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 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
;
479 struct page
*enc_extent_page
= NULL
;
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_page
= alloc_page(GFP_USER
);
496 if (!enc_extent_page
) {
498 ecryptfs_printk(KERN_ERR
, "Error allocating memory for "
499 "encrypted extent\n");
502 enc_extent_virt
= kmap(enc_extent_page
);
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 if (enc_extent_page
) {
531 kunmap(enc_extent_page
);
532 __free_page(enc_extent_page
);
537 static int ecryptfs_decrypt_extent(struct page
*page
,
538 struct ecryptfs_crypt_stat
*crypt_stat
,
539 struct page
*enc_extent_page
,
540 unsigned long extent_offset
)
543 char extent_iv
[ECRYPTFS_MAX_IV_BYTES
];
546 extent_base
= (((loff_t
)page
->index
)
547 * (PAGE_CACHE_SIZE
/ crypt_stat
->extent_size
));
548 rc
= ecryptfs_derive_iv(extent_iv
, crypt_stat
,
549 (extent_base
+ extent_offset
));
551 ecryptfs_printk(KERN_ERR
, "Error attempting to "
552 "derive IV for extent [0x%.16x]; "
553 "rc = [%d]\n", (extent_base
+ extent_offset
),
557 if (unlikely(ecryptfs_verbosity
> 0)) {
558 ecryptfs_printk(KERN_DEBUG
, "Decrypting extent "
560 ecryptfs_dump_hex(extent_iv
, crypt_stat
->iv_bytes
);
561 ecryptfs_printk(KERN_DEBUG
, "First 8 bytes before "
563 ecryptfs_dump_hex((char *)
564 (page_address(enc_extent_page
)
565 + (extent_offset
* crypt_stat
->extent_size
)),
568 rc
= ecryptfs_decrypt_page_offset(crypt_stat
, page
,
570 * crypt_stat
->extent_size
),
572 crypt_stat
->extent_size
, extent_iv
);
574 printk(KERN_ERR
"%s: Error attempting to decrypt to page with "
575 "page->index = [%ld], extent_offset = [%ld]; "
576 "rc = [%d]\n", __func__
, page
->index
, extent_offset
,
581 if (unlikely(ecryptfs_verbosity
> 0)) {
582 ecryptfs_printk(KERN_DEBUG
, "Decrypt extent [0x%.16x]; "
583 "rc = [%d]\n", (extent_base
+ extent_offset
),
585 ecryptfs_printk(KERN_DEBUG
, "First 8 bytes after "
587 ecryptfs_dump_hex((char *)(page_address(page
)
589 * crypt_stat
->extent_size
)), 8);
596 * ecryptfs_decrypt_page
597 * @page: Page mapped from the eCryptfs inode for the file; data read
598 * and decrypted from the lower file will be written into this
601 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
602 * that eCryptfs pages may straddle the lower pages -- for instance,
603 * if the file was created on a machine with an 8K page size
604 * (resulting in an 8K header), and then the file is copied onto a
605 * host with a 32K page size, then when reading page 0 of the eCryptfs
606 * file, 24K of page 0 of the lower file will be read and decrypted,
607 * and then 8K of page 1 of the lower file will be read and decrypted.
609 * Returns zero on success; negative on error
611 int ecryptfs_decrypt_page(struct page
*page
)
613 struct inode
*ecryptfs_inode
;
614 struct ecryptfs_crypt_stat
*crypt_stat
;
615 char *enc_extent_virt
;
616 struct page
*enc_extent_page
= NULL
;
617 unsigned long extent_offset
;
620 ecryptfs_inode
= page
->mapping
->host
;
622 &(ecryptfs_inode_to_private(ecryptfs_inode
)->crypt_stat
);
623 if (!(crypt_stat
->flags
& ECRYPTFS_ENCRYPTED
)) {
624 rc
= ecryptfs_read_lower_page_segment(page
, page
->index
, 0,
628 printk(KERN_ERR
"%s: Error attempting to copy "
629 "page at index [%ld]\n", __func__
,
633 enc_extent_page
= alloc_page(GFP_USER
);
634 if (!enc_extent_page
) {
636 ecryptfs_printk(KERN_ERR
, "Error allocating memory for "
637 "encrypted extent\n");
640 enc_extent_virt
= kmap(enc_extent_page
);
641 for (extent_offset
= 0;
642 extent_offset
< (PAGE_CACHE_SIZE
/ crypt_stat
->extent_size
);
646 ecryptfs_lower_offset_for_extent(
647 &offset
, ((page
->index
* (PAGE_CACHE_SIZE
648 / crypt_stat
->extent_size
))
649 + extent_offset
), crypt_stat
);
650 rc
= ecryptfs_read_lower(enc_extent_virt
, offset
,
651 crypt_stat
->extent_size
,
654 ecryptfs_printk(KERN_ERR
, "Error attempting "
655 "to read lower page; rc = [%d]"
659 rc
= ecryptfs_decrypt_extent(page
, crypt_stat
, enc_extent_page
,
662 printk(KERN_ERR
"%s: Error encrypting extent; "
663 "rc = [%d]\n", __func__
, rc
);
668 if (enc_extent_page
) {
669 kunmap(enc_extent_page
);
670 __free_page(enc_extent_page
);
676 * decrypt_scatterlist
677 * @crypt_stat: Cryptographic context
678 * @dest_sg: The destination scatterlist to decrypt into
679 * @src_sg: The source scatterlist to decrypt from
680 * @size: The number of bytes to decrypt
681 * @iv: The initialization vector to use for the decryption
683 * Returns the number of bytes decrypted; negative value on error
685 static int decrypt_scatterlist(struct ecryptfs_crypt_stat
*crypt_stat
,
686 struct scatterlist
*dest_sg
,
687 struct scatterlist
*src_sg
, int size
,
690 struct blkcipher_desc desc
= {
691 .tfm
= crypt_stat
->tfm
,
693 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
697 /* Consider doing this once, when the file is opened */
698 mutex_lock(&crypt_stat
->cs_tfm_mutex
);
699 rc
= crypto_blkcipher_setkey(crypt_stat
->tfm
, crypt_stat
->key
,
700 crypt_stat
->key_size
);
702 ecryptfs_printk(KERN_ERR
, "Error setting key; rc = [%d]\n",
704 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
708 ecryptfs_printk(KERN_DEBUG
, "Decrypting [%d] bytes.\n", size
);
709 rc
= crypto_blkcipher_decrypt_iv(&desc
, dest_sg
, src_sg
, size
);
710 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
712 ecryptfs_printk(KERN_ERR
, "Error decrypting; rc = [%d]\n",
722 * ecryptfs_encrypt_page_offset
723 * @crypt_stat: The cryptographic context
724 * @dst_page: The page to encrypt into
725 * @dst_offset: The offset in the page to encrypt into
726 * @src_page: The page to encrypt from
727 * @src_offset: The offset in the page to encrypt from
728 * @size: The number of bytes to encrypt
729 * @iv: The initialization vector to use for the encryption
731 * Returns the number of bytes encrypted
734 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat
*crypt_stat
,
735 struct page
*dst_page
, int dst_offset
,
736 struct page
*src_page
, int src_offset
, int size
,
739 struct scatterlist src_sg
, dst_sg
;
741 sg_init_table(&src_sg
, 1);
742 sg_init_table(&dst_sg
, 1);
744 sg_set_page(&src_sg
, src_page
, size
, src_offset
);
745 sg_set_page(&dst_sg
, dst_page
, size
, dst_offset
);
746 return encrypt_scatterlist(crypt_stat
, &dst_sg
, &src_sg
, size
, iv
);
750 * ecryptfs_decrypt_page_offset
751 * @crypt_stat: The cryptographic context
752 * @dst_page: The page to decrypt into
753 * @dst_offset: The offset in the page to decrypt into
754 * @src_page: The page to decrypt from
755 * @src_offset: The offset in the page to decrypt from
756 * @size: The number of bytes to decrypt
757 * @iv: The initialization vector to use for the decryption
759 * Returns the number of bytes decrypted
762 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat
*crypt_stat
,
763 struct page
*dst_page
, int dst_offset
,
764 struct page
*src_page
, int src_offset
, int size
,
767 struct scatterlist src_sg
, dst_sg
;
769 sg_init_table(&src_sg
, 1);
770 sg_set_page(&src_sg
, src_page
, size
, src_offset
);
772 sg_init_table(&dst_sg
, 1);
773 sg_set_page(&dst_sg
, dst_page
, size
, dst_offset
);
775 return decrypt_scatterlist(crypt_stat
, &dst_sg
, &src_sg
, size
, iv
);
778 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
781 * ecryptfs_init_crypt_ctx
782 * @crypt_stat: Uninitilized crypt stats structure
784 * Initialize the crypto context.
