Quelle  main.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * eCryptfs: Linux filesystem encryption layer
 *
 * Copyright (C) 1997-2003 Erez Zadok
 * Copyright (C) 2001-2003 Stony Brook University
 * Copyright (C) 2004-2007 International Business Machines Corp.
 *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
 *              Michael C. Thompson <mcthomps@us.ibm.com>
 *              Tyler Hicks <code@tyhicks.com>
 */

#include <linux/dcache.h>
#include <linux/file.h>
#include <linux/module.h>
#include <linux/namei.h>
#include <linux/skbuff.h>
#include <linux/pagemap.h>
#include <linux/key.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/fs_stack.h>
#include <linux/sysfs.h>
#include <linux/slab.h>
#include <linux/magic.h>
#include "ecryptfs_kernel.h"

/*
 * Module parameter that defines the ecryptfs_verbosity level.
 */
int ecryptfs_verbosity = 0;

module_param(ecryptfs_verbosity, int, 0);
MODULE_PARM_DESC(ecryptfs_verbosity,
   "Initial verbosity level (0 or 1; defaults to "
   "0, which is Quiet)");

/*
 * Module parameter that defines the number of message buffer elements
 */
unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;

module_param(ecryptfs_message_buf_len, uint, 0);
MODULE_PARM_DESC(ecryptfs_message_buf_len,
   "Number of message buffer elements");

/*
 * Module parameter that defines the maximum guaranteed amount of time to wait
 * for a response from ecryptfsd.  The actual sleep time will be, more than
 * likely, a small amount greater than this specified value, but only less if
 * the message successfully arrives.
 */
signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;

module_param(ecryptfs_message_wait_timeout, long, 0);
MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
   "Maximum number of seconds that an operation will "
   "sleep while waiting for a message response from "
   "userspace");

/*
 * Module parameter that is an estimate of the maximum number of users
 * that will be concurrently using eCryptfs. Set this to the right
 * value to balance performance and memory use.
 */
unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;

module_param(ecryptfs_number_of_users, uint, 0);
MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
   "concurrent users of eCryptfs");

void __ecryptfs_printk(const char *fmt, ...)
{
 va_list args;
 va_start(args, fmt);
 if (fmt[1] == '7') { /* KERN_DEBUG */
  if (ecryptfs_verbosity >= 1)
   vprintk(fmt, args);
 } else
  vprintk(fmt, args);
 va_end(args);
}

/*
 * ecryptfs_init_lower_file
 * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
 *                   the lower dentry and the lower mount set
 *
 * eCryptfs only ever keeps a single open file for every lower
 * inode. All I/O operations to the lower inode occur through that
 * file. When the first eCryptfs dentry that interposes with the first
 * lower dentry for that inode is created, this function creates the
 * lower file struct and associates it with the eCryptfs
 * inode. When all eCryptfs files associated with the inode are released, the
 * file is closed.
 *
 * The lower file will be opened with read/write permissions, if
 * possible. Otherwise, it is opened read-only.
 *
 * This function does nothing if a lower file is already
 * associated with the eCryptfs inode.
 *
 * Returns zero on success; non-zero otherwise
 */
static int ecryptfs_init_lower_file(struct dentry *dentry,
        struct file **lower_file)
{
 const struct cred *cred = current_cred();
 const struct path *path = ecryptfs_dentry_to_lower_path(dentry);
 int rc;

 rc = ecryptfs_privileged_open(lower_file, path->dentry, path->mnt,
          cred);
 if (rc) {
  printk(KERN_ERR "Error opening lower file "
         "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
         "rc = [%d]\n", path->dentry, path->mnt, rc);
  (*lower_file) = NULL;
 }
 return rc;
}

int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
{
 struct ecryptfs_inode_info *inode_info;
 int count, rc = 0;

