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         const 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_src;
 260         char *fn_cipher_name_src;
 261         char *fnek_src;
 262         char *cipher_key_bytes_src;
 263         char *fn_cipher_key_bytes_src;
 264         u8 cipher_code;
 265
 266         *check_ruid = 0;
 267
 268         if (!options) {
 269                 rc = -EINVAL;
 270                 goto out;
 271         }
 272         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
 273         while ((p = strsep(&options, ",")) != NULL) {
 274                 if (!*p)
 275                         continue;
 276                 token = match_token(p, tokens, args);
 277                 switch (token) {
 278                 case ecryptfs_opt_sig:
 279                 case ecryptfs_opt_ecryptfs_sig:
 280                         sig_src = args[0].from;
 281                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
 282                                                           sig_src, 0);
 283                         if (rc) {
 284                                 printk(KERN_ERR "Error attempting to register "
 285                                        "global sig; rc = [%d]\n", rc);
 286                                 goto out;
 287                         }
 288                         sig_set = 1;
 289                         break;
 290                 case ecryptfs_opt_cipher:
 291                 case ecryptfs_opt_ecryptfs_cipher:
 292                         cipher_name_src = args[0].from;
 293                         strscpy(mount_crypt_stat->global_default_cipher_name,
 294                                 cipher_name_src);
 295                         cipher_name_set = 1;
 296                         break;
 297                 case ecryptfs_opt_ecryptfs_key_bytes:
 298                         cipher_key_bytes_src = args[0].from;
 299                         cipher_key_bytes =
 300                                 (int)simple_strtol(cipher_key_bytes_src,
 301                                                    &cipher_key_bytes_src, 0);
 302                         mount_crypt_stat->global_default_cipher_key_size =
 303                                 cipher_key_bytes;
 304                         cipher_key_bytes_set = 1;
 305                         break;
 306                 case ecryptfs_opt_passthrough:
 307                         mount_crypt_stat->flags |=
 308                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 309                         break;
 310                 case ecryptfs_opt_xattr_metadata:
 311                         mount_crypt_stat->flags |=
 312                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 313                         break;
 314                 case ecryptfs_opt_encrypted_view:
 315                         mount_crypt_stat->flags |=
 316                                 ECRYPTFS_XATTR_METADATA_ENABLED;
 317                         mount_crypt_stat->flags |=
 318                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 319                         break;
 320                 case ecryptfs_opt_fnek_sig:
 321                         fnek_src = args[0].from;
 322                         strscpy(mount_crypt_stat->global_default_fnek_sig,
 323                                 fnek_src);
 324                         rc = ecryptfs_add_global_auth_tok(
 325                                 mount_crypt_stat,
 326                                 mount_crypt_stat->global_default_fnek_sig,
 327                                 ECRYPTFS_AUTH_TOK_FNEK);
 328                         if (rc) {
 329                                 printk(KERN_ERR "Error attempting to register "
 330                                        "global fnek sig [%s]; rc = [%d]\n",
 331                                        mount_crypt_stat->global_default_fnek_sig,
 332                                        rc);
 333                                 goto out;
 334                         }
 335                         mount_crypt_stat->flags |=
 336                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 337                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 338                         break;
 339                 case ecryptfs_opt_fn_cipher:
 340                         fn_cipher_name_src = args[0].from;
 341                         strscpy(mount_crypt_stat->global_default_fn_cipher_name,
 342                                 fn_cipher_name_src);
 343                         fn_cipher_name_set = 1;
 344                         break;
 345                 case ecryptfs_opt_fn_cipher_key_bytes:
 346                         fn_cipher_key_bytes_src = args[0].from;
 347                         fn_cipher_key_bytes =
 348                                 (int)simple_strtol(fn_cipher_key_bytes_src,
 349                                                    &fn_cipher_key_bytes_src, 0);
 350                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
 351                                 fn_cipher_key_bytes;
 352                         fn_cipher_key_bytes_set = 1;
 353                         break;
 354                 case ecryptfs_opt_unlink_sigs:
 355                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
 356                         break;
