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1/**
2 * eCryptfs: Linux filesystem encryption layer
3 *
4 * Copyright (C) 2008 International Business Machines Corp.
5 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
6 *
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.
10 *
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.
15 *
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
19 * 02111-1307, USA.
20 */
21
22#include <linux/fs.h>
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"
31
32static atomic_t ecryptfs_num_miscdev_opens;
33
34/**
35 * ecryptfs_miscdev_poll
36 * @file: dev file
37 * @pt: dev poll table (ignored)
38 *
39 * Returns the poll mask
40 */
41static unsigned int
42ecryptfs_miscdev_poll(struct file *file, poll_table *pt)
43{
44 struct ecryptfs_daemon *daemon = file->private_data;
45 unsigned int mask = 0;
46
47 mutex_lock(&daemon->mux);
48 if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
49 printk(KERN_WARNING "%s: Attempt to poll on zombified "
50 "daemon\n", __func__);
51 goto out_unlock_daemon;
52 }
53 if (daemon->flags & ECRYPTFS_DAEMON_IN_READ)
54 goto out_unlock_daemon;
55 if (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)
56 goto out_unlock_daemon;
57 daemon->flags |= ECRYPTFS_DAEMON_IN_POLL;
58 mutex_unlock(&daemon->mux);
59 poll_wait(file, &daemon->wait, pt);
60 mutex_lock(&daemon->mux);
61 if (!list_empty(&daemon->msg_ctx_out_queue))
62 mask |= POLLIN | POLLRDNORM;
63out_unlock_daemon:
64 daemon->flags &= ~ECRYPTFS_DAEMON_IN_POLL;
65 mutex_unlock(&daemon->mux);
66 return mask;
67}
68
69/**
70 * ecryptfs_miscdev_open
71 * @inode: inode of miscdev handle (ignored)
72 * @file: file for miscdev handle
73 *
74 * Returns zero on success; non-zero otherwise
75 */
76static int
77ecryptfs_miscdev_open(struct inode *inode, struct file *file)
78{
79 struct ecryptfs_daemon *daemon = NULL;
80 int rc;
81
82 mutex_lock(&ecryptfs_daemon_hash_mux);
83 rc = ecryptfs_find_daemon_by_euid(&daemon);
84 if (!rc) {
85 rc = -EINVAL;
86 goto out_unlock_daemon_list;
87 }
88 rc = ecryptfs_spawn_daemon(&daemon, file);
89 if (rc) {
90 printk(KERN_ERR "%s: Error attempting to spawn daemon; "
91 "rc = [%d]\n", __func__, rc);
92 goto out_unlock_daemon_list;
93 }
94 mutex_lock(&daemon->mux);
95 if (daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN) {
96 rc = -EBUSY;
97 goto out_unlock_daemon;
98 }
99 daemon->flags |= ECRYPTFS_DAEMON_MISCDEV_OPEN;
100 file->private_data = daemon;
101 atomic_inc(&ecryptfs_num_miscdev_opens);
102out_unlock_daemon:
103 mutex_unlock(&daemon->mux);
104out_unlock_daemon_list:
105 mutex_unlock(&ecryptfs_daemon_hash_mux);
106 return rc;
107}
108
109/**
110 * ecryptfs_miscdev_release
111 * @inode: inode of fs/ecryptfs/euid handle (ignored)
112 * @file: file for fs/ecryptfs/euid handle
113 *
114 * This keeps the daemon registered until the daemon sends another
115 * ioctl to fs/ecryptfs/ctl or until the kernel module unregisters.
116 *
117 * Returns zero on success; non-zero otherwise
118 */
119static int
120ecryptfs_miscdev_release(struct inode *inode, struct file *file)
121{
122 struct ecryptfs_daemon *daemon = file->private_data;
123 int rc;
124
125 mutex_lock(&daemon->mux);
126 BUG_ON(!(daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN));
127 daemon->flags &= ~ECRYPTFS_DAEMON_MISCDEV_OPEN;
128 atomic_dec(&ecryptfs_num_miscdev_opens);
129 mutex_unlock(&daemon->mux);
130
131 mutex_lock(&ecryptfs_daemon_hash_mux);
132 rc = ecryptfs_exorcise_daemon(daemon);
133 mutex_unlock(&ecryptfs_daemon_hash_mux);
134 if (rc) {
135 printk(KERN_CRIT "%s: Fatal error whilst attempting to "
136 "shut down daemon; rc = [%d]. Please report this "
137 "bug.\n", __func__, rc);
138 BUG();
139 }
140 return rc;
141}
142
143/**
144 * ecryptfs_send_miscdev
145 * @data: Data to send to daemon; may be NULL
146 * @data_size: Amount of data to send to daemon
147 * @msg_ctx: Message context, which is used to handle the reply. If
148 * this is NULL, then we do not expect a reply.
