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, struct inode *inode)
 139 {
 140         struct ecryptfs_inode_info *inode_info;
 141         int count, rc = 0;
 142
 143         inode_info = ecryptfs_inode_to_private(inode);
 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 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
 172        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
 173        ecryptfs_opt_ecryptfs_key_bytes,
 174        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
 175        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
 176        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
 177        ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
 178        ecryptfs_opt_check_dev_ruid,
 179        ecryptfs_opt_err };
 180
 181 static const match_table_t tokens = {
 182         {ecryptfs_opt_sig, "sig=%s"},
 183         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 184         {ecryptfs_opt_cipher, "cipher=%s"},
 185         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
 186         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
 187         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
 188         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
 189         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
 190         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
 191         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
 192         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
 193         {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
 194         {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
 195         {ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
 196         {ecryptfs_opt_err, NULL}
 197 };
 198
 199 static int ecryptfs_init_global_auth_toks(
 200         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 201 {
 202         struct ecryptfs_global_auth_tok *global_auth_tok;
 203         struct ecryptfs_auth_tok *auth_tok;
 204         int rc = 0;
 205
 206         list_for_each_entry(global_auth_tok,
 207                             &mount_crypt_stat->global_auth_tok_list,
 208                             mount_crypt_stat_list) {
 209                 rc = ecryptfs_keyring_auth_tok_for_sig(
 210                         &global_auth_tok->global_auth_tok_key, &auth_tok,
 211                         global_auth_tok->sig);
 212                 if (rc) {
 213                         printk(KERN_ERR "Could not find valid key in user "
 214                                "session keyring for sig specified in mount "
 215                                "option: [%s]\n", global_auth_tok->sig);
 216                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 217                         goto out;
 218                 } else {
 219                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
 220                         up_write(&(global_auth_tok->global_auth_tok_key)->sem);
 221                 }
 222         }
 223 out:
 224         return rc;
 225 }
 226
 227 static void ecryptfs_init_mount_crypt_stat(
 228         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 229 {
 230         memset((void *)mount_crypt_stat, 0,
 231                sizeof(struct ecryptfs_mount_crypt_stat));
 232         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
 233         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
 234         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
 235 }
 236
 237 /**
 238  * ecryptfs_parse_options
 239  * @sb: The ecryptfs super block
 240  * @options: The options passed to the kernel
 241  * @check_ruid: set to 1 if device uid should be checked against the ruid
 242  *
 243  * Parse mount options:
 244  * debug=N         - ecryptfs_verbosity level for debug output
 245  * sig=XXX         - description(signature) of the key to use
 246  *
 247  * Returns the dentry object of the lower-level (lower/interposed)
 248  * directory; We want to mount our stackable file system on top of
 249  * that lower directory.
 250  *
 251  * The signature of the key to use must be the description of a key
 252  * already in the keyring. Mounting will fail if the key can not be
 253  * found.
