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/mount.h>
  33 #include <linux/pagemap.h>
  34 #include <linux/key.h>
  35 #include <linux/parser.h>
  36 #include <linux/fs_stack.h>
  37 #include <linux/slab.h>
  38 #include <linux/magic.h>
  39 #include "ecryptfs_kernel.h"
  40
  41 /**
  42  * Module parameter that defines the ecryptfs_verbosity level.
  43  */
  44 int ecryptfs_verbosity = 0;
  45
  46 module_param(ecryptfs_verbosity, int, 0);
  47 MODULE_PARM_DESC(ecryptfs_verbosity,
  48                  "Initial verbosity level (0 or 1; defaults to "
  49                  "0, which is Quiet)");
  50
  51 /**
  52  * Module parameter that defines the number of message buffer elements
  53  */
  54 unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
  55
  56 module_param(ecryptfs_message_buf_len, uint, 0);
  57 MODULE_PARM_DESC(ecryptfs_message_buf_len,
  58                  "Number of message buffer elements");
  59
  60 /**
  61  * Module parameter that defines the maximum guaranteed amount of time to wait
  62  * for a response from ecryptfsd.  The actual sleep time will be, more than
  63  * likely, a small amount greater than this specified value, but only less if
  64  * the message successfully arrives.
  65  */
  66 signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
  67
  68 module_param(ecryptfs_message_wait_timeout, long, 0);
  69 MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
  70                  "Maximum number of seconds that an operation will "
  71                  "sleep while waiting for a message response from "
  72                  "userspace");
  73
  74 /**
  75  * Module parameter that is an estimate of the maximum number of users
  76  * that will be concurrently using eCryptfs. Set this to the right
  77  * value to balance performance and memory use.
  78  */
  79 unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
  80
  81 module_param(ecryptfs_number_of_users, uint, 0);
  82 MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
  83                  "concurrent users of eCryptfs");
  84
  85 void __ecryptfs_printk(const char *fmt, ...)
  86 {
  87         va_list args;
  88         va_start(args, fmt);
  89         if (fmt[1] == '7') { /* KERN_DEBUG */
  90                 if (ecryptfs_verbosity >= 1)
  91                         vprintk(fmt, args);
  92         } else
  93                 vprintk(fmt, args);
  94         va_end(args);
  95 }
  96
  97 /**
  98  * ecryptfs_init_lower_file
  99  * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
 100  *                   the lower dentry and the lower mount set
 101  *
 102  * eCryptfs only ever keeps a single open file for every lower
 103  * inode. All I/O operations to the lower inode occur through that
 104  * file. When the first eCryptfs dentry that interposes with the first
 105  * lower dentry for that inode is created, this function creates the
 106  * lower file struct and associates it with the eCryptfs
 107  * inode. When all eCryptfs files associated with the inode are released, the
 108  * file is closed.
 109  *
 110  * The lower file will be opened with read/write permissions, if
 111  * possible. Otherwise, it is opened read-only.
 112  *
 113  * This function does nothing if a lower file is already
 114  * associated with the eCryptfs inode.
