fs/ecryptfs/main.c

   1 /**
   2  * eCryptfs: Linux filesystem encryption layer
   3  *
   4  * Copyright (C) 1997-2003 Erez Zadok
   5  * Copyright (C) 2001-2003 Stony Brook University
   6  * Copyright (C) 2004-2007 International Business Machines Corp.
   7  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
   8  *              Michael C. Thompson <mcthomps@us.ibm.com>
   9  *              Tyler Hicks <tyhicks@ou.edu>
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License as
  13  * published by the Free Software Foundation; either version 2 of the
  14  * License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful, but
  17  * WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19  * General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  24  * 02111-1307, USA.
  25  */
  26
  27 #include <linux/dcache.h>
  28 #include <linux/file.h>
  29 #include <linux/module.h>
  30 #include <linux/namei.h>
  31 #include <linux/skbuff.h>
  32 #include <linux/crypto.h>
  33 #include <linux/mount.h>
  34 #include <linux/pagemap.h>
  35 #include <linux/key.h>
  36 #include <linux/parser.h>
  37 #include <linux/fs_stack.h>
  38 #include <linux/slab.h>
  39 #include <linux/magic.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 message buffer elements
  54  */
  55 unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
  56
  57 module_param(ecryptfs_message_buf_len, uint, 0);
  58 MODULE_PARM_DESC(ecryptfs_message_buf_len,
  59                  "Number of message buffer elements");
  60
  61 /**
  62  * Module parameter that defines the maximum guaranteed amount of time to wait
  63  * for a response from ecryptfsd.  The actual sleep time will be, more than
  64  * likely, a small amount greater than this specified value, but only less if
  65  * the message successfully arrives.
  66  */
  67 signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
  68
  69 module_param(ecryptfs_message_wait_timeout, long, 0);
  70 MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
  71                  "Maximum number of seconds that an operation will "
  72                  "sleep while waiting for a message response from "
  73                  "userspace");
  74
  75 /**
  76  * Module parameter that is an estimate of the maximum number of users
  77  * that will be concurrently using eCryptfs. Set this to the right
  78  * value to balance performance and memory use.
  79  */
  80 unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
  81
  82 module_param(ecryptfs_number_of_users, uint, 0);
  83 MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
  84                  "concurrent users of eCryptfs");
  85
  86 void __ecryptfs_printk(const char *fmt, ...)
  87 {
  88         va_list args;
  89         va_start(args, fmt);
  90         if (fmt[1] == '7') { /* KERN_DEBUG */
  91                 if (ecryptfs_verbosity >= 1)
  92                         vprintk(fmt, args);
  93         } else
  94                 vprintk(fmt, args);
  95         va_end(args);
  96 }
  97
  98 /**
  99  * ecryptfs_init_lower_file
 100  * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
 101  *                   the lower dentry and the lower mount set
 102  *
 103  * eCryptfs only ever keeps a single open file for every lower
 104  * inode. All I/O operations to the lower inode occur through that
 105  * file. When the first eCryptfs dentry that interposes with the first
 106  * lower dentry for that inode is created, this function creates the
 107  * lower file struct and associates it with the eCryptfs
 108  * inode. When all eCryptfs files associated with the inode are released, the
 109  * file is closed.
 110  *
 111  * The lower file will be opened with read/write permissions, if
 112  * possible. Otherwise, it is opened read-only.
 113  *
 114  * This function does nothing if a lower file is already
 115  * associated with the eCryptfs inode.
