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 <asm/unaligned.h>
37 #include "ecryptfs_kernel.h"
40 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat
*crypt_stat
,
41 struct page
*dst_page
, int dst_offset
,
42 struct page
*src_page
, int src_offset
, int size
,
45 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat
*crypt_stat
,
46 struct page
*dst_page
, int dst_offset
,
47 struct page
*src_page
, int src_offset
, int size
,
52 * @dst: Buffer to take hex character representation of contents of
53 * src; must be at least of size (src_size * 2)
54 * @src: Buffer to be converted to a hex string respresentation
55 * @src_size: number of bytes to convert
57 void ecryptfs_to_hex(char *dst
, char *src
, size_t src_size
)
61 for (x
= 0; x
< src_size
; x
++)
62 sprintf(&dst
[x
* 2], "%.2x", (unsigned char)src
[x
]);
67 * @dst: Buffer to take the bytes from src hex; must be at least of
69 * @src: Buffer to be converted from a hex string respresentation to raw value
70 * @dst_size: size of dst buffer, or number of hex characters pairs to convert
72 void ecryptfs_from_hex(char *dst
, char *src
, int dst_size
)
77 for (x
= 0; x
< dst_size
; x
++) {
79 tmp
[1] = src
[x
* 2 + 1];
80 dst
[x
] = (unsigned char)simple_strtol(tmp
, NULL
, 16);
85 * ecryptfs_calculate_md5 - calculates the md5 of @src
86 * @dst: Pointer to 16 bytes of allocated memory
87 * @crypt_stat: Pointer to crypt_stat struct for the current inode
88 * @src: Data to be md5'd
89 * @len: Length of @src
91 * Uses the allocated crypto context that crypt_stat references to
92 * generate the MD5 sum of the contents of src.
94 static int ecryptfs_calculate_md5(char *dst
,
95 struct ecryptfs_crypt_stat
*crypt_stat
,
98 struct scatterlist sg
;
99 struct hash_desc desc
= {
100 .tfm
= crypt_stat
->hash_tfm
,
101 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
105 mutex_lock(&crypt_stat
->cs_hash_tfm_mutex
);
106 sg_init_one(&sg
, (u8
*)src
, len
);
108 desc
.tfm
= crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH
, 0,
110 if (IS_ERR(desc
.tfm
)) {
111 rc
= PTR_ERR(desc
.tfm
);
112 ecryptfs_printk(KERN_ERR
, "Error attempting to "
113 "allocate crypto context; rc = [%d]\n",
117 crypt_stat
->hash_tfm
= desc
.tfm
;
119 rc
= crypto_hash_init(&desc
);
122 "%s: Error initializing crypto hash; rc = [%d]\n",
126 rc
= crypto_hash_update(&desc
, &sg
, len
);
129 "%s: Error updating crypto hash; rc = [%d]\n",
133 rc
= crypto_hash_final(&desc
, dst
);
136 "%s: Error finalizing crypto hash; rc = [%d]\n",
141 mutex_unlock(&crypt_stat
->cs_hash_tfm_mutex
);
145 static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name
,
147 char *chaining_modifier
)
149 int cipher_name_len
= strlen(cipher_name
);
150 int chaining_modifier_len
= strlen(chaining_modifier
);
151 int algified_name_len
;
154 algified_name_len
= (chaining_modifier_len
+ cipher_name_len
+ 3);
155 (*algified_name
) = kmalloc(algified_name_len
, GFP_KERNEL
);
156 if (!(*algified_name
)) {
160 snprintf((*algified_name
), algified_name_len
, "%s(%s)",
161 chaining_modifier
, cipher_name
);
169 * @iv: destination for the derived iv vale
170 * @crypt_stat: Pointer to crypt_stat struct for the current inode
171 * @offset: Offset of the extent whose IV we are to derive
173 * Generate the initialization vector from the given root IV and page
176 * Returns zero on success; non-zero on error.
178 static int ecryptfs_derive_iv(char *iv
, struct ecryptfs_crypt_stat
*crypt_stat
,
182 char dst
[MD5_DIGEST_SIZE
];
183 char src
[ECRYPTFS_MAX_IV_BYTES
+ 16];
185 if (unlikely(ecryptfs_verbosity
> 0)) {
186 ecryptfs_printk(KERN_DEBUG
, "root iv:\n");
187 ecryptfs_dump_hex(crypt_stat
->root_iv
, crypt_stat
->iv_bytes
);
189 /* TODO: It is probably secure to just cast the least
190 * significant bits of the root IV into an unsigned long and
191 * add the offset to that rather than go through all this
192 * hashing business. -Halcrow */
193 memcpy(src
, crypt_stat
->root_iv
, crypt_stat
->iv_bytes
);
194 memset((src
+ crypt_stat
->iv_bytes
), 0, 16);
195 snprintf((src
+ crypt_stat
->iv_bytes
), 16, "%lld", offset
);
196 if (unlikely(ecryptfs_verbosity
> 0)) {
197 ecryptfs_printk(KERN_DEBUG
, "source:\n");
198 ecryptfs_dump_hex(src
, (crypt_stat
->iv_bytes
+ 16));
200 rc
= ecryptfs_calculate_md5(dst
, crypt_stat
, src
,
201 (crypt_stat
->iv_bytes
+ 16));
203 ecryptfs_printk(KERN_WARNING
, "Error attempting to compute "
204 "MD5 while generating IV for a page\n");
207 memcpy(iv
, dst
, crypt_stat
->iv_bytes
);
208 if (unlikely(ecryptfs_verbosity
> 0)) {
209 ecryptfs_printk(KERN_DEBUG
, "derived iv:\n");
210 ecryptfs_dump_hex(iv
, crypt_stat
->iv_bytes
);
217 * ecryptfs_init_crypt_stat
218 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
220 * Initialize the crypt_stat structure.
223 ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat
*crypt_stat
)
225 memset((void *)crypt_stat
, 0, sizeof(struct ecryptfs_crypt_stat
));
226 INIT_LIST_HEAD(&crypt_stat
->keysig_list
);
227 mutex_init(&crypt_stat
->keysig_list_mutex
);
228 mutex_init(&crypt_stat
->cs_mutex
);
229 mutex_init(&crypt_stat
->cs_tfm_mutex
);
230 mutex_init(&crypt_stat
->cs_hash_tfm_mutex
);
231 crypt_stat
->flags
|= ECRYPTFS_STRUCT_INITIALIZED
;
235 * ecryptfs_destroy_crypt_stat
236 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
238 * Releases all memory associated with a crypt_stat struct.
