fs/ecryptfs/main.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * eCryptfs: Linux filesystem encryption layer
   4  *
   5  * Copyright (C) 1997-2003 Erez Zadok
   6  * Copyright (C) 2001-2003 Stony Brook University
   7  * Copyright (C) 2004-2007 International Business Machines Corp.
   8  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
   9  *              Michael C. Thompson <mcthomps@us.ibm.com>
  10  *              Tyler Hicks <code@tyhicks.com>
  11  */
  12
  13 #include <linux/dcache.h>
  14 #include <linux/file.h>
  15 #include <linux/module.h>
  16 #include <linux/namei.h>
  17 #include <linux/skbuff.h>
  18 #include <linux/mount.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/key.h>
  21 #include <linux/parser.h>
  22 #include <linux/fs_stack.h>
  23 #include <linux/slab.h>
  24 #include <linux/magic.h>
  25 #include "ecryptfs_kernel.h"
  26
  27 /*
  28  * Module parameter that defines the ecryptfs_verbosity level.
  29  */
  30 int ecryptfs_verbosity = 0;
  31
  32 module_param(ecryptfs_verbosity, int, 0);
  33 MODULE_PARM_DESC(ecryptfs_verbosity,
  34                  "Initial verbosity level (0 or 1; defaults to "
  35                  "0, which is Quiet)");
  36
  37 /*
  38  * Module parameter that defines the number of message buffer elements
  39  */
  40 unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
  41
  42 module_param(ecryptfs_message_buf_len, uint, 0);
  43 MODULE_PARM_DESC(ecryptfs_message_buf_len,
  44                  "Number of message buffer elements");
  45
  46 /*
  47  * Module parameter that defines the maximum guaranteed amount of time to wait
  48  * for a response from ecryptfsd.  The actual sleep time will be, more than
  49  * likely, a small amount greater than this specified value, but only less if
  50  * the message successfully arrives.
  51  */
  52 signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
  53
  54 module_param(ecryptfs_message_wait_timeout, long, 0);
  55 MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
  56                  "Maximum number of seconds that an operation will "
  57                  "sleep while waiting for a message response from "
  58                  "userspace");
  59
  60 /*
  61  * Module parameter that is an estimate of the maximum number of users
  62  * that will be concurrently using eCryptfs. Set this to the right
  63  * value to balance performance and memory use.
  64  */
  65 unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
  66
  67 module_param(ecryptfs_number_of_users, uint, 0);
  68 MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
  69                  "concurrent users of eCryptfs");
  70
  71 void __ecryptfs_printk(const char *fmt, ...)
  72 {
  73         va_list args;
  74         va_start(args, fmt);
  75         if (fmt[1] == '7') { /* KERN_DEBUG */
  76                 if (ecryptfs_verbosity >= 1)
  77                         vprintk(fmt, args);
  78         } else
  79                 vprintk(fmt, args);
  80         va_end(args);
  81 }
  82
  83 /*
  84  * ecryptfs_init_lower_file
  85  * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
  86  *                   the lower dentry and the lower mount set
  87  *
  88  * eCryptfs only ever keeps a single open file for every lower
  89  * inode. All I/O operations to the lower inode occur through that
  90  * file. When the first eCryptfs dentry that interposes with the first
  91  * lower dentry for that inode is created, this function creates the
  92  * lower file struct and associates it with the eCryptfs
  93  * inode. When all eCryptfs files associated with the inode are released, the
  94  * file is closed.
  95  *
  96  * The lower file will be opened with read/write permissions, if
  97  * possible. Otherwise, it is opened read-only.
  98  *
  99  * This function does nothing if a lower file is already
 100  * associated with the eCryptfs inode.
