release/src-rt-6.x.4708/linux/linux-2.6.36/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 "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 rc = 0;
 123
 124         mutex_lock(&inode_info->lower_file_mutex);
 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         mutex_unlock(&inode_info->lower_file_mutex);
 141         return rc;
 142 }
 143
 144 /**
 145  * ecryptfs_interpose
 146  * @lower_dentry: Existing dentry in the lower filesystem
 147  * @dentry: ecryptfs' dentry
 148  * @sb: ecryptfs's super_block
 149  * @flags: flags to govern behavior of interpose procedure
 150  *
 151  * Interposes upper and lower dentries.
 152  *
 153  * Returns zero on success; non-zero otherwise
 154  */
 155 int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
 156                        struct super_block *sb, u32 flags)
 157 {
 158         struct inode *lower_inode;
 159         struct inode *inode;
 160         int rc = 0;
 161
 162         lower_inode = lower_dentry->d_inode;
 163         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) {
 164                 rc = -EXDEV;
 165                 goto out;
 166         }
 167         if (!igrab(lower_inode)) {
 168                 rc = -ESTALE;
 169                 goto out;
 170         }
 171         inode = iget5_locked(sb, (unsigned long)lower_inode,
 172                              ecryptfs_inode_test, ecryptfs_inode_set,
 173                              lower_inode);
 174         if (!inode) {
 175                 rc = -EACCES;
 176                 iput(lower_inode);
 177                 goto out;
 178         }
 179         if (inode->i_state & I_NEW)
 180                 unlock_new_inode(inode);
 181         else
 182                 iput(lower_inode);
 183         if (S_ISLNK(lower_inode->i_mode))
 184                 inode->i_op = &ecryptfs_symlink_iops;
 185         else if (S_ISDIR(lower_inode->i_mode))
 186                 inode->i_op = &ecryptfs_dir_iops;
 187         if (S_ISDIR(lower_inode->i_mode))
 188                 inode->i_fop = &ecryptfs_dir_fops;
 189         if (special_file(lower_inode->i_mode))
 190                 init_special_inode(inode, lower_inode->i_mode,
 191                                    lower_inode->i_rdev);
 192         dentry->d_op = &ecryptfs_dops;
 193         fsstack_copy_attr_all(inode, lower_inode);
 194         /* This size will be overwritten for real files w/ headers and
 195          * other metadata */
 196         fsstack_copy_inode_size(inode, lower_inode);
 197         if (flags & ECRYPTFS_INTERPOSE_FLAG_D_ADD)
 198                 d_add(dentry, inode);
 199         else
 200                 d_instantiate(dentry, inode);
 201 out:
 202         return rc;
 203 }
 204
 205 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
 206        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
 207        ecryptfs_opt_ecryptfs_key_bytes,
 208        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
 209        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
 210        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
 211        ecryptfs_opt_unlink_sigs, ecryptfs_opt_err };
 212
 213 static const match_table_t tokens = {
 214         {ecryptfs_opt_sig, "sig=%s"},
 215         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 216         {ecryptfs_opt_cipher, "cipher=%s"},
 217         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
 218         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
 219         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
 220         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
 221         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
 222         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
 223         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
 224         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
 225         {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
 226         {ecryptfs_opt_err, NULL}
 227 };
 228
 229 static int ecryptfs_init_global_auth_toks(
 230         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 231 {
 232         struct ecryptfs_global_auth_tok *global_auth_tok;
 233         int rc = 0;
 234
 235         list_for_each_entry(global_auth_tok,
 236                             &mount_crypt_stat->global_auth_tok_list,
 237                             mount_crypt_stat_list) {
 238                 rc = ecryptfs_keyring_auth_tok_for_sig(
 239                         &global_auth_tok->global_auth_tok_key,
 240                         &global_auth_tok->global_auth_tok,
 241                         global_auth_tok->sig);
 242                 if (rc) {
 243                         printk(KERN_ERR "Could not find valid key in user "
 244                                "session keyring for sig specified in mount "
 245                                "option: [%s]\n", global_auth_tok->sig);
 246                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 247                         goto out;
 248                 } else
 249                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
 250         }
 251 out:
 252         return rc;
 253 }
 254
 255 static void ecryptfs_init_mount_crypt_stat(
 256         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 257 {
 258         memset((void *)mount_crypt_stat, 0,
 259                sizeof(struct ecryptfs_mount_crypt_stat));
 260         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
 261         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
