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
);
286 sg_set_page(&sg
[i
], pg
);
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__
,
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");
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]"
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
);
646 kfree(enc_extent_virt
);
651 * decrypt_scatterlist
652 * @crypt_stat: Cryptographic context
653 * @dest_sg: The destination scatterlist to decrypt into
654 * @src_sg: The source scatterlist to decrypt from
655 * @size: The number of bytes to decrypt
656 * @iv: The initialization vector to use for the decryption
658 * Returns the number of bytes decrypted; negative value on error
660 static int decrypt_scatterlist(struct ecryptfs_crypt_stat
*crypt_stat
,
661 struct scatterlist
*dest_sg
,
662 struct scatterlist
*src_sg
, int size
,
665 struct blkcipher_desc desc
= {
666 .tfm
= crypt_stat
->tfm
,
668 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
672 /* Consider doing this once, when the file is opened */
673 mutex_lock(&crypt_stat
->cs_tfm_mutex
);
674 rc
= crypto_blkcipher_setkey(crypt_stat
->tfm
, crypt_stat
->key
,
675 crypt_stat
->key_size
);
677 ecryptfs_printk(KERN_ERR
, "Error setting key; rc = [%d]\n",
679 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
683 ecryptfs_printk(KERN_DEBUG
, "Decrypting [%d] bytes.\n", size
);
684 rc
= crypto_blkcipher_decrypt_iv(&desc
, dest_sg
, src_sg
, size
);
685 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
687 ecryptfs_printk(KERN_ERR
, "Error decrypting; rc = [%d]\n",
697 * ecryptfs_encrypt_page_offset
698 * @crypt_stat: The cryptographic context
699 * @dst_page: The page to encrypt into
700 * @dst_offset: The offset in the page to encrypt into
701 * @src_page: The page to encrypt from
702 * @src_offset: The offset in the page to encrypt from
703 * @size: The number of bytes to encrypt
704 * @iv: The initialization vector to use for the encryption
706 * Returns the number of bytes encrypted
709 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat
*crypt_stat
,
710 struct page
*dst_page
, int dst_offset
,
711 struct page
*src_page
, int src_offset
, int size
,
714 struct scatterlist src_sg
, dst_sg
;
716 sg_init_table(&src_sg
, 1);
717 sg_init_table(&dst_sg
, 1);
719 sg_set_page(&src_sg
, src_page
);
720 src_sg
.offset
= src_offset
;
721 src_sg
.length
= size
;
722 sg_set_page(&dst_sg
, dst_page
);
723 dst_sg
.offset
= dst_offset
;
724 dst_sg
.length
= size
;
725 return encrypt_scatterlist(crypt_stat
, &dst_sg
, &src_sg
, size
, iv
);
729 * ecryptfs_decrypt_page_offset
730 * @crypt_stat: The cryptographic context
731 * @dst_page: The page to decrypt into
732 * @dst_offset: The offset in the page to decrypt into
733 * @src_page: The page to decrypt from
734 * @src_offset: The offset in the page to decrypt from
735 * @size: The number of bytes to decrypt
736 * @iv: The initialization vector to use for the decryption
738 * Returns the number of bytes decrypted
741 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat
*crypt_stat
,
742 struct page
*dst_page
, int dst_offset
,
743 struct page
*src_page
, int src_offset
, int size
,
746 struct scatterlist src_sg
, dst_sg
;
748 sg_init_table(&src_sg
, 1);
749 sg_init_table(&dst_sg
, 1);
751 sg_set_page(&src_sg
, src_page
);
752 src_sg
.offset
= src_offset
;
753 src_sg
.length
= size
;
754 sg_set_page(&dst_sg
, dst_page
);
755 dst_sg
.offset
= dst_offset
;
756 dst_sg
.length
= size
;
757 return decrypt_scatterlist(crypt_stat
, &dst_sg
, &src_sg
, size
, iv
);
760 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
763 * ecryptfs_init_crypt_ctx
764 * @crypt_stat: Uninitilized crypt stats structure
766 * Initialize the crypto context.
768 * TODO: Performance: Keep a cache of initialized cipher contexts;
769 * only init if needed
771 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat
*crypt_stat
)
776 if (!crypt_stat
->cipher
) {
777 ecryptfs_printk(KERN_ERR
, "No cipher specified\n");
780 ecryptfs_printk(KERN_DEBUG
,
781 "Initializing cipher [%s]; strlen = [%d]; "
782 "key_size_bits = [%d]\n",
783 crypt_stat
->cipher
, (int)strlen(crypt_stat
->cipher
),
784 crypt_stat
->key_size
<< 3);
785 if (crypt_stat
->tfm
) {
789 mutex_lock(&crypt_stat
->cs_tfm_mutex
);
790 rc
= ecryptfs_crypto_api_algify_cipher_name(&full_alg_name
,
791 crypt_stat
->cipher
, "cbc");
794 crypt_stat
->tfm
= crypto_alloc_blkcipher(full_alg_name
, 0,
796 kfree(full_alg_name
);
797 if (IS_ERR(crypt_stat
->tfm
)) {
798 rc
= PTR_ERR(crypt_stat
->tfm
);
799 ecryptfs_printk(KERN_ERR
, "cryptfs: init_crypt_ctx(): "
800 "Error initializing cipher [%s]\n",
802 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
805 crypto_blkcipher_set_flags(crypt_stat
->tfm
, CRYPTO_TFM_REQ_WEAK_KEY
);
806 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
812 static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat
*crypt_stat
)
816 crypt_stat
->extent_mask
= 0xFFFFFFFF;
817 crypt_stat
->extent_shift
= 0;
818 if (crypt_stat
->extent_size
== 0)
820 extent_size_tmp
= crypt_stat
->extent_size
;
821 while ((extent_size_tmp
& 0x01) == 0) {
822 extent_size_tmp
>>= 1;
823 crypt_stat
->extent_mask
<<= 1;
824 crypt_stat
->extent_shift
++;
828 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat
*crypt_stat
)
830 /* Default values; may be overwritten as we are parsing the
832 crypt_stat
->extent_size
= ECRYPTFS_DEFAULT_EXTENT_SIZE
;
833 set_extent_mask_and_shift(crypt_stat
);
834 crypt_stat
->iv_bytes
= ECRYPTFS_DEFAULT_IV_BYTES
;
835 if (crypt_stat
->flags
& ECRYPTFS_METADATA_IN_XATTR
)
836 crypt_stat
->num_header_extents_at_front
= 0;
838 if (PAGE_CACHE_SIZE
<= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
)
839 crypt_stat
->num_header_extents_at_front
=
840 (ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
841 / crypt_stat
->extent_size
);
843 crypt_stat
->num_header_extents_at_front
=
844 (PAGE_CACHE_SIZE
/ crypt_stat
->extent_size
);
849 * ecryptfs_compute_root_iv
852 * On error, sets the root IV to all 0's.