786 * TODO: Performance: Keep a cache of initialized cipher contexts;
787 * only init if needed
789 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat
*crypt_stat
)
794 if (!crypt_stat
->cipher
) {
795 ecryptfs_printk(KERN_ERR
, "No cipher specified\n");
798 ecryptfs_printk(KERN_DEBUG
,
799 "Initializing cipher [%s]; strlen = [%d]; "
800 "key_size_bits = [%d]\n",
801 crypt_stat
->cipher
, (int)strlen(crypt_stat
->cipher
),
802 crypt_stat
->key_size
<< 3);
803 if (crypt_stat
->tfm
) {
807 mutex_lock(&crypt_stat
->cs_tfm_mutex
);
808 rc
= ecryptfs_crypto_api_algify_cipher_name(&full_alg_name
,
809 crypt_stat
->cipher
, "cbc");
812 crypt_stat
->tfm
= crypto_alloc_blkcipher(full_alg_name
, 0,
814 kfree(full_alg_name
);
815 if (IS_ERR(crypt_stat
->tfm
)) {
816 rc
= PTR_ERR(crypt_stat
->tfm
);
817 ecryptfs_printk(KERN_ERR
, "cryptfs: init_crypt_ctx(): "
818 "Error initializing cipher [%s]\n",
822 crypto_blkcipher_set_flags(crypt_stat
->tfm
, CRYPTO_TFM_REQ_WEAK_KEY
);
825 mutex_unlock(&crypt_stat
->cs_tfm_mutex
);
830 static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat
*crypt_stat
)
834 crypt_stat
->extent_mask
= 0xFFFFFFFF;
835 crypt_stat
->extent_shift
= 0;
836 if (crypt_stat
->extent_size
== 0)
838 extent_size_tmp
= crypt_stat
->extent_size
;
839 while ((extent_size_tmp
& 0x01) == 0) {
840 extent_size_tmp
>>= 1;
841 crypt_stat
->extent_mask
<<= 1;
842 crypt_stat
->extent_shift
++;
846 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat
*crypt_stat
)
848 /* Default values; may be overwritten as we are parsing the
850 crypt_stat
->extent_size
= ECRYPTFS_DEFAULT_EXTENT_SIZE
;
851 set_extent_mask_and_shift(crypt_stat
);
852 crypt_stat
->iv_bytes
= ECRYPTFS_DEFAULT_IV_BYTES
;
853 if (crypt_stat
->flags
& ECRYPTFS_METADATA_IN_XATTR
)
854 crypt_stat
->num_header_bytes_at_front
= 0;
856 if (PAGE_CACHE_SIZE
<= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
)
857 crypt_stat
->num_header_bytes_at_front
=
858 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
;
860 crypt_stat
->num_header_bytes_at_front
= PAGE_CACHE_SIZE
;
865 * ecryptfs_compute_root_iv
868 * On error, sets the root IV to all 0's.
870 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat
*crypt_stat
)
873 char dst
[MD5_DIGEST_SIZE
];
875 BUG_ON(crypt_stat
->iv_bytes
> MD5_DIGEST_SIZE
);
876 BUG_ON(crypt_stat
->iv_bytes
<= 0);
877 if (!(crypt_stat
->flags
& ECRYPTFS_KEY_VALID
)) {
879 ecryptfs_printk(KERN_WARNING
, "Session key not valid; "
880 "cannot generate root IV\n");
883 rc
= ecryptfs_calculate_md5(dst
, crypt_stat
, crypt_stat
->key
,
884 crypt_stat
->key_size
);
886 ecryptfs_printk(KERN_WARNING
, "Error attempting to compute "
887 "MD5 while generating root IV\n");
890 memcpy(crypt_stat
->root_iv
, dst
, crypt_stat
->iv_bytes
);
893 memset(crypt_stat
->root_iv
, 0, crypt_stat
->iv_bytes
);
894 crypt_stat
->flags
|= ECRYPTFS_SECURITY_WARNING
;
899 static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat
*crypt_stat
)
901 get_random_bytes(crypt_stat
->key
, crypt_stat
->key_size
);
902 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
903 ecryptfs_compute_root_iv(crypt_stat
);
904 if (unlikely(ecryptfs_verbosity
> 0)) {
905 ecryptfs_printk(KERN_DEBUG
, "Generated new session key:\n");
906 ecryptfs_dump_hex(crypt_stat
->key
,
907 crypt_stat
->key_size
);
912 * ecryptfs_copy_mount_wide_flags_to_inode_flags
913 * @crypt_stat: The inode's cryptographic context
914 * @mount_crypt_stat: The mount point's cryptographic context
916 * This function propagates the mount-wide flags to individual inode
919 static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
920 struct ecryptfs_crypt_stat
*crypt_stat
,
921 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
)
923 if (mount_crypt_stat
->flags
& ECRYPTFS_XATTR_METADATA_ENABLED
)
924 crypt_stat
->flags
|= ECRYPTFS_METADATA_IN_XATTR
;
925 if (mount_crypt_stat
->flags
& ECRYPTFS_ENCRYPTED_VIEW_ENABLED
)
926 crypt_stat
->flags
|= ECRYPTFS_VIEW_AS_ENCRYPTED
;
929 static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
930 struct ecryptfs_crypt_stat
*crypt_stat
,
931 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
)
933 struct ecryptfs_global_auth_tok
*global_auth_tok
;
936 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
937 list_for_each_entry(global_auth_tok
,
938 &mount_crypt_stat
->global_auth_tok_list
,
939 mount_crypt_stat_list
) {
940 rc
= ecryptfs_add_keysig(crypt_stat
, global_auth_tok
->sig
);
942 printk(KERN_ERR
"Error adding keysig; rc = [%d]\n", rc
);
944 &mount_crypt_stat
->global_auth_tok_list_mutex
);
948 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
954 * ecryptfs_set_default_crypt_stat_vals
955 * @crypt_stat: The inode's cryptographic context
956 * @mount_crypt_stat: The mount point's cryptographic context
958 * Default values in the event that policy does not override them.
960 static void ecryptfs_set_default_crypt_stat_vals(
961 struct ecryptfs_crypt_stat
*crypt_stat
,
962 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
)
964 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat
,
966 ecryptfs_set_default_sizes(crypt_stat
);
967 strcpy(crypt_stat
->cipher
, ECRYPTFS_DEFAULT_CIPHER
);
968 crypt_stat
->key_size
= ECRYPTFS_DEFAULT_KEY_BYTES
;
969 crypt_stat
->flags
&= ~(ECRYPTFS_KEY_VALID
);
970 crypt_stat
->file_version
= ECRYPTFS_FILE_VERSION
;
971 crypt_stat
->mount_crypt_stat
= mount_crypt_stat
;
975 * ecryptfs_new_file_context
976 * @ecryptfs_dentry: The eCryptfs dentry
978 * If the crypto context for the file has not yet been established,
979 * this is where we do that. Establishing a new crypto context
980 * involves the following decisions:
981 * - What cipher to use?
