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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * eCryptfs: Linux filesystem encryption layer
4 *
5 * Copyright (C) 2004-2008 International Business Machines Corp.
6 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
7 * Tyler Hicks <code@tyhicks.com>
8 */
9#include <linux/sched.h>
10#include <linux/slab.h>
11#include <linux/user_namespace.h>
12#include <linux/nsproxy.h>
13#include "ecryptfs_kernel.h"
14
15static LIST_HEAD(ecryptfs_msg_ctx_free_list);
16static LIST_HEAD(ecryptfs_msg_ctx_alloc_list);
17static DEFINE_MUTEX(ecryptfs_msg_ctx_lists_mux);
18
19static struct hlist_head *ecryptfs_daemon_hash;
20DEFINE_MUTEX(ecryptfs_daemon_hash_mux);
21static int ecryptfs_hash_bits;
22#define ecryptfs_current_euid_hash(uid) \
23 hash_long((unsigned long)from_kuid(&init_user_ns, current_euid()), ecryptfs_hash_bits)
24
25static u32 ecryptfs_msg_counter;
26static struct ecryptfs_msg_ctx *ecryptfs_msg_ctx_arr;
27
28/**
29 * ecryptfs_acquire_free_msg_ctx
30 * @msg_ctx: The context that was acquired from the free list
31 *
32 * Acquires a context element from the free list and locks the mutex
33 * on the context. Sets the msg_ctx task to current. Returns zero on
34 * success; non-zero on error or upon failure to acquire a free
35 * context element. Must be called with ecryptfs_msg_ctx_lists_mux
36 * held.
37 */
38static int ecryptfs_acquire_free_msg_ctx(struct ecryptfs_msg_ctx **msg_ctx)
39{
40 struct list_head *p;
41 int rc;
42
43 if (list_empty(&ecryptfs_msg_ctx_free_list)) {
44 printk(KERN_WARNING "%s: The eCryptfs free "
45 "context list is empty. It may be helpful to "
46 "specify the ecryptfs_message_buf_len "
47 "parameter to be greater than the current "
48 "value of [%d]\n", __func__, ecryptfs_message_buf_len);
49 rc = -ENOMEM;
50 goto out;
51 }
52 list_for_each(p, &ecryptfs_msg_ctx_free_list) {
53 *msg_ctx = list_entry(p, struct ecryptfs_msg_ctx, node);
54 if (mutex_trylock(&(*msg_ctx)->mux)) {
55 (*msg_ctx)->task = current;
56 rc = 0;
57 goto out;
58 }
59 }
60 rc = -ENOMEM;
61out:
62 return rc;
63}
64
65/**
66 * ecryptfs_msg_ctx_free_to_alloc
67 * @msg_ctx: The context to move from the free list to the alloc list
68 *
69 * Must be called with ecryptfs_msg_ctx_lists_mux held.
70 */
71static void ecryptfs_msg_ctx_free_to_alloc(struct ecryptfs_msg_ctx *msg_ctx)
72{
73 list_move(&msg_ctx->node, &ecryptfs_msg_ctx_alloc_list);
74 msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_PENDING;
75 msg_ctx->counter = ++ecryptfs_msg_counter;
76}
77
78/**
79 * ecryptfs_msg_ctx_alloc_to_free
80 * @msg_ctx: The context to move from the alloc list to the free list
81 *
82 * Must be called with ecryptfs_msg_ctx_lists_mux held.
83 */
84void ecryptfs_msg_ctx_alloc_to_free(struct ecryptfs_msg_ctx *msg_ctx)
85{
86 list_move(&(msg_ctx->node), &ecryptfs_msg_ctx_free_list);
87 kfree(msg_ctx->msg);
88 msg_ctx->msg = NULL;
89 msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_FREE;
90}
91
92/**
93 * ecryptfs_find_daemon_by_euid
94 * @daemon: If return value is zero, points to the desired daemon pointer
95 *
96 * Must be called with ecryptfs_daemon_hash_mux held.
97 *
98 * Search the hash list for the current effective user id.
99 *
100 * Returns zero if the user id exists in the list; non-zero otherwise.
