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 <linux/fs_stack.h>
  39 #include "ecryptfs_kernel.h"
  40
  41 /**
  42  * Module parameter that defines the ecryptfs_verbosity level.
  43  */
  44 int ecryptfs_verbosity = 0;
  45
  46 module_param(ecryptfs_verbosity, int, 0);
  47 MODULE_PARM_DESC(ecryptfs_verbosity,
  48                  "Initial verbosity level (0 or 1; defaults to "
  49                  "0, which is Quiet)");
  50
  51 void __ecryptfs_printk(const char *fmt, ...)
  52 {
  53         va_list args;
  54         va_start(args, fmt);
  55         if (fmt[1] == '7') { /* KERN_DEBUG */
  56                 if (ecryptfs_verbosity >= 1)
  57                         vprintk(fmt, args);
  58         } else
  59                 vprintk(fmt, args);
  60         va_end(args);
  61 }
  62
  63 /**
  64  * ecryptfs_interpose
  65  * @lower_dentry: Existing dentry in the lower filesystem
  66  * @dentry: ecryptfs' dentry
  67  * @sb: ecryptfs's super_block
  68  * @flag: If set to true, then d_add is called, else d_instantiate is called
  69  *
  70  * Interposes upper and lower dentries.
  71  *
  72  * Returns zero on success; non-zero otherwise
  73  */
  74 int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
  75                        struct super_block *sb, int flag)
  76 {
  77         struct inode *lower_inode;
  78         struct inode *inode;
  79         int rc = 0;
  80
  81         lower_inode = lower_dentry->d_inode;
  82         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) {
  83                 rc = -EXDEV;
  84                 goto out;
  85         }
  86         if (!igrab(lower_inode)) {
  87                 rc = -ESTALE;
  88                 goto out;
  89         }
  90         inode = iget5_locked(sb, (unsigned long)lower_inode,
  91                              ecryptfs_inode_test, ecryptfs_inode_set,
  92                              lower_inode);
  93         if (!inode) {
  94                 rc = -EACCES;
  95                 iput(lower_inode);
  96                 goto out;
  97         }
  98         if (inode->i_state & I_NEW)
  99                 unlock_new_inode(inode);
 100         else
 101                 iput(lower_inode);
 102         if (S_ISLNK(lower_inode->i_mode))
 103                 inode->i_op = &ecryptfs_symlink_iops;
 104         else if (S_ISDIR(lower_inode->i_mode))
 105                 inode->i_op = &ecryptfs_dir_iops;
 106         if (S_ISDIR(lower_inode->i_mode))
 107                 inode->i_fop = &ecryptfs_dir_fops;
 108         if (special_file(lower_inode->i_mode))
 109                 init_special_inode(inode, lower_inode->i_mode,
 110                                    lower_inode->i_rdev);
 111         dentry->d_op = &ecryptfs_dops;
 112         if (flag)
 113                 d_add(dentry, inode);
 114         else
 115                 d_instantiate(dentry, inode);
 116         fsstack_copy_attr_all(inode, lower_inode, NULL);
 117         /* This size will be overwritten for real files w/ headers and
 118          * other metadata */
 119         fsstack_copy_inode_size(inode, lower_inode);
 120 out:
 121         return rc;
 122 }
 123
 124 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig, ecryptfs_opt_debug,
 125        ecryptfs_opt_ecryptfs_debug, ecryptfs_opt_cipher,
 126        ecryptfs_opt_ecryptfs_cipher, ecryptfs_opt_ecryptfs_key_bytes,
 127        ecryptfs_opt_passthrough, ecryptfs_opt_err };
 128
 129 static match_table_t tokens = {
 130         {ecryptfs_opt_sig, "sig=%s"},
 131         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 132         {ecryptfs_opt_debug, "debug=%u"},
 133         {ecryptfs_opt_ecryptfs_debug, "ecryptfs_debug=%u"},
 134         {ecryptfs_opt_cipher, "cipher=%s"},
 135         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
 136         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
 137         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
 138         {ecryptfs_opt_err, NULL}
 139 };
 140
 141 /**
 142  * ecryptfs_verify_version
 143  * @version: The version number to confirm
 144  *
 145  * Returns zero on good version; non-zero otherwise
 146  */
 147 static int ecryptfs_verify_version(u16 version)
 148 {
 149         int rc = 0;
 150         unsigned char major;
 151         unsigned char minor;
 152
 153         major = ((version >> 8) & 0xFF);
