fs/ecryptfs/messaging.c

   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/user_namespace.h>
  24 #include <linux/nsproxy.h>
  25 #include "ecryptfs_kernel.h"
  26
  27 static LIST_HEAD(ecryptfs_msg_ctx_free_list);
  28 static LIST_HEAD(ecryptfs_msg_ctx_alloc_list);
  29 static struct mutex ecryptfs_msg_ctx_lists_mux;
  30
  31 static struct hlist_head *ecryptfs_daemon_hash;
  32 struct mutex ecryptfs_daemon_hash_mux;
  33 static int ecryptfs_hash_buckets;
  34 #define ecryptfs_uid_hash(uid) \
  35         hash_long((unsigned long)uid, ecryptfs_hash_buckets)
  36
  37 static u32 ecryptfs_msg_counter;
  38 static struct ecryptfs_msg_ctx *ecryptfs_msg_ctx_arr;
  39
  40 /**
  41  * ecryptfs_acquire_free_msg_ctx
  42  * @msg_ctx: The context that was acquired from the free list
  43  *
  44  * Acquires a context element from the free list and locks the mutex
  45  * on the context.  Sets the msg_ctx task to current.  Returns zero on
  46  * success; non-zero on error or upon failure to acquire a free
  47  * context element.  Must be called with ecryptfs_msg_ctx_lists_mux
  48  * held.
  49  */
  50 static int ecryptfs_acquire_free_msg_ctx(struct ecryptfs_msg_ctx **msg_ctx)
  51 {
  52         struct list_head *p;
  53         int rc;
  54
  55         if (list_empty(&ecryptfs_msg_ctx_free_list)) {
  56                 printk(KERN_WARNING "%s: The eCryptfs free "
  57                        "context list is empty.  It may be helpful to "
  58                        "specify the ecryptfs_message_buf_len "
  59                        "parameter to be greater than the current "
  60                        "value of [%d]\n", __func__, ecryptfs_message_buf_len);
  61                 rc = -ENOMEM;
  62                 goto out;
  63         }
  64         list_for_each(p, &ecryptfs_msg_ctx_free_list) {
  65                 *msg_ctx = list_entry(p, struct ecryptfs_msg_ctx, node);
  66                 if (mutex_trylock(&(*msg_ctx)->mux)) {
  67                         (*msg_ctx)->task = current;
  68                         rc = 0;
  69                         goto out;
  70                 }
  71         }
  72         rc = -ENOMEM;
  73 out:
  74         return rc;
  75 }
  76
  77 /**
  78  * ecryptfs_msg_ctx_free_to_alloc
  79  * @msg_ctx: The context to move from the free list to the alloc list
  80  *
  81  * Must be called with ecryptfs_msg_ctx_lists_mux held.
  82  */
  83 static void ecryptfs_msg_ctx_free_to_alloc(struct ecryptfs_msg_ctx *msg_ctx)
  84 {
  85         list_move(&msg_ctx->node, &ecryptfs_msg_ctx_alloc_list);
  86         msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_PENDING;
  87         msg_ctx->counter = ++ecryptfs_msg_counter;
  88 }
  89
  90 /**
  91  * ecryptfs_msg_ctx_alloc_to_free
  92  * @msg_ctx: The context to move from the alloc list to the free list
  93  *
  94  * Must be called with ecryptfs_msg_ctx_lists_mux held.
  95  */
  96 void ecryptfs_msg_ctx_alloc_to_free(struct ecryptfs_msg_ctx *msg_ctx)
  97 {
  98         list_move(&(msg_ctx->node), &ecryptfs_msg_ctx_free_list);
  99         if (msg_ctx->msg)
 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  * @euid: The effective user id which maps to the desired daemon id
 108  * @user_ns: The namespace in which @euid applies
 109  * @daemon: If return value is zero, points to the desired daemon pointer
 110  *
 111  * Must be called with ecryptfs_daemon_hash_mux held.
 112  *
 113  * Search the hash list for the given user id.
 114  *
 115  * Returns zero if the user id exists in the list; non-zero otherwise.
