2 * eCryptfs: Linux filesystem encryption layer
4 * Copyright (C) 1997-2004 Erez Zadok
5 * Copyright (C) 2001-2004 Stony Brook University
6 * Copyright (C) 2004-2007 International Business Machines Corp.
7 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
8 * Michael C. Thompson <mcthomps@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
27 #include <linux/mount.h>
28 #include <linux/pagemap.h>
29 #include <linux/random.h>
30 #include <linux/compiler.h>
31 #include <linux/key.h>
32 #include <linux/namei.h>
33 #include <linux/crypto.h>
34 #include <linux/file.h>
35 #include <linux/scatterlist.h>
36 #include "ecryptfs_kernel.h"
39 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat
*crypt_stat
,
40 struct page
*dst_page
, int dst_offset
,
41 struct page
*src_page
, int src_offset
, int size
,
44 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat
*crypt_stat
,
45 struct page
*dst_page
, int dst_offset
,
46 struct page
*src_page
, int src_offset
, int size
,
51 * @dst: Buffer to take hex character representation of contents of
52 * src; must be at least of size (src_size * 2)
53 * @src: Buffer to be converted to a hex string respresentation
54 * @src_size: number of bytes to convert
56 void ecryptfs_to_hex(char *dst
, char *src
, size_t src_size
)
60 for (x
= 0; x
< src_size
; x
++)
61 sprintf(&dst
[x
* 2], "%.2x", (unsigned char)src
[x
]);
66 * @dst: Buffer to take the bytes from src hex; must be at least of
68 * @src: Buffer to be converted from a hex string respresentation to raw value
69 * @dst_size: size of dst buffer, or number of hex characters pairs to convert
71 void ecryptfs_from_hex(char *dst
, char *src
, int dst_size
)
76 for (x
= 0; x
< dst_size
; x
++) {
78 tmp
[1] = src
[x
* 2 + 1];
79 dst
[x
] = (unsigned char)simple_strtol(tmp
, NULL
, 16);
84 * ecryptfs_calculate_md5 - calculates the md5 of @src
85 * @dst: Pointer to 16 bytes of allocated memory
86 * @crypt_stat: Pointer to crypt_stat struct for the current inode
87 * @src: Data to be md5'd
88 * @len: Length of @src
90 * Uses the allocated crypto context that crypt_stat references to
91 * generate the MD5 sum of the contents of src.
93 static int ecryptfs_calculate_md5(char *dst
,
94 struct ecryptfs_crypt_stat
*crypt_stat
,
97 struct scatterlist sg
;
98 struct hash_desc desc
= {
99 .tfm
= crypt_stat
->hash_tfm
,
100 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
104 mutex_lock(&crypt_stat
->cs_hash_tfm_mutex
);
105 sg_init_one(&sg
, (u8
*)src
, len
);
107 desc
.tfm
= crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH
, 0,
109 if (IS_ERR(desc
.tfm
)) {
110 rc
= PTR_ERR(desc
.tfm
);
111 ecryptfs_printk(KERN_ERR
, "Error attempting to "
112 "allocate crypto context; rc = [%d]\n",
116 crypt_stat
->hash_tfm
= desc
.tfm
;
118 crypto_hash_init(&desc
);
119 crypto_hash_update(&desc
, &sg
, len
);
120 crypto_hash_final(&desc
, dst
);
121 mutex_unlock(&crypt_stat
->cs_hash_tfm_mutex
);
126 int ecryptfs_crypto_api_algify_cipher_name(char **algified_name
,
128 char *chaining_modifier
)
130 int cipher_name_len
= strlen(cipher_name
);
131 int chaining_modifier_len
= strlen(chaining_modifier
);
132 int algified_name_len
;
135 algified_name_len
= (chaining_modifier_len
+ cipher_name_len
+ 3);
136 (*algified_name
) = kmalloc(algified_name_len
, GFP_KERNEL
);
137 if (!(*algified_name
)) {
141 snprintf((*algified_name
), algified_name_len
, "%s(%s)",
142 chaining_modifier
, cipher_name
);
150 * @iv: destination for the derived iv vale
151 * @crypt_stat: Pointer to crypt_stat struct for the current inode
152 * @offset: Offset of the page whose's iv we are to derive
154 * Generate the initialization vector from the given root IV and page
157 * Returns zero on success; non-zero on error.
159 static int ecryptfs_derive_iv(char *iv
, struct ecryptfs_crypt_stat
*crypt_stat
,
163 char dst
[MD5_DIGEST_SIZE
];
164 char src
[ECRYPTFS_MAX_IV_BYTES
+ 16];
166 if (unlikely(ecryptfs_verbosity
> 0)) {
167 ecryptfs_printk(KERN_DEBUG
, "root iv:\n");
168 ecryptfs_dump_hex(crypt_stat
->root_iv
, crypt_stat
->iv_bytes
);
170 /* TODO: It is probably secure to just cast the least
171 * significant bits of the root IV into an unsigned long and
172 * add the offset to that rather than go through all this
173 * hashing business. -Halcrow */
174 memcpy(src
, crypt_stat
->root_iv
, crypt_stat
->iv_bytes
);
175 memset((src
+ crypt_stat
->iv_bytes
), 0, 16);
176 snprintf((src
+ crypt_stat
->iv_bytes
), 16, "%ld", offset
);
177 if (unlikely(ecryptfs_verbosity
> 0)) {
178 ecryptfs_printk(KERN_DEBUG
, "source:\n");
179 ecryptfs_dump_hex(src
, (crypt_stat
->iv_bytes
+ 16));
181 rc
= ecryptfs_calculate_md5(dst
, crypt_stat
, src
,
182 (crypt_stat
->iv_bytes
+ 16));
184 ecryptfs_printk(KERN_WARNING
, "Error attempting to compute "
185 "MD5 while generating IV for a page\n");
188 memcpy(iv
, dst
, crypt_stat
->iv_bytes
);
189 if (unlikely(ecryptfs_verbosity
> 0)) {
190 ecryptfs_printk(KERN_DEBUG
, "derived iv:\n");
191 ecryptfs_dump_hex(iv
, crypt_stat
->iv_bytes
);
198 * ecryptfs_init_crypt_stat
199 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
201 * Initialize the crypt_stat structure.
204 ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat
*crypt_stat
)
206 memset((void *)crypt_stat
, 0, sizeof(struct ecryptfs_crypt_stat
));
207 INIT_LIST_HEAD(&crypt_stat
->keysig_list
);
208 mutex_init(&crypt_stat
->keysig_list_mutex
);
209 mutex_init(&crypt_stat
->cs_mutex
);
210 mutex_init(&crypt_stat
->cs_tfm_mutex
);
211 mutex_init(&crypt_stat
->cs_hash_tfm_mutex
);
212 crypt_stat
->flags
|= ECRYPTFS_STRUCT_INITIALIZED
;
216 * ecryptfs_destroy_crypt_stat
217 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
219 * Releases all memory associated with a crypt_stat struct.