 inode_info = ecryptfs_inode_to_private(inode);
 mutex_lock(&inode_info->lower_file_mutex);
 count = atomic_inc_return(&inode_info->lower_file_count);
 if (WARN_ON_ONCE(count < 1))
  rc = -EINVAL;
 else if (count == 1) {
  rc = ecryptfs_init_lower_file(dentry,
           &inode_info->lower_file);
  if (rc)
   atomic_set(&inode_info->lower_file_count, 0);
 }
 mutex_unlock(&inode_info->lower_file_mutex);
 return rc;
}

void ecryptfs_put_lower_file(struct inode *inode)
{
 struct ecryptfs_inode_info *inode_info;

 inode_info = ecryptfs_inode_to_private(inode);
 if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
          &inode_info->lower_file_mutex)) {
  filemap_write_and_wait(inode->i_mapping);
  fput(inode_info->lower_file);
  inode_info->lower_file = NULL;
  mutex_unlock(&inode_info->lower_file_mutex);
 }
}

enum {
 Opt_sig, Opt_ecryptfs_sig, Opt_cipher, Opt_ecryptfs_cipher,
 Opt_ecryptfs_key_bytes, Opt_passthrough, Opt_xattr_metadata,
 Opt_encrypted_view, Opt_fnek_sig, Opt_fn_cipher,
 Opt_fn_cipher_key_bytes, Opt_unlink_sigs, Opt_mount_auth_tok_only,
 Opt_check_dev_ruid
};

static const struct fs_parameter_spec ecryptfs_fs_param_spec[] = {
 fsparam_string ("sig",       Opt_sig),
 fsparam_string ("ecryptfs_sig",     Opt_ecryptfs_sig),
 fsparam_string ("cipher",      Opt_cipher),
 fsparam_string ("ecryptfs_cipher",     Opt_ecryptfs_cipher),
 fsparam_u32 ("ecryptfs_key_bytes",     Opt_ecryptfs_key_bytes),
 fsparam_flag ("ecryptfs_passthrough",    Opt_passthrough),
 fsparam_flag ("ecryptfs_xattr_metadata", Opt_xattr_metadata),
 fsparam_flag ("ecryptfs_encrypted_view", Opt_encrypted_view),
 fsparam_string ("ecryptfs_fnek_sig",     Opt_fnek_sig),
 fsparam_string ("ecryptfs_fn_cipher",     Opt_fn_cipher),
 fsparam_u32 ("ecryptfs_fn_key_bytes",   Opt_fn_cipher_key_bytes),
 fsparam_flag ("ecryptfs_unlink_sigs",    Opt_unlink_sigs),
 fsparam_flag ("ecryptfs_mount_auth_tok_only", Opt_mount_auth_tok_only),
 fsparam_flag ("ecryptfs_check_dev_ruid", Opt_check_dev_ruid),
 {}
};

static int ecryptfs_init_global_auth_toks(
 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
{
 struct ecryptfs_global_auth_tok *global_auth_tok;
 struct ecryptfs_auth_tok *auth_tok;
 int rc = 0;

 list_for_each_entry(global_auth_tok,
       &mount_crypt_stat->global_auth_tok_list,
       mount_crypt_stat_list) {
  rc = ecryptfs_keyring_auth_tok_for_sig(
   &global_auth_tok->global_auth_tok_key, &auth_tok,
   global_auth_tok->sig);
  if (rc) {
   printk(KERN_ERR "Could not find valid key in user "
          "session keyring for sig specified in mount "
          "option: [%s]\n", global_auth_tok->sig);
   global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
   goto out;
  } else {
   global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
   up_write(&(global_auth_tok->global_auth_tok_key)->sem);
  }
 }
out:
 return rc;
}

static void ecryptfs_init_mount_crypt_stat(
 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
{
 memset((void *)mount_crypt_stat, 0,
        sizeof(struct ecryptfs_mount_crypt_stat));
 INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
 mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
 mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
}

struct ecryptfs_fs_context {
 /* Mount option status trackers */
 bool check_ruid;
 bool sig_set;
 bool cipher_name_set;
 bool cipher_key_bytes_set;
 bool fn_cipher_name_set;
 bool fn_cipher_key_bytes_set;
};