240 void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat
*crypt_stat
)
242 struct ecryptfs_key_sig
*key_sig
, *key_sig_tmp
;
245 crypto_free_blkcipher(crypt_stat
->tfm
);
246 if (crypt_stat
->hash_tfm
)
247 crypto_free_hash(crypt_stat
->hash_tfm
);
248 mutex_lock(&crypt_stat
->keysig_list_mutex
);
249 list_for_each_entry_safe(key_sig
, key_sig_tmp
,
250 &crypt_stat
->keysig_list
, crypt_stat_list
) {
251 list_del(&key_sig
->crypt_stat_list
);
252 kmem_cache_free(ecryptfs_key_sig_cache
, key_sig
);
254 mutex_unlock(&crypt_stat
->keysig_list_mutex
);
255 memset(crypt_stat
, 0, sizeof(struct ecryptfs_crypt_stat
));
258 void ecryptfs_destroy_mount_crypt_stat(
259 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
)
261 struct ecryptfs_global_auth_tok
*auth_tok
, *auth_tok_tmp
;
263 if (!(mount_crypt_stat
->flags
& ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED
))
265 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
266 list_for_each_entry_safe(auth_tok
, auth_tok_tmp
,
267 &mount_crypt_stat
->global_auth_tok_list
,
268 mount_crypt_stat_list
) {
269 list_del(&auth_tok
->mount_crypt_stat_list
);
270 mount_crypt_stat
->num_global_auth_toks
--;
271 if (auth_tok
->global_auth_tok_key
272 && !(auth_tok
->flags
& ECRYPTFS_AUTH_TOK_INVALID
))
273 key_put(auth_tok
->global_auth_tok_key
);
274 kmem_cache_free(ecryptfs_global_auth_tok_cache
, auth_tok
);
276 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
277 memset(mount_crypt_stat
, 0, sizeof(struct ecryptfs_mount_crypt_stat
));
281 * virt_to_scatterlist
282 * @addr: Virtual address
283 * @size: Size of data; should be an even multiple of the block size
284 * @sg: Pointer to scatterlist array; set to NULL to obtain only
285 * the number of scatterlist structs required in array
286 * @sg_size: Max array size
288 * Fills in a scatterlist array with page references for a passed
291 * Returns the number of scatterlist structs in array used
293 int virt_to_scatterlist(const void *addr
, int size
, struct scatterlist
*sg
,
299 int remainder_of_page
;
301 sg_init_table(sg
, sg_size
);
303 while (size
> 0 && i
< sg_size
) {
304 pg
= virt_to_page(addr
);
305 offset
= offset_in_page(addr
);
307 sg_set_page(&sg
[i
], pg
, 0, offset
);
308 remainder_of_page
= PAGE_CACHE_SIZE
- offset
;
309 if (size
>= remainder_of_page
) {
311 sg
[i
].length
= remainder_of_page
;
312 addr
+= remainder_of_page
;
313 size
-= remainder_of_page
;
328 * encrypt_scatterlist
329 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
330 * @dest_sg: Destination of encrypted data
331 * @src_sg: Data to be encrypted
332 * @size: Length of data to be encrypted
333 * @iv: iv to use during encryption
335 * Returns the number of bytes encrypted; negative value on error
337 static int encrypt_scatterlist(struct ecryptfs_crypt_stat
*crypt_stat
,
338 struct scatterlist
*dest_sg
,
339 struct scatterlist
*src_sg
, int size
,
342 struct blkcipher_desc desc
= {
343 .tfm
= crypt_stat
->tfm
,
345 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
349 BUG_ON(!crypt_stat
|| !crypt_stat
->tfm
350 || !(crypt_stat
->flags
& ECRYPTFS_STRUCT_INITIALIZED
));
351 if (unlikely(ecryptfs_verbosity
> 0)) {
352 ecryptfs_printk(KERN_DEBUG
, "Key size [%d]; key:\n",
353 crypt_stat
->key_size
);
354 ecryptfs_dump_hex(crypt_stat
->key
,
355 crypt_stat
->key_size
);
357 /* Consider doing this once, when the file is opened */
358 mutex_lock(&crypt_stat
->cs_tfm_mutex
);
359 if (!(crypt_stat
->flags
& ECRYPTFS_KEY_SET
)) {
360 rc
= crypto_blkcipher_setkey(crypt_stat
->tfm
, crypt_stat
->key
,
361 crypt_stat
->key_size
);
362 crypt_stat
->flags
|= ECRYPTFS_KEY_SET
;
365 ecryptfs_printk(KERN_ERR
, "Error setting key; rc = [%d]\n",
367 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
371 ecryptfs_printk(KERN_DEBUG
, "Encrypting [%d] bytes.\n", size
);
372 crypto_blkcipher_encrypt_iv(&desc
, dest_sg
, src_sg
, size
);
373 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
379 * ecryptfs_lower_offset_for_extent
381 * Convert an eCryptfs page index into a lower byte offset
383 static void ecryptfs_lower_offset_for_extent(loff_t
*offset
, loff_t extent_num
,
384 struct ecryptfs_crypt_stat
*crypt_stat
)
386 (*offset
) = (crypt_stat
->num_header_bytes_at_front
387 + (crypt_stat
->extent_size
* extent_num
));
391 * ecryptfs_encrypt_extent
392 * @enc_extent_page: Allocated page into which to encrypt the data in
394 * @crypt_stat: crypt_stat containing cryptographic context for the
395 * encryption operation
396 * @page: Page containing plaintext data extent to encrypt
397 * @extent_offset: Page extent offset for use in generating IV
399 * Encrypts one extent of data.
401 * Return zero on success; non-zero otherwise
403 static int ecryptfs_encrypt_extent(struct page
*enc_extent_page
,
404 struct ecryptfs_crypt_stat
*crypt_stat
,
406 unsigned long extent_offset
)
409 char extent_iv
[ECRYPTFS_MAX_IV_BYTES
];
412 extent_base
= (((loff_t
)page
->index
)
413 * (PAGE_CACHE_SIZE
/ crypt_stat
->extent_size
));
414 rc
= ecryptfs_derive_iv(extent_iv
, crypt_stat
,
415 (extent_base
+ extent_offset
));
417 ecryptfs_printk(KERN_ERR
, "Error attempting to "
418 "derive IV for extent [0x%.16x]; "
419 "rc = [%d]\n", (extent_base
+ extent_offset
),
423 if (unlikely(ecryptfs_verbosity
> 0)) {
424 ecryptfs_printk(KERN_DEBUG
, "Encrypting extent "
426 ecryptfs_dump_hex(extent_iv
, crypt_stat
->iv_bytes
);
427 ecryptfs_printk(KERN_DEBUG
, "First 8 bytes before "
429 ecryptfs_dump_hex((char *)
431 + (extent_offset
* crypt_stat
->extent_size
)),
434 rc
= ecryptfs_encrypt_page_offset(crypt_stat
, enc_extent_page
, 0,
436 * crypt_stat
->extent_size
),
437 crypt_stat
->extent_size
, extent_iv
);
439 printk(KERN_ERR
"%s: Error attempting to encrypt page with "
440 "page->index = [%ld], extent_offset = [%ld]; "
441 "rc = [%d]\n", __func__
, page
->index
, extent_offset
,
446 if (unlikely(ecryptfs_verbosity
> 0)) {
447 ecryptfs_printk(KERN_DEBUG
, "Encrypt extent [0x%.16x]; "
448 "rc = [%d]\n", (extent_base
+ extent_offset
),
450 ecryptfs_printk(KERN_DEBUG
, "First 8 bytes after "
452 ecryptfs_dump_hex((char *)(page_address(enc_extent_page
)), 8);
459 * ecryptfs_encrypt_page
460 * @page: Page mapped from the eCryptfs inode for the file; contains
461 * decrypted content that needs to be encrypted (to a temporary
462 * page; not in place) and written out to the lower file
464 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
465 * that eCryptfs pages may straddle the lower pages -- for instance,
466 * if the file was created on a machine with an 8K page size
467 * (resulting in an 8K header), and then the file is copied onto a
468 * host with a 32K page size, then when reading page 0 of the eCryptfs
469 * file, 24K of page 0 of the lower file will be read and decrypted,
470 * and then 8K of page 1 of the lower file will be read and decrypted.