854 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat
*crypt_stat
)
857 char dst
[MD5_DIGEST_SIZE
];
859 BUG_ON(crypt_stat
->iv_bytes
> MD5_DIGEST_SIZE
);
860 BUG_ON(crypt_stat
->iv_bytes
<= 0);
861 if (!(crypt_stat
->flags
& ECRYPTFS_KEY_VALID
)) {
863 ecryptfs_printk(KERN_WARNING
, "Session key not valid; "
864 "cannot generate root IV\n");
867 rc
= ecryptfs_calculate_md5(dst
, crypt_stat
, crypt_stat
->key
,
868 crypt_stat
->key_size
);
870 ecryptfs_printk(KERN_WARNING
, "Error attempting to compute "
871 "MD5 while generating root IV\n");
874 memcpy(crypt_stat
->root_iv
, dst
, crypt_stat
->iv_bytes
);
877 memset(crypt_stat
->root_iv
, 0, crypt_stat
->iv_bytes
);
878 crypt_stat
->flags
|= ECRYPTFS_SECURITY_WARNING
;
883 static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat
*crypt_stat
)
885 get_random_bytes(crypt_stat
->key
, crypt_stat
->key_size
);
886 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
887 ecryptfs_compute_root_iv(crypt_stat
);
888 if (unlikely(ecryptfs_verbosity
> 0)) {
889 ecryptfs_printk(KERN_DEBUG
, "Generated new session key:\n");
890 ecryptfs_dump_hex(crypt_stat
->key
,
891 crypt_stat
->key_size
);
896 * ecryptfs_copy_mount_wide_flags_to_inode_flags
897 * @crypt_stat: The inode's cryptographic context
898 * @mount_crypt_stat: The mount point's cryptographic context
900 * This function propagates the mount-wide flags to individual inode
903 static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
904 struct ecryptfs_crypt_stat
*crypt_stat
,
905 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
)
907 if (mount_crypt_stat
->flags
& ECRYPTFS_XATTR_METADATA_ENABLED
)
908 crypt_stat
->flags
|= ECRYPTFS_METADATA_IN_XATTR
;
909 if (mount_crypt_stat
->flags
& ECRYPTFS_ENCRYPTED_VIEW_ENABLED
)
910 crypt_stat
->flags
|= ECRYPTFS_VIEW_AS_ENCRYPTED
;
913 static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
914 struct ecryptfs_crypt_stat
*crypt_stat
,
915 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
)
917 struct ecryptfs_global_auth_tok
*global_auth_tok
;
920 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
921 list_for_each_entry(global_auth_tok
,
922 &mount_crypt_stat
->global_auth_tok_list
,
923 mount_crypt_stat_list
) {
924 rc
= ecryptfs_add_keysig(crypt_stat
, global_auth_tok
->sig
);
926 printk(KERN_ERR
"Error adding keysig; rc = [%d]\n", rc
);
928 &mount_crypt_stat
->global_auth_tok_list_mutex
);
932 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
938 * ecryptfs_set_default_crypt_stat_vals
939 * @crypt_stat: The inode's cryptographic context
940 * @mount_crypt_stat: The mount point's cryptographic context
942 * Default values in the event that policy does not override them.
944 static void ecryptfs_set_default_crypt_stat_vals(
945 struct ecryptfs_crypt_stat
*crypt_stat
,
946 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
)
948 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat
,
950 ecryptfs_set_default_sizes(crypt_stat
);
951 strcpy(crypt_stat
->cipher
, ECRYPTFS_DEFAULT_CIPHER
);
952 crypt_stat
->key_size
= ECRYPTFS_DEFAULT_KEY_BYTES
;
953 crypt_stat
->flags
&= ~(ECRYPTFS_KEY_VALID
);
954 crypt_stat
->file_version
= ECRYPTFS_FILE_VERSION
;
955 crypt_stat
->mount_crypt_stat
= mount_crypt_stat
;
959 * ecryptfs_new_file_context
960 * @ecryptfs_dentry: The eCryptfs dentry
962 * If the crypto context for the file has not yet been established,
963 * this is where we do that. Establishing a new crypto context
964 * involves the following decisions:
965 * - What cipher to use?