 115  *
 116  * Returns zero on success; non-zero otherwise
 117  */
 118 static int ecryptfs_init_lower_file(struct dentry *dentry,
 119                                     struct file **lower_file)
 120 {
 121         const struct cred *cred = current_cred();
 122         struct path *path = ecryptfs_dentry_to_lower_path(dentry);
 123         int rc;
 124
 125         rc = ecryptfs_privileged_open(lower_file, path->dentry, path->mnt,
 126                                       cred);
 127         if (rc) {
 128                 printk(KERN_ERR "Error opening lower file "
 129                        "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
 130                        "rc = [%d]\n", path->dentry, path->mnt, rc);
 131                 (*lower_file) = NULL;
 132         }
 133         return rc;
 134 }
 135
 136 int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
 137 {
 138         struct ecryptfs_inode_info *inode_info;
 139         int count, rc = 0;
 140
 141         inode_info = ecryptfs_inode_to_private(inode);
 142         mutex_lock(&inode_info->lower_file_mutex);
 143         count = atomic_inc_return(&inode_info->lower_file_count);
 144         if (WARN_ON_ONCE(count < 1))
 145                 rc = -EINVAL;
 146         else if (count == 1) {
 147                 rc = ecryptfs_init_lower_file(dentry,
 148                                               &inode_info->lower_file);
 149                 if (rc)
 150                         atomic_set(&inode_info->lower_file_count, 0);
 151         }
 152         mutex_unlock(&inode_info->lower_file_mutex);
 153         return rc;
 154 }
 155
 156 void ecryptfs_put_lower_file(struct inode *inode)
 157 {
 158         struct ecryptfs_inode_info *inode_info;
 159
 160         inode_info = ecryptfs_inode_to_private(inode);
 161         if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
 162                                       &inode_info->lower_file_mutex)) {
 163                 filemap_write_and_wait(inode->i_mapping);
 164                 fput(inode_info->lower_file);
 165                 inode_info->lower_file = NULL;
 166                 mutex_unlock(&inode_info->lower_file_mutex);
 167         }
 168 }
 169
 170 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
 171        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
 172        ecryptfs_opt_ecryptfs_key_bytes,
 173        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
 174        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
 175        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
 176        ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
 177        ecryptfs_opt_check_dev_ruid,
 178        ecryptfs_opt_err };
 179
 180 static const match_table_t tokens = {
 181         {ecryptfs_opt_sig, "sig=%s"},
 182         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 183         {ecryptfs_opt_cipher, "cipher=%s"},
 184         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
 185         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
 186         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
 187         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
 188         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
 189         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
 190         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
 191         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
 192         {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
 193         {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
 194         {ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
 195         {ecryptfs_opt_err, NULL}
 196 };
 197
 198 static int ecryptfs_init_global_auth_toks(
 199         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 200 {
 201         struct ecryptfs_global_auth_tok *global_auth_tok;
 202         struct ecryptfs_auth_tok *auth_tok;
 203         int rc = 0;
 204
 205         list_for_each_entry(global_auth_tok,
 206                             &mount_crypt_stat->global_auth_tok_list,
 207                             mount_crypt_stat_list) {
 208                 rc = ecryptfs_keyring_auth_tok_for_sig(
 209                         &global_auth_tok->global_auth_tok_key, &auth_tok,
 210                         global_auth_tok->sig);
 211                 if (rc) {
 212                         printk(KERN_ERR "Could not find valid key in user "
 213                                "session keyring for sig specified in mount "
 214                                "option: [%s]\n", global_auth_tok->sig);
 215                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 216                         goto out;
 217                 } else {
 218                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
 219                         up_write(&(global_auth_tok->global_auth_tok_key)->sem);
 220                 }
 221         }
 222 out:
 223         return rc;
 224 }
 225
 226 static void ecryptfs_init_mount_crypt_stat(
 227         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 228 {
 229         memset((void *)mount_crypt_stat, 0,
 230                sizeof(struct ecryptfs_mount_crypt_stat));
 231         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
 232         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
 233         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
 234 }
 235
 236 /**
 237  * ecryptfs_parse_options
 238  * @sb: The ecryptfs super block
 239  * @options: The options passed to the kernel
 240  * @check_ruid: set to 1 if device uid should be checked against the ruid
 241  *
 242  * Parse mount options:
 243  * debug=N         - ecryptfs_verbosity level for debug output
 244  * sig=XXX         - description(signature) of the key to use
 245  *
 246  * Returns the dentry object of the lower-level (lower/interposed)
 247  * directory; We want to mount our stackable file system on top of
 248  * that lower directory.
 249  *
 250  * The signature of the key to use must be the description of a key
 251  * already in the keyring. Mounting will fail if the key can not be
 252  * found.
