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_dentry_info *root_info;
 498         const char *err = "Getting sb failed";
 499         struct inode *inode;
 500         struct path path;
 501         uid_t check_ruid;
 502         int rc;
 503
 504         sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
 505         if (!sbi) {
 506                 rc = -ENOMEM;
 507                 goto out;
 508         }
 509
 510         rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
 511         if (rc) {
 512                 err = "Error parsing options";
 513                 goto out;
 514         }
 515
 516         s = sget(fs_type, NULL, set_anon_super, flags, NULL);
 517         if (IS_ERR(s)) {
 518                 rc = PTR_ERR(s);
 519                 goto out;
 520         }
 521
 522         rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY);
 523         if (rc)
 524                 goto out1;
 525
 526         ecryptfs_set_superblock_private(s, sbi);
 527         s->s_bdi = &sbi->bdi;
 528
 529         /* ->kill_sb() will take care of sbi after that point */
 530         sbi = NULL;
 531         s->s_op = &ecryptfs_sops;
 532         s->s_d_op = &ecryptfs_dops;
 533
 534         err = "Reading sb failed";
 535         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 536         if (rc) {
 537                 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
 538                 goto out1;
 539         }
 540         if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
 541                 rc = -EINVAL;
 542                 printk(KERN_ERR "Mount on filesystem of type "
 543                         "eCryptfs explicitly disallowed due to "
 544                         "known incompatibilities\n");
 545                 goto out_free;
 546         }
 547
 548         if (check_ruid && !uid_eq(path.dentry->d_inode->i_uid, current_uid())) {
 549                 rc = -EPERM;
 550                 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
 551                        "requested user (uid: %d)\n",
 552                         i_uid_read(path.dentry->d_inode),
 553                         from_kuid(&init_user_ns, current_uid()));
 554                 goto out_free;
 555         }
 556
 557         ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
 558
 559         /**
 560          * Set the POSIX ACL flag based on whether they're enabled in the lower
 561          * mount. Force a read-only eCryptfs mount if the lower mount is ro.
 562          * Allow a ro eCryptfs mount even when the lower mount is rw.
 563          */
 564         s->s_flags = flags & ~MS_POSIXACL;
 565         s->s_flags |= path.dentry->d_sb->s_flags & (MS_RDONLY | MS_POSIXACL);
 566
 567         s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 568         s->s_blocksize = path.dentry->d_sb->s_blocksize;
 569         s->s_magic = ECRYPTFS_SUPER_MAGIC;
 570
 571         inode = ecryptfs_get_inode(path.dentry->d_inode, s);
 572         rc = PTR_ERR(inode);
 573         if (IS_ERR(inode))
 574                 goto out_free;
 575
 576         s->s_root = d_make_root(inode);
 577         if (!s->s_root) {
 578                 rc = -ENOMEM;
 579                 goto out_free;
 580         }
 581
 582         rc = -ENOMEM;
 583         root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 584         if (!root_info)
 585                 goto out_free;
 586
 587         /* ->kill_sb() will take care of root_info */
 588         ecryptfs_set_dentry_private(s->s_root, root_info);
 589         ecryptfs_set_dentry_lower(s->s_root, path.dentry);
 590         ecryptfs_set_dentry_lower_mnt(s->s_root, path.mnt);
 591
 592         s->s_flags |= MS_ACTIVE;
 593         return dget(s->s_root);
 594
 595 out_free:
 596         path_put(&path);
 597 out1:
 598         deactivate_locked_super(s);
 599 out:
 600         if (sbi) {
 601                 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
 602                 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
 603         }
 604         printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
 605         return ERR_PTR(rc);
 606 }
 607
 608 /**
 609  * ecryptfs_kill_block_super
 610  * @sb: The ecryptfs super block
 611  *
 612  * Used to bring the superblock down and free the private data.
