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/netlink.h>
  34 #include <linux/mount.h>
  35 #include <linux/dcache.h>
  36 #include <linux/pagemap.h>
  37 #include <linux/key.h>
  38 #include <linux/parser.h>
  39 #include <linux/fs_stack.h>
  40 #include "ecryptfs_kernel.h"
  41
  42 /**
  43  * Module parameter that defines the ecryptfs_verbosity level.
  44  */
  45 int ecryptfs_verbosity = 0;
  46
  47 module_param(ecryptfs_verbosity, int, 0);
  48 MODULE_PARM_DESC(ecryptfs_verbosity,
  49                  "Initial verbosity level (0 or 1; defaults to "
  50                  "0, which is Quiet)");
  51
  52 /**
  53  * Module parameter that defines the number of netlink message buffer
  54  * elements
  55  */
  56 unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
  57
  58 module_param(ecryptfs_message_buf_len, uint, 0);
  59 MODULE_PARM_DESC(ecryptfs_message_buf_len,
  60                  "Number of message buffer elements");
  61
  62 /**
  63  * Module parameter that defines the maximum guaranteed amount of time to wait
  64  * for a response through netlink.  The actual sleep time will be, more than
  65  * likely, a small amount greater than this specified value, but only less if
  66  * the netlink message successfully arrives.
  67  */
  68 signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
  69
  70 module_param(ecryptfs_message_wait_timeout, long, 0);
  71 MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
  72                  "Maximum number of seconds that an operation will "
  73                  "sleep while waiting for a message response from "
  74                  "userspace");
  75
  76 /**
  77  * Module parameter that is an estimate of the maximum number of users
  78  * that will be concurrently using eCryptfs. Set this to the right
  79  * value to balance performance and memory use.
  80  */
  81 unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
  82
  83 module_param(ecryptfs_number_of_users, uint, 0);
  84 MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
  85                  "concurrent users of eCryptfs");
  86
  87 unsigned int ecryptfs_transport = ECRYPTFS_DEFAULT_TRANSPORT;
  88
  89 void __ecryptfs_printk(const char *fmt, ...)
  90 {
  91         va_list args;
  92         va_start(args, fmt);
  93         if (fmt[1] == '7') { /* KERN_DEBUG */
  94                 if (ecryptfs_verbosity >= 1)
  95                         vprintk(fmt, args);
  96         } else
  97                 vprintk(fmt, args);
  98         va_end(args);
  99 }
 100
 101 /**
 102  * ecryptfs_interpose
 103  * @lower_dentry: Existing dentry in the lower filesystem
 104  * @dentry: ecryptfs' dentry
 105  * @sb: ecryptfs's super_block
 106  * @flag: If set to true, then d_add is called, else d_instantiate is called
 107  *
 108  * Interposes upper and lower dentries.
 109  *
 110  * Returns zero on success; non-zero otherwise
 111  */
 112 int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
 113                        struct super_block *sb, int flag)
 114 {
 115         struct inode *lower_inode;
 116         struct inode *inode;
 117         int rc = 0;
 118
 119         lower_inode = lower_dentry->d_inode;
 120         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) {
 121                 rc = -EXDEV;
 122                 goto out;
 123         }
 124         if (!igrab(lower_inode)) {
 125                 rc = -ESTALE;
 126                 goto out;
 127         }
 128         inode = iget5_locked(sb, (unsigned long)lower_inode,
 129                              ecryptfs_inode_test, ecryptfs_inode_set,
 130                              lower_inode);
 131         if (!inode) {
 132                 rc = -EACCES;
 133                 iput(lower_inode);
 134                 goto out;
 135         }
 136         if (inode->i_state & I_NEW)