 253  *
 254  * Returns zero on success; non-zero on error
 255  */
 256 static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
 257                                   uid_t *check_ruid)
 258 {
 259         char *p;
 260         int rc = 0;
 261         int sig_set = 0;
 262         int cipher_name_set = 0;
 263         int fn_cipher_name_set = 0;
 264         int cipher_key_bytes;
 265         int cipher_key_bytes_set = 0;
 266         int fn_cipher_key_bytes;
 267         int fn_cipher_key_bytes_set = 0;
 268         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 269                 &sbi->mount_crypt_stat;
 270         substring_t args[MAX_OPT_ARGS];
 271         int token;
 272         char *sig_src;
 273         char *cipher_name_dst;
 274         char *cipher_name_src;
 275         char *fn_cipher_name_dst;
 276         char *fn_cipher_name_src;
 277         char *fnek_dst;
 278         char *fnek_src;
 279         char *cipher_key_bytes_src;
 280         char *fn_cipher_key_bytes_src;
 281         u8 cipher_code;
 282
 283         *check_ruid = 0;
 284
 285         if (!options) {
 286                 rc = -EINVAL;
 287                 goto out;
 288         }
 289         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
 290         while ((p = strsep(&options, ",")) != NULL) {
 291                 if (!*p)
 292                         continue;
 293                 token = match_token(p, tokens, args);
 294                 switch (token) {
 295                 case ecryptfs_opt_sig:
 296                 case ecryptfs_opt_ecryptfs_sig:
 297                         sig_src = args[0].from;
 298                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
 299                                                           sig_src, 0);
 300                         if (rc) {
 301                                 printk(KERN_ERR "Error attempting to register "
 302                                        "global sig; rc = [%d]\n", rc);
 303                                 goto out;
 304                         }
 305                         sig_set = 1;
 306                         break;
 307                 case ecryptfs_opt_cipher:
 308                 case ecryptfs_opt_ecryptfs_cipher:
 309                         cipher_name_src = args[0].from;
 310                         cipher_name_dst =
 311                                 mount_crypt_stat->
 312                                 global_default_cipher_name;
 313                         strncpy(cipher_name_dst, cipher_name_src,
 314                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 315                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 316                         cipher_name_set = 1;
 317                         break;
 318                 case ecryptfs_opt_ecryptfs_key_bytes:
 319                         cipher_key_bytes_src = args[0].from;
 320                         cipher_key_bytes =
 321                                 (int)simple_strtol(cipher_key_bytes_src,
 322                                                    &cipher_key_bytes_src, 0);
 323                         mount_crypt_stat->global_default_cipher_key_size =
 324                                 cipher_key_bytes;
 325                         cipher_key_bytes_set = 1;
 326                         break;
 327                 case ecryptfs_opt_passthrough:
 328                         mount_crypt_stat->flags |=
 329                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 330                         break;
 331                 case ecryptfs_opt_xattr_metadata:
 332                         mount_crypt_stat->flags |=
 333                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 334                         break;
 335                 case ecryptfs_opt_encrypted_view:
 336                         mount_crypt_stat->flags |=
 337                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 338                         mount_crypt_stat->flags |=
 339                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 340                         break;
 341                 case ecryptfs_opt_fnek_sig:
 342                         fnek_src = args[0].from;
 343                         fnek_dst =
 344                                 mount_crypt_stat->global_default_fnek_sig;
 345                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
 346                         mount_crypt_stat->global_default_fnek_sig[
 347                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
 348                         rc = ecryptfs_add_global_auth_tok(
 349                                 mount_crypt_stat,
 350                                 mount_crypt_stat->global_default_fnek_sig,
 351                                 ECRYPTFS_AUTH_TOK_FNEK);
 352                         if (rc) {
 353                                 printk(KERN_ERR "Error attempting to register "
 354                                        "global fnek sig [%s]; rc = [%d]\n",
 355                                        mount_crypt_stat->global_default_fnek_sig,
 356                                        rc);
 357                                 goto out;
 358                         }
 359                         mount_crypt_stat->flags |=
 360                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 361                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 362                         break;
 363                 case ecryptfs_opt_fn_cipher:
 364                         fn_cipher_name_src = args[0].from;
 365                         fn_cipher_name_dst =
