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_err };
 216
 217 static const match_table_t tokens = {
 218         {ecryptfs_opt_sig, "sig=%s"},
 219         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 220         {ecryptfs_opt_cipher, "cipher=%s"},
 221         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
 222         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
 223         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
 224         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
 225         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
 226         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
 227         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
 228         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
 229         {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
 230         {ecryptfs_opt_err, NULL}
 231 };
 232
 233 static int ecryptfs_init_global_auth_toks(
 234         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 235 {
 236         struct ecryptfs_global_auth_tok *global_auth_tok;
 237         int rc = 0;
 238
 239         list_for_each_entry(global_auth_tok,
 240                             &mount_crypt_stat->global_auth_tok_list,
 241                             mount_crypt_stat_list) {
 242                 rc = ecryptfs_keyring_auth_tok_for_sig(
 243                         &global_auth_tok->global_auth_tok_key,
 244                         &global_auth_tok->global_auth_tok,
 245                         global_auth_tok->sig);
 246                 if (rc) {
 247                         printk(KERN_ERR "Could not find valid key in user "
 248                                "session keyring for sig specified in mount "
 249                                "option: [%s]\n", global_auth_tok->sig);
 250                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 251                         goto out;
 252                 } else
 253                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
 254         }
 255 out:
 256         return rc;
 257 }
 258
 259 static void ecryptfs_init_mount_crypt_stat(
 260         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 261 {
 262         memset((void *)mount_crypt_stat, 0,
 263                sizeof(struct ecryptfs_mount_crypt_stat));
 264         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
 265         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
 266         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
 267 }
 268
 269 /**
 270  * ecryptfs_parse_options
 271  * @sb: The ecryptfs super block
 272  * @options: The options pased to the kernel
 273  *
 274  * Parse mount options:
 275  * debug=N         - ecryptfs_verbosity level for debug output
 276  * sig=XXX         - description(signature) of the key to use
 277  *
 278  * Returns the dentry object of the lower-level (lower/interposed)
 279  * directory; We want to mount our stackable file system on top of
 280  * that lower directory.
 281  *
 282  * The signature of the key to use must be the description of a key
 283  * already in the keyring. Mounting will fail if the key can not be
 284  * found.
 285  *
 286  * Returns zero on success; non-zero on error
 287  */
 288 static int ecryptfs_parse_options(struct super_block *sb, char *options)
 289 {
 290         char *p;
 291         int rc = 0;
 292         int sig_set = 0;
 293         int cipher_name_set = 0;
 294         int fn_cipher_name_set = 0;
 295         int cipher_key_bytes;
 296         int cipher_key_bytes_set = 0;
 297         int fn_cipher_key_bytes;
 298         int fn_cipher_key_bytes_set = 0;
 299         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 300                 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
 301         substring_t args[MAX_OPT_ARGS];
 302         int token;
 303         char *sig_src;
 304         char *cipher_name_dst;
 305         char *cipher_name_src;
 306         char *fn_cipher_name_dst;
 307         char *fn_cipher_name_src;
 308         char *fnek_dst;
 309         char *fnek_src;
 310         char *cipher_key_bytes_src;
 311         char *fn_cipher_key_bytes_src;
 312
 313         if (!options) {
 314                 rc = -EINVAL;
 315                 goto out;
 316         }
 317         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
 318         while ((p = strsep(&options, ",")) != NULL) {
 319                 if (!*p)
 320                         continue;
 321                 token = match_token(p, tokens, args);
 322                 switch (token) {
 323                 case ecryptfs_opt_sig:
 324                 case ecryptfs_opt_ecryptfs_sig:
 325                         sig_src = args[0].from;
 326                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
 327                                                           sig_src, 0);
 328                         if (rc) {
 329                                 printk(KERN_ERR "Error attempting to register "
 330                                        "global sig; rc = [%d]\n", rc);
 331                                 goto out;
 332                         }
 333                         sig_set = 1;
 334                         break;
 335                 case ecryptfs_opt_cipher:
 336                 case ecryptfs_opt_ecryptfs_cipher:
 337                         cipher_name_src = args[0].from;
 338                         cipher_name_dst =
 339                                 mount_crypt_stat->
