2 * eCryptfs: Linux filesystem encryption layer
4 * Copyright (C) 1997-2004 Erez Zadok
5 * Copyright (C) 2001-2004 Stony Brook University
6 * Copyright (C) 2004-2007 International Business Machines Corp.
7 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
8 * Michael C. Thompson <mcthomps@us.ibm.com>
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of the
13 * License, or (at your option) any later version.
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
27 #include <linux/mount.h>
28 #include <linux/pagemap.h>
29 #include <linux/random.h>
30 #include <linux/compiler.h>
31 #include <linux/key.h>
32 #include <linux/namei.h>
33 #include <linux/crypto.h>
34 #include <linux/file.h>
35 #include <linux/scatterlist.h>
36 #include <linux/slab.h>
37 #include <asm/unaligned.h>
38 #include "ecryptfs_kernel.h"
43 static int crypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
44 struct page *dst_page, struct page *src_page,
45 int offset, int size, unsigned char *iv, int op);
49 * @dst: Buffer to take hex character representation of contents of
50 * src; must be at least of size (src_size * 2)
51 * @src: Buffer to be converted to a hex string respresentation
52 * @src_size: number of bytes to convert
54 void ecryptfs_to_hex(char *dst, char *src, size_t src_size)
58 for (x = 0; x < src_size; x++)
59 sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]);
64 * @dst: Buffer to take the bytes from src hex; must be at least of
66 * @src: Buffer to be converted from a hex string respresentation to raw value
67 * @dst_size: size of dst buffer, or number of hex characters pairs to convert
69 void ecryptfs_from_hex(char *dst, char *src, int dst_size)
74 for (x = 0; x < dst_size; x++) {
76 tmp[1] = src[x * 2 + 1];
77 dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
82 * ecryptfs_calculate_md5 - calculates the md5 of @src
83 * @dst: Pointer to 16 bytes of allocated memory
84 * @crypt_stat: Pointer to crypt_stat struct for the current inode
85 * @src: Data to be md5'd
86 * @len: Length of @src
88 * Uses the allocated crypto context that crypt_stat references to
89 * generate the MD5 sum of the contents of src.
91 static int ecryptfs_calculate_md5(char *dst,
92 struct ecryptfs_crypt_stat *crypt_stat,
95 struct scatterlist sg;
96 struct hash_desc desc = {
97 .tfm = crypt_stat->hash_tfm,
98 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
102 mutex_lock(&crypt_stat->cs_hash_tfm_mutex);
103 sg_init_one(&sg, (u8 *)src, len);
105 desc.tfm = crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH, 0,
107 if (IS_ERR(desc.tfm)) {
108 rc = PTR_ERR(desc.tfm);
109 ecryptfs_printk(KERN_ERR, "Error attempting to "
110 "allocate crypto context; rc = [%d]\n",
114 crypt_stat->hash_tfm = desc.tfm;
116 rc = crypto_hash_init(&desc);
119 "%s: Error initializing crypto hash; rc = [%d]\n",
123 rc = crypto_hash_update(&desc, &sg, len);
126 "%s: Error updating crypto hash; rc = [%d]\n",
130 rc = crypto_hash_final(&desc, dst);
133 "%s: Error finalizing crypto hash; rc = [%d]\n",
138 mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
142 static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
144 char *chaining_modifier)
146 int cipher_name_len = strlen(cipher_name);
147 int chaining_modifier_len = strlen(chaining_modifier);
148 int algified_name_len;
151 algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
152 (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
153 if (!(*algified_name)) {
157 snprintf((*algified_name), algified_name_len, "%s(%s)",
158 chaining_modifier, cipher_name);
166 * @iv: destination for the derived iv vale
167 * @crypt_stat: Pointer to crypt_stat struct for the current inode
168 * @offset: Offset of the extent whose IV we are to derive
170 * Generate the initialization vector from the given root IV and page
173 * Returns zero on success; non-zero on error.
175 int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
179 char dst[MD5_DIGEST_SIZE];
180 char src[ECRYPTFS_MAX_IV_BYTES + 16];
182 if (unlikely(ecryptfs_verbosity > 0)) {
183 ecryptfs_printk(KERN_DEBUG, "root iv:\n");
184 ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
186 /* TODO: It is probably secure to just cast the least
187 * significant bits of the root IV into an unsigned long and
188 * add the offset to that rather than go through all this
189 * hashing business. -Halcrow */
190 memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
191 memset((src + crypt_stat->iv_bytes), 0, 16);
192 snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
193 if (unlikely(ecryptfs_verbosity > 0)) {
194 ecryptfs_printk(KERN_DEBUG, "source:\n");
195 ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
197 rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
198 (crypt_stat->iv_bytes + 16));
200 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
201 "MD5 while generating IV for a page\n");
204 memcpy(iv, dst, crypt_stat->iv_bytes);
205 if (unlikely(ecryptfs_verbosity > 0)) {
206 ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
207 ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
214 * ecryptfs_init_crypt_stat
215 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
217 * Initialize the crypt_stat structure.
220 ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
222 memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
223 INIT_LIST_HEAD(&crypt_stat->keysig_list);
224 mutex_init(&crypt_stat->keysig_list_mutex);
225 mutex_init(&crypt_stat->cs_mutex);
226 mutex_init(&crypt_stat->cs_tfm_mutex);
227 mutex_init(&crypt_stat->cs_hash_tfm_mutex);
228 crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
232 * ecryptfs_destroy_crypt_stat
233 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
235 * Releases all memory associated with a crypt_stat struct.