 101  *
 102  * Returns zero on success; non-zero otherwise
 103  */
 104 static int ecryptfs_init_lower_file(struct dentry *dentry,
 105                                     struct file **lower_file)
 106 {
 107         const struct cred *cred = current_cred();
 108         struct path *path = ecryptfs_dentry_to_lower_path(dentry);
 109         int rc;
 110
 111         rc = ecryptfs_privileged_open(lower_file, path->dentry, path->mnt,
 112                                       cred);
 113         if (rc) {
 114                 printk(KERN_ERR "Error opening lower file "
 115                        "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
 116                        "rc = [%d]\n", path->dentry, path->mnt, rc);
 117                 (*lower_file) = NULL;
 118         }
 119         return rc;
 120 }
 121
 122 int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
 123 {
 124         struct ecryptfs_inode_info *inode_info;
 125         int count, rc = 0;
 126
 127         inode_info = ecryptfs_inode_to_private(inode);
 128         mutex_lock(&inode_info->lower_file_mutex);
 129         count = atomic_inc_return(&inode_info->lower_file_count);
 130         if (WARN_ON_ONCE(count < 1))
 131                 rc = -EINVAL;
 132         else if (count == 1) {
 133                 rc = ecryptfs_init_lower_file(dentry,
 134                                               &inode_info->lower_file);
 135                 if (rc)
 136                         atomic_set(&inode_info->lower_file_count, 0);
 137         }
 138         mutex_unlock(&inode_info->lower_file_mutex);
 139         return rc;
 140 }
 141
 142 void ecryptfs_put_lower_file(struct inode *inode)
 143 {
 144         struct ecryptfs_inode_info *inode_info;
 145
 146         inode_info = ecryptfs_inode_to_private(inode);
 147         if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
 148                                       &inode_info->lower_file_mutex)) {
 149                 filemap_write_and_wait(inode->i_mapping);
 150                 fput(inode_info->lower_file);
 151                 inode_info->lower_file = NULL;
 152                 mutex_unlock(&inode_info->lower_file_mutex);
 153         }
 154 }
 155
 156 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
 157        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
 158        ecryptfs_opt_ecryptfs_key_bytes,
 159        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
 160        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
 161        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
 162        ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
 163        ecryptfs_opt_check_dev_ruid,
 164        ecryptfs_opt_err };
 165
 166 static const match_table_t tokens = {
 167         {ecryptfs_opt_sig, "sig=%s"},
 168         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 169         {ecryptfs_opt_cipher, "cipher=%s"},
 170         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
 171         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
 172         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
 173         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
 174         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
 175         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
 176         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
 177         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
 178         {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
 179         {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
 180         {ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
 181         {ecryptfs_opt_err, NULL}
 182 };
 183
 184 static int ecryptfs_init_global_auth_toks(
 185         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 186 {
 187         struct ecryptfs_global_auth_tok *global_auth_tok;
 188         struct ecryptfs_auth_tok *auth_tok;
 189         int rc = 0;
 190
 191         list_for_each_entry(global_auth_tok,
 192                             &mount_crypt_stat->global_auth_tok_list,
 193                             mount_crypt_stat_list) {
 194                 rc = ecryptfs_keyring_auth_tok_for_sig(
 195                         &global_auth_tok->global_auth_tok_key, &auth_tok,
 196                         global_auth_tok->sig);
 197                 if (rc) {
 198                         printk(KERN_ERR "Could not find valid key in user "
 199                                "session keyring for sig specified in mount "
 200                                "option: [%s]\n", global_auth_tok->sig);
 201                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 202                         goto out;
 203                 } else {
 204                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
 205                         up_write(&(global_auth_tok->global_auth_tok_key)->sem);
 206                 }
 207         }
 208 out:
 209         return rc;
 210 }
 211
 212 static void ecryptfs_init_mount_crypt_stat(
 213         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 214 {
 215         memset((void *)mount_crypt_stat, 0,
 216                sizeof(struct ecryptfs_mount_crypt_stat));
 217         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
 218         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
 219         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
 220 }
 221
 222 /**
 223  * ecryptfs_parse_options
 224  * @sbi: The ecryptfs super block
 225  * @options: The options passed to the kernel
 226  * @check_ruid: set to 1 if device uid should be checked against the ruid
 227  *
 228  * Parse mount options:
 229  * debug=N         - ecryptfs_verbosity level for debug output
 230  * sig=XXX         - description(signature) of the key to use
 231  *
 232  * Returns the dentry object of the lower-level (lower/interposed)
 233  * directory; We want to mount our stackable file system on top of
 234  * that lower directory.