 366                                 mount_crypt_stat->global_default_fn_cipher_name;
 367                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
 368                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 369                         mount_crypt_stat->global_default_fn_cipher_name[
 370                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 371                         fn_cipher_name_set = 1;
 372                         break;
 373                 case ecryptfs_opt_fn_cipher_key_bytes:
 374                         fn_cipher_key_bytes_src = args[0].from;
 375                         fn_cipher_key_bytes =
 376                                 (int)simple_strtol(fn_cipher_key_bytes_src,
 377                                                    &fn_cipher_key_bytes_src, 0);
 378                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
 379                                 fn_cipher_key_bytes;
 380                         fn_cipher_key_bytes_set = 1;
 381                         break;
 382                 case ecryptfs_opt_unlink_sigs:
 383                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
 384                         break;
 385                 case ecryptfs_opt_mount_auth_tok_only:
 386                         mount_crypt_stat->flags |=
 387                                 ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
 388                         break;
 389                 case ecryptfs_opt_check_dev_ruid:
 390                         *check_ruid = 1;
 391                         break;
 392                 case ecryptfs_opt_err:
 393                 default:
 394                         printk(KERN_WARNING
 395                                "%s: eCryptfs: unrecognized option [%s]\n",
 396                                __func__, p);
 397                 }
 398         }
 399         if (!sig_set) {
 400                 rc = -EINVAL;
 401                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
 402                                 "auth tok signature as a mount "
 403                                 "parameter; see the eCryptfs README\n");
 404                 goto out;
 405         }
 406         if (!cipher_name_set) {
 407                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 408
 409                 BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 410                 strcpy(mount_crypt_stat->global_default_cipher_name,
 411                        ECRYPTFS_DEFAULT_CIPHER);
 412         }
 413         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 414             && !fn_cipher_name_set)
 415                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
 416                        mount_crypt_stat->global_default_cipher_name);
 417         if (!cipher_key_bytes_set)
 418                 mount_crypt_stat->global_default_cipher_key_size = 0;
 419         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 420             && !fn_cipher_key_bytes_set)
 421                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
 422                         mount_crypt_stat->global_default_cipher_key_size;
 423
 424         cipher_code = ecryptfs_code_for_cipher_string(
 425                 mount_crypt_stat->global_default_cipher_name,
 426                 mount_crypt_stat->global_default_cipher_key_size);
 427         if (!cipher_code) {
 428                 ecryptfs_printk(KERN_ERR,
 429                                 "eCryptfs doesn't support cipher: %s\n",
 430                                 mount_crypt_stat->global_default_cipher_name);
 431                 rc = -EINVAL;
 432                 goto out;
 433         }
 434
 435         mutex_lock(&key_tfm_list_mutex);
 436         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
 437                                  NULL)) {
 438                 rc = ecryptfs_add_new_key_tfm(
 439                         NULL, mount_crypt_stat->global_default_cipher_name,
 440                         mount_crypt_stat->global_default_cipher_key_size);
 441                 if (rc) {
 442                         printk(KERN_ERR "Error attempting to initialize "
 443                                "cipher with name = [%s] and key size = [%td]; "
 444                                "rc = [%d]\n",
 445                                mount_crypt_stat->global_default_cipher_name,
 446                                mount_crypt_stat->global_default_cipher_key_size,
 447                                rc);
 448                         rc = -EINVAL;
 449                         mutex_unlock(&key_tfm_list_mutex);
 450                         goto out;
 451                 }
 452         }
 453         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 454             && !ecryptfs_tfm_exists(
 455                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
 456                 rc = ecryptfs_add_new_key_tfm(
 457                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
 458                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
 459                 if (rc) {
 460                         printk(KERN_ERR "Error attempting to initialize "
 461                                "cipher with name = [%s] and key size = [%td]; "
 462                                "rc = [%d]\n",
 463                                mount_crypt_stat->global_default_fn_cipher_name,
 464                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
 465                                rc);
 466                         rc = -EINVAL;
 467                         mutex_unlock(&key_tfm_list_mutex);
 468                         goto out;
 469                 }