221 void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat
*crypt_stat
)
223 struct ecryptfs_key_sig
*key_sig
, *key_sig_tmp
;
226 crypto_free_blkcipher(crypt_stat
->tfm
);
227 if (crypt_stat
->hash_tfm
)
228 crypto_free_hash(crypt_stat
->hash_tfm
);
229 mutex_lock(&crypt_stat
->keysig_list_mutex
);
230 list_for_each_entry_safe(key_sig
, key_sig_tmp
,
231 &crypt_stat
->keysig_list
, crypt_stat_list
) {
232 list_del(&key_sig
->crypt_stat_list
);
233 kmem_cache_free(ecryptfs_key_sig_cache
, key_sig
);
235 mutex_unlock(&crypt_stat
->keysig_list_mutex
);
236 memset(crypt_stat
, 0, sizeof(struct ecryptfs_crypt_stat
));
239 void ecryptfs_destroy_mount_crypt_stat(
240 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
)
242 struct ecryptfs_global_auth_tok
*auth_tok
, *auth_tok_tmp
;
244 if (!(mount_crypt_stat
->flags
& ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED
))
246 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
247 list_for_each_entry_safe(auth_tok
, auth_tok_tmp
,
248 &mount_crypt_stat
->global_auth_tok_list
,
249 mount_crypt_stat_list
) {
250 list_del(&auth_tok
->mount_crypt_stat_list
);
251 mount_crypt_stat
->num_global_auth_toks
--;
252 if (auth_tok
->global_auth_tok_key
253 && !(auth_tok
->flags
& ECRYPTFS_AUTH_TOK_INVALID
))
254 key_put(auth_tok
->global_auth_tok_key
);
255 kmem_cache_free(ecryptfs_global_auth_tok_cache
, auth_tok
);
257 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
258 memset(mount_crypt_stat
, 0, sizeof(struct ecryptfs_mount_crypt_stat
));
262 * virt_to_scatterlist
263 * @addr: Virtual address
264 * @size: Size of data; should be an even multiple of the block size
265 * @sg: Pointer to scatterlist array; set to NULL to obtain only
266 * the number of scatterlist structs required in array
267 * @sg_size: Max array size
269 * Fills in a scatterlist array with page references for a passed
272 * Returns the number of scatterlist structs in array used
274 int virt_to_scatterlist(const void *addr
, int size
, struct scatterlist
*sg
,
280 int remainder_of_page
;
282 while (size
> 0 && i
< sg_size
) {
283 pg
= virt_to_page(addr
);
284 offset
= offset_in_page(addr
);
287 sg
[i
].offset
= offset
;
289 remainder_of_page
= PAGE_CACHE_SIZE
- offset
;
290 if (size
>= remainder_of_page
) {
292 sg
[i
].length
= remainder_of_page
;
293 addr
+= remainder_of_page
;
294 size
-= remainder_of_page
;
309 * encrypt_scatterlist
310 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
311 * @dest_sg: Destination of encrypted data
312 * @src_sg: Data to be encrypted
313 * @size: Length of data to be encrypted
314 * @iv: iv to use during encryption
316 * Returns the number of bytes encrypted; negative value on error
318 static int encrypt_scatterlist(struct ecryptfs_crypt_stat
*crypt_stat
,
319 struct scatterlist
*dest_sg
,
320 struct scatterlist
*src_sg
, int size
,
323 struct blkcipher_desc desc
= {
324 .tfm
= crypt_stat
->tfm
,
326 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
330 BUG_ON(!crypt_stat
|| !crypt_stat
->tfm
331 || !(crypt_stat
->flags
& ECRYPTFS_STRUCT_INITIALIZED
));
332 if (unlikely(ecryptfs_verbosity
> 0)) {
333 ecryptfs_printk(KERN_DEBUG
, "Key size [%d]; key:\n",
334 crypt_stat
->key_size
);
335 ecryptfs_dump_hex(crypt_stat
->key
,
336 crypt_stat
->key_size
);
338 /* Consider doing this once, when the file is opened */
339 mutex_lock(&crypt_stat
->cs_tfm_mutex
);
340 rc
= crypto_blkcipher_setkey(crypt_stat
->tfm
, crypt_stat
->key
,
341 crypt_stat
->key_size
);
343 ecryptfs_printk(KERN_ERR
, "Error setting key; rc = [%d]\n",
345 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
349 ecryptfs_printk(KERN_DEBUG
, "Encrypting [%d] bytes.\n", size
);
350 crypto_blkcipher_encrypt_iv(&desc
, dest_sg
, src_sg
, size
);
351 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
357 ecryptfs_extent_to_lwr_pg_idx_and_offset(unsigned long *lower_page_idx
,
359 struct ecryptfs_crypt_stat
*crypt_stat
,
360 unsigned long extent_num
)
362 unsigned long lower_extent_num
;
363 int extents_occupied_by_headers_at_front
;
364 int bytes_occupied_by_headers_at_front
;
366 int extents_per_page
;
368 bytes_occupied_by_headers_at_front
=
369 ( crypt_stat
->header_extent_size
370 * crypt_stat
->num_header_extents_at_front
);
371 extents_occupied_by_headers_at_front
=
372 ( bytes_occupied_by_headers_at_front
373 / crypt_stat
->extent_size
);
374 lower_extent_num
= extents_occupied_by_headers_at_front
+ extent_num
;
375 extents_per_page
= PAGE_CACHE_SIZE
/ crypt_stat
->extent_size
;
376 (*lower_page_idx
) = lower_extent_num
/ extents_per_page
;
377 extent_offset
= lower_extent_num
% extents_per_page
;
378 (*byte_offset
) = extent_offset
* crypt_stat
->extent_size
;
379 ecryptfs_printk(KERN_DEBUG
, " * crypt_stat->header_extent_size = "
380 "[%d]\n", crypt_stat
->header_extent_size
);
381 ecryptfs_printk(KERN_DEBUG
, " * crypt_stat->"
382 "num_header_extents_at_front = [%d]\n",
383 crypt_stat
->num_header_extents_at_front
);
384 ecryptfs_printk(KERN_DEBUG
, " * extents_occupied_by_headers_at_"
385 "front = [%d]\n", extents_occupied_by_headers_at_front
);
386 ecryptfs_printk(KERN_DEBUG
, " * lower_extent_num = [0x%.16x]\n",
388 ecryptfs_printk(KERN_DEBUG
, " * extents_per_page = [%d]\n",
390 ecryptfs_printk(KERN_DEBUG
, " * (*lower_page_idx) = [0x%.16x]\n",
392 ecryptfs_printk(KERN_DEBUG
, " * extent_offset = [%d]\n",
394 ecryptfs_printk(KERN_DEBUG
, " * (*byte_offset) = [%d]\n",
398 static int ecryptfs_write_out_page(struct ecryptfs_page_crypt_context
*ctx
,
399 struct page
*lower_page
,
400 struct inode
*lower_inode
,
401 int byte_offset_in_page
, int bytes_to_write
)
405 if (ctx
->mode
== ECRYPTFS_PREPARE_COMMIT_MODE
) {
406 rc
= ecryptfs_commit_lower_page(lower_page
, lower_inode
,
407 ctx
->param
.lower_file
,
411 ecryptfs_printk(KERN_ERR
, "Error calling lower "
412 "commit; rc = [%d]\n", rc
);
416 rc
= ecryptfs_writepage_and_release_lower_page(lower_page
,
420 ecryptfs_printk(KERN_ERR
, "Error calling lower "
421 "writepage(); rc = [%d]\n", rc
);
429 static int ecryptfs_read_in_page(struct ecryptfs_page_crypt_context
*ctx
,
430 struct page
**lower_page
,
431 struct inode
*lower_inode
,
432 unsigned long lower_page_idx
,
433 int byte_offset_in_page
)
437 if (ctx
->mode
== ECRYPTFS_PREPARE_COMMIT_MODE
) {
438 /* TODO: Limit this to only the data extents that are
440 rc
= ecryptfs_get_lower_page(lower_page
, lower_inode
,
441 ctx
->param
.lower_file
,
445 - byte_offset_in_page
));
448 KERN_ERR
, "Error attempting to grab, map, "
449 "and prepare_write lower page with index "
450 "[0x%.16x]; rc = [%d]\n", lower_page_idx
, rc
);
454 *lower_page
= grab_cache_page(lower_inode
->i_mapping
,
456 if (!(*lower_page
)) {
459 KERN_ERR
, "Error attempting to grab and map "
460 "lower page with index [0x%.16x]; rc = [%d]\n",
470 * ecryptfs_encrypt_page
471 * @ctx: The context of the page
473 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
474 * that eCryptfs pages may straddle the lower pages -- for instance,
475 * if the file was created on a machine with an 8K page size
476 * (resulting in an 8K header), and then the file is copied onto a
477 * host with a 32K page size, then when reading page 0 of the eCryptfs
478 * file, 24K of page 0 of the lower file will be read and decrypted,
479 * and then 8K of page 1 of the lower file will be read and decrypted.
481 * The actual operations performed on each page depends on the
482 * contents of the ecryptfs_page_crypt_context struct.
