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]"
521 if (enc_extent_page) {
522 kunmap(enc_extent_page);
523 __free_page(enc_extent_page);
528 static int ecryptfs_decrypt_extent(struct page *page,
529 struct ecryptfs_crypt_stat *crypt_stat,
530 struct page *enc_extent_page,
531 unsigned long extent_offset)
534 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
537 extent_base = (((loff_t)page->index)
538 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
539 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
540 (extent_base + extent_offset));
542 ecryptfs_printk(KERN_ERR, "Error attempting to "
543 "derive IV for extent [0x%.16x]; "
544 "rc = [%d]\n", (extent_base + extent_offset),
548 if (unlikely(ecryptfs_verbosity > 0)) {
549 ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
551 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
552 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
554 ecryptfs_dump_hex((char *)
555 (page_address(enc_extent_page)
556 + (extent_offset * crypt_stat->extent_size)),
559 rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
561 * crypt_stat->extent_size),
563 crypt_stat->extent_size, extent_iv);
565 printk(KERN_ERR "%s: Error attempting to decrypt to page with "
566 "page->index = [%ld], extent_offset = [%ld]; "
567 "rc = [%d]\n", __func__, page->index, extent_offset,
572 if (unlikely(ecryptfs_verbosity > 0)) {
573 ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16x]; "
574 "rc = [%d]\n", (extent_base + extent_offset),
576 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
578 ecryptfs_dump_hex((char *)(page_address(page)
580 * crypt_stat->extent_size)), 8);
587 * ecryptfs_decrypt_page
588 * @page: Page mapped from the eCryptfs inode for the file; data read
589 * and decrypted from the lower file will be written into this
592 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
593 * that eCryptfs pages may straddle the lower pages -- for instance,
594 * if the file was created on a machine with an 8K page size
595 * (resulting in an 8K header), and then the file is copied onto a
596 * host with a 32K page size, then when reading page 0 of the eCryptfs
597 * file, 24K of page 0 of the lower file will be read and decrypted,
598 * and then 8K of page 1 of the lower file will be read and decrypted.
600 * Returns zero on success; negative on error
602 int ecryptfs_decrypt_page(struct page *page)
604 struct inode *ecryptfs_inode;
605 struct ecryptfs_crypt_stat *crypt_stat;
606 char *enc_extent_virt;
607 struct page *enc_extent_page = NULL;
608 unsigned long extent_offset;
611 ecryptfs_inode = page->mapping->host;
613 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
614 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
615 enc_extent_page = alloc_page(GFP_USER);
616 if (!enc_extent_page) {
618 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
619 "encrypted extent\n");
622 enc_extent_virt = kmap(enc_extent_page);
623 for (extent_offset = 0;
624 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
628 ecryptfs_lower_offset_for_extent(
629 &offset, ((page->index * (PAGE_CACHE_SIZE
630 / crypt_stat->extent_size))
631 + extent_offset), crypt_stat);
632 rc = ecryptfs_read_lower(enc_extent_virt, offset,
633 crypt_stat->extent_size,
636 ecryptfs_printk(KERN_ERR, "Error attempting "
637 "to read lower page; rc = [%d]"
641 rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
644 printk(KERN_ERR "%s: Error encrypting extent; "
645 "rc = [%d]\n", __func__, rc);
650 if (enc_extent_page) {
651 kunmap(enc_extent_page);
652 __free_page(enc_extent_page);
658 * decrypt_scatterlist
659 * @crypt_stat: Cryptographic context
660 * @dest_sg: The destination scatterlist to decrypt into
661 * @src_sg: The source scatterlist to decrypt from
662 * @size: The number of bytes to decrypt
663 * @iv: The initialization vector to use for the decryption
665 * Returns the number of bytes decrypted; negative value on error
667 static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
668 struct scatterlist *dest_sg,
669 struct scatterlist *src_sg, int size,
672 struct blkcipher_desc desc = {
673 .tfm = crypt_stat->tfm,
675 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
679 /* Consider doing this once, when the file is opened */
680 mutex_lock(&crypt_stat->cs_tfm_mutex);
681 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
682 crypt_stat->key_size);
684 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
686 mutex_unlock(&crypt_stat->cs_tfm_mutex);
690 ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
691 rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size);
692 mutex_unlock(&crypt_stat->cs_tfm_mutex);
694 ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n",
704 * ecryptfs_encrypt_page_offset
705 * @crypt_stat: The cryptographic context
706 * @dst_page: The page to encrypt into
707 * @dst_offset: The offset in the page to encrypt into
708 * @src_page: The page to encrypt from
709 * @src_offset: The offset in the page to encrypt from
710 * @size: The number of bytes to encrypt
711 * @iv: The initialization vector to use for the encryption
713 * Returns the number of bytes encrypted
716 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
717 struct page *dst_page, int dst_offset,
718 struct page *src_page, int src_offset, int size,
721 struct scatterlist src_sg, dst_sg;
723 sg_init_table(&src_sg, 1);
724 sg_init_table(&dst_sg, 1);
726 sg_set_page(&src_sg, src_page, size, src_offset);
727 sg_set_page(&dst_sg, dst_page, size, dst_offset);
728 return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
732 * ecryptfs_decrypt_page_offset
733 * @crypt_stat: The cryptographic context
734 * @dst_page: The page to decrypt into
735 * @dst_offset: The offset in the page to decrypt into
736 * @src_page: The page to decrypt from
737 * @src_offset: The offset in the page to decrypt from
738 * @size: The number of bytes to decrypt
739 * @iv: The initialization vector to use for the decryption
741 * Returns the number of bytes decrypted
744 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
745 struct page *dst_page, int dst_offset,
746 struct page *src_page, int src_offset, int size,
749 struct scatterlist src_sg, dst_sg;
751 sg_init_table(&src_sg, 1);
752 sg_set_page(&src_sg, src_page, size, src_offset);
754 sg_init_table(&dst_sg, 1);
755 sg_set_page(&dst_sg, dst_page, size, dst_offset);
757 return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
760 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
763 * ecryptfs_init_crypt_ctx
764 * @crypt_stat: Uninitilized crypt stats structure
766 * Initialize the crypto context.
