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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 (ignored)
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;
45 unsigned int mask = 0;
46 uid_t euid = current_euid();
47 int rc;
48
49 mutex_lock(&ecryptfs_daemon_hash_mux);
50 /* TODO: Just use file->private_data? */
51 rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
52 BUG_ON(rc || !daemon);
53 mutex_lock(&daemon->mux);
54 mutex_unlock(&ecryptfs_daemon_hash_mux);
55 if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
56 printk(KERN_WARNING "%s: Attempt to poll on zombified "
57 "daemon\n", __func__);
58 goto out_unlock_daemon;
59 }
60 if (daemon->flags & ECRYPTFS_DAEMON_IN_READ)
61 goto out_unlock_daemon;
62 if (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)
63 goto out_unlock_daemon;
64 daemon->flags |= ECRYPTFS_DAEMON_IN_POLL;
65 mutex_unlock(&daemon->mux);
66 poll_wait(file, &daemon->wait, pt);
67 mutex_lock(&daemon->mux);
68 if (!list_empty(&daemon->msg_ctx_out_queue))
69 mask |= POLLIN | POLLRDNORM;
70out_unlock_daemon:
71 daemon->flags &= ~ECRYPTFS_DAEMON_IN_POLL;
72 mutex_unlock(&daemon->mux);
73 return mask;
74}
75
76/**
77 * ecryptfs_miscdev_open
78 * @inode: inode of miscdev handle (ignored)
79 * @file: file for miscdev handle (ignored)
80 *
81 * Returns zero on success; non-zero otherwise
82 */
83static int
84ecryptfs_miscdev_open(struct inode *inode, struct file *file)
85{
86 struct ecryptfs_daemon *daemon = NULL;
87 uid_t euid = current_euid();
88 int rc;
89
90 mutex_lock(&ecryptfs_daemon_hash_mux);
91 rc = try_module_get(THIS_MODULE);
92 if (rc == 0) {
93 rc = -EIO;
94 printk(KERN_ERR "%s: Error attempting to increment module use "
95 "count; rc = [%d]\n", __func__, rc);
96 goto out_unlock_daemon_list;
97 }
98 rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
99 if (rc || !daemon) {
100 rc = ecryptfs_spawn_daemon(&daemon, euid, current_user_ns(),
101 task_pid(current));
102 if (rc) {
103 printk(KERN_ERR "%s: Error attempting to spawn daemon; "
104 "rc = [%d]\n", __func__, rc);
105 goto out_module_put_unlock_daemon_list;
106 }
107 }
108 mutex_lock(&daemon->mux);
109 if (daemon->pid != task_pid(current)) {
110 rc = -EINVAL;
111 printk(KERN_ERR "%s: pid [0x%p] has registered with euid [%d], "
112 "but pid [0x%p] has attempted to open the handle "
113 "instead\n", __func__, daemon->pid, daemon->euid,
114 task_pid(current));
115 goto out_unlock_daemon;
116 }
117 if (daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN) {
118 rc = -EBUSY;
119 printk(KERN_ERR "%s: Miscellaneous device handle may only be "
120 "opened once per daemon; pid [0x%p] already has this "
121 "handle open\n", __func__, daemon->pid);
122 goto out_unlock_daemon;
123 }
124 daemon->flags |= ECRYPTFS_DAEMON_MISCDEV_OPEN;
125 atomic_inc(&ecryptfs_num_miscdev_opens);
126out_unlock_daemon:
127 mutex_unlock(&daemon->mux);
128out_module_put_unlock_daemon_list:
129 if (rc)
130 module_put(THIS_MODULE);
131out_unlock_daemon_list:
132 mutex_unlock(&ecryptfs_daemon_hash_mux);
133 return rc;
134}
135
136/**
137 * ecryptfs_miscdev_release
138 * @inode: inode of fs/ecryptfs/euid handle (ignored)
139 * @file: file for fs/ecryptfs/euid handle (ignored)
140 *
141 * This keeps the daemon registered until the daemon sends another
142 * ioctl to fs/ecryptfs/ctl or until the kernel module unregisters.
