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) 2004-2006 International Business Machines Corp.
   7  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
   8  *              Michael C. Thompson <mcthomps@us.ibm.com>
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation; either version 2 of the
  13  * License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  23  * 02111-1307, USA.
  24  */
  25
  26 #include <linux/dcache.h>
  27 #include <linux/file.h>
  28 #include <linux/module.h>
  29 #include <linux/namei.h>
  30 #include <linux/skbuff.h>
  31 #include <linux/crypto.h>
  32 #include <linux/netlink.h>
  33 #include <linux/mount.h>
  34 #include <linux/dcache.h>
  35 #include <linux/pagemap.h>
  36 #include <linux/key.h>
  37 #include <linux/parser.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 void __ecryptfs_printk(const char *fmt, ...)
  51 {
  52         va_list args;
  53         va_start(args, fmt);
  54         if (fmt[1] == '7') { /* KERN_DEBUG */
  55                 if (ecryptfs_verbosity >= 1)
  56                         vprintk(fmt, args);
  57         } else
  58                 vprintk(fmt, args);
  59         va_end(args);
  60 }
  61
  62 /**
  63  * ecryptfs_interpose
  64  * @lower_dentry: Existing dentry in the lower filesystem
  65  * @dentry: ecryptfs' dentry
  66  * @sb: ecryptfs's super_block
  67  * @flag: If set to true, then d_add is called, else d_instantiate is called
  68  *
  69  * Interposes upper and lower dentries.
  70  *
  71  * Returns zero on success; non-zero otherwise
  72  */
  73 int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
  74                        struct super_block *sb, int flag)
  75 {
  76         struct inode *lower_inode;
  77         struct inode *inode;
  78         int rc = 0;
  79
  80         lower_inode = lower_dentry->d_inode;
  81         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) {
  82                 rc = -EXDEV;
  83                 goto out;
  84         }
  85         if (!igrab(lower_inode)) {
  86                 rc = -ESTALE;
  87                 goto out;
  88         }
  89         inode = iget5_locked(sb, (unsigned long)lower_inode,
  90                              ecryptfs_inode_test, ecryptfs_inode_set,
  91                              lower_inode);
  92         if (!inode) {
  93                 rc = -EACCES;
  94                 iput(lower_inode);
  95                 goto out;
  96         }
  97         if (inode->i_state & I_NEW)
  98                 unlock_new_inode(inode);
  99         else
 100                 iput(lower_inode);
 101         if (S_ISLNK(lower_inode->i_mode))
 102                 inode->i_op = &ecryptfs_symlink_iops;
 103         else if (S_ISDIR(lower_inode->i_mode))
 104                 inode->i_op = &ecryptfs_dir_iops;
 105         if (S_ISDIR(lower_inode->i_mode))
 106                 inode->i_fop = &ecryptfs_dir_fops;
 107         if (special_file(lower_inode->i_mode))
 108                 init_special_inode(inode, lower_inode->i_mode,
 109                                    lower_inode->i_rdev);
 110         dentry->d_op = &ecryptfs_dops;
 111         if (flag)
 112                 d_add(dentry, inode);
 113         else
 114                 d_instantiate(dentry, inode);
 115         ecryptfs_copy_attr_all(inode, lower_inode);
 116         /* This size will be overwritten for real files w/ headers and
 117          * other metadata */
 118         ecryptfs_copy_inode_size(inode, lower_inode);
 119 out:
 120         return rc;
 121 }
 122
 123 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig, ecryptfs_opt_debug,
 124        ecryptfs_opt_ecryptfs_debug, ecryptfs_opt_cipher,
 125        ecryptfs_opt_ecryptfs_cipher, ecryptfs_opt_ecryptfs_key_bytes,
 126        ecryptfs_opt_passthrough, ecryptfs_opt_err };
 127
 128 static match_table_t tokens = {
 129         {ecryptfs_opt_sig, "sig=%s"},
 130         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 131         {ecryptfs_opt_debug, "debug=%u"},
 132         {ecryptfs_opt_ecryptfs_debug, "ecryptfs_debug=%u"},
 133         {ecryptfs_opt_cipher, "cipher=%s"},
 134         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
 135         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
 136         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
 137         {ecryptfs_opt_err, NULL}
 138 };
 139
 140 /**
 141  * ecryptfs_verify_version
 142  * @version: The version number to confirm