768 * TODO: Performance: Keep a cache of initialized cipher contexts;
769 * only init if needed
771 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
776 if (!crypt_stat->cipher) {
777 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
780 ecryptfs_printk(KERN_DEBUG,
781 "Initializing cipher [%s]; strlen = [%d]; "
782 "key_size_bits = [%d]\n",
783 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
784 crypt_stat->key_size << 3);
785 if (crypt_stat->tfm) {
789 mutex_lock(&crypt_stat->cs_tfm_mutex);
790 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
791 crypt_stat->cipher, "cbc");
794 crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
796 kfree(full_alg_name);
797 if (IS_ERR(crypt_stat->tfm)) {
798 rc = PTR_ERR(crypt_stat->tfm);
799 crypt_stat->tfm = NULL;
800 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
801 "Error initializing cipher [%s]\n",
805 crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
808 mutex_unlock(&crypt_stat->cs_tfm_mutex);
813 static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
817 crypt_stat->extent_mask = 0xFFFFFFFF;
818 crypt_stat->extent_shift = 0;
819 if (crypt_stat->extent_size == 0)
821 extent_size_tmp = crypt_stat->extent_size;
822 while ((extent_size_tmp & 0x01) == 0) {
823 extent_size_tmp >>= 1;
824 crypt_stat->extent_mask <<= 1;
825 crypt_stat->extent_shift++;
829 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
831 /* Default values; may be overwritten as we are parsing the
833 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
834 set_extent_mask_and_shift(crypt_stat);
835 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
836 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
837 crypt_stat->num_header_bytes_at_front = 0;
839 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
840 crypt_stat->num_header_bytes_at_front =
841 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
843 crypt_stat->num_header_bytes_at_front = PAGE_CACHE_SIZE;
848 * ecryptfs_compute_root_iv
851 * On error, sets the root IV to all 0's.
853 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
856 char dst[MD5_DIGEST_SIZE];
858 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
859 BUG_ON(crypt_stat->iv_bytes <= 0);
860 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
862 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
863 "cannot generate root IV\n");
866 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
867 crypt_stat->key_size);
869 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
870 "MD5 while generating root IV\n");
873 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
876 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
877 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
882 static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
884 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
885 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
886 ecryptfs_compute_root_iv(crypt_stat);
887 if (unlikely(ecryptfs_verbosity > 0)) {
888 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
889 ecryptfs_dump_hex(crypt_stat->key,
890 crypt_stat->key_size);
895 * ecryptfs_copy_mount_wide_flags_to_inode_flags
896 * @crypt_stat: The inode's cryptographic context
897 * @mount_crypt_stat: The mount point's cryptographic context
899 * This function propagates the mount-wide flags to individual inode
902 static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
903 struct ecryptfs_crypt_stat *crypt_stat,
904 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
906 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
907 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
908 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
909 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
910 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
911 crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
912 if (mount_crypt_stat->flags
913 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
914 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
915 else if (mount_crypt_stat->flags
916 & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
917 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
921 static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
922 struct ecryptfs_crypt_stat *crypt_stat,
923 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
925 struct ecryptfs_global_auth_tok *global_auth_tok;
928 mutex_lock(&crypt_stat->keysig_list_mutex);
929 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
931 list_for_each_entry(global_auth_tok,
932 &mount_crypt_stat->global_auth_tok_list,
933 mount_crypt_stat_list) {
934 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
936 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
938 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
944 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
945 mutex_unlock(&crypt_stat->keysig_list_mutex);
950 * ecryptfs_set_default_crypt_stat_vals
951 * @crypt_stat: The inode's cryptographic context
952 * @mount_crypt_stat: The mount point's cryptographic context
954 * Default values in the event that policy does not override them.