143 *
144 * Returns zero on success; non-zero otherwise
145 */
146static int
147ecryptfs_miscdev_release(struct inode *inode, struct file *file)
148{
149 struct ecryptfs_daemon *daemon = NULL;
150 uid_t euid = current_euid();
151 int rc;
152
153 mutex_lock(&ecryptfs_daemon_hash_mux);
154 rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
155 BUG_ON(rc || !daemon);
156 mutex_lock(&daemon->mux);
157 BUG_ON(daemon->pid != task_pid(current));
158 BUG_ON(!(daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN));
159 daemon->flags &= ~ECRYPTFS_DAEMON_MISCDEV_OPEN;
160 atomic_dec(&ecryptfs_num_miscdev_opens);
161 mutex_unlock(&daemon->mux);
162 rc = ecryptfs_exorcise_daemon(daemon);
163 if (rc) {
164 printk(KERN_CRIT "%s: Fatal error whilst attempting to "
165 "shut down daemon; rc = [%d]. Please report this "
166 "bug.\n", __func__, rc);
167 BUG();
168 }
169 module_put(THIS_MODULE);
170 mutex_unlock(&ecryptfs_daemon_hash_mux);
171 return rc;
172}
173
174/**
175 * ecryptfs_send_miscdev
176 * @data: Data to send to daemon; may be NULL
177 * @data_size: Amount of data to send to daemon
178 * @msg_ctx: Message context, which is used to handle the reply. If
179 * this is NULL, then we do not expect a reply.
180 * @msg_type: Type of message
181 * @msg_flags: Flags for message
182 * @daemon: eCryptfs daemon object
183 *
184 * Add msg_ctx to queue and then, if it exists, notify the blocked
185 * miscdevess about the data being available. Must be called with
186 * ecryptfs_daemon_hash_mux held.
187 *
188 * Returns zero on success; non-zero otherwise
189 */
190int ecryptfs_send_miscdev(char *data, size_t data_size,
191 struct ecryptfs_msg_ctx *msg_ctx, u8 msg_type,
192 u16 msg_flags, struct ecryptfs_daemon *daemon)
193{
194 int rc = 0;
195
196 mutex_lock(&msg_ctx->mux);
197 msg_ctx->msg = kmalloc((sizeof(*msg_ctx->msg) + data_size),
198 GFP_KERNEL);
199 if (!msg_ctx->msg) {
200 rc = -ENOMEM;
201 printk(KERN_ERR "%s: Out of memory whilst attempting "
202 "to kmalloc(%zd, GFP_KERNEL)\n", __func__,
203 (sizeof(*msg_ctx->msg) + data_size));
204 goto out_unlock;
205 }
206 msg_ctx->msg->index = msg_ctx->index;
207 msg_ctx->msg->data_len = data_size;
208 msg_ctx->type = msg_type;
209 memcpy(msg_ctx->msg->data, data, data_size);
210 msg_ctx->msg_size = (sizeof(*msg_ctx->msg) + data_size);
211 mutex_lock(&daemon->mux);
212 list_add_tail(&msg_ctx->daemon_out_list, &daemon->msg_ctx_out_queue);
213 daemon->num_queued_msg_ctx++;
214 wake_up_interruptible(&daemon->wait);
215 mutex_unlock(&daemon->mux);
216out_unlock:
217 mutex_unlock(&msg_ctx->mux);
218 return rc;
219}
220
221/**
222 * ecryptfs_miscdev_read - format and send message from queue
223 * @file: fs/ecryptfs/euid miscdevfs handle (ignored)
224 * @buf: User buffer into which to copy the next message on the daemon queue
225 * @count: Amount of space available in @buf
226 * @ppos: Offset in file (ignored)
