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_persistent_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  * persistent file struct and associates it with the eCryptfs
 108  * inode. When the eCryptfs inode is destroyed, the file is closed.
 109  *
 110  * The persistent file will be opened with read/write permissions, if
 111  * possible. Otherwise, it is opened read-only.
 112  *
 113  * This function does nothing if a lower persistent file is already
 114  * associated with the eCryptfs inode.
 115  *
 116  * Returns zero on success; non-zero otherwise
 117  */
 118 int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry)
 119 {
 120         const struct cred *cred = current_cred();
 121         struct ecryptfs_inode_info *inode_info =
 122                 ecryptfs_inode_to_private(ecryptfs_dentry->d_inode);
 123         int rc = 0;
 124
 125         if (!inode_info->lower_file) {
 126                 struct dentry *lower_dentry;
 127                 struct vfsmount *lower_mnt =
 128                         ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
 129
 130                 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 131                 rc = ecryptfs_privileged_open(&inode_info->lower_file,
 132                                               lower_dentry, lower_mnt, cred);
 133                 if (rc) {
 134                         printk(KERN_ERR "Error opening lower persistent file "
 135                                "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
 136                                "rc = [%d]\n", lower_dentry, lower_mnt, rc);
 137                         inode_info->lower_file = NULL;
 138                 }
 139         }
 140         return rc;
 141 }
 142
 143 static struct inode *ecryptfs_get_inode(struct inode *lower_inode,
 144                        struct super_block *sb)
 145 {
 146         struct inode *inode;
 147         int rc = 0;
 148
 149         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) {
 150                 rc = -EXDEV;
 151                 goto out;
 152         }
 153         if (!igrab(lower_inode)) {
 154                 rc = -ESTALE;
 155                 goto out;
 156         }
 157         inode = iget5_locked(sb, (unsigned long)lower_inode,
 158                              ecryptfs_inode_test, ecryptfs_inode_set,
 159                              lower_inode);
 160         if (!inode) {
 161                 rc = -EACCES;
 162                 iput(lower_inode);
 163                 goto out;
 164         }
 165         if (inode->i_state & I_NEW)
 166                 unlock_new_inode(inode);
 167         else
 168                 iput(lower_inode);
 169         if (S_ISLNK(lower_inode->i_mode))
 170                 inode->i_op = &ecryptfs_symlink_iops;
 171         else if (S_ISDIR(lower_inode->i_mode))
 172                 inode->i_op = &ecryptfs_dir_iops;
 173         if (S_ISDIR(lower_inode->i_mode))
 174                 inode->i_fop = &ecryptfs_dir_fops;
 175         if (special_file(lower_inode->i_mode))
 176                 init_special_inode(inode, lower_inode->i_mode,
 177                                    lower_inode->i_rdev);
 178         fsstack_copy_attr_all(inode, lower_inode);
 179         /* This size will be overwritten for real files w/ headers and
 180          * other metadata */
 181         fsstack_copy_inode_size(inode, lower_inode);
 182         return inode;
 183 out:
 184         return ERR_PTR(rc);
 185 }
 186
 187 /**
 188  * ecryptfs_interpose
 189  * @lower_dentry: Existing dentry in the lower filesystem
 190  * @dentry: ecryptfs' dentry
 191  * @sb: ecryptfs's super_block
 192  * @flags: flags to govern behavior of interpose procedure
 193  *
 194  * Interposes upper and lower dentries.
