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 <linux/slab.h>
37 #include <asm/unaligned.h>
38 #include "ecryptfs_kernel.h"
41 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
42 struct page *dst_page, struct page *src_page,
43 int offset, int size, unsigned char *iv);
45 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
46 struct page *dst_page, struct page *src_page,
47 int offset, int size, unsigned char *iv);
51 * @dst: Buffer to take hex character representation of contents of
52 * src; must be at least of size (src_size * 2)
53 * @src: Buffer to be converted to a hex string respresentation
54 * @src_size: number of bytes to convert
56 void ecryptfs_to_hex(char *dst, char *src, size_t src_size)
60 for (x = 0; x < src_size; x++)
61 sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]);
66 * @dst: Buffer to take the bytes from src hex; must be at least of
68 * @src: Buffer to be converted from a hex string respresentation to raw value
69 * @dst_size: size of dst buffer, or number of hex characters pairs to convert
71 void ecryptfs_from_hex(char *dst, char *src, int dst_size)
76 for (x = 0; x < dst_size; x++) {
78 tmp[1] = src[x * 2 + 1];
79 dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
84 * ecryptfs_calculate_md5 - calculates the md5 of @src
85 * @dst: Pointer to 16 bytes of allocated memory
86 * @crypt_stat: Pointer to crypt_stat struct for the current inode
87 * @src: Data to be md5'd
88 * @len: Length of @src
90 * Uses the allocated crypto context that crypt_stat references to
91 * generate the MD5 sum of the contents of src.
93 static int ecryptfs_calculate_md5(char *dst,
94 struct ecryptfs_crypt_stat *crypt_stat,
97 struct scatterlist sg;
98 struct hash_desc desc = {
99 .tfm = crypt_stat->hash_tfm,
100 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
104 mutex_lock(&crypt_stat->cs_hash_tfm_mutex);
105 sg_init_one(&sg, (u8 *)src, len);
107 desc.tfm = crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH, 0,
109 if (IS_ERR(desc.tfm)) {
110 rc = PTR_ERR(desc.tfm);
111 ecryptfs_printk(KERN_ERR, "Error attempting to "
112 "allocate crypto context; rc = [%d]\n",
116 crypt_stat->hash_tfm = desc.tfm;
118 rc = crypto_hash_init(&desc);
121 "%s: Error initializing crypto hash; rc = [%d]\n",
125 rc = crypto_hash_update(&desc, &sg, len);
128 "%s: Error updating crypto hash; rc = [%d]\n",
132 rc = crypto_hash_final(&desc, dst);
135 "%s: Error finalizing crypto hash; rc = [%d]\n",
140 mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
144 static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
146 char *chaining_modifier)
148 int cipher_name_len = strlen(cipher_name);
149 int chaining_modifier_len = strlen(chaining_modifier);
150 int algified_name_len;
153 algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
154 (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
155 if (!(*algified_name)) {
159 snprintf((*algified_name), algified_name_len, "%s(%s)",
160 chaining_modifier, cipher_name);
168 * @iv: destination for the derived iv vale
169 * @crypt_stat: Pointer to crypt_stat struct for the current inode
170 * @offset: Offset of the extent whose IV we are to derive
172 * Generate the initialization vector from the given root IV and page
175 * Returns zero on success; non-zero on error.
177 int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
181 char dst[MD5_DIGEST_SIZE];
182 char src[ECRYPTFS_MAX_IV_BYTES + 16];
184 if (unlikely(ecryptfs_verbosity > 0)) {
185 ecryptfs_printk(KERN_DEBUG, "root iv:\n");
186 ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
188 /* TODO: It is probably secure to just cast the least
189 * significant bits of the root IV into an unsigned long and
190 * add the offset to that rather than go through all this
191 * hashing business. -Halcrow */
192 memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
193 memset((src + crypt_stat->iv_bytes), 0, 16);
194 snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
195 if (unlikely(ecryptfs_verbosity > 0)) {
196 ecryptfs_printk(KERN_DEBUG, "source:\n");
197 ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
199 rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
200 (crypt_stat->iv_bytes + 16));
202 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
203 "MD5 while generating IV for a page\n");
206 memcpy(iv, dst, crypt_stat->iv_bytes);
207 if (unlikely(ecryptfs_verbosity > 0)) {
208 ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
209 ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
216 * ecryptfs_init_crypt_stat
217 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
219 * Initialize the crypt_stat structure.
222 ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
224 memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
225 INIT_LIST_HEAD(&crypt_stat->keysig_list);
226 mutex_init(&crypt_stat->keysig_list_mutex);
227 mutex_init(&crypt_stat->cs_mutex);
228 mutex_init(&crypt_stat->cs_tfm_mutex);
229 mutex_init(&crypt_stat->cs_hash_tfm_mutex);
230 crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
234 * ecryptfs_destroy_crypt_stat
235 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
237 * Releases all memory associated with a crypt_stat struct.
