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, int dst_offset,
43 struct page *src_page, int src_offset, int size,
46 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
47 struct page *dst_page, int dst_offset,
48 struct page *src_page, int src_offset, int size,
53 * @dst: Buffer to take hex character representation of contents of
54 * src; must be at least of size (src_size * 2)
55 * @src: Buffer to be converted to a hex string respresentation
56 * @src_size: number of bytes to convert
58 void ecryptfs_to_hex(char *dst, char *src, size_t src_size)
62 for (x = 0; x < src_size; x++)
63 sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]);
68 * @dst: Buffer to take the bytes from src hex; must be at least of
70 * @src: Buffer to be converted from a hex string respresentation to raw value
71 * @dst_size: size of dst buffer, or number of hex characters pairs to convert
73 void ecryptfs_from_hex(char *dst, char *src, int dst_size)
78 for (x = 0; x < dst_size; x++) {
80 tmp[1] = src[x * 2 + 1];
81 dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
86 * ecryptfs_calculate_md5 - calculates the md5 of @src
87 * @dst: Pointer to 16 bytes of allocated memory
88 * @crypt_stat: Pointer to crypt_stat struct for the current inode
89 * @src: Data to be md5'd
90 * @len: Length of @src
92 * Uses the allocated crypto context that crypt_stat references to
93 * generate the MD5 sum of the contents of src.
95 static int ecryptfs_calculate_md5(char *dst,
96 struct ecryptfs_crypt_stat *crypt_stat,
99 struct scatterlist sg;
100 struct hash_desc desc = {
101 .tfm = crypt_stat->hash_tfm,
102 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
106 mutex_lock(&crypt_stat->cs_hash_tfm_mutex);
107 sg_init_one(&sg, (u8 *)src, len);
109 desc.tfm = crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH, 0,
111 if (IS_ERR(desc.tfm)) {
112 rc = PTR_ERR(desc.tfm);
113 ecryptfs_printk(KERN_ERR, "Error attempting to "
114 "allocate crypto context; rc = [%d]\n",
118 crypt_stat->hash_tfm = desc.tfm;
120 rc = crypto_hash_init(&desc);
123 "%s: Error initializing crypto hash; rc = [%d]\n",
127 rc = crypto_hash_update(&desc, &sg, len);
130 "%s: Error updating crypto hash; rc = [%d]\n",
134 rc = crypto_hash_final(&desc, dst);
137 "%s: Error finalizing crypto hash; rc = [%d]\n",
142 mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
146 static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
148 char *chaining_modifier)
150 int cipher_name_len = strlen(cipher_name);
151 int chaining_modifier_len = strlen(chaining_modifier);
152 int algified_name_len;
155 algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
156 (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
157 if (!(*algified_name)) {
161 snprintf((*algified_name), algified_name_len, "%s(%s)",
162 chaining_modifier, cipher_name);
170 * @iv: destination for the derived iv vale
171 * @crypt_stat: Pointer to crypt_stat struct for the current inode
172 * @offset: Offset of the extent whose IV we are to derive
174 * Generate the initialization vector from the given root IV and page
177 * Returns zero on success; non-zero on error.
179 int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
183 char dst[MD5_DIGEST_SIZE];
184 char src[ECRYPTFS_MAX_IV_BYTES + 16];
186 if (unlikely(ecryptfs_verbosity > 0)) {
187 ecryptfs_printk(KERN_DEBUG, "root iv:\n");
188 ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
190 /* TODO: It is probably secure to just cast the least
191 * significant bits of the root IV into an unsigned long and
192 * add the offset to that rather than go through all this
193 * hashing business. -Halcrow */
194 memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
195 memset((src + crypt_stat->iv_bytes), 0, 16);
196 snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
197 if (unlikely(ecryptfs_verbosity > 0)) {
198 ecryptfs_printk(KERN_DEBUG, "source:\n");
199 ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
201 rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
202 (crypt_stat->iv_bytes + 16));
204 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
205 "MD5 while generating IV for a page\n");
208 memcpy(iv, dst, crypt_stat->iv_bytes);
209 if (unlikely(ecryptfs_verbosity > 0)) {
210 ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
211 ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
218 * ecryptfs_init_crypt_stat
219 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
221 * Initialize the crypt_stat structure.
224 ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
226 memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
227 INIT_LIST_HEAD(&crypt_stat->keysig_list);
228 mutex_init(&crypt_stat->keysig_list_mutex);
229 mutex_init(&crypt_stat->cs_mutex);
230 mutex_init(&crypt_stat->cs_tfm_mutex);
231 mutex_init(&crypt_stat->cs_hash_tfm_mutex);
232 crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
236 * ecryptfs_destroy_crypt_stat
237 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
239 * Releases all memory associated with a crypt_stat struct.
241 void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
243 struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
246 crypto_free_ablkcipher(crypt_stat->tfm);
247 if (crypt_stat->hash_tfm)
248 crypto_free_hash(crypt_stat->hash_tfm);
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 memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
257 void ecryptfs_destroy_mount_crypt_stat(
258 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
260 struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
262 if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
264 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
265 list_for_each_entry_safe(auth_tok, auth_tok_tmp,
266 &mount_crypt_stat->global_auth_tok_list,
267 mount_crypt_stat_list) {
268 list_del(&auth_tok->mount_crypt_stat_list);
269 if (auth_tok->global_auth_tok_key
270 && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
271 key_put(auth_tok->global_auth_tok_key);
272 kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
274 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
275 memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
279 * virt_to_scatterlist
280 * @addr: Virtual address
281 * @size: Size of data; should be an even multiple of the block size
282 * @sg: Pointer to scatterlist array; set to NULL to obtain only
283 * the number of scatterlist structs required in array
284 * @sg_size: Max array size
286 * Fills in a scatterlist array with page references for a passed
289 * Returns the number of scatterlist structs in array used
291 int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
297 int remainder_of_page;
299 sg_init_table(sg, sg_size);
301 while (size > 0 && i < sg_size) {
302 pg = virt_to_page(addr);
303 offset = offset_in_page(addr);
304 sg_set_page(&sg[i], pg, 0, offset);
305 remainder_of_page = PAGE_CACHE_SIZE - offset;
306 if (size >= remainder_of_page) {
307 sg[i].length = remainder_of_page;
308 addr += remainder_of_page;
309 size -= remainder_of_page;
322 struct extent_crypt_result {
323 struct completion completion;
327 static void extent_crypt_complete(struct crypto_async_request *req, int rc)
329 struct extent_crypt_result *ecr = req->data;
