2 * eCryptfs: Linux filesystem encryption layer
4 * Copyright (C) 2004-2006 International Business Machines Corp.
5 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
6 * Tyler Hicks <tyhicks@ou.edu>
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License version
10 * 2 as published by the Free Software Foundation.
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
23 #include "ecryptfs_kernel.h"
25 LIST_HEAD(ecryptfs_msg_ctx_free_list);
26 LIST_HEAD(ecryptfs_msg_ctx_alloc_list);
27 struct mutex ecryptfs_msg_ctx_lists_mux;
29 struct hlist_head *ecryptfs_daemon_id_hash;
30 struct mutex ecryptfs_daemon_id_hash_mux;
31 int ecryptfs_hash_buckets;
33 unsigned int ecryptfs_msg_counter;
34 struct ecryptfs_msg_ctx *ecryptfs_msg_ctx_arr;
37 * ecryptfs_acquire_free_msg_ctx
38 * @msg_ctx: The context that was acquired from the free list
40 * Acquires a context element from the free list and locks the mutex
41 * on the context. Returns zero on success; non-zero on error or upon
42 * failure to acquire a free context element. Be sure to lock the
43 * list mutex before calling.
45 static int ecryptfs_acquire_free_msg_ctx(struct ecryptfs_msg_ctx **msg_ctx)
50 if (list_empty(&ecryptfs_msg_ctx_free_list)) {
51 ecryptfs_printk(KERN_WARNING, "The eCryptfs free "
52 "context list is empty. It may be helpful to "
53 "specify the ecryptfs_message_buf_len "
54 "parameter to be greater than the current "
55 "value of [%d]\n", ecryptfs_message_buf_len);
59 list_for_each(p, &ecryptfs_msg_ctx_free_list) {
60 *msg_ctx = list_entry(p, struct ecryptfs_msg_ctx, node);
61 if (mutex_trylock(&(*msg_ctx)->mux)) {
62 (*msg_ctx)->task = current;
73 * ecryptfs_msg_ctx_free_to_alloc
74 * @msg_ctx: The context to move from the free list to the alloc list
76 * Be sure to lock the list mutex and the context mutex before
79 static void ecryptfs_msg_ctx_free_to_alloc(struct ecryptfs_msg_ctx *msg_ctx)
81 list_move(&msg_ctx->node, &ecryptfs_msg_ctx_alloc_list);
82 msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_PENDING;
83 msg_ctx->counter = ++ecryptfs_msg_counter;
87 * ecryptfs_msg_ctx_alloc_to_free
88 * @msg_ctx: The context to move from the alloc list to the free list
90 * Be sure to lock the list mutex and the context mutex before
93 static void ecryptfs_msg_ctx_alloc_to_free(struct ecryptfs_msg_ctx *msg_ctx)
95 list_move(&(msg_ctx->node), &ecryptfs_msg_ctx_free_list);
98 msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_FREE;
102 * ecryptfs_find_daemon_id
103 * @uid: The user id which maps to the desired daemon id
104 * @id: If return value is zero, points to the desired daemon id
107 * Search the hash list for the given user id. Returns zero if the
108 * user id exists in the list; non-zero otherwise. The daemon id hash
109 * mutex should be held before calling this function.
111 static int ecryptfs_find_daemon_id(uid_t uid, struct ecryptfs_daemon_id **id)
113 struct hlist_node *elem;
116 hlist_for_each_entry(*id, elem,
117 &ecryptfs_daemon_id_hash[ecryptfs_uid_hash(uid)],
119 if ((*id)->uid == uid) {
129 static int ecryptfs_send_raw_message(unsigned int transport, u16 msg_type,
135 case ECRYPTFS_TRANSPORT_NETLINK:
136 rc = ecryptfs_send_netlink(NULL, 0, NULL, msg_type, 0, pid);
138 case ECRYPTFS_TRANSPORT_CONNECTOR:
139 case ECRYPTFS_TRANSPORT_RELAYFS:
147 * ecryptfs_process_helo
148 * @transport: The underlying transport (netlink, etc.)
