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 || IS_ERR(inode_info->lower_file)) {
 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                         rc = PTR_ERR(inode_info->lower_file);
 137                         inode_info->lower_file = NULL;
 138                 }
 139         }
 140         mutex_unlock(&inode_info->lower_file_mutex);
 141         return rc;
 142 }
 143
 144 /**
 145  * ecryptfs_interpose
 146  * @lower_dentry: Existing dentry in the lower filesystem
 147  * @dentry: ecryptfs' dentry
 148  * @sb: ecryptfs's super_block
 149  * @flags: flags to govern behavior of interpose procedure
 150  *
 151  * Interposes upper and lower dentries.
 152  *
 153  * Returns zero on success; non-zero otherwise
 154  */
 155 int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
 156                        struct super_block *sb, u32 flags)
 157 {
 158         struct inode *lower_inode;
 159         struct inode *inode;
 160         int rc = 0;
 161
 162         lower_inode = lower_dentry->d_inode;
 163         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) {
 164                 rc = -EXDEV;
 165                 goto out;
 166         }
 167         if (!igrab(lower_inode)) {
 168                 rc = -ESTALE;
 169                 goto out;
 170         }
 171         inode = iget5_locked(sb, (unsigned long)lower_inode,
 172                              ecryptfs_inode_test, ecryptfs_inode_set,
 173                              lower_inode);
 174         if (!inode) {
 175                 rc = -EACCES;
 176                 iput(lower_inode);
 177                 goto out;
 178         }
 179         if (inode->i_state & I_NEW)
 180                 unlock_new_inode(inode);
 181         else
 182                 iput(lower_inode);
 183         if (S_ISLNK(lower_inode->i_mode))
 184                 inode->i_op = &ecryptfs_symlink_iops;
 185         else if (S_ISDIR(lower_inode->i_mode))
 186                 inode->i_op = &ecryptfs_dir_iops;
 187         if (S_ISDIR(lower_inode->i_mode))
 188                 inode->i_fop = &ecryptfs_dir_fops;
 189         if (special_file(lower_inode->i_mode))
 190                 init_special_inode(inode, lower_inode->i_mode,
 191                                    lower_inode->i_rdev);
 192         dentry->d_op = &ecryptfs_dops;
 193         if (flags & ECRYPTFS_INTERPOSE_FLAG_D_ADD)
 194                 d_add(dentry, inode);
 195         else
 196                 d_instantiate(dentry, inode);
 197         fsstack_copy_attr_all(inode, lower_inode, NULL);
 198         /* This size will be overwritten for real files w/ headers and
 199          * other metadata */
 200         fsstack_copy_inode_size(inode, lower_inode);
 201 out:
 202         return rc;
 203 }
 204
 205 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
 206        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
 207        ecryptfs_opt_ecryptfs_key_bytes,
 208        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
 209        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
 210        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
 211        ecryptfs_opt_err };
 212
 213 static const match_table_t tokens = {
 214         {ecryptfs_opt_sig, "sig=%s"},
 215         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 216         {ecryptfs_opt_cipher, "cipher=%s"},
 217         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
 218         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
 219         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
 220         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
 221         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
 222         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
 223         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
 224         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
 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);
 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                         if (rc) {
 375                                 printk(KERN_ERR "Error attempting to register "
 376                                        "global fnek sig [%s]; rc = [%d]\n",
 377                                        mount_crypt_stat->global_default_fnek_sig,
 378                                        rc);
 379                                 goto out;
 380                         }
 381                         mount_crypt_stat->flags |=
 382                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 383                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 384                         break;
 385                 case ecryptfs_opt_fn_cipher:
 386                         fn_cipher_name_src = args[0].from;
 387                         fn_cipher_name_dst =
 388                                 mount_crypt_stat->global_default_fn_cipher_name;
 389                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