 137                 unlock_new_inode(inode);
 138         else
 139                 iput(lower_inode);
 140         if (S_ISLNK(lower_inode->i_mode))
 141                 inode->i_op = &ecryptfs_symlink_iops;
 142         else if (S_ISDIR(lower_inode->i_mode))
 143                 inode->i_op = &ecryptfs_dir_iops;
 144         if (S_ISDIR(lower_inode->i_mode))
 145                 inode->i_fop = &ecryptfs_dir_fops;
 146         if (special_file(lower_inode->i_mode))
 147                 init_special_inode(inode, lower_inode->i_mode,
 148                                    lower_inode->i_rdev);
 149         dentry->d_op = &ecryptfs_dops;
 150         if (flag)
 151                 d_add(dentry, inode);
 152         else
 153                 d_instantiate(dentry, inode);
 154         fsstack_copy_attr_all(inode, lower_inode, NULL);
 155         /* This size will be overwritten for real files w/ headers and
 156          * other metadata */
 157         fsstack_copy_inode_size(inode, lower_inode);
 158 out:
 159         return rc;
 160 }
 161
 162 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig, ecryptfs_opt_debug,
 163        ecryptfs_opt_ecryptfs_debug, ecryptfs_opt_cipher,
 164        ecryptfs_opt_ecryptfs_cipher, ecryptfs_opt_ecryptfs_key_bytes,
 165        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
 166        ecryptfs_opt_encrypted_view, ecryptfs_opt_err };
 167
 168 static match_table_t tokens = {
 169         {ecryptfs_opt_sig, "sig=%s"},
 170         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 171         {ecryptfs_opt_debug, "debug=%u"},
 172         {ecryptfs_opt_ecryptfs_debug, "ecryptfs_debug=%u"},
 173         {ecryptfs_opt_cipher, "cipher=%s"},
 174         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
 175         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
 176         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
 177         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
 178         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
 179         {ecryptfs_opt_err, NULL}
 180 };
 181
 182 /**
 183  * ecryptfs_verify_version
 184  * @version: The version number to confirm
 185  *
 186  * Returns zero on good version; non-zero otherwise
 187  */
 188 static int ecryptfs_verify_version(u16 version)
 189 {
 190         int rc = 0;
 191         unsigned char major;
 192         unsigned char minor;
 193
 194         major = ((version >> 8) & 0xFF);
 195         minor = (version & 0xFF);
 196         if (major != ECRYPTFS_VERSION_MAJOR) {
 197                 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
 198                                 "Expected [%d]; got [%d]\n",
 199                                 ECRYPTFS_VERSION_MAJOR, major);
 200                 rc = -EINVAL;
 201                 goto out;
 202         }
 203         if (minor != ECRYPTFS_VERSION_MINOR) {
 204                 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
 205                                 "Expected [%d]; got [%d]\n",
 206                                 ECRYPTFS_VERSION_MINOR, minor);
 207                 rc = -EINVAL;
 208                 goto out;
 209         }
 210 out:
 211         return rc;
 212 }
 213
 214 /**
 215  * ecryptfs_parse_options
 216  * @sb: The ecryptfs super block
 217  * @options: The options pased to the kernel
 218  *
 219  * Parse mount options:
 220  * debug=N         - ecryptfs_verbosity level for debug output
 221  * sig=XXX         - description(signature) of the key to use
 222  *
 223  * Returns the dentry object of the lower-level (lower/interposed)
 224  * directory; We want to mount our stackable file system on top of
 225  * that lower directory.
 226  *
 227  * The signature of the key to use must be the description of a key
 228  * already in the keyring. Mounting will fail if the key can not be
 229  * found.
