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 <linux/slab.h>
  39 #include <linux/magic.h>
  40 #include "ecryptfs_kernel.h"
  41
  42 /**
  43  * Module parameter that defines the ecryptfs_verbosity level.
  44  */
  45 int ecryptfs_verbosity = 0;
  46
  47 module_param(ecryptfs_verbosity, int, 0);
  48 MODULE_PARM_DESC(ecryptfs_verbosity,
  49                  "Initial verbosity level (0 or 1; defaults to "
  50                  "0, which is Quiet)");
  51
  52 /**
  53  * Module parameter that defines the number of message buffer elements
  54  */
  55 unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
  56
  57 module_param(ecryptfs_message_buf_len, uint, 0);
  58 MODULE_PARM_DESC(ecryptfs_message_buf_len,
  59                  "Number of message buffer elements");
  60
  61 /**
  62  * Module parameter that defines the maximum guaranteed amount of time to wait
  63  * for a response from ecryptfsd.  The actual sleep time will be, more than
  64  * likely, a small amount greater than this specified value, but only less if
  65  * the message successfully arrives.
  66  */
  67 signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
  68
  69 module_param(ecryptfs_message_wait_timeout, long, 0);
  70 MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
  71                  "Maximum number of seconds that an operation will "
  72                  "sleep while waiting for a message response from "
  73                  "userspace");
  74
  75 /**
  76  * Module parameter that is an estimate of the maximum number of users
  77  * that will be concurrently using eCryptfs. Set this to the right
  78  * value to balance performance and memory use.
  79  */
  80 unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
  81
  82 module_param(ecryptfs_number_of_users, uint, 0);
  83 MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
  84                  "concurrent users of eCryptfs");
  85
  86 void __ecryptfs_printk(const char *fmt, ...)
  87 {
  88         va_list args;
  89         va_start(args, fmt);
  90         if (fmt[1] == '7') { /* KERN_DEBUG */
  91                 if (ecryptfs_verbosity >= 1)
  92                         vprintk(fmt, args);
  93         } else
  94                 vprintk(fmt, args);
  95         va_end(args);
  96 }
  97
  98 /**
  99  * ecryptfs_init_lower_file
 100  * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
 101  *                   the lower dentry and the lower mount set
 102  *
 103  * eCryptfs only ever keeps a single open file for every lower
 104  * inode. All I/O operations to the lower inode occur through that
 105  * file. When the first eCryptfs dentry that interposes with the first
 106  * lower dentry for that inode is created, this function creates the
 107  * lower file struct and associates it with the eCryptfs
 108  * inode. When all eCryptfs files associated with the inode are released, the
 109  * file is closed.
 110  *
 111  * The lower file will be opened with read/write permissions, if
 112  * possible. Otherwise, it is opened read-only.
 113  *
 114  * This function does nothing if a lower file is already
 115  * associated with the eCryptfs inode.
 116  *
 117  * Returns zero on success; non-zero otherwise
 118  */
 119 static int ecryptfs_init_lower_file(struct dentry *dentry,
 120                                     struct file **lower_file)
 121 {
 122         const struct cred *cred = current_cred();
 123         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 124         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 125         int rc;
 126
 127         rc = ecryptfs_privileged_open(lower_file, lower_dentry, lower_mnt,
 128                                       cred);
 129         if (rc) {
 130                 printk(KERN_ERR "Error opening lower file "
 131                        "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
 132                        "rc = [%d]\n", lower_dentry, lower_mnt, rc);
 133                 (*lower_file) = NULL;
 134         }
 135         return rc;
 136 }
 137
 138 int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
 139 {
 140         struct ecryptfs_inode_info *inode_info;
 141         int count, rc = 0;
 142
 143         inode_info = ecryptfs_inode_to_private(inode);
 144         mutex_lock(&inode_info->lower_file_mutex);
 145         count = atomic_inc_return(&inode_info->lower_file_count);
 146         if (WARN_ON_ONCE(count < 1))
 147                 rc = -EINVAL;
 148         else if (count == 1) {
 149                 rc = ecryptfs_init_lower_file(dentry,
 150                                               &inode_info->lower_file);
 151                 if (rc)