 254  *
 255  * Returns zero on success; non-zero on error
 256  */
 257 static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
 258                                   uid_t *check_ruid)
 259 {
 260         char *p;
 261         int rc = 0;
 262         int sig_set = 0;
 263         int cipher_name_set = 0;
 264         int fn_cipher_name_set = 0;
 265         int cipher_key_bytes;
 266         int cipher_key_bytes_set = 0;
 267         int fn_cipher_key_bytes;
 268         int fn_cipher_key_bytes_set = 0;
 269         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 270                 &sbi->mount_crypt_stat;
 271         substring_t args[MAX_OPT_ARGS];
 272         int token;
 273         char *sig_src;
 274         char *cipher_name_dst;
 275         char *cipher_name_src;
 276         char *fn_cipher_name_dst;
 277         char *fn_cipher_name_src;
 278         char *fnek_dst;
 279         char *fnek_src;
 280         char *cipher_key_bytes_src;
 281         char *fn_cipher_key_bytes_src;
 282
 283         *check_ruid = 0;
 284
 285         if (!options) {
 286                 rc = -EINVAL;
 287                 goto out;
 288         }
 289         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
 290         while ((p = strsep(&options, ",")) != NULL) {
 291                 if (!*p)
 292                         continue;
 293                 token = match_token(p, tokens, args);
 294                 switch (token) {
 295                 case ecryptfs_opt_sig:
 296                 case ecryptfs_opt_ecryptfs_sig:
 297                         sig_src = args[0].from;
 298                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
 299                                                           sig_src, 0);
 300                         if (rc) {
 301                                 printk(KERN_ERR "Error attempting to register "
 302                                        "global sig; rc = [%d]\n", rc);
 303                                 goto out;
 304                         }
 305                         sig_set = 1;
 306                         break;
 307                 case ecryptfs_opt_cipher:
 308                 case ecryptfs_opt_ecryptfs_cipher:
 309                         cipher_name_src = args[0].from;
 310                         cipher_name_dst =
 311                                 mount_crypt_stat->
 312                                 global_default_cipher_name;
 313                         strncpy(cipher_name_dst, cipher_name_src,
 314                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 315                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 316                         cipher_name_set = 1;
 317                         break;
 318                 case ecryptfs_opt_ecryptfs_key_bytes:
 319                         cipher_key_bytes_src = args[0].from;
 320                         cipher_key_bytes =
 321                                 (int)simple_strtol(cipher_key_bytes_src,
 322                                                    &cipher_key_bytes_src, 0);
 323                         mount_crypt_stat->global_default_cipher_key_size =
 324                                 cipher_key_bytes;
 325                         cipher_key_bytes_set = 1;
 326                         break;
 327                 case ecryptfs_opt_passthrough:
 328                         mount_crypt_stat->flags |=
 329                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 330                         break;
 331                 case ecryptfs_opt_xattr_metadata:
 332                         mount_crypt_stat->flags |=
 333                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 334                         break;
 335                 case ecryptfs_opt_encrypted_view:
 336                         mount_crypt_stat->flags |=
 337                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 338                         mount_crypt_stat->flags |=
 339                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 340                         break;
 341                 case ecryptfs_opt_fnek_sig:
 342                         fnek_src = args[0].from;
 343                         fnek_dst =
 344                                 mount_crypt_stat->global_default_fnek_sig;
 345                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
 346                         mount_crypt_stat->global_default_fnek_sig[
 347                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
 348                         rc = ecryptfs_add_global_auth_tok(
 349                                 mount_crypt_stat,
 350                                 mount_crypt_stat->global_default_fnek_sig,
 351                                 ECRYPTFS_AUTH_TOK_FNEK);
 352                         if (rc) {
 353                                 printk(KERN_ERR "Error attempting to register "
 354                                        "global fnek sig [%s]; rc = [%d]\n",
 355                                        mount_crypt_stat->global_default_fnek_sig,
 356                                        rc);
