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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_uid_hash(uid) \
36 hash_long((unsigned long)uid, 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 if (msg_ctx->msg)
101 kfree(msg_ctx->msg);
102 msg_ctx->msg = NULL;
103 msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_FREE;
104}
105
106/**
107 * ecryptfs_find_daemon_by_euid
108 * @euid: The effective user id which maps to the desired daemon id
109 * @user_ns: The namespace in which @euid applies
110 * @daemon: If return value is zero, points to the desired daemon pointer
111 *
112 * Must be called with ecryptfs_daemon_hash_mux held.
113 *
114 * Search the hash list for the given user id.
115 *
116 * Returns zero if the user id exists in the list; non-zero otherwise.
117 */
118int ecryptfs_find_daemon_by_euid(struct ecryptfs_daemon **daemon, uid_t euid,
119 struct user_namespace *user_ns)
120{
121 struct hlist_node *elem;
122 int rc;
123
124 hlist_for_each_entry(*daemon, elem,
125 &ecryptfs_daemon_hash[ecryptfs_uid_hash(euid)],
126 euid_chain) {
127 if ((*daemon)->euid == euid && (*daemon)->user_ns == user_ns) {
128 rc = 0;
129 goto out;
130 }
131 }
132 rc = -EINVAL;
133out:
134 return rc;
135}
136
137/**
138 * ecryptfs_spawn_daemon - Create and initialize a new daemon struct
139 * @daemon: Pointer to set to newly allocated daemon struct
140 * @euid: Effective user id for the daemon
141 * @user_ns: The namespace in which @euid applies
142 * @pid: Process id for the daemon
143 *
144 * Must be called ceremoniously while in possession of
145 * ecryptfs_sacred_daemon_hash_mux
146 *
147 * Returns zero on success; non-zero otherwise
148 */
149int
150ecryptfs_spawn_daemon(struct ecryptfs_daemon **daemon, uid_t euid,
151 struct user_namespace *user_ns, struct pid *pid)
152{
153 int rc = 0;
154
155 (*daemon) = kzalloc(sizeof(**daemon), GFP_KERNEL);
156 if (!(*daemon)) {
157 rc = -ENOMEM;
158 printk(KERN_ERR "%s: Failed to allocate [%zd] bytes of "
159 "GFP_KERNEL memory\n", __func__, sizeof(**daemon));
160 goto out;
161 }
162 (*daemon)->euid = euid;
163 (*daemon)->user_ns = get_user_ns(user_ns);
164 (*daemon)->pid = get_pid(pid);
165 (*daemon)->task = current;
166 mutex_init(&(*daemon)->mux);
167 INIT_LIST_HEAD(&(*daemon)->msg_ctx_out_queue);
168 init_waitqueue_head(&(*daemon)->wait);
169 (*daemon)->num_queued_msg_ctx = 0;
170 hlist_add_head(&(*daemon)->euid_chain,
171 &ecryptfs_daemon_hash[ecryptfs_uid_hash(euid)]);
172out:
173 return rc;
174}
175
176/**
177 * ecryptfs_exorcise_daemon - Destroy the daemon struct
178 *
179 * Must be called ceremoniously while in possession of
180 * ecryptfs_daemon_hash_mux and the daemon's own mux.