 230  *
 231  * Returns zero on success; non-zero on error
 232  */
 233 static int ecryptfs_parse_options(struct super_block *sb, char *options)
 234 {
 235         char *p;
 236         int rc = 0;
 237         int sig_set = 0;
 238         int cipher_name_set = 0;
 239         int cipher_key_bytes;
 240         int cipher_key_bytes_set = 0;
 241         struct key *auth_tok_key = NULL;
 242         struct ecryptfs_auth_tok *auth_tok = NULL;
 243         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 244                 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
 245         substring_t args[MAX_OPT_ARGS];
 246         int token;
 247         char *sig_src;
 248         char *sig_dst;
 249         char *debug_src;
 250         char *cipher_name_dst;
 251         char *cipher_name_src;
 252         char *cipher_key_bytes_src;
 253         int cipher_name_len;
 254
 255         if (!options) {
 256                 rc = -EINVAL;
 257                 goto out;
 258         }
 259         while ((p = strsep(&options, ",")) != NULL) {
 260                 if (!*p)
 261                         continue;
 262                 token = match_token(p, tokens, args);
 263                 switch (token) {
 264                 case ecryptfs_opt_sig:
 265                 case ecryptfs_opt_ecryptfs_sig:
 266                         sig_src = args[0].from;
 267                         sig_dst =
 268                                 mount_crypt_stat->global_auth_tok_sig;
 269                         memcpy(sig_dst, sig_src, ECRYPTFS_SIG_SIZE_HEX);
 270                         sig_dst[ECRYPTFS_SIG_SIZE_HEX] = '\0';
 271                         ecryptfs_printk(KERN_DEBUG,
 272                                         "The mount_crypt_stat "
 273                                         "global_auth_tok_sig set to: "
 274                                         "[%s]\n", sig_dst);
 275                         sig_set = 1;
 276                         break;
 277                 case ecryptfs_opt_debug:
 278                 case ecryptfs_opt_ecryptfs_debug:
 279                         debug_src = args[0].from;
 280                         ecryptfs_verbosity =
 281                                 (int)simple_strtol(debug_src, &debug_src,
 282                                                    0);
 283                         ecryptfs_printk(KERN_DEBUG,
 284                                         "Verbosity set to [%d]" "\n",
 285                                         ecryptfs_verbosity);
 286                         break;
 287                 case ecryptfs_opt_cipher:
 288                 case ecryptfs_opt_ecryptfs_cipher:
 289                         cipher_name_src = args[0].from;
 290                         cipher_name_dst =
 291                                 mount_crypt_stat->
 292                                 global_default_cipher_name;
 293                         strncpy(cipher_name_dst, cipher_name_src,
 294                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 295                         ecryptfs_printk(KERN_DEBUG,
 296                                         "The mount_crypt_stat "
 297                                         "global_default_cipher_name set to: "
 298                                         "[%s]\n", cipher_name_dst);
 299                         cipher_name_set = 1;
 300                         break;
 301                 case ecryptfs_opt_ecryptfs_key_bytes:
 302                         cipher_key_bytes_src = args[0].from;
 303                         cipher_key_bytes =
 304                                 (int)simple_strtol(cipher_key_bytes_src,
 305                                                    &cipher_key_bytes_src, 0);
 306                         mount_crypt_stat->global_default_cipher_key_size =
 307                                 cipher_key_bytes;
 308                         ecryptfs_printk(KERN_DEBUG,
 309                                         "The mount_crypt_stat "
 310                                         "global_default_cipher_key_size "
 311                                         "set to: [%d]\n", mount_crypt_stat->
 312                                         global_default_cipher_key_size);
 313                         cipher_key_bytes_set = 1;
 314                         break;
 315                 case ecryptfs_opt_passthrough:
 316                         mount_crypt_stat->flags |=
 317                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 318                         break;
 319                 case ecryptfs_opt_xattr_metadata:
 320                         mount_crypt_stat->flags |=
 321                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 322                         break;
 323                 case ecryptfs_opt_encrypted_view:
 324                         mount_crypt_stat->flags |=
 325                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 326                         mount_crypt_stat->flags |=
 327                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 328                         break;
