linux/fs/ecryptfs/main.c
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   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 */
  45int ecryptfs_verbosity = 0;
  46
  47module_param(ecryptfs_verbosity, int, 0);
  48MODULE_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 */
  55unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
  56
  57module_param(ecryptfs_message_buf_len, uint, 0);
  58MODULE_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 */
  67signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
  68
  69module_param(ecryptfs_message_wait_timeout, long, 0);
  70MODULE_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 */
  80unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
  81
  82module_param(ecryptfs_number_of_users, uint, 0);
  83MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
  84                 "concurrent users of eCryptfs");
  85
  86void __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 */
 119static 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
 138int 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
 158void 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                filemap_write_and_wait(inode->i_mapping);
 166                fput(inode_info->lower_file);
 167                inode_info->lower_file = NULL;
 168                mutex_unlock(&inode_info->lower_file_mutex);
 169        }
 170}
 171
 172enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
 173       ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
 174       ecryptfs_opt_ecryptfs_key_bytes,
 175       ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
 176       ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
 177       ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
 178       ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
 179       ecryptfs_opt_check_dev_ruid,
 180       ecryptfs_opt_err };
 181
 182static const match_table_t tokens = {
 183        {ecryptfs_opt_sig, "sig=%s"},
 184        {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 185        {ecryptfs_opt_cipher, "cipher=%s"},
 186        {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
 187        {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
 188        {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
 189        {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
 190        {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
 191        {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
 192        {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
 193        {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
 194        {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
 195        {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
 196        {ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
 197        {ecryptfs_opt_err, NULL}
 198};
 199
 200static int ecryptfs_init_global_auth_toks(
 201        struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 202{
 203        struct ecryptfs_global_auth_tok *global_auth_tok;
 204        struct ecryptfs_auth_tok *auth_tok;
 205        int rc = 0;
 206
 207        list_for_each_entry(global_auth_tok,
 208                            &mount_crypt_stat->global_auth_tok_list,
 209                            mount_crypt_stat_list) {
 210                rc = ecryptfs_keyring_auth_tok_for_sig(
 211                        &global_auth_tok->global_auth_tok_key, &auth_tok,
 212                        global_auth_tok->sig);
 213                if (rc) {
 214                        printk(KERN_ERR "Could not find valid key in user "
 215                               "session keyring for sig specified in mount "
 216                               "option: [%s]\n", global_auth_tok->sig);
 217                        global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 218                        goto out;
 219                } else {
 220                        global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
 221                        up_write(&(global_auth_tok->global_auth_tok_key)->sem);
 222                }
 223        }
 224out:
 225        return rc;
 226}
 227
 228static void ecryptfs_init_mount_crypt_stat(
 229        struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 230{
 231        memset((void *)mount_crypt_stat, 0,
 232               sizeof(struct ecryptfs_mount_crypt_stat));
 233        INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
 234        mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
 235        mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
 236}
 237
 238/**
 239 * ecryptfs_parse_options
 240 * @sb: The ecryptfs super block
 241 * @options: The options passed to the kernel
 242 * @check_ruid: set to 1 if device uid should be checked against the ruid
 243 *
 244 * Parse mount options:
 245 * debug=N         - ecryptfs_verbosity level for debug output
 246 * sig=XXX         - description(signature) of the key to use
 247 *
 248 * Returns the dentry object of the lower-level (lower/interposed)
 249 * directory; We want to mount our stackable file system on top of
 250 * that lower directory.
 251 *
 252 * The signature of the key to use must be the description of a key
 253 * already in the keyring. Mounting will fail if the key can not be
 254 * found.
