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_check_dev_ruid,
 179        ecryptfs_opt_err };
 180
 181 static const match_table_t tokens = {
 182         {ecryptfs_opt_sig, "sig=%s"},
 183         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 184         {ecryptfs_opt_cipher, "cipher=%s"},
 185         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
 186         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
 187         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
 188         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
 189         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
 190         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
 191         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
 192         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
 193         {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
 194         {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
 195         {ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
 196         {ecryptfs_opt_err, NULL}
 197 };
 198
 199 static int ecryptfs_init_global_auth_toks(
 200         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 201 {
 202         struct ecryptfs_global_auth_tok *global_auth_tok;
 203         struct ecryptfs_auth_tok *auth_tok;
 204         int rc = 0;
 205
 206         list_for_each_entry(global_auth_tok,
 207                             &mount_crypt_stat->global_auth_tok_list,
 208                             mount_crypt_stat_list) {
 209                 rc = ecryptfs_keyring_auth_tok_for_sig(
 210                         &global_auth_tok->global_auth_tok_key, &auth_tok,
 211                         global_auth_tok->sig);
 212                 if (rc) {
 213                         printk(KERN_ERR "Could not find valid key in user "
 214                                "session keyring for sig specified in mount "
 215                                "option: [%s]\n", global_auth_tok->sig);
 216                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 217                         goto out;
 218                 } else {
 219                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
 220                         up_write(&(global_auth_tok->global_auth_tok_key)->sem);
 221                 }
 222         }
 223 out:
 224         return rc;
 225 }
 226
 227 static void ecryptfs_init_mount_crypt_stat(
 228         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 229 {
 230         memset((void *)mount_crypt_stat, 0,
 231                sizeof(struct ecryptfs_mount_crypt_stat));
 232         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
 233         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
 234         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
 235 }
 236
 237 /**
 238  * ecryptfs_parse_options
 239  * @sb: The ecryptfs super block
 240  * @options: The options passed to the kernel
 241  * @check_ruid: set to 1 if device uid should be checked against the ruid
 242  *
 243  * Parse mount options:
 244  * debug=N         - ecryptfs_verbosity level for debug output
 245  * sig=XXX         - description(signature) of the key to use
 246  *
 247  * Returns the dentry object of the lower-level (lower/interposed)
 248  * directory; We want to mount our stackable file system on top of
 249  * that lower directory.
 250  *
 251  * The signature of the key to use must be the description of a key
 252  * already in the keyring. Mounting will fail if the key can not be
 253  * found.
 254  *
 255  * Returns zero on success; non-zero on error
 256  */
 257 static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
 258                                   uid_t *check_ruid)
 259 {
 260         char *p;
 261         int rc = 0;
 262         int sig_set = 0;
 263         int cipher_name_set = 0;
 264         int fn_cipher_name_set = 0;
 265         int cipher_key_bytes;
 266         int cipher_key_bytes_set = 0;
 267         int fn_cipher_key_bytes;
 268         int fn_cipher_key_bytes_set = 0;
 269         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 270                 &sbi->mount_crypt_stat;
 271         substring_t args[MAX_OPT_ARGS];
 272         int token;
 273         char *sig_src;
 274         char *cipher_name_dst;
 275         char *cipher_name_src;
 276         char *fn_cipher_name_dst;
 277         char *fn_cipher_name_src;
 278         char *fnek_dst;
 279         char *fnek_src;
 280         char *cipher_key_bytes_src;
 281         char *fn_cipher_key_bytes_src;
 282
 283         *check_ruid = 0;
 284
 285         if (!options) {
 286                 rc = -EINVAL;
 287                 goto out;
 288         }
 289         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
