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1/**
2 * eCryptfs: Linux filesystem encryption layer
3 *
4 * Copyright (C) 2004-2008 International Business Machines Corp.
5 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
6 * Tyler Hicks <tyhicks@ou.edu>
7 *
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.
11 *
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.
16 *
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
20 * 02111-1307, USA.
21 */
22#include <linux/sched.h>
23#include <linux/slab.h>
24#include <linux/user_namespace.h>
25#include <linux/nsproxy.h>
26#include "ecryptfs_kernel.h"
27
28static LIST_HEAD(ecryptfs_msg_ctx_free_list);
29static LIST_HEAD(ecryptfs_msg_ctx_alloc_list);
30static struct mutex ecryptfs_msg_ctx_lists_mux;
31
32static struct hlist_head *ecryptfs_daemon_hash;
33struct mutex ecryptfs_daemon_hash_mux;
34static int ecryptfs_hash_bits;
35#define ecryptfs_current_euid_hash(uid) \
36 hash_long((unsigned long)from_kuid(&init_user_ns, current_euid()), ecryptfs_hash_bits)
37
38static u32 ecryptfs_msg_counter;
39static struct ecryptfs_msg_ctx *ecryptfs_msg_ctx_arr;
40
41/**
42 * ecryptfs_acquire_free_msg_ctx
43 * @msg_ctx: The context that was acquired from the free list
44 *
45 * Acquires a context element from the free list and locks the mutex
46 * on the context. Sets the msg_ctx task to current. Returns zero on
47 * success; non-zero on error or upon failure to acquire a free
48 * context element. Must be called with ecryptfs_msg_ctx_lists_mux
49 * held.
50 */
51static int ecryptfs_acquire_free_msg_ctx(struct ecryptfs_msg_ctx **msg_ctx)
52{
53 struct list_head *p;
54 int rc;
55
56 if (list_empty(&ecryptfs_msg_ctx_free_list)) {
57 printk(KERN_WARNING "%s: The eCryptfs free "
58 "context list is empty. It may be helpful to "
59 "specify the ecryptfs_message_buf_len "
60 "parameter to be greater than the current "
61 "value of [%d]\n", __func__, ecryptfs_message_buf_len);
62 rc = -ENOMEM;
63 goto out;
64 }
65 list_for_each(p, &ecryptfs_msg_ctx_free_list) {
66 *msg_ctx = list_entry(p, struct ecryptfs_msg_ctx, node);
67 if (mutex_trylock(&(*msg_ctx)->mux)) {
68 (*msg_ctx)->task = current;
69 rc = 0;
70 goto out;
71 }
72 }
73 rc = -ENOMEM;
74out:
75 return rc;
76}
77
78/**
79 * ecryptfs_msg_ctx_free_to_alloc
80 * @msg_ctx: The context to move from the free list to the alloc list
81 *
82 * Must be called with ecryptfs_msg_ctx_lists_mux held.
83 */
84static void ecryptfs_msg_ctx_free_to_alloc(struct ecryptfs_msg_ctx *msg_ctx)
85{
86 list_move(&msg_ctx->node, &ecryptfs_msg_ctx_alloc_list);
87 msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_PENDING;
88 msg_ctx->counter = ++ecryptfs_msg_counter;
89}
90
91/**
92 * ecryptfs_msg_ctx_alloc_to_free
93 * @msg_ctx: The context to move from the alloc list to the free list
94 *
95 * Must be called with ecryptfs_msg_ctx_lists_mux held.
96 */
97void ecryptfs_msg_ctx_alloc_to_free(struct ecryptfs_msg_ctx *msg_ctx)
98{
99 list_move(&(msg_ctx->node), &ecryptfs_msg_ctx_free_list);
100 kfree(msg_ctx->msg);
101 msg_ctx->msg = NULL;
102 msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_FREE;
103}
104
105/**
106 * ecryptfs_find_daemon_by_euid
107 * @daemon: If return value is zero, points to the desired daemon pointer
108 *
109 * Must be called with ecryptfs_daemon_hash_mux held.
110 *
111 * Search the hash list for the current effective user id.
112 *
113 * Returns zero if the user id exists in the list; non-zero otherwise.
