2 * eCryptfs: Linux filesystem encryption layer
4 * Copyright (C) 1997-2004 Erez Zadok
5 * Copyright (C) 2001-2004 Stony Brook University
6 * Copyright (C) 2004-2007 International Business Machines Corp.
7 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
8 * Michael C. Thompson <mcthomps@us.ibm.com>
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of the
13 * License, or (at your option) any later version.
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
27 #include <linux/mount.h>
28 #include <linux/pagemap.h>
29 #include <linux/random.h>
30 #include <linux/compiler.h>
31 #include <linux/key.h>
32 #include <linux/namei.h>
33 #include <linux/crypto.h>
34 #include <linux/file.h>
35 #include <linux/scatterlist.h>
36 #include <asm/unaligned.h>
37 #include "ecryptfs_kernel.h"
40 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
41 struct page *dst_page, int dst_offset,
42 struct page *src_page, int src_offset, int size,
45 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
46 struct page *dst_page, int dst_offset,
47 struct page *src_page, int src_offset, int size,
52 * @dst: Buffer to take hex character representation of contents of
53 * src; must be at least of size (src_size * 2)
54 * @src: Buffer to be converted to a hex string respresentation
55 * @src_size: number of bytes to convert
57 void ecryptfs_to_hex(char *dst, char *src, size_t src_size)
61 for (x = 0; x < src_size; x++)
62 sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]);
67 * @dst: Buffer to take the bytes from src hex; must be at least of
69 * @src: Buffer to be converted from a hex string respresentation to raw value
70 * @dst_size: size of dst buffer, or number of hex characters pairs to convert
72 void ecryptfs_from_hex(char *dst, char *src, int dst_size)
77 for (x = 0; x < dst_size; x++) {
79 tmp[1] = src[x * 2 + 1];
80 dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
85 * ecryptfs_calculate_md5 - calculates the md5 of @src
86 * @dst: Pointer to 16 bytes of allocated memory
87 * @crypt_stat: Pointer to crypt_stat struct for the current inode
88 * @src: Data to be md5'd
89 * @len: Length of @src
91 * Uses the allocated crypto context that crypt_stat references to
92 * generate the MD5 sum of the contents of src.
94 static int ecryptfs_calculate_md5(char *dst,
95 struct ecryptfs_crypt_stat *crypt_stat,
98 struct scatterlist sg;
99 struct hash_desc desc = {
100 .tfm = crypt_stat->hash_tfm,
101 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
105 mutex_lock(&crypt_stat->cs_hash_tfm_mutex);
106 sg_init_one(&sg, (u8 *)src, len);
108 desc.tfm = crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH, 0,
110 if (IS_ERR(desc.tfm)) {
111 rc = PTR_ERR(desc.tfm);
112 ecryptfs_printk(KERN_ERR, "Error attempting to "
113 "allocate crypto context; rc = [%d]\n",
117 crypt_stat->hash_tfm = desc.tfm;
119 rc = crypto_hash_init(&desc);
122 "%s: Error initializing crypto hash; rc = [%d]\n",
126 rc = crypto_hash_update(&desc, &sg, len);
129 "%s: Error updating crypto hash; rc = [%d]\n",
133 rc = crypto_hash_final(&desc, dst);
136 "%s: Error finalizing crypto hash; rc = [%d]\n",
141 mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
145 static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
147 char *chaining_modifier)
149 int cipher_name_len = strlen(cipher_name);
150 int chaining_modifier_len = strlen(chaining_modifier);
151 int algified_name_len;
154 algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
155 (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
156 if (!(*algified_name)) {
160 snprintf((*algified_name), algified_name_len, "%s(%s)",
161 chaining_modifier, cipher_name);
169 * @iv: destination for the derived iv vale
170 * @crypt_stat: Pointer to crypt_stat struct for the current inode
171 * @offset: Offset of the extent whose IV we are to derive
173 * Generate the initialization vector from the given root IV and page
176 * Returns zero on success; non-zero on error.
178 int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
182 char dst[MD5_DIGEST_SIZE];
183 char src[ECRYPTFS_MAX_IV_BYTES + 16];
185 if (unlikely(ecryptfs_verbosity > 0)) {
186 ecryptfs_printk(KERN_DEBUG, "root iv:\n");
187 ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
189 /* TODO: It is probably secure to just cast the least
190 * significant bits of the root IV into an unsigned long and
191 * add the offset to that rather than go through all this
192 * hashing business. -Halcrow */
193 memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
194 memset((src + crypt_stat->iv_bytes), 0, 16);
195 snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
196 if (unlikely(ecryptfs_verbosity > 0)) {
197 ecryptfs_printk(KERN_DEBUG, "source:\n");
198 ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
200 rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
201 (crypt_stat->iv_bytes + 16));
203 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
204 "MD5 while generating IV for a page\n");
207 memcpy(iv, dst, crypt_stat->iv_bytes);
208 if (unlikely(ecryptfs_verbosity > 0)) {
209 ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
210 ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
217 * ecryptfs_init_crypt_stat
218 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
220 * Initialize the crypt_stat structure.
223 ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
225 memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
226 INIT_LIST_HEAD(&crypt_stat->keysig_list);
227 mutex_init(&crypt_stat->keysig_list_mutex);
228 mutex_init(&crypt_stat->cs_mutex);
229 mutex_init(&crypt_stat->cs_tfm_mutex);
230 mutex_init(&crypt_stat->cs_hash_tfm_mutex);
231 crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
235 * ecryptfs_destroy_crypt_stat
236 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
238 * Releases all memory associated with a crypt_stat struct.
