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Commit | Line | Data |
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8bf2debd MH |
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; | |
4eea0353 | 45 | uid_t euid = current_euid(); |
8bf2debd MH |
46 | int rc; |
47 | ||
48 | mutex_lock(&ecryptfs_daemon_hash_mux); | |
49 | /* TODO: Just use file->private_data? */ | |
18b6e041 | 50 | rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns()); |
8bf2debd MH |
51 | BUG_ON(rc || !daemon); |
52 | mutex_lock(&daemon->mux); | |
53 | mutex_unlock(&ecryptfs_daemon_hash_mux); | |
54 | if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) { | |
55 | printk(KERN_WARNING "%s: Attempt to poll on zombified " | |
56 | "daemon\n", __func__); | |
57 | goto out_unlock_daemon; | |
58 | } | |
59 | if (daemon->flags & ECRYPTFS_DAEMON_IN_READ) | |
60 | goto out_unlock_daemon; | |
61 | if (daemon->flags & ECRYPTFS_DAEMON_IN_POLL) | |
62 | goto out_unlock_daemon; | |
63 | daemon->flags |= ECRYPTFS_DAEMON_IN_POLL; | |
64 | mutex_unlock(&daemon->mux); | |
65 | poll_wait(file, &daemon->wait, pt); | |
66 | mutex_lock(&daemon->mux); | |
67 | if (!list_empty(&daemon->msg_ctx_out_queue)) | |
68 | mask |= POLLIN | POLLRDNORM; | |
69 | out_unlock_daemon: | |
70 | daemon->flags &= ~ECRYPTFS_DAEMON_IN_POLL; | |
71 | mutex_unlock(&daemon->mux); | |
72 | return mask; | |
73 | } | |
74 | ||
75 | /** | |
76 | * ecryptfs_miscdev_open | |
77 | * @inode: inode of miscdev handle (ignored) | |
78 | * @file: file for miscdev handle (ignored) | |
79 | * | |
80 | * Returns zero on success; non-zero otherwise | |
81 | */ | |
82 | static int | |
83 | ecryptfs_miscdev_open(struct inode *inode, struct file *file) | |
84 | { | |
85 | struct ecryptfs_daemon *daemon = NULL; | |
4eea0353 | 86 | uid_t euid = current_euid(); |
8bf2debd MH |
87 | int rc; |
88 | ||
89 | mutex_lock(&ecryptfs_daemon_hash_mux); | |
90 | rc = try_module_get(THIS_MODULE); | |
91 | if (rc == 0) { | |
92 | rc = -EIO; | |
93 | printk(KERN_ERR "%s: Error attempting to increment module use " | |
94 | "count; rc = [%d]\n", __func__, rc); | |
95 | goto out_unlock_daemon_list; | |
96 | } | |
18b6e041 | 97 | rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns()); |
8bf2debd | 98 | if (rc || !daemon) { |
18b6e041 | 99 | rc = ecryptfs_spawn_daemon(&daemon, euid, current_user_ns(), |
6a3fd92e | 100 | task_pid(current)); |
8bf2debd MH |
101 | if (rc) { |
102 | printk(KERN_ERR "%s: Error attempting to spawn daemon; " | |
103 | "rc = [%d]\n", __func__, rc); | |
104 | goto out_module_put_unlock_daemon_list; | |
105 | } | |
106 | } | |
107 | mutex_lock(&daemon->mux); | |
6a3fd92e | 108 | if (daemon->pid != task_pid(current)) { |
8bf2debd | 109 | rc = -EINVAL; |
6a3fd92e MH |
110 | printk(KERN_ERR "%s: pid [0x%p] has registered with euid [%d], " |
111 | "but pid [0x%p] has attempted to open the handle " | |
8bf2debd | 112 | "instead\n", __func__, daemon->pid, daemon->euid, |
6a3fd92e | 113 | task_pid(current)); |
8bf2debd MH |
114 | goto out_unlock_daemon; |
115 | } | |
