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 static 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 extent whose 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, "%lld", 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_lower_offset_for_extent
359 * Convert an eCryptfs page index into a lower byte offset
361 void ecryptfs_lower_offset_for_extent(loff_t
*offset
, loff_t extent_num
,
362 struct ecryptfs_crypt_stat
*crypt_stat
)
364 (*offset
) = ((crypt_stat
->extent_size
365 * crypt_stat
->num_header_extents_at_front
)
366 + (crypt_stat
->extent_size
* extent_num
));
370 * ecryptfs_encrypt_extent
371 * @enc_extent_page: Allocated page into which to encrypt the data in
373 * @crypt_stat: crypt_stat containing cryptographic context for the
374 * encryption operation
375 * @page: Page containing plaintext data extent to encrypt
376 * @extent_offset: Page extent offset for use in generating IV
378 * Encrypts one extent of data.
380 * Return zero on success; non-zero otherwise
382 static int ecryptfs_encrypt_extent(struct page
*enc_extent_page
,
383 struct ecryptfs_crypt_stat
*crypt_stat
,
385 unsigned long extent_offset
)
388 char extent_iv
[ECRYPTFS_MAX_IV_BYTES
];
391 extent_base
= (((loff_t
)page
->index
)
392 * (PAGE_CACHE_SIZE
/ crypt_stat
->extent_size
));
393 rc
= ecryptfs_derive_iv(extent_iv
, crypt_stat
,
394 (extent_base
+ extent_offset
));
396 ecryptfs_printk(KERN_ERR
, "Error attempting to "
397 "derive IV for extent [0x%.16x]; "
398 "rc = [%d]\n", (extent_base
+ extent_offset
),
402 if (unlikely(ecryptfs_verbosity
> 0)) {
403 ecryptfs_printk(KERN_DEBUG
, "Encrypting extent "
405 ecryptfs_dump_hex(extent_iv
, crypt_stat
->iv_bytes
);
406 ecryptfs_printk(KERN_DEBUG
, "First 8 bytes before "
408 ecryptfs_dump_hex((char *)
410 + (extent_offset
* crypt_stat
->extent_size
)),
413 rc
= ecryptfs_encrypt_page_offset(crypt_stat
, enc_extent_page
, 0,
415 * crypt_stat
->extent_size
),
416 crypt_stat
->extent_size
, extent_iv
);
418 printk(KERN_ERR
"%s: Error attempting to encrypt page with "
419 "page->index = [%ld], extent_offset = [%ld]; "
420 "rc = [%d]\n", __FUNCTION__
, page
->index
, extent_offset
,
425 if (unlikely(ecryptfs_verbosity
> 0)) {
426 ecryptfs_printk(KERN_DEBUG
, "Encrypt extent [0x%.16x]; "
427 "rc = [%d]\n", (extent_base
+ extent_offset
),
429 ecryptfs_printk(KERN_DEBUG
, "First 8 bytes after "
431 ecryptfs_dump_hex((char *)(page_address(enc_extent_page
)), 8);
438 * ecryptfs_encrypt_page
439 * @page: Page mapped from the eCryptfs inode for the file; contains
440 * decrypted content that needs to be encrypted (to a temporary
441 * page; not in place) and written out to the lower file
443 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
444 * that eCryptfs pages may straddle the lower pages -- for instance,
445 * if the file was created on a machine with an 8K page size
446 * (resulting in an 8K header), and then the file is copied onto a
447 * host with a 32K page size, then when reading page 0 of the eCryptfs
448 * file, 24K of page 0 of the lower file will be read and decrypted,
449 * and then 8K of page 1 of the lower file will be read and decrypted.
451 * Returns zero on success; negative on error
453 int ecryptfs_encrypt_page(struct page
*page
)
455 struct inode
*ecryptfs_inode
;
456 struct ecryptfs_crypt_stat
*crypt_stat
;
457 char *enc_extent_virt
= NULL
;
458 struct page
*enc_extent_page
;
459 loff_t extent_offset
;
462 ecryptfs_inode
= page
->mapping
->host
;
464 &(ecryptfs_inode_to_private(ecryptfs_inode
)->crypt_stat
);
465 if (!(crypt_stat
->flags
& ECRYPTFS_ENCRYPTED
)) {
466 rc
= ecryptfs_write_lower_page_segment(ecryptfs_inode
, page
,
469 printk(KERN_ERR
"%s: Error attempting to copy "
470 "page at index [%ld]\n", __FUNCTION__
,
474 enc_extent_virt
= kmalloc(PAGE_CACHE_SIZE
, GFP_USER
);
475 if (!enc_extent_virt
) {
477 ecryptfs_printk(KERN_ERR
, "Error allocating memory for "
478 "encrypted extent\n");
481 enc_extent_page
= virt_to_page(enc_extent_virt
);
482 for (extent_offset
= 0;
483 extent_offset
< (PAGE_CACHE_SIZE
/ crypt_stat
->extent_size
);
487 rc
= ecryptfs_encrypt_extent(enc_extent_page
, crypt_stat
, page
,
490 printk(KERN_ERR
"%s: Error encrypting extent; "
491 "rc = [%d]\n", __FUNCTION__
, rc
);
494 ecryptfs_lower_offset_for_extent(
495 &offset
, ((((loff_t
)page
->index
)
497 / crypt_stat
->extent_size
))
498 + extent_offset
), crypt_stat
);
499 rc
= ecryptfs_write_lower(ecryptfs_inode
, enc_extent_virt
,
500 offset
, crypt_stat
->extent_size
);
502 ecryptfs_printk(KERN_ERR
, "Error attempting "
503 "to write lower page; rc = [%d]"
510 kfree(enc_extent_virt
);
514 static int ecryptfs_decrypt_extent(struct page
*page
,
515 struct ecryptfs_crypt_stat
*crypt_stat
,
516 struct page
*enc_extent_page
,
517 unsigned long extent_offset
)
520 char extent_iv
[ECRYPTFS_MAX_IV_BYTES
];
523 extent_base
= (((loff_t
)page
->index
)
524 * (PAGE_CACHE_SIZE
/ crypt_stat
->extent_size
));
525 rc
= ecryptfs_derive_iv(extent_iv
, crypt_stat
,
526 (extent_base
+ extent_offset
));
528 ecryptfs_printk(KERN_ERR
, "Error attempting to "
529 "derive IV for extent [0x%.16x]; "
530 "rc = [%d]\n", (extent_base
+ extent_offset
),
534 if (unlikely(ecryptfs_verbosity
> 0)) {
535 ecryptfs_printk(KERN_DEBUG
, "Decrypting extent "
537 ecryptfs_dump_hex(extent_iv
, crypt_stat
->iv_bytes
);
538 ecryptfs_printk(KERN_DEBUG
, "First 8 bytes before "
540 ecryptfs_dump_hex((char *)
541 (page_address(enc_extent_page
)
542 + (extent_offset
* crypt_stat
->extent_size
)),
545 rc
= ecryptfs_decrypt_page_offset(crypt_stat
, page
,
547 * crypt_stat
->extent_size
),
549 crypt_stat
->extent_size
, extent_iv
);
551 printk(KERN_ERR
"%s: Error attempting to decrypt to page with "
552 "page->index = [%ld], extent_offset = [%ld]; "
553 "rc = [%d]\n", __FUNCTION__
, page
->index
, extent_offset
,
558 if (unlikely(ecryptfs_verbosity
> 0)) {
559 ecryptfs_printk(KERN_DEBUG
, "Decrypt extent [0x%.16x]; "
560 "rc = [%d]\n", (extent_base
+ extent_offset
),
562 ecryptfs_printk(KERN_DEBUG
, "First 8 bytes after "
564 ecryptfs_dump_hex((char *)(page_address(page
)
566 * crypt_stat
->extent_size
)), 8);
573 * ecryptfs_decrypt_page
574 * @page: Page mapped from the eCryptfs inode for the file; data read
575 * and decrypted from the lower file will be written into this
578 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
579 * that eCryptfs pages may straddle the lower pages -- for instance,
580 * if the file was created on a machine with an 8K page size
581 * (resulting in an 8K header), and then the file is copied onto a
582 * host with a 32K page size, then when reading page 0 of the eCryptfs
583 * file, 24K of page 0 of the lower file will be read and decrypted,
584 * and then 8K of page 1 of the lower file will be read and decrypted.
