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
26 #include <crypto/hash.h>
27 #include <crypto/skcipher.h>
29 #include <linux/mount.h>
30 #include <linux/pagemap.h>
31 #include <linux/random.h>
32 #include <linux/compiler.h>
33 #include <linux/key.h>
34 #include <linux/namei.h>
35 #include <linux/file.h>
36 #include <linux/scatterlist.h>
37 #include <linux/slab.h>
38 #include <asm/unaligned.h>
39 #include "ecryptfs_kernel.h"
46 * @dst: Buffer to take the bytes from src hex; must be at least of
48 * @src: Buffer to be converted from a hex string representation to raw value
49 * @dst_size: size of dst buffer, or number of hex characters pairs to convert
51 void ecryptfs_from_hex(char *dst, char *src, int dst_size)
56 for (x = 0; x < dst_size; x++) {
58 tmp[1] = src[x * 2 + 1];
59 dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
63 static int ecryptfs_hash_digest(struct crypto_shash *tfm,
64 char *src, int len, char *dst)
66 SHASH_DESC_ON_STACK(desc, tfm);
70 desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
71 err = crypto_shash_digest(desc, src, len, dst);
72 shash_desc_zero(desc);
77 * ecryptfs_calculate_md5 - calculates the md5 of @src
78 * @dst: Pointer to 16 bytes of allocated memory
79 * @crypt_stat: Pointer to crypt_stat struct for the current inode
80 * @src: Data to be md5'd
81 * @len: Length of @src
83 * Uses the allocated crypto context that crypt_stat references to
84 * generate the MD5 sum of the contents of src.
86 static int ecryptfs_calculate_md5(char *dst,
87 struct ecryptfs_crypt_stat *crypt_stat,
90 struct crypto_shash *tfm;
93 tfm = crypt_stat->hash_tfm;
94 rc = ecryptfs_hash_digest(tfm, src, len, dst);
97 "%s: Error computing crypto hash; rc = [%d]\n",
105 static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
107 char *chaining_modifier)
109 int cipher_name_len = strlen(cipher_name);
110 int chaining_modifier_len = strlen(chaining_modifier);
111 int algified_name_len;
114 algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
115 (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
116 if (!(*algified_name)) {
120 snprintf((*algified_name), algified_name_len, "%s(%s)",
121 chaining_modifier, cipher_name);
129 * @iv: destination for the derived iv vale
130 * @crypt_stat: Pointer to crypt_stat struct for the current inode
131 * @offset: Offset of the extent whose IV we are to derive
133 * Generate the initialization vector from the given root IV and page
136 * Returns zero on success; non-zero on error.
138 int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
142 char dst[MD5_DIGEST_SIZE];
143 char src[ECRYPTFS_MAX_IV_BYTES + 16];
145 if (unlikely(ecryptfs_verbosity > 0)) {
146 ecryptfs_printk(KERN_DEBUG, "root iv:\n");
147 ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
149 /* TODO: It is probably secure to just cast the least
150 * significant bits of the root IV into an unsigned long and
151 * add the offset to that rather than go through all this
152 * hashing business. -Halcrow */
153 memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
154 memset((src + crypt_stat->iv_bytes), 0, 16);
155 snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
156 if (unlikely(ecryptfs_verbosity > 0)) {
157 ecryptfs_printk(KERN_DEBUG, "source:\n");
158 ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
160 rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
161 (crypt_stat->iv_bytes + 16));
163 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
164 "MD5 while generating IV for a page\n");
167 memcpy(iv, dst, crypt_stat->iv_bytes);
168 if (unlikely(ecryptfs_verbosity > 0)) {
169 ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
170 ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
177 * ecryptfs_init_crypt_stat
178 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
180 * Initialize the crypt_stat structure.
182 int ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
184 struct crypto_shash *tfm;
187 tfm = crypto_alloc_shash(ECRYPTFS_DEFAULT_HASH, 0, 0);
190 ecryptfs_printk(KERN_ERR, "Error attempting to "
191 "allocate crypto context; rc = [%d]\n",
196 memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
197 INIT_LIST_HEAD(&crypt_stat->keysig_list);
198 mutex_init(&crypt_stat->keysig_list_mutex);
199 mutex_init(&crypt_stat->cs_mutex);
200 mutex_init(&crypt_stat->cs_tfm_mutex);
201 crypt_stat->hash_tfm = tfm;
202 crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
208 * ecryptfs_destroy_crypt_stat
209 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
211 * Releases all memory associated with a crypt_stat struct.