149 * @msg_type: Type of message
150 * @msg_flags: Flags for message
151 * @daemon: eCryptfs daemon object
152 *
153 * Add msg_ctx to queue and then, if it exists, notify the blocked
154 * miscdevess about the data being available. Must be called with
155 * ecryptfs_daemon_hash_mux held.
156 *
157 * Returns zero on success; non-zero otherwise
158 */
159int ecryptfs_send_miscdev(char *data, size_t data_size,
160 struct ecryptfs_msg_ctx *msg_ctx, u8 msg_type,
161 u16 msg_flags, struct ecryptfs_daemon *daemon)
162{
163 struct ecryptfs_message *msg;
164
165 msg = kmalloc((sizeof(*msg) + data_size), GFP_KERNEL);
166 if (!msg) {
167 printk(KERN_ERR "%s: Out of memory whilst attempting "
168 "to kmalloc(%zd, GFP_KERNEL)\n", __func__,
169 (sizeof(*msg) + data_size));
170 return -ENOMEM;
171 }
172
173 mutex_lock(&msg_ctx->mux);
174 msg_ctx->msg = msg;
175 msg_ctx->msg->index = msg_ctx->index;
176 msg_ctx->msg->data_len = data_size;
177 msg_ctx->type = msg_type;
178 memcpy(msg_ctx->msg->data, data, data_size);
179 msg_ctx->msg_size = (sizeof(*msg_ctx->msg) + data_size);
180 list_add_tail(&msg_ctx->daemon_out_list, &daemon->msg_ctx_out_queue);
181 mutex_unlock(&msg_ctx->mux);
182
183 mutex_lock(&daemon->mux);
184 daemon->num_queued_msg_ctx++;
185 wake_up_interruptible(&daemon->wait);
186 mutex_unlock(&daemon->mux);
187
188 return 0;
189}
190
191/*
192 * miscdevfs packet format:
193 * Octet 0: Type
194 * Octets 1-4: network byte order msg_ctx->counter
195 * Octets 5-N0: Size of struct ecryptfs_message to follow
196 * Octets N0-N1: struct ecryptfs_message (including data)
197 *
198 * Octets 5-N1 not written if the packet type does not include a message
199 */
200#define PKT_TYPE_SIZE 1
201#define PKT_CTR_SIZE 4
202#define MIN_NON_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE)
203#define MIN_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE \
204 + ECRYPTFS_MIN_PKT_LEN_SIZE)
205/* 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES comes from tag 65 packet format */
206#define MAX_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE \
207 + ECRYPTFS_MAX_PKT_LEN_SIZE \
208 + sizeof(struct ecryptfs_message) \
209 + 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES)
210#define PKT_TYPE_OFFSET 0
211#define PKT_CTR_OFFSET PKT_TYPE_SIZE
212#define PKT_LEN_OFFSET (PKT_TYPE_SIZE + PKT_CTR_SIZE)
213
214/**
215 * ecryptfs_miscdev_read - format and send message from queue
216 * @file: miscdevfs handle
217 * @buf: User buffer into which to copy the next message on the daemon queue
218 * @count: Amount of space available in @buf
219 * @ppos: Offset in file (ignored)
220 *
221 * Pulls the most recent message from the daemon queue, formats it for
222 * being sent via a miscdevfs handle, and copies it into @buf
223 *
224 * Returns the number of bytes copied into the user buffer
225 */
226static ssize_t
227ecryptfs_miscdev_read(struct file *file, char __user *buf, size_t count,
228 loff_t *ppos)
229{
230 struct ecryptfs_daemon *daemon = file->private_data;
231 struct ecryptfs_msg_ctx *msg_ctx;
232 size_t packet_length_size;
233 char packet_length[ECRYPTFS_MAX_PKT_LEN_SIZE];
234 size_t i;
235 size_t total_length;
236 int rc;
237
238 mutex_lock(&daemon->mux);
239 if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
240 rc = 0;
241 printk(KERN_WARNING "%s: Attempt to read from zombified "
242 "daemon\n", __func__);
243 goto out_unlock_daemon;
244 }
245 if (daemon->flags & ECRYPTFS_DAEMON_IN_READ) {
246 rc = 0;
247 goto out_unlock_daemon;
248 }
249 /* This daemon will not go away so long as this flag is set */
250 daemon->flags |= ECRYPTFS_DAEMON_IN_READ;
251check_list:
252 if (list_empty(&daemon->msg_ctx_out_queue)) {
253 mutex_unlock(&daemon->mux);
254 rc = wait_event_interruptible(
255 daemon->wait, !list_empty(&daemon->msg_ctx_out_queue));
256 mutex_lock(&daemon->mux);