586 * Returns zero on success; negative on error
588 int ecryptfs_decrypt_page(struct page
*page
)
590 struct inode
*ecryptfs_inode
;
591 struct ecryptfs_crypt_stat
*crypt_stat
;
592 char *enc_extent_virt
= NULL
;
593 struct page
*enc_extent_page
;
594 unsigned long extent_offset
;
597 ecryptfs_inode
= page
->mapping
->host
;
599 &(ecryptfs_inode_to_private(ecryptfs_inode
)->crypt_stat
);
600 if (!(crypt_stat
->flags
& ECRYPTFS_ENCRYPTED
)) {
601 rc
= ecryptfs_read_lower_page_segment(page
, page
->index
, 0,
605 printk(KERN_ERR
"%s: Error attempting to copy "
606 "page at index [%ld]\n", __FUNCTION__
,
608 goto out_clear_uptodate
;
610 enc_extent_virt
= kmalloc(PAGE_CACHE_SIZE
, GFP_USER
);
611 if (!enc_extent_virt
) {
613 ecryptfs_printk(KERN_ERR
, "Error allocating memory for "
614 "encrypted extent\n");
615 goto out_clear_uptodate
;
617 enc_extent_page
= virt_to_page(enc_extent_virt
);
618 for (extent_offset
= 0;
619 extent_offset
< (PAGE_CACHE_SIZE
/ crypt_stat
->extent_size
);
623 ecryptfs_lower_offset_for_extent(
624 &offset
, ((page
->index
* (PAGE_CACHE_SIZE
625 / crypt_stat
->extent_size
))
626 + extent_offset
), crypt_stat
);
627 rc
= ecryptfs_read_lower(enc_extent_virt
, offset
,
628 crypt_stat
->extent_size
,
631 ecryptfs_printk(KERN_ERR
, "Error attempting "
632 "to read lower page; rc = [%d]"
634 goto out_clear_uptodate
;
636 rc
= ecryptfs_decrypt_extent(page
, crypt_stat
, enc_extent_page
,
639 printk(KERN_ERR
"%s: Error encrypting extent; "
640 "rc = [%d]\n", __FUNCTION__
, rc
);
641 goto out_clear_uptodate
;
645 SetPageUptodate(page
);
648 ClearPageUptodate(page
);
650 kfree(enc_extent_virt
);
655 * decrypt_scatterlist
656 * @crypt_stat: Cryptographic context
657 * @dest_sg: The destination scatterlist to decrypt into
658 * @src_sg: The source scatterlist to decrypt from
659 * @size: The number of bytes to decrypt
660 * @iv: The initialization vector to use for the decryption
662 * Returns the number of bytes decrypted; negative value on error
664 static int decrypt_scatterlist(struct ecryptfs_crypt_stat
*crypt_stat
,
665 struct scatterlist
*dest_sg
,
666 struct scatterlist
*src_sg
, int size
,
669 struct blkcipher_desc desc
= {
670 .tfm
= crypt_stat
->tfm
,
672 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
676 /* Consider doing this once, when the file is opened */
677 mutex_lock(&crypt_stat
->cs_tfm_mutex
);
678 rc
= crypto_blkcipher_setkey(crypt_stat
->tfm
, crypt_stat
->key
,
679 crypt_stat
->key_size
);
681 ecryptfs_printk(KERN_ERR
, "Error setting key; rc = [%d]\n",
683 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
687 ecryptfs_printk(KERN_DEBUG
, "Decrypting [%d] bytes.\n", size
);
688 rc
= crypto_blkcipher_decrypt_iv(&desc
, dest_sg
, src_sg
, size
);
689 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
691 ecryptfs_printk(KERN_ERR
, "Error decrypting; rc = [%d]\n",
701 * ecryptfs_encrypt_page_offset
702 * @crypt_stat: The cryptographic context
703 * @dst_page: The page to encrypt into
704 * @dst_offset: The offset in the page to encrypt into
705 * @src_page: The page to encrypt from
706 * @src_offset: The offset in the page to encrypt from
707 * @size: The number of bytes to encrypt
708 * @iv: The initialization vector to use for the encryption
710 * Returns the number of bytes encrypted
713 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat
*crypt_stat
,
714 struct page
*dst_page
, int dst_offset
,
715 struct page
*src_page
, int src_offset
, int size
,
718 struct scatterlist src_sg
, dst_sg
;
720 src_sg
.page
= src_page
;
721 src_sg
.offset
= src_offset
;
722 src_sg
.length
= size
;
723 dst_sg
.page
= dst_page
;
724 dst_sg
.offset
= dst_offset
;
725 dst_sg
.length
= size
;
726 return encrypt_scatterlist(crypt_stat
, &dst_sg
, &src_sg
, size
, iv
);
730 * ecryptfs_decrypt_page_offset
731 * @crypt_stat: The cryptographic context
732 * @dst_page: The page to decrypt into
733 * @dst_offset: The offset in the page to decrypt into
734 * @src_page: The page to decrypt from
735 * @src_offset: The offset in the page to decrypt from
736 * @size: The number of bytes to decrypt
737 * @iv: The initialization vector to use for the decryption
739 * Returns the number of bytes decrypted
742 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat
*crypt_stat
,
743 struct page
*dst_page
, int dst_offset
,
744 struct page
*src_page
, int src_offset
, int size
,
747 struct scatterlist src_sg
, dst_sg
;
749 src_sg
.page
= src_page
;
750 src_sg
.offset
= src_offset
;
751 src_sg
.length
= size
;
752 dst_sg
.page
= dst_page
;
753 dst_sg
.offset
= dst_offset
;
754 dst_sg
.length
= size
;
755 return decrypt_scatterlist(crypt_stat
, &dst_sg
, &src_sg
, size
, iv
);
758 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
761 * ecryptfs_init_crypt_ctx
762 * @crypt_stat: Uninitilized crypt stats structure
764 * Initialize the crypto context.