 357                                 goto out;
 358                         }
 359                         mount_crypt_stat->flags |=
 360                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 361                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 362                         break;
 363                 case ecryptfs_opt_fn_cipher:
 364                         fn_cipher_name_src = args[0].from;
 365                         fn_cipher_name_dst =
 366                                 mount_crypt_stat->global_default_fn_cipher_name;
 367                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
 368                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 369                         mount_crypt_stat->global_default_fn_cipher_name[
 370                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 371                         fn_cipher_name_set = 1;
 372                         break;
 373                 case ecryptfs_opt_fn_cipher_key_bytes:
 374                         fn_cipher_key_bytes_src = args[0].from;
 375                         fn_cipher_key_bytes =
 376                                 (int)simple_strtol(fn_cipher_key_bytes_src,
 377                                                    &fn_cipher_key_bytes_src, 0);
 378                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
 379                                 fn_cipher_key_bytes;
 380                         fn_cipher_key_bytes_set = 1;
 381                         break;
 382                 case ecryptfs_opt_unlink_sigs:
 383                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
 384                         break;
 385                 case ecryptfs_opt_mount_auth_tok_only:
 386                         mount_crypt_stat->flags |=
 387                                 ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
 388                         break;
 389                 case ecryptfs_opt_check_dev_ruid:
 390                         *check_ruid = 1;
 391                         break;
 392                 case ecryptfs_opt_err:
 393                 default:
 394                         printk(KERN_WARNING
 395                                "%s: eCryptfs: unrecognized option [%s]\n",
 396                                __func__, p);
 397                 }
 398         }
 399         if (!sig_set) {
 400                 rc = -EINVAL;
 401                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
 402                                 "auth tok signature as a mount "
 403                                 "parameter; see the eCryptfs README\n");
 404                 goto out;
 405         }
 406         if (!cipher_name_set) {
 407                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 408
 409                 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 410                 strcpy(mount_crypt_stat->global_default_cipher_name,
 411                        ECRYPTFS_DEFAULT_CIPHER);
 412         }
 413         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 414             && !fn_cipher_name_set)
 415                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
 416                        mount_crypt_stat->global_default_cipher_name);
 417         if (!cipher_key_bytes_set)
 418                 mount_crypt_stat->global_default_cipher_key_size = 0;
 419         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 420             && !fn_cipher_key_bytes_set)
 421                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
 422                         mount_crypt_stat->global_default_cipher_key_size;
 423         mutex_lock(&key_tfm_list_mutex);
 424         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
 425                                  NULL)) {
 426                 rc = ecryptfs_add_new_key_tfm(
 427                         NULL, mount_crypt_stat->global_default_cipher_name,
 428                         mount_crypt_stat->global_default_cipher_key_size);
 429                 if (rc) {
 430                         printk(KERN_ERR "Error attempting to initialize "
 431                                "cipher with name = [%s] and key size = [%td]; "
 432                                "rc = [%d]\n",
 433                                mount_crypt_stat->global_default_cipher_name,
 434                                mount_crypt_stat->global_default_cipher_key_size,
 435                                rc);
 436                         rc = -EINVAL;
 437                         mutex_unlock(&key_tfm_list_mutex);
 438                         goto out;
 439                 }
 440         }
 441         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 442             && !ecryptfs_tfm_exists(
 443                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
 444                 rc = ecryptfs_add_new_key_tfm(
 445                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
 446                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
 447                 if (rc) {
