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_dentry_info *root_info;
 497         const char *err = "Getting sb failed";
 498         struct inode *inode;
 499         struct path path;
 500         uid_t check_ruid;
 501         int rc;
 502
 503         sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
 504         if (!sbi) {
 505                 rc = -ENOMEM;
 506                 goto out;
 507         }
 508
 509         rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
 510         if (rc) {
 511                 err = "Error parsing options";
 512                 goto out;
 513         }
 514
 515         s = sget(fs_type, NULL, set_anon_super, flags, NULL);
 516         if (IS_ERR(s)) {
 517                 rc = PTR_ERR(s);
 518                 goto out;
 519         }
 520
 521         rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY);
 522         if (rc)
 523                 goto out1;
 524
 525         ecryptfs_set_superblock_private(s, sbi);
 526         s->s_bdi = &sbi->bdi;
 527
 528         /* ->kill_sb() will take care of sbi after that point */
 529         sbi = NULL;
 530         s->s_op = &ecryptfs_sops;
 531         s->s_d_op = &ecryptfs_dops;
 532
 533         err = "Reading sb failed";
 534         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 535         if (rc) {
 536                 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
 537                 goto out1;
 538         }
 539         if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
 540                 rc = -EINVAL;
 541                 printk(KERN_ERR "Mount on filesystem of type "
 542                         "eCryptfs explicitly disallowed due to "
 543                         "known incompatibilities\n");
 544                 goto out_free;
 545         }
 546
 547         if (check_ruid && !uid_eq(path.dentry->d_inode->i_uid, current_uid())) {
 548                 rc = -EPERM;
 549                 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
 550                        "requested user (uid: %d)\n",
 551                         i_uid_read(path.dentry->d_inode),
 552                         from_kuid(&init_user_ns, current_uid()));
 553                 goto out_free;
 554         }
 555
 556         ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
 557
 558         /**
 559          * Set the POSIX ACL flag based on whether they're enabled in the lower
 560          * mount. Force a read-only eCryptfs mount if the lower mount is ro.
 561          * Allow a ro eCryptfs mount even when the lower mount is rw.
 562          */
 563         s->s_flags = flags & ~MS_POSIXACL;
 564         s->s_flags |= path.dentry->d_sb->s_flags & (MS_RDONLY | MS_POSIXACL);
 565
 566         s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 567         s->s_blocksize = path.dentry->d_sb->s_blocksize;
 568         s->s_magic = ECRYPTFS_SUPER_MAGIC;
 569
 570         inode = ecryptfs_get_inode(path.dentry->d_inode, s);
 571         rc = PTR_ERR(inode);
 572         if (IS_ERR(inode))
 573                 goto out_free;
 574
 575         s->s_root = d_make_root(inode);
 576         if (!s->s_root) {
 577                 rc = -ENOMEM;
 578                 goto out_free;
 579         }
 580
 581         rc = -ENOMEM;
 582         root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 583         if (!root_info)
 584                 goto out_free;
 585
 586         /* ->kill_sb() will take care of root_info */
 587         ecryptfs_set_dentry_private(s->s_root, root_info);
 588         root_info->lower_path = path;
 589
 590         s->s_flags |= MS_ACTIVE;
 591         return dget(s->s_root);
 592
 593 out_free:
 594         path_put(&path);
 595 out1:
 596         deactivate_locked_super(s);
 597 out:
 598         if (sbi) {
 599                 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
 600                 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
 601         }
 602         printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
 603         return ERR_PTR(rc);
 604 }
 605
 606 /**
 607  * ecryptfs_kill_block_super
 608  * @sb: The ecryptfs super block
 609  *
 610  * Used to bring the superblock down and free the private data.
 611  */
 612 static void ecryptfs_kill_block_super(struct super_block *sb)
 613 {
 614         struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
 615         kill_anon_super(sb);
 616         if (!sb_info)
 617                 return;
 618         ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
 619         bdi_destroy(&sb_info->bdi);
 620         kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
 621 }
 622
 623 static struct file_system_type ecryptfs_fs_type = {
 624         .owner = THIS_MODULE,
 625         .name = "ecryptfs",
 626         .mount = ecryptfs_mount,
 627         .kill_sb = ecryptfs_kill_block_super,
 628         .fs_flags = 0
 629 };
 630 MODULE_ALIAS_FS("ecryptfs");
 631
 632 /**
 633  * inode_info_init_once
 634  *
 635  * Initializes the ecryptfs_inode_info_cache when it is created
 636  */
 637 static void
 638 inode_info_init_once(void *vptr)
 639 {
 640         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 641
 642         inode_init_once(&ei->vfs_inode);
 643 }
 644
 645 static struct ecryptfs_cache_info {
 646         struct kmem_cache **cache;
 647         const char *name;
 648         size_t size;
 649         void (*ctor)(void *obj);
 650 } ecryptfs_cache_infos[] = {
 651         {
 652                 .cache = &ecryptfs_auth_tok_list_item_cache,