 235  *
 236  * The signature of the key to use must be the description of a key
 237  * already in the keyring. Mounting will fail if the key can not be
 238  * found.
 239  *
 240  * Returns zero on success; non-zero on error
 241  */
 242 static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
 243                                   uid_t *check_ruid)
 244 {
 245         char *p;
 246         int rc = 0;
 247         int sig_set = 0;
 248         int cipher_name_set = 0;
 249         int fn_cipher_name_set = 0;
 250         int cipher_key_bytes;
 251         int cipher_key_bytes_set = 0;
 252         int fn_cipher_key_bytes;
 253         int fn_cipher_key_bytes_set = 0;
 254         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 255                 &sbi->mount_crypt_stat;
 256         substring_t args[MAX_OPT_ARGS];
 257         int token;
 258         char *sig_src;
 259         char *cipher_name_dst;
 260         char *cipher_name_src;
 261         char *fn_cipher_name_dst;
 262         char *fn_cipher_name_src;
 263         char *fnek_dst;
 264         char *fnek_src;
 265         char *cipher_key_bytes_src;
 266         char *fn_cipher_key_bytes_src;
 267         u8 cipher_code;
 268
 269         *check_ruid = 0;
 270
 271         if (!options) {
 272                 rc = -EINVAL;
 273                 goto out;
 274         }
 275         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
 276         while ((p = strsep(&options, ",")) != NULL) {
 277                 if (!*p)
 278                         continue;
 279                 token = match_token(p, tokens, args);
 280                 switch (token) {
 281                 case ecryptfs_opt_sig:
 282                 case ecryptfs_opt_ecryptfs_sig:
 283                         sig_src = args[0].from;
 284                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
 285                                                           sig_src, 0);
 286                         if (rc) {
 287                                 printk(KERN_ERR "Error attempting to register "
 288                                        "global sig; rc = [%d]\n", rc);
 289                                 goto out;
 290                         }
 291                         sig_set = 1;
 292                         break;
 293                 case ecryptfs_opt_cipher:
 294                 case ecryptfs_opt_ecryptfs_cipher:
 295                         cipher_name_src = args[0].from;
 296                         cipher_name_dst =
 297                                 mount_crypt_stat->
 298                                 global_default_cipher_name;
 299                         strncpy(cipher_name_dst, cipher_name_src,
 300                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 301                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 302                         cipher_name_set = 1;
 303                         break;
 304                 case ecryptfs_opt_ecryptfs_key_bytes:
 305                         cipher_key_bytes_src = args[0].from;
 306                         cipher_key_bytes =
 307                                 (int)simple_strtol(cipher_key_bytes_src,
 308                                                    &cipher_key_bytes_src, 0);
 309                         mount_crypt_stat->global_default_cipher_key_size =
 310                                 cipher_key_bytes;
 311                         cipher_key_bytes_set = 1;
 312                         break;
 313                 case ecryptfs_opt_passthrough:
 314                         mount_crypt_stat->flags |=
 315                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 316                         break;
 317                 case ecryptfs_opt_xattr_metadata:
 318                         mount_crypt_stat->flags |=
 319                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 320                         break;
 321                 case ecryptfs_opt_encrypted_view:
 322                         mount_crypt_stat->flags |=
 323                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 324                         mount_crypt_stat->flags |=
 325                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 326                         break;
 327                 case ecryptfs_opt_fnek_sig:
 328                         fnek_src = args[0].from;
 329                         fnek_dst =
 330                                 mount_crypt_stat->global_default_fnek_sig;
 331                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
 332                         mount_crypt_stat->global_default_fnek_sig[
 333                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
 334                         rc = ecryptfs_add_global_auth_tok(
 335                                 mount_crypt_stat,
 336                                 mount_crypt_stat->global_default_fnek_sig,
 337                                 ECRYPTFS_AUTH_TOK_FNEK);
 338                         if (rc) {
 339                                 printk(KERN_ERR "Error attempting to register "