 470         }
 471         mutex_unlock(&key_tfm_list_mutex);
 472         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
 473         if (rc)
 474                 printk(KERN_WARNING "One or more global auth toks could not "
 475                        "properly register; rc = [%d]\n", rc);
 476 out:
 477         return rc;
 478 }
 479
 480 struct kmem_cache *ecryptfs_sb_info_cache;
 481 static struct file_system_type ecryptfs_fs_type;
 482
 483 /**
 484  * ecryptfs_get_sb
 485  * @fs_type
 486  * @flags
 487  * @dev_name: The path to mount over
 488  * @raw_data: The options passed into the kernel
 489  */
 490 static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
 491                         const char *dev_name, void *raw_data)
 492 {
 493         struct super_block *s;
 494         struct ecryptfs_sb_info *sbi;
 495         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 496         struct ecryptfs_dentry_info *root_info;
 497         const char *err = "Getting sb failed";
 498         struct inode *inode;
 499         struct path path;
 500         uid_t check_ruid;
 501         int rc;
 502
 503         sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
 504         if (!sbi) {
 505                 rc = -ENOMEM;
 506                 goto out;
 507         }
 508
 509         rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
 510         if (rc) {
 511                 err = "Error parsing options";
 512                 goto out;
 513         }
 514         mount_crypt_stat = &sbi->mount_crypt_stat;
 515
 516         s = sget(fs_type, NULL, set_anon_super, flags, NULL);
 517         if (IS_ERR(s)) {
 518                 rc = PTR_ERR(s);
 519                 goto out;
 520         }
 521
 522         rc = super_setup_bdi(s);
 523         if (rc)
 524                 goto out1;
 525
 526         ecryptfs_set_superblock_private(s, sbi);
 527
 528         /* ->kill_sb() will take care of sbi after that point */
 529         sbi = NULL;
 530         s->s_op = &ecryptfs_sops;
 531         s->s_xattr = ecryptfs_xattr_handlers;
 532         s->s_d_op = &ecryptfs_dops;
 533
 534         err = "Reading sb failed";
 535         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 536         if (rc) {
 537                 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
 538                 goto out1;
 539         }
 540         if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
 541                 rc = -EINVAL;
 542                 printk(KERN_ERR "Mount on filesystem of type "
 543                         "eCryptfs explicitly disallowed due to "
 544                         "known incompatibilities\n");
 545                 goto out_free;
 546         }
 547
 548         if (check_ruid && !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) {
 549                 rc = -EPERM;
 550                 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
 551                        "requested user (uid: %d)\n",
 552                         i_uid_read(d_inode(path.dentry)),
 553                         from_kuid(&init_user_ns, current_uid()));
 554                 goto out_free;
 555         }
 556
 557         ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
 558
 559         /**
 560          * Set the POSIX ACL flag based on whether they're enabled in the lower
 561          * mount.
 562          */
 563         s->s_flags = flags & ~MS_POSIXACL;
 564         s->s_flags |= path.dentry->d_sb->s_flags & MS_POSIXACL;
 565
 566         /**
 567          * Force a read-only eCryptfs mount when:
 568          *   1) The lower mount is ro
 569          *   2) The ecryptfs_encrypted_view mount option is specified
 570          */
 571         if (sb_rdonly(path.dentry->d_sb) || mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
 572                 s->s_flags |= MS_RDONLY;
 573
 574         s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 575         s->s_blocksize = path.dentry->d_sb->s_blocksize;
 576         s->s_magic = ECRYPTFS_SUPER_MAGIC;
 577         s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
 578
 579         rc = -EINVAL;
 580         if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
 581                 pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
 582                 goto out_free;
 583         }
 584
 585         inode = ecryptfs_get_inode(d_inode(path.dentry), s);
 586         rc = PTR_ERR(inode);
 587         if (IS_ERR(inode))
 588                 goto out_free;
 589
 590         s->s_root = d_make_root(inode);
 591         if (!s->s_root) {
 592                 rc = -ENOMEM;
 593                 goto out_free;
 594         }
 595
 596         rc = -ENOMEM;
 597         root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 598         if (!root_info)
 599                 goto out_free;
 600
 601         /* ->kill_sb() will take care of root_info */
 602         ecryptfs_set_dentry_private(s->s_root, root_info);
 603         root_info->lower_path = path;
 604
 605         s->s_flags |= MS_ACTIVE;
 606         return dget(s->s_root);
 607
 608 out_free:
 609         path_put(&path);
 610 out1:
 611         deactivate_locked_super(s);
 612 out:
 613         if (sbi) {
 614                 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
 615                 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
 616         }
 617         printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
 618         return ERR_PTR(rc);
 619 }
 620
 621 /**
 622  * ecryptfs_kill_block_super
 623  * @sb: The ecryptfs super block
 624  *
 625  * Used to bring the superblock down and free the private data.
