2 * eCryptfs: Linux filesystem encryption layer
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>
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.
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.
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
26 #ifndef ECRYPTFS_KERNEL_H
27 #define ECRYPTFS_KERNEL_H
29 #include <keys/user-type.h>
31 #include <linux/fs_stack.h>
32 #include <linux/namei.h>
33 #include <linux/scatterlist.h>
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
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)
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
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
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))
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
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
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
];
100 struct ecryptfs_password
{
104 u32 session_key_encryption_key_bytes
;
105 #define ECRYPTFS_PERSISTENT_PASSWORD 0x01
106 #define ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET 0x02
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
];
115 enum ecryptfs_token_types
{ECRYPTFS_PASSWORD
, ECRYPTFS_PRIVATE_KEY
};
117 /* May be a password or a private key */
118 struct ecryptfs_auth_tok
{
119 u16 version
; /* 8-bit major and 8-bit minor */
122 struct ecryptfs_session_key session_key
;
125 struct ecryptfs_password password
;
126 /* Private key is in future eCryptfs releases */
128 } __attribute__ ((packed
));
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
);
134 struct ecryptfs_key_record
{
137 unsigned char sig
[ECRYPTFS_SIG_SIZE
];
138 unsigned char enc_key
[ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
];
141 struct ecryptfs_auth_tok_list
{
142 struct ecryptfs_auth_tok
*auth_tok
;
143 struct list_head list
;
146 struct ecryptfs_crypt_stat
;
147 struct ecryptfs_mount_crypt_stat
;
149 struct ecryptfs_page_crypt_context
{
151 #define ECRYPTFS_PREPARE_COMMIT_MODE 0
152 #define ECRYPTFS_WRITEPAGE_MODE 1
155 struct file
*lower_file
;
156 struct writeback_control
*wbc
;
160 static inline struct ecryptfs_auth_tok
*
161 ecryptfs_get_key_payload_data(struct key
*key
)
163 return (struct ecryptfs_auth_tok
*)
164 (((struct user_key_payload
*)key
->payload
.data
)->data
);
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_HASH "md5"
180 #define ECRYPTFS_TAG_3_PACKET_TYPE 0x8C
181 #define ECRYPTFS_TAG_11_PACKET_TYPE 0xED
182 #define MD5_DIGEST_SIZE 16
185 * This is the primary struct associated with each encrypted file.
187 * TODO: cache align/pack?
189 struct ecryptfs_crypt_stat
{
190 #define ECRYPTFS_STRUCT_INITIALIZED 0x00000001
191 #define ECRYPTFS_POLICY_APPLIED 0x00000002
192 #define ECRYPTFS_NEW_FILE 0x00000004
193 #define ECRYPTFS_ENCRYPTED 0x00000008
194 #define ECRYPTFS_SECURITY_WARNING 0x00000010
195 #define ECRYPTFS_ENABLE_HMAC 0x00000020
196 #define ECRYPTFS_ENCRYPT_IV_PAGES 0x00000040
197 #define ECRYPTFS_KEY_VALID 0x00000080
199 unsigned int file_version
;
202 size_t header_extent_size
;
203 size_t num_header_extents_at_front
;
204 size_t extent_size
; /* Data extent size; default is 4096 */
207 unsigned int extent_mask
;
208 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
;
209 struct crypto_blkcipher
*tfm
;
210 struct crypto_hash
*hash_tfm
; /* Crypto context for generating
211 * the initialization vectors */
212 unsigned char cipher
[ECRYPTFS_MAX_CIPHER_NAME_SIZE
];
213 unsigned char key
[ECRYPTFS_MAX_KEY_BYTES
];
214 unsigned char root_iv
[ECRYPTFS_MAX_IV_BYTES
];
215 unsigned char keysigs
[ECRYPTFS_MAX_NUM_KEYSIGS
][ECRYPTFS_SIG_SIZE_HEX
];
216 struct mutex cs_tfm_mutex
;
217 struct mutex cs_hash_tfm_mutex
;
218 struct mutex cs_mutex
;
221 /* inode private data. */
222 struct ecryptfs_inode_info
{
223 struct inode vfs_inode
;
224 struct inode
*wii_inode
;
225 struct ecryptfs_crypt_stat crypt_stat
;
228 /* dentry private data. Each dentry must keep track of a lower
230 struct ecryptfs_dentry_info
{
231 struct path lower_path
;
232 struct ecryptfs_crypt_stat
*crypt_stat
;
236 * This struct is to enable a mount-wide passphrase/salt combo. This
237 * is more or less a stopgap to provide similar functionality to other
238 * crypto filesystems like EncFS or CFS until full policy support is
239 * implemented in eCryptfs.
