fs/ecryptfs/main.c

   1 /**
   2  * eCryptfs: Linux filesystem encryption layer
   3  *
   4  * Copyright (C) 1997-2003 Erez Zadok
   5  * Copyright (C) 2001-2003 Stony Brook University
   6  * Copyright (C) 2004-2007 International Business Machines Corp.
   7  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
   8  *              Michael C. Thompson <mcthomps@us.ibm.com>
   9  *              Tyler Hicks <tyhicks@ou.edu>
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License as
  13  * published by the Free Software Foundation; either version 2 of the
  14  * License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful, but
  17  * WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19  * General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  24  * 02111-1307, USA.
  25  */
  26
  27 #include <linux/dcache.h>
  28 #include <linux/file.h>
  29 #include <linux/module.h>
  30 #include <linux/namei.h>
  31 #include <linux/skbuff.h>
  32 #include <linux/crypto.h>
  33 #include <linux/mount.h>
  34 #include <linux/pagemap.h>
  35 #include <linux/key.h>
  36 #include <linux/parser.h>
  37 #include <linux/fs_stack.h>
  38 #include <linux/slab.h>
  39 #include <linux/magic.h>
  40 #include "ecryptfs_kernel.h"
  41
  42 /**
  43  * Module parameter that defines the ecryptfs_verbosity level.
  44  */
  45 int ecryptfs_verbosity = 0;
  46
  47 module_param(ecryptfs_verbosity, int, 0);
  48 MODULE_PARM_DESC(ecryptfs_verbosity,
  49                  "Initial verbosity level (0 or 1; defaults to "
  50                  "0, which is Quiet)");
  51
  52 /**
  53  * Module parameter that defines the number of message buffer elements
  54  */
  55 unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
  56
  57 module_param(ecryptfs_message_buf_len, uint, 0);
  58 MODULE_PARM_DESC(ecryptfs_message_buf_len,
  59                  "Number of message buffer elements");
  60
  61 /**
  62  * Module parameter that defines the maximum guaranteed amount of time to wait
  63  * for a response from ecryptfsd.  The actual sleep time will be, more than
  64  * likely, a small amount greater than this specified value, but only less if
  65  * the message successfully arrives.
  66  */
  67 signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
  68
  69 module_param(ecryptfs_message_wait_timeout, long, 0);
  70 MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
  71                  "Maximum number of seconds that an operation will "
  72                  "sleep while waiting for a message response from "
  73                  "userspace");
  74
  75 /**
  76  * Module parameter that is an estimate of the maximum number of users
  77  * that will be concurrently using eCryptfs. Set this to the right
  78  * value to balance performance and memory use.
  79  */
  80 unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
  81
  82 module_param(ecryptfs_number_of_users, uint, 0);
  83 MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
  84                  "concurrent users of eCryptfs");
  85
  86 void __ecryptfs_printk(const char *fmt, ...)
  87 {
  88         va_list args;
  89         va_start(args, fmt);
  90         if (fmt[1] == '7') { /* KERN_DEBUG */
  91                 if (ecryptfs_verbosity >= 1)
  92                         vprintk(fmt, args);
  93         } else
  94                 vprintk(fmt, args);
  95         va_end(args);
  96 }
  97
  98 /**
  99  * ecryptfs_init_lower_file
 100  * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
 101  *                   the lower dentry and the lower mount set
 102  *
 103  * eCryptfs only ever keeps a single open file for every lower
 104  * inode. All I/O operations to the lower inode occur through that
 105  * file. When the first eCryptfs dentry that interposes with the first
 106  * lower dentry for that inode is created, this function creates the
 107  * lower file struct and associates it with the eCryptfs
 108  * inode. When all eCryptfs files associated with the inode are released, the
 109  * file is closed.
 110  *
 111  * The lower file will be opened with read/write permissions, if
 112  * possible. Otherwise, it is opened read-only.
 113  *
 114  * This function does nothing if a lower file is already
 115  * associated with the eCryptfs inode.