 290         while ((p = strsep(&options, ",")) != NULL) {
 291                 if (!*p)
 292                         continue;
 293                 token = match_token(p, tokens, args);
 294                 switch (token) {
 295                 case ecryptfs_opt_sig:
 296                 case ecryptfs_opt_ecryptfs_sig:
 297                         sig_src = args[0].from;
 298                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
 299                                                           sig_src, 0);
 300                         if (rc) {
 301                                 printk(KERN_ERR "Error attempting to register "
 302                                        "global sig; rc = [%d]\n", rc);
 303                                 goto out;
 304                         }
 305                         sig_set = 1;
 306                         break;
 307                 case ecryptfs_opt_cipher:
 308                 case ecryptfs_opt_ecryptfs_cipher:
 309                         cipher_name_src = args[0].from;
 310                         cipher_name_dst =
 311                                 mount_crypt_stat->
 312                                 global_default_cipher_name;
 313                         strncpy(cipher_name_dst, cipher_name_src,
 314                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 315                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 316                         cipher_name_set = 1;
 317                         break;
 318                 case ecryptfs_opt_ecryptfs_key_bytes:
 319                         cipher_key_bytes_src = args[0].from;
 320                         cipher_key_bytes =
 321                                 (int)simple_strtol(cipher_key_bytes_src,
 322                                                    &cipher_key_bytes_src, 0);
 323                         mount_crypt_stat->global_default_cipher_key_size =
 324                                 cipher_key_bytes;
 325                         cipher_key_bytes_set = 1;
 326                         break;
 327                 case ecryptfs_opt_passthrough:
 328                         mount_crypt_stat->flags |=
 329                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 330                         break;
 331                 case ecryptfs_opt_xattr_metadata:
 332                         mount_crypt_stat->flags |=
 333                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 334                         break;
 335                 case ecryptfs_opt_encrypted_view:
 336                         mount_crypt_stat->flags |=
 337                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 338                         mount_crypt_stat->flags |=
 339                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 340                         break;
 341                 case ecryptfs_opt_fnek_sig:
 342                         fnek_src = args[0].from;
 343                         fnek_dst =
 344                                 mount_crypt_stat->global_default_fnek_sig;
 345                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
 346                         mount_crypt_stat->global_default_fnek_sig[
 347                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
 348                         rc = ecryptfs_add_global_auth_tok(
 349                                 mount_crypt_stat,
 350                                 mount_crypt_stat->global_default_fnek_sig,
 351                                 ECRYPTFS_AUTH_TOK_FNEK);
 352                         if (rc) {
 353                                 printk(KERN_ERR "Error attempting to register "
 354                                        "global fnek sig [%s]; rc = [%d]\n",
 355                                        mount_crypt_stat->global_default_fnek_sig,
 356                                        rc);
 357                                 goto out;
 358                         }
 359                         mount_crypt_stat->flags |=
 360                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 361                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 362                         break;
 363                 case ecryptfs_opt_fn_cipher:
 364                         fn_cipher_name_src = args[0].from;
 365                         fn_cipher_name_dst =
 366                                 mount_crypt_stat->global_default_fn_cipher_name;
 367                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
 368                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 369                         mount_crypt_stat->global_default_fn_cipher_name[
 370                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 371                         fn_cipher_name_set = 1;