472 * Returns zero on success; negative on error
474 int ecryptfs_encrypt_page(struct page
*page
)
476 struct inode
*ecryptfs_inode
;
477 struct ecryptfs_crypt_stat
*crypt_stat
;
478 char *enc_extent_virt
= NULL
;
479 struct page
*enc_extent_page
;
480 loff_t extent_offset
;
483 ecryptfs_inode
= page
->mapping
->host
;
485 &(ecryptfs_inode_to_private(ecryptfs_inode
)->crypt_stat
);
486 if (!(crypt_stat
->flags
& ECRYPTFS_ENCRYPTED
)) {
487 rc
= ecryptfs_write_lower_page_segment(ecryptfs_inode
, page
,
490 printk(KERN_ERR
"%s: Error attempting to copy "
491 "page at index [%ld]\n", __func__
,
495 enc_extent_virt
= kmalloc(PAGE_CACHE_SIZE
, GFP_USER
);
496 if (!enc_extent_virt
) {
498 ecryptfs_printk(KERN_ERR
, "Error allocating memory for "
499 "encrypted extent\n");
502 enc_extent_page
= virt_to_page(enc_extent_virt
);
503 for (extent_offset
= 0;
504 extent_offset
< (PAGE_CACHE_SIZE
/ crypt_stat
->extent_size
);
508 rc
= ecryptfs_encrypt_extent(enc_extent_page
, crypt_stat
, page
,
511 printk(KERN_ERR
"%s: Error encrypting extent; "
512 "rc = [%d]\n", __func__
, rc
);
515 ecryptfs_lower_offset_for_extent(
516 &offset
, ((((loff_t
)page
->index
)
518 / crypt_stat
->extent_size
))
519 + extent_offset
), crypt_stat
);
520 rc
= ecryptfs_write_lower(ecryptfs_inode
, enc_extent_virt
,
521 offset
, crypt_stat
->extent_size
);
523 ecryptfs_printk(KERN_ERR
, "Error attempting "
524 "to write lower page; rc = [%d]"
530 kfree(enc_extent_virt
);
534 static int ecryptfs_decrypt_extent(struct page
*page
,
535 struct ecryptfs_crypt_stat
*crypt_stat
,
536 struct page
*enc_extent_page
,
537 unsigned long extent_offset
)
540 char extent_iv
[ECRYPTFS_MAX_IV_BYTES
];
543 extent_base
= (((loff_t
)page
->index
)
544 * (PAGE_CACHE_SIZE
/ crypt_stat
->extent_size
));
545 rc
= ecryptfs_derive_iv(extent_iv
, crypt_stat
,
546 (extent_base
+ extent_offset
));
548 ecryptfs_printk(KERN_ERR
, "Error attempting to "
549 "derive IV for extent [0x%.16x]; "
550 "rc = [%d]\n", (extent_base
+ extent_offset
),
554 if (unlikely(ecryptfs_verbosity
> 0)) {
555 ecryptfs_printk(KERN_DEBUG
, "Decrypting extent "
557 ecryptfs_dump_hex(extent_iv
, crypt_stat
->iv_bytes
);
558 ecryptfs_printk(KERN_DEBUG
, "First 8 bytes before "
560 ecryptfs_dump_hex((char *)
561 (page_address(enc_extent_page
)
562 + (extent_offset
* crypt_stat
->extent_size
)),
565 rc
= ecryptfs_decrypt_page_offset(crypt_stat
, page
,
567 * crypt_stat
->extent_size
),
569 crypt_stat
->extent_size
, extent_iv
);
571 printk(KERN_ERR
"%s: Error attempting to decrypt to page with "
572 "page->index = [%ld], extent_offset = [%ld]; "
573 "rc = [%d]\n", __func__
, page
->index
, extent_offset
,
578 if (unlikely(ecryptfs_verbosity
> 0)) {
579 ecryptfs_printk(KERN_DEBUG
, "Decrypt extent [0x%.16x]; "
580 "rc = [%d]\n", (extent_base
+ extent_offset
),
582 ecryptfs_printk(KERN_DEBUG
, "First 8 bytes after "
584 ecryptfs_dump_hex((char *)(page_address(page
)
586 * crypt_stat
->extent_size
)), 8);
593 * ecryptfs_decrypt_page
594 * @page: Page mapped from the eCryptfs inode for the file; data read
595 * and decrypted from the lower file will be written into this
598 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
599 * that eCryptfs pages may straddle the lower pages -- for instance,
600 * if the file was created on a machine with an 8K page size
601 * (resulting in an 8K header), and then the file is copied onto a
602 * host with a 32K page size, then when reading page 0 of the eCryptfs
603 * file, 24K of page 0 of the lower file will be read and decrypted,
604 * and then 8K of page 1 of the lower file will be read and decrypted.
606 * Returns zero on success; negative on error
608 int ecryptfs_decrypt_page(struct page
*page
)
610 struct inode
*ecryptfs_inode
;
611 struct ecryptfs_crypt_stat
*crypt_stat
;
612 char *enc_extent_virt
= NULL
;
613 struct page
*enc_extent_page
;
614 unsigned long extent_offset
;
617 ecryptfs_inode
= page
->mapping
->host
;
619 &(ecryptfs_inode_to_private(ecryptfs_inode
)->crypt_stat
);
620 if (!(crypt_stat
->flags
& ECRYPTFS_ENCRYPTED
)) {
621 rc
= ecryptfs_read_lower_page_segment(page
, page
->index
, 0,
625 printk(KERN_ERR
"%s: Error attempting to copy "
626 "page at index [%ld]\n", __func__
,
630 enc_extent_virt
= kmalloc(PAGE_CACHE_SIZE
, GFP_USER
);
631 if (!enc_extent_virt
) {
633 ecryptfs_printk(KERN_ERR
, "Error allocating memory for "
634 "encrypted extent\n");
637 enc_extent_page
= virt_to_page(enc_extent_virt
);
638 for (extent_offset
= 0;
639 extent_offset
< (PAGE_CACHE_SIZE
/ crypt_stat
->extent_size
);
643 ecryptfs_lower_offset_for_extent(
644 &offset
, ((page
->index
* (PAGE_CACHE_SIZE
645 / crypt_stat
->extent_size
))
646 + extent_offset
), crypt_stat
);
647 rc
= ecryptfs_read_lower(enc_extent_virt
, offset
,
648 crypt_stat
->extent_size
,
651 ecryptfs_printk(KERN_ERR
, "Error attempting "
652 "to read lower page; rc = [%d]"
656 rc
= ecryptfs_decrypt_extent(page
, crypt_stat
, enc_extent_page
,
659 printk(KERN_ERR
"%s: Error encrypting extent; "
660 "rc = [%d]\n", __func__
, rc
);
665 kfree(enc_extent_virt
);
670 * decrypt_scatterlist
671 * @crypt_stat: Cryptographic context
672 * @dest_sg: The destination scatterlist to decrypt into
673 * @src_sg: The source scatterlist to decrypt from
674 * @size: The number of bytes to decrypt
675 * @iv: The initialization vector to use for the decryption
677 * Returns the number of bytes decrypted; negative value on error
679 static int decrypt_scatterlist(struct ecryptfs_crypt_stat
*crypt_stat
,
680 struct scatterlist
*dest_sg
,
681 struct scatterlist
*src_sg
, int size
,
684 struct blkcipher_desc desc
= {
685 .tfm
= crypt_stat
->tfm
,
687 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
691 /* Consider doing this once, when the file is opened */
692 mutex_lock(&crypt_stat
->cs_tfm_mutex
);
693 rc
= crypto_blkcipher_setkey(crypt_stat
->tfm
, crypt_stat
->key
,
694 crypt_stat
->key_size
);
696 ecryptfs_printk(KERN_ERR
, "Error setting key; rc = [%d]\n",
698 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
702 ecryptfs_printk(KERN_DEBUG
, "Decrypting [%d] bytes.\n", size
);
703 rc
= crypto_blkcipher_decrypt_iv(&desc
, dest_sg
, src_sg
, size
);
704 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
706 ecryptfs_printk(KERN_ERR
, "Error decrypting; rc = [%d]\n",
716 * ecryptfs_encrypt_page_offset
717 * @crypt_stat: The cryptographic context
718 * @dst_page: The page to encrypt into
719 * @dst_offset: The offset in the page to encrypt into
720 * @src_page: The page to encrypt from
721 * @src_offset: The offset in the page to encrypt from
722 * @size: The number of bytes to encrypt
723 * @iv: The initialization vector to use for the encryption
725 * Returns the number of bytes encrypted
728 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat
*crypt_stat
,
729 struct page
*dst_page
, int dst_offset
,
730 struct page
*src_page
, int src_offset
, int size
,
733 struct scatterlist src_sg
, dst_sg
;
735 sg_init_table(&src_sg
, 1);
736 sg_init_table(&dst_sg
, 1);
738 sg_set_page(&src_sg
, src_page
, size
, src_offset
);
739 sg_set_page(&dst_sg
, dst_page
, size
, dst_offset
);
740 return encrypt_scatterlist(crypt_stat
, &dst_sg
, &src_sg
, size
, iv
);
744 * ecryptfs_decrypt_page_offset
745 * @crypt_stat: The cryptographic context
746 * @dst_page: The page to decrypt into
747 * @dst_offset: The offset in the page to decrypt into
748 * @src_page: The page to decrypt from
749 * @src_offset: The offset in the page to decrypt from
750 * @size: The number of bytes to decrypt
751 * @iv: The initialization vector to use for the decryption
753 * Returns the number of bytes decrypted
756 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat
*crypt_stat
,
757 struct page
*dst_page
, int dst_offset
,
758 struct page
*src_page
, int src_offset
, int size
,
761 struct scatterlist src_sg
, dst_sg
;
763 sg_init_table(&src_sg
, 1);
764 sg_set_page(&src_sg
, src_page
, size
, src_offset
);
766 sg_init_table(&dst_sg
, 1);
767 sg_set_page(&dst_sg
, dst_page
, size
, dst_offset
);
769 return decrypt_scatterlist(crypt_stat
, &dst_sg
, &src_sg
, size
, iv
);
772 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
775 * ecryptfs_init_crypt_ctx
776 * @crypt_stat: Uninitilized crypt stats structure
778 * Initialize the crypto context.