116 | if (daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN) { | |
117 | rc = -EBUSY; | |
118 | printk(KERN_ERR "%s: Miscellaneous device handle may only be " | |
6a3fd92e | 119 | "opened once per daemon; pid [0x%p] already has this " |
8bf2debd MH |
120 | "handle open\n", __func__, daemon->pid); |
121 | goto out_unlock_daemon; | |
122 | } | |
123 | daemon->flags |= ECRYPTFS_DAEMON_MISCDEV_OPEN; | |
124 | atomic_inc(&ecryptfs_num_miscdev_opens); | |
125 | out_unlock_daemon: | |
126 | mutex_unlock(&daemon->mux); | |
127 | out_module_put_unlock_daemon_list: | |
128 | if (rc) | |
129 | module_put(THIS_MODULE); | |
130 | out_unlock_daemon_list: | |
131 | mutex_unlock(&ecryptfs_daemon_hash_mux); | |
132 | return rc; | |
133 | } | |
134 | ||
135 | /** | |
136 | * ecryptfs_miscdev_release | |
137 | * @inode: inode of fs/ecryptfs/euid handle (ignored) | |
138 | * @file: file for fs/ecryptfs/euid handle (ignored) | |
139 | * | |
140 | * This keeps the daemon registered until the daemon sends another | |
141 | * ioctl to fs/ecryptfs/ctl or until the kernel module unregisters. | |
142 | * | |
143 | * Returns zero on success; non-zero otherwise | |
144 | */ | |
145 | static int | |
146 | ecryptfs_miscdev_release(struct inode *inode, struct file *file) | |
147 | { | |
148 | struct ecryptfs_daemon *daemon = NULL; | |
4eea0353 | 149 | uid_t euid = current_euid(); |
8bf2debd MH |
150 | int rc; |
151 | ||
152 | mutex_lock(&ecryptfs_daemon_hash_mux); | |
18b6e041 | 153 | rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns()); |
8bf2debd MH |
154 | BUG_ON(rc || !daemon); |
155 | mutex_lock(&daemon->mux); | |
6a3fd92e | 156 | BUG_ON(daemon->pid != task_pid(current)); |
8bf2debd MH |
157 | BUG_ON(!(daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN)); |
158 | daemon->flags &= ~ECRYPTFS_DAEMON_MISCDEV_OPEN; | |
159 | atomic_dec(&ecryptfs_num_miscdev_opens); | |
160 | mutex_unlock(&daemon->mux); | |
161 | rc = ecryptfs_exorcise_daemon(daemon); | |
162 | if (rc) { | |
163 | printk(KERN_CRIT "%s: Fatal error whilst attempting to " | |
164 | "shut down daemon; rc = [%d]. Please report this " | |
165 | "bug.\n", __func__, rc); | |
166 | BUG(); | |
167 | } | |
168 | module_put(THIS_MODULE); | |
169 | mutex_unlock(&ecryptfs_daemon_hash_mux); | |
170 | return rc; | |
171 | } | |
172 | ||
173 | /** | |
174 | * ecryptfs_send_miscdev | |
175 | * @data: Data to send to daemon; may be NULL | |
176 | * @data_size: Amount of data to send to daemon | |
177 | * @msg_ctx: Message context, which is used to handle the reply. If | |
178 | * this is NULL, then we do not expect a reply. | |
179 | * @msg_type: Type of message | |
180 | * @msg_flags: Flags for message | |
181 | * @daemon: eCryptfs daemon object | |
182 | * | |
183 | * Add msg_ctx to queue and then, if it exists, notify the blocked | |
184 | * miscdevess about the data being available. Must be called with | |
185 | * ecryptfs_daemon_hash_mux held. | |
186 | * | |
187 | * Returns zero on success; non-zero otherwise | |
188 | */ | |
189 | int ecryptfs_send_miscdev(char *data, size_t data_size, | |