 154         minor = (version & 0xFF);
 155         if (major != ECRYPTFS_VERSION_MAJOR) {
 156                 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
 157                                 "Expected [%d]; got [%d]\n",
 158                                 ECRYPTFS_VERSION_MAJOR, major);
 159                 rc = -EINVAL;
 160                 goto out;
 161         }
 162         if (minor != ECRYPTFS_VERSION_MINOR) {
 163                 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
 164                                 "Expected [%d]; got [%d]\n",
 165                                 ECRYPTFS_VERSION_MINOR, minor);
 166                 rc = -EINVAL;
 167                 goto out;
 168         }
 169 out:
 170         return rc;
 171 }
 172
 173 /**
 174  * ecryptfs_parse_options
 175  * @sb: The ecryptfs super block
 176  * @options: The options pased to the kernel
 177  *
 178  * Parse mount options:
 179  * debug=N         - ecryptfs_verbosity level for debug output
 180  * sig=XXX         - description(signature) of the key to use
 181  *
 182  * Returns the dentry object of the lower-level (lower/interposed)
 183  * directory; We want to mount our stackable file system on top of
 184  * that lower directory.
 185  *
 186  * The signature of the key to use must be the description of a key
 187  * already in the keyring. Mounting will fail if the key can not be
 188  * found.
 189  *
 190  * Returns zero on success; non-zero on error
 191  */
 192 static int ecryptfs_parse_options(struct super_block *sb, char *options)
 193 {
 194         char *p;
 195         int rc = 0;
 196         int sig_set = 0;
 197         int cipher_name_set = 0;
 198         int cipher_key_bytes;
 199         int cipher_key_bytes_set = 0;
 200         struct key *auth_tok_key = NULL;
 201         struct ecryptfs_auth_tok *auth_tok = NULL;
 202         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 203                 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
 204         substring_t args[MAX_OPT_ARGS];
 205         int token;
 206         char *sig_src;
 207         char *sig_dst;
 208         char *debug_src;
 209         char *cipher_name_dst;
 210         char *cipher_name_src;
 211         char *cipher_key_bytes_src;
 212         int cipher_name_len;
 213
 214         if (!options) {
 215                 rc = -EINVAL;
 216                 goto out;
 217         }
 218         while ((p = strsep(&options, ",")) != NULL) {
 219                 if (!*p)
 220                         continue;
 221                 token = match_token(p, tokens, args);
 222                 switch (token) {
 223                 case ecryptfs_opt_sig:
 224                 case ecryptfs_opt_ecryptfs_sig:
 225                         sig_src = args[0].from;
 226                         sig_dst =
 227                                 mount_crypt_stat->global_auth_tok_sig;
 228                         memcpy(sig_dst, sig_src, ECRYPTFS_SIG_SIZE_HEX);
 229                         sig_dst[ECRYPTFS_SIG_SIZE_HEX] = '\0';
 230                         ecryptfs_printk(KERN_DEBUG,
 231                                         "The mount_crypt_stat "
 232                                         "global_auth_tok_sig set to: "
 233                                         "[%s]\n", sig_dst);
 234                         sig_set = 1;
 235                         break;
 236                 case ecryptfs_opt_debug:
 237                 case ecryptfs_opt_ecryptfs_debug:
 238                         debug_src = args[0].from;
 239                         ecryptfs_verbosity =
 240                                 (int)simple_strtol(debug_src, &debug_src,
 241                                                    0);
 242                         ecryptfs_printk(KERN_DEBUG,
 243                                         "Verbosity set to [%d]" "\n",
 244                                         ecryptfs_verbosity);
 245                         break;
 246                 case ecryptfs_opt_cipher:
 247                 case ecryptfs_opt_ecryptfs_cipher:
 248                         cipher_name_src = args[0].from;
 249                         cipher_name_dst =
 250                                 mount_crypt_stat->
 251                                 global_default_cipher_name;
 252                         strncpy(cipher_name_dst, cipher_name_src,