241 struct ecryptfs_mount_crypt_stat
{
242 /* Pointers to memory we do not own, do not free these */
243 #define ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED 0x00000001
245 struct ecryptfs_auth_tok
*global_auth_tok
;
246 struct key
*global_auth_tok_key
;
247 size_t global_default_cipher_key_size
;
248 struct crypto_blkcipher
*global_key_tfm
;
249 struct mutex global_key_tfm_mutex
;
250 unsigned char global_default_cipher_name
[ECRYPTFS_MAX_CIPHER_NAME_SIZE
252 unsigned char global_auth_tok_sig
[ECRYPTFS_SIG_SIZE_HEX
+ 1];
255 /* superblock private data. */
256 struct ecryptfs_sb_info
{
257 struct super_block
*wsi_sb
;
258 struct ecryptfs_mount_crypt_stat mount_crypt_stat
;
261 /* file private data. */
262 struct ecryptfs_file_info
{
263 struct file
*wfi_file
;
264 struct ecryptfs_crypt_stat
*crypt_stat
;
267 /* auth_tok <=> encrypted_session_key mappings */
268 struct ecryptfs_auth_tok_list_item
{
269 unsigned char encrypted_session_key
[ECRYPTFS_MAX_KEY_BYTES
];
270 struct list_head list
;
271 struct ecryptfs_auth_tok auth_tok
;
274 static inline struct ecryptfs_file_info
*
275 ecryptfs_file_to_private(struct file
*file
)
277 return (struct ecryptfs_file_info
*)file
->private_data
;
281 ecryptfs_set_file_private(struct file
*file
,
282 struct ecryptfs_file_info
*file_info
)
284 file
->private_data
= file_info
;
287 static inline struct file
*ecryptfs_file_to_lower(struct file
*file
)
289 return ((struct ecryptfs_file_info
*)file
->private_data
)->wfi_file
;
293 ecryptfs_set_file_lower(struct file
*file
, struct file
*lower_file
)
295 ((struct ecryptfs_file_info
*)file
->private_data
)->wfi_file
=
299 static inline struct ecryptfs_inode_info
*
300 ecryptfs_inode_to_private(struct inode
*inode
)
302 return container_of(inode
, struct ecryptfs_inode_info
, vfs_inode
);
305 static inline struct inode
*ecryptfs_inode_to_lower(struct inode
*inode
)
307 return ecryptfs_inode_to_private(inode
)->wii_inode
;
311 ecryptfs_set_inode_lower(struct inode
*inode
, struct inode
*lower_inode
)
313 ecryptfs_inode_to_private(inode
)->wii_inode
= lower_inode
;
316 static inline struct ecryptfs_sb_info
*
317 ecryptfs_superblock_to_private(struct super_block
*sb
)
319 return (struct ecryptfs_sb_info
*)sb
->s_fs_info
;
323 ecryptfs_set_superblock_private(struct super_block
*sb
,
324 struct ecryptfs_sb_info
*sb_info
)
326 sb
->s_fs_info
= sb_info
;
329 static inline struct super_block
*
330 ecryptfs_superblock_to_lower(struct super_block
*sb
)
332 return ((struct ecryptfs_sb_info
*)sb
->s_fs_info
)->wsi_sb
;
336 ecryptfs_set_superblock_lower(struct super_block
*sb
,
337 struct super_block
*lower_sb
)
339 ((struct ecryptfs_sb_info
*)sb
->s_fs_info
)->wsi_sb
= lower_sb
;
342 static inline struct ecryptfs_dentry_info
*
343 ecryptfs_dentry_to_private(struct dentry
*dentry
)
345 return (struct ecryptfs_dentry_info
*)dentry
->d_fsdata
;
349 ecryptfs_set_dentry_private(struct dentry
*dentry
,
350 struct ecryptfs_dentry_info
*dentry_info
