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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/wait.h> | |
28 | #include <linux/module.h> | |
29 | #include "ecryptfs_kernel.h" | |
30 | ||
31 | static atomic_t ecryptfs_num_miscdev_opens; | |
32 | ||
33 | /** | |
34 | * ecryptfs_miscdev_poll | |
35 | * @file: dev file (ignored) | |
36 | * @pt: dev poll table (ignored) | |
37 | * | |
38 | * Returns the poll mask | |
39 | */ | |
40 | static unsigned int | |
41 | ecryptfs_miscdev_poll(struct file *file, poll_table *pt) | |
42 | { | |
43 | struct ecryptfs_daemon *daemon; | |
44 | unsigned int mask = 0; | |
45 | int rc; | |
46 | ||
47 | mutex_lock(&ecryptfs_daemon_hash_mux); | |
48 | /* TODO: Just use file->private_data? */ | |
49 | rc = ecryptfs_find_daemon_by_euid(&daemon, current->euid); | |
50 | BUG_ON(rc || !daemon); | |
51 | mutex_lock(&daemon->mux); | |
52 | mutex_unlock(&ecryptfs_daemon_hash_mux); | |
53 | if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) { | |
54 | printk(KERN_WARNING "%s: Attempt to poll on zombified " | |
55 | "daemon\n", __func__); | |
56 | goto out_unlock_daemon; | |
57 | } | |
58 | if (daemon->flags & ECRYPTFS_DAEMON_IN_READ) | |
59 | goto out_unlock_daemon; | |
60 | if (daemon->flags & ECRYPTFS_DAEMON_IN_POLL) | |
61 | goto out_unlock_daemon; | |
62 | daemon->flags |= ECRYPTFS_DAEMON_IN_POLL; | |
63 | mutex_unlock(&daemon->mux); | |
64 | poll_wait(file, &daemon->wait, pt); | |
65 | mutex_lock(&daemon->mux); | |
66 | if (!list_empty(&daemon->msg_ctx_out_queue)) | |
67 | mask |= POLLIN | POLLRDNORM; | |
68 | out_unlock_daemon: | |
69 | daemon->flags &= ~ECRYPTFS_DAEMON_IN_POLL; | |
70 | mutex_unlock(&daemon->mux); | |
71 | return mask; | |
72 | } | |
73 | ||
74 | /** | |
75 | * ecryptfs_miscdev_open | |
76 | * @inode: inode of miscdev handle (ignored) | |
77 | * @file: file for miscdev handle (ignored) | |
78 | * | |
79 | * Returns zero on success; non-zero otherwise | |
80 | */ | |
81 | static int | |
82 | ecryptfs_miscdev_open(struct inode *inode, struct file *file) | |
83 | { | |
84 | struct ecryptfs_daemon *daemon = NULL; | |
85 | int rc; | |
86 | ||
87 | mutex_lock(&ecryptfs_daemon_hash_mux); | |
88 | rc = try_module_get(THIS_MODULE); | |
89 | if (rc == 0) { | |
90 | rc = -EIO; | |
91 | printk(KERN_ERR "%s: Error attempting to increment module use " | |
92 | "count; rc = [%d]\n", __func__, rc); | |
93 | goto out_unlock_daemon_list; | |
94 | } | |
95 | rc = ecryptfs_find_daemon_by_euid(&daemon, current->euid); | |
96 | if (rc || !daemon) { | |
97 | rc = ecryptfs_spawn_daemon(&daemon, current->euid, | |
98 | current->pid); | |
99 | if (rc) { | |
100 | printk(KERN_ERR "%s: Error attempting to spawn daemon; " | |
101 | "rc = [%d]\n", __func__, rc); | |
102 | goto out_module_put_unlock_daemon_list; | |
103 | } | |
104 | } | |
105 | mutex_lock(&daemon->mux); | |
106 | if (daemon->pid != current->pid) { | |
107 | rc = -EINVAL; | |
108 | printk(KERN_ERR "%s: pid [%d] has registered with euid [%d], " | |
109 | "but pid [%d] has attempted to open the handle " | |
110 | "instead\n", __func__, daemon->pid, daemon->euid, | |
111 | current->pid); | |
112 | goto out_unlock_daemon; | |
113 | } | |
114 | if (daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN) { | |
115 | rc = -EBUSY; | |
116 | printk(KERN_ERR "%s: Miscellaneous device handle may only be " | |
117 | "opened once per daemon; pid [%d] already has this " | |
118 | "handle open\n", __func__, daemon->pid); | |
