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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 */
88struct 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
100struct 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
115enum ecryptfs_token_types {ECRYPTFS_PASSWORD, ECRYPTFS_PRIVATE_KEY};
116
117/* May be a password or a private key */
118struct 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
130void ecryptfs_dump_auth_tok(struct ecryptfs_auth_tok *auth_tok);
131extern void ecryptfs_to_hex(char *dst, char *src, size_t src_size);
132extern void ecryptfs_from_hex(char *dst, char *src, int dst_size);
133
134struct 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
141struct ecryptfs_auth_tok_list {
142 struct ecryptfs_auth_tok *auth_tok;
143 struct list_head list;
144};
145
146struct ecryptfs_crypt_stat;
147struct ecryptfs_mount_crypt_stat;
148
149struct 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
160static inline struct ecryptfs_auth_tok *
161ecryptfs_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 */
190struct 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. */
223struct 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. */
231struct 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 */
242struct 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. */
257struct ecryptfs_sb_info {
258 struct super_block *wsi_sb;
259 struct ecryptfs_mount_crypt_stat mount_crypt_stat;
260};
261
262/* file private data. */
263struct ecryptfs_file_info {
264 struct file *wfi_file;
265 struct ecryptfs_crypt_stat *crypt_stat;
266};
267
268/* auth_tok <=> encrypted_session_key mappings */
269struct 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
275static inline struct ecryptfs_file_info *
276ecryptfs_file_to_private(struct file *file)
277{
278 return (struct ecryptfs_file_info *)file->private_data;
279}
280
281static inline void
282ecryptfs_set_file_private(struct file *file,
283 struct ecryptfs_file_info *file_info)
284{
285 file->private_data = file_info;
286}
287
288static inline struct file *ecryptfs_file_to_lower(struct file *file)
289{
290 return ((struct ecryptfs_file_info *)file->private_data)->wfi_file;
291}
292
293static inline void
294ecryptfs_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
300static inline struct ecryptfs_inode_info *
301ecryptfs_inode_to_private(struct inode *inode)
302{
303 return container_of(inode, struct ecryptfs_inode_info, vfs_inode);
304}
305
306static inline struct inode *ecryptfs_inode_to_lower(struct inode *inode)
307{
308 return ecryptfs_inode_to_private(inode)->wii_inode;
309}
310
311static inline void
312ecryptfs_set_inode_lower(struct inode *inode, struct inode *lower_inode)
313{
314 ecryptfs_inode_to_private(inode)->wii_inode = lower_inode;
315}
316
317static inline struct ecryptfs_sb_info *
318ecryptfs_superblock_to_private(struct super_block *sb)
319{
320 return (struct ecryptfs_sb_info *)sb->s_fs_info;
321}
322
323static inline void
324ecryptfs_set_superblock_private(struct super_block *sb,
325 struct ecryptfs_sb_info *sb_info)
326{
327 sb->s_fs_info = sb_info;
328}
329
330static inline struct super_block *
331ecryptfs_superblock_to_lower(struct super_block *sb)
332{
333 return ((struct ecryptfs_sb_info *)sb->s_fs_info)->wsi_sb;
334}
335
336static inline void
337ecryptfs_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
343static inline struct ecryptfs_dentry_info *
344ecryptfs_dentry_to_private(struct dentry *dentry)
345{
346 return (struct ecryptfs_dentry_info *)dentry->d_fsdata;
347}
348
349static inline void
350ecryptfs_set_dentry_private(struct dentry *dentry,
351 struct ecryptfs_dentry_info *dentry_info)
352{
353 dentry->d_fsdata = dentry_info;
354}
355
356static inline struct dentry *
357ecryptfs_dentry_to_lower(struct dentry *dentry)
358{
359 return ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.dentry;
360}
361
362static inline void
363ecryptfs_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
369static inline struct vfsmount *
370ecryptfs_dentry_to_lower_mnt(struct dentry *dentry)
371{
372 return ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.mnt;
373}
374
375static inline void
376ecryptfs_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);
384void __ecryptfs_printk(const char *fmt, ...);
385
386extern const struct file_operations ecryptfs_main_fops;
387extern const struct file_operations ecryptfs_dir_fops;
388extern struct inode_operations ecryptfs_main_iops;
