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 <[email protected]>
   9  *              Michael C. Thompson <[email protected]>
  10  *              Tyler Hicks <[email protected]>
  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/pagemap.h>
  19 #include <linux/key.h>
  20 #include <linux/fs_context.h>
  21 #include <linux/fs_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 {
 157         Opt_sig, Opt_ecryptfs_sig, Opt_cipher, Opt_ecryptfs_cipher,
 158         Opt_ecryptfs_key_bytes, Opt_passthrough, Opt_xattr_metadata,
 159         Opt_encrypted_view, Opt_fnek_sig, Opt_fn_cipher,
 160         Opt_fn_cipher_key_bytes, Opt_unlink_sigs, Opt_mount_auth_tok_only,
 161         Opt_check_dev_ruid
 162 };
 163
 164 static const struct fs_parameter_spec ecryptfs_fs_param_spec[] = {
 165         fsparam_string  ("sig",                     Opt_sig),
 166         fsparam_string  ("ecryptfs_sig",            Opt_ecryptfs_sig),
 167         fsparam_string  ("cipher",                  Opt_cipher),
 168         fsparam_string  ("ecryptfs_cipher",         Opt_ecryptfs_cipher),
 169         fsparam_u32     ("ecryptfs_key_bytes",      Opt_ecryptfs_key_bytes),
 170         fsparam_flag    ("ecryptfs_passthrough",    Opt_passthrough),
 171         fsparam_flag    ("ecryptfs_xattr_metadata", Opt_xattr_metadata),
 172         fsparam_flag    ("ecryptfs_encrypted_view", Opt_encrypted_view),
 173         fsparam_string  ("ecryptfs_fnek_sig",       Opt_fnek_sig),
 174         fsparam_string  ("ecryptfs_fn_cipher",      Opt_fn_cipher),
 175         fsparam_u32     ("ecryptfs_fn_key_bytes",   Opt_fn_cipher_key_bytes),
 176         fsparam_flag    ("ecryptfs_unlink_sigs",    Opt_unlink_sigs),
 177         fsparam_flag    ("ecryptfs_mount_auth_tok_only", Opt_mount_auth_tok_only),
 178         fsparam_flag    ("ecryptfs_check_dev_ruid", Opt_check_dev_ruid),
 179         {}
 180 };
 181
 182 static int ecryptfs_init_global_auth_toks(
 183         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 184 {
 185         struct ecryptfs_global_auth_tok *global_auth_tok;
 186         struct ecryptfs_auth_tok *auth_tok;
 187         int rc = 0;
 188
 189         list_for_each_entry(global_auth_tok,
 190                             &mount_crypt_stat->global_auth_tok_list,
 191                             mount_crypt_stat_list) {
 192                 rc = ecryptfs_keyring_auth_tok_for_sig(
 193                         &global_auth_tok->global_auth_tok_key, &auth_tok,
 194                         global_auth_tok->sig);
 195                 if (rc) {
 196                         printk(KERN_ERR "Could not find valid key in user "
 197                                "session keyring for sig specified in mount "
 198                                "option: [%s]\n", global_auth_tok->sig);
 199                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 200                         goto out;
 201                 } else {
 202                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
 203                         up_write(&(global_auth_tok->global_auth_tok_key)->sem);
 204                 }
 205         }
 206 out:
 207         return rc;
 208 }
 209
 210 static void ecryptfs_init_mount_crypt_stat(
 211         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 212 {
 213         memset((void *)mount_crypt_stat, 0,
 214                sizeof(struct ecryptfs_mount_crypt_stat));
 215         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
 216         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
 217         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
 218 }
 219
 220 struct ecryptfs_fs_context {
 221         /* Mount option status trackers */
 222         bool check_ruid;
 223         bool sig_set;
 224         bool cipher_name_set;
 225         bool cipher_key_bytes_set;
 226         bool fn_cipher_name_set;
 227         bool fn_cipher_key_bytes_set;
 228 };
 229
 230 /**
 231  * ecryptfs_parse_param
 232  * @fc: The ecryptfs filesystem context
 233  * @param: The mount parameter to parse
 234  *
 235  * The signature of the key to use must be the description of a key
 236  * already in the keyring. Mounting will fail if the key can not be
 237  * found.