213 void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
215 struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
217 crypto_free_skcipher(crypt_stat->tfm);
218 crypto_free_shash(crypt_stat->hash_tfm);
219 list_for_each_entry_safe(key_sig, key_sig_tmp,
220 &crypt_stat->keysig_list, crypt_stat_list) {
221 list_del(&key_sig->crypt_stat_list);
222 kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
224 memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
227 void ecryptfs_destroy_mount_crypt_stat(
228 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
230 struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
232 if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
234 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
235 list_for_each_entry_safe(auth_tok, auth_tok_tmp,
236 &mount_crypt_stat->global_auth_tok_list,
237 mount_crypt_stat_list) {
238 list_del(&auth_tok->mount_crypt_stat_list);
239 if (!(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
240 key_put(auth_tok->global_auth_tok_key);
241 kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
243 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
244 memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
248 * virt_to_scatterlist
249 * @addr: Virtual address
250 * @size: Size of data; should be an even multiple of the block size
251 * @sg: Pointer to scatterlist array; set to NULL to obtain only
252 * the number of scatterlist structs required in array
253 * @sg_size: Max array size
255 * Fills in a scatterlist array with page references for a passed
258 * Returns the number of scatterlist structs in array used
260 int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
266 int remainder_of_page;
268 sg_init_table(sg, sg_size);
270 while (size > 0 && i < sg_size) {
271 pg = virt_to_page(addr);
272 offset = offset_in_page(addr);
273 sg_set_page(&sg[i], pg, 0, offset);
274 remainder_of_page = PAGE_SIZE - offset;
275 if (size >= remainder_of_page) {
276 sg[i].length = remainder_of_page;
277 addr += remainder_of_page;
278 size -= remainder_of_page;
291 struct extent_crypt_result {
292 struct completion completion;
296 static void extent_crypt_complete(struct crypto_async_request *req, int rc)
298 struct extent_crypt_result *ecr = req->data;
300 if (rc == -EINPROGRESS)
304 complete(&ecr->completion);
309 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
310 * @dst_sg: Destination of the data after performing the crypto operation
311 * @src_sg: Data to be encrypted or decrypted
312 * @size: Length of data
314 * @op: ENCRYPT or DECRYPT to indicate the desired operation
316 * Returns the number of bytes encrypted or decrypted; negative value on error
318 static int crypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
319 struct scatterlist *dst_sg,
320 struct scatterlist *src_sg, int size,
321 unsigned char *iv, int op)
323 struct skcipher_request *req = NULL;
324 struct extent_crypt_result ecr;
327 BUG_ON(!crypt_stat || !crypt_stat->tfm
328 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
329 if (unlikely(ecryptfs_verbosity > 0)) {
330 ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
331 crypt_stat->key_size);
332 ecryptfs_dump_hex(crypt_stat->key,
333 crypt_stat->key_size);
336 init_completion(&ecr.completion);
338 mutex_lock(&crypt_stat->cs_tfm_mutex);
339 req = skcipher_request_alloc(crypt_stat->tfm, GFP_NOFS);
341 mutex_unlock(&crypt_stat->cs_tfm_mutex);
346 skcipher_request_set_callback(req,
347 CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
348 extent_crypt_complete, &ecr);
349 /* Consider doing this once, when the file is opened */
350 if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
351 rc = crypto_skcipher_setkey(crypt_stat->tfm, crypt_stat->key,
352 crypt_stat->key_size);
354 ecryptfs_printk(KERN_ERR,
355 "Error setting key; rc = [%d]\n",
357 mutex_unlock(&crypt_stat->cs_tfm_mutex);
361 crypt_stat->flags |= ECRYPTFS_KEY_SET;
363 mutex_unlock(&crypt_stat->cs_tfm_mutex);
364 skcipher_request_set_crypt(req, src_sg, dst_sg, size, iv);
365 rc = op == ENCRYPT ? crypto_skcipher_encrypt(req) :
366 crypto_skcipher_decrypt(req);
367 if (rc == -EINPROGRESS || rc == -EBUSY) {
368 struct extent_crypt_result *ecr = req->base.data;
370 wait_for_completion(&ecr->completion);
372 reinit_completion(&ecr->completion);
375 skcipher_request_free(req);
380 * lower_offset_for_page
382 * Convert an eCryptfs page index into a lower byte offset
384 static loff_t lower_offset_for_page(struct ecryptfs_crypt_stat *crypt_stat,
387 return ecryptfs_lower_header_size(crypt_stat) +
388 ((loff_t)page->index << PAGE_SHIFT);
393 * @crypt_stat: crypt_stat containing cryptographic context for the
394 * encryption operation
395 * @dst_page: The page to write the result into
396 * @src_page: The page to read from
397 * @extent_offset: Page extent offset for use in generating IV
398 * @op: ENCRYPT or DECRYPT to indicate the desired operation
400 * Encrypts or decrypts one extent of data.
402 * Return zero on success; non-zero otherwise
404 static int crypt_extent(struct ecryptfs_crypt_stat *crypt_stat,
405 struct page *dst_page,
406 struct page *src_page,
407 unsigned long extent_offset, int op)
409 pgoff_t page_index = op == ENCRYPT ? src_page->index : dst_page->index;
411 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
412 struct scatterlist src_sg, dst_sg;
413 size_t extent_size = crypt_stat->extent_size;
416 extent_base = (((loff_t)page_index) * (PAGE_SIZE / extent_size));
417 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
418 (extent_base + extent_offset));
420 ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
421 "extent [0x%.16llx]; rc = [%d]\n",
422 (unsigned long long)(extent_base + extent_offset), rc);
426 sg_init_table(&src_sg, 1);
427 sg_init_table(&dst_sg, 1);
429 sg_set_page(&src_sg, src_page, extent_size,
430 extent_offset * extent_size);
431 sg_set_page(&dst_sg, dst_page, extent_size,
432 extent_offset * extent_size);
434 rc = crypt_scatterlist(crypt_stat, &dst_sg, &src_sg, extent_size,
437 printk(KERN_ERR "%s: Error attempting to crypt page with "
438 "page_index = [%ld], extent_offset = [%ld]; "
439 "rc = [%d]\n", __func__, page_index, extent_offset, rc);
448 * ecryptfs_encrypt_page
449 * @page: Page mapped from the eCryptfs inode for the file; contains
450 * decrypted content that needs to be encrypted (to a temporary
451 * page; not in place) and written out to the lower file
453 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
454 * that eCryptfs pages may straddle the lower pages -- for instance,
455 * if the file was created on a machine with an 8K page size
456 * (resulting in an 8K header), and then the file is copied onto a
457 * host with a 32K page size, then when reading page 0 of the eCryptfs
458 * file, 24K of page 0 of the lower file will be read and decrypted,
459 * and then 8K of page 1 of the lower file will be read and decrypted.
461 * Returns zero on success; negative on error
463 int ecryptfs_encrypt_page(struct page *page)
465 struct inode *ecryptfs_inode;
466 struct ecryptfs_crypt_stat *crypt_stat;
467 char *enc_extent_virt;
468 struct page *enc_extent_page = NULL;
469 loff_t extent_offset;
473 ecryptfs_inode = page->mapping->host;
475 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
476 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
477 enc_extent_page = alloc_page(GFP_USER);
478 if (!enc_extent_page) {
480 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
481 "encrypted extent\n");
485 for (extent_offset = 0;
486 extent_offset < (PAGE_SIZE / crypt_stat->extent_size);
488 rc = crypt_extent(crypt_stat, enc_extent_page, page,
489 extent_offset, ENCRYPT);
491 printk(KERN_ERR "%s: Error encrypting extent; "
492 "rc = [%d]\n", __func__, rc);
497 lower_offset = lower_offset_for_page(crypt_stat, page);
498 enc_extent_virt = kmap(enc_extent_page);
499 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset,
501 kunmap(enc_extent_page);
503 ecryptfs_printk(KERN_ERR,
504 "Error attempting to write lower page; rc = [%d]\n",
510 if (enc_extent_page) {
511 __free_page(enc_extent_page);
517 * ecryptfs_decrypt_page
518 * @page: Page mapped from the eCryptfs inode for the file; data read
519 * and decrypted from the lower file will be written into this
522 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
523 * that eCryptfs pages may straddle the lower pages -- for instance,
524 * if the file was created on a machine with an 8K page size
525 * (resulting in an 8K header), and then the file is copied onto a
526 * host with a 32K page size, then when reading page 0 of the eCryptfs
527 * file, 24K of page 0 of the lower file will be read and decrypted,
528 * and then 8K of page 1 of the lower file will be read and decrypted.