 116  *
 117  * Returns zero on success; non-zero otherwise
 118  */
 119 static int ecryptfs_init_lower_file(struct dentry *dentry,
 120                                     struct file **lower_file)
 121 {
 122         const struct cred *cred = current_cred();
 123         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 124         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 125         int rc;
 126
 127         rc = ecryptfs_privileged_open(lower_file, lower_dentry, lower_mnt,
 128                                       cred);
 129         if (rc) {
 130                 printk(KERN_ERR "Error opening lower file "
 131                        "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
 132                        "rc = [%d]\n", lower_dentry, lower_mnt, rc);
 133                 (*lower_file) = NULL;
 134         }
 135         return rc;
 136 }
 137
 138 int ecryptfs_get_lower_file(struct dentry *dentry)
 139 {
 140         struct ecryptfs_inode_info *inode_info =
 141                 ecryptfs_inode_to_private(dentry->d_inode);
 142         int count, rc = 0;
 143
 144         mutex_lock(&inode_info->lower_file_mutex);
 145         count = atomic_inc_return(&inode_info->lower_file_count);
 146         if (WARN_ON_ONCE(count < 1))
 147                 rc = -EINVAL;
 148         else if (count == 1) {
 149                 rc = ecryptfs_init_lower_file(dentry,
 150                                               &inode_info->lower_file);
 151                 if (rc)
 152                         atomic_set(&inode_info->lower_file_count, 0);
 153         }
 154         mutex_unlock(&inode_info->lower_file_mutex);
 155         return rc;
 156 }
 157
 158 void ecryptfs_put_lower_file(struct inode *inode)
 159 {
 160         struct ecryptfs_inode_info *inode_info;
 161
 162         inode_info = ecryptfs_inode_to_private(inode);
 163         if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
 164                                       &inode_info->lower_file_mutex)) {
 165                 fput(inode_info->lower_file);
 166                 inode_info->lower_file = NULL;
 167                 mutex_unlock(&inode_info->lower_file_mutex);
 168         }
 169 }
 170
 171 static struct inode *ecryptfs_get_inode(struct inode *lower_inode,
 172                        struct super_block *sb)
 173 {
 174         struct inode *inode;
 175         int rc = 0;
 176
 177         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) {
 178                 rc = -EXDEV;
 179                 goto out;
 180         }
 181         if (!igrab(lower_inode)) {
 182                 rc = -ESTALE;
 183                 goto out;
 184         }
 185         inode = iget5_locked(sb, (unsigned long)lower_inode,
 186                              ecryptfs_inode_test, ecryptfs_inode_set,
 187                              lower_inode);
 188         if (!inode) {
 189                 rc = -EACCES;
 190                 iput(lower_inode);
 191                 goto out;
 192         }
 193         if (inode->i_state & I_NEW)
 194                 unlock_new_inode(inode);
 195         else
 196                 iput(lower_inode);
 197         if (S_ISLNK(lower_inode->i_mode))
 198                 inode->i_op = &ecryptfs_symlink_iops;
 199         else if (S_ISDIR(lower_inode->i_mode))
 200                 inode->i_op = &ecryptfs_dir_iops;
 201         if (S_ISDIR(lower_inode->i_mode))
 202                 inode->i_fop = &ecryptfs_dir_fops;
 203         if (special_file(lower_inode->i_mode))
 204                 init_special_inode(inode, lower_inode->i_mode,
 205                                    lower_inode->i_rdev);
 206         fsstack_copy_attr_all(inode, lower_inode);
 207         /* This size will be overwritten for real files w/ headers and
 208          * other metadata */
 209         fsstack_copy_inode_size(inode, lower_inode);
 210         return inode;
 211 out:
 212         return ERR_PTR(rc);
 213 }
 214
 215 /**
 216  * ecryptfs_interpose
 217  * @lower_dentry: Existing dentry in the lower filesystem
 218  * @dentry: ecryptfs' dentry
 219  * @sb: ecryptfs's super_block
 220  * @flags: flags to govern behavior of interpose procedure
 221  *
 222  * Interposes upper and lower dentries.