966 * - What set of authentication tokens to use?
967 * Here we just worry about getting enough information into the
968 * authentication tokens so that we know that they are available.
969 * We associate the available authentication tokens with the new file
970 * via the set of signatures in the crypt_stat struct. Later, when
971 * the headers are actually written out, we may again defer to
972 * userspace to perform the encryption of the session key; for the
973 * foreseeable future, this will be the case with public key packets.
975 * Returns zero on success; non-zero otherwise
977 int ecryptfs_new_file_context(struct dentry
*ecryptfs_dentry
)
979 struct ecryptfs_crypt_stat
*crypt_stat
=
980 &ecryptfs_inode_to_private(ecryptfs_dentry
->d_inode
)->crypt_stat
;
981 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
982 &ecryptfs_superblock_to_private(
983 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
987 ecryptfs_set_default_crypt_stat_vals(crypt_stat
, mount_crypt_stat
);
988 crypt_stat
->flags
|= (ECRYPTFS_ENCRYPTED
| ECRYPTFS_KEY_VALID
);
989 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat
,
991 rc
= ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat
,
994 printk(KERN_ERR
"Error attempting to copy mount-wide key sigs "
995 "to the inode key sigs; rc = [%d]\n", rc
);
999 strlen(mount_crypt_stat
->global_default_cipher_name
);
1000 memcpy(crypt_stat
->cipher
,
1001 mount_crypt_stat
->global_default_cipher_name
,
1003 crypt_stat
->cipher
[cipher_name_len
] = '\0';
1004 crypt_stat
->key_size
=
1005 mount_crypt_stat
->global_default_cipher_key_size
;
1006 ecryptfs_generate_new_key(crypt_stat
);
1007 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1009 ecryptfs_printk(KERN_ERR
, "Error initializing cryptographic "
1010 "context for cipher [%s]: rc = [%d]\n",
1011 crypt_stat
->cipher
, rc
);
1017 * contains_ecryptfs_marker - check for the ecryptfs marker
1018 * @data: The data block in which to check
1020 * Returns one if marker found; zero if not found
1022 static int contains_ecryptfs_marker(char *data
)
1026 memcpy(&m_1
, data
, 4);
1027 m_1
= be32_to_cpu(m_1
);
1028 memcpy(&m_2
, (data
+ 4), 4);
1029 m_2
= be32_to_cpu(m_2
);
1030 if ((m_1
^ MAGIC_ECRYPTFS_MARKER
) == m_2
)
1032 ecryptfs_printk(KERN_DEBUG
, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1033 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1
, m_2
,
1034 MAGIC_ECRYPTFS_MARKER
);
1035 ecryptfs_printk(KERN_DEBUG
, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1036 "[0x%.8x]\n", (m_1
^ MAGIC_ECRYPTFS_MARKER
));
1040 struct ecryptfs_flag_map_elem
{
1045 /* Add support for additional flags by adding elements here. */
1046 static struct ecryptfs_flag_map_elem ecryptfs_flag_map
[] = {
1047 {0x00000001, ECRYPTFS_ENABLE_HMAC
},
1048 {0x00000002, ECRYPTFS_ENCRYPTED
},
1049 {0x00000004, ECRYPTFS_METADATA_IN_XATTR
}
1053 * ecryptfs_process_flags
1054 * @crypt_stat: The cryptographic context
1055 * @page_virt: Source data to be parsed
1056 * @bytes_read: Updated with the number of bytes read
1058 * Returns zero on success; non-zero if the flag set is invalid
1060 static int ecryptfs_process_flags(struct ecryptfs_crypt_stat
*crypt_stat
,
1061 char *page_virt
, int *bytes_read
)
1067 memcpy(&flags
, page_virt
, 4);
1068 flags
= be32_to_cpu(flags
);
1069 for (i
= 0; i
< ((sizeof(ecryptfs_flag_map
)
1070 / sizeof(struct ecryptfs_flag_map_elem
))); i
++)
1071 if (flags
& ecryptfs_flag_map
[i
].file_flag
) {
1072 crypt_stat
->flags
|= ecryptfs_flag_map
[i
].local_flag
;
1074 crypt_stat
->flags
&= ~(ecryptfs_flag_map
[i
].local_flag
);
1075 /* Version is in top 8 bits of the 32-bit flag vector */
1076 crypt_stat
->file_version
= ((flags
>> 24) & 0xFF);
1082 * write_ecryptfs_marker
1083 * @page_virt: The pointer to in a page to begin writing the marker
1084 * @written: Number of bytes written
1086 * Marker = 0x3c81b7f5
1088 static void write_ecryptfs_marker(char *page_virt
, size_t *written
)
1092 get_random_bytes(&m_1
, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
/ 2));
1093 m_2
= (m_1
^ MAGIC_ECRYPTFS_MARKER
);
1094 m_1
= cpu_to_be32(m_1
);
1095 memcpy(page_virt
, &m_1
, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
/ 2));
1096 m_2
= cpu_to_be32(m_2
);
1097 memcpy(page_virt
+ (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
/ 2), &m_2
,
1098 (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
/ 2));
1099 (*written
) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
;
1103 write_ecryptfs_flags(char *page_virt
, struct ecryptfs_crypt_stat
*crypt_stat
,
1109 for (i
= 0; i
< ((sizeof(ecryptfs_flag_map
)
1110 / sizeof(struct ecryptfs_flag_map_elem
))); i
++)
1111 if (crypt_stat
->flags
& ecryptfs_flag_map
[i
].local_flag
)
1112 flags