 329                 case ecryptfs_opt_err:
 330                 default:
 331                         ecryptfs_printk(KERN_WARNING,
 332                                         "eCryptfs: unrecognized option '%s'\n",
 333                                         p);
 334                 }
 335         }
 336         /* Do not support lack of mount-wide signature in 0.1
 337          * release */
 338         if (!sig_set) {
 339                 rc = -EINVAL;
 340                 ecryptfs_printk(KERN_ERR, "You must supply a valid "
 341                                 "passphrase auth tok signature as a mount "
 342                                 "parameter; see the eCryptfs README\n");
 343                 goto out;
 344         }
 345         if (!cipher_name_set) {
 346                 cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 347                 if (unlikely(cipher_name_len
 348                              >= ECRYPTFS_MAX_CIPHER_NAME_SIZE)) {
 349                         rc = -EINVAL;
 350                         BUG();
 351                         goto out;
 352                 }
 353                 memcpy(mount_crypt_stat->global_default_cipher_name,
 354                        ECRYPTFS_DEFAULT_CIPHER, cipher_name_len);
 355                 mount_crypt_stat->global_default_cipher_name[cipher_name_len]
 356                     = '\0';
 357         }
 358         if (!cipher_key_bytes_set) {
 359                 mount_crypt_stat->global_default_cipher_key_size = 0;
 360         }
 361         rc = ecryptfs_process_cipher(
 362                 &mount_crypt_stat->global_key_tfm,
 363                 mount_crypt_stat->global_default_cipher_name,
 364                 &mount_crypt_stat->global_default_cipher_key_size);
 365         if (rc) {
 366                 printk(KERN_ERR "Error attempting to initialize cipher [%s] "
 367                        "with key size [%Zd] bytes; rc = [%d]\n",
 368                        mount_crypt_stat->global_default_cipher_name,
 369                        mount_crypt_stat->global_default_cipher_key_size, rc);
 370                 mount_crypt_stat->global_key_tfm = NULL;
 371                 mount_crypt_stat->global_auth_tok_key = NULL;
 372                 rc = -EINVAL;
 373                 goto out;
 374         }
 375         mutex_init(&mount_crypt_stat->global_key_tfm_mutex);
 376         ecryptfs_printk(KERN_DEBUG, "Requesting the key with description: "
 377                         "[%s]\n", mount_crypt_stat->global_auth_tok_sig);
 378         /* The reference to this key is held until umount is done The
 379          * call to key_put is done in ecryptfs_put_super() */
 380         auth_tok_key = request_key(&key_type_user,
 381                                    mount_crypt_stat->global_auth_tok_sig,
 382                                    NULL);
 383         if (!auth_tok_key || IS_ERR(auth_tok_key)) {
 384                 ecryptfs_printk(KERN_ERR, "Could not find key with "
 385                                 "description: [%s]\n",
 386                                 mount_crypt_stat->global_auth_tok_sig);
 387                 process_request_key_err(PTR_ERR(auth_tok_key));
 388                 rc = -EINVAL;
 389                 goto out;
 390         }
 391         auth_tok = ecryptfs_get_key_payload_data(auth_tok_key);
 392         if (ecryptfs_verify_version(auth_tok->version)) {
 393                 ecryptfs_printk(KERN_ERR, "Data structure version mismatch. "
 394                                 "Userspace tools must match eCryptfs kernel "
 395                                 "module with major version [%d] and minor "
 396                                 "version [%d]\n", ECRYPTFS_VERSION_MAJOR,
 397                                 ECRYPTFS_VERSION_MINOR);
 398                 rc = -EINVAL;
 399                 goto out;
 400         }
 401         if (auth_tok->token_type != ECRYPTFS_PASSWORD
 402             && auth_tok->token_type != ECRYPTFS_PRIVATE_KEY) {
 403                 ecryptfs_printk(KERN_ERR, "Invalid auth_tok structure "
 404                                 "returned from key query\n");
 405                 rc = -EINVAL;
 406                 goto out;
 407         }
 408         mount_crypt_stat->global_auth_tok_key = auth_tok_key;
 409         mount_crypt_stat->global_auth_tok = auth_tok;
 410 out:
 411         return rc;
 412 }
 413
 414 struct kmem_cache *ecryptfs_sb_info_cache;
 415
 416 /**
 417  * ecryptfs_fill_super
 418  * @sb: The ecryptfs super block
 419  * @raw_data: The options passed to mount
 420  * @silent: Not used but required by function prototype
 421  *
 422  * Sets up what we can of the sb, rest is done in ecryptfs_read_super
 423  *
 424  * Returns zero on success; non-zero otherwise
 425  */
 426 static int
 427 ecryptfs_fill_super(struct super_block *sb, void *raw_data, int silent)
 428 {
 429         int rc = 0;
 430
 431         /* Released in ecryptfs_put_super() */
 432         ecryptfs_set_superblock_private(sb,
 433                                         kmem_cache_zalloc(ecryptfs_sb_info_cache,