 223  *
 224  * Returns zero on success; non-zero otherwise
 225  */
 226 int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
 227                        struct super_block *sb, u32 flags)
 228 {
 229         struct inode *lower_inode = lower_dentry->d_inode;
 230         struct inode *inode = ecryptfs_get_inode(lower_inode, sb);
 231         if (IS_ERR(inode))
 232                 return PTR_ERR(inode);
 233         if (flags & ECRYPTFS_INTERPOSE_FLAG_D_ADD)
 234                 d_add(dentry, inode);
 235         else
 236                 d_instantiate(dentry, inode);
 237         return 0;
 238 }
 239
 240 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
 241        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
 242        ecryptfs_opt_ecryptfs_key_bytes,
 243        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
 244        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
 245        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
 246        ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
 247        ecryptfs_opt_err };
 248
 249 static const match_table_t tokens = {
 250         {ecryptfs_opt_sig, "sig=%s"},
 251         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 252         {ecryptfs_opt_cipher, "cipher=%s"},
 253         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
 254         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
 255         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
 256         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
 257         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
 258         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
 259         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
 260         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
 261         {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
 262         {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
 263         {ecryptfs_opt_err, NULL}
 264 };
 265
 266 static int ecryptfs_init_global_auth_toks(
 267         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 268 {
 269         struct ecryptfs_global_auth_tok *global_auth_tok;
 270         struct ecryptfs_auth_tok *auth_tok;
 271         int rc = 0;
 272
 273         list_for_each_entry(global_auth_tok,
 274                             &mount_crypt_stat->global_auth_tok_list,
 275                             mount_crypt_stat_list) {
 276                 rc = ecryptfs_keyring_auth_tok_for_sig(
 277                         &global_auth_tok->global_auth_tok_key, &auth_tok,
 278                         global_auth_tok->sig);
 279                 if (rc) {
 280                         printk(KERN_ERR "Could not find valid key in user "
 281                                "session keyring for sig specified in mount "
 282                                "option: [%s]\n", global_auth_tok->sig);
 283                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 284                         goto out;
 285                 } else {
 286                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
 287                         up_write(&(global_auth_tok->global_auth_tok_key)->sem);
 288                 }
 289         }
 290 out:
 291         return rc;
 292 }
 293
 294 static void ecryptfs_init_mount_crypt_stat(
 295         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 296 {
 297         memset((void *)mount_crypt_stat, 0,
 298                sizeof(struct ecryptfs_mount_crypt_stat));
 299         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
 300         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
 301         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
 302 }
 303
 304 /**
 305  * ecryptfs_parse_options
 306  * @sb: The ecryptfs super block
 307  * @options: The options passed to the kernel
 308  *
 309  * Parse mount options:
 310  * debug=N         - ecryptfs_verbosity level for debug output
 311  * sig=XXX         - description(signature) of the key to use
 312  *
 313  * Returns the dentry object of the lower-level (lower/interposed)
 314  * directory; We want to mount our stackable file system on top of
 315  * that lower directory.
 316  *
 317  * The signature of the key to use must be the description of a key
 318  * already in the keyring. Mounting will fail if the key can not be
 319  * found.
