fs/ecryptfs/ecryptfs_kernel.h

   1 /**
   2  * eCryptfs: Linux filesystem encryption layer
   3  * Kernel declarations.
   4  *
   5  * Copyright (C) 1997-2003 Erez Zadok
   6  * Copyright (C) 2001-2003 Stony Brook University
   7  * Copyright (C) 2004-2006 International Business Machines Corp.
   8  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation; either version 2 of the
  13  * License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  23  * 02111-1307, USA.
  24  */
  25
  26 #ifndef ECRYPTFS_KERNEL_H
  27 #define ECRYPTFS_KERNEL_H
  28
  29 #include <keys/user-type.h>
  30 #include <linux/fs.h>
  31 #include <linux/fs_stack.h>
  32 #include <linux/namei.h>
  33 #include <linux/scatterlist.h>
  34
  35 /* Version verification for shared data structures w/ userspace */
  36 #define ECRYPTFS_VERSION_MAJOR 0x00
  37 #define ECRYPTFS_VERSION_MINOR 0x04
  38 #define ECRYPTFS_SUPPORTED_FILE_VERSION 0x01
  39 /* These flags indicate which features are supported by the kernel
  40  * module; userspace tools such as the mount helper read
  41  * ECRYPTFS_VERSIONING_MASK from a sysfs handle in order to determine
  42  * how to behave. */
  43 #define ECRYPTFS_VERSIONING_PASSPHRASE 0x00000001
  44 #define ECRYPTFS_VERSIONING_PUBKEY 0x00000002
  45 #define ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH 0x00000004
  46 #define ECRYPTFS_VERSIONING_POLICY 0x00000008
  47 #define ECRYPTFS_VERSIONING_MASK (ECRYPTFS_VERSIONING_PASSPHRASE \
  48                                   | ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH)
  49
  50 #define ECRYPTFS_MAX_PASSWORD_LENGTH 64
  51 #define ECRYPTFS_MAX_PASSPHRASE_BYTES ECRYPTFS_MAX_PASSWORD_LENGTH
  52 #define ECRYPTFS_SALT_SIZE 8
  53 #define ECRYPTFS_SALT_SIZE_HEX (ECRYPTFS_SALT_SIZE*2)
  54 /* The original signature size is only for what is stored on disk; all
  55  * in-memory representations are expanded hex, so it better adapted to
  56  * be passed around or referenced on the command line */
  57 #define ECRYPTFS_SIG_SIZE 8
  58 #define ECRYPTFS_SIG_SIZE_HEX (ECRYPTFS_SIG_SIZE*2)
  59 #define ECRYPTFS_PASSWORD_SIG_SIZE ECRYPTFS_SIG_SIZE_HEX
  60 #define ECRYPTFS_MAX_KEY_BYTES 64
  61 #define ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES 512
  62 #define ECRYPTFS_DEFAULT_IV_BYTES 16
  63 #define ECRYPTFS_FILE_VERSION 0x01
  64 #define ECRYPTFS_DEFAULT_HEADER_EXTENT_SIZE 8192
  65 #define ECRYPTFS_DEFAULT_EXTENT_SIZE 4096
  66 #define ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE 8192
  67
  68 #define RFC2440_CIPHER_DES3_EDE 0x02
  69 #define RFC2440_CIPHER_CAST_5 0x03
  70 #define RFC2440_CIPHER_BLOWFISH 0x04
  71 #define RFC2440_CIPHER_AES_128 0x07
  72 #define RFC2440_CIPHER_AES_192 0x08
  73 #define RFC2440_CIPHER_AES_256 0x09
  74 #define RFC2440_CIPHER_TWOFISH 0x0a
  75 #define RFC2440_CIPHER_CAST_6 0x0b
  76
  77 #define ECRYPTFS_SET_FLAG(flag_bit_vector, flag) (flag_bit_vector |= (flag))
  78 #define ECRYPTFS_CLEAR_FLAG(flag_bit_vector, flag) (flag_bit_vector &= ~(flag))
  79 #define ECRYPTFS_CHECK_FLAG(flag_bit_vector, flag) (flag_bit_vector & (flag))
  80
  81 /**
  82  * For convenience, we may need to pass around the encrypted session
  83  * key between kernel and userspace because the authentication token
  84  * may not be extractable.  For example, the TPM may not release the
  85  * private key, instead requiring the encrypted data and returning the
  86  * decrypted data.