|= ecryptfs_flag_map
[i
].file_flag
;
1113 /* Version is in top 8 bits of the 32-bit flag vector */
1114 flags
|= ((((u8
)crypt_stat
->file_version
) << 24) & 0xFF000000);
1115 flags
= cpu_to_be32(flags
);
1116 memcpy(page_virt
, &flags
, 4);
1120 struct ecryptfs_cipher_code_str_map_elem
{
1121 char cipher_str
[16];
1125 /* Add support for additional ciphers by adding elements here. The
1126 * cipher_code is whatever OpenPGP applicatoins use to identify the
1127 * ciphers. List in order of probability. */
1128 static struct ecryptfs_cipher_code_str_map_elem
1129 ecryptfs_cipher_code_str_map
[] = {
1130 {"aes",RFC2440_CIPHER_AES_128
},
1131 {"blowfish", RFC2440_CIPHER_BLOWFISH
},
1132 {"des3_ede", RFC2440_CIPHER_DES3_EDE
},
1133 {"cast5", RFC2440_CIPHER_CAST_5
},
1134 {"twofish", RFC2440_CIPHER_TWOFISH
},
1135 {"cast6", RFC2440_CIPHER_CAST_6
},
1136 {"aes", RFC2440_CIPHER_AES_192
},
1137 {"aes", RFC2440_CIPHER_AES_256
}
1141 * ecryptfs_code_for_cipher_string
1142 * @crypt_stat: The cryptographic context
1144 * Returns zero on no match, or the cipher code on match
1146 u16
ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat
*crypt_stat
)
1150 struct ecryptfs_cipher_code_str_map_elem
*map
=
1151 ecryptfs_cipher_code_str_map
;
1153 if (strcmp(crypt_stat
->cipher
, "aes") == 0) {
1154 switch (crypt_stat
->key_size
) {
1156 code
= RFC2440_CIPHER_AES_128
;
1159 code
= RFC2440_CIPHER_AES_192
;
1162 code
= RFC2440_CIPHER_AES_256
;
1165 for (i
= 0; i
< ARRAY_SIZE(ecryptfs_cipher_code_str_map
); i
++)
1166 if (strcmp(crypt_stat
->cipher
, map
[i
].cipher_str
) == 0){
1167 code
= map
[i
].cipher_code
;
1175 * ecryptfs_cipher_code_to_string
1176 * @str: Destination to write out the cipher name
1177 * @cipher_code: The code to convert to cipher name string
1179 * Returns zero on success
1181 int ecryptfs_cipher_code_to_string(char *str
, u16 cipher_code
)
1187 for (i
= 0; i
< ARRAY_SIZE(ecryptfs_cipher_code_str_map
); i
++)
1188 if (cipher_code
== ecryptfs_cipher_code_str_map
[i
].cipher_code
)
1189 strcpy(str
, ecryptfs_cipher_code_str_map
[i
].cipher_str
);
1190 if (str
[0] == '\0') {
1191 ecryptfs_printk(KERN_WARNING
, "Cipher code not recognized: "
1192 "[%d]\n", cipher_code
);
1198 int ecryptfs_read_and_validate_header_region(char *data
,
1199 struct inode
*ecryptfs_inode
)
1201 struct ecryptfs_crypt_stat
*crypt_stat
=
1202 &(ecryptfs_inode_to_private(ecryptfs_inode
)->crypt_stat
);
1205 rc
= ecryptfs_read_lower(data
, 0, crypt_stat
->extent_size
,
1208 printk(KERN_ERR
"%s: Error reading header region; rc = [%d]\n",
1212 if (!contains_ecryptfs_marker(data
+ ECRYPTFS_FILE_SIZE_BYTES
)) {
1214 ecryptfs_printk(KERN_DEBUG
, "Valid marker not found\n");
1221 ecryptfs_write_header_metadata(char *virt
,
1222 struct ecryptfs_crypt_stat
*crypt_stat
,
1225 u32 header_extent_size
;
1226 u16 num_header_extents_at_front
;
1228 header_extent_size
= (u32
)crypt_stat
->extent_size
;
1229 num_header_extents_at_front
=
1230 (u16
)crypt_stat
->num_header_extents_at_front
;
1231 header_extent_size
= cpu_to_be32(header_extent_size
);
1232 memcpy(virt
, &header_extent_size
, 4);
1234 num_header_extents_at_front
= cpu_to_be16(num_header_extents_at_front
);
1235 memcpy(virt
, &num_header_extents_at_front
, 2);
1239 struct kmem_cache
*ecryptfs_header_cache_0
;
1240 struct kmem_cache
*ecryptfs_header_cache_1
;
1241 struct kmem_cache
*ecryptfs_header_cache_2
;
1244 * ecryptfs_write_headers_virt
1245 * @page_virt: The virtual address to write the headers to
1246 * @size: Set to the number of bytes written by this function
1247 * @crypt_stat: The cryptographic context
1248 * @ecryptfs_dentry: The eCryptfs dentry
1253 * Octets 0-7: Unencrypted file size (big-endian)
1254 * Octets 8-15: eCryptfs special marker
1255 * Octets 16-19: Flags
1256 * Octet 16: File format version number (between 0 and 255)
1257 * Octets 17-18: Reserved
1258 * Octet 19: Bit 1 (lsb): Reserved
1260 * Bits 3-8: Reserved
1261 * Octets 20-23: Header extent size (big-endian)
1262 * Octets 24-25: Number of header extents at front of file
1264 * Octet 26: Begin RFC 2440 authentication token packet set
1266 * Lower data (CBC encrypted)
1268 * Lower data (CBC encrypted)
1271 * Returns zero on success
1273 static int ecryptfs_write_headers_virt(char *page_virt
, size_t *size
,
1274 struct ecryptfs_crypt_stat
*crypt_stat
,
1275 struct dentry
*ecryptfs_dentry
)
1281 offset
= ECRYPTFS_FILE_SIZE_BYTES
;
1282 write_ecryptfs_marker((page_virt
+ offset
), &written
);
1284 write_ecryptfs_flags((page_virt
+ offset
), crypt_stat
, &written
);
1286 ecryptfs_write_header_metadata((page_virt
+ offset
), crypt_stat
,
1289 rc
= ecryptfs_generate_key_packet_set((page_virt
+ offset
), crypt_stat
,
1290 ecryptfs_dentry
, &written
,