 238  *
 239  * Returns zero on success; non-zero on error
 240  */
 241 static int ecryptfs_parse_param(
 242         struct fs_context *fc,
 243         struct fs_parameter *param)
 244 {
 245         int rc;
 246         int opt;
 247         struct fs_parse_result result;
 248         struct ecryptfs_fs_context *ctx = fc->fs_private;
 249         struct ecryptfs_sb_info *sbi = fc->s_fs_info;
 250         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 251                 &sbi->mount_crypt_stat;
 252
 253         opt = fs_parse(fc, ecryptfs_fs_param_spec, param, &result);
 254         if (opt < 0)
 255                 return opt;
 256
 257         switch (opt) {
 258         case Opt_sig:
 259         case Opt_ecryptfs_sig:
 260                 rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
 261                                                   param->string, 0);
 262                 if (rc) {
 263                         printk(KERN_ERR "Error attempting to register "
 264                                "global sig; rc = [%d]\n", rc);
 265                         return rc;
 266                 }
 267                 ctx->sig_set = 1;
 268                 break;
 269         case Opt_cipher:
 270         case Opt_ecryptfs_cipher:
 271                 strscpy(mount_crypt_stat->global_default_cipher_name,
 272                         param->string);
 273                 ctx->cipher_name_set = 1;
 274                 break;
 275         case Opt_ecryptfs_key_bytes:
 276                 mount_crypt_stat->global_default_cipher_key_size =
 277                         result.uint_32;
 278                 ctx->cipher_key_bytes_set = 1;
 279                 break;
 280         case Opt_passthrough:
 281                 mount_crypt_stat->flags |=
 282                         ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 283                 break;
 284         case Opt_xattr_metadata:
 285                 mount_crypt_stat->flags |= ECRYPTFS_XATTR_METADATA_ENABLED;
 286                 break;
 287         case Opt_encrypted_view:
 288                 mount_crypt_stat->flags |= ECRYPTFS_XATTR_METADATA_ENABLED;
 289                 mount_crypt_stat->flags |= ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 290                 break;
 291         case Opt_fnek_sig:
 292                 strscpy(mount_crypt_stat->global_default_fnek_sig,
 293                         param->string);
 294                 rc = ecryptfs_add_global_auth_tok(
 295                         mount_crypt_stat,
 296                         mount_crypt_stat->global_default_fnek_sig,
 297                         ECRYPTFS_AUTH_TOK_FNEK);
 298                 if (rc) {
 299                         printk(KERN_ERR "Error attempting to register "
 300                                "global fnek sig [%s]; rc = [%d]\n",
 301                                mount_crypt_stat->global_default_fnek_sig, rc);
 302                         return rc;
 303                 }
 304                 mount_crypt_stat->flags |=
 305                         (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 306                          | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 307                 break;
 308         case Opt_fn_cipher:
 309                 strscpy(mount_crypt_stat->global_default_fn_cipher_name,
 310                         param->string);
 311                 ctx->fn_cipher_name_set = 1;
 312                 break;
 313         case Opt_fn_cipher_key_bytes:
 314                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
 315                         result.uint_32;
 316                 ctx->fn_cipher_key_bytes_set = 1;
 317                 break;
 318         case Opt_unlink_sigs:
 319                 mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
 320                 break;
 321         case Opt_mount_auth_tok_only:
 322                 mount_crypt_stat->flags |= ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
 323                 break;
 324         case Opt_check_dev_ruid:
 325                 ctx->check_ruid = 1;
 326                 break;
 327         default:
 328                 return -EINVAL;
 329         }
 330
 331         return 0;
 332 }
 333
 334 static int ecryptfs_validate_options(struct fs_context *fc)
 335 {
 336         int rc = 0;
 337         u8 cipher_code;
 338         struct ecryptfs_fs_context *ctx = fc->fs_private;
 339         struct ecryptfs_sb_info *sbi = fc->s_fs_info;
 340         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 341
 342
 343         mount_crypt_stat = &sbi->mount_crypt_stat;
 344
 345         if (!ctx->sig_set) {
 346                 rc = -EINVAL;
 347                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