 253                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 254                         ecryptfs_printk(KERN_DEBUG,
 255                                         "The mount_crypt_stat "
 256                                         "global_default_cipher_name set to: "
 257                                         "[%s]\n", cipher_name_dst);
 258                         cipher_name_set = 1;
 259                         break;
 260                 case ecryptfs_opt_ecryptfs_key_bytes:
 261                         cipher_key_bytes_src = args[0].from;
 262                         cipher_key_bytes =
 263                                 (int)simple_strtol(cipher_key_bytes_src,
 264                                                    &cipher_key_bytes_src, 0);
 265                         mount_crypt_stat->global_default_cipher_key_size =
 266                                 cipher_key_bytes;
 267                         ecryptfs_printk(KERN_DEBUG,
 268                                         "The mount_crypt_stat "
 269                                         "global_default_cipher_key_size "
 270                                         "set to: [%d]\n", mount_crypt_stat->
 271                                         global_default_cipher_key_size);
 272                         cipher_key_bytes_set = 1;
 273                         break;
 274                 case ecryptfs_opt_passthrough:
 275                         mount_crypt_stat->flags |=
 276                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 277                         break;
 278                 case ecryptfs_opt_err:
 279                 default:
 280                         ecryptfs_printk(KERN_WARNING,
 281                                         "eCryptfs: unrecognized option '%s'\n",
 282                                         p);
 283                 }
 284         }
 285         /* Do not support lack of mount-wide signature in 0.1
 286          * release */
 287         if (!sig_set) {
 288                 rc = -EINVAL;
 289                 ecryptfs_printk(KERN_ERR, "You must supply a valid "
 290                                 "passphrase auth tok signature as a mount "
 291                                 "parameter; see the eCryptfs README\n");
 292                 goto out;
 293         }
 294         if (!cipher_name_set) {
 295                 cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 296                 if (unlikely(cipher_name_len
 297                              >= ECRYPTFS_MAX_CIPHER_NAME_SIZE)) {
 298                         rc = -EINVAL;
 299                         BUG();
 300                         goto out;
 301                 }
 302                 memcpy(mount_crypt_stat->global_default_cipher_name,
 303                        ECRYPTFS_DEFAULT_CIPHER, cipher_name_len);
 304                 mount_crypt_stat->global_default_cipher_name[cipher_name_len]
 305                     = '\0';
 306         }
 307         if (!cipher_key_bytes_set) {
 308                 mount_crypt_stat->global_default_cipher_key_size = 0;
 309         }
 310         rc = ecryptfs_process_cipher(
 311                 &mount_crypt_stat->global_key_tfm,
 312                 mount_crypt_stat->global_default_cipher_name,
 313                 &mount_crypt_stat->global_default_cipher_key_size);
 314         if (rc) {
 315                 printk(KERN_ERR "Error attempting to initialize cipher [%s] "
 316                        "with key size [%Zd] bytes; rc = [%d]\n",
 317                        mount_crypt_stat->global_default_cipher_name,
 318                        mount_crypt_stat->global_default_cipher_key_size, rc);
 319                 mount_crypt_stat->global_key_tfm = NULL;
 320                 mount_crypt_stat->global_auth_tok_key = NULL;
 321                 rc = -EINVAL;
 322                 goto out;
 323         }
 324         mutex_init(&mount_crypt_stat->global_key_tfm_mutex);
 325         ecryptfs_printk(KERN_DEBUG, "Requesting the key with description: "
 326                         "[%s]\n", mount_crypt_stat->global_auth_tok_sig);
 327         /* The reference to this key is held until umount is done The
 328          * call to key_put is done in ecryptfs_put_super() */
 329         auth_tok_key = request_key(&key_type_user,
 330                                    mount_crypt_stat->global_auth_tok_sig,