780 * TODO: Performance: Keep a cache of initialized cipher contexts;
781 * only init if needed
783 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat
*crypt_stat
)
788 if (!crypt_stat
->cipher
) {
789 ecryptfs_printk(KERN_ERR
, "No cipher specified\n");
792 ecryptfs_printk(KERN_DEBUG
,
793 "Initializing cipher [%s]; strlen = [%d]; "
794 "key_size_bits = [%d]\n",
795 crypt_stat
->cipher
, (int)strlen(crypt_stat
->cipher
),
796 crypt_stat
->key_size
<< 3);
797 if (crypt_stat
->tfm
) {
801 mutex_lock(&crypt_stat
->cs_tfm_mutex
);
802 rc
= ecryptfs_crypto_api_algify_cipher_name(&full_alg_name
,
803 crypt_stat
->cipher
, "cbc");
806 crypt_stat
->tfm
= crypto_alloc_blkcipher(full_alg_name
, 0,
808 kfree(full_alg_name
);
809 if (IS_ERR(crypt_stat
->tfm
)) {
810 rc
= PTR_ERR(crypt_stat
->tfm
);
811 ecryptfs_printk(KERN_ERR
, "cryptfs: init_crypt_ctx(): "
812 "Error initializing cipher [%s]\n",
816 crypto_blkcipher_set_flags(crypt_stat
->tfm
, CRYPTO_TFM_REQ_WEAK_KEY
);
819 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
824 static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat
*crypt_stat
)
828 crypt_stat
->extent_mask
= 0xFFFFFFFF;
829 crypt_stat
->extent_shift
= 0;
830 if (crypt_stat
->extent_size
== 0)
832 extent_size_tmp
= crypt_stat
->extent_size
;
833 while ((extent_size_tmp
& 0x01) == 0) {
834 extent_size_tmp
>>= 1;
835 crypt_stat
->extent_mask
<<= 1;
836 crypt_stat
->extent_shift
++;
840 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat
*crypt_stat
)
842 /* Default values; may be overwritten as we are parsing the
844 crypt_stat
->extent_size
= ECRYPTFS_DEFAULT_EXTENT_SIZE
;
845 set_extent_mask_and_shift(crypt_stat
);
846 crypt_stat
->iv_bytes
= ECRYPTFS_DEFAULT_IV_BYTES
;
847 if (crypt_stat
->flags
& ECRYPTFS_METADATA_IN_XATTR
)
848 crypt_stat
->num_header_bytes_at_front
= 0;
850 if (PAGE_CACHE_SIZE
<= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
)
851 crypt_stat
->num_header_bytes_at_front
=
852 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
;
854 crypt_stat
->num_header_bytes_at_front
= PAGE_CACHE_SIZE
;
859 * ecryptfs_compute_root_iv
862 * On error, sets the root IV to all 0's.
864 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat
*crypt_stat
)
867 char dst
[MD5_DIGEST_SIZE
];
869 BUG_ON(crypt_stat
->iv_bytes
> MD5_DIGEST_SIZE
);
870 BUG_ON(crypt_stat
->iv_bytes
<= 0);
871 if (!(crypt_stat
->flags
& ECRYPTFS_KEY_VALID
)) {
873 ecryptfs_printk(KERN_WARNING
, "Session key not valid; "
874 "cannot generate root IV\n");
877 rc
= ecryptfs_calculate_md5(dst
, crypt_stat
, crypt_stat
->key
,
878 crypt_stat
->key_size
);
880 ecryptfs_printk(KERN_WARNING
, "Error attempting to compute "
881 "MD5 while generating root IV\n");
884 memcpy(crypt_stat
->root_iv
, dst
, crypt_stat
->iv_bytes
);
887 memset(crypt_stat
->root_iv
, 0, crypt_stat
->iv_bytes
);
888 crypt_stat
->flags
|= ECRYPTFS_SECURITY_WARNING
;
893 static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat
*crypt_stat
)
895 get_random_bytes(crypt_stat
->key
, crypt_stat
->key_size
);
896 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
897 ecryptfs_compute_root_iv(crypt_stat
);
898 if (unlikely(ecryptfs_verbosity
> 0)) {
899 ecryptfs_printk(KERN_DEBUG
, "Generated new session key:\n");
900 ecryptfs_dump_hex(crypt_stat
->key
,
901 crypt_stat
->key_size
);
906 * ecryptfs_copy_mount_wide_flags_to_inode_flags
907 * @crypt_stat: The inode's cryptographic context
908 * @mount_crypt_stat: The mount point's cryptographic context
910 * This function propagates the mount-wide flags to individual inode
913 static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
914 struct ecryptfs_crypt_stat
*crypt_stat
,
915 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
)
917 if (mount_crypt_stat
->flags
& ECRYPTFS_XATTR_METADATA_ENABLED
)
918 crypt_stat
->flags
|= ECRYPTFS_METADATA_IN_XATTR
;
919 if (mount_crypt_stat
->flags
& ECRYPTFS_ENCRYPTED_VIEW_ENABLED
)
920 crypt_stat
->flags
|= ECRYPTFS_VIEW_AS_ENCRYPTED
;
923 static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
924 struct ecryptfs_crypt_stat
*crypt_stat
,
925 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
)
927 struct ecryptfs_global_auth_tok
*global_auth_tok
;
930 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
931 list_for_each_entry(global_auth_tok
,
932 &mount_crypt_stat
->global_auth_tok_list
,
933 mount_crypt_stat_list
) {
934 rc
= ecryptfs_add_keysig(crypt_stat
, global_auth_tok
->sig
);
936 printk(KERN_ERR
"Error adding keysig; rc = [%d]\n", rc
);
938 &mount_crypt_stat
->global_auth_tok_list_mutex
);
942 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
948 * ecryptfs_set_default_crypt_stat_vals
949 * @crypt_stat: The inode's cryptographic context
950 * @mount_crypt_stat: The mount point's cryptographic context
952 * Default values in the event that policy does not override them.
954 static void ecryptfs_set_default_crypt_stat_vals(
955 struct ecryptfs_crypt_stat
*crypt_stat
,
956 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
)
958 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat
,
960 ecryptfs_set_default_sizes(crypt_stat
);
961 strcpy(crypt_stat
->cipher
, ECRYPTFS_DEFAULT_CIPHER
);
962 crypt_stat
->key_size
= ECRYPTFS_DEFAULT_KEY_BYTES
;
963 crypt_stat
->flags
&= ~(ECRYPTFS_KEY_VALID
);
964 crypt_stat
->file_version
= ECRYPTFS_FILE_VERSION
;
965 crypt_stat
->mount_crypt_stat
= mount_crypt_stat
;
969 * ecryptfs_new_file_context
970 * @ecryptfs_dentry: The eCryptfs dentry
972 * If the crypto context for the file has not yet been established,
973 * this is where we do that. Establishing a new crypto context
974 * involves the following decisions:
975 * - What cipher to use?