331 if (rc == -EINPROGRESS)
335 complete(&ecr->completion);
339 * encrypt_scatterlist
340 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
341 * @dest_sg: Destination of encrypted data
342 * @src_sg: Data to be encrypted
343 * @size: Length of data to be encrypted
344 * @iv: iv to use during encryption
346 * Returns the number of bytes encrypted; negative value on error
348 static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
349 struct scatterlist *dest_sg,
350 struct scatterlist *src_sg, int size,
353 struct ablkcipher_request *req = NULL;
354 struct extent_crypt_result ecr;
357 BUG_ON(!crypt_stat || !crypt_stat->tfm
358 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
359 if (unlikely(ecryptfs_verbosity > 0)) {
360 ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
361 crypt_stat->key_size);
362 ecryptfs_dump_hex(crypt_stat->key,
363 crypt_stat->key_size);
366 init_completion(&ecr.completion);
368 mutex_lock(&crypt_stat->cs_tfm_mutex);
369 req = ablkcipher_request_alloc(crypt_stat->tfm, GFP_NOFS);
371 mutex_unlock(&crypt_stat->cs_tfm_mutex);
376 ablkcipher_request_set_callback(req,
377 CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
378 extent_crypt_complete, &ecr);
379 /* Consider doing this once, when the file is opened */
380 if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
381 rc = crypto_ablkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
382 crypt_stat->key_size);
384 ecryptfs_printk(KERN_ERR,
385 "Error setting key; rc = [%d]\n",
387 mutex_unlock(&crypt_stat->cs_tfm_mutex);
391 crypt_stat->flags |= ECRYPTFS_KEY_SET;
393 mutex_unlock(&crypt_stat->cs_tfm_mutex);
394 ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size);
395 ablkcipher_request_set_crypt(req, src_sg, dest_sg, size, iv);
396 rc = crypto_ablkcipher_encrypt(req);
397 if (rc == -EINPROGRESS || rc == -EBUSY) {
398 struct extent_crypt_result *ecr = req->base.data;
400 wait_for_completion(&ecr->completion);
402 INIT_COMPLETION(ecr->completion);
405 ablkcipher_request_free(req);
410 * ecryptfs_lower_offset_for_extent
412 * Convert an eCryptfs page index into a lower byte offset
414 static void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
415 struct ecryptfs_crypt_stat *crypt_stat)
417 (*offset) = ecryptfs_lower_header_size(crypt_stat)
418 + (crypt_stat->extent_size * extent_num);
422 * ecryptfs_encrypt_extent
423 * @enc_extent_page: Allocated page into which to encrypt the data in
425 * @crypt_stat: crypt_stat containing cryptographic context for the
426 * encryption operation
427 * @page: Page containing plaintext data extent to encrypt
428 * @extent_offset: Page extent offset for use in generating IV
430 * Encrypts one extent of data.
432 * Return zero on success; non-zero otherwise
434 static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
435 struct ecryptfs_crypt_stat *crypt_stat,
437 unsigned long extent_offset)
440 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
443 extent_base = (((loff_t)page->index)
444 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
445 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
446 (extent_base + extent_offset));
448 ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
449 "extent [0x%.16llx]; rc = [%d]\n",
450 (unsigned long long)(extent_base + extent_offset), rc);
453 rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page,
454 extent_offset * crypt_stat->extent_size,
456 extent_offset * crypt_stat->extent_size,
457 crypt_stat->extent_size, extent_iv);
459 printk(KERN_ERR "%s: Error attempting to encrypt page with "
460 "page->index = [%ld], extent_offset = [%ld]; "
461 "rc = [%d]\n", __func__, page->index, extent_offset,
471 * ecryptfs_encrypt_page
472 * @page: Page mapped from the eCryptfs inode for the file; contains
473 * decrypted content that needs to be encrypted (to a temporary
474 * page; not in place) and written out to the lower file
476 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
477 * that eCryptfs pages may straddle the lower pages -- for instance,
478 * if the file was created on a machine with an 8K page size
479 * (resulting in an 8K header), and then the file is copied onto a
480 * host with a 32K page size, then when reading page 0 of the eCryptfs
481 * file, 24K of page 0 of the lower file will be read and decrypted,
482 * and then 8K of page 1 of the lower file will be read and decrypted.
484 * Returns zero on success; negative on error
486 int ecryptfs_encrypt_page(struct page *page)
488 struct inode *ecryptfs_inode;
489 struct ecryptfs_crypt_stat *crypt_stat;
490 char *enc_extent_virt;
491 struct page *enc_extent_page = NULL;
492 loff_t extent_offset;
496 ecryptfs_inode = page->mapping->host;
498 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
499 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
500 enc_extent_page = alloc_page(GFP_USER);
501 if (!enc_extent_page) {
503 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
504 "encrypted extent\n");
508 for (extent_offset = 0;
509 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
511 rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
514 printk(KERN_ERR "%s: Error encrypting extent; "
515 "rc = [%d]\n", __func__, rc);
520 ecryptfs_lower_offset_for_extent(&lower_offset,
521 page->index * (PAGE_CACHE_SIZE / crypt_stat->extent_size),
523 enc_extent_virt = kmap(enc_extent_page);
524 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset,
526 kunmap(enc_extent_page);
528 ecryptfs_printk(KERN_ERR,
529 "Error attempting to write lower page; rc = [%d]\n",
535 if (enc_extent_page) {
536 __free_page(enc_extent_page);
541 static int ecryptfs_decrypt_extent(struct page *page,
542 struct ecryptfs_crypt_stat *crypt_stat,
543 struct page *enc_extent_page,
544 unsigned long extent_offset)
547 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
550 extent_base = (((loff_t)page->index)
551 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
552 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
553 (extent_base + extent_offset));
555 ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
556 "extent [0x%.16llx]; rc = [%d]\n",
557 (unsigned long long)(extent_base + extent_offset), rc);
560 rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
561 extent_offset * crypt_stat->extent_size,
563 extent_offset * crypt_stat->extent_size,
564 crypt_stat->extent_size, extent_iv);
566 printk(KERN_ERR "%s: Error attempting to decrypt to page with "
567 "page->index = [%ld], extent_offset = [%ld]; "
568 "rc = [%d]\n", __func__, page->index, extent_offset,
578 * ecryptfs_decrypt_page
579 * @page: Page mapped from the eCryptfs inode for the file; data read
580 * and decrypted from the lower file will be written into this
583 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
584 * that eCryptfs pages may straddle the lower pages -- for instance,
585 * if the file was created on a machine with an 8K page size
586 * (resulting in an 8K header), and then the file is copied onto a
587 * host with a 32K page size, then when reading page 0 of the eCryptfs
588 * file, 24K of page 0 of the lower file will be read and decrypted,
589 * and then 8K of page 1 of the lower file will be read and decrypted.