181 */
182int ecryptfs_exorcise_daemon(struct ecryptfs_daemon *daemon)
183{
184 struct ecryptfs_msg_ctx *msg_ctx, *msg_ctx_tmp;
185 int rc = 0;
186
187 mutex_lock(&daemon->mux);
188 if ((daemon->flags & ECRYPTFS_DAEMON_IN_READ)
189 || (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)) {
190 rc = -EBUSY;
191 printk(KERN_WARNING "%s: Attempt to destroy daemon with pid "
192 "[0x%p], but it is in the midst of a read or a poll\n",
193 __func__, daemon->pid);
194 mutex_unlock(&daemon->mux);
195 goto out;
196 }
197 list_for_each_entry_safe(msg_ctx, msg_ctx_tmp,
198 &daemon->msg_ctx_out_queue, daemon_out_list) {
199 list_del(&msg_ctx->daemon_out_list);
200 daemon->num_queued_msg_ctx--;
201 printk(KERN_WARNING "%s: Warning: dropping message that is in "
202 "the out queue of a dying daemon\n", __func__);
203 ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
204 }
205 hlist_del(&daemon->euid_chain);
206 if (daemon->task)
207 wake_up_process(daemon->task);
208 if (daemon->pid)
209 put_pid(daemon->pid);
210 if (daemon->user_ns)
211 put_user_ns(daemon->user_ns);
212 mutex_unlock(&daemon->mux);
213 kzfree(daemon);
214out:
215 return rc;
216}
217
218/**
219 * ecryptfs_process_quit
220 * @euid: The user ID owner of the message
221 * @user_ns: The namespace in which @euid applies
222 * @pid: The process ID for the userspace program that sent the
223 * message
224 *
225 * Deletes the corresponding daemon for the given euid and pid, if
226 * it is the registered that is requesting the deletion. Returns zero
227 * after deleting the desired daemon; non-zero otherwise.
228 */
229int ecryptfs_process_quit(uid_t euid, struct user_namespace *user_ns,
230 struct pid *pid)
231{
232 struct ecryptfs_daemon *daemon;
233 int rc;
234
235 mutex_lock(&ecryptfs_daemon_hash_mux);
236 rc = ecryptfs_find_daemon_by_euid(&daemon, euid, user_ns);
237 if (rc || !daemon) {
238 rc = -EINVAL;
239 printk(KERN_ERR "Received request from user [%d] to "
240 "unregister unrecognized daemon [0x%p]\n", euid, pid);
241 goto out_unlock;
242 }
243 rc = ecryptfs_exorcise_daemon(daemon);
244out_unlock:
245 mutex_unlock(&ecryptfs_daemon_hash_mux);
246 return rc;
247}
248
249/**
250 * ecryptfs_process_reponse
251 * @msg: The ecryptfs message received; the caller should sanity check
252 * msg->data_len and free the memory
253 * @pid: The process ID of the userspace application that sent the
254 * message
255 * @seq: The sequence number of the message; must match the sequence
256 * number for the existing message context waiting for this
257 * response
258 *
259 * Processes a response message after sending an operation request to
260 * userspace. Some other process is awaiting this response. Before
261 * sending out its first communications, the other process allocated a
262 * msg_ctx from the ecryptfs_msg_ctx_arr at a particular index. The
263 * response message contains this index so that we can copy over the
264 * response message into the msg_ctx that the process holds a
265 * reference to. The other process is going to wake up, check to see
266 * that msg_ctx->state == ECRYPTFS_MSG_CTX_STATE_DONE, and then
267 * proceed to read off and process the response message. Returns zero
268 * upon delivery to desired context element; non-zero upon delivery
269 * failure or error.