 320  *
 321  * Returns zero on success; non-zero on error
 322  */
 323 static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options)
 324 {
 325         char *p;
 326         int rc = 0;
 327         int sig_set = 0;
 328         int cipher_name_set = 0;
 329         int fn_cipher_name_set = 0;
 330         int cipher_key_bytes;
 331         int cipher_key_bytes_set = 0;
 332         int fn_cipher_key_bytes;
 333         int fn_cipher_key_bytes_set = 0;
 334         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 335                 &sbi->mount_crypt_stat;
 336         substring_t args[MAX_OPT_ARGS];
 337         int token;
 338         char *sig_src;
 339         char *cipher_name_dst;
 340         char *cipher_name_src;
 341         char *fn_cipher_name_dst;
 342         char *fn_cipher_name_src;
 343         char *fnek_dst;
 344         char *fnek_src;
 345         char *cipher_key_bytes_src;
 346         char *fn_cipher_key_bytes_src;
 347
 348         if (!options) {
 349                 rc = -EINVAL;
 350                 goto out;
 351         }
 352         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
 353         while ((p = strsep(&options, ",")) != NULL) {
 354                 if (!*p)
 355                         continue;
 356                 token = match_token(p, tokens, args);
 357                 switch (token) {
 358                 case ecryptfs_opt_sig:
 359                 case ecryptfs_opt_ecryptfs_sig:
 360                         sig_src = args[0].from;
 361                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
 362                                                           sig_src, 0);
 363                         if (rc) {
 364                                 printk(KERN_ERR "Error attempting to register "
 365                                        "global sig; rc = [%d]\n", rc);
 366                                 goto out;
 367                         }
 368                         sig_set = 1;
 369                         break;
 370                 case ecryptfs_opt_cipher:
 371                 case ecryptfs_opt_ecryptfs_cipher:
 372                         cipher_name_src = args[0].from;
 373                         cipher_name_dst =
 374                                 mount_crypt_stat->
 375                                 global_default_cipher_name;
 376                         strncpy(cipher_name_dst, cipher_name_src,
 377                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 378                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 379                         cipher_name_set = 1;
 380                         break;
 381                 case ecryptfs_opt_ecryptfs_key_bytes:
 382                         cipher_key_bytes_src = args[0].from;
 383                         cipher_key_bytes =
 384                                 (int)simple_strtol(cipher_key_bytes_src,
 385                                                    &cipher_key_bytes_src, 0);
 386                         mount_crypt_stat->global_default_cipher_key_size =
 387                                 cipher_key_bytes;
 388                         cipher_key_bytes_set = 1;
 389                         break;
 390                 case ecryptfs_opt_passthrough:
 391                         mount_crypt_stat->flags |=
 392                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 393                         break;
 394                 case ecryptfs_opt_xattr_metadata:
 395                         mount_crypt_stat->flags |=
 396                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 397                         break;
 398                 case ecryptfs_opt_encrypted_view:
 399                         mount_crypt_stat->flags |=
 400                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 401                         mount_crypt_stat->flags |=
 402                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 403                         break;
 404                 case ecryptfs_opt_fnek_sig:
 405                         fnek_src = args[0].from;
 406                         fnek_dst =
 407                                 mount_crypt_stat->global_default_fnek_sig;
 408                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
 409                         mount_crypt_stat->global_default_fnek_sig[
 410                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
 411                         rc = ecryptfs_add_global_auth_tok(
 412                                 mount_crypt_stat,
 413                                 mount_crypt_stat->global_default_fnek_sig,
 414                                 ECRYPTFS_AUTH_TOK_FNEK);
 415                         if (rc) {
 416                                 printk(KERN_ERR "Error attempting to register "
 417                                        "global fnek sig [%s]; rc = [%d]\n",
 418                                        mount_crypt_stat->global_default_fnek_sig,
