blob: bcb68c0cb1f0fed8ac5300c804b304879b08ae22 [file] [log] [blame]
Michael Halcrow88b4a072007-02-12 00:53:43 -08001/**
2 * eCryptfs: Linux filesystem encryption layer
3 *
Michael Halcrowf66e8832008-04-29 00:59:51 -07004 * Copyright (C) 2004-2008 International Business Machines Corp.
Michael Halcrow88b4a072007-02-12 00:53:43 -08005 * 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 */
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +040022#include <linux/sched.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090023#include <linux/slab.h>
Michael Halcrow6a3fd922008-04-29 00:59:52 -070024#include <linux/user_namespace.h>
25#include <linux/nsproxy.h>
Michael Halcrow88b4a072007-02-12 00:53:43 -080026#include "ecryptfs_kernel.h"
27
Michael Halcrowdd2a3b72007-02-12 00:53:46 -080028static LIST_HEAD(ecryptfs_msg_ctx_free_list);
29static LIST_HEAD(ecryptfs_msg_ctx_alloc_list);
30static struct mutex ecryptfs_msg_ctx_lists_mux;
Michael Halcrow88b4a072007-02-12 00:53:43 -080031
Michael Halcrowf66e8832008-04-29 00:59:51 -070032static struct hlist_head *ecryptfs_daemon_hash;
33struct mutex ecryptfs_daemon_hash_mux;
Andre Osterhuesa6f80fb2010-07-13 15:59:17 -050034static int ecryptfs_hash_bits;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -080035#define ecryptfs_uid_hash(uid) \
Andre Osterhuesa6f80fb2010-07-13 15:59:17 -050036 hash_long((unsigned long)uid, ecryptfs_hash_bits)
Michael Halcrow88b4a072007-02-12 00:53:43 -080037
Michael Halcrowf66e8832008-04-29 00:59:51 -070038static u32 ecryptfs_msg_counter;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -080039static struct ecryptfs_msg_ctx *ecryptfs_msg_ctx_arr;
Michael Halcrow88b4a072007-02-12 00:53:43 -080040
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
Michael Halcrowf66e8832008-04-29 00:59:51 -070046 * 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.
Michael Halcrow88b4a072007-02-12 00:53:43 -080050 */
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)) {
Michael Halcrowf66e8832008-04-29 00:59:51 -070057 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);
Michael Halcrow88b4a072007-02-12 00:53:43 -080062 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 *
Michael Halcrowf66e8832008-04-29 00:59:51 -070082 * Must be called with ecryptfs_msg_ctx_lists_mux held.
Michael Halcrow88b4a072007-02-12 00:53:43 -080083 */
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 *
Michael Halcrowf66e8832008-04-29 00:59:51 -070095 * Must be called with ecryptfs_msg_ctx_lists_mux held.
Michael Halcrow88b4a072007-02-12 00:53:43 -080096 */
Michael Halcrowf66e8832008-04-29 00:59:51 -070097void ecryptfs_msg_ctx_alloc_to_free(struct ecryptfs_msg_ctx *msg_ctx)
Michael Halcrow88b4a072007-02-12 00:53:43 -080098{
99 list_move(&(msg_ctx->node), &ecryptfs_msg_ctx_free_list);
100 if (msg_ctx->msg)
101 kfree(msg_ctx->msg);
Michael Halcrowf66e8832008-04-29 00:59:51 -0700102 msg_ctx->msg = NULL;
Michael Halcrow88b4a072007-02-12 00:53:43 -0800103 msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_FREE;
104}
105
106/**
Michael Halcrowf66e8832008-04-29 00:59:51 -0700107 * ecryptfs_find_daemon_by_euid
108 * @euid: The effective user id which maps to the desired daemon id
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700109 * @user_ns: The namespace in which @euid applies
Michael Halcrowf66e8832008-04-29 00:59:51 -0700110 * @daemon: If return value is zero, points to the desired daemon pointer
Michael Halcrow88b4a072007-02-12 00:53:43 -0800111 *
Michael Halcrowf66e8832008-04-29 00:59:51 -0700112 * 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.