591 * Returns zero on success; negative on error
593 int ecryptfs_decrypt_page(struct page *page)
595 struct inode *ecryptfs_inode;
596 struct ecryptfs_crypt_stat *crypt_stat;
597 char *enc_extent_virt;
598 struct page *enc_extent_page = NULL;
599 unsigned long extent_offset;
603 ecryptfs_inode = page->mapping->host;
605 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
606 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
607 enc_extent_page = alloc_page(GFP_USER);
608 if (!enc_extent_page) {
610 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
611 "encrypted extent\n");
615 ecryptfs_lower_offset_for_extent(&lower_offset,
616 page->index * (PAGE_CACHE_SIZE / crypt_stat->extent_size),
618 enc_extent_virt = kmap(enc_extent_page);
619 rc = ecryptfs_read_lower(enc_extent_virt, lower_offset, PAGE_CACHE_SIZE,
621 kunmap(enc_extent_page);
623 ecryptfs_printk(KERN_ERR,
624 "Error attempting to read lower page; rc = [%d]\n",
629 for (extent_offset = 0;
630 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
632 rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
635 printk(KERN_ERR "%s: Error encrypting extent; "
636 "rc = [%d]\n", __func__, rc);
641 if (enc_extent_page) {
642 __free_page(enc_extent_page);
648 * decrypt_scatterlist
649 * @crypt_stat: Cryptographic context
650 * @dest_sg: The destination scatterlist to decrypt into
651 * @src_sg: The source scatterlist to decrypt from
652 * @size: The number of bytes to decrypt
653 * @iv: The initialization vector to use for the decryption
655 * Returns the number of bytes decrypted; negative value on error
657 static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
658 struct scatterlist *dest_sg,
659 struct scatterlist *src_sg, int size,
662 struct ablkcipher_request *req = NULL;
663 struct extent_crypt_result ecr;
666 BUG_ON(!crypt_stat || !crypt_stat->tfm
667 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
668 if (unlikely(ecryptfs_verbosity > 0)) {
669 ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
670 crypt_stat->key_size);
671 ecryptfs_dump_hex(crypt_stat->key,
672 crypt_stat->key_size);
675 init_completion(&ecr.completion);
677 mutex_lock(&crypt_stat->cs_tfm_mutex);
678 req = ablkcipher_request_alloc(crypt_stat->tfm, GFP_NOFS);
680 mutex_unlock(&crypt_stat->cs_tfm_mutex);
685 ablkcipher_request_set_callback(req,
686 CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
687 extent_crypt_complete, &ecr);
688 /* Consider doing this once, when the file is opened */
689 if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
690 rc = crypto_ablkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
691 crypt_stat->key_size);
693 ecryptfs_printk(KERN_ERR,
694 "Error setting key; rc = [%d]\n",
696 mutex_unlock(&crypt_stat->cs_tfm_mutex);
700 crypt_stat->flags |= ECRYPTFS_KEY_SET;
702 mutex_unlock(&crypt_stat->cs_tfm_mutex);
703 ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
704 ablkcipher_request_set_crypt(req, src_sg, dest_sg, size, iv);
705 rc = crypto_ablkcipher_decrypt(req);
706 if (rc == -EINPROGRESS || rc == -EBUSY) {
707 struct extent_crypt_result *ecr = req->base.data;
709 wait_for_completion(&ecr->completion);
711 INIT_COMPLETION(ecr->completion);
714 ablkcipher_request_free(req);
720 * ecryptfs_encrypt_page_offset
721 * @crypt_stat: The cryptographic context
722 * @dst_page: The page to encrypt into
723 * @dst_offset: The offset in the page to encrypt into
724 * @src_page: The page to encrypt from
725 * @src_offset: The offset in the page to encrypt from
726 * @size: The number of bytes to encrypt
727 * @iv: The initialization vector to use for the encryption
729 * Returns the number of bytes encrypted
732 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
733 struct page *dst_page, int dst_offset,
734 struct page *src_page, int src_offset, int size,
737 struct scatterlist src_sg, dst_sg;
739 sg_init_table(&src_sg, 1);
740 sg_init_table(&dst_sg, 1);
742 sg_set_page(&src_sg, src_page, size, src_offset);
743 sg_set_page(&dst_sg, dst_page, size, dst_offset);
744 return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
748 * ecryptfs_decrypt_page_offset
749 * @crypt_stat: The cryptographic context
750 * @dst_page: The page to decrypt into
751 * @dst_offset: The offset in the page to decrypt into
752 * @src_page: The page to decrypt from
753 * @src_offset: The offset in the page to decrypt from
754 * @size: The number of bytes to decrypt
755 * @iv: The initialization vector to use for the decryption
757 * Returns the number of bytes decrypted
760 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
761 struct page *dst_page, int dst_offset,
762 struct page *src_page, int src_offset, int size,
765 struct scatterlist src_sg, dst_sg;
767 sg_init_table(&src_sg, 1);
768 sg_set_page(&src_sg, src_page, size, src_offset);
770 sg_init_table(&dst_sg, 1);
771 sg_set_page(&dst_sg, dst_page, size, dst_offset);
773 return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
776 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
779 * ecryptfs_init_crypt_ctx
780 * @crypt_stat: Uninitialized crypt stats structure
782 * Initialize the crypto context.
784 * TODO: Performance: Keep a cache of initialized cipher contexts;
785 * only init if needed
787 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
792 if (!crypt_stat->cipher) {
793 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
796 ecryptfs_printk(KERN_DEBUG,
797 "Initializing cipher [%s]; strlen = [%d]; "
798 "key_size_bits = [%zd]\n",
799 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
800 crypt_stat->key_size << 3);
801 if (crypt_stat->tfm) {
805 mutex_lock(&crypt_stat->cs_tfm_mutex);
806 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
807 crypt_stat->cipher, "cbc");
810 crypt_stat->tfm = crypto_alloc_ablkcipher(full_alg_name, 0, 0);
811 kfree(full_alg_name);
812 if (IS_ERR(crypt_stat->tfm)) {
813 rc = PTR_ERR(crypt_stat->tfm);
814 crypt_stat->tfm = NULL;
815 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
816 "Error initializing cipher [%s]\n",
820 crypto_ablkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
823 mutex_unlock(&crypt_stat->cs_tfm_mutex);
828 static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
832 crypt_stat->extent_mask = 0xFFFFFFFF;
833 crypt_stat->extent_shift = 0;
834 if (crypt_stat->extent_size == 0)
836 extent_size_tmp = crypt_stat->extent_size;
837 while ((extent_size_tmp & 0x01) == 0) {
838 extent_size_tmp >>= 1;
839 crypt_stat->extent_mask <<= 1;
840 crypt_stat->extent_shift++;
844 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
846 /* Default values; may be overwritten as we are parsing the
848 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
849 set_extent_mask_and_shift(crypt_stat);
850 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
851 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
852 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
854 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
855 crypt_stat->metadata_size =
856 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
858 crypt_stat->metadata_size = PAGE_CACHE_SIZE;
863 * ecryptfs_compute_root_iv
866 * On error, sets the root IV to all 0's.