 419                                        rc);
 420                                 goto out;
 421                         }
 422                         mount_crypt_stat->flags |=
 423                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 424                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 425                         break;
 426                 case ecryptfs_opt_fn_cipher:
 427                         fn_cipher_name_src = args[0].from;
 428                         fn_cipher_name_dst =
 429                                 mount_crypt_stat->global_default_fn_cipher_name;
 430                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
 431                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 432                         mount_crypt_stat->global_default_fn_cipher_name[
 433                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 434                         fn_cipher_name_set = 1;
 435                         break;
 436                 case ecryptfs_opt_fn_cipher_key_bytes:
 437                         fn_cipher_key_bytes_src = args[0].from;
 438                         fn_cipher_key_bytes =
 439                                 (int)simple_strtol(fn_cipher_key_bytes_src,
 440                                                    &fn_cipher_key_bytes_src, 0);
 441                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
 442                                 fn_cipher_key_bytes;
 443                         fn_cipher_key_bytes_set = 1;
 444                         break;
 445                 case ecryptfs_opt_unlink_sigs:
 446                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
 447                         break;
 448                 case ecryptfs_opt_mount_auth_tok_only:
 449                         mount_crypt_stat->flags |=
 450                                 ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
 451                         break;
 452                 case ecryptfs_opt_err:
 453                 default:
 454                         printk(KERN_WARNING
 455                                "%s: eCryptfs: unrecognized option [%s]\n",
 456                                __func__, p);
 457                 }
 458         }
 459         if (!sig_set) {
 460                 rc = -EINVAL;
 461                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
 462                                 "auth tok signature as a mount "
 463                                 "parameter; see the eCryptfs README\n");
 464                 goto out;
 465         }
 466         if (!cipher_name_set) {
 467                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 468
 469                 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 470                 strcpy(mount_crypt_stat->global_default_cipher_name,
 471                        ECRYPTFS_DEFAULT_CIPHER);
 472         }
 473         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 474             && !fn_cipher_name_set)
 475                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
 476                        mount_crypt_stat->global_default_cipher_name);
 477         if (!cipher_key_bytes_set)
 478                 mount_crypt_stat->global_default_cipher_key_size = 0;
 479         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 480             && !fn_cipher_key_bytes_set)
 481                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
 482                         mount_crypt_stat->global_default_cipher_key_size;
 483         mutex_lock(&key_tfm_list_mutex);
 484         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
 485                                  NULL)) {
 486                 rc = ecryptfs_add_new_key_tfm(
 487                         NULL, mount_crypt_stat->global_default_cipher_name,
 488                         mount_crypt_stat->global_default_cipher_key_size);
 489                 if (rc) {
 490                         printk(KERN_ERR "Error attempting to initialize "
 491                                "cipher with name = [%s] and key size = [%td]; "
 492                                "rc = [%d]\n",
 493                                mount_crypt_stat->global_default_cipher_name,
 494                                mount_crypt_stat->global_default_cipher_key_size,
 495                                rc);
 496                         rc = -EINVAL;
 497                         mutex_unlock(&key_tfm_list_mutex);
 498                         goto out;
 499                 }
 500         }
 501         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 502             && !ecryptfs_tfm_exists(
 503                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
 504                 rc = ecryptfs_add_new_key_tfm(
 505                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
 506                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
 507                 if (rc) {
 508                         printk(KERN_ERR "Error attempting to initialize "