119 | goto out_unlock_daemon; | |
120 | } | |
121 | daemon->flags |= ECRYPTFS_DAEMON_MISCDEV_OPEN; | |
122 | atomic_inc(&ecryptfs_num_miscdev_opens); | |
123 | out_unlock_daemon: | |
124 | mutex_unlock(&daemon->mux); | |
125 | out_module_put_unlock_daemon_list: | |
126 | if (rc) | |
127 | module_put(THIS_MODULE); | |
128 | out_unlock_daemon_list: | |
129 | mutex_unlock(&ecryptfs_daemon_hash_mux); | |
130 | return rc; | |
131 | } | |
132 | ||
133 | /** | |
134 | * ecryptfs_miscdev_release | |
135 | * @inode: inode of fs/ecryptfs/euid handle (ignored) | |
136 | * @file: file for fs/ecryptfs/euid handle (ignored) | |
137 | * | |
138 | * This keeps the daemon registered until the daemon sends another | |
139 | * ioctl to fs/ecryptfs/ctl or until the kernel module unregisters. | |
140 | * | |
141 | * Returns zero on success; non-zero otherwise | |
142 | */ | |
143 | static int | |
144 | ecryptfs_miscdev_release(struct inode *inode, struct file *file) | |
145 | { | |
146 | struct ecryptfs_daemon *daemon = NULL; | |
147 | int rc; | |
148 | ||
149 | mutex_lock(&ecryptfs_daemon_hash_mux); | |
150 | rc = ecryptfs_find_daemon_by_euid(&daemon, current->euid); | |
151 | BUG_ON(rc || !daemon); | |
152 | mutex_lock(&daemon->mux); | |
153 | BUG_ON(daemon->pid != current->pid); | |
154 | BUG_ON(!(daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN)); | |
155 | daemon->flags &= ~ECRYPTFS_DAEMON_MISCDEV_OPEN; | |
156 | atomic_dec(&ecryptfs_num_miscdev_opens); | |
157 | mutex_unlock(&daemon->mux); | |
158 | rc = ecryptfs_exorcise_daemon(daemon); | |
159 | if (rc) { | |
160 | printk(KERN_CRIT "%s: Fatal error whilst attempting to " | |
161 | "shut down daemon; rc = [%d]. Please report this " | |
162 | "bug.\n", __func__, rc); | |
163 | BUG(); | |
164 | } | |
165 | module_put(THIS_MODULE); | |
166 | mutex_unlock(&ecryptfs_daemon_hash_mux); | |
167 | return rc; | |
168 | } | |
169 | ||
170 | /** | |
171 | * ecryptfs_send_miscdev | |
172 | * @data: Data to send to daemon; may be NULL | |
173 | * @data_size: Amount of data to send to daemon | |
174 | * @msg_ctx: Message context, which is used to handle the reply. If | |
175 | * this is NULL, then we do not expect a reply. | |
176 | * @msg_type: Type of message | |
177 | * @msg_flags: Flags for message | |
178 | * @daemon: eCryptfs daemon object | |
179 | * | |
180 | * Add msg_ctx to queue and then, if it exists, notify the blocked | |
181 | * miscdevess about the data being available. Must be called with | |
182 | * ecryptfs_daemon_hash_mux held. | |
183 | * | |
184 | * Returns zero on success; non-zero otherwise | |
185 | */ | |
186 | int ecryptfs_send_miscdev(char *data, size_t data_size, | |
187 | struct ecryptfs_msg_ctx *msg_ctx, u8 msg_type, | |
188 | u16 msg_flags, struct ecryptfs_daemon *daemon) | |
189 | { | |
190 | int rc = 0; | |
191 | ||
192 | mutex_lock(&msg_ctx->mux); | |
193 | if (data) { | |
194 | msg_ctx->msg = kmalloc((sizeof(*msg_ctx->msg) + data_size), | |
195 | GFP_KERNEL); | |
196 | if (!msg_ctx->msg) { | |
197 | rc = -ENOMEM; | |
198 | printk(KERN_ERR "%s: Out of memory whilst attempting " | |
199 | "to kmalloc(%d, GFP_KERNEL)\n", __func__, | |
200 | (sizeof(*msg_ctx->msg) + data_size)); | |
201 | goto out_unlock; | |
202 | } | |
203 | } else | |
204 | msg_ctx->msg = NULL; | |
205 | msg_ctx->msg->index = msg_ctx->index; | |
206 | msg_ctx->msg->data_len = data_size; | |
207 | msg_ctx->type = msg_type; | |
208 | if (data) { | |