 152                         atomic_set(&inode_info->lower_file_count, 0);
 153         }
 154         mutex_unlock(&inode_info->lower_file_mutex);
 155         return rc;
 156 }
 157
 158 void ecryptfs_put_lower_file(struct inode *inode)
 159 {
 160         struct ecryptfs_inode_info *inode_info;
 161
 162         inode_info = ecryptfs_inode_to_private(inode);
 163         if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
 164                                       &inode_info->lower_file_mutex)) {
 165                 filemap_write_and_wait(inode->i_mapping);
 166                 fput(inode_info->lower_file);
 167                 inode_info->lower_file = NULL;
 168                 mutex_unlock(&inode_info->lower_file_mutex);
 169         }
 170 }
 171
 172 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
 173        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
 174        ecryptfs_opt_ecryptfs_key_bytes,
 175        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
 176        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
 177        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
 178        ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
 179        ecryptfs_opt_check_dev_ruid,
 180        ecryptfs_opt_err };
 181
 182 static const match_table_t tokens = {
 183         {ecryptfs_opt_sig, "sig=%s"},
 184         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 185         {ecryptfs_opt_cipher, "cipher=%s"},
 186         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
 187         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
 188         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
 189         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
 190         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
 191         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
 192         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
 193         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
 194         {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
 195         {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
 196         {ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
 197         {ecryptfs_opt_err, NULL}
 198 };
 199
 200 static int ecryptfs_init_global_auth_toks(
 201         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 202 {
 203         struct ecryptfs_global_auth_tok *global_auth_tok;
 204         struct ecryptfs_auth_tok *auth_tok;
 205         int rc = 0;
 206
 207         list_for_each_entry(global_auth_tok,
 208                             &mount_crypt_stat->global_auth_tok_list,
 209                             mount_crypt_stat_list) {
 210                 rc = ecryptfs_keyring_auth_tok_for_sig(
 211                         &global_auth_tok->global_auth_tok_key, &auth_tok,
 212                         global_auth_tok->sig);
 213                 if (rc) {
 214                         printk(KERN_ERR "Could not find valid key in user "
 215                                "session keyring for sig specified in mount "
 216                                "option: [%s]\n", global_auth_tok->sig);
 217                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 218                         goto out;
 219                 } else {
 220                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
 221                         up_write(&(global_auth_tok->global_auth_tok_key)->sem);
 222                 }
 223         }
 224 out:
 225         return rc;
 226 }
 227
 228 static void ecryptfs_init_mount_crypt_stat(
 229         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 230 {
 231         memset((void *)mount_crypt_stat, 0,
 232                sizeof(struct ecryptfs_mount_crypt_stat));
 233         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
 234         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
 235         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
 236 }
 237
 238 /**
 239  * ecryptfs_parse_options
 240  * @sb: The ecryptfs super block
 241  * @options: The options passed to the kernel
 242  * @check_ruid: set to 1 if device uid should be checked against the ruid
 243  *
 244  * Parse mount options:
 245  * debug=N         - ecryptfs_verbosity level for debug output
 246  * sig=XXX         - description(signature) of the key to use
 247  *
 248  * Returns the dentry object of the lower-level (lower/interposed)
 249  * directory; We want to mount our stackable file system on top of
 250  * that lower directory.
 251  *
 252  * The signature of the key to use must be the description of a key
 253  * already in the keyring. Mounting will fail if the key can not be
 254  * found.