227 *
228 * Pulls the most recent message from the daemon queue, formats it for
229 * being sent via a miscdevfs handle, and copies it into @buf
230 *
231 * Returns the number of bytes copied into the user buffer
232 */
233static ssize_t
234ecryptfs_miscdev_read(struct file *file, char __user *buf, size_t count,
235 loff_t *ppos)
236{
237 struct ecryptfs_daemon *daemon;
238 struct ecryptfs_msg_ctx *msg_ctx;
239 size_t packet_length_size;
240 char packet_length[3];
241 size_t i;
242 size_t total_length;
243 uid_t euid = current_euid();
244 int rc;
245
246 mutex_lock(&ecryptfs_daemon_hash_mux);
247 /* TODO: Just use file->private_data? */
248 rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
249 BUG_ON(rc || !daemon);
250 mutex_lock(&daemon->mux);
251 if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
252 rc = 0;
253 mutex_unlock(&ecryptfs_daemon_hash_mux);
254 printk(KERN_WARNING "%s: Attempt to read from zombified "
255 "daemon\n", __func__);
256 goto out_unlock_daemon;
257 }
258 if (daemon->flags & ECRYPTFS_DAEMON_IN_READ) {
259 rc = 0;
260 mutex_unlock(&ecryptfs_daemon_hash_mux);
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);
266check_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(euid != daemon->euid);
288 BUG_ON(current_user_ns() != daemon->user_ns);
289 BUG_ON(task_pid(current) != daemon->pid);
290 msg_ctx = list_first_entry(&daemon->msg_ctx_out_queue,
291 struct ecryptfs_msg_ctx, daemon_out_list);
292 BUG_ON(!msg_ctx);
293 mutex_lock(&msg_ctx->mux);
294 if (msg_ctx->msg) {
295 rc = ecryptfs_write_packet_length(packet_length,
296 msg_ctx->msg_size,
297 &packet_length_size);
298 if (rc) {
299 rc = 0;
300 printk(KERN_WARNING "%s: Error writing packet length; "
301 "rc = [%d]\n", __func__, rc);
302 goto out_unlock_msg_ctx;
303 }
304 } else {
305 packet_length_size = 0;
306 msg_ctx->msg_size = 0;
307 }
308 /* miscdevfs packet format:
309 * Octet 0: Type
310 * Octets 1-4: network byte order msg_ctx->counter
311 * Octets 5-N0: Size of struct ecryptfs_message to follow
312 * Octets N0-N1: struct ecryptfs_message (including data)
313 *
314 * Octets 5-N1 not written if the packet type does not
315 * include a message */
316 total_length = (1 + 4 + packet_length_size + msg_ctx->msg_size);
317 if (count < total_length) {
318 rc = 0;
319 printk(KERN_WARNING "%s: Only given user buffer of "
320 "size [%zd], but we need [%zd] to read the "
321 "pending message\n", __func__, count, total_length);
322 goto out_unlock_msg_ctx;
323 }
324 rc = -EFAULT;
325 if (put_user(msg_ctx->type, buf))
326 goto out_unlock_msg_ctx;
327 if (put_user(cpu_to_be32(msg_ctx->counter), (__be32 __user *)(buf + 1)))
328 goto out_unlock_msg_ctx;
329 i = 5;
330 if (msg_ctx->msg) {
331 if (copy_to_user(&buf[i], packet_length, packet_length_size))
332 goto out_unlock_msg_ctx;
333 i += packet_length_size;
334 if (copy_to_user(&buf[i], msg_ctx->msg, msg_ctx->msg_size))