 116  */
 117 int ecryptfs_find_daemon_by_euid(struct ecryptfs_daemon **daemon, uid_t euid,
 118                                  struct user_namespace *user_ns)
 119 {
 120         struct hlist_node *elem;
 121         int rc;
 122
 123         hlist_for_each_entry(*daemon, elem,
 124                              &ecryptfs_daemon_hash[ecryptfs_uid_hash(euid)],
 125                              euid_chain) {
 126                 if ((*daemon)->euid == euid && (*daemon)->user_ns == user_ns) {
 127                         rc = 0;
 128                         goto out;
 129                 }
 130         }
 131         rc = -EINVAL;
 132 out:
 133         return rc;
 134 }
 135
 136 static int
 137 ecryptfs_send_message_locked(char *data, int data_len, u8 msg_type,
 138                              struct ecryptfs_msg_ctx **msg_ctx);
 139
 140 /**
 141  * ecryptfs_send_raw_message
 142  * @msg_type: Message type
 143  * @daemon: Daemon struct for recipient of message
 144  *
 145  * A raw message is one that does not include an ecryptfs_message
 146  * struct. It simply has a type.
 147  *
 148  * Must be called with ecryptfs_daemon_hash_mux held.
 149  *
 150  * Returns zero on success; non-zero otherwise
 151  */
 152 static int ecryptfs_send_raw_message(u8 msg_type,
 153                                      struct ecryptfs_daemon *daemon)
 154 {
 155         struct ecryptfs_msg_ctx *msg_ctx;
 156         int rc;
 157
 158         rc = ecryptfs_send_message_locked(NULL, 0, msg_type, &msg_ctx);
 159         if (rc) {
 160                 printk(KERN_ERR "%s: Error whilst attempting to send "
 161                        "message to ecryptfsd; rc = [%d]\n", __func__, rc);
 162                 goto out;
 163         }
 164         /* Raw messages are logically context-free (e.g., no
 165          * reply is expected), so we set the state of the
 166          * ecryptfs_msg_ctx object to indicate that it should
 167          * be freed as soon as the message is sent. */
 168         mutex_lock(&msg_ctx->mux);
 169         msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_NO_REPLY;
 170         mutex_unlock(&msg_ctx->mux);
 171 out:
 172         return rc;
 173 }
 174
 175 /**
 176  * ecryptfs_spawn_daemon - Create and initialize a new daemon struct
 177  * @daemon: Pointer to set to newly allocated daemon struct
 178  * @euid: Effective user id for the daemon
 179  * @user_ns: The namespace in which @euid applies
 180  * @pid: Process id for the daemon
 181  *
 182  * Must be called ceremoniously while in possession of
 183  * ecryptfs_sacred_daemon_hash_mux
 184  *
 185  * Returns zero on success; non-zero otherwise
 186  */
 187 int
 188 ecryptfs_spawn_daemon(struct ecryptfs_daemon **daemon, uid_t euid,
 189                       struct user_namespace *user_ns, struct pid *pid)
 190 {
 191         int rc = 0;
 192
 193         (*daemon) = kzalloc(sizeof(**daemon), GFP_KERNEL);
 194         if (!(*daemon)) {
 195                 rc = -ENOMEM;
 196                 printk(KERN_ERR "%s: Failed to allocate [%zd] bytes of "
 197                        "GFP_KERNEL memory\n", __func__, sizeof(**daemon));
 198                 goto out;
 199         }
 200         (*daemon)->euid = euid;
 201         (*daemon)->user_ns = get_user_ns(user_ns);
 202         (*daemon)->pid = get_pid(pid);
 203         (*daemon)->task = current;
 204         mutex_init(&(*daemon)->mux);
 205         INIT_LIST_HEAD(&(*daemon)->msg_ctx_out_queue);
 206         init_waitqueue_head(&(*daemon)->wait);
 207         (*daemon)->num_queued_msg_ctx = 0;
 208         hlist_add_head(&(*daemon)->euid_chain,
 209                        &ecryptfs_daemon_hash[ecryptfs_uid_hash(euid)]);
 210 out:
 211         return rc;
 212 }
 213
 214 /**
 215  * ecryptfs_process_helo
 216  * @euid: The user ID owner of the message
 217  * @user_ns: The namespace in which @euid applies
 218  * @pid: The process ID for the userspace program that sent the
 219  *       message
 220  *
 221  * Adds the euid and pid values to the daemon euid hash.  If an euid
 222  * already has a daemon pid registered, the daemon will be
 223  * unregistered before the new daemon is put into the hash list.