484 * Returns zero on success; negative on error
486 int ecryptfs_encrypt_page(struct ecryptfs_page_crypt_context
*ctx
)
488 char extent_iv
[ECRYPTFS_MAX_IV_BYTES
];
489 unsigned long base_extent
;
490 unsigned long extent_offset
= 0;
491 unsigned long lower_page_idx
= 0;
492 unsigned long prior_lower_page_idx
= 0;
493 struct page
*lower_page
;
494 struct inode
*lower_inode
;
495 struct ecryptfs_inode_info
*inode_info
;
496 struct ecryptfs_crypt_stat
*crypt_stat
;
498 int lower_byte_offset
= 0;
499 int orig_byte_offset
= 0;
500 int num_extents_per_page
;
501 #define ECRYPTFS_PAGE_STATE_UNREAD 0
502 #define ECRYPTFS_PAGE_STATE_READ 1
503 #define ECRYPTFS_PAGE_STATE_MODIFIED 2
504 #define ECRYPTFS_PAGE_STATE_WRITTEN 3
507 lower_inode
= ecryptfs_inode_to_lower(ctx
->page
->mapping
->host
);
508 inode_info
= ecryptfs_inode_to_private(ctx
->page
->mapping
->host
);
509 crypt_stat
= &inode_info
->crypt_stat
;
510 if (!(crypt_stat
->flags
& ECRYPTFS_ENCRYPTED
)) {
511 rc
= ecryptfs_copy_page_to_lower(ctx
->page
, lower_inode
,
512 ctx
->param
.lower_file
);
514 ecryptfs_printk(KERN_ERR
, "Error attempting to copy "
515 "page at index [0x%.16x]\n",
519 num_extents_per_page
= PAGE_CACHE_SIZE
/ crypt_stat
->extent_size
;
520 base_extent
= (ctx
->page
->index
* num_extents_per_page
);
521 page_state
= ECRYPTFS_PAGE_STATE_UNREAD
;
522 while (extent_offset
< num_extents_per_page
) {
523 ecryptfs_extent_to_lwr_pg_idx_and_offset(
524 &lower_page_idx
, &lower_byte_offset
, crypt_stat
,
525 (base_extent
+ extent_offset
));
526 if (prior_lower_page_idx
!= lower_page_idx
527 && page_state
== ECRYPTFS_PAGE_STATE_MODIFIED
) {
528 rc
= ecryptfs_write_out_page(ctx
, lower_page
,
532 - orig_byte_offset
));
534 ecryptfs_printk(KERN_ERR
, "Error attempting "
535 "to write out page; rc = [%d]"
539 page_state
= ECRYPTFS_PAGE_STATE_WRITTEN
;
541 if (page_state
== ECRYPTFS_PAGE_STATE_UNREAD
542 || page_state
== ECRYPTFS_PAGE_STATE_WRITTEN
) {
543 rc
= ecryptfs_read_in_page(ctx
, &lower_page
,
544 lower_inode
, lower_page_idx
,
547 ecryptfs_printk(KERN_ERR
, "Error attempting "
548 "to read in lower page with "
549 "index [0x%.16x]; rc = [%d]\n",
553 orig_byte_offset
= lower_byte_offset
;
554 prior_lower_page_idx
= lower_page_idx
;
555 page_state
= ECRYPTFS_PAGE_STATE_READ
;
557 BUG_ON(!(page_state
== ECRYPTFS_PAGE_STATE_MODIFIED
558 || page_state
== ECRYPTFS_PAGE_STATE_READ
));
559 rc
= ecryptfs_derive_iv(extent_iv
, crypt_stat
,
560 (base_extent
+ extent_offset
));
562 ecryptfs_printk(KERN_ERR
, "Error attempting to "
563 "derive IV for extent [0x%.16x]; "
565 (base_extent
+ extent_offset
), rc
);
568 if (unlikely(ecryptfs_verbosity
> 0)) {
569 ecryptfs_printk(KERN_DEBUG
, "Encrypting extent "
571 ecryptfs_dump_hex(extent_iv
, crypt_stat
->iv_bytes
);
572 ecryptfs_printk(KERN_DEBUG
, "First 8 bytes before "
574 ecryptfs_dump_hex((char *)
575 (page_address(ctx
->page
)
577 * crypt_stat
->extent_size
)), 8);
579 rc
= ecryptfs_encrypt_page_offset(
580 crypt_stat
, lower_page
, lower_byte_offset
, ctx
->page
,
581 (extent_offset
* crypt_stat
->extent_size
),
582 crypt_stat
->extent_size
, extent_iv
);
583 ecryptfs_printk(KERN_DEBUG
, "Encrypt extent [0x%.16x]; "
585 (base_extent
+ extent_offset
), rc
);
586 if (unlikely(ecryptfs_verbosity
> 0)) {
587 ecryptfs_printk(KERN_DEBUG
, "First 8 bytes after "
589 ecryptfs_dump_hex((char *)(page_address(lower_page
)
590 + lower_byte_offset
), 8);
592 page_state
= ECRYPTFS_PAGE_STATE_MODIFIED
;
595 BUG_ON(orig_byte_offset
!= 0);
596 rc
= ecryptfs_write_out_page(ctx
, lower_page
, lower_inode
, 0,
598 + crypt_stat
->extent_size
));
600 ecryptfs_printk(KERN_ERR
, "Error attempting to write out "
601 "page; rc = [%d]\n", rc
);
609 * ecryptfs_decrypt_page
610 * @file: The ecryptfs file
611 * @page: The page in ecryptfs to decrypt
613 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
614 * that eCryptfs pages may straddle the lower pages -- for instance,
615 * if the file was created on a machine with an 8K page size
616 * (resulting in an 8K header), and then the file is copied onto a
617 * host with a 32K page size, then when reading page 0 of the eCryptfs
618 * file, 24K of page 0 of the lower file will be read and decrypted,
619 * and then 8K of page 1 of the lower file will be read and decrypted.
621 * Returns zero on success; negative on error
623 int ecryptfs_decrypt_page(struct file
*file
, struct page
*page
)
625 char extent_iv
[ECRYPTFS_MAX_IV_BYTES
];
626 unsigned long base_extent
;
627 unsigned long extent_offset
= 0;
628 unsigned long lower_page_idx
= 0;
629 unsigned long prior_lower_page_idx
= 0;
630 struct page
*lower_page
;
631 char *lower_page_virt
= NULL
;
632 struct inode
*lower_inode
;
633 struct ecryptfs_crypt_stat
*crypt_stat
;
636 int num_extents_per_page
;
639 crypt_stat
= &(ecryptfs_inode_to_private(
640 page
->mapping
->host
)->crypt_stat
);
641 lower_inode
= ecryptfs_inode_to_lower(page
->mapping
->host
);
642 if (!(crypt_stat
->flags
& ECRYPTFS_ENCRYPTED
)) {
643 rc
= ecryptfs_do_readpage(file
, page
, page
->index
);
645 ecryptfs_printk(KERN_ERR
, "Error attempting to copy "
646 "page at index [0x%.16x]\n",
650 num_extents_per_page
= PAGE_CACHE_SIZE
/ crypt_stat
->extent_size
;
651 base_extent
= (page
->index
* num_extents_per_page
);
652 lower_page_virt
= kmem_cache_alloc(ecryptfs_lower_page_cache
,
654 if (!lower_page_virt
) {
656 ecryptfs_printk(KERN_ERR
, "Error getting page for encrypted "
660 lower_page
= virt_to_page(lower_page_virt
);
661 page_state
= ECRYPTFS_PAGE_STATE_UNREAD
;
662 while (extent_offset
< num_extents_per_page
) {
663 ecryptfs_extent_to_lwr_pg_idx_and_offset(
664 &lower_page_idx
, &byte_offset
, crypt_stat
,
665 (base_extent
+ extent_offset
));
666 if (prior_lower_page_idx
!= lower_page_idx
667 || page_state
== ECRYPTFS_PAGE_STATE_UNREAD
) {
668 rc
= ecryptfs_do_readpage(file
, lower_page
,
671 ecryptfs_printk(KERN_ERR
, "Error reading "
672 "lower encrypted page; rc = "
676 prior_lower_page_idx
= lower_page_idx
;
677 page_state
= ECRYPTFS_PAGE_STATE_READ
;
679 rc
= ecryptfs_derive_iv(extent_iv
, crypt_stat
,
680 (base_extent
+ extent_offset
));
682 ecryptfs_printk(KERN_ERR
, "Error attempting to "
683 "derive IV for extent [0x%.16x]; rc = "
685 (base_extent
+ extent_offset
), rc
);
688 if (unlikely(ecryptfs_verbosity
> 0)) {
689 ecryptfs_printk(KERN_DEBUG
, "Decrypting extent "
691 ecryptfs_dump_hex(extent_iv
, crypt_stat
->iv_bytes
);
692 ecryptfs_printk(KERN_DEBUG
, "First 8 bytes before "
694 ecryptfs_dump_hex((lower_page_virt
+ byte_offset
), 8);
696 rc
= ecryptfs_decrypt_page_offset(crypt_stat
, page
,
698 * crypt_stat
->extent_size
),
699 lower_page
, byte_offset
,
700 crypt_stat
->extent_size
,
702 if (rc
!= crypt_stat
->extent_size
) {
703 ecryptfs_printk(KERN_ERR
, "Error attempting to "
704 "decrypt extent [0x%.16x]\n",
705 (base_extent
+ extent_offset
));
709 if (unlikely(ecryptfs_verbosity
> 0)) {
710 ecryptfs_printk(KERN_DEBUG
, "First 8 bytes after "
712 ecryptfs_dump_hex((char *)(page_address(page
)
