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 * miscdevfs packet format:
229 * Octets 1-4: network byte order msg_ctx->counter
230 * Octets 5-N0: Size of struct ecryptfs_message to follow
231 * Octets N0-N1: struct ecryptfs_message (including data)
233 * Octets 5-N1 not written if the packet type does not include a message
235 #define PKT_TYPE_SIZE 1
236 #define PKT_CTR_SIZE 4
237 #define MIN_NON_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE)
238 #define MIN_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE \
239 + ECRYPTFS_MIN_PKT_LEN_SIZE)
240 /* 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES comes from tag 65 packet format */
241 #define MAX_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE \
242 + ECRYPTFS_MAX_PKT_LEN_SIZE \
243 + sizeof(struct ecryptfs_message) \
244 + 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES)
245 #define PKT_TYPE_OFFSET 0
246 #define PKT_CTR_OFFSET PKT_TYPE_SIZE
247 #define PKT_LEN_OFFSET (PKT_TYPE_SIZE + PKT_CTR_SIZE)
250 * ecryptfs_miscdev_read - format and send message from queue
251 * @file: fs/ecryptfs/euid miscdevfs handle (ignored)
252 * @buf: User buffer into which to copy the next message on the daemon queue
253 * @count: Amount of space available in @buf
254 * @ppos: Offset in file (ignored)
256 * Pulls the most recent message from the daemon queue, formats it for
257 * being sent via a miscdevfs handle, and copies it into @buf
259 * Returns the number of bytes copied into the user buffer
262 ecryptfs_miscdev_read(struct file
*file
, char __user
*buf
, size_t count
,
265 struct ecryptfs_daemon
*daemon
;
266 struct ecryptfs_msg_ctx
*msg_ctx
;
267 size_t packet_length_size
;
268 char packet_length
[ECRYPTFS_MAX_PKT_LEN_SIZE
];
271 uid_t euid
= current_euid();
274 mutex_lock(&ecryptfs_daemon_hash_mux
);
275 /* TODO: Just use file->private_data? */
276 rc
= ecryptfs_find_daemon_by_euid(&daemon
, euid
, current_user_ns());
278 mutex_unlock(&ecryptfs_daemon_hash_mux
);
281 mutex_lock(&daemon
->mux
);
282 if (task_pid(current
) != daemon
->pid
) {
283 mutex_unlock(&daemon
->mux
);
284 mutex_unlock(&ecryptfs_daemon_hash_mux
);
287 if (daemon
->flags
& ECRYPTFS_DAEMON_ZOMBIE
) {
289 mutex_unlock(&ecryptfs_daemon_hash_mux
);
290 printk(KERN_WARNING
"%s: Attempt to read from zombified "
291 "daemon\n", __func__
);
292 goto out_unlock_daemon
;
294 if (daemon
->flags
& ECRYPTFS_DAEMON_IN_READ
) {
296 mutex_unlock(&ecryptfs_daemon_hash_mux
);
297 goto out_unlock_daemon
;
299 /* This daemon will not go away so long as this flag is set */
300 daemon
->flags
|= ECRYPTFS_DAEMON_IN_READ
;
301 mutex_unlock(&ecryptfs_daemon_hash_mux
);
303 if (list_empty(&daemon
->msg_ctx_out_queue
)) {
304 mutex_unlock(&daemon
->mux
);
305 rc
= wait_event_interruptible(
306 daemon
->wait
, !list_empty(&daemon
->msg_ctx_out_queue
));
307 mutex_lock(&daemon
->mux
);
310 goto out_unlock_daemon
;
313 if (daemon
->flags
& ECRYPTFS_DAEMON_ZOMBIE
) {
315 goto out_unlock_daemon
;
317 if (list_empty(&daemon
->msg_ctx_out_queue
)) {
318 /* Something else jumped in since the
319 * wait_event_interruptable() and removed the
320 * message from the queue; try again */
323 msg_ctx
= list_first_entry(&daemon