 255 *
 256 * Returns zero on success; non-zero on error
 257 */
 258static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
 259                                  uid_t *check_ruid)
 260{
 261        char *p;
 262        int rc = 0;
 263        int sig_set = 0;
 264        int cipher_name_set = 0;
 265        int fn_cipher_name_set = 0;
 266        int cipher_key_bytes;
 267        int cipher_key_bytes_set = 0;
 268        int fn_cipher_key_bytes;
 269        int fn_cipher_key_bytes_set = 0;
 270        struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 271                &sbi->mount_crypt_stat;
 272        substring_t args[MAX_OPT_ARGS];
 273        int token;
 274        char *sig_src;
 275        char *cipher_name_dst;
 276        char *cipher_name_src;
 277        char *fn_cipher_name_dst;
 278        char *fn_cipher_name_src;
 279        char *fnek_dst;
 280        char *fnek_src;
 281        char *cipher_key_bytes_src;
 282        char *fn_cipher_key_bytes_src;
 283        u8 cipher_code;
 284
 285        *check_ruid = 0;
 286
 287        if (!options) {
 288                rc = -EINVAL;
 289                goto out;
 290        }
 291        ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
 292        while ((p = strsep(&options, ",")) != NULL) {
 293                if (!*p)
 294                        continue;
 295                token = match_token(p, tokens, args);
 296                switch (token) {
 297                case ecryptfs_opt_sig:
 298                case ecryptfs_opt_ecryptfs_sig:
 299                        sig_src = args[0].from;
 300                        rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
 301                                                          sig_src, 0);
 302                        if (rc) {
 303                                printk(KERN_ERR "Error attempting to register "
 304                                       "global sig; rc = [%d]\n", rc);
 305                                goto out;
 306                        }
 307                        sig_set = 1;
 308                        break;
 309                case ecryptfs_opt_cipher:
 310                case ecryptfs_opt_ecryptfs_cipher:
 311                        cipher_name_src = args[0].from;
 312                        cipher_name_dst =
 313                                mount_crypt_stat->
 314                                global_default_cipher_name;
 315                        strncpy(cipher_name_dst, cipher_name_src,
 316                                ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 317                        cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 318                        cipher_name_set = 1;
 319                        break;
 320                case ecryptfs_opt_ecryptfs_key_bytes:
 321                        cipher_key_bytes_src = args[0].from;
 322                        cipher_key_bytes =
 323                                (int)simple_strtol(cipher_key_bytes_src,
 324                                                   &cipher_key_bytes_src, 0);
 325                        mount_crypt_stat->global_default_cipher_key_size =
 326                                cipher_key_bytes;
 327                        cipher_key_bytes_set = 1;
 328                        break;
 329                case ecryptfs_opt_passthrough:
 330                        mount_crypt_stat->flags |=
 331                                ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 332                        break;
 333                case ecryptfs_opt_xattr_metadata:
 334                        mount_crypt_stat->flags |=
 335                                ECRYPTFS_XATTR_METADATA_ENABLED;
 336                        break;
 337                case ecryptfs_opt_encrypted_view:
 338                        mount_crypt_stat->flags |=
 339                                ECRYPTFS_XATTR_METADATA_ENABLED;
 340                        mount_crypt_stat->flags |=
 341                                ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 342                        break;
 343                case ecryptfs_opt_fnek_sig:
 344                        fnek_src = args[0].from;
 345                        fnek_dst =
 346                                mount_crypt_stat->global_default_fnek_sig;
 347                        strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
 348                        mount_crypt_stat->global_default_fnek_sig[
 349                                ECRYPTFS_SIG_SIZE_HEX] = '\0';
 350                        rc = ecryptfs_add_global_auth_tok(
 351                                mount_crypt_stat,
 352                                mount_crypt_stat->global_default_fnek_sig,
 353                                ECRYPTFS_AUTH_TOK_FNEK);
 354                        if (rc) {
 355                                printk(KERN_ERR "Error attempting to register "
 356                                       "global fnek sig [%s]; rc = [%d]\n",
 357                                       mount_crypt_stat->global_default_fnek_sig,
 358                                       rc);
 359                                goto out;
 360                        }
 361                        mount_crypt_stat->flags |=