335 goto out_unlock_msg_ctx;
336 i += msg_ctx->msg_size;
337 }
338 rc = i;
339 list_del(&msg_ctx->daemon_out_list);
340 kfree(msg_ctx->msg);
341 msg_ctx->msg = NULL;
342 /* We do not expect a reply from the userspace daemon for any
343 * message type other than ECRYPTFS_MSG_REQUEST */
344 if (msg_ctx->type != ECRYPTFS_MSG_REQUEST)
345 ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
346out_unlock_msg_ctx:
347 mutex_unlock(&msg_ctx->mux);
348out_unlock_daemon:
349 daemon->flags &= ~ECRYPTFS_DAEMON_IN_READ;
350 mutex_unlock(&daemon->mux);
351 return rc;
352}
353
354/**
355 * ecryptfs_miscdev_response - miscdevess response to message previously sent to daemon
356 * @data: Bytes comprising struct ecryptfs_message
357 * @data_size: sizeof(struct ecryptfs_message) + data len
358 * @euid: Effective user id of miscdevess sending the miscdev response
359 * @user_ns: The namespace in which @euid applies
360 * @pid: Miscdevess id of miscdevess sending the miscdev response
361 * @seq: Sequence number for miscdev response packet
362 *
363 * Returns zero on success; non-zero otherwise
364 */
365static int ecryptfs_miscdev_response(char *data, size_t data_size,
366 uid_t euid, struct user_namespace *user_ns,
367 struct pid *pid, u32 seq)
368{
369 struct ecryptfs_message *msg = (struct ecryptfs_message *)data;
370 int rc;
371
372 if ((sizeof(*msg) + msg->data_len) != data_size) {
373 printk(KERN_WARNING "%s: (sizeof(*msg) + msg->data_len) = "
374 "[%zd]; data_size = [%zd]. Invalid packet.\n", __func__,
375 (sizeof(*msg) + msg->data_len), data_size);
376 rc = -EINVAL;
377 goto out;
378 }
379 rc = ecryptfs_process_response(msg, euid, user_ns, pid, seq);
380 if (rc)
381 printk(KERN_ERR
382 "Error processing response message; rc = [%d]\n", rc);
383out:
384 return rc;
385}
386
387/**
388 * ecryptfs_miscdev_write - handle write to daemon miscdev handle
389 * @file: File for misc dev handle (ignored)
390 * @buf: Buffer containing user data
391 * @count: Amount of data in @buf
392 * @ppos: Pointer to offset in file (ignored)
393 *
394 * miscdevfs packet format:
395 * Octet 0: Type
396 * Octets 1-4: network byte order msg_ctx->counter (0's for non-response)
397 * Octets 5-N0: Size of struct ecryptfs_message to follow
398 * Octets N0-N1: struct ecryptfs_message (including data)
399 *
400 * Returns the number of bytes read from @buf
401 */
402static ssize_t
403ecryptfs_miscdev_write(struct file *file, const char __user *buf,
404 size_t count, loff_t *ppos)
405{
406 __be32 counter_nbo;
407 u32 seq;
408 size_t packet_size, packet_size_length, i;
409 ssize_t sz = 0;
410 char *data;
411 uid_t euid = current_euid();
412 int rc;
413
414 if (count == 0)
415 goto out;
416
417 data = memdup_user(buf, count);
418 if (IS_ERR(data)) {
419 printk(KERN_ERR "%s: memdup_user returned error [%ld]\n",
420 __func__, PTR_ERR(data));
421 goto out;
422 }
423 sz = count;
