git.oblomov.eu Git - linux-2.6/blob - 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         fsstack_copy_attr_all(inode, lower_inode, NULL);
 194         /* This size will be overwritten for real files w/ headers and
 195          * other metadata */
 196         fsstack_copy_inode_size(inode, lower_inode);
 197         if (flags & ECRYPTFS_INTERPOSE_FLAG_D_ADD)
 198                 d_add(dentry, inode);
 199         else
 200                 d_instantiate(dentry, 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_unlink_sigs, 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_unlink_sigs, "ecryptfs_unlink_sigs"},
 226         {ecryptfs_opt_err, NULL}
 227 };
 228
 229 static int ecryptfs_init_global_auth_toks(
 230         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 231 {
 232         struct ecryptfs_global_auth_tok *global_auth_tok;
 233         int rc = 0;
 234
 235         list_for_each_entry(global_auth_tok,
 236                             &mount_crypt_stat->global_auth_tok_list,
 237                             mount_crypt_stat_list) {
 238                 rc = ecryptfs_keyring_auth_tok_for_sig(
 239                         &global_auth_tok->global_auth_tok_key,
 240                         &global_auth_tok->global_auth_tok,
 241                         global_auth_tok->sig);
 242                 if (rc) {
 243                         printk(KERN_ERR "Could not find valid key in user "
 244                                "session keyring for sig specified in mount "
 245                                "option: [%s]\n", global_auth_tok->sig);
 246                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 247                         goto out;
 248                 } else
 249                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
 250         }
 251 out:
 252         return rc;
 253 }
 254
 255 static void ecryptfs_init_mount_crypt_stat(
 256         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 257 {
 258         memset((void *)mount_crypt_stat, 0,
 259                sizeof(struct ecryptfs_mount_crypt_stat));
 260         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
 261         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
 262         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
 263 }
 264
 265 /**
 266  * ecryptfs_parse_options
 267  * @sb: The ecryptfs super block
 268  * @options: The options pased to the kernel
 269  *
 270  * Parse mount options:
 271  * debug=N         - ecryptfs_verbosity level for debug output
 272  * sig=XXX         - description(signature) of the key to use
 273  *
 274  * Returns the dentry object of the lower-level (lower/interposed)
 275  * directory; We want to mount our stackable file system on top of
 276  * that lower directory.
 277  *
 278  * The signature of the key to use must be the description of a key
 279  * already in the keyring. Mounting will fail if the key can not be
 280  * found.
 281  *
 282  * Returns zero on success; non-zero on error
 283  */
 284 static int ecryptfs_parse_options(struct super_block *sb, char *options)
 285 {
 286         char *p;
 287         int rc = 0;
 288         int sig_set = 0;
 289         int cipher_name_set = 0;
 290         int fn_cipher_name_set = 0;
 291         int cipher_key_bytes;
 292         int cipher_key_bytes_set = 0;
 293         int fn_cipher_key_bytes;
 294         int fn_cipher_key_bytes_set = 0;
 295         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 296                 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
 297         substring_t args[MAX_OPT_ARGS];
 298         int token;
 299         char *sig_src;
 300         char *cipher_name_dst;
 301         char *cipher_name_src;
 302         char *fn_cipher_name_dst;
 303         char *fn_cipher_name_src;
 304         char *fnek_dst;
 305         char *fnek_src;
 306         char *cipher_key_bytes_src;
 307         char *fn_cipher_key_bytes_src;
 308
 309         if (!options) {
 310                 rc = -EINVAL;
 311                 goto out;
 312         }
 313         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
 314         while ((p = strsep(&options, ",")) != NULL) {
 315                 if (!*p)
 316                         continue;
 317                 token = match_token(p, tokens, args);
 318                 switch (token) {
 319                 case ecryptfs_opt_sig:
 320                 case ecryptfs_opt_ecryptfs_sig:
 321                         sig_src = args[0].from;
 322                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
 323                                                           sig_src, 0);
 324                         if (rc) {
 325                                 printk(KERN_ERR "Error attempting to register "
 326                                        "global sig; rc = [%d]\n", rc);
 327                                 goto out;
 328                         }
 329                         sig_set = 1;
 330                         break;
 331                 case ecryptfs_opt_cipher:
 332                 case ecryptfs_opt_ecryptfs_cipher:
 333                         cipher_name_src = args[0].from;
 334                         cipher_name_dst =
 335                                 mount_crypt_stat->
 336                                 global_default_cipher_name;
 337                         strncpy(cipher_name_dst, cipher_name_src,