530 * Returns zero on success; negative on error
532 int ecryptfs_decrypt_page(struct page *page)
534 struct inode *ecryptfs_inode;
535 struct ecryptfs_crypt_stat *crypt_stat;
537 unsigned long extent_offset;
541 ecryptfs_inode = page->mapping->host;
543 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
544 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
546 lower_offset = lower_offset_for_page(crypt_stat, page);
547 page_virt = kmap(page);
548 rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_SIZE,
552 ecryptfs_printk(KERN_ERR,
553 "Error attempting to read lower page; rc = [%d]\n",
558 for (extent_offset = 0;
559 extent_offset < (PAGE_SIZE / crypt_stat->extent_size);
561 rc = crypt_extent(crypt_stat, page, page,
562 extent_offset, DECRYPT);
564 printk(KERN_ERR "%s: Error encrypting extent; "
565 "rc = [%d]\n", __func__, rc);
573 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
576 * ecryptfs_init_crypt_ctx
577 * @crypt_stat: Uninitialized crypt stats structure
579 * Initialize the crypto context.
581 * TODO: Performance: Keep a cache of initialized cipher contexts;
582 * only init if needed
584 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
589 ecryptfs_printk(KERN_DEBUG,
590 "Initializing cipher [%s]; strlen = [%d]; "
591 "key_size_bits = [%zd]\n",
592 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
593 crypt_stat->key_size << 3);
594 mutex_lock(&crypt_stat->cs_tfm_mutex);
595 if (crypt_stat->tfm) {
599 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
600 crypt_stat->cipher, "cbc");
603 crypt_stat->tfm = crypto_alloc_skcipher(full_alg_name, 0, 0);
604 if (IS_ERR(crypt_stat->tfm)) {
605 rc = PTR_ERR(crypt_stat->tfm);
606 crypt_stat->tfm = NULL;
607 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
608 "Error initializing cipher [%s]\n",
612 crypto_skcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
615 kfree(full_alg_name);
617 mutex_unlock(&crypt_stat->cs_tfm_mutex);
621 static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
625 crypt_stat->extent_mask = 0xFFFFFFFF;
626 crypt_stat->extent_shift = 0;
627 if (crypt_stat->extent_size == 0)
629 extent_size_tmp = crypt_stat->extent_size;
630 while ((extent_size_tmp & 0x01) == 0) {
631 extent_size_tmp >>= 1;
632 crypt_stat->extent_mask <<= 1;
633 crypt_stat->extent_shift++;
637 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
639 /* Default values; may be overwritten as we are parsing the
641 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
642 set_extent_mask_and_shift(crypt_stat);
643 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
644 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
645 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
647 if (PAGE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
648 crypt_stat->metadata_size =
649 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
651 crypt_stat->metadata_size = PAGE_SIZE;
656 * ecryptfs_compute_root_iv
659 * On error, sets the root IV to all 0's.
661 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
664 char dst[MD5_DIGEST_SIZE];
666 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
667 BUG_ON(crypt_stat->iv_bytes <= 0);
668 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
670 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
671 "cannot generate root IV\n");
674 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
675 crypt_stat->key_size);
677 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
678 "MD5 while generating root IV\n");
681 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
684 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
685 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
690 static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
692 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
693 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
694 ecryptfs_compute_root_iv(crypt_stat);
695 if (unlikely(ecryptfs_verbosity > 0)) {
696 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
697 ecryptfs_dump_hex(crypt_stat->key,
698 crypt_stat->key_size);
703 * ecryptfs_copy_mount_wide_flags_to_inode_flags
704 * @crypt_stat: The inode's cryptographic context
705 * @mount_crypt_stat: The mount point's cryptographic context
707 * This function propagates the mount-wide flags to individual inode
710 static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
711 struct ecryptfs_crypt_stat *crypt_stat,
712 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
714 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
715 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
716 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
717 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
718 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
719 crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
720 if (mount_crypt_stat->flags
721 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
722 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
723 else if (mount_crypt_stat->flags
724 & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
725 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
729 static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
730 struct ecryptfs_crypt_stat *crypt_stat,
731 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
733 struct ecryptfs_global_auth_tok *global_auth_tok;
736 mutex_lock(&crypt_stat->keysig_list_mutex);
737 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
739 list_for_each_entry(global_auth_tok,
740 &mount_crypt_stat->global_auth_tok_list,
741 mount_crypt_stat_list) {
742 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
744 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
746 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
752 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
753 mutex_unlock(&crypt_stat->keysig_list_mutex);
758 * ecryptfs_set_default_crypt_stat_vals
759 * @crypt_stat: The inode's cryptographic context
760 * @mount_crypt_stat: The mount point's cryptographic context
762 * Default values in the event that policy does not override them.
764 static void ecryptfs_set_default_crypt_stat_vals(
765 struct ecryptfs_crypt_stat *crypt_stat,
766 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
768 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
770 ecryptfs_set_default_sizes(crypt_stat);
771 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
772 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
773 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
774 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
775 crypt_stat->mount_crypt_stat = mount_crypt_stat;
779 * ecryptfs_new_file_context
780 * @ecryptfs_inode: The eCryptfs inode
782 * If the crypto context for the file has not yet been established,
783 * this is where we do that. Establishing a new crypto context
784 * involves the following decisions:
785 * - What cipher to use?
786 * - What set of authentication tokens to use?
787 * Here we just worry about getting enough information into the
788 * authentication tokens so that we know that they are available.
789 * We associate the available authentication tokens with the new file
790 * via the set of signatures in the crypt_stat struct. Later, when
791 * the headers are actually written out, we may again defer to
792 * userspace to perform the encryption of the session key; for the
793 * foreseeable future, this will be the case with public key packets.
