dm mpath: check if scsi_dh module already loaded before trying to load
[zen-stable.git] / fs / ecryptfs / miscdev.c
blob3a06f4043df42a811add69fd7ede7b582a94c347
1 /**
2 * eCryptfs: Linux filesystem encryption layer
4 * Copyright (C) 2008 International Business Machines Corp.
5 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
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.
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.
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.
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"
32 static atomic_t ecryptfs_num_miscdev_opens;
34 /**
35 * ecryptfs_miscdev_poll
36 * @file: dev file (ignored)
37 * @pt: dev poll table (ignored)
39 * Returns the poll mask
41 static unsigned int
42 ecryptfs_miscdev_poll(struct file *file, poll_table *pt)
44 struct ecryptfs_daemon *daemon;
45 unsigned int mask = 0;
46 uid_t euid = current_euid();
47 int rc;
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;
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;
70 out_unlock_daemon:
71 daemon->flags &= ~ECRYPTFS_DAEMON_IN_POLL;
72 mutex_unlock(&daemon->mux);
73 return mask;
76 /**
77 * ecryptfs_miscdev_open
78 * @inode: inode of miscdev handle (ignored)
79 * @file: file for miscdev handle (ignored)
81 * Returns zero on success; non-zero otherwise
83 static int
84 ecryptfs_miscdev_open(struct inode *inode, struct file *file)
86 struct ecryptfs_daemon *daemon = NULL;
87 uid_t euid = current_euid();
88 int rc;
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;
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;
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;
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;
124 daemon->flags |= ECRYPTFS_DAEMON_MISCDEV_OPEN;
125 atomic_inc(&ecryptfs_num_miscdev_opens);
126 out_unlock_daemon:
127 mutex_unlock(&daemon->mux);
128 out_module_put_unlock_daemon_list:
129 if (rc)
130 module_put(THIS_MODULE);
131 out_unlock_daemon_list:
132 mutex_unlock(&ecryptfs_daemon_hash_mux);
133 return rc;
137 * ecryptfs_miscdev_release
138 * @inode: inode of fs/ecryptfs/euid handle (ignored)
139 * @file: file for fs/ecryptfs/euid handle (ignored)
141 * This keeps the daemon registered until the daemon sends another
142 * ioctl to fs/ecryptfs/ctl or until the kernel module unregisters.
144 * Returns zero on success; non-zero otherwise
146 static int
147 ecryptfs_miscdev_release(struct inode *inode, struct file *file)
149 struct ecryptfs_daemon *daemon = NULL;
150 uid_t euid = current_euid();
151 int rc;
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();
169 module_put(THIS_MODULE);
170 mutex_unlock(&ecryptfs_daemon_hash_mux);
171 return rc;
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
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.
188 * Returns zero on success; non-zero otherwise
190 int 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)
194 int rc = 0;
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;
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);
216 out_unlock:
217 mutex_unlock(&msg_ctx->mux);
218 return rc;
222 * miscdevfs packet format:
223 * Octet 0: Type
224 * Octets 1-4: network byte order msg_ctx->counter
225 * Octets 5-N0: Size of struct ecryptfs_message to follow
226 * Octets N0-N1: struct ecryptfs_message (including data)
228 * Octets 5-N1 not written if the packet type does not include a message
230 #define PKT_TYPE_SIZE 1
231 #define PKT_CTR_SIZE 4