766 * TODO: Performance: Keep a cache of initialized cipher contexts;
767 * only init if needed
769 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat
*crypt_stat
)
774 if (!crypt_stat
->cipher
) {
775 ecryptfs_printk(KERN_ERR
, "No cipher specified\n");
778 ecryptfs_printk(KERN_DEBUG
,
779 "Initializing cipher [%s]; strlen = [%d]; "
780 "key_size_bits = [%d]\n",
781 crypt_stat
->cipher
, (int)strlen(crypt_stat
->cipher
),
782 crypt_stat
->key_size
<< 3);
783 if (crypt_stat
->tfm
) {
787 mutex_lock(&crypt_stat
->cs_tfm_mutex
);
788 rc
= ecryptfs_crypto_api_algify_cipher_name(&full_alg_name
,
789 crypt_stat
->cipher
, "cbc");
792 crypt_stat
->tfm
= crypto_alloc_blkcipher(full_alg_name
, 0,
794 kfree(full_alg_name
);
795 if (IS_ERR(crypt_stat
->tfm
)) {
796 rc
= PTR_ERR(crypt_stat
->tfm
);
797 ecryptfs_printk(KERN_ERR
, "cryptfs: init_crypt_ctx(): "
798 "Error initializing cipher [%s]\n",
800 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
803 crypto_blkcipher_set_flags(crypt_stat
->tfm
, CRYPTO_TFM_REQ_WEAK_KEY
);
804 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
810 static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat
*crypt_stat
)
814 crypt_stat
->extent_mask
= 0xFFFFFFFF;
815 crypt_stat
->extent_shift
= 0;
816 if (crypt_stat
->extent_size
== 0)
818 extent_size_tmp
= crypt_stat
->extent_size
;
819 while ((extent_size_tmp
& 0x01) == 0) {
820 extent_size_tmp
>>= 1;
821 crypt_stat
->extent_mask
<<= 1;
822 crypt_stat
->extent_shift
++;
826 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat
*crypt_stat
)
828 /* Default values; may be overwritten as we are parsing the
830 crypt_stat
->extent_size
= ECRYPTFS_DEFAULT_EXTENT_SIZE
;
831 set_extent_mask_and_shift(crypt_stat
);
832 crypt_stat
->iv_bytes
= ECRYPTFS_DEFAULT_IV_BYTES
;
833 if (crypt_stat
->flags
& ECRYPTFS_METADATA_IN_XATTR
)
834 crypt_stat
->num_header_extents_at_front
= 0;
836 if (PAGE_CACHE_SIZE
<= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
)
837 crypt_stat
->num_header_extents_at_front
=
838 (ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
839 / crypt_stat
->extent_size
);
841 crypt_stat
->num_header_extents_at_front
=
842 (PAGE_CACHE_SIZE
/ crypt_stat
->extent_size
);
847 * ecryptfs_compute_root_iv
850 * On error, sets the root IV to all 0's.
852 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat
*crypt_stat
)
855 char dst
[MD5_DIGEST_SIZE
];
857 BUG_ON(crypt_stat
->iv_bytes
> MD5_DIGEST_SIZE
);
858 BUG_ON(crypt_stat
->iv_bytes
<= 0);
859 if (!(crypt_stat
->flags
& ECRYPTFS_KEY_VALID
)) {
861 ecryptfs_printk(KERN_WARNING
, "Session key not valid; "
862 "cannot generate root IV\n");
865 rc
= ecryptfs_calculate_md5(dst
, crypt_stat
, crypt_stat
->key
,
866 crypt_stat
->key_size
);
868 ecryptfs_printk(KERN_WARNING
, "Error attempting to compute "
869 "MD5 while generating root IV\n");
872 memcpy(crypt_stat
->root_iv
, dst
, crypt_stat
->iv_bytes
);
875 memset(crypt_stat
->root_iv
, 0, crypt_stat
->iv_bytes
);
876 crypt_stat
->flags
|= ECRYPTFS_SECURITY_WARNING
;
881 static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat
*crypt_stat
)
883 get_random_bytes(crypt_stat
->key
, crypt_stat
->key_size
);
884 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
885 ecryptfs_compute_root_iv(crypt_stat
);
886 if (unlikely(ecryptfs_verbosity
> 0)) {
887 ecryptfs_printk(KERN_DEBUG
, "Generated new session key:\n");
888 ecryptfs_dump_hex(crypt_stat
->key
,
889 crypt_stat
->key_size
);
894 * ecryptfs_copy_mount_wide_flags_to_inode_flags
895 * @crypt_stat: The inode's cryptographic context
896 * @mount_crypt_stat: The mount point's cryptographic context
898 * This function propagates the mount-wide flags to individual inode
901 static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
902 struct ecryptfs_crypt_stat
*crypt_stat
,
903 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
)
905 if (mount_crypt_stat
->flags
& ECRYPTFS_XATTR_METADATA_ENABLED
)
906 crypt_stat
->flags
|= ECRYPTFS_METADATA_IN_XATTR
;
907 if (mount_crypt_stat
->flags
& ECRYPTFS_ENCRYPTED_VIEW_ENABLED
)
908 crypt_stat
->flags
|= ECRYPTFS_VIEW_AS_ENCRYPTED
;
911 static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
912 struct ecryptfs_crypt_stat
*crypt_stat
,
913 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
)
915 struct ecryptfs_global_auth_tok
*global_auth_tok
;
918 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
919 list_for_each_entry(global_auth_tok
,
920 &mount_crypt_stat
->global_auth_tok_list
,
921 mount_crypt_stat_list
) {
922 rc
= ecryptfs_add_keysig(crypt_stat
, global_auth_tok
->sig
);
924 printk(KERN_ERR
"Error adding keysig; rc = [%d]\n", rc
);
926 &mount_crypt_stat
->global_auth_tok_list_mutex
);
930 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
936 * ecryptfs_set_default_crypt_stat_vals
937 * @crypt_stat: The inode's cryptographic context
938 * @mount_crypt_stat: The mount point's cryptographic context
940 * Default values in the event that policy does not override them.