 348                                 "auth tok signature as a mount "
 349                                 "parameter; see the eCryptfs README\n");
 350                 goto out;
 351         }
 352         if (!ctx->cipher_name_set) {
 353                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 354
 355                 BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 356                 strcpy(mount_crypt_stat->global_default_cipher_name,
 357                        ECRYPTFS_DEFAULT_CIPHER);
 358         }
 359         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 360             && !ctx->fn_cipher_name_set)
 361                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
 362                        mount_crypt_stat->global_default_cipher_name);
 363         if (!ctx->cipher_key_bytes_set)
 364                 mount_crypt_stat->global_default_cipher_key_size = 0;
 365         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 366             && !ctx->fn_cipher_key_bytes_set)
 367                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
 368                         mount_crypt_stat->global_default_cipher_key_size;
 369
 370         cipher_code = ecryptfs_code_for_cipher_string(
 371                 mount_crypt_stat->global_default_cipher_name,
 372                 mount_crypt_stat->global_default_cipher_key_size);
 373         if (!cipher_code) {
 374                 ecryptfs_printk(KERN_ERR,
 375                                 "eCryptfs doesn't support cipher: %s\n",
 376                                 mount_crypt_stat->global_default_cipher_name);
 377                 rc = -EINVAL;
 378                 goto out;
 379         }
 380
 381         mutex_lock(&key_tfm_list_mutex);
 382         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
 383                                  NULL)) {
 384                 rc = ecryptfs_add_new_key_tfm(
 385                         NULL, mount_crypt_stat->global_default_cipher_name,
 386                         mount_crypt_stat->global_default_cipher_key_size);
 387                 if (rc) {
 388                         printk(KERN_ERR "Error attempting to initialize "
 389                                "cipher with name = [%s] and key size = [%td]; "
 390                                "rc = [%d]\n",
 391                                mount_crypt_stat->global_default_cipher_name,
 392                                mount_crypt_stat->global_default_cipher_key_size,
 393                                rc);
 394                         rc = -EINVAL;
 395                         mutex_unlock(&key_tfm_list_mutex);
 396                         goto out;
 397                 }
 398         }
 399         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 400             && !ecryptfs_tfm_exists(
 401                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
 402                 rc = ecryptfs_add_new_key_tfm(
 403                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
 404                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
 405                 if (rc) {
 406                         printk(KERN_ERR "Error attempting to initialize "
 407                                "cipher with name = [%s] and key size = [%td]; "
 408                                "rc = [%d]\n",
 409                                mount_crypt_stat->global_default_fn_cipher_name,
 410                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
 411                                rc);
 412                         rc = -EINVAL;
 413                         mutex_unlock(&key_tfm_list_mutex);
 414                         goto out;
 415                 }
 416         }
 417         mutex_unlock(&key_tfm_list_mutex);
 418         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
 419         if (rc)
 420                 printk(KERN_WARNING "One or more global auth toks could not "
 421                        "properly register; rc = [%d]\n", rc);
 422 out:
 423         return rc;
 424 }
 425
 426 struct kmem_cache *ecryptfs_sb_info_cache;
 427 static struct file_system_type ecryptfs_fs_type;
 428
 429 /*
 430  * ecryptfs_get_tree
 431  * @fc: The filesystem context
 432  */
 433 static int ecryptfs_get_tree(struct fs_context *fc)
 434 {
 435         struct super_block *s;
 436         struct ecryptfs_fs_context *ctx = fc->fs_private;
 437         struct ecryptfs_sb_info *sbi = fc->s_fs_info;
 438         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 439         struct ecryptfs_dentry_info *root_info;
 440         const char *err = "Getting sb failed";
 441         struct inode *inode;
 442         struct path path;
 443         int rc;