976 * - What set of authentication tokens to use?
977 * Here we just worry about getting enough information into the
978 * authentication tokens so that we know that they are available.
979 * We associate the available authentication tokens with the new file
980 * via the set of signatures in the crypt_stat struct. Later, when
981 * the headers are actually written out, we may again defer to
982 * userspace to perform the encryption of the session key; for the
983 * foreseeable future, this will be the case with public key packets.
985 * Returns zero on success; non-zero otherwise
987 int ecryptfs_new_file_context(struct dentry
*ecryptfs_dentry
)
989 struct ecryptfs_crypt_stat
*crypt_stat
=
990 &ecryptfs_inode_to_private(ecryptfs_dentry
->d_inode
)->crypt_stat
;
991 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
992 &ecryptfs_superblock_to_private(
993 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
997 ecryptfs_set_default_crypt_stat_vals(crypt_stat
, mount_crypt_stat
);
998 crypt_stat
->flags
|= (ECRYPTFS_ENCRYPTED
| ECRYPTFS_KEY_VALID
);
999 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat
,
1001 rc
= ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat
,
1004 printk(KERN_ERR
"Error attempting to copy mount-wide key sigs "
1005 "to the inode key sigs; rc = [%d]\n", rc
);
1009 strlen(mount_crypt_stat
->global_default_cipher_name
);
1010 memcpy(crypt_stat
->cipher
,
1011 mount_crypt_stat
->global_default_cipher_name
,
1013 crypt_stat
->cipher
[cipher_name_len
] = '\0';
1014 crypt_stat
->key_size
=
1015 mount_crypt_stat
->global_default_cipher_key_size
;
1016 ecryptfs_generate_new_key(crypt_stat
);
1017 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1019 ecryptfs_printk(KERN_ERR
, "Error initializing cryptographic "
1020 "context for cipher [%s]: rc = [%d]\n",
1021 crypt_stat
->cipher
, rc
);
1027 * contains_ecryptfs_marker - check for the ecryptfs marker
1028 * @data: The data block in which to check
1030 * Returns one if marker found; zero if not found
1032 static int contains_ecryptfs_marker(char *data
)
1036 m_1
= get_unaligned_be32(data
);
1037 m_2
= get_unaligned_be32(data
+ 4);
1038 if ((m_1
^ MAGIC_ECRYPTFS_MARKER
) == m_2
)
1040 ecryptfs_printk(KERN_DEBUG
, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1041 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1
, m_2
,
1042 MAGIC_ECRYPTFS_MARKER
);
1043 ecryptfs_printk(KERN_DEBUG
, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1044 "[0x%.8x]\n", (m_1
^ MAGIC_ECRYPTFS_MARKER
));
1048 struct ecryptfs_flag_map_elem
{
1053 /* Add support for additional flags by adding elements here. */
1054 static struct ecryptfs_flag_map_elem ecryptfs_flag_map
[] = {
1055 {0x00000001, ECRYPTFS_ENABLE_HMAC
},
1056 {0x00000002, ECRYPTFS_ENCRYPTED
},
1057 {0x00000004, ECRYPTFS_METADATA_IN_XATTR
}
1061 * ecryptfs_process_flags
1062 * @crypt_stat: The cryptographic context
1063 * @page_virt: Source data to be parsed
1064 * @bytes_read: Updated with the number of bytes read
1066 * Returns zero on success; non-zero if the flag set is invalid
1068 static int ecryptfs_process_flags(struct ecryptfs_crypt_stat
*crypt_stat
,
1069 char *page_virt
, int *bytes_read
)
1075 flags
= get_unaligned_be32(page_virt
);
1076 for (i
= 0; i
< ((sizeof(ecryptfs_flag_map
)
1077 / sizeof(struct ecryptfs_flag_map_elem
))); i
++)
1078 if (flags
& ecryptfs_flag_map
[i
].file_flag
) {
1079 crypt_stat
->flags
|= ecryptfs_flag_map
[i
].local_flag
;
1081 crypt_stat
->flags
&= ~(ecryptfs_flag_map
[i
].local_flag
);
1082 /* Version is in top 8 bits of the 32-bit flag vector */
1083 crypt_stat
->file_version
= ((flags
>> 24) & 0xFF);
1089 * write_ecryptfs_marker
1090 * @page_virt: The pointer to in a page to begin writing the marker
1091 * @written: Number of bytes written
1093 * Marker = 0x3c81b7f5
1095 static void write_ecryptfs_marker(char *page_virt
, size_t *written
)
1099 get_random_bytes(&m_1
, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
/ 2));
1100 m_2
= (m_1
^ MAGIC_ECRYPTFS_MARKER
);
1101 put_unaligned_be32(m_1
, page_virt
);
1102 page_virt
+= (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
/ 2);
1103 put_unaligned_be32(m_2
, page_virt
);
1104 (*written
) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
;
1108 write_ecryptfs_flags(char *page_virt
, struct ecryptfs_crypt_stat
*crypt_stat
,
1114 for (i
= 0; i
< ((sizeof(ecryptfs_flag_map
)
1115 / sizeof(struct ecryptfs_flag_map_elem
))); i
++)
1116 if (crypt_stat
->flags
& ecryptfs_flag_map
[i
].local_flag
)
1117 flags
|= ecryptfs_flag_map
[i
].file_flag
;
1118 /* Version is in top 8 bits of the 32-bit flag vector */
1119 flags
|= ((((u8
)crypt_stat
->file_version
) << 24) & 0xFF000000);
1120 put_unaligned_be32(flags
, page_virt
);
1124 struct ecryptfs_cipher_code_str_map_elem
{
1125 char cipher_str
[16];
1129 /* Add support for additional ciphers by adding elements here. The
1130 * cipher_code is whatever OpenPGP applicatoins use to identify the
1131 * ciphers. List in order of probability. */
1132 static struct ecryptfs_cipher_code_str_map_elem
1133 ecryptfs_cipher_code_str_map
[] = {
1134 {"aes",RFC2440_CIPHER_AES_128
},
1135 {"blowfish", RFC2440_CIPHER_BLOWFISH
},
1136 {"des3_ede", RFC2440_CIPHER_DES3_EDE
},
1137 {"cast5", RFC2440_CIPHER_CAST_5
},
1138 {"twofish", RFC2440_CIPHER_TWOFISH
},
1139 {"cast6", RFC2440_CIPHER_CAST_6
},
1140 {"aes", RFC2440_CIPHER_AES_192
},
1141 {"aes", RFC2440_CIPHER_AES_256
}
1145 * ecryptfs_code_for_cipher_string
1146 * @crypt_stat: The cryptographic context
1148 * Returns zero on no match, or the cipher code on match
1150 u8
ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat
*crypt_stat
)
1154 struct ecryptfs_cipher_code_str_map_elem
*map
=
1155 ecryptfs_cipher_code_str_map
;
1157 if (strcmp(crypt_stat
->cipher
, "aes") == 0) {
1158 switch (crypt_stat
->key_size
) {
1160 code
= RFC2440_CIPHER_AES_128
;
1163 code
= RFC2440_CIPHER_AES_192
;
1166 code
= RFC2440_CIPHER_AES_256
;
1169 for (i
= 0; i
< ARRAY_SIZE(ecryptfs_cipher_code_str_map
); i
++)
1170 if (strcmp(crypt_stat
->cipher
, map
[i
].cipher_str
) == 0){
1171 code
= map
[i
].cipher_code
;
1179 * ecryptfs_cipher_code_to_string
1180 * @str: Destination to write out the cipher name
1181 * @cipher_code: The code to convert to cipher name string
1183 * Returns zero on success
1185 int ecryptfs_cipher_code_to_string(char *str
, u8 cipher_code
)
1191 for (i
= 0; i
< ARRAY_SIZE(ecryptfs_cipher_code_str_map
); i
++)
1192 if (cipher_code
== ecryptfs_cipher_code_str_map
[i
].cipher_code
)
1193 strcpy(str
, ecryptfs_cipher_code_str_map
[i
].cipher_str