 224  * Returns zero after adding a new daemon to the hash list;
 225  * non-zero otherwise.
 226  */
 227 int ecryptfs_process_helo(uid_t euid, struct user_namespace *user_ns,
 228                           struct pid *pid)
 229 {
 230         struct ecryptfs_daemon *new_daemon;
 231         struct ecryptfs_daemon *old_daemon;
 232         int rc;
 233
 234         mutex_lock(&ecryptfs_daemon_hash_mux);
 235         rc = ecryptfs_find_daemon_by_euid(&old_daemon, euid, user_ns);
 236         if (rc != 0) {
 237                 printk(KERN_WARNING "Received request from user [%d] "
 238                        "to register daemon [0x%p]; unregistering daemon "
 239                        "[0x%p]\n", euid, pid, old_daemon->pid);
 240                 rc = ecryptfs_send_raw_message(ECRYPTFS_MSG_QUIT, old_daemon);
 241                 if (rc)
 242                         printk(KERN_WARNING "Failed to send QUIT "
 243                                "message to daemon [0x%p]; rc = [%d]\n",
 244                                old_daemon->pid, rc);
 245                 hlist_del(&old_daemon->euid_chain);
 246                 kfree(old_daemon);
 247         }
 248         rc = ecryptfs_spawn_daemon(&new_daemon, euid, user_ns, pid);
 249         if (rc)
 250                 printk(KERN_ERR "%s: The gods are displeased with this attempt "
 251                        "to create a new daemon object for euid [%d]; pid "
 252                        "[0x%p]; rc = [%d]\n", __func__, euid, pid, rc);
 253         mutex_unlock(&ecryptfs_daemon_hash_mux);
 254         return rc;
 255 }
 256
 257 /**
 258  * ecryptfs_exorcise_daemon - Destroy the daemon struct
 259  *
 260  * Must be called ceremoniously while in possession of
 261  * ecryptfs_daemon_hash_mux and the daemon's own mux.
 262  */
 263 int ecryptfs_exorcise_daemon(struct ecryptfs_daemon *daemon)
 264 {
 265         struct ecryptfs_msg_ctx *msg_ctx, *msg_ctx_tmp;
 266         int rc = 0;
 267
 268         mutex_lock(&daemon->mux);
 269         if ((daemon->flags & ECRYPTFS_DAEMON_IN_READ)
 270             || (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)) {
 271                 rc = -EBUSY;
 272                 printk(KERN_WARNING "%s: Attempt to destroy daemon with pid "
 273                        "[0x%p], but it is in the midst of a read or a poll\n",
 274                        __func__, daemon->pid);
 275                 mutex_unlock(&daemon->mux);
 276                 goto out;
 277         }
 278         list_for_each_entry_safe(msg_ctx, msg_ctx_tmp,
 279                                  &daemon->msg_ctx_out_queue, daemon_out_list) {
 280                 list_del(&msg_ctx->daemon_out_list);
 281                 daemon->num_queued_msg_ctx--;
 282                 printk(KERN_WARNING "%s: Warning: dropping message that is in "
 283                        "the out queue of a dying daemon\n", __func__);
 284                 ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
 285         }
 286         hlist_del(&daemon->euid_chain);
 287         if (daemon->task)
 288                 wake_up_process(daemon->task);
 289         if (daemon->pid)
 290                 put_pid(daemon->pid);
 291         if (daemon->user_ns)
 292                 put_user_ns(daemon->user_ns);
 293         mutex_unlock(&daemon->mux);
 294         kzfree(daemon);
 295 out:
 296         return rc;
 297 }
 298
 299 /**
 300  * ecryptfs_process_quit
 301  * @euid: The user ID owner of the message
 302  * @user_ns: The namespace in which @euid applies
 303  * @pid: The process ID for the userspace program that sent the
 304  *       message
 305  *
 306  * Deletes the corresponding daemon for the given euid and pid, if
 307  * it is the registered that is requesting the deletion. Returns zero
 308  * after deleting the desired daemon; non-zero otherwise.