424 i = 0;
425 switch (data[i++]) {
426 case ECRYPTFS_MSG_RESPONSE:
427 if (count < (1 + 4 + 1 + sizeof(struct ecryptfs_message))) {
428 printk(KERN_WARNING "%s: Minimum acceptable packet "
429 "size is [%zd], but amount of data written is "
430 "only [%zd]. Discarding response packet.\n",
431 __func__,
432 (1 + 4 + 1 + sizeof(struct ecryptfs_message)),
433 count);
434 goto out_free;
435 }
436 memcpy(&counter_nbo, &data[i], 4);
437 seq = be32_to_cpu(counter_nbo);
438 i += 4;
439 rc = ecryptfs_parse_packet_length(&data[i], &packet_size,
440 &packet_size_length);
441 if (rc) {
442 printk(KERN_WARNING "%s: Error parsing packet length; "
443 "rc = [%d]\n", __func__, rc);
444 goto out_free;
445 }
446 i += packet_size_length;
447 if ((1 + 4 + packet_size_length + packet_size) != count) {
448 printk(KERN_WARNING "%s: (1 + packet_size_length([%zd])"
449 " + packet_size([%zd]))([%zd]) != "
450 "count([%zd]). Invalid packet format.\n",
451 __func__, packet_size_length, packet_size,
452 (1 + packet_size_length + packet_size), count);
453 goto out_free;
454 }
455 rc = ecryptfs_miscdev_response(&data[i], packet_size,
456 euid, current_user_ns(),
457 task_pid(current), seq);
458 if (rc)
459 printk(KERN_WARNING "%s: Failed to deliver miscdev "
460 "response to requesting operation; rc = [%d]\n",
461 __func__, rc);
462 break;
463 case ECRYPTFS_MSG_HELO:
464 case ECRYPTFS_MSG_QUIT:
465 break;
466 default:
467 ecryptfs_printk(KERN_WARNING, "Dropping miscdev "
468 "message of unrecognized type [%d]\n",
469 data[0]);
470 break;
471 }
472out_free:
473 kfree(data);
474out:
475 return sz;
476}
477
478
479static const struct file_operations ecryptfs_miscdev_fops = {
480 .open = ecryptfs_miscdev_open,
481 .poll = ecryptfs_miscdev_poll,
482 .read = ecryptfs_miscdev_read,
483 .write = ecryptfs_miscdev_write,
484 .release = ecryptfs_miscdev_release,
485 .llseek = noop_llseek,
486};
487
488static struct miscdevice ecryptfs_miscdev = {
489 .minor = MISC_DYNAMIC_MINOR,
490 .name = "ecryptfs",
491 .fops = &ecryptfs_miscdev_fops
492};
493
494/**
495 * ecryptfs_init_ecryptfs_miscdev
496 *
497 * Messages sent to the userspace daemon from the kernel are placed on
498 * a queue associated with the daemon. The next read against the
499 * miscdev handle by that daemon will return the oldest message placed
500 * on the message queue for the daemon.
501 *
502 * Returns zero on success; non-zero otherwise
503 */
504int __init ecryptfs_init_ecryptfs_miscdev(void)
505{
506 int rc;
507
508 atomic_set(&ecryptfs_num_miscdev_opens, 0);
509 rc = misc_register(&ecryptfs_miscdev);
510 if (rc)
511 printk(KERN_ERR "%s: Failed to register miscellaneous device "
512 "for communications with userspace daemons; rc = [%d]\n",
513 __func__, rc);
514 return rc;
515}
516
517/**
518 * ecryptfs_destroy_ecryptfs_miscdev
519 *
520 * All of the daemons must be exorcised prior to calling this
521 * function.