101 */
102int ecryptfs_find_daemon_by_euid(struct ecryptfs_daemon **daemon)
103{
104 int rc;
105
106 hlist_for_each_entry(*daemon,
107 &ecryptfs_daemon_hash[ecryptfs_current_euid_hash()],
108 euid_chain) {
109 if (uid_eq((*daemon)->file->f_cred->euid, current_euid())) {
110 rc = 0;
111 goto out;
112 }
113 }
114 rc = -EINVAL;
115out:
116 return rc;
117}
118
119/**
120 * ecryptfs_spawn_daemon - Create and initialize a new daemon struct
121 * @daemon: Pointer to set to newly allocated daemon struct
122 * @file: File used when opening /dev/ecryptfs
123 *
124 * Must be called ceremoniously while in possession of
125 * ecryptfs_sacred_daemon_hash_mux
126 *
127 * Returns zero on success; non-zero otherwise
128 */
129int
130ecryptfs_spawn_daemon(struct ecryptfs_daemon **daemon, struct file *file)
131{
132 int rc = 0;
133
134 (*daemon) = kzalloc(sizeof(**daemon), GFP_KERNEL);
135 if (!(*daemon)) {
136 rc = -ENOMEM;
137 goto out;
138 }
139 (*daemon)->file = file;
140 mutex_init(&(*daemon)->mux);
141 INIT_LIST_HEAD(&(*daemon)->msg_ctx_out_queue);
142 init_waitqueue_head(&(*daemon)->wait);
143 (*daemon)->num_queued_msg_ctx = 0;
144 hlist_add_head(&(*daemon)->euid_chain,
145 &ecryptfs_daemon_hash[ecryptfs_current_euid_hash()]);
146out:
147 return rc;
148}
149
150/*
151 * ecryptfs_exorcise_daemon - Destroy the daemon struct
152 *
153 * Must be called ceremoniously while in possession of
154 * ecryptfs_daemon_hash_mux and the daemon's own mux.
155 */
156int ecryptfs_exorcise_daemon(struct ecryptfs_daemon *daemon)
157{
158 struct ecryptfs_msg_ctx *msg_ctx, *msg_ctx_tmp;
159 int rc = 0;
160
161 mutex_lock(&daemon->mux);
162 if ((daemon->flags & ECRYPTFS_DAEMON_IN_READ)
163 || (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)) {
164 rc = -EBUSY;
165 mutex_unlock(&daemon->mux);
166 goto out;
167 }
168 list_for_each_entry_safe(msg_ctx, msg_ctx_tmp,
169 &daemon->msg_ctx_out_queue, daemon_out_list) {
170 list_del(&msg_ctx->daemon_out_list);
171 daemon->num_queued_msg_ctx--;
172 printk(KERN_WARNING "%s: Warning: dropping message that is in "
173 "the out queue of a dying daemon\n", __func__);
174 ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
175 }
176 hlist_del(&daemon->euid_chain);
177 mutex_unlock(&daemon->mux);
178 kfree_sensitive(daemon);
179out:
180 return rc;
181}
182
183/**
184 * ecryptfs_process_response
185 * @daemon: eCryptfs daemon object
186 * @msg: The ecryptfs message received; the caller should sanity check
187 * msg->data_len and free the memory
188 * @seq: The sequence number of the message; must match the sequence
189 * number for the existing message context waiting for this
190 * response
191 *
192 * Processes a response message after sending an operation request to
193 * userspace. Some other process is awaiting this response. Before
194 * sending out its first communications, the other process allocated a
195 * msg_ctx from the ecryptfs_msg_ctx_arr at a particular index. The
196 * response message contains this index so that we can copy over the
197 * response message into the msg_ctx that the process holds a
198 * reference to. The other process is going to wake up, check to see
199 * that msg_ctx->state == ECRYPTFS_MSG_CTX_STATE_DONE, and then
200 * proceed to read off and process the response message. Returns zero
201 * upon delivery to desired context element; non-zero upon delivery
202 * failure or error.