795 * Returns zero on success; non-zero otherwise
797 int ecryptfs_new_file_context(struct inode *ecryptfs_inode)
799 struct ecryptfs_crypt_stat *crypt_stat =
800 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
801 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
802 &ecryptfs_superblock_to_private(
803 ecryptfs_inode->i_sb)->mount_crypt_stat;
807 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
808 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
809 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
811 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
814 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
815 "to the inode key sigs; rc = [%d]\n", rc);
819 strlen(mount_crypt_stat->global_default_cipher_name);
820 memcpy(crypt_stat->cipher,
821 mount_crypt_stat->global_default_cipher_name,
823 crypt_stat->cipher[cipher_name_len] = '\0';
824 crypt_stat->key_size =
825 mount_crypt_stat->global_default_cipher_key_size;
826 ecryptfs_generate_new_key(crypt_stat);
827 rc = ecryptfs_init_crypt_ctx(crypt_stat);
829 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
830 "context for cipher [%s]: rc = [%d]\n",
831 crypt_stat->cipher, rc);
837 * ecryptfs_validate_marker - check for the ecryptfs marker
838 * @data: The data block in which to check
840 * Returns zero if marker found; -EINVAL if not found
842 static int ecryptfs_validate_marker(char *data)
846 m_1 = get_unaligned_be32(data);
847 m_2 = get_unaligned_be32(data + 4);
848 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
850 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
851 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
852 MAGIC_ECRYPTFS_MARKER);
853 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
854 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
858 struct ecryptfs_flag_map_elem {
863 /* Add support for additional flags by adding elements here. */
864 static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
865 {0x00000001, ECRYPTFS_ENABLE_HMAC},
866 {0x00000002, ECRYPTFS_ENCRYPTED},
867 {0x00000004, ECRYPTFS_METADATA_IN_XATTR},
868 {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
872 * ecryptfs_process_flags
873 * @crypt_stat: The cryptographic context
874 * @page_virt: Source data to be parsed
875 * @bytes_read: Updated with the number of bytes read
877 * Returns zero on success; non-zero if the flag set is invalid
879 static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
880 char *page_virt, int *bytes_read)
886 flags = get_unaligned_be32(page_virt);
887 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
888 / sizeof(struct ecryptfs_flag_map_elem))); i++)
889 if (flags & ecryptfs_flag_map[i].file_flag) {
890 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
892 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
893 /* Version is in top 8 bits of the 32-bit flag vector */
894 crypt_stat->file_version = ((flags >> 24) & 0xFF);
900 * write_ecryptfs_marker
901 * @page_virt: The pointer to in a page to begin writing the marker
902 * @written: Number of bytes written
904 * Marker = 0x3c81b7f5
906 static void write_ecryptfs_marker(char *page_virt, size_t *written)
910 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
911 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
912 put_unaligned_be32(m_1, page_virt);
913 page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
914 put_unaligned_be32(m_2, page_virt);
915 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
918 void ecryptfs_write_crypt_stat_flags(char *page_virt,
919 struct ecryptfs_crypt_stat *crypt_stat,
925 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
926 / sizeof(struct ecryptfs_flag_map_elem))); i++)
927 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
928 flags |= ecryptfs_flag_map[i].file_flag;
929 /* Version is in top 8 bits of the 32-bit flag vector */
930 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
931 put_unaligned_be32(flags, page_virt);
935 struct ecryptfs_cipher_code_str_map_elem {
940 /* Add support for additional ciphers by adding elements here. The
941 * cipher_code is whatever OpenPGP applications use to identify the
942 * ciphers. List in order of probability. */
943 static struct ecryptfs_cipher_code_str_map_elem
944 ecryptfs_cipher_code_str_map[] = {
945 {"aes",RFC2440_CIPHER_AES_128 },
946 {"blowfish", RFC2440_CIPHER_BLOWFISH},
947 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
948 {"cast5", RFC2440_CIPHER_CAST_5},
949 {"twofish", RFC2440_CIPHER_TWOFISH},
950 {"cast6", RFC2440_CIPHER_CAST_6},
951 {"aes", RFC2440_CIPHER_AES_192},
952 {"aes", RFC2440_CIPHER_AES_256}
956 * ecryptfs_code_for_cipher_string
957 * @cipher_name: The string alias for the cipher
958 * @key_bytes: Length of key in bytes; used for AES code selection
960 * Returns zero on no match, or the cipher code on match
962 u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
966 struct ecryptfs_cipher_code_str_map_elem *map =
967 ecryptfs_cipher_code_str_map;
969 if (strcmp(cipher_name, "aes") == 0) {
972 code = RFC2440_CIPHER_AES_128;
975 code = RFC2440_CIPHER_AES_192;
978 code = RFC2440_CIPHER_AES_256;
981 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
982 if (strcmp(cipher_name, map[i].cipher_str) == 0) {
983 code = map[i].cipher_code;
991 * ecryptfs_cipher_code_to_string
992 * @str: Destination to write out the cipher name
993 * @cipher_code: The code to convert to cipher name string
995 * Returns zero on success
997 int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
1003 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1004 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1005 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1006 if (str[0] == '\0') {
1007 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1008 "[%d]\n", cipher_code);
1014 int ecryptfs_read_and_validate_header_region(struct inode *inode)
1016 u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1017 u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
1020 rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES,
1022 if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1023 return rc >= 0 ? -EINVAL : rc;
1024 rc = ecryptfs_validate_marker(marker);
1026 ecryptfs_i_size_init(file_size, inode);
1031 ecryptfs_write_header_metadata(char *virt,
1032 struct ecryptfs_crypt_stat *crypt_stat,
1035 u32 header_extent_size;
1036 u16 num_header_extents_at_front;
1038 header_extent_size = (u32)crypt_stat->extent_size;
1039 num_header_extents_at_front =
1040 (u16)(crypt_stat->metadata_size / crypt_stat->extent_size);
1041 put_unaligned_be32(header_extent_size, virt);
1043 put_unaligned_be16(num_header_extents_at_front, virt);
1047 struct kmem_cache *ecryptfs_header_cache;
1050 * ecryptfs_write_headers_virt
1051 * @page_virt: The virtual address to write the headers to
1052 * @max: The size of memory allocated at page_virt
1053 * @size: Set to the number of bytes written by this function
1054 * @crypt_stat: The cryptographic context
1055 * @ecryptfs_dentry: The eCryptfs dentry
1060 * Octets 0-7: Unencrypted file size (big-endian)
1061 * Octets 8-15: eCryptfs special marker
1062 * Octets 16-19: Flags
1063 * Octet 16: File format version number (between 0 and 255)
1064 * Octets 17-18: Reserved