239 void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
241 struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
244 crypto_free_ablkcipher(crypt_stat->tfm);
245 if (crypt_stat->hash_tfm)
246 crypto_free_hash(crypt_stat->hash_tfm);
247 list_for_each_entry_safe(key_sig, key_sig_tmp,
248 &crypt_stat->keysig_list, crypt_stat_list) {
249 list_del(&key_sig->crypt_stat_list);
250 kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
252 memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
255 void ecryptfs_destroy_mount_crypt_stat(
256 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
258 struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
260 if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
262 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
263 list_for_each_entry_safe(auth_tok, auth_tok_tmp,
264 &mount_crypt_stat->global_auth_tok_list,
265 mount_crypt_stat_list) {
266 list_del(&auth_tok->mount_crypt_stat_list);
267 if (auth_tok->global_auth_tok_key
268 && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
269 key_put(auth_tok->global_auth_tok_key);
270 kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
272 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
273 memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
277 * virt_to_scatterlist
278 * @addr: Virtual address
279 * @size: Size of data; should be an even multiple of the block size
280 * @sg: Pointer to scatterlist array; set to NULL to obtain only
281 * the number of scatterlist structs required in array
282 * @sg_size: Max array size
284 * Fills in a scatterlist array with page references for a passed
287 * Returns the number of scatterlist structs in array used
289 int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
295 int remainder_of_page;
297 sg_init_table(sg, sg_size);
299 while (size > 0 && i < sg_size) {
300 pg = virt_to_page(addr);
301 offset = offset_in_page(addr);
302 sg_set_page(&sg[i], pg, 0, offset);
303 remainder_of_page = PAGE_CACHE_SIZE - offset;
304 if (size >= remainder_of_page) {
305 sg[i].length = remainder_of_page;
306 addr += remainder_of_page;
307 size -= remainder_of_page;
320 struct extent_crypt_result {
321 struct completion completion;
325 static void extent_crypt_complete(struct crypto_async_request *req, int rc)
327 struct extent_crypt_result *ecr = req->data;
329 if (rc == -EINPROGRESS)
333 complete(&ecr->completion);
337 * encrypt_scatterlist
338 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
339 * @dest_sg: Destination of encrypted data
340 * @src_sg: Data to be encrypted
341 * @size: Length of data to be encrypted
342 * @iv: iv to use during encryption
344 * Returns the number of bytes encrypted; negative value on error
346 static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
347 struct scatterlist *dest_sg,
348 struct scatterlist *src_sg, int size,
351 struct ablkcipher_request *req = NULL;
352 struct extent_crypt_result ecr;
355 BUG_ON(!crypt_stat || !crypt_stat->tfm
356 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
357 if (unlikely(ecryptfs_verbosity > 0)) {
358 ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
359 crypt_stat->key_size);
360 ecryptfs_dump_hex(crypt_stat->key,
361 crypt_stat->key_size);
364 init_completion(&ecr.completion);
366 mutex_lock(&crypt_stat->cs_tfm_mutex);
367 req = ablkcipher_request_alloc(crypt_stat->tfm, GFP_NOFS);
369 mutex_unlock(&crypt_stat->cs_tfm_mutex);
374 ablkcipher_request_set_callback(req,
375 CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
376 extent_crypt_complete, &ecr);
377 /* Consider doing this once, when the file is opened */
378 if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
379 rc = crypto_ablkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
380 crypt_stat->key_size);
382 ecryptfs_printk(KERN_ERR,
383 "Error setting key; rc = [%d]\n",
385 mutex_unlock(&crypt_stat->cs_tfm_mutex);
389 crypt_stat->flags |= ECRYPTFS_KEY_SET;
391 mutex_unlock(&crypt_stat->cs_tfm_mutex);
392 ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size);
393 ablkcipher_request_set_crypt(req, src_sg, dest_sg, size, iv);
394 rc = crypto_ablkcipher_encrypt(req);
395 if (rc == -EINPROGRESS || rc == -EBUSY) {
396 struct extent_crypt_result *ecr = req->base.data;
398 wait_for_completion(&ecr->completion);
400 INIT_COMPLETION(ecr->completion);
403 ablkcipher_request_free(req);
408 * lower_offset_for_page
410 * Convert an eCryptfs page index into a lower byte offset
412 static loff_t lower_offset_for_page(struct ecryptfs_crypt_stat *crypt_stat,
415 return ecryptfs_lower_header_size(crypt_stat) +
416 (page->index << PAGE_CACHE_SHIFT);
420 * ecryptfs_encrypt_extent
421 * @enc_extent_page: Allocated page into which to encrypt the data in
423 * @crypt_stat: crypt_stat containing cryptographic context for the
424 * encryption operation
425 * @page: Page containing plaintext data extent to encrypt
426 * @extent_offset: Page extent offset for use in generating IV
428 * Encrypts one extent of data.
430 * Return zero on success; non-zero otherwise
432 static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
433 struct ecryptfs_crypt_stat *crypt_stat,
435 unsigned long extent_offset)
438 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
441 extent_base = (((loff_t)page->index)
442 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
443 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
444 (extent_base + extent_offset));
446 ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
447 "extent [0x%.16llx]; rc = [%d]\n",
448 (unsigned long long)(extent_base + extent_offset), rc);
451 rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, page,
452 extent_offset * crypt_stat->extent_size,
453 crypt_stat->extent_size, extent_iv);
455 printk(KERN_ERR "%s: Error attempting to encrypt page with "
456 "page->index = [%ld], extent_offset = [%ld]; "
457 "rc = [%d]\n", __func__, page->index, extent_offset,
467 * ecryptfs_encrypt_page
468 * @page: Page mapped from the eCryptfs inode for the file; contains
469 * decrypted content that needs to be encrypted (to a temporary
470 * page; not in place) and written out to the lower file
472 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
473 * that eCryptfs pages may straddle the lower pages -- for instance,
474 * if the file was created on a machine with an 8K page size
475 * (resulting in an 8K header), and then the file is copied onto a
476 * host with a 32K page size, then when reading page 0 of the eCryptfs
477 * file, 24K of page 0 of the lower file will be read and decrypted,
478 * and then 8K of page 1 of the lower file will be read and decrypted.
480 * Returns zero on success; negative on error
482 int ecryptfs_encrypt_page(struct page *page)
484 struct inode *ecryptfs_inode;
485 struct ecryptfs_crypt_stat *crypt_stat;
486 char *enc_extent_virt;
487 struct page *enc_extent_page = NULL;
488 loff_t extent_offset;
492 ecryptfs_inode = page->mapping->host;
494 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
495 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
496 enc_extent_page = alloc_page(GFP_USER);
497 if (!enc_extent_page) {
499 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
500 "encrypted extent\n");
504 for (extent_offset = 0;
505 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
507 rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
510 printk(KERN_ERR "%s: Error encrypting extent; "
511 "rc = [%d]\n", __func__, rc);
516 lower_offset = lower_offset_for_page(crypt_stat, page);
517 enc_extent_virt = kmap(enc_extent_page);
518 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset,
520 kunmap(enc_extent_page);
522 ecryptfs_printk(KERN_ERR,
523 "Error attempting to write lower page; rc = [%d]\n",
529 if (enc_extent_page) {
530 __free_page(enc_extent_page);
535 static int ecryptfs_decrypt_extent(struct page *page,
536 struct ecryptfs_crypt_stat *crypt_stat,
537 struct page *enc_extent_page,
538 unsigned long extent_offset)
541 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
544 extent_base = (((loff_t)page->index)
545 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
546 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
547 (extent_base + extent_offset));
549 ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
550 "extent [0x%.16llx]; rc = [%d]\n",
551 (unsigned long long)(extent_base + extent_offset), rc);
554 rc = ecryptfs_decrypt_page_offset(crypt_stat, page, enc_extent_page,
555 extent_offset * crypt_stat->extent_size,
556 crypt_stat->extent_size, extent_iv);
558 printk(KERN_ERR "%s: Error attempting to decrypt to page with "
559 "page->index = [%ld], extent_offset = [%ld]; "
560 "rc = [%d]\n", __func__, page->index, extent_offset,
570 * ecryptfs_decrypt_page
571 * @page: Page mapped from the eCryptfs inode for the file; data read
572 * and decrypted from the lower file will be written into this
575 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
576 * that eCryptfs pages may straddle the lower pages -- for instance,
577 * if the file was created on a machine with an 8K page size
578 * (resulting in an 8K header), and then the file is copied onto a
579 * host with a 32K page size, then when reading page 0 of the eCryptfs
580 * file, 24K of page 0 of the lower file will be read and decrypted,
581 * and then 8K of page 1 of the lower file will be read and decrypted.