232 #define MIN_NON_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE)
233 #define MIN_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE \
234 + ECRYPTFS_MIN_PKT_LEN_SIZE)
235 /* 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES comes from tag 65 packet format */
236 #define MAX_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE \
237 + ECRYPTFS_MAX_PKT_LEN_SIZE \
238 + sizeof(struct ecryptfs_message) \
239 + 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES)
240 #define PKT_TYPE_OFFSET 0
241 #define PKT_CTR_OFFSET PKT_TYPE_SIZE
242 #define PKT_LEN_OFFSET (PKT_TYPE_SIZE + PKT_CTR_SIZE)
245 * ecryptfs_miscdev_read - format and send message from queue
246 * @file: fs/ecryptfs/euid miscdevfs handle (ignored)
247 * @buf: User buffer into which to copy the next message on the daemon queue
248 * @count: Amount of space available in @buf
249 * @ppos: Offset in file (ignored)
251 * Pulls the most recent message from the daemon queue, formats it for
252 * being sent via a miscdevfs handle, and copies it into @buf
254 * Returns the number of bytes copied into the user buffer
256 static ssize_t
257 ecryptfs_miscdev_read(struct file *file, char __user *buf, size_t count,
258 loff_t *ppos)
260 struct ecryptfs_daemon *daemon;
261 struct ecryptfs_msg_ctx *msg_ctx;
262 size_t packet_length_size;
263 char packet_length[ECRYPTFS_MAX_PKT_LEN_SIZE];
264 size_t i;
265 size_t total_length;
266 uid_t euid = current_euid();
267 int rc;
269 mutex_lock(&ecryptfs_daemon_hash_mux);
270 /* TODO: Just use file->private_data? */
271 rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
272 BUG_ON(rc || !daemon);
273 mutex_lock(&daemon->mux);
274 if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
275 rc = 0;
276 mutex_unlock(&ecryptfs_daemon_hash_mux);
277 printk(KERN_WARNING "%s: Attempt to read from zombified "
278 "daemon\n", __func__);
279 goto out_unlock_daemon;
281 if (daemon->flags & ECRYPTFS_DAEMON_IN_READ) {
282 rc = 0;
283 mutex_unlock(&ecryptfs_daemon_hash_mux);
284 goto out_unlock_daemon;
286 /* This daemon will not go away so long as this flag is set */
287 daemon->flags |= ECRYPTFS_DAEMON_IN_READ;
288 mutex_unlock(&ecryptfs_daemon_hash_mux);
289 check_list:
290 if (list_empty(&daemon->msg_ctx_out_queue)) {
291 mutex_unlock(&daemon->mux);
292 rc = wait_event_interruptible(
293 daemon->wait, !list_empty(&daemon->msg_ctx_out_queue));
294 mutex_lock(&daemon->mux);
295 if (rc < 0) {
296 rc = 0;
297 goto out_unlock_daemon;
300 if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
301 rc = 0;
302 goto out_unlock_daemon;
304 if (list_empty(&daemon->msg_ctx_out_queue)) {
305 /* Something else jumped in since the
306 * wait_event_interruptable() and removed the
307 * message from the queue; try again */
308 goto check_list;
310 BUG_ON(euid != daemon->euid);
311 BUG_ON(current_user_ns() != daemon->user_ns);
312 BUG_ON(task_pid(current) != daemon->pid);
313 msg_ctx = list_first_entry(&daemon->msg_ctx_out_queue,
314 struct ecryptfs_msg_ctx, daemon_out_list);
315 BUG_ON(!msg_ctx);
316 mutex_lock(&msg_ctx->mux);
317 if (msg_ctx->msg) {
318 rc = ecryptfs_write_packet_length(packet_length,
319 msg_ctx->msg_size,
320 &packet_length_size);
321 if (rc) {
322 rc = 0;
323 printk(KERN_WARNING "%s: Error writing packet length; "
324 "rc = [%d]\n", __func__, rc);
325 goto out_unlock_msg_ctx;
327 } else {
328 packet_length_size = 0;
329 msg_ctx->msg_size = 0;