114 */
115int ecryptfs_find_daemon_by_euid(struct ecryptfs_daemon **daemon)
116{
117 int rc;
118
119 hlist_for_each_entry(*daemon,
120 &ecryptfs_daemon_hash[ecryptfs_current_euid_hash()],
121 euid_chain) {
122 if (uid_eq((*daemon)->file->f_cred->euid, current_euid())) {
123 rc = 0;
124 goto out;
125 }
126 }
127 rc = -EINVAL;
128out:
129 return rc;
130}
131
132/**
133 * ecryptfs_spawn_daemon - Create and initialize a new daemon struct
134 * @daemon: Pointer to set to newly allocated daemon struct
135 * @file: File used when opening /dev/ecryptfs
136 *
137 * Must be called ceremoniously while in possession of
138 * ecryptfs_sacred_daemon_hash_mux
139 *
140 * Returns zero on success; non-zero otherwise
141 */
142int
143ecryptfs_spawn_daemon(struct ecryptfs_daemon **daemon, struct file *file)
144{
145 int rc = 0;
146
147 (*daemon) = kzalloc(sizeof(**daemon), GFP_KERNEL);
148 if (!(*daemon)) {
149 rc = -ENOMEM;
150 printk(KERN_ERR "%s: Failed to allocate [%zd] bytes of "
151 "GFP_KERNEL memory\n", __func__, sizeof(**daemon));
152 goto out;
153 }
154 (*daemon)->file = file;
155 mutex_init(&(*daemon)->mux);
156 INIT_LIST_HEAD(&(*daemon)->msg_ctx_out_queue);
157 init_waitqueue_head(&(*daemon)->wait);
158 (*daemon)->num_queued_msg_ctx = 0;
159 hlist_add_head(&(*daemon)->euid_chain,
160 &ecryptfs_daemon_hash[ecryptfs_current_euid_hash()]);
161out:
162 return rc;
163}
164
165/**
166 * ecryptfs_exorcise_daemon - Destroy the daemon struct
167 *
168 * Must be called ceremoniously while in possession of
169 * ecryptfs_daemon_hash_mux and the daemon's own mux.
170 */
171int ecryptfs_exorcise_daemon(struct ecryptfs_daemon *daemon)
172{
173 struct ecryptfs_msg_ctx *msg_ctx, *msg_ctx_tmp;
174 int rc = 0;
175
176 mutex_lock(&daemon->mux);
177 if ((daemon->flags & ECRYPTFS_DAEMON_IN_READ)
178 || (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)) {
179 rc = -EBUSY;
180 mutex_unlock(&daemon->mux);
181 goto out;
182 }
183 list_for_each_entry_safe(msg_ctx, msg_ctx_tmp,
184 &daemon->msg_ctx_out_queue, daemon_out_list) {
185 list_del(&msg_ctx->daemon_out_list);
186 daemon->num_queued_msg_ctx--;
187 printk(KERN_WARNING "%s: Warning: dropping message that is in "
188 "the out queue of a dying daemon\n", __func__);
189 ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
190 }
191 hlist_del(&daemon->euid_chain);
192 mutex_unlock(&daemon->mux);
193 kzfree(daemon);
194out:
195 return rc;
196}
197
198/**
199 * ecryptfs_process_reponse
200 * @msg: The ecryptfs message received; the caller should sanity check
201 * msg->data_len and free the memory
202 * @seq: The sequence number of the message; must match the sequence
203 * number for the existing message context waiting for this
204 * response
205 *
206 * Processes a response message after sending an operation request to
207 * userspace. Some other process is awaiting this response. Before
208 * sending out its first communications, the other process allocated a
209 * msg_ctx from the ecryptfs_msg_ctx_arr at a particular index. The
210 * response message contains this index so that we can copy over the
211 * response message into the msg_ctx that the process holds a
212 * reference to. The other process is going to wake up, check to see
213 * that msg_ctx->state == ECRYPTFS_MSG_CTX_STATE_DONE, and then
214 * proceed to read off and process the response message. Returns zero
215 * upon delivery to desired context element; non-zero upon delivery
216 * failure or error.