 362                                (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 363                                 | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 364                        break;
 365                case ecryptfs_opt_fn_cipher:
 366                        fn_cipher_name_src = args[0].from;
 367                        fn_cipher_name_dst =
 368                                mount_crypt_stat->global_default_fn_cipher_name;
 369                        strncpy(fn_cipher_name_dst, fn_cipher_name_src,
 370                                ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 371                        mount_crypt_stat->global_default_fn_cipher_name[
 372                                ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 373                        fn_cipher_name_set = 1;
 374                        break;
 375                case ecryptfs_opt_fn_cipher_key_bytes:
 376                        fn_cipher_key_bytes_src = args[0].from;
 377                        fn_cipher_key_bytes =
 378                                (int)simple_strtol(fn_cipher_key_bytes_src,
 379                                                   &fn_cipher_key_bytes_src, 0);
 380                        mount_crypt_stat->global_default_fn_cipher_key_bytes =
 381                                fn_cipher_key_bytes;
 382                        fn_cipher_key_bytes_set = 1;
 383                        break;
 384                case ecryptfs_opt_unlink_sigs:
 385                        mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
 386                        break;
 387                case ecryptfs_opt_mount_auth_tok_only:
 388                        mount_crypt_stat->flags |=
 389                                ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
 390                        break;
 391                case ecryptfs_opt_check_dev_ruid:
 392                        *check_ruid = 1;
 393                        break;
 394                case ecryptfs_opt_err:
 395                default:
 396                        printk(KERN_WARNING
 397                               "%s: eCryptfs: unrecognized option [%s]\n",
 398                               __func__, p);
 399                }
 400        }
 401        if (!sig_set) {
 402                rc = -EINVAL;
 403                ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
 404                                "auth tok signature as a mount "
 405                                "parameter; see the eCryptfs README\n");
 406                goto out;
 407        }
 408        if (!cipher_name_set) {
 409                int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 410
 411                BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 412                strcpy(mount_crypt_stat->global_default_cipher_name,
 413                       ECRYPTFS_DEFAULT_CIPHER);
 414        }
 415        if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 416            && !fn_cipher_name_set)
 417                strcpy(mount_crypt_stat->global_default_fn_cipher_name,
 418                       mount_crypt_stat->global_default_cipher_name);
 419        if (!cipher_key_bytes_set)
 420                mount_crypt_stat->global_default_cipher_key_size = 0;
 421        if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 422            && !fn_cipher_key_bytes_set)
 423                mount_crypt_stat->global_default_fn_cipher_key_bytes =
 424                        mount_crypt_stat->global_default_cipher_key_size;
 425
 426        cipher_code = ecryptfs_code_for_cipher_string(
 427                mount_crypt_stat->global_default_cipher_name,
 428                mount_crypt_stat->global_default_cipher_key_size);
 429        if (!cipher_code) {
 430                ecryptfs_printk(KERN_ERR,
 431                                "eCryptfs doesn't support cipher: %s",
 432                                mount_crypt_stat->global_default_cipher_name);
 433                rc = -EINVAL;
 434                goto out;
 435        }
 436
 437        mutex_lock(&key_tfm_list_mutex);
 438        if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
 439                                 NULL)) {
 440                rc = ecryptfs_add_new_key_tfm(
 441                        NULL, mount_crypt_stat->global_default_cipher_name,
 442                        mount_crypt_stat->global_default_cipher_key_size);
 443                if (rc) {
 444                        printk(KERN_ERR "Error attempting to initialize "
 445                               "cipher with name = [%s] and key size = [%td]; "
 446                               "rc = [%d]\n",
 447                               mount_crypt_stat->global_default_cipher_name,
 448                               mount_crypt_stat->global_default_cipher_key_size,
 449                               rc);
 450                        rc = -EINVAL;
 451                        mutex_unlock(&key_tfm_list_mutex);
 452                        goto out;
 453                }
 454        }
 455        if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 456            && !ecryptfs_tfm_exists(
 457                    mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
 458                rc = ecryptfs_add_new_key_tfm(
