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 path *path = ecryptfs_dentry_to_lower_path(dentry);
 124         int rc;
 125
 126         rc = ecryptfs_privileged_open(lower_file, path->dentry, path->mnt,
 127                                       cred);
 128         if (rc) {
 129                 printk(KERN_ERR "Error opening lower file "
 130                        "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
 131                        "rc = [%d]\n", path->dentry, path->mnt, rc);
 132                 (*lower_file) = NULL;
 133         }
 134         return rc;
 135 }
 136
 137 int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
 138 {
 139         struct ecryptfs_inode_info *inode_info;
 140         int count, rc = 0;
 141
 142         inode_info = ecryptfs_inode_to_private(inode);
 143         mutex_lock(&inode_info->lower_file_mutex);
 144         count = atomic_inc_return(&inode_info->lower_file_count);
 145         if (WARN_ON_ONCE(count < 1))
 146                 rc = -EINVAL;
 147         else if (count == 1) {
 148                 rc = ecryptfs_init_lower_file(dentry,
 149                                               &inode_info->lower_file);
 150                 if (rc)
 151                         atomic_set(&inode_info->lower_file_count, 0);
 152         }
 153         mutex_unlock(&inode_info->lower_file_mutex);
 154         return rc;
 155 }
 156
 157 void ecryptfs_put_lower_file(struct inode *inode)
 158 {
 159         struct ecryptfs_inode_info *inode_info;
 160
 161         inode_info = ecryptfs_inode_to_private(inode);
 162         if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
 163                                       &inode_info->lower_file_mutex)) {
 164                 filemap_write_and_wait(inode->i_mapping);
 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         u8 cipher_code;
 283
 284         *check_ruid = 0;
 285
 286         if (!options) {
 287                 rc = -EINVAL;
 288                 goto out;
 289         }
 290         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
 291         while ((p = strsep(&options, ",")) != NULL) {
 292                 if (!*p)
 293                         continue;
 294                 token = match_token(p, tokens, args);
 295                 switch (token) {
 296                 case ecryptfs_opt_sig:
 297                 case ecryptfs_opt_ecryptfs_sig:
 298                         sig_src = args[0].from;
 299                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
 300                                                           sig_src, 0);
 301                         if (rc) {
 302                                 printk(KERN_ERR "Error attempting to register "
 303                                        "global sig; rc = [%d]\n", rc);
 304                                 goto out;
 305                         }
 306                         sig_set = 1;
 307                         break;
 308                 case ecryptfs_opt_cipher:
 309                 case ecryptfs_opt_ecryptfs_cipher:
 310                         cipher_name_src = args[0].from;
 311                         cipher_name_dst =
 312                                 mount_crypt_stat->
 313                                 global_default_cipher_name;
 314                         strncpy(cipher_name_dst, cipher_name_src,
 315                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 316                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 317                         cipher_name_set = 1;
 318                         break;
 319                 case ecryptfs_opt_ecryptfs_key_bytes:
 320                         cipher_key_bytes_src = args[0].from;
 321                         cipher_key_bytes =
 322                                 (int)simple_strtol(cipher_key_bytes_src,
 323                                                    &cipher_key_bytes_src, 0);
 324                         mount_crypt_stat->global_default_cipher_key_size =
 325                                 cipher_key_bytes;
 326                         cipher_key_bytes_set = 1;
 327                         break;
 328                 case ecryptfs_opt_passthrough:
 329                         mount_crypt_stat->flags |=
 330                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 331                         break;
 332                 case ecryptfs_opt_xattr_metadata:
 333                         mount_crypt_stat->flags |=
 334                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 335                         break;
 336                 case ecryptfs_opt_encrypted_view:
 337                         mount_crypt_stat->flags |=
 338                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 339                         mount_crypt_stat->flags |=
 340                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 341                         break;
 342                 case ecryptfs_opt_fnek_sig:
 343                         fnek_src = args[0].from;
 344                         fnek_dst =
 345                                 mount_crypt_stat->global_default_fnek_sig;