190 | struct ecryptfs_msg_ctx *msg_ctx, u8 msg_type, | |
191 | u16 msg_flags, struct ecryptfs_daemon *daemon) | |
192 | { | |
193 | int rc = 0; | |
194 | ||
195 | mutex_lock(&msg_ctx->mux); | |
57ea34d1 TH |
196 | msg_ctx->msg = kmalloc((sizeof(*msg_ctx->msg) + data_size), |
197 | GFP_KERNEL); | |
198 | if (!msg_ctx->msg) { | |
199 | rc = -ENOMEM; | |
200 | printk(KERN_ERR "%s: Out of memory whilst attempting " | |
201 | "to kmalloc(%zd, GFP_KERNEL)\n", __func__, | |
202 | (sizeof(*msg_ctx->msg) + data_size)); | |
203 | goto out_unlock; | |
204 | } | |
8bf2debd MH |
205 | msg_ctx->msg->index = msg_ctx->index; |
206 | msg_ctx->msg->data_len = data_size; | |
207 | msg_ctx->type = msg_type; | |
57ea34d1 TH |
208 | memcpy(msg_ctx->msg->data, data, data_size); |
209 | msg_ctx->msg_size = (sizeof(*msg_ctx->msg) + data_size); | |
8bf2debd MH |
210 | mutex_lock(&daemon->mux); |
211 | list_add_tail(&msg_ctx->daemon_out_list, &daemon->msg_ctx_out_queue); | |
212 | daemon->num_queued_msg_ctx++; | |
213 | wake_up_interruptible(&daemon->wait); | |
214 | mutex_unlock(&daemon->mux); | |
215 | out_unlock: | |
216 | mutex_unlock(&msg_ctx->mux); | |
217 | return rc; | |
218 | } | |
219 | ||
220 | /** | |
221 | * ecryptfs_miscdev_read - format and send message from queue | |
222 | * @file: fs/ecryptfs/euid miscdevfs handle (ignored) | |
223 | * @buf: User buffer into which to copy the next message on the daemon queue | |
224 | * @count: Amount of space available in @buf | |
225 | * @ppos: Offset in file (ignored) | |
226 | * | |
227 | * Pulls the most recent message from the daemon queue, formats it for | |
228 | * being sent via a miscdevfs handle, and copies it into @buf | |
229 | * | |
230 | * Returns the number of bytes copied into the user buffer | |
231 | */ | |
f66e883e | 232 | static ssize_t |
8bf2debd MH |
233 | ecryptfs_miscdev_read(struct file *file, char __user *buf, size_t count, |
234 | loff_t *ppos) | |
235 | { | |
236 | struct ecryptfs_daemon *daemon; | |
237 | struct ecryptfs_msg_ctx *msg_ctx; | |
238 | size_t packet_length_size; | |
8bf2debd MH |
239 | char packet_length[3]; |
240 | size_t i; | |
241 | size_t total_length; | |
4eea0353 | 242 | uid_t euid = current_euid(); |
8bf2debd MH |
243 | int rc; |
244 | ||
245 | mutex_lock(&ecryptfs_daemon_hash_mux); | |
246 | /* TODO: Just use file->private_data? */ | |
18b6e041 | 247 | rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns()); |
8bf2debd MH |
248 | BUG_ON(rc || !daemon); |
249 | mutex_lock(&daemon->mux); | |
250 | if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) { | |
251 | rc = 0; | |
43f14d85 | 252 | mutex_unlock(&ecryptfs_daemon_hash_mux); |
8bf2debd MH |
253 | printk(KERN_WARNING "%s: Attempt to read from zombified " |
254 | "daemon\n", __func__); | |
255 | goto out_unlock_daemon; | |
256 | } | |
257 | if (daemon->flags & ECRYPTFS_DAEMON_IN_READ) { | |
258 | rc = 0; | |
43f14d85 | 259 | mutex_unlock(&ecryptfs_daemon_hash_mux); |
8bf2debd MH |
260 | goto out_unlock_daemon; |
261 | } | |
262 | /* This daemon will not go away so long as this flag is set */ | |
