fs/ecryptfs/main.c

   1 /**
   2  * eCryptfs: Linux filesystem encryption layer
   3  *
   4  * Copyright (C) 1997-2003 Erez Zadok
   5  * Copyright (C) 2001-2003 Stony Brook University
   6  * Copyright (C) 2004-2007 International Business Machines Corp.
   7  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
   8  *              Michael C. Thompson <mcthomps@us.ibm.com>
   9  *              Tyler Hicks <tyhicks@ou.edu>
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License as
  13  * published by the Free Software Foundation; either version 2 of the
  14  * License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful, but
  17  * WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19  * General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  24  * 02111-1307, USA.
  25  */
  26
  27 #include <linux/dcache.h>
  28 #include <linux/file.h>
  29 #include <linux/module.h>
  30 #include <linux/namei.h>
  31 #include <linux/skbuff.h>
  32 #include <linux/crypto.h>
  33 #include <linux/mount.h>
  34 #include <linux/pagemap.h>
  35 #include <linux/key.h>
  36 #include <linux/parser.h>
  37 #include <linux/fs_stack.h>
  38 #include "ecryptfs_kernel.h"
  39
  40 /**
  41  * Module parameter that defines the ecryptfs_verbosity level.
  42  */
  43 int ecryptfs_verbosity = 0;
  44
  45 module_param(ecryptfs_verbosity, int, 0);
  46 MODULE_PARM_DESC(ecryptfs_verbosity,
  47                  "Initial verbosity level (0 or 1; defaults to "
  48                  "0, which is Quiet)");
  49
  50 /**
  51  * Module parameter that defines the number of message buffer elements
  52  */
  53 unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
  54
  55 module_param(ecryptfs_message_buf_len, uint, 0);
  56 MODULE_PARM_DESC(ecryptfs_message_buf_len,
  57                  "Number of message buffer elements");
  58
  59 /**
  60  * Module parameter that defines the maximum guaranteed amount of time to wait
  61  * for a response from ecryptfsd.  The actual sleep time will be, more than
  62  * likely, a small amount greater than this specified value, but only less if
  63  * the message successfully arrives.
  64  */
  65 signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
  66
  67 module_param(ecryptfs_message_wait_timeout, long, 0);
  68 MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
  69                  "Maximum number of seconds that an operation will "
  70                  "sleep while waiting for a message response from "
  71                  "userspace");
  72
  73 /**
  74  * Module parameter that is an estimate of the maximum number of users
  75  * that will be concurrently using eCryptfs. Set this to the right
  76  * value to balance performance and memory use.
  77  */
  78 unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
  79
  80 module_param(ecryptfs_number_of_users, uint, 0);
  81 MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
  82                  "concurrent users of eCryptfs");
  83
  84 void __ecryptfs_printk(const char *fmt, ...)
  85 {
  86         va_list args;
  87         va_start(args, fmt);
  88         if (fmt[1] == '7') { /* KERN_DEBUG */
  89                 if (ecryptfs_verbosity >= 1)
  90                         vprintk(fmt, args);
  91         } else
  92                 vprintk(fmt, args);
  93         va_end(args);
  94 }
  95
  96 /**
  97  * ecryptfs_init_persistent_file
  98  * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
  99  *                   the lower dentry and the lower mount set
 100  *
 101  * eCryptfs only ever keeps a single open file for every lower
 102  * inode. All I/O operations to the lower inode occur through that
 103  * file. When the first eCryptfs dentry that interposes with the first
 104  * lower dentry for that inode is created, this function creates the
 105  * persistent file struct and associates it with the eCryptfs
 106  * inode. When the eCryptfs inode is destroyed, the file is closed.
 107  *
 108  * The persistent file will be opened with read/write permissions, if
 109  * possible. Otherwise, it is opened read-only.
 110  *
 111  * This function does nothing if a lower persistent file is already
 112  * associated with the eCryptfs inode.