 331                                    NULL);
 332         if (!auth_tok_key || IS_ERR(auth_tok_key)) {
 333                 ecryptfs_printk(KERN_ERR, "Could not find key with "
 334                                 "description: [%s]\n",
 335                                 mount_crypt_stat->global_auth_tok_sig);
 336                 process_request_key_err(PTR_ERR(auth_tok_key));
 337                 rc = -EINVAL;
 338                 goto out;
 339         }
 340         auth_tok = ecryptfs_get_key_payload_data(auth_tok_key);
 341         if (ecryptfs_verify_version(auth_tok->version)) {
 342                 ecryptfs_printk(KERN_ERR, "Data structure version mismatch. "
 343                                 "Userspace tools must match eCryptfs kernel "
 344                                 "module with major version [%d] and minor "
 345                                 "version [%d]\n", ECRYPTFS_VERSION_MAJOR,
 346                                 ECRYPTFS_VERSION_MINOR);
 347                 rc = -EINVAL;
 348                 goto out;
 349         }
 350         if (auth_tok->token_type != ECRYPTFS_PASSWORD) {
 351                 ecryptfs_printk(KERN_ERR, "Invalid auth_tok structure "
 352                                 "returned from key\n");
 353                 rc = -EINVAL;
 354                 goto out;
 355         }
 356         mount_crypt_stat->global_auth_tok_key = auth_tok_key;
 357         mount_crypt_stat->global_auth_tok = auth_tok;
 358 out:
 359         return rc;
 360 }
 361
 362 struct kmem_cache *ecryptfs_sb_info_cache;
 363
 364 /**
 365  * ecryptfs_fill_super
 366  * @sb: The ecryptfs super block
 367  * @raw_data: The options passed to mount
 368  * @silent: Not used but required by function prototype
 369  *
 370  * Sets up what we can of the sb, rest is done in ecryptfs_read_super
 371  *
 372  * Returns zero on success; non-zero otherwise
 373  */
 374 static int
 375 ecryptfs_fill_super(struct super_block *sb, void *raw_data, int silent)
 376 {
 377         int rc = 0;
 378
 379         /* Released in ecryptfs_put_super() */
 380         ecryptfs_set_superblock_private(sb,
 381                                         kmem_cache_alloc(ecryptfs_sb_info_cache,
 382                                                          GFP_KERNEL));
 383         if (!ecryptfs_superblock_to_private(sb)) {
 384                 ecryptfs_printk(KERN_WARNING, "Out of memory\n");
 385                 rc = -ENOMEM;
 386                 goto out;
 387         }
 388         memset(ecryptfs_superblock_to_private(sb), 0,
 389                sizeof(struct ecryptfs_sb_info));
 390         sb->s_op = &ecryptfs_sops;
 391         /* Released through deactivate_super(sb) from get_sb_nodev */
 392         sb->s_root = d_alloc(NULL, &(const struct qstr) {
 393                              .hash = 0,.name = "/",.len = 1});
 394         if (!sb->s_root) {
 395                 ecryptfs_printk(KERN_ERR, "d_alloc failed\n");
 396                 rc = -ENOMEM;
 397                 goto out;
 398         }
 399         sb->s_root->d_op = &ecryptfs_dops;
 400         sb->s_root->d_sb = sb;
 401         sb->s_root->d_parent = sb->s_root;
 402         /* Released in d_release when dput(sb->s_root) is called */
 403         /* through deactivate_super(sb) from get_sb_nodev() */
 404         ecryptfs_set_dentry_private(sb->s_root,
 405                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
 406                                                      GFP_KERNEL));
 407         if (!ecryptfs_dentry_to_private(sb->s_root)) {
 408                 ecryptfs_printk(KERN_ERR,
 409                                 "dentry_info_cache alloc failed\n");
 410                 rc = -ENOMEM;
 411                 goto out;
 412         }
 413         memset(ecryptfs_dentry_to_private(sb->s_root), 0,
 414                sizeof(struct ecryptfs_dentry_info));
 415         rc = 0;
 416 out:
 417         /* Should be able to rely on deactivate_super called from
 418          * get_sb_nodev */
 419         return rc;
 420 }
 421
 422 /**
 423  * ecryptfs_read_super
 424  * @sb: The ecryptfs super block
 425  * @dev_name: The path to mount over
 426  *
 427  * Read the super block of the lower filesystem, and use
 428  * ecryptfs_interpose to create our initial inode and super block
 429  * struct.