 340                                        "global fnek sig [%s]; rc = [%d]\n",
 341                                        mount_crypt_stat->global_default_fnek_sig,
 342                                        rc);
 343                                 goto out;
 344                         }
 345                         mount_crypt_stat->flags |=
 346                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 347                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 348                         break;
 349                 case ecryptfs_opt_fn_cipher:
 350                         fn_cipher_name_src = args[0].from;
 351                         fn_cipher_name_dst =
 352                                 mount_crypt_stat->global_default_fn_cipher_name;
 353                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
 354                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 355                         mount_crypt_stat->global_default_fn_cipher_name[
 356                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 357                         fn_cipher_name_set = 1;
 358                         break;
 359                 case ecryptfs_opt_fn_cipher_key_bytes:
 360                         fn_cipher_key_bytes_src = args[0].from;
 361                         fn_cipher_key_bytes =
 362                                 (int)simple_strtol(fn_cipher_key_bytes_src,
 363                                                    &fn_cipher_key_bytes_src, 0);
 364                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
 365                                 fn_cipher_key_bytes;
 366                         fn_cipher_key_bytes_set = 1;
 367                         break;
 368                 case ecryptfs_opt_unlink_sigs:
 369                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
 370                         break;
 371                 case ecryptfs_opt_mount_auth_tok_only:
 372                         mount_crypt_stat->flags |=
 373                                 ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
 374                         break;
 375                 case ecryptfs_opt_check_dev_ruid:
 376                         *check_ruid = 1;
 377                         break;
 378                 case ecryptfs_opt_err:
 379                 default:
 380                         printk(KERN_WARNING
 381                                "%s: eCryptfs: unrecognized option [%s]\n",
 382                                __func__, p);
 383                 }
 384         }
 385         if (!sig_set) {
 386                 rc = -EINVAL;
 387                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
 388                                 "auth tok signature as a mount "
 389                                 "parameter; see the eCryptfs README\n");
 390                 goto out;
 391         }
 392         if (!cipher_name_set) {
 393                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 394
 395                 BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 396                 strcpy(mount_crypt_stat->global_default_cipher_name,
 397                        ECRYPTFS_DEFAULT_CIPHER);
 398         }
 399         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 400             && !fn_cipher_name_set)
 401                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
 402                        mount_crypt_stat->global_default_cipher_name);
 403         if (!cipher_key_bytes_set)
 404                 mount_crypt_stat->global_default_cipher_key_size = 0;
 405         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 406             && !fn_cipher_key_bytes_set)
 407                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
 408                         mount_crypt_stat->global_default_cipher_key_size;
 409
 410         cipher_code = ecryptfs_code_for_cipher_string(
 411                 mount_crypt_stat->global_default_cipher_name,
 412                 mount_crypt_stat->global_default_cipher_key_size);
 413         if (!cipher_code) {
 414                 ecryptfs_printk(KERN_ERR,
 415                                 "eCryptfs doesn't support cipher: %s\n",
 416                                 mount_crypt_stat->global_default_cipher_name);
 417                 rc = -EINVAL;
 418                 goto out;
 419         }
 420
 421         mutex_lock(&key_tfm_list_mutex);
 422         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
 423                                  NULL)) {
 424                 rc = ecryptfs_add_new_key_tfm(
 425                         NULL, mount_crypt_stat->global_default_cipher_name,
 426                         mount_crypt_stat->global_default_cipher_key_size);
 427                 if (rc) {
 428                         printk(KERN_ERR "Error attempting to initialize "
 429                                "cipher with name = [%s] and key size = [%td]; "
 430                                "rc = [%d]\n",
 431                                mount_crypt_stat->global_default_cipher_name,
 432                                mount_crypt_stat->global_default_cipher_key_size,