 346                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
 347                         mount_crypt_stat->global_default_fnek_sig[
 348                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
 349                         rc = ecryptfs_add_global_auth_tok(
 350                                 mount_crypt_stat,
 351                                 mount_crypt_stat->global_default_fnek_sig,
 352                                 ECRYPTFS_AUTH_TOK_FNEK);
 353                         if (rc) {
 354                                 printk(KERN_ERR "Error attempting to register "
 355                                        "global fnek sig [%s]; rc = [%d]\n",
 356                                        mount_crypt_stat->global_default_fnek_sig,
 357                                        rc);
 358                                 goto out;
 359                         }
 360                         mount_crypt_stat->flags |=
 361                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 362                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 363                         break;
 364                 case ecryptfs_opt_fn_cipher:
 365                         fn_cipher_name_src = args[0].from;
 366                         fn_cipher_name_dst =
 367                                 mount_crypt_stat->global_default_fn_cipher_name;
 368                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
 369                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 370                         mount_crypt_stat->global_default_fn_cipher_name[
 371                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 372                         fn_cipher_name_set = 1;
 373                         break;
 374                 case ecryptfs_opt_fn_cipher_key_bytes:
 375                         fn_cipher_key_bytes_src = args[0].from;
 376                         fn_cipher_key_bytes =
 377                                 (int)simple_strtol(fn_cipher_key_bytes_src,
 378                                                    &fn_cipher_key_bytes_src, 0);
 379                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
 380                                 fn_cipher_key_bytes;
 381                         fn_cipher_key_bytes_set = 1;
 382                         break;
 383                 case ecryptfs_opt_unlink_sigs:
 384                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
 385                         break;
 386                 case ecryptfs_opt_mount_auth_tok_only:
 387                         mount_crypt_stat->flags |=
 388                                 ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
 389                         break;
 390                 case ecryptfs_opt_check_dev_ruid:
 391                         *check_ruid = 1;
 392                         break;
 393                 case ecryptfs_opt_err:
 394                 default:
 395                         printk(KERN_WARNING
 396                                "%s: eCryptfs: unrecognized option [%s]\n",
 397                                __func__, p);
 398                 }
 399         }
 400         if (!sig_set) {
 401                 rc = -EINVAL;
 402                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
 403                                 "auth tok signature as a mount "
 404                                 "parameter; see the eCryptfs README\n");
 405                 goto out;
 406         }
 407         if (!cipher_name_set) {
 408                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 409
 410                 BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 411                 strcpy(mount_crypt_stat->global_default_cipher_name,
 412                        ECRYPTFS_DEFAULT_CIPHER);
 413         }
 414         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 415             && !fn_cipher_name_set)
 416                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
 417                        mount_crypt_stat->global_default_cipher_name);
 418         if (!cipher_key_bytes_set)
 419                 mount_crypt_stat->global_default_cipher_key_size = 0;
 420         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 421             && !fn_cipher_key_bytes_set)
 422                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
 423                         mount_crypt_stat->global_default_cipher_key_size;
 424
 425         cipher_code = ecryptfs_code_for_cipher_string(
 426                 mount_crypt_stat->global_default_cipher_name,
 427                 mount_crypt_stat->global_default_cipher_key_size);
 428         if (!cipher_code) {
 429                 ecryptfs_printk(KERN_ERR,
 430                                 "eCryptfs doesn't support cipher: %s",
 431                                 mount_crypt_stat->global_default_cipher_name);
 432                 rc = -EINVAL;
 433                 goto out;
 434         }
 435
 436         mutex_lock(&key_tfm_list_mutex);
 437         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
 438                                  NULL)) {
 439                 rc = ecryptfs_add_new_key_tfm(