 195  *
 196  * Returns zero on success; non-zero otherwise
 197  */
 198 int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
 199                        struct super_block *sb, u32 flags)
 200 {
 201         struct inode *lower_inode = lower_dentry->d_inode;
 202         struct inode *inode = ecryptfs_get_inode(lower_inode, sb);
 203         if (IS_ERR(inode))
 204                 return PTR_ERR(inode);
 205         if (flags & ECRYPTFS_INTERPOSE_FLAG_D_ADD)
 206                 d_add(dentry, inode);
 207         else
 208                 d_instantiate(dentry, inode);
 209         return 0;
 210 }
 211
 212 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
 213        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
 214        ecryptfs_opt_ecryptfs_key_bytes,
 215        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
 216        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
 217        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
 218        ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
 219        ecryptfs_opt_err };
 220
 221 static const match_table_t tokens = {
 222         {ecryptfs_opt_sig, "sig=%s"},
 223         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 224         {ecryptfs_opt_cipher, "cipher=%s"},
 225         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
 226         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
 227         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
 228         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
 229         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
 230         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
 231         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
 232         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
 233         {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
 234         {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
 235         {ecryptfs_opt_err, NULL}
 236 };
 237
 238 static int ecryptfs_init_global_auth_toks(
 239         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 240 {
 241         struct ecryptfs_global_auth_tok *global_auth_tok;
 242         int rc = 0;
 243
 244         list_for_each_entry(global_auth_tok,
 245                             &mount_crypt_stat->global_auth_tok_list,
 246                             mount_crypt_stat_list) {
 247                 rc = ecryptfs_keyring_auth_tok_for_sig(
 248                         &global_auth_tok->global_auth_tok_key,
 249                         &global_auth_tok->global_auth_tok,
 250                         global_auth_tok->sig);
 251                 if (rc) {
 252                         printk(KERN_ERR "Could not find valid key in user "
 253                                "session keyring for sig specified in mount "
 254                                "option: [%s]\n", global_auth_tok->sig);
 255                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 256                         goto out;
 257                 } else
 258                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
 259         }
 260 out:
 261         return rc;
 262 }
 263
 264 static void ecryptfs_init_mount_crypt_stat(
 265         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 266 {
 267         memset((void *)mount_crypt_stat, 0,
 268                sizeof(struct ecryptfs_mount_crypt_stat));
 269         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
 270         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
 271         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
 272 }
 273
 274 /**
 275  * ecryptfs_parse_options
 276  * @sb: The ecryptfs super block
 277  * @options: The options pased to the kernel
 278  *
 279  * Parse mount options:
 280  * debug=N         - ecryptfs_verbosity level for debug output
 281  * sig=XXX         - description(signature) of the key to use
 282  *
 283  * Returns the dentry object of the lower-level (lower/interposed)
 284  * directory; We want to mount our stackable file system on top of
 285  * that lower directory.
 286  *
 287  * The signature of the key to use must be the description of a key
 288  * already in the keyring. Mounting will fail if the key can not be
 289  * found.
 290  *
 291  * Returns zero on success; non-zero on error
 292  */
 293 static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options)
 294 {
 295         char *p;
 296         int rc = 0;
 297         int sig_set = 0;
 298         int cipher_name_set = 0;
 299         int fn_cipher_name_set = 0;
 300         int cipher_key_bytes;
 301         int cipher_key_bytes_set = 0;
 302         int fn_cipher_key_bytes;
 303         int fn_cipher_key_bytes_set = 0;
 304         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 305                 &sbi->mount_crypt_stat;
 306         substring_t args[MAX_OPT_ARGS];
 307         int token;
 308         char *sig_src;
 309         char *cipher_name_dst;
 310         char *cipher_name_src;
 311         char *fn_cipher_name_dst;