 509                                "cipher with name = [%s] and key size = [%td]; "
 510                                "rc = [%d]\n",
 511                                mount_crypt_stat->global_default_fn_cipher_name,
 512                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
 513                                rc);
 514                         rc = -EINVAL;
 515                         mutex_unlock(&key_tfm_list_mutex);
 516                         goto out;
 517                 }
 518         }
 519         mutex_unlock(&key_tfm_list_mutex);
 520         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
 521         if (rc)
 522                 printk(KERN_WARNING "One or more global auth toks could not "
 523                        "properly register; rc = [%d]\n", rc);
 524 out:
 525         return rc;
 526 }
 527
 528 struct kmem_cache *ecryptfs_sb_info_cache;
 529 static struct file_system_type ecryptfs_fs_type;
 530
 531 /**
 532  * ecryptfs_get_sb
 533  * @fs_type
 534  * @flags
 535  * @dev_name: The path to mount over
 536  * @raw_data: The options passed into the kernel
 537  */
 538 static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
 539                         const char *dev_name, void *raw_data)
 540 {
 541         struct super_block *s;
 542         struct ecryptfs_sb_info *sbi;
 543         struct ecryptfs_dentry_info *root_info;
 544         const char *err = "Getting sb failed";
 545         struct inode *inode;
 546         struct path path;
 547         int rc;
 548
 549         sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
 550         if (!sbi) {
 551                 rc = -ENOMEM;
 552                 goto out;
 553         }
 554
 555         rc = ecryptfs_parse_options(sbi, raw_data);
 556         if (rc) {
 557                 err = "Error parsing options";
 558                 goto out;
 559         }
 560
 561         s = sget(fs_type, NULL, set_anon_super, NULL);
 562         if (IS_ERR(s)) {
 563                 rc = PTR_ERR(s);
 564                 goto out;
 565         }
 566
 567         s->s_flags = flags;
 568         rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY);
 569         if (rc)
 570                 goto out1;
 571
 572         ecryptfs_set_superblock_private(s, sbi);
 573         s->s_bdi = &sbi->bdi;
 574
 575         /* ->kill_sb() will take care of sbi after that point */
 576         sbi = NULL;
 577         s->s_op = &ecryptfs_sops;
 578         s->s_d_op = &ecryptfs_dops;
 579
 580         err = "Reading sb failed";
 581         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 582         if (rc) {
 583                 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
 584                 goto out1;
 585         }
 586         if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
 587                 rc = -EINVAL;
 588                 printk(KERN_ERR "Mount on filesystem of type "
 589                         "eCryptfs explicitly disallowed due to "
 590                         "known incompatibilities\n");
 591                 goto out_free;
 592         }
 593         ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
 594         s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 595         s->s_blocksize = path.dentry->d_sb->s_blocksize;
 596         s->s_magic = ECRYPTFS_SUPER_MAGIC;
 597
 598         inode = ecryptfs_get_inode(path.dentry->d_inode, s);
 599         rc = PTR_ERR(inode);
 600         if (IS_ERR(inode))
 601                 goto out_free;
 602
 603         s->s_root = d_alloc_root(inode);
 604         if (!s->s_root) {
 605                 iput(inode);
 606                 rc = -ENOMEM;
 607                 goto out_free;
 608         }
 609
 610         rc = -ENOMEM;
 611         root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 612         if (!root_info)
 613                 goto out_free;
 614
 615         /* ->kill_sb() will take care of root_info */
 616         ecryptfs_set_dentry_private(s->s_root, root_info);
 617         ecryptfs_set_dentry_lower(s->s_root, path.dentry);
 618         ecryptfs_set_dentry_lower_mnt(s->s_root, path.mnt);
 619
 620         s->s_flags |= MS_ACTIVE;
 621         return dget(s->s_root);
 622
 623 out_free:
 624         path_put(&path);
 625 out1:
 626         deactivate_locked_super(s);
 627 out:
 628         if (sbi) {
 629                 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
 630                 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
 631         }
 632         printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
 633         return ERR_PTR(rc);
 634 }
 635
 636 /**
 637  * ecryptfs_kill_block_super
 638  * @sb: The ecryptfs super block
 639  *
 640  * Used to bring the superblock down and free the private data.
 641  */
 642 static void ecryptfs_kill_block_super(struct super_block *sb)
 643 {
 644         struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
 645         kill_anon_super(sb);