868 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
871 char dst[MD5_DIGEST_SIZE];
873 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
874 BUG_ON(crypt_stat->iv_bytes <= 0);
875 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
877 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
878 "cannot generate root IV\n");
881 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
882 crypt_stat->key_size);
884 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
885 "MD5 while generating root IV\n");
888 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
891 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
892 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
897 static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
899 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
900 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
901 ecryptfs_compute_root_iv(crypt_stat);
902 if (unlikely(ecryptfs_verbosity > 0)) {
903 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
904 ecryptfs_dump_hex(crypt_stat->key,
905 crypt_stat->key_size);
910 * ecryptfs_copy_mount_wide_flags_to_inode_flags
911 * @crypt_stat: The inode's cryptographic context
912 * @mount_crypt_stat: The mount point's cryptographic context
914 * This function propagates the mount-wide flags to individual inode
917 static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
918 struct ecryptfs_crypt_stat *crypt_stat,
919 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
921 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
922 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
923 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
924 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
925 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
926 crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
927 if (mount_crypt_stat->flags
928 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
929 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
930 else if (mount_crypt_stat->flags
931 & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
932 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
936 static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
937 struct ecryptfs_crypt_stat *crypt_stat,
938 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
940 struct ecryptfs_global_auth_tok *global_auth_tok;
943 mutex_lock(&crypt_stat->keysig_list_mutex);
944 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
946 list_for_each_entry(global_auth_tok,
947 &mount_crypt_stat->global_auth_tok_list,
948 mount_crypt_stat_list) {
949 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
951 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
953 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
959 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
960 mutex_unlock(&crypt_stat->keysig_list_mutex);
965 * ecryptfs_set_default_crypt_stat_vals
966 * @crypt_stat: The inode's cryptographic context
967 * @mount_crypt_stat: The mount point's cryptographic context
969 * Default values in the event that policy does not override them.
971 static void ecryptfs_set_default_crypt_stat_vals(
972 struct ecryptfs_crypt_stat *crypt_stat,
973 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
975 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
977 ecryptfs_set_default_sizes(crypt_stat);
978 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
979 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
980 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
981 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
982 crypt_stat->mount_crypt_stat = mount_crypt_stat;
986 * ecryptfs_new_file_context
987 * @ecryptfs_inode: The eCryptfs inode
989 * If the crypto context for the file has not yet been established,
990 * this is where we do that. Establishing a new crypto context
991 * involves the following decisions:
992 * - What cipher to use?
993 * - What set of authentication tokens to use?
994 * Here we just worry about getting enough information into the
995 * authentication tokens so that we know that they are available.
996 * We associate the available authentication tokens with the new file
997 * via the set of signatures in the crypt_stat struct. Later, when
998 * the headers are actually written out, we may again defer to
999 * userspace to perform the encryption of the session key; for the
1000 * foreseeable future, this will be the case with public key packets.
1002 * Returns zero on success; non-zero otherwise
1004 int ecryptfs_new_file_context(struct inode *ecryptfs_inode)
1006 struct ecryptfs_crypt_stat *crypt_stat =
1007 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1008 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1009 &ecryptfs_superblock_to_private(
1010 ecryptfs_inode->i_sb)->mount_crypt_stat;
1011 int cipher_name_len;
1014 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
1015 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
1016 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1018 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
1021 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
1022 "to the inode key sigs; rc = [%d]\n", rc);
1026 strlen(mount_crypt_stat->global_default_cipher_name);
1027 memcpy(crypt_stat->cipher,
1028 mount_crypt_stat->global_default_cipher_name,
1030 crypt_stat->cipher[cipher_name_len] = '\0';
1031 crypt_stat->key_size =
1032 mount_crypt_stat->global_default_cipher_key_size;
1033 ecryptfs_generate_new_key(crypt_stat);
1034 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1036 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
1037 "context for cipher [%s]: rc = [%d]\n",
1038 crypt_stat->cipher, rc);
1044 * ecryptfs_validate_marker - check for the ecryptfs marker
1045 * @data: The data block in which to check
1047 * Returns zero if marker found; -EINVAL if not found
1049 static int ecryptfs_validate_marker(char *data)
1053 m_1 = get_unaligned_be32(data);
1054 m_2 = get_unaligned_be32(data + 4);
1055 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
1057 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1058 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1059 MAGIC_ECRYPTFS_MARKER);
1060 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1061 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1065 struct ecryptfs_flag_map_elem {
1070 /* Add support for additional flags by adding elements here. */
1071 static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1072 {0x00000001, ECRYPTFS_ENABLE_HMAC},
1073 {0x00000002, ECRYPTFS_ENCRYPTED},
1074 {0x00000004, ECRYPTFS_METADATA_IN_XATTR},
1075 {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
1079 * ecryptfs_process_flags
1080 * @crypt_stat: The cryptographic context
1081 * @page_virt: Source data to be parsed
1082 * @bytes_read: Updated with the number of bytes read
1084 * Returns zero on success; non-zero if the flag set is invalid
1086 static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1087 char *page_virt, int *bytes_read)
1093 flags = get_unaligned_be32(page_virt);
1094 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1095 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1096 if (flags & ecryptfs_flag_map[i].file_flag) {
1097 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
1099 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
1100 /* Version is in top 8 bits of the 32-bit flag vector */
1101 crypt_stat->file_version = ((flags >> 24) & 0xFF);
1107 * write_ecryptfs_marker
1108 * @page_virt: The pointer to in a page to begin writing the marker
1109 * @written: Number of bytes written
1111 * Marker = 0x3c81b7f5
1113 static void write_ecryptfs_marker(char *page_virt, size_t *written)
1117 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1118 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
1119 put_unaligned_be32(m_1, page_virt);
1120 page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
1121 put_unaligned_be32(m_2, page_virt);
1122 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1125 void ecryptfs_write_crypt_stat_flags(char *page_virt,
1126 struct ecryptfs_crypt_stat *crypt_stat,
1132 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1133 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1134 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
1135 flags |= ecryptfs_flag_map[i].file_flag;
1136 /* Version is in top 8 bits of the 32-bit flag vector */
1137 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
1138 put_unaligned_be32(flags, page_virt);
1142 struct ecryptfs_cipher_code_str_map_elem {
1143 char cipher_str[16];
1147 /* Add support for additional ciphers by adding elements here. The