 255  *
 256  * Returns zero on success; non-zero on error
 257  */
 258 static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
 259                                   uid_t *check_ruid)
 260 {
 261         char *p;
 262         int rc = 0;
 263         int sig_set = 0;
 264         int cipher_name_set = 0;
 265         int fn_cipher_name_set = 0;
 266         int cipher_key_bytes;
 267         int cipher_key_bytes_set = 0;
 268         int fn_cipher_key_bytes;
 269         int fn_cipher_key_bytes_set = 0;
 270         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 271                 &sbi->mount_crypt_stat;
 272         substring_t args[MAX_OPT_ARGS];
 273         int token;
 274         char *sig_src;
 275         char *cipher_name_dst;
 276         char *cipher_name_src;
 277         char *fn_cipher_name_dst;
 278         char *fn_cipher_name_src;
 279         char *fnek_dst;
 280         char *fnek_src;
 281         char *cipher_key_bytes_src;
 282         char *fn_cipher_key_bytes_src;
 283
 284         *check_ruid = 0;
 285
 286         if (!options) {
 287                 rc = -EINVAL;
 288                 goto out;
 289         }
 290         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
 291         while ((p = strsep(&options, ",")) != NULL) {
 292                 if (!*p)
 293                         continue;
 294                 token = match_token(p, tokens, args);
 295                 switch (token) {
 296                 case ecryptfs_opt_sig:
 297                 case ecryptfs_opt_ecryptfs_sig:
 298                         sig_src = args[0].from;
 299                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
 300                                                           sig_src, 0);
 301                         if (rc) {
 302                                 printk(KERN_ERR "Error attempting to register "
 303                                        "global sig; rc = [%d]\n", rc);
 304                                 goto out;
 305                         }
 306                         sig_set = 1;
 307                         break;
 308                 case ecryptfs_opt_cipher:
 309                 case ecryptfs_opt_ecryptfs_cipher:
 310                         cipher_name_src = args[0].from;
 311                         cipher_name_dst =
 312                                 mount_crypt_stat->
 313                                 global_default_cipher_name;
 314                         strncpy(cipher_name_dst, cipher_name_src,
 315                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 316                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 317                         cipher_name_set = 1;
 318                         break;
 319                 case ecryptfs_opt_ecryptfs_key_bytes:
 320                         cipher_key_bytes_src = args[0].from;
 321                         cipher_key_bytes =
 322                                 (int)simple_strtol(cipher_key_bytes_src,
 323                                                    &cipher_key_bytes_src, 0);
 324                         mount_crypt_stat->global_default_cipher_key_size =
 325                                 cipher_key_bytes;
 326                         cipher_key_bytes_set = 1;
 327                         break;
 328                 case ecryptfs_opt_passthrough:
 329                         mount_crypt_stat->flags |=
 330                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 331                         break;
 332                 case ecryptfs_opt_xattr_metadata:
 333                         mount_crypt_stat->flags |=
 334                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 335                         break;
 336                 case ecryptfs_opt_encrypted_view:
 337                         mount_crypt_stat->flags |=
 338                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 339                         mount_crypt_stat->flags |=
 340                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 341                         break;
 342                 case ecryptfs_opt_fnek_sig:
 343                         fnek_src = args[0].from;
 344                         fnek_dst =
 345                                 mount_crypt_stat->global_default_fnek_sig;
 346                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
 347                         mount_crypt_stat->global_default_fnek_sig[
 348                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
 349                         rc = ecryptfs_add_global_auth_tok(
 350                                 mount_crypt_stat,
 351                                 mount_crypt_stat->global_default_fnek_sig,
 352                                 ECRYPTFS_AUTH_TOK_FNEK);
 353                         if (rc) {
 354                                 printk(KERN_ERR "Error attempting to register "
 355                                        "global fnek sig [%s]; rc = [%d]\n",
 356                                        mount_crypt_stat->global_default_fnek_sig,
 357                                        rc);
 358                                 goto out;