982 * - What set of authentication tokens to use?
983 * Here we just worry about getting enough information into the
984 * authentication tokens so that we know that they are available.
985 * We associate the available authentication tokens with the new file
986 * via the set of signatures in the crypt_stat struct. Later, when
987 * the headers are actually written out, we may again defer to
988 * userspace to perform the encryption of the session key; for the
989 * foreseeable future, this will be the case with public key packets.
991 * Returns zero on success; non-zero otherwise
993 int ecryptfs_new_file_context(struct dentry
*ecryptfs_dentry
)
995 struct ecryptfs_crypt_stat
*crypt_stat
=
996 &ecryptfs_inode_to_private(ecryptfs_dentry
->d_inode
)->crypt_stat
;
997 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
998 &ecryptfs_superblock_to_private(
999 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
1000 int cipher_name_len
;
1003 ecryptfs_set_default_crypt_stat_vals(crypt_stat
, mount_crypt_stat
);
1004 crypt_stat
->flags
|= (ECRYPTFS_ENCRYPTED
| ECRYPTFS_KEY_VALID
);
1005 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat
,
1007 rc
= ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat
,
1010 printk(KERN_ERR
"Error attempting to copy mount-wide key sigs "
1011 "to the inode key sigs; rc = [%d]\n", rc
);
1015 strlen(mount_crypt_stat
->global_default_cipher_name
);
1016 memcpy(crypt_stat
->cipher
,
1017 mount_crypt_stat
->global_default_cipher_name
,
1019 crypt_stat
->cipher
[cipher_name_len
] = '\0';
1020 crypt_stat
->key_size
=
1021 mount_crypt_stat
->global_default_cipher_key_size
;
1022 ecryptfs_generate_new_key(crypt_stat
);
1023 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1025 ecryptfs_printk(KERN_ERR
, "Error initializing cryptographic "
1026 "context for cipher [%s]: rc = [%d]\n",
1027 crypt_stat
->cipher
, rc
);
1033 * contains_ecryptfs_marker - check for the ecryptfs marker
1034 * @data: The data block in which to check
1036 * Returns one if marker found; zero if not found
1038 static int contains_ecryptfs_marker(char *data
)
1042 m_1
= get_unaligned_be32(data
);
1043 m_2
= get_unaligned_be32(data
+ 4);
1044 if ((m_1
^ MAGIC_ECRYPTFS_MARKER
) == m_2
)
1046 ecryptfs_printk(KERN_DEBUG
, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1047 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1
, m_2
,
1048 MAGIC_ECRYPTFS_MARKER
);
1049 ecryptfs_printk(KERN_DEBUG
, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1050 "[0x%.8x]\n", (m_1
^ MAGIC_ECRYPTFS_MARKER
));
1054 struct ecryptfs_flag_map_elem
{
1059 /* Add support for additional flags by adding elements here. */
1060 static struct ecryptfs_flag_map_elem ecryptfs_flag_map
[] = {
1061 {0x00000001, ECRYPTFS_ENABLE_HMAC
},
1062 {0x00000002, ECRYPTFS_ENCRYPTED
},
1063 {0x00000004, ECRYPTFS_METADATA_IN_XATTR
}
1067 * ecryptfs_process_flags
1068 * @crypt_stat: The cryptographic context
1069 * @page_virt: Source data to be parsed
1070 * @bytes_read: Updated with the number of bytes read
1072 * Returns zero on success; non-zero if the flag set is invalid
1074 static int ecryptfs_process_flags(struct ecryptfs_crypt_stat
*crypt_stat
,
1075 char *page_virt
, int *bytes_read
)
1081 flags
= get_unaligned_be32(page_virt
);
1082 for (i
= 0; i
< ((sizeof(ecryptfs_flag_map
)
1083 / sizeof(struct ecryptfs_flag_map_elem
))); i
++)
1084 if (flags
& ecryptfs_flag_map
[i
].file_flag
) {
1085 crypt_stat
->flags
|= ecryptfs_flag_map
[i
].local_flag
;
1087 crypt_stat
->flags
&= ~(ecryptfs_flag_map
[i
].local_flag
);
1088 /* Version is in top 8 bits of the 32-bit flag vector */
1089 crypt_stat
->file_version
= ((flags
>> 24) & 0xFF);
1095 * write_ecryptfs_marker
1096 * @page_virt: The pointer to in a page to begin writing the marker
1097 * @written: Number of bytes written
1099 * Marker = 0x3c81b7f5
1101 static void write_ecryptfs_marker(char *page_virt
, size_t *written
)
1105 get_random_bytes(&m_1
, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
/ 2));
1106 m_2
= (m_1
^ MAGIC_ECRYPTFS_MARKER
);
1107 put_unaligned_be32(m_1
, page_virt
);
1108 page_virt
+= (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
/ 2);
1109 put_unaligned_be32(m_2
, page_virt
);
1110 (*written
) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
;
1114 write_ecryptfs_flags(char *page_virt
, struct ecryptfs_crypt_stat
*crypt_stat
,
1120 for (i
= 0; i
< ((sizeof(ecryptfs_flag_map
)
1121 / sizeof(struct ecryptfs_flag_map_elem
))); i
++)
1122 if (crypt_stat
->flags
& ecryptfs_flag_map
[i
].local_flag
)
1123 flags
|= ecryptfs_flag_map
[i
].file_flag
;
1124 /* Version is in top 8 bits of the 32-bit flag vector */
1125 flags
|= ((((u8
)crypt_stat
->file_version
) << 24) & 0xFF000000);
1126 put_unaligned_be32(flags
, page_virt
);
1130 struct ecryptfs_cipher_code_str_map_elem
{
1131 char cipher_str
[16];
1135 /* Add support for additional ciphers by adding elements here. The
1136 * cipher_code is whatever OpenPGP applicatoins use to identify the
1137 * ciphers. List in order of probability. */
1138 static struct ecryptfs_cipher_code_str_map_elem
1139 ecryptfs_cipher_code_str_map
[] = {
1140 {"aes",RFC2440_CIPHER_AES_128
},
1141 {"blowfish", RFC2440_CIPHER_BLOWFISH
},
1142 {"des3_ede", RFC2440_CIPHER_DES3_EDE
},
1143 {"cast5", RFC2440_CIPHER_CAST_5
},
1144 {"twofish", RFC2440_CIPHER_TWOFISH
},
1145 {"cast6", RFC2440_CIPHER_CAST_6
},
1146 {"aes", RFC2440_CIPHER_AES_192
},
1147 {"aes", RFC2440_CIPHER_AES_256
}
1151 * ecryptfs_code_for_cipher_string
1152 * @cipher_name: The string alias for the cipher
1153 * @key_bytes: Length of key in bytes; used for AES code selection
1155 * Returns zero on no match, or the cipher code on match
1157 u8
ecryptfs_code_for_cipher_string(char *cipher_name
, size_t key_bytes
)
1161 struct ecryptfs_cipher_code_str_map_elem
*map
=
1162 ecryptfs_cipher_code_str_map
;
1164 if (strcmp(cipher_name
, "aes") == 0) {
1165 switch (key_bytes
) {
1167 code
= RFC2440_CIPHER_AES_128
;
1170 code
= RFC2440_CIPHER_AES_192
;
1173 code
= RFC2440_CIPHER_AES_256
;
1176 for (i
= 0; i
< ARRAY_SIZE(ecryptfs_cipher_code_str_map
); i
++)
1177 if (strcmp(cipher_name
, map
[i
].cipher_str
) == 0) {
1178 code
= map
[i
].cipher_code
;
1186 * ecryptfs_cipher_code_to_string
1187 * @str: Destination to write out the cipher name
1188 * @cipher_code: The code to convert to cipher name string
1190 * Returns zero on success
1192 int ecryptfs_cipher_code_to_string(char *str
, u8 cipher_code
)
1198 for (i
= 0; i
< ARRAY_SIZE(ecryptfs_cipher_code_str_map
); i
++)
1199 if (cipher_code
== ecryptfs_cipher_code_str_map
[i
].cipher_code
)
1200 strcpy(str
