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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/scatterlist.h>
32
33/* Version verification for shared data structures w/ userspace */
34#define ECRYPTFS_VERSION_MAJOR 0x00
35#define ECRYPTFS_VERSION_MINOR 0x04
36#define ECRYPTFS_SUPPORTED_FILE_VERSION 0x01
37/* These flags indicate which features are supported by the kernel
38 * module; userspace tools such as the mount helper read
39 * ECRYPTFS_VERSIONING_MASK from a sysfs handle in order to determine
40 * how to behave. */
41#define ECRYPTFS_VERSIONING_PASSPHRASE 0x00000001
42#define ECRYPTFS_VERSIONING_PUBKEY 0x00000002
43#define ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH 0x00000004
44#define ECRYPTFS_VERSIONING_POLICY 0x00000008
45#define ECRYPTFS_VERSIONING_MASK (ECRYPTFS_VERSIONING_PASSPHRASE \
46 | ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH)
47
48#define ECRYPTFS_MAX_PASSWORD_LENGTH 64
49#define ECRYPTFS_MAX_PASSPHRASE_BYTES ECRYPTFS_MAX_PASSWORD_LENGTH
50#define ECRYPTFS_SALT_SIZE 8
51#define ECRYPTFS_SALT_SIZE_HEX (ECRYPTFS_SALT_SIZE*2)
52/* The original signature size is only for what is stored on disk; all
53 * in-memory representations are expanded hex, so it better adapted to
54 * be passed around or referenced on the command line */
55#define ECRYPTFS_SIG_SIZE 8
56#define ECRYPTFS_SIG_SIZE_HEX (ECRYPTFS_SIG_SIZE*2)
57#define ECRYPTFS_PASSWORD_SIG_SIZE ECRYPTFS_SIG_SIZE_HEX
58#define ECRYPTFS_MAX_KEY_BYTES 64
59#define ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES 512
60#define ECRYPTFS_DEFAULT_IV_BYTES 16
61#define ECRYPTFS_FILE_VERSION 0x01
62#define ECRYPTFS_DEFAULT_HEADER_EXTENT_SIZE 8192
63#define ECRYPTFS_DEFAULT_EXTENT_SIZE 4096
64#define ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE 8192
65
66#define RFC2440_CIPHER_DES3_EDE 0x02
67#define RFC2440_CIPHER_CAST_5 0x03
68#define RFC2440_CIPHER_BLOWFISH 0x04
69#define RFC2440_CIPHER_AES_128 0x07
70#define RFC2440_CIPHER_AES_192 0x08
71#define RFC2440_CIPHER_AES_256 0x09
72#define RFC2440_CIPHER_TWOFISH 0x0a
73#define RFC2440_CIPHER_CAST_6 0x0b
74
75#define ECRYPTFS_SET_FLAG(flag_bit_vector, flag) (flag_bit_vector |= (flag))
76#define ECRYPTFS_CLEAR_FLAG(flag_bit_vector, flag) (flag_bit_vector &= ~(flag))
77#define ECRYPTFS_CHECK_FLAG(flag_bit_vector, flag) (flag_bit_vector & (flag))
78
79/**
80 * For convenience, we may need to pass around the encrypted session
81 * key between kernel and userspace because the authentication token
82 * may not be extractable. For example, the TPM may not release the
83 * private key, instead requiring the encrypted data and returning the
84 * decrypted data.