 143  *
 144  * Returns zero on good version; non-zero otherwise
 145  */
 146 static int ecryptfs_verify_version(u16 version)
 147 {
 148         int rc = 0;
 149         unsigned char major;
 150         unsigned char minor;
 151
 152         major = ((version >> 8) & 0xFF);
 153         minor = (version & 0xFF);
 154         if (major != ECRYPTFS_VERSION_MAJOR) {
 155                 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
 156                                 "Expected [%d]; got [%d]\n",
 157                                 ECRYPTFS_VERSION_MAJOR, major);
 158                 rc = -EINVAL;
 159                 goto out;
 160         }
 161         if (minor != ECRYPTFS_VERSION_MINOR) {
 162                 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
 163                                 "Expected [%d]; got [%d]\n",
 164                                 ECRYPTFS_VERSION_MINOR, minor);
 165                 rc = -EINVAL;
 166                 goto out;
 167         }
 168 out:
 169         return rc;
 170 }
 171
 172 /**
 173  * ecryptfs_parse_options
 174  * @sb: The ecryptfs super block
 175  * @options: The options pased to the kernel
 176  *
 177  * Parse mount options:
 178  * debug=N         - ecryptfs_verbosity level for debug output
 179  * sig=XXX         - description(signature) of the key to use
 180  *
 181  * Returns the dentry object of the lower-level (lower/interposed)
 182  * directory; We want to mount our stackable file system on top of
 183  * that lower directory.
 184  *
 185  * The signature of the key to use must be the description of a key
 186  * already in the keyring. Mounting will fail if the key can not be
 187  * found.
 188  *
 189  * Returns zero on success; non-zero on error
 190  */
 191 static int ecryptfs_parse_options(struct super_block *sb, char *options)
 192 {
 193         char *p;
 194         int rc = 0;
 195         int sig_set = 0;
 196         int cipher_name_set = 0;
 197         int cipher_key_bytes;
 198         int cipher_key_bytes_set = 0;
 199         struct key *auth_tok_key = NULL;
 200         struct ecryptfs_auth_tok *auth_tok = NULL;
 201         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 202                 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
 203         substring_t args[MAX_OPT_ARGS];
 204         int token;
 205         char *sig_src;
 206         char *sig_dst;
 207         char *debug_src;
 208         char *cipher_name_dst;
 209         char *cipher_name_src;
 210         char *cipher_key_bytes_src;
 211         int cipher_name_len;
 212
 213         if (!options) {
 214                 rc = -EINVAL;
 215                 goto out;
 216         }
 217         while ((p = strsep(&options, ",")) != NULL) {
 218                 if (!*p)
 219                         continue;
 220                 token = match_token(p, tokens, args);
 221                 switch (token) {
 222                 case ecryptfs_opt_sig:
 223                 case ecryptfs_opt_ecryptfs_sig:
 224                         sig_src = args[0].from;
 225                         sig_dst =
 226                                 mount_crypt_stat->global_auth_tok_sig;
 227                         memcpy(sig_dst, sig_src, ECRYPTFS_SIG_SIZE_HEX);
 228                         sig_dst[ECRYPTFS_SIG_SIZE_HEX] = '\0';
 229                         ecryptfs_printk(KERN_DEBUG,
 230                                         "The mount_crypt_stat "
 231                                         "global_auth_tok_sig set to: "
 232                                         "[%s]\n", sig_dst);
 233                         sig_set = 1;
 234                         break;
 235                 case ecryptfs_opt_debug:
 236                 case ecryptfs_opt_ecryptfs_debug:
 237                         debug_src = args[0].from;
 238                         ecryptfs_verbosity =
 239                                 (int)simple_strtol(debug_src, &debug_src,
 240                                                    0);
 241                         ecryptfs_printk(KERN_DEBUG,
 242                                         "Verbosity set to [%d]" "\n",
 243                                         ecryptfs_verbosity);
 244                         break;
 245                 case ecryptfs_opt_cipher:
 246                 case ecryptfs_opt_ecryptfs_cipher:
 247                         cipher_name_src = args[0].from;
 248                         cipher_name_dst =