270 *
271 * Returns zero on success; non-zero otherwise
272 */
273int ecryptfs_process_response(struct ecryptfs_message *msg, uid_t euid,
274 struct user_namespace *user_ns, struct pid *pid,
275 u32 seq)
276{
277 struct ecryptfs_daemon *uninitialized_var(daemon);
278 struct ecryptfs_msg_ctx *msg_ctx;
279 size_t msg_size;
280 struct nsproxy *nsproxy;
281 struct user_namespace *tsk_user_ns;
282 uid_t ctx_euid;
283 int rc;
284
285 if (msg->index >= ecryptfs_message_buf_len) {
286 rc = -EINVAL;
287 printk(KERN_ERR "%s: Attempt to reference "
288 "context buffer at index [%d]; maximum "
289 "allowable is [%d]\n", __func__, msg->index,
290 (ecryptfs_message_buf_len - 1));
291 goto out;
292 }
293 msg_ctx = &ecryptfs_msg_ctx_arr[msg->index];
294 mutex_lock(&msg_ctx->mux);
295 mutex_lock(&ecryptfs_daemon_hash_mux);
296 rcu_read_lock();
297 nsproxy = task_nsproxy(msg_ctx->task);
298 if (nsproxy == NULL) {
299 rc = -EBADMSG;
300 printk(KERN_ERR "%s: Receiving process is a zombie. Dropping "
301 "message.\n", __func__);
302 rcu_read_unlock();
303 mutex_unlock(&ecryptfs_daemon_hash_mux);
304 goto wake_up;
305 }
306 tsk_user_ns = __task_cred(msg_ctx->task)->user->user_ns;
307 ctx_euid = task_euid(msg_ctx->task);
308 rc = ecryptfs_find_daemon_by_euid(&daemon, ctx_euid, tsk_user_ns);
309 rcu_read_unlock();
310 mutex_unlock(&ecryptfs_daemon_hash_mux);
311 if (rc) {
312 rc = -EBADMSG;
313 printk(KERN_WARNING "%s: User [%d] received a "
314 "message response from process [0x%p] but does "
315 "not have a registered daemon\n", __func__,
316 ctx_euid, pid);
317 goto wake_up;
318 }
319 if (ctx_euid != euid) {
320 rc = -EBADMSG;
321 printk(KERN_WARNING "%s: Received message from user "
322 "[%d]; expected message from user [%d]\n", __func__,
323 euid, ctx_euid);
324 goto unlock;
325 }
326 if (tsk_user_ns != user_ns) {
327 rc = -EBADMSG;
328 printk(KERN_WARNING "%s: Received message from user_ns "
329 "[0x%p]; expected message from user_ns [0x%p]\n",
330 __func__, user_ns, tsk_user_ns);
331 goto unlock;
332 }
333 if (daemon->pid != pid) {
334 rc = -EBADMSG;
335 printk(KERN_ERR "%s: User [%d] sent a message response "
336 "from an unrecognized process [0x%p]\n",
337 __func__, ctx_euid, pid);
338 goto unlock;
339 }
340 if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_PENDING) {
341 rc = -EINVAL;
342 printk(KERN_WARNING "%s: Desired context element is not "
343 "pending a response\n", __func__);
344 goto unlock;
345 } else if (msg_ctx->counter != seq) {
346 rc = -EINVAL;
347 printk(KERN_WARNING "%s: Invalid message sequence; "
348 "expected [%d]; received [%d]\n", __func__,
349 msg_ctx->counter, seq);
350 goto unlock;
351 }
352 msg_size = (sizeof(*msg) + msg->data_len);
353 msg_ctx->msg = kmalloc(msg_size, GFP_KERNEL);
354 if (!msg_ctx->msg) {
355 rc = -ENOMEM;
356 printk(KERN_ERR "%s: Failed to allocate [%zd] bytes of "
357 "GFP_KERNEL memory\n", __func__, msg_size);
358 goto unlock;
359 }
360 memcpy(msg_ctx->msg, msg, msg_size);
361 msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_DONE;
362 rc = 0;
363wake_up:
364 wake_up_process(msg_ctx->task);
365unlock:
366 mutex_unlock(&msg_ctx->mux);
367out:
368 return rc;
369}
370
371/**
372 * ecryptfs_send_message_locked
373 * @data: The data to send
374 * @data_len: The length of data
375 * @msg_ctx: The message context allocated for the send
376 *
377 * Must be called with ecryptfs_daemon_hash_mux held.