 359                         }
 360                         mount_crypt_stat->flags |=
 361                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 362                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 363                         break;
 364                 case ecryptfs_opt_fn_cipher:
 365                         fn_cipher_name_src = args[0].from;
 366                         fn_cipher_name_dst =
 367                                 mount_crypt_stat->global_default_fn_cipher_name;
 368                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
 369                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 370                         mount_crypt_stat->global_default_fn_cipher_name[
 371                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 372                         fn_cipher_name_set = 1;
 373                         break;
 374                 case ecryptfs_opt_fn_cipher_key_bytes:
 375                         fn_cipher_key_bytes_src = args[0].from;
 376                         fn_cipher_key_bytes =
 377                                 (int)simple_strtol(fn_cipher_key_bytes_src,
 378                                                    &fn_cipher_key_bytes_src, 0);
 379                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
 380                                 fn_cipher_key_bytes;
 381                         fn_cipher_key_bytes_set = 1;
 382                         break;
 383                 case ecryptfs_opt_unlink_sigs:
 384                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
 385                         break;
 386                 case ecryptfs_opt_mount_auth_tok_only:
 387                         mount_crypt_stat->flags |=
 388                                 ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
 389                         break;
 390                 case ecryptfs_opt_check_dev_ruid:
 391                         *check_ruid = 1;
 392                         break;
 393                 case ecryptfs_opt_err:
 394                 default:
 395                         printk(KERN_WARNING
 396                                "%s: eCryptfs: unrecognized option [%s]\n",
 397                                __func__, p);
 398                 }
 399         }
 400         if (!sig_set) {
 401                 rc = -EINVAL;
 402                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
 403                                 "auth tok signature as a mount "
 404                                 "parameter; see the eCryptfs README\n");
 405                 goto out;
 406         }
 407         if (!cipher_name_set) {
 408                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 409
 410                 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 411                 strcpy(mount_crypt_stat->global_default_cipher_name,
 412                        ECRYPTFS_DEFAULT_CIPHER);
 413         }
 414         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 415             && !fn_cipher_name_set)
 416                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
 417                        mount_crypt_stat->global_default_cipher_name);
 418         if (!cipher_key_bytes_set)
 419                 mount_crypt_stat->global_default_cipher_key_size = 0;
 420         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 421             && !fn_cipher_key_bytes_set)
 422                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
 423                         mount_crypt_stat->global_default_cipher_key_size;
 424         mutex_lock(&key_tfm_list_mutex);
 425         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
 426                                  NULL)) {
 427                 rc = ecryptfs_add_new_key_tfm(
 428                         NULL, mount_crypt_stat->global_default_cipher_name,
 429                         mount_crypt_stat->global_default_cipher_key_size);
 430                 if (rc) {
 431                         printk(KERN_ERR "Error attempting to initialize "
 432                                "cipher with name = [%s] and key size = [%td]; "
 433                                "rc = [%d]\n",
 434                                mount_crypt_stat->global_default_cipher_name,
 435                                mount_crypt_stat->global_default_cipher_key_size,
 436                                rc);
 437                         rc = -EINVAL;
 438                         mutex_unlock(&key_tfm_list_mutex);
 439                         goto out;
 440                 }
 441         }
 442         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 443             && !ecryptfs_tfm_exists(
 444                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
 445                 rc = ecryptfs_add_new_key_tfm(
 446                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
 447                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
 448                 if (rc) {
 449                         printk(KERN_ERR "Error attempting to initialize "
 450                                "cipher with name = [%s] and key size = [%td]; "