 448                         printk(KERN_ERR "Error attempting to initialize "
 449                                "cipher with name = [%s] and key size = [%td]; "
 450                                "rc = [%d]\n",
 451                                mount_crypt_stat->global_default_fn_cipher_name,
 452                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
 453                                rc);
 454                         rc = -EINVAL;
 455                         mutex_unlock(&key_tfm_list_mutex);
 456                         goto out;
 457                 }
 458         }
 459         mutex_unlock(&key_tfm_list_mutex);
 460         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
 461         if (rc)
 462                 printk(KERN_WARNING "One or more global auth toks could not "
 463                        "properly register; rc = [%d]\n", rc);
 464 out:
 465         return rc;
 466 }
 467
 468 struct kmem_cache *ecryptfs_sb_info_cache;
 469 static struct file_system_type ecryptfs_fs_type;
 470
 471 /**
 472  * ecryptfs_get_sb
 473  * @fs_type
 474  * @flags
 475  * @dev_name: The path to mount over
 476  * @raw_data: The options passed into the kernel
 477  */
 478 static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
 479                         const char *dev_name, void *raw_data)
 480 {
 481         struct super_block *s;
 482         struct ecryptfs_sb_info *sbi;
 483         struct ecryptfs_dentry_info *root_info;
 484         const char *err = "Getting sb failed";
 485         struct inode *inode;
 486         struct path path;
 487         uid_t check_ruid;
 488         int rc;
 489
 490         sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
 491         if (!sbi) {
 492                 rc = -ENOMEM;
 493                 goto out;
 494         }
 495
 496         rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
 497         if (rc) {
 498                 err = "Error parsing options";
 499                 goto out;
 500         }
 501
 502         s = sget(fs_type, NULL, set_anon_super, NULL);
 503         if (IS_ERR(s)) {
 504                 rc = PTR_ERR(s);
 505                 goto out;
 506         }
 507
 508         s->s_flags = flags;
 509         rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY);
 510         if (rc)
 511                 goto out1;
 512
 513         ecryptfs_set_superblock_private(s, sbi);
 514         s->s_bdi = &sbi->bdi;
 515
 516         /* ->kill_sb() will take care of sbi after that point */
 517         sbi = NULL;
 518         s->s_op = &ecryptfs_sops;
 519         s->s_d_op = &ecryptfs_dops;
 520
 521         err = "Reading sb failed";
 522         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 523         if (rc) {
 524                 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
 525                 goto out1;
 526         }
 527         if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
 528                 rc = -EINVAL;
 529                 printk(KERN_ERR "Mount on filesystem of type "
 530                         "eCryptfs explicitly disallowed due to "
 531                         "known incompatibilities\n");
 532                 goto out_free;
 533         }
 534
 535         if (check_ruid && path.dentry->d_inode->i_uid != current_uid()) {
 536                 rc = -EPERM;
 537                 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
 538                        "requested user (uid: %d)\n",
 539                        path.dentry->d_inode->i_uid, current_uid());
 540                 goto out_free;
 541         }
 542
 543         ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
 544         s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 545         s->s_blocksize = path.dentry->d_sb->s_blocksize;
 546         s->s_magic = ECRYPTFS_SUPER_MAGIC;
 547
 548         inode = ecryptfs_get_inode(path.dentry->d_inode, s);
 549         rc = PTR_ERR(inode);
 550         if (IS_ERR(inode))
 551                 goto out_free;
 552
 553         s->s_root = d_alloc_root(inode);
 554         if (!s->s_root) {
 555                 iput(inode);
 556                 rc = -ENOMEM;
 557                 goto out_free;
 558         }
 559
 560         rc = -ENOMEM;
 561         root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 562         if (!root_info)
 563                 goto out_free;
 564
 565         /* ->kill_sb() will take care of root_info */
 566         ecryptfs_set_dentry_private(s->s_root, root_info);
 567         ecryptfs_set_dentry_lower(s->s_root, path.dentry);
 568         ecryptfs_set_dentry_lower_mnt(s->s_root, path.mnt);
 569
 570         s->s_flags |= MS_ACTIVE;
 571         return dget(s->s_root);
 572
 573 out_free:
 574         path_put(&path);
 575 out1:
 576         deactivate_locked_super(s);
 577 out:
 578         if (sbi) {
 579                 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
 580                 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
 581         }
 582         printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