, ecryptfs_cipher_code_str_map
[i
].cipher_str
);
1201 if (str
[0] == '\0') {
1202 ecryptfs_printk(KERN_WARNING
, "Cipher code not recognized: "
1203 "[%d]\n", cipher_code
);
1209 int ecryptfs_read_and_validate_header_region(char *data
,
1210 struct inode
*ecryptfs_inode
)
1212 struct ecryptfs_crypt_stat
*crypt_stat
=
1213 &(ecryptfs_inode_to_private(ecryptfs_inode
)->crypt_stat
);
1216 rc
= ecryptfs_read_lower(data
, 0, crypt_stat
->extent_size
,
1219 printk(KERN_ERR
"%s: Error reading header region; rc = [%d]\n",
1223 if (!contains_ecryptfs_marker(data
+ ECRYPTFS_FILE_SIZE_BYTES
)) {
1225 ecryptfs_printk(KERN_DEBUG
, "Valid marker not found\n");
1232 ecryptfs_write_header_metadata(char *virt
,
1233 struct ecryptfs_crypt_stat
*crypt_stat
,
1236 u32 header_extent_size
;
1237 u16 num_header_extents_at_front
;
1239 header_extent_size
= (u32
)crypt_stat
->extent_size
;
1240 num_header_extents_at_front
=
1241 (u16
)(crypt_stat
->num_header_bytes_at_front
1242 / crypt_stat
->extent_size
);
1243 put_unaligned_be32(header_extent_size
, virt
);
1245 put_unaligned_be16(num_header_extents_at_front
, virt
);
1249 struct kmem_cache
*ecryptfs_header_cache_1
;
1250 struct kmem_cache
*ecryptfs_header_cache_2
;
1253 * ecryptfs_write_headers_virt
1254 * @page_virt: The virtual address to write the headers to
1255 * @max: The size of memory allocated at page_virt
1256 * @size: Set to the number of bytes written by this function
1257 * @crypt_stat: The cryptographic context
1258 * @ecryptfs_dentry: The eCryptfs dentry
1263 * Octets 0-7: Unencrypted file size (big-endian)
1264 * Octets 8-15: eCryptfs special marker
1265 * Octets 16-19: Flags
1266 * Octet 16: File format version number (between 0 and 255)
1267 * Octets 17-18: Reserved
1268 * Octet 19: Bit 1 (lsb): Reserved
1270 * Bits 3-8: Reserved
1271 * Octets 20-23: Header extent size (big-endian)
1272 * Octets 24-25: Number of header extents at front of file
1274 * Octet 26: Begin RFC 2440 authentication token packet set
1276 * Lower data (CBC encrypted)
1278 * Lower data (CBC encrypted)
1281 * Returns zero on success
1283 static int ecryptfs_write_headers_virt(char *page_virt
, size_t max
,
1285 struct ecryptfs_crypt_stat
*crypt_stat
,
1286 struct dentry
*ecryptfs_dentry
)
1292 offset
= ECRYPTFS_FILE_SIZE_BYTES
;
1293 write_ecryptfs_marker((page_virt
+ offset
), &written
);
1295 write_ecryptfs_flags((page_virt
+ offset
), crypt_stat
, &written
);
1297 ecryptfs_write_header_metadata((page_virt
+ offset
), crypt_stat
,
1300 rc
= ecryptfs_generate_key_packet_set((page_virt
+ offset
), crypt_stat
,
1301 ecryptfs_dentry
, &written
,
1304 ecryptfs_printk(KERN_WARNING
, "Error generating key packet "
1305 "set; rc = [%d]\n", rc
);
1314 ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat
*crypt_stat
,
1315 struct dentry
*ecryptfs_dentry
,
1320 rc
= ecryptfs_write_lower(ecryptfs_dentry
->d_inode
, virt
,
1321 0, crypt_stat
->num_header_bytes_at_front
);
1323 printk(KERN_ERR
"%s: Error attempting to write header "
1324 "information to lower file; rc = [%d]\n", __func__
,
1330 ecryptfs_write_metadata_to_xattr(struct dentry
*ecryptfs_dentry
,
1331 struct ecryptfs_crypt_stat
*crypt_stat
,
1332 char *page_virt
, size_t size
)
1336 rc
= ecryptfs_setxattr(ecryptfs_dentry
, ECRYPTFS_XATTR_NAME
, page_virt
,
1342 * ecryptfs_write_metadata
1343 * @ecryptfs_dentry: The eCryptfs dentry
1345 * Write the file headers out. This will likely involve a userspace
1346 * callout, in which the session key is encrypted with one or more
1347 * public keys and/or the passphrase necessary to do the encryption is
1348 * retrieved via a prompt. Exactly what happens at this point should
1349 * be policy-dependent.
1351 * Returns zero on success; non-zero on error
1353 int ecryptfs_write_metadata(struct dentry
*ecryptfs_dentry
)
1355 struct ecryptfs_crypt_stat
*crypt_stat
=
1356 &ecryptfs_inode_to_private(ecryptfs_dentry
->d_inode
)->crypt_stat
;
1361 if (likely(crypt_stat
->flags
& ECRYPTFS_ENCRYPTED
)) {
1362 if (!(crypt_stat
->flags
& ECRYPTFS_KEY_VALID
)) {
1363 printk(KERN_ERR
"Key is invalid; bailing out\n");
1368 printk(KERN_WARNING
"%s: Encrypted flag not set\n",
1373 /* Released in this function */
1374 virt
= (char *)get_zeroed_page(GFP_KERNEL
);
1376 printk(KERN_ERR
"%s: Out of memory\n", __func__
);
1380 rc
= ecryptfs_write_headers_virt(virt
, PAGE_CACHE_SIZE
, &size
,
1381 crypt_stat
, ecryptfs_dentry
);
1383 printk(KERN_ERR
"%s: Error whilst writing headers; rc = [%d]\n",
1387 if (crypt_stat
->flags
& ECRYPTFS_METADATA_IN_XATTR
)
1388 rc
= ecryptfs_write_metadata_to_xattr(ecryptfs_dentry
,
1389 crypt_stat
, virt
, size
);
1391 rc
= ecryptfs_write_metadata_to_contents(crypt_stat
,
1392 ecryptfs_dentry
, virt
);
1394 printk(KERN_ERR
"%s: Error writing metadata out to lower file; "
1395 "rc = [%d]\n", __func__
, rc
);
1399 free_page((unsigned long)virt
);
1404 #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1405 #define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1406 static int parse_header_metadata(struct ecryptfs_crypt_stat
*crypt_stat
,
1407 char *virt
, int *bytes_read
,
1408 int validate_header_size
)
1411 u32 header_extent_size
;
1412 u16 num_header_extents_at_front
;
1414 header_extent_size
= get_unaligned_be32(virt
);
1415 virt
+= sizeof(__be32
);
1416 num_header_extents_at_front
= get_unaligned_be16(virt
);
1417 crypt_stat
->num_header_bytes_at_front
=
1418 (((size_t)num_header_extents_at_front
1419 * (size_t)header_extent_size
));
1420 (*bytes_read
) = (sizeof(__be32
) + sizeof(__be16
));
1421 if ((validate_header_size
== ECRYPTFS_VALIDATE_HEADER_SIZE
)
1422 && (crypt_stat
->num_header_bytes_at_front
1423 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
)) {
1425 printk(KERN_WARNING
"Invalid header size: [%zd]\n",
1426 crypt_stat
->num_header_bytes_at_front
);
1432 * set_default_header_data
1433 * @crypt_stat: The cryptographic context
1435 * For version 0 file format; this function is only for backwards
1436 * compatibility for files created with the prior versions of
1439 static void set_default_header_data(struct ecryptfs_crypt_stat
*crypt_stat
)
1441 crypt_stat
->num_header_bytes_at_front
=
1442 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
;
1446 * ecryptfs_read_headers_virt
1447 * @page_virt: The virtual address into which to read the headers
1448 * @crypt_stat: The cryptographic context
1449 * @ecryptfs_dentry: The eCryptfs dentry
1450 * @validate_header_size: Whether to validate the header size while reading
1452 * Read/parse the header data. The header format is detailed in the
1453 * comment block for the ecryptfs_write_headers_virt() function.