 249                                 mount_crypt_stat->
 250                                 global_default_cipher_name;
 251                         strncpy(cipher_name_dst, cipher_name_src,
 252                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 253                         ecryptfs_printk(KERN_DEBUG,
 254                                         "The mount_crypt_stat "
 255                                         "global_default_cipher_name set to: "
 256                                         "[%s]\n", cipher_name_dst);
 257                         cipher_name_set = 1;
 258                         break;
 259                 case ecryptfs_opt_ecryptfs_key_bytes:
 260                         cipher_key_bytes_src = args[0].from;
 261                         cipher_key_bytes =
 262                                 (int)simple_strtol(cipher_key_bytes_src,
 263                                                    &cipher_key_bytes_src, 0);
 264                         mount_crypt_stat->global_default_cipher_key_size =
 265                                 cipher_key_bytes;
 266                         ecryptfs_printk(KERN_DEBUG,
 267                                         "The mount_crypt_stat "
 268                                         "global_default_cipher_key_size "
 269                                         "set to: [%d]\n", mount_crypt_stat->
 270                                         global_default_cipher_key_size);
 271                         cipher_key_bytes_set = 1;
 272                         break;
 273                 case ecryptfs_opt_passthrough:
 274                         mount_crypt_stat->flags |=
 275                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 276                         break;
 277                 case ecryptfs_opt_err:
 278                 default:
 279                         ecryptfs_printk(KERN_WARNING,
 280                                         "eCryptfs: unrecognized option '%s'\n",
 281                                         p);
 282                 }
 283         }
 284         /* Do not support lack of mount-wide signature in 0.1
 285          * release */
 286         if (!sig_set) {
 287                 rc = -EINVAL;
 288                 ecryptfs_printk(KERN_ERR, "You must supply a valid "
 289                                 "passphrase auth tok signature as a mount "
 290                                 "parameter; see the eCryptfs README\n");
 291                 goto out;
 292         }
 293         if (!cipher_name_set) {
 294                 cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 295                 if (unlikely(cipher_name_len
 296                              >= ECRYPTFS_MAX_CIPHER_NAME_SIZE)) {
 297                         rc = -EINVAL;
 298                         BUG();
 299                         goto out;
 300                 }
 301                 memcpy(mount_crypt_stat->global_default_cipher_name,
 302                        ECRYPTFS_DEFAULT_CIPHER, cipher_name_len);
 303                 mount_crypt_stat->global_default_cipher_name[cipher_name_len]
 304                     = '\0';
 305         }
 306         if (!cipher_key_bytes_set) {
 307                 mount_crypt_stat->global_default_cipher_key_size = 0;
 308         }
 309         rc = ecryptfs_process_cipher(
 310                 &mount_crypt_stat->global_key_tfm,
 311                 mount_crypt_stat->global_default_cipher_name,
 312                 &mount_crypt_stat->global_default_cipher_key_size);
 313         if (rc) {
 314                 printk(KERN_ERR "Error attempting to initialize cipher [%s] "
 315                        "with key size [%Zd] bytes; rc = [%d]\n",
 316                        mount_crypt_stat->global_default_cipher_name,
 317                        mount_crypt_stat->global_default_cipher_key_size, rc);
 318                 mount_crypt_stat->global_key_tfm = NULL;
 319                 mount_crypt_stat->global_auth_tok_key = NULL;
 320                 rc = -EINVAL;
 321                 goto out;
 322         }
 323         mutex_init(&mount_crypt_stat->global_key_tfm_mutex);
 324         ecryptfs_printk(KERN_DEBUG, "Requesting the key with description: "
 325                         "[%s]\n", mount_crypt_stat->global_auth_tok_sig);
 326         /* The reference to this key is held until umount is done The
 327          * call to key_put is done in ecryptfs_put_super() */
