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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_HASH "md5"
180 #define ECRYPTFS_TAG_3_PACKET_TYPE 0x8C
181 #define ECRYPTFS_TAG_11_PACKET_TYPE 0xED
182 #define MD5_DIGEST_SIZE 16
183
184 /**
185 * This is the primary struct associated with each encrypted file.
186 *
187 * TODO: cache align/pack?
188 */
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
198 u32 flags;
199 unsigned int file_version;
200 size_t iv_bytes;
201 size_t num_keysigs;
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 */
205 size_t key_size;
206 size_t extent_shift;
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;
219 };
220
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;
226 };
227
228 /* dentry private data. Each dentry must keep track of a lower
229 * vfsmount too. */
230 struct ecryptfs_dentry_info {
231 struct path lower_path;
232 struct ecryptfs_crypt_stat *crypt_stat;
233 };
234
235 /**
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.
240 */
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
244 u32 flags;
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
251 + 1];
252 unsigned char global_auth_tok_sig[ECRYPTFS_SIG_SIZE_HEX + 1];
253 };
254
255 /* superblock private data. */
256 struct ecryptfs_sb_info {
257 struct super_block *wsi_sb;
258 struct ecryptfs_mount_crypt_stat mount_crypt_stat;
259 };
260
261 /* file private data. */
262 struct ecryptfs_file_info {
263 struct file *wfi_file;
264 struct ecryptfs_crypt_stat *crypt_stat;
265 };
266
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;
272 };
273
274 static inline struct ecryptfs_file_info *
275 ecryptfs_file_to_private(struct file *file)
276 {
277 return (struct ecryptfs_file_info *)file->private_data;
278 }
279
280 static inline void
281 ecryptfs_set_file_private(struct file *file,
282 struct ecryptfs_file_info *file_info)
283 {
284 file->private_data = file_info;
285 }
286
287 static inline struct file *ecryptfs_file_to_lower(struct file *file)
288 {
289 return ((struct ecryptfs_file_info *)file->private_data)->wfi_file;
290 }
291
292 static inline void
293 ecryptfs_set_file_lower(struct file *file, struct file *lower_file)
294 {
295 ((struct ecryptfs_file_info *)file->private_data)->wfi_file =
296 lower_file;
297 }
298
299 static inline struct ecryptfs_inode_info *
300 ecryptfs_inode_to_private(struct inode *inode)
301 {
302 return container_of(inode, struct ecryptfs_inode_info, vfs_inode);
303 }
304
305 static inline struct inode *ecryptfs_inode_to_lower(struct inode *inode)
306 {
307 return ecryptfs_inode_to_private(inode)->wii_inode;
308 }
309
310 static inline void
311 ecryptfs_set_inode_lower(struct inode *inode, struct inode *lower_inode)
312 {
313 ecryptfs_inode_to_private(inode)->wii_inode = lower_inode;
314 }
315
316 static inline struct ecryptfs_sb_info *
317 ecryptfs_superblock_to_private(struct super_block *sb)
318 {
319 return (struct ecryptfs_sb_info *)sb->s_fs_info;
320 }
321
322 static inline void
323 ecryptfs_set_superblock_private(struct super_block *sb,
324 struct ecryptfs_sb_info *sb_info)
325 {
326 sb->s_fs_info = sb_info;
327 }
328
329 static inline struct super_block *
330 ecryptfs_superblock_to_lower(struct super_block *sb)
331 {
332 return ((struct ecryptfs_sb_info *)sb->s_fs_info)->wsi_sb;
333 }
334
335 static inline void
336 ecryptfs_set_superblock_lower(struct super_block *sb,
337 struct super_block *lower_sb)
338 {
339 ((struct ecryptfs_sb_info *)sb->s_fs_info)->wsi_sb = lower_sb;
340 }
341
342 static inline struct ecryptfs_dentry_info *
343 ecryptfs_dentry_to_private(struct dentry *dentry)
344 {
345 return (struct ecryptfs_dentry_info *)dentry->d_fsdata;
346 }
347
348 static inline void
349 ecryptfs_set_dentry_private(struct dentry *dentry,
350 struct ecryptfs_dentry_info *dentry_info)
351 {
352 dentry->d_fsdata = dentry_info;
353 }
354
355 static inline struct dentry *
356 ecryptfs_dentry_to_lower(struct dentry *dentry)
357 {
358 return ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.dentry;
359 }
360
361 static inline void
362 ecryptfs_set_dentry_lower(struct dentry *dentry, struct dentry *lower_dentry)
363 {
364 ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.dentry =
365 lower_dentry;
366 }
367
368 static inline struct vfsmount *
369 ecryptfs_dentry_to_lower_mnt(struct dentry *dentry)
370 {
371 return ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.mnt;
372 }
373
374 static inline void
375 ecryptfs_set_dentry_lower_mnt(struct dentry *dentry, struct vfsmount *lower_mnt)
376 {
377 ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.mnt =
378 lower_mnt;
379 }
380
381 #define ecryptfs_printk(type, fmt, arg...) \
382 __ecryptfs_printk(type "%s: " fmt, __FUNCTION__, ## arg);
383 void __ecryptfs_printk(const char *fmt, ...);
384
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;
394
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;
404
405 int ecryptfs_interpose(struct dentry *hidden_dentry,
406 struct dentry *this_dentry, struct super_block *sb,
407 int flag);
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,
418 int sg_size);
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,
427 char *cipher_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,
435 int region_bytes);
436 int
437 ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode,
438 struct file *lower_file, int byte_offset,
439 int region_size);
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,
445 char **lower_virt,
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);
472 int
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);
476 int
477 ecryptfs_process_cipher(struct crypto_blkcipher **key_tfm, char *cipher_name,
478 size_t *key_size);
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);
486
487 #endif /* #ifndef ECRYPTFS_KERNEL_H */