217 *
218 * Returns zero on success; non-zero otherwise
219 */
220int ecryptfs_process_response(struct ecryptfs_daemon *daemon,
221 struct ecryptfs_message *msg, u32 seq)
222{
223 struct ecryptfs_msg_ctx *msg_ctx;
224 size_t msg_size;
225 int rc;
226
227 if (msg->index >= ecryptfs_message_buf_len) {
228 rc = -EINVAL;
229 printk(KERN_ERR "%s: Attempt to reference "
230 "context buffer at index [%d]; maximum "
231 "allowable is [%d]\n", __func__, msg->index,
232 (ecryptfs_message_buf_len - 1));
233 goto out;
234 }
235 msg_ctx = &ecryptfs_msg_ctx_arr[msg->index];
236 mutex_lock(&msg_ctx->mux);
237 if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_PENDING) {
238 rc = -EINVAL;
239 printk(KERN_WARNING "%s: Desired context element is not "
240 "pending a response\n", __func__);
241 goto unlock;
242 } else if (msg_ctx->counter != seq) {
243 rc = -EINVAL;
244 printk(KERN_WARNING "%s: Invalid message sequence; "
245 "expected [%d]; received [%d]\n", __func__,
246 msg_ctx->counter, seq);
247 goto unlock;
248 }
249 msg_size = (sizeof(*msg) + msg->data_len);
250 msg_ctx->msg = kmemdup(msg, msg_size, GFP_KERNEL);
251 if (!msg_ctx->msg) {
252 rc = -ENOMEM;
253 printk(KERN_ERR "%s: Failed to allocate [%zd] bytes of "
254 "GFP_KERNEL memory\n", __func__, msg_size);
255 goto unlock;
256 }
257 msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_DONE;
258 wake_up_process(msg_ctx->task);
259 rc = 0;
260unlock:
261 mutex_unlock(&msg_ctx->mux);
262out:
263 return rc;
264}
265
266/**
267 * ecryptfs_send_message_locked
268 * @data: The data to send
269 * @data_len: The length of data
270 * @msg_ctx: The message context allocated for the send
271 *
272 * Must be called with ecryptfs_daemon_hash_mux held.
273 *
274 * Returns zero on success; non-zero otherwise
275 */
276static int
277ecryptfs_send_message_locked(char *data, int data_len, u8 msg_type,
278 struct ecryptfs_msg_ctx **msg_ctx)
279{
280 struct ecryptfs_daemon *daemon;
281 int rc;
282
283 rc = ecryptfs_find_daemon_by_euid(&daemon);
284 if (rc) {
285 rc = -ENOTCONN;
286 goto out;
287 }
288 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
289 rc = ecryptfs_acquire_free_msg_ctx(msg_ctx);
290 if (rc) {
291 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
292 printk(KERN_WARNING "%s: Could not claim a free "
293 "context element\n", __func__);
294 goto out;
295 }
296 ecryptfs_msg_ctx_free_to_alloc(*msg_ctx);
297 mutex_unlock(&(*msg_ctx)->mux);
298 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
299 rc = ecryptfs_send_miscdev(data, data_len, *msg_ctx, msg_type, 0,
300 daemon);
301 if (rc)
302 printk(KERN_ERR "%s: Error attempting to send message to "
303 "userspace daemon; rc = [%d]\n", __func__, rc);
304out:
305 return rc;
306}
307
308/**
309 * ecryptfs_send_message
310 * @data: The data to send
311 * @data_len: The length of data
312 * @msg_ctx: The message context allocated for the send
313 *
314 * Grabs ecryptfs_daemon_hash_mux.
315 *
316 * Returns zero on success; non-zero otherwise
317 */
318int ecryptfs_send_message(char *data, int data_len,
319 struct ecryptfs_msg_ctx **msg_ctx)
320{
321 int rc;
322
323 mutex_lock(&ecryptfs_daemon_hash_mux);
324 rc = ecryptfs_send_message_locked(data, data_len, ECRYPTFS_MSG_REQUEST,
325 msg_ctx);
326 mutex_unlock(&ecryptfs_daemon_hash_mux);
327 return rc;
328}
329
330/**
331 * ecryptfs_wait_for_response
332 * @msg_ctx: The context that was assigned when sending a message
333 * @msg: The incoming message from userspace; not set if rc != 0
334 *
335 * Sleeps until awaken by ecryptfs_receive_message or until the amount
336 * of time exceeds ecryptfs_message_wait_timeout. If zero is
337 * returned, msg will point to a valid message from userspace; a
338 * non-zero value is returned upon failure to receive a message or an
339 * error occurs. Callee must free @msg on success.
