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/ima.h>
  39 #include "ecryptfs_kernel.h"
  40
  41 /**
  42  * Module parameter that defines the ecryptfs_verbosity level.
  43  */
  44 int ecryptfs_verbosity = 0;
  45
  46 module_param(ecryptfs_verbosity, int, 0);
  47 MODULE_PARM_DESC(ecryptfs_verbosity,
  48                  "Initial verbosity level (0 or 1; defaults to "
  49                  "0, which is Quiet)");
  50
  51 /**
  52  * Module parameter that defines the number of message buffer elements
  53  */
  54 unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
  55
  56 module_param(ecryptfs_message_buf_len, uint, 0);
  57 MODULE_PARM_DESC(ecryptfs_message_buf_len,
  58                  "Number of message buffer elements");
  59
  60 /**
  61  * Module parameter that defines the maximum guaranteed amount of time to wait
  62  * for a response from ecryptfsd.  The actual sleep time will be, more than
  63  * likely, a small amount greater than this specified value, but only less if
  64  * the message successfully arrives.
  65  */
  66 signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
  67
  68 module_param(ecryptfs_message_wait_timeout, long, 0);
  69 MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
  70                  "Maximum number of seconds that an operation will "
  71                  "sleep while waiting for a message response from "
  72                  "userspace");
  73
  74 /**
  75  * Module parameter that is an estimate of the maximum number of users
  76  * that will be concurrently using eCryptfs. Set this to the right
  77  * value to balance performance and memory use.
  78  */
  79 unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
  80
  81 module_param(ecryptfs_number_of_users, uint, 0);
  82 MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
  83                  "concurrent users of eCryptfs");
  84
  85 void __ecryptfs_printk(const char *fmt, ...)
  86 {
  87         va_list args;
  88         va_start(args, fmt);
  89         if (fmt[1] == '7') { /* KERN_DEBUG */
  90                 if (ecryptfs_verbosity >= 1)
  91                         vprintk(fmt, args);
  92         } else
  93                 vprintk(fmt, args);
  94         va_end(args);
  95 }
  96
  97 /**
  98  * ecryptfs_init_persistent_file
  99  * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
 100  *                   the lower dentry and the lower mount set
 101  *
 102  * eCryptfs only ever keeps a single open file for every lower
 103  * inode. All I/O operations to the lower inode occur through that
 104  * file. When the first eCryptfs dentry that interposes with the first
 105  * lower dentry for that inode is created, this function creates the
 106  * persistent file struct and associates it with the eCryptfs
 107  * inode. When the eCryptfs inode is destroyed, the file is closed.
 108  *
 109  * The persistent file will be opened with read/write permissions, if
 110  * possible. Otherwise, it is opened read-only.
 111  *
 112  * This function does nothing if a lower persistent file is already
 113  * associated with the eCryptfs inode.
 114  *
 115  * Returns zero on success; non-zero otherwise
 116  */
 117 int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry)
 118 {
 119         const struct cred *cred = current_cred();
 120         struct ecryptfs_inode_info *inode_info =
 121                 ecryptfs_inode_to_private(ecryptfs_dentry->d_inode);
 122         int opened_lower_file = 0;
 123         int rc = 0;
 124
 125         mutex_lock(&inode_info->lower_file_mutex);
 126         if (!inode_info->lower_file) {
 127                 struct dentry *lower_dentry;
 128                 struct vfsmount *lower_mnt =
 129                         ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
 130
 131                 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 132                 rc = ecryptfs_privileged_open(&inode_info->lower_file,
 133                                               lower_dentry, lower_mnt, cred);
 134                 if (rc) {
 135                         printk(KERN_ERR "Error opening lower persistent file "
 136                                "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
 137                                "rc = [%d]\n", lower_dentry, lower_mnt, rc);
 138                         inode_info->lower_file = NULL;
 139                 } else
 140                         opened_lower_file = 1;
 141         }
 142         mutex_unlock(&inode_info->lower_file_mutex);
 143         if (opened_lower_file)
 144                 ima_counts_get(inode_info->lower_file);
 145         return rc;
 146 }
 147
 148 /**
 149  * ecryptfs_interpose
 150  * @lower_dentry: Existing dentry in the lower filesystem
 151  * @dentry: ecryptfs' dentry
 152  * @sb: ecryptfs's super_block
 153  * @flags: flags to govern behavior of interpose procedure
 154  *
 155  * Interposes upper and lower dentries.