263 | daemon->flags |= ECRYPTFS_DAEMON_IN_READ; | |
264 | mutex_unlock(&ecryptfs_daemon_hash_mux); | |
265 | check_list: | |
266 | if (list_empty(&daemon->msg_ctx_out_queue)) { | |
267 | mutex_unlock(&daemon->mux); | |
268 | rc = wait_event_interruptible( | |
269 | daemon->wait, !list_empty(&daemon->msg_ctx_out_queue)); | |
270 | mutex_lock(&daemon->mux); | |
271 | if (rc < 0) { | |
272 | rc = 0; | |
273 | goto out_unlock_daemon; | |
274 | } | |
275 | } | |
276 | if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) { | |
277 | rc = 0; | |
278 | goto out_unlock_daemon; | |
279 | } | |
280 | if (list_empty(&daemon->msg_ctx_out_queue)) { | |
281 | /* Something else jumped in since the | |
282 | * wait_event_interruptable() and removed the | |
283 | * message from the queue; try again */ | |
284 | goto check_list; | |
285 | } | |
4eea0353 | 286 | BUG_ON(euid != daemon->euid); |
18b6e041 | 287 | BUG_ON(current_user_ns() != daemon->user_ns); |
6a3fd92e | 288 | BUG_ON(task_pid(current) != daemon->pid); |
8bf2debd MH |
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 " | |
df261c52 | 319 | "size [%zd], but we need [%zd] to read the " |
8bf2debd MH |
320 | "pending message\n", __func__, count, total_length); |
321 | goto out_unlock_msg_ctx; | |
322 | } | |
79bc12a0 AV |
323 | rc = -EFAULT; |
324 | if (put_user(msg_ctx->type, buf)) | |
325 | goto out_unlock_msg_ctx; | |
326 | if (put_user(cpu_to_be32(msg_ctx->counter), (__be32 __user *)(buf + 1))) | |
327 | goto out_unlock_msg_ctx; | |
328 | i = 5; | |
8bf2debd | 329 | if (msg_ctx->msg) { |
79bc12a0 AV |
330 | if (copy_to_user(&buf[i], packet_length, packet_length_size)) |
331 | goto out_unlock_msg_ctx; | |
8bf2debd | 332 | i += packet_length_size; |
79bc12a0 | 333 | if (copy_to_user(&buf[i], msg_ctx->msg, msg_ctx->msg_size)) |
8bf2debd | 334 | goto out_unlock_msg_ctx; |
8bf2debd MH |
335 | i += msg_ctx->msg_size; |
336 | } | |
337 | rc = i; | |
338 | list_del(&msg_ctx->daemon_out_list); | |
339 | kfree(msg_ctx->msg); | |
340 | msg_ctx->msg = NULL; | |
341 | /* We do not expect a reply from the userspace daemon for any | |
342 | * message type other than ECRYPTFS_MSG_REQUEST */ | |
343 | if (msg_ctx->type != ECRYPTFS_MSG_REQUEST) | |
344 | ecryptfs_msg_ctx_alloc_to_free(msg_ctx); | |
345 | out_unlock_msg_ctx: | |
346 | mutex_unlock(&msg_ctx->mux); | |
347 | out_unlock_daemon: | |
348 | daemon->flags &= ~ECRYPTFS_DAEMON_IN_READ; | |
349 | mutex_unlock(&daemon->mux); | |
350 | return rc; | |
351 | } | |
352 | ||
8bf2debd MH |
353 | /** |
354 | * ecryptfs_miscdev_response - miscdevess response to message previously sent to daemon | |
355 | * @data: Bytes comprising struct ecryptfs_message | |
356 | * @data_size: sizeof(struct ecryptfs_message) + data len | |
357 | * @euid: Effective user id of miscdevess sending the miscdev response | |
6a3fd92e | 358 | * @user_ns: The namespace in which @euid applies |
8bf2debd MH |
359 | * @pid: Miscdevess id of miscdevess sending the miscdev response |
360 | * @seq: Sequence number for miscdev response packet | |
361 | * | |