 433                                rc);
 434                         rc = -EINVAL;
 435                         mutex_unlock(&key_tfm_list_mutex);
 436                         goto out;
 437                 }
 438         }
 439         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 440             && !ecryptfs_tfm_exists(
 441                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
 442                 rc = ecryptfs_add_new_key_tfm(
 443                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
 444                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
 445                 if (rc) {
 446                         printk(KERN_ERR "Error attempting to initialize "
 447                                "cipher with name = [%s] and key size = [%td]; "
 448                                "rc = [%d]\n",
 449                                mount_crypt_stat->global_default_fn_cipher_name,
 450                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
 451                                rc);
 452                         rc = -EINVAL;
 453                         mutex_unlock(&key_tfm_list_mutex);
 454                         goto out;
 455                 }
 456         }
 457         mutex_unlock(&key_tfm_list_mutex);
 458         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
 459         if (rc)
 460                 printk(KERN_WARNING "One or more global auth toks could not "
 461                        "properly register; rc = [%d]\n", rc);
 462 out:
 463         return rc;
 464 }
 465
 466 struct kmem_cache *ecryptfs_sb_info_cache;
 467 static struct file_system_type ecryptfs_fs_type;
 468
 469 /*
 470  * ecryptfs_mount
 471  * @fs_type: The filesystem type that the superblock should belong to
 472  * @flags: The flags associated with the mount
 473  * @dev_name: The path to mount over
 474  * @raw_data: The options passed into the kernel
 475  */
 476 static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
 477                         const char *dev_name, void *raw_data)
 478 {
 479         struct super_block *s;
 480         struct ecryptfs_sb_info *sbi;
 481         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 482         struct ecryptfs_dentry_info *root_info;
 483         const char *err = "Getting sb failed";
 484         struct inode *inode;
 485         struct path path;
 486         uid_t check_ruid;
 487         int rc;
 488
 489         sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
 490         if (!sbi) {
 491                 rc = -ENOMEM;
 492                 goto out;
 493         }
 494
 495         if (!dev_name) {
 496                 rc = -EINVAL;
 497                 err = "Device name cannot be null";
 498                 goto out;
 499         }
 500
 501         rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
 502         if (rc) {
 503                 err = "Error parsing options";
 504                 goto out;
 505         }
 506         mount_crypt_stat = &sbi->mount_crypt_stat;
 507
 508         s = sget(fs_type, NULL, set_anon_super, flags, NULL);
 509         if (IS_ERR(s)) {
 510                 rc = PTR_ERR(s);
 511                 goto out;
 512         }
 513
 514         rc = super_setup_bdi(s);
 515         if (rc)
 516                 goto out1;
 517
 518         ecryptfs_set_superblock_private(s, sbi);
 519
 520         /* ->kill_sb() will take care of sbi after that point */
 521         sbi = NULL;
 522         s->s_op = &ecryptfs_sops;
 523         s->s_xattr = ecryptfs_xattr_handlers;
 524         s->s_d_op = &ecryptfs_dops;
 525
 526         err = "Reading sb failed";
 527         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 528         if (rc) {
 529                 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
 530                 goto out1;
 531         }
 532         if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
 533                 rc = -EINVAL;
 534                 printk(KERN_ERR "Mount on filesystem of type "
 535                         "eCryptfs explicitly disallowed due to "
 536                         "known incompatibilities\n");
 537                 goto out_free;
 538         }
 539
 540         if (mnt_user_ns(path.mnt) != &init_user_ns) {
 541                 rc = -EINVAL;
 542                 printk(KERN_ERR "Mounting on idmapped mounts currently disallowed\n");
 543                 goto out_free;
 544         }
 545
 546         if (check_ruid && !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) {
 547                 rc = -EPERM;
 548                 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
 549                        "requested user (uid: %d)\n",
 550                         i_uid_read(d_inode(path.dentry)),
 551                         from_kuid(&init_user_ns, current_uid()));
 552                 goto out_free;
 553         }
 554
 555         ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
 556
 557         /**
 558          * Set the POSIX ACL flag based on whether they're enabled in the lower
 559          * mount.