 626  */
 627 static void ecryptfs_kill_block_super(struct super_block *sb)
 628 {
 629         struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
 630         kill_anon_super(sb);
 631         if (!sb_info)
 632                 return;
 633         ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
 634         kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
 635 }
 636
 637 static struct file_system_type ecryptfs_fs_type = {
 638         .owner = THIS_MODULE,
 639         .name = "ecryptfs",
 640         .mount = ecryptfs_mount,
 641         .kill_sb = ecryptfs_kill_block_super,
 642         .fs_flags = 0
 643 };
 644 MODULE_ALIAS_FS("ecryptfs");
 645
 646 /**
 647  * inode_info_init_once
 648  *
 649  * Initializes the ecryptfs_inode_info_cache when it is created
 650  */
 651 static void
 652 inode_info_init_once(void *vptr)
 653 {
 654         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 655
 656         inode_init_once(&ei->vfs_inode);
 657 }
 658
 659 static struct ecryptfs_cache_info {
 660         struct kmem_cache **cache;
 661         const char *name;
 662         size_t size;
 663         slab_flags_t flags;
 664         void (*ctor)(void *obj);
 665 } ecryptfs_cache_infos[] = {
 666         {
 667                 .cache = &ecryptfs_auth_tok_list_item_cache,
 668                 .name = "ecryptfs_auth_tok_list_item",
 669                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 670         },
 671         {
 672                 .cache = &ecryptfs_file_info_cache,
 673                 .name = "ecryptfs_file_cache",
 674                 .size = sizeof(struct ecryptfs_file_info),
 675         },
 676         {
 677                 .cache = &ecryptfs_dentry_info_cache,
 678                 .name = "ecryptfs_dentry_info_cache",
 679                 .size = sizeof(struct ecryptfs_dentry_info),
 680         },
 681         {
 682                 .cache = &ecryptfs_inode_info_cache,
 683                 .name = "ecryptfs_inode_cache",
 684                 .size = sizeof(struct ecryptfs_inode_info),
 685                 .flags = SLAB_ACCOUNT,
 686                 .ctor = inode_info_init_once,
 687         },
 688         {
 689                 .cache = &ecryptfs_sb_info_cache,
 690                 .name = "ecryptfs_sb_cache",
 691                 .size = sizeof(struct ecryptfs_sb_info),
 692         },
 693         {
 694                 .cache = &ecryptfs_header_cache,
 695                 .name = "ecryptfs_headers",
 696                 .size = PAGE_SIZE,
 697         },
 698         {
 699                 .cache = &ecryptfs_xattr_cache,
 700                 .name = "ecryptfs_xattr_cache",
 701                 .size = PAGE_SIZE,
 702         },
 703         {
 704                 .cache = &ecryptfs_key_record_cache,
 705                 .name = "ecryptfs_key_record_cache",
 706                 .size = sizeof(struct ecryptfs_key_record),
 707         },
 708         {
 709                 .cache = &ecryptfs_key_sig_cache,
 710                 .name = "ecryptfs_key_sig_cache",
 711                 .size = sizeof(struct ecryptfs_key_sig),
 712         },
 713         {
 714                 .cache = &ecryptfs_global_auth_tok_cache,
 715                 .name = "ecryptfs_global_auth_tok_cache",
 716                 .size = sizeof(struct ecryptfs_global_auth_tok),
 717         },
 718         {
 719                 .cache = &ecryptfs_key_tfm_cache,
 720                 .name = "ecryptfs_key_tfm_cache",
 721                 .size = sizeof(struct ecryptfs_key_tfm),
 722         },
 723 };
 724
 725 static void ecryptfs_free_kmem_caches(void)
 726 {
 727         int i;
 728
 729         /*
 730          * Make sure all delayed rcu free inodes are flushed before we
 731          * destroy cache.
 732          */
 733         rcu_barrier();
 734
 735         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 736                 struct ecryptfs_cache_info *info;
 737
 738                 info = &ecryptfs_cache_infos[i];
 739                 kmem_cache_destroy(*(info->cache));
 740         }
 741 }
 742
 743 /**
 744  * ecryptfs_init_kmem_caches
 745  *
 746  * Returns zero on success; non-zero otherwise
 747  */
 748 static int ecryptfs_init_kmem_caches(void)
 749 {
 750         int i;
 751
 752         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 753                 struct ecryptfs_cache_info *info;
 754
 755                 info = &ecryptfs_cache_infos[i];
 756                 *(info->cache) = kmem_cache_create(info->name, info->size, 0,
 757                                 SLAB_HWCACHE_ALIGN | info->flags, info->ctor);
 758                 if (!*(info->cache)) {
 759                         ecryptfs_free_kmem_caches();
 760                         ecryptfs_printk(KERN_WARNING, "%s: "
 761                                         "kmem_cache_create failed\n",
 762                                         info->name);
 763                         return -ENOMEM;