 444
 445         if (!fc->source) {
 446                 rc = -EINVAL;
 447                 err = "Device name cannot be null";
 448                 goto out;
 449         }
 450
 451         mount_crypt_stat = &sbi->mount_crypt_stat;
 452         rc = ecryptfs_validate_options(fc);
 453         if (rc) {
 454                 err = "Error validating options";
 455                 goto out;
 456         }
 457
 458         s = sget_fc(fc, NULL, set_anon_super_fc);
 459         if (IS_ERR(s)) {
 460                 rc = PTR_ERR(s);
 461                 goto out;
 462         }
 463
 464         rc = super_setup_bdi(s);
 465         if (rc)
 466                 goto out1;
 467
 468         ecryptfs_set_superblock_private(s, sbi);
 469
 470         /* ->kill_sb() will take care of sbi after that point */
 471         sbi = NULL;
 472         s->s_op = &ecryptfs_sops;
 473         s->s_xattr = ecryptfs_xattr_handlers;
 474         s->s_d_op = &ecryptfs_dops;
 475
 476         err = "Reading sb failed";
 477         rc = kern_path(fc->source, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 478         if (rc) {
 479                 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
 480                 goto out1;
 481         }
 482         if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
 483                 rc = -EINVAL;
 484                 printk(KERN_ERR "Mount on filesystem of type "
 485                         "eCryptfs explicitly disallowed due to "
 486                         "known incompatibilities\n");
 487                 goto out_free;
 488         }
 489
 490         if (is_idmapped_mnt(path.mnt)) {
 491                 rc = -EINVAL;
 492                 printk(KERN_ERR "Mounting on idmapped mounts currently disallowed\n");
 493                 goto out_free;
 494         }
 495
 496         if (ctx->check_ruid &&
 497             !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) {
 498                 rc = -EPERM;
 499                 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
 500                        "requested user (uid: %d)\n",
 501                         i_uid_read(d_inode(path.dentry)),
 502                         from_kuid(&init_user_ns, current_uid()));
 503                 goto out_free;
 504         }
 505
 506         ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
 507
 508         /**
 509          * Set the POSIX ACL flag based on whether they're enabled in the lower
 510          * mount.
 511          */
 512         s->s_flags = fc->sb_flags & ~SB_POSIXACL;
 513         s->s_flags |= path.dentry->d_sb->s_flags & SB_POSIXACL;
 514
 515         /**
 516          * Force a read-only eCryptfs mount when:
 517          *   1) The lower mount is ro
 518          *   2) The ecryptfs_encrypted_view mount option is specified
 519          */
 520         if (sb_rdonly(path.dentry->d_sb) || mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
 521                 s->s_flags |= SB_RDONLY;
 522
 523         s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 524         s->s_blocksize = path.dentry->d_sb->s_blocksize;
 525         s->s_magic = ECRYPTFS_SUPER_MAGIC;
 526         s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
 527
 528         rc = -EINVAL;
 529         if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
 530                 pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
 531                 goto out_free;
 532         }
 533
 534         inode = ecryptfs_get_inode(d_inode(path.dentry), s);
 535         rc = PTR_ERR(inode);
 536         if (IS_ERR(inode))
 537                 goto out_free;
 538
 539         s->s_root = d_make_root(inode);
 540         if (!s->s_root) {
 541                 rc = -ENOMEM;
 542                 goto out_free;
 543         }
 544
 545         rc = -ENOMEM;
 546         root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 547         if (!root_info)
 548                 goto out_free;
 549
 550         /* ->kill_sb() will take care of root_info */
 551         ecryptfs_set_dentry_private(s->s_root, root_info);
 552         root_info->lower_path = path;
 553
 554         s->s_flags |= SB_ACTIVE;
 555         fc->root = dget(s->s_root);
 556         return 0;
 557
 558 out_free:
 559         path_put(&path);
 560 out1:
 561         deactivate_locked_super(s);
 562 out:
 563         if (sbi)
 564                 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
 565
 566         printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
 567         return rc;
 568 }
 569
 570 /**
 571  * ecryptfs_kill_block_super
 572  * @sb: The ecryptfs super block
 573  *
 574  * Used to bring the superblock down and free the private data.