1148 * cipher_code is whatever OpenPGP applicatoins use to identify the
1149 * ciphers. List in order of probability. */
1150 static struct ecryptfs_cipher_code_str_map_elem
1151 ecryptfs_cipher_code_str_map[] = {
1152 {"aes",RFC2440_CIPHER_AES_128 },
1153 {"blowfish", RFC2440_CIPHER_BLOWFISH},
1154 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1155 {"cast5", RFC2440_CIPHER_CAST_5},
1156 {"twofish", RFC2440_CIPHER_TWOFISH},
1157 {"cast6", RFC2440_CIPHER_CAST_6},
1158 {"aes", RFC2440_CIPHER_AES_192},
1159 {"aes", RFC2440_CIPHER_AES_256}
1163 * ecryptfs_code_for_cipher_string
1164 * @cipher_name: The string alias for the cipher
1165 * @key_bytes: Length of key in bytes; used for AES code selection
1167 * Returns zero on no match, or the cipher code on match
1169 u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
1173 struct ecryptfs_cipher_code_str_map_elem *map =
1174 ecryptfs_cipher_code_str_map;
1176 if (strcmp(cipher_name, "aes") == 0) {
1177 switch (key_bytes) {
1179 code = RFC2440_CIPHER_AES_128;
1182 code = RFC2440_CIPHER_AES_192;
1185 code = RFC2440_CIPHER_AES_256;
1188 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1189 if (strcmp(cipher_name, map[i].cipher_str) == 0) {
1190 code = map[i].cipher_code;
1198 * ecryptfs_cipher_code_to_string
1199 * @str: Destination to write out the cipher name
1200 * @cipher_code: The code to convert to cipher name string
1202 * Returns zero on success
1204 int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
1210 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1211 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1212 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1213 if (str[0] == '\0') {
1214 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1215 "[%d]\n", cipher_code);
1221 int ecryptfs_read_and_validate_header_region(struct inode *inode)
1223 u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1224 u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
1227 rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES,
1229 if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1230 return rc >= 0 ? -EINVAL : rc;
1231 rc = ecryptfs_validate_marker(marker);
1233 ecryptfs_i_size_init(file_size, inode);
1238 ecryptfs_write_header_metadata(char *virt,
1239 struct ecryptfs_crypt_stat *crypt_stat,
1242 u32 header_extent_size;
1243 u16 num_header_extents_at_front;
1245 header_extent_size = (u32)crypt_stat->extent_size;
1246 num_header_extents_at_front =
1247 (u16)(crypt_stat->metadata_size / crypt_stat->extent_size);
1248 put_unaligned_be32(header_extent_size, virt);
1250 put_unaligned_be16(num_header_extents_at_front, virt);
1254 struct kmem_cache *ecryptfs_header_cache;
1257 * ecryptfs_write_headers_virt
1258 * @page_virt: The virtual address to write the headers to
1259 * @max: The size of memory allocated at page_virt
1260 * @size: Set to the number of bytes written by this function
1261 * @crypt_stat: The cryptographic context
1262 * @ecryptfs_dentry: The eCryptfs dentry
1267 * Octets 0-7: Unencrypted file size (big-endian)
1268 * Octets 8-15: eCryptfs special marker
1269 * Octets 16-19: Flags
1270 * Octet 16: File format version number (between 0 and 255)
1271 * Octets 17-18: Reserved
1272 * Octet 19: Bit 1 (lsb): Reserved
1274 * Bits 3-8: Reserved
1275 * Octets 20-23: Header extent size (big-endian)
1276 * Octets 24-25: Number of header extents at front of file
1278 * Octet 26: Begin RFC 2440 authentication token packet set
1280 * Lower data (CBC encrypted)
1282 * Lower data (CBC encrypted)
1285 * Returns zero on success
1287 static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1289 struct ecryptfs_crypt_stat *crypt_stat,
1290 struct dentry *ecryptfs_dentry)
1296 offset = ECRYPTFS_FILE_SIZE_BYTES;
1297 write_ecryptfs_marker((page_virt + offset), &written);
1299 ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat,
1302 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1305 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1306 ecryptfs_dentry, &written,
1309 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1310 "set; rc = [%d]\n", rc);
1319 ecryptfs_write_metadata_to_contents(struct inode *ecryptfs_inode,
1320 char *virt, size_t virt_len)
1324 rc = ecryptfs_write_lower(ecryptfs_inode, virt,
1327 printk(KERN_ERR "%s: Error attempting to write header "
1328 "information to lower file; rc = [%d]\n", __func__, rc);
1335 ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1336 char *page_virt, size_t size)
1340 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1345 static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1350 page = alloc_pages(gfp_mask | __GFP_ZERO, order);
1352 return (unsigned long) page_address(page);
1357 * ecryptfs_write_metadata
1358 * @ecryptfs_dentry: The eCryptfs dentry, which should be negative
1359 * @ecryptfs_inode: The newly created eCryptfs inode
1361 * Write the file headers out. This will likely involve a userspace
1362 * callout, in which the session key is encrypted with one or more
1363 * public keys and/or the passphrase necessary to do the encryption is
1364 * retrieved via a prompt. Exactly what happens at this point should
1365 * be policy-dependent.
1367 * Returns zero on success; non-zero on error
1369 int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
1370 struct inode *ecryptfs_inode)
1372 struct ecryptfs_crypt_stat *crypt_stat =
1373 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1380 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1381 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
1382 printk(KERN_ERR "Key is invalid; bailing out\n");
1387 printk(KERN_WARNING "%s: Encrypted flag not set\n",
1392 virt_len = crypt_stat->metadata_size;
1393 order = get_order(virt_len);
1394 /* Released in this function */
1395 virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
1397 printk(KERN_ERR "%s: Out of memory\n", __func__);
1401 /* Zeroed page ensures the in-header unencrypted i_size is set to 0 */
1402 rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
1405 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
1409 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1410 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt,
1413 rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt,
1416 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
1417 "rc = [%d]\n", __func__, rc);
1421 free_pages((unsigned long)virt, order);
1426 #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1427 #define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1428 static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
1429 char *virt, int *bytes_read,
1430 int validate_header_size)
1433 u32 header_extent_size;
1434 u16 num_header_extents_at_front;
1436 header_extent_size = get_unaligned_be32(virt);
1437 virt += sizeof(__be32);
1438 num_header_extents_at_front = get_unaligned_be16(virt);
1439 crypt_stat->metadata_size = (((size_t)num_header_extents_at_front
1440 * (size_t)header_extent_size));
1441 (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
1442 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
1443 && (crypt_stat->metadata_size
1444 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
1446 printk(KERN_WARNING "Invalid header size: [%zd]\n",
1447 crypt_stat->metadata_size);
1453 * set_default_header_data
1454 * @crypt_stat: The cryptographic context
1456 * For version 0 file format; this function is only for backwards
1457 * compatibility for files created with the prior versions of
1460 static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1462 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
1465 void ecryptfs_i_size_init(const char *page_virt, struct inode *inode)
1467 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1468 struct ecryptfs_crypt_stat *crypt_stat;
1471 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
1473 &ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat;
1474 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
1475 file_size = i_size_read(ecryptfs_inode_to_lower(inode));
1476 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1477 file_size += crypt_stat->metadata_size;
1479 file_size = get_unaligned_be64(page_virt);
1480 i_size_write(inode, (loff_t)file_size);
1481 crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED;
1485 * ecryptfs_read_headers_virt
1486 * @page_virt: The virtual address into which to read the headers
1487 * @crypt_stat: The cryptographic context
1488 * @ecryptfs_dentry: The eCryptfs dentry
1489 * @validate_header_size: Whether to validate the header size while reading
1491 * Read/parse the header data. The header format is detailed in the
1492 * comment block for the ecryptfs_write_headers_virt() function.