240 void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
242 struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
245 crypto_free_blkcipher(crypt_stat->tfm);
246 if (crypt_stat->hash_tfm)
247 crypto_free_hash(crypt_stat->hash_tfm);
248 list_for_each_entry_safe(key_sig, key_sig_tmp,
249 &crypt_stat->keysig_list, crypt_stat_list) {
250 list_del(&key_sig->crypt_stat_list);
251 kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
253 memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
256 void ecryptfs_destroy_mount_crypt_stat(
257 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
259 struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
261 if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
263 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
264 list_for_each_entry_safe(auth_tok, auth_tok_tmp,
265 &mount_crypt_stat->global_auth_tok_list,
266 mount_crypt_stat_list) {
267 list_del(&auth_tok->mount_crypt_stat_list);
268 mount_crypt_stat->num_global_auth_toks--;
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);
305 sg_set_page(&sg[i], pg, 0, offset);
306 remainder_of_page = PAGE_CACHE_SIZE - offset;
307 if (size >= remainder_of_page) {
309 sg[i].length = remainder_of_page;
310 addr += remainder_of_page;
311 size -= remainder_of_page;
326 * encrypt_scatterlist
327 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
328 * @dest_sg: Destination of encrypted data
329 * @src_sg: Data to be encrypted
330 * @size: Length of data to be encrypted
331 * @iv: iv to use during encryption
333 * Returns the number of bytes encrypted; negative value on error
335 static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
336 struct scatterlist *dest_sg,
337 struct scatterlist *src_sg, int size,
340 struct blkcipher_desc desc = {
341 .tfm = crypt_stat->tfm,
343 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
347 BUG_ON(!crypt_stat || !crypt_stat->tfm
348 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
349 if (unlikely(ecryptfs_verbosity > 0)) {
350 ecryptfs_printk(KERN_DEBUG, "Key size [%d]; key:\n",
351 crypt_stat->key_size);
352 ecryptfs_dump_hex(crypt_stat->key,
353 crypt_stat->key_size);
355 /* Consider doing this once, when the file is opened */
356 mutex_lock(&crypt_stat->cs_tfm_mutex);
357 if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
358 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
359 crypt_stat->key_size);
360 crypt_stat->flags |= ECRYPTFS_KEY_SET;
363 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
365 mutex_unlock(&crypt_stat->cs_tfm_mutex);
369 ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size);
370 crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size);
371 mutex_unlock(&crypt_stat->cs_tfm_mutex);
377 * ecryptfs_lower_offset_for_extent
379 * Convert an eCryptfs page index into a lower byte offset
381 static void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
382 struct ecryptfs_crypt_stat *crypt_stat)
384 (*offset) = (crypt_stat->num_header_bytes_at_front
385 + (crypt_stat->extent_size * extent_num));
389 * ecryptfs_encrypt_extent
390 * @enc_extent_page: Allocated page into which to encrypt the data in
392 * @crypt_stat: crypt_stat containing cryptographic context for the
393 * encryption operation
394 * @page: Page containing plaintext data extent to encrypt
395 * @extent_offset: Page extent offset for use in generating IV
397 * Encrypts one extent of data.
399 * Return zero on success; non-zero otherwise
401 static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
402 struct ecryptfs_crypt_stat *crypt_stat,
404 unsigned long extent_offset)
407 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
410 extent_base = (((loff_t)page->index)
411 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
412 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
413 (extent_base + extent_offset));
415 ecryptfs_printk(KERN_ERR, "Error attempting to "
416 "derive IV for extent [0x%.16x]; "
417 "rc = [%d]\n", (extent_base + extent_offset),
421 if (unlikely(ecryptfs_verbosity > 0)) {
422 ecryptfs_printk(KERN_DEBUG, "Encrypting extent "
424 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
425 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
427 ecryptfs_dump_hex((char *)
429 + (extent_offset * crypt_stat->extent_size)),
432 rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0,
434 * crypt_stat->extent_size),
435 crypt_stat->extent_size, extent_iv);
437 printk(KERN_ERR "%s: Error attempting to encrypt page with "
438 "page->index = [%ld], extent_offset = [%ld]; "
439 "rc = [%d]\n", __func__, page->index, extent_offset,
444 if (unlikely(ecryptfs_verbosity > 0)) {
445 ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; "
446 "rc = [%d]\n", (extent_base + extent_offset),
448 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
450 ecryptfs_dump_hex((char *)(page_address(enc_extent_page)), 8);
457 * ecryptfs_encrypt_page
458 * @page: Page mapped from the eCryptfs inode for the file; contains
459 * decrypted content that needs to be encrypted (to a temporary
460 * page; not in place) and written out to the lower file
462 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
463 * that eCryptfs pages may straddle the lower pages -- for instance,
464 * if the file was created on a machine with an 8K page size
465 * (resulting in an 8K header), and then the file is copied onto a
466 * host with a 32K page size, then when reading page 0 of the eCryptfs
467 * file, 24K of page 0 of the lower file will be read and decrypted,
468 * and then 8K of page 1 of the lower file will be read and decrypted.
470 * Returns zero on success; negative on error
472 int ecryptfs_encrypt_page(struct page *page)
474 struct inode *ecryptfs_inode;
475 struct ecryptfs_crypt_stat *crypt_stat;
476 char *enc_extent_virt;
477 struct page *enc_extent_page = NULL;
478 loff_t extent_offset;
481 ecryptfs_inode = page->mapping->host;
483 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
484 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
485 enc_extent_page = alloc_page(GFP_USER);
486 if (!enc_extent_page) {
488 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
489 "encrypted extent\n");
492 enc_extent_virt = kmap(enc_extent_page);
493 for (extent_offset = 0;
494 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
498 rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
501 printk(KERN_ERR "%s: Error encrypting extent; "
502 "rc = [%d]\n", __func__, rc);
505 ecryptfs_lower_offset_for_extent(
506 &offset, ((((loff_t)page->index)
508 / crypt_stat->extent_size))
509 + extent_offset), crypt_stat);
510 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt,
511 offset, crypt_stat->extent_size);
513 ecryptfs_printk(KERN_ERR, "Error attempting "
514 "to write lower page; rc = [%d]"
520 if (enc_extent_page) {
521 kunmap(enc_extent_page);
522 __free_page(enc_extent_page);
527 static int ecryptfs_decrypt_extent(struct page *page,
528 struct ecryptfs_crypt_stat *crypt_stat,
529 struct page *enc_extent_page,
530 unsigned long extent_offset)
533 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
536 extent_base = (((loff_t)page->index)
537 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
538 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
539 (extent_base + extent_offset));
541 ecryptfs_printk(KERN_ERR, "Error attempting to "
542 "derive IV for extent [0x%.16x]; "
543 "rc = [%d]\n", (extent_base + extent_offset),
547 if (unlikely(ecryptfs_verbosity > 0)) {
548 ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
550 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
551 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
553 ecryptfs_dump_hex((char *)
554 (page_address(enc_extent_page)
555 + (extent_offset * crypt_stat->extent_size)),
558 rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
560 * crypt_stat->extent_size),
562 crypt_stat->extent_size, extent_iv);
564 printk(KERN_ERR "%s: Error attempting to decrypt to page with "
565 "page->index = [%ld], extent_offset = [%ld]; "
566 "rc = [%d]\n", __func__, page->index, extent_offset,
571 if (unlikely(ecryptfs_verbosity > 0)) {
572 ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16x]; "
573 "rc = [%d]\n", (extent_base + extent_offset),
575 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
577 ecryptfs_dump_hex((char *)(page_address(page)
579 * crypt_stat->extent_size)), 8);
586 * ecryptfs_decrypt_page
587 * @page: Page mapped from the eCryptfs inode for the file; data read
588 * and decrypted from the lower file will be written into this
591 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
592 * that eCryptfs pages may straddle the lower pages -- for instance,
593 * if the file was created on a machine with an 8K page size
594 * (resulting in an 8K header), and then the file is copied onto a
595 * host with a 32K page size, then when reading page 0 of the eCryptfs
596 * file, 24K of page 0 of the lower file will be read and decrypted,
597 * and then 8K of page 1 of the lower file will be read and decrypted.