  87  */
  88 struct ecryptfs_session_key {
  89 #define ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT 0x00000001
  90 #define ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT 0x00000002
  91 #define ECRYPTFS_CONTAINS_DECRYPTED_KEY 0x00000004
  92 #define ECRYPTFS_CONTAINS_ENCRYPTED_KEY 0x00000008
  93         u32 flags;
  94         u32 encrypted_key_size;
  95         u32 decrypted_key_size;
  96         u8 encrypted_key[ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES];
  97         u8 decrypted_key[ECRYPTFS_MAX_KEY_BYTES];
  98 };
  99
 100 struct ecryptfs_password {
 101         u32 password_bytes;
 102         s32 hash_algo;
 103         u32 hash_iterations;
 104         u32 session_key_encryption_key_bytes;
 105 #define ECRYPTFS_PERSISTENT_PASSWORD 0x01
 106 #define ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET 0x02
 107         u32 flags;
 108         /* Iterated-hash concatenation of salt and passphrase */
 109         u8 session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
 110         u8 signature[ECRYPTFS_PASSWORD_SIG_SIZE + 1];
 111         /* Always in expanded hex */
 112         u8 salt[ECRYPTFS_SALT_SIZE];
 113 };
 114
 115 enum ecryptfs_token_types {ECRYPTFS_PASSWORD, ECRYPTFS_PRIVATE_KEY};
 116
 117 /* May be a password or a private key */
 118 struct ecryptfs_auth_tok {
 119         u16 version; /* 8-bit major and 8-bit minor */
 120         u16 token_type;
 121         u32 flags;
 122         struct ecryptfs_session_key session_key;
 123         u8 reserved[32];
 124         union {
 125                 struct ecryptfs_password password;
 126                 /* Private key is in future eCryptfs releases */
 127         } token;
 128 } __attribute__ ((packed));
 129
 130 void ecryptfs_dump_auth_tok(struct ecryptfs_auth_tok *auth_tok);
 131 extern void ecryptfs_to_hex(char *dst, char *src, size_t src_size);
 132 extern void ecryptfs_from_hex(char *dst, char *src, int dst_size);
 133
 134 struct ecryptfs_key_record {
 135         unsigned char type;
 136         size_t enc_key_size;
 137         unsigned char sig[ECRYPTFS_SIG_SIZE];
 138         unsigned char enc_key[ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES];
 139 };
 140
 141 struct ecryptfs_auth_tok_list {
 142         struct ecryptfs_auth_tok *auth_tok;
 143         struct list_head list;
 144 };
 145
 146 struct ecryptfs_crypt_stat;
 147 struct ecryptfs_mount_crypt_stat;
 148
 149 struct ecryptfs_page_crypt_context {
 150         struct page *page;
 151 #define ECRYPTFS_PREPARE_COMMIT_MODE 0
 152 #define ECRYPTFS_WRITEPAGE_MODE      1
 153         unsigned int mode;
 154         union {
 155                 struct file *lower_file;
 156                 struct writeback_control *wbc;
 157         } param;
 158 };
 159
 160 static inline struct ecryptfs_auth_tok *
 161 ecryptfs_get_key_payload_data(struct key *key)
 162 {
 163         return (struct ecryptfs_auth_tok *)
 164                 (((struct user_key_payload*)key->payload.data)->data);
 165 }
 166
 167 #define ECRYPTFS_SUPER_MAGIC 0xf15f
 168 #define ECRYPTFS_MAX_KEYSET_SIZE 1024
 169 #define ECRYPTFS_MAX_CIPHER_NAME_SIZE 32
 170 #define ECRYPTFS_MAX_NUM_ENC_KEYS 64
 171 #define ECRYPTFS_MAX_NUM_KEYSIGS 2 /* TODO: Make this a linked list */
 172 #define ECRYPTFS_MAX_IV_BYTES 16        /* 128 bits */
 173 #define ECRYPTFS_SALT_BYTES 2
 174 #define MAGIC_ECRYPTFS_MARKER 0x3c81b7f5
 175 #define MAGIC_ECRYPTFS_MARKER_SIZE_BYTES 8      /* 4*2 */
 176 #define ECRYPTFS_FILE_SIZE_BYTES 8
 177 #define ECRYPTFS_DEFAULT_CIPHER "aes"
 178 #define ECRYPTFS_DEFAULT_KEY_BYTES 16
 179 #define ECRYPTFS_DEFAULT_CHAINING_MODE CRYPTO_TFM_MODE_CBC
 180 #define ECRYPTFS_DEFAULT_HASH "md5"
 181 #define ECRYPTFS_TAG_3_PACKET_TYPE 0x8C
 182 #define ECRYPTFS_TAG_11_PACKET_TYPE 0xED
 183 #define MD5_DIGEST_SIZE 16
 184
 185 /**
 186  * This is the primary struct associated with each encrypted file.