 583         return ERR_PTR(rc);
 584 }
 585
 586 /**
 587  * ecryptfs_kill_block_super
 588  * @sb: The ecryptfs super block
 589  *
 590  * Used to bring the superblock down and free the private data.
 591  */
 592 static void ecryptfs_kill_block_super(struct super_block *sb)
 593 {
 594         struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
 595         kill_anon_super(sb);
 596         if (!sb_info)
 597                 return;
 598         ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
 599         bdi_destroy(&sb_info->bdi);
 600         kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
 601 }
 602
 603 static struct file_system_type ecryptfs_fs_type = {
 604         .owner = THIS_MODULE,
 605         .name = "ecryptfs",
 606         .mount = ecryptfs_mount,
 607         .kill_sb = ecryptfs_kill_block_super,
 608         .fs_flags = 0
 609 };
 610
 611 /**
 612  * inode_info_init_once
 613  *
 614  * Initializes the ecryptfs_inode_info_cache when it is created
 615  */
 616 static void
 617 inode_info_init_once(void *vptr)
 618 {
 619         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 620
 621         inode_init_once(&ei->vfs_inode);
 622 }
 623
 624 static struct ecryptfs_cache_info {
 625         struct kmem_cache **cache;
 626         const char *name;
 627         size_t size;
 628         void (*ctor)(void *obj);
 629 } ecryptfs_cache_infos[] = {
 630         {
 631                 .cache = &ecryptfs_auth_tok_list_item_cache,
 632                 .name = "ecryptfs_auth_tok_list_item",
 633                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 634         },
 635         {
 636                 .cache = &ecryptfs_file_info_cache,
 637                 .name = "ecryptfs_file_cache",
 638                 .size = sizeof(struct ecryptfs_file_info),
 639         },
 640         {
 641                 .cache = &ecryptfs_dentry_info_cache,
 642                 .name = "ecryptfs_dentry_info_cache",
 643                 .size = sizeof(struct ecryptfs_dentry_info),
 644         },
 645         {
 646                 .cache = &ecryptfs_inode_info_cache,
 647                 .name = "ecryptfs_inode_cache",
 648                 .size = sizeof(struct ecryptfs_inode_info),
 649                 .ctor = inode_info_init_once,
 650         },
 651         {
 652                 .cache = &ecryptfs_sb_info_cache,
 653                 .name = "ecryptfs_sb_cache",
 654                 .size = sizeof(struct ecryptfs_sb_info),
 655         },
 656         {
 657                 .cache = &ecryptfs_header_cache,
 658                 .name = "ecryptfs_headers",
 659                 .size = PAGE_CACHE_SIZE,
 660         },
 661         {
 662                 .cache = &ecryptfs_xattr_cache,
 663                 .name = "ecryptfs_xattr_cache",
 664                 .size = PAGE_CACHE_SIZE,
 665         },
 666         {
 667                 .cache = &ecryptfs_key_record_cache,
 668                 .name = "ecryptfs_key_record_cache",
 669                 .size = sizeof(struct ecryptfs_key_record),
 670         },
 671         {
 672                 .cache = &ecryptfs_key_sig_cache,
 673                 .name = "ecryptfs_key_sig_cache",
 674                 .size = sizeof(struct ecryptfs_key_sig),
 675         },
 676         {
 677                 .cache = &ecryptfs_global_auth_tok_cache,
 678                 .name = "ecryptfs_global_auth_tok_cache",
 679                 .size = sizeof(struct ecryptfs_global_auth_tok),
 680         },
 681         {
 682                 .cache = &ecryptfs_key_tfm_cache,
 683                 .name = "ecryptfs_key_tfm_cache",
 684                 .size = sizeof(struct ecryptfs_key_tfm),
 685         },
 686         {
 687                 .cache = &ecryptfs_open_req_cache,
 688                 .name = "ecryptfs_open_req_cache",
 689                 .size = sizeof(struct ecryptfs_open_req),
 690         },
 691 };
 692
 693 static void ecryptfs_free_kmem_caches(void)
 694 {
 695         int i;
 696
 697         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 698                 struct ecryptfs_cache_info *info;
 699
 700                 info = &ecryptfs_cache_infos[i];
 701                 if (*(info->cache))
 702                         kmem_cache_destroy(*(info->cache));
 703         }
 704 }
 705
 706 /**
 707  * ecryptfs_init_kmem_caches
 708  *
 709  * Returns zero on success; non-zero otherwise
 710  */
 711 static int ecryptfs_init_kmem_caches(void)
 712 {
 713         int i;
 714
 715         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 716                 struct ecryptfs_cache_info *info;
 717
 718                 info = &ecryptfs_cache_infos[i];
 719                 *(info->cache) = kmem_cache_create(info->name, info->size,
 720                                 0, SLAB_HWCACHE_ALIGN, info->ctor);
 721                 if (!*(info->cache)) {
 722                         ecryptfs_free_kmem_caches();
 723                         ecryptfs_printk(KERN_WARNING, "%s: "
 724                                         "kmem_cache_create failed\n",