 312         char *fn_cipher_name_src;
 313         char *fnek_dst;
 314         char *fnek_src;
 315         char *cipher_key_bytes_src;
 316         char *fn_cipher_key_bytes_src;
 317
 318         if (!options) {
 319                 rc = -EINVAL;
 320                 goto out;
 321         }
 322         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
 323         while ((p = strsep(&options, ",")) != NULL) {
 324                 if (!*p)
 325                         continue;
 326                 token = match_token(p, tokens, args);
 327                 switch (token) {
 328                 case ecryptfs_opt_sig:
 329                 case ecryptfs_opt_ecryptfs_sig:
 330                         sig_src = args[0].from;
 331                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
 332                                                           sig_src, 0);
 333                         if (rc) {
 334                                 printk(KERN_ERR "Error attempting to register "
 335                                        "global sig; rc = [%d]\n", rc);
 336                                 goto out;
 337                         }
 338                         sig_set = 1;
 339                         break;
 340                 case ecryptfs_opt_cipher:
 341                 case ecryptfs_opt_ecryptfs_cipher:
 342                         cipher_name_src = args[0].from;
 343                         cipher_name_dst =
 344                                 mount_crypt_stat->
 345                                 global_default_cipher_name;
 346                         strncpy(cipher_name_dst, cipher_name_src,
 347                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 348                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 349                         cipher_name_set = 1;
 350                         break;
 351                 case ecryptfs_opt_ecryptfs_key_bytes:
 352                         cipher_key_bytes_src = args[0].from;
 353                         cipher_key_bytes =
 354                                 (int)simple_strtol(cipher_key_bytes_src,
 355                                                    &cipher_key_bytes_src, 0);
 356                         mount_crypt_stat->global_default_cipher_key_size =
 357                                 cipher_key_bytes;
 358                         cipher_key_bytes_set = 1;
 359                         break;
 360                 case ecryptfs_opt_passthrough:
 361                         mount_crypt_stat->flags |=
 362                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 363                         break;
 364                 case ecryptfs_opt_xattr_metadata:
 365                         mount_crypt_stat->flags |=
 366                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 367                         break;
 368                 case ecryptfs_opt_encrypted_view:
 369                         mount_crypt_stat->flags |=
 370                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 371                         mount_crypt_stat->flags |=
 372                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 373                         break;
 374                 case ecryptfs_opt_fnek_sig:
 375                         fnek_src = args[0].from;
 376                         fnek_dst =
 377                                 mount_crypt_stat->global_default_fnek_sig;
 378                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
 379                         mount_crypt_stat->global_default_fnek_sig[
 380                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
 381                         rc = ecryptfs_add_global_auth_tok(
 382                                 mount_crypt_stat,
 383                                 mount_crypt_stat->global_default_fnek_sig,
 384                                 ECRYPTFS_AUTH_TOK_FNEK);
 385                         if (rc) {
 386                                 printk(KERN_ERR "Error attempting to register "
 387                                        "global fnek sig [%s]; rc = [%d]\n",
 388                                        mount_crypt_stat->global_default_fnek_sig,
 389                                        rc);
 390                                 goto out;
 391                         }
 392                         mount_crypt_stat->flags |=
 393                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 394                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 395                         break;
 396                 case ecryptfs_opt_fn_cipher:
 397                         fn_cipher_name_src = args[0].from;
 398                         fn_cipher_name_dst =
 399                                 mount_crypt_stat->global_default_fn_cipher_name;
 400                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
 401                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 402                         mount_crypt_stat->global_default_fn_cipher_name[