->msg_ctx_out_queue
,
324 struct ecryptfs_msg_ctx
, daemon_out_list
);
326 mutex_lock(&msg_ctx
->mux
);
328 rc
= ecryptfs_write_packet_length(packet_length
,
330 &packet_length_size
);
333 printk(KERN_WARNING
"%s: Error writing packet length; "
334 "rc = [%d]\n", __func__
, rc
);
335 goto out_unlock_msg_ctx
;
338 packet_length_size
= 0;
339 msg_ctx
->msg_size
= 0;
341 total_length
= (PKT_TYPE_SIZE
+ PKT_CTR_SIZE
+ packet_length_size
342 + msg_ctx
->msg_size
);
343 if (count
< total_length
) {
345 printk(KERN_WARNING
"%s: Only given user buffer of "
346 "size [%zd], but we need [%zd] to read the "
347 "pending message\n", __func__
, count
, total_length
);
348 goto out_unlock_msg_ctx
;
351 if (put_user(msg_ctx
->type
, buf
))
352 goto out_unlock_msg_ctx
;
353 if (put_user(cpu_to_be32(msg_ctx
->counter
),
354 (__be32 __user
*)(&buf
[PKT_CTR_OFFSET
])))
355 goto out_unlock_msg_ctx
;
356 i
= PKT_TYPE_SIZE
+ PKT_CTR_SIZE
;
358 if (copy_to_user(&buf
[i
], packet_length
, packet_length_size
))
359 goto out_unlock_msg_ctx
;
360 i
+= packet_length_size
;
361 if (copy_to_user(&buf
[i
], msg_ctx
->msg
, msg_ctx
->msg_size
))
362 goto out_unlock_msg_ctx
;
363 i
+= msg_ctx
->msg_size
;
366 list_del(&msg_ctx
->daemon_out_list
);
369 /* We do not expect a reply from the userspace daemon for any
370 * message type other than ECRYPTFS_MSG_REQUEST */
371 if (msg_ctx
->type
!= ECRYPTFS_MSG_REQUEST
)
372 ecryptfs_msg_ctx_alloc_to_free(msg_ctx
);
374 mutex_unlock(&msg_ctx
->mux
);
376 daemon
->flags
&= ~ECRYPTFS_DAEMON_IN_READ
;
377 mutex_unlock(&daemon
->mux
);
382 * ecryptfs_miscdev_response - miscdevess response to message previously sent to daemon
383 * @data: Bytes comprising struct ecryptfs_message
384 * @data_size: sizeof(struct ecryptfs_message) + data len
385 * @euid: Effective user id of miscdevess sending the miscdev response
386 * @user_ns: The namespace in which @euid applies
387 * @pid: Miscdevess id of miscdevess sending the miscdev response
388 * @seq: Sequence number for miscdev response packet
390 * Returns zero on success; non-zero otherwise
392 static int ecryptfs_miscdev_response(char *data
, size_t data_size
,
393 uid_t euid
, struct user_namespace
*user_ns
,
394 struct pid
*pid
, u32 seq
)
396 struct ecryptfs_message
*msg
= (struct ecryptfs_message
*)data
;
399 if ((sizeof(*msg
) + msg
->data_len
) != data_size
) {
400 printk(KERN_WARNING
"%s: (sizeof(*msg) + msg->data_len) = "
401 "[%zd]; data_size = [%zd]. Invalid packet.\n", __func__
,
402 (sizeof(*msg
) + msg
->data_len
), data_size
);
406 rc
= ecryptfs_process_response(msg
, euid
, user_ns
, pid
, seq
);
409 "Error processing response message; rc = [%d]\n", rc
);
415 * ecryptfs_miscdev_write - handle write to daemon miscdev handle
416 * @file: File for misc dev handle (ignored)
417 * @buf: Buffer containing user data
418 * @count: Amount of data in @buf
419 * @ppos: Pointer to offset in file (ignored)
421 * Returns the number of bytes read from @buf
424 ecryptfs_miscdev_write(struct file
*file
, const char __user
*buf
,
425 size_t count
, loff_t
*ppos
)
429 size_t packet_size
, packet_size_length
;
431 uid_t euid
= current_euid();
432 unsigned char packet_size_peek
[ECRYPTFS_MAX_PKT_LEN_SIZE