1455 * Returns zero on success
1457 static int ecryptfs_read_headers_virt(char *page_virt
,
1458 struct ecryptfs_crypt_stat
*crypt_stat
,
1459 struct dentry
*ecryptfs_dentry
,
1460 int validate_header_size
)
1466 ecryptfs_set_default_sizes(crypt_stat
);
1467 crypt_stat
->mount_crypt_stat
= &ecryptfs_superblock_to_private(
1468 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
1469 offset
= ECRYPTFS_FILE_SIZE_BYTES
;
1470 rc
= contains_ecryptfs_marker(page_virt
+ offset
);
1475 offset
+= MAGIC_ECRYPTFS_MARKER_SIZE_BYTES
;
1476 rc
= ecryptfs_process_flags(crypt_stat
, (page_virt
+ offset
),
1479 ecryptfs_printk(KERN_WARNING
, "Error processing flags\n");
1482 if (crypt_stat
->file_version
> ECRYPTFS_SUPPORTED_FILE_VERSION
) {
1483 ecryptfs_printk(KERN_WARNING
, "File version is [%d]; only "
1484 "file version [%d] is supported by this "
1485 "version of eCryptfs\n",
1486 crypt_stat
->file_version
,
1487 ECRYPTFS_SUPPORTED_FILE_VERSION
);
1491 offset
+= bytes_read
;
1492 if (crypt_stat
->file_version
>= 1) {
1493 rc
= parse_header_metadata(crypt_stat
, (page_virt
+ offset
),
1494 &bytes_read
, validate_header_size
);
1496 ecryptfs_printk(KERN_WARNING
, "Error reading header "
1497 "metadata; rc = [%d]\n", rc
);
1499 offset
+= bytes_read
;
1501 set_default_header_data(crypt_stat
);
1502 rc
= ecryptfs_parse_packet_set(crypt_stat
, (page_virt
+ offset
),
1509 * ecryptfs_read_xattr_region
1510 * @page_virt: The vitual address into which to read the xattr data
1511 * @ecryptfs_inode: The eCryptfs inode
1513 * Attempts to read the crypto metadata from the extended attribute
1514 * region of the lower file.
1516 * Returns zero on success; non-zero on error
1518 int ecryptfs_read_xattr_region(char *page_virt
, struct inode
*ecryptfs_inode
)
1520 struct dentry
*lower_dentry
=
1521 ecryptfs_inode_to_private(ecryptfs_inode
)->lower_file
->f_dentry
;
1525 size
= ecryptfs_getxattr_lower(lower_dentry
, ECRYPTFS_XATTR_NAME
,
1526 page_virt
, ECRYPTFS_DEFAULT_EXTENT_SIZE
);
1528 if (unlikely(ecryptfs_verbosity
> 0))
1529 printk(KERN_INFO
"Error attempting to read the [%s] "
1530 "xattr from the lower file; return value = "
1531 "[%zd]\n", ECRYPTFS_XATTR_NAME
, size
);
1539 int ecryptfs_read_and_validate_xattr_region(char *page_virt
,
1540 struct dentry
*ecryptfs_dentry
)
1544 rc
= ecryptfs_read_xattr_region(page_virt
, ecryptfs_dentry
->d_inode
);
1547 if (!contains_ecryptfs_marker(page_virt
+ ECRYPTFS_FILE_SIZE_BYTES
)) {
1548 printk(KERN_WARNING
"Valid data found in [%s] xattr, but "
1549 "the marker is invalid\n", ECRYPTFS_XATTR_NAME
);
1557 * ecryptfs_read_metadata
1559 * Common entry point for reading file metadata. From here, we could
1560 * retrieve the header information from the header region of the file,
1561 * the xattr region of the file, or some other repostory that is
1562 * stored separately from the file itself. The current implementation
1563 * supports retrieving the metadata information from the file contents
1564 * and from the xattr region.
1566 * Returns zero if valid headers found and parsed; non-zero otherwise
1568 int ecryptfs_read_metadata(struct dentry
*ecryptfs_dentry
)
1571 char *page_virt
= NULL
;
1572 struct inode
*ecryptfs_inode
= ecryptfs_dentry
->d_inode
;
1573 struct ecryptfs_crypt_stat
*crypt_stat
=
1574 &ecryptfs_inode_to_private(ecryptfs_inode
)->crypt_stat
;
1575 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1576 &ecryptfs_superblock_to_private(
1577 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
1579 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat
,
1581 /* Read the first page from the underlying file */
1582 page_virt
= kmem_cache_alloc(ecryptfs_header_cache_1
, GFP_USER
);
1585 printk(KERN_ERR
"%s: Unable to allocate page_virt\n",
1589 rc
= ecryptfs_read_lower(page_virt
, 0, crypt_stat
->extent_size
,
1592 rc
= ecryptfs_read_headers_virt(page_virt
, crypt_stat
,
1594 ECRYPTFS_VALIDATE_HEADER_SIZE
);
1596 rc
= ecryptfs_read_xattr_region(page_virt
, ecryptfs_inode
);
1598 printk(KERN_DEBUG
"Valid eCryptfs headers not found in "
1599 "file header region or xattr region\n");
1603 rc
= ecryptfs_read_headers_virt(page_virt
, crypt_stat
,
1605 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE
);
1607 printk(KERN_DEBUG
"Valid eCryptfs headers not found in "
1608 "file xattr region either\n");
1611 if (crypt_stat
->mount_crypt_stat
->flags
1612 & ECRYPTFS_XATTR_METADATA_ENABLED
) {
1613 crypt_stat
->flags
|= ECRYPTFS_METADATA_IN_XATTR
;
1615 printk(KERN_WARNING
"Attempt to access file with "
1616 "crypto metadata only in the extended attribute "
1617 "region, but eCryptfs was mounted without "
1618 "xattr support enabled. eCryptfs will not treat "
1619 "this like an encrypted file.\n");
1625 memset(page_virt
, 0, PAGE_CACHE_SIZE
);
1626 kmem_cache_free(ecryptfs_header_cache_1
, page_virt
);
1632 * ecryptfs_encode_filename - converts a plaintext file name to cipher text
1633 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
1634 * @name: The plaintext name
1635 * @length: The length of the plaintext
1636 * @encoded_name: The encypted name
1638 * Encrypts and encodes a filename into something that constitutes a
1639 * valid filename for a filesystem, with printable characters.