85 */
86struct ecryptfs_session_key {
87#define ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT 0x00000001
88#define ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT 0x00000002
89#define ECRYPTFS_CONTAINS_DECRYPTED_KEY 0x00000004
90#define ECRYPTFS_CONTAINS_ENCRYPTED_KEY 0x00000008
91 u32 flags;
92 u32 encrypted_key_size;
93 u32 decrypted_key_size;
94 u8 encrypted_key[ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES];
95 u8 decrypted_key[ECRYPTFS_MAX_KEY_BYTES];
96};
97
98struct ecryptfs_password {
99 u32 password_bytes;
100 s32 hash_algo;
101 u32 hash_iterations;
102 u32 session_key_encryption_key_bytes;
103#define ECRYPTFS_PERSISTENT_PASSWORD 0x01
104#define ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET 0x02
105 u32 flags;
106 /* Iterated-hash concatenation of salt and passphrase */
107 u8 session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
108 u8 signature[ECRYPTFS_PASSWORD_SIG_SIZE + 1];
109 /* Always in expanded hex */
110 u8 salt[ECRYPTFS_SALT_SIZE];
111};
112
113enum ecryptfs_token_types {ECRYPTFS_PASSWORD, ECRYPTFS_PRIVATE_KEY};
114
115/* May be a password or a private key */
116struct ecryptfs_auth_tok {
117 u16 version; /* 8-bit major and 8-bit minor */
118 u16 token_type;
119 u32 flags;
120 struct ecryptfs_session_key session_key;
121 u8 reserved[32];
122 union {
123 struct ecryptfs_password password;
124 /* Private key is in future eCryptfs releases */
125 } token;
126} __attribute__ ((packed));
127
128void ecryptfs_dump_auth_tok(struct ecryptfs_auth_tok *auth_tok);
129extern void ecryptfs_to_hex(char *dst, char *src, size_t src_size);
130extern void ecryptfs_from_hex(char *dst, char *src, int dst_size);
131
132struct ecryptfs_key_record {
133 unsigned char type;
134 size_t enc_key_size;
135 unsigned char sig[ECRYPTFS_SIG_SIZE];
136 unsigned char enc_key[ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES];
137};
138
139struct ecryptfs_auth_tok_list {
140 struct ecryptfs_auth_tok *auth_tok;
141 struct list_head list;
142};
143
144struct ecryptfs_crypt_stat;
145struct ecryptfs_mount_crypt_stat;
146
147struct ecryptfs_page_crypt_context {
148 struct page *page;
149#define ECRYPTFS_PREPARE_COMMIT_MODE 0
150#define ECRYPTFS_WRITEPAGE_MODE 1
151 unsigned int mode;
152 union {
153 struct file *lower_file;
154 struct writeback_control *wbc;
155 } param;
156};
157
158static inline struct ecryptfs_auth_tok *
159ecryptfs_get_key_payload_data(struct key *key)
160{
161 return (struct ecryptfs_auth_tok *)
162 (((struct user_key_payload*)key->payload.data)->data);
163}
164
165#define ECRYPTFS_SUPER_MAGIC 0xf15f
166#define ECRYPTFS_MAX_KEYSET_SIZE 1024
167#define ECRYPTFS_MAX_CIPHER_NAME_SIZE 32
168#define ECRYPTFS_MAX_NUM_ENC_KEYS 64
169#define ECRYPTFS_MAX_NUM_KEYSIGS 2 /* TODO: Make this a linked list */
170#define ECRYPTFS_MAX_IV_BYTES 16 /* 128 bits */
171#define ECRYPTFS_SALT_BYTES 2
172#define MAGIC_ECRYPTFS_MARKER 0x3c81b7f5
173#define MAGIC_ECRYPTFS_MARKER_SIZE_BYTES 8 /* 4*2 */
174#define ECRYPTFS_FILE_SIZE_BYTES 8
175#define ECRYPTFS_DEFAULT_CIPHER "aes"
176#define ECRYPTFS_DEFAULT_KEY_BYTES 16
177#define ECRYPTFS_DEFAULT_CHAINING_MODE CRYPTO_TFM_MODE_CBC
178#define ECRYPTFS_TAG_3_PACKET_TYPE 0x8C
179#define ECRYPTFS_TAG_11_PACKET_TYPE 0xED
180#define MD5_DIGEST_SIZE 16
181
182/**
183 * This is the primary struct associated with each encrypted file.
184 *
185 * TODO: cache align/pack?