 156  *
 157  * Returns zero on success; non-zero otherwise
 158  */
 159 int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
 160                        struct super_block *sb, u32 flags)
 161 {
 162         struct inode *lower_inode;
 163         struct inode *inode;
 164         int rc = 0;
 165
 166         lower_inode = lower_dentry->d_inode;
 167         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) {
 168                 rc = -EXDEV;
 169                 goto out;
 170         }
 171         if (!igrab(lower_inode)) {
 172                 rc = -ESTALE;
 173                 goto out;
 174         }
 175         inode = iget5_locked(sb, (unsigned long)lower_inode,
 176                              ecryptfs_inode_test, ecryptfs_inode_set,
 177                              lower_inode);
 178         if (!inode) {
 179                 rc = -EACCES;
 180                 iput(lower_inode);
 181                 goto out;
 182         }
 183         if (inode->i_state & I_NEW)
 184                 unlock_new_inode(inode);
 185         else
 186                 iput(lower_inode);
 187         if (S_ISLNK(lower_inode->i_mode))
 188                 inode->i_op = &ecryptfs_symlink_iops;
 189         else if (S_ISDIR(lower_inode->i_mode))
 190                 inode->i_op = &ecryptfs_dir_iops;
 191         if (S_ISDIR(lower_inode->i_mode))
 192                 inode->i_fop = &ecryptfs_dir_fops;
 193         if (special_file(lower_inode->i_mode))
 194                 init_special_inode(inode, lower_inode->i_mode,
 195                                    lower_inode->i_rdev);
 196         dentry->d_op = &ecryptfs_dops;
 197         fsstack_copy_attr_all(inode, lower_inode, NULL);
 198         /* This size will be overwritten for real files w/ headers and
 199          * other metadata */
 200         fsstack_copy_inode_size(inode, lower_inode);
 201         if (flags & ECRYPTFS_INTERPOSE_FLAG_D_ADD)
 202                 d_add(dentry, inode);
 203         else
 204                 d_instantiate(dentry, inode);
 205 out:
 206         return rc;
 207 }
 208
 209 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
 210        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
 211        ecryptfs_opt_ecryptfs_key_bytes,
 212        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
 213        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
 214        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
 215        ecryptfs_opt_unlink_sigs, ecryptfs_opt_check_dev_ruid,
 216        ecryptfs_opt_err };
 217
 218 static const match_table_t tokens = {
 219         {ecryptfs_opt_sig, "sig=%s"},
 220         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 221         {ecryptfs_opt_cipher, "cipher=%s"},
 222         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
 223         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
 224         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
 225         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
 226         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
 227         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
 228         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
 229         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
 230         {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
 231         {ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
 232         {ecryptfs_opt_err, NULL}
 233 };
 234
 235 static int ecryptfs_init_global_auth_toks(
 236         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 237 {
 238         struct ecryptfs_global_auth_tok *global_auth_tok;
 239         int rc = 0;
 240
 241         list_for_each_entry(global_auth_tok,
 242                             &mount_crypt_stat->global_auth_tok_list,
 243                             mount_crypt_stat_list) {
 244                 rc = ecryptfs_keyring_auth_tok_for_sig(
 245                         &global_auth_tok->global_auth_tok_key,
 246                         &global_auth_tok->global_auth_tok,
 247                         global_auth_tok->sig);
 248                 if (rc) {
 249                         printk(KERN_ERR "Could not find valid key in user "
 250                                "session keyring for sig specified in mount "
 251                                "option: [%s]\n", global_auth_tok->sig);
 252                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 253                         goto out;
 254                 } else
 255                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
 256         }
 257 out:
 258         return rc;
 259 }
 260
 261 static void ecryptfs_init_mount_crypt_stat(
 262         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 263 {
 264         memset((void *)mount_crypt_stat, 0,
 265                sizeof(struct ecryptfs_mount_crypt_stat));
 266         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
 267         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
 268         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
 269 }
 270
 271 /**
 272  * ecryptfs_parse_options
 273  * @sb: The ecryptfs super block
 274  * @options: The options pased to the kernel
 275  * @check_ruid: set to 1 if device uid should be checked against the ruid
 276  *
 277  * Parse mount options:
 278  * debug=N         - ecryptfs_verbosity level for debug output
 279  * sig=XXX         - description(signature) of the key to use
 280  *
 281  * Returns the dentry object of the lower-level (lower/interposed)
 282  * directory; We want to mount our stackable file system on top of
 283  * that lower directory.