 403                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 404                         fn_cipher_name_set = 1;
 405                         break;
 406                 case ecryptfs_opt_fn_cipher_key_bytes:
 407                         fn_cipher_key_bytes_src = args[0].from;
 408                         fn_cipher_key_bytes =
 409                                 (int)simple_strtol(fn_cipher_key_bytes_src,
 410                                                    &fn_cipher_key_bytes_src, 0);
 411                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
 412                                 fn_cipher_key_bytes;
 413                         fn_cipher_key_bytes_set = 1;
 414                         break;
 415                 case ecryptfs_opt_unlink_sigs:
 416                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
 417                         break;
 418                 case ecryptfs_opt_mount_auth_tok_only:
 419                         mount_crypt_stat->flags |=
 420                                 ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
 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_get_sb
 503  * @fs_type
 504  * @flags
 505  * @dev_name: The path to mount over
 506  * @raw_data: The options passed into the kernel
 507  */
 508 static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
 509                         const char *dev_name, void *raw_data)
 510 {
 511         struct super_block *s;
 512         struct ecryptfs_sb_info *sbi;
 513         struct ecryptfs_dentry_info *root_info;
 514         const char *err = "Getting sb failed";
 515         struct inode *inode;
 516         struct path path;
 517         int rc;
 518
 519         sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
 520         if (!sbi) {
 521                 rc = -ENOMEM;
 522                 goto out;
 523         }
 524
 525         rc = ecryptfs_parse_options(sbi, raw_data);
 526         if (rc) {
 527                 err = "Error parsing options";
 528                 goto out;
 529         }
 530
 531         s = sget(fs_type, NULL, set_anon_super, NULL);
 532         if (IS_ERR(s)) {
 533                 rc = PTR_ERR(s);
 534                 goto out;
 535         }
 536
 537         s->s_flags = flags;
 538         rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY);
 539         if (rc)
 540                 goto out1;
 541
 542         ecryptfs_set_superblock_private(s, sbi);
 543         s->s_bdi = &sbi->bdi;
 544
 545         /* ->kill_sb() will take care of sbi after that point */
 546         sbi = NULL;
 547         s->s_op = &ecryptfs_sops;
 548         s->s_d_op = &ecryptfs_dops;
 549
 550         err = "Reading sb failed";
 551         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 552         if (rc) {
 553                 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
 554                 goto out1;
 555         }
 556         if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
 557                 rc = -EINVAL;
 558                 printk(KERN_ERR "Mount on filesystem of type "
 559                         "eCryptfs explicitly disallowed due to "
 560                         "known incompatibilities\n");
 561                 goto out_free;
 562         }
 563         ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
 564         s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 565         s->s_blocksize = path.dentry->d_sb->s_blocksize;
 566         s->s_magic = ECRYPTFS_SUPER_MAGIC;
 567
 568         inode = ecryptfs_get_inode(path.dentry->d_inode, s);
 569         rc = PTR_ERR(inode);
 570         if (IS_ERR(inode))
 571                 goto out_free;
 572
 573         s->s_root = d_alloc_root(inode);
 574         if (!s->s_root) {
 575                 iput(inode);
 576                 rc = -ENOMEM;
 577                 goto out_free;
 578         }
 579
 580         rc = -ENOMEM;
 581         root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 582         if (!root_info)
 583                 goto out_free;
 584
 585         /* ->kill_sb() will take care of root_info */
 586         ecryptfs_set_dentry_private(s->s_root, root_info);
 587         ecryptfs_set_dentry_lower(s->s_root, path.dentry);
 588         ecryptfs_set_dentry_lower_mnt(s->s_root, path.mnt);
 589
 590         s->s_flags |= MS_ACTIVE;
 591         return dget(s->s_root);
 592
 593 out_free:
 594         path_put(&path);
 595 out1:
 596         deactivate_locked_super(s);
 597 out:
 598         if (sbi) {
 599                 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
 600                 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
 601         }
 602         printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
 603         return ERR_PTR(rc);
 604 }
 605
 606 /**
 607  * ecryptfs_kill_block_super
 608  * @sb: The ecryptfs super block
 609  *
 610  * Used to bring the superblock down and free the private data.
 611  */
 612 static void ecryptfs_kill_block_super(struct super_block *sb)
 613 {