1641 * We assume that we have a properly initialized crypto context,
1642 * pointed to by crypt_stat->tfm.
1644 * TODO: Implement filename decoding and decryption here, in place of
1645 * memcpy. We are keeping the framework around for now to (1)
1646 * facilitate testing of the components needed to implement filename
1647 * encryption and (2) to provide a code base from which other
1648 * developers in the community can easily implement this feature.
1650 * Returns the length of encoded filename; negative if error
1653 ecryptfs_encode_filename(struct ecryptfs_crypt_stat
*crypt_stat
,
1654 const char *name
, int length
, char **encoded_name
)
1658 (*encoded_name
) = kmalloc(length
+ 2, GFP_KERNEL
);
1659 if (!(*encoded_name
)) {
1663 /* TODO: Filename encryption is a scheduled feature for a
1664 * future version of eCryptfs. This function is here only for
1665 * the purpose of providing a framework for other developers
1666 * to easily implement filename encryption. Hint: Replace this
1667 * memcpy() with a call to encrypt and encode the
1668 * filename, the set the length accordingly. */
1669 memcpy((void *)(*encoded_name
), (void *)name
, length
);
1670 (*encoded_name
)[length
] = '\0';
1677 * ecryptfs_decode_filename - converts the cipher text name to plaintext
1678 * @crypt_stat: The crypt_stat struct associated with the file
1679 * @name: The filename in cipher text
1680 * @length: The length of the cipher text name
1681 * @decrypted_name: The plaintext name
1683 * Decodes and decrypts the filename.
1685 * We assume that we have a properly initialized crypto context,
1686 * pointed to by crypt_stat->tfm.
1688 * TODO: Implement filename decoding and decryption here, in place of
1689 * memcpy. We are keeping the framework around for now to (1)
1690 * facilitate testing of the components needed to implement filename
1691 * encryption and (2) to provide a code base from which other
1692 * developers in the community can easily implement this feature.
1694 * Returns the length of decoded filename; negative if error
1697 ecryptfs_decode_filename(struct ecryptfs_crypt_stat
*crypt_stat
,
1698 const char *name
, int length
, char **decrypted_name
)
1702 (*decrypted_name
) = kmalloc(length
+ 2, GFP_KERNEL
);
1703 if (!(*decrypted_name
)) {
1707 /* TODO: Filename encryption is a scheduled feature for a
1708 * future version of eCryptfs. This function is here only for
1709 * the purpose of providing a framework for other developers
1710 * to easily implement filename encryption. Hint: Replace this
1711 * memcpy() with a call to decode and decrypt the
1712 * filename, the set the length accordingly. */
1713 memcpy((void *)(*decrypted_name
), (void *)name
, length
);
1714 (*decrypted_name
)[length
+ 1] = '\0'; /* Only for convenience
1715 * in printing out the
1724 * ecryptfs_encrypt_filename - encrypt filename
1726 * CBC-encrypts the filename. We do not want to encrypt the same
1727 * filename with the same key and IV, which may happen with hard
1728 * links, so we prepend random bits to each filename.
1730 * Returns zero on success; non-zero otherwise
1733 ecryptfs_encrypt_filename(struct ecryptfs_filename
*filename
,
1734 struct ecryptfs_crypt_stat
*crypt_stat
,
1735 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
)
1739 filename
->encrypted_filename
= NULL
;
1740 filename
->encrypted_filename_size
= 0;
1741 if ((crypt_stat
&& (crypt_stat
->flags
& ECRYPTFS_ENCFN_USE_MOUNT_FNEK
))
1742 || (mount_crypt_stat
&& (mount_crypt_stat
->flags
1743 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK
))) {
1745 size_t remaining_bytes
;
1747 rc
= ecryptfs_write_tag_70_packet(
1749 &filename
->encrypted_filename_size
,
1750 mount_crypt_stat
, NULL
,
1751 filename
->filename_size
);
1753 printk(KERN_ERR
"%s: Error attempting to get packet "
1754 "size for tag 72; rc = [%d]\n", __func__
,
1756 filename
->encrypted_filename_size
= 0;
1759 filename
->encrypted_filename
=
1760 kmalloc(filename
->encrypted_filename_size
, GFP_KERNEL
);
1761 if (!filename
->encrypted_filename
) {
1762 printk(KERN_ERR
"%s: Out of memory whilst attempting "
1763 "to kmalloc [%Zd] bytes\n", __func__
,
1764 filename
->encrypted_filename_size
);
1768 remaining_bytes
= filename
->encrypted_filename_size
;
1769 rc
= ecryptfs_write_tag_70_packet(filename
->encrypted_filename
,
1774 filename
->filename_size
);
1776 printk(KERN_ERR
"%s: Error attempting to generate "
1777 "tag 70 packet; rc = [%d]\n", __func__
,
1779 kfree(filename
->encrypted_filename
);
1780 filename
->encrypted_filename
= NULL
;
1781 filename
->encrypted_filename_size
= 0;
1784 filename
->encrypted_filename_size
= packet_size
;
1786 printk(KERN_ERR
"%s: No support for requested filename "
1787 "encryption method in this release\n", __func__
);
1795 static int ecryptfs_copy_filename(char **copied_name
, size_t *copied_name_size
,
1796 const char *name
, size_t name_size
)
1800 (*copied_name
) = kmalloc((name_size
+ 2), GFP_KERNEL
);
1801 if (!(*copied_name
)) {
1805 memcpy((void *)(*copied_name
), (void *)name
, name_size
);
1806 (*copied_name
)[(name_size
)] = '\0'; /* Only for convenience
1807 * in printing out the
1810 (*copied_name_size
) = (name_size
+ 1);
1816 * ecryptfs_process_key_cipher - Perform key cipher initialization.
1817 * @key_tfm: Crypto context for key material, set by this function
1818 * @cipher_name: Name of the cipher
1819 * @key_size: Size of the key in bytes
1821 * Returns zero on success. Any crypto_tfm structs allocated here
1822 * should be released by other functions, such as on a superblock put
1823 * event, regardless of whether this function succeeds for fails.