 430  */
 431 static int ecryptfs_read_super(struct super_block *sb, const char *dev_name)
 432 {
 433         int rc;
 434         struct nameidata nd;
 435         struct dentry *lower_root;
 436         struct vfsmount *lower_mnt;
 437
 438         memset(&nd, 0, sizeof(struct nameidata));
 439         rc = path_lookup(dev_name, LOOKUP_FOLLOW, &nd);
 440         if (rc) {
 441                 ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n");
 442                 goto out_free;
 443         }
 444         lower_root = nd.dentry;
 445         if (!lower_root->d_inode) {
 446                 ecryptfs_printk(KERN_WARNING,
 447                                 "No directory to interpose on\n");
 448                 rc = -ENOENT;
 449                 goto out_free;
 450         }
 451         lower_mnt = nd.mnt;
 452         ecryptfs_set_superblock_lower(sb, lower_root->d_sb);
 453         sb->s_maxbytes = lower_root->d_sb->s_maxbytes;
 454         ecryptfs_set_dentry_lower(sb->s_root, lower_root);
 455         ecryptfs_set_dentry_lower_mnt(sb->s_root, lower_mnt);
 456         if ((rc = ecryptfs_interpose(lower_root, sb->s_root, sb, 0)))
 457                 goto out_free;
 458         rc = 0;
 459         goto out;
 460 out_free:
 461         path_release(&nd);
 462 out:
 463         return rc;
 464 }
 465
 466 /**
 467  * ecryptfs_get_sb
 468  * @fs_type
 469  * @flags
 470  * @dev_name: The path to mount over
 471  * @raw_data: The options passed into the kernel
 472  *
 473  * The whole ecryptfs_get_sb process is broken into 4 functions:
 474  * ecryptfs_parse_options(): handle options passed to ecryptfs, if any
 475  * ecryptfs_fill_super(): used by get_sb_nodev, fills out the super_block
 476  *                        with as much information as it can before needing
 477  *                        the lower filesystem.
 478  * ecryptfs_read_super(): this accesses the lower filesystem and uses
 479  *                        ecryptfs_interpolate to perform most of the linking
 480  * ecryptfs_interpolate(): links the lower filesystem into ecryptfs
 481  */
 482 static int ecryptfs_get_sb(struct file_system_type *fs_type, int flags,
 483                         const char *dev_name, void *raw_data,
 484                         struct vfsmount *mnt)
 485 {
 486         int rc;
 487         struct super_block *sb;
 488
 489         rc = get_sb_nodev(fs_type, flags, raw_data, ecryptfs_fill_super, mnt);
 490         if (rc < 0) {
 491                 printk(KERN_ERR "Getting sb failed; rc = [%d]\n", rc);
 492                 goto out;
 493         }
 494         sb = mnt->mnt_sb;
 495         rc = ecryptfs_parse_options(sb, raw_data);
 496         if (rc) {
 497                 printk(KERN_ERR "Error parsing options; rc = [%d]\n", rc);
 498                 goto out_abort;
 499         }
 500         rc = ecryptfs_read_super(sb, dev_name);
 501         if (rc) {
 502                 printk(KERN_ERR "Reading sb failed; rc = [%d]\n", rc);
 503                 goto out_abort;
 504         }
 505         goto out;
 506 out_abort:
 507         dput(sb->s_root);
 508         up_write(&sb->s_umount);
 509         deactivate_super(sb);
 510 out:
 511         return rc;
 512 }
 513
 514 /**
 515  * ecryptfs_kill_block_super
 516  * @sb: The ecryptfs super block
 517  *
 518  * Used to bring the superblock down and free the private data.