 113  *
 114  * Returns zero on success; non-zero otherwise
 115  */
 116 int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry)
 117 {
 118         const struct cred *cred = current_cred();
 119         struct ecryptfs_inode_info *inode_info =
 120                 ecryptfs_inode_to_private(ecryptfs_dentry->d_inode);
 121         int rc = 0;
 122
 123         mutex_lock(&inode_info->lower_file_mutex);
 124         if (!inode_info->lower_file) {
 125                 struct dentry *lower_dentry;
 126                 struct vfsmount *lower_mnt =
 127                         ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
 128
 129                 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 130                 rc = ecryptfs_privileged_open(&inode_info->lower_file,
 131                                               lower_dentry, lower_mnt, cred);
 132                 if (rc) {
 133                         printk(KERN_ERR "Error opening lower persistent file "
 134                                "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
 135                                "rc = [%d]\n", lower_dentry, lower_mnt, rc);
 136                         inode_info->lower_file = NULL;
 137                 }
 138         }
 139         mutex_unlock(&inode_info->lower_file_mutex);
 140         return rc;
 141 }
 142
 143 /**
 144  * ecryptfs_interpose
 145  * @lower_dentry: Existing dentry in the lower filesystem
 146  * @dentry: ecryptfs' dentry
 147  * @sb: ecryptfs's super_block
 148  * @flags: flags to govern behavior of interpose procedure
 149  *
 150  * Interposes upper and lower dentries.
 151  *
 152  * Returns zero on success; non-zero otherwise
 153  */
 154 int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
 155                        struct super_block *sb, u32 flags)
 156 {
 157         struct inode *lower_inode;
 158         struct inode *inode;
 159         int rc = 0;
 160
 161         lower_inode = lower_dentry->d_inode;
 162         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) {
 163                 rc = -EXDEV;
 164                 goto out;
 165         }
 166         if (!igrab(lower_inode)) {
 167                 rc = -ESTALE;
 168                 goto out;
 169         }
 170         inode = iget5_locked(sb, (unsigned long)lower_inode,
 171                              ecryptfs_inode_test, ecryptfs_inode_set,
 172                              lower_inode);
 173         if (!inode) {
 174                 rc = -EACCES;
 175                 iput(lower_inode);
 176                 goto out;
 177         }
 178         if (inode->i_state & I_NEW)
 179                 unlock_new_inode(inode);
 180         else
 181                 iput(lower_inode);
 182         if (S_ISLNK(lower_inode->i_mode))
 183                 inode->i_op = &ecryptfs_symlink_iops;
 184         else if (S_ISDIR(lower_inode->i_mode))
 185                 inode->i_op = &ecryptfs_dir_iops;
 186         if (S_ISDIR(lower_inode->i_mode))
 187                 inode->i_fop = &ecryptfs_dir_fops;
 188         if (special_file(lower_inode->i_mode))
 189                 init_special_inode(inode, lower_inode->i_mode,
 190                                    lower_inode->i_rdev);
 191         dentry->d_op = &ecryptfs_dops;
 192         fsstack_copy_attr_all(inode, lower_inode);
 193         /* This size will be overwritten for real files w/ headers and
 194          * other metadata */
 195         fsstack_copy_inode_size(inode, lower_inode);
 196         if (flags & ECRYPTFS_INTERPOSE_FLAG_D_ADD)
 197                 d_add(dentry, inode);
 198         else
 199                 d_instantiate(dentry, inode);
 200 out:
 201         return rc;
 202 }
 203
 204 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
 205        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
 206        ecryptfs_opt_ecryptfs_key_bytes,
 207        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
 208        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
 209        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
 210        ecryptfs_opt_unlink_sigs, ecryptfs_opt_err };
 211
 212 static const match_table_t tokens = {
 213         {ecryptfs_opt_sig, "sig=%s"},
 214         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 215         {ecryptfs_opt_cipher, "cipher=%s"},
 216         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
 217         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
 218         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
 219         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
 220         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
 221         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
 222         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
 223         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
 224         {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
 225         {ecryptfs_opt_err, NULL}
 226 };
 227
 228 static int ecryptfs_init_global_auth_toks(
 229         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 230 {