 284  *
 285  * The signature of the key to use must be the description of a key
 286  * already in the keyring. Mounting will fail if the key can not be
 287  * found.
 288  *
 289  * Returns zero on success; non-zero on error
 290  */
 291 static int ecryptfs_parse_options(struct super_block *sb, char *options,
 292                                         uid_t *check_ruid)
 293 {
 294         char *p;
 295         int rc = 0;
 296         int sig_set = 0;
 297         int cipher_name_set = 0;
 298         int fn_cipher_name_set = 0;
 299         int cipher_key_bytes;
 300         int cipher_key_bytes_set = 0;
 301         int fn_cipher_key_bytes;
 302         int fn_cipher_key_bytes_set = 0;
 303         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 304                 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
 305         substring_t args[MAX_OPT_ARGS];
 306         int token;
 307         char *sig_src;
 308         char *cipher_name_dst;
 309         char *cipher_name_src;
 310         char *fn_cipher_name_dst;
 311         char *fn_cipher_name_src;
 312         char *fnek_dst;
 313         char *fnek_src;
 314         char *cipher_key_bytes_src;
 315         char *fn_cipher_key_bytes_src;
 316
 317         *check_ruid = 0;
 318
 319         if (!options) {
 320                 rc = -EINVAL;
 321                 goto out;
 322         }
 323         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
 324         while ((p = strsep(&options, ",")) != NULL) {
 325                 if (!*p)
 326                         continue;
 327                 token = match_token(p, tokens, args);
 328                 switch (token) {
 329                 case ecryptfs_opt_sig:
 330                 case ecryptfs_opt_ecryptfs_sig:
 331                         sig_src = args[0].from;
 332                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
 333                                                           sig_src, 0);
 334                         if (rc) {
 335                                 printk(KERN_ERR "Error attempting to register "
 336                                        "global sig; rc = [%d]\n", rc);
 337                                 goto out;
 338                         }
 339                         sig_set = 1;
 340                         break;
 341                 case ecryptfs_opt_cipher:
 342                 case ecryptfs_opt_ecryptfs_cipher:
 343                         cipher_name_src = args[0].from;
 344                         cipher_name_dst =
 345                                 mount_crypt_stat->
 346                                 global_default_cipher_name;
 347                         strncpy(cipher_name_dst, cipher_name_src,
 348                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 349                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 350                         cipher_name_set = 1;
 351                         break;
 352                 case ecryptfs_opt_ecryptfs_key_bytes:
 353                         cipher_key_bytes_src = args[0].from;
 354                         cipher_key_bytes =
 355                                 (int)simple_strtol(cipher_key_bytes_src,
 356                                                    &cipher_key_bytes_src, 0);
 357                         mount_crypt_stat->global_default_cipher_key_size =
 358                                 cipher_key_bytes;
 359                         cipher_key_bytes_set = 1;
 360                         break;
 361                 case ecryptfs_opt_passthrough:
 362                         mount_crypt_stat->flags |=
 363                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 364                         break;
 365                 case ecryptfs_opt_xattr_metadata:
 366                         mount_crypt_stat->flags |=
 367                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 368                         break;
 369                 case ecryptfs_opt_encrypted_view:
 370                         mount_crypt_stat->flags |=
 371                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 372                         mount_crypt_stat->flags |=
 373                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 374                         break;
 375                 case ecryptfs_opt_fnek_sig:
 376                         fnek_src = args[0].from;
 377                         fnek_dst =
 378                                 mount_crypt_stat->global_default_fnek_sig;
 379                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