 390                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 391                         mount_crypt_stat->global_default_fn_cipher_name[
 392                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 393                         fn_cipher_name_set = 1;
 394                         break;
 395                 case ecryptfs_opt_fn_cipher_key_bytes:
 396                         fn_cipher_key_bytes_src = args[0].from;
 397                         fn_cipher_key_bytes =
 398                                 (int)simple_strtol(fn_cipher_key_bytes_src,
 399                                                    &fn_cipher_key_bytes_src, 0);
 400                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
 401                                 fn_cipher_key_bytes;
 402                         fn_cipher_key_bytes_set = 1;
 403                         break;
 404                 case ecryptfs_opt_err:
 405                 default:
 406                         printk(KERN_WARNING
 407                                "%s: eCryptfs: unrecognized option [%s]\n",
 408                                __func__, p);
 409                 }
 410         }
 411         if (!sig_set) {
 412                 rc = -EINVAL;
 413                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
 414                                 "auth tok signature as a mount "
 415                                 "parameter; see the eCryptfs README\n");
 416                 goto out;
 417         }
 418         if (!cipher_name_set) {
 419                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 420
 421                 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 422                 strcpy(mount_crypt_stat->global_default_cipher_name,
 423                        ECRYPTFS_DEFAULT_CIPHER);
 424         }
 425         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 426             && !fn_cipher_name_set)
 427                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
 428                        mount_crypt_stat->global_default_cipher_name);
 429         if (!cipher_key_bytes_set)
 430                 mount_crypt_stat->global_default_cipher_key_size = 0;
 431         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 432             && !fn_cipher_key_bytes_set)
 433                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
 434                         mount_crypt_stat->global_default_cipher_key_size;
 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
 482 /**
 483  * ecryptfs_fill_super
 484  * @sb: The ecryptfs super block
 485  * @raw_data: The options passed to mount
 486  * @silent: Not used but required by function prototype
 487  *
 488  * Sets up what we can of the sb, rest is done in ecryptfs_read_super
 489  *
 490  * Returns zero on success; non-zero otherwise
 491  */
 492 static int
 493 ecryptfs_fill_super(struct super_block *sb, void *raw_data, int silent)
 494 {
 495         int rc = 0;
 496
 497         /* Released in ecryptfs_put_super() */
 498         ecryptfs_set_superblock_private(sb,
 499                                         kmem_cache_zalloc(ecryptfs_sb_info_cache,
 500                                                          GFP_KERNEL));
 501         if (!ecryptfs_superblock_to_private(sb)) {
 502                 ecryptfs_printk(KERN_WARNING, "Out of memory\n");
 503                 rc = -ENOMEM;
 504                 goto out;
 505         }
 506         sb->s_op = &ecryptfs_sops;
 507         /* Released through deactivate_super(sb) from get_sb_nodev */
 508         sb->s_root = d_alloc(NULL, &(const struct qstr) {
 509                              .hash = 0,.name = "/",.len = 1});
 510         if (!sb->s_root) {
 511                 ecryptfs_printk(KERN_ERR, "d_alloc failed\n");
 512                 rc = -ENOMEM;
 513                 goto out;
 514         }
 515         sb->s_root->d_op = &ecryptfs_dops;
 516         sb->s_root->d_sb = sb;
 517         sb->s_root->d_parent = sb->s_root;
 518         /* Released in d_release when dput(sb->s_root) is called */
 519         /* through deactivate_super(sb) from get_sb_nodev() */
 520         ecryptfs_set_dentry_private(sb->s_root,
 521                                     kmem_cache_zalloc(ecryptfs_dentry_info_cache,
 522                                                      GFP_KERNEL));
 523         if (!ecryptfs_dentry_to_private(sb->s_root)) {
 524                 ecryptfs_printk(KERN_ERR,
 525                                 "dentry_info_cache alloc failed\n");
 526                 rc = -ENOMEM;
 527                 goto out;
 528         }
 529         rc = 0;
 530 out:
 531         /* Should be able to rely on deactivate_super called from
 532          * get_sb_nodev */
 533         return rc;
 534 }
 535
 536 /**
 537  * ecryptfs_read_super
 538  * @sb: The ecryptfs super block
 539  * @dev_name: The path to mount over
 540  *
 541  * Read the super block of the lower filesystem, and use
 542  * ecryptfs_interpose to create our initial inode and super block
 543  * struct.