237 void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
239 struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
242 crypto_free_ablkcipher(crypt_stat->tfm);
243 if (crypt_stat->hash_tfm)
244 crypto_free_hash(crypt_stat->hash_tfm);
245 list_for_each_entry_safe(key_sig, key_sig_tmp,
246 &crypt_stat->keysig_list, crypt_stat_list) {
247 list_del(&key_sig->crypt_stat_list);
248 kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
250 memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
253 void ecryptfs_destroy_mount_crypt_stat(
254 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
256 struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
258 if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
260 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
261 list_for_each_entry_safe(auth_tok, auth_tok_tmp,
262 &mount_crypt_stat->global_auth_tok_list,
263 mount_crypt_stat_list) {
264 list_del(&auth_tok->mount_crypt_stat_list);
265 if (auth_tok->global_auth_tok_key
266 && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
267 key_put(auth_tok->global_auth_tok_key);
268 kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
270 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
271 memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
275 * virt_to_scatterlist
276 * @addr: Virtual address
277 * @size: Size of data; should be an even multiple of the block size
278 * @sg: Pointer to scatterlist array; set to NULL to obtain only
279 * the number of scatterlist structs required in array
280 * @sg_size: Max array size
282 * Fills in a scatterlist array with page references for a passed
285 * Returns the number of scatterlist structs in array used
287 int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
293 int remainder_of_page;
295 sg_init_table(sg, sg_size);
297 while (size > 0 && i < sg_size) {
298 pg = virt_to_page(addr);
299 offset = offset_in_page(addr);
300 sg_set_page(&sg[i], pg, 0, offset);
301 remainder_of_page = PAGE_CACHE_SIZE - offset;
302 if (size >= remainder_of_page) {
303 sg[i].length = remainder_of_page;
304 addr += remainder_of_page;
305 size -= remainder_of_page;
318 struct extent_crypt_result {
319 struct completion completion;
323 static void extent_crypt_complete(struct crypto_async_request *req, int rc)
325 struct extent_crypt_result *ecr = req->data;
327 if (rc == -EINPROGRESS)
331 complete(&ecr->completion);
336 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
337 * @dest_sg: Destination of the data after performing the crypto operation
338 * @src_sg: Data to be encrypted or decrypted
339 * @size: Length of data
341 * @op: ENCRYPT or DECRYPT to indicate the desired operation
343 * Returns the number of bytes encrypted or decrypted; negative value on error
345 static int crypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
346 struct scatterlist *dest_sg,
347 struct scatterlist *src_sg, int size,
348 unsigned char *iv, int op)
350 struct ablkcipher_request *req = NULL;
351 struct extent_crypt_result ecr;
354 BUG_ON(!crypt_stat || !crypt_stat->tfm
355 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
356 if (unlikely(ecryptfs_verbosity > 0)) {
357 ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
358 crypt_stat->key_size);
359 ecryptfs_dump_hex(crypt_stat->key,
360 crypt_stat->key_size);
363 init_completion(&ecr.completion);
365 mutex_lock(&crypt_stat->cs_tfm_mutex);
366 req = ablkcipher_request_alloc(crypt_stat->tfm, GFP_NOFS);
368 mutex_unlock(&crypt_stat->cs_tfm_mutex);
373 ablkcipher_request_set_callback(req,
374 CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
375 extent_crypt_complete, &ecr);
376 /* Consider doing this once, when the file is opened */
377 if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
378 rc = crypto_ablkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
379 crypt_stat->key_size);
381 ecryptfs_printk(KERN_ERR,
382 "Error setting key; rc = [%d]\n",
384 mutex_unlock(&crypt_stat->cs_tfm_mutex);
388 crypt_stat->flags |= ECRYPTFS_KEY_SET;
390 mutex_unlock(&crypt_stat->cs_tfm_mutex);
391 ablkcipher_request_set_crypt(req, src_sg, dest_sg, size, iv);
392 rc = op == ENCRYPT ? crypto_ablkcipher_encrypt(req) :
393 crypto_ablkcipher_decrypt(req);
394 if (rc == -EINPROGRESS || rc == -EBUSY) {
395 struct extent_crypt_result *ecr = req->base.data;
397 wait_for_completion(&ecr->completion);
399 INIT_COMPLETION(ecr->completion);
402 ablkcipher_request_free(req);
407 * lower_offset_for_page
409 * Convert an eCryptfs page index into a lower byte offset
411 static loff_t lower_offset_for_page(struct ecryptfs_crypt_stat *crypt_stat,
414 return ecryptfs_lower_header_size(crypt_stat) +
415 (page->index << PAGE_CACHE_SHIFT);
419 * ecryptfs_encrypt_extent
420 * @enc_extent_page: Allocated page into which to encrypt the data in
422 * @crypt_stat: crypt_stat containing cryptographic context for the
423 * encryption operation
424 * @page: Page containing plaintext data extent to encrypt
425 * @extent_offset: Page extent offset for use in generating IV
427 * Encrypts one extent of data.
429 * Return zero on success; non-zero otherwise
431 static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
432 struct ecryptfs_crypt_stat *crypt_stat,
434 unsigned long extent_offset)
437 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
440 extent_base = (((loff_t)page->index)
441 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
442 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
443 (extent_base + extent_offset));
445 ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
446 "extent [0x%.16llx]; rc = [%d]\n",
447 (unsigned long long)(extent_base + extent_offset), rc);
450 rc = crypt_page_offset(crypt_stat, enc_extent_page, page,
451 (extent_offset * crypt_stat->extent_size),
452 crypt_stat->extent_size, extent_iv, ENCRYPT);
454 printk(KERN_ERR "%s: Error attempting to encrypt page with "
455 "page->index = [%ld], extent_offset = [%ld]; "
456 "rc = [%d]\n", __func__, page->index, extent_offset,
466 * ecryptfs_encrypt_page
467 * @page: Page mapped from the eCryptfs inode for the file; contains
468 * decrypted content that needs to be encrypted (to a temporary
469 * page; not in place) and written out to the lower file
471 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
472 * that eCryptfs pages may straddle the lower pages -- for instance,
473 * if the file was created on a machine with an 8K page size
474 * (resulting in an 8K header), and then the file is copied onto a
475 * host with a 32K page size, then when reading page 0 of the eCryptfs
476 * file, 24K of page 0 of the lower file will be read and decrypted,
477 * and then 8K of page 1 of the lower file will be read and decrypted.
479 * Returns zero on success; negative on error
481 int ecryptfs_encrypt_page(struct page *page)
483 struct inode *ecryptfs_inode;
484 struct ecryptfs_crypt_stat *crypt_stat;
485 char *enc_extent_virt;
486 struct page *enc_extent_page = NULL;
487 loff_t extent_offset;
491 ecryptfs_inode = page->mapping->host;
493 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
494 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
495 enc_extent_page = alloc_page(GFP_USER);
496 if (!enc_extent_page) {
498 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
499 "encrypted extent\n");
503 for (extent_offset = 0;
504 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
506 rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
509 printk(KERN_ERR "%s: Error encrypting extent; "
510 "rc = [%d]\n", __func__, rc);
515 lower_offset = lower_offset_for_page(crypt_stat, page);
516 enc_extent_virt = kmap(enc_extent_page);
517 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset,
519 kunmap(enc_extent_page);
521 ecryptfs_printk(KERN_ERR,
522 "Error attempting to write lower page; rc = [%d]\n",
528 if (enc_extent_page) {
529 __free_page(enc_extent_page);
534 static int ecryptfs_decrypt_extent(struct page *page,
535 struct ecryptfs_crypt_stat *crypt_stat,
536 struct page *enc_extent_page,
537 unsigned long extent_offset)
540 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
543 extent_base = (((loff_t)page->index)
544 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
545 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
546 (extent_base + extent_offset));
548 ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
549 "extent [0x%.16llx]; rc = [%d]\n",
550 (unsigned long long)(extent_base + extent_offset), rc);
553 rc = crypt_page_offset(crypt_stat, page, enc_extent_page,
554 (extent_offset * crypt_stat->extent_size),
555 crypt_stat->extent_size, extent_iv, DECRYPT);
557 printk(KERN_ERR "%s: Error attempting to decrypt to page with "
558 "page->index = [%ld], extent_offset = [%ld]; "
559 "rc = [%d]\n", __func__, page->index, extent_offset,
569 * ecryptfs_decrypt_page
570 * @page: Page mapped from the eCryptfs inode for the file; data read
571 * and decrypted from the lower file will be written into this
574 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
575 * that eCryptfs pages may straddle the lower pages -- for instance,
576 * if the file was created on a machine with an 8K page size
577 * (resulting in an 8K header), and then the file is copied onto a
578 * host with a 32K page size, then when reading page 0 of the eCryptfs
579 * file, 24K of page 0 of the lower file will be read and decrypted,
580 * and then 8K of page 1 of the lower file will be read and decrypted.