 340                                 global_default_cipher_name;
 341                         strncpy(cipher_name_dst, cipher_name_src,
 342                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 343                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 344                         cipher_name_set = 1;
 345                         break;
 346                 case ecryptfs_opt_ecryptfs_key_bytes:
 347                         cipher_key_bytes_src = args[0].from;
 348                         cipher_key_bytes =
 349                                 (int)simple_strtol(cipher_key_bytes_src,
 350                                                    &cipher_key_bytes_src, 0);
 351                         mount_crypt_stat->global_default_cipher_key_size =
 352                                 cipher_key_bytes;
 353                         cipher_key_bytes_set = 1;
 354                         break;
 355                 case ecryptfs_opt_passthrough:
 356                         mount_crypt_stat->flags |=
 357                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 358                         break;
 359                 case ecryptfs_opt_xattr_metadata:
 360                         mount_crypt_stat->flags |=
 361                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 362                         break;
 363                 case ecryptfs_opt_encrypted_view:
 364                         mount_crypt_stat->flags |=
 365                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 366                         mount_crypt_stat->flags |=
 367                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 368                         break;
 369                 case ecryptfs_opt_fnek_sig:
 370                         fnek_src = args[0].from;
 371                         fnek_dst =
 372                                 mount_crypt_stat->global_default_fnek_sig;
 373                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
 374                         mount_crypt_stat->global_default_fnek_sig[
 375                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
 376                         rc = ecryptfs_add_global_auth_tok(
 377                                 mount_crypt_stat,
 378                                 mount_crypt_stat->global_default_fnek_sig,
 379                                 ECRYPTFS_AUTH_TOK_FNEK);
 380                         if (rc) {
 381                                 printk(KERN_ERR "Error attempting to register "
 382                                        "global fnek sig [%s]; rc = [%d]\n",
 383                                        mount_crypt_stat->global_default_fnek_sig,
 384                                        rc);
 385                                 goto out;
 386                         }
 387                         mount_crypt_stat->flags |=
 388                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 389                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 390                         break;
 391                 case ecryptfs_opt_fn_cipher:
 392                         fn_cipher_name_src = args[0].from;
 393                         fn_cipher_name_dst =
 394                                 mount_crypt_stat->global_default_fn_cipher_name;
 395                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
 396                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 397                         mount_crypt_stat->global_default_fn_cipher_name[
 398                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 399                         fn_cipher_name_set = 1;
 400                         break;
 401                 case ecryptfs_opt_fn_cipher_key_bytes:
 402                         fn_cipher_key_bytes_src = args[0].from;
 403                         fn_cipher_key_bytes =
 404                                 (int)simple_strtol(fn_cipher_key_bytes_src,
 405                                                    &fn_cipher_key_bytes_src, 0);
 406                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
 407                                 fn_cipher_key_bytes;
 408                         fn_cipher_key_bytes_set = 1;
 409                         break;
 410                 case ecryptfs_opt_unlink_sigs:
 411                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
 412                         break;
 413                 case ecryptfs_opt_err:
 414                 default:
 415                         printk(KERN_WARNING
 416                                "%s: eCryptfs: unrecognized option [%s]\n",
 417                                __func__, p);
 418                 }
 419         }
 420         if (!sig_set) {
 421                 rc = -EINVAL;
 422                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
 423                                 "auth tok signature as a mount "
 424                                 "parameter; see the eCryptfs README\n");
 425                 goto out;
 426         }
 427         if (!cipher_name_set) {
 428                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 429
 430                 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 431                 strcpy(mount_crypt_stat->global_default_cipher_name,
 432                        ECRYPTFS_DEFAULT_CIPHER);
 433         }
 434         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 435             && !fn_cipher_name_set)