 459                        NULL, mount_crypt_stat->global_default_fn_cipher_name,
 460                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
 461                if (rc) {
 462                        printk(KERN_ERR "Error attempting to initialize "
 463                               "cipher with name = [%s] and key size = [%td]; "
 464                               "rc = [%d]\n",
 465                               mount_crypt_stat->global_default_fn_cipher_name,
 466                               mount_crypt_stat->global_default_fn_cipher_key_bytes,
 467                               rc);
 468                        rc = -EINVAL;
 469                        mutex_unlock(&key_tfm_list_mutex);
 470                        goto out;
 471                }
 472        }
 473        mutex_unlock(&key_tfm_list_mutex);
 474        rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
 475        if (rc)
 476                printk(KERN_WARNING "One or more global auth toks could not "
 477                       "properly register; rc = [%d]\n", rc);
 478out:
 479        return rc;
 480}
 481
 482struct kmem_cache *ecryptfs_sb_info_cache;
 483static struct file_system_type ecryptfs_fs_type;
 484
 485/**
 486 * ecryptfs_get_sb
 487 * @fs_type
 488 * @flags
 489 * @dev_name: The path to mount over
 490 * @raw_data: The options passed into the kernel
 491 */
 492static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
 493                        const char *dev_name, void *raw_data)
 494{
 495        struct super_block *s;
 496        struct ecryptfs_sb_info *sbi;
 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
 516        s = sget(fs_type, NULL, set_anon_super, flags, NULL);
 517        if (IS_ERR(s)) {
 518                rc = PTR_ERR(s);
 519                goto out;
 520        }
 521
 522        rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY);
 523        if (rc)
 524                goto out1;
 525
 526        ecryptfs_set_superblock_private(s, sbi);
 527        s->s_bdi = &sbi->bdi;
 528
 529        /* ->kill_sb() will take care of sbi after that point */
 530        sbi = NULL;
 531        s->s_op = &ecryptfs_sops;
 532        s->s_d_op = &ecryptfs_dops;
 533
 534        err = "Reading sb failed";
 535        rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 536        if (rc) {
 537                ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
 538                goto out1;
 539        }
 540        if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
 541                rc = -EINVAL;
 542                printk(KERN_ERR "Mount on filesystem of type "
 543                        "eCryptfs explicitly disallowed due to "
 544                        "known incompatibilities\n");
 545                goto out_free;
 546        }
 547
 548        if (check_ruid && !uid_eq(path.dentry->d_inode->i_uid, current_uid())) {
 549                rc = -EPERM;
 550                printk(KERN_ERR "Mount of device (uid: %d) not owned by "
 551                       "requested user (uid: %d)\n",
 552                        i_uid_read(path.dentry->d_inode),
 553                        from_kuid(&init_user_ns, current_uid()));
 554                goto out_free;
 555        }
 556
 557        ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
 558
 559        /**
 560         * Set the POSIX ACL flag based on whether they're enabled in the lower
 561         * mount. Force a read-only eCryptfs mount if the lower mount is ro.
 562         * Allow a ro eCryptfs mount even when the lower mount is rw.
 563         */
 564        s->s_flags = flags & ~MS_POSIXACL;
 565        s->s_flags |= path.dentry->d_sb->s_flags & (MS_RDONLY | MS_POSIXACL);
 566
 567        s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 568        s->s_blocksize = path.dentry->d_sb->s_blocksize;
 569        s->s_magic = ECRYPTFS_SUPER_MAGIC;
 570
 571        inode = ecryptfs_get_inode(path.dentry->d_inode, s);
 572        rc = PTR_ERR(inode);
 573        if (IS_ERR(inode))
 574                goto out_free;
 575
 576        s->s_root = d_make_root(inode);
 577        if (!s->s_root) {
 578                rc = -ENOMEM;
 579                goto out_free;
 580        }
 581
 582        rc = -ENOMEM;
 583        root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 584        if (!root_info)
 585                goto out_free;
 586
 587        /* ->kill_sb() will take care of root_info */
 588        ecryptfs_set_dentry_private(s->s_root, root_info);
 589        ecryptfs_set_dentry_lower(s->s_root, path.dentry);
 590        ecryptfs_set_dentry_lower_mnt(s->s_root, path.mnt);
 591
 592        s->s_flags |= MS_ACTIVE;
 593        return dget(s->s_root);
 594
 595out_free:
 596        path_put(&path);
 597out1:
 598        deactivate_locked_super(s);
 599out:
 600        if (sbi) {
 601                ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
 602                kmem_cache_free(ecryptfs_sb_info_cache, sbi);
 603        }
 604        printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
 605        return ERR_PTR(rc);
 606}
 607
 608/**
 609 * ecryptfs_kill_block_super
 610 * @sb: The ecryptfs super block
 611 *
 612 * Used to bring the superblock down and free the private data.