1065 * Octet 19: Bit 1 (lsb): Reserved
1067 * Bits 3-8: Reserved
1068 * Octets 20-23: Header extent size (big-endian)
1069 * Octets 24-25: Number of header extents at front of file
1071 * Octet 26: Begin RFC 2440 authentication token packet set
1073 * Lower data (CBC encrypted)
1075 * Lower data (CBC encrypted)
1078 * Returns zero on success
1080 static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1082 struct ecryptfs_crypt_stat *crypt_stat,
1083 struct dentry *ecryptfs_dentry)
1089 offset = ECRYPTFS_FILE_SIZE_BYTES;
1090 write_ecryptfs_marker((page_virt + offset), &written);
1092 ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat,
1095 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1098 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1099 ecryptfs_dentry, &written,
1102 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1103 "set; rc = [%d]\n", rc);
1112 ecryptfs_write_metadata_to_contents(struct inode *ecryptfs_inode,
1113 char *virt, size_t virt_len)
1117 rc = ecryptfs_write_lower(ecryptfs_inode, virt,
1120 printk(KERN_ERR "%s: Error attempting to write header "
1121 "information to lower file; rc = [%d]\n", __func__, rc);
1128 ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1129 struct inode *ecryptfs_inode,
1130 char *page_virt, size_t size)
1134 rc = ecryptfs_setxattr(ecryptfs_dentry, ecryptfs_inode,
1135 ECRYPTFS_XATTR_NAME, page_virt, size, 0);
1139 static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1144 page = alloc_pages(gfp_mask | __GFP_ZERO, order);
1146 return (unsigned long) page_address(page);
1151 * ecryptfs_write_metadata
1152 * @ecryptfs_dentry: The eCryptfs dentry, which should be negative
1153 * @ecryptfs_inode: The newly created eCryptfs inode
1155 * Write the file headers out. This will likely involve a userspace
1156 * callout, in which the session key is encrypted with one or more
1157 * public keys and/or the passphrase necessary to do the encryption is
1158 * retrieved via a prompt. Exactly what happens at this point should
1159 * be policy-dependent.
1161 * Returns zero on success; non-zero on error
1163 int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
1164 struct inode *ecryptfs_inode)
1166 struct ecryptfs_crypt_stat *crypt_stat =
1167 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1174 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1175 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
1176 printk(KERN_ERR "Key is invalid; bailing out\n");
1181 printk(KERN_WARNING "%s: Encrypted flag not set\n",
1186 virt_len = crypt_stat->metadata_size;
1187 order = get_order(virt_len);
1188 /* Released in this function */
1189 virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
1191 printk(KERN_ERR "%s: Out of memory\n", __func__);
1195 /* Zeroed page ensures the in-header unencrypted i_size is set to 0 */
1196 rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
1199 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
1203 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1204 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, ecryptfs_inode,
1207 rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt,
1210 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
1211 "rc = [%d]\n", __func__, rc);
1215 free_pages((unsigned long)virt, order);
1220 #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1221 #define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1222 static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
1223 char *virt, int *bytes_read,
1224 int validate_header_size)
1227 u32 header_extent_size;
1228 u16 num_header_extents_at_front;
1230 header_extent_size = get_unaligned_be32(virt);
1231 virt += sizeof(__be32);
1232 num_header_extents_at_front = get_unaligned_be16(virt);
1233 crypt_stat->metadata_size = (((size_t)num_header_extents_at_front
1234 * (size_t)header_extent_size));
1235 (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
1236 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
1237 && (crypt_stat->metadata_size
1238 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
1240 printk(KERN_WARNING "Invalid header size: [%zd]\n",
1241 crypt_stat->metadata_size);
1247 * set_default_header_data
1248 * @crypt_stat: The cryptographic context
1250 * For version 0 file format; this function is only for backwards
1251 * compatibility for files created with the prior versions of
1254 static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1256 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
1259 void ecryptfs_i_size_init(const char *page_virt, struct inode *inode)
1261 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1262 struct ecryptfs_crypt_stat *crypt_stat;
1265 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
1267 &ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat;
1268 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
1269 file_size = i_size_read(ecryptfs_inode_to_lower(inode));
1270 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1271 file_size += crypt_stat->metadata_size;
1273 file_size = get_unaligned_be64(page_virt);
1274 i_size_write(inode, (loff_t)file_size);
1275 crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED;
1279 * ecryptfs_read_headers_virt
1280 * @page_virt: The virtual address into which to read the headers
1281 * @crypt_stat: The cryptographic context
1282 * @ecryptfs_dentry: The eCryptfs dentry
1283 * @validate_header_size: Whether to validate the header size while reading
1285 * Read/parse the header data. The header format is detailed in the
1286 * comment block for the ecryptfs_write_headers_virt() function.
1288 * Returns zero on success
1290 static int ecryptfs_read_headers_virt(char *page_virt,
1291 struct ecryptfs_crypt_stat *crypt_stat,
1292 struct dentry *ecryptfs_dentry,
1293 int validate_header_size)
1299 ecryptfs_set_default_sizes(crypt_stat);
1300 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1301 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1302 offset = ECRYPTFS_FILE_SIZE_BYTES;
1303 rc = ecryptfs_validate_marker(page_virt + offset);
1306 if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED))
1307 ecryptfs_i_size_init(page_virt, d_inode(ecryptfs_dentry));
1308 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1309 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1312 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1315 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1316 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1317 "file version [%d] is supported by this "
1318 "version of eCryptfs\n",
1319 crypt_stat->file_version,
1320 ECRYPTFS_SUPPORTED_FILE_VERSION);
1324 offset += bytes_read;
1325 if (crypt_stat->file_version >= 1) {
1326 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
1327 &bytes_read, validate_header_size);
1329 ecryptfs_printk(KERN_WARNING, "Error reading header "
1330 "metadata; rc = [%d]\n", rc);
1332 offset += bytes_read;
1334 set_default_header_data(crypt_stat);
1335 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1342 * ecryptfs_read_xattr_region
1343 * @page_virt: The vitual address into which to read the xattr data
1344 * @ecryptfs_inode: The eCryptfs inode
1346 * Attempts to read the crypto metadata from the extended attribute
1347 * region of the lower file.