942 static void ecryptfs_set_default_crypt_stat_vals(
943 struct ecryptfs_crypt_stat
*crypt_stat
,
944 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
)
946 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat
,
948 ecryptfs_set_default_sizes(crypt_stat
);
949 strcpy(crypt_stat
->cipher
, ECRYPTFS_DEFAULT_CIPHER
);
950 crypt_stat
->key_size
= ECRYPTFS_DEFAULT_KEY_BYTES
;
951 crypt_stat
->flags
&= ~(ECRYPTFS_KEY_VALID
);
952 crypt_stat
->file_version
= ECRYPTFS_FILE_VERSION
;
953 crypt_stat
->mount_crypt_stat
= mount_crypt_stat
;
957 * ecryptfs_new_file_context
958 * @ecryptfs_dentry: The eCryptfs dentry
960 * If the crypto context for the file has not yet been established,
961 * this is where we do that. Establishing a new crypto context
962 * involves the following decisions:
963 * - What cipher to use?
964 * - What set of authentication tokens to use?
965 * Here we just worry about getting enough information into the
966 * authentication tokens so that we know that they are available.
967 * We associate the available authentication tokens with the new file
968 * via the set of signatures in the crypt_stat struct. Later, when
969 * the headers are actually written out, we may again defer to
970 * userspace to perform the encryption of the session key; for the
971 * foreseeable future, this will be the case with public key packets.
973 * Returns zero on success; non-zero otherwise
975 int ecryptfs_new_file_context(struct dentry
*ecryptfs_dentry
)
977 struct ecryptfs_crypt_stat
*crypt_stat
=
978 &ecryptfs_inode_to_private(ecryptfs_dentry
->d_inode
)->crypt_stat
;
979 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
980 &ecryptfs_superblock_to_private(
981 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
985 ecryptfs_set_default_crypt_stat_vals(crypt_stat
, mount_crypt_stat
);
986 crypt_stat
->flags
|= (ECRYPTFS_ENCRYPTED
| ECRYPTFS_KEY_VALID
);
987 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat
,
989 rc
= ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat
,
992 printk(KERN_ERR
"Error attempting to copy mount-wide key sigs "
993 "to the inode key sigs; rc = [%d]\n", rc
);
997 strlen(mount_crypt_stat
->global_default_cipher_name
);
998 memcpy(crypt_stat
->cipher
,
999 mount_crypt_stat
->global_default_cipher_name
,
1001 crypt_stat
->cipher
[cipher_name_len
] = '\0';
1002 crypt_stat
->key_size
=
1003 mount_crypt_stat
->global_default_cipher_key_size
;
1004 ecryptfs_generate_new_key(crypt_stat
);
1005 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1007 ecryptfs_printk(KERN_ERR
, "Error initializing cryptographic "
1008 "context for cipher [%s]: rc = [%d]\n",
1009 crypt_stat
->cipher
, rc
);
1015 * contains_ecryptfs_marker - check for the ecryptfs marker
1016 * @data: The data block in which to check
1018 * Returns one if marker found; zero if not found
1020 static int contains_ecryptfs_marker(char *data
)
1024 memcpy(&m_1
, data
, 4);
1025 m_1
= be32_to_cpu(m_1
);
1026 memcpy(&m_2
, (data
+ 4), 4);
1027 m_2
= be32_to_cpu(m_2
);
1028 if ((m_1
^ MAGIC_ECRYPTFS_MARKER
) == m_2
)
1030 ecryptfs_printk(KERN_DEBUG
, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1031 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1
, m_2
,
1032 MAGIC_ECRYPTFS_MARKER
);
1033 ecryptfs_printk(KERN_DEBUG
, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1034 "[0x%.8x]\n", (m_1
^ MAGIC_ECRYPTFS_MARKER
));
1038 struct ecryptfs_flag_map_elem
{
1043 /* Add support for additional flags by adding elements here. */
1044 static struct ecryptfs_flag_map_elem ecryptfs_flag_map
[] = {
1045 {0x00000001, ECRYPTFS_ENABLE_HMAC
},
1046 {0x00000002, ECRYPTFS_ENCRYPTED
},
1047 {0x00000004, ECRYPTFS_METADATA_IN_XATTR
}
1051 * ecryptfs_process_flags
1052 * @crypt_stat: The cryptographic context
1053 * @page_virt: Source data to be parsed
1054 * @bytes_read: Updated with the number of bytes read
1056 * Returns zero on success; non-zero if the flag set is invalid
1058 static int ecryptfs_process_flags(struct ecryptfs_crypt_stat
*crypt_stat
,
1059 char *page_virt
, int *bytes_read
)
1065 memcpy(&flags
, page_virt
, 4);
1066 flags
= be32_to_cpu(flags
);
1067 for (i
= 0; i
< ((sizeof(ecryptfs_flag_map
)
1068 / sizeof(struct ecryptfs_flag_map_elem
))); i
++)
1069 if (flags
& ecryptfs_flag_map
[i
].file_flag
) {
1070 crypt_stat
->flags
|= ecryptfs_flag_map
[i
].local_flag
;
1072 crypt_stat
->flags
&= ~(ecryptfs_flag_map
[i
].local_flag
);
1073 /* Version is in top 8 bits of the 32-bit flag vector */
1074 crypt_stat
->file_version
= ((flags
>> 24) & 0xFF);
1080 * write_ecryptfs_marker
1081 * @page_virt: The pointer to in a page to begin writing the marker
1082 * @written: Number of bytes written
1084 * Marker = 0x3c81b7f5
1086 static void write_ecryptfs_marker(char *page_virt
, size_t *written
)
1090 get_random_bytes(&m_1
, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
/ 2));
1091 m_2
= (m_1
^ MAGIC_ECRYPTFS_MARKER
);
1092 m_1
= cpu_to_be32(m_1
);
1093 memcpy(page_virt
, &m_1
, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
/ 2));
1094 m_2
= cpu_to_be32(m_2
);
1095 memcpy(page_virt
+ (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
/ 2), &m_2
,
1096 (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
/ 2));
1097 (*written
) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
;
1101 write_ecryptfs_flags(char *page_virt
, struct ecryptfs_crypt_stat
*crypt_stat
,
1107 for (i
= 0; i
< ((sizeof(ecryptfs_flag_map
)
1108 / sizeof(struct ecryptfs_flag_map_elem
))); i
++)
1109 if (crypt_stat
->flags
& ecryptfs_flag_map
[i
].local_flag
)
1110 flags
|= ecryptfs_flag_map
[i
].file_flag
;
1111 /* Version is in top 8 bits of the 32-bit flag vector */
1112 flags
|= ((((u8
)crypt_stat
->file_version
) << 24) & 0xFF000000);
1113 flags
= cpu_to_be32(flags
);
1114 memcpy(page_virt
, &flags
, 4);
1118 struct ecryptfs_cipher_code_str_map_elem
{
1119 char cipher_str
[16];
1123 /* Add support for additional ciphers by adding elements here. The