Michael Halcrow88b4a072007-02-12 00:53:43 -0800117 */
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700118int ecryptfs_find_daemon_by_euid(struct ecryptfs_daemon **daemon, uid_t euid,
119 struct user_namespace *user_ns)
Michael Halcrow88b4a072007-02-12 00:53:43 -0800120{
121 struct hlist_node *elem;
122 int rc;
123
Michael Halcrowf66e8832008-04-29 00:59:51 -0700124 hlist_for_each_entry(*daemon, elem,
125 &ecryptfs_daemon_hash[ecryptfs_uid_hash(euid)],
126 euid_chain) {
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700127 if ((*daemon)->euid == euid && (*daemon)->user_ns == user_ns) {
Michael Halcrow88b4a072007-02-12 00:53:43 -0800128 rc = 0;
129 goto out;
130 }
131 }
132 rc = -EINVAL;
133out:
134 return rc;
135}
136
Michael Halcrowf66e8832008-04-29 00:59:51 -0700137/**
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
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700141 * @user_ns: The namespace in which @euid applies
Michael Halcrowf66e8832008-04-29 00:59:51 -0700142 * @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
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700150ecryptfs_spawn_daemon(struct ecryptfs_daemon **daemon, uid_t euid,
151 struct user_namespace *user_ns, struct pid *pid)
Michael Halcrowf66e8832008-04-29 00:59:51 -0700152{
153 int rc = 0;
154
155 (*daemon) = kzalloc(sizeof(**daemon), GFP_KERNEL);
156 if (!(*daemon)) {
157 rc = -ENOMEM;
Michael Halcrowdf261c52009-01-06 14:42:02 -0800158 printk(KERN_ERR "%s: Failed to allocate [%zd] bytes of "
Michael Halcrowf66e8832008-04-29 00:59:51 -0700159 "GFP_KERNEL memory\n", __func__, sizeof(**daemon));
160 goto out;
161 }
162 (*daemon)->euid = euid;
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700163 (*daemon)->user_ns = get_user_ns(user_ns);
164 (*daemon)->pid = get_pid(pid);
Michael Halcrowf66e8832008-04-29 00:59:51 -0700165 (*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:
Michael Halcrow88b4a072007-02-12 00:53:43 -0800173 return rc;
174}
175
176/**
Michael Halcrowf66e8832008-04-29 00:59:51 -0700177 * 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 "
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700192 "[0x%p], but it is in the midst of a read or a poll\n",
Michael Halcrowf66e8832008-04-29 00:59:51 -0700193 __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);
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700208 if (daemon->pid)
209 put_pid(daemon->pid);
210 if (daemon->user_ns)
211 put_user_ns(daemon->user_ns);
Michael Halcrowf66e8832008-04-29 00:59:51 -0700212 mutex_unlock(&daemon->mux);
Johannes Weiner00fcf2c2009-03-31 15:24:42 -0700213 kzfree(daemon);
Michael Halcrowf66e8832008-04-29 00:59:51 -0700214out:
Michael Halcrow88b4a072007-02-12 00:53:43 -0800215 return rc;
216}
217
218/**
219 * ecryptfs_process_quit
Michael Halcrowf66e8832008-04-29 00:59:51 -0700220 * @euid: The user ID owner of the message
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700221 * @user_ns: The namespace in which @euid applies
Michael Halcrow88b4a072007-02-12 00:53:43 -0800222 * @pid: The process ID for the userspace program that sent the
223 * message
224 *
Michael Halcrowf66e8832008-04-29 00:59:51 -0700225 * Deletes the corresponding daemon for the given euid and pid, if
Michael Halcrow88b4a072007-02-12 00:53:43 -0800226 * it is the registered that is requesting the deletion. Returns zero
Michael Halcrowf66e8832008-04-29 00:59:51 -0700227 * after deleting the desired daemon; non-zero otherwise.