 338                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 339                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 340                         cipher_name_set = 1;
 341                         break;
 342                 case ecryptfs_opt_ecryptfs_key_bytes:
 343                         cipher_key_bytes_src = args[0].from;
 344                         cipher_key_bytes =
 345                                 (int)simple_strtol(cipher_key_bytes_src,
 346                                                    &cipher_key_bytes_src, 0);
 347                         mount_crypt_stat->global_default_cipher_key_size =
 348                                 cipher_key_bytes;
 349                         cipher_key_bytes_set = 1;
 350                         break;
 351                 case ecryptfs_opt_passthrough:
 352                         mount_crypt_stat->flags |=
 353                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 354                         break;
 355                 case ecryptfs_opt_xattr_metadata:
 356                         mount_crypt_stat->flags |=
 357                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 358                         break;
 359                 case ecryptfs_opt_encrypted_view:
 360                         mount_crypt_stat->flags |=
 361                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 362                         mount_crypt_stat->flags |=
 363                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 364                         break;
 365                 case ecryptfs_opt_fnek_sig:
 366                         fnek_src = args[0].from;
 367                         fnek_dst =
 368                                 mount_crypt_stat->global_default_fnek_sig;
 369                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
 370                         mount_crypt_stat->global_default_fnek_sig[
 371                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
 372                         rc = ecryptfs_add_global_auth_tok(
 373                                 mount_crypt_stat,
 374                                 mount_crypt_stat->global_default_fnek_sig,
 375                                 ECRYPTFS_AUTH_TOK_FNEK);
 376                         if (rc) {
 377                                 printk(KERN_ERR "Error attempting to register "
 378                                        "global fnek sig [%s]; rc = [%d]\n",
 379                                        mount_crypt_stat->global_default_fnek_sig,
 380                                        rc);
 381                                 goto out;
 382                         }
 383                         mount_crypt_stat->flags |=
 384                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 385                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 386                         break;
 387                 case ecryptfs_opt_fn_cipher:
 388                         fn_cipher_name_src = args[0].from;
 389                         fn_cipher_name_dst =
 390                                 mount_crypt_stat->global_default_fn_cipher_name;
 391                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
 392                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 393                         mount_crypt_stat->global_default_fn_cipher_name[
 394                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 395                         fn_cipher_name_set = 1;
 396                         break;
 397                 case ecryptfs_opt_fn_cipher_key_bytes:
 398                         fn_cipher_key_bytes_src = args[0].from;
 399                         fn_cipher_key_bytes =
 400                                 (int)simple_strtol(fn_cipher_key_bytes_src,
 401                                                    &fn_cipher_key_bytes_src, 0);
 402                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
 403                                 fn_cipher_key_bytes;
 404                         fn_cipher_key_bytes_set = 1;
 405                         break;
 406                 case ecryptfs_opt_unlink_sigs:
 407                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
 408                         break;
 409                 case ecryptfs_opt_err:
 410                 default:
 411                         printk(KERN_WARNING
 412                                "%s: eCryptfs: unrecognized option [%s]\n",
 413                                __func__, p);
 414                 }
 415         }
 416         if (!sig_set) {
 417                 rc = -EINVAL;
 418                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
 419                                 "auth tok signature as a mount "
 420                                 "parameter; see the eCryptfs README\n");
 421                 goto out;
 422         }
 423         if (!cipher_name_set) {
 424                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 425
 426                 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 427                 strcpy(mount_crypt_stat->global_default_cipher_name,
 428                        ECRYPTFS_DEFAULT_CIPHER);
 429         }
 430         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 431             && !fn_cipher_name_set)
 432                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