719 kmem_cache_free(ecryptfs_lower_page_cache
, lower_page_virt
);
724 * decrypt_scatterlist
726 * Returns the number of bytes decrypted; negative value on error
728 static int decrypt_scatterlist(struct ecryptfs_crypt_stat
*crypt_stat
,
729 struct scatterlist
*dest_sg
,
730 struct scatterlist
*src_sg
, int size
,
733 struct blkcipher_desc desc
= {
734 .tfm
= crypt_stat
->tfm
,
736 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
740 /* Consider doing this once, when the file is opened */
741 mutex_lock(&crypt_stat
->cs_tfm_mutex
);
742 rc
= crypto_blkcipher_setkey(crypt_stat
->tfm
, crypt_stat
->key
,
743 crypt_stat
->key_size
);
745 ecryptfs_printk(KERN_ERR
, "Error setting key; rc = [%d]\n",
747 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
751 ecryptfs_printk(KERN_DEBUG
, "Decrypting [%d] bytes.\n", size
);
752 rc
= crypto_blkcipher_decrypt_iv(&desc
, dest_sg
, src_sg
, size
);
753 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
755 ecryptfs_printk(KERN_ERR
, "Error decrypting; rc = [%d]\n",
765 * ecryptfs_encrypt_page_offset
767 * Returns the number of bytes encrypted
770 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat
*crypt_stat
,
771 struct page
*dst_page
, int dst_offset
,
772 struct page
*src_page
, int src_offset
, int size
,
775 struct scatterlist src_sg
, dst_sg
;
777 src_sg
.page
= src_page
;
778 src_sg
.offset
= src_offset
;
779 src_sg
.length
= size
;
780 dst_sg
.page
= dst_page
;
781 dst_sg
.offset
= dst_offset
;
782 dst_sg
.length
= size
;
783 return encrypt_scatterlist(crypt_stat
, &dst_sg
, &src_sg
, size
, iv
);
787 * ecryptfs_decrypt_page_offset
789 * Returns the number of bytes decrypted
792 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat
*crypt_stat
,
793 struct page
*dst_page
, int dst_offset
,
794 struct page
*src_page
, int src_offset
, int size
,
797 struct scatterlist src_sg
, dst_sg
;
799 src_sg
.page
= src_page
;
800 src_sg
.offset
= src_offset
;
801 src_sg
.length
= size
;
802 dst_sg
.page
= dst_page
;
803 dst_sg
.offset
= dst_offset
;
804 dst_sg
.length
= size
;
805 return decrypt_scatterlist(crypt_stat
, &dst_sg
, &src_sg
, size
, iv
);
808 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
811 * ecryptfs_init_crypt_ctx
812 * @crypt_stat: Uninitilized crypt stats structure
814 * Initialize the crypto context.
816 * TODO: Performance: Keep a cache of initialized cipher contexts;
817 * only init if needed
819 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat
*crypt_stat
)
824 if (!crypt_stat
->cipher
) {
825 ecryptfs_printk(KERN_ERR
, "No cipher specified\n");
828 ecryptfs_printk(KERN_DEBUG
,
829 "Initializing cipher [%s]; strlen = [%d]; "
830 "key_size_bits = [%d]\n",
831 crypt_stat
->cipher
, (int)strlen(crypt_stat
->cipher
),
832 crypt_stat
->key_size
<< 3);
833 if (crypt_stat
->tfm
) {
837 mutex_lock(&crypt_stat
->cs_tfm_mutex
);
838 rc
= ecryptfs_crypto_api_algify_cipher_name(&full_alg_name
,
839 crypt_stat
->cipher
, "cbc");
842 crypt_stat
->tfm
= crypto_alloc_blkcipher(full_alg_name
, 0,
844 kfree(full_alg_name
);
845 if (IS_ERR(crypt_stat
->tfm
)) {
846 rc
= PTR_ERR(crypt_stat
->tfm
);
847 ecryptfs_printk(KERN_ERR
, "cryptfs: init_crypt_ctx(): "
848 "Error initializing cipher [%s]\n",
850 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
853 crypto_blkcipher_set_flags(crypt_stat
->tfm
, CRYPTO_TFM_REQ_WEAK_KEY
);
854 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
860 static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat
*crypt_stat
)
864 crypt_stat
->extent_mask
= 0xFFFFFFFF;
865 crypt_stat
->extent_shift
= 0;
866 if (crypt_stat
->extent_size
== 0)
868 extent_size_tmp
= crypt_stat
->extent_size
;
869 while ((extent_size_tmp
& 0x01) == 0) {
870 extent_size_tmp
>>= 1;
871 crypt_stat
->extent_mask
<<= 1;
872 crypt_stat
->extent_shift
++;
876 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat
*crypt_stat
)
878 /* Default values; may be overwritten as we are parsing the
880 crypt_stat
->extent_size
= ECRYPTFS_DEFAULT_EXTENT_SIZE
;
881 set_extent_mask_and_shift(crypt_stat
);
882 crypt_stat
->iv_bytes
= ECRYPTFS_DEFAULT_IV_BYTES
;
883 if (PAGE_CACHE_SIZE
<= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
) {
884 crypt_stat
->header_extent_size
=
885 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
;
887 crypt_stat
->header_extent_size
= PAGE_CACHE_SIZE
;
888 if (crypt_stat
->flags
& ECRYPTFS_METADATA_IN_XATTR
)
889 crypt_stat
->num_header_extents_at_front
= 0;
891 crypt_stat
->num_header_extents_at_front
= 1;
895 * ecryptfs_compute_root_iv
898 * On error, sets the root IV to all 0's.
900 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat
*crypt_stat
)
903 char dst
[MD5_DIGEST_SIZE
];
905 BUG_ON(crypt_stat
->iv_bytes
> MD5_DIGEST_SIZE
);
906 BUG_ON(crypt_stat
->iv_bytes
<= 0);
907 if (!(crypt_stat
->flags
& ECRYPTFS_KEY_VALID
)) {
909 ecryptfs_printk(KERN_WARNING
, "Session key not valid; "
910 "cannot generate root IV\n");
913 rc
= ecryptfs_calculate_md5(dst
, crypt_stat
, crypt_stat
->key
,
914 crypt_stat
->key_size
);
916 ecryptfs_printk(KERN_WARNING
, "Error attempting to compute "
917 "MD5 while generating root IV\n");
920 memcpy(crypt_stat
->root_iv
, dst
, crypt_stat
->iv_bytes
);
923 memset(crypt_stat
->root_iv
, 0, crypt_stat
->iv_bytes
);
924 crypt_stat
->flags
|= ECRYPTFS_SECURITY_WARNING
;
929 static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat
*crypt_stat
)
931 get_random_bytes(crypt_stat
->key
, crypt_stat
->key_size
);
932 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
933 ecryptfs_compute_root_iv(crypt_stat
);
934 if (unlikely(ecryptfs_verbosity
> 0)) {
935 ecryptfs_printk(KERN_DEBUG
, "Generated new session key:\n");
936 ecryptfs_dump_hex(crypt_stat
->key
,
937 crypt_stat
->key_size
);
942 * ecryptfs_copy_mount_wide_flags_to_inode_flags
944 * This function propagates the mount-wide flags to individual inode
947 static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
948 struct ecryptfs_crypt_stat
*crypt_stat
,
949 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
)
951 if (mount_crypt_stat
->flags
& ECRYPTFS_XATTR_METADATA_ENABLED
)
952 crypt_stat
->flags
|= ECRYPTFS_METADATA_IN_XATTR
;
953 if (mount_crypt_stat
->flags
& ECRYPTFS_ENCRYPTED_VIEW_ENABLED
)
954 crypt_stat
->flags
|= ECRYPTFS_VIEW_AS_ENCRYPTED
;
957 static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
958 struct ecryptfs_crypt_stat
*crypt_stat
,
959 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
)
961 struct ecryptfs_global_auth_tok
*global_auth_tok
;
964 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
965 list_for_each_entry(global_auth_tok
,
966 &mount_crypt_stat
->global_auth_tok_list
,
967 mount_crypt_stat_list
) {
968 rc
= ecryptfs_add_keysig(crypt_stat
, global_auth_tok
->sig
);
970 printk(KERN_ERR
"Error adding keysig; rc = [%d]\n", rc
);
972 &mount_crypt_stat
->global_auth_tok_list_mutex
);
976 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
982 * ecryptfs_set_default_crypt_stat_vals
985 * Default values in the event that policy does not override them.