1124 * cipher_code is whatever OpenPGP applicatoins use to identify the
1125 * ciphers. List in order of probability. */
1126 static struct ecryptfs_cipher_code_str_map_elem
1127 ecryptfs_cipher_code_str_map
[] = {
1128 {"aes",RFC2440_CIPHER_AES_128
},
1129 {"blowfish", RFC2440_CIPHER_BLOWFISH
},
1130 {"des3_ede", RFC2440_CIPHER_DES3_EDE
},
1131 {"cast5", RFC2440_CIPHER_CAST_5
},
1132 {"twofish", RFC2440_CIPHER_TWOFISH
},
1133 {"cast6", RFC2440_CIPHER_CAST_6
},
1134 {"aes", RFC2440_CIPHER_AES_192
},
1135 {"aes", RFC2440_CIPHER_AES_256
}
1139 * ecryptfs_code_for_cipher_string
1140 * @crypt_stat: The cryptographic context
1142 * Returns zero on no match, or the cipher code on match
1144 u16
ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat
*crypt_stat
)
1148 struct ecryptfs_cipher_code_str_map_elem
*map
=
1149 ecryptfs_cipher_code_str_map
;
1151 if (strcmp(crypt_stat
->cipher
, "aes") == 0) {
1152 switch (crypt_stat
->key_size
) {
1154 code
= RFC2440_CIPHER_AES_128
;
1157 code
= RFC2440_CIPHER_AES_192
;
1160 code
= RFC2440_CIPHER_AES_256
;
1163 for (i
= 0; i
< ARRAY_SIZE(ecryptfs_cipher_code_str_map
); i
++)
1164 if (strcmp(crypt_stat
->cipher
, map
[i
].cipher_str
) == 0){
1165 code
= map
[i
].cipher_code
;
1173 * ecryptfs_cipher_code_to_string
1174 * @str: Destination to write out the cipher name
1175 * @cipher_code: The code to convert to cipher name string
1177 * Returns zero on success
1179 int ecryptfs_cipher_code_to_string(char *str
, u16 cipher_code
)
1185 for (i
= 0; i
< ARRAY_SIZE(ecryptfs_cipher_code_str_map
); i
++)
1186 if (cipher_code
== ecryptfs_cipher_code_str_map
[i
].cipher_code
)
1187 strcpy(str
, ecryptfs_cipher_code_str_map
[i
].cipher_str
);
1188 if (str
[0] == '\0') {
1189 ecryptfs_printk(KERN_WARNING
, "Cipher code not recognized: "
1190 "[%d]\n", cipher_code
);
1196 int ecryptfs_read_and_validate_header_region(char *data
,
1197 struct inode
*ecryptfs_inode
)
1199 struct ecryptfs_crypt_stat
*crypt_stat
=
1200 &(ecryptfs_inode_to_private(ecryptfs_inode
)->crypt_stat
);
1203 rc
= ecryptfs_read_lower(data
, 0, crypt_stat
->extent_size
,
1206 printk(KERN_ERR
"%s: Error reading header region; rc = [%d]\n",
1210 if (!contains_ecryptfs_marker(data
+ ECRYPTFS_FILE_SIZE_BYTES
)) {
1212 ecryptfs_printk(KERN_DEBUG
, "Valid marker not found\n");
1219 ecryptfs_write_header_metadata(char *virt
,
1220 struct ecryptfs_crypt_stat
*crypt_stat
,
1223 u32 header_extent_size
;
1224 u16 num_header_extents_at_front
;
1226 header_extent_size
= (u32
)crypt_stat
->extent_size
;
1227 num_header_extents_at_front
=
1228 (u16
)crypt_stat
->num_header_extents_at_front
;
1229 header_extent_size
= cpu_to_be32(header_extent_size
);
1230 memcpy(virt
, &header_extent_size
, 4);
1232 num_header_extents_at_front
= cpu_to_be16(num_header_extents_at_front
);
1233 memcpy(virt
, &num_header_extents_at_front
, 2);
1237 struct kmem_cache
*ecryptfs_header_cache_0
;
1238 struct kmem_cache
*ecryptfs_header_cache_1
;
1239 struct kmem_cache
*ecryptfs_header_cache_2
;
1242 * ecryptfs_write_headers_virt
1243 * @page_virt: The virtual address to write the headers to
1244 * @size: Set to the number of bytes written by this function
1245 * @crypt_stat: The cryptographic context
1246 * @ecryptfs_dentry: The eCryptfs dentry
1251 * Octets 0-7: Unencrypted file size (big-endian)
1252 * Octets 8-15: eCryptfs special marker
1253 * Octets 16-19: Flags
1254 * Octet 16: File format version number (between 0 and 255)
1255 * Octets 17-18: Reserved
1256 * Octet 19: Bit 1 (lsb): Reserved
1258 * Bits 3-8: Reserved
1259 * Octets 20-23: Header extent size (big-endian)
1260 * Octets 24-25: Number of header extents at front of file
1262 * Octet 26: Begin RFC 2440 authentication token packet set
1264 * Lower data (CBC encrypted)
1266 * Lower data (CBC encrypted)
1269 * Returns zero on success
1271 static int ecryptfs_write_headers_virt(char *page_virt
, size_t *size
,
1272 struct ecryptfs_crypt_stat
*crypt_stat
,
1273 struct dentry
*ecryptfs_dentry
)
1279 offset
= ECRYPTFS_FILE_SIZE_BYTES
;
1280 write_ecryptfs_marker((page_virt
+ offset
), &written
);
1282 write_ecryptfs_flags((page_virt
+ offset
), crypt_stat
, &written
);
1284 ecryptfs_write_header_metadata((page_virt
+ offset
), crypt_stat
,
1287 rc
= ecryptfs_generate_key_packet_set((page_virt
+ offset
), crypt_stat
,
1288 ecryptfs_dentry
, &written
,
1289 PAGE_CACHE_SIZE
- offset
);
1291 ecryptfs_printk(KERN_WARNING
, "Error generating key packet "
1292 "set; rc = [%d]\n", rc
);
1301 ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat
*crypt_stat
,
1302 struct dentry
*ecryptfs_dentry
,
1305 int current_header_page
;
1309 rc
= ecryptfs_write_lower(ecryptfs_dentry
->d_inode
, page_virt
,
1310 0, PAGE_CACHE_SIZE
);
1312 printk(KERN_ERR
"%s: Error attempting to write header "
1313 "information to lower file; rc = [%d]\n", __FUNCTION__
,
1317 header_pages
= ((crypt_stat
->extent_size
1318 * crypt_stat
->num_header_extents_at_front
)
1320 memset(page_virt
, 0, PAGE_CACHE_SIZE
);
1321 current_header_page
= 1;
1322 while (current_header_page
< header_pages
) {
1325 offset
= (((loff_t
)current_header_page
) << PAGE_CACHE_SHIFT
);
1326 if ((rc
= ecryptfs_write_lower(ecryptfs_dentry
->d_inode
,
1328 PAGE_CACHE_SIZE
))) {
1329 printk(KERN_ERR
"%s: Error attempting to write header "
1330 "information to lower file; rc = [%d]\n",
1334 current_header_page
++;
1341 ecryptfs_write_metadata_to_xattr(struct dentry
*ecryptfs_dentry
,
1342 struct ecryptfs_crypt_stat
*crypt_stat
,
1343 char *page_virt
, size_t size
)
1347 rc
= ecryptfs_setxattr(ecryptfs_dentry
, ECRYPTFS_XATTR_NAME
, page_virt
,
1353 * ecryptfs_write_metadata
1354 * @ecryptfs_dentry: The eCryptfs dentry
1356 * Write the file headers out. This will likely involve a userspace
1357 * callout, in which the session key is encrypted with one or more
1358 * public keys and/or the passphrase necessary to do the encryption is
1359 * retrieved via a prompt. Exactly what happens at this point should
1360 * be policy-dependent.