599 * Returns zero on success; negative on error
601 int ecryptfs_decrypt_page(struct page *page)
603 struct inode *ecryptfs_inode;
604 struct ecryptfs_crypt_stat *crypt_stat;
605 char *enc_extent_virt;
606 struct page *enc_extent_page = NULL;
607 unsigned long extent_offset;
610 ecryptfs_inode = page->mapping->host;
612 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
613 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
614 enc_extent_page = alloc_page(GFP_USER);
615 if (!enc_extent_page) {
617 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
618 "encrypted extent\n");
621 enc_extent_virt = kmap(enc_extent_page);
622 for (extent_offset = 0;
623 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
627 ecryptfs_lower_offset_for_extent(
628 &offset, ((page->index * (PAGE_CACHE_SIZE
629 / crypt_stat->extent_size))
630 + extent_offset), crypt_stat);
631 rc = ecryptfs_read_lower(enc_extent_virt, offset,
632 crypt_stat->extent_size,
635 ecryptfs_printk(KERN_ERR, "Error attempting "
636 "to read lower page; rc = [%d]"
640 rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
643 printk(KERN_ERR "%s: Error encrypting extent; "
644 "rc = [%d]\n", __func__, rc);
649 if (enc_extent_page) {
650 kunmap(enc_extent_page);
651 __free_page(enc_extent_page);
657 * decrypt_scatterlist
658 * @crypt_stat: Cryptographic context
659 * @dest_sg: The destination scatterlist to decrypt into
660 * @src_sg: The source scatterlist to decrypt from
661 * @size: The number of bytes to decrypt
662 * @iv: The initialization vector to use for the decryption
664 * Returns the number of bytes decrypted; negative value on error
666 static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
667 struct scatterlist *dest_sg,
668 struct scatterlist *src_sg, int size,
671 struct blkcipher_desc desc = {
672 .tfm = crypt_stat->tfm,
674 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
678 /* Consider doing this once, when the file is opened */
679 mutex_lock(&crypt_stat->cs_tfm_mutex);
680 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
681 crypt_stat->key_size);
683 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
685 mutex_unlock(&crypt_stat->cs_tfm_mutex);
689 ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
690 rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size);
691 mutex_unlock(&crypt_stat->cs_tfm_mutex);
693 ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n",
703 * ecryptfs_encrypt_page_offset
704 * @crypt_stat: The cryptographic context
705 * @dst_page: The page to encrypt into
706 * @dst_offset: The offset in the page to encrypt into
707 * @src_page: The page to encrypt from
708 * @src_offset: The offset in the page to encrypt from
709 * @size: The number of bytes to encrypt
710 * @iv: The initialization vector to use for the encryption
712 * Returns the number of bytes encrypted
715 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
716 struct page *dst_page, int dst_offset,
717 struct page *src_page, int src_offset, int size,
720 struct scatterlist src_sg, dst_sg;
722 sg_init_table(&src_sg, 1);
723 sg_init_table(&dst_sg, 1);
725 sg_set_page(&src_sg, src_page, size, src_offset);
726 sg_set_page(&dst_sg, dst_page, size, dst_offset);
727 return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
731 * ecryptfs_decrypt_page_offset
732 * @crypt_stat: The cryptographic context
733 * @dst_page: The page to decrypt into
734 * @dst_offset: The offset in the page to decrypt into
735 * @src_page: The page to decrypt from
736 * @src_offset: The offset in the page to decrypt from
737 * @size: The number of bytes to decrypt
738 * @iv: The initialization vector to use for the decryption
740 * Returns the number of bytes decrypted
743 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
744 struct page *dst_page, int dst_offset,
745 struct page *src_page, int src_offset, int size,
748 struct scatterlist src_sg, dst_sg;
750 sg_init_table(&src_sg, 1);
751 sg_set_page(&src_sg, src_page, size, src_offset);
753 sg_init_table(&dst_sg, 1);
754 sg_set_page(&dst_sg, dst_page, size, dst_offset);
756 return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
759 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
762 * ecryptfs_init_crypt_ctx
763 * @crypt_stat: Uninitilized crypt stats structure
765 * Initialize the crypto context.
767 * TODO: Performance: Keep a cache of initialized cipher contexts;
768 * only init if needed
770 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
775 if (!crypt_stat->cipher) {
776 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
779 ecryptfs_printk(KERN_DEBUG,
780 "Initializing cipher [%s]; strlen = [%d]; "
781 "key_size_bits = [%d]\n",
782 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
783 crypt_stat->key_size << 3);
784 if (crypt_stat->tfm) {
788 mutex_lock(&crypt_stat->cs_tfm_mutex);
789 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
790 crypt_stat->cipher, "cbc");
793 crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
795 kfree(full_alg_name);
796 if (IS_ERR(crypt_stat->tfm)) {
797 rc = PTR_ERR(crypt_stat->tfm);
798 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
799 "Error initializing cipher [%s]\n",
803 crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
806 mutex_unlock(&crypt_stat->cs_tfm_mutex);
811 static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
815 crypt_stat->extent_mask = 0xFFFFFFFF;
816 crypt_stat->extent_shift = 0;
817 if (crypt_stat->extent_size == 0)
819 extent_size_tmp = crypt_stat->extent_size;
820 while ((extent_size_tmp & 0x01) == 0) {
821 extent_size_tmp >>= 1;
822 crypt_stat->extent_mask <<= 1;
823 crypt_stat->extent_shift++;
827 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
829 /* Default values; may be overwritten as we are parsing the
831 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
832 set_extent_mask_and_shift(crypt_stat);
833 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
834 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
835 crypt_stat->num_header_bytes_at_front = 0;
837 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
838 crypt_stat->num_header_bytes_at_front =
839 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
841 crypt_stat->num_header_bytes_at_front = PAGE_CACHE_SIZE;
846 * ecryptfs_compute_root_iv
849 * On error, sets the root IV to all 0's.