 436                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
 437                        mount_crypt_stat->global_default_cipher_name);
 438         if (!cipher_key_bytes_set)
 439                 mount_crypt_stat->global_default_cipher_key_size = 0;
 440         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 441             && !fn_cipher_key_bytes_set)
 442                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
 443                         mount_crypt_stat->global_default_cipher_key_size;
 444         mutex_lock(&key_tfm_list_mutex);
 445         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
 446                                  NULL)) {
 447                 rc = ecryptfs_add_new_key_tfm(
 448                         NULL, mount_crypt_stat->global_default_cipher_name,
 449                         mount_crypt_stat->global_default_cipher_key_size);
 450                 if (rc) {
 451                         printk(KERN_ERR "Error attempting to initialize "
 452                                "cipher with name = [%s] and key size = [%td]; "
 453                                "rc = [%d]\n",
 454                                mount_crypt_stat->global_default_cipher_name,
 455                                mount_crypt_stat->global_default_cipher_key_size,
 456                                rc);
 457                         rc = -EINVAL;
 458                         mutex_unlock(&key_tfm_list_mutex);
 459                         goto out;
 460                 }
 461         }
 462         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 463             && !ecryptfs_tfm_exists(
 464                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
 465                 rc = ecryptfs_add_new_key_tfm(
 466                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
 467                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
 468                 if (rc) {
 469                         printk(KERN_ERR "Error attempting to initialize "
 470                                "cipher with name = [%s] and key size = [%td]; "
 471                                "rc = [%d]\n",
 472                                mount_crypt_stat->global_default_fn_cipher_name,
 473                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
 474                                rc);
 475                         rc = -EINVAL;
 476                         mutex_unlock(&key_tfm_list_mutex);
 477                         goto out;
 478                 }
 479         }
 480         mutex_unlock(&key_tfm_list_mutex);
 481         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
 482         if (rc)
 483                 printk(KERN_WARNING "One or more global auth toks could not "
 484                        "properly register; rc = [%d]\n", rc);
 485 out:
 486         return rc;
 487 }
 488
 489 struct kmem_cache *ecryptfs_sb_info_cache;
 490
 491 /**
 492  * ecryptfs_fill_super
 493  * @sb: The ecryptfs super block
 494  * @raw_data: The options passed to mount
 495  * @silent: Not used but required by function prototype
 496  *
 497  * Sets up what we can of the sb, rest is done in ecryptfs_read_super
 498  *
 499  * Returns zero on success; non-zero otherwise
 500  */
 501 static int
 502 ecryptfs_fill_super(struct super_block *sb, void *raw_data, int silent)
 503 {
 504         int rc = 0;
 505
 506         /* Released in ecryptfs_put_super() */
 507         ecryptfs_set_superblock_private(sb,
 508                                         kmem_cache_zalloc(ecryptfs_sb_info_cache,
 509                                                          GFP_KERNEL));
 510         if (!ecryptfs_superblock_to_private(sb)) {
 511                 ecryptfs_printk(KERN_WARNING, "Out of memory\n");
 512                 rc = -ENOMEM;
 513                 goto out;
 514         }
 515         sb->s_op = &ecryptfs_sops;
 516         /* Released through deactivate_super(sb) from get_sb_nodev */
 517         sb->s_root = d_alloc(NULL, &(const struct qstr) {
 518                              .hash = 0,.name = "/",.len = 1});
 519         if (!sb->s_root) {
 520                 ecryptfs_printk(KERN_ERR, "d_alloc failed\n");
 521                 rc = -ENOMEM;
 522                 goto out;
 523         }
 524         sb->s_root->d_op = &ecryptfs_dops;
 525         sb->s_root->d_sb = sb;
 526         sb->s_root->d_parent = sb->s_root;
 527         /* Released in d_release when dput(sb->s_root) is called */
 528         /* through deactivate_super(sb) from get_sb_nodev() */
 529         ecryptfs_set_dentry_private(sb->s_root,
 530                                     kmem_cache_zalloc(ecryptfs_dentry_info_cache,
 531                                                      GFP_KERNEL));
 532         if (!ecryptfs_dentry_to_private(sb->s_root)) {
 533                 ecryptfs_printk(KERN_ERR,
 534                                 "dentry_info_cache alloc failed\n");
 535                 rc = -ENOMEM;
 536                 goto out;
 537         }
 538         rc = 0;
 539 out:
 540         /* Should be able to rely on deactivate_super called from
 541          * get_sb_nodev */
 542         return rc;
 543 }
 544
 545 /**
 546  * ecryptfs_read_super
 547  * @sb: The ecryptfs super block
 548  * @dev_name: The path to mount over
 549  *
 550  * Read the super block of the lower filesystem, and use
 551  * ecryptfs_interpose to create our initial inode and super block
 552  * struct.