);
1194 if (str
[0] == '\0') {
1195 ecryptfs_printk(KERN_WARNING
, "Cipher code not recognized: "
1196 "[%d]\n", cipher_code
);
1202 int ecryptfs_read_and_validate_header_region(char *data
,
1203 struct inode
*ecryptfs_inode
)
1205 struct ecryptfs_crypt_stat
*crypt_stat
=
1206 &(ecryptfs_inode_to_private(ecryptfs_inode
)->crypt_stat
);
1209 rc
= ecryptfs_read_lower(data
, 0, crypt_stat
->extent_size
,
1212 printk(KERN_ERR
"%s: Error reading header region; rc = [%d]\n",
1216 if (!contains_ecryptfs_marker(data
+ ECRYPTFS_FILE_SIZE_BYTES
)) {
1218 ecryptfs_printk(KERN_DEBUG
, "Valid marker not found\n");
1225 ecryptfs_write_header_metadata(char *virt
,
1226 struct ecryptfs_crypt_stat
*crypt_stat
,
1229 u32 header_extent_size
;
1230 u16 num_header_extents_at_front
;
1232 header_extent_size
= (u32
)crypt_stat
->extent_size
;
1233 num_header_extents_at_front
=
1234 (u16
)(crypt_stat
->num_header_bytes_at_front
1235 / crypt_stat
->extent_size
);
1236 put_unaligned_be32(header_extent_size
, virt
);
1238 put_unaligned_be16(num_header_extents_at_front
, virt
);
1242 struct kmem_cache
*ecryptfs_header_cache_1
;
1243 struct kmem_cache
*ecryptfs_header_cache_2
;
1246 * ecryptfs_write_headers_virt
1247 * @page_virt: The virtual address to write the headers to
1248 * @size: Set to the number of bytes written by this function
1249 * @crypt_stat: The cryptographic context
1250 * @ecryptfs_dentry: The eCryptfs dentry
1255 * Octets 0-7: Unencrypted file size (big-endian)
1256 * Octets 8-15: eCryptfs special marker
1257 * Octets 16-19: Flags
1258 * Octet 16: File format version number (between 0 and 255)
1259 * Octets 17-18: Reserved
1260 * Octet 19: Bit 1 (lsb): Reserved
1262 * Bits 3-8: Reserved
1263 * Octets 20-23: Header extent size (big-endian)
1264 * Octets 24-25: Number of header extents at front of file
1266 * Octet 26: Begin RFC 2440 authentication token packet set
1268 * Lower data (CBC encrypted)
1270 * Lower data (CBC encrypted)
1273 * Returns zero on success
1275 static int ecryptfs_write_headers_virt(char *page_virt
, size_t *size
,
1276 struct ecryptfs_crypt_stat
*crypt_stat
,
1277 struct dentry
*ecryptfs_dentry
)
1283 offset
= ECRYPTFS_FILE_SIZE_BYTES
;
1284 write_ecryptfs_marker((page_virt
+ offset
), &written
);
1286 write_ecryptfs_flags((page_virt
+ offset
), crypt_stat
, &written
);
1288 ecryptfs_write_header_metadata((page_virt
+ offset
), crypt_stat
,
1291 rc
= ecryptfs_generate_key_packet_set((page_virt
+ offset
), crypt_stat
,
1292 ecryptfs_dentry
, &written
,
1293 PAGE_CACHE_SIZE
- offset
);
1295 ecryptfs_printk(KERN_WARNING
, "Error generating key packet "
1296 "set; rc = [%d]\n", rc
);
1305 ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat
*crypt_stat
,
1306 struct dentry
*ecryptfs_dentry
,
1311 rc
= ecryptfs_write_lower(ecryptfs_dentry
->d_inode
, virt
,
1312 0, crypt_stat
->num_header_bytes_at_front
);
1314 printk(KERN_ERR
"%s: Error attempting to write header "
1315 "information to lower file; rc = [%d]\n", __func__
,
1321 ecryptfs_write_metadata_to_xattr(struct dentry
*ecryptfs_dentry
,
1322 struct ecryptfs_crypt_stat
*crypt_stat
,
1323 char *page_virt
, size_t size
)
1327 rc
= ecryptfs_setxattr(ecryptfs_dentry
, ECRYPTFS_XATTR_NAME
, page_virt
,
1333 * ecryptfs_write_metadata
1334 * @ecryptfs_dentry: The eCryptfs dentry
1336 * Write the file headers out. This will likely involve a userspace
1337 * callout, in which the session key is encrypted with one or more
1338 * public keys and/or the passphrase necessary to do the encryption is
1339 * retrieved via a prompt. Exactly what happens at this point should
1340 * be policy-dependent.
1342 * Returns zero on success; non-zero on error
1344 int ecryptfs_write_metadata(struct dentry
*ecryptfs_dentry
)
1346 struct ecryptfs_crypt_stat
*crypt_stat
=
1347 &ecryptfs_inode_to_private(ecryptfs_dentry
->d_inode
)->crypt_stat
;
1352 if (likely(crypt_stat
->flags
& ECRYPTFS_ENCRYPTED
)) {
1353 if (!(crypt_stat
->flags
& ECRYPTFS_KEY_VALID
)) {
1354 printk(KERN_ERR
"Key is invalid; bailing out\n");
1359 printk(KERN_WARNING
"%s: Encrypted flag not set\n",
1364 /* Released in this function */
1365 virt
= kzalloc(crypt_stat
->num_header_bytes_at_front
, GFP_KERNEL
);
1367 printk(KERN_ERR
"%s: Out of memory\n", __func__
);
1371 rc
= ecryptfs_write_headers_virt(virt
, &size
, crypt_stat
,
1374 printk(KERN_ERR
"%s: Error whilst writing headers; rc = [%d]\n",
1378 if (crypt_stat
->flags
& ECRYPTFS_METADATA_IN_XATTR
)
1379 rc
= ecryptfs_write_metadata_to_xattr(ecryptfs_dentry
,
1380 crypt_stat
, virt
, size
);
1382 rc
= ecryptfs_write_metadata_to_contents(crypt_stat
,
1383 ecryptfs_dentry
, virt
);
1385 printk(KERN_ERR
"%s: Error writing metadata out to lower file; "
1386 "rc = [%d]\n", __func__
, rc
);
1390 memset(virt
, 0, crypt_stat
->num_header_bytes_at_front
);
1396 #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1397 #define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1398 static int parse_header_metadata(struct ecryptfs_crypt_stat
*crypt_stat
,
1399 char *virt
, int *bytes_read
,
1400 int validate_header_size
)
1403 u32 header_extent_size
;
1404 u16 num_header_extents_at_front
;
1406 header_extent_size
= get_unaligned_be32(virt
);
1407 virt
+= sizeof(__be32
);
1408 num_header_extents_at_front
= get_unaligned_be16(virt
);
1409 crypt_stat
->num_header_bytes_at_front
=
1410 (((size_t)num_header_extents_at_front
1411 * (size_t)header_extent_size
));
1412 (*bytes_read
) = (sizeof(__be32
) + sizeof(__be16
));
1413 if ((validate_header_size
== ECRYPTFS_VALIDATE_HEADER_SIZE
)
1414 && (crypt_stat
->num_header_bytes_at_front
1415 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
)) {
1417 printk(KERN_WARNING
"Invalid header size: [%zd]\n",
1418 crypt_stat
->num_header_bytes_at_front
);
1424 * set_default_header_data
1425 * @crypt_stat: The cryptographic context
1427 * For version 0 file format; this function is only for backwards
1428 * compatibility for files created with the prior versions of
1431 static void set_default_header_data(struct ecryptfs_crypt_stat
*crypt_stat
)
1433 crypt_stat
->num_header_bytes_at_front
=
1434 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
;
1438 * ecryptfs_read_headers_virt
1439 * @page_virt: The virtual address into which to read the headers
1440 * @crypt_stat: The cryptographic context
1441 * @ecryptfs_dentry: The eCryptfs dentry
1442 * @validate_header_size: Whether to validate the header size while reading
1444 * Read/parse the header data. The header format is detailed in the
1445 * comment block for the ecryptfs_write_headers_virt() function.