851 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
854 char dst[MD5_DIGEST_SIZE];
856 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
857 BUG_ON(crypt_stat->iv_bytes <= 0);
858 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
860 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
861 "cannot generate root IV\n");
864 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
865 crypt_stat->key_size);
867 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
868 "MD5 while generating root IV\n");
871 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
874 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
875 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
880 static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
882 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
883 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
884 ecryptfs_compute_root_iv(crypt_stat);
885 if (unlikely(ecryptfs_verbosity > 0)) {
886 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
887 ecryptfs_dump_hex(crypt_stat->key,
888 crypt_stat->key_size);
893 * ecryptfs_copy_mount_wide_flags_to_inode_flags
894 * @crypt_stat: The inode's cryptographic context
895 * @mount_crypt_stat: The mount point's cryptographic context
897 * This function propagates the mount-wide flags to individual inode
900 static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
901 struct ecryptfs_crypt_stat *crypt_stat,
902 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
904 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
905 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
906 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
907 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
908 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
909 crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
910 if (mount_crypt_stat->flags
911 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
912 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
913 else if (mount_crypt_stat->flags
914 & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
915 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
919 static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
920 struct ecryptfs_crypt_stat *crypt_stat,
921 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
923 struct ecryptfs_global_auth_tok *global_auth_tok;
926 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
927 list_for_each_entry(global_auth_tok,
928 &mount_crypt_stat->global_auth_tok_list,
929 mount_crypt_stat_list) {
930 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
932 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
934 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
936 &mount_crypt_stat->global_auth_tok_list_mutex);
940 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
946 * ecryptfs_set_default_crypt_stat_vals
947 * @crypt_stat: The inode's cryptographic context
948 * @mount_crypt_stat: The mount point's cryptographic context
950 * Default values in the event that policy does not override them.
952 static void ecryptfs_set_default_crypt_stat_vals(
953 struct ecryptfs_crypt_stat *crypt_stat,
954 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
956 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
958 ecryptfs_set_default_sizes(crypt_stat);
959 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
960 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
961 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
962 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
963 crypt_stat->mount_crypt_stat = mount_crypt_stat;
967 * ecryptfs_new_file_context
968 * @ecryptfs_dentry: The eCryptfs dentry
970 * If the crypto context for the file has not yet been established,
971 * this is where we do that. Establishing a new crypto context
972 * involves the following decisions:
973 * - What cipher to use?
974 * - What set of authentication tokens to use?
975 * Here we just worry about getting enough information into the
976 * authentication tokens so that we know that they are available.
977 * We associate the available authentication tokens with the new file
978 * via the set of signatures in the crypt_stat struct. Later, when
979 * the headers are actually written out, we may again defer to
980 * userspace to perform the encryption of the session key; for the
981 * foreseeable future, this will be the case with public key packets.
983 * Returns zero on success; non-zero otherwise
985 int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
987 struct ecryptfs_crypt_stat *crypt_stat =
988 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
989 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
990 &ecryptfs_superblock_to_private(
991 ecryptfs_dentry->d_sb)->mount_crypt_stat;
995 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
996 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
997 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
999 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
1002 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
1003 "to the inode key sigs; rc = [%d]\n", rc);
1007 strlen(mount_crypt_stat->global_default_cipher_name);
1008 memcpy(crypt_stat->cipher,
1009 mount_crypt_stat->global_default_cipher_name,
1011 crypt_stat->cipher[cipher_name_len] = '\0';
1012 crypt_stat->key_size =
1013 mount_crypt_stat->global_default_cipher_key_size;
1014 ecryptfs_generate_new_key(crypt_stat);
1015 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1017 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
1018 "context for cipher [%s]: rc = [%d]\n",
1019 crypt_stat->cipher, rc);
1025 * contains_ecryptfs_marker - check for the ecryptfs marker
1026 * @data: The data block in which to check
1028 * Returns one if marker found; zero if not found
1030 static int contains_ecryptfs_marker(char *data)
1034 m_1 = get_unaligned_be32(data);
1035 m_2 = get_unaligned_be32(data + 4);
1036 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
1038 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1039 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1040 MAGIC_ECRYPTFS_MARKER);
1041 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1042 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1046 struct ecryptfs_flag_map_elem {
1051 /* Add support for additional flags by adding elements here. */
1052 static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1053 {0x00000001, ECRYPTFS_ENABLE_HMAC},
1054 {0x00000002, ECRYPTFS_ENCRYPTED},
1055 {0x00000004, ECRYPTFS_METADATA_IN_XATTR},
1056 {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
1060 * ecryptfs_process_flags
1061 * @crypt_stat: The cryptographic context
1062 * @page_virt: Source data to be parsed
1063 * @bytes_read: Updated with the number of bytes read
1065 * Returns zero on success; non-zero if the flag set is invalid
1067 static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1068 char *page_virt, int *bytes_read)
1074 flags = get_unaligned_be32(page_virt);
1075 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1076 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1077 if (flags & ecryptfs_flag_map[i].file_flag) {
1078 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
1080 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
1081 /* Version is in top 8 bits of the 32-bit flag vector */
1082 crypt_stat->file_version = ((flags >> 24) & 0xFF);
1088 * write_ecryptfs_marker
1089 * @page_virt: The pointer to in a page to begin writing the marker
1090 * @written: Number of bytes written
1092 * Marker = 0x3c81b7f5
1094 static void write_ecryptfs_marker(char *page_virt, size_t *written)
1098 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1099 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
1100 put_unaligned_be32(m_1, page_virt);
1101 page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
1102 put_unaligned_be32(m_2, page_virt);
1103 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1107 write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat,
1113 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1114 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1115 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
1116 flags |= ecryptfs_flag_map[i].file_flag;
1117 /* Version is in top 8 bits of the 32-bit flag vector */