 575  */
 576 static void ecryptfs_kill_block_super(struct super_block *sb)
 577 {
 578         struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
 579         kill_anon_super(sb);
 580         if (!sb_info)
 581                 return;
 582         ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
 583         kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
 584 }
 585
 586 static void ecryptfs_free_fc(struct fs_context *fc)
 587 {
 588         struct ecryptfs_fs_context *ctx = fc->fs_private;
 589         struct ecryptfs_sb_info *sbi = fc->s_fs_info;
 590
 591         kfree(ctx);
 592
 593         if (sbi) {
 594                 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
 595                 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
 596         }
 597 }
 598
 599 static const struct fs_context_operations ecryptfs_context_ops = {
 600         .free           = ecryptfs_free_fc,
 601         .parse_param    = ecryptfs_parse_param,
 602         .get_tree       = ecryptfs_get_tree,
 603         .reconfigure    = NULL,
 604 };
 605
 606 static int ecryptfs_init_fs_context(struct fs_context *fc)
 607 {
 608         struct ecryptfs_fs_context *ctx;
 609         struct ecryptfs_sb_info *sbi = NULL;
 610
 611         ctx = kzalloc(sizeof(struct ecryptfs_fs_context), GFP_KERNEL);
 612         if (!ctx)
 613                 return -ENOMEM;
 614         sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
 615         if (!sbi) {
 616                 kfree(ctx);
 617                 ctx = NULL;
 618                 return -ENOMEM;
 619         }
 620
 621         ecryptfs_init_mount_crypt_stat(&sbi->mount_crypt_stat);
 622
 623         fc->fs_private = ctx;
 624         fc->s_fs_info = sbi;
 625         fc->ops = &ecryptfs_context_ops;
 626         return 0;
 627 }
 628
 629 static struct file_system_type ecryptfs_fs_type = {
 630         .owner = THIS_MODULE,
 631         .name = "ecryptfs",
 632         .init_fs_context = ecryptfs_init_fs_context,
 633         .parameters = ecryptfs_fs_param_spec,
 634         .kill_sb = ecryptfs_kill_block_super,
 635         .fs_flags = 0
 636 };
 637 MODULE_ALIAS_FS("ecryptfs");
 638
 639 /*
 640  * inode_info_init_once
 641  *
 642  * Initializes the ecryptfs_inode_info_cache when it is created
 643  */
 644 static void
 645 inode_info_init_once(void *vptr)
 646 {
 647         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 648
 649         inode_init_once(&ei->vfs_inode);
 650 }
 651
 652 static struct ecryptfs_cache_info {
 653         struct kmem_cache **cache;
 654         const char *name;
 655         size_t size;
 656         slab_flags_t flags;
 657         void (*ctor)(void *obj);
 658 } ecryptfs_cache_infos[] = {
 659         {
 660                 .cache = &ecryptfs_auth_tok_list_item_cache,
 661                 .name = "ecryptfs_auth_tok_list_item",
 662                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
 663         },
 664         {
 665                 .cache = &ecryptfs_file_info_cache,
 666                 .name = "ecryptfs_file_cache",
 667                 .size = sizeof(struct ecryptfs_file_info),
 668         },
 669         {
 670                 .cache = &ecryptfs_dentry_info_cache,
 671                 .name = "ecryptfs_dentry_info_cache",
 672                 .size = sizeof(struct ecryptfs_dentry_info),
 673         },
 674         {
 675                 .cache = &ecryptfs_inode_info_cache,
 676                 .name = "ecryptfs_inode_cache",
 677                 .size = sizeof(struct ecryptfs_inode_info),
 678                 .flags = SLAB_ACCOUNT,
 679                 .ctor = inode_info_init_once,
 680         },
 681         {
 682                 .cache = &ecryptfs_sb_info_cache,
 683                 .name = "ecryptfs_sb_cache",