 262         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
 263 }
 264
 265 static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options)
 266 {
 267         char *p;
 268         int rc = 0;
 269         int sig_set = 0;
 270         int cipher_name_set = 0;
 271         int fn_cipher_name_set = 0;
 272         int cipher_key_bytes;
 273         int cipher_key_bytes_set = 0;
 274         int fn_cipher_key_bytes;
 275         int fn_cipher_key_bytes_set = 0;
 276         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 277                 &sbi->mount_crypt_stat;
 278         substring_t args[MAX_OPT_ARGS];
 279         int token;
 280         char *sig_src;
 281         char *cipher_name_dst;
 282         char *cipher_name_src;
 283         char *fn_cipher_name_dst;
 284         char *fn_cipher_name_src;
 285         char *fnek_dst;
 286         char *fnek_src;
 287         char *cipher_key_bytes_src;
 288         char *fn_cipher_key_bytes_src;
 289
 290         if (!options) {
 291                 rc = -EINVAL;
 292                 goto out;
 293         }
 294         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
 295         while ((p = strsep(&options, ",")) != NULL) {
 296                 if (!*p)
 297                         continue;
 298                 token = match_token(p, tokens, args);
 299                 switch (token) {
 300                 case ecryptfs_opt_sig:
 301                 case ecryptfs_opt_ecryptfs_sig:
 302                         sig_src = args[0].from;
 303                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
 304                                                           sig_src, 0);
 305                         if (rc) {
 306                                 printk(KERN_ERR "Error attempting to register "
 307                                        "global sig; rc = [%d]\n", rc);
 308                                 goto out;
 309                         }
 310                         sig_set = 1;
 311                         break;
 312                 case ecryptfs_opt_cipher:
 313                 case ecryptfs_opt_ecryptfs_cipher:
 314                         cipher_name_src = args[0].from;
 315                         cipher_name_dst =
 316                                 mount_crypt_stat->
 317                                 global_default_cipher_name;
 318                         strncpy(cipher_name_dst, cipher_name_src,
 319                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 320                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 321                         cipher_name_set = 1;
 322                         break;
 323                 case ecryptfs_opt_ecryptfs_key_bytes:
 324                         cipher_key_bytes_src = args[0].from;
 325                         cipher_key_bytes =
 326                                 (int)simple_strtol(cipher_key_bytes_src,
 327                                                    &cipher_key_bytes_src, 0);
 328                         mount_crypt_stat->global_default_cipher_key_size =
 329                                 cipher_key_bytes;
 330                         cipher_key_bytes_set = 1;
 331                         break;
 332                 case ecryptfs_opt_passthrough:
 333                         mount_crypt_stat->flags |=
 334                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 335                         break;
 336                 case ecryptfs_opt_xattr_metadata:
 337                         mount_crypt_stat->flags |=
 338                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 339                         break;
 340                 case ecryptfs_opt_encrypted_view:
 341                         mount_crypt_stat->flags |=
 342                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 343                         mount_crypt_stat->flags |=
 344                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 345                         break;
 346                 case ecryptfs_opt_fnek_sig:
 347                         fnek_src = args[0].from;
 348                         fnek_dst =
 349                                 mount_crypt_stat->global_default_fnek_sig;
 350                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
 351                         mount_crypt_stat->global_default_fnek_sig[
 352                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
 353                         rc = ecryptfs_add_global_auth_tok(
 354                                 mount_crypt_stat,
 355                                 mount_crypt_stat->global_default_fnek_sig,
 356                                 ECRYPTFS_AUTH_TOK_FNEK);
 357                         if (rc) {
 358                                 printk(KERN_ERR "Error attempting to register "
 359                                        "global fnek sig [%s]; rc = [%d]\n",
 360                                        mount_crypt_stat->global_default_fnek_sig,
 361                                        rc);
 362                                 goto out;
 363                         }
 364                         mount_crypt_stat->flags |=
 365                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 366                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 367                         break;
 368                 case ecryptfs_opt_fn_cipher:
 369                         fn_cipher_name_src = args[0].from;
 370                         fn_cipher_name_dst =