 544  */
 545 static int ecryptfs_read_super(struct super_block *sb, const char *dev_name)
 546 {
 547         struct path path;
 548         int rc;
 549
 550         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 551         if (rc) {
 552                 ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n");
 553                 goto out;
 554         }
 555         ecryptfs_set_superblock_lower(sb, path.dentry->d_sb);
 556         sb->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 557         sb->s_blocksize = path.dentry->d_sb->s_blocksize;
 558         ecryptfs_set_dentry_lower(sb->s_root, path.dentry);
 559         ecryptfs_set_dentry_lower_mnt(sb->s_root, path.mnt);
 560         rc = ecryptfs_interpose(path.dentry, sb->s_root, sb, 0);
 561         if (rc)
 562                 goto out_free;
 563         rc = 0;
 564         goto out;
 565 out_free:
 566         path_put(&path);
 567 out:
 568         return rc;
 569 }
 570
 571 /**
 572  * ecryptfs_get_sb
 573  * @fs_type
 574  * @flags
 575  * @dev_name: The path to mount over
 576  * @raw_data: The options passed into the kernel
 577  *
 578  * The whole ecryptfs_get_sb process is broken into 4 functions:
 579  * ecryptfs_parse_options(): handle options passed to ecryptfs, if any
 580  * ecryptfs_fill_super(): used by get_sb_nodev, fills out the super_block
 581  *                        with as much information as it can before needing
 582  *                        the lower filesystem.
 583  * ecryptfs_read_super(): this accesses the lower filesystem and uses
 584  *                        ecryptfs_interpolate to perform most of the linking
 585  * ecryptfs_interpolate(): links the lower filesystem into ecryptfs
 586  */
 587 static int ecryptfs_get_sb(struct file_system_type *fs_type, int flags,
 588                         const char *dev_name, void *raw_data,
 589                         struct vfsmount *mnt)
 590 {
 591         int rc;
 592         struct super_block *sb;
 593
 594         rc = get_sb_nodev(fs_type, flags, raw_data, ecryptfs_fill_super, mnt);
 595         if (rc < 0) {
 596                 printk(KERN_ERR "Getting sb failed; rc = [%d]\n", rc);
 597                 goto out;
 598         }
 599         sb = mnt->mnt_sb;
 600         rc = ecryptfs_parse_options(sb, raw_data);
 601         if (rc) {
 602                 printk(KERN_ERR "Error parsing options; rc = [%d]\n", rc);
 603                 goto out_abort;
 604         }
 605         rc = ecryptfs_read_super(sb, dev_name);
 606         if (rc) {
 607                 printk(KERN_ERR "Reading sb failed; rc = [%d]\n", rc);
 608                 goto out_abort;
 609         }
 610         goto out;
 611 out_abort:
 612         dput(sb->s_root);
 613         up_write(&sb->s_umount);
 614         deactivate_super(sb);
 615 out:
 616         return rc;
 617 }
 618
 619 /**
 620  * ecryptfs_kill_block_super
 621  * @sb: The ecryptfs super block
 622  *
 623  * Used to bring the superblock down and free the private data.