 440                         NULL, mount_crypt_stat->global_default_cipher_name,
 441                         mount_crypt_stat->global_default_cipher_key_size);
 442                 if (rc) {
 443                         printk(KERN_ERR "Error attempting to initialize "
 444                                "cipher with name = [%s] and key size = [%td]; "
 445                                "rc = [%d]\n",
 446                                mount_crypt_stat->global_default_cipher_name,
 447                                mount_crypt_stat->global_default_cipher_key_size,
 448                                rc);
 449                         rc = -EINVAL;
 450                         mutex_unlock(&key_tfm_list_mutex);
 451                         goto out;
 452                 }
 453         }
 454         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 455             && !ecryptfs_tfm_exists(
 456                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
 457                 rc = ecryptfs_add_new_key_tfm(
 458                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
 459                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
 460                 if (rc) {
 461                         printk(KERN_ERR "Error attempting to initialize "
 462                                "cipher with name = [%s] and key size = [%td]; "
 463                                "rc = [%d]\n",
 464                                mount_crypt_stat->global_default_fn_cipher_name,
 465                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
 466                                rc);
 467                         rc = -EINVAL;
 468                         mutex_unlock(&key_tfm_list_mutex);
 469                         goto out;
 470                 }
 471         }
 472         mutex_unlock(&key_tfm_list_mutex);
 473         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
 474         if (rc)
 475                 printk(KERN_WARNING "One or more global auth toks could not "
 476                        "properly register; rc = [%d]\n", rc);
 477 out:
 478         return rc;
 479 }
 480
 481 struct kmem_cache *ecryptfs_sb_info_cache;
 482 static struct file_system_type ecryptfs_fs_type;
 483
 484 /**
 485  * ecryptfs_get_sb
 486  * @fs_type
 487  * @flags
 488  * @dev_name: The path to mount over
 489  * @raw_data: The options passed into the kernel
 490  */
 491 static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
 492                         const char *dev_name, void *raw_data)
 493 {
 494         struct super_block *s;
 495         struct ecryptfs_sb_info *sbi;
 496         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 497         struct ecryptfs_dentry_info *root_info;
 498         const char *err = "Getting sb failed";
 499         struct inode *inode;
 500         struct path path;
 501         uid_t check_ruid;
 502         int rc;
 503
 504         sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
 505         if (!sbi) {
 506                 rc = -ENOMEM;
 507                 goto out;
 508         }
 509
 510         rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
 511         if (rc) {
 512                 err = "Error parsing options";
 513                 goto out;
 514         }
 515         mount_crypt_stat = &sbi->mount_crypt_stat;
 516
 517         s = sget(fs_type, NULL, set_anon_super, flags, NULL);
 518         if (IS_ERR(s)) {
 519                 rc = PTR_ERR(s);
 520                 goto out;
 521         }
 522
 523         rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs");
 524         if (rc)
 525                 goto out1;
 526
 527         ecryptfs_set_superblock_private(s, sbi);
 528         s->s_bdi = &sbi->bdi;
 529
 530         /* ->kill_sb() will take care of sbi after that point */
 531         sbi = NULL;
 532         s->s_op = &ecryptfs_sops;
 533         s->s_d_op = &ecryptfs_dops;
 534
 535         err = "Reading sb failed";
 536         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 537         if (rc) {
 538                 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
 539                 goto out1;
 540         }
 541         if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
 542                 rc = -EINVAL;
 543                 printk(KERN_ERR "Mount on filesystem of type "
 544                         "eCryptfs explicitly disallowed due to "
 545                         "known incompatibilities\n");
 546                 goto out_free;
 547         }
 548
 549         if (check_ruid && !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) {
 550                 rc = -EPERM;
 551                 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
 552                        "requested user (uid: %d)\n",
 553                         i_uid_read(d_inode(path.dentry)),
 554                         from_kuid(&init_user_ns, current_uid()));
 555                 goto out_free;
 556         }
 557
 558         ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
 559
 560         /**
 561          * Set the POSIX ACL flag based on whether they're enabled in the lower
 562          * mount.