 653                 .name = "ecryptfs_auth_tok_list_item",
 654                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 655         },
 656         {
 657                 .cache = &ecryptfs_file_info_cache,
 658                 .name = "ecryptfs_file_cache",
 659                 .size = sizeof(struct ecryptfs_file_info),
 660         },
 661         {
 662                 .cache = &ecryptfs_dentry_info_cache,
 663                 .name = "ecryptfs_dentry_info_cache",
 664                 .size = sizeof(struct ecryptfs_dentry_info),
 665         },
 666         {
 667                 .cache = &ecryptfs_inode_info_cache,
 668                 .name = "ecryptfs_inode_cache",
 669                 .size = sizeof(struct ecryptfs_inode_info),
 670                 .ctor = inode_info_init_once,
 671         },
 672         {
 673                 .cache = &ecryptfs_sb_info_cache,
 674                 .name = "ecryptfs_sb_cache",
 675                 .size = sizeof(struct ecryptfs_sb_info),
 676         },
 677         {
 678                 .cache = &ecryptfs_header_cache,
 679                 .name = "ecryptfs_headers",
 680                 .size = PAGE_CACHE_SIZE,
 681         },
 682         {
 683                 .cache = &ecryptfs_xattr_cache,
 684                 .name = "ecryptfs_xattr_cache",
 685                 .size = PAGE_CACHE_SIZE,
 686         },
 687         {
 688                 .cache = &ecryptfs_key_record_cache,
 689                 .name = "ecryptfs_key_record_cache",
 690                 .size = sizeof(struct ecryptfs_key_record),
 691         },
 692         {
 693                 .cache = &ecryptfs_key_sig_cache,
 694                 .name = "ecryptfs_key_sig_cache",
 695                 .size = sizeof(struct ecryptfs_key_sig),
 696         },
 697         {
 698                 .cache = &ecryptfs_global_auth_tok_cache,
 699                 .name = "ecryptfs_global_auth_tok_cache",
 700                 .size = sizeof(struct ecryptfs_global_auth_tok),
 701         },
 702         {
 703                 .cache = &ecryptfs_key_tfm_cache,
 704                 .name = "ecryptfs_key_tfm_cache",
 705                 .size = sizeof(struct ecryptfs_key_tfm),
 706         },
 707 };
 708
 709 static void ecryptfs_free_kmem_caches(void)
 710 {
 711         int i;
 712
 713         /*
 714          * Make sure all delayed rcu free inodes are flushed before we
 715          * destroy cache.
 716          */
 717         rcu_barrier();
 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 [%u] bytes; "
 809                                 "the page size is [%lu] bytes.\n",
 810                                 ECRYPTFS_DEFAULT_EXTENT_SIZE,
 811                                 (unsigned long)PAGE_CACHE_SIZE);
 812                 goto out;
 813         }
 814         rc = ecryptfs_init_kmem_caches();
 815         if (rc) {
 816                 printk(KERN_ERR
 817                        "Failed to allocate one or more kmem_cache objects\n");
 818                 goto out;
 819         }
 820         rc = do_sysfs_registration();
 821         if (rc) {
 822                 printk(KERN_ERR "sysfs registration failed\n");
 823                 goto out_free_kmem_caches;
 824         }
 825         rc = ecryptfs_init_kthread();
 826         if (rc) {
 827                 printk(KERN_ERR "%s: kthread initialization failed; "
 828                        "rc = [%d]\n", __func__, rc);
 829                 goto out_do_sysfs_unregistration;
 830         }
 831         rc = ecryptfs_init_messaging();
 832         if (rc) {
 833                 printk(KERN_ERR "Failure occurred while attempting to "
 834                                 "initialize the communications channel to "
 835                                 "ecryptfsd\n");
 836                 goto out_destroy_kthread;
 837         }
 838         rc = ecryptfs_init_crypto();
 839         if (rc) {
 840                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
 841                        "rc = [%d]\n", rc);
 842                 goto out_release_messaging;
 843         }
 844         rc = register_filesystem(&ecryptfs_fs_type);
 845         if (rc) {
 846                 printk(KERN_ERR "Failed to register filesystem\n");
 847                 goto out_destroy_crypto;
 848         }
 849         if (ecryptfs_verbosity > 0)
 850                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 851                         "will be written to the syslog!\n", ecryptfs_verbosity);
 852
 853         goto out;
 854 out_destroy_crypto:
 855         ecryptfs_destroy_crypto();
 856 out_release_messaging:
 857         ecryptfs_release_messaging();
 858 out_destroy_kthread:
 859         ecryptfs_destroy_kthread();
 860 out_do_sysfs_unregistration:
 861         do_sysfs_unregistration();
 862 out_free_kmem_caches:
 863         ecryptfs_free_kmem_caches();
 864 out:
 865         return rc;
 866 }
 867
 868 static void __exit ecryptfs_exit(void)
 869 {
 870         int rc;
 871
 872         rc = ecryptfs_destroy_crypto();
 873         if (rc)
 874                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 875                        "rc = [%d]\n", rc);
 876         ecryptfs_release_messaging();
 877         ecryptfs_destroy_kthread();
 878         do_sysfs_unregistration();
 879         unregister_filesystem(&ecryptfs_fs_type);
 880         ecryptfs_free_kmem_caches();
 881 }
 882
 883 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 884 MODULE_DESCRIPTION("eCryptfs");
 885
 886 MODULE_LICENSE("GPL");
 887
 888 module_init(ecryptfs_init)
 889 module_exit(ecryptfs_exit)