 328         auth_tok_key = request_key(&key_type_user,
 329                                    mount_crypt_stat->global_auth_tok_sig,
 330                                    NULL);
 331         if (!auth_tok_key || IS_ERR(auth_tok_key)) {
 332                 ecryptfs_printk(KERN_ERR, "Could not find key with "
 333                                 "description: [%s]\n",
 334                                 mount_crypt_stat->global_auth_tok_sig);
 335                 process_request_key_err(PTR_ERR(auth_tok_key));
 336                 rc = -EINVAL;
 337                 goto out;
 338         }
 339         auth_tok = ecryptfs_get_key_payload_data(auth_tok_key);
 340         if (ecryptfs_verify_version(auth_tok->version)) {
 341                 ecryptfs_printk(KERN_ERR, "Data structure version mismatch. "
 342                                 "Userspace tools must match eCryptfs kernel "
 343                                 "module with major version [%d] and minor "
 344                                 "version [%d]\n", ECRYPTFS_VERSION_MAJOR,
 345                                 ECRYPTFS_VERSION_MINOR);
 346                 rc = -EINVAL;
 347                 goto out;
 348         }
 349         if (auth_tok->token_type != ECRYPTFS_PASSWORD) {
 350                 ecryptfs_printk(KERN_ERR, "Invalid auth_tok structure "
 351                                 "returned from key\n");
 352                 rc = -EINVAL;
 353                 goto out;
 354         }
 355         mount_crypt_stat->global_auth_tok_key = auth_tok_key;
 356         mount_crypt_stat->global_auth_tok = auth_tok;
 357 out:
 358         return rc;
 359 }
 360
 361 struct kmem_cache *ecryptfs_sb_info_cache;
 362
 363 /**
 364  * ecryptfs_fill_super
 365  * @sb: The ecryptfs super block
 366  * @raw_data: The options passed to mount
 367  * @silent: Not used but required by function prototype
 368  *
 369  * Sets up what we can of the sb, rest is done in ecryptfs_read_super
 370  *
 371  * Returns zero on success; non-zero otherwise
 372  */
 373 static int
 374 ecryptfs_fill_super(struct super_block *sb, void *raw_data, int silent)
 375 {
 376         int rc = 0;
 377
 378         /* Released in ecryptfs_put_super() */
 379         ecryptfs_set_superblock_private(sb,
 380                                         kmem_cache_alloc(ecryptfs_sb_info_cache,
 381                                                          SLAB_KERNEL));
 382         if (!ecryptfs_superblock_to_private(sb)) {
 383                 ecryptfs_printk(KERN_WARNING, "Out of memory\n");
 384                 rc = -ENOMEM;
 385                 goto out;
 386         }
 387         memset(ecryptfs_superblock_to_private(sb), 0,
 388                sizeof(struct ecryptfs_sb_info));
 389         sb->s_op = &ecryptfs_sops;
 390         /* Released through deactivate_super(sb) from get_sb_nodev */
 391         sb->s_root = d_alloc(NULL, &(const struct qstr) {
 392                              .hash = 0,.name = "/",.len = 1});
 393         if (!sb->s_root) {
 394                 ecryptfs_printk(KERN_ERR, "d_alloc failed\n");
 395                 rc = -ENOMEM;
 396                 goto out;
 397         }
 398         sb->s_root->d_op = &ecryptfs_dops;
 399         sb->s_root->d_sb = sb;
 400         sb->s_root->d_parent = sb->s_root;
 401         /* Released in d_release when dput(sb->s_root) is called */
 402         /* through deactivate_super(sb) from get_sb_nodev() */
 403         ecryptfs_set_dentry_private(sb->s_root,
 404                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
 405                                                      SLAB_KERNEL));
 406         if (!ecryptfs_dentry_to_private(sb->s_root)) {
 407                 ecryptfs_printk(KERN_ERR,
 408                                 "dentry_info_cache alloc failed\n");
 409                 rc = -ENOMEM;
 410                 goto out;
 411         }
 412         memset(ecryptfs_dentry_to_private(sb->s_root), 0,
 413                sizeof(struct ecryptfs_dentry_info));
 414         rc = 0;
 415 out:
 416         /* Should be able to rely on deactivate_super called from
 417          * get_sb_nodev */
 418         return rc;
 419 }
 420
 421 /**
 422  * ecryptfs_read_super
 423  * @sb: The ecryptfs super block
 424  * @dev_name: The path to mount over
 425  *
 426  * Read the super block of the lower filesystem, and use
 427  * ecryptfs_interpose to create our initial inode and super block
 428  * struct.