 372                         break;
 373                 case ecryptfs_opt_fn_cipher_key_bytes:
 374                         fn_cipher_key_bytes_src = args[0].from;
 375                         fn_cipher_key_bytes =
 376                                 (int)simple_strtol(fn_cipher_key_bytes_src,
 377                                                    &fn_cipher_key_bytes_src, 0);
 378                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
 379                                 fn_cipher_key_bytes;
 380                         fn_cipher_key_bytes_set = 1;
 381                         break;
 382                 case ecryptfs_opt_unlink_sigs:
 383                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
 384                         break;
 385                 case ecryptfs_opt_mount_auth_tok_only:
 386                         mount_crypt_stat->flags |=
 387                                 ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
 388                         break;
 389                 case ecryptfs_opt_check_dev_ruid:
 390                         *check_ruid = 1;
 391                         break;
 392                 case ecryptfs_opt_err:
 393                 default:
 394                         printk(KERN_WARNING
 395                                "%s: eCryptfs: unrecognized option [%s]\n",
 396                                __func__, p);
 397                 }
 398         }
 399         if (!sig_set) {
 400                 rc = -EINVAL;
 401                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
 402                                 "auth tok signature as a mount "
 403                                 "parameter; see the eCryptfs README\n");
 404                 goto out;
 405         }
 406         if (!cipher_name_set) {
 407                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 408
 409                 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 410                 strcpy(mount_crypt_stat->global_default_cipher_name,
 411                        ECRYPTFS_DEFAULT_CIPHER);
 412         }
 413         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 414             && !fn_cipher_name_set)
 415                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
 416                        mount_crypt_stat->global_default_cipher_name);
 417         if (!cipher_key_bytes_set)
 418                 mount_crypt_stat->global_default_cipher_key_size = 0;
 419         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 420             && !fn_cipher_key_bytes_set)
 421                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
 422                         mount_crypt_stat->global_default_cipher_key_size;
 423         mutex_lock(&key_tfm_list_mutex);
 424         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
 425                                  NULL)) {
 426                 rc = ecryptfs_add_new_key_tfm(
 427                         NULL, mount_crypt_stat->global_default_cipher_name,
 428                         mount_crypt_stat->global_default_cipher_key_size);
 429                 if (rc) {
 430                         printk(KERN_ERR "Error attempting to initialize "
 431                                "cipher with name = [%s] and key size = [%td]; "
 432                                "rc = [%d]\n",
 433                                mount_crypt_stat->global_default_cipher_name,
 434                                mount_crypt_stat->global_default_cipher_key_size,
 435                                rc);
 436                         rc = -EINVAL;
 437                         mutex_unlock(&key_tfm_list_mutex);
 438                         goto out;
 439                 }
 440         }
 441         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 442             && !ecryptfs_tfm_exists(
 443                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
 444                 rc = ecryptfs_add_new_key_tfm(
 445                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
 446                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
 447                 if (rc) {
 448                         printk(KERN_ERR "Error attempting to initialize "
 449                                "cipher with name = [%s] and key size = [%td]; "
 450                                "rc = [%d]\n",
 451                                mount_crypt_stat->global_default_fn_cipher_name,
 452                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
 453                                rc);
 454                         rc = -EINVAL;
 455                         mutex_unlock(&key_tfm_list_mutex);
 456                         goto out;
 457                 }
 458         }
 459         mutex_unlock(&key_tfm_list_mutex);