209 | memcpy(msg_ctx->msg->data, data, data_size); | |
210 | msg_ctx->msg_size = (sizeof(*msg_ctx->msg) + data_size); | |
211 | } else | |
212 | msg_ctx->msg_size = 0; | |
213 | mutex_lock(&daemon->mux); | |
214 | list_add_tail(&msg_ctx->daemon_out_list, &daemon->msg_ctx_out_queue); | |
215 | daemon->num_queued_msg_ctx++; | |
216 | wake_up_interruptible(&daemon->wait); | |
217 | mutex_unlock(&daemon->mux); | |
218 | out_unlock: | |
219 | mutex_unlock(&msg_ctx->mux); | |
220 | return rc; | |
221 | } | |
222 | ||
223 | /** | |
224 | * ecryptfs_miscdev_read - format and send message from queue | |
225 | * @file: fs/ecryptfs/euid miscdevfs handle (ignored) | |
226 | * @buf: User buffer into which to copy the next message on the daemon queue | |
227 | * @count: Amount of space available in @buf | |
228 | * @ppos: Offset in file (ignored) | |
229 | * | |
230 | * Pulls the most recent message from the daemon queue, formats it for | |
231 | * being sent via a miscdevfs handle, and copies it into @buf | |
232 | * | |
233 | * Returns the number of bytes copied into the user buffer | |
234 | */ | |
235 | static int | |
236 | ecryptfs_miscdev_read(struct file *file, char __user *buf, size_t count, | |
237 | loff_t *ppos) | |
238 | { | |
239 | struct ecryptfs_daemon *daemon; | |
240 | struct ecryptfs_msg_ctx *msg_ctx; | |
241 | size_t packet_length_size; | |
242 | u32 counter_nbo; | |
243 | char packet_length[3]; | |
244 | size_t i; | |
245 | size_t total_length; | |
246 | int rc; | |
247 | ||
248 | mutex_lock(&ecryptfs_daemon_hash_mux); | |
249 | /* TODO: Just use file->private_data? */ | |
250 | rc = ecryptfs_find_daemon_by_euid(&daemon, current->euid); | |
251 | BUG_ON(rc || !daemon); | |
252 | mutex_lock(&daemon->mux); | |
253 | if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) { | |
254 | rc = 0; | |
255 | printk(KERN_WARNING "%s: Attempt to read from zombified " | |
256 | "daemon\n", __func__); | |
257 | goto out_unlock_daemon; | |
258 | } | |
259 | if (daemon->flags & ECRYPTFS_DAEMON_IN_READ) { | |
260 | rc = 0; | |
261 | goto out_unlock_daemon; | |
262 | } | |
263 | /* This daemon will not go away so long as this flag is set */ | |
264 | daemon->flags |= ECRYPTFS_DAEMON_IN_READ; | |
265 | mutex_unlock(&ecryptfs_daemon_hash_mux); | |
266 | check_list: | |
267 | if (list_empty(&daemon->msg_ctx_out_queue)) { | |
268 | mutex_unlock(&daemon->mux); | |
269 | rc = wait_event_interruptible( | |
270 | daemon->wait, !list_empty(&daemon->msg_ctx_out_queue)); | |
271 | mutex_lock(&daemon->mux); | |
272 | if (rc < 0) { | |
273 | rc = 0; | |
274 | goto out_unlock_daemon; | |
275 | } | |
276 | } | |
277 | if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) { | |
278 | rc = 0; | |
279 | goto out_unlock_daemon; | |
280 | } | |
281 | if (list_empty(&daemon->msg_ctx_out_queue)) { | |
282 | /* Something else jumped in since the | |
283 | * wait_event_interruptable() and removed the | |
284 | * message from the queue; try again */ | |
285 | goto check_list; | |
286 | } | |
287 | BUG_ON(current->euid != daemon->euid); | |
288 | BUG_ON(current->pid != daemon->pid); | |
289 | msg_ctx = list_first_entry(&daemon->msg_ctx_out_queue, | |
290 | struct ecryptfs_msg_ctx, daemon_out_list); | |
291 | BUG_ON(!msg_ctx); | |
292 | mutex_lock(&msg_ctx->mux); | |
293 | if (msg_ctx->msg) { | |
294 | rc = ecryptfs_write_packet_length(packet_length, | |
295 | msg_ctx->msg_size, | |
296 | &packet_length_size); | |
297 | if (rc) { | |
298 | rc = 0; | |