522 */
523void ecryptfs_destroy_ecryptfs_miscdev(void)
524{
525 BUG_ON(atomic_read(&ecryptfs_num_miscdev_opens) != 0);
526 misc_deregister(&ecryptfs_miscdev);
527}
1// SPDX-License-Identifier: GPL-2.0-only
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>
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>
14#include <linux/slab.h>
15#include <linux/wait.h>
16#include <linux/module.h>
17#include "ecryptfs_kernel.h"
18
19static atomic_t ecryptfs_num_miscdev_opens;
20
21/**
22 * ecryptfs_miscdev_poll
23 * @file: dev file
24 * @pt: dev poll table (ignored)
25 *
26 * Returns the poll mask
27 */
28static __poll_t
29ecryptfs_miscdev_poll(struct file *file, poll_table *pt)
30{
31 struct ecryptfs_daemon *daemon = file->private_data;
32 __poll_t mask = 0;
33
34 mutex_lock(&daemon->mux);
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))
49 mask |= EPOLLIN | EPOLLRDNORM;
50out_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)
59 * @file: file for miscdev handle
60 *
61 * Returns zero on success; non-zero otherwise
62 */
63static int
64ecryptfs_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);
70 rc = ecryptfs_find_daemon_by_euid(&daemon);
71 if (!rc) {
72 rc = -EINVAL;
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);
79 goto out_unlock_daemon_list;
80 }
81 mutex_lock(&daemon->mux);
82 if (daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN) {
83 rc = -EBUSY;
84 goto out_unlock_daemon;
85 }
86 daemon->flags |= ECRYPTFS_DAEMON_MISCDEV_OPEN;
87 file->private_data = daemon;
88 atomic_inc(&ecryptfs_num_miscdev_opens);
89out_unlock_daemon:
90 mutex_unlock(&daemon->mux);
91out_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)
99 * @file: file for fs/ecryptfs/euid handle
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 */
106static int
107ecryptfs_miscdev_release(struct inode *inode, struct file *file)
108{
109 struct ecryptfs_daemon *daemon = file->private_data;
110 int rc;
111
112 mutex_lock(&daemon->mux);
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);
117
118 mutex_lock(&ecryptfs_daemon_hash_mux);
119 rc = ecryptfs_exorcise_daemon(daemon);
120 mutex_unlock(&ecryptfs_daemon_hash_mux);
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 }
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 */
146int 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{
150 struct ecryptfs_message *msg;
151
152 msg = kmalloc((sizeof(*msg) + data_size), GFP_KERNEL);
153 if (!msg)
154 return -ENOMEM;
155
156 mutex_lock(&msg_ctx->mux);
157 msg_ctx->msg = msg;
158 msg_ctx->msg->index = msg_ctx->index;
159 msg_ctx->msg->data_len = data_size;
160 msg_ctx->type = msg_type;
161 memcpy(msg_ctx->msg->data, data, data_size);
162 msg_ctx->msg_size = (sizeof(*msg_ctx->msg) + data_size);
163 list_add_tail(&msg_ctx->daemon_out_list, &daemon->msg_ctx_out_queue);
164 mutex_unlock(&msg_ctx->mux);
165
166 mutex_lock(&daemon->mux);
167 daemon->num_queued_msg_ctx++;
168 wake_up_interruptible(&daemon->wait);
169 mutex_unlock(&daemon->mux);
170
171 return 0;
172}
173
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
197/**
198 * ecryptfs_miscdev_read - format and send message from queue
199 * @file: miscdevfs handle
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 */
209static ssize_t
210ecryptfs_miscdev_read(struct file *file, char __user *buf, size_t count,
211 loff_t *ppos)
212{
213 struct ecryptfs_daemon *daemon = file->private_data;
214 struct ecryptfs_msg_ctx *msg_ctx;