 460         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
 461         if (rc)
 462                 printk(KERN_WARNING "One or more global auth toks could not "
 463                        "properly register; rc = [%d]\n", rc);
 464 out:
 465         return rc;
 466 }
 467
 468 struct kmem_cache *ecryptfs_sb_info_cache;
 469 static struct file_system_type ecryptfs_fs_type;
 470
 471 /**
 472  * ecryptfs_get_sb
 473  * @fs_type
 474  * @flags
 475  * @dev_name: The path to mount over
 476  * @raw_data: The options passed into the kernel
 477  */
 478 static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
 479                         const char *dev_name, void *raw_data)
 480 {
 481         struct super_block *s;
 482         struct ecryptfs_sb_info *sbi;
 483         struct ecryptfs_dentry_info *root_info;
 484         const char *err = "Getting sb failed";
 485         struct inode *inode;
 486         struct path path;
 487         uid_t check_ruid;
 488         int rc;
 489
 490         sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
 491         if (!sbi) {
 492                 rc = -ENOMEM;
 493                 goto out;
 494         }
 495
 496         rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
 497         if (rc) {
 498                 err = "Error parsing options";
 499                 goto out;
 500         }
 501
 502         s = sget(fs_type, NULL, set_anon_super, flags, NULL);
 503         if (IS_ERR(s)) {
 504                 rc = PTR_ERR(s);
 505                 goto out;
 506         }
 507
 508         rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY);
 509         if (rc)
 510                 goto out1;
 511
 512         ecryptfs_set_superblock_private(s, sbi);
 513         s->s_bdi = &sbi->bdi;
 514
 515         /* ->kill_sb() will take care of sbi after that point */
 516         sbi = NULL;
 517         s->s_op = &ecryptfs_sops;
 518         s->s_d_op = &ecryptfs_dops;
 519
 520         err = "Reading sb failed";
 521         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 522         if (rc) {
 523                 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
 524                 goto out1;
 525         }
 526         if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
 527                 rc = -EINVAL;
 528                 printk(KERN_ERR "Mount on filesystem of type "
 529                         "eCryptfs explicitly disallowed due to "
 530                         "known incompatibilities\n");
 531                 goto out_free;
 532         }
 533
 534         if (check_ruid && path.dentry->d_inode->i_uid != current_uid()) {
 535                 rc = -EPERM;
 536                 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
 537                        "requested user (uid: %d)\n",
 538                        path.dentry->d_inode->i_uid, current_uid());
 539                 goto out_free;
 540         }
 541
 542         ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
 543         s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 544         s->s_blocksize = path.dentry->d_sb->s_blocksize;
 545         s->s_magic = ECRYPTFS_SUPER_MAGIC;
 546
 547         inode = ecryptfs_get_inode(path.dentry->d_inode, s);
 548         rc = PTR_ERR(inode);
 549         if (IS_ERR(inode))
 550                 goto out_free;
 551
 552         s->s_root = d_make_root(inode);
 553         if (!s->s_root) {
 554                 rc = -ENOMEM;
 555                 goto out_free;
 556         }
 557
 558         rc = -ENOMEM;
 559         root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 560         if (!root_info)
 561                 goto out_free;
 562
 563         /* ->kill_sb() will take care of root_info */
 564         ecryptfs_set_dentry_private(s->s_root, root_info);
 565         ecryptfs_set_dentry_lower(s->s_root, path.dentry);
 566         ecryptfs_set_dentry_lower_mnt(s->s_root, path.mnt);
 567
 568         s->s_flags |= MS_ACTIVE;
 569         return dget(s->s_root);
 570
 571 out_free:
 572         path_put(&path);
 573 out1:
 574         deactivate_locked_super(s);
 575 out:
 576         if (sbi) {
 577                 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
 578                 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
 579         }
 580         printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
 581         return ERR_PTR(rc);
 582 }
 583
 584 /**
 585  * ecryptfs_kill_block_super
 586  * @sb: The ecryptfs super block
 587  *
 588  * Used to bring the superblock down and free the private data.
 589  */
 590 static void ecryptfs_kill_block_super(struct super_block *sb)
 591 {
 592         struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
 593         kill_anon_super(sb);
 594         if (!sb_info)
 595                 return;
 596         ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
 597         bdi_destroy(&sb_info->bdi);
 598         kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
 599 }
 600
 601 static struct file_system_type ecryptfs_fs_type = {
 602         .owner = THIS_MODULE,
 603         .name = "ecryptfs",
 604         .mount = ecryptfs_mount,
 605         .kill_sb = ecryptfs_kill_block_super,
 606         .fs_flags = 0
 607 };
 608
 609 /**
 610  * inode_info_init_once
 611  *
 612  * Initializes the ecryptfs_inode_info_cache when it is created
 613  */
 614 static void
 615 inode_info_init_once(void *vptr)
 616 {
 617         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 618
 619         inode_init_once(&ei->vfs_inode);
 620 }
 621
 622 static struct ecryptfs_cache_info {
 623         struct kmem_cache **cache;
 624         const char *name;
 625         size_t size;
 626         void (*ctor)(void *obj);
 627 } ecryptfs_cache_infos[] = {
 628         {
 629                 .cache = &ecryptfs_auth_tok_list_item_cache,
 630                 .name = "ecryptfs_auth_tok_list_item",
 631                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 632         },
 633         {
 634                 .cache = &ecryptfs_file_info_cache,
 635                 .name = "ecryptfs_file_cache",
 636                 .size = sizeof(struct ecryptfs_file_info),
 637         },
 638         {
 639                 .cache = &ecryptfs_dentry_info_cache,
 640                 .name = "ecryptfs_dentry_info_cache",
 641                 .size = sizeof(struct ecryptfs_dentry_info),
 642         },
 643         {
 644                 .cache = &ecryptfs_inode_info_cache,
 645                 .name = "ecryptfs_inode_cache",
 646                 .size = sizeof(struct ecryptfs_inode_info),
 647                 .ctor = inode_info_init_once,
 648         },
 649         {
 650                 .cache = &ecryptfs_sb_info_cache,
 651                 .name = "ecryptfs_sb_cache",
 652                 .size = sizeof(struct ecryptfs_sb_info),
 653         },
 654         {
 655                 .cache = &ecryptfs_header_cache,
 656                 .name = "ecryptfs_headers",
 657                 .size = PAGE_CACHE_SIZE,
 658         },
 659         {
 660                 .cache = &ecryptfs_xattr_cache,
 661                 .name = "ecryptfs_xattr_cache",
 662                 .size = PAGE_CACHE_SIZE,
 663         },
 664         {
 665                 .cache = &ecryptfs_key_record_cache,
 666                 .name = "ecryptfs_key_record_cache",
 667                 .size = sizeof(struct ecryptfs_key_record),
 668         },
 669         {
 670                 .cache = &ecryptfs_key_sig_cache,
 671                 .name = "ecryptfs_key_sig_cache",
 672                 .size = sizeof(struct ecryptfs_key_sig),
 673         },
 674         {
 675                 .cache = &ecryptfs_global_auth_tok_cache,
 676                 .name = "ecryptfs_global_auth_tok_cache",
 677                 .size = sizeof(struct ecryptfs_global_auth_tok),
 678         },
 679         {
 680                 .cache = &ecryptfs_key_tfm_cache,
 681                 .name = "ecryptfs_key_tfm_cache",
 682                 .size = sizeof(struct ecryptfs_key_tfm),
 683         },
 684 };
 685
 686 static void ecryptfs_free_kmem_caches(void)
 687 {
 688         int i;
 689
 690         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 691                 struct ecryptfs_cache_info *info;
 692
 693                 info = &ecryptfs_cache_infos[i];
 694                 if (*(info->cache))
 695                         kmem_cache_destroy(*(info->cache));
 696         }
 697 }
 698
 699 /**
 700  * ecryptfs_init_kmem_caches
 701  *
 702  * Returns zero on success; non-zero otherwise
 703  */
 704 static int ecryptfs_init_kmem_caches(void)
 705 {
 706         int i;
 707
 708         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 709                 struct ecryptfs_cache_info *info;
 710
 711                 info = &ecryptfs_cache_infos[i];
 712                 *(info->cache) = kmem_cache_create(info->name, info->size,
 713                                 0, SLAB_HWCACHE_ALIGN, info->ctor);
 714                 if (!*(info->cache)) {
 715                         ecryptfs_free_kmem_caches();
 716                         ecryptfs_printk(KERN_WARNING, "%s: "
 717                                         "kmem_cache_create failed\n",
 718                                         info->name);
 719                         return -ENOMEM;
 720                 }
 721         }
 722         return 0;
 723 }
 724
 725 static struct kobject *ecryptfs_kobj;
 726
 727 static ssize_t version_show(struct kobject *kobj,
 728                             struct kobj_attribute *attr, char *buff)
 729 {
 730         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 731 }
 732
 733 static struct kobj_attribute version_attr = __ATTR_RO(version);
 734
 735 static struct attribute *attributes[] = {
 736         &version_attr.attr,
 737         NULL,
 738 };
 739
 740 static struct attribute_group attr_group = {
 741         .attrs = attributes,
 742 };
 743
 744 static int do_sysfs_registration(void)
 745 {
 746         int rc;
 747
 748         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 749         if (!ecryptfs_kobj) {
 750                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
 751                 rc = -ENOMEM;
 752                 goto out;
 753         }
 754         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 755         if (rc) {
 756                 printk(KERN_ERR
 757                        "Unable to create ecryptfs version attributes\n");
 758                 kobject_put(ecryptfs_kobj);
 759         }
 760 out:
 761         return rc;
 762 }
 763
 764 static void do_sysfs_unregistration(void)
 765 {
 766         sysfs_remove_group(ecryptfs_kobj, &attr_group);
 767         kobject_put(ecryptfs_kobj);
 768 }
 769
 770 static int __init ecryptfs_init(void)
 771 {
 772         int rc;
 773
 774         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
 775                 rc = -EINVAL;
 776                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 777                                 "larger than the host's page size, and so "
 778                                 "eCryptfs cannot run on this system. The "
 779                                 "default eCryptfs extent size is [%u] bytes; "
 780                                 "the page size is [%lu] bytes.\n",
 781                                 ECRYPTFS_DEFAULT_EXTENT_SIZE,
 782                                 (unsigned long)PAGE_CACHE_SIZE);
 783                 goto out;
 784         }
 785         rc = ecryptfs_init_kmem_caches();
 786         if (rc) {
 787                 printk(KERN_ERR
 788                        "Failed to allocate one or more kmem_cache objects\n");
 789                 goto out;
 790         }
 791         rc = do_sysfs_registration();
 792         if (rc) {
 793                 printk(KERN_ERR "sysfs registration failed\n");
 794                 goto out_free_kmem_caches;
 795         }
 796         rc = ecryptfs_init_kthread();
 797         if (rc) {
 798                 printk(KERN_ERR "%s: kthread initialization failed; "
 799                        "rc = [%d]\n", __func__, rc);
 800                 goto out_do_sysfs_unregistration;
 801         }
 802         rc = ecryptfs_init_messaging();
 803         if (rc) {
 804                 printk(KERN_ERR "Failure occurred while attempting to "
 805                                 "initialize the communications channel to "
 806                                 "ecryptfsd\n");
 807                 goto out_destroy_kthread;
 808         }
 809         rc = ecryptfs_init_crypto();
 810         if (rc) {
 811                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
 812                        "rc = [%d]\n", rc);
 813                 goto out_release_messaging;
 814         }
 815         rc = register_filesystem(&ecryptfs_fs_type);
 816         if (rc) {
 817                 printk(KERN_ERR "Failed to register filesystem\n");
 818                 goto out_destroy_crypto;
 819         }
 820         if (ecryptfs_verbosity > 0)
 821                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 822                         "will be written to the syslog!\n", ecryptfs_verbosity);
 823
 824         goto out;
 825 out_destroy_crypto:
 826         ecryptfs_destroy_crypto();
 827 out_release_messaging:
 828         ecryptfs_release_messaging();
 829 out_destroy_kthread:
 830         ecryptfs_destroy_kthread();
 831 out_do_sysfs_unregistration:
 832         do_sysfs_unregistration();
 833 out_free_kmem_caches:
 834         ecryptfs_free_kmem_caches();
 835 out:
 836         return rc;
 837 }
 838
 839 static void __exit ecryptfs_exit(void)
 840 {
 841         int rc;
 842
 843         rc = ecryptfs_destroy_crypto();
 844         if (rc)
 845                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 846                        "rc = [%d]\n", rc);
 847         ecryptfs_release_messaging();
 848         ecryptfs_destroy_kthread();
 849         do_sysfs_unregistration();
 850         unregister_filesystem(&ecryptfs_fs_type);
 851         ecryptfs_free_kmem_caches();
 852 }
 853
 854 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 855 MODULE_DESCRIPTION("eCryptfs");
 856
 857 MODULE_LICENSE("GPL");
 858
 859 module_init(ecryptfs_init)
 860 module_exit(ecryptfs_exit)