 357                 case ecryptfs_opt_mount_auth_tok_only:
 358                         mount_crypt_stat->flags |=
 359                                 ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
 360                         break;
 361                 case ecryptfs_opt_check_dev_ruid:
 362                         *check_ruid = 1;
 363                         break;
 364                 case ecryptfs_opt_err:
 365                 default:
 366                         printk(KERN_WARNING
 367                                "%s: eCryptfs: unrecognized option [%s]\n",
 368                                __func__, p);
 369                 }
 370         }
 371         if (!sig_set) {
 372                 rc = -EINVAL;
 373                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
 374                                 "auth tok signature as a mount "
 375                                 "parameter; see the eCryptfs README\n");
 376                 goto out;
 377         }
 378         if (!cipher_name_set) {
 379                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 380
 381                 BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 382                 strcpy(mount_crypt_stat->global_default_cipher_name,
 383                        ECRYPTFS_DEFAULT_CIPHER);
 384         }
 385         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 386             && !fn_cipher_name_set)
 387                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
 388                        mount_crypt_stat->global_default_cipher_name);
 389         if (!cipher_key_bytes_set)
 390                 mount_crypt_stat->global_default_cipher_key_size = 0;
 391         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 392             && !fn_cipher_key_bytes_set)
 393                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
 394                         mount_crypt_stat->global_default_cipher_key_size;
 395
 396         cipher_code = ecryptfs_code_for_cipher_string(
 397                 mount_crypt_stat->global_default_cipher_name,
 398                 mount_crypt_stat->global_default_cipher_key_size);
 399         if (!cipher_code) {
 400                 ecryptfs_printk(KERN_ERR,
 401                                 "eCryptfs doesn't support cipher: %s\n",
 402                                 mount_crypt_stat->global_default_cipher_name);
 403                 rc = -EINVAL;
 404                 goto out;
 405         }
 406
 407         mutex_lock(&key_tfm_list_mutex);
 408         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
 409                                  NULL)) {
 410                 rc = ecryptfs_add_new_key_tfm(
 411                         NULL, mount_crypt_stat->global_default_cipher_name,
 412                         mount_crypt_stat->global_default_cipher_key_size);
 413                 if (rc) {
 414                         printk(KERN_ERR "Error attempting to initialize "
 415                                "cipher with name = [%s] and key size = [%td]; "
 416                                "rc = [%d]\n",
 417                                mount_crypt_stat->global_default_cipher_name,
 418                                mount_crypt_stat->global_default_cipher_key_size,
 419                                rc);
 420                         rc = -EINVAL;
 421                         mutex_unlock(&key_tfm_list_mutex);
 422                         goto out;
 423                 }
 424         }
 425         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 426             && !ecryptfs_tfm_exists(
 427                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
 428                 rc = ecryptfs_add_new_key_tfm(
 429                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
 430                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
 431                 if (rc) {
 432                         printk(KERN_ERR "Error attempting to initialize "
 433                                "cipher with name = [%s] and key size = [%td]; "
 434                                "rc = [%d]\n",
 435                                mount_crypt_stat->global_default_fn_cipher_name,
 436                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
 437                                rc);
 438                         rc = -EINVAL;
 439                         mutex_unlock(&key_tfm_list_mutex);
 440                         goto out;
 441                 }
 442         }
 443         mutex_unlock(&key_tfm_list_mutex);
 444         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
 445         if (rc)
 446                 printk(KERN_WARNING "One or more global auth toks could not "
 447                        "properly register; rc = [%d]\n", rc);
 448 out:
 449         return rc;
 450 }
 451
 452 struct kmem_cache *ecryptfs_sb_info_cache;
 453 static struct file_system_type ecryptfs_fs_type;
 454
 455 /*
 456  * ecryptfs_mount
 457  * @fs_type: The filesystem type that the superblock should belong to
 458  * @flags: The flags associated with the mount
 459  * @dev_name: The path to mount over
 460  * @raw_data: The options passed into the kernel
 461  */
 462 static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
 463                         const char *dev_name, void *raw_data)