 231         struct ecryptfs_global_auth_tok *global_auth_tok;
 232         int rc = 0;
 233
 234         list_for_each_entry(global_auth_tok,
 235                             &mount_crypt_stat->global_auth_tok_list,
 236                             mount_crypt_stat_list) {
 237                 rc = ecryptfs_keyring_auth_tok_for_sig(
 238                         &global_auth_tok->global_auth_tok_key,
 239                         &global_auth_tok->global_auth_tok,
 240                         global_auth_tok->sig);
 241                 if (rc) {
 242                         printk(KERN_ERR "Could not find valid key in user "
 243                                "session keyring for sig specified in mount "
 244                                "option: [%s]\n", global_auth_tok->sig);
 245                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 246                         goto out;
 247                 } else
 248                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
 249         }
 250 out:
 251         return rc;
 252 }
 253
 254 static void ecryptfs_init_mount_crypt_stat(
 255         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 256 {
 257         memset((void *)mount_crypt_stat, 0,
 258                sizeof(struct ecryptfs_mount_crypt_stat));
 259         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
 260         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
 261         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
 262 }
 263
 264 /**
 265  * ecryptfs_parse_options
 266  * @sb: The ecryptfs super block
 267  * @options: The options pased to the kernel
 268  *
 269  * Parse mount options:
 270  * debug=N         - ecryptfs_verbosity level for debug output
 271  * sig=XXX         - description(signature) of the key to use
 272  *
 273  * Returns the dentry object of the lower-level (lower/interposed)
 274  * directory; We want to mount our stackable file system on top of
 275  * that lower directory.
 276  *
 277  * The signature of the key to use must be the description of a key
 278  * already in the keyring. Mounting will fail if the key can not be
 279  * found.
 280  *
 281  * Returns zero on success; non-zero on error
 282  */
 283 static int ecryptfs_parse_options(struct super_block *sb, char *options)
 284 {
 285         char *p;
 286         int rc = 0;
 287         int sig_set = 0;
 288         int cipher_name_set = 0;
 289         int fn_cipher_name_set = 0;
 290         int cipher_key_bytes;
 291         int cipher_key_bytes_set = 0;
 292         int fn_cipher_key_bytes;
 293         int fn_cipher_key_bytes_set = 0;
 294         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 295                 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
 296         substring_t args[MAX_OPT_ARGS];
 297         int token;
 298         char *sig_src;
 299         char *cipher_name_dst;
 300         char *cipher_name_src;
 301         char *fn_cipher_name_dst;
 302         char *fn_cipher_name_src;
 303         char *fnek_dst;
 304         char *fnek_src;
 305         char *cipher_key_bytes_src;
 306         char *fn_cipher_key_bytes_src;
 307
 308         if (!options) {
 309                 rc = -EINVAL;
 310                 goto out;
 311         }
 312         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
 313         while ((p = strsep(&options, ",")) != NULL) {
 314                 if (!*p)
 315                         continue;
 316                 token = match_token(p, tokens, args);
 317                 switch (token) {
 318                 case ecryptfs_opt_sig:
 319                 case ecryptfs_opt_ecryptfs_sig:
 320                         sig_src = args[0].from;
 321                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
 322                                                           sig_src, 0);
 323                         if (rc) {
 324                                 printk(KERN_ERR "Error attempting to register "
 325                                        "global sig; rc = [%d]\n", rc);
 326                                 goto out;
 327                         }
 328                         sig_set = 1;
 329                         break;
 330                 case ecryptfs_opt_cipher:
 331                 case ecryptfs_opt_ecryptfs_cipher:
 332                         cipher_name_src = args[0].from;
 333                         cipher_name_dst =
 334                                 mount_crypt_stat->
 335                                 global_default_cipher_name;
 336                         strncpy(cipher_name_dst, cipher_name_src,
 337                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 338                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 339                         cipher_name_set = 1;
 340                         break;
 341                 case ecryptfs_opt_ecryptfs_key_bytes:
 342                         cipher_key_bytes_src = args[0].from;
 343                         cipher_key_bytes =
 344                                 (int)simple_strtol(cipher_key_bytes_src,
 345                                                    &cipher_key_bytes_src, 0);