340 */
341int ecryptfs_wait_for_response(struct ecryptfs_msg_ctx *msg_ctx,
342 struct ecryptfs_message **msg)
343{
344 signed long timeout = ecryptfs_message_wait_timeout * HZ;
345 int rc = 0;
346
347sleep:
348 timeout = schedule_timeout_interruptible(timeout);
349 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
350 mutex_lock(&msg_ctx->mux);
351 if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_DONE) {
352 if (timeout) {
353 mutex_unlock(&msg_ctx->mux);
354 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
355 goto sleep;
356 }
357 rc = -ENOMSG;
358 } else {
359 *msg = msg_ctx->msg;
360 msg_ctx->msg = NULL;
361 }
362 ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
363 mutex_unlock(&msg_ctx->mux);
364 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
365 return rc;
366}
367
368int __init ecryptfs_init_messaging(void)
369{
370 int i;
371 int rc = 0;
372
373 if (ecryptfs_number_of_users > ECRYPTFS_MAX_NUM_USERS) {
374 ecryptfs_number_of_users = ECRYPTFS_MAX_NUM_USERS;
375 printk(KERN_WARNING "%s: Specified number of users is "
376 "too large, defaulting to [%d] users\n", __func__,
377 ecryptfs_number_of_users);
378 }
379 mutex_init(&ecryptfs_daemon_hash_mux);
380 mutex_lock(&ecryptfs_daemon_hash_mux);
381 ecryptfs_hash_bits = 1;
382 while (ecryptfs_number_of_users >> ecryptfs_hash_bits)
383 ecryptfs_hash_bits++;
384 ecryptfs_daemon_hash = kmalloc((sizeof(struct hlist_head)
385 * (1 << ecryptfs_hash_bits)),
386 GFP_KERNEL);
387 if (!ecryptfs_daemon_hash) {
388 rc = -ENOMEM;
389 printk(KERN_ERR "%s: Failed to allocate memory\n", __func__);
390 mutex_unlock(&ecryptfs_daemon_hash_mux);
391 goto out;
392 }
393 for (i = 0; i < (1 << ecryptfs_hash_bits); i++)
394 INIT_HLIST_HEAD(&ecryptfs_daemon_hash[i]);
395 mutex_unlock(&ecryptfs_daemon_hash_mux);
396 ecryptfs_msg_ctx_arr = kmalloc((sizeof(struct ecryptfs_msg_ctx)
397 * ecryptfs_message_buf_len),
398 GFP_KERNEL);
399 if (!ecryptfs_msg_ctx_arr) {
400 rc = -ENOMEM;
401 printk(KERN_ERR "%s: Failed to allocate memory\n", __func__);
402 goto out;
403 }
404 mutex_init(&ecryptfs_msg_ctx_lists_mux);
405 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
406 ecryptfs_msg_counter = 0;
407 for (i = 0; i < ecryptfs_message_buf_len; i++) {
408 INIT_LIST_HEAD(&ecryptfs_msg_ctx_arr[i].node);
409 INIT_LIST_HEAD(&ecryptfs_msg_ctx_arr[i].daemon_out_list);
410 mutex_init(&ecryptfs_msg_ctx_arr[i].mux);
411 mutex_lock(&ecryptfs_msg_ctx_arr[i].mux);
412 ecryptfs_msg_ctx_arr[i].index = i;
413 ecryptfs_msg_ctx_arr[i].state = ECRYPTFS_MSG_CTX_STATE_FREE;
414 ecryptfs_msg_ctx_arr[i].counter = 0;
415 ecryptfs_msg_ctx_arr[i].task = NULL;
416 ecryptfs_msg_ctx_arr[i].msg = NULL;
417 list_add_tail(&ecryptfs_msg_ctx_arr[i].node,
418 &ecryptfs_msg_ctx_free_list);
419 mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux);
420 }
421 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
422 rc = ecryptfs_init_ecryptfs_miscdev();
423 if (rc)
424 ecryptfs_release_messaging();
425out:
426 return rc;
427}
428
429void ecryptfs_release_messaging(void)
430{
431 if (ecryptfs_msg_ctx_arr) {
432 int i;
433
434 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
435 for (i = 0; i < ecryptfs_message_buf_len; i++) {
436 mutex_lock(&ecryptfs_msg_ctx_arr[i].mux);
437 kfree(ecryptfs_msg_ctx_arr[i].msg);
438 mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux);
439 }
440 kfree(ecryptfs_msg_ctx_arr);
441 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
442 }
443 if (ecryptfs_daemon_hash) {
444 struct ecryptfs_daemon *daemon;
445 int i;
446
447 mutex_lock(&ecryptfs_daemon_hash_mux);
448 for (i = 0; i < (1 << ecryptfs_hash_bits); i++) {
449 int rc;
450
451 hlist_for_each_entry(daemon,
452 &ecryptfs_daemon_hash[i],
453 euid_chain) {
454 rc = ecryptfs_exorcise_daemon(daemon);
455 if (rc)
456 printk(KERN_ERR "%s: Error whilst "
457 "attempting to destroy daemon; "
458 "rc = [%d]. Dazed and confused, "
459 "but trying to continue.\n",
460 __func__, rc);
461 }
462 }
463 kfree(ecryptfs_daemon_hash);
464 mutex_unlock(&ecryptfs_daemon_hash_mux);
465 }
466 ecryptfs_destroy_ecryptfs_miscdev();
467 return;
468}
1/**
2 * eCryptfs: Linux filesystem encryption layer
3 *
4 * Copyright (C) 2004-2008 International Business Machines Corp.