583 * Returns zero on success; negative on error
585 int ecryptfs_decrypt_page(struct page *page)
587 struct inode *ecryptfs_inode;
588 struct ecryptfs_crypt_stat *crypt_stat;
590 unsigned long extent_offset;
594 ecryptfs_inode = page->mapping->host;
596 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
597 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
599 lower_offset = lower_offset_for_page(crypt_stat, page);
600 page_virt = kmap(page);
601 rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_CACHE_SIZE,
605 ecryptfs_printk(KERN_ERR,
606 "Error attempting to read lower page; rc = [%d]\n",
611 for (extent_offset = 0;
612 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
614 rc = ecryptfs_decrypt_extent(page, crypt_stat, page,
617 printk(KERN_ERR "%s: Error encrypting extent; "
618 "rc = [%d]\n", __func__, rc);
627 * decrypt_scatterlist
628 * @crypt_stat: Cryptographic context
629 * @dest_sg: The destination scatterlist to decrypt into
630 * @src_sg: The source scatterlist to decrypt from
631 * @size: The number of bytes to decrypt
632 * @iv: The initialization vector to use for the decryption
634 * Returns the number of bytes decrypted; negative value on error
636 static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
637 struct scatterlist *dest_sg,
638 struct scatterlist *src_sg, int size,
641 struct ablkcipher_request *req = NULL;
642 struct extent_crypt_result ecr;
645 BUG_ON(!crypt_stat || !crypt_stat->tfm
646 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
647 if (unlikely(ecryptfs_verbosity > 0)) {
648 ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
649 crypt_stat->key_size);
650 ecryptfs_dump_hex(crypt_stat->key,
651 crypt_stat->key_size);
654 init_completion(&ecr.completion);
656 mutex_lock(&crypt_stat->cs_tfm_mutex);
657 req = ablkcipher_request_alloc(crypt_stat->tfm, GFP_NOFS);
659 mutex_unlock(&crypt_stat->cs_tfm_mutex);
664 ablkcipher_request_set_callback(req,
665 CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
666 extent_crypt_complete, &ecr);
667 /* Consider doing this once, when the file is opened */
668 if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
669 rc = crypto_ablkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
670 crypt_stat->key_size);
672 ecryptfs_printk(KERN_ERR,
673 "Error setting key; rc = [%d]\n",
675 mutex_unlock(&crypt_stat->cs_tfm_mutex);
679 crypt_stat->flags |= ECRYPTFS_KEY_SET;
681 mutex_unlock(&crypt_stat->cs_tfm_mutex);
682 ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
683 ablkcipher_request_set_crypt(req, src_sg, dest_sg, size, iv);
684 rc = crypto_ablkcipher_decrypt(req);
685 if (rc == -EINPROGRESS || rc == -EBUSY) {
686 struct extent_crypt_result *ecr = req->base.data;
688 wait_for_completion(&ecr->completion);
690 INIT_COMPLETION(ecr->completion);
693 ablkcipher_request_free(req);
699 * ecryptfs_encrypt_page_offset
700 * @crypt_stat: The cryptographic context
701 * @dst_page: The page to encrypt into
702 * @src_page: The page to encrypt from
703 * @offset: The byte offset into the dst_page and src_page
704 * @size: The number of bytes to encrypt
705 * @iv: The initialization vector to use for the encryption
707 * Returns the number of bytes encrypted
710 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
711 struct page *dst_page, struct page *src_page,
712 int offset, int size, unsigned char *iv)
714 struct scatterlist src_sg, dst_sg;
716 sg_init_table(&src_sg, 1);
717 sg_init_table(&dst_sg, 1);
719 sg_set_page(&src_sg, src_page, size, offset);
720 sg_set_page(&dst_sg, dst_page, size, offset);
721 return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
725 * ecryptfs_decrypt_page_offset
726 * @crypt_stat: The cryptographic context
727 * @dst_page: The page to decrypt into
728 * @src_page: The page to decrypt from
729 * @offset: The byte offset into the dst_page and src_page
730 * @size: The number of bytes to decrypt
731 * @iv: The initialization vector to use for the decryption
733 * Returns the number of bytes decrypted
736 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
737 struct page *dst_page, struct page *src_page,
738 int offset, int size, unsigned char *iv)
740 struct scatterlist src_sg, dst_sg;
742 sg_init_table(&src_sg, 1);
743 sg_set_page(&src_sg, src_page, size, offset);
745 sg_init_table(&dst_sg, 1);
746 sg_set_page(&dst_sg, dst_page, size, offset);
748 return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
751 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
754 * ecryptfs_init_crypt_ctx
755 * @crypt_stat: Uninitialized crypt stats structure
757 * Initialize the crypto context.
759 * TODO: Performance: Keep a cache of initialized cipher contexts;
760 * only init if needed
762 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
767 if (!crypt_stat->cipher) {
768 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
771 ecryptfs_printk(KERN_DEBUG,
772 "Initializing cipher [%s]; strlen = [%d]; "
773 "key_size_bits = [%zd]\n",
774 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
775 crypt_stat->key_size << 3);
776 if (crypt_stat->tfm) {
780 mutex_lock(&crypt_stat->cs_tfm_mutex);
781 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
782 crypt_stat->cipher, "cbc");
785 crypt_stat->tfm = crypto_alloc_ablkcipher(full_alg_name, 0, 0);
786 kfree(full_alg_name);
787 if (IS_ERR(crypt_stat->tfm)) {
788 rc = PTR_ERR(crypt_stat->tfm);
789 crypt_stat->tfm = NULL;
790 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
791 "Error initializing cipher [%s]\n",
795 crypto_ablkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
798 mutex_unlock(&crypt_stat->cs_tfm_mutex);
803 static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
807 crypt_stat->extent_mask = 0xFFFFFFFF;
808 crypt_stat->extent_shift = 0;
809 if (crypt_stat->extent_size == 0)
811 extent_size_tmp = crypt_stat->extent_size;
812 while ((extent_size_tmp & 0x01) == 0) {
813 extent_size_tmp >>= 1;
814 crypt_stat->extent_mask <<= 1;
815 crypt_stat->extent_shift++;
819 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
821 /* Default values; may be overwritten as we are parsing the
823 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
824 set_extent_mask_and_shift(crypt_stat);
825 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
826 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
827 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
829 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
830 crypt_stat->metadata_size =
831 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
833 crypt_stat->metadata_size = PAGE_CACHE_SIZE;
838 * ecryptfs_compute_root_iv
841 * On error, sets the root IV to all 0's.