/**
 * ecryptfs_parse_param
 * @fc: The ecryptfs filesystem context
 * @param: The mount parameter to parse
 *
 * The signature of the key to use must be the description of a key
 * already in the keyring. Mounting will fail if the key can not be
 * found.
 *
 * Returns zero on success; non-zero on error
 */
static int ecryptfs_parse_param(
 struct fs_context *fc,
 struct fs_parameter *param)
{
 int rc;
 int opt;
 struct fs_parse_result result;
 struct ecryptfs_fs_context *ctx = fc->fs_private;
 struct ecryptfs_sb_info *sbi = fc->s_fs_info;
 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
  &sbi->mount_crypt_stat;

 opt = fs_parse(fc, ecryptfs_fs_param_spec, param, &result);
 if (opt < 0)
  return opt;

 switch (opt) {
 case Opt_sig:
 case Opt_ecryptfs_sig:
  rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
        param->string, 0);
  if (rc) {
   printk(KERN_ERR "Error attempting to register "
          "global sig; rc = [%d]\n", rc);
   return rc;
  }
  ctx->sig_set = 1;
  break;
 case Opt_cipher:
 case Opt_ecryptfs_cipher:
  strscpy(mount_crypt_stat->global_default_cipher_name,
   param->string);
  ctx->cipher_name_set = 1;
  break;
 case Opt_ecryptfs_key_bytes:
  mount_crypt_stat->global_default_cipher_key_size =
   result.uint_32;
  ctx->cipher_key_bytes_set = 1;
  break;
 case Opt_passthrough:
  mount_crypt_stat->flags |=
   ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
  break;
 case Opt_xattr_metadata:
  mount_crypt_stat->flags |= ECRYPTFS_XATTR_METADATA_ENABLED;
  break;
 case Opt_encrypted_view:
  mount_crypt_stat->flags |= ECRYPTFS_XATTR_METADATA_ENABLED;
  mount_crypt_stat->flags |= ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
  break;
 case Opt_fnek_sig:
  strscpy(mount_crypt_stat->global_default_fnek_sig,
   param->string);
  rc = ecryptfs_add_global_auth_tok(
   mount_crypt_stat,
   mount_crypt_stat->global_default_fnek_sig,
   ECRYPTFS_AUTH_TOK_FNEK);
  if (rc) {
   printk(KERN_ERR "Error attempting to register "
          "global fnek sig [%s]; rc = [%d]\n",
          mount_crypt_stat->global_default_fnek_sig, rc);
   return rc;
  }
  mount_crypt_stat->flags |=
   (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
    | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
  break;
 case Opt_fn_cipher:
  strscpy(mount_crypt_stat->global_default_fn_cipher_name,
   param->string);
  ctx->fn_cipher_name_set = 1;
  break;
 case Opt_fn_cipher_key_bytes:
  mount_crypt_stat->global_default_fn_cipher_key_bytes =
   result.uint_32;
  ctx->fn_cipher_key_bytes_set = 1;
  break;
 case Opt_unlink_sigs:
  mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
  break;
 case Opt_mount_auth_tok_only:
  mount_crypt_stat->flags |= ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
  break;
 case Opt_check_dev_ruid:
  ctx->check_ruid = 1;
  break;
 default:
  return -EINVAL;
 }

 return 0;
}

static int ecryptfs_validate_options(struct fs_context *fc)
{
 int rc = 0;
 u8 cipher_code;
 struct ecryptfs_fs_context *ctx = fc->fs_private;
 struct ecryptfs_sb_info *sbi = fc->s_fs_info;
 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;


 mount_crypt_stat = &sbi->mount_crypt_stat;

 if (!ctx->sig_set) {
  rc = -EINVAL;
  ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
    "auth tok signature as a mount "
    "parameter; see the eCryptfs README\n");
  goto out;
 }
 if (!ctx->cipher_name_set) {
  int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);

  BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
  strcpy(mount_crypt_stat->global_default_cipher_name,
         ECRYPTFS_DEFAULT_CIPHER);
 }
 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
     && !ctx->fn_cipher_name_set)
  strcpy(mount_crypt_stat->global_default_fn_cipher_name,
         mount_crypt_stat->global_default_cipher_name);
 if (!ctx->cipher_key_bytes_set)
  mount_crypt_stat->global_default_cipher_key_size = 0;
 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
     && !ctx->fn_cipher_key_bytes_set)
  mount_crypt_stat->global_default_fn_cipher_key_bytes =
   mount_crypt_stat->global_default_cipher_key_size;

 cipher_code = ecryptfs_code_for_cipher_string(
  mount_crypt_stat->global_default_cipher_name,
  mount_crypt_stat->global_default_cipher_key_size);
 if (!cipher_code) {
  ecryptfs_printk(KERN_ERR,
    "eCryptfs doesn't support cipher: %s\n",
    mount_crypt_stat->global_default_cipher_name);
  rc = -EINVAL;
  goto out;
 }

 mutex_lock(&key_tfm_list_mutex);
 if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
     NULL)) {
  rc = ecryptfs_add_new_key_tfm(
   NULL, mount_crypt_stat->global_default_cipher_name,
   mount_crypt_stat->global_default_cipher_key_size);
  if (rc) {
   printk(KERN_ERR "Error attempting to initialize "
          "cipher with name = [%s] and key size = [%td]; "
          "rc = [%d]\n",
          mount_crypt_stat->global_default_cipher_name,
          mount_crypt_stat->global_default_cipher_key_size,
          rc);
   rc = -EINVAL;
   mutex_unlock(&key_tfm_list_mutex);
   goto out;
  }
 }
 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
     && !ecryptfs_tfm_exists(
      mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
  rc = ecryptfs_add_new_key_tfm(
   NULL, mount_crypt_stat->global_default_fn_cipher_name,
   mount_crypt_stat->global_default_fn_cipher_key_bytes);
  if (rc) {
   printk(KERN_ERR "Error attempting to initialize "
          "cipher with name = [%s] and key size = [%td]; "
          "rc = [%d]\n",
          mount_crypt_stat->global_default_fn_cipher_name,
          mount_crypt_stat->global_default_fn_cipher_key_bytes,
          rc);
   rc = -EINVAL;
   mutex_unlock(&key_tfm_list_mutex);
   goto out;
  }
 }
 mutex_unlock(&key_tfm_list_mutex);
 rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
 if (rc)
  printk(KERN_WARNING "One or more global auth toks could not "
         "properly register; rc = [%d]\n", rc);
out:
 return rc;
}

struct kmem_cache *ecryptfs_sb_info_cache;
static struct file_system_type ecryptfs_fs_type;

/*
 * ecryptfs_get_tree
 * @fc: The filesystem context
 */
static int ecryptfs_get_tree(struct fs_context *fc)
{
 struct super_block *s;
 struct ecryptfs_fs_context *ctx = fc->fs_private;
 struct ecryptfs_sb_info *sbi = fc->s_fs_info;
 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 struct ecryptfs_dentry_info *root_info;
 const char *err = "Getting sb failed";
 struct inode *inode;
 struct path path;
 int rc;

 if (!fc->source) {
  rc = -EINVAL;
  err = "Device name cannot be null";
  goto out;
 }

 mount_crypt_stat = &sbi->mount_crypt_stat;
 rc = ecryptfs_validate_options(fc);
 if (rc) {
  err = "Error validating options";
  goto out;
 }

 s = sget_fc(fc, NULL, set_anon_super_fc);
 if (IS_ERR(s)) {
  rc = PTR_ERR(s);
  goto out;
 }

 rc = super_setup_bdi(s);
 if (rc)
  goto out1;

 ecryptfs_set_superblock_private(s, sbi);