 614         struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
 615         kill_anon_super(sb);
 616         if (!sb_info)
 617                 return;
 618         ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
 619         bdi_destroy(&sb_info->bdi);
 620         kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
 621 }
 622
 623 static struct file_system_type ecryptfs_fs_type = {
 624         .owner = THIS_MODULE,
 625         .name = "ecryptfs",
 626         .mount = ecryptfs_mount,
 627         .kill_sb = ecryptfs_kill_block_super,
 628         .fs_flags = 0
 629 };
 630
 631 /**
 632  * inode_info_init_once
 633  *
 634  * Initializes the ecryptfs_inode_info_cache when it is created
 635  */
 636 static void
 637 inode_info_init_once(void *vptr)
 638 {
 639         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 640
 641         inode_init_once(&ei->vfs_inode);
 642 }
 643
 644 static struct ecryptfs_cache_info {
 645         struct kmem_cache **cache;
 646         const char *name;
 647         size_t size;
 648         void (*ctor)(void *obj);
 649 } ecryptfs_cache_infos[] = {
 650         {
 651                 .cache = &ecryptfs_auth_tok_list_item_cache,
 652                 .name = "ecryptfs_auth_tok_list_item",
 653                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 654         },
 655         {
 656                 .cache = &ecryptfs_file_info_cache,
 657                 .name = "ecryptfs_file_cache",
 658                 .size = sizeof(struct ecryptfs_file_info),
 659         },
 660         {
 661                 .cache = &ecryptfs_dentry_info_cache,
 662                 .name = "ecryptfs_dentry_info_cache",
 663                 .size = sizeof(struct ecryptfs_dentry_info),
 664         },
 665         {
 666                 .cache = &ecryptfs_inode_info_cache,
 667                 .name = "ecryptfs_inode_cache",
 668                 .size = sizeof(struct ecryptfs_inode_info),
 669                 .ctor = inode_info_init_once,
 670         },
 671         {
 672                 .cache = &ecryptfs_sb_info_cache,
 673                 .name = "ecryptfs_sb_cache",
 674                 .size = sizeof(struct ecryptfs_sb_info),
 675         },
 676         {
 677                 .cache = &ecryptfs_header_cache_1,
 678                 .name = "ecryptfs_headers_1",
 679                 .size = PAGE_CACHE_SIZE,
 680         },
 681         {
 682                 .cache = &ecryptfs_header_cache_2,
 683                 .name = "ecryptfs_headers_2",
 684                 .size = PAGE_CACHE_SIZE,
 685         },
 686         {
 687                 .cache = &ecryptfs_xattr_cache,
 688                 .name = "ecryptfs_xattr_cache",
 689                 .size = PAGE_CACHE_SIZE,
 690         },
 691         {
 692                 .cache = &ecryptfs_key_record_cache,
 693                 .name = "ecryptfs_key_record_cache",
 694                 .size = sizeof(struct ecryptfs_key_record),
 695         },
 696         {
 697                 .cache = &ecryptfs_key_sig_cache,
 698                 .name = "ecryptfs_key_sig_cache",
 699                 .size = sizeof(struct ecryptfs_key_sig),
 700         },
 701         {
 702                 .cache = &ecryptfs_global_auth_tok_cache,
 703                 .name = "ecryptfs_global_auth_tok_cache",
 704                 .size = sizeof(struct ecryptfs_global_auth_tok),
 705         },
 706         {
 707                 .cache = &ecryptfs_key_tfm_cache,
 708                 .name = "ecryptfs_key_tfm_cache",
 709                 .size = sizeof(struct ecryptfs_key_tfm),
 710         },
 711         {
 712                 .cache = &ecryptfs_open_req_cache,
 713                 .name = "ecryptfs_open_req_cache",
 714                 .size = sizeof(struct ecryptfs_open_req),
 715         },
 716 };
 717
 718 static void ecryptfs_free_kmem_caches(void)
 719 {
 720         int i;
 721
 722         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 723                 struct ecryptfs_cache_info *info;
 724
 725                 info = &ecryptfs_cache_infos[i];
 726                 if (*(info->cache))
 727                         kmem_cache_destroy(*(info->cache));
 728         }
 729 }
 730
 731 /**
 732  * ecryptfs_init_kmem_caches
 733  *
 734  * Returns zero on success; non-zero otherwise
 735  */
 736 static int ecryptfs_init_kmem_caches(void)
 737 {
 738         int i;
 739
 740         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 741                 struct ecryptfs_cache_info *info;
 742
 743                 info = &ecryptfs_cache_infos[i];
 744                 *(info->cache) = kmem_cache_create(info->name, info->size,
 745                                 0, SLAB_HWCACHE_ALIGN, info->ctor);
 746                 if (!*(info->cache)) {
 747                         ecryptfs_free_kmem_caches();
 748                         ecryptfs_printk(KERN_WARNING, "%s: "
 749                                         "kmem_cache_create failed\n",
 750                                         info->name);