257 if (rc < 0) {
258 rc = 0;
259 goto out_unlock_daemon;
260 }
261 }
262 if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
263 rc = 0;
264 goto out_unlock_daemon;
265 }
266 if (list_empty(&daemon->msg_ctx_out_queue)) {
267 /* Something else jumped in since the
268 * wait_event_interruptable() and removed the
269 * message from the queue; try again */
270 goto check_list;
271 }
272 msg_ctx = list_first_entry(&daemon->msg_ctx_out_queue,
273 struct ecryptfs_msg_ctx, daemon_out_list);
274 BUG_ON(!msg_ctx);
275 mutex_lock(&msg_ctx->mux);
276 if (msg_ctx->msg) {
277 rc = ecryptfs_write_packet_length(packet_length,
278 msg_ctx->msg_size,
279 &packet_length_size);
280 if (rc) {
281 rc = 0;
282 printk(KERN_WARNING "%s: Error writing packet length; "
283 "rc = [%d]\n", __func__, rc);
284 goto out_unlock_msg_ctx;
285 }
286 } else {
287 packet_length_size = 0;
288 msg_ctx->msg_size = 0;
289 }
290 total_length = (PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_length_size
291 + msg_ctx->msg_size);
292 if (count < total_length) {
293 rc = 0;
294 printk(KERN_WARNING "%s: Only given user buffer of "
295 "size [%zd], but we need [%zd] to read the "
296 "pending message\n", __func__, count, total_length);
297 goto out_unlock_msg_ctx;
298 }
299 rc = -EFAULT;
300 if (put_user(msg_ctx->type, buf))
301 goto out_unlock_msg_ctx;
302 if (put_user(cpu_to_be32(msg_ctx->counter),
303 (__be32 __user *)(&buf[PKT_CTR_OFFSET])))
304 goto out_unlock_msg_ctx;
305 i = PKT_TYPE_SIZE + PKT_CTR_SIZE;
306 if (msg_ctx->msg) {
307 if (copy_to_user(&buf[i], packet_length, packet_length_size))
308 goto out_unlock_msg_ctx;
309 i += packet_length_size;
310 if (copy_to_user(&buf[i], msg_ctx->msg, msg_ctx->msg_size))
311 goto out_unlock_msg_ctx;
312 i += msg_ctx->msg_size;
313 }
314 rc = i;
315 list_del(&msg_ctx->daemon_out_list);
316 kfree(msg_ctx->msg);
317 msg_ctx->msg = NULL;
318 /* We do not expect a reply from the userspace daemon for any
319 * message type other than ECRYPTFS_MSG_REQUEST */
320 if (msg_ctx->type != ECRYPTFS_MSG_REQUEST)
321 ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
322out_unlock_msg_ctx:
323 mutex_unlock(&msg_ctx->mux);
324out_unlock_daemon:
325 daemon->flags &= ~ECRYPTFS_DAEMON_IN_READ;
326 mutex_unlock(&daemon->mux);
327 return rc;
328}
329
330/**
331 * ecryptfs_miscdev_response - miscdevess response to message previously sent to daemon
332 * @data: Bytes comprising struct ecryptfs_message
333 * @data_size: sizeof(struct ecryptfs_message) + data len
334 * @seq: Sequence number for miscdev response packet
335 *
336 * Returns zero on success; non-zero otherwise
337 */
338static int ecryptfs_miscdev_response(struct ecryptfs_daemon *daemon, char *data,
339 size_t data_size, u32 seq)
340{
341 struct ecryptfs_message *msg = (struct ecryptfs_message *)data;
342 int rc;
343
344 if ((sizeof(*msg) + msg->data_len) != data_size) {
345 printk(KERN_WARNING "%s: (sizeof(*msg) + msg->data_len) = "
346 "[%zd]; data_size = [%zd]. Invalid packet.\n", __func__,
347 (sizeof(*msg) + msg->data_len), data_size);
348 rc = -EINVAL;
349 goto out;
350 }
351 rc = ecryptfs_process_response(daemon, msg, seq);
352 if (rc)
353 printk(KERN_ERR
354 "Error processing response message; rc = [%d]\n", rc);
355out:
356 return rc;
357}
358
359/**
360 * ecryptfs_miscdev_write - handle write to daemon miscdev handle
361 * @file: File for misc dev handle
362 * @buf: Buffer containing user data
363 * @count: Amount of data in @buf
364 * @ppos: Pointer to offset in file (ignored)
365 *
366 * Returns the number of bytes read from @buf
367 */
368static ssize_t
369ecryptfs_miscdev_write(struct file *file, const char __user *buf,
370 size_t count, loff_t *ppos)
371{
372 __be32 counter_nbo;
373 u32 seq;
374 size_t packet_size, packet_size_length;
375 char *data;