 725                                         info->name);
 726                         return -ENOMEM;
 727                 }
 728         }
 729         return 0;
 730 }
 731
 732 static struct kobject *ecryptfs_kobj;
 733
 734 static ssize_t version_show(struct kobject *kobj,
 735                             struct kobj_attribute *attr, char *buff)
 736 {
 737         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 738 }
 739
 740 static struct kobj_attribute version_attr = __ATTR_RO(version);
 741
 742 static struct attribute *attributes[] = {
 743         &version_attr.attr,
 744         NULL,
 745 };
 746
 747 static struct attribute_group attr_group = {
 748         .attrs = attributes,
 749 };
 750
 751 static int do_sysfs_registration(void)
 752 {
 753         int rc;
 754
 755         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 756         if (!ecryptfs_kobj) {
 757                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
 758                 rc = -ENOMEM;
 759                 goto out;
 760         }
 761         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 762         if (rc) {
 763                 printk(KERN_ERR
 764                        "Unable to create ecryptfs version attributes\n");
 765                 kobject_put(ecryptfs_kobj);
 766         }
 767 out:
 768         return rc;
 769 }
 770
 771 static void do_sysfs_unregistration(void)
 772 {
 773         sysfs_remove_group(ecryptfs_kobj, &attr_group);
 774         kobject_put(ecryptfs_kobj);
 775 }
 776
 777 static int __init ecryptfs_init(void)
 778 {
 779         int rc;
 780
 781         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
 782                 rc = -EINVAL;
 783                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 784                                 "larger than the host's page size, and so "
 785                                 "eCryptfs cannot run on this system. The "
 786                                 "default eCryptfs extent size is [%u] bytes; "
 787                                 "the page size is [%lu] bytes.\n",
 788                                 ECRYPTFS_DEFAULT_EXTENT_SIZE,
 789                                 (unsigned long)PAGE_CACHE_SIZE);
 790                 goto out;
 791         }
 792         rc = ecryptfs_init_kmem_caches();
 793         if (rc) {
 794                 printk(KERN_ERR
 795                        "Failed to allocate one or more kmem_cache objects\n");
 796                 goto out;
 797         }
 798         rc = register_filesystem(&ecryptfs_fs_type);
 799         if (rc) {
 800                 printk(KERN_ERR "Failed to register filesystem\n");
 801                 goto out_free_kmem_caches;
 802         }
 803         rc = do_sysfs_registration();
 804         if (rc) {
 805                 printk(KERN_ERR "sysfs registration failed\n");
 806                 goto out_unregister_filesystem;
 807         }
 808         rc = ecryptfs_init_kthread();
 809         if (rc) {
 810                 printk(KERN_ERR "%s: kthread initialization failed; "
 811                        "rc = [%d]\n", __func__, rc);
 812                 goto out_do_sysfs_unregistration;
 813         }
 814         rc = ecryptfs_init_messaging();
 815         if (rc) {
 816                 printk(KERN_ERR "Failure occurred while attempting to "
 817                                 "initialize the communications channel to "
 818                                 "ecryptfsd\n");
 819                 goto out_destroy_kthread;
 820         }
 821         rc = ecryptfs_init_crypto();
 822         if (rc) {
 823                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
 824                        "rc = [%d]\n", rc);
 825                 goto out_release_messaging;
 826         }
 827         if (ecryptfs_verbosity > 0)
 828                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 829                         "will be written to the syslog!\n", ecryptfs_verbosity);
 830
 831         goto out;
 832 out_release_messaging:
 833         ecryptfs_release_messaging();
 834 out_destroy_kthread:
 835         ecryptfs_destroy_kthread();
 836 out_do_sysfs_unregistration:
 837         do_sysfs_unregistration();
 838 out_unregister_filesystem:
 839         unregister_filesystem(&ecryptfs_fs_type);
 840 out_free_kmem_caches:
 841         ecryptfs_free_kmem_caches();
 842 out:
 843         return rc;
 844 }
 845
 846 static void __exit ecryptfs_exit(void)
 847 {
 848         int rc;
 849
 850         rc = ecryptfs_destroy_crypto();
 851         if (rc)
 852                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 853                        "rc = [%d]\n", rc);
 854         ecryptfs_release_messaging();
 855         ecryptfs_destroy_kthread();
 856         do_sysfs_unregistration();
 857         unregister_filesystem(&ecryptfs_fs_type);
 858         ecryptfs_free_kmem_caches();
 859 }
 860
 861 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 862 MODULE_DESCRIPTION("eCryptfs");
 863
 864 MODULE_LICENSE("GPL");
 865
 866 module_init(ecryptfs_init)
 867 module_exit(ecryptfs_exit)