987 static void ecryptfs_set_default_crypt_stat_vals(
988 struct ecryptfs_crypt_stat
*crypt_stat
,
989 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
)
991 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat
,
993 ecryptfs_set_default_sizes(crypt_stat
);
994 strcpy(crypt_stat
->cipher
, ECRYPTFS_DEFAULT_CIPHER
);
995 crypt_stat
->key_size
= ECRYPTFS_DEFAULT_KEY_BYTES
;
996 crypt_stat
->flags
&= ~(ECRYPTFS_KEY_VALID
);
997 crypt_stat
->file_version
= ECRYPTFS_FILE_VERSION
;
998 crypt_stat
->mount_crypt_stat
= mount_crypt_stat
;
1002 * ecryptfs_new_file_context
1005 * If the crypto context for the file has not yet been established,
1006 * this is where we do that. Establishing a new crypto context
1007 * involves the following decisions:
1008 * - What cipher to use?
1009 * - What set of authentication tokens to use?
1010 * Here we just worry about getting enough information into the
1011 * authentication tokens so that we know that they are available.
1012 * We associate the available authentication tokens with the new file
1013 * via the set of signatures in the crypt_stat struct. Later, when
1014 * the headers are actually written out, we may again defer to
1015 * userspace to perform the encryption of the session key; for the
1016 * foreseeable future, this will be the case with public key packets.
1018 * Returns zero on success; non-zero otherwise
1020 /* Associate an authentication token(s) with the file */
1021 int ecryptfs_new_file_context(struct dentry
*ecryptfs_dentry
)
1023 struct ecryptfs_crypt_stat
*crypt_stat
=
1024 &ecryptfs_inode_to_private(ecryptfs_dentry
->d_inode
)->crypt_stat
;
1025 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1026 &ecryptfs_superblock_to_private(
1027 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
1028 int cipher_name_len
;
1031 ecryptfs_set_default_crypt_stat_vals(crypt_stat
, mount_crypt_stat
);
1032 crypt_stat
->flags
|= (ECRYPTFS_ENCRYPTED
| ECRYPTFS_KEY_VALID
);
1033 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat
,
1035 rc
= ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat
,
1038 printk(KERN_ERR
"Error attempting to copy mount-wide key sigs "
1039 "to the inode key sigs; rc = [%d]\n", rc
);
1043 strlen(mount_crypt_stat
->global_default_cipher_name
);
1044 memcpy(crypt_stat
->cipher
,
1045 mount_crypt_stat
->global_default_cipher_name
,
1047 crypt_stat
->cipher
[cipher_name_len
] = '\0';
1048 crypt_stat
->key_size
=
1049 mount_crypt_stat
->global_default_cipher_key_size
;
1050 ecryptfs_generate_new_key(crypt_stat
);
1051 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1053 ecryptfs_printk(KERN_ERR
, "Error initializing cryptographic "
1054 "context for cipher [%s]: rc = [%d]\n",
1055 crypt_stat
->cipher
, rc
);
1061 * contains_ecryptfs_marker - check for the ecryptfs marker
1062 * @data: The data block in which to check
1064 * Returns one if marker found; zero if not found
1066 static int contains_ecryptfs_marker(char *data
)
1070 memcpy(&m_1
, data
, 4);
1071 m_1
= be32_to_cpu(m_1
);
1072 memcpy(&m_2
, (data
+ 4), 4);
1073 m_2
= be32_to_cpu(m_2
);
1074 if ((m_1
^ MAGIC_ECRYPTFS_MARKER
) == m_2
)
1076 ecryptfs_printk(KERN_DEBUG
, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1077 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1
, m_2
,
1078 MAGIC_ECRYPTFS_MARKER
);
1079 ecryptfs_printk(KERN_DEBUG
, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1080 "[0x%.8x]\n", (m_1
^ MAGIC_ECRYPTFS_MARKER
));
1084 struct ecryptfs_flag_map_elem
{
1089 /* Add support for additional flags by adding elements here. */
1090 static struct ecryptfs_flag_map_elem ecryptfs_flag_map
[] = {
1091 {0x00000001, ECRYPTFS_ENABLE_HMAC
},
1092 {0x00000002, ECRYPTFS_ENCRYPTED
},
1093 {0x00000004, ECRYPTFS_METADATA_IN_XATTR
}
1097 * ecryptfs_process_flags
1099 * @page_virt: Source data to be parsed
1100 * @bytes_read: Updated with the number of bytes read
1102 * Returns zero on success; non-zero if the flag set is invalid
1104 static int ecryptfs_process_flags(struct ecryptfs_crypt_stat
*crypt_stat
,
1105 char *page_virt
, int *bytes_read
)
1111 memcpy(&flags
, page_virt
, 4);
1112 flags
= be32_to_cpu(flags
);
1113 for (i
= 0; i
< ((sizeof(ecryptfs_flag_map
)
1114 / sizeof(struct ecryptfs_flag_map_elem
))); i
++)
1115 if (flags
& ecryptfs_flag_map
[i
].file_flag
) {
1116 crypt_stat
->flags
|= ecryptfs_flag_map
[i
].local_flag
;
1118 crypt_stat
->flags
&= ~(ecryptfs_flag_map
[i
].local_flag
);
1119 /* Version is in top 8 bits of the 32-bit flag vector */
1120 crypt_stat
->file_version
= ((flags
>> 24) & 0xFF);
1126 * write_ecryptfs_marker
1127 * @page_virt: The pointer to in a page to begin writing the marker
1128 * @written: Number of bytes written
1130 * Marker = 0x3c81b7f5
1132 static void write_ecryptfs_marker(char *page_virt
, size_t *written
)
1136 get_random_bytes(&m_1
, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
/ 2));
1137 m_2
= (m_1
^ MAGIC_ECRYPTFS_MARKER
);
1138 m_1
= cpu_to_be32(m_1
);
1139 memcpy(page_virt
, &m_1
, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
/ 2));
1140 m_2
= cpu_to_be32(m_2
);
1141 memcpy(page_virt
+ (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
/ 2), &m_2
,
1142 (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
/ 2));
1143 (*written
) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
;
1147 write_ecryptfs_flags(char *page_virt
, struct ecryptfs_crypt_stat
*crypt_stat
,
1153 for (i
= 0; i
< ((sizeof(ecryptfs_flag_map
)
1154 / sizeof(struct ecryptfs_flag_map_elem
))); i
++)
1155 if (crypt_stat
->flags
& ecryptfs_flag_map
[i
].local_flag
)
1156 flags
|= ecryptfs_flag_map
[i
].file_flag
;
1157 /* Version is in top 8 bits of the 32-bit flag vector */
1158 flags
|= ((((u8
)crypt_stat
->file_version
) << 24) & 0xFF000000);
1159 flags
= cpu_to_be32(flags
);
1160 memcpy(page_virt
, &flags
, 4);
1164 struct ecryptfs_cipher_code_str_map_elem
{
1165 char cipher_str
[16];
1169 /* Add support for additional ciphers by adding elements here. The
1170 * cipher_code is whatever OpenPGP applicatoins use to identify the