582 * Returns zero on success; negative on error
584 int ecryptfs_decrypt_page(struct page *page)
586 struct inode *ecryptfs_inode;
587 struct ecryptfs_crypt_stat *crypt_stat;
589 unsigned long extent_offset;
593 ecryptfs_inode = page->mapping->host;
595 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
596 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
598 lower_offset = lower_offset_for_page(crypt_stat, page);
599 page_virt = kmap(page);
600 rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_CACHE_SIZE,
604 ecryptfs_printk(KERN_ERR,
605 "Error attempting to read lower page; rc = [%d]\n",
610 for (extent_offset = 0;
611 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
613 rc = ecryptfs_decrypt_extent(page, crypt_stat, page,
616 printk(KERN_ERR "%s: Error encrypting extent; "
617 "rc = [%d]\n", __func__, rc);
627 * @crypt_stat: The cryptographic context
628 * @dst_page: The page to write the result into
629 * @src_page: The page to read from
630 * @offset: The byte offset into the dst_page and src_page
631 * @size: The number of bytes of data
632 * @iv: The initialization vector to use for the crypto operation
633 * @op: ENCRYPT or DECRYPT to indicate the desired operation
635 * Returns the number of bytes encrypted or decrypted
637 static int crypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
638 struct page *dst_page, struct page *src_page,
639 int offset, int size, unsigned char *iv, int op)
641 struct scatterlist src_sg, dst_sg;
643 sg_init_table(&src_sg, 1);
644 sg_init_table(&dst_sg, 1);
646 sg_set_page(&src_sg, src_page, size, offset);
647 sg_set_page(&dst_sg, dst_page, size, offset);
649 return crypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv, op);
652 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
655 * ecryptfs_init_crypt_ctx
656 * @crypt_stat: Uninitialized crypt stats structure
658 * Initialize the crypto context.
660 * TODO: Performance: Keep a cache of initialized cipher contexts;
661 * only init if needed
663 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
668 if (!crypt_stat->cipher) {
669 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
672 ecryptfs_printk(KERN_DEBUG,
673 "Initializing cipher [%s]; strlen = [%d]; "
674 "key_size_bits = [%zd]\n",
675 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
676 crypt_stat->key_size << 3);
677 if (crypt_stat->tfm) {
681 mutex_lock(&crypt_stat->cs_tfm_mutex);
682 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
683 crypt_stat->cipher, "cbc");
686 crypt_stat->tfm = crypto_alloc_ablkcipher(full_alg_name, 0, 0);
687 kfree(full_alg_name);
688 if (IS_ERR(crypt_stat->tfm)) {
689 rc = PTR_ERR(crypt_stat->tfm);
690 crypt_stat->tfm = NULL;
691 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
692 "Error initializing cipher [%s]\n",
696 crypto_ablkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
699 mutex_unlock(&crypt_stat->cs_tfm_mutex);
704 static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
708 crypt_stat->extent_mask = 0xFFFFFFFF;
709 crypt_stat->extent_shift = 0;
710 if (crypt_stat->extent_size == 0)
712 extent_size_tmp = crypt_stat->extent_size;
713 while ((extent_size_tmp & 0x01) == 0) {
714 extent_size_tmp >>= 1;
715 crypt_stat->extent_mask <<= 1;
716 crypt_stat->extent_shift++;
720 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
722 /* Default values; may be overwritten as we are parsing the
724 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
725 set_extent_mask_and_shift(crypt_stat);
726 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
727 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
728 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
730 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
731 crypt_stat->metadata_size =
732 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
734 crypt_stat->metadata_size = PAGE_CACHE_SIZE;
739 * ecryptfs_compute_root_iv
742 * On error, sets the root IV to all 0's.
744 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
747 char dst[MD5_DIGEST_SIZE];
749 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
750 BUG_ON(crypt_stat->iv_bytes <= 0);
751 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
753 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
754 "cannot generate root IV\n");
757 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
758 crypt_stat->key_size);
760 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
761 "MD5 while generating root IV\n");
764 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
767 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
768 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
773 static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
775 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
776 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
777 ecryptfs_compute_root_iv(crypt_stat);
778 if (unlikely(ecryptfs_verbosity > 0)) {
779 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
780 ecryptfs_dump_hex(crypt_stat->key,
781 crypt_stat->key_size);
786 * ecryptfs_copy_mount_wide_flags_to_inode_flags
787 * @crypt_stat: The inode's cryptographic context
788 * @mount_crypt_stat: The mount point's cryptographic context
790 * This function propagates the mount-wide flags to individual inode
793 static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
794 struct ecryptfs_crypt_stat *crypt_stat,
795 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
797 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
798 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
799 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
800 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
801 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
802 crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
803 if (mount_crypt_stat->flags
804 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
805 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
806 else if (mount_crypt_stat->flags
807 & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
808 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
812 static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
813 struct ecryptfs_crypt_stat *crypt_stat,
814 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
816 struct ecryptfs_global_auth_tok *global_auth_tok;
819 mutex_lock(&crypt_stat->keysig_list_mutex);
820 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
822 list_for_each_entry(global_auth_tok,
823 &mount_crypt_stat->global_auth_tok_list,
824 mount_crypt_stat_list) {
825 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
827 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
829 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
835 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
836 mutex_unlock(&crypt_stat->keysig_list_mutex);
841 * ecryptfs_set_default_crypt_stat_vals
842 * @crypt_stat: The inode's cryptographic context
843 * @mount_crypt_stat: The mount point's cryptographic context
845 * Default values in the event that policy does not override them.