 116  *
 117  * Returns zero on success; non-zero otherwise
 118  */
 119 static int ecryptfs_init_lower_file(struct dentry *dentry,
 120                                     struct file **lower_file)
 121 {
 122         const struct cred *cred = current_cred();
 123         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 124         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 125         int rc;
 126
 127         rc = ecryptfs_privileged_open(lower_file, lower_dentry, lower_mnt,
 128                                       cred);
 129         if (rc) {
 130                 printk(KERN_ERR "Error opening lower file "
 131                        "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
 132                        "rc = [%d]\n", lower_dentry, lower_mnt, rc);
 133                 (*lower_file) = NULL;
 134         }
 135         return rc;
 136 }
 137
 138 int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
 139 {
 140         struct ecryptfs_inode_info *inode_info;
 141         int count, rc = 0;
 142
 143         inode_info = ecryptfs_inode_to_private(inode);
 144         mutex_lock(&inode_info->lower_file_mutex);
 145         count = atomic_inc_return(&inode_info->lower_file_count);
 146         if (WARN_ON_ONCE(count < 1))
 147                 rc = -EINVAL;
 148         else if (count == 1) {
 149                 rc = ecryptfs_init_lower_file(dentry,
 150                                               &inode_info->lower_file);
 151                 if (rc)
 152                         atomic_set(&inode_info->lower_file_count, 0);
 153         }
 154         mutex_unlock(&inode_info->lower_file_mutex);
 155         return rc;
 156 }
 157
 158 void ecryptfs_put_lower_file(struct inode *inode)
 159 {
 160         struct ecryptfs_inode_info *inode_info;
 161
 162         inode_info = ecryptfs_inode_to_private(inode);
 163         if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
 164                                       &inode_info->lower_file_mutex)) {
 165                 fput(inode_info->lower_file);
 166                 inode_info->lower_file = NULL;
 167                 mutex_unlock(&inode_info->lower_file_mutex);
 168         }
 169 }
 170
 171 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
 172        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
 173        ecryptfs_opt_ecryptfs_key_bytes,
 174        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
 175        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
 176        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
 177        ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
 178        ecryptfs_opt_err };
 179
 180 static const match_table_t tokens = {
 181         {ecryptfs_opt_sig, "sig=%s"},
 182         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 183         {ecryptfs_opt_cipher, "cipher=%s"},
 184         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
 185         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
 186         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
 187         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
 188         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
 189         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
 190         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
 191         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
 192         {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
 193         {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
 194         {ecryptfs_opt_err, NULL}
 195 };
 196
 197 static int ecryptfs_init_global_auth_toks(
 198         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 199 {
 200         struct ecryptfs_global_auth_tok *global_auth_tok;
 201         struct ecryptfs_auth_tok *auth_tok;
 202         int rc = 0;
 203
 204         list_for_each_entry(global_auth_tok,
 205                             &mount_crypt_stat->global_auth_tok_list,
 206                             mount_crypt_stat_list) {
 207                 rc = ecryptfs_keyring_auth_tok_for_sig(
 208                         &global_auth_tok->global_auth_tok_key, &auth_tok,
 209                         global_auth_tok->sig);
 210                 if (rc) {
 211                         printk(KERN_ERR "Could not find valid key in user "
 212                                "session keyring for sig specified in mount "
 213                                "option: [%s]\n", global_auth_tok->sig);
 214                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 215                         goto out;
 216                 } else {
 217                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
 218                         up_write(&(global_auth_tok->global_auth_tok_key)->sem);
 219                 }
 220         }
 221 out:
 222         return rc;
 223 }
 224
 225 static void ecryptfs_init_mount_crypt_stat(
 226         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 227 {
 228         memset((void *)mount_crypt_stat, 0,
 229                sizeof(struct ecryptfs_mount_crypt_stat));
 230         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
 231         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
 232         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
 233 }
 234
 235 /**
 236  * ecryptfs_parse_options
 237  * @sb: The ecryptfs super block
 238  * @options: The options passed to the kernel
 239  *
 240  * Parse mount options:
 241  * debug=N         - ecryptfs_verbosity level for debug output
 242  * sig=XXX         - description(signature) of the key to use
 243  *
 244  * Returns the dentry object of the lower-level (lower/interposed)
 245  * directory; We want to mount our stackable file system on top of
 246  * that lower directory.
 247  *
 248  * The signature of the key to use must be the description of a key
 249  * already in the keyring. Mounting will fail if the key can not be
 250  * found.