5 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
6 * Tyler Hicks <tyhicks@ou.edu>
7 *
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.
11 *
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.
16 *
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
20 * 02111-1307, USA.
21 */
22#include <linux/sched.h>
23#include <linux/slab.h>
24#include <linux/user_namespace.h>
25#include <linux/nsproxy.h>
26#include "ecryptfs_kernel.h"
27
28static LIST_HEAD(ecryptfs_msg_ctx_free_list);
29static LIST_HEAD(ecryptfs_msg_ctx_alloc_list);
30static struct mutex ecryptfs_msg_ctx_lists_mux;
31
32static struct hlist_head *ecryptfs_daemon_hash;
33struct mutex ecryptfs_daemon_hash_mux;
34static int ecryptfs_hash_bits;
35#define ecryptfs_current_euid_hash(uid) \
36 hash_long((unsigned long)from_kuid(&init_user_ns, current_euid()), ecryptfs_hash_bits)
37
38static u32 ecryptfs_msg_counter;
39static struct ecryptfs_msg_ctx *ecryptfs_msg_ctx_arr;
40
41/**
42 * ecryptfs_acquire_free_msg_ctx
43 * @msg_ctx: The context that was acquired from the free list
44 *
45 * Acquires a context element from the free list and locks the mutex
46 * on the context. Sets the msg_ctx task to current. Returns zero on
47 * success; non-zero on error or upon failure to acquire a free
48 * context element. Must be called with ecryptfs_msg_ctx_lists_mux
49 * held.
50 */
51static int ecryptfs_acquire_free_msg_ctx(struct ecryptfs_msg_ctx **msg_ctx)
52{
53 struct list_head *p;
54 int rc;
55
56 if (list_empty(&ecryptfs_msg_ctx_free_list)) {
57 printk(KERN_WARNING "%s: The eCryptfs free "
58 "context list is empty. It may be helpful to "
59 "specify the ecryptfs_message_buf_len "
60 "parameter to be greater than the current "
61 "value of [%d]\n", __func__, ecryptfs_message_buf_len);
62 rc = -ENOMEM;
63 goto out;
64 }
65 list_for_each(p, &ecryptfs_msg_ctx_free_list) {
66 *msg_ctx = list_entry(p, struct ecryptfs_msg_ctx, node);
67 if (mutex_trylock(&(*msg_ctx)->mux)) {
68 (*msg_ctx)->task = current;
69 rc = 0;
70 goto out;
71 }
72 }
73 rc = -ENOMEM;
74out:
75 return rc;
76}
77
78/**
79 * ecryptfs_msg_ctx_free_to_alloc
80 * @msg_ctx: The context to move from the free list to the alloc list
81 *
82 * Must be called with ecryptfs_msg_ctx_lists_mux held.
83 */
84static void ecryptfs_msg_ctx_free_to_alloc(struct ecryptfs_msg_ctx *msg_ctx)
85{
86 list_move(&msg_ctx->node, &ecryptfs_msg_ctx_alloc_list);
87 msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_PENDING;
88 msg_ctx->counter = ++ecryptfs_msg_counter;
89}
90
91/**
92 * ecryptfs_msg_ctx_alloc_to_free
93 * @msg_ctx: The context to move from the alloc list to the free list
94 *
95 * Must be called with ecryptfs_msg_ctx_lists_mux held.
96 */
97void ecryptfs_msg_ctx_alloc_to_free(struct ecryptfs_msg_ctx *msg_ctx)
98{
99 list_move(&(msg_ctx->node), &ecryptfs_msg_ctx_free_list);
100 kfree(msg_ctx->msg);
101 msg_ctx->msg = NULL;
102 msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_FREE;
103}
104
105/**
106 * ecryptfs_find_daemon_by_euid
107 * @daemon: If return value is zero, points to the desired daemon pointer
108 *
109 * Must be called with ecryptfs_daemon_hash_mux held.
110 *
111 * Search the hash list for the current effective user id.
112 *
113 * Returns zero if the user id exists in the list; non-zero otherwise.