 560          */
 561         s->s_flags = flags & ~SB_POSIXACL;
 562         s->s_flags |= path.dentry->d_sb->s_flags & SB_POSIXACL;
 563
 564         /**
 565          * Force a read-only eCryptfs mount when:
 566          *   1) The lower mount is ro
 567          *   2) The ecryptfs_encrypted_view mount option is specified
 568          */
 569         if (sb_rdonly(path.dentry->d_sb) || mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
 570                 s->s_flags |= SB_RDONLY;
 571
 572         s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 573         s->s_blocksize = path.dentry->d_sb->s_blocksize;
 574         s->s_magic = ECRYPTFS_SUPER_MAGIC;
 575         s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
 576
 577         rc = -EINVAL;
 578         if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
 579                 pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
 580                 goto out_free;
 581         }
 582
 583         inode = ecryptfs_get_inode(d_inode(path.dentry), s);
 584         rc = PTR_ERR(inode);
 585         if (IS_ERR(inode))
 586                 goto out_free;
 587
 588         s->s_root = d_make_root(inode);
 589         if (!s->s_root) {
 590                 rc = -ENOMEM;
 591                 goto out_free;
 592         }
 593
 594         rc = -ENOMEM;
 595         root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 596         if (!root_info)
 597                 goto out_free;
 598
 599         /* ->kill_sb() will take care of root_info */
 600         ecryptfs_set_dentry_private(s->s_root, root_info);
 601         root_info->lower_path = path;
 602
 603         s->s_flags |= SB_ACTIVE;
 604         return dget(s->s_root);
 605
 606 out_free:
 607         path_put(&path);
 608 out1:
 609         deactivate_locked_super(s);
 610 out:
 611         if (sbi) {
 612                 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
 613                 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
 614         }
 615         printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
 616         return ERR_PTR(rc);
 617 }
 618
 619 /**
 620  * ecryptfs_kill_block_super
 621  * @sb: The ecryptfs super block
 622  *
 623  * Used to bring the superblock down and free the private data.
 624  */
 625 static void ecryptfs_kill_block_super(struct super_block *sb)
 626 {
 627         struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
 628         kill_anon_super(sb);
 629         if (!sb_info)
 630                 return;
 631         ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
 632         kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
 633 }
 634
 635 static struct file_system_type ecryptfs_fs_type = {
 636         .owner = THIS_MODULE,
 637         .name = "ecryptfs",
 638         .mount = ecryptfs_mount,
 639         .kill_sb = ecryptfs_kill_block_super,
 640         .fs_flags = 0
 641 };
 642 MODULE_ALIAS_FS("ecryptfs");
 643
 644 /*
 645  * inode_info_init_once
 646  *
 647  * Initializes the ecryptfs_inode_info_cache when it is created
 648  */
 649 static void
 650 inode_info_init_once(void *vptr)
 651 {
 652         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 653
 654         inode_init_once(&ei->vfs_inode);
 655 }
 656
 657 static struct ecryptfs_cache_info {
 658         struct kmem_cache **cache;
 659         const char *name;
 660         size_t size;
 661         slab_flags_t flags;
 662         void (*ctor)(void *obj);
 663 } ecryptfs_cache_infos[] = {
 664         {
 665                 .cache = &ecryptfs_auth_tok_list_item_cache,
 666                 .name = "ecryptfs_auth_tok_list_item",
 667                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 668         },
 669         {
 670                 .cache = &ecryptfs_file_info_cache,
 671                 .name = "ecryptfs_file_cache",
 672                 .size = sizeof(struct ecryptfs_file_info),
 673         },
 674         {
 675                 .cache = &ecryptfs_dentry_info_cache,
 676                 .name = "ecryptfs_dentry_info_cache",