378 *
379 * Returns zero on success; non-zero otherwise
380 */
381static int
382ecryptfs_send_message_locked(char *data, int data_len, u8 msg_type,
383 struct ecryptfs_msg_ctx **msg_ctx)
384{
385 struct ecryptfs_daemon *daemon;
386 uid_t euid = current_euid();
387 int rc;
388
389 rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
390 if (rc || !daemon) {
391 rc = -ENOTCONN;
392 printk(KERN_ERR "%s: User [%d] does not have a daemon "
393 "registered\n", __func__, euid);
394 goto out;
395 }
396 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
397 rc = ecryptfs_acquire_free_msg_ctx(msg_ctx);
398 if (rc) {
399 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
400 printk(KERN_WARNING "%s: Could not claim a free "
401 "context element\n", __func__);
402 goto out;
403 }
404 ecryptfs_msg_ctx_free_to_alloc(*msg_ctx);
405 mutex_unlock(&(*msg_ctx)->mux);
406 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
407 rc = ecryptfs_send_miscdev(data, data_len, *msg_ctx, msg_type, 0,
408 daemon);
409 if (rc)
410 printk(KERN_ERR "%s: Error attempting to send message to "
411 "userspace daemon; rc = [%d]\n", __func__, rc);
412out:
413 return rc;
414}
415
416/**
417 * ecryptfs_send_message
418 * @data: The data to send
419 * @data_len: The length of data
420 * @msg_ctx: The message context allocated for the send
421 *
422 * Grabs ecryptfs_daemon_hash_mux.
423 *
424 * Returns zero on success; non-zero otherwise
425 */
426int ecryptfs_send_message(char *data, int data_len,
427 struct ecryptfs_msg_ctx **msg_ctx)
428{
429 int rc;
430
431 mutex_lock(&ecryptfs_daemon_hash_mux);
432 rc = ecryptfs_send_message_locked(data, data_len, ECRYPTFS_MSG_REQUEST,
433 msg_ctx);
434 mutex_unlock(&ecryptfs_daemon_hash_mux);
435 return rc;
436}
437
438/**
439 * ecryptfs_wait_for_response
440 * @msg_ctx: The context that was assigned when sending a message
441 * @msg: The incoming message from userspace; not set if rc != 0
442 *
443 * Sleeps until awaken by ecryptfs_receive_message or until the amount
444 * of time exceeds ecryptfs_message_wait_timeout. If zero is
445 * returned, msg will point to a valid message from userspace; a
446 * non-zero value is returned upon failure to receive a message or an
447 * error occurs. Callee must free @msg on success.
448 */
449int ecryptfs_wait_for_response(struct ecryptfs_msg_ctx *msg_ctx,
450 struct ecryptfs_message **msg)
451{
452 signed long timeout = ecryptfs_message_wait_timeout * HZ;
453 int rc = 0;
454
455sleep:
456 timeout = schedule_timeout_interruptible(timeout);
457 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
458 mutex_lock(&msg_ctx->mux);
459 if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_DONE) {
460 if (timeout) {
461 mutex_unlock(&msg_ctx->mux);
462 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
463 goto sleep;
464 }
465 rc = -ENOMSG;
466 } else {
467 *msg = msg_ctx->msg;
468 msg_ctx->msg = NULL;
469 }
470 ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
471 mutex_unlock(&msg_ctx->mux);
472 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
473 return rc;
474}
475
476int __init ecryptfs_init_messaging(void)
477{
478 int i;
479 int rc = 0;
480
481 if (ecryptfs_number_of_users > ECRYPTFS_MAX_NUM_USERS) {