114 */
115int ecryptfs_find_daemon_by_euid(struct ecryptfs_daemon **daemon)
116{
117 int rc;
118
119 hlist_for_each_entry(*daemon,
120 &ecryptfs_daemon_hash[ecryptfs_current_euid_hash()],
121 euid_chain) {
122 if (uid_eq((*daemon)->file->f_cred->euid, current_euid())) {
123 rc = 0;
124 goto out;
125 }
126 }
127 rc = -EINVAL;
128out:
129 return rc;
130}
131
132/**
133 * ecryptfs_spawn_daemon - Create and initialize a new daemon struct
134 * @daemon: Pointer to set to newly allocated daemon struct
135 * @file: File used when opening /dev/ecryptfs
136 *
137 * Must be called ceremoniously while in possession of
138 * ecryptfs_sacred_daemon_hash_mux
139 *
140 * Returns zero on success; non-zero otherwise
141 */
142int
143ecryptfs_spawn_daemon(struct ecryptfs_daemon **daemon, struct file *file)
144{
145 int rc = 0;
146
147 (*daemon) = kzalloc(sizeof(**daemon), GFP_KERNEL);
148 if (!(*daemon)) {
149 rc = -ENOMEM;
150 goto out;
151 }
152 (*daemon)->file = file;
153 mutex_init(&(*daemon)->mux);
154 INIT_LIST_HEAD(&(*daemon)->msg_ctx_out_queue);
155 init_waitqueue_head(&(*daemon)->wait);
156 (*daemon)->num_queued_msg_ctx = 0;
157 hlist_add_head(&(*daemon)->euid_chain,
158 &ecryptfs_daemon_hash[ecryptfs_current_euid_hash()]);
159out:
160 return rc;
161}
162
163/**
164 * ecryptfs_exorcise_daemon - Destroy the daemon struct
165 *
166 * Must be called ceremoniously while in possession of
167 * ecryptfs_daemon_hash_mux and the daemon's own mux.
168 */
169int ecryptfs_exorcise_daemon(struct ecryptfs_daemon *daemon)
170{
171 struct ecryptfs_msg_ctx *msg_ctx, *msg_ctx_tmp;
172 int rc = 0;
173
174 mutex_lock(&daemon->mux);
175 if ((daemon->flags & ECRYPTFS_DAEMON_IN_READ)
176 || (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)) {
177 rc = -EBUSY;
178 mutex_unlock(&daemon->mux);
179 goto out;
180 }
181 list_for_each_entry_safe(msg_ctx, msg_ctx_tmp,
182 &daemon->msg_ctx_out_queue, daemon_out_list) {
183 list_del(&msg_ctx->daemon_out_list);
184 daemon->num_queued_msg_ctx--;
185 printk(KERN_WARNING "%s: Warning: dropping message that is in "
186 "the out queue of a dying daemon\n", __func__);
187 ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
188 }
189 hlist_del(&daemon->euid_chain);
190 mutex_unlock(&daemon->mux);
191 kzfree(daemon);
192out:
193 return rc;
194}
195
196/**
197 * ecryptfs_process_reponse
198 * @msg: The ecryptfs message received; the caller should sanity check
199 * msg->data_len and free the memory
200 * @seq: The sequence number of the message; must match the sequence
201 * number for the existing message context waiting for this
202 * response
203 *
204 * Processes a response message after sending an operation request to
205 * userspace. Some other process is awaiting this response. Before
206 * sending out its first communications, the other process allocated a
207 * msg_ctx from the ecryptfs_msg_ctx_arr at a particular index. The
208 * response message contains this index so that we can copy over the
209 * response message into the msg_ctx that the process holds a
210 * reference to. The other process is going to wake up, check to see
211 * that msg_ctx->state == ECRYPTFS_MSG_CTX_STATE_DONE, and then
212 * proceed to read off and process the response message. Returns zero
213 * upon delivery to desired context element; non-zero upon delivery
214 * failure or error.