1447 * Returns zero on success
1449 static int ecryptfs_read_headers_virt(char *page_virt
,
1450 struct ecryptfs_crypt_stat
*crypt_stat
,
1451 struct dentry
*ecryptfs_dentry
,
1452 int validate_header_size
)
1458 ecryptfs_set_default_sizes(crypt_stat
);
1459 crypt_stat
->mount_crypt_stat
= &ecryptfs_superblock_to_private(
1460 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
1461 offset
= ECRYPTFS_FILE_SIZE_BYTES
;
1462 rc
= contains_ecryptfs_marker(page_virt
+ offset
);
1467 offset
+= MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
;
1468 rc
= ecryptfs_process_flags(crypt_stat
, (page_virt
+ offset
),
1471 ecryptfs_printk(KERN_WARNING
, "Error processing flags\n");
1474 if (crypt_stat
->file_version
> ECRYPTFS_SUPPORTED_FILE_VERSION
) {
1475 ecryptfs_printk(KERN_WARNING
, "File version is [%d]; only "
1476 "file version [%d] is supported by this "
1477 "version of eCryptfs\n",
1478 crypt_stat
->file_version
,
1479 ECRYPTFS_SUPPORTED_FILE_VERSION
);
1483 offset
+= bytes_read
;
1484 if (crypt_stat
->file_version
>= 1) {
1485 rc
= parse_header_metadata(crypt_stat
, (page_virt
+ offset
),
1486 &bytes_read
, validate_header_size
);
1488 ecryptfs_printk(KERN_WARNING
, "Error reading header "
1489 "metadata; rc = [%d]\n", rc
);
1491 offset
+= bytes_read
;
1493 set_default_header_data(crypt_stat
);
1494 rc
= ecryptfs_parse_packet_set(crypt_stat
, (page_virt
+ offset
),
1501 * ecryptfs_read_xattr_region
1502 * @page_virt: The vitual address into which to read the xattr data
1503 * @ecryptfs_inode: The eCryptfs inode
1505 * Attempts to read the crypto metadata from the extended attribute
1506 * region of the lower file.
1508 * Returns zero on success; non-zero on error
1510 int ecryptfs_read_xattr_region(char *page_virt
, struct inode
*ecryptfs_inode
)
1512 struct dentry
*lower_dentry
=
1513 ecryptfs_inode_to_private(ecryptfs_inode
)->lower_file
->f_dentry
;
1517 size
= ecryptfs_getxattr_lower(lower_dentry
, ECRYPTFS_XATTR_NAME
,
1518 page_virt
, ECRYPTFS_DEFAULT_EXTENT_SIZE
);
1520 if (unlikely(ecryptfs_verbosity
> 0))
1521 printk(KERN_INFO
"Error attempting to read the [%s] "
1522 "xattr from the lower file; return value = "
1523 "[%zd]\n", ECRYPTFS_XATTR_NAME
, size
);
1531 int ecryptfs_read_and_validate_xattr_region(char *page_virt
,
1532 struct dentry
*ecryptfs_dentry
)
1536 rc
= ecryptfs_read_xattr_region(page_virt
, ecryptfs_dentry
->d_inode
);
1539 if (!contains_ecryptfs_marker(page_virt
+ ECRYPTFS_FILE_SIZE_BYTES
)) {
1540 printk(KERN_WARNING
"Valid data found in [%s] xattr, but "
1541 "the marker is invalid\n", ECRYPTFS_XATTR_NAME
);
1549 * ecryptfs_read_metadata
1551 * Common entry point for reading file metadata. From here, we could
1552 * retrieve the header information from the header region of the file,
1553 * the xattr region of the file, or some other repostory that is
1554 * stored separately from the file itself. The current implementation
1555 * supports retrieving the metadata information from the file contents
1556 * and from the xattr region.
1558 * Returns zero if valid headers found and parsed; non-zero otherwise
1560 int ecryptfs_read_metadata(struct dentry
*ecryptfs_dentry
)
1563 char *page_virt
= NULL
;
1564 struct inode
*ecryptfs_inode
= ecryptfs_dentry
->d_inode
;
1565 struct ecryptfs_crypt_stat
*crypt_stat
=
1566 &ecryptfs_inode_to_private(ecryptfs_inode
)->crypt_stat
;
1567 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1568 &ecryptfs_superblock_to_private(
1569 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
1571 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat
,
1573 /* Read the first page from the underlying file */
1574 page_virt
= kmem_cache_alloc(ecryptfs_header_cache_1
, GFP_USER
);
1577 printk(KERN_ERR
"%s: Unable to allocate page_virt\n",
1581 rc
= ecryptfs_read_lower(page_virt
, 0, crypt_stat
->extent_size
,
1584 rc
= ecryptfs_read_headers_virt(page_virt
, crypt_stat
,
1586 ECRYPTFS_VALIDATE_HEADER_SIZE
);
1588 rc
= ecryptfs_read_xattr_region(page_virt
, ecryptfs_inode
);
1590 printk(KERN_DEBUG
"Valid eCryptfs headers not found in "
1591 "file header region or xattr region\n");
1595 rc
= ecryptfs_read_headers_virt(page_virt
, crypt_stat
,
1597 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE
);
1599 printk(KERN_DEBUG
"Valid eCryptfs headers not found in "
1600 "file xattr region either\n");
1603 if (crypt_stat
->mount_crypt_stat
->flags
1604 & ECRYPTFS_XATTR_METADATA_ENABLED
) {
1605 crypt_stat
->flags
|= ECRYPTFS_METADATA_IN_XATTR
;
1607 printk(KERN_WARNING
"Attempt to access file with "
1608 "crypto metadata only in the extended attribute "
1609 "region, but eCryptfs was mounted without "
1610 "xattr support enabled. eCryptfs will not treat "
1611 "this like an encrypted file.\n");
1617 memset(page_virt
, 0, PAGE_CACHE_SIZE
);
1618 kmem_cache_free(ecryptfs_header_cache_1
, page_virt
);
1624 * ecryptfs_encode_filename - converts a plaintext file name to cipher text
1625 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
1626 * @name: The plaintext name
1627 * @length: The length of the plaintext
1628 * @encoded_name: The encypted name
1630 * Encrypts and encodes a filename into something that constitutes a
1631 * valid filename for a filesystem, with printable characters.
1633 * We assume that we have a properly initialized crypto context,
1634 * pointed to by crypt_stat->tfm.
1636 * TODO: Implement filename decoding and decryption here, in place of
1637 * memcpy. We are keeping the framework around for now to (1)
1638 * facilitate testing of the components needed to implement filename
1639 * encryption and (2) to provide a code base from which other
1640 * developers in the community can easily implement this feature.
1642 * Returns the length of encoded filename; negative if error
1645 ecryptfs_encode_filename(struct ecryptfs_crypt_stat
*crypt_stat
,
1646 const char *name
, int length
, char **encoded_name
)
1650 (*encoded_name
) = kmalloc(length
+ 2, GFP_KERNEL
);
1651 if (!(*encoded_name
)) {
1655 /* TODO: Filename encryption is a scheduled feature for a
1656 * future version of eCryptfs. This function is here only for
1657 * the purpose of providing a framework for other developers
1658 * to easily implement filename encryption. Hint: Replace this
1659 * memcpy() with a call to encrypt and encode the
1660 * filename, the set the length accordingly. */
1661 memcpy((void *)(*encoded_name
), (void *)name
, length
);
1662 (*encoded_name
)[length
] = '\0';
1669 * ecryptfs_decode_filename - converts the cipher text name to plaintext
1670 * @crypt_stat: The crypt_stat struct associated with the file
1671 * @name: The filename in cipher text
1672 * @length: The length of the cipher text name
1673 * @decrypted_name: The plaintext name
1675 * Decodes and decrypts the filename.