 433                        mount_crypt_stat->global_default_cipher_name);
 434         if (!cipher_key_bytes_set)
 435                 mount_crypt_stat->global_default_cipher_key_size = 0;
 436         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 437             && !fn_cipher_key_bytes_set)
 438                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
 439                         mount_crypt_stat->global_default_cipher_key_size;
 440         mutex_lock(&key_tfm_list_mutex);
 441         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
 442                                  NULL)) {
 443                 rc = ecryptfs_add_new_key_tfm(
 444                         NULL, mount_crypt_stat->global_default_cipher_name,
 445                         mount_crypt_stat->global_default_cipher_key_size);
 446                 if (rc) {
 447                         printk(KERN_ERR "Error attempting to initialize "
 448                                "cipher with name = [%s] and key size = [%td]; "
 449                                "rc = [%d]\n",
 450                                mount_crypt_stat->global_default_cipher_name,
 451                                mount_crypt_stat->global_default_cipher_key_size,
 452                                rc);
 453                         rc = -EINVAL;
 454                         mutex_unlock(&key_tfm_list_mutex);
 455                         goto out;
 456                 }
 457         }
 458         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 459             && !ecryptfs_tfm_exists(
 460                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
 461                 rc = ecryptfs_add_new_key_tfm(
 462                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
 463                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
 464                 if (rc) {
 465                         printk(KERN_ERR "Error attempting to initialize "
 466                                "cipher with name = [%s] and key size = [%td]; "
 467                                "rc = [%d]\n",
 468                                mount_crypt_stat->global_default_fn_cipher_name,
 469                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
 470                                rc);
 471                         rc = -EINVAL;
 472                         mutex_unlock(&key_tfm_list_mutex);
 473                         goto out;
 474                 }
 475         }
 476         mutex_unlock(&key_tfm_list_mutex);
 477         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
 478         if (rc)
 479                 printk(KERN_WARNING "One or more global auth toks could not "
 480                        "properly register; rc = [%d]\n", rc);
 481 out:
 482         return rc;
 483 }
 484
 485 struct kmem_cache *ecryptfs_sb_info_cache;
 486
 487 /**
 488  * ecryptfs_fill_super
 489  * @sb: The ecryptfs super block
 490  * @raw_data: The options passed to mount
 491  * @silent: Not used but required by function prototype
 492  *
 493  * Sets up what we can of the sb, rest is done in ecryptfs_read_super
 494  *
 495  * Returns zero on success; non-zero otherwise
 496  */
 497 static int
 498 ecryptfs_fill_super(struct super_block *sb, void *raw_data, int silent)
 499 {
 500         int rc = 0;
 501
 502         /* Released in ecryptfs_put_super() */
 503         ecryptfs_set_superblock_private(sb,
 504                                         kmem_cache_zalloc(ecryptfs_sb_info_cache,
 505                                                          GFP_KERNEL));
 506         if (!ecryptfs_superblock_to_private(sb)) {
 507                 ecryptfs_printk(KERN_WARNING, "Out of memory\n");
 508                 rc = -ENOMEM;
 509                 goto out;
 510         }
 511         sb->s_op = &ecryptfs_sops;
 512         /* Released through deactivate_super(sb) from get_sb_nodev */
 513         sb->s_root = d_alloc(NULL, &(const struct qstr) {
 514                              .hash = 0,.name = "/",.len = 1});
 515         if (!sb->s_root) {
 516                 ecryptfs_printk(KERN_ERR, "d_alloc failed\n");
 517                 rc = -ENOMEM;
 518                 goto out;
 519         }
 520         sb->s_root->d_op = &ecryptfs_dops;
 521         sb->s_root->d_sb = sb;
 522         sb->s_root->d_parent = sb->s_root;
 523         /* Released in d_release when dput(sb->s_root) is called */
 524         /* through deactivate_super(sb) from get_sb_nodev() */
 525         ecryptfs_set_dentry_private(sb->s_root,
 526                                     kmem_cache_zalloc(ecryptfs_dentry_info_cache,
 527                                                      GFP_KERNEL));
 528         if (!ecryptfs_dentry_to_private(sb->s_root)) {
 529                 ecryptfs_printk(KERN_ERR,
 530                                 "dentry_info_cache alloc failed\n");
 531                 rc = -ENOMEM;
 532                 goto out;
 533         }
 534         rc = 0;
 535 out:
 536         /* Should be able to rely on deactivate_super called from
 537          * get_sb_nodev */
 538         return rc;
 539 }
 540
 541 /**
 542  * ecryptfs_read_super
 543  * @sb: The ecryptfs super block
 544  * @dev_name: The path to mount over
 545  *
 546  * Read the super block of the lower filesystem, and use
 547  * ecryptfs_interpose to create our initial inode and super block
 548  * struct.