843 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
846 char dst[MD5_DIGEST_SIZE];
848 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
849 BUG_ON(crypt_stat->iv_bytes <= 0);
850 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
852 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
853 "cannot generate root IV\n");
856 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
857 crypt_stat->key_size);
859 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
860 "MD5 while generating root IV\n");
863 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
866 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
867 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
872 static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
874 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
875 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
876 ecryptfs_compute_root_iv(crypt_stat);
877 if (unlikely(ecryptfs_verbosity > 0)) {
878 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
879 ecryptfs_dump_hex(crypt_stat->key,
880 crypt_stat->key_size);
885 * ecryptfs_copy_mount_wide_flags_to_inode_flags
886 * @crypt_stat: The inode's cryptographic context
887 * @mount_crypt_stat: The mount point's cryptographic context
889 * This function propagates the mount-wide flags to individual inode
892 static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
893 struct ecryptfs_crypt_stat *crypt_stat,
894 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
896 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
897 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
898 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
899 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
900 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
901 crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
902 if (mount_crypt_stat->flags
903 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
904 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
905 else if (mount_crypt_stat->flags
906 & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
907 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
911 static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
912 struct ecryptfs_crypt_stat *crypt_stat,
913 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
915 struct ecryptfs_global_auth_tok *global_auth_tok;
918 mutex_lock(&crypt_stat->keysig_list_mutex);
919 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
921 list_for_each_entry(global_auth_tok,
922 &mount_crypt_stat->global_auth_tok_list,
923 mount_crypt_stat_list) {
924 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
926 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
928 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
934 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
935 mutex_unlock(&crypt_stat->keysig_list_mutex);
940 * ecryptfs_set_default_crypt_stat_vals
941 * @crypt_stat: The inode's cryptographic context
942 * @mount_crypt_stat: The mount point's cryptographic context
944 * Default values in the event that policy does not override them.
946 static void ecryptfs_set_default_crypt_stat_vals(
947 struct ecryptfs_crypt_stat *crypt_stat,
948 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
950 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
952 ecryptfs_set_default_sizes(crypt_stat);
953 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
954 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
955 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
956 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
957 crypt_stat->mount_crypt_stat = mount_crypt_stat;
961 * ecryptfs_new_file_context
962 * @ecryptfs_inode: The eCryptfs inode
964 * If the crypto context for the file has not yet been established,
965 * this is where we do that. Establishing a new crypto context
966 * involves the following decisions:
967 * - What cipher to use?
968 * - What set of authentication tokens to use?
969 * Here we just worry about getting enough information into the
970 * authentication tokens so that we know that they are available.
971 * We associate the available authentication tokens with the new file
972 * via the set of signatures in the crypt_stat struct. Later, when
973 * the headers are actually written out, we may again defer to
974 * userspace to perform the encryption of the session key; for the
975 * foreseeable future, this will be the case with public key packets.
977 * Returns zero on success; non-zero otherwise
979 int ecryptfs_new_file_context(struct inode *ecryptfs_inode)
981 struct ecryptfs_crypt_stat *crypt_stat =
982 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
983 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
984 &ecryptfs_superblock_to_private(
985 ecryptfs_inode->i_sb)->mount_crypt_stat;
989 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
990 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
991 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
993 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
996 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
997 "to the inode key sigs; rc = [%d]\n", rc);
1001 strlen(mount_crypt_stat->global_default_cipher_name);
1002 memcpy(crypt_stat->cipher,
1003 mount_crypt_stat->global_default_cipher_name,
1005 crypt_stat->cipher[cipher_name_len] = '\0';
1006 crypt_stat->key_size =
1007 mount_crypt_stat->global_default_cipher_key_size;
1008 ecryptfs_generate_new_key(crypt_stat);
1009 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1011 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
1012 "context for cipher [%s]: rc = [%d]\n",
1013 crypt_stat->cipher, rc);
1019 * ecryptfs_validate_marker - check for the ecryptfs marker
1020 * @data: The data block in which to check
1022 * Returns zero if marker found; -EINVAL if not found
1024 static int ecryptfs_validate_marker(char *data)
1028 m_1 = get_unaligned_be32(data);
1029 m_2 = get_unaligned_be32(data + 4);
1030 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
1032 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1033 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1034 MAGIC_ECRYPTFS_MARKER);
1035 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1036 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1040 struct ecryptfs_flag_map_elem {
1045 /* Add support for additional flags by adding elements here. */
1046 static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1047 {0x00000001, ECRYPTFS_ENABLE_HMAC},
1048 {0x00000002, ECRYPTFS_ENCRYPTED},
1049 {0x00000004, ECRYPTFS_METADATA_IN_XATTR},
1050 {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
1054 * ecryptfs_process_flags
1055 * @crypt_stat: The cryptographic context
1056 * @page_virt: Source data to be parsed
1057 * @bytes_read: Updated with the number of bytes read
1059 * Returns zero on success; non-zero if the flag set is invalid
1061 static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1062 char *page_virt, int *bytes_read)
1068 flags = get_unaligned_be32(page_virt);
1069 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1070 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1071 if (flags & ecryptfs_flag_map[i].file_flag) {
1072 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
1074 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
1075 /* Version is in top 8 bits of the 32-bit flag vector */
1076 crypt_stat->file_version = ((flags >> 24) & 0xFF);
1082 * write_ecryptfs_marker
1083 * @page_virt: The pointer to in a page to begin writing the marker
1084 * @written: Number of bytes written
1086 * Marker = 0x3c81b7f5
1088 static void write_ecryptfs_marker(char *page_virt, size_t *written)
1092 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1093 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
1094 put_unaligned_be32(m_1, page_virt);
1095 page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
1096 put_unaligned_be32(m_2, page_virt);
1097 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1100 void ecryptfs_write_crypt_stat_flags(char *page_virt,
1101 struct ecryptfs_crypt_stat *crypt_stat,
1107 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1108 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1109 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
1110 flags |= ecryptfs_flag_map[i].file_flag;
1111 /* Version is in top 8 bits of the 32-bit flag vector */
1112 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
1113 put_unaligned_be32(flags, page_virt);