389extern struct inode_operations ecryptfs_dir_iops;
390extern struct inode_operations ecryptfs_symlink_iops;
391extern struct super_operations ecryptfs_sops;
392extern struct dentry_operations ecryptfs_dops;
393extern struct address_space_operations ecryptfs_aops;
394extern int ecryptfs_verbosity;
395
396extern struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
397extern struct kmem_cache *ecryptfs_file_info_cache;
398extern struct kmem_cache *ecryptfs_dentry_info_cache;
399extern struct kmem_cache *ecryptfs_inode_info_cache;
400extern struct kmem_cache *ecryptfs_sb_info_cache;
401extern struct kmem_cache *ecryptfs_header_cache_0;
402extern struct kmem_cache *ecryptfs_header_cache_1;
403extern struct kmem_cache *ecryptfs_header_cache_2;
404extern struct kmem_cache *ecryptfs_lower_page_cache;
405
406int ecryptfs_interpose(struct dentry *hidden_dentry,
407 struct dentry *this_dentry, struct super_block *sb,
408 int flag);
409int ecryptfs_fill_zeros(struct file *file, loff_t new_length);
410int ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat,
411 const char *name, int length,
412 char **decrypted_name);
413int ecryptfs_encode_filename(struct ecryptfs_crypt_stat *crypt_stat,
414 const char *name, int length,
415 char **encoded_name);
416struct dentry *ecryptfs_lower_dentry(struct dentry *this_dentry);
417void ecryptfs_dump_hex(char *data, int bytes);
418int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
419 int sg_size);
420int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat);
421void ecryptfs_rotate_iv(unsigned char *iv);
422void ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat);
423void ecryptfs_destruct_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat);
424void ecryptfs_destruct_mount_crypt_stat(
425 struct ecryptfs_mount_crypt_stat *mount_crypt_stat);
426int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat);
427int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
428 char *cipher_name,
429 char *chaining_modifier);
430int ecryptfs_write_inode_size_to_header(struct file *lower_file,
431 struct inode *lower_inode,
432 struct inode *inode);
433int 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);
437int
438ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode,
439 struct file *lower_file, int byte_offset,
440 int region_size);
441int ecryptfs_copy_page_to_lower(struct page *page, struct inode *lower_inode,
442 struct file *lower_file);
443int ecryptfs_do_readpage(struct file *file, struct page *page,
444 pgoff_t lower_page_index);
445int 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);
449int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
450 struct inode *lower_inode,
451 struct writeback_control *wbc);
452int ecryptfs_encrypt_page(struct ecryptfs_page_crypt_context *ctx);
453int ecryptfs_decrypt_page(struct file *file, struct page *page);
454int ecryptfs_write_headers(struct dentry *ecryptfs_dentry,
455 struct file *lower_file);
456int ecryptfs_write_headers_virt(char *page_virt,
457 struct ecryptfs_crypt_stat *crypt_stat,
458 struct dentry *ecryptfs_dentry);
459int ecryptfs_read_headers(struct dentry *ecryptfs_dentry,
460 struct file *lower_file);
461int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry);
462int contains_ecryptfs_marker(char *data);
463int ecryptfs_read_header_region(char *data, struct dentry *dentry,
464 struct vfsmount *mnt);
465u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat);
466int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code);
467void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat);
468int 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);
472int process_request_key_err(long err_code);
473int
474ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
475 unsigned char *src, struct dentry *ecryptfs_dentry);
476int ecryptfs_truncate(struct dentry *dentry, loff_t new_length);
477int
478ecryptfs_process_cipher(struct crypto_blkcipher **key_tfm, char *cipher_name,
479 size_t *key_size);
480int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode);
481int ecryptfs_inode_set(struct inode *inode, void *lower_inode);
482void ecryptfs_init_inode(struct inode *inode, struct inode *lower_inode);
483int ecryptfs_open_lower_file(struct file **lower_file,
484 struct dentry *lower_dentry,
485 struct vfsmount *lower_mnt, int flags);
486int ecryptfs_close_lower_file(struct file *lower_file);
487
488#endif /* #ifndef ECRYPTFS_KERNEL_H */