)
352 dentry
->d_fsdata
= dentry_info
;
355 static inline struct dentry
*
356 ecryptfs_dentry_to_lower(struct dentry
*dentry
)
358 return ((struct ecryptfs_dentry_info
*)dentry
->d_fsdata
)->lower_path
.dentry
;
362 ecryptfs_set_dentry_lower(struct dentry
*dentry
, struct dentry
*lower_dentry
)
364 ((struct ecryptfs_dentry_info
*)dentry
->d_fsdata
)->lower_path
.dentry
=
368 static inline struct vfsmount
*
369 ecryptfs_dentry_to_lower_mnt(struct dentry
*dentry
)
371 return ((struct ecryptfs_dentry_info
*)dentry
->d_fsdata
)->lower_path
.mnt
;
375 ecryptfs_set_dentry_lower_mnt(struct dentry
*dentry
, struct vfsmount
*lower_mnt
)
377 ((struct ecryptfs_dentry_info
*)dentry
->d_fsdata
)->lower_path
.mnt
=
381 #define ecryptfs_printk(type, fmt, arg...) \
382 __ecryptfs_printk(type "%s: " fmt, __FUNCTION__, ## arg);
383 void __ecryptfs_printk(const char *fmt
, ...);
385 extern const struct file_operations ecryptfs_main_fops
;
386 extern const struct file_operations ecryptfs_dir_fops
;
387 extern struct inode_operations ecryptfs_main_iops
;
388 extern struct inode_operations ecryptfs_dir_iops
;
389 extern struct inode_operations ecryptfs_symlink_iops
;
390 extern struct super_operations ecryptfs_sops
;
391 extern struct dentry_operations ecryptfs_dops
;
392 extern struct address_space_operations ecryptfs_aops
;
393 extern int ecryptfs_verbosity
;
395 extern struct kmem_cache
*ecryptfs_auth_tok_list_item_cache
;
396 extern struct kmem_cache
*ecryptfs_file_info_cache
;
397 extern struct kmem_cache
*ecryptfs_dentry_info_cache
;
398 extern struct kmem_cache
*ecryptfs_inode_info_cache
;
399 extern struct kmem_cache
*ecryptfs_sb_info_cache
;
400 extern struct kmem_cache
*ecryptfs_header_cache_0
;
401 extern struct kmem_cache
*ecryptfs_header_cache_1
;
402 extern struct kmem_cache
*ecryptfs_header_cache_2
;
403 extern struct kmem_cache
*ecryptfs_lower_page_cache
;
405 int ecryptfs_interpose(struct dentry
*hidden_dentry
,
406 struct dentry
*this_dentry
, struct super_block
*sb
,
408 int ecryptfs_fill_zeros(struct file
*file
, loff_t new_length
);
409 int ecryptfs_decode_filename(struct ecryptfs_crypt_stat
*crypt_stat
,
410 const char *name
, int length
,
411 char **decrypted_name
);
412 int ecryptfs_encode_filename(struct ecryptfs_crypt_stat
*crypt_stat
,
413 const char *name
, int length
,
414 char **encoded_name
);
415 struct dentry
*ecryptfs_lower_dentry(struct dentry
*this_dentry
);
416 void ecryptfs_dump_hex(char *data
, int bytes
);
417 int virt_to_scatterlist(const void *addr
, int size
, struct scatterlist
*sg
,
419 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat
*crypt_stat
);
420 void ecryptfs_rotate_iv(unsigned char *iv
);
421 void ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat
*crypt_stat
);
422 void ecryptfs_destruct_crypt_stat(struct ecryptfs_crypt_stat
*crypt_stat
);
423 void ecryptfs_destruct_mount_crypt_stat(
424 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
);
425 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat
*crypt_stat
);
426 int ecryptfs_crypto_api_algify_cipher_name(char **algified_name
,
428 char *chaining_modifier
);
429 int ecryptfs_write_inode_size_to_header(struct file
*lower_file
,
430 struct inode
*lower_inode
,
431 struct inode
*inode
);
432 int ecryptfs_get_lower_page(struct page
**lower_page
, struct inode
*lower_inode
,
433 struct file
*lower_file
,
434 unsigned long lower_page_index
, int byte_offset
,
437 ecryptfs_commit_lower_page(struct page
*lower_page
, struct inode
*lower_inode
,
438 struct file
*lower_file
, int byte_offset
,
440 int ecryptfs_copy_page_to_lower(struct page
*page
, struct inode
*lower_inode
,
441 struct file
*lower_file
);
442 int ecryptfs_do_readpage(struct file
*file
, struct page
*page
,
443 pgoff_t lower_page_index
);
444 int ecryptfs_grab_and_map_lower_page(struct page
**lower_page
,
446 struct inode
*lower_inode
,
447 unsigned long lower_page_index
);
448 int ecryptfs_writepage_and_release_lower_page(struct page
*lower_page
,
449 struct inode
*lower_inode
,
450 struct writeback_control
*wbc
);
451 int ecryptfs_encrypt_page(struct ecryptfs_page_crypt_context
*ctx
);
452 int ecryptfs_decrypt_page(struct file
*file
, struct page
*page
);
453 int ecryptfs_write_headers(struct dentry
*ecryptfs_dentry
,
454 struct file
*lower_file
);
455 int ecryptfs_write_headers_virt(char *page_virt
,
456 struct ecryptfs_crypt_stat
*crypt_stat
,
457 struct dentry
*ecryptfs_dentry
);
458 int ecryptfs_read_headers(struct dentry
*ecryptfs_dentry
,
459 struct file
*lower_file
);
460 int ecryptfs_new_file_context(struct dentry
*ecryptfs_dentry
);
461 int contains_ecryptfs_marker(char *data
);
462 int ecryptfs_read_header_region(char *data
, struct dentry
*dentry
,
463 struct vfsmount
*mnt
);
464 u16
ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat
*crypt_stat
);
465 int ecryptfs_cipher_code_to_string(char *str
, u16 cipher_code
);
466 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat
*crypt_stat
);
467 int ecryptfs_generate_key_packet_set(char *dest_base
,
468 struct ecryptfs_crypt_stat
*crypt_stat
,
469 struct dentry
*ecryptfs_dentry
,
470 size_t *len
, size_t max
);
471 int process_request_key_err(long err_code
);
473 ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat
*crypt_stat
,
474 unsigned char *src
, struct dentry
*ecryptfs_dentry
);
475 int ecryptfs_truncate(struct dentry
*dentry
, loff_t new_length
);
477 ecryptfs_process_cipher(struct crypto_blkcipher
**key_tfm
, char *cipher_name
,
479 int ecryptfs_inode_test(struct inode
*inode
, void *candidate_lower_inode
);
480 int ecryptfs_inode_set(struct inode
*inode
, void *lower_inode
);
481 void ecryptfs_init_inode(struct inode
*inode
, struct inode
*lower_inode
);
482 int ecryptfs_open_lower_file(struct file
**lower_file
,
483 struct dentry
*lower_dentry
,
484 struct vfsmount
*lower_mnt
, int flags
);
485 int ecryptfs_close_lower_file(struct file
*lower_file
);
487 #endif /* #ifndef ECRYPTFS_KERNEL_H */