 /* ->kill_sb() will take care of sbi after that point */
 sbi = NULL;
 s->s_op = &ecryptfs_sops;
 s->s_xattr = ecryptfs_xattr_handlers;
 set_default_d_op(s, &ecryptfs_dops);

 err = "Reading sb failed";
 rc = kern_path(fc->source, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 if (rc) {
  ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
  goto out1;
 }
 if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
  rc = -EINVAL;
  printk(KERN_ERR "Mount on filesystem of type "
   "eCryptfs explicitly disallowed due to "
   "known incompatibilities\n");
  goto out_free;
 }

 if (is_idmapped_mnt(path.mnt)) {
  rc = -EINVAL;
  printk(KERN_ERR "Mounting on idmapped mounts currently disallowed\n");
  goto out_free;
 }

 if (ctx->check_ruid &&
     !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) {
  rc = -EPERM;
  printk(KERN_ERR "Mount of device (uid: %d) not owned by "
         "requested user (uid: %d)\n",
   i_uid_read(d_inode(path.dentry)),
   from_kuid(&init_user_ns, current_uid()));
  goto out_free;
 }

 ecryptfs_set_superblock_lower(s, path.dentry->d_sb);

 /**
 * Set the POSIX ACL flag based on whether they're enabled in the lower
 * mount.
 */
 s->s_flags = fc->sb_flags & ~SB_POSIXACL;
 s->s_flags |= path.dentry->d_sb->s_flags & SB_POSIXACL;

 /**
 * Force a read-only eCryptfs mount when:
 *   1) The lower mount is ro
 *   2) The ecryptfs_encrypted_view mount option is specified
 */
 if (sb_rdonly(path.dentry->d_sb) || mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
  s->s_flags |= SB_RDONLY;

 s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 s->s_blocksize = path.dentry->d_sb->s_blocksize;
 s->s_magic = ECRYPTFS_SUPER_MAGIC;
 s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;

 rc = -EINVAL;
 if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
  pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
  goto out_free;
 }

 inode = ecryptfs_get_inode(d_inode(path.dentry), s);
 rc = PTR_ERR(inode);
 if (IS_ERR(inode))
  goto out_free;

 s->s_root = d_make_root(inode);
 if (!s->s_root) {
  rc = -ENOMEM;
  goto out_free;
 }

 rc = -ENOMEM;
 root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 if (!root_info)
  goto out_free;

 /* ->kill_sb() will take care of root_info */
 ecryptfs_set_dentry_private(s->s_root, root_info);
 root_info->lower_path = path;

 s->s_flags |= SB_ACTIVE;
 fc->root = dget(s->s_root);
 return 0;

out_free:
 path_put(&path);
out1:
 deactivate_locked_super(s);
out:
 if (sbi)
  ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);

 printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
 return rc;
}

/**
 * ecryptfs_kill_block_super
 * @sb: The ecryptfs super block
 *
 * Used to bring the superblock down and free the private data.
 */
static void ecryptfs_kill_block_super(struct super_block *sb)
{
 struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
 kill_anon_super(sb);
 if (!sb_info)
  return;
 ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
 kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
}

static void ecryptfs_free_fc(struct fs_context *fc)
{
 struct ecryptfs_fs_context *ctx = fc->fs_private;
 struct ecryptfs_sb_info *sbi = fc->s_fs_info;

 kfree(ctx);

 if (sbi) {
  ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
  kmem_cache_free(ecryptfs_sb_info_cache, sbi);
 }
}

static const struct fs_context_operations ecryptfs_context_ops = {
 .free  = ecryptfs_free_fc,
 .parse_param = ecryptfs_parse_param,
 .get_tree = ecryptfs_get_tree,
 .reconfigure = NULL,
};

static int ecryptfs_init_fs_context(struct fs_context *fc)
{
 struct ecryptfs_fs_context *ctx;
 struct ecryptfs_sb_info *sbi = NULL;

 ctx = kzalloc(sizeof(struct ecryptfs_fs_context), GFP_KERNEL);
 if (!ctx)
  return -ENOMEM;
 sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
 if (!sbi) {
  kfree(ctx);
  ctx = NULL;
  return -ENOMEM;
 }

 ecryptfs_init_mount_crypt_stat(&sbi->mount_crypt_stat);

 fc->fs_private = ctx;
 fc->s_fs_info = sbi;
 fc->ops = &ecryptfs_context_ops;
 return 0;
}

static struct file_system_type ecryptfs_fs_type = {
 .owner = THIS_MODULE,
 .name = "ecryptfs",
 .init_fs_context = ecryptfs_init_fs_context,
 .parameters = ecryptfs_fs_param_spec,
 .kill_sb = ecryptfs_kill_block_super,
 .fs_flags = 0
};
MODULE_ALIAS_FS("ecryptfs");