1291 PAGE_CACHE_SIZE
- offset
);
1293 ecryptfs_printk(KERN_WARNING
, "Error generating key packet "
1294 "set; rc = [%d]\n", rc
);
1303 ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat
*crypt_stat
,
1304 struct dentry
*ecryptfs_dentry
,
1307 int current_header_page
;
1311 rc
= ecryptfs_write_lower(ecryptfs_dentry
->d_inode
, page_virt
,
1312 0, PAGE_CACHE_SIZE
);
1314 printk(KERN_ERR
"%s: Error attempting to write header "
1315 "information to lower file; rc = [%d]\n", __FUNCTION__
,
1319 header_pages
= ((crypt_stat
->extent_size
1320 * crypt_stat
->num_header_extents_at_front
)
1322 memset(page_virt
, 0, PAGE_CACHE_SIZE
);
1323 current_header_page
= 1;
1324 while (current_header_page
< header_pages
) {
1327 offset
= (((loff_t
)current_header_page
) << PAGE_CACHE_SHIFT
);
1328 if ((rc
= ecryptfs_write_lower(ecryptfs_dentry
->d_inode
,
1330 PAGE_CACHE_SIZE
))) {
1331 printk(KERN_ERR
"%s: Error attempting to write header "
1332 "information to lower file; rc = [%d]\n",
1336 current_header_page
++;
1343 ecryptfs_write_metadata_to_xattr(struct dentry
*ecryptfs_dentry
,
1344 struct ecryptfs_crypt_stat
*crypt_stat
,
1345 char *page_virt
, size_t size
)
1349 rc
= ecryptfs_setxattr(ecryptfs_dentry
, ECRYPTFS_XATTR_NAME
, page_virt
,
1355 * ecryptfs_write_metadata
1356 * @ecryptfs_dentry: The eCryptfs dentry
1358 * Write the file headers out. This will likely involve a userspace
1359 * callout, in which the session key is encrypted with one or more
1360 * public keys and/or the passphrase necessary to do the encryption is
1361 * retrieved via a prompt. Exactly what happens at this point should
1362 * be policy-dependent.
1364 * TODO: Support header information spanning multiple pages
1366 * Returns zero on success; non-zero on error
1368 int ecryptfs_write_metadata(struct dentry
*ecryptfs_dentry
)
1370 struct ecryptfs_crypt_stat
*crypt_stat
=
1371 &ecryptfs_inode_to_private(ecryptfs_dentry
->d_inode
)->crypt_stat
;
1376 if (likely(crypt_stat
->flags
& ECRYPTFS_ENCRYPTED
)) {
1377 if (!(crypt_stat
->flags
& ECRYPTFS_KEY_VALID
)) {
1378 printk(KERN_ERR
"Key is invalid; bailing out\n");
1384 ecryptfs_printk(KERN_WARNING
,
1385 "Called with crypt_stat->encrypted == 0\n");
1388 /* Released in this function */
1389 page_virt
= kmem_cache_zalloc(ecryptfs_header_cache_0
, GFP_USER
);
1391 ecryptfs_printk(KERN_ERR
, "Out of memory\n");
1395 rc
= ecryptfs_write_headers_virt(page_virt
, &size
, crypt_stat
,
1398 ecryptfs_printk(KERN_ERR
, "Error whilst writing headers\n");
1399 memset(page_virt
, 0, PAGE_CACHE_SIZE
);
1402 if (crypt_stat
->flags
& ECRYPTFS_METADATA_IN_XATTR
)
1403 rc
= ecryptfs_write_metadata_to_xattr(ecryptfs_dentry
,
1404 crypt_stat
, page_virt
,
1407 rc
= ecryptfs_write_metadata_to_contents(crypt_stat
,
1411 printk(KERN_ERR
"Error writing metadata out to lower file; "
1416 kmem_cache_free(ecryptfs_header_cache_0
, page_virt
);
1421 #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1422 #define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1423 static int parse_header_metadata(struct ecryptfs_crypt_stat
*crypt_stat
,
1424 char *virt
, int *bytes_read
,
1425 int validate_header_size
)
1428 u32 header_extent_size
;
1429 u16 num_header_extents_at_front
;
1431 memcpy(&header_extent_size
, virt
, sizeof(u32
));
1432 header_extent_size
= be32_to_cpu(header_extent_size
);
1433 virt
+= sizeof(u32
);
1434 memcpy(&num_header_extents_at_front
, virt
, sizeof(u16
));
1435 num_header_extents_at_front
= be16_to_cpu(num_header_extents_at_front
);
1436 crypt_stat
->num_header_extents_at_front
=
1437 (int)num_header_extents_at_front
;
1438 (*bytes_read
) = (sizeof(u32
) + sizeof(u16
));
1439 if ((validate_header_size
== ECRYPTFS_VALIDATE_HEADER_SIZE
)
1440 && ((crypt_stat
->extent_size
1441 * crypt_stat
->num_header_extents_at_front
)
1442 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
)) {
1444 printk(KERN_WARNING
"Invalid number of header extents: [%zd]\n",
1445 crypt_stat
->num_header_extents_at_front
);
1451 * set_default_header_data
1452 * @crypt_stat: The cryptographic context
1454 * For version 0 file format; this function is only for backwards
1455 * compatibility for files created with the prior versions of
1458 static void set_default_header_data(struct ecryptfs_crypt_stat
*crypt_stat
)
1460 crypt_stat
->num_header_extents_at_front
= 2;
1464 * ecryptfs_read_headers_virt
1465 * @page_virt: The virtual address into which to read the headers
1466 * @crypt_stat: The cryptographic context
1467 * @ecryptfs_dentry: The eCryptfs dentry
1468 * @validate_header_size: Whether to validate the header size while reading
1470 * Read/parse the header data. The header format is detailed in the
1471 * comment block for the ecryptfs_write_headers_virt() function.