 371                                 mount_crypt_stat->global_default_fn_cipher_name;
 372                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
 373                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 374                         mount_crypt_stat->global_default_fn_cipher_name[
 375                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 376                         fn_cipher_name_set = 1;
 377                         break;
 378                 case ecryptfs_opt_fn_cipher_key_bytes:
 379                         fn_cipher_key_bytes_src = args[0].from;
 380                         fn_cipher_key_bytes =
 381                                 (int)simple_strtol(fn_cipher_key_bytes_src,
 382                                                    &fn_cipher_key_bytes_src, 0);
 383                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
 384                                 fn_cipher_key_bytes;
 385                         fn_cipher_key_bytes_set = 1;
 386                         break;
 387                 case ecryptfs_opt_unlink_sigs:
 388                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
 389                         break;
 390                 case ecryptfs_opt_err:
 391                 default:
 392                         printk(KERN_WARNING
 393                                "%s: eCryptfs: unrecognized option [%s]\n",
 394                                __func__, p);
 395                 }
 396         }
 397         if (!sig_set) {
 398                 rc = -EINVAL;
 399                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
 400                                 "auth tok signature as a mount "
 401                                 "parameter; see the eCryptfs README\n");
 402                 goto out;
 403         }
 404         if (!cipher_name_set) {
 405                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 406
 407                 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 408                 strcpy(mount_crypt_stat->global_default_cipher_name,
 409                        ECRYPTFS_DEFAULT_CIPHER);
 410         }
 411         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 412             && !fn_cipher_name_set)
 413                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
 414                        mount_crypt_stat->global_default_cipher_name);
 415         if (!cipher_key_bytes_set)
 416                 mount_crypt_stat->global_default_cipher_key_size = 0;
 417         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 418             && !fn_cipher_key_bytes_set)
 419                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
 420                         mount_crypt_stat->global_default_cipher_key_size;
 421         mutex_lock(&key_tfm_list_mutex);
 422         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
 423                                  NULL)) {
 424                 rc = ecryptfs_add_new_key_tfm(
 425                         NULL, mount_crypt_stat->global_default_cipher_name,
 426                         mount_crypt_stat->global_default_cipher_key_size);
 427                 if (rc) {
 428                         printk(KERN_ERR "Error attempting to initialize "
 429                                "cipher with name = [%s] and key size = [%td]; "
 430                                "rc = [%d]\n",
 431                                mount_crypt_stat->global_default_cipher_name,
 432                                mount_crypt_stat->global_default_cipher_key_size,
 433                                rc);
 434                         rc = -EINVAL;
 435                         mutex_unlock(&key_tfm_list_mutex);
 436                         goto out;
 437                 }
 438         }
 439         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 440             && !ecryptfs_tfm_exists(
 441                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
 442                 rc = ecryptfs_add_new_key_tfm(
 443                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
 444                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
 445                 if (rc) {
 446                         printk(KERN_ERR "Error attempting to initialize "
 447                                "cipher with name = [%s] and key size = [%td]; "
 448                                "rc = [%d]\n",
 449                                mount_crypt_stat->global_default_fn_cipher_name,
 450                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
 451                                rc);
 452                         rc = -EINVAL;
 453                         mutex_unlock(&key_tfm_list_mutex);
 454                         goto out;
 455                 }
 456         }
 457         mutex_unlock(&key_tfm_list_mutex);
 458         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
 459         if (rc)
 460                 printk(KERN_WARNING "One or more global auth toks could not "
 461                        "properly register; rc = [%d]\n", rc);
 462 out:
 463         return rc;
 464 }
 465
 466 struct kmem_cache *ecryptfs_sb_info_cache;
 467 static struct file_system_type ecryptfs_fs_type;
 468
 469 /**
 470  * ecryptfs_read_super
 471  * @sb: The ecryptfs super block
 472  * @dev_name: The path to mount over
 473  *
 474  * Read the super block of the lower filesystem, and use
 475  * ecryptfs_interpose to create our initial inode and super block
 476  * struct.