/*
 * inode_info_init_once
 *
 * Initializes the ecryptfs_inode_info_cache when it is created
 */
static void
inode_info_init_once(void *vptr)
{
 struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;

 inode_init_once(&ei->vfs_inode);
}

static struct ecryptfs_cache_info {
 struct kmem_cache **cache;
 const char *name;
 size_t size;
 slab_flags_t flags;
 void (*ctor)(void *obj);
} ecryptfs_cache_infos[] = {
 {
  .cache = &ecryptfs_auth_tok_list_item_cache,
  .name = "ecryptfs_auth_tok_list_item",
  .size = sizeof(struct ecryptfs_auth_tok_list_item),
 },
 {
  .cache = &ecryptfs_file_info_cache,
  .name = "ecryptfs_file_cache",
  .size = sizeof(struct ecryptfs_file_info),
 },
 {
  .cache = &ecryptfs_dentry_info_cache,
  .name = "ecryptfs_dentry_info_cache",
  .size = sizeof(struct ecryptfs_dentry_info),
 },
 {
  .cache = &ecryptfs_inode_info_cache,
  .name = "ecryptfs_inode_cache",
  .size = sizeof(struct ecryptfs_inode_info),
  .flags = SLAB_ACCOUNT,
  .ctor = inode_info_init_once,
 },
 {
  .cache = &ecryptfs_sb_info_cache,
  .name = "ecryptfs_sb_cache",
  .size = sizeof(struct ecryptfs_sb_info),
 },
 {
  .cache = &ecryptfs_header_cache,
  .name = "ecryptfs_headers",
  .size = PAGE_SIZE,
 },
 {
  .cache = &ecryptfs_xattr_cache,
  .name = "ecryptfs_xattr_cache",
  .size = PAGE_SIZE,
 },
 {
  .cache = &ecryptfs_key_record_cache,
  .name = "ecryptfs_key_record_cache",
  .size = sizeof(struct ecryptfs_key_record),
 },
 {
  .cache = &ecryptfs_key_sig_cache,
  .name = "ecryptfs_key_sig_cache",
  .size = sizeof(struct ecryptfs_key_sig),
 },
 {
  .cache = &ecryptfs_global_auth_tok_cache,
  .name = "ecryptfs_global_auth_tok_cache",
  .size = sizeof(struct ecryptfs_global_auth_tok),
 },
 {
  .cache = &ecryptfs_key_tfm_cache,
  .name = "ecryptfs_key_tfm_cache",
  .size = sizeof(struct ecryptfs_key_tfm),
 },
};

static void ecryptfs_free_kmem_caches(void)
{
 int i;

 /*
 * Make sure all delayed rcu free inodes are flushed before we
 * destroy cache.
 */
 rcu_barrier();

 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
  struct ecryptfs_cache_info *info;

  info = &ecryptfs_cache_infos[i];
  kmem_cache_destroy(*(info->cache));
 }
}

/**
 * ecryptfs_init_kmem_caches
 *
 * Returns zero on success; non-zero otherwise
 */
static int ecryptfs_init_kmem_caches(void)
{
 int i;