376 unsigned char packet_size_peek[ECRYPTFS_MAX_PKT_LEN_SIZE];
377 ssize_t rc;
378
379 if (count == 0) {
380 return 0;
381 } else if (count == MIN_NON_MSG_PKT_SIZE) {
382 /* Likely a harmless MSG_HELO or MSG_QUIT - no packet length */
383 goto memdup;
384 } else if (count < MIN_MSG_PKT_SIZE || count > MAX_MSG_PKT_SIZE) {
385 printk(KERN_WARNING "%s: Acceptable packet size range is "
386 "[%d-%zu], but amount of data written is [%zu].",
387 __func__, MIN_MSG_PKT_SIZE, MAX_MSG_PKT_SIZE, count);
388 return -EINVAL;
389 }
390
391 if (copy_from_user(packet_size_peek, &buf[PKT_LEN_OFFSET],
392 sizeof(packet_size_peek))) {
393 printk(KERN_WARNING "%s: Error while inspecting packet size\n",
394 __func__);
395 return -EFAULT;
396 }
397
398 rc = ecryptfs_parse_packet_length(packet_size_peek, &packet_size,
399 &packet_size_length);
400 if (rc) {
401 printk(KERN_WARNING "%s: Error parsing packet length; "
402 "rc = [%zd]\n", __func__, rc);
403 return rc;
404 }
405
406 if ((PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_size_length + packet_size)
407 != count) {
408 printk(KERN_WARNING "%s: Invalid packet size [%zu]\n", __func__,
409 packet_size);
410 return -EINVAL;
411 }
412
413memdup:
414 data = memdup_user(buf, count);
415 if (IS_ERR(data)) {
416 printk(KERN_ERR "%s: memdup_user returned error [%ld]\n",
417 __func__, PTR_ERR(data));
418 return PTR_ERR(data);
419 }
420 switch (data[PKT_TYPE_OFFSET]) {
421 case ECRYPTFS_MSG_RESPONSE:
422 if (count < (MIN_MSG_PKT_SIZE
423 + sizeof(struct ecryptfs_message))) {
424 printk(KERN_WARNING "%s: Minimum acceptable packet "
425 "size is [%zd], but amount of data written is "
426 "only [%zd]. Discarding response packet.\n",
427 __func__,
428 (MIN_MSG_PKT_SIZE
429 + sizeof(struct ecryptfs_message)), count);
430 rc = -EINVAL;
431 goto out_free;
432 }
433 memcpy(&counter_nbo, &data[PKT_CTR_OFFSET], PKT_CTR_SIZE);
434 seq = be32_to_cpu(counter_nbo);
435 rc = ecryptfs_miscdev_response(file->private_data,
436 &data[PKT_LEN_OFFSET + packet_size_length],
437 packet_size, seq);
438 if (rc) {
439 printk(KERN_WARNING "%s: Failed to deliver miscdev "
440 "response to requesting operation; rc = [%zd]\n",
441 __func__, rc);
442 goto out_free;
443 }
444 break;
445 case ECRYPTFS_MSG_HELO:
446 case ECRYPTFS_MSG_QUIT:
447 break;
448 default:
449 ecryptfs_printk(KERN_WARNING, "Dropping miscdev "
450 "message of unrecognized type [%d]\n",
451 data[0]);
452 rc = -EINVAL;
453 goto out_free;
454 }
455 rc = count;
456out_free:
457 kfree(data);
458 return rc;
459}
460
461
462static const struct file_operations ecryptfs_miscdev_fops = {
463 .owner = THIS_MODULE,
464 .open = ecryptfs_miscdev_open,
465 .poll = ecryptfs_miscdev_poll,
466 .read = ecryptfs_miscdev_read,
467 .write = ecryptfs_miscdev_write,
468 .release = ecryptfs_miscdev_release,
469 .llseek = noop_llseek,
470};
471
472static struct miscdevice ecryptfs_miscdev = {
473 .minor = MISC_DYNAMIC_MINOR,
474 .name = "ecryptfs",
475 .fops = &ecryptfs_miscdev_fops
476};
477
478/**
479 * ecryptfs_init_ecryptfs_miscdev
480 *
481 * Messages sent to the userspace daemon from the kernel are placed on
482 * a queue associated with the daemon. The next read against the
483 * miscdev handle by that daemon will return the oldest message placed
484 * on the message queue for the daemon.
485 *
486 * Returns zero on success; non-zero otherwise
487 */
488int __init ecryptfs_init_ecryptfs_miscdev(void)
489{
490 int rc;
491
492 atomic_set(&ecryptfs_num_miscdev_opens, 0);
493 rc = misc_register(&ecryptfs_miscdev);
494 if (rc)
495 printk(KERN_ERR "%s: Failed to register miscellaneous device "
496 "for communications with userspace daemons; rc = [%d]\n",
497 __func__, rc);
498 return rc;
499}
500
501/**
502 * ecryptfs_destroy_ecryptfs_miscdev
503 *
504 * All of the daemons must be exorcised prior to calling this
505 * function.