1349 * Returns zero on success; non-zero on error
1351 int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
1353 struct dentry *lower_dentry =
1354 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_path.dentry;
1358 size = ecryptfs_getxattr_lower(lower_dentry,
1359 ecryptfs_inode_to_lower(ecryptfs_inode),
1360 ECRYPTFS_XATTR_NAME,
1361 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
1363 if (unlikely(ecryptfs_verbosity > 0))
1364 printk(KERN_INFO "Error attempting to read the [%s] "
1365 "xattr from the lower file; return value = "
1366 "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
1374 int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
1375 struct inode *inode)
1377 u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1378 u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
1381 rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1382 ecryptfs_inode_to_lower(inode),
1383 ECRYPTFS_XATTR_NAME, file_size,
1384 ECRYPTFS_SIZE_AND_MARKER_BYTES);
1385 if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1386 return rc >= 0 ? -EINVAL : rc;
1387 rc = ecryptfs_validate_marker(marker);
1389 ecryptfs_i_size_init(file_size, inode);
1394 * ecryptfs_read_metadata
1396 * Common entry point for reading file metadata. From here, we could
1397 * retrieve the header information from the header region of the file,
1398 * the xattr region of the file, or some other repository that is
1399 * stored separately from the file itself. The current implementation
1400 * supports retrieving the metadata information from the file contents
1401 * and from the xattr region.
1403 * Returns zero if valid headers found and parsed; non-zero otherwise
1405 int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
1409 struct inode *ecryptfs_inode = d_inode(ecryptfs_dentry);
1410 struct ecryptfs_crypt_stat *crypt_stat =
1411 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1412 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1413 &ecryptfs_superblock_to_private(
1414 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1416 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1418 /* Read the first page from the underlying file */
1419 page_virt = kmem_cache_alloc(ecryptfs_header_cache, GFP_USER);
1424 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1427 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1429 ECRYPTFS_VALIDATE_HEADER_SIZE);
1431 /* metadata is not in the file header, so try xattrs */
1432 memset(page_virt, 0, PAGE_SIZE);
1433 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
1435 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1436 "file header region or xattr region, inode %lu\n",
1437 ecryptfs_inode->i_ino);
1441 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1443 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1445 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1446 "file xattr region either, inode %lu\n",
1447 ecryptfs_inode->i_ino);
1450 if (crypt_stat->mount_crypt_stat->flags
1451 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1452 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1454 printk(KERN_WARNING "Attempt to access file with "
1455 "crypto metadata only in the extended attribute "
1456 "region, but eCryptfs was mounted without "
1457 "xattr support enabled. eCryptfs will not treat "
1458 "this like an encrypted file, inode %lu\n",
1459 ecryptfs_inode->i_ino);
1465 memset(page_virt, 0, PAGE_SIZE);
1466 kmem_cache_free(ecryptfs_header_cache, page_virt);
1472 * ecryptfs_encrypt_filename - encrypt filename
1474 * CBC-encrypts the filename. We do not want to encrypt the same
1475 * filename with the same key and IV, which may happen with hard
1476 * links, so we prepend random bits to each filename.
1478 * Returns zero on success; non-zero otherwise
1481 ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1482 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1486 filename->encrypted_filename = NULL;
1487 filename->encrypted_filename_size = 0;
1488 if (mount_crypt_stat && (mount_crypt_stat->flags
1489 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) {
1491 size_t remaining_bytes;
1493 rc = ecryptfs_write_tag_70_packet(
1495 &filename->encrypted_filename_size,
1496 mount_crypt_stat, NULL,
1497 filename->filename_size);
1499 printk(KERN_ERR "%s: Error attempting to get packet "
1500 "size for tag 72; rc = [%d]\n", __func__,
1502 filename->encrypted_filename_size = 0;
1505 filename->encrypted_filename =
1506 kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1507 if (!filename->encrypted_filename) {
1511 remaining_bytes = filename->encrypted_filename_size;
1512 rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
1517 filename->filename_size);
1519 printk(KERN_ERR "%s: Error attempting to generate "
1520 "tag 70 packet; rc = [%d]\n", __func__,
1522 kfree(filename->encrypted_filename);
1523 filename->encrypted_filename = NULL;
1524 filename->encrypted_filename_size = 0;
1527 filename->encrypted_filename_size = packet_size;
1529 printk(KERN_ERR "%s: No support for requested filename "
1530 "encryption method in this release\n", __func__);
1538 static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1539 const char *name, size_t name_size)
1543 (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
1544 if (!(*copied_name)) {
1548 memcpy((void *)(*copied_name), (void *)name, name_size);
1549 (*copied_name)[(name_size)] = '\0'; /* Only for convenience
1550 * in printing out the
1553 (*copied_name_size) = name_size;
1559 * ecryptfs_process_key_cipher - Perform key cipher initialization.
1560 * @key_tfm: Crypto context for key material, set by this function
1561 * @cipher_name: Name of the cipher
1562 * @key_size: Size of the key in bytes
1564 * Returns zero on success. Any crypto_tfm structs allocated here
1565 * should be released by other functions, such as on a superblock put
1566 * event, regardless of whether this function succeeds for fails.