 380                         mount_crypt_stat->global_default_fnek_sig[
 381                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
 382                         rc = ecryptfs_add_global_auth_tok(
 383                                 mount_crypt_stat,
 384                                 mount_crypt_stat->global_default_fnek_sig,
 385                                 ECRYPTFS_AUTH_TOK_FNEK);
 386                         if (rc) {
 387                                 printk(KERN_ERR "Error attempting to register "
 388                                        "global fnek sig [%s]; rc = [%d]\n",
 389                                        mount_crypt_stat->global_default_fnek_sig,
 390                                        rc);
 391                                 goto out;
 392                         }
 393                         mount_crypt_stat->flags |=
 394                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 395                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 396                         break;
 397                 case ecryptfs_opt_fn_cipher:
 398                         fn_cipher_name_src = args[0].from;
 399                         fn_cipher_name_dst =
 400                                 mount_crypt_stat->global_default_fn_cipher_name;
 401                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
 402                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 403                         mount_crypt_stat->global_default_fn_cipher_name[
 404                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 405                         fn_cipher_name_set = 1;
 406                         break;
 407                 case ecryptfs_opt_fn_cipher_key_bytes:
 408                         fn_cipher_key_bytes_src = args[0].from;
 409                         fn_cipher_key_bytes =
 410                                 (int)simple_strtol(fn_cipher_key_bytes_src,
 411                                                    &fn_cipher_key_bytes_src, 0);
 412                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
 413                                 fn_cipher_key_bytes;
 414                         fn_cipher_key_bytes_set = 1;
 415                         break;
 416                 case ecryptfs_opt_unlink_sigs:
 417                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
 418                         break;
 419                 case ecryptfs_opt_check_dev_ruid:
 420                         *check_ruid = 1;
 421                         break;
 422                 case ecryptfs_opt_err:
 423                 default:
 424                         printk(KERN_WARNING
 425                                "%s: eCryptfs: unrecognized option [%s]\n",
 426                                __func__, p);
 427                 }
 428         }
 429         if (!sig_set) {
 430                 rc = -EINVAL;
 431                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
 432                                 "auth tok signature as a mount "
 433                                 "parameter; see the eCryptfs README\n");
 434                 goto out;
 435         }
 436         if (!cipher_name_set) {
 437                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 438
 439                 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 440                 strcpy(mount_crypt_stat->global_default_cipher_name,
 441                        ECRYPTFS_DEFAULT_CIPHER);
 442         }
 443         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 444             && !fn_cipher_name_set)
 445                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
 446                        mount_crypt_stat->global_default_cipher_name);
 447         if (!cipher_key_bytes_set)
 448                 mount_crypt_stat->global_default_cipher_key_size = 0;
 449         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 450             && !fn_cipher_key_bytes_set)
 451                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
 452                         mount_crypt_stat->global_default_cipher_key_size;
 453         mutex_lock(&key_tfm_list_mutex);
 454         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
 455                                  NULL)) {
 456                 rc = ecryptfs_add_new_key_tfm(
 457                         NULL, mount_crypt_stat->global_default_cipher_name,
 458                         mount_crypt_stat->global_default_cipher_key_size);
 459                 if (rc) {