506 */
507void ecryptfs_destroy_ecryptfs_miscdev(void)
508{
509 BUG_ON(atomic_read(&ecryptfs_num_miscdev_opens) != 0);
510 misc_deregister(&ecryptfs_miscdev);
511}
1/**
2 * eCryptfs: Linux filesystem encryption layer
3 *
4 * Copyright (C) 2008 International Business Machines Corp.
5 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
6 *
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.
10 *
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.
15 *
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
19 * 02111-1307, USA.
20 */
21
22#include <linux/fs.h>
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"
31
32static atomic_t ecryptfs_num_miscdev_opens;
33
34/**
35 * ecryptfs_miscdev_poll
36 * @file: dev file
37 * @pt: dev poll table (ignored)
38 *
39 * Returns the poll mask
40 */
41static __poll_t
42ecryptfs_miscdev_poll(struct file *file, poll_table *pt)
43{
44 struct ecryptfs_daemon *daemon = file->private_data;
45 __poll_t mask = 0;
46
47 mutex_lock(&daemon->mux);
48 if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
49 printk(KERN_WARNING "%s: Attempt to poll on zombified "
50 "daemon\n", __func__);
51 goto out_unlock_daemon;
52 }
53 if (daemon->flags & ECRYPTFS_DAEMON_IN_READ)
54 goto out_unlock_daemon;
55 if (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)
56 goto out_unlock_daemon;
57 daemon->flags |= ECRYPTFS_DAEMON_IN_POLL;
58 mutex_unlock(&daemon->mux);
59 poll_wait(file, &daemon->wait, pt);
60 mutex_lock(&daemon->mux);
61 if (!list_empty(&daemon->msg_ctx_out_queue))
62 mask |= EPOLLIN | EPOLLRDNORM;
63out_unlock_daemon:
64 daemon->flags &= ~ECRYPTFS_DAEMON_IN_POLL;
65 mutex_unlock(&daemon->mux);
66 return mask;
67}
68
69/**
70 * ecryptfs_miscdev_open
71 * @inode: inode of miscdev handle (ignored)
72 * @file: file for miscdev handle
73 *
74 * Returns zero on success; non-zero otherwise
75 */
76static int
77ecryptfs_miscdev_open(struct inode *inode, struct file *file)
78{
79 struct ecryptfs_daemon *daemon = NULL;
80 int rc;
81
82 mutex_lock(&ecryptfs_daemon_hash_mux);
83 rc = ecryptfs_find_daemon_by_euid(&daemon);
84 if (!rc) {
85 rc = -EINVAL;
86 goto out_unlock_daemon_list;
87 }
88 rc = ecryptfs_spawn_daemon(&daemon, file);
89 if (rc) {
90 printk(KERN_ERR "%s: Error attempting to spawn daemon; "
91 "rc = [%d]\n", __func__, rc);
92 goto out_unlock_daemon_list;
93 }
94 mutex_lock(&daemon->mux);
95 if (daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN) {
96 rc = -EBUSY;
97 goto out_unlock_daemon;
98 }
99 daemon->flags |= ECRYPTFS_DAEMON_MISCDEV_OPEN;
100 file->private_data = daemon;
101 atomic_inc(&ecryptfs_num_miscdev_opens);
102out_unlock_daemon:
103 mutex_unlock(&daemon->mux);
104out_unlock_daemon_list:
105 mutex_unlock(&ecryptfs_daemon_hash_mux);
106 return rc;
107}
108
109/**
110 * ecryptfs_miscdev_release
111 * @inode: inode of fs/ecryptfs/euid handle (ignored)
112 * @file: file for fs/ecryptfs/euid handle
113 *
114 * This keeps the daemon registered until the daemon sends another
115 * ioctl to fs/ecryptfs/ctl or until the kernel module unregisters.
116 *
117 * Returns zero on success; non-zero otherwise
118 */
119static int
120ecryptfs_miscdev_release(struct inode *inode, struct file *file)
121{
122 struct ecryptfs_daemon *daemon = file->private_data;
123 int rc;
124
125 mutex_lock(&daemon->mux);
126 BUG_ON(!(daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN));
127 daemon->flags &= ~ECRYPTFS_DAEMON_MISCDEV_OPEN;
128 atomic_dec(&ecryptfs_num_miscdev_opens);
129 mutex_unlock(&daemon->mux);
130
131 mutex_lock(&ecryptfs_daemon_hash_mux);
132 rc = ecryptfs_exorcise_daemon(daemon);
133 mutex_unlock(&ecryptfs_daemon_hash_mux);
134 if (rc) {
135 printk(KERN_CRIT "%s: Fatal error whilst attempting to "
136 "shut down daemon; rc = [%d]. Please report this "
137 "bug.\n", __func__, rc);
138 BUG();
139 }
140 return rc;
141}
142
143/**
144 * ecryptfs_send_miscdev
145 * @data: Data to send to daemon; may be NULL
146 * @data_size: Amount of data to send to daemon
147 * @msg_ctx: Message context, which is used to handle the reply. If
148 * this is NULL, then we do not expect a reply.