 464 {
 465         struct super_block *s;
 466         struct ecryptfs_sb_info *sbi;
 467         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 468         struct ecryptfs_dentry_info *root_info;
 469         const char *err = "Getting sb failed";
 470         struct inode *inode;
 471         struct path path;
 472         uid_t check_ruid;
 473         int rc;
 474
 475         sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
 476         if (!sbi) {
 477                 rc = -ENOMEM;
 478                 goto out;
 479         }
 480
 481         if (!dev_name) {
 482                 rc = -EINVAL;
 483                 err = "Device name cannot be null";
 484                 goto out;
 485         }
 486
 487         rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
 488         if (rc) {
 489                 err = "Error parsing options";
 490                 goto out;
 491         }
 492         mount_crypt_stat = &sbi->mount_crypt_stat;
 493
 494         s = sget(fs_type, NULL, set_anon_super, flags, NULL);
 495         if (IS_ERR(s)) {
 496                 rc = PTR_ERR(s);
 497                 goto out;
 498         }
 499
 500         rc = super_setup_bdi(s);
 501         if (rc)
 502                 goto out1;
 503
 504         ecryptfs_set_superblock_private(s, sbi);
 505
 506         /* ->kill_sb() will take care of sbi after that point */
 507         sbi = NULL;
 508         s->s_op = &ecryptfs_sops;
 509         s->s_xattr = ecryptfs_xattr_handlers;
 510         s->s_d_op = &ecryptfs_dops;
 511
 512         err = "Reading sb failed";
 513         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 514         if (rc) {
 515                 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
 516                 goto out1;
 517         }
 518         if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
 519                 rc = -EINVAL;
 520                 printk(KERN_ERR "Mount on filesystem of type "
 521                         "eCryptfs explicitly disallowed due to "
 522                         "known incompatibilities\n");
 523                 goto out_free;
 524         }
 525
 526         if (is_idmapped_mnt(path.mnt)) {
 527                 rc = -EINVAL;
 528                 printk(KERN_ERR "Mounting on idmapped mounts currently disallowed\n");
 529                 goto out_free;
 530         }
 531
 532         if (check_ruid && !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) {
 533                 rc = -EPERM;
 534                 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
 535                        "requested user (uid: %d)\n",
 536                         i_uid_read(d_inode(path.dentry)),
 537                         from_kuid(&init_user_ns, current_uid()));
 538                 goto out_free;
 539         }
 540
 541         ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
 542
 543         /**
 544          * Set the POSIX ACL flag based on whether they're enabled in the lower
 545          * mount.
 546          */
 547         s->s_flags = flags & ~SB_POSIXACL;
 548         s->s_flags |= path.dentry->d_sb->s_flags & SB_POSIXACL;
 549
 550         /**
 551          * Force a read-only eCryptfs mount when:
 552          *   1) The lower mount is ro
 553          *   2) The ecryptfs_encrypted_view mount option is specified
 554          */
 555         if (sb_rdonly(path.dentry->d_sb) || mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
 556                 s->s_flags |= SB_RDONLY;
 557
 558         s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 559         s->s_blocksize = path.dentry->d_sb->s_blocksize;
 560         s->s_magic = ECRYPTFS_SUPER_MAGIC;
 561         s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
 562
 563         rc = -EINVAL;
 564         if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
 565                 pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
 566                 goto out_free;
 567         }
 568
 569         inode = ecryptfs_get_inode(d_inode(path.dentry), s);
 570         rc = PTR_ERR(inode);
 571         if (IS_ERR(inode))
 572                 goto out_free;
 573
 574         s->s_root = d_make_root(inode);
 575         if (!s->s_root) {
 576                 rc = -ENOMEM;
 577                 goto out_free;
 578         }
 579
 580         rc = -ENOMEM;
 581         root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 582         if (!root_info)
 583                 goto out_free;
 584
 585         /* ->kill_sb() will take care of root_info */
 586         ecryptfs_set_dentry_private(s->s_root, root_info);
 587         root_info->lower_path = path;
 588
 589         s->s_flags |= SB_ACTIVE;
 590         return dget(s->s_root);
 591
 592 out_free:
 593         path_put(&path);
 594 out1:
 595         deactivate_locked_super(s);
 596 out:
 597         if (sbi) {
 598                 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
 599                 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
 600         }
 601         printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
 602         return ERR_PTR(rc);
 603 }
 604
 605 /**
 606  * ecryptfs_kill_block_super
 607  * @sb: The ecryptfs super block
 608  *
 609  * Used to bring the superblock down and free the private data.