362 | * Returns zero on success; non-zero otherwise | |
363 | */ | |
364 | static int ecryptfs_miscdev_response(char *data, size_t data_size, | |
6a3fd92e MH |
365 | uid_t euid, struct user_namespace *user_ns, |
366 | struct pid *pid, u32 seq) | |
8bf2debd MH |
367 | { |
368 | struct ecryptfs_message *msg = (struct ecryptfs_message *)data; | |
369 | int rc; | |
370 | ||
371 | if ((sizeof(*msg) + msg->data_len) != data_size) { | |
372 | printk(KERN_WARNING "%s: (sizeof(*msg) + msg->data_len) = " | |
df261c52 | 373 | "[%zd]; data_size = [%zd]. Invalid packet.\n", __func__, |
8bf2debd MH |
374 | (sizeof(*msg) + msg->data_len), data_size); |
375 | rc = -EINVAL; | |
376 | goto out; | |
377 | } | |
6a3fd92e | 378 | rc = ecryptfs_process_response(msg, euid, user_ns, pid, seq); |
8bf2debd MH |
379 | if (rc) |
380 | printk(KERN_ERR | |
381 | "Error processing response message; rc = [%d]\n", rc); | |
382 | out: | |
383 | return rc; | |
384 | } | |
385 | ||
386 | /** | |
387 | * ecryptfs_miscdev_write - handle write to daemon miscdev handle | |
388 | * @file: File for misc dev handle (ignored) | |
389 | * @buf: Buffer containing user data | |
390 | * @count: Amount of data in @buf | |
391 | * @ppos: Pointer to offset in file (ignored) | |
392 | * | |
393 | * miscdevfs packet format: | |
394 | * Octet 0: Type | |
395 | * Octets 1-4: network byte order msg_ctx->counter (0's for non-response) | |
396 | * Octets 5-N0: Size of struct ecryptfs_message to follow | |
397 | * Octets N0-N1: struct ecryptfs_message (including data) | |
398 | * | |
399 | * Returns the number of bytes read from @buf | |
400 | */ | |
401 | static ssize_t | |
402 | ecryptfs_miscdev_write(struct file *file, const char __user *buf, | |
403 | size_t count, loff_t *ppos) | |
404 | { | |
79bc12a0 AV |
405 | __be32 counter_nbo; |
406 | u32 seq; | |
8bf2debd MH |
407 | size_t packet_size, packet_size_length, i; |
408 | ssize_t sz = 0; | |
409 | char *data; | |
4eea0353 | 410 | uid_t euid = current_euid(); |
8bf2debd MH |
411 | int rc; |
412 | ||
413 | if (count == 0) | |
414 | goto out; | |
fd56d242 LZ |
415 | |
416 | data = memdup_user(buf, count); | |
417 | if (IS_ERR(data)) { | |
418 | printk(KERN_ERR "%s: memdup_user returned error [%ld]\n", | |
419 | __func__, PTR_ERR(data)); | |
8bf2debd MH |
420 | goto out; |
421 | } | |
8bf2debd MH |
422 | sz = count; |
423 | i = 0; | |
424 | switch (data[i++]) { | |
425 | case ECRYPTFS_MSG_RESPONSE: | |
426 | if (count < (1 + 4 + 1 + sizeof(struct ecryptfs_message))) { | |
427 | printk(KERN_WARNING "%s: Minimum acceptable packet " | |
df261c52 MH |
428 | "size is [%zd], but amount of data written is " |
429 | "only [%zd]. Discarding response packet.\n", | |
8bf2debd MH |
430 | __func__, |
431 | (1 + 4 + 1 + sizeof(struct ecryptfs_message)), | |
432 | count); | |
433 | goto out_free; | |
434 | } | |
79bc12a0 | 435 | memcpy(&counter_nbo, &data[i], 4); |
8bf2debd MH |
436 | seq = be32_to_cpu(counter_nbo); |
437 | i += 4; | |
438 | rc = ecryptfs_parse_packet_length(&data[i], &packet_size, | |
439 | &packet_size_length); | |