847 static void ecryptfs_set_default_crypt_stat_vals(
848 struct ecryptfs_crypt_stat *crypt_stat,
849 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
851 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
853 ecryptfs_set_default_sizes(crypt_stat);
854 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
855 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
856 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
857 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
858 crypt_stat->mount_crypt_stat = mount_crypt_stat;
862 * ecryptfs_new_file_context
863 * @ecryptfs_inode: The eCryptfs inode
865 * If the crypto context for the file has not yet been established,
866 * this is where we do that. Establishing a new crypto context
867 * involves the following decisions:
868 * - What cipher to use?
869 * - What set of authentication tokens to use?
870 * Here we just worry about getting enough information into the
871 * authentication tokens so that we know that they are available.
872 * We associate the available authentication tokens with the new file
873 * via the set of signatures in the crypt_stat struct. Later, when
874 * the headers are actually written out, we may again defer to
875 * userspace to perform the encryption of the session key; for the
876 * foreseeable future, this will be the case with public key packets.
878 * Returns zero on success; non-zero otherwise
880 int ecryptfs_new_file_context(struct inode *ecryptfs_inode)
882 struct ecryptfs_crypt_stat *crypt_stat =
883 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
884 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
885 &ecryptfs_superblock_to_private(
886 ecryptfs_inode->i_sb)->mount_crypt_stat;
890 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
891 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
892 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
894 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
897 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
898 "to the inode key sigs; rc = [%d]\n", rc);
902 strlen(mount_crypt_stat->global_default_cipher_name);
903 memcpy(crypt_stat->cipher,
904 mount_crypt_stat->global_default_cipher_name,
906 crypt_stat->cipher[cipher_name_len] = '\0';
907 crypt_stat->key_size =
908 mount_crypt_stat->global_default_cipher_key_size;
909 ecryptfs_generate_new_key(crypt_stat);
910 rc = ecryptfs_init_crypt_ctx(crypt_stat);
912 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
913 "context for cipher [%s]: rc = [%d]\n",
914 crypt_stat->cipher, rc);
920 * ecryptfs_validate_marker - check for the ecryptfs marker
921 * @data: The data block in which to check
923 * Returns zero if marker found; -EINVAL if not found
925 static int ecryptfs_validate_marker(char *data)
929 m_1 = get_unaligned_be32(data);
930 m_2 = get_unaligned_be32(data + 4);
931 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
933 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
934 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
935 MAGIC_ECRYPTFS_MARKER);
936 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
937 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
941 struct ecryptfs_flag_map_elem {
946 /* Add support for additional flags by adding elements here. */
947 static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
948 {0x00000001, ECRYPTFS_ENABLE_HMAC},
949 {0x00000002, ECRYPTFS_ENCRYPTED},
950 {0x00000004, ECRYPTFS_METADATA_IN_XATTR},
951 {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
955 * ecryptfs_process_flags
956 * @crypt_stat: The cryptographic context
957 * @page_virt: Source data to be parsed
958 * @bytes_read: Updated with the number of bytes read
960 * Returns zero on success; non-zero if the flag set is invalid
962 static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
963 char *page_virt, int *bytes_read)
969 flags = get_unaligned_be32(page_virt);
970 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
971 / sizeof(struct ecryptfs_flag_map_elem))); i++)
972 if (flags & ecryptfs_flag_map[i].file_flag) {
973 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
975 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
976 /* Version is in top 8 bits of the 32-bit flag vector */
977 crypt_stat->file_version = ((flags >> 24) & 0xFF);
983 * write_ecryptfs_marker
984 * @page_virt: The pointer to in a page to begin writing the marker
985 * @written: Number of bytes written
987 * Marker = 0x3c81b7f5
989 static void write_ecryptfs_marker(char *page_virt, size_t *written)
993 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
994 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
995 put_unaligned_be32(m_1, page_virt);
996 page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
997 put_unaligned_be32(m_2, page_virt);
998 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1001 void ecryptfs_write_crypt_stat_flags(char *page_virt,
1002 struct ecryptfs_crypt_stat *crypt_stat,
1008 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1009 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1010 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
1011 flags |= ecryptfs_flag_map[i].file_flag;
1012 /* Version is in top 8 bits of the 32-bit flag vector */
1013 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
1014 put_unaligned_be32(flags, page_virt);
1018 struct ecryptfs_cipher_code_str_map_elem {
1019 char cipher_str[16];
1023 /* Add support for additional ciphers by adding elements here. The
1024 * cipher_code is whatever OpenPGP applicatoins use to identify the
1025 * ciphers. List in order of probability. */
1026 static struct ecryptfs_cipher_code_str_map_elem
1027 ecryptfs_cipher_code_str_map[] = {
1028 {"aes",RFC2440_CIPHER_AES_128 },
1029 {"blowfish", RFC2440_CIPHER_BLOWFISH},
1030 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1031 {"cast5", RFC2440_CIPHER_CAST_5},
1032 {"twofish", RFC2440_CIPHER_TWOFISH},
1033 {"cast6", RFC2440_CIPHER_CAST_6},
1034 {"aes", RFC2440_CIPHER_AES_192},
1035 {"aes", RFC2440_CIPHER_AES_256}
1039 * ecryptfs_code_for_cipher_string
1040 * @cipher_name: The string alias for the cipher
1041 * @key_bytes: Length of key in bytes; used for AES code selection
1043 * Returns zero on no match, or the cipher code on match
1045 u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
1049 struct ecryptfs_cipher_code_str_map_elem *map =
1050 ecryptfs_cipher_code_str_map;
1052 if (strcmp(cipher_name, "aes") == 0) {
1053 switch (key_bytes) {
1055 code = RFC2440_CIPHER_AES_128;
1058 code = RFC2440_CIPHER_AES_192;
1061 code = RFC2440_CIPHER_AES_256;
1064 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1065 if (strcmp(cipher_name, map[i].cipher_str) == 0) {
1066 code = map[i].cipher_code;
1074 * ecryptfs_cipher_code_to_string
1075 * @str: Destination to write out the cipher name
1076 * @cipher_code: The code to convert to cipher name string
1078 * Returns zero on success
1080 int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
1086 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1087 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1088 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1089 if (str[0] == '\0') {
1090 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1091 "[%d]\n", cipher_code);
1097 int ecryptfs_read_and_validate_header_region(struct inode *inode)
1099 u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1100 u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
1103 rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES,
1105 if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1106 return rc >= 0 ? -EINVAL : rc;
1107 rc = ecryptfs_validate_marker(marker);
1109 ecryptfs_i_size_init(file_size, inode);
1114 ecryptfs_write_header_metadata(char *virt,
1115 struct ecryptfs_crypt_stat *crypt_stat,
1118 u32 header_extent_size;
1119 u16 num_header_extents_at_front;
1121 header_extent_size = (u32)crypt_stat->extent_size;
1122 num_header_extents_at_front =