 477  */
 478 static int ecryptfs_read_super(struct super_block *sb, const char *dev_name)
 479 {
 480         struct path path;
 481         int rc;
 482
 483         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 484         if (rc) {
 485                 ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n");
 486                 goto out;
 487         }
 488         if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
 489                 rc = -EINVAL;
 490                 printk(KERN_ERR "Mount on filesystem of type "
 491                         "eCryptfs explicitly disallowed due to "
 492                         "known incompatibilities\n");
 493                 goto out_free;
 494         }
 495         ecryptfs_set_superblock_lower(sb, path.dentry->d_sb);
 496         sb->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 497         sb->s_blocksize = path.dentry->d_sb->s_blocksize;
 498         ecryptfs_set_dentry_lower(sb->s_root, path.dentry);
 499         ecryptfs_set_dentry_lower_mnt(sb->s_root, path.mnt);
 500         rc = ecryptfs_interpose(path.dentry, sb->s_root, sb, 0);
 501         if (rc)
 502                 goto out_free;
 503         rc = 0;
 504         goto out;
 505 out_free:
 506         path_put(&path);
 507 out:
 508         return rc;
 509 }
 510
 511 /**
 512  * ecryptfs_get_sb
 513  * @fs_type
 514  * @flags
 515  * @dev_name: The path to mount over
 516  * @raw_data: The options passed into the kernel
 517  *
 518  * The whole ecryptfs_get_sb process is broken into 3 functions:
 519  * ecryptfs_parse_options(): handle options passed to ecryptfs, if any
 520  * ecryptfs_read_super(): this accesses the lower filesystem and uses
 521  *                        ecryptfs_interpose to perform most of the linking
 522  * ecryptfs_interpose(): links the lower filesystem into ecryptfs (inode.c)
 523  */
 524 static int ecryptfs_get_sb(struct file_system_type *fs_type, int flags,
 525                         const char *dev_name, void *raw_data,
 526                         struct vfsmount *mnt)
 527 {
 528         struct super_block *s;
 529         struct ecryptfs_sb_info *sbi;
 530         struct ecryptfs_dentry_info *root_info;
 531         const char *err = "Getting sb failed";
 532         int rc;
 533
 534         sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
 535         if (!sbi) {
 536                 rc = -ENOMEM;
 537                 goto out;
 538         }
 539
 540         rc = ecryptfs_parse_options(sbi, raw_data);
 541         if (rc) {
 542                 err = "Error parsing options";
 543                 goto out;
 544         }
 545
 546         s = sget(fs_type, NULL, set_anon_super, NULL);
 547         if (IS_ERR(s)) {
 548                 rc = PTR_ERR(s);
 549                 goto out;
 550         }
 551
 552         s->s_flags = flags;
 553         rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY);
 554         if (rc) {
 555                 deactivate_locked_super(s);
 556                 goto out;
 557         }
 558
 559         ecryptfs_set_superblock_private(s, sbi);
 560         s->s_bdi = &sbi->bdi;
 561
 562         /* ->kill_sb() will take care of sbi after that point */
 563         sbi = NULL;
 564         s->s_op = &ecryptfs_sops;
 565
 566         rc = -ENOMEM;
 567         s->s_root = d_alloc(NULL, &(const struct qstr) {
 568                              .hash = 0,.name = "/",.len = 1});
 569         if (!s->s_root) {
 570                 deactivate_locked_super(s);
 571                 goto out;
 572         }
 573         s->s_root->d_op = &ecryptfs_dops;
 574         s->s_root->d_sb = s;
 575         s->s_root->d_parent = s->s_root;
 576
 577         root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 578         if (!root_info) {
 579                 deactivate_locked_super(s);
 580                 goto out;
 581         }
 582         /* ->kill_sb() will take care of root_info */
 583         ecryptfs_set_dentry_private(s->s_root, root_info);
 584         s->s_flags |= MS_ACTIVE;
 585         rc = ecryptfs_read_super(s, dev_name);
 586         if (rc) {
 587                 deactivate_locked_super(s);
 588                 err = "Reading sb failed";
 589                 goto out;
 590         }
 591         simple_set_mnt(mnt, s);
 592         return 0;
 593
 594 out:
 595         if (sbi) {
 596                 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
 597                 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
 598         }
 599         printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
 600         return rc;
 601 }
 602
 603 /**
 604  * ecryptfs_kill_block_super
 605  * @sb: The ecryptfs super block
 606  *
 607  * Used to bring the superblock down and free the private data.