1494 * Returns zero on success
1496 static int ecryptfs_read_headers_virt(char *page_virt,
1497 struct ecryptfs_crypt_stat *crypt_stat,
1498 struct dentry *ecryptfs_dentry,
1499 int validate_header_size)
1505 ecryptfs_set_default_sizes(crypt_stat);
1506 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1507 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1508 offset = ECRYPTFS_FILE_SIZE_BYTES;
1509 rc = ecryptfs_validate_marker(page_virt + offset);
1512 if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED))
1513 ecryptfs_i_size_init(page_virt, ecryptfs_dentry->d_inode);
1514 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1515 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1518 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1521 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1522 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1523 "file version [%d] is supported by this "
1524 "version of eCryptfs\n",
1525 crypt_stat->file_version,
1526 ECRYPTFS_SUPPORTED_FILE_VERSION);
1530 offset += bytes_read;
1531 if (crypt_stat->file_version >= 1) {
1532 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
1533 &bytes_read, validate_header_size);
1535 ecryptfs_printk(KERN_WARNING, "Error reading header "
1536 "metadata; rc = [%d]\n", rc);
1538 offset += bytes_read;
1540 set_default_header_data(crypt_stat);
1541 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1548 * ecryptfs_read_xattr_region
1549 * @page_virt: The vitual address into which to read the xattr data
1550 * @ecryptfs_inode: The eCryptfs inode
1552 * Attempts to read the crypto metadata from the extended attribute
1553 * region of the lower file.
1555 * Returns zero on success; non-zero on error
1557 int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
1559 struct dentry *lower_dentry =
1560 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
1564 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1565 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
1567 if (unlikely(ecryptfs_verbosity > 0))
1568 printk(KERN_INFO "Error attempting to read the [%s] "
1569 "xattr from the lower file; return value = "
1570 "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
1578 int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
1579 struct inode *inode)
1581 u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1582 u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
1585 rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1586 ECRYPTFS_XATTR_NAME, file_size,
1587 ECRYPTFS_SIZE_AND_MARKER_BYTES);
1588 if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1589 return rc >= 0 ? -EINVAL : rc;
1590 rc = ecryptfs_validate_marker(marker);
1592 ecryptfs_i_size_init(file_size, inode);
1597 * ecryptfs_read_metadata
1599 * Common entry point for reading file metadata. From here, we could
1600 * retrieve the header information from the header region of the file,
1601 * the xattr region of the file, or some other repostory that is
1602 * stored separately from the file itself. The current implementation
1603 * supports retrieving the metadata information from the file contents
1604 * and from the xattr region.
1606 * Returns zero if valid headers found and parsed; non-zero otherwise
1608 int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
1612 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
1613 struct ecryptfs_crypt_stat *crypt_stat =
1614 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1615 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1616 &ecryptfs_superblock_to_private(
1617 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1619 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1621 /* Read the first page from the underlying file */
1622 page_virt = kmem_cache_alloc(ecryptfs_header_cache, GFP_USER);
1625 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
1629 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1632 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1634 ECRYPTFS_VALIDATE_HEADER_SIZE);
1636 /* metadata is not in the file header, so try xattrs */
1637 memset(page_virt, 0, PAGE_CACHE_SIZE);
1638 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
1640 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1641 "file header region or xattr region, inode %lu\n",
1642 ecryptfs_inode->i_ino);
1646 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1648 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1650 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1651 "file xattr region either, inode %lu\n",
1652 ecryptfs_inode->i_ino);
1655 if (crypt_stat->mount_crypt_stat->flags
1656 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1657 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1659 printk(KERN_WARNING "Attempt to access file with "
1660 "crypto metadata only in the extended attribute "
1661 "region, but eCryptfs was mounted without "
1662 "xattr support enabled. eCryptfs will not treat "
1663 "this like an encrypted file, inode %lu\n",
1664 ecryptfs_inode->i_ino);
1670 memset(page_virt, 0, PAGE_CACHE_SIZE);
1671 kmem_cache_free(ecryptfs_header_cache, page_virt);
1677 * ecryptfs_encrypt_filename - encrypt filename
1679 * CBC-encrypts the filename. We do not want to encrypt the same
1680 * filename with the same key and IV, which may happen with hard
1681 * links, so we prepend random bits to each filename.
1683 * Returns zero on success; non-zero otherwise
1686 ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1687 struct ecryptfs_crypt_stat *crypt_stat,
1688 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1692 filename->encrypted_filename = NULL;
1693 filename->encrypted_filename_size = 0;
1694 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
1695 || (mount_crypt_stat && (mount_crypt_stat->flags
1696 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
1698 size_t remaining_bytes;
1700 rc = ecryptfs_write_tag_70_packet(
1702 &filename->encrypted_filename_size,
1703 mount_crypt_stat, NULL,
1704 filename->filename_size);
1706 printk(KERN_ERR "%s: Error attempting to get packet "
1707 "size for tag 72; rc = [%d]\n", __func__,
1709 filename->encrypted_filename_size = 0;
1712 filename->encrypted_filename =
1713 kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1714 if (!filename->encrypted_filename) {
1715 printk(KERN_ERR "%s: Out of memory whilst attempting "
1716 "to kmalloc [%zd] bytes\n", __func__,
1717 filename->encrypted_filename_size);
1721 remaining_bytes = filename->encrypted_filename_size;
1722 rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
1727 filename->filename_size);
1729 printk(KERN_ERR "%s: Error attempting to generate "
1730 "tag 70 packet; rc = [%d]\n", __func__,
1732 kfree(filename->encrypted_filename);
1733 filename->encrypted_filename = NULL;
1734 filename->encrypted_filename_size = 0;
1737 filename->encrypted_filename_size = packet_size;
1739 printk(KERN_ERR "%s: No support for requested filename "
1740 "encryption method in this release\n", __func__);
1748 static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1749 const char *name, size_t name_size)
1753 (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
1754 if (!(*copied_name)) {
1758 memcpy((void *)(*copied_name), (void *)name, name_size);
1759 (*copied_name)[(name_size)] = '\0'; /* Only for convenience
1760 * in printing out the
1763 (*copied_name_size) = name_size;
1769 * ecryptfs_process_key_cipher - Perform key cipher initialization.
1770 * @key_tfm: Crypto context for key material, set by this function
1771 * @cipher_name: Name of the cipher
1772 * @key_size: Size of the key in bytes
1774 * Returns zero on success. Any crypto_tfm structs allocated here
1775 * should be released by other functions, such as on a superblock put
1776 * event, regardless of whether this function succeeds for fails.