 451                                "rc = [%d]\n",
 452                                mount_crypt_stat->global_default_fn_cipher_name,
 453                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
 454                                rc);
 455                         rc = -EINVAL;
 456                         mutex_unlock(&key_tfm_list_mutex);
 457                         goto out;
 458                 }
 459         }
 460         mutex_unlock(&key_tfm_list_mutex);
 461         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
 462         if (rc)
 463                 printk(KERN_WARNING "One or more global auth toks could not "
 464                        "properly register; rc = [%d]\n", rc);
 465 out:
 466         return rc;
 467 }
 468
 469 struct kmem_cache *ecryptfs_sb_info_cache;
 470 static struct file_system_type ecryptfs_fs_type;
 471
 472 /**
 473  * ecryptfs_get_sb
 474  * @fs_type
 475  * @flags
 476  * @dev_name: The path to mount over
 477  * @raw_data: The options passed into the kernel
 478  */
 479 static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
 480                         const char *dev_name, void *raw_data)
 481 {
 482         struct super_block *s;
 483         struct ecryptfs_sb_info *sbi;
 484         struct ecryptfs_dentry_info *root_info;
 485         const char *err = "Getting sb failed";
 486         struct inode *inode;
 487         struct path path;
 488         uid_t check_ruid;
 489         int rc;
 490
 491         sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
 492         if (!sbi) {
 493                 rc = -ENOMEM;
 494                 goto out;
 495         }
 496
 497         rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
 498         if (rc) {
 499                 err = "Error parsing options";
 500                 goto out;
 501         }
 502
 503         s = sget(fs_type, NULL, set_anon_super, NULL);
 504         if (IS_ERR(s)) {
 505                 rc = PTR_ERR(s);
 506                 goto out;
 507         }
 508
 509         s->s_flags = flags;
 510         rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY);
 511         if (rc)
 512                 goto out1;
 513
 514         ecryptfs_set_superblock_private(s, sbi);
 515         s->s_bdi = &sbi->bdi;
 516
 517         /* ->kill_sb() will take care of sbi after that point */
 518         sbi = NULL;
 519         s->s_op = &ecryptfs_sops;
 520         s->s_d_op = &ecryptfs_dops;
 521
 522         err = "Reading sb failed";
 523         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 524         if (rc) {
 525                 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
 526                 goto out1;
 527         }
 528         if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
 529                 rc = -EINVAL;
 530                 printk(KERN_ERR "Mount on filesystem of type "
 531                         "eCryptfs explicitly disallowed due to "
 532                         "known incompatibilities\n");
 533                 goto out_free;
 534         }
 535
 536         if (check_ruid && path.dentry->d_inode->i_uid != current_uid()) {
 537                 rc = -EPERM;
 538                 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
 539                        "requested user (uid: %d)\n",
 540                        path.dentry->d_inode->i_uid, current_uid());
 541                 goto out_free;
 542         }
 543
 544         ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
 545         s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 546         s->s_blocksize = path.dentry->d_sb->s_blocksize;
 547         s->s_magic = ECRYPTFS_SUPER_MAGIC;
 548
 549         inode = ecryptfs_get_inode(path.dentry->d_inode, s);
 550         rc = PTR_ERR(inode);
 551         if (IS_ERR(inode))
 552                 goto out_free;
 553
 554         s->s_root = d_alloc_root(inode);
 555         if (!s->s_root) {
 556                 iput(inode);
 557                 rc = -ENOMEM;
 558                 goto out_free;
 559         }
 560
 561         rc = -ENOMEM;
 562         root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 563         if (!root_info)
 564                 goto out_free;
 565
 566         /* ->kill_sb() will take care of root_info */
 567         ecryptfs_set_dentry_private(s->s_root, root_info);
 568         ecryptfs_set_dentry_lower(s->s_root, path.dentry);
 569         ecryptfs_set_dentry_lower_mnt(s->s_root, path.mnt);
 570
 571         s->s_flags |= MS_ACTIVE;
 572         return dget(s->s_root);
 573
 574 out_free:
 575         path_put(&path);
 576 out1:
 577         deactivate_locked_super(s);
 578 out:
 579         if (sbi) {
 580                 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
 581                 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
 582         }
 583         printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
 584         return ERR_PTR(rc);
 585 }
 586
 587 /**
 588  * ecryptfs_kill_block_super
 589  * @sb: The ecryptfs super block
 590  *
 591  * Used to bring the superblock down and free the private data.