1117 struct ecryptfs_cipher_code_str_map_elem {
1118 char cipher_str[16];
1122 /* Add support for additional ciphers by adding elements here. The
1123 * cipher_code is whatever OpenPGP applicatoins use to identify the
1124 * ciphers. List in order of probability. */
1125 static struct ecryptfs_cipher_code_str_map_elem
1126 ecryptfs_cipher_code_str_map[] = {
1127 {"aes",RFC2440_CIPHER_AES_128 },
1128 {"blowfish", RFC2440_CIPHER_BLOWFISH},
1129 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1130 {"cast5", RFC2440_CIPHER_CAST_5},
1131 {"twofish", RFC2440_CIPHER_TWOFISH},
1132 {"cast6", RFC2440_CIPHER_CAST_6},
1133 {"aes", RFC2440_CIPHER_AES_192},
1134 {"aes", RFC2440_CIPHER_AES_256}
1138 * ecryptfs_code_for_cipher_string
1139 * @cipher_name: The string alias for the cipher
1140 * @key_bytes: Length of key in bytes; used for AES code selection
1142 * Returns zero on no match, or the cipher code on match
1144 u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
1148 struct ecryptfs_cipher_code_str_map_elem *map =
1149 ecryptfs_cipher_code_str_map;
1151 if (strcmp(cipher_name, "aes") == 0) {
1152 switch (key_bytes) {
1154 code = RFC2440_CIPHER_AES_128;
1157 code = RFC2440_CIPHER_AES_192;
1160 code = RFC2440_CIPHER_AES_256;
1163 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1164 if (strcmp(cipher_name, map[i].cipher_str) == 0) {
1165 code = map[i].cipher_code;
1173 * ecryptfs_cipher_code_to_string
1174 * @str: Destination to write out the cipher name
1175 * @cipher_code: The code to convert to cipher name string
1177 * Returns zero on success
1179 int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
1185 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1186 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1187 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1188 if (str[0] == '\0') {
1189 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1190 "[%d]\n", cipher_code);
1196 int ecryptfs_read_and_validate_header_region(struct inode *inode)
1198 u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1199 u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
1202 rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES,
1204 if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1205 return rc >= 0 ? -EINVAL : rc;
1206 rc = ecryptfs_validate_marker(marker);
1208 ecryptfs_i_size_init(file_size, inode);
1213 ecryptfs_write_header_metadata(char *virt,
1214 struct ecryptfs_crypt_stat *crypt_stat,
1217 u32 header_extent_size;
1218 u16 num_header_extents_at_front;
1220 header_extent_size = (u32)crypt_stat->extent_size;
1221 num_header_extents_at_front =
1222 (u16)(crypt_stat->metadata_size / crypt_stat->extent_size);
1223 put_unaligned_be32(header_extent_size, virt);
1225 put_unaligned_be16(num_header_extents_at_front, virt);
1229 struct kmem_cache *ecryptfs_header_cache;
1232 * ecryptfs_write_headers_virt
1233 * @page_virt: The virtual address to write the headers to
1234 * @max: The size of memory allocated at page_virt
1235 * @size: Set to the number of bytes written by this function
1236 * @crypt_stat: The cryptographic context
1237 * @ecryptfs_dentry: The eCryptfs dentry
1242 * Octets 0-7: Unencrypted file size (big-endian)
1243 * Octets 8-15: eCryptfs special marker
1244 * Octets 16-19: Flags
1245 * Octet 16: File format version number (between 0 and 255)
1246 * Octets 17-18: Reserved
1247 * Octet 19: Bit 1 (lsb): Reserved
1249 * Bits 3-8: Reserved
1250 * Octets 20-23: Header extent size (big-endian)
1251 * Octets 24-25: Number of header extents at front of file
1253 * Octet 26: Begin RFC 2440 authentication token packet set
1255 * Lower data (CBC encrypted)
1257 * Lower data (CBC encrypted)
1260 * Returns zero on success
1262 static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1264 struct ecryptfs_crypt_stat *crypt_stat,
1265 struct dentry *ecryptfs_dentry)
1271 offset = ECRYPTFS_FILE_SIZE_BYTES;
1272 write_ecryptfs_marker((page_virt + offset), &written);
1274 ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat,
1277 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1280 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1281 ecryptfs_dentry, &written,
1284 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1285 "set; rc = [%d]\n", rc);
1294 ecryptfs_write_metadata_to_contents(struct inode *ecryptfs_inode,
1295 char *virt, size_t virt_len)
1299 rc = ecryptfs_write_lower(ecryptfs_inode, virt,
1302 printk(KERN_ERR "%s: Error attempting to write header "
1303 "information to lower file; rc = [%d]\n", __func__, rc);
1310 ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1311 char *page_virt, size_t size)
1315 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1320 static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1325 page = alloc_pages(gfp_mask | __GFP_ZERO, order);
1327 return (unsigned long) page_address(page);
1332 * ecryptfs_write_metadata
1333 * @ecryptfs_dentry: The eCryptfs dentry, which should be negative
1334 * @ecryptfs_inode: The newly created eCryptfs inode
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,
1345 struct inode *ecryptfs_inode)
1347 struct ecryptfs_crypt_stat *crypt_stat =
1348 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1355 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1356 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
1357 printk(KERN_ERR "Key is invalid; bailing out\n");
1362 printk(KERN_WARNING "%s: Encrypted flag not set\n",
1367 virt_len = crypt_stat->metadata_size;
1368 order = get_order(virt_len);
1369 /* Released in this function */
1370 virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
1372 printk(KERN_ERR "%s: Out of memory\n", __func__);
1376 /* Zeroed page ensures the in-header unencrypted i_size is set to 0 */
1377 rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
1380 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
1384 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1385 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt,
1388 rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt,
1391 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
1392 "rc = [%d]\n", __func__, rc);
1396 free_pages((unsigned long)virt, order);
1401 #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1402 #define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1403 static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
1404 char *virt, int *bytes_read,
1405 int validate_header_size)
1408 u32 header_extent_size;
1409 u16 num_header_extents_at_front;
1411 header_extent_size = get_unaligned_be32(virt);
1412 virt += sizeof(__be32);
1413 num_header_extents_at_front = get_unaligned_be16(virt);
1414 crypt_stat->metadata_size = (((size_t)num_header_extents_at_front
1415 * (size_t)header_extent_size));
1416 (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
1417 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
1418 && (crypt_stat->metadata_size
1419 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
1421 printk(KERN_WARNING "Invalid header size: [%zd]\n",
1422 crypt_stat->metadata_size);
1428 * set_default_header_data
1429 * @crypt_stat: The cryptographic context
1431 * For version 0 file format; this function is only for backwards
1432 * compatibility for files created with the prior versions of
1435 static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1437 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
1440 void ecryptfs_i_size_init(const char *page_virt, struct inode *inode)
1442 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1443 struct ecryptfs_crypt_stat *crypt_stat;
1446 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
1448 &ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat;
1449 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
1450 file_size = i_size_read(ecryptfs_inode_to_lower(inode));
1451 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1452 file_size += crypt_stat->metadata_size;
1454 file_size = get_unaligned_be64(page_virt);
1455 i_size_write(inode, (loff_t)file_size);
1456 crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED;
1460 * ecryptfs_read_headers_virt
1461 * @page_virt: The virtual address into which to read the headers
1462 * @crypt_stat: The cryptographic context
1463 * @ecryptfs_dentry: The eCryptfs dentry
1464 * @validate_header_size: Whether to validate the header size while reading
1466 * Read/parse the header data. The header format is detailed in the
1467 * comment block for the ecryptfs_write_headers_virt() function.