 346                         mount_crypt_stat->global_default_cipher_key_size =
 347                                 cipher_key_bytes;
 348                         cipher_key_bytes_set = 1;
 349                         break;
 350                 case ecryptfs_opt_passthrough:
 351                         mount_crypt_stat->flags |=
 352                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 353                         break;
 354                 case ecryptfs_opt_xattr_metadata:
 355                         mount_crypt_stat->flags |=
 356                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 357                         break;
 358                 case ecryptfs_opt_encrypted_view:
 359                         mount_crypt_stat->flags |=
 360                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 361                         mount_crypt_stat->flags |=
 362                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 363                         break;
 364                 case ecryptfs_opt_fnek_sig:
 365                         fnek_src = args[0].from;
 366                         fnek_dst =
 367                                 mount_crypt_stat->global_default_fnek_sig;
 368                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
 369                         mount_crypt_stat->global_default_fnek_sig[
 370                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
 371                         rc = ecryptfs_add_global_auth_tok(
 372                                 mount_crypt_stat,
 373                                 mount_crypt_stat->global_default_fnek_sig,
 374                                 ECRYPTFS_AUTH_TOK_FNEK);
 375                         if (rc) {
 376                                 printk(KERN_ERR "Error attempting to register "
 377                                        "global fnek sig [%s]; rc = [%d]\n",
 378                                        mount_crypt_stat->global_default_fnek_sig,
 379                                        rc);
 380                                 goto out;
 381                         }
 382                         mount_crypt_stat->flags |=
 383                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 384                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 385                         break;
 386                 case ecryptfs_opt_fn_cipher:
 387                         fn_cipher_name_src = args[0].from;
 388                         fn_cipher_name_dst =
 389                                 mount_crypt_stat->global_default_fn_cipher_name;
 390                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
 391                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 392                         mount_crypt_stat->global_default_fn_cipher_name[
 393                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 394                         fn_cipher_name_set = 1;
 395                         break;
 396                 case ecryptfs_opt_fn_cipher_key_bytes:
 397                         fn_cipher_key_bytes_src = args[0].from;
 398                         fn_cipher_key_bytes =
 399                                 (int)simple_strtol(fn_cipher_key_bytes_src,
 400                                                    &fn_cipher_key_bytes_src, 0);
 401                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
 402                                 fn_cipher_key_bytes;
 403                         fn_cipher_key_bytes_set = 1;
 404                         break;
 405                 case ecryptfs_opt_unlink_sigs:
 406                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
 407                         break;
 408                 case ecryptfs_opt_err:
 409                 default:
 410                         printk(KERN_WARNING
 411                                "%s: eCryptfs: unrecognized option [%s]\n",
 412                                __func__, p);
 413                 }
 414         }
 415         if (!sig_set) {
 416                 rc = -EINVAL;
 417                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
 418                                 "auth tok signature as a mount "
 419                                 "parameter; see the eCryptfs README\n");
 420                 goto out;
 421         }
 422         if (!cipher_name_set) {
 423                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 424
 425                 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 426                 strcpy(mount_crypt_stat->global_default_cipher_name,
 427                        ECRYPTFS_DEFAULT_CIPHER);
 428         }
 429         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 430             && !fn_cipher_name_set)
 431                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
 432                        mount_crypt_stat->global_default_cipher_name);
 433         if (!cipher_key_bytes_set)
 434                 mount_crypt_stat->global_default_cipher_key_size = 0;
 435         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 436             && !fn_cipher_key_bytes_set)