1677 * We assume that we have a properly initialized crypto context,
1678 * pointed to by crypt_stat->tfm.
1680 * TODO: Implement filename decoding and decryption here, in place of
1681 * memcpy. We are keeping the framework around for now to (1)
1682 * facilitate testing of the components needed to implement filename
1683 * encryption and (2) to provide a code base from which other
1684 * developers in the community can easily implement this feature.
1686 * Returns the length of decoded filename; negative if error
1689 ecryptfs_decode_filename(struct ecryptfs_crypt_stat
*crypt_stat
,
1690 const char *name
, int length
, char **decrypted_name
)
1694 (*decrypted_name
) = kmalloc(length
+ 2, GFP_KERNEL
);
1695 if (!(*decrypted_name
)) {
1699 /* TODO: Filename encryption is a scheduled feature for a
1700 * future version of eCryptfs. This function is here only for
1701 * the purpose of providing a framework for other developers
1702 * to easily implement filename encryption. Hint: Replace this
1703 * memcpy() with a call to decode and decrypt the
1704 * filename, the set the length accordingly. */
1705 memcpy((void *)(*decrypted_name
), (void *)name
, length
);
1706 (*decrypted_name
)[length
+ 1] = '\0'; /* Only for convenience
1707 * in printing out the
1716 * ecryptfs_process_key_cipher - Perform key cipher initialization.
1717 * @key_tfm: Crypto context for key material, set by this function
1718 * @cipher_name: Name of the cipher
1719 * @key_size: Size of the key in bytes
1721 * Returns zero on success. Any crypto_tfm structs allocated here
1722 * should be released by other functions, such as on a superblock put
1723 * event, regardless of whether this function succeeds for fails.
1726 ecryptfs_process_key_cipher(struct crypto_blkcipher
**key_tfm
,
1727 char *cipher_name
, size_t *key_size
)
1729 char dummy_key
[ECRYPTFS_MAX_KEY_BYTES
];
1730 char *full_alg_name
;
1734 if (*key_size
> ECRYPTFS_MAX_KEY_BYTES
) {
1736 printk(KERN_ERR
"Requested key size is [%Zd] bytes; maximum "
1737 "allowable is [%d]\n", *key_size
, ECRYPTFS_MAX_KEY_BYTES
);
1740 rc
= ecryptfs_crypto_api_algify_cipher_name(&full_alg_name
, cipher_name
,
1744 *key_tfm
= crypto_alloc_blkcipher(full_alg_name
, 0, CRYPTO_ALG_ASYNC
);
1745 kfree(full_alg_name
);
1746 if (IS_ERR(*key_tfm
)) {
1747 rc
= PTR_ERR(*key_tfm
);
1748 printk(KERN_ERR
"Unable to allocate crypto cipher with name "
1749 "[%s]; rc = [%d]\n", cipher_name
, rc
);
1752 crypto_blkcipher_set_flags(*key_tfm
, CRYPTO_TFM_REQ_WEAK_KEY
);
1753 if (*key_size
== 0) {
1754 struct blkcipher_alg
*alg
= crypto_blkcipher_alg(*key_tfm
);
1756 *key_size
= alg
->max_keysize
;
1758 get_random_bytes(dummy_key
, *key_size
);
1759 rc
= crypto_blkcipher_setkey(*key_tfm
, dummy_key
, *key_size
);
1761 printk(KERN_ERR
"Error attempting to set key of size [%Zd] for "
1762 "cipher [%s]; rc = [%d]\n", *key_size
, cipher_name
, rc
);
1770 struct kmem_cache
*ecryptfs_key_tfm_cache
;
1771 static struct list_head key_tfm_list
;
1772 struct mutex key_tfm_list_mutex
;
1774 int ecryptfs_init_crypto(void)
1776 mutex_init(&key_tfm_list_mutex
);
1777 INIT_LIST_HEAD(&key_tfm_list
);
1782 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1784 * Called only at module unload time
1786 int ecryptfs_destroy_crypto(void)
1788 struct ecryptfs_key_tfm
*key_tfm
, *key_tfm_tmp
;
1790 mutex_lock(&key_tfm_list_mutex
);
1791 list_for_each_entry_safe(key_tfm
, key_tfm_tmp
, &key_tfm_list
,
1793 list_del(&key_tfm
->key_tfm_list
);
1794 if (key_tfm
->key_tfm
)
1795 crypto_free_blkcipher(key_tfm
->key_tfm
);
1796 kmem_cache_free(ecryptfs_key_tfm_cache
, key_tfm
);
1798 mutex_unlock(&key_tfm_list_mutex
);
1803 ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm
**key_tfm
, char *cipher_name
,
1806 struct ecryptfs_key_tfm
*tmp_tfm
;
1809 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex
));
1811 tmp_tfm
= kmem_cache_alloc(ecryptfs_key_tfm_cache
, GFP_KERNEL
);
1812 if (key_tfm
!= NULL
)
1813 (*key_tfm
) = tmp_tfm
;
1816 printk(KERN_ERR
"Error attempting to allocate from "
1817 "ecryptfs_key_tfm_cache\n");
1820 mutex_init(&tmp_tfm
->key_tfm_mutex
);
1821 strncpy(tmp_tfm
->cipher_name
, cipher_name
,
1822 ECRYPTFS_MAX_CIPHER_NAME_SIZE
);
1823 tmp_tfm
->cipher_name
[ECRYPTFS_MAX_CIPHER_NAME_SIZE
] = '\0';
1824 tmp_tfm
->key_size
= key_size
;
1825 rc
= ecryptfs_process_key_cipher(&tmp_tfm
->key_tfm
,
1826 tmp_tfm
->cipher_name
,
1827 &tmp_tfm
->key_size
);
1829 printk(KERN_ERR
"Error attempting to initialize key TFM "
1830 "cipher with name = [%s]; rc = [%d]\n",
1831 tmp_tfm
->cipher_name
, rc
);
1832 kmem_cache_free(ecryptfs_key_tfm_cache
, tmp_tfm
);
1833 if (key_tfm
!= NULL
)
1837 list_add(&tmp_tfm
->key_tfm_list
, &key_tfm_list
);
1843 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1844 * @cipher_name: the name of the cipher to search for
1845 * @key_tfm: set to corresponding tfm if found
1847 * Searches for cached key_tfm matching @cipher_name
1848 * Must be called with &key_tfm_list_mutex held
1849 * Returns 1 if found, with @key_tfm set
1850 * Returns 0 if not found, with @key_tfm set to NULL
1852 int ecryptfs_tfm_exists(char *cipher_name
, struct ecryptfs_key_tfm
**key_tfm
)
1854 struct ecryptfs_key_tfm
*tmp_key_tfm
;
1856 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex
));
1858 list_for_each_entry(tmp_key_tfm
, &key_tfm_list
, key_tfm_list
) {
1859 if (strcmp(tmp_key_tfm
->cipher_name
, cipher_name
) == 0) {
1861 (*key_tfm
) = tmp_key_tfm
;
1871 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1873 * @tfm: set to cached tfm found, or new tfm created
1874 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1875 * @cipher_name: the name of the cipher to search for and/or add
1877 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1878 * Searches for cached item first, and creates new if not found.
1879 * Returns 0 on success, non-zero if adding new cipher failed
1881 int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher
**tfm
,
1882 struct mutex
**tfm_mutex
,
1885 struct ecryptfs_key_tfm
*key_tfm
;
1889 (*tfm_mutex
) = NULL
;
1891 mutex_lock(&key_tfm_list_mutex
);
1892 if (!ecryptfs_tfm_exists(cipher_name
, &key_tfm
)) {
1893 rc
= ecryptfs_add_new_key_tfm(&key_tfm
, cipher_name
, 0);
1895 printk(KERN_ERR
"Error adding new key_tfm to list; "
1900 (*tfm
) = key_tfm
->key_tfm
;
1901 (*tfm_mutex
) = &key_tfm
->key_tfm_mutex
;
1903 mutex_unlock(&key_tfm_list_mutex
);