Michael Halcrow88b4a072007-02-12 00:53:43 -0800228 */
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700229int ecryptfs_process_quit(uid_t euid, struct user_namespace *user_ns,
230 struct pid *pid)
Michael Halcrow88b4a072007-02-12 00:53:43 -0800231{
Michael Halcrowf66e8832008-04-29 00:59:51 -0700232 struct ecryptfs_daemon *daemon;
Michael Halcrow88b4a072007-02-12 00:53:43 -0800233 int rc;
234
Michael Halcrowf66e8832008-04-29 00:59:51 -0700235 mutex_lock(&ecryptfs_daemon_hash_mux);
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700236 rc = ecryptfs_find_daemon_by_euid(&daemon, euid, user_ns);
Michael Halcrowf66e8832008-04-29 00:59:51 -0700237 if (rc || !daemon) {
Michael Halcrow88b4a072007-02-12 00:53:43 -0800238 rc = -EINVAL;
Michael Halcrowf66e8832008-04-29 00:59:51 -0700239 printk(KERN_ERR "Received request from user [%d] to "
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700240 "unregister unrecognized daemon [0x%p]\n", euid, pid);
Michael Halcrowf66e8832008-04-29 00:59:51 -0700241 goto out_unlock;
Michael Halcrow88b4a072007-02-12 00:53:43 -0800242 }
Michael Halcrowf66e8832008-04-29 00:59:51 -0700243 rc = ecryptfs_exorcise_daemon(daemon);
244out_unlock:
245 mutex_unlock(&ecryptfs_daemon_hash_mux);
Michael Halcrow88b4a072007-02-12 00:53:43 -0800246 return rc;
247}
248
249/**
250 * ecryptfs_process_reponse
251 * @msg: The ecryptfs message received; the caller should sanity check
Michael Halcrowf66e8832008-04-29 00:59:51 -0700252 * msg->data_len and free the memory
Michael Halcrow88b4a072007-02-12 00:53:43 -0800253 * @pid: The process ID of the userspace application that sent the
254 * message
Michael Halcrowf66e8832008-04-29 00:59:51 -0700255 * @seq: The sequence number of the message; must match the sequence
256 * number for the existing message context waiting for this
257 * response
Michael Halcrow88b4a072007-02-12 00:53:43 -0800258 *
Michael Halcrowf66e8832008-04-29 00:59:51 -0700259 * 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
Michael Halcrow88b4a072007-02-12 00:53:43 -0800272 */
Michael Halcrowf66e8832008-04-29 00:59:51 -0700273int ecryptfs_process_response(struct ecryptfs_message *msg, uid_t euid,
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700274 struct user_namespace *user_ns, struct pid *pid,
275 u32 seq)
Michael Halcrow88b4a072007-02-12 00:53:43 -0800276{
Prarit Bhargavaa1275c32010-05-27 11:19:30 -0400277 struct ecryptfs_daemon *uninitialized_var(daemon);
Michael Halcrow88b4a072007-02-12 00:53:43 -0800278 struct ecryptfs_msg_ctx *msg_ctx;
Michael Halcrowf66e8832008-04-29 00:59:51 -0700279 size_t msg_size;
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700280 struct nsproxy *nsproxy;
Serge Hallyn18b6e042008-10-15 16:38:45 -0500281 struct user_namespace *tsk_user_ns;
David Howells4eea0352008-11-14 10:38:49 +1100282 uid_t ctx_euid;
Michael Halcrow88b4a072007-02-12 00:53:43 -0800283 int rc;
284
285 if (msg->index >= ecryptfs_message_buf_len) {
286 rc = -EINVAL;
Michael Halcrowf66e8832008-04-29 00:59:51 -0700287 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));
Michael Halcrow88b4a072007-02-12 00:53:43 -0800291 goto out;
292 }
293 msg_ctx = &ecryptfs_msg_ctx_arr[msg->index];
294 mutex_lock(&msg_ctx->mux);
Michael Halcrowf66e8832008-04-29 00:59:51 -0700295 mutex_lock(&ecryptfs_daemon_hash_mux);
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700296 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 }
Serge Hallyn18b6e042008-10-15 16:38:45 -0500306 tsk_user_ns = __task_cred(msg_ctx->task)->user->user_ns;
David Howells4eea0352008-11-14 10:38:49 +1100307 ctx_euid = task_euid(msg_ctx->task);