 563          */
 564         s->s_flags = flags & ~MS_POSIXACL;
 565         s->s_flags |= path.dentry->d_sb->s_flags & MS_POSIXACL;
 566
 567         /**
 568          * Force a read-only eCryptfs mount when:
 569          *   1) The lower mount is ro
 570          *   2) The ecryptfs_encrypted_view mount option is specified
 571          */
 572         if (path.dentry->d_sb->s_flags & MS_RDONLY ||
 573             mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
 574                 s->s_flags |= MS_RDONLY;
 575
 576         s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 577         s->s_blocksize = path.dentry->d_sb->s_blocksize;
 578         s->s_magic = ECRYPTFS_SUPER_MAGIC;
 579         s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
 580
 581         rc = -EINVAL;
 582         if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
 583                 pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
 584                 goto out_free;
 585         }
 586
 587         inode = ecryptfs_get_inode(d_inode(path.dentry), s);
 588         rc = PTR_ERR(inode);
 589         if (IS_ERR(inode))
 590                 goto out_free;
 591
 592         s->s_root = d_make_root(inode);
 593         if (!s->s_root) {
 594                 rc = -ENOMEM;
 595                 goto out_free;
 596         }
 597
 598         rc = -ENOMEM;
 599         root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 600         if (!root_info)
 601                 goto out_free;
 602
 603         /* ->kill_sb() will take care of root_info */
 604         ecryptfs_set_dentry_private(s->s_root, root_info);
 605         root_info->lower_path = path;
 606
 607         s->s_flags |= MS_ACTIVE;
 608         return dget(s->s_root);
 609
 610 out_free:
 611         path_put(&path);
 612 out1:
 613         deactivate_locked_super(s);
 614 out:
 615         if (sbi) {
 616                 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
 617                 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
 618         }
 619         printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
 620         return ERR_PTR(rc);
 621 }
 622
 623 /**
 624  * ecryptfs_kill_block_super
 625  * @sb: The ecryptfs super block
 626  *
 627  * Used to bring the superblock down and free the private data.
 628  */
 629 static void ecryptfs_kill_block_super(struct super_block *sb)
 630 {
 631         struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
 632         kill_anon_super(sb);
 633         if (!sb_info)
 634                 return;
 635         ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
 636         bdi_destroy(&sb_info->bdi);
 637         kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
 638 }
 639
 640 static struct file_system_type ecryptfs_fs_type = {
 641         .owner = THIS_MODULE,
 642         .name = "ecryptfs",
 643         .mount = ecryptfs_mount,
 644         .kill_sb = ecryptfs_kill_block_super,
 645         .fs_flags = 0
 646 };
 647 MODULE_ALIAS_FS("ecryptfs");
 648
 649 /**
 650  * inode_info_init_once
 651  *
 652  * Initializes the ecryptfs_inode_info_cache when it is created
 653  */
 654 static void
 655 inode_info_init_once(void *vptr)
 656 {
 657         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 658
 659         inode_init_once(&ei->vfs_inode);
 660 }
 661
 662 static struct ecryptfs_cache_info {
 663         struct kmem_cache **cache;
 664         const char *name;
 665         size_t size;
 666         void (*ctor)(void *obj);
 667 } ecryptfs_cache_infos[] = {
 668         {
 669                 .cache = &ecryptfs_auth_tok_list_item_cache,
 670                 .name = "ecryptfs_auth_tok_list_item",
 671                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 672         },
 673         {
 674                 .cache = &ecryptfs_file_info_cache,
 675                 .name = "ecryptfs_file_cache",
 676                 .size = sizeof(struct ecryptfs_file_info),
 677         },
 678         {
 679                 .cache = &ecryptfs_dentry_info_cache,
 680                 .name = "ecryptfs_dentry_info_cache",