186 */
187struct ecryptfs_crypt_stat {
188#define ECRYPTFS_STRUCT_INITIALIZED 0x00000001
189#define ECRYPTFS_POLICY_APPLIED 0x00000002
190#define ECRYPTFS_NEW_FILE 0x00000004
191#define ECRYPTFS_ENCRYPTED 0x00000008
192#define ECRYPTFS_SECURITY_WARNING 0x00000010
193#define ECRYPTFS_ENABLE_HMAC 0x00000020
194#define ECRYPTFS_ENCRYPT_IV_PAGES 0x00000040
195#define ECRYPTFS_KEY_VALID 0x00000080
196 u32 flags;
197 unsigned int file_version;
198 size_t iv_bytes;
199 size_t num_keysigs;
200 size_t header_extent_size;
201 size_t num_header_extents_at_front;
202 size_t extent_size; /* Data extent size; default is 4096 */
203 size_t key_size;
204 size_t extent_shift;
205 unsigned int extent_mask;
206 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
207 struct crypto_tfm *tfm;
208 struct crypto_tfm *md5_tfm; /* Crypto context for generating
209 * the initialization vectors */
210 unsigned char cipher[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
211 unsigned char key[ECRYPTFS_MAX_KEY_BYTES];
212 unsigned char root_iv[ECRYPTFS_MAX_IV_BYTES];
213 unsigned char keysigs[ECRYPTFS_MAX_NUM_KEYSIGS][ECRYPTFS_SIG_SIZE_HEX];
214 struct mutex cs_tfm_mutex;
215 struct mutex cs_md5_tfm_mutex;
216 struct mutex cs_mutex;
217};
218
219/* inode private data. */
220struct ecryptfs_inode_info {
221 struct inode vfs_inode;
222 struct inode *wii_inode;
223 struct ecryptfs_crypt_stat crypt_stat;
224};
225
226/* dentry private data. Each dentry must keep track of a lower
227 * vfsmount too. */
228struct ecryptfs_dentry_info {
229 struct dentry *wdi_dentry;
230 struct vfsmount *lower_mnt;
231 struct ecryptfs_crypt_stat *crypt_stat;
232};
233
234/**
235 * This struct is to enable a mount-wide passphrase/salt combo. This
236 * is more or less a stopgap to provide similar functionality to other
237 * crypto filesystems like EncFS or CFS until full policy support is
238 * implemented in eCryptfs.
239 */
240struct ecryptfs_mount_crypt_stat {
241 /* Pointers to memory we do not own, do not free these */
242#define ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED 0x00000001
243 u32 flags;
244 struct ecryptfs_auth_tok *global_auth_tok;
245 struct key *global_auth_tok_key;
246 size_t global_default_cipher_key_size;
247 struct crypto_tfm *global_key_tfm;
248 struct mutex global_key_tfm_mutex;
249 unsigned char global_default_cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE
250 + 1];
251 unsigned char global_auth_tok_sig[ECRYPTFS_SIG_SIZE_HEX + 1];
252};
253
254/* superblock private data. */
255struct ecryptfs_sb_info {
256 struct super_block *wsi_sb;
257 struct ecryptfs_mount_crypt_stat mount_crypt_stat;
258};
259
260/* file private data. */
261struct ecryptfs_file_info {
262 struct file *wfi_file;
263 struct ecryptfs_crypt_stat *crypt_stat;
264};
265
266/* auth_tok <=> encrypted_session_key mappings */
267struct ecryptfs_auth_tok_list_item {
268 unsigned char encrypted_session_key[ECRYPTFS_MAX_KEY_BYTES];
269 struct list_head list;
270 struct ecryptfs_auth_tok auth_tok;
271};
272
273static inline struct ecryptfs_file_info *
274ecryptfs_file_to_private(struct file *file)
275{
276 return (struct ecryptfs_file_info *)file->private_data;
277}
278
279static inline void
280ecryptfs_set_file_private(struct file *file,
281 struct ecryptfs_file_info *file_info)
282{
283 file->private_data = file_info;
284}
285
286static inline struct file *ecryptfs_file_to_lower(struct file *file)
287{
288 return ((struct ecryptfs_file_info *)file->private_data)->wfi_file;
289}
290
291static inline void
292ecryptfs_set_file_lower(struct file *file, struct file *lower_file)
293{
294 ((struct ecryptfs_file_info *)file->private_data)->wfi_file =