 429  */
 430 static int ecryptfs_read_super(struct super_block *sb, const char *dev_name)
 431 {
 432         int rc;
 433         struct nameidata nd;
 434         struct dentry *lower_root;
 435         struct vfsmount *lower_mnt;
 436
 437         memset(&nd, 0, sizeof(struct nameidata));
 438         rc = path_lookup(dev_name, LOOKUP_FOLLOW, &nd);
 439         if (rc) {
 440                 ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n");
 441                 goto out_free;
 442         }
 443         lower_root = nd.dentry;
 444         if (!lower_root->d_inode) {
 445                 ecryptfs_printk(KERN_WARNING,
 446                                 "No directory to interpose on\n");
 447                 rc = -ENOENT;
 448                 goto out_free;
 449         }
 450         lower_mnt = nd.mnt;
 451         ecryptfs_set_superblock_lower(sb, lower_root->d_sb);
 452         sb->s_maxbytes = lower_root->d_sb->s_maxbytes;
 453         ecryptfs_set_dentry_lower(sb->s_root, lower_root);
 454         ecryptfs_set_dentry_lower_mnt(sb->s_root, lower_mnt);
 455         if ((rc = ecryptfs_interpose(lower_root, sb->s_root, sb, 0)))
 456                 goto out_free;
 457         rc = 0;
 458         goto out;
 459 out_free:
 460         path_release(&nd);
 461 out:
 462         return rc;
 463 }
 464
 465 /**
 466  * ecryptfs_get_sb
 467  * @fs_type
 468  * @flags
 469  * @dev_name: The path to mount over
 470  * @raw_data: The options passed into the kernel
 471  *
 472  * The whole ecryptfs_get_sb process is broken into 4 functions:
 473  * ecryptfs_parse_options(): handle options passed to ecryptfs, if any
 474  * ecryptfs_fill_super(): used by get_sb_nodev, fills out the super_block
 475  *                        with as much information as it can before needing
 476  *                        the lower filesystem.
 477  * ecryptfs_read_super(): this accesses the lower filesystem and uses
 478  *                        ecryptfs_interpolate to perform most of the linking
 479  * ecryptfs_interpolate(): links the lower filesystem into ecryptfs
 480  */
 481 static int ecryptfs_get_sb(struct file_system_type *fs_type, int flags,
 482                         const char *dev_name, void *raw_data,
 483                         struct vfsmount *mnt)
 484 {
 485         int rc;
 486         struct super_block *sb;
 487
 488         rc = get_sb_nodev(fs_type, flags, raw_data, ecryptfs_fill_super, mnt);
 489         if (rc < 0) {
 490                 printk(KERN_ERR "Getting sb failed; rc = [%d]\n", rc);
 491                 goto out;
 492         }
 493         sb = mnt->mnt_sb;
 494         rc = ecryptfs_parse_options(sb, raw_data);
 495         if (rc) {
 496                 printk(KERN_ERR "Error parsing options; rc = [%d]\n", rc);
 497                 goto out_abort;
 498         }
 499         rc = ecryptfs_read_super(sb, dev_name);
 500         if (rc) {
 501                 printk(KERN_ERR "Reading sb failed; rc = [%d]\n", rc);
 502                 goto out_abort;
 503         }
 504         goto out;
 505 out_abort:
 506         dput(sb->s_root);
 507         up_write(&sb->s_umount);
 508         deactivate_super(sb);
 509 out:
 510         return rc;
 511 }
 512
 513 /**
 514  * ecryptfs_kill_block_super
 515  * @sb: The ecryptfs super block
 516  *
 517  * Used to bring the superblock down and free the private data.