 187  *
 188  * TODO: cache align/pack?
 189  */
 190 struct ecryptfs_crypt_stat {
 191 #define ECRYPTFS_STRUCT_INITIALIZED 0x00000001
 192 #define ECRYPTFS_POLICY_APPLIED     0x00000002
 193 #define ECRYPTFS_NEW_FILE           0x00000004
 194 #define ECRYPTFS_ENCRYPTED          0x00000008
 195 #define ECRYPTFS_SECURITY_WARNING   0x00000010
 196 #define ECRYPTFS_ENABLE_HMAC        0x00000020
 197 #define ECRYPTFS_ENCRYPT_IV_PAGES   0x00000040
 198 #define ECRYPTFS_KEY_VALID          0x00000080
 199         u32 flags;
 200         unsigned int file_version;
 201         size_t iv_bytes;
 202         size_t num_keysigs;
 203         size_t header_extent_size;
 204         size_t num_header_extents_at_front;
 205         size_t extent_size; /* Data extent size; default is 4096 */
 206         size_t key_size;
 207         size_t extent_shift;
 208         unsigned int extent_mask;
 209         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 210         struct crypto_blkcipher *tfm;
 211         struct crypto_hash *hash_tfm; /* Crypto context for generating
 212                                        * the initialization vectors */
 213         unsigned char cipher[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
 214         unsigned char key[ECRYPTFS_MAX_KEY_BYTES];
 215         unsigned char root_iv[ECRYPTFS_MAX_IV_BYTES];
 216         unsigned char keysigs[ECRYPTFS_MAX_NUM_KEYSIGS][ECRYPTFS_SIG_SIZE_HEX];
 217         struct mutex cs_tfm_mutex;
 218         struct mutex cs_hash_tfm_mutex;
 219         struct mutex cs_mutex;
 220 };
 221
 222 /* inode private data. */
 223 struct ecryptfs_inode_info {
 224         struct inode vfs_inode;
 225         struct inode *wii_inode;
 226         struct ecryptfs_crypt_stat crypt_stat;
 227 };
 228
 229 /* dentry private data. Each dentry must keep track of a lower
 230  * vfsmount too. */
 231 struct ecryptfs_dentry_info {
 232         struct path lower_path;
 233         struct ecryptfs_crypt_stat *crypt_stat;
 234 };
 235
 236 /**
 237  * This struct is to enable a mount-wide passphrase/salt combo. This
 238  * is more or less a stopgap to provide similar functionality to other
 239  * crypto filesystems like EncFS or CFS until full policy support is
 240  * implemented in eCryptfs.
 241  */
 242 struct ecryptfs_mount_crypt_stat {
 243         /* Pointers to memory we do not own, do not free these */
 244 #define ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED 0x00000001
 245         u32 flags;
 246         struct ecryptfs_auth_tok *global_auth_tok;
 247         struct key *global_auth_tok_key;
 248         size_t global_default_cipher_key_size;
 249         struct crypto_blkcipher *global_key_tfm;
 250         struct mutex global_key_tfm_mutex;
 251         unsigned char global_default_cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE
 252                                                  + 1];
 253         unsigned char global_auth_tok_sig[ECRYPTFS_SIG_SIZE_HEX + 1];
 254 };
 255
 256 /* superblock private data. */
 257 struct ecryptfs_sb_info {
 258         struct super_block *wsi_sb;
 259         struct ecryptfs_mount_crypt_stat mount_crypt_stat;
 260 };
 261
 262 /* file private data. */
 263 struct ecryptfs_file_info {
 264         struct file *wfi_file;
 265         struct ecryptfs_crypt_stat *crypt_stat;
 266 };
 267
 268 /* auth_tok <=> encrypted_session_key mappings */
 269 struct ecryptfs_auth_tok_list_item {
 270         unsigned char encrypted_session_key[ECRYPTFS_MAX_KEY_BYTES];
 271         struct list_head list;
 272         struct ecryptfs_auth_tok auth_tok;
 273 };
 274
 275 static inline struct ecryptfs_file_info *
 276 ecryptfs_file_to_private(struct file *file)
 277 {
 278         return (struct ecryptfs_file_info *)file->private_data;
 279 }
 280
 281 static inline void
 282 ecryptfs_set_file_private(struct file *file,
 283                           struct ecryptfs_file_info *file_info)
 284 {
 285         file->private_data = file_info;
 286 }
 287
 288 static inline struct file *ecryptfs_file_to_lower(struct file *file)
 289 {
 290         return ((struct ecryptfs_file_info *)file->private_data)->wfi_file;
 291 }
 292
 293 static inline void
 294 ecryptfs_set_file_lower(struct file *file, struct file *lower_file)
 295 {
 296         ((struct ecryptfs_file_info *)file->private_data)->wfi_file =
 297                 lower_file;
 298 }
 299
 300 static inline struct ecryptfs_inode_info *