 460                         printk(KERN_ERR "Error attempting to initialize "
 461                                "cipher with name = [%s] and key size = [%td]; "
 462                                "rc = [%d]\n",
 463                                mount_crypt_stat->global_default_cipher_name,
 464                                mount_crypt_stat->global_default_cipher_key_size,
 465                                rc);
 466                         rc = -EINVAL;
 467                         mutex_unlock(&key_tfm_list_mutex);
 468                         goto out;
 469                 }
 470         }
 471         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 472             && !ecryptfs_tfm_exists(
 473                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
 474                 rc = ecryptfs_add_new_key_tfm(
 475                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
 476                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
 477                 if (rc) {
 478                         printk(KERN_ERR "Error attempting to initialize "
 479                                "cipher with name = [%s] and key size = [%td]; "
 480                                "rc = [%d]\n",
 481                                mount_crypt_stat->global_default_fn_cipher_name,
 482                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
 483                                rc);
 484                         rc = -EINVAL;
 485                         mutex_unlock(&key_tfm_list_mutex);
 486                         goto out;
 487                 }
 488         }
 489         mutex_unlock(&key_tfm_list_mutex);
 490         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
 491         if (rc)
 492                 printk(KERN_WARNING "One or more global auth toks could not "
 493                        "properly register; rc = [%d]\n", rc);
 494 out:
 495         return rc;
 496 }
 497
 498 struct kmem_cache *ecryptfs_sb_info_cache;
 499 static struct file_system_type ecryptfs_fs_type;
 500
 501 /**
 502  * ecryptfs_fill_super
 503  * @sb: The ecryptfs super block
 504  * @raw_data: The options passed to mount
 505  * @silent: Not used but required by function prototype
 506  *
 507  * Sets up what we can of the sb, rest is done in ecryptfs_read_super
 508  *
 509  * Returns zero on success; non-zero otherwise
 510  */
 511 static int
 512 ecryptfs_fill_super(struct super_block *sb, void *raw_data, int silent)
 513 {
 514         int rc = 0;
 515
 516         /* Released in ecryptfs_put_super() */
 517         ecryptfs_set_superblock_private(sb,
 518                                         kmem_cache_zalloc(ecryptfs_sb_info_cache,
 519                                                          GFP_KERNEL));
 520         if (!ecryptfs_superblock_to_private(sb)) {
 521                 ecryptfs_printk(KERN_WARNING, "Out of memory\n");
 522                 rc = -ENOMEM;
 523                 goto out;
 524         }
 525         sb->s_op = &ecryptfs_sops;
 526         /* Released through deactivate_super(sb) from get_sb_nodev */
 527         sb->s_root = d_alloc(NULL, &(const struct qstr) {
 528                              .hash = 0,.name = "/",.len = 1});
 529         if (!sb->s_root) {
 530                 ecryptfs_printk(KERN_ERR, "d_alloc failed\n");
 531                 rc = -ENOMEM;
 532                 goto out;
 533         }
 534         sb->s_root->d_op = &ecryptfs_dops;
 535         sb->s_root->d_sb = sb;
 536         sb->s_root->d_parent = sb->s_root;
 537         /* Released in d_release when dput(sb->s_root) is called */
 538         /* through deactivate_super(sb) from get_sb_nodev() */
 539         ecryptfs_set_dentry_private(sb->s_root,
 540                                     kmem_cache_zalloc(ecryptfs_dentry_info_cache,
 541                                                      GFP_KERNEL));
 542         if (!ecryptfs_dentry_to_private(sb->s_root)) {
 543                 ecryptfs_printk(KERN_ERR,
 544                                 "dentry_info_cache alloc failed\n");
 545                 rc = -ENOMEM;
 546                 goto out;
 547         }
 548         rc = 0;
 549 out:
 550         /* Should be able to rely on deactivate_super called from
 551          * get_sb_nodev */
 552         return rc;
 553 }
 554
 555 /**
 556  * ecryptfs_read_super
 557  * @sb: The ecryptfs super block
 558  * @dev_name: The path to mount over
 559  *
 560  * Read the super block of the lower filesystem, and use
 561  * ecryptfs_interpose to create our initial inode and super block
 562  * struct.