 613  */
 614 static void ecryptfs_kill_block_super(struct super_block *sb)
 615 {
 616         struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
 617         kill_anon_super(sb);
 618         if (!sb_info)
 619                 return;
 620         ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
 621         bdi_destroy(&sb_info->bdi);
 622         kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
 623 }
 624
 625 static struct file_system_type ecryptfs_fs_type = {
 626         .owner = THIS_MODULE,
 627         .name = "ecryptfs",
 628         .mount = ecryptfs_mount,
 629         .kill_sb = ecryptfs_kill_block_super,
 630         .fs_flags = 0
 631 };
 632 MODULE_ALIAS_FS("ecryptfs");
 633
 634 /**
 635  * inode_info_init_once
 636  *
 637  * Initializes the ecryptfs_inode_info_cache when it is created
 638  */
 639 static void
 640 inode_info_init_once(void *vptr)
 641 {
 642         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 643
 644         inode_init_once(&ei->vfs_inode);
 645 }
 646
 647 static struct ecryptfs_cache_info {
 648         struct kmem_cache **cache;
 649         const char *name;
 650         size_t size;
 651         void (*ctor)(void *obj);
 652 } ecryptfs_cache_infos[] = {
 653         {
 654                 .cache = &ecryptfs_auth_tok_list_item_cache,
 655                 .name = "ecryptfs_auth_tok_list_item",
 656                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 657         },
 658         {
 659                 .cache = &ecryptfs_file_info_cache,
 660                 .name = "ecryptfs_file_cache",
 661                 .size = sizeof(struct ecryptfs_file_info),
 662         },
 663         {
 664                 .cache = &ecryptfs_dentry_info_cache,
 665                 .name = "ecryptfs_dentry_info_cache",
 666                 .size = sizeof(struct ecryptfs_dentry_info),
 667         },
 668         {
 669                 .cache = &ecryptfs_inode_info_cache,
 670                 .name = "ecryptfs_inode_cache",
 671                 .size = sizeof(struct ecryptfs_inode_info),
 672                 .ctor = inode_info_init_once,
 673         },
 674         {
 675                 .cache = &ecryptfs_sb_info_cache,
 676                 .name = "ecryptfs_sb_cache",
 677                 .size = sizeof(struct ecryptfs_sb_info),
 678         },
 679         {
 680                 .cache = &ecryptfs_header_cache,
 681                 .name = "ecryptfs_headers",
 682                 .size = PAGE_CACHE_SIZE,
 683         },
 684         {
 685                 .cache = &ecryptfs_xattr_cache,
 686                 .name = "ecryptfs_xattr_cache",
 687                 .size = PAGE_CACHE_SIZE,
 688         },
 689         {
 690                 .cache = &ecryptfs_key_record_cache,
 691                 .name = "ecryptfs_key_record_cache",
 692                 .size = sizeof(struct ecryptfs_key_record),
 693         },
 694         {
 695                 .cache = &ecryptfs_key_sig_cache,
 696                 .name = "ecryptfs_key_sig_cache",
 697                 .size = sizeof(struct ecryptfs_key_sig),
 698         },
 699         {
 700                 .cache = &ecryptfs_global_auth_tok_cache,
 701                 .name = "ecryptfs_global_auth_tok_cache",
 702                 .size = sizeof(struct ecryptfs_global_auth_tok),
 703         },
 704         {
 705                 .cache = &ecryptfs_key_tfm_cache,
 706                 .name = "ecryptfs_key_tfm_cache",
 707                 .size = sizeof(struct ecryptfs_key_tfm),
 708         },
 709 };
 710
 711 static void ecryptfs_free_kmem_caches(void)
 712 {
 713         int i;
 714
 715         /*
 716          * Make sure all delayed rcu free inodes are flushed before we
 717          * destroy cache.