482 ecryptfs_number_of_users = ECRYPTFS_MAX_NUM_USERS;
483 printk(KERN_WARNING "%s: Specified number of users is "
484 "too large, defaulting to [%d] users\n", __func__,
485 ecryptfs_number_of_users);
486 }
487 mutex_init(&ecryptfs_daemon_hash_mux);
488 mutex_lock(&ecryptfs_daemon_hash_mux);
489 ecryptfs_hash_bits = 1;
490 while (ecryptfs_number_of_users >> ecryptfs_hash_bits)
491 ecryptfs_hash_bits++;
492 ecryptfs_daemon_hash = kmalloc((sizeof(struct hlist_head)
493 * (1 << ecryptfs_hash_bits)),
494 GFP_KERNEL);
495 if (!ecryptfs_daemon_hash) {
496 rc = -ENOMEM;
497 printk(KERN_ERR "%s: Failed to allocate memory\n", __func__);
498 mutex_unlock(&ecryptfs_daemon_hash_mux);
499 goto out;
500 }
501 for (i = 0; i < (1 << ecryptfs_hash_bits); i++)
502 INIT_HLIST_HEAD(&ecryptfs_daemon_hash[i]);
503 mutex_unlock(&ecryptfs_daemon_hash_mux);
504 ecryptfs_msg_ctx_arr = kmalloc((sizeof(struct ecryptfs_msg_ctx)
505 * ecryptfs_message_buf_len),
506 GFP_KERNEL);
507 if (!ecryptfs_msg_ctx_arr) {
508 rc = -ENOMEM;
509 printk(KERN_ERR "%s: Failed to allocate memory\n", __func__);
510 goto out;
511 }
512 mutex_init(&ecryptfs_msg_ctx_lists_mux);
513 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
514 ecryptfs_msg_counter = 0;
515 for (i = 0; i < ecryptfs_message_buf_len; i++) {
516 INIT_LIST_HEAD(&ecryptfs_msg_ctx_arr[i].node);
517 INIT_LIST_HEAD(&ecryptfs_msg_ctx_arr[i].daemon_out_list);
518 mutex_init(&ecryptfs_msg_ctx_arr[i].mux);
519 mutex_lock(&ecryptfs_msg_ctx_arr[i].mux);
520 ecryptfs_msg_ctx_arr[i].index = i;
521 ecryptfs_msg_ctx_arr[i].state = ECRYPTFS_MSG_CTX_STATE_FREE;
522 ecryptfs_msg_ctx_arr[i].counter = 0;
523 ecryptfs_msg_ctx_arr[i].task = NULL;
524 ecryptfs_msg_ctx_arr[i].msg = NULL;
525 list_add_tail(&ecryptfs_msg_ctx_arr[i].node,
526 &ecryptfs_msg_ctx_free_list);
527 mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux);
528 }
529 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
530 rc = ecryptfs_init_ecryptfs_miscdev();
531 if (rc)
532 ecryptfs_release_messaging();
533out:
534 return rc;
535}
536
537void ecryptfs_release_messaging(void)
538{
539 if (ecryptfs_msg_ctx_arr) {
540 int i;
541
542 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
543 for (i = 0; i < ecryptfs_message_buf_len; i++) {
544 mutex_lock(&ecryptfs_msg_ctx_arr[i].mux);
545 if (ecryptfs_msg_ctx_arr[i].msg)
546 kfree(ecryptfs_msg_ctx_arr[i].msg);
547 mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux);
548 }
549 kfree(ecryptfs_msg_ctx_arr);
550 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
551 }
552 if (ecryptfs_daemon_hash) {
553 struct hlist_node *elem;
554 struct ecryptfs_daemon *daemon;
555 int i;
556
557 mutex_lock(&ecryptfs_daemon_hash_mux);
558 for (i = 0; i < (1 << ecryptfs_hash_bits); i++) {
559 int rc;
560
561 hlist_for_each_entry(daemon, elem,
562 &ecryptfs_daemon_hash[i],
563 euid_chain) {
564 rc = ecryptfs_exorcise_daemon(daemon);
565 if (rc)
566 printk(KERN_ERR "%s: Error whilst "
567 "attempting to destroy daemon; "
568 "rc = [%d]. Dazed and confused, "
569 "but trying to continue.\n",
570 __func__, rc);
571 }
572 }
573 kfree(ecryptfs_daemon_hash);
574 mutex_unlock(&ecryptfs_daemon_hash_mux);
575 }
576 ecryptfs_destroy_ecryptfs_miscdev();
577 return;
578}