 684                 .size = sizeof(struct ecryptfs_sb_info),
 685         },
 686         {
 687                 .cache = &ecryptfs_header_cache,
 688                 .name = "ecryptfs_headers",
 689                 .size = PAGE_SIZE,
 690         },
 691         {
 692                 .cache = &ecryptfs_xattr_cache,
 693                 .name = "ecryptfs_xattr_cache",
 694                 .size = PAGE_SIZE,
 695         },
 696         {
 697                 .cache = &ecryptfs_key_record_cache,
 698                 .name = "ecryptfs_key_record_cache",
 699                 .size = sizeof(struct ecryptfs_key_record),
 700         },
 701         {
 702                 .cache = &ecryptfs_key_sig_cache,
 703                 .name = "ecryptfs_key_sig_cache",
 704                 .size = sizeof(struct ecryptfs_key_sig),
 705         },
 706         {
 707                 .cache = &ecryptfs_global_auth_tok_cache,
 708                 .name = "ecryptfs_global_auth_tok_cache",
 709                 .size = sizeof(struct ecryptfs_global_auth_tok),
 710         },
 711         {
 712                 .cache = &ecryptfs_key_tfm_cache,
 713                 .name = "ecryptfs_key_tfm_cache",
 714                 .size = sizeof(struct ecryptfs_key_tfm),
 715         },
 716 };
 717
 718 static void ecryptfs_free_kmem_caches(void)
 719 {
 720         int i;
 721
 722         /*
 723          * Make sure all delayed rcu free inodes are flushed before we
 724          * destroy cache.
 725          */
 726         rcu_barrier();
 727
 728         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 729                 struct ecryptfs_cache_info *info;
 730
 731                 info = &ecryptfs_cache_infos[i];
 732                 kmem_cache_destroy(*(info->cache));
 733         }
 734 }
 735
 736 /**
 737  * ecryptfs_init_kmem_caches
 738  *
 739  * Returns zero on success; non-zero otherwise
 740  */
 741 static int ecryptfs_init_kmem_caches(void)
 742 {
 743         int i;
 744
 745         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 746                 struct ecryptfs_cache_info *info;
 747
 748                 info = &ecryptfs_cache_infos[i];
 749                 *(info->cache) = kmem_cache_create(info->name, info->size, 0,
 750                                 SLAB_HWCACHE_ALIGN | info->flags, info->ctor);
 751                 if (!*(info->cache)) {
 752                         ecryptfs_free_kmem_caches();
 753                         ecryptfs_printk(KERN_WARNING, "%s: "
 754                                         "kmem_cache_create failed\n",
 755                                         info->name);
 756                         return -ENOMEM;
 757                 }
 758         }
 759         return 0;
 760 }
 761
 762 static struct kobject *ecryptfs_kobj;
 763
 764 static ssize_t version_show(struct kobject *kobj,
 765                             struct kobj_attribute *attr, char *buff)
 766 {
 767         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 768 }
 769
 770 static struct kobj_attribute version_attr = __ATTR_RO(version);
 771
 772 static struct attribute *attributes[] = {
 773         &version_attr.attr,
 774         NULL,
 775 };
 776
 777 static const struct attribute_group attr_group = {
 778         .attrs = attributes,
 779 };
 780
 781 static int do_sysfs_registration(void)
 782 {
 783         int rc;
 784
 785         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 786         if (!ecryptfs_kobj) {
 787                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
 788                 rc = -ENOMEM;
 789                 goto out;
 790         }
 791         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 792         if (rc) {
 793                 printk(KERN_ERR
 794                        "Unable to create ecryptfs version attributes\n");