 563  */
 564 static int ecryptfs_read_super(struct super_block *sb, const char *dev_name,
 565                                 uid_t check_ruid)
 566 {
 567         struct path path;
 568         int rc;
 569
 570         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 571         if (rc) {
 572                 ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n");
 573                 goto out;
 574         }
 575         if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
 576                 rc = -EINVAL;
 577                 printk(KERN_ERR "Mount on filesystem of type "
 578                         "eCryptfs explicitly disallowed due to "
 579                         "known incompatibilities\n");
 580                 goto out_free;
 581         }
 582
 583         if (check_ruid && path.dentry->d_inode->i_uid != current_uid()) {
 584                 rc = -EPERM;
 585                 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
 586                        "requested user (uid: %d)\n",
 587                        path.dentry->d_inode->i_uid, current_uid());
 588                 goto out_free;
 589         }
 590
 591         ecryptfs_set_superblock_lower(sb, path.dentry->d_sb);
 592         sb->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 593         sb->s_blocksize = path.dentry->d_sb->s_blocksize;
 594         ecryptfs_set_dentry_lower(sb->s_root, path.dentry);
 595         ecryptfs_set_dentry_lower_mnt(sb->s_root, path.mnt);
 596         rc = ecryptfs_interpose(path.dentry, sb->s_root, sb, 0);
 597         if (rc)
 598                 goto out_free;
 599         rc = 0;
 600         goto out;
 601 out_free:
 602         path_put(&path);
 603 out:
 604         return rc;
 605 }
 606
 607 /**
 608  * ecryptfs_get_sb
 609  * @fs_type
 610  * @flags
 611  * @dev_name: The path to mount over
 612  * @raw_data: The options passed into the kernel
 613  *
 614  * The whole ecryptfs_get_sb process is broken into 4 functions:
 615  * ecryptfs_parse_options(): handle options passed to ecryptfs, if any
 616  * ecryptfs_fill_super(): used by get_sb_nodev, fills out the super_block
 617  *                        with as much information as it can before needing
 618  *                        the lower filesystem.
 619  * ecryptfs_read_super(): this accesses the lower filesystem and uses
 620  *                        ecryptfs_interpolate to perform most of the linking
 621  * ecryptfs_interpolate(): links the lower filesystem into ecryptfs
 622  */
 623 static int ecryptfs_get_sb(struct file_system_type *fs_type, int flags,
 624                         const char *dev_name, void *raw_data,
 625                         struct vfsmount *mnt)
 626 {
 627         int rc;
 628         struct super_block *sb;
 629         uid_t check_ruid;
 630
 631         rc = get_sb_nodev(fs_type, flags, raw_data, ecryptfs_fill_super, mnt);
 632         if (rc < 0) {
 633                 printk(KERN_ERR "Getting sb failed; rc = [%d]\n", rc);
 634                 goto out;
 635         }
 636         sb = mnt->mnt_sb;
 637         rc = ecryptfs_parse_options(sb, raw_data, &check_ruid);
 638         if (rc) {
 639                 printk(KERN_ERR "Error parsing options; rc = [%d]\n", rc);
 640                 goto out_abort;
 641         }
 642         rc = ecryptfs_read_super(sb, dev_name, check_ruid);
 643         if (rc) {
 644                 printk(KERN_ERR "Reading sb failed; rc = [%d]\n", rc);
 645                 goto out_abort;
 646         }
 647         goto out;
 648 out_abort:
 649         dput(sb->s_root); /* aka mnt->mnt_root, as set by get_sb_nodev() */
 650         deactivate_locked_super(sb);
 651 out:
 652         return rc;
 653 }
 654
 655 /**
 656  * ecryptfs_kill_block_super
 657  * @sb: The ecryptfs super block
 658  *
 659  * Used to bring the superblock down and free the private data.
 660  * Private data is free'd in ecryptfs_put_super()
 661  */
 662 static void ecryptfs_kill_block_super(struct super_block *sb)
 663 {
 664         generic_shutdown_super(sb);
 665 }
 666
 667 static struct file_system_type ecryptfs_fs_type = {
 668         .owner = THIS_MODULE,
 669         .name = "ecryptfs",
 670         .get_sb = ecryptfs_get_sb,
 671         .kill_sb = ecryptfs_kill_block_super,
 672         .fs_flags = 0
 673 };
 674
 675 /**
 676  * inode_info_init_once
 677  *
 678  * Initializes the ecryptfs_inode_info_cache when it is created
 679  */
 680 static void
 681 inode_info_init_once(void *vptr)
 682 {
 683         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 684