 518  * Private data is free'd in ecryptfs_put_super()
 519  */
 520 static void ecryptfs_kill_block_super(struct super_block *sb)
 521 {
 522         generic_shutdown_super(sb);
 523 }
 524
 525 static struct file_system_type ecryptfs_fs_type = {
 526         .owner = THIS_MODULE,
 527         .name = "ecryptfs",
 528         .get_sb = ecryptfs_get_sb,
 529         .kill_sb = ecryptfs_kill_block_super,
 530         .fs_flags = 0
 531 };
 532
 533 /**
 534  * inode_info_init_once
 535  *
 536  * Initializes the ecryptfs_inode_info_cache when it is created
 537  */
 538 static void
 539 inode_info_init_once(void *vptr, struct kmem_cache *cachep, unsigned long flags)
 540 {
 541         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 542
 543         if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) ==
 544             SLAB_CTOR_CONSTRUCTOR)
 545                 inode_init_once(&ei->vfs_inode);
 546 }
 547
 548 static struct ecryptfs_cache_info {
 549         kmem_cache_t **cache;
 550         const char *name;
 551         size_t size;
 552         void (*ctor)(void*, struct kmem_cache *, unsigned long);
 553 } ecryptfs_cache_infos[] = {
 554         {
 555                 .cache = &ecryptfs_auth_tok_list_item_cache,
 556                 .name = "ecryptfs_auth_tok_list_item",
 557                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 558         },
 559         {
 560                 .cache = &ecryptfs_file_info_cache,
 561                 .name = "ecryptfs_file_cache",
 562                 .size = sizeof(struct ecryptfs_file_info),
 563         },
 564         {
 565                 .cache = &ecryptfs_dentry_info_cache,
 566                 .name = "ecryptfs_dentry_info_cache",
 567                 .size = sizeof(struct ecryptfs_dentry_info),
 568         },
 569         {
 570                 .cache = &ecryptfs_inode_info_cache,
 571                 .name = "ecryptfs_inode_cache",
 572                 .size = sizeof(struct ecryptfs_inode_info),
 573                 .ctor = inode_info_init_once,
 574         },
 575         {
 576                 .cache = &ecryptfs_sb_info_cache,
 577                 .name = "ecryptfs_sb_cache",
 578                 .size = sizeof(struct ecryptfs_sb_info),
 579         },
 580         {
 581                 .cache = &ecryptfs_header_cache_0,
 582                 .name = "ecryptfs_headers_0",
 583                 .size = PAGE_CACHE_SIZE,
 584         },
 585         {
 586                 .cache = &ecryptfs_header_cache_1,
 587                 .name = "ecryptfs_headers_1",
 588                 .size = PAGE_CACHE_SIZE,
 589         },
 590         {
 591                 .cache = &ecryptfs_header_cache_2,
 592                 .name = "ecryptfs_headers_2",
 593                 .size = PAGE_CACHE_SIZE,
 594         },
 595         {
 596                 .cache = &ecryptfs_lower_page_cache,
 597                 .name = "ecryptfs_lower_page_cache",
 598                 .size = PAGE_CACHE_SIZE,
 599         },
 600 };
 601
 602 static void ecryptfs_free_kmem_caches(void)
 603 {
 604         int i;
 605
 606         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 607                 struct ecryptfs_cache_info *info;
 608
 609                 info = &ecryptfs_cache_infos[i];
 610                 if (*(info->cache))
 611                         kmem_cache_destroy(*(info->cache));
 612         }
 613 }
 614
 615 /**
 616  * ecryptfs_init_kmem_caches
 617  *
 618  * Returns zero on success; non-zero otherwise
 619  */
 620 static int ecryptfs_init_kmem_caches(void)
 621 {
 622         int i;
 623
 624         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 625                 struct ecryptfs_cache_info *info;
 626
 627                 info = &ecryptfs_cache_infos[i];