956 static void ecryptfs_set_default_crypt_stat_vals(
957 struct ecryptfs_crypt_stat *crypt_stat,
958 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
960 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
962 ecryptfs_set_default_sizes(crypt_stat);
963 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
964 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
965 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
966 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
967 crypt_stat->mount_crypt_stat = mount_crypt_stat;
971 * ecryptfs_new_file_context
972 * @ecryptfs_dentry: The eCryptfs dentry
974 * If the crypto context for the file has not yet been established,
975 * this is where we do that. Establishing a new crypto context
976 * involves the following decisions:
977 * - What cipher to use?
978 * - What set of authentication tokens to use?
979 * Here we just worry about getting enough information into the
980 * authentication tokens so that we know that they are available.
981 * We associate the available authentication tokens with the new file
982 * via the set of signatures in the crypt_stat struct. Later, when
983 * the headers are actually written out, we may again defer to
984 * userspace to perform the encryption of the session key; for the
985 * foreseeable future, this will be the case with public key packets.
987 * Returns zero on success; non-zero otherwise
989 int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
991 struct ecryptfs_crypt_stat *crypt_stat =
992 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
993 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
994 &ecryptfs_superblock_to_private(
995 ecryptfs_dentry->d_sb)->mount_crypt_stat;
999 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
1000 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
1001 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1003 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
1006 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
1007 "to the inode key sigs; rc = [%d]\n", rc);
1011 strlen(mount_crypt_stat->global_default_cipher_name);
1012 memcpy(crypt_stat->cipher,
1013 mount_crypt_stat->global_default_cipher_name,
1015 crypt_stat->cipher[cipher_name_len] = '\0';
1016 crypt_stat->key_size =
1017 mount_crypt_stat->global_default_cipher_key_size;
1018 ecryptfs_generate_new_key(crypt_stat);
1019 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1021 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
1022 "context for cipher [%s]: rc = [%d]\n",
1023 crypt_stat->cipher, rc);
1029 * contains_ecryptfs_marker - check for the ecryptfs marker
1030 * @data: The data block in which to check
1032 * Returns one if marker found; zero if not found
1034 static int contains_ecryptfs_marker(char *data)
1038 m_1 = get_unaligned_be32(data);
1039 m_2 = get_unaligned_be32(data + 4);
1040 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
1042 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1043 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1044 MAGIC_ECRYPTFS_MARKER);
1045 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1046 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1050 struct ecryptfs_flag_map_elem {
1055 /* Add support for additional flags by adding elements here. */
1056 static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1057 {0x00000001, ECRYPTFS_ENABLE_HMAC},
1058 {0x00000002, ECRYPTFS_ENCRYPTED},
1059 {0x00000004, ECRYPTFS_METADATA_IN_XATTR},
1060 {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
1064 * ecryptfs_process_flags
1065 * @crypt_stat: The cryptographic context
1066 * @page_virt: Source data to be parsed
1067 * @bytes_read: Updated with the number of bytes read
1069 * Returns zero on success; non-zero if the flag set is invalid
1071 static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1072 char *page_virt, int *bytes_read)
1078 flags = get_unaligned_be32(page_virt);
1079 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1080 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1081 if (flags & ecryptfs_flag_map[i].file_flag) {
1082 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
1084 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
1085 /* Version is in top 8 bits of the 32-bit flag vector */
1086 crypt_stat->file_version = ((flags >> 24) & 0xFF);
1092 * write_ecryptfs_marker
1093 * @page_virt: The pointer to in a page to begin writing the marker
1094 * @written: Number of bytes written
1096 * Marker = 0x3c81b7f5
1098 static void write_ecryptfs_marker(char *page_virt, size_t *written)
1102 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1103 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
1104 put_unaligned_be32(m_1, page_virt);
1105 page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
1106 put_unaligned_be32(m_2, page_virt);
1107 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1111 write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat,
1117 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1118 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1119 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
1120 flags |= ecryptfs_flag_map[i].file_flag;
1121 /* Version is in top 8 bits of the 32-bit flag vector */
1122 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
1123 put_unaligned_be32(flags, page_virt);