1469 * Returns zero on success
1471 static int ecryptfs_read_headers_virt(char *page_virt,
1472 struct ecryptfs_crypt_stat *crypt_stat,
1473 struct dentry *ecryptfs_dentry,
1474 int validate_header_size)
1480 ecryptfs_set_default_sizes(crypt_stat);
1481 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1482 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1483 offset = ECRYPTFS_FILE_SIZE_BYTES;
1484 rc = ecryptfs_validate_marker(page_virt + offset);
1487 if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED))
1488 ecryptfs_i_size_init(page_virt, ecryptfs_dentry->d_inode);
1489 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1490 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1493 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1496 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1497 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1498 "file version [%d] is supported by this "
1499 "version of eCryptfs\n",
1500 crypt_stat->file_version,
1501 ECRYPTFS_SUPPORTED_FILE_VERSION);
1505 offset += bytes_read;
1506 if (crypt_stat->file_version >= 1) {
1507 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
1508 &bytes_read, validate_header_size);
1510 ecryptfs_printk(KERN_WARNING, "Error reading header "
1511 "metadata; rc = [%d]\n", rc);
1513 offset += bytes_read;
1515 set_default_header_data(crypt_stat);
1516 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1523 * ecryptfs_read_xattr_region
1524 * @page_virt: The vitual address into which to read the xattr data
1525 * @ecryptfs_inode: The eCryptfs inode
1527 * Attempts to read the crypto metadata from the extended attribute
1528 * region of the lower file.
1530 * Returns zero on success; non-zero on error
1532 int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
1534 struct dentry *lower_dentry =
1535 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
1539 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1540 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
1542 if (unlikely(ecryptfs_verbosity > 0))
1543 printk(KERN_INFO "Error attempting to read the [%s] "
1544 "xattr from the lower file; return value = "
1545 "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
1553 int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
1554 struct inode *inode)
1556 u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1557 u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
1560 rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1561 ECRYPTFS_XATTR_NAME, file_size,
1562 ECRYPTFS_SIZE_AND_MARKER_BYTES);
1563 if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1564 return rc >= 0 ? -EINVAL : rc;
1565 rc = ecryptfs_validate_marker(marker);
1567 ecryptfs_i_size_init(file_size, inode);
1572 * ecryptfs_read_metadata
1574 * Common entry point for reading file metadata. From here, we could
1575 * retrieve the header information from the header region of the file,
1576 * the xattr region of the file, or some other repostory that is
1577 * stored separately from the file itself. The current implementation
1578 * supports retrieving the metadata information from the file contents
1579 * and from the xattr region.
1581 * Returns zero if valid headers found and parsed; non-zero otherwise
1583 int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
1587 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
1588 struct ecryptfs_crypt_stat *crypt_stat =
1589 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1590 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1591 &ecryptfs_superblock_to_private(
1592 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1594 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1596 /* Read the first page from the underlying file */
1597 page_virt = kmem_cache_alloc(ecryptfs_header_cache, GFP_USER);
1600 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
1604 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1607 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1609 ECRYPTFS_VALIDATE_HEADER_SIZE);
1611 /* metadata is not in the file header, so try xattrs */
1612 memset(page_virt, 0, PAGE_CACHE_SIZE);
1613 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
1615 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1616 "file header region or xattr region, inode %lu\n",
1617 ecryptfs_inode->i_ino);
1621 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1623 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1625 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1626 "file xattr region either, inode %lu\n",
1627 ecryptfs_inode->i_ino);
1630 if (crypt_stat->mount_crypt_stat->flags
1631 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1632 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1634 printk(KERN_WARNING "Attempt to access file with "
1635 "crypto metadata only in the extended attribute "
1636 "region, but eCryptfs was mounted without "
1637 "xattr support enabled. eCryptfs will not treat "
1638 "this like an encrypted file, inode %lu\n",
1639 ecryptfs_inode->i_ino);
1645 memset(page_virt, 0, PAGE_CACHE_SIZE);
1646 kmem_cache_free(ecryptfs_header_cache, page_virt);
1652 * ecryptfs_encrypt_filename - encrypt filename
1654 * CBC-encrypts the filename. We do not want to encrypt the same
1655 * filename with the same key and IV, which may happen with hard
1656 * links, so we prepend random bits to each filename.
1658 * Returns zero on success; non-zero otherwise
1661 ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1662 struct ecryptfs_crypt_stat *crypt_stat,
1663 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1667 filename->encrypted_filename = NULL;
1668 filename->encrypted_filename_size = 0;
1669 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
1670 || (mount_crypt_stat && (mount_crypt_stat->flags
1671 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
1673 size_t remaining_bytes;
1675 rc = ecryptfs_write_tag_70_packet(
1677 &filename->encrypted_filename_size,
1678 mount_crypt_stat, NULL,
1679 filename->filename_size);
1681 printk(KERN_ERR "%s: Error attempting to get packet "
1682 "size for tag 72; rc = [%d]\n", __func__,
1684 filename->encrypted_filename_size = 0;
1687 filename->encrypted_filename =
1688 kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1689 if (!filename->encrypted_filename) {
1690 printk(KERN_ERR "%s: Out of memory whilst attempting "
1691 "to kmalloc [%zd] bytes\n", __func__,
1692 filename->encrypted_filename_size);
1696 remaining_bytes = filename->encrypted_filename_size;
1697 rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
1702 filename->filename_size);
1704 printk(KERN_ERR "%s: Error attempting to generate "
1705 "tag 70 packet; rc = [%d]\n", __func__,
1707 kfree(filename->encrypted_filename);
1708 filename->encrypted_filename = NULL;
1709 filename->encrypted_filename_size = 0;
1712 filename->encrypted_filename_size = packet_size;
1714 printk(KERN_ERR "%s: No support for requested filename "
1715 "encryption method in this release\n", __func__);
1723 static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1724 const char *name, size_t name_size)
1728 (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
1729 if (!(*copied_name)) {
1733 memcpy((void *)(*copied_name), (void *)name, name_size);
1734 (*copied_name)[(name_size)] = '\0'; /* Only for convenience
1735 * in printing out the
1738 (*copied_name_size) = name_size;
1744 * ecryptfs_process_key_cipher - Perform key cipher initialization.
1745 * @key_tfm: Crypto context for key material, set by this function
1746 * @cipher_name: Name of the cipher
1747 * @key_size: Size of the key in bytes
1749 * Returns zero on success. Any crypto_tfm structs allocated here
1750 * should be released by other functions, such as on a superblock put
1751 * event, regardless of whether this function succeeds for fails.