299 | printk(KERN_WARNING "%s: Error writing packet length; " | |
300 | "rc = [%d]\n", __func__, rc); | |
301 | goto out_unlock_msg_ctx; | |
302 | } | |
303 | } else { | |
304 | packet_length_size = 0; | |
305 | msg_ctx->msg_size = 0; | |
306 | } | |
307 | /* miscdevfs packet format: | |
308 | * Octet 0: Type | |
309 | * Octets 1-4: network byte order msg_ctx->counter | |
310 | * Octets 5-N0: Size of struct ecryptfs_message to follow | |
311 | * Octets N0-N1: struct ecryptfs_message (including data) | |
312 | * | |
313 | * Octets 5-N1 not written if the packet type does not | |
314 | * include a message */ | |
315 | total_length = (1 + 4 + packet_length_size + msg_ctx->msg_size); | |
316 | if (count < total_length) { | |
317 | rc = 0; | |
318 | printk(KERN_WARNING "%s: Only given user buffer of " | |
319 | "size [%Zd], but we need [%Zd] to read the " | |
320 | "pending message\n", __func__, count, total_length); | |
321 | goto out_unlock_msg_ctx; | |
322 | } | |
323 | i = 0; | |
324 | buf[i++] = msg_ctx->type; | |
325 | counter_nbo = cpu_to_be32(msg_ctx->counter); | |
326 | memcpy(&buf[i], (char *)&counter_nbo, 4); | |
327 | i += 4; | |
328 | if (msg_ctx->msg) { | |
329 | memcpy(&buf[i], packet_length, packet_length_size); | |
330 | i += packet_length_size; | |
331 | rc = copy_to_user(&buf[i], msg_ctx->msg, msg_ctx->msg_size); | |
332 | if (rc) { | |
333 | printk(KERN_ERR "%s: copy_to_user returned error " | |
334 | "[%d]\n", __func__, rc); | |
335 | goto out_unlock_msg_ctx; | |
336 | } | |
337 | i += msg_ctx->msg_size; | |
338 | } | |
339 | rc = i; | |
340 | list_del(&msg_ctx->daemon_out_list); | |
341 | kfree(msg_ctx->msg); | |
342 | msg_ctx->msg = NULL; | |
343 | /* We do not expect a reply from the userspace daemon for any | |
344 | * message type other than ECRYPTFS_MSG_REQUEST */ | |
345 | if (msg_ctx->type != ECRYPTFS_MSG_REQUEST) | |
346 | ecryptfs_msg_ctx_alloc_to_free(msg_ctx); | |
347 | out_unlock_msg_ctx: | |
348 | mutex_unlock(&msg_ctx->mux); | |
349 | out_unlock_daemon: | |
350 | daemon->flags &= ~ECRYPTFS_DAEMON_IN_READ; | |
351 | mutex_unlock(&daemon->mux); | |
352 | return rc; | |
353 | } | |
354 | ||
355 | /** | |
356 | * ecryptfs_miscdev_helo | |
357 | * @euid: effective user id of miscdevess sending helo packet | |
358 | * @pid: miscdevess id of miscdevess sending helo packet | |
359 | * | |
360 | * Returns zero on success; non-zero otherwise | |
361 | */ | |
362 | static int ecryptfs_miscdev_helo(uid_t uid, pid_t pid) | |
363 | { | |
364 | int rc; | |
365 | ||
366 | rc = ecryptfs_process_helo(ECRYPTFS_TRANSPORT_MISCDEV, uid, pid); | |
367 | if (rc) | |
368 | printk(KERN_WARNING "Error processing HELO; rc = [%d]\n", rc); | |
369 | return rc; | |
370 | } | |
371 | ||
372 | /** | |
373 | * ecryptfs_miscdev_quit | |
374 | * @euid: effective user id of miscdevess sending quit packet | |
375 | * @pid: miscdevess id of miscdevess sending quit packet | |
376 | * | |
377 | * Returns zero on success; non-zero otherwise | |
378 | */ | |
379 | static int ecryptfs_miscdev_quit(uid_t euid, pid_t pid) | |
380 | { | |
381 | int rc; | |
382 | ||
383 | rc = ecryptfs_process_quit(euid, pid); | |
384 | if (rc) | |
385 | printk(KERN_WARNING | |
386 | "Error processing QUIT message; rc = [%d]\n", rc); | |
387 | return rc; | |
388 | } | |
389 | ||
390 | /** | |
391 | * ecryptfs_miscdev_response - miscdevess response to message previously sent to daemon | |
392 | * @data: Bytes comprising struct ecryptfs_message | |