331 total_length = (PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_length_size
332 + msg_ctx->msg_size);
333 if (count < total_length) {
334 rc = 0;
335 printk(KERN_WARNING "%s: Only given user buffer of "
336 "size [%zd], but we need [%zd] to read the "
337 "pending message\n", __func__, count, total_length);
338 goto out_unlock_msg_ctx;
340 rc = -EFAULT;
341 if (put_user(msg_ctx->type, buf))
342 goto out_unlock_msg_ctx;
343 if (put_user(cpu_to_be32(msg_ctx->counter),
344 (__be32 __user *)(&buf[PKT_CTR_OFFSET])))
345 goto out_unlock_msg_ctx;
346 i = PKT_TYPE_SIZE + PKT_CTR_SIZE;
347 if (msg_ctx->msg) {
348 if (copy_to_user(&buf[i], packet_length, packet_length_size))
349 goto out_unlock_msg_ctx;
350 i += packet_length_size;
351 if (copy_to_user(&buf[i], msg_ctx->msg, msg_ctx->msg_size))
352 goto out_unlock_msg_ctx;
353 i += msg_ctx->msg_size;
355 rc = i;
356 list_del(&msg_ctx->daemon_out_list);
357 kfree(msg_ctx->msg);
358 msg_ctx->msg = NULL;
359 /* We do not expect a reply from the userspace daemon for any
360 * message type other than ECRYPTFS_MSG_REQUEST */
361 if (msg_ctx->type != ECRYPTFS_MSG_REQUEST)
362 ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
363 out_unlock_msg_ctx:
364 mutex_unlock(&msg_ctx->mux);
365 out_unlock_daemon:
366 daemon->flags &= ~ECRYPTFS_DAEMON_IN_READ;
367 mutex_unlock(&daemon->mux);
368 return rc;
372 * ecryptfs_miscdev_response - miscdevess response to message previously sent to daemon
373 * @data: Bytes comprising struct ecryptfs_message
374 * @data_size: sizeof(struct ecryptfs_message) + data len
375 * @euid: Effective user id of miscdevess sending the miscdev response
376 * @user_ns: The namespace in which @euid applies
377 * @pid: Miscdevess id of miscdevess sending the miscdev response
378 * @seq: Sequence number for miscdev response packet
380 * Returns zero on success; non-zero otherwise
382 static int ecryptfs_miscdev_response(char *data, size_t data_size,
383 uid_t euid, struct user_namespace *user_ns,
384 struct pid *pid, u32 seq)
386 struct ecryptfs_message *msg = (struct ecryptfs_message *)data;
387 int rc;
389 if ((sizeof(*msg) + msg->data_len) != data_size) {
390 printk(KERN_WARNING "%s: (sizeof(*msg) + msg->data_len) = "
391 "[%zd]; data_size = [%zd]. Invalid packet.\n", __func__,
392 (sizeof(*msg) + msg->data_len), data_size);
393 rc = -EINVAL;
394 goto out;
396 rc = ecryptfs_process_response(msg, euid, user_ns, pid, seq);
397 if (rc)
398 printk(KERN_ERR
399 "Error processing response message; rc = [%d]\n", rc);
400 out:
401 return rc;
405 * ecryptfs_miscdev_write - handle write to daemon miscdev handle
406 * @file: File for misc dev handle (ignored)
407 * @buf: Buffer containing user data
408 * @count: Amount of data in @buf
409 * @ppos: Pointer to offset in file (ignored)
411 * Returns the number of bytes read from @buf
413 static ssize_t
414 ecryptfs_miscdev_write(struct file *file, const char __user *buf,
415 size_t count, loff_t *ppos)
417 __be32 counter_nbo;
418 u32 seq;
419 size_t packet_size, packet_size_length;
420 char *data;
421 uid_t euid = current_euid();
422 unsigned char packet_size_peek[ECRYPTFS_MAX_PKT_LEN_SIZE];
423 ssize_t rc;
425 if (count == 0) {
426 return 0;
427 } else if (count == MIN_NON_MSG_PKT_SIZE) {
428 /* Likely a harmless MSG_HELO or MSG_QUIT - no packet length */
429 goto memdup;
430 } else if (count < MIN_MSG_PKT_SIZE || count > MAX_MSG_PKT_SIZE) {
431 printk(KERN_WARNING "%s: Acceptable packet size range is "