1362 * TODO: Support header information spanning multiple pages
1364 * Returns zero on success; non-zero on error
1366 int ecryptfs_write_metadata(struct dentry
*ecryptfs_dentry
)
1368 struct ecryptfs_crypt_stat
*crypt_stat
=
1369 &ecryptfs_inode_to_private(ecryptfs_dentry
->d_inode
)->crypt_stat
;
1374 if (likely(crypt_stat
->flags
& ECRYPTFS_ENCRYPTED
)) {
1375 if (!(crypt_stat
->flags
& ECRYPTFS_KEY_VALID
)) {
1376 printk(KERN_ERR
"Key is invalid; bailing out\n");
1382 ecryptfs_printk(KERN_WARNING
,
1383 "Called with crypt_stat->encrypted == 0\n");
1386 /* Released in this function */
1387 page_virt
= kmem_cache_zalloc(ecryptfs_header_cache_0
, GFP_USER
);
1389 ecryptfs_printk(KERN_ERR
, "Out of memory\n");
1393 rc
= ecryptfs_write_headers_virt(page_virt
, &size
, crypt_stat
,
1396 ecryptfs_printk(KERN_ERR
, "Error whilst writing headers\n");
1397 memset(page_virt
, 0, PAGE_CACHE_SIZE
);
1400 if (crypt_stat
->flags
& ECRYPTFS_METADATA_IN_XATTR
)
1401 rc
= ecryptfs_write_metadata_to_xattr(ecryptfs_dentry
,
1402 crypt_stat
, page_virt
,
1405 rc
= ecryptfs_write_metadata_to_contents(crypt_stat
,
1409 printk(KERN_ERR
"Error writing metadata out to lower file; "
1414 kmem_cache_free(ecryptfs_header_cache_0
, page_virt
);
1419 #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1420 #define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1421 static int parse_header_metadata(struct ecryptfs_crypt_stat
*crypt_stat
,
1422 char *virt
, int *bytes_read
,
1423 int validate_header_size
)
1426 u32 header_extent_size
;
1427 u16 num_header_extents_at_front
;
1429 memcpy(&header_extent_size
, virt
, 4);
1430 header_extent_size
= be32_to_cpu(header_extent_size
);
1432 memcpy(&num_header_extents_at_front
, virt
, 2);
1433 num_header_extents_at_front
= be16_to_cpu(num_header_extents_at_front
);
1434 crypt_stat
->num_header_extents_at_front
=
1435 (int)num_header_extents_at_front
;
1436 (*bytes_read
) = (sizeof(u32
) + sizeof(u16
));
1437 if ((validate_header_size
== ECRYPTFS_VALIDATE_HEADER_SIZE
)
1438 && ((crypt_stat
->extent_size
1439 * crypt_stat
->num_header_extents_at_front
)
1440 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
)) {
1442 printk(KERN_WARNING
"Invalid number of header extents: [%zd]\n",
1443 crypt_stat
->num_header_extents_at_front
);
1449 * set_default_header_data
1450 * @crypt_stat: The cryptographic context
1452 * For version 0 file format; this function is only for backwards
1453 * compatibility for files created with the prior versions of
1456 static void set_default_header_data(struct ecryptfs_crypt_stat
*crypt_stat
)
1458 crypt_stat
->num_header_extents_at_front
= 2;
1462 * ecryptfs_read_headers_virt
1463 * @page_virt: The virtual address into which to read the headers
1464 * @crypt_stat: The cryptographic context
1465 * @ecryptfs_dentry: The eCryptfs dentry
1466 * @validate_header_size: Whether to validate the header size while reading
1468 * Read/parse the header data. The header format is detailed in the
1469 * comment block for the ecryptfs_write_headers_virt() function.
1471 * Returns zero on success
1473 static int ecryptfs_read_headers_virt(char *page_virt
,
1474 struct ecryptfs_crypt_stat
*crypt_stat
,
1475 struct dentry
*ecryptfs_dentry
,
1476 int validate_header_size
)
1482 ecryptfs_set_default_sizes(crypt_stat
);
1483 crypt_stat
->mount_crypt_stat
= &ecryptfs_superblock_to_private(
1484 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
1485 offset
= ECRYPTFS_FILE_SIZE_BYTES
;
1486 rc
= contains_ecryptfs_marker(page_virt
+ offset
);
1491 offset
+= MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
;
1492 rc
= ecryptfs_process_flags(crypt_stat
, (page_virt
+ offset
),
1495 ecryptfs_printk(KERN_WARNING
, "Error processing flags\n");
1498 if (crypt_stat
->file_version
> ECRYPTFS_SUPPORTED_FILE_VERSION
) {
1499 ecryptfs_printk(KERN_WARNING
, "File version is [%d]; only "
1500 "file version [%d] is supported by this "
1501 "version of eCryptfs\n",
1502 crypt_stat
->file_version
,
1503 ECRYPTFS_SUPPORTED_FILE_VERSION
);
1507 offset
+= bytes_read
;
1508 if (crypt_stat
->file_version
>= 1) {
1509 rc
= parse_header_metadata(crypt_stat
, (page_virt
+ offset
),
1510 &bytes_read
, validate_header_size
);
1512 ecryptfs_printk(KERN_WARNING
, "Error reading header "
1513 "metadata; rc = [%d]\n", rc
);
1515 offset
+= bytes_read
;
1517 set_default_header_data(crypt_stat
);
1518 rc
= ecryptfs_parse_packet_set(crypt_stat
, (page_virt
+ offset
),
1525 * ecryptfs_read_xattr_region
1526 * @page_virt: The vitual address into which to read the xattr data
1527 * @ecryptfs_inode: The eCryptfs inode
1529 * Attempts to read the crypto metadata from the extended attribute
1530 * region of the lower file.