393 | * @data_size: sizeof(struct ecryptfs_message) + data len | |
394 | * @euid: Effective user id of miscdevess sending the miscdev response | |
395 | * @pid: Miscdevess id of miscdevess sending the miscdev response | |
396 | * @seq: Sequence number for miscdev response packet | |
397 | * | |
398 | * Returns zero on success; non-zero otherwise | |
399 | */ | |
400 | static int ecryptfs_miscdev_response(char *data, size_t data_size, | |
401 | uid_t euid, pid_t pid, u32 seq) | |
402 | { | |
403 | struct ecryptfs_message *msg = (struct ecryptfs_message *)data; | |
404 | int rc; | |
405 | ||
406 | if ((sizeof(*msg) + msg->data_len) != data_size) { | |
407 | printk(KERN_WARNING "%s: (sizeof(*msg) + msg->data_len) = " | |
408 | "[%Zd]; data_size = [%Zd]. Invalid packet.\n", __func__, | |
409 | (sizeof(*msg) + msg->data_len), data_size); | |
410 | rc = -EINVAL; | |
411 | goto out; | |
412 | } | |
413 | rc = ecryptfs_process_response(msg, euid, pid, seq); | |
414 | if (rc) | |
415 | printk(KERN_ERR | |
416 | "Error processing response message; rc = [%d]\n", rc); | |
417 | out: | |
418 | return rc; | |
419 | } | |
420 | ||
421 | /** | |
422 | * ecryptfs_miscdev_write - handle write to daemon miscdev handle | |
423 | * @file: File for misc dev handle (ignored) | |
424 | * @buf: Buffer containing user data | |
425 | * @count: Amount of data in @buf | |
426 | * @ppos: Pointer to offset in file (ignored) | |
427 | * | |
428 | * miscdevfs packet format: | |
429 | * Octet 0: Type | |
430 | * Octets 1-4: network byte order msg_ctx->counter (0's for non-response) | |
431 | * Octets 5-N0: Size of struct ecryptfs_message to follow | |
432 | * Octets N0-N1: struct ecryptfs_message (including data) | |
433 | * | |
434 | * Returns the number of bytes read from @buf | |
435 | */ | |
436 | static ssize_t | |
437 | ecryptfs_miscdev_write(struct file *file, const char __user *buf, | |
438 | size_t count, loff_t *ppos) | |
439 | { | |
440 | u32 counter_nbo, seq; | |
441 | size_t packet_size, packet_size_length, i; | |
442 | ssize_t sz = 0; | |
443 | char *data; | |
444 | int rc; | |
445 | ||
446 | if (count == 0) | |
447 | goto out; | |
448 | data = kmalloc(count, GFP_KERNEL); | |
449 | if (!data) { | |
450 | printk(KERN_ERR "%s: Out of memory whilst attempting to " | |
451 | "kmalloc([%Zd], GFP_KERNEL)\n", __func__, count); | |
452 | goto out; | |
453 | } | |
454 | rc = copy_from_user(data, buf, count); | |
455 | if (rc) { | |
456 | printk(KERN_ERR "%s: copy_from_user returned error [%d]\n", | |
457 | __func__, rc); | |
458 | goto out_free; | |
459 | } | |
460 | sz = count; | |
461 | i = 0; | |
462 | switch (data[i++]) { | |
463 | case ECRYPTFS_MSG_RESPONSE: | |
464 | if (count < (1 + 4 + 1 + sizeof(struct ecryptfs_message))) { | |
465 | printk(KERN_WARNING "%s: Minimum acceptable packet " | |
466 | "size is [%Zd], but amount of data written is " | |
467 | "only [%Zd]. Discarding response packet.\n", | |
468 | __func__, | |
469 | (1 + 4 + 1 + sizeof(struct ecryptfs_message)), | |
470 | count); | |
471 | goto out_free; | |
472 | } | |
473 | memcpy((char *)&counter_nbo, &data[i], 4); | |
474 | seq = be32_to_cpu(counter_nbo); | |
475 | i += 4; | |
476 | rc = ecryptfs_parse_packet_length(&data[i], &packet_size, | |
477 | &packet_size_length); | |
478 | if (rc) { | |
479 | printk(KERN_WARNING "%s: Error parsing packet length; " | |
480 | "rc = [%d]\n", __func__, rc); | |
481 | goto out_free; | |
482 | } | |