 549  */
 550 static int ecryptfs_read_super(struct super_block *sb, const char *dev_name)
 551 {
 552         struct path path;
 553         int rc;
 554
 555         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 556         if (rc) {
 557                 ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n");
 558                 goto out;
 559         }
 560         ecryptfs_set_superblock_lower(sb, path.dentry->d_sb);
 561         sb->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 562         sb->s_blocksize = path.dentry->d_sb->s_blocksize;
 563         ecryptfs_set_dentry_lower(sb->s_root, path.dentry);
 564         ecryptfs_set_dentry_lower_mnt(sb->s_root, path.mnt);
 565         rc = ecryptfs_interpose(path.dentry, sb->s_root, sb, 0);
 566         if (rc)
 567                 goto out_free;
 568         rc = 0;
 569         goto out;
 570 out_free:
 571         path_put(&path);
 572 out:
 573         return rc;
 574 }
 575
 576 /**
 577  * ecryptfs_get_sb
 578  * @fs_type
 579  * @flags
 580  * @dev_name: The path to mount over
 581  * @raw_data: The options passed into the kernel
 582  *
 583  * The whole ecryptfs_get_sb process is broken into 4 functions:
 584  * ecryptfs_parse_options(): handle options passed to ecryptfs, if any
 585  * ecryptfs_fill_super(): used by get_sb_nodev, fills out the super_block
 586  *                        with as much information as it can before needing
 587  *                        the lower filesystem.
 588  * ecryptfs_read_super(): this accesses the lower filesystem and uses
 589  *                        ecryptfs_interpolate to perform most of the linking
 590  * ecryptfs_interpolate(): links the lower filesystem into ecryptfs
 591  */
 592 static int ecryptfs_get_sb(struct file_system_type *fs_type, int flags,
 593                         const char *dev_name, void *raw_data,
 594                         struct vfsmount *mnt)
 595 {
 596         int rc;
 597         struct super_block *sb;
 598
 599         rc = get_sb_nodev(fs_type, flags, raw_data, ecryptfs_fill_super, mnt);
 600         if (rc < 0) {
 601                 printk(KERN_ERR "Getting sb failed; rc = [%d]\n", rc);
 602                 goto out;
 603         }
 604         sb = mnt->mnt_sb;
 605         rc = ecryptfs_parse_options(sb, raw_data);
 606         if (rc) {
 607                 printk(KERN_ERR "Error parsing options; rc = [%d]\n", rc);
 608                 goto out_abort;
 609         }
 610         rc = ecryptfs_read_super(sb, dev_name);
 611         if (rc) {
 612                 printk(KERN_ERR "Reading sb failed; rc = [%d]\n", rc);
 613                 goto out_abort;
 614         }
 615         goto out;
 616 out_abort:
 617         dput(sb->s_root); /* aka mnt->mnt_root, as set by get_sb_nodev() */
 618         deactivate_locked_super(sb);
 619 out:
 620         return rc;
 621 }
 622
 623 /**
 624  * ecryptfs_kill_block_super
 625  * @sb: The ecryptfs super block
 626  *
 627  * Used to bring the superblock down and free the private data.
 628  * Private data is free'd in ecryptfs_put_super()
 629  */
 630 static void ecryptfs_kill_block_super(struct super_block *sb)
 631 {
 632         generic_shutdown_super(sb);
 633 }
 634
 635 static struct file_system_type ecryptfs_fs_type = {
 636         .owner = THIS_MODULE,
 637         .name = "ecryptfs",
 638         .get_sb = ecryptfs_get_sb,
 639         .kill_sb = ecryptfs_kill_block_super,
 640         .fs_flags = 0
 641 };
 642
 643 /**
 644  * inode_info_init_once
 645  *
 646  * Initializes the ecryptfs_inode_info_cache when it is created
 647  */
 648 static void
 649 inode_info_init_once(void *vptr)
 650 {
 651         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 652
 653         inode_init_once(&ei->vfs_inode);
 654 }
 655
 656 static struct ecryptfs_cache_info {
 657         struct kmem_cache **cache;
 658         const char *name;
 659         size_t size;
 660         void (*ctor)(void *obj);
 661 } ecryptfs_cache_infos[] = {
 662         {
 663                 .cache = &ecryptfs_auth_tok_list_item_cache,
 664                 .name = "ecryptfs_auth_tok_list_item",
 665                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 666         },
 667         {
 668                 .cache = &ecryptfs_file_info_cache,
 669                 .name = "ecryptfs_file_cache",
 670                 .size = sizeof(struct ecryptfs_file_info),
 671         },
 672         {
 673                 .cache = &ecryptfs_dentry_info_cache,
 674                 .name = "ecryptfs_dentry_info_cache",
 675                 .size = sizeof(struct ecryptfs_dentry_info),
 676         },
 677         {
 678                 .cache = &ecryptfs_inode_info_cache,
 679                 .name = "ecryptfs_inode_cache",