1826 ecryptfs_process_key_cipher(struct crypto_blkcipher
**key_tfm
,
1827 char *cipher_name
, size_t *key_size
)
1829 char dummy_key
[ECRYPTFS_MAX_KEY_BYTES
];
1830 char *full_alg_name
;
1834 if (*key_size
> ECRYPTFS_MAX_KEY_BYTES
) {
1836 printk(KERN_ERR
"Requested key size is [%Zd] bytes; maximum "
1837 "allowable is [%d]\n", *key_size
, ECRYPTFS_MAX_KEY_BYTES
);
1840 rc
= ecryptfs_crypto_api_algify_cipher_name(&full_alg_name
, cipher_name
,
1844 *key_tfm
= crypto_alloc_blkcipher(full_alg_name
, 0, CRYPTO_ALG_ASYNC
);
1845 kfree(full_alg_name
);
1846 if (IS_ERR(*key_tfm
)) {
1847 rc
= PTR_ERR(*key_tfm
);
1848 printk(KERN_ERR
"Unable to allocate crypto cipher with name "
1849 "[%s]; rc = [%d]\n", cipher_name
, rc
);
1852 crypto_blkcipher_set_flags(*key_tfm
, CRYPTO_TFM_REQ_WEAK_KEY
);
1853 if (*key_size
== 0) {
1854 struct blkcipher_alg
*alg
= crypto_blkcipher_alg(*key_tfm
);
1856 *key_size
= alg
->max_keysize
;
1858 get_random_bytes(dummy_key
, *key_size
);
1859 rc
= crypto_blkcipher_setkey(*key_tfm
, dummy_key
, *key_size
);
1861 printk(KERN_ERR
"Error attempting to set key of size [%Zd] for "
1862 "cipher [%s]; rc = [%d]\n", *key_size
, cipher_name
, rc
);
1870 struct kmem_cache
*ecryptfs_key_tfm_cache
;
1871 static struct list_head key_tfm_list
;
1872 struct mutex key_tfm_list_mutex
;
1874 int ecryptfs_init_crypto(void)
1876 mutex_init(&key_tfm_list_mutex
);
1877 INIT_LIST_HEAD(&key_tfm_list
);
1882 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1884 * Called only at module unload time
1886 int ecryptfs_destroy_crypto(void)
1888 struct ecryptfs_key_tfm
*key_tfm
, *key_tfm_tmp
;
1890 mutex_lock(&key_tfm_list_mutex
);
1891 list_for_each_entry_safe(key_tfm
, key_tfm_tmp
, &key_tfm_list
,
1893 list_del(&key_tfm
->key_tfm_list
);
1894 if (key_tfm
->key_tfm
)
1895 crypto_free_blkcipher(key_tfm
->key_tfm
);
1896 kmem_cache_free(ecryptfs_key_tfm_cache
, key_tfm
);
1898 mutex_unlock(&key_tfm_list_mutex
);
1903 ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm
**key_tfm
, char *cipher_name
,
1906 struct ecryptfs_key_tfm
*tmp_tfm
;
1909 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex
));
1911 tmp_tfm
= kmem_cache_alloc(ecryptfs_key_tfm_cache
, GFP_KERNEL
);
1912 if (key_tfm
!= NULL
)
1913 (*key_tfm
) = tmp_tfm
;
1916 printk(KERN_ERR
"Error attempting to allocate from "
1917 "ecryptfs_key_tfm_cache\n");
1920 mutex_init(&tmp_tfm
->key_tfm_mutex
);
1921 strncpy(tmp_tfm
->cipher_name
, cipher_name
,
1922 ECRYPTFS_MAX_CIPHER_NAME_SIZE
);
1923 tmp_tfm
->cipher_name
[ECRYPTFS_MAX_CIPHER_NAME_SIZE
] = '\0';
1924 tmp_tfm
->key_size
= key_size
;
1925 rc
= ecryptfs_process_key_cipher(&tmp_tfm
->key_tfm
,
1926 tmp_tfm
->cipher_name
,
1927 &tmp_tfm
->key_size
);
1929 printk(KERN_ERR
"Error attempting to initialize key TFM "
1930 "cipher with name = [%s]; rc = [%d]\n",
1931 tmp_tfm
->cipher_name
, rc
);
1932 kmem_cache_free(ecryptfs_key_tfm_cache
, tmp_tfm
);
1933 if (key_tfm
!= NULL
)
1937 list_add(&tmp_tfm
->key_tfm_list
, &key_tfm_list
);
1943 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1944 * @cipher_name: the name of the cipher to search for
1945 * @key_tfm: set to corresponding tfm if found
1947 * Searches for cached key_tfm matching @cipher_name
1948 * Must be called with &key_tfm_list_mutex held
1949 * Returns 1 if found, with @key_tfm set
1950 * Returns 0 if not found, with @key_tfm set to NULL
1952 int ecryptfs_tfm_exists(char *cipher_name
, struct ecryptfs_key_tfm
**key_tfm
)
1954 struct ecryptfs_key_tfm
*tmp_key_tfm
;
1956 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex
));
1958 list_for_each_entry(tmp_key_tfm
, &key_tfm_list
, key_tfm_list
) {
1959 if (strcmp(tmp_key_tfm
->cipher_name
, cipher_name
) == 0) {
1961 (*key_tfm
) = tmp_key_tfm
;
1971 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1973 * @tfm: set to cached tfm found, or new tfm created
1974 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1975 * @cipher_name: the name of the cipher to search for and/or add
1977 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1978 * Searches for cached item first, and creates new if not found.
1979 * Returns 0 on success, non-zero if adding new cipher failed
1981 int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher
**tfm
,
1982 struct mutex
**tfm_mutex
,
1985 struct ecryptfs_key_tfm
*key_tfm
;
1989 (*tfm_mutex
) = NULL
;
1991 mutex_lock(&key_tfm_list_mutex
);
1992 if (!ecryptfs_tfm_exists(cipher_name
, &key_tfm
)) {
1993 rc
= ecryptfs_add_new_key_tfm(&key_tfm
, cipher_name
, 0);
1995 printk(KERN_ERR
"Error adding new key_tfm to list; "
2000 (*tfm
) = key_tfm
->key_tfm
;
2001 (*tfm_mutex
) = &key_tfm
->key_tfm_mutex
;
2003 mutex_unlock(&key_tfm_list_mutex
);
2007 /* 64 characters forming a 6-bit target field */
2008 static unsigned char *portable_filename_chars
= ("-.0123456789ABCD"
2011 "klmnopqrstuvwxyz");
2013 /* We could either offset on every reverse map or just pad some 0x00's
2014 * at the front here */
2015 static unsigned char filename_rev_map
[] = {
2016 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
2017 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
2018 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
2019 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
2020 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
2021 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
2022 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
2023 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
2024 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
2025 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
2026 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
2027 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
2028 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
2029 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
2030 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
2035 * ecryptfs_encode_for_filename
2036 * @dst: Destination location for encoded filename
2037 * @dst_size: Size of the encoded filename in bytes
2038 * @src: Source location for the filename to encode
2039 * @src_size: Size of the source in bytes
2041 void ecryptfs_encode_for_filename(unsigned char *dst
, size_t *dst_size
,
2042 unsigned char *src
, size_t src_size
)
2045 size_t block_num
= 0;
2046 size_t dst_offset
= 0;
2047 unsigned char last_block
[3];
2049 if (src_size
== 0) {
2053 num_blocks
= (src_size
/ 3);
2054 if ((src_size
% 3) == 0) {
2055 memcpy(last_block
, (&src
[src_size
- 3]), 3);
2058 last_block
[2] = 0x00;
2059 switch (src_size
% 3) {
2061 last_block
[0] = src
[src_size
- 1];
2062 last_block
[1] = 0x00;
2065 last_block
[0] = src
[src_size
- 2];
2066 last_block
[1] = src
[src_size
- 1];
2069 (*dst_size
) = (num_blocks
* 4);
2072 while (block_num
< num_blocks
) {
2073 unsigned char *src_block
;
2074 unsigned char dst_block
[4];
2076 if (block_num
== (num_blocks
- 1))
2077 src_block
= last_block
;
2079 src_block
= &src
[block_num
* 3];
2080 dst_block
[0] = ((src_block
[0] >> 2) & 0x3F);
2081 dst_block
[1] = (((src_block
[0] << 4) & 0x30)
2082 | ((src_block
[1] >> 4) & 0x0F));
2083 dst_block
[2] = (((src_block
[1] << 2) & 0x3C)
2084 | ((src_block
[2] >> 6) & 0x03));
2085 dst_block
[3] = (src_block
[2] & 0x3F);
2086 dst
[dst_offset
++] = portable_filename_chars
[dst_block
[0]];
2087 dst
[dst_offset
++] = portable_filename_chars
[dst_block
[1]];
2088 dst
[dst_offset
++] = portable_filename_chars
[dst_block
[2]];
2089 dst
[dst_offset
++] = portable_filename_chars
[dst_block
[3]];
2096 int ecryptfs_decode_from_filename(unsigned char *dst
, size_t *dst_size
,
2097 const unsigned char *src
, size_t src_size
)
2099 u8 current_bit_offset
= 0;
2100 size_t src_byte_offset
= 0;
2101 size_t dst_byte_offset
= 0;
2105 /* Not exact; conservatively long */
2106 (*dst_size
) = (((src_size
+ 1) * 3) / 4);
2109 while (src_byte_offset
< src_size
) {
2110 unsigned char src_byte
=
2111 filename_rev_map
[(int)src
[src_byte_offset
]];
2113 switch (current_bit_offset
) {
2115 dst
[dst_byte_offset
] = (src_byte
<< 2);
2116 current_bit_offset
= 6;
2119 dst
[dst_byte_offset
++] |= (src_byte
>> 4);
2120 dst
[dst_byte_offset
] = ((src_byte
& 0xF)
2122 current_bit_offset
= 4;
2125 dst
[dst_byte_offset
++] |= (src_byte
>> 2);
2126 dst
[dst_byte_offset
] = (src_byte
<< 6);
2127 current_bit_offset
= 2;
2130 dst
[dst_byte_offset
++] |= (src_byte
);
2131 dst
[dst_byte_offset
] = 0;
2132 current_bit_offset
= 0;
2137 (*dst_size
) = dst_byte_offset
;
2143 * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
2144 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
2145 * @name: The plaintext name
2146 * @length: The length of the plaintext
2147 * @encoded_name: The encypted name
2149 * Encrypts and encodes a filename into something that constitutes a
2150 * valid filename for a filesystem, with printable characters.