215 *
216 * Returns zero on success; non-zero otherwise
217 */
218int ecryptfs_process_response(struct ecryptfs_daemon *daemon,
219 struct ecryptfs_message *msg, u32 seq)
220{
221 struct ecryptfs_msg_ctx *msg_ctx;
222 size_t msg_size;
223 int rc;
224
225 if (msg->index >= ecryptfs_message_buf_len) {
226 rc = -EINVAL;
227 printk(KERN_ERR "%s: Attempt to reference "
228 "context buffer at index [%d]; maximum "
229 "allowable is [%d]\n", __func__, msg->index,
230 (ecryptfs_message_buf_len - 1));
231 goto out;
232 }
233 msg_ctx = &ecryptfs_msg_ctx_arr[msg->index];
234 mutex_lock(&msg_ctx->mux);
235 if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_PENDING) {
236 rc = -EINVAL;
237 printk(KERN_WARNING "%s: Desired context element is not "
238 "pending a response\n", __func__);
239 goto unlock;
240 } else if (msg_ctx->counter != seq) {
241 rc = -EINVAL;
242 printk(KERN_WARNING "%s: Invalid message sequence; "
243 "expected [%d]; received [%d]\n", __func__,
244 msg_ctx->counter, seq);
245 goto unlock;
246 }
247 msg_size = (sizeof(*msg) + msg->data_len);
248 msg_ctx->msg = kmemdup(msg, msg_size, GFP_KERNEL);
249 if (!msg_ctx->msg) {
250 rc = -ENOMEM;
251 goto unlock;
252 }
253 msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_DONE;
254 wake_up_process(msg_ctx->task);
255 rc = 0;
256unlock:
257 mutex_unlock(&msg_ctx->mux);
258out:
259 return rc;
260}
261
262/**
263 * ecryptfs_send_message_locked
264 * @data: The data to send
265 * @data_len: The length of data
266 * @msg_ctx: The message context allocated for the send
267 *
268 * Must be called with ecryptfs_daemon_hash_mux held.
269 *
270 * Returns zero on success; non-zero otherwise
271 */
272static int
273ecryptfs_send_message_locked(char *data, int data_len, u8 msg_type,
274 struct ecryptfs_msg_ctx **msg_ctx)
275{
276 struct ecryptfs_daemon *daemon;
277 int rc;
278
279 rc = ecryptfs_find_daemon_by_euid(&daemon);
280 if (rc) {
281 rc = -ENOTCONN;
282 goto out;
283 }
284 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
285 rc = ecryptfs_acquire_free_msg_ctx(msg_ctx);
286 if (rc) {
287 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
288 printk(KERN_WARNING "%s: Could not claim a free "
289 "context element\n", __func__);
290 goto out;
291 }
292 ecryptfs_msg_ctx_free_to_alloc(*msg_ctx);
293 mutex_unlock(&(*msg_ctx)->mux);
294 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
295 rc = ecryptfs_send_miscdev(data, data_len, *msg_ctx, msg_type, 0,
296 daemon);
297 if (rc)
298 printk(KERN_ERR "%s: Error attempting to send message to "
299 "userspace daemon; rc = [%d]\n", __func__, rc);
300out:
301 return rc;
302}
303
304/**
305 * ecryptfs_send_message
306 * @data: The data to send
307 * @data_len: The length of data
308 * @msg_ctx: The message context allocated for the send
309 *
310 * Grabs ecryptfs_daemon_hash_mux.
311 *
312 * Returns zero on success; non-zero otherwise
313 */
314int ecryptfs_send_message(char *data, int data_len,
315 struct ecryptfs_msg_ctx **msg_ctx)
316{
317 int rc;
318
319 mutex_lock(&ecryptfs_daemon_hash_mux);
320 rc = ecryptfs_send_message_locked(data, data_len, ECRYPTFS_MSG_REQUEST,
321 msg_ctx);
322 mutex_unlock(&ecryptfs_daemon_hash_mux);
323 return rc;
324}
325
326/**
327 * ecryptfs_wait_for_response
328 * @msg_ctx: The context that was assigned when sending a message
329 * @msg: The incoming message from userspace; not set if rc != 0
330 *
331 * Sleeps until awaken by ecryptfs_receive_message or until the amount
332 * of time exceeds ecryptfs_message_wait_timeout. If zero is
333 * returned, msg will point to a valid message from userspace; a
334 * non-zero value is returned upon failure to receive a message or an
335 * error occurs. Callee must free @msg on success.