149 * @msg_type: Type of message
150 * @msg_flags: Flags for message
151 * @daemon: eCryptfs daemon object
152 *
153 * Add msg_ctx to queue and then, if it exists, notify the blocked
154 * miscdevess about the data being available. Must be called with
155 * ecryptfs_daemon_hash_mux held.
156 *
157 * Returns zero on success; non-zero otherwise
158 */
159int ecryptfs_send_miscdev(char *data, size_t data_size,
160 struct ecryptfs_msg_ctx *msg_ctx, u8 msg_type,
161 u16 msg_flags, struct ecryptfs_daemon *daemon)
162{
163 struct ecryptfs_message *msg;
164
165 msg = kmalloc((sizeof(*msg) + data_size), GFP_KERNEL);
166 if (!msg)
167 return -ENOMEM;
168
169 mutex_lock(&msg_ctx->mux);
170 msg_ctx->msg = msg;
171 msg_ctx->msg->index = msg_ctx->index;
172 msg_ctx->msg->data_len = data_size;
173 msg_ctx->type = msg_type;
174 memcpy(msg_ctx->msg->data, data, data_size);
175 msg_ctx->msg_size = (sizeof(*msg_ctx->msg) + data_size);
176 list_add_tail(&msg_ctx->daemon_out_list, &daemon->msg_ctx_out_queue);
177 mutex_unlock(&msg_ctx->mux);
178
179 mutex_lock(&daemon->mux);
180 daemon->num_queued_msg_ctx++;
181 wake_up_interruptible(&daemon->wait);
182 mutex_unlock(&daemon->mux);
183
184 return 0;
185}
186
187/*
188 * miscdevfs packet format:
189 * Octet 0: Type
190 * Octets 1-4: network byte order msg_ctx->counter
191 * Octets 5-N0: Size of struct ecryptfs_message to follow
192 * Octets N0-N1: struct ecryptfs_message (including data)
193 *
194 * Octets 5-N1 not written if the packet type does not include a message
195 */
196#define PKT_TYPE_SIZE 1
197#define PKT_CTR_SIZE 4
198#define MIN_NON_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE)
199#define MIN_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE \
200 + ECRYPTFS_MIN_PKT_LEN_SIZE)
201/* 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES comes from tag 65 packet format */
202#define MAX_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE \
203 + ECRYPTFS_MAX_PKT_LEN_SIZE \
204 + sizeof(struct ecryptfs_message) \
205 + 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES)
206#define PKT_TYPE_OFFSET 0
207#define PKT_CTR_OFFSET PKT_TYPE_SIZE
208#define PKT_LEN_OFFSET (PKT_TYPE_SIZE + PKT_CTR_SIZE)
209
210/**
211 * ecryptfs_miscdev_read - format and send message from queue
212 * @file: miscdevfs handle
213 * @buf: User buffer into which to copy the next message on the daemon queue
214 * @count: Amount of space available in @buf
215 * @ppos: Offset in file (ignored)
216 *
217 * Pulls the most recent message from the daemon queue, formats it for
218 * being sent via a miscdevfs handle, and copies it into @buf
219 *
220 * Returns the number of bytes copied into the user buffer
221 */
222static ssize_t
223ecryptfs_miscdev_read(struct file *file, char __user *buf, size_t count,
224 loff_t *ppos)
225{
226 struct ecryptfs_daemon *daemon = file->private_data;
227 struct ecryptfs_msg_ctx *msg_ctx;
228 size_t packet_length_size;
229 char packet_length[ECRYPTFS_MAX_PKT_LEN_SIZE];
230 size_t i;
231 size_t total_length;
232 int rc;
233
234 mutex_lock(&daemon->mux);
235 if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
236 rc = 0;
237 printk(KERN_WARNING "%s: Attempt to read from zombified "
238 "daemon\n", __func__);
239 goto out_unlock_daemon;
240 }
241 if (daemon->flags & ECRYPTFS_DAEMON_IN_READ) {
242 rc = 0;
243 goto out_unlock_daemon;
244 }
245 /* This daemon will not go away so long as this flag is set */
246 daemon->flags |= ECRYPTFS_DAEMON_IN_READ;
247check_list:
248 if (list_empty(&daemon->msg_ctx_out_queue)) {
249 mutex_unlock(&daemon->mux);
250 rc = wait_event_interruptible(
251 daemon->wait, !list_empty(&daemon->msg_ctx_out_queue));
252 mutex_lock(&daemon->mux);
253 if (rc < 0) {
254 rc = 0;
255 goto out_unlock_daemon;
256 }
257 }
258 if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
259 rc = 0;