 681                 .size = sizeof(struct ecryptfs_dentry_info),
 682         },
 683         {
 684                 .cache = &ecryptfs_inode_info_cache,
 685                 .name = "ecryptfs_inode_cache",
 686                 .size = sizeof(struct ecryptfs_inode_info),
 687                 .ctor = inode_info_init_once,
 688         },
 689         {
 690                 .cache = &ecryptfs_sb_info_cache,
 691                 .name = "ecryptfs_sb_cache",
 692                 .size = sizeof(struct ecryptfs_sb_info),
 693         },
 694         {
 695                 .cache = &ecryptfs_header_cache,
 696                 .name = "ecryptfs_headers",
 697                 .size = PAGE_CACHE_SIZE,
 698         },
 699         {
 700                 .cache = &ecryptfs_xattr_cache,
 701                 .name = "ecryptfs_xattr_cache",
 702                 .size = PAGE_CACHE_SIZE,
 703         },
 704         {
 705                 .cache = &ecryptfs_key_record_cache,
 706                 .name = "ecryptfs_key_record_cache",
 707                 .size = sizeof(struct ecryptfs_key_record),
 708         },
 709         {
 710                 .cache = &ecryptfs_key_sig_cache,
 711                 .name = "ecryptfs_key_sig_cache",
 712                 .size = sizeof(struct ecryptfs_key_sig),
 713         },
 714         {
 715                 .cache = &ecryptfs_global_auth_tok_cache,
 716                 .name = "ecryptfs_global_auth_tok_cache",
 717                 .size = sizeof(struct ecryptfs_global_auth_tok),
 718         },
 719         {
 720                 .cache = &ecryptfs_key_tfm_cache,
 721                 .name = "ecryptfs_key_tfm_cache",
 722                 .size = sizeof(struct ecryptfs_key_tfm),
 723         },
 724 };
 725
 726 static void ecryptfs_free_kmem_caches(void)
 727 {
 728         int i;
 729
 730         /*
 731          * Make sure all delayed rcu free inodes are flushed before we
 732          * destroy cache.
 733          */
 734         rcu_barrier();
 735
 736         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 737                 struct ecryptfs_cache_info *info;
 738
 739                 info = &ecryptfs_cache_infos[i];
 740                 if (*(info->cache))
 741                         kmem_cache_destroy(*(info->cache));
 742         }
 743 }
 744
 745 /**
 746  * ecryptfs_init_kmem_caches
 747  *
 748  * Returns zero on success; non-zero otherwise
 749  */
 750 static int ecryptfs_init_kmem_caches(void)
 751 {
 752         int i;
 753
 754         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 755                 struct ecryptfs_cache_info *info;
 756
 757                 info = &ecryptfs_cache_infos[i];
 758                 *(info->cache) = kmem_cache_create(info->name, info->size,
 759                                 0, SLAB_HWCACHE_ALIGN, info->ctor);
 760                 if (!*(info->cache)) {
 761                         ecryptfs_free_kmem_caches();
 762                         ecryptfs_printk(KERN_WARNING, "%s: "
 763                                         "kmem_cache_create failed\n",
 764                                         info->name);
 765                         return -ENOMEM;
 766                 }
 767         }
 768         return 0;
 769 }
 770
 771 static struct kobject *ecryptfs_kobj;
 772
 773 static ssize_t version_show(struct kobject *kobj,
 774                             struct kobj_attribute *attr, char *buff)
 775 {
 776         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 777 }
 778
 779 static struct kobj_attribute version_attr = __ATTR_RO(version);
 780
 781 static struct attribute *attributes[] = {
 782         &version_attr.attr,
 783         NULL,
 784 };
 785
 786 static struct attribute_group attr_group = {
 787         .attrs = attributes,
 788 };
 789
 790 static int do_sysfs_registration(void)
 791 {
 792         int rc;
 793
 794         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 795         if (!ecryptfs_kobj) {
 796                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
 797                 rc = -ENOMEM;