1779 ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1780 char *cipher_name, size_t *key_size)
1782 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
1783 char *full_alg_name = NULL;
1787 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
1789 printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
1790 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
1793 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1797 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1798 if (IS_ERR(*key_tfm)) {
1799 rc = PTR_ERR(*key_tfm);
1800 printk(KERN_ERR "Unable to allocate crypto cipher with name "
1801 "[%s]; rc = [%d]\n", full_alg_name, rc);
1804 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1805 if (*key_size == 0) {
1806 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1808 *key_size = alg->max_keysize;
1810 get_random_bytes(dummy_key, *key_size);
1811 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
1813 printk(KERN_ERR "Error attempting to set key of size [%zd] for "
1814 "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name,
1820 kfree(full_alg_name);
1824 struct kmem_cache *ecryptfs_key_tfm_cache;
1825 static struct list_head key_tfm_list;
1826 struct mutex key_tfm_list_mutex;
1828 int __init ecryptfs_init_crypto(void)
1830 mutex_init(&key_tfm_list_mutex);
1831 INIT_LIST_HEAD(&key_tfm_list);
1836 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1838 * Called only at module unload time
1840 int ecryptfs_destroy_crypto(void)
1842 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1844 mutex_lock(&key_tfm_list_mutex);
1845 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1847 list_del(&key_tfm->key_tfm_list);
1848 if (key_tfm->key_tfm)
1849 crypto_free_blkcipher(key_tfm->key_tfm);
1850 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1852 mutex_unlock(&key_tfm_list_mutex);
1857 ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1860 struct ecryptfs_key_tfm *tmp_tfm;
1863 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1865 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1866 if (key_tfm != NULL)
1867 (*key_tfm) = tmp_tfm;
1870 printk(KERN_ERR "Error attempting to allocate from "
1871 "ecryptfs_key_tfm_cache\n");
1874 mutex_init(&tmp_tfm->key_tfm_mutex);
1875 strncpy(tmp_tfm->cipher_name, cipher_name,
1876 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
1877 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
1878 tmp_tfm->key_size = key_size;
1879 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1880 tmp_tfm->cipher_name,
1881 &tmp_tfm->key_size);
1883 printk(KERN_ERR "Error attempting to initialize key TFM "
1884 "cipher with name = [%s]; rc = [%d]\n",
1885 tmp_tfm->cipher_name, rc);
1886 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1887 if (key_tfm != NULL)
1891 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
1897 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1898 * @cipher_name: the name of the cipher to search for
1899 * @key_tfm: set to corresponding tfm if found
1901 * Searches for cached key_tfm matching @cipher_name
1902 * Must be called with &key_tfm_list_mutex held
1903 * Returns 1 if found, with @key_tfm set
1904 * Returns 0 if not found, with @key_tfm set to NULL
1906 int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1908 struct ecryptfs_key_tfm *tmp_key_tfm;
1910 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1912 list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1913 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1915 (*key_tfm) = tmp_key_tfm;
1925 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1927 * @tfm: set to cached tfm found, or new tfm created
1928 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1929 * @cipher_name: the name of the cipher to search for and/or add
1931 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1932 * Searches for cached item first, and creates new if not found.
1933 * Returns 0 on success, non-zero if adding new cipher failed
1935 int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1936 struct mutex **tfm_mutex,
1939 struct ecryptfs_key_tfm *key_tfm;
1943 (*tfm_mutex) = NULL;
1945 mutex_lock(&key_tfm_list_mutex);
1946 if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1947 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1949 printk(KERN_ERR "Error adding new key_tfm to list; "
1954 (*tfm) = key_tfm->key_tfm;
1955 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1957 mutex_unlock(&key_tfm_list_mutex);
1961 /* 64 characters forming a 6-bit target field */
1962 static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1965 "klmnopqrstuvwxyz");
1967 /* We could either offset on every reverse map or just pad some 0x00's
1968 * at the front here */
1969 static const unsigned char filename_rev_map[256] = {
1970 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1971 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1972 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1973 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1974 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1975 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1976 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1977 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1978 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1979 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1980 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1981 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1982 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1983 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1984 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
1985 0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */
1989 * ecryptfs_encode_for_filename
1990 * @dst: Destination location for encoded filename
1991 * @dst_size: Size of the encoded filename in bytes
1992 * @src: Source location for the filename to encode
1993 * @src_size: Size of the source in bytes
1995 static void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
1996 unsigned char *src, size_t src_size)
1999 size_t block_num = 0;
2000 size_t dst_offset = 0;
2001 unsigned char last_block[3];
2003 if (src_size == 0) {
2007 num_blocks = (src_size / 3);
2008 if ((src_size % 3) == 0) {
2009 memcpy(last_block, (&src[src_size - 3]), 3);
2012 last_block[2] = 0x00;
2013 switch (src_size % 3) {
2015 last_block[0] = src[src_size - 1];
2016 last_block[1] = 0x00;
2019 last_block[0] = src[src_size - 2];
2020 last_block[1] = src[src_size - 1];
2023 (*dst_size) = (num_blocks * 4);
2026 while (block_num < num_blocks) {
2027 unsigned char *src_block;
2028 unsigned char dst_block[4];
2030 if (block_num == (num_blocks - 1))
2031 src_block = last_block;
2033 src_block = &src[block_num * 3];
2034 dst_block[0] = ((src_block[0] >> 2) & 0x3F);
2035 dst_block[1] = (((src_block[0] << 4) & 0x30)
2036 | ((src_block[1] >> 4) & 0x0F));
2037 dst_block[2] = (((src_block[1] << 2) & 0x3C)
2038 | ((src_block[2] >> 6) & 0x03));
2039 dst_block[3] = (src_block[2] & 0x3F);
2040 dst[dst_offset++] = portable_filename_chars[dst_block[0]];
2041 dst[dst_offset++] = portable_filename_chars[dst_block[1]];
2042 dst[dst_offset++] = portable_filename_chars[dst_block[2]];
2043 dst[dst_offset++] = portable_filename_chars[dst_block[3]];
2050 static size_t ecryptfs_max_decoded_size(size_t encoded_size)
2052 /* Not exact; conservatively long. Every block of 4
2053 * encoded characters decodes into a block of 3
2054 * decoded characters. This segment of code provides
2055 * the caller with the maximum amount of allocated
2056 * space that @dst will need to point to in a
2057 * subsequent call. */
2058 return ((encoded_size + 1) * 3) / 4;
2062 * ecryptfs_decode_from_filename
2063 * @dst: If NULL, this function only sets @dst_size and returns. If
2064 * non-NULL, this function decodes the encoded octets in @src
2065 * into the memory that @dst points to.
2066 * @dst_size: Set to the size of the decoded string.
2067 * @src: The encoded set of octets to decode.
2068 * @src_size: The size of the encoded set of octets to decode.