1532 * Returns zero on success; non-zero on error
1534 int ecryptfs_read_xattr_region(char *page_virt
, struct inode
*ecryptfs_inode
)
1536 struct dentry
*lower_dentry
=
1537 ecryptfs_inode_to_private(ecryptfs_inode
)->lower_file
->f_dentry
;
1541 size
= ecryptfs_getxattr_lower(lower_dentry
, ECRYPTFS_XATTR_NAME
,
1542 page_virt
, ECRYPTFS_DEFAULT_EXTENT_SIZE
);
1544 printk(KERN_ERR
"Error attempting to read the [%s] "
1545 "xattr from the lower file; return value = [%zd]\n",
1546 ECRYPTFS_XATTR_NAME
, size
);
1554 int ecryptfs_read_and_validate_xattr_region(char *page_virt
,
1555 struct dentry
*ecryptfs_dentry
)
1559 rc
= ecryptfs_read_xattr_region(page_virt
, ecryptfs_dentry
->d_inode
);
1562 if (!contains_ecryptfs_marker(page_virt
+ ECRYPTFS_FILE_SIZE_BYTES
)) {
1563 printk(KERN_WARNING
"Valid data found in [%s] xattr, but "
1564 "the marker is invalid\n", ECRYPTFS_XATTR_NAME
);
1572 * ecryptfs_read_metadata
1574 * Common entry point for reading file metadata. From here, we could
1575 * retrieve the header information from the header region of the file,
1576 * the xattr region of the file, or some other repostory that is
1577 * stored separately from the file itself. The current implementation
1578 * supports retrieving the metadata information from the file contents
1579 * and from the xattr region.
1581 * Returns zero if valid headers found and parsed; non-zero otherwise
1583 int ecryptfs_read_metadata(struct dentry
*ecryptfs_dentry
)
1586 char *page_virt
= NULL
;
1587 struct inode
*ecryptfs_inode
= ecryptfs_dentry
->d_inode
;
1588 struct ecryptfs_crypt_stat
*crypt_stat
=
1589 &ecryptfs_inode_to_private(ecryptfs_inode
)->crypt_stat
;
1590 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1591 &ecryptfs_superblock_to_private(
1592 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
1594 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat
,
1596 /* Read the first page from the underlying file */
1597 page_virt
= kmem_cache_alloc(ecryptfs_header_cache_1
, GFP_USER
);
1600 printk(KERN_ERR
"%s: Unable to allocate page_virt\n",
1604 rc
= ecryptfs_read_lower(page_virt
, 0, crypt_stat
->extent_size
,
1607 rc
= ecryptfs_read_headers_virt(page_virt
, crypt_stat
,
1609 ECRYPTFS_VALIDATE_HEADER_SIZE
);
1611 rc
= ecryptfs_read_xattr_region(page_virt
, ecryptfs_inode
);
1613 printk(KERN_DEBUG
"Valid eCryptfs headers not found in "
1614 "file header region or xattr region\n");
1618 rc
= ecryptfs_read_headers_virt(page_virt
, crypt_stat
,
1620 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE
);
1622 printk(KERN_DEBUG
"Valid eCryptfs headers not found in "
1623 "file xattr region either\n");
1626 if (crypt_stat
->mount_crypt_stat
->flags
1627 & ECRYPTFS_XATTR_METADATA_ENABLED
) {
1628 crypt_stat
->flags
|= ECRYPTFS_METADATA_IN_XATTR
;
1630 printk(KERN_WARNING
"Attempt to access file with "
1631 "crypto metadata only in the extended attribute "
1632 "region, but eCryptfs was mounted without "
1633 "xattr support enabled. eCryptfs will not treat "
1634 "this like an encrypted file.\n");
1640 memset(page_virt
, 0, PAGE_CACHE_SIZE
);
1641 kmem_cache_free(ecryptfs_header_cache_1
, page_virt
);
1647 * ecryptfs_encode_filename - converts a plaintext file name to cipher text
1648 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
1649 * @name: The plaintext name
1650 * @length: The length of the plaintext
1651 * @encoded_name: The encypted name
1653 * Encrypts and encodes a filename into something that constitutes a
1654 * valid filename for a filesystem, with printable characters.
1656 * We assume that we have a properly initialized crypto context,
1657 * pointed to by crypt_stat->tfm.
1659 * TODO: Implement filename decoding and decryption here, in place of
1660 * memcpy. We are keeping the framework around for now to (1)
1661 * facilitate testing of the components needed to implement filename
1662 * encryption and (2) to provide a code base from which other
1663 * developers in the community can easily implement this feature.
1665 * Returns the length of encoded filename; negative if error
1668 ecryptfs_encode_filename(struct ecryptfs_crypt_stat
*crypt_stat
,
1669 const char *name
, int length
, char **encoded_name
)
1673 (*encoded_name
) = kmalloc(length
+ 2, GFP_KERNEL
);
1674 if (!(*encoded_name
)) {
1678 /* TODO: Filename encryption is a scheduled feature for a
1679 * future version of eCryptfs. This function is here only for
1680 * the purpose of providing a framework for other developers
1681 * to easily implement filename encryption. Hint: Replace this
1682 * memcpy() with a call to encrypt and encode the
1683 * filename, the set the length accordingly. */
1684 memcpy((void *)(*encoded_name
), (void *)name
, length
);
1685 (*encoded_name
)[length
] = '\0';
1692 * ecryptfs_decode_filename - converts the cipher text name to plaintext
1693 * @crypt_stat: The crypt_stat struct associated with the file
1694 * @name: The filename in cipher text
1695 * @length: The length of the cipher text name
1696 * @decrypted_name: The plaintext name
1698 * Decodes and decrypts the filename.
1700 * We assume that we have a properly initialized crypto context,
1701 * pointed to by crypt_stat->tfm.
1703 * TODO: Implement filename decoding and decryption here, in place of
1704 * memcpy. We are keeping the framework around for now to (1)
1705 * facilitate testing of the components needed to implement filename
1706 * encryption and (2) to provide a code base from which other
1707 * developers in the community can easily implement this feature.