1171 * ciphers. List in order of probability. */
1172 static struct ecryptfs_cipher_code_str_map_elem
1173 ecryptfs_cipher_code_str_map
[] = {
1174 {"aes",RFC2440_CIPHER_AES_128
},
1175 {"blowfish", RFC2440_CIPHER_BLOWFISH
},
1176 {"des3_ede", RFC2440_CIPHER_DES3_EDE
},
1177 {"cast5", RFC2440_CIPHER_CAST_5
},
1178 {"twofish", RFC2440_CIPHER_TWOFISH
},
1179 {"cast6", RFC2440_CIPHER_CAST_6
},
1180 {"aes", RFC2440_CIPHER_AES_192
},
1181 {"aes", RFC2440_CIPHER_AES_256
}
1185 * ecryptfs_code_for_cipher_string
1186 * @str: The string representing the cipher name
1188 * Returns zero on no match, or the cipher code on match
1190 u16
ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat
*crypt_stat
)
1194 struct ecryptfs_cipher_code_str_map_elem
*map
=
1195 ecryptfs_cipher_code_str_map
;
1197 if (strcmp(crypt_stat
->cipher
, "aes") == 0) {
1198 switch (crypt_stat
->key_size
) {
1200 code
= RFC2440_CIPHER_AES_128
;
1203 code
= RFC2440_CIPHER_AES_192
;
1206 code
= RFC2440_CIPHER_AES_256
;
1209 for (i
= 0; i
< ARRAY_SIZE(ecryptfs_cipher_code_str_map
); i
++)
1210 if (strcmp(crypt_stat
->cipher
, map
[i
].cipher_str
) == 0){
1211 code
= map
[i
].cipher_code
;
1219 * ecryptfs_cipher_code_to_string
1220 * @str: Destination to write out the cipher name
1221 * @cipher_code: The code to convert to cipher name string
1223 * Returns zero on success
1225 int ecryptfs_cipher_code_to_string(char *str
, u16 cipher_code
)
1231 for (i
= 0; i
< ARRAY_SIZE(ecryptfs_cipher_code_str_map
); i
++)
1232 if (cipher_code
== ecryptfs_cipher_code_str_map
[i
].cipher_code
)
1233 strcpy(str
, ecryptfs_cipher_code_str_map
[i
].cipher_str
);
1234 if (str
[0] == '\0') {
1235 ecryptfs_printk(KERN_WARNING
, "Cipher code not recognized: "
1236 "[%d]\n", cipher_code
);
1243 * ecryptfs_read_header_region
1248 * Returns zero on success; non-zero otherwise
1250 static int ecryptfs_read_header_region(char *data
, struct dentry
*dentry
,
1251 struct vfsmount
*mnt
)
1253 struct file
*lower_file
;
1257 if ((rc
= ecryptfs_open_lower_file(&lower_file
, dentry
, mnt
,
1260 "Error opening lower_file to read header region\n");
1263 lower_file
->f_pos
= 0;
1266 rc
= lower_file
->f_op
->read(lower_file
, (char __user
*)data
,
1267 ECRYPTFS_DEFAULT_EXTENT_SIZE
, &lower_file
->f_pos
);
1269 if ((rc
= ecryptfs_close_lower_file(lower_file
))) {
1270 printk(KERN_ERR
"Error closing lower_file\n");
1278 int ecryptfs_read_and_validate_header_region(char *data
, struct dentry
*dentry
,
1279 struct vfsmount
*mnt
)
1283 rc
= ecryptfs_read_header_region(data
, dentry
, mnt
);
1286 if (!contains_ecryptfs_marker(data
+ ECRYPTFS_FILE_SIZE_BYTES
))
1294 ecryptfs_write_header_metadata(char *virt
,
1295 struct ecryptfs_crypt_stat
*crypt_stat
,
1298 u32 header_extent_size
;
1299 u16 num_header_extents_at_front
;
1301 header_extent_size
= (u32
)crypt_stat
->header_extent_size
;
1302 num_header_extents_at_front
=
1303 (u16
)crypt_stat
->num_header_extents_at_front
;
1304 header_extent_size
= cpu_to_be32(header_extent_size
);
1305 memcpy(virt
, &header_extent_size
, 4);
1307 num_header_extents_at_front
= cpu_to_be16(num_header_extents_at_front
);
1308 memcpy(virt
, &num_header_extents_at_front
, 2);
1312 struct kmem_cache
*ecryptfs_header_cache_0
;
1313 struct kmem_cache
*ecryptfs_header_cache_1
;
1314 struct kmem_cache
*ecryptfs_header_cache_2
;
1317 * ecryptfs_write_headers_virt
1325 * Octets 0-7: Unencrypted file size (big-endian)
1326 * Octets 8-15: eCryptfs special marker
1327 * Octets 16-19: Flags
1328 * Octet 16: File format version number (between 0 and 255)
1329 * Octets 17-18: Reserved
1330 * Octet 19: Bit 1 (lsb): Reserved
1332 * Bits 3-8: Reserved
1333 * Octets 20-23: Header extent size (big-endian)
1334 * Octets 24-25: Number of header extents at front of file
1336 * Octet 26: Begin RFC 2440 authentication token packet set
1338 * Lower data (CBC encrypted)
1340 * Lower data (CBC encrypted)
1343 * Returns zero on success
1345 static int ecryptfs_write_headers_virt(char *page_virt
, size_t *size
,
1346 struct ecryptfs_crypt_stat
*crypt_stat
,
1347 struct dentry
*ecryptfs_dentry
)
1353 offset
= ECRYPTFS_FILE_SIZE_BYTES
;
1354 write_ecryptfs_marker((page_virt
+ offset
), &written
);
1356 write_ecryptfs_flags((page_virt
+ offset
), crypt_stat
, &written
);
1358 ecryptfs_write_header_metadata((page_virt
+ offset
), crypt_stat
,
1361 rc
= ecryptfs_generate_key_packet_set((page_virt
+ offset
), crypt_stat
,
1362 ecryptfs_dentry
, &written
,
1363 PAGE_CACHE_SIZE
- offset
);
1365 ecryptfs_printk(KERN_WARNING
, "Error generating key packet "
1366 "set; rc = [%d]\n", rc
);
1374 static int ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat
*crypt_stat
,
1375 struct file
*lower_file
,
1379 int current_header_page
;
1384 lower_file
->f_pos
= 0;
1387 size
= vfs_write(lower_file
, (char __user
*)page_virt
, PAGE_CACHE_SIZE
,
1388 &lower_file
->f_pos
);
1391 printk(KERN_ERR
"Error attempting to write lower page; "
1396 header_pages
= ((crypt_stat
->header_extent_size
1397 * crypt_stat
->num_header_extents_at_front
)
1399 memset(page_virt
, 0, PAGE_CACHE_SIZE
);
1400 current_header_page
= 1;
1401 while (current_header_page
< header_pages
) {
1402 size
= vfs_write(lower_file
, (char __user
*)page_virt
,
1403 PAGE_CACHE_SIZE
, &lower_file
->f_pos
);
1406 printk(KERN_ERR
"Error attempting to write lower page; "
1411 current_header_page
++;
1418 static int ecryptfs_write_metadata_to_xattr(struct dentry
*ecryptfs_dentry
,
1419 struct ecryptfs_crypt_stat
*crypt_stat
,
1420 char *page_virt
, size_t size
)
1424 rc
= ecryptfs_setxattr(ecryptfs_dentry
, ECRYPTFS_XATTR_NAME
, page_virt
,
1430 * ecryptfs_write_metadata
1431 * @lower_file: The lower file struct, which was returned from dentry_open
1433 * Write the file headers out. This will likely involve a userspace
1434 * callout, in which the session key is encrypted with one or more
1435 * public keys and/or the passphrase necessary to do the encryption is
1436 * retrieved via a prompt. Exactly what happens at this point should
1437 * be policy-dependent.