 519  * Private data is free'd in ecryptfs_put_super()
 520  */
 521 static void ecryptfs_kill_block_super(struct super_block *sb)
 522 {
 523         generic_shutdown_super(sb);
 524 }
 525
 526 static struct file_system_type ecryptfs_fs_type = {
 527         .owner = THIS_MODULE,
 528         .name = "ecryptfs",
 529         .get_sb = ecryptfs_get_sb,
 530         .kill_sb = ecryptfs_kill_block_super,
 531         .fs_flags = 0
 532 };
 533
 534 /**
 535  * inode_info_init_once
 536  *
 537  * Initializes the ecryptfs_inode_info_cache when it is created
 538  */
 539 static void
 540 inode_info_init_once(void *vptr, struct kmem_cache *cachep, unsigned long flags)
 541 {
 542         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 543
 544         if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) ==
 545             SLAB_CTOR_CONSTRUCTOR)
 546                 inode_init_once(&ei->vfs_inode);
 547 }
 548
 549 static struct ecryptfs_cache_info {
 550         struct kmem_cache **cache;
 551         const char *name;
 552         size_t size;
 553         void (*ctor)(void*, struct kmem_cache *, unsigned long);
 554 } ecryptfs_cache_infos[] = {
 555         {
 556                 .cache = &ecryptfs_auth_tok_list_item_cache,
 557                 .name = "ecryptfs_auth_tok_list_item",
 558                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 559         },
 560         {
 561                 .cache = &ecryptfs_file_info_cache,
 562                 .name = "ecryptfs_file_cache",
 563                 .size = sizeof(struct ecryptfs_file_info),
 564         },
 565         {
 566                 .cache = &ecryptfs_dentry_info_cache,
 567                 .name = "ecryptfs_dentry_info_cache",
 568                 .size = sizeof(struct ecryptfs_dentry_info),
 569         },
 570         {
 571                 .cache = &ecryptfs_inode_info_cache,
 572                 .name = "ecryptfs_inode_cache",
 573                 .size = sizeof(struct ecryptfs_inode_info),
 574                 .ctor = inode_info_init_once,
 575         },
 576         {
 577                 .cache = &ecryptfs_sb_info_cache,
 578                 .name = "ecryptfs_sb_cache",
 579                 .size = sizeof(struct ecryptfs_sb_info),
 580         },
 581         {
 582                 .cache = &ecryptfs_header_cache_0,
 583                 .name = "ecryptfs_headers_0",
 584                 .size = PAGE_CACHE_SIZE,
 585         },
 586         {
 587                 .cache = &ecryptfs_header_cache_1,
 588                 .name = "ecryptfs_headers_1",
 589                 .size = PAGE_CACHE_SIZE,
 590         },
 591         {
 592                 .cache = &ecryptfs_header_cache_2,
 593                 .name = "ecryptfs_headers_2",
 594                 .size = PAGE_CACHE_SIZE,
 595         },
 596         {
 597                 .cache = &ecryptfs_lower_page_cache,
 598                 .name = "ecryptfs_lower_page_cache",
 599                 .size = PAGE_CACHE_SIZE,
 600         },
 601 };
 602
 603 static void ecryptfs_free_kmem_caches(void)
 604 {
 605         int i;
 606
 607         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 608                 struct ecryptfs_cache_info *info;
 609
 610                 info = &ecryptfs_cache_infos[i];
 611                 if (*(info->cache))
 612                         kmem_cache_destroy(*(info->cache));
 613         }
 614 }
 615
 616 /**
 617  * ecryptfs_init_kmem_caches
 618  *
 619  * Returns zero on success; non-zero otherwise
 620  */
 621 static int ecryptfs_init_kmem_caches(void)
 622 {
 623         int i;
 624
 625         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 626                 struct ecryptfs_cache_info *info;
 627
 628                 info = &ecryptfs_cache_infos[i];