 764                 }
 765         }
 766         return 0;
 767 }
 768
 769 static struct kobject *ecryptfs_kobj;
 770
 771 static ssize_t version_show(struct kobject *kobj,
 772                             struct kobj_attribute *attr, char *buff)
 773 {
 774         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 775 }
 776
 777 static struct kobj_attribute version_attr = __ATTR_RO(version);
 778
 779 static struct attribute *attributes[] = {
 780         &version_attr.attr,
 781         NULL,
 782 };
 783
 784 static const struct attribute_group attr_group = {
 785         .attrs = attributes,
 786 };
 787
 788 static int do_sysfs_registration(void)
 789 {
 790         int rc;
 791
 792         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 793         if (!ecryptfs_kobj) {
 794                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
 795                 rc = -ENOMEM;
 796                 goto out;
 797         }
 798         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 799         if (rc) {
 800                 printk(KERN_ERR
 801                        "Unable to create ecryptfs version attributes\n");
 802                 kobject_put(ecryptfs_kobj);
 803         }
 804 out:
 805         return rc;
 806 }
 807
 808 static void do_sysfs_unregistration(void)
 809 {
 810         sysfs_remove_group(ecryptfs_kobj, &attr_group);
 811         kobject_put(ecryptfs_kobj);
 812 }
 813
 814 static int __init ecryptfs_init(void)
 815 {
 816         int rc;
 817
 818         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_SIZE) {
 819                 rc = -EINVAL;
 820                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 821                                 "larger than the host's page size, and so "
 822                                 "eCryptfs cannot run on this system. The "
 823                                 "default eCryptfs extent size is [%u] bytes; "
 824                                 "the page size is [%lu] bytes.\n",
 825                                 ECRYPTFS_DEFAULT_EXTENT_SIZE,
 826                                 (unsigned long)PAGE_SIZE);
 827                 goto out;
 828         }
 829         rc = ecryptfs_init_kmem_caches();
 830         if (rc) {
 831                 printk(KERN_ERR
 832                        "Failed to allocate one or more kmem_cache objects\n");
 833                 goto out;
 834         }
 835         rc = do_sysfs_registration();
 836         if (rc) {
 837                 printk(KERN_ERR "sysfs registration failed\n");
 838                 goto out_free_kmem_caches;
 839         }
 840         rc = ecryptfs_init_kthread();
 841         if (rc) {
 842                 printk(KERN_ERR "%s: kthread initialization failed; "
 843                        "rc = [%d]\n", __func__, rc);
 844                 goto out_do_sysfs_unregistration;
 845         }
 846         rc = ecryptfs_init_messaging();
 847         if (rc) {
 848                 printk(KERN_ERR "Failure occurred while attempting to "
 849                                 "initialize the communications channel to "
 850                                 "ecryptfsd\n");
 851                 goto out_destroy_kthread;
 852         }
 853         rc = ecryptfs_init_crypto();
 854         if (rc) {
 855                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
 856                        "rc = [%d]\n", rc);
 857                 goto out_release_messaging;
 858         }
 859         rc = register_filesystem(&ecryptfs_fs_type);
 860         if (rc) {
 861                 printk(KERN_ERR "Failed to register filesystem\n");
 862                 goto out_destroy_crypto;
 863         }
 864         if (ecryptfs_verbosity > 0)
 865                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 866                         "will be written to the syslog!\n", ecryptfs_verbosity);
 867
 868         goto out;
 869 out_destroy_crypto:
 870         ecryptfs_destroy_crypto();
 871 out_release_messaging:
 872         ecryptfs_release_messaging();
 873 out_destroy_kthread:
 874         ecryptfs_destroy_kthread();
 875 out_do_sysfs_unregistration:
 876         do_sysfs_unregistration();
 877 out_free_kmem_caches:
 878         ecryptfs_free_kmem_caches();
 879 out:
 880         return rc;
 881 }
 882
 883 static void __exit ecryptfs_exit(void)
 884 {
 885         int rc;
 886
 887         rc = ecryptfs_destroy_crypto();
 888         if (rc)
 889                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 890                        "rc = [%d]\n", rc);
 891         ecryptfs_release_messaging();
 892         ecryptfs_destroy_kthread();
 893         do_sysfs_unregistration();
 894         unregister_filesystem(&ecryptfs_fs_type);
 895         ecryptfs_free_kmem_caches();
 896 }
 897
 898 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 899 MODULE_DESCRIPTION("eCryptfs");
 900
 901 MODULE_LICENSE("GPL");
 902
 903 module_init(ecryptfs_init)
 904 module_exit(ecryptfs_exit)