1439 * Returns zero on success; non-zero on error
1441 int ecryptfs_write_metadata(struct dentry
*ecryptfs_dentry
,
1442 struct file
*lower_file
)
1444 struct ecryptfs_crypt_stat
*crypt_stat
;
1449 crypt_stat
= &ecryptfs_inode_to_private(
1450 ecryptfs_dentry
->d_inode
)->crypt_stat
;
1451 if (likely(crypt_stat
->flags
& ECRYPTFS_ENCRYPTED
)) {
1452 if (!(crypt_stat
->flags
& ECRYPTFS_KEY_VALID
)) {
1453 ecryptfs_printk(KERN_DEBUG
, "Key is "
1454 "invalid; bailing out\n");
1460 ecryptfs_printk(KERN_WARNING
,
1461 "Called with crypt_stat->encrypted == 0\n");
1464 /* Released in this function */
1465 page_virt
= kmem_cache_zalloc(ecryptfs_header_cache_0
, GFP_USER
);
1467 ecryptfs_printk(KERN_ERR
, "Out of memory\n");
1471 rc
= ecryptfs_write_headers_virt(page_virt
, &size
, crypt_stat
,
1474 ecryptfs_printk(KERN_ERR
, "Error whilst writing headers\n");
1475 memset(page_virt
, 0, PAGE_CACHE_SIZE
);
1478 if (crypt_stat
->flags
& ECRYPTFS_METADATA_IN_XATTR
)
1479 rc
= ecryptfs_write_metadata_to_xattr(ecryptfs_dentry
,
1480 crypt_stat
, page_virt
,
1483 rc
= ecryptfs_write_metadata_to_contents(crypt_stat
, lower_file
,
1486 printk(KERN_ERR
"Error writing metadata out to lower file; "
1491 kmem_cache_free(ecryptfs_header_cache_0
, page_virt
);
1496 #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1497 #define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1498 static int parse_header_metadata(struct ecryptfs_crypt_stat
*crypt_stat
,
1499 char *virt
, int *bytes_read
,
1500 int validate_header_size
)
1503 u32 header_extent_size
;
1504 u16 num_header_extents_at_front
;
1506 memcpy(&header_extent_size
, virt
, 4);
1507 header_extent_size
= be32_to_cpu(header_extent_size
);
1509 memcpy(&num_header_extents_at_front
, virt
, 2);
1510 num_header_extents_at_front
= be16_to_cpu(num_header_extents_at_front
);
1511 crypt_stat
->header_extent_size
= (int)header_extent_size
;
1512 crypt_stat
->num_header_extents_at_front
=
1513 (int)num_header_extents_at_front
;
1515 if ((validate_header_size
== ECRYPTFS_VALIDATE_HEADER_SIZE
)
1516 && ((crypt_stat
->header_extent_size
1517 * crypt_stat
->num_header_extents_at_front
)
1518 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
)) {
1520 ecryptfs_printk(KERN_WARNING
, "Invalid header extent size: "
1521 "[%d]\n", crypt_stat
->header_extent_size
);
1527 * set_default_header_data
1529 * For version 0 file format; this function is only for backwards
1530 * compatibility for files created with the prior versions of
1533 static void set_default_header_data(struct ecryptfs_crypt_stat
*crypt_stat
)
1535 crypt_stat
->header_extent_size
= 4096;
1536 crypt_stat
->num_header_extents_at_front
= 1;
1540 * ecryptfs_read_headers_virt
1542 * Read/parse the header data. The header format is detailed in the
1543 * comment block for the ecryptfs_write_headers_virt() function.
1545 * Returns zero on success
1547 static int ecryptfs_read_headers_virt(char *page_virt
,
1548 struct ecryptfs_crypt_stat
*crypt_stat
,
1549 struct dentry
*ecryptfs_dentry
,
1550 int validate_header_size
)
1556 ecryptfs_set_default_sizes(crypt_stat
);
1557 crypt_stat
->mount_crypt_stat
= &ecryptfs_superblock_to_private(
1558 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
1559 offset
= ECRYPTFS_FILE_SIZE_BYTES
;
1560 rc
= contains_ecryptfs_marker(page_virt
+ offset
);
1565 offset
+= MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
;
1566 rc
= ecryptfs_process_flags(crypt_stat
, (page_virt
+ offset
),
1569 ecryptfs_printk(KERN_WARNING
, "Error processing flags\n");
1572 if (crypt_stat
->file_version
> ECRYPTFS_SUPPORTED_FILE_VERSION
) {
1573 ecryptfs_printk(KERN_WARNING
, "File version is [%d]; only "
1574 "file version [%d] is supported by this "
1575 "version of eCryptfs\n",
1576 crypt_stat
->file_version
,
1577 ECRYPTFS_SUPPORTED_FILE_VERSION
);
1581 offset
+= bytes_read
;
1582 if (crypt_stat
->file_version
>= 1) {
1583 rc
= parse_header_metadata(crypt_stat
, (page_virt
+ offset
),
1584 &bytes_read
, validate_header_size
);
1586 ecryptfs_printk(KERN_WARNING
, "Error reading header "
1587 "metadata; rc = [%d]\n", rc
);
1589 offset
+= bytes_read
;
1591 set_default_header_data(crypt_stat
);
1592 rc
= ecryptfs_parse_packet_set(crypt_stat
, (page_virt
+ offset
),
1599 * ecryptfs_read_xattr_region
1601 * Attempts to read the crypto metadata from the extended attribute
1602 * region of the lower file.
1604 int ecryptfs_read_xattr_region(char *page_virt
, struct dentry
*ecryptfs_dentry
)
1609 size
= ecryptfs_getxattr(ecryptfs_dentry
, ECRYPTFS_XATTR_NAME
,
1610 page_virt
, ECRYPTFS_DEFAULT_EXTENT_SIZE
);
1612 printk(KERN_DEBUG
"Error attempting to read the [%s] "
1613 "xattr from the lower file; return value = [%zd]\n",
1614 ECRYPTFS_XATTR_NAME
, size
);
1622 int ecryptfs_read_and_validate_xattr_region(char *page_virt
,
1623 struct dentry
*ecryptfs_dentry
)
1627 rc
= ecryptfs_read_xattr_region(page_virt
, ecryptfs_dentry
);
1630 if (!contains_ecryptfs_marker(page_virt
+ ECRYPTFS_FILE_SIZE_BYTES
)) {
1631 printk(KERN_WARNING
"Valid data found in [%s] xattr, but "
1632 "the marker is invalid\n", ECRYPTFS_XATTR_NAME
);
1640 * ecryptfs_read_metadata
1642 * Common entry point for reading file metadata. From here, we could
1643 * retrieve the header information from the header region of the file,
1644 * the xattr region of the file, or some other repostory that is
1645 * stored separately from the file itself. The current implementation
1646 * supports retrieving the metadata information from the file contents
1647 * and from the xattr region.
1649 * Returns zero if valid headers found and parsed; non-zero otherwise
1651 int ecryptfs_read_metadata(struct dentry
*ecryptfs_dentry
,
1652 struct file
*lower_file
)
1655 char *page_virt
= NULL
;
1658 struct ecryptfs_crypt_stat
*crypt_stat
=
1659 &ecryptfs_inode_to_private(ecryptfs_dentry
->d_inode
)->crypt_stat
;
1660 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1661 &ecryptfs_superblock_to_private(
1662 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
1664 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat
,
1666 /* Read the first page from the underlying file */
1667 page_virt
= kmem_cache_alloc(ecryptfs_header_cache_1
, GFP_USER
);
1670 ecryptfs_printk(KERN_ERR
, "Unable to allocate page_virt\n");
1673 lower_file
->f_pos
= 0;
1676 bytes_read
= lower_file
->f_op
->read(lower_file
,
1677 (char __user
*)page_virt
,
1678 ECRYPTFS_DEFAULT_EXTENT_SIZE
,
1679 &lower_file
->f_pos
);
1681 if (bytes_read
!= ECRYPTFS_DEFAULT_EXTENT_SIZE
) {
1685 rc
= ecryptfs_read_headers_virt(page_virt
, crypt_stat
,
1687 ECRYPTFS_VALIDATE_HEADER_SIZE
);
1689 rc
= ecryptfs_read_xattr_region(page_virt
,
1692 printk(KERN_DEBUG
"Valid eCryptfs headers not found in "
1693 "file header region or xattr region\n");
1697 rc
= ecryptfs_read_headers_virt(page_virt
, crypt_stat
,
1699 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE
);
1701 printk(KERN_DEBUG
"Valid eCryptfs headers not found in "
1702 "file xattr region either\n");
1705 if (crypt_stat
->mount_crypt_stat
->flags
1706 & ECRYPTFS_XATTR_METADATA_ENABLED
) {
1707 crypt_stat
->flags
|= ECRYPTFS_METADATA_IN_XATTR
;
1709 printk(KERN_WARNING
"Attempt to access file with "
1710 "crypto metadata only in the extended attribute "
1711 "region, but eCryptfs was mounted without "
1712 "xattr support enabled. eCryptfs will not treat "
1713 "this like an encrypted file.\n");
1719 memset(page_virt
, 0, PAGE_CACHE_SIZE
);
1720 kmem_cache_free(ecryptfs_header_cache_1
, page_virt
);
1726 * ecryptfs_encode_filename - converts a plaintext file name to cipher text
1727 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
1728 * @name: The plaintext name
1729 * @length: The length of the plaintext
1730 * @encoded_name: The encypted name
1732 * Encrypts and encodes a filename into something that constitutes a
1733 * valid filename for a filesystem, with printable characters.
1735 * We assume that we have a properly initialized crypto context,
1736 * pointed to by crypt_stat->tfm.