483 | i += packet_size_length; | |
484 | if ((1 + 4 + packet_size_length + packet_size) != count) { | |
485 | printk(KERN_WARNING "%s: (1 + packet_size_length([%Zd])" | |
486 | " + packet_size([%Zd]))([%Zd]) != " | |
487 | "count([%Zd]). Invalid packet format.\n", | |
488 | __func__, packet_size_length, packet_size, | |
489 | (1 + packet_size_length + packet_size), count); | |
490 | goto out_free; | |
491 | } | |
492 | rc = ecryptfs_miscdev_response(&data[i], packet_size, | |
493 | current->euid, | |
494 | current->pid, seq); | |
495 | if (rc) | |
496 | printk(KERN_WARNING "%s: Failed to deliver miscdev " | |
497 | "response to requesting operation; rc = [%d]\n", | |
498 | __func__, rc); | |
499 | break; | |
500 | case ECRYPTFS_MSG_HELO: | |
501 | rc = ecryptfs_miscdev_helo(current->euid, current->pid); | |
502 | if (rc) { | |
503 | printk(KERN_ERR "%s: Error attempting to process " | |
504 | "helo from pid [%d]; rc = [%d]\n", __func__, | |
505 | current->pid, rc); | |
506 | goto out_free; | |
507 | } | |
508 | break; | |
509 | case ECRYPTFS_MSG_QUIT: | |
510 | rc = ecryptfs_miscdev_quit(current->euid, current->pid); | |
511 | if (rc) { | |
512 | printk(KERN_ERR "%s: Error attempting to process " | |
513 | "quit from pid [%d]; rc = [%d]\n", __func__, | |
514 | current->pid, rc); | |
515 | goto out_free; | |
516 | } | |
517 | break; | |
518 | default: | |
519 | ecryptfs_printk(KERN_WARNING, "Dropping miscdev " | |
520 | "message of unrecognized type [%d]\n", | |
521 | data[0]); | |
522 | break; | |
523 | } | |
524 | out_free: | |
525 | kfree(data); | |
526 | out: | |
527 | return sz; | |
528 | } | |
529 | ||
530 | ||
531 | static const struct file_operations ecryptfs_miscdev_fops = { | |
532 | .open = ecryptfs_miscdev_open, | |
533 | .poll = ecryptfs_miscdev_poll, | |
534 | .read = ecryptfs_miscdev_read, | |
535 | .write = ecryptfs_miscdev_write, | |
536 | .release = ecryptfs_miscdev_release, | |
537 | }; | |
538 | ||
539 | static struct miscdevice ecryptfs_miscdev = { | |
540 | .minor = MISC_DYNAMIC_MINOR, | |
541 | .name = "ecryptfs", | |
542 | .fops = &ecryptfs_miscdev_fops | |
543 | }; | |
544 | ||
545 | /** | |
546 | * ecryptfs_init_ecryptfs_miscdev | |
547 | * | |
548 | * Messages sent to the userspace daemon from the kernel are placed on | |
549 | * a queue associated with the daemon. The next read against the | |
550 | * miscdev handle by that daemon will return the oldest message placed | |
551 | * on the message queue for the daemon. | |
552 | * | |
553 | * Returns zero on success; non-zero otherwise | |
554 | */ | |
555 | int ecryptfs_init_ecryptfs_miscdev(void) | |
556 | { | |
557 | int rc; | |
558 | ||
559 | atomic_set(&ecryptfs_num_miscdev_opens, 0); | |
560 | mutex_lock(&ecryptfs_daemon_hash_mux); | |
561 | rc = misc_register(&ecryptfs_miscdev); | |
562 | if (rc) | |
563 | printk(KERN_ERR "%s: Failed to register miscellaneous device " | |
564 | "for communications with userspace daemons; rc = [%d]\n", | |
565 | __func__, rc); | |
566 | mutex_unlock(&ecryptfs_daemon_hash_mux); | |
567 | return rc; | |
568 | } | |
569 | ||
570 | /** | |
571 | * ecryptfs_destroy_ecryptfs_miscdev | |
572 | * | |
573 | * All of the daemons must be exorcised prior to calling this | |
574 | * function. | |
575 | */ | |
576 | void ecryptfs_destroy_ecryptfs_miscdev(void) | |
577 | { | |
578 | BUG_ON(atomic_read(&ecryptfs_num_miscdev_opens) != 0); | |
579 | misc_deregister(&ecryptfs_miscdev); | |
580 | } |