 309  */
 310 int ecryptfs_process_quit(uid_t euid, struct user_namespace *user_ns,
 311                           struct pid *pid)
 312 {
 313         struct ecryptfs_daemon *daemon;
 314         int rc;
 315
 316         mutex_lock(&ecryptfs_daemon_hash_mux);
 317         rc = ecryptfs_find_daemon_by_euid(&daemon, euid, user_ns);
 318         if (rc || !daemon) {
 319                 rc = -EINVAL;
 320                 printk(KERN_ERR "Received request from user [%d] to "
 321                        "unregister unrecognized daemon [0x%p]\n", euid, pid);
 322                 goto out_unlock;
 323         }
 324         rc = ecryptfs_exorcise_daemon(daemon);
 325 out_unlock:
 326         mutex_unlock(&ecryptfs_daemon_hash_mux);
 327         return rc;
 328 }
 329
 330 /**
 331  * ecryptfs_process_reponse
 332  * @msg: The ecryptfs message received; the caller should sanity check
 333  *       msg->data_len and free the memory
 334  * @pid: The process ID of the userspace application that sent the
 335  *       message
 336  * @seq: The sequence number of the message; must match the sequence
 337  *       number for the existing message context waiting for this
 338  *       response
 339  *
 340  * Processes a response message after sending an operation request to
 341  * userspace. Some other process is awaiting this response. Before
 342  * sending out its first communications, the other process allocated a
 343  * msg_ctx from the ecryptfs_msg_ctx_arr at a particular index. The
 344  * response message contains this index so that we can copy over the
 345  * response message into the msg_ctx that the process holds a
 346  * reference to. The other process is going to wake up, check to see
 347  * that msg_ctx->state == ECRYPTFS_MSG_CTX_STATE_DONE, and then
 348  * proceed to read off and process the response message. Returns zero
 349  * upon delivery to desired context element; non-zero upon delivery
 350  * failure or error.
 351  *
 352  * Returns zero on success; non-zero otherwise
 353  */
 354 int ecryptfs_process_response(struct ecryptfs_message *msg, uid_t euid,
 355                               struct user_namespace *user_ns, struct pid *pid,
 356                               u32 seq)
 357 {
 358         struct ecryptfs_daemon *daemon;
 359         struct ecryptfs_msg_ctx *msg_ctx;
 360         size_t msg_size;
 361         struct nsproxy *nsproxy;
 362         struct user_namespace *tsk_user_ns;
 363         uid_t ctx_euid;
 364         int rc;
 365
 366         if (msg->index >= ecryptfs_message_buf_len) {
 367                 rc = -EINVAL;
 368                 printk(KERN_ERR "%s: Attempt to reference "
 369                        "context buffer at index [%d]; maximum "
 370                        "allowable is [%d]\n", __func__, msg->index,
 371                        (ecryptfs_message_buf_len - 1));
 372                 goto out;
 373         }
 374         msg_ctx = &ecryptfs_msg_ctx_arr[msg->index];
 375         mutex_lock(&msg_ctx->mux);
 376         mutex_lock(&ecryptfs_daemon_hash_mux);
 377         rcu_read_lock();
 378         nsproxy = task_nsproxy(msg_ctx->task);
 379         if (nsproxy == NULL) {
 380                 rc = -EBADMSG;
 381                 printk(KERN_ERR "%s: Receiving process is a zombie. Dropping "
 382                        "message.\n", __func__);
 383                 rcu_read_unlock();
 384                 mutex_unlock(&ecryptfs_daemon_hash_mux);
 385                 goto wake_up;
 386         }
 387         tsk_user_ns = __task_cred(msg_ctx->task)->user->user_ns;
 388         ctx_euid = task_euid(msg_ctx->task);
 389         rc = ecryptfs_find_daemon_by_euid(&daemon, ctx_euid, tsk_user_ns);
 390         rcu_read_unlock();
 391         mutex_unlock(&ecryptfs_daemon_hash_mux);
 392         if (rc) {
 393                 rc = -EBADMSG;
 394                 printk(KERN_WARNING "%s: User [%d] received a "
 395                        "message response from process [0x%p] but does "
 396                        "not have a registered daemon\n", __func__,
 397                        ctx_euid, pid);
 398                 goto wake_up;
 399         }
 400         if (ctx_euid != euid) {
 401                 rc = -EBADMSG;