 646         if (!sb_info)
 647                 return;
 648         ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
 649         bdi_destroy(&sb_info->bdi);
 650         kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
 651 }
 652
 653 static struct file_system_type ecryptfs_fs_type = {
 654         .owner = THIS_MODULE,
 655         .name = "ecryptfs",
 656         .mount = ecryptfs_mount,
 657         .kill_sb = ecryptfs_kill_block_super,
 658         .fs_flags = 0
 659 };
 660
 661 /**
 662  * inode_info_init_once
 663  *
 664  * Initializes the ecryptfs_inode_info_cache when it is created
 665  */
 666 static void
 667 inode_info_init_once(void *vptr)
 668 {
 669         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 670
 671         inode_init_once(&ei->vfs_inode);
 672 }
 673
 674 static struct ecryptfs_cache_info {
 675         struct kmem_cache **cache;
 676         const char *name;
 677         size_t size;
 678         void (*ctor)(void *obj);
 679 } ecryptfs_cache_infos[] = {
 680         {
 681                 .cache = &ecryptfs_auth_tok_list_item_cache,
 682                 .name = "ecryptfs_auth_tok_list_item",
 683                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 684         },
 685         {
 686                 .cache = &ecryptfs_file_info_cache,
 687                 .name = "ecryptfs_file_cache",
 688                 .size = sizeof(struct ecryptfs_file_info),
 689         },
 690         {
 691                 .cache = &ecryptfs_dentry_info_cache,
 692                 .name = "ecryptfs_dentry_info_cache",
 693                 .size = sizeof(struct ecryptfs_dentry_info),
 694         },
 695         {
 696                 .cache = &ecryptfs_inode_info_cache,
 697                 .name = "ecryptfs_inode_cache",
 698                 .size = sizeof(struct ecryptfs_inode_info),
 699                 .ctor = inode_info_init_once,
 700         },
 701         {
 702                 .cache = &ecryptfs_sb_info_cache,
 703                 .name = "ecryptfs_sb_cache",
 704                 .size = sizeof(struct ecryptfs_sb_info),
 705         },
 706         {
 707                 .cache = &ecryptfs_header_cache_1,
 708                 .name = "ecryptfs_headers_1",
 709                 .size = PAGE_CACHE_SIZE,
 710         },
 711         {
 712                 .cache = &ecryptfs_header_cache_2,
 713                 .name = "ecryptfs_headers_2",
 714                 .size = PAGE_CACHE_SIZE,
 715         },
 716         {
 717                 .cache = &ecryptfs_xattr_cache,
 718                 .name = "ecryptfs_xattr_cache",
 719                 .size = PAGE_CACHE_SIZE,
 720         },
 721         {
 722                 .cache = &ecryptfs_key_record_cache,
 723                 .name = "ecryptfs_key_record_cache",
 724                 .size = sizeof(struct ecryptfs_key_record),
 725         },
 726         {
 727                 .cache = &ecryptfs_key_sig_cache,
 728                 .name = "ecryptfs_key_sig_cache",
 729                 .size = sizeof(struct ecryptfs_key_sig),
 730         },
 731         {
 732                 .cache = &ecryptfs_global_auth_tok_cache,
 733                 .name = "ecryptfs_global_auth_tok_cache",
 734                 .size = sizeof(struct ecryptfs_global_auth_tok),
 735         },
 736         {
 737                 .cache = &ecryptfs_key_tfm_cache,
 738                 .name = "ecryptfs_key_tfm_cache",
 739                 .size = sizeof(struct ecryptfs_key_tfm),
 740         },
 741         {
 742                 .cache = &ecryptfs_open_req_cache,
 743                 .name = "ecryptfs_open_req_cache",
 744                 .size = sizeof(struct ecryptfs_open_req),
 745         },
 746 };
 747
 748 static void ecryptfs_free_kmem_caches(void)
 749 {
 750         int i;
 751
 752         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 753                 struct ecryptfs_cache_info *info;
 754
 755                 info = &ecryptfs_cache_infos[i];
 756                 if (*(info->cache))
 757                         kmem_cache_destroy(*(info->cache));
 758         }
 759 }
 760
 761 /**
 762  * ecryptfs_init_kmem_caches
 763  *
 764  * Returns zero on success; non-zero otherwise
 765  */
 766 static int ecryptfs_init_kmem_caches(void)
 767 {
 768         int i;
 769
 770         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 771                 struct ecryptfs_cache_info *info;
 772
 773                 info = &ecryptfs_cache_infos[i];
 774                 *(info->cache) = kmem_cache_create(info->name, info->size,
 775                                 0, SLAB_HWCACHE_ALIGN, info->ctor);
 776                 if (!*(info->cache)) {
 777                         ecryptfs_free_kmem_caches();
 778                         ecryptfs_printk(KERN_WARNING, "%s: "
 779                                         "kmem_cache_create failed\n",
 780                                         info->name);
 781                         return -ENOMEM;