 624  * Private data is free'd in ecryptfs_put_super()
 625  */
 626 static void ecryptfs_kill_block_super(struct super_block *sb)
 627 {
 628         generic_shutdown_super(sb);
 629 }
 630
 631 static struct file_system_type ecryptfs_fs_type = {
 632         .owner = THIS_MODULE,
 633         .name = "ecryptfs",
 634         .get_sb = ecryptfs_get_sb,
 635         .kill_sb = ecryptfs_kill_block_super,
 636         .fs_flags = 0
 637 };
 638
 639 /**
 640  * inode_info_init_once
 641  *
 642  * Initializes the ecryptfs_inode_info_cache when it is created
 643  */
 644 static void
 645 inode_info_init_once(void *vptr)
 646 {
 647         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 648
 649         inode_init_once(&ei->vfs_inode);
 650 }
 651
 652 static struct ecryptfs_cache_info {
 653         struct kmem_cache **cache;
 654         const char *name;
 655         size_t size;
 656         void (*ctor)(void *obj);
 657 } ecryptfs_cache_infos[] = {
 658         {
 659                 .cache = &ecryptfs_auth_tok_list_item_cache,
 660                 .name = "ecryptfs_auth_tok_list_item",
 661                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 662         },
 663         {
 664                 .cache = &ecryptfs_file_info_cache,
 665                 .name = "ecryptfs_file_cache",
 666                 .size = sizeof(struct ecryptfs_file_info),
 667         },
 668         {
 669                 .cache = &ecryptfs_dentry_info_cache,
 670                 .name = "ecryptfs_dentry_info_cache",
 671                 .size = sizeof(struct ecryptfs_dentry_info),
 672         },
 673         {
 674                 .cache = &ecryptfs_inode_info_cache,
 675                 .name = "ecryptfs_inode_cache",
 676                 .size = sizeof(struct ecryptfs_inode_info),
 677                 .ctor = inode_info_init_once,
 678         },
 679         {
 680                 .cache = &ecryptfs_sb_info_cache,
 681                 .name = "ecryptfs_sb_cache",
 682                 .size = sizeof(struct ecryptfs_sb_info),
 683         },
 684         {
 685                 .cache = &ecryptfs_header_cache_1,
 686                 .name = "ecryptfs_headers_1",
 687                 .size = PAGE_CACHE_SIZE,
 688         },
 689         {
 690                 .cache = &ecryptfs_header_cache_2,
 691                 .name = "ecryptfs_headers_2",
 692                 .size = PAGE_CACHE_SIZE,
 693         },
 694         {
 695                 .cache = &ecryptfs_xattr_cache,
 696                 .name = "ecryptfs_xattr_cache",
 697                 .size = PAGE_CACHE_SIZE,
 698         },
 699         {
 700                 .cache = &ecryptfs_key_record_cache,
 701                 .name = "ecryptfs_key_record_cache",
 702                 .size = sizeof(struct ecryptfs_key_record),
 703         },
 704         {
 705                 .cache = &ecryptfs_key_sig_cache,
 706                 .name = "ecryptfs_key_sig_cache",
 707                 .size = sizeof(struct ecryptfs_key_sig),
 708         },
 709         {
 710                 .cache = &ecryptfs_global_auth_tok_cache,
 711                 .name = "ecryptfs_global_auth_tok_cache",
 712                 .size = sizeof(struct ecryptfs_global_auth_tok),
 713         },
 714         {
 715                 .cache = &ecryptfs_key_tfm_cache,
 716                 .name = "ecryptfs_key_tfm_cache",
 717                 .size = sizeof(struct ecryptfs_key_tfm),
 718         },
 719         {
 720                 .cache = &ecryptfs_open_req_cache,
 721                 .name = "ecryptfs_open_req_cache",
 722                 .size = sizeof(struct ecryptfs_open_req),
 723         },
 724 };
 725
 726 static void ecryptfs_free_kmem_caches(void)
 727 {
 728         int i;
 729
 730         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 731                 struct ecryptfs_cache_info *info;
 732
 733                 info = &ecryptfs_cache_infos[i];
 734                 if (*(info->cache))
 735                         kmem_cache_destroy(*(info->cache));
 736         }
 737 }
 738
 739 /**
 740  * ecryptfs_init_kmem_caches
 741  *
 742  * Returns zero on success; non-zero otherwise
 743  */
 744 static int ecryptfs_init_kmem_caches(void)
 745 {
 746         int i;
 747
 748         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 749                 struct ecryptfs_cache_info *info;
 750
 751                 info = &ecryptfs_cache_infos[i];
 752                 *(info->cache) = kmem_cache_create(info->name, info->size,
 753                                 0, SLAB_HWCACHE_ALIGN, info->ctor);