1127 struct ecryptfs_cipher_code_str_map_elem {
1128 char cipher_str[16];
1132 /* Add support for additional ciphers by adding elements here. The
1133 * cipher_code is whatever OpenPGP applicatoins use to identify the
1134 * ciphers. List in order of probability. */
1135 static struct ecryptfs_cipher_code_str_map_elem
1136 ecryptfs_cipher_code_str_map[] = {
1137 {"aes",RFC2440_CIPHER_AES_128 },
1138 {"blowfish", RFC2440_CIPHER_BLOWFISH},
1139 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1140 {"cast5", RFC2440_CIPHER_CAST_5},
1141 {"twofish", RFC2440_CIPHER_TWOFISH},
1142 {"cast6", RFC2440_CIPHER_CAST_6},
1143 {"aes", RFC2440_CIPHER_AES_192},
1144 {"aes", RFC2440_CIPHER_AES_256}
1148 * ecryptfs_code_for_cipher_string
1149 * @cipher_name: The string alias for the cipher
1150 * @key_bytes: Length of key in bytes; used for AES code selection
1152 * Returns zero on no match, or the cipher code on match
1154 u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
1158 struct ecryptfs_cipher_code_str_map_elem *map =
1159 ecryptfs_cipher_code_str_map;
1161 if (strcmp(cipher_name, "aes") == 0) {
1162 switch (key_bytes) {
1164 code = RFC2440_CIPHER_AES_128;
1167 code = RFC2440_CIPHER_AES_192;
1170 code = RFC2440_CIPHER_AES_256;
1173 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1174 if (strcmp(cipher_name, map[i].cipher_str) == 0) {
1175 code = map[i].cipher_code;
1183 * ecryptfs_cipher_code_to_string
1184 * @str: Destination to write out the cipher name
1185 * @cipher_code: The code to convert to cipher name string
1187 * Returns zero on success
1189 int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
1195 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1196 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1197 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1198 if (str[0] == '\0') {
1199 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1200 "[%d]\n", cipher_code);
1206 int ecryptfs_read_and_validate_header_region(char *data,
1207 struct inode *ecryptfs_inode)
1209 struct ecryptfs_crypt_stat *crypt_stat =
1210 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
1213 if (crypt_stat->extent_size == 0)
1214 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
1215 rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
1218 printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
1222 if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) {
1231 ecryptfs_write_header_metadata(char *virt,
1232 struct ecryptfs_crypt_stat *crypt_stat,
1235 u32 header_extent_size;
1236 u16 num_header_extents_at_front;
1238 header_extent_size = (u32)crypt_stat->extent_size;
1239 num_header_extents_at_front =
1240 (u16)(crypt_stat->num_header_bytes_at_front
1241 / crypt_stat->extent_size);
1242 put_unaligned_be32(header_extent_size, virt);
1244 put_unaligned_be16(num_header_extents_at_front, virt);
1248 struct kmem_cache *ecryptfs_header_cache_1;
1249 struct kmem_cache *ecryptfs_header_cache_2;
1252 * ecryptfs_write_headers_virt
1253 * @page_virt: The virtual address to write the headers to
1254 * @max: The size of memory allocated at page_virt
1255 * @size: Set to the number of bytes written by this function
1256 * @crypt_stat: The cryptographic context
1257 * @ecryptfs_dentry: The eCryptfs dentry
1262 * Octets 0-7: Unencrypted file size (big-endian)
1263 * Octets 8-15: eCryptfs special marker
1264 * Octets 16-19: Flags
1265 * Octet 16: File format version number (between 0 and 255)
1266 * Octets 17-18: Reserved
1267 * Octet 19: Bit 1 (lsb): Reserved
1269 * Bits 3-8: Reserved
1270 * Octets 20-23: Header extent size (big-endian)
1271 * Octets 24-25: Number of header extents at front of file
1273 * Octet 26: Begin RFC 2440 authentication token packet set
1275 * Lower data (CBC encrypted)
1277 * Lower data (CBC encrypted)
1280 * Returns zero on success
1282 static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1284 struct ecryptfs_crypt_stat *crypt_stat,
1285 struct dentry *ecryptfs_dentry)
1291 offset = ECRYPTFS_FILE_SIZE_BYTES;
1292 write_ecryptfs_marker((page_virt + offset), &written);
1294 write_ecryptfs_flags((page_virt + offset), crypt_stat, &written);
1296 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1299 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1300 ecryptfs_dentry, &written,
1303 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1304 "set; rc = [%d]\n", rc);
1313 ecryptfs_write_metadata_to_contents(struct dentry *ecryptfs_dentry,
1314 char *virt, size_t virt_len)
1318 rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, virt,
1321 printk(KERN_ERR "%s: Error attempting to write header "
1322 "information to lower file; rc = [%d]\n", __func__, rc);
1329 ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1330 char *page_virt, size_t size)
1334 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1339 static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1344 page = alloc_pages(gfp_mask | __GFP_ZERO, order);
1346 return (unsigned long) page_address(page);
1351 * ecryptfs_write_metadata
1352 * @ecryptfs_dentry: The eCryptfs dentry
1354 * Write the file headers out. This will likely involve a userspace
1355 * callout, in which the session key is encrypted with one or more
1356 * public keys and/or the passphrase necessary to do the encryption is
1357 * retrieved via a prompt. Exactly what happens at this point should
1358 * be policy-dependent.