1569 ecryptfs_process_key_cipher(struct crypto_skcipher **key_tfm,
1570 char *cipher_name, size_t *key_size)
1572 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
1573 char *full_alg_name = NULL;
1577 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
1579 printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
1580 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
1583 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1587 *key_tfm = crypto_alloc_skcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1588 if (IS_ERR(*key_tfm)) {
1589 rc = PTR_ERR(*key_tfm);
1590 printk(KERN_ERR "Unable to allocate crypto cipher with name "
1591 "[%s]; rc = [%d]\n", full_alg_name, rc);
1594 crypto_skcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1596 *key_size = crypto_skcipher_default_keysize(*key_tfm);
1597 get_random_bytes(dummy_key, *key_size);
1598 rc = crypto_skcipher_setkey(*key_tfm, dummy_key, *key_size);
1600 printk(KERN_ERR "Error attempting to set key of size [%zd] for "
1601 "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name,
1607 kfree(full_alg_name);
1611 struct kmem_cache *ecryptfs_key_tfm_cache;
1612 static struct list_head key_tfm_list;
1613 struct mutex key_tfm_list_mutex;
1615 int __init ecryptfs_init_crypto(void)
1617 mutex_init(&key_tfm_list_mutex);
1618 INIT_LIST_HEAD(&key_tfm_list);
1623 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1625 * Called only at module unload time
1627 int ecryptfs_destroy_crypto(void)
1629 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1631 mutex_lock(&key_tfm_list_mutex);
1632 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1634 list_del(&key_tfm->key_tfm_list);
1635 crypto_free_skcipher(key_tfm->key_tfm);
1636 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1638 mutex_unlock(&key_tfm_list_mutex);
1643 ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1646 struct ecryptfs_key_tfm *tmp_tfm;
1649 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1651 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1653 (*key_tfm) = tmp_tfm;
1658 mutex_init(&tmp_tfm->key_tfm_mutex);
1659 strncpy(tmp_tfm->cipher_name, cipher_name,
1660 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
1661 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
1662 tmp_tfm->key_size = key_size;
1663 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1664 tmp_tfm->cipher_name,
1665 &tmp_tfm->key_size);
1667 printk(KERN_ERR "Error attempting to initialize key TFM "
1668 "cipher with name = [%s]; rc = [%d]\n",
1669 tmp_tfm->cipher_name, rc);
1670 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1675 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
1681 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1682 * @cipher_name: the name of the cipher to search for
1683 * @key_tfm: set to corresponding tfm if found
1685 * Searches for cached key_tfm matching @cipher_name
1686 * Must be called with &key_tfm_list_mutex held
1687 * Returns 1 if found, with @key_tfm set
1688 * Returns 0 if not found, with @key_tfm set to NULL
1690 int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1692 struct ecryptfs_key_tfm *tmp_key_tfm;
1694 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1696 list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1697 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1699 (*key_tfm) = tmp_key_tfm;
1709 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1711 * @tfm: set to cached tfm found, or new tfm created
1712 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1713 * @cipher_name: the name of the cipher to search for and/or add
1715 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1716 * Searches for cached item first, and creates new if not found.
1717 * Returns 0 on success, non-zero if adding new cipher failed
1719 int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_skcipher **tfm,
1720 struct mutex **tfm_mutex,
1723 struct ecryptfs_key_tfm *key_tfm;
1727 (*tfm_mutex) = NULL;
1729 mutex_lock(&key_tfm_list_mutex);
1730 if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1731 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1733 printk(KERN_ERR "Error adding new key_tfm to list; "
1738 (*tfm) = key_tfm->key_tfm;
1739 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1741 mutex_unlock(&key_tfm_list_mutex);
1745 /* 64 characters forming a 6-bit target field */
1746 static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1749 "klmnopqrstuvwxyz");
1751 /* We could either offset on every reverse map or just pad some 0x00's
1752 * at the front here */
1753 static const unsigned char filename_rev_map[256] = {
1754 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1755 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1756 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1757 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1758 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1759 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1760 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1761 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1762 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1763 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1764 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1765 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1766 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1767 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1768 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
1769 0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */
1773 * ecryptfs_encode_for_filename
1774 * @dst: Destination location for encoded filename
1775 * @dst_size: Size of the encoded filename in bytes
1776 * @src: Source location for the filename to encode
1777 * @src_size: Size of the source in bytes
1779 static void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
1780 unsigned char *src, size_t src_size)
1783 size_t block_num = 0;
1784 size_t dst_offset = 0;
1785 unsigned char last_block[3];
1787 if (src_size == 0) {
1791 num_blocks = (src_size / 3);
1792 if ((src_size % 3) == 0) {
1793 memcpy(last_block, (&src[src_size - 3]), 3);
1796 last_block[2] = 0x00;
1797 switch (src_size % 3) {
1799 last_block[0] = src[src_size - 1];
1800 last_block[1] = 0x00;
1803 last_block[0] = src[src_size - 2];
1804 last_block[1] = src[src_size - 1];
1807 (*dst_size) = (num_blocks * 4);
1810 while (block_num < num_blocks) {
1811 unsigned char *src_block;
1812 unsigned char dst_block[4];
1814 if (block_num == (num_blocks - 1))
1815 src_block = last_block;
1817 src_block = &src[block_num * 3];
1818 dst_block[0] = ((src_block[0] >> 2) & 0x3F);
1819 dst_block[1] = (((src_block[0] << 4) & 0x30)
1820 | ((src_block[1] >> 4) & 0x0F));
1821 dst_block[2] = (((src_block[1] << 2) & 0x3C)
1822 | ((src_block[2] >> 6) & 0x03));
1823 dst_block[3] = (src_block[2] & 0x3F);
1824 dst[dst_offset++] = portable_filename_chars[dst_block[0]];
1825 dst[dst_offset++] = portable_filename_chars[dst_block[1]];
1826 dst[dst_offset++] = portable_filename_chars[dst_block[2]];
1827 dst[dst_offset++] = portable_filename_chars[dst_block[3]];
1834 static size_t ecryptfs_max_decoded_size(size_t encoded_size)
1836 /* Not exact; conservatively long. Every block of 4
1837 * encoded characters decodes into a block of 3
1838 * decoded characters. This segment of code provides
1839 * the caller with the maximum amount of allocated
1840 * space that @dst will need to point to in a
1841 * subsequent call. */
1842 return ((encoded_size + 1) * 3) / 4;
1846 * ecryptfs_decode_from_filename
1847 * @dst: If NULL, this function only sets @dst_size and returns. If
1848 * non-NULL, this function decodes the encoded octets in @src
1849 * into the memory that @dst points to.
1850 * @dst_size: Set to the size of the decoded string.
1851 * @src: The encoded set of octets to decode.
1852 * @src_size: The size of the encoded set of octets to decode.