1123 (u16)(crypt_stat->metadata_size / crypt_stat->extent_size);
1124 put_unaligned_be32(header_extent_size, virt);
1126 put_unaligned_be16(num_header_extents_at_front, virt);
1130 struct kmem_cache *ecryptfs_header_cache;
1133 * ecryptfs_write_headers_virt
1134 * @page_virt: The virtual address to write the headers to
1135 * @max: The size of memory allocated at page_virt
1136 * @size: Set to the number of bytes written by this function
1137 * @crypt_stat: The cryptographic context
1138 * @ecryptfs_dentry: The eCryptfs dentry
1143 * Octets 0-7: Unencrypted file size (big-endian)
1144 * Octets 8-15: eCryptfs special marker
1145 * Octets 16-19: Flags
1146 * Octet 16: File format version number (between 0 and 255)
1147 * Octets 17-18: Reserved
1148 * Octet 19: Bit 1 (lsb): Reserved
1150 * Bits 3-8: Reserved
1151 * Octets 20-23: Header extent size (big-endian)
1152 * Octets 24-25: Number of header extents at front of file
1154 * Octet 26: Begin RFC 2440 authentication token packet set
1156 * Lower data (CBC encrypted)
1158 * Lower data (CBC encrypted)
1161 * Returns zero on success
1163 static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1165 struct ecryptfs_crypt_stat *crypt_stat,
1166 struct dentry *ecryptfs_dentry)
1172 offset = ECRYPTFS_FILE_SIZE_BYTES;
1173 write_ecryptfs_marker((page_virt + offset), &written);
1175 ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat,
1178 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1181 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1182 ecryptfs_dentry, &written,
1185 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1186 "set; rc = [%d]\n", rc);
1195 ecryptfs_write_metadata_to_contents(struct inode *ecryptfs_inode,
1196 char *virt, size_t virt_len)
1200 rc = ecryptfs_write_lower(ecryptfs_inode, virt,
1203 printk(KERN_ERR "%s: Error attempting to write header "
1204 "information to lower file; rc = [%d]\n", __func__, rc);
1211 ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1212 char *page_virt, size_t size)
1216 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1221 static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1226 page = alloc_pages(gfp_mask | __GFP_ZERO, order);
1228 return (unsigned long) page_address(page);
1233 * ecryptfs_write_metadata
1234 * @ecryptfs_dentry: The eCryptfs dentry, which should be negative
1235 * @ecryptfs_inode: The newly created eCryptfs inode
1237 * Write the file headers out. This will likely involve a userspace
1238 * callout, in which the session key is encrypted with one or more
1239 * public keys and/or the passphrase necessary to do the encryption is
1240 * retrieved via a prompt. Exactly what happens at this point should
1241 * be policy-dependent.
1243 * Returns zero on success; non-zero on error
1245 int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
1246 struct inode *ecryptfs_inode)
1248 struct ecryptfs_crypt_stat *crypt_stat =
1249 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1256 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1257 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
1258 printk(KERN_ERR "Key is invalid; bailing out\n");
1263 printk(KERN_WARNING "%s: Encrypted flag not set\n",
1268 virt_len = crypt_stat->metadata_size;
1269 order = get_order(virt_len);
1270 /* Released in this function */
1271 virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
1273 printk(KERN_ERR "%s: Out of memory\n", __func__);
1277 /* Zeroed page ensures the in-header unencrypted i_size is set to 0 */
1278 rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
1281 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
1285 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1286 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt,
1289 rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt,
1292 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
1293 "rc = [%d]\n", __func__, rc);
1297 free_pages((unsigned long)virt, order);
1302 #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1303 #define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1304 static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
1305 char *virt, int *bytes_read,
1306 int validate_header_size)
1309 u32 header_extent_size;
1310 u16 num_header_extents_at_front;
1312 header_extent_size = get_unaligned_be32(virt);
1313 virt += sizeof(__be32);
1314 num_header_extents_at_front = get_unaligned_be16(virt);
1315 crypt_stat->metadata_size = (((size_t)num_header_extents_at_front
1316 * (size_t)header_extent_size));
1317 (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
1318 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
1319 && (crypt_stat->metadata_size
1320 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
1322 printk(KERN_WARNING "Invalid header size: [%zd]\n",
1323 crypt_stat->metadata_size);
1329 * set_default_header_data
1330 * @crypt_stat: The cryptographic context
1332 * For version 0 file format; this function is only for backwards
1333 * compatibility for files created with the prior versions of
1336 static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1338 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
1341 void ecryptfs_i_size_init(const char *page_virt, struct inode *inode)
1343 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1344 struct ecryptfs_crypt_stat *crypt_stat;
1347 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
1349 &ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat;
1350 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
1351 file_size = i_size_read(ecryptfs_inode_to_lower(inode));
1352 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1353 file_size += crypt_stat->metadata_size;
1355 file_size = get_unaligned_be64(page_virt);
1356 i_size_write(inode, (loff_t)file_size);
1357 crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED;
1361 * ecryptfs_read_headers_virt
1362 * @page_virt: The virtual address into which to read the headers
1363 * @crypt_stat: The cryptographic context
1364 * @ecryptfs_dentry: The eCryptfs dentry
1365 * @validate_header_size: Whether to validate the header size while reading
1367 * Read/parse the header data. The header format is detailed in the
1368 * comment block for the ecryptfs_write_headers_virt() function.
1370 * Returns zero on success
1372 static int ecryptfs_read_headers_virt(char *page_virt,
1373 struct ecryptfs_crypt_stat *crypt_stat,
1374 struct dentry *ecryptfs_dentry,
1375 int validate_header_size)
1381 ecryptfs_set_default_sizes(crypt_stat);
1382 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1383 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1384 offset = ECRYPTFS_FILE_SIZE_BYTES;
1385 rc = ecryptfs_validate_marker(page_virt + offset);
1388 if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED))
1389 ecryptfs_i_size_init(page_virt, ecryptfs_dentry->d_inode);
1390 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1391 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1394 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1397 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1398 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1399 "file version [%d] is supported by this "
1400 "version of eCryptfs\n",
1401 crypt_stat->file_version,
1402 ECRYPTFS_SUPPORTED_FILE_VERSION);
1406 offset += bytes_read;
1407 if (crypt_stat->file_version >= 1) {
1408 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
1409 &bytes_read, validate_header_size);
1411 ecryptfs_printk(KERN_WARNING, "Error reading header "
1412 "metadata; rc = [%d]\n", rc);
1414 offset += bytes_read;
1416 set_default_header_data(crypt_stat);
1417 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1424 * ecryptfs_read_xattr_region
1425 * @page_virt: The vitual address into which to read the xattr data
1426 * @ecryptfs_inode: The eCryptfs inode
1428 * Attempts to read the crypto metadata from the extended attribute
1429 * region of the lower file.