203 *
204 * Returns zero on success; non-zero otherwise
205 */
206int ecryptfs_process_response(struct ecryptfs_daemon *daemon,
207 struct ecryptfs_message *msg, u32 seq)
208{
209 struct ecryptfs_msg_ctx *msg_ctx;
210 size_t msg_size;
211 int rc;
212
213 if (msg->index >= ecryptfs_message_buf_len) {
214 rc = -EINVAL;
215 printk(KERN_ERR "%s: Attempt to reference "
216 "context buffer at index [%d]; maximum "
217 "allowable is [%d]\n", __func__, msg->index,
218 (ecryptfs_message_buf_len - 1));
219 goto out;
220 }
221 msg_ctx = &ecryptfs_msg_ctx_arr[msg->index];
222 mutex_lock(&msg_ctx->mux);
223 if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_PENDING) {
224 rc = -EINVAL;
225 printk(KERN_WARNING "%s: Desired context element is not "
226 "pending a response\n", __func__);
227 goto unlock;
228 } else if (msg_ctx->counter != seq) {
229 rc = -EINVAL;
230 printk(KERN_WARNING "%s: Invalid message sequence; "
231 "expected [%d]; received [%d]\n", __func__,
232 msg_ctx->counter, seq);
233 goto unlock;
234 }
235 msg_size = (sizeof(*msg) + msg->data_len);
236 msg_ctx->msg = kmemdup(msg, msg_size, GFP_KERNEL);
237 if (!msg_ctx->msg) {
238 rc = -ENOMEM;
239 goto unlock;
240 }
241 msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_DONE;
242 wake_up_process(msg_ctx->task);
243 rc = 0;
244unlock:
245 mutex_unlock(&msg_ctx->mux);
246out:
247 return rc;
248}
249
250/**
251 * ecryptfs_send_message_locked
252 * @data: The data to send
253 * @data_len: The length of data
254 * @msg_type: Type of message
255 * @msg_ctx: The message context allocated for the send
256 *
257 * Must be called with ecryptfs_daemon_hash_mux held.
258 *
259 * Returns zero on success; non-zero otherwise
260 */
261static int
262ecryptfs_send_message_locked(char *data, int data_len, u8 msg_type,
263 struct ecryptfs_msg_ctx **msg_ctx)
264{
265 struct ecryptfs_daemon *daemon;
266 int rc;
267
268 rc = ecryptfs_find_daemon_by_euid(&daemon);
269 if (rc) {
270 rc = -ENOTCONN;
271 goto out;
272 }
273 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
274 rc = ecryptfs_acquire_free_msg_ctx(msg_ctx);
275 if (rc) {
276 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
277 printk(KERN_WARNING "%s: Could not claim a free "
278 "context element\n", __func__);
279 goto out;
280 }
281 ecryptfs_msg_ctx_free_to_alloc(*msg_ctx);
282 mutex_unlock(&(*msg_ctx)->mux);
283 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
284 rc = ecryptfs_send_miscdev(data, data_len, *msg_ctx, msg_type, 0,
285 daemon);
286 if (rc)
287 printk(KERN_ERR "%s: Error attempting to send message to "
288 "userspace daemon; rc = [%d]\n", __func__, rc);
289out:
290 return rc;
291}
292
293/**
294 * ecryptfs_send_message
295 * @data: The data to send
296 * @data_len: The length of data
297 * @msg_ctx: The message context allocated for the send
298 *
299 * Grabs ecryptfs_daemon_hash_mux.
300 *
301 * Returns zero on success; non-zero otherwise
302 */
303int ecryptfs_send_message(char *data, int data_len,
304 struct ecryptfs_msg_ctx **msg_ctx)
305{
306 int rc;
307
308 mutex_lock(&ecryptfs_daemon_hash_mux);
309 rc = ecryptfs_send_message_locked(data, data_len, ECRYPTFS_MSG_REQUEST,
310 msg_ctx);
311 mutex_unlock(&ecryptfs_daemon_hash_mux);
312 return rc;
313}
314
315/**
316 * ecryptfs_wait_for_response
317 * @msg_ctx: The context that was assigned when sending a message
318 * @msg: The incoming message from userspace; not set if rc != 0
319 *
320 * Sleeps until awaken by ecryptfs_receive_message or until the amount
321 * of time exceeds ecryptfs_message_wait_timeout. If zero is
322 * returned, msg will point to a valid message from userspace; a
323 * non-zero value is returned upon failure to receive a message or an
324 * error occurs. Callee must free @msg on success.