1473 * Returns zero on success
1475 static int ecryptfs_read_headers_virt(char *page_virt
,
1476 struct ecryptfs_crypt_stat
*crypt_stat
,
1477 struct dentry
*ecryptfs_dentry
,
1478 int validate_header_size
)
1484 ecryptfs_set_default_sizes(crypt_stat
);
1485 crypt_stat
->mount_crypt_stat
= &ecryptfs_superblock_to_private(
1486 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
1487 offset
= ECRYPTFS_FILE_SIZE_BYTES
;
1488 rc
= contains_ecryptfs_marker(page_virt
+ offset
);
1493 offset
+= MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
;
1494 rc
= ecryptfs_process_flags(crypt_stat
, (page_virt
+ offset
),
1497 ecryptfs_printk(KERN_WARNING
, "Error processing flags\n");
1500 if (crypt_stat
->file_version
> ECRYPTFS_SUPPORTED_FILE_VERSION
) {
1501 ecryptfs_printk(KERN_WARNING
, "File version is [%d]; only "
1502 "file version [%d] is supported by this "
1503 "version of eCryptfs\n",
1504 crypt_stat
->file_version
,
1505 ECRYPTFS_SUPPORTED_FILE_VERSION
);
1509 offset
+= bytes_read
;
1510 if (crypt_stat
->file_version
>= 1) {
1511 rc
= parse_header_metadata(crypt_stat
, (page_virt
+ offset
),
1512 &bytes_read
, validate_header_size
);
1514 ecryptfs_printk(KERN_WARNING
, "Error reading header "
1515 "metadata; rc = [%d]\n", rc
);
1517 offset
+= bytes_read
;
1519 set_default_header_data(crypt_stat
);
1520 rc
= ecryptfs_parse_packet_set(crypt_stat
, (page_virt
+ offset
),
1527 * ecryptfs_read_xattr_region
1528 * @page_virt: The vitual address into which to read the xattr data
1529 * @ecryptfs_inode: The eCryptfs inode
1531 * Attempts to read the crypto metadata from the extended attribute
1532 * region of the lower file.
1534 * Returns zero on success; non-zero on error
1536 int ecryptfs_read_xattr_region(char *page_virt
, struct inode
*ecryptfs_inode
)
1538 struct dentry
*lower_dentry
=
1539 ecryptfs_inode_to_private(ecryptfs_inode
)->lower_file
->f_dentry
;
1543 size
= ecryptfs_getxattr_lower(lower_dentry
, ECRYPTFS_XATTR_NAME
,
1544 page_virt
, ECRYPTFS_DEFAULT_EXTENT_SIZE
);
1546 printk(KERN_ERR
"Error attempting to read the [%s] "
1547 "xattr from the lower file; return value = [%zd]\n",
1548 ECRYPTFS_XATTR_NAME
, size
);
1556 int ecryptfs_read_and_validate_xattr_region(char *page_virt
,
1557 struct dentry
*ecryptfs_dentry
)
1561 rc
= ecryptfs_read_xattr_region(page_virt
, ecryptfs_dentry
->d_inode
);
1564 if (!contains_ecryptfs_marker(page_virt
+ ECRYPTFS_FILE_SIZE_BYTES
)) {
1565 printk(KERN_WARNING
"Valid data found in [%s] xattr, but "
1566 "the marker is invalid\n", ECRYPTFS_XATTR_NAME
);
1574 * ecryptfs_read_metadata
1576 * Common entry point for reading file metadata. From here, we could
1577 * retrieve the header information from the header region of the file,
1578 * the xattr region of the file, or some other repostory that is
1579 * stored separately from the file itself. The current implementation
1580 * supports retrieving the metadata information from the file contents
1581 * and from the xattr region.