1118 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
1119 put_unaligned_be32(flags, page_virt);
1123 struct ecryptfs_cipher_code_str_map_elem {
1124 char cipher_str[16];
1128 /* Add support for additional ciphers by adding elements here. The
1129 * cipher_code is whatever OpenPGP applicatoins use to identify the
1130 * ciphers. List in order of probability. */
1131 static struct ecryptfs_cipher_code_str_map_elem
1132 ecryptfs_cipher_code_str_map[] = {
1133 {"aes",RFC2440_CIPHER_AES_128 },
1134 {"blowfish", RFC2440_CIPHER_BLOWFISH},
1135 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1136 {"cast5", RFC2440_CIPHER_CAST_5},
1137 {"twofish", RFC2440_CIPHER_TWOFISH},
1138 {"cast6", RFC2440_CIPHER_CAST_6},
1139 {"aes", RFC2440_CIPHER_AES_192},
1140 {"aes", RFC2440_CIPHER_AES_256}
1144 * ecryptfs_code_for_cipher_string
1145 * @cipher_name: The string alias for the cipher
1146 * @key_bytes: Length of key in bytes; used for AES code selection
1148 * Returns zero on no match, or the cipher code on match
1150 u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
1154 struct ecryptfs_cipher_code_str_map_elem *map =
1155 ecryptfs_cipher_code_str_map;
1157 if (strcmp(cipher_name, "aes") == 0) {
1158 switch (key_bytes) {
1160 code = RFC2440_CIPHER_AES_128;
1163 code = RFC2440_CIPHER_AES_192;
1166 code = RFC2440_CIPHER_AES_256;
1169 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1170 if (strcmp(cipher_name, map[i].cipher_str) == 0) {
1171 code = map[i].cipher_code;
1179 * ecryptfs_cipher_code_to_string
1180 * @str: Destination to write out the cipher name
1181 * @cipher_code: The code to convert to cipher name string
1183 * Returns zero on success
1185 int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
1191 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1192 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1193 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1194 if (str[0] == '\0') {
1195 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1196 "[%d]\n", cipher_code);
1202 int ecryptfs_read_and_validate_header_region(char *data,
1203 struct inode *ecryptfs_inode)
1205 struct ecryptfs_crypt_stat *crypt_stat =
1206 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
1209 if (crypt_stat->extent_size == 0)
1210 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
1211 rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
1214 printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
1218 if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) {
1226 ecryptfs_write_header_metadata(char *virt,
1227 struct ecryptfs_crypt_stat *crypt_stat,
1230 u32 header_extent_size;
1231 u16 num_header_extents_at_front;
1233 header_extent_size = (u32)crypt_stat->extent_size;
1234 num_header_extents_at_front =
1235 (u16)(crypt_stat->num_header_bytes_at_front
1236 / crypt_stat->extent_size);
1237 put_unaligned_be32(header_extent_size, virt);
1239 put_unaligned_be16(num_header_extents_at_front, virt);
1243 struct kmem_cache *ecryptfs_header_cache_1;
1244 struct kmem_cache *ecryptfs_header_cache_2;
1247 * ecryptfs_write_headers_virt
1248 * @page_virt: The virtual address to write the headers to
1249 * @max: The size of memory allocated at page_virt
1250 * @size: Set to the number of bytes written by this function
1251 * @crypt_stat: The cryptographic context
1252 * @ecryptfs_dentry: The eCryptfs dentry
1257 * Octets 0-7: Unencrypted file size (big-endian)
1258 * Octets 8-15: eCryptfs special marker
1259 * Octets 16-19: Flags
1260 * Octet 16: File format version number (between 0 and 255)
1261 * Octets 17-18: Reserved
1262 * Octet 19: Bit 1 (lsb): Reserved
1264 * Bits 3-8: Reserved
1265 * Octets 20-23: Header extent size (big-endian)
1266 * Octets 24-25: Number of header extents at front of file
1268 * Octet 26: Begin RFC 2440 authentication token packet set
1270 * Lower data (CBC encrypted)
1272 * Lower data (CBC encrypted)
1275 * Returns zero on success
1277 static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1279 struct ecryptfs_crypt_stat *crypt_stat,
1280 struct dentry *ecryptfs_dentry)
1286 offset = ECRYPTFS_FILE_SIZE_BYTES;
1287 write_ecryptfs_marker((page_virt + offset), &written);
1289 write_ecryptfs_flags((page_virt + offset), crypt_stat, &written);
1291 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1294 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1295 ecryptfs_dentry, &written,
1298 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1299 "set; rc = [%d]\n", rc);
1308 ecryptfs_write_metadata_to_contents(struct dentry *ecryptfs_dentry,
1309 char *virt, size_t virt_len)
1313 rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, virt,
1316 printk(KERN_ERR "%s: Error attempting to write header "
1317 "information to lower file; rc = [%d]\n", __func__,
1323 ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1324 char *page_virt, size_t size)
1328 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1333 static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1338 page = alloc_pages(gfp_mask | __GFP_ZERO, order);
1340 return (unsigned long) page_address(page);
1345 * ecryptfs_write_metadata
1346 * @ecryptfs_dentry: The eCryptfs dentry
1348 * Write the file headers out. This will likely involve a userspace
1349 * callout, in which the session key is encrypted with one or more
1350 * public keys and/or the passphrase necessary to do the encryption is
1351 * retrieved via a prompt. Exactly what happens at this point should
1352 * be policy-dependent.
1354 * Returns zero on success; non-zero on error
1356 int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
1358 struct ecryptfs_crypt_stat *crypt_stat =
1359 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
1366 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1367 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
1368 printk(KERN_ERR "Key is invalid; bailing out\n");
1373 printk(KERN_WARNING "%s: Encrypted flag not set\n",
1378 virt_len = crypt_stat->num_header_bytes_at_front;
1379 order = get_order(virt_len);
1380 /* Released in this function */
1381 virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
1383 printk(KERN_ERR "%s: Out of memory\n", __func__);
1387 rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
1390 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
1394 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1395 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt,
1398 rc = ecryptfs_write_metadata_to_contents(ecryptfs_dentry, virt,
1401 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
1402 "rc = [%d]\n", __func__, rc);
1406 free_pages((unsigned long)virt, order);
1411 #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1412 #define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1413 static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
1414 char *virt, int *bytes_read,
1415 int validate_header_size)
1418 u32 header_extent_size;
1419 u16 num_header_extents_at_front;
1421 header_extent_size = get_unaligned_be32(virt);
1422 virt += sizeof(__be32);
1423 num_header_extents_at_front = get_unaligned_be16(virt);
1424 crypt_stat->num_header_bytes_at_front =
1425 (((size_t)num_header_extents_at_front
1426 * (size_t)header_extent_size));
1427 (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
1428 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
1429 && (crypt_stat->num_header_bytes_at_front
1430 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
1432 printk(KERN_WARNING "Invalid header size: [%zd]\n",
1433 crypt_stat->num_header_bytes_at_front);
1439 * set_default_header_data
1440 * @crypt_stat: The cryptographic context
1442 * For version 0 file format; this function is only for backwards
1443 * compatibility for files created with the prior versions of
1446 static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1448 crypt_stat->num_header_bytes_at_front =
1449 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
1453 * ecryptfs_read_headers_virt
1454 * @page_virt: The virtual address into which to read the headers
1455 * @crypt_stat: The cryptographic context
1456 * @ecryptfs_dentry: The eCryptfs dentry
1457 * @validate_header_size: Whether to validate the header size while reading
1459 * Read/parse the header data. The header format is detailed in the
1460 * comment block for the ecryptfs_write_headers_virt() function.