 677                 .size = sizeof(struct ecryptfs_dentry_info),
 678         },
 679         {
 680                 .cache = &ecryptfs_inode_info_cache,
 681                 .name = "ecryptfs_inode_cache",
 682                 .size = sizeof(struct ecryptfs_inode_info),
 683                 .flags = SLAB_ACCOUNT,
 684                 .ctor = inode_info_init_once,
 685         },
 686         {
 687                 .cache = &ecryptfs_sb_info_cache,
 688                 .name = "ecryptfs_sb_cache",
 689                 .size = sizeof(struct ecryptfs_sb_info),
 690         },
 691         {
 692                 .cache = &ecryptfs_header_cache,
 693                 .name = "ecryptfs_headers",
 694                 .size = PAGE_SIZE,
 695         },
 696         {
 697                 .cache = &ecryptfs_xattr_cache,
 698                 .name = "ecryptfs_xattr_cache",
 699                 .size = PAGE_SIZE,
 700         },
 701         {
 702                 .cache = &ecryptfs_key_record_cache,
 703                 .name = "ecryptfs_key_record_cache",
 704                 .size = sizeof(struct ecryptfs_key_record),
 705         },
 706         {
 707                 .cache = &ecryptfs_key_sig_cache,
 708                 .name = "ecryptfs_key_sig_cache",
 709                 .size = sizeof(struct ecryptfs_key_sig),
 710         },
 711         {
 712                 .cache = &ecryptfs_global_auth_tok_cache,
 713                 .name = "ecryptfs_global_auth_tok_cache",
 714                 .size = sizeof(struct ecryptfs_global_auth_tok),
 715         },
 716         {
 717                 .cache = &ecryptfs_key_tfm_cache,
 718                 .name = "ecryptfs_key_tfm_cache",
 719                 .size = sizeof(struct ecryptfs_key_tfm),
 720         },
 721 };
 722
 723 static void ecryptfs_free_kmem_caches(void)
 724 {
 725         int i;
 726
 727         /*
 728          * Make sure all delayed rcu free inodes are flushed before we
 729          * destroy cache.
 730          */
 731         rcu_barrier();
 732
 733         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 734                 struct ecryptfs_cache_info *info;
 735
 736                 info = &ecryptfs_cache_infos[i];
 737                 kmem_cache_destroy(*(info->cache));
 738         }
 739 }
 740
 741 /**
 742  * ecryptfs_init_kmem_caches
 743  *
 744  * Returns zero on success; non-zero otherwise
 745  */
 746 static int ecryptfs_init_kmem_caches(void)
 747 {
 748         int i;
 749
 750         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 751                 struct ecryptfs_cache_info *info;
 752
 753                 info = &ecryptfs_cache_infos[i];
 754                 *(info->cache) = kmem_cache_create(info->name, info->size, 0,
 755                                 SLAB_HWCACHE_ALIGN | info->flags, info->ctor);
 756                 if (!*(info->cache)) {
 757                         ecryptfs_free_kmem_caches();
 758                         ecryptfs_printk(KERN_WARNING, "%s: "
 759                                         "kmem_cache_create failed\n",
 760                                         info->name);
 761                         return -ENOMEM;
 762                 }
 763         }
 764         return 0;
 765 }
 766
 767 static struct kobject *ecryptfs_kobj;
 768
 769 static ssize_t version_show(struct kobject *kobj,
 770                             struct kobj_attribute *attr, char *buff)
 771 {
 772         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 773 }
 774
 775 static struct kobj_attribute version_attr = __ATTR_RO(version);
 776
 777 static struct attribute *attributes[] = {
 778         &version_attr.attr,
 779         NULL,
 780 };
 781
 782 static const struct attribute_group attr_group = {
 783         .attrs = attributes,
 784 };
 785
 786 static int do_sysfs_registration(void)
 787 {
 788         int rc;
 789
 790         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 791         if (!ecryptfs_kobj) {
 792                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
 793                 rc = -ENOMEM;
