRYPTFS_MSG_HELO:
494 case ECRYPTFS_MSG_QUIT:
497 ecryptfs_printk(KERN_WARNING, "Dropping miscdev "
498 "message of unrecognized type [%d]\n",
509 static const struct file_operations ecryptfs_miscdev_fops = {
510 .open = ecryptfs_miscdev_open,
511 .poll = ecryptfs_miscdev_poll,
512 .read = ecryptfs_miscdev_read,
513 .write = ecryptfs_miscdev_write,
514 .release = ecryptfs_miscdev_release,
515 .llseek = noop_llseek,
518 static struct miscdevice ecryptfs_miscdev = {
519 .minor = MISC_DYNAMIC_MINOR,
521 .fops = &ecryptfs_miscdev_fops
525 * ecryptfs_init_ecryptfs_miscdev
527 * Messages sent to the userspace daemon from the kernel are placed on
528 * a queue associated with the daemon. The next read against the
529 * miscdev handle by that daemon will return the oldest message placed
530 * on the message queue for the daemon.
532 * Returns zero on success; non-zero otherwise
534 int __init ecryptfs_init_ecryptfs_miscdev(void)
538 atomic_set(&ecryptfs_num_miscdev_opens, 0);
539 rc = misc_register(&ecryptfs_miscdev);
541 printk(KERN_ERR "%s: Failed to register miscellaneous device "
542 "for communications with userspace daemons; rc = [%d]\n",
548 * ecryptfs_destroy_ecryptfs_miscdev
550 * All of the daemons must be exorcised prior to calling this
553 void ecryptfs_destroy_ecryptfs_miscdev(void)
555 BUG_ON(atomic_read(&ecryptfs_num_miscdev_opens) != 0);
556 misc_deregister(&ecryptfs_miscdev);