 613 */
 614static void ecryptfs_kill_block_super(struct super_block *sb)
 615{
 616        struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
 617        kill_anon_super(sb);
 618        if (!sb_info)
 619                return;
 620        ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
 621        bdi_destroy(&sb_info->bdi);
 622        kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
 623}
 624
 625static struct file_system_type ecryptfs_fs_type = {
 626        .owner = THIS_MODULE,
 627        .name = "ecryptfs",
 628        .mount = ecryptfs_mount,
 629        .kill_sb = ecryptfs_kill_block_super,
 630        .fs_flags = 0
 631};
 632
 633/**
 634 * inode_info_init_once
 635 *
 636 * Initializes the ecryptfs_inode_info_cache when it is created
 637 */
 638static void
 639inode_info_init_once(void *vptr)
 640{
 641        struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 642
 643        inode_init_once(&ei->vfs_inode);
 644}
 645
 646static struct ecryptfs_cache_info {
 647        struct kmem_cache **cache;
 648        const char *name;
 649        size_t size;
 650        void (*ctor)(void *obj);
 651} ecryptfs_cache_infos[] = {
 652        {
 653                .cache = &ecryptfs_auth_tok_list_item_cache,
 654                .name = "ecryptfs_auth_tok_list_item",
 655                .size = sizeof(struct ecryptfs_auth_tok_list_item),
 656        },
 657        {
 658                .cache = &ecryptfs_file_info_cache,
 659                .name = "ecryptfs_file_cache",
 660                .size = sizeof(struct ecryptfs_file_info),
 661        },
 662        {
 663                .cache = &ecryptfs_dentry_info_cache,
 664                .name = "ecryptfs_dentry_info_cache",
 665                .size = sizeof(struct ecryptfs_dentry_info),
 666        },
 667        {
 668                .cache = &ecryptfs_inode_info_cache,
 669                .name = "ecryptfs_inode_cache",
 670                .size = sizeof(struct ecryptfs_inode_info),
 671                .ctor = inode_info_init_once,
 672        },
 673        {
 674                .cache = &ecryptfs_sb_info_cache,
 675                .name = "ecryptfs_sb_cache",
 676                .size = sizeof(struct ecryptfs_sb_info),
 677        },
 678        {
 679                .cache = &ecryptfs_header_cache,
 680                .name = "ecryptfs_headers",
 681                .size = PAGE_CACHE_SIZE,
 682        },
 683        {
 684                .cache = &ecryptfs_xattr_cache,
 685                .name = "ecryptfs_xattr_cache",
 686                .size = PAGE_CACHE_SIZE,
 687        },
 688        {
 689                .cache = &ecryptfs_key_record_cache,
 690                .name = "ecryptfs_key_record_cache",
 691                .size = sizeof(struct ecryptfs_key_record),
 692        },
 693        {
 694                .cache = &ecryptfs_key_sig_cache,
 695                .name = "ecryptfs_key_sig_cache",
 696                .size = sizeof(struct ecryptfs_key_sig),
 697        },
 698        {
 699                .cache = &ecryptfs_global_auth_tok_cache,
 700                .name = "ecryptfs_global_auth_tok_cache",
 701                .size = sizeof(struct ecryptfs_global_auth_tok),
 702        },
 703        {
 704                .cache = &ecryptfs_key_tfm_cache,
 705                .name = "ecryptfs_key_tfm_cache",
 706                .size = sizeof(struct ecryptfs_key_tfm),
 707        },
 708};
 709
 710static void ecryptfs_free_kmem_caches(void)
 711{
 712        int i;
 713
 714        /*
 715         * Make sure all delayed rcu free inodes are flushed before we
 716         * destroy cache.
 717         */
 718        rcu_barrier();
 719
 720        for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 721                struct ecryptfs_cache_info *info;
 722
 723                info = &ecryptfs_cache_infos[i];
 724                if (*(info->cache))
 725                        kmem_cache_destroy(*(info->cache));
 726        }
 727}
 728
 729/**
 730 * ecryptfs_init_kmem_caches
 731 *
 732 * Returns zero on success; non-zero otherwise
 733 */
 734static int ecryptfs_init_kmem_caches(void)
 735{
 736        int i;
 737
 738        for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 739                struct ecryptfs_cache_info *info;
 740
 741                info = &ecryptfs_cache_infos[i];
 742                *(info->cache) = kmem_cache_create(info->name, info->size,
 743                                0, SLAB_HWCACHE_ALIGN, info->ctor);
 744                if (!*(info->cache)) {
 745                        ecryptfs_free_kmem_caches();
 746                        ecryptfs_printk(KERN_WARNING, "%s: "
 747                                        "kmem_cache_create failed\n",
 748                                        info->name);
 749                        return -ENOMEM;
 750                }
 751        }
 752        return 0;
