aboutsummaryrefslogtreecommitdiff
path: root/fs/ecryptfs/ecryptfs_kernel.h
blob: 0f897109759baa627ed07c087658e0185672de29 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
/**
 * eCryptfs: Linux filesystem encryption layer
 * Kernel declarations.
 *
 * Copyright (C) 1997-2003 Erez Zadok
 * Copyright (C) 2001-2003 Stony Brook University
 * Copyright (C) 2004-2006 International Business Machines Corp.
 *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 */

#ifndef ECRYPTFS_KERNEL_H
#define ECRYPTFS_KERNEL_H

#include <keys/user-type.h>
#include <linux/fs.h>
#include <linux/fs_stack.h>
#include <linux/namei.h>
#include <linux/scatterlist.h>

/* Version verification for shared data structures w/ userspace */
#define ECRYPTFS_VERSION_MAJOR 0x00
#define ECRYPTFS_VERSION_MINOR 0x04
#define ECRYPTFS_SUPPORTED_FILE_VERSION 0x01
/* These flags indicate which features are supported by the kernel
 * module; userspace tools such as the mount helper read
 * ECRYPTFS_VERSIONING_MASK from a sysfs handle in order to determine
 * how to behave. */
#define ECRYPTFS_VERSIONING_PASSPHRASE 0x00000001
#define ECRYPTFS_VERSIONING_PUBKEY 0x00000002
#define ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH 0x00000004
#define ECRYPTFS_VERSIONING_POLICY 0x00000008
#define ECRYPTFS_VERSIONING_MASK (ECRYPTFS_VERSIONING_PASSPHRASE \
                                  | ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH)

#define ECRYPTFS_MAX_PASSWORD_LENGTH 64
#define ECRYPTFS_MAX_PASSPHRASE_BYTES ECRYPTFS_MAX_PASSWORD_LENGTH
#define ECRYPTFS_SALT_SIZE 8
#define ECRYPTFS_SALT_SIZE_HEX (ECRYPTFS_SALT_SIZE*2)
/* The original signature size is only for what is stored on disk; all
 * in-memory representations are expanded hex, so it better adapted to
 * be passed around or referenced on the command line */
#define ECRYPTFS_SIG_SIZE 8
#define ECRYPTFS_SIG_SIZE_HEX (ECRYPTFS_SIG_SIZE*2)
#define ECRYPTFS_PASSWORD_SIG_SIZE ECRYPTFS_SIG_SIZE_HEX
#define ECRYPTFS_MAX_KEY_BYTES 64
#define ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES 512
#define ECRYPTFS_DEFAULT_IV_BYTES 16
#define ECRYPTFS_FILE_VERSION 0x01
#define ECRYPTFS_DEFAULT_HEADER_EXTENT_SIZE 8192
#define ECRYPTFS_DEFAULT_EXTENT_SIZE 4096
#define ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE 8192

#define RFC2440_CIPHER_DES3_EDE 0x02
#define RFC2440_CIPHER_CAST_5 0x03
#define RFC2440_CIPHER_BLOWFISH 0x04
#define RFC2440_CIPHER_AES_128 0x07
#define RFC2440_CIPHER_AES_192 0x08
#define RFC2440_CIPHER_AES_256 0x09
#define RFC2440_CIPHER_TWOFISH 0x0a
#define RFC2440_CIPHER_CAST_6 0x0b

#define ECRYPTFS_SET_FLAG(flag_bit_vector, flag) (flag_bit_vector |= (flag))
#define ECRYPTFS_CLEAR_FLAG(flag_bit_vector, flag) (flag_bit_vector &= ~(flag))
#define ECRYPTFS_CHECK_FLAG(flag_bit_vector, flag) (flag_bit_vector & (flag))

/**
 * For convenience, we may need to pass around the encrypted session
 * key between kernel and userspace because the authentication token
 * may not be extractable.  For example, the TPM may not release the
 * private key, instead requiring the encrypted data and returning the
 * decrypted data.
 */
struct ecryptfs_session_key {
#define ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT 0x00000001
#define ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT 0x00000002
#define ECRYPTFS_CONTAINS_DECRYPTED_KEY 0x00000004
#define ECRYPTFS_CONTAINS_ENCRYPTED_KEY 0x00000008
	u32 flags;
	u32 encrypted_key_size;
	u32 decrypted_key_size;
	u8 encrypted_key[ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES];
	u8 decrypted_key[ECRYPTFS_MAX_KEY_BYTES];
};

struct ecryptfs_password {
	u32 password_bytes;
	s32 hash_algo;
	u32 hash_iterations;
	u32 session_key_encryption_key_bytes;
#define ECRYPTFS_PERSISTENT_PASSWORD 0x01
#define ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET 0x02
	u32 flags;
	/* Iterated-hash concatenation of salt and passphrase */
	u8 session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
	u8 signature[ECRYPTFS_PASSWORD_SIG_SIZE + 1];
	/* Always in expanded hex */
	u8 salt[ECRYPTFS_SALT_SIZE];
};

enum ecryptfs_token_types {ECRYPTFS_PASSWORD, ECRYPTFS_PRIVATE_KEY};