 301 ecryptfs_inode_to_private(struct inode *inode)
 302 {
 303         return container_of(inode, struct ecryptfs_inode_info, vfs_inode);
 304 }
 305
 306 static inline struct inode *ecryptfs_inode_to_lower(struct inode *inode)
 307 {
 308         return ecryptfs_inode_to_private(inode)->wii_inode;
 309 }
 310
 311 static inline void
 312 ecryptfs_set_inode_lower(struct inode *inode, struct inode *lower_inode)
 313 {
 314         ecryptfs_inode_to_private(inode)->wii_inode = lower_inode;
 315 }
 316
 317 static inline struct ecryptfs_sb_info *
 318 ecryptfs_superblock_to_private(struct super_block *sb)
 319 {
 320         return (struct ecryptfs_sb_info *)sb->s_fs_info;
 321 }
 322
 323 static inline void
 324 ecryptfs_set_superblock_private(struct super_block *sb,
 325                                 struct ecryptfs_sb_info *sb_info)
 326 {
 327         sb->s_fs_info = sb_info;
 328 }
 329
 330 static inline struct super_block *
 331 ecryptfs_superblock_to_lower(struct super_block *sb)
 332 {
 333         return ((struct ecryptfs_sb_info *)sb->s_fs_info)->wsi_sb;
 334 }
 335
 336 static inline void
 337 ecryptfs_set_superblock_lower(struct super_block *sb,
 338                               struct super_block *lower_sb)
 339 {
 340         ((struct ecryptfs_sb_info *)sb->s_fs_info)->wsi_sb = lower_sb;
 341 }
 342
 343 static inline struct ecryptfs_dentry_info *
 344 ecryptfs_dentry_to_private(struct dentry *dentry)
 345 {
 346         return (struct ecryptfs_dentry_info *)dentry->d_fsdata;
 347 }
 348
 349 static inline void
 350 ecryptfs_set_dentry_private(struct dentry *dentry,
 351                             struct ecryptfs_dentry_info *dentry_info)
 352 {
 353         dentry->d_fsdata = dentry_info;
 354 }
 355
 356 static inline struct dentry *
 357 ecryptfs_dentry_to_lower(struct dentry *dentry)
 358 {
 359         return ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.dentry;
 360 }
 361
 362 static inline void
 363 ecryptfs_set_dentry_lower(struct dentry *dentry, struct dentry *lower_dentry)
 364 {
 365         ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.dentry =
 366                 lower_dentry;
 367 }
 368
 369 static inline struct vfsmount *
 370 ecryptfs_dentry_to_lower_mnt(struct dentry *dentry)
 371 {
 372         return ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.mnt;
 373 }
 374
 375 static inline void
 376 ecryptfs_set_dentry_lower_mnt(struct dentry *dentry, struct vfsmount *lower_mnt)
 377 {
 378         ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.mnt =
 379                 lower_mnt;
 380 }
 381
 382 #define ecryptfs_printk(type, fmt, arg...) \
 383         __ecryptfs_printk(type "%s: " fmt, __FUNCTION__, ## arg);
 384 void __ecryptfs_printk(const char *fmt, ...);
 385
 386 extern const struct file_operations ecryptfs_main_fops;
 387 extern const struct file_operations ecryptfs_dir_fops;
 388 extern struct inode_operations ecryptfs_main_iops;
 389 extern struct inode_operations ecryptfs_dir_iops;
 390 extern struct inode_operations ecryptfs_symlink_iops;
 391 extern struct super_operations ecryptfs_sops;
 392 extern struct dentry_operations ecryptfs_dops;
 393 extern struct address_space_operations ecryptfs_aops;
 394 extern int ecryptfs_verbosity;
 395
 396 extern struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
 397 extern struct kmem_cache *ecryptfs_file_info_cache;
 398 extern struct kmem_cache *ecryptfs_dentry_info_cache;
 399 extern struct kmem_cache *ecryptfs_inode_info_cache;
 400 extern struct kmem_cache *ecryptfs_sb_info_cache;
 401 extern struct kmem_cache *ecryptfs_header_cache_0;
 402 extern struct kmem_cache *ecryptfs_header_cache_1;
 403 extern struct kmem_cache *ecryptfs_header_cache_2;
 404 extern struct kmem_cache *ecryptfs_lower_page_cache;
 405
 406 int ecryptfs_interpose(struct dentry *hidden_dentry,
 407                        struct dentry *this_dentry, struct super_block *sb,
 408                        int flag);
 409 int ecryptfs_fill_zeros(struct file *file, loff_t new_length);
 410 int ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat,
 411                              const char *name, int length,
 412                              char **decrypted_name);
 413 int ecryptfs_encode_filename(struct ecryptfs_crypt_stat *crypt_stat,
 414                              const char *name, int length,
 415                              char **encoded_name);
 416 struct dentry *ecryptfs_lower_dentry(struct dentry *this_dentry);