 434                                                          GFP_KERNEL));
 435         if (!ecryptfs_superblock_to_private(sb)) {
 436                 ecryptfs_printk(KERN_WARNING, "Out of memory\n");
 437                 rc = -ENOMEM;
 438                 goto out;
 439         }
 440         sb->s_op = &ecryptfs_sops;
 441         /* Released through deactivate_super(sb) from get_sb_nodev */
 442         sb->s_root = d_alloc(NULL, &(const struct qstr) {
 443                              .hash = 0,.name = "/",.len = 1});
 444         if (!sb->s_root) {
 445                 ecryptfs_printk(KERN_ERR, "d_alloc failed\n");
 446                 rc = -ENOMEM;
 447                 goto out;
 448         }
 449         sb->s_root->d_op = &ecryptfs_dops;
 450         sb->s_root->d_sb = sb;
 451         sb->s_root->d_parent = sb->s_root;
 452         /* Released in d_release when dput(sb->s_root) is called */
 453         /* through deactivate_super(sb) from get_sb_nodev() */
 454         ecryptfs_set_dentry_private(sb->s_root,
 455                                     kmem_cache_zalloc(ecryptfs_dentry_info_cache,
 456                                                      GFP_KERNEL));
 457         if (!ecryptfs_dentry_to_private(sb->s_root)) {
 458                 ecryptfs_printk(KERN_ERR,
 459                                 "dentry_info_cache alloc failed\n");
 460                 rc = -ENOMEM;
 461                 goto out;
 462         }
 463         rc = 0;
 464 out:
 465         /* Should be able to rely on deactivate_super called from
 466          * get_sb_nodev */
 467         return rc;
 468 }
 469
 470 /**
 471  * ecryptfs_read_super
 472  * @sb: The ecryptfs super block
 473  * @dev_name: The path to mount over
 474  *
 475  * Read the super block of the lower filesystem, and use
 476  * ecryptfs_interpose to create our initial inode and super block
 477  * struct.
 478  */
 479 static int ecryptfs_read_super(struct super_block *sb, const char *dev_name)
 480 {
 481         int rc;
 482         struct nameidata nd;
 483         struct dentry *lower_root;
 484         struct vfsmount *lower_mnt;
 485
 486         memset(&nd, 0, sizeof(struct nameidata));
 487         rc = path_lookup(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &nd);
 488         if (rc) {
 489                 ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n");
 490                 goto out;
 491         }
 492         lower_root = nd.dentry;
 493         lower_mnt = nd.mnt;
 494         ecryptfs_set_superblock_lower(sb, lower_root->d_sb);
 495         sb->s_maxbytes = lower_root->d_sb->s_maxbytes;
 496         ecryptfs_set_dentry_lower(sb->s_root, lower_root);
 497         ecryptfs_set_dentry_lower_mnt(sb->s_root, lower_mnt);
 498         if ((rc = ecryptfs_interpose(lower_root, sb->s_root, sb, 0)))
 499                 goto out_free;
 500         rc = 0;
 501         goto out;
 502 out_free:
 503         path_release(&nd);
 504 out:
 505         return rc;
 506 }
 507
 508 /**
 509  * ecryptfs_get_sb
 510  * @fs_type
 511  * @flags
 512  * @dev_name: The path to mount over
 513  * @raw_data: The options passed into the kernel
 514  *
 515  * The whole ecryptfs_get_sb process is broken into 4 functions:
 516  * ecryptfs_parse_options(): handle options passed to ecryptfs, if any
 517  * ecryptfs_fill_super(): used by get_sb_nodev, fills out the super_block
 518  *                        with as much information as it can before needing
 519  *                        the lower filesystem.
 520  * ecryptfs_read_super(): this accesses the lower filesystem and uses
 521  *                        ecryptfs_interpolate to perform most of the linking
 522  * ecryptfs_interpolate(): links the lower filesystem into ecryptfs
 523  */
 524 static int ecryptfs_get_sb(struct file_system_type *fs_type, int flags,
 525                         const char *dev_name, void *raw_data,
 526                         struct vfsmount *mnt)
 527 {
 528         int rc;
 529         struct super_block *sb;
 530
 531         rc = get_sb_nodev(fs_type, flags, raw_data, ecryptfs_fill_super, mnt);
 532         if (rc < 0) {
 533                 printk(KERN_ERR "Getting sb failed; rc = [%d]\n", rc);
 534                 goto out;
 535         }
 536         sb = mnt->mnt_sb;
 537         rc = ecryptfs_parse_options(sb, raw_data);
 538         if (rc) {
 539                 printk(KERN_ERR "Error parsing options; rc = [%d]\n", rc);
 540                 goto out_abort;
 541         }
 542         rc = ecryptfs_read_super(sb, dev_name);
 543         if (rc) {
 544                 printk(KERN_ERR "Reading sb failed; rc = [%d]\n", rc);
 545                 goto out_abort;
 546         }
 547         goto out;
 548 out_abort:
 549         dput(sb->s_root);
 550         up_write(&sb->s_umount);
 551         deactivate_super(sb);
 552 out:
 553         return rc;
 554 }
 555
 556 /**
 557  * ecryptfs_kill_block_super
 558  * @sb: The ecryptfs super block
 559  *
 560  * Used to bring the superblock down and free the private data.