336 */
337int ecryptfs_wait_for_response(struct ecryptfs_msg_ctx *msg_ctx,
338 struct ecryptfs_message **msg)
339{
340 signed long timeout = ecryptfs_message_wait_timeout * HZ;
341 int rc = 0;
342
343sleep:
344 timeout = schedule_timeout_interruptible(timeout);
345 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
346 mutex_lock(&msg_ctx->mux);
347 if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_DONE) {
348 if (timeout) {
349 mutex_unlock(&msg_ctx->mux);
350 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
351 goto sleep;
352 }
353 rc = -ENOMSG;
354 } else {
355 *msg = msg_ctx->msg;
356 msg_ctx->msg = NULL;
357 }
358 ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
359 mutex_unlock(&msg_ctx->mux);
360 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
361 return rc;
362}
363
364int __init ecryptfs_init_messaging(void)
365{
366 int i;
367 int rc = 0;
368
369 if (ecryptfs_number_of_users > ECRYPTFS_MAX_NUM_USERS) {
370 ecryptfs_number_of_users = ECRYPTFS_MAX_NUM_USERS;
371 printk(KERN_WARNING "%s: Specified number of users is "
372 "too large, defaulting to [%d] users\n", __func__,
373 ecryptfs_number_of_users);
374 }
375 mutex_init(&ecryptfs_daemon_hash_mux);
376 mutex_lock(&ecryptfs_daemon_hash_mux);
377 ecryptfs_hash_bits = 1;
378 while (ecryptfs_number_of_users >> ecryptfs_hash_bits)
379 ecryptfs_hash_bits++;
380 ecryptfs_daemon_hash = kmalloc((sizeof(struct hlist_head)
381 * (1 << ecryptfs_hash_bits)),
382 GFP_KERNEL);
383 if (!ecryptfs_daemon_hash) {
384 rc = -ENOMEM;
385 mutex_unlock(&ecryptfs_daemon_hash_mux);
386 goto out;
387 }
388 for (i = 0; i < (1 << ecryptfs_hash_bits); i++)
389 INIT_HLIST_HEAD(&ecryptfs_daemon_hash[i]);
390 mutex_unlock(&ecryptfs_daemon_hash_mux);
391 ecryptfs_msg_ctx_arr = kmalloc((sizeof(struct ecryptfs_msg_ctx)
392 * ecryptfs_message_buf_len),
393 GFP_KERNEL);
394 if (!ecryptfs_msg_ctx_arr) {
395 rc = -ENOMEM;
396 goto out;
397 }
398 mutex_init(&ecryptfs_msg_ctx_lists_mux);
399 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
400 ecryptfs_msg_counter = 0;
401 for (i = 0; i < ecryptfs_message_buf_len; i++) {
402 INIT_LIST_HEAD(&ecryptfs_msg_ctx_arr[i].node);
403 INIT_LIST_HEAD(&ecryptfs_msg_ctx_arr[i].daemon_out_list);
404 mutex_init(&ecryptfs_msg_ctx_arr[i].mux);
405 mutex_lock(&ecryptfs_msg_ctx_arr[i].mux);
406 ecryptfs_msg_ctx_arr[i].index = i;
407 ecryptfs_msg_ctx_arr[i].state = ECRYPTFS_MSG_CTX_STATE_FREE;
408 ecryptfs_msg_ctx_arr[i].counter = 0;
409 ecryptfs_msg_ctx_arr[i].task = NULL;
410 ecryptfs_msg_ctx_arr[i].msg = NULL;
411 list_add_tail(&ecryptfs_msg_ctx_arr[i].node,
412 &ecryptfs_msg_ctx_free_list);
413 mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux);
414 }
415 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
416 rc = ecryptfs_init_ecryptfs_miscdev();
417 if (rc)
418 ecryptfs_release_messaging();
419out:
420 return rc;
421}
422
423void ecryptfs_release_messaging(void)
424{
425 if (ecryptfs_msg_ctx_arr) {
426 int i;
427
428 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
429 for (i = 0; i < ecryptfs_message_buf_len; i++) {
430 mutex_lock(&ecryptfs_msg_ctx_arr[i].mux);
431 kfree(ecryptfs_msg_ctx_arr[i].msg);
432 mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux);
433 }
434 kfree(ecryptfs_msg_ctx_arr);
435 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
436 }
437 if (ecryptfs_daemon_hash) {
438 struct ecryptfs_daemon *daemon;
439 struct hlist_node *n;
440 int i;
441
442 mutex_lock(&ecryptfs_daemon_hash_mux);
443 for (i = 0; i < (1 << ecryptfs_hash_bits); i++) {
444 int rc;
445
446 hlist_for_each_entry_safe(daemon, n,
447 &ecryptfs_daemon_hash[i],
448 euid_chain) {
449 rc = ecryptfs_exorcise_daemon(daemon);
450 if (rc)
451 printk(KERN_ERR "%s: Error whilst "
452 "attempting to destroy daemon; "
453 "rc = [%d]. Dazed and confused, "
454 "but trying to continue.\n",
455 __func__, rc);
456 }
457 }
458 kfree(ecryptfs_daemon_hash);
459 mutex_unlock(&ecryptfs_daemon_hash_mux);
460 }
461 ecryptfs_destroy_ecryptfs_miscdev();
462 return;
463}