 610  */
 611 static void ecryptfs_kill_block_super(struct super_block *sb)
 612 {
 613         struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
 614         kill_anon_super(sb);
 615         if (!sb_info)
 616                 return;
 617         ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
 618         kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
 619 }
 620
 621 static struct file_system_type ecryptfs_fs_type = {
 622         .owner = THIS_MODULE,
 623         .name = "ecryptfs",
 624         .mount = ecryptfs_mount,
 625         .kill_sb = ecryptfs_kill_block_super,
 626         .fs_flags = 0
 627 };
 628 MODULE_ALIAS_FS("ecryptfs");
 629
 630 /*
 631  * inode_info_init_once
 632  *
 633  * Initializes the ecryptfs_inode_info_cache when it is created
 634  */
 635 static void
 636 inode_info_init_once(void *vptr)
 637 {
 638         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 639
 640         inode_init_once(&ei->vfs_inode);
 641 }
 642
 643 static struct ecryptfs_cache_info {
 644         struct kmem_cache **cache;
 645         const char *name;
 646         size_t size;
 647         slab_flags_t flags;
 648         void (*ctor)(void *obj);
 649 } ecryptfs_cache_infos[] = {
 650         {
 651                 .cache = &ecryptfs_auth_tok_list_item_cache,
 652                 .name = "ecryptfs_auth_tok_list_item",
 653                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 654         },
 655         {
 656                 .cache = &ecryptfs_file_info_cache,
 657                 .name = "ecryptfs_file_cache",
 658                 .size = sizeof(struct ecryptfs_file_info),
 659         },
 660         {
 661                 .cache = &ecryptfs_dentry_info_cache,
 662                 .name = "ecryptfs_dentry_info_cache",
 663                 .size = sizeof(struct ecryptfs_dentry_info),
 664         },
 665         {
 666                 .cache = &ecryptfs_inode_info_cache,
 667                 .name = "ecryptfs_inode_cache",
 668                 .size = sizeof(struct ecryptfs_inode_info),
 669                 .flags = SLAB_ACCOUNT,
 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_SIZE,
 681         },
 682         {
 683                 .cache = &ecryptfs_xattr_cache,
 684                 .name = "ecryptfs_xattr_cache",
 685                 .size = PAGE_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                 kmem_cache_destroy(*(info->cache));
 724         }
 725 }
 726
 727 /**
 728  * ecryptfs_init_kmem_caches
 729  *
 730  * Returns zero on success; non-zero otherwise
 731  */
 732 static int ecryptfs_init_kmem_caches(void)
 733 {
 734         int i;
 735
 736         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 737                 struct ecryptfs_cache_info *info;
 738
 739                 info = &ecryptfs_cache_infos[i];
 740                 *(info->cache) = kmem_cache_create(info->name, info->size, 0,
 741                                 SLAB_HWCACHE_ALIGN | info->flags, info->ctor);
 742                 if (!*(info->cache)) {
 743                         ecryptfs_free_kmem_caches();
 744                         ecryptfs_printk(KERN_WARNING, "%s: "
 745                                         "kmem_cache_create failed\n",
 746                                         info->name);
 747                         return -ENOMEM;
 748                 }
 749         }
 750         return 0;
 751 }
 752
 753 static struct kobject *ecryptfs_kobj;
 754
 755 static ssize_t version_show(struct kobject *kobj,
 756                             struct kobj_attribute *attr, char *buff)
 757 {
 758         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 759 }
 760
 761 static struct kobj_attribute version_attr = __ATTR_RO(version);
 762
 763 static struct attribute *attributes[] = {
 764         &version_attr.attr,
 765         NULL,
 766 };
 767
 768 static const struct attribute_group attr_group = {
 769         .attrs = attributes,
 770 };
 771
 772 static int do_sysfs_registration(void)
 773 {
 774         int rc;
 775
 776         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 777         if (!ecryptfs_kobj) {