2071 ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
2072 const unsigned char *src, size_t src_size)
2074 u8 current_bit_offset = 0;
2075 size_t src_byte_offset = 0;
2076 size_t dst_byte_offset = 0;
2079 (*dst_size) = ecryptfs_max_decoded_size(src_size);
2082 while (src_byte_offset < src_size) {
2083 unsigned char src_byte =
2084 filename_rev_map[(int)src[src_byte_offset]];
2086 switch (current_bit_offset) {
2088 dst[dst_byte_offset] = (src_byte << 2);
2089 current_bit_offset = 6;
2092 dst[dst_byte_offset++] |= (src_byte >> 4);
2093 dst[dst_byte_offset] = ((src_byte & 0xF)
2095 current_bit_offset = 4;
2098 dst[dst_byte_offset++] |= (src_byte >> 2);
2099 dst[dst_byte_offset] = (src_byte << 6);
2100 current_bit_offset = 2;
2103 dst[dst_byte_offset++] |= (src_byte);
2104 dst[dst_byte_offset] = 0;
2105 current_bit_offset = 0;
2110 (*dst_size) = dst_byte_offset;
2116 * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
2117 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
2118 * @name: The plaintext name
2119 * @length: The length of the plaintext
2120 * @encoded_name: The encypted name
2122 * Encrypts and encodes a filename into something that constitutes a
2123 * valid filename for a filesystem, with printable characters.
2125 * We assume that we have a properly initialized crypto context,
2126 * pointed to by crypt_stat->tfm.
2128 * Returns zero on success; non-zero on otherwise
2130 int ecryptfs_encrypt_and_encode_filename(
2131 char **encoded_name,
2132 size_t *encoded_name_size,
2133 struct ecryptfs_crypt_stat *crypt_stat,
2134 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2135 const char *name, size_t name_size)
2137 size_t encoded_name_no_prefix_size;
2140 (*encoded_name) = NULL;
2141 (*encoded_name_size) = 0;
2142 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
2143 || (mount_crypt_stat && (mount_crypt_stat->flags
2144 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) {
2145 struct ecryptfs_filename *filename;
2147 filename = kzalloc(sizeof(*filename), GFP_KERNEL);
2149 printk(KERN_ERR "%s: Out of memory whilst attempting "
2150 "to kzalloc [%zd] bytes\n", __func__,
2155 filename->filename = (char *)name;
2156 filename->filename_size = name_size;
2157 rc = ecryptfs_encrypt_filename(filename, crypt_stat,
2160 printk(KERN_ERR "%s: Error attempting to encrypt "
2161 "filename; rc = [%d]\n", __func__, rc);
2165 ecryptfs_encode_for_filename(
2166 NULL, &encoded_name_no_prefix_size,
2167 filename->encrypted_filename,
2168 filename->encrypted_filename_size);
2169 if ((crypt_stat && (crypt_stat->flags
2170 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2171 || (mount_crypt_stat
2172 && (mount_crypt_stat->flags
2173 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)))
2174 (*encoded_name_size) =
2175 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2176 + encoded_name_no_prefix_size);
2178 (*encoded_name_size) =
2179 (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2180 + encoded_name_no_prefix_size);
2181 (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
2182 if (!(*encoded_name)) {
2183 printk(KERN_ERR "%s: Out of memory whilst attempting "
2184 "to kzalloc [%zd] bytes\n", __func__,
2185 (*encoded_name_size));
2187 kfree(filename->encrypted_filename);
2191 if ((crypt_stat && (crypt_stat->flags
2192 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2193 || (mount_crypt_stat
2194 && (mount_crypt_stat->flags
2195 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
2196 memcpy((*encoded_name),
2197 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2198 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
2199 ecryptfs_encode_for_filename(
2201 + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
2202 &encoded_name_no_prefix_size,
2203 filename->encrypted_filename,
2204 filename->encrypted_filename_size);
2205 (*encoded_name_size) =
2206 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2207 + encoded_name_no_prefix_size);
2208 (*encoded_name)[(*encoded_name_size)] = '\0';
2213 printk(KERN_ERR "%s: Error attempting to encode "
2214 "encrypted filename; rc = [%d]\n", __func__,
2216 kfree((*encoded_name));
2217 (*encoded_name) = NULL;
2218 (*encoded_name_size) = 0;
2220 kfree(filename->encrypted_filename);
2223 rc = ecryptfs_copy_filename(encoded_name,
2232 * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
2233 * @plaintext_name: The plaintext name
2234 * @plaintext_name_size: The plaintext name size
2235 * @ecryptfs_dir_dentry: eCryptfs directory dentry
2236 * @name: The filename in cipher text
2237 * @name_size: The cipher text name size
2239 * Decrypts and decodes the filename.
2241 * Returns zero on error; non-zero otherwise
2243 int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
2244 size_t *plaintext_name_size,
2245 struct dentry *ecryptfs_dir_dentry,
2246 const char *name, size_t name_size)
2248 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2249 &ecryptfs_superblock_to_private(
2250 ecryptfs_dir_dentry->d_sb)->mount_crypt_stat;
2252 size_t decoded_name_size;
2256 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
2257 && !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
2258 && (name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
2259 && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2260 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
2261 const char *orig_name = name;
2262 size_t orig_name_size = name_size;
2264 name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2265 name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2266 ecryptfs_decode_from_filename(NULL, &decoded_name_size,
2268 decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
2269 if (!decoded_name) {
2270 printk(KERN_ERR "%s: Out of memory whilst attempting "
2271 "to kmalloc [%zd] bytes\n", __func__,
2276 ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
2278 rc = ecryptfs_parse_tag_70_packet(plaintext_name,
2279 plaintext_name_size,
2285 printk(KERN_INFO "%s: Could not parse tag 70 packet "
2286 "from filename; copying through filename "
2287 "as-is\n", __func__);
2288 rc = ecryptfs_copy_filename(plaintext_name,
2289 plaintext_name_size,
2290 orig_name, orig_name_size);
2294 rc = ecryptfs_copy_filename(plaintext_name,
2295 plaintext_name_size,
2300 kfree(decoded_name);
2305 #define ENC_NAME_MAX_BLOCKLEN_8_OR_16 143
2307 int ecryptfs_set_f_namelen(long *namelen, long lower_namelen,
2308 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
2310 struct blkcipher_desc desc;
2311 struct mutex *tfm_mutex;
2312 size_t cipher_blocksize;
2315 if (!(mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
2316 (*namelen) = lower_namelen;
2320 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
2321 mount_crypt_stat->global_default_fn_cipher_name);
2327 mutex_lock(tfm_mutex);
2328 cipher_blocksize = crypto_blkcipher_blocksize(desc.tfm);
2329 mutex_unlock(tfm_mutex);
2331 /* Return an exact amount for the common cases */
2332 if (lower_namelen == NAME_MAX
2333 && (cipher_blocksize == 8 || cipher_blocksize == 16)) {
2334 (*namelen) = ENC_NAME_MAX_BLOCKLEN_8_OR_16;
2338 /* Return a safe estimate for the uncommon cases */
2339 (*namelen) = lower_namelen;
2340 (*namelen) -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2341 /* Since this is the max decoded size, subtract 1 "decoded block" len */
2342 (*namelen) = ecryptfs_max_decoded_size(*namelen) - 3;
2343 (*namelen) -= ECRYPTFS_TAG_70_MAX_METADATA_SIZE;
2344 (*namelen) -= ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES;
2345 /* Worst case is that the filename is padded nearly a full block size */
2346 (*namelen) -= cipher_blocksize - 1;