 628                 *(info->cache) = kmem_cache_create(info->name, info->size,
 629                                 0, SLAB_HWCACHE_ALIGN, info->ctor, NULL);
 630                 if (!*(info->cache)) {
 631                         ecryptfs_free_kmem_caches();
 632                         ecryptfs_printk(KERN_WARNING, "%s: "
 633                                         "kmem_cache_create failed\n",
 634                                         info->name);
 635                         return -ENOMEM;
 636                 }
 637         }
 638         return 0;
 639 }
 640
 641 struct ecryptfs_obj {
 642         char *name;
 643         struct list_head slot_list;
 644         struct kobject kobj;
 645 };
 646
 647 struct ecryptfs_attribute {
 648         struct attribute attr;
 649         ssize_t(*show) (struct ecryptfs_obj *, char *);
 650         ssize_t(*store) (struct ecryptfs_obj *, const char *, size_t);
 651 };
 652
 653 static ssize_t
 654 ecryptfs_attr_store(struct kobject *kobj,
 655                     struct attribute *attr, const char *buf, size_t len)
 656 {
 657         struct ecryptfs_obj *obj = container_of(kobj, struct ecryptfs_obj,
 658                                                 kobj);
 659         struct ecryptfs_attribute *attribute =
 660                 container_of(attr, struct ecryptfs_attribute, attr);
 661
 662         return (attribute->store ? attribute->store(obj, buf, len) : 0);
 663 }
 664
 665 static ssize_t
 666 ecryptfs_attr_show(struct kobject *kobj, struct attribute *attr, char *buf)
 667 {
 668         struct ecryptfs_obj *obj = container_of(kobj, struct ecryptfs_obj,
 669                                                 kobj);
 670         struct ecryptfs_attribute *attribute =
 671                 container_of(attr, struct ecryptfs_attribute, attr);
 672
 673         return (attribute->show ? attribute->show(obj, buf) : 0);
 674 }
 675
 676 static struct sysfs_ops ecryptfs_sysfs_ops = {
 677         .show = ecryptfs_attr_show,
 678         .store = ecryptfs_attr_store
 679 };
 680
 681 static struct kobj_type ecryptfs_ktype = {
 682         .sysfs_ops = &ecryptfs_sysfs_ops
 683 };
 684
 685 static decl_subsys(ecryptfs, &ecryptfs_ktype, NULL);
 686
 687 static ssize_t version_show(struct ecryptfs_obj *obj, char *buff)
 688 {
 689         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 690 }
 691
 692 static struct ecryptfs_attribute sysfs_attr_version = __ATTR_RO(version);
 693
 694 struct ecryptfs_version_str_map_elem {
 695         u32 flag;
 696         char *str;
 697 } ecryptfs_version_str_map[] = {
 698         {ECRYPTFS_VERSIONING_PASSPHRASE, "passphrase"},
 699         {ECRYPTFS_VERSIONING_PUBKEY, "pubkey"},
 700         {ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH, "plaintext passthrough"},
 701         {ECRYPTFS_VERSIONING_POLICY, "policy"}
 702 };
 703
 704 static ssize_t version_str_show(struct ecryptfs_obj *obj, char *buff)
 705 {
 706         int i;
 707         int remaining = PAGE_SIZE;
 708         int total_written = 0;
 709
 710         buff[0] = '\0';
 711         for (i = 0; i < ARRAY_SIZE(ecryptfs_version_str_map); i++) {
 712                 int entry_size;
 713
 714                 if (!(ECRYPTFS_VERSIONING_MASK
 715                       & ecryptfs_version_str_map[i].flag))
 716                         continue;
 717                 entry_size = strlen(ecryptfs_version_str_map[i].str);
 718                 if ((entry_size + 2) > remaining)
 719                         goto out;
 720                 memcpy(buff, ecryptfs_version_str_map[i].str, entry_size);
 721                 buff[entry_size++] = '\n';
 722                 buff[entry_size] = '\0';
 723                 buff += entry_size;
 724                 total_written += entry_size;