1360 * Returns zero on success; non-zero on error
1362 int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
1364 struct ecryptfs_crypt_stat *crypt_stat =
1365 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
1372 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1373 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
1374 printk(KERN_ERR "Key is invalid; bailing out\n");
1379 printk(KERN_WARNING "%s: Encrypted flag not set\n",
1384 virt_len = crypt_stat->num_header_bytes_at_front;
1385 order = get_order(virt_len);
1386 /* Released in this function */
1387 virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
1389 printk(KERN_ERR "%s: Out of memory\n", __func__);
1393 rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
1396 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
1400 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1401 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt,
1404 rc = ecryptfs_write_metadata_to_contents(ecryptfs_dentry, virt,
1407 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
1408 "rc = [%d]\n", __func__, rc);
1412 free_pages((unsigned long)virt, order);
1417 #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1418 #define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1419 static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
1420 char *virt, int *bytes_read,
1421 int validate_header_size)
1424 u32 header_extent_size;
1425 u16 num_header_extents_at_front;
1427 header_extent_size = get_unaligned_be32(virt);
1428 virt += sizeof(__be32);
1429 num_header_extents_at_front = get_unaligned_be16(virt);
1430 crypt_stat->num_header_bytes_at_front =
1431 (((size_t)num_header_extents_at_front
1432 * (size_t)header_extent_size));
1433 (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
1434 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
1435 && (crypt_stat->num_header_bytes_at_front
1436 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
1438 printk(KERN_WARNING "Invalid header size: [%zd]\n",
1439 crypt_stat->num_header_bytes_at_front);
1445 * set_default_header_data
1446 * @crypt_stat: The cryptographic context
1448 * For version 0 file format; this function is only for backwards
1449 * compatibility for files created with the prior versions of
1452 static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1454 crypt_stat->num_header_bytes_at_front =
1455 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
1459 * ecryptfs_read_headers_virt
1460 * @page_virt: The virtual address into which to read the headers
1461 * @crypt_stat: The cryptographic context
1462 * @ecryptfs_dentry: The eCryptfs dentry
1463 * @validate_header_size: Whether to validate the header size while reading
1465 * Read/parse the header data. The header format is detailed in the
1466 * comment block for the ecryptfs_write_headers_virt() function.
1468 * Returns zero on success
1470 static int ecryptfs_read_headers_virt(char *page_virt,
1471 struct ecryptfs_crypt_stat *crypt_stat,
1472 struct dentry *ecryptfs_dentry,
1473 int validate_header_size)
1479 ecryptfs_set_default_sizes(crypt_stat);
1480 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1481 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1482 offset = ECRYPTFS_FILE_SIZE_BYTES;
1483 rc = contains_ecryptfs_marker(page_virt + offset);
1488 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1489 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1492 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1495 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1496 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1497 "file version [%d] is supported by this "
1498 "version of eCryptfs\n",
1499 crypt_stat->file_version,
1500 ECRYPTFS_SUPPORTED_FILE_VERSION);
1504 offset += bytes_read;
1505 if (crypt_stat->file_version >= 1) {
1506 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
1507 &bytes_read, validate_header_size);
1509 ecryptfs_printk(KERN_WARNING, "Error reading header "
1510 "metadata; rc = [%d]\n", rc);
1512 offset += bytes_read;
1514 set_default_header_data(crypt_stat);
1515 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1522 * ecryptfs_read_xattr_region
1523 * @page_virt: The vitual address into which to read the xattr data
1524 * @ecryptfs_inode: The eCryptfs inode
1526 * Attempts to read the crypto metadata from the extended attribute
1527 * region of the lower file.
1529 * Returns zero on success; non-zero on error
1531 int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
1533 struct dentry *lower_dentry =
1534 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
1538 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1539 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
1541 if (unlikely(ecryptfs_verbosity > 0))
1542 printk(KERN_INFO "Error attempting to read the [%s] "
1543 "xattr from the lower file; return value = "
1544 "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
1552 int ecryptfs_read_and_validate_xattr_region(char *page_virt,
1553 struct dentry *ecryptfs_dentry)
1557 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
1560 if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
1561 printk(KERN_WARNING "Valid data found in [%s] xattr, but "
1562 "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
1570 * ecryptfs_read_metadata
1572 * Common entry point for reading file metadata. From here, we could
1573 * retrieve the header information from the header region of the file,
1574 * the xattr region of the file, or some other repostory that is
1575 * stored separately from the file itself. The current implementation
1576 * supports retrieving the metadata information from the file contents
1577 * and from the xattr region.
1579 * Returns zero if valid headers found and parsed; non-zero otherwise
1581 int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
1584 char *page_virt = NULL;
1585 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
1586 struct ecryptfs_crypt_stat *crypt_stat =
1587 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1588 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1589 &ecryptfs_superblock_to_private(
1590 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1592 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1594 /* Read the first page from the underlying file */
1595 page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
1598 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
1602 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1605 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1607 ECRYPTFS_VALIDATE_HEADER_SIZE);
1609 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
1611 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1612 "file header region or xattr region\n");
1616 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1618 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1620 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1621 "file xattr region either\n");
1624 if (crypt_stat->mount_crypt_stat->flags
1625 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1626 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1628 printk(KERN_WARNING "Attempt to access file with "
1629 "crypto metadata only in the extended attribute "
1630 "region, but eCryptfs was mounted without "
1631 "xattr support enabled. eCryptfs will not treat "
1632 "this like an encrypted file.\n");
1638 memset(page_virt, 0, PAGE_CACHE_SIZE);
1639 kmem_cache_free(ecryptfs_header_cache_1, page_virt);
1645 * ecryptfs_encrypt_filename - encrypt filename
1647 * CBC-encrypts the filename. We do not want to encrypt the same
1648 * filename with the same key and IV, which may happen with hard
1649 * links, so we prepend random bits to each filename.