 685         inode_init_once(&ei->vfs_inode);
 686 }
 687
 688 static struct ecryptfs_cache_info {
 689         struct kmem_cache **cache;
 690         const char *name;
 691         size_t size;
 692         void (*ctor)(void *obj);
 693 } ecryptfs_cache_infos[] = {
 694         {
 695                 .cache = &ecryptfs_auth_tok_list_item_cache,
 696                 .name = "ecryptfs_auth_tok_list_item",
 697                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 698         },
 699         {
 700                 .cache = &ecryptfs_file_info_cache,
 701                 .name = "ecryptfs_file_cache",
 702                 .size = sizeof(struct ecryptfs_file_info),
 703         },
 704         {
 705                 .cache = &ecryptfs_dentry_info_cache,
 706                 .name = "ecryptfs_dentry_info_cache",
 707                 .size = sizeof(struct ecryptfs_dentry_info),
 708         },
 709         {
 710                 .cache = &ecryptfs_inode_info_cache,
 711                 .name = "ecryptfs_inode_cache",
 712                 .size = sizeof(struct ecryptfs_inode_info),
 713                 .ctor = inode_info_init_once,
 714         },
 715         {
 716                 .cache = &ecryptfs_sb_info_cache,
 717                 .name = "ecryptfs_sb_cache",
 718                 .size = sizeof(struct ecryptfs_sb_info),
 719         },
 720         {
 721                 .cache = &ecryptfs_header_cache_1,
 722                 .name = "ecryptfs_headers_1",
 723                 .size = PAGE_CACHE_SIZE,
 724         },
 725         {
 726                 .cache = &ecryptfs_header_cache_2,
 727                 .name = "ecryptfs_headers_2",
 728                 .size = PAGE_CACHE_SIZE,
 729         },
 730         {
 731                 .cache = &ecryptfs_xattr_cache,
 732                 .name = "ecryptfs_xattr_cache",
 733                 .size = PAGE_CACHE_SIZE,
 734         },
 735         {
 736                 .cache = &ecryptfs_key_record_cache,
 737                 .name = "ecryptfs_key_record_cache",
 738                 .size = sizeof(struct ecryptfs_key_record),
 739         },
 740         {
 741                 .cache = &ecryptfs_key_sig_cache,
 742                 .name = "ecryptfs_key_sig_cache",
 743                 .size = sizeof(struct ecryptfs_key_sig),
 744         },
 745         {
 746                 .cache = &ecryptfs_global_auth_tok_cache,
 747                 .name = "ecryptfs_global_auth_tok_cache",
 748                 .size = sizeof(struct ecryptfs_global_auth_tok),
 749         },
 750         {
 751                 .cache = &ecryptfs_key_tfm_cache,
 752                 .name = "ecryptfs_key_tfm_cache",
 753                 .size = sizeof(struct ecryptfs_key_tfm),
 754         },
 755         {
 756                 .cache = &ecryptfs_open_req_cache,
 757                 .name = "ecryptfs_open_req_cache",
 758                 .size = sizeof(struct ecryptfs_open_req),
 759         },
 760 };
 761
 762 static void ecryptfs_free_kmem_caches(void)
 763 {
 764         int i;
 765
 766         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 767                 struct ecryptfs_cache_info *info;
 768
 769                 info = &ecryptfs_cache_infos[i];
 770                 if (*(info->cache))
 771                         kmem_cache_destroy(*(info->cache));
 772         }
 773 }
 774
 775 /**
 776  * ecryptfs_init_kmem_caches
 777  *
 778  * Returns zero on success; non-zero otherwise
 779  */
 780 static int ecryptfs_init_kmem_caches(void)
 781 {
 782         int i;
 783
 784         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 785                 struct ecryptfs_cache_info *info;
 786
 787                 info = &ecryptfs_cache_infos[i];
 788                 *(info->cache) = kmem_cache_create(info->name, info->size,
 789                                 0, SLAB_HWCACHE_ALIGN, info->ctor);
 790                 if (!*(info->cache)) {
 791                         ecryptfs_free_kmem_caches();
 792                         ecryptfs_printk(KERN_WARNING, "%s: "
 793                                         "kmem_cache_create failed\n",
 794                                         info->name);
 795                         return -ENOMEM;
 796                 }
 797         }
 798         return 0;
 799 }
 800
 801 static struct kobject *ecryptfs_kobj;
 802
 803 static ssize_t version_show(struct kobject *kobj,
 804                             struct kobj_attribute *attr, char *buff)
 805 {
 806         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 807 }
 808
 809 static struct kobj_attribute version_attr = __ATTR_RO(version);