1431 * Returns zero on success; non-zero on error
1433 int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
1435 struct dentry *lower_dentry =
1436 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
1440 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1441 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
1443 if (unlikely(ecryptfs_verbosity > 0))
1444 printk(KERN_INFO "Error attempting to read the [%s] "
1445 "xattr from the lower file; return value = "
1446 "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
1454 int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
1455 struct inode *inode)
1457 u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1458 u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
1461 rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1462 ECRYPTFS_XATTR_NAME, file_size,
1463 ECRYPTFS_SIZE_AND_MARKER_BYTES);
1464 if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1465 return rc >= 0 ? -EINVAL : rc;
1466 rc = ecryptfs_validate_marker(marker);
1468 ecryptfs_i_size_init(file_size, inode);
1473 * ecryptfs_read_metadata
1475 * Common entry point for reading file metadata. From here, we could
1476 * retrieve the header information from the header region of the file,
1477 * the xattr region of the file, or some other repostory that is
1478 * stored separately from the file itself. The current implementation
1479 * supports retrieving the metadata information from the file contents
1480 * and from the xattr region.
1482 * Returns zero if valid headers found and parsed; non-zero otherwise
1484 int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
1488 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
1489 struct ecryptfs_crypt_stat *crypt_stat =
1490 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1491 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1492 &ecryptfs_superblock_to_private(
1493 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1495 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1497 /* Read the first page from the underlying file */
1498 page_virt = kmem_cache_alloc(ecryptfs_header_cache, GFP_USER);
1501 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
1505 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1508 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1510 ECRYPTFS_VALIDATE_HEADER_SIZE);
1512 /* metadata is not in the file header, so try xattrs */
1513 memset(page_virt, 0, PAGE_CACHE_SIZE);
1514 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
1516 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1517 "file header region or xattr region, inode %lu\n",
1518 ecryptfs_inode->i_ino);
1522 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1524 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1526 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1527 "file xattr region either, inode %lu\n",
1528 ecryptfs_inode->i_ino);
1531 if (crypt_stat->mount_crypt_stat->flags
1532 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1533 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1535 printk(KERN_WARNING "Attempt to access file with "
1536 "crypto metadata only in the extended attribute "
1537 "region, but eCryptfs was mounted without "
1538 "xattr support enabled. eCryptfs will not treat "
1539 "this like an encrypted file, inode %lu\n",
1540 ecryptfs_inode->i_ino);
1546 memset(page_virt, 0, PAGE_CACHE_SIZE);
1547 kmem_cache_free(ecryptfs_header_cache, page_virt);
1553 * ecryptfs_encrypt_filename - encrypt filename
1555 * CBC-encrypts the filename. We do not want to encrypt the same
1556 * filename with the same key and IV, which may happen with hard
1557 * links, so we prepend random bits to each filename.
1559 * Returns zero on success; non-zero otherwise
1562 ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1563 struct ecryptfs_crypt_stat *crypt_stat,
1564 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1568 filename->encrypted_filename = NULL;
1569 filename->encrypted_filename_size = 0;
1570 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
1571 || (mount_crypt_stat && (mount_crypt_stat->flags
1572 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
1574 size_t remaining_bytes;
1576 rc = ecryptfs_write_tag_70_packet(
1578 &filename->encrypted_filename_size,
1579 mount_crypt_stat, NULL,
1580 filename->filename_size);
1582 printk(KERN_ERR "%s: Error attempting to get packet "
1583 "size for tag 72; rc = [%d]\n", __func__,
1585 filename->encrypted_filename_size = 0;
1588 filename->encrypted_filename =
1589 kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1590 if (!filename->encrypted_filename) {
1591 printk(KERN_ERR "%s: Out of memory whilst attempting "
1592 "to kmalloc [%zd] bytes\n", __func__,
1593 filename->encrypted_filename_size);
1597 remaining_bytes = filename->encrypted_filename_size;
1598 rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
1603 filename->filename_size);
1605 printk(KERN_ERR "%s: Error attempting to generate "
1606 "tag 70 packet; rc = [%d]\n", __func__,
1608 kfree(filename->encrypted_filename);
1609 filename->encrypted_filename = NULL;
1610 filename->encrypted_filename_size = 0;
1613 filename->encrypted_filename_size = packet_size;
1615 printk(KERN_ERR "%s: No support for requested filename "
1616 "encryption method in this release\n", __func__);
1624 static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1625 const char *name, size_t name_size)
1629 (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
1630 if (!(*copied_name)) {
1634 memcpy((void *)(*copied_name), (void *)name, name_size);
1635 (*copied_name)[(name_size)] = '\0'; /* Only for convenience
1636 * in printing out the
1639 (*copied_name_size) = name_size;
1645 * ecryptfs_process_key_cipher - Perform key cipher initialization.
1646 * @key_tfm: Crypto context for key material, set by this function
1647 * @cipher_name: Name of the cipher
1648 * @key_size: Size of the key in bytes
1650 * Returns zero on success. Any crypto_tfm structs allocated here
1651 * should be released by other functions, such as on a superblock put
1652 * event, regardless of whether this function succeeds for fails.
