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45051539 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
8bf2debd MH |
2 | /** |
3 | * eCryptfs: Linux filesystem encryption layer | |
4 | * | |
5 | * Copyright (C) 2008 International Business Machines Corp. | |
6 | * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com> | |
8bf2debd MH |
7 | */ |
8 | ||
9 | #include <linux/fs.h> | |
10 | #include <linux/hash.h> | |
11 | #include <linux/random.h> | |
12 | #include <linux/miscdevice.h> | |
13 | #include <linux/poll.h> | |
5a0e3ad6 | 14 | #include <linux/slab.h> |
8bf2debd MH |
15 | #include <linux/wait.h> |
16 | #include <linux/module.h> | |
17 | #include "ecryptfs_kernel.h" | |
18 | ||
19 | static atomic_t ecryptfs_num_miscdev_opens; | |
20 | ||
21 | /** | |
22 | * ecryptfs_miscdev_poll | |
2ecaf55d | 23 | * @file: dev file |
8bf2debd MH |
24 | * @pt: dev poll table (ignored) |
25 | * | |
26 | * Returns the poll mask | |
27 | */ | |
076ccb76 | 28 | static __poll_t |
8bf2debd MH |
29 | ecryptfs_miscdev_poll(struct file *file, poll_table *pt) |
30 | { | |
2ecaf55d | 31 | struct ecryptfs_daemon *daemon = file->private_data; |
076ccb76 | 32 | __poll_t mask = 0; |
8bf2debd | 33 | |
8bf2debd | 34 | mutex_lock(&daemon->mux); |
8bf2debd MH |
35 | if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) { |
36 | printk(KERN_WARNING "%s: Attempt to poll on zombified " | |
37 | "daemon\n", __func__); | |
38 | goto out_unlock_daemon; | |
39 | } | |
40 | if (daemon->flags & ECRYPTFS_DAEMON_IN_READ) | |
41 | goto out_unlock_daemon; | |
42 | if (daemon->flags & ECRYPTFS_DAEMON_IN_POLL) | |
43 | goto out_unlock_daemon; | |
44 | daemon->flags |= ECRYPTFS_DAEMON_IN_POLL; | |
45 | mutex_unlock(&daemon->mux); | |
46 | poll_wait(file, &daemon->wait, pt); | |
47 | mutex_lock(&daemon->mux); | |
48 | if (!list_empty(&daemon->msg_ctx_out_queue)) | |
a9a08845 | 49 | mask |= EPOLLIN | EPOLLRDNORM; |
8bf2debd MH |
50 | out_unlock_daemon: |
51 | daemon->flags &= ~ECRYPTFS_DAEMON_IN_POLL; | |
52 | mutex_unlock(&daemon->mux); | |
53 | return mask; | |
54 | } | |
55 | ||
56 | /** | |
57 | * ecryptfs_miscdev_open | |
58 | * @inode: inode of miscdev handle (ignored) | |
2ecaf55d | 59 | * @file: file for miscdev handle |
8bf2debd MH |
60 | * |
61 | * Returns zero on success; non-zero otherwise | |
62 | */ | |
63 | static int | |
64 | ecryptfs_miscdev_open(struct inode *inode, struct file *file) | |
65 | { | |
66 | struct ecryptfs_daemon *daemon = NULL; | |
67 | int rc; | |
68 | ||
69 | mutex_lock(&ecryptfs_daemon_hash_mux); | |
2ecaf55d TH |
70 | rc = ecryptfs_find_daemon_by_euid(&daemon); |
71 | if (!rc) { | |
8bf2debd | 72 | rc = -EINVAL; |
2ecaf55d TH |
73 | goto out_unlock_daemon_list; |
74 | } | |
75 | rc = ecryptfs_spawn_daemon(&daemon, file); | |
76 | if (rc) { | |
77 | printk(KERN_ERR "%s: Error attempting to spawn daemon; " | |
78 | "rc = [%d]\n", __func__, rc); | |
52f21999 | 79 | goto out_unlock_daemon_list; |
8bf2debd | 80 | } |
2ecaf55d | 81 | mutex_lock(&daemon->mux); |
8bf2debd MH |
82 | if (daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN) { |
83 | rc = -EBUSY; | |
8bf2debd MH |
84 | goto out_unlock_daemon; |
85 | } | |
86 | daemon->flags |= ECRYPTFS_DAEMON_MISCDEV_OPEN; | |
8dc67805 | 87 | file->private_data = daemon; |
8bf2debd MH |
88 | atomic_inc(&ecryptfs_num_miscdev_opens); |