 751                         return -ENOMEM;
 752                 }
 753         }
 754         return 0;
 755 }
 756
 757 static struct kobject *ecryptfs_kobj;
 758
 759 static ssize_t version_show(struct kobject *kobj,
 760                             struct kobj_attribute *attr, char *buff)
 761 {
 762         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 763 }
 764
 765 static struct kobj_attribute version_attr = __ATTR_RO(version);
 766
 767 static struct attribute *attributes[] = {
 768         &version_attr.attr,
 769         NULL,
 770 };
 771
 772 static struct attribute_group attr_group = {
 773         .attrs = attributes,
 774 };
 775
 776 static int do_sysfs_registration(void)
 777 {
 778         int rc;
 779
 780         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 781         if (!ecryptfs_kobj) {
 782                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
 783                 rc = -ENOMEM;
 784                 goto out;
 785         }
 786         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 787         if (rc) {
 788                 printk(KERN_ERR
 789                        "Unable to create ecryptfs version attributes\n");
 790                 kobject_put(ecryptfs_kobj);
 791         }
 792 out:
 793         return rc;
 794 }
 795
 796 static void do_sysfs_unregistration(void)
 797 {
 798         sysfs_remove_group(ecryptfs_kobj, &attr_group);
 799         kobject_put(ecryptfs_kobj);
 800 }
 801
 802 static int __init ecryptfs_init(void)
 803 {
 804         int rc;
 805
 806         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
 807                 rc = -EINVAL;
 808                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 809                                 "larger than the host's page size, and so "
 810                                 "eCryptfs cannot run on this system. The "
 811                                 "default eCryptfs extent size is [%u] bytes; "
 812                                 "the page size is [%lu] bytes.\n",
 813                                 ECRYPTFS_DEFAULT_EXTENT_SIZE,
 814                                 (unsigned long)PAGE_CACHE_SIZE);
 815                 goto out;
 816         }
 817         rc = ecryptfs_init_kmem_caches();
 818         if (rc) {
 819                 printk(KERN_ERR
 820                        "Failed to allocate one or more kmem_cache objects\n");
 821                 goto out;
 822         }
 823         rc = register_filesystem(&ecryptfs_fs_type);
 824         if (rc) {
 825                 printk(KERN_ERR "Failed to register filesystem\n");
 826                 goto out_free_kmem_caches;
 827         }
 828         rc = do_sysfs_registration();
 829         if (rc) {
 830                 printk(KERN_ERR "sysfs registration failed\n");
 831                 goto out_unregister_filesystem;
 832         }
 833         rc = ecryptfs_init_kthread();
 834         if (rc) {
 835                 printk(KERN_ERR "%s: kthread initialization failed; "
 836                        "rc = [%d]\n", __func__, rc);
 837                 goto out_do_sysfs_unregistration;
 838         }
 839         rc = ecryptfs_init_messaging();
 840         if (rc) {
 841                 printk(KERN_ERR "Failure occured while attempting to "
 842                                 "initialize the communications channel to "
 843                                 "ecryptfsd\n");
 844                 goto out_destroy_kthread;
 845         }
 846         rc = ecryptfs_init_crypto();
 847         if (rc) {
 848                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
 849                        "rc = [%d]\n", rc);
 850                 goto out_release_messaging;
 851         }
 852         if (ecryptfs_verbosity > 0)
 853                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 854                         "will be written to the syslog!\n", ecryptfs_verbosity);
 855
 856         goto out;
 857 out_release_messaging:
 858         ecryptfs_release_messaging();
 859 out_destroy_kthread:
 860         ecryptfs_destroy_kthread();
 861 out_do_sysfs_unregistration:
 862         do_sysfs_unregistration();
 863 out_unregister_filesystem:
 864         unregister_filesystem(&ecryptfs_fs_type);
 865 out_free_kmem_caches:
 866         ecryptfs_free_kmem_caches();
 867 out:
 868         return rc;
 869 }
 870
 871 static void __exit ecryptfs_exit(void)
 872 {
 873         int rc;
 874
 875         rc = ecryptfs_destroy_crypto();
 876         if (rc)
 877                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 878                        "rc = [%d]\n", rc);
 879         ecryptfs_release_messaging();
 880         ecryptfs_destroy_kthread();
 881         do_sysfs_unregistration();
 882         unregister_filesystem(&ecryptfs_fs_type);
 883         ecryptfs_free_kmem_caches();
 884 }
 885
 886 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 887 MODULE_DESCRIPTION("eCryptfs");
 888
 889 MODULE_LICENSE("GPL");
 890
 891 module_init(ecryptfs_init)
 892 module_exit(ecryptfs_exit)