1655 ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1656 char *cipher_name, size_t *key_size)
1658 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
1659 char *full_alg_name = NULL;
1663 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
1665 printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
1666 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
1669 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1673 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1674 if (IS_ERR(*key_tfm)) {
1675 rc = PTR_ERR(*key_tfm);
1676 printk(KERN_ERR "Unable to allocate crypto cipher with name "
1677 "[%s]; rc = [%d]\n", full_alg_name, rc);
1680 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1681 if (*key_size == 0) {
1682 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1684 *key_size = alg->max_keysize;
1686 get_random_bytes(dummy_key, *key_size);
1687 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
1689 printk(KERN_ERR "Error attempting to set key of size [%zd] for "
1690 "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name,
1696 kfree(full_alg_name);
1700 struct kmem_cache *ecryptfs_key_tfm_cache;
1701 static struct list_head key_tfm_list;
1702 struct mutex key_tfm_list_mutex;
1704 int __init ecryptfs_init_crypto(void)
1706 mutex_init(&key_tfm_list_mutex);
1707 INIT_LIST_HEAD(&key_tfm_list);
1712 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1714 * Called only at module unload time
1716 int ecryptfs_destroy_crypto(void)
1718 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1720 mutex_lock(&key_tfm_list_mutex);
1721 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1723 list_del(&key_tfm->key_tfm_list);
1724 if (key_tfm->key_tfm)
1725 crypto_free_blkcipher(key_tfm->key_tfm);
1726 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1728 mutex_unlock(&key_tfm_list_mutex);
1733 ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1736 struct ecryptfs_key_tfm *tmp_tfm;
1739 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1741 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1742 if (key_tfm != NULL)
1743 (*key_tfm) = tmp_tfm;
1746 printk(KERN_ERR "Error attempting to allocate from "
1747 "ecryptfs_key_tfm_cache\n");
1750 mutex_init(&tmp_tfm->key_tfm_mutex);
1751 strncpy(tmp_tfm->cipher_name, cipher_name,
1752 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
1753 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
1754 tmp_tfm->key_size = key_size;
1755 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1756 tmp_tfm->cipher_name,
1757 &tmp_tfm->key_size);
1759 printk(KERN_ERR "Error attempting to initialize key TFM "
1760 "cipher with name = [%s]; rc = [%d]\n",
1761 tmp_tfm->cipher_name, rc);
1762 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1763 if (key_tfm != NULL)
1767 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
1773 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1774 * @cipher_name: the name of the cipher to search for
1775 * @key_tfm: set to corresponding tfm if found
1777 * Searches for cached key_tfm matching @cipher_name
1778 * Must be called with &key_tfm_list_mutex held
1779 * Returns 1 if found, with @key_tfm set
1780 * Returns 0 if not found, with @key_tfm set to NULL
1782 int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1784 struct ecryptfs_key_tfm *tmp_key_tfm;
1786 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1788 list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1789 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1791 (*key_tfm) = tmp_key_tfm;
1801 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1803 * @tfm: set to cached tfm found, or new tfm created
1804 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1805 * @cipher_name: the name of the cipher to search for and/or add
1807 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1808 * Searches for cached item first, and creates new if not found.
1809 * Returns 0 on success, non-zero if adding new cipher failed
1811 int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1812 struct mutex **tfm_mutex,
1815 struct ecryptfs_key_tfm *key_tfm;
1819 (*tfm_mutex) = NULL;
1821 mutex_lock(&key_tfm_list_mutex);
1822 if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1823 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1825 printk(KERN_ERR "Error adding new key_tfm to list; "
1830 (*tfm) = key_tfm->key_tfm;
1831 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1833 mutex_unlock(&key_tfm_list_mutex);
1837 /* 64 characters forming a 6-bit target field */
1838 static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1841 "klmnopqrstuvwxyz");
1843 /* We could either offset on every reverse map or just pad some 0x00's
1844 * at the front here */
1845 static const unsigned char filename_rev_map[256] = {
1846 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1847 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1848 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1849 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1850 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1851 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1852 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1853 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1854 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1855 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1856 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1857 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1858 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1859 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1860 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
1861 0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */
1865 * ecryptfs_encode_for_filename
1866 * @dst: Destination location for encoded filename
1867 * @dst_size: Size of the encoded filename in bytes
1868 * @src: Source location for the filename to encode
1869 * @src_size: Size of the source in bytes
1871 static void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
1872 unsigned char *src, size_t src_size)
1875 size_t block_num = 0;
1876 size_t dst_offset = 0;
1877 unsigned char last_block[3];
1879 if (src_size == 0) {
1883 num_blocks = (src_size / 3);
1884 if ((src_size % 3) == 0) {
1885 memcpy(last_block, (&src[src_size - 3]), 3);
1888 last_block[2] = 0x00;
1889 switch (src_size % 3) {
1891 last_block[0] = src[src_size - 1];
1892 last_block[1] = 0x00;
1895 last_block[0] = src[src_size - 2];
1896 last_block[1] = src[src_size - 1];
1899 (*dst_size) = (num_blocks * 4);
1902 while (block_num < num_blocks) {
1903 unsigned char *src_block;
1904 unsigned char dst_block[4];
1906 if (block_num == (num_blocks - 1))
1907 src_block = last_block;
1909 src_block = &src[block_num * 3];
1910 dst_block[0] = ((src_block[0] >> 2) & 0x3F);
1911 dst_block[1] = (((src_block[0] << 4) & 0x30)
1912 | ((src_block[1] >> 4) & 0x0F));
1913 dst_block[2] = (((src_block[1] << 2) & 0x3C)
1914 | ((src_block[2] >> 6) & 0x03));
1915 dst_block[3] = (src_block[2] & 0x3F);
1916 dst[dst_offset++] = portable_filename_chars[dst_block[0]];
1917 dst[dst_offset++] = portable_filename_chars[dst_block[1]];
1918 dst[dst_offset++] = portable_filename_chars[dst_block[2]];
1919 dst[dst_offset++] = portable_filename_chars[dst_block[3]];
1926 static size_t ecryptfs_max_decoded_size(size_t encoded_size)
1928 /* Not exact; conservatively long. Every block of 4
1929 * encoded characters decodes into a block of 3
1930 * decoded characters. This segment of code provides
1931 * the caller with the maximum amount of allocated
1932 * space that @dst will need to point to in a
1933 * subsequent call. */
1934 return ((encoded_size + 1) * 3) / 4;
1938 * ecryptfs_decode_from_filename
1939 * @dst: If NULL, this function only sets @dst_size and returns. If
1940 * non-NULL, this function decodes the encoded octets in @src
1941 * into the memory that @dst points to.
1942 * @dst_size: Set to the size of the decoded string.
1943 * @src: The encoded set of octets to decode.
1944 * @src_size: The size of the encoded set of octets to decode.
1947 ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
1948 const unsigned char *src, size_t src_size)
1950 u8 current_bit_offset = 0;
1951 size_t src_byte_offset = 0;
1952 size_t dst_byte_offset = 0;
1955 (*dst_size) = ecryptfs_max_decoded_size(src_size);
1958 while (src_byte_offset < src_size) {
1959 unsigned char src_byte =
1960 filename_rev_map[(int)src[src_byte_offset]];
1962 switch (current_bit_offset) {
1964 dst[dst_byte_offset] = (src_byte << 2);
1965 current_bit_offset = 6;
1968 dst[dst_byte_offset++] |= (src_byte >> 4);
1969 dst[dst_byte_offset] = ((src_byte & 0xF)
1971 current_bit_offset = 4;
1974 dst[dst_byte_offset++] |= (src_byte >> 2);
1975 dst[dst_byte_offset] = (src_byte << 6);
1976 current_bit_offset = 2;
1979 dst[dst_byte_offset++] |= (src_byte);
1980 dst[dst_byte_offset] = 0;
1981 current_bit_offset = 0;
1986 (*dst_size) = dst_byte_offset;
1992 * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
1993 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
1994 * @name: The plaintext name
1995 * @length: The length of the plaintext
1996 * @encoded_name: The encypted name
1998 * Encrypts and encodes a filename into something that constitutes a
1999 * valid filename for a filesystem, with printable characters.