1855 ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
1856 const unsigned char *src, size_t src_size)
1858 u8 current_bit_offset = 0;
1859 size_t src_byte_offset = 0;
1860 size_t dst_byte_offset = 0;
1863 (*dst_size) = ecryptfs_max_decoded_size(src_size);
1866 while (src_byte_offset < src_size) {
1867 unsigned char src_byte =
1868 filename_rev_map[(int)src[src_byte_offset]];
1870 switch (current_bit_offset) {
1872 dst[dst_byte_offset] = (src_byte << 2);
1873 current_bit_offset = 6;
1876 dst[dst_byte_offset++] |= (src_byte >> 4);
1877 dst[dst_byte_offset] = ((src_byte & 0xF)
1879 current_bit_offset = 4;
1882 dst[dst_byte_offset++] |= (src_byte >> 2);
1883 dst[dst_byte_offset] = (src_byte << 6);
1884 current_bit_offset = 2;
1887 dst[dst_byte_offset++] |= (src_byte);
1888 current_bit_offset = 0;
1893 (*dst_size) = dst_byte_offset;
1899 * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
1900 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
1901 * @name: The plaintext name
1902 * @length: The length of the plaintext
1903 * @encoded_name: The encypted name
1905 * Encrypts and encodes a filename into something that constitutes a
1906 * valid filename for a filesystem, with printable characters.
1908 * We assume that we have a properly initialized crypto context,
1909 * pointed to by crypt_stat->tfm.
1911 * Returns zero on success; non-zero on otherwise
1913 int ecryptfs_encrypt_and_encode_filename(
1914 char **encoded_name,
1915 size_t *encoded_name_size,
1916 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
1917 const char *name, size_t name_size)
1919 size_t encoded_name_no_prefix_size;
1922 (*encoded_name) = NULL;
1923 (*encoded_name_size) = 0;
1924 if (mount_crypt_stat && (mount_crypt_stat->flags
1925 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
1926 struct ecryptfs_filename *filename;
1928 filename = kzalloc(sizeof(*filename), GFP_KERNEL);
1933 filename->filename = (char *)name;
1934 filename->filename_size = name_size;
1935 rc = ecryptfs_encrypt_filename(filename, mount_crypt_stat);
1937 printk(KERN_ERR "%s: Error attempting to encrypt "
1938 "filename; rc = [%d]\n", __func__, rc);
1942 ecryptfs_encode_for_filename(
1943 NULL, &encoded_name_no_prefix_size,
1944 filename->encrypted_filename,
1945 filename->encrypted_filename_size);
1946 if (mount_crypt_stat
1947 && (mount_crypt_stat->flags
1948 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))
1949 (*encoded_name_size) =
1950 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
1951 + encoded_name_no_prefix_size);
1953 (*encoded_name_size) =
1954 (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
1955 + encoded_name_no_prefix_size);
1956 (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
1957 if (!(*encoded_name)) {
1959 kfree(filename->encrypted_filename);
1963 if (mount_crypt_stat
1964 && (mount_crypt_stat->flags
1965 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) {
1966 memcpy((*encoded_name),
1967 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
1968 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
1969 ecryptfs_encode_for_filename(
1971 + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
1972 &encoded_name_no_prefix_size,
1973 filename->encrypted_filename,
1974 filename->encrypted_filename_size);
1975 (*encoded_name_size) =
1976 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
1977 + encoded_name_no_prefix_size);
1978 (*encoded_name)[(*encoded_name_size)] = '\0';
1983 printk(KERN_ERR "%s: Error attempting to encode "
1984 "encrypted filename; rc = [%d]\n", __func__,
1986 kfree((*encoded_name));
1987 (*encoded_name) = NULL;
1988 (*encoded_name_size) = 0;
1990 kfree(filename->encrypted_filename);
1993 rc = ecryptfs_copy_filename(encoded_name,
2002 * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
2003 * @plaintext_name: The plaintext name
2004 * @plaintext_name_size: The plaintext name size
2005 * @ecryptfs_dir_dentry: eCryptfs directory dentry
2006 * @name: The filename in cipher text
2007 * @name_size: The cipher text name size
2009 * Decrypts and decodes the filename.
2011 * Returns zero on error; non-zero otherwise
2013 int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
2014 size_t *plaintext_name_size,
2015 struct super_block *sb,
2016 const char *name, size_t name_size)
2018 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2019 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
2021 size_t decoded_name_size;
2025 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
2026 && !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
2027 && (name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
2028 && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2029 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
2030 const char *orig_name = name;
2031 size_t orig_name_size = name_size;
2033 name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2034 name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2035 ecryptfs_decode_from_filename(NULL, &decoded_name_size,
2037 decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
2038 if (!decoded_name) {
2042 ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
2044 rc = ecryptfs_parse_tag_70_packet(plaintext_name,
2045 plaintext_name_size,
2051 printk(KERN_INFO "%s: Could not parse tag 70 packet "
2052 "from filename; copying through filename "
2053 "as-is\n", __func__);
2054 rc = ecryptfs_copy_filename(plaintext_name,
2055 plaintext_name_size,
2056 orig_name, orig_name_size);
2060 rc = ecryptfs_copy_filename(plaintext_name,
2061 plaintext_name_size,
2066 kfree(decoded_name);
2071 #define ENC_NAME_MAX_BLOCKLEN_8_OR_16 143
2073 int ecryptfs_set_f_namelen(long *namelen, long lower_namelen,
2074 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
2076 struct crypto_skcipher *tfm;
2077 struct mutex *tfm_mutex;
2078 size_t cipher_blocksize;
2081 if (!(mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
2082 (*namelen) = lower_namelen;
2086 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
2087 mount_crypt_stat->global_default_fn_cipher_name);
2093 mutex_lock(tfm_mutex);
2094 cipher_blocksize = crypto_skcipher_blocksize(tfm);
2095 mutex_unlock(tfm_mutex);
2097 /* Return an exact amount for the common cases */
2098 if (lower_namelen == NAME_MAX
2099 && (cipher_blocksize == 8 || cipher_blocksize == 16)) {
2100 (*namelen) = ENC_NAME_MAX_BLOCKLEN_8_OR_16;
2104 /* Return a safe estimate for the uncommon cases */
2105 (*namelen) = lower_namelen;
2106 (*namelen) -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2107 /* Since this is the max decoded size, subtract 1 "decoded block" len */
2108 (*namelen) = ecryptfs_max_decoded_size(*namelen) - 3;
2109 (*namelen) -= ECRYPTFS_TAG_70_MAX_METADATA_SIZE;
2110 (*namelen) -= ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES;
2111 /* Worst case is that the filename is padded nearly a full block size */
2112 (*namelen) -= cipher_blocksize - 1;