1583 * Returns zero if valid headers found and parsed; non-zero otherwise
1585 int ecryptfs_read_metadata(struct dentry
*ecryptfs_dentry
)
1588 char *page_virt
= NULL
;
1589 struct inode
*ecryptfs_inode
= ecryptfs_dentry
->d_inode
;
1590 struct ecryptfs_crypt_stat
*crypt_stat
=
1591 &ecryptfs_inode_to_private(ecryptfs_inode
)->crypt_stat
;
1592 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1593 &ecryptfs_superblock_to_private(
1594 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
1596 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat
,
1598 /* Read the first page from the underlying file */
1599 page_virt
= kmem_cache_alloc(ecryptfs_header_cache_1
, GFP_USER
);
1602 printk(KERN_ERR
"%s: Unable to allocate page_virt\n",
1606 rc
= ecryptfs_read_lower(page_virt
, 0, crypt_stat
->extent_size
,
1609 rc
= ecryptfs_read_headers_virt(page_virt
, crypt_stat
,
1611 ECRYPTFS_VALIDATE_HEADER_SIZE
);
1613 rc
= ecryptfs_read_xattr_region(page_virt
, ecryptfs_inode
);
1615 printk(KERN_DEBUG
"Valid eCryptfs headers not found in "
1616 "file header region or xattr region\n");
1620 rc
= ecryptfs_read_headers_virt(page_virt
, crypt_stat
,
1622 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE
);
1624 printk(KERN_DEBUG
"Valid eCryptfs headers not found in "
1625 "file xattr region either\n");
1628 if (crypt_stat
->mount_crypt_stat
->flags
1629 & ECRYPTFS_XATTR_METADATA_ENABLED
) {
1630 crypt_stat
->flags
|= ECRYPTFS_METADATA_IN_XATTR
;
1632 printk(KERN_WARNING
"Attempt to access file with "
1633 "crypto metadata only in the extended attribute "
1634 "region, but eCryptfs was mounted without "
1635 "xattr support enabled. eCryptfs will not treat "
1636 "this like an encrypted file.\n");
1642 memset(page_virt
, 0, PAGE_CACHE_SIZE
);
1643 kmem_cache_free(ecryptfs_header_cache_1
, page_virt
);
1649 * ecryptfs_encode_filename - converts a plaintext file name to cipher text
1650 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
1651 * @name: The plaintext name
1652 * @length: The length of the plaintext
1653 * @encoded_name: The encypted name
1655 * Encrypts and encodes a filename into something that constitutes a
1656 * valid filename for a filesystem, with printable characters.
1658 * We assume that we have a properly initialized crypto context,
1659 * pointed to by crypt_stat->tfm.
1661 * TODO: Implement filename decoding and decryption here, in place of
1662 * memcpy. We are keeping the framework around for now to (1)
1663 * facilitate testing of the components needed to implement filename
1664 * encryption and (2) to provide a code base from which other
1665 * developers in the community can easily implement this feature.
1667 * Returns the length of encoded filename; negative if error
1670 ecryptfs_encode_filename(struct ecryptfs_crypt_stat
*crypt_stat
,
1671 const char *name
, int length
, char **encoded_name
)
1675 (*encoded_name
) = kmalloc(length
+ 2, GFP_KERNEL
);
1676 if (!(*encoded_name
)) {
1680 /* TODO: Filename encryption is a scheduled feature for a
1681 * future version of eCryptfs. This function is here only for
1682 * the purpose of providing a framework for other developers
1683 * to easily implement filename encryption. Hint: Replace this
1684 * memcpy() with a call to encrypt and encode the
1685 * filename, the set the length accordingly. */
1686 memcpy((void *)(*encoded_name
), (void *)name
, length
);
1687 (*encoded_name
)[length
] = '\0';
1694 * ecryptfs_decode_filename - converts the cipher text name to plaintext
1695 * @crypt_stat: The crypt_stat struct associated with the file
1696 * @name: The filename in cipher text
1697 * @length: The length of the cipher text name
1698 * @decrypted_name: The plaintext name
1700 * Decodes and decrypts the filename.
1702 * We assume that we have a properly initialized crypto context,
1703 * pointed to by crypt_stat->tfm.
1705 * TODO: Implement filename decoding and decryption here, in place of
1706 * memcpy. We are keeping the framework around for now to (1)
1707 * facilitate testing of the components needed to implement filename
1708 * encryption and (2) to provide a code base from which other
1709 * developers in the community can easily implement this feature.
1711 * Returns the length of decoded filename; negative if error
1714 ecryptfs_decode_filename(struct ecryptfs_crypt_stat
*crypt_stat
,
1715 const char *name
, int length
, char **decrypted_name
)
1719 (*decrypted_name
) = kmalloc(length
+ 2, GFP_KERNEL
);
1720 if (!(*decrypted_name
)) {
1724 /* TODO: Filename encryption is a scheduled feature for a
1725 * future version of eCryptfs. This function is here only for
1726 * the purpose of providing a framework for other developers
1727 * to easily implement filename encryption. Hint: Replace this
1728 * memcpy() with a call to decode and decrypt the
1729 * filename, the set the length accordingly. */
1730 memcpy((void *)(*decrypted_name
), (void *)name
, length
);
1731 (*decrypted_name
)[length
+ 1] = '\0'; /* Only for convenience
1732 * in printing out the
1741 * ecryptfs_process_key_cipher - Perform key cipher initialization.
1742 * @key_tfm: Crypto context for key material, set by this function
1743 * @cipher_name: Name of the cipher
1744 * @key_size: Size of the key in bytes
1746 * Returns zero on success. Any crypto_tfm structs allocated here
1747 * should be released by other functions, such as on a superblock put
1748 * event, regardless of whether this function succeeds for fails.