 629                 *(info->cache) = kmem_cache_create(info->name, info->size,
 630                                 0, SLAB_HWCACHE_ALIGN, info->ctor, NULL);
 631                 if (!*(info->cache)) {
 632                         ecryptfs_free_kmem_caches();
 633                         ecryptfs_printk(KERN_WARNING, "%s: "
 634                                         "kmem_cache_create failed\n",
 635                                         info->name);
 636                         return -ENOMEM;
 637                 }
 638         }
 639         return 0;
 640 }
 641
 642 struct ecryptfs_obj {
 643         char *name;
 644         struct list_head slot_list;
 645         struct kobject kobj;
 646 };
 647
 648 struct ecryptfs_attribute {
 649         struct attribute attr;
 650         ssize_t(*show) (struct ecryptfs_obj *, char *);
 651         ssize_t(*store) (struct ecryptfs_obj *, const char *, size_t);
 652 };
 653
 654 static ssize_t
 655 ecryptfs_attr_store(struct kobject *kobj,
 656                     struct attribute *attr, const char *buf, size_t len)
 657 {
 658         struct ecryptfs_obj *obj = container_of(kobj, struct ecryptfs_obj,
 659                                                 kobj);
 660         struct ecryptfs_attribute *attribute =
 661                 container_of(attr, struct ecryptfs_attribute, attr);
 662
 663         return (attribute->store ? attribute->store(obj, buf, len) : 0);
 664 }
 665
 666 static ssize_t
 667 ecryptfs_attr_show(struct kobject *kobj, struct attribute *attr, char *buf)
 668 {
 669         struct ecryptfs_obj *obj = container_of(kobj, struct ecryptfs_obj,
 670                                                 kobj);
 671         struct ecryptfs_attribute *attribute =
 672                 container_of(attr, struct ecryptfs_attribute, attr);
 673
 674         return (attribute->show ? attribute->show(obj, buf) : 0);
 675 }
 676
 677 static struct sysfs_ops ecryptfs_sysfs_ops = {
 678         .show = ecryptfs_attr_show,
 679         .store = ecryptfs_attr_store
 680 };
 681
 682 static struct kobj_type ecryptfs_ktype = {
 683         .sysfs_ops = &ecryptfs_sysfs_ops
 684 };
 685
 686 static decl_subsys(ecryptfs, &ecryptfs_ktype, NULL);
 687
 688 static ssize_t version_show(struct ecryptfs_obj *obj, char *buff)
 689 {
 690         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 691 }
 692
 693 static struct ecryptfs_attribute sysfs_attr_version = __ATTR_RO(version);
 694
 695 static struct ecryptfs_version_str_map_elem {
 696         u32 flag;
 697         char *str;
 698 } ecryptfs_version_str_map[] = {
 699         {ECRYPTFS_VERSIONING_PASSPHRASE, "passphrase"},
 700         {ECRYPTFS_VERSIONING_PUBKEY, "pubkey"},
 701         {ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH, "plaintext passthrough"},
 702         {ECRYPTFS_VERSIONING_POLICY, "policy"}
 703 };
 704
 705 static ssize_t version_str_show(struct ecryptfs_obj *obj, char *buff)
 706 {
 707         int i;
 708         int remaining = PAGE_SIZE;
 709         int total_written = 0;
 710
 711         buff[0] = '\0';
 712         for (i = 0; i < ARRAY_SIZE(ecryptfs_version_str_map); i++) {
 713                 int entry_size;
 714
 715                 if (!(ECRYPTFS_VERSIONING_MASK
 716                       & ecryptfs_version_str_map[i].flag))
 717                         continue;
 718                 entry_size = strlen(ecryptfs_version_str_map[i].str);
 719                 if ((entry_size + 2) > remaining)
 720                         goto out;
 721                 memcpy(buff, ecryptfs_version_str_map[i].str, entry_size);
 722                 buff[entry_size++] = '\n';
 723                 buff[entry_size] = '\0';
 724                 buff += entry_size;
 725                 total_written += entry_size;