 810
 811 static struct attribute *attributes[] = {
 812         &version_attr.attr,
 813         NULL,
 814 };
 815
 816 static struct attribute_group attr_group = {
 817         .attrs = attributes,
 818 };
 819
 820 static int do_sysfs_registration(void)
 821 {
 822         int rc;
 823
 824         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 825         if (!ecryptfs_kobj) {
 826                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
 827                 rc = -ENOMEM;
 828                 goto out;
 829         }
 830         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 831         if (rc) {
 832                 printk(KERN_ERR
 833                        "Unable to create ecryptfs version attributes\n");
 834                 kobject_put(ecryptfs_kobj);
 835         }
 836 out:
 837         return rc;
 838 }
 839
 840 static void do_sysfs_unregistration(void)
 841 {
 842         sysfs_remove_group(ecryptfs_kobj, &attr_group);
 843         kobject_put(ecryptfs_kobj);
 844 }
 845
 846 static int __init ecryptfs_init(void)
 847 {
 848         int rc;
 849
 850         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
 851                 rc = -EINVAL;
 852                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 853                                 "larger than the host's page size, and so "
 854                                 "eCryptfs cannot run on this system. The "
 855                                 "default eCryptfs extent size is [%d] bytes; "
 856                                 "the page size is [%d] bytes.\n",
 857                                 ECRYPTFS_DEFAULT_EXTENT_SIZE, PAGE_CACHE_SIZE);
 858                 goto out;
 859         }
 860         rc = ecryptfs_init_kmem_caches();
 861         if (rc) {
 862                 printk(KERN_ERR
 863                        "Failed to allocate one or more kmem_cache objects\n");
 864                 goto out;
 865         }
 866         rc = register_filesystem(&ecryptfs_fs_type);
 867         if (rc) {
 868                 printk(KERN_ERR "Failed to register filesystem\n");
 869                 goto out_free_kmem_caches;
 870         }
 871         rc = do_sysfs_registration();
 872         if (rc) {
 873                 printk(KERN_ERR "sysfs registration failed\n");
 874                 goto out_unregister_filesystem;
 875         }
 876         rc = ecryptfs_init_kthread();
 877         if (rc) {
 878                 printk(KERN_ERR "%s: kthread initialization failed; "
 879                        "rc = [%d]\n", __func__, rc);
 880                 goto out_do_sysfs_unregistration;
 881         }
 882         rc = ecryptfs_init_messaging();
 883         if (rc) {
 884                 printk(KERN_ERR "Failure occured while attempting to "
 885                                 "initialize the communications channel to "
 886                                 "ecryptfsd\n");
 887                 goto out_destroy_kthread;
 888         }
 889         rc = ecryptfs_init_crypto();
 890         if (rc) {
 891                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
 892                        "rc = [%d]\n", rc);
 893                 goto out_release_messaging;
 894         }
 895         if (ecryptfs_verbosity > 0)
 896                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 897                         "will be written to the syslog!\n", ecryptfs_verbosity);
 898
 899         goto out;
 900 out_release_messaging:
 901         ecryptfs_release_messaging();
 902 out_destroy_kthread:
 903         ecryptfs_destroy_kthread();
 904 out_do_sysfs_unregistration:
 905         do_sysfs_unregistration();
 906 out_unregister_filesystem:
 907         unregister_filesystem(&ecryptfs_fs_type);
 908 out_free_kmem_caches:
 909         ecryptfs_free_kmem_caches();
 910 out:
 911         return rc;
 912 }
 913
 914 static void __exit ecryptfs_exit(void)
 915 {
 916         int rc;
 917
 918         rc = ecryptfs_destroy_crypto();
 919         if (rc)
 920                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 921                        "rc = [%d]\n", rc);
 922         ecryptfs_release_messaging();
 923         ecryptfs_destroy_kthread();
 924         do_sysfs_unregistration();
 925         unregister_filesystem(&ecryptfs_fs_type);
 926         ecryptfs_free_kmem_caches();
 927 }
 928
 929 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 930 MODULE_DESCRIPTION("eCryptfs");
 931
 932 MODULE_LICENSE("GPL");
 933
 934 module_init(ecryptfs_init)
 935 module_exit(ecryptfs_exit)