1751 ecryptfs_process_key_cipher(struct crypto_blkcipher
**key_tfm
,
1752 char *cipher_name
, size_t *key_size
)
1754 char dummy_key
[ECRYPTFS_MAX_KEY_BYTES
];
1755 char *full_alg_name
;
1759 if (*key_size
> ECRYPTFS_MAX_KEY_BYTES
) {
1761 printk(KERN_ERR
"Requested key size is [%Zd] bytes; maximum "
1762 "allowable is [%d]\n", *key_size
, ECRYPTFS_MAX_KEY_BYTES
);
1765 rc
= ecryptfs_crypto_api_algify_cipher_name(&full_alg_name
, cipher_name
,
1769 *key_tfm
= crypto_alloc_blkcipher(full_alg_name
, 0, CRYPTO_ALG_ASYNC
);
1770 kfree(full_alg_name
);
1771 if (IS_ERR(*key_tfm
)) {
1772 rc
= PTR_ERR(*key_tfm
);
1773 printk(KERN_ERR
"Unable to allocate crypto cipher with name "
1774 "[%s]; rc = [%d]\n", cipher_name
, rc
);
1777 crypto_blkcipher_set_flags(*key_tfm
, CRYPTO_TFM_REQ_WEAK_KEY
);
1778 if (*key_size
== 0) {
1779 struct blkcipher_alg
*alg
= crypto_blkcipher_alg(*key_tfm
);
1781 *key_size
= alg
->max_keysize
;
1783 get_random_bytes(dummy_key
, *key_size
);
1784 rc
= crypto_blkcipher_setkey(*key_tfm
, dummy_key
, *key_size
);
1786 printk(KERN_ERR
"Error attempting to set key of size [%Zd] for "
1787 "cipher [%s]; rc = [%d]\n", *key_size
, cipher_name
, rc
);
1795 struct kmem_cache
*ecryptfs_key_tfm_cache
;
1796 struct list_head key_tfm_list
;
1797 struct mutex key_tfm_list_mutex
;
1799 int ecryptfs_init_crypto(void)
1801 mutex_init(&key_tfm_list_mutex
);
1802 INIT_LIST_HEAD(&key_tfm_list
);
1806 int ecryptfs_destroy_crypto(void)
1808 struct ecryptfs_key_tfm
*key_tfm
, *key_tfm_tmp
;
1810 mutex_lock(&key_tfm_list_mutex
);
1811 list_for_each_entry_safe(key_tfm
, key_tfm_tmp
, &key_tfm_list
,
1813 list_del(&key_tfm
->key_tfm_list
);
1814 if (key_tfm
->key_tfm
)
1815 crypto_free_blkcipher(key_tfm
->key_tfm
);
1816 kmem_cache_free(ecryptfs_key_tfm_cache
, key_tfm
);
1818 mutex_unlock(&key_tfm_list_mutex
);
1823 ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm
**key_tfm
, char *cipher_name
,
1826 struct ecryptfs_key_tfm
*tmp_tfm
;
1829 tmp_tfm
= kmem_cache_alloc(ecryptfs_key_tfm_cache
, GFP_KERNEL
);
1830 if (key_tfm
!= NULL
)
1831 (*key_tfm
) = tmp_tfm
;
1834 printk(KERN_ERR
"Error attempting to allocate from "
1835 "ecryptfs_key_tfm_cache\n");
1838 mutex_init(&tmp_tfm
->key_tfm_mutex
);
1839 strncpy(tmp_tfm
->cipher_name
, cipher_name
,
1840 ECRYPTFS_MAX_CIPHER_NAME_SIZE
);
1841 tmp_tfm
->key_size
= key_size
;
1842 rc
= ecryptfs_process_key_cipher(&tmp_tfm
->key_tfm
,
1843 tmp_tfm
->cipher_name
,
1844 &tmp_tfm
->key_size
);
1846 printk(KERN_ERR
"Error attempting to initialize key TFM "
1847 "cipher with name = [%s]; rc = [%d]\n",
1848 tmp_tfm
->cipher_name
, rc
);
1849 kmem_cache_free(ecryptfs_key_tfm_cache
, tmp_tfm
);
1850 if (key_tfm
!= NULL
)
1854 mutex_lock(&key_tfm_list_mutex
);
1855 list_add(&tmp_tfm
->key_tfm_list
, &key_tfm_list
);
1856 mutex_unlock(&key_tfm_list_mutex
);
1861 int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher
**tfm
,
1862 struct mutex
**tfm_mutex
,
1865 struct ecryptfs_key_tfm
*key_tfm
;
1869 (*tfm_mutex
) = NULL
;
1870 mutex_lock(&key_tfm_list_mutex
);
1871 list_for_each_entry(key_tfm
, &key_tfm_list
, key_tfm_list
) {
1872 if (strcmp(key_tfm
->cipher_name
, cipher_name
) == 0) {
1873 (*tfm
) = key_tfm
->key_tfm
;
1874 (*tfm_mutex
) = &key_tfm
->key_tfm_mutex
;
1875 mutex_unlock(&key_tfm_list_mutex
);
1879 mutex_unlock(&key_tfm_list_mutex
);
1880 rc
= ecryptfs_add_new_key_tfm(&key_tfm
, cipher_name
, 0);
1882 printk(KERN_ERR
"Error adding new key_tfm to list; rc = [%d]\n",
1886 (*tfm
) = key_tfm
->key_tfm
;
1887 (*tfm_mutex
) = &key_tfm
->key_tfm_mutex
;