 726                 remaining -= entry_size;
 727         }
 728 out:
 729         return total_written;
 730 }
 731
 732 static struct ecryptfs_attribute sysfs_attr_version_str = __ATTR_RO(version_str);
 733
 734 static int do_sysfs_registration(void)
 735 {
 736         int rc;
 737
 738         if ((rc = subsystem_register(&ecryptfs_subsys))) {
 739                 printk(KERN_ERR
 740                        "Unable to register ecryptfs sysfs subsystem\n");
 741                 goto out;
 742         }
 743         rc = sysfs_create_file(&ecryptfs_subsys.kset.kobj,
 744                                &sysfs_attr_version.attr);
 745         if (rc) {
 746                 printk(KERN_ERR
 747                        "Unable to create ecryptfs version attribute\n");
 748                 subsystem_unregister(&ecryptfs_subsys);
 749                 goto out;
 750         }
 751         rc = sysfs_create_file(&ecryptfs_subsys.kset.kobj,
 752                                &sysfs_attr_version_str.attr);
 753         if (rc) {
 754                 printk(KERN_ERR
 755                        "Unable to create ecryptfs version_str attribute\n");
 756                 sysfs_remove_file(&ecryptfs_subsys.kset.kobj,
 757                                   &sysfs_attr_version.attr);
 758                 subsystem_unregister(&ecryptfs_subsys);
 759                 goto out;
 760         }
 761 out:
 762         return rc;
 763 }
 764
 765 static int __init ecryptfs_init(void)
 766 {
 767         int rc;
 768
 769         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
 770                 rc = -EINVAL;
 771                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 772                                 "larger than the host's page size, and so "
 773                                 "eCryptfs cannot run on this system. The "
 774                                 "default eCryptfs extent size is [%d] bytes; "
 775                                 "the page size is [%d] bytes.\n",
 776                                 ECRYPTFS_DEFAULT_EXTENT_SIZE, PAGE_CACHE_SIZE);
 777                 goto out;
 778         }
 779         rc = ecryptfs_init_kmem_caches();
 780         if (rc) {
 781                 printk(KERN_ERR
 782                        "Failed to allocate one or more kmem_cache objects\n");
 783                 goto out;
 784         }
 785         rc = register_filesystem(&ecryptfs_fs_type);
 786         if (rc) {
 787                 printk(KERN_ERR "Failed to register filesystem\n");
 788                 ecryptfs_free_kmem_caches();
 789                 goto out;
 790         }
 791         kset_set_kset_s(&ecryptfs_subsys, fs_subsys);
 792         sysfs_attr_version.attr.owner = THIS_MODULE;
 793         sysfs_attr_version_str.attr.owner = THIS_MODULE;
 794         rc = do_sysfs_registration();
 795         if (rc) {
 796                 printk(KERN_ERR "sysfs registration failed\n");
 797                 unregister_filesystem(&ecryptfs_fs_type);
 798                 ecryptfs_free_kmem_caches();
 799                 goto out;
 800         }
 801 out:
 802         return rc;
 803 }
 804
 805 static void __exit ecryptfs_exit(void)
 806 {
 807         sysfs_remove_file(&ecryptfs_subsys.kset.kobj,
 808                           &sysfs_attr_version.attr);
 809         sysfs_remove_file(&ecryptfs_subsys.kset.kobj,
 810                           &sysfs_attr_version_str.attr);
 811         subsystem_unregister(&ecryptfs_subsys);
 812         unregister_filesystem(&ecryptfs_fs_type);
 813         ecryptfs_free_kmem_caches();
 814 }
 815
 816 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 817 MODULE_DESCRIPTION("eCryptfs");
 818
 819 MODULE_LICENSE("GPL");
 820
 821 module_init(ecryptfs_init)
 822 module_exit(ecryptfs_exit)