 437                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
 438                         mount_crypt_stat->global_default_cipher_key_size;
 439         mutex_lock(&key_tfm_list_mutex);
 440         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
 441                                  NULL)) {
 442                 rc = ecryptfs_add_new_key_tfm(
 443                         NULL, mount_crypt_stat->global_default_cipher_name,
 444                         mount_crypt_stat->global_default_cipher_key_size);
 445                 if (rc) {
 446                         printk(KERN_ERR "Error attempting to initialize "
 447                                "cipher with name = [%s] and key size = [%td]; "
 448                                "rc = [%d]\n",
 449                                mount_crypt_stat->global_default_cipher_name,
 450                                mount_crypt_stat->global_default_cipher_key_size,
 451                                rc);
 452                         rc = -EINVAL;
 453                         mutex_unlock(&key_tfm_list_mutex);
 454                         goto out;
 455                 }
 456         }
 457         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 458             && !ecryptfs_tfm_exists(
 459                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
 460                 rc = ecryptfs_add_new_key_tfm(
 461                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
 462                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
 463                 if (rc) {
 464                         printk(KERN_ERR "Error attempting to initialize "
 465                                "cipher with name = [%s] and key size = [%td]; "
 466                                "rc = [%d]\n",
 467                                mount_crypt_stat->global_default_fn_cipher_name,
 468                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
 469                                rc);
 470                         rc = -EINVAL;
 471                         mutex_unlock(&key_tfm_list_mutex);
 472                         goto out;
 473                 }
 474         }
 475         mutex_unlock(&key_tfm_list_mutex);
 476         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
 477         if (rc)
 478                 printk(KERN_WARNING "One or more global auth toks could not "
 479                        "properly register; rc = [%d]\n", rc);
 480 out:
 481         return rc;
 482 }
 483
 484 struct kmem_cache *ecryptfs_sb_info_cache;
 485
 486 /**
 487  * ecryptfs_fill_super
 488  * @sb: The ecryptfs super block
 489  * @raw_data: The options passed to mount
 490  * @silent: Not used but required by function prototype
 491  *
 492  * Sets up what we can of the sb, rest is done in ecryptfs_read_super
 493  *
 494  * Returns zero on success; non-zero otherwise
 495  */
 496 static int
 497 ecryptfs_fill_super(struct super_block *sb, void *raw_data, int silent)
 498 {
 499         int rc = 0;
 500
 501         /* Released in ecryptfs_put_super() */
 502         ecryptfs_set_superblock_private(sb,
 503                                         kmem_cache_zalloc(ecryptfs_sb_info_cache,
 504                                                          GFP_KERNEL));
 505         if (!ecryptfs_superblock_to_private(sb)) {
 506                 ecryptfs_printk(KERN_WARNING, "Out of memory\n");
 507                 rc = -ENOMEM;
 508                 goto out;
 509         }
 510         sb->s_op = &ecryptfs_sops;
 511         /* Released through deactivate_super(sb) from get_sb_nodev */
 512         sb->s_root = d_alloc(NULL, &(const struct qstr) {
 513                              .hash = 0,.name = "/",.len = 1});
 514         if (!sb->s_root) {
 515                 ecryptfs_printk(KERN_ERR, "d_alloc failed\n");
 516                 rc = -ENOMEM;
 517                 goto out;
 518         }
 519         sb->s_root->d_op = &ecryptfs_dops;
 520         sb->s_root->d_sb = sb;
 521         sb->s_root->d_parent = sb->s_root;
 522         /* Released in d_release when dput(sb->s_root) is called */
 523         /* through deactivate_super(sb) from get_sb_nodev() */
 524         ecryptfs_set_dentry_private(sb->s_root,
 525                                     kmem_cache_zalloc(ecryptfs_dentry_info_cache,
 526                                                      GFP_KERNEL));
 527         if (!ecryptfs_dentry_to_private(sb->s_root)) {
 528                 ecryptfs_printk(KERN_ERR,
 529                                 "dentry_info_cache alloc failed\n");
 530                 rc = -ENOMEM;
 531                 goto out;
 532         }
 533         rc = 0;
 534 out:
 535         /* Should be able to rely on deactivate_super called from
 536          * get_sb_nodev */
 537         return rc;
 538 }
 539
 540 /**
 541  * ecryptfs_read_super
 542  * @sb: The ecryptfs super block
 543  * @dev_name: The path to mount over
 544  *
 545  * Read the super block of the lower filesystem, and use
 546  * ecryptfs_interpose to create our initial inode and super block
 547  * struct.