149 * @uid: The user ID owner of the message
150 * @pid: The process ID for the userspace program that sent the
153 * Adds the uid and pid values to the daemon id hash. If a uid
154 * already has a daemon pid registered, the daemon will be
155 * unregistered before the new daemon id is put into the hash list.
156 * Returns zero after adding a new daemon id to the hash list;
157 * non-zero otherwise.
159 int ecryptfs_process_helo(unsigned int transport, uid_t uid, pid_t pid)
161 struct ecryptfs_daemon_id *new_id;
162 struct ecryptfs_daemon_id *old_id;
165 mutex_lock(&ecryptfs_daemon_id_hash_mux);
166 new_id = kmalloc(sizeof(*new_id), GFP_KERNEL);
169 ecryptfs_printk(KERN_ERR, "Failed to allocate memory; unable "
170 "to register daemon [%d] for user\n", pid, uid);
173 if (!ecryptfs_find_daemon_id(uid, &old_id)) {
174 printk(KERN_WARNING "Received request from user [%d] "
175 "to register daemon [%d]; unregistering daemon "
176 "[%d]\n", uid, pid, old_id->pid);
177 hlist_del(&old_id->id_chain);
178 rc = ecryptfs_send_raw_message(transport, ECRYPTFS_NLMSG_QUIT,
181 printk(KERN_WARNING "Failed to send QUIT "
182 "message to daemon [%d]; rc = [%d]\n",
188 hlist_add_head(&new_id->id_chain,
189 &ecryptfs_daemon_id_hash[ecryptfs_uid_hash(uid)]);
192 mutex_unlock(&ecryptfs_daemon_id_hash_mux);
197 * ecryptfs_process_quit
198 * @uid: The user ID owner of the message
199 * @pid: The process ID for the userspace program that sent the
202 * Deletes the corresponding daemon id for the given uid and pid, if
203 * it is the registered that is requesting the deletion. Returns zero
204 * after deleting the desired daemon id; non-zero otherwise.
206 int ecryptfs_process_quit(uid_t uid, pid_t pid)
208 struct ecryptfs_daemon_id *id;
211 mutex_lock(&ecryptfs_daemon_id_hash_mux);
212 if (ecryptfs_find_daemon_id(uid, &id)) {
214 ecryptfs_printk(KERN_ERR, "Received request from user [%d] to "
215 "unregister unrecognized daemon [%d]\n", uid,
219 if (id->pid != pid) {
221 ecryptfs_printk(KERN_WARNING, "Received request from user [%d] "
222 "with pid [%d] to unregister daemon [%d]\n",
226 hlist_del(&id->id_chain);
230 mutex_unlock(&ecryptfs_daemon_id_hash_mux);
235 * ecryptfs_process_reponse
236 * @msg: The ecryptfs message received; the caller should sanity check
238 * @pid: The process ID of the userspace application that sent the
240 * @seq: The sequence number of the message
242 * Processes a response message after sending a operation request to
243 * userspace. Returns zero upon delivery to desired context element;
244 * non-zero upon delivery failure or error.