89 | out_unlock_daemon: | |
90 | mutex_unlock(&daemon->mux); | |
8bf2debd MH |
91 | out_unlock_daemon_list: |
92 | mutex_unlock(&ecryptfs_daemon_hash_mux); | |
93 | return rc; | |
94 | } | |
95 | ||
96 | /** | |
97 | * ecryptfs_miscdev_release | |
98 | * @inode: inode of fs/ecryptfs/euid handle (ignored) | |
2ecaf55d | 99 | * @file: file for fs/ecryptfs/euid handle |
8bf2debd MH |
100 | * |
101 | * This keeps the daemon registered until the daemon sends another | |
102 | * ioctl to fs/ecryptfs/ctl or until the kernel module unregisters. | |
103 | * | |
104 | * Returns zero on success; non-zero otherwise | |
105 | */ | |
106 | static int | |
107 | ecryptfs_miscdev_release(struct inode *inode, struct file *file) | |
108 | { | |
2ecaf55d | 109 | struct ecryptfs_daemon *daemon = file->private_data; |
8bf2debd MH |
110 | int rc; |
111 | ||
8bf2debd | 112 | mutex_lock(&daemon->mux); |
8bf2debd MH |
113 | BUG_ON(!(daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN)); |
114 | daemon->flags &= ~ECRYPTFS_DAEMON_MISCDEV_OPEN; | |
115 | atomic_dec(&ecryptfs_num_miscdev_opens); | |
116 | mutex_unlock(&daemon->mux); | |
2ecaf55d TH |
117 | |
118 | mutex_lock(&ecryptfs_daemon_hash_mux); | |
8bf2debd | 119 | rc = ecryptfs_exorcise_daemon(daemon); |
2ecaf55d | 120 | mutex_unlock(&ecryptfs_daemon_hash_mux); |
8bf2debd MH |
121 | if (rc) { |
122 | printk(KERN_CRIT "%s: Fatal error whilst attempting to " | |
123 | "shut down daemon; rc = [%d]. Please report this " | |
124 | "bug.\n", __func__, rc); | |
125 | BUG(); | |
126 | } | |
8bf2debd MH |
127 | return rc; |
128 | } | |
129 | ||
130 | /** | |
131 | * ecryptfs_send_miscdev | |
132 | * @data: Data to send to daemon; may be NULL | |
133 | * @data_size: Amount of data to send to daemon | |
134 | * @msg_ctx: Message context, which is used to handle the reply. If | |
135 | * this is NULL, then we do not expect a reply. | |
136 | * @msg_type: Type of message | |
137 | * @msg_flags: Flags for message | |
138 | * @daemon: eCryptfs daemon object | |
139 | * | |
140 | * Add msg_ctx to queue and then, if it exists, notify the blocked | |
141 | * miscdevess about the data being available. Must be called with | |
142 | * ecryptfs_daemon_hash_mux held. | |
143 | * | |
144 | * Returns zero on success; non-zero otherwise | |
145 | */ | |
146 | int ecryptfs_send_miscdev(char *data, size_t data_size, | |
147 | struct ecryptfs_msg_ctx *msg_ctx, u8 msg_type, | |
148 | u16 msg_flags, struct ecryptfs_daemon *daemon) | |
149 | { | |
60d65f1f | 150 | struct ecryptfs_message *msg; |
8bf2debd | 151 | |
60d65f1f | 152 | msg = kmalloc((sizeof(*msg) + data_size), GFP_KERNEL); |
1a0bba4f | 153 | if (!msg) |
60d65f1f | 154 | return -ENOMEM; |
60d65f1f TH |
155 | |
156 | mutex_lock(&msg_ctx->mux); | |
157 | msg_ctx->msg = msg; | |
8bf2debd MH |
158 | msg_ctx->msg->index = msg_ctx->index; |
159 | msg_ctx->msg->data_len = data_size; | |
160 | msg_ctx->type = msg_type; | |
57ea34d1 TH |
161 | memcpy(msg_ctx->msg->data, data, data_size); |
162 | msg_ctx->msg_size = (sizeof(*msg_ctx->msg) + data_size); | |
8bf2debd | 163 | list_add_tail(&msg_ctx->daemon_out_list, &daemon->msg_ctx_out_queue); |
60d65f1f TH |
164 | mutex_unlock(&msg_ctx->mux); |
165 | ||
166 | mutex_lock(&daemon->mux); | |
8bf2debd MH |
167 | daemon->num_queued_msg_ctx++; |
168 | wake_up_interruptible(&daemon->wait); | |