 251  *
 252  * Returns zero on success; non-zero on error
 253  */
 254 static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options)
 255 {
 256         char *p;
 257         int rc = 0;
 258         int sig_set = 0;
 259         int cipher_name_set = 0;
 260         int fn_cipher_name_set = 0;
 261         int cipher_key_bytes;
 262         int cipher_key_bytes_set = 0;
 263         int fn_cipher_key_bytes;
 264         int fn_cipher_key_bytes_set = 0;
 265         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 266                 &sbi->mount_crypt_stat;
 267         substring_t args[MAX_OPT_ARGS];
 268         int token;
 269         char *sig_src;
 270         char *cipher_name_dst;
 271         char *cipher_name_src;
 272         char *fn_cipher_name_dst;
 273         char *fn_cipher_name_src;
 274         char *fnek_dst;
 275         char *fnek_src;
 276         char *cipher_key_bytes_src;
 277         char *fn_cipher_key_bytes_src;
 278
 279         if (!options) {
 280                 rc = -EINVAL;
 281                 goto out;
 282         }
 283         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
 284         while ((p = strsep(&options, ",")) != NULL) {
 285                 if (!*p)
 286                         continue;
 287                 token = match_token(p, tokens, args);
 288                 switch (token) {
 289                 case ecryptfs_opt_sig:
 290                 case ecryptfs_opt_ecryptfs_sig:
 291                         sig_src = args[0].from;
 292                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
 293                                                           sig_src, 0);
 294                         if (rc) {
 295                                 printk(KERN_ERR "Error attempting to register "
 296                                        "global sig; rc = [%d]\n", rc);
 297                                 goto out;
 298                         }
 299                         sig_set = 1;
 300                         break;
 301                 case ecryptfs_opt_cipher:
 302                 case ecryptfs_opt_ecryptfs_cipher:
 303                         cipher_name_src = args[0].from;
 304                         cipher_name_dst =
 305                                 mount_crypt_stat->
 306                                 global_default_cipher_name;
 307                         strncpy(cipher_name_dst, cipher_name_src,
 308                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 309                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 310                         cipher_name_set = 1;
 311                         break;
 312                 case ecryptfs_opt_ecryptfs_key_bytes:
 313                         cipher_key_bytes_src = args[0].from;
 314                         cipher_key_bytes =
 315                                 (int)simple_strtol(cipher_key_bytes_src,
 316                                                    &cipher_key_bytes_src, 0);
 317                         mount_crypt_stat->global_default_cipher_key_size =
 318                                 cipher_key_bytes;
 319                         cipher_key_bytes_set = 1;
 320                         break;
 321                 case ecryptfs_opt_passthrough:
 322                         mount_crypt_stat->flags |=
 323                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 324                         break;
 325                 case ecryptfs_opt_xattr_metadata:
 326                         mount_crypt_stat->flags |=
 327                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 328                         break;
 329                 case ecryptfs_opt_encrypted_view:
 330                         mount_crypt_stat->flags |=
 331                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 332                         mount_crypt_stat->flags |=
 333                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 334                         break;
 335                 case ecryptfs_opt_fnek_sig:
 336                         fnek_src = args[0].from;
 337                         fnek_dst =
 338                                 mount_crypt_stat->global_default_fnek_sig;
 339                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
 340                         mount_crypt_stat->global_default_fnek_sig[
 341                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
 342                         rc = ecryptfs_add_global_auth_tok(
 343                                 mount_crypt_stat,
 344                                 mount_crypt_stat->global_default_fnek_sig,
 345                                 ECRYPTFS_AUTH_TOK_FNEK);
 346                         if (rc) {
 347                                 printk(KERN_ERR "Error attempting to register "
 348                                        "global fnek sig [%s]; rc = [%d]\n",
 349                                        mount_crypt_stat->global_default_fnek_sig,