1754 ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1755 char *cipher_name, size_t *key_size)
1757 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
1758 char *full_alg_name = NULL;
1762 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
1764 printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
1765 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
1768 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1772 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1773 if (IS_ERR(*key_tfm)) {
1774 rc = PTR_ERR(*key_tfm);
1775 printk(KERN_ERR "Unable to allocate crypto cipher with name "
1776 "[%s]; rc = [%d]\n", full_alg_name, rc);
1779 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1780 if (*key_size == 0) {
1781 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1783 *key_size = alg->max_keysize;
1785 get_random_bytes(dummy_key, *key_size);
1786 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
1788 printk(KERN_ERR "Error attempting to set key of size [%zd] for "
1789 "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name,
1795 kfree(full_alg_name);
1799 struct kmem_cache *ecryptfs_key_tfm_cache;
1800 static struct list_head key_tfm_list;
1801 struct mutex key_tfm_list_mutex;
1803 int __init ecryptfs_init_crypto(void)
1805 mutex_init(&key_tfm_list_mutex);
1806 INIT_LIST_HEAD(&key_tfm_list);
1811 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1813 * Called only at module unload time
1815 int ecryptfs_destroy_crypto(void)
1817 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1819 mutex_lock(&key_tfm_list_mutex);
1820 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1822 list_del(&key_tfm->key_tfm_list);
1823 if (key_tfm->key_tfm)
1824 crypto_free_blkcipher(key_tfm->key_tfm);
1825 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1827 mutex_unlock(&key_tfm_list_mutex);
1832 ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1835 struct ecryptfs_key_tfm *tmp_tfm;
1838 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1840 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1841 if (key_tfm != NULL)
1842 (*key_tfm) = tmp_tfm;
1845 printk(KERN_ERR "Error attempting to allocate from "
1846 "ecryptfs_key_tfm_cache\n");
1849 mutex_init(&tmp_tfm->key_tfm_mutex);
1850 strncpy(tmp_tfm->cipher_name, cipher_name,
1851 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
1852 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
1853 tmp_tfm->key_size = key_size;
1854 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1855 tmp_tfm->cipher_name,
1856 &tmp_tfm->key_size);
1858 printk(KERN_ERR "Error attempting to initialize key TFM "
1859 "cipher with name = [%s]; rc = [%d]\n",
1860 tmp_tfm->cipher_name, rc);
1861 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1862 if (key_tfm != NULL)
1866 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
1872 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1873 * @cipher_name: the name of the cipher to search for
1874 * @key_tfm: set to corresponding tfm if found
1876 * Searches for cached key_tfm matching @cipher_name
1877 * Must be called with &key_tfm_list_mutex held
1878 * Returns 1 if found, with @key_tfm set
1879 * Returns 0 if not found, with @key_tfm set to NULL
1881 int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1883 struct ecryptfs_key_tfm *tmp_key_tfm;
1885 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1887 list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1888 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1890 (*key_tfm) = tmp_key_tfm;
1900 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1902 * @tfm: set to cached tfm found, or new tfm created
1903 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1904 * @cipher_name: the name of the cipher to search for and/or add
1906 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1907 * Searches for cached item first, and creates new if not found.
1908 * Returns 0 on success, non-zero if adding new cipher failed
1910 int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1911 struct mutex **tfm_mutex,
1914 struct ecryptfs_key_tfm *key_tfm;
1918 (*tfm_mutex) = NULL;
1920 mutex_lock(&key_tfm_list_mutex);
1921 if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1922 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1924 printk(KERN_ERR "Error adding new key_tfm to list; "
1929 (*tfm) = key_tfm->key_tfm;
1930 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1932 mutex_unlock(&key_tfm_list_mutex);
1936 /* 64 characters forming a 6-bit target field */
1937 static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1940 "klmnopqrstuvwxyz");
1942 /* We could either offset on every reverse map or just pad some 0x00's
1943 * at the front here */
1944 static const unsigned char filename_rev_map[256] = {
1945 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1946 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1947 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1948 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1949 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1950 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1951 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1952 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1953 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1954 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1955 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1956 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1957 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1958 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1959 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
1960 0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */
1964 * ecryptfs_encode_for_filename
1965 * @dst: Destination location for encoded filename
1966 * @dst_size: Size of the encoded filename in bytes
1967 * @src: Source location for the filename to encode
1968 * @src_size: Size of the source in bytes
1970 static void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
1971 unsigned char *src, size_t src_size)
1974 size_t block_num = 0;
1975 size_t dst_offset = 0;
1976 unsigned char last_block[3];
1978 if (src_size == 0) {
1982 num_blocks = (src_size / 3);
1983 if ((src_size % 3) == 0) {
1984 memcpy(last_block, (&src[src_size - 3]), 3);
1987 last_block[2] = 0x00;
1988 switch (src_size % 3) {
1990 last_block[0] = src[src_size - 1];
1991 last_block[1] = 0x00;
1994 last_block[0] = src[src_size - 2];
1995 last_block[1] = src[src_size - 1];
1998 (*dst_size) = (num_blocks * 4);
2001 while (block_num < num_blocks) {
2002 unsigned char *src_block;
2003 unsigned char dst_block[4];
2005 if (block_num == (num_blocks - 1))
2006 src_block = last_block;
2008 src_block = &src[block_num * 3];
2009 dst_block[0] = ((src_block[0] >> 2) & 0x3F);
2010 dst_block[1] = (((src_block[0] << 4) & 0x30)
2011 | ((src_block[1] >> 4) & 0x0F));
2012 dst_block[2] = (((src_block[1] << 2) & 0x3C)
2013 | ((src_block[2] >> 6) & 0x03));
2014 dst_block[3] = (src_block[2] & 0x3F);
2015 dst[dst_offset++] = portable_filename_chars[dst_block[0]];
2016 dst[dst_offset++] = portable_filename_chars[dst_block[1]];
2017 dst[dst_offset++] = portable_filename_chars[dst_block[2]];
2018 dst[dst_offset++] = portable_filename_chars[dst_block[3]];
2025 static size_t ecryptfs_max_decoded_size(size_t encoded_size)
2027 /* Not exact; conservatively long. Every block of 4
2028 * encoded characters decodes into a block of 3
2029 * decoded characters. This segment of code provides
2030 * the caller with the maximum amount of allocated
2031 * space that @dst will need to point to in a
2032 * subsequent call. */
2033 return ((encoded_size + 1) * 3) / 4;
2037 * ecryptfs_decode_from_filename
2038 * @dst: If NULL, this function only sets @dst_size and returns. If
2039 * non-NULL, this function decodes the encoded octets in @src
2040 * into the memory that @dst points to.
2041 * @dst_size: Set to the size of the decoded string.
2042 * @src: The encoded set of octets to decode.
2043 * @src_size: The size of the encoded set of octets to decode.
2046 ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
2047 const unsigned char *src, size_t src_size)
2049 u8 current_bit_offset = 0;
2050 size_t src_byte_offset = 0;
2051 size_t dst_byte_offset = 0;
2054 (*dst_size) = ecryptfs_max_decoded_size(src_size);
2057 while (src_byte_offset < src_size) {
2058 unsigned char src_byte =
2059 filename_rev_map[(int)src[src_byte_offset]];
2061 switch (current_bit_offset) {
2063 dst[dst_byte_offset] = (src_byte << 2);
2064 current_bit_offset = 6;
2067 dst[dst_byte_offset++] |= (src_byte >> 4);
2068 dst[dst_byte_offset] = ((src_byte & 0xF)
2070 current_bit_offset = 4;
2073 dst[dst_byte_offset++] |= (src_byte >> 2);
2074 dst[dst_byte_offset] = (src_byte << 6);
2075 current_bit_offset = 2;
2078 dst[dst_byte_offset++] |= (src_byte);
2079 dst[dst_byte_offset] = 0;
2080 current_bit_offset = 0;
2085 (*dst_size) = dst_byte_offset;
2091 * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
2092 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
2093 * @name: The plaintext name
2094 * @length: The length of the plaintext
2095 * @encoded_name: The encypted name
2097 * Encrypts and encodes a filename into something that constitutes a
2098 * valid filename for a filesystem, with printable characters.