 548  */
 549 static int ecryptfs_read_super(struct super_block *sb, const char *dev_name)
 550 {
 551         struct path path;
 552         int rc;
 553
 554         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 555         if (rc) {
 556                 ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n");
 557                 goto out;
 558         }
 559         ecryptfs_set_superblock_lower(sb, path.dentry->d_sb);
 560         sb->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 561         sb->s_blocksize = path.dentry->d_sb->s_blocksize;
 562         ecryptfs_set_dentry_lower(sb->s_root, path.dentry);
 563         ecryptfs_set_dentry_lower_mnt(sb->s_root, path.mnt);
 564         rc = ecryptfs_interpose(path.dentry, sb->s_root, sb, 0);
 565         if (rc)
 566                 goto out_free;
 567         rc = 0;
 568         goto out;
 569 out_free:
 570         path_put(&path);
 571 out:
 572         return rc;
 573 }
 574
 575 /**
 576  * ecryptfs_get_sb
 577  * @fs_type
 578  * @flags
 579  * @dev_name: The path to mount over
 580  * @raw_data: The options passed into the kernel
 581  *
 582  * The whole ecryptfs_get_sb process is broken into 4 functions:
 583  * ecryptfs_parse_options(): handle options passed to ecryptfs, if any
 584  * ecryptfs_fill_super(): used by get_sb_nodev, fills out the super_block
 585  *                        with as much information as it can before needing
 586  *                        the lower filesystem.
 587  * ecryptfs_read_super(): this accesses the lower filesystem and uses
 588  *                        ecryptfs_interpolate to perform most of the linking
 589  * ecryptfs_interpolate(): links the lower filesystem into ecryptfs
 590  */
 591 static int ecryptfs_get_sb(struct file_system_type *fs_type, int flags,
 592                         const char *dev_name, void *raw_data,
 593                         struct vfsmount *mnt)
 594 {
 595         int rc;
 596         struct super_block *sb;
 597
 598         rc = get_sb_nodev(fs_type, flags, raw_data, ecryptfs_fill_super, mnt);
 599         if (rc < 0) {
 600                 printk(KERN_ERR "Getting sb failed; rc = [%d]\n", rc);
 601                 goto out;
 602         }
 603         sb = mnt->mnt_sb;
 604         rc = ecryptfs_parse_options(sb, raw_data);
 605         if (rc) {
 606                 printk(KERN_ERR "Error parsing options; rc = [%d]\n", rc);
 607                 goto out_abort;
 608         }
 609         rc = ecryptfs_read_super(sb, dev_name);
 610         if (rc) {
 611                 printk(KERN_ERR "Reading sb failed; rc = [%d]\n", rc);
 612                 goto out_abort;
 613         }
 614         goto out;
 615 out_abort:
 616         dput(sb->s_root); /* aka mnt->mnt_root, as set by get_sb_nodev() */
 617         deactivate_locked_super(sb);
 618 out:
 619         return rc;
 620 }
 621
 622 /**
 623  * ecryptfs_kill_block_super
 624  * @sb: The ecryptfs super block
 625  *
 626  * Used to bring the superblock down and free the private data.
 627  * Private data is free'd in ecryptfs_put_super()
 628  */
 629 static void ecryptfs_kill_block_super(struct super_block *sb)
 630 {
 631         generic_shutdown_super(sb);
 632 }
 633
 634 static struct file_system_type ecryptfs_fs_type = {
 635         .owner = THIS_MODULE,
 636         .name = "ecryptfs",
 637         .get_sb = ecryptfs_get_sb,
 638         .kill_sb = ecryptfs_kill_block_super,
 639         .fs_flags = 0
 640 };
 641
 642 /**
 643  * inode_info_init_once
 644  *
 645  * Initializes the ecryptfs_inode_info_cache when it is created
 646  */
 647 static void
 648 inode_info_init_once(void *vptr)
 649 {
 650         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 651
 652         inode_init_once(&ei->vfs_inode);
 653 }
 654
 655 static struct ecryptfs_cache_info {
 656         struct kmem_cache **cache;
 657         const char *name;
 658         size_t size;
 659         void (*ctor)(void *obj);
 660 } ecryptfs_cache_infos[] = {
 661         {
 662                 .cache = &ecryptfs_auth_tok_list_item_cache,
 663                 .name = "ecryptfs_auth_tok_list_item",
 664                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 665         },
 666         {
 667                 .cache = &ecryptfs_file_info_cache,