 350                                        rc);
 351                                 goto out;
 352                         }
 353                         mount_crypt_stat->flags |=
 354                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 355                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 356                         break;
 357                 case ecryptfs_opt_fn_cipher:
 358                         fn_cipher_name_src = args[0].from;
 359                         fn_cipher_name_dst =
 360                                 mount_crypt_stat->global_default_fn_cipher_name;
 361                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
 362                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 363                         mount_crypt_stat->global_default_fn_cipher_name[
 364                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 365                         fn_cipher_name_set = 1;
 366                         break;
 367                 case ecryptfs_opt_fn_cipher_key_bytes:
 368                         fn_cipher_key_bytes_src = args[0].from;
 369                         fn_cipher_key_bytes =
 370                                 (int)simple_strtol(fn_cipher_key_bytes_src,
 371                                                    &fn_cipher_key_bytes_src, 0);
 372                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
 373                                 fn_cipher_key_bytes;
 374                         fn_cipher_key_bytes_set = 1;
 375                         break;
 376                 case ecryptfs_opt_unlink_sigs:
 377                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
 378                         break;
 379                 case ecryptfs_opt_mount_auth_tok_only:
 380                         mount_crypt_stat->flags |=
 381                                 ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
 382                         break;
 383                 case ecryptfs_opt_err:
 384                 default:
 385                         printk(KERN_WARNING
 386                                "%s: eCryptfs: unrecognized option [%s]\n",
 387                                __func__, p);
 388                 }
 389         }
 390         if (!sig_set) {
 391                 rc = -EINVAL;
 392                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
 393                                 "auth tok signature as a mount "
 394                                 "parameter; see the eCryptfs README\n");
 395                 goto out;
 396         }
 397         if (!cipher_name_set) {
 398                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 399
 400                 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 401                 strcpy(mount_crypt_stat->global_default_cipher_name,
 402                        ECRYPTFS_DEFAULT_CIPHER);
 403         }
 404         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 405             && !fn_cipher_name_set)
 406                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
 407                        mount_crypt_stat->global_default_cipher_name);
 408         if (!cipher_key_bytes_set)
 409                 mount_crypt_stat->global_default_cipher_key_size = 0;
 410         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 411             && !fn_cipher_key_bytes_set)
 412                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
 413                         mount_crypt_stat->global_default_cipher_key_size;
 414         mutex_lock(&key_tfm_list_mutex);
 415         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
 416                                  NULL)) {
 417                 rc = ecryptfs_add_new_key_tfm(
 418                         NULL, mount_crypt_stat->global_default_cipher_name,
 419                         mount_crypt_stat->global_default_cipher_key_size);
 420                 if (rc) {
 421                         printk(KERN_ERR "Error attempting to initialize "
 422                                "cipher with name = [%s] and key size = [%td]; "
 423                                "rc = [%d]\n",
 424                                mount_crypt_stat->global_default_cipher_name,
 425                                mount_crypt_stat->global_default_cipher_key_size,
 426                                rc);
 427                         rc = -EINVAL;
 428                         mutex_unlock(&key_tfm_list_mutex);
 429                         goto out;
 430                 }
 431         }
 432         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 433             && !ecryptfs_tfm_exists(
 434                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
 435                 rc = ecryptfs_add_new_key_tfm(
 436                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
 437                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