Serge Hallyn18b6e042008-10-15 16:38:45 -0500308 rc = ecryptfs_find_daemon_by_euid(&daemon, ctx_euid, tsk_user_ns);
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700309 rcu_read_unlock();
Michael Halcrowf66e8832008-04-29 00:59:51 -0700310 mutex_unlock(&ecryptfs_daemon_hash_mux);
311 if (rc) {
Michael Halcrow88b4a072007-02-12 00:53:43 -0800312 rc = -EBADMSG;
Michael Halcrowf66e8832008-04-29 00:59:51 -0700313 printk(KERN_WARNING "%s: User [%d] received a "
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700314 "message response from process [0x%p] but does "
Michael Halcrowf66e8832008-04-29 00:59:51 -0700315 "not have a registered daemon\n", __func__,
David Howells4eea0352008-11-14 10:38:49 +1100316 ctx_euid, pid);
Michael Halcrow88b4a072007-02-12 00:53:43 -0800317 goto wake_up;
318 }
David Howells4eea0352008-11-14 10:38:49 +1100319 if (ctx_euid != euid) {
Michael Halcrowdddfa462007-02-12 00:53:44 -0800320 rc = -EBADMSG;
Michael Halcrowf66e8832008-04-29 00:59:51 -0700321 printk(KERN_WARNING "%s: Received message from user "
322 "[%d]; expected message from user [%d]\n", __func__,
David Howells4eea0352008-11-14 10:38:49 +1100323 euid, ctx_euid);
Michael Halcrowdddfa462007-02-12 00:53:44 -0800324 goto unlock;
325 }
Serge Hallyn18b6e042008-10-15 16:38:45 -0500326 if (tsk_user_ns != user_ns) {
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700327 rc = -EBADMSG;
328 printk(KERN_WARNING "%s: Received message from user_ns "
329 "[0x%p]; expected message from user_ns [0x%p]\n",
Serge Hallyn18b6e042008-10-15 16:38:45 -0500330 __func__, user_ns, tsk_user_ns);
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700331 goto unlock;
332 }
Michael Halcrowf66e8832008-04-29 00:59:51 -0700333 if (daemon->pid != pid) {
Michael Halcrow88b4a072007-02-12 00:53:43 -0800334 rc = -EBADMSG;
Michael Halcrowf66e8832008-04-29 00:59:51 -0700335 printk(KERN_ERR "%s: User [%d] sent a message response "
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700336 "from an unrecognized process [0x%p]\n",
David Howells4eea0352008-11-14 10:38:49 +1100337 __func__, ctx_euid, pid);
Michael Halcrow88b4a072007-02-12 00:53:43 -0800338 goto unlock;
339 }
340 if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_PENDING) {
341 rc = -EINVAL;
Michael Halcrowf66e8832008-04-29 00:59:51 -0700342 printk(KERN_WARNING "%s: Desired context element is not "
343 "pending a response\n", __func__);
Michael Halcrow88b4a072007-02-12 00:53:43 -0800344 goto unlock;
345 } else if (msg_ctx->counter != seq) {
346 rc = -EINVAL;
Michael Halcrowf66e8832008-04-29 00:59:51 -0700347 printk(KERN_WARNING "%s: Invalid message sequence; "
348 "expected [%d]; received [%d]\n", __func__,
349 msg_ctx->counter, seq);
Michael Halcrow88b4a072007-02-12 00:53:43 -0800350 goto unlock;
351 }
Michael Halcrowf66e8832008-04-29 00:59:51 -0700352 msg_size = (sizeof(*msg) + msg->data_len);
Michael Halcrow88b4a072007-02-12 00:53:43 -0800353 msg_ctx->msg = kmalloc(msg_size, GFP_KERNEL);
354 if (!msg_ctx->msg) {
355 rc = -ENOMEM;
Michael Halcrowdf261c52009-01-06 14:42:02 -0800356 printk(KERN_ERR "%s: Failed to allocate [%zd] bytes of "
Michael Halcrowf66e8832008-04-29 00:59:51 -0700357 "GFP_KERNEL memory\n", __func__, msg_size);
Michael Halcrow88b4a072007-02-12 00:53:43 -0800358 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/**
Michael Halcrowf66e8832008-04-29 00:59:51 -0700372 * ecryptfs_send_message_locked
Michael Halcrow88b4a072007-02-12 00:53:43 -0800373 * @data: The data to send
374 * @data_len: The length of data
375 * @msg_ctx: The message context allocated for the send
Michael Halcrowf66e8832008-04-29 00:59:51 -0700376 *
377 * Must be called with ecryptfs_daemon_hash_mux held.