260 goto out_unlock_daemon;
261 }
262 if (list_empty(&daemon->msg_ctx_out_queue)) {
263 /* Something else jumped in since the
264 * wait_event_interruptable() and removed the
265 * message from the queue; try again */
266 goto check_list;
267 }
268 msg_ctx = list_first_entry(&daemon->msg_ctx_out_queue,
269 struct ecryptfs_msg_ctx, daemon_out_list);
270 BUG_ON(!msg_ctx);
271 mutex_lock(&msg_ctx->mux);
272 if (msg_ctx->msg) {
273 rc = ecryptfs_write_packet_length(packet_length,
274 msg_ctx->msg_size,
275 &packet_length_size);
276 if (rc) {
277 rc = 0;
278 printk(KERN_WARNING "%s: Error writing packet length; "
279 "rc = [%d]\n", __func__, rc);
280 goto out_unlock_msg_ctx;
281 }
282 } else {
283 packet_length_size = 0;
284 msg_ctx->msg_size = 0;
285 }
286 total_length = (PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_length_size
287 + msg_ctx->msg_size);
288 if (count < total_length) {
289 rc = 0;
290 printk(KERN_WARNING "%s: Only given user buffer of "
291 "size [%zd], but we need [%zd] to read the "
292 "pending message\n", __func__, count, total_length);
293 goto out_unlock_msg_ctx;
294 }
295 rc = -EFAULT;
296 if (put_user(msg_ctx->type, buf))
297 goto out_unlock_msg_ctx;
298 if (put_user(cpu_to_be32(msg_ctx->counter),
299 (__be32 __user *)(&buf[PKT_CTR_OFFSET])))
300 goto out_unlock_msg_ctx;
301 i = PKT_TYPE_SIZE + PKT_CTR_SIZE;
302 if (msg_ctx->msg) {
303 if (copy_to_user(&buf[i], packet_length, packet_length_size))
304 goto out_unlock_msg_ctx;
305 i += packet_length_size;
306 if (copy_to_user(&buf[i], msg_ctx->msg, msg_ctx->msg_size))
307 goto out_unlock_msg_ctx;
308 i += msg_ctx->msg_size;
309 }
310 rc = i;
311 list_del(&msg_ctx->daemon_out_list);
312 kfree(msg_ctx->msg);
313 msg_ctx->msg = NULL;
314 /* We do not expect a reply from the userspace daemon for any
315 * message type other than ECRYPTFS_MSG_REQUEST */
316 if (msg_ctx->type != ECRYPTFS_MSG_REQUEST)
317 ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
318out_unlock_msg_ctx:
319 mutex_unlock(&msg_ctx->mux);
320out_unlock_daemon:
321 daemon->flags &= ~ECRYPTFS_DAEMON_IN_READ;
322 mutex_unlock(&daemon->mux);
323 return rc;
324}
325
326/**
327 * ecryptfs_miscdev_response - miscdevess response to message previously sent to daemon
328 * @data: Bytes comprising struct ecryptfs_message
329 * @data_size: sizeof(struct ecryptfs_message) + data len
330 * @seq: Sequence number for miscdev response packet
331 *
332 * Returns zero on success; non-zero otherwise
333 */
334static int ecryptfs_miscdev_response(struct ecryptfs_daemon *daemon, char *data,
335 size_t data_size, u32 seq)
336{
337 struct ecryptfs_message *msg = (struct ecryptfs_message *)data;
338 int rc;
339
340 if ((sizeof(*msg) + msg->data_len) != data_size) {
341 printk(KERN_WARNING "%s: (sizeof(*msg) + msg->data_len) = "
342 "[%zd]; data_size = [%zd]. Invalid packet.\n", __func__,
343 (sizeof(*msg) + msg->data_len), data_size);
344 rc = -EINVAL;
345 goto out;
346 }
347 rc = ecryptfs_process_response(daemon, msg, seq);
348 if (rc)
349 printk(KERN_ERR
350 "Error processing response message; rc = [%d]\n", rc);
351out:
352 return rc;
353}
354
355/**
356 * ecryptfs_miscdev_write - handle write to daemon miscdev handle
357 * @file: File for misc dev handle
358 * @buf: Buffer containing user data
359 * @count: Amount of data in @buf
360 * @ppos: Pointer to offset in file (ignored)
361 *
362 * Returns the number of bytes read from @buf
363 */
364static ssize_t
365ecryptfs_miscdev_write(struct file *file, const char __user *buf,
366 size_t count, loff_t *ppos)
367{
368 __be32 counter_nbo;
369 u32 seq;
370 size_t packet_size, packet_size_length;
371 char *data;
372 unsigned char packet_size_peek[ECRYPTFS_MAX_PKT_LEN_SIZE];
373 ssize_t rc;
374
375 if (count == 0) {
376 return 0;
377 } else if (count == MIN_NON_MSG_PKT_SIZE) {