2152 * We assume that we have a properly initialized crypto context,
2153 * pointed to by crypt_stat->tfm.
2155 * Returns zero on success; non-zero on otherwise
2157 int ecryptfs_encrypt_and_encode_filename(
2158 char **encoded_name
,
2159 size_t *encoded_name_size
,
2160 struct ecryptfs_crypt_stat
*crypt_stat
,
2161 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
2162 const char *name
, size_t name_size
)
2164 size_t encoded_name_no_prefix_size
;
2167 (*encoded_name
) = NULL
;
2168 (*encoded_name_size
) = 0;
2169 if ((crypt_stat
&& (crypt_stat
->flags
& ECRYPTFS_ENCRYPT_FILENAMES
))
2170 || (mount_crypt_stat
&& (mount_crypt_stat
->flags
2171 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
))) {
2172 struct ecryptfs_filename
*filename
;
2174 filename
= kzalloc(sizeof(*filename
), GFP_KERNEL
);
2176 printk(KERN_ERR
"%s: Out of memory whilst attempting "
2177 "to kzalloc [%d] bytes\n", __func__
,
2182 filename
->filename
= (char *)name
;
2183 filename
->filename_size
= name_size
;
2184 rc
= ecryptfs_encrypt_filename(filename
, crypt_stat
,
2187 printk(KERN_ERR
"%s: Error attempting to encrypt "
2188 "filename; rc = [%d]\n", __func__
, rc
);
2192 ecryptfs_encode_for_filename(
2193 NULL
, &encoded_name_no_prefix_size
,
2194 filename
->encrypted_filename
,
2195 filename
->encrypted_filename_size
);
2196 if ((crypt_stat
&& (crypt_stat
->flags
2197 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK
))
2198 || (mount_crypt_stat
2199 && (mount_crypt_stat
->flags
2200 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK
)))
2201 (*encoded_name_size
) =
2202 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2203 + encoded_name_no_prefix_size
);
2205 (*encoded_name_size
) =
2206 (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2207 + encoded_name_no_prefix_size
);
2208 (*encoded_name
) = kmalloc((*encoded_name_size
) + 1, GFP_KERNEL
);
2209 if (!(*encoded_name
)) {
2210 printk(KERN_ERR
"%s: Out of memory whilst attempting "
2211 "to kzalloc [%d] bytes\n", __func__
,
2212 (*encoded_name_size
));
2214 kfree(filename
->encrypted_filename
);
2218 if ((crypt_stat
&& (crypt_stat
->flags
2219 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK
))
2220 || (mount_crypt_stat
2221 && (mount_crypt_stat
->flags
2222 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK
))) {
2223 memcpy((*encoded_name
),
2224 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX
,
2225 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
);
2226 ecryptfs_encode_for_filename(
2228 + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
),
2229 &encoded_name_no_prefix_size
,
2230 filename
->encrypted_filename
,
2231 filename
->encrypted_filename_size
);
2232 (*encoded_name_size
) =
2233 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2234 + encoded_name_no_prefix_size
);
2235 (*encoded_name
)[(*encoded_name_size
)] = '\0';
2236 (*encoded_name_size
)++;
2241 printk(KERN_ERR
"%s: Error attempting to encode "
2242 "encrypted filename; rc = [%d]\n", __func__
,
2244 kfree((*encoded_name
));
2245 (*encoded_name
) = NULL
;
2246 (*encoded_name_size
) = 0;
2248 kfree(filename
->encrypted_filename
);
2251 rc
= ecryptfs_copy_filename(encoded_name
,
2260 * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
2261 * @plaintext_name: The plaintext name
2262 * @plaintext_name_size: The plaintext name size
2263 * @ecryptfs_dir_dentry: eCryptfs directory dentry
2264 * @name: The filename in cipher text
2265 * @name_size: The cipher text name size
2267 * Decrypts and decodes the filename.
2269 * Returns zero on error; non-zero otherwise
2271 int ecryptfs_decode_and_decrypt_filename(char **plaintext_name
,
2272 size_t *plaintext_name_size
,
2273 struct dentry
*ecryptfs_dir_dentry
,
2274 const char *name
, size_t name_size
)
2277 size_t decoded_name_size
;
2281 if ((name_size
> ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
)
2282 && (strncmp(name
, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX
,
2283 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
) == 0)) {
2284 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
2285 &ecryptfs_superblock_to_private(
2286 ecryptfs_dir_dentry
->d_sb
)->mount_crypt_stat
;
2287 const char *orig_name
= name
;
2288 size_t orig_name_size
= name_size
;
2290 name
+= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
;
2291 name_size
-= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
;
2292 rc
= ecryptfs_decode_from_filename(NULL
, &decoded_name_size
,
2295 printk(KERN_ERR
"%s: Error attempting to decode "
2296 "filename; rc = [%d]\n", __func__
, rc
);
2297 rc
= ecryptfs_copy_filename(plaintext_name
,
2298 plaintext_name_size
,
2299 orig_name
, orig_name_size
);
2302 decoded_name
= kmalloc(decoded_name_size
, GFP_KERNEL
);
2303 if (!decoded_name
) {
2304 printk(KERN_ERR
"%s: Out of memory whilst attempting "
2305 "to kmalloc [%Zd] bytes\n", __func__
,
2310 rc
= ecryptfs_decode_from_filename(decoded_name
,
2314 printk(KERN_ERR
"%s: Error attempting to decode "
2315 "filename; rc = [%d]\n", __func__
, rc
);
2316 rc
= ecryptfs_copy_filename(plaintext_name
,
2317 plaintext_name_size
,
2318 orig_name
, orig_name_size
);
2321 rc
= ecryptfs_parse_tag_70_packet(plaintext_name
,
2322 plaintext_name_size
,
2328 printk(KERN_INFO
"%s: Could not parse tag 70 packet "
2329 "from filename; copying through filename "
2330 "as-is\n", __func__
);
2331 rc
= ecryptfs_copy_filename(plaintext_name
,
2332 plaintext_name_size
,
2333 orig_name
, orig_name_size
);
2337 rc
= ecryptfs_copy_filename(plaintext_name
,
2338 plaintext_name_size
,
2343 kfree(decoded_name
);