 718          */
 719         rcu_barrier();
 720
 721         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 722                 struct ecryptfs_cache_info *info;
 723
 724                 info = &ecryptfs_cache_infos[i];
 725                 if (*(info->cache))
 726                         kmem_cache_destroy(*(info->cache));
 727         }
 728 }
 729
 730 /**
 731  * ecryptfs_init_kmem_caches
 732  *
 733  * Returns zero on success; non-zero otherwise
 734  */
 735 static int ecryptfs_init_kmem_caches(void)
 736 {
 737         int i;
 738
 739         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 740                 struct ecryptfs_cache_info *info;
 741
 742                 info = &ecryptfs_cache_infos[i];
 743                 *(info->cache) = kmem_cache_create(info->name, info->size,
 744                                 0, SLAB_HWCACHE_ALIGN, info->ctor);
 745                 if (!*(info->cache)) {
 746                         ecryptfs_free_kmem_caches();
 747                         ecryptfs_printk(KERN_WARNING, "%s: "
 748                                         "kmem_cache_create failed\n",
 749                                         info->name);
 750                         return -ENOMEM;
 751                 }
 752         }
 753         return 0;
 754 }
 755
 756 static struct kobject *ecryptfs_kobj;
 757
 758 static ssize_t version_show(struct kobject *kobj,
 759                             struct kobj_attribute *attr, char *buff)
 760 {
 761         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 762 }
 763
 764 static struct kobj_attribute version_attr = __ATTR_RO(version);
 765
 766 static struct attribute *attributes[] = {
 767         &version_attr.attr,
 768         NULL,
 769 };
 770
 771 static struct attribute_group attr_group = {
 772         .attrs = attributes,
 773 };
 774
 775 static int do_sysfs_registration(void)
 776 {
 777         int rc;
 778
 779         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 780         if (!ecryptfs_kobj) {
 781                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
 782                 rc = -ENOMEM;
 783                 goto out;
 784         }
 785         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 786         if (rc) {
 787                 printk(KERN_ERR
 788                        "Unable to create ecryptfs version attributes\n");
 789                 kobject_put(ecryptfs_kobj);
 790         }
 791 out:
 792         return rc;
 793 }
 794
 795 static void do_sysfs_unregistration(void)
 796 {
 797         sysfs_remove_group(ecryptfs_kobj, &attr_group);
 798         kobject_put(ecryptfs_kobj);
 799 }
 800
 801 static int __init ecryptfs_init(void)
 802 {
 803         int rc;
 804
 805         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
 806                 rc = -EINVAL;
 807                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 808                                 "larger than the host's page size, and so "
 809                                 "eCryptfs cannot run on this system. The "
 810                                 "default eCryptfs extent size is [%u] bytes; "
 811                                 "the page size is [%lu] bytes.\n",
 812                                 ECRYPTFS_DEFAULT_EXTENT_SIZE,
 813                                 (unsigned long)PAGE_CACHE_SIZE);
 814                 goto out;
 815         }
 816         rc = ecryptfs_init_kmem_caches();
 817         if (rc) {
 818                 printk(KERN_ERR
 819                        "Failed to allocate one or more kmem_cache objects\n");
 820                 goto out;
 821         }
 822         rc = do_sysfs_registration();
 823         if (rc) {
 824                 printk(KERN_ERR "sysfs registration failed\n");
 825                 goto out_free_kmem_caches;
 826         }
 827         rc = ecryptfs_init_kthread();
 828         if (rc) {
 829                 printk(KERN_ERR "%s: kthread initialization failed; "
 830                        "rc = [%d]\n", __func__, rc);
 831                 goto out_do_sysfs_unregistration;
 832         }
 833         rc = ecryptfs_init_messaging();
 834         if (rc) {
 835                 printk(KERN_ERR "Failure occurred while attempting to "
 836                                 "initialize the communications channel to "
 837                                 "ecryptfsd\n");
 838                 goto out_destroy_kthread;
 839         }
 840         rc = ecryptfs_init_crypto();
 841         if (rc) {
 842                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
 843                        "rc = [%d]\n", rc);
 844                 goto out_release_messaging;
 845         }
 846         rc = register_filesystem(&ecryptfs_fs_type);
 847         if (rc) {
 848                 printk(KERN_ERR "Failed to register filesystem\n");
 849                 goto out_destroy_crypto;
 850         }
 851         if (ecryptfs_verbosity > 0)
 852                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 853                         "will be written to the syslog!\n", ecryptfs_verbosity);
 854
 855         goto out;
 856 out_destroy_crypto:
 857         ecryptfs_destroy_crypto();
 858 out_release_messaging:
 859         ecryptfs_release_messaging();
 860 out_destroy_kthread:
 861         ecryptfs_destroy_kthread();
 862 out_do_sysfs_unregistration:
 863         do_sysfs_unregistration();
 864 out_free_kmem_caches:
 865         ecryptfs_free_kmem_caches();
 866 out:
 867         return rc;
 868 }
 869
 870 static void __exit ecryptfs_exit(void)
 871 {
 872         int rc;
 873
 874         rc = ecryptfs_destroy_crypto();
 875         if (rc)
 876                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 877                        "rc = [%d]\n", rc);
 878         ecryptfs_release_messaging();
 879         ecryptfs_destroy_kthread();
 880         do_sysfs_unregistration();
 881         unregister_filesystem(&ecryptfs_fs_type);
 882         ecryptfs_free_kmem_caches();
 883 }
 884
 885 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 886 MODULE_DESCRIPTION("eCryptfs");
 887
 888 MODULE_LICENSE("GPL");
 889
 890 module_init(ecryptfs_init)
 891 module_exit(ecryptfs_exit)