1651 * Returns zero on success; non-zero otherwise
1654 ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1655 struct ecryptfs_crypt_stat *crypt_stat,
1656 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1660 filename->encrypted_filename = NULL;
1661 filename->encrypted_filename_size = 0;
1662 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
1663 || (mount_crypt_stat && (mount_crypt_stat->flags
1664 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
1666 size_t remaining_bytes;
1668 rc = ecryptfs_write_tag_70_packet(
1670 &filename->encrypted_filename_size,
1671 mount_crypt_stat, NULL,
1672 filename->filename_size);
1674 printk(KERN_ERR "%s: Error attempting to get packet "
1675 "size for tag 72; rc = [%d]\n", __func__,
1677 filename->encrypted_filename_size = 0;
1680 filename->encrypted_filename =
1681 kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1682 if (!filename->encrypted_filename) {
1683 printk(KERN_ERR "%s: Out of memory whilst attempting "
1684 "to kmalloc [%zd] bytes\n", __func__,
1685 filename->encrypted_filename_size);
1689 remaining_bytes = filename->encrypted_filename_size;
1690 rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
1695 filename->filename_size);
1697 printk(KERN_ERR "%s: Error attempting to generate "
1698 "tag 70 packet; rc = [%d]\n", __func__,
1700 kfree(filename->encrypted_filename);
1701 filename->encrypted_filename = NULL;
1702 filename->encrypted_filename_size = 0;
1705 filename->encrypted_filename_size = packet_size;
1707 printk(KERN_ERR "%s: No support for requested filename "
1708 "encryption method in this release\n", __func__);
1716 static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1717 const char *name, size_t name_size)
1721 (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
1722 if (!(*copied_name)) {
1726 memcpy((void *)(*copied_name), (void *)name, name_size);
1727 (*copied_name)[(name_size)] = '\0'; /* Only for convenience
1728 * in printing out the
1731 (*copied_name_size) = name_size;
1737 * ecryptfs_process_key_cipher - Perform key cipher initialization.
1738 * @key_tfm: Crypto context for key material, set by this function
1739 * @cipher_name: Name of the cipher
1740 * @key_size: Size of the key in bytes
1742 * Returns zero on success. Any crypto_tfm structs allocated here
1743 * should be released by other functions, such as on a superblock put
1744 * event, regardless of whether this function succeeds for fails.
1747 ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1748 char *cipher_name, size_t *key_size)
1750 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
1751 char *full_alg_name = NULL;
1755 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
1757 printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
1758 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
1761 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1765 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1766 if (IS_ERR(*key_tfm)) {
1767 rc = PTR_ERR(*key_tfm);
1768 printk(KERN_ERR "Unable to allocate crypto cipher with name "
1769 "[%s]; rc = [%d]\n", full_alg_name, rc);
1772 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1773 if (*key_size == 0) {
1774 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1776 *key_size = alg->max_keysize;
1778 get_random_bytes(dummy_key, *key_size);
1779 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
1781 printk(KERN_ERR "Error attempting to set key of size [%zd] for "
1782 "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name,
1788 kfree(full_alg_name);
1792 struct kmem_cache *ecryptfs_key_tfm_cache;
1793 static struct list_head key_tfm_list;
1794 struct mutex key_tfm_list_mutex;
1796 int ecryptfs_init_crypto(void)
1798 mutex_init(&key_tfm_list_mutex);
1799 INIT_LIST_HEAD(&key_tfm_list);
1804 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1806 * Called only at module unload time
1808 int ecryptfs_destroy_crypto(void)
1810 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1812 mutex_lock(&key_tfm_list_mutex);
1813 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1815 list_del(&key_tfm->key_tfm_list);
1816 if (key_tfm->key_tfm)
1817 crypto_free_blkcipher(key_tfm->key_tfm);
1818 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1820 mutex_unlock(&key_tfm_list_mutex);
1825 ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1828 struct ecryptfs_key_tfm *tmp_tfm;
1831 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1833 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1834 if (key_tfm != NULL)
1835 (*key_tfm) = tmp_tfm;
1838 printk(KERN_ERR "Error attempting to allocate from "
1839 "ecryptfs_key_tfm_cache\n");
1842 mutex_init(&tmp_tfm->key_tfm_mutex);
1843 strncpy(tmp_tfm->cipher_name, cipher_name,
1844 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
1845 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
1846 tmp_tfm->key_size = key_size;
1847 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1848 tmp_tfm->cipher_name,
1849 &tmp_tfm->key_size);
1851 printk(KERN_ERR "Error attempting to initialize key TFM "
1852 "cipher with name = [%s]; rc = [%d]\n",
1853 tmp_tfm->cipher_name, rc);
1854 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1855 if (key_tfm != NULL)
1859 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
1865 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1866 * @cipher_name: the name of the cipher to search for
1867 * @key_tfm: set to corresponding tfm if found
1869 * Searches for cached key_tfm matching @cipher_name
1870 * Must be called with &key_tfm_list_mutex held
1871 * Returns 1 if found, with @key_tfm set
1872 * Returns 0 if not found, with @key_tfm set to NULL
1874 int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1876 struct ecryptfs_key_tfm *tmp_key_tfm;
1878 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1880 list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1881 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1883 (*key_tfm) = tmp_key_tfm;
1893 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1895 * @tfm: set to cached tfm found, or new tfm created
1896 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1897 * @cipher_name: the name of the cipher to search for and/or add
1899 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1900 * Searches for cached item first, and creates new if not found.