 608  */
 609 static void ecryptfs_kill_block_super(struct super_block *sb)
 610 {
 611         struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
 612         kill_anon_super(sb);
 613         if (!sb_info)
 614                 return;
 615         ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
 616         bdi_destroy(&sb_info->bdi);
 617         kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
 618 }
 619
 620 static struct file_system_type ecryptfs_fs_type = {
 621         .owner = THIS_MODULE,
 622         .name = "ecryptfs",
 623         .get_sb = ecryptfs_get_sb,
 624         .kill_sb = ecryptfs_kill_block_super,
 625         .fs_flags = 0
 626 };
 627
 628 /**
 629  * inode_info_init_once
 630  *
 631  * Initializes the ecryptfs_inode_info_cache when it is created
 632  */
 633 static void
 634 inode_info_init_once(void *vptr)
 635 {
 636         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 637
 638         inode_init_once(&ei->vfs_inode);
 639 }
 640
 641 static struct ecryptfs_cache_info {
 642         struct kmem_cache **cache;
 643         const char *name;
 644         size_t size;
 645         void (*ctor)(void *obj);
 646 } ecryptfs_cache_infos[] = {
 647         {
 648                 .cache = &ecryptfs_auth_tok_list_item_cache,
 649                 .name = "ecryptfs_auth_tok_list_item",
 650                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 651         },
 652         {
 653                 .cache = &ecryptfs_file_info_cache,
 654                 .name = "ecryptfs_file_cache",
 655                 .size = sizeof(struct ecryptfs_file_info),
 656         },
 657         {
 658                 .cache = &ecryptfs_dentry_info_cache,
 659                 .name = "ecryptfs_dentry_info_cache",
 660                 .size = sizeof(struct ecryptfs_dentry_info),
 661         },
 662         {
 663                 .cache = &ecryptfs_inode_info_cache,
 664                 .name = "ecryptfs_inode_cache",
 665                 .size = sizeof(struct ecryptfs_inode_info),
 666                 .ctor = inode_info_init_once,
 667         },
 668         {
 669                 .cache = &ecryptfs_sb_info_cache,
 670                 .name = "ecryptfs_sb_cache",
 671                 .size = sizeof(struct ecryptfs_sb_info),
 672         },
 673         {
 674                 .cache = &ecryptfs_header_cache_1,
 675                 .name = "ecryptfs_headers_1",
 676                 .size = PAGE_CACHE_SIZE,
 677         },
 678         {
 679                 .cache = &ecryptfs_header_cache_2,
 680                 .name = "ecryptfs_headers_2",
 681                 .size = PAGE_CACHE_SIZE,
 682         },
 683         {
 684                 .cache = &ecryptfs_xattr_cache,
 685                 .name = "ecryptfs_xattr_cache",
 686                 .size = PAGE_CACHE_SIZE,
 687         },
 688         {
 689                 .cache = &ecryptfs_key_record_cache,
 690                 .name = "ecryptfs_key_record_cache",
 691                 .size = sizeof(struct ecryptfs_key_record),
 692         },
 693         {
 694                 .cache = &ecryptfs_key_sig_cache,
 695                 .name = "ecryptfs_key_sig_cache",
 696                 .size = sizeof(struct ecryptfs_key_sig),
 697         },
 698         {
 699                 .cache = &ecryptfs_global_auth_tok_cache,
 700                 .name = "ecryptfs_global_auth_tok_cache",
 701                 .size = sizeof(struct ecryptfs_global_auth_tok),
 702         },
 703         {
 704                 .cache = &ecryptfs_key_tfm_cache,
 705                 .name = "ecryptfs_key_tfm_cache",
 706                 .size = sizeof(struct ecryptfs_key_tfm),
 707         },
 708         {
 709                 .cache = &ecryptfs_open_req_cache,
 710                 .name = "ecryptfs_open_req_cache",
 711                 .size = sizeof(struct ecryptfs_open_req),
 712         },
 713 };
 714
 715 static void ecryptfs_free_kmem_caches(void)
 716 {
 717         int i;
 718
 719         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 720                 struct ecryptfs_cache_info *info;
 721
 722                 info = &ecryptfs_cache_infos[i];
 723                 if (*(info->cache))
 724                         kmem_cache_destroy(*(info->cache));
 725         }
 726 }
 727
 728 /**
 729  * ecryptfs_init_kmem_caches
 730  *
 731  * Returns zero on success; non-zero otherwise
 732  */
 733 static int ecryptfs_init_kmem_caches(void)
 734 {
 735         int i;
 736
 737         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 738                 struct ecryptfs_cache_info *info;
 739
 740                 info = &ecryptfs_cache_infos[i];
 741                 *(info->cache) = kmem_cache_create(info->name, info->size,
 742                                 0, SLAB_HWCACHE_ALIGN, info->ctor);
 743                 if (!*(info->cache)) {
 744                         ecryptfs_free_kmem_caches();
 745                         ecryptfs_printk(KERN_WARNING, "%s: "
 746                                         "kmem_cache_create failed\n",