 438                 if (rc) {
 439                         printk(KERN_ERR "Error attempting to initialize "
 440                                "cipher with name = [%s] and key size = [%td]; "
 441                                "rc = [%d]\n",
 442                                mount_crypt_stat->global_default_fn_cipher_name,
 443                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
 444                                rc);
 445                         rc = -EINVAL;
 446                         mutex_unlock(&key_tfm_list_mutex);
 447                         goto out;
 448                 }
 449         }
 450         mutex_unlock(&key_tfm_list_mutex);
 451         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
 452         if (rc)
 453                 printk(KERN_WARNING "One or more global auth toks could not "
 454                        "properly register; rc = [%d]\n", rc);
 455 out:
 456         return rc;
 457 }
 458
 459 struct kmem_cache *ecryptfs_sb_info_cache;
 460 static struct file_system_type ecryptfs_fs_type;
 461
 462 /**
 463  * ecryptfs_get_sb
 464  * @fs_type
 465  * @flags
 466  * @dev_name: The path to mount over
 467  * @raw_data: The options passed into the kernel
 468  */
 469 static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
 470                         const char *dev_name, void *raw_data)
 471 {
 472         struct super_block *s;
 473         struct ecryptfs_sb_info *sbi;
 474         struct ecryptfs_dentry_info *root_info;
 475         const char *err = "Getting sb failed";
 476         struct inode *inode;
 477         struct path path;
 478         int rc;
 479
 480         sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
 481         if (!sbi) {
 482                 rc = -ENOMEM;
 483                 goto out;
 484         }
 485
 486         rc = ecryptfs_parse_options(sbi, raw_data);
 487         if (rc) {
 488                 err = "Error parsing options";
 489                 goto out;
 490         }
 491
 492         s = sget(fs_type, NULL, set_anon_super, NULL);
 493         if (IS_ERR(s)) {
 494                 rc = PTR_ERR(s);
 495                 goto out;
 496         }
 497
 498         s->s_flags = flags;
 499         rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY);
 500         if (rc)
 501                 goto out1;
 502
 503         ecryptfs_set_superblock_private(s, sbi);
 504         s->s_bdi = &sbi->bdi;
 505
 506         /* ->kill_sb() will take care of sbi after that point */
 507         sbi = NULL;
 508         s->s_op = &ecryptfs_sops;
 509         s->s_d_op = &ecryptfs_dops;
 510
 511         err = "Reading sb failed";
 512         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 513         if (rc) {
 514                 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
 515                 goto out1;
 516         }
 517         if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
 518                 rc = -EINVAL;
 519                 printk(KERN_ERR "Mount on filesystem of type "
 520                         "eCryptfs explicitly disallowed due to "
 521                         "known incompatibilities\n");
 522                 goto out_free;
 523         }
 524         ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
 525         s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 526         s->s_blocksize = path.dentry->d_sb->s_blocksize;
 527         s->s_magic = ECRYPTFS_SUPER_MAGIC;
 528
 529         inode = ecryptfs_get_inode(path.dentry->d_inode, s);
 530         rc = PTR_ERR(inode);
 531         if (IS_ERR(inode))
 532                 goto out_free;
 533
 534         s->s_root = d_alloc_root(inode);
 535         if (!s->s_root) {
 536                 iput(inode);
 537                 rc = -ENOMEM;
 538                 goto out_free;
 539         }
 540
 541         rc = -ENOMEM;
 542         root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 543         if (!root_info)
 544                 goto out_free;
 545
 546         /* ->kill_sb() will take care of root_info */
 547         ecryptfs_set_dentry_private(s->s_root, root_info);
 548         ecryptfs_set_dentry_lower(s->s_root, path.dentry);
 549         ecryptfs_set_dentry_lower_mnt(s->s_root, path.mnt);
 550
 551         s->s_flags |= MS_ACTIVE;
 552         return dget(s->s_root);
 553
 554 out_free:
 555         path_put(&path);
 556 out1:
 557         deactivate_locked_super(s);
 558 out:
 559         if (sbi) {
 560                 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
 561                 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
 562         }
 563         printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
 564         return ERR_PTR(rc);
 565 }
 566
 567 /**
 568  * ecryptfs_kill_block_super
 569  * @sb: The ecryptfs super block
 570  *
 571  * Used to bring the superblock down and free the private data.