 795                 kobject_put(ecryptfs_kobj);
 796         }
 797 out:
 798         return rc;
 799 }
 800
 801 static void do_sysfs_unregistration(void)
 802 {
 803         sysfs_remove_group(ecryptfs_kobj, &attr_group);
 804         kobject_put(ecryptfs_kobj);
 805 }
 806
 807 static int __init ecryptfs_init(void)
 808 {
 809         int rc;
 810
 811         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_SIZE) {
 812                 rc = -EINVAL;
 813                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 814                                 "larger than the host's page size, and so "
 815                                 "eCryptfs cannot run on this system. The "
 816                                 "default eCryptfs extent size is [%u] bytes; "
 817                                 "the page size is [%lu] bytes.\n",
 818                                 ECRYPTFS_DEFAULT_EXTENT_SIZE,
 819                                 (unsigned long)PAGE_SIZE);
 820                 goto out;
 821         }
 822         rc = ecryptfs_init_kmem_caches();
 823         if (rc) {
 824                 printk(KERN_ERR
 825                        "Failed to allocate one or more kmem_cache objects\n");
 826                 goto out;
 827         }
 828         rc = do_sysfs_registration();
 829         if (rc) {
 830                 printk(KERN_ERR "sysfs registration failed\n");
 831                 goto out_free_kmem_caches;
 832         }
 833         rc = ecryptfs_init_kthread();
 834         if (rc) {
 835                 printk(KERN_ERR "%s: kthread initialization failed; "
 836                        "rc = [%d]\n", __func__, rc);
 837                 goto out_do_sysfs_unregistration;
 838         }
 839         rc = ecryptfs_init_messaging();
 840         if (rc) {
 841                 printk(KERN_ERR "Failure occurred while attempting to "
 842                                 "initialize the communications channel to "
 843                                 "ecryptfsd\n");
 844                 goto out_destroy_kthread;
 845         }
 846         rc = ecryptfs_init_crypto();
 847         if (rc) {
 848                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
 849                        "rc = [%d]\n", rc);
 850                 goto out_release_messaging;
 851         }
 852         rc = register_filesystem(&ecryptfs_fs_type);
 853         if (rc) {
 854                 printk(KERN_ERR "Failed to register filesystem\n");
 855                 goto out_destroy_crypto;
 856         }
 857         if (ecryptfs_verbosity > 0)
 858                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 859                         "will be written to the syslog!\n", ecryptfs_verbosity);
 860
 861         goto out;
 862 out_destroy_crypto:
 863         ecryptfs_destroy_crypto();
 864 out_release_messaging:
 865         ecryptfs_release_messaging();
 866 out_destroy_kthread:
 867         ecryptfs_destroy_kthread();
 868 out_do_sysfs_unregistration:
 869         do_sysfs_unregistration();
 870 out_free_kmem_caches:
 871         ecryptfs_free_kmem_caches();
 872 out:
 873         return rc;
 874 }
 875
 876 static void __exit ecryptfs_exit(void)
 877 {
 878         int rc;
 879
 880         rc = ecryptfs_destroy_crypto();
 881         if (rc)
 882                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 883                        "rc = [%d]\n", rc);
 884         ecryptfs_release_messaging();
 885         ecryptfs_destroy_kthread();
 886         do_sysfs_unregistration();
 887         unregister_filesystem(&ecryptfs_fs_type);
 888         ecryptfs_free_kmem_caches();
 889 }
 890
 891 MODULE_AUTHOR("Michael A. Halcrow <[email protected]>");
 892 MODULE_DESCRIPTION("eCryptfs");
 893
 894 MODULE_LICENSE("GPL");
 895
 896 module_init(ecryptfs_init)
 897 module_exit(ecryptfs_exit)