1462 * Returns zero on success
1464 static int ecryptfs_read_headers_virt(char *page_virt,
1465 struct ecryptfs_crypt_stat *crypt_stat,
1466 struct dentry *ecryptfs_dentry,
1467 int validate_header_size)
1473 ecryptfs_set_default_sizes(crypt_stat);
1474 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1475 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1476 offset = ECRYPTFS_FILE_SIZE_BYTES;
1477 rc = contains_ecryptfs_marker(page_virt + offset);
1482 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1483 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1486 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1489 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1490 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1491 "file version [%d] is supported by this "
1492 "version of eCryptfs\n",
1493 crypt_stat->file_version,
1494 ECRYPTFS_SUPPORTED_FILE_VERSION);
1498 offset += bytes_read;
1499 if (crypt_stat->file_version >= 1) {
1500 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
1501 &bytes_read, validate_header_size);
1503 ecryptfs_printk(KERN_WARNING, "Error reading header "
1504 "metadata; rc = [%d]\n", rc);
1506 offset += bytes_read;
1508 set_default_header_data(crypt_stat);
1509 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1516 * ecryptfs_read_xattr_region
1517 * @page_virt: The vitual address into which to read the xattr data
1518 * @ecryptfs_inode: The eCryptfs inode
1520 * Attempts to read the crypto metadata from the extended attribute
1521 * region of the lower file.
1523 * Returns zero on success; non-zero on error
1525 int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
1527 struct dentry *lower_dentry =
1528 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
1532 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1533 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
1535 if (unlikely(ecryptfs_verbosity > 0))
1536 printk(KERN_INFO "Error attempting to read the [%s] "
1537 "xattr from the lower file; return value = "
1538 "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
1546 int ecryptfs_read_and_validate_xattr_region(char *page_virt,
1547 struct dentry *ecryptfs_dentry)
1551 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
1554 if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
1555 printk(KERN_WARNING "Valid data found in [%s] xattr, but "
1556 "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
1564 * ecryptfs_read_metadata
1566 * Common entry point for reading file metadata. From here, we could
1567 * retrieve the header information from the header region of the file,
1568 * the xattr region of the file, or some other repostory that is
1569 * stored separately from the file itself. The current implementation
1570 * supports retrieving the metadata information from the file contents
1571 * and from the xattr region.
1573 * Returns zero if valid headers found and parsed; non-zero otherwise
1575 int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
1578 char *page_virt = NULL;
1579 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
1580 struct ecryptfs_crypt_stat *crypt_stat =
1581 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1582 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1583 &ecryptfs_superblock_to_private(
1584 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1586 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1588 /* Read the first page from the underlying file */
1589 page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
1592 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
1596 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1599 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1601 ECRYPTFS_VALIDATE_HEADER_SIZE);
1603 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
1605 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1606 "file header region or xattr region\n");
1610 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1612 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1614 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1615 "file xattr region either\n");
1618 if (crypt_stat->mount_crypt_stat->flags
1619 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1620 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1622 printk(KERN_WARNING "Attempt to access file with "
1623 "crypto metadata only in the extended attribute "
1624 "region, but eCryptfs was mounted without "
1625 "xattr support enabled. eCryptfs will not treat "
1626 "this like an encrypted file.\n");
1632 memset(page_virt, 0, PAGE_CACHE_SIZE);
1633 kmem_cache_free(ecryptfs_header_cache_1, page_virt);
1639 * ecryptfs_encrypt_filename - encrypt filename
1641 * CBC-encrypts the filename. We do not want to encrypt the same
1642 * filename with the same key and IV, which may happen with hard
1643 * links, so we prepend random bits to each filename.
1645 * Returns zero on success; non-zero otherwise
1648 ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1649 struct ecryptfs_crypt_stat *crypt_stat,
1650 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1654 filename->encrypted_filename = NULL;
1655 filename->encrypted_filename_size = 0;
1656 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
1657 || (mount_crypt_stat && (mount_crypt_stat->flags
1658 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
1660 size_t remaining_bytes;
1662 rc = ecryptfs_write_tag_70_packet(
1664 &filename->encrypted_filename_size,
1665 mount_crypt_stat, NULL,
1666 filename->filename_size);
1668 printk(KERN_ERR "%s: Error attempting to get packet "
1669 "size for tag 72; rc = [%d]\n", __func__,
1671 filename->encrypted_filename_size = 0;
1674 filename->encrypted_filename =
1675 kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1676 if (!filename->encrypted_filename) {
1677 printk(KERN_ERR "%s: Out of memory whilst attempting "
1678 "to kmalloc [%zd] bytes\n", __func__,
1679 filename->encrypted_filename_size);
1683 remaining_bytes = filename->encrypted_filename_size;
1684 rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
1689 filename->filename_size);
1691 printk(KERN_ERR "%s: Error attempting to generate "
1692 "tag 70 packet; rc = [%d]\n", __func__,
1694 kfree(filename->encrypted_filename);
1695 filename->encrypted_filename = NULL;
1696 filename->encrypted_filename_size = 0;
1699 filename->encrypted_filename_size = packet_size;
1701 printk(KERN_ERR "%s: No support for requested filename "
1702 "encryption method in this release\n", __func__);
1710 static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1711 const char *name, size_t name_size)
1715 (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
1716 if (!(*copied_name)) {
1720 memcpy((void *)(*copied_name), (void *)name, name_size);
1721 (*copied_name)[(name_size)] = '\0'; /* Only for convenience
1722 * in printing out the
1725 (*copied_name_size) = name_size;
1731 * ecryptfs_process_key_cipher - Perform key cipher initialization.
1732 * @key_tfm: Crypto context for key material, set by this function
1733 * @cipher_name: Name of the cipher
1734 * @key_size: Size of the key in bytes
1736 * Returns zero on success. Any crypto_tfm structs allocated here
1737 * should be released by other functions, such as on a superblock put
1738 * event, regardless of whether this function succeeds for fails.