 572  */
 573 static void ecryptfs_kill_block_super(struct super_block *sb)
 574 {
 575         struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
 576         kill_anon_super(sb);
 577         if (!sb_info)
 578                 return;
 579         ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
 580         bdi_destroy(&sb_info->bdi);
 581         kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
 582 }
 583
 584 static struct file_system_type ecryptfs_fs_type = {
 585         .owner = THIS_MODULE,
 586         .name = "ecryptfs",
 587         .mount = ecryptfs_mount,
 588         .kill_sb = ecryptfs_kill_block_super,
 589         .fs_flags = 0
 590 };
 591
 592 /**
 593  * inode_info_init_once
 594  *
 595  * Initializes the ecryptfs_inode_info_cache when it is created
 596  */
 597 static void
 598 inode_info_init_once(void *vptr)
 599 {
 600         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 601
 602         inode_init_once(&ei->vfs_inode);
 603 }
 604
 605 static struct ecryptfs_cache_info {
 606         struct kmem_cache **cache;
 607         const char *name;
 608         size_t size;
 609         void (*ctor)(void *obj);
 610 } ecryptfs_cache_infos[] = {
 611         {
 612                 .cache = &ecryptfs_auth_tok_list_item_cache,
 613                 .name = "ecryptfs_auth_tok_list_item",
 614                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 615         },
 616         {
 617                 .cache = &ecryptfs_file_info_cache,
 618                 .name = "ecryptfs_file_cache",
 619                 .size = sizeof(struct ecryptfs_file_info),
 620         },
 621         {
 622                 .cache = &ecryptfs_dentry_info_cache,
 623                 .name = "ecryptfs_dentry_info_cache",
 624                 .size = sizeof(struct ecryptfs_dentry_info),
 625         },
 626         {
 627                 .cache = &ecryptfs_inode_info_cache,
 628                 .name = "ecryptfs_inode_cache",
 629                 .size = sizeof(struct ecryptfs_inode_info),
 630                 .ctor = inode_info_init_once,
 631         },
 632         {
 633                 .cache = &ecryptfs_sb_info_cache,
 634                 .name = "ecryptfs_sb_cache",
 635                 .size = sizeof(struct ecryptfs_sb_info),
 636         },
 637         {
 638                 .cache = &ecryptfs_header_cache,
 639                 .name = "ecryptfs_headers",
 640                 .size = PAGE_CACHE_SIZE,
 641         },
 642         {
 643                 .cache = &ecryptfs_xattr_cache,
 644                 .name = "ecryptfs_xattr_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                 .cache = &ecryptfs_key_sig_cache,
 654                 .name = "ecryptfs_key_sig_cache",
 655                 .size = sizeof(struct ecryptfs_key_sig),
 656         },
 657         {
 658                 .cache = &ecryptfs_global_auth_tok_cache,
 659                 .name = "ecryptfs_global_auth_tok_cache",
 660                 .size = sizeof(struct ecryptfs_global_auth_tok),
 661         },
 662         {
 663                 .cache = &ecryptfs_key_tfm_cache,
 664                 .name = "ecryptfs_key_tfm_cache",
 665                 .size = sizeof(struct ecryptfs_key_tfm),
 666         },
 667         {
 668                 .cache = &ecryptfs_open_req_cache,
 669                 .name = "ecryptfs_open_req_cache",
 670                 .size = sizeof(struct ecryptfs_open_req),
 671         },
 672 };
 673
 674 static void ecryptfs_free_kmem_caches(void)
 675 {
 676         int i;
 677
 678         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 679                 struct ecryptfs_cache_info *info;
 680
 681                 info = &ecryptfs_cache_infos[i];
 682                 if (*(info->cache))
 683                         kmem_cache_destroy(*(info->cache));
 684         }
 685 }
 686
 687 /**
 688  * ecryptfs_init_kmem_caches
 689  *
 690  * Returns zero on success; non-zero otherwise
 691  */
 692 static int ecryptfs_init_kmem_caches(void)
 693 {
 694         int i;
 695
 696         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 697                 struct ecryptfs_cache_info *info;
 698
 699                 info = &ecryptfs_cache_infos[i];
 700                 *(info->cache) = kmem_cache_create(info->name, info->size,
 701                                 0, SLAB_HWCACHE_ALIGN, info->ctor);
 702                 if (!*(info->cache)) {
 703                         ecryptfs_free_kmem_caches();
 704                         ecryptfs_printk(KERN_WARNING, "%s: "
 705                                         "kmem_cache_create failed\n",
 706                                         info->name);
 707                         return -ENOMEM;
 708                 }
 709         }
 710         return 0;
 711 }
 712
 713 static struct kobject *ecryptfs_kobj;
 714