378 *
379 * Returns zero on success; non-zero otherwise
Michael Halcrow88b4a072007-02-12 00:53:43 -0800380 */
Michael Halcrowf66e8832008-04-29 00:59:51 -0700381static int
Tyler Hicks624ae522008-10-15 22:02:51 -0700382ecryptfs_send_message_locked(char *data, int data_len, u8 msg_type,
383 struct ecryptfs_msg_ctx **msg_ctx)
Michael Halcrow88b4a072007-02-12 00:53:43 -0800384{
Michael Halcrowf66e8832008-04-29 00:59:51 -0700385 struct ecryptfs_daemon *daemon;
David Howells4eea0352008-11-14 10:38:49 +1100386 uid_t euid = current_euid();
Michael Halcrow88b4a072007-02-12 00:53:43 -0800387 int rc;
388
Serge Hallyn18b6e042008-10-15 16:38:45 -0500389 rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
Michael Halcrowf66e8832008-04-29 00:59:51 -0700390 if (rc || !daemon) {
Michael Halcrow88b4a072007-02-12 00:53:43 -0800391 rc = -ENOTCONN;
Michael Halcrowf66e8832008-04-29 00:59:51 -0700392 printk(KERN_ERR "%s: User [%d] does not have a daemon "
David Howells4eea0352008-11-14 10:38:49 +1100393 "registered\n", __func__, euid);
Michael Halcrow88b4a072007-02-12 00:53:43 -0800394 goto out;
395 }
Michael Halcrow88b4a072007-02-12 00:53:43 -0800396 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);
Michael Halcrowf66e8832008-04-29 00:59:51 -0700400 printk(KERN_WARNING "%s: Could not claim a free "
401 "context element\n", __func__);
Michael Halcrow88b4a072007-02-12 00:53:43 -0800402 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);
Tyler Hicks624ae522008-10-15 22:02:51 -0700407 rc = ecryptfs_send_miscdev(data, data_len, *msg_ctx, msg_type, 0,
408 daemon);
Michael Halcrowf66e8832008-04-29 00:59:51 -0700409 if (rc)
410 printk(KERN_ERR "%s: Error attempting to send message to "
411 "userspace daemon; rc = [%d]\n", __func__, rc);
Michael Halcrow88b4a072007-02-12 00:53:43 -0800412out:
413 return rc;
414}
415
416/**
Michael Halcrowf66e8832008-04-29 00:59:51 -0700417 * ecryptfs_send_message
Michael Halcrowf66e8832008-04-29 00:59:51 -0700418 * @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 */
Tyler Hicks624ae522008-10-15 22:02:51 -0700426int ecryptfs_send_message(char *data, int data_len,
Michael Halcrowf66e8832008-04-29 00:59:51 -0700427 struct ecryptfs_msg_ctx **msg_ctx)
428{
429 int rc;
430
431 mutex_lock(&ecryptfs_daemon_hash_mux);
Tyler Hicks624ae522008-10-15 22:02:51 -0700432 rc = ecryptfs_send_message_locked(data, data_len, ECRYPTFS_MSG_REQUEST,
433 msg_ctx);
Michael Halcrowf66e8832008-04-29 00:59:51 -0700434 mutex_unlock(&ecryptfs_daemon_hash_mux);
435 return rc;
436}
437
438/**
Michael Halcrow88b4a072007-02-12 00:53:43 -0800439 * 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
Michael Halcrowf66e8832008-04-29 00:59:51 -0700447 * error occurs. Callee must free @msg on success.