 754                 if (!*(info->cache)) {
 755                         ecryptfs_free_kmem_caches();
 756                         ecryptfs_printk(KERN_WARNING, "%s: "
 757                                         "kmem_cache_create failed\n",
 758                                         info->name);
 759                         return -ENOMEM;
 760                 }
 761         }
 762         return 0;
 763 }
 764
 765 static struct kobject *ecryptfs_kobj;
 766
 767 static ssize_t version_show(struct kobject *kobj,
 768                             struct kobj_attribute *attr, char *buff)
 769 {
 770         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 771 }
 772
 773 static struct kobj_attribute version_attr = __ATTR_RO(version);
 774
 775 static struct attribute *attributes[] = {
 776         &version_attr.attr,
 777         NULL,
 778 };
 779
 780 static struct attribute_group attr_group = {
 781         .attrs = attributes,
 782 };
 783
 784 static int do_sysfs_registration(void)
 785 {
 786         int rc;
 787
 788         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 789         if (!ecryptfs_kobj) {
 790                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
 791                 rc = -ENOMEM;
 792                 goto out;
 793         }
 794         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 795         if (rc) {
 796                 printk(KERN_ERR
 797                        "Unable to create ecryptfs version attributes\n");
 798                 kobject_put(ecryptfs_kobj);
 799         }
 800 out:
 801         return rc;
 802 }
 803
 804 static void do_sysfs_unregistration(void)
 805 {
 806         sysfs_remove_group(ecryptfs_kobj, &attr_group);
 807         kobject_put(ecryptfs_kobj);
 808 }
 809
 810 static int __init ecryptfs_init(void)
 811 {
 812         int rc;
 813
 814         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
 815                 rc = -EINVAL;
 816                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 817                                 "larger than the host's page size, and so "
 818                                 "eCryptfs cannot run on this system. The "
 819                                 "default eCryptfs extent size is [%d] bytes; "
 820                                 "the page size is [%d] bytes.\n",
 821                                 ECRYPTFS_DEFAULT_EXTENT_SIZE, PAGE_CACHE_SIZE);
 822                 goto out;
 823         }
 824         rc = ecryptfs_init_kmem_caches();
 825         if (rc) {
 826                 printk(KERN_ERR
 827                        "Failed to allocate one or more kmem_cache objects\n");
 828                 goto out;
 829         }
 830         rc = register_filesystem(&ecryptfs_fs_type);
 831         if (rc) {
 832                 printk(KERN_ERR "Failed to register filesystem\n");
 833                 goto out_free_kmem_caches;
 834         }
 835         rc = do_sysfs_registration();
 836         if (rc) {
 837                 printk(KERN_ERR "sysfs registration failed\n");
 838                 goto out_unregister_filesystem;
 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 occured 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         if (ecryptfs_verbosity > 0)
 860                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 861                         "will be written to the syslog!\n", ecryptfs_verbosity);
 862
 863         goto out;
 864 out_release_messaging:
 865         ecryptfs_release_messaging();
 866 out_destroy_kthread:
 867         ecryptfs_destroy_kthread();
 868 out_do_sysfs_unregistration:
 869         do_sysfs_unregistration();
 870 out_unregister_filesystem:
 871         unregister_filesystem(&ecryptfs_fs_type);
 872 out_free_kmem_caches:
 873         ecryptfs_free_kmem_caches();
 874 out:
 875         return rc;
 876 }
 877
 878 static void __exit ecryptfs_exit(void)
 879 {
 880         int rc;
 881
 882         rc = ecryptfs_destroy_crypto();
 883         if (rc)
 884                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 885                        "rc = [%d]\n", rc);
 886         ecryptfs_release_messaging();
 887         ecryptfs_destroy_kthread();
 888         do_sysfs_unregistration();
 889         unregister_filesystem(&ecryptfs_fs_type);
 890         ecryptfs_free_kmem_caches();
 891 }
 892
 893 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 894 MODULE_DESCRIPTION("eCryptfs");
 895
 896 MODULE_LICENSE("GPL");
 897
 898 module_init(ecryptfs_init)
 899 module_exit(ecryptfs_exit)