325 */
326int ecryptfs_wait_for_response(struct ecryptfs_msg_ctx *msg_ctx,
327 struct ecryptfs_message **msg)
328{
329 signed long timeout = ecryptfs_message_wait_timeout * HZ;
330 int rc = 0;
331
332sleep:
333 timeout = schedule_timeout_interruptible(timeout);
334 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
335 mutex_lock(&msg_ctx->mux);
336 if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_DONE) {
337 if (timeout) {
338 mutex_unlock(&msg_ctx->mux);
339 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
340 goto sleep;
341 }
342 rc = -ENOMSG;
343 } else {
344 *msg = msg_ctx->msg;
345 msg_ctx->msg = NULL;
346 }
347 ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
348 mutex_unlock(&msg_ctx->mux);
349 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
350 return rc;
351}
352
353int __init ecryptfs_init_messaging(void)
354{
355 int i;
356 int rc = 0;
357
358 if (ecryptfs_number_of_users > ECRYPTFS_MAX_NUM_USERS) {
359 ecryptfs_number_of_users = ECRYPTFS_MAX_NUM_USERS;
360 printk(KERN_WARNING "%s: Specified number of users is "
361 "too large, defaulting to [%d] users\n", __func__,
362 ecryptfs_number_of_users);
363 }
364 mutex_lock(&ecryptfs_daemon_hash_mux);
365 ecryptfs_hash_bits = 1;
366 while (ecryptfs_number_of_users >> ecryptfs_hash_bits)
367 ecryptfs_hash_bits++;
368 ecryptfs_daemon_hash = kmalloc((sizeof(struct hlist_head)
369 * (1 << ecryptfs_hash_bits)),
370 GFP_KERNEL);
371 if (!ecryptfs_daemon_hash) {
372 rc = -ENOMEM;
373 mutex_unlock(&ecryptfs_daemon_hash_mux);
374 goto out;
375 }
376 for (i = 0; i < (1 << ecryptfs_hash_bits); i++)
377 INIT_HLIST_HEAD(&ecryptfs_daemon_hash[i]);
378 mutex_unlock(&ecryptfs_daemon_hash_mux);
379 ecryptfs_msg_ctx_arr = kmalloc((sizeof(struct ecryptfs_msg_ctx)
380 * ecryptfs_message_buf_len),
381 GFP_KERNEL);
382 if (!ecryptfs_msg_ctx_arr) {
383 kfree(ecryptfs_daemon_hash);
384 rc = -ENOMEM;
385 goto out;
386 }
387 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
388 ecryptfs_msg_counter = 0;
389 for (i = 0; i < ecryptfs_message_buf_len; i++) {
390 INIT_LIST_HEAD(&ecryptfs_msg_ctx_arr[i].node);
391 INIT_LIST_HEAD(&ecryptfs_msg_ctx_arr[i].daemon_out_list);
392 mutex_init(&ecryptfs_msg_ctx_arr[i].mux);
393 mutex_lock(&ecryptfs_msg_ctx_arr[i].mux);
394 ecryptfs_msg_ctx_arr[i].index = i;
395 ecryptfs_msg_ctx_arr[i].state = ECRYPTFS_MSG_CTX_STATE_FREE;
396 ecryptfs_msg_ctx_arr[i].counter = 0;
397 ecryptfs_msg_ctx_arr[i].task = NULL;
398 ecryptfs_msg_ctx_arr[i].msg = NULL;
399 list_add_tail(&ecryptfs_msg_ctx_arr[i].node,
400 &ecryptfs_msg_ctx_free_list);
401 mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux);
402 }
403 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
404 rc = ecryptfs_init_ecryptfs_miscdev();
405 if (rc)
406 ecryptfs_release_messaging();
407out:
408 return rc;
409}
410
411void ecryptfs_release_messaging(void)
412{
413 if (ecryptfs_msg_ctx_arr) {
414 int i;
415
416 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
417 for (i = 0; i < ecryptfs_message_buf_len; i++) {
418 mutex_lock(&ecryptfs_msg_ctx_arr[i].mux);
419 kfree(ecryptfs_msg_ctx_arr[i].msg);
420 mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux);
421 }
422 kfree(ecryptfs_msg_ctx_arr);
423 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
424 }
425 if (ecryptfs_daemon_hash) {
426 struct ecryptfs_daemon *daemon;
427 struct hlist_node *n;
428 int i;
429
430 mutex_lock(&ecryptfs_daemon_hash_mux);
431 for (i = 0; i < (1 << ecryptfs_hash_bits); i++) {
432 int rc;
433
434 hlist_for_each_entry_safe(daemon, n,
435 &ecryptfs_daemon_hash[i],
436 euid_chain) {
437 rc = ecryptfs_exorcise_daemon(daemon);
438 if (rc)
439 printk(KERN_ERR "%s: Error whilst "
440 "attempting to destroy daemon; "
441 "rc = [%d]. Dazed and confused, "
442 "but trying to continue.\n",
443 __func__, rc);
444 }
445 }
446 kfree(ecryptfs_daemon_hash);
447 mutex_unlock(&ecryptfs_daemon_hash_mux);
448 }
449 ecryptfs_destroy_ecryptfs_miscdev();
450 return;
451}
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}