 553  */
 554 static int ecryptfs_read_super(struct super_block *sb, const char *dev_name)
 555 {
 556         struct path path;
 557         int rc;
 558
 559         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 560         if (rc) {
 561                 ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n");
 562                 goto out;
 563         }
 564         ecryptfs_set_superblock_lower(sb, path.dentry->d_sb);
 565         sb->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 566         sb->s_blocksize = path.dentry->d_sb->s_blocksize;
 567         ecryptfs_set_dentry_lower(sb->s_root, path.dentry);
 568         ecryptfs_set_dentry_lower_mnt(sb->s_root, path.mnt);
 569         rc = ecryptfs_interpose(path.dentry, sb->s_root, sb, 0);
 570         if (rc)
 571                 goto out_free;
 572         rc = 0;
 573         goto out;
 574 out_free:
 575         path_put(&path);
 576 out:
 577         return rc;
 578 }
 579
 580 /**
 581  * ecryptfs_get_sb
 582  * @fs_type
 583  * @flags
 584  * @dev_name: The path to mount over
 585  * @raw_data: The options passed into the kernel
 586  *
 587  * The whole ecryptfs_get_sb process is broken into 4 functions:
 588  * ecryptfs_parse_options(): handle options passed to ecryptfs, if any
 589  * ecryptfs_fill_super(): used by get_sb_nodev, fills out the super_block
 590  *                        with as much information as it can before needing
 591  *                        the lower filesystem.
 592  * ecryptfs_read_super(): this accesses the lower filesystem and uses
 593  *                        ecryptfs_interpolate to perform most of the linking
 594  * ecryptfs_interpolate(): links the lower filesystem into ecryptfs
 595  */
 596 static int ecryptfs_get_sb(struct file_system_type *fs_type, int flags,
 597                         const char *dev_name, void *raw_data,
 598                         struct vfsmount *mnt)
 599 {
 600         int rc;
 601         struct super_block *sb;
 602
 603         rc = get_sb_nodev(fs_type, flags, raw_data, ecryptfs_fill_super, mnt);
 604         if (rc < 0) {
 605                 printk(KERN_ERR "Getting sb failed; rc = [%d]\n", rc);
 606                 goto out;
 607         }
 608         sb = mnt->mnt_sb;
 609         rc = ecryptfs_parse_options(sb, raw_data);
 610         if (rc) {
 611                 printk(KERN_ERR "Error parsing options; rc = [%d]\n", rc);
 612                 goto out_abort;
 613         }
 614         rc = ecryptfs_read_super(sb, dev_name);
 615         if (rc) {
 616                 printk(KERN_ERR "Reading sb failed; rc = [%d]\n", rc);
 617                 goto out_abort;
 618         }
 619         goto out;
 620 out_abort:
 621         dput(sb->s_root); /* aka mnt->mnt_root, as set by get_sb_nodev() */
 622         deactivate_locked_super(sb);
 623 out:
 624         return rc;
 625 }
 626
 627 /**
 628  * ecryptfs_kill_block_super
 629  * @sb: The ecryptfs super block
 630  *
 631  * Used to bring the superblock down and free the private data.