246 int ecryptfs_process_response(struct ecryptfs_message *msg, uid_t uid,
249 struct ecryptfs_daemon_id *id;
250 struct ecryptfs_msg_ctx *msg_ctx;
254 if (msg->index >= ecryptfs_message_buf_len) {
256 ecryptfs_printk(KERN_ERR, "Attempt to reference "
257 "context buffer at index [%d]; maximum "
258 "allowable is [%d]\n", msg->index,
259 (ecryptfs_message_buf_len - 1));
262 msg_ctx = &ecryptfs_msg_ctx_arr[msg->index];
263 mutex_lock(&msg_ctx->mux);
264 if (ecryptfs_find_daemon_id(msg_ctx->task->euid, &id)) {
266 ecryptfs_printk(KERN_WARNING, "User [%d] received a "
267 "message response from process [%d] but does "
268 "not have a registered daemon\n",
269 msg_ctx->task->euid, pid);
272 if (msg_ctx->task->euid != uid) {
274 ecryptfs_printk(KERN_WARNING, "Received message from user "
275 "[%d]; expected message from user [%d]\n",
276 uid, msg_ctx->task->euid);
279 if (id->pid != pid) {
281 ecryptfs_printk(KERN_ERR, "User [%d] received a "
282 "message response from an unrecognized "
283 "process [%d]\n", msg_ctx->task->euid, pid);
286 if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_PENDING) {
288 ecryptfs_printk(KERN_WARNING, "Desired context element is not "
289 "pending a response\n");
291 } else if (msg_ctx->counter != seq) {
293 ecryptfs_printk(KERN_WARNING, "Invalid message sequence; "
294 "expected [%d]; received [%d]\n",
295 msg_ctx->counter, seq);
298 msg_size = sizeof(*msg) + msg->data_len;
299 msg_ctx->msg = kmalloc(msg_size, GFP_KERNEL);
302 ecryptfs_printk(KERN_ERR, "Failed to allocate memory\n");
305 memcpy(msg_ctx->msg, msg, msg_size);
306 msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_DONE;
309 wake_up_process(msg_ctx->task);
311 mutex_unlock(&msg_ctx->mux);
317 * ecryptfs_send_message
318 * @transport: The transport over which to send the message (i.e.,
320 * @data: The data to send
321 * @data_len: The length of data
322 * @msg_ctx: The message context allocated for the send
324 int ecryptfs_send_message(unsigned int transport, char *data, int data_len,
325 struct ecryptfs_msg_ctx **msg_ctx)
327 struct ecryptfs_daemon_id *id;
330 mutex_lock(&ecryptfs_daemon_id_hash_mux);
331 if (ecryptfs_find_daemon_id(current->euid, &id)) {
332 mutex_unlock(&ecryptfs_daemon_id_hash_mux);
334 ecryptfs_printk(KERN_ERR, "User [%d] does not have a daemon "
335 "registered\n", current->euid);
338 mutex_unlock(&ecryptfs_daemon_id_hash_mux);
339 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
340 rc = ecryptfs_acquire_free_msg_ctx(msg_ctx);
342 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
343 ecryptfs_printk(KERN_WARNING, "Could not claim a free "
344 "context element\n");
347 ecryptfs_msg_ctx_free_to_alloc(*msg_ctx);
348 mutex_unlock(&(*msg_ctx)->mux);
349 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
351 case ECRYPTFS_TRANSPORT_NETLINK:
352 rc = ecryptfs_send_netlink(data, data_len, *msg_ctx,
353 ECRYPTFS_NLMSG_REQUEST, 0, id->pid);
355 case ECRYPTFS_TRANSPORT_CONNECTOR:
356 case ECRYPTFS_TRANSPORT_RELAYFS:
361 printk(KERN_ERR "Error attempting to send message to userspace "
362 "daemon; rc = [%d]\n", rc);
369 * ecryptfs_wait_for_response
370 * @msg_ctx: The context that was assigned when sending a message
371 * @msg: The incoming message from userspace; not set if rc != 0
373 * Sleeps until awaken by ecryptfs_receive_message or until the amount
374 * of time exceeds ecryptfs_message_wait_timeout. If zero is
375 * returned, msg will point to a valid message from userspace; a
376 * non-zero value is returned upon failure to receive a message or an