169 | mutex_unlock(&daemon->mux); | |
60d65f1f TH |
170 | |
171 | return 0; | |
8bf2debd MH |
172 | } |
173 | ||
48399c0b TH |
174 | /* |
175 | * miscdevfs packet format: | |
176 | * Octet 0: Type | |
177 | * Octets 1-4: network byte order msg_ctx->counter | |
178 | * Octets 5-N0: Size of struct ecryptfs_message to follow | |
179 | * Octets N0-N1: struct ecryptfs_message (including data) | |
180 | * | |
181 | * Octets 5-N1 not written if the packet type does not include a message | |
182 | */ | |
183 | #define PKT_TYPE_SIZE 1 | |
184 | #define PKT_CTR_SIZE 4 | |
185 | #define MIN_NON_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE) | |
186 | #define MIN_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE \ | |
187 | + ECRYPTFS_MIN_PKT_LEN_SIZE) | |
188 | /* 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES comes from tag 65 packet format */ | |
189 | #define MAX_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE \ | |
190 | + ECRYPTFS_MAX_PKT_LEN_SIZE \ | |
191 | + sizeof(struct ecryptfs_message) \ | |
192 | + 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) | |
193 | #define PKT_TYPE_OFFSET 0 | |
194 | #define PKT_CTR_OFFSET PKT_TYPE_SIZE | |
195 | #define PKT_LEN_OFFSET (PKT_TYPE_SIZE + PKT_CTR_SIZE) | |
196 | ||
8bf2debd MH |
197 | /** |
198 | * ecryptfs_miscdev_read - format and send message from queue | |
2ecaf55d | 199 | * @file: miscdevfs handle |
8bf2debd MH |
200 | * @buf: User buffer into which to copy the next message on the daemon queue |
201 | * @count: Amount of space available in @buf | |
202 | * @ppos: Offset in file (ignored) | |
203 | * | |
204 | * Pulls the most recent message from the daemon queue, formats it for | |
205 | * being sent via a miscdevfs handle, and copies it into @buf | |
206 | * | |
207 | * Returns the number of bytes copied into the user buffer | |
208 | */ | |
f66e883e | 209 | static ssize_t |
8bf2debd MH |
210 | ecryptfs_miscdev_read(struct file *file, char __user *buf, size_t count, |
211 | loff_t *ppos) | |
212 | { | |
2ecaf55d | 213 | struct ecryptfs_daemon *daemon = file->private_data; |
8bf2debd MH |
214 | struct ecryptfs_msg_ctx *msg_ctx; |
215 | size_t packet_length_size; | |
48399c0b | 216 | char packet_length[ECRYPTFS_MAX_PKT_LEN_SIZE]; |
8bf2debd MH |
217 | size_t i; |
218 | size_t total_length; | |
219 | int rc; | |
220 | ||
8bf2debd MH |
221 | mutex_lock(&daemon->mux); |
222 | if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) { | |
223 | rc = 0; | |
224 | printk(KERN_WARNING "%s: Attempt to read from zombified " | |
225 | "daemon\n", __func__); | |
226 | goto out_unlock_daemon; | |
227 | } | |
228 | if (daemon->flags & ECRYPTFS_DAEMON_IN_READ) { | |
229 | rc = 0; | |
230 | goto out_unlock_daemon; | |
231 | } | |
232 | /* This daemon will not go away so long as this flag is set */ | |
233 | daemon->flags |= ECRYPTFS_DAEMON_IN_READ; | |
8bf2debd MH |
234 | check_list: |
235 | if (list_empty(&daemon->msg_ctx_out_queue)) { | |
236 | mutex_unlock(&daemon->mux); | |
237 | rc = wait_event_interruptible( | |
238 | daemon->wait, !list_empty(&daemon->msg_ctx_out_queue)); | |
239 | mutex_lock(&daemon->mux); | |
240 | if (rc < 0) { | |
241 | rc = 0; | |
242 | goto out_unlock_daemon; | |
243 | } | |
244 | } | |
245 | if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) { | |
246 | rc = 0; | |
247 | goto out_unlock_daemon; | |
248 | } | |
249 | if (list_empty(&daemon->msg_ctx_out_queue)) { | |
250 | /* Something else jumped in since the | |
251 | * wait_event_interruptable() and removed the | |
252 | * message from the queue; try again */ | |
253 | goto check_list; | |
254 | } | |
8bf2debd MH |
255 | msg_ctx = list_first_entry(&daemon->msg_ctx_out_queue, |
256 | struct ecryptfs_msg_ctx, daemon_out_list); | |
257 | BUG_ON(!msg_ctx); | |
258 | mutex_lock(&msg_ctx->mux); | |
259 | if (msg_ctx->msg) { | |
260 | rc = ecryptfs_write_packet_length(packet_length, | |
261 | msg_ctx->msg_size, | |
262 | &packet_length_size); | |
263 | if (rc) { | |
264 | rc = 0; | |
265 | printk(KERN_WARNING "%s: Error writing packet length; " | |
266 | "rc = [%d]\n", __func__, rc); | |
267 | goto out_unlock_msg_ctx; | |
268 | } | |
269 | } else { | |
270 | packet_length_size = 0; | |
271 | msg_ctx->msg_size = 0; | |
272 | } | |
48399c0b TH |
273 | total_length = (PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_length_size |
274 | + msg_ctx->msg_size); | |
8bf2debd MH |
275 | if (count < total_length) { |
276 | rc = 0; | |
277 | printk(KERN_WARNING "%s: Only given user buffer of " | |
df261c52 | 278 | "size [%zd], but we need [%zd] to read the " |
8bf2debd MH |
279 | "pending message\n", __func__, count, total_length); |
280 | goto out_unlock_msg_ctx; | |
281 | } | |
79bc12a0 AV |
282 | rc = -EFAULT; |
283 | if (put_user(msg_ctx->type, buf)) | |
284 | goto out_unlock_msg_ctx; | |
48399c0b TH |
285 | if (put_user(cpu_to_be32(msg_ctx->counter), |
286 | (__be32 __user *)(&buf[PKT_CTR_OFFSET]))) | |
79bc12a0 | 287 | goto out_unlock_msg_ctx; |
48399c0b | 288 | i = PKT_TYPE_SIZE + PKT_CTR_SIZE; |
8bf2debd | 289 | if (msg_ctx->msg) { |
79bc12a0 AV |
290 | if (copy_to_user(&buf[i], packet_length, packet_length_size)) |
291 | goto out_unlock_msg_ctx; | |
8bf2debd | 292 | i += packet_length_size; |
79bc12a0 | 293 | if (copy_to_user(&buf[i], msg_ctx->msg, msg_ctx->msg_size)) |
8bf2debd | 294 | goto out_unlock_msg_ctx; |
8bf2debd MH |
295 | i += msg_ctx->msg_size; |
296 | } | |
297 | rc = i; | |
298 | list_del(&msg_ctx->daemon_out_list); | |
299 | kfree(msg_ctx->msg); | |
300 | msg_ctx->msg = NULL; | |
301 | /* We do not expect a reply from the userspace daemon for any | |
302 | * message type other than ECRYPTFS_MSG_REQUEST */ | |
303 | if (msg_ctx->type != ECRYPTFS_MSG_REQUEST) | |
304 | ecryptfs_msg_ctx_alloc_to_free(msg_ctx); | |
305 | out_unlock_msg_ctx: | |
306 | mutex_unlock(&msg_ctx->mux); | |
307 | out_unlock_daemon: | |
308 | daemon->flags &= ~ECRYPTFS_DAEMON_IN_READ; | |
309 | mutex_unlock(&daemon->mux); | |
310 | return rc; | |
311 | } | |
312 | ||
8bf2debd MH |
313 | /** |
314 | * ecryptfs_miscdev_response - miscdevess response to message previously sent to daemon | |
315 | * @data: Bytes comprising struct ecryptfs_message | |
316 | * @data_size: sizeof(struct ecryptfs_message) + data len | |
8bf2debd MH |
317 | * @seq: Sequence number for miscdev response packet |
318 | * | |
319 | * Returns zero on success; non-zero otherwise | |
320 | */ | |
2ecaf55d TH |
321 | static int ecryptfs_miscdev_response(struct ecryptfs_daemon *daemon, char *data, |
322 | size_t data_size, u32 seq) | |
8bf2debd MH |
323 | { |
324 | struct ecryptfs_message *msg = (struct ecryptfs_message *)data; | |
325 | int rc; | |
326 | ||
327 | if ((sizeof(*msg) + msg->data_len) != data_size) { | |
328 | printk(KERN_WARNING "%s: (sizeof(*msg) + msg->data_len) = " | |
df261c52 | 329 | "[%zd]; data_size = [%zd]. Invalid packet.\n", __func__, |
8bf2debd MH |
330 | (sizeof(*msg) + msg->data_len), data_size); |
331 | rc = -EINVAL; | |
332 | goto out; | |
333 | } | |
2ecaf55d | 334 | rc = ecryptfs_process_response(daemon, msg, seq); |
8bf2debd MH |
335 | if (rc) |
336 | printk(KERN_ERR | |
337 | "Error processing response message; rc = [%d]\n", rc); | |
338 | out: | |
339 | return rc; | |
340 | } | |
341 | ||
342 | /** | |
343 | * ecryptfs_miscdev_write - handle write to daemon miscdev handle | |
2ecaf55d | 344 | * @file: File for misc dev handle |
8bf2debd MH |
345 | * @buf: Buffer containing user data |
346 | * @count: Amount of data in @buf | |
347 | * @ppos: Pointer to offset in file (ignored) | |
348 | * | |
8bf2debd MH |
349 | * Returns the number of bytes read from @buf |
350 | */ | |
351 | static ssize_t | |
352 | ecryptfs_miscdev_write(struct file *file, const char __user *buf, | |
353 | size_t count, loff_t *ppos) | |
354 | { | |
79bc12a0 AV |
355 | __be32 counter_nbo; |
356 | u32 seq; | |
48399c0b | 357 | size_t packet_size, packet_size_length; |
8bf2debd | 358 | char *data; |
48399c0b | 359 | unsigned char packet_size_peek[ECRYPTFS_MAX_PKT_LEN_SIZE]; |
7f133504 | 360 | ssize_t rc; |
8bf2debd | 361 | |
db10e556 | 362 | if (count == 0) { |
7f133504 | 363 | return 0; |
48399c0b | 364 | } else if (count == MIN_NON_MSG_PKT_SIZE) { |
db10e556 TH |
365 | /* Likely a harmless MSG_HELO or MSG_QUIT - no packet length */ |
366 | goto memdup; | |
48399c0b | 367 | } else if (count < MIN_MSG_PKT_SIZE || count > MAX_MSG_PKT_SIZE) { |
db10e556 | 368 | printk(KERN_WARNING "%s: Acceptable packet size range is " |
0996b67d | 369 | "[%d-%zu], but amount of data written is [%zu].\n", |
48399c0b | 370 | __func__, MIN_MSG_PKT_SIZE, MAX_MSG_PKT_SIZE, count); |
db10e556 TH |
371 | return -EINVAL; |
372 | } | |
373 | ||
48399c0b | 374 | if (copy_from_user(packet_size_peek, &buf[PKT_LEN_OFFSET], |
db10e556 TH |
375 | sizeof(packet_size_peek))) { |
376 | printk(KERN_WARNING "%s: Error while inspecting packet size\n", | |
377 | __func__); | |
378 | return -EFAULT; | |
379 | } | |
380 | ||
381 | rc = ecryptfs_parse_packet_length(packet_size_peek, &packet_size, | |
382 | &packet_size_length); | |
383 | if (rc) { | |
384 | printk(KERN_WARNING "%s: Error parsing packet length; " | |
7f133504 | 385 | "rc = [%zd]\n", __func__, rc); |
db10e556 TH |
386 | return rc; |
387 | } | |
388 | ||
48399c0b TH |
389 | if ((PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_size_length + packet_size) |
390 | != count) { | |
db10e556 TH |
391 | printk(KERN_WARNING "%s: Invalid packet size [%zu]\n", __func__, |
392 | packet_size); | |
393 | return -EINVAL; | |
394 | } | |
fd56d242 | 395 | |
db10e556 | 396 | memdup: |
fd56d242 LZ |
397 | data = memdup_user(buf, count); |
398 | if (IS_ERR(data)) { | |
399 | printk(KERN_ERR "%s: memdup_user returned error [%ld]\n", | |
400 | __func__, PTR_ERR(data)); | |
7f133504 | 401 | return PTR_ERR(data); |
8bf2debd | 402 | } |
48399c0b | 403 | switch (data[PKT_TYPE_OFFSET]) { |
8bf2debd | 404 | case ECRYPTFS_MSG_RESPONSE: |
48399c0b TH |
405 | if (count < (MIN_MSG_PKT_SIZE |
406 | + sizeof(struct ecryptfs_message))) { | |
8bf2debd | 407 | printk(KERN_WARNING "%s: Minimum acceptable packet " |
df261c52 MH |
408 | "size is [%zd], but amount of data written is " |
409 | "only [%zd]. Discarding response packet.\n", | |
8bf2debd | 410 | __func__, |
48399c0b TH |
411 | (MIN_MSG_PKT_SIZE |
412 | + sizeof(struct ecryptfs_message)), count); | |
7f133504 | 413 | rc = -EINVAL; |
8bf2debd MH |
414 | goto out_free; |
415 | } | |
48399c0b | 416 | memcpy(&counter_nbo, &data[PKT_CTR_OFFSET], PKT_CTR_SIZE); |
8bf2debd | 417 | seq = be32_to_cpu(counter_nbo); |
2ecaf55d | 418 | rc = ecryptfs_miscdev_response(file->private_data, |
48399c0b | 419 | &data[PKT_LEN_OFFSET + packet_size_length], |
2ecaf55d | 420 | packet_size, seq); |
7f133504 | 421 | if (rc) { |
8bf2debd | 422 | printk(KERN_WARNING "%s: Failed to deliver miscdev " |
7f133504 | 423 | "response to requesting operation; rc = [%zd]\n", |
8bf2debd | 424 | __func__, rc); |
7f133504 TH |
425 | goto out_free; |
426 | } | |
8bf2debd MH |
427 | break; |
428 | case ECRYPTFS_MSG_HELO: | |
8bf2debd | 429 | case ECRYPTFS_MSG_QUIT: |
8bf2debd MH |
430 | break; |
431 | default: | |
432 | ecryptfs_printk(KERN_WARNING, "Dropping miscdev " | |
433 | "message of unrecognized type [%d]\n", | |
434 | data[0]); | |
7f133504 TH |
435 | rc = -EINVAL; |
436 | goto out_free; | |
8bf2debd | 437 | } |
7f133504 | 438 | rc = count; |
8bf2debd MH |
439 | out_free: |
440 | kfree(data); | |
7f133504 | 441 | return rc; |
8bf2debd MH |
442 | } |
443 | ||
444 | ||
445 | static const struct file_operations ecryptfs_miscdev_fops = { | |
52f21999 | 446 | .owner = THIS_MODULE, |
8bf2debd MH |
447 | .open = ecryptfs_miscdev_open, |
448 | .poll = ecryptfs_miscdev_poll, | |
449 | .read = ecryptfs_miscdev_read, | |
450 | .write = ecryptfs_miscdev_write, | |
451 | .release = ecryptfs_miscdev_release, | |
6038f373 | 452 | .llseek = noop_llseek, |
8bf2debd MH |
453 | }; |
454 | ||
455 | static struct miscdevice ecryptfs_miscdev = { | |
456 | .minor = MISC_DYNAMIC_MINOR, | |
457 | .name = "ecryptfs", | |
458 | .fops = &ecryptfs_miscdev_fops | |
459 | }; | |
460 | ||
461 | /** | |
462 | * ecryptfs_init_ecryptfs_miscdev | |
463 | * | |
464 | * Messages sent to the userspace daemon from the kernel are placed on | |
465 | * a queue associated with the daemon. The next read against the | |
466 | * miscdev handle by that daemon will return the oldest message placed | |
467 | * on the message queue for the daemon. | |
468 | * | |
469 | * Returns zero on success; non-zero otherwise | |
470 | */ | |
7371a382 | 471 | int __init ecryptfs_init_ecryptfs_miscdev(void) |
8bf2debd MH |
472 | { |
473 | int rc; | |
474 | ||
475 | atomic_set(&ecryptfs_num_miscdev_opens, 0); | |
8bf2debd MH |
476 | rc = misc_register(&ecryptfs_miscdev); |
477 | if (rc) | |
478 | printk(KERN_ERR "%s: Failed to register miscellaneous device " | |
479 | "for communications with userspace daemons; rc = [%d]\n", | |
480 | __func__, rc); | |
8bf2debd MH |
481 | return rc; |
482 | } | |
483 | ||
484 | /** | |
485 | * ecryptfs_destroy_ecryptfs_miscdev | |
486 | * | |
487 | * All of the daemons must be exorcised prior to calling this | |
488 | * function. | |
489 | */ | |
490 | void ecryptfs_destroy_ecryptfs_miscdev(void) | |
491 | { | |
492 | BUG_ON(atomic_read(&ecryptfs_num_miscdev_opens) != 0); | |
493 | misc_deregister(&ecryptfs_miscdev); | |
494 | } |