 402                 printk(KERN_WARNING "%s: Received message from user "
 403                        "[%d]; expected message from user [%d]\n", __func__,
 404                        euid, ctx_euid);
 405                 goto unlock;
 406         }
 407         if (tsk_user_ns != user_ns) {
 408                 rc = -EBADMSG;
 409                 printk(KERN_WARNING "%s: Received message from user_ns "
 410                        "[0x%p]; expected message from user_ns [0x%p]\n",
 411                        __func__, user_ns, tsk_user_ns);
 412                 goto unlock;
 413         }
 414         if (daemon->pid != pid) {
 415                 rc = -EBADMSG;
 416                 printk(KERN_ERR "%s: User [%d] sent a message response "
 417                        "from an unrecognized process [0x%p]\n",
 418                        __func__, ctx_euid, pid);
 419                 goto unlock;
 420         }
 421         if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_PENDING) {
 422                 rc = -EINVAL;
 423                 printk(KERN_WARNING "%s: Desired context element is not "
 424                        "pending a response\n", __func__);
 425                 goto unlock;
 426         } else if (msg_ctx->counter != seq) {
 427                 rc = -EINVAL;
 428                 printk(KERN_WARNING "%s: Invalid message sequence; "
 429                        "expected [%d]; received [%d]\n", __func__,
 430                        msg_ctx->counter, seq);
 431                 goto unlock;
 432         }
 433         msg_size = (sizeof(*msg) + msg->data_len);
 434         msg_ctx->msg = kmalloc(msg_size, GFP_KERNEL);
 435         if (!msg_ctx->msg) {
 436                 rc = -ENOMEM;
 437                 printk(KERN_ERR "%s: Failed to allocate [%zd] bytes of "
 438                        "GFP_KERNEL memory\n", __func__, msg_size);
 439                 goto unlock;
 440         }
 441         memcpy(msg_ctx->msg, msg, msg_size);
 442         msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_DONE;
 443         rc = 0;
 444 wake_up:
 445         wake_up_process(msg_ctx->task);
 446 unlock:
 447         mutex_unlock(&msg_ctx->mux);
 448 out:
 449         return rc;
 450 }
 451
 452 /**
 453  * ecryptfs_send_message_locked
 454  * @data: The data to send
 455  * @data_len: The length of data
 456  * @msg_ctx: The message context allocated for the send
 457  *
 458  * Must be called with ecryptfs_daemon_hash_mux held.
 459  *
 460  * Returns zero on success; non-zero otherwise
 461  */
 462 static int
 463 ecryptfs_send_message_locked(char *data, int data_len, u8 msg_type,
 464                              struct ecryptfs_msg_ctx **msg_ctx)
 465 {
 466         struct ecryptfs_daemon *daemon;
 467         uid_t euid = current_euid();
 468         int rc;
 469
 470         rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
 471         if (rc || !daemon) {
 472                 rc = -ENOTCONN;
 473                 printk(KERN_ERR "%s: User [%d] does not have a daemon "
 474                        "registered\n", __func__, euid);
 475                 goto out;
 476         }
 477         mutex_lock(&ecryptfs_msg_ctx_lists_mux);
 478         rc = ecryptfs_acquire_free_msg_ctx(msg_ctx);
 479         if (rc) {
 480                 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
 481                 printk(KERN_WARNING "%s: Could not claim a free "
 482                        "context element\n", __func__);
 483                 goto out;
 484         }
 485         ecryptfs_msg_ctx_free_to_alloc(*msg_ctx);
 486         mutex_unlock(&(*msg_ctx)->mux);
 487         mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
 488         rc = ecryptfs_send_miscdev(data, data_len, *msg_ctx, msg_type, 0,
 489                                    daemon);
 490         if (rc)
 491                 printk(KERN_ERR "%s: Error attempting to send message to "
 492                        "userspace daemon; rc = [%d]\n", __func__, rc);
 493 out:
 494         return rc;
 495 }
 496
 497 /**
 498  * ecryptfs_send_message
 499  * @data: The data to send
 500  * @data_len: The length of data
 501  * @msg_ctx: The message context allocated for the send
 502  *
 503  * Grabs ecryptfs_daemon_hash_mux.