215 size_t packet_length_size;
216 char packet_length[ECRYPTFS_MAX_PKT_LEN_SIZE];
217 size_t i;
218 size_t total_length;
219 int rc;
220
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;
234check_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 }
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 }
273 total_length = (PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_length_size
274 + msg_ctx->msg_size);
275 if (count < total_length) {
276 rc = 0;
277 printk(KERN_WARNING "%s: Only given user buffer of "
278 "size [%zd], but we need [%zd] to read the "
279 "pending message\n", __func__, count, total_length);
280 goto out_unlock_msg_ctx;
281 }
282 rc = -EFAULT;
283 if (put_user(msg_ctx->type, buf))
284 goto out_unlock_msg_ctx;
285 if (put_user(cpu_to_be32(msg_ctx->counter),
286 (__be32 __user *)(&buf[PKT_CTR_OFFSET])))
287 goto out_unlock_msg_ctx;
288 i = PKT_TYPE_SIZE + PKT_CTR_SIZE;
289 if (msg_ctx->msg) {
290 if (copy_to_user(&buf[i], packet_length, packet_length_size))
291 goto out_unlock_msg_ctx;
292 i += packet_length_size;
293 if (copy_to_user(&buf[i], msg_ctx->msg, msg_ctx->msg_size))
294 goto out_unlock_msg_ctx;
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);
305out_unlock_msg_ctx:
306 mutex_unlock(&msg_ctx->mux);
307out_unlock_daemon:
308 daemon->flags &= ~ECRYPTFS_DAEMON_IN_READ;
309 mutex_unlock(&daemon->mux);
310 return rc;
311}
312
313/**
314 * ecryptfs_miscdev_response - miscdevess response to message previously sent to daemon
315 * @daemon: eCryptfs daemon object
316 * @data: Bytes comprising struct ecryptfs_message
317 * @data_size: sizeof(struct ecryptfs_message) + data len
318 * @seq: Sequence number for miscdev response packet
319 *
320 * Returns zero on success; non-zero otherwise
321 */
322static int ecryptfs_miscdev_response(struct ecryptfs_daemon *daemon, char *data,
323 size_t data_size, u32 seq)
324{
325 struct ecryptfs_message *msg = (struct ecryptfs_message *)data;
326 int rc;
327
328 if ((sizeof(*msg) + msg->data_len) != data_size) {
329 printk(KERN_WARNING "%s: (sizeof(*msg) + msg->data_len) = "
330 "[%zd]; data_size = [%zd]. Invalid packet.\n", __func__,
331 (sizeof(*msg) + msg->data_len), data_size);
332 rc = -EINVAL;
333 goto out;
334 }
335 rc = ecryptfs_process_response(daemon, msg, seq);
336 if (rc)
337 printk(KERN_ERR
338 "Error processing response message; rc = [%d]\n", rc);
339out:
340 return rc;
341}
342
343/**
344 * ecryptfs_miscdev_write - handle write to daemon miscdev handle
345 * @file: File for misc dev handle
346 * @buf: Buffer containing user data
347 * @count: Amount of data in @buf
348 * @ppos: Pointer to offset in file (ignored)
349 *
350 * Returns the number of bytes read from @buf
351 */
352static ssize_t
353ecryptfs_miscdev_write(struct file *file, const char __user *buf,
354 size_t count, loff_t *ppos)
355{
356 __be32 counter_nbo;
357 u32 seq;
358 size_t packet_size, packet_size_length;
359 char *data;
360 unsigned char packet_size_peek[ECRYPTFS_MAX_PKT_LEN_SIZE];
361 ssize_t rc;
362
363 if (count == 0) {
364 return 0;
365 } else if (count == MIN_NON_MSG_PKT_SIZE) {
366 /* Likely a harmless MSG_HELO or MSG_QUIT - no packet length */
367 goto memdup;
368 } else if (count < MIN_MSG_PKT_SIZE || count > MAX_MSG_PKT_SIZE) {
369 printk(KERN_WARNING "%s: Acceptable packet size range is "
370 "[%d-%zu], but amount of data written is [%zu].\n",
371 __func__, MIN_MSG_PKT_SIZE, MAX_MSG_PKT_SIZE, count);
372 return -EINVAL;
373 }
374