/* May be a password or a private key */
struct ecryptfs_auth_tok {
	u16 version; /* 8-bit major and 8-bit minor */
	u16 token_type;
	u32 flags;
	struct ecryptfs_session_key session_key;
	u8 reserved[32];
	union {
		struct ecryptfs_password password;
		/* Private key is in future eCryptfs releases */
	} token;
} __attribute__ ((packed));

void ecryptfs_dump_auth_tok(struct ecryptfs_auth_tok *auth_tok);
extern void ecryptfs_to_hex(char *dst, char *src, size_t src_size);
extern void ecryptfs_from_hex(char *dst, char *src, int dst_size);

struct ecryptfs_key_record {
	unsigned char type;
	size_t enc_key_size;
	unsigned char sig[ECRYPTFS_SIG_SIZE];
	unsigned char enc_key[ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES];
};

struct ecryptfs_auth_tok_list {
	struct ecryptfs_auth_tok *auth_tok;
	struct list_head list;
};

struct ecryptfs_crypt_stat;
struct ecryptfs_mount_crypt_stat;

struct ecryptfs_page_crypt_context {
	struct page *page;
#define ECRYPTFS_PREPARE_COMMIT_MODE 0
#define ECRYPTFS_WRITEPAGE_MODE      1
	unsigned int mode;
	union {
		struct file *lower_file;
		struct writeback_control *wbc;
	} param;
};

static inline struct ecryptfs_auth_tok *
ecryptfs_get_key_payload_data(struct key *key)
{
	return (struct ecryptfs_auth_tok *)
		(((struct user_key_payload*)key->payload.data)->data);
}

#define ECRYPTFS_SUPER_MAGIC 0xf15f
#define ECRYPTFS_MAX_KEYSET_SIZE 1024
#define ECRYPTFS_MAX_CIPHER_NAME_SIZE 32
#define ECRYPTFS_MAX_NUM_ENC_KEYS 64
#define ECRYPTFS_MAX_NUM_KEYSIGS 2 /* TODO: Make this a linked list */
#define ECRYPTFS_MAX_IV_BYTES 16	/* 128 bits */
#define ECRYPTFS_SALT_BYTES 2
#define MAGIC_ECRYPTFS_MARKER 0x3c81b7f5
#define MAGIC_ECRYPTFS_MARKER_SIZE_BYTES 8	/* 4*2 */
#define ECRYPTFS_FILE_SIZE_BYTES 8
#define ECRYPTFS_DEFAULT_CIPHER "aes"
#define ECRYPTFS_DEFAULT_KEY_BYTES 16
#define ECRYPTFS_DEFAULT_HASH "md5"
#define ECRYPTFS_TAG_3_PACKET_TYPE 0x8C
#define ECRYPTFS_TAG_11_PACKET_TYPE 0xED
#define MD5_DIGEST_SIZE 16

/**
 * This is the primary struct associated with each encrypted file.
 *
 * TODO: cache align/pack?
 */
struct ecryptfs_crypt_stat {
#define ECRYPTFS_STRUCT_INITIALIZED 0x00000001
#define ECRYPTFS_POLICY_APPLIED     0x00000002
#define ECRYPTFS_NEW_FILE           0x00000004
#define ECRYPTFS_ENCRYPTED          0x00000008
#define ECRYPTFS_SECURITY_WARNING   0x00000010
#define ECRYPTFS_ENABLE_HMAC        0x00000020
#define ECRYPTFS_ENCRYPT_IV_PAGES   0x00000040
#define ECRYPTFS_KEY_VALID          0x00000080
	u32 flags;
	unsigned int file_version;
	size_t iv_bytes;
	size_t num_keysigs;
	size_t header_extent_size;
	size_t num_header_extents_at_front;
	size_t extent_size; /* Data extent size; default is 4096 */
	size_t key_size;
	size_t extent_shift;
	unsigned int extent_mask;
	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
	struct crypto_blkcipher *tfm;
	struct crypto_hash *hash_tfm; /* Crypto context for generating
				       * the initialization vectors */
	unsigned char cipher[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
	unsigned char key[ECRYPTFS_MAX_KEY_BYTES];
	unsigned char root_iv[ECRYPTFS_MAX_IV_BYTES];
	unsigned char keysigs[ECRYPTFS_MAX_NUM_KEYSIGS][ECRYPTFS_SIG_SIZE_HEX];
	struct mutex cs_tfm_mutex;
	struct mutex cs_hash_tfm_mutex;
	struct mutex cs_mutex;
};