 715 static ssize_t version_show(struct kobject *kobj,
 716                             struct kobj_attribute *attr, char *buff)
 717 {
 718         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 719 }
 720
 721 static struct kobj_attribute version_attr = __ATTR_RO(version);
 722
 723 static struct attribute *attributes[] = {
 724         &version_attr.attr,
 725         NULL,
 726 };
 727
 728 static struct attribute_group attr_group = {
 729         .attrs = attributes,
 730 };
 731
 732 static int do_sysfs_registration(void)
 733 {
 734         int rc;
 735
 736         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 737         if (!ecryptfs_kobj) {
 738                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
 739                 rc = -ENOMEM;
 740                 goto out;
 741         }
 742         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 743         if (rc) {
 744                 printk(KERN_ERR
 745                        "Unable to create ecryptfs version attributes\n");
 746                 kobject_put(ecryptfs_kobj);
 747         }
 748 out:
 749         return rc;
 750 }
 751
 752 static void do_sysfs_unregistration(void)
 753 {
 754         sysfs_remove_group(ecryptfs_kobj, &attr_group);
 755         kobject_put(ecryptfs_kobj);
 756 }
 757
 758 static int __init ecryptfs_init(void)
 759 {
 760         int rc;
 761
 762         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
 763                 rc = -EINVAL;
 764                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 765                                 "larger than the host's page size, and so "
 766                                 "eCryptfs cannot run on this system. The "
 767                                 "default eCryptfs extent size is [%u] bytes; "
 768                                 "the page size is [%lu] bytes.\n",
 769                                 ECRYPTFS_DEFAULT_EXTENT_SIZE,
 770                                 (unsigned long)PAGE_CACHE_SIZE);
 771                 goto out;
 772         }
 773         rc = ecryptfs_init_kmem_caches();
 774         if (rc) {
 775                 printk(KERN_ERR
 776                        "Failed to allocate one or more kmem_cache objects\n");
 777                 goto out;
 778         }
 779         rc = register_filesystem(&ecryptfs_fs_type);
 780         if (rc) {
 781                 printk(KERN_ERR "Failed to register filesystem\n");
 782                 goto out_free_kmem_caches;
 783         }
 784         rc = do_sysfs_registration();
 785         if (rc) {
 786                 printk(KERN_ERR "sysfs registration failed\n");
 787                 goto out_unregister_filesystem;
 788         }
 789         rc = ecryptfs_init_kthread();
 790         if (rc) {
 791                 printk(KERN_ERR "%s: kthread initialization failed; "
 792                        "rc = [%d]\n", __func__, rc);
 793                 goto out_do_sysfs_unregistration;
 794         }
 795         rc = ecryptfs_init_messaging();
 796         if (rc) {
 797                 printk(KERN_ERR "Failure occurred while attempting to "
 798                                 "initialize the communications channel to "
 799                                 "ecryptfsd\n");
 800                 goto out_destroy_kthread;
 801         }
 802         rc = ecryptfs_init_crypto();
 803         if (rc) {
 804                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
 805                        "rc = [%d]\n", rc);
 806                 goto out_release_messaging;
 807         }
 808         if (ecryptfs_verbosity > 0)
 809                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 810                         "will be written to the syslog!\n", ecryptfs_verbosity);
 811
 812         goto out;
 813 out_release_messaging:
 814         ecryptfs_release_messaging();
 815 out_destroy_kthread:
 816         ecryptfs_destroy_kthread();
 817 out_do_sysfs_unregistration:
 818         do_sysfs_unregistration();
 819 out_unregister_filesystem:
 820         unregister_filesystem(&ecryptfs_fs_type);
 821 out_free_kmem_caches:
 822         ecryptfs_free_kmem_caches();
 823 out:
 824         return rc;
 825 }
 826
 827 static void __exit ecryptfs_exit(void)
 828 {
 829         int rc;
 830
 831         rc = ecryptfs_destroy_crypto();
 832         if (rc)
 833                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 834                        "rc = [%d]\n", rc);
 835         ecryptfs_release_messaging();
 836         ecryptfs_destroy_kthread();
 837         do_sysfs_unregistration();
 838         unregister_filesystem(&ecryptfs_fs_type);
 839         ecryptfs_free_kmem_caches();
 840 }
 841
 842 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 843 MODULE_DESCRIPTION("eCryptfs");
 844
 845 MODULE_LICENSE("GPL");
 846
 847 module_init(ecryptfs_init)
 848 module_exit(ecryptfs_exit)