2001 * We assume that we have a properly initialized crypto context,
2002 * pointed to by crypt_stat->tfm.
2004 * Returns zero on success; non-zero on otherwise
2006 int ecryptfs_encrypt_and_encode_filename(
2007 char **encoded_name,
2008 size_t *encoded_name_size,
2009 struct ecryptfs_crypt_stat *crypt_stat,
2010 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2011 const char *name, size_t name_size)
2013 size_t encoded_name_no_prefix_size;
2016 (*encoded_name) = NULL;
2017 (*encoded_name_size) = 0;
2018 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
2019 || (mount_crypt_stat && (mount_crypt_stat->flags
2020 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) {
2021 struct ecryptfs_filename *filename;
2023 filename = kzalloc(sizeof(*filename), GFP_KERNEL);
2025 printk(KERN_ERR "%s: Out of memory whilst attempting "
2026 "to kzalloc [%zd] bytes\n", __func__,
2031 filename->filename = (char *)name;
2032 filename->filename_size = name_size;
2033 rc = ecryptfs_encrypt_filename(filename, crypt_stat,
2036 printk(KERN_ERR "%s: Error attempting to encrypt "
2037 "filename; rc = [%d]\n", __func__, rc);
2041 ecryptfs_encode_for_filename(
2042 NULL, &encoded_name_no_prefix_size,
2043 filename->encrypted_filename,
2044 filename->encrypted_filename_size);
2045 if ((crypt_stat && (crypt_stat->flags
2046 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2047 || (mount_crypt_stat
2048 && (mount_crypt_stat->flags
2049 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)))
2050 (*encoded_name_size) =
2051 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2052 + encoded_name_no_prefix_size);
2054 (*encoded_name_size) =
2055 (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2056 + encoded_name_no_prefix_size);
2057 (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
2058 if (!(*encoded_name)) {
2059 printk(KERN_ERR "%s: Out of memory whilst attempting "
2060 "to kzalloc [%zd] bytes\n", __func__,
2061 (*encoded_name_size));
2063 kfree(filename->encrypted_filename);
2067 if ((crypt_stat && (crypt_stat->flags
2068 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2069 || (mount_crypt_stat
2070 && (mount_crypt_stat->flags
2071 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
2072 memcpy((*encoded_name),
2073 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2074 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
2075 ecryptfs_encode_for_filename(
2077 + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
2078 &encoded_name_no_prefix_size,
2079 filename->encrypted_filename,
2080 filename->encrypted_filename_size);
2081 (*encoded_name_size) =
2082 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2083 + encoded_name_no_prefix_size);
2084 (*encoded_name)[(*encoded_name_size)] = '\0';
2089 printk(KERN_ERR "%s: Error attempting to encode "
2090 "encrypted filename; rc = [%d]\n", __func__,
2092 kfree((*encoded_name));
2093 (*encoded_name) = NULL;
2094 (*encoded_name_size) = 0;
2096 kfree(filename->encrypted_filename);
2099 rc = ecryptfs_copy_filename(encoded_name,
2108 * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
2109 * @plaintext_name: The plaintext name
2110 * @plaintext_name_size: The plaintext name size
2111 * @ecryptfs_dir_dentry: eCryptfs directory dentry
2112 * @name: The filename in cipher text
2113 * @name_size: The cipher text name size
2115 * Decrypts and decodes the filename.
2117 * Returns zero on error; non-zero otherwise
2119 int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
2120 size_t *plaintext_name_size,
2121 struct dentry *ecryptfs_dir_dentry,
2122 const char *name, size_t name_size)
2124 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2125 &ecryptfs_superblock_to_private(
2126 ecryptfs_dir_dentry->d_sb)->mount_crypt_stat;
2128 size_t decoded_name_size;
2132 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
2133 && !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
2134 && (name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
2135 && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2136 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
2137 const char *orig_name = name;
2138 size_t orig_name_size = name_size;
2140 name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2141 name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2142 ecryptfs_decode_from_filename(NULL, &decoded_name_size,
2144 decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
2145 if (!decoded_name) {
2146 printk(KERN_ERR "%s: Out of memory whilst attempting "
2147 "to kmalloc [%zd] bytes\n", __func__,
2152 ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
2154 rc = ecryptfs_parse_tag_70_packet(plaintext_name,
2155 plaintext_name_size,
2161 printk(KERN_INFO "%s: Could not parse tag 70 packet "
2162 "from filename; copying through filename "
2163 "as-is\n", __func__);
2164 rc = ecryptfs_copy_filename(plaintext_name,
2165 plaintext_name_size,
2166 orig_name, orig_name_size);
2170 rc = ecryptfs_copy_filename(plaintext_name,
2171 plaintext_name_size,
2176 kfree(decoded_name);
2181 #define ENC_NAME_MAX_BLOCKLEN_8_OR_16 143
2183 int ecryptfs_set_f_namelen(long *namelen, long lower_namelen,
2184 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
2186 struct blkcipher_desc desc;
2187 struct mutex *tfm_mutex;
2188 size_t cipher_blocksize;
2191 if (!(mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
2192 (*namelen) = lower_namelen;
2196 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
2197 mount_crypt_stat->global_default_fn_cipher_name);
2203 mutex_lock(tfm_mutex);
2204 cipher_blocksize = crypto_blkcipher_blocksize(desc.tfm);
2205 mutex_unlock(tfm_mutex);
2207 /* Return an exact amount for the common cases */
2208 if (lower_namelen == NAME_MAX
2209 && (cipher_blocksize == 8 || cipher_blocksize == 16)) {
2210 (*namelen) = ENC_NAME_MAX_BLOCKLEN_8_OR_16;
2214 /* Return a safe estimate for the uncommon cases */
2215 (*namelen) = lower_namelen;
2216 (*namelen) -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2217 /* Since this is the max decoded size, subtract 1 "decoded block" len */
2218 (*namelen) = ecryptfs_max_decoded_size(*namelen) - 3;
2219 (*namelen) -= ECRYPTFS_TAG_70_MAX_METADATA_SIZE;
2220 (*namelen) -= ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES;
2221 /* Worst case is that the filename is padded nearly a full block size */
2222 (*namelen) -= cipher_blocksize - 1;