/* inode private data. */
struct ecryptfs_inode_info {
	struct inode vfs_inode;
	struct inode *wii_inode;
	struct ecryptfs_crypt_stat crypt_stat;
};

/* dentry private data. Each dentry must keep track of a lower
 * vfsmount too. */
struct ecryptfs_dentry_info {
	struct path lower_path;
	struct ecryptfs_crypt_stat *crypt_stat;
};

/**
 * This struct is to enable a mount-wide passphrase/salt combo. This
 * is more or less a stopgap to provide similar functionality to other
 * crypto filesystems like EncFS or CFS until full policy support is
 * implemented in eCryptfs.
 */
struct ecryptfs_mount_crypt_stat {
	/* Pointers to memory we do not own, do not free these */
#define ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED 0x00000001
	u32 flags;
	struct ecryptfs_auth_tok *global_auth_tok;
	struct key *global_auth_tok_key;
	size_t global_default_cipher_key_size;
	struct crypto_blkcipher *global_key_tfm;
	struct mutex global_key_tfm_mutex;
	unsigned char global_default_cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE
						 + 1];
	unsigned char global_auth_tok_sig[ECRYPTFS_SIG_SIZE_HEX + 1];
};

/* superblock private data. */
struct ecryptfs_sb_info {
	struct super_block *wsi_sb;
	struct ecryptfs_mount_crypt_stat mount_crypt_stat;
};

/* file private data. */
struct ecryptfs_file_info {
	struct file *wfi_file;
	struct ecryptfs_crypt_stat *crypt_stat;
};

/* auth_tok <=> encrypted_session_key mappings */
struct ecryptfs_auth_tok_list_item {
	unsigned char encrypted_session_key[ECRYPTFS_MAX_KEY_BYTES];
	struct list_head list;
	struct ecryptfs_auth_tok auth_tok;
};

static inline struct ecryptfs_file_info *
ecryptfs_file_to_private(struct file *file)
{
	return (struct ecryptfs_file_info *)file->private_data;
}

static inline void
ecryptfs_set_file_private(struct file *file,
			  struct ecryptfs_file_info *file_info)
{
	file->private_data = file_info;
}

static inline struct file *ecryptfs_file_to_lower(struct file *file)
{
	return ((struct ecryptfs_file_info *)file->private_data)->wfi_file;
}

static inline void
ecryptfs_set_file_lower(struct file *file, struct file *lower_file)
{
	((struct ecryptfs_file_info *)file->private_data)->wfi_file =
		lower_file;
}

static inline struct ecryptfs_inode_info *
ecryptfs_inode_to_private(struct inode *inode)
{
	return container_of(inode, struct ecryptfs_inode_info, vfs_inode);
}

static inline struct inode *ecryptfs_inode_to_lower(struct inode *inode)
{
	return ecryptfs_inode_to_private(inode)->wii_inode;
}

static inline void
ecryptfs_set_inode_lower(struct inode *inode, struct inode *lower_inode)
{
	ecryptfs_inode_to_private(inode)->wii_inode = lower_inode;
}

static inline struct ecryptfs_sb_info *
ecryptfs_superblock_to_private(struct super_block *sb)
{
	return (struct ecryptfs_sb_info *)sb->s_fs_info;
}

static inline void
ecryptfs_set_superblock_private(struct super_block *sb,
				struct ecryptfs_sb_info *sb_info)
{
	sb->s_fs_info = sb_info;
}

static inline struct super_block *
ecryptfs_superblock_to_lower(struct super_block *sb)
{
	return ((struct ecryptfs_sb_info *)sb->s_fs_info)->wsi_sb;
}

static inline void
ecryptfs_set_superblock_lower(struct super_block *sb,
			      struct super_block *lower_sb)
{
	((struct ecryptfs_sb_info *)sb->s_fs_info)->wsi_sb = lower_sb;
}

static inline struct ecryptfs_dentry_info *
ecryptfs_dentry_to_private(struct dentry *dentry)
{
	return (struct ecryptfs_dentry_info *)dentry->d_fsdata;
}

static inline void
ecryptfs_set_dentry_private(struct dentry *dentry,
			    struct ecryptfs_dentry_info *dentry_info)
{
	dentry->d_fsdata = dentry_info;
}

static inline struct dentry *
ecryptfs_dentry_to_lower(struct dentry *dentry)
{
	return ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.dentry;
}

static inline void
ecryptfs_set_dentry_lower(struct dentry *dentry, struct dentry *lower_dentry)
{
	((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.dentry =
		lower_dentry;
}

static inline struct vfsmount *
ecryptfs_dentry_to_lower_mnt(struct dentry *dentry)
{
	return ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.mnt;
}

static inline void
ecryptfs_set_dentry_lower_mnt(struct dentry *dentry, struct vfsmount *lower_mnt)
{
	((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.mnt =
		lower_mnt;
}