 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
  struct ecryptfs_cache_info *info;

  info = &ecryptfs_cache_infos[i];
  *(info->cache) = kmem_cache_create(info->name, info->size, 0,
    SLAB_HWCACHE_ALIGN | info->flags, info->ctor);
  if (!*(info->cache)) {
   ecryptfs_free_kmem_caches();
   ecryptfs_printk(KERN_WARNING, "%s: "
     "kmem_cache_create failed\n",
     info->name);
   return -ENOMEM;
  }
 }
 return 0;
}

static struct kobject *ecryptfs_kobj;

static ssize_t version_show(struct kobject *kobj,
       struct kobj_attribute *attr, char *buff)
{
 return sysfs_emit(buff, "%d\n", ECRYPTFS_VERSIONING_MASK);
}

static struct kobj_attribute version_attr = __ATTR_RO(version);

static struct attribute *attributes[] = {
 &version_attr.attr,
 NULL,
};

static const struct attribute_group attr_group = {
 .attrs = attributes,
};

static int do_sysfs_registration(void)
{
 int rc;

 ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 if (!ecryptfs_kobj) {
  printk(KERN_ERR "Unable to create ecryptfs kset\n");
  rc = -ENOMEM;
  goto out;
 }
 rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 if (rc) {
  printk(KERN_ERR
         "Unable to create ecryptfs version attributes\n");
  kobject_put(ecryptfs_kobj);
 }
out:
 return rc;
}

static void do_sysfs_unregistration(void)
{
 sysfs_remove_group(ecryptfs_kobj, &attr_group);
 kobject_put(ecryptfs_kobj);
}

static int __init ecryptfs_init(void)
{
 int rc;

 if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_SIZE) {
  rc = -EINVAL;
  ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
    "larger than the host's page size, and so "
    "eCryptfs cannot run on this system. The "
    "default eCryptfs extent size is [%u] bytes; "
    "the page size is [%lu] bytes.\n",
    ECRYPTFS_DEFAULT_EXTENT_SIZE,
    (unsigned long)PAGE_SIZE);
  goto out;
 }
 rc = ecryptfs_init_kmem_caches();
 if (rc) {
  printk(KERN_ERR
         "Failed to allocate one or more kmem_cache objects\n");
  goto out;
 }
 rc = do_sysfs_registration();
 if (rc) {
  printk(KERN_ERR "sysfs registration failed\n");
  goto out_free_kmem_caches;
 }
 rc = ecryptfs_init_kthread();
 if (rc) {
  printk(KERN_ERR "%s: kthread initialization failed; "
         "rc = [%d]\n", __func__, rc);
  goto out_do_sysfs_unregistration;
 }
 rc = ecryptfs_init_messaging();
 if (rc) {
  printk(KERN_ERR "Failure occurred while attempting to "
    "initialize the communications channel to "
    "ecryptfsd\n");
  goto out_destroy_kthread;
 }
 rc = ecryptfs_init_crypto();
 if (rc) {
  printk(KERN_ERR "Failure whilst attempting to init crypto; "
         "rc = [%d]\n", rc);
  goto out_release_messaging;
 }
 rc = register_filesystem(&ecryptfs_fs_type);
 if (rc) {
  printk(KERN_ERR "Failed to register filesystem\n");
  goto out_destroy_crypto;
 }
 if (ecryptfs_verbosity > 0)
  printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
   "will be written to the syslog!\n", ecryptfs_verbosity);

 goto out;
out_destroy_crypto:
 ecryptfs_destroy_crypto();
out_release_messaging:
 ecryptfs_release_messaging();
out_destroy_kthread:
 ecryptfs_destroy_kthread();
out_do_sysfs_unregistration:
 do_sysfs_unregistration();
out_free_kmem_caches:
 ecryptfs_free_kmem_caches();
out:
 return rc;
}

static void __exit ecryptfs_exit(void)
{
 int rc;

 rc = ecryptfs_destroy_crypto();
 if (rc)
  printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
         "rc = [%d]\n", rc);
 ecryptfs_release_messaging();
 ecryptfs_destroy_kthread();
 do_sysfs_unregistration();
 unregister_filesystem(&ecryptfs_fs_type);
 ecryptfs_free_kmem_caches();
}

MODULE_AUTHOR("Michael A. Halcrow ");
MODULE_DESCRIPTION("eCryptfs");

MODULE_LICENSE("GPL");

module_init(ecryptfs_init)
module_exit(ecryptfs_exit)