379 int ecryptfs_wait_for_response(struct ecryptfs_msg_ctx *msg_ctx,
380 struct ecryptfs_message **msg)
382 signed long timeout = ecryptfs_message_wait_timeout * HZ;
386 timeout = schedule_timeout_interruptible(timeout);
387 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
388 mutex_lock(&msg_ctx->mux);
389 if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_DONE) {
391 mutex_unlock(&msg_ctx->mux);
392 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
400 ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
401 mutex_unlock(&msg_ctx->mux);
402 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
406 int ecryptfs_init_messaging(unsigned int transport)
411 if (ecryptfs_number_of_users > ECRYPTFS_MAX_NUM_USERS) {
412 ecryptfs_number_of_users = ECRYPTFS_MAX_NUM_USERS;
413 ecryptfs_printk(KERN_WARNING, "Specified number of users is "
414 "too large, defaulting to [%d] users\n",
415 ecryptfs_number_of_users);
417 mutex_init(&ecryptfs_daemon_id_hash_mux);
418 mutex_lock(&ecryptfs_daemon_id_hash_mux);
419 ecryptfs_hash_buckets = 0;
420 while (ecryptfs_number_of_users >> ++ecryptfs_hash_buckets);
421 ecryptfs_daemon_id_hash = kmalloc(sizeof(struct hlist_head)
422 * ecryptfs_hash_buckets, GFP_KERNEL);
423 if (!ecryptfs_daemon_id_hash) {
425 ecryptfs_printk(KERN_ERR, "Failed to allocate memory\n");
428 for (i = 0; i < ecryptfs_hash_buckets; i++)
429 INIT_HLIST_HEAD(&ecryptfs_daemon_id_hash[i]);
430 mutex_unlock(&ecryptfs_daemon_id_hash_mux);
432 ecryptfs_msg_ctx_arr = kmalloc((sizeof(struct ecryptfs_msg_ctx)
433 * ecryptfs_message_buf_len), GFP_KERNEL);
434 if (!ecryptfs_msg_ctx_arr) {
436 ecryptfs_printk(KERN_ERR, "Failed to allocate memory\n");
439 mutex_init(&ecryptfs_msg_ctx_lists_mux);
440 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
441 ecryptfs_msg_counter = 0;
442 for (i = 0; i < ecryptfs_message_buf_len; i++) {
443 INIT_LIST_HEAD(&ecryptfs_msg_ctx_arr[i].node);
444 mutex_init(&ecryptfs_msg_ctx_arr[i].mux);
445 mutex_lock(&ecryptfs_msg_ctx_arr[i].mux);
446 ecryptfs_msg_ctx_arr[i].index = i;
447 ecryptfs_msg_ctx_arr[i].state = ECRYPTFS_MSG_CTX_STATE_FREE;
448 ecryptfs_msg_ctx_arr[i].counter = 0;
449 ecryptfs_msg_ctx_arr[i].task = NULL;
450 ecryptfs_msg_ctx_arr[i].msg = NULL;
451 list_add_tail(&ecryptfs_msg_ctx_arr[i].node,
452 &ecryptfs_msg_ctx_free_list);
453 mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux);
455 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
457 case ECRYPTFS_TRANSPORT_NETLINK:
458 rc = ecryptfs_init_netlink();
460 ecryptfs_release_messaging(transport);
462 case ECRYPTFS_TRANSPORT_CONNECTOR:
463 case ECRYPTFS_TRANSPORT_RELAYFS:
471 void ecryptfs_release_messaging(unsigned int transport)
473 if (ecryptfs_msg_ctx_arr) {
476 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
477 for (i = 0; i < ecryptfs_message_buf_len; i++) {
478 mutex_lock(&ecryptfs_msg_ctx_arr[i].mux);
479 if (ecryptfs_msg_ctx_arr[i].msg)
480 kfree(ecryptfs_msg_ctx_arr[i].msg);
481 mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux);
483 kfree(ecryptfs_msg_ctx_arr);
484 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
486 if (ecryptfs_daemon_id_hash) {
487 struct hlist_node *elem;
488 struct ecryptfs_daemon_id *id;
491 mutex_lock(&ecryptfs_daemon_id_hash_mux);
492 for (i = 0; i < ecryptfs_hash_buckets; i++) {
493 hlist_for_each_entry(id, elem,
494 &ecryptfs_daemon_id_hash[i],
500 kfree(ecryptfs_daemon_id_hash);
501 mutex_unlock(&ecryptfs_daemon_id_hash_mux);
504 case ECRYPTFS_TRANSPORT_NETLINK:
505 ecryptfs_release_netlink();
507 case ECRYPTFS_TRANSPORT_CONNECTOR:
508 case ECRYPTFS_TRANSPORT_RELAYFS: