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                 filemap_write_and_wait(inode->i_mapping);
 166                 fput(inode_info->lower_file);
 167                 inode_info->lower_file = NULL;
 168                 mutex_unlock(&inode_info->lower_file_mutex);
 169         }
 170 }
 171
 172 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
 173        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
 174        ecryptfs_opt_ecryptfs_key_bytes,
 175        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
 176        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
 177        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
 178        ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
 179        ecryptfs_opt_check_dev_ruid,
 180        ecryptfs_opt_err };
 181
 182 static const match_table_t tokens = {
 183         {ecryptfs_opt_sig, "sig=%s"},
 184         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 185         {ecryptfs_opt_cipher, "cipher=%s"},
 186         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
 187         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
 188         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
 189         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
 190         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
 191         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
 192         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
 193         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
 194         {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
 195         {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
 196         {ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
 197         {ecryptfs_opt_err, NULL}
 198 };
 199
 200 static int ecryptfs_init_global_auth_toks(
 201         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 202 {
 203         struct ecryptfs_global_auth_tok *global_auth_tok;
 204         struct ecryptfs_auth_tok *auth_tok;
 205         int rc = 0;
 206
 207         list_for_each_entry(global_auth_tok,
 208                             &mount_crypt_stat->global_auth_tok_list,
 209                             mount_crypt_stat_list) {
 210                 rc = ecryptfs_keyring_auth_tok_for_sig(
 211                         &global_auth_tok->global_auth_tok_key, &auth_tok,
 212                         global_auth_tok->sig);
 213                 if (rc) {
 214                         printk(KERN_ERR "Could not find valid key in user "
 215                                "session keyring for sig specified in mount "
 216                                "option: [%s]\n", global_auth_tok->sig);
 217                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 218                         goto out;
 219                 } else {
 220                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
 221                         up_write(&(global_auth_tok->global_auth_tok_key)->sem);
 222                 }
 223         }
 224 out:
 225         return rc;
 226 }
 227
 228 static void ecryptfs_init_mount_crypt_stat(
 229         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 230 {
 231         memset((void *)mount_crypt_stat, 0,
 232                sizeof(struct ecryptfs_mount_crypt_stat));
 233         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
 234         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
 235         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
 236 }
 237
 238 /**
 239  * ecryptfs_parse_options
 240  * @sb: The ecryptfs super block
 241  * @options: The options passed to the kernel
 242  * @check_ruid: set to 1 if device uid should be checked against the ruid
 243  *
 244  * Parse mount options:
 245  * debug=N         - ecryptfs_verbosity level for debug output
 246  * sig=XXX         - description(signature) of the key to use
 247  *
 248  * Returns the dentry object of the lower-level (lower/interposed)
 249  * directory; We want to mount our stackable file system on top of
 250  * that lower directory.
 251  *
 252  * The signature of the key to use must be the description of a key
 253  * already in the keyring. Mounting will fail if the key can not be
 254  * found.
 255  *
 256  * Returns zero on success; non-zero on error
 257  */
 258 static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
 259                                   uid_t *check_ruid)
 260 {
 261         char *p;
 262         int rc = 0;
 263         int sig_set = 0;
 264         int cipher_name_set = 0;
 265         int fn_cipher_name_set = 0;
 266         int cipher_key_bytes;
 267         int cipher_key_bytes_set = 0;
 268         int fn_cipher_key_bytes;
 269         int fn_cipher_key_bytes_set = 0;
 270         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 271                 &sbi->mount_crypt_stat;
 272         substring_t args[MAX_OPT_ARGS];
 273         int token;
 274         char *sig_src;
 275         char *cipher_name_dst;
 276         char *cipher_name_src;
 277         char *fn_cipher_name_dst;
 278         char *fn_cipher_name_src;
 279         char *fnek_dst;
 280         char *fnek_src;
 281         char *cipher_key_bytes_src;
 282         char *fn_cipher_key_bytes_src;
 283         u8 cipher_code;
 284
 285         *check_ruid = 0;
 286
 287         if (!options) {
 288                 rc = -EINVAL;
 289                 goto out;
 290         }
 291         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
 292         while ((p = strsep(&options, ",")) != NULL) {
 293                 if (!*p)
 294                         continue;
 295                 token = match_token(p, tokens, args);
 296                 switch (token) {
 297                 case ecryptfs_opt_sig:
 298                 case ecryptfs_opt_ecryptfs_sig:
 299                         sig_src = args[0].from;
 300                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
 301                                                           sig_src, 0);
 302                         if (rc) {
 303                                 printk(KERN_ERR "Error attempting to register "
 304                                        "global sig; rc = [%d]\n", rc);
 305                                 goto out;
 306                         }
 307                         sig_set = 1;
 308                         break;
 309                 case ecryptfs_opt_cipher:
 310                 case ecryptfs_opt_ecryptfs_cipher:
 311                         cipher_name_src = args[0].from;
 312                         cipher_name_dst =
 313                                 mount_crypt_stat->
 314                                 global_default_cipher_name;
 315                         strncpy(cipher_name_dst, cipher_name_src,
 316                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 317                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 318                         cipher_name_set = 1;
 319                         break;
 320                 case ecryptfs_opt_ecryptfs_key_bytes:
 321                         cipher_key_bytes_src = args[0].from;
 322                         cipher_key_bytes =
 323                                 (int)simple_strtol(cipher_key_bytes_src,
 324                                                    &cipher_key_bytes_src, 0);
 325                         mount_crypt_stat->global_default_cipher_key_size =
 326                                 cipher_key_bytes;
 327                         cipher_key_bytes_set = 1;
 328                         break;
 329                 case ecryptfs_opt_passthrough:
 330                         mount_crypt_stat->flags |=
 331                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 332                         break;
 333                 case ecryptfs_opt_xattr_metadata:
 334                         mount_crypt_stat->flags |=
 335                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 336                         break;
 337                 case ecryptfs_opt_encrypted_view:
 338                         mount_crypt_stat->flags |=
 339                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 340                         mount_crypt_stat->flags |=
 341                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 342                         break;
 343                 case ecryptfs_opt_fnek_sig:
 344                         fnek_src = args[0].from;
 345                         fnek_dst =
 346                                 mount_crypt_stat->global_default_fnek_sig;
 347                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
 348                         mount_crypt_stat->global_default_fnek_sig[
 349                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
 350                         rc = ecryptfs_add_global_auth_tok(
 351                                 mount_crypt_stat,
 352                                 mount_crypt_stat->global_default_fnek_sig,
 353                                 ECRYPTFS_AUTH_TOK_FNEK);
 354                         if (rc) {
 355                                 printk(KERN_ERR "Error attempting to register "
 356                                        "global fnek sig [%s]; rc = [%d]\n",
 357                                        mount_crypt_stat->global_default_fnek_sig,
 358                                        rc);
 359                                 goto out;
 360                         }
 361                         mount_crypt_stat->flags |=
 362                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 363                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 364                         break;
 365                 case ecryptfs_opt_fn_cipher:
 366                         fn_cipher_name_src = args[0].from;
 367                         fn_cipher_name_dst =
 368                                 mount_crypt_stat->global_default_fn_cipher_name;
 369                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
 370                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 371                         mount_crypt_stat->global_default_fn_cipher_name[
 372                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 373                         fn_cipher_name_set = 1;
 374                         break;
 375                 case ecryptfs_opt_fn_cipher_key_bytes:
 376                         fn_cipher_key_bytes_src = args[0].from;
 377                         fn_cipher_key_bytes =
 378                                 (int)simple_strtol(fn_cipher_key_bytes_src,
 379                                                    &fn_cipher_key_bytes_src, 0);
 380                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
 381                                 fn_cipher_key_bytes;
 382                         fn_cipher_key_bytes_set = 1;
 383                         break;
 384                 case ecryptfs_opt_unlink_sigs:
 385                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
 386                         break;
 387                 case ecryptfs_opt_mount_auth_tok_only:
 388                         mount_crypt_stat->flags |=
 389                                 ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
 390                         break;
 391                 case ecryptfs_opt_check_dev_ruid:
 392                         *check_ruid = 1;
 393                         break;
 394                 case ecryptfs_opt_err:
 395                 default:
 396                         printk(KERN_WARNING
 397                                "%s: eCryptfs: unrecognized option [%s]\n",
 398                                __func__, p);
 399                 }
 400         }
 401         if (!sig_set) {
 402                 rc = -EINVAL;
 403                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
 404                                 "auth tok signature as a mount "
 405                                 "parameter; see the eCryptfs README\n");
 406                 goto out;
 407         }
 408         if (!cipher_name_set) {
 409                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 410
 411                 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 412                 strcpy(mount_crypt_stat->global_default_cipher_name,
 413                        ECRYPTFS_DEFAULT_CIPHER);
 414         }
 415         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 416             && !fn_cipher_name_set)
 417                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
 418                        mount_crypt_stat->global_default_cipher_name);
 419         if (!cipher_key_bytes_set)
 420                 mount_crypt_stat->global_default_cipher_key_size = 0;
 421         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 422             && !fn_cipher_key_bytes_set)
 423                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
 424                         mount_crypt_stat->global_default_cipher_key_size;
 425
 426         cipher_code = ecryptfs_code_for_cipher_string(
 427                 mount_crypt_stat->global_default_cipher_name,
 428                 mount_crypt_stat->global_default_cipher_key_size);
 429         if (!cipher_code) {
 430                 ecryptfs_printk(KERN_ERR,
 431                                 "eCryptfs doesn't support cipher: %s",
 432                                 mount_crypt_stat->global_default_cipher_name);
 433                 rc = -EINVAL;
 434                 goto out;
 435         }
 436
 437         mutex_lock(&key_tfm_list_mutex);
 438         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
 439                                  NULL)) {
 440                 rc = ecryptfs_add_new_key_tfm(
 441                         NULL, mount_crypt_stat->global_default_cipher_name,
 442                         mount_crypt_stat->global_default_cipher_key_size);
 443                 if (rc) {
 444                         printk(KERN_ERR "Error attempting to initialize "
 445                                "cipher with name = [%s] and key size = [%td]; "
 446                                "rc = [%d]\n",
 447                                mount_crypt_stat->global_default_cipher_name,
 448                                mount_crypt_stat->global_default_cipher_key_size,
 449                                rc);
 450                         rc = -EINVAL;
 451                         mutex_unlock(&key_tfm_list_mutex);
 452                         goto out;
 453                 }
 454         }
 455         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 456             && !ecryptfs_tfm_exists(
 457                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
 458                 rc = ecryptfs_add_new_key_tfm(
 459                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
 460                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
 461                 if (rc) {
 462                         printk(KERN_ERR "Error attempting to initialize "
 463                                "cipher with name = [%s] and key size = [%td]; "
 464                                "rc = [%d]\n",
 465                                mount_crypt_stat->global_default_fn_cipher_name,
 466                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
 467                                rc);
 468                         rc = -EINVAL;
 469                         mutex_unlock(&key_tfm_list_mutex);
 470                         goto out;
 471                 }
 472         }
 473         mutex_unlock(&key_tfm_list_mutex);
 474         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
 475         if (rc)
 476                 printk(KERN_WARNING "One or more global auth toks could not "
 477                        "properly register; rc = [%d]\n", rc);
 478 out:
 479         return rc;
 480 }
 481
 482 struct kmem_cache *ecryptfs_sb_info_cache;
 483 static struct file_system_type ecryptfs_fs_type;
 484
 485 /**
 486  * ecryptfs_get_sb
 487  * @fs_type
 488  * @flags
 489  * @dev_name: The path to mount over
 490  * @raw_data: The options passed into the kernel
 491  */
 492 static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
 493                         const char *dev_name, void *raw_data)
 494 {
 495         struct super_block *s;
 496         struct ecryptfs_sb_info *sbi;
 497         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 498         struct ecryptfs_dentry_info *root_info;
 499         const char *err = "Getting sb failed";
 500         struct inode *inode;
 501         struct path path;
 502         uid_t check_ruid;
 503         int rc;
 504
 505         sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
 506         if (!sbi) {
 507                 rc = -ENOMEM;
 508                 goto out;
 509         }
 510
 511         rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
 512         if (rc) {
 513                 err = "Error parsing options";
 514                 goto out;
 515         }
 516         mount_crypt_stat = &sbi->mount_crypt_stat;
 517
 518         s = sget(fs_type, NULL, set_anon_super, NULL);
 519         if (IS_ERR(s)) {
 520                 rc = PTR_ERR(s);
 521                 goto out;
 522         }
 523
 524         rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY);
 525         if (rc)
 526                 goto out1;
 527
 528         ecryptfs_set_superblock_private(s, sbi);
 529         s->s_bdi = &sbi->bdi;
 530
 531         /* ->kill_sb() will take care of sbi after that point */
 532         sbi = NULL;
 533         s->s_op = &ecryptfs_sops;
 534         s->s_d_op = &ecryptfs_dops;
 535
 536         err = "Reading sb failed";
 537         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 538         if (rc) {
 539                 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
 540                 goto out1;
 541         }
 542         if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
 543                 rc = -EINVAL;
 544                 printk(KERN_ERR "Mount on filesystem of type "
 545                         "eCryptfs explicitly disallowed due to "
 546                         "known incompatibilities\n");
 547                 goto out_free;
 548         }
 549
 550         if (check_ruid && path.dentry->d_inode->i_uid != current_uid()) {
 551                 rc = -EPERM;
 552                 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
 553                        "requested user (uid: %d)\n",
 554                        path.dentry->d_inode->i_uid, current_uid());
 555                 goto out_free;
 556         }
 557
 558         ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
 559
 560         /**
 561          * Set the POSIX ACL flag based on whether they're enabled in the lower
 562          * mount.
 563          */
 564         s->s_flags = flags & ~MS_POSIXACL;
 565         s->s_flags |= path.dentry->d_sb->s_flags & MS_POSIXACL;
 566
 567         /**
 568          * Force a read-only eCryptfs mount when:
 569          *   1) The lower mount is ro
 570          *   2) The ecryptfs_encrypted_view mount option is specified
 571          */
 572         if (path.dentry->d_sb->s_flags & MS_RDONLY ||
 573             mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
 574                 s->s_flags |= MS_RDONLY;
 575
 576         s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 577         s->s_blocksize = path.dentry->d_sb->s_blocksize;
 578         s->s_magic = ECRYPTFS_SUPER_MAGIC;
 579         s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
 580
 581         rc = -EINVAL;
 582         if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
 583                 pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
 584                 goto out_free;
 585         }
 586
 587         inode = ecryptfs_get_inode(path.dentry->d_inode, s);
 588         rc = PTR_ERR(inode);
 589         if (IS_ERR(inode))
 590                 goto out_free;
 591
 592         s->s_root = d_alloc_root(inode);
 593         if (!s->s_root) {
 594                 iput(inode);
 595                 rc = -ENOMEM;
 596                 goto out_free;
 597         }
 598
 599         rc = -ENOMEM;
 600         root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 601         if (!root_info)
 602                 goto out_free;
 603
 604         /* ->kill_sb() will take care of root_info */
 605         ecryptfs_set_dentry_private(s->s_root, root_info);
 606         ecryptfs_set_dentry_lower(s->s_root, path.dentry);
 607         ecryptfs_set_dentry_lower_mnt(s->s_root, path.mnt);
 608
 609         s->s_flags |= MS_ACTIVE;
 610         return dget(s->s_root);
 611
 612 out_free:
 613         path_put(&path);
 614 out1:
 615         deactivate_locked_super(s);
 616 out:
 617         if (sbi) {
 618                 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
 619                 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
 620         }
 621         printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
 622         return ERR_PTR(rc);
 623 }
 624
 625 /**
 626  * ecryptfs_kill_block_super
 627  * @sb: The ecryptfs super block
 628  *
 629  * Used to bring the superblock down and free the private data.
 630  */
 631 static void ecryptfs_kill_block_super(struct super_block *sb)
 632 {
 633         struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
 634         kill_anon_super(sb);
 635         if (!sb_info)
 636                 return;
 637         ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
 638         bdi_destroy(&sb_info->bdi);
 639         kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
 640 }
 641
 642 static struct file_system_type ecryptfs_fs_type = {
 643         .owner = THIS_MODULE,
 644         .name = "ecryptfs",
 645         .mount = ecryptfs_mount,
 646         .kill_sb = ecryptfs_kill_block_super,
 647         .fs_flags = 0
 648 };
 649
 650 /**
 651  * inode_info_init_once
 652  *
 653  * Initializes the ecryptfs_inode_info_cache when it is created
 654  */
 655 static void
 656 inode_info_init_once(void *vptr)
 657 {
 658         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 659
 660         inode_init_once(&ei->vfs_inode);
 661 }
 662
 663 static struct ecryptfs_cache_info {
 664         struct kmem_cache **cache;
 665         const char *name;
 666         size_t size;
 667         void (*ctor)(void *obj);
 668 } ecryptfs_cache_infos[] = {
 669         {
 670                 .cache = &ecryptfs_auth_tok_list_item_cache,
 671                 .name = "ecryptfs_auth_tok_list_item",
 672                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 673         },
 674         {
 675                 .cache = &ecryptfs_file_info_cache,
 676                 .name = "ecryptfs_file_cache",
 677                 .size = sizeof(struct ecryptfs_file_info),
 678         },
 679         {
 680                 .cache = &ecryptfs_dentry_info_cache,
 681                 .name = "ecryptfs_dentry_info_cache",
 682                 .size = sizeof(struct ecryptfs_dentry_info),
 683         },
 684         {
 685                 .cache = &ecryptfs_inode_info_cache,
 686                 .name = "ecryptfs_inode_cache",
 687                 .size = sizeof(struct ecryptfs_inode_info),
 688                 .ctor = inode_info_init_once,
 689         },
 690         {
 691                 .cache = &ecryptfs_sb_info_cache,
 692                 .name = "ecryptfs_sb_cache",
 693                 .size = sizeof(struct ecryptfs_sb_info),
 694         },
 695         {
 696                 .cache = &ecryptfs_header_cache,
 697                 .name = "ecryptfs_headers",
 698                 .size = PAGE_CACHE_SIZE,
 699         },
 700         {
 701                 .cache = &ecryptfs_xattr_cache,
 702                 .name = "ecryptfs_xattr_cache",
 703                 .size = PAGE_CACHE_SIZE,
 704         },
 705         {
 706                 .cache = &ecryptfs_key_record_cache,
 707                 .name = "ecryptfs_key_record_cache",
 708                 .size = sizeof(struct ecryptfs_key_record),
 709         },
 710         {
 711                 .cache = &ecryptfs_key_sig_cache,
 712                 .name = "ecryptfs_key_sig_cache",
 713                 .size = sizeof(struct ecryptfs_key_sig),
 714         },
 715         {
 716                 .cache = &ecryptfs_global_auth_tok_cache,
 717                 .name = "ecryptfs_global_auth_tok_cache",
 718                 .size = sizeof(struct ecryptfs_global_auth_tok),
 719         },
 720         {
 721                 .cache = &ecryptfs_key_tfm_cache,
 722                 .name = "ecryptfs_key_tfm_cache",
 723                 .size = sizeof(struct ecryptfs_key_tfm),
 724         },
 725         {
 726                 .cache = &ecryptfs_open_req_cache,
 727                 .name = "ecryptfs_open_req_cache",
 728                 .size = sizeof(struct ecryptfs_open_req),
 729         },
 730 };
 731
 732 static void ecryptfs_free_kmem_caches(void)
 733 {
 734         int i;
 735
 736         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 737                 struct ecryptfs_cache_info *info;
 738
 739                 info = &ecryptfs_cache_infos[i];
 740                 if (*(info->cache))
 741                         kmem_cache_destroy(*(info->cache));
 742         }
 743 }
 744
 745 /**
 746  * ecryptfs_init_kmem_caches
 747  *
 748  * Returns zero on success; non-zero otherwise
 749  */
 750 static int ecryptfs_init_kmem_caches(void)
 751 {
 752         int i;
 753
 754         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 755                 struct ecryptfs_cache_info *info;
 756
 757                 info = &ecryptfs_cache_infos[i];
 758                 *(info->cache) = kmem_cache_create(info->name, info->size,
 759                                 0, SLAB_HWCACHE_ALIGN, info->ctor);
 760                 if (!*(info->cache)) {
 761                         ecryptfs_free_kmem_caches();
 762                         ecryptfs_printk(KERN_WARNING, "%s: "
 763                                         "kmem_cache_create failed\n",
 764                                         info->name);
 765                         return -ENOMEM;
 766                 }
 767         }
 768         return 0;
 769 }
 770
 771 static struct kobject *ecryptfs_kobj;
 772
 773 static ssize_t version_show(struct kobject *kobj,
 774                             struct kobj_attribute *attr, char *buff)
 775 {
 776         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 777 }
 778
 779 static struct kobj_attribute version_attr = __ATTR_RO(version);
 780
 781 static struct attribute *attributes[] = {
 782         &version_attr.attr,
 783         NULL,
 784 };
 785
 786 static struct attribute_group attr_group = {
 787         .attrs = attributes,
 788 };
 789
 790 static int do_sysfs_registration(void)
 791 {
 792         int rc;
 793
 794         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 795         if (!ecryptfs_kobj) {
 796                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
 797                 rc = -ENOMEM;
 798                 goto out;
 799         }
 800         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 801         if (rc) {
 802                 printk(KERN_ERR
 803                        "Unable to create ecryptfs version attributes\n");
 804                 kobject_put(ecryptfs_kobj);
 805         }
 806 out:
 807         return rc;
 808 }
 809
 810 static void do_sysfs_unregistration(void)
 811 {
 812         sysfs_remove_group(ecryptfs_kobj, &attr_group);
 813         kobject_put(ecryptfs_kobj);
 814 }
 815
 816 static int __init ecryptfs_init(void)
 817 {
 818         int rc;
 819
 820         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
 821                 rc = -EINVAL;
 822                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 823                                 "larger than the host's page size, and so "
 824                                 "eCryptfs cannot run on this system. The "
 825                                 "default eCryptfs extent size is [%u] bytes; "
 826                                 "the page size is [%lu] bytes.\n",
 827                                 ECRYPTFS_DEFAULT_EXTENT_SIZE,
 828                                 (unsigned long)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                 goto out_free_kmem_caches;
 841         }
 842         rc = do_sysfs_registration();
 843         if (rc) {
 844                 printk(KERN_ERR "sysfs registration failed\n");
 845                 goto out_unregister_filesystem;
 846         }
 847         rc = ecryptfs_init_kthread();
 848         if (rc) {
 849                 printk(KERN_ERR "%s: kthread initialization failed; "
 850                        "rc = [%d]\n", __func__, rc);
 851                 goto out_do_sysfs_unregistration;
 852         }
 853         rc = ecryptfs_init_messaging();
 854         if (rc) {
 855                 printk(KERN_ERR "Failure occurred while attempting to "
 856                                 "initialize the communications channel to "
 857                                 "ecryptfsd\n");
 858                 goto out_destroy_kthread;
 859         }
 860         rc = ecryptfs_init_crypto();
 861         if (rc) {
 862                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
 863                        "rc = [%d]\n", rc);
 864                 goto out_release_messaging;
 865         }
 866         if (ecryptfs_verbosity > 0)
 867                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 868                         "will be written to the syslog!\n", ecryptfs_verbosity);
 869
 870         goto out;
 871 out_release_messaging:
 872         ecryptfs_release_messaging();
 873 out_destroy_kthread:
 874         ecryptfs_destroy_kthread();
 875 out_do_sysfs_unregistration:
 876         do_sysfs_unregistration();
 877 out_unregister_filesystem:
 878         unregister_filesystem(&ecryptfs_fs_type);
 879 out_free_kmem_caches:
 880         ecryptfs_free_kmem_caches();
 881 out:
 882         return rc;
 883 }
 884
 885 static void __exit ecryptfs_exit(void)
 886 {
 887         int rc;
 888
 889         rc = ecryptfs_destroy_crypto();
 890         if (rc)
 891                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 892                        "rc = [%d]\n", rc);
 893         ecryptfs_release_messaging();
 894         ecryptfs_destroy_kthread();
 895         do_sysfs_unregistration();
 896         unregister_filesystem(&ecryptfs_fs_type);
 897         ecryptfs_free_kmem_caches();
 898 }
 899
 900 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 901 MODULE_DESCRIPTION("eCryptfs");
 902
 903 MODULE_LICENSE("GPL");
 904
 905 module_init(ecryptfs_init)
 906 module_exit(ecryptfs_exit)