 632  * Private data is free'd in ecryptfs_put_super()
 633  */
 634 static void ecryptfs_kill_block_super(struct super_block *sb)
 635 {
 636         generic_shutdown_super(sb);
 637 }
 638
 639 static struct file_system_type ecryptfs_fs_type = {
 640         .owner = THIS_MODULE,
 641         .name = "ecryptfs",
 642         .get_sb = ecryptfs_get_sb,
 643         .kill_sb = ecryptfs_kill_block_super,
 644         .fs_flags = 0
 645 };
 646
 647 /**
 648  * inode_info_init_once
 649  *
 650  * Initializes the ecryptfs_inode_info_cache when it is created
 651  */
 652 static void
 653 inode_info_init_once(void *vptr)
 654 {
 655         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 656
 657         inode_init_once(&ei->vfs_inode);
 658 }
 659
 660 static struct ecryptfs_cache_info {
 661         struct kmem_cache **cache;
 662         const char *name;
 663         size_t size;
 664         void (*ctor)(void *obj);
 665 } ecryptfs_cache_infos[] = {
 666         {
 667                 .cache = &ecryptfs_auth_tok_list_item_cache,
 668                 .name = "ecryptfs_auth_tok_list_item",
 669                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 670         },
 671         {
 672                 .cache = &ecryptfs_file_info_cache,
 673                 .name = "ecryptfs_file_cache",
 674                 .size = sizeof(struct ecryptfs_file_info),
 675         },
 676         {
 677                 .cache = &ecryptfs_dentry_info_cache,
 678                 .name = "ecryptfs_dentry_info_cache",
 679                 .size = sizeof(struct ecryptfs_dentry_info),
 680         },
 681         {
 682                 .cache = &ecryptfs_inode_info_cache,
 683                 .name = "ecryptfs_inode_cache",
 684                 .size = sizeof(struct ecryptfs_inode_info),
 685                 .ctor = inode_info_init_once,
 686         },
 687         {
 688                 .cache = &ecryptfs_sb_info_cache,
 689                 .name = "ecryptfs_sb_cache",
 690                 .size = sizeof(struct ecryptfs_sb_info),
 691         },
 692         {
 693                 .cache = &ecryptfs_header_cache_1,
 694                 .name = "ecryptfs_headers_1",
 695                 .size = PAGE_CACHE_SIZE,
 696         },
 697         {
 698                 .cache = &ecryptfs_header_cache_2,
 699                 .name = "ecryptfs_headers_2",
 700                 .size = PAGE_CACHE_SIZE,
 701         },
 702         {
 703                 .cache = &ecryptfs_xattr_cache,
 704                 .name = "ecryptfs_xattr_cache",
 705                 .size = PAGE_CACHE_SIZE,
 706         },
 707         {
 708                 .cache = &ecryptfs_key_record_cache,
 709                 .name = "ecryptfs_key_record_cache",
 710                 .size = sizeof(struct ecryptfs_key_record),
 711         },
 712         {
 713                 .cache = &ecryptfs_key_sig_cache,
 714                 .name = "ecryptfs_key_sig_cache",
 715                 .size = sizeof(struct ecryptfs_key_sig),
 716         },
 717         {
 718                 .cache = &ecryptfs_global_auth_tok_cache,
 719                 .name = "ecryptfs_global_auth_tok_cache",
 720                 .size = sizeof(struct ecryptfs_global_auth_tok),
 721         },
 722         {
 723                 .cache = &ecryptfs_key_tfm_cache,
 724                 .name = "ecryptfs_key_tfm_cache",
 725                 .size = sizeof(struct ecryptfs_key_tfm),
 726         },
 727         {
 728                 .cache = &ecryptfs_open_req_cache,
 729                 .name = "ecryptfs_open_req_cache",
 730                 .size = sizeof(struct ecryptfs_open_req),
 731         },
 732 };
 733
 734 static void ecryptfs_free_kmem_caches(void)
 735 {
 736         int i;
 737
 738         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 739                 struct ecryptfs_cache_info *info;
 740
 741                 info = &ecryptfs_cache_infos[i];
 742                 if (*(info->cache))
 743                         kmem_cache_destroy(*(info->cache));
 744         }
 745 }
 746
 747 /**
 748  * ecryptfs_init_kmem_caches
 749  *
 750  * Returns zero on success; non-zero otherwise
 751  */
 752 static int ecryptfs_init_kmem_caches(void)
 753 {
 754         int i;
 755
 756         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 757                 struct ecryptfs_cache_info *info;
 758
 759                 info = &ecryptfs_cache_infos[i];
 760                 *(info->cache) = kmem_cache_create(info->name, info->size,
 761                                 0, SLAB_HWCACHE_ALIGN, info->ctor);
 762                 if (!*(info->cache)) {
 763                         ecryptfs_free_kmem_caches();
 764                         ecryptfs_printk(KERN_WARNING, "%s: "
 765                                         "kmem_cache_create failed\n",
 766                                         info->name);
 767                         return -ENOMEM;
 768                 }