 753}
 754
 755static struct kobject *ecryptfs_kobj;
 756
 757static ssize_t version_show(struct kobject *kobj,
 758                            struct kobj_attribute *attr, char *buff)
 759{
 760        return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 761}
 762
 763static struct kobj_attribute version_attr = __ATTR_RO(version);
 764
 765static struct attribute *attributes[] = {
 766        &version_attr.attr,
 767        NULL,
 768};
 769
 770static struct attribute_group attr_group = {
 771        .attrs = attributes,
 772};
 773
 774static int do_sysfs_registration(void)
 775{
 776        int rc;
 777
 778        ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 779        if (!ecryptfs_kobj) {
 780                printk(KERN_ERR "Unable to create ecryptfs kset\n");
 781                rc = -ENOMEM;
 782                goto out;
 783        }
 784        rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 785        if (rc) {
 786                printk(KERN_ERR
 787                       "Unable to create ecryptfs version attributes\n");
 788                kobject_put(ecryptfs_kobj);
 789        }
 790out:
 791        return rc;
 792}
 793
 794static void do_sysfs_unregistration(void)
 795{
 796        sysfs_remove_group(ecryptfs_kobj, &attr_group);
 797        kobject_put(ecryptfs_kobj);
 798}
 799
 800static int __init ecryptfs_init(void)
 801{
 802        int rc;
 803
 804        if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
 805                rc = -EINVAL;
 806                ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 807                                "larger than the host's page size, and so "
 808                                "eCryptfs cannot run on this system. The "
 809                                "default eCryptfs extent size is [%u] bytes; "
 810                                "the page size is [%lu] bytes.\n",
 811                                ECRYPTFS_DEFAULT_EXTENT_SIZE,
 812                                (unsigned long)PAGE_CACHE_SIZE);
 813                goto out;
 814        }
 815        rc = ecryptfs_init_kmem_caches();
 816        if (rc) {
 817                printk(KERN_ERR
 818                       "Failed to allocate one or more kmem_cache objects\n");
 819                goto out;
 820        }
 821        rc = do_sysfs_registration();
 822        if (rc) {
 823                printk(KERN_ERR "sysfs registration failed\n");
 824                goto out_free_kmem_caches;
 825        }
 826        rc = ecryptfs_init_kthread();
 827        if (rc) {
 828                printk(KERN_ERR "%s: kthread initialization failed; "
 829                       "rc = [%d]\n", __func__, rc);
 830                goto out_do_sysfs_unregistration;
 831        }
 832        rc = ecryptfs_init_messaging();
 833        if (rc) {
 834                printk(KERN_ERR "Failure occurred while attempting to "
 835                                "initialize the communications channel to "
 836                                "ecryptfsd\n");
 837                goto out_destroy_kthread;
 838        }
 839        rc = ecryptfs_init_crypto();
 840        if (rc) {
 841                printk(KERN_ERR "Failure whilst attempting to init crypto; "
 842                       "rc = [%d]\n", rc);
 843                goto out_release_messaging;
 844        }
 845        rc = register_filesystem(&ecryptfs_fs_type);
 846        if (rc) {
 847                printk(KERN_ERR "Failed to register filesystem\n");
 848                goto out_destroy_crypto;
 849        }
 850        if (ecryptfs_verbosity > 0)
 851                printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 852                        "will be written to the syslog!\n", ecryptfs_verbosity);
 853
 854        goto out;
 855out_destroy_crypto:
 856        ecryptfs_destroy_crypto();
 857out_release_messaging:
 858        ecryptfs_release_messaging();
 859out_destroy_kthread:
 860        ecryptfs_destroy_kthread();
 861out_do_sysfs_unregistration:
 862        do_sysfs_unregistration();
 863out_free_kmem_caches:
 864        ecryptfs_free_kmem_caches();
 865out:
 866        return rc;
 867}
 868
 869static void __exit ecryptfs_exit(void)
 870{
 871        int rc;
 872
 873        rc = ecryptfs_destroy_crypto();
 874        if (rc)
 875                printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 876                       "rc = [%d]\n", rc);
 877        ecryptfs_release_messaging();
 878        ecryptfs_destroy_kthread();
 879        do_sysfs_unregistration();
 880        unregister_filesystem(&ecryptfs_fs_type);
 881        ecryptfs_free_kmem_caches();
 882}
 883
 884MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 885MODULE_DESCRIPTION("eCryptfs");
 886
 887MODULE_LICENSE("GPL");
 888
 889module_init(ecryptfs_init)
 890module_exit(ecryptfs_exit)
 891
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