 592  */
 593 static void ecryptfs_kill_block_super(struct super_block *sb)
 594 {
 595         struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
 596         kill_anon_super(sb);
 597         if (!sb_info)
 598                 return;
 599         ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
 600         bdi_destroy(&sb_info->bdi);
 601         kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
 602 }
 603
 604 static struct file_system_type ecryptfs_fs_type = {
 605         .owner = THIS_MODULE,
 606         .name = "ecryptfs",
 607         .mount = ecryptfs_mount,
 608         .kill_sb = ecryptfs_kill_block_super,
 609         .fs_flags = 0
 610 };
 611
 612 /**
 613  * inode_info_init_once
 614  *
 615  * Initializes the ecryptfs_inode_info_cache when it is created
 616  */
 617 static void
 618 inode_info_init_once(void *vptr)
 619 {
 620         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 621
 622         inode_init_once(&ei->vfs_inode);
 623 }
 624
 625 static struct ecryptfs_cache_info {
 626         struct kmem_cache **cache;
 627         const char *name;
 628         size_t size;
 629         void (*ctor)(void *obj);
 630 } ecryptfs_cache_infos[] = {
 631         {
 632                 .cache = &ecryptfs_auth_tok_list_item_cache,
 633                 .name = "ecryptfs_auth_tok_list_item",
 634                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 635         },
 636         {
 637                 .cache = &ecryptfs_file_info_cache,
 638                 .name = "ecryptfs_file_cache",
 639                 .size = sizeof(struct ecryptfs_file_info),
 640         },
 641         {
 642                 .cache = &ecryptfs_dentry_info_cache,
 643                 .name = "ecryptfs_dentry_info_cache",
 644                 .size = sizeof(struct ecryptfs_dentry_info),
 645         },
 646         {
 647                 .cache = &ecryptfs_inode_info_cache,
 648                 .name = "ecryptfs_inode_cache",
 649                 .size = sizeof(struct ecryptfs_inode_info),
 650                 .ctor = inode_info_init_once,
 651         },
 652         {
 653                 .cache = &ecryptfs_sb_info_cache,
 654                 .name = "ecryptfs_sb_cache",
 655                 .size = sizeof(struct ecryptfs_sb_info),
 656         },
 657         {
 658                 .cache = &ecryptfs_header_cache,
 659                 .name = "ecryptfs_headers",
 660                 .size = PAGE_CACHE_SIZE,
 661         },
 662         {
 663                 .cache = &ecryptfs_xattr_cache,
 664                 .name = "ecryptfs_xattr_cache",
 665                 .size = PAGE_CACHE_SIZE,
 666         },
 667         {
 668                 .cache = &ecryptfs_key_record_cache,
 669                 .name = "ecryptfs_key_record_cache",
 670                 .size = sizeof(struct ecryptfs_key_record),
 671         },
 672         {
 673                 .cache = &ecryptfs_key_sig_cache,
 674                 .name = "ecryptfs_key_sig_cache",
 675                 .size = sizeof(struct ecryptfs_key_sig),
 676         },
 677         {
 678                 .cache = &ecryptfs_global_auth_tok_cache,
 679                 .name = "ecryptfs_global_auth_tok_cache",
 680                 .size = sizeof(struct ecryptfs_global_auth_tok),
 681         },
 682         {
 683                 .cache = &ecryptfs_key_tfm_cache,
 684                 .name = "ecryptfs_key_tfm_cache",
 685                 .size = sizeof(struct ecryptfs_key_tfm),
 686         },
 687         {
 688                 .cache = &ecryptfs_open_req_cache,
 689                 .name = "ecryptfs_open_req_cache",
 690                 .size = sizeof(struct ecryptfs_open_req),
 691         },
 692 };
 693
 694 static void ecryptfs_free_kmem_caches(void)
 695 {
 696         int i;
 697
 698         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 699                 struct ecryptfs_cache_info *info;
 700
 701                 info = &ecryptfs_cache_infos[i];
 702                 if (*(info->cache))
 703                         kmem_cache_destroy(*(info->cache));
 704         }
 705 }
 706
 707 /**
 708  * ecryptfs_init_kmem_caches
 709  *
 710  * Returns zero on success; non-zero otherwise
 711  */
 712 static int ecryptfs_init_kmem_caches(void)
 713 {
 714         int i;
 715
 716         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 717                 struct ecryptfs_cache_info *info;
 718
 719                 info = &ecryptfs_cache_infos[i];
 720                 *(info->cache) = kmem_cache_create(info->name, info->size,
 721                                 0, SLAB_HWCACHE_ALIGN, info->ctor);
 722                 if (!*(info->cache)) {
 723                         ecryptfs_free_kmem_caches();
 724                         ecryptfs_printk(KERN_WARNING, "%s: "
 725                                         "kmem_cache_create failed\n",
 726                                         info->name);
 727                         return -ENOMEM;
 728                 }