 782                 }
 783         }
 784         return 0;
 785 }
 786
 787 static struct kobject *ecryptfs_kobj;
 788
 789 static ssize_t version_show(struct kobject *kobj,
 790                             struct kobj_attribute *attr, char *buff)
 791 {
 792         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 793 }
 794
 795 static struct kobj_attribute version_attr = __ATTR_RO(version);
 796
 797 static struct attribute *attributes[] = {
 798         &version_attr.attr,
 799         NULL,
 800 };
 801
 802 static struct attribute_group attr_group = {
 803         .attrs = attributes,
 804 };
 805
 806 static int do_sysfs_registration(void)
 807 {
 808         int rc;
 809
 810         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 811         if (!ecryptfs_kobj) {
 812                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
 813                 rc = -ENOMEM;
 814                 goto out;
 815         }
 816         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 817         if (rc) {
 818                 printk(KERN_ERR
 819                        "Unable to create ecryptfs version attributes\n");
 820                 kobject_put(ecryptfs_kobj);
 821         }
 822 out:
 823         return rc;
 824 }
 825
 826 static void do_sysfs_unregistration(void)
 827 {
 828         sysfs_remove_group(ecryptfs_kobj, &attr_group);
 829         kobject_put(ecryptfs_kobj);
 830 }
 831
 832 static int __init ecryptfs_init(void)
 833 {
 834         int rc;
 835
 836         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
 837                 rc = -EINVAL;
 838                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 839                                 "larger than the host's page size, and so "
 840                                 "eCryptfs cannot run on this system. The "
 841                                 "default eCryptfs extent size is [%u] bytes; "
 842                                 "the page size is [%lu] bytes.\n",
 843                                 ECRYPTFS_DEFAULT_EXTENT_SIZE,
 844                                 (unsigned long)PAGE_CACHE_SIZE);
 845                 goto out;
 846         }
 847         rc = ecryptfs_init_kmem_caches();
 848         if (rc) {
 849                 printk(KERN_ERR
 850                        "Failed to allocate one or more kmem_cache objects\n");
 851                 goto out;
 852         }
 853         rc = register_filesystem(&ecryptfs_fs_type);
 854         if (rc) {
 855                 printk(KERN_ERR "Failed to register filesystem\n");
 856                 goto out_free_kmem_caches;
 857         }
 858         rc = do_sysfs_registration();
 859         if (rc) {
 860                 printk(KERN_ERR "sysfs registration failed\n");
 861                 goto out_unregister_filesystem;
 862         }
 863         rc = ecryptfs_init_kthread();
 864         if (rc) {
 865                 printk(KERN_ERR "%s: kthread initialization failed; "
 866                        "rc = [%d]\n", __func__, rc);
 867                 goto out_do_sysfs_unregistration;
 868         }
 869         rc = ecryptfs_init_messaging();
 870         if (rc) {
 871                 printk(KERN_ERR "Failure occurred while attempting to "
 872                                 "initialize the communications channel to "
 873                                 "ecryptfsd\n");
 874                 goto out_destroy_kthread;
 875         }
 876         rc = ecryptfs_init_crypto();
 877         if (rc) {
 878                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
 879                        "rc = [%d]\n", rc);
 880                 goto out_release_messaging;
 881         }
 882         if (ecryptfs_verbosity > 0)
 883                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 884                         "will be written to the syslog!\n", ecryptfs_verbosity);
 885
 886         goto out;
 887 out_release_messaging:
 888         ecryptfs_release_messaging();
 889 out_destroy_kthread:
 890         ecryptfs_destroy_kthread();
 891 out_do_sysfs_unregistration:
 892         do_sysfs_unregistration();
 893 out_unregister_filesystem:
 894         unregister_filesystem(&ecryptfs_fs_type);
 895 out_free_kmem_caches:
 896         ecryptfs_free_kmem_caches();
 897 out:
 898         return rc;
 899 }
 900
 901 static void __exit ecryptfs_exit(void)
 902 {
 903         int rc;
 904
 905         rc = ecryptfs_destroy_crypto();
 906         if (rc)
 907                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 908                        "rc = [%d]\n", rc);
 909         ecryptfs_release_messaging();
 910         ecryptfs_destroy_kthread();
 911         do_sysfs_unregistration();
 912         unregister_filesystem(&ecryptfs_fs_type);
 913         ecryptfs_free_kmem_caches();
 914 }
 915
 916 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 917 MODULE_DESCRIPTION("eCryptfs");
 918
 919 MODULE_LICENSE("GPL");
 920
 921 module_init(ecryptfs_init)
 922 module_exit(ecryptfs_exit)