295 lower_file;
296}
297
298static inline struct ecryptfs_inode_info *
299ecryptfs_inode_to_private(struct inode *inode)
300{
301 return container_of(inode, struct ecryptfs_inode_info, vfs_inode);
302}
303
304static inline struct inode *ecryptfs_inode_to_lower(struct inode *inode)
305{
306 return ecryptfs_inode_to_private(inode)->wii_inode;
307}
308
309static inline void
310ecryptfs_set_inode_lower(struct inode *inode, struct inode *lower_inode)
311{
312 ecryptfs_inode_to_private(inode)->wii_inode = lower_inode;
313}
314
315static inline struct ecryptfs_sb_info *
316ecryptfs_superblock_to_private(struct super_block *sb)
317{
318 return (struct ecryptfs_sb_info *)sb->s_fs_info;
319}
320
321static inline void
322ecryptfs_set_superblock_private(struct super_block *sb,
323 struct ecryptfs_sb_info *sb_info)
324{
325 sb->s_fs_info = sb_info;
326}
327
328static inline struct super_block *
329ecryptfs_superblock_to_lower(struct super_block *sb)
330{
331 return ((struct ecryptfs_sb_info *)sb->s_fs_info)->wsi_sb;
332}
333
334static inline void
335ecryptfs_set_superblock_lower(struct super_block *sb,
336 struct super_block *lower_sb)
337{
338 ((struct ecryptfs_sb_info *)sb->s_fs_info)->wsi_sb = lower_sb;
339}
340
341static inline struct ecryptfs_dentry_info *
342ecryptfs_dentry_to_private(struct dentry *dentry)
343{
344 return (struct ecryptfs_dentry_info *)dentry->d_fsdata;
345}
346
347static inline void
348ecryptfs_set_dentry_private(struct dentry *dentry,
349 struct ecryptfs_dentry_info *dentry_info)
350{
351 dentry->d_fsdata = dentry_info;
352}
353
354static inline struct dentry *
355ecryptfs_dentry_to_lower(struct dentry *dentry)
356{
357 return ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->wdi_dentry;
358}
359
360static inline void
361ecryptfs_set_dentry_lower(struct dentry *dentry, struct dentry *lower_dentry)
362{
363 ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->wdi_dentry =
364 lower_dentry;
365}
366
367static inline struct vfsmount *
368ecryptfs_dentry_to_lower_mnt(struct dentry *dentry)
369{
370 return ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_mnt;
371}
372
373static inline void
374ecryptfs_set_dentry_lower_mnt(struct dentry *dentry, struct vfsmount *lower_mnt)
375{
376 ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_mnt =
377 lower_mnt;
378}
379
380#define ecryptfs_printk(type, fmt, arg...) \
381 __ecryptfs_printk(type "%s: " fmt, __FUNCTION__, ## arg);
382void __ecryptfs_printk(const char *fmt, ...);
383
384extern const struct file_operations ecryptfs_main_fops;
385extern const struct file_operations ecryptfs_dir_fops;
386extern struct inode_operations ecryptfs_main_iops;
387extern struct inode_operations ecryptfs_dir_iops;
388extern struct inode_operations ecryptfs_symlink_iops;
389extern struct super_operations ecryptfs_sops;
390extern struct dentry_operations ecryptfs_dops;
391extern struct address_space_operations ecryptfs_aops;
392extern int ecryptfs_verbosity;
393
394extern struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
395extern struct kmem_cache *ecryptfs_file_info_cache;
396extern struct kmem_cache *ecryptfs_dentry_info_cache;
397extern struct kmem_cache *ecryptfs_inode_info_cache;
398extern struct kmem_cache *ecryptfs_sb_info_cache;
399extern struct kmem_cache *ecryptfs_header_cache_0;
400extern struct kmem_cache *ecryptfs_header_cache_1;
401extern struct kmem_cache *ecryptfs_header_cache_2;
402extern struct kmem_cache *ecryptfs_lower_page_cache;
403
404int ecryptfs_interpose(struct dentry *hidden_dentry,
405 struct dentry *this_dentry, struct super_block *sb,
406 int flag);
407int ecryptfs_fill_zeros(struct file *file, loff_t new_length);