432 "[%d-%zu], but amount of data written is [%zu].",
433 __func__, MIN_MSG_PKT_SIZE, MAX_MSG_PKT_SIZE, count);
434 return -EINVAL;
437 if (copy_from_user(packet_size_peek, &buf[PKT_LEN_OFFSET],
438 sizeof(packet_size_peek))) {
439 printk(KERN_WARNING "%s: Error while inspecting packet size\n",
440 __func__);
441 return -EFAULT;
444 rc = ecryptfs_parse_packet_length(packet_size_peek, &packet_size,
445 &packet_size_length);
446 if (rc) {
447 printk(KERN_WARNING "%s: Error parsing packet length; "
448 "rc = [%zd]\n", __func__, rc);
449 return rc;
452 if ((PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_size_length + packet_size)
453 != count) {
454 printk(KERN_WARNING "%s: Invalid packet size [%zu]\n", __func__,
455 packet_size);
456 return -EINVAL;
459 memdup:
460 data = memdup_user(buf, count);
461 if (IS_ERR(data)) {
462 printk(KERN_ERR "%s: memdup_user returned error [%ld]\n",
463 __func__, PTR_ERR(data));
464 return PTR_ERR(data);
466 switch (data[PKT_TYPE_OFFSET]) {
467 case ECRYPTFS_MSG_RESPONSE:
468 if (count < (MIN_MSG_PKT_SIZE
469 + sizeof(struct ecryptfs_message))) {
470 printk(KERN_WARNING "%s: Minimum acceptable packet "
471 "size is [%zd], but amount of data written is "
472 "only [%zd]. Discarding response packet.\n",
473 __func__,
474 (MIN_MSG_PKT_SIZE
475 + sizeof(struct ecryptfs_message)), count);
476 rc = -EINVAL;
477 goto out_free;
479 memcpy(&counter_nbo, &data[PKT_CTR_OFFSET], PKT_CTR_SIZE);
480 seq = be32_to_cpu(counter_nbo);
481 rc = ecryptfs_miscdev_response(
482 &data[PKT_LEN_OFFSET + packet_size_length],
483 packet_size, euid, current_user_ns(),
484 task_pid(current), seq);
485 if (rc) {
486 printk(KERN_WARNING "%s: Failed to deliver miscdev "
487 "response to requesting operation; rc = [%zd]\n",
488 __func__, rc);
489 goto out_free;
491 break;
492 case ECRYPTFS_MSG_HELO:
493 case ECRYPTFS_MSG_QUIT:
494 break;
495 default:
496 ecryptfs_printk(KERN_WARNING, "Dropping miscdev "
497 "message of unrecognized type [%d]\n",
498 data[0]);
499 rc = -EINVAL;
500 goto out_free;
502 rc = count;
503 out_free:
504 kfree(data);
505 return rc;
509 static const struct file_operations ecryptfs_miscdev_fops = {
510 .open = ecryptfs_miscdev_open,
511 .poll = ecryptfs_miscdev_poll,
512 .read = ecryptfs_miscdev_read,
513 .write = ecryptfs_miscdev_write,
514 .release = ecryptfs_miscdev_release,
515 .llseek = noop_llseek,
518 static struct miscdevice ecryptfs_miscdev = {
519 .minor = MISC_DYNAMIC_MINOR,
520 .name = "ecryptfs",
521 .fops = &ecryptfs_miscdev_fops
525 * ecryptfs_init_ecryptfs_miscdev
527 * Messages sent to the userspace daemon from the kernel are placed on
528 * a queue associated with the daemon. The next read against the
529 * miscdev handle by that daemon will return the oldest message placed
530 * on the message queue for the daemon.
532 * Returns zero on success; non-zero otherwise
534 int __init ecryptfs_init_ecryptfs_miscdev(void)
536 int rc;
538 atomic_set(&ecryptfs_num_miscdev_opens, 0);
539 rc = misc_register(&ecryptfs_miscdev);
540 if (rc)
541 printk(KERN_ERR "%s: Failed to register miscellaneous device "
542 "for communications with userspace daemons; rc = [%d]\n",
543 __func__, rc);
544 return rc;
548 * ecryptfs_destroy_ecryptfs_miscdev
550 * All of the daemons must be exorcised prior to calling this
551 * function.
553 void ecryptfs_destroy_ecryptfs_miscdev(void)
555 BUG_ON(atomic_read(&ecryptfs_num_miscdev_opens) != 0);
556 misc_deregister(&ecryptfs_miscdev);