378 /* Likely a harmless MSG_HELO or MSG_QUIT - no packet length */
379 goto memdup;
380 } else if (count < MIN_MSG_PKT_SIZE || count > MAX_MSG_PKT_SIZE) {
381 printk(KERN_WARNING "%s: Acceptable packet size range is "
382 "[%d-%zu], but amount of data written is [%zu].\n",
383 __func__, MIN_MSG_PKT_SIZE, MAX_MSG_PKT_SIZE, count);
384 return -EINVAL;
385 }
386
387 if (copy_from_user(packet_size_peek, &buf[PKT_LEN_OFFSET],
388 sizeof(packet_size_peek))) {
389 printk(KERN_WARNING "%s: Error while inspecting packet size\n",
390 __func__);
391 return -EFAULT;
392 }
393
394 rc = ecryptfs_parse_packet_length(packet_size_peek, &packet_size,
395 &packet_size_length);
396 if (rc) {
397 printk(KERN_WARNING "%s: Error parsing packet length; "
398 "rc = [%zd]\n", __func__, rc);
399 return rc;
400 }
401
402 if ((PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_size_length + packet_size)
403 != count) {
404 printk(KERN_WARNING "%s: Invalid packet size [%zu]\n", __func__,
405 packet_size);
406 return -EINVAL;
407 }
408
409memdup:
410 data = memdup_user(buf, count);
411 if (IS_ERR(data)) {
412 printk(KERN_ERR "%s: memdup_user returned error [%ld]\n",
413 __func__, PTR_ERR(data));
414 return PTR_ERR(data);
415 }
416 switch (data[PKT_TYPE_OFFSET]) {
417 case ECRYPTFS_MSG_RESPONSE:
418 if (count < (MIN_MSG_PKT_SIZE
419 + sizeof(struct ecryptfs_message))) {
420 printk(KERN_WARNING "%s: Minimum acceptable packet "
421 "size is [%zd], but amount of data written is "
422 "only [%zd]. Discarding response packet.\n",
423 __func__,
424 (MIN_MSG_PKT_SIZE
425 + sizeof(struct ecryptfs_message)), count);
426 rc = -EINVAL;
427 goto out_free;
428 }
429 memcpy(&counter_nbo, &data[PKT_CTR_OFFSET], PKT_CTR_SIZE);
430 seq = be32_to_cpu(counter_nbo);
431 rc = ecryptfs_miscdev_response(file->private_data,
432 &data[PKT_LEN_OFFSET + packet_size_length],
433 packet_size, seq);
434 if (rc) {
435 printk(KERN_WARNING "%s: Failed to deliver miscdev "
436 "response to requesting operation; rc = [%zd]\n",
437 __func__, rc);
438 goto out_free;
439 }
440 break;
441 case ECRYPTFS_MSG_HELO:
442 case ECRYPTFS_MSG_QUIT:
443 break;
444 default:
445 ecryptfs_printk(KERN_WARNING, "Dropping miscdev "
446 "message of unrecognized type [%d]\n",
447 data[0]);
448 rc = -EINVAL;
449 goto out_free;
450 }
451 rc = count;
452out_free:
453 kfree(data);
454 return rc;
455}
456
457
458static const struct file_operations ecryptfs_miscdev_fops = {
459 .owner = THIS_MODULE,
460 .open = ecryptfs_miscdev_open,
461 .poll = ecryptfs_miscdev_poll,
462 .read = ecryptfs_miscdev_read,
463 .write = ecryptfs_miscdev_write,
464 .release = ecryptfs_miscdev_release,
465 .llseek = noop_llseek,
466};
467
468static struct miscdevice ecryptfs_miscdev = {
469 .minor = MISC_DYNAMIC_MINOR,
470 .name = "ecryptfs",
471 .fops = &ecryptfs_miscdev_fops
472};
473
474/**
475 * ecryptfs_init_ecryptfs_miscdev
476 *
477 * Messages sent to the userspace daemon from the kernel are placed on
478 * a queue associated with the daemon. The next read against the
479 * miscdev handle by that daemon will return the oldest message placed
480 * on the message queue for the daemon.
481 *
482 * Returns zero on success; non-zero otherwise
483 */
484int __init ecryptfs_init_ecryptfs_miscdev(void)
485{
486 int rc;
487
488 atomic_set(&ecryptfs_num_miscdev_opens, 0);
489 rc = misc_register(&ecryptfs_miscdev);
490 if (rc)
491 printk(KERN_ERR "%s: Failed to register miscellaneous device "
492 "for communications with userspace daemons; rc = [%d]\n",
493 __func__, rc);
494 return rc;
495}
496
497/**
498 * ecryptfs_destroy_ecryptfs_miscdev
499 *
500 * All of the daemons must be exorcised prior to calling this
501 * function.
502 */
503void ecryptfs_destroy_ecryptfs_miscdev(void)
504{
505 BUG_ON(atomic_read(&ecryptfs_num_miscdev_opens) != 0);
506 misc_deregister(&ecryptfs_miscdev);
507}