 561  * Private data is free'd in ecryptfs_put_super()
 562  */
 563 static void ecryptfs_kill_block_super(struct super_block *sb)
 564 {
 565         generic_shutdown_super(sb);
 566 }
 567
 568 static struct file_system_type ecryptfs_fs_type = {
 569         .owner = THIS_MODULE,
 570         .name = "ecryptfs",
 571         .get_sb = ecryptfs_get_sb,
 572         .kill_sb = ecryptfs_kill_block_super,
 573         .fs_flags = 0
 574 };
 575
 576 /**
 577  * inode_info_init_once
 578  *
 579  * Initializes the ecryptfs_inode_info_cache when it is created
 580  */
 581 static void
 582 inode_info_init_once(void *vptr, struct kmem_cache *cachep, unsigned long flags)
 583 {
 584         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 585
 586         if (flags & SLAB_CTOR_CONSTRUCTOR)
 587                 inode_init_once(&ei->vfs_inode);
 588 }
 589
 590 static struct ecryptfs_cache_info {
 591         struct kmem_cache **cache;
 592         const char *name;
 593         size_t size;
 594         void (*ctor)(void*, struct kmem_cache *, unsigned long);
 595 } ecryptfs_cache_infos[] = {
 596         {
 597                 .cache = &ecryptfs_auth_tok_list_item_cache,
 598                 .name = "ecryptfs_auth_tok_list_item",
 599                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 600         },
 601         {
 602                 .cache = &ecryptfs_file_info_cache,
 603                 .name = "ecryptfs_file_cache",
 604                 .size = sizeof(struct ecryptfs_file_info),
 605         },
 606         {
 607                 .cache = &ecryptfs_dentry_info_cache,
 608                 .name = "ecryptfs_dentry_info_cache",
 609                 .size = sizeof(struct ecryptfs_dentry_info),
 610         },
 611         {
 612                 .cache = &ecryptfs_inode_info_cache,
 613                 .name = "ecryptfs_inode_cache",
 614                 .size = sizeof(struct ecryptfs_inode_info),
 615                 .ctor = inode_info_init_once,
 616         },
 617         {
 618                 .cache = &ecryptfs_sb_info_cache,
 619                 .name = "ecryptfs_sb_cache",
 620                 .size = sizeof(struct ecryptfs_sb_info),
 621         },
 622         {
 623                 .cache = &ecryptfs_header_cache_0,
 624                 .name = "ecryptfs_headers_0",
 625                 .size = PAGE_CACHE_SIZE,
 626         },
 627         {
 628                 .cache = &ecryptfs_header_cache_1,
 629                 .name = "ecryptfs_headers_1",
 630                 .size = PAGE_CACHE_SIZE,
 631         },
 632         {
 633                 .cache = &ecryptfs_header_cache_2,
 634                 .name = "ecryptfs_headers_2",
 635                 .size = PAGE_CACHE_SIZE,
 636         },
 637         {
 638                 .cache = &ecryptfs_xattr_cache,
 639                 .name = "ecryptfs_xattr_cache",
 640                 .size = PAGE_CACHE_SIZE,
 641         },
 642         {
 643                 .cache = &ecryptfs_lower_page_cache,
 644                 .name = "ecryptfs_lower_page_cache",
 645                 .size = PAGE_CACHE_SIZE,
 646         },
 647         {
 648                 .cache = &ecryptfs_key_record_cache,
 649                 .name = "ecryptfs_key_record_cache",
 650                 .size = sizeof(struct ecryptfs_key_record),
 651         },
 652 };
 653
 654 static void ecryptfs_free_kmem_caches(void)
 655 {
 656         int i;
 657
 658         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 659                 struct ecryptfs_cache_info *info;
 660
 661                 info = &ecryptfs_cache_infos[i];
 662                 if (*(info->cache))
 663                         kmem_cache_destroy(*(info->cache));
 664         }
 665 }
 666
 667 /**
 668  * ecryptfs_init_kmem_caches
 669  *
 670  * Returns zero on success; non-zero otherwise
 671  */
 672 static int ecryptfs_init_kmem_caches(void)
 673 {
 674         int i;
 675
 676         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 677                 struct ecryptfs_cache_info *info;