408int ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat,
409 const char *name, int length,
410 char **decrypted_name);
411int ecryptfs_encode_filename(struct ecryptfs_crypt_stat *crypt_stat,
412 const char *name, int length,
413 char **encoded_name);
414struct dentry *ecryptfs_lower_dentry(struct dentry *this_dentry);
415void ecryptfs_copy_attr_atime(struct inode *dest, const struct inode *src);
416void ecryptfs_copy_attr_all(struct inode *dest, const struct inode *src);
417void ecryptfs_copy_inode_size(struct inode *dst, const struct inode *src);
418void ecryptfs_dump_hex(char *data, int bytes);
419int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
420 int sg_size);
421int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat);
422void ecryptfs_rotate_iv(unsigned char *iv);
423void ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat);
424void ecryptfs_destruct_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat);
425void ecryptfs_destruct_mount_crypt_stat(
426 struct ecryptfs_mount_crypt_stat *mount_crypt_stat);
427int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat);
428int ecryptfs_write_inode_size_to_header(struct file *lower_file,
429 struct inode *lower_inode,
430 struct inode *inode);
431int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode,
432 struct file *lower_file,
433 unsigned long lower_page_index, int byte_offset,
434 int region_bytes);
435int
436ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode,
437 struct file *lower_file, int byte_offset,
438 int region_size);
439int ecryptfs_copy_page_to_lower(struct page *page, struct inode *lower_inode,
440 struct file *lower_file);
441int ecryptfs_do_readpage(struct file *file, struct page *page,
442 pgoff_t lower_page_index);
443int ecryptfs_grab_and_map_lower_page(struct page **lower_page,
444 char **lower_virt,
445 struct inode *lower_inode,
446 unsigned long lower_page_index);
447int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
448 struct inode *lower_inode,
449 struct writeback_control *wbc);
450int ecryptfs_encrypt_page(struct ecryptfs_page_crypt_context *ctx);
451int ecryptfs_decrypt_page(struct file *file, struct page *page);
452int ecryptfs_write_headers(struct dentry *ecryptfs_dentry,
453 struct file *lower_file);
454int ecryptfs_write_headers_virt(char *page_virt,
455 struct ecryptfs_crypt_stat *crypt_stat,
456 struct dentry *ecryptfs_dentry);
457int ecryptfs_read_headers(struct dentry *ecryptfs_dentry,
458 struct file *lower_file);
459int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry);
460int contains_ecryptfs_marker(char *data);
461int ecryptfs_read_header_region(char *data, struct dentry *dentry,
462 struct vfsmount *mnt);
463u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat);
464int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code);
465void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat);
466int ecryptfs_generate_key_packet_set(char *dest_base,
467 struct ecryptfs_crypt_stat *crypt_stat,
468 struct dentry *ecryptfs_dentry,
469 size_t *len, size_t max);
470int process_request_key_err(long err_code);
471int
472ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
473 unsigned char *src, struct dentry *ecryptfs_dentry);
474int ecryptfs_truncate(struct dentry *dentry, loff_t new_length);
475int
476ecryptfs_process_cipher(struct crypto_tfm **tfm, struct crypto_tfm **key_tfm,
477 char *cipher_name, size_t key_size);
478int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode);
479int ecryptfs_inode_set(struct inode *inode, void *lower_inode);
480void ecryptfs_init_inode(struct inode *inode, struct inode *lower_inode);
481
482#endif /* #ifndef ECRYPTFS_KERNEL_H */