 504  *
 505  * Returns zero on success; non-zero otherwise
 506  */
 507 int ecryptfs_send_message(char *data, int data_len,
 508                           struct ecryptfs_msg_ctx **msg_ctx)
 509 {
 510         int rc;
 511
 512         mutex_lock(&ecryptfs_daemon_hash_mux);
 513         rc = ecryptfs_send_message_locked(data, data_len, ECRYPTFS_MSG_REQUEST,
 514                                           msg_ctx);
 515         mutex_unlock(&ecryptfs_daemon_hash_mux);
 516         return rc;
 517 }
 518
 519 /**
 520  * ecryptfs_wait_for_response
 521  * @msg_ctx: The context that was assigned when sending a message
 522  * @msg: The incoming message from userspace; not set if rc != 0
 523  *
 524  * Sleeps until awaken by ecryptfs_receive_message or until the amount
 525  * of time exceeds ecryptfs_message_wait_timeout.  If zero is
 526  * returned, msg will point to a valid message from userspace; a
 527  * non-zero value is returned upon failure to receive a message or an
 528  * error occurs. Callee must free @msg on success.
 529  */
 530 int ecryptfs_wait_for_response(struct ecryptfs_msg_ctx *msg_ctx,
 531                                struct ecryptfs_message **msg)
 532 {
 533         signed long timeout = ecryptfs_message_wait_timeout * HZ;
 534         int rc = 0;
 535
 536 sleep:
 537         timeout = schedule_timeout_interruptible(timeout);
 538         mutex_lock(&ecryptfs_msg_ctx_lists_mux);
 539         mutex_lock(&msg_ctx->mux);
 540         if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_DONE) {
 541                 if (timeout) {
 542                         mutex_unlock(&msg_ctx->mux);
 543                         mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
 544                         goto sleep;
 545                 }
 546                 rc = -ENOMSG;
 547         } else {
 548                 *msg = msg_ctx->msg;
 549                 msg_ctx->msg = NULL;
 550         }
 551         ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
 552         mutex_unlock(&msg_ctx->mux);
 553         mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
 554         return rc;
 555 }
 556
 557 int ecryptfs_init_messaging(void)
 558 {
 559         int i;
 560         int rc = 0;
 561
 562         if (ecryptfs_number_of_users > ECRYPTFS_MAX_NUM_USERS) {
 563                 ecryptfs_number_of_users = ECRYPTFS_MAX_NUM_USERS;
 564                 printk(KERN_WARNING "%s: Specified number of users is "
 565                        "too large, defaulting to [%d] users\n", __func__,
 566                        ecryptfs_number_of_users);
 567         }
 568         mutex_init(&ecryptfs_daemon_hash_mux);
 569         mutex_lock(&ecryptfs_daemon_hash_mux);
 570         ecryptfs_hash_buckets = 1;
 571         while (ecryptfs_number_of_users >> ecryptfs_hash_buckets)
 572                 ecryptfs_hash_buckets++;
 573         ecryptfs_daemon_hash = kmalloc((sizeof(struct hlist_head)
 574                                         * ecryptfs_hash_buckets), GFP_KERNEL);
 575         if (!ecryptfs_daemon_hash) {
 576                 rc = -ENOMEM;
 577                 printk(KERN_ERR "%s: Failed to allocate memory\n", __func__);
 578                 mutex_unlock(&ecryptfs_daemon_hash_mux);
 579                 goto out;
 580         }
 581         for (i = 0; i < ecryptfs_hash_buckets; i++)
 582                 INIT_HLIST_HEAD(&ecryptfs_daemon_hash[i]);
 583         mutex_unlock(&ecryptfs_daemon_hash_mux);
 584         ecryptfs_msg_ctx_arr = kmalloc((sizeof(struct ecryptfs_msg_ctx)
 585                                         * ecryptfs_message_buf_len),