 668                 .name = "ecryptfs_file_cache",
 669                 .size = sizeof(struct ecryptfs_file_info),
 670         },
 671         {
 672                 .cache = &ecryptfs_dentry_info_cache,
 673                 .name = "ecryptfs_dentry_info_cache",
 674                 .size = sizeof(struct ecryptfs_dentry_info),
 675         },
 676         {
 677                 .cache = &ecryptfs_inode_info_cache,
 678                 .name = "ecryptfs_inode_cache",
 679                 .size = sizeof(struct ecryptfs_inode_info),
 680                 .ctor = inode_info_init_once,
 681         },
 682         {
 683                 .cache = &ecryptfs_sb_info_cache,
 684                 .name = "ecryptfs_sb_cache",
 685                 .size = sizeof(struct ecryptfs_sb_info),
 686         },
 687         {
 688                 .cache = &ecryptfs_header_cache_1,
 689                 .name = "ecryptfs_headers_1",
 690                 .size = PAGE_CACHE_SIZE,
 691         },
 692         {
 693                 .cache = &ecryptfs_header_cache_2,
 694                 .name = "ecryptfs_headers_2",
 695                 .size = PAGE_CACHE_SIZE,
 696         },
 697         {
 698                 .cache = &ecryptfs_xattr_cache,
 699                 .name = "ecryptfs_xattr_cache",
 700                 .size = PAGE_CACHE_SIZE,
 701         },
 702         {
 703                 .cache = &ecryptfs_key_record_cache,
 704                 .name = "ecryptfs_key_record_cache",
 705                 .size = sizeof(struct ecryptfs_key_record),
 706         },
 707         {
 708                 .cache = &ecryptfs_key_sig_cache,
 709                 .name = "ecryptfs_key_sig_cache",
 710                 .size = sizeof(struct ecryptfs_key_sig),
 711         },
 712         {
 713                 .cache = &ecryptfs_global_auth_tok_cache,
 714                 .name = "ecryptfs_global_auth_tok_cache",
 715                 .size = sizeof(struct ecryptfs_global_auth_tok),
 716         },
 717         {
 718                 .cache = &ecryptfs_key_tfm_cache,
 719                 .name = "ecryptfs_key_tfm_cache",
 720                 .size = sizeof(struct ecryptfs_key_tfm),
 721         },
 722         {
 723                 .cache = &ecryptfs_open_req_cache,
 724                 .name = "ecryptfs_open_req_cache",
 725                 .size = sizeof(struct ecryptfs_open_req),
 726         },
 727 };
 728
 729 static void ecryptfs_free_kmem_caches(void)
 730 {
 731         int i;
 732
 733         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 734                 struct ecryptfs_cache_info *info;
 735
 736                 info = &ecryptfs_cache_infos[i];
 737                 if (*(info->cache))
 738                         kmem_cache_destroy(*(info->cache));
 739         }
 740 }
 741
 742 /**
 743  * ecryptfs_init_kmem_caches
 744  *
 745  * Returns zero on success; non-zero otherwise
 746  */
 747 static int ecryptfs_init_kmem_caches(void)
 748 {
 749         int i;
 750
 751         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 752                 struct ecryptfs_cache_info *info;
 753
 754                 info = &ecryptfs_cache_infos[i];
 755                 *(info->cache) = kmem_cache_create(info->name, info->size,
 756                                 0, SLAB_HWCACHE_ALIGN, info->ctor);
 757                 if (!*(info->cache)) {
 758                         ecryptfs_free_kmem_caches();
 759                         ecryptfs_printk(KERN_WARNING, "%s: "
 760                                         "kmem_cache_create failed\n",
 761                                         info->name);
 762                         return -ENOMEM;
 763                 }
 764         }
 765         return 0;
 766 }
 767
 768 static struct kobject *ecryptfs_kobj;
 769
 770 static ssize_t version_show(struct kobject *kobj,
 771                             struct kobj_attribute *attr, char *buff)
 772 {
 773         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 774 }
 775
 776 static struct kobj_attribute version_attr = __ATTR_RO(version);
 777
 778 static struct attribute *attributes[] = {
 779         &version_attr.attr,
 780         NULL,
 781 };
 782
 783 static struct attribute_group attr_group = {
 784         .attrs = attributes,
 785 };
 786
 787 static int do_sysfs_registration(void)