 798                 goto out;
 799         }
 800         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 801         if (rc) {
 802                 printk(KERN_ERR
 803                        "Unable to create ecryptfs version attributes\n");
 804                 kobject_put(ecryptfs_kobj);
 805         }
 806 out:
 807         return rc;
 808 }
 809
 810 static void do_sysfs_unregistration(void)
 811 {
 812         sysfs_remove_group(ecryptfs_kobj, &attr_group);
 813         kobject_put(ecryptfs_kobj);
 814 }
 815
 816 static int __init ecryptfs_init(void)
 817 {
 818         int rc;
 819
 820         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
 821                 rc = -EINVAL;
 822                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 823                                 "larger than the host's page size, and so "
 824                                 "eCryptfs cannot run on this system. The "
 825                                 "default eCryptfs extent size is [%u] bytes; "
 826                                 "the page size is [%lu] bytes.\n",
 827                                 ECRYPTFS_DEFAULT_EXTENT_SIZE,
 828                                 (unsigned long)PAGE_CACHE_SIZE);
 829                 goto out;
 830         }
 831         rc = ecryptfs_init_kmem_caches();
 832         if (rc) {
 833                 printk(KERN_ERR
 834                        "Failed to allocate one or more kmem_cache objects\n");
 835                 goto out;
 836         }
 837         rc = do_sysfs_registration();
 838         if (rc) {
 839                 printk(KERN_ERR "sysfs registration failed\n");
 840                 goto out_free_kmem_caches;
 841         }
 842         rc = ecryptfs_init_kthread();
 843         if (rc) {
 844                 printk(KERN_ERR "%s: kthread initialization failed; "
 845                        "rc = [%d]\n", __func__, rc);
 846                 goto out_do_sysfs_unregistration;
 847         }
 848         rc = ecryptfs_init_messaging();
 849         if (rc) {
 850                 printk(KERN_ERR "Failure occurred while attempting to "
 851                                 "initialize the communications channel to "
 852                                 "ecryptfsd\n");
 853                 goto out_destroy_kthread;
 854         }
 855         rc = ecryptfs_init_crypto();
 856         if (rc) {
 857                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
 858                        "rc = [%d]\n", rc);
 859                 goto out_release_messaging;
 860         }
 861         rc = register_filesystem(&ecryptfs_fs_type);
 862         if (rc) {
 863                 printk(KERN_ERR "Failed to register filesystem\n");
 864                 goto out_destroy_crypto;
 865         }
 866         if (ecryptfs_verbosity > 0)
 867                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 868                         "will be written to the syslog!\n", ecryptfs_verbosity);
 869
 870         goto out;
 871 out_destroy_crypto:
 872         ecryptfs_destroy_crypto();
 873 out_release_messaging:
 874         ecryptfs_release_messaging();
 875 out_destroy_kthread:
 876         ecryptfs_destroy_kthread();
 877 out_do_sysfs_unregistration:
 878         do_sysfs_unregistration();
 879 out_free_kmem_caches:
 880         ecryptfs_free_kmem_caches();
 881 out:
 882         return rc;
 883 }
 884
 885 static void __exit ecryptfs_exit(void)
 886 {
 887         int rc;
 888
 889         rc = ecryptfs_destroy_crypto();
 890         if (rc)
 891                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 892                        "rc = [%d]\n", rc);
 893         ecryptfs_release_messaging();
 894         ecryptfs_destroy_kthread();
 895         do_sysfs_unregistration();
 896         unregister_filesystem(&ecryptfs_fs_type);
 897         ecryptfs_free_kmem_caches();
 898 }
 899
 900 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 901 MODULE_DESCRIPTION("eCryptfs");
 902
 903 MODULE_LICENSE("GPL");
 904
 905 module_init(ecryptfs_init)
 906 module_exit(ecryptfs_exit)