440 | if (rc) { | |
441 | printk(KERN_WARNING "%s: Error parsing packet length; " | |
442 | "rc = [%d]\n", __func__, rc); | |
443 | goto out_free; | |
444 | } | |
445 | i += packet_size_length; | |
446 | if ((1 + 4 + packet_size_length + packet_size) != count) { | |
df261c52 MH |
447 | printk(KERN_WARNING "%s: (1 + packet_size_length([%zd])" |
448 | " + packet_size([%zd]))([%zd]) != " | |
449 | "count([%zd]). Invalid packet format.\n", | |
8bf2debd MH |
450 | __func__, packet_size_length, packet_size, |
451 | (1 + packet_size_length + packet_size), count); | |
452 | goto out_free; | |
453 | } | |
454 | rc = ecryptfs_miscdev_response(&data[i], packet_size, | |
18b6e041 | 455 | euid, current_user_ns(), |
6a3fd92e | 456 | task_pid(current), seq); |
8bf2debd MH |
457 | if (rc) |
458 | printk(KERN_WARNING "%s: Failed to deliver miscdev " | |
459 | "response to requesting operation; rc = [%d]\n", | |
460 | __func__, rc); | |
461 | break; | |
462 | case ECRYPTFS_MSG_HELO: | |
8bf2debd | 463 | case ECRYPTFS_MSG_QUIT: |
8bf2debd MH |
464 | break; |
465 | default: | |
466 | ecryptfs_printk(KERN_WARNING, "Dropping miscdev " | |
467 | "message of unrecognized type [%d]\n", | |
468 | data[0]); | |
469 | break; | |
470 | } | |
471 | out_free: | |
472 | kfree(data); | |
473 | out: | |
474 | return sz; | |
475 | } | |
476 | ||
477 | ||
478 | static const struct file_operations ecryptfs_miscdev_fops = { | |
479 | .open = ecryptfs_miscdev_open, | |
480 | .poll = ecryptfs_miscdev_poll, | |
481 | .read = ecryptfs_miscdev_read, | |
482 | .write = ecryptfs_miscdev_write, | |
483 | .release = ecryptfs_miscdev_release, | |
484 | }; | |
485 | ||
486 | static struct miscdevice ecryptfs_miscdev = { | |
487 | .minor = MISC_DYNAMIC_MINOR, | |
488 | .name = "ecryptfs", | |
489 | .fops = &ecryptfs_miscdev_fops | |
490 | }; | |
491 | ||
492 | /** | |
493 | * ecryptfs_init_ecryptfs_miscdev | |
494 | * | |
495 | * Messages sent to the userspace daemon from the kernel are placed on | |
496 | * a queue associated with the daemon. The next read against the | |
497 | * miscdev handle by that daemon will return the oldest message placed | |
498 | * on the message queue for the daemon. | |
499 | * | |
500 | * Returns zero on success; non-zero otherwise | |
501 | */ | |
502 | int ecryptfs_init_ecryptfs_miscdev(void) | |
503 | { | |
504 | int rc; | |
505 | ||
506 | atomic_set(&ecryptfs_num_miscdev_opens, 0); | |
8bf2debd MH |
507 | rc = misc_register(&ecryptfs_miscdev); |
508 | if (rc) | |
509 | printk(KERN_ERR "%s: Failed to register miscellaneous device " | |
510 | "for communications with userspace daemons; rc = [%d]\n", | |
511 | __func__, rc); | |
8bf2debd MH |
512 | return rc; |
513 | } | |
514 | ||
515 | /** | |
516 | * ecryptfs_destroy_ecryptfs_miscdev | |
517 | * | |
518 | * All of the daemons must be exorcised prior to calling this | |
519 | * function. | |
520 | */ | |
521 | void ecryptfs_destroy_ecryptfs_miscdev(void) | |
522 | { | |
523 | BUG_ON(atomic_read(&ecryptfs_num_miscdev_opens) != 0); | |
524 | misc_deregister(&ecryptfs_miscdev); | |
525 | } |