 586                                        GFP_KERNEL);
 587         if (!ecryptfs_msg_ctx_arr) {
 588                 rc = -ENOMEM;
 589                 printk(KERN_ERR "%s: Failed to allocate memory\n", __func__);
 590                 goto out;
 591         }
 592         mutex_init(&ecryptfs_msg_ctx_lists_mux);
 593         mutex_lock(&ecryptfs_msg_ctx_lists_mux);
 594         ecryptfs_msg_counter = 0;
 595         for (i = 0; i < ecryptfs_message_buf_len; i++) {
 596                 INIT_LIST_HEAD(&ecryptfs_msg_ctx_arr[i].node);
 597                 INIT_LIST_HEAD(&ecryptfs_msg_ctx_arr[i].daemon_out_list);
 598                 mutex_init(&ecryptfs_msg_ctx_arr[i].mux);
 599                 mutex_lock(&ecryptfs_msg_ctx_arr[i].mux);
 600                 ecryptfs_msg_ctx_arr[i].index = i;
 601                 ecryptfs_msg_ctx_arr[i].state = ECRYPTFS_MSG_CTX_STATE_FREE;
 602                 ecryptfs_msg_ctx_arr[i].counter = 0;
 603                 ecryptfs_msg_ctx_arr[i].task = NULL;
 604                 ecryptfs_msg_ctx_arr[i].msg = NULL;
 605                 list_add_tail(&ecryptfs_msg_ctx_arr[i].node,
 606                               &ecryptfs_msg_ctx_free_list);
 607                 mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux);
 608         }
 609         mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
 610         rc = ecryptfs_init_ecryptfs_miscdev();
 611         if (rc)
 612                 ecryptfs_release_messaging();
 613 out:
 614         return rc;
 615 }
 616
 617 void ecryptfs_release_messaging(void)
 618 {
 619         if (ecryptfs_msg_ctx_arr) {
 620                 int i;
 621
 622                 mutex_lock(&ecryptfs_msg_ctx_lists_mux);
 623                 for (i = 0; i < ecryptfs_message_buf_len; i++) {
 624                         mutex_lock(&ecryptfs_msg_ctx_arr[i].mux);
 625                         if (ecryptfs_msg_ctx_arr[i].msg)
 626                                 kfree(ecryptfs_msg_ctx_arr[i].msg);
 627                         mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux);
 628                 }
 629                 kfree(ecryptfs_msg_ctx_arr);
 630                 mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
 631         }
 632         if (ecryptfs_daemon_hash) {
 633                 struct hlist_node *elem;
 634                 struct ecryptfs_daemon *daemon;
 635                 int i;
 636
 637                 mutex_lock(&ecryptfs_daemon_hash_mux);
 638                 for (i = 0; i < ecryptfs_hash_buckets; i++) {
 639                         int rc;
 640
 641                         hlist_for_each_entry(daemon, elem,
 642                                              &ecryptfs_daemon_hash[i],
 643                                              euid_chain) {
 644                                 rc = ecryptfs_exorcise_daemon(daemon);
 645                                 if (rc)
 646                                         printk(KERN_ERR "%s: Error whilst "
 647                                                "attempting to destroy daemon; "
 648                                                "rc = [%d]. Dazed and confused, "
 649                                                "but trying to continue.\n",
 650                                                __func__, rc);
 651                         }
 652                 }
 653                 kfree(ecryptfs_daemon_hash);
 654                 mutex_unlock(&ecryptfs_daemon_hash_mux);
 655         }
 656         ecryptfs_destroy_ecryptfs_miscdev();
 657         return;
 658 }