 417 void ecryptfs_dump_hex(char *data, int bytes);
 418 int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
 419                         int sg_size);
 420 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat);
 421 void ecryptfs_rotate_iv(unsigned char *iv);
 422 void ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat);
 423 void ecryptfs_destruct_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat);
 424 void ecryptfs_destruct_mount_crypt_stat(
 425         struct ecryptfs_mount_crypt_stat *mount_crypt_stat);
 426 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat);
 427 int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
 428                                            char *cipher_name,
 429                                            char *chaining_modifier);
 430 int ecryptfs_write_inode_size_to_header(struct file *lower_file,
 431                                         struct inode *lower_inode,
 432                                         struct inode *inode);
 433 int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode,
 434                             struct file *lower_file,
 435                             unsigned long lower_page_index, int byte_offset,
 436                             int region_bytes);
 437 int
 438 ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode,
 439                            struct file *lower_file, int byte_offset,
 440                            int region_size);
 441 int ecryptfs_copy_page_to_lower(struct page *page, struct inode *lower_inode,
 442                                 struct file *lower_file);
 443 int ecryptfs_do_readpage(struct file *file, struct page *page,
 444                          pgoff_t lower_page_index);
 445 int ecryptfs_grab_and_map_lower_page(struct page **lower_page,
 446                                      char **lower_virt,
 447                                      struct inode *lower_inode,
 448                                      unsigned long lower_page_index);
 449 int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
 450                                               struct inode *lower_inode,
 451                                               struct writeback_control *wbc);
 452 int ecryptfs_encrypt_page(struct ecryptfs_page_crypt_context *ctx);
 453 int ecryptfs_decrypt_page(struct file *file, struct page *page);
 454 int ecryptfs_write_headers(struct dentry *ecryptfs_dentry,
 455                            struct file *lower_file);
 456 int ecryptfs_write_headers_virt(char *page_virt,
 457                                 struct ecryptfs_crypt_stat *crypt_stat,
 458                                 struct dentry *ecryptfs_dentry);
 459 int ecryptfs_read_headers(struct dentry *ecryptfs_dentry,
 460                           struct file *lower_file);
 461 int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry);
 462 int contains_ecryptfs_marker(char *data);
 463 int ecryptfs_read_header_region(char *data, struct dentry *dentry,
 464                                 struct vfsmount *mnt);
 465 u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat);
 466 int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code);
 467 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat);
 468 int ecryptfs_generate_key_packet_set(char *dest_base,
 469                                      struct ecryptfs_crypt_stat *crypt_stat,
 470                                      struct dentry *ecryptfs_dentry,
 471                                      size_t *len, size_t max);
 472 int process_request_key_err(long err_code);
 473 int
 474 ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
 475                           unsigned char *src, struct dentry *ecryptfs_dentry);
 476 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length);
 477 int
 478 ecryptfs_process_cipher(struct crypto_blkcipher **key_tfm, char *cipher_name,
 479                         size_t *key_size);
 480 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode);
 481 int ecryptfs_inode_set(struct inode *inode, void *lower_inode);
 482 void ecryptfs_init_inode(struct inode *inode, struct inode *lower_inode);
 483 int ecryptfs_open_lower_file(struct file **lower_file,
 484                              struct dentry *lower_dentry,
 485                              struct vfsmount *lower_mnt, int flags);
 486 int ecryptfs_close_lower_file(struct file *lower_file);
 487
 488 #endif /* #ifndef ECRYPTFS_KERNEL_H */