Michael Halcrow88b4a072007-02-12 00:53:43 -0800448 */
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
Tyler Hicks624ae522008-10-15 22:02:51 -0700476int ecryptfs_init_messaging(void)
Michael Halcrow88b4a072007-02-12 00:53:43 -0800477{
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;
Michael Halcrowf66e8832008-04-29 00:59:51 -0700483 printk(KERN_WARNING "%s: Specified number of users is "
484 "too large, defaulting to [%d] users\n", __func__,
485 ecryptfs_number_of_users);
Michael Halcrow88b4a072007-02-12 00:53:43 -0800486 }
Michael Halcrowf66e8832008-04-29 00:59:51 -0700487 mutex_init(&ecryptfs_daemon_hash_mux);
488 mutex_lock(&ecryptfs_daemon_hash_mux);
Andre Osterhuesa6f80fb2010-07-13 15:59:17 -0500489 ecryptfs_hash_bits = 1;
490 while (ecryptfs_number_of_users >> ecryptfs_hash_bits)
491 ecryptfs_hash_bits++;
Michael Halcrowf66e8832008-04-29 00:59:51 -0700492 ecryptfs_daemon_hash = kmalloc((sizeof(struct hlist_head)
Andre Osterhuesa6f80fb2010-07-13 15:59:17 -0500493 * (1 << ecryptfs_hash_bits)),
494 GFP_KERNEL);
Michael Halcrowf66e8832008-04-29 00:59:51 -0700495 if (!ecryptfs_daemon_hash) {
Michael Halcrow88b4a072007-02-12 00:53:43 -0800496 rc = -ENOMEM;
Michael Halcrowf66e8832008-04-29 00:59:51 -0700497 printk(KERN_ERR "%s: Failed to allocate memory\n", __func__);
498 mutex_unlock(&ecryptfs_daemon_hash_mux);
Michael Halcrow88b4a072007-02-12 00:53:43 -0800499 goto out;
500 }
Andre Osterhuesa6f80fb2010-07-13 15:59:17 -0500501 for (i = 0; i < (1 << ecryptfs_hash_bits); i++)
Michael Halcrowf66e8832008-04-29 00:59:51 -0700502 INIT_HLIST_HEAD(&ecryptfs_daemon_hash[i]);
503 mutex_unlock(&ecryptfs_daemon_hash_mux);
Michael Halcrow88b4a072007-02-12 00:53:43 -0800504 ecryptfs_msg_ctx_arr = kmalloc((sizeof(struct ecryptfs_msg_ctx)
Michael Halcrowf66e8832008-04-29 00:59:51 -0700505 * ecryptfs_message_buf_len),
506 GFP_KERNEL);
Michael Halcrow88b4a072007-02-12 00:53:43 -0800507 if (!ecryptfs_msg_ctx_arr) {
508 rc = -ENOMEM;
Michael Halcrowf66e8832008-04-29 00:59:51 -0700509 printk(KERN_ERR "%s: Failed to allocate memory\n", __func__);
Michael Halcrow88b4a072007-02-12 00:53:43 -0800510 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);
Michael Halcrowf66e8832008-04-29 00:59:51 -0700517 INIT_LIST_HEAD(&ecryptfs_msg_ctx_arr[i].daemon_out_list);
Michael Halcrow88b4a072007-02-12 00:53:43 -0800518 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);
Tyler Hicks624ae522008-10-15 22:02:51 -0700530 rc = ecryptfs_init_ecryptfs_miscdev();
531 if (rc)
532 ecryptfs_release_messaging();
Michael Halcrow88b4a072007-02-12 00:53:43 -0800533out:
534 return rc;
535}
536
Tyler Hicks624ae522008-10-15 22:02:51 -0700537void ecryptfs_release_messaging(void)
Michael Halcrow88b4a072007-02-12 00:53:43 -0800538{
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 }
Michael Halcrowf66e8832008-04-29 00:59:51 -0700552 if (ecryptfs_daemon_hash) {
Michael Halcrow88b4a072007-02-12 00:53:43 -0800553 struct hlist_node *elem;
Michael Halcrowf66e8832008-04-29 00:59:51 -0700554 struct ecryptfs_daemon *daemon;
Michael Halcrow88b4a072007-02-12 00:53:43 -0800555 int i;
556
Michael Halcrowf66e8832008-04-29 00:59:51 -0700557 mutex_lock(&ecryptfs_daemon_hash_mux);
Andre Osterhuesa6f80fb2010-07-13 15:59:17 -0500558 for (i = 0; i < (1 << ecryptfs_hash_bits); i++) {
Michael Halcrowf66e8832008-04-29 00:59:51 -0700559 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);
Michael Halcrow88b4a072007-02-12 00:53:43 -0800571 }
572 }
Michael Halcrowf66e8832008-04-29 00:59:51 -0700573 kfree(ecryptfs_daemon_hash);
574 mutex_unlock(&ecryptfs_daemon_hash_mux);
Michael Halcrow88b4a072007-02-12 00:53:43 -0800575 }
Tyler Hicks624ae522008-10-15 22:02:51 -0700576 ecryptfs_destroy_ecryptfs_miscdev();
Michael Halcrow88b4a072007-02-12 00:53:43 -0800577 return;
578}