375 if (copy_from_user(packet_size_peek, &buf[PKT_LEN_OFFSET],
376 sizeof(packet_size_peek))) {
377 printk(KERN_WARNING "%s: Error while inspecting packet size\n",
378 __func__);
379 return -EFAULT;
380 }
381
382 rc = ecryptfs_parse_packet_length(packet_size_peek, &packet_size,
383 &packet_size_length);
384 if (rc) {
385 printk(KERN_WARNING "%s: Error parsing packet length; "
386 "rc = [%zd]\n", __func__, rc);
387 return rc;
388 }
389
390 if ((PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_size_length + packet_size)
391 != count) {
392 printk(KERN_WARNING "%s: Invalid packet size [%zu]\n", __func__,
393 packet_size);
394 return -EINVAL;
395 }
396
397memdup:
398 data = memdup_user(buf, count);
399 if (IS_ERR(data)) {
400 printk(KERN_ERR "%s: memdup_user returned error [%ld]\n",
401 __func__, PTR_ERR(data));
402 return PTR_ERR(data);
403 }
404 switch (data[PKT_TYPE_OFFSET]) {
405 case ECRYPTFS_MSG_RESPONSE:
406 if (count < (MIN_MSG_PKT_SIZE
407 + sizeof(struct ecryptfs_message))) {
408 printk(KERN_WARNING "%s: Minimum acceptable packet "
409 "size is [%zd], but amount of data written is "
410 "only [%zd]. Discarding response packet.\n",
411 __func__,
412 (MIN_MSG_PKT_SIZE
413 + sizeof(struct ecryptfs_message)), count);
414 rc = -EINVAL;
415 goto out_free;
416 }
417 memcpy(&counter_nbo, &data[PKT_CTR_OFFSET], PKT_CTR_SIZE);
418 seq = be32_to_cpu(counter_nbo);
419 rc = ecryptfs_miscdev_response(file->private_data,
420 &data[PKT_LEN_OFFSET + packet_size_length],
421 packet_size, seq);
422 if (rc) {
423 printk(KERN_WARNING "%s: Failed to deliver miscdev "
424 "response to requesting operation; rc = [%zd]\n",
425 __func__, rc);
426 goto out_free;
427 }
428 break;
429 case ECRYPTFS_MSG_HELO:
430 case ECRYPTFS_MSG_QUIT:
431 break;
432 default:
433 ecryptfs_printk(KERN_WARNING, "Dropping miscdev "
434 "message of unrecognized type [%d]\n",
435 data[0]);
436 rc = -EINVAL;
437 goto out_free;
438 }
439 rc = count;
440out_free:
441 kfree(data);
442 return rc;
443}
444
445
446static const struct file_operations ecryptfs_miscdev_fops = {
447 .owner = THIS_MODULE,
448 .open = ecryptfs_miscdev_open,
449 .poll = ecryptfs_miscdev_poll,
450 .read = ecryptfs_miscdev_read,
451 .write = ecryptfs_miscdev_write,
452 .release = ecryptfs_miscdev_release,
453 .llseek = noop_llseek,
454};
455
456static struct miscdevice ecryptfs_miscdev = {
457 .minor = MISC_DYNAMIC_MINOR,
458 .name = "ecryptfs",
459 .fops = &ecryptfs_miscdev_fops
460};
461
462/**
463 * ecryptfs_init_ecryptfs_miscdev
464 *
465 * Messages sent to the userspace daemon from the kernel are placed on
466 * a queue associated with the daemon. The next read against the
467 * miscdev handle by that daemon will return the oldest message placed
468 * on the message queue for the daemon.
469 *
470 * Returns zero on success; non-zero otherwise
471 */
472int __init ecryptfs_init_ecryptfs_miscdev(void)
473{
474 int rc;
475
476 atomic_set(&ecryptfs_num_miscdev_opens, 0);
477 rc = misc_register(&ecryptfs_miscdev);
478 if (rc)
479 printk(KERN_ERR "%s: Failed to register miscellaneous device "
480 "for communications with userspace daemons; rc = [%d]\n",
481 __func__, rc);
482 return rc;
483}
484
485/**
486 * ecryptfs_destroy_ecryptfs_miscdev
487 *
488 * All of the daemons must be exorcised prior to calling this
489 * function.
490 */
491void ecryptfs_destroy_ecryptfs_miscdev(void)
492{
493 BUG_ON(atomic_read(&ecryptfs_num_miscdev_opens) != 0);
494 misc_deregister(&ecryptfs_miscdev);
495}