 678
 679                 info = &ecryptfs_cache_infos[i];
 680                 *(info->cache) = kmem_cache_create(info->name, info->size,
 681                                 0, SLAB_HWCACHE_ALIGN, info->ctor, NULL);
 682                 if (!*(info->cache)) {
 683                         ecryptfs_free_kmem_caches();
 684                         ecryptfs_printk(KERN_WARNING, "%s: "
 685                                         "kmem_cache_create failed\n",
 686                                         info->name);
 687                         return -ENOMEM;
 688                 }
 689         }
 690         return 0;
 691 }
 692
 693 struct ecryptfs_obj {
 694         char *name;
 695         struct list_head slot_list;
 696         struct kobject kobj;
 697 };
 698
 699 struct ecryptfs_attribute {
 700         struct attribute attr;
 701         ssize_t(*show) (struct ecryptfs_obj *, char *);
 702         ssize_t(*store) (struct ecryptfs_obj *, const char *, size_t);
 703 };
 704
 705 static ssize_t
 706 ecryptfs_attr_store(struct kobject *kobj,
 707                     struct attribute *attr, const char *buf, size_t len)
 708 {
 709         struct ecryptfs_obj *obj = container_of(kobj, struct ecryptfs_obj,
 710                                                 kobj);
 711         struct ecryptfs_attribute *attribute =
 712                 container_of(attr, struct ecryptfs_attribute, attr);
 713
 714         return (attribute->store ? attribute->store(obj, buf, len) : 0);
 715 }
 716
 717 static ssize_t
 718 ecryptfs_attr_show(struct kobject *kobj, struct attribute *attr, char *buf)
 719 {
 720         struct ecryptfs_obj *obj = container_of(kobj, struct ecryptfs_obj,
 721                                                 kobj);
 722         struct ecryptfs_attribute *attribute =
 723                 container_of(attr, struct ecryptfs_attribute, attr);
 724
 725         return (attribute->show ? attribute->show(obj, buf) : 0);
 726 }
 727
 728 static struct sysfs_ops ecryptfs_sysfs_ops = {
 729         .show = ecryptfs_attr_show,
 730         .store = ecryptfs_attr_store
 731 };
 732
 733 static struct kobj_type ecryptfs_ktype = {
 734         .sysfs_ops = &ecryptfs_sysfs_ops
 735 };
 736
 737 static decl_subsys(ecryptfs, &ecryptfs_ktype, NULL);
 738
 739 static ssize_t version_show(struct ecryptfs_obj *obj, char *buff)
 740 {
 741         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 742 }
 743
 744 static struct ecryptfs_attribute sysfs_attr_version = __ATTR_RO(version);
 745
 746 static struct ecryptfs_version_str_map_elem {
 747         u32 flag;
 748         char *str;
 749 } ecryptfs_version_str_map[] = {
 750         {ECRYPTFS_VERSIONING_PASSPHRASE, "passphrase"},
 751         {ECRYPTFS_VERSIONING_PUBKEY, "pubkey"},
 752         {ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH, "plaintext passthrough"},
 753         {ECRYPTFS_VERSIONING_POLICY, "policy"},
 754         {ECRYPTFS_VERSIONING_XATTR, "metadata in extended attribute"}
 755 };
 756
 757 static ssize_t version_str_show(struct ecryptfs_obj *obj, char *buff)
 758 {
 759         int i;
 760         int remaining = PAGE_SIZE;
 761         int total_written = 0;
 762
 763         buff[0] = '\0';
 764         for (i = 0; i < ARRAY_SIZE(ecryptfs_version_str_map); i++) {
 765                 int entry_size;
 766
 767                 if (!(ECRYPTFS_VERSIONING_MASK
 768                       & ecryptfs_version_str_map[i].flag))
 769                         continue;
 770                 entry_size = strlen(ecryptfs_version_str_map[i].str);
 771                 if ((entry_size + 2) > remaining)
 772                         goto out;
 773                 memcpy(buff, ecryptfs_version_str_map[i].str, entry_size);
 774                 buff[entry_size++] = '\n';
 775                 buff[entry_size] = '\0';
 776                 buff += entry_size;
 777                 total_written += entry_size;
 778                 remaining -= entry_size;
 779         }