 769         }
 770         return 0;
 771 }
 772
 773 static struct kobject *ecryptfs_kobj;
 774
 775 static ssize_t version_show(struct kobject *kobj,
 776                             struct kobj_attribute *attr, char *buff)
 777 {
 778         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 779 }
 780
 781 static struct kobj_attribute version_attr = __ATTR_RO(version);
 782
 783 static struct attribute *attributes[] = {
 784         &version_attr.attr,
 785         NULL,
 786 };
 787
 788 static struct attribute_group attr_group = {
 789         .attrs = attributes,
 790 };
 791
 792 static int do_sysfs_registration(void)
 793 {
 794         int rc;
 795
 796         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 797         if (!ecryptfs_kobj) {
 798                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
 799                 rc = -ENOMEM;
 800                 goto out;
 801         }
 802         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 803         if (rc) {
 804                 printk(KERN_ERR
 805                        "Unable to create ecryptfs version attributes\n");
 806                 kobject_put(ecryptfs_kobj);
 807         }
 808 out:
 809         return rc;
 810 }
 811
 812 static void do_sysfs_unregistration(void)
 813 {
 814         sysfs_remove_group(ecryptfs_kobj, &attr_group);
 815         kobject_put(ecryptfs_kobj);
 816 }
 817
 818 static int __init ecryptfs_init(void)
 819 {
 820         int rc;
 821
 822         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
 823                 rc = -EINVAL;
 824                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 825                                 "larger than the host's page size, and so "
 826                                 "eCryptfs cannot run on this system. The "
 827                                 "default eCryptfs extent size is [%d] bytes; "
 828                                 "the page size is [%d] bytes.\n",
 829                                 ECRYPTFS_DEFAULT_EXTENT_SIZE, PAGE_CACHE_SIZE);
 830                 goto out;
 831         }
 832         rc = ecryptfs_init_kmem_caches();
 833         if (rc) {
 834                 printk(KERN_ERR
 835                        "Failed to allocate one or more kmem_cache objects\n");
 836                 goto out;
 837         }
 838         rc = register_filesystem(&ecryptfs_fs_type);
 839         if (rc) {
 840                 printk(KERN_ERR "Failed to register filesystem\n");
 841                 goto out_free_kmem_caches;
 842         }
 843         rc = do_sysfs_registration();
 844         if (rc) {
 845                 printk(KERN_ERR "sysfs registration failed\n");
 846                 goto out_unregister_filesystem;
 847         }
 848         rc = ecryptfs_init_kthread();
 849         if (rc) {
 850                 printk(KERN_ERR "%s: kthread initialization failed; "
 851                        "rc = [%d]\n", __func__, rc);
 852                 goto out_do_sysfs_unregistration;
 853         }
 854         rc = ecryptfs_init_messaging();
 855         if (rc) {
 856                 printk(KERN_ERR "Failure occured while attempting to "
 857                                 "initialize the communications channel to "
 858                                 "ecryptfsd\n");
 859                 goto out_destroy_kthread;
 860         }
 861         rc = ecryptfs_init_crypto();
 862         if (rc) {
 863                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
 864                        "rc = [%d]\n", rc);
 865                 goto out_release_messaging;
 866         }
 867         if (ecryptfs_verbosity > 0)
 868                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 869                         "will be written to the syslog!\n", ecryptfs_verbosity);
 870
 871         goto out;
 872 out_release_messaging:
 873         ecryptfs_release_messaging();
 874 out_destroy_kthread:
 875         ecryptfs_destroy_kthread();
 876 out_do_sysfs_unregistration:
 877         do_sysfs_unregistration();
 878 out_unregister_filesystem:
 879         unregister_filesystem(&ecryptfs_fs_type);
 880 out_free_kmem_caches:
 881         ecryptfs_free_kmem_caches();
 882 out:
 883         return rc;
 884 }
 885
 886 static void __exit ecryptfs_exit(void)
 887 {
 888         int rc;
 889
 890         rc = ecryptfs_destroy_crypto();
 891         if (rc)
 892                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 893                        "rc = [%d]\n", rc);
 894         ecryptfs_release_messaging();
 895         ecryptfs_destroy_kthread();
 896         do_sysfs_unregistration();
 897         unregister_filesystem(&ecryptfs_fs_type);
 898         ecryptfs_free_kmem_caches();
 899 }
 900
 901 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 902 MODULE_DESCRIPTION("eCryptfs");
 903
 904 MODULE_LICENSE("GPL");
 905
 906 module_init(ecryptfs_init)
 907 module_exit(ecryptfs_exit)