 747                                         info->name);
 748                         return -ENOMEM;
 749                 }
 750         }
 751         return 0;
 752 }
 753
 754 static struct kobject *ecryptfs_kobj;
 755
 756 static ssize_t version_show(struct kobject *kobj,
 757                             struct kobj_attribute *attr, char *buff)
 758 {
 759         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 760 }
 761
 762 static struct kobj_attribute version_attr = __ATTR_RO(version);
 763
 764 static struct attribute *attributes[] = {
 765         &version_attr.attr,
 766         NULL,
 767 };
 768
 769 static struct attribute_group attr_group = {
 770         .attrs = attributes,
 771 };
 772
 773 static int do_sysfs_registration(void)
 774 {
 775         int rc;
 776
 777         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 778         if (!ecryptfs_kobj) {
 779                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
 780                 rc = -ENOMEM;
 781                 goto out;
 782         }
 783         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 784         if (rc) {
 785                 printk(KERN_ERR
 786                        "Unable to create ecryptfs version attributes\n");
 787                 kobject_put(ecryptfs_kobj);
 788         }
 789 out:
 790         return rc;
 791 }
 792
 793 static void do_sysfs_unregistration(void)
 794 {
 795         sysfs_remove_group(ecryptfs_kobj, &attr_group);
 796         kobject_put(ecryptfs_kobj);
 797 }
 798
 799 static int __init ecryptfs_init(void)
 800 {
 801         int rc;
 802
 803         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
 804                 rc = -EINVAL;
 805                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 806                                 "larger than the host's page size, and so "
 807                                 "eCryptfs cannot run on this system. The "
 808                                 "default eCryptfs extent size is [%d] bytes; "
 809                                 "the page size is [%d] bytes.\n",
 810                                 ECRYPTFS_DEFAULT_EXTENT_SIZE, PAGE_CACHE_SIZE);
 811                 goto out;
 812         }
 813         rc = ecryptfs_init_kmem_caches();
 814         if (rc) {
 815                 printk(KERN_ERR
 816                        "Failed to allocate one or more kmem_cache objects\n");
 817                 goto out;
 818         }
 819         rc = register_filesystem(&ecryptfs_fs_type);
 820         if (rc) {
 821                 printk(KERN_ERR "Failed to register filesystem\n");
 822                 goto out_free_kmem_caches;
 823         }
 824         rc = do_sysfs_registration();
 825         if (rc) {
 826                 printk(KERN_ERR "sysfs registration failed\n");
 827                 goto out_unregister_filesystem;
 828         }
 829         rc = ecryptfs_init_kthread();
 830         if (rc) {
 831                 printk(KERN_ERR "%s: kthread initialization failed; "
 832                        "rc = [%d]\n", __func__, rc);
 833                 goto out_do_sysfs_unregistration;
 834         }
 835         rc = ecryptfs_init_messaging();
 836         if (rc) {
 837                 printk(KERN_ERR "Failure occured while attempting to "
 838                                 "initialize the communications channel to "
 839                                 "ecryptfsd\n");
 840                 goto out_destroy_kthread;
 841         }
 842         rc = ecryptfs_init_crypto();
 843         if (rc) {
 844                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
 845                        "rc = [%d]\n", rc);
 846                 goto out_release_messaging;
 847         }
 848         if (ecryptfs_verbosity > 0)
 849                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 850                         "will be written to the syslog!\n", ecryptfs_verbosity);
 851
 852         goto out;
 853 out_release_messaging:
 854         ecryptfs_release_messaging();
 855 out_destroy_kthread:
 856         ecryptfs_destroy_kthread();
 857 out_do_sysfs_unregistration:
 858         do_sysfs_unregistration();
 859 out_unregister_filesystem:
 860         unregister_filesystem(&ecryptfs_fs_type);
 861 out_free_kmem_caches:
 862         ecryptfs_free_kmem_caches();
 863 out:
 864         return rc;
 865 }
 866
 867 static void __exit ecryptfs_exit(void)
 868 {
 869         int rc;
 870
 871         rc = ecryptfs_destroy_crypto();
 872         if (rc)
 873                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 874                        "rc = [%d]\n", rc);
 875         ecryptfs_release_messaging();
 876         ecryptfs_destroy_kthread();
 877         do_sysfs_unregistration();
 878         unregister_filesystem(&ecryptfs_fs_type);
 879         ecryptfs_free_kmem_caches();
 880 }
 881
 882 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 883 MODULE_DESCRIPTION("eCryptfs");
 884
 885 MODULE_LICENSE("GPL");
 886
 887 module_init(ecryptfs_init)
 888 module_exit(ecryptfs_exit)