1709 * Returns the length of decoded filename; negative if error
1712 ecryptfs_decode_filename(struct ecryptfs_crypt_stat
*crypt_stat
,
1713 const char *name
, int length
, char **decrypted_name
)
1717 (*decrypted_name
) = kmalloc(length
+ 2, GFP_KERNEL
);
1718 if (!(*decrypted_name
)) {
1722 /* TODO: Filename encryption is a scheduled feature for a
1723 * future version of eCryptfs. This function is here only for
1724 * the purpose of providing a framework for other developers
1725 * to easily implement filename encryption. Hint: Replace this
1726 * memcpy() with a call to decode and decrypt the
1727 * filename, the set the length accordingly. */
1728 memcpy((void *)(*decrypted_name
), (void *)name
, length
);
1729 (*decrypted_name
)[length
+ 1] = '\0'; /* Only for convenience
1730 * in printing out the
1739 * ecryptfs_process_key_cipher - Perform key cipher initialization.
1740 * @key_tfm: Crypto context for key material, set by this function
1741 * @cipher_name: Name of the cipher
1742 * @key_size: Size of the key in bytes
1744 * Returns zero on success. Any crypto_tfm structs allocated here
1745 * should be released by other functions, such as on a superblock put
1746 * event, regardless of whether this function succeeds for fails.
1749 ecryptfs_process_key_cipher(struct crypto_blkcipher
**key_tfm
,
1750 char *cipher_name
, size_t *key_size
)
1752 char dummy_key
[ECRYPTFS_MAX_KEY_BYTES
];
1753 char *full_alg_name
;
1757 if (*key_size
> ECRYPTFS_MAX_KEY_BYTES
) {
1759 printk(KERN_ERR
"Requested key size is [%Zd] bytes; maximum "
1760 "allowable is [%d]\n", *key_size
, ECRYPTFS_MAX_KEY_BYTES
);
1763 rc
= ecryptfs_crypto_api_algify_cipher_name(&full_alg_name
, cipher_name
,
1767 *key_tfm
= crypto_alloc_blkcipher(full_alg_name
, 0, CRYPTO_ALG_ASYNC
);
1768 kfree(full_alg_name
);
1769 if (IS_ERR(*key_tfm
)) {
1770 rc
= PTR_ERR(*key_tfm
);
1771 printk(KERN_ERR
"Unable to allocate crypto cipher with name "
1772 "[%s]; rc = [%d]\n", cipher_name
, rc
);
1775 crypto_blkcipher_set_flags(*key_tfm
, CRYPTO_TFM_REQ_WEAK_KEY
);
1776 if (*key_size
== 0) {
1777 struct blkcipher_alg
*alg
= crypto_blkcipher_alg(*key_tfm
);
1779 *key_size
= alg
->max_keysize
;
1781 get_random_bytes(dummy_key
, *key_size
);
1782 rc
= crypto_blkcipher_setkey(*key_tfm
, dummy_key
, *key_size
);
1784 printk(KERN_ERR
"Error attempting to set key of size [%Zd] for "
1785 "cipher [%s]; rc = [%d]\n", *key_size
, cipher_name
, rc
);
1793 struct kmem_cache
*ecryptfs_key_tfm_cache
;
1794 struct list_head key_tfm_list
;
1795 struct mutex key_tfm_list_mutex
;
1797 int ecryptfs_init_crypto(void)
1799 mutex_init(&key_tfm_list_mutex
);
1800 INIT_LIST_HEAD(&key_tfm_list
);
1804 int ecryptfs_destroy_crypto(void)
1806 struct ecryptfs_key_tfm
*key_tfm
, *key_tfm_tmp
;
1808 mutex_lock(&key_tfm_list_mutex
);
1809 list_for_each_entry_safe(key_tfm
, key_tfm_tmp
, &key_tfm_list
,
1811 list_del(&key_tfm
->key_tfm_list
);
1812 if (key_tfm
->key_tfm
)
1813 crypto_free_blkcipher(key_tfm
->key_tfm
);
1814 kmem_cache_free(ecryptfs_key_tfm_cache
, key_tfm
);
1816 mutex_unlock(&key_tfm_list_mutex
);
1821 ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm
**key_tfm
, char *cipher_name
,
1824 struct ecryptfs_key_tfm
*tmp_tfm
;
1827 tmp_tfm
= kmem_cache_alloc(ecryptfs_key_tfm_cache
, GFP_KERNEL
);
1828 if (key_tfm
!= NULL
)
1829 (*key_tfm
) = tmp_tfm
;
1832 printk(KERN_ERR
"Error attempting to allocate from "
1833 "ecryptfs_key_tfm_cache\n");
1836 mutex_init(&tmp_tfm
->key_tfm_mutex
);
1837 strncpy(tmp_tfm
->cipher_name
, cipher_name
,
1838 ECRYPTFS_MAX_CIPHER_NAME_SIZE
);
1839 tmp_tfm
->key_size
= key_size
;
1840 rc
= ecryptfs_process_key_cipher(&tmp_tfm
->key_tfm
,
1841 tmp_tfm
->cipher_name
,
1842 &tmp_tfm
->key_size
);
1844 printk(KERN_ERR
"Error attempting to initialize key TFM "
1845 "cipher with name = [%s]; rc = [%d]\n",
1846 tmp_tfm
->cipher_name
, rc
);
1847 kmem_cache_free(ecryptfs_key_tfm_cache
, tmp_tfm
);
1848 if (key_tfm
!= NULL
)
1852 mutex_lock(&key_tfm_list_mutex
);
1853 list_add(&tmp_tfm
->key_tfm_list
, &key_tfm_list
);
1854 mutex_unlock(&key_tfm_list_mutex
);
1859 int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher
**tfm
,
1860 struct mutex
**tfm_mutex
,
1863 struct ecryptfs_key_tfm
*key_tfm
;
1867 (*tfm_mutex
) = NULL
;
1868 mutex_lock(&key_tfm_list_mutex
);
1869 list_for_each_entry(key_tfm
, &key_tfm_list
, key_tfm_list
) {
1870 if (strcmp(key_tfm
->cipher_name
, cipher_name
) == 0) {
1871 (*tfm
) = key_tfm
->key_tfm
;
1872 (*tfm_mutex
) = &key_tfm
->key_tfm_mutex
;
1873 mutex_unlock(&key_tfm_list_mutex
);
1877 mutex_unlock(&key_tfm_list_mutex
);
1878 rc
= ecryptfs_add_new_key_tfm(&key_tfm
, cipher_name
, 0);
1880 printk(KERN_ERR
"Error adding new key_tfm to list; rc = [%d]\n",
1884 (*tfm
) = key_tfm
->key_tfm
;
1885 (*tfm_mutex
) = &key_tfm
->key_tfm_mutex
;