1901 * Returns 0 on success, non-zero if adding new cipher failed
1903 int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1904 struct mutex **tfm_mutex,
1907 struct ecryptfs_key_tfm *key_tfm;
1911 (*tfm_mutex) = NULL;
1913 mutex_lock(&key_tfm_list_mutex);
1914 if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1915 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1917 printk(KERN_ERR "Error adding new key_tfm to list; "
1922 (*tfm) = key_tfm->key_tfm;
1923 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1925 mutex_unlock(&key_tfm_list_mutex);
1929 /* 64 characters forming a 6-bit target field */
1930 static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1933 "klmnopqrstuvwxyz");
1935 /* We could either offset on every reverse map or just pad some 0x00's
1936 * at the front here */
1937 static const unsigned char filename_rev_map[] = {
1938 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1939 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1940 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1941 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1942 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1943 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1944 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1945 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1946 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1947 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1948 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1949 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1950 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1951 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1952 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
1957 * ecryptfs_encode_for_filename
1958 * @dst: Destination location for encoded filename
1959 * @dst_size: Size of the encoded filename in bytes
1960 * @src: Source location for the filename to encode
1961 * @src_size: Size of the source in bytes
1963 void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
1964 unsigned char *src, size_t src_size)
1967 size_t block_num = 0;
1968 size_t dst_offset = 0;
1969 unsigned char last_block[3];
1971 if (src_size == 0) {
1975 num_blocks = (src_size / 3);
1976 if ((src_size % 3) == 0) {
1977 memcpy(last_block, (&src[src_size - 3]), 3);
1980 last_block[2] = 0x00;
1981 switch (src_size % 3) {
1983 last_block[0] = src[src_size - 1];
1984 last_block[1] = 0x00;
1987 last_block[0] = src[src_size - 2];
1988 last_block[1] = src[src_size - 1];
1991 (*dst_size) = (num_blocks * 4);
1994 while (block_num < num_blocks) {
1995 unsigned char *src_block;
1996 unsigned char dst_block[4];
1998 if (block_num == (num_blocks - 1))
1999 src_block = last_block;
2001 src_block = &src[block_num * 3];
2002 dst_block[0] = ((src_block[0] >> 2) & 0x3F);
2003 dst_block[1] = (((src_block[0] << 4) & 0x30)
2004 | ((src_block[1] >> 4) & 0x0F));
2005 dst_block[2] = (((src_block[1] << 2) & 0x3C)
2006 | ((src_block[2] >> 6) & 0x03));
2007 dst_block[3] = (src_block[2] & 0x3F);
2008 dst[dst_offset++] = portable_filename_chars[dst_block[0]];
2009 dst[dst_offset++] = portable_filename_chars[dst_block[1]];
2010 dst[dst_offset++] = portable_filename_chars[dst_block[2]];
2011 dst[dst_offset++] = portable_filename_chars[dst_block[3]];
2019 * ecryptfs_decode_from_filename
2020 * @dst: If NULL, this function only sets @dst_size and returns. If
2021 * non-NULL, this function decodes the encoded octets in @src
2022 * into the memory that @dst points to.
2023 * @dst_size: Set to the size of the decoded string.
2024 * @src: The encoded set of octets to decode.
2025 * @src_size: The size of the encoded set of octets to decode.
2028 ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
2029 const unsigned char *src, size_t src_size)
2031 u8 current_bit_offset = 0;
2032 size_t src_byte_offset = 0;
2033 size_t dst_byte_offset = 0;
2036 /* Not exact; conservatively long. Every block of 4
2037 * encoded characters decodes into a block of 3
2038 * decoded characters. This segment of code provides
2039 * the caller with the maximum amount of allocated
2040 * space that @dst will need to point to in a
2041 * subsequent call. */
2042 (*dst_size) = (((src_size + 1) * 3) / 4);
2045 while (src_byte_offset < src_size) {
2046 unsigned char src_byte =
2047 filename_rev_map[(int)src[src_byte_offset]];
2049 switch (current_bit_offset) {
2051 dst[dst_byte_offset] = (src_byte << 2);
2052 current_bit_offset = 6;
2055 dst[dst_byte_offset++] |= (src_byte >> 4);
2056 dst[dst_byte_offset] = ((src_byte & 0xF)
2058 current_bit_offset = 4;
2061 dst[dst_byte_offset++] |= (src_byte >> 2);
2062 dst[dst_byte_offset] = (src_byte << 6);
2063 current_bit_offset = 2;
2066 dst[dst_byte_offset++] |= (src_byte);
2067 dst[dst_byte_offset] = 0;
2068 current_bit_offset = 0;
2073 (*dst_size) = dst_byte_offset;
2079 * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
2080 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
2081 * @name: The plaintext name
2082 * @length: The length of the plaintext
2083 * @encoded_name: The encypted name
2085 * Encrypts and encodes a filename into something that constitutes a
2086 * valid filename for a filesystem, with printable characters.