1741 ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1742 char *cipher_name, size_t *key_size)
1744 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
1745 char *full_alg_name;
1749 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
1751 printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
1752 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
1755 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1759 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1760 kfree(full_alg_name);
1761 if (IS_ERR(*key_tfm)) {
1762 rc = PTR_ERR(*key_tfm);
1763 printk(KERN_ERR "Unable to allocate crypto cipher with name "
1764 "[%s]; rc = [%d]\n", cipher_name, rc);
1767 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1768 if (*key_size == 0) {
1769 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1771 *key_size = alg->max_keysize;
1773 get_random_bytes(dummy_key, *key_size);
1774 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
1776 printk(KERN_ERR "Error attempting to set key of size [%zd] for "
1777 "cipher [%s]; rc = [%d]\n", *key_size, cipher_name, rc);
1785 struct kmem_cache *ecryptfs_key_tfm_cache;
1786 static struct list_head key_tfm_list;
1787 struct mutex key_tfm_list_mutex;
1789 int ecryptfs_init_crypto(void)
1791 mutex_init(&key_tfm_list_mutex);
1792 INIT_LIST_HEAD(&key_tfm_list);
1797 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1799 * Called only at module unload time
1801 int ecryptfs_destroy_crypto(void)
1803 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1805 mutex_lock(&key_tfm_list_mutex);
1806 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1808 list_del(&key_tfm->key_tfm_list);
1809 if (key_tfm->key_tfm)
1810 crypto_free_blkcipher(key_tfm->key_tfm);
1811 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1813 mutex_unlock(&key_tfm_list_mutex);
1818 ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1821 struct ecryptfs_key_tfm *tmp_tfm;
1824 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1826 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1827 if (key_tfm != NULL)
1828 (*key_tfm) = tmp_tfm;
1831 printk(KERN_ERR "Error attempting to allocate from "
1832 "ecryptfs_key_tfm_cache\n");
1835 mutex_init(&tmp_tfm->key_tfm_mutex);
1836 strncpy(tmp_tfm->cipher_name, cipher_name,
1837 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
1838 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
1839 tmp_tfm->key_size = key_size;
1840 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1841 tmp_tfm->cipher_name,
1842 &tmp_tfm->key_size);
1844 printk(KERN_ERR "Error attempting to initialize key TFM "
1845 "cipher with name = [%s]; rc = [%d]\n",
1846 tmp_tfm->cipher_name, rc);
1847 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1848 if (key_tfm != NULL)
1852 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
1858 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1859 * @cipher_name: the name of the cipher to search for
1860 * @key_tfm: set to corresponding tfm if found
1862 * Searches for cached key_tfm matching @cipher_name
1863 * Must be called with &key_tfm_list_mutex held
1864 * Returns 1 if found, with @key_tfm set
1865 * Returns 0 if not found, with @key_tfm set to NULL
1867 int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1869 struct ecryptfs_key_tfm *tmp_key_tfm;
1871 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1873 list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1874 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1876 (*key_tfm) = tmp_key_tfm;
1886 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1888 * @tfm: set to cached tfm found, or new tfm created
1889 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1890 * @cipher_name: the name of the cipher to search for and/or add
1892 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1893 * Searches for cached item first, and creates new if not found.
1894 * Returns 0 on success, non-zero if adding new cipher failed
1896 int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1897 struct mutex **tfm_mutex,
1900 struct ecryptfs_key_tfm *key_tfm;
1904 (*tfm_mutex) = NULL;
1906 mutex_lock(&key_tfm_list_mutex);
1907 if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1908 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1910 printk(KERN_ERR "Error adding new key_tfm to list; "
1915 (*tfm) = key_tfm->key_tfm;
1916 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1918 mutex_unlock(&key_tfm_list_mutex);
1922 /* 64 characters forming a 6-bit target field */
1923 static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1926 "klmnopqrstuvwxyz");
1928 /* We could either offset on every reverse map or just pad some 0x00's
1929 * at the front here */
1930 static const unsigned char filename_rev_map[] = {
1931 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1932 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1933 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1934 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1935 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1936 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1937 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1938 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1939 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1940 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1941 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1942 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1943 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1944 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1945 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
1950 * ecryptfs_encode_for_filename
1951 * @dst: Destination location for encoded filename
1952 * @dst_size: Size of the encoded filename in bytes
1953 * @src: Source location for the filename to encode
1954 * @src_size: Size of the source in bytes
1956 void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
1957 unsigned char *src, size_t src_size)
1960 size_t block_num = 0;
1961 size_t dst_offset = 0;
1962 unsigned char last_block[3];
1964 if (src_size == 0) {
1968 num_blocks = (src_size / 3);
1969 if ((src_size % 3) == 0) {
1970 memcpy(last_block, (&src[src_size - 3]), 3);
1973 last_block[2] = 0x00;
1974 switch (src_size % 3) {
1976 last_block[0] = src[src_size - 1];
1977 last_block[1] = 0x00;
1980 last_block[0] = src[src_size - 2];
1981 last_block[1] = src[src_size - 1];
1984 (*dst_size) = (num_blocks * 4);
1987 while (block_num < num_blocks) {
1988 unsigned char *src_block;
1989 unsigned char dst_block[4];
1991 if (block_num == (num_blocks - 1))
1992 src_block = last_block;
1994 src_block = &src[block_num * 3];
1995 dst_block[0] = ((src_block[0] >> 2) & 0x3F);
1996 dst_block[1] = (((src_block[0] << 4) & 0x30)
1997 | ((src_block[1] >> 4) & 0x0F));
1998 dst_block[2] = (((src_block[1] << 2) & 0x3C)
1999 | ((src_block[2] >> 6) & 0x03));
2000 dst_block[3] = (src_block[2] & 0x3F);
2001 dst[dst_offset++] = portable_filename_chars[dst_block[0]];
2002 dst[dst_offset++] = portable_filename_chars[dst_block[1]];
2003 dst[dst_offset++] = portable_filename_chars[dst_block[2]];
2004 dst[dst_offset++] = portable_filename_chars[dst_block[3]];
2012 * ecryptfs_decode_from_filename
2013 * @dst: If NULL, this function only sets @dst_size and returns. If
2014 * non-NULL, this function decodes the encoded octets in @src
2015 * into the memory that @dst points to.
2016 * @dst_size: Set to the size of the decoded string.
2017 * @src: The encoded set of octets to decode.