#define ecryptfs_printk(type, fmt, arg...) \
        __ecryptfs_printk(type "%s: " fmt, __FUNCTION__, ## arg);
void __ecryptfs_printk(const char *fmt, ...);

extern const struct file_operations ecryptfs_main_fops;
extern const struct file_operations ecryptfs_dir_fops;
extern struct inode_operations ecryptfs_main_iops;
extern struct inode_operations ecryptfs_dir_iops;
extern struct inode_operations ecryptfs_symlink_iops;
extern struct super_operations ecryptfs_sops;
extern struct dentry_operations ecryptfs_dops;
extern struct address_space_operations ecryptfs_aops;
extern int ecryptfs_verbosity;

extern struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
extern struct kmem_cache *ecryptfs_file_info_cache;
extern struct kmem_cache *ecryptfs_dentry_info_cache;
extern struct kmem_cache *ecryptfs_inode_info_cache;
extern struct kmem_cache *ecryptfs_sb_info_cache;
extern struct kmem_cache *ecryptfs_header_cache_0;
extern struct kmem_cache *ecryptfs_header_cache_1;
extern struct kmem_cache *ecryptfs_header_cache_2;
extern struct kmem_cache *ecryptfs_lower_page_cache;

int ecryptfs_interpose(struct dentry *hidden_dentry,
		       struct dentry *this_dentry, struct super_block *sb,
		       int flag);
int ecryptfs_fill_zeros(struct file *file, loff_t new_length);
int ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat,
			     const char *name, int length,
			     char **decrypted_name);
int ecryptfs_encode_filename(struct ecryptfs_crypt_stat *crypt_stat,
			     const char *name, int length,
			     char **encoded_name);
struct dentry *ecryptfs_lower_dentry(struct dentry *this_dentry);
void ecryptfs_dump_hex(char *data, int bytes);
int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
			int sg_size);
int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat);
void ecryptfs_rotate_iv(unsigned char *iv);
void ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat);
void ecryptfs_destruct_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat);
void ecryptfs_destruct_mount_crypt_stat(
	struct ecryptfs_mount_crypt_stat *mount_crypt_stat);
int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat);
int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
					   char *cipher_name,
					   char *chaining_modifier);
int ecryptfs_write_inode_size_to_header(struct file *lower_file,
					struct inode *lower_inode,
					struct inode *inode);
int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode,
			    struct file *lower_file,
			    unsigned long lower_page_index, int byte_offset,
			    int region_bytes);
int
ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode,
			   struct file *lower_file, int byte_offset,
			   int region_size);
int ecryptfs_copy_page_to_lower(struct page *page, struct inode *lower_inode,
				struct file *lower_file);
int ecryptfs_do_readpage(struct file *file, struct page *page,
			 pgoff_t lower_page_index);
int ecryptfs_grab_and_map_lower_page(struct page **lower_page,
				     char **lower_virt,
				     struct inode *lower_inode,
				     unsigned long lower_page_index);
int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
					      struct inode *lower_inode,
					      struct writeback_control *wbc);
int ecryptfs_encrypt_page(struct ecryptfs_page_crypt_context *ctx);
int ecryptfs_decrypt_page(struct file *file, struct page *page);
int ecryptfs_write_headers(struct dentry *ecryptfs_dentry,
			   struct file *lower_file);
int ecryptfs_write_headers_virt(char *page_virt,
				struct ecryptfs_crypt_stat *crypt_stat,
				struct dentry *ecryptfs_dentry);
int ecryptfs_read_headers(struct dentry *ecryptfs_dentry,
			  struct file *lower_file);
int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry);
int contains_ecryptfs_marker(char *data);
int ecryptfs_read_header_region(char *data, struct dentry *dentry,
				struct vfsmount *mnt);
u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat);
int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code);
void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat);
int ecryptfs_generate_key_packet_set(char *dest_base,
				     struct ecryptfs_crypt_stat *crypt_stat,
				     struct dentry *ecryptfs_dentry,
				     size_t *len, size_t max);
int process_request_key_err(long err_code);
int
ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
			  unsigned char *src, struct dentry *ecryptfs_dentry);
int ecryptfs_truncate(struct dentry *dentry, loff_t new_length);
int
ecryptfs_process_cipher(struct crypto_blkcipher **key_tfm, char *cipher_name,
			size_t *key_size);
int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode);
int ecryptfs_inode_set(struct inode *inode, void *lower_inode);
void ecryptfs_init_inode(struct inode *inode, struct inode *lower_inode);
int ecryptfs_open_lower_file(struct file **lower_file,
			     struct dentry *lower_dentry,
			     struct vfsmount *lower_mnt, int flags);
int ecryptfs_close_lower_file(struct file *lower_file);

#endif /* #ifndef ECRYPTFS_KERNEL_H */