2100 * We assume that we have a properly initialized crypto context,
2101 * pointed to by crypt_stat->tfm.
2103 * Returns zero on success; non-zero on otherwise
2105 int ecryptfs_encrypt_and_encode_filename(
2106 char **encoded_name,
2107 size_t *encoded_name_size,
2108 struct ecryptfs_crypt_stat *crypt_stat,
2109 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2110 const char *name, size_t name_size)
2112 size_t encoded_name_no_prefix_size;
2115 (*encoded_name) = NULL;
2116 (*encoded_name_size) = 0;
2117 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
2118 || (mount_crypt_stat && (mount_crypt_stat->flags
2119 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) {
2120 struct ecryptfs_filename *filename;
2122 filename = kzalloc(sizeof(*filename), GFP_KERNEL);
2124 printk(KERN_ERR "%s: Out of memory whilst attempting "
2125 "to kzalloc [%zd] bytes\n", __func__,
2130 filename->filename = (char *)name;
2131 filename->filename_size = name_size;
2132 rc = ecryptfs_encrypt_filename(filename, crypt_stat,
2135 printk(KERN_ERR "%s: Error attempting to encrypt "
2136 "filename; rc = [%d]\n", __func__, rc);
2140 ecryptfs_encode_for_filename(
2141 NULL, &encoded_name_no_prefix_size,
2142 filename->encrypted_filename,
2143 filename->encrypted_filename_size);
2144 if ((crypt_stat && (crypt_stat->flags
2145 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2146 || (mount_crypt_stat
2147 && (mount_crypt_stat->flags
2148 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)))
2149 (*encoded_name_size) =
2150 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2151 + encoded_name_no_prefix_size);
2153 (*encoded_name_size) =
2154 (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2155 + encoded_name_no_prefix_size);
2156 (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
2157 if (!(*encoded_name)) {
2158 printk(KERN_ERR "%s: Out of memory whilst attempting "
2159 "to kzalloc [%zd] bytes\n", __func__,
2160 (*encoded_name_size));
2162 kfree(filename->encrypted_filename);
2166 if ((crypt_stat && (crypt_stat->flags
2167 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2168 || (mount_crypt_stat
2169 && (mount_crypt_stat->flags
2170 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
2171 memcpy((*encoded_name),
2172 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2173 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
2174 ecryptfs_encode_for_filename(
2176 + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
2177 &encoded_name_no_prefix_size,
2178 filename->encrypted_filename,
2179 filename->encrypted_filename_size);
2180 (*encoded_name_size) =
2181 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2182 + encoded_name_no_prefix_size);
2183 (*encoded_name)[(*encoded_name_size)] = '\0';
2188 printk(KERN_ERR "%s: Error attempting to encode "
2189 "encrypted filename; rc = [%d]\n", __func__,
2191 kfree((*encoded_name));
2192 (*encoded_name) = NULL;
2193 (*encoded_name_size) = 0;
2195 kfree(filename->encrypted_filename);
2198 rc = ecryptfs_copy_filename(encoded_name,
2207 * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
2208 * @plaintext_name: The plaintext name
2209 * @plaintext_name_size: The plaintext name size
2210 * @ecryptfs_dir_dentry: eCryptfs directory dentry
2211 * @name: The filename in cipher text
2212 * @name_size: The cipher text name size
2214 * Decrypts and decodes the filename.
2216 * Returns zero on error; non-zero otherwise
2218 int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
2219 size_t *plaintext_name_size,
2220 struct dentry *ecryptfs_dir_dentry,
2221 const char *name, size_t name_size)
2223 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2224 &ecryptfs_superblock_to_private(
2225 ecryptfs_dir_dentry->d_sb)->mount_crypt_stat;
2227 size_t decoded_name_size;
2231 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
2232 && !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
2233 && (name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
2234 && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2235 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
2236 const char *orig_name = name;
2237 size_t orig_name_size = name_size;
2239 name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2240 name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2241 ecryptfs_decode_from_filename(NULL, &decoded_name_size,
2243 decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
2244 if (!decoded_name) {
2245 printk(KERN_ERR "%s: Out of memory whilst attempting "
2246 "to kmalloc [%zd] bytes\n", __func__,
2251 ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
2253 rc = ecryptfs_parse_tag_70_packet(plaintext_name,
2254 plaintext_name_size,
2260 printk(KERN_INFO "%s: Could not parse tag 70 packet "
2261 "from filename; copying through filename "
2262 "as-is\n", __func__);
2263 rc = ecryptfs_copy_filename(plaintext_name,
2264 plaintext_name_size,
2265 orig_name, orig_name_size);
2269 rc = ecryptfs_copy_filename(plaintext_name,
2270 plaintext_name_size,
2275 kfree(decoded_name);
2280 #define ENC_NAME_MAX_BLOCKLEN_8_OR_16 143
2282 int ecryptfs_set_f_namelen(long *namelen, long lower_namelen,
2283 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
2285 struct blkcipher_desc desc;
2286 struct mutex *tfm_mutex;
2287 size_t cipher_blocksize;
2290 if (!(mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
2291 (*namelen) = lower_namelen;
2295 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
2296 mount_crypt_stat->global_default_fn_cipher_name);
2302 mutex_lock(tfm_mutex);
2303 cipher_blocksize = crypto_blkcipher_blocksize(desc.tfm);
2304 mutex_unlock(tfm_mutex);
2306 /* Return an exact amount for the common cases */
2307 if (lower_namelen == NAME_MAX
2308 && (cipher_blocksize == 8 || cipher_blocksize == 16)) {
2309 (*namelen) = ENC_NAME_MAX_BLOCKLEN_8_OR_16;
2313 /* Return a safe estimate for the uncommon cases */
2314 (*namelen) = lower_namelen;
2315 (*namelen) -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2316 /* Since this is the max decoded size, subtract 1 "decoded block" len */
2317 (*namelen) = ecryptfs_max_decoded_size(*namelen) - 3;
2318 (*namelen) -= ECRYPTFS_TAG_70_MAX_METADATA_SIZE;
2319 (*namelen) -= ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES;
2320 /* Worst case is that the filename is padded nearly a full block size */
2321 (*namelen) -= cipher_blocksize - 1;