 794                 goto out;
 795         }
 796         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 797         if (rc) {
 798                 printk(KERN_ERR
 799                        "Unable to create ecryptfs version attributes\n");
 800                 kobject_put(ecryptfs_kobj);
 801         }
 802 out:
 803         return rc;
 804 }
 805
 806 static void do_sysfs_unregistration(void)
 807 {
 808         sysfs_remove_group(ecryptfs_kobj, &attr_group);
 809         kobject_put(ecryptfs_kobj);
 810 }
 811
 812 static int __init ecryptfs_init(void)
 813 {
 814         int rc;
 815
 816         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_SIZE) {
 817                 rc = -EINVAL;
 818                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 819                                 "larger than the host's page size, and so "
 820                                 "eCryptfs cannot run on this system. The "
 821                                 "default eCryptfs extent size is [%u] bytes; "
 822                                 "the page size is [%lu] bytes.\n",
 823                                 ECRYPTFS_DEFAULT_EXTENT_SIZE,
 824                                 (unsigned long)PAGE_SIZE);
 825                 goto out;
 826         }
 827         rc = ecryptfs_init_kmem_caches();
 828         if (rc) {
 829                 printk(KERN_ERR
 830                        "Failed to allocate one or more kmem_cache objects\n");
 831                 goto out;
 832         }
 833         rc = do_sysfs_registration();
 834         if (rc) {
 835                 printk(KERN_ERR "sysfs registration failed\n");
 836                 goto out_free_kmem_caches;
 837         }
 838         rc = ecryptfs_init_kthread();
 839         if (rc) {
 840                 printk(KERN_ERR "%s: kthread initialization failed; "
 841                        "rc = [%d]\n", __func__, rc);
 842                 goto out_do_sysfs_unregistration;
 843         }
 844         rc = ecryptfs_init_messaging();
 845         if (rc) {
 846                 printk(KERN_ERR "Failure occurred while attempting to "
 847                                 "initialize the communications channel to "
 848                                 "ecryptfsd\n");
 849                 goto out_destroy_kthread;
 850         }
 851         rc = ecryptfs_init_crypto();
 852         if (rc) {
 853                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
 854                        "rc = [%d]\n", rc);
 855                 goto out_release_messaging;
 856         }
 857         rc = register_filesystem(&ecryptfs_fs_type);
 858         if (rc) {
 859                 printk(KERN_ERR "Failed to register filesystem\n");
 860                 goto out_destroy_crypto;
 861         }
 862         if (ecryptfs_verbosity > 0)
 863                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 864                         "will be written to the syslog!\n", ecryptfs_verbosity);
 865
 866         goto out;
 867 out_destroy_crypto:
 868         ecryptfs_destroy_crypto();
 869 out_release_messaging:
 870         ecryptfs_release_messaging();
 871 out_destroy_kthread:
 872         ecryptfs_destroy_kthread();
 873 out_do_sysfs_unregistration:
 874         do_sysfs_unregistration();
 875 out_free_kmem_caches:
 876         ecryptfs_free_kmem_caches();
 877 out:
 878         return rc;
 879 }
 880
 881 static void __exit ecryptfs_exit(void)
 882 {
 883         int rc;
 884
 885         rc = ecryptfs_destroy_crypto();
 886         if (rc)
 887                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 888                        "rc = [%d]\n", rc);
 889         ecryptfs_release_messaging();
 890         ecryptfs_destroy_kthread();
 891         do_sysfs_unregistration();
 892         unregister_filesystem(&ecryptfs_fs_type);
 893         ecryptfs_free_kmem_caches();
 894 }
 895
 896 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 897 MODULE_DESCRIPTION("eCryptfs");
 898
 899 MODULE_LICENSE("GPL");
 900
 901 module_init(ecryptfs_init)
 902 module_exit(ecryptfs_exit)