1738 * TODO: Implement filename decoding and decryption here, in place of
1739 * memcpy. We are keeping the framework around for now to (1)
1740 * facilitate testing of the components needed to implement filename
1741 * encryption and (2) to provide a code base from which other
1742 * developers in the community can easily implement this feature.
1744 * Returns the length of encoded filename; negative if error
1747 ecryptfs_encode_filename(struct ecryptfs_crypt_stat
*crypt_stat
,
1748 const char *name
, int length
, char **encoded_name
)
1752 (*encoded_name
) = kmalloc(length
+ 2, GFP_KERNEL
);
1753 if (!(*encoded_name
)) {
1757 /* TODO: Filename encryption is a scheduled feature for a
1758 * future version of eCryptfs. This function is here only for
1759 * the purpose of providing a framework for other developers
1760 * to easily implement filename encryption. Hint: Replace this
1761 * memcpy() with a call to encrypt and encode the
1762 * filename, the set the length accordingly. */
1763 memcpy((void *)(*encoded_name
), (void *)name
, length
);
1764 (*encoded_name
)[length
] = '\0';
1771 * ecryptfs_decode_filename - converts the cipher text name to plaintext
1772 * @crypt_stat: The crypt_stat struct associated with the file
1773 * @name: The filename in cipher text
1774 * @length: The length of the cipher text name
1775 * @decrypted_name: The plaintext name
1777 * Decodes and decrypts the filename.
1779 * We assume that we have a properly initialized crypto context,
1780 * pointed to by crypt_stat->tfm.
1782 * TODO: Implement filename decoding and decryption here, in place of
1783 * memcpy. We are keeping the framework around for now to (1)
1784 * facilitate testing of the components needed to implement filename
1785 * encryption and (2) to provide a code base from which other
1786 * developers in the community can easily implement this feature.
1788 * Returns the length of decoded filename; negative if error
1791 ecryptfs_decode_filename(struct ecryptfs_crypt_stat
*crypt_stat
,
1792 const char *name
, int length
, char **decrypted_name
)
1796 (*decrypted_name
) = kmalloc(length
+ 2, GFP_KERNEL
);
1797 if (!(*decrypted_name
)) {
1801 /* TODO: Filename encryption is a scheduled feature for a
1802 * future version of eCryptfs. This function is here only for
1803 * the purpose of providing a framework for other developers
1804 * to easily implement filename encryption. Hint: Replace this
1805 * memcpy() with a call to decode and decrypt the
1806 * filename, the set the length accordingly. */
1807 memcpy((void *)(*decrypted_name
), (void *)name
, length
);
1808 (*decrypted_name
)[length
+ 1] = '\0'; /* Only for convenience
1809 * in printing out the
1818 * ecryptfs_process_key_cipher - Perform key cipher initialization.
1819 * @key_tfm: Crypto context for key material, set by this function
1820 * @cipher_name: Name of the cipher
1821 * @key_size: Size of the key in bytes
1823 * Returns zero on success. Any crypto_tfm structs allocated here
1824 * should be released by other functions, such as on a superblock put
1825 * event, regardless of whether this function succeeds for fails.
1828 ecryptfs_process_key_cipher(struct crypto_blkcipher
**key_tfm
,
1829 char *cipher_name
, size_t *key_size
)
1831 char dummy_key
[ECRYPTFS_MAX_KEY_BYTES
];
1832 char *full_alg_name
;
1836 if (*key_size
> ECRYPTFS_MAX_KEY_BYTES
) {
1838 printk(KERN_ERR
"Requested key size is [%Zd] bytes; maximum "
1839 "allowable is [%d]\n", *key_size
, ECRYPTFS_MAX_KEY_BYTES
);
1842 rc
= ecryptfs_crypto_api_algify_cipher_name(&full_alg_name
, cipher_name
,
1846 *key_tfm
= crypto_alloc_blkcipher(full_alg_name
, 0, CRYPTO_ALG_ASYNC
);
1847 kfree(full_alg_name
);
1848 if (IS_ERR(*key_tfm
)) {
1849 rc
= PTR_ERR(*key_tfm
);
1850 printk(KERN_ERR
"Unable to allocate crypto cipher with name "
1851 "[%s]; rc = [%d]\n", cipher_name
, rc
);
1854 crypto_blkcipher_set_flags(*key_tfm
, CRYPTO_TFM_REQ_WEAK_KEY
);
1855 if (*key_size
== 0) {
1856 struct blkcipher_alg
*alg
= crypto_blkcipher_alg(*key_tfm
);
1858 *key_size
= alg
->max_keysize
;
1860 get_random_bytes(dummy_key
, *key_size
);
1861 rc
= crypto_blkcipher_setkey(*key_tfm
, dummy_key
, *key_size
);
1863 printk(KERN_ERR
"Error attempting to set key of size [%Zd] for "
1864 "cipher [%s]; rc = [%d]\n", *key_size
, cipher_name
, rc
);
1872 struct kmem_cache
*ecryptfs_key_tfm_cache
;
1873 struct list_head key_tfm_list
;
1874 struct mutex key_tfm_list_mutex
;
1876 int ecryptfs_init_crypto(void)
1878 mutex_init(&key_tfm_list_mutex
);
1879 INIT_LIST_HEAD(&key_tfm_list
);
1883 int ecryptfs_destroy_crypto(void)
1885 struct ecryptfs_key_tfm
*key_tfm
, *key_tfm_tmp
;
1887 mutex_lock(&key_tfm_list_mutex
);
1888 list_for_each_entry_safe(key_tfm
, key_tfm_tmp
, &key_tfm_list
,
1890 list_del(&key_tfm
->key_tfm_list
);
1891 if (key_tfm
->key_tfm
)
1892 crypto_free_blkcipher(key_tfm
->key_tfm
);
1893 kmem_cache_free(ecryptfs_key_tfm_cache
, key_tfm
);
1895 mutex_unlock(&key_tfm_list_mutex
);
1900 ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm
**key_tfm
, char *cipher_name
,
1903 struct ecryptfs_key_tfm
*tmp_tfm
;
1906 tmp_tfm
= kmem_cache_alloc(ecryptfs_key_tfm_cache
, GFP_KERNEL
);
1907 if (key_tfm
!= NULL
)
1908 (*key_tfm
) = tmp_tfm
;
1911 printk(KERN_ERR
"Error attempting to allocate from "
1912 "ecryptfs_key_tfm_cache\n");
1915 mutex_init(&tmp_tfm
->key_tfm_mutex
);
1916 strncpy(tmp_tfm
->cipher_name
, cipher_name
,
1917 ECRYPTFS_MAX_CIPHER_NAME_SIZE
);
1918 tmp_tfm
->key_size
= key_size
;
1919 if ((rc
= ecryptfs_process_key_cipher(&tmp_tfm
->key_tfm
,
1920 tmp_tfm
->cipher_name
,
1921 &tmp_tfm
->key_size
))) {
1922 printk(KERN_ERR
"Error attempting to initialize key TFM "
1923 "cipher with name = [%s]; rc = [%d]\n",
1924 tmp_tfm
->cipher_name
, rc
);
1925 kmem_cache_free(ecryptfs_key_tfm_cache
, tmp_tfm
);
1926 if (key_tfm
!= NULL
)
1930 mutex_lock(&key_tfm_list_mutex
);
1931 list_add(&tmp_tfm
->key_tfm_list
, &key_tfm_list
);
1932 mutex_unlock(&key_tfm_list_mutex
);
1937 int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher
**tfm
,
1938 struct mutex
**tfm_mutex
,
1941 struct ecryptfs_key_tfm
*key_tfm
;
1945 (*tfm_mutex
) = NULL
;
1946 mutex_lock(&key_tfm_list_mutex
);
1947 list_for_each_entry(key_tfm
, &key_tfm_list
, key_tfm_list
) {
1948 if (strcmp(key_tfm
->cipher_name
, cipher_name
) == 0) {
1949 (*tfm
) = key_tfm
->key_tfm
;
1950 (*tfm_mutex
) = &key_tfm
->key_tfm_mutex
;
1951 mutex_unlock(&key_tfm_list_mutex
);
1955 mutex_unlock(&key_tfm_list_mutex
);
1956 if ((rc
= ecryptfs_add_new_key_tfm(&key_tfm
, cipher_name
, 0))) {
1957 printk(KERN_ERR
"Error adding new key_tfm to list; rc = [%d]\n",
1961 (*tfm
) = key_tfm
->key_tfm
;
1962 (*tfm_mutex
) = &key_tfm
->key_tfm_mutex
;