2088 * We assume that we have a properly initialized crypto context,
2089 * pointed to by crypt_stat->tfm.
2091 * Returns zero on success; non-zero on otherwise
2093 int ecryptfs_encrypt_and_encode_filename(
2094 char **encoded_name,
2095 size_t *encoded_name_size,
2096 struct ecryptfs_crypt_stat *crypt_stat,
2097 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2098 const char *name, size_t name_size)
2100 size_t encoded_name_no_prefix_size;
2103 (*encoded_name) = NULL;
2104 (*encoded_name_size) = 0;
2105 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
2106 || (mount_crypt_stat && (mount_crypt_stat->flags
2107 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) {
2108 struct ecryptfs_filename *filename;
2110 filename = kzalloc(sizeof(*filename), GFP_KERNEL);
2112 printk(KERN_ERR "%s: Out of memory whilst attempting "
2113 "to kzalloc [%zd] bytes\n", __func__,
2118 filename->filename = (char *)name;
2119 filename->filename_size = name_size;
2120 rc = ecryptfs_encrypt_filename(filename, crypt_stat,
2123 printk(KERN_ERR "%s: Error attempting to encrypt "
2124 "filename; rc = [%d]\n", __func__, rc);
2128 ecryptfs_encode_for_filename(
2129 NULL, &encoded_name_no_prefix_size,
2130 filename->encrypted_filename,
2131 filename->encrypted_filename_size);
2132 if ((crypt_stat && (crypt_stat->flags
2133 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2134 || (mount_crypt_stat
2135 && (mount_crypt_stat->flags
2136 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)))
2137 (*encoded_name_size) =
2138 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2139 + encoded_name_no_prefix_size);
2141 (*encoded_name_size) =
2142 (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2143 + encoded_name_no_prefix_size);
2144 (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
2145 if (!(*encoded_name)) {
2146 printk(KERN_ERR "%s: Out of memory whilst attempting "
2147 "to kzalloc [%zd] bytes\n", __func__,
2148 (*encoded_name_size));
2150 kfree(filename->encrypted_filename);
2154 if ((crypt_stat && (crypt_stat->flags
2155 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2156 || (mount_crypt_stat
2157 && (mount_crypt_stat->flags
2158 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
2159 memcpy((*encoded_name),
2160 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2161 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
2162 ecryptfs_encode_for_filename(
2164 + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
2165 &encoded_name_no_prefix_size,
2166 filename->encrypted_filename,
2167 filename->encrypted_filename_size);
2168 (*encoded_name_size) =
2169 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2170 + encoded_name_no_prefix_size);
2171 (*encoded_name)[(*encoded_name_size)] = '\0';
2172 (*encoded_name_size)++;
2177 printk(KERN_ERR "%s: Error attempting to encode "
2178 "encrypted filename; rc = [%d]\n", __func__,
2180 kfree((*encoded_name));
2181 (*encoded_name) = NULL;
2182 (*encoded_name_size) = 0;
2184 kfree(filename->encrypted_filename);
2187 rc = ecryptfs_copy_filename(encoded_name,
2196 * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
2197 * @plaintext_name: The plaintext name
2198 * @plaintext_name_size: The plaintext name size
2199 * @ecryptfs_dir_dentry: eCryptfs directory dentry
2200 * @name: The filename in cipher text
2201 * @name_size: The cipher text name size
2203 * Decrypts and decodes the filename.
2205 * Returns zero on error; non-zero otherwise
2207 int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
2208 size_t *plaintext_name_size,
2209 struct dentry *ecryptfs_dir_dentry,
2210 const char *name, size_t name_size)
2212 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2213 &ecryptfs_superblock_to_private(
2214 ecryptfs_dir_dentry->d_sb)->mount_crypt_stat;
2216 size_t decoded_name_size;
2220 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
2221 && !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
2222 && (name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
2223 && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2224 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
2225 const char *orig_name = name;
2226 size_t orig_name_size = name_size;
2228 name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2229 name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2230 ecryptfs_decode_from_filename(NULL, &decoded_name_size,
2232 decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
2233 if (!decoded_name) {
2234 printk(KERN_ERR "%s: Out of memory whilst attempting "
2235 "to kmalloc [%zd] bytes\n", __func__,
2240 ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
2242 rc = ecryptfs_parse_tag_70_packet(plaintext_name,
2243 plaintext_name_size,
2249 printk(KERN_INFO "%s: Could not parse tag 70 packet "
2250 "from filename; copying through filename "
2251 "as-is\n", __func__);
2252 rc = ecryptfs_copy_filename(plaintext_name,
2253 plaintext_name_size,
2254 orig_name, orig_name_size);
2258 rc = ecryptfs_copy_filename(plaintext_name,
2259 plaintext_name_size,
2264 kfree(decoded_name);