 725                 remaining -= entry_size;
 726         }
 727 out:
 728         return total_written;
 729 }
 730
 731 static struct ecryptfs_attribute sysfs_attr_version_str = __ATTR_RO(version_str);
 732
 733 static int do_sysfs_registration(void)
 734 {
 735         int rc;
 736
 737         if ((rc = subsystem_register(&ecryptfs_subsys))) {
 738                 printk(KERN_ERR
 739                        "Unable to register ecryptfs sysfs subsystem\n");
 740                 goto out;
 741         }
 742         rc = sysfs_create_file(&ecryptfs_subsys.kset.kobj,
 743                                &sysfs_attr_version.attr);
 744         if (rc) {
 745                 printk(KERN_ERR
 746                        "Unable to create ecryptfs version attribute\n");
 747                 subsystem_unregister(&ecryptfs_subsys);
 748                 goto out;
 749         }
 750         rc = sysfs_create_file(&ecryptfs_subsys.kset.kobj,
 751                                &sysfs_attr_version_str.attr);
 752         if (rc) {
 753                 printk(KERN_ERR
 754                        "Unable to create ecryptfs version_str attribute\n");
 755                 sysfs_remove_file(&ecryptfs_subsys.kset.kobj,
 756                                   &sysfs_attr_version.attr);
 757                 subsystem_unregister(&ecryptfs_subsys);
 758                 goto out;
 759         }
 760 out:
 761         return rc;
 762 }
 763
 764 static int __init ecryptfs_init(void)
 765 {
 766         int rc;
 767
 768         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
 769                 rc = -EINVAL;
 770                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 771                                 "larger than the host's page size, and so "
 772                                 "eCryptfs cannot run on this system. The "
 773                                 "default eCryptfs extent size is [%d] bytes; "
 774                                 "the page size is [%d] bytes.\n",
 775                                 ECRYPTFS_DEFAULT_EXTENT_SIZE, PAGE_CACHE_SIZE);
 776                 goto out;
 777         }
 778         rc = ecryptfs_init_kmem_caches();
 779         if (rc) {
 780                 printk(KERN_ERR
 781                        "Failed to allocate one or more kmem_cache objects\n");
 782                 goto out;
 783         }
 784         rc = register_filesystem(&ecryptfs_fs_type);
 785         if (rc) {
 786                 printk(KERN_ERR "Failed to register filesystem\n");
 787                 ecryptfs_free_kmem_caches();
 788                 goto out;
 789         }
 790         kset_set_kset_s(&ecryptfs_subsys, fs_subsys);
 791         sysfs_attr_version.attr.owner = THIS_MODULE;
 792         sysfs_attr_version_str.attr.owner = THIS_MODULE;
 793         rc = do_sysfs_registration();
 794         if (rc) {
 795                 printk(KERN_ERR "sysfs registration failed\n");
 796                 unregister_filesystem(&ecryptfs_fs_type);
 797                 ecryptfs_free_kmem_caches();
 798                 goto out;
 799         }
 800 out:
 801         return rc;
 802 }
 803
 804 static void __exit ecryptfs_exit(void)
 805 {
 806         sysfs_remove_file(&ecryptfs_subsys.kset.kobj,
 807                           &sysfs_attr_version.attr);
 808         sysfs_remove_file(&ecryptfs_subsys.kset.kobj,
 809                           &sysfs_attr_version_str.attr);
 810         subsystem_unregister(&ecryptfs_subsys);
 811         unregister_filesystem(&ecryptfs_fs_type);
 812         ecryptfs_free_kmem_caches();
 813 }
 814
 815 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 816 MODULE_DESCRIPTION("eCryptfs");
 817
 818 MODULE_LICENSE("GPL");
 819
 820 module_init(ecryptfs_init)
 821 module_exit(ecryptfs_exit)