 778                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
 779                 rc = -ENOMEM;
 780                 goto out;
 781         }
 782         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 783         if (rc) {
 784                 printk(KERN_ERR
 785                        "Unable to create ecryptfs version attributes\n");
 786                 kobject_put(ecryptfs_kobj);
 787         }
 788 out:
 789         return rc;
 790 }
 791
 792 static void do_sysfs_unregistration(void)
 793 {
 794         sysfs_remove_group(ecryptfs_kobj, &attr_group);
 795         kobject_put(ecryptfs_kobj);
 796 }
 797
 798 static int __init ecryptfs_init(void)
 799 {
 800         int rc;
 801
 802         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_SIZE) {
 803                 rc = -EINVAL;
 804                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 805                                 "larger than the host's page size, and so "
 806                                 "eCryptfs cannot run on this system. The "
 807                                 "default eCryptfs extent size is [%u] bytes; "
 808                                 "the page size is [%lu] bytes.\n",
 809                                 ECRYPTFS_DEFAULT_EXTENT_SIZE,
 810                                 (unsigned long)PAGE_SIZE);
 811                 goto out;
 812         }
 813         rc = ecryptfs_init_kmem_caches();
 814         if (rc) {
 815                 printk(KERN_ERR
 816                        "Failed to allocate one or more kmem_cache objects\n");
 817                 goto out;
 818         }
 819         rc = do_sysfs_registration();
 820         if (rc) {
 821                 printk(KERN_ERR "sysfs registration failed\n");
 822                 goto out_free_kmem_caches;
 823         }
 824         rc = ecryptfs_init_kthread();
 825         if (rc) {
 826                 printk(KERN_ERR "%s: kthread initialization failed; "
 827                        "rc = [%d]\n", __func__, rc);
 828                 goto out_do_sysfs_unregistration;
 829         }
 830         rc = ecryptfs_init_messaging();
 831         if (rc) {
 832                 printk(KERN_ERR "Failure occurred while attempting to "
 833                                 "initialize the communications channel to "
 834                                 "ecryptfsd\n");
 835                 goto out_destroy_kthread;
 836         }
 837         rc = ecryptfs_init_crypto();
 838         if (rc) {
 839                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
 840                        "rc = [%d]\n", rc);
 841                 goto out_release_messaging;
 842         }
 843         rc = register_filesystem(&ecryptfs_fs_type);
 844         if (rc) {
 845                 printk(KERN_ERR "Failed to register filesystem\n");
 846                 goto out_destroy_crypto;
 847         }
 848         if (ecryptfs_verbosity > 0)
 849                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 850                         "will be written to the syslog!\n", ecryptfs_verbosity);
 851
 852         goto out;
 853 out_destroy_crypto:
 854         ecryptfs_destroy_crypto();
 855 out_release_messaging:
 856         ecryptfs_release_messaging();
 857 out_destroy_kthread:
 858         ecryptfs_destroy_kthread();
 859 out_do_sysfs_unregistration:
 860         do_sysfs_unregistration();
 861 out_free_kmem_caches:
 862         ecryptfs_free_kmem_caches();
 863 out:
 864         return rc;
 865 }
 866
 867 static void __exit ecryptfs_exit(void)
 868 {
 869         int rc;
 870
 871         rc = ecryptfs_destroy_crypto();
 872         if (rc)
 873                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 874                        "rc = [%d]\n", rc);
 875         ecryptfs_release_messaging();
 876         ecryptfs_destroy_kthread();
 877         do_sysfs_unregistration();
 878         unregister_filesystem(&ecryptfs_fs_type);
 879         ecryptfs_free_kmem_caches();
 880 }
 881
 882 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 883 MODULE_DESCRIPTION("eCryptfs");
 884
 885 MODULE_LICENSE("GPL");
 886
 887 module_init(ecryptfs_init)
 888 module_exit(ecryptfs_exit)