 680                 .size = sizeof(struct ecryptfs_inode_info),
 681                 .ctor = inode_info_init_once,
 682         },
 683         {
 684                 .cache = &ecryptfs_sb_info_cache,
 685                 .name = "ecryptfs_sb_cache",
 686                 .size = sizeof(struct ecryptfs_sb_info),
 687         },
 688         {
 689                 .cache = &ecryptfs_header_cache_1,
 690                 .name = "ecryptfs_headers_1",
 691                 .size = PAGE_CACHE_SIZE,
 692         },
 693         {
 694                 .cache = &ecryptfs_header_cache_2,
 695                 .name = "ecryptfs_headers_2",
 696                 .size = PAGE_CACHE_SIZE,
 697         },
 698         {
 699                 .cache = &ecryptfs_xattr_cache,
 700                 .name = "ecryptfs_xattr_cache",
 701                 .size = PAGE_CACHE_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                 .cache = &ecryptfs_open_req_cache,
 725                 .name = "ecryptfs_open_req_cache",
 726                 .size = sizeof(struct ecryptfs_open_req),
 727         },
 728 };
 729
 730 static void ecryptfs_free_kmem_caches(void)
 731 {
 732         int i;
 733
 734         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 735                 struct ecryptfs_cache_info *info;
 736
 737                 info = &ecryptfs_cache_infos[i];
 738                 if (*(info->cache))
 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,
 757                                 0, SLAB_HWCACHE_ALIGN, 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 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_CACHE_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 [%d] bytes; "
 824                                 "the page size is [%d] bytes.\n",
 825                                 ECRYPTFS_DEFAULT_EXTENT_SIZE, PAGE_CACHE_SIZE);
 826                 goto out;
 827         }
 828         rc = ecryptfs_init_kmem_caches();
 829         if (rc) {
 830                 printk(KERN_ERR
 831                        "Failed to allocate one or more kmem_cache objects\n");
 832                 goto out;
 833         }
 834         rc = register_filesystem(&ecryptfs_fs_type);
 835         if (rc) {
 836                 printk(KERN_ERR "Failed to register filesystem\n");
 837                 goto out_free_kmem_caches;
 838         }
 839         rc = do_sysfs_registration();
 840         if (rc) {
 841                 printk(KERN_ERR "sysfs registration failed\n");
 842                 goto out_unregister_filesystem;
 843         }
 844         rc = ecryptfs_init_kthread();
 845         if (rc) {
 846                 printk(KERN_ERR "%s: kthread initialization failed; "
 847                        "rc = [%d]\n", __func__, rc);
 848                 goto out_do_sysfs_unregistration;
 849         }
 850         rc = ecryptfs_init_messaging();
 851         if (rc) {
 852                 printk(KERN_ERR "Failure occured while attempting to "
 853                                 "initialize the communications channel to "
 854                                 "ecryptfsd\n");
 855                 goto out_destroy_kthread;
 856         }
 857         rc = ecryptfs_init_crypto();
 858         if (rc) {
 859                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
 860                        "rc = [%d]\n", rc);
 861                 goto out_release_messaging;
 862         }
 863         if (ecryptfs_verbosity > 0)
 864                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 865                         "will be written to the syslog!\n", ecryptfs_verbosity);
 866
 867         goto out;
 868 out_release_messaging:
 869         ecryptfs_release_messaging();
 870 out_destroy_kthread:
 871         ecryptfs_destroy_kthread();
 872 out_do_sysfs_unregistration:
 873         do_sysfs_unregistration();
 874 out_unregister_filesystem:
 875         unregister_filesystem(&ecryptfs_fs_type);
 876 out_free_kmem_caches:
 877         ecryptfs_free_kmem_caches();
 878 out:
 879         return rc;
 880 }
 881
 882 static void __exit ecryptfs_exit(void)
 883 {
 884         int rc;
 885
 886         rc = ecryptfs_destroy_crypto();
 887         if (rc)
 888                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 889                        "rc = [%d]\n", rc);
 890         ecryptfs_release_messaging();
 891         ecryptfs_destroy_kthread();
 892         do_sysfs_unregistration();
 893         unregister_filesystem(&ecryptfs_fs_type);
 894         ecryptfs_free_kmem_caches();
 895 }
 896
 897 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 898 MODULE_DESCRIPTION("eCryptfs");
 899
 900 MODULE_LICENSE("GPL");
 901
 902 module_init(ecryptfs_init)
 903 module_exit(ecryptfs_exit)