 788 {
 789         int rc;
 790
 791         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 792         if (!ecryptfs_kobj) {
 793                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
 794                 rc = -ENOMEM;
 795                 goto out;
 796         }
 797         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 798         if (rc) {
 799                 printk(KERN_ERR
 800                        "Unable to create ecryptfs version attributes\n");
 801                 kobject_put(ecryptfs_kobj);
 802         }
 803 out:
 804         return rc;
 805 }
 806
 807 static void do_sysfs_unregistration(void)
 808 {
 809         sysfs_remove_group(ecryptfs_kobj, &attr_group);
 810         kobject_put(ecryptfs_kobj);
 811 }
 812
 813 static int __init ecryptfs_init(void)
 814 {
 815         int rc;
 816
 817         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
 818                 rc = -EINVAL;
 819                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 820                                 "larger than the host's page size, and so "
 821                                 "eCryptfs cannot run on this system. The "
 822                                 "default eCryptfs extent size is [%d] bytes; "
 823                                 "the page size is [%d] bytes.\n",
 824                                 ECRYPTFS_DEFAULT_EXTENT_SIZE, PAGE_CACHE_SIZE);
 825                 goto out;
 826         }
 827         rc = ecryptfs_init_kmem_caches();
 828         if (rc) {
 829                 printk(KERN_ERR
 830                        "Failed to allocate one or more kmem_cache objects\n");
 831                 goto out;
 832         }
 833         rc = register_filesystem(&ecryptfs_fs_type);
 834         if (rc) {
 835                 printk(KERN_ERR "Failed to register filesystem\n");
 836                 goto out_free_kmem_caches;
 837         }
 838         rc = do_sysfs_registration();
 839         if (rc) {
 840                 printk(KERN_ERR "sysfs registration failed\n");
 841                 goto out_unregister_filesystem;
 842         }
 843         rc = ecryptfs_init_kthread();
 844         if (rc) {
 845                 printk(KERN_ERR "%s: kthread initialization failed; "
 846                        "rc = [%d]\n", __func__, rc);
 847                 goto out_do_sysfs_unregistration;
 848         }
 849         rc = ecryptfs_init_messaging();
 850         if (rc) {
 851                 printk(KERN_ERR "Failure occured while attempting to "
 852                                 "initialize the communications channel to "
 853                                 "ecryptfsd\n");
 854                 goto out_destroy_kthread;
 855         }
 856         rc = ecryptfs_init_crypto();
 857         if (rc) {
 858                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
 859                        "rc = [%d]\n", rc);
 860                 goto out_release_messaging;
 861         }
 862         if (ecryptfs_verbosity > 0)
 863                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 864                         "will be written to the syslog!\n", ecryptfs_verbosity);
 865
 866         goto out;
 867 out_release_messaging:
 868         ecryptfs_release_messaging();
 869 out_destroy_kthread:
 870         ecryptfs_destroy_kthread();
 871 out_do_sysfs_unregistration:
 872         do_sysfs_unregistration();
 873 out_unregister_filesystem:
 874         unregister_filesystem(&ecryptfs_fs_type);
 875 out_free_kmem_caches:
 876         ecryptfs_free_kmem_caches();
 877 out:
 878         return rc;
 879 }
 880
 881 static void __exit ecryptfs_exit(void)
 882 {
 883         int rc;
 884
 885         rc = ecryptfs_destroy_crypto();
 886         if (rc)
 887                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 888                        "rc = [%d]\n", rc);
 889         ecryptfs_release_messaging();
 890         ecryptfs_destroy_kthread();
 891         do_sysfs_unregistration();
 892         unregister_filesystem(&ecryptfs_fs_type);
 893         ecryptfs_free_kmem_caches();
 894 }
 895
 896 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 897 MODULE_DESCRIPTION("eCryptfs");
 898
 899 MODULE_LICENSE("GPL");
 900
 901 module_init(ecryptfs_init)
 902 module_exit(ecryptfs_exit)