];
437 } else if (count
== MIN_NON_MSG_PKT_SIZE
) {
438 /* Likely a harmless MSG_HELO or MSG_QUIT - no packet length */
440 } else if (count
< MIN_MSG_PKT_SIZE
|| count
> MAX_MSG_PKT_SIZE
) {
441 printk(KERN_WARNING
"%s: Acceptable packet size range is "
442 "[%d-%zu], but amount of data written is [%zu].",
443 __func__
, MIN_MSG_PKT_SIZE
, MAX_MSG_PKT_SIZE
, count
);
447 if (copy_from_user(packet_size_peek
, &buf
[PKT_LEN_OFFSET
],
448 sizeof(packet_size_peek
))) {
449 printk(KERN_WARNING
"%s: Error while inspecting packet size\n",
454 rc
= ecryptfs_parse_packet_length(packet_size_peek
, &packet_size
,
455 &packet_size_length
);
457 printk(KERN_WARNING
"%s: Error parsing packet length; "
458 "rc = [%zd]\n", __func__
, rc
);
462 if ((PKT_TYPE_SIZE
+ PKT_CTR_SIZE
+ packet_size_length
+ packet_size
)
464 printk(KERN_WARNING
"%s: Invalid packet size [%zu]\n", __func__
,
470 data
= memdup_user(buf
, count
);
472 printk(KERN_ERR
"%s: memdup_user returned error [%ld]\n",
473 __func__
, PTR_ERR(data
));
474 return PTR_ERR(data
);
476 switch (data
[PKT_TYPE_OFFSET
]) {
477 case ECRYPTFS_MSG_RESPONSE
:
478 if (count
< (MIN_MSG_PKT_SIZE
479 + sizeof(struct ecryptfs_message
))) {
480 printk(KERN_WARNING
"%s: Minimum acceptable packet "
481 "size is [%zd], but amount of data written is "
482 "only [%zd]. Discarding response packet.\n",
485 + sizeof(struct ecryptfs_message
)), count
);
489 memcpy(&counter_nbo
, &data
[PKT_CTR_OFFSET
], PKT_CTR_SIZE
);
490 seq
= be32_to_cpu(counter_nbo
);
491 rc
= ecryptfs_miscdev_response(
492 &data
[PKT_LEN_OFFSET
+ packet_size_length
],
493 packet_size
, euid
, current_user_ns(),
494 task_pid(current
), seq
);
496 printk(KERN_WARNING
"%s: Failed to deliver miscdev "
497 "response to requesting operation; rc = [%zd]\n",
502 case ECRYPTFS_MSG_HELO
:
503 case ECRYPTFS_MSG_QUIT
:
506 ecryptfs_printk(KERN_WARNING
, "Dropping miscdev "
507 "message of unrecognized type [%d]\n",
519 static const struct file_operations ecryptfs_miscdev_fops
= {
520 .open
= ecryptfs_miscdev_open
,
521 .poll
= ecryptfs_miscdev_poll
,
522 .read
= ecryptfs_miscdev_read
,
523 .write
= ecryptfs_miscdev_write
,
524 .release
= ecryptfs_miscdev_release
,
525 .llseek
= noop_llseek
,
528 static struct miscdevice ecryptfs_miscdev
= {
529 .minor
= MISC_DYNAMIC_MINOR
,
531 .fops
= &ecryptfs_miscdev_fops
535 * ecryptfs_init_ecryptfs_miscdev
537 * Messages sent to the userspace daemon from the kernel are placed on
538 * a queue associated with the daemon. The next read against the
539 * miscdev handle by that daemon will return the oldest message placed
540 * on the message queue for the daemon.
542 * Returns zero on success; non-zero otherwise
544 int __init
ecryptfs_init_ecryptfs_miscdev(void)
548 atomic_set(&ecryptfs_num_miscdev_opens
, 0);
549 rc
= misc_register(&ecryptfs_miscdev
);
551 printk(KERN_ERR
"%s: Failed to register miscellaneous device "
552 "for communications with userspace daemons; rc = [%d]\n",
558 * ecryptfs_destroy_ecryptfs_miscdev
560 * All of the daemons must be exorcised prior to calling this
563 void ecryptfs_destroy_ecryptfs_miscdev(void)
565 BUG_ON(atomic_read(&ecryptfs_num_miscdev_opens
) != 0);
566 misc_deregister(&ecryptfs_miscdev
);