 780 out:
 781         return total_written;
 782 }
 783
 784 static struct ecryptfs_attribute sysfs_attr_version_str = __ATTR_RO(version_str);
 785
 786 static int do_sysfs_registration(void)
 787 {
 788         int rc;
 789
 790         if ((rc = subsystem_register(&ecryptfs_subsys))) {
 791                 printk(KERN_ERR
 792                        "Unable to register ecryptfs sysfs subsystem\n");
 793                 goto out;
 794         }
 795         rc = sysfs_create_file(&ecryptfs_subsys.kobj,
 796                                &sysfs_attr_version.attr);
 797         if (rc) {
 798                 printk(KERN_ERR
 799                        "Unable to create ecryptfs version attribute\n");
 800                 subsystem_unregister(&ecryptfs_subsys);
 801                 goto out;
 802         }
 803         rc = sysfs_create_file(&ecryptfs_subsys.kobj,
 804                                &sysfs_attr_version_str.attr);
 805         if (rc) {
 806                 printk(KERN_ERR
 807                        "Unable to create ecryptfs version_str attribute\n");
 808                 sysfs_remove_file(&ecryptfs_subsys.kobj,
 809                                   &sysfs_attr_version.attr);
 810                 subsystem_unregister(&ecryptfs_subsys);
 811                 goto out;
 812         }
 813 out:
 814         return rc;
 815 }
 816
 817 static int __init ecryptfs_init(void)
 818 {
 819         int rc;
 820
 821         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
 822                 rc = -EINVAL;
 823                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 824                                 "larger than the host's page size, and so "
 825                                 "eCryptfs cannot run on this system. The "
 826                                 "default eCryptfs extent size is [%d] bytes; "
 827                                 "the page size is [%d] bytes.\n",
 828                                 ECRYPTFS_DEFAULT_EXTENT_SIZE, PAGE_CACHE_SIZE);
 829                 goto out;
 830         }
 831         rc = ecryptfs_init_kmem_caches();
 832         if (rc) {
 833                 printk(KERN_ERR
 834                        "Failed to allocate one or more kmem_cache objects\n");
 835                 goto out;
 836         }
 837         rc = register_filesystem(&ecryptfs_fs_type);
 838         if (rc) {
 839                 printk(KERN_ERR "Failed to register filesystem\n");
 840                 ecryptfs_free_kmem_caches();
 841                 goto out;
 842         }
 843         kobj_set_kset_s(&ecryptfs_subsys, fs_subsys);
 844         sysfs_attr_version.attr.owner = THIS_MODULE;
 845         sysfs_attr_version_str.attr.owner = THIS_MODULE;
 846         rc = do_sysfs_registration();
 847         if (rc) {
 848                 printk(KERN_ERR "sysfs registration failed\n");
 849                 unregister_filesystem(&ecryptfs_fs_type);
 850                 ecryptfs_free_kmem_caches();
 851                 goto out;
 852         }
 853         rc = ecryptfs_init_messaging(ecryptfs_transport);
 854         if (rc) {
 855                 ecryptfs_printk(KERN_ERR, "Failure occured while attempting to "
 856                                 "initialize the eCryptfs netlink socket\n");
 857         }
 858 out:
 859         return rc;
 860 }
 861
 862 static void __exit ecryptfs_exit(void)
 863 {
 864         sysfs_remove_file(&ecryptfs_subsys.kobj,
 865                           &sysfs_attr_version.attr);
 866         sysfs_remove_file(&ecryptfs_subsys.kobj,
 867                           &sysfs_attr_version_str.attr);
 868         subsystem_unregister(&ecryptfs_subsys);
 869         ecryptfs_release_messaging(ecryptfs_transport);
 870         unregister_filesystem(&ecryptfs_fs_type);
 871         ecryptfs_free_kmem_caches();
 872 }
 873
 874 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 875 MODULE_DESCRIPTION("eCryptfs");
 876
 877 MODULE_LICENSE("GPL");
 878
 879 module_init(ecryptfs_init)
 880 module_exit(ecryptfs_exit)