 729         }
 730         return 0;
 731 }
 732
 733 static struct kobject *ecryptfs_kobj;
 734
 735 static ssize_t version_show(struct kobject *kobj,
 736                             struct kobj_attribute *attr, char *buff)
 737 {
 738         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 739 }
 740
 741 static struct kobj_attribute version_attr = __ATTR_RO(version);
 742
 743 static struct attribute *attributes[] = {
 744         &version_attr.attr,
 745         NULL,
 746 };
 747
 748 static struct attribute_group attr_group = {
 749         .attrs = attributes,
 750 };
 751
 752 static int do_sysfs_registration(void)
 753 {
 754         int rc;
 755
 756         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 757         if (!ecryptfs_kobj) {
 758                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
 759                 rc = -ENOMEM;
 760                 goto out;
 761         }
 762         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 763         if (rc) {
 764                 printk(KERN_ERR
 765                        "Unable to create ecryptfs version attributes\n");
 766                 kobject_put(ecryptfs_kobj);
 767         }
 768 out:
 769         return rc;
 770 }
 771
 772 static void do_sysfs_unregistration(void)
 773 {
 774         sysfs_remove_group(ecryptfs_kobj, &attr_group);
 775         kobject_put(ecryptfs_kobj);
 776 }
 777
 778 static int __init ecryptfs_init(void)
 779 {
 780         int rc;
 781
 782         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
 783                 rc = -EINVAL;
 784                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 785                                 "larger than the host's page size, and so "
 786                                 "eCryptfs cannot run on this system. The "
 787                                 "default eCryptfs extent size is [%u] bytes; "
 788                                 "the page size is [%lu] bytes.\n",
 789                                 ECRYPTFS_DEFAULT_EXTENT_SIZE,
 790                                 (unsigned long)PAGE_CACHE_SIZE);
 791                 goto out;
 792         }
 793         rc = ecryptfs_init_kmem_caches();
 794         if (rc) {
 795                 printk(KERN_ERR
 796                        "Failed to allocate one or more kmem_cache objects\n");
 797                 goto out;
 798         }
 799         rc = register_filesystem(&ecryptfs_fs_type);
 800         if (rc) {
 801                 printk(KERN_ERR "Failed to register filesystem\n");
 802                 goto out_free_kmem_caches;
 803         }
 804         rc = do_sysfs_registration();
 805         if (rc) {
 806                 printk(KERN_ERR "sysfs registration failed\n");
 807                 goto out_unregister_filesystem;
 808         }
 809         rc = ecryptfs_init_kthread();
 810         if (rc) {
 811                 printk(KERN_ERR "%s: kthread initialization failed; "
 812                        "rc = [%d]\n", __func__, rc);
 813                 goto out_do_sysfs_unregistration;
 814         }
 815         rc = ecryptfs_init_messaging();
 816         if (rc) {
 817                 printk(KERN_ERR "Failure occurred while attempting to "
 818                                 "initialize the communications channel to "
 819                                 "ecryptfsd\n");
 820                 goto out_destroy_kthread;
 821         }
 822         rc = ecryptfs_init_crypto();
 823         if (rc) {
 824                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
 825                        "rc = [%d]\n", rc);
 826                 goto out_release_messaging;
 827         }
 828         if (ecryptfs_verbosity > 0)
 829                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 830                         "will be written to the syslog!\n", ecryptfs_verbosity);
 831
 832         goto out;
 833 out_release_messaging:
 834         ecryptfs_release_messaging();
 835 out_destroy_kthread:
 836         ecryptfs_destroy_kthread();
 837 out_do_sysfs_unregistration:
 838         do_sysfs_unregistration();
 839 out_unregister_filesystem:
 840         unregister_filesystem(&ecryptfs_fs_type);
 841 out_free_kmem_caches:
 842         ecryptfs_free_kmem_caches();
 843 out:
 844         return rc;
 845 }
 846
 847 static void __exit ecryptfs_exit(void)
 848 {
 849         int rc;
 850
 851         rc = ecryptfs_destroy_crypto();
 852         if (rc)
 853                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 854                        "rc = [%d]\n", rc);
 855         ecryptfs_release_messaging();
 856         ecryptfs_destroy_kthread();
 857         do_sysfs_unregistration();
 858         unregister_filesystem(&ecryptfs_fs_type);
 859         ecryptfs_free_kmem_caches();
 860 }
 861
 862 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 863 MODULE_DESCRIPTION("eCryptfs");
 864
 865 MODULE_LICENSE("GPL");
 866
 867 module_init(ecryptfs_init)
 868 module_exit(ecryptfs_exit)