2018 * @src_size: The size of the encoded set of octets to decode.
2021 ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
2022 const unsigned char *src, size_t src_size)
2024 u8 current_bit_offset = 0;
2025 size_t src_byte_offset = 0;
2026 size_t dst_byte_offset = 0;
2029 /* Not exact; conservatively long. Every block of 4
2030 * encoded characters decodes into a block of 3
2031 * decoded characters. This segment of code provides
2032 * the caller with the maximum amount of allocated
2033 * space that @dst will need to point to in a
2034 * subsequent call. */
2035 (*dst_size) = (((src_size + 1) * 3) / 4);
2038 while (src_byte_offset < src_size) {
2039 unsigned char src_byte =
2040 filename_rev_map[(int)src[src_byte_offset]];
2042 switch (current_bit_offset) {
2044 dst[dst_byte_offset] = (src_byte << 2);
2045 current_bit_offset = 6;
2048 dst[dst_byte_offset++] |= (src_byte >> 4);
2049 dst[dst_byte_offset] = ((src_byte & 0xF)
2051 current_bit_offset = 4;
2054 dst[dst_byte_offset++] |= (src_byte >> 2);
2055 dst[dst_byte_offset] = (src_byte << 6);
2056 current_bit_offset = 2;
2059 dst[dst_byte_offset++] |= (src_byte);
2060 dst[dst_byte_offset] = 0;
2061 current_bit_offset = 0;
2066 (*dst_size) = dst_byte_offset;
2072 * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
2073 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
2074 * @name: The plaintext name
2075 * @length: The length of the plaintext
2076 * @encoded_name: The encypted name
2078 * Encrypts and encodes a filename into something that constitutes a
2079 * valid filename for a filesystem, with printable characters.
2081 * We assume that we have a properly initialized crypto context,
2082 * pointed to by crypt_stat->tfm.
2084 * Returns zero on success; non-zero on otherwise
2086 int ecryptfs_encrypt_and_encode_filename(
2087 char **encoded_name,
2088 size_t *encoded_name_size,
2089 struct ecryptfs_crypt_stat *crypt_stat,
2090 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2091 const char *name, size_t name_size)
2093 size_t encoded_name_no_prefix_size;
2096 (*encoded_name) = NULL;
2097 (*encoded_name_size) = 0;
2098 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
2099 || (mount_crypt_stat && (mount_crypt_stat->flags
2100 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) {
2101 struct ecryptfs_filename *filename;
2103 filename = kzalloc(sizeof(*filename), GFP_KERNEL);
2105 printk(KERN_ERR "%s: Out of memory whilst attempting "
2106 "to kzalloc [%zd] bytes\n", __func__,
2111 filename->filename = (char *)name;
2112 filename->filename_size = name_size;
2113 rc = ecryptfs_encrypt_filename(filename, crypt_stat,
2116 printk(KERN_ERR "%s: Error attempting to encrypt "
2117 "filename; rc = [%d]\n", __func__, rc);
2121 ecryptfs_encode_for_filename(
2122 NULL, &encoded_name_no_prefix_size,
2123 filename->encrypted_filename,
2124 filename->encrypted_filename_size);
2125 if ((crypt_stat && (crypt_stat->flags
2126 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2127 || (mount_crypt_stat
2128 && (mount_crypt_stat->flags
2129 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)))
2130 (*encoded_name_size) =
2131 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2132 + encoded_name_no_prefix_size);
2134 (*encoded_name_size) =
2135 (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2136 + encoded_name_no_prefix_size);
2137 (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
2138 if (!(*encoded_name)) {
2139 printk(KERN_ERR "%s: Out of memory whilst attempting "
2140 "to kzalloc [%zd] bytes\n", __func__,
2141 (*encoded_name_size));
2143 kfree(filename->encrypted_filename);
2147 if ((crypt_stat && (crypt_stat->flags
2148 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2149 || (mount_crypt_stat
2150 && (mount_crypt_stat->flags
2151 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
2152 memcpy((*encoded_name),
2153 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2154 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
2155 ecryptfs_encode_for_filename(
2157 + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
2158 &encoded_name_no_prefix_size,
2159 filename->encrypted_filename,
2160 filename->encrypted_filename_size);
2161 (*encoded_name_size) =
2162 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2163 + encoded_name_no_prefix_size);
2164 (*encoded_name)[(*encoded_name_size)] = '\0';
2165 (*encoded_name_size)++;
2170 printk(KERN_ERR "%s: Error attempting to encode "
2171 "encrypted filename; rc = [%d]\n", __func__,
2173 kfree((*encoded_name));
2174 (*encoded_name) = NULL;
2175 (*encoded_name_size) = 0;
2177 kfree(filename->encrypted_filename);
2180 rc = ecryptfs_copy_filename(encoded_name,
2189 * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
2190 * @plaintext_name: The plaintext name
2191 * @plaintext_name_size: The plaintext name size
2192 * @ecryptfs_dir_dentry: eCryptfs directory dentry
2193 * @name: The filename in cipher text
2194 * @name_size: The cipher text name size
2196 * Decrypts and decodes the filename.
2198 * Returns zero on error; non-zero otherwise
2200 int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
2201 size_t *plaintext_name_size,
2202 struct dentry *ecryptfs_dir_dentry,
2203 const char *name, size_t name_size)
2205 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2206 &ecryptfs_superblock_to_private(
2207 ecryptfs_dir_dentry->d_sb)->mount_crypt_stat;
2209 size_t decoded_name_size;
2213 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
2214 && !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
2215 && (name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
2216 && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2217 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
2218 const char *orig_name = name;
2219 size_t orig_name_size = name_size;
2221 name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2222 name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2223 ecryptfs_decode_from_filename(NULL, &decoded_name_size,
2225 decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
2226 if (!decoded_name) {
2227 printk(KERN_ERR "%s: Out of memory whilst attempting "
2228 "to kmalloc [%zd] bytes\n", __func__,
2233 ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
2235 rc = ecryptfs_parse_tag_70_packet(plaintext_name,
2236 plaintext_name_size,
2242 printk(KERN_INFO "%s: Could not parse tag 70 packet "
2243 "from filename; copying through filename "
2244 "as-is\n", __func__);
2245 rc = ecryptfs_copy_filename(plaintext_name,
2246 plaintext_name_size,
2247 orig_name, orig_name_size);